Popular Science Monthly 1929-04: Vol 114 Iss 4

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FEB2 8 1929 April 1929 25 cents MONTHLY Founded 1872 Aviation ~Radio ~Automobiles ~Home Building Engineering-Exploration»” The HomeWorkshop New Ideas:

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YOUTHEUOL CHRAFTAMEN “Money -Back” | Guaranty Try one can of Rogers : Brushing Lacquer. {not more than satisfied, re- | | turn what is left to you: dealer. Ie isau to refund the entire pur- 3 chase price. ¥ ry MOTHER AND THE GIRLS THE MAN OF THE HOUSE The whole family now uses “Rogers” actually “Dries while you wait.” Dries smooth, without laps or brush marks. Dries to a tough, porcelain - like hard- ness that wears and wears and WEARS. OYS, too impatient to wait upon slow drying finishes, find “Rogers” ideal for boats, skooters, wagons and many other things. Women and girls who never before attempted “artistic” things, are now doing exquisite work with ““Rogers”—the guar- anteed brushing lacquer. And the men folks, alive to the unusual saving of time and labor, endorse this amazing, modern finish for the numerous practical things found in any home. Dries while you wait No experience is required to use depend- ‘ able “Rogers.” Anyone can do it. You merely flow on the exquisite colors witha full brush. Right over old or new surfaces. “Rogers” quickly levels itself. Then it ACME WHITE LEAD AND COLOR WORKS, Detroit THE SHERWIN-WILLIAMS CO., Cleveland, O. PENINSULAR PAINT & VARNISH CO., Detroit - LACQUER LETTUCE GREEN Also distributed and guaranteed by Choice of 26 exquisite colors Genuine “Rogers” comes in 26 exquisite, up-to-date colors. Also black, white and clear. In addition you can now get six new dark shades designed for outdoor s well as indoor use, and hard usage. SGeouine “Rogers” is sold by the leading - hardware and department stores everywhere, in the familiar “‘oriental”’ con- tainer illustrated to the left. Every can is sold on our “money-back” guaranty. Detroit White Lead Works, Detroit, Michigan, Makers of Highest Grade Paints, Varnishes, Colors, Lacquers. TT ET * LINCOLN PAINT AND COLOR COMPANY, Lincoln, Nebr. : THE MARTIN-SENOUR CO., Chicag°® THE SHERWIN-WILLIAMS CO., OF CANADA, LTD., Montreal, Can. . LEWIS BERGER & SONS, LTD., London, Eng., and Sydney, Australia. THE SHERWIN-WILLIAMS CO., London, Eng., and Sydney, Australia

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Dries ks. » hard. EARS. : quisite, ite and get six utdoor ge. eading stores 1” con- can is ty. etroit, Paints, Se Chicago \, LTD., Lustralia

Apart, 1929 Where Best to Buy AGOODUSEDCAR |

Your Cadillac-La Salle dealer occupies the most advanta- geous position in the buying Tu: used car market, generally speaking, offers many excellent values. Only a few simple and common- sense considerations are needed to guide the buyer in this field. The first of these is the position and standing of the dealer from whom the used car is to be purchased and the line of new cars he handles. It is obvious that if his new cars are the recognized leaders in their price division he hasa considerableadvan- tage over his so-called competitors. The demand for his line and the public’s receptive state of mind are such that he is not tempted to over- appraise trade-ins.

and selling of Used Cars—as well as New Cars <- 7 + POPULAR SCIENCE MONTHLY 1

This, as is well known, is the for- tunate position of all Cadillac-La Salle dealers. It is generally recog- nized that if you want the kind of performance, the measure of safety and ease and the inimitable beauty that Cadillac and La Salle offer, you must buy a Cadillac or La Salle. They are the accepted leaders of the finest of fine cars. Consequently the used cars these dealers offer are fairly priced and the stocks are large and varied. You may be assured that these cars are well conditioned and represent exceptional values because every Cadillac-La Salle dealer is eager to retain your good will. CADILLAC MOTOR CAR COMPANY Division of General Motors Corporation Detroit, Michigan Oshawa, Canada Hy ee a

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POPULAR SCIENCE MONTHLY APRIL, 1999 ———————— LEADING ARTICLES ii Astronomy ‘ ” ee, ee ; Poison in Comets. . 46 EtnstErn’s Topsy-Turvy Worip + By Alden P. Armagnac 17 Bolt of fron Cast from the Sky | 49 Startling aspects of the new theory of Nature’s forces Saw Ghalis te OS ; bang oon,“ , g s Measured by Sa!—Tuey’reE Fiumine “Takies”! , By Norman Foster 20 Photo-Electric Cell 54 An actor’s vivid story of sound pictures in the making Pinpoint Device Registers Heat f: PLANNING A 44-MILE TUNNEL! ; By George Lee Dowd, Jr. 22 For Suns. e at from 56 How engineers aim giant tubes at an invisible bull’ s-eye Light from Tumbling Suns Arrives i in A Macurne Tuat Makes Heroes By H. C. Davis 23 800 Years 70 The thrilling role of the radio compass in rescues at sea Fiyers Open THE Wor p's Ice Box . By Edwin W. Teale 24 . Strange mysteries of the Antarctic revealed Automobiles SwitcHiInc ON THE SuN . By Roberi E. Martin 27 How to choose and use a health lamp —- Speedy Challenger - 34 I Am Learnine To Be a Fiyer, Part IT By Larry Brent 28 ar wry a YS S. << eee 35 A student pilot’s story of his first trip in the air Oil a dae ra led = RUNNING A SKYSCRAPER . : ; By Peier Vischer 31 Gilded Auto of 1903 Still Runs in Odd experiences of the ‘‘mayor’ ’ of a perpendic ular town Fine Style 57 Tue Biccest ENGINEERING Jos Hoover Ever TackLeD See Gaekee 61 E . ; By Will Irwin 32 Keeping Windshield Wiper Working 90 A keen analysis of our new President by an old friend Convenient Tool Pockets A 90 Tue Reaw Fatuers or Fuicut, Part IV By John R. McMahon 42 Trick Valve-Grinding Tool 90 How Wilbur and Orville Wright soared on wings at last A Self-Starting Siphon 90 Wircues—STiLL ON THE Jos! By Arthur A, Stuart 45 Running-Board Tire Rack 90 Curious results of the human mind’s craving for wonders Ten Dollars for an Idea! . 90 CANNONBALL BAKER, AUTOMOBILE “ BroncHO Buster” Tells his story to Henry Morton Robinson 50 Te Thrilling adventures of a famous road racer Aviation Are You IN THE Ricut Jos? By Ruth Moore Morriss 52 Psychologists prepare new tests of your personality U. S. Gliders Match Skill 34 SLAYING THE Ice Monsters . By Michel Mok 53 Painting On a Plane’s License Plates r How experts trail bergs and blow them up esathon*s Ratedt Ais timee 40 Launching the First Steam-Driven ° Dirigible . 40 SPECIAL FEATURES A Revolutionary | New Airplane Motor . 40 Cover DssIen . By Herbert Paus Gasoline Gage Marvel of Accuracy . 40 FINANCIAL RACKETEERS By Wallace Ames 4 Super-Sensitive Altimeter Detects The financial editor’s monthly advice Five-Foot Drop - - : 40 REFRIGERATOR OR GERM-BREEDER? . . « By F.G. Pryor 12 ag sees Flying Hotel for 80 Why many ice boxes are a menace to health ones 41 Transcontinental Air-Rail Route 41 Our Reapers Say . 14 - a $900,000 Wind Tunnel . 41 GumpsEs or PeorLe WortH KNow1ING : 26 A Helicopter That Works? 41 Thumbnail sketches of outstanding personalities New Goggles for Airmen 41 Back or THE Montn’s News ; By Karl Vooght 46 Britain’s “Question Mark” 41 Interesting facts and comment illuminating the latest events in science Rescued from the Tree Top . 46 GETTING THE Best Tone FroM Dynamic SPEAKERS Wing Strength Tested by Piles of By Alfred P. Lane 62 Sandbags 54 How to build a radio baffle board Lindbergh's Trophies Fill Wing of THREE Way* To Burtp a Rapio By John Carr 65 Memorial 54 Timely suggestions that will help you to ‘choose a design Planes Glide into River Like Ducks 54 Lockx1ne Out tHE Heat anp Cop . By William Dewey Foster '74 Sturdy Monoplane Wears Stream- Inside facts about insulation in house building lined “Pants” . 55 Wuo Can Matcu Tuts SHop? . 79 bees: ty Out Giant 12-Passen- One of the world’s most perfectly equipped home workshops ger Plane - 55 Turnine Fancy Boxes anp Bow Ls . By Herman Hjorth 80 R-100 Passengers to Land on 5 How t the wood-turning lathe to best advantage Oe ee, - ™ a —s 8 Sign of the Pawnbroker Urged as Air EDITORIALS . ‘ . 82 Masker 57 Ir Your Heapuicuts Went Ovur— . " By Martin Bunn 84 Graf Zeppelin to Explore Arctic near Gus gives the rules for safe driving Alaska . 58 A Lieut Hanp on THE WRENCH . By Henry Simon 96 War Birds Flit from Floating } Nest Secrets of handling tools 4 Built like Dovecote 71 {Dril, 1020. Ln.9 1M, Ba. 4 ow one a oy peonta ~~ 4 Ly Fo ay 4 Ba ww pA Baten, | its po poepeione, ay Canete, 93. 50; ferdqn countries, “ me The __ Ine. Entered ‘s sosond <tass matter 28, it 8, at the Post Office at — in its editorial columns ‘Samereus "stories of new Products. ‘ot ap ied New York under the act of March 3, 1879; additional entry as second-class science, Popular Science Monthly does not underwrite the business methods matter at Chicago, Illinois. Entered as second-class matter at the Post Office of the individuals or concerns ucing them. The use of Popular Science papartunees Canada. Printed in U. 8. Copyright, 1929, Ld the Popular Monthly articles for stock-selling schemes is never a O. B. Capen, Science Publishing Co., Inc. Single copy, ADs cents. Yearly subscriptions to President and Treasurer; R. C. Wilson, Vice-President; A. L. Cole, Secretary.

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L, 1929 — 6 9 4 Noor = Sea ae a Oe Ge —— Se a Apnit, 1929 POPULAR SCIENCE MONTHLY —$=$—$—S —_—————_ Huge Searchlight’s Beam Will Guide Air Liners Chicago ‘ ‘Hub” 565,406 Miles Engineering nching a 500-Ton Gate . Why Not Weld Them All? New Dredge Driven by Motors . H England Seeks Fog-Proof Building Materials. Six-Ton Slate Block “Hoisted from Quarry Saitinadl ——s He’s Inventor, Executive, and Rail- way Conductor . Snake Guardian a Part- Time Weath- er Prophet .. World’s Only Masters of Strange Inlaying Craft . . Doctor Helps Cripples ‘with Own Free Inventions f Builds Sailing Yacht of Turkey Bones Paints “ Einstein’’ Pictures of ‘‘Ener- "in Art. Mail Carrier Has “ Circled Earth” Seven Times. Pedals 175,000 Miles on Bicy cles in 20 Years A Riveter for 50 Years, He Claims the Record . Health and ns Sciences Combine to Save King George’s Life. Dyeing the Blood to Keep You from Dying . . 2 Key to Long Life?. Finds Some Germs Prefer. Blonds for Victims . Can You Give a Name to Ultra- Violet Ray? . ; Boys Build. “Human Engine” in Study of Anatomy Three Chemicals of Life Flow in Our Blood Physician Feeds Patient Through Pings + inSkin . . ' in Medicine for Planes Flying Diesel “Magic” Laboratory Discoveries Chemist Claims New Way to Harden Precious Metals ; Five Million Volts! . Testing with Mechanical Hands’ Study X-Rays behind Barricade Tells How Wind Sways Towers Smallest Torch Reveals senate Life ‘ ; ney Nature Fresh ‘‘ Milk’ Right from the Bark Why Sap Rises. First American Cat Had Teeth Like Daggers . Python Takes ‘Whole Deer at One Gulp . “Sneezing” ’ Plants Spray Their Seeds into Air . Zoologists Seek to Save Whale from Extinction . . Walnut Trees Kill Plants. Whale Eats Millions of Shrimp for Lunch Salamanders Grow Eyes New Devices for the Home Nonskid Anchors for Your Rugs A New Automatic Toaster . ... Latest Dishwasher Wheels to Table No Tears in Onion Chopping @ New Adjustable Can-Opener . 76 © Old Letter May Tell Secret of 71 | Combination Ice Pick and’ Bottle “Strad”’ 59 Opener . “aaa 76 | Would Banish Cupid for Rule of 72 | Safety Lock for Gas Cocks . . .° 77 Eugenics. 59 A Stand for Your Razor. . . . 77 | Electric “Bos'n” Shouts Orders on Novel “Cooking Cabinet” . . . 77 Warship . 60 34 Wall Recess Guards Hot fron . . 77 | Quake Takes a Short Cut through 47 Handy New Broom and Mop Holder 177 Earth’s Center . 60 Miniature Washboard for Dainties. 77 | Angel Fish Brings Deadly Bacillus to 56 N P d Aquarium . 60 ew fFrocesses an i Much Do You Know about hysics?. 60 - ; Inventions Finds Germs Existed Before Dino- 66 | Lrain Obeys Its Master’s Voice . 35 saurs. . ayiteg 61 Ready-Lighted Cigarettes Pop from Wanted—Three-Eyed Fish! . 61 This Holder. . 60 | Discovers Vast Plateau on Brazilian Deliveries Locked Up by Kitchen- Border : 66 Wall Receiver . 60 | Tear Gas Warns of Poison 67 36 | Devises Weights to Stop Trains from Sandbags to Strengthen Hands of Crashing. 61 Pianists . 67 36 | Lock-It-Open Latch Foils Winds and Want White Hair? Then Use X-Ray Robbers... 61 “Bleach”’ 67 36 | Automatic Device Sends Out S OS Underground Gold Vault Rivals Cals... 61 Hugo’s Fiction . . 68 36 | Divider Slices Pies into Cuts of The Same Old Money, but in 57 Equal Size . 67 Smaller Paper Bills. 68 Dials Show Time-Table of Trains at Gas Masks to Be Used in Fight on 67 aGlance 68 Hay Fever . 69 Folding Bicycle C arried Like a Type- Detects Secret Message by Shading 69 writer. 68 of the Ink ; 70 Crashless C rossing ‘Gates Bend Like Gunny Sacks from Banana Trees . 170 69 a Bow 69 | A Trainload of Gasoline Goes Up in Double-W alled Pot Keeps Flowers Smoke 70 69 Watered. . 72 | Lower California Is Rising from the Sea 70 P heegrephy Finds Babies Are Normal Despite So lms “ : Parents’ Ages. 71 46 ie a will: a" ie ee 60 “= Beauties Skate on n Sunproof os Aerial C Snaps 46 ao. nap New Canyon 79 | One Twist of the Wrist Sprinkles 10 48 | Tiny Camera Photographs Inside of Acres. 72 Stomach. . 72 — Prancing Trains Postmen is 56 | Dressing Up Your Photographs | . 8 to Walk. . Taking Pictures Backward . . . 104 —_ Manufactures Its Stained 7 rR stles Movies ... ass Windows . 57 | Titles for Amateur Movies 127 Many Usea Combined in One Water. , ing Can . 73 = Radio Canadians Will Use Peat to Reduce 58 Radio’s Puzzles. 49 Coal Bills. 73 a How to Hook a Phonograph to Your Snake Bites Killed 27 in U. S. in a Set 64 Year . : 73 Tone Quality from Records . . 64 Special Receivers .. os « ae aBCed Rae oa For the Home Owner Researchers Baffled by Six Radio More Closet Space. — Mysteries . . 67 | Emptying a Washing Machine . . 102 36 Controlling a Bathroom Light . 102 46 Unusual Facts and I ea How to Tell Wool from Cotton. . 115 47 | Teaching a Young Gorilla Tricks . 36 | How to Do et titiistal with sai tied 47 | Odd as the House Jack Built . . 37 Guns . 122 48 | Pulls Train a Miles Long! . . 38 Handy M, Around the Poleina Saucer . . 39 69 | The World’s Healthiest “Spuds” . 48 Ideas f or the Han 0, Payee Benjamin Franklin’s Broom . . 48 | Sewing Table in Modern Style . 78 What Is the Right Size? . . . . 48 | Hammering Out Metal Trays 81 49 | New WondersinGlass . . . . 49 | One Bench That’s Big Enough . 94 49 | Tests Breath of Honeybees . . 54 | Turning a Flag into an Egg . . 104 Test “Cast Stone”’ Strength with Landing Gear for Model Planes 106 58 Tiny Cylinders. . 55 | Blueprints for Your Home Work- Tiny Propeller on Man’s Back Pushes shop . . 108 58 Him Uphill... 56 | Metal Fastenings for Woodwork . 110 Motor Boat Leaps through ¢ a Hoop 56 | Turning Large Work on a Small 61 | Use Poison Gas to Rout Foes of Lathe. 112 Pineapples . . . 56 | Novel Way to Bend Bamboo for 66 | These “Cukes”’ Cannot Fail. 57 Model Airplanes. . 12 66 | Plans to Use Tung Nuts for Making How to Display a Ship Model . . 114 Paint Oil. 57 | Mixing a Low-Cost Varnish Re- 71.| Electrified W. ater Keeps } Fish Out of mover. 116 71 Ditches .. é 57 | Small Baltimore Clipper Model Is Nitrates from Africa . 58 Easy to Make 121 Hoard in England Adds to ‘Bronze Parrafin Seals Paint Cans. 124 Age Mystery. 58 | You Must “Strike Gold” to Win 76 Five Years’ Work to Quarry One This Game . 125 76 Block of Marble. 59 | Small Crucible Made from a Battery 76 | Gas Blows Up Mile of London Carbon 128 76 4 «Streets ; 59 4 Inner Tube Makes a Punching Bag 128

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INCREASE your Income with 6; v4 Bonds LL-SECURED First Mortgage Bonds on modern income-producing city buildings give you the opportunity to increase your yield without sacrificing the good security of your prin- cipal. Offerings of The F. H. Smith Company are held by men and women in 48 States and in more than 55 foreign countries and terrifdries. Bonds have the protection of a system of safeguards de- veloped through fifty - six years of experience. DENOMINATIONS: $1,000, $500, $100; coupons payable semi-annually. Valuable State and Federal tax provisions in- crease the gross yield. We shall be glad to make you familiar with the attractive fea- tures of the 614% First Mort- gage Bonds and other types of securities we offer, and to give recommendations for increas- ing your income while safe- guarding your principal. Send in your name and address on the form below for descrip- tive circulars and our latest booklet. Tue E H.SmiraCo. Investment Securities— Founded 1873 Smith Bldg., Washington, D.C. 285 Madison Ave., New York City Branch offices in Other Cities Te eee ee eee eee eee eee eee eee) CeO OOOOH HEHEHE HEHEHE EEO POPULAR SCIENCE MUNTHLY Financial Racketeers By WALLACE AMES, Financial Editor I—BROADWAY ALE HATCH was lonesome. A D tough day in the big city and din- ner alone left him in no mood to take interest in the movies or the thea- tres of Times Square. His mail from home only made him feel more lonesome. He went down to the hotel Jobby and just sat . . . looking the picture of loneliness. When a companionable sort of chap sitting near-by asked for a light it was no trick to get conversation started. And while Dale was talking about the lone- liness of a big city another individual found a pretext to join the group. He had a big-city grouch too... he had been over-charged, short-changed and stung by gambling devices and he be- wailed the heartlessness of New York. Recounting some of his experiences in a Southern drawl, he revealed the fact that he was an easy mark. Which gave the companionable chap a lofty idea. “This sap is primed and ready for some confidence man,’ whispered Dale’s newly made friend, while the Southern gentleman momentarily left them alone. “Let’s do him a good turn... give him a demonstration of how easily he can be roped in . . . then explain the stunt to him, give him back his money and maybe in that way he will learn not to be | such easy meat for racketeers. “We'll mateh coins, you always play- ing heads and [I tails, so our Southern friend will always lose to one of us.” First they matched for a dollar, then five, then ten. Dale and the compan- 1 ionable chap won alternately. Each time the Southerner got more excited . - « insisting that his luck would turn, and continually raising the stakes, to twenty-five, fifty and finally to a hun- dred. It so happened that the com- panionable chap won all the big plays and as he did not exhibit any hurry to reveal the secret, drive home the lesson and return the money, Dale finally took it upon himself to “spill the beans.” Up in the air went ‘the hot-blooded | Southerner. “You're just a couple of dirty crooks!” he bellowed out. “And you think you can get away with that, right here on Broadway! I'll show you guys.” Dale's explanation didn’t seem to register at all. The Southerner was fiery mad, full of threats and all touched off to start a young riot. A man who spoke as though he were a detective stepped up and inquired the cause of the excitement. While the Southerner was explaining, the com- panionable chap dove into a taxi and was soon lest in the traffic. The South- | erner gave chase, evidently to recover his money. Dumfounded by the turn of affairs and considerably over-awed by the threatening manner of the “detec- tive,’ Dale Hatch didn’t know what to do. Finally Dale was told to beat it and was advised not to get caught again violating the state laws against gamblj Dale Hatch lost his expense money and had to draw on his firm for more, When he returned home and explained the circumstances to his sales manager he had to stand for a lot of ridiculj Of course the sales manager, Robert Hayes, would himself never fall for such a sucker trick. Take it from him, he wouldn’t. Let’s see just how shrewd he really was. II—WALL STREET Robert Hayes was getting ahead nicely. From a substantial income he was able to lay aside about $150 a month —nearly $2,000 a year. About the time Dale Hatch returned from his trip, Hayes received a call from a representa- tive of a “big” New York bond house. Hayes had never heard of the firm, but it must be big... one or two former United States Government officials were members . . . and furthermore, the rep- resentatives sought to interest Hayes only in the highest grade of investments, When Hayes showed an interest in some- thing speculative the representative talked him out of it and persuaded him to open an account to buy some govern- ment bonds and other gilt-edge securities, paying $500 down and $150 a month. Every month Hayes received letters and printed literature, reporting on the status of his securities, reviewing eco- nomic conditions, analyzing sound in- vestment opportunities, which added to his general grasp of security matters, and inspired his confidence in his firm of in- vestment bankers. Hayes kept up his payments regularly; his wealth grew steadily; in a little over a year he had nearly completed payments on three bonds. Along about this time the literature from his bankers began to mention in- vestment opportunities of another char- acter. Interspersed between the reviews of gilt-edge bonds were suggestions re- garding stocks, in companies Hayes never heard of, but which, according to the bankers, were destined to make their shareholders rich. Big earnings... big dividends . . . chances for a big rise in the value of the shares. Just before Hayes completed payment on his three high grade bonds the se- curity representative paid him another call. This time he was all “‘het up” over a brand new industry just being organized to convert waste corn-stalks into motor fuel. Now, as a matter of fact, some 3,000 useful articles can be made of corn- stalks and corn-cobs. The door to Hayes’ office was open while he was conferring with the bond salesman. Let’s listen to the sales talk. “You know, Mr. Hayes, that our firm only deals in the highest type of in- vestments. We (Continued on page 5) APRIL, 1999 a ae >. 2 ean Ap’ \ "Fra BSS ast Ss’ a @ =. wes Se BES #828e2rnea°4a

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PRIL, 1999 We rewd he ahead ome he , month he time Strip, ‘esenta- house. , but it former ~ were he rep- Hayes -ments, 1 some- ntative zovern- urities, nth. letters on the ig eco- nd in- ded to rs, and | of in- up his | grew he had three srature ion in- r char- eViews ms re- es had ling to e thei Se. a big yment he se- nother ” over anized motor some corn- | Open t our of in- e 5) i Apa, 1929 Financial Racketeers (Continued from page 4) t any of our customers specu- —o ee yourself that I got you to put your money 1n the best bonds on the market. It is true that they only y you a little less than 5%, but your principal is safe. Still, in these times 5% ‘sn’t much income. And once in a long while we get one of those rare chances to help our customers make a bigger income and still be absolutely safe. “Think of the millions of automobiles . think of the high price of gas... think of the hundreds of millions of tons of corn-stalks going to waste every year _. picture Corn Fuel Industries, Inc. with its grinding plants dotting the entire corn belt, its pipe-lines and re- fneries and filling stations all over the United States.” Then, out of the portfolio came charts and statistics of every description, show- ing how original Standard Oil stock- holders were made fabulously rich, pic- turing possibilities of all sorts to stagger Hayes’ imagination. “That’s all very interesting,” admitted Robert Hayes, “but I am still tied up paying for my bonds; I haven't the money now, to go into this new deal, although from what you tell me about it I would like to.” ; “Maybe we can help you raise some cash,” suggested the resourceful bond man. “There is a ready market for your bonds. And you have a little profit in them, too. Suppose we sell your bonds and put that money into Corn Fuel Industries Common. Then, instead of less than $150 a year interest on your $3,000 investment, you will be getting $450 a year in dividends . . . and in less than a few months your stock should be worth several times what you now pay for it.” The deal was closed. And soon Robert Hayes discovered that he was just as big a sucker as Dale Hatch. Hatch fell prey to a Broadway Racketeer; Hayes succumbed to the craft of a Wall Street Racketeer. How nicely this Wall Street racket was worked out. The alleged investment banking firm first won Hayes’ confidence. They advised him to buy high grade se- curities. They worked on him until they convinced him that they were a con- servative, reliable house. They helped him to accumulate a considerable sum of money while winning his confidence. By selling him some perfectly good bonds, on which they made no profit, they put him into highly marketable securities, which could immediately be converted into cash when they were ready to make the “kill.”’ So the gilt-edge bonds not only helped to build confidence, but put the equivalent of cash within reach of the crooks when they got ready to reach out their hands for it. * * * The above anecdote is based on an actual form of fake security selling that was practiced for a long time by several firms. Hundreds of thousands, perhaps millions of dollars were lost by investors originally tempted (Continued on page 6) wil late. POPULAR SCIENCE MONTHLY To men who want to Quit Wor k some day HIS PAGE is addressed to those thousands of earnest, hard-working men who want to take things easier some day. It tells how these men, by following a simple, definite plan, can provide for themselves in later years a guaranteed income they cannot outlive. How the Plan Works It doesn’t matter whether your present in- ability, even if that disability should continue for many, many years—the remainder of your natural life. Get this free book The Phoenix Mutual Company, which offers you this opportunity, is a 125 million dollar company. For over three-quarters of a century it has been helping thousands of men and women to end money worries. But you’re not interested in us. You are come is large or merely average. It doesn’t mat- ter whether you are mak- ing fifty dollars a week or five hundred. If you follow this plan you will some day have an income upon which to retire. The plan calls for the deposit of -only a few dol- lars each month—the ex- act amount depending on your age. The. minute you make your first de- posit, your biggest money worries begin to disap- pear. Evenif you should become totally and per- manently disabled, you would not need to worry. Your payments would be made by us out of a spe- cial fund provided for that purpose. And not only that. We would mail you a check every month during the entire time of your dis- NEW RETIREMENT INCOME PLAN Here is what a dividend-paying $10,000 policy will do for you: It guarantees when you are 65 A Monthly Income for life of $100 which assures a return cf at least $10,000, and perhaps much more, de- pending upon how long you live. or,if you prefer, A Cash Settlement of $12,000. It guarantees upon death from any natural cause before age 65 A Cash Payment to your beneficiary of $10,000. Or $50 a month for atleast 24 years and 8 months. 6 66% 6 x. - $14,823 It guarantees upon death result- ing from accident before age 60 A Cash Payment to your beneficiary of $20,000. Or $100 a month for at least 24 years and 8 months. (| re ear $29,646 It guarantees throughout per- manent total disability which begins before age 60 A Monthly Disability Income of $100 and payment for you of all premiums. Plans for women or for retirement at ages 55 or 60 are also available. interested in what we can do for you. An illustrated, 36-page book called “How to Get the Things You Want” tells you exactly that. It tells how you can become financially inde- pendent—how you can re- tire on an income—how you can provide money for emergencies—money to leave your home free of debt—money for other needs. This financial plan is simple, reasonable, and logical. The minute you read about it you will realize why it accomplish- es such desirable results —not for failures, not for people who can’t make ends meet, but for hard- working, forward-looking people who know what they want and are ready to make definite plans to getit. No obligation. Get your copy of the book now. G) PHOENIX MUTUAL LIFE INSURANCE COMPANY Hartford Office: Hartford, Conn. First Policy issued 1851 PHOENIX MUTUAL LIFE INSURANCE CO., 424 Elm St., Hartford, Conn, Send me by mail without obligation, your new book, “Howto GEt THE THINGS YOU WANT.” Name Date of Birth Business Address__- City Home Address State

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Retire — MS years on your Present living Budget by investing in safe First Mortgage Bonds Follow the definite plan given in this book, and your financial independence is won. The plan works just as surely, whether you are now earning $1,000 or $100,000 a year. The way is certain—each step plainly indicated and absolutely safe—inde- pendent of luck, business genius or speculation. Every fact has been harvested out of the 48 years’ experience of Cochran & McCluer in the first mortgage invest- ment banking business. The plan is so simple, anyone can understand it—so definite anyone can follow it—and so certain, noonecan fail. In addition to the Financial Independ- ence Plan and the unique budget schedule, the book gives suggestions that enable you to enjoy more of the good things of life, both while build- ing your independent fortune and after you have attained it. We invite the most skeptical to read this plain, straightforward, interesting book. Send coupon. We employ no sales- men, therefore none will call. 4 Cochran & McCluer Co. li 46 N. Dearborn St., Chicago, Ill. Please send me, without obligation, your book, “How To Retire In 15 Years.” Mail this | REE ES aR Sane pee Cochran &M‘Cluer Co. Established 1881—Never a loss to any investor. 46 North Dearborn Street, CHICAGO POPULAR SCIENCE MONTHLY ADVICE IN BUILDING Popular Science Institute Tells How to Cut 30% Off Your Fuel Bill by Insulating An insulated house is warm in winter, cool in sum- mer and costs one-quarter to one-third less to heat than a similar house without insulation. Before you build or modernize your present home, you will want to have full information on insulation. A 24-page booklet, INSULATION IN BUILDING CONSTRUCTION, gives actual facts and figures as to what insulation will accomplish, tells where it is of greatest value, describes the principal insulating mitterials and shows particular methods of applica- tion. The Engineers of The Institute have prepared this booklet which contains data secured from thousands of architects and builders, as well as university laboratories and Government bureaus. Price 25 cents. Popular Science Institute, 248 Fourth Ave., New York, N. Y. Financial Racketeers (Continued from page 5) by the opportunity to buy sound securi- ties on the monthly payment plan. It is only one of innumerable schemes that are continually being promoted—schemes that come within the law, or nearly within the law—but which end up in loss to innocent people. There is ‘one law, or principle, which will protect any investor against financial loss through crookedness. That is to in- vest only with firms or banks of estab- lished reputation. Robert Hayes thought his firm had an established reputation— it had as far as he was concerned. But it was established on the. thinnest veneer imaginable. It is easy to find out about a legitimate firm. If you do not know them yourself, and if your banker does not know about them it is easy to get their history. There are firms in Wall Street who make it a business to investigate every security sell- ing enterprise. They gather all the facts about new companies. To Help You Get Ahead en Booklets listed below will help every family in laying out a financial plan. They will be sent on request. ‘*How to Build an Independent Income”’ is the title of a new booklet by the F. H. Smith Company which explains conclusively how people of moderate means may obtain financial prosperity. **55 Years of Investment Serv- ice’ describes the history of progress of’ the F. H. Smith Company as well as making an attractive suggestion in first mortgage feal estate bonds. May be obtained by addressing the home office of The F. H. Smith Company, Smith Building, Washington, D. C. The House Behind the Bonds reminds the investor of the importance, not only of studying the investment, but of checking up the banker who offers it. Address: Fidelity Bond & Mort- gage Co., 1188 New York Life Building, Chi- cago, Ill. **The Investment Trust from the Inves- tor’s Viewpoint,”’ presents an explanation of this form of investment in easily understood terms, illustrated with some interesting examples of how the general investment trust will help the man with $100 or more to get ahead. Pub- lished for free distribution by United States Fis- cal Corporation, 50 Broadway, New York. Ask them for Booklet IT. How to Retire in Fifteen’ Years is the story of a safe, sure and definite method of establish- ing an estate and building an independent in- come which will support you the rest of your life on the basis of your present living folios. Write for the booklet to Cochran & McCluer Company, 46 North Dearborn St., Chicago, Ill. How to Get the Things You Want tells how you Can wse insurance as an active part of your rogram for getting ahead financially. Phoenix eae Life Insurance Company, 328 Elm Street, Hartford, Conn., will send you this booklet on request, The Guaranteed Way to Financial Inde- pendence tells how a definite monthly savings oe will bring you financial independence. irite for this booklet to Investors ealicase, 100 North Seventh Street, Minneapolis, Minn. The Making of a Good Investment tells how 614% can be made on investment in First Mortgage Bonds in units of $50, $100, $250, $500 and $1000; how the bonds are protected and how simple it is to purchase them. For a copy of this booklet address United States Mortgage Bond Company, Limited, Detroit, Michigan. Fidelity nds are Guaranteed I BOND * MORTGAGE (0. J.U.MENTEER.President ~ 660 Chemical Bldg., St. Louis 1188 New York Life Bldg., Chicago INCORPORATED 1913 Fill in Coupon for Latest Listings 378 Colorado Nat’! Bank Bldg., Denver MAIL COUPON TO NEAREST BRANCH Name Fidelity Bond and Mortgage Co., Send me, without obligation, list of your latest issues. let, ‘The House Behind the Bonds.” Address Also, your book- City State. traight to the mark ¢@ PPORTUNITY to travel—a col- lege education for your chil- dren—your home—a_ car—these and other pleasures can be yours if you BEGIN NOW on a definite plan of investment. By investing part of your earnings systematically each month, we will unconditionally guarantee you sums from $1,500 and up, in 120 months. $9.45 monthly, pays $1,500—$31.50 monthly, pays $5,000 monthly, pays $10,000. Write for Booklet PS-13 giving further facts, also our financial statement showing ,resources of over $25,000,000. — and INVESTORS SYNDICATE Established 1894 —_— MINNEAPOLIS, MINN. HOME OFFICE: New York Office: 17 East 42nd Street Offices in 51 Principal Cities for 5. 7.

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POPULAR SCIENCE MONTHLY The story of a typewriter that went to war By a War Correspondent was in July, 1916. The comman- der of the British Flying Head- quarters at Saint-Omer took me for a flight over the lines. Holding my Corona between my knees I wrote the first description of the front Coronaisthe W orld’s Champion Portable on_8 Exclusive Points 1. strencTH: The only portable with a rigid one- piece solid aluminum frame. 2. simpLicity: Fewer parts than any other standard-keyboard typewriter. 3. COMPLETENESS: More big-machine features than any other portable typewriter. 4, EASY TO LEARN: Corona design is the result of 20 years’ study of the needs of beginners. 5. WAR SERVICE: 4n unequalled record for dura- bility as the official portable of the Allied Armies. 6. poputarity: As many Coronas have been sold as all other portables combined. 7. DURABILITY: Coronas purchased 20 years ago are still giving satisfactory service. 8. speauty: Graceful in line; exquisitely finished in every detail. CORONA The PORTABLE TYPEWRITER ever typed from the air. During a cruise in a British submarine I typed a com- plete magazine story while we were nos- ing about off Heligoland, a hundred feet beneath the surface. A description of the first Zeppelin raid over London I typed at a shattered window by the light of the fires from incendiary bombs. Throughout my entire period at the front, all my writing was done on my Corona. Because of its portability and dependability, I made it a constant companion. Many a story banged off hot in a front-line dugout would never have been written if I had waited to reach a spot of greater convenience. During my war-time work in Europe I typed an average of 15,000 words a week. In addition to this I typed the manuscript of four books. Yet, in spite of a number of emergency repairs made necessary by violent accidents, my Advance of 18th Inf., rst Div., Oct. 11, 1918. Photo U, 8. Signal Cor ps, Corona was still in highly serviceable condition when I arrived back in New York in 1919. The foregoing is only one of many astonishing Corona stories. You owe it to yourself to drop into a store where typewriters are sold and seewhy Corona is the Champion Portable. The minute you lay eyes on it you will realize why a million people use it—why Roosevelt took one to Africa—why 30,000 Coronas were used in the World War—why more novelists, more newspaper men, more business men, more students in schools and colleges use Corona than all other portables put together. For a small down payment you can take a beautiful new Corona home with you today. Don’t neglect this oppor- tunity. Don’t let another day pass with- out doing something about it. Know now the joy of owning a sturdy, speedys smooth-operating Corona—the Cham- pion Portable Typewriter of the World. An interesting illustrated booklet called “Corona Typewriters,” which de- scribes Corona in detail and contains beautiful illustrations of the new color models, will be sent you upon request, No obligation. Simply mail the coupon below. LC SMITH & CORONA TYPEWRITERS Inc 51 Madison Ave., New York, N. Y. Please send me the free booklet, “Corona Type- writers.” Name Slee Street... City State. sts

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POPULAR SCIENCE MONTHLY Aprit, 1929 Refrigerator or Germ- Breeder? By F. G. PRYOR, Secretary Popular Science Institute of Standards N MANY homes a refrigerator does duty until it gets too small for family requirements, fails to fit satisfac- torily into a new home, or is about ready to fall apart. Almost never is a refrigerator replaced for sanitary reasons, and yet the essential and important thing wrong with most refrigerators is that they do not refrigerate and are not safe containers for perishable foods. This consideration of appearance and forgetfulness of health is wrong. In- efficient refrigeration may be poisoning a family slowly, yet nothing will be done about it until the hox gets crowded or kit- chen appearance is marred by its shabbi- ness. Then the chances are that the new “refrigerator” purchased will be bigger and brighter but not much more efficient than the old when it comes to properly preserving food. Food kept at a temperature above 50°F’. soon decays, though it may be palatable for some time. Bacteria will multiply 130 times, for instance, in a piece of meat kept forty-eight hours at a temperature of 60° I’. In large numbers bacteria are often dangerous though not evident. A test was made with five persons who were all served veal soup in which bacteria had multiplied 1,420 times; the soup tasted all right to every one of them. URPRISINGLY few refrigerators in »_) general use do maintain a temperature of 50° or under—in fact, it is a common oc- currence to find refrigerator temperatures more nearly approaching the mark set for room comfort than for proper food preservation. The way to determine whether food is being kept safely is to place an ordinary house thermometer in the refrigerator for thirty minutes. If the refrigerator is a good one, the temperature will not be higher than 50° F. in any part of the food chamber. Should the temperature exceed that safe- ty limit, the box should be replaced. It is false economy to go on using a leaky cabinet that runs up uselessly high ice bills and spoils food, besides endangering family health. When it comes to selecting a new refrig- erator, something more than lining and trimmings should be considered. Food can be kept safely in a refrigerator of either automatic or ice type providing the particular make selected is efficient. So far as cost goes, it is generally neces- sary to spend more than has been cus- tomary in buying cabinets that never really did refrigerate. However, price is not necessarily a means for measuring merit; Popular Science Institute recently refused to approve a fine-looking $150 refrigerator that was found by test to be rly constructed and most extravagant in ice consumption. In buying an automatic refrigerator, particularly if one of the widely sold makes is selected, there is not as much chance of going wrong. The manufac- turers have had to be careful to use well- insulated and generally well constructed boxes, for a poorly insulated automatic refrigerator would be costly to run since the automatic controls are set for a cer- tain temperature and a great waste of current would occur in keeping the tem- perature of a leaky box up to the set point. However, an efficient refrigerating unit installed in a properly constructed box requires little electric or gas energy and the operating cost is low. Entirely different conditions are en- countered with refrigerators of the ice type. In the first place, no amount of ice will keep a leaky box at the correct tem- perature; the heat leaks in faster than the melting ice can cool it, even though a tremendous amount of ice is melted. And consumer demand in the case of re- frigerators of the ice type is unusual. Unlike the buyer of an automatic re- frigerator, the purchaser of an ice box is not at all concerned about operating its laboratory at New York University, Popular Science Institute has found many good makes. A list of these may be obtained free on request. A booklet containing a full discus- sion of the advantages of various types of refrigerators, together with data on operating cost, precautions in installing, and complete advice on care and up- keep, is available. This 24-page manual, Refrigeration in the Home, costs 25 cents a copy. For the list of approved refrigerators and the booklet, address Popular Science Institute, 250 Fourth Ave., New York, N. Y. [ TESTING refrigerators in A refrigerator that failed to pass the tests, Many so-called re. frigerators are not safe containers for food, When selecting 9 new refrigerator, it pays to consider more than the trimmings, aw? cost; what he wants is a good-looking box whose initial cost is low. Manufacturers must comply with the demand, and the best concerns are obliged to include at least one line of cheap boxes. A well constructed and in- sulated box which will properly refrigerate cannot be built under present conditions for the small amount most buyers are willing to pay. Cost must be cut, how- ever, if the refrigerators are to sell; and the skimping is done where it affects appearance least but efficiency most, since buyers are all-concerned with the first and care not at all about the latter. N BUYING a refrigerator, therefore, one should be prepared first of all to pay enough to get real refrigeration. If the buyer can afford to buy convenience with good refrigeration, he will do well to select an automatic refrigerator. A sur- vey recently made by an impartial organization showed ninety-five percent of the owners of automatic refrigerators to be entirely satisfied. If a refrigerator of the ice type is selected, special inm- quiries should be made as to the amount of insulation—two inches of cork or its equivalent is essential. No matter which type is decided upon make certain that a real refrigerator replaces the old bacteria incubator. Apr FOF

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1» 1929 ting a ator, it ler more ig box h the 3 are ne of id in- zerate itions 'S are how- ffects most, h the atter. efore, all to . 2 jence ell to . sur- artial rcent ators rator 1 in- ount atter rtain 2 old ApRIL, 1929 FOR LIGHTING FIXTURE POPULAR SCIENCE MONTHLY Down like lead went display room costs because of this grainless wood Here is a manufacturer whose sales shot up and whose costs went down when he paneled his showroom with Masonite Presdwood. Scores of others have used this sturdy material to solve a shipping problem, improve a product or cut production costs. You, too, may find, in some phase of your business, an ideal use for Presdwood. A generous free sample will be sent on request. The problem of properly dis- playing their lighting fixtures was a “thorn in the flesh” with Victor S. Pearlman and Com- pany of Chicago, until their architect, Bert C. Hubbard, recommended a showroom pan- eled in Masonite Presdwood. Previously, fixtures were screwed to ordinary plastered walls. Changed displays left unsightly marks on the plaster. Screw holes had to be patched. And frequent redecorating was necessary. DISPLAY PANELS Now all the walls are paneled in Presdwood. A different style of fixture is displayed in each section of the wall. The soft brown tone of the grainless wood panels harmonizes with the walnut finish of the rest of the room and sets off each fixture display to best sales advantage. Presdwood saves decorating cost because it requires neither a rubbed or varnished finish. Although only one-eighth inch thick, this dense, sturdy material holds fixtures weighing up to forty-five pounds, even when ordinary wood screws are used. Old screw holes in Presdwood are easily filled. And when any section shows too many holes it can be removed and a new panel sawed out and put in its place at trivial expense. Better products—Lower costs But the uses of Presdwood are not confined to dis- play room walls nor to any one industry, for in a multitude of manufactured products it is mak- ing things better while it makes them for less. It is used in radio cabinets, tension boards forloudspeakers, show cases, table tops, portable billiard tables, book cases, kit- chen cabinets, china closets and for toys and playhouses. It makes sturdy shipping boxes with ample strength to protect delicate articles. And it makes smooth boxes with no splintering surfaces to dam- age sheer silks or the finest fabrics. Because of its resistance to moisture, it is used for dairy product containers, for outdoor signs that are exposed to the weather and for side panels of motor truck bodies that must stand up underthe hardest usage. Liked by production men Presdwood is easily worked, for it contains no foreign binding material to dull good tools. It is made in four foot by twelve foot boards, either one-eighth inch or three-sixteenths inch thick. It can be punched, die-cut, milled or sawed. And because it lends itself so readily to quantity pro- duction methods, it is becoming as popular with the factory production manager as with the sales executive who specifies it for display rooms. Give Presdwood a trial. It may solve a display or production problem for you as it has for others. A large free sample is yours for the asking. MASONITE CORPORATION Sales Offices: Dept. 724 111 W. Washington St. Chicago, Illinois Mills: Laurel, Mississippi FOR STURDY BOXES asonite PRESDWOOD Made by the makers of MASONITE STRUCTURAL INSULATION FOR PORTABLE BILLIARD TABLES FOR RADIO SPEAKER TENSION BOARDS ©1928, M. F. Co.

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Ow Readus Say- POPULAR SCIENCE MONTHLY APRIL, 1929 , What’s Wrong Here? OU’VE heard the mythical story of the man who consented to work for one cent the first day and double his wages each day, and how there would not be enough money in the world to pay him? Well, did you ever apply the same idea to count your grandfathers? So far as we know everyone has had two grandfathers (and two grandmothers). Each of your grandfathers, in turn, had twe grandfathers, which would be your great-great-grandfathers. Each of them, in turn, had two grandfathers, which would be your great-great-great-great-grandfathers. And so on. I have just been figuring the thing out, multiplying each set of grandfathers by two, as follows: ES are oy ee 0 Your Grandfathers........ he een tt Your Great-Grandfathers............... 4 Your Great-Great-Grandfathers......... 8 Your Great-Great-Great-Great-Grand- CE ee cae hehe esaess 16 Ne ag ae a tea tae dau ata 32 64 128 “The pyramiding figures become appalling. I have carried out the multiplication only thirty-seven times—which, figuring each gen- eration at thirty years, will put us back in time about 1,110 years—and the resulting number is 269,999,730,948 grandfathers! I am sure this number of people never lived on earth at once. History tells us that 6,660 years ago there were comparatively few people. Yet if you figure out the number of your grandfathers. who lived 6,660 years ago, you get a figure with sixty-six units! And sup- pose you should go back 25,000 years—you wouldn't have enough space in this book to write the answer. “In reality there must have been a starting _point when there were only one or two people on earth. But no—we are going the other way. The whole thing is topsy-turvy. Yet there are the figures. I am frank to say I can’t answer the puzzle. What’s your solution?” —W. E. C., _ Kansas City, Mo. Good Target Practice, Too *“T READ with interest the proposal of Prof. William B. Franklin, physicist of the Massa- chusetts Institute of Technology, for the use of ‘smoke rings’ to pre- vent hurricanes. My sug- gestion of a possible means of limiting the de- structive effects of a tornado would be the rapid-fire bombing of it before it reaches cities or towns in its path. This might be done with heavy shell firing, and at least partly break up the force of the ‘twister.’ I should like to hear what others think of this proposal.’’—W. G. B., Stratton, Neb. An Idea, Mr. Guggenheim “IN THE article ‘If You Had Millions to . Spend,’ the overcoming of sleet was listed by Harry F. Guggenheim as one of four funda- mental flyi problems remaining to be solved. I believe I have a practical method of preventing sleet forming on an airplane's wings. The idea is to construct all-metal wings so that hot exhaust gases from the plane’s motors could be carried through pipes into the hollow wing interior, passing out through an opening at the rear of the wing tip. In flight, the air rushing around the wing tip would create a partial vacuum which would suck out the exhaust gases and prevent back pressure.” —R. S. D., Lima, O. Page Jonah re a word of criti- cism of your short article entitled, ‘If Brain Size Counted, the Whale Would Be Smart.’ That is not a new argument. I read about it years ago. I ever contended that the absolute size of the brain determined the intelligence. It is a fact that man’s brain is relatively larger and heavier than that of any other creature and absolutely larger than most of them. Furthermore, the advanced races of mankind have larger brains than the inferior races. Great men have large brains.”"—R. C. C., Jasper, Ala. Try This on the Fourth ms HAVE a younger brother who is greatly interested in building and flying model planes such as are published in your magazine from month to month. During a recent con- versation I jokingly told him to try and develop a plane propelled by a rock- et, my idea having been YF” derived from the recent . g German experiments. ‘// Great was my surprise to find in PopuLar ScrENcE 'e a picture showing German 7) children flying planes 7 whose motive power is furnished by the propel- ling force of rockets. Here is a problem for Danner Bunch and his collaborator Koch. I feel confident that if there is any merit in the idea they could produce such a model. Let’s hear from them!”"—E. W. B., Allentown, Pa. It’s Easy to Build “(CONGRATULATIONS on your ‘modern- istic’ furniture. It is a boon to one who is not very good at making elaborate furniture, and is just what I want. I have made your bookcase, and am now making the modernistic lamp. I have been reading your magazine for some time, and it is far superior to any other magazine I have yet seen.’’—H. R. W., Kings- land, Shrewsbury, England. No Hoodoo Day for Him “(HAT idea, outlined in your editorial, of changing the calendar so that every month will begin on the same day of the week, strikes me as a good one. But I think it would be wiser to start each month and week on Monday in- stead of Sunday. Then the thirteenth of the month will always fall on a Sat- urday instead of on a Friday.” —C. G. P., Gar- field, N. J. don’t think anyone has— Canada Calling “T NOTICE an item in Poputar Scteycg which states that ‘the recent acquirement of additional lines in Kansas and Texas is said to have made the Santa Fe the world’s lo railroad, slightly exceeding its nearest mileage rival, the Southern Pacific System, which has 13,165 miles of track.’ May I remind you that the Canadian National Railways have a total of approximately 22,970 miles of track, with the Canadian Pacific following a close second with about 20,000.”—J. H. M., Halifax, N. §. Was It a Bargain? “TN A recent issue was a description and drawing contributed by one of your sub- scribers for making and installing a dust layer or sprinkler in the ash pit of a heater. I had a plumber install one of these in my heater. The cost of the installa- tion was $10. I would not do without it for 100 times its cost. For many years I have been experimenting with some method of dampen- ing the ashes. The description and drawi referred to seemed to be the most practi and simple of anything I have ever seen. This one item is worth many years’ subscriptions.” —wW. W.C., Washington, D. C Such Ignorance! “T REGRET to inform you that you havea very poor artist. The one I am knocking is the fellow that drew that picture showing a radio enthusiast’s cellar, the one illustrating ‘Making a Television Disk.’ The drawing was all right, but the artist put cobwebs, etc., all over the radio loudspeaker and other accessories on the shelf. No radio bug patient enough to experiment with television leaves a set lie in one place (or together) long enough to accumulate spider webs. And, by the way, aluminum doesn’t crack as the disk on the floor appeared to be.’ —W. L., Paterson, N. J. A Use for Them at Last! “TEADING on a loom is an ancient art. To people taking up this fas- cinating work it will be found a great help to ap- peal to the cross-word puzzle for designs.’’—Le R. O., Ogden, Utah. Easy to Take “‘7OUR index is so divided as to make search of an article delightfully easy.”— T. S. J., Tulsa., Okla. “Your cover is original and distinctively artistic, and the inside is meaty. I am getting wonderful value for my money.”—J. W. F,, Glasgow, Scotland. “T find only one objection to your magazine —it’s so dog-goned interesting I can’t lay it aside till finished.” —W. D. S., Orlando, Fla. 1.

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Scrence uirement tS is said s longest Inileage hich has you that e a total ck, with e second ix, N.S, it it for ve been ampen- irawing ractical n. This tions.” have a 10cking wing a trating lrawing »S, etc., other patient paves a enough \e way, he floor make ” sy. = tively vetting V. F., gazine lay it Fla. APRIL, 1929 SUMNER BLOSSOM Editor VOL. II4, NO. 4 — Prof. Albert Einstein. His theory of relativity, which has been called the greatest single achievement of the human mind, has been ex- tended, by his latest dis- coveries into a_ single new law of the universe. Kinstein’s Topsy- lurvy World By ALDEN P. ARMAGNAC UTSIDE the little printing office in the Prussian Academy of Sci- ence building in Berlin, on a Wednesday afternoon, a young man waited his turn to pay one mark for a little pamphlet to be published that day. He scowled at his watch; he had been there since early morning. The clock struck two. A bundle of papers appeared, and was ripped open. The young man’s eager hand grasped a little six-page leaflet bearing the cryptic legend “Zur KEinheitlichen Feldtheorie—Albert Einstein.” He raced away, bound for a radio office. Working hurriedly with photographic paper and solutions, a corps of experts made a photostatic copy and slapped it on a revolving cylinder. The next in- stant, black and white dots and letters were appearing on a sheet of paper in London. Almost before the Londoner’s machine had stopped revolving, he had his copy of the radio-forwarded picture back on a transmitting cylinder. A sec- ond later “the biggest piece of scientific news” since Isaac Newton turned some pretty philosophy, about a falling apple, into workable laws of gravity, was speed- ing to New York at the rate of 186,000 miles a second. The “news” consisted of twenty math- ematical formule which Prof. Albert Einstein—author of the “relativity” the- ory of time and space that attracted wide attention a few years ago—says are the basic traffic laws of the universe. Briefly, Einstein, a mild-mannered little man with bushy hair and a shy, reserved manner, has apparently accomplished what sci- ence’s leaders have been trying to do for years. He has justified the exceedingly simple idea, despite its enormously complicated mathematical proof, that behind the “gravity” that endows a piledriver with its mighty blow, and the “electricity” that makes a motor whir, lies the same basic force—an all-pervading one which he terms, simply, “the field.” If his the- ories stand the test of trial, they may VW

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What makes the balls swing out when the shaft is spinning (left), and fall together when it stops (right)? Engineers say “centrifugal force’ for the first, and “gravity’’ for the second. But Einstein says they are the same. have revolutionary consequences; per- haps even being the basis of new inven- tions as startling as the radio or the flying machine. ' Yet the average man looking POPULAR SCIENCE MONTHLY pharmacist’s clerk. Neither Faraday himself nor any of his colleagues dreamed then that these theories would result in the dynamo and the electrical wonders of the twentieth century. Another analogy is that of James Clerk Maxwell, the Scot- tish physicist who between 1870 and 1879 published a series of mathematical equa- tions proving that light is made up of electrical vibrations. He little realized, any more than did the German physicist Heinrich Hertz, who ten years later, first applied the equations practically, that they would pave the way to radio and television. Since the publication of the new manu- script, newspapers throughout the world Apri, 1999 but not the same. In his work Binet: really finds a long-sought coun between gravity and electricity, and he theory explains the fact that there jg insulator for the second but none for the first. Mc: technical ‘men confine their comments to less spectacular pre. dictions. Prof. Thomas H. Gornwall of Columbia University, says that it js quite probable that we can find as a result of Finstein’s new work information as to the nature of light, and that we will be able to account for the behavior of vacuym tubes and radioactivity, to the end that better tubes may designed. Dr Charles E. St. John, of the at the six-page book entitled “On a Unified Field Theory” would be bewildered at the mass of mathematical hieroglyphics. He need not feel ashamed, for learned professors of science and mathematics confess themselves equally muddled. In the opin- ion of one of Professor Ein- stein’s colleagues— Prof. Freundlich, head of the Einstein Institute of Potsdam—only a dozen men in the world, today, are able fully to comprehend the new theory. T TOOK Prof. Einstein ten years to write his latest six- page book—a little more than half a page a year. It contains symbols that many skilled stu- || dents of higher mathematics have never seen. To describe the complicated behavior of electricity and gravity, Einstein availed himself of strange char- acters only recently invented by Herr Weitzenbock, another great mathematician. He even invented a whole system of geometry all his own. Despite its technicalities, the book recently placed on sale at about twenty-four cents a copy I HIS queer combination of letters and symbols is the law of the universe, as expressed in Einstein’s new mathe- matical formula. Only the world’s most brilliant mathe- maticians are able to comprehend its meaning; yet it explains in one and the | same breath the mysterious electricity of the dynamo and the gravity of the pile driver. Even the semicolons between the letters have a complex meaning of their own in an expression of a universal law. Mr. Armagnac’s interesting article is in no wise an attempt at technical ex- planation; simply an understandable account of what Einstein’s latest dis- covery means to science and to you and me.—The Editor. — Mount Wilson Observatory || staff, in California, sees it as || “the first great weapon by | which scientists may attack the mysteries of gravitation.” Prof. Max von Laue, of the Prussian Academy, says simply that “Einstein will go down in his. tory as one of the greatest scien- tists of all times, provided his theory is correct.” Meanwhile Einstein himself declines to discuss his newest triumph for fear of seeming to seek self-advertisement. “I cannot understand why all this noise is being made over my little manuscript,” he says, “T do not look for publicity; on the contrary, I do not want it.” | The man who caused such || world-wide discussion lives with || his wife and daughter in a small | third-floor flat in Berlin. His study, apart from the living | quarters, reeks with tobacco || smoke. He likes to play the || fiddle—and plays it well, accord- | ing to his good friend Fritz ‘| Kreisler, the great violinist. He enjoys a good movie show, and is frequently seen at Berlin theaters. Anyone who e to find the author of the rela- is a “best seller,” to a degree un- paralleled in scientific litera- ture. Hopelessly swamped with orders, the overworked printing shop of the Prussian Academy of Sciences reflects the amazing interest of laymen as well as scientists in its disclosures. The linking of electricity and gravity was the one step needed to extend the famous Einstein theory of relativity to account for all the happenings in the universe. So fraught with significance is the newest discovery that it is almost irapossible even for Einstein himself to say, hastily, where it will lead. New and better tubes for your radio are apparently one possibility. X-rays of unheard-of power are another. We may co things with radium that we never did before—mastering, incidentally, in new ways artificial light and radiant heat. These are reasonable guesses, made by men of science, about a few immediate consequences. However, no man living today can foresee in detail the far-reaching possibil- ities of the theory. Scientists contrast Einstein’s newest manuscript with the theories produced from a London cellar in 1831 by Michael Faraday, a British have published thousands of words about it. Einstein had discovered that electric- ity and gravity are the same, they said. Suggestions were made that since we already know how to insulate against electric currents we might now insulate against gravity. A professor in an East- ern university gravely remarked that we might even learn how to step out of win- dows without falling! Others pointed out that we might make airplanes fly without wings, and navigate to other planets, all by means of the marvelous insulator against gravity that might result from the new theory. But Einstein does not say that electricity and gravity are the same, any more than an Englishman and a Chinaman are the same kind of men, though both have two ears, two eyes, and a nose; both are born, marry, live, and die in pretty much the same way. They are similar, tivity and the field theories a cold-blooded, machinelike type of scientist is due for a surprise. He is essentially human. Born of German Jewish parents in 1879, his career of just fifty years is one almost without parallel in the world of science. His original theory of relativity, which at- tained world-wide prominence ten years Awe peg © OS Ejinstein’s explanation of gravity and how you can manufacture it yourself. The man will stick to the speeding ball, representing the earth, as long as the falling weight accelerates it fast enough. In other words, the ball pushes up on his feet and holds him to it.

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result of | as to the l be able Mee €nd that ed. Dr, of the ervatory eS It as ‘pon by tack the Prof, Prussian ly that 1 In his. st scien. ided his himself newest ming to id why de over he says, city; on ant it.” d such es with ries a e type He is 1 1879, almost rience, ich at- years me ture it enting ough, to it. aprit, 1929 and won him a Nobel prize in ysis in 1921, has been called test single achievement of the human mind. It was set forth in its essentials in a “book” of three es. According to a bib- jiography compiled not long ago Prof. Morris Lecot, of the University of Louvain, no less than 3.775 books have been written to explain it! HEN the Royal Society of Wondon gave its approval to this remarkable theory, in November, 1919, it burst practi- cally unannounced upon the world. Such matters as whether space is curved, whether there is a mys- terious fourth dimension, immedi- ately became topics of parlor con- yersation. Only a few college pro- fessors remembered that away back in 1905 Einstein, then a young man of twenty-seven, had _ told all about his theory, in a little per contributed to the Annalen der Physik. It had taken fifteen ears for it to receive the Royal Society’s approval. In the first place, young Ein- stein had had the temerity to challenge the laws of gravity laid down by Isaac Newton in 1687. his new law, starlight ‘would be found to be bent in passing the sun, so that stars near the sun would be shifted in their apparent position a consider- able amount. Moreover, Ein- stein calculated and announced exactly how much they would be shifted. An eclipse of the sun was scheduled to occur on May 29, 1919, at which it would be possible to make exceedingly accurate measure- ments of stars:around the sun. Two expeditions of British In a view like this, you may think you are looking at skyscrapers, says Prof. Einstein, but actually you see only three-dimensional “shadows’’ of the real thing. astronomers photographed the eclipse; one from an island on Newton’s laws were good enough for ordinary mortals, Einstein said; but when applied on such gigantic scale as astronomers use, they didn’t exactly fit the facts. For illustration, Einstein pointed to the erratic motion of our neighbor planet, Mercury. Every so often it failed to keep an appointment in celestial space that astronomers, figuring its course by Newton’s laws, had pre- dicted for it—and showed up somewhere else instead, greatly to their consterna- tion. What Einstein proposed was a new law of gravity, retaining all of Newton’s but adding just one slight correction. The new law explained why Mercury wabbled from its course. But critics claimed Einstein’s figures were “padded” to give the right result which, of course, was known in advance in Mercury’s case. So Einstein made a bold statement, which delighted them. He prophesied that, in accordance with the west coast of Africa, and another at Sobral, in Brazil. When the plates of both expeditions were developed, they showed to the amaze- ment of the astronomers a shifting of the stars that not only confirmed Einstein’s theory but almost exactly agreed with his calculated figures. Then the world heard about Einstein. Columns upon columns, in newspapers and magazines, were used to explain that only seven men—sometimes the figure was set at twelve, or four—could under- stand the theory. Attempts were made to clarify it for the lay reader. But even 8,775 books, not to mention an ambitious motion picture film replete. with dia- grams, hardly sufficed to make it all clear. The Relativity Theory, which with the addition of Einstein’s latest work becomes an explanation and cor- relation of everything from space to electricity, is as mind-staggering as ever with its astounding notions. And the controversy among scientists that it 19 Uur artist’s por- trayal of how things might look if we could see them in Ein- stein’s queer four-dimensional world, compared with how they appear in three dimensions. started is still raging, though certain parts of the theory are now generally accepted as true. Is there a mysterious fourth dimension, of which Einstein so glibly speaks? We speak of things as having length, breadth and thickness—those are our three ways of measuring. Now Einstein tells us that we have only partly described an object; that time is the fourth dimension. In other words, the time of an object’s ex- istence must be stated also if that object is to be described completely. All four ‘“‘dimensions,” he adds, are so closely in- terwoven that they depend upon each other. He can trace and express in mathe- matical terms the connection, measured in latitude, longitude, altitude, and time, between such apparently unrelated things as the chair in which you are sitting, the Battle of Waterloo, the moon, and next Tuesday. INSTEIN plays hob with geometry as we know it. A straight line is no longer the shortest distance between two points, he says; instead, the shortest way is a curve. All space is warped, and curves back upon itself. If you were to fire yourself, astride a projectile, straight out into space, in a few million years you would return to your starting point. Further, he explains, a fall from a height is not the result of the pull of gravity— but of the earth coming up and hitting the falling object. Things shrink when they move rapidly, . Einstein says. A train speeding at sixty miles an hour is shorter than a train standing still. But a solid six-foot rod shot forward at the speed of 160,000 miles a second — (Continued on page 133)

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20 « JPULAR SCIENCE MONTHLY APRIL, 1999 h! —They’re Filming Talkies!” An Actor Tells from His Own Experiences Just What Goes on in the New Sound Studios By eserring ERE SCENE IS ENACTED aie | 4 y a CONSTRUCTED TO | i AND OFF AS SOUND TRACK 7 ' APPARATUS FOR’ i, | WALLS ESPECIALLY MICROPHONES Garomaene | ay, / ABSORB SOUND el he ORME Lien ffi AND PREVENT DISK RECORD! || gauasgeeey ee Al ECHOES ERS FOR.) ‘= | / , \Ad | “PLAY BACK = RAs 4 i . ‘ nt Ty) r fl be ek nee if j j MONITOR REGULATES ir } _ SOUND VOLUME AND k- .OPERATES MICROPHONE ti} SWITCHES ; | , fr- i] Shi is / | F CAMERA | } THS— Arrangement of typical SOUND-PROOFED || | talking movie studio FLOOR COVERED AND MOUNTED ON . Witt FELT TO PNEUMATIC WHEE! showing apparatus for DEADEN FOOTSTEPS recording scenes and sounds simultaneously, Note precautions to kill all foreign noises, ’*M IN the “talkies” now! After five years as a Broadway stage actor, I have begun work in - my first talking movie at the Para- mount studios near New York City. On my first morning there, I was ushered into a strange and bewildering world where shadows are made audible, words and music photographed; where sights and sounds are printed, canned, and shipped to the four points of the com- pass! For the first time in years, I suffered stage fright when I stood upon the “stage.” When I use this word, you shouldn’t imagine the raised platform of the theater. In movie parlance, a “stage” is a large, high-ceilinged room where a “set” has been arranged for a scene to be played and photographed. It was strangely still here; I heard no voices, no whir of cameras; nothing! I stretched my hand toward a door knob and a burly individual, who had been quietly eyeing me, grabbed my arm. “Don’t move! Stay where you are!” he whispered. “But,” I protested. “S-h-h! Don’t talk! *shooting’!” For a minute or two I stood where he halted me, gazing at a blank wall and a door. Then we were joined by an assistant director whom I had met before. The latter smiled, but immediately put a fin- ger to his lips to forestall my greeting. The silence was oppres- sive, uncanny. One scarcely dared to breathe. Suddenly, a loud, long ring from an electric bell startled me. In- stantly, a thousand-and-one noises assailed my ears. The door was flung open with « bang. Every- where at once, people called to They're The monitor, master “‘organist’’ of the “talkies.” ates the microphones and controls volume of sound and tone. each other, walked about, talked, coughed. Machines hummed. A bedlam of ham- mering, sawing, planing, and scraping seemed to have broken loose and the blare of a jazz band could be heard through the din. ‘One long ring,”’ the assistant director explained, “is the signal that a rehearsal or the actual ‘shooting’ of a scene has ended and that normal activities may be resumed. When they start rehearsing or filming a scene, the signal is three rings, which means all must be quiet. “You see, in making ‘talkies’ we have a double job. Not only must we get sounds into the pictures, but we must also keep out sounds that don’t belong there. I never knew how many senseless noises there can be until we began mak- ing ‘talkies.’ Now, let’s go in and I'll show you the stage.” I was surprised, even a little disap- pointed. I had expected to see many He oper- intricate and mysterious looking ma- chines and devices, but all that seemed to distinguish the place from an ordinary movie studio were two or three micro- phones suspended from the ceiling. “They are condenser microphones, one of the types used in radio broadcasting,” said my guide. ““They usually hang over- head as the actors talk, just beyond the range of the camera lens. In making ‘talkies,’ the microphone is of equal im- portance to the camera. A ‘mike’ is like a small-town gossip—it hears and repeats everything. That’s the reason for the bell signals and the enforced silences.” LOOKED around. The “stage” was a room measuring about forty by ninety feet. The particular scene set up in it rep- resented a well-appointed private office. “Outside of those microphones,” I remarked, “I don’t see anything out of the ordinary here.” The assistant director smiled. “‘There’s plenty!” he said. “For” example, this room has been made ~ as soundproof as possible by build- ing terra cotta tile walls with air spaces between. ° The doors -are double. Monk’s cloth drapes are hung about to deaden echoes and reverberations. Also, the inside of the walls are treated with sound- absorbing material. Now look at the cameras.” I observed. that these machines —three of them to “shoot” the scene simultaneously from as many different angles—were inclosed im thick-walled booths, like padded cells. ““What’s the idea?” I asked. “To muffle their grinding, of course.” The booths had three padded walls and a fourth of plate glass Rec are

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L, 1929 19 Apnit, 1929 through which the cameras were pointed. These * ‘cells” move on wheels with ic tires. sy friend pointed out that the mary Kleig lights had been re- by noiseless lamps, also that the floor Was covered with thick, gray felt that muffled every step. Even the “office” desks were overlaid with thick Ree. to prevent them from acting as sounding boards to the actors’ voices,” my guide explained. Then, picking up a chair, he added: “4{70U see, each chair leg has felt tacked underneath to deaden sound in case it’s moved around.” I had noticed, on a mezzanine over- looking the studio lengthwise, two rooms with large windows through which, now anc then, I could see men who obviously were surveying the stage. One of these rooms, the assistant director volun- tered, is the “monitor room”; the other the “sound room.” Sounds caught by the stage micro- phones are carried to the monitor room by _ wire. Here an operator, known as the monitor, uses a potentiometer, a device by which electrical voltage can be varied, to control the volume of sound trans- mitted. Through a loud- speaker, he hears every word or noise on the stage, and it is his task to regulate sounds to make them nat- ural From the monitor room, the sound is carried to an amplifier, an instru- ment similar to the audio amplifier end of your radio set, which increases its strength several thousand **Shooting”’ signals orders by pressing buttons. beside him, and standing near by are the sound experts. Camera men may be seen behind plate glass windows. Recording isachine, in which translated sounds are taken as lights and shadows on the film. POPULAR SCIENCE MONTHLY times; thence to the sound room, where it is recorded. By this time, the stage had filled with people. “Now watch closely,” said my guide. “They are going to have a sound re- hearsal. You understand, of course, that a scene must sound absolutely right be- fore we can afford to reproduce it in a theater. For that reason, sound record- ing here is done by two methods—on wax disks like phonograph records, and on film. We use the disk method only for rehearsals. It permits of instant repro- duction, which we call the ‘play back.’ There is another way of making ‘talkies’ that uses the disk method not only for rehearsals, but also for final recording and screen presentation. “During the play back, the director, the sound expert in charge of making the ‘talkie,’ and the actors can criticize the a talking movie. The director, seated, The script girl sits sound values of a scene. Not until everybody concerned feels that the scene sounds just right is it ‘shot’ for final reproduction. But you will see for yourself.” The director sat on a camp chair near one of the cameras. Beside him stood the sound expert. I noticed he was in almost constant telephonic com- munication with the monitor. The actors took their places. “Silence!” the director com- manded. He pushed a button on a little control box beside his chair to signal the sound department that he was ready. In answer, a green indicator lighted on his box. “Green light!” he called. Everybody stopped talking. The recording equipment was adjusted. Then a red flash appeared on the little control box—the signal that the sound department was “all set” for the rehearsal. The director again pushed a button and three long, loud rings of the electric bell pealed through the plant. The famous three rings! Everything in the plant stopped dead. Norman Foster, 21 Disk recording ma- chines used for re- producing sound rehearsals. The disks on turntables receive the sound impression, as in phono- graph recording. Glass jars hold wax shavings from record. The sound rehearsal was on. The hero sat behind the desk in his office. A young woman entered and, in a short dialogue, gave the man her tele- phone number. This he jotted down on the cor- ner of a news- paper.Exit young woman. A man entered. During their brief talk the hero tore off the numbered bit of paper and put it in his vest pocket. Exit former Broadway stage actor, who in this article tells what he man caller. found behind the scenes in End of scene. a “talking movie’’ studio. One bell! All activity and noise was immediately resumed. “That seemed fine to me,” said the director. Then, to the sound expert: “How did it strike you?” “Sounded O. K. to me.” “Well,” said the director, “let’s have a play back.” HE sound man phoned to the mon- itor room; then, with the director and actors, left the stage to take chairs outside. All eyes turned to a huge loud- speaker protruding from the wall beside the monitor room. A buzz. “Silence, ladies and gentle- men,” cautioned the director. ‘“‘They’ll give us the play back on this.” A rasping sound like static over your radio. Then—“Good morning, Mr. Snell.” It was the voice of the young woman in the (Continued on page 170)

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8 POPULAR SCIENCE MONTHLY Apri, 1929 lanning a 44-Mile Tunnel! How Engineers, Deep in the Earth, Aim Gigantic Tubes at an Invisible Bull’s-Eye and Make Them Hit the Mark EARLY a hun- dred feet below the East River, at Fifty-Third Street, New York City, recently there took place an amazing example of engineering skill. Months before, workmen had started on opposite sides of the river, burrowing toward each other, build- ing a new subway tun- nel. When the bores met, the machinery in one passage pushed into the other like a thread entering the eye of a needle. The sixteen-foot openings, «after more than a mile of blind, un- derground digging, met within one fifth of an inch of perfect align- ment! About the same time, in the Cascade Mountains of the State of Washington, a blast “ holed through” the two halves of the new Great Northern Railway tunnel, longest on the Western Hemisphere. Gangs, cutting from opposite sides of a mountain, had penetrated nearly eight miles of solid granite. Three thousand . They feet below the peak the bores met missed a perfect joining by only seven inches. A supreme test of engineering skill in tunnel guidance will be afforded if the often-discussed tube under the English Channel is actually undertaken, as now seems likely. The latest plan calls for a forty-four-mile tunnel, entering the ground eleven miles from the English seacoast near Dover, burrowing through the chalk of the channel bed, and coming up nine miles inland between Calais and Boulogne on the French side. Such a tunnel, costing $150,000,- 000, would allow a broad gage ra'l- way to lead directly from London to Paris. It would be nearly four times as long as the longest tube now in existence, the Simplon Tunnel of the Alps, which is slightly more than twelve miles in length. PLOWMAN guides his fur- row by driving toward a tree or stake on the other side of the field. A surveyor lays out a line by taking bearings from land- marks on the earth’s surface. But a tunnel engineer works deep in London crowds viewing a model of the proposed 44-mile tunnel under the English channel. The immense tube, which would cost $150,000,000, would link London and Paris by direct railway. By GEORGE LEE DOWD, JR. the earth, hedged in by narrow Tunnels under English Channel and Strait of I Gibraltar would join it is England with Africa. Some years ago, in a large city on the Great Lakes, that very thing happened. Inexperj. enced city engineers started a long water supply tunnel at opposite ends. When they thought the passages were on the point of meeting, they had an expert check the work. Ite discovered that the two tunnels would miss by 275 feet! The in- sertion of an “S” curve saved the day. One of the hardest of the many exacting prob- lems of tunnel construc. tion is “steering” the passage to an unseen point far ahead. How accomplished was explained to me by the two men who walls that confuse the sense of direction, his horizon limited to a few feet. Yet, he dare not get off the line a hairbreadth, for a tiny angle of error, at the end of a mile of digging, may cause the bores to miss each other as cleanly as trains passing on parallel tracks. a 105 a HOLD ee kel ee x PLAGE PLATFORM FOR be a WIDE ba a (COMPLETE we) heel # » "a A 4 " Oe , td TRANSIT IN Lo rs MAKING SIGHTS had most to do with “hitting the bull’s- eye” in the latest East River tube. They are S.H. Coombe and W. R. Barry, New York City engineers. S THE first step in that job sur- veyors laid off the course of the tunnel on the surface of the earth, as they would lay off the line of a road. The problem was to transfer this " cole 1onmeey enowet cn s - BTANDS ON TOP OF AIR PLOCK TO SiGHT THROUGH TRANSIT i AP BULKHEAD iN END OF COMPRESSED AiR . 2 CHAMBER ~— EMERGENCY + AIR LOCK \ WIRE MARFEING LINE OFT eu Gn woe if ; GGEO uP) , AIRLOCK FOR MEN cd DOGR CLOSES AND PRESSURE INSIDE S RAISED — “ i ~ ie waten Pome : DRAWS OFF WATER IF \ 'T ACCUMULATES AT ~ BOTTO! Interior of the new transit tube under the East River, New York City, showing the methods of alignment and construction. line underground, working at both ends of the tunnel. A shaft, twenty- four feet in diameter, with ils opening bisected by the line, was blasted in the rock of each river bank to the depth of the tunnel at that point. Plumb bobs sus- pended from steel wires were lowered to the bottom of the shaft from positions on the line at each side of the opening. The align- ment engineer, taking a position in a cavern hollowed out at the bottom of the shaft behind the landward wire, sighted through his transit telescope until the two wires, like sights on a rifle, were in line. A third wire, directly in line with these two, was estab- lished at a point a hundred feet ahead (Continued on page 141) \

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RIL, 1929 a]! igo, in a e Great Ty thing hexperi- igineers & water Opposite n they Passages point of had an he work, that the ardest of ing prob- construc- ng” the n unseen ad. How mplished d to me men who do with e bull’s- e latest Tr tube. e S. H. | W. R. vy York rs. irst step job sur- off the e tunnel e of the 'y would ine of a problem ‘fer this sround, oth ends twenty- with its ine, was ch river e tunnel obs sus- os were he shaft at each e align- position _ at the ind the through the two le, were ectly in ; estab- red feet age 141) Apail, 1929 POPULAR SCIENCE MONTHLY Capt. George Fried, operating compass that traced the sinking Florida. HILE a sixty-mile gale lashed the Atlantic into shifting moun- tainous seas, thirty-two men, 700 miles off the Virginia Capes, clung to the rail of the sinking freighter Florida. For days it had drifted with the wind, rudder broken, decks awash, rails coated with ice. No human being, not even the men on board, knew the vessel’s position. The log book and instruments had been swept overboard. The radio operator, Nunzio di Gangi, sending his frantic SOS, was giving a position 150 miles away, the last observed. Two near-by steamers, rush- ing to answer the call, arrived at the posi- tion indicated and found only a waste of tumbling water. They proceeded on their courses. Somewhere, lost on the ocean, was the sinking ship, calling for help. Three hundred and fifty miles to the north, the liner America was buffeting its way toward New York under the com- mand of Captain George Fried, hero of. the Antinoe rescue three years before. He heard the call and with racing engines turned south. The events that followed, ending in the rescue of all thirty-two men, form an epic of human heroism and skill- ful navigation that is still fresh in mind. But more than that, they reveal the un- canny ability of a few inches of magic wire—the pointer of a radio compass. Captain Fried proclaimed this instrument the mechanical hero of the rescue. “We found the Florida,” he said, “solely by use of the radio compass.” The two vessels that were forced to give up the search were not equipped with such compasses. They could only go to the spot indicated in the call for help. But, on the America, the silent, infallible finger of wire on the compass pointed to the actual source of the radioed distress signals 150 miles to the northeast of the reported position. For sixty-one hours the America’s chief radio operator, Nelson Smith, a veteran of Nelson Smith, the America’s chief radio operator. For sixty-one hours he stood at the compass, tracing the lost vessel. the Antinoe rescue, bent over the instrument tracking the Florida’s weakening signals to their source. Until, guided by the unseen finger of wireless, the liner arrived in time for Chief Officer Harry Man- ning and eight of the crew to res- cue the men of the Florida when the life of the foundering vessel ap- peared a matter of minutes. Just three years before to the day, a similar instrument had led Captain Fried, then master of the President Roosevelt, to the sinking British steamer, the Antinoe, which had drifted 100 miles from its re- ported position. After battling a terrific storm for three days, he saved the crew of twenty-four men. From the beginning, the radio compass has been associated with saving human life. It was invent- ed during the war, in 1915, by Frederick A. Kolster, American radio pioneer, and used on trans- port ships to detect enemy sub- marines by pointing in the direction from which their code signals came. The operation of the compass is ce 23 Sry A Machine That Makes Heroes How the Radio Compass Found the Florida and Defeated Death at Sea By‘H. C. DAVIS the aerial in respect to the direction from which the radio waves are being broadcast. When it is edgewise to the direction of the source, the volume is greatest; when the opening of the loop faces the source, the volume is least. The loop aerial, or receiving coil, of the compass is installed on the roof of the pilot house, protected by an insulated housing, within which the loop revolves on ball bearings. A shaft running down through the pilot house roof connects the loop with the main case of the compass, containing an (Continued on page 187) SECOND AERIAL HOLDING Dt FINDING WIRE | 3 EIGHT-TUBE COMPARTMENT FOR ne ; SET. EARPHONES ~ BINNACLE based upon the fact, known to every owner of a loop aerial radio set, that the strength of signals depends upon the position of. Design and operation of the radio compass. Direc- tion of signals received on the radio set below is de- termined by variations in their strength as the loor aerial above the roof of the pilot house is turned.

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24 POPULAR SCIENCE MONTHLY Captain George H. Wilkins. On his first Ant- arctic flight he discovered Graham Land to be an island, changing map of the world. YING into the Antarctic, over territory no one has ever seen before, explorers, with the latest aerial equipment, are heading into a land of mysteries. How much is unknown about the Antarctic and how much can be learned by a single flight over its frozen waste was illustrated recently by Capt. George H. Wilkins, the daring Australian who also flew over the North Pole from Alaska to Spitsbergen in 1928. On his first hop from his Deception Island base, he discovered that Graham Land is not a peninsula attached to the Antarctic Continent, but an island, thus upsetting the ideas of three quarters of a century. Other mysteries of this, the least known part of the earth, undoubt- edly will be solved by Commander Richard E. Byrd and his expedition of eighty men, who even now are making fights of discovery into the interior from a base on the Bay of Whales. On his first long flight recently with Pilots Bernt Balchen and Harold June, Byrd viewed and mapped some 10,000 square miles of King Edward VII land, hitherto unex- plored. In a five-hour journey they dis- covered a new island and fourteen moun- tain peaks. Exploration has barely opened the door of this frozen land lying at the bottom of the world. Four million six hundred thousand square miles of its area, it is estimated, remain a blank spot on the map. Two men have reached the South Pole on foot. Captain Roald Amundsen, the Norwegian, who was lost in the Arctic last year, discovered it on December 14, 1911. The English explorer, Captain Robert F. Scott, arrived on the spot a month later, meeting his death on the return journey. They started from opposite sides of Ross Sea, an indentation in the land directly south of New Zealand. A. large portion of the explored area of the continent is bounded by their converging trails. This known area, shaded, is like a narrow slice cut from a huge white cake. The vast unexplored portion is enveloped with ice and with mystery. One fact concerning the region around a esi ? Se O™.-— x / RL Se \ 0; ee pote §/ ee ! CG; eae / { Me} \, pe ee: “4 .. a See vas . +. See \ PS bes i Ges j + / eS LA 3 o> °° ¢ £4 ss .* x ino Ee. x Vy o "Sciak Ds ¥ 1X 3 ; "ARGS 8 Rees sees ; t Fe: 7 : * ‘ ve gah \ a \ iis ". oe ~, % te a EDWIN W. TEALE the southern pole has ‘been determined. It is the world’s mightiest refrigerator. Nowhere else on earth is there so much ice. It covers all the land and reaches out in pack ice beyond the limits of the Antarctic Circle. Imagine one solid piece of ice as large as the United States and Mexico combined! If, like Commander Byrd, you were to approach this relic of the Ice Age, you would penetrate first a belt of huge float- ing icebergs. Then you would enter a zone of grinding pack ice, covering the sea like a gigantic jig-saw puzzle. When your ship had battered its way through, you would find yourself at the great ice barrier of the Antarctic. Sheer precipices, gleaming white, would tower above you, sometimes 250 feet high. This tremendous wall of ice is believed to encircle prac- tically the entire Antarctic continent. One of the few known breaks in it is at the Bay of Whales, where Commander Byrd Met 4 Se me o - 2: 4 B PROPOSED “I dy ( gDASE OF JEFFREY Bae ae % @EXPEDITION TO MAP BOUNDARIES. = g THE ANDES RANGE QUEEN Mal ee 22... RANGE \ * ,RourTe PROPOSED BY . @VILKINS TO DETERMINE baae CONTOUR OF THIS © EGIO has established his permanent base. You can best understand the topog- raphy of the circular continent within this wall by imagining a great white disk wheel. Beyond the ice barrier, the land slopes upward for 400 miles until it reaches a plateau nearly two miles high, standing like the hub of the wheel and containing the South Pole. The diameter of this plateau “hub” is thought to be 800 miles; that of the continent “wheel” from 1,200 to 1,600 miles. LL approaches to the Pole have been made from the Ross Sea side. If Byrd’s planes, carrying automatic cam- eras that pholograph an eight-mile-wide strip of the territory below, fly over the Pole, as planned at this writing, and circle the plateau beyond, the developed film will answer many questions about the character of this lofty plain. How will explorers, flying over an end- E STEN THEORETICAL CONTINUATION OF 2 Te KING EDWARD OS™ LAND ———~" Pe a ae ee ee an iin, ae J Rt | a ei ee: |S i

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UNDARIES. STEER Sod =N ATION OF. ge , base. topog- within ite disk 1e land ntil it s high, el and ameter to be wheel” » been e. If > cam- e-wide er the , and eloped about n end- mange

4 dictiestteds i ae : - « : "aa ar - PNG HARKOM | BLATEAU REacte p SCOTT REACHED 1"! POLE JAN. 18,1912 ¢ , HACKLETON ~ JAN.9,1909 scoTTs ROUTETO POLE Be FD MEMURDO STR. less sheet of ice at a hundred miles an hour, know when they reach the Pole? A delicate instrument, known as a bubble sextant, will tell them. This is like an ordinary sextant, such as mariners use to discover their position by determining the angle of the sun above the horizon, except that a bubble level, similar to the common carpenter’s level, takes the place of the horizon. As the plane flies toward the Pole, continual observations will be made with this sextant. Each time the angular altitude of the sun above the horizontal plane is measured, it will be compared with the value the altitude of the sun would have at the instant of observation, if the observer were located at the Pole itself, as stated in the Nautical Almanac published by the U. S. Naval Observatory. By making a succession of measurements of the sun along a single meridian, for all meridians of longitude converge at the ~ BYRD PLANS A MOST ~ eS COMPREHENSIVE SURVEY OF THIS TERRITORY WITH - BASES EVERY |OOMILES © AS CENTERS FOR CIRCLING FLIGHTS NPS =X »~ MAGNETIC PO POPULAR SCIENCE MONTHLY

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“SAKAISER 5 \W WILHELM I LAND <_< Antarctica, the world’s greatest re- frigerator. It holds 4,600,000 square miles of unexplored land. The map shows Byrd and Wilkins airplane expeditions, and routes of previous explorers. Arrow points to South Pole. South Pole, the navigator will arrive at a point where the altitude he gets on his sextant is that which the Nautical Al- manac tells him should be at the Pole. A sextant camera has recently been in- vented which photographs the sun and automatically keeps a record of the posi- tion on the film each time the shutter is snapped. It will enable flying explorers to keep a record of their course and to prove they reached the Pole. N THE interior of the Antarctic, science believes there is no life. There is no food in the great refrigerator. Dur- ing the six months night, the temperature descends to eighty degrees F’. below zero, 112 degrees below freezing, and even in the hottest days of summer, when the sun blazes for twenty-four hours a day, it never rises above zero. So, it is thought, no seed can sprout, and where there is no vegetable life, animals cannot exist. Commander Richard E. Byrd. From his base on the Bay of Whales, he is making flights of discovery into regions never seen by men. Because there is no hunting, the Ant- arctic contains no Eskimos. Only on the fringes of this desolate land of gleaming ice and wind-blown snow are there signs of life. Snow pertels and skua gulls appear for a few weeks in summer, living on sea animals. Byrd and his comrades encountered penguins—queer, flightless birds—standing in groups like soldiers at attention on the ice. These birds remain the year around, laying their eggs in the snow. Whales, fish, and seals are found in Ross Sea. One reason the Bay of Whales is most often chosen for a base by explorers is that there seals pro- vide a sure food supply for the dogs. HE Antarctic is ‘The Home of the Blizzard.” A dead calm may become a shrieking, forty-mile-an-hour gale in two minutes. A clear sky may be filled with blinding, wind-driven snow in the same period of time. This tigerlike pounce with which the Antarctic blizzard de- scends is duplicated nowhere else. Ninety- mile winds are common and blizzard gusts may reach 150 miles an hour. The average summer temperature at the South Pole is given as nineteen degrees below zero. In winter, it is the coldest spot on earth. A subtle connection between the climate of the Antarctic and that of half the world is believed to exist. Meteor- ologists have observed that a severe win- ter in the South Orkney Islands, near the Antarctic Circle, means a drought three and a half years later in the Argentine wheat belt, while a mild winter results in abundant rains and a fine crop in the South American country after a similar time interval. They also link this reservoir of winds at the bottom of the globe with the monsoons of India and believe it has much to do with the height of the flood waters of the Nile in Egypt. When meteorologists of the Byrd expedition return with data covering months and perhaps years, half the world may know important facts about how its weather is formed. (Continued on page 169)

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POPULAR SCIENCE. MONTHLY Robert S. Murray cracks safes for an honest living. Glimpses of People Worth Knowing Thomas D, Camp bell raises wheat ECENTLY newspapers published a story of a “chinless” young man who had been provided with a “strong” face by a bone-graft- ing operation. A piece of his shin bone had been transplanted to his lower jaw. The patient reported that, soon after the opération, he had obtained a job which he had been unable to get before because 2 the impression created by his receding chin. The surgeon who gave the young chap a new face, a new “character,” and a new job was Dr. Fred Houdlett Albee, pro- fessor of Orthopedic Surgery at the New York Post Graduate Medical School. He is the inventor of a comparatively simple little instrument that has come to be known as “Dr. Albee’s bone mill.” With its aid, thousands shattered by the World War or injured in accidents have been given new bones for those lost; number- less cripples have been restored to normal and useful lives, and hundreds of hunch- backed children have been made straight, strong, and happy. In common with other far-reaching inventions, the ori- gin of the Albee bone mill was almost in- credibly casual. When the famous surgeon was a boy of ten, living on a farm in Maine, he amused himself one day by making a toy buzz saw out of an old piece of zinc and fitting up a crude turbine to run it by the power of a brook that ran through the fields near his home. The saw would not cut through wood, so the boy used turnips for “‘lumber.” Twenty years later, the pathetic plight of hunchbacked children made Dr. Albee remember the small make-believe saw- mill. Medical science already knew there was no better method of bone-grafting than to transplant part of the patient’s own skeleton to the affected part of the body. The problem was to find a way to perform these operations quickly enough. lf he could make a machine that would cut through human bone as fast and easily as those zinc saw teeth had slid through the turnips, the trick would be done. Finally Doctor Albee devised a little steel saw, an inch and a quarter in diameter, with tiny teeth, and driven at high speed by electricity. This he fitted with depth gages, to determine the depth of the cut. That was the beginning of his wonder- ful new surgical technique. In the fifteen Dr. Fred Houdlett Al- bee, repairer of human bones. He has restored hundreds of cripples. years that followed, Dr. Albee perfected his device and taught its uses to thousands of surgeons. As a result Dr. Albee is one of the busiest men in the world. In addition to his medical school work, he personally operates on hundreds of cases each year. In his spare time he is president of a bank, editor of a magazine, consulting sur- geon to three railroad compan- ies and twenty hospitals, and chairman of the New Jersey Rehabilitation Commission. Besides, he goes abroad each year to deliver lectures in European universities. The Sleep Doctor EING tired, even in a good cause, is no legitimate reason for pride; fatigue may be as reprehensible as drunkenness and as dangerous as asphyxiation! That, in effect, was one of the startling conclusions presented recently before the National Academy of Sciences by Dr. H. M. Johnson, psychologist of the Mellon Institute of Industrial Research of the University of Pittsburgh. Dr. Johnson is probably this country’s leading authority on sleep. He has di- rected a painstaking investigation in- volving the observation of some ninety different people, ranging in age from six- teen days to sixty-three years. He found there is no essential difference in the effects produced on the human body by the poisoning resulting from fatigue, from intoxication, and from as- phyxiation. A small amount of alcohol, a little fatigue, and a slight decrease in the supply of oxygen act as stimulants; large quantities of liquor, great fatigue, and a considerable oxygen decrease are mental and moral depressants. One question asked by thousands, ““How much sleep do I need?” he con- fesses himself unable to answer. That, says Dr. Johnson, is a matter which each individual must settle for himself. Dr. Johnson declares that he him- self can get along with but six and a half hours. Born on a Missouri farm -. forty-four years ago, ; ™ 7 _ hisfirst job was with m Vers Loe ae © % é a railroad construc- tion gang in the swamps of south- west Arkansas. Dr. H. M. Johnson, leading authority on sleep, says “Fatigue is just like intoxication.”’ Elinor 4 Later he was edu- cated at Missouri Valley College, Johns Hopkins Uni- versity, and the Smith, teen-year-old endurance flyer. “I sing as I fly.’’ by engineering University of Chicago. He did research work for the General Electric Company in Cleveland, and during the war was q captain in the Sanitary Corps. For foy years he has been director of the invest}. gation of sleep at Mellon Institute, A Girl Ace at 17 SEVEN TEEN-year-old girl aviator thrilled the world the other day when she remained in the air thirteen hours, sixteen minutes and forty-five seconds. She was Miss Elinor Smith, a recent high school graduate of Free. port, N. Y. Her plucky per. formance broke the world’s solo endurance record for women at the time, but soon afterward she lost the cham. pionship to Miss Evelyn Trout, of Los Angeles, Calif., who flew for seventeen hours, five minutes and _ thirty-seven seconds. Undaunted, Miss Smith, at this writing, was planning to try again. Completing her endurance flight, Miss Smith made a perfect night landing at 3:33 a.m. at Mitchel Field, Long Island, where she had taken off in her Bluebird biplane at 2:17 the previous afternoon. To eager questioners she said that she had “‘sung all the popular jazz songs she could think of’’ to keep her mind off the cold during her long, frigid flight. Young as she is, Miss Smith has 425 hours of fiying to her credit. She took up flying when she was fourteen, but had to wait two years before she could get a private license. Last summer she reached an altitude - of 11,663 feet. A Fridtjof Nansen, dean few months ago the of explorers. He’s go- Department of Com- merce ordered her not to fly for fifteen days because she had flown under the four East River bridges— a feat never before attempted by 4 woman. When not flying or tinkering with her plane, Miss Smith devotes her time to horseback riding and music. She plays the piano and a banjo. seven- ing to the Pole this timein Graf Zeppelin. The Dean of Explorers LTHOUGH almost sixty-eight—an age at which most men wish to enjoy retirement and comfort—Fridtjof Nansen, (Continued on page 136) m eV ha ba no ele

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RIL, 1999 >. Camp. S wheat eering, _Tesearch ~ompany ar Wasa For four > investi. tute, it 17 ~year-old illed the when she thirteen ites and She was a recent of Free. icky per. > world’s cord for but soon he cham- t, of Les seventeen rty-seven th, at this in. ght, Miss nding at g Island, Bluebird fternoon. that she songs she mind of id flight. ansen, dean 3. He’s go- | Pole this f Zeppelin. e she had oridges— dd by @ with her time to he plays ‘ers ight—an wish to -Fridtjof page 135) Apri. 1929 By v ROBERT E. MARTIN RESS a button and turn on the sun. It’s that easy. Anyone can have a private sun hitched by a few feet of lamp cord to the near- est convenience outlet. “Health lamps” now are being offered in many varieties. All have one aim—to supply artificially the healthful rays of sunshine. But the individual who is not getting enough natural sunlight, and who seeks a lamp that will supply it, may well be bewildered at the number and variety offered him. Which is the best? Are they really good, after all? These are questions being asked in every section of the country today. It isn’t necessary to point to rickets—a favorite example of the dire effects of darkness—to emphasize the beneficial bodily effect of sunshine and the danger of its lack. According to many authorities a person habitually exposed to sunlight 's best fitted to meet extremes of heat and cold. Certain types of tuberculosis are treated by sunshine, natural and arti- ficial. The “‘ductless glands” of the body, whose secretions are important in shaping our emotions, are now believed to be affected by the sun—which may account for the cheering psychological effect of a bright sunny day. We constantly are finding new curative powers in the rays generated by the sun. But our present-day civilization keeps many of us out of the sun for most of every day. As a result sunlight lamps have been developed. Good lamps and bad ones have been devised. Some have no more medical value than an ordinary electric light bulb; others produce rays Treating a patient in London Light Clinic with a health lamp sim- ilar to that used for King George of England during his illness. SWITCHING Valuable Facts About How to Choose and Use the New Health Lamps POrULAR SCIENCE MONTHLY ON the Lyjng on the bed in his own home, this child enjoys an electrical sun bath in the health- giving rays of the newest type of carbon sun lamp, approximating those of the sun. Out of this need for an artificial sun, two princi- pal types of lamps have come. One of these is known as the “mercury vapor” lamp. Its peculiar greenish Jight, familiar in the studio of any commercial photog- rapher, is a relatively “cold” light. The other type, the “‘carbon arc,” produces its rays from a pair of white-hot carbons, across which plays an electric are. It is intensely hot. The choice lies between these two. To understand the difference we must first examine the properties of sunlight. Sunshine looks white—but it isn't. Actually it is a blend of all the colors of the rainbow. You can see these colors when sunlight is split up, as by passing it through a glass prism, to form the rain- bowlike color band, violet at one end and red at the other, technically known as the “spectrum”. But sunlight also has in it rays of light invisible to the humaneye. One band of these rays, found just out- side the red end of the spectrum, is called “‘infra- red” rays. These are the heating rays of the sun. Another group of invisible rays lies outside the oppo- site, or violet, end of the spectrum and is termed “ultra-violet”. These are the skin-tanning rays. Mercury vapor lamps, inclosed in quartz tubes, are effective in the pro- duction of active ultra- violet rays. To be sure, most “‘health lamps” pro- duce, or claim to produce, a large amount of these rays. But the mercury vapor lamps, sometimes known as “ultra-violet lamps,” have a concentra- Goggles are worn to protect the eyes. tion of energy from the ultra-violet part of the spectrum, making it possible for an individual to obtain in a short time the benfiecial results of ultra-violet light arti- ficially. But caution is necessary. Ex- posure foolishly prolonged will result in severe burns. HE “carbon arc” lamp is of entirely different type. Unlike the mercury vapor lamp, it endeavors to approximate all of the rays of natural sunshine. The United States Bureau of Standards re- cently described it as the nearest approach to natural sunshine. It contains ultra- violet rays in therapeutic quantities, the infra-red rays from the other end of the spectrum, and rays from in between. Lamps of either of these types, re- liably made, may be useful for health treatment. So far the mercury vapor lamp has found perhaps its widest use in hospitals. The carbon arc has been sold widely for household use. With either type, tinted goggles are worn during a sun bath. Before buying a lamp, in any event, it is well to consult a physician as to the exact needs of the individual patient. Recent improvements and mechanical refinements have resulted in lamps pe- culiarly suited to use in the home. One of these, for instance, has an automatic shut-off mechanism, operated by a time clock, that makes it possible to use the lamp without fear of over-exposure. In the de- velopment of carbons for the are type of lamps, outstanding improvements have been made, exemplified in a recently- introduced “electric sun.” Behind it lies the romantic story of a young man witha leaning toward photography and an in- satiable curiosity. Looking for a lamp with suitable light for night picture-taking, Roy Mott, a young research engineer of Cleveland, O., tried hollowing (Continued on page 139)

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| Am | earning to POPULAR SCIENCE MONTHLY ARAL I looked down at the ground. We were banking, turning. My stomach was shrinking, Everything was blurred. Jordanoff’s voice boomed through the speaking tube. Be a i lyer In the Air at Last!—More of the Stirring Adventures of a Greenhorn Who Is Breaking into Aviation MECHANIC in greasy brown overalls jerked the propeller of the blue biplane. The motor snorted, barked, roared. A blast of br vn dust swept back. In .4e forward cockpit sat a begoggled instructor. In.the after cockpit sat a pale, begoggled young man. The plane taxied away. A man stand- ing near me laughed and said, “His first lesson,’ and two other men laughed. I couldn’t even smile, Before long, I, too, would be sitting in an after cockpit. But first I wanted to take things in; get the feel of the place. A little nervous? Maybe. Mostly bewildered. Everything was so strange. It was my first visit to Curtiss Field, N. Y., since passing the physical examina- tion of which I told last month. The air By LARRY BRENT hummed with the exhaust of unmuffled motors. Planes were everywhere, planes of many kinds, gliding down out of the sky, circling above the field, taxiing over the uneven ground, lying still at the edges of the field or in the rows of great han- gars that flanked it. I sat on a low board fence to watch—and get my bearings. A man of about my age in flying clothes sat down near me and fixed his attention on the sky. Presently he turned and looked at me. “Student?” he asked. “On my way to sign up,”’ I answered. “Ever flown?” “No.” I hated to admit being so green, but he seemed friendly. His name was Gula Owens, although he went by the nicknames of “‘ Bubber” and “Bud.”’ His home was Miami, Florida. He was a student, having saved enough for his course by selling bonds. “Who are you having for an instrue- tor?” he wanted to know. “Can I pick my own?” “Sure! Did you see that tall bird with the black mustache and the aerial camera who breezed by a minute ago? That's Bill Winston—the man who taught Lind- bergh. He’s flown over 6,000 hours.” “T’ll take him,” I said promptly. “You can’t. Bill isn’t doing regular instruction any more. He’s the field man- ager now—boss of the works. Il Lieutenant Phillips until I soloed. He's an Army flyer, one of the best. Since he left I've had Randy Enslow. He used to be Lindbergh’s sidekick, barnstorming, before Slim went into the air mail. Get on Enslow’s list. You'll like him fine. He rea eee 4S =o i as eee 2

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RIL, 1999 vn at the Ve were ning. My shrinking, ng was ordanoff’s i through ig tube. er for his instruc- rd with camera That’s it Lind- rs.” |. He's ince he used to orming, Get on ie. He Apnit, 1929 rawhide and that’s what you want. instructor has a different method, dee ’re all topnotchers. Better money e : pol jn instructing than any other ‘ ing. bind oft ork, too,” I ventured. _ “My eye!” snorted Owens. ““W ould ou feel easy, sitting in that front cockpit, ‘ith your hands and feet off the controls some dub behind you doing every- - 9 inside out and backwards? I'd rath- er fly night mail over the Ozarks! How’d ‘ou feel if your student suddenly got poe and froze onto the controls? What would you do?” [couldn’t answer. Owens went on: “{70U’D grab the Pyrene can and reach back and sock him on the head yithit! Then you'd grab the controls and et her out of whatever it was she was in.”’ “Do students often freeze onto the controls?” ; “Hardly ever.” I asked Owens who some of the in- structors were. “There's Jordanoff. He flew in the Balkan War and was a German ace in the Big War. He’s flown since he was fifteen. Before that he built gliders and made parachute jumps off housetops with um- brellas. There's Johnny Wagner, a bird of about our age. Another is Bill Purcell. He used to be chief chemist for the Cur- tiss motor factory and perfected two metals now used in planes. “Then there’s Coth, who was a Royal Flying Corps ace. Coth soloed in one lesson of fifteen minutes! That’s the way they rawhided ’em in the war. You took Photographs of the author by D. Warren Boyer Jordanoff showed me how to work the ailer- ons. “‘When you push your sticktothe right,”’ he explained, “the . ailerons on the right wing go up, those on the left wing go down, banking your ship.” Then he explained the rudder and elevators. You steer with your feet; the pedals turn the rudder. Your stick moves the elevators. This broken-away view shows how the mech- * anista is controlled. © POPULAR SCIENCE MONTHLY one lesson with an in- structor, then went up solo. It was like being kicked off the dock into deep water. Sink or swim.” ; A mechanic walked over and said to Owens, “‘She’s ready, Bubber.” Owens stood up and said casually, “See you later.”” He went to one of the blue training planes and climbed into the after cockpit. He taxied it to the end of the field and turned it into the wind. I saw the sunlight on the slowly revolving blades flash and scatter. The plane came down the field. The wheels lifted from the ground. It began to climb. The wheels were still spinning when it roared over my head. I asked myself if I would ever be able to fly a plane with such skill and confi- dence. I decided to end the suspense. In the lee of a large hangar was a small white building, the office of Charles—*‘ Chic” —Ga- ver, schoo] manager. Chic Gaver was alone. I gave him the letter I had received the previous evening from the Department of Commerce doctor who had examined me, certifying that I was physically fit to fly. And I gave him a cashier’s check for $600, which represented most of the savings of three years of hard work on a newspaper. He was pleasant but very casual and businesslike. He pulled out a long orange card and began asking questions. Full name? ‘Lawrence Arthur Brent.” Age? “Twenty-two.”’ Education? “‘ High school.’’ Occupation? “Newspaper re- porter. But,” I added firmly, “Tm through with that. I ex- pect to become a flyer—and stay one. I hear there’s a big demand for experienced flyers.” Gaver smiled. “‘How are you going to get your experience— your first fifty hours?” “T understand,” I answered, We were up 800 feet, sailing along beautifully, when Jordanoff raised his hands—the signal for me to take the controls. My right hand was on the stick, my feet on the pedals. I was flying the ship! “that you give students jobs and let them work for flying time.” “Not any more,” said Gaver. “It didn’t work out. Our first rule is safety. We won’t have men working on our planes if we can’t fire ’em for making mistakes. Now we hire only good licensed mechan- ics. If they want to spend their wages for flying time, that’s up to them.” ASKED Gaver how long it should take me to finish my twenty-five-hour course, including ground school. “From six to eight weeks, depending on the weather. The school is open all win- ter. Have you decided on your in- structor?” “Randy Enslow,” I said. “Try to fly every day. You can forget - what flying you’ ve learned in one lesson if you skip many days. Every afternoon there’s a lecture—sixth hangar down. In- structors, other pilots, and aeronautical engineers cover flying from every angle. Lectures are free. Don’t miss them. If you have a pencil and paper, take down some notes. They’re im- portant.” I had a pencil and notebook. He began. “The first point to bear in mind in flying is speed. Speed means safe- ty in flying. Without speed, an airplane will fall like any other heavy object. It stays up be- cause it moves fast. ““Most students have a tendency to over-con- trol. That is, they grasp the stick instead of hold- ing it lightly. “Always coédrdinate your hand and foot mus- cles. Never move your stick without moving your rudder.

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Pushing the stick forward moves the elevator down, making tail go up and nose go down. “Don’t fly mechanically. Understand the why for everything. If your instructor does something or asks you to do some- thing that you don’t understand, ask why. In time, you'll fly by feel. ** Always ride your ship through. That is, be a part of it. “ ALWAYS fly] relative to some fixed object—the horizon. Any ques- tions?” “How about flying clothes?” “You can buy everything you need in the stores on the field. For winter flying you'll need warm gloves, a warm flying . suit, and fleece-lined boots. Helmet and goggles are six dollars each. You can pay from sixty dollars to two hundred and seventy-five dollars for a suit. A fine leather suit with blanket lining is the most expensive. A fleece- lined canvas suit costs you sixty dollars.” “What is the hard- est thing to learn in flying?” “Landing. Taking off is difficult at first. Air work is compara- tively easy. Landing is hardest because it calls for a brand-new use of your judgment of speed and distance. In driving a car you deal with one speed and one distance. In landing a plane, you deal with two speeds and two distances.”’ He filled out a small white card and gave it to me. The next hour I spent strolling around.the flying field, watching the planes and talking with a number of students. Then I got my flying clothes and walked down to the little green sentry box which served Bill Bates, the contact man, for an office. I gave him the white card. It was a flight report card and it revealed what a raw beginner I was: ME IN AIR, HOURS—0. LANDINGS—0. AIR WORK—NONE. Bill Bates said: ‘Enslow is sick today, Mr. Brent. If you're anxious to get started, perhaps some other instructor will take you. I'll ask Lieuten- ant Jordanoff.” He called to a dark-faced handsome young man in brown leather flying suit with fur col- lar and helmet. His goggles POPULAR SCIENCE MONTHLY were on the forehead of the helmet. Jordanoff came over. He was not smil- ing. Wise brown eyes took me in. Bates introduced us. We shook hands. Bates said: “Brent is one of Enslow’s students. Enslow won't be out today. Brent is anxious to get going. Will you take him?” Said Jordanoff to me: “How many lessons have you had?” **None.” Moving his arms, Jordanoff illustrated to me the secrets of banking. ‘‘Remem- ber,”’ he said, “‘if you turn the rudder with- out moving the stick to bank the ship, it will slip.’’ Left: right bank; stick to right. “Never been up?” > “No, sir.’ “T will be delighted to take you,” said Jordanoff. He smiled and bowed. Assen Jordanoff is one of the most polite men I have ever known. ~ We strolled toward one of the blue training planes. My heart began banging I presented my doctor’s certificate and a check for $600 to“Chic’’ Gaver, school manager. He pulled out a card and began asking questions. Pushing the stick to the left tips the plane to the left, as pictured here. when Jordanoff buckled his helmet under his chin, smiled and asked, “ Are you taking up flying for reer ation?” “No, sir; I'm going to be come a commercial pilot.” That seemed to please Jor. danoff. “You look to me,” he said, “as if you should make an ex. cellent pilot.” “Can you tell by a man’s looks?” “Often.” I asked him what it was. He shrugged, smiled again. “Some thing about the eyes, perhaps You have it.” I felt grateful. Swiftly Jor danoff walked me around the plane, pointing out its different | parts. Then, “If you will g¢ "| into the after cockpit, I wil explain.”’ I climbed into the after cockpit. It was the first time I had sat in an airplane cockpit. My first surprise was the dis tance down I went. My chin was jus about level with the cockpit cowling. OMING up from the floor betwee my legs was the control stick, or joy stick. At the top end was a rubber handle like the grip on a bicycle’s handlebar. At my feet were pedals, fairly well over on each side. They reminded me of bicycle pedals. But with them, all resemblanceto being on a bicycle ended. Jordanoff said: ‘‘Take the stick. Ab ways remember to hold it lightly. You will be surprised what a light touch wil make the plane do anything you wish. When you push the stick forward, the nose goe down. When you pull it back, the nose goes up. When you push it to either side, the plane tips in the direction of the push. It is absurdly easy.” He smiled. I tried to smile Well—it sounded easy. **Now for steering,”’ went on the instructor. “You stee with your feet. When you push the right pedal, the ship goes to the right. When you push the left pedal, the ship goes to the left. Again—absurdly easy!” Again he smiled. Again I re frained. Students had told me (Continued on page 145)

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AMES L. SMITH is, in a sense, mayor of one of the busiest and most spec- tacular cities in the world. He is operating manager of the Woolworth Building in New York, the tallest building in the world—a_ skyscraper city within a city. He watches over the welfare of 12,000 and more inhabitants of a perpendicular POPULAR SCIENCE MONTHLY 31 turned into a thick black pall. The _ superintendent’s office was. notified. Two leaps and Jim. Smith was in the building’s fastest elevator, swished up at a terrific rate. The fifty-fourth floor (still four stories from the top gallery) was enveloped in choking smoke. Downstairs, four stories be- low the level of the street, the left tips the larger than Emporia, Kan., emergency fire pump was made tured here. on Nev. And he presides ready. A turn of the hand and over a rapid transit system al- 500 gallons a minute could have uckled his most topsy-turvy in that its been spread over the fifty- chin. He swift cars go straight up and eighth story of the building at a “Are you down, a mart with 25,000 tran- head pressure of 820 feet. All for recre sients a day, police and fire de- hands were at their posts. rtments, a hospital, a bank, By this time a crowd of 30,000 ing to be § great power plants, restaurants, or more persons were gazing up pilot.” a swimming pool, a college, a at the fire, which actually did please Jor magnificent cathedral whose exist but only within the safe fine-wrought spires reach out confines of a small stove used by ,” he said ‘nto the very heavens. roofers. These rogues, seeing iake an ey. Jim Smith is young, but the the beginning of excitement as waters of his experience run the bootblack ran across the y @ man’s deep. His mother’s father di- street and attracted attention, rected the operation of buildings threw half a dozen staves of a many years ago, and every one tar barrel on their fire to give the it was. He around Wall Street knows his mob a real thrill. in. “Some father, Bernard Smith, for more 8, perhaps than half a century manager of HE giant pump, ever ready the structure that houses the for action, did not have to be wiftly Jor. New York Stock Exchange. used. It could easily .have ex- round the “Ever since I played with tinguished any fire in the build- ts different blocks I knew that some day I ing in short order. ou will get would operate a great building,” So it happens that Smith is pit, I will he told me. ‘“‘When I was still waiting for the big emer- graduated from Manhattan Col- gency; which, if possible, he will rit. Tt was lege about fifteen years ago I avert. But no one has ever n airplane knew just what I wanted to do. An up-and-down city of 12,000 inhabitants—the Woolworth Tower jumped from the Woolworth is the dis. The fever runs in the Smith as seen through the arch of New York’s Municipal Building. Building. Bandits have never 1 was jut® family. I have a little daughter, yet attacked the fortresslike wling. she’s seven, and when she grows e vaults of the Irving Safe De- up I hope there'll be women posit Company which it houses. r between building managers. I want her UL a} A} L A} Oh No elevator has ever fallen. No ick, or joyf to have a crack at this game.” riot has ever taken place. And oer handle if it’s humanly possible, there llebar. At BVIOUSLY, Jim Smith’s won't be any slip that might ll over on job looks good to him. No “tie up the works.” of bicycle wonder, then, that his compli- Most of the works are in the ablanceto§ cation of duties hardly feazes S C ra e 7, basement. There is the ma- him. He takes ceaseless activity chinery for heating, lighting, and ome AL§® asso much routine. He does his ; ventilating this up-and-down tly. Yor— job deliberately, because he 2 Tr city. From there its traffic is ouch wil wants to be pir and collected, B y PETER VISCHER regulated, its streets cleaned, and anything§ if ever emergency arises. policed. push the There’s no telling what will happen in Once it looked as though the crisis had Taking one of the bronzed elevators I 10se gos the Woolworth Building on any day. come. A grimy bootblack in City Hall rode with Mr. Smith down into the base- ll it back, § The tower of Woolworth rises majestic- Park squinted upatthe Woolworth Tower, meat. The walls and floors are tiled and Vhen you ally 792 feet and an inch into the air, and frowned, and tumbled ex- the ceiling is enameled. Busi- the plane fits sixty floors swarm with people. citedly across the street nesslike young men moved to and n of the “In a building as large as this one we shouting, “Fire!” Thou- fro, and only the fact that they easy.” have to be especially careful about sands of persons gathered, are in overalls suggests that this to smile § things,” he said, modestly, “because stopped, and craned their is not a traditional place for white y. even the slightest of slips might tie up the necks. High above the collars. > wenton§ works.” street, smoke seemed to be “These men are en- ‘ou steet And because Smith has been so care- curling from the windows. gine-room workers,” Mr. you push f ful, there hasn’t been a real emergency in . At first a wisp, it quickly Smith explained. “‘Over ip goestof the Woolworth Building since that thrill- there is the power plant. push the} ing night of April 24, 1913, when Presi- You know we manufac- es to thef dent Wilson pressed a tiny button in the ‘piiasaniilh tibiae, ture our own light and easy!” White House and 80,000 brilliant lights; town’’—James L. power. We like to be gain Ire § dedicated the masterpiece of Cass Gilbert Smith, operating independent. | told mef and brought to fulfillment the dream of psa ng feb ?_ “Our power plant con- 145) Frank W. Woolworth, exalter of nickels 2h is as complicated sists of four engines and and dimes. as running a city. (Continued on page 140)

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he Biggest Kngineering Joh Hoover Ever ‘Tackled 4} ERBERT HOOVER’S §ssup- porters, during the late caloric campaign, called him the sec- ond engineer who had ever stood for the office of Presi- dent; the first being George Washington. In this, they merely made a flourish of politics. Washington, so far as I can find, never gave himself that title. He had practiced in his youth some land survey- ing, the most’ primitive branch of the craft; but he was primarily a POPULAR SCIENCE MONTHLY By WILL IRWIN before it became an issue of international politics, was only a great job in human engineering. All the subsequent work of his ever-widening career—the American Food Administration, the European Re- lief Administration, the Russian Relief, the creation of a Commerce Department that functioned—has about it the same touch. Only, it has also the human touch. The combination of these qualities is the reason why we are inaugurating Herbert “a Aan, 1929, Fi } wholly within the United States and pa as a volunteer into what he called “su big game.” That did not mean politim: necessarily or even probably; just some chance to carry into wider fields tha engineering method which had become gy instinct. . It was a wonderful apprenticeship however; working as though designed { mold the unique world figure that he has become. Of its central facts, the pul knows little. After three yeam farmer, a dealer in lands, and a of inspection and managem soldier. Gigantic figure of a practical man though he was, ~ he did not show in his public administration the engineer’s mind. If he had, he would have stood a century in advance of his times. The day of the engi- neer was yet to dawn. Hoover, on the contrary, is fundamentally an _ engineer; from his survey of Pyramid Peak, California, during the summer after his junior year in college, to his last item of exec- utive work in the Department of Commerce, he brought to all tasks the engineer’s atti- tude—the realistic mind, the moral obligation of approach- ing truth from a basis of facts, the passion for harmonious co- ordination of parts. In his time, he saw engineer- ing greatly extend its scope and usefulness. When he began, it dealt with single jobs like sink- ing a shaft or setting up a plant. When, in 1914, he sev- ered his formal connection with the craft, it was taking supervision not only of gigantic industrial enterprises as a whole, but even of industries as a whole. On the basis of known facts and the laws of science, it S HERBERT HOOVER assumes stupendous task as President of the | United States, everyoneis wondering: | What will he do? What problems | will he be called upon to meet? Will he write his name large in history? Here is fact on which to base answer—a keen, searching analysis of our | new President by a famous author who has_ | known him intimately from youth. Thirty- | four years ago Will Irwin, a freshman in Leland Stanford, Jr., University in Cali- fornia, chose as his hero a leader of the senior class who was destined to rise to the greatest office in the land. From the close friendship which began in those college days Mr. Irwin has gathered a deep understanding of the engineer who captured wealth from the jungles, turned disorder into smooth-running machinery, and organized vast enterprises of industry and human welfare. What Will Irwin tells us here is of special importance because it points out clearly a thing that has been all but lost in the thousands of words written elsewhere—that the great problems now confronting our nation and its new President are those de- manding engineering training and ability for their solution.—The Editor. his | your in our own Far West, Australia. || sent to California for a young man to introduce Ameri gold mining methods, consid ered the best in the word Hoover got the job. And he” | found, before he finished '| Australia and passed on China, a striking opportunity for a young man. In most dé partments of mining and if most heavy branches of neering, the United States the world. I am not indulging sinful national conceit, I , when I say this. It was just the fruit of our experience in breaks ing, during two generations, @ wild continent of unruly rivers, intraversible deserts, and im passable mountains. Further, very few American engineers had ventured abroad. Hoover seized the opportunity. All his work, in the years up to 1914, had the same general cast, With American assistants and American machinery, he was introducing our methods into the untamed regions of foreign lands. 7 ND here is another super | lative about Hoover. No |} American before or since ever was eliminating wastes and multiplying collective effort. Hoover kept abreast of the times; his career is typical. He began in 1896 by reporting on mines and superintending their development. By 1914, he was mak- ing great low-grade mining properties pay dividends by the process of coérdinating their complex parts. When, on a day’s notice, he began his public career by tak- ing charge of the Commission for Relief in Belgium, he broke perforce all connection with business, and seemed to be breaking with his past. He was not, really; those nineteen years of professional practice were father to his public work in the sub- sequent fifteen years. The Commission for Relief in Belgium, Hoover President of the United States. He had, during those nineteen years, a long, hard, and interesting apprentice- ship. Here again lies a fundamental differ- ence: between Hoover and any other man whom we have ever elevated to the Presi- dency. All others, during their early careers, had taken part in public life or Government service; most of them had long been pointing toward the White House. But if you had suggested to Hoover, before 1914, that he would some day become President, he would have laughed. At most he held only a vague hope that in his middle age, when he had made his pile, he might pull himself operated a single private busi- ness on so wide a geographi scale. He worked personally on every § continent except South America; and — even there he was at times absentee man- ager, or expert adviser, for properties in ~ Peru and Brazil. Nominally, he was 4 mining engineer. But any mining man knows that when you open a new prop erty in wild country, you must almost run the gamut of the craft. His early Aus tralian job, for example, involved the erection of shaft houses and reduction works—construction engineering, me — chanical engineering, chemical engineert- ing. A brief service with the Chinese government as expert geologist; then, after the Boxer (Continued on page 161)

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POPULAR SCIENCE MONTHLY a | - Drawn espetially for Poputar Science MontHLY by B. J. Rosenmeyer HERBERT HOOVER, THE NATION’S ENGINEER A remarkable study of our new President at his desk. The first scientist to become the nation’s chief executive, he assumes his task Pa ji Me ' at a time when thé Government is more concerned with problems of engineering science than ever before in its history. OF. 3

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ROM coast to coast Ameri- cans are trying a hz.ad at the thrilling sport of motorless flying. Here are views of the first official glider contest held by the California Gliderr Association on the sand dunes near San Fran- cisco. At the right a ground crew is catapulting one of the machines into the air by means of a tow- rope. Vance Breese, noted Pacific Coast pilot, is handling the craft. eee ene a RET nn Fun? Ask Charlies Furgeson, president of the California Gliders Association. Here he is at the controls, ready for a glide. Launching a 500-Ton Gate ESEMBLING a giant scow, this 500-ton steel gate was launched with a mighty splash recently at Brooklyn, N. Y. It is to be the portal of a new dry dock for ocean liners in the Erie Basin of New York Harbor. This dock, 715 feet long and 113 feet wide at the top, will accommodate larger vessels than any similar structure near New York. The gate is to be lowered and raised by water ballast tanks. POPULAR SCIENCE MONTHLY U. S. Gliders 3 Match Skill | 28sec remained in the air several minutes. The glider, of the German training type intro- duced to America last year, was pulled Camera Stories of | ie sista nse wets arene a Unusual Events ing advantage of upwatd air currents, Another Speedy Challenger ERE is the latest speed creation of Major Mal- colm Campbell, famous British driver who — broke the world’s record at Daytona Beach, Fia., — last year, only to be surpassed soon afterward by Ray Keech, the American. Like Maj. H. O. D. Segrave, whose new car is pictured on the opposite page, Campbell expects to capture world speed honors for England this year. His new streamlined car, with a nose shaped like an airship’s, is driven by the same engine which sent him at a speed of 206.9 miles an hour along the Florida beach-track. The spectacular launching of the great dry dock gate. The million pounds of steel strikes the water, churning the waves into seething foam.

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Apamt, 1929 POPULAR SCIENCE MONTHLY 35 APRIL, 1999 |Challenging U. 5S. Speed Records Major Segrave’s racing monster Golden Arrow shaped like a giant fish with long, streamlined tail. With it he hopes to reach the amazing speed of 240 miles an hour at Daytona Beach, Fla. America’s speed supremacy on land and water js being challenged this spring by the famous British racer, Maj. H. O. D. Segrave. He recently brought to America a new speed car, the Golden Arrow, and a powerful hydroplane, the Miss England. Above: Major Segrave (right) and the giant engine in his water croft, with which he expects to beat the record of te 92.8 miles an hour set by Gar Wood Jast year. Po At the right, Major Segrave (wearing derby) is seen superintending me- chanics tuning up: the great 900- horsepower engine of his new racer. ng a safe He is convinced that it will smash the pictured world record of 207.6 miles an hour, tions, he The car cost close to $100,000, es. The pe intro- When he's not racing, Major Segrave tinkers with a s pulled model railway for recreation. At the right he shows ope, and part of the elaborate four-track system which he has | in tak- been building for fourteen years. It has bridges, -urrents, tunnels, and automatic electric control devices. ~*~ ee Rilid Wa ewe, - Robot’s Eye Controls Traffic; Train Obeys Its Master’s Voice Dr. Phillips Thomas (right), Westinghouse engineer, demonstrates «his new “electric eye” which, buried in the pavement, flashes red traffic signal when car approaches main road from side street. 4 Y as yer Major Mal- — iriver who | each,. Fla., © erward by H. O. D. 1e opposite orld speed treamlined , is driven a speed of ach-track, ‘y This amazing robot traffic cop responds to the shadow of a car passing over it. It was invented to avoid present de- lays in main wate” ale’ \ - eS ee wind W. H. Jones, of the General Electric Company, with toy electric train which obeys its master’s voice over telephone. When he says “Stop!” or “Goi” it responds instantly.

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36 POPULAR SCIENCE MONTHLY APRIL, 1999 Snapshots of Unusual People Weather forecasting is just part of the day’s Dr. George D. Marshall, of Kokomo, Ind, work for Raymond L. Ditmars, curator of once a blacksmith, uses his mechanical skij mammals and reptiles in the New York Zoo. to make his own orthopedic appliances jp cure needy crippled children free of charg, + ere” Sixty-five years old, but as enthusiastic as any young airman, is J. L. Gray, pilot of Dallas, Tex. ta! G The world’s only masters of buhl craft— the art of inlaying carved metal on tortoise shell—work in a shop near Paddington, Eng. oe x Seth Bert Gracier, a San Francisco chemist, claims to have discovered a way to harden gold, silver, and copper with an alloy of alu- minum. Gracier is seen taking a piece of the new alloy from a crucible in his laboratory. Jules L. Buck, Camden,-N. J., big game hunter who traps wild animals for zoos, is teaching tricks to a young gorilla cap- tured on his latest expedition to Africa. Executive of a New York firm making his new electric steam heater for trains, W. E, Hudson keeps his job as railway conductor.

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ee ER edo we r (PZ me, = 4 a. 2 meee German architects transformed this old water tower in Berlin to house 100 flat- dwellers in a home of rare and charming de- sign. Here the folk may literally “round out’ their lives amidst a setting of real beauty. This tower, which one might take for a quaint lighthouse or a new-style garage, is actually a monument to learning, for it was built to test, in every way science can devise, the relativity theories of Dr. Albert Einstein, which have upset many of the beliefs long held by physicists. In the observatory atop the tower, located in Potsdam, Germany, are wonderful instru- ments that put to proof the Einstein laws of light, time, and space, as applied to problems of interstellar distances, which have revised the mechanics of Sir Isaac Newton’s gravitational calculations by using the idea of four-dimensional space. , < — ° — POPULAR SCIENCE MONTHLY Designed to catch the eye, this new film palace in Berlin is brightly illumined by horizontal bars of light that enhance its severely artistic facade.

Beauty in the workaday world is echieved by the classic architectural that make this tall, steepled structure in Bre- men, Germany, look like almost but what it is—the elevator of a mill,

FA a g < £ ig 4 : : EB e ~~ Editors and writers of the Anzeiger can ° study the stars in the planetarium atop that newspaper’s new home in Hanover, Germany. Every device of modern jour- nalism was built into this unique plant. } Like a mammoth pipe organ towering | toward the sky in daring originality of design, this stately church of truly dig- nified beauty is a memorial in Copen- hagen, Denmark, to N. F. S. Grundtvig, a preacher who died fifty-six years ago while trying to reform religious views.

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The world’s largest steam locomotive. it hauls trains over mountains on the Northern Pacific. the comparative size of the man standing just ahead of the cab, Latest Engine Uses Every Hour Enough Coal to Heat Two Houses All Winter TWENTY-TWO-WHEELED juggernaut of the rails, the larg- est steam locomotive in the world, recently was delivered to the Northern Pacific Railroad. Shown above, it is the most powerful Mallet- type train-puller ever built. It weighs 1,100,000 pounds and, with its tender, is 125 feet long. In an hour it burns twenty tons of coal, enough to keep two average houses warm all winter. It will haul a double freight train two miles long ona level, but is being used to replace “double- headers” on mountain grades between Glendive, Mont., and Mandan, N. D. Its comple- tion is a fitting climax to a century of amazing progress in engine designing. America’s railroading had its beginning when Col. John Stevens’ cogwheel-driven “iron horse” pulled six persons around a circular track on his Hoboken, N. J., estate at the then terrifying speed of twelve miles an hour, one day in 1825. POPULAR SCIENCE MONTHLY Strong as 6,000 horses, Note Right: A close-up of Amer- ica’s first locomotive, built by John Stevens at Castle Point, Hoboken, N. J., where, in 1825, it carried six persons at the “‘terrifying”’ speed of twelve miles an hour on a circular track. It was driven by a cog geared to a track between the rails. ad girtonnes tr / “ee \ Here's a replica of the Best Friend, one of the first American-built locomotives. In 1830, it made thirteen miles an hour in runs on the South Carolina Railway. It was wrecked when its boiler blew up after seven months’ service on the railroad. Electricity from its own power plant propels this 400- horsepower gas-electric loco- motive. It is a new develop- ment for short hauls, elimi- nating expense and the peril of a third rail, and has been put in operation on some American railroads to trans- port passengers and baggage. APRIL, 1999 People laughed at it, yet, five - years later, a boat tied up at =~ Charleston and delivered 3 : bulky package to the South Carolina Canal and Railway Company. It was the Bes Friend, one of the first Ameri- can-built locomotives put in operation on a railroad in the United States. In November, 1830, it was chugging over the rails at thirteen miles an hour, Seven months later, a fireman tied down its safety valve and the boiler exploded, wrecking the engine. But steam rail roading had arrived for good! As early as 1901, a train covered the five miles between Fleming and Jacksonville, Fla., in two and a half minutes—12 miles an hour! That short distance record still stands. By 1902, there was a ia twenty-hour train schedule between New York and Chicago and, shortly there after, a special train covered the distance between Los Angeles, Calif., and Chicag? in less than forty-five hours. Innovations in locomotives appeared. “Electrics” replaced the steam engines on some runs. Now gas-electric locomotives promise new economies on short and light hauls. They generate their own electric power as they go, avoiding the expense and danger of a third rail. One of the latest types is shown in the lower left- hand corner of this page. TTT SS

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\PRIL, 1999 it, yet, five tied up at elivered a the South d Railway 3 the Bes irst Ameri- yes put in road in the November, ng over the es an hour, rtly there he distance ad Chicage appeared. engines on ocomotives + and light wn electric he expense Ine of the lower left- POPULAR SCIENCE MONTHLY April, 1929 round the Pole in | | / RADIO AND DEPTHOMETER / EQUIPMENT FOR COMMUNICATION 1} OBSERVATIONS AND SOUNDINGS; OF TYPE |, ROOM S——7 MAIN USED IN U.S; NAVY FOR s , Za NS GEO V () ale WORK Th=- —_Z oo rude r 47 WINCH B A sf = a wii ox" — ————— ery CONSTRUCTION a i 8 - a ok le al ; LAVESTIBULE OF INSULATED [/SKID SKYLIGHT =f ——. aia 6) QA HULL /OVER LIVING me ~ J AS’ ) QUARTERS —a : WA LS RNWING we 1} Z FAAOLE FOR. - EA 7 GEOGRAPHI of | SH #work Z Yip vA Ay CREWS QUARTERS / J OFFICER'S AND ENGINEERS 7 CABINS QPOCTOR'S AND COOKS QUARTERS A i eA CAPTAIN'S CABIN U0 : D COMPANIONWAY ~- OTO DECK HOUSE al s MAINCcRBIN x Pad SV ee om _AND GALLEY QUARTERS FOR ESKIMOS SIGNAL FLAGS, FLARES, A ROCKETS Bains ees semper RUDDER AND PRO- 4 PELLER, WHICH CAN Y PROPELLER BE UNSHIPPED INA ivy FEW MINUTES WORKROOM RUDDER AND PRO- | PELLER HOISTED / INTO HULLWHEN ” SHIP ENTERS ICE FIELD FOR FREEZE-IN The unusual design of the proposed dish-shaped polar ship, and ite equipment for scientific exploration. The sturdy construction of the hull, with insulation for warmth, is shown in circle. WATER LINE BRACING CROSS SECTION OF HULL SHOWING “SAUCER” CONSTRUCTION TO PREVENT CRUSHING BY ICE. TO BE SHEATHED WITH GREE HEART, AN EXTREMELY HA TOUGH WOOD FROM BRITISH HONDURAS ie. Oe 39 a Saucer! Ice-locked, the ship will send out exploring planes and dog teams. Above: > Capt. Bartlett with model hull of his craft. IRCLING the North Pole in a 125-foot saucer is the re- cent amazing proposal of Capt. Robert A. Bartlett, Arctic veteran who commanded Peary’s polar ship Roosevelt, and whose own famous schooner, the Morrissey, has plowed repeatedly into the frozen North. He has com- pleted a model of a Diesel-engined ship, only eighteen feet deep amid- ships, designed especially to be frozen in the ice, and a plan of scientific exploration that would send it drifting, with eight men aboard, around the Pole from Alaska to Spitzbergen. For three or four years, Captain Bartlett and his crew would remain fast in the pack ice, while the polar current bore them westward. So shaped that the pressure of the ice will lift rather than crush it, the novel drift-vessel is a dish-sha three-masted schooner. Its hull is sheathed with wood of extraordinary © toughness. Its a. and rudder, used when the Diesel engine is run- ning, are to be hauled into a recess in the hull, to prevent damage to them when the ship is frozen in. Other details are shown in our artist’s drawing.

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et Se 40 POPULAR SCIENCE MONTHLY APamt, 1999 Speeding Ahead with Aviation Reg NE: ic | With ninety-foot wing spread pa Sapa a 3 . ‘ ‘ : and two 625-horsepower mo. net Ss - ; tors, the huge plane is designed to remain aloft twenty hours, Notice the unusually wide body shaped to increase lift, America’s latest air liner—new twerty-passenger cabin monoplane on recent test flight at Newark, N.J. Getting new license plates is one worry of motoriststhatdoesn’t bother the airpldne owner. To obey U. he has to do is to paint new letters and numerals on his machine. Lee Wiley, a Los Angeles flyer, is seen here showing how simple it is, . Constructed like a jeweled watch, this super-sensitive new altimeter registers as little as five feet in the rise or fall of a plane. The large dial is scaled in hundreds of feet, and the small one in thousands: Both dials are illuminated for night flying. Latnching the all-metal, steam-driven dirigible City of Glendale, described recently in Porurar Scizncez Montucy, at Glendale, Calif., for buoyancy tests. Right: Revolutionary airplane motor invented by H. A. Palmer (right) of Boston, said to have no connect- ing rods, cam shaft, or valve springs, and only half usual working parts. Left: A new airplane gasoline gage, said to be the most accurate ever designed, and its inventor, John H. Payne, engineer, Schenectady, N. Y. It measures the gas tank by weight. =— Aebtet £m G2 25 teat ote oe 6A o> ee eo G&G A .& 2 oeeerst «4 eet ee Oe ee Oe tld Oc, OOO ee ee ee ee ee eee ee ee eee ee ew Os 65 Me hs A

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watch, ltimeter t in the rge dial and the th dials flying. ApRIL, 1929 POPULAR SCIENCE MONTHLY 41 Mammoth Flying Hotel for 80 Passengers—A Rival «Question Mark”—Unusual Ideas and Inventions OLOSSAL flying hotels are re- rted nearing completion in Germany. Roomier and more comfortable than the Graf Zep- pelin, it is said, is a heavier-than-air Dornier machine for eighty passengers, now nearing completion on the shores of Lake Constance. Weighing fifty tons, it will be four times the size of any known airplane. Twelve motors, of which only six or eight will normally be used, will propel this huge plane designed by Dr. Claude Dornier, famous maker of great ying boats. ; Meanwhile, the Junkers works, in Ber- lin, is building an air liner in nautics has just completed a great tunnel twenty feet in diameter, whose 110-mile- an-hour whirlwind will test propellers and model wings of large size. A Helicopter That Works? LOSELY guarded from the curious, a strange flying machine is being built for the British government at Saunders Aircraft Works at Cowes, Isle of Wight. It is an improved type of “helicopter,” designed by the Italian inventor, M. V. Isacco, to lift itself vertically into the air. Flying straight up has long been the have proved so successful that a large shipment of the eyepieces has been or- dered, according to Dr. S. M. Burka, as- sociate physicist qualified in aerial photog- raphy at the Army field. Formerly, Dr. Burka says, many pilots refused to wear goggles because they caused headaches after prolonged use. With the aid of instruments that meas- ured the actual effect of a goggle lens upon the eye of the wearer, experiments were carried out to devise a new goggle that could be worn eight hours, left off for eight hours, or worn intermittently, with no loss in comfort. The result was a novel lens thicker on one side than at the other, instead of the flat sur- which fifty passengers will ride in the eight-foot-thick wings. A mammoth Consolidated sea- plane which will carry thirty-two passengers, when modified for commercial use, passed its first Navy flying tests recently at Anacostia, near Washington, D.C. Measuring a hundred feet from wing tip to wing tip, it is by far the largest flying boat in America, and is designed to compete with a ae SAN FRANCISCO. 4 wie " t \ r / / face that would be expected to cause least strain. Pilots tried it and liked it. Now the tapered glass lens has been combined with a frame to give the most vision with the least glass, and is being produced in quantity. Britain’s **Question Mark”’ MPRESSED by the recent six- huge new European flying boats. It was to foster the development of such a type that the Navy ordered the $150,000 monster. Now this type is reported being considered for service between Detroit, Cleveland, and Buffalo. $900,000 Wind Tunnel ULL-SIZED airplanes would be tested without flying them, in a $900,000 wind tunnel pro- posed in a bill recently reported by the House Appropriations Committee at Washington, D.C. The project calls for a tube of enormous size. Hitherto only the action of propeller and fuselage have been observed with full-scale parts, while test of a whole plane required the construc- tion of a miniature model. Since Orville and Wilbur Wright gave aviation the wind tunnel a quarter of a century ago—an invention largely re- sponsible for the airplane’s invention and its subsequent improvement—these tubes through which rush man-made gales have conserved lives and dollars while they have revolutionized plane design. For perhaps as little as $100, a satisfactory model of an untried type of plane may be built and placed in a tunnel, where it re- veals exactly how the finished plane will behave. No pilot need risk his life to take it into the air. The artificial hurricane that surges around the model from a powerful blower is sure to detect hidden flaws and suggest advantageous changes. The U. S. Bureau of Standards, at Washington, D.C., owns three such tun- nels, of three, four and a half, and ten feet diameter. In the smallest a blast of air moving at 150 miles an hour may be attained. At Langley Field, Va., the National Advisory Committee for Aero- C continental travel. dream of airmen; it would make landing fields unnecessary, and would hasten the day of the “‘flivver plane” for everyone. But such are the practical difficulties of constructing a helicopter that the U. S. Government has, for the time at least, abandoned experiments of this nature. A year ago, the inventor Isacco ap- proached the British Air Ministry with his design for an extraordinary helicopter —a windmill plane ,with a fuselage re- sembling the Cierva “‘autogiro.” But where the autogiro’s windmill revolves freely in the wind, without power, and consequently excludes it from being a heli- copter capable of lifting itself, the two large blades of Isacco’s windmill are fitted with individual motors and propellers which face in opposite directions. The theory is that the revolving horizontal vanes will lift the whole machine, which will travel forward by the usual propeller. New Goggles for Airmen RST tests of a new anti-eyestrain type of goggles developed by the Army Air Corps at Wright Field, Dayton, O., OVERED wagon—stage coach—rail- road—and now it’s the air-rail! This simple map tells the latest chapter of the amazing story of progress in trans- It shows the route of cross country air-rail service soon to op- erate on schedule. Passengers leaving New York in the evening will ride in trains to Columbus. Transferring to planes there, they will stop in St. Louis for luncheon and arrive the same night in Dodge City, Kan. Boarding a train again, they will ride to Las Vegas, N. M., and there take to the air and fly to San Francisco. day flight of the American plane Question Mark, refueled from the air, Britain is going after a few endurance records with her own “Question Mark” plane. A giant Fairey monoplane, just com- pleted, will attempt first to break the world’s nonrefueling record of sixty-five hours in the air; then it will be flown to Cape Town, South Africa, where it will at- tempt a nonstop return trip of some 8,000 miles—a third of the way around the earth—to London. The silver craft on which Eng- land pins her hopes is a stream- lined monster that measures eighty-two feet from wing tip to wing tip. Its extraordinary fuel capacity of 1,000 gallons in tanks concealed in the thick wings is expected to permit a flight of three days and nights without refueling, since the 450-horsepower Napier motor and the slim fuselage are designed espe- cially for economy of gasoline. A novel feature is a “hooter” that automatically utters a warning signal when the pilot de- viates from his set course. Two daring American proposals to fly nonstop around the world have followed the pioneer Question Mark’s flight. An eastward flight, starting from Paris and returning via India, China, Siberia, and the United States or Canada, is the proj- ect of the Fokker aviation firm with next June the month suggested. Tank planes stationed over various cities would refuel the globe-circler on the way. Meanwhile Col. Arthur C. Goebel, American winner of the Dole flight from California to Hawaii, plans a flight from west to east around the world, starting and ending at Wichita, Kan. He hopes to make the attempt in August or September. “~

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: 4 {ene ere patie eee: eee fe he eR aoe ne aA = Arm, 195) As be e a hers of Flichj : P t : r i How Wilbur and Orville Wright} j Climbed on Wings at Last—Th,e} * Stirring, Inside Story of the! / ° D 9 World’s First Powered Plane} 7 re By JOHN R. McMAHON , 0 th tr ct ne af th in ; > cl 4 Sp G : di ax Wwe . ’ Ww Uy ; | T wy te " ~ 4 2 sl Ww i: f ~ 4 i — o b Where the airplane was born. Y, s} View from Kill Devil Hill, at My Kitty Hawk, N. C., during i? the recent twenty-fifth an- & niversary celebration of the Wrights’ first powered flight. = =—— += E Orville Wright as he i = ez appears today, wearing NY - an aviator’s helmet, HUT! boom! Hut- re ia phut-tut! Bang! Like the huts of explorers in i re Bang! Arctic wastes—the Wright =a of flight and planned now to embody them ! A fat dozing po- camp at Kitty Hawk, 1903. = | in a power machine. They sought to buy liceman sprang quickly : an engine for the purpose and wrote to \ from his back - warming ~ =SY several manufacturers—in vain. chimney prop and swung his club wildly. Orville, a suitcase in “Haw, haw, letter from a couple d Dogs barked, a cat ran, small boys with ear muffs hurrahed, and shopkeepers in white aprons ran outdoors in the wintry air after their customers to find out the meaning of the terrible racket. ““*Tis a Jesse James holdup!” quoth the fat bluecoat, stalking warily toward the alley that led behind the office of the Wright Cycle Company, whence the noise emanated. Bluish smoke drifted from a shed in that alley. The murder, or what- ever it was, evidently was being com- mitted in the shed. “Don’t be afraid, folks,” proclaimed a pompous citizen. “No need for alarm. The Wrights always did make a lot of noise with their homemade gimmicks. This time they’re testing their own gas engine.” “Oh, a gas engine?” repeated several vaguely. “Bah!” snorted the policeman, dis- gusted, yet relieved. “‘Well, an engine ain’t agin’ the law, but I will say this one sounds drunk and disorderly!” Nobody in that Dayton, Ohio, crowd dreamed tha. the unmuffled barking, coughing, and backfiring was a noise each hand, trudged across the sandy desert. historical—a prelude to the hum of a myriad motors in the sky—the pristine song of the airplane engine! It was Lincoln’s Birthday, Feb. 12, 1903, that Wilbur and Orville Wright gave that engine its first try-out. After three years of gliding experiment at Kitty Hawk, N. C., and epochal research in aerodynamics at their Dayton bicycle shop, they had discovered the principles chaps in Dayton says they want a gas engine for a flying machine! Wastebasket, Miss Jones! Almost funny enough to keep! ...” While the brothers had built a two cylinder two-horsepower gasoline motor for shop power back in 1899, they were not too confident that they would succeed with a larger engine. Internal combus tion was yet a crude novelty, spark plugs were freaks, self-starters unknown. while before Christmas, 1902, the Wrights began work on their motor which was The Wright glider of 1902 had all the essentials of the modern airplane except a motor. Left to right are Octave Chanute, Orville, Wilbur, A. M. Herring, Dr. Ge-rze A. Spratt, and Dan Tete.

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APRIL, 1999 ight as he ay, wearing "s helmet. body them ght to buy | wrote to . . couple of ant a gas stebasket, nough to It a two ne motor they were d succeed - combus ark plugs 10wn. A e Wrights =h was to ApBIL, 1929 jader, eight-horsepower, with be four ght of 200 pounds. Water- a ling and magneto ignition were coo! ed. They made drawings and had lil into wooden patterns for the a sum of $22. The engine case of aluminum was cast at a local foundry but the machining was mostly done in the bicycle shop by the proprietors and their 7 employee, Charles E. Taylor. T ONE time Charley was regarded as a Sancho Panza who served two Don Quixotes. He looked after the bi- cycle trade when they were at Kitty Hawk, made whatever queer things were uired, was utterly loyal, nor) — the years as permanent a feature thro rights shop as “faithful Carrie,” the housekeeper, was in their home. They treated him with affectionate familiarity. Needless to say, Charley was a good me- c. ot the neighbors were scared by the noise of the new motor, its makers were afraid, too. The racket was worse than that of their boyhood creation of a turn- ing-lathe which had drowned out a cy- clone. ‘They noted a demonic engine speed of 900 revolutions a minute and did not imagine that twice as much speed would become ordinary. The horsepower was a little better than planned. Charley Taylor was sickened by the smoky ex- haust which filled the shed. Another test was made next day, when dripping gaso- line deprived the bearings of lubricant so that they “froze,” breaking the engine body and frame. After repair, the motor spurted to sixteen horsepower for a few POPULAR SCIENCE MONTHLY seconds but settled to a steady gait of twelve. If the pistons had been glass smooth and the other parts made to correspond, the engine with its four- inch bore and four-inch stroke would have had almost three times as much wer. “The Wrights flew because of their engine,” is an old bedtime story. “ You see, children, internal combustion gave us the automobile and then the air- plane.” Children, I assure you this is a fable. In the first place, the Wrights estab- lished the principles of flight without power and thereby made possible all- day motorless gliding, which promises further gorgeous development in free, birdlike travel. Then their motor was much inferior to the engines of their predecessors. “The Wrights flew in spite of their engine,”’ is the correct version of that bed- time story. The next job after the motor was to design pro- pellers. It looked easy. Simply take a water screw and adapt it to the _7 air. But the brothers learned with surprise and chagrin that there was no help for them in marine screws, which after half a cen- tury of use were shaped by rule-of-thumb instead of sci- ence. Even a dozen years after this date, Orville Wright pointed out to me that the steamship Caronia of the Cunard Line was then changing its propellers in the hope that a new style might perhaps Charley Taylor, mechanic who served the Wrights for years, and helped build the first plane. yield a little more push. Sir Hiram Maxim had got nowhere with his tests of numerous tiny propellers of all kinds of shapes. Pro- fessor S. P. Langley of the Smithsonian Institution had mounted an air screw on a flat car which was whisked over a track half a mile long. He obtained a dusty answer. The Wrights learned from a marine authority that almost any guesswork screw would be fifty percent efficient and at first they were inclined to try the recipe. Then they resolved te tackle the problem with sci- They ran in often to warm them- selves over their carbide can stove. ence. They saw that the blades of a propeller were curved sur- faces like those of an airplane wing, although the former moved in a circular instead of straight path through the air. A screw is a wing, yes, but it travels sidewise, at the same time advancing and also kick- ing the air backwards. How can you apply the formula of the wing table to a compli- cated, ornery, multiple-ac- tioned, logarithmic, mean, and mulish pest of a propeller? RCHIMEDES moaned for a fulcrum to support his world-moving lever. The Wrights yearned for a fixed a i Orville’s model kitchen at Kitty Hawk, 1903. As ief cook, he sorted everything mathematically. Incidentally, he invented a French drip coffeepot. \} I Yi | The Kitty Hawk ’ | camp, 1902, showing glider of 1901, right. point whence they might begin calculations. We can imagine their fervent cry: * “Give us the angle of inci- dence at which the screw blades hit the air and we will do the rest!” Nobody in the world was then donating angles or any other useful data on flying, so the brothers buckled down to help themselves. In earlier stages of their in- vention they had held long and vigorous debates, each fighting the other’s position with all his might, so as to arrive. at truth. But no previous debate compared in intensity and duration with the ene 7 > ~—S See aetna at en

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POPULAR SCIENCE MONTHLY ree, December 17, The first airplane flight in history, with Orville aboard, flew 100 feet. APRIL, 1999 The bucking glider hitting Wilbur on the head tubes in which ¢ ran with slight frie tion. The transmis sion loss by chaia drive, instead of having SCTeWS gy engine shaft, wa figured by the mak. ers at five percent, A shop test ¢ engine and trans mission, with fans substituted for pro. pellers, was made in May and _ showed the first two feg. tures satisfactory, 1903. The machine, cote ? Since the motor had more than its ey. pected power, it was planned to increay the total weight o the airplane with its operator from 6) to 750 pounds. The added weight wa; put into heavier o strengthened parts T SEEMED the pioneers that a machine so mas sive, four times a heavy as a glider having the power d a dozen horses o more than one hu. dred men, would need to be exceed. ingly strong. So they braced and for. In a gale which nearly wrecked the camp, the brothers saved the roof. now begun. In the scant-ceilinged living room of their simply furnished home on Hawthorn Street and in the little bed- rooms upstairs, they hurled angles, sines, and tangents at each other. The argu- ment excelled the talking marathon rec- ord of Congress, for it went on for days, weeks, then months! Their sister Kath- arine—who with their father completed the household—was at first a fascinated auditor. She hastened home from teach- ing a high school class to hear another mystifying set-to in a region of rarefied science. She lost her zeal to listen and stopped coming home early. The brothers were getting tired also. Their nerves be- came frazzled. Screws in perpetual mo- tion spun within their throbbing heads. “TF YOU don’t stop arguing I'll leave home!” cried the exasperated, almost hysterical Katharine one day. It was a sobering shock. They cared more for their sister than for all science. Their fevered minds were cooled by the ultimatum, and—presto!—they saw the solution of their problem and knew how to design a propeller according to the formula of their air tables. A single screw has a gyroscopic effect that tends to hold an airplane on a fixed axis and to resist sicering, so it was de- cided to have two propellers whirling in opposite directions. Each was made of two lengths of two-by-four spruce glued together, shaped with a drawknife and other tools, often calipered to meet the dimensions of the mathematical pattern. The twin blades were eight and a half feet long and six inches in width at the tip. Half a dozen years later the world’s pilfering copyists were puzzled whether to use one, two, three, or four blades on a propeller and had no idea how to obtain the correct pitch. The Wright screw was fixed to its shaft with a sixteen-inch metal strap, wood screws, and a portion of the ever-ready shop panacea of the inventors—bicycle cement. It stuck for them and they stuck by it to the last aircraft they built. But it was a problem how to connect motor with shaft. Belts and locally obtained ‘chains were a failure. Then an Indian- apolis firm supplied a sprocket chain that was satisfactory and was used by the brothers ever afterward. ie ORDER to give one propeller a motion in reverse of the other, one chain was made to cross itself like a figure eight. Doubtless this was a crude expedient as later pointed out by Lillipu- tians of refined mechanics. The bare chains flapped, rollers were not a success, and finally the chains were cased in metal Memorial tablet recently unveiled on the site of the first airplane flight. At the left is Orville Wright. With him are U. S. Senator Hiram Bing- ham, of Connecticut, and Amelia Earhart, first woman to fly the Atlantic. tified and had lib eral factors of safety beyond the calev lated strains on every part. They did their best with wood and commo metal, lacking vanadium steel and dun lumin. It is noteworthy that no Wriglt machine, experimental or finished modd for the market, ever failed through pre ventable structural weakness—a _ reconl unique and an example in conscientiow workmanship. The inventors started on their history. making fourth-year trip to Kitty Hawk on September 23 and arrived two days later at their old camp near Kill Devi Hill, the largest of several dunes on4 sandy strip of wilderness between Albe marle Sound and the Atlantic Ocean. HE next day Orville wrote a joculat letter to “Dear Swes”—his iste Katharine—saying everything was in fait shape and reviewing the past marvels d Kitty Hawk, from a 107-mile-per-how wind that had torn away the anemomettt cups to the hordes of mosquitoes thal dimmed the sun and the lightning that made day out of night. Orville also statel that he had worked about half a day de vising a French drip coffeepot whieh would obviate the use of eggs for clearing the beverage, a worth while endeavor i view of the local egg scarcity. At th end of the amusing missive it occu to the writer to add that the new camp building was (Continued on page 156)

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APRIL, 199 ie reg n which ¢ th slight fric. SS by Chain Instead of Screws On shaft, Was by the Inak. ive percent, and trans 1, with f uted for pro , Was made jy and showed st two fey. satisfactory, he motor had than its e. power, it was d to increase tal weight of plane with its or from 60) pounds, The weight wa; to heavier o hened parts pioneers that hine so mas. our times a as a glide, the power n horses o han one hun. men, would o be exceed. strong. So -aced and for. and had lib tors of safety 1 the calcu. strains on part. They and common -el and dur at no Wriglt nished modd through pre ss—a recorl conscientiow their history: Kitty Hawk ed two day ir Kill Devi dunes ons tween Albe ic Ocean. ote a joculat *—his sister 1g was in fait ‘t marvels d nile-per-hout anemometet quitoes that ghtning that le also stated alf a day de eepot which s for clearing endeavor if ity. At the . it occurred ie new camp lon page 156) Apnit, 1929 Witches — Still on How the Human Mind, Miracles, Manufactures Them and Deceives Itself Craving By ARTHUR A. STUART “Charms against the evil eye.’’ Part of the paraphernalia of a Hungarian witch-doctor. WO hundred and thirty-seven years elapsed between America’s two famous witchcraft trials. As a result of the first, the “witches” were hanged; as a result of the second, the people who killed the professed witch, or “hex,”’ were sentenced to life imprison- ment. The legal point of view about witch- craft has changed. Early in 1929, to the amazement of every intelli- gent person in the civilized world, a brutal murder in York County, Pennsyl- vania, revealed that the be- lief in witchcraft still per- sists in the United States. John H. Blymyer, a “pow- wow doctor ” or practitioner of so-called witchcraft; Wil- bert Hess, a boy of eighteen, and John Curry, fourteen, were arrested on the charge of having murdered Nelson D. Rehmeyer, another “hex” or witch-doctor. They had gone to Reh- meyer’s house to see witch- craft performed, and Curry, at Blymyer’s instigation, killed the old “hex” with a stick of wood because he was “hexing” Blymyer. A Blymyer and the Curry boy were sentenced to life Imprisonment, Hess to a shorter term. typical witch, called zony’—a peasant wom- Hungarian an dealing in magic herbs. There’s the black cat, umbrella, and all. POPULAR SCIENCE MONTHLY Among the primitive tribes in the wilds of New Guinea, witchcraft is still practiced. This photograph shows four native witch-doctors in weird garb, casting their magic spells. In Salem, Mass., in the winter of 1691- 92, several hundred women and girls were arrested and charged with practicing witchcraft. Nineteen of them were hanged, after trial and conviction, on no other charge than that of being witches. One man was pressed to death under a heavy door for refusing to plead to a similar accusation! Everybody believed in witch- craft in 1692; only the ignorant ~ and uncivilized believe in it now. But as three quarters of the world’s population is still. igno- rant and uncivilized, it may fairly be said that belief in witches is still widespread. The witchcraft believed in and prac- ticed in York County in 1929 derives straight from Europe, whence it was brought by German settlers who came to Penn- sylvania in the eight- eenth century. The Salem witchcraft, however, was of American origin. Tituba, a West Indian slave owned by the Rev. Samuel Parris, minister of the Salem village church, taught ten girls palm- istry and sleight-of-hand tricks as practiced among the Carib tribes, and talked so much about the magic powers of the “‘medicine men” of his native island that the girls, the oldest of whom was seventeen and the youngest nine, swallowed the witch- craft idea whole and accused Tituba and two old women “* javasas- cine man was practicing his spells in the province of Amur, northern Siberia. whom they disliked of having bewitched them. The old women and Tituba were hanged, and the whole village caught the witchcraft infection. Everybody who disliked anybody else hurried forward with an accusation of witchcraft, often to be accused in turn of having caused a farmer's cows to go dry, or of making midnight flights on a broomstick to do injury to someone far away. The essence of witch- craft is belief in the ability of a witch to in- fluence others by super- natural means, to cause death or illness, bring enemy’s crops, or change babies in their cradles. It is found in all early religions. The ancient Jews believed in witches but did not tolerate them. The Christian church held to the belief in witchcraft for cen- This present-day medi- turies. The Church it- pe self undertook the pun- ishment of witches. There were executions for witchcraft in England long after the Salem trials. Many scientists have attempted to ex- plain the prevalence of the belief in witches. Students of the subject generally agree that the witch usually believes in his or her own powers. The idea that hypnotism and the power of suggestion, still only vaguely understood by psy- chologists, have actually been exercised by so-called witches, is accepted by many. The term “hex,” used by the Pennsyl- vania Germans to designate a witch, derivesfrom the (Continued on page 138) lovers together, blight an_

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A tn ll 46 By KARL VOOGHT HE daily news bul- letins telling of the grim battle for the life of King George V. of England drew world-wide attention, not only because the ruler of an empire lay near death from pneumo- nia, but because at his bedside were gathered perhaps the greatest force of diverse sci- ences ever focused on one task. Most of us, in case of illness, usually consider we have done the utmost when we call in the doctor. But to restore King George to health, it was deemed necessary to depend not only on the physician and surgeon, but also on experts in other lines—the bacteriologist, the biochemist, the X-ray physicist, the physiologist. They combined their knowl- edge in a concerted attack, with the result that at this writing the King was slowly mending. They demonstrated what science can accomplish by teamwork. The day is pass- ing when a single specialized branch of science attempts to achieve results alone. In in- dustry the problem of the engineer, for example, has be- come a problem also for the chemist and the physicist. In the same way the war on dis- ease is enlisting research workers in many fields other than medicine. According to Dr. Charles H. Herty, of New York City, every year more than 100,000,000 people suffer from various kinds of sickness, representing an eco- nomical loss of billions of dollars. What is needed, he believes, is a permanent alliance of the branches of science to improve health conditions. A bill, recently introduced in the Senate of the United States, would pro- vide a national institute of health, headed by a grand council of experts represent- ing and focusing the different sciences on the conquest of disease. Such codpera- tion would win battles that medicine, fighting lone-handed, would lose. Five Million Volts! ITHIN a quiet building in Pitts- field, Massachusetts, a group of men are experimenting with the world’s most dangerous plaything. It is a §,000,000-volt thunderbolt of laboratory lightning. Only once before has an at- tempt been made to produce such voltage. This took place a few months ago, during a spectacular experiment at the Carnegie Institution, Washington, D. C., and was described in Poputar Scrence MonTHLy. At the Pittsfield high-voltage labora- POPULAR SCIENCE MONTHLY Rescued from the Tree Top It was a lucky day for Thomas Hatton, a student pilot of Scranton, Pa., when his plane crashed into a tree top at Cincinnati, O. Not only did he escape injury, but a hook-and-ladder company was there to bring him down, and a photographer was on the spot to take this unusual photo- graph of the rescue. Accidents such as this are becoming fewer in number, thanks to better airplanes and improved guides for pilots of the air. tory of the General Electric Company, four generators, each producing.a million and a quarter volts, were hooked up to- gether. Their combined discharge is one twentieth as powerful as the actual bolts that streak across the sky during thunder- storms. Various uses have been suggested for these record artificial lightning flashes. In one experiment, they will be flung at model transmission lines within the labo- ratory to discover new facts about the effect of lightning on high-voltage wires. In recent years, experimenters have measured electrical pressure up to 10,- 000,000 volis. They have discovered the EHIND every important new discovery or inven- tion lies a story. Behind ‘hard-sounding technical names and phrases usually can be found a wealth of won- der, adventure, and under- standable knowledge. You’ll enjoy the little stories which make up this feature each month. And we believe you'll find them valuable in adding to your store of information. length of time it takes a cloud to discharge its electricity ag lightning. Recently an Austrian scien. tist estimated the value of the power wasted during an eles. trical storm. It would cost a million dollars to put on a fey minutes of Nature’s hea electrical fireworks, with fre. quent flashes of lightning, By learning the secrets of these lurid flashes through labors. tory experiments, science hopes someday to capture their waste electrical power and put it to work. Poison in Comets YANOGEN, one of the most deadly of all poisons, recently was discovered in the heads of comets by Dr. N, T. Bobrovnikoff, of Lick Obsery. atory, by means of a spectro. scope. He found also that the comet’s tail is almost equally dangerous, for it is full of carbon monoxide, the same deadly gas which is given of by an automobile exhaust. These discoveries are of par. ticular interest because comets have always been regarded by primitive men as portents of evil. Even down to very re cent times the appearance of a comet has been sufficient to send whole communities, even nations, into panic. Milton, in Paradise Lost, says of a comet that “from his horrid hair shakes pestilence and war.” The comet was a mysterious stranger, upset- ting the orderly procession of the stars in their courses, and might bring dire disas- ter in its trail. Were primitive peoples afraid of comets merely because they were terrifying spec- ters in the skies, or did the tail of a comet once brush close enough to the earth to poison a considerable proportion of its inhabitants, the tale of which catastrophe, handed down through countless genera- tions, gave rise to the belief that comets are messengers of evil? Nobody knows, any more than science can tell today, how the cyanogen gets into the comet’s head and how cyanogen is converted, as it seems to be, into the carbon monoxide of the comet’s tail. Dyeing the Blood to Keep You from Dying NEW scientific offensive has been launched at Stanford University, California, where two chemists are pump ing dyes into the blood of rabbits, pig- eons, and guinea pivs as a remedy for diphtheria, ptomaine poisoning, snake bite, and other diseases and poisons. TLrough their tests of small animals, the chemists, Professors Butt and Hanzlik, expect to determine whether human be | — _ee — hn es i tet lO OlU SS

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APRIL, 1929 /W§ takes a cloud electricity as ustrian scien, > value of the Ting an elec. would cost g put on a few ‘ure’s heg ks, with fre. ightning, By ‘ets of these ough labora. its, Science to capture a power Comets one of the f all Poisons, vered in the y Dr. N. 7 ick Obsery. f a spectro. ilso that the nost equally - is full of _ the same IS given of »xhaust, s are of par. ause comets regarded by portents of to very re. pearance of sufficient to nities, even c. Milton, says of a his horrid var.” The ger, upset- the stars in dire disas- 1 of comets fying spec- of a comet e earth to ‘ion of its tastrophe, SS genera- iat comets an. science ogen gets cyanogen , into the ; tail. Keep : has been niversity, re pump bits, pig- nedy for g, snake poisons. mals, the Hanzlik, man be- April, 1929 . i nd to the same treatment. ings ive fed a rabbit enough strych- . nd kill an ox, then saved its life by laaias” Congo red into its veins. 7 ns similarly inoculated with cobra hon guinea pigs with diphtheria je "and rabbits with ptomaine poi- eee all have been restored to normal the color treatments. TT Congo red has proved the most effective dyestuff remedy. _It seems to s peculiar properties in combating POPULAR SCIENCE MONTHLY 47 failed to express the interest with which electrical and construc- tion engineers are wait- ing for complete re- ports on the condition of the little vessel, which is only 150 feet long. For the Fullagar was the first ship in the world to be fas- tened together entirely isons that seep into the Te Thus the dyes, or “paints, ” act as strong and efficacious antidotes, enabling the white corpuscles of the blood—the real healing agents of the body—to battle vic- toriously against the bacteria that threaten to overwhelm them. The California chem- ists also hope that their dis- covery eventually will enable medical science to prolong human life by eliminating from the blood the poisons that cre- ate many old-age ailments. Oil for Auto Fuel YOUNG inventor from New Zealand, Ernest Godward, recently brought to America a device which he thinks may save bus owners in this country $50,000,000 a vear. His invention enables the ordinary gasoline motor to run on cheap fuel oil, such as is used in oil-burning furnaces. Twenty Philadelphia buses have been equipped with the invention and have run nearly 300,000 miles over steep, hilly roads. Six hundred additional i Sale To i. 2. | me =— om fs de oe om me | ee —_—_— | oe i ee ae PE ee Sg fs os interurban buses of that city are being fitted to burn the heavy oil. Motors burning the new fuel are said to start as quickly as when using gasoline and to show an increase of as much as fifteen percent in horsepower. Unlike Diesel en- gines, motors equipped with the Godward device can use either oil or gasoline. The invention is described as an alu- minum pot in which is set a nest of stationary, thin, curved plates radiating from a central core. This pot is heated by the exhaust. The oil, drawn through a carburetor, passes over the surface of the warm plates, where it is converted into dry gas before reaching the cylinders. The inventor designed a simple ap- paratus to test the efficiency of motors. It measures the unburned gas coming from the exhaust pipe. In other tests, airplanes were operated on heavy oil instead of gasoline. And Dr. Joseph S. Ames, of the National Advisory Commit- tee for Aeronautics, predicted in Poputar Science Monruty that eventually special Diesel engines burning the less expensive fuel might be installed in planes. Why Not Weld Them All? RECENT little newspaper item, which told of the over- hauling of the British ship Fullagar, Study X-Rays Behind Barricade Piles of sandbags and a concrete wall between operators and machine are used at California Institute of Technology, in Pasadena, to absorb the dangerous offshoots from powerful X-rays generated by 1,000,000 volts of electricity in a fifteen-foot tube, the world’s largest apparatus of its kind. The sandbags and wall prevent the rays from injuring Prof. C. C. Lauritson (left), who designed the tube and its protective barricade, and Prof. E. C. Wat- son, who aids him in operating the machine. Running Motor Buses on Fuel Oil J. A. Queeney, vice president of the Philadelphia transit com- pany which is equipping its motor buses to operate on heavy fuel oil in place of gasoline, points here to the new invention which makes it possible. The device is a series of thin metal plates heated by the exhaust. The oil, drawn thrcugh the car- buretor, passes over the surface of the plates, where it is con- verted into a dry gas before reaching the cylinders. The fuel, it is claimed, is not only cheaper than gasoline but more efficient. Testing with Mechanical Hands One of the newest testing devices. of the U. S. Bureau of Standards, Washington, D. C., is this odd looking machine which measures the accuracy and durability of hand numbering machines used in business offices to number pages and documents. Weighted motor-driven rods push down on the handles of eight numbering machines, whose im- pressions are recorded on the paper rolls seen be- low. These impressions show how each machine stands up under the continued pounding, as well as the accuracy with which it prints the numbers. by electric welding of the steel plates instead of rivets. Reports indicate that in her eight years at sea, she is in much better shape than most riveted ships after that length of service. The layman wonders why all steel- frame buildings, bridges, ships, and tanks are not constructed by this_ noiseless method. One of the reasons is that in many cities the building codes do not permit it; it is too new and untried, the authorities believe, to justify risking the collapse of a skyscraper. Also, many construction engineers and contractors, having riveters available, are reluctant to bother to teach them to use electric welding apparatus or to experiment with men skilled in electric welding but un- trained to work on the skeletons of sky- scrapers. Nevertheless, eighty-five different structures so far have been put together by electric welding in different parts of the world, the largest of them being the fifteen-story steel frame addition to a Detroit depart- ment store. Eight bridges and a number of barges and tanks also have been so constructed. The latest application of electric welding is by the Delaware and Hudson Railroad, which is making its crossties for switches and cross- overs out of metal instead of wood, using worn-out rails cut to tie length for this purpose. The cost is less than that of wooden ties and the life much longer. As the rail- roads of the United States have to replace some 30,000,000 ties a year, it would seem that welded steel ties would be a great economy. On main line tracks, however, metal ties are not practical, interfering with electric signal systems by making a metallic connection be- tween the rails. Efforts are now

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48 being made to devise an effective insulat- ing system that will make the use of metal ties feasible on all sorts of railroad tracks. Benjamin Franklin’s Broom NE of Benjamin Franklin’s contribu- tions to science, heretofore unnoted, was disclosed at the latest annual meeting of the National Broom Manufacturers’ Association, where an old diary was quoted, telling how a woman of Frank- lin’s acquaintance had sent him a whisk broom from India and so enabled him to establish the broom-corn as an American farm product. There were some seeds in _ the wisps of which the broom was made and Franklin, always curious about everything, planted them and distributed their seeds, in turn, to others. Many plants which we are accustomed to regard as native to America were thus imported, purposely or by accident. Thomas Jefferson introduced the upland rice into the South, as well as many other European crops. The early New England colonists brought their own seeds for planting. Almost the only contributions America has made to the agricultural resources of the rest of the world are the potato, tobacco, and maize or Indian corn. Cotton was brought to America from Africa, and so was the sweet potato. Wheat and all of the other small grains came from Europe. All of our domestic fruits except the cranberry, huckle- berry, and possibly the grape, are im- portations from foreign lands. Florida’s wild oranges started from orange seeds brought by the first Spanish explorers. The wild cattle of the Southwest are all from Spanish stock, similarly brought over in the sixteenth century. Horses were un- known on the American con- tinent until the Spaniards brought them; the Indians ‘had no domestic animals ex- cept dogs. All of our domestic fowls except the turkey came from overseas; the turkey is a native 100-percent American. Key to Long Life ? R. F. G. BANTING, Canadian discoverer of insulin, used in the treatment of diabetes, is going to in- vestigate the life-prolonging possibilities of “royal jelly,” the food provided for the queens by worker bees. This substance pro'ongs the life of the queen bee for several years, and Doctor Banting hopes to discover something that can be used similarly for huma beings. Such medical research is important because more and more people are con- tinuing their activities through advanc- ing years, and eminent physiologists re- cently have declared that the brain does not grow old but continues to function with increasing power to the end of life. Old age is a matter of the condition of the body tissues rather than of years, and its onset varies with individuals, according to Dr. Alexis Carrel, of the Rockefeller Institute for Medical Re- POPULAR SCIENCE MONTHLY APRIL, 19 BS Re NS Ae ee eA RN in 4g PATS » oldest known living thi onies of bacteria recentiviaan Prof. Charles B. Libman of b University of California. te up in rocks which date back the Algonkian Age, supposed have been somewhere from . hundred million to two hundrej million years ago. The cond. tions under which these. were found, in rocks from hundreds of feet below surface, preclude the suggest that they are of later develop, ment than the rocks themselye These bacteria multiply by division, each individual se ing into two parts, which, iy turn, divide and continue to do so indefinitely. What Is the Right Size? F A man were sixty feet hi couldn’t walk. That oe couldn’t walk without break his thigh bones, which will . port only about ten times one; weight without breaking. If yo multiply one’s height, width, anj thickness each by ten the tot, weight will be multiplied by, Tells How Wind Sways Towers Rocked by a gale blowing seventy miles an hour, this model of a steel water tower will reveal wind pressures and strains to engineers of the U. S. Bureau of Standards at Washing- ton. The model, shown here with Byron H. Monish, a Federal expert on winds, is placed in the Bureau’s huge wind tunnel to prove how it can stand up in a gale made to howl around it. The World’s Healthiest ‘‘Spuds”’ Uncle Sam’s plant experts in the U.S. Department of Agriculture have developed a new variety of white potato which, they say, is immune to most of the diseases and blights that prey upon America’s tuber crop. Dr. William Stuart exhibits here a few of the world’s healthiest “‘spuds’’ he helped to grow. “Black rot’’ holds no terrors for them. search, who, in his remarkable experi- ments, has kept muscles of a chicken’s heart alive for nearly twenty years. He told the New York Academy of Medicine recently that the physiological age of any person can be readily determined by examining certain cells from the blood. Tests of this sort may yet be adopted by insurance companies, employers of labor, and others to determine whether a man is actually younger or older than the color of his hair and the date on his birth certificate indicate. But to whatever limit the efforts of science may prolong human life, the longevity record will continue to be held by lower forms of life. The simpler the structure, the more durable it is. The thousand, but the cross sectigg of each bone is multiplied by a hundred, so that each bom has to carry ten times as much strain as in the normal individual, That is the ingenious way iy which J. B. S. Haldane, famoy English biologist, disposes of the giants of folklore and myth. They couldn’t have existed and rm mained human, he says. If they were shaped differently they wouldn’t be human, and they would have had to be shapel differently to have lived. It is easy to imagine an insect the siz of a man, for example, but such insects not only do not exist but cannot exist, Insects absorb oxygen through ther skins or shells instead of breathing through lungs. Multiply the mass ofa grasshopper by a thousand—that is make it ten times as large in each dimen sion—and you have only increased its surface or skin area by a hundred. To support life it will have to absorb oxygen ten times as readily through its skin it actually does or can. The surface area of any body does net increase with the increase in the body's weight or mass. A man stepping out d his bath brings with him a film of wate of a definite thickness, weighing only about a pound. A mouse falling intos pan of milk is covered with a film of the same thickness, but which weighs almost as much as the mouse itself. Insects getting only part of their body wet ar helpless. Watch a fly which has beet submerged in water. It cannot fly until it has dried off. A small animal can fall a hundred fee or more without injury, its bones are # much larger and stronger than those @ larger animals, in proportion to its size The fabulous roc of Arabian myth, the bird which was large enough to pick up# man and fly away with him, could no have existed; it would have had about all it could do to fly away with a lamh

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multiply }, ‘idual mt ‘ ts, which, jy ontinue to dy ight Size? ty feet hi That it i out break; hich will sup. n times one; uking. If you it, width, and ten the total Itiplied by.a CTOSS sectiog ultiplied iat each bom mes as much al individual, nious way i dane, famous a of the myth. ted de says. If they rently — they n, and > be shaped ived. nsect the siz such insects cannot exist, rough their f breathing 1e mass of 4 nd—that is, each dimen- increased its tundred. To sorb oxygen h its skin a ody does net n the body's pping out d ilm of water sighing only alling intos a film of the eighs almost elf. Insects ody wet ar ch has beet not fly until 1undred feet bones are 80 ian those d 1 to its size 1 myth, the to pick up# 1, could not _ had about rith a lamb est condors of the Andes have seal to do. Give a bird a body as big a8 @ man and it would have to have a keel four feet deep on its breast- pone to attach the huge muscles which wo .d be needed to flap its enormous ture’s way of compensating for the disadvantages of being large or small are through changes in the surface or of the breathing and digestive organizations. The larger the animal the more com- licated its internal systems. Unless shape changes with size, increase or decrease of size puts an animal out of the running, his species out of existence. wings. Na New Wonders in Glass LASS is not nearly as leakproof as i most of us think, a to fessor G. P. Baxter, Dr. H. W. Scbeveather, and Dr. R. B. Ellestad, of Harvard University. They sealed about a quart of helium gas in a globe of fireproof glass. After a year and a day they found that a little more than one percent of the gas had escaped through the tiny pores of the globe. Although the Egyptians, more than fifty centuries ago, discovered how to fuse glass by applying heat after mixing eommon sand chemicals, almost each month new discoveries increase our store of knowledge regarding it. Now it can be made so tough that a bullet from a forty-five-caliber pistol, shot from a dis- iance of ten feet, will glance off. It can be made so that it will bounce, bend, pour like water, even be sawed like wood. Austrian scientists have perfected a way to make it flexible. Glass wool, a fluffy stuff that looks and feels POPULAR SCIENCE MONTHLY has hardly any electrical effect. But when other influences begin to stir it up, many of the atoms become ionized, which means that they are split up into elec- trical particles. These conditions prevail most of the time without interfering with Bolt of Iron Cast from the Sky Australian kangaroo hunters stumbled upon this 1,400-pound - meteorite which had plunged from the sky in the vicinity of Queensland. Brought to America and analyzed, it was found to contain ninety-three percent iron, some nickel and platinum, Dr. Oliver C. Farrington (left), curator of geology for the Field Museum in Chicago, is shown here with an assistant, studying the huge meteorite. and particles of other minerals. like silk, is ordinary glass spun into threads so fine that it would take 2,800 of them laid side by side to make a one- inch ribbon! Glass really is an oxide of a metal and is commonly made from a fusion of oxide of silicon with another metallic oxide, such as the oxides of boron, soda, or iron. Such is the magic of glass that to begin to list even the most common necessities it supplies would be an end- less task. Without it we could have no incandescent lamps, radio tubes, nor many other wonders of modern science. Radio’s Puzzles HE United States Bureau of Standards recently an- nounced that radio engineers confess being baffled by the problem of static. Behind that announcement lurks oppor- tunity. The inventor of the really effective static elimi- nator can become a multi- millionaire. What is static? The lower portion of the atmosphere, which we call the air, and in which our radio broadcasting is done, is a gas. It consists of molecules and atoms of various elements suspended in *great-mixture. So long as it is quiet and free of water, it Fresh **Milk”’ Right from the Bark ‘Cow trees’’ recently discovered in the Puerto Barrios district of Guatemala by Prof. Samuel J. Record, Yale University forestry expert, give milk that looks and tastes like the familiar dairy product and is said to be highly nutritious. trees by gashing the bark. They use the “ milk’’ in coffee. This picture-shows how natives “milk’’ the 49 yow radio reception. It is when the ionization is localized and sporadic, as for example when a thunderstorm is brewing, that the notes of the sweetest sopranos are drowned and the most persistent lecturers choked off. Static, however, is not the only un- solved radio problem. Engineers through- out the world are trying to find the answers to many other questions. They don’t know whether transmis- sion from east to west differs from that in the opposite direc- tion; whether there is a wave length limit beyond which trans- mission over land is virtually identical with that across water; whether waves above a certain frequency fail to return to the surface of the earth. . Radio, though it talks a lot, is still in its early infancy. Im- provements aplenty are to come, and each one of them will mean a fortune for its inventor! An- other problem is fading. Why do signals come in strong, then fade away periodically? Many fine-spun theories have been ad- vanced, but no proof or remedy. Why Sap Rises HE mystery of the rise of sap which has puzzled scien- tists for years apparently has been solved. Dr. D. T. Mac- dougal, of the Desert Labora- tory, Tucson, Ariz., recently announced his discovery that the sap is hoisted by the leaves to the tree top from above, not pushed up by the roots, as experts long believed. And this can happen, he explained, because water, strangely, is as strong and “unbreakable” as manila rope or some metals. The leaves of the tree evaporate water. A tension is created at the top of the sap tubes in the leaves. An “un- breakable” column of water is pulled up from the ground through the roots and the trunk by way of a complicated net- work of tubes and passages. To understand the strength of this column of water, fill a small glass tube with water absolutely free from air bubbles. It takes a pull of more than a ton to the square inch to tear such a water column apart. Water, by this test, is about as strong as manila rope, which requires a pull of about a ton and a half to the square inch to break it. It is so strong that it sticks together with more than ten times the tenacity of Portland cement! : Imagine the columns of sap that fill a tree’s tubes as so many metal wires. When the top is pulled the wires are hauled up. This an ingenious machine called a “‘dendograph”’ proves by measur- ing the girth of the tree trunk. During the day, when the sap is rising, the trunk shrinks, due to the pull. At night -it swells as the tension is released. If the sap were pushed up instead of being hoisted, the opposite would be true. Until recently scientists have believed that force pumps of some kind in the tree’s roots raised the sap. Now it ap- pears that the true explanation has been found.

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ee POPULAR SCIENCE MONTHLY So ey Toe auto manufacturers in his whirlwind Baker ee Broncho Buster’ Tells His Story to HENRY MORTON ROBINSON tain-climbing records than any man who ever lived. For (C tsin-climbin BAKER holds more endurance and moun- twenty-three years he has daringly tested the products of *‘road laboratory”’ of actual performance, speeding in all weathers over all kinds of roads, taking chances only with his own life. Here he relates the most thrilling of death-defying adventures which have crowded the lifetime he has spent in making valuable con- — ee ee ae OANA AOS A IS iat El te . En OO VE charioted across North America exactly ninety-three times! The first time with twenty-eight blow- outs and three breakdowns. The last time with not a single tire change or mechanical adjustment of any kind. When you stop to think about it, that’s just about the history of auto- mobile and motorcycle development in this country. My mounts have ranged from the sputtering one-cylinder motor- bike with which I made my first trans- continental run in 1911, to the mighty 110-horsepower sportster of 1928. For the past twenty-three years I’ve pushed all makes and models over desert trails, mountain passes, and gully bottoms— taking everything that came in the day’s run. And it was a pretty tough run, too. I grew up in a racing town. Indian- apolis, the city that made automobile road-racing famous, was just beginning to hold its speed tournaments when 1 lived there as a kid. One of my earliest memories is squeezing in at the wind-up of a road classic, in which Harry Payne Whitney, the winner, had recorded an average of 43 miles an hour. Second prize went to a youngster named Barney Old- field, who came roaring home at the terrific speed of 42.6 miles. Anything better than a mile in 2.20 seemed a break- neck pace in those days. The bicycle craze was at its height just then, and naturally I had a wheel—an old Pope-Hartford. Until I was sixteen years old I was satisfied to pedal around with my own leg-power. But when I went to work in a machine shop a year later, I saved enough money to buy a tributions to the science of better automobiles. portable motor, rated at three-quarter horsepower, and attached the con trivance to my “ice wagon.” The effect was dizzying! On a trial spin, I passeda fire engine going nineteen miles an hour, and began to regard myself as the coming race driver of the U. S. Sometime later I secured a secondhand Indian, tinkered around with it till I got it up to thirty an hour, and began looking around for an opportunity to break into the motorcycle racing game. My chance broke with dramatic sud- denness. A traveling fair came to town when I was about nineteen, and I heard there was to be a motorcycle race on the old trotting track. With some vague notion of entering my one-lung Indian, I strolled down to the grounds and found the Big Boss in a steaming rage.

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er” pun- For ts of 9 of inds lates have ron- e-quarter the con- The effect passed a an hour, e coming ime later tinkered thirty an d for an otorcycle atic sud- to town | I heard e on the e vague - Indian, id found Illustrated by B. G. Seieisiad “A vicious blow-out twisted the handlebars out of my grip, my machine whizzed from under me, and I was catapulted through the air, landing in the middle of the track.’ “Run over to the local garage,”’ he was shouting at a stake-man, “and see if they've got anyone that can ride a motor- evcle. ‘Red’ Nelson’s off on another jag, and we haven’t anyone to take his place in the exhibition race.” My career as a racing driver dates from that moment. I stepped out onto the track and announced myself. “I’m pretty good on a motorcycle,” I began. “Ever work with a_ twin-cylinder Indian?” he asked, surveying my lanky six-feet-two. “Sure,” I lied. “I’ve been repairing an Indian for two years.” (Which was true.) “Then warm up that machine and stand by for action.” [ lugged the red monster out onto the track, and for the first three laps I almost coliapsed from heart failure. The old bike had a handlebar throttle, the first one I'd ever seen, and when I went around corners I’d unknowingly twist the throttle wide open in my attempt to stay on the track. From the grandstand the effect must have been wonderful—but to this day I don’t know why I didn’t kill myself going around those corners. When I finally brought the old boat to a halt, the Circus Boss wiped a moist brow and asked me my name. “Erwin Baker,” I replied. “Erwin me eye,” he flared. ‘“‘No guy that drives like that should be called Erwin. From now on your name is Cannonball, and your pay is eighteen a week.” The name stuck, although I’ve had a couple of raises in pay since then. Well, I worked with that circus all summer, racing around the dirt tracks throughout the Middle West. I managed to save about $150—and you can guess what I Pre st oo sa POPULAR SCIENCE MONTHLY Cannonball at the wheel. The auto, he says, is the safest, most convenient, method of travel man will ever know. bought with my. savings. Right! A brand-new motorcycle, bright red, and guaranteed to deliver eighty miles an_ hour. When I got through tun- ing it up, there wasn't a bike on the dirt-track cir- cuit that could outrun that streak of red paint. My next couple of years were spent in breaking track records at various state fairs. Ive never figured up how many local records I broke, but it’s way up in the hundreds. It was a tough racket, but I gained a helmetful of experience. Some of those experiences were wildly hazardous, involving the loss of limbs, machine, and once or twice the lives of close as- sociates. One day a chap named Bob Perry and I were meeting some local boys in a twenty-five-mile exhibition race at Rockford, Ill. I was out in front, leading my team mate Perry by about fifty yards; the rest of the pack was half a lap behind. A vicious blow-out twisted the handlebars out of my grip, my machine whizzed from under me, and I ‘was catapulted in a semicircle through the air, landing flat on my back in the middle ‘Erwin me eye,’’ flared the Big Boss. **From now on your name is Cannon- ball, and your pay is eighteen a week.”’ 51 of the track. My instinct was to get up and crawl off the track. But a secondary.reaction told me that old Perry would come’ thundering past in a split second, and that the slightest movement on my part would confuse matters fatally. So I lay motionless on my back, look- ing up at the deep blue sky for three eternities. Perry, by adroit steering and lightning headwork, veered his machine away from my head and midriff—but couldn’t avoid my ankles. He shot across my shins going like a motor-driven bullet. As soon as he was past, I rolled over and over till I reached the edge of the track, and sat up in time to see Bob slide across the finish line an easy winner. I made him buy me a quart of liniment 8 with his prize N money —and he said he was glad he T didn’t have to spend \\ BosSce the money on HEL ott flowers. I soon began to notice something about my motor- cycle brethren. They could go just as fast as I could, and were every bit as nervy — but somehow _ they didn’t seem to have my endur- ance. I discov- ered that I could ride for twenty- four hours a day, and feelasfit at the finish as at the send-off. This quality of endurance had no _ particular value in .the twenty-five-mile races, but when the motorcycles began to im- prove, and we were asked by manufac- turers to shoot at long-distance marks, I realized I could sit astride a bike just a bit longer than the other fellow. In 1916 I determined to give my staying powers a thorough test. So I entered in the twenty-four-hour grind at Cincinnati, Ohio, where they were holding out a big stake to anyone who could break the track record for distance. We started off at eight a.m., and for sixteen hours I clicked off better than sixty-five an (Continued on page 164) Cannonball is proudest of his latest feat of crossing the continent in three days, then turning around and recrossing it.

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ee Soames. cao tease ERR A os Ca I 52 Are You in the Right Job? Psychologists Prepare a Series of Questions That Will Help You Get a Line on Yourself By RUTH MOORE MORRISS RE you happy in your job, or do you chafe under the drudgery of your daily tasks? Do you know whether you are doing the kind of work for which you are best fitted? Science has just reduced to a minimum the guesswork in answering these ques- tions. Using a test perfected after years of psychological research, you now can pick the right job for yourself with scientific accuracy! The new occupational guide, which by special arrangement with the men who devised it I present below, is the work of Dr. John J. Morgan, Dr. C. A. Neymann, and K. D. Kohlstedt, of Northwestern University, Evanston, IIl. Humanity, broadly speaking, is divided into two major psychological groups—the extroverts and the introverts. Reducing this distinction to its simplest terms, an extrovert is a mixer, a “go-getter.” An introvert is a dreamer, a creator. HIS test is composed of fifty statements, each being followed by the '[ woras **Yes”’ and “‘No.”’ There is no implication of right or wrong in any of the statements and you are asked to consider them from the viewpoint of personal like or dislike. Read the first statement and if you like the idea that If you dislike it draw a line under No. Proceed in the same way with the rest of the statements. After you have finished turn to page 144 and judge your temperament and ability by com- it expresses draw a line under Yes. POPULAR SCIENCE MONTHLY More specifically, an extrovert is a person who is open to suggestion, free of self-consciousness, friendly toward people and dependent upon them, and whose success depends upon being in a position where he meets people and works with them. For those reasons, most diplomats, orators, and saiesmen are extroverts. Pronounced examples, according to the Northwestern psychologists, are the late Theodore Roosevelt, Mussolini, Alfred E. Smith, and Chief Justice William H. Taft. The introvert, on the other hand, does not depend for his success upon contact with other people. He makes up his own mind and then knows exactly what to do. Hence he makes a good executive or keen analyst, but a poor salesman; a fine research worker or scientist, but a medi- ocre social service agent; an inventor, editor, or composer; but not a promoter, reporter, or orchestra conductor. Out- standing examples of the introvert class are the late President Wilson, Colonel paring your answers with those printed there. APRIL, 1929) Lindbergh, Calvin Coolidge, and Herbert Hoover. The Neymann-Kohlstedt test enables you to size up your own case, to diagnose your own character and personality. You need only answer honestly the series of fifty questions on this page, then judge yourself by comparing your answers with those on page 144. If your answers agree with those printed there, you are a pro. nounced extrovert. But most people are not 100 percent extroverts or introverts, Therefore, if twenty-eight of your answers or more agree with those of the sample, it is sufficient to indicate that your tendencies are extrovertal. If twenty-eight or more are in disagreement, your tendencies are introvertal. Application of the new test to the problem of employment in business and industry will, in the opinion of leading psychologists, result in saving millions of dollars now wasted in people unsuitably employed and in labor turnovers. 1. Be by yourself a great deal. Yes No 27. Think a great deal. ; Yes No 2. Think of life in terms of pleasure. Yes No 28. Be able to express your keenest feelings 8. Always be calm and collected. Yes No (joy, sorrow, anger, etc). Yes No 4. Have a great deal of confidence in others. Yes No 29. Seldom pay attention to details. Yes No 5. Think or dream of what you will do five 30. Be exceedingly careful in meeting people. Yes No- years from now. Yes No 31. Seldom think about yourself. Yes No 6. Stay at home during a social affair. Yes No 32. Puzzles. Yes No 7. Work with many people around you. Yes No 33: Act on suggestions quickly rather than stop- 8. Do the same kind of work all the time. Yes No ping to think. Yes No 9. Enjoy social gatherings just to be with people. Yes No 34. Read about rather than do a thing. Yes No 10. Think a great deal before deciding anything. Yes No 35. Enjoy the story more than the way itiswritten. Yes No 11. Accept suggestions rather than working them 36. Keep a personal diary. Yes No out for yourself. Yes No 37. Keep quiet when out in company. Yes No 12. Quiet rather than exciting amusements. Yes No $8. Act on the spur of the moment. Yes N 13. Dislike having people watch you. Yes No 39. Have notiiing to do with people holding 14. Quit a tiresome task. Yes No views opposed to your own. Yes No 15. Save money rather than spend it. Yes No 40. Dislike thinking about yourself. Yes No 16. Seldom analyze your thoughts or motives. Yes No 41. Seldom change an opinion already formed. Yes No 17. Indulge in reverie (daydream) or thought. Yes No 42. Change from one type of work to another 18. Have people watch you do things that you frequently. Yes No do very well. Yes No 43. Avoid trouble rather than face it. Yes No 19. Let yourself go when angry. Yes No 44, Believe that rumors are important. Yes No 20. Work better when people praise you. Yes No 45. Confide in others. Yes No 21. Have excitement. Yes No 46. Distrust people you have just met until you 22. Be a leader at a social affair. Yes No get better acqutsinted. Yes No 23. Speak in public. Yes No 47. Study others rather than self. Yes No 24. Dothethingsthat you dream about (daydream). Yes No 48. Spend your vacation at some quiet place 25. Rewrite social letters. Yes No rather than at a lively resort. Yes No 26. Get things done very quickly rather than 49. Seldom plan out work before you begin it. Yes No being slow but sure in movement. Yes No 50. Take part in conversations going on near you. Yes No © C. A. Neymann and K. D. Kohlstedt wn Nee oe et So” ED ~~ menane 2 2 Seams et

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POPULAR SCIENCE MONTHLY 53 a a va Herbert enables Ly. . You eTies of N judge ers with TS agree Memorial service aboard the U.S. ice patrol cutter Modoc over the spot where > & pro- the Titanic collided with an iceberg and sank with 1,503 souls in 1912. »ple are roverts, your S | - of the - aying the Ice Monsters al. If ement, to the ‘ A ~ Frozen Giants Blasted to Bits—How U.S. Patrol Boats ° ° e 99 e . nae Trail Atlantic “Growlers” and Guard Ships from Peril By MICHEL MOK ” OUR bergs in sight in a radius of souls on her maiden voyage in 1912. that it has virtually been abandoned. seven miles. Fog getting dense. Time was when the cutters attacked But while the Modoc and the Tampa Danger to westbound traffic. Sixty the bergs with TNT, other high ex- were making ready for this year’s cruise, growlers northeast Cape Race.”’ plosives, and even gunfire. But this Dr. Howard T. Barnes, noted engineer of Here is a message typical of the radio method proved so ineffec- McGill University, flashes that are now being received daily tual in the fight against Montreal, Canada, was by the U. S. Hydrographic Office at Wash- the mountains of ice engaged in actual bat- ington, D. C., from the Interna- tle with ice jams in the tional Ice ag They tell the pouting bss me small ice- St. Lawrence River. No thrilling story of a bloodless war a Se ene See eee Accompanied by a that is being waged by our Coast = wy = —s = small sees of assist- No Guard upon one of the brute, de- ants, Professor Barnes No structive forces of Nature. burned hundreds of No The annual ice crusade is on! thousands of tons of No Two sturdy little cutters of the ice out of the stream No U.S. Coast Guard, the Tampa and by the thermit process, the Modoc, constituting the patrol, perfected by him after No left their base at Halifax a few years of experiment. No weeks ago. Straight north they This method makes No steamed into the home of the white use of the intense heat No monsters that threaten vessels. It produced by firing a No is their perilous task to track the mixture of fine alumi- No icebergs which, each spring, break Courtesy num filings and iron from the Greenland ice cap and Prof. H.T. Barnes _ oxide. No swing down into the steamship With the judicious No lanes, and to make them harmless use of thermit, Dr. Barnes claims, icebergs No to vessels that ply the North may be destroyed before they become a Atlantic. menace to Atlantic shipping. A couple of No The Tampa and the Modoc keep years ago, off the Newfoundland coast, he No day-and-night vigil until June, blew three icebergs to fragments. Now No when the danger to shipping will be the Canadian government has invited him No past. For the cutters it is a period to clear the St. Lawrence and obviate a of unbroken action—dogging the repetition of the disastrous floods of last No trail of the mobile marble towers spring, when ice from Lakes St. Louis and No until they melt, and sending ship- St. Francis drifted down and piled up in a masters of many nationalities warn- jam in the river below Montreal. No ings that enable them to steer clear Not in itself an explosive, thermit, No : the giant peaks, and so avoid — set off ge a time fuse, quickly No isastrous collisions such as that ; ti ’ develops terrific heat, reaching a maxi- tedt which sank the Titanic with 1,503 perernneny mag «yeaa b omameniar hand 4 mum of 6,000 (Continued on page 142)

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Roan en — eS ” . ) ‘ Sea | ee POPULAR SCIENCE MONTHLY Wing Strength Tested by Piles of Sandbags OOPING-THE-LOOP and topsy- turvy flying cause strains that are mild compared with those to which wings are subjected in an airplane factory at Burbank, California. Before new wings are attached to the streamline fuselage of this make of machine, they are loaded with several hundred sandbags while testing engineers watch their strain-recording instruments. After the sandbags are removed, the wings are gone over carefully to see if the stringent test has revealed any weak- nesses. Planes of this type were used last year by Art Goebel on his record-breaking Lindbergh’s Trophies Fill Wing of Memorial ‘Ste ae filling the entire west wing of the Jefferson Memorial in St. Louis, Mo., prove the world’s esteem for Col. Charles A. Lindbergh. During his tours of Europe and Latin America after his spectacular crossing of the Atlantic Ocean in May, 1927, medals and plaques, pictures and loving cups were showered upon him. One of the latest additions to the collection is the Harmon Trophy, pre- sented by the International League of Aviators during the International Civil Aeronautical Conference at Washington, D. C., which marked the twenty-fifth anniversary of man’s conquest of the air. cross-continent flight, and by Wilkins and Eielson on their trip over the top of the world from Alaska to Spitsbergen, and also for a series of flights in the ’Ant- arctic regions which these explorers have made more recently. How Starlight Is Measured by Photo-Electric Cell HE light of stars is measured by photo- electric cells. Dr. Joel Stebbins, of Washburn Observatory, Madison, Wis., recently explained that a photo-electric cell is an electric lamp which works backward; in an ordinary bulb you put in current and take out light, while in the photo-electric cell you put in light and get a cur- rent dependent in intensity upon the strength of the light. A star image is focused upon a delicate photo-electric cell by the telescope and the resulting current measured by a gal- vanometer. Planes Glide into River Like Ducks FREIGHT car float, several hundred feet long and sixty feet wide, has been turned into a unique runway for amphibian planes by the Loening Aero- nautical Engineering Co., of New York City. APRIL, 1929 eo se One end of the float is attached to the bank of the East River. The other, by means of bulkheads filled with water, js lowered several feet below the surface of the water. The machines land upon the river, taxi to the float, lower their wheels, and run up on dry land to discharge o take on passengers and cargo. When they are ready to leave, the planes roll down the runway into the water as ducks wade into a pond before swimming away. The runway eliminates the inconveni- ence and danger of transferring passengers between the plane and a launch or row. boat when starting or ending a flight. The rise and fall of the tide does not interfere with the operation of the device, because it is attached at only one end. One of the first to use the new runway was Col. Charles A. Lindbergh. Similar runways for amphibian planes are ex- pected to be established as part of the airport equipment of municipally-owned fields bordering on rivers or other large bodies of water. Tests Breath of Honeybees Y ANALYZING the breath of the honeybee, Prof. G. H. Vansell, of the University of California, discovered that in winter, when the hive is at rest, the bees absorb moisture from the air, while in summer, when they are working, they give off twenty-five times as much moisture in breathing. He suggested that this gave a possible index to the health of the hive, thus bringing scientifie research to the aid of the beekeeper in the fight against destructive diseases. A flying boat sliding into the water from launching way devised from a freight car float. The run- way is used also in discharging passengers and cargo. St forv “ tr Lig “le a le the thi kn gi

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ed to the other, by Water, jg urface of upon the r wheels, har ‘ge or hen they oll down ks wade Ly. Convenj- ssengerg or row. ht. The nterfere because runway Similar ure ex. of the -owned r large ees of the of the 1 that t, the while _ they much ested > the ntifie er in S. ing in- ZO. POPULAR SCIENCE MONTHLY Sturdy Monoplane Wears Streamlined “Pants” is the latest development in stream- lined aircraft. Both wheels of the forward landing gear, and the struts sup- rting them, are incased in streamlined “trouser legs” to reduce head resistance. Lights are provided at the top of each “leg” to aid in maneuvering the plane to a landing at night. The cabin, motor mounting, and even the exhaust pipes are designed to slip through the air with the least possible resistance. As a result, the monoplane, known as the “Scout,” is said to have given a remarkable performance at its \" AIRPLANE that wears “pants” Tractor Tows Out Giant 12-Passenger Plane _ a tiny ant dragging a large but- terfly along the ground is the small tractor which hauls a new big air liner to the starting point at the Oakland Munic- ipal Airport, Oakland, Calif. This new twelve-passenger biplane recently took off on its first flight on a regular Oakland- Chicago air service. It follows an almost direct line east and west on its runs to and from Chicago. The new plane, one of the largest ever put into passenger service in America, is driven by three powerful motors, and is equipped with steel propellers. The un- usual width of the landing gear can be noted by comparing it with the size of the man and tractor in front of the plane. initial trial in Los Angeles recently. It whizzed through the air at 200 miles an hour at an altitude of 1,000 feet, yet landed at only one fifth that speed, drift- ing down to the airport at the compara- tively slow speed of forty miles an hour. It also is asserted that the plane cannot go into a tail spin. The wings, with a spread of thirty-five feet, are internally braced and placed low. They are made of plywood. As a proof of their strength, the designer allowed nineteen adults and two children to stand in a line on top of them as pictured above. Under this weight the wings remained rigid. The designer of the plane is M. C. Tunison, formerly an aeronautical engi- neer for the Government. Test ‘Cast Stone”’ Strength With Tiny Cylinders N LITTLE cylinders, two inches long and two inches in diameter, “cast stone,” the new building material re- cently described in Poputar SciENCE MonTHty, is being tested at the Bureau of Standards, Washington, D. C. Its average compressive strength was dis- covered to be 6,250 pounds a square inch. Other tests of the unique artificial ““stone’’ will be conducted shortly to de- termine its freezing resistance and water absorption characteristics, so builders may have definite knowledge of how the material will act under given conditions. a cas a Tractor towing the giant Boeing air liner, which carries twelve passengers on Oakland-Chicago trips. The great size of the “Pullman of the Sky” is apparent when compared with che tractor in front of it. Pi Siar ¥, ess } aE BABS i ish y XS | Fey BURL s Sh A fy R-100 Passengers to Land on 270-Foot Mast WO hundred and seventy feet above ground, passengers on the British dirigible R-100 will step from the airship to the landing platform of a mooring mast recently completed at Montreal, Canada, to serve as a terminus for the sky liner on its maiden voyage from Eng- land this year. The huge rigid gas bag, as large as the steamship Mauretania, is to be moored by its nose to the top of the mast so it can swing about with changes in the direction of the wind. A gangplank, pushed out from the cabin passageway, will transfer pas- sengers to the tower’s platform. Eleva- tors will facilitate the unloading and loading of passengers and baggage when the sky liner arrives and departs. The new arrangement is expected to simplify the “docking ”’ of the airship. When the Graf Zeppelin arrived at Lakehurst, N. J., last fall, much time was consumed in bringing the airship to rest near the ground, so the passengers could descend on short ladders, and in attach- ing it to the stub mast used to moor it. Designers of the Montreal mast believe their design has solved many of the land- ing problems of rigid airships.

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- Fa a TT SS in TERE Gas SE eae tees 56 Tiny Propeller on Man’s Back Pushes Him Uphill IHE latest invention of the Brazilian aviation pioneer, Alberto Santos- Dumont, is a tiny air-cooled motor and propeller which, strapped to a man’s back, pushes him uphill on skis, thus saving his energy while engaging in the sport. The single-cylinder motor, com- plete with gasoline tank, propeller, and framework, weighs but three pounds. The inventor has named the device an “ornithonico.” Aided by Rio de Janeiro’s mayor, he recently demonstrated it before crowds which thronged that Brazilian city at a celebration in his honor when he returned from France. Santos-Dumont, the man wearing a dark suit and standing in the center in the photograph, was a pioneer in aviation. In 1906, he made a hop of several hundred feet near Paris, France, in a biplane modeled after a box kite. His earliest air fame came from exploits with dirigible balloons, which he began constructing in France in 1898. He won international recognition by capturing the Deutsch Prize of $50,000, in 1901, by flying from St. Cloud to the Eiffel Tower and return in one of his gas bags in less than half an hour. While Santos- Dumont was born in Brazil, he has lived for long periods in France, where all of his flying ex- periments were conducted. Motor Boat Leaps Through a Hoop ASHING over the water at J thirty-five miles an hour, a tiny hydroplane, the Oh Kay, its outboard motor racing at full speed, shot up a greased slide, tore through a paper hoop, and leaped forty feet when it recently inaugurated a nerve-tingling sport on Lake Elsinore, Calif. The pilot, Floyd Pierce, estimated the craft was eight feet above water at the height of its jump. The boat used in the gruelling test was one of the victorious entrants in the out- board division of the Detroit Regatta last fall. A jumping contest was added to the program of the midwinter races on Lake Elsinore after the Oh Kay had shown it could withstand the strain of the thrilling exhibition. Great skill is required to maintain the balance of the little boats during the leap so they will strike the water on an even keel. This was made more difficult in Pierce’s first jump because a piece of paper from the hoop caught on his head, as can be noted in the pic- ture. In spite of the fact that he was momentarily blinded, he landed safely. New Dredge Driven by Diesel Motors ponte off the ways at ») Manitowoc, Wis., the first of a series of unique dip- per dredges, designed for Great Lakes service, struck the water of Lake Michigan New steel dipper dredge sliding off ways at Manitowoc, W: Michigan. Diesel engines operate machinery on board this unique craft. POPULAR SCIENCE MONTHLY Floyd Pierce jumps motor boat through hoop. recently and was started on the journey to the scene of its first operations. The new type dredge is of all-steel con- struction and the dipping machinery is operated by electricity generated on board. Powerful Diesel motors, using heavy oil, cheaper than gasoline, operate generators which furnish the current. is., into Lake APRIL, 1939 Finds Some Germs Prefe; Blonds for Victims ERMS also prefer blonds. (; ing a victim, the chainliie't Choos streptococci, which infect man With var ous diseases, pick a person with a leh skin rather than one with dark, according to Dr. Samuel J. Holmes, of the De ment of Zoology, University of Cali. fornia. The germs make their entrance ty the body through the outer skin. Studies of mortality tables show that the diseases caused by such germs are less frequent among negroes than q whites, Dr. Holmes reports. He believes that the pigment in dark skin is not a pro. tection, except against light rays, byt that the production of pigment possibly is an index to a vital resistance to the sort of infection produced by the streptococ¢i, Pinpoint Device Registers Heat from Far Suns N INSTRUMENT so small it would take a thousand to equal the size of g drop of water was used recently by Dr, Edison Pettit and Dr. Seth Nichol. son, at Mt. Wilson Observatory, to measure the heat of stars billions of miles away :This device was cop. structed under a microscope. It is a thermocouple and will register variations in heat as slight as one hundred thousandths of a degree. Used in connection with the 100-inch Hooker telescope at the Mt. Wilson Observatory, the sensitive instrument recorded the heat coming from 124 stars. Betel- geuse, a flaming sun 27,000,000 times as big as our sun, raised the temperature of the receiving in- strument only one sixtieth of a degree centigrade, so far away is it. The heat radiations measured by the thermocouple showed certain stars to be larger than indicated by the Michelson inferometer, previously used for such measurements. Use Poison Gas to Rout Foes of Pineapples POISON gas offensive is being waged by pineapple growers in the Ha- waiian Islands against the nematode, a worm pest that attacks the roots of both pineapples and sugar cane, destroying from fifty to ninety percent of the crop. Multiplying rapidly, the plant enemies have increased tremendously in recent years. The planters tried to halt the inroads of nematodes with potassium cyanide, car- bon bisulphate, and chlorine, but none of these poisons proved effecfive. After two years of research, chemists of the U. S. Army stationed in the islands suggested the powerful toxic gas, chloro- picrin, as a means of fighting the worms. Tests have been conducted with remarkable success. The deadly gas not only exterminates the pests, but appears to stimulate the growth of the plants as well.

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PRIL, 1999 Prefer ns In Choos. + bacter; with var. ha light accord; B Depart. of Cali. itrance to L. how that iS are lesg l among > believes 10t a pro. ays, but Possibly » the sort Ptococei, Sters nas it would ‘size of g ’ by Dr. . Nichol. itory, to illions of vas con. ye. ind will aS slight hs of a on with cope at ry, the ded the Betel- 000,000 ised the ing in- h of a ay is it, by the ‘ars to chelson r such ut waged ie Ha- ode, a of both Toying e Crop. y, the Teased years. o halt atodes e, car- lorine, isons r two ists of 1ed in 1 the hloro- shting > been ‘kable only , but the well. APRIL, 1929 Gilded Auto of 1903 Still Runs in Fine Style WENTY-FIVE years old and - | still going none? = hat is 9 of an early steam auto- reo in Los Angeles, Calif., which still is able to bowl along the streets of that city at a good speed. The original owner of the machine is not known, although he is believed to have been the resident of a western railway. A quarter of a century ago, the machine represented the acme of the horseless carriage craft. In- Jaid rosewood, trimmed with ma- hogany, decorates the interior and the seats are covered with the finest plush. The fixtures inside are silver plated. A speaking tube con- nects with the driver’s seat and, for the convenience of passengers, a small writing desk can be unfolded from the wall. For lighting the car’s path in 1903, both oil and carbide lamps were employed. Despite the vehicle’s age, its owner claims it will still be running when many cars of today are on the junk pile. Builds Sailing Yacht of Turkey Bones THANKSGIVING turkey furnished the keel for an un- usual model yacht built by Harry Bock, a workshop enthusiast of Manchester. Center, Vt. Upon the polished breast bone, the deck and masts were fastened. Smaller bones from the breast were used as spars to tauten the rigging of the miniature sails. With ballast added, the unique toy vessel is said to be able to sail across a pond as successfully as any conventional model yacht. Its main interest, however, is as a curiosity and an unusual product of the workshop. These **Cukes’’ Cannot Fail NEW hybrid variety of cucumber whose flowers do not have to be pollinated was described recently by Prof. Richard Wellington and Leslie K. Hawthorn, of the New York State Agri- cultural Experiment Station. The cer- tainty of a crop is assured by this new species, they declared. Plans to Use Tung Nuts for Making Paint Oil IL from Chinese tung nuts, which long has deen used in paints and varnishes, will be produced on a large scale by T. Morris Carnegie, nephew of the late Andrew Carnegie, famous steel maker and philanthropist, if experiments being carried out on his estate near Fernandina, Fla., prove successful. Mr. Carnegie estimates that mature tung trees will produce from 400 to 1,800 pounds of vegetable oil to the acre, quan- tities which, he believes, would make the production of his nut oil commercially profitable, just as oils from olives, pea- nuts, cottonseed, and other plants of the vegetable kingdom are now sold in large quantities. Tung trees are already producing large POPULAR SCIENCE MONTHLY Steam auto of 1903, still running, has silver plated fixtures, plush seats, and interior trim of rosewood and mahogany, With its keel of a turkey’s breast bone, this unique model yacht sails like a full-sized craft. quantities of nuts on the Carnegie estate. In China, these are crushed to make oil for paints and varnishes. In the East Indies an allied tree of the Chinese tung yields a wood oil known as gurjun bal- sam. Both these products, though little known in this country, have been in general use in the Orient for many years. T. Morris Carnegie (at left) inspects oily nuts from Chinese tung trees on his Florida estate. 57 Can You Give a Name to Ultra-Violet Ray? CIENCE needs another word to designate what we now call ultra-violet light. “Ultra- violet” simply means “beyond the violet” band of the solar - spectrum, which indicates that the rays are invisible and so are not light at all in the ordinary sense of the word. Anyway, the discovery‘ that these ultra-violet rays are neces- sary to life and are responsible for the vitamins in our food is being put to a thousand practical uses. An English farmer, V. M. Weall, of Surrey, experimented with pigs, exposing the porkers daily to ‘ultra-rays from a quartz lamp for lengthening periods for ten weeks. Twelve pigs were untreated, as controls. When the little pigs went to market the ones which had re- ceived the ultra-ray treatment were so much fatter and better that they brought far higher prices than the others, enough to repay the cost of the treatment fourteen times over. Sign of the Pawnbroker Urged as Air Marker W shapes and colors of glass are being sought for airway markers. How to mark radio antenna poles is a_ particular problem. Lights at the top are likely to cause interference. Flood- lights at the bottom do not reveal the tips with sufficient clearness. One suggestion 1s to place the familiar pawnbroker’s sign of three balls at the top and illu- minate it with a spotlight placed below. Electrified Water Keeps Fish Out of Ditches MAZING screens formed by stream- ing particles of electrified water are being used in the Northwest to keep young trout and salmon out of irrigation ditches. When schools of these fish stray into the ditches, loss results to the fishing industry, so experts of the Federal Bureau of Fisheries have been investigating to find the best method of turning them back at the mouth of a ditch. They discovered that fish are sensitive to electric shocks and dread to pass through electrified water. So “electrical screens” were suggested and tried, using several schemes to electrify the water. The same idea was adopted by the engineer of a power company on the Pacific Coast to keep fish out of the turbine wheels of a hydroelectric plant. On wooden frames over the water he suspended two rows of parallel electrodes which set up an electric field reaching to the bottom of the stream. The strength of the field tapered off in direct propor- tion to the distance up or down stream. Thus each fish approaching the turbine wheels entered the electrified area and received a shock. If it did not turn back at the first shock, but swam nearer, the severity of the shocks increased rapidly as it approached the whirling wheels.

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ee ee ae apd: a neces, Sar eee, 4 S| Boys Build ‘“‘Human Engine”’ in Study of Anatomy SING two furnaces for the stomach, twin bellows for the lungs, a little pumping engine for the heart, and other mechanical devices for various POPULAR SCIENCE MONTHLY Federation Aeronautique Internationale, the world-governing body of aviatiou, has recognized as official the Graf Zeppelin’s eastward distance record. The entry: “Class B (Dirigibles): distance (Ger- many), Dr. Eckener, with the dirigible Z-L. 127, ‘Graf Zeppelin’; motors May- bach 450-550 HP, from Lakehurst, U. S. A., to Friedrichshafen, Germany, Octo- ber 29-30-31, Nov. 1, 1928, 6,384.5 kilo- meters.” This is equivalent to 3,967 miles. The last previous record in this class was set by two Italians who made a 503-mile dirigible flight in 1913. First American Cat Had Teeth Like Daggers 4 LL modern cats, from tabbies to Angoras, are believed by Paul C. Miller, associate curator of paleontology at the University of Chicago, to have de- scended frem a prehistoric feline whose bones he found recently in Nebraska. For thirteen summers he searched for the big cat of antiquity he believed had roamed over the western plains 10,000,000 years ago. His search ended in the basin of Hat Creek, Sioux County, where he APRIL, 199) paul, Hoard in England Adds to Bronze Age Mystery HE so-called Bronze Age is believed to have been the tage la human culture intermediate between Stone and Iron Ages, and to have approximately from 2,000 B.c. until } B.c. Many archeologists of note, how doubt that there ever was a distj bronze era, but contend that the ages more or less overlapped, basing belief on the fact that bronze imp} have been found in ancient burial side by side with iron and, sometj even stone ones. Fresh impetus was injected into question when workmen, digging flint with which to build a road jn hills of Surrey, England, came upon gy unusually complete and _well-preseryad collection of bronze tools and weapons Many of the fine pieces were sent tog museum, where experts voiced the th that the find was the buried hoard of ay ancient caster who had placed his stock. in-trade in the ground for safe-keeping and then, evidently overtaken by som tragedy, had been unable to dig it w again. organs of the body, British schoolboys, studying anatomy, constructed a mechanical man to illustrate the functions of these organs by machinery. Their “human engine” sim- plifies the processes of the hu- man body by giving a working demonstration of each organ. When the furnaces generate steam, the pumping engine drives up and down the pis- tons which operate the bellows of the lungs. Then the me- chanical man wheezes and throbs as though panting. A head, arms, and legs are fitted to the case inclosing the me- chanical organs to add realism. Python Takes Whole} ™" Deer at One Gulp J“ WHOLE deer disappearej § sent down the throat of a huge mon python in the Malay States r. TI cently, according to the report mon of hunters who watched the a pe record-breaking meal and then whe! killed the serpent as it lay ina was the animal. Before this report was made public, goats wer believed to be the largest ani- mals which pythons could swallow. These huge snakes, able to crawl, climb, and swim with equal facility, weigh hundreds Nitrates from Africa TRATES essential in pro- ducing explosives in war time and valuable as a fertilizer in peace have been discovered in Southwest Africa, it is reported. Practically the whole sup- ply in the past has come from the famous nitrate mines of Chile, in South America. The African product is said to be superior to the Chilean deposits. Paul C. Miller, of the University of Chicago, with the skeleton of prehistoric cat, found in Nebraska, for which he searched 13 years. Graf Zeppelin to Explore Arctic Near Alaska N APRIL, 1930, the great German dirigible Graf Zeppelin will point its nose toward the Arctic, according to Dr. Fridtjof Nansen, famous Scandinavian explorer, who will command the expedi- tion. The airship will be used by the Aero- Arctic Society in exploring unmapped territory northeast of Alaska. Dirigibles now occupy an increasingly prominent place in aeronautical news. Construction is under way at Akron, Ohio, of the plant that is to build the Navy’s two 6,000,000-cubic-foot dirigi- bles. It will include one of the world’s largest hangars—a building a quarter of a mile long. From France comes word that the discovered an almost perfect skeleton of the extinct animal. Measuring nearly four feet in length, it possessed powerful dagger-sized teeth to tear its prey. Three Chemicals of Life Flow in Our Blood HE three chemicals which play lead- ing réles in keeping -us alive, blood specialists have decided, are hemoglobin, chlorophyll, and a phosphorus compound, still virtually unknown. This trio gives the blood stream its power. Hemoglobin, the red blood chemical, supplies iron to the vital current. Green chlorophyll, which tints plants, absorbs excess carbon dioxide gas from the air. The mysterious phosphorus compound forms the central nuclei of living cells. It has been suggested that this pkcsphorus chemical is the one with which all animal life seems to have begun. of pounds and often attain a length of thirty feet, causing them to be greatly feared throughout the tropical parts of Africa, Asia, and Australia which they inhabit. After a victim has been killed by squeezing it to death, the serpent crushes the bones and mangles the body into the shape of a sausage so that it can be swal- lowed whole. Another peculiarity of the pythons is the manner in which the female hatches her eggs. Depositing as many as a hundred in a heap, she curls around them and remains in the same position without food during the period of incuba tion, which often lasts two months_ Itis thought this is not to keep the eggs warm, but to protect them from harm, The python just after it had made a record by swallowing a deer. These snakes, often thirty feet long, weigh hundreds of pounds. sluggish state while digesting char

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lany as around osition ncuba- | Itis e eggs harm. , a od AprIL, 1929 POPULAR SCIENCE MONTHLY 59 Comparison with the men in the photo shows the tremendous bulk of the marble monolith. the sea in the Italian Alps, workmen in the famous Carrara quarries drilled and cut for five years to carve from a mountain what is believed to be the world’s largest monolith of marble. This white stone block, nearly ten feet square and sixty feet long, has been pre- sented to Mussolini for erection as a monument in Rome. The problem of transporting the heavy monolith—weighing 250 tons, as much as a powerful freight engine—to the sea, where it was loaded on a ship for Rome, was solved in a peculiar way. Those in charge, instead of consulting engineers, searched into history. A similar monolith of stone was known to have been brought to Italy from Egypt in the days of the old Romans. By scanning ancient rec- ords the method that had been used then was discovered and it was applied in lowering the Carrara block. The shaft was incased in a fifty-ton covering of wood to protect it on (oye thousand feet above Five Years’ Work to Quarry One Block of Marble Stout steel cables slowly lowering the marble block along a specially constructed roadway. mable gas ignited and, in an instant, tongues of vivid flame were shooting sixty feet into the air—higher than some near-by buildings. For whole blocks the pavement seethed with billows of fire. Quick work by London “Bobbies” saved the day. An emergency call sent in cut off the gas supply before the fire had caused disastrous destruction. ‘ yy Lar 3 ? Incased in heavy wooden jacket, the gi- gantic shaft is prepared for trip to Rome. Old Letter May Tell Secret of ‘‘Strad”’ F A yellow sheet of crumbly paper found recently in the secret drawer of an old desk at Bergano, Italy, turns out to be what musicians hope it is, every aspiring young violinist soon will play upon a coveted “Strad.” An antiquarian, examining the piece of furniture, accidentally came upon a letter written by Antonio Stradivari, the master violin maker of Cremona, to a priest, setting forth in detail the methods of wood-treating and varnishing he used more than 200 years ago in the production of his matchless instruments. These secrets were supposed to have died with Stradivari and authentic violins signed by him, possessing un- rivaled beauty of tone, are extremely valuable and eagerly sought for as the journey. In fastening and bolt- ing in place the several layers of boards and timbers that clothed the monolith more than 10,000 nails and bolts were used. Special steel cables of 160 strands each, made in Vienna, Austria, en- circled the case and increased its strength. Cables of the same material also were used to steady the block. They were played out a little at a time as it slid down to the shore along a special roadway which, it is said, required more than a year to construct. With the web of taut steel cables sieadying it, and guided by an army of laborers, the monolith descended by easy stages to the waiting vessel. Gas Blows Up Mile of London Streets MILE of London streets ex- ploded recently. With a series of roars like four huge bombs being set off, one after the other, an underground gas main burst in the west central section of the British a result. At first, it is reported, it was the finder’s plan to sell the letter to a violin maker in Milan, but when this was discovered by the author- ities they prevented him from car- rying it out. At present, the manuscript is in the hands of the Italian government. Would Banish Cupid for Rule of Eugenics LEAVE all matters con- cerning future generations to Nature is an error, in the belief of Ralph E. Danforth, of Chester- field, Mass., an authority on eugen- ics, who holds the aim of eugenics is to improve the human race and make its individuals worthy of being loved. “Increasingly more intelligence is required in our choice of lovers. The use of at least the same amount of intelligence and forethought in courting as in the less important branches of activity, such as dress- ing and eating, is demanded by capital. The rushing clouds of inflam- Sixty-foot flames shooting five stories high when gas from a broken main explodes along a mile of London’s streets. common sense and by love alike,” Danforth recently declared.

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60 POPULAR SCIENCE MONTHLY J ieeea ~ Set on ta he Yen) ° i Pate BuPas a? fish from Key West waters are believed to have brought the death- dealing malady with them. The only tropical denizens known to be immune to the disease are sharks, morays, skates, and eels. Other fish from semitropical waters first became blind and then died within five or six days after being infected. The disease was. checked by pumping out 100,000 gallons of water used in the Aquarium’s tanks and replacing it with water from New York Bay. Sound Films to **Talk’’ in Testing Studio THREE-STORY laboratory, to be devoted wholly to the study of problems in connection with talking movies, is being constructed by the Bell Telephone Laboratories in New York City. Facilities for the complete production of sound films for experimental purposes will form part of the equipment. The top floor of the building will be occupied by a large studio where Electric ‘‘Bos’n’”’ Shouts Orders on Warship TH ninety “tongues” singing out orders at the same time, an “electric boatswain’s mate,” re- cently installed on large British warships, spreads the command over all parts of a vessel within a few seconds. Directions for the crew are spoken into a microphone and transmitted through the ninety loudspeakers placed at different positions on the ship. A single movement is all that is necessary to put the com- plicated mechanism in operation. When the door of the case containing the microphone is opened, preparatcry to giving an order, that action automatically sets the system in operation and the words spoken are shouted out of the loud- speakers within five seconds. Quake Takes a Short Cut Through Earth’s Center RAVELING from the Malay Pen- insula to Massachusetts, vibrations of a recent earthquake passed through the center of the globe, according to seismo- graphic records at Harvard University. Verification of the phenomenon comes from similar records at Georgetown University, Washington, D. C. Had the vibrations followed their usual course and circled the globe at its surface, explained L. D. Leet, chief observer at Harvard, they would have been weak when they reached Cambridge. Because the vibrations registered on the American instruments with great ,intensity, it is concluded they must have passed through the center of the earth. Angel Fish Bring Deadly Bacillus to Aquarium STRANGE marine bacillus which causes blindness and death to fish recently killed more than 400 specimens at the Aquarium, in New York City, before the epidemic could be stamped out. Angel the programs will be heard under acoustic conditions similar to those of a theater. A plant of the latest design for handling and developing talking films will be on the ground floor. The films and recordings produced in the laboratory will not be used commercially, it is ex- plained, but will be set aside for experi- ments leading to the expected improve- ment of sound film production. Ready-Lighted Cigarettes Pop from This Holder RESS down the lever of a new cig- arette box and out comes a cigarette already lighted! The movement of the lever releases a single cigarette, allowing ——_ Amn ie APRIL, 1999 ——= | How Much Do You Know About Physies ? oe are ten questions se. lected from hundreds asked by our readers. See how man you can answer. Correct an- swers are on page 143. | 1. What is the difference be. | tween chemistry and physics? 2. What is a vacuum? - How does a thermometer tell temperature? 4. What is the difference he- tween a steam engine and | a gasoline engine? | 5. What is the difference be- tween a wave in water and a sound wave in the air? 6. If water won’t run uphill, | why does a siphon work? 7. Is there any transparent metal? 8. What becomes of the power used to drive an auto- mobile when you take a ride and return to the | starting point? | 9. How does light register a | picture on a photographic _| plate? - What is ‘‘cold light?”’ ow —$___—_! Deliveries Locked Up by Kitchen-Wall Receiver O SAVE steps and protect packages left when no one is home are the purposes of a device designed to be in- stalled in the kitchen wall. It is a com- partment with two doors, one outside the house, the other within the kitchen. When groceries, bottles of milk, or parcels are deposited in the receiver, closing of the outside door locks it auto- matically, the maker explains, thus pro- tecting the articles from theft. When the inner door is opened, the catch on the outer door is released, thereby unlocking it for further deliveries. The size of the receiver is sufficient, if installed in a frame house with a six-inch wall, to accommodate six quarts of milk or articles occupying a similar space. Ready for smoking, a lighted cig- arette pops out when you press lever of this automatic humidor. it to drop upon holders, and at the same time ignites a lighter, similar in action to an ordinary pocket lighter. When the cigarette is re- moved, it is ready to smoke. Releasing the lever auto- matically extinguishes the lighter. The novel humidor has a capacity of forty to fifty cigarettes. Your daily milk supply is protected from theft when auto- matically locked in this parcel receiver in the kitchen wall. Oliver, mecha lisions Usir crosset theory rolling the ra collidi Wh at the weigh’ rear ¢ down, the in a suc weigh trains

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RL, 19% pant, 1929 POPULAR SCIENCE MONTHLY 61 —— - a Finds Germs Existed Before Dinosaurs r r ow Know Your Ca ERMS have outlived the dino- function of a car’s cool- saurs. While the huge monsters ing system is the transfer of of the past have vanished from the we excess motor heat to air flowing animal world, microscopic bacteria ced through the radiator. Assuming have continued to live with but ~ that the cooling system keeps slight changes for millions of years, ” the motor at proper running Prof. T. Brailsford Robertson, of the temperature in the hottest |{ Wistar Institute, Philadelphia, re- e~ weather, it is neither necessary |} cently reported. nd nor desirable to put anything in | A study of bacteria discovered in the radiator except pure water. || thesoil of Australia showed that they ae | This does not apply, of course, resembled the bacteria found in soils | to antifreeze liquids, to prevent in other parts of the world. Because e- | the water from freezing in cold of the striking difference between the nd | weather. larger animals of Australia and those If, after several years of use, on other continents, naturalists be- e~ | vou find your motor has a ten- lieve that Australia has been sep- a dency to heat, it is because the arated from other land masses for 1 cooling system is clogged with millions of years, so that the life there is rust flakes from the iron cylinder has had an independent evolution. at jackets, or perhaps from water The fact that the germs in the soil deposits. The only way to have not become different from those er | | restore the radiator’s efficiency is on other continents leads Professor ; | to flush : i . a hoody a _— —_ Automatic Device Sends rong solution of boiling ho ave remaine e same during all tha oe = This treatment we | not time and are the oldest things living on OutSOS Calls 43 be necessary until your car is at earth. i. a knowledge of radio or io a least two or three years old and - code signal, anyone now can send then only when the water is Lock-It-Open Latch Foils -— distress signals bey Ns ship - air- rticularly hard. ° plane, it is announced. e signal gives | pa Winds and Robbers the position of the craft and its call — O PREVENT a window from rattling letters in the international radio code, and to hold it securely so * cannot all ——— so y are device ) ° H be raised further from the outside when was invent y Lieut. C. A. Perez, of 7 Devises btn an er ig opened a few inches for ventilation, an the Cuban Signal Corps, and it recently r Trains from Crashing ingenious window lock has been invented was tested before U. S. Navy officials. kages OMETHING new in the way of safe- by Joseph Neiser, of London, Ohio. All that is necessary to operate the > the ‘ ty appliances. to reduce railway His latch consists of a right angle rod _ transmitting device, it 1s explained, is to € in- accidents has been devised by G. S. which fastens into a slot in the side of the plug in the correct latitude and longitude con- Oliver, an Englishman, in the form of a upper sash. The lower end of the rod is indications, then throw a switch. Com- le the mechanical device to prevent train col- threaded and carries two lock nuts which _ plete, the instrument weighs only fifteen lisions at crossings. can be screwed tight around a projection pounds and is about the size of a portable k, or Using two toy engines on tracks that on a standard fastened to the top of the typewriter. Because of its compactness eiver, crossed, Oliver recently demonstrated his lower sash. When the window is to be and light weight, the inventor expects it auto- theory that levers attached to heavy locked open three inches at bottom or to be used widely in aircraft. pro- rolling weights placed at intervals along top, the nuts are screwed to the top of “a —_— n the the rails would stop locomotives from Sneezing Plants Spray i the | colliding. Their Seeds into Air “king When two trains approach a crossing F ' at the same time, the inventor says, the ner ged plants that spray their nt, if weighted levers catch projections on the seeds into the air with each “ka- -inch rear of the locomotives and slow them choo are described by Herbert H. milk down, preventing them from crashing at Whetzel, professor of plant pathology at : the intersection. To lessen the strain of Cornell University, Ithaca, N. Y. a sudden stop, Oliver explains, the They are various types of destructive weights roll back sufficiently to bring the fungi: Their cup-shaped seed holders are trains gradually to a halt. filled with tiny pods, each containing eight seeds. In each seed pod is a charge of starch which ferments and explodes, Professor Whetzel explains. This explo- sion blows the microscopic seeds an inch or more into the air. They float about, land on plants, and take root. Professor Whetzel has obtained a photo- graph of a large number of pods explod- cibiiaine tends Generate ing at once, with a cloud of the seeds from rattling or being raised. swirling in the air above. the rod and clamped about the Wanted —Three-Eyed Fish! standard projection while in that position. When the win- ONE thing biologists want to see is a dow is locked shut, the nuts three-eyed fish. Dr. E. W. Gudger, are tightened near the lower of the American Museum of Natural end of the rod and the device History, New York City, has a photo- is locked to the standard. Ac- graph of a haddock with three eyes, but cording to the inventor thelock the original specimen never came under does not interfere with free scientific observation. Anybody with al TE tt one denass tate tie Meebeatiiaenns eaeeinanaalD working or cleaning of windows, a three-eyed fish should send it to the ll, down toy engines in peril of crashing at rail crossing. as it can be lifted off. Museum, preserved in formaldehyde.

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62 POPULAR SCIENCE MONTHLY _ Getting the Best Tone Mj from Dynamic Speakers How to Build a Simple and Attractive Baffle Board That Will Give Natural Reproduction of Radio Voice and Music By ALFRED P. LANE APRIL, 199 Fig. 1. Special acoustic ma- terial of cane fiber. Its sur- face is peppered with holes to increase absorption of sound. “WeM GETTING plumb discour- aged,” complained a radio dealer to me the other day. “There's some funny angles to this radio business, and the question of tone quality sure heads the list.” **What’s so funny about tone quality?” I asked him. “Well,” he explained, “it’s like this. Most of the birds that: drift in the former, the particle of air move back and forth in the direction the wave is traveling instead of across the line of mo. tion, as with water waves, A sound wave is simply series of rapidly expand. ing rings about the soure of the sound. Each ring is an area in which the air is compressed, and the space between the waves is an area in which the here to get radio receivers Fig. 2. tell me how they have very sensitive ears and how they’re chiefly interested in getting real true tone quality—and when I give it to them they don’t recognize it! “Here,” he added, snapping a plug in a wall socket, “‘just listen to this and tell me what you think of it.” After the tubes heated, the strains of a jazz band issued from the loudspeaker. “That's not so bad,” I observed. **Now listen to this one,” he growled, switching plugs, and in a few seconds the strains of the same jazz band came from another loudspeaker. . “That’s much better,’ I exclaimed, for the second trial was clean-cut and brilliant. All the low tones were coming through and the higher frequencies as well. It was a close approach to true musical reproduction, and I told him so. ** Of course it is,” he agreed, ““ but most people think that first set is better. ‘Beautiful mellow tone’ they call it. Mellow is right! Like a ‘mellow’ egg— soft and a bit ripe!” That dealer, who is an exceptionally good musician, was merely exaggerating a novel state of affairs that exists today. Many people actually prefer their radio music distorted; which is rather strange, because only a short time ago everybody was striving for good tone quality and condemning distortion. The difference lies simply in the fact that whereas the distortion formerly was caused by lack of the low frequencies, the ‘mellow’ form of distortion that appeals to some people How you can make an otherwise unsightly baffle board into an attractive screen for the living room. The shaped board is covered with light upholstery fabric. now is caused by leaving out or deliber- ately cutting off a large percentage of the higher frequencies. True tone quality, which means simply accurate reproduction of the sounds pro- duced in the broadcast studio, depends on many factors. As has been explained in previous articles in PopuLAR SCIENCE MonrtH iy, radio reception is like a chain that is only as good as its weakest link. The receiver must be capable of doing the job, the tubes must be in good con- dition, and the loudspeaker must be capable of converting the electrical im- pulses into sound impulses with the least possible distortien. RANTED you have a good receiver, the dynamic cone type loudspeaker is admittedly the most perfect form of loudspeaker, provided it is used under conditions that will permit it to do its best work. Unlike the ordinary magnetic cone, the dynamic cone speaker is only part of the cémplete loudspeaker equip- ment. The function of the vibrating cone of the dynamic speaker is to impart its vibrations to the air with which it is in contact. The function of the remaining part of the loudspeaker equipment is to see that these air vibrations are prop- agated into the air of the room without additions or subtractions. Sounds, as you know, are waves in the air. The only difference between sound waves and the waves in water is that in pressure is below normal, The cone of the loud. speaker moves back and forth as a complete unit and therefore acts like a piston. While it is moving in one direction it is starting a band of com. pression on one side and an equivalent band of low pressure on the other side, Two sound waves are therefore produced at the same time, one from the front of the cone and the other from the back. When these two waves meet at the edge of the cone, the high pressure area neutralizes the low pressure area from the other side, and the result is that no sound wave issues into the room. This effect naturally is much more pronounce on the long waves of the low tones than on the short waves of the high notes. This means that when a dynamic loud speaker unit is used alone you cannot hear the low notes because their energy is absorbed and canceled outright at the edge of the cone before it can be trans mitted to their of the room. HE obvious remedy is to prevent the two air waves from killing each other by keeping them apart. And thatis the function of the baffle board or cab inet which completes the loudspeaker equipment. The dynamic speaker baffle board is ia no sense a sounding board like that used in a piano to reinforce the vibrations the strings. Theoretically the baffle board should be incapable of vibration It is simply a partition to keep the front waves and back waves from with a It for tition. shown to pre Whi

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PRIL, 19y he T'S articles *k and Jon the Instead of mo. Waves, mply a Xpand. Source ch ring the air id the waves ch the 10rmal, > loud. *k and erefore ving in f com. valent r side, »duced ‘ont of back. at the e area _ from hat no This unced ; than tes, loud. annot nergy at the trans. event each hat is * cab eaker | is i used ns of baffle ition. » the from ApRIL, 1929 erminati each other. An ideal baffle inanld be one made of solid lead inch or two thick. But such a baffle would weigh about a ton, and the expense es make it impractical. — The use of a baffle board is, of course, the sumplest way for you to get good re- ylts out of a loudspeaker. However, other members of the family may throw : their hands in horror at the idea of wr ting a large and ugly board in the Fving room. Consequently, your problem js to overcome these objections while reducing a dynamic speaker baffle board Fhat will give the best tone quality. GURES 2 and 3 show a satisfactory solution of the problem. The baffle is made of two sheets of plywood with a layer of cane fiber board between. It forms an excellent soundproof par- tition. The cross bracing at the back, as shown in Fig. 3, gives rigidity and helps to prevent warping. ; ; While the design of this particular baffle board is attractive, there is no magic in the shape. You can change the top and side outline to suit your own ideas or to harmonize with other fur- nishings in the room. It is not necessary to have an ugly, gaping hole showing in the center of the baffle board, where the dynamic cone is fitted. The hole is there, of course, but it is concealed by a light upholstery fabric which is stretched over the entire board. Any sort of fabric can be used. Cotton print is good and also cheap. It will be well to let the lady of the house pick out the material. The rim of the board is covered with upholstery edging and studded with brass-headed upholstery tacks. Here, too, your own ideas may be allowed full play. The only important restriction in the design of the baffle board is a predeter- mined figure for the distance from the edge of the hole in the center to the nearest edge of the baffle. This distance governs the low note reproduction you will get. The rule is to make it not less than one eighth of the wave length of the lowest note you want to reproduce. OUND travels at 1,025 feet a second, and you can determine the length of a sound wave of any given frequency simply by dividing 1,025 by the tone fre- quency. A tone vibration of 100 would therefore be 1014 feet long. Dividing again by 8 gives a trifle less than 15% inches as the minimum distance from the edge of the baffle to the edge of the hole, if you want to reproduce tones down to one hundred a second. The smallest possible baffle board which would give you this frequency would therefore be a circle 39 inches in diameter, assuming that you have a nine-inch hole in the center in front of the dynamic cone. If you want to get down to 30 cycles, the baffle board would have to be nearly nine and one half feet in diameter. It must be understood that the effect of the baffle is not as sharp and definite as these figures would indicate. The 39-inch baffle would give you some response at 30 eycles, and so on. For practical use it is not necessary to make the baffle any larger than the one shown in Fig. 2, which measures 54 inches from top to bottom and 45 inches across. The radius of the . curved top was drawn from the center of POPULAR SCIENCE MONTHLY the hole for the cone and is half the width of the baffle. A screen baffle of this type, decorated to match the furnishings of the room, adds to the appearance of the room and is at the same time the simplest, cheapest, and least troublesome way of getting the best possible results out of any make of dynamic speaker unit. Note that cheap lumber from old crates can be used for the back bracing, since the back of the baffle does not show when placed in position in any convenient corner of the room. Many owners of dynamic cone speaker units have attempted to fit them into cabinets instead of using baffle boards. In most every case trouble is encountered with resonance effects caused by the air space confined in the cabinet. A most unpleasant and decidedly unnatural “bar- rel tone’ is produced. The tones in musical selections that coincide with the resonance period of the confined air in the cabinet are overemphasized. The music sounds as if it were coming out of the bottom of a well and the announcer sounds as though he had a throat about a foot in diameter. T IS possible to eliminate this trouble by fitting the front of the cabinet with a thick baffle board made of a sound- absorbing cane fiber material, which is sold in large sheets. Then the entire inside surface of the cabinet must be lined with the same material or with thick layers of felt. A special cane fiber board that has remarkable sound absorbing qualities has been developed for such purposes, as well as for use in cutting out resonance in broadcasting studios. A standard size piece of this material \ *% serene wwe 4 63 is shown in Fig. 1. Note that its surface is peppered with holes. These extend about three quarters of the way through. The theory is that the holes greatly in- crease the surface and consequently the sound absorption. Laboratory tests in ‘the Popular Science Institute of Standards show that the theory is well founded. HE effect of a cabinet on the dynamic cone loudspeaker should be the same as that of a baffle board. It should keep the sound wave from the front of the cone from annihilating the wave from the back of the cone. Theoretically, it would be fine if you could entirely eliminate the wave from the back of the cone. At first glance it would seem that inclosing it in a cabinet with no opening except the hole in the front would accomplish just this result. Unfortunately, it does not work out that way. Inclosing the air back of the cone will make the air act as a damper and prevent the free motion of the cone, with disastrous effect on tone quality. The back of the cabinet should be left entirely open, as shown in Fig. 4, to pre- vent this effect; or if the outfit must be placed where the back can be seen, then cover it with thin silk or cotton cloth of a color to match the cabinet. The effect of lining the cabinet with sound-absorbing material is to absorb that portion of the sound wave that strikes it and thereby prevent it from being re- flected back to cause resonance or “barrel tone” effects. Some readers may think that a baffle board applied to an ordi- nary magnetic cone speaker would result in an outfit just as good as that in Fig. 2. Thatis not so, because the ordi- nary magnetic cone is not capable of reproducing the low frequencies and because the magnetic cone has almost no piston action. HE effectiveness of a cabinet as a dynamic cone baffle is determined in the same manner as is that of the plain baffle board. The measurement is made from the edge of the hole in front, around the corner to the opening in back. If you are confronted with special problems in the construction of a baffle board, or in obtaining the proper mate- rials for lining a cabinet, address your inquiries: ‘Technical Editor, PopuLar SciencE Montuaty, 250 Fourth Avenue, New York City. L Fig. 3. Rear view of the board, with dy- mamic cone in place. Note cross bracing, which gives rigidity and helps prevent warping. It can be made of cheap lumber taken from old crates. Fig. 4 . To prevent un- natural “barrel tone”’ when the dynamic cone | F is placed in a cabinet, | # fit the front and line | the interior with sound- |' absorbing material.|) Back should be open.

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How to Hook a Phonograph to Your Set Useful Ideas for Radio Fans Electrical Pick-up Simplified —The Secret of Good Tone Quality—Special Receivers for Special Needs HE conventional method of hooking the electric phono- graph pick-up to the radio re- ceiver is to substitute a special plug for the tube in the detector socket. This method gives good results but is somewhat incon- venient because of the necessity of removing the tube each time you wish to shift-from radio re- production to phonograph record reproduction. The novel device pictured on this page gets around this diffi- culty. The special plug is placed in the detector socket and the tube prongs are inserted in the holes in the adapter. Then the special switch is mounted at any convenient point on the panel of the receiver and the phonograph pick-up is connected to the wire ends shown at the lower right in the illustration. The switch plate is marked “RADIO” and “PHONO,” and throwing the switch instantly changes from one to the other kind of reproduc- tion. What this special switch or the ordi- nary plug attachments accomplish is, of course, to connect the electric pick-up to the input terminals of the first stage audio transformer. , In sets where a jack is provided on the panel, into which the cord from the phonograph pick-up may be plugged, the same end is attained. To fit such a jack to your set, use a double-circuit jack (four-prong) and connect the P and B terminals of the first-stage audio trans- former to the upper and lower lugs on the jack. Then connect the wires that were connected to these transformer terminals to the remaining lugs on the jack. Make sure that when there is no plug in the jack the circuit will be restored by the contact springs, just as it was before you installed the jack. In other words, the P terminal of the transformer must be connected to the wire from the P terminal of the detector tube socket. Tone Quality from Records ODERN methods of electrical re- cording give us phonograph records that contain in the wavy grooves a remarkably true record of the actual music or speech. However, the electrical pick- up is no miracle worker. All it can do is to convert the mechanical motion of the needle into equivalent etectrical impulses, and the tone quality of the music issuing from your loudspeaker will depend on how accurately you amplify these impulses POPULAR SCIENCE MONTHLY This special plug and switch makes it possible to change instantly from radio to phonograph reproduction. IH A B C’s of Radio [ree component parts of a receiving set are made of materials chosen because of their ability to carry electric current or to resist its flow. Thus connecting wires are of copper, and condenser plates of brass or aluminum, be- cause these have little re- sistance to the flow of current, whereas bakelite, hard rubber, fiber board, wood, and glass are used to stop current flow. However, no metal is a per- fect conductor of electricity, and the insulators mentioned are far from being absolute nonconductors. Electrically, therefore, the only difference between con- ductors and insulators is that the former have low resist- ance; the latter high resist- ance. And the resistance of any insulator depends largely on how much moisture it ab- sorbs in a damp place. Glass absorbs almost none, while yntreated wood, highly re- sistant when dry, becomes a relatively poor insulator when damp. APRIL, 1999 to loudspeaker volume. If you haye an old-style receiver fitted with Poor audio transformers and your loud. speaker is of an obsolete type, the modern record will sound no bette than if played on an old-style, tip. horn phonograph. In any case, the phonograph recon} will sound no better than the radiy reproduction from the same pm ceiver. High quality reproductioy is the same problem whether the original sound impulses come from the detector tube of the receive or from the phonograph recon by way of an electric pick-w, This means that any radio receiver capable of giving good tone quality on broadcast music will do equa ly well operating from an ele. trical pick-up. The possible vol. ume without distortion, either on broadcasting or from phonograph records, is limited by the type o power tube that is used in the last audio stage of the radio receiving apparatus. Special Receivers HILE the radio demands of most people are supplied by the con. ventional radio receiver, there are many cases where a special receiver can he designed that will give more satisfac. tory results. For example, take the cas of a partly deaf person located reasonably near a number of broadcasting stations. To obtain sufficient volume from a loud- speaker to afford good hearing for sucha person would mean the use of a sé capable of tremendous volume on the loudspeaker. The volume would, in fact, have to be maintained at a level objec- tionable to anyone with normal hearing You couldn’t operate such an outfit in an apartment house without getting i ne with neighbors above and be ow. A simple solution is the construction d a plain three or four tube set consisting of a stage of radio-frequency amplifice- tion to provide selectivity, a detector, and one or two stages of audio amplification. Build it for storage battery or dry cel tubes, as desired, but do not bother with a power tube in the last stage and keep the plate voltage down to forty-five volts. That voltage on a plain tube will handle all the volume a pair of heat- phones will stand—plenty to afford good hearing to anyone not stone deaf. Elin inating the power tube, the high B-volt- age, and the need for C-batteries wil result in an inexpensive and easy-to-bui outfit. LR ED & \

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RIL, 1999 LS ou have ith poor r loud. ype, the > better yle, tin. h record 1€ radio me re. duction her the ne from receiver record Dick-up, receiver quality > equal. in. elec. ble vol. ther on \ograph type of st audio atus, of most 1e COn- e many can be atisfac. he case onably ‘ations. a loud- sucha a set on the in fact, objec: earing, t in an ing i id be. tion of sisting plifica- or, and cation. ry cel r with 1 keep ty-five tube ' head- 1 good Elin- 3-volt- s will - build Apnil, 1929 POPULAR SCIENCE MONTHLY: 65 Three Ways to Build a Radio If you have no home workshop, you can easily build a kit set on the kitchen table. All the tools you need are a long screw driver, wire - cutting piiers, soldering iron, and rosin-core solder. You Can Be Your Own Designer, Follow a Blueprint, or Assemble a Kit Set—Which? Here Is the Answer OU can tackle the problem of building yourself a radio receiver in any one of three different ways. If you understand what each component in the radio circuit actually accomplishes, you can design your own receiver. This means working out a cir- cuit that will meet your particular re- quirement, choosing apparatus based on the electrical characteristics of the parts available, and then proceeding with the construction and wiring of the receiver aceording to your own ideas. You can learn a lot about radio by following this method, but if you are a beginner, it is likely that the experience will prove costly and the results won't amount to much. The second way is to obtain a blue- print showing you how to build and wire the receiver and what parts to use. By using a PopuLtar Scrence MontTuiy radio blueprint you will be following this method. Such a blueprint does not save you any of the actual labor of building the receiver, but it does save you the trouble of figuring out a circuit and choosing parts for it. In other words, the designing is all done for you. If you accurately follow the blueprint and in- structions, you can be sure the finished receiver will give good results, because you will be duplicating the model receiver from which the blueprint was made. The third and easiest method is to purchase a complete kit of parts. This way is easiest because you don’t have to drill, saw, or file anything. All the parts By JOHN CARR are supplied down to the last screw and nut so that, in effect, you purchase a complete receiver in knock-down form. The front panel and the metal base both come drilled for the parts to be fitted to them. A package accompanying the kit contains all the various screws, nuts, and such small hardware, as well as special parts needed in assembling the outfit. An instruction booklet shows just how to proceed with the assembly and wiring. Assuming that you want to build a receiver, which method should you adopt? The first we can disregard, because if you are expert enough to follow it, you won't need advice. That leaves a choice be- tween the second and third methods, and deciding between them depends on a number of factors. SSENTIALLY it hinges on whether you like to do simple, home workshop jobs, such as drilling holes and using such tools as a hack saw or file in the opera- tions needed to fit the dials to the panel, the panel to the baseboard and, of course, the construction of the baseboard itself. If you already have a home workshop where you make things, the mechanical work of building a receiver according to a Poputar Science Monrtuacy blueprint will seem extremely simple. On the other hand, you may have no workbench and none of the necessary tools. In that case, to build a receiver requiring mechanical operations, you will have to purchase tools and find a place to do the work. Here is where the complete kit fits in. All the assembling can be done on the kitchen table as shown in the illustration. Since all mechanical onerations have been performed for you in advance, it becomes merely an assembly and wiring job, and the tools you need for this work are few. Of course you want a screw driver, pref- erably one with a long, thin blade. It will get down between other parts to tighten a screw where a short screw driver cannot be used. Then you will need a pair of wire-cutting pliers, both to cut the wire to the proper lengths and to hold the nuts while you tighten the screws with the screw driver. The only other equipment you need is a soldering iron and a supply of rosin- core solder. An electric soldering iron will be found very convenient and will save much time, but equally good work can be done with an ordinary soldering copper heated to the proper temyerature on the kitchen stove. HERE are, of course, inferior radio kit sets on the market, just as there are inferior complete radio receivers. Be- fore you buy, therefore, it will be well to write to the Popular Science Institute of Standards for information as to -which radio kits have been tested and ap- proved. You naturally want to know that the circuit of the kit set is good, that the parts are electrically and mechanically suited for use in the circuit, and that the parts are accurately made so that they will go together without trouble.

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66 England Seeks Fog-Proof Building Materials A BATTLE against the atmosphere is A. being carried on by Great Britain through its Department of Scientific and Industrial Research. At Watford, north of London, experts in the Building Re- search laboratories of the government are seeking better building materials to fight the crumbling effect of England’s foggy weather. Some gases of the air, notably carbon dioxide, combine with building materials to form acids destructive to stone and mortar. The damp climate of the British Isles is said to hasten such action. Re- cently it was revealed that Westminster Abbey, the Houses of Parliament, and other structures have been weakened by such atmospheric action. Since nothing can be done about the cliraate, scientists are seeking new con- struction materials less easily affected. One of the first steps was to test the limes ancl cements on the market. Samples of each were burned in a rotary kiln while one of the experimenters watched the dazzling mass of flames, and a pyrometer recorded the temperature at which the material was consumed. The lime and cement which burned and crumbled most slowly was considered the best to with- stand the action of the atmosphere. Another experiment determined the re- sistance of piers, columns, and walls made of brick. A compression-testing machine, electrically operated, exerted a pressure almost equal to the weight of the world’s largest locomotive upon them to find the strongest mortars and bricks. Discovers Vast Plateau on Brazilian Border FERTILE plateau, larger than the state of Maryland, was discovered recently on the border between Brazil and Dutch Guiana by a Brazilian army officer, General Candido Rondon, while making a survey of that unexplored region. After penetrating into the jungles north of the Amazon, he reports he emerged upon “a vast plain of rich pasturage.” Its extent, he believes, is at least 15,000 square miles. General Rondon was one of the men who accompanied Theodore Roosevelt down the River of Doubt. .POPULAR SCIENCE MONTHLY Testing the strength of a brick column under tremendous pressure in the laboratory. Top photo: An expert observes the effect of heat on samples of cement in a rotary kiln Apri, 1929 Physician Feeds Patient Through Pores in Skin pe ING back time perhaps a billion years, when the earth’s earliest inhabj tants, the protozoa, or unicellular ani. mals, absorbed food through their micro. scopic bodies, Dr. Karl Stejskal, a Vien. nese physician, recently demonstrated that the pores of the human skin will act as mouths, and that man may be fed through any part of his body. Confronted with the case of a patient whose digestive organs were diseased to a point where starvation was almost ineyj. table, Dr. Stejskal conceived the idea of rubbing essential foodstuffs into the skin of the man’s back. In this way, it is re. ported, he succeeded in injecting suff. cient sustenance to maintain life. Ten ounces of fatty foods, nearly an equal amount of sugar, other carbohy. drates, and six ounces of protein were fed to the patient in this novel manner. Zoologists Seek to Save Whale from Extinction bps are in danger of extinction, according to Dr. A. Brazier Howell, zoologist at Johns Hopkins University, Modern power boats and improved equip- ment, he points out, have increased the catch until nearly 30,000 of the oil-pro- ducing mammals are now killed each year, whereas, during the entire forty years when Yankee whaling was at its peak, not more than 100,000 whales were killed. Except for the finest grade of lubricat- ing oil, such as is used in scientific instru- ments, whale oil is not needed. Dr, Howell: believes substitutes should be found in order to decrease the annual kill. He is secretary of the American Society of Mammalogists, the aim of which is inter- national action to save the whale. Six-Ton Slate Block Hoisted from Quarry OISTED like a fish at the end of a long line, a six-ton block of slate recently was removed from the bottom of an 800-foot quarry in Pennsylvania. Subsequently the slate was cut up into small pieces for roofing. Workmen with thin, broad wedges split out the layers. So great is the waste in preparing slate for market that seventy-five percent of the product brought from the ground has to be thrown away. ‘The mountains of material visible behind the slate block in the picture are part of the waste dis- carded during operations of the quarry. About half the slate quarried in the United States comes from Penn- sylvania. Walnut Trees Kill Plants S EVERY woodsman knows, vegetation will not grow under walnut trees. A chemical poison exuded by the walnut tree is re- sponsible, Everett F. Davis, of the Virginia Agricultural Experiment Station, has discovered. He suc- ceeded in isolating this substance, which he has named “juglone.”’ The huge six-ton slate block lifted 800 feet out of a large Pennsylvania quarry. In the distance may be seen great mountains of waste from the quarry.

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ction, owell, ersity, equip- od the -pro- i year, years k, not ad. ricat- istru- Dr. d be 1 kill. ty of inter- apnit, 1929 Researchers Baffled by Six Radio Mysteries R= researchers are looking for answers to numerous questions, among them ones such as: Is there any difference between trans- mission of radio waves in the direction of the earth’s rotation and the other way about? Some recent Marconi experi- ments indicate that there is. If so, why? Does it make any difference to the radio waves whether they travel along or across the earth's magnetic field? Why is transmission Over water easicr in some parts of the world than in others? Is there a limit in wave length beyond which transmission over land is prac- tically the same as over water? What causes the ionization of air to form the Kennelly-Heaviside layer? And do radio waves above a certain f requency penetrate that layer and then fail to return to earth? Who can answer these questions? Tear Gas Warns of Poison HE inclusion of tear gas in poisonous fumigation used to kill microbes and rodents on vessels is suggested by the U. S. Public Health Service. A slight amount of this gas, the Service points out, will serve as a warning to persons who may be in the holds and thus prevent fatalities. Experiments have shown that small amounts of tear gas are harmless and will give warning in time to allow escape from the poisonous products used in the fumigation of vessels, Sandbags to Strengthen Wrists of Pianists IANISTS can play better if they sus- pend sandbag weights from their wrists during practice periods. ‘This is the belief of Huston Ray, a musician of Los Angeles, Calif., who has devised a unique aid to piano students in the form of six-pound leather bags weighted with sand. The principle, he says, is the same as that employed by the Greeks, who car- ried weights while practicing jumping for ag q roe Huston Ray puts sandbags on pupil’s wrists to give strength in hitting the piano keys. POPULAR SCIENCE MONTHLY their Olympic games. The removal of the sandbags, Ray declares, has the effect of “giving wings to the fingers,” while their continued use strengthens the wrists and fingers, enabling the player to attain more power in the fortissimo bars of a composition. Divider Slices Pies into Cuts of Equal Size AKING the guesswork out of cutting pie and cake, a new device assures restaurant patrons that they will receive pieces of equal size, says its maker. The pie or cake to be cut is held firmly upon a turntable by adjust- You’ll get your full size slice of pie if it’s cut by this machine. able fingers. After an index lever governing the number of cuts has been set, a knife slipped into the blade guide slices out the pieces, a lever moving the turntable ‘ahead after each movement of the knife. The index lever permits the pastry to be divided into from three to thirty-four equal cuts. If it is desired to change the bulk of the pieces at any time, the index levet can be set to increase or decrease their size by altering the number of cuts. Pastries from seven to twelve inches in diameter, and up to eight inches in height, are handled by the machine. The maker adds that the device satis- fies customers because all get equal cuts and, as the moving parts are simple, the machine is easy to keep clean. Want White Hair? Then Use X-Ray ‘“‘Bleach”’ y YOUR hair turning prematurely gray? ‘Then it’s a pretty safe guess that one of your parents had hair of a color diferent from yours. At least, that is the conclusion reached by zoolo- gists of the University of Pittsburgh after a series of tests they conducted to ascertain why the hair of some persons turns gray or white sooner than that of others. The experiments were made with a number of mice. Exposing them to X-rays, which will turn hair permanently white, the zoologist found that young mice with coats of the same color as those of both their parents showed the greatest resistance against turning white, while those with parents of different colors were “bleached” in short order. = = : 2 Paints *‘Einstein’”’ Pictures of ‘“‘Energy”’ in Art RT paintings that display moving, animated figures, to the accompani- ment of a grinding noise of machinery, are the invention of Alexander Archi- penko, Ukrainian artist. His new form of art, which he styles “Archipentura,”’ was exhibited recently in New York. A special machine, used to display his unique creations, consists of 110 hori- zontal rollers, each bearing a strip of painted canvas, and arranged one above another so that a whole composite pic- ture results. When the machinery com- mences to whir, the rollers turn and new forms and colors appear. The invention, Archipenko says, offers new possibilities of depicting energy in art. However, the paintings are laborious to make. It takes 200 hours to reproduce the myriad small studies required for the canvas. A machine for home use might cost $50,000; so far there is only one in existence. Spectators saw changing scenes merge into one another in a demonstration of one of Archipenko’s unique canvases. First appeared colors spreading as oil on water; then followed in quick succes- sion an Indian blanket pattern, a female figure waving an arm, a lavender cone, another figure whose costume changed color, a checkerboard, a vase of flowers on a table, and a panel reading “Dedicated to T. Edison and A. Einstein.” Sees ‘“‘Magic”’ in Medicine ITH all the advance made by science, medical practice still deals largely in magic, in the opinion of Prof. Lynn Thorndike, noted historian of Columbia University. “A confidence game is practiced on the patient, who must be cheered and distracted,” he says. Sending a man to Florida or out to play golf is on a par with the ancient practices of the medicine men, but both inspire confidence that the patient is going to get well, Thorndike declares,

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Dials Show Time-Table of Trains at a Glance ERSONS who have difficulty in figuring out the intricacies of a time- table will be interested in an automatic device which is a unique feature of the Piccadilly Underground Station, recently opened in London. A complete time- table is always before the eyes of pas- sengers waiting for subway trains. Six dials record not only the time trains on the various lines are to arrive, but also their actual position at the moment. If a train is late, its progress along the rails can be followed by those n the waiting-room. The new Piccadilly station, the heart of the London tubes, was designed to accommodate 50,000,000 passengers an- POPULAR SCIENCE MONTHLY for just such an emergency. There are kitchens, stoves, beds, chairs, and other articles to make a temporary sojourn reasonably comfortable for a force of men. Descending by electric elevators, one has to pass through six steel towers with revolving doors, operated by elec- tricity, to reach the vaults. In case of serious trouble, the elevator shafts can be flooded. The walls and doors are of steel and concrete, twenty feet thick. But if, despite all these precautions, an enemy should succeed in penetrating, there are ultimate means of defending the gold reserve which remain the secret of the French government. Folding Bicycle Carried Newspapers from Cornstalks APRIL, 1929 Editors in Danville, Ill., examine the first newspapers printed on cornstalk-pulp paper, EWSPAPERS, magazines, and book, recently made from com. stalks, represent the latest step in utiliz. ing waste products of the farm. In the pressroom of a newspaper plant at Dap. ville, Ill., cornstalk paper was tested for the first time in actual competition with wood-pulp paper and the results are said to have proved satisfactory. Further tests are being made, to determine whether large-scale production of the cornstalk- pulp paper will prove economical. The newsprint made from cornstalks js said to look exactly like wood-pulp paper, but to be of stronger texture and to be very white, taking ink clearly, The first book printed on paper made from what has been a waste product of Aprit nually; 1,600 trains pass through it Like a Typewriter farms in the past 1s, appropriately, a y every day, on the average. COLLAPSIBLE bicycle which can volume on “Farm Products in Industry,” In the picture above, one girl is show- be ridden to a station, folded up, and by George M. Rommel, who recently ing two others how to “see how they run” taken on a train in a small suitcase has made a survey of farm waste for the U.§. 7 as recorded on the station’s dials. been brought out by a French bicycle Department of Agriculture. Po maker. He expects it to be popular tim Underground Gold Vault a wos Anactorseigge have we we * The Same Old Money, but goc * ’ + ae eir apartments to store a full-size : : Rivals Hugo’s Fiction waver Pe but would like to ride a bicycle in Smaller Paper Bills his I WHE fiction of Victor Hugoand[Eugene to work or to and from the station when LL of us, no matter how blessed with the Sue, in which thrilling and myste- traveling. Commuters also are expected this world’s goods, soon will have ] rious doings in the maze of sewers and __ to find special use for the bicycle—they less money. The new currency to be tes tunnels underneath Paris are described, can ride on it to the railroad station in put in circulation this year will measure of has been rivaled by fact. The Bank of the morning, check it, and pedal home six and five sixteenths by two and eleven ves France, after three years of work by again in the evening. sixteenths inches. Our present bills tot nearly 1,500 men, has completed con- In spite of the small size of the wheels, measure seven and three eighths by cur struction of a subterranean hiding place _ it is said the machine is geared sufficient- three and one eighth inches. Sve for the $1,000,000,000 gold reserve of ly high to attain a speed of twenty miles On the whole, the smaller money will ] France which, for imagination of design an hour on level ground, and that it is present the same general appearance as ha: and ingenuity of construction, sur- constructed strong enough to support a that now in use. One difference will aan passes anything conceived by those man of more than the average weight. @ new distinctive paper which the 801 famous romancers. Treasury Department announces will no Two hundred feet underground the gold chamber containing the secret vaults covers an area of two and a half acres. It is separated from the street surface by forty feet of water and fifty feet of rock, the have greater endurance than the old. A small amount of silk is now used in our bills. This feature will be con- tinued, but instead of being concen- trated in rows, the silk threads will be distributed over each bill. latter forming an arch over the for water, through which a secret sys- Information Available ha tem conveys the air supply. In the me event of war or revolution, more oer Scr—encE MontTusLY sal than 1,000 men, safe from bombs is glad to supply, whenever pos th and gas attacks, could be accom- sible, the names and addresses of ap modated in the spacious under- manufacturers of devices men- se ground rooms to guard the nation’s tioned in its pages. Address all m treasure, even though the bank requests to the Information Editor, bi itself should be demolished overhead. A traveler can pack this tiny collapsible bicycle into a small PoputaR Science Monruty, 250 su Food is kept constantly on hand suitcase and carry it with him no matter where he goes. Fourth Avenue, New York City. ye

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PRIL, 1999 ks the first P paper, and 4 m corn. In utiliz. _ In the at Dan. ested for ion with re said to her tests whether — stalks is »0d-pulp texture clearly, er made duct of ately, a dustry,” recently he U.§, . but IIs ed with ll have to be neasure | eleven it bills ths by ey will Ince as will be h_ the ces will he old. v used ye CON- oncen- ds will ble ‘T HLY r pos ses of men- ss all itor, , 250 y. Apnit, 1929 How the new safety gate appears when up. It drops automatically as train nears. Mail Carrier Has ‘‘*Circled Earth’? Seven Times ALKING a sufficient number of miles within the city limits of Balti- more, Md., to have circled the globe seven times and have 4,000 miles left over for good measure is the remarkable record of a mail carrier who has just decided that his feet need a rest and has retired from the postal service. John E. Ruark, the Maryland “globe- trotter” in question, marched an average of fifteen miles a day, 306 days in the year, for thirty-nine years, making a total of 179,010 miles. The earth’s cir- cumference, in round numbers, is twenty- five thousand miles. In this long period of service, Ruark has carried about 24,000,000 pieces of mail, or thirty letters for each one of the 800,000 men, women, and children who now inhabit Baltimore. Pedals 175,000 Miles on Bicycles in 20 Years EARING out three bicycles in twenty years, Charles A. Stoops, former Chief of Police at Easton, Md., has pedaled 175,000 miles, more than most motorists would drive a car in the same length of time. Statistics show that the average automobile owner drives approximately 8,000 miles a year. Sixty- seven years old, Stoops covered 8,780 miles last year and, although his earlier bicycles did not have cyclometers, he is sure his average mileage in the preceding years was higher. POPULAR SCIENCE MONTHLY Crashless Crossing Gate Bends Like a Bow NEW safety railway crossing gate, shaped like a violin bow, is designed to prevent motorists crashing through onto the track, as occasionally hap- pens with ordinary wooden gates. The “string” of the bow is composed of two tightly stretched steel cables supported by a frame of spring steel forming the curved bow. Between the “string” and the “‘bow” is a space of five or six feet to allow the cables to give when struck by moving automobiles. The cables face the motorist as he approaches the crossing. When the gate is lowered, a loop at the end of the bow drops over the post of a hydraulic snubber. This snubber is ca- pable of moving back six feet. The im- pact of a colliding vehicle, after bending the bow, forces back the snubber, thus easing the blow. The device is said to have stopped a 4,000-pound car, travel- ing thirty miles an hour, within three and a half feet without damaging either the machine or the gate. The safety of motorists who find them- selves trapped between lowered gates is also provided for in the new barrier. While the locking device on the snubber post prevents the closed gate from open- ing toward the track, it does not inter- fere with opening it in the opposite di- rection. Thus the trapped driver can force the gate with the nose of his car. The operation of the gate is’ entirely automatic. Electric circuits keep it closed as long as a train is in the danger zone, thus preventing motorists from rushing on the track in front of a second train after the first has passed. The weight of the gate is so evenly balanced that it can descend upon an automobile without damaging the top. A Riveter for 50 Years, He Claims the Record F YOUR nerves jump at the staccato noise of the riveters at work on a new steel building, you can appreciate some- thing of the job of Edward Fay, of New York City, who listens to that music almost every day. He has been a riveter for fifty years. Fay, who is sixty-five years old, claims the distinction of being the oldest riveter still on the job. His co- worker, F. Smith, has held rivets for Fay for the last thirty years. Edward Fay (right), veteran riveter, and his partner who has held-rivets for him 30 years. 69 When a car hits the gate, the steel “‘string”’ of the bow gives, and a snubber lessens shock. Smallest Torch Reveals Microscopic Life HE world’s tiniest torch—a light so small that it will illuminate the inte- rior of a single living cell under a micro- scope—is proving an aid to laboratory investigation at the University of Pitts- burgh. The instrument consists of two pencil-shaped pieces of quartz put to- gether like pincers with the points, which were drawn down finer than those of needles, coming together. As a result of quartz’s unusual affinity for light, a violet ray introduced at the large ends of the “pincers’”’ legs will be carried to the small ends, which then are used to light infinitesimally small frag- ments of matter placed under the micro- scope for examination. With the new device, called the “mi- croradiator,” investigators are enabled to penetrate into the heart of single cells and study processes in the growth of living organisms. Gas Masks to Be Used in Fight on Hay Fever ERMAN scientists have adapted the gas mask of World War fame to use in the battle against flower pollens that cause hay fever and which are believed responsible for asthma. The new mask filters the pollen out of the air just as the war mask did poisonous gas. How fine is this filtering process may be realized from the fact that the grains of some of the troublesome pollen are less than a millionth of an inch in diameter.

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70 Aerial Camera Snaps New Canyon Bridge OW a man-made spider’s web appears to a man-made bird is revealed in a remarkable photo- graph taken recently from an air- plane flying above the Marble Gorge of the Grand Canyon of the Colorado, in the northwest- ern part of Arizona. It shows the steel span of the new highway bridge being completed across the Gorge below Lee’s Ferry. In a region of untamed scenic grandeur, 135 miles from the near- est town, this span, 616 feet long, has been erected at a cost of $330,000 to open up hitherto in- accessible regions in Arizona and Utah for tourist travel. The bridge reaches out over the can- yon with a sheer drop under it of nearly 500 feet to the waters of the swirling Colorado River. Some of the tremendous obstacles which engineers were forced to overcome in its construction were related not long ago in PoruLar ScrencE MonTHaty. Detects Secret Message by Shading of the Ink TF EVER you have occasion to include a secret message in a letter be sure to write the entire missive with a well-filled fountain pen and not with an ordinary pen which has to be dipped into ink. A British handwriting expert discovered the other day that part of a letter consisted of a secret message by studying the manner in which the writer had replenished his pen. The letter was written from beginning to end in plain English and contained no code symbols nor cryptic language of any sort. But the expert saw that a certain paragraph had been copied, while the rest of the missive was the writer’s own spon- taneous expression. When we write down our own thoughts, we unconsciously dip our pen at the end of each sentence, the first letter of the new sentence becoming heavier as a result. But when we copy, the pauses and blacker letters occur more frequently. By recognizing this fine dis- tinction in shading, the hand- writing expert was enabled to locate the secret message, which he finally decoded. Gunny Sacks from Banana Trees ) | pony trees may yield fibers to take the place of jute in the manufac- ture of gunny sacks used to carry produce all over the world, if hopes of Brazilian textile men are realized. An invention for utilizing the tree fibers for this purpose was described recently at Rio de Janeiro. Brazil imports nearly $6,000,000 worth of jute every year. It is used mainly in the shipping of coffee. The plant from which jute, some- times called “Calcutta POPULAR SCIENCE MONTHLY A magnificent photograph of the new highway bridge across Marble Gorge, Grand Canyon, taken from an airplane flying above. The bridge is almost five hundred feet above the water. hemp,” is obtained is grown chiefly in India and, to a limited extent, in China, Formosa, and southern Japan. Partly successful attempts have been made to grow it in the South Atlantic and Gulf sections of the United States. Attempts to naturalize it elsewhere have failed, so the supply is limited and a substitute in the form of tree fibers would mean a great saving to shippers. A Trainload of Gasoline Goes Up in Smoke $60,000 pillar of smoke darkened the sky at Zyba, Kansas, following a recent railroad wreck in which twenty- seven tank cars, filled with gasoline, jumped the track, piled in a tangle, and burst into flames. All of the valuable cargo, on its way north from the oil fields of Oklahoma, was destroyed by the fire. The photograph below, taken when the fire was at its height, shows the immense cloud of dense black smoke that rose from the burning gasoline. * son 9 mente ig A ee Thousands of gallons of gasoline burning. This spectacular fire followed the wrecking of a train of twenty-seven tank cars on the Kansas prairies. APRIL, 1939 Lower California Is | Rising from Sea OWER California is ily rising from the sea, accordi. to a report of the National Geo. graphic Society. The area Of the fingerlike peninsula, surveys hay shown, is increasing, while the Gulf of California, Separating jt from the mainland of Mexico, jg losing width and depth. Such rising and falling of the earth’s surface go on continual} as a result of shifting weight dye to erosion and other causes, }j the earth were rigid, the report declares, and did not react to the weight of ice sheets and the grind. ing of waves, there probably would be no dry land today, but instead, an ocean two miles dee, covering the whole globe. The continents are believed ty be masses of relatively light solid matter, floating on hot, glassy material forty or more miles be. low. The ocean beds are believed to be underlaid by heavier solid matter which does not float as high as the continent material. The earth’s surface is constantly being dis turbed, so it must bulge in one place and sink in another to regain its balance, somewhat as a tight-rope walker fling out an arm or draws it in to restor equilibrium. The Grand Canyon of the Colorado is believed to have been formed by a bulging movement that caused land to lift gradu. ally against the flowing river. Thus is the great depth of the Canyon accounted for. Other parts of the earth are known to be rising or sinking. Southern Denmark drops an inch every twenty-five years while portions of the upper Baltic region rise a foot every thirty years. Light from Tumbling Suns Arrives in 800 Years N THE year 2729, some astronomer will be able to ascertain whether two giant suns, which were seen rolling around each other in space a few weeks ago, actually existed in 1929, when they were observed for the first time, or whether they passed out of the universe centuries before The light of these two stars, seen recently by astronomers at the Mount Wilson Obsery- atory, in California, takes 800 years to reach the earth, so there is no way of telling whether they still exist. What the astronomers did establish, however, was that they tumbled about each other, that one was more than five times as large as our sun, but weighed less than twice as much; that the other was three times the sun’s size, but was six times as heavy; and that they were a mere 9,000,000 miles apart, which is a rather neighborly distance as such matters go in space, for we are separated from our sun by about 90,000,000 miles. Apri Fur mal effic fort oce elev pla: swt

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rea, of the 'veys hay, while the arating it eXico, jy Ng of the ontinually eight due auses, J} he Teport uct to the she grind. Probably day, but, ‘iles deep lieved to ght solid L _Blassy miles be. believed ‘ler solid float as onomer ier two around ‘S ago, y were ime, or out of before. . Stars, omers bsery- takes earth, telling rs did ; that each more 1S OUr than the ; the times were part, porly "Ss go ‘ated bout ApRrIL, 1929 POPULAR SCIENCE MONTHLY War Birds Flit from Floating Nest Built Like Dovecote A British fighting plane rising from deck of airplane carrier Furious. In foreground is wind screen which can be raised, NE of the great floating Q) nests for war birds is the British airplane carrier Furious, which is equipped with many devices to increase the efficiency of machines flying at sea. The “roof” of the vessel forms the broad expanse for the oceanic flying field. From it, elevators lower and raise the planes to and from hangars and repair Shops provided to house them when not in use. When the Blackburn-Dart war planes, used to train naval pilots on the Furious, swoop to a landing their wings are folded back by mechanics before they are placed upon the elevators, so they will occupy less space in the vessel’s interior. To prevent planes from running off edges of the deck, when making a landing in bad weather, a heavy fence has been built around the far end of the landing platform. This guardrail is slanted out- ward at an angle so it can stop the Salamanders Grow Eyes “TYYELESS” salamanders, born in deep caves, develop eyes when reared in the light, according to G. K. Nobie and Sarah H. Pope, of the Ameri- can Museum of Natural History. The organs of vision, apparently lost, are merely dormant, they found. Huge Searchlight’s Beam Will Guide Air Liners OU can stand upright within an immense searchlight recently com- pleted in England for use at the famous Croydon Airport. It is seven feet six inches in diameter and, mounted on its platform, stands fourteen feet high. The operator of the huge night guide for passenger air liners sits upon a seat above the platform and directs the beam of light by means of cranks and gears. The distance the 3,000,000,000-candle- power light, said to be the most powerful ever built, penetrates through the dark- ness will be determined when the search- light is put into regular operation. Towering in tiers of hangars like a dovecote, the plane carrier is truly a huge floating nest. machines without damaging them. Heavy metal screens, swung up to break the force of the wind in gusty weather, shelter parts of the deck and give added protec- tion to landing pilots. During practice maneuvers, the ma- chines take off one after the other, each departing at a signal from officers in the control pit at the end of the runway, just as air liners take flight under direction of an officer in an airport tower. In charge A man can stand within the reflector of this giant searchlight to guide English air liners, Officers in the control pit signal the sea flyers when to take off. Special devices prevent planes from running overboard when landing in storms. _ of a flight commander, the pilots circle out over the sea in wedge- like formations of six, often flying hundreds of miles before spiraling down to a landing on the mother ship. The complete crew of this marine flying field includes 890 officers and men. Finds Babies Are Normal Despite Parents’ Ages HE ages of parents at the time of a baby’s birth have no bearing upon the normality or lack of it in the individu- al, nor does it make any difference whether one is oldest or youngest in a large family, Dr. Madge Thurlow Mack- lin, of the University of Western Ontario Medical School, recently reported as the result of extensive observation of 111 pairs of twins. If heredity caused defects in one twin it would operate the same way with the other of the pair, but defective individuals often have normal twin brothers or sis- ters, she found. Dr. Macklin also de- clared she had exploded the theory that worry or shock to the mother before birth has any effect upon the offspring. Whale Eats Millions of Shrimp for Lunch ESS than two dozen shrimp are needed to make you a satisfying salad, but the whale, largest animal alive, which curiously enough dotes on these little creatures, eats millions of them alive for his daily luncheon. A group of scientists just returned to England from an expedition to the Ant- arctic, now the greatest whaling ground, reported that the huge sea beasts there live almost exclusively on a variety of very small shrimp, which they swallow alive by millions. The shrimp, in turn, subsist on diatoms, tiny plants on the ocean’s surface.

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72 ‘ee 4 ~ 2% 3 Sia ‘ . . : Bathing Beauties Skate on Sunproof ‘‘Ice”’ KATING in bathing suits on a glaze of chemical ice that the sun cannot hk melt is the latest sport in the moving picture colony at Hollywood, Calif. Surrounded by palms and other tropical foliage, the skaters glide and circle in the joyous pastime of colder climates. After they have been in action for a time, the caretaker of the unique skating pond appears with a large hot flatiron and smooths the ice as one would iron a towel or a tablecloth. This is done periodically to remove rough spots the sharp skate blades cut in the hard, pol- ished surface. If the fad spreads, “ice ironing” may be a vocation of the future. The synthetic “ice’ was developed and laid by Arthur R. Maas, a chemical engineer of Los Angeles. A framework covered with heavy screen wire is con- structed as a first step. Over this the chemicals, dipped from a caldron with a long-handled dipper, are slowly poured. They cool and harden quickly, forming a surface that appears like real ice, al- though it is unaffected by a blazing mid- day sun. Similar skating rinks of synthetic ice are used in Germany, as was reported in a recent issue of PopuLar ScIENCE Monta_y. The imitation ice used for the German rinks, however, is formed from solid chemicals sprinkled over a wooden floor. They harden into a smooth surface on which the skates have little effect. Double-Walled Pot Keeps Flowers Watered DOUBLE-WALLED flowerpot, the inner part porous and the outer waterproof, with’ the two united at the top by a flat rim, was described recently by Dr. J. Dean Wilson, of the Ohio Agri- cultural Experiment Station, who said thet extensive experiments proved its usefulness in automatically irrigating plants growing in it. Infra-red light, composed of rays longer than the red of the visible spec- trum, have no effect upon leaves, in the opinion of Dr. J. D. Sayre, of the same experiment station, but ultra-violet light, the invisible rays at the short-ray end of the spectrum, have a stimulating effect. ~ . POPULAR SCIENCE MONTHLY Amidst a tropical setting of cooling palms, hot irons are used to smooth the sun- defying ‘“‘ice’’ over which Hollywood’s screen beauties glide in bathing costumes. di, ~ f\ foe '/ \ x ‘ A. R. Maas pouring boiling chemicals over a meshed wire framework to “freeze”’ his summer skating pond. \ / “i Xe ‘ \ es? ee ~p* ‘e = Oye el 4 ae Nz 5 . One Twist of the Wrist Sprinkles 10 Acres IKE turtles drawing in their heads and closing their shells, automatic sprin- klers installed recently in the sheep mead- ow at Central Park, New York City, disappear into the ground and pull tight coverings over themselves to give the meadow a smooth surface when the water is shut off. By turning a single valve, park workers can sprinkle the ten- acre meadow. John A. Brooks, inventor of the unusual irrigating system, was present when the sprinklers were tried out for the first time to demonstrate that their action is entirely automatic. When the water is turned on, the spray heads rise above the ground. When the water is shut off, they drop into under- ground casings protected’ by covers and remain in this position until used again. APRIL, 1999 Chicago ‘“‘Hub”’ for Planes Flying 565,406 Miles VER the airways that | O Chicago like the epekes att wae mail, passenger, and express planes fy 565,406 miles a month. Fourteen aan panies, according to the American Ai, Transport Association, operate lines out of this one city. Most of this mileage jg rolled up by mail planes, but the Passep. ger service taking off from Chicago fields totals 106,000 miles a month. An innovation in passenger plane equipment will be installed as part of the air-rail service of the Transcontinenta] Air Transport Company this spring Radio telephones, similar to those used on the London-Paris air liners, will pro. vide direct communication between the pilot and the ground at all times, says ¢. M. Keyes, president of the company. Tiny Camera Photographs Inside of Stomach r INY camera, which takes sixteen pictures of the inside of the stomach on films with a total area less than that of a postage stamp, was swallowed re. cently by a convict at Sing Sing Prison, New York, in a demonstration before a meeting of medical men. The instru- ment, known as a gastro-camera, was designed by Franz G. Bach, of Vienna, Austria, to aid physicians in diagnosing stomach disorders. The minute films are capable of great enlargement, so that the exact location and character of gastric ulcers can be determined by surgeons before operating. Sixteen lenses, in two tiers, encircle the camera, which is like a cylinder about two inches long and half an inch in diameter. The sixteen negatives give a complete picture of the inside of the stomach. A single filament wire, inclosed in quartz glass, furnishes the illumination. This portion of the instrument is inclosed in a rubber case, perforated so light is thrown in the same direction the lenses point. The rubber tube, which extends from the patient’s mouth, carries current to this lamp from a storage battery. Patients go without food just before pictures are taken and air is pumped into the stomach before the camera is swallowed. ‘The whole operation of taking the internal photographs is said to require but a few seconds. Turning on the new sprinklers which rise automatically from ground to water the ten-acre sheep meadow in Central Park, New York. John A. Brooks (right), is inventor of the disappearing sprays.

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IL, 1929 anes Out of t wheel, mes fly Nl Com. Nes out leage js Passep. 50 fields plane t of the Anenta] spring, ill pro. en. the says (, ny. aphs sixteen Ltomach in that ved re. Prison, efore a instru- a, Was jenna, nosing ms are > that gastric rgeons cle the about ich in give a of the closed ation. closed ght is lenses ‘tends urrent nefens imped cra 1s n of aid to ApRIL, 1929 Church Manufactures Its Stained Glass Windows ED glass windows which beauti- ged seedioveal cathedrals, though ex- quisite in coloring and design, were not meant primarily for decorations, but rather were intended to serve the purpose of pictured story books at a time when illustration was confined principally to illuminated initials in manuscripts. These windows graphically told the worshipers of the lives of the saints and other reli- gious —_— the church wished to : upon them. Oe cocting to this olden practice, the builders of the great Protestant Episcopal Cathedral on Mount St. Albans, at Washington, D. C., will install an ex- tended series of beautifully colored win- dows which will relate virtually the entire story of Christianity and the influence it has exerted on mankind. Designers of the Cathedral also are following another example from medieval times, when the church was the mother and chief patroness of the arts. They have established their own stained glass plant at Philadelphia, where, under super- vision of noted artists and experts, the t rose windows and other glass adorn- ments for the Cathedral are being made. Many Uses Combined in One Watering Can NOVEL watering can designed for half a dozen uses is now on the market. A spout at one side equips it to fill automobile radiators. A two-by- eight-inch perforated mouth on the other side is a sprinkler for gardens and lawns. It helps in washing automo- biles, too, the maker says, as it fur- nishes a steady, gentle shower with- out splashing. Applying liquid fertilizer to plants is another job for which the device was planned. If insects attack vines or plants, it can be used to spray in- secticide through the perforated mouth, it is said. When it is not engaged in any of these tasks, or in dampening golf greens, the can goes fishing in the capacity of a minnow pail. You can sprinkle the garden, spray insects, or wash autos with this novel watering can designed for many outdoor tasks. POPULAR SCIENCE MONTHLY 5 : ; 5 ' i sce. Treadmill Prancing Trains Postmen to Walk EACHING postmen how to walk may sound paradoxical, but teaching them to walk hygienically is a positive boon to them and to the public they serve, according to a Chicago foot specialist, Dr. J. C. Rintelen, who recently gave les- sons to sixty letter carriers in Norfolk, Va. Using a treadmill, the postmen were instructed to “keep the feet straight ahead—don’t toe out—take brisk, snappy ‘Jointed Handle Is Aid in Stamping Y PROVIDING play be- tween the handle and mounting, a rubber joint in- creases the ease with which a new stamp can be used. It allows the handle to be held at different angles without marring the impression. In the ordinary rubber stamp, with rigid handle, care must be exercised to keep the stamp horizontal or its im- pression will be blurred or incomplete. The improved device, the maker says, speeds up the work of stamping. steps—swing the arms freely—stand erect.’’ They also were shown the correct posture for rapid walking. Canadians Will Use Peat To Reduce Coal Bills EAT fuel will be prepared for the mar- kets of Ottawa and Montreal, Canada, in a government plant at Alfred, Ont., which is practically automatic. It will operate twenty-two hours a day and turn out 20,000 tons of peat “bricks” during the winter season of 100 days. Except wood, peat is the only natural fuel found in quantities in the provinces of Ontario and Quebec. The Department of Mines of Canada has surveyed, mapped, and sampled more than 250,000 acres of peat bogs in the two provinces. It es- timates that these bogs will yield peat in excess of 250,000,000 tons, thus reducing the amount of coal that must be imported. Snake Bites Killed 27 in U. S. in a Year WENTY-SEVEN persons died of snake bite in the United States in 1928, according to R. H. Hutchinson and R. E. Stadelman, of the Antivenin Insti- tute of America. Five hundred and seventy persons were victims of different varieties of poisonous serpents. Of these 159 were bitten by copperheads in twenty-one states, thirty- eight by cottonmouth moccasins, seven- teen by the pygmy rattlesnake, seventeen by the swamp rattler; ninety-five by the true rattlesnakes of the diamond-back, or Texas, variety; forty by timber rattlers, thirty-eight by prairie rattlers, twenty- seven by Pacific rattlers, eleven by the eastern diamond-back, and four by desert “* sidewinders.”’ Four hundred and one of those bitten were treated with antivenin serum, which neutralizes the “‘venin” or poison in snake venom, and only eleven died; of the 169 cases untreated, sixteen died.

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ITHOUT comfort, no matter how economically it may be built or operated, a home be- comes a mere shelter from the elements. In recent years, American builders have been striving more and more to make houses livable and healthy. And in accomplishing this they have found insulation to be one of their principal aids in barring out cold in winter and heat in summer. When all architects, builders, and home owners realize the importance of insula- tion in construction, the noninsulated home will be on a par with one that lacks plumbing or is lighted by candles. A striking example of how insulation may be used to add com- fort in summer and win- ter is afforded by a cot- tage I saw recently at Riverside, Connecticut. Designed by F. Nelson Breed, a New York architect, this rambling story-and-a-half bunga- low type home has a 2 northwestern exposure swept by winter's bitter- | est gales. The lot on which it is built borders Long Is- TL land Sound, has few trees to break the force of wintry gales or offer shade from the mid- summer sun. But it is a aor a2 re =r FLOOR Carefully insulated against extremes of wind and weather, this ra Connecticut house on Long Island Sound stays comfortable through the year, Locking Out the Heat and Colt A Home Builder Finds Improved Insulation Soon Pays for Itself in Comfort and Lower Fuel Bills By WILLIAM DEWEY FOSTER home of your own, you’ll be interested in this article, the first of a series by distinguished American experts, based on the actual experiences of house build- ers who have solved the problems that every prospective home owner must face.—The Editor. [ YOU are planning to build a delightful spot in summer and the owner knew that the house could be made com- fortable for winter, no’matter how severe the weather, if it were properly built. In addition to the natural exposure of the site, the problem was made more diffi- ae . aie on Floor plans of the oultiee pictured at top of page. The many exposed walls and large roof area of the house presented unusual problems of insulation against heat and cold. POPULAR SCIENCE MONTHLY pr igi LiviAc- Room 319 Room F] . ] 20-0 + 3-0" nore oe" 3 4 Losacananpal sme =) — _ PSN: ae E a iL cult by the fact that the architect wa asked to design a rather low, rambling house. This meant that there must bea unusual amount of exterior wall surface, with the living rooms, kitchen, and thre bedrooms on the ground floor. Also it meant a large roof area for a compat tively small house, since it must spread over so much ground. Both architect and owner realized it would be necessary to insulate the build ing if it was to be made comfortable in winter and if the cost of running the heat- ing plant was to be kept within reason, but there was little money available for luxuries. The owner always had thought of insulation as a luxury, a kind of extn detail. Mr. Breed, how ever, pointed out that insulation would mean economy, particularly ia this house because of its exposure. The owner decided to get more information about the different im sulatihg materials then used. He remembered that a friend had told him of having his new# house insulated, but he also remembered _ that that new house was t0 have seventeen room and a four-car garage, and he felt that insul# tion was as much beyont 5° g3224 sea Soe 6& i a So SF 2 , - . — SEETELGLSEL ASTRGGLE Ev ELS LELEE GE EPERRERERES FREER ELERRESE SO BERSESERZAESIER.F § into

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"RIL, 1999 is rambli ch the yen ld anil ram ist bean surface, nd three Also it ompata- t spread alized it 1e build. ‘table in he heat- | reason, lable for thought of ext ad, how- ut that d mean ularly in se of its cided to rmation rent in ils thea »mbered ad told his new but he d_ that was to rooms garage, insula beyont ApRIL, 1929 / as a seventeen-room house. - ee later, when he questioned his friend, it appeared that insulation had been an afterthought in the seven- n-room house, so thattherewas a chance for actual comparison of costs. That is, the house had been planned originally without insulation, just the usual stud wall construction, with sheathing, build- per, and siding on the outside, and Jath and plaster on the inside; and con- struction prices had _ been obtained on this basis. Later, when insulating ma- terial was added, new prices were obtained and the difference showed that with insu- Jation the cost was approximately two percent more than the first figures. UT for two winters the owner of the B new house had checked his coal bills with those for another house about the same size—uninsulated. His bills each winter were less than those for the un- insulated house and so he figured that the difference represented his approximate annual saving. This saving would pay for the extra cost of his insulation in six years —leaving the insulation in the house as clear profit after that time. But before this saving on fuel started another saving was made—much to the surprise of the owner. When the insula- tion was added to the walls the heating engineer who refigured the radiation and the heating plant explained that it is not somuchthesize of a room which determines the size and number of radiators as the amount of heat that would be lost through the doors, windows, and wall surfaces. He had figured on the size of the room, the walls exposed to the outer air, the size and position of windows and doors, and perhaps what is the most important fac- tor—the type of wall construction. With these walls insulated the refiguring dis- closed that the radiators in almost every room could be reduced a little in size. The total reduction made it possible to use a much smaller boiler than had been speci- fied originally. The result was an im- mediate saving which offset a portion of the extra cost of insulation, without re- gard to the annual saving on fuel. . BREED’S client was “sold” on the idea of using insulation in his cottage at Riverside, but the question now came as to what kind he would use and just POPULAR SCIENCE MONTHLY used more or less like sheets of lumber. It was found that the raw material used in these different products is usually hairfelt, mineral wool, felt, or some kind of vegetable fiber. Within each is a tremen- dous number of small particles inclosing small—and, in some cases, minute—air spaces. This is in accordance with the well-known_principle that air is the best nonconductor of heat, provided it is “dead” air—air so confined that it can not easily circulate. Tests by the United States Bureau of Standards, by univer- sities, and by private This attractive front entrance bespeaks the comfort assured within through use of insulating materials. laboratories show that these various commercial insulating products are much alike in their heat-resisting value. Any one of them is about equal, in resisting the passage of heat, to an eight-inch brick wall or a 11-inch pine board. The owner of the Riverside cottage en- countered a man who had insulated an old house with the loose material. At a nominal cost it had been stuffed into the walls without much tearing up of the old work. While not all the spaces in the walls were filled, it had been sufficient to reduce his coal bills appreciably. In the where he should use it. He found a variety of insulating materials of widely differing types available. With his archi- tect he studied these prod- V-JOINT AND OVERLAP ucts in an effort to-de- termine for himself where they differed one from the other. The first considered was insulating material held between sheets of a A TH AND J 2°x4 INSULATING INSULATING MATERIAL LBLASTER STUDS QUILTING WOOD LATH Fig.3 Fig.4 Eig. 2 SIDING OR "7 SHEATHING — ATH STRIPS BUILDING \HOLDING QUILTING {PAPER i " tough paper and quilt- ed in place. Next there was the loose form in which wool or fiber is placed as a packing be- tween the studs or rafters. And then there were boards with the insulat- QUILTED —s SHEATHING, BUILDING PAPER, - SIDING OR SHINGLES ) MN =m KM HK INSULATING ° QUILTING Fig.6 —_ —_-____—_—— ing material compressed into products which can be These diagrams illustrate half a dozen methods of applying various roof and wall insulating materials to assure adequate protection. 75 case of the new house this kind of ma- terial could be put between the studs as the sheathing was being applied, as shown in Fig. 1 on this page, giving an even filling throughout the exterior walls. There would always be the possibility that it might settle and pack down as time went on, leaving certain unprotected spots, but the manufacturers maintained that the roughness of the wood construction would hold it in place satisfactorily. If the quilting, which stands well in the lists of efficiency, were to be used, there would be various ways of applying it. It could be put between the studs, against the inside of the sheathing, and nailed in the corners against the studs, or it could be used in the more usual way, over the inside of the studs, with the lathing nailed over it ready for plastering. Or it could be run zig-zag the way many builders and architects recom- mend; that is, starting on the face of a stud it would run to the sheathing midway between two studs, be fastened there with a lath strip, and then run back to the face of the next stud. A variation that uses a little less material is to nail it to the inside face of one stud and then to the outside face of the next and back to the inside again. The theory is that this zig-zagging breaks up the air spaces more and adds to the efficiency as insulation. The various methods are shown in Figs. 3, 4, 5, and 6 on this page. UT the advantages of using one of the boardlike materials seemed to Mr. Breed’s client to out- weigh in his case the slight differ- ences in efficiency which the other kinds offered. In the first place, because of the rigidity and strength of these boards, they can be used in place of wood boards on the outside of the studs, eliminating both the sheathing and the building paper which are generally used. In this; way insulating board is simply substituted for the sheathing and, though the cost is increased, real insulation is ob- tained. Of course, the increased cost is reduced somewhat by the saving in sheathing and building paper. Another way of insulating with the boards is to apply them to the inside of the studs, where the lathing would or- dinarily be put. While laths could then still be put on top of this it would be an unnecessary expense, as the plaster can be applied directly to the boards. Most insulating boards have such a surface that the plaster adheres to it perfectly and forms an unusually strong bond. ITH some makes of insulating boards even the plastering may be dispensed with and wall paper applied directly to the surface of the boards. When this is done the joints between the boards must be carefully filled with a cement paste—usually supplied by the manufacturers—and then rubbed smooth to keep from showing! through the paper. An important improvement for using these insulating boards on the inside and as a “base” for plastering has been developed recently. They may now be obtained in comparatively small pieces, about eighteen inches wide and four feet long, instead of (Continued on page 172)

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76 POPULAR SCIENCE MONTHLY APRIL, 1999 The New Household Inventions Rugs can’t slide or pull un- der vacuum cleaners when the latest antiskid buttons anchor them in place. Half of a fastener is attached to the floor at each corner. The other half, sewed to the rug, is quickly snapped into it. A timing mechanism won’t let you burn bread in this new electric toaster, When the toast is just right the cur. rent snaps off and the two doors open to deliver two gclden-brown slices, Clamped to faucets with Y-shaped arms, this new washer cleans your dishes with water swirled around by anelectric pump. With this combined ice pick and bot- tle opener you can crack ice or uncork a bottle in a jiffy, thus saving time. By placing the washer on a rolling stand you can wheel your dishes to and fro. id on ¥ Ths a $ ‘. a — ao fava Se You’ll shed no tears when you chop or slice onions with this glass-inclosed plunger. Put the vegetable on a wooden base, cover it, give the protruding handle afew strokes, and presto! the job is done “without a tear in an onion.” In addition to breaking up food particles to pass down the drain pipe, the washer’s electric motor will run a cream-whipper, an egg-beater, or a small drill used on household jobs. A rotating a set screw, may be easily moved from place brush also will remove cooked food adhering to to place on this can opener to help you in pots and pans. To cleanse dishes add washing cutting the covers of any tin containers. powder and a strong hot spray does the rest. Here’s a new improvement on an old house- hold tool! An adjustable blade, held tight by

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PRIL, 1999 Ns let you toaster, the cur. TS Open 1 slices, incork ass or ng to ng st. Apnat, 1929 POPULAR SCIENCE MONTHLY 77 Mechanical Novelties in Wide Variety Offer Greater Convenience and Economy in the Home + ' Wy ~ ~ cont ta Sometiday Yeu Aud See Mi Insurance against accidentally opening the cocks of a gas range is provided by the simple lock-tight metal strip which P. Albanese, of Passaic, N. J., the inventor, is exhibiting. His device can be used on gas stoves with any number of burners. Your safety razor will never be out of place if it is kept on this con- venient little china stand, which has a compartment tor new blades and a receptacle into which the discarded ones may be dropped. Here’s a genuine “cooking cabinet’’ for summer as well as winter use. Inch-thick insulation prevents its heat from warming the kitchen. When its cover is shut a small simmer burner will keep food warm for hours. An “‘elevator’’ saves stooping to lift a roast, as shown above. Cooking Odors escape up the chimney and the Stove cannot be closed until every gas cock is shut. When closed, as at right, the cabinet resembles a percel-post box. Protected from dust and rust, your electric iron is tucked away in this built-in wall closet, which also serves as a rest for the iron when in use. Asbestos lining and a ventilated door allow safe storage of iron while hot. Brooms, mops, and household tools with handles can be con- veniently kept in wall brackets like the one at the right. Curved nonskid holders grip the handles by spring tension as they are pushed into place. A lift re- moves the article when needed. For girls who prefer to launder their own fragile silk stockings and flimsy lingerie this little metal washboard is just the thing. Its curved hardle fits the back of the hand that grips it, when placed in a basin, and its corru- gations are declared to be harmless to delicate fabrics. -—

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By H. J. Roskxyu ITH the exception of dressing tables, most small, individual pieces of modernis- tic furniture seem to have been designed mainly for masculine use and enjoyment. In the ac- companying illustrations, how- ever, is shown a piece of furni- ture in the modern taste de- signed exclusively for the use of the lady of the house. At first glance this sewing table or cabinet may seem to be rather complicated, but it is not. If each part of the table is examined, it will be found that the construction has been simplified in such a manner as to require only the simpler tool processes. When the table is to be stained in a dark color and var- nished or lacquered, gumwood, which is inexpensive and has a beautiful grain, is an excellent wood to use, unless the more costly walnut or mahogany is preferred. If the piece is to be finished with colored brushing lacquer or enamel, whitewood or some other close-grained, easily-worked wood will serve. eo POPULAR SCIENCE

83 ——+_ f te Roo WieciSetntumansecessaasl Py “SIIIHINGES----* 7) il HALF PLAN i — N 3 en, _i HALF SECTION : .— - B71 +) ms Cr | : a F S 51 || 0 re — TRAY FITTING : i as off? WITHIN BOX. ‘at }— 18° 1 : ——H ~ . s . ae CORNERS IN y ‘O eT eh IK W 4) IN VERTICAL SECTION Y y Sssossssssocef Penn i 6’ i Cc © | iH N | HH - xa) i BOLT : F 50 _T K t = BOX_IN_ PROCESS — arte —t | —_ , alee =a D<-a }-——9"5Q_-|= fe! | pe! ig by - ry st N = For -+——11"sa-——-| “#0 | anne? | +——10!'sq—+| “be 7 Lk { — —j]— P + j-_— 1°sa——-] * = DETAILS OF BASE

PLAN OF BASE

| a aN aN METHOD OF LAYING OUT OCTAGON FROM A SQUARE terials, yy

How the table is constructed. For an itemized list of ma- turn to page 119. In constructing the upper or boxlike section, the pr cedure is to make an open bor and screw the sides and bottom securely together. Next, four narrow cleats are glued to the outside of this box, flush with its upper edges. Brads, which are not driven all the way in, can be used to hold them in place until the glue sets; then the brads may be withdrawn. The slats that transform this plain box into a cabinet of dis tinction are prepared and ap plied in the following manner: Eight strips 3¢ in. thick, four of which are % in. wide and four 1 in. wide, are cut to length in a miter box. Theit edges are chamfered slightly. These slats are glued in place at the corners as shown in the isometric sketch. When the glue has dried, these corners, including the horizontal cleats, are planed round, after which the remaining slats, which are 3 in. thick and 1 in. wide, are glued in place. The column is made of two pieces in which a groove for the bolt must be cut before gluing. It would be better for the amateur of limited (Continued on page 119)

Ap!

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rle le upper he pro. pen bor 1 bottom xt, four d to the ish with s, which way in, them in ts; then drawn. orm this t of dis. und ap- nanner: ck, four de and cut to Their lightly. n place in the on the orners, cleats, which ch are le, are of two or the ‘luing. r the mited m Apait, 1929 POPULAR SCIENCE MONTHLY 79 Who Can Match This Shop? A. J. Stuhler, Who Likes to Make Things at Home, Pursues His Hobby with an Assortment of 1,238 Individual Tools and Machines HAT kind of home work- shop most of us have pic- tured only in our day- dreaming A. J. Stuhler, of Monticello, Iowa, actually owns. Contained in two rooms, the shop includes 1,238 individual tools and machines. Each machine has an individual motor, and there are fourteen 4-H.P., one 4-H.P., and one 14-H.P. motors. The man who has assembled, set up, and even built part of this extraordinary assortment of tools and machinery is a member of a firm.engaged in general merchan- Mic % i 4: es ; eal ee ane dey | —- ‘ i aa i! +. m.. - i} Fig. 1. Mr. Stuhler, who : owns one of the most 6 complete home work- , shops in the world, work- I ing at one of his. lathes. Note the combination woodworking machine. Fig. 2. Bench with electrical and chemi- cal equipment, torches, and air brushes. dising and is himself occupied in managing the company’s grocery store. In Fig. 1 Mr. Stuhler is seen working at one of his lathes. He has an inclosed tool cabinet within easy reach, and at his left is a dou- ble emery wheel stand. At the extreme right of the illustration is a motorized woodworking machine consisting of a circular saw, planer, sander, buffer, grinder, and drill. Pasnars your own home work- shop, while it may not be nearly as large or complete as the shop of Mr. Stuhler, has in it some outstanding features of equipment or arrangement which would interest the readers of POPULAR SCIENCE MONTHLY. If so, send photographs of it with a brief de- scription to theHomeWorkshopEditor. Payment will be made for all photo- graphs and suggestions that are con- sidered suitable for publication. Flood and spot lights aid in doing close work, and a traveling flood light on an overhead cable can be adjusted to disperse any shadows. Hardware supplies, an electrical kit for experiments, and a home- made test board supplied with D.C. and A.C. current are shown in Fig.:2. Here Mr. Stuhler also keeps his acetylene lead-burning and oxyacetylene torches, which are supplied from a tank on a ledge above the bench and with air from a homemade compressor, a part of which is visible at the extreme left. A cabinet at the right A Fig. 3. General workbench with con- veniently arranged tools and machines. end of the bench contains a fairly complete miniature chemical lab- oratory for experimental work and for use in conjunction with an electroplating outfit. Under the bench are several air brushes for spraying lacquer, and on a turn- table at the extreme right is a motor-driven sprayer. The upper part of the cabinet at the right con- tains a complete set of alcohol and gasoline (Continued on page 128) Fig. 4. Woodworking bench with a combination machine and a wood- turning lathe. In the background is a heavy jig saw and a speed lathe. Fig. 5. Rear of the bench shown in Fig. 4. Note the small band saw. In this room, but not shown, are also a shaper for wood and a jointer

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Turning AKING small boxes is one of the most interesting and fascinating types of work that can be done on a wood-turning lathe, for the possibilities in the choice of size and de- sign are almost without limit. The cover of the powder box, Fig. 1, is turned from a piece of wood at least 1 in. more in diameter than the finished dimen- sions call for. This piece of wood is secure- ly screwed to a faceplate or screw chuck, after which it is turned to diameter and leveled. It is best to turn the inside of the cover first, and then to cut the recess which fits into the lower part of the box. Use a template for this work. When the outside of the cover has been turned, it is cut off with a parting tool or skew chisel #s near to the line as possible. Hold the parting tool with the right hand and grasp the lid with the left hand the moment it is POPULAR SCIENCE MONTHLY Fancy if Boxes and Bowls jf By HERMAN HJORTH ae: cut away from the waste. The lower part of the box is turned in the same man- ner as one of the trays illustrated in last month’s article (Fig. 4, page 81). It is cut to‘approximate size, glued to waste stock (Fig. 2), and turned in the usual manner. Particular care must be taken to turn tiie diameter of the opening so that the cover will fit snugly and yet not so tightly that it must be forced in place. The size of the opening should be tried while it is being turned by fitting the cover to it. The lower part of the box may be used as a chuck for the lid, which must be smoothed off and sanded at the central point where it was cut with the parting tool. The whole box is now stained and polished, after which its lower part is re- moved from the waste stock by driving a APRIL, 199 - Attractive wooden fruit dishes and nut bowls can be made easily by the amateur turner sharp chisel into the latter 1% in. behing the glued joint. A recess may be cut the underside of the box by chucking itp the manner shown in Fig. 7 of the artic), published in the March issue. The jewel box, Fig. 3, is turned in exact, ly the same manner as the powder bor, but as it is inlaid, the stock must be pre. pared in a different way. The lines of inlay are produced by gluing different og. ored woods together in layers. The lowes layer, for example, may be a dark-colored piece of wood, such as black walnut o imitation ebony, 3% in. in thickness. The next layer is a light-colored wood, such as maple or birch, 4% in. thick. This is fol. lowed by a dark layer 1% in. in thickness, and this again by (Continued on page 117) cal Pelee t 3 B a, ~ GLUED TO WASTE STOC TURNING LID OF JEWEL a) 4 POWDER BOX F/G./ LOWER PART OF BOX GLUED To WASTE. STOCK WITH LAYER OF PAPER BETWEEN BOX €& STOCK ual 9 Four designs especially prepared for readers of Poputar Scrence Monrtu_y. The proportions and contours have been given careful study and in many FRUIT DISH (G+ a ee FIG.7 J+ —- SET mshi | subtle ways differ from ordinary turnings. copy one or more of these before attempting to make designs of his own. hth It will pay the beginner to Apri con eac! of t to |

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Abu, Igy at, Ba a Re of Ess e% a eee aad SS ApRIC 1929 POPULAR SCIENCE MONTHLY 81 Hammering Out Metal Trays Fig. 1. How a rectangular tray is formed in the vise with the aid of a homemade tool. MALL card, ash, and pen trays (Fig. 2) are easy for the beginner in decorative metal working to make. They form useful and acceptable gifts and, when well shaped and neatly finished, can be sold at a profit if a local market can be found for them. Round trays in the smaller sizes are usually hammered from copper or brass, gage No. 20 or 22. In this process turned wooden molds are used as shown in Fig. 3. Naturally, a separate mold must be pre- pared for each size. A disk of well-annealed metal is cen- tered over the depression in the mold and small nails are driven part way into the wood and bent slightly inward to hold the edge down as shown in Figs. 3 and 4. The metal is driven into the depression by hammering around and around in one line just inside the edge with the rounded end of an embossing hammer. The ham- mering, which must be done only at the edge of the depression, stretches the metal until it reaches the bottom of the bowl. To aid in centering the disks, several concentric lines are turned in the top of each mold. It is easy to make a number of trays exactly alike, but do not attempt to make trays more than 8 or 10 in. in Fig. 3. Using an embossing hammer to drive the sheet copper into a turned mold of hardwood. You Will Be Surprised How Easy It Is to Make and Emboss Artistic Looking Receptacles for Ashes, Cards, or Pens By EDWARD THATCHER Fig. 2. Embossing the rim of a hexagonal tray with a blunt punch. The work is supported on the end grain of a block of wood. At the right—three trays. In the course of stretching the metal to the bottom of the de- pression, it will be necessary, of course, to remove the tray at least three times to anneal it. The edges of the outside of the tray will have a tendency to buckle up between the nails. Gently ham- mer down these places at once. Also straighten out the edges each time the work is annealed, and true up the whole piece before placing it back in the mold. Properly done, this method leaves no hammer marks. If you wish to hammer-mark the metal, place the disk on a flat steel anvil and mark it before setting it on the mold. Trays made in this way may be polished and colored as you wish or by any of the methods suggested in previous articles of this series. Another method used for making square, triangular, or six- and eight- diameter or of thick metal. Beech or maple is an excellent wood for the molds; it should be from 1% to 2 in. thick. To prepare a disk of metal for a tray, scribe a circle of the proper diameter and first cut a square containing the circle. Cut off the corners of the square close to the circle and then trim away the remain- ing metal, making a continuous cut with the shears. Never try to cut out a cir- cular piece directly from a large piece of metal. HE metal is annealed by heating it to a dull red and quenching it in a “pickle” made of ten parts water and one part of either nitric, sulphuric, or muriatic acid. In making the pickle, add the acid slowly to thc water. Never pour water into acid; it is highly dangerous. Rinse the work in clean water and allow it to dry. To fasten the disk over the mold, use at least eight small nails. For the actual hammering you cannot use a common ball peen hammer; you must either buy or make one or have a blacksmith forge one for you (see the article Tools for Metal Working, June, 1928, issue, page 104). sided trays is illustrated in Fig. 1. The vise jaws are protected with false jaws. These are made of sheet copper about 2 in. wide and as long as the vise jaws. They protect the trays from being scored by the jaws. A wooden tool made as shown in Fig. 5 is used to drive down the metal as in- dicated. The tool may be made from a length of broom handle or a large maple dowel stick. Copper or brass of gage No. 20 should be used. For a rectangular tray, cut the metal slightly larger than the finished size, because the outer ends will be drawn in slightly. Enough metal should be left to allow the edges to be squared up later. After annealing and pickling the metal, draw the inner rectangle with a pencil, not a scriber. With the pencil line even with the top of the vise jaws, clamp the metal as tightly as possible. Drive the wooden tool gently along the top of the jaws, making at first merely a slight depression. If the tray is longer than the vise jaws, loosen up the work and reclamp it as you work along. Do all four sides in the same way,trying (Continued on page 126)

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82 POPULAR SCIENCE MONTHLY SuMNER Biossom, Editor Raymonp J. Brown, Managing Editor Artaur WaAKELING, Home Workshop Editor Aurrep P. Lane, Technical Editor Epcar C. WHEELER, Associate Editor IsRAEL Doskow, Art Editor Published Monthly by Popular Science Publishing Company, Inc., 250 Fourth Avenue, New York City. Single Copies Twenty- five Cents. In the United States andIts Possessions and in Canada, $2.50 the Year. In All Other Countries, $3.00 the Year. Protecting Yankee Ingenuity T. STEBER, of Utica, N. Y., in a letter to PopuLar ScrencE MonrTxLy, criticizes the conduct of the U. S. Patent Office. He charges that instead of serving as ®an incentive to invention, for which it was intended, the Patent Office stifles initiative by dilatory methods. Complaints of this kind are frequent. The length of time taken to pass upon application is often criticized, as is the fact that the personnel of the Office sometimes seems to fail to keep abreast of trends in invention. It is only fair, however, to point out the difficulties under which the Patent Office labors. Inventions revolutionizing whole industries have been following one another in swift suc- cession. Each, in turn, breeds hundreds of other inventions. Radio and aviation are cases in point. The year 1927-28 saw 117,000 patent applications filed as against 86,028 in the pre- vious year. Nevertheless, improvement is urgently needed. We are the most inventive nation in the world. The whole structure of our present prosperity is built on what used to be called “‘ Yankee ingenuity.” It is difficult to name an industry that is not expanding as a result of the applications of inventive science. Readers who have suffered from delays of which Mr. Steber complains are urged to tell us of their experiences to the end that we may lay them before the proper authorities. Keeping a Step Ahead N R. McMAHON’S story of Wilbur and Orville Wright, now appearing in PopuLar Science MonrHucy, lays stress on the skepticism with which the airplane was received. In this connection it is interesting to recall that this magazine was the first to give credence to its invention. Our issue published in December, 1903, a few days before the first successful flight, said editorially: “The flying machine is no longer prob- lematical; it is simply a question of the time necessary to put things together.” That sentence was written at a time the Wrights were facing ridicule. And in our issue for March of 1904, Octave Chanute, whose part in the development of the airplane Mr. McMahon rs graphically portrays, wrote describing the first flight in etail. For more than half a century, writers for PopuLAR ScIENCE MonTHLy, unswayed by popular misconceptions, have been keeping up with, and just a bit ahead of, the march of progress. Every significant invention and discovery has been scrutinized, Aprn, 1929, analyzed, and evaluated in simple language for our readers, Today, as in the past, these men do more than repo facts. Month after month, on the basis of their know they look into the future and make remarkably prophecies of the wonders to come. Wherever men are doing new and useful things, there yo, will find writers for PopuLAR Science Monraty. 7 Why Not Make Use of Them? i’ SEEMS only the other day that Jack Binns, from the Republic, first used radio to send a distress call from sinking vessel. In this issue is told the story of the use of another scientific development in saving life at sea—the radi, compass. We marvel as we read the story of the rescue of th. crew of the Florida, Yet few of us stop to realize that after, we make comparatively only meager use of the available g of science at sea. For example, Robert H. Marriott, of the Federal } Commission, recently pointed out that although an elect cable could be laid in New York Harbor that would allow blindfolded helmsman to follow the channel, such a devics® not used. The practicability of the idea has been demon strated by the Navy. Using an echo to tell the depth of ocean is another navigational method that should be me widely used. Aviators are demonstrating what can be done by the inte ligent use of modern navigational methods. Something More to Worry About s AX time an otherwise obscure scientist desires to get | name in the papers he does a bit of calamity ho Sometimes he predicts a famine in oil or coal or wood, but most popular prediction is that the world is coming to an at some not distant date. a In the light of recent scientific revelations, these cala howlers are pikers. It now is possible to predict, if you want instantaneous annihilation—the end of everything for all of us! Light travels at an approximate speed of 186,000 miles 4 second. Recently, the astronomical observatory at Mount Wilson, Calif., observed a whole collection of stars in the form of a nebula traveling away from this earth at a speed of 2,500 miles a second. No scientific evidence is available to show that this or any higher speed is the ultimate limit. Assume for the moment that there are other stars, gigantic stars, traveling at even higher speeds, perhaps as fast as light itself, and traveling toward the earth instead of away from it. We couldn’t see the light from them until the stars themselves reached the earth. In other words, unseen by us, a blazing sun as large as our own may, at this very minute, be rushing at us out of the depths of space at a speed equal to or greater than that of light. So if you enjoy worrying about things, you ought to be able to get a real kick out of that gloomy prospect! But really there is no more scientific evidence to support such a theory than there is to support many of the possibilities pessimists like to point to. They Are Saying — “TPXALL buildings are a menace to health.’”’—Shirley W. Wynne, New York City Health Commissioner. “Of ten possibilities of danger in aviation, eight involve the take-off.” —Juan de la Cierva, inventor of the autogiro. “What do my 300 burns amount to compared with the thousands of patients that my work has saved!’’—Fernand Ducretet, French X-ray martyr. “When you are successful in pitting brain against bits of iron, metals, and crystals and making them do what you want them to do, that is all the reward you want.”—Prof. A. A. Michelson, famous American physicist. “‘Man’s two needs are a family doctor to safeguard his health and research to enlarge the doctor’s knowledge.” —Dr. Joseph C. Bloodgood, Johns Hopkins University Medical School. “A kangaroo is just an abortive attempt of Nature to make a safe pedestrian.” —Lord Dewar, English industrialist. “An average pine tree manufactures a broomstick a day and uses two barrels of water to help do it.”—Dr. D. T. Macdougal, Carnegie Institution biologist. ApRIL, SE

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iP Bee § HBAEEEE A * er erk ke +OPULAR SCIENCE MONTHLY TTI a 1A Fag hihi AN j f HM iri, 0 » (tt wuneaidl ee i is \aithleay tif i, | I i AHI YA Al \ fh \\ nn i i 4 | / Wi i) yy 0 i jews tl yi wt (WM i\\ \\ nY/// Yy A VW N77) WAad/3 ‘ Nes, ‘\Z fh / = igi g s ==. 3 = — Va V uy Y f ¥ Smoking cauldron and smoking pig! The attend- ance of careful men; the sledge blows of men of brawn. All these caught by the master’s brush and preserved for posterity on the walls of Norton Hall at Worcester in Massachusetts. H=«: and the bright light of the electric arc! All who view the scene may know how Bauxite clay from the mines of Arkansas, by energy taken from the waters of Niagara, is fused in the electric furnace and becomes the hard, tough material known in industry as the abrasive trade-marked “Alundum.” By day and by night, while we wake or sleep, these fiery furnaces burn on, continually bringing forth the abrasive which is to serve mankind in a multitude of ways. From the abrasive, trade-marked “Alundum,” are fabricated the grinding wheels employed in _all- important machinery operations in metal-working plants and many others. By the aid of grinding wheels there are produced countless machines of production and of tfansportation, and by the grinding wheel they are brought to mechanical perfection. Mural by Arthur Covey. Wood block engraving by Howard McCormick For the great paper industry, manufactured pulpstones reduce logs at tremendous speed into fine, even-grained pulp. For the broad and ever increasingly important field of chemistry, laboratory ware made of this abrasive, capable of withstanding terrific heat, performs an invaluable service. For the architect and the builder Norton floors, non-slip and remarkably durable, supply a need in modern building construction. The basic material of Norton floors is this electric furnace abrasive. For great cities employing the activated sludge sewage disposal systems and industries where filtering opera- tions through plates are required this material serves in the form of Norton porous plates. In the beginning, manufactured abrasives supplanted natural quarried stones for sharpening and snagging. Today their use has been extended through the agency of the grinding machine to a high place of importance in the machine age in which we live and many are the by-products which time has proved definitely valuable to the progress of the world. NORTON COMPANY, WORCESTER, MASS.

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If Your Headlights Went Out-= And You Were Speeding Forty Miles an Hour, What Would You Do? Gus Explains the First Rules for Safe Driving By MARTIN BUNN 7 E’D better step on it, Gus; the wife’ll have the eats wait- ing by now,” Joe Clark urged as he locked the door of the Model Garage and hastily climbed in beside his partner. “Huh!” snorted Gus Wilson. “You don’t have to tell a hungry old bachelor to hurry when there’s home-cooked fod- der in sight!” The veteran auto mechanic snapped on his lights, for it had become quite dark, and swung out onto the concrete road. The gears whined in second while the car gathered headway and then, as Gus noiselessly shifted into high, a nee whizzed past them at high speed “Another guy late at mealtime may- be,” Gus suggested. “He sure is in one great big hurry.” The sedan rapidly drew away from Gus’s car and the tail-light finally winked ad it reached a distant bend in the road. ““Something’s funny or else I’m losing ‘my sense of distance,” muttered Gus. ““How did he get around that bend so quick? Didn’t seem to me he’d even reached it.” “G’wan!” Joe grinned. “Of course he did. Where else could the lights go?” But when they reached the bend, Gus’s headlights glared on a man standing in the road and waving his arms to attract their attention. The front end of the sedan was jammed through the fence on the outside of the pavement. ““What happened?” asked Gus as he pulled up. “Lights went out all of a sudden,” explained the stranded one. “I reached over to see if the switch had snapped off, and the next thing I knew I hit the fence.” ‘US got out a flashlight and rapidly J inspected the wiring. “‘Here’s the trouble,” he grunted. “Wire broke off right at the switch.”” He reconnected it and the lights came on at once. Luckily nothing vital appeared to be broken, so he backed the car onto the road again. “Better bring it down to the Model Garage tomorrow and [ll make sure everything is all right and take the wrinkles out of that mudguard.” The accident victim muttered some- thing unintelligible and immediately drove off. “And not so much as a ‘thank you,’” Joe whistled in astonishment. “Don’t blame him,” Gus smiled. “‘He’s just scared stiff. Kind of ‘accident shocked.’” POPULAR SCIENCE MONTHLY Gus’s suggestion hed régistered, how- ever, for the next day the man appeared at the Model Garage. “My name’s Considine,” he began, “and I want to thank you for what you did for me last night. That was my first accident and it sure did scare the day- lights out of me. Spoiled my self-con- fidence, too. I’m nervous as a cat now.” ON’T let it get your goat,” Gus smiled as he started ironing the dents out of the mudguard. “It’s no disgrace to be a beginner so long as you don’t get to think you know it all. Trou- ble is, there’s a lot to driving besides shifting gears and turning the wheel. And most people are lucky if they find that out before they get into a serious crash.” Considine smiled ruefully. “‘ Yesterday I'd have said that was a lot of bunk. Now 1 know better. What would you have done if you'd been in my place last night?” “*That’s easy,” replied Gus. “My foot would have been pushing a hole in the floor board with the brake pedal the instant after the lights went out, and Id have watched the sky line along the trees to keep me on the road till I stopped. “But,” added Gus, “if I'd been you I wouldn't have been driving so fast. You oughtn’t to drive fast until you've had more road experience. Lots of things can happen when you are hitting it up that wouldn’t mean anything if you were going slower. A blow-out, for instance, means nothing if you’re ambling along, but it takes a good man to keep a car on the road if a tire lets go at high speed.” ““How fast ought I to drive, then?” Considine inquired. Apri, 1995 Gus’s headlights glared on a may in the road, waving his arms. His car had crashed through a fence, “Well,” said Gus, “‘ when I first tackled driving a gasoline buggy, back in the days when a progressive gear shift was the latest thing and cars didn’t have any windshields, the man I was working for took me out for my first lesson. We were roaring along at thirty miles an hour— dangerous speed in those days—when all of a sudden the boss jammed on the brakes and I nearly dove over the hood, seeing as how there was no windshield to stop me. ‘There,’ said he, after Id crawled back into the seat, ‘I just wanted to show you the first principle of safe driving, and that is to know how to stop quick. Never drive so fast that you can’t stop within the clear space you can see ahead.’ HAT principle is just as good now as it ever was, and it’s a kind of automatic rule, because while you're 4 beginner you won't be able to make as quick stops as you will after you get s0 that your foot snaps onto the brake pedal without having to stop and think about it. Whenever there was any doubt in my mind whether I was going too fast I used to imagine another car darting out of a side road and see how quick I could stop —but you want to be sure there's no car behind you when you try it!” “I thought four-wheel brakes made fast driving safe,’ said Considine. “*Safer—not safe,”’ Gus stated. “‘ Noth- ing can make driving safe if you're going too fast. Of course, other things being equal, you can hit it up a bit more if you have four-wheel brakes. “And while we’ ‘re talking about speed,” Gus continued, “‘remember that a safe speed on dry roads is a lot too fast when the going is (Continued on page 174)

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POPULAR SCIENCE MONTHLY "85 ‘li esi: neat at PE.» 20 On @ man ; arms. His t h a fence, tackled : a sd | in the iw! | ALRRFRED H. GREBE ave any ki —— President, A. H. GREBE & CO., Inc., says: hour— vhen all oo “In replacing worn vacuum tubes we Look for this mark on every Radiotron OT Pras mnt wanted : strongly advise all owners of Grebe Receiv- : at you P| ing sets to use RCA Radiotrons. Our labo- you Can ‘ ratory tests have proved that they give an | the best results with Grebe instruments.” ake as f ; get 30 e pedal j about A / inmy | | | I used ; i it of a ld stop f Used for laboratory tests and for initial equipment and strongly recommended no car for replacement by all makers of quality radio sets, RCA Radiotrons will improve the reception of your set. When you need new tubes do not put them in with old ones. Put a new RCA Radiotron in every socket and notice the difference in performance. RCA RADIO TRON RADIO CORPORATION OF AMERICA «+ New York ~ Chicago ~ Atlanta ~ Dallas ~ San Francisco Et a made wt cae eR 2 Noth- - going being if you eed,” a safe when ye 174) © This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE 9F STANDARDS. See page 8.

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Rarely is a house built with enough closets, but any man can make fittings to increase their capacity. OU can put more of the closet space in your home to practical use by building in additional shelves, coat rails, and compartments and by adding hooks, rods, and hangers. Figure 1 shows a simple and practical way to place shelves at the back or end of a closet. A post, 3 by 114 in. and of a length to reach from the top edge of the baseboard to the ceiling, is placed at each side of the closet as shown at A. Posts B of similar size, about 1 ft. long, are set in the corners at the back between the shelves, which may be as wide as desired and as long as the width of the closet. The shelves are held in place by nailing through the long post, as shown at C. POPULAR SCIENCE MONTHLY Simply by Adding This places the first shelf about 18 in. from the floor. The front post may be toenailed to the wall, and the baseboard and the cor- ner posts facenailed. By building the shelving to the ceiling, mate- rials that are not frequently used may be stored on the upper shelves, and thus space is used that otherwise would be idle. Another way to increase the working space in a closet is to build two coat or cloak rails as indicated in Fig. 6. In addi- tion to the usual rail at 5 ft. 8 in. from the floor, an additional rail is placed at 4 ft. 6 in. from the floor. This is especially helpful for children’s use. The hooks on the lower rail are placed halfway between those on the upper rail. Figure 6 also shows a shelf placed on the top of the upper rail for hats and mittens; and resting on the baseboard is a shelf for shoes. The latter should be 11 or 12 in. wide. It is well to finish the shelf with spar varnish. It need not be More Closet Space How to Gain Room for Storing Clothes Hooks, Hangers, and Various Fixtures ~ By L. M. ROEHL APRIL, 1999 Shelves, Coat Rails, nailed to the baseboard; thy may be taken out for clean) A method of keeping ru} and mittens in a closet is jp cated in Fig. 2. Three shely are placed 6 in. apart, and on them y tions are placed so as to make co ments 6 in. square. The case is bul placed on the baseboard at the back end of the closet. It should be noted th the shelves are 10 in. wide and that th grain of the wood in the partitions rujy vertically. By this construction, piecs 6 in. long may be cut from a 10-in. ee for the partitions; in like manner typ pieces 1334 in. long may be cut for the ends if the wood is % in. thick. A simple and satisfactory way of hang. ing a rod for holding coat hangers fo coats and dresses is illustrated in Fig, 7, A %%- or 4%-in. iron or brass rod, ora in. piece of hardwood doweling, is placed across the closet at about 18 in. from th rear end. One end of the rod is placed ina hole in the coat rail as shown at A; th other end is held (Continued on page 185) POST IN CORNER "Xx 1¥2" X12" OR OTHER SPACE AS DESIRED TO CEILING a NAIL fr’ Cc ~/") P= = FIG. 1 oe Y2'x7e%4 "SCREW TO DOOR RAILS eae ~/ZDOWELS, 24”LONG FIG. 3 - _ : COAT RAIL 5-6" - YIFROM FLOOR CHILDRENS COAT RAIE 2° ]4-6" FROM FLOOR FIG. 2 FIG. 5 LEFT SIDE WALL == Ez SIZZLA 7 Yeron A * B:: 4X1 X4 BLOCK *." > , aie et laa aaa aS aan ae =—END WALL’: = Zz Seven ways to increase the capacity and usefulness of the ordinary clothes closet with shelving, racks, and extra hooks. Mr. Roehl, who offers these suggestions, is an assistant professor in the Department of Rural Engineer- ing, Cornell University, and is the author of ‘‘Household Carpentry.”’

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POPULAR SCIENCE MONTHLY 89 ApRIL, 1929 What a cigarette meant there Down from a starless sky . . . and after hours of utter strain, a moment of utter relax- ation. Safety after peril ... rest after struggle . . . companionship after lonely vigil . . . no wonder the solace of a friendly cigarette has a place of its own in men’s hearts, as What a cigarette means here Up from the sun-drenched earth— drowsily nour- ished under smiling skies, the tender leavesof tobaccoripen into gold or bronze. From what soil and rain and summer sun prepare, we select the prize lots. Aroma and fragrance from Turkey; from old Virginia and the Carolinas, rare mild- ness; mellow “body” from Kentucky. We “age” it and blend it .. . and from earth’s choicest tobaccos we give you Chesterfield. And about six million smokers tell us it’s more than worth all the trouble we take! Harvesting a fine stand of “bright” tobacco and hauling by sledge to the curing barn. ~... and pet THEY SATISFY

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POPULAR SCIENCE MONTHLY APRIL, 1999 Fix It Yourself with These Handy Hints for Motorists How to Keep Your Windshield Wiper Working, Build a Nest for Tools, Grind Valves an Easy Way, or Rig a Siphon HE average windshield wiper goes bad long before it is worn out. Constant contact with the surface of the glass puts a kink in the rub- ber edge so that it will not bend back and forth to clean the glass as it should. Fig. 1, below, shows how to avoid this deterio- ration. Take a small piece of sheet metal and bend it into a triangular shape. Then cut or file small notches in the upper edges. When the windshield wiper is not Hinges support these seats at the front and feet are provided at the rear so that there is a space between the bottom of the seat and floor of the car. You can utilize this space for two handy tool pockets, as shown in Fig. 2. Each pocket should be fitted with a flap held tight either by rings and hooks or by snap fasteners. The arrangement of the tools and the- number of pockets will be governed by the space available. A Self-Starting Siphon | oe of sucking rubber hose tp start gasoline siphoning out of a tank, construct the neat siphon shown in F; 4. Bend a piece of brass or copper tubing into a U shape. To one end attach q rubber bulb like photographers use. Ty the other attach a piece of hose. The, drill a hole in the tube at the bend Insert the rubber tube in the tank and squeeze the bulb. Press your in use, the sheet metal piece is REMOVE slipped over the wip- TO USE I — Fig. 1 Small metal guard stops warping of rubber windshield wiper. finger tightly over the hole and release the bulb. Remove your finger and gasoline will flow from the hole in the pipe. The hole must be below the level >f the gasoline in the tank. bulb a handy siphon. er so that the hinge pin will rest in the notches and the rubber will be held away from contact with the glass. This will prevent the rubber from taking a permanent set. Convenient Tool Pockets r he coach type of auto body usually i has the front seats so they can tip forward to give access to the rear seats. BRASS RING AND HOOK Fig. 2. Handy tool pockets can be rigged with canvas flaps under coach-body seats that tilt up. Fig. 3. Cut off a plumber’s force cup to fit the valve head and you have a simple grinding device. Trick Valve-Grinding Tool N ORDINARY plumber’s force cup, such as is used for, clearing clogged drain pipes, can be fashioned into a useful valve-grinding tool. The lower part of the rubber cup is cut off so that the diameter of the remaining portion is smaller than the diameter of the head of the valve. Pressing the cup tightly against the valve will cause the rubber to adhere so the valve can be rotated and lifted from time to time, as shown in Fig. 3. - Ten Dollars for an Idea! R. L. Ogden, of Edgewater, Colo., wins this month’s $10'prize for his suggestion of a valve-grinding tool, as shown in Fig. 3. Each month POPULAR SCIENCE MONTHLY awards $10, in addition to regular space rates, for the best idea sent in for motorists. Other contributions used are paid for at the usual rates. Running-Board Tire Rack IGURE 5 shows a convenient and simple running-board tire holder that can be made from a block of wood, some strap iron, and five bolts. As shown, the arrangement is for a rim fitted with four lugs, but it will work with other numbers of hugs, if necessary. Make sure that the tire is held rigidly in place. HOLE SAME AS LUG HOLES SAME AS IN RUNNING BOARD Fig. 5. A wooden block, strap iron, and five bolts compose this running-board tire holder.

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PRIL, 1999 Ts hon hose to f a tank 1 in Fig T tubin attach ¢ use, To se, Then e bend, ank and SS your hole and —- your flow e. The level of OLINE L tack nt and er that |, some vn, the th four imbers e that Aprit, 1929 POPULAR SCIENCE MONTHLY We offer you 30 000 91 of the finest miles you ever drove: | year feel in every mile We announce the New Mobiloil—an oil so startling in its performance that the superlative statements we are ready to make about it are actually conservative. For example, when we say that with regular drain- ing and refilling, plus common-sense care, this New Mobiloil will keep the first-year feel in your new engine for at least 30,000 miles, the facts are that in a great many engines the New Mobiloil has kept the first-year feel for more than twice this distance. Repeated road and laboratory tests have proved that use of this New Mobiloil commonly assures from 10% to 30% more power than other oils generally sold for the same motor. the New in Under high speeds you will find, as our road tests have repeatedly shown, that this New Mobiloil stands up better and consumes more slowly than other oils . . . and it is an established engineering fact that the oil which lasts longest and stands up best at high speed also lubricates best at any speed. Try this New Mobiloil. It will help save your good engine from growing old before its time. Mobiloil— the World’s Quality Oil—is made by the Oldest and Largest Specialists in Lubrication. VACUUM OIL COMPANY Makers of high quality lubricants for all types of machinery obiloil

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Desine Up Your Photographs POPULAR SCIENCE MONTHLY An Expert's Method of Preparing Prints for Framing—How to Emboss the Mounts By Wa.TER E. Burton bs ENRY, I wish you would take this photograph of Mary Ellen down town and have it framed,”’ Mrs. Webster said to her husband as he started for the office. “Tl get a frame and put the picture in it myself. That will be cheaper,” replied. ‘‘Where’s the yardstick?” He measured the pic- ture and found it to be approximately 714 by 10 inches. “T'll get a frame two inches larger all around,” he remarked, as he jotted down the figures. “I like a picture mounted so as to have a white border around it.” That evening Henr framed the photo. e covered the entire back with paste, carefully cen- tered the picture on a piece of stiff white paper cut to fit the frame, let the paste dry for an hour, and then tacked the picture with its mounting in the frame. “The picture doesn’t look al- together satisfactory, does it?” Mrs. Webster diplomatically hinted a few days later. “I wonder why it is so wrinkled.” “It’s warping because of the paste,” Henry announced, after . carefully inspecting his master- piece of framing. “I guess I didn’t dosucha good job of it.” Henry WAS look- pe LARS pictures in an art store win- dow today and saw several that were placed in mh ing at some | a little panel in ~~.! the mount,’ Mes. Webster said. “Could you fix this one like that?”’ “T know what I'll do. I'll zo over and see Jack this evening. He belongs to a photographic club or some- thing, and knows all about mounting pictures for ex- hibitions and the like.” As Henry anticipated, Jack was glad to explain his methods. His first sugges- tion was that Henry use for the 8 by 10 in. print of Mary Ellen a mount about 12 by 16 in., the material for which could be obtained at almost any art or photographic store. “Be sure that it is fairly heavy so that it will not wrinkle easily,”’ Jack warned. ‘“‘And you must give con- siderable thought to the proper method of trimming your print.” “But I always hesitate to trim a picture because I am afraid of spoiling it,’ Henry objected. “You can remove that fear by cutting two L-shaped pieces of cardboard,”’ Jack as- sured him. “By laying them on a print so as to form an | adjustable rectangle, you can experiment to your heart’s content. When you have found the most attractive portion of the picture and have elimi- nated undesir- able details, How to Mount Photos If the print requires trimming, two L- shaped pieces of cardboard are laid over it as shown below and shifted until the best way to crop the picture has been found. The trimming is done with a safety razor blade or a_ knife as illustrated above. How to place the print on the mount is determined as shown by the diagram at the left. The mount itself is embossed with a buttonhook or other blunt instrument, as illustrated in the uppermost photo- graph of this group. The under‘ay is placed as indicated at the right. Mary Ellen’s portrait on embossed mount with a narrow band of underlay showing, blurred edges, parts out of focus, to large patches of sky or foreground, and the like, you can proceed to trim you print. Usually you will have no difficulty ip obtaining a picture that does not lean to one side if you line up one of the edges with a prominent horizontal or vertinal line in the picture, such as the edge of building or the horizon of a sea view. ‘‘When you actually begin trimming, do it carefully, so as to obtain perfectly clean- cut edges and square corners. An old razor blade is excellent for trimming, and it should be used with a steel ruler or one APRIL, 1999 that has a metal edge, An old magazine, a piece of glass or zine, or other flat surface makes a suitable trim- ming support. The corners of the picture can be made square with the aid of a draftsman’s ninety- degree triangle. Or, if you have a number of prints to frame, you can make a scale on each of the inside edges of the L-shaped masking pieces, and it will then be a simple matter to obtain 4 true rectangle.” He explained that a photograph or other picture should never be placed in the exact center of the mount; it ought to be arranged s0 that the border space on each side is of the same width and that at the bottom is wider than at the top. To determine the most suitable position of any sized print on almost any sized mount, frst trim the mount so that the corners are square. Then place the print in the upper left-hand corner, as shown by dotted lines in the diagram on this page. Now makea pencil dot at the two lowe: corners and the upper right, A, B, and C. With the ruler. find the (Continued on page 118) om Ins

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| mount howing, ICUS, too und, and rim your ficulty in t lean to he edges - vertical >dge ofa view. ming, do ‘ly clean- _An old ing, and Pr OF one tal edge, azine, % Or zine, - surface ble trim- t. The > picture > Square d of a ninety- le. Or, number frame, > a scale e inside -shaped es, and a simple btain a ed that should onter of nged so de is of bottom termine y sized it, fret ers are e upper ed lines make a ors and ith the age 118) Apri, 1929 C & L 32 jae the most popular blow-torches we have This 8 eee z is more expensive than the 158 because 'e for much harder use. It is designed for the who uses @ blow-torch in his daily business and poate’ not only excellent performance but rugged d to stand rough handling. 32 contains the most advanced, patented C&L blow-torch improvements. It also has a red handle with a gold stripe. Sure sign of ever it is mad satisfaction, ‘You're investing in better and longer performance when you buy a Clayton & Lambert © AN EXPANDED gas orifice makes a blow-torch a piece of junk. And it’s the easiest thing in the world to enlarge the orifice in an ordinary torch. But a No. 32 Clayton & Lambert blow-torch has an orifice that can’t be en- larged — no matter how carelessly or how tight you close the valve. It’s a patented Clayton & Lambert improvement—one reason why you get longer service when you buy a Clayton & Lambert. In addition to being non-spreading, the orifice will not clog. As you close down the valve the carbon cleans out automat- ically. The improved orifice is but one of many Clayton & Lambert advance- ments. Every bit of mechanism is de- signed to give you quicker, better action. Inside and out, a Clayton & Lambert is built for long, strenuous use. Where a QROTECTicy SAWS NG POPULAR SCIENCE MONTHLY C&L 158 This blow-torch is especially made and priced for the man who likes to do odd jobs around the house, or to tinker with mechanical things. It will last a lifetime if it is not abused. The usual retail price is about five dollars. Most hardware, electrical and automobile accessory stores have it—or can get it for you quickly. Look for the gold- banded, red handle. hard bump might occur, a Clayton & Lambert is rein- forced. Whereyer extra protection should be—you'll find it in Clayton & Lambert. As an example, all Clayton & Lamberts are made non-explosive by a patented method of building the fittings into the tank. The vaporizing chamber is another Clayton & Lambert fea- ture. Its special vein system gives you quicker heat—more heat—and cuts down your fuel bills. You can’t see these things which Clay- ton & Lambert have done to give you the blow-torch you want. They’re inside—in the “works,” the important part of a torch. But they’re there—along with numer- ous other refinements. They ac- count for superior performance and durability. And that’s why Clayton & Lamberts are the most popular torches in the world. You'll know a Clayton & Lambert by the red handle with a gold stripe. CLAYTON & LAMBERT MANUFACTURING Co., Detroit, Mich. © This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8.

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One Bene Designed for Home | Workshop Use, ItIs of Heavy-DutyType Yet Easy to Build By E. E. ERICSON and every man who does much household repair work needs a fairly large, rigid workbench. Wher- | yan es amateur woodworker ever there is room available—in the a basement, garage, or large attic— the bench illustrated will make its appeal to the worker because of its strength, durability, and simplicity of design and construction. A bill of lumber is the first con- cern of anyone who wishes to con- struct this bench. The wood can be obtained at any lumberyard. Hard {yellow) pine can be used throughout with the exception of the leg at the vise and the vise jaw, which should be made of maple or a similar hard- wood. The top also will be better if of hardwood, but the construction will be a little more difficult. For convenience two separate lists are given (on page 130): first, the lumber order as it may be turned over to the mill or lumberyard; second, a stock bill showing the actual widths and thick- nesses of planed lumber as it comes from the mill and the finished sizes to which the material must be cut by the worker himself. The pieces may vary slightly from the dimensions stated, but the variations will not materially affect the finished workbench. The following order of procedure is sug- gested: 1. Cut the four legs to the required length. (The length indicated in the drawing, 30 in., is a good, standard height.) Attach the vise-screw nut. 2. Cut the two upper cross rails for the ends to the length given. BET i | | A man-size bench of the carpenter’s type for the amateur mechanic who does much woodworking and repairing. POPULAR SCIENCE MONTHLY h That’s Big Knough penny box nails or common nails in each joint. Check for squareness with a steel square. 6. Glue and nail the piece of 13¢-in. maple on the face of the vise leg as shown in the drawing. This should not be cut to length at this time, but should be trimmed even with the surface of the top after the top is applied. 7. Cut the two aprons to the proper length (first checking the length of the pietes for the top). Cut away from one of them the part displaced by the piece of maple facing on the front leg previously mentioned; then glue and nail them in place. Use the square frequently while nailing up the frame. 8. Take the actual measurement for the stretcher or shelf that runs between the two lower cross rails. If desired, this can be made to overlap a little at each end for effect. This wide stretcher will serve as a shelf for tools and materials. 9. Cut out the place for the drawer on the front apron. This is best done by 8. Cut lower rails. 4. Hold all four i =----4 legs together with a - hand screw or other if clamp in such a way that their outer edges are exposed. With fe enn eo nd lpgeas elt ebege LSE pencil and square, 7 draw crosslines to in- dicate the location of ~ the cross rails. The upper rails act also as backs for the tool compartments. iy) J ou : o }+—_—_—_2-4"____+| }0° = 5, Now nail up the two ends for the bench, using glue in the joints for added . I rigidity, and not less J than three eight- Top, front, and end view of the bench, and a detail of the stationary vise jaw. STRETCHER v4 =o 6°. ° 313; APRIL, 1939 boring holes in two diagonal of the rectangle to be taken out starting the cuts with a compass keyhole saw. ” 10. Fit one of the 9-in. boards each side of this opening, = them also support the top at thes points. Before fastening boards, nail on them the slats which form supports for the drawer, 11. Fit the shelves in the ends, nailing them to the under edge of the cross rails or against these rails as may be determined by the width of the boards and the distance the aprons extend. 12. Joint (plane the edges) an4 glue up the two planks for the top, Use four }4-in. dowels for the joint, Care must be taken to mark accy. rately for the dowels; use a marking gage, knife, and square. 13. Trim the top to the length of the aprons and fasten it with 244 ip No. 12 flathead screws. First bor a \%-inch hole 4 in. deep to receive each screw; then drill a hole right through into which the screw thread will slip easily. Hold the top in place, drill 3¢-in. holes into the rails, drive the screws, and glue plugs into the 14-in. holes, 14. Cut the board for the bottom of the tool trough for length and also for width, if necessary. Nail this in place and nail on the strip along its outer edge. 15. Form the vise jaw to required shape, making it about 7 in. at the top and 41% in. at the bottom. Plane a beve on the outer edges of this, but do not at- tempt to finish the top end of it until after the vise screw and the follower have been fitted. 16. Clamp the vise jaw in place with the upper end protruding slightly above the top. Locate center of vise screw to coincide with the flanged nut center; bore a hole to allow screw to pass freely, and fasten collar. 17. Now tighten up the vise and bore a series of holes through both jaw and leg in one operation for the follower or “lock strip.”’ These holes should form a slot nearly the full size of the cross section of the follower, that is, 36 by 3 in. Then chisel out for a tig fit in the jaw anda sliding fit in the leg, 18. Bore a series of holes % in. in d- ameter through the follower in a zigzag pattern about 1 in zpart, as shown. 19. Glue and dowel the follower into the vise jaw, be- ing particular that it is put in square with the jaw. 20. Tighten up the vise, plane off the end of the jaw, and run 4 bevel on the front side of it. 21. Make the (Continued on page 130) DETAIL ‘OF CONST RUC iCN AT VISE sn 1s —_-—8--| ' TOOL ‘ COMPARTMENT : ire 8.8.) @ °° 2 (a, ss a °

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lace, drill 1€ Screws, oles, ottom of also for place and dge. O not at- ntil after ave been ace with ly above screw to ter; bore ely, and ind bore and leg or “‘lock a a slot ction of Then a 4 a the leg. 1 series . in di- gh the zigzag t 1 in mn. and ollower aw, be- that it re with up the the end 1 runa front the ge 130) ApRIL, 1929 Now. for faster, easter cutting New- Model Disston Hand Saws 1—Lighter Blades 4—Thin, yet Stiff -—for true running 5—New Handles —give better balance 6—Disston Steel —stays sharp longer POPULAR SCIENCE MONTHLY —for easier cutting 2—Narrower Blades —save strength 3—True-Taper Grind py my | ype —forfaster cutting | leiiects fs cineae ties and from handle to point. Tooth edge is of even thickness from end to end. Never until now could you get blades so thin, so stiff, so light, to cut fast and run true. HE Saw Most Carpenters Use now comes to you in entirely new models, improved in every feature. These new Disston Hand Saws will run with less set... cut faster ...cut easier ... stay sharp longer, than any other hand saws ever made. They have better clearance, better bal- ance, better steel, better temper, and will give you better service. They are lighter, with blades thinner, yet stiff, always the goal of saw makers, first achieved by Disston. Now made possi- ble only by Disston Steel. And you know this: The thinner a blade is, if it is stiff, the better it cuts and the easier it is to use. The new Disston D-8 Lightweight Saw weighs only 1 Ib., 7 oz. in 26-inch length Less weight to push: less work for you. Thinner, yet stiff, 1t cuts faster and easier, like all the fourteen other hand saws in the new Disston line. Handles of new design, with larger handholes, for a more comfort- able grip, give perfect balance and new ease in using. These handles have a new and finer finish, weatherproofed to prevent warping. There is no strain on the wrist, no drag on the arm. Every blade “follows through” as never a hand saw could before. Whatever style of saw you want, you will find it in the new line of Disston Hand Saws at your hardware store. Get This Helpful Book Every saw user will enjoy reading “The Disston Saw, Tool and File Book,” an illus- trated manual on the selection, care and use of tools. It tells how to file and set saws and contains much other helpful in- formation. The coupon below will bring it. DISSTO Makers of “THE SAW MOST CARPENTERS USE” Use the right saws and in the home workshop Good tools, and correct tools, are required for good work. These are some of the Disston Tools needed in the home shop. No.4 Back Saw—Handiest of allsmallsaws. Fine teeth and stiff back enable you to do the smooth, even cutting that isso neces- for work in cabinet making, etc. Can be used in mitre box. The 12-inc size, 8 inches under back, with teeth l4points to inch, is most popular. $3.00. No. 68 Dovetail Sew=Used ta pattern and inet making where extra thin saw fav teeth is needed. Eight-inch biade, If points, is most popular. $1.60. D-3 Filing Guide and sharpen saws in tooth at the same angle. Adjustable for both rip and cross-cut saws. Complete with rections. $6.50. ss No.28 Triumph Saw Set—Gives perfect set on hand saws, k saws, web saws, band saws, etc., 10 points to the inch or coarser. The most efficient tool for the purpose. $1.50, Disston Files—File your saws with Disston Special Extra-Slim Blunt Saw Files. Special teeth, cut better; parallel sides; extra-slim; Disston-made steel. 5-inch, 20c; 64-inch, 20c; 6-inch, 25¢; 7-inch, 80c. There is a Disston File for every purpose. No. 120 Acme Cabinet Scraper—Needed on every work bench. Made from_Disston Saw Steel, hi tempered, ground even gauge, dressed on edges. Made in all needed sizes, 244” and ig wide and 6” and 6” long being standard. 25 cents and up according to size. A-10 Lightweight Pocket Level—Li pet he a -Madeof airplanealum _~ cannot rust. Weight only two ounces; length nine inches. ed lines on level and two plumb glasses are proved. $1.25. Henry Disston & Sons, Inc., Philadelphia, U. S. A. (In Canada, address Henry Disston & Sons, Ltd., Toronto) Please send me “‘The Disston Saw, Tool and File Book.” © This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8.

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One Benc Designed for Home | Workshop Use, ItIs | of Heavy-DutyType Yet Easy to Build By E. E. ERICSON and every man who does much household repair work needs a fairly large, rigid workbench. Wher- ever there is room available—in the basement, garage, or large attic— vad ey amateur woodworker POPULAR SCIENCE MONTHLY h That's Big Enough the bench illustrated will make its |) appeal to the worker because of its | | strength, durability, and simplicity | of design and construction. A bill of lumber is the first con- cern of anyone who wishes to con- struct this bench. The wood can be obtained at any lumberyard. Hard (yellow) pine can be used throughout with the exception of the leg at the vise and the vise jaw, which should be made of maple or a similar hard- wood. The top also will be better if of hardwood, but the construction will be a little more difficult. For convenience two separate lists are given (on page 130): first, the lumber order as it may be turned over to the mill or lumberyard; second, a stock bill showing the actual widths and thick- nesses of planed lumber as it comes from the mill and the finished sizes to which the material must be cut by the worker himself. The pieces may vary slightly from the dimensions stated, but the variations will not materially affect the finished workbench. The following order of procedure is sug- gested: 1. Cut the four legs to the required length. (The length indicated in the drawing, 30 in., is a good, standard height.) Attach the vise-screw nut. 2. Cut the two upper cross rails for the ends to the length given. é A man-size bench of the carpenter’s type for the amateur mechanic who does much woodworking and repairing. penny box nails or common nails in each joint. Check for squareness with a steel square. 6. Glue and nail the piece of 13¢-in. maple on the face of the vise leg as shown in the drawing. This should not be cut to length at this time, but should be trimmed even with the surface of the top after the top is applied. 7. Cut the two aprons to the proper length (first checking the length of the pietes for the top). Cut away from one of them the part displaced by the piece of maple facing on the front leg previously mentioned; then glue and nail them in place. Use the square frequently while nailing up the frame. 8. Take the actual measurement for the stretcher or shelf that runs between the two lower cross rails. If desired, this can be made to overlap a little at each end for effect. This wide stretcher will serve as a shelf for tools and materials. 9. Cut out the place for the drawer on the front apron. This is best done by 8. Cut lower rails. 4. Hold all four teowwnnnd legs together with a hand screw or other ts clamp in such a way tt that their outer edges 2 are exposed. With pencil and square, draw crosslines to in- dicate the location of - 7-0 “8 the cross rails. The —T . = ~ Io | upper rails act also Ht ane EE | > DRAWER ts by0 i tt as backs for the tool i 7 7 ae i= } f compartments. ile ; EE Fecemnc=- seamed g lo Ri 5, Now nail up the = two ends for the ; bench, using glue in one the joints for added OO a , rigidity , and not less 0 Top, front, and end view of the bench, ‘o than three eight- and a detail of the stationary vise jaw. ! APRIL, 1999 boring holes in two diagonal of the rectangle to be taken out starting the cuts with a Compass keyhole saw. ™ 10. Fit one of the 9-in. boards each side of this opening, - them also support the top at thes points. Before fastening these boards, nail on them the slats whic, form supports for the drawer, 11. Fit the shelves in the ends, nailing them to the under edge of the cross rails or against these rails as may be determined by the width of the boards and the distance the aprons extend. 12. Joint (plane the edges) and glue up the two planks for the top, Use four }4-in. dowels for the joint, Care must be taken to mark argy. rately for the dowels; use a marking gage, knife, and square. 13. Trim the top to the length of the aprons and fasten it with 24 in, No. 12 flathead screws. First bore a 44-inch hole 14 in. deep to receive each screw; then drill a hole right through into which the screw thread will slip easily. Hold the top in place, drill 3%-in. holes into the rails, drive the screws, and glue plugs into the 14-in. holes, 14. Cut the board for the bottom of the tool trough for length and also for width, if necessary. Nail this in place and nail on the strip along its outer edge, 15. Form the vise jaw to required shape, making it about 7 in. at the top and 41% in. at the bottom. Plane a bevd on the outer edges of this, but do not at- tempt to finish the top end of it until after the vise screw and the follower have been fitted. 16. Clamp the vise jaw in place with the upper end protruding slightly above the top. Locate center of vise screw to coincide with the flanged nut center; bore a hole to allow screw to pass freely, and fasten collar. 17. Now tighten up the vise and bore a series of holes through both jaw and leg in one operation for the follower or “lock strip.”” These holes should form a slot nearly the full size of the cross section of the follower, that is, 3% by 3 in. Then chisel out for a tight fit in the jaw anda sliding fit in the leg. 18. Bore a series of holes 1% in. in d- ameter through the follower in a zigzag pattern about 1 in wpart, as shown. 19. Glue and dowel the follower into the vise jaw, be- ing particular that it is put in square with the jaw. 20. Tighten p the vise, plane off the end of the jaw, and run a bevel on the front side of it. 21. Make the (Continued on page 130) — DETAIL ‘OF CONST RUC1 iON AT VISE —23"-—_—__+ SE a ' TOOL ' ‘COMPARTMENT : ¢ = - 2, | ened ofS

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RIL, 1999 a bevel ) not at- ve been ce with y above crew to er; bore ly, and nd bore and leg r “lock a slot tion of Then a tight and a he leg. series in di- th the zigzag 1 in and »llower iw, be- that it e with np the he end run a front the re 130)

ApRIL, 1929 Now. or faster, easter cutting New-Model Disston Hand Saws

1—Lighter Blades 4—Thin, yet Stiff —for true running 5—New Handles —give better balance 6—Disston Steel —stays sharp longer POPULAR SCIENCE MONTHLY

—for easier cutting 2—Narrower Blades —save strength - Bere - —_ ° isston wes are ground with a 3—True-Taper Grind true double, taper and run smoother My t is true r ua’ =f orf aster cutting enldecumiy from cutting’ ed to back and from handle to point. Tooth edge is of even thickness from end to end. Never until now could you get blades so thin, so stiff, so light, to cut fast and run true.

HE Saw Most Carpenters Use now comes to you in entirely new models, improved in every feature. These new Disston Hand Saws will run with less set... cut faster ...cut easier ... stay sharp longer, than any other hand saws ever made. They have better clearance, better bal- ance, better steel, better temper, and will give you better service. They are lighter, with blades thinner, yet stiff, always the goal of saw makers, first achieved by Disston. Now made possi- ble only by Disston Steel. And you know this: The thinner a blade is, if it is stiff, the better it cuts and the easier it is to use.

The new Disston D-8 ‘Lightweight Saw welahe only 1 Ib., 7 oz. in 26-inch length Less weight to push: less work for you. Thinner, yet stiff, 1t cuts faster and easier, like all the fourteen ‘other hand saws in the new Disston line. Handles of new design, with larger handholes, for a more comfort- able grip, give perfect balance and newease in using. These handles have a new and finer finish, weatherproofed to prevent warping. There is no strain on the wrist, no drag on the arm. Every blade “follows through” as never a hand saw could before. Whatever style of saw you want, you will find it in the new line of Disston Hand Saws at your hardware store. Get This Helpful Book Every saw user will enjoy reading “The Disston Saw, Tool and File Book,” an illus- trated manual on the selection, care and use of tools. It tells how to file and set saws and contains much other helpful in- formation. The coupon below will bring it.

DISSTON Makers of “THE SAW MOST CARPENTERS USE” Use the right saws and files in the home workshop Good tools, and correct tools, are required for good work. These are some of the Disston Tools needed in the home shop.

No.4 Back Saw—Handiest of allsmallsaws. Fine teeth and stiff back enable you to do the smooth, even cutting that isso neces- sary for accurate w work in cabinet makin . Can be used in mitre box. The 12-ineh size, $ inches under back, wi sp teeta Lege nts to inch, is most popular. $3.00 a pe maki: Se ag ih Ba’ ne where extra thin saw fine teeth is needed, Eight-inch blade, If points, is most popular. $1.60.

D-3 Filing Guide end Clamp Basbies any one to cilapen — tooth at the same angle rip and . om saws. rections. "Aajaatbe fa for k bote ( 2 5 Z Ni So. 28 TeinmphGowSee-Gis ves perfect set saws, 9 0; ante “to the Tou inch or coars: The most efficient tool for the paspane. $1 oh Disston Files—File your saws with Disstoe Special ey Blunt Saw Files. Special teeth, cut be 5 parallel sides; extra-slim; Segtnn neni ote 65-inch, 20¢; 634-inch, 20¢; 6-inch, 25c; 7-inch, 80c. There -y a Disston File for every purpose. No. 120 Acme Cabinet Scrap on every work | bench. Made from_Disston Saw Steel, hi tempere Eauge, dre even —

in all needed sizes, 24” and 2 5” and 6” long being wo Hy Pvige | up according to size, “——- q<m. 23 ?p

pon ae lord cMadcofairolanealumtncme a pm rust. poe only two ounces nine inches. ed a 33 = and length plumb glasses are proved

Henry Disston & Sons, Inc., Philadelphia, i (In Canada, address Henry Disston & Sons, Ltd., Toronto) Please send me “‘The Disston Saw, Tool and File Book.”

© This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8.

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F THERE are a dozen ways of distorting work held against the faceplate or machine table, there are at least as many of doing the same thing with the chuck. Every mechanic is familiar with the difficulties of holding a thin ring without causing it to go out of round, but it is not so gen- erally realized how thick a ring or tubular part may be and yet be distorted by the pressure of chuck jaws under certain condi- tions. Any good lathe chuck is ca- pable of exerting powerful pres- sure, which may cause an appre- ciable deformation in a ring such as that shown in Fig. 1 at A. This deformation is usually in- , by Mn F “Ce mote nant “It was large enough while in the lathe chuck,”’ gen in cutting. le the said Old Bill, “but now it has sprung out of A Light H POPULAR SCIENCE MONTHLY effect of heat will not be treated shape and the hole is no longer truly round.” in this article, it should be re- membered that expansion from heat will produce a condition similar to that which results from excessive tightehing of the chuck jaws. It should be observed that the deforma- tion of the ring is not the same as the reduction of the diameters in line with the jaws. As the circumference of the ring remains practically unaffected by the pressure, some portions must seem unlikely that the jaws could cause any change, the work may yet be de- formed because of the uneven bearing of the jaws on the surface of the work. At A in Fig. 3, the slight projection a on the rough casting has the effect of concentrat- ing the pressure at that point when the jaw 1s tightened as at B, with the result shown at (. and on the Wrench Often Prevents the Serious Distortion of Work Held in Lathes or Other Machines, According to HENRY SIMON, Expert on Better Shop Methods Apri, 190 An analogous effect results where the registering surface of the work is slight] tapering, as at D, Fig. 4, or by ta 7 surfaces or play in the chuck jaws, as at f Happily; the remedies for these troy, bles are simple. The main thing to k clearly in mind is when and hoy the various distorting agencig are likely to operate. The firg rule, of course, is: to: avoid yp. necessarily heavy clamping, and to remember that a solid may become a frail object by the time it has been bored anf turned. i THE absence of cuttj compound, the simple muled allowing the work to cool befor taking the finishing cuts—ngy partly, as is too often the case but completely—will go fy towards preventing trouble from pressure due to heat expansion, Pouring cutting compound ove the hot part and into a pan underneathis a quicker way, but with delicate parts such sudden cooling is likely to set uw strains in the metal which may be trouble some later. When a finished piece of work is to have thin walls, yet must be made from a solid piece, the stock should be clamped hardat first so as to remain secure under the heavy roughing cut and then be pushed outward by about be reset with lighter pressure the amount that other por- for finishing. This resetting tions are displaced inwardly, Or BILL stopped at a 20-in. lathe where one of may often seem inconvenient, as happens in converting the his apprentices was boring a small eccentric yet it will pay in the end, e circle in the diagram at B into strap for a hoisting engine. He observed that the pecially as it will also mini a square of equal perimeter. a SS ey ede ph Diy ce mize the results of other + a age . B gusgere prac- | comsect. The parts should go together without — released during cut- Ucally oubled, as shown In trouble. ; ing. - view C. But—something caught his eye which led him to In Fig. 5 is pointed out one ; ; suspect trouble. He instructed the boy to remove way that may lead to trouble FIRST cousin to this the strap from the chuck, take it apart, and assem- on work held between cen- type of trouble is that re- ble the halves about the eccentric. ters. With the dog placed sulting from boring out solid | Much to the apprentice’s consternation, the that near the end of the piece, work to a shell, as in Fig. 2 | halves would not close about the eccentric, and he and with only a point bearing at A and B. Being solid, the | exclaimed, “I am sure that I had the bore large on the screw against two line work is strongly clamped at enough!” bearings in the vee as at A, the beginning to hold it Old Bill ‘could not resist a temptation to smile at the condition shown exag- against heavy, drilling and the boy’s expense, but said kindly, “It was large gerated at B.may easily oc- boring cuts. As the job pro- enough while it was in the lathe chuck, but it is not cur. The resulting motion d ceeds, the heat generated ex- the same shape now as then, for you had it clamped the work during the grindi so tightly that you sprung the casting in at four er pands the work as well as the points, and the intermediate points sprang out operation is shown at C, chuck jaws, setting them still which was the condition when you bored the hole the result at D. Though dis harder against the work, round. Now it has sprung back to the original alignment of the center may whieh is now hollow and has shape, and the hole is no longer round, but has a be very slight, yet, on an ac a wall of constantly decreas- wavy outline, like this—’’? Old Bill made a rapid curate part such as_ that ing thickness. By the time sketch with chalk on the bench. shown, the effect on the the job is done and the work In this manner was one of Old Bill’s apprentices truth of the flange may be removed from the lathe, the introduced to the mysteries of elasticity in metals, painfully noticeable. hole is out of round as at C. a property discussed in the accompanying article. Another and more com- Even where the wall of the mon, yet frequently unsus § work is so thick that it would (Continued on page 98) » best ow”

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Apart, 1929 where the is slightly y ta VS, as at E hese troy. 1g to k , and re rene The first avoid un ping, and solid part ect by the ored and f cutti dle ruled Cuts—gp; the case 80 far ible from <pansion, und over Tneath is ite parts O set up trouble. 3 to have n a solid 1 hardat ider the ind then pressure "esetting venient, end, es- 30 mini- f other ing cut- out one trouble en cen. placed € piece, bearing wo line s at A, a exag- sily oc. tion of rindi C. gh dis Tr may an at n the ay be com- unsus- 8)

POPULAR SCIENCE MONTHLY

They use Starrett Tools wher- ever things have got to be right AKING down a ‘“‘Whirlwind”’ or a ‘‘Wasp” for major overhaul comes only at twenty, even thirty thousand mile intervals. When it is done, it is done with a thoroughness that has for its basis the heavy responsibility of assuring unfaltering performance. Aircraft motor manufacturers and transport operators alike rely on the accuracy and de- pendability of Starrett Tools. You, too, want Starrett accu- racy and dependability, no matter whether you use tools for serious work or as a hobby. You’re not satisfied with any- thing but the best.

Whenever you buy a precision tool, hacksaw or steel tape, see that it bears the Starrett name. Your dealer will gladly show you genuine Starretts. Let us mail you a free copy of the great Starrett Catalog No. 24“W” illustrating and de- scribing more than _ 2500 Starrett Tools. THE L. S. STARRETT CO. e Sta World’s-Greatest Toolmakers Steel Tapes—Standard for Accuracy ATHOL, MASS., U.S. A.

Orr © This seal on an advertisement.in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. tt To Manufacturers of Hacksaws Unexcelled ols

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A Light Hand on POPULAR SCIENCE MONTHLY (Continued from page 96) f pected, cause of trouble is shown in | Fig. 6. Here the vee in the dog is slightly hollow, as indicated at a. As a result the part bears only at the outer ends and the screw may bend it as shown, displacing the axis. Care, watchfulness, and _fore- thought, together with a light hand on the wrench, are here also the larger parts of the solution. Another point, and one frequently sinned against, is the proper selection and size of the dog. For the mechanic who likes to put his odd moments to use, a simple and useful “‘trouble-proof’’ dog for | light work is shown in Fig. 7. This is easily made from some scraps of square cold-rolled steel and is so de- signed that it cannot cause any dis- | tortion, since it alwayscentersevenly | on the work all the way around. A | few dogs of this kind are easily made | APRIL, 1999 the Wrench sary for a finishing cut. A of 50 lbs. per clamp would be anal One way in which compression is frequently enabled to get in jt, work where one would not Suspect it is pictured in Fig. 10. Viewed under a strong magnifying the smooth surface of the faceplate or machine table, as well as that of the work, looks like a plowed field. Magnified a good Many times, a cross section of either work or table would look something like at A, although in practice the lower surface will almost always be in the same condition, so that the pieces touch each other only at a number of points marked by the high ridges of innumerable intersecting fur. rows. Under such conditions moderate force may be enough to compress the parts into each other How thick rings or © | | even solid stock may be distorted by be- ing badly clamped. to the extent of a few ten-thou. sandths. It may be well to conclude by considering how compression acts on two flat parts under different | conditions, as by the action of the sion, but it will rarely amount to FIG. 4 4 1) Z A, Z Z 7A E Y DU enough by itself to make any real difference. This will be clear when 24] . Distortion caused by tapered work, by play in chuck jaws, and by improper use of dogs. we look at the diagrams C in Fig. 8, where it will be seen, for in- stance, that a pressure of 1,000 Ibs. would be required to compress a solid cast-iron cylinder 1 in. in diameter and 1 in. high by as little as .0001 in. It will be understood that when we speak of compression, what is meant is only the elastic “give.” Enormously greater pressures would be required to deform the material permanently. bolt shown in Fig. 11. With the bolt ends equal, a plate of solid metal is com. pressed equally from both sides as at A. The effect is the same with two plates of the same material, as at B, the plane of contact remaining straight. This is not the case when one of the members is harder, as the steel part a at C. Here the softer cast-iron member b is compressed from the bolthead and from the sted plate, and a bending effect is thus pro- duced in the latter. A similar bending strain results when a larger hardened washer is used against one or the other of = plates of the same material, as at D and E. The troubles sometimes thought to result from compression are almost always due to bending strains caused by a dent or “dish”’ in the surface of the work, as at D, or the same condition in the faceplate, as at E, or both, as at F. and will be found a help in grinding many kinds of small work. The strains we have so far been consid- ering in this article all were in the nature of bending. Is it possible under ordinary working conditions to compress metal so that trouble will result? To illustrate the difference by the diagram in Fig. 8— knowing that we can distort the part a when held as at A, are we apt to change its shape by compressing the metal as at _B? Some mechanics will say “yes” to this question; others will undoubtedly say “‘no.”” What is the truth? It may be said at once that the truth, though it lies between the two extremes, is much nearer the “no” side. Distortion may occur as the result of pure compres- i» FIG. 9 is shown an in- stance where a part may be distorted enough by pure com- pression to produce an error. With the registering surface of | the part and the working sur- | face of,the clamp as narrow as they are, a force of, say, 200 lIbs..on the clamp be- comes a pressure of thousands of pounds per square inch, so ! i Brass on £000! ALUMINUM) that the part will be com- pressed centrally by several ten-thousandths. It should be added, however, that any such pressure as 200 Ibs. on the clamp, though it is often used, is far in excess of that neces- Trouble-proof dog for light work, and diagrams illustrating effects of compression in clamping work. APRIL, th wo oo

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PRIL, 1999 Pressure € ample, PESSION ig t in its ’ Suspect Viewed 8 glass, aceplate 3 that of Plowed l Many er Work Ing like 1€ lower in the > Pieces number h ridges ig fur. ‘ons a ugh to h other 1-thou- ide by ferent of the 1e bolt § COm- at A, ites of ane of is not es is re the steel | pro- nding lened er of at D POPULAR SCIENCE MONTHLY 101 ApRIL, 1929 the Largest Prize Contest in Photographic History in Cash Awards Grand Prize $2,500... 11 Prizes of $500 each... 11 Prizes of $250 each... 125 Prizes of $100 each... 1,223 Money Prizes in All. . . for snapshots, time-exposures, enlargements . . . only strictly amateur photographers may compete... Every picture-taker has an equal chance to win! spark of interest in it, don’t fail to send it in. What looks to you like a “flop” may look like a “wow” to the judges. This award gives you 106 chances to win: (1) You can enter the March contest for the best child picture from each state, (2) You can enter the April contest for the best child picture from each state, (3) The pictures that you have entered for the state contest during either of these months and pictures that reach Rochester during May are all eligible for the Grand Prize of $2,500 or for any of the one hundred three prizes in Awards No. 2, No. 3, No. 4, or No. 10. AWARD NO. 1—Scenics—For the best picture of any city or country outdoor scene . . . a first prize of $500; a second of $250; a third of $100; 25 prizes of $10 each and 75 prizes of $5 each. Here's your chance to capitalize your ability to spot an interesting outdoor subject. Landscapes and marines, distant and nearby views, mountains and water, nearby bits of nature com- position, travel subjects and street scenes. ; AWARD NO. 2—Informal Portraits—Pictures made at from, say two to ten feet distance, for the purpose of showing a person's features... a first prize of $500; a second of $250; a third of $100; 25 prizes of $10 each and 75 prizes of $5 each. AWARD NO. 3—Story-Telling Pictures—For the pictures telling the most interesting story . . . a first prize of $500; a second of $250; a third of $100; 25 prizes of $10 each and 75 prizes of $5 each. Take a picture in which children, adults or animals do something—any- thing except looking at the camera. For instance, a puppy pulling at a baby’s sleeve; children in any form of play; father proudly exhibiting the new car toa friend. There are any number of opportunities for you to take pictures like these. AWARD NO. 4—Sport Pictures—For the best pictures of sports and games. . . a first prize of $500; a second of $250; a third of $100; 25 prizes of $10 each and 75 prizes of $5 each. It may be skating or coasting or skiing— or baseball, tennis, golf. Hiking, too . . . and boating, archery, polo riding — all serve as opportunities to make prize winning pictures. AWARD NO. 5—Animal Pictures—For the best pictures of pets, live stock, wild animals, either at large or in zoos. . .a first prize of $500; a second of $250; a third of $100; 25 prizes of $10 each and 75 prizes of $5 each. AWARD NO. 6—Nature Study Pictures—For the best pictures of flowers, birds, butterflies, leaves, rocks, spiderwebs, any nature subject... a first prize of $500; a second of $250; a third of $100; 25 prizes of $10 each and 75 prizes of $5 each. AWARD NO. 7—Building and Architectural Detail—For the best exteriors of homes, churches, schools, offices, libraries, other buildings, or portions thereof . . . a first prize of $500; a second of $250; a third of $100; 25 prizes of $10 each and 75 prizes of $5 each. AWARD NO. 8—Interior Pictures—For the best inside views of rooms, corridors, staircases, or other portions of homes or other buildings ...a first prize of $500; a second of $250; a third of $100; 25 prizes of $10 each and 75 prizes of $5 each. AWARD NO. 9—Still Life Studies—For the best pictures of art objects, curios, cut flowers, any still-life subjects in artistic arrangement . . . a first prize of $500; a second of $250; a third of $100; 25 prizes of $10 each and 75 prizes of $5 each. AWARD NO. 10—Unusual Photographs—For the best pictures made at night; pictures of fires, lightning, storms, silhouettes; or any pictures that are unusual either as to topic or as to photographic treatment... a first prize of $500; a second of $25C: a third of $100; 25 prizes of $10 each and 75 prizes of $5 each. Special Prizes for Enlar ;ements— $1,350— Any picture isa better picture when enlarged. For the best enlargements from negatives made on or after March 1, 1929 . . . a first prize of $500; a second of $250; a third of $100; 25 prizes of $10 and 50 prizes of $5 each. Your film dealer or photo- finisher will be glad to help you choose a picture likely to win. (See Con- ditions Nos. 2 and 4.) Each of these big cash prizes will have to be won by somebody .. . why not you! Aim at the big money and you stand an excellent chance of winning it or of coming in for one of the smaller prizes. Don’t miss this chance of winning a share of the big prize money. There is always the certainty of being rewarded with some excellunt pictures you might otherwise fail to get. THESE ARE THE JUDGES. Observe how diversified are their interests and how broad are their viewpoints and experience. You must admit that no fairer Board of Judges could be assembled than that represented here: Madame Galli-Curci, internationally known singer; Miss Ethel Barrymore, leading actress; Howard Chandler Christy, noted artist; Clare Briggs, famous cartoonist; James R. Quirk, publisher, Photoplay magazine; Rudolf Eickemeyer, distinguished photographer, Medalist Royal Photographic Society of Great Britain; Hector Charlesworth, author, critic, editor “Toronto Saturday Night”; Kenneth Wilson Williams, editor “Kodakery™ and photographic expert. For the two Monthly Child Picture Contests, the following will be judges: James R. Quirk, Rudolf Eickemeyer, Kenneth Wilson Williams. NOW -—vead the simple Contest Conditions and get your camera out! Kodak Film in the familiar yellow box is dependably uniform. Reduces the danger of under- or over-exposure. It gets the picture. iO is ee 2. eo Fe ee CP RPA ae (Please Print) ene DUGG: ... 6.0: ss: 5.900062 43 Beasng edamame POE BOE. BEG, oo ~ 0:0, 0-0 5.8:0:410000-65:0) ae be eee Make of Make of Re ee eee ere re i err Peres Enclose this blank with your entry and mail to Prize Contest Office, Eastman Kodak Company, Rochester, N. Y Do not place your name on either the front or the back of any pic- ! ture. Be sure that each entry in the State Child Picture Contest is so designated on the back. |

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102 POPULAR SCIENCE MONTHLY NOW: / 4 safe, accurate, practical woodworker —in the “popular-priced” field Your chance to get a complete, compact, handy DeWalt Wood Worker at a popu- larly low price. Just the machine for general use in any amps: or shop. Use portably or stationary— r making and repairing screens, shelves, benches, bins, crates, boxes and furniture. The ‘‘Junior’’ DeWalt rips, cross-cuts, bevels, miters, dados, gains, ploughs, rab- bets, shapes, routs, tenons, grinds and bores with ease, speed and accuracy. It’s a complete woodworking machine which — any material up to two inches £ ° Superior in every way to other types of machines. Comes all complete, ready to run, with universal motor to suit any current. Just plug in and start to work. We also make the heavier DeWalt Wood Workers, Band Saws, Jointers and Mortis- F ers, which are used throughout every woodworking industry. Only *19582 Complete with motor, table, saw blade, safety guard, switch and connecting cord. Mail Coupon Today! JUNIOR’ De WALT All Purpose Wood Worker ! DeWALT PRODUCTS CORPORATION 742 New Holland Ave., Leola, Penna. j Please send immediately full perticulere of die tnieniia teal l the “Junior” DeWalt All Purpose Wood | Worker. tev IR TI ln a ie riet a ci dk cask gli nbck6 b 46leo 0044.4A « aN: i alias te ia ates ceca Sb dds des Os: Gina an Emptying a Washing Machine Controlling a Bathroom Light— And Hints for Home Owners ally have a built-in drain in the basement or laundry, older houses Maly hav houses built today usu- frequently lack this convenience, and the laundress has to drain the washing ma- chine into pails, which must be lifted to the laundry tubs or carried to a drain. To avoid this work, the writer has con- structed an attachment to replace the faucets; it will both fill and drain the washing machine. The attachment oper- ates much like an injector for a steam boiler. The materials required are shown in Fig. 1. All the fittings are standard Y-in. pipe fittings until the 45-degree tee is reached, at which point a step up to 34 in. is required. This is necessary because the 45-degree tee, which houses the nozzle to build up the velocity of the water, must also be of a capacity to carry away the additional water which is being drained. The step-up is accomplished by a reducing bushing, which also acts as a holder for the pressure nozzle. The pressure nozzle is made of a piece of round brass with a 4-in. hole drilled clear through. The nozzle is sweated into the reducing bushing and should be of a length sufficient to reach almost to the lower end of the tee. The lower end of the nozzle is tapered to allow maximum space for the incoming water. The two upper valves should be of the compression type, while the lower one must be a gate valve. To fill the washing machine, the gate Fig. 1. Attachment for emptying a washing machine. The construction is shown at right. valve is closed and one or both of the compression valves are opened. The water then passes through the side outlet of the 45-degree tee and through the hose to the machine. To drain, place the end of the hose in the water, close the gate valve, open the compression valve on the cold water side, and then again open the gate Fig. 2. Extension tape makes it possible for children to turn on and off a bathroom light. valve. This creates a siphoning effect, One point must be observed when draining—the gate valve must be kept closed until the hose has filled with water, then, when the gate valve is opened, the water leaves the orifice of the nozzle at high velocity and acts on the column of water retained by the hose, causing it to follow in the same direction. The rapidity with which the washing machine can be drained in this manneris quite surprising. The writer has draineda| forty-gallon tank in six minutes. And no labor is wasted.—R. H. Kasper. | peg accessible to| both little folks and! adults is the bathroom light switch illustrated in Fig. 2. It is made by attaching a tape to th end of the chain of & chain type socket. The tape is run through 4) screw eye at the top| (Continued on page 131) DRAIN Eee ES P}) PE—~—@ VALVE (INECTOR PRINCIPLE) ee

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ible for n light. z effect, 1 when be kept n water; POPULAR SCIENCE MONTHLY Apt, 1929 Born - - - - March 1, 1929 ~ | ed, the ozzle at | ‘umn of | ng it to washing anner is aineda And no sible to! lks and| throom strated ade by to the! n of 4 t. The ugh 4) 1e top 131) | MILLERS FALLS CO. © This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. E Ci PLE) of Distinguished Parentage MILLERS FALLS TOOLS No. 9 Smooth—Length 9 in. Cutter—2 in. Weight 33 Ibs. A Complete Line of Planes by Millers Falls ERE’S a brand-new line of fine planes made by a manufacturer who’s been at this business of making fine tools for half a century. At first glance they look much like the planes you’ve known. It’s after you use them that you note the difference. Built Around the Cutting Edge Millers Falls planes are built around just one feature, the cutting edge. Our engineers began with steel. Years of experience in selecting and elec- eee treating of fine tool steels have resulted in refinements that make Millers Falls plane cutters last longer and hold a finer edge. Other New Features Next the designers tackled chatter- ing. The precision with which the blade is held at the correct cutting angle, determines how well the planc does its work. So new features were added, such as 3- — bearing of lever cap, mak- g,,. ’ ing possible hair breadth adjust- Hi ment that holds } and overcomes {t chatter. Made for Tool Users Practical carpenters, cabinet makers, men who love good tools for home shop- work — anyone who uses a plane will delight in the balance, com- ciency of Millets NEW YORK: 28 Warren St. Falls planes. Sizes.in bench planes from 7 inches to 24 inches, smooth and corrugated bottoms, and 21 models of block planes, cover every plane need. Sold by Responsible Dealers Millers Falls planes will be found in the stores of leading hardware merchants./The mere fact that a dealer offers you Millers Falls is proof that he desires to sell you truly fine tools and so win your permanent patron- age and good will. A new catalog for tool users is ready. Send today for free copy with- out obligation. It shows a wide vari- ety for your choice in 14 major tool lines. © MILLERS FALLS, Massachusetts CHICAGO: 9 So. Clinton Se.

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104 This announcement has brought mew vision and inspiration to am- bitious thousands who hungered for wider, deeper culture. A Background that Will Broaden Any Mind Examine it FREE POPULAR SCIENCE MONTHLY HISTORY SCIENCE LITERATURE ART RELIGION PHILOSOPHY Brings You UP-TO-DATE On Every Subject Now you can have at your command what man has learned in the six greatest branches of human knowledge and culture. Six great romantic outlines, six comprehen- sive sections that will bring you—com- pressed into one 700-page volume—the thrilling story of the world’s HISTORY down to date—the stirring march and trends of RELIGION —the thought and wisdom of man’s PHILOSOPHY —the intriguing beauty of the ARTS—the all- embracing survey of every branch of SCIENCE— and a complete panorama of the world’s LITERA- TURE from the first Neolithic scribblings to the work of modern authors of all nations. A Liberal Education In Narrative Form THE OUTLINE OF MAN’S KNOWLEDGE, by Clement Wood, is the ONE book, the only book, that gives you the fascinating story of what man has learned and accomplished from the world’s birth in a flare of meteoric splendor up to the arrival of radio, aviation and television. Here is the whole story—all of it—Science, Art, Literature, His- tory, Philosaphy and Religion—in one large beautiful volume that you can actually BORROW for a week at our expense. It is the book which the Philadelphia Public Ledger declares is ‘“‘the ONE book to read and know,” and of which the Pittsburgh Sun-Tele- - if.”’ graph writes, “It is a university in itself. The Essence of ALL Knowledge Complete in Only ONE Volume Clip and mail the convenient coupon and it will bring you, prepaid, a copy of THE OUTLINE OF MAN’S KNOWLEDGE. Examine it. See for yourself how fascinating is the story of knowledge. Read it freely for a week. See how much you have missed in the realm of things you OUGHT TO KNOW. If you are not completely satisfied send the book back within seven days. Otherwise, keep it as your very own and remit the astoundingly low price of only $1.50 and two dollars a month for two months thereafter. Send No Money—BORROW It at Our Expense But don’t decide now. See this all absorbing work first. You can do that at our expense. Send no money. Just clip the coupon. Do it before the present edition is exhausted. Fill in the coupon and mail it at once. LEWIS COPELAND COMPANY, Dept. 97, 119 West 57th St., New York, N. Y, Tear Off Along This Line and Mail Today LEWIS COPELAND COMPANY, Dept. 97, 119 West 57th St., New York, N. Y. Kindly send me THE OUTLINE OF MAN'S KNOWLEDGE, by Clement Wood, 700 | illustrated, handsomely bound. Within 7 days i will either return the book or remit $1.50 as first Payment, and then $2.00 per month for two months, a total of $5.50. (Ten percent discount for cash with order. Same return privilege.) Cand ébknoms ase s Ge owe eerie ; ee eee ORs ed aheKkeeSeeSES4e RmEwA If outside continental U. S. send $5.00 with order. Turning a Flag into an Kee Is an Easy Trick with Which to Mystify Your Friends if You Know What Preparations to Make __ By GrEorGE S. GREENE | is a most effective one for the amateur magician, a silk flag is stuffed into the cupped hands, yet when the hands are opened nothing is seen but an egg. To prepare for the trick, chip a hole the size of a quarter in the side of an egg with a knife and allow the contents to flow out. The remaining egg shell must be handled carefully. A tablespoon of plaster of Paris is mixed with water until a thin paste is formed, and this poured into the egg. The shell must be kept continually in motion until the plaster sets, so that the entire inside will be coated with a ie THE flag and the egg trick, which Apru, 1929 a thin layer of the plaster. When the | plaster is quite hard, the hole may he trimmed and smoothed up. In this con- dition the egg may be handled without breaking. Before the trick is performed, the pre. pared egg is deposited in the pocket with a silk flag. When the time comes, the egg, covered by the flag, is removed from the pocket. The hands are cupped to. gether around the egg, and the middle fingers are used to stuff the flag slowly into the egg. The latter may then be exhibited as a genuine, unprepared egg, with the fingers held over the hole s9 that it will not be seen. A hole the size of a quarter is chipped in one side of the egg, but great care must be taken not to crack the shell. Stuffing in the flag. In actual per- formance the hands conceal the egg. ‘ Taking Pictures Backwards for Amateur Movies GET reversed motion with an amateur movie camera, merely hold it upside down while taking the particular scene which you want to film backwards. When the roll is returned to you, sepa- rate the reversed scene and splice it in, turning it end for end so that it will run right side up in the projection machine. How the egg is re- moved from the pocket under cover of the silk flag. Plaster is poured into the egg, which is kept continu- ally in motion until a thin, hard lining is formed inside. When the egg is revealed and ex- hibited, two fingers conceal the hole. There are many amusing tricks possible with backward motion. A person drop- ping from a high wall when taken in this way will appear on the screen to jump from the ground to the top of the wall. Two automobiles photographed as they back rapidly away from eacb. other will appear to collide.—H. N. Wuirmore.:

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"RIL, 1999 POPULAR SCIENCE MONTHLY 105 Apnit, 1929

| a STRICTLY LLQCAL STATION | © mie | ay ithon “FOLKS, this is station F-U-N-N. <i | — Before playing our next number t with aa we want to tell you we use Ever- tan = hy eady Layerbilt ‘B’ Batteries ’cause ad to. they last longer. They’ve got lay- rar | ers in ’em like a cake. When mi .; Mother bakes a cake we eat it : & right up quick, and it doesn’t last at all, but you can’t eat an Ever- eady Layerbilt and a radio set can’t eat it up either. That’s why it lasts so long. Father says he saves a lot of money by buying Eveready Layerbilts. You will now be entertained by the orchestra of the Great American Music, Social and Athletic Club playing the song, ‘That’s my battery new.’ ” NATIONAL CARBON CO., INC. New York fijae San Francisco Unit of Union Carbide and Carbon Corporation

PP ER

This is the original Eveready Layerbilt No. 486—the LARGE SIZE for heavy duty — list price, $4.25, only 25 cents more than the Eveready cylindrical cell b th ize, No. 770. Th TUESDAY NIGHT IS EVEREADY HOUR NIGHT oycr,0! Us trie bile is the Medium

le Size No. 485—list price, $2.95, only 20 a East of the Rockies—9 P. M. Eastern Standard Time, through WEAF and associ- jaro pe ot em, Peper d “ oe » Anse P ated N. B. C. stations. On the Pacific Coast—6 P. M. Pacific Standard Time, *#2e cylindrical cell “B” battery No. 772. H through N. B. C. Pacific Coast network. Lay erbilt construction is a patente d 7 Eveready feature. Only Eveready SEE AND HEAR THE NEW EVEREADY RADIO SETS makes Layerbilt Batteries. tS} This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8.

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106 POPULAR SCIENCE MONTHLY APRIL, Igy Landing Gear for Model Plandl By Vincent L. JOHNSTONE = iy ee _ ' Y sam F YOU use the landing gear described Re) in this article with a model built Waki : according to the plans in the March WAKO we issue for the world’s record seaplane of LPS nscheaws Tudor Morris, you will find yourself in a good position to win prizes in any model airplane contest. , , ON: & “a What would be better for an R.O.G. | -- se i er MAKE DOLLARS (rise-off- ground) contest CN EY ee wa? OUT OF DENTS plane than the 124-minute Piomb Dollies are Morris model with this landing gear instead of the of universal shapes floats? The extreme light to take any weight and the simplicity of af fender curve. both the construction and tae | Heat-treated | | the attachment of this gear a ae ae _ to proper should make your model wy hardness to the envy of all your friends. Fig. 1. With landing gear substituted for floats, the Morris pasheteavere You will need only a few world’s record seaplane can be used as a rise-off-ground model, ‘ materials: 1 pce. bamboo, 12 Dammenering, in. long, several yards of heavy silk and can be made considerably smalle Pliomb thread (size D buttonhole twist pre- and lighter in weight than would be poss. Fender ferred) ; 1 pe. balsa veneer, 7; by 34 by 144 __ ble if you used the weak and brittle inne in.; 4 washers; 2 common pins; and a_ part of the pole. Hammers; small piece of No. 6 (.016 in. dia.) music The two wheels are made by holding a the time tested wire. small coin—a penny, nickel, or dime~ patterns of skill- This type of front landing gear, which against the balsa veneer and cutting around with a knife or razor blade. Ip Ta cate the center of the wheels as accurately f as possible, and with an ambroid type of cement fasten a washer ex. | actly in the center of one side of each wheel. Allow the cement to dry thor. oughly without disturbing it, which is the secret of using this kind of cement successfully. Note that you should fasten the washer only on one side of the wheel at first. The reason is that it is much easier to make the wheel run true if the first washer is steel and heat- solidly cemented before you locate and treated to with- fasten the second washer. You can usea stand tremen- || js shown in Figs. 1, 2, and 3, was used on . Common pin as an axle to rotate the whed dous strain the machine that holds the world’s twin pred for wobble. By shifting the without pusher R.O.G. distance record. There is me wr a — A IS easy LHe the bending. another very good and more recent type We! run absolutely true. en the ce- ful fender men. Hand-Forged from finest steel and heat- treated so that the faces will not dent with usage. Plomb Fender and Body Spoons; a necessity for quick work. Hand-forged from one piece of Fig. 2. Because of its unusual power, this model rises quickly, illustrated in Fig. 5, but it requires more ™€nt on the second washer is dry, youcan care in mounting on the A-frame and is consider the wheel as done, unless you wish given mainly for advanced model makers, *° take some fine sandpaper and slightly to whom the drawings will be self-ex- Tound the edge of the rim to streamline it, planatory. To make it (Continued on page 127) For the landing gear shown in Fig. 8, you will need to make two pieces of bam- Sq PONT TO Ft CUTTING OUT WHEELS boo 10 in. long and 3; by % in. in cross ey \ section, which should be oval. Then you will need to make the crosspiece, which ger, is bamboo 4; by 7}; by 12 in. Se Remember that in reducing bamboo to size it is advisable to split the wide stock ation Mechanics, Plumber, Steamfit- in the center each time. Even if it is as OVAL BAMBOO ter, Machinists and other artisans. much as an inch wide, for example, split > Sold by Automotive Jobbers, Hard- it in the center; then split one of the 4- 4- HOOKS Plomb Tools made for Auto and Avi- ware Dealers and Plumbing Supply in. pieces into two \-in. pieces, and so *6 WIRE WASHERS Houses where Display Boards may on, until you have obtained the exact (1 ON | he seen. size you want or slightly larger. You can | | ROUND EDGES Send for literature stating whether for easily scrape and sandpaper the piece to ~“*“FOR STREAMLINE Plumbing, Garage or General Use the desired shape in cross section. STANDARD FRONT CHASS/S_CONSTRUCTION PLOMB TOOL COMPANY Use only the part of the bamboo next -~ ; P ° ig. 3. Details of the front landing gear and 2209 Santa Fe Avenue, Los Angeles to the shiny or outer surface of the pole, now the heier wend wheels are cut Uae or 1146 West Lake Street, Chicago as this part of the wood is much tougher mounted. Note the use of thread braces. @ This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8.

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dime—| Cutting | le. Le urately | type of | her ex. | of one | Allow | ~ thor. | urbing | ret of | ement | washer | t. The : make | sher is e and | use a wheel ng the e the he ce- yu Can 1 Wish ightly ine it. e 127) ApRrIL, 1929 POPULAR SCIENCE MONTHLY This Machine Develops Corona Tests for High Tension Cable Used on Modern H. C. Engines What is Corona? Corona is an electrical phenomenon present on the outside of all high voltage conductors. It is accompanied by the release of free ozone due to the electro-chemical breaking-down of the surrounding air. Corona can be seen in the dark as a purple glow surrounding the conductor, and can be readily identified by its pungent odor. How Does Corona Affect Spark Plug Wires? Ozone is a vital enemy of rubber and causes it to deteriorate rapidly by producing invisible cracks, and eventually opening the insulation through to the copper conductor. The electrical leakage caused by even this slight deterioration seriously affects the power of the motor. Why is Corona a New Factor? A few years ago engine compressions ranged from fifty to sixty pounds per cubic inch and required five or six thousand volts for satisfactory ignition. Modern high-speed, high-compression engines require in some instances as high as 18,000 volts for satisfactory ignition, and there are extremely high speeds that render any leakage whatever of vital importance. How Can Corona Effects Be Minimized? Although corona is always present in high volt- age circuit, its evil effects can be minimized by sealing the rubber insulation against it. This is done in Packard Lac-kard Cable by multiple coats of a special pyroxylin lacquer with which the braided covering is protected. As long as this seal is kept intact, the rubber is protected from the deteriorating effects of the ozone. What is Packard Lae-kard Cable? Packard Lac-kard Cable is the latest develop- ment from the research laboratories of The Packard Electric Company. It is rubber-insulated cable of the highest quality, protected by a stout braid which is, in turn, treated with multiple coats of pyroxylin lacquer which hermeticall seal the rubber insulation from the attac of ozone. It is the last word in high tension ignition cable. What are Packard Ignition Cable Sets? Packard Ignition Cable Sets consist of the differ- ent leads from the distributor to the spark plugs and from the coil to the distributor, a u with universal terminals attached to the prt plug end of the cable at the factory. Distributor terminals as well as distributor protectors are included in the handsome purple and yellow carton which is displayed on the shelves of leading automotive pe and jobbers in the United States and Canada. SEND FOR STORY OF CORONA, THE POWER THIEF 4 . *s Name Car, Year and Model_____- 107 Slee eesceaac es ssaSBSSSSSSSSAASSSSSSSSSSSSSSSSSSSSSSHSSSSHSSHSESS SHESSSSSSHSSHSSSSSESSSSSSSESESSEEEEESSHSSESEEEEEEEEESEESEEEESESEEES >; PACKARD LAC-KARD IGNITION CABLE is standard equipment on a very large percentage of modern cars of the better class. For further information, fill out and mail the coupon. From $2.00 to $4.75 FOR ALL CARS. State City ONLY ON GOODS OF HONEST VALUE

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108 Champion X—For Model T Fords— Packed in Red Box— 60c. Champions— For all other cars, including Model A Ford, and trucks, tractors and station- ary engines—75c. A New Improved CHAMPION for Every Type of Engine Desicnep and made to meet the stresses of the most advanced modern engines, the new im- proved Champion is far in ad- vance of the Champion Spark Plug of even six months ago. The new and exclusive silli- manite insulator is as vast an improvement over all previous insulators as the original silli- manite over percelain. It has been specifically designed to meet all conditions of the most advanced engineering. A remark- able new sillimanite glaze re- mains practically impervious to carbon and oily deposits. The advanced new solid copper gasket seal remains absolutely gas-tight against the much high- er compression of today’s engine. The special analysis electrodes have been greatly improved to resist pitting and burning. Remember—it is a genuine econ- omy to install new Champions every 10,000 miles. A complete new set of improved Champions installed in your car will show ac- tual savings in gas and oil which will more than offset their cost. CHAMPION Spark Plugs Toledo, Ohio » Windsor, Ontario @ This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. POPULAR SCIENCE MONTHLY Blueprints for Your Home Workshop UR blueprints can be obtained for 25 cents a sheet. In some cases there are two or three sheets to one subject. The blueprints are complete in them- selves, but if you wish the corresponding back issue of the magazine in which the project was described in detail, it can be had for 25 cents additional so long as copies are available. Other subjects be- sides those below are to be had; send a stamped envelope for the complete list. Popular Science Monthly, 250 Fourth Avenue, New York Send me the blueprint, or blueprints, I have underlined below, for which I inclose........ Pavegeksiccenet EO Described No Title inIssuesof Price 2. Smoking Cabinet *Mar., °22 25c 5. Kitchen Cabinet *“May, °’22 25c 15. Workshop Bench *Jon., *23 25c 27. Kitchen-Cabinet Table Oct., 23 25c 30. Tool Cabinet, etc. *Jan., °24 25c 31. Sewing Cabinets Feb., "24 25c 37. Simplified Bookcase Dec., "24 25c 43. Four-Tube Receiver (battery operated) *July, °25 25c 44-45. Pirate Ship Model *Feb., °26 50c 46-47. Galleon Ship Model May, ‘°'26 50c 48. Sailing Yacht Model *July, °26 25c 50. Airplane Model (Rise-off- ground tractor, 36 in.) ‘*Sept., °26 25c 51-52-53. Clipper Model, Sovereign of the Seas Oct... Ss 75c 54. Five-Tube Radio Set *Oct., 26 25c¢ 55. Five-Tube Set—Details ‘*Oct., 26 25c 56. Bird and Animal Toys Dec., °26 25c 57-58-59. Constitution Ship Model (‘‘Old Ironsides”’) *Jan., 27 75¢ 60. Welsh Dresser ar., °27 25c 61-62. Viking Ship Model Apr., ’27 50c 63-64. Toy Motor Boat, 29 in. long hull ay, °27 50c 65. Six Simple Block Puzzles June, ’27 25c 66. Ship-Model Weather Vane Aug., °27 25c 67. Toy Model of Lindbergh’s New York-to-Paris Plane Aug., ’27 25c¢ 68. Magazine-Rack Table and Book-Trough Table Sept., °27 25c 69. Flying Model (3 ft.) of Lindbergh’s Monoplane *Oct., °27 25c 70. Console Radio Cabinet Nov., °27 25c 71. Console Cabinet—Details Nov., ’27 25c 72. Doll’s House “ee., "ST 25c 73. Doll’s House Furniture ‘*Dec., ’27 25c 74-75-76. Santa Maria Ship Model, 18 in. long hull ‘*Dec., ’27 75¢ 77. Simple Pier Cabinet and Decorative Wall Shelves Jan., ’28 25c 78. Simple Treasure Chests Feb., °28 25c 79. Electric Radio Set Feb., ’28 25c 80. High Power Unit for Elec- tric Radio Set Mar., ’28 25c 81. Low Power Unit for Elec- tric Radio Set *Apr., ’28 25c 82. Simple Single-Stick Air- plane Model (30-in.) Mar., ’28 25c 83-8485. May flower Model Apr., ‘28 75c 86. Racing Airplane Model (35-in. twin-pusher type) May, ‘28 25c 87. Seaplane Model (30-in.) June, ’28 25c 88. Simple Modernistic Stand; Modernistic Bookcase Aug., °’28 25c 89-90. Bremen Scale Flying Model (3-ft.) Aug., °28 50c 91. Modern Folding Screens Sept., ’28 25c 92. Simple Baltimore Clip Ship Model (8 in. lon Sept., ’28 25c 93. Three Modern Lamps Oct., ’28 25c 94-95-96. Mississippi Steam- boat Model ov., °28 75c¢ 97, Modern Electric Radio Set in One-Tube Form Nov., ’28 25c 98. Modern Electric Radio Set in Two-Tube Form Dec., °28 25c 99. Modern Electric Radio + Set in Four-Tube Form Jan., ’29 25c¢ 100. Modernistic Book Ends, Book Shelf, Low Stand Dec., ’28 25c 101. Toy Fire Engine, Sprin- kler, Truck, Tractor Dec., °’28 25c 102. Morris Seaplane Model Mar., °29 25c 103. One-Tube Battery.Radio Set (Old No. 41 revised to Mar., ’29) 25c Magazine only out of print. es to oo Non “1s it level? em - it plumb) . Stanley Aluminum Levels are fitted with six proved glasses, No matter how you pick up the tool, one of these glasses is al- ways visible—instantly avail- able to level or to plumb. Made of aluminum, these levels combine light weight and great strength and will not rust or warp. The tops and bottoms are milled and ground to insure perfectly parallel surfaces. Heavy glass covers protect the openings for both level and plumb glasses, prevent- ing damage to the glasses and keeping out dirt. Complete description of Stanley Aluminum Levels is given in the Stanley Tool Catalog No. 34e. Send for a copy of this catalog show- ing the complete line. The Stanley Rule and Level Plant, New Britain, Conn. STANLEY TOOLS The Choice of Most Carpenters April

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Aprn, 19% ses. you one al. ‘ai 4 nb, ese ght vill are ire ect vel nt- ses April, 1929 ‘lo-day even the edge of the crowd POPULAR SCIENCE MONTHLY Tamer pia ie | & a ft , A few hundreds heard Lincoln T present-day inaugurations of Pres- idents of the United States, every- body in the vast crowd assembled at Washington is able to hear every word of the ceremony. A Western Electric Public Address System, with its loud- speaking horns above the speaker's stand and at strategic points in the crowd, makes this possible. This apparatus amplifies sound and distributes it to all parts of a city park Of square or an indoor auditorium. In convention halls of hotels, it brings the speaker’s voice loud and clear to people in the rear seats. The Public Address System has a growing use in hotels, in amusement parks, in hospitals, where music of other entertainment can thereby be dis- tributed from a single source to any number of places or rooms. The equip- ment is adapted to a wide range of 109 Unlimited thousands now bear presidents requirements ... A product of the tele- phone art, the Public Address System is electrically and mechanically depend- able. It is made by Western Electric and sold by Graybar Electric—two names that mean quality and service in things electrical. Western Elecfric PUBLIC ADDRESS SYSTEMS Distributed by GRAYBAR Electric Company

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110 heen applies lo ’ Your PAINTING PROBLEM HATEVER you paint —automobiles or baby carriages, buildings or bric-a- brac—spray painting will do a better job at lower cost. 7 A Brunner Spray Gun is from 3 to 6 times faster than the hand brush. It insures complete coverage and uniform finish; it reaches the inac- cessible places and can be efficiently operated by semi-skilled labor. Brunner Equipment Insures Results Beauty and durability in paint and lacquer finishes depend upon your equipment. Brunner equipment incorporates many proven features of design and construction perfected thru nearly a quar- ter century of Air Compressor and Pneumatic Appliance de- velopment. Model 300 Gun Our Industrial Department is at your service. Write for full par- ticulars and for interesting booklet on Spray Painting and Spray Paint- ing Equipment. BRUNNER MBG. CO. Dept. P. S. UTICA, N.Y. Model 721 Portable Outfit SPRAY PAINT EQUIPMENT BRUNNER POPULAR SCIENCE MONTHLY Metal Fastenings for Woodwork ARDWOOD dowels may be used in different ways. For some purposes, like reinforcing a glued joint, there is no | adequate substitute; but for other pur- poses there are metal pins and screws that | are more efficient than the wood dowel. These may be bought in many ordinary | , hardware stores or ordered from the cata- | logue of a large hardware dealer. The lengthening of a wooden rod by | means of a butt joint may be done easily, as shown in Fig. 1, by the use of a dowel screw. The joint is stronger than if a wooden dowel were used. One end of the screw may be turned into piece A with pliers, and piece B then is turned until the previously fitted ends are in per- fect contact. This requires the accurate locating or centering of the dowel, or of the hole C, which should be no larger than =o DOWEL sonnel C. i pe Mae ty +e Ag 4, 4 AA Me, i airy bred rt: Looe. » naaetael é 7 STEEL “PINS CENTERING A XY GAGE f ah 17. Exe 3 : Ani ve | Prony Pay! RBED ~ SOCKET_ BA FIG. 1 = A 4 °F [pa ba Pa Oe Pa be) L FIG. 3 Methods of making joints in woodwork with dowel screws and three types of steel pins. the unthreaded central part of the dowel screw. The holes may be centered by using a gage from four sides of the joint end of each rod as indicated, and marked definitely with a center punch to permit the exact centering of the drill. In certain cases the joint will be stronger if the screw dowel is placed near the edge where the greater tensile strain occurs, as at D. The steel dowel pins in Fig. 2 may be used as a guide in bringing two edges to- gether. Center the holes accurately by placing the pieces together and mark A. then B, following with gage mark C and center punch mark D, as indicated. Bore the holes in each piece the size of the smaller end of the pin at E, for the pin then will be held by the pressure of the wood at F. Drive the pin into F, perhaps using glue sparingly, but do not use glue in hole E if the joint is to be opened again. The barbed steel dowel pin in Fig. 3 may be centered by the same method and a hole bored in each piece of a size (A) that will allow a close push fit for the dowel. Glue may be used sparingly. The steel pin and socket in Fig. 4 are especially valuable where pieces of wood are to be repeatedly pushed together and separated.—Davip WEBSTER. Byrd Expedition Takes AMERICAN SCREWS W/HEN inferior products may mean loss of life or failure to succeed, no chances are taken. America’s greatest explorer, therefore, is equipped with the best materials this country can produce —among them are American Screw Company Wood Screws. American Screws are recog nized by Navy officials to be the best for both metal and wooden construction. They are easy to insert and hold tight under the most trying circum- stances of strain and weather. — ss O3Liny Merion %, é WOOD MACHINE STOVE SCREWS SCREWS BOLTS AMERICAN SCREW CO PROVIDENCE , R.1.,U.S.A Western Depot: 225 West Randolph St.. Chicago, Ill. “Put It Together With Screws” on eae TIRE BOLTS Pe

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ducts fe or ances >atest ipped this nong crew *COg: o be and y are tight um- her. IRE LTS Co A. 9 POPULAR SCIENCE MONTHLY — The same Every kind of woodworking operation Fast, Accurate OuTrT and profitable commercial work including PLANER, SAW, LATHE AndELECTRIC MOTOR, And MANY USEFUL ATTACHMENTS COMPLETE) Nake everything out of wood ae hanne mee with the famous SANDING, BUFFING, GRINDING, ATTACH- MENTS Amazing low price includes everything . This complete all electric shop costs less than most other outfits and gives you an excellent value. You can prove it EASY TERMS at home by actually using the Workace in every kind of —_Our termsare all in your foves, a . ° . . new and revolutionary method woodworking operation, making furniture or other useful sepdaaan, Wane annine mae and decorative things for your own home and to sell at a = Workace Shop out of the profits if i oe it makes . A small down handsome profit. The Workace is fast, accurate and easy ccmaan Sols, Saw Cae to work with. Planing, sawing, turning, drilling, grinding, complete and ready to set up for sanding or buffing—you save time on every operation, do craton a a, all you'll better, cleaner work, too. scarcely miss the money . There’s ample power, strength and capacity in The — coupon now—today— Workace Woodworker to do any job quickly and econom- details and a oumalidle Seacaty- ically . . . mitering, tapering, rabbeting, beveling, slot- 0m by return mail: ting, cross-cutting, ripping—anything. Every unit works from the G. E. motor. All parts are sturdy and well fash- ioned. The regular Wallace UN- QUALIFIED GUARANTEEassures replacement of defective parts for one ycar. This is a simple straight-forward offer—no exaggeration, no red tape— just plain facts that you yourself can prove. If you want to make wood- working your real hobby—or a real source of income—send this coupon i J. D. Wallace & Company, { Chicago, Illinois. away. ° for all details of this unusual prop- Workace 14” Bandsaw Kind of Business................. Speedy, accurate, osition. caaaea, Te $75 | pe Peer rer rrr eer eee | GOR: iitivusccasdiuseineiedae INCLUDES ALL THIS: 4” Planer 8” Circular Saw 6” x 36” Lathe 8” Disc Sander 6” Buffing Wheel 5” Emery Grinder \,” Drill Chuck 4H. P. G. E. Motor, 110-Volt, A. C., 60 cycle Endless V. Belt, two 4” and one 2%” V Belt Pulleys, Cast Iron Sub Base and 10 ft. Cable with separable Plug. The Planer and Circu- lar Saws are each com- plete units and may be purchased separately at the correspondingly low price of 5.00 each, SEND TODAY f------------ Wilcox St. and California Ave., Get outfit right away I That Workace Electric Woodworker sure looks good to me. Jj i I want to know ALL about it, including your easy terms, right Tee eee eee eee eee eee) Tete eee eee eee eee eee) eee eee eee eee eee eee SRB nc © This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8.

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112 SIMONDS CIRCULAR SAWS for the ~ home workshop Cut Easier Stay Sharp Longer W HEN you use Simonds Circu- lar Saws in your home work- shop, you get the same depend- able service—the same perfection of workmanship—that characterizes the Simonds Saws used by leading industrial plantsall overthecountry. Because Simonds Small Circular Saws are made from specially tem- pered steel they cut more smoothly and keep their cutting edges longer than any other saw you can buy. They are fast cutting and accurate. The teeth are uniform and perfectly aligned. Simonds Circalar Saws are regularly supplied with several leading makes of portable rigs and home outfits. For the satisfaction that comes from using cutting tools of the highest quality, insist on Simonds Saws. The name Simonds is your guarantee of perfect workmanship. Simonds Small Circular Saws are made in sizes to fit all portable and other types of electric sawing outfits. If your dealer can’t supply you, we'll gladly forward you any of the Circular Saws described be- low upon receipt of listed price. When ordering state size of arbor hole. 6 inch, $3.30 10 inch, $5.60 8 “ 4.40 12 “ 7.00 SIMONDS SAWS FILES KNIVES STEEL SIMONDS SAW AND STEEL CO. “The Saw Makers” Established 1832 FITCHBURG, MASS. Branch Offices and Service Shops in Principal Cities © This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. POPULAR SCIENCE MONTHLY Turning Large Work on a Small Lathe S THE owner of one of the popular | electric workshops with a capacity for turning wood about 9 in. in diameter, I was confronted with the problem of turning a piece to a diameter of 101 in. I found that I could easily turn this piece or, indeed, one as large as 11 in. by placing the faceplate on the left instead of the right side of the motor. My workshop has a two-shaft motor of sturdy design so that by taking off the circular saw and attaching the tool sup- port base to the T-slot as shown, I was Faceplate on left end of a small motorized home workshop for turning a 1014-in. disk. able to accomplish the job quickly with- out devising any awkward makeshift ar- rangement. One caution should be observed: The stock should be cut a little larger than the finished diameter on the scroll saw before it is fastened to the faceplate, and the faceplate must be fastened to the exact center of the stock. This will prevent excessive vibration and the possibility that the stock might be torn from the faceplate. It is also important that the faceplate be fastened securely with four heavy screws so that there will be no danger of its loosening during the turning opera- tion.—JosEPH LuKow!Tz. Novel Way to Bend Bamboo for Model aan HAT readers in far corners of the world are building PopuLar Science MontTHLY airplane models is indicated by many letters which have been received, among them the follow- ing, from J. P. Smith, of Christchurch, New Zealand: “Some of your readers, when making model airplanes such as the Bremen, may have experienced difficulty in bending bamboo in the exact place required by ELECTRIC IRON Milift Using an electric iron to soften bamboo. * means of an ordinary candle flame. This difficulty may be easily overcome by using the ordinary domestic electric iron as illustrated. I found that very accurate bends could be made by this method, and had no scorchings or breakages.” APRIL, ly Do your figuring scientifically wil the RUXTON MULTI-Vipp Multiplies—Divides The new Executive Multi-V ider is made of light, durable Bakelite Outside metal parts all 14 karat gold- filled. Positive pencil action. Large eraser and lead chamber. Of lifetime durability. In hand. | m some gift box. AN engineer invented this jp strument. It can save hou for technical men, students, i, ventors, business men and sale, men—for anybody who has fig uring to do. Do you wish to multiply, & vide, get proportions or percem ages? Shift the magic scales the Multi-Vider—and the answer is before your eyes—as easy read as the time on a clock. With this aid, in a few seconds you ca calculate horse-power, man-hou costs, speeds, areas, formulae, re ductions, production and sale data—solve a host of problem you meet daily at shop, home or desk. And the Multi-Vider is there in your hand to write the answen down. It is also as fine an auto matic pencil as money can buy, Don’t waste time needlessly a day longer. Office or mechanical worker, student or business man, now utilize your time for cree tive purposes. Get your Multi ider now. The Multi-Vider is made with precision accuracy—like a fine watch. The pencil movement is the finest obtainable. The priced the new improved Executive gift model with gold-filled cap, point and clip is $10.00—no more than you might pay for a high-grade automatit pencil alone. The serviceable Junior model, with outside metal parts in heavy silver plate, is $5.00. If your dealer doesn’t haveit yet, just mail the convenient coupon below Introductory Offer RUXTON MULTI-VIDER CORPORATION, Dept. 01, 2452 Graybar Bldg., New York City Send me Multi-Vider Pencil with New Instruction Book let. I enclose $10.00 for each Executive Multi-Vider @ dered. ($5.00 for Junior model.) Pri bep ieee pirerfinng Name....... — FN ORI ee SI TOE TIT = pg | ERE AER |

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ted this jp save honun tudents, in n and salep rho has fig ultiply, & or percent c scales of the answer “a8 easy to ‘lock. Wit ds you can , man-houw rmulae, re and sale problem », home or r is there he answen € an auto r can buy, -dlessly a .echanical ness man, for cree ur Multi. nade with ke a fine yement is e price of utive gift ‘ap, point nore than jutomati¢ tion Book i-Vider @& youns men ambitious to become leaders in America’s newest industry — Aviation Fortunate young men! To have your futures paralleling that of a new giant industry offering you boundless opportunities. For this is the young man’s day. And aviation, still but an infant industry in spite of its present $100,000,000.00 proportions, is a young man’s business. The fu- ture of aviation is definitely tied up with your future because its development depends upon the young man trained to develop it. What Aviation Needs. And You! Aviation needs men with thorough, practical training to oper- ate the rapidly developing transcontinental air lines. It needs trained men to supervise operations and traffic. It needs men with a thorough knowledge of aviation to direct the develop- ment of this new business in financial circles, manufacturing plants and dozens of allied industries. A shortage of trained men now exists. Having a practical knowledge of aviation as given in Universal Aviation Schools, you are prepared to grow with the industry in any field it touches upon. Cana man with a spark of ambition overlook this opportunity? Universal Aviation Schools A Division of the Universal + ’ Aviation Corporation Operating air lines between the Twin Cities, Chicago, St. Louis, Kansas City, Omaha, Cleveland, Cincinnati and Louisville, carrying air mail and passengers. Meet Opportunity Half Way Prepare now for what the future may offer. Thorough training in all branches of aviation from its business and maintenance end to the actual flying of commercial aircraft, is now available through the Universal Aviation Schools. These schools have been established in a number of cities by the Universal Aviation Corporation, a $10,000,000.00 organization operating aircraft over 5,000 miles of airways a day, between the principal cities of the country. Realizing the need for thoroughly trained men, the Uni- versal Schools have been provided with the finest and latest equip- ment and the highest type of in- structors in the Nation. Universal training will put you where you want to be in aviation. How to Start We want to hear from young men with ambition, not curiosity seekers. Therefore, we ask you to send 25c for the book shown here, which tells what Universal training may mean to you. Full of helpful information on the growth of aviation. Beautifully illus- trated. Send for your copy today. Only latest type government licensed ships and transport pilots having hundreds of hours of training experience are employed for student instruction in Universal Aviation Schools. UNIVERSAL AVIATI 4 Suite 1046-1055, Boatmen’s Bank Bldg. St. Louis, Mo. Enclosed find 25c. Send me your book, “Aviation—What It Means to You.”

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114 5 Tool for Your a Bench Lathe Tey" ‘T is a wonderfully designed and con- structed little tool, capable of handling a wide range of work in = laboratories, repair shops, trade schools, i and home. Attachments can be had for all manner of work. ATTACHIIENT S Have you a copy of our Tool Hand Book? TURRET ATTACHMENT It is free—send for your copy. GOODELL-PRATT COMPANY FRET SAW ATTACHMENT —" \ -..-., 7 “IENT GREENFIELD, POPULAR SCIENCE MONTHLY Apri, 194 who have been following our Mississippi steamboat articles now have their models of the Buckeye State completely finished. There remains but the problem of mount- ing and placing it—a problem of interest to all who make ship models. The first thing to be considered is: Where is it to be kept so that it will appear to the best advantage and yet not be in the way? In a very small house there may not be a vacant table, stand, or mantelshelf on which to place it. In this case I suggest fastening a shelf to the wall and standing the model on short pedestals, as_ illus- trated in one of the photographs on this & MASS. Another way to mount the model is on a pair of turned pedestals like the one shown above. You Can Place It on Pedestals or in a Scenic Case By E. ArmitaGE McCann, Master Mariner ‘How to Display a Ship Model If You Have Built Our Mississippi Steamboat, Captain McCann painting on canvas a typical river scene against a sunset dye sky. The landscape was used later as the background in a scenic case. ANY of the ship model builders page, unless one can find a suitable niche or angle in the wall for a shelf to support a scenic case. Small as our model is, a scenic case, being somewhat large, would look clumsy projecting from a flat wall. If, however, the room is large enough to house a scenic case without its being obtrusive, the most picturesque method of mounting this type of model is to place it in one so that the model will appear as if in her everyday surroundings, steaming up the Mississippi or Ohio River. The first thing to do is to make the The original Buckeye State model displayed in a scenic case. case itself. I made mine 9 in. wide, 14 in. high, and 30 in. long. A wider and longer case would be better if there is sufficient space for it. Any well-seasoned hardwood or soft- wood will serve. If a substantial piece, say % in. thick, is used for the bottom piece, the rest can be very thin. A piece of fiber wall board will do for the back. For the water I obtained a piece of rippled green glass, 834 by 30 in., and cut a hole in it to re- (Continued on page 120) © This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. lena nmowket Wee wa eanosee

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Ap POPULAR SCIENCE MONTHLY 115 a id | Home Workshop Have you pride del | Chemistry | rr nership of fine tools? | Y Will Save Time in OW Pp € ut, ==-—- and Money se Bis. ANKEE” toolmakers served their apprenticeship long be- fore the art of cheapening was OST of us at some time or another amauta aa have picked up bargains in “all Their standard—now erro es. wool” men’s suits or other gar- is the utmost quality and efficiency ments at absurdly low prices. Later we that can be built into a tool; the have sometimes realized that the money utmost saving of time and labor for had been thrown ty | tg Soy in- the user of the tool! ‘lity to distinguis etween € com- “Yankee” Chuck ee ” . . Unbreak - katie or The average buyer of — Fh pero anmenng, Mapp a able herd bargains in this line makes no test of the | centering Ball OtUCT DTrace. 1S appeal 1s na : ceeds, fabrics, but the expert buyer for a whole- bearing. Any bit, who take pride in ownership o Stes clad. sale house will take nothing until the cag tone baat finer things ... appreciate precis- Ball bearing. have been subjected to a rigid scien- accurately. jon and finish in toolmaking... tific analysis in a chemical laboratory, by pronnouxwnning understand the long-run economy means of which the percentage of cotton | BXXSSeeexw of paying a little more for quality or other adulteration can be discovered. RRR and eficiency. top’ ic nsaeteelaceecentnageete: wader teers enone end | PSII 1s ieing bowght om sigh hymn : : ‘ who thought they did not n and the poe of eae — — HS) another bit sons And by men ee ak eae making sure they will never have standard tests are simple enough for the b h amateur to perform in his own home ° Se Duy another. © laboratory. If a finished piece of goods 1 No. 2100. Four sizes: 8-, 10-,12- and is to be analyzed, small bits for the work 3 14-inch. Price, 10-inchsweep, $8.20. can be cut from such places as the inside = le nich of the seams without damage. * le The burning test should be applied =] my ay " first. To do this, pull out an individual z welll yarn or thread and hold in the flame of a = t wall match until it ignites. Wool catches fire 3 ugh to with difficulty and_ burns with the . characteristic odor of burning hair. Cot- nethad ton and linen, upon the other hand, ignite Ree readily and burn with little odor. Since . m . a ma — ger contain one wool yarn sone ae Beg eon ae ternating with one or more cotton oe jeg : — threads, this test should be applied to ee en a x several fibers in both warp and woof. e the HE boiling lye test is more trouble- some but is the classic method for detecting, and determining the amount of, an adulteration of wool. It should be tried by the amateur following his match a experiment. The method is to count the | a Ar er nl number of yarns or threads in a small holds bit in square of the cloth and then immerse it — — for exactly ten minutes in a gently boil- Bit can’t loosen ing, five percent lye solution. If the aalandeadne Two-jaw Chuck tester lacks a balance for making up this et. Fits any Boldesse — solution by weight, he can make one of analy freely. ” Gonmena)e approximately the right strength by dis- solving one teaspoonful of strong lye in twenty teaspoonfuls of water. oe At the end of ten minutes, what is left 99 of the square of cloth is removed from the solution, washed, and the remaining = AN . 14 threads are counted. The woolen yarns “Yankee” an in the mixture will have been entirely | pss Extension e il dissolved, while cotton or linen threads No. 2150 TO @O g SS will be See. Wool is the only com- | 151, 181,218, 248, mon textile fiber dissolved by this treat- $2.25 to $2.40. a ment, so the analyst cannot go wrong. ____MAKE BETTER MECHAN Ics tom oe quoticnt ehtsined by dividing the NORTH BROS, MFG. CO., PHILADELPHIA, U.S. A. iece umber of rPaneeng ‘ threads by the Yes; I like to own fine tools, Send me “Yankee” Tool Book, illustrating Quick- : original _count, multiplied by one hun- Return Spiral Screw-drivers, Adjustable-tension Push Drills, Somers (11-inch) a dred, gives the percentage of threads Hand Drills, Ratchet Breast and Hand Drills, Removable-base Vises, Etc. por vm ae — in adulterating the Pe Ce Oe Bete) ae 20) | mixture.—W. H. Hammonp. “diitatih..nasennaosasaonceerinisisiiaasiapassmmesieaieaasan (oo © This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8.

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116 a are you choose high grade tools when you do work of a difficult and exacting nature. In the selection of tools, it is best to know something of the manu- facturer. Pexto Tools are the result of many years of fine tool making, and have earned an enviable reputation for fine quality, exact balance and lasting material. Look for the Pexto trade-mark when you buy. Among the numerous popular items in the Pexto Line are Braces, Bits, Chisels, Pliers, Hammers, Screw Drivers, Wrenches and Snips. Send for booklet “‘S’’ The Peck, Stow & Wilcox Co. Southington, Conn., U. S. A. POPULAR SCIENCE MONTHLY Mixing a Low-Cost Varnish Remover By R. C. STANLEY N THE first of my series of articles on repairing antique furniture, which be- gan in the December, 1927, issue, I gave a formula for making varnish remover. | Since that time I have done some ex- perimenting and wish to give readers the benefit of the results in the form of a recipe which modifies the previous one and reduces the cost considerably. Mix’ (cold) 14% pts. acetone, 214 pts. benzol, 4 pts. denatured alcohol, and 2 oz. paraflin wax shaved fine. All these liquids boil at a lower temperature than does water. Bring to a boil a sufficient quan- tity of water and remove it from the vicin- ity of the fire. Place in it the vessel con- taining the mixed ingredients. In a short time the shaved wax will melt. The wax is used to give a body to the remover, so it will stay where it is brushed on and will not evaporate too quickly. If the remover is placed in hot water a few minutes before starting to use it, the wax will melt; using the remover warm enough to keep the wax in liquid state gives a quicker and more thorough action. These ingredients evaporate very rapidly when hot, so should be kept covered when possible. PREVIOUS article mentioned several uses for vinegar. Here are others: Paint and varnish brushes which have become dry and stiff can be made pliable again by soaking them bristle deep in vinegar heated almost to the boiling point. A strong solution of vinegar and salt will remove nearly all stains, grease, and spots from wood. The same solution may be used to give brass, copper, and iron a tarnish, which, if protected by lacquer, will make a beautiful antique finish. Simply immerse the metal in the solution until it takes on the desired color. When repairing broken china, glass, pottery, or crockery, wash the edges thoroughly with hot vinegar before gluing or cementing them together. If aluminum or galvanized metals are to be painted, first. wash them with vinegar, just as you might wash painted woodwork with water. The paint will not ‘cale from the metal as it is apt to do when no precautions are taken. The vinegar, being an acid which is noninflammable and nonexplosive, is not dangerous to use. When a mild acid is required, it can be tried and if the desired result is not obtained, no harm has been done, as would be the case with many other acids. These are the concluding suggestions of Mr. Stanley. In his series on repair- ing old furniture he has placed at the disposal of POPULAR SCIENCE MONTHLY readers the information gained in a life- time’s experience in repairing and refin- ishing furniture. For readers who have missed any of the articles and may wish to refer to thein, the complete list is as follows: December, 1927; April, July, August, October, November, 1928; and January and February, 1929. You'll Never Know where the hole or crack was when you © fill it with Rutland Patching Plaster. Makes perfect patch and lasts as long as the wall it. self. So easy, too! Just mix with water and use. Anyone can do it. At all paint, wall-paper and hardware stores. Rutland Fire Clay Co., Rutland, Vermont. Rutland Patching Plaster Principle Gives Smooth Ripple-less Finish. Powerful Universal Motor. Runs off the Light Socket. THE TAKE; Sander is Five Times Faster than Tedious Hand-sanding. Remove the Labor and Keep the Profits. Fine for Bench Work or Floor Edges, Boats or metal lishing. Quickly Pays for Itself. Repeat Orders Prove it. Ask for Free Demonstration. THE PORTER-CABLE MACHINE COMPANY 2000 Salina Street Syracuse, N. Y. Thirteen- Poca Port- a... - Electric Belt Sander. Sands Flat or Curved Sur- face. Handles likea Plane. Belt A definite program for getting ahead financially will be found on page four of this issue. @ This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. arn 230 ~s = @& a eo omer es ofan emo m—eketeo kw -s oS — | gpk. ert ee DF i aga

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apni, 1929 a Turning Boxes and Bowls (Continued from page 80) ight colored wood 15¢ in. thick. ¢ ae ees can be had in the thicknesses uired, they may be glued up in one solid flack as shown in the photograph on this page. The block is then prepared and turned in the ysual manner. If this is not possible, the fol- lowing slower method is recommended : The lower part of the box may be built up by gluing iece of dark wood to the waste stock as ex- 0 ned above. When the glue is dry, it is feened down to 3% in. in thickness and made rfectly level and flat. The next layer of light 278 is glued in place and faced off, followed by the dark layer and then the final light layer. When the required layers, reduced to the prop- er thicknesses, have been glued together in this way, the stock is ready to be turned. The cover for the box is built up in the same man- ner. The first layer of light wood is 2 in. thick and is screwed directly to a faceplate. This is faced off and followed by a dark layer, this in turn by a light layer, and this by a dark layer. As the cover must be of exactly the same diameter as the lower part of the box, these two How layers of woods of different colors are glued together for making an inlaid box. parts are put together as shown in Fig. 5, smoothed, and sanded. The dead center is run into that part of the cover from which the knob isturned. This adds to the stability of the box during the final smoothing and sanding. The knob is the last part of the box to be turned. This is easily done while the whole box is mounted between centers as shown in Fig. 5. Enough material should be left on the knob when the cover is cut off so that the mark made by the dead center may be entirely cut away. In all inlay work it is well to remember not to have too violent a contrast between the inlay and the inlaid surface. If, for example, imita- tion ebony (ebonized wood) and maple are used for the jewel box, the maple should be stained a darker color such as amber, which resembles antique maple. After completing the trays and boxes, the woodworker who has followed this series of articles should be able to analyze and deter- mine for himself the best way to do any ordi- nary job in spindle and emit turning. The nut bowl, Fig. 6, is turned by the “glue- to-waste-stock’’ method as explained last month. The design may be modified so that a small circular block is left in the center similar to the one shown in Fig. 3 on page.81 of the POPULAR SCIENCE MONTHLY 117 Make this FREE 7-day test first to prove to yourself the supremacy of this unique shaving cream. Mail coupon GENTLEMEN: We have sold more shaving cream by telling men not to buy it, than many have sold who constantly urge its purchase. Instead we have urged “Don’t buy yet— first let us prove to you the merits of our case, at our expense.’? And that confidence, and the superiorities of our product have won 86% of the men who have made our test. The coupon is for your convenience. It brings a liberal tube—at our expense. Use it seven days. Then, if convinced of what we claim, you will want to buy. Many men who never clipped an advertising coupon before in their im are now the greatest boosters of Palmolive Shaving Cream. 5 unique advantages 1000 men were asked what they sought in a shaving preparation. With their specifica tions, our huge laboratories began. After 129 experiments, success came. These are the five things we achieved, all in one noteworthy shaving cream: 1: Multiplies itself in lather 250 times. 2: Softens the beard in one minute. 3: Maintains its creamy fullness for 10 min- utes on the face. 4: Strong bubbles hold the hairs erect for cutting. 5: Fine after-effects due to palm and olive content. Please make the test You may be happy with ee present shav- ing preparation, still find this one better. You risk nothing in trying. We take the chance. Sowon’tyou mail the coupon, please? March issue. In this case, however, the block ’ sanding. is not removed. Instead, small holes are bored | PALMOLIVE RADIO HOUR—_—‘ 7 iS) H A\ A E S FR E E s. Fine in it for receiving the nut picks when not in use. pone ne Say Ma ednesday night— H "Orders The fruit dish, Fig. 7, consists of two parts. | 8:30 to 9:30 p. m., central time: 7:30 ' and a can of Palmolive After Shaving Tale The base is turned between centers in the usual ~ = p.m. mountain time; 6:30 ; pena suas Pairing we VIPANY way. The top may be turned in the way the to/: p.m., Paci ic time—over station r imply insert your name an address and mail to “Pt. >, N.Y covers of the boxes were turned (see Fig. 4). Oe ee —— ! B -3030, Palmolive, 595 Fifth Ave., New York City. as to be chuc so that a hole may i Oe ae bored in its underside for the 3¢ by 114 in. Pn ay tay Rows : ahead tenon on the base. In gluing the parts, leave After Shaving Talc—especially for r rage the upper part in the chuck and center the | men. Try the sample we are sending ; lower part by running up the dead center. free with the tube of Shaving Cream. ; (Please print your name and address)

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118 coe 53922 J COMPLETE with : Compressor Unit Plug Into Any Light Socket Give You a New Standard of Workmanship RASP the pistol-grip of the New Agita- tor Type ELECTRIC SPRAYIT—and pull the trigger! No matter what your job is—or the finish that you use—you’re proud of the job it helps you do, quality workmanship, truly prokenional, speedy, economical. There’s a reason for the tremendous success of the New Agitator Type ELECTRIC SPRAYIT. The “fluid agitation” i is considered the greatest single improvement in spray painting equipment since its inception. Plug-in the New Agitator Type FLECTRIC SPRAYIT at the nearest light socket — and you're ready to go. The spray, either fan or round shape, starts or stops instantaneously. The pistol-trigger controls it, always at full pressure, in a flash. Handled by leading jobbers and dealers. If ou do not know where to buy the ew ‘ype ELECTRIC SPRAYIT, use coupon below Rent a Sprayit for Home Use For any paint job in the home, your dealer can now rentyouan ELECTRIC SPRAYIT at a nominal daily charge. Write for details of the new Sprayit Home Rental Plan. | THE ELECTRIC SPRAYIT CO.,Inc. 304 E. Colfax Ave., South Bend, Ind. CL] Send me the New Agitator Type ELECTRIC SPRAYIT at $39.50, f. 0. b. | oO Send details of New 0 Send complete Sprayit Home Rental Plan information only | Principal use for ELECTRIC SPRAYIT | Write Complete Name and Address Below POPULAR SCIENCE MONTHLY Dressing Up Photographs (Continued from page 92) mid-point between the right edge and the point B, and make another dot at D. Find the mid- point between B and the lower edge, marked EF. With a soft pencil draw very lightly the lines EF, DG, and FHC. The point H determines the position for the lower right-hand corner of the print. “After you have used this system a few times,” Jack went on, “you can quickly find the position of the print by making light dots without drawing lines which must later be erased. “The panel comes next,” he continued. “After fixing the final position of the print by making a fine pinhole at each corner, turn the mount over and draw lines on the back in such a way that a rectangle is formed larger than the space marked off by the pinholes by about 34 in. on the top and sides and 1 in. on the bottom. With a wet rag moisten the paper along one line. Then lay under the mount a piece of thin cardboard with a perfectly straight edge, so that the edge coincides with the line, the cardboard being inside the rectangle. [See one of the accompanying photographs.] Lay a ruler along the line and trace one side of the How the embossing is done by tooling the mount down over a strip of thin cardboard. panel with a blunt instrument, such as a but- tonhook or the handle-end of a crochet hook. Stop exactly at the intersecting lines. This treatment will bend the moist paper slightly over the edge of the cardboard. When this has been done for every line, a neat panel will have resulted. The depth of the panel is governed by the thickness of the cardboard. “NOW turn the mount over again. You can provide a thin black border about the print by using an ‘underlay’—a piece of black paper cut slightly larger than the print so as to form a band about an eighth inch wide all around. The print is fastened to the underlay and the underlay is attached to the large mount by means of a little high-grade paste or glue at each of the corners. Often only the two upper corners need be fastened, as the glass will hold the others in place. Instead of glue, you can use a good self-curing rubber cement painted over the entire back. This has the advantage of producing a perfectly flat mount without staining the print.” “What kind of frame is the best?’’ Henry asked. “That depends largely on your personal taste, as well as the color of the picture. I like a dark, even a black, frame for some prints; others look better in a light one. Some people prefer to have the color of the frame match the predominating color of the picture. Prob- ably the picture of Mary Ellen would look better in a delicate polychrome. “Now, just because I have described one compination of picture, underlay, mount, and frame is no reason why you cannot work out other pleasing schemes,”’ Jack added. “‘In fact, | if you have a number of pictures to frame, a slight variety is best. Some pictures may be mounted without an underlay, or with one tinted buff, blue, or some other color.” Henry’s first picture mounted according to Jack’s suggestions was declared a success by Mrs. Webster. Within a few weeks many of the attractive prints that had been lying in odd corners of the house had been tastefully framed and were doing duty as interesting decorations for the walls. APRIL, 19 | Seasoned Smokey Tips Sixteen Off 0) His Tobacco “Find” Is ready to tell the world a the one and only brand for him Below we have a letter from a pi whose crusading spirit has carried the he colors of Edgeworth right into the pj of sixteen of his friends. Our hats pa. Mr. Stahl for convincing his pipe-smg ‘a friends that Edgeworth was the only smoke in the world for them. 1721 Cleveland Ave, Norwood, Ohio . Oct. 8, 1928 Larus & Brother Company Richmond, Va. Gentlemen: In the past twenty years I have beens consistent smoker. I was always anxious to smoke a pipe, but no matter how often I tried I soon changed my mind. I haye tried all kinds of pipe tobacco but not ones was I satisfied with their taste. Just recently, however, I gave my pipe another trial. It was my luck to choose E lgeworth this time, with the results that I am still using it and will continue to do so. I only hope that you will continue to give that same mild high-grade quality in the future. I have started not less than sixteen smoking Edgeworth, and they are still using that same unequalled non-biting tobacco to this day. I can recommend Edgeworth tobacco to anybody who en- joys a cool, non-biting brand of tobacco, and as long as I enjoy same, you can rest assured that I am going to be a good ad., and many a pipe smoker will be asked to give it a fair trial, and they themselves can act as judges. I always give praise where praise is due. After I was convinced of the wonderful quality of Edgeworth, I could not help but tell you people the same as I have been telling and will in the future tell others. Hoping that you will continue with the same quality in Edgeworth, I am Very truly yours, (signed) Joseph J. Stahl Let Mr. Stahl cast out his fears. Edgeworth smoking tobacco has always been uniform in its quality, and always will be. Let w e= Personal: send you free helping of Edgeworth Ready ea mM wa A " oO Rubbed and my worth Plug Slice, for ii you to try. If you like ats these trial pipe-loads you'll like Edgeworth whenever you buy it for Edgeworth Toba co is always the same —tin in, tinout Simply write your name ani address to Lat us & Brother Company, 108 2ist Street, Richmond, Va Edgeworth Ready - Rubbel is sold in smal, pocket-size packages, in handsome po humidor tins and also in several handy it between sizes. Plug Slice Edgeworth 8 packed in thin slices, for pipe-smokers like to “rub up” their tobacco in the palm of the hand. On your radio—tune in on WRVA,Richmond,Va. —the Edgeworth Station. Wave Length 270 meters. A ned 1110 Kilocycles.—Special Fea- ig ture: The “Edgeworth Club” Hour every Wednes- day evening at nine o’clock,Eastern Standard Time. ee a ee

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ve beens 3 anxious Ow often - I have not onee my pipe 0 choose > results ntinue to continue © quality . Sixteen are still n-biting ommend who en- tobacco, can rest ood ad., sked to -mselves e is due. onderful ot help I have ure tell vith the Stahl odgeworth n uniform ‘Let w o hae sii Slice, for f you like i pe-loads, :dgeworth u_ buy it th. Tobae- the same n, tinout ply write lame ani s to Lar Brother ny, 108 treet, ond, Va eworth - Rubbel in small 1e pound yandy i worth is kers wh the palm ond, Va. th 270 ial Fea- V ednes- d Time. apni, 1929 Peis Sewing Table (Continued from page 78) i have this groove cut in the pieces eS have the faces of them jointed (planed true) at a mill. About six hand screws are needed to glue up this column properly. When the glue is dry, Jane the column square; then lay out the Ftagonal shape on each end, draw correspond- ing lines the length of the column, and plane off the corners to these lines. naga The base is built up of six pieces. Each is first squared, after which pieces K, L, and M are planed to form f urther octagons. These three pieces are nailed and glued together, forming Materials for Sewing Table No. MK. PaRT Pes. T. W. L. A Sides of box...... 2% 8 17% B Sides of box...... 2 % 8 124% C Bottom of box... 1 %- 1344 1744 D Cleatsattopofbox 2 3g % 18 E Cleatsattopofbox 2 3g % 138% F Slats for sides of eer 4 3% 3% 7% G Slats for sides of a RS ae 60 3% 1 73% Sarre A A 2 Demme. 2.0.5. 22 4 15 SSSA ee 1 % 434 434 SS eee 1 \% 5 5 | ae 11% 9 9 N ER ES nis te, aiden 1 38 ll ll vice oi ciccnne : A 10/4 104% ee a ee R Sides of tray... 2 WY 24 15% S Sides of tray..... 2% 2% 6% T Partitionfortray. 1 % 24% 15% U Partitionfortray. 4 4 2% 31 V Bottomfortray.. 1 4% 7% 1534 W Cleats for tray... 2 % %% 124% ONE. ....5.. 1% 19 Flathead screws iS ) ae 24 1% Butt hinges, brass 2 Q2 Q2 All dimensions are in inches. one solid piece. The remaining pieces N, 0, and P are rounded at the corners and nailed and glued together. A %-in. hole is bored through the center of the bases, and a larger hole must be made in the underside for a washer and nut. The four feet are glued and screwed to the underside of the lower base. The box, column, and bases then may be bolted securely together after short dowels have been placed between the upper and lower base, the upper base and col- umn, and the column and the box to keep these pieces in their proper position and prevent them from turning when the bolt is tightened. For the tray, which is simply glued and nailed together, 14-in. plywood is suitable. The tray rests and slides from side to side on two cleats screwed to the inside of the box. The top is made of two pieces, glued one on top of the other, but it may be of one solid piece or of 5-ply stock, either 34 or 1% in. thick. The plywood is least likely to warp, but the edges must be left square and either veneered or ag ples top is hinged to the rear edges of the x. If so desired, a small lock may be set into the front edge of the box. Preceding articles in this series de- scribed a stand and a bookcase (August, 1928), several modernistic screens (Sep- tember, 1928), three modernistic lamps (October, 1928), skyscraper book ends, a modernistic bookshelf, and a low stand (December, 1928), and a cabinet (January, 1929). Fer blueprints see Nos. 88, 91, 93, and 100, page 108. POPULAR SCIENCE MONTHLY 119 Their vacation fare bought this fine car AST YEAR the Lymans went to a summer resort on the train. This year the family invested their vacation on Used Car Sales 1 Every used car is conspicuously marked with its lowest price in plain figures, and that price, just as the price of our new cars, is rigidly maintained. 2 All Studebaker automobiles which are sold as CERTIFIED CARS have been properly reconditioned, and carry a 30-day guarantee for replacement of defective parts and free service on ad- justments. 3 Every purchaser of a used car may drive it for five days, and then, if not satisfied for any reason, turn it back and apply the money paid as a credit on the purchase of any other car in stock—new or used. (It is assumed that the car has not been damaged in the meantime.) © 1928 The Studebaker Corporation of America Piedge to the Public. railroad fare in a good Pledge-backed car and will drive through Canada on their vacation—as well as enjoy short trips many week ends. Hundreds of thousands ofauto- mobiles are being purchased this year by second owners! For the same price, these careful pur- chasers buy unused transporta- tion at a bargain price. Every car onthe street is a “used” car. Don’t let false pride prevent your family from enjoying a good car. Free Book Tells How Send the coupon below now for valuable free book, “Howto Judge a Used Car.” Experts who buy hundreds of cars for resale tell you in plain words and pictures whatto look forand whatto avoid. This free buyer’s guide may easily save you $200.00. Spend 2c fora stamp and mail this couponNOW! 130,000 people have saved money by mailing this coupon! | THE STUDEBAKER CORPORATION OF AMERICA Dept. 164, South Bend, Indiana Please send me my copy of your valuable | free booklet, “How to Judge a Used Car.” State STUDEBAKER. Builder of Chin pions ———__—_______.

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120

OE ee Certainty and Ease of Starting

A fh Never has outboard motor- ing witnessed so many and such radical improve- | ments as are embodied in the new Johnson SEa- Horses. They wholly revolutionize this sport and obsolete all previous outboard motors. The Release Charger, a. wonderful new invention, makes starting positive under all conditions. It cuts starting effort so dras- tically it can no longer be called an effort. The Underwater Exhaust eliminates all exhaust Automobile POPULAR SCIENCE MONTHLY

Sea-Horse 32 Four Cylinders noise and gases. The Rotary Valve in the SEa- Horse 32 and Sea-Horse 16makes possible higher power peaks than ever before. Write for catalog on these and other startling improvements. Six models, priced from $115 to $335, F.O. B., Wau- kegan. Sold on free trial and easy payment plan. JOHNSON MOTOR COMPANY 2581 Pershing Road, Waukegan, Ill. IN CANADA Canadian Johnson Motor Co., Ltd., Peterborough, Ontario Distributors for British Columbia, Hoffar’s Ltd., Vancouver, B. C. Johnson Outboard n—~<.Motors e WORLD’S LARGEST MANUFACTURER OF OUTBOARD MOTORS,

You ought to have this handy Parks in your shop. Compact,

complete machine de- ib angle. Base for saw and motor makes it port- signed like a big production outfit at 1/5 the cost. able. Makes 244’cut. % H. P. double exten- loor space required only 42x72 inches. Does any sion shaft motor. Complete ready to plug into kind of cabinet.or joinery work. Write for circular. any light socket. Send for free folder of Saw The Parks Woodworking Machine Co. Details, also Bench Lathes, Gonemte Work 1547 Knowlton St. Cincinnati Oh ties. ’ » Ohio Canadian Factory: 338 Notre Dame East, Montreal

Base 28" long by 8” wide Table top 16" by 12” Outfit includes necessary attachments to rip, crosscut, bevel, grind, mitre, groove, sand, mortise, tenon and polish. Table tilts to 45° 13 Inches High °

Shop and other Hardware apedialtia _ THE WILBAR CO., Inc. 2"9,£;,Ariz9ne St-

APRIL, 199

Displaying a Ship Model (Continued from page 114) the rudders and paddle wheel. The center }; of this hole should be 1 or 2 in. nearer the f than the back of the glass and about the _ amount forward of the middle. iy _ To cut the opening accurately is gt; job and requires patience. After cutting the outline, one has to start in the middle” : short cuts, break out a small hole, and cut and break off the rest, a small Piece at pag One can, however, get it ground rs if a glass company with the necessa: i ment can be found. 7 The glass is set in the case so that it slopes slightly to the front and its front edge will be barely below the edge of the molding that is to be placed on the front of the case. Dig oyt ceive the hull up to the water line, including line QUARTER ROUND PIECES OF woop hin Sa Hes YB

MOLDING ENLARGED SECTION How the case is assembled. Rippled glass, if obtainable, is used to represent water. The pedestals can be turned in various de- signs or made by cut- ting down old turnings. 2 the baseboard, if necessary, to admit the hull | to the right depth, so that the top of the glass | will be at the water line. Streak the wood under the glass with yellow and brown paint to give the appearance of flowing and slight} muddy water. When the model is set in the glass, some! lightly tinted cotton wool placed between it and the glass and about and behind the paddle wheel will give an appearance of foam and| hide the joint. If the glass is not obtainable, a somewhat similar effect can be had by carving the wood to a slight ripple (there would be no big waves) and then painting it to represent river water. | What color is river water? Well, the muddy Mississippi River can appear to be almost any color. If you look down into it, the color may be brown-yellow; if you look along it, witha) blue sky above, it will be blue; or if you look, as one usually does, partly down and _ partl along the water, then it will be a green with

| Build It With a Boice Workshop! , No matter what you want to build of wood, Boice-Crane can help you. He'll send you this heavy-duty Saw-Jointer- and-Lathe motorized workshop on easy monthly payments with an ironclad guarantee of satisfaction or money back. ; more or less yellow in it according to the angle and the depth of the water. At sunset it may] be gold or red. Take your choice.

© This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. ” il agi a UNIVERSAL HANDISAW, 15 x 17 in. tilting table; 9-in. saw cuts 244-in. stock; 7-in. LATHE, Rigid bed, 3 speeds; 40 in. C. to C.; 4-in. JOINT- ER, cuts 0 to % in. deep. Wide rabbet arm. Fence tilts 45 deg. both ways. Send 1N¢ for 80-page booklet filled with helpful information and describing this and six other workshops. Also 12 and 14-in. band saws, jig saws, Books of Designs and instructions. W. B. & J. E. Boice Pa tg et Toledo, Ohio

Next comes the background. ‘This is bes painted on prepared canvas with artists’ oil| colors. When the paint is dry, glue the canvas) firmly to a sheet of cardboard and then set it) in the case so as to stretch across the back ant) come to the front of the case at the sides. A) few small tacks along the edges will hold the| canvas in position. Note that the rear con of the case are first filled with half-round blocks! of wood. If water colors are preferred, the same scent can be painted with them on Bristol board of drawing paper. As for the scene to act as a background, any- thing that looks (Continued on page 121) i

Page 115

ie 3 t the hull ' the glass the wood | wn paint | d slightly | ASS, some etween it | he paddle | oam and omewhat | the wood | ig waves) | r water. | e muddy | most any | olor may t, with a een will the angle! t it may s is best} tists’ oil | e canvas en set it! yack and | ides. A! hold the; > Corne?s | d blocks | ne scene | yoard or nd, any-} nage 121) ) $$ ApRIL, 1929 Oe Displaying a Ship Model (Continued from page 120) ank of the Mississippi or Ohio River If one has but little skill with ints, an earth bank (levee) with blue sky Se will be quite typical of the lower ‘ aches; but if one can handle paints, a more slaborate piece of scenery will be attractive. My background is reasonably typical of the lower Ohio with a sunset sky above. The background should extend to the front of the case at the sides in one continuous view. Join the background to the water with some gesso or putty painted to represent the river bank. The sky should be continued on the underside of the top. One could paint the scene on the back of the case itself, but the other plan is, in the end, easier and more effective. like the b will serve. HE front of the case will need a glass. For this picture-frame or similar molding with a double rabbet is required (see the cross section on page 120). The inner rabbet is for the glass and the outer to set into the edges of the case. Cut the molding so that when the corners are mitered together, the outside edges of the re- sulting frame will coincide with the outside edges of the case. Fix in the glass, set the frame on the case, and keep it in position with some side hooks or a few small screws driven from the sides. Varnish, paint, or lacquer the outside. In the alternative method of mounting the model, short pedestals can be turned or, per- haps, cut from some old furniture turnings. They should have short dowels in their upper ends to enter holes in the hull. These supports do not have to be any particular size, shape, or color, but the less conspicuous they are, the better. Mine are antiqued gold. The chief object of the pedestals is to lift the model clear of what it stands on, so that one can see the whole vessel even over the edge of a shelf that is high enough to keep the model out of harm’s way. Now I must leave you. If you have had as much joy in making your model as I did from mine, you have had a great deal; and now you have something interesting to look at and very much worth while. Small Baltimore Clipper Model Is Easy to Make aa a a 4 Picturesque model built by Richard Heinze, of Brooklyn, N. Y., from Blueprint No. 92. IMPLEST of all Poputar Scrence Monta ty ship models to make is the rak- ish little Baltimore clipper illustrated above. The hull is 514 in. long and the entire model, including the’ base, is only 8 in., yet it makes a striking ornament on any desk, table, or mantelshelf. Full size drawings of the tiny ship, the sails of which are whittled from wood, are contained in our Blueprint No. 92 (see page 108). Ranking next to this model in simplicity are the pirate galley (Nos. 44 and 45) and the Viking ship (Nos. 61 and 62). POPULAR SCIENCE MONTHLY CASEY .JONES tells 121 (Mennen Salesman) Casey Jones, President of Curtiss Flying Service, is one of America’s foremost pilots. As chief pilot and operating man- r of the Curtiss Flying Service, “The t fying organization in the world,” he has done much to make aviation safe and practical. This photograph of 0 .% = rong tn taken at Curtiss - Y., just Sefore Casey hopped off for California. " “We flyers vote for cool heads and CooL SHAVES” Jim Henry—famous Mennen Salesman—is interviewing some famous users of Mennen Shaving Cream. His reports will be published frequently in this magazine. JIM HENRY: “Before you take off, Casey, I want to ask a question. What do you think of our new idea of Menthol-iced Shaving Cream?” CASEY JONES: “Say, a flying field is cer- tainly a good place to ask that question! A flyeris a crank on shaving and shaving cream. And there’s a good reason for it. Out in all kinds of weather—flying every day—sometimes in an open cock- pit where the wind hits you full in the face. Every morning my face feels grate- ful for the cooling, soothing feeling that I get from Mennen Menthol-iced and my whiskers come off without a yank. Mennen Menthol-iced gives me the cool- est, smoothest shave I’ve ever had. I’m for it.... every day.” Mennen Menthol-iced— The Young Man’s Shave! Modern — refreshing — unique — that’s the new Mennen Menthol-iced. Young menare using it—men who appre- ciate cooler, cleaner, smoother shaves. Jim Henry has talked with hundreds of men asking what they think of Menthol- iced. Here are some of the answers: An executive—“Mennen Menthol-iced certainly makes a difference in my shave! I can sense it in the smooth way my blade works; I can see it in the mir- ror; I can feel the difference through a whole business day.” A well known artist—*Particularly good for blue Mondays. I like the in- vigorating after-effect on my skin.” A famous doctor—“The soothing men- thol relaxes the facial nerves and pro- tects the skin. I recommend it highly.” Mennen Menthol-iced Shaving Cream is the newest member of the Mennen line—a modern team-mate for the reg- ular Mennen Shaving Cream. Both Mennen creams have dermutation—a three-way shaving improvement —ex- clusively Mennen’s. 1—it softens the beard, 2—it lubricates the razor blade, 3—it invigorates the skin. ... The proof is in a trial! Send the coupon. Also Mennen Skin Balm—the touch of luxury to a perfect shave, and Mennen Talcum for Men—the man’s r that does not show, Great after a bath! MENTHOL-ICED SHAVING CREAM Jim Henry’s treat—14 COOL shaves. JIM HENRY, The Mennen Company, Dept. P-1, Newark, N. J. All right, Jim! If Mennen Menthol- iced is as good as you and Casey Jones say it is, send me a FREE tube. And atrial tube of Skin Balm, too.

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Give your Oil Burner CLEAN OIL XPERIENCEshows that most oil burner troubles originate with dirty oil—oil containing for- eign matter which clogs orifices and valves, wears out pump parts and causes excess carbon deposits in process of combustion. Here—in just one word—is the an- swer to the dirty oil problem: Purolator. The Purolator Oil Filter, which is standard equipment on the leading oil burners, removes from the oil and holds the harm- ful dirt and for- eign matter that create most oil burner operation failures. This Oil Burner Purolator filters fuel oil before it reaches the vital parts of the oil burner. Purolator requires practically no attention—merely remove the dirt and wash or renew the filter ele- ment once a season, and your burner will be assured of clean oil all the time. [f your oil burner is not equippea with a Purolator it is a simplé matter to install one. For complete particulars, address Motor Improvements, Inc., 352 Frelinghuysen Avenue, Newark, PUROLATOR THE OIL FILTER POPULAR SCIENCE MONTHLY x} A NYA aX A good paint spray- ing outfit makes a : = pleasure of painting even wicker pieces. ANY handy men and amateur painters and decorators are ask- ing just how much of the paint- ing and decorating about the house and workshop can be done with spray guns of the hand pump, foot pump, or small motor-operated types. They wish to know also what methods are re- quired and if really first-class finishing can be done with this new tool. Perhaps answers to these questions by one who has done finishing with most of | these tools of various types, as well as | with the larger outfits employed by pro- fessional finishers on furniture and auto- mobiles, will be helpful. In the first place, it should be remem- bered that the spray gun is a tool and, like any other tool, calls for a certain amount of practice and knowledge of its use before the best results can be gained. There is more to it than putting in the material and starting the machine. It is not an automatic machine. To learn its effective use, however, is not difficult. The first step is to study carefully the manufacturer’s directions. Take it for granted that the manufacturers know more about their products than anyone else.’ The smaller types of spray guns oper- ated with air by hand or foot or by a small motor are capable of doing good work with sufficient speed on the surfaces for which they are designed—furniture, wicker chairs, radiators in homes, and all small articles such as picture frames. They are also useful for touching up auto- mobiles. With these guns difficult work, such as finishing radiators and wicker fur- niture, can be done in a fraction of the ”~ ory \ ames ARERR LER tf WOOK Wh Ty ¥ EAAYY' "y appa 3? ; How to Do Decorating with Paint Spray Guns By F. N. VANDERWALKER Na] time required by the most rapid brushing, After some experience, perfectly smooth finishes can be obtained with these tools on furniture and cabinetwork with lac. quer, paint, enamel, or varnish. The siz of the round or flat spray projected by such small spray guns is, however, too small to make them practically useful on large surfaces or for painting houses and barns. One finds many odd uses for sprayers. For instance, when removing kalsomine or wall paper it helps greatly to spray the surfaces with water. When it comes to the application of glue size coats to wall paper in preparation for varnishing them to make them waterproof, these guns are superior to the brush because with the latter there is a tendency for some of the colors to run under the brush, whereas the spray does not affect the colors. Varnish or lacquer coats on wall paper also can be applied with the small spray guns, espe cially in bathrooms and halls where the areas are not large. Shingle stains are easily applied with these guns and with fair speed even on the moderately large surfaces of garages and small houses. N OPERATING a sprayer successfully it is necessary to consider the material to be sprayed; that is, taking it for grant- ed that the surface has been made clean and fit to receive the finish. The mixing of the material is very im- portant. The color pigments of lacquer, enamel, and paint settle to the bottom of the can, and unless they are completely mixed into the liquid, the color will not be correct, the opaqueness or ability of the coating to (Continued on page 128) Apo orl cha al Ee ae Ml ol ed

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APRIL, 1yy Ith brushing, y smooth ese tools vith lac. The size ected by ver, too iseful on uses and prayers, ilsomine pray the omes to | to wall ng them yUNS are vith the e of the reas the Varnish » can be S, espe ere the ins are id with y large es. ssfully :aterial grant- e clean Ty im- vequer, tom of pletely ill not lity of ye 128) 4 Aprit, 1929 a ——— Decorating with Sprayers (Continued from page 122) This type of foot pump is a development of the familiar, useful hand spray gun. hide the surface will be less than you expect, and the material is sure to clog up the small portholes in the gun, making it necessary to clean them frequently. Therefore, pour most of the liquid off the lacquer, enamel, or paint, and break up the pigment thoroughly. Then add the liquid to it a little at a time as you mix. When you think the mixing is done, strain the material through cheesecloth tied over the top of a can, and you are likely to find some skins, grit, or lumps of pigment on the cloth. This straining also helps to mix the material better. Thick liquids like lacquer, enamel, and paint are more easily handled by the spray gun if thinned from ten to twenty-five percent with the proper thinning liquid. For lacquers, use only the special thinner provided for use with the same brand. For enamels, use turpentine; for varnishes, a very little turpentine; for shel- lac, alcohol. As a rule it is not necessary to thin stains at all. Thin liquids atomize more easily and with less air pressure than thick liquids. Thin coats dry more quickly; and while they do not hide the surface so well, more coats can be put on in less time because of the rapid drying of each coat. Thick lacquers are apt to run or sag, and thick paints are slow to dry. It is much better to apply two or three thin coats evenly dis- tributed. than to try to hide the surface in one thick coat. Handling the spray gun is the next consider- ation. Load the material cup on any siphon- feed style of gun (such as the hand pump, foot pump, and small motor types) only about two thirds full. Hold the gun as far as practical in a horizontal position and always exactly at right angles to the surface. Take particular care not to tip the gun to one side or the other and never turn it upside down. Work the pump or turn on the motor while holding the gun facing some surface of no account in order to try out the adjust- ment of the nozzle. Go at it cautiously at first and turn the nozzle-adjusting screw until a solid stream of material comes out. Then turn it in the opposite direction until the material is atomized and comes out in a solid, uniform spray, not in spatters. Having ob- tained this adjustment, set the nozzle in that position by backing up the locknut or using whatever device is provided on the gun to hold the adjustment constant. You are now (Continued on page 124) | | | POPULAR SCIENCE MONTHLY ‘THE manufacturer of your car probably equipped it at the factory with a Purolator Oil Filter —so that you could be sure of clean oil—efficient lubrication. When the motor starts the oil pump, the Purolator goes on the job. It filters the oil as it circulates through the lubrication system. Removes all the harmful grit, road dust and metal particles—foreign 'substances that would wear out the bearings, score the cylinder walls and damage the pistons. The Purolator filter element is built into an oil-tight metal case, thoroughly tested for leaks and seepage. This unit is called the “Purolator cartridge,” and is re- movable. When it contains all the dirt and grit that it will hold the filter simply quits functioning— goes off the job—and the oil con- tinues to circulate just as though | there were no Purolator on your car. This usually happens after about 8,000 miles. 123 “Ask Your Garage Man” To put the filter back in operation requires only a few minutes. Just remove the old metal housing and insert a new Purolator cartridge, containing a new, clean filter ele- ment. And your car rolls away for another eight thousand miles of clean oil—and the cheapest kind of motor insurance. If your force-feed oiling system isn’t protected with a Purolator, you can easily install one—ask your garage man, or write to MOTOR IMPROVEMENTS, INC. 352 Frelinghuysen Avenue Newark, N. J. (Licensed under Sweetland Patents) Be Sure to Re-Cartridge Your PUR THE OIL FILTE LATOR “ON YOUR MOTOR CAR EVERY 8,000 MILES

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124 > >. FREE: A week’s better shaves. Just mail the coupon below. Why delay. men. setting acquainted with small-bubble lather and a longer-lasting shave ? T costs nothing to make this comparison. After a seven- day trial, we feel certain you'll thank Colgate chemists for their many years of research. They’ve proceeded along nat- ural, common-sense lines, creating a moisture-laden lather ut- terly different from the ordinary air-filled lather. New friends are being won daily to Colgate’s, not by lurid claims, but by vastly superior shaves—smoother, closer shaves that last longer—keep you well-groomed from morning until midnight. Compare with ordinary lather We invite a critical comparison—your present lathering contrasted with the Colgate way. The minute you lather up with Colgate’s, two things hap- pen: 1.—The soap in the lather breaks up the oil film that covers each hair. 2.—Billions of tiny, moisture-laden bubbles seep down through your beard . . . crowd around each whisker . . . soak it soft with water. Instantly your beard gets moist and pliable . . . limp and lifeless . . . scientifically softened right down at the base . . . ready for your razor. Thousands of men, after various trials with ordinary lathers, have adopted Colgate’s as supreme. To prove its superiority, mail the coupon below. We will send also, a sample of After-Shave, a new lotion—refreshing, delightful . .« the perfect shave finale. COLGATE LATHER Colgate’s lather (greatly magnified) showing moisture contact with beard and minimum air. A common-sense prin- ciple scientifically authenticated and proved out by mil- lions of men. POPULAR SCIENCE MONTHLY _6_d dd dd dd dd dd dd dd ORDINARY LATHER Ordinary, big-bubble lather (greatly mag- nified). Note air- filled bubbles which can’tsoften thebeard sufficiently. Only water can do the job. Only small bubbles permit sufficient water. ** After-Shave.” COLGATE, Dept. B-1767, 595 Fifth Avenue, New York Please send me, FREE, the seven-day trial tube of Colgate’s Rapid Shave Cream; also a sample bottle of Apri, 1999 a Decorating with Sprayers (Continued from rage 123) ready to begin spraying. Keep the gun q\ ten inches from the surface, but never hold j still in one place. Once you start spray; ih gun must be kept moving at a slow and ste pace. Spraying, like brushing, is done by a ing movement. If you stop the movement f an instant while the spray is being proj > are apt to flood the surface with pain acquer, or whatever you are using; and then a run will occur at that point. In that event, have handy a camel’s-hair or soft brush, one or two inches wide, and use jt to smooth over the run. In the case of lacquer jt may be necessary to dip the brush in lacque thinner to dissolve the lacquer run long enough to let you smooth it out. If runs or spatters cannot be avoided by the adjustment you have, alter it. Possibly, you have on the gun a nozzle that is too Most guns are furnished with two or mop nozzles having holes of different sizes. The larger holes are for thick, heavy liquids; the smaller, for the thinner liquids. Until you are experienced, it is well to tun the surface down to a horizontal position as soon as you have finished coating it, especially with lacquer. Then, even if you have applied too much in one or two places, it will not rup, The rule is to apply a thin coat, evenly dis. tributed over the whole surface, and let it dry before the next coat is applied. It is better to use two or more thin coats than one thick coat. Thus you avoid runs, and the drying is faster. If you want to spray part of a surface and not all of it, mask the part not to be sprayed with wrapping paper, adhesive tape, or the gummed tape used in shipping departments There is also a special masking tape made for this purpose. Parts not to be coated also may be protected by a coating of vaseline or other grease, but you must be very careful not to get grease on the part to be finished or the lacquer, enamel, varnish, or paint will not stick. Having finished a job, pour the material out of the gun and put clear thinner into it and shoot it through to clean the screen and the smajl tube and nozzle of the gun. Empty it | again and put clean thinner in a second time| to make sure of leaving a clean tool for the next job. This is the second of two articles on spray guns by Mr. Vanderwalker, whoisa leading authority in the painting trade and the author of several standard books on painting and decorating. The first article, which appeared in the Feb- ruary issue, was on choosing a paint sprayer. Paraffin Seals Paint ‘Cans AINT, putty, furnace cement, and similar materials cannot be kept in open cans without hardening on the surface or deterior- ating. To preserve them from one job to another, I protect them from the air with a layer of paraffin wax. In the case of ordinary paint, I place the can or bucket on a piece of newspaper, mark around it with pencil, and cut out a circle of paper, which is then placed on top of the paint to keep the hot paraffin from running into the paint. Then I pour in melted wax to form a layer 4 in. thick. Paste, white lead, putty, and cement require no paper; the wax is poured directly on top of them. The wax, which can be used over and ovef again, is kept in an old paint bucket ready to be melted when needed. Great care must be (EERE LOE Ae SOE En Re a eT eS OP ET taken that it does not catch fire while being MEDS cnncuisditncendmmennecenneetetninntptipemneneneninnuenations melted.—JoHN R. DopcE. —_, + , a — —— and | for a ing § of tr shov is fa roun

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Apa, Igy =e POPULAR SCIENCE MONTHLY 125 —_ 1 —s "|| iacmtee | FOR SM More Closet Space | (Continued from page 86) | * gun ee 7 ever hold. by placing it in a notch, which is cut ina | and ray} tt up DY ir 4m. block B, screwed to the rail on | ‘and ate 4 by Oy esi he closet. and steady site side of the c —s may be placed near the top edge of | N by a head casing on the inside of a closet door as vement f aon in Fig. 4. ‘This is a handy place for S proj " pa 2 hats. It is especially useful in . down- | with pai = t for the men to hang their ats as | 3 and the Tanne Since this space is out of view, | Ww I LLI AM % a event, ja dow nails will serve instead of hooks. | | ort iS d use it ty NE place in closets that is usually idle is © -(j- F lacquer it Ove inside surface of door. This _— in | t to use by making a trousers rack ng enough age Fig. 3 and fastening it to the H EAT IN G cross rails of the door. The rack consists of a ded by the piece of wood 7% by 3 by 16 in. for the main Listed as Standard by Underuriters’ Laboratories sibly, too, piece, five pieces of }4-in. oe 24 in. long, ; too t jeces of wood 14 by 4% by 4 in. The _ ° “ . > OF more in dowel rods are placed through the main has made good with Popular Science Institute izes. The member so that the upper one is )4 in. from the quids; the top end and front edge, and the lower one 4 in. from the lower end and 2 in. from the front ell to tum edge. The other three dowel rods are placed on Osition as a line between the upper and lower ones. ; . especially | The rack is fastened to the door by the use ILLIAMS Dist-O-Matic ve applied of two blocks, one at each end at the back. A er a I not run, 1%-in. flathead wood screw is used to secure didn’t win the approval of venly dis. ach block to the rack, but 1-in. roundhead ‘ ‘ ind Tet it a used to fasten the blocks to the door. the Popular Science Ii stitute by t is better The trousers are folded once and slipped on- accident. It had to be go od to one thick to the rods. Ten pairs may be hung at one ‘ eae? drying is time. As the bottom rod is near the back of the make good with these scientific main member and each one above is a trifle rface and nearer the front, each a of trousers hangs experts. > sprayed early plumb. It adds to the neat appearance onne . . e, OF the af nd i if it is made of the same material Williams Dist-O-Matic pro- wt | Gaseeeed in the samo way as the door. vides genuine Williams Oil Heat made for _ The inside of a closet door also may be used also may for a rack for neckties. A suggestion for mak- for small homes and moderate or other ing such a rack is shown in Fig. 5. It consists ‘ sonia il not to|f | of two blocks 34 by 114 by 4 in., shaped as | incomes—the same Williams d or the shown. A piece of hardwood 14 by % by 16 in. a will not is fastened to the two main blocks with 34-in. warmth that has made Williams roundhead wood screws, and the rack is at- Oil-O-Matic so popular with erial out | tached to the rail of the door with 1-in. screws. o it and| more than 80,000 owners. ants el You Must ‘“‘Strike Gold”’ nd time | to Win This Game Thermostatically for the Controlled cles on Williams Dist-O-Matic is thrifty pate of fuel—unusually quiet—de- — pendable — entirely automatic Will: ‘ : ans—iet yourneares lillams 1e Feb- —turns itself on and off and : fe name h oe aint ° . aler analyze ur in . maintains steady, even health- 7 bl ' : ss eating : robiems today. ful temperatures without work y ans or worry. WILLIAMS OIL-O-MATIC similar You may buy Williams Dist- HEATING CORPOR ATION n cans x : ' 39 « ctestall Top, side, and end views and a sketch of the O-Matic on easy budget payment Bloomington, Illinois job to game in use. It should be painted brightly. with a , | bed THIS new game of prospector’s luck, the | 7 Approved by Popular Science Institute ce the player puts the ball on the upper platform, , mark spins the pan with one finger “* moderate - ircle of speed, and pushes the ball into the chute. If | é WI ¢¢ ‘ 9 of the the ball falls into the space marked “gold,” | HEAT FREE BOOKLET—“Heat without work or worry ng into it is a “strike,”’ and the player retires from the | without o form game a winner. If the ball rolls into any of the | work or See re: putty, other spaces, it is not a “strike,” and the | = aia : Williams Oil-O-Matic Heating Corporation vax is player waits his turn to try again. 4 Si a Bloomington, illinote <* co. he game continues until one player is left. | | Say __ Please send me, without obligation, your interesting booklet on d over He is allowed three final chances. If he strikes | & 5! dob Oi Heat, ‘’Heat Without Work or Worry. : ady to gold with one of these shots, he is as lucky as | Name ter eees ae ede eu ae we eects eeee . aie ee cme aegeeesceise ust be the rest, but if he fails he is the victim of | € ae oe SEER irae” being prospector’s luck and the loser. The sus- | AdGreS8. 565s nese ste e nese ee nesneceseres toe te wee-ae oat gees pense towards the last is what makes the | reer Oe oa ee __ 2 game amusing.—DoNaALp Ww. CLARK. | Jahed Ss Medinet died de ated Se ser erences * noe aeeeee © This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8.

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HELPERS for AUTOMOTIVE ELECTRICIANS PRICE, complete $5.25 Post Paid. Leatherette Roll folds to pocket size 5x4x3/8in MIDGET “Superrenches” —Seven of them. Real helpers on all automotive electrical work—mag- netos, generators, timers, wiring connections, etc. Delicate adjust- ments are made accurately and quickly. In close, cramped quarters, where an ordinary wrench won’t work, one of your Midgets will get in and do the job easily. Both openings, running from 7/32 to 4", are the same size in each “Superrench” but at different angles 15° and 75°. Where one head can- not operate, the other will. Midget “Superrenches” are forged from tough Chrome- Molybdenum steel, heat-treatedandchrome finished. Extremely light and thin, yet amaz- ingly strong. A Midget ‘‘Superrench”’ Set is invaluable to the man who works with small tools. Ask yourDealer for Williams’ “‘Super- rench”’ Electrical Set No. 1120. J. .H. WILLIAMS & CO., **The Wrench People’”’ 246 Vulcan Street, Buffalo, N.Y. Every “Superrench”’ is Guaranteed for Life Against Breakage ILLIAM 99 ee (Chrome-Molybdenum) MIDGET ELECTRICAL SET POPULAR SCIENCE MONTHLY Hammering Metal Trays (Continued from page 81) not to drive the work out of shape to any great extent. You will soon get the knack of it. Frequently, lay the tray upside down on a flat anvil surface and straighten it out. Be sure to anneal it several times during the opera- tion. The procedure is the same for triangular, EMBOSSING HAMMER Fig. 4. Cross section of a turned wooden mold showing how the tray is held in place and the embos- sing hammer is used. VISE Fig. 5. Tool for mak- ing trays. which have straight sides and how itismanipulated. Fig. 6. Method of ornamenting trays with an embossing tool, which is used like a punch. hexangular, and other trays with straight sides. Any of the trays can be decorated by laying them upside down on the end grain of a block of wood and driving up the metal with a blunt center punch in such a way as to form a pat- tern of raised dots or “‘bosses”’ as shown in Figs. 2 and 6. The embossing tools may be filed from mild steel rods as shown in Fig. 6. Boltheads may be used to make large em- bossing tools. A cold chisel with a blunt edge will form a raised line but care should be used not to break or cut through the surface of the metal. Sometimes the work is placed on a block of lead for this embossing work. In the next article of this series the making of simple bowls will be explained. You can make BIG MONEY WITHOUT CANVASSING. Our FREE PLAy shows you how to build up a permanent, repeat business of your own, ling saws for carpenters, mechanics, contractors, hardware stores, factories and map others, with the Foley AUTOMATIC Saw Filer. The Foley beats the best gh -filing, and there is no other machine like it. $2 to $4 An Hour In Spare Time Others are doing it, why don’t you? Fy. ler made $3 in 40 minutes. Harper made $52 extra in one week. Smith filed 209 saws and everyone is satisfied. You can start in spare time. BE YOUR OWn BOSS—investigate the FOLEY marie SAW FILER MATIC Saw users want their saws filed on the Foley because they cut better and stay sharp longer. EASY TO OPER- ATE. Files all kinds of saws. Send coupon for FREE PLAN and complete infor- mation AT ONCE! FOLEY SAW TOOL CO.. Inc., 1006 Foley Bidg., 11 Main Street N. E., Minneapolis, Minn. Please send me FREE PLAN showing how I can make BIG MONEY in spare time filing saws on the Foley. ee ee Street ... THIS: pe ONLY 1024 Why not live in a modern new home of your own instead of in an old and shabby rented house that is costing yous fortune every year? You can build a new home on the ST LING PLAN and pay for it with your rent-money— as low a .10 per month for a 6-room house. We even advance cash t0 Ze help you build, if you own a well located city lob Build Now and Save Money! We ship you any home you select, ready to Slumber cut to fit, FREIGHT. PAID TO your STATION. Big discounts for cash. rices in the history of our company. Briss in coin today for beautiful Celor Book Sterling Home Plans and select the home that you want us to ship you. International Mill and} Timber Co. ider ‘Agents 44 Styles, colors and pment Boo J pee] fide and exhibit money. y omer fo intend Weship onan. Days’ Free Trial, direct from FACTORY. Get our marvelous offers before buying. Tires , horns, hosts, equip- Tires i? and repairs at usual price. Company Write us © This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8 Mead s2t.ccmtag: \ Chicago free catalog 9410 Wenona Ave., Bay City, B S85TSSzs ¢ d — —T

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Aprit, 1929

Landing Gear for Models (Continued from page 106) assemble your model, the front floats

POPULAR SCIENCE MONTHLY 127 A new

cary last month and shown in ———— ° . a . 102 (see page 108) were arranged to No. | to small sockets on the inside of the A- VO He 1n 1 . 4 and four small hooks were used to ~ ee the silk thread bracing to the A-frame a PLAN = brace at the front and to the center cans ling ant on the A-frame behind, thus holding the ntractors, POINTS TO FIT. SOCKETS SNUGLY wa S nd Many ~ eo OMATIC SN 74, LONG , the best yy OVAL CURVED r machine Vib BAMBOO, AT LOWER ~ ‘6 , exe our FRONT all le SIDE VIEW oF CEMENT aes TOP VIEW REAR SKID ede te “an Fig. 4. Top and side views of the rear skid and filed 209 an explanatory sketch drawn in perspective. You can R OWN floats securely in peo With oe any - are now ready to assemble our land- ? TILER Peg in the Same Way a gamdetud Another Upson Achieve- | ke another look at Figs. 2 and 3 and study . 7: PR cass in which the parts are joined. It ment... Relief Ceilings is easier to fasten the wheels to the crosspiece | gh) 47 give all the dignity first by cementing on the axle. Do this so that | Spee : the wheels are parallel . each other and - anda distinction of mod- hly. Then fasten the two struts to the : smespiere as close to the wheels as you can. | ¢led plaster...at a fraction

ts i = Se PS ie <n he oo —_ Truly walls and ceilings are can mabe Pd PIN the keynote of every home— lo Va ‘ili y

Be sure that they are set at the proper angle. It is well to. use two coats of cement on the strut junctions, as they are subject to consid- erable stress in taking off and landing. Next, taper the outer ends of the vertical struts so that they will fit into the sockets on the frame. Fit the assembled chassis to the frame and carefully attach the silk thread

(0} LATEST TYPE LANDING GEAR

Fig. 5. A new type of front landing gear for advanced model makers to experiment with. bracing, which should be neither too tight nor too loose. Note that the front threads do not cross and that the small wire hooks are fas- tened on the front bamboo cross member of the frame. The rear silk threads, however, cross and are then hooked to the center cans on the frame. To make the regulation type model tail skid, lit two pieces of bamboo 1¢ by ¢; by 6 in. and pe them to an oval section. Make a third piece 1g by & by 714 in. and oval in section. Bend one end of this piece as shown in Fig. 4 to form the skid. With these three parts carefully made, you have only to assemble them as shown. Remem- ber that the upper ends of the tripod pieces should be made to fit into the sockets on the frame of the model so that the rear skid can be disassembled quickly, the same as the front is. Titles for Amateur Movies N MAKING titles with amateur or 16 mm. moving picture film, use 2 ft. of film for THREA Ho ner f -_ Pm. . portunities! These new and aris- BALSA Fd U : cc - »» VENEER SECTION A-A tocratic ‘‘Relief Ceilings of its cost. Ww HAT does your home say to your friends? Does it reflect your pride— your personality? Does it fairly suggest your prosperity? the background for furnish- ings. Ceilings are decorative op- bring within the reach of everyone the beauty of mod- eled plaster—a type of decora- tion hitherto available only to the wealthy—even more to be desired than paneling! We will gladly furnish de- tailed suggestions which any good carpenter can follow. Nothing is handier about the house than a few panels of Upson Board. You will find dozens of uses for it—for screens, table tops, tool racks, hampers, sewing boxes and countless other articles. Certified tests prove that Upson Board and Upson Fibre Tile excel in resist- UPSON

SPRAWLING, CRAWLING CRACKS BANISHED FOREVER! By Upsonizing, unsightly walls and ceilings —too oft nog lected—may be easily renewed and beautified. No longer need any room in the bouse be @ source of constant embarrassment and apology. ance to jars, blows, heat, color, moist- - ture — even ordinary leaks as compared with heavy brittle boards. You'll like Upson Board! Let us tell you more about it—and about Upson Fibre-Tile which builds washable tile- like walls at about 1/1oth the cost of ceramic tile. BOARD We invite you to mail the coupon today

: J The Upson Company, 427 Upson Pt., Lockport, N. Y. " Name every four words if the title exceeds eight - ‘ ‘ ott RWWA n . Enclosed find 10 cents for samples of Upson Board and =: = words. For a title of less than eight words, use Upson Fibre-Tile, literature describing the new Upson i er eR ee 2 ft, of film for every three words. It is not Relicf Ceilings and folders showing how Upson Fibre- neon good practice to use less than 2 ft. for any Tile builds colorful kitchens and baths. I am interestd in eee title—H. N. W. 0 Kitchen or Bath Sa C1 New Ceilings [) Office use

©1929 The Upson Company, Lockport, N. Y.

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128 There’s a treat in store for YOU Hammer users who have yet to try the wonderful Cheney NAILER have a real “kick”? coming to them. Since the days of the first claw hammer there has never been a hammer im- provement that equals the marvelous nail-holding fea- ture of the Cheney NAILER. How many times you have wished for a hammer that would allow you to set and drive a nail one-handed in places hard to reach! The Cheney NAILER is IT. Tool users everywhere proclaim the NAILER the handiest hammer they ever laid hands upon. Ask your dealer today for a Cheney Curved Claw Ham- mer in a 16 oz. or a 20 oz. size. Each one is a NAILER and there is no extra cost. ZENS Ss 806-110 LAFAV ETTE ST. NEW VORK CiTy POPULAR SCIENCE MONTHLY Who Can Match This Shop? (Continued from page 79) torches and both plain and electric soldering coppers; the bottom part has fire bricks and accessories for brazing and welding, as well as various electric heaters and gluepots. The general workbench is shown in Fig. 3. On the bench is a combination motor-driven machine, including a lathe and a circular saw, the portable motor of which can be used to operate either the bench drill or the scroll saw at the right of the lathe. At the left is another portable motor for drilling, and grinding. In Fig. 4 is shown part of another large room. The woodworking bench in the center carries a motorized bench shop consisting of circular saws, planer, sander, and drill, as well as a heavy woodworking lathe with a 4 ft. long bed. Fig. 6. Cabinet containing wood and metal working tools, including micrometers, taps and dies, assorted C-clamps, and wrench sets. At the rear is a large motor-driven jig saw and a high-speed lathe. The rear of the woodworking bench is shown in Fig. 5. In this part of the shop is a small band saw, a rack for lumber, and also complete equipment for painting. Mr. Stuhler has found an electric shaper and a jointer to be almost indispensable for making moldings and doing cabinetwork, but these machines are not illus- trated; neither is a portable electric sander. The tool cabinet shown in Fig. 6 is 8 ft. high and 10 ft. long. It contains tools for both wood and metal work, including carving tools, micrometers, gages, taps, dies, and miscella- neous tools, all of nationally advertised makes. To mention the manufacturers of the tools and machines used by Mr. Stuhler would be to call the roll of the tool and machine advertisers of this magazine, as he made up his mind in the beginning to purchase nothing but equipment of high quality and well-proved durability. Small Crucible Made from a Battery Carbon HEN the amateur mechanic wishes to make small castings of brass, aluminum, and various alloys, he can make a crucible from an old dry cell battery carbon. Take out the carbon, secure. it firmly, and drill as large a hole as practical —ordinarily 44 or 54 in. — through its center to within about 14 in. of the bottom. Scraps of the metal to be melted can be placed in this hole and the car- bon heated in any available flame. A small coal forge has been found convenient, for the coal may be packed closely around the carbon, holding it upright.—OLin Atwoop. A PUNCHING bag to amuse the children can be made by inclosing an old inner tube in a sack. The tube should be doubled in such a way that the valve is folded in toward the center of the punching bag. An old pair of gloves should be used to protect the children’s hands from abrasions.—JouNn Boscovicu. The Radio Knife Electrician’s Favorite Hs a fine practical tool for the professional electrician or mechanic, and for every man or boy who tinkers with a radio or other electrical equipment. The screw-driver locks in place when open. It can’t shut on your fingers. This blade has an edge for scraping the insulation off wires, Then there is a good sturdy sheep- foot blade for all ’round use. It’s razor-sharp —hand-honed at the factory. Made ofjhigh-carbon steel that holds a biting edge. Hand- some Cocobola handle — nickel- silver bolsters and shield. This knife belongs in every tool kit. At your dealer’s. If he hasn’t it in stock send us his name and $2.00 for R 4548. It will be mailed promptly. REMINGTON ARMS COMPANY, Inc, Originators of Kleanbore Ammunition 25 Broadway 4 New York City ~*~ RADIO -— REMINGTON er ectaicrans BE Popular Play a Conn band or orchestra instrument and you're wel- come everywhere. Win pleas- ure and profit playing part or whole time. With a Conn you play tunes the very first day. Easy playing features and new instruction methods make it fun from the start. FREE TRIAL, Easy Pay- ments on any Conn. Write for literature, details. Name instrument. No obligation. C. G. CONN, Ltd. 2432 Conn Bidg. Elkhart, Ind. CONN INSTRUMENTS UM) ant an uncrumane: ApRIL, ] safe, inve Wit

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>} RIL, 1999. pau, 1929 POPULAR SCIENCE MONTHLY 129 y/ The Motorized Workshop Of Your Heart’s Desire Make the Things You Have Always Wanted to Make ene rs Quickly

4 Patented Jan. 1, 1929 ; ‘1 Hi ~ 4 i « "g i ‘ite 4 : anor F : in or iO or ‘ Place q ‘ your | f e for a i ‘ites, § : LE : . It’s z ‘ : the F : Steel i i and- ; : ckel- t ook Easy to Make asn t ° and So Many Things iled Pleasure and profit are derived from the possession of this This new, patented Delta Handi-Shop is just pare the finest — ee home workshop that can be built. In performance, appearance, anc. safe, permanent and profitable permanence, and cost, the Delta is in a class by itself. Now you | G investment. can actually make the things you’ve always wanted to make ¥ eeeee with ease and speed, because this complete, sturdy, efficient, man-sized, motorized workshop takes the drudgery out of BLUE PRINTS wood eraftsmanship. practical motor for the "werksbor INCLUDED a , Bormits you to carry on two or three You can save money on the odd repair jobs which are always needed around the inp portant operations at on i house. And this great, practical shop will enable you to turn your spare time into set-up. y- dismant ing the profits. You can make enough to pay for the Delta Handi-Shop in a short time. All DE LTA UN ITs F ave n. 4548 The Delta Handi-Shop includes all necessary equipment for circular sawing, x eae 9 ».00 wood-turning, jig sawing, sanding, drilling, grinding and buffing. ' : centers The Delta Has Many Basic Advantages F Sa Heavy Trip rs oundation - Note these big features: The powerful, constant-speed two-shaft Motor and the peo gy: athe Be Bed heavy U-shaped Lathe Bed, the improved Circular Saw, Jig Saw and Sanding is GUARANTE! whether you ova weemehep or hi tu t not. omplete rections, Hundreds of Owners Ta aaa ae illustrations, diagrams. Con- Prai sé ” TRIAL OFFER and your choice of — important informa. raise the Delta three convenient methods of payment. _ . Sp oad If you Easy MAIL COUPON TODAY. pp = Re ay nen Mr..H. *Ressel wrote that he of mailing. See coupen built a fence, repaired furniture, below. built a double arbor, made a [ pe PEC ALTY CO. bookcase, sewing cabinet, can- DELTA : SPECI ~ tt dlesticks—all with the Delta and . ae ee ee oe from our blue prints. He writes: (Check material desired) “I've enjoyed this workshop oO ase ont — Cte, Se ae like I have never enjoyed any- Shon Kine Tall details ‘Of 10 Day Trial of Oder and Easy thing in my life. It is so practi- 1 Payment Plans. eal, so convenient, that I can’t { Oo Please send me copy of ‘How to Make = help wondering and marvelling DELTA SPECI ALTY co . l a Workshop.”’ I enclose 10c to cover cost of mailing, ee. P 1661-67 Holton St. Milwaukee, Wis. | Name Dept. B-49 | CS ee ee

@ This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval cf the INSTITUTE OF STANDARDS. See page 8.

Page 124

Not Hurt.... Just Terribly Disappointed Herman (“Rusty”) Tee, former world’s champ- ion pipe wrench baffler, protests against the roughtreatment he received from a Trimo: *No, I’m not hurt,” he admitted, “not even scratched — just terribly disap- inted. If the d used an ordi- n ipe wrench, gtk d still be champion. I con- sider that it was unsportsmanlike to use a Trimo.” There’s plenty of weeping and wail- among stubborn ipes when Im- proved and Mightier Trimo goes to work. When nuts, bolts and i refuse to turn, give the to Trimo. Trimont M jo — c. Roxbury (Boston), Mass. At Hardware Stores Ti Everywher e © POPULAR SCIENCE MONTHLY Heavy-Duty Workbench (Continued from page 94) drawer as required by the size of the opening. 22. Cut out a slot in the apron so that the drawer may be opened without using handles. 23. Bore 34-in. holes in the apron and per- haps one or two in the rear leg where pegs may be placed to support wide boards on edge for planing. 24. Fit an iron bench stop, placing it about 3 in. from the front edge of the bench top and not nearer than 6 in. from the left end. Materials for Bench What Lumber to Order No. Part Pes.T. W. L. Top (pine or maple)...1 2 8 14 ft. Bottom for trough and lower crossrails.... 1 1 8 16 ft. en 1 1 12° 14 ft. Shelves, upper cross rails, and stretcher. 1 1 12 18 ft. RE EEE ee ze a 8 ft. a ER See 12 4 6 ft. ee 1 2 10 6 ft. Vise jaw (maple)..... 3 f & 2 ft. 6 in. Follower (maple)..... gti 4 2 ft. 6 in. Back for vise (maple). 1 1 8 2 ft. 8 in. Strip for tool trough.. 1 1 1% 12 ft. Drawer bottom (3-ply) 1 14 24 24 Dowels (birch)....... 1 4 dia. 18 in. All dimensions are in inches (and all material is hard pine, dressed four sides) except as noted. This lumber, because of the waste in planing, will be less in thickness and width than stated here; 1-in. boards D4S are about 13/16 in. thick, for example. Hardware 1 lb. eightpenny box nails \% lb. sixpenny box nails. 1 screw for vise. 1 bench stop. 1 small machinist’s vise (if desired). 1 dozen 24-in. No. 12 flat-head bright screws. Sizes of Finished Pieces | No. Part Pcs. T. x. ie - REY 2 1% 7% Tt. . erry ree 1 13/16 7% 7 ft. MRR i ars oceans 1 13/16 1% 7 ft. Aprons........... 2 13/16 11% 7 ft. Upper cross rails (end rails)...... 2 13/16 10% 21% Upper cross rail... 1 13/16 5 213% Lower cross rails (cut from 1 by 8 . in. board)...... 3 13/16 35, 21% Drawer rails ..... 2 13/16 9 21% ee 2 13/16 8 21% Stretcher (cut after bench is nailed WN oo creaiminaeas 1 13/16 9% 6ft. eeeTe ee 2 1% 3% 2 ft. 6in. | Legs for vise end ee 2 1% 9% 2 ft. 6 in. Backing for vise (maple)........ 1 13/16 71% 2 ft. Sin. Vise jaw (maple; cut top end after fit- ting vise screw).. 1 13% 7% 2 ft. 5in. Follower for vise (maple)........ 1 13/146 3 2ft. Drawer front Gpine) 1 13/16 6 2 ft.4in. Drawer sides...... 2 13/16 6 20 Drawer back...... 1 13/16 5% 26% Slats to support drawer........ 4 13/16 1% 20 in. Drawer bottom (cut as needed from 3-ply). All dimensions are in inches except as noted, li r MODEL AIRPLANES That Fly—Only $1.50 Comun d Postpaid BOYS - Here’s the greatest value you've * ever seen. A Gpauiee aluminum model airplane that really flies, at @ smalj PrThe “Mocar” monopl Set N ane— Set ° copy of Lindbergh's famous Spirit Of St Lang Wing spread 18 inches, fuselage 12 inches, erful motor, special propeller, rubber-tired disy . Weight complete only about 2% os, This is a practical, simple, real mode! that gives you a whole lot of fun at a very mod. erate cost. The all-metal construction make a sturdy plane that will stand a lot of The outfit is mounted on cardboard with parts plainly marked and full instruction for assembly. Pliers only tool necessary. Cop. struction Set No. 1 complete with rivets, bolts, wheels, wing and fuselage covering material, only $1.50 postpaid (3 for $4.00). Model L made up ready to fly $2.25 (3 for $6) postpaid. Great fun,learn how to make and fly airplanes. ORDER NOW OR SEE YOUR DEALER \ Ry) c THE MOUNT CARMEL MFG. CO, New Haven, Conn, Dept. S. with a Buescher First-class Saxophonists make big money and the work is easy and pleasant. You might become a great record-maker like Clyde » whose picture is shown with his Buescher. $100to$500a week is not unusual for good musicians to earn. Even if don’t care to be- come a profess’ , you can have a lot of fun and earn extra money with a Buescher Saxophone, 6 Days’ Trial onany Buescher Saxo- b, . Trombone or other instrument, Mention instrument in which you are interested for free literature. (494) Buescher Band Instrument Co, 2744 Buescher Block, Elkhart,ind, YOU’LL BE DELIGHTED WITH YOUR H&A BAND SAWg Here's the Saw that’s doing excep- tional work in thousands of facto- ries, shops and manual training schools — a high grade precision tool; portable, motor driven, reasonably priced. Skilled or unskilled, it will help you do better, faster work— at a sav- ing. Writefor attractive price offer. HESTON & ANDERSON 804 Market St. FAIRFIELD, IOWA Boys: join a Zip-Zip Shooters’ club everywhere boys are forming thes clubs, fine sport using this shooter which is scientifically and practically made. Zip-Zip Shooter is the best buy we know of for 35c or 3 for $1.00. We will ship to you if your dealer can't supply you. AUTOMATIC RUBBER CO.,Columbia, S. C. corner of the to a SC stantl tingu! E* fi throu paint This sauce

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29 POPULAR SCIENCE: MONTHLY 131 APRIL, 19° — eS SS S Hints for Home Owners % sn Lan ‘Strike’ (Continued from page 102)

corner of the bathroom door and down the edge of the door jamb, and fastened at the lower end toa screw eye about a foot from the floor. This arrangement is not unsightly and may be in- stantly located by all. A pull lights or ex- tinguishes the lamp.—CHar.es F. H. MIxts.

ARTHENWARE saucers used to support flower pots often permit moisture to soak through to the bottom, with the result that painted or varnished surfaces are damaged. This can be prevented by waterproofing the saucer with paraffin. After the saucer has been heated in an oven or over a flame until suffi- ciently warm to melt the paraffin, it is rubbed with a piece of wax (Fig. 3). The porous saucer absorbs the melted wax but does not change its color.—W. E. B.

FTEN those who live in apartments and other restricted hoger pe a seriously = nvenienced by the lack of adequate space for ? ilnsing clothing in such a way as to permit easy What You See : A sandpapered alley of ee ee eee a. He dee Zi hardwood with ten duck pins lined up shown in Fig. 4 will extend the capacity of an g = a overcrowded closet by as many suit hangers as | at the end. A well aimed ball, skirting the length of yee! age arm = ne. _ the edge of the alley, curving in to strike it will not interfere with articles hung else- ° where in the closet. ‘The arm may be made the pins between numbers one and two. longer than indicated, or the hooks may . aragt closer oe if only light articles are 6 What You Don’t See: The painstak- | to ung on them. m Make the arm 7% by 214 by at least 12 in., ing work of the saw filer who used ne en Le tee | tj a Nicholson File to sharpen the saws ‘hooks on the underside at A, a screw eye in the HH7. e e es Band a 1}<-in. No. 10 round-head A which, in turn, cut the lumber for serew in the end at (, boring a small hole to tj the bowling alley. reeeive the latter without splitting the wood. Place a 2-in. hinge at D and fasten the arm to the door as shown, so the end of the arm will Throughout the realms of sports, clear the top of the a oe — tty industry and the home . there are Place a 14-in. hook at the top of the door anc g e fasten a light chain or cord to the hook and to ti thousands of jobs that only a file Sones 5, making it just long qrongh to mp. | @ can do. Hardware dealers can port the arm horizontally as indicated. A key Z . e ring in the hook may be easily slipped over the supply you with shapes and SIZES screw C when the arm is lifted up for closing for every demand. Booklet “Files the door—Cuar.es A. Kina. Z g All Over the World” will be sent to you free upon request. VEL S , é ARLE? 1g, ee MLE RLS

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FOLDED - UP POSITION Fig. 4. This folding arm on the back of a closet door holds several extra clothes hangers.

© This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8.

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iB POPULAR SCIENCE MONTHLY cbue- ots So Bn bs Me Dg

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a Paper Bird Flaps Wi When Tail Is Pulled

AB How to fold the basic form to which various bird and butterfly shapes can be attached, B FOLDING a single sheet of paper as shown, you can make a bird which wil flap its wings when its tail is pulled. Different wings, bodies, heads, and tails can be pasted on the elementary form. Butterflies can he made similarly, and it is also possible to con- struct animals with ears that flap. The steps in folding the bird are as follows: 1. Prepare a square of paper of any convenient size. If you wish to make a canary bird, paste yellow lawn on the paper. 2. Crease the diag- onals AD and BC. 3. Crease EF and GH. 4 Crease CD to center of square. 5. Do like wise with CD in the opposite direction. 6. You now have a triangular crease from C to D at one edge of the square as indicated at F. 7. Crease the other sides of the square similarly to form a star figure; then spread the square out’ flat. 8. Tuck in triangle ACK and BDL (se Fig. 7), at the same time folding the paper in half along KL. 9. Similarly, tuck in triangle CDJ and ABI (see Fig. 7), folding the paper at the same time along IJ, so as to obtaina figure like a partly opened umbrella. The points F, E, G, and H are inside toward the center. 10. Fold AB, CD, JK, and IL together seeiathdeenen

flat on the table in front of you. 11. Raise corner C' to bring out the neck. Crease down corner C to form the head and beak. Raise corner B to form the tail. 12. Raise AD to form the wings. Paste the letter in the birds beak. To operate the bird, hold it where marked with a cross in Fig. 12. Curve the wings slightly and pull the tail. — Jeanne I. Orsint. Winding Cord in a Ball Wen winding clothesline or other heavy cord into a ball, all kinking can be avoided if the ball is changed at intervals from the right to the left hand and vice versa. Wind with one hand until the cord begins to twist; then transfer the ball to the other hand with- out turning it around or changing the direction of winding. When the cord has become ut kinked and starts to twist in the other direc tion, change hands again.—Rocer Soar.

ApRIL,

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ngs wist; wi ction » un- lirec- April, 1929 Einstein’s Topsy- Turvy World (Continued from page 19) ‘ag the speed of light, which Einstein eae cenaiy be reached by any mate- thing—loses as much as three feet of its | only to regain it when it stops. “Tatil recently such ideas, involving almost imaginable speeds, might have been of only shilosophical interest—but now we have dis- es at least one speed king of the physical world in the apparently material particles that radium shoots off at nearly the speed of light. In view of Einstein's discoveries, only his theory can detect their real nature. — To understand Einstein’s purpose it is worth while to go back a few years, and to see just how his work clears up difficulties that have bothered physicists for centuries. In New- ton’s time, as Einstein. himself points out, “space,” such as the void that separates the earth from the sun, was considered a dead, empty sort of thing. Obviously it had nothing to do with arrows and bullets; it was just a sort of a stage upon which the sun and the earth, peopled with human beings, performed as actors. app says A VERY satisfactory idea—until, in the eighteenth century, Huygens, Young, and Fresnel—Dutch, British, and French phys- icists—came along with the notion that light was made of waves. The daylight that reached us from the sun was a series of ripples in some- thing or other—but in what? The idea worked too well in- the laboratory to discard, so phys- icists invented an imaginary “ether” and plugged supposedly-empty space full of it. It was‘am ingenious if not a wholly convinc- ing explanation, and for generations no one could do any better. Then Michael Faraday proposed the bold theory that the ripples of light, once started on their way, sever relations completely with their source and splash alonz on their own initiative. That seems a natural assumption now, but even the boosters of the “ether” idea had hesitated to give the mythical gas the responsibility of carrying just “waves” with no apparent source. ess WEL. with his inspired formule, discovered that the waves of light were really electric—a revolutionary idea. On his heels came Hertz, in Germany, to show that what we know now as radio waves are just as electric as light, and that the only difference is one of the length of the waves. Gradually the conception dawned upon the scientific world that light, radio, and X-rays, to say nothing of the recently-discussed ultra-violet and infra-red rays, are all pretty much the same thing—little bundles of electric force, vibrating at different rates as they speed through space. But—and here was the catch —the only way, still, that people could explain how those little bundles got from one place to another was to say that they rippled through “the ether.”’ Enter Einstein. “Away with this imagina ether,” he said, in effect. “This space, whic you have been squirting full of an impossible gas, is not as dead as you have imagined. Live, vibrating space plays a part in every electric or mechanical action.” _ Einstein brought space to life, by enriching it with the “fourth dimension” of time—in his “Special Theory of Relativity,” published in 1905. By doing so he achieved two outstand- ing feats. First, he showed that electricity and magnetism, which heretofore were thought of as distinct forces, were the same thing! Second, he discovered that a material object can lose weight, which becomes trans- formed into electricity. In other words he re- vealed that mass can turn into energy, contra- dicting the notion that mass was indestructible and that the amount of energy in any system could not change. (Continued on page 134) POPULAR SCIENCE MONTHLY Finished in Minutes—Ready for Service in 4 Hours YES KYANIZE Lustaquik Finish will dry in four hours. When your _* handiwork is finished and ready for painting, the matter of choos- ing the right finish and color is just as important as the wood used and the labor you put on the job. KYANIZE is speedy, safe and free from offensive odor. Washable and sanitary, of course. yanize LUSTAQUIK FINISH is used on furniture, woodwork, walls or wherever a quick drying, solid covering and long wearing finish is desired. Easy to apply, self leveling to an even, ridgeless surface. Requires no special thinner and can be applied on large surfaces without showing laps or brush marks. KYANIZE Decal Transfers—lovely little miniature designs in harmonious colors, are easily applied and look just like hand painting. Easy to use—just dip in water and apply. Users call them “Minute Decorations.” Send for our new booklet, “The Charm of Painted Things,” or if your dealer cannot supply you with Kyanize send $1.00 for a special trial paint can with brush and booklet included. Special $1.00 Offer If your dealer cannot supply you, send us his name and $1.00. We will forward, prepaid a full pint can of Kyanize Lustaquik Finish (solid covering), a good brush to apply it, and new Book, “The Charm of Painted Things’—all for $1.00 State color desired. LUSTA- QUIK TINTS: Royal Ivory, Foam Green, Cloud Gray, Blossom Yellow, Ripe Orange, Chinese Green, Tulip Red, Beaver Brown, Platinum Gray, Desert Brown, Blush Pink, Tea Rose, Orchid, French Blue, Fern Green, Valley Blue, Black, White, Clear. BOSTON VARNISH COMPANY 262 Everett Station, Boston, Mass., U.S. A.

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© Why Craftsmen Choose Bridgeport RED CROWN (1) You can hammer the head of a Bridgeport Red Crown all you want. Its hezagonal head, which is a rt of the blade, takes the blows on its broad steel surface without injury. (2) You can’t twist the handle of a Bridgeport Red Crown. The heavy steel rivet prevents twisting and loosening. (3) You can use the Ls Red Crown as a pry bar. The blade is one-ptece from the point to the hexagonal head— made of the finest steel, heat treated and untformly temper- ed throug (4) You can use the Bridgeport Red Crown as a chisel. The point won't “mushroom.” It won't break. It’s DUAL tem- | a by the FH ye Proc- e red crown atop the A bright a identifies Bridgeport : Lewes is the life of a screw driver! Has to pry like a crow-bar; gets unded on the head like a chisel; and withal is expected to remain a good screw driver. No other tool has to suffer such abuse! And for just such a life the Bridgeport Red Crown is especially built. A one-piece blade of the finest steel extends clear through to the top of-the handle. A blade that is specially heat-treated, uni- formly tempered, painstakingly tested. Yet this blade is only one of four extraordi- nary features—features that have given the Bridgeport: Red Crown a strength and toughness that make it last like an old friend, when other tools are long forgotten. Make a mental note of these features—de- scribed above. Then ask your dealer to show ou the Bridgeport Red Crown—identified the bright red crown atop the handle. Look for these red crowns on his counter— 4", 5” and 6"—s50c each. If your dealer can- not supply you—order direct. THE BRIDGEPORT HARDWARE MEG. CORP. Bridgeport, Connecticut “America’s Largest Makers of Screw Drivers” Bridgeport TRAOE TOOLS and HARDWARE SPECIALTIES POPULAR SCIENCE MONTHLY Einstein’s Topsy-Turvy World (Continued from page 133) Application of this second idea came only last summer, when Dr. Robert A. Millikan, California Institute of Technology physicist, discovered that strange “cosmic rays” from the stars were formed of the energy left over when atoms merged violently together to form new elements, losing a part of their weight. Einstein’s “Special Theory,” however, left unexplained the mysterious force of gravity. Even Newton, who deduced the famous laws telling how strongly gravity acts, made no attempt to account for the way the earth apparently pulls things to it. In 1915 Einstein announced a new “General Theory of Rela- tivity” that offered an explanation of gravity. This mysterious force, he said, is not a whit different from the force that holds up a stone swung in circles on a string, or that tips over a car going too fast around a curve—hitherto known as “centrifugal force.” There is noth- ing mysterious about it—it is just a mechanical eect that anyone can conceivably duplicate, irrespective of the earth. [® HE pointed out, you were to stand inside an elevator somewhere out in space, away from the earth, and have the elevator hoisted straight upward at a constantly increasing speed—going twenty miles an hour faster each second—your feet would press against the elevator’s floor just as firmly as they now do against the ground when you walk. It needed some queer geometry to extend this idea to the forces that move the earth, moon, sun, and stars—but Einstein managed it. It led to remarkable results. Instead of acting instantaneously, as Newton had supposed, evidently gravity moves through space with the speed of light. More important, Newton's laws of gravity needed a slight correction when they were applied on a large scale. Einstein made such a correction, applied it to predict the shifting of stars, and his prophecy was duly vindicated. At the same time he made another prediction that was not verified until 1923. He said that distant stars, if carefully examined through a spectroscope, should show a peculiar reddishness. At Mt. Wilson Observatory, California, Dr. Charles E. St. John observed this effect in certain dense stars and found that it agreed exactly with Einstein’s cal- culations. QNE goal remained. Einstein’s special the- ory dealt with electricity; his general theory explained gravity, but a ong a separate line. It remained to reconcile the two under a general law. Now he has linked them in relativity’ s third triumph—the “Field Theory.” Dr. Edwin Schroedinger, of the University of Berlin— author of our most recent conception of the atom, a rather severe critic of the “general” Einstein theory, and the advocate of another theory that differed from it in important points—admits that Einstein’s new theory is the best explanation yet advanced of the con- nection between electricity and gravity. Many experts, however, are not yet con- vinced that Einstein is right. Some of them condemn his ideas completely; others are exem- plified by Prof. Albert Michelson, American physicist famous for his measurments of light, who recently declared in substance: ‘‘I am now ready to accept the consequences of the Ein- stein theory, even though I believe that he has made correct results grow from incorrect as- sumptions.” Meanwhile, according to Prof. Freundlich of the Einstein Institute, it will take between two and five years for the few men who can understand the latest advance to study it, find out what it is all about and test it. It may be ten years, experts agree, before we may expect practical benefits from the latest feat of human imagination. GEN BALANCE EASY TERMS plete CHINE GUARANTEE. act now! Yours for 10 —If You MONEY ORONA 4 LOWEST PRICE ever offered J chancetoown that genuine Model 3 Corona you’ve wanted— on the easiest terms ever offered—at LOWEST PRICE every offered! Com spacer, etc., NEW MA. over as the finest, strongest, sturdiest, portable built. Only a limited number of these Splendid machines available. To get one, you mug Send No Money Experience the joy this personal writing portable typewriter can give you! Use it 10days free! See how easy it is torun and the splendidly let. ters it turns out. Ideal for the eee d traveling. Small, compact, li Don’t send out letters, oy ay handwriting when you can have such a low price or on such easy terms, Carrying Case Included Leatheroid this offer. Sen delay or red tape we will send Bt yp py al This aan may never be UINE in every detail; back Recognized the worl Days FREE~ home, at in poor this Corona at Act Now ng case, oiler, instructions fs on no money — set the ——. ya Lk yf he rojas a 8. ‘ou ie ee} » 8c us 0 z wes ot 20 pal. Re SAVED By Using This Coupon & 469 E. Ohio St., Chicago, Dep me the Corona, a wih Himeten ts wrens If Y Bes ere Pigeng 73 you $3 ae Pe eee Gee... ...ccccsdandadicocissncsccceendl CP on ee ee EE eee ee day with an easy-playing Conn instru- ment and the fascinating new in- struction methods. No long drudging over scales. Conn gives you the exclusive features found in no others. Choice of famous artists. FREE TRIAL, Easy Pay- ments. Write now for liter- ature; mention instrument. - CONN, Ltd., c.G 432 Conn Bldg. Elkhart, Ind. with f for th he car lation: abilit Nobe T= a house murd cover exper Th cellar the o a sin

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fi

_ wes... ae , 23

APan, Igy past, 1929 POPULAR SCIENCE MONTHLY 135

go ae, People Worth Knowing (Continued from page 26) - auished Norwegian _explorer, scientist, and statesman, is planning to revisit the Arctic in April of next year. Thirty-six years ago, he started out on the expedition which made him a widely n figure, in the Fram, a stout wooden _ vessel of his own design. On his next » into the white wilderness Dr. Nansen will the Graf Zeppelin, the giant dirigible de- = and built by Dr. Hugo Eckener, who flew her across the Atlantic last autumn and who may pilot her during the Nansen expe- So Nansen announced the other day that he intends to fly from Leningrad, Russia, to Nome, Alaska, a distance of 4,000 miles. The direct purpose of the Arctic survey will be to determine the exact extent and depth of the Polar Sea, but its ultimate aim is the establish- ment of a complete system of weather stations in the Arctic regions. : 7 The expedition will be the crowning acliieve- ment of a career of unusual romance and ad- yenture. Dr. Nansen’s hope is to complete the work he started in 1893, when, on foot, with only one companion, he advanced 184 miles nearer to the North Pole than any one had then reached. But his career as an explorer began earlier than that. When only twenty- one, he visited the east coast of Greenland to secure rare zodlogical specimens. Six years later, he made a journey across the inland ice ef Greenland. His polar trip in the Fram made Nansen world-famous. On his return to Norway, he was showered with honors. He became one of the leaders in the movement for the separation of Norway from Sweden. In 1906 he was ap- pointed Norwegian minister at London. Two years later, he resigned to accept the position of professor of oceanography in the University of Oslo, his Alma Mater, a place he has held, with few interruptions, ever since. Immediately after the war, Dr. Nansen was made chairman of the Norwegian Association for the League of Nations. In this capacity, he carried on relief work for the starved popu- lations of Russia and Asia Minor with such ability and success that he was awarded the Nobel Peace Prize in 1922. ‘An Honest Safe-Cracker T= police of New York City recently had a perplexing problem. In the cellar of a house that had belonged to Arnold Rothstein, murdered gambler, a huge vault had been dis- covered. The police wished to open it. Several experts failed. Then a smiling young chap walked into the cellar, tinkered a bit with the combination of the outer vault door and, without the aid of a single tool, had it open in three minutes. The inner door was fastened with an intricate key lock. A hole was drilled. In twelve min- utes this door, too, was open. Robert S. Murray, the man who cracks safes for an honest living,-has reduced this strange profession to a science and an art. In the past fifteen years, he calculates, he has opened 15,000 safes. In the last eighteen months, the number has averaged between three and four a day. Murray has opened safe doors on which operations had been started by burglars who | forgotten large charges of dynamite in theirhurried departure. He has assisted in locat- ing love letters, blueprints of inventions, and family heirlooms. His services are solicited from all parts of the country. His longest job was done in a little Indiana town, where he labored thirty-six hours at a stretch with but two hours off. In contrast to this siege with one safe, he once opened 104 safes for the United States Ship- (Continued on page 136)

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© This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8.

Page 130

If you’ve never tried a MAYDOLE you've missed something -- _A “hang”’ been equaled Heads press-forged from the finest tool steel Clear, straight grained, air dried hickory handles care- fully shaped to fit the hand and put into the heads ‘“‘for keeps”’ that has never Strong, sturdy, well balanced—built to withstand years of hard use. Driving or pulling, there’s more in a Maydole than in any ordinary hammer. Your dealer carries a complete stock, ask him to show you the style and weight that fits your grip and swing. Write us for a free copy of Pocket Hand- book 23 B containing handy tables and useful information. WMaydole Hammers The David Maydole Hammer Co..Norwich. NY 2652 POPULAR SCIENCE MONTHLY Glimpses of People Worth Knowing (Continued from page 135) ping Board in three days at Norfolk, Va. “How do I do it?” says Murray. “I can’t tell you. It is a knack that comes only with experience. My technique, if I may sa call it, is my own.” Murray, who was born in Danville, Pa., started as a mechanic in a small Ohio town. When he was twenty, his father, brother, and himself bought out a safe agency in New York. He was instructed in the rudiments of honest safe-cracking by an expert and has been crack- ing safes ever since. An Engineer-Farmer HANDSOME, fashionably-dressed man boarded a steamer for Russia the other day. He sailed to aid the Soviet government in developing 10,000,000 acres of grain land. The vessel’s passenger list named him as “Thomas D. Campbell, farmer, Harden, Montana.” That one line concealed a remark- able story of successful application of scientific and mechanical ingenuity to the farm problem. Campbell is the world’s largest wheat grower. He farms approximately 100,000 acres, which yield an average of almost 3,000,- 000 bushels a year. On his giant farm, one solitary horse may be found—Campbell’s sad- dle horse. Five thousand horses are dispensed with by his machines. These include 109 tractors, 500 plow bottoms which can cover about 1,000 acres a day, 100 planting machines that can drill and seed 3,000 acres a day, eighty binders which can cut from 1, 500 to 2,000 acres a day, six twenty-four-foot “ com- bines” capable of harvesting and threshing 800 acres a day, and eleven large threshing machines which can turn 20,000 bushels a day. In addition, there is a big fleet of cars and trucks, among them 100 six-ton grain wagons, drawn by tractors, that carry the threshed grain from field to elevators; thirty- five passenger autos and trucks, and many fireproof steel storage bins, all movable and on skids and with a capacity of 100,000 bushels of grain. Each day on Campbell's farm there is plowed the equivalent of a furrow ten feet wide extending from New York to Chicago. His tractors daily consume more gasoline than all of the Fifth Avenue buses in New York City put together. One machine he has per- fected, operated by two men, seeds an area sixty feet wide and three miles long every hour, or a total of 200 acres a day. Another machine plows, disks, seeds, packs, and har- rows in one operation thirty acres a day; it, too, is operated by two men. Still another har- vests, threshes, and loads grain in trucks at the rate of fifty acres a day at the cost of a dollar an acre. No wonder that Campbell says, “‘I am really not a farmer; I am a mechanical engineer. We manufacture wheat almost instead of raising it. I have no farm hands, but skilled labor, drawing salaries as high as the proverbial plumber. Most of my men are engineers themselves.” Campbell started this tremendous enter- prise as a patriotic service to his country when there was a grain shortage during the war. He began by offering the Government his services as a dollar-a-year man. This was not accepted. Instead Secretary Lane, of the Department of the Interior, assigned to him 200,000 acres of Indian land in Montana and Wyoming, so arid that horses can scarcely survive on it. In a little more than ten years, Campbell, from this dry waste, has wrested more than 100,000 acres yielding twenty-nine bushels to the acre at such low cost that the much-mooted ‘‘farm problem” doesn’t worry him. Please send me the Town and State. jin awes Am interested in house. So aiaicmaandie garage... summer cottage..... for it now. Bennett Homes, 1049 North Tonawanda, N. Y only in Ohio, New Y vania, and New England. Appt, | Planning to . build? If so you will want this m One y-Saving Bennett book of 109 beautiful homes, Send Main St, 90-page Bennett Book, Free ork, New Jersey Elsewhere $1'00 Pennsyl- eyes. ec gente. pellers, etc., and fine tools page photo mation an ecome greatl — receiving i will be sen MODEL SHIP$§ Would you like to build a regi fine ship model? We can supply construction sets and parts such a8 semi- falebed bulls, Boe anchors, si r boa ; or ee maker. i trai jet con: ‘ews for or. building t postpa! ressigt of 15cts. (coin oo Ey lapel ensign for —_ model t enthusias rto in two styles. spoke has a small rii —— style ‘illustra hub and also be worn Packed in a handsom $1.50 pos style = ordering. Model Ship Supply Co. Mineola, i. Y. A real riate At Last watch shan ar coat makers This miniature e charm, one qttaches. The nut for fastening. on aes Fs po e case. itpaid. Be sure to mention Se Se ~/\ lathe, == und 18-inch rest le, scroll, rape dl bandsaws, and sories for aero buh Attaches to light wocket = °Fre shop. ONLY #$ ee Crafts WAC a" va : y Kiely ing. grinding and Instructive, Fascinating, O TOOL W oo you private mm» Comes oa Y Blecprint Servien send ¢ Coupon for Interesting Literature. You will WORK s, Inc, 5216 W. Kinzie St.. Chicago. Dept. 4s send me ail information FREE. tory type instrument. tists, Physicians, D quick adjustment by sides of tube. stage with clips. mirrors, precision microscope money . buy fled after 30-day check, money order Catalog free. Dept. C Ph .. same as used by Selens tists and professional I Ph "x Special slides from breakage. objective gives different powers and large, clear field of great depth. Square J Adjustable iris dia- phragm, with plane and convex Adjustable stand. A with handsome case. direct—money refunded if not ‘absolutely satis- trial. Send Govaraiue Engineering Co., » 2006 Chestnut St., Hadelphia, Pa. wicasseors jj OWN this fine, laborae Has knurled nuts both device protects Triple divisible complete Save or cash.

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IPs = a ~ & Hirde

vor

Aprit, 1929

A Machine That Makes Heroes (Continued' from page 23) iving set equipped with ear- aie oct Resdies wave lengths from 500 to 1,100 meters, and is tuned like any radio set. A light, which flashes in — with the dots and dashes of code, ae hes a pilot to read signals while standing of the other side of the room. ; ; At the top of the main case or binnacle is a “dummy” compass, a flat metal scale marked off with 360 degrees, with zero pointing toward the ship’s bow. Above the compass is a wire stretched across wishbone-shaped prongs at- tached directly to the shaft and turning with the loop aerial. When a hand wheel on the shaft is revolved, it turns the aerial on the roof and the wire over the compass. The wire is at right angles to the plane of the loop, so when the open side of the aerial faces the source of a radio signal, the wire points directly toward it. The reason for this is that the point of lowest signal strength is the one used to determine direction. It is difficult to pick a point of loudest volume, but relatively easy to deter- mine the position of least volume, just before the complete “fadeout.”” When this is found, the wire, pointing at right angles, aims direct- ly at the calling ship. , All radio compass bearings are taken with reference to the ship’s head. If a signal comes from directly in front, the wire points to zero on the “dummy” scale. If it comes from one side or the other, the wire indicates the number of degrees to left or right and the ship’s course is altered in that direction. In some ships, in- cluding the America, the “dummy” compass isreplaced with a magnetic or a gyro compass. In this case, the wire indicates the position of the calling vessel in respect to north as well as in respect to the ship’s course. eight-t phones. Bers playing a stellar réle in sea res- cues, the radio compass enables a captain to determine his own position in a fog. He need only listen to a shore beacon station, mark the line of its incoming signal on his chart from the beacon’s charted position, then listen to a sec- ond beacon station and do the same thing. Where the two lines cross at sea is the location of his ship. An air craft, flying above the clouds or through fog, can discover its position by a slightly different application of the radio com- . The pilot sends a wireless message to two ee fields, some distance apart. A com- pass at each field determines the line from the field to the flying plane. Its position—where the two lines cross—is figured out on the ground and radioed to the flyer. In practically all important lighthouses along the United States coast radio beacons have been established. Each sends out a char- acteristic dot and dash signal which identifies it to any vessel. During one month, they transmitted approximately 200,000 radio com- pass bearings to ships and air craft. ‘THE compass also prevents collisions in fog, for the pesitions of near-by ships can be de- termined when they cannot be seen. The latest development is a miniature radio beacon transmitter which can be wheeled about the deck of a ship, plugged in to its current supply, and made to transmit a characteristic signal warning to other ships in the vicinity. Landsmen, as well, may soon benefit from the use of the radio compass. Tests are now being carried on by the Navy Department, in Washington, D. C., to determine the approach of storms by its use. The compass shows the point from which static comes with greatest intensity, indicating the seat of electrical dis- turbances from which storms may be expected. Future years undoubtedly will find this won- derful instrument of rescue performing still wider services.

POPULAR SCIENCE MONTHLY 137

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POPULAR SCIENCE MONTHLY

PLASTIC WOOD? Reg. U.S. Pat. Off. The North Wind doth blow, and keeps blowing right through the edges of the window casing. Stop the drafts with Plastic Wood—force it in the cracks around the frame. No matter what the house construction—wood, tile, brick, stone—-Plastic Wood will hold permanently fast. It handles like putty and hardens into wood. Use it for cracks around the base- board, too—under door sills, in floors, in doors—wherever the cold air seeps in. It is waterproof and weather- proof, and takes paint or varnish per- fectly. PLASTIC WOOD {Reg. U. S. Pat. Off.] It is a product even a child can use for an in- finite variety of permanent repairs, indoors or out, wherever new wood is needed around rot, cracks, splinters or holes. It is particularly useful for holding loose casters and drawer pulls. The realistic and amusing figures in Mar- ionette shows are largely made from Plastic Wood, it so easily lends itself to moulding of all kinds, from picture frame repairs to articles of pure amusement. Plastic Wood Solvent When working, it sometimes is desirable to soften or thin Plastic Wood, and because of its adhesiveness it will stick to tools or fingers. To soften or remove it use Plastic Wood Solvent. in 25 and 50 cent cans. Handles like Putty 1 Ib. can $1.00 At Hardware and Paint Stores ADDISON-LESLIE COMPANY 314 Bolivar Street Canton, Mass.

Witches— Still on the Job! (Continued from page 45) old German word “hagadisse,’’ meaning spirits in female form. In Germany it became shortened to “hex,’’ and in the tongue of the Anglo- Saxons, who took it with them to England, to the word “hag.” Africa is still under the spell of witchcraft. The witch-doctor is an important personage, doing a thriving business in charms and in- cantations. Professor Clark Wissler of the American Museum of Natural History says that witchcraft is still practiced among the South American Indians living along the banks of the Amazon river, among people in southern Europe,India and Australia, and among Indians in parts of North America. For believers in witchcraft the power of suggestion is such that it may lead directly to the death of one who is convinced that he has been “hexed.” Sixty percent of the deaths among the natives of West Africa are believed to result from belief of the victims that an evil spell has been cast upon them. In Haitiand among the negroes of the Mississippi Delta the “voodoo” is still all-potent. ITCHES work in divers ways, but al- most everywhere they demand some object which the victim has worn in order to cast an effective spell. A lock of hair is con- sidered the best of all. To ask an Eskimo for a lock of his hair is to court death, for it can be wanted for only one purpose, that of bewitch- ing its owner. There are many tests for witches among tribes which believe in them today, similar to the test used in Europe only a couple of hun- dred years ago. Matthew Hopkins, England's most famous witch-finder, who was at last hanged himself for witchcraft, had certain defi- nite means by which he claimed to determine whether a person was a witch. Sticking a needle into the body was one of them; if the victim felt no pain he was a witch! Inability to shed tears or to repeat the Lord’s Prayer as well as the practice of walking backward or against the sun, were considered other signs. One test was to place the accused witch in one scale of a balance and a Bible in the other; if the ac- cused weighed more than the Bible, he or she was certainly a witch! Women were sent to the gallows on.no stronger evidence than that, as late as 1712. In India today a test of the witch is the or- deal by fire; if one is innocent of witchcraft the fire will not burn him. Another test which seems to be used wherever witchcraft is be- lieved in is to tie the accused’s right toe to his or her left thumb, the left great toe to the right thumb, and cast the witch into the water. If he or she sinks, innocence of witchcraft is proven, for water will not receive a witch! The net effect on the accused is death in either event. HARMS and incantations against witches are still in use among people who call themselves civilized. When you touch wood after boasting of good health, that is a sur- vival of the ancient superstition that a witch cannot harm you if you take refuge behind a tree. Throwing a pinch of salt over one’s left shoulder after accidentally spilling the salt is another familiar practice, indulged in by many people today, which dates back to the earliest beginning of witchcraft, and so is the habit of the Italian peasant of crossing his fingers to ward off the “ malocchia” or evil eye. When Shakespeare wrote “Macbeth” all the world believed in witches, and there was nothing implausible about the incantations and predictions of the weird sisters. But who would have looked for witchcraft in modern America, in the heart of Pennsylvania, less than a hundred miles from the most thickly

settled and sophisticated part of the United States!

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Aprn, Ih Oca ibrary Fepeee°s 3s ~ fs + as ApRIL, 1929 POPULAR SCIENCE MONTHLY 139 | Switching on the Sun! (Continued from page 27) ns of arc lamps and filling them sat Oe es eubotances When he found the hs t he sought, he continued experimenting. One of his chance discoveries was a light that seated sunshine even more closely than the old type of all-carbon arc. Its source was a carbon fled with the rare earth metal, cerium, into a paste and forced into the black sticks with hydraulic presses. HILE the carbons can be used in any car- bonarc lamp, the maker has added a screen that excludes the few rays that are not found in natural sunshine. The result is a lamp that contains not only the same kinds of light found in sunshine, but almost exactly in the same ions. A chart reproduced here shows the extent of the duplication claimed. Further- more, it is pointed out, some of the extremely short ultra-violet rays, as apparently shown by recent research, have the curious property of neutralizing some of the others’ benefits; they are carefully screened off. Other types of carbons have been developed for special medical uses. They may be used in a home lamp under a doctor’s prescription. One, filled with an iron core, gives a bluish light rich in rays that have been used to treat surgical tuberculosis. Another is used espe- cially for rickets; it is filled with several metals. A carbon cored with the metal stron- tium gives a red light containing heat rays that relieve internal congestion. Once more it should be emphasized that the sole justification of a health lamp in non- professional hands is to keep a well person well. It should never be used to treat sickness without a doctor’s advice. More Elements nm Find ROM W. W. Andrews, of the General Elec- tric Company, recently came the statement that there may be other elements beyond the ninety-two in the accepted list of the “building stones” from which all matter is made. The difference between one element and another is in the number and arrangement of electrons, or particles of negative electricity in each of its atoms. The hydrogen atom has only one electron, the helium atom two, and so on up to uranium, the densest of all known sub- stances, with ninety-two electrons in each of its atoms. There has been no evidence and, until now, no suspicion of substances in the universe of greater atomic weight than uranium yet Andrews points out that the same mathemati- cal laws which led to the deduction of some of the known elements indicate the hypothetical existence of an element which would be No. 118 in the extended scale, and which he calls “hypon,” because its existence is purely hy- pothetical. He imagines hypon as existing under enormous pressure in the core of some sun in outer space. He suggests that the occa- sional appearance of a brilliant star or “nova,” which flames up only to die down in a few months or years, is due to the release of pres- sure on the hypon core of an unknown celestial body, causing the entire star to disintegrate and its electrons to rearrange themselves into other and familiar elements. He holds that the elements which we know may be only the end products of atomic disintegration through the ages, created through just such means. Hypon would be immensely denser and heavier than anything we know. There is ground for belief that in some of the regions of space, elements exist which are so dense that a handful of one of them would weigh on the order of tons if measured on an earthly scale. There is little likelihood, however, of the dis- covery of these elements themselves. . Built upon the Porter lever and toggle joint principle but with an entirely new type of jaws. A portable hand-operated tool that will cut flat bar stock up to 11,’ x9/32’ or stranded wire rope up to 5" in any position anywhere. Jaws cut like shears, leaving no broken edges or no uncut strands. Will not unduly twist or distort material. Makes clean cut at one operation. In capacity, power and portability, no other tool can be compared with a Porter Shear Cutter because no tool heretofore de vised comes within its field of usefulness. One of a Line of Porter’s Portable Time- saving hand-operated cutting tools. Take the tool to the work, not the work to the tool H. K. Porter, Inc., 7 Ashland St., Everett, Mass. Any flat material, 36 inches long to cut 54” wire rope or within capacity lim- 114" x 3," flat stock. These, and all other Porter tools, are sold by leading jobbers and supply houses. The Porter line includes Bolt Clip- pers, Nut Splitters, Shear Cutters, Wire Cutters, Chain Cut- ters, etc. its, may be cut with amazing ease. Bars, straps, guy ropes, hoist cables, airplane struts, cables and rods, control cables, steel strips, metal straps, etc. This tool is made in three sizes—14 Send for illus- inches long to cut 5¢” wire rope or 4%” trated booklet de- x 7," flat bars; 24 inches long to cut scribing tools and 4%" wire rope or flat stock 1144” x3"; __ their uses. — HB ONE DAY éf2ncinc Pays $150 to $300 We furnish everything for een- Monthly Profits vi Ford Auto = inte . & Start your own big business now, batteries. y terms. Moneyback Oy ends. Write to HOBART BROS. CO. Box P-49, Troy, Ohio ONLY $1659 MONTHLY ~ GIVEN fen mcmn santa key ring. Sent without charge, postpaid, anywhere in United States except Georgia, Alabama, Virginia, Mississippi, North Carolina, South Carolina and Florida— PROVIDED you know any children or P - adults with Club Feet, Infantile Paralysis, Spinal Curvature or Hip Disease. Send this advertisement with names of parents and com: addresses; must include street and street number, or rural route number, State clearly which one of above afflictions each patient has and their ages. no key ring sent unless this ad is enclosed with all information Offer expires June 30, 1929. requested. McLAIN ORTHOPEDIC SARITARIUM, 903 Aubert Avenue, Dept. 890-D, ST. LOUIS, MO.

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140 —_——_--——_——- -- oo POPULAR SCIENCE MONTHLY PUT THIS SSS°° HOME, FREE for/0O Days-No Deposit. A New and Improved Workshop Here is a workshop built to a standar most durable in construction—easy and will withstand severe constant service. Try it for ten days at our expense and you will be convinced of its superiority. d of perfection—accurate in operation— to operate. It is absolutely dependable Suitable for Carpenters, Home Workers, Pattern Makers, etc. .Furniture manufacturers use MAC, THE PoPU- LAR MECHANIC Workshop, for making furniture models. Manual Art Schools use it for instruc- tion. Home workers use it for pleasure and profit. Carpenters use it for making r Ss TURNS, RIPS, CROSSCUTS, DRILLS, SURFACES, POLISHES, GRINDS, CUTS SCROLLS. — parts, spindles, chair legs, cabinets. It 1s ideal for making all kinds of furniture. The Lowest Price For Such - a Sturdy, Complete Workshop MAC, Tue PorctaR MECHANIC, represents the utmost in value and dependability. Now you can have an accurate, practical workshop at a big sav- ing. Once you use MAC you will be convinced of its superior qualities. That’s why we want you to try it. A PERFEC EHOP NO AYEAR]| TO PAY MIDLAND APPLIANCE CORPORATION Dept. 420— 219 N. Michigan Ave. CHICAGO, ILL. THAT’S A “WIZ” for cutting WOOD JUNIOR SKILSAW You will get the surprise of your life when you operate this new electric tool that is COMPLETELY SAFE! It has “GUTS” for real work—amazing pow- er, speed, accuracy, convenience. Imagine—this 10 lb. % H. P. Junior SKILSAW does the work of 20 men! It is the fastest cutting saw on the market per pound and per dollar—rips 2-inch plank 12 feet long in 35 seconds! Where can you buy @ powerful elec- tric tool at this price that will actually save you so much time, money, labor? Four sizes to choose from! Plug SKILSAW into the nearest lamp socket in house, garage, or factory—press the trigger—Zip! Your wood is cut, straight, clean. You'll like to SKILSAW rips, cross-cuts, bevels, mitres, grooves. Aiso used as table saw. You must see SKILSAW for yourself! Ask your Herdware Dealer to show you. Write us today for complete information. SKILSAWmc © Dept. D, 3318 Elston Avenue Chicago, Illinois © This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. hand saw—the only | | Advice for POPULAR SCIENCE MONTHLY readers regarding safe and profitable investments. See Page 4. | | Nary a traffic cop! You’ve watched soft fleecy clouds in a blue sky, and wished you could drift upon a cloud bank. Floating over cool quiet waters in an Old Town Canoe is about as near as you can come to realiz- ing that delightful day-dream. No bit of errant thistledown could rest more lightly on the stream. Get away from the dusty road! Enjoy the relaxation of canoeing in an Old Town. Old Town Canoes have the grace and beauty of real Indian lineage. Easy to handle, and perfectly balanced. Priced as low as $67. From dealer or factory. Write today for free catalog. It shows and prices many light, water-tight models. Paddling, sailing and square-stern canoes, extra-safe Sponson models, dinghies and sturdy family boats. Also speedy craft for outboard motors—racing step planes and hydroplanes. Old Town Canoe Co., 1994 Main Street, Old Town, Maine. ‘Old Town Canoes” > APRIL, Igy s SS Running a Skyscraper : (Continued from page 31) dynamos, operating day and night, w; capacity of 1,500 kilowatts. We ened e kilowatt units and one 200-kilowatt. . These are, of course, of different sizes so al the changing electrical loads of the bujja may be taken care of with maximum efficien. | During the night, when there is a smalle 2 mand for light, we switch from the more ®| ful units to the less. The plant is capable g generating sufficient power to operate an a tric street railway or to supply electric Jig) for a city of 50,000 inhabitants, [ft fen. | nishes the power to operate all our elevators_| twenty-seven in number—the lathes jn te machine shop, the heat for 1,900 radiators, the light for our 80,000 bulbs.” “= n the near-by boiler room ten m | faces blackened, were firing the gigantic hell “Forty-two tons of coal go into those hyp. gry monsters every day,” said Mr. Smith, “} harnessed together they could lift a hundre!| Statues of Liberty without straining.” supplied with fresh air. “For the first few floors,” Mr. Smith e. plained, “‘ we operate a ventilating plant whi furnishes a complete change of air in the thre stories underground and the first four above four times in every hour. Fresh air is drayy down from outside the building above th sixth floor and passed through fine sieves anda curtain of running water, where it is washed, In summer, we cool this air by refrigeration, In winter, we warm it by heated pipes.” The twenty-seven electrically-operated de vators are of supreme importance in trans porting the building’s thousands of inhabitants to and from their work, particularly during the rush hours at 9 o’clock in the morning, at noon, and again at 5 o'clock in the evening. Six o the elevators are “high rise” cars: tw6 run to the fifty-fourth floor, with the first stop at the thirty-sixth, and four to the forty-seventh. From the fifty-fourth to the fifty-eighth floors runs a shuttle. In the Woolworth Building you can take the longest and fastest express eleva- tor ride in the skyscraper world. Suppose one should drop? Well, one has never dropped, but if one should, it would land on air. The Woolworth elevators represent a first experience in tapering shafts. If by any chance the hoisting cables of a car should break, the elevator would drop onto a column of compressing air and come to a slow and gentle stop. Yet, even to prevent that experi- | INQUIRED how the skyscraper city yas | loaded with 7,000 pounds, topped by a glass | without spilling even a drop! ence, the elevators are inspected every day. N INSPECTOR made a test some time ago of one of the “high rise’’ cars. It was full of water, and let loose from the forty-fifth floor. The elevator came to a dignified rest The traffic cop of the perpendicular transit lines is John Graham, veteran elevator starter. He controls the movements of all cars and keeps track of them on an electric signal board which tells him the exact position of every cat at every second. Every car has a telephone, 9 that its operator can be in immediate touch with Graham, whether the car is stalled or go ing at top tilt. Naturally, there is a big force of workers i such a building. “Mayor” Smith has a staffal 239, ranging from lowly charwomen to high salaried engineers. Some of the jobs seem, to laymen, dangerous. They aren't, according to Mr. Smith, and yet if an accident occuts there is an emergency hospital with a doctor and a nurse in constant attendance. It’s quite safe to faint in the Woolworth Building, many a luckless young lady has found out. Indeed, with “Mayor” Smith on the job this up-and-down city is perhaps the safest m the world. ———l

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APRIL, gy sini 1929 POPULAR SCIENCE MONTHLY 141 _ = aper | [ p.nning a 44-Mile Tunnel P

(Continued from page 22) wit hte tel in a passa that had been begun on the ) ; te side of the shaft. ’ watt unit opposite st el progressed, other points were

D is bulla siblished at intervals of approximately a 1 effici ing hundred feet. This was accomplished by lin- smalle ing up the wires behind, through the transit 10Fe po de. telescope, and then flopping the telescope over cape on its transverse axis and sighting ahead from ite an ae the other side, using a Vernier scale to estab- ectric light lish the next point within the thousandth of a » Tt fal foot of accuracy. a epee slevators— | Such work must be six times as accurate as ae t done in ordinary city surveying. Its 1D the| ~ must be no greater than one foot out of ators te Jine in a distance of fifty miles! To insure men, thei | against error at the start of the East River tic boiler. | tube, twelve skilled engineers, one after the those hyp. other, descended into the shaft and established Smith, “} independently the third point by lining up the a hundrel | first two wires. The average of their findings vr | was then taken as the nearest approach to ut- most accuracy. + bin FTER the tunnel penetrated under the Smith ey. A river, the difficulties of the alignment | engineer increased. The sighting had to be ‘the the done partly in free air and partly within the d air chambers where the “‘sand

compresse ‘s pe hogs” worked. In carrying the line through bove the a bulkhead into the compressed air chamber, ves anda the transit was set up in the “‘air lock,” the : washed | erry hag — er sag “ — . Pye ually rai enable workers to enter e f d | — auber. The outer door was left open and Look (Sood e I hey ARE (Soo 3 ated ee through it the wires behind were lined up. in trans nw y vena ~~ closed, _ a Thom we . and the door at the opposite end of the loc . i biden i ' a opened to permit the next point to be estab- All twist drills look —This is the best drill ot a lished by sighting out through it. pretty much alike out- that can be made. . Six of It is within compressed air chambers that the side, but under the finish Whether you use drills ‘6 run to real work of all ae tunnel digging —that’s another story. in continuous produc- »p at the es o> Soe ae Seve tbe woe A good twist drill must tion, or drill one hole a seventh typical of the process. ,Three locks, one for 44 Zoo : 7 SMALL TOOLS é th floon material, one for men, and an emergency be designed right so it onan: asses ae month; whether you run ding you lock, led through the bulkhead. At the nose will cut a clean, accu- panes ica a big drill press, or a 3s eleva. of the tunnel was the $40,000 “shield,” the | rate size hole; it must be yee np recy little portable electric "a giant steel hoop with forward cutting edges head Saeibns ; TWIST DRILLS drill h one that protected the workmen from cave-ins. tard so it Pian: t wear REAMERS oe wae must ar uld land It was propelled forward in three-foot stages dull; and it must be wee Ghee drills that are right. : by a circle of powerful hydraulic jacks push- tempered just right so it And Greenfield Drills — ing agian the t-iron shell of th <i gl by any a3 ep ae sev dl d. In the pane Dn won’t break easily. are right. They will make a fine aa monster cookie cutter, the forward end of the There is a tremendous amount of showing for you, as they have for ow a round shield bit into the dirt and rock ahead. engineering research, analysis of others. Most good hardware or mill exp This material was dug out, and the shield | steel, hardening and tempering ex- : das _— ropar ha gree At the end of each push, perimentation behind the scenes, in supply stores sell them or will get SN | esses pulled forward; Siappeasing neon: | Trier to. make the trade mark them for you, Next time ask for h a addition of a new ring, thirty inches wide, to stamped on each Greenfield drill say Greenfield Drills. F hee the iron lining of the tunnel behind. In the ‘S t arn side of each ring a hole, later plugged, allowed oi ot gravel and grout (thin concrete) to be blown . out to fill spaces outside the shell and thus of Won te CANADIAN PLANT trail strengthen the construction. . : CHICAGO GREENFIELD § TAP AND DIE ! Greenfield Tap & Die es: | 13 Se, Ciaten Stress CORPORATION Corp. of Canada, Ltd. ae and KACH ring of the tube shell was clamped in 228 Congress Street, W. acca MASS.. U.S.A. Galt, Ontario boa +d position with heavy bolts. Six rings a day ya was the maximum progress. The total weight of hy the completed iron tube was 17,300 tons. With AP e r Mite | The man who knows Oil uses tail the rings suggesting segments, the finished oe Build a CLOCK of Rory, or al | has the appearance of a huge, mile-long WN e oP earthworm: FREE BOOK = In making curves underground, the en- PR MR iets tanta none 2 | Be cause taff of gineer is given tables that show the offset Heas.” Gives tall ye og hi ah- from the straight line at intervals of five feet. yg their own use—or to sell | It is made by the refiners of the te He determines the straight line and then sets movements and oe eeu making Pace ond, | world’s best watch and chrono- ih on? the center mark of the tunnel to one side in Por your copy. nary tools needed. We furnish meter oil with the same exacting whe accordance with the tables. In the iron shell, Warls all cnscmtled’ recivw, | care. Only the best is good ee the curve is made by the use of tapered rings install, as low as $1.65; others | enough for fine guns, reels and Joctor like those i : . : with chimes at all prices. You | casting lines. It is as essenti: quite L mg ina stovepipe. Usually every seventh make the case, or simply se- | + their well being as the oil in @ 1g, 88 can an inch and a half taper. Because the Cash-in on the demand for | watch. — — ips down under the river, the angle of oe ~ Mantel Clocks. Ban- | If ynable to obtain Nyoil send » iol a and ascent has to be checked with Here's ‘hobby _that. PAYS—in to us direct 35c for handy cans. oat le equal care. A surveyor'’s level gives the angle oars tine or full-time PROFITS! WM. F. NYE, Inc. DD, coer of the slope, and tables tell the engineer what Write for FREE Catalog and Special Blue Print Offer Oil refiners for over half acentury [Bh —gemasss| this angle should be at each point measured. AMERICAN CHIME CLOCK COMPANY Dept. J. NEW BEDFORD, MASS. - u ner . 1 , .

© This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. 4

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‘s all ting at? SIR WALTER Is RALEIGH |; Neitp the Discovered Hou a Good a Pine Can Be” * [. WAS a simple enough hunch— that a lot of pipe lovers secretly craved a milder mixture than they'd been smoking. We gave it to them— literally—a free tin to every man who asked for it. And now so many to- bacco connoisseurs are cheering for Sir Walter that we can scarcely make enough of it. Isn’t it time you too discovered how good a pipe can be? ¥ LIMITED OFFER y (for the United States only) If your favorite tobacconist does not carry Sir Walter Raleigh, send us his name and address. In return for this courtesy, we'll be delighted to send you without charge a full-size tin of this mi/der pipe mixture. Dept. 185 Brown and Williamson Tobacco Corporation ? k Winston-Salem, North Carolina A SIR WALTER RALEIGH Who discovered how good a pipe can be It’s milder POPULAR SCIENCE MONTHLY Slaying the Ice Monsters (Continued from page 53) degree. ¥. This first causes the ice to crack and then to explode. Using thermit is like pouring white-hot steel into a crack in the ice. When the metallic mixture is heated, the aluminum combines violently with the oxygen of the oxide to produce molten metal. The intense heat generated breaks the ice into its compo- nent gases—hydrogen and oxygen—and these form the high explosive’ that blasts out the jams. The flaming gases shoot hundreds of feet inte the air while the frozen masses are rent asunder. In the days when TNT and other high ex- plosives were used in attempts to destroy ice- bergs, the work of the coast guard cutters’ crews was filled with the thrills of constant danger. In small boats, the crews would row up to the bergs to lay the mines. When a berg could not be approached closely because of dangerous overhanging ledges, the mines were tied to floats and sent to drift against their mark. HE methods used by Dr. Barnes in his thermit experiments on icebergs were of an entirely different nature. Equipped with spiked shoes, Alpine axes, and life belts, he and his party approached the bergs in a motor launch, towing a dory in which the thermit had been packed. Three bergs were selected for the tests; the largest of them 500 feet long. The party, by means of scaling ladders and their axes, cut their way up the slippery side of the berg. Once on its center, a hole was drilled. Then containers of thermit were hauled up by ropes and the charges laid. Time fuses were attached to them. Charges weighing about 100 pounds proved the most effective. The time fuses were fired and the party quickly drew off in its launch to watch the re- sults. Ominous rumbling and crackling was heard. Suddenly, a flame shot 100 feet in the air! In a few minutes, the center fell out and half of the berg crashed with a roar to the water. The same procedure was repeated until each of the three bergs was destroyed. In all, a ton of thermit was used in the tests. Within a few hours a jam of about 250,000 tons of ice was plasted out by three ninety- pound charges of thermit at Waddington, N. Y. At Oil City and Franklin, Pa., an enormous jam, twenty-five miles in extent, was broken up in this manner, without damage to property, in ten days. And at Chimney Island, Ogdensburg, N. Y., a million tons of ice was blown apart in nine hours with only two ninety-pound charges! AT LANTIC icebergs, however, offer a more difficult problem. Often they are of tremendous size. Last year, the Tampa en- countered a berg sixty-five feet high and 1,690 feet long. The officers calculated that it con- tained 36,000,000 tons of ice! The tallest berg sighted by the patrol in years was 248 feet high! And the main bulk of the icebergs is always under the water. The depth of a berg seventy- five feet high is about 300 feet. Last season a procession of bergs, turning like a great merry-go-round of the sea, was one of the strange sights encountered by the patrol boats. A swift, narrow stream of icy water, running along the Grand Bank—a 500,000- square-mile submarine plateau off the coast of Newfoundland—and meeting the warmer cur- rents from the south, formed the vast whirlpool. Single whirling icebergs, like giant dervishes, are seen more often. In the course of six weeks, one berg was carried by an ocean eddy in a circle whose diameter was more than fifty miles! The time may not be far off when collisions of vessels with icebergs will be almost unheard of. Then, instead of sailors patrolling the frigid seas to keep track of the monsters, experts will penetrate the north to blow them to bits. It’s so easy to solder , free sample proves it Like magic! Kester Metal Mender so easy todo. It is a solder with the flux ites in the core. Only heat is needed. With Dah can do a professional job of repairing or makinpae” thing of metal—in a jiffy. No need to wait = repair man—do it yourself with easy-to-use Kee — or ge Lael poe yr auto ACCESSORY, ele trical supply, general and other stores i 4 handy metal ie. sell i int A sample of Kester re r e 4 Metal Mender will be sent on request. See for yourself how easy it is to solder. KESTER METAL MENDER The Household Solder CHICAGO SOLDER COMPany [Est. 1899] 4204-05 Wrightwood Ave, Chics insignia on wings, me = in colors. Construc- tion set includes ready-made aluminum propeller, shaft, band motor, stream-line wood wheels, pre-cut balsa ribs other parts, with clear directions. Canbe assembled in3 ‘ @ average 14-yr. old boy, without tools. Complete set, breakable mailing tube, only 75c, postpaid in U. 8. money order today (no stamps). Print address plainly. or money refunded. . LOGAN TOY WORKS, 35 E. Gay Street, COLUMBUS, 0, (We cannot make C.O.D. shipments. No retail catalogue tem) RAISE CHINCHILH FUR RABBITS cen and pay you following prices for. Chinchillas a each — Toa head SS page il! zine, tells how to onan 3 = cone ot 10c, ise yi or Dig pr: i. ‘or OR ENTERPRISE CO. ot, ouTbooR -. Boy 1922 Holmes P. POPULAR CHEMISTRY A Monthly Chemical Magazine Latest chemical news, experiment, formulas, recent advancements in me cine, new uses for X-rays, ultra-violt light, radium, etc., every month, i Three trial copies (back issues), 9 cents. $1.50 per year. Free POPULAR C=] C2) CHEMISTRY 4 chart and book catalog to immedis yearly subscribers. POPULAR CHEMISTRY SOMPA Dept. A. D. Swedesboro, N.J. BURN YOUR NAME ON TOOLS with THE r R AF ARK Protect Your Tools FromTheft. write with elec- tricity any name or design on the hard- est and finest tools and instruments,or any metal, like writing on paper wi SP so pencil. Comers, 2 aoe ing illustrated Souler tree: Write to- . Agents wanted. ARKOGRAF PEN CO. 1171-A East Stark St., Portiand, Oregon The Midget “‘Five-in-One’”’ Slide Rule MEA RS ag ee od oe ic, Log-Log, % Fe ee aie e in tactantly subtract, multiply and divide any bination of whole numbers CO.. Stuart. Florida (Patented 1-17-22) era >)llUlleellttisid 2e\c\. _ sare \-\ SA | ee ee ee

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ApRiL, 1929 POPULAR SCIENCE MONTHLY Ales THE KING OF THEM AL 4 [ R-CON| A Real Man’s Workshop The Ar-Con Utilitool is not a play- thing. It is a big, strong, accurate and efficient outfit that will bring com- lete and lasting satisfaction to you. From the 4% HP, ball-bearing, repul- sion-induction type motor—the most efficient type built—to the wing screws and lock nuts of drop-forged steel, every detail of the Ar-Con Utilitool is designed and built to assure an ample margin of power and strength, and the maximum of accuracy and depend- ability. Here is the workshop you've always wanted, but never before could find. And you can buy the Ar-Con Utilitool complete or any of the units sepa- rately, on remarkably easy terms. You owe it to yourself to find out about the Ar-Con today. Just write your name and address in the margin, tear out and mail to THE AR-CON TOOL COMPANY 500 Fassett Street—Toledo, Ohio WHY NOT Be Comfortable kg Ease and Relaxation Never Felt Before HOM IF YOU LIKE TO READ, here is a convenience you have long been looking for. Now youcan sit back in your fa- vorite chair, adjust the Mitchell Lap Table to exactly the proper position, and read nsolid comfort! No eye-strain. No tedious holding of the book or magazine, Your body muscles are at rest; your energy is ar! o concentrated on the message before you. an One of life’s most pleasant recreations is empacialty made even more pleasant! fhe Mitchell adie, DOZENS OF USES eye-strain— Read or breakfast comfortably in bed. eat comfortably. Write, figure or draw in your coziest chair. A blessing to invalids; a distinctive and useful gift. Size of panels, 12x18in. Beauti- fully finished; substantially made. Felt bot- tom prevents slipping, protects furniture, 9 Send no money. Try the Mitchell Table MEN for five days in your own home. If not de- lighted, return the table; otherwise, send now us $6.56, and it is yours for a lifetime of v need: service! The coupon is for your conven- their coziest chair. ience. Won’t you send it in today? fh Mitchell Moulding Co., Dept. 2304, Forest Park, Ill.} j Send me, postpaid, a Mitchell Lap Table in 1) Mahogany 4 10 Walnut Finish, complete with two book clips and de- 5 tachable metal supports for bed use. Five days after re) i it, I will either return it or send you $6.50. j Name t {Street Address ! ' City. State ! Here Are Correct Answers to Questions on Page 60 1. Broadly speaking, chemistry deals with what things are made of, while physics deals with the properties or qualities things possess without regard to chemical composition. But there are many scientific problems which in- volve both chemistry and physics, so there is no sharp dividing line between the two sciences. 2. A vacuum is emptiness. When we say a vacuum exists inside a bottle or in regions be- yond the earth’s atmosphere, we mean that, so far as we know, the bottle or the outer region contains nothing we can measure in any way. That would be the meaning of the term if we could create a perfect vacuum. Actually, no perfect vacuum is known to man. The best vacuum we can obtain by the most advanced methods still contains large numbers of gas atoms. 3. Both alcohol and mercury expand when heated, so if you put either of these liquids into a bulb opening into a narrow tube, a rising temperature will expand the liquid and force it up the tube. The sensitiveness of the ther- mometer to temperature changes can be regu- lated by the relation of the size of the bulb to the diameter of the hole in the tube. The larger the bulb and the smaller the hole, the greater will be the liquid’s rise for each degree of change in temperature. 4. Both are heat engines. In the steam engine, the heat energy in the fuel is first transformed into the energy of compressed gas by heating water until it becomes steam. The steam pressure then acts to move the piston in the engine’s cylinder. In the gasoline engine, the fuel’s heat energy is converted into the energy of compressed gas in the cylinder itself by ex- ploding the mixture of gasoline and air. 5. The motion of any point on the water’s surface, when a series of waves passes that point, is up and down. The surface water does not move in the direction of wave travel except, of course, in exaggerated cases where waves curl over and break on top. In a sound wave, on the other hand, the motion of the air atoms is only in the direction of the wave, so that a sound wave consists of a series of areas where the air is slightly compressed, alternating with a series of areas where the air is slightly rare- fied. 6. Water does not run uphill when you siphon a liquid from one tank to another. It appears to do so because it flows up the pipe above the level of liquid in the container from which you are doing the siphoning, but actually it is being forced up by air pressure. A siphon will not work unless the discharge end of the pipe is below the level of the liquid being siphoned. The down-flowing column of water, being longer than the upflowing column, weighs more, so that the pressure at the top of the pipe is less than the weight of the upflowing column. Atmospheric pressure therefore forces water up the pipe. 7. It has been found that an extremely thin sheet of gold, if held before a strong light, will allow a small amount of greenish light to pass through. 8. The energy of the gasoline is first converted into heat to expand the gases that drive the piston. The mechanical power thus developed moves the car along the road and, in doing it, friction develops in the bearings and also in the tires as they roll along. Only a small portion of the theoretical energy in the gasoline is turned into mechanical power and, at the end of the ride, practically (Continued on page 144) 143 sesennneeeeny Pin a Dollar bill to this Patent appl d. for Valve-and-Cotter-Pin Tool of forged steel. It will insert — spread — pull out cotter pins. And slip in washers like a flash. 9%” long. Worth your last dollar as a Shop-help: One dollar with the Coupon; one big money’s-worth. Clip and sign for this latest tool-hit of The SPEN' CER N GS & Compan BIL ee Conn. USA. . New York: It Park Place Chicago: 565 W. Washington Blvd. COUPON To The Billings & Spencer Company, Hartford, Conn: Send the new Valve- and-Cotter-Pin Tool (for $1.00) to— © This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8.

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Five prong tube of the separate heater type operating di- rectly on alterna- ting current. CeCo Announced Type AC-22 Screen Grid Tube —now recognized as the most outstandingly successful ampli- fying tube of the season. CeCo pioneered—and did its pioneering without the fanfare of trumpets. But it is pleasing to know that an increasing number of radio engineers and experts look with confidence to the CeCo laboratories for each new development in the tube industry...a reward not meas- ured in dollars and profits. Do not miss CeCo’s entertaining radio broadcast each Monday evening at 8:30 Eastern time (7:30 Central time) over the Columbia Broadcasting System. CeCo Mfg. Co.,Inc., Providence, R. L “Care Tuber POPULAR SCIENCE MONTHLY Here Are Correct Answers to Questions on Page 60 (Continued from page 143) all of the power actually developed has been wasted in the form of heat. 9. The light-sensitive photographic plate is coated with a layer of gelatin containing silver bromide. No one knows exactly what light does to silver bromide. Chemical analysis be- fore and after exposure shows no change, but the area of bromide acted on by the light is re- duced by the developing agent to extremely fine particles of metallic silver, while the de- veloper has no effect on the bromide that has not been exposed. 10. “Cold light”’ is the term scientists use for light not accompanied by heat waves. Some day, when we have learned how to manufacture cold light, our lighting bills will be but a small fraction of what they now are, for even with the most efficient lamp we have today only a fraction of the power fed into it is converted into light waves. The rest is wasted in heat. Test Answers—See Page 52 OMPARE your answers to the fifty statements in the test on page 52 with those listed below. If all your answers agree, you are a pronounced ex- trovert. If twenty-eight or more agree, your tendencies are extrovertal. If twenty-eight or more are in disagree- ment, your tendencies are introvertal. 1. Yes No 26. Yes No- 2. Yes No 27. Yes No 3. Yes No 28. Yes No 4. Yes No 29. Yes No 5. Yes No 30. Yes No 6. Yes No 31. Yes No 7. Yes No 32. Yes No 8. Yes No 33. Yes No 9. Yes No 34. Yes No 10. Yes No 35. Yes No. 11. Yes No 36. Yes No. 12. Yes No 37. Yes No- 13. Yes No 38. Yes No. 14. Yes No 39. Yes No . 15. Yes No 40. Yes No 16. Yes No 41. Yes No 17. Yes No 42. Yes No 18. Yes No 43. Yes No 19. Yes No "44. Yes No . 20. Yes No 45. Yes No- 21. Yes No 46. Yes No 22, Yes No 47. Yes No 23. Yes No 48. Yes No 24. Yes No 49. Yes No 25. Yes No 50. Yes No Study Radium Poisoning EVENTY-FIVE physicians and industrial | workers met in Washington, D. C., a few weeks ago to seek means of preventing radium poisoning among workers painting luminous dials on watches. Because a majority of the workers who were poisoned in New Jersey are believed to have “eaten”’ the radium by point- ing their brushes with their lips, one suggestion was that brushes be supplanted by a stylus. Studies are planned to determine what sort of health characteristics are best suited to working with radium paint. APRIL, 199 A Better Receiver Cannot Be Built or Bought, than ~The 1929 A. C. Victoreen The Master Super Heterodyne a en a hy mt i . ae + gt There is absolutely nothing that yoy can ask of a Radio Receiver that the Vie does not give. And—it is a proven fact despite the marvelous factory built set available today, you can still build better than you can buy. When you build a Victoreen you have thy absolute satisfaction of knowing that is nothing better made. You also have th. satisfaction of knowing that improvements as they are developed, can be added to, Victoreen Super Heterodyne easily, and y small cost. Just as the Super Heterodyne is the mast circuit, so is Victoreen the master “Super,” If you want*the best you must have the Victoreen. Blue Print, giving full constructional details, Free Write for complete Catalog of Victorcen Products, © THE GEO. W. WALKER COMPANY Merchandisers of Victoreen Radio Products 2825 Chester Avenue’ Cleveland, Ohio | wish theyd Ww Broadcast so-and-so Why wish—flip the switch on a Carter Radio-Phono attachment and your favorite phonograph records will come floating over your radio, sweet and true. No rewiring! necessary, installed instantly. Free folder gives details. CARTER RADIO COMPANY 300 S. Racine Avenue, Chicago, IIlinois Carter Radio Co. Ltd., Toronto Carter Radio Phono Coupler For AC and DC Operated Sets List Price $2.75 © TO PICK-UP avo VOLUME CONTROLS, g ~~ 2 = GEARS All Kinds-Small The most accurate made and prices res; sonable. a complete line of ears in stock for immediate shipment. Gan also quote on special gears of all kinds. Send us your inquiries. Write for Catalogue 214 CHICAGO STOCK GEAR WORKS 105 South Jefferson Street Chi £55 . 22 SSS FER SE So BRET lesu oy 4ore

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"RIL, 199g Annot than ~en dyne at you ) Vieto > | Tact t built as, lild bette, u have that thee > have the Ovemen dded re ly, and a he master “Super,” have the etails, Free roducts, CER Aprit,, 1929 ei 1 Am Learning to Be a Flyer (Continued from page 30) about steering. None of them had said it was a must remember that every time you the rudder, you must move the stick. If should turn the rudder without tipping or ‘ng the ship, it will slip. The worst mis- take you could make would be to bank the ship one way and give it the rudder the other way. jsno easier way to send a ship into a spin. “Now I will explain what these controls do when you work them. Take the stick. Glance out at the wing surfaces. At the rear edge of the wings, out toward the ends, you see that a narrow strip of the wing has apparently been cut away and put back with hinges. Those strips are called ailerons. When you push your stick to the right, the ailerons on the right wing go up, those on the left wing go down. With the ailerons you correct your ship when it is struck by up and down air currents, and with the ailerons you bank your ship when you wish to make a turn or a sideslip.”’ INTERRUPTED: “Why would you delib- I erately sideslip?”’ “Sideslipping, Jordanoff answered, ‘is one of the quickest ways to lose altitude. Toward the end of your course you will learn tc make sideslip landings. They are useful sometimes in landing in a small field or when the wind is not just right. Now, if you will look back, I will explain the elevators and the rudder.” { turned around and looked down the blue fuselage at the ship’s tail. “The flat horizontal surfaces on either side of the rudder,” said Jordanoff, “are the ele- vators or flippers. The surfaces to which they are attached are the stabilizers. The stabilizers are not controlled by the stick, but are set before—or during—a flight according to the weight carried. Watch the elevators. Pull your Idid so. The elevators went up. “‘ Now push it forward.” I obeyed. The elevators went down. It really did seem absurdly simple. When you pushed the stick forward, the flip- pers went down. The air striking them would naturally make the tail go up and the nose go down. “Now the rudder.” That was the simplest of all—on the ground! When I pushed the right pedal, the rudder swung to the right. When I ushed the left pedal, the rudder swung to the t. ORDANOF*F next explained the instrument board. It contained an ignition switch and two dials, an altimeter, which registered alti- tude in hundreds of feet—the needle was now at zero—and a heat gage. Pasted on the instru- ment board was a typed warning: THIS IS AGOOD MOTOR. DON’T ABUSE IT! CRUISE gh 1,300 and 1,400 RPM. “This motor,” Jordanoff explained, “is wa- ter-cooled. Down on the left side near the floor you will find a little lever which works the shut- ter on the radiator. This particular motor works best at a temperature of 160 degrees. Just above that lever you will find another.” I found it—a steel lever with a small rubber handle working in a quadrant. “That is your throttle. It corresponds to the accelerator on an automobile. When you push it forward, it feeds more gas; when you pull it , it feeds less gas. Now—do you under- stand everything?” I nodded, but I wasn’t sure. It didn’t seem possible that the operation of an airplane could be so simple, so understandable. Jordanoff was standing on an aluminum foot plate on the lower wing. He had an envelope in one hand, a pencil in (Continued on page 146) © This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. POPULAR SCIENCE MONTHLY Day-Fan _All-Electric Radio , presents expert testimony to its quality .. . the Institute’s O.K. The scientific test comes to the aid of puzzled radio buyers. Without prejudice, without favor, science in the person of Popular Science Institute engineers accurately measures and records the elements of a receiver’s performance . . . studies its design . . . examines its construction and workmanship. And the safest and surest guide for the buyer of radio today is the report of the Popular Science Institute of Standards. Day-Fan Radio has received the complete approval of the In- stitute. Its fidelity of tone, selectivity, sensitiveness, correctness of design, and construction all measured up to the Institute’s high standards. This is a set that you can buy with full confidence in its reliability. Once you try it, you will not need the word of the Institute for its marvelously beautiful performance—that is evident at once. - Two of the most popular Day-Fan models are shown below. The receiver has nine tubes (including rectifier) with four stages of radio frequency. Consolette (left) and the magnificent Egyp- tian style Console each have built-in dynamic speaker. Day-Fan Electric Company Radio Div., Dayton, Ohio (j Day-Fan Electric Co., Radio Division, Dayton, Ohio: Please send me literature on Day-Fan Radio and tell me where I can hear a demonstration.

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Yordarson Supreme Musical Performance “Built to xceed Your Expectations’ | A # Bailie | Thordarson Be. have been chosen for incorpor- ation in Federal Ortho-Sonic Radio sets because we | have al been certain that we would receive a —_— of product entirely in keeping with the high set by us for Federal receivers. Ket % Picte. President, Federal Radio Corpooration IS significant that the manufac- turers of the world’s finest radio receivers have almost universally turned toThordarson fortheir power supply and audio transformers. Thordarson power supply trans- formers exhibit an efficiency of design, an abundance of power and a constancy of performance that practically eliminates the necessity for service calls. Thordarson audio transformers provide a fidelity of tonal repro- duction that renders the finished receiver a musical instrument of the highest calibre. If you seek the ultimate in radio performance, insist on Thordarson transformers. THORDARSON ELECTRIC MFG. CO. Transformer Specialists Since 1895 Huron, Kingsbury and Larrabee Streets CHICAGO, ILLINOIS THORDAR ARSON TRANS? Oo MERS SUPREME IN MUSICAL PERFORMANCE POPULAR SCIENCE MONTHLY I Am Learning to Be a Flyer (Continued from page 145) the other. On the back of the envelope he drew three lines, as follows: On the upper line, he marked 90; on the middle line, 60; on the lower line, 0 “The me oe line,” he explained, “is your maximum climbing angle. When you climb at that angle with the throttle wide open, you are using the full horsepower of your motor. When you try to climb at a greater angle, you are giving the motor more work than it can do, and the ship stalls. “When you are flying horizontally—the middle line—you will use, for cruising, sixty horsepower—perhaps a little more or less. “The lower line is your gliding angle. At that angle, your motor is throttled down and you are using, theoretically, zero horsepower. “Just below your instrument board on the right you will find an iron handle about three inches long. Now it is pointing straight down. With it the gas is turned on or off. Down is off. Pull it up slowly until you feel it click.” I did so. The handle was now horizontal. “Did it click?” “Yes, sir.” “THE gas is now on.” He called to a me- chanic, who went to the propeller. “Gas on. Switch off,” said Jordanoff. The mechanic began slowly turning the pro- peller. He must have turned it a half dozen times—pumping gas into the cylinders. He stepped back and shouted: “Contact!” . “Contact!” Jordanoff repeated, as he reached in and turned on the ignition switch. The mechanic gave the propeller a jerk. It swung back and forth but nothing happened. Jordanoff turned the switch off. ‘Switch off!” called the mechanic. **Switch off,” Jordanoff repeated. I recalled what the Department of Com- merce doctor had = in examining my ears. The first purpose of a flyer’s ears, he said, is to hear clearly when a bce 2b says “‘Switch off” and “Contact.” If the switch were left on when he twisted the propeller, the motor might start up. To be struck by the blade of a whirling airplane propeller is almost certain death. All over Curtiss Field are signs: KEEP AWAY FROM THE PROPELLERS! Presently our motor sputtered, coughed, and roared. A blast of wind swept into my face, in spite of the thick celluloid windshield sens the cowling in front of me. Jordanoff had his hand on the throttle. He was pushing it forward and back, racing the motor, slowing it down. He reached into the forward cockpit and pulled out a worn old hel- met from which dangled six or eight feet of flexible metal hose. He explained that the hose was a speaking tube. The tube forked; one fork ran to a little disk sewn into the helmet over the approximate position of each ear. At the other end of the tube was a rubber mouthpiece. Through this tube he could talk to me, above the roar of the motor; but I could not answer. It didn’t seem quite fair. ITH the motor throttled down, we could still talk by raising our voices. Jordanoff asked: “Do you know what makes an airplane fly?”’ Tanswered: “‘I think (Continued on page 147) © This seal on an advertisement ia POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. Buia Your Scale Model Airplane the IDEAL way! DEAL Models are accurate, be uction copies of famous Airplanes; perfect ph in appearance and construction details, many realistic parts and fittings not found other models. They make long, perfect ts and are controllable by movable ailerons, and rudder. Build an IDEAL Model—it's easiest, quickest and safest way to construct a strong, reliable Model thatis guaranteed to fly correctly, “SPIRIT of ST. LOUIS” shown above. 3.f tae. 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Send us your order with check attached or pay postman upon delivery We pay all the mailing c There is no choice. You must use Amperite to automatically control variations in the “A” current supply to your tubes. . A for every tube—A.C. = orb. $1.10 with moun’ iS OQ ARadiatl Company. 50 FRANKLIN ST., a am 9 Write Dept.PS4 Blue Book” : = $ Jewel Cyl. Men’s Wrist Watch. Limited Time Only ‘4% sug watoh is a six and not a one-jewel cylinder. Worth 00. maine leather strap. Radium dial, tells time in dark. » Tichly engraved. Rush your order. Quantity lim- no mots Readall importing Co Box C. South Station Fall River. Mass. A definite program for getting ahead financially will be found on page four f sttyne of this issue. POPULAR SCIENCE MONTHLY I Am Learning to Be a Flyer (Continued from page 146) so. The air from the propeller pushes back- ward. That makes the plane go forward. In going forward, the wind against the slanted wings makes them lift the plane off the ground and keep it in the air.” “Not quite,” said Jordanoff. “The wind shooting past the wings creates a partial vacu- um on their upper surfaces. This vacuum per- mits atmospheric pressure literally to support the plane in the air. Ninety percent of the ‘lift’ is atmospheric pressure. Only about ten percent is due to the rush of the air against the under side of the wing. Are you strapped in?” I wasn’t. I hadn’t even seen a strap. I found it now—two ends of a stout web strap. The buckle consisted of a hinged curved bar of steel and a steel ring. You hooked the bar through the ring, snapped it back, and it stayed that way despite tugs and jerks—until you un- fastened it yourself. Jordanoff was climbing into the forward cockpit. Then all I could see of him was his head. The motor roared. A mechanic brace himself against the left lower wing, to aid us in making a sharp turn out of the line. The motor foared in bursts. We were bump- ing along the ground with a great deal of noise. Except for the motor’s roar, we might have been bumping along a bad country road in.a farm wagon. Jounce! Bang! Crash! We were taxiing to the end of the field. I was on my way to my first airplane ride, my first flying lesson! But I wasn’t as nervous as I had expected to be. I had expected to be numb with fright. But my senses weren’t working very well. 1 heard the roar of the motor, felt the jouncing, and saw things going past. My vision was blurred. My stomach felt tight. I recalled what one of the advanced students had told me: “Wait till he holds up his hands the first time, to show you you have full control! Your stomach will cuddle right up to your tonsils!” E REACHED the end of the field, made a sharp turn into the wind, and stopped. The motor was idling. A voice, deep an: foreign, boomed into my ears: “When I ask you a question, shake your head for no; nod it for yes. Nod if you under- stand, shake if you do not. Is your motor hot enough?”’ He was looking back at me. I looked at the gage. It was 160. I nodded. “Is the radiator shutter closed? If so, open ~ gf I reached down and pushed the little lever forward. “*Keep your hands and feet clear of the con- trols until I tell you.” He looked back. I understood. I nodded. Jordanoff seemed to settle down. I tried to relax. I said to myself: “‘Don’t forget. Always relax.” The motor roared. We began to move. It was just like taxiing. Except that, by imper- ceptible degrees, I discovered that we were no longer jouncing. The brown grass was flying by beneath us. Suddenly something else flew by beneath us. I recognized it as a hangar. That was what the first few seconds of flying were like—to me. I had no sense of leaving the ground. The ground merely left us. UDDENLY I was looking down the right wings at the ground. That was a bad mo- ment. I knew that we were banking, turning. I knew that I must follow the ship through, no matter what maneuver she made. But I found myself stiffening, longing for her to be back on an even keel. Presently she was, but my stomach was high within me and shrinking. Everything was blurred and confused. The propeller was blcew- ing a winter gale in my face. I looked at the altimeter: 200 feet. (Continued on page 148) Television Reception This lam is made in numerous types and styles, which provide suitable light sources and light- sensitive relays for all systems. List Price, #7 59 Television Sending This is an extra-sensitive broad- casting tube, supplied in either hard vacuum or gas-filled types, and in two sizes of each. Information and prices on application 7 Raytheon BH ~ Lonc LIFE RECTIFYING TUBE ~ “B”? Power Eliminators Over a hundred different makes of ‘“‘B”’ Eliminators require this tube, and take no other. There are millions of them in daily, satisfaction-giving use. List Price, $4,-50 Write for further information on any of this equipment RAYTHEON MFG. CO. CAMBRIDGE, MASS. @ This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8.

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148 KeepYour lools Sharp Wirth the OF Vaeleyabbacelb iin Sharpening Stones Use them on chisels, plane bits, draw knives, scrapers, gouges, hatchets, etc. There is a Carborundum Sharpen- ing Stone for every edge tool from an axe to a razor. Made of genuine Car- borundum, the manufac- tured abrasive, the hardest, sharpest, fastest- cutting material known. THE CARBORUNDUM COMPANY NIAGARA FALLS, N. Y. fenegs- the Soond Trade Mark of Carborundum for its Sil and is its exciu- \sive property. © REG. U. S. PAT. OFF. Abrasive Products Tue CARBORUNDUM COMPANY P. 8. M. +9 N1aGaRA FALLs, N. Y. Please send me your booklet: ** How to Sharpen Wood-Working Tools.”’ Name Address City ’ on her course. POPULAR SCIENCE MONTHLY “T I Am Learning to Be a Flyer (Continued from page 147) I watched the needle. It was near 1,000 when a voice boomed: “Observe the relative position of the horizon to the nose of the ship. We are no longer climbing. Find out where your horizon belongs and always keep it there.”’ He looked back. I nodded. The ship bumped. It continued to bump now and then. It was similar to taxiing—going over a bump in a bad road. I noticed later— much later—that every time I flew over a macadam road, on a sunny day, no matter how high my altitude, the ship bumped. It bumped as badly at 2,000 feet as at 1,000 or 100. The hot road was sending up an air current. Flying over hills, cities, railroad tracks, and plowed fields, it is generally rough. Over smooth fields, it is generally smooth. The deep voice of Jordanoff: “Place your hand lightly—very lightly—on the stick. Place your toes lightly on the pedals.” Very gingerly I did as I was told. “Follow my movements.” My hand was shaking. Perhaps it was cold. I felt the stick twitch ever so slightly to the right, twitch back to where it was. I felt no movement of the pedals whatever. To my amazement, we were in a sharp bank and turn- ing rapidly. The stick twitched again. Again I felt no movement of the pedals. But we were flying level and straight once more. “TI will now show you what happens when you try to climb too fast.”’ HIS sounded ominous. It was. I felt the stick come back. The horizon sank as our nose went up. It seemed to me we were climb- ing straight up. Suddenly the motor seemed to go dead. It made a strange noise and the roar was followed by an awful whirring. I knew what was happening. ‘‘Chic’”’ Gaver had told me what happened when you climbed at too steep an angle. You stalled. In stalling, you lost all speed. Your ship became, not an airplane, but so much dead weight. We were falling through the air! The horizon reappeared suddenly. It seemed to shoot up. My stomach tightened up a little more. A calm voice said in my ears: **We are diving. The ship is out of control. The controls will not become operative again until we are diving fast enough for the wind to affect them.” I stopped being so nervous. I thought this was great. It occurred to me that the airplane is wonderful. It did things for itself. You climbed too fast: you stalled. The weight of the engine pulled your nose down: you dived. You were presently diving fast enough for the controls to work. It was great, all right—if there was room enough between you and the ground to pull out of the dive! I looked at the altimeter: 800 feet. We were out of the dive, sailing along beautifully on an even keel again. I was thrilled. I could even relax a little. I knew I was going to like flying. The voice of Jordanoff broke into my enthusi- astic thoughts: “You will now take the controls.” HS time my courteous instructor did not look around. I shouted: “Not yet! Wait! Hold on!” But it is useless trying to talk into the blast of ninety horsepower. Jordanoff’s hands were above his head. My right hand was on the stick. My feet were on the pedals. I was flying the ship! My stomach was feebly protesting. It didn’t want me to fly —not yet. I was amazed that the ship continued to fly She should have slid off to one side or gone into a tailspin. The voice: “You are over-controlling.” I relaxed my clutch (Continued on page 149) the World “soa ~~ S — paren. — anda sh see i a iat dine a la ea GUTBQARD meron of strictly up-to-date aan ofa Builts rc — of a racer. s »s' and absolutely safe. ” and Rowboats — and up— The most complete line ever offered, at real saving prices. Cances Ji $48.00 fj and up— Some all wood, others canvas co safe, strong and durable. Ch f ‘st wit, . ie. Choi iF color combinations. ote many ¢ { Motor ie. ae Boats— With or without Engine. Fast, handsome Craft at money-saving prices. CATALOG FREE — SAVE MONEY — ORDER BY MAN, Please state the kind of boat you are interested in (9%) ———> TWO LARGE FACTORIES THOMPSON BROS. BOAT MFG. 219AnnSt. 7 wrinig \ 119 EimSt PESHTIGO H wisconsin Dither Place} New 50 MICROSCOPE "6" Mate mes entertaining, this fine microscope helps all to know life that can’t be seen with unaided eye. Tiny insects look like monsters. Plant and mineral life re- veal new wonders in form and color. Used by stu- dents, dentists, physi- cians, scientists-— in home, office, school and labora- tory. Precise opti- cal qualities. Magnifies 100 to 250 times. Tilting stand, fine finish, nickel trim, plush-lined case, prepared slide, in- structions. At your dealer or direct io stpaid. Money ack guarantee. Other models $2.50 to $8.50. Catalog Free, Wollensak Optical Company 871 Hudson Ave. Rochester, N. Y. AIRPLANE 12-inch , Scale ae ; ea om TTR mo. . Eas 7 built in 3 np os a Pie fe om OF mene y back Send NTON Box E Chillicothe, Ohie B SPORT BODIES FOR FORDS atFACTORY PRICES si Moded i *38= | earings Hi- compression heads p Parts, sia teat : aeons ae D-3 sees : E Breed squabs i make money. cag by millions at higher” prices thal chickens. Write — at once for ore free books ing how to “o | One ts one printed in colors, other 32 pages. ¢ for Books 3 an and 4. oryou will be surprised. PLYMOUTH ROCK SQUAB COMPANY 616 H Steet. Melrose Highlands, Massachusetts. 8 years. Reference, any bank or trust company, © This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. Z 5 s

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ACTUAL SIZE BURGESS SNAP LITE FLASHLIGHT The Vest-Pocket Flashlight (Size: Height 234"; Width 134"; Depth 11") A caseless flashlight that is durable and practical—dainty and exquisite. Lasts an amaz- ingly long time. Silvery, spark- ling color designs: red, blue, green, brown, black. This amazing innovation in flashlights will be indis- pensable to you, once you areaccustomed to its wonder- ful convenience. In your pocket or purse, under your wing ti cota in the garage and . asement . . . you will find - Y scores of uses for this handy —; little miniature flashlight. Its long life is due, partial- x fe ly, to Chrome—the preserva- roupd BY tive which guards power 10 sec when the battery is not in use and which is a patented fea- ture of all Burgess Batteries: radio, ignition or flashlight. BurGcess BaTTERY COMPANY General Sales Office: Chicago Mfrs. of Radio, Ignition and Flashlight Batteries ay Sold in These Stores: fonts DRUG; wee HARDWARE; ~— ELECTRICAL; y. Sold AUTOMOTIVE; higher | DEPARTMENT ; and others. Go to the Nearest One and Ask for It POPULAR SCIENCE MONTHLY I Am Learning to Be a Flyer (CMBbn ued from page 148) on the stick. Then came Jordanoff’s voice: “Your nose is too high.”’ I pushed the stick forward. Down went the nose. “Your nose is too low.”’ I pulled the stick back. When the horizon came to where it seemed to belong, I held it there. “Your left wing is down.” I tipped the stick to the right. Up came the left wing. “You are not flying straight but in a wide circle. Pick out some object on the horizon and fly for it.” I tried to. Have I said that the horizon was very hazy? It was. It was hazy and its haziness was rendered more so by the fact that, in look- ing at it, I was looking through two layers of thick celluloid, the windshield in front of me and the windshield in front of Jordanoff. I saw a dark cloud and decided to steer for it. It was to the left. So I pushed the left rudder. The cloud skidded so far to the right that I lost it. The voice: “Release controls!” I released them gladly. I had given the rud- der too generous a kick. It seemed to me we were skidding. We certainly were! It had taken us just that long to stumble upon my worst fault—my footwork. My feet were dumb. They had utterly no rudder sense. They were probably the dumbest pair of feet that ever went up in an airplane. Further trials only affirmed the same dis- couraging fact. E PRESENTLY returned to Curtiss Field. When we had taxied to the line and the motor was shut off, Jordanoff said: “Not bad at all. Not half bad. Of course, we may have to try flying you with your shoes off until you develop more rudder sense. But perhaps not.” I felt that he was letting me down easy. I was certain that I would never learn to fly. There was little enough to do, but—how well you had to do tha! I had expected to come back from that first lesson trembling with terror. I was trembling, but not with terror. I was mad. Mad at the plane and mad at myself. Mad, most of all, at my feet. It was comforting to learn that most begin- ners come down from their first few lessons mad clean through! OULDN’T you just feel that dizzy skid away up there, as Larry’s “dumb feet’? gave her the rudder? Next month you’ll ride with him again. In his vivid, brilliant, story, this young student pilot will let you share with him more of-the stirring first experi- ences at the controls of. an airplane. It’s too good to miss. Named the ‘‘Best Flyer’’ HO was the world’s best aviator of 1928? The International League of Aviators has just named Col. Arturo Ferrarin, Italian ace, for that honor, which Lindbergh won in 1927. It is a popular choice, based on the longest nonstop flight of history which Col. Ferrarin made last summer from Rome to Brazil. Accompanied by the late Major Carlo P. Delprete, he flew 4,417 miles to establish a mark that airmen of all countries are still try- ing to beat. Previously, he had set a world’s duration record. United States honors went to Carl B. Eielson—pilot with Capt. George H. Wilkins on his flight last year from Alaska to Spits- bergen over the top of the world, and then in Antarctica with Wilkins. HIS engine ona 214-ton truck, froze and burst. Tak- ing down, welding and reassembling at a cost of $150.00, would have taken time and given no better re- sults than produced in a few minutes with Smooth-On. How to repair a cracked water jacket with Smooth-On No. 1 No disassembling and no heat! A. Simple crack. Force Smooth-On No. 1 into the crack and give it a few minutes to metal- lize. B. Long crack. Put the Smooth-On under a :\ metal plate, held with rj © cap screws. C. Piece broken out. Fit the piece back with ¥% , Smooth-On in the break 5 and bind with metal non straps. D. Holes or thin spots. Cut weak metal away, bevel back, fit with manhole 3 plate, and force the tr a Smooth-On in tight =: » with screw. To make an extra neat job,-cut off outer end of screw. Use Smooth-On also for stopping all water, oil, gasoline or exhaust gas leaks and for tight hold at screw threads of nuts, hub caps, etc: Typical home repairs that can be made perfectly with Smooth-On:—Stopping leaks in steam, water, gas, oil or stove pipes, mending cracks, breaks or leaks in furnaces and boilers, ra- diators, tanks, sinks, pots and pails, making loose handles tight on umbrellas, knives, ham- mers, brushes, drawers, etc., tightening loose screws, hooks, locks, door knobs, etc. To get perfect results, write to us for and use the Smooth-On Repair Book. Get Smooth-On No, 1 in 7-0%., I-lb. or 5-lb. tins at any hardware store or if necessary direct from FREE The Smooth-On Repair Book will show you how an astonishing number of home and automobile re- pairs can be made without any particular effort or skill. To get your copy, mail the coupon. Sue Sm SMOOTH-ON MFG. CO., Dept. 58, 574 Communipaw Ave., Jersey City, N. J. Please send the free Smooth-On Repair Book. Seer ee eee eee eee reer ee eee te ee ee ee ee eee ee eee ee ee |

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' 150 POPULAR SCIENCE MONTHLY

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The Real Fathers of Flight (Continued from page 44) going up, the old glider was ready for practice, and the new machine would be worked on during rainy or windless weather. Wilbur, on October 4, wrote to his father that the new shed, forty-four by sixteen by nine feet, was about finished. There had been two days of first-class gliding last week, with the longest flight lasting forty-three seconds, which was a slight improvement over last year and also a world record. Soon, wrote Wilbur, they would raise the record above a minute, for they could now hover almost stationary in a favorable wind. Hovering was a feat be- yond all previous experimenters. Wilbur em- phasized to his father that there was less dan- ger in gliding than before and all precautions were taken by Orville and himself. NOTHER letter from Orville to his sister on October 12 mentioned a great storm lasting four days. It told how the writer, in a twenty-five to thirty-five mile wind whizzed straight up in the air, and in bringing down the glider slammed Wilbur on the head and smashed the wings at one end. Also one wing of the new machine was being completed and to this brief reference Orville could not help adding a touch of exultation in a three-word phrase of children who term anything im- mense or delightful as “‘whopper”’ or “‘ wop- per. I regret that I must abridge for the reader the voluminous Wright letters and diary rec- ords of thousands of words pertaining to their momentous campaign of 1903, a great and thrilling series of unpublished documents that lie before me. One of the best letters, ful: of quips and merry nonsense, decorated with humorous sketches, was written on October 18 by the usually sedate Wilbur to his sister. It tells mainly of a gale that almost wrecked the camp building and sent five vessels ashore along the Atlantic coast, one within sight of Kill Devil Hill. The brothers, abed, feared that their incomplete rocking domicile would crash down on them. Toward four a.m., with the floor partly under water, they hustled to apply interior braces to their structure. Then the tar-paper roofing began to fly off. Orville donned Wilbur’s overcoat and with a ladder went outdoors to mend the imperiled roof. The wind blew him backward some fifty feet, the tails of his coat standing out like wings, as illustrated by the writer’s sketch. Wilbur went to the rescue and helped to set up the ladder. As Orville perched on the roof edge with hammer and nails, he was put in chancery by the wind-driven coat being folded tightly over his head. Another sketch illus- trated his plight, laughable in retrospect but serious enough when it happened. Orville himself said afterward that he could hardly drive his hammer against the savage pressure of that gale. Happily, the camp building was saved. ; Caan TAYLOR, now tending the Wrights’ bicycle shop in Dayton, received a lot of news and banter direct from Kitty Hawk., Orville was the principal source, often cramming several hundred words on a post card. A festive card of October 20 describes their work on the flying machine in the lan- guage of Wall Street: “Stock was quoted at 208 yesterday morning but fell to 110 at noon.” This was due to temporary misbehavior of the old glider. In reference to Charley’s complaint that he felt unsteady on his legs, Orville ad- vised that he brace his legs with the Pratt truss used on the airplane and here is a little diagram to show how to do it! Octave Chanute and his protege, Dr. George A. Spratt, who had (Continued on page 157)

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& Boe S ieee: bit if eS 8 7 a ified | al: SGRENREERE | 2°; mad | 1°28 Apait, 1929 The Real Fathers of Flight (Continued from page 156) r’s performance of the Wright ee been Pivited by the brothers to po camp about November 5 for the expected trial of the power machine. Chanute was a civil engineer of Chicago, a designer of experi- mental gliders, a cheerful Moses who inde- fatigably scouted the trail to aviation’s Promised Land but did not see it when it lay before his eyes! Dr. Spratt was a young amateur who gave the Wrights a useful hint on the reversal of center of pressure, which they verified with their wind tunnel. The doctor came on October 23, Chanute on November 6. It was too cold for the elderly Chanute, although the anxious hosts stuffed rags in all cracks of their building and kept a ing wood fire in a stove improvised from an old carbide can. He left camp, shivering, on November 12. HE power machine seemed under a hoodoo Te bad weather and accidents. There was a lockout of the sole camp employee, Dan Tate, who sojered on his chore of fetching firewood despite his liberal stipend of $1.25 a day when the local wage scale was fifty cents. Dan lost a place in history along with is job. : ‘At the first ground test of the airplane, the steel tubing shafts of the propellers twisted out of shape in a few seconds. “Too bad,”” we may imagine Dr. Spratt’s sympathetic murmur. ** Well, you think Char- ley Taylor can fix them. I think I'll go home —been here two weeks now—though I would like to stay and see the first flight of your ship. On my way home I can express the shafts to Dayton from Norfolk.” “Thanks, Doctor, very good of you,” the grateful Wrights doubtless responded to this offer. The Doctor went with the shafts on November 5. He did the helpful errand and, like Chanute, missed the big show of the third week in December. Charley Taylor in the bicycle shop brazed the cross arms of the old shafts onto new ones of gas pipe. Meanwhile the brothers did some practice sailing with the old glider and hugged the carbide can stove to keep warm. The new shafts arrived on November 21 and two days later Orville wrote to Charley saying he had done a bang-up job of brazing and everything. It was fine that the bearings were not hurt. At the test the engine was pretty jerky be- cause two oil-filled cylinders missed fire and in ten seconds both sprockets for the chain drive worked loose. Well, continued Orville, while there is life there is hope. They just pe standard old remedy for all me- ills, Arnstein’s bicycle cement, guar- anteed to cure anything between a stop watch and a threshing machine. Did it work? Why, it just froze those sprockets in place. Also the engine now performed nobly. Stock in the flying machine was soaring. OWEVER, a sickening accident befell on November 28. The engine was speeding merrily in its test when—smack!—a bit of metal flew off one of the new shafts. Winter was near, two months had been spent in a sandy desert, it was a thousand miles and two weeks’ round trip to the home machine shop. We can see a young man of slight but wir build, a suitcase in each hand, trudging 7 ena’ four miles of ankle-deep sand from a camp shed to the hamlet of Kitty Hawk. He stops to rest on the lonesome, clogging trail. He arrives, takes a boat for Elizabeth City, N. C., there counts the meager bills in his purse, gets a night’s lodging at a cheap hotel, a hearty appetite to save funds, and in i momning buys a railroad ticket for Dayton, BPaeets S| “Not a nickel left (Continued on page 158) Ist Prise........ D4 3rd Prize........ $25.00 4 15.00 FREE Everyone entering a drawing in this contest may have his or her art ability tested free. When your j contest drawing is received, we 7 will mail you our Art Ability Questionnaire. 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This contest is for amateurs only (17 years of age or more), so do not hesitate to enter, even if you haven’t had much practice. 5th Prize 6th to 15th Prizes, ea.5.00 To the Next 50 Best Drawings—A Fountain Pen b pli hicde a $10.00 Rules for Contestants This contest open only to ama- teurs, 17 years old or more. Profes- sional commercial artists and Fed- eral students are not eligible. Note these rules carefully 1. Make your drawing of girl exactly 6 inches high, on paper 5 inches wide by 7 inches high. Draw only the girl, not the lettering. 2. Use only pencil or pen. 3. No drawings will be returned. 4. Write your name, address, age and occupation on the back of your drawing. 5. All drawings must be received in Minneapolis Lj April 10, 1929. Prizes will be awarded for ing best in pro- rtion and neatness by Faculty mem- Gare of the Federal Schools, Inc. All contestants will be notified of the prize winners. Make your drawing of the gi'l — -— send it to the address given in this ad. mmercial Designing Minneapolis, Minn.

Page 148

Make Big Money in a Radio Business of time installing, servicing, selling Radio sets. Not ‘ Jong ago I earned enough _ Don’t ever think that just working te ene wesk ‘to ‘pay for bard day after day. will bring you am ay course.” income big enough to enjoy all the goo things of life. You’ve probably found 4 2 on a ad out better already. Here is why some Haverhill. Mass. men easily make much more money than others. They have their eyes wide open all the time for signs of the great | derli ig success.

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The Real Fathers of Flight (Continued from page 157) for carfare,”’ mutters Orville on arrival at the home town. “Well, I can walk.” He lugged the weighty suitcases a mile and a half to the Hawthorn Street house, astonish- ing father and sister with his unheralded appearance. ** Well, I’m here,” he stated. It was a fact. About a week later, on December 9, Orville was boarding a train to return to Kitty Hawk with new shafts made of solid steel—something different from tubing and gas pipe, that would withstand the playful spite of whizzing pro- pellers. He bought a newspaper and read a dispatch from Washington, D. C., to the effect that the flying machine designed by Prof. S. P. Langley, Secretary of the Smithsonian In- stitution, had crashed in the Potomac River at the time of launching from a house boat. Over $70,000 of Government and other funds had been spent on the ill-fated attempt. OUBTLESS Orville felt a momentary chill as he read. On the heels of this monumental failure, he and his brother Wilbur were aiming to succeed. What chance had a pair of self-taught bicycle men, who had not spent one tenth of $70,000 in all their aerial research to prove the validity of dubious dreams? The Wrights’ diary tells that Orville arrived in camp on Friday, December 11, and that next day there was an abortive test of the machine on its starting track, a sixty-foot monorail of iron-shod wood. Sunday, as usual, was a day of rest. At 1:30 p.m. Monday, says the diary, a signal was set for the men of the Government life-saving station who were to lend a hand. Five men came and helped carry the machine up Kill Devil Hill and to lay track on a slope of eight degrees fifty minutes. The brothers tossed a coin for the first ride and Wilbur won. He climbed in and lay on his stomach. There was trouble with the re- leasing device. It was fixed up. Wilbur shot forward prematurely, Orville clinging to the right wing struts and running alongside as fast as he could go. At forty feet the younger brother had to quit and then snapped his stop watch. The machine had lifted a bit, six or eight feet from the end of the track. Now at a distance of some sixty feet from the track it was about fifteen feet above the ground. It lost headway and shortly came down on its left wing, breaking several pieces of the wooden frame, including one skid. The excited Wilbur forgot to stop his engine for some time after landing. The flight lasted three and one half seconds and covered one hundred and five feet. yy et. boys, the dingus flies,” we may imagine a sun-tanned brawny life-saver saying to his mates. ‘“‘Don’t know what use it is. Give me a boat or a buggy for travel.” Only that it might confuse the record and upset the agreed-on fable which is history, I refrain from the assertion that man made his first flight in an airplane on Monday, Dec. 14, 1903. Let us wait patiently for the official date three days later. Wilbur sent a short wire to his father report- ing the initial flight; misjudgment had reduced distance; success was certain. The brothers were rightly confident, for they had now proved the last doubtful point—ef- ficiency of propellers. This came up to the figured sixty-six percent, or a third more than Maxim or Langley had attained. Tuesday: was spent on repairs. These were completed by Wednesday noon and the ma- chine was set on its track in front of the camp for a try-out on the level. The wind was too light for an attempt. As the brothers awaited a proper breeze, a stranger wandered up from nowhere and said: ““What do you call (Continued on page 159)

APRIL, 1929 “OPPORTUNITIES In Traffic Management” P< age in Traffic Ne . book, should Mo sontey ual man seek. ing advancement in traffic work, This book points the way to the hi in the field of Traffic Manegeaaee ioe men once on small salaries have demonstrated their ability to make savings for the companies they work for and thus rise to more responsible Positions, The field of Traffic Management offers real opportunity only to the man who knows, Spare time study and the will to succeed have pushed scores of traffic employees up the ladder of financial succegs, LaSalle-trained traffic managers — both in thea road and industrial field—now command salaries of $5,000, $7,500 a year and better. Investigate! Send for this free book today. Find out how you cay qualify for these higher positions home-study training and guidance. Write now for your free copy of “‘Opportunities in Traffic ment.” Address— LASALLE EXTENSION UNIVERSITY Dept.483 T Chicago, Ill,

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29 MONEY MAKING OPPORTUNITIES SECTION 159 ApRIL, 192 acting —— The Real Fathers of Flight (Continued from page 158) aS , this thing—flying machine?” You get these Gen- aine High Quality, Imported Drawing Instraments, 14 my Home ART 3 Ba “y es, it is = ee — Wilbur (I These Two 2 Training = Dositiong Re ie you going to do with it?” Books— rated “We expect to fly in it when conditions are Mail Coupon! : a” . : Set had ‘Te faroeali, remarked the stranger after walking Yes, Absolutely etude sound the machine with eyes of keen ap- : of tral cla “T should think that thing might fly— nditions are favorable.” ar Re tieens of Kitty Hawk had been a iF Salaries of .'s 78 , ate! ‘formally invited by the Wrights to view a F ef You a oie next day, Whusnday, December 17. Money Back ae A few years later crowned heads and crowds Agreement ic Manage. of a quarter million folk thrilled over the same S siehicadte marvel, but the virgin voyage of the airplane geet sem Sieoae. — ERSITY drew only a couple of spectators. The natives t. Ifmy Back L. were hardly enough interested to be skeptical. sae satisfy in te Perhaps the brothers had a shrewd thought to insure privacy by asking everybody to come around. The abysmal ignorance of the natives seems laughable until we reflect that the wisest of scientists were then little better informed, regarding the air as a gas but not as a highway. you have finished, you get every penny back. of Education, whack T= inventors themselves, despite their Just Send the Coupon Below! Ne Bea Ms science and the success of their first D dtd dalek bop, had moments of pasting ee. J obs for Yr afitsmen Sid ten wiarl oon knew; yet o knows anything: ey ram i daeed say with a Makt aides. Now in Great Industries—Learn At Home | © bizh school graduate. } H . i i i , a we Bi who are making from $3,500.00 to $9,000.00 © Soe | [Mitalictitutticamnccen | | Statics mamma att: | Help As Long ter of Gan the thrust of a dozen wild horses. Men had p~ TF. RA : Gat started mow toward 8 betine position pad As ou Need t been killed by falling with gliders only house- Aviation is expanding t proporth Comfortable surrcandings.” Inside work. As my student you can TPHA high. A drop of a few feet with the power ey eer ay eee Earn As You Learn write to me any time you ay machine might finish rider and ruin hopes. —: ~~ geass plies ford techs attes beginning un Sane” * | want toand as often as you Ps Thursday. was sunless and wintry. A chill Define of stapes, homes, Mastebtes and office ss and I will give you Soe wind blew. Ice floes were visible along the agp th enteteh tte stems to get a job with: lp on any subject per- —— shore of Albemarle Sound and some whitecaps aren m Grattan.” No machinery can bo on thi berees Em, | taining to draftsmanship. ] on the Atlantic Ocean whose surf drummed I train goo st in Drafting. Keep the 5 hat I be Trained en I wil] advise you about by the beach half a mile away. The long strip of pee An eee sree - — Jl work themselves, in @ jobs, extra work, fees and white sand between ocean and sound was hy ty ee FS ‘ ‘trained by me. how to make extra money. With tted with ice-skimmed gray pools of water. 1 I leaden sky with drifting cloud-wrack har- if You Earn Less Than Pod daecitli) Geile fil,’ monized with the bleakness of the scene below. $70.00 a Week [SS a neeeeeeseeeeeeseeesesacees: anaes Sa Ask for My 2 FREE Books Mi... iia The man-made bird on the sand was no s skip alse plan to carn tongy while laraing and, prea of match in grace for its rivals overhead. It was Pell, this coupon, at once. Cet My Pay Raising big: money paying positions, your new much larger. Its cream-colored wings spanned — them point the way to Success. Youowe it to your- ° forty feet with an area of 510 square feet. Ee. Prevticelly oll indentries, for Draftemon. Thee 8 ons pan There was a twin vertical rudder behind and 3 > Mail the Coupon for them TODAY. . in front a twin horizontal rudder of forty-eight i. O die square feet, but a spectator could hardly tell “Pit grain you |) os OCINEER DOBE ° which end went first. The rider would lie on ee nate | a eee a ees ‘State his stomach between the main wings, flanked by engine and by whizzing propellers, using and twisting hips in a movable cradle to balance and guide the craft. Wiser WRIGHT was thirty-six and Orville thirty-two years old at this time. They were in their physical and mental prime. The height of the elder was five feet, ten and ° a quarter inches, that of the younger just one and three fourths inches less. Their weight was nearly equal at 145 pounds, which saved trouble in calculating total load for the ma- chine. Their oval faces were smooth shaven. Wilbur had a prominent aquiline nose, firm thin lips with incipient upward lines at the corners, a little baldness at the forehead. rville’s hair was yet thick and curly, brown I ont cat with a hint of red. Both had grayish-blue ee eyes, a _ and frank. ong voices k ' : cae oe ee were e, soft and quiet, similar in tone, nm mmm VALUABLE COUPONe ew se ome Wilbur’s more inclined to staccato. They were rd ITUTE swift in physical action, deft and nimble. RAILWAY POSTAL CLERKS oe ‘cae GT N.Y. Athletes of a delicate type, they felt the | MANY OTHER U. S. GOVERNMENT POSITIONS o Rae free of charge: 82-page book with let biting cold of that historic day and could not @ Set the job hero che withstand it like the heody sien. They had $1700 to $3300 a Year re Cities mop Travel for “‘Uncle Sam”’ : - Railway Postal Clerk . . . ($1900-$2700) to run indoors frequently to get warm over MEN - BOYS - 18 up of chert Oitice Clerk... - = 58798-52808) carbide can stove, filled with blazing Short Hours Rapid Advancement ¢ ..Rural Mall Carrier . 3. . — . ($2200- driftwood . They slapped arms, danced and | Steady Work Permanent Employment Pd . Prohibition Agent * + «+ « «+ £$2300-$3400) jumped in the nippy (Continued on page 160) Long Vacation With Pay o Name ccccencncncscccecccnccccccsesccncsccsssesesensecseccees Mail Coupon Today ActatOnce ¢ Address, a COE E EEE EERE EERE EEE EE EE EE EEE E TEES EOEA EERO ED

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I RE Ee oe “The Boss Was Stumped” “He was us, te Sanyo out 6 wa to speed machines. I could see he was genpet and es him if he would let me try my hand at it. “Go ahead,’ he said, ‘but I don’t believe you can help much. Looks like an outside job to me. “So I started t in and pretty soon I had the whole thing worked out. The was watching me and I could see he was surp ou learn a that? he am » that is. “And then I told h d been ts through the Trtanationl “ ‘How did quiet way of studying , Be home ni “He didn’t + say anything more and TI thought he had f ten all about it until LY called me in his office a few weeks later and said he was going to make me foreman increase my salary $75 a month.” That’s a true story of what spare-time study has done for just one man. There are thousands of others. Why don’t you take up a home-study course with the International Correspondence Schools and pore penn to earn more money? _—_——_—_— —_— * INTERNATIONAL CORRESPONDENCE : SCHOOLS “The Universal University’”’ Bex 7622-F, Scranton, Penna. Without cost or obligation on om By part pleese @ copy of your 48-page booklet, “* ho Wins and Why. ond tell me how I can qualify for the position, or in the subject, before which I have marked an X BUSINESS TRAINING COURSES usiness Management Business Correspondence Industrial Management [)Show Card and Sign ement Lettering ee Gtenography and Typing Civil Service Cost Accounting Railway Mail Clerk Book. Mail er Secretarial Work _JCommon School Subjects Spanish Freach High School Subjects Salesma Tilustrating [} Cartooning Advertising Lumber Dealer TECHNICAL AND INDUSTRIAL COURSES Automobile Work Airplane Engines Plumber and Steam Fitter Plumbing Inspector Foreman Plumber Heating and Ventilation Sheet-Metal Worker —— Engineer Engineer Refrigeration E Engineer Draftsman TOILILILILICI ane and Builder Draftsman rasa an cy Mining Engi Cotton Manufacturing Woolen Manufacturing Agriculture [] Fruit Growing Poultry me Mathematics Radio a Operating State. TURN YOUR TALENT INTO MONEY earn from $50 to $250 per week—some even more. Cartoonists Remarkable Circle System of Drawing teaches you in half the usual time. Students from all parts of the world are pe for this exceptional instruction. Persenal criticism service up-to-the-minute instruction make it easy for National students to attain success. Send for interesting BOOKLET and SAMPLE LESSON PLATE explaining full details of the Course and what National —- are ery one No salesman will call. The National heel ° f Cartooning, 615 Penten Building Cleveland, Ohio MONEY MAKING OPPORTUNITIES SECTION The Real Fathers of Flight (Continued from page 159) wind outside. After all, they had no sort of flying costume, not very warm ordinary clothes, and could not wear overcoats during the virgin flights. Five persons who came as aids or spectators witnessed the airplane debut. They were John T. Daniels, W. S. Dough, and A. D. Etheridge of the life-saving station; W. C. Brinkley, a lumber buyer of Manteo, and Johnny Moore of Nag’s Head, a sixteen-year-old who stumbled upon more wonder that day than the luckiest Boy Scout has ever chanced upon since. Johnny’s name will not perish. He was there! At 10:35 a.m. in a north wind of twenty- seven miles an hour, Orville boarded the roar- ing craft for the first ride, rose ten feet or so, scooted uncertainly up and down owing to a difficult control of the ill-balanced front rudder, and came to earth about a hundred feet from the track end. The time was about twelve seconds. This was, in truth, the first flight of aviations’ accepted birthday. AFTER minor repairs, Wilbur, at 11:20 o'clock, made a flight of about 175 feet. Orville had the third trip at 11:40 o’clock, reaching an altitude of about fourteen feet and about the same distance as his brother. The merit of the lateral control was happily shown when the left wing hit the ground first. At noon Wilbur embarked on the fourth and last flight. The craft jogged up and down for three or four hundred feet, then the pilot lev- eled it to a fairly even course. Smoke and flame belched from the open exhaust. Snarling propellers and bellowing cylinders drowned the shouts of the excited spectators. The pro- longed explosive tumult reverberated between sand dunes and leaden sky, alarming the loftily soaring eagles, warning them that their exclu- sive dominion was over and that winged man would soon chase and outstrip them as they now chased and caught lesser birds. On, on sped the airplane. It was 800 feet from the start when it came to a small hummock. Per- haps the ridge caused a down-gust or rut in the aerial highway. The craft wavered, began to pitch up and down as at the start, then quickly darted to the sand. Only the front rudder frame was damaged. | (THE flight was 852 feet in distance over the ground, and the time was fifty-nine seconds. A few minutes after the voyage the airplane, which had been placed alongside the camp shed, indulged itself in a festive somersault with the aid of the wind. It was partly smashed. You can see this very craft today in the Science Museum at London, where the King of England and many thousands of his subjects have been viewing it during the last year. Let us hope that with an end to an unseemly and senseless dispute, this precious American trophy will be brought to its proper home in the National Museum at Washington. A certain telegram belongs with the airplane. When his sons left home that year, Father Wright gave them a dollar with the remark: “* Now let’s hear from you when there is news.” The dollar was a good investment, it brought the following result: The Western Union Telegraph Company Via Norfolk Va., 176 C KA CS 83 Paid. Kitty Hawk N C Dec 17 Bishop M. Wright, 7 Hawthorne St. Success four flights thursday morning all against twenty one mile wind started from Level with engine power alone average speed through air thirty one miles longest 57 seconds inform Press home Christmas. 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OPPORTUNITIES SECTION THIS MAN iS MAKING MONEY M jpn, 1929 Y MAKING ae . -egest Engineering Job ol Ever Tackled

Grind it as you find it. Mower slips into sharpener without being dismantled.

(Continued from page 32) developed a great coal and cement War, he at ree han. This involved running property Mo the coast, building a harbor. And a inane? spreads as wide as the world, so a can touch only the high points. Let us finish with Australia. A few years after Hoover took service with the Chinese Emperor, he was back again, this time at Hill, Australia, where lay an immense rea of very low-grade zinc ore. Months and : of experiment with flotation processes, of see Sgaring on the separate branches of the enterprise, and Hoover had created for his 4 ders one of the largest and soundest mining properties in that corner of the world. Asia, where he first sank his teeth into a really big new job—where he had his early, romantic adventures with exploring new country and standing siege from the Boxers—called him back again and again. _When, in 1914, he dropped mining engineering for human engi- neering, he probably knew that continent bet- ter than any other except his own.

1S old associates best remember, for its H technical and human interest, his “lead job” in the Burmese jungle some thirty miles above Mandalay. This, like an even bigger job in Siberia which he laid down when the war broke, was geologically a twin to our own Leadville. Long ago, the Chinese had scooped out from this wild ground a wealth of silver- bearing lead carbonates. That ore is always an oxidization from deeper-lying bodies of more refractory ores. There may be only a thread remaining from the process of oxidization, or there may be a bonanza. Hoover and his men located the parent body in a certain hill. They had first to run a railroad through a most diffi- cult country. This job, and especially the item of bridging by ingenious means of their own a ingly unbridgeable chasm, brought epi- sodes of which they are telling stories yet. They got their American machinery assem- bled and ran a tunnel into the hill. But the d was “heavy”; timber would not hold. y took to masonry. The same problem when they ran into the great ore body. They solved this by an ingenious system of pillars and of filling in with material sent down shafts generated their own power and sanitated the district to make it habitable for a working force. Before they finished, they had dipped they had built up in the jungle a busy, healthy, main hand with the management of four great properties in the gigantic Russian Empire —a gold mining company under the Arctic Cirele in remote Siberia, a copper company in the Caucasus, another lead and silver proposi- tion on the Irkutsk River near the border be- tween Siberia and Turkestan, and finally a most complex business at Kyshtim on the Rus- sian side of the Ural Mountains. Here lay an enormous principality, rich in forests and in es of low-grade copper and iron. The lords of this land had been trying vainly for one hundred and fifty years to make it pay. The company for which Hoover was executive took over the development of all these resources col- ively. By most expert technical work, by saving and utilizing a score of by-products, by rdinating everything, it put the estate on a basis of low but steady dividends. ; job, coming late in his private career, is important not only as illustrating how Hoover's * ‘ grew from simplicity to complexity, but Wit was flowing (Continued on page 162)

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fromabove. By similarly original devices, they | into almost every branch of engineering. And | and prosperous community of twenty-five thousand. BESIDES minor enterprises, Hoover ha: a |

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Page 152

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ET the ces cc ee oe aeare a. 0k oe le ae a EE Dr eet adc sci deneunes buccaneers Tee ee Boonen aatnsess . e 3 4 here if interested only in one for your own home. MONEY MAKING OPPORTUNITIES SECTION The Biggest Engineering Job Hoover Ever Tackled (Continued from page 161) over into the field of human engineering. The work required expert technical personnel. And Hoover’s company, managing somehow to evade the Czarist prejudice against educating the masses, put virtually all the population to school. Some day, as they developed and trained executives and technicians, they hoped to withdraw their Americans, leaving the job entirely to the Russians. When the war broke, this enterprise supported, in a comfort and enlightenment they had never known before, some 175,000 people. It carried on through the Czarist stage of the war; but Bolshevism par- alyzed it. Kyshtim, in 1922, was one of the famine districts which Hoover’s men relieved. So much, in a few strokes, for Asia. To finish his roster of continents, he worked on the northern and southern tips of Africa—jewel mines in the Sinai peninsula, gold in South Africa. In Western Europe he had relations with reduction works in Belgium and Germany, and accepted the interesting job of running down for the Italian government the Roman iron mines of the Alps. And from his home office in San Francisco, he worked on our conti- nent with Southern California borax deposits, oil-pipe lines, and British Columbian gold mines. (‘THE world knows his big jobs since 1914. I merely repeat that the constantly expanding operations of mercy, by which he directed the feeding of two hundred millions of people, had the engineering cast, as well as that human touch which never fails in Hoover’s work. Finally, the job with the Department of Com- merce illustrated, for perhaps the first time in human history, how high engineering practice, without conflicting with democratic institu- tions, might be applied to the whole business of government. By pure coincidence, he comes into his ad- ministration at a time when our Government has facing it more straight and obvious engi- neering jobs than ever before in its history. There is the enormous task of revising the flood protection of the Mississippi River. There is the sound but extensive plan, which Hoover has been boosting in the Department of Com- merce, for internal waterways. There is the problem of a deep-sea outlet from the Great Lakes to the Atlantic. Finally, we are ap- proaching the point when the Panama Canal can no longer handle the traffic. We must either parallel it with another ditch or dig a new canal-—probably across Nicaragua. yt his administration may put all these jobs soundly on foot, and still leave behind it another memory which will last longer in history. He brings to the White House, as he did to the Department of Commerce, the dawn of a new conception in government. The pat- tern of our industries is shot with black streaks which represent enormous waste—nobody’s fault, just a flaw of growth. The same thing holds, probably, for the pattern of our Govern- ment. What we may yet call political engineer- ing tries to eliminate those spots by coérdinat- ing the whole structure. The method, as already practiced by Hoover in the Depart- ment of Commerce, does not recognize compul- sion as a tool. It tries to accomplish its ends with as little legislation as possible. It con- ceives of government as an onlooker who from a high position can view the whole field, see the flaws invisible to dwellers in the valleys, and accomplish correction by enlightenment and persuasion. That conception of engineering method as applied to government may be Hoover's supreme contribution not only to his own nation but to human history. Aprn, } START TO PLAY VERY FIRST pjy 2 ; a ) 6 >) Minutes after I unparteds Xylorimba J started playin No teacher: Phoe pntpnuten reer pon are 208, Bae the sae playing *‘Old Black Joe’’ Cv aaa Sons take you, step by step, an ant qad 5 Pres Sok Galore: ¢:_Soon zon ire: wi become e center, ‘ot interest make $5 to 0 $25 a 7h that is ever radio or on Saws. seen The Musical Hal regularly earn we ES his — > sa Chicago. played 5 oem minutes. at at Seed seas, BIG BOOK F REE f= “Tgtereting, well ilustrated gine fun sapere of of playing th the is Parken year to fo obi fine arta hele Botkin tavaven J.C. 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MONEY MAKING OPPORTUNITIES SECTION At the right is a view of my draft- ing and specification offices where a large staff of experienced expertsare in my constant employ. All drawings and spec- ifications are pre- pared under my per- sonal supervision, Patent Law My Offices ~ Just Across Street From Protect Your Ideas Take the First Step Today—Action Counts nventors ff you have a useful, practical, novel idea for any new article or for an improvement on an old one, you should communicate with a competent ‘ Registered Patent Attorney AT ONCE. Every year thousands of applica- tions for patents are filed in the U. S. Patent Office. Frequently two or more applications are made for the same or substantially the same idea (even though the inventors may live in different sections of the country and be entirely unknown to one another). In such a case, the burden of proof rests upon the last application filed. Delays of even a few days in filing the application sometimes mean the loss of a patent. So lose no — time, Get in touch with me at once by mailing the coupon below. Prompt, Careful, Efficient Service This large, experienced organization devotes its entire time and attention to patent and trademark cases. Our offices are directly across the street from the U. S. Patent Office. We understand the technicalities of patent law. We know the rules and requirements of the Patent Office. We can eerwrd in the quickest, safest and best ways in preparing an application a patent covering your idea. Our success has been built on the strength of careful, efficient, satisfactory service to inventors and trade- mark owners located in every state in the Union. Strict Secrecy Preserved— Write Me in Confidence All communications, sketches, drawings, etc., are held in strictest confidence in strong, steel, fireproof files, which are accessible only to authorized members of my staff. Feel free to write me fully and frankly. Itis probable that I can help you. Highest references. But FIRST—clip the coupon and get my free book. Do THAT rizht Row. No Charge for Information On How to Proceed The booklet shown here contains valuable information relating to patent procedure that every inventor should have. And with it I will send you my Record of Invention” form, on which you can sketch your idea and neh its date before a witness. Such evidence may later prove valu- _ you. Simply mail the coupon and I will send you the booklet, and Record of Invention” form, together with detailed information on how to Proceed and the costs involved. Do this NOW. No need to lose a minute’s time. The coupon will bring you complete information entirely t charge or obligation. Clarence A. O’Brien Registered Patent Attorney Member of Bar of: Supreme Court of the United States: Court of Aspeate, District of Columbia; Supreme aan District of Columbia; United States Court of Claims, CLARENCE A. O’BRIEN Registered Patent Attorney 88-F Security Savings and Commercial Bank Bldg., Washington, D. C. =_—" = Suite 1106 Woolworth Bldg., New York City. Please send me your free book, ‘‘How to Obtain a Patent,” and your “Record of Invention’’ form without any cost or obligation on my part. PRACTICE CONFINED EXCLUSIVELY TO PATENTS, TRADEMARKS AND COPYRIGHTS (Important: Write Plainly and Address Office Nearest You)

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MONEY MAKING OPPORTUNITIES SECTION ‘Last night I came home with great news” “T’> TELEPHONED Ruth thet I had a surprise for her and she could hardly wait for me to get home. You should have seen her face when I told her the Boss had called me in and given me a $25 increase in salary. “ Tt’s wonderful,’ she said, ‘just wonderful. Now we can pay some of those bills that have been worrying us and even put a little in the bank each week. “ ‘Remember the night we saw that coupon in a magazine and you decided to take up an I. C. S. course? It made a new man of you, Bob, and I knew it wouldn’t be long before the firm would notice the difference in your work. “ ‘We certainly owe a lot to the International Correspondence Schools. You would never have received this increase if you hadn’t studied at home and prepared yourself for bigger work.’ ” How about you? Are you always going to work for a small salary? Are you going to waste your natural ability all your life? Or are you going to get ahead in a big way? It all depends on what you do with your spare time. Don’t let another precious hour pass before you find 4 — the I. C. S. can for you. It doesn’t cost cularay b or obligate you in any way to ask for full particule but that one simple, little act may be the changing your entire life. Do it now! Mail Coupon for F Free } Booklet INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7623-F, Scranton, Penna. thout cost or obligation, please send me a copy of your booklet, “Who Wins and Why,’’ and full particulars about the subject before which I have marked X: BUSINESS TRAINING COURSES Business Management oe means of Industrial Management English Personnel Management Business Correspondence Show Card and Sign Lettering Stenography and Typing Civil Service Railway Mail Clerk Common School Subjects Secretarial_Work High School Subjects Spanish [ French Illustrating (J Cartooning TECHNICAL AND INDUSTRIAL COURSES Electrical Engineer Architect Electric Lighti Traffic Management Accounting and C. P. A, - Salesmanship Architects’ Blueprints Mechanical Engineer Contractor and Builder Mechanical Draftsman Architectural Draftsman Machine Shop Practice Conerete Builder Railroad Positions Structural Engineer Gas Engine Operating Chemistry Pharmacy Civil Engineer () Mining Automobile Work Surveying and Mapping Airplane Engines Plumbing and Heatin; Agriculture and Poultry Steam Engineering Mathematics Street Address. City Occupation If you reside in Canada, send this coupon to the Interna- tional Correspondence Schools Canadian, Limited, Montreal Send details of your inven- tion or patent at once, or write for information. In business 30 years. Com- Es facilities. References. Adam Fisher Mfg. Co., 183-D Enright, St. Louis, Mo. ‘On 10) NY 103 OME a auring ence nothing eles like it. in Modern >ol pare time. ‘also earn while y learn. spare you Cannonball Baker, Automo- bile ‘‘Broncho Buster’’ (Continued from page 51) hour, stopping only for gas and oil (and water for myself). That track was as hot asa griddle; there wasn’t a breath of wind to ease the rays of a midsummer sun. About eleven pP.M., when I was well in the lead, and everything seemed to be rolling my way, a swarm of gnats settled over the track. The tiny insects began splattering against my goggles; they'd stick there, and as soon as I'd wipe them off, another batch would come at my glasses like water out of a hose. Finally, one of them shot past the corner of my goggles, and landed smack in the corner of my eye! A harpoon couldn’t have hurt worse. The pain drove me frantic, and before I knew what had happened, my machine was headed for the top of the bowl-shaped track. In another yard it would have crashed through the guardrail and prob- ably have killed half a dozen spectators. I jerked the front wheel ‘hard about’, as sailors say, but the movement was too abrupt. I was hurtled through the air, my bike tore ahead like a crazy rocket—and when I regained con- sciousness I was in the accident ward, with one eye blinder than a mole. The gnat had been removed, but the doctor told me it had paralyzed an optic nerve, and that only careful treatment would bring the eye back to normal. ELL, as I lay there all banged up, I started figuring how I could get back into that race. I reckoned that if I could aver- age seventy an hourtill morning, I'd still have a chance at the prize. So I turned to the medico and asked him if my machine had been injured much. “Why no,” he said. “It’s in the pit, and in better condition than you are right now.” That was enough for me. “Doc,” I said, ‘I'll be back for breakfast.’’ Then I bounced off my cot and started for the track, steering with one good eye. The medico thought I was crazy, but I was never saner in my life. I wanted that first-prize money, and I wanted the satisfaction of knowing that I could take a fall and still keep going! During the next seven hours I whirled around that track like a marble in a cup, and when eight a.m. arrived I had hung up a new track record of 1,534 miles. With both eyes open I’d have done 200 miles better than that. After I had made certain I could take a long- distance licking, I conceived the idea that I could be of service to automobile manufactur- ers who wanted to give their product the severest possible testing under actual road conditions. A thousand miles of road test is worth ten thousand miles of laboratory analysis. So I broached my proposition to R. E. Olds, designer of the Reo and the Olds- mobile, and one of the great geniuses in the automotive industry. HAT is the hardest test you can think of?” he asked, after we had talked over my plan. ** A transcontinental run,”’ I replied. “‘ Among other obstacles lying between the two oceans are a couple of mountain ranges, a sizzling desert, and about 2,000 miles of terrible roads.”’ “What's the existing record, Cannonball?” ‘Eleven days and seven hours.” Then I added, “‘ And I think I can clipa day ortwo off that.” Mr. Olds promised me a bonus for every twenty-four hours I could clip off the old record. Until this time the transcontinental drive had been regarded as a two-man job; one man driving while the other slept. But I figured that I could make better time alone. Col. Lindbergh has the right idea about this “Lone Eagle” business, too. You go farther and faster when you travel solo. I started from Los Angeles on May 16, 1916, and my tough luck (Continued on page 166) Make Your Vest Pocker ‘ar: = ARRY this amazing new: adding machine in your vest | §j 4 Be pocket. Make $3.00 an hour showing it to storekeepers, bookk others. Agents cleaning up with tis fast caleeeianal does any kind of figuring needs it and will bay on sight, Complete Adding Machine —a tT VE-PO-AD duplicates Wo large adding “on vend Yoa don’t need $175 his first week. Others a ba od > ig You can Dept, 154, Chi “Advertisin: 2nd your address for f0d zpct name and vii tal facts about ne free hock ind out, ‘ou at home, in time, for >porti nities op cal work, shed school. 8 Succosefol eradaa Sraqueten Riera = PAGE - DAVIS SCHOOL OF At Dept. 1364, 3601 Michigan Ave., Chicago, “STAMMER lfs Guuse and Gire* You can be quickly cured if ~ By 5 cents, coin or stamps, for 2. e cloth bound on Stammering and deut carina ae tells how I myself after Gsqmmering — Stuttering ora E BENJ N 11864 Bogue Bidg., 1147 N. 111. St. In 173 W. Madison St., Learn Cartooning At Home—in Your Spare Time The famous Picture ChartMethod of teaching original drawing has opened the door of success for hun- dreds of beginners. Whether you think you have talent or not, send for sa — chart to test your abil- ity, and examples of the —— of students earning from lh de 300 per week. Please state you THELANDON SCHOOL 1451 National Bidg., Cleveland, 0. AccounTm Executive Agepantante ond Thousands of firm = Foaby $,000 ants in the United States. We train you Chorot at for CP. A. or accounting conan | ex, lence unnecessary. Trai: Whtiam B. Castenholz, A. me oe — a large caf of | A.’s, including members of the American Institute of Write for free book, ccountancy, the Profeasion that LaSalle le Extension. Univers 483-H World's Largest Business Training tnstiiien — HS PAINT , SPRAY DOES THE WORKOF FIVE, MEN % Facey Saaiete, Saaz, month whe ogee iar Bo re 3O DAYS TRIAL ae >t ' QUICKLY PAYS ox 7 | FOR ITSELF. 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Cannonball Baker, Auto- mobile ‘“‘Broncho Buster’’ (Continued from page 164) commenced almost immediately. Crossing the Mojave Desert with the sun baking everything at 120 degrees, I had to change tires five times in eighty miles. On the second day out, my oil pipe shook loose, became detached, and I lost all my oil. Between Arizona and Missouri, everything rolled along fine; but the black mud in Missouri and Kansas nearly ruined my chances. A cloudburst transformed the soft roads to quagmires, and things got so bad that I covered only ten miles in two hours. Once I came to a place where a dozen autos jammed the road ahead of me. Teams of horses were dragging them out one by one, and I figured I'd be held up for ten hours anyway. In des- peration I hit upon the plan of pulling around the jammed cars by cutting out of line and ploughing through a hayfield. In mud up to my hub caps, I churned around for a bad half hour, but finally pulled out onto the road, ahead of the bogged automobiles. Still, even through the mud, I beat a letter posted in Emporia, Kansas, to New York City. You can bet I traveled during that last 1,500 miles! I did it in two days, and reached New York City just seven days, eleven hours, and fifty- two minutes after I had started. I had cov- ered a distance of 3,471 miles—and had slept only seven hours while doing it! SPE: AKING of sleep, I find that a little goes a long way with me. But when I do get drowsy, I never allow myself to doze at the wheel. That’s the one sure way to catastrophe. I just pull up into the side of the road, take a catnap for half an hour, and then awake much refreshed for my next hop. After my trans- continental trips, I usually sleep about eight hours and then feel fine. When not actually racing, I train like an athlete, and although I’m forty-five years old I seem to be getting better all the time. I knew I could better my own coast-to- coast record censiderably, and began at once to make plans to do so. But in the meantime I took some short trips, just to keep in trim. I drove a stock Rickenbacker over the Alle- ghenies in midwinter—from Indianapolis to New York—a distance of 778 miles in twenty- two hours. That was the coldest ride I ever took. After this, I took a flyer at Hawaii, which, they told me, had the toughest ninety-mile motorcycle course in the world. Well, that course was tough and no mistake. It circled the island of Oahu, a volcanic mountain with a thousand peaks. The road took in every one of these peaks, and at times would drop down sheer cliffs, just like a waterfall. 1 circled the island both ways, going*from right to left, and then counter-clockwise, just to show I could do it with either hand. My best time was made in the clockwise direction. I covered that ninety-mile course in two hours and four minutes—and half the time I wasn’t on the road at all. Four other chaps who have since tried to better my record have landed in the hospital; a fifth, I understand, bounced right off a mountain peak into the ocean. | pecrpe Hawaii I took a jaunt to Australia and annexed six consecutive records on one 500-mile road race. That was the greatest number of records I ever broke in twenty-four hours, although I regard the day as lost when I haven’t smashed at least one or two previous marks. Other fellows come along and break my records, and then I have to turn around and shatter theirs. It’s getting harder to im- prove the other fellow’s performance these days, but there’s still one or two worth while marks left to shoot at. The greatest of these is of course the coast-

to-coast record. I hold that now with my latest | performance in a (Continued on page 167)

PATENTS TRADE-MARKS SERVICE Without charge or obligation, we inform you on any questions you ma: to us touching on patent, trade-mar copyright law. You may ask: “Should | protect myself by patent, or register und the trade-mark or copyright laws? What | kind of a patent should I obtain?” and many other questions that may occur to ff you. These are vital points to consider and questions will be cheerfully answered, | Don't Lose Your Rights | To Patent Protection Before ‘wn your invention ti ' one send or. blank form “EVIDENCE OF CONCEPTION" to be signed and wit. nessed. As registered patent atto; we represent hundreds of inventors all # over the United States and Canada in the advancement of inventions. form “Evidence of Conception,” sample, instrue- tions relating to obtaining of _— and schedule of fees sent upon reques LANCASTER & ALLWINE 274 Ouray Building Washington, D. C.

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MONEY MAKING OPPORTUNITIES SECTION Apnit, 1929 pile “Broncho Buster’”’ (Continued from page 166) But it took me thirteen years to it. After I established my seven-day in 1916, Jack Mulford came along and clipped twelve hours off of it. Then I turned around and in 1920 drove a car under the aus- - oc of the U. S. Army Recruiting Service from Prashington to Los Angeles in five days and ty-two hours. This record stood unshat- for three years until a private citizen ghisked a Studebaker over the same route in five days and thirteen hours. This made me y TOSS. It was all right for a professional ig Ralph de Palma or Jack Mulford to take me for a fall, but to be licked by an amateur h! So I determined to beat the too muc . : are record—not in a passenger car, but in ! ae up a two-ton GMC with Atlantic sea water, and exactly four days and twenty- three hours later dumped that sea water into the Pacific Ocean. That happened in 1925, and my record stood unchallenged till I recently hurled a Knight across 3,453 miles in exactly seventy-three hours. That beats the railroad running time for the same route, and definitely proves that the modern automobile can stand the racking strain of a forced pace over all kinds of roads. URING my last trip, I didn’t raise the hood D once; nor did I make a single tire change. Ten ago it was enough to prove that an auto could make the distance. Now it’s neces- sary to demonstrate that it can make the dis- tance without a single repair. What’s the longest journey I ever made? Oh, a little tour that I call my “All-Capital Run,” in which I touched the capitals of forty- eight states and covered 16,234 miles in eighty days. I'd duck into a state capital, roll up to the Governor’s mansion to shake hands with the chief executive, and say a word or two in favor of good roads. Naturally I’m a booster onball Baker, Automo- | | ScrENTIFIC AMERICAN BUILDING 24 W. 40th St., New York City Tower BuILDING Chicago, ‘Ill. Van Nuys Buitp1Inc Los Angeles, Cal. Cr&GOEIAD Books and Information on Patents and Trade-Marks by Request PATENTS TRADE-MARKS , FOREIGN PATENTS MUNN @ CO. PATENT ATTORNEYS Associated since 1846 with the Scientific American DESIGNS SCIENTIFIC AMERICAN BuILDING Washington, D. C. Hosart BuitpInG San Francisco, Cal. Associates in all Foreign Countries I’'LL PAY YOU A RAILWAY for better roadways. I believe that eventually the Atlantic and Pacific coast will be linked by one national highway, broad enough for four To Show This Sensational Pocket Lighter Value to Men! ents, here is the greatest Value and most sensational f Oe eS RAFFIC INSPECTOR EARN UP TO} cars abreast. When that day comes, and it’s pretty near at hand right now, we'll be crossing the continent in less than forty-eight hours. ee watch out! record I’m proudest of is my latest non- mark between Los Angeles and New York back again, a distance of 6,692 miles. In covered-wagon days it would have taken eight- een months to make that jaunt, but I did it in & Franklin in less than a week. My elapsed time for the round trip was 157 hours and twenty-three minutes, or just about 614 days. Yes, [had a companion on that trip to spell me when I needed a wink of sleep. But during that whole week I slept exactly nine hours. And what do you suppose I ate? Nothing but salted peanuts! I find that they are the greatest ener- gizers, and the handiest thing a man can eat twenty pounds of them while setting my great- est transcontinental record. EY W look at a map, you'll see that I trav- ‘éled in an air line between the two coastal cities. I wanted to beat my own previous time and the combined running times of The Chicf and the 20th Century Limited, the two fastest trains in the world. To do this, I couldn't afford to deviate from the crow-flight course, nomatter where it led me. From Los Angeles I shot straight across the sandy plateau of Ari- toma into Albuquerque, New Mexico; from I drew a bead on Dodge City, Iowa—a run of 600 miles. Three hailstorms nearly pelted me off the road, and 100 miles of gumbo mud pretty nearly broke my heart. I had to run thirty-five miles in low gear through the heavi- est of the mud—but by some mile-a-minute driving between (Continued on page 168) 2 elt during a gruelling strain. I consumed nearly . money maker you ever came across.The popular one hand Master Pocket Lighter—reg- ular $5.00 value—now sells cover wi shield — fine od y extra . d for 10 years. $5.00 Value — Sells for Only $1.50—You Make Over 130% Profit Dealers and consumers verywhere buy on a. Wil jams sold 48 in one day. 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Cotton Manufacturing Woolen Manufacturing Agriculture (] Fruit Growing Poultry Farmin Mathematics Radio 5% CHICA FOUNDED 4Fields of real opportu- nity. Big pay—a permanent position or a business of your own. 7 . cog dollars spent last year in one of these fields alone. Train here in Chicano, America’s in- dustrial center. par. diploma and 3-yr. B.S. Courses. - enue * practical que in Drafting. . Earn while you bern, Ba Enter any time. and even classes. No time wasted ae. terms. Athletics. Su Socpese = sverranere Free Free Be page, ues “*Blue Book MONEY MAKING OPPORTUNITIES SECTION APRIL, 199 Cannonball Baker, Auto- mobile ‘‘Broncho Buster’’ (Continued from page 167) Kansas City and St. Louis, I managed to land in the latter city some five hours ahead of my own record. In crossing the Alleghenies I lost this five-hour lead, in a cold fog that made every turn a lurking menace. But the worst was yet to come. When I hit Philly, I got tangled up in the maze of early evening traffic and as I progressed through the numerous New Jersey towns that dot the road between New York and Philadelphia, the density of traffic forced me to limp along at twenty-five miles an hour. I like to travel fast—but I'd rather be chief engineer of a brick scow than hit a single pedestrian or smash into a family car out for an evening spin. By respecting the New Jersey speed laws, I missed the Tottenville ferry (just outside of New York City), and my chance for a new transcontinental record went glimmering. You can bet I was disappointed when I reached New York City in seventy-four hours, an hour behind my own previous time. But I determined to turn right around, streak back over the same route, and make a new record for a two-way passage. Luck was with me this time; heading west, records fell like ninepins; and I rolled into Los Angeles exactly ten hours ahead of the old mark. I had beaten the best trains in the world by a full day, had consumed 527 gallons of gas, twenty-three quarts of oil, and 250,000 salted peanuts! That last figure is one that will never be beaten. [ve talked a lot about my long rides, but so far haven’t said anything about my short ones. In other words, my mountain-climbing trips, which usually aren’t more than ten miles from base to summit. Probably the most dangerous and often attempted climb is that of Mt. Washington in New Hampshire. I regard this climb as the single most treacherous stretch of road in the world, Pike’s Peak not excepted. Many drivers, amateur and profes- sional, have been killed in the attempt to scale Mt. Washington in an automobile, Jack Grant being the last and most famous driver to lose his life on that final forty-three-percent grade. Up until September 30, 1928, the record was held by my old friend Jack Mulford, who had covered the distance of seven and eight tenths miles in seventeen minutes flat. On the morn- ing of September 30, the betting was heavily against me to better Mulford’s record. The fact that the Tip-Top House at the peak of Mt. Washington was three miles above the clouds, and could be reached only by traveling up a curving, precipitous incline, made Mulford’s time seem almost unbeatable to those who were unfamiliar with my technique. Most drivers have to see the road ahead of them for at least ten yards, but if I can see the radiator cap, I can usually manage to pick my way. But on the morning of my ascent, the fog was so dense that I could barely see the front end of my Franklin Special! I started off from the Toll House at the foot of Mt. Washington, slipped my car into high gear, and made a mental resolution not to take it out of high at any point during the climb. NEARLY broke that resolution! For as I reached the level of the clouds, I saw that they were inky black; thick as wool, and just about as impervious to light. My head- lights were of no service at all, and there I was streaking up the side of a mountain, whirling around “S”’ curves, and hanging over yawning chasms, at fifty an hour! After ten minutes of climbing I knew I must be near the top; still I could not see a foot ahead of me. The road suddenly seemed to go straight up ahead of me, the onward rush of the car abated, and reluctantly I was reaching for my gear shift, when I almost ran into a chap waving a big red blanket. (Continued on page 169) ———__ In the Grand Central Zone Hotel Montclair Lexington Avenue 49th to 50th Sts, NEW YORK CITY Just Completed and Opened! 800 Rooms 800 Baths Each With Tub and Shower Radio in Every Room Room & Bath $3—$5 per day For 2 Persons $4 — $6 per day S. Gregory Taylor, President Oscar W. 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PRIL, 19% co ned! saths ver ApRIL 1929 MONEY MAKING OPPORTUNITIES SECTION Cannonball Baker, Auto- mobile ‘“‘Broncho Buster”’ (Continued from page 168) “Hey, Baker . - - Stop” he cried. “You're " You've reached the top! | jumped out of my car and shouted: “Did [break the record?” . “You certainly did, Cannonball. Your time is fourteen minutes forty-nine and three fifths seconds. ; snned happily as I turned the car down- si“ Want a ride down?”’ I shouted at the jal timer. ; oe. dechned with thanks. But he needn't have, because I didn’t break any records going down that hill. Flyers Open the World’s Ice Box (Continued from page 25) Contrasted with the Arctic, there is little fog in the region of the southern pole. The air above the ice is almost vaporless. The light is often a blinding glare that hides the contours of the ground and makes it difficult to see the hummocks and depressions in the ice. The North Pole is practically at sea level, in the midst of a frozen sea. The South Pole is located on solid land nearly 10,000 feet above sea level. To reach it, aerial explorers have to fly at the efficiency-reducing altitude of 12,000 feet to clear the mountains that bar the way. The depth of the ice mantling the plateaus and mountains of the frozen continent can only be guessed. A sensitive, 150-pound instrument may provide definite knowledge. It is similar to the sonic depth finders used on ships to determine the depth of water by recording the time required for an echo of a sound to return from sea bottom. This instrument will make “soundings” at different points on the ice se to discover the character of the land W. ANY mysteries are locked under this ice. For instance, there is evidence that what is now the world’s coldest spot was once partly tropical and contained flourishing forests. Per- haps there once lay across the Antarctic a “continental bridge’’ by which animals and plants traveled between Africa and South America in an early geologic period. The man who can lift the ice cap and peer beneath may pia — and cong maak gs = reveal e continent played in the past. Fi expeditions can transport scientists of the party by air to exposed spots, if any are discovered, so they can make a detailed study of the rocks. There are other questions to be answered. Does a mountain range reach toward the Pole from Graham Land, and is it a continuation of the Andean Cordilleras, which form “the backbone of South America”? Is the Ant- aretic continent, as some geographers believe, really two islands instead of a single con- ‘tinent, with the split connecting Ross Sea and Weddell Sea? There is also the possibility that im some sheltered valley the warmth may be ent for strange forms of life to exist. pomewhere,” Commander Byrd has said, im those tremendous areas, there must be lowlands where temperatures rise sufficiently to permit vegetable and animal life.... In some Antarctic valley, perhaps shut in by towering mountains, a thrilling discovery may await us,” IN THIS latest attack in what Shackleton called “the White Warfare of the South,” the world is sharing the thrill of discovery with explorers. Radio, playing a stellar réle, is carrying to all parts of the world a running story of events as they happen. en I Was Afraid of This New: Way to Learn Music — Until I Found It Was Easy As A-B-C 7 ON’T be silly, Mary. You're perfectly foolish D to believe you can learn to play the piano b that method. You are silly to even think about it.” That is how my husband felt when I showed him an ad telling about a new way to learn music. But how I hated to give up my new hope of learning to play the piano. Music had always been for me one of those dreams that never-come-true. Others could entertain their friends. But I was a mere listener. ‘or a week I resisted the temptation to look at the ad again, but finally, half-frightened, I wrote to the U. S. School of Music—without letting Jack know. Imagine my joy when the lessons started and I found they were easy as A. B A mere child could master them. I quickly saw how to blend notes into beauti- ful melodies. My progress was so rapid that soon I was rendering popular and classic selec- tions. For thru this short-cut method, all the difficult, tiresome parts of music have been eliminated. gr I decided to play for Jack. He was astonished. until it was revealed to them by our ‘‘Musical Ability Test.’ You, too, can learn to play your favorite instrue ment by note thru this short-cut method. }Send now Steady Work. hy... 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A quick consultation be. tween director and sound man, the Script of the play before them. “Ah, that’s it,” said the director § “That tornado was Walter (the actor playing the hero’s réle) tearing off his little corner newspaper!”’ Another quick conference. What to do? Tearing the paper is essential to the action; jt can’t be cut out. The director had an idea, “Moisten the corner of that newspaper and see what'll happen.” This was done. “Silence!’’ Three bells! Oy with the play! HE scene was retaken. In another play back the paper-tearing was inaudible. The cost of this little mishap, the sound man explained to me, was about $500. And this shows how valuable the play back really is. Had the scene been filmed directly the horrible noise would have remained unde. tected until after the developing process and the tearing of the inch-and-a-half bit of news- paper might have meant a loss of $10,000! This, I found out, was but one instance of the difficulties encountered in the “talkie” studio in reproducing ordinary noises of everyday life needed in the action of the pic ture. The firing of a gun or the barking of a dog will not record truly. The technician whose task it is to create “‘realistic” sounds, I learned, was called the “effects man.’ It is his job to produce the ingenious devices that make sounds seem natural in the finished “talkie.” The simplest odds and ends, such as tin cans, bits of string, old bottles, and the like are used in making these sound-imitating devices. An actor’s stage experience is of little help to him in the “talkies.’’ Instead of using the full voice, as on the stage, you have to in low, distinct conversational tones or the play back will make you sound like a hawker at a country fair. Incidentally, it is a weird sensa- tion to hear yourself talk in soundproof sur roundings. Because all echoes and reverbera- tions have vanished, your voice sounds lifeless; your words seem to die almost as they leave your lips. Another difference is that you may not walk about while delivering your lines. Instead, you must make all movements action calls for, then stop within range of a “‘mike” to voice your speeches. HE tiniest details have to be watched and listened for. For example, one of the office scenes had to be repeated many times before it was discovered that one of the actors, while talking, stood too close to a desk which, despite its felt padding, threw back his voice and created an echo in the play back. And as for coughing and sneezing—they are unpat- donable sins in a “‘talkie’’ studio! Yet, despite all vigilance and infinite pre cautions, it often requires an entire working day to take one little scene which will run from three to five minutes on the screen. I hadn’t been at the studio long before, one noon hour, I prevailed upon the sound expert to explain how the film or sound-track process works. The kernel of the matter is photographing variations in light intensity on a film. The sounds—the (Continued on page 171)

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Sh!—They’ re Filming **Talkies!’’ (Continued from page 170) actors’ voices, instrumental music, or what you will—are picked up by the “‘mikes”’ on the stage, which change sound vibrations into elec- trical vibrations. These are carried by wire to the sound department, where they are amplified. The amplified “speech current”’ actuates an electromechanical light valve in the sound- recording machine between a ribbon-filament projection lamp of constant intensity and a rapidly moving film. The alternations in the speech current cause the valve to open and close like a camera shutter: The original sound vibrations thus are translated into corresponding variations of light and recorded on the film. This record is in the form of a band of narrow cross lines of varying shades between clear white and black. The sound ribbon, as it is called, is later printed on the finished moving picture film. Sound and vision synchronization during the final “‘shooting” of the “talkie” is effected through a distributor which provides an exactly equal flow of current to the motors that grind the cameras on the stage and those that drive the sound-recording machines in the sound room. They move together, keeping step like soldiers. Now, when the “‘talkie’’ film is shown at your theater, what really happens is a reversal of the process that took place when it was made. The film, containing both picture and sound in a photographic record, is run through an ordinary motion picture projection machine to which has been attached a sound-reproduc- ing unit. This unit includes a light that is reflected upon the sound record of the film. As the sound record passes across this light, it interrupts the constant glare shining through it, causing variations of light and shadow to fall on a photo-electric cell, which has the property of changing these variations back into corresponding electrical vibrations. The latter are amplified and carried by wire from the projection booth to reproducing horns placed behind the screen and the horns trans- late them into sound. Result: you hear your favorite movie stars speak their lines! Two Important Flights 7 great flights by two famous pilots were recent events of important significance to the future development of aviation. One was the 2,000-mile trip of Col. Charles A. Lindbergh in piloting the first air mail from Miami, Fla., to Colon, Panama Canal Zone. The other was the record-breaking nonstop flight of Capt. Frank Hawkes across the con- tinent from Los Angeles, Calif., to Roosevelt Field, N. Y. Lindbergh’s journey, following a time sched- ule with his usual precision, marks a definite step in the fulfilment of plans for linking the countries of the Western Hemisphere in a net- work of air lines—plans which a year ago seemed almost visionary. It opened a new commercial service to the Canal Zone, with stops on the way. Eventually it is planned to extend the system from Panama southward along the east and west coasts of South America. Captain Hawkes, veteran air mail and racing pilot, drove his Lockheed-Vega monoplane through storms across the country in eighteen hours, twenty-one minutes, and fifty-nine sec- onds, bettering by about thirty-seven minutes the nonstop record established last year by Arthur Goebel and the late Harry Tucker in the Yankee Doodle. Added significance was given to these two achievements by the recent prediction of W. Irving Glover, Second Assistant Postmaster General in charge of Air Mail Service, that within five years the air mail will serve every city of 20,000 population in the United States.

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172 of well being. Williams. they change . . ANect fime say newly shaven skin. there to stay! sensitive _ skins can testify. tic test. It cleanses pores. blades last longer. POPULAR SCIENCE MONTHLY Just notice the fine skins of men who use WILLIAMS!” Keeping your face Fit goes a long way toward creating a feeling The Williams lather goes a long way toward keeping your face Fit. And it gives you real pleasure while you’re doing it. There’s nothing irksome in the Williams shave. With any de- cent razor it’s quick and smooth and pleasant. The Williams lather is super mild—as millions of ultra Its ingredients are triple dis- tilled. It contains no scrap of coloring matter. Close in texture. Saturated with moisture,—containing, indeed, 10% more moisture than any other we know of, by authen- Freshens facial tissue. Makes Leaves the skin Fit. No man’s shaving experience is complete until he has tried No wonder the drug clerk will tell you, “Oh, yes, sometimes . but they all come back to Williams!” THE J. B. WILLIAMS COMPANY, GLASTONBURY, CONN.—MONTREAL, CANADA. , “Williams Shaving Cream please! " Then a dash of Aqua Velva. Scientifically blended to give proper care to the APRIL, 199 Locking Out the Hage and Cold (Continued from page 75) the usual large sheets. These 5 . ache coats geen also help - Pieces the cracks which are likely to a i tering. One manufacturer far. them aoe they overlap when put together. They also ha beveled edges, so that V-joints are formed bot, vertically and horizontally. The overlann: gives a tighter job and the V-joints make f better plastering, as shown in Fig. 2. . While it was decided, after considering points, that insulating board should be just how to use it was still a question, If it were used on the outside only, the eliminatigy of sheathing and building paper would con. stitute a greater saving than would the cost ¢ the lathing if it were used on theinside op] However, tests showed that a covering , sheathing and paper has some insulating yah» of its own, while lath embedded in plaster affords practically none. So to obtain th most insulation for the money a compromig was effected. It was decided to use the sheath. ing and building paper on the outside as usyl and use insulating boards on the inside, plaster. ing directly on them. Of course use on both the outside, eliminating the sheathing, and on the inside, eliminating the lathing, would in the long run have proved a more economical method of construction. f bpoos took care of the wall surfaces. Nex came the question of the roof, an impor. tant factor because of its unusually large ares, Either the roof surfaces themselves could he insulated or the ceilings below them. If the roof itself, the insulating boards could be plied to the underside of the rafters, leaving a good air space between the insulation and the shingles, or they could be put on top of the rafters, and then the shingle strips laid o these. Some authorities say that the greater air space obtained by placing the insulation on the underside of the rafters protects the shingles from dampness and this prevents their rotting, When insulation is applied to the roof sur. faces the attic space is made more comfortable both in winter and summer. But in the Riverside house the attic spaces were to be low and used mostly for storage. Hence it was unnecessary to go to the expense of covering the entire roof area when all the rooms below could be protected by covering the ceilings, Naturally the ideal way would have been to insulate both the roof surfaces and the ceilings, but it was decided as a matter of economy todo only the ceilings. F THIS house had been brick veneer on studs the problem of insulation would have been virtually unchanged, for insulating boards could have been used either to replace the sheathing directly behind the brick, or on the inside of the studs. If the walls had been solid brickwork the boards could have bee used on the inside with furring strips rating the insulation from the bricks. through to the plaster. Insulation, of course, cannot overcome los of heat through cracks around window and house can be made comfortable with insulation no matter what the outside conditions may b€ —and without exorbitant fuel bills. In the case I have described, in spite of long wall surfaces exposed to severe weather com- ditions, the house has been comfortable at all times. And this was accomplished for only about $200 more than the construction have cost without insulation. With the com- would have prevented moisture from coming} door frames where careless workmen have done a poor job. But a firm, tightly-constructed plete house costing, in round figures, $15,000, this proved not a high percentage to spend for an “extra’’ which supplied so much additional comfort. an Ce ge tic cuss well tere knc tage eas) mel son afte pro to t to | wit ing » kne

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LPRIL, 199 coal eat sereie 43 fer & sEE gE8285 ApRiL. 1929 What do You have to sa when you are with interesting people? Can you hold up your end in a general conversa- tion—or are you tongue-tied when with people? oe em the weather has been dis- cussed and exhausted it is only the well informed man—the good talker —whocan hold the attention and in- terest of his friends. Everybodyenvies a good talker. You know from experience the big advan- tage the man or woman has who is an easy, fluent talker. In every-day life men and women who have this per- sonal advantage are popular—sought after. And in their trade, business or profession they are the ones that get to the top. The valuable ability of being able to converse smoothly, naturally and with full confidence is based on hav- ing at your command a fund of ' knowledge that will be of interest to those you are talking to. POPULAR SCIENCE MONTHLY What Worth-While People Are Talking About Today the most entertaining, the most fas- cinating subjects are those that deal with applied science—radio... aeronautics... the automobile; new discoveries in health ... evolution ... electricity. These are the subjects that intelligent peo- ple are thinking and talkingabout. These are the things the worth-while men and women of your town or city are discussing. To make it possible for you and the other thousands of men and women who feel the urge to keep up with the important things scientists have definitely established and the new discoveries that they are making we offer you Tue Pocket Gurpe To Science and 14 issues of PopuLtar SciENCE MonTHLY—all for less than 12 issues of PopuLAR ScIENCE MonTu iy would cost you on the newsstand. Tue Pocket GuInDeE To ScIENcE is written in simple question-and-answer form that edu- cators have found to be the most effective way for telling the known facts on a specific subject. Inthis one brilliant book of 284 pages 173 have been condensed all that you probably will ever want to know about science. You are assured of the accuracy of the answers in Tue Pocket Guiwe To SciENcE, as it was edited by Dr. E. E. Free, who has a remarkable genius for condensing the known facts about the world we live in into short, easily remembered paragraphs. SPECIAL OFFER Tue Pocket Gume To Scienctz is not forsale. It is included, without any extra charge, with a 14 months’ subscription to PopuLar ScreNcE MonrHLY. Poputar Science Monruty “‘carries on” from where Tue Pocket Gumpe To SCIENCE leaves off. THe Pocket Guipk gives you all that the scientists have discovered up to right now—PopuLar SciENCE MonrTHnLy will give you all the important, interesting and new discoveries of science for the next 14 months. It takes over 300 articles and pictures every month to tell the readers of PopuLAR Scrence Montnty all that has happened in the scientific, radio, mechanical and auto- motive fields. Your Name in Gold on this Wonderful Book MONTHLY (regular price by the month would be $3.50) with THE POCKET GUIDE TO SCIENCE—all for $2.95, plus the few cents’ postage. THE POCKET GUIDE TO SCIENCE is bound in beautiful flexible fabrikoid. We will stamp your name in 22-carat gold on the cover of THE POC- KET GUIDE at no extra cost to you if you use the coupon below i diately. We extend to you the Special Offer of a 14 months’ subscription to POPULAR SCIENCE SCIENCE MONTHLY, we will extend your subscription 14 months if you accept this offer. If you are already a subscriber to POPULAR question. Could any offer be fairer? SEND NO MONEY Send no money, just the coupon. If within 10 days after you receive the book and magazine you decide that you are not satisfied in every particular, you may return them, and your en- tire payment will be refund- ed promptly and without Popular Science Maadity 250 Fourth Avenue, New Yor I accept your offer of THz Pocxer Guipe To Science and a 14 months’ subscription to Popu- LAR ScIENcE MontTay. I will pay the postman $2.95, plus the few cents’ postage when he delivers the Poc- Ket Guipe and the first issue of Poputar Science MONTHLY. If the book and magazine are not fully satisfactory to me, I will return them within 10 days and you are to promptly refund my full pay- ment. Fiease stamp my name in gold on the Pocket Gurpe To Science,

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POPULAR SCIENCE MONTHLY Thrilling to Ride as a Thoroughbred There is a zip and dash to motorcycle performance that is unmatched by anything else on wheels. Harley-Davidson’s eager speed on straight- aways, its lighting acceleration, its smooth, quiet rush uphill are the joy of the season- ed rider and the amazement of the novice. Shown above is the latest Harley-Davidson Big Twin—a wonderfully efficient, power- ful, speedy motorcycle that gives sparkling performance at very low cost. Harley- Davidson Twins are priced from $290 up, f. o. b. factory—Singles at $235 and $255. Ask your nearest Harley-Davidson Deal- er about his Pay-As-You-Ride plan. Mail the Coupon for illustrated literature. HARLEY-DAVIDSON Motorcycles HA HARLEY-DAVIDSON MOTOR CO., Dept. P. S., Milwaukee, Wis. . Interested in your motorcycles. Send me free illustrated literature. Name Address ‘ia | | | If Your Headlights ” Went Out— (Continued from page 84) ’ slippery. And lots of new drivers don’t that the roads are much more slippers after the rain starts than later, after th downpour has washed away the slime g.) forms out of the first drops when they re with the dust on the road.” “But if you have chains on the wheels yp can’t skid,”’ interrupted Considine, “Yeah?” growled Gus. “I used to} that, too, when I was just starti B me just thirty-eight dollars to find « wasn't so. I had chains on, but I went a curve too fast on some ice, and the next I knew the back of the car tried to get of the front end. One rear wheel lammed the curb and snapped the axle right off. @ are a help. But you don’t have anyth as much traction with ’em on ice as you, without ‘em when the pavement is dry,” “But you're safe anyway if you enough—and look at all the time ¥ dawdling along,” protested Considine, — “Rats!” snapped the grizzled “You're not safe at any speed on ice with chains, and what’s the use of hurrying a few minutes when you stand a earn a ride in a nice, fast motor hear doing it? a “ AND besides,’ Gus continued, “when § do save a few minutes by tak chances you probably waste ’em right bragging about it! Speed doesn’t cause dents, but speed at the wrong time doe drive always at a speed that you knowis If there is any doubt in your mind, play go slower. . “Going slow isn’t the whole story, You can be a regular old slow-poke and take your life in your hands every time go on the road, if you don’t get wise t biggest idea in safe motoring, and tha Never take a chance on what the other fellow going to do, nor on what he may think ¥ going to do. Don’t depend on your horm other fellow may not hear it. Keep your on the cars ahead, and signal to the f behind what you are going to do. : “TNHERE’S another angle to this § driving business,” Gus went on, af stood off to observe the effect of his operat on the mudguard. “You want to remem that safety depends a lot on the conditig your car. Brakes should be just right an¢ certainly don’t want anything wrong with steering gear. I was in a garage one @ when a hot-air merchant was grumblis everybody about how loose his steering was. But he didn’t do anything about ita little later when he started out, still she off his face, the whole works came loos his hands. Before he could stop, he’d bus into a tree and smashed his radiator. 7 didn’t deserve any sympathy and, believe! he didn’t get it. The gang razzed him it for years afterwardi” F: OR more than three and a half Gus and Joe have been giving ers of POPULAR SCIENCE MONTHLY & benefit of their long experience ¥ motor cars. And each month these® veteran proprietors of the Model G: grow more popular. Many readers k written that the mechanical ady offered by Gus in Mr. Bunn’s enté taining stories have helped them s¢ difficulties which every motorist counters. What is your particull problem? Let’s ask Gus Wilson ab it. Write to Mr. Bunn in care of Populal Science Monthly, 250 Fourth Avenug New York City.