Popular Science Monthly 1930-05: Vol 116 Iss 5

Page 1

‘Par eg N Yu won | 1g { 14 7030 { if) t 4 r - 25cents |) APR 2.1900 |Popular. Se MONTHLY founded 1872 _ America Gets) | Pan ~ ~~ von fe. Oe oii ee DBERGH ve eA eg Goes es 1 aa i. | i Wi by Foxy i] as. soma Do en | se Pee bei THe aaa Hy iy 1b X ty 5 — ,2 3.8 ei A tie | How Lf a i STUNT FLYING} 3 ie Sy Assen Jordanoff | \| + Automobiles /}); eee Home Workshop |||; ‘ “.

Page 2

ae ae LE ST TT Sane pipe eed eee eens ee ee ~ aad le! AE tel GS Ail shane nat BI 8 AS IN SSNS a et There's economy in buying these ° ‘lifetime’ PLUMB TOOLS *S the service that counts; not the initial cost. When a Plumb Nail Hammer will give you years of faithful service, where’s the economy in a cheap tool which —on one job—can waste enough time to pay for a Plumb? The Plumb is scientifically de- signed —a development of hun- dreds of tests with carpenters. It has a full face for accurate nail driving; with the weight cen- tered to give the tool a natural fall; nipper claws that pull even a headless brad; balance that makes it work like a part of your arm; a shock-tested, second-growth hick- ory handle; and that exclusive fea- ture—the Plumb Screw Wedge— which tightens the handle when it loosens, just by a turn of the screw. A tool you'll be proud to own. MODEL HF 81 Price, $1.50 = ° OWER! Accuracy! And P Balarce! You get them all in the Plumb Ball Pein. The head is mounted off- center to give more driving force to your blows; the ob- long eye takes a sturdy, full- size handle; the cone-shaped pein spreads rivets instead of mashing them. The balance gives precision on delicate jobs, and power on the heavy ones. Equipped with the Take-up Wedge which tightens the handle (when it finally loosens) just by a tury of the screw. For work-bench or car, own this finest of all ball peins, MODEL HF 375, 1% lbs. Price, $1.30 PLUMB DOUBLE LIFE Hammers Hatchets Files Sledges Axes especially in a hatchet, is a big asset. With a Plumb you can sink home those long clean blows that get work done. The edge goes where you aim it. Every line of the head and handle, every ounce of weight in a Plumb, is worked out to give that balance that is so vital in an edge tool. peers in a tool, and The entire Plumb Hatchet head is one solid piece of steel — with the edge tempered through and through to hold a keen edge; with the head toughened for heavy pounding; with a broad eye to reduce handle breakage. And, of course, that unique safety feature —the patented Screw Wedge — which enables you to keep the handle tight always. Add this Hatchet to your kit. MODEL 2962 Price, $1.60 AT GOOD HARDWARE DEALERS EVERYWHERE

Page 3

and is a you lean The ery ery » is nce ead ith and rith ivy to of ure the cit. May, 1930 POPULAR SCIENCE MONTHLY Just what is a good used car? BE SURE, men who are thoroughly familiar with motor car construction can tell you whether a car is in good running condition or whether it is pretty well worn out; whether a car is worth the money asked for it or not. But. - to whom should you go for this information and where are you most likely to find a used car that will prove satisfactory and a sound investment? In every community there are dependable merchants whose reputations for fair dealing reserve for them the right to serve you; and for their good service and courteous treatment they are entitled to your confi- dence and respect. | Cadillac numbers its distribu- tors and dealers among this group of substantial and dependable merchants. It is worth bearing in mind—always —that, whether in the sales of new Cadillacs and La Salles or Everybody knows that a good used car 2s a sound investment but who can determine the goodness of a used car even by inspection? the buying and selling of used cars, this highly reputable mer- chant family is alive to the fact that it represents a great manu- facturing institution and that the reputation of that institu- tion for courteous service and fair dealing is in their hands. It is because they are always conscious of this trust imposed in them that the millions to whom they have rendered many services have come to know and believe in them. It is because of this that you may depend upon them for an accurate and honest opinion and a fair price on their used cars. Obviously, it is to them you should turn for a sound invest- ment in a good used car. CADILLAC-La SALLE CADILLAC MOTOR CAR COMPANY Division of General Motors DETROIT, MICHIGAN OSHAWA, CANADA

Page 4

eA NA re ae —e = PSE RSS SR SE ee 4nd» aainaaeiettiesuntbiies. teins. Ta ee ae ae ee — a tab . . abe 2a ae REIS EE DEEMERD NOLL SOO NE LI UES De TT CARY ist BAe =~ se tates ty te Sete emcees Cee 25 Cents a Copy $2.50 a Year Por opular Science MONTHLY S2unded 1872 381 Fourth Avenue New York, N. Y. Table of Contents for May, 1930 LEADING ARTICLES Where America Gets Its Booze . By E.E. Free An interview with Dr. James M. Doran, Federal Prohibition Com- miussioner New Ideas Sweep Movie Studios . By Michel Mok Latest artifices of the movie-makers Hypnotism . . By Harry Blackstone A noted magician says it’ s all a fake **Death Masks” to Solve Crimes . By Hyatt E. Gibson Will new molds of faces and hands replace fingerprinting? Oil Makes the World Go Round By George Lee Dowd, Jr. Little-known wonders of modern lubricants It’s the Nearest Thing to Flying Like a Bird Thrills of riding the wind in “soaring”’ gliders If the Ocean’s Floor Were Dry . . Drawing by B. G. Seielstad A graphic picture of mountains and valleys beneath the sea . . By Robert E. Martin = ewes for America’ s tables - . By Edwin W. Teale Sugar from Sunflowers How experts are seeking a new Do Beavers Rule on Mars? . : By Thomas Elway A fascinating, scientific speculation about life on the Red Planet Stunt Flying . By Assen Jordanoff A noted flyer tells how serial acrobatics have saved his life Monsters That Gulp Iron Ore . Mechanical marvels of Great Lakes conveyors . By Stephen Sherman Circuits That Improve Tuning By Alfred P. Lane Simple ways to increase the radio receiver's selectivity In Radio—Look before You Buy . 4 . By John Carr Hints in judging the worth of a “bargain”’ offer Stop That Fool Honking! Gus and Joe discuss what an euto horn i is for FEATURES AND DEPARTMENTS . By Martin Bunn Cover Design . By Herbert Paus Financial Article Popular Science Institute Page Our Readers Say— New Ideas and Inventions Progress and Discovery ; World-Wide Events in Aviation Popular Science Scrapbook Announcing the Prize-Winners of the ‘‘Five Greatest Inventions” Contest Home Conveniences That Save Time- Editorials ; Helpful Hints for Radio “— The Home Workshop Useful Hints for Car Owners . ... *. 39 Ad 55 56 58 60 12 14 29 Sue 67 70 72 75 & Automobiles _ * in Front of Auto Cleared by xhaust . Psychology May ‘Make Autos Ride Easier. , es i 8 Steel ‘‘Hobble’’ Sets Limit to New Car’sSpeed . ... . “Rattle Meter’? Makes Cheap Cars Quiet Net, Hooked to Car Top, Holds Many Articles , New Brake Tester . Robot Traffic Guide. Vertical Headlight on Engine to Warn Autos .. Gas Tank Locking Cap Will Foil Thieves. New ae Auto Trailer Has Only One ' Elevated Highways ‘to. Traffic Gallon of Oil Runs Diesel Powered Auto 26 Miles Speed Aviation Dropped Flare Lights nai for Pilots .. Lindbergh Goes Gliding Batlike Airplane Will Kar: Load in Wing Graf pe in 50 Trips, Flies 72,000 Miles . Government Gives Michigan ‘Air- port Highest Rating New Plane Resembles a Powered Glider Autogiro from England Has Roomy Cabin Germany Has a “Phantom Air- plane” Electric Flasher Is Used to Signal Piane in Fog . Light Airplane Sets New Altitude ecord. : Strange Events of Aviation Electric Cables Guide Pilots to Port. “Safety Device” Aids Tail Re- pair in Flight Memorial Honors Mother of Air- plane Inventors . Engineering Superchargers Cut Size of Diesel Engines Emergency Dams Guard. Holly- wood . Russia’s Hydroelectric Dynamos Biggest Yet. Huge Turbines Will Give Ireland Cheap Power. A Hydro Plant That Rivals Niagara Falls... 31 38 48 49 May, 1930, Vol. 116, No. 5. ee Science ey ween | is published month- ly at 381 Fourth Avenue, New York, N. Y., by the Popular Science Publishing Co., Inc. Entered as second-class matter Dee. 28, 1918, at the Post Office at New York under the act of March 3, 1879; additional entry as second-class matter at Chicago, Illinois. Entered as second-class matter at the Post Office . Printed in U. 8. A. Copyright, 1930, oy e Popular Science Publishing Co., Inc. Single copy, 25 cents. Yearly subscriptions to United States, its possessions, and Canada, $2.50; foreign countries, $3. The turn of suc authori are not ne of new products of applied science, Po write the business methods of the individuals-or concerns pr use of Popular he Monthly articles for stock-selling schemes is never ized. O Capen, President and Treasurer; R. C. Wilson, Vice-Presi- dent; A. L, Cole” Vice-President and Secretary. contents of this magazine must not be reprinted without permission. The editors sible for unsolicited contributions, and cannot guarantee the re- aterial or insure against its loss. In presenting numerous stories lar Science Monthli ~ 4 does not under- ucing them. The

Page 5

ik Popular Science Monthly for May, 1930 “Sunflower on a Tripod” we Tunnel Surveyors. Rouen Gets World’s Biggest Dredge from Germany . Sixty-Three Centuries of Sky- scra pers Heaviest Welded “Truss Holds Million Pounds . Health and iin Turn of Switch Makes Powerful Antiseptic... Water Blister Fluid Cures Drug Addicts. Doctors Advise Women to Keep Short Dresses. Treated with Health ‘Rays, Ice Cream Cures Rickets_ . New Test Shows Spinach May Contain Vitamin A... 50 52 63 66 30 34 34 38 50 Laboratory Discoveries Artificial Snowflakes Made with Liquid Air Insulator and Conductor in One Substance Found— ue le One of Two Miss- ing Elements Aluminum Best ‘**Sunshine”” Lamps Earth’s Heat Is Not Great 30 Miles below Surface : Models Runs 9-Cylinder Model ages, Size of a Hand Builds 36 Model Ships for War and Commerce . New Ideas in a Racin ing Flyer « a Stagecoach Model Making Sweeps Country . Easy Way to Make Wheels for Model Stagecoach . New Toy Model of Racing Sea- plane . Die Shapes Model Tackle Blocks . Reflector _ for Nature Flashlight Portraits of Wild Life Animals Crossed Pacific 55,000,- 000 Years Ago . Tern Flies 9,000 Miles in Four- teen Months. . Rare Glimpses of the Sleepy Dormouse. oe New aida and Inventions New Fire Escape Device Is Size of Alarm Clock . Overni os Phonograph i in Travel- a ion Machine Plants Sugar Cane New Type Microscope Has Novel Fe eatures . Gage on Square Shows Casting Recess Depth No Ribs, but. Rain Proof. . Air Pads These Boxing Gloves. Cards of Aluminum Look Like Paper... AP ai “Nonskid” Screw Driver . Proving a Singer Can Sing... New Window Glass Brings Sun- light to Dark Rooms. Bricks Twenty Feet Long Made by New Process ._. New Baking Powder Leaves No Residue 34 36 66 66 75 102 113 . 124 132 46 61 62 64 30 32 34 35 35 36 37 50 61 4 D Film ha ease rs Can iad Entire Opera. . Photography Portable Talkies Arrive Vacuum Printing Machine Hunting African Game with a Camera . Film Developed for Movie Finds Carbon in Sun Radio Tiny Transmitter, Sent Aloft, Tells of Winds Radio Tube with Renewable Filament .. ; Radio Squeal Is Music Portable Radio Sounds High Volt- age Warning Auto “Sionals” Bother Radio Stations . Picture Sent 22,000 Miles through Air by Radio Signal to Moon Will Test Radio Range Unusual Facts and Ideas German Foxes Broadcast Their Own “SOS” War Gas Aids Fight on Worms in ‘Church : 25,000 Slices to the Inch . Poison Tested on Insects to Show Fatal Dose f British Railway Car Made of Concrete .. bg New Organs of Thought n Man A Ghostlike Orchestra , Chute-the-Chutes on Rollers . Not a Bolt in This Big Sign .. Wooden Bathing Suits. Man-Made Plapt Yields Stock Food and Paper. ... Tail Lamps for W: alkers . “Galloping Tricycle’ Rides like a Horse . Nonfragile Copper ‘Is ‘Sought as Conductor Stars That Beat Would Burst If They Rotated. How Fast Is It Safe to Come Up? Winged Outboard Motor Craft Sets New Record _. 2,000,000 Persons’ Thoughts Equal One Lamp Power . Rubbish from Streets Paves Ger- man Cities Florida Sees Chance to Grow Rubber. Whale Now Furnishes Leather for eng, : est Map of the World to Be —: in Belgium . Robot Watchdog Fights When Light Hits It ; Electricity in the Air May ‘De- press or Exhilarate : The Art of Chromium Plating Shown in Pictures. New, Big-Yielding Corn Matures in 100 Days .. German National Guard Trained to Use Skis Windiest Spot on Earth Found in Antarctic . Paris Street Cleaners Use se Dustpan on Wheels . 61 31 37 50 30 31 35 36 45 52 66 29 29 30 30 31 32 33 33 33 33 34 35 35 36 36 37 38 38 45 48 48 48 48 50 51 52 61 61 62 4 % Tannin Still in Chestnut Long after Tree Dies . 62 Muscle Teamwork Great Aid to Singers. 62 America’s Spo: re King 62 Find Sardines Spawn ol Califor- nia Coast. . 64 35-Ton Door Guards Berlin Bank Vault . 64 More Tin in Bells, Less Din in Cities . 64 American Bath Day Shifts to _ Sunday : 64 Odd Photos of Unusual Falls . . 65 New Disease hos England Drives Big Do 66 Broken Water Main Gives City a ‘Natural Geyser . 66 Greenwich Clock Keeps Time for dk Rae, Cs For the Home Owner ' Hints on Hanging Curtain Rods. 80 Automatic Holder Grips Broom Handles a” Repairing a Water Tank . . . 126 Woodworking A Card Table by Hepplewhite . 77 Caring for a Circular Saw. . 86 Building a Sturdy Workbench . 94 Two Occasional Tables. i an Builds Modernistic Worktable. . dae Kitchen End Table Holds Extra - ~~ : . 136 Craft: om Secrets of Silver Soldering . . 78 New Finishes for Brickwork . . 106 Tooled Leather Book Cover . . 114 Colonial Doll Cradle and Four Poster 115 Perforated Metal’Sheets Useful in Craft Work . 126 Neat Smoker’s Rack for Holding Pipes... 127 Ideas for the Handy Man Plaster-Molding Soft Metal . . 88 Hints on Making Screens. . . 104 Wiring a Small Garage 108 Shop Storage Tray Simplifies Se- lection of Odd Parts _.. 110 Blueprints for Your Home Work- shop . 111 Varnishes and Dressings in the Home Workshop __. 112 How to Make Cork Bodied Lures for Bass and Trout .. 116 Three-Sided Bird House Has Many New Features. . 120 Electrical Helps for Handy Men . 122 ; = on Applying Paint to Metal urfaces .. 124 Starting Nut in Awkward Position 125 Painting Simplified by Correct Use of Solvents _. 128 Using a Paddle to Mix Paint Thor- oughly Weeteutides Hints of a Veteran Craftsman. 133 How to Make a Money Saving Lumber Order. . 137 Hints for the Mechanic A Toolmaker’s Tips on Drilling, Boring and Reaming s How to Test Brass = Bronze . 92 Old BillSays— .. » ae

Page 6

Se ee AF ph 96 Ny? eee: OF RS SS OE a = - - te a Here is the ANSWER to questions which bother many investors How can you tell what gives a bond absolute safety? How can you get the highest in- come from your money, consist- ent with safety? Why do Chicago bonds give you a highly diversified investment? How can you select a safe invest- ment house? Why can Cochran & McCluer sell bonds in every state of the Union without salesmen? How can you get more than double the savings bank interest rate, with all the convenience? How can you retire in 15 years on your present living budget? All of these questions and many others vital to investors are answered in the new edition of this famous book, “How To Retire in 15 Years.” Get your copy now. We'll gladly send it. No salesman will call. We employ none. MAIL THIS FOR 5 Cochran & McCluer Co. lg is a 46North . oe g Chicago, lil. 370 a a Please send me a copy of the new © gw edition of your famous book, “How ©& gw To Retirein 15 Years.” No salesman © — will call. aes a - Name . a a ee ny ee ” Seceneseees sussssee® Cochran & M‘Cluer Co, Established 1881 Never a loss to any investor 46 NORTH DEARBORN STREET JUST OUT! An Institute Booklet on HOUSE HEATING AND VENTILATING ou know about the many new developments in pa) ods of heating and ventilating? This 40-page booklet will give you full facts regarding the merits of various types of equipment, fuels, etc. and tells how to plan wisely for greatest comfort and economy. Price 25 cents Popular Science Institute 383 Fourth Ave., New York, N. Y. POPULAR SCIENCE MONTHLY P May, 1930 Buying Securities at 85c on the Dollar By CHALLIS GORE, Financial Editor Bank for the twin brothers. Each contained a check for $12,500, the capital sum of their father’s estate, now be- ing given to them on their 30th birthdays. The investment question was foremost in the mind of each, and the variations in their essentially conservative natures so directed their decisions that an interesting comparison in results came to light the next day at dinner. “Look at thelist of stocks I bought,” said Gregory; ‘everyone a leader in its field, diversified essential industries. Ten shares of each, to guarantee me a good income and no grey hairs before my time.” Abbott, the younger looking of the two, glanced at the list, reading it half aloud: “American Can, American Telephone & Telegraph, Anaconda Copper, Atchison, Consolidated Gas of New York, General Electric, National Biscuit, Standard Oil of New Jersey, Union Carbide and Carbon, United States Steel.” “Speak for themselves, don’t they?” Gregory couldn’t conceal the pride in his voice. Abbott’s slow voice doubled the effect of his reply. “Can’t criticize that selec- tion. Own the same stocks myself—along with about 175 others.” “c 1 75 ! ” “Yes,” continued Abbott, “I bought some shares in a general management in- vestment trust and they happen to be holding every one of your stocks. By the way, I’d like to bet I have the better bar- gain of the two. What are you holding American Can at?” “14114” Gregory countered. Abbott smiled. ‘Mine cost me at the rate of $122.07 a share—and I bought it the same day you did.” “Impossible. The low for the day was 140%.” “Just a minute,” Abbott continued, “and I’ll explain everything. Each one of these investment trust shares cost me $55.00. But the assets in cash and securities in back of each*share amount to $63.60. Figure it for yourself. On that basis I paid approximately 86 4c for each $1.00 value, and 86144% of 141%, your price on American Can, is $122.07.” Then Abbott took a pencil and copying off Gregory’s list, tabulated the com- parisons as follows:— Tian were two letters from the Gregory's} Abbott's | Abbott's Tost Cost Saving American Can......... 141%| $122.07) $19.05 American Tel. & Tel....| 237% 205.43) 32.07 Anaconda Copper...... 73% 63 .36 9.89 Ne os eh ga 228% 197.65} 30.85 Consolidated Gas...... 119% 103.15} 16.10 General Electric....... 74 64.01 .99 National Biscuit....... 83 72.55) 11.32 Standard Oil of N. J... 59% 51.35 .02 Union Carbide. ed 91 78.71; 12.29 United States Steel... . 182% 157.86} 24.64 .. SSR P 1,29034| $1,116. 14/$174. 22 “Of course,” Abbott pointed out, “that’s figured out on a basis of one share in each company. On your ten share basis I paid $1,742.20 less than you for my securities. “But don’t jump to conclusions about our relative positions before you consider certain facts. I don’t actually own ten shares in each of the ten companies, as you do. When the trust was organized it issued 275,000 shares of its own stock, for a total sale of about $18,000,000. Some of this money is in the bank, some of it loaned on call, and the bulk of it is in- vested in securities, including domestic and foreign bonds, preferred and common stocks. So my 225 shares represent 225/275,000ths of all the trust’s assets. For example, they own 3,000 shares of American Can, and my proportion is a bit under 2% shares. Similarly, I own a small fraction of their holdings in each of 175 different securities. “Now, if you compute the present market value of these securities, add the cash the trust has, subtract its liabilities and divide the remainder by the number of shares issued, you naturally get the asset value of each share. AsI said before it comes to about $63.60 a share, for each of which I paid $55.00. Then on each share I get $8.60 more in the cash and security value than I paid for. So that my 225 shares total an excess value of $1,935. Or to put it another way, if the invest- ment trust sells all its securities at today’s closing prices, I would receive $14,310— and for that I paid $12,375. “And here’s another angle to consider, Gregory. In a measure I’m protected against fluctuations in the day to day or | month to month market value of my holdings. Because my investment en- titles me to a pro-rata interest in the actual cash dollars which the trust has deposited in the bank. The balance sheet gives the figure as a bit over $1,800,000. According to the figures I’ve shown you. tonight, my share in these dollars cost me a fraction under 86'%c each. There alone I’m in something like $200.C0 over and above what I paid. Gregory was puzzled; the figures were plain enough, but there seemed to be a faulty premise somewhere. He went over his brother’s argument and suddenly re- membered a question Abbott’s explana- tion had prompted in his mind. “I can’t see the reason for the difference in price between stocks bought direct and the price of shares of an investment trust owning the same stocks.” “Neither did I,” Abbott came back, “till Carson down at the bank explained it this way. Popular interest in invest- ment trusts hit a peak last year, and in response, a tremendous flood of issues reached the market, (Continued on page 6)

Page 7

POPULAR May, 1930 SCIENCE MONTHLY Pioneer screening, crushing and loading plant built by Pioneer Gravel Equipment Company of Minneapolis, Minnesota, equipped with ESS Anti-Friction Bearings at all VITAL points. On the Great Hulking Mechanical Monsters of Industry... ALWAYS RING on your real tough jobs...where tons of iron and steel meet other’tons of rock and fight it out for , | the mastery... where speeding trains throw their sway- 1 ing, hurtling masses against railway journals... where weight plus speed combine to conjure up FRICTION to | waste and destroy. Bring them on. Here’s a bearing that seems to like them. Not alone because of the special steels made from ores : from EAISF’s own mines...not alone because of constant . development in SX{SF laboratories...not alone because SSF is the largest bearing organization in the world. But because SX2SF refuses to make a bearing that is one jot less than the best it can produce. Bearings can be built down toa price... but S{iSF will never build them. SEfSF is the highest priced bearing in the world. SKF INDUSTRIES, INCORPORATED 40 East 34th Street, New York, N. Y. aK THE HIGHEST PRICED BEARING THE WORLD 2461

Page 8

ae ee Oe Se tomy ee e wahy chidtlawicddine Atoan ba tee is ono pte eps ~ iteereeens: 42111. ne sat. EEN PETE ARE, ATS eNO SS ee Sy cert alll hse s% =: aia ea : ee aes MONTHLY POPULAR SCIENCE May, 1930 If you read this book you will know how to invest your surplus fs funds Safely Geta clear picture of first mortgage bond investments. See why bankers, professional men and business exec- utives prefer this type of investment. This book which we offer you, free, explains many things that investors, large and small, should know. Mail the coupon for your reply. Jd.U. MENTEER .Presdeme ew INCORPORATED 1913 660 Chemical Bldg., St. Louis 1188 New York Life Bidg., Chicago 378 Colorado Nat’! Bank Bidg., Denver MAIL COUPON TO NEAREST BRANCH Fidelity Bond and Mortgage Co. Send me, without obligation, list of your latest issues. Also, your klec, * “Your Money, Its Safe Investment.” SS - Address ____ a City. State NI PUT ASIDE 54 CENTS A DAY —FOR $2,500.00 OU’LL. never miss this small amount; one fine day you will have $2,500—or more—cash in hand. It will seem like finding the money—it will do some wonderful things for you and yours. More than 165,000 people use the Investors Syndicate plan. Let us tell you about it. Return this ad- vertisement with your name and address for payment schedules and full information. RESOURCES OVER $32,000,000 INVESTORS SYNDICATE FOUNDED:1894 MINNEAPOLIS NEW YORK LOS ANGELES OFFICES IN 51 PRINCIPAL CITIES Buying Securities at 85c on the Dollar (Continucd from page 4) particularly just before the crash. In typical American fashion the public bought more of these stocks than they could pay for out of accumulated’ sav- ings. A great deal of them were pur- chased on borrowed money, placing the investment trust shares in what Carson described as a poor technical position. In other words a large volume of these shares were being carried by people finan- cially unable to hold them through such a violent decline as took place last Octo- ber and November. “Suppose you held ten stocks last Oc- tober, and borrowed $7,000 against them. The crash comes, bank demanding pay- ment of the loan; you can’t meet it. You’re forced to sell your securities. Listen, Gregory, millions of people were caught that way. During the panic the number of people in that position greatly outbalanced those who were able and willing to buy. Prices broke sharply. The best investment trust issues suffered along with the worst. Then again, many investment trust issues were only partly distributed among investors, when the break occurred. You see, while the original sale is being trans- acted the underwriters maintain a repur- chase market to bid for and buy back stock which any investor wants to sell. When the sales tide was at its height, bankers found it necessary to suspend repurchasing all the stock offered. The removal of this support further aggra- vated the extent of the decline. “On top of that came the needless, hysterical selling of securities held out- right by panicky investors who saw prices decline, and dumped their stocks on the market without a bit of reason. Before the deluge subsided, the best investment trust stocks were selling below their intrinsic value. Abbott paused to light a cigarette, and catching his brother’s eye for a moment, could see that Gregory was starting to get the drift of his argument. He continued, “Naturally, the worth of such stock can’t be safely judged entirely by the liquidat- ing value of its assets over and above its selling price. There are other important considerations, among which manage- ment is one of the principle factors. Last year offered a severe test of this. Good management was proved, poor methods exposed. “Even now the securities held by my trust re selling at less than 2% below their original cost to me. Take the Exchange list as a whole and you'll find that the average depreciation in price is a good deal more than that. Strongly indicating that good management held the decrease to so small a figure in face of the violent upheaval that took place on the market last year. And at that, some trusts survived without any loss, though they were mostly outfits that organized and made their investments several years ago, at prices lower than those reached in the crash. “Listen to this clipping from the New York Evening Post that Carson handed me at the bank: “ *The fact that shares of even some of the strongest and most highly regarded trusts are selling below their liquidating values seems almost unbelievable—How long quotations for stocks of leading trusts will continue to lag behind liquidat- ing values is uncertain. Wall Street is confident this situation must soon dis- appear—these stocks under normal con- ditions should sell above liquidating values. for management should command a premium.’ ” Walking home that night, Gregory care- fully reviewed all that his brother had said, and came to the conclusion that while he had certainly chosen his invest- ment stocks wisely and conservatively, Abbott, taking no greater risks than him- self, had gained the better bargain. * * * Note: This article was written March 3rd, at which time some real investment trust bargains continued to exist. It is, of course, impossible to forecast prevailing prices when this reaches the reader. Yet the fact remains that as an aftermath of the panic, cash and securities were ob- tainable, and may still be, at prices representing discounts which may not be duplicated in years to come. To Help You Get Ahead ‘ Booklets listedbelow will helpevery family in laying out a financial plan. They will be sent On request. Your Income and Your Life Insurance is the name of a brief booklet scienti- fically answering the question ‘How much life insurance does a man really need?’’ Provident Mutual Life Insurance Company of Philadelphia, Pennsylvania, will mail a complimentary copy upon request. 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, ll. 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 budget. 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 “se insurance as an active part of your eer for getting ahead financially. Phoenix utual Life Insurance Company, 328 Elm Street, Hartford, Conn., will send you this booklet on request. The Guaranteed Way to Financial Inde- | peninnee tells how a definite monthly savings | as will bring you financial independence. | rite for this booklet to Investors Soalieeen 100 North Seventh Street, Minneapolis, Minn.

Page 9

May, 1930 POPULAR SCIENCE MONTHLY == FF

° 24 -foo hris- O land Sypsy ever enjoyed the freedom of that nomad of the water, Craft uabot, - a e .&., spees the Chris-Crafter. To him the waterways of the whole world lie open. up 055M. P.H. 2850

‘ There are no white lines, no straight pavements. Every bay and river ic invites the Chris-Crafter to rest or to explore, to hunt or to fish. The t ad shorelines offer wide diversity of play and recreation. Thrilling races, : regattas, boat parties, picnics, social aflairs—all are within range of the fast, roomy Chris-Craft dad Every waterside family needs a Chris-Craft, and every

member of the family will enjoy iar use it. It handles even more easily than a motor car and has the same steering, starting and lighting equipment. There are fast, racy runabouts, luxurious sedans, commuters, cruisers and yachts in the 1930 Chris-Craft fleet. C Let the Chris-Craft merchant help you select the if L KY “ond ta { one that fits your desire. Illustrated catalog may World's Lergoet,] Builders of All-Mah ogany Motor Boats be had by writing Chris Smith & Sons Boat s 2 : , Runabouts—Sedans—Commuters— Cruisers— Yachts Company, 365 Detroit Road, Algonac, Michigan. ' 24 Models—20 to 48 feet-—$1895 to $35,000

Shee aanieast eaestce en ntelompibiiagnastiometlbisen. <n saiinitinkinens ; r

Page 10

~— aenalatia 2 PR EE ia EAP aorrer sod a cata Si RAS ALLE GPE LED I TO TN Pn Hi ia Sy Dy, sp Pe Mi bs Mag i ai gs PD: Set =

Se OE a on a RR NS

A ee ce ee ee a

INDEX POPULAR SCIENCE MONTHLY

May, 1930

Guaranteed Advertisements

Automobiles and Accessories Page Cadillac Motor Car Company 1 Carhart Products.. 137 Ethyl Gasoline Corp 160 Houde Engineering Corporation. 79 Oakland Motor Car Company. ‘ 15 Studebaker Corporation of America, The.... 89 Vacuum Oil Co ac 85 Aviation American School of Aviation 148 Aviation Inst. of U. S. A. 157 Detroit Aircraft at Soap 132 Lincoln Ai ying School 146 Marshall ool. 150 Universal ation DIRS 2s 946 sates euame 117 Books i oi ct cereccessenanrens 148 Nelson & Sons, Thos. q Science News-Letter 154 Swedenborg Foundation .................- 140 Building Materials Celotex Company, The.................... 18 Internationa’ Mili & Timber Co. 130 Lewis Mfg. Company..... 137 Masonite Corporation. 13 eS = eer eeer ress re 113 Business Opportunities Carleton Mills, Inc........... sable tan dees 154 Capitol Candy "School = ; : 148 Central States Manufacturing Co ; 144 Crowell Publishing Co, The ... ‘ 147 Faté, Root, Heath Co.. gas : 155 Foley Manufacturing Co. .122-152 Hobart Bros. Co ; 154 i . ., Ge saceoeeeneeedaake 124 Seer 148 National Sales Mfg. Co... .............. 157 Newcomer Associates.................. 149 I I EID... cc ned cccnaccocesace 136 R & B Specialty yar sepia 149 Rollo Specialty I, ov inwebucomenn 146 a I a SE -S22 92 148 Uron Associated Industries .................. 140 General American Telephone & Telegraph Co........ 87 Folmer-Grafiex Corp...... 116 General Electric Co............ 95 Silent Automatic Corp.................... 111 Western Electric Company................ 11-105 Williams Oil-O-Matic Seting Corp eee 119 Hardware Supplies Boston Varnish Company... . 131 Casein Mfg. Co. of America, The 120 Nye, Inc., Wm. F. 118 Plastic Wood.. 158 Rutland Fire Clay Co 118 Savogran Company 128 Smooth-On Mfg. Rs Se ba Rihegi eaten a aw domains 126 Industrial Equipment American Screw Co oa 114 Fafnir Bearing Co., The................. 83 i. + 6 0a dee wee me eden 128 Grinnell Company Third Cover Norton Company 99 ee ee NEN, BD... ices ve vdbesceces 5 Veeder-Root Inc. PE eWEe alanaeeaerae a 124 Investments Cochran & McCiuer Co... .... 6... cc ccceeee 4 Fidelity Bond & Mortgage Co. 6 Ng caw bc sce de eae saeuae 6 Miscellaneous EE re re 130 Bureau of Inventive Science................ 152 Du Maurier Company..................... 126 os 5 oo 06 4 dv eens ecemens 136 Onan & RE an wae o4 0:Gln cba Saw 146 EN. Sc se ccccsassesecicestid see 124 EEE, . dec ceaassetsseves 120 RS SE a SEE ee Reap ae eer ee 132 Musical Instruments Buescher Baad Instrument Co............. 124 eg oe eee eee ial duaretats 132 Holton EE fy” Ace's ves ccesesc 136 Patent Attorneys Coleman, Watson E. Dieterich, Albert E. vans &. Company, Victor J. Fisker Mfg. Company, Adam Gottlieb, Edward. a S Wie Peer secoecccccce McCathran, Irving L.. O’Brien, Clarence A. Randolph & Company.

Popular Science GUARANTEE © POPULAR SCIENCE MONTHLY guarantees every article of merchandise adver- tised in its columns. Readers who buy products advertised in POPULAR SCIENCE MONTHLY may expect them to give absolute satisfaction under normal and proper use. Tools, Radio Apparatus, Oil Burners and Refrigerators ad- vertised in POPULAR SCIENCE MONTHLY have been tested or investigated by the Popular Science Institute of Standards and each advertisement carries the insignia indicating ap- proval. However, other products advertised in the magazine not subject to test carry the Same guarantee to readers as products tested. THE PUBLISHERS

Radio Apparatus Aluminum Company of America............ 103 Electrad, Inc. : 132 RCA Radiotron Co. 81 Razors, Toilet Articles, Etc. American Safety Razor Co.,................ 108 Autostrop Safety Razor Co. 128 a Bid ai oleae via sonia © & aarermrnss 115 Electric Razor Sales Corp. of America... ... 139 Gillette Safety Razor Co................ : 10 Lambert Pharmacal Co.................. 17 MI IOI. go osc ccc cc cwcsnccccdnes 138 Se eee ae ee oe 109 Procter & Gamble Jagararesiewn BEES 120 Williams Co., The J. Bu... . 1... cc cece cees 123 Schools SCE PET EEE COTE POPE 144-146 Bliss Electrical School..................... 150 NN Sr rere reer re. 144 Chicago Technical College................. 150 Columbian Correspondence College......... 146 Cooke School of Elec., L. L..............5-5 147 Coyne Electrical School................... 157 weg — SA A ee 149 ra 6a Sd. 5 4:6 Waa eins ace 149 Federal School ae ae 143 Finlay Engineering College................. 148 First "iemaiion Conserv. of Music.......... 154 IID, «0 5 vc ccccssscdbisvecess 145-149 Greer tecnica es Gb uipcpseddids Jensen 140 High School Home Study Bureau........... 152

Schools (continued) Page International Correspondence Schools... .. . 144-150 Landon School of Cartooning.............. 154 La Salle Extension University............. 154-157 Lederer School of Drawing................. 154 McCarrie School of Mechanical ed 0s 112 Greenfield Tap & Die Corporation.......... 136 ree 126 —- Mfg. Co., The Russell............. 137 ydole Hammer Co., The David.......... 106 SE WD GOI. nc cce ce cecces 100 Nicholson File s nomen des 102 Porter, Inc., H. K.. 140 North Bros. Mfg. Co.. 107 Simonds Saw & Steel Co. . 124 South Bend Lathe Works... . 134 Stanley Rule & Level Plant, The........... 121 es Se rrr 91 Trimont Manufacturing Co., Inc........... 139 » eI rere 97 I as BM o.oo ac oasis s saignee sees 130 Woodworking Machinery Co., Inc., The..... 134 Wooster Brush Co., The................... 94 Typewriters, Writing Materials, Etc. International Typewriter Exchange......... Spors & Co., Frank 152 136

Page 11

1930 122 over 52 36 POPULAR SCIENCE MONTHLY 9 May, 1930 “Immense Range of Topics... And fverything | Ujp-to-Dare” JSG. Schurman, formerly President, @rnell University “™, “My children “™ use it intheir NELSON’S ™ school-work PERPETUAL LOOSE-LEAF and find the ENCYCLOPAEDIA Woot Cannot Grow Old! their questions Nelson’s 22 years ago recognized that an Encyclopaedia bound, stitched, and glued in the ordinary re a d j | » way is inevitably out of date soon after it is published—because of the constant development of y NEW KNOWLEDGE and the rapid changes going on every day. So Nelson’s originated the ; oa loose-leaf reference system that keeps the Encyclopaedia always up to date. The Nelson Loose- GW fvan 5.Consulting Mining Engineer, Seattle ,Wash. DS a a a @ a ,

Page 12

Oe ee) re nee ee oe eterna ai PT RN PES. Be VEIT eas Cs ae = ORS IP St: PR LEE er Ee ~- ~ te ~~ 10 POPULAR SCIENCE MONTHLY May, 1930 6 Vital Improvements ... what a difference they make in your shave es Gillette r ‘ z = a 1. Reinforced corners % Pa 2. Cut-out corners 3. Rust-resisting blade 4. Newshape guard teeth 5. Square blade ends 6. New guard channel No WONDER millions of men have thrown away their old razors for this New Gillette. Its reinforced razor cap and cut-out blade corners abolish “razor pull.” Its specially processed new blade resists rust. You merely shake it dry— no more tedious wiping—no more cut towels. Then there are the new shape guard teeth, new guard channel, square blade ends—six reasons in all why the New Gillette gives you the fastest, smoothest, most comfortable shave you've ever had. Here is your chance to have the greatest bargain in shav- ing comfort and convenience that $1.00 has ever bought: The $].00 for ten and The New Gillette Razor, 24K. gold New Gillette Razor, 24K. gold-plated, in a handsome leather ee oe plated, in a beautiful case, complete ‘|= : - The New Gillette th New Cillette Blad Pri case, and one New Gillette Blade. Additional new blades are Biaietetiienn, ae €...frice priced the same as the old, one dollar for ten, fifty cents for green packet Other De Luxe Models at $5.00 to $75.00 five. Your dealer has both waiting for your call. GILLETTE SAFETY RAZOR CO., BOSTON, U.S.A. The New Gillette Shave

Page 13

May, 1930 Pre s00 POPULAR SCIENCE MONTHLY Everywhere at the same time! ryw Public Address System brings speaker right to 0U —— The speaker rises—and the Western Electric in- stallation in the huge room transforms him into a score of speakers! No matter how far away from him you sit, his every word comes to you as dis- tinctly as though he stood right beside your chair. Committees arranging banquets or conventions find that meetings are more interesting and effective when held in_ hotels where the Public Address System widens the hear- ing circle. This equipment is a miniature interior broad- casting station, transmit- ting speech, music and entertainment within a build- ing—to as many rooms as desired. Patrons of hotels thus equipped find an added attraction in getting music “on tap” in their rooms via loud speaker. In up-to-date schools, hospitals, railroad stations and amusement parks, too, you will find the Public Address System adding to convenience and enjoy- ment. Made by your telephone makers, it assures the faithful tone and dependable service for which Western Electric sound transmitting apparatus has been known for over half a century. Western Electric ij PUBLIC ADDRESS Distributed by Graybar Electric Company 3 ¥'S TF Bes. amen MAKERS OF YOUR TELEPHONE ncsneriemneesnaiarliianichienythentnntiemeentee pill amioagig

Page 14

Pr. NER MN eT ee ~ LISLE LAGMBRE EN LEN TIO ONE RN a a 12 POPULAR SCIENCE MONTHLY Is It a Refrigerator or Just a Box? By F. G. PRYOR Seeretary, Popular Science Institute NLY five years ago, refrigerator () buyers were asking for good-look- ing cabinets, big enough to hold the family’s supply of perishable foods, not too expensive, and not too hard on the ice. That was what they asked for, and that was just about what they got. Today, there are quantities of real re- frigerators being made and sold, and we refer not only to the satisfactory me- chanical refrigerators on the market but also to the excellent refrigerators of the ice type now available. This has all come about as the result of public demand. A few years ago, when the buying public was aware neither of the advantages of proper food preservation nor of what good refrigeration consisted, manufacturers were obliged to comply with the demand for cheap, attractive looking but poorly built boxes. The majority of refrigerators made then came under this classification. For the discriminating few who required real refrigeration, a much smaller line of refrigerators was made. They were necessarily high priced because they were manufactured in limited quantities. The market presents a different picture now. An increasingly large proportion of consumers are coming into stores today and asking for refrigerators insulated and constructed so as to be real refrigerators— that is, maintain a temperature not over forty-five degrees Fahrenheit in the milk compartment and an average temperature not over fifty degrees Fahrenheit in the large food compartment when the out- side temperature is at seventy-five de- grees Fahrenheit. Prospective buyers now ask to see a section of the refrigerator wall and they discount any sales talk of ‘‘air-space insulation,”’ demanding a sub- stantial thickness of some good insulator. Pees refrigerators are available today at lower prices than ever before be- cause of better design and quantity production. Improvements have been made in interior design which add much to the efficiency of the refrigerator and comparatively little to its cost. Good refrigerators now have a long baffle, which makes for better air circulation, and prop- erly dimensioned ice compartments. The trade is merely following public demand in this respect. One of the great- est chains of department stores in the country recently threw out all refrigera- tors in stock that were not insulated and replaced them by those that met the re- quirements of the up-to-date purchaser. In line with the general progress in refrigeration is the effective work under- taken by the American Standards Asso- ciation. This body joined with about fifty organizations in working out re- frigerator standards and the work, which has been under way for two years, is nearing completion. The organizations represented on the Committee include May, 1930 the Bureau of Home Economics of the United States Department of Agriculture, the American Home Economics Associa- tion, the purchasing departments of the United States Army and Navy, the National Association of Ice Industries, the American Institute of Refrigeration, and a number of others, including Popular Science Institute. Under the leadership of the American Standards Association these organizations are setting definite standards for various grades of refrigerators so that a buyer may know whether he is getting an A, B, or C grade refrigerator, or whether the box he is considering is not even entitled to be called a refrigerator. POR example, through the activities of this standardization group, a re- frigerator buyer will soon be able to go into any progressive store handling re- frigerators and ask for a box having, say, five cubic feet of food space, and he will be given a choice of an A, B, or C grade refrigerator. Any one of the three will be sufficiently well built to prove durable and maintain proper temperatures. How- ever, if the buyer can afford the higher initial price of the A-grade box, he will be able to do with twenty-five pounds less ice than if he took the B-grade, and fifty pounds less than with the C-grade. The A-grade box will be of finest con- struction and insulated with two inches of corkboard or its equivalent in any other satisfactory material, while the B-grade box will have but an inch and one half of corkboard and the C-grade only one inch. To offset the increased heat leakage into the more thinly insulated boxes, they re- quire proportionately larger ice chambers for proper temperatures to be maintained. While the advance in home refrigera- tion during the past few years has been great, and much good will result from the work now being done by the organizations mentioned above, there still will be con- siderable room for improvement in refrigerating conditions while so many families remain unaware of the import- ance to good health of proper food pre- servation. Dr. M. E. Pennington, Direc- tor of The. Household Refrigeration Bureau of the National Association of Ice Industries, estimates that only fifty per- cent of the homes in this country have any means of refrigeration and only one tenth of this group have real refrigeration. INSTITUTE BULLETINS Refrigeration for the Home* House Heating and Ven- tilating* Insulation in Building Construction* List of Approved Tools List of Approved Radio Equipment List of Approved Oil Burners Advice on Installing Oil Heat *Starred bulletins 25 cents M

Page 15

1930 f the ture, 0Cia- f the the tries, tion, Dular rican tions rious uyer i, B, the itled ities re- > go re- say, will ‘ade l be ible Ow- her | be less fty on- ; of her ide ch. ito re- PTs ad. ra- en he ns nh- in ly - MPO wey Nene”

In reducing factory costs and improving products, these same qualities of Presdwood make it almost invaluable. It does not crack orsplinter, can be nailed near the edge without «: splitting, and is readily worked on punch press or band saw. Helps keep eggs—or hatch ’em

Presdwood makes iceboxes and incubators, bee hives and iQvat VY bird houses, shipping containers and breakfast nooks, table Cnicks tops and bookcases, kitchen cabinets and speed boat decks. It lines concrete forms for stately buildings, provides perma- nently beautiful paneling for the finest homes. Manufacturers, sign makers, builders and home mechanics should read the Presdwood booklet and examine a sample of Presdwood. Both the booklet and sample are sentto you, Free, without obligation. Just clip out the coupon and mailit in NOW.

MASONITE CORPORATION 111 West Washington Street Chicago, Illinois

| ssascunne CORPORATION Dept. D5, 111 West Washington Street, Chicago Please send me, Free, a sample of Masonite Presdwood and the Presdwood | - | asonite par !

ae: | eee Made by the makers of iin nssnininicssnenceietihinianiilciaanentbcaaiiiiemal State.. sl napaiainiidaadidaiall MASONITE cabeounan INSULATION | _ ie

Page 16

Tete eee ee oe are eats tet es is» etter a0 nae AMIR LRT TIVES SEE RRL EIR SO UU A WE Sat 14 OurKea Here Are Two for the Book Ir tHat “What’s Wanted” book of inven- tions that you used to keep is still in existence, here is an invention that seems to me perfectly possible in this mechanical age—much needed and yet, as far as I know, not available. That is a simple home outfit for recording your own phonograph records. We have home movies and home radios. Why not a home phonograph recorder? What bud- ding musician, for in- stance, wouldn’t like to make a record of his own playing on the piano or piccolo or even— friends willing—on the saxophone? And baby’s first words could be reserved to be played years later. An even- ing’s dinner table conversation might be worth playing over in later life. The wonder, it seems to me, is that no satisfactory home re- cording outfit is available. P.S.—A friend of mine asks me to include another suggestion— a timing switch for the electric light, to be used in printing photographs, that will auto- matically shut the light off after an interval of, say, one fourth of a second to two seconds. —G. F. B., Passaic, N. J. Where Are the Whiskers of Yesteryear? IN LOOKING over the pictures of the eminent modern scientists who will award PopuLar Science Monrtu y’s $10,000 prize, I notice that not one has a beard. Then I turned over the page and saw the photograph of the in- ventor of the pneumatic tire hiding behind a bushelful of whiskers. I’ll bet he had to stop every block or so to untangle that beard from the sprocket of his bicycle. Or maybe he tucked it in his vest. When I think of all the trouble long whiskers must have been, I nomi- nate, as the greatest modern invention, the safety razor!—J. A. U., Chicago, Illinois. But Where Would You Park? I was at a motor boat show one night recent- ly and when [ came out I happened to look up at the sky and see the planet Mars. It was nice and red as usual and although I couldn’t see the canals, of course, they gave me an idea. Why not have canal sys- tems for our modern cities, with neat little motor boats plying swiftly or gently as the spirit moves them through the silvery thor- oughfares? All the noise, dust, and general hub- bub of automobile traf- fic could be at least alle- viated, and the majority of citizens might be glad to use this means of getting about when they weren’t in any special hurry or had no enormous load to carry. Anyway, so far as speed is con- cerned, these new water runabouts seem to be able to hold their own. And would water high- way construction necessarily be more expen- sive than that of asphalt or cement? Even if it were, wouldn’t the romantic background POPULAR SCIENCE MONTHLY thus provided be worth the cost? Besides, think of the contribution to civic beauty if several of our cities should be turned into modern Venices on a large scale.—E. C. G., New York City. Your Fish Isn’t a Fish I noticep H. W. M.’s letter in the February issue of your magazine describing the fish he has. I am under the impression that it is not a fish but an aquatic batrachian. The batrachians are related to the amphibians, but differ in the respect that the amphibians will probably die on land and drown if they remain too long in water. The batrachians stand midway between the reptiles and fish, and are divided into three classes: 1 .The Anura or tailless. 2. The Apoda or limbless. 3. The Urodela, taking in newts, salamanders, etc. There are several unclassified specimens of the Urodela—and I think it is to this order that H. W. M.’s specimen belongs.—I. A. B., Berwyn, Ill. Try This Revolving Cage HERE is a problem I would like someone to work: In a fixed roller bear- ing A (diameter three inches), a shaft S (diam- eter two inches) revolves upon rollers R (diam- eter one half inch), which turn in a cage C. How far will the cage turn while the shaft is making one complete revolution?— J. B., Bozeman, Mont. Another Way of Saying It's Push, Not Pull FOLLOWING an article which appeared in P. S. M. some time ago, there seems to be a little misconception in regard to the wings of an airplane. The trend of the article was ap- proximately this: a partiak vacuum is created by the curve on the upper surface of a plane’s wing and the resulting suction affords two thirds of the lifting force. R. A. L. gave a wise retort in January’s number. But since the same error has appeared in several other periodicals lately, I take this opportunity to offer a solution. First the ancient idea that Nature abhors a vacuum must be discarded. Pressure is exerted upon the underside of a plane’s wing due to the atmospheric pressure from beneath. This would be increased also by the force of the wind. If there is a partial vacuum on the upper wing surface, there is no opposing force, and the wing is pushed upward —from beneath. Therefore the total pressure or lifting force is on the under surface of an airplane’s wing. This is merely the simple application of a law of physics. I hope the obsolete theories will be forgotten and this so- lution accepted.—T. R. L., Worcester, Mass. May, 1930 Where’s the Joke? Micuet Mok’s recent article on “New Clues to the Mayan Riddle” is certainly a joke. It seems to me he just came to life, or perhaps the fuss was because it was the first time Lindbergh saw the Yucatan ruins. I think that Colonel and Mrs. Lindbergh and some of their friends received a vacation all dished out in first-class order. He didn’t dis- cover anything new. The only thing new was that it was the first time Lindbergh had seen them.—B. Z., Bluff City, Kan. Just a Little Dip into Infinity SPEAKING of problems, I have an easy one which I am sending you: An automobile went around a mile track, the first time in one minute. Every lap following it went in two seconds less time. How many trips would it make and how long would it be before it would go around the track in no time at all?—A. C. K., Attalla, Ala. Just Eager Waiting EAGERLY every month I await the arrival cf your magazine. Your Home Workshop articles are great and I am especially interested in the new series of splendid and delightful models Captain McCann is presenting.—J. W. K., Marietta, Ohio. After All, You Know, You Can't Blame Father Some of the reasons why I don’t like your magazine are: My father brings it home and there is such a rush for it that I never get to see it. Then when I do, it has so many inter- esting articles in it that would just do for my general science note- book at school, and my father won’t let me have them! He says it’s such a good magazine that he’ll punish the one that cuts it up. So I wish I had never seen your tempting magazine, or that you wouldn’t put such good articles in it. —‘*Tempted,’’ Canal Zone. If They Didn’t Quarrel Why Start Things Now? I Quite agree with H. L. R., of Richmond, Va., in his letter re the invention of the electric incandescent lamp, and beg to amplify it. Sir Joseph Swan, of Newcastle-on-Tyne, ob- tained his patent for an incandescent carbon filament lamp at least twelve months before Edison, and the lady who helped him died re- cently in England at eighty-four years of age. There was much discussion between the two inventors as to priority of patent, and Swan eventually came to the United States. The result was he and Edison shook hands, and the May,

Page 17

930 Lew ya , or irst and all dis- vas een ne the rit ny me Ir d [- POPULAR SCIENCE MONTHLY A FAMOUS NAME A FINER CAR THE NEW SERIES SEALE Rs. 962 x of its pri In its remarkably sound and sturdy engine you will find a typical example of the extra value offered by the New Series Pontiac Big Six. This fine power plant is the biggest used in any six of Pontiac’s low price. It de- velops 60 brake-horsepower which accounts for Pontiac’s exceptional swiftness, tremendous power on hills and flashing acceleration. Pontiac has a moderate speed engine, achieving its great power output at only 3000 r.p.m. As a result, the New Series Pontiac Big Six is excep- tionally dependable and economical, for its power plant gets less wear per mile of driving, and therefore lasts longer. Maintenance cost is reduced to a minimum as a result. Notable features of the Pontiac engine are its big durable bearings, the sturdy crankshaft which has the Harmonic Balancer to counteract ‘ Olen ae the biggest engine used in any torsional vibration, full pressure lubrication, crankcase véntilation which prevents condensed water vapor from diluting the engine oil, and the new rubber mountings which assure smoothness of operation by insulating the engine from the frame. If you are mechanically inclined, you will enjoy an inspection of Pontiac’s big engine. Mechanical-minded or not, you will get a real treat, we believe, from a trial drive. Note also the new riding comfort afforded by its improved Lovejoy Hydraulic Shock Absorbers—the new ease of control in its roller bearing steering system. Balance all these features—including its econ- omy of operation—against its low price and you will then appreciate the great dollar-for-dollar value offered in the New Series Pontiac Big Six. Prices, $745 and up. All prices f. o. b. Pontiac, Mich., plus delivery charges. Oakland Motor Car Company, Pontiac, Mich, Write for an interesting booklet which illustrates and describes the design of the New Series Pontiac Big Six ONTIAC six *745 PRODUCT OF GENERAL MOTORS ... BODY BY FISHER

Page 18

—em © Se 16 first lamps they jointly produced were known as “Ediswan.” The “Ediswan” company still exists. Why should not credit be given where credit is due? Swan is never mentioned on this side of the water.—S. W. R., Ottawa, Canada. Would Pin a Medal on Us Your announcement of a $10,000 prize and a gold medal to be awarded for the achievement in science of greatest value to man- kind interested me greatly. As an old reader may I offer the suggestion that not the least achievement in the world of science has been the recent popularizing of science, the awakening of the mind of the layman to the tremendous part that science plays in his life? In this work PopuLaR ScieENCE Montuiy has played a leading part. You need not go beyond your own office in your search for a deserving candidate for your award.—L. L. F., Jr. Rochester, N. Y. As Fast as Possible I HAVE been a reader of this magazine for several years and [ think it is getting better every issue. I am greatly interested in furni- ture designs and models of all kinds. Give us more of them.—C. E. C., Westminster, Md. Perpetual Motion Is Killed Again IN A RECENT number of PopULAR SCIENCE MonTuiy Mr. S. P. N. R., of Dayton, Ohio, wants to know what would prevent an over- balancing perpetual motion wheel, one side of which was insulated against gravity and the other side not, from turning. Here is the answer: The same natural law that kéeps the moon from turning would also keep the wheel from turning. If you, Mr. S. P. N. R., had made the trip around the world on board the Graf Zeppelin with your overbalancing wheel, you would have found it out.—G. H., Cotulla, Texas. Scotland Wants a Ship in a Bottle ° I am at last doing what I meant to do a few years ago —write to congratulate you on the splendid articles you publish in PopuLAR SCIENCE MONTHLY. Through the kindness of a friend in the U. S. A., I have been able for the past three years to read and en- joy P.S.M. every month. I have read every page and have derived much knowledge from doing so. I take this opportunity to congratulate Cap- tain McCann and the Radio Editor on the clearness and simplicity of the reading matter: and the drawings in their departments....I wonder if I am asking too much when I ask if you will publish drawings and explanatory matter for the making of an old-time sailing ship in a bottle. That is one of the things I’ve long wanted to make.—A. McsS., Renfrew, Scotland. Was the Ant Crazy? Wuat establishes the synchronism of the ant and the turning of the log to cause that ant to travel the length of the hypotenuse of a right triangle with sides twelve and five feet re- spectively equaling thirteen feet? Einstein states that there is no such thing as a straight line; then how in the world can the lowly ant POPULAR SCIENCE MONTHLY trot a straight line on a rolling circular plane arriving at the end of the log at the instant of stopping. Scientifically absurd.—H. F., Tul- lahoma, Tenn. Delightful, But— Not Surprising As AN indication of how I value your maga- zine, I may state that for a number of years I have followed the practice of clipping and indexing all articles which are likely to prove of value to a man who owns a house and car and who is forever “making things.” I find that I get more such articles from POPULAR ScIENCE in one issue than I do from any other magazine in ten or twelve.—F. G. S., Ottawa, Canada. What a Memory! ANTHONY FoxKKER claims to have made the largest land plane ever built, On page 57 of the July, 1928, issue of PopuLar SCIENCE MONTHLY are two pic- tures of a giant all- metal trimotor plane built and flown in Eng- land. It has a 150-foot wing spread and seven- and-a-half-foot wheels. The Fokker had, I be- lieve, something like a 95-foot wing spread. The craft is called the Beardmore Jnflexible. It weighs fifteen tons and has a total of 1,950 horsepower. Am I right?—W. B., Palo Alto, Calif. The End of Colds As My contribution towards science I offer as a positive and absolute preventative of “bad colds” the constant and persistent habit of breathing deeply and exclusively through the nose. Cold germs, microbes, and the like cannot get a foothold or thrive and endure in fresh air. The remedy, then, is to keep the mouth shut and breathe exclusively through the nose.—N. L. F., Walhalla, S. C. Why a Skyscraper Record? TuarT letter from J. A. O. on the need for rules for skyscraper records has a point. In New York City, two new buildings are nearing completion. It was claimed that each would be the tallest in the world. During the summer, the plans for both’ buildings were altered secretly on two occasions to add a few feet to the height. In the end, after it was too late to change again, one skyscraper tacked on a steel spire, 185 feet high, and carried off the palm. I’m hoping the other building will put up a spire with a lightning rod at the top and cop the victory.—E. F. W., New York City. IIis Two Motors. Pulled Full Load IN THE January issue I noticed an inquiry by A. E. W., Ada, Ohio. I solved the same prob- lem in the following manner. I took two motors of the same type and speed and then disconnected the starting coils on one motor. I got a three-inch pulley with set screws on each end. The motors were then connected together as in a motor generator set. They were mounted on a base with the pulley in the center. Both motors were wired in parallel. By using this method one motor starts them both and when they are up to speed both are pull- ing full load —L. G. S., Boise, Idaho. May, 1939 Will the Air-Minded Answer This Attack? THE airplane, as a safe means of transporta- tion, is, and always will be, in my humble opinion, a failure. This statement will be greeted with jeers by many of the readers of : POPULAR SCIENCE MoNnTH- eg LY, but let us consider the matter from a cold- ly practical viewpoint, guided by experience and the laws of prob- ability. Conceive, if you can, of a monorail New York Central Railroad sys- tem. As long as a train is in motion it maintains its erect po sition, but when it stops, it falls over except where provision is made for holding it right. Therefore at each station auxiliary rails are provided which engage wheels on the sides of the train. These rails extend outward from the station a sufficient distance to permit the train to attain a speed of, say, thirty miles an hour. The monorail track extends from city to city, in a cut or on a fill, according to the nature of the terrain. Imagine yourself on a monorail train de luxe. Everything is lovely until something happens which necessitates a stop between stations. Of course, nothing of that nature is supposed to happen, but for some obscure reason it does happen. The train will topple over and probably several will be killed. Does any reader of PopuLaR SCIENCE MonTuiy think people would trust their lives to such a railroad system? To determine the value of the airplane as a means of safe transport, just substitute airplane for monorail train in the foregoing description. Does it sound like a safe way to travel? Are you will- ing to trust it? But keep your eye on those lighter-than-air ships they’re building down at Akron!—H. H., Mattoon, IIl. Eyeglasses the Penalty for Civilization I was interested in the letter ““Too Many Eyeglasses?” K. N. B. raises an interesting question. It is most likely that the eye structure varies little from that of our early ancestors. Further _ investigators are agreed that the hu- man eye was primarily adjusted for viewing objects several feet or more from our eyes. Under the stress of modern conditions our eyes are being used: at near distances, say thir- teen to sixteen inches for a great part of the time. Nature has made some physiological adjustments for these changing conditions but in many cases the changes have not been sufficient to meet the needs. Thus the use of glasses is one of the penalties which we pay for our civilization.—G. H. A, Houston, Texas. Would Esperanto Help the Talkies? In your editorial about the impossibility of sending American talking films to foreign countries you ask for a solution to the problem. It is hard to answer, but consider this propo- sition: In the International Auxiliary Lan- guage, Esperanto, every letter has everywhere and in every manner the same sound. The language can be learned in a very short time and a vocabulary of 500 words is enough.— L. E. McK., Altoona, Pa. NOW AM civitrzeEedD? - rm -_ oF

Page 19

May, 1930 POPULAR SCIENCE MONTHLY 17 ‘Why Frank-—how disgusting! F you, or any member of your family have the slightest evidence of dandruff, we urge you to try this treatment, which has benefited thousands:— Simply douse Listerine, full strength, on the hair. Vigor- ously massage the scalp forward, backward, up and down. Repeat this treatment for several days, using a little olive oil in case your hair is excessively dry. You will be amazed at the speed and thoroughness with which Listerine gets rid of dandruff. Even severe cases that costly so-called “cures” failed to improve, have re- sponded to the Listerine method. We have the unsolicited word of many to this effect. There is no mystery about Listerine’s success used this way. Dandruff is an infection caused by germs. Full strength b. (ee Note to Medical and Dental profession: When prescribing a mouth wash for germicidal pur-. poses, please make certain that it is a germicide: and not merely a prepara- tion which is only deodor- ant and astringent. Listerine is powerful against germs—though so safe it may be used in any body cavity. Indeed, Listerine’s germicidal action is so intense that it kills 200,000,000 of the virulent S. Aureus (pus) and B. Ty- phosus (typhoid) germs in 15 seconds—both noted for their resistance to antiseptics. Yet its effect on tissue is healing. Naturally then, Listerine is effective against other in- fections of lesser nature. Use it at the first sign of dan- druff. Lambert Pharmacal Co., St. Louis, Mo., U. S. A. LISTERINE sets rid of dandruff The safe antiseptic Kills 200,000,000 germs in 15 seconds

Page 20

ee Serene er Sead PI 9 oP Nee re FOr NPT A TOT PEE Ra A hi at a te pe ee A ms 2 i lS A Ne Sc eg eal e etl Se ia BOY artim sng mage sanyo Seely OT 5 cee TI oS ee label ak ele Se ee a EO eS — A eee meen: Sara or. ee ee ne wee 18 How it sounds to your NERVES The rattling din of typewriters in busy offices . . . the shrill jangle of telephones . . . slamming of doors and drawers .. . the constant hum of conversation ... These distracting noises bite into nerves wornraw from thestrain of business routine. They encourage costly mistakes ... hamper the clear thinking of people paid to think. POPULAR SCIENCE MONTHLY PERMANENT QUIET FOR YOUR OFFICE UNDREDS of progressive busi- ness men have found an easy way to subdue this annoying din. By applying Acousti-Celotex to their office ceilings they have succeeded in subduing noise —in raising the efficiency of their entire organization. Acousti-Celotex is a noise-absorb- ing cane fibre tile that comes in rigid units which are quickly applied to the ceilings in old or new buildings. The natural buff color and trimness The Celotex Company maintains an acoustical engi- neering service with which all architects are familiar. Acoust! — (ELoTEx FOR LESS NOISE—BETTER HEARING City of these units add to the beauty of any office. Acousti-Celotex is easily cleaned —the upkeep cost is low. If desired, it can be painted and repainted even with lead and oik paints to conform with any decorative plan, without loss of its sound-absorbing value. Hospitals use Acousti-Celotex to produce the restful quiet that speeds convalescence. Schools apply it to classroom and assembly hall ceilings May, 1939 Five 703 to subdue distracting noises and reverberations. Churches and thea- ters use it to assure proper acoustics. Mail the coupon below for addi- tional information. The Celotex Company, 919 North Michigan Avenue, Chicago, Illinois. Mills: New Orleans, Louisiana. Branch Sales Offices in many princi- pal cities (See telephone books for addresses). In Canada: Alexander Murray & Co., Ltd., Montreal. The word CELOTEX (Reg. U.S. Pat. Of. Ree SS uu —— Chicago, llincle THE CELOTEX COMPANY 919 North Michigan Avenue, Chicago, Illinois “Gentlemen: Please send me further information on the use of Acousti-Celotex.

Page 21

OOTLEGGERS are the only people in America who have adjusted themselves completely to prohibition. Providing America with alcoholic drink is now a well organized business with an in- come estimated at over three billion dollars a year. It has its executives, its salesmen, its technical experts and traffic special- ists, its lawyers, its financiers, even its code of ethics. It is illicit, under cover, but not unrespectable; only some of its lesser hirelings are that. Its existence is an economic and industrial fact to be reckoned with. Alcohol for the bootleg trade is now made, thousands of gallons at a time, in great fermenting vats and modern rec- tifying stills. No chemical engineer would be ashamed to own this equipment as the by E.E. FREE Dr. James M. Doran, head of the Treasury Department Unit for enforcement of the Volstead law. product of his skill. There is a good reason for this, as the present bootleg- ging industry is able to hire and, I am informed does hire, to direct the indus- try’s operations and design its equip- ment some of the ablest technical experts on fermentation and distillation. FEW weeks ago in Springfield, Illi- nois, two of the country’s largest and most respectable industrial concerns, the Fleischmann Yeast Company and the Corn Products Refining Company, were indicted for conspiracy in furnishing, the Federal grand jury alleged, yeast and corn sugar to illicit distillers of alcohol. The point is not the guilt or innocence of these concerns in selling their products or in knowing how their products were to be used. The significant thing is the nature of the materials referred to. Mil- lions of pounds of sugar are being diver- ted, it is charged by the Government, into this new, enormous industry of illicit fermentation and distillation. N 1929 prohibition authorities raided nearly sixteen thousand distilleries and seized over eleven thousand stills, many of them giant affairs two or three stories tall. Houses looking like private dwellings on the outside are found to have been gutted, the tall columns of stills run from basement to attic, fermentation vats holding thousands of gallons in- stalled, and the whole interior converted into a modern, not inefficient alcohol fac- tory. Other stills by hundreds have been built in old, converted factories; in garages with the still columns, which 19 +5 i a he Py Si ie 6 ae sintalindaniadtttaaminiintaiiamsadimameta den mau + nals yeaa

Page 22

set ap RA a ret ee ees fos - . nt pena any aliowvets S te a ee eee pe! SN ERE EO Hi te URN FOR: tM flak Rite i TURNS cl NS — Snare pAvdiniaae’ ie k 4 * F | " : Se. ae Te BSiae Pn A er ls SUIS ey Oh aS DCEO, TOR BRE SI hae S. Wren 20 The size of these raided stills shows big capacity for production of alcohol. must have height for good opera- tion, cut through the floors from basement to upper stories; even in farmers’ barns, where the tall cylin- ders of adjacent silos make excel- lent places for the columns of the stills. ——- se 2 at HIS increasing industrializa- tion of illicit alcohol was the burden of the answer made by Dr. James M. Doran, well-known chemist and now United States Prohibition Commissioner, when I asked him to tell me for PopuLAaR SCIENCE MONTHLY where America’s booze is coming from. I have con- firmed the Commissioner’s state- ments from many sources. I have asked officers of agencies opposed to prohibition, police officials, pro- hibitionists, Congressmen, _ bar- tenders, bootleggers, and court officials who deal frequently with prohibition cases. All opinions are the same. Dealing in illicit alcohol is big business and is organized as such. This fact is changing the ways of get- ting alcohol. When prohibition went into effect, Dr. Doran told me, there was much liquor in storage in bonded ware- houses and similar places. Owners were allowed to retain this liquor, for medicinal sale or for.any other legal use. At that time, too, bootlegging and illicit manu- facture of alcohol were new businesses not yet organized. “a HESE facts combine. to direct the first flow of illicit liquor out of ware- houses into the hands of small, ill-organ- ized distributors. Stores of whisky and other liquor were rifled, with or without the consent of the owners; guards were bribed; individuals even went so far as to buy whole warehouses full of other people’s whisky, and then steal the prov- erty for which they were responsible, cheerfully paying damages when they fell due, as the profit on illicit sale was great- er than any possible legitimate damages. This first phase of the bootleg industry lasted, I gather from statistics and other facts presented to me by Dr. Doran and SPs eS sey op ha ~ Peo cA AO a’ = 5 ee d - ? a ; + POPULAR SCIENCE MONTHLY his officers, for two or three years after the new law went into effect Jan. 16, 1919. By 1922 or 1923 most of this stored’ liquor was gone. The former legitimate distilleries were closed. All the ware- houses either were too well guarded by honest officials to be reached or already had been rifled of their contents. The budding illicit industry needed a new source of supply. : This was found in denatured alcohol. Alcohol is one of the world’s most im- portant industrial chemicals quite aside from its use in beverages. Even before prohibition, the production of alcohol for the manufacture of extracts, drug com- pounds, lacquers, antifreeze mixture for automobiles, and other chemical uses far exceeded its use in whisky and practically equaled the amount of alcohol drunk in wine and beer. Nowadays the American chemical industry has so far expanded that it uses nearly twice as much alcohol as was distilled for use in beverages— except beer—before prohibition went into effect. Even before 1919 much of this indus- trial alcohol was “denatured,” that is, chemicals were added to give it a bad May, 1930 taste or a bad smell or to make anyone who drank it ill. In those days this was done to make such industrial alcohol exempt from the tax laid on alcoholic beverages. Little time was wasted in an effort to make these original denaturing formulas proof against reconditioning of the alcohol, as no chemist, at that time, could have any object in taking the trouble to remove these evil tasting things from cheap denatured alcohol, since he could buy good alcohol for only a few cents more, an amount consonant with the federal tax. When the supply of illicit whisky stolen from warehouses began to grow short, the bootlegging industry, as Dr. Doran told me the history, turned to this denatured alcohol. Chemists had no great difficulty in removing the added materials from the denaturing formulas then in use, leaving reasonably pure alcohol. Gradually this alcohol began to Moonshiners in the mountains of the South always made booze, but under prohibition they have increased their operations enormously as is shown by these stills which can turn out five gallons of alcohol in eight minutes. replace, in the bootleg market, the mate- rials stolen from the warehouses. It is not necessary, the uninitiated should be informed, for a bootlegger to have whisky, gin, brandy, and all the rest in order to supply his customers with what they want. Any liquor and many wines can come out of the same alcohol barrel. HERE is great outcry at present about “synthetic gin,”’ yet seldom has America seen anything else. Real gin is generally supposed to be made by fer- menting the berries of the juniper and distilling the product, just as whisky is made by fermenting and distilling a “mash” of water and grain, or brandy by fermenting and distilling grape juice, or rum by fermenting and distilling a mix- ture of sugar and water. That was the theory about gin. Once, before prohibition, I tested (be- ing then a practicing chemist) one bottle of gin which apparently had been made in that way-- But then, as now, virtually all the gin drunk in America, no matter how foreign and pretentious the label, was made synthetically out of juniper oil, other flavoring matters, and alcohol.

Page 23

1930 1yone S was cohol vholic in an uring ng of time, the sting ‘ohol, only nant hisky grow ; Dr. ) this 1 no dded nulas pure in to eir PS. ate- t is 1 be lave t in rhat ines el. sent has n is fer- and y is ndy ice, nix- the be- ttle ade lly ter el, ol. May, 1930 The blending, it is true, was better than now and sometimes the blended product was redistilled or aged to improve the flavor; re- finements which the present-day industry has not yet reached. But all American gin, practically speaking, was just as “synthetic” fifteen years ago, before prohibi- tion, as it is today. Also it was very little more wholesome, for one thing that the present well-organized bootleg- ging industry has learned is that it is not good business to poison one’s customers. Little of the booze now on the American mar- ket is really unwholesome, assum- ing that any booze is wholesome. Probably there were about as many instances of poisoning from bad liquor in preprohibition days as now. At present, at any rate, This carload of illicit beer, seized and dumped by pro- POPULAR SCIENCE MONTHLY of making it, except by mixing malted grain with water and then setting it aside letting nature take its course. Probably the present method of making all these things to order out of cheap, easily stored ex- tracts and raw alcohol must be considered an industrial improve- ment. Great store used to be set on “aging,” and it is true that to keep a raw distilled liquor in a wooden barrel charred to char- coal on its inside does destroy, in the course of time, certain chem- icals, like fusel oil, which may exist in natural whiskies distilled from fermented grain. Though that is an advantage for real whisky, it can do synthetic whisky little good. If the maker starts with pure alcohol, dilutes it properly, and adds nothing harm- hibition officers, suggests the quantity now being made. ful, accidentally or otherwise, it is chiefly not poisons but alcohol, just the same as it always was, that sends heavy drinkers to the hospitals and the casualty lists. AS TO taste, it is not possible to con- gratulate the present industry so highly. Today not only the gin, but the whisky, brandy, liqueurs, and other drinks are made from raw alcohol “cut” with water, which merely means diluted, and then flavored with special mixtures of chemicals, plant extracts, or other materials to make the final liquid taste like Scotch, rye,’ absinthe, or whatever the trade demands. There is nothing new about this. Liquors have been made that way for years. I am not sure that it is not just as good a way as any to make these materials. One reason why the Scotchmen on their moors and the Irishmen on their peat bogs made whisky in the traditional ways was that they had no alcohol and no way aging will not make the result- ing whisky, gin, or brandy a better or less harmful drink. Anyway, the present bootlegging indus- try makes and distributes a very fair quality of booze, virtually all made syn- thetically out of raw alcohol. In 1923, and for a few months thereafter, this alcohol was coming, I have explained, from the chemical reconditioning of the various kinds of denatured alcohol then on the market for legitimate industrial purposes. Up to that time, the activities of the Governmental enforcement officers had been devoted largely to guarding the warehouses and trying to catch the thieves. As the source of supply shifted, the prohibition officers shifted around too, and arranged to make more and more difficult the reconditioning of the denatured alcoholic materials. Dr. Doran admits, and every chemist will agree, that it is quite impossible to put into alcohol any poison or other denaturant that another chemist cannot A high-class bar of preprohibition days. Distilleries and breweries furnished the liquor for such bars, but even then, it is said, most of the booze was no better than the modern bootleg brands. 21 % remove. Chemical analysis, to which the majority of chemists devote their lives, consists in just this taking apart of dif- ferent chemical substances after they have been mixed. But what the pro- hibition authorities could do and did do with the denaturing formulas was to make them more difficult and more costly to take apart. Most of the denatured alcohol now sold, for example, is made according to an approved formula known as number five. Of this alcohol, intended chiefly for anti- freeze mixture in automobile radiators, forty or fifty million gallons are sold each year; about as much alcohol as was in all the whisky, gin, and other hard liquor sold before prohibition. This material contains, as the denaturants added to the pure alcohol, about four percent of wood alcohol, a small amount of kerosene or gasoline, and a similar small quantity of a special denaturant called Aldehol, which is composed of certain simple chemicals that are related to alcohol itself but are not drinkable. rs IS possible to take these denaturing materials out of the alcohol again and leave the latter reasonably pure. All that is necessary is a large and complete dis- tilling system, a skilled chemist, plenty of time, and the labor, fuel, and patience necessary for redistilling the material over and over again, sometimes from cer- tain added chemicals, until all of the harmful substances have been removed. That is precisely what a chemist does, in fact, when he wants to analyze one of these denatured mixtures. The only trouble with this procedure, from the viewpoint of the bootleg barons, is its cost. No industry will buy its raw materials in a dear market if it can find a cheap one; and that brings us to the present period of big-business bootlegging. By 1926 or 1927 the efforts of the pro- hibition authorities to tighten up the for- mulas for dena- (Continued on page 146) a a ar ad X — £ A SEE TSS a eT ae f. ; ; | 4 f ke { a ft 4 iat het hf } 7 . if 4 “hl : at Be ty F aa | + 4 i pe | | 7 4 i : i gee tate gS 7 ; - ~ hone vthetimane tener ae Peer genimeen memes amen, styrene bane: 7 “

Page 24

Tiara ices toe . PO eR Cen, OAR BED. Seas SBR CCE OPIN: & At ISLE LIE LIRA BE! FE TOA AGILE Se ate AABN Wi 2 L me iu swe « co etd ae ee. €2 el an a eee * i ee a SS ES RAE ANS pena me ST a ee eS ee a aee i Tah aes Begs pe - 2) cin ee, 5 a es = SSS = ——— none 9 “~w?eN A year and a half all motion pictures will be wholly or partly in color. Three years from now the black and white photoplay will be as rare as the silent picture is today.” With these words, the head of the production de- partment of one of Ameri- ca’s largest motion picture corporations recently gave me a glimpse into the literally brilliant future of the film industry. His prediction was based upon a new and revolu- tionary development in picture making. Producers have discovered that the public is enthusiastic over color and that it means money at the box office. Hence, “color” is the watchword in the world of the cinema today, just as “sound” was three years ago. Four all-color musical motion pictures, photo- graphed and printed by the so-called technicolor process, are attracting huge audiences on Broad- way, New York City, as this is written. Many other talkies and “singies,”’ mainly in black and white, have tinted sequences. A year ago On with the Show, the first all-color talking and singing picture, start- ed the color rush. This year no fewer than 100 feature-length pictures, entirely or partly in color, will be shown in theaters throughout the country. To meet this heavy production sched- ule, the Technicolor Corporation, which makes the colored movies for the various producers, has just completed a fifth large plant in Hollywood. It has two other laboratories in the picture colony and two in Boston, Mass. Eventually the new plant, costing more than Movie bel POPULAR -SCIENCE MONTHLY New Ideas Sweep Studios By MICHEL MOK $1,000,000, will have a capacity of 47,000 feet of colored film a day or about 14,000,000 feet a year, enough to prepare more than 2,000 prints of feature films, the average length of which is 6,500 feet. LL of the technicolor plants are working triple shifts and _ thirty special technicolor cameras, operated by trained crews, are rushed from studio to studio and kept grinding night and day. This sudden demand for color pictures May, 1930 Battery of cameras that photographed Song o? My Heart, in which John McCor- mack is starred. Note the large “Grandeur” camera in the center. All cameras are muffied to still the sound of their mechanism. In fore- ground, Mr. McCor- mack and Frank Borz- age, director of the film. is a direct outcome of the great success of the talkies, which, begun in 1927 asa desperate experiment by a producer who was in financial straits, are now presented in 12,000 of the 20,000 moving picture theaters of the country. Sound pictures, it is claimed, have added more than 10,000,000 persons to the weekly cinema audience of the United States and increased re- ceipts thirty-five to forty percent. But sound did more than that. It an- swered the old question: What is wrong with the movies? It was this: the public was tired of the silent films. The satura- tion point had _ been reached; the industry was stagnant. It needed a new and vivid element of appealing interest. HIS is the lesson the producers have taken to heart. They are not to be caught napping again. And there is sound reason for their watch- fulness. According to sta- tistics recently compiled by the International La- bor Bureau, at Geneva, Switzerland, $4,000,000,- 000 is invested, through- out the world, in the mov- ing picture industry. Of this staggering sum, half belongs to American concerns. Movie men, therefore, are eager to add to their bag of tricks any potentially successful new development. Recently there have been other revolutionary in- novations aside from color. One of these is the greatly enlarged picture, taken on wide film and projected on a huge screen. This was introduced to New York a few weeks ago when the Roxy Theater gave the first showing of Happy Days, a so- called “Grandeur” production made by How pictures for the wide screen are made on standard film by the Douglass process. Left, a picture made on standard film with an ordinary lens. Center, same scene shot with lens that compresses wider angle of view on film. Projected with special lens, this appears as at right.

Page 25

the ies, sa In Ow the ure is ore ons ma ted rty did an- on: the the the pen vas of the cen not ing ind ch- ta- led La- va, gh- oV- valf to lly tly in- ese en. ‘ew ive so-

May, 1930 the Fox Film Corpora- tion. Photographed on film seventy millimeters wide, twice the standard width, this giant photo- play was flashed on a screenforty-twofeet wide, filling the entire breadth of the Roxy stage. The ordinary screenistwenty- four feet wide and eight- een feet high. Grandeur films add _ twenty-five percent to the height of the picture. RODUCERS do not claim that Grandeur pictures are three-dimen- sional, which they decid- edly are not, but they do say, and justly, that they create a somewhat stere- oscopic effect. There are twofactors that causethis illusion. First, it is more natural and comfortable for the eyes to take in a scene spread on a wide surface than one on a narrow one. Secondly, the edges of the picture, because of the great width of the screen, are less obtrusive or entirely eliminated. The new wide film has two real ad- vantages. Because of the greater terri- tory covered, more persons can be shown clearly on the screen at once.

This is what the studio people saw as a Schufftan picture was being filmed. The members of the choir and organist were in place in the set.

ey” \ . TRANSPARENCY OF CATHEDRAL INTERIOR POPULAR SCIENCE MONTHLY

SILVER REMCVED FROM / FRONT OF MIRROR TO ALLOW IMAGES OF CHOIR AND ORGANIST | TO SHOW THROUGH | AND BLEND WITH m REFLECTED CATHE- PRAL PICTURE

Diagram makes clear how the studio set shows through the mirror with silver removed so its image can blend with the reflected picture. be a combination of color, wide film, and sound. From reports current as this is written, it seems likely that, outside of New York City, the “high, wide, and handsome” pictures will not be shown

This is especially valuable in NEGATIVE COLOR SCREEN PRISM SYSTEM ° . 1 CUTS ITS SIN the now popular picturized : )ReD= BLUE ANO IMAGE INTO side k 40 VIOLET LIGHT _» TWO COMPLETE _ ~*~

musical comedies, in which big groups of chorus girls and dancers are presented. For the same reason outdoor pano- ramic views become more effec- tive and beautiful. The second advantage is that the width of the film allows for a wider sound track. One tenth of an inch is all that can be allowed on standard film. On Grandeur the sound track is one quarter of an inch wide. This produces a better sound quality and re- quires less amplification. Also less magnification of the pic- ture itself is necessary, result- ing in sharper and less “grainy” images. Naturally, the next step will

ANGE (COLOR SCREEN CUTS IN FULL COLOR ‘ Le ) ‘ FILMS INKED WITH CHEMICALLY PURE

IMAGES gids vephie oe

OFF ALL RED ANO ( rosmrives MADE FROM LLOW LIGHT ELTERNATE NEGATIVE | FRAMES TO GET | SOLID ROW OF | AS

“RED IMPRESSION TRANSPARENT COLOR A simplified diagrammatic explanation showing, step by step, the prin- ciples of the technicolor process from the studio shot to the finished film.

Orn. ‘PRINTING } /. ROLL { This is what the audience saw when the optical mirror picture, at left, was thrown on the screen. for some time. The reason is that the “big four” of the industry—Fox, Para- mount, RKO, and Warner Brothers—as yet have not agreed on the exact width of the enlarged pictures. Such agreement is essential because presentation of the big movies will force the theaters to acquire new equipment such as projec- tion machinery and screens. In many cases introduction of wide films would even entail the remodeling of the stage or the entire house. 4 he. Fox organization, the first to release a wide picture, insists on a seventy millimeter film. On the other hand, the Spoor-Bergren film, controlled by RKO, is sixty-five millimeters wide. What width the other two concerns favor is not known, .but their opinions, too, seem to be divided. Moreover, the big producers are reluctant to saddle the additional cost of wide picture equip- ment on the exhibitors, many of whom are carrying heavy financial burdens due to recent installation of apparatus neces- sary to present sound pictures. For the time being, probably the only novelty at your favorite movie house, unless you happen to live in New York City or in Hollywood, where one theater also is equipped for the showing of Grandeur features, will be color pictures. To be exact, it will be the only development you will be able to see from your seat in the theater. But “‘be- hind the screen,” or rather, in the studios and laboratories, new tricks of movie magic are photoplay quality and by cutting the cost of production, increase the number of fine pictures. The Bell Telephone Labo- ratories in New York City, which were the greatest factor in making sound pictures pos- sible, having developed two of the three principal talkie de- vices now in general use, are seeking constantly to improve their products. Their latest (Continued on page 143) i a = = ~ ows ~ ~ : Pye oo, —_— 4 ee orn a a ee ee eam => nase antiaettie ta we cae od Ai nce Re an <ewe Sat eSctee eet coir apmnaslemenrcenat Ye ~ao a eS — os ipeapecemnaneey 6 . % . rs A Bie, fai emia aaa Si tia wef BASES TEI SETS = a és FOE eet 4 = ‘ nee - =o See xr cn ape ne ee ee en eae ee . " eae Jes suns + ~ * Fg oe Se ene ae es re ORS eT SR = Se ee Baten ia le Ean a ni . ameee le IZ y erin nas ‘ i - Pee “ Aenea R UE ARATE EAA DOD TIES) OECD OIOTIT op RE EY NN mm being introduced to improve. - aeeth

= — ae

Page 26

5 LN A TES et

ee ee : Se Pale ee PEE PRL EOLA SIT 1 ARIE NGO BOE CNIOIE

~ =

nen talniniaeaicaeankeeet cs FREE OD

re es ey RRS ewe

ee TE PES RR TPG Sa = oe ee ara) 3 a as

eae:

The hypnotic “falling test,”

POPULAR SCIENCE MONTHLY as demonstrated by Blackstone. He describes this stunt as merely a case of lost equilibrium on the part of the subject. HAT is the truth about hypno- tism? To this question Wesley R. Wells, professor of psychology in Syracuse University, has given, in the Marchissue of PoPULAR SCIENCE MONTH- LY, an answer with which I emphatically disagree. Patient investigation of all kinds of so-called hypnotic phenomena has con- vinced me that there is only one correct answer and it is this: The truth about . hypnotism is that it does not exist. Because time and again it apparently has been demonstrated, thousands of sin- cere and intelligent people believe in this imaginary force. Because they found it a likely peg on which to hang mysterious happenings that they could not other- wise explain, a number of medical men and psychologists have taken it seriously and sincerely believe in it. As a matter of fact, hypnotism is nothing but a high-sounding name for a form of strong suggestion. For example, Professor Wells tells how he hypnotized a college student, making him believe

that a half-dollar placed:on his forearm was a red-hot iron. Naturally, I believe this report made by such a distinguished scientist, but I refuse to believe that hypnotism was involved. The suggestion seems to me no more remarkable than many others not attributed to hypnotic influence. : I know of a negro who had stolen some grapes and eaten them and who then overheard the owner of the vines say that he had sprinkled Paris green on the grapes. He intended to worry the negro, and he did. The thief became violently ill and suffered great agony. Obviously, there was no hypnotism in this; there was just the power of suggestion working on the imagination. EAR, bewilderment, absent-minded- ness, and even stupor or temporary indifference to surroundings or pain are states of mind experienced by nearly every human being. While in one of these conditions, an otherwise normal person frequently will behave in a strange or unexpected manner.

LS/11 May, 1930

Fake, says.< magician replys to a scientist who calls it “i e al sites BLACKSTONE N OUR March issue, Wesley R. Wells, professor of psy- chology in Syracuse University, gave his views on hypnotism. Harry Blackstone, the famous magician, read Professor Wells’ article and sent us the following comment. Since it is the policy of PopuLAR ScIENCE. MONTHLY to open its columns to those who have made independent research in any field of science, we present Mr. Blackstone’s reply as an interesting exposi- tion of the other side of a much- disputed question. Those who believe in hypnotism seem to think that simply because one of these familiar states of mind happens to occur under unusual circumstances, it proves that the condition is the result of a peculiar power called hypnotism. F THOSE who hold this belief were to say that there are certain ways in which one person may encourage fear, bewilderment, absent-mindedness, or stu- por in another, they would hit the nail on the head. Suppose I suddenly thrust a loaded revolver against a man’s ribs. Governed by fright, he may behave in a number of unusual ways, but he will not be hypno- tized. If I make the same experiment with an unloaded gun, he will probably be just as frightened. Should I use a toy gun, many persons would be so terrified as to be incapable of distinguish- ing between a real revolver and an imi- tation. There are others in whom the sudden action of the bare hand, without

Page 27

1930 1O US Ils’ ing icy [LY ose ant ce, e’s S1- ch- t of e to , in ear, stu- nail ded ned r of no- ent bly ea ish- mi- the out May, 1930 either pistol or toy, would produce the same degree of fear. Yet there would be no hypnotism about it. It merely would be an illusion created in the mind of one person by the convincing action of an- other person. Loss of memory (amnesia) and in- creased memory (hypermnesia), men- tioned by Professor Wells as states that may be induced by hypnotism, are com- mon mental occurrences under normal circumstances. NDER the stress of excitement, many persons will forget the most important matters. A name, as familiar to them as their own, will slip their minds. The boy who has his recitation letter-perfect forgets it. when he steps onto the platform. Cases of suddenly increased memory are also frequent. Some long-forgotten _inci- dent, name, face, thought, tune, or story will spring into one’s mind at the most unexpected mo- ment. The actions of the hypnotic “operator” simply tend to induce such states of mind. If his “passes” or other antics are dis- turbing, the ‘“sub- ject” will become ex- cited and naturally be susceptible to forget- fulness. If the “sub- ject’’ is not disturbed, but is lulled into a contemplative state of mind, he will be apt to remember past events. In speaking of “passes,” Professor Wells* states that face-stroking manipu- lations made by the hypnotist are intend- ed to bring about a re- laxed and drowsy state, such as one may experience when in the barber’s chair, enjoying the manipu- lations of the barber. This fits in exactly with my conclusions. The barber is not a hypnotist, yet he is getting the same re- sults. When the hyp- notist does produce unusual effects, it is because he takes advantage of a men- tal condition that the “subject” might have attained in a barber’s chair. Linking automatic writing with hyperm- nesia, Professor Wells gives an instance of a student who, under “hypnosis,” wrote down past events that he had forgotten. Automatic writing, like sudden flashes of memory, is a common mental reac- tion. Thousands of people draw queer geometric figures, faces, and diagrams or write apparently meaningless words while waiting for a telephone connection or listening to an uninteresting discussion. POPULAR SCIENCE MONTHLY Is that hypnotism? Of course not. It is chiefly absent-mind- edness. Hypnotism has been defined as ‘an extreme form of absent-mindedness.”’ It may also be called an extreme form of fright or bewilder- ment. When I was about eighteen years old, I joined a committee from the audience that was invited to come on the stage during an exhibition given by “Professor” SS ESS 2 ea ay Se . Ars : The professional hypnotist’s confederate, when laid with his feet on one chair and his head on another, arches his back and becomes a human cantilever that can support great weight. Flint, famous “hypnotist.”” Two of us were standing close beside the performer, and he quickly looked us over. = ORK with me, boys,” he whis- pered. “Do everything I tell you. See me after the show; I’ll fix you up.” We entered into the game and did all the foolish things the professor sug- gested. Afterward, we went to the stage door and were paid. The professional hypnotist uses vari- ous artifices to make his ‘“demonstra- tions” appear effective. Troublesome committeemen he classes as “unsuitable subjects,” thus disposing of them. Those 25 The subject’s head is forced back until it can be held with one finger. In this ition it can’t be raised and the trick works. remaining are persons he can easily deceive, or who will work with him on request, and his own “plants” or “horses.”” He depends upon these “horses” for his most sensational tests. Placing his finger upon a person’s fore- head, the hypnotist says: “Close your eyes. Keep them closed. Look upward without opening . your eyes. Now! You can- not open your eyelids! You cannot open them! Try! 9 The ‘‘subject ’’makes the attempt and fails. Wonderful! But no hypnotist is necessary. Any one can try it for himself. It is virtually impossible to open the eyelids while the eyes are raised. A professional hypnotist can make a normal person stutter. He tells his “sub- ject” that he cannot talk without stutter- ing. The “subject” denies this. Then the hypnotist gives him words to repeat aloud. The “operator” begins to stutter over the words, and soon the “subject” is doing the same thing. This is a very convincing test. Yet it is purely a case of clever suggestion. A somewhat nervous person will become confused and in his embarrassment will experience, under suggestion, the un- certainty suffered by the chronic stam- merer. (Continued on page 148) alll enapsaninesmn pr irene sar agate ter me + Se AES ae “ if {i i : r oe pe

Page 28

ee ee PR eo y - 4 M " ROT) SAINI OH LOT Nl EB a a AB th tay oe a A A Rs it er nditnnneteleindteheeieenin omiauinne st Eee ene ISELIN PO IDE CA OS ee 8 — ne ee oe ne ete ee Re AER te ee ee Codie tne wind ee p evtr tne 5" 36 ak nwt ot 9 Soeenger? 26 “Death Masks” to Solve Crimes Negacoll cast of Vienna murder- er’s hands. They are very lifelike. By HYATT E. GIBSON len to twice its normal size, the body of a young man was found some weeks ago in a woods on the outskirts of Vienna, Austria. He had been strangled. The savage imprints of the mur- derer’s fingers were still visible on the throat. There was not a mark of ‘identification on the victim. \) The police took the body to the % morgue. A hurried telephone call was made. Ten minutes later a tall, stoop-shouldered, bearded man en- tered the mortuary chamber. Peer- ing through tortoise-shell spec- tacles, he examined the corpse and silently set to work. From a bag he produced a box containing a sub- stance resembling chopped raw meat. This he heated, allowed ‘to cool, and then with quick, dexter- ous hands he applied the material, now extremely flexible, to the murdered man’s face and neck. The hair he cov- ered with the stuff by means of a broad- mouthed syringe. In half an hour the job was finished, and that same afternoon the victim was buried. Next morning a bust of the dead man, startlingly accurate in every detail, in- cluding the murderer’s fingerprints, was delivered at police headquarters. Within a week, the victim’s relatives identified the cast, and a few days later the police, with the fingerprints as a clue, captured the criminal. That was one of the first successful tests of a new method of crime detection and identification devised by Dr. Alphonse Poller, Viennese anatomist. Since then, the police of the Austrian capital have adopted it and discarded the Bertillon fingerprint system. For Dr. Poller’s mod- eling material, which he calls “negacoll,”’ and the composition of which is a secret, can be applied with facility to the living or the dead. The Viennese rogues’ gal- lery now resembles an old-time dime museum, filled with reproductions of the faces, noses, ears, and particularly the B ies to twice | the neck swol- POPULAR SCIENCE MONTHLY hands of all manner of lawbreakers. ‘Already several crooks have been trapped through these “death masks”’ of the living. In many ways negacoll is. supe- rior to clay and other substances used in making plaster.casts. Fash- ioning a cast of a living person is a lengthy, laborious process involving the danger of suffocating the sub- ject by closing his pores. With negacoll a head may be reproduced inside half an hour. The usual death mask presents only a sketchy likeness; the hair, for example, is never copied successfully, and to duplicate the back of a head is next to impossible. Through its ex- treme plasticity negacoll produces an almost incredibly exact image of the subject, showing each in- dividual hair on the head and the tiniest line in the face. In casts of the hands, the whorls on the finger tips are so distinct (Continued on page 156) May, 1930 Dr. Alphonse Poller, Viennese anato- mist, whose new method of making death masks of the living identifies criminals. In making a cast of the top of the head, the negacoll is put on with a syringe. Above, the cast, in which note the distinctness of the hairs. ak RE >, This cast was made of a victim strangled in a forest near Vienna. From it the dead man was identified by relatives several days after his burial. Fingerprints on neck helped find the murderer.

Page 29

May, 1930 POPULAR SCIENCE MONTHLY 27 Oil Makes the World Go Round

The thermometer, above, tells the engineer if the lubrication is sufficient. If the gage is above a certain limit it is a danger sign and shows the need of immedi- ate increase in oil supply. At the right: These three giant 12,000-kilowatt gen- erators operate upon single massive bearings at the top. Experts had hard work finding just the correct lubricant to keep them running smoothly. Below: This heavy duty factory machinery runs slowly, but the job of find- ing the right grease to use on it was just as important as getting the proper oil for fast moving engines. ey » Ricey Sie os . gh, —— —— { ¢ . 4 | Do you know what lubricant does and why it is true that all your comforts and even food de- pend upon it? This article shows what smooth running wheels mean to our civilization and why if they stop men will starve. By GEORGE LEE DOWD, JR. EN Army airmen from an east- ern air field join the Caterpillar Club, by leaping from. disabled planes with parachutes, they are aided by a strange new use of graphite. To prevent the formation of static electricity from friction, as the folds of silk rub together in opening, graphite is sprinkled in the pack. Besides being an excellent con- ductor, it forms a lubricant which allows the silk to slide along with a minimum of friction. The theory that caused the adoption of this precautionary measure is that static electricity might hold the silk folds together, preventing the parachute from opening in an emergency. This is only one of many unique new tasks being found for lubricants. Today the world depends upon lubrication for its life almost as truly as the aviator de- pends upon his parachute. Without proper elimination of friction, the millions of whirling wheels that supply clothing, food, and information would stop, para- lyzed. Everything from wrist watches to the giant turbines of city electric plants would cease to function. Transportation would halt, factories would lie idle, man- kind would be cut off from sources of food. While the invention of the wheel made the present machine age possible, it was the devising of proper lubricants that has made it practicable. OW does a lubricant work? Before we can answer that question, we must learn what friction is. Under a mi- croscope, the smoothest surface is seen to be covered with projections, like a cat’s tongue. When two surfaces are pressed together and moved, these projections interlock and resist movement. This re- sistance is called friction. The amount depends upon the roughness of the sur- faces and the force applied. Friction is divided into three kinds. First, solid or dry friction caused by two unlubricated surfaces rubbing together. Second, greasy friction, when partially lubricated sur- faces, coated with a thin film of grease, rub together. Third, fluid friction, when the surfaces are completely separated by the lubricant. Recent investigation has revealed that the oil film, which forces the surfaces U 4 -| Pim | he ; } ag Bee Ry ot ss pT H | | oe, a : i { ' tay a K | ' a H hei i : ‘ ii jd | i ' ae aa . id ‘4 ; re d | ; if ' a | i a. fae bY: ; i} Bae ee ‘tee a i ; a } Bi ‘ae Hl Be aa | an i : Bie Gl eae Be iI imu ' ri : ie a 4 ca F L a4 ; & 7 Bi ; ae + i 4 6-5 ele 2 -— .' “ b se 3 rs 7 - « ee Rann eam aE PRT AEE EEA RASTA ETERS LG . . i ahem bens anipaetone . n > - . eit treet <a cee = eee nn nn ge Foren ET EES SES ST RS ae ‘ —- Ane a

Page 30

AN me > po SLE RN ORT GRAM eB a ok PERS Por om ES Saree est ae i EELS AE, ENP a awnere TE eA a as Shs tn rs i ee ee a al scant ethan wate Pa eae * ey SS Sy Cone Sa MRE OES ETE. Somes noes ae Pad wok ei. 28 apart, is made up of at least three layers. One layer clings tightly to each of the surfaces and moves with it. One or more layers of free oil are between. Thus it is actually fluids, and not solids, that slide upon each other. That is why oil lubricates things and makes them slippery. HAT friction still remains, in such a situation, is “fluid friction’’—-that is, the reluctance of different layers of oil to slide past each other at different speeds. What this resistance amounts to depends upon the viscosity or “fluidity” of the oil, sometimes measured by the time a sample requires to flow through a hole of given size. Anyone who has stirred thin oil and thick grease and noted the difference in re- sistance to the motion will under- stand this. Variations in pressure have little effect upon fluid fric- tion so long as there is an oil film, no matter how thin it may be, between the two surfaces. In fact, a recent X-ray examination re- veals that a thin film of oil, only a few molecules thick, gives the most satisfac- tory lubrication for an automobile engine. A film thirty-nine billionths of an inch thick is sufficient to reduce to a minimum friction between two glass plates. All the speeding wheels in the world ride upon such a magic film of oil. HEN a machine shaft is at rest, it touches the bottom of its bearing and the oil is forced up on each side. But when the shaft begins to turn, it acts as a pump and draws the lubricant under it. Actually it rises into the air, riding on a cushion of oil. One experimenter, F. L. Fairbanks, using super-accurate instru- ments, discovered that a shaft rises be- tween .002 and .003 of an inch when it begins turning. Up to the latter half of the last cen- tury, practically all lu- bricants were made from animal fats or vegetable substances. Tallow, sperm oil, castor oil, palm oil, were all used extensively. Whale oil showed too great a tend- ency to dry out to make a good lubricant, but porpoise oil, taken from the head of this animal, and dolphin oil are still used in fine watches. In some steam engines, where the cylinders reach high temperatures, tallow is still employed as the lubricant, and in huge turbines, castor oil is often used. But these are exceptions. Petro- leum lubricants have practically supplanted all other kinds. The reason is that animal and vegetable oils tend to absorb oxygen from the air and so become rancid, thick, and gummy; when they POPULAR SCIENCE MONTHLY In cutting metal with a lathe the point of the tool must be lubri- cated to keep it cool. Adding sulphur to the oil helps it do this. decompose they form acids harmful to metal. Petroleum lubricants, which are of mineral origin, do not have these defects. Gavan TY-FIVE years ago, machinery was crude, slow-moving. The main shaft of the first gas engine, built in Ger- many by N. A. Otto, made between 150 and 250 revolutions a minute. At the time, this was declared by engineers to be the maximum that a gas engine would stand. Today, 4,000 revolutions a min- ute are common in automobile motors, and racing cars make as high as 6,000 revolutions a minute. As the speed of moving parts has in- creased, lubrication has had to become more effective. Medium priced cars are now designed to make more than seventy miles an hour, and practically every auto- mobile on the market can easily attain a Oil so heavy that it would stop a small machine must be used in these Diesel engines that drive liners. The shaft they turnis on bearings of lignum-vitae, which is self-lubricating. May, 1930 mile-a-minute rate. Average speed on American highways has increased rapidly in recent years. The result is hotter engines and hotter oil and, consequently, greater difficulty in maintaining proper lubrication. The average crank case oil temperature at thirty miles an hour is 130 degrees Fahrenheit. At sixty miles an hour, it is 190 degrees. Science is seeking improved lubricants for the new cars. O*E company, after exhaus- tive laboratory experiments, leased the Atlantic City Speed- way and sent five cars spinning around the wooden bowl day after day at top speed, eight hours a day, to make tests of their new lubricant under actual high speed conditions. It is now known that there is no sure laboratory yard- stick for measuring the suitability of a lubricant for actual service. There is some mysterious element in a good lubricant that eludes pigeonholing. Another mystery is found in sulphur cutting oils. They have the double pur- pose of lubricating and keeping cool the cutting edge of lathe tools and other ma- chine tools. It has been found that the addition of sulphur to the oil results in an amazing improvement for certain kinds of work. Where ordinary oil requires eight turns of a machine to cut steel to a certain depth, oil treated with sulphur produces the same result with one turn. Why? Nobody knows exactly. Ae. there is the seeming miracle of “deflocculated” graphite, produced by the distinguished American electro- chemist, Edward G. Acheson, who dis- covered the abrasive material known as Carborundum. The name “defloccu- lated” graphite means, literally, “with the lumps broken up;” actually it is graphite that has been reduced to par- ticles so minute that they are nearly as small as single molecules. In one test, a certain pres- sure on a bearing re- quired eight drops of the best lubricating oil a minute. When the amount was reduced to seven drops, the bearing “froze.” Yet, under identical conditions, it was sufficiently lubri- cated with one drop every ‘wo minutes of the same lubricating oil when it contained a-mi- nute quantity of the de- flocculated graphite. This addition made the oil sixteen times more effective. Whether this “miracle oil” will have handicaps that will make it impractical for wide use remains to be as- certained. Another new weapon which has been pro- duced by science in its (Continued on page 154)

Page 31

rage ars. and itly, ning rage - at rees an e is for aus- nts, eed- ling fter rs a new eed hat urd- lity ‘ice. ent des hur yur- the ma- the }an nds ires hur Im. e of ced tro- lis- as cu- ‘ith is ar- hat all res- re- the to ing der it pri- rop the oil ni- de- te. the ore his ive ike ide as- on ro- its May, 1930 POPULAR SCIENCE MONTHLY NEW IDEAS AND INVENTIONS On this and succeeding pages are described the latest achieve- ments of inventors and novel applications of scientific progress NEW FIRE ESCAPE DEVICE IS SIZE OF ALARM CLOCK FIRE protection may now be carried with one in a compact and convenient form. A small, portable “spider” life line, housed in a metal drum about the size of an alarm clock and with a body belt attached, recently was demonstrated successfully in London, England. ‘The novel fire escape may be attached to the casement of an upper story window. In making a quick escape, a person need only fasten the belt about his waist and lower himself by feeding out the steel cable line from the drum as a spider spins his thread. Safe descent is said to be assured by an automatic control on the drum which “feeds” the line out at a definite rate. The descent can be stopped and started at will by the person being lowered. GERMAN FOXES BROADCAST THEIR OWN “SOS” VALUABLE silver foxes raised on a farm in Eisenberg, Germany, report their safety or peril to their keeper, via the radio ‘‘mike.” Success in raising these creatures in captivity is greatly hampered by the attacks of dogs and wild cats, and by the temperamental disposition of the foxes, who in panic frequently kill themselves and each other. On this fox farm, which is near the famous German university of Jena, a microphone, like that used in radio broadcasting, has been installed in the fox pens and connected with an amplifier and loudspeaker in the keeper’s quarters. When all is well only the nor- mal night noises of the pack come from the loudspeaker. But if a marauding animal tries to break into the pens, or if a fight starts among the foxes, the noise, magnified by the radio apparatus, rouses the keeper, who can go immediately to the rescue. DROPPED FLARE LIGHTS AIRPORT FOR PILOTS PILoTs arriving at an airport after dark can turn on its lights from the air in a new system developed in Spain. When the pilot is over a triangle of col- ored lights on the ground, he drops a lighted flare. Within the triangle, a con- crete pillar holds a sensitive “electric eye” or photo-electric cell. The glow of a England’s portable fire escape is lowering this girl to the street 90 feet below. Top photograph: Note the lever that starts and stops descent. flare dropped within 200 feet of the pillar actuates the cell and operates an electric relay, lighting the boundary and obstruc- tion lights of the airdrome. A similar American device turns on the lights when a siren on the approaching plane is sounded (P.S.M., May ’29, p. 72). SUPERCHARGERS CUT SIZE OF DIESEL ENGINES SUPERCHARGERS, those devices which feed com- pressed air to aviation mo- tors, enabling planes to fly to extremely high altitudes, may now improve, by fifty percent or more, the power of Diesel motors used on sea, on land, or in the air. This is the claim of A. Rateau, French inventor of a pioneer type of gaso- line-motor supercharger already internationally used in aviation. Successful tests of what are said to be the first super- chargers of their kind de- signed for oil, instead of gasoline, motors have been made on a ship at Belfast, Ireland, previous tests hav- ing been made in a Copen- hagen factory. The first Diesel or oil- burning motors equipped with super- chargers were eight-cylinder, four-cycle marine engines used in pairs for passenger and cargo ships of 15,000 tons. They were designed for a maximum power of 3,300 horsepower apiece, but each de- veloped about,5,000 horsepower with the superchargers, a gain of one half. These superchargers were turbine-blowers oper- ated by the pressure of exhaust gas from the Diesel motors. Rateau declares that supercharging re- duces the size and weight of a Diesel mo- tor for a given power—an important con- sideration in aviation, where oil motors already have been tried experimentally. The higher-pressure superchargers now being developed may effect even further improvements. Rateau has designed high-pressure types for aviation gasoline motors, and in this field now introduces a remarkable new type to multiply by six- teen the atmospheric pressure at a height of 59,000 feet—should airplanes be able to fly that high. WAR GAS AIDS FIGHT ON WORMS IN CHURCH CHEMISTRY has been called to help antiquarians save the woodwork in a fifteenth-century church in Linz, Austria. Like much of the older European furniture, the ancient altar and pulpit are worm-riddled. Scores of methods to save them from further ravages have been tried in vain. As a last resort, the custodians -have tried poison gas, developed during the war. Under the direction of experts in chemical warfare, the old church was sealed, filled with the poison gas, and left alone for a week. The seals were then

Page 32

30 broken, the edifice opened and aired, and worship resumed. Whether the worms at work in the precious woodwork have perished or not cannot be determined for some time. In any event the old church probably will have to be “‘gassed” again before long, to kill any new arrivals hatched from larvae unafiected by the fumes. The results of this new experiment in disin- fecting will be awaited with interest by antiquarians who are eager to preserve architectural beauty on the continent. OVERNIGHT PHONOGRAPH FITS IN TRAVELING BAG CLOTHES, music, and a happy week- end may all be packed together in a com- bination phonograph and traveling bag lately put on the market. The phonograph is built into the lower portion of the bag as solidly as a safe in the wall of a bank. It has a spring motor turning a disk that accommodates the regulation ten-inch phonograph record. Sturdy compartments make up the traveling kit section, with a cloth- ing tray fitting over the phonograph. All one needs to do when music is desired is to remove the tray, lift the tone arm of the phonograph, and put on a record. 25,000 SLICES TO AN INCH THE most modern machines for making thin slices can pare them off only one micron, about 4/100,000ths of an inch, thick. These machines, known as “mi- crotomes,” are used in biological labora- tories for cutting fragments of speci- mens for microscopic examination. Some of these are automatic devices which will prepare from one specimen a series of sec- tions for comparison. POPULAR SCIENCE MONTHLY POISON TESTED ON INSECTS TO SHOW FATAL DOSE How much poison it takes to kill an insect is the question to which Dr. F. L. Campbell, United States Department of Agriculture entomologist, hopes “poison sandwiches” will give an answer. These, made of two leaves with poison between them, are fed to the insects in the labora- tory. The object of the investigation is to devise methods of exterminating in- sect pests without danger to beneficial insects. The ‘‘sandwiches” are used because an exact method for measuring the quan- tity of poison on a circular bit of leaf has been developed. An insect is allowed to eat the leaf until observers in the labora- tory believe the dose of poison fatal. Then the amount of remaining leaf, and hence of poison, is carefully measured, and the insect allowed forty-eight hours in which to die or recover. The first experiments were made with silkworms feeding on mulberry leaves. Dr. Campbell intends to try out his plan on many species of insects. TINY TRANSMITTER, SENT ALOFT, TELLS OF WINDS A Type of pilot balloon recently de- veloped by the United States Signal Corps is used to learn the speed and di- rection of winds when it is impossible to follow the movements of a balloon by means of a theodolite. A miniature radio transmitter, sending automatic signals and weighing less than a pound, is sent aloft attached to three hydrogen-filled balloons, which are inflated until they will rise at a speed of 200 yards a minute. Hence the height of the apparatus at any moment is known from the time elapsed since its release. At definite stations the signal direction is deter- mined each minute by means of direction- finding receivers. From these data, re- ported to a central point, the speed and direction of the air in which the balloons are drifting is worked out. United States Signal Corps engineers invented this tiny broadcaster which, carried aloft by balloons, radios reports of high altitude winds. May, 1930 TURN OF SWITCH MAKES POWERFUL ANTISEPTIC DakIn’s solution, the antiseptic adopt- ed by war hospitals and in use in every operating room, may now be made by the mere turn of a switch. An ordinary lighting current creates the antiseptic from a solution of common salt. The apparatus necessary comprises a glass bulb container for the salt and an elec- trolytic cell which was originated in the chemical engineering laboratories at Iowa State College. What it does is to rearrange the atoms of salt in solution so that sodium hypochlorite, the basis of Dakin’s solution, is formed. The value of this solution for surgeons lies in its power to split off little particles of chlor- ine, called ‘‘nascent” chlorine, when it comes in contact with animal tissue. In so doing it sterilizes a wound, stifling any germs that may be lodged there and safe- guarding the patient. Carbon electrodes are used in the spe- cial cell. The salt solution flows out of the bottom of the glass bulb between the electrodes, where the chemical trans- formation occurs. The final solution passes out through a glass tube on the side of the cell. Electricity for the proc- ess is supplied by an alternating cur- rent light line through a battery charger and is controlled by a rheostat similar to those used on radio sets. FOG IN FRONT, OF AUTO CLEARED BY EXHAUST Hor air from the exhaust is caught by a new device and sprayed in front of the car to reduce the danger of driving in fog, according to reports from London. This hot spray clears the fog to a height of about ten feet in front of the car, it is said. So rapidly is the clearing done that a speed of fifteen miles an hour through the densest fog is claimed to be possible.

Page 33

May, 1930 POPULAR SCIENCE MONTHLY British Railway Car Made of Concrete. For the first time in railroad history, concrete is used for cars. The caboose, or “‘ brake wagon,” above, was made for the London and Northeastern Railway. Its sides, floor, and roof are of concrete reénforced with steel, on a standard steel underframe, The heavy concrete is used in an effort to eliminate ballast. _ Portable Talkies Arrive Now business and education may have their own sound films. The equipment has three small units—the pro- jector, the pick-up and ampli- fer unit, and a dynamic speaker, each contained in a separate case and hung on springs to withstand the shocks of hard usage in transporta- tion. Sixteen-inch phonograph records are used. Coupled to- gether on a flexible shaft, the sixteen-millimeter film and phonograph are perfectly syn- chronized. It is designed to Tun on alternating current, though a portable converter for direct current may be ob- tained. If it is desired, silent films as well as sound films can be projected by the machine. In the photograph above a travelogue is being exhibited. * Emergency Dams Guard Holly- wood. A small army of workmen labored like beavers with tractors, steam shovels, hammers, and saws to build this series of timber check dams made necessary by a recent brush fire which swept over a large part of Griffith Park in Los Angeles, Calif., leaving the hillsides barren of protective covering. The solidly built chain of dams will hold back possible flood waters. 4. Radio Tube with Renewable Filament Mrs. Quinn, a radio research worker, has developed this novel A. C. heater type tube. The electron-pro- ducing cathode is in the form of a tiny cylinder closed at one end with the glass bulb sealed around the open end. The heating filament thus can be pulled out and a new one inserted without destroying the vacuum in the tube. Radio fans would have welcomed such a tube in the days when filaments burned out all too frequently. Filaments in modern tubes, however, outlast the electron-producing life of the cathode. Mrs. Clara Quinn, of Cleveland, Ohio. NEW IDEAS AND INVENTIONS Sak Seiae aR PEF eis Sey ar anne eudncemguninbarsenennm a epetne a ea a ae 1 so iapebeses er tres tien 2 rete erm se eter oe es a ee rene See ee es aiomanenitiies ——

Page 34

TTT SGI, CII CM Fg ae i eR Cae SATE SR I RR Le nan Pe te ee a his a « a nt tern. ane Ciena enema enters 2 enti Alin eee 32 TRACTOR-DRAWN MACHINE PLANTS SUGAR CANE Wirn the perfection of a machine for planting sugar cane, science has won another victory in the effort to conquer the Florida Everglades. The cane planter is the invention of N. C. Storey, for five years superintendent of mechanical maintenance of the Panama Canal and now mechanical engineer for The Dahlberg Sugar Cane Industries, which is converting approximately 175,000 acres of Everglades swamp land into an up-to-date sugar plantation. Running on caterpillar treads, the ma- chine simultaneously plows the swamp and sets the cane seed stalks. Drawn by a caterpillar tractor, the planter, it is said, sets twenty acres of cane in a day, the normal work of twenty men. It is equipped with two bins, which carry enough cane to plant two acres. An elevator system, driven by power from the tractor, lifts the cane from the bins to endless conveyors. These carry it to two chutes down which it slides into the furrows. One man watches the flow of cane stalks on each conveyor. The tractors draw the cane planters at speeds ranging as high as fifteen miles an hour. The plows, which turn the furrows, are directly in front of the cane chutes and can be raised or lowered, while the machine is in motion, by-power from the tractor. Twenty of these plant- ers are now at work in the Everglades. Their operation, it is claimed, is so simple that unskilled labor can be taught in a few minutes to handle them. PSYCHOLOGY MAY MAKE AUTOS RIDE EASIER AUTOMOBILE comfort is now being analyzed by testing motorists after they have finished a 150 to 400 mile run. Dr. Fred A. Moss, of George Washington University, psychologist in charge of these tests, believes that the comfort of a car should be judged by the amount of fatigue it occasions its occupants. This fatigue, he thinks, is nervous rather than muscular. As an indication of this a motorist who, after a long ride, tries to do mental gymnastics such as arithmetic finds that he is below par. Other indica- tions of nervous exhaustion are headache, sleepiness, stiffness, and dizziness. Heretofore manufacturers have spent millions in search of devices for insuring smooth driving to automobiles, most of which have proved unsatisfactory, Dr. Moss said, while recently addressing the Society of Automotive Engineers in De- troit. If comfort were to be measured by psychological methods of the _ type described, efficient ‘“‘comfort-giving”’ de- vices would be more quickly found, Dr. Moss believes. POPULAR SCIENCE MONTHLY This machine plows two furrows and plants two rows of sugar cane at the same time. Twenty of these, drawn by tractors, are doing the work of 400 men in the Everglades, now being reclaimed. STEEL “HOBBLE” SETS LIMIT TO NEW CAR’S SPEED IN ORDER to insure the engines of new cars against fast driving while en route via highway from factory to near-by dealers, a carburetor “hobble” or con- trolling device has been devised by a large automobile concern. This “orifice governor” is a thin steel plate placed be- tween the carburetor and the intake manifold, having a small opening that permits only a twenty-five-mile-per-hour gas mixture supply to be sucked into the cylinders of the motor. Any tampering with the control would be indicated by a break in a steel wire seal which is similar to those in general use by railroads to tell of unauthorized opening of freight car doors. Speeding is prevented by this sheet steel “hobble,” placed between the carburetor and the intake manifold when new car is driven. The old way. Many men are needed to dig and fill when the sugar cane is set out by hand. PREDICTS NEW ORGANS OF THOUGHT IN MAN THE world awaits the superman. And now science has predicted him. Dr. Con- stantin von Economo, of Vienna, has re- cently prophesied that man’s mind will not only improve, but will develop new organs of thought. Addressing a congress of world famous psychiatrists, or mental physicians, in New York City, he said that there are constant improvements in man’s mental capacity, and that the limit of development has not been reached. Dr. von Economo bases his prediction on studies of the cell structure of the brain carried on since 1917. He asserts that there are 107 regions in the brain, to some of which he has been able to ascribe special functions. Up to 1913 scientists had described only twenty of such areas. If this theory is sound, the age is approaching when men will com- prehend Einstein as readily as they now understand simple arithmetic. “RATTLE METER” MAKES CHEAP CARS QUIET TAKING the rattles out of small cars is made easy, it is said, by a new French invention, a “rattle meter,’ which de- tects foreign noises in a vibrating motor, transmission case, or chassis in the au- tomobile factory. Developed for the automobile firm Citroen, which makes a large part of France’s small cars, the novel device con- sists of a microphone, a radio amplifier, and an electric meter. The microphone is placed near the part of the car under test, and the electric meter’s reading gives the exact loudness of the rattle, based on an arbitrary scale, for comparison with others. Sources of objectionable rattles can then be located and removed. Hither- to the only way to check up on a car’s rattles was to give it a thorough road test. For economic reasons this practice is possible only with high-priced cars. The new rattle meter promises the small- car buyer an automobile as nearly noise- proof as more expensive models. ]

Page 35

POPULAR SCIENCE MONTHLY May, 1930 an he re yp cen ard tons, = aie — Steibaab = Chute-the-Chutes on Rollers. Children are giv- en a chance at a novel ex- and i 7 and. perience on this coaster which has ball-bearing roll- ers upon which to slide in- OF stead of a smooth surface. The rollers are so close to- gether there is no bumping, and while the trip is fast, the And inventor claims that there is Con: not much chance of injury. iS Te- will new gress ental said ts in the ‘ A Ghostlike Orches- been ha ; ‘a tra. An American radio > his engineer in Vienna has ture arranged an orchestra that He plays without musicians. th The mystery lies in the e fact that each instrument, able shown above, is a loud- 1913 speaker, connected with a vy of phonograph offstage, seen ’ h below. Cables carry the , the music to the instruments, -om- whence it issues as though now they were being played. t i Not a Bolt in This Big - u S Sign. Cleveland has this F i, electric sign, above, which is Fe 3G one hundred feet wide and ¥s \ ae hasn’t a bolt or a nut in it. i Cy rs 1S It is entirely arc welded, the Hy Lee nch first of its kind. Its structur- t ay de- al strength is such as to with- \ ui | t stand the Lake Erie gales. JEDpaR tor, At right is the cage ladder 44 au- used in changing the lamps : fH ; in the sign. It is said to make PE Fi) irm aerial electric work safer. ey Ga 3 Heid of ob at on- ifn fier, RUE e is a} i est, i the Wooden Bathing Suits. These two ‘Ene an girls are wearing bathing suits of wood. a6 i ith They are the latest novelty for use on the me at! eee \ bathing beaches. Fashioned of thin spruce ey tles they are said to be practical as costumes an 4ee 1er- also are sufficiently buoyant to encourage Bt ar’s a timid swimmer to take a plunge. So aes nad far, none of them has warped or cracked. ie ‘ice a irs. iBt NEW IDEAS AND INVENTIONS @& Y | | ay | Mm eet: | aq | i

Page 36

ee = > aede,” Rs tes eet tee eer Set a 34 NEW TYPE MICROSCOPE HAS NOVEL FEATURES UNUSUALLY powerful and versatile, a new microscope placed on the market for research workers can be adjusted by a quick change of its lenses to give any magnification from fifty to 2,250 diam- eters. Such great magnification is extraor- dinary in a portable instrument. The most powerful microscope in the world, a bulky piece of apparatus in the Bell Telephone Laboratories, New York City, magnifies objects a little more than 6,000 diameters. In the new instrument the stage, on which objects are placed for examina- tion, is on the side nearest the user, giving easy access to slides of specimens. Twin eyepieces avoid evestrain or squinting by making it possible to use both eyes at once. These slant toward the operator so that he may sit comfortably relaxed. Microscopic photographs may be made by laying the instrument on its back in a horizontal position, the design of the frame insuring steadiness. MAN-MADE PLANT YIELDS STOCK FOOD AND PAPER A NEW plant, “made” in England, after many years experiment by Leonard Browning, yields a valuable raw material which may supplant jute, hemp, and sisal fibers. Experts consider its wood excel- lent for fine grade paper, and its seed highly nutritive as a food for cattle. The plant is known as brotex. It can be readily cultivated, either by direct sowing or by transplanting from nurseries, and its growth is very rapid. The yield is sixty tons to the acre, pro- ducing slightly more than two tons of the air-dried, commercial fiber. This is valued at $160 a ton. GAGE ON SQUARE SHOWS CASTING RECESS DEPTH WITH a new depth gage attachment, the combination square of the garage man or machinist takes on new usefulness. The attachment aids in measuring in- This gage, with graduated blades, is clamped to a square and used to measure casting recesses. POPULAR SCIENCE MONTHLY A new type microscope with magnification up to 2,250 diameters has the stage next to the opera- tor and tilted eyepieces. stantly the depth of a recess in a casting of any sort, where its width would make the measure- ment difficult with any other type of instrument. While the square is held on the upper sur- face of the casting, the gage plumbs the bottom of the recess. It can also be used to measure the depth of holes, in order to determine the proper length of a bolt or plunger. Clamped to the blade of the T-square, the attachment uses a set of measuring blades graduated in various ways. A thin rod is also provided for measuring small holes. WATER BLISTER FLUID CURES DRUG ADDICTS From Egypt, rapidly becoming the medical center of the Orient, comes a re- port of the accidental discovery that injections of fluid from a water blister, such as is raised by mustard plaster, may be used to cure ‘the drug habit. Word of this strange cure reached the American Medical Association from the European Hospital at Alexandria, where Dr. Modinos, chief attending physician, had been injecting blister fluid into the body of an Arab afflicted with rheuma- tism, a common treatment for this disease. But the Arab also happened to be a cocaine addict. To the physician’s astonishment, the Arab completely lost his desire for cocaine. Acting on a hunch, Dr. Modinos tried the blister fluid on a morphine addict. Again the striking result, with a com- plete cure after two injections. With such unique evidence to support them, the officials of the European Hospital intend to test the treatment on all drug addicts that enter their halls. May, 1930 ARTIFICIAL SNOWFLAKES * MADE WITH LIQUID AIR: ARTIFICIAL snowflakes have been pros duced for the first time in Los Angeles, Calif., a city that almost never sees natural snow. Professor John Mead Adams, of the University of California, after ten years of research has perfected an apparatus for creating snow crystals from liquid air. Immensely colder than the water vapor from which flakes are formed in the sky, liquid air exists at temperatures colder than 190 degrees below zero. In the Adams _ process, liquid air evaporates to form a stream of cold dry gas that meets in a cold chamber a counter stream of cold moist air only a degree or two above the freezing point of water. Instantly the super-cold gas turns the moist ordinary air into thousands of snow crystals. The flakes so pro- duced, however, are so small that they must be looked at under a micro- scope. Some of them grow larger by devouring, like cannibals, their smaller fel- lows. All previous attempts to make snow by freezing fog or by cooling water sprays have failed. The flakes, all of which are six-sided, are formed according to the laws of water crystalliza- tion; and their growth is believed to be due to con- densation on an initial crystal nucleus. The artificial flakes may be built up into numerous and varied patterns, ranging all the way from cuff buttons to the intricate designs of lace. DOCTORS ADVISE WOMEN TO KEEP SHORT DRESSES PHYSICIANS deplore the long skirt “re- lapse” of women. They would stop, if they could, the change of fashion which seems to be bringing back the hampering dresses. Health, they claim, is outraged by the long, sweeping skirt, which stifles activity. If there is a return to the “wasp waist,” demanding corsets and form- fitted dresses, it will mean, they say, a return of displaced organs. Greater health and endurance have come to women as the result of unrestricted physical activity. Dr. W. G. Morgan, president-elect of the American Medical Association, em- phatically declares: ‘Since the more sane type of clothing worn by women at the present time, there has been a striking de- crease in physical defects. Lung capacity has been increased and lung activity be- come more nearly normal in the average young woman. There has been a marked improvement in circulation with a cor- responding improvement in the color and texture of the skin, with a lessening of the necessity of-the use of rouge and powder. Let women guard the greater freedom of mind and spirit which has been given to them by their lately acquired physical freedom.”

Page 37

con- leus. into g all icate p, if hich ring aged tifles vasp orm- y, a ater cted t of em- sane the r de- city be- rage rked cor- and the der. Jom iven sical May, 1930 Radio Squeal Is Music Noises from oscillating radio tubes once more are turned into music, this time in an electric organ devised by R. C. Hitchcock, above, of the Westinghouse research staff. The instrument is played by pressing the keys of a three-octave pianolike keyboard. The volume is controlled by operating a foot pedal. The organ is particularly adapted to radio broad- casting, as the impulses produced are electrical. Tail Lamps for Walkers In Germany pedestrians are now wearing these safety belts, which have a red reflector attached to the back. A car’s headlight, it is said, will light up these reflectors from seventy yards away, thus reducing the danger of accidents on the highways at night. Even if the driver mis- takes the pedestrian for a motor cycle or automo- bile truck, the walker stands an even chance. NEW IDEAS AND POPULAR SCIENCE MONTHLY No Ribs, but Rain Proof. This fold- ing umbrella, made of waterproof ma- terial, fits the pocket or can be carried under the arm, ready for a sudden down- pour. Folds on the inside serve as handles, Air Pads These Boxing Gloves. Pneumatic boxing gloves are being used in place of those padded with hair by Joseph Lapidus, left, director of the Harry E. Burroughs News- boy Foundation Gymnasium, Boston. They are inflated with a bicycle pump and it is claimed that, while the punch remains, it “‘spreads” on land- ° ‘ing, preventéag cutting of the skin. ke fom @ i Like Riding a Horse. This gal- loping tricycle is driven by weight ef the rider. With his feet braced against the pedals, he raises and low- ers himself as in horseback riding. Resultant up and down movement of the seat turns a sprocket wheel. INVENTIONS aacaenenge oar te nap enya — I TE II A TEE AI LO NE CD EE A EN EET BEE ET a are :

Page 38

36 > slg tex as 2 7 Fg. iy - 7% AOA Sewer gS | g tf, ? 1M, + 6S Si ¢ ¥ See Rg i fr OE ° - of ay CARDS OF ALUMINUM LOOK LIKE PAPER HERE are the new playing cards of aluminum, recently described in POPULAR SctieNCcE Montuiy (Mar. 730, p. 66). They look exactly like ordinary cards, can be handled just as easily, and will not bend or tear. Also they can be washed if they become sticky or soiled after much use. The cards’ weight makes them difficult to blow away, so they are particularly suit- able for the summer cottage or for camp- ing or boating trips. PORTABLE RADIO SOUNDS HIGH VOLTAGE WARNING Less easily ignored than a ““Danger— High Voltage” sign, a new device, de- veloped in France for electrical workers, howls a danger signal when a line carry- ing high-voltage alternating current is approached. The compact apparatus, readily portable to be.carried on the per- son, resembles a miniature radio set, loud- speaker and all. Its principle of operation is the same as causes interference in a home radio re- ceiver frem a near-by electric power line. The electric field or influence around a high-voltage carrier actuates a small radio circuit with a vacuum tube and batteries inside the device. It sounds a warning through a small but exceedingly sensitive loudspeaker when a push but- ton contact is made. It may be used to warn of proximity to transmission lines carrying electricity at from 1,000 to 100,000 volts. GROOVED SCREW DRIVER WILL NOT SKID THE harder a new “nonskid”’ screw driver is twisted, it is claimed, the tighter it grips the slot of the screw. Its secret lies in a series of V-shaped ribs cut in the tip of the blade. This feature, the manu- facturers say, makes it possible to turn even battered and rusty screws. Slipping when driving greasy or oily screws is also eliminated. Damage to the screw slots or to the finish of woodwork by a slipping screw driver is thus avoided, it is claimed. POPULAR SCIENCE MONTHLY NONFRAGILE COPPER IS SOUGHT AS CONDUCTOR INVENTORS, seeking fortunes in their search for a process of hardening copper, would better turn their energy to other problems. One of these is to find a way to take the fragility out of copper wire and still leave it a good conductor of electric current, declares W. H. Bassett, who is technical supervisor of a Water- bury, Conn., brass company. Copper is fragile because of minute quantities of copper oxide in the metal, he says. One of the reasons for alloying copper with other metals, such as zinc, is to remove this oxide. This metal or phosphorus is used to treat practically all the copper made into commercial tubing. But such treatment increases the electri- cal resistance of the wire and makes it less useful as a conductor. Copper alloys of great usefulness have been discovered recently, according to Bassett. Because of its resistance to cor- rosion, ambrac, one of these new copper- nickel alloys, is employed in making the condenser tubes used in steam power plants. Alloys of copper with silicon can be welded as easily as steel and, incident- ally, yield a copper that has been hard- ened cheaply and effectively. One superstition that has persisted for years is that the art of hardening copper is a lost one. This is not true (P.S.M., Dec. ’27, p. 52); in fact, modern hard- ening methods are more effective than those of the ancients. A one-inch bar of good commercial copper, without anneal- ing, can be drawn to a wire only two thousandths of an inch thick. STARS THAT BEAT WOULD BURST IF THEY ROTATED Stars, like many human beings, can- not do two things at the same time. Astronomers have long known that some stars turn on their axes, while others pulsate like gigantic hearts. But the same star cannot do both. So Dr. Ross Gunn, of the Naval Research Laboratory in Washington, has reported to the Amer- ican Physical Society. This helps to explain the puzzle of the Cepheid variable stars, which are be- lieved to pulsate. But if they were also rotating, the strain of centrifugal force probably would burst them apart. . The V-shaped ribs on the tip of this screw driver give a grip that stops skidding on screw head. May, 1930 NET, HOOKED TO CAR TOP, HOLDS MANY ARTICLES Wuat the closet does for the house a new suspension net does for the auto- mobile. Attached by metal hooks to the bows supporting the top of the car, it carries papers, clothes, packages, blank- ets, maps, and other small articles. Fur- thermore, it carries them in a neat, safe, and compact position. It keeps articles in plain sight where they can always be found. There is no interference with head- room, its makers claim. The hooks at- taching the net to the ceiling may be quickly screwed in. Thus seats need no longer be cluttered with miscellaneous packages, often misplaced or lost. The net, it is said, fits every make of car on the market. INSULATOR AND CONDUCTOR IN ONE SUBSTANCE Most substances are classified as “‘in- sulators”’ or “conductors’’ of electricity,, depending on whether they confine or transmit it, but a new substance, known as “thyrite,”’ is both. This novel material, according to K. B. McEachron, General Electric Company engineer, is an ideal safeguard for electric transmission lines. Ordinarily it acts as an insulator and prevents current from leaking. When the line is struck by lightning, however, thyrite becomes a conductor and allows the dangerous current to escape harm- lessly to the ground. Thyrite looks like porcelain and has the color of black slate. It is molded by a complicated process from a number of materials, including silicon carbide, a commonly-used abrasive called by vari- ous trade names. When adapted for use as a line protector the tips of a piece of thyrite are sprayed with metal and form the contacts. ° Because of its peculiar constitution, it ‘behaves much like the common lightning arrester that protects radio outfits, in which a small gap bars discharges of low voltage but allows high ones to pass. In thyrite this seems to be a structural property of the material itself. It violates the familiar.electrical law that doubling the voltage applied to a conductor in- creases the current to twice the amount; in thyrite, this increases the current a fraction more than twelve times.

Page 39

ree eee Deeg pe wir eras te Faire eee tineesan May, 1930 POPULAR SCIENCE MONTHLY ian inna Dacca —“ How Fast Is It Safe to Come Up? Inacompressed air chamber at the Washington Navy Yard, sailors learn how rapidly they would be able to ascend ‘ee from a sunken submarine. Too rapid travel from deep to shallow water would New Brake Tester. Four heavy flywheels in this cause “bends.” The men are wearing Momsen “lungs,” new rescue device. device measure the brakes’ holding power. Spun by the car’s wheels, they simulate the momentum of a moving auto. When brakes are applied, record- ers show how long it takes to stop the flywheels. Vacuum Printing Machine, A Brooklyn, N.Y., air map firm uses this device in making large prints. With negative and paper in place ‘ a sini _—aee . under glass, an air pump creates a Eicvecer-com Proving a Singer Can Sing. vacuum, forcing perfect contact. A ee The tonoscope, developed at the Uni- rubber blanket keeps the pressure ssesvee ° j : j ’ 2 . “y : : versity of Iowa, measures a singer’s uniform. Note gage at lower right. seeeee pitch and detects the slightest off- key note. Rows of holes are arranged Ratet Teale Gust ‘ = - - ot — = above —_ = obot Traffic Guide. This de- ~ : x : i and illuminat rom inside. e vice, worked by levers buried in the ; row of holes that correspond to the roadway, “feels” approaching cars pone ~ rer tone rendered appear to stand still. and flashes them a “go” signal if : - = thal traffic is clear. It takes the place of a traffic cop and shows almost. hu- man judgment in its operations. NEW IDEAS AND INVENTIONS tp cieaepion a

Page 40

en eae in fines OS ELLE LS SLC TLER NE : 0 ORE OE ALE LT NS 38 WINGED OUTBOARD MOTOR CRAFT SETS NEW RECORD AN ENORMOUS dragon fly with a human head has been seen recently flitting about the waterways of Alameda, Calif. It is the “waterplane,” a new type craft able to make sixty-five miles an hour with an outboard racing motor. Two wide, flat- bottomed pontoons joined in tandem by sturdy struts make up the “chassis,” from which typical airplane wings spread laterally. The outboard motor is placed on the rear pontoon. The wings are said to contribute to the high speed of the craft. A genuine airplane thrill is claimed. VERTICAL HEADLIGHT ON ENGINE TO WARN AUTOS Mororists who see, at a grade cross- ing, a locomotive pass with its headlight pointing up in the air need not be surprised. The Pennsylvania Railroad plans to test the suggestion that a per- pendicular beam of light may be an ef- fective warning to motorists on highways that cross the tracks. The plan is to equip a passenger loco- motive with a vertical headlight and run it over Ohio lines. For 700 or 800 feet the beam of light will ascend toward the clouds. Experts believe that this beam will be visible to approaching automobile drivers at a much greater distance than a horizontal shaft of light. GAS TANK LOCKING CAP WILL THWART THIEVES A DEVICE to thwart gasoline thieves has recently been invented. It is a new type of locking cap for gas tanks that can be opened only by its own key. The cap was originated as a means of preventing illegal gas leakage of all kinds. In case a car is stolen, the locked cap would prevent refilling of the gas tank and hence the car could be run only as far as the gas already in the tank would carry it. The novel cap may be procured for both automobiles and trucks. POPULAR SCIENCE MONTHLY NEW TYPE AUTO TRAILER HAS ONLY ONE WHEEL AN aAvuTO trailer which has only one wheel appeared recently on the market. This versatile wheel adapts itself to any situation. The body of the trailer is at- tached rigidly to the automobile in the horizontal plane, remaining fixed no mat- ter which way the car goes. It is claimed that the new trailer is easier to maneuver than the familiar two-wheelers. Tourists, campers, and merchants may all find it in designs suited to their needs. TREATED WITH HEALTH RAYS, ICE CREAM CURES RICKETS EvEN ice cream is now treated with the rays of artificial sunshine to make it more healthful. When samples of about one ounce each were given from fifteen seconds’ to ten minutes’ exposure to New type cap for gas tank of a car locks on and can be opened only with the key, thus preventing theft. May, 1930 ultra-violet or health rays emitted by a mercury vapor lamp, F. C. Button, of Morehead, Ky., and two associates found, recently, that they made effective doses to cure rats of rickets, a bone disease that also affects humans. RUSSIA’S GIANT DYNAMOS BIGGEST IN THE WORLD Tue first hundred-thousand-horse- power dynamos ever designed for hydro- electric power are under construction for a Russian power plant on the Dnieper River, according to a recent announce- ment of the General Electric Company. These titans will be near- ly half again as large as the huge machines at Niagara Falls, N. Y., for many years the biggest of their kind in the world, and will far outclass in individual size, though not in number, the great turbines of the Cono- wingo, Md., plant de- scribed on page 49 of this issue. Four of the turbine- and-dynamo sets are be- ing built. The power plant is to be erected at Kichkas, in the Ukraine, where, under the direction of Ameri- can engineers, the last of the turbines is to be installed in 1932. Each generator will be forty-two feet in diameter at its widest part and will weigh 1,760,000 pounds. The steel shafts which couple each dynamo to its water wheel turbine are thirty-six feet long. 2,000,000 PERSONS’ THOUGHTS EQUAL ONE LAMP POWER Ir Two million persons were to think of the same thing at the same time, they would generate, collectively, enough elec- trical voltage to light one ordinary in- candescent lamp. This is the conclusion of Dr. Edmund Jacobson, of the University of Chicago, who says he has shown, after two years of experimentation, that a measurable electric effect accompanies human thought. In his experiments he used a “string gavanometer,” that can measure a millionth of a volt of electricity. Subjects in Dr. Jacobson’s laboratory had electric contacts attached to the right biceps or pulling muscle of the arm, the other end of the wires being connected to the galvanometer.* At a signal, a sub- ject would try to imagine that he was flexing his arm. A quartz string in the recording instrument vibrated in response to the electric impulse this mental effort generated. When the subject stopped thinking, thestring wasstill. According to Dr. Jacobson, the thought of flexing the muscle was-what induced the electric dis- charge. He succeeded in measuring its value and even in throwing the image of the vibrating string on a screen so that a subject could “see himself think.”

Page 41

1, of und, loses that IS D orse- ‘dro- n for leper ince- neral ny. 1ear- re as s at , for gest orld, ss in ough treat »no- - de- this yine- . be- wer ‘ted the nder neri- st of 932. feet will 1afts ater iTS hink they elec- ’ in- und ago, ears able man ada sure tory ight the cted sub- was the onse ffort yped 1g to the dis- . its re of at a May, 1930 It’s the Nearest Thing to Flying Like a Bird Featherweight soaring ships spiral in: the blue sky as they ride the wind without a sound. American glider pilots to try for a world endurance record. POPULAR SCIENCE MONTHLY By EDWIN W. TEALE Colonel Charles A. Lindbergh flew his new Lockheed monoplane on a peculiar quest. A few weeks ago, with W. Hawley Bowlus, America’s foremost glider pilot, he established a mountain camp at Lebec, Calif., to learn the technique of soaring. Then he began flying over the headlands and hills of the seacoast looking for the best spot for an attempt to break the world’s endurance record for motorless planes, now held in Germany by Hermann Dinort at fourteen hours and forty-three minutes. Meanwhile, members of the POPULAR ScIENCE MontHLy-New York University expedition are seeking a suitable location near New York City for the first National Soaring and Gliding Meet to be held late this summer. Travis Hoke, Editor of POPULAR SCIENCE MONTHLY, has been asked by the National Glider Association to head thissearch. In a few weeks, another motorless plane contest will be held at Bay- side, Long Island, N. Y. Soaring and gtiding stars from all over the country will compete. At this contest, Lieut. Ralph Barnaby will repeat his spec- tacular feat of cutting loose from the dirigible Los Angeles and spiraling to earth, using the glider he piloted in his recent successful tests at Lakehurst, N. J. Capt. Frank Hawks is also expected to complete his proposed double transcontinental glider flight, towed behind an airplane, in sufficient time to take part in the Bayside contest. A LONG the California coast, recently, Will the members of nearly forty gliding clubs affiliated with the National Glider Associa- tion, scattered from coast to coast, making exciting hops down hill- sides in primary training gliders and hoping to pilot the delicate, featherweight soaring ships that ride the wind for hours, interest in this type of craft is increasing daily. Soaring is the nearest approach to bird flight man has yet . - Mrs. Lindbergh taking off in the flight which won her a first-class license at San Diego, Calif. achieved. Under ideal conditions, it means spiraling in the blue sky, high above valleys, woods, and villages—soar- ing without a sound, except the rustle of wind along the wings, mile after mile in hawklike flight. The longest cross-country journey ever accomplished in a motorless machine, es ay. = ©. ew Navy Lieutenant Ralph Barnaby has just cut loose from the Los Angeles at 3,000 feet. In 12 minutes he glided to Lakehurst port. however, was made under far from ideal conditions. Robert Kronfeld’s 102-mile flight over central Germany, last sum- mer, began with a nerve-tingling race with a thunderstorm. As he was launched from Mount Wasserkuppe, in the Rhoen Mountains, raii’ began to patter on the wings and fuselage of his machine, and the force of the wind increased. “There is thunder on all sides,’ Kronfeld writes in his story of the flight. ‘‘Fantasti- cally built clouds crowd together behind me. They come nearer and nearer. The altimeter climbs without stopping. The higher I get, the quieter it seems. I can see over the stormy clouds on both sides. I already can see that it extends from west to east and way out north. I spot the town of Berka far down below me. I am already 4,500 feet above the starting point. Small white clouds, like pigeons, arise below me. Wrecked clouds are whirling around me. They are getting denser and denser. A glance to my right and left shows me there is no longer a chance to escape. “IT am trying hard to keep straight ahead eastward, but it seems impossible. The compass runs around in a circle. A howling noise is commencing around me. My speedometer starts trembling, jumps to fifty, sixty, and seventy miles an hour. By pulling up the machine, I try to lower the speed. I have a feeling I am standing with my feet against the sky. I am getting pushed down by some irresistible pressure against my quel - bam - . my - Sees ee Se Se

Page 42

_ F a 7 a . - Ce ae ae ELE CEE A meuare tied Bos sewn ans neem, xapemee Stake, SIRE. ere? 40 seat. I start thinking of my para- chute. “Suddenly it becomes very quiet. My vision, as in a fever dream, is first very faint, then more distinct. Fields and gardens are circling around me. The town of Eisenach lies below me and I keep right on. My rain-soaked hair starts drying as well as my shirt. My teeth are chattering. Fields and towns pass by. My watch shows seven o’clock in the evening. The moisture of a hot summer day lies above the country. Time passes and it begins to get dark. Wide empty fields are stretch- ing below me. The clouds in front of me are vanishing. I am coming down. There are woods below me, far away a town, a railroad, quite a large place just suitable for landing. A few curves and the ship slips through the grass. The flight is ended.” ANOTHER amazing record was set not 4 & long ago by this same pilot when he climbed to an altitude of more than 9,000 feet in his engineless ship. Other pilots have flown more than 300 miles, circling about, and have landed at predetermined spots. One flyer carried a passenger to a height of 4,000 feet and flew twenty-four POPULAR SCIENCE MONTHLY At a Rhoen soaring meet a big gallery of spectators watch the light sailplanes hurled into the air by long rubber cables. Max Kegel, famous “‘cloud flyer” of Germany, in the cockpit of his glider. Note the air speed indicator in front of him. miles across country with him. Over the sand dunes that border the Baltic Sea in northeastern Germany, the other day, a sailplane pilot jockeyed his craft for several hours while a passenger read to him from a book. Twice, motorless planes have flown more than fourteen hours. The first time this was accomplished the late Ferdinand Schulz, the ace of soaring men, was at the controls. Schulz was killed last summer stunting in a motored This unusual sailplane was guided by R. Kronfeld for a hundred and two miles of continuous flight over mountains, villages, and forests of Germany, in his effort to set a new record. May, 1930 machine and not, as was first reported, in a glider crash. The second man to pass the fourteen-hour mark was Hermann Dinort. A few months ago, he soared over the Baltic dunes all night and weathered a violent storm to advance Schulz’s endurance record more than thirty minutes. At first the idea of flying without an engine seems absurd. But it isn’t. The air is filled with invisible rising and descending currents. For instance, when a_ wind strikes the side of a hill, it is deflected upward and forms a strong lifting column of air. As a general rule, this upcurrent reaches to a height twice that of the object which deflects it. When a light sailplane enters such an updraft, it is lifted faster than it descends. Throughout its flight, a soaring plane is always gliding down- ward with relation to the air. It does not reach the ground because the pilot steers it from one rising current to another. The altitude lost between up- drafts is regained in pass- ing through them. In other words, the rising air current carries the soaring plane upward faster than it glides down. The per- fect streamlining and the light plywood construction of the soaring craft allow them to advance as much as twenty feet for every foot they go down. This drifting descent permits them to soar long distances without losing much altitude and to pass slowly. through rising air columns. ones of the lightest of these thistle- \J down craft have strong cantilever wings that weigh only five ounces for every square foot of supporting surface. When W. Hawley Bowlus set a new American endurance record by circling through the dark over Point Loma, Calif., for nine hours and five minutes. guiding his flight by the flashing beacon of a lighthouse, he used a machine that weighed fifteen pounds less than he did. Bowlus weighs 190 pounds. The sixty- foot man-made gull, which he constructed in the factory where Lindbergh’s famous Spirit of St. Louis was built, weighs only 175 pounds. An experience of Orville Wright, the first man to fly an airplane, illustrates the almost unbelievable power which rising air currents exert in reference to aircraft. In 1910 he was descending from an al- titude of about 1,500 feet near Mont- gomery, Ala., when he. suddenly discov- ered he was unable to come down any further. “‘My motor was throttled to the limit,”’ he writes, “and the machine was pointed down as steeply as I felt it safe to point it. I remained at this height for a period of five minutes without any appreciable descent. Suddenly the ma- chine began to descend and was on the ground in less than a minute.” His explanation is that he had run into a huge column of rising air of greater diameter than the 500-foot (Continued on page 152)

Page 43

930 ted, Dass ann red and ince han an n’t. ible nts. ‘ind t is Sa As ent hat it. ters ster out ane vn- the the lot ing “he up- LSS- air ing an er- the to ity go nt ng de air ad us ly he ne 1g 1. t- v- Ly

May, 1930 POPULAR SCIENCE MONTHLY 41 Lindbergh Goes Gliding Three Pages of Pictures Tell the Story of the Lone Eagle’s Life at Lebec, Calif., Where He Mastered the Art of Gliding Colonel Lindbergh, right, looking over the soaring country near Lebec, Calif., f with W. Hawley Bowlus, $3 <i America’s foremost flyer ; <5) of motorless airplanes. a et a On one of his first flights Lindbergh soared fifteen miles over the Tehachapi Mts., where the American ace mastered the technique of the new sport of motorless flying.

t —— ‘ Ae ’ - fee Above, Lindbergh is working on a wing of the glider that cracked during an experimental flight. In circle, the Colonel is helping Bowlus hook up the glider controls. At right, after the flying is over, the Lebec campers, with Mrs. Lindbergh at the table, center, and her famous husband, left, are resting.

Page 44

POPULAR SCIENCE MONTHLY May, 1930 Dragging the sailplane behind a car to the starting point, where runners stretched the heavy rubber cabie that shot the light plane out into rising air currents at the top of a hill. + bee =e ee. e ec ARSE A A A A Rt ae | : P ra Dr. Alexander Breese, Government weather : = Above, Mrs. Lindbergh is an interested observer expert, installing the anemometer and vane Ss — in ie of the experimental glider flights near Lebec. At which showed Lindbergh direction and force - - left the great flyer is hard at work soldering a wire in of the wind so he could plot the best course. ; assembling the engineless sailplane which he flew. es 8 Above, attaching shock cord to nose of Lindbergh’s glider just before be took off. Left, Lindbergh and Bowlus at work assembling the sai!p!ane.

Page 45

May, 1930 POPULAR SCIENCE MONTHLY , é ; s ‘ y 3 ad This remarkable photograph, one of the most beautiful ever made of a glider in soaring flight, shows Colonel Lindbergh maneuvering a motorless airplane above the foothills of the Tehachapi Mountains, Calif. On the rising currents of air thrown up by hillsides such as these American glider pilots hope to set a new world’s endurance record of more than fifteen hours. Lindbergh seated in the sailplane waiting for the take-off of-an early flight in which he sailed fifteen miles, circled a, mountain lake several times, and stayed aloft twenty-one minutes, before he swooped down for a gentle landing in a field in one of the valleys below. When any repairs were necessary on the gliders, Lindbergh was always on hand to help make them. Here he is seen, near the center, assisting in put- ting a new wing on the soaring ship which was used in the gliding experiments at the Lebec camp. The machine’s main wing measures sixty feet across. ae ict ai

Page 46

its eT. bo Pas SRE TT Se eS eee as ep SO ee a Sa sera esac scents Sette eee ms wones _— Te Aiea a 44 POPULAR SCIENCE MONTHLY May, 1930 If the Ocean’s Floor Were Dry i — THOUGHT 1 To BE | y THE FABLED LOST By CONTINENT OF “ -VMEWFOL INP. ANP ~~ METHOULET DEEP: (18,600 FT.) LIBBEY DEEP? > LIN __(2000FT) a rh wes CONTINENTAL NORTH AMERICA SIGSBEE DEEP (19,800 FT.) NEW ORLEANS GULF OF m* aS SLANDPS a MEXICO pees, BAHAMA AAU ISLANDS (fa reer AFRICA ho (19.200 FT.) CHUN DEEP (19,S00FT). DEEPEST HOLE. IN ATLANTIC (27,972 FT) " NARES DEEP (20,400FT) | ae ae ISKNOWNTOBE THE — | | a p DREEDING PLACE OF EELS } va I PryORT DEEP (19.200 FT.) PORTO TR MA CARIBBEAN SFA RICO é : (16 800 FT.) : E (18,000 FT.) SOUTH AMERICA ASIA-MI EVEREST (29,141 FT.) ed ig ie el te AGREE ce. $.AMERICA-MT. ACONCAGUA, . sim Frat (22.834 FT) CAPE COD \ - } \n AERCAMT MCKINLEY = DOTTED, LINE INDICATES ROUTE OF SHIP - a 90 FT) a a Se a ca os Oe oe ee AZORES / \* RFRICA-KIBO PEAK | oa i | (19,710 FT.) ! sia tes cs a. i nRwn i EUROPE~MONT EL BRUS, | PLAN VIEW SHOWING COURSE OF U.S.S. STEWART ON OdEAN- ~SOUNDING CRUISE “GIBRALTAR 2 ae -5 CAUCASUS (18,465 FT.)) ——————— sot a arena ae neem i } CUTAWAY VIEW OF OCEAN FLOOR, IN PROFILE. uh AS DETERMINED BY USS. STEWART, JUNE 1922 HIGHEST Pic SUNTAINS| * | (VERTICAL SCALE GREATLY OF THE CONTINENTS | | 4 6.000 FT. BELOW SEA LEVEL MAGNIFIED) | ie a. | COMPARED WITH AUSTRALIA — ~ {OCEAN DEPTHS MT KOSCIUSKO a (7,328 — FT.) =. yl Sete ERE SEA L x 2 AVERA PLEVATION OF\ = LAND AREAS ON 12,000 FT BELOW SEA LEVEL 18,000 FT. BELOW SEA LEVEL Drawn especially for PopuLar ScieENcE Montana ty by B. G. Seielstad EARTH(2,800FT) 7 OUNDINGS of the Mindanao Deep in the Pacific Ocean, near the 0 Se Philippines, proved recently that the sea’s greatest depth is OF OCEAN 35,410 feet, which is just short of seven miles. In such a hole (12,500 FT) \ the highest peak would be lost more than a mile below the waves. \ From the top of Mount Everest to the bottom of Mindanao Deep is a vertical drop of a little over twelve miles. Accurate and rapid measurement of these great depths was made possible by the ‘“‘sonic depth finder,” a device, developed during the World War, that uses the echo from the ocean’s floor in making its soundings. On this page is a suggestion of what the bed of the North Atlantic would look like if the water were drained away. A great pit, 27,972 feet deep, would GREATEST Wonctte r IN CARIBBEAN AS FAR cA be found near Porto Rico, marking the spot of the Atlantic’s greatest depth. A plateau would be found near the Azores and a vast table- land would appear near Newfoundland. A typical cross section of the ocean is shown above. This was made by the United States warship Stewart in 1922, and in spite of enormous depressions, it proves that great stretches of the ocean’s floor are comparatively level. Y os GREATEST DEPTH IN / io 76 FL) [AN SEA — SPOT IN i a OCEAN ahd 1OFT.)

Page 47

| ee May, 1930 POPULAR MONTHLY SCIENCE 45 PROGRESS AND DISCOVERY Important achievements in engineering, exploration, and dis- covery, and the latest news of the world’s progress in science Rubbish from Streets Paves German Cities NATURE, the supreme economist in conserving waste matter and reconverting it by chemistry into new uses, has been well patterned by a ‘‘reclamation” plant on the outskirts of -Berlin, Germany, where untold tons of rubbish salvaged from the city streets are transformed into building materials. The industry liter- ally rescues from the scrap heap millions of dollars each year. The refuse is burned in huge ovens, the ashes forming the basis for bricks, pipes, and other construction materials. In 1929 the plant produced 3,333,333 paving blocks, used for the pav- ing of streets throughout Germany. Found —‘‘87,”’ One of Two Missing Elements **ELEMENT No. 87,”’ one of the two long- missing items in the chemist’s catalogue of ninety-two fundamental substances of which all things on earth are made, is re- ported found at last. Dr. Fred Allison and Prof. E. J. Murphy, of the Alabama Poly- technic Institute, have discovered it in samples of ore from Maineand have named it “ekacaesium,” although as yet they have not succeeded in isolating it from the ore. Their discovery, if confirmed, leaves only element number eighty-five to be hunted by the chemical explorer. The search for missing elements has been romantic. As early as 1870 the Russian chemist Mendeleeff found that when the sixty-three elements then known were arranged in a nine-column table in the order of their atomic weight, whole rows of them were strikingly alike in chemical and physical behavior. Blank spaces appeared, however—both in this in- genious table and in a later scheme of ar- ranging elements according to the number of free-spinning electrons they possessed —from hydrogen with only one elec- Here are some of the finished products salvaged from German refuse: paving bricks, conduits, and wall partitions. tron to the uranium atom with ninety- two. It was but logical to conclude that there were in all ninety-two elements —that the blank spaces represented un- known elements and that from the tables their properties could be predicted before they were discovered. Confirmation of this theory came swiftly as one after another the “missing” ele- ments were discovered. In every case their properties proved remarkably like those predicted. The latest, ekacaesium, fits into the list between radium and ra- don (radium emanation) and is the sixth heaviest of all atoms. Now only one is missing. Chemists are reasonably sure that the complete list stops at ninety-two and that nothing heavier or bulkier than the uranium atom can exist on earth; though more complex elements may possibly exist in the sun, stars, and elsewhere in the universe. Aluminum Best Reflector for ‘Sunshine’ Lamps Mrrrors of aluminum, widely used as reflectors in artificial sunshine lamps, re- ceived a clean bill of health in a recent in- vestigation by the United States Bureau In oval: Unloading a truckload of rubbish at the Elberfeld-Barmen plant. The huge ovens above re- duce it to ashes from which build- ing materials that are worth mil- lions of dollars are manufactured. of Standards. It was one of the first surveys to determine the ability of various polished metals to reflect the benefi- cial “ultra-violet” rays given off by such lamps. Aluminum reflectors, the experimenters found, reradi- ated nearly fifty percent of the ultra-violet rays of me- dium wave length that fell upon them. This was considered a high figure. An- other metal tested, rhodium, reflected from thirty to forty-five percent of the rays, depending on their wave length. Tin was classed as having a “‘fairly high” reflecting power but, tarnishing quickly, it loses its value as a reflector. In pre- vious tests chromium as a metal reflector of ultra-violet light received a high rating, comparing favorably with aluminum. Auto “Signals” Bother Radio Stations THAT motor cars on the highway may interfere with a near-by radio receiving station was revealed recently by Ralph Brown, of the research department of the Bell Telephone Laboratories. The trouble, he told the American Institute of Electri- cal Engineers, was that each car’s ignition system, with its spark coil, was a minia- ture broadcasting station, and its “sig- nals” came in nearly as strongly as weak short-wave radio signals from Europe. For that reason the transatlantic receiv- ing station at Netcong, N. J., he explained, was purposely erected at a distance from automobile highways. Aa eet Lg SR SERRE A Se EE ee Ln a map gt ner po ewcnaeslt en . > oe — moon - a eae ae EN AOE SATE RAAT Oe

Page 48

POPULAR SCIENCE MONTHLY May, 1930 Striking Flashlight Portraits of Wild Life, ‘(Posed by Nature and Obtained by the Ingenuity of Camera Men IEC LOLA RENE ETE eta SSA SRP = egg A apsiatate . eo Posed entirely by Nature, this photograph of a bird in full flight is thought to be practically perfect from a technical and artistic viewpoint. Notice that the wings seem motionless and the camera proves that the feet hang down while the bird flies. itt misnneint ate ut. rj $y B~.! 4; ee Bil sie tt W 5 Tl i cinema en Fecteeth. eee These does were not posing for Aine aa Le i a A el A This startled fawn made a great effort to escape, but so fast did the camera work that the deer is caught in mid-air with its feet clear of everything but the splash- ing water, which, fortunately, did not spoil the unusual reflection. It is not praying. When the camera caught this thirsty hyena in Western Soudan, it was dis- covered for the first time that this strange animal kneels to drink. this night picture, but the photog- rapher stole up to them in a canoe and fired his flashlight. It was all over and they were filmed before they could move. This hyena, to its utter amazement, took its own picture. Tempted by hunger, it stole up to the cached food and, in the act of eating, moved a cord attached to a flashlight and-camera shutter. Notice there is no blurring, as the astonished beast had no time to move before the photo was snapped.

Page 49

1930 > be ings flies. ig for 10tog- in a it. It were move. May, 1930 POPULAR SCIENCE MONTHLY Mrs. Court-Treatt and her brother, Errol Hinds, are getting ready to hide a camera in the African woods. Waiting silently for the animals to come into view is the hardest part of this kind of hunting. Hunting wild things in Africa with a camera calls for great ingenuity. Major Court-Treatt, head of the picture-taking expedition, sent out by the British Instructional Films, used this and similar hide-outs in making his remarkable photographs. This young giraffe, still far short of the eighteen feet in height it may reach in maturity, was en- joying a nice meal in’ Africa when the camera got it. A little later In this nest, only Mrs. Court-Treatt’s face and the camera are its chase and capture were filmed. visible. So natural was this station, that animals would ap- proach within a few feet, as though wanting their pictures taken. A quiet drink at midnight, rudely interrupted by the glare of a flashlight. So swiftly does the modern camera do its work that these deer were photographed before they could even raise their heads. This speed emphasizes the tremendous change in photography during the past century. PROGRESS AND DISCOVERY

Page 50

SEY 02 Sa eS ite... -~."v. wneattinamee nats teed kate POA? it a Pere 48 Huge Turbines Will Give Ireland Cheap Power BEsIDE the Shannon River, in Ireland, a great hydroelectric plant is rising, which is expected to bring an era of cheaper electric power. The wormlike scroll cases that will contain the turbines are ready to be connected to the tubes or penstocks that will bring water from the river which at this point has a swift downhill flow. The illustration shows two of the scroll cases in place; a man on top of one of them, at the center of the picture, gives some idea of their size. The cases are solidly bedded in concrete to withstand the force of the rushing water. The pen- stocks will be bolted to these open mouths. Turbines of 38,600 horsepower will be installed in the center of the rings of pipe. Here fixed vanes, visible in the photograph, will direct the torrents of water against the blades of the vertical turbines. After use the water drops through wells into tailraces below. The great engines were built by a firm in Heidenheim, Germany. Florida Sees Chance to Grow Rubber THRIVING rubber planta- tions in Florida, now a hope, may yet be a reality. Para rubber trees planted there by the Florida Department of Agriculture are making en- couraging progress, says Dr. Karl F. Kellerman, associate chief of the Bureau of Plant Industry in a recent report. He believes rubber trees will flourish there as well as in Haiti, although in Florida latticework is necessary to pro- tect their growth. Haitian trees, he says, are as productive as those grown in the tropics, although not so vigorous. A plant from Madagascar, yielding a superior rubber of the Para type, is now being grown in the Department green- houses and in the Southwest. It is known as Euphorbia intisy, and in its wild state yields three to four times more than any other rubber. The plant is very rare and so far has not been cultivated on planta- tions. The Department, which now has only a dozen specimens, hopes to acquire more of the seeds. Whale Now Furnishes Leather for Gloves SEEKING to turn every part of the whale to profitable use, Norwegian whalers, with the aid of a Swedish chem- . ical engineer, have perfected a process of converting the huge mammal’s intestinal membrane into a tough, almost inde- structible, and cheap leather for gloves. Ships now sent to the whaling grounds are floating factories, equipped to extract the whale oil, remove the whalebone, store and bring back the edible part of the beeflike meat, and turn the rest of the carcass into fertilizer. POPULAR SCIENCE MONTHLY This relief map of England is one of the twenty sections of a huge world map to be shown at Antwerp. Ship mod- els, seen at the right, and 350 lights will give it reality. Largest Map of the World to Be Shown in Belgium A RELIEF map of the world, said to be the largest ever made, will be exhibited in the British government’s building at the Antwerp exhibition in Belgium this year. Built in twenty sections at the workshops of the Overseas Trade De- partment, England, the huge map is forty-six by twenty-three feet, and shows mountains, deserts, rivers, and all other geographical features. One hundred and eight model ships and 350 electric lamps will add reality to the scenes which the gigantic map depicts. The sections were packed in fourteen crates for shipment to the exhibition, and the cost, it is said, runs into four figures. At the Antwerp exhibition it is expected that practically all countries will be rep- resented with scenes of their industries and science. Robot Watchdog Fights When Light Hits It “Ropot” instead of “Rover” would be a good name for an electrical watch- dog, exhibited at the recent radio show in Paris. Robot’s bark and bite are as bad as those of its live prototype, provided it is confronted by a burglar carrying a flashlight. When a ray of light enters the May, 1939 These wormlike cases, on the Shannon River, Ireland, contain two 38,600-H.P. turbines. They will form part of a huge electric power plant. dog’s Iens-covered eyes, a photo-electri¢ cell in its head converts the light into an electric current. This operates three re- lays, each controlling a small motor. The first sets in motion wheels that rush the dog toward the light, the second opens and shuts its jaws, and the third startsa phonographic reproduction of a ferocious bark. The principle applied in the new watch- dog’s mechanism is the opposite of that used in the electric burglar alarm invented by Dr. Robert L. Burt, of the California Institute of Technology. This is set off when a ray from a concealed light, falling upon a photo-electric cell, is interrupted by the entrance of an intruder (P.S.M,, Oct. ’27, p. 51). While the Parisian watchdog offers no resistance to a burglar without a flashlight, experts who saw it said one could be made that would bark in response to noises like footsteps or the creaking of doors or stairs, on the Televox principle (P.S.M., Dec. ’28, p. 22). New Window Glass Brings Sunlight to Dark Rooms AN IMPROVED type of prismatic window glass has recently been placed on the market in London, England. Its purpose is to bring more light to those dwelling on the lower floors of skyscrapers or in near-by small buildings that are screened from the sun. Prism window glass has been used before to deflect the course of light be- tween tall buildings from a vertical to @ horizontal path so that the light could better penetrate room interiors. It is claimed for the new glass that it will per- mit the passage of approximately twenty- two percent more light than the old panes. It does this because the prismatic design of its surface shifts the path of light from the vertical to the horizontal by some twenty degrees more than the old glass did. The large prisms of the new glass admit of easy cleaning, and their bottom faces are curved to ensure wide diffusion of rays.

Page 51

River, They plant. electri¢ into an tarts a rocious May, 1930 A Hydro Plant That Rivals Niagara Falls ALREADY the second largest. hydro- electric power plant in the world, with 350,000 horsepower, -the giant Cono- wingo electric development on the Sus- quehanna River, Maryland, will, when additional machinery is installed, eclipse even Niagara, now the largest. From the humming dynamos of this plant, electricity under the terrific pres- | . x ~ 4a * POPULAR SCIENCE MONTHLY te Sc "a a Nemmee on eee wo wa ar 5 sure of 220,000 volts courses along trans- mission lines. Engineers expect that this center of energy will be an important link in future super-power hook-ups. ‘ é 4 MAN | %; : 4n8 TLL. iti iii —< ae

MIGAREACLTAES wy 6s ect EF SPE . FARETISARE ERE | A A row of huge generators with an output of 350,000 horsepower. The water turbine wheels are on the lower ends of the shafts Conant the generators. It is the second largest single hydro-electric plant in the world and will take first place when additions now contemplated are added. Conowingo’s nerve center, the operating room, where hundreds of meters and switches permit one man to control the enormous flow of electric current. PROGRESS AND DISCOVERY

The substation at Conowingo contains the largest circuit-breaking switches ever manufactured. Each of the units weighs 165,000 pounds. This huge installation is located atop the roof of the power plant.

A spare turbine runner or water wheel. One of them is used to drive each of the seven generators shown in the illustration at left. Comparison with the man gives some idea of the size of the wheel.

Looking across Conowingo Dam where the Susquehanna River is harnessed—a link in future super-power hook-ups.

se san ona go

2 — :

Page 52

ewe Ar eee, ¥ Rae ae ee 22 =" Neel ST tt at EO TEIN TE ks we RST ER ca Tet ads ee os ay TREE SO ean) ase ~ 2h ge 4 oe wis ow ARR: eu Tere € ar ¥ POPULAR SCIENCE MONTHLY Elevated Highways to Speed _ Traffic — * a New York’s auto highway, raised above the street on steel girders, will relieve traffic congestion. As THE end of the elevated railway in large cities draws near, the elevated high- way is ushered in. An extensive boulevard raised on steel girders, which has been in prospect for several years, is now in the actual process of construction in New York City. The highway will stretch from the Battery, the extreme southern tip of Manhattan, northward along the west side to Riverside Drive, which begins at Seventy-second Street. The purpose of this elevated roadway along the Hudson River is to provide for speedy traffic out of the downtown section by avoiding the congested streets. Film Developed for Movie Finds Carbon in Sun SELDOM, indeed, do movie producers aid astronomers, but Hollywood’s de- mand for a film ‘that would make day seem night resulted in spectrum photographs at the Mt. Wilson Observatory definitely confirming the presence of carbon in the sun. The story of this astronomical find was recently told at the Carnegie Institu- tion, in Washington, by Harold D. Babcock, scientist of the observatory. Movie producers sought a way to photo- graph night scenes by day so as to avoid the expense of powerful lighting required for night photography out of doors. Since photographs made by infra-red light give a black sky, they sought a film to take movies by the infra-red rays in sunlight. To meet this need, Eastman Kodak chemists found that films or plates bathed in a solution of neocyanin acquire sensitivity to infra-red light. Right here the astronomers stepped in, and took advantage of the discovery. They used the new plates for deeper ex- amination of the spectrum, the. scale of rays that make up the white light of the sun. The neocyanin plates not only made possible an extended study of the infra-red part of the spectrum, but furnished proof of the presence of carbon in the sun’s atomic make-up, Babcock explained. The few weak lines of carbon showing on ordinary plates were clearly recorded on the infra-red sensitive plates. a's + ag Res! = SE ‘Sunflower on a Tripod” Helps Tunnel Surveyors SURVEYORS who work below ground on tunnel construction jobs employ an in- strument called the “sunflower mounted on a tripod.” Its purpose is to take measurements from which engineers may compute the further need of blasting. An: adjustable rod projects from the hub of a small wheel mounted on a tripod placed in the center of the tunnel circle. This rod takes the radius of the tunnel at various points around its circumference. When these radius measurements are charted on apiece of engineer’s cross- lined paper, the completed figure resem- bles a sunflower, whence the name of the instrument. The measurements give the diameter of the tunnel from all an- gles, revealing any irregularities in the rock wall which must be blasted away to prevent encroachment on the cast-iron rings making up the shell of the tunnel. The ‘sunflower”’ little resembles its tele- scopic cousin used above ground, but it is just as much of a necessity to the surveyor. This instrument was used recently in connection with the building of a tunnel sixty feet under the East River, New York, to connect Fulton Street, Man- hattan, with Cranberry Street, Brooklyn. May, 1930 New Test Shows Spinach May Contain Vitamin A SPINACH may be a storehouse of vi- tamin A, according to tests by spectro- scopy, one of the newest branches of physical science. So Professors J..W. Woodrow and H. L. Cunningham, of Iowa State College, reported to a recent meeting of the American Physical So- ciety in Chicago. For the purpose of analysis, the spinach was examined in a liquid form before the spectroscope: This instrument is used in studying the bands of colored rays formed by the pas- sage of white light through a prism. Placed in front of the prism, the spinach juice was found to absorb certain definite rays of light from the spectrum. This is believed to indicate the presence of vitamin A. This is the first instance of detection of a vitamin by spectroanalysis. Previously such tests were made by noting the effects of food upon rats and other animals. Bricks Twenty Feet Long Made by New Process Bricks so large that several of them would wall a small bungalow may. soon be manufactured com- mercially. It is claimed that a new process developed by Professors J. P. Shaw and M. C. Shaw, of the Pennsylvania State College’s ce- ramics department, will produce blocks twenty feet long, five feet wide, and six to eight inches thick. Standard building and paving bricks both measure eight inches in their longest dimension. The object of the experiments was to find a new road building material. According to the dis- coverers, the huge bricks will pro- vide roads harder than concrete, cheaper than macadam, and faster to lay than either. The bricks will be red or buff in color, and will weigh 100 pounds to the cubic foot—a little lighter than average. The surface of small models made so far in the laboratory resembles paving brick. Electricity in the Air May Depress or Exhilarate Way do people feel exhilarated one day and depressed another without ap- parent cause? It may be due to a differ- ence in the amount of electricity they breathe. Evidence relating to the alter- ing amount of electrified particles in the atmosphere was recently presented to a meeting of the American Physical So- ciety by Professor Joseph G. Brown, physicist at Stanford University, Calif. His tests proved that the amount of loose electricity, or in other words charged particles of air, in each cubic foot is affected by rainstorms, winds, hot and cold waves, and similar changes in weather. Another peculiarity which he observed is that in air currents that are rising or falling, the change in the amount of electricity in the air varies rapidly. as = A & = ewe 8

Page 53

one ap- ffer- hey |ter- the oa So- wh, alif. May, 1930 ° POPULAR SCIENCE MONTHLY 51 The Art of Chromium Plating Shown, Step by Step, in Pictures AUTOMOBILE fittings, bathroom and soda fountain fixtures, tools, surgical instruments, and even pieces of modernistic metal furniture gleam these days with the brilliant, bluish-white finish of chromium plate, since the discovery of a way to plate this metal by electricity over other metals. Its surface may be made so hard that only corundum or the diamond will scratch it. Chromium plat- ing is said to resist rust, to withstand heat, weather, and abrasion, and to keep its luster indefinitely. The photo- graphs show the most important of the operations. First the article is “stripped,” or cleaned; by sandblasting or acid treatment. Then it is successively nickel-plated, copper-plated, replated with nickel, and finally chro- : F mium-plated. The object of the platings with copper and Articles to be chromium nickel is to secure a smooth, even coat of chromium. plated are first cleaned After each plating the article is polished. down to the raw metal by a blast of sand. Noz- zles are seen through the open door. Notice the heavy gloves protecting the workman’s hands. The copper-plating room where, after another polishing, articles are given a bath of copper over the nickel. This is followed by still another polishing and a second coat of nickel. Successive coats of different metals applied After sandblasting, and a thorough polishing, the article first gets in this way insure that the final coat, of chromium, will be smooth. The a coat of nickel plate—the basic coat on which several others will number of steps required in this rather complicated process is offset by be applied. Photo shows a plater removing a sword from nickel bath. the beauty, durability, and resistance to tarnish of the finished coating. This auto radiator shell was chromium plated in an 18-foot tank holding A group of men at work on the polishing machines. Articles are polished 1,360 gallons. Man at left controls rate of plating by regulating the after each plating, four times in all, to insure perfectly smooth finish. current. At right, a blower carries off the fumes of the plating bath. Note the various types of polishing wheels at extreme right of picture. PROGRESS AND DISCOVERY negate giio~iadonae--veion SIE RNP - Sr AA” SRT St RIEL OINSE = ARAL SOI EG a oS ro pee é wer _ oe yay a ele nine Rar eet }

Page 54

mn Nm Rouen Gets World’s Biggest Dredge from Germany RESEMBLING a squat battleship with giant conning towers and a tunnel bor- ing through its middle, the world’s largest dredge has been constructed at Liibeck, Germany, for use in the French port of Rouen. Weighing 2,100 tons and costing $625,000, it has forty-seven shovels, each capable of holding seventeen and a half cubic feet of dredged matter. Powered by its 1,040-horsepower engines, in sixty minutes it can dredge up enough material to bury a forty foot wide pavement a city block long under a layer of harbor debris two feet deep. From the port of Liibeck, where the dredge was built, forty miles north of Hamburg, Germany, to the harbor of Rouen where it will be put to use, is a long haul for the pygmy tug- boats that must take it there. Picture Sent 22,000 Miles Through Air by Radio THE picture of a rectangular design painted in black on a white card recently traveled 22,000 miles through the ether. It went to Australia and back again, in a test at the General Electric Company’s television broadcasting station at Sche- nectady, N. Y. About one eighth of a second elapsed between the time when the image was broadcast at Schenectady and its reappearance on a screen before observers, after its return journey from the Australian radio station that re- ceived and rebroadcast it. The image was, at times, distinct enough so that the rectangle could be recognized. This is believed a distance record for any television attempt. It was hailed by Dr. E. F. W. Alexanderson, General Electric television expert, as 2n indication that the problems of sending moving scenes by radio over great distances might be_solved if practical television over short distances ever arrives. ‘There are ripples in the ether such as there might be in a pail of water,” he said, “and I did not believe the picture would be distinct enough even to tell what it was.” POPULAR SCIENCE MONTHI Y PO ei ae — Gallon of Oil Runs Diesel Powered Auto 26 Miles SEVEN hundred and ninety-two miles on thirty gallons of fuel at a cost of a dollar and thirty cents, an average of twenty-six miles per gallon, is the recent record of a New York City man driving a car powered with a Diesel engine. The principal feature of the Diesel engine, long used in heavy marine service, is that it burns oil. Having no spark plugs, the engine works by the explosion of oil vapor within its cylinders, the pistons compressing the vapor until the heat induced by the pressure ignites it. Diesel engines, in spite of the fact that they use fuel obtainable at a little over four cents a gallon, have so far failed to demonstrate the flexibility of the ordinary gasoline motor. Hence they have not entered into general use for automobiles. New, Big-Yielding Corn Matures in 100 Days By CROSSING two corn families at the Connecticut Agricultural Experiment Station, Dr. Donald F. Jones has pro- duced a new variety of this important native grain of the western continent. It is claimed that the new corn, called “Canada Leaming,” will survive early frost, will mature within 100 to 110 days, and will give a bigger commercial yield. The six reigning types of corn—pod, ° May, 1930 pop, flint, dent, flour, and sugar—vary from one to seven months in their time demands for maturing. Corn is inval- uable as a food stuff in the raising of hogs, cattle, and sheep for market—one of the country’s greatest industries. Hence the importance of this new, early maturing variety of this vegetable. Earth’s Heat Is Not Great 30 Miles below Surface TuiRTY miles below the surface of the earth it is not much warmer than at the surface. That is the surprising con- clusion of two French electrical experi- menters, Conrad and Marcel Schlum- berger, recently reported to the American Institute of Mining and Metallurgical Engineers. Previously it had been supposed that the further the earth was penetrated, the hotter it would be found, and that near the center it had a fiery ‘core of molten material—a view given some support by temperatures encountered in deep mine shafts. The temperature rises, in vari- ous parts of the world, from about one degree to four degrees for every 100 feet of descent from the surface. Earth heat even prostrated workmen build- ing a railroad tunnel through the snowy Alps. The Frenchmen, al- ready known as inventors of a system for prospecting with electric- ity, were of course unable actually to measure the temperature directly at any such depth as thirty miles. But they de- vised an ingenious system of finding it indirectly. Electric currents were sent through the earth at great depths, between two electric contacts on the surface, and the resistance encountered by the current measured and used to compute probable temperature. Other magnetic studies recently suggested the Pacific Ocean side of the earth the hottest internally. Dr. D. F. Jones with fast-growing corn he devel- oped at the Connecticut Agricultural Station. est an lio 821 thi ot] rec Ze

Page 55

, 1930 —vary r time inval- hogs, of the ce the turing sat of the at the con- xperi- hlum- erican y and 1eers. irther rated, d be r the core view t by tered The vari- vorld, ee to y 100 1 the even yuild- nnel Alps. n, al- ntors ctric- ly to t any y de- ng it sent ween , and rrent yable udies side May, 1930 World-Wide Events in Aviation = » 6 % ‘ 4 ~ Batlike Airplane Will Carry Load in Wing FORERUNNER of giant ships housing passengers and fuel within the wings, unlike any so far built, a batlike airplane recently soared over Burbank, Calif. It pleased its designers by attaining a speed well over a hundred miles an hour, ac- cording to reports. The experimental machine, seating two people, was designed by W. K. Jay and John K. Northrup, also the designers of the fast Lockheed commercial mono- planes. It is of radical design, intended to cut wind resistance to a minimum. Be- hind the single wing, two spindlelike out- riggers support the tail with its two disk- shaped surfaces. A pusher propeller, in- stead of the usual tractor type, drives the craft, which has a wing spread of thirty feet and a motor of seventy horsepower. Future and larger airliners patterned after this ship, the inventors say, may inaugurate national passenger lines with 160-mile-an-hour cruising speed, and mail and express lines of 200-mile speed. The passenger planes would seat twelve, in rows of four abreast. Graf Zeppelin, in 50 Trips, Flies 72,000 Miles THE Graf Zeppelin, Germany’s great- est airship, has made fifty trips to date, and has burned up more than eight mil- lion cubic feet of fuel gas. It has carried 820,000 pieces of mail and more than thirty-five tons of provisions. These and other facts are reported in the ship’s log, recently -made public by the German Zeppelin company. In all, the craft has carried 1,574 per- PQPULAR SCIENCE MONTHLY This new batlike plane has no struts, fuselage, or braces to catch the wind. It is a pusher type, seats two, and has a 30-foot wing spread. Its inventors say it will revolutionize plane design. sons besides the crew, an average of thirty-one on each trip. It has crossed the Atlantic five times. Notable flights besides the round-the-world voyage last fall and. previous ocean flights have been a 4,975-mile cruise over Palestine and back and a 2,956-mile jaunt through the Balkans. In all, the ship has traveled more than 72,000 miles through the air, averaging approximately 1,440 miles on each cruise: . The Graf Zeppelin is now expected to visit the United States, by way of Brazil, sometime in May. A proposed expedi- tion for exploration purposes to the Arc- tic, scheduled for this spring, has been cancelled because of difficulty in obtain- ing insurance for the aircraft. Government Gives Michigan Airport Highest Rating Tue first “A-1-A” rating for airports, highest issued under Government regula- tions, has just been awarded to the municipal landing field at Pontiac, Mich. It is also the first of a series of ratings of hundreds of airports awarded by United States Department of Commerce officials after a program of inspections undertaken early last year. Such ratings provide valuable informa- tion to pilots visiting unfamiliar territory. The first “A” in the highest rating indi- cates that certain minimum standards of hangar space and general facilities have been met. The numeral “1” shows the rt to have at least 2,500 feet of effective nding area in all directions, or four wide landing strips of this length. Night lighting is shown to be good by the final “A” in the rating. 53 The “flying wing,” in a California test, made more than 100 miles an hour. This Menasco motor, with upside-down cylin- ders, develops 70 H.P. in the “flying wing.” New Plane Resembles a Powered Glider Moke like a glider than an airplane is a new light machine recently placed on the market. Its two-cylinder engine is claimed to burn less than two gallons of gasoline an hour, although it develops thirty horsepower. Great economy in running results. Also, the lightness of the craft enables it to glide long distances to a landing in case of motor trouble. The novel ma- chine sells for $1,880. Recent tests at St. Louis, Mo., are reported to have demonstrated its quick take-off and the ease with which it can be flown. Autogiro from England Has Roomy Cabin LaTEsT styles in autogiros, or ‘“wind- mill planes,” are exemplified in a new machine recently imported from England by the Pitcairn aviation firm, of Philadel- phia, which has undertaken the construc- tion of the planes in this country. The newcomer, unlike its open pred- on ga te pare 73 waits . ae =o th fp ote meee nef - a ee | | i

Page 56

54 The lower plane in this pic- ture is only a phantom and consists of a painted banner swung from the real plane. It is used in Germany for ad- vertising purposes but the army may adopt it for target work. ecessors, is a cabin craft. The roomy in- terior of the duralumin fuselage affords space for three passengers besides the pilot. A geared Wright motor drives the- machine. The landing gear is fitted with “air wheels,” a new type of balloon tire. The freely-revolving ‘“‘windmill” of four horizontal blades enables them to land or to take off in an extremely short space. In tests autogiros have flown at more than 110 miles an hour, and have climbed to 12,000 feet. Electric Flasher Is Used to Signal Plane in Fog A CHANCE remark by Col. Charles A. Lindbergh when he visited their research laboratory last summer, General Electric officials announce, has resulted in a new ground signal for aviators. Lindbergh’s observation was that “flashings made by the poles of trolley cars are noticeable when flying in a thick fog, even nena though other lights can- Ly not be seen.” Dr. Irving Langmuir, assistant di- rector of the laboratory, followed the suggestion and produced a new type of electric flasher, giving code signals so that it could not be mis- taken for a trolley pole. Other devices in cur- rent use for signaling aviators from the ground show a wealth of variety, a recent Government survey revealed. Some airports use colored flags; three western landing POPULAR SCIENCE MONTHLY Model shows how electric cablés laid on the ground outside airports may be used to aid flyers lost in a fog and searching for a hangar. Two loops of copper cables extend out from A the airport, from one of which dots are flashed and from the other dashes. These signals, detected by the aviator, are un- interrupted while he flies a true course.. A break shows he is off the line. Tests made on this model proved satisfactory. fields employ steel panels, red on one side and white on the other, to signal pilots. For night signaling, lights from a Very pistol and red and green lights on the wind indicator are- among the methods used. And this is called a safety device! Flying over Florida, James Terry demonstrates his contrivance for crawling to the tail of an airplane in mid-air and making repairs. May, 1930 Light Airplane Sets a New Altitude Record A NEw world’s altitude record for light airplanes was made when Barney Zim. merly, Marshall, Mo., pilot, recently flew his low-wing, open cockpit ‘‘flivver”’ plane to a height slightly more than five miles over St. Louis, Mo. Although his baro- graphs awaited official checking, they indicated that he had probably reached an altitude between 27,000 and 28,000 feet, far surpassing the previous German record of 22,500 feet. The term “light plane” as it applies to this record means planes of not more than 800 pounds’ weight, and includes the small private and sport craft that have recently become popular in this country. To sustain life in the thin upper air, Zimmerly carried two bottles of oxygen. Officials who watched the two-hour flight emphasized the fact that Zimmerly used a standard commercial machine of approved. type rather than an experimental design. The tiny Barling craft weighs only 735 pounds, carries.a useful or ‘‘pay”’ load of 340 pounds. Strange Events of Aviation A CHRONICLE of recent strange events in aviation would record the following: Levee guards near Green- wood, Miss., received orders to “shoot down airplanes,” occasioned by fear of aerial bombing of dikes that checked flood waters. Moorestown, N. J,, broker clung for his life to the tail of a plane while the pilot, unaware he was there, flew eight miles. The involuntary passenger had helped hold back the start- ing plane, and failed to let go in time. He was unhurt. It was aviation’s second incident of the kind. The Luke Field, Hawaii, pilot who for- gets most often to put out the wheels of his fold- ing landing gear when bringing down an am- phibian plane on dry land, will win a loving cup, made of wood, do- nated by the command- ing officer. So far six absent-minded pilots, none ‘of whom has been injured, have qualified for this doubtful honor. The first sea rescue involving an airship was the feat of the com- mercial blimp Vigilant, which reported to Coast Guardsmen a man and woman adrift off Tampa, Fla., in an open boat. A patrol boat rescued them. ite MA wo tor cal far eq it j sug bes bei the Mi ate pre

Page 57

, 1930 L ‘light Zim- ’ flew plane miles baro- they iched 8,000 rman ‘light neans unds’ the craft come thin Tried 1 the sized nerly rcial ental rling inds, load cent tion ng: een- ders es,” erial that J.; » the ilot, flew tary ‘art- ime. ‘ond for- put old- hen am- dry ying ind- six ots, een fied or. cue was ym- wnt, past und pa, | ied

May, 1930

POPULAR SCIENCE MONTHLY ugar from Sunflowers Jerusalem artichoke tubers from which sugar is extracted. Government Experts Find Cheap Method of Producing ‘‘Levulose’’ By ROBERT E. MARTIN ton, D. C., is one of the most re- markable sugar factories in the world. It will produce three fourths of a ton, each day, of a new kind of sugar called the finest in the world—sweeter by far than the best table sugar, at least its equal in food value and healthier, because it is the kind Nature meant man to eat. The raw material from which this strange sugar is obtained is a species of sunflower, best known as the Jerusalem artichoke. The new factory is an experimental one being built by the United States Bureau of Standards, Frederick J. Bates, Chief of the Sugar Section, told POPULAR SCIENCE MontTHLY. For two seasons it has oper- ated a much smaller one by the same process. From the plant now being built the experts of the Bureau of Standards hope to gather enough data to design a commercial factory. There are various kinds of sugar, one of which, fruit sugar, is the sweet substance in most ripe fruits and in honey. It is also known to chemists as “‘levulose.” Its pure, white crystals, indis- tinguishable from ordinary granu- lated sugar in appearance, are from fifty to seventy-five per- cent sweeter. A man who takes a lump and a half of sugar in his coffee would be satisfied with a single lump of fruit sugar, or levulose. It is the most easily digested kind, and Bates calls it ‘the finest of all sugars.”” Another Bureau of Standards expert, Dr. Paul Heyl, declares it the natural sugar man was designed to eat. It was in use, he says, up to the time of Columbus, when cheap- er cane sugar crowded it out. Only its expense has prohibited its manufacture today. If this little-known sugar could be produced at a cost that would compare with cane Nies.v.c completion at Washing- d sugar, it would undoubt- ree edly appear at once on , American tables. What- | ever plant it could be made from would be a profitable new crop for » ihe American farmers. For > tm these reasons the Bureau of Stand- ards set its expert chemists upon PEs Ta This filter press, in the Government’s experimental sugar factory at Wash- ington, D. C., is a part of the Bureau’s quantity production equipment.

ER a pare geo 55 the trail of plants that might be sources of levulose—then selling to rich diabetics who could not eat ordinary sugar, at from $30 to $110 a pound. They found the sugar, in a strange as- sortment of plants—the Jerusalem arti- choke, the dahlia, and such hardy weeds as the chicory, burdock, goldenrod, and dandelion. Of these the Jerusalem arti- choke was the most promising. When specimens were analyzed in the labo- ratory, more than two thirds of the solid matter dissolved in. the juices often turned out to be levulose. The discovery gave this misnamed plant new interest. It is not an artichoke at all, but a sunflower. It is only a distant relative of the true, or globe, artichoke commonly used for food. Nor has it any- thing to do with Jerusalem. It is of American origin, but the name “Jeru- salem artichoke” is probably a corruption of the Italian name for the plant, girasole articiocco, which means sunflower arti- choke. Tubers that form its root are the

rr In this machine, in- vented by Bureau of Standards experts, the sunflower tubers are sliced as the first step .in the process of get- ting out their levulose. edible part, while that of the true artichoke is the cluster of fleshy leaves at the base of its flower. Indians of the upper Mississippi Valley and the East first cultivated the so- called Jerusalem artichoke for food. An “artichoke chip,” resembling a potato chip, is manufactured from it today, though it is mainly cultivated as a_ livestock food. This is the odd plant in which the Bureau of Standards found a sugar which, in its own opinion, may largely replace the world’s entire sugar supply. (Continued on page 150)

were eS: SEALS. 3%. < 2 c. cee rages : ners pes ere AS en ee Sue TENSES ese hte Ss ror Ne FR ERI Pe EE 4 ea

Page 58

5 1 )° POPULAR SCIENCE MONTHLY Beavers Rule on Mars? No trace of human intelligence has been found on the red planet, and it is thought that evolution, through lack of the stress that helped on earth, may have halted with some animal adapted to a land and water life. By THOMAS ELWAY ARS is so like the earth that men might live there. It has air, water, vegetation, a twenty-four- hour succession of day and night, and daily temperatures no hotter and nights not much colder than are known on earth. But because Mars has no moun- tain ranges and probably never had an Ice Age, it is considered highly improb- able that it is inhabited by manlike crea- tures or by any that possess what men call intelligence. The evolution of life on Mars must have been different from that on earth. One of the best signs of intelligence on Mars, Dr. Clyde Fisher, of the American Museum of Natural History, New York City, said recently, would be some indica- tion of artificial light on the planet. Un- doubtedly, lighted cities on Mars could be seen through the telescopes now in use. However, there is one condition that prevents satisfactory and conclusive ob- servation. When Mars is closest to the earth, both planets are on the same side of the sun. Then only the sunlit side of Mars is seen. To see any part of the night side of Mars, observation must be made when it is part way around in its orbit toward the far side of the sun, so that a slice of both the dark and the lighted sides can be seen. When even a part of the night side is visible, Mars is relatively far away and difficult to see clearly. The Martians, if there are any, would not have equal diffi- culty in observing the dark side of the earth, for when the two planets are near- est to each other, the earth is showing Mars its dark side. ‘PuESE consequences of the orbits in which the two planets move might make it difficult for the dim glow of lighted Martian villages, were any such in exist- ence, to be detected from the earth. Cities as bright as New York or Paris, on the other hand, undoubtedly would be vis- ible. With the new 200-inch telescope which, it is planned, will be erected in California, it surely would be possible, Dr. Fisher predicted, to distinguish such brightly lighted cities, if any such Mar- tian centers of civilization exist. If such artificial lights are never seen, he added, it might go a long way toward proving that Mars does not possess intelligent life. Other students of the subject, how- ever, say it is possible that Martian civilization may correspond to that of an earlier, pre-artificial light era on earth. In any case, astronomers agree that there is a practical certainty that Mars possesses kinds of life below human intelligence. Any deduction about the life forms on Mars or other pian- ets, in the opinion of leading astronomers,

must start, if it is to be at all reasonable, with the idea of the distinguished Swed- ‘ ish scientist, Dr. Svante Arrhenius, of one kind of life-germ pervading the entire solar system. There is no reasonable way even to guess the form of this life-germ. It may, perhaps, have drifted, as tiny living spores, from planet to planet, whirled through space by the pressure of light. Whatever its form, the life-germ, biologists assume, probably developed on Mars, much as it did on earth, in oceans which have evaporated in the course of ages. Early conditions on the two planets are supposed to have been very similar. The theory that Martian life evolved along lines similar to those followed by evolution of life on earth is supported by at least one definite fact. Careful spec- troscopic studies at Mt. Wilson Observa- tory, near Pasadena, Calif., and _ else- where have disclosed that gaseous oxygen exists in the Martian atmosphere. The presence of oxygen gas is highly signifi- cant, since the only known way in which any planet can obtain a supply of this gas is through the life activities of plants. Following the lead of the great expert in Martian astronomy, the late Professor

2 sie ah —<* Big eyed, fast breath- ing beaverlike creatures may be the dominant animals on the cold and level planet Mars. Percival Lowell, astronomers long have recognized on Mars dark-colored spots and markings which are believed to be plains or valleys covered with vegetation. The oxygen which spectroscopes show in the Martian air is taken as another proof that this vegetation exists. Since the activity of plants is the only known process of cosmic chemistry by which free oxygen can be produced on the surface of a cooled planet, the presence of oxygen in the rarefied air of Mars indicates that vegetation there must have produced oxygen out of water and sunlight as it has done on earth. It is difficult to exaggerate the importance to Martian theorizing of the definite fact that Mars has oxygen and, therefore, vegetation. CERTAIN way along the’ path of evolution, Martian life shows evidence of having undergone a development like that on earth. What happened after that is a matter of deduction. The known facts about Mars are the fruits of years of astronomical observation and study. The dark and light markings on its surface can be seen through a large telescope. T-he lighter ones are reddish or yellowish and usually are interpreted as being deserts. The darker areas are green- ish or bluish in color and are universally ascribed to vegetation. Mars possesses

ee ee ee de ee ae ae! —_~_ aa pon aah

Page 59

‘AY, 199 yay, 1930

eath- tures nant cold Lars. have spots o be tion. w in roof only by the e of ates iced has rate y of gen of nce ike hat the ion ge or as n- ly

POPULAR SCIENCE MONTHLY

ays " eagint ro

\ a Es -< RICHARDS

Astronomers, peering through giant telescopes, have mapped Mars and named its various features. Note the polar ice caps, which change with the coming of the winter or summer. two white polar caps. Recent measure- ments of Martian temperatures by Dr. W. W. Coblentz and Dr. C. O. Lamp- land, at the Flagstaff Observatory, in- dicate that these are composed of snow and ice. In the Martian autumn these caps in- crease and become whiter. In the planet’s spring they shrink and often seem to be surrounded by wide rings of bluish or blackish material, which may be sheets of water or vegetation. Still more significant are the springtime changes in the planet’s areas of supposed vegetation. Many of these darken in color. Others widen or lengthen. Often new dark areas appear where none had been visible during the Martian winter. Few astronomers now doubt that these dark areas represent some kind of vegetation. S° FAR, everything runs strikingly parallel with evolution on earth. It is probable that it will be found to have run parallel farther still and that animal life on both planets, too, has been similar—for at least part of the evolutionary story. But during all the years of earnest and com- petent research not one clear sign of man- like life on Mars has been detected. Pro- fessor Lowell’s famous Martian ‘‘canals,”’ which for a long time were considered a probable sign of the intelligent direction of water, are now believed to be wide, shallow river valleys. This lack of manlike life is precisely what a biologist would expect. Man and man’s active mind are believed to be prod- ucts of the Great Ice Age, for that time of stress and competition on earth is what is supposed to have turned man- kind’s anthropoid ancestors into men. The period of ice and cold over wide areas of the earth was caused, at least in part, by the elevation of continents and moun- tain ranges. On Mars, no mountain ranges exist, and it probably never had an Ice Age. It is on these hypotheses that science bases its assumption that there is no human intelligence on Mars, and that animal life on the planet is still in the age of instinct. The thing to expect on Mars, then, is a fish life much like that on earth, the emergence of this fish life onto the land, and the evolution of these Martian land-fishes into reptilelike creatures. Finally, animals resembling the earth’s present rodents like rats, squirrels, and

Scientists no longer believe there are man- made canals on Mars, and think the broad bands are the wide beds of wandering streams.

A Martian, fit to stand 100 degrees below zero, might well resemble this creature. beavers would make their appearance. The chief reason to expect this final change of Martian reptiles into primitive mammals lies in the fact that on earth this evolution seems to have been forced by changeable weather. And Mars now possesses seasonal changes like those on earth. Pure biological reasoning makes it probable, therefore, that the evolution of warm-blooded animals may have occurred on Mars much as it did here. There seems no reason to believe that Martian life has gone farther than that. Mars is a relatively changeless planet. Biologists suppose that the rise and fall of mountains, the increase and decrease in volcanic activity, and the ebb and flow of climate forced life on earth along its up- ward path. Martian life of recent ages seems to have lacked these natural incen- tives to better things. Now, there is one creature on earth for the development of whose counterpart the supposed Martian conditions .would be ideal. That animal is the beaver. It is either land-living or water-living. It has a fur coat to protect it from the 100 degrees below zero of the Martian night. _ Martian beavers, of course, would not be exactly like those on earth. That they would be furred and water- loving is probable. Their eyes might be larger than those of the earthly beaver because the sunlight is not so strong, and their bodies might be larger because of lesser Martian gravity. Competent dig- ging tools certainly would be provided on their claws. The chests of these Martian beavers would be larger and their breath- ing far more active, as there is less oxygen in the air on Mars. Such beaver-Martians are nothing more than pure speculation, but the idea is based upon the known facts that there is plenty of water on Mars; that vegetation almost certainly exists there; that Mars has no mountains and could scarcely have had an Ice Age; and that evidences of Martian life are not accompanied by signs of intelligence. Herds of+beaver-creatures are at least a more reasonable idea than the familiar fictional one of manlike Martians digging artificial water channels with vast ma- chines or the still more fantastic notion of octopuslike Martians sufficiently intel- ligent to plan the conquest of the earth.

See eee ae a orn rte inset a wr enact meee se Oe ee oe a = aa ; tty Sw hs aan

Page 60

58 s Stunt Flying — By ASSEN JORDANOFF PILOT who can’t stunt is a fair- weather flyer. He is unfit to leave an airport unless conditions are ideal. He is unprepared for the emergencies of the air. A dozen times in my seventeen years of flying the ability to stunt has saved my life. Once, during the World War, I was limping home from the Saloniki front in a crippled Albatross. The 160-horsepower Mercedes had lost half its cylinders through sticking valves. It was popping and sneezing, getting weaker every mile. The ship was losing altitude. Below me, a river and a single-track railroad wound through a narrow gorge of the Balkan Mountains. The Albatross sank below the rim of this canyon. It dragged over a village, barely missing the roof tops. Then, before I could take advantage of it, the only available landing spot, a po- tato patch, slipped under my wings and was gone. I was too low to turn back. Ahead, the gorge narrowed to a pass hardly wider than the span of the plane. The river ran foaming between the jutting walls. No plane could thread that needle’s eye and live. The turbulent air would dash it against one of the rocky walls a few feet from its wing tips. Suddenly, a ter- rific gust, sweeping from the pass, struck the Albatross and carried it a. hundred feet straight into the air. That was my one chance. Kicking over the rudder, I plunged into the tightest corkscrew dive I ever made. I can still see a gnarled tree, standing between the river and the railroad, flash past my banked wings as I missed it by inches. This diving turn pointed the ship back down the valley and the momentum carried me to a safe landing at the potato patch. Nosane pilot,under ordinary conditions, would attempt a stunt like that. The chances are a thousand to one against him. POPULAR SCIENCE MONTHLY May, 1930 a s ad Jordanoff shows a student how the controls are manipulated in the chandelle, a sharply banked turn on the take-off, illustrated in the diagram above. He calls this the most dangerous maneuver in flying. The slightest error in judgment, the least sluggishness in the controls, the smallest downcurrent of air, would spell disaster. First, last, and all the time, the rule for stunting practice is: have at least 1,500- feet altitude. However, if I had- not practiced diving turns at safe altitude until I could perform them almost auto- matically, I would have been washed out in that Balkan pass. 6 nearer the ground a stunt is per- formed, the greater the danger. For this reason, the war- time chandelle—the zooming, sharply banked 4 turn on the take-off—is ~ one of the most treach- SIE Peer erous of all aerobatics. It requires hair-trigger piloting. A stall at the top of the zoom and the slfip plunges straight into the ground. War birds called this danger- Thrills of the Air Described by Veteran Pilot Who Tells in Detail How Plane Is Operated in Most Difficult Aerobatics ous maneuver the “T.N.T. Take-Off.” Yet, last summer, this same “dynamite stunt”? saved me from a bad crash with four passengers on Long Island. I was taking off in a high powered cabin mono- plane. The throttle. was wide open. I was halfway across the field. The ship was traveling nearly a mile a minute Then, without warning, a big plane lum- bered out on the runway directly across my path. I couldn’t stop and I couldn't turn without groundlooping my ship into kindling wood. I waited until the last second to get all the reserve speed pos- sible and then, just before the ships crashed, I zoomed into a chandelle, turn- ing as I climbed. We passed so close that the backwash of my propeller rocked the wings of the other plane. It is in situations like these that stunt- The plane above is at the top of the wingover stunt. As the ship zooms upward, it is banked and turned as sharply and steeply as possible. On the down glide both bank and turn are decreased until the plane levels off for flight. May

Page 61

ow “Ns ics >ff.” mite with was ono- ship ute. um- ross In’t into last 0S- lips Irn- hat the int- oes any : MONTHLY POPULAR SCIENCE toot | In this Navy maneuver, Boeing pursuit planes are flown in tandem fashion with thirty-foot ropes between them, making hair-trigger accuracy of operation essential to avoid collision. ing proves its value. More than any other kind of flying, aerobatics gives a pilot the skill, accuracy, and confidence to meet a crisis. It is not showi ing off; it is valuable practice. Stunting really began in 1913, when This plane is upside down in the barrel roll. In this stunt all controls are ap- plied and held on during the roll. Neutralize the elevators and apply the opposite aileron and ruci- der to stop the rotation. ~ OFA ~~ — the French flyer, Pegoud, climbed a Bleriot monoplane to 2,000 feet near Paris and looped the loop. Before that, steep dives, banks, and spirals just about completed the airman’s bag of tricks. I remember well the day Pegoud made his loop. I was with the world’s first war birds, the flyers who fought in the Balkan War of 1912- 1913. When the news of the feat reached us, the war stopped as far as we were concerned. We sat around and _ talked for hours. Most of the pilots said it must be a fake, as they did not be- lieve a wing upside down would support a plane, even for an instant. Shortly after that, I made my first loop—to win a watermelon. This was the way of it. While I was flying with the Bulgarians in the World War, we captured a fast Le Rhone- Nieuport from the French. I used to get up at daylight and fly it for fun, zooming of them said: ~~~ apy A Ford tri-motored.plane coming out of a loop ° at the All-American Air Meet at Miami, Fla. over the buildings and waking everybody up. Usually, when I landed, the other pilots would douse me with water as I entered the barracks door. One day one “If that plane is such a good ship why don’t you show us some real flying? I’ll bet!a big juicy water- melon you can’t loop her.” I took up the wager and hopped off with my teeth set. At 5,000 feet, I dove and pulled back the stick. Before I knew what had happened, the light ship shot up, over on its back, down, and I was leveling off again. I had looped the loop. INCE then, I have taught more than 200 students to perform loops and other stunts. The commonest mistake in looping, I have found, is pulling the stick back too far at the start. Another is let- ting the ship dive too far before leveling off at the end. I -begin a loop with a slight power dive to gain excess speed. Then I pull the stick back gradually, holding it against my chest throughout the loop until the ship is coming out and diving at approximately forty-five degrees. Then I begin easing it forward so it reaches neutral position as the nose of the plane rises to the horizon. At the _top of the loop, when the plane is in- verted, I cut the motor. At the bottom, when the ship is leveled off, I open up the motor gently. On the upward zoom, I watch the horizon as long as possible, because that helps me keep the wings of my plane level during the execution of the mancuver. An outside loop is one in which the plane makes a vertical circle with the wheels pointing in toward the center in- stead of a away from it as in the ordinary loop. It is performed by shoving the stick clear ahead while the ship is in a vertical dive and holding it there until the plane comes out right side up at the top of the loop. The queerest loop I ever made took place in the heart of a cloud. I wanted to test my sense of balance. I did. I couldn’t see beyond my wing tips, for the fog was thick as cotton batting, so I had no horizon on which to level up my wings. One wing was low and I didn’t know it. When I started (Continued on page 157) ——— ae ar msee. og - re ; PRAISE. a a See een ks LES Ls ant to loop, I slid all over the: ~s> Shot a acne! = Teac TF Saree $3 i Se oa a7 haw Set eaediat

Page 62

POPULAR SCIENCE MONTHLY % oa * ‘ May, 1930 chain of modern industry can be founc than the ore unloaders of the lower Great Lakes. Super-powerful crane monsters, grasping tons of mineral as easily as a hand clutches sand, these tireless slaves of the steel world trundle more than eighty percent of the total iron ore shipped in the United States. Four of the mammoth unloading cranes, 4 YEW more stupendous links in the such as are shown on the cover of this . issue, can transfer within three hours more than ten thousand tons of ore from boat to railway cars. In 1852 the first half dozen barrels of iron ore from the Great Lakes region was shipped to Penn- sylvania. By 1870 an ore carrier at one of the lower lake ports dropped a cargo of perhaps 300 tons. Many scores of stevedores working with shovels and wheelbarrows took a week to unload her. Today a vessel is eased of thousands of tons in no time, and the ore shipped yearly totals many million tons. Although the loading of ore is spectacular, it is the un- loaders that give the real thrill. Two types of them hold the field. First, there is the traveling bridge crane, so huge as to span a whole dockyard, which gobbles ore from the ship’s hold with a _ cable- suspended clamshell bucket. Ore-carrying vessels lying at dock at Cleveland, waiting for the unloaders, four of which can move 10,000 tons of the mineral in three hours. Monsters That Gulp Iron Ore Huge Machines, with Incredible Speed, Swing Vast Cargoes from Lake Ships in the Drama of Steel By STEPHEN SHERMAN The hoisting equipment to govern the bucket is housed in a trolley carriage that runs out along the bridge track to a mighty cantilever arm hovering over the vessel hatches. The trolley carriage may be run by motor drums placed in a stationary machine house, with the operator surveying all movements from a fixed point; or the operator may ride in a control cab suspended from the car- riage itself. The second and more spectacular type is the Hulett unloader, which is de- picted on the cover. In construction it resembles a colossal ‘“‘walking beam”’ of a river steamer with one leg lopped off. Mighty beams on these Hulett unloaders swing up and down carrying seventeen tons of ore at a load, filling and emptying once a minute. Its one leg is kept vertical by a girder brace hinged to the ponderous truck carrying the hundred-foot walking beam. Hence the name “stiff leg’? unloader is often used by Great Lakes captains in re- ferring to this device. [* IS this vertical leg that does the scooping of a vessel’s hold. Like the bill of a titanic bird it drops thirty or forty feet into a hatch, taking seventeen tons at one mouthful with the bucket at its end. Then it swings up and out of the hold to weighing scales and a car where it dumps its load. The car, when full, slides along a suspension track to a posi- tion over an ore car which an electric “shunt” puts into place. The ore car is started on its journey to the mills, and the swift routine is repeated. The Hulett unloader is con- trolled from a “brain center,” a little cabin three feet square where the unloader is directed by four switches, at the bottom of the vertical _leg just above the scooping bucket. The operator sitting in this brain center can run the whole giant back and forth along the squat trolley truck on which it rests, or move it sideways from hatch to hatch. A seventeen-ton load each minute is the pace generally maintained by nearly all of the unloaders. — MA I of the the ma tai the eq’ co’ clu wi ski

Page 63

rirder truck eam. ler is in re- > the ‘y or iteen et at f the re it full, posi- h an into d on and ited. con- ter, feet or is ches, tical ping ting | the orth -uck re it tch. -ach ally | of May, 1930 MONTHLY POPULAR SCIENCE POPULAR SCIENCE SCRAPBOOK News, pictures, and brief bits about unusual people, places, and things from all parts of the world are shown on the following pages de cass “ aad eye F a watt - r3 one, we ae “st ‘ : Fall a eS ee at eh Be GERMAN NATIONAL GUARD TRAINED TO USE SKIS SKIING on night patrols through forests of snow-shrouded evergreens is part of the work at the winter training camp of the German National Guard in Silesia. Near Hirschberg, southeastern Ger- many, the heights of the Riesen Moun- tains are utilized as a practice ground for the hardy guardsmen. With guns and equipment strapped to their backs, they make forced marches over the snow- covered passes, camping at night in clumps of evergreens that are weighted with masses of snow. Such training in ski work is an annual feature of the hard- ening of the infantrymen of the Silesian section of the National Guard. ANIMALS CROSSED PACIFIC 55,000,000 YEARS AGO FosstL remains of mollusks and other forms of marine life millions of years old have been found in the East and West Indies and in South America. Dr. Willard Berry, of Chio State Uni- versity, recently described these fossils before the Paleontological Society in Washington. His conclusion is that these immigrants to America came by way of the Pacific Ocean. He does not argue for a former Pacific continent as a land bridge over the present ocean, but thinks these creatures crossed when the water was shallow and warm. The marine animals described by Dr. Berry were chiefly from the Eocene period, and probably lived fifty-five million years ago. When the skiing Silesian soldiers rest, they build fires under the snow-covered trees. NEW BAKING POWDER LEAVES NO RESIDUE A FORMULA for a baking powder that leaves no trace of itself in the finished bread or cake has just been announced. It was originated by Edwin O. Wiig in the chemical laboratory of the University of Wisconsin. Its suitability for the gen- eral market is now receiving careful laboratory tests. The active agent in this new cake raiser has a powerful name, acetonedicarboxylic acid. During the baking process, carbon dioxide gas, in the form of minute bub- bles, raises the bread as does ordinary baking powder. Then the remaining por- tion of the new agent disappears as another gas, called acetone. Forced night marches on skis are part of the regular training of German guards in Riesen Mountains. FILM PHONOGRAPH CAN PLAY ENTIRE OPERA A PHONOGRAPH that uses a 400-foot reel of talking movit film as its “record” has just been perfected by Dr. C. H. Hewlett, of the General Electric Com- pany. On this reel of film, which is small enough to fit in an overcoat pocket, an entire play, opera, or concert pro- gram can be recorded. The invention is adapted from talking motion picture principles. However, since there is no picture to be shown, the entire width of the film is utilized for the sound records. In the present device, nine sound tracks run parallel for the entire length of the film, and when the film has run through once it shifts to the next sound track and repeats. These give a program of an hour and twenty minutes. The sound is recorded on the film, and reproduced in the long-playing phonograph, by simplified electrical ap- paratus similar to that used in the movies. WINDIEST SPOT ON EARTH FOUND IN ANTARCTIC AccorDING to Sir Douglas Mawson, British explorer, who headed an expedi- tion within the Antarctic Circle, the windiest spot in the world is Common- wealth Bay, south of Australia and sev- eral hundred miles west of Admiral Byrd’s Little America. Sir Douglas’ records were recently published in Aus- tralia. The average wind speed during the

Page 64

SR tae elt rere sence esas 62 twenty-two months the expedition main- tained a station at Commonwealth Bay was more than forty-four miles an hour. Speeds of ninety to one hundred miles an hour were frequent. At times, no records could be made because the wind recorders were blown away. PARIS STREET CLEANERS USE DUSTPAN ON WHEELS SHovutp this Parisian street-cleaning crew appear one morning in an American city, it might attract considerable atten- tion. A team of two men would be seen going down the sidewalks, cleaning up at a rapid pace. In front would be a brooms- man, sweeping refuse into small piles. Close behind would follow a man with a mysterious cart, which as it approached the heap would suddenly open its mouth, lower its under lip to draw it in like a dustpan, and close up again until another pile was at hand. When the container is filled with the sweepings, it is wheeled to a collecting station and emptied. This codéperative plan of street-clean- ing was recently put into effect on the famous Rue de la Paix in Paris, where visiting Americans marveled at it. TANNIN STILL IN CHESTNUT LONG AFTER TREE DIES THE domestic supply of tannin has been threatened by the blight of chestnut trees. But the United States Department of Agriculture, codperating with chemists of the tannin industry, finds that the trees retain their tannin content sometimes as long as twenty-five or thirty years after they die, although they soon lose their bark and sapwood. Prospects of finding and growing enough blight-resistant chestnuts to continue the extract industry are slight, searchers say. Work is being continued with promising trees and sprouts, although it appears that most chestnut trees, at best, are fortunate in merely escaping blight; they do not resist it. Tannin is used in the dyeing and tan- POPULAR SCIENCE MONTHLY ning industries and is the basis of ink and astringents. Chestnut extract contains fourteen to twenty percent of this val- uable substance. MEMORIAL HONORS MOTHER OF AIRPLANE INVENTORS IN CONSEQUENCE of the biography of the Wright brothers which John R. McMahon wrote for PoPULAR SCIENCE MontTuiy last year, a memorial tablet was raised recently in Hillsboro, Va., the birthplace of Susan Koerner Wright, mother of Wilbur and Orville Wright, the inventors of the airplane. When Mrs. J. S. Grasty, of University, Va., read in PoputAR SCIENCE MONTHLY that the mother of the inventors was born in her State, she arranged with the State highway department to place a com- memorative marker on the highway lead- ing to Hillsboro, and later collected funds wove a Le wnat WRVERTORS OF THE APPL ANE wmmorray carnaniat orsceveey weer wasetur VEL WITED Ofer a, MiGHOET John R. McMahon, Wright brothers _biog- rapher, at memorial tablet erected recently to their mother and sister at Hillsboro, Va. for the memorial tablet shown here. The inscriptions on both marker and tablet were written by McMahon. The tablet stands above a spring opposite the site of the carriage shop of John Gottlieb Koerner, grandfather of the inventors. It is dedicated to the mother of the Wrights and to their sister, the late Katharine Wright Haskell. TERN FLIES 9,000 MILES IN FOURTEEN MONTHS A comMMON tern, member of the gull family, was banded in northern Labrador by Oliver H. Austin, Jr., in July, 1928. Fourteen months later it was seen and exdmined at the southern tip of Africa on*the Indian Ocean, 9,000 miles away, which is thought to set a record. The tern, or sea swallow, is usually smaller than the gull. Its bill is more slender, its feet not so strong, and its flight more graceful and dashing. The common tern is pure white with a cap and mantle of bluish gray and is sometimes hunted for its feathers. The all-white species live on Pacific islands; those with darker coats are widespread. May, 1939 MUSCLE TEAMWORK GREAT AID TO SINGERS SINGERS should take advantage of the natural teamwork between delicate vocal} muscles and powerful breathing muscles, if they would increase their range and im. prove their tonal quality. This is the advice of E. M. Josephson and Minnie K. Willens, who have been experimenting in breath and muscle control. The fine network of muscles in the larynx box which control the voice and the large, powerful muscles of the chest and stom- ach region work together like hands ona clock. Singers who aid this coéperation, instead of working against it, will sing better and with less effort and fatigue, it is reported. Three types of breathing are recom- mended for various ranges: for the high tones, a high chest breathing; for the middle tones, breathing which exercises the muscles of both chest and diaphragm; and for the low tones, breathing from the abdomen itself. Josephson claims that singing in this manner greatly improves the voice’s tonal range and quality as well as vocal resonance, and at the same time reduces the strain on the voice mus cles to a minimum. AMERICA’S SPONGE KING “Tue Sponge King of America” is the title given to Theodore Schroeder, of St Louis, the head of two companies having a combined business of two million dob lars. Only within the last fifty years has the sponge been classified as an animal, and not a plant. Marine sponges, the type used in the sponge industry, thrive in fairly shallow sea water (a few hundred feet deep) and grow in enormous colonies, varying in size, form, and color. Sponges are fished in the Eastern Mediterranean, off the Bahama Islands in the West Indies, and off the west coast of Florida. The “‘sheeps- wool” sponges of Florida are considered especially fine. For a thrilling story about Florida sponge fishermen in the Gulf of Mexico, see ‘‘Men Who Fight Sharks” (P.S.M, Sept. ’26, p. 32). Theodore Schroeder with a pair of large dried sponges, soon to be made into bath accessories. May, 1s cou! CATt 524 (A.

Page 65

LY, 1939 REAT > of the ‘© vocal] nuscles, and im. 1s the Minnie renting he fine 1x box large, . Stom- ls ona ration, 1 sing atigue, recom- e high or the ercises Tragm; m the > that roves ity as same mus is the of St Aving dok s has imal, | the llow and g in shed and eps ered rida ciCO, May, 1930 POPULAR SCIENCE MONTHLY 63 PROPOSED 200-FT. MOORING sassy {| EMPIRE STATE _ METROPOLITAN i 4 BUILDING, BUILDING, i | 1,065 FT. OVER 1,200 f 4 (A.0./93/) FL (A.0. 1932 CHRYSLER BUILDING, Sma 1,040 FT. Pak (A.0.1930) ' ‘ EIFFEL TOWER, 984.FT. (A.D. 1889) 'g: 4@:'3 igh, gets f98. gate bats WASHINGTON Rate MONUMENT Sth 555 FT. BHES (A.D.1884) Mr. 1 COLOGNE Bi ry CATHEDRAL, i 524 FT. ‘ Riis (A.D. /880) oe se SiG BS '& BMF Rs -* - » fe A: 4¢ = a ae * : = >GREAT PYRAMID OF CHEOPS, 461 FEET (4454 8.6. > 4a * ae a ae eee aes . a ¥ ty . es i « _ é © nage ong ott Ssixty-Three Centuries of Skyscrapers HEN the Chrysler Building in New York City recently reared its lancelike spire 1,040 feet above the street, it broke the 984-foot Paris Eiffel Tower’s forty-year record of being the highest structure ever built. Man’s aspiration to pierce the clouds dates back to antiquity. Skyscraping began about 6,400 years ago with the 461-foot Pyramid of Cheops. After a lull of more than sixty centuries, the Egyptian marvel was overshadowed upon the completion, in 1880, of the 524-foot Cologne Cathedral, begun six centuries before. Then, in 1884, the Washington Monument was com- pleted and surpassed the German edifice by thirty-one feet. Now towering structures of stone and steel. rising rapidly to dizzy heights, set new breath-taking records almost monthly. Structural steel made the modern skyscraper possible. The Eiffel Tower, built for the Paris Exposition in 1889 (P.S.M.., Oct. ’29, p. 49), was one of the earliest structures in which it was used. Two of its giant successors, beside the Chrysler Building, are shown here. The eighty-five-story Empire State Building, now under construction in New York City, will soar to a height of 1,065 feet, surmounted by a 200-foot dirigible mooring mast. This will be overtopped by the Metropolitan Life Building, New York City. The exact height of this mighty structure of a hundred stories, just begun, is not yet known, but it will exceed 1,200 feet. Fe Sse | — PE ASAE SRE ONG SAAS i: ORT RS SETIRS TAT TRI be ewig 7 asap

Page 66

RARE GLIMPSES OF THE SLEEPY DORMOUSE Montus of watching and waiting have earned for Dr. Ivar Arvidson, zoologist of the University of Upsala, Sweden, a remarkable collection of photographs of one of the most elusive and sleepiest animals on earth—the dormouse. Some of the best, reproduced on this page, illustrate strikingly the curious habits of this tree-living rodent. Living more like a bird than a beast, the dormouse builds a nest of leaves and grasses that would do credit to a song sparrow. At winter’s approach, it curls into a perfect ball within the nest and re- mains so until the warmth of spring starts the slow uncurling process and the quickening of its blood circulation. A sudden cold snap in the spring, and the dormouse roils up into a tight ball again. Of a very shy and retiring nature, this little animal is always hard to find. FIND SARDINES SPAWN OFF CALIFORNIA COAST RECENT discovery of the sardines’ spawning grounds is as important to the canning industry as to science. When fish are left to spawn naturally only fifteen percent of the eggs are hatched. When nourished in fish hatcheries, eighty per- cent of the eggs are saved. Sardines are no exception to this rule, and canners have long sought to learn where they go to spawn, in order to capture the eggs. The little herrings eluded their pursuers, but E. C. Scofield, scientific assistant of the California State Bureau of Commercial Fisheries, scoured the California coast from San Diego to Eureka, and finally tracked them to a place five miles off Point Vincent on the southern seaboard. Here he found schools of them and a great number of their eggs. Many small fish are called “sardines,” but the true sardine is a “pilchard,” a small olive-green member of the herring family, abounding in the Mediterranean and off the west coast of France. Sardines are POPULAR SCIENCE MONTHLY At left: named from the island of Sardinia in the Medi- terranean, where they are fished in great quantities. They are caught when young and, following cleaning, are washed, dried, and cooked in boiling oil. After the lids are soldered on in the canning, the tins are plunged in boiling water or steam before the venthole is sealed. This pre- vents bacterial decay. The largest sar- dine fisheries in the world today are off the coast of Brittany. 35-TON DOOR GUARDS BERLIN BANK VAULT A SOLID steel door, two and a half times as thick as the armor on the greatest battleships of the World War, swings on its massive hinges before a vault in a banking house at Berlin, Germany. The steel portal weighs thirty-five tons alone, and with its metal and concrete founda- tion the entire entrance totals nearly four hundred tons. , The designers of the door maintain that it affords complete protection for the valuables stored in the huge safe whose entrance it guards. fae ses A Berlin bank has this 35-ton door. It is 3 feet 9 inches thick and 7 feet 8 inches in diameter. Oval: Rolled in a ball the dormouse sleeps feet up all through the winter, Uncurled and come to life again he ventures to the end of a twig, Above: A rare flashlight of the little fellow peeping from his birdlike nest, MORE TIN IN BELLS, LESS DIN IN CITIES ENTHUSIASTS in the antinoise Cam paigns will welcome the announcement that much of the din and discord of lan cities can be abolished if the makers bells and whistles will only add a litth more tin to the bronze used in their man facture. It seems to be a simple cased the more tin, the less din, according to H. C. Dews, a British metal expert. — Expressing his views to the Instituted British Foundrymen, he said that fim bronze, containing twenty-five percentd tin, gives bells and whistles a finer an softer tone, less offensive than thos fashioned with less tin and more copper. If metal foundries will revise their for mulas, fog and fire sirens, ambulance gongs and motor horns, street car bel and telephones—even the alarm clock— may all have more musical voices, and the noise-racked public more peace. AMERICAN BATH DAY SHIFTS TO SUNDAY HAaBITs so personal as one’s daily bath might reasonably be considered safe from the statistical searchlight. But nol Figures of home accidents, recently at nounced by G. D. Newton of the Traveles Insurance Company, reveal that mor people take a bath on Sunday than on any other day of the week. Saturday is losing out. While records show a daily average of 120 bathtub accidents, about 170 occut on Sunday, over forty percent more that on other days. Speaking statistically, the weekly “bath curve” of the American public has its peak on Sunday, drops a little om Monday, declines further on Tuesday and Wednesday, rises on Thursday, sinks on Friday, and then on Saturday starts climbing to Sunday’s weekly maximum. POPULAR SCIENCE MONTHLY is always pleased to answer questions on any sub ject within its field, if readers will address their inquiries to the Information De partment, 381 Fourth Avenue, New York, inclosing a stamped, self-addressed enve lope for reply.

Page 67

POPULAR SCIENCE MONTHLY

e winter, hat 4 twig, eI ; mi ~ et é , , "Oi Wer An unusual photo snapped at Gatwick, England, when i fl Ss . the horse hit a barrier and crashed clear over it. + 1 a, i af » al se Can } : i ncement H an of lang aa jakers of o a a. litt 4 Ir many ( > case of ; rding to | rt. i titute of ' i He hat fine °. ; A } rcent.o ’ ? ; Se SRP , ‘ ner and : a a <a “*Ss* P hot OS i 1 those This may not be the best . Copper. way of clearing a stone bar- b eir for rier, but at St. Buryan Corn- i wall, England horse and O i bulanee rider went over like this and E ar bells both escaped. uninjured. tah clock | Unusual ere and the ee. / al [ S This woman rider beat her horse over the hurdle. en na RCE, GEE ee This jump at Newbury, England, turned into a nose dive for the mount and jockey when the hurdle proved to be too difficult. on

RMS i i A RRS

Bi An open ditch hazard stopped this racer but its rider kept right on going. Spilled by a head-spin that broke the jockey’s leg. POPULAR SCIENCE SCRAPBOOK

Page 68

66 RUNS 9-CYLINDER MODEL ENGINE, SIZE OF A HAND With 360 midget parts functioning perfectly, a model of a nine-cylinder radial airplane motor, that could be held on the palm of the hand, spun its tiny propeller at a recent exhibition of the Los Angeles, Calif., Society of Model Engi- neers. William X. Brown, the maker of the pocket-sized engine, says its measure- ments are correct to a ten thousandth of an inch. Besides the radial motor, he ex- hibited three types of steam engines made with equally minute measurements. Each of them, run by compressed air, worked successfully. His exhibit was only one of many, the Society having forty members, all enthusiastic model makers. SIGNAL TO MOON WILL TEST RADIO RANGE Dr. A. HOYT TAYLOR, chief of the radio di- vision of the United States Naval Research Labora- tories, announced recently that he will attempt to send a radio signal to the moon. Dr. Taylor hopes that the moon’s face will reflect the signal back to earth, where, since the moon is only 250,- 000 miles away and Hert- zian waves are supposed to travel 186,000 miles a sec- ond, it would be picked up & bana trp Rae POPULAR SCIENCE MONTHLY William X. Brown with his model engines shown at Los Angeles, in Washington two and four Calif. A nine-cylinder airplane motor with 360 parts is seen fifth seconds after its de- second from the right. Each of the other three is a steam engine. parture. Thisexperiment would set- tle the question of whether an electrically- charged layer in the earth’s upper atmo- sphere prevents the escape of radio waves. The supposed existence of such a layer has long been advanced as a barrier to an attempted radio communication with Mars. If successful, the experiment would set a new long-distance record for radio transmission. Another long-distance record was made recently when a radio program, broad- cast from Schenectady, N. Y., on a short wave, was picked up and rebroadcast at Sydney, Australia. After having trav- eled a distance equal to four fifths of the earth’s circumference, it was received, and broadcast once more, by another station in Schenectady. Thus the two Schenectady stations were sending the same program, but the one relayed, due to its long trip, was one eighth of a second behind the other. BROKEN WATER MAIN GIVES CITY A NATURAL GEYSER PEOPLE passing along a principal street near the north end of Manhattan Island, New York, one afternoon recently saw the asphalt pavement suddenly begin to heave and crumble and a moment later a giant fountain burst forth. The geyser roared higher and higher until its crest was level with sixth-story windows. A large water main had burst, resulting in this brief picture of a natural phenome- non. It was brief because workmen soon repaired the leak, stopping the flow, but thousands of gallons of water were lost. This geyser is roaring to the height of six stories from a broken main in New York City. May, 1930 BUILDS 36 MODEL SHIPS FOR WAR AND COMMERCE A MAN who commands a complete navy and mercantile marine of his owr creation is Major Arthur W. Kipling (above), an American living in Paris. His collection of thirty-six ship models in- cludes both miniature dreadnaughts and passenger. ships. Six of his models were shown recently at the Salon Nautique, or Nautical Show, and attracted much attention. HEAVIEST WELDED TRUSS HOLDS MILLION POUNDS THE theory that welded steel girders are as strong as those riveted, recently re- ceived a drastic test in the heaviest welded truss ever constructed. This steel framework was made for a Glendale, Calif., mausoleum. According to engi- neers’ computations, at the point of greatest stress it safely sustains a force of a million pounds. “Gusset plates”—overlapping plates at the joints—similar to those used in rivet construction were an unusual fea- ture of this heavy arc welding job. It is estimated that use of welded joints saved ten to fifteen percent in the quantity of steel used. NEW DISEASE IN ENGLAND DRIVES BIG DOGS CRAZY CANINE hysteria or dementia, a new dog disease, has recently become so wide- spread that the Royal Veterinary College of Great Britain has begun research into its causes, symptoms, and treatment. Its causes are so far unknown, but big dogs generally are its victims. The dis- eased’ dog may suddenly howl and rush off on a run of several miles, and perhaps will kill himself by crashing into an ob- struction. The disease first made its ap- pearance in England in 1924, but “run- ning fits,” similar in symptoms, have long afflicted American dogs. fan lan ent on “ lon tim Un dai

Page 69

te vr 1g n- id or rn rrmt~. er | — a ae GREENWICH CLOCK KEEPS TIME FOR ALL THE WORLD UNUSUAL pictures were recently taken giving glimpses behind the scenes at the famous Greenwich Observatory in Eng- land, which, by common agreement, has become the time reference point for the entire world. The observatory is perched on a hill at the point through which the “zero”? meridian passes, and from which longitudes are measured. “Greenwich time’? was adopted as the standard in the United States in 1884, and is dispatched daily from the United States Naval Observatory in Washington, D. C. The photographs taken at the Green- POPULAR SCIENCE MONTHLY 67 wich Observatory show the time disks where the clock-setting time signals are controlled and a “sidereal’’ or star clock. This sidereal clock gives the time meas- ured uniformly by the axial rotation of the earth as referred to a star. One com- plete rotation measures off a sidereal day. The clock is sealed in a glass case kept at a temperature of sixty degrees Fahrenheit. The observatory was established in 1675. England, during the reign of Queen Elizabeth, had become the greatest mari- time power in the world. To this fact the observatory owed its origin, as it was de- signed ‘‘to further navigation and the ad- vancement of nautical astronomy.” A curious feature is a magnetic pavilion, so placed as to prevent disturbance of delicate instruments housed in it by the iron in the main structure. At left is the standard star clock kept at Green- wich. At right is tablet marking zero meridian. At left. room from which all the world gets its time. Disks control the signals. Which Five Inventions Are Greatest? Announcing the Prize Winners and a Summary of their Selections in PopuLar ScreNcE Montuty’s February Contest HICH five inventions are the greatest? Everything from the alphabet to the vulcanizing of rubber. That is the impression received by reading the answers of hundreds of contestants, submitted in the prize contest recently announced in this magazine (P. S. M., Feb. ’30, p. 44). From these manuscripts the Editors of PoPpULAR SCIENCE MONTHLY, as judges, have completed the task of selecting the prize winners. The awards are listed here- with. Because of ties among the con- testants for the $5 prizes, under the rules of the contest a full prize was awarded to each of the tying entries. Therefore, in addition to the First Prize of $50 and the Second Prize of $25, there’are seven prizes of $5 each instead of five as originally announced. _ Sidelights of the contest were interest- ing personalities revealed among the con- testants. A high school girl of seventeen won one of the prizes. Another manu- script among the prize winners was sub- FIRST PRIZE, $50 EuGENE W. BLANK, State College, Pa. SECOND PRIZE, $25 E. B. Benson, Rock Island, Il. SEVEN PRIZES OF $5 EACH ‘Dr. HEBER Butts, Nashville, Tenn. Mary Dotores Dess, Baltimore, Md. Rap L. Farr, Athol, Mass. Joun D. Grestmer, Ardmore Park, Pa. S. S. Parxison, Broken Bow, Nebr. Louis H. Roppis, Jr., Washington, me. &. ELLA SHEFFIELD, Muskogee, Okla. mitted by an orphan girl of eighteen, studying at a school for the blind. Clearness, conciseness, neatness, and skill in presentation were factors on which the judges based their awards. Many of the contributions showed a surprising amount of effort and ingenuity in their preparation, and a high standard of ex- cellence characterized most of the entries. The prize winners’ selections of ‘“‘great- est inventions” makes an interesting tabulation. This was as follows: Printing and printing process, 7; electric lamp, 6; steam engine, 6; dynamo, 3; radio, 3; telephone, 3; Bessemer con- verter for steel-making, 2; cotton gin, 2; wheel, 2. Also the following, which received one vote each: alphabet, boat, cement, mari- ner’s compass, induction coil, microscope, money, plow, telegraph, telescope, vul- canizing of rubber. Thus, the leading selections among the inventions may be said to represent the basic aids to civilization of education, light, and power. They are followed by representativeexamplesof communication and of the manufacturing and structural arts. It might be hard to place in more appropriate order the fundamental gifts of invention to mankind. Sarees = Spa - PS SESPOTR eee ie 7) ¥ q = . ad i es) at | i ie ay % } f t ae | oe

Page 70

ee eee ' ' A I ' , | t ' 68 Home Conveniences That Save Time Abundant heat to get up by on cold mornings is provided by this aluminum electric heater. It can be carried easily from bedside to bath- room, and tucked against wall when not in use. Pushing a foot pedal swings open the door of this new refrigerator without stooping or set- ting food down when hands are full. A dial thermometer in front tells when box needs ice. POPULAR SCIENCE MONTHLY May, 1939 May, With this new sandwich board fillings are minced in the bowl, and then spread on the bread onthe flat surface. To cut bread, the board is turned, Servin js shov used t V7 . ~ 4 — . ‘ - Maret, ., to a {mee | -- Hot simy sup} star flow In this combination tray and serving table, the legs drop at the touch of a button; or they fold out of the way, to conserve space, when not needed. a Boiling water is quickly supplied at any hour with this electric teakettle that plugs into any wall socket. A thousand- watt heating unit is built into the base. This ‘simple appliance prevents a steaming bathroom and muffles the sound of running water. The nozzle slips over faucet; the water flows through tube and out the base, fill- ing tub beneath the water’s surface.

Page 71

¥, 1930 May, 1930 POPULAR SCIENCE MONTHLY ou : linced on the irned, Serving three purposes, this rubber squeegee js shown above as a sink scraper. It is also used to clean windows and to scrape plates. This electric dishwasher dries the dishes, too. An electric fan supplies the drying air which is heated by a hot coil. The device sets on the drain board when in use and under the sink when its job is finished. Hot water at any desired temperature is always ready with this simple electric heater. Independent of the main hot water supply, it is controlled automatically by an electric switch that starts the heater the instant the faucet is turned and water flows. Dial regulates temperature from 110 to 190 degrees. Quick and handy is this compact shredder and cutter. A semicircular grating of metal tape grates anything from apples to hard- boiled eggs, and removes corn from the cob. Broiling on this combination grill and skillet gives the chop or chicken the same delicious flavor as charcoal broiling. The cooking is odorless and greaseless; ribs at bottom hold the meat out of the grease, which runs down into grooves. A novel “laundry car” makes stooping unnecessary when hanging wash on the line. It rolls along carry- ing the clothes and pins at handy height. It weighs but seven pounds and folds into small space. It can be used as ahassinet or to hold the baby’s bathtub. j ———$__———f }—_—_—— 7) YU Anyone can keep his clothes in one place with this novel space saver. The special built-in rack holds hat, coat, vest, shirt, trousers, and tie. 69 These oilcloth curtain protectors keep curtains clean and dry when windows are up at night. In day- time they are rolled back and snapped to window, out of sight. wine ae eit i Taipan Sc te AG he ep eyo ney dal anh. enna negli ~ Shh phaetotr ee ee

Page 72

ARCHIMEDES Father of Applied Scienc ¥ ~ = me 33 Be ET es | Travis Hoke, Editor | Raymonp J. Brown, Managing Editor Artruur WaKELING, Home Workshop Editor Aurrep P. Lane, Technical Editor IsraEL Doskow, Art Editor E. E. Free, Contributing Editor | | Published Monthly by Popular Science Publishing Company, Inc., 381 Fourth Avenue, New York City. Single Copies Twenty- five Cents. In the United States and Its Possessions and in Canada, $2.50 the Year. In All Other Countries, $3.00 the Year. Let Science Decide Prohibition HE fact that there is a prohibition problem at all is little short of ridiculous. The whole question hinges on the effect of alcohol on the human system, and obviously this is wholly a scientific problem. Yet the subject has been so befuddled by politics, prejudice, bigotry, ignorance, and emotionalism on both sides of the question that the authoritative voice of science has been lost in the clamor. Why not stop listening to the rabid prohibitionists and the equally rabid antiprohibitionists and put the whole question up to the scientists? In spite of the oceans of words that have been printed on the subject, no one really knows what effect alcohol has on the human system. Let the scientists, definitely and conclusively, solve this problem. Let them dig deep into alcohol’s effect on the body and on the brain. Let them weigh the bad effects of liquor against the advantages. Some of the bad effects are only too obvious, yet it is probably reasonable to ask whether a custom that has persisted continuously since the dawn of civilization can be wholly bad. At all events, let’s throw out the emotionalism and get down to cold, hard, scien- tific facts! Small Animals and Big Names NLAMENTED and unsung, the remarkable title of Brachyuropushkydermatogammarus is lost to zoology and its textbooks. This was the name that a certain zoologist, Dybowski, proposed to fasten upon a small crayfish of Siberia. The crayfish could not protest, but fellow zoologists could and did. The International Commission on Zoological Nomen- clature, which had the final say in the matter, ruled “thumbs down,” and the name is officially banned. The zoologists’ aversion to pinning such a name upon a small crayfish is to be commended. But its rejection does not im- prove an alarming state of affairs. Already 160,000 separate families are listed in zoology. The names are increasing, with new discoveries, at the rate of 1,500 a year. What will zool- ogists do when the good old simple names run out? Will they resort to numbers to increase the number of combinations? Movie Records of Progress ITHIN the last few weeks the morning mail of the Port of New York Authority has contained more than one letter from private citizens urging that moving pictures be POPULAR SCIENCE MONTHLY May, 1939 made of two spectacular bridge-building feats. One is the Hudson River Bridge, with the longest suspension span in the world, which will join New York City with New Jersey. The other is the Kill van Kull Bridge, the world’s longest arch span, which will connect Bayonne, N. J., and Port Richmond on Staten Island, N. Y. As historical records, citizens urge, movies of these unique projects should be added to the usuaj written and statistical records. The letter-writers, however, did not know that the Port Authority was already doing that very thing. Cans of film resting in its office contain movies showing the construction of the Hudson River Bridge’s anchorages and towers. Cable spinning will soon be added, and the movie (expected to be of five reels) will be completed when the floor is laid. Meanwhile another film will depict the erection of the Kill van Kull Bridge’s steelwork, of which 800 feet of film have been exposed, Pumping Heat from Outdoors HERE are skeptics who doubt that in the future electrical age homes will be heated by electricity. Lack of efficiency, they say, will forever bar the use of electricity for heating in competition with coal or other fuel burned under a boiler. Considering that the maximum overall efficiency of the finest generating plants is only about twenty-five percent, and coal burned under a boiler in the home gives just about the same heat efficiency, the future of electric heating does not appear bright. However, as T. G. N. Haldane, a British engineer, recently pointed out in a paper read before the Institution of Electrical Engineers, the efficiency of electricity in heating can be in- creased between 300 and 500 percent by using the electricity to pump heat instead of to produce it. His idea, which appears to be scientifically sound, is- to convert the electrical energy into mechanical energy by means of motors and then use the motors to pump heat, on the Carnot principle, from a low toa high temperature. This would mean, in effect, to build an electric refrigerator on a grand scale and operate it backward. Enormous coils, perhaps forming part of the walls or roof, would serve to ab- sorb heat from the air, and this heat would be pumped in and transmitted to the air in our homes by radiators not differing greatly from the types now in use. Looking for a Better Sugar yer the trade-mark on the family package of granu- lated or lump sugar, we have grown accustomed to seeing the word “cane.’”’ So commonly is cane sugar associated with sweetening that it is hard to take seriously the suggestion that a better sugar, not a substitute, may banish it from the table. What that “better sugar” is, is not at all a matter of specu- lation. It is “fruit sugar,” otherwise known as levulose. It is sweeter than cane sugar, is thought to be more healthful, and looks exactly like cane sugar. Recently it cost from $30 to $110 a pound. Now expert chemists of the United States Bureau of Standards are well on their way toward making it available to everyone at prices comparable with cane sugar. As described on page 55 of this issue, they are learning to produce it in quantity. Whether commercial production is to follow remains to be seen. They Are Saying— Bt jeer: biggest thing the American people can do during the next year is to pay more attention to engineers than to politicians.” —Thomas A. Edison. “A New York skyscraper is a delightful and fascinating monument of folly.”—Alistair MacDonald, architect son of British Premier Ramsay MacDonald. “The suspension bridge is the bridge of the future. It will not be unusual to see 6,000-foot spans.’”—Ralph Modjeski, famous American bridge designer. “The world is menaced by a shortage of superior scientific brains. We no longer have the conditions which created the great scientists of old.”—Dr. Edwin R. A. Seligman, Columbia University. oe “Vital bodily functions are retarded from twenty to ninety percent by amounts of alcohol contained in beer and light wines.”’-—Dr. Francis G. Benedict, director of the Carnegie Nutrition Laboratory, Boston, Mass.

Page 73

anu- eing with that ible. ecu- It is and $110 u of le to ibed t in ains the 1 to ting 1 of ski, tific the ybia ety ight egie May, 1930 POPULAR SCIENCE MONTHLY 71 Circuits That Improve Tuning Selectivity Depends Upon Number of Tuned Stages Through Which Signals Pass, but Too Sharp Adjustment May Spoil Tone Quality By ALFRED P. LANE of vital importance. In fact, ability to tune-in a desired station without interference from others on adjacent wave lengths is, under modern conditions, absolutely necessary. However, sharp tuning is not the only requirement. ‘Too much sharpness is fatal to tone quality. If carried to theo- retical extremes, so that the receiver would respond only to a single wave length or frequency, speech would be heard as an unintelligible mumbling, and musical tones could not be recognized. A modern broadcast station transmits on a band of frequencies nearly ten kilocycles wide. ‘This width is needed for adequate and faithful reproduction of speech and music. The ideal receiver should, therefore, bring in the necessary frequencies on both sides of the rated wave length of the station and reject all others. Actually the best of modern receivers fail to meet such exacting re- quirements though they may, at some one point on the tuning dial, roughly approximate it. The portions of the transmission on each side of the specified wave lengths of the broadcast station are called side bands, and a great many radio fans have the impression that the how and the why of these side bands are too complicated for the average man to understand. This is not so, as the reason for side bands is simple. For good sound reproduction, it is necessary to transmit frequencies up to nearly 10,000 cycles so that the overtones of musical in- struments, which makes them Sei 2 in a radio receiver is Fig. 1. This factory-built pre-selector unit is wired as shown in Fig. 2. Note the trimming condensers used to obtain exact synchronism between the various stages. sound natural, may be included. These sound frequencies are impressed on the carrier wave frequency, and the resulting wave from the station actually consists of a group of frequencies, each one of which represents the sum or difference of the fundamental frequencv and one of the sound frequencies. Obviously, the lower the tone the nearer will be the transmitted frequency that carries it to the fundamental wave of the station; and conversely, the higher the tone frequency, the greater will be the diversion of the corresponding transmit- ting frequency from the fundamental wave length of the transmitter. HE sharper the tuning, the more tendency there is to cut all frequencies that differ from the fundamental station wave length; and because the frequencies representing the higher tone diverge farthest from the fundamental, extremely sharp tuning results in what is known as cutting the side bands and consequently the higher audible notes. Extremely sharp tuning, therefore, results in throaty voices hard to under- stand and musical instruments that sound hollow and unlifelike. The mellow tone is produced by side band cutting either through too sharp tuning or by actual TO GRID OF iST RE AMPLIFIER TUBE ances dbiaatlpeal + & Fig. 2. A good pre-selector circuit using electromagnetic coupling. Dotted lines indi- cate shielding. Constructional details for the amateur builder are given in the text. Fig. 3. This pre-selector circuit uses capacity coupling between stages. A two-gang condenser and homemade coils and shielding can be used. suppression in the audio amplifier end of the radio set. For the finest tone quality, a broad- tuning receiver would be desirable if it were not for the fact that there are so many stations operating. The radio de- signer seems, therefore, to be between two fires. If he makes the receiver broad enough to get the best possible tone qual- ity, he will be bothered with interference; and if he gets it so sharp that interference is impossible, then the tone quality will be bad. A partial solution seems to lie in the so- called band selector circuit, also referred to occasionally as a pre-tuning circuit. Other conditiens being equal, the selectivity of the receiver depends on the number of tuned stages through which the signal must pass. A single tuned stage sufficed in the days when only a few stations were on the air, but the modern set requires anywhere from three to five or even more tuned stages. Furthermore, the screen grid tube, because of its extreme amplification, has made it pos- sible to use tuned circuits without tubes. The signal passing through these tuned stages is separated from the waves of interfering stations even before it strikes the first radio-frequency amplifier tube of the receiver. Such a circuit is shown in Fig. 1. The incoming signal goes through three tuned stages before it strikes the grid of the first radio-frequency amplifier tube. A commercially built pre-selector circuit unit of this type (Continued on page 155) TO GRID OF 1ST RE AMPLIFIER TUBE say ees Pace eae a an a eect en nae ee Ser ae tthe, - Sart er re te ene stent ree sernerin:>-s nan pene etl ateanmnatce-xtpammasetpcamisi =

Page 74

POPULAR SCIENCE MONTHLY May, 1930 HELPFUL HINTS FOR RADIO FANS Tools That Will Save You Time Screw Drivers Fitted to the Job Essential to Good Work—How to Test a Dead Set OU will find some jobs in radio so difficult as to be almost impos- sible if you haven’t the right tools. You might, for example, spend a lot of time and energy in boring a hole through a piece of wood with a penknife. With a hand drill you can do the same job a lot better in a few seconds. Even a beginner knows enough to get a drill instead of abusing his penknife. Yet radio experi- menters often waste hours of time for lack of some simple tool designed for the out- of-the-ordinary job. One screw driver, for instance, cannot possibly meet all requirements. Although a single, well-worn screw driver often is the only tool of its type possessed by the radio amateur, much time and annoy- ance will be saved by investing in several special varieties. The illustrations on this page show three types of screw drivers that are particularly useful to the radio enthusiast, and, in fact, should be a part of the equipment of every home workshop. Often a screw has to be tight- ened that is located close to the side wall of a metal shield or some other bulky part. A long-bladed screw driver makes such a job easy. A short-bladed screw driver often cannot be used at all except by holding it at such an angle that the head of the screw is inevitably marred. Another apparently difficult job is to set up a screw where there is no room behind it to use the ordinary screw driver. A double ended screw driver of the right-angle type makes easy an otherwise ‘‘impossible” job. Such a screw driver is shown in the center of the illustration. This particular model has been ground down so that the working edges are as close as possible to the center line of the handle. Such screw drivers should be made double-ended so that the blade on one end can be crosswise of the axis of the handle and the blade on the other end set in a plane parallel with the handle. There are many cases where the screw cannot be got at directly or through a full circle. At the right of the illustration is a short, small screw driver that will be found particularly useful for a large num- ber of jobs. Set screws for shaft couplings, set screws on dials, and so on, are easily handled by this particular type not only because the blade is thin and narrow but also because the screw driver can be used in a restricted space. With any type of screw driver it is im- portant to keep the blade in good shape with a clean-cut, square end. A worn and consequently rounded blade often will slip out of the slot in the screw head almost regardless of the amount of pres- sure applied. A sharp and _ properly shaped blade requires little pressure to keep it in place. When blades become dull or bent grind them square again. No More Rejuvenation Many radio fans recall that in the days of battery operated receivers it was com- mon practice to rejuvenate apparently worn-out tubes. The 201A tube, for ex- ample, was the type on which this re- juvenation process was most popular and successful. The question arises as to what can be done to rejuvenate the modern These three special screw drivers will save much time and trouble. They should be in every radio enthusiast’s tool kit. —, A B C’s of Radio HE object of shielding a radio receiver is to isolate one circuit from another so that each can do its proper job without interference. The effectiveness of any shielding de- pends, in most cases, upon how com- pletely it is carried out, the conduc- tivity of the metal used in building the shields, and its thickness. Surrounding a coil with side walls of metal accomplishes something, but the shielding cannot be com- plete until a top and bottom are in- cluded. Furthermore, it is important that the top and bottom, and in fact all joints in the shielding, make good electrical contact with the side walls, and so on. Generally speaking, the more radio-frequency amplification obtained per stage in any given cir- cuit, the more complete must be the shielding. type of A. C. tubes used in electric sets. The answer is—nothing. The older battery operated tubes often became prematurely exhausted because the electron-producing material on the surface of the heated filament was used up faster than the supply could be renewed from the interior of the filament. The various “cooking” processes, otherwise known as rejuvenation, resulted in boil- ing out a fresh supply of electron-pro- ducing material. Modern A. C. heater type tubes, in- cluding the -24 A.C. screen grid type and the -27 heater, amplifier, or detector as well as the rectifying tubes and power tubes now in use, émploy a different type of material to supply the electrons, the nature of which is such that it will con- tinue to supply electrons through- out the normal life of the filament itself. If by chance an abnormally long lived filament is encountered, so that the electron-producing ma- terial actually becomes exhausted, there is no way to rejuvenate it, as the electron-producing material is all gone. In modern heater type tubes, the heating filament itself will last, on the average, as long as the electron-producing material on the cathode. When the Set Goes Dead ALTHOUGH radio service men claim that about eighty percent of the calls they get these days turn out to be tube trouble, there still remain calls caused by trouble in the set itself. When the set goes dead the first prob- lem is, therefore, to determine whether it is tube trouble, and in many cases it will save the time and expense of a serv- ice man if all the tubes are taken to the nearest radio store for testing. If, however, a test shows that the tubes are all right, then the set owner can either call in the radio service man or attempt to locate the trouble himself. Many times the difficulty is absurdly simple. For ex- ample, radio service men report that an astonishingly large number of service calls turn out to be a current supply plug dropped out of the wall socket or the an- tenna or ground wire come loose at the binding post. These, are troubles that the owner should find for himself. When the loudspeaker is not built as a unit in the same console cabinet with the set, there is thé chance that the loud- speaker plug has come out of the socket. Even in the complete unit receivers, the speaker cord tips usually are plugged into special jack sockets in the receiver unit.

Page 75

930 C en ise he up he ise il- ee >!

May, 1930 POPULAR SCIENCE MONTHLY 73 In Radio—Look before You Buy Careful examination is needed when an uninformed fan tries to get a cheap set. This article 4 tells what to look for in all “ L. the so-called bargain offers. « E uninformed radio buyer who looks for a receiving set at a bargain price is seriously handicapped. In- stead of a bargain he may find himself saddled with an ancient relic of a bygone radio era—a set that didn’t amount to much in its day and is of even less value when compared with a modern outfit. Of course, now and then there are bargains in radio equipment, just as occasionally a secondhand car appears on the market in such good condition that it is a real bargain. Usually, however, a bargain radio set is a bargain in name only. It is sold cheaply only because nobody is willing to pay a higher price for it. Sometimes, because of overproduction, the market is temporarily glutted and sets are sold at less than their intrinsic value. That is why the phrase “‘manu- facturer’s sacrifice on account of tremen- dous overproduction”’ appears so often in the advertisements of so-called bargain radio receivers. The dealers realize that the phrase, whether true or not, is a potent sales point. But there is a vast difference between a legitimate case of overproduction and the much more frequent condition that arises when the manufacturer turns out a large number of sets in an effort to clean up his stock of old parts and raise cash for further operation. The latter type of set often is merely an obsolete chassis mounted in a fancy cabinet. To the eye, the set is good, but what might be called the hidden value, which comes from care- ful workmanship and accuracy in adjust- ment, simply is not there. Or a lot of cabinets dropped from the line of one manufacturer may be fitted to the left- over chassis of some other manufacturer. The result is a hybrid that may look well but isn’t even worth the low price asked for it. The result is comparable to fitting a 1925 automobile chassis under a more recent body of some other make and calling the combination a new car. VEN when a radio set is a legitimate 4 bargain, there are drawbacks that the purchaser should consider. In many cases such sets are sold ‘‘as is,” and when service is given, it frequently is of a most sketchy nature. Even if good service is given for a specified period—say ninety days or so—sooner or later the owner will have to depend on a near-by dealer who has no interest in the set and may have no specialized knowledge as to how it should be repaired. Furthermore, the question of where to obtain spare parts may prove troublesome, especially if the THEY

P<. <9 Sage

manufacturer has gone out of business and the set is an “orphan.” When choosing a radio set the prospec- tive owner should con- sider it in terms of hours of satisfactory reception compared with the original in- vestment, the upkeep, and the possibility of getting quick and expert service. Be- cause a set is cheap in price does not signify that it will prove inexpensive on the basis of cost per hour of entertain- ment. Many old sets now being sold as bargains are seriously deficient in tone quality, selectivity, and sensitiveness. If it costs a certain sum per hour for inferior entertainment, while the best of entertain- ment from a modern set would cost only slightly more, then obviously the bargain set is no bargain. HE radio fan with considerable experience needs no advice to help him choose a bargain set. Because of his familiarity with the various makes and his knowledge of their possibilities, he will know if the set offered is good, and if the price quoted really is low. When investigating the merits of a bargain radio set, first make sure of the maker’s name and the model number. Find out if the manufacturer is still in business and selling modern sets. Check up on the model number to be sure that the set is not misrepresented and that it was made in the year specified, and not a year or two previous. Note particularly what type of tubes is used. If it is supposed to be a screen grid receiver make sure that it is not a phoney IRGAIN By JOHN CARR ALE LAST =—_

If the radio bargain hunter isn’t careful, he may be saddled with a relic of a vanished age. circuit worked with one screen grid tube. Check up on the power tubes used and also the rectifier tube. Avoid any set that uses nonstandard tubes. This means that the set must have type -24 A. C. screen grid, -27 A. C. heater, -71A, -45, -10, or -50 power tubes, and -80 or -81 rectifier tubes. The -26‘tube is becoming obsolete, although such tubes undoubt- edly will be obtainable for several years to come. EFORE the deal is closed the set should be checked for tone quality, sensitiveness, and selectivity against a modern receiver working under the same conditions and hooked to the same antenna. Of course, this discussion of bargain radio sets applies directly to electric type sets. The situation with regard to bat- tery operated sets is entirely different. There are plenty of bargains in battery sets today—new sets left on the manu- facturers’ hands when battery sets went out of style, and sets that. were traded in for modern electric sets. Since economy of upkeep is an impor- tant consideration in a battery operated set, choose one that uses the fewest number of tubes consistent with satis- factory performance. With a good out- door antenna, a four- or five-tube set will give results as satisfactory as can be had at reasonable expense for battery upkeep.

ue ts id on z a oe yeep ni ne a a re “te - oo a SS i —— “ _ ~ = a — ee -_ £ ‘ fs, ‘ ys

Page 76

74 Stop That Fool Honking! | Gus Reads a Lecture on Use of Horns and Tells When to Blow Them and When to LetThem Alone By MARTIN BUNN = HIS is the third trip this week to i get odd-sized tires,’ Gus Wilson grumbled disgustedly as the red light flashed on at a crossing and he brought the Model Garage service car to a halt. Joe Clark, his partner in the garage business, grinned cheerfully. “Never mind, old-timer,” he said, “it won’t be long now before most of the old crocks that use freak sizes go to the junk dealer. It’s a good thing not so many sizes are used on the new cars.” Gus merely grunted as he watched for the green light. It flashed on a second or two later, but just as he started to let in the clutch the traffic officer held up his hand to allow another car to make a left turn. The driver in the car behind imme- diately thumbed his horn button for a series of aggravating toots. “Must be Honking Harry,” Gus snapped to Joe as he stuck his head out to see who was doing the tooting. “That’s a swell horn you’ve got, mister,” he grinned, “but it won’t get you anywhere with the traffic cop that’s holding up this parade. He’s hard-boiled, he is.” Gus forgot the incident until a few days later when a car pulled up in front of the Model Garage. “Bet you Honking Harry’s busted his tooter again,’ Gus whispered to Joe as the owner of the car approached the two garagemen. “How about fixing my horn, Gus?” he asked. “‘Can you do it now? I feel lost without a horn.” “That’s how any motorist ought to feel, Mr. Blainfield,’”’ Gus agreed, as he lifted the car’s hood. “I guess we can take care of you right away.” “A horn is mighty important,” ob- served Blainfield as Gus got out his tool kit and started to take the horn mech- anism apart. “Sure, a horn is important,” Gus agreed, “‘but you don’t have to blow it all the time.” “Yeah?” grunted Blainfield. ‘How else are you going to tell people what to do?” ; “That’s just the point,” said Gus. “A horn isn’t to tell people what to do. It's POPULAR SCIENCE MONTHLY gif 6 fo» SS ndanienll a’ ; = JEXPRESS “That’s a swell horn you’ve got, Mister,” Gus grinned, “‘but it won’t get you anywhere with this here traffic cop. He’s hard-boiled, he is.” really only a warning signal to let other people know what you are going to do, and to me it’s a sign that you are a good driver if you know when not to use a horn as well as when to use it.” hare so,” admitted Blainfield, 4 “but it seems to me that it is always better to blow the horn if there’s any doubt about it. Then you are on the safe side.” “Not always,” Gus maintained. ‘“‘There’s nothing safe about blowing your horn and expecting that the fellow trying to cross the street is going to stop because he hears you tooting. Maybe he won't, and then if you slam him, the knowledge that you blew the horn is kind of cold comfort. “To my way of thinking a horn is an emergency signal. If you’re a good enough driver you'll handle your car so that the occasions when you'll have to + GUS SAYS— - OU can’t insult an auto driver by telling him his brains are in | his feet—if he’s wise he'll take it as a compliment. Plenty of brains in your feet will make clutch facing and brake lining last about twice as long as usual. Your right foot ought to know enough to get off the accel- erator in time to let you coast to a stop and save wear on the brakes. Your left foot, boss of the clutch, should know enough to let in the clutch gently and not try to control car speed by slipping it. And brains in your feet will make ‘em work to- gether when you start the car— right foot keeping the motor running just fast enough without racing and left foot making the motor take the load without stalling. blow the horn are few and far between. Just the other day I made a fifty-mile trip and just for fun I counted the number of times I blew my horn. The total was only three. Once was when a fellow started to cut in on me. Another time was when some kids were playing in the street and that time I blew it while I was still quite a way off so as to tell them I was coming. The third time was to warn a fellow who was backing into the space ahead of me that he was coming back too far.” “T never looked at it that way before,” said Blainfield. “Don’t you blow your horn when you pass cars? What do you do when you come to a crossing?” “C\OMETIMES I give one quick toot if J T have to pass a car and he’s too far out on the road,’”’ Gus answered, “but I never pass a car at a crossing nor just before a crossing. It’s a good idea to give a long toot before you reach a crossing if it’s a bad one, but it’s a lot safer to slow down so you can stop in time if there is another car coming. “T don’t claim that blowing a horn is always foolish,” Gus went on, “but a lot of it certainly doesn’t get you anything. The silliest honking is when you get tied up in traffic. The fellow at the head of the line is just as anxious to get on as you are. Blowing your horn doesn’t clear the traffic. Of course, there are times when the fellow at the head of the line doesn’t notice the green light. One short toot from the car right behind him ought to be enough without the whole line giving an imitation of Armistice Day.” “That’s right, too,” agreed Blainfield. “While you’re fixing that horn can’t you make it sound better?” “What do you want to make it sound better for?” (Continued on page 150) de ra) wa lit

Page 77

930 if it st if na rw ~~ eer er ee Re UD lee May, 1930 POPULAR SCIENCE MONTHLY 75 POPULAR SCIENCE HOME WORKSHOP Articles on Furniture, Models, Toys, Sporting Equipment, and All Forms of Craft Work—Better Shop Methods—T he Shipshape Home New Ideas for a Racing Flyer How to Build a Fuselage Model with Sweepback Wings—Has Two Novel Spring Shock Absorbers and a Rudder Regulator By HI SIBLEY WIFTNESS in climbing, speediness in flight, and simplicity of design make the flying model plane illus- trated a worthy addition to the many plans of model airplanes described in past issues of POPULAR SCIENCE MONTHLY. Its designer and builder is Takie Tabata, a fifteen-year-old resident of Pasadena, Calif., who has a long list of record-breaking models to his credit. The fast little plane shown has made hand-launched flights of 800 ft., and its designer is confident it will do over 1,000 ft.—a very satisfactory mark for a 5-oz. fuselage type ship. On the day the ac- companying snapshots were taken, there was an unusually high wind, but the little plane tore into the gale like an angry hornet, veered about gracefully, and came to a graceful landing. Two new features are incorporated in this model: double shock absorbers on the landing gear and an adjustable fin. To make the shock absorbers, the music- wire struts at the bottom are given four turns around a spike, forming a coil spring which serves as an auxiliary shock absorber; while two strands of rubber supported by a V-shaped, celluloid yoke under the fuselage act as the main ab- sorbers. This arrangement prevents many a crack-up that would otherwise result from a hard landing. Adjustable fin and stabilizer unit. The stabilizer is held with a rubber band around the fuselage. The fuselage is built up as indicated in the drawings on page 76. It is made entirely of % in. square, hard balsa longerons and bulkhead frames, with \%-in. soft balsa on the sides for formers and %-in. hard balsa fairing strips placed in the formers. The nose, which is made from a 134 by 2% by 2% in. block of balsa, is rounded with a bulge at the propeller shaft bear- ing. The front ends of the longerons are set in mortises so that they will be flush with the surface of the nose block, and the rear ends are drawn together and secured to balsa blocks, through the center of which passes an aluminum tube. The latter serves as a socket for the dowel axis of the tail fin or rudder. All of the fuselage frame members should be given a coat of model airplane dope Above: View of underside of plane showing open- ing to allow easy access to the propeller hook. : Left: Takie Tabata, the designer and builder, with his swift flying monoplane fuselage model. to serve as a size and to toughen them. Music wire. % in. in diameter is used for the landing gear struts, which are secured to the first and second bulkhead frames. The 2-in. hardwood wheels are held in place with small washers cemented to the shaft. Cut out the propeller blank from a block of hard balsa to the outlines shown. The blades of this need not be sanded extremely thin, as it is better from the standpoint of strength to leave them at least 4% in. thick. Make the shaft from %-in. music wire and secure it to the propeller hub in the manner shown in the double scale diagram. A short piece of brass tubing soldered to a nut and fastened with an ambroid type of cement to the balsa nosing is used for the shaft bearing. Note that this bearing must be in line with the rear hook. The dummy exhaust pipes are made from = ~ we = ’ ‘4 _ [ 5" a LAYOUT IN J4" SQUARES CLARK-Y RIB AIRFOIL SHAPE OF sae: Detail of the wing rib construction and draw- ing showing the general shape of the fin ribs. ee a eet ee

Page 78

76 The swift little monoplane can either be launched by hand or made to take off from the ground. 3%-in. aluminum tubing and attached to the nose block. The sweepback wing requires careful workmanship to get each half properly lined up. Note that the trailing edge is made of basswood, the leading edge of hard balsa 1 in. square, and the single intermediate spar of % in. thick soft balsa. A razor blade clamped in a wooden handle makes a handy tool for shaping the Clark-Y wing rib sections. A curved strip of bamboo joins the ends of the leading edges together, and short pieces of heavy music wire are used to join the intermediate spars and the trailing edges. Where there is likely to be any strain, bind all joints with thread afterapplying the cement. Sheet balsa \% in. thick is used for the wing, stabil- izer, and fin tips. The leading edge of the wing at the center should be raised 1% in. higher than the trailing edge by the interposition of a small piece of balsa. The wing should tilt ip at an angle of approximately 4°; trial, however, will de- termine the proper ad- justment. 5 i sean fin, which weighs less than % oz., has sheet balsa ribs and % by % in. leading and trailing edges. A %-in. CUT PROPELLER BLANK re—— !0 THIS SHAPE FROM «= (_g HARD BALSA ~ case POPULAR SCIENCE MONTHLY strip of bamboo to the shape of the trail- ing edge of the stabil- izer. To bend bam- boo, hold it a few inches above a candle flame, shiny side down, and shape it gradually with the fingers. The leading edge is made from strips of 4% by % in. hard balsa joined at the center with a bent strip of bamboo. A maple dowel % in. in diameter serves as a spar through the center. The stabilizer unit is secured to the fuselage by means of a rubber band looped over in the usual manner. Extreme care must be exercised in the application of the Japanese rice paper. Cover one side of one half of the wing and stabilizer at a time. Apply a thin coat of glue or bamboo cement to the top edges of the end ribs and then to the leading and trailing edges, but do not apply adhesive to the intermediate ribs. The glue can best be spread with the forefinger. Have a piece of the rice paper ready, an inch larger all around than the wing; draw it taut from rib to rib (end to end), and press it down on the glue, and tighten it crosswise. The underside of the wing is covered in the same manner except that the central section between the wing halves is covered on top only, E - = = = = May, 1930 being left open at the bottom where jt rests on the fuselage. The fin is covered in substantially the same manner. Separate pieces of paper will be re. quired for each side of the fuselage. Ap open panel is left at the bottom just back nol es nosing, and on both sides at the tall. When all of the paper is in place and the glue has dried, apply a coating: of wing dope with a soft brush. Do this in dry weather, and use a half-and-half mix- ture of dope and lacquer thinner. While the wing should be located some- where back of the second bulkhead, its exact position is determined by trial. pet twelve strands of 3%-in. flat rub- ber bands in place on the hook, detach the rear S-hook, pull the rubbers out to three times their normal length, and wind the motor with a _ mechanical winder. With a four-to-one winder, from 125 to 130 turns can be taken with a reasonable degree of safety. Mechanical winders can be purchased from mode airplane supply dealers, but a serviceable type is nothing more than a hand drill with a strong wire hook placed in the jaws. An egg beater also can be used. The plane can be launched from the ground or the air. If the plane dives, move the wing forward a slight distance, and vice versa. If the plane shows a tendency to nose into the wind, a slight adjustment to the rudder pin will prob- ably remedy the trouble. RUDDER - FIN sss SS =sssj 7 ” " “ r= a “ maple dowel, placed in back of the center, serves as an axis for the steer- ing adjustment. A short piece of light music wire is cemented to the for- ward end of the bottom of the first rib to engage in the holes of the alu- minum plate, which is cemented _ transversely to the top longerons. The small pinholes in the plate can be drilled with a short section of music wire ground flat at the end, the wire being chucked in a hand drill so that only about % in. extends beyond the jaws. This type of drill is also useful for drilling small ' " zi Lessssee=> - ‘ owe COIL SPRING AUXILi ABSORBERS - iW" TREAD — ep DETAILS RUDDER FIN DETAIL NS x B POINT Ye MAPLE DOWEL VIEWS _OF DOUBLE SCALE holes in many _ jobs where hard metal is in- volved. Bend a % in. square ‘INCHES Assembled scale views of the plane and perspective drawings of the important a dihedral of 2 in. as well as a 2%-in. sweepback. Note especially the construction of the coil spring shock absorbers. parts. The wing is double-covered and has Ma‘

Page 79

May, 1930 POPULAR SCIENCE MONTHLY 77 A Card Table by Hepplewhite Measured Drawings of One of His Most Famous Designs with Suggestions for the Construction of an Accurate Copy By FREDERICK J. BRYANT EFORE starting to build a re pro- duction of the Hepplewhite card table illustrated, the amateur cabinetmaker is certain to ask a few questions. How much will it cost to make? What is the commercial value of a table like this if purchased in a furniture store? What is the value of the fine antique table this drawing represents? If the right hinges are selected, and mahogany, white holly inlay, and mahog- any veneer are used, the cost should not exceed ten dollars. The commercial value will range from forty to seventy dollars, depending on how well the table is made and on the quality of the fittings used. A genuine antique table of this design generally sells for about two hundred dollars. b The materials needed are: 2 pieces of mahogany 34 by 18 by 36 in. for the top, 4 pieces of mahogany 15% by 154 by 27% in. for the legs, 1 piece of pine 314 by 10 by 3434 in. for the apron, 1 piece of maple 138 by 3% by 35 in. for the gate arm, 1 piece of pine 34 by 3% by 35 in. for the gate arm backpiece, 1 pair of card table hinges, 2 yds. of 14-in. white holly inlay, 18 yds. of %-in. slightly rounded hardwood. An inlay used on curved sur- faces may be dampened slightly to prevent splitting. Each corner strip should be mitered. A stiff-backed safety razor blade makes an ideal tool for this operation. All inlays and veneers should be glued two or three days before being scraped and sandpapered. The apron or curved rim which joins the front is made from a heavy piece of white pine. The outside surface, which is rounded, is covered with a thin sheet of veneer. A 34-in. bent rim can be used, but the heavier piece makes it easier to fasten the legs in place. The rim is veneered in one piece before the legs are fitted. One method of accom- plishing this is to dampen the veneer, glue it to the rim, and then rub it with a piece of hardwood. The other method is to use cauls, or forms, which in this case can be the scrap pieces of wood left in cutting the

When placed against the wall with the pivoted leaf raised as shown, the piece serves as an attractive console table. curve of the apron. The veneer is dampened to make it pliable and is glued in place in the usual way. Paper is placed between the veneer and the cauls to pre- vent sticking. For further details on veneering and inlaying, see P. S. M., Mar. ’29, p. 90, and Feb. ’27, p. 88. The top is made up in two halves, the upper leaf having a square edge while the lower one is beveled under (see drawing). The four legs

white holly inlay, and 1 piece of mahogany veneer 6 ft. long and 334 in. wide. Names of dealers handling inlay, veneer, and hardware can be obtained by sending a self-addressed and stamped envelope to the Information TOGETHER | DOVETAILED

WHITE HOLLY a

Department of POPULAR SCIENCE MONTHLY. Even with limited ex- perience in making furniture, one need not hesitate to begin this project. The inlaying and veneering are the only details which might cause some concern and, fortun- ately, in this particular case neither process is difficult.

LINE Z — é. + r / 2 FRONT

be used, as is now customary ‘| with mahogany, it may be 4 = advisable to put on a second coat of shellac to cover the inlay thoroughly. The work is then ready for two coats of varnish. If filler and varnish are not to be used, from four to six coats of thin shellac will probably be necessary. For further information on finishing inlaid mahogany, see P.S. M., Mar. ’27, p. 122.

aera ee ee Mes SSS a eae : . < Fas

Soke a ee. pee a ee

Page 80

I EW operations are more important in decorative metal work than hard or silver soldering. Silver solder is made up of silver and brass in varying proportions according to the melting point desired. It is furnished in wire and sheet form, the sheet usually being preferred. Gold solder is an alloy of gold and copper or of gold and silver. Pure gold may be soldered with 14-karat gold, but the special gold solders are generally used. Since brass melts more easily than cop- per, large work in copper is usually sol- dered or brazed with brass or with spelter made up of copper and zinc in varying proportions. Small pieces of decorative work in copper or brass, however, are usually soldered with silver solder. Iron or steel may be brazed with common sheet brass or silver solder. In the process of silver soldering, the metal at the joint is first scraped bright and clean, and the joint is tightly bound with heavy iron wire or clamped with iron clamps. Several typical joints are shown in Fig. 4. Powdered borax, mixed to a creamlike paste with water, is applied as a flux to both sides of the joint. For small work, such as jewelry, lump borax ground up

é PGR Bee PRR: cilia Fig. 4. Typical joints ready for hard soldering or brazing. Note how the bits of solder are placed.

POPULAR SCIENCE MONTHLY Fig. 1. The sheet silver solder or spelter is cut into small, square pieces. Fig. 2. Homemade soldering turntable with charcoal banked about the work. with water on a slate stone is used as a flux. The lump borax can be obtained from jewelers’ supply houses or can be made by melting ordinary household borax in an iron ladle and allowing it to cool. ° The silver solder, which must be perfectly clean, is cut into }¢-in. or smaller pieces (see Fig. 1). These bits of solder are then covered with wet borax and are applied with tweezers along the seam directly over the crack or joint and, when possible, inside the work so as to be protected from the direct heat of the flame. The work thus prepared is placed on a charcoal fire or set in a suit- able bed of refractory material, such as cinders, lump pumice, coke, asbestos, or pieces of brick. Heat the work very slowly at first to dry out the borax. The larger parts of the work should be heated first so that the metal at the joint is heated evenly. As soon as the solder melts and runs into the joint, the heating

red | must stop immediately. The flame should never be directed on the solder or spelter because it will secencaneoamnonsneue- May, 1939 of Silver Soldering Choosing the Materials— Binding and Clamping the Joints—Ways to Apply Heat and Clean the Work By EDWARD THATCHER burn off the protective flux and oxidize the solder. As in similar operations in soft soldering, the molten metal always will run to the hottest part of the work; hence the importance of heating both sides of a joint evenly. Silver soldered or brazed work is usually cleaned after soldering by dipping it while hot into an acid pickle and leaving it there long enough to remove the borax scale. Small work, such as jewelry, is placed in a copper pan filled with acid pickle and the pan heated until the pickle boils up about the work. If both hard and soft soldering are used on the same piece of work, the hard sol- dering should be done first, as the soft solder will not withstand much heat, It frequently happens that more than one joint is to be soldered on a piece of work. Unless both are to be soldered at the same time, the first joint should be protected with a thick coating of yellow

<a Fig. 3. Using a blowtorch in soldering work that is sup- ported and surrounded by charcoal in a soldering box. ochre mixed with water. Be careful, how- ever, not to get any on the second joint. If charcoal is used, the fire is built ina small forge, an iron bowl, or a basin of tin with holes punched in it (Fig. 2). The work is placed on the fire and the charcoal banked up about it to confine the heat where it is most needed. A pair of bellows is used to blow up the fire here and there to force the heating. Frequently a gas or gasoline torch is used in conjunction with the charcoal fire. When using charcoal, suitable ventilation should be provided. The method of using the blowtorch and soldering box is shown in Fig. 3. The box is lined with tin and thick asbestos to confine the heat. If much work is to be soldered, a revolving stand such as shown in Fig. 2 is of great advantage.

May, .

Page 81

cidize ns in ways work; ually 1g it aving porax ry, is acid ickle 1 sol- - soft heat. than ce of ed at d be ellow pay, 1930 POPULAR SCIENCE MONTHLY 79 Hydraulic Double Acting Exact Control Demonstrable Results Hl OUDAL ILILIE Mesos agg’ ea ble. -DYE* hydraulic le acting SHOCK pret H ERES WHY Houdailles give perfect ridin comfort —Houdaille control of spring action is always in proportion to the severity of each bump. The law of hydraulics plus Houdaille design assures this. .. eo ey — Chassis springs work both ypivard and downward —so do Houdailles . .. Aaa 'y' —A slight turn of a ine outside nut provides exact adjustment. — Drive any Hovdaile- equiped car over the rough- est conceivable read. That is the only real sy Insist On @ wm am ough Road rite for illustrate {/ € booklet. of comfort and safety. Houde Engineering Corporation Buffalo, N.Y. A DIVISION OF HQ@OUIDAIILILIE-IHIERSIHIEY corPoRATION PIONEERS AND WORLD'S LARGEST PRODUCERS OF HYDRAULIC DOUBLE ACTING SHOCK ABSORBERS

Page 82

POPULAR SCIENCE MONTHLY May, 1939 Fiints on Hanging Curtain -—-—- — ™ a Fig. 1. Draperies, carefully chosen and properly hung, go far to decorate any room. In this bay win- dow, the side drapes are supported by continuous rods and the inner curtains by individual sash rods. OME owners often find it difficult to hang curtains and draperies with that professional compe- tence required by modern high standards of interior decoration. English, Dutch, Colonial, Spanish, and other types of small house architecture test one’s in- genuity in arranging curtain rods at odd- shaped windows. After all, the decorative effect of dra- peries depends largely upon how the rods are placed. Round-top windows and windows that seem too narrow, too wide, or too short and high present individual problems, but the solution in each case is simple if the following methods are studied. They represent the everyday practice of experienced professional dec- orators. One thing that helps the home owner is the fact that it is now possible to select curtain rods and brackets to fit almost any style of window architecture, no matter how unusual or bizarre in design. Windows with Curved Tops. Win- dows that are half oval or half circular at the top should be fitted with rods that follow the curve faithfully. Regular flat rods can be pur- chased already curved, but it is also possible to obtain a narrow, solid sash rod, about %4 in. wide, which can be readily curved in the workshop with the aid of a paper pat- tern. To make the re- quired template, use Fig. 2. Curved rods can be obtained like that in the upper view to fit windows with bent glass such A standard triple rod is shown in the lower view. a sheet of newspaper as are found in towers and circular bays. (or several sheets placed together) and pin it to the top of the window. Carefully outline the curve at the middle of the casing with a pencil. Cut on this line with scissors and lay the pattern on a workbench. Drive nails 1 in. apart in the bench top, following the curve of the pattern, as’ shown at G, Fig. 4, page 82. Bend a length of the narrow rod about this form so that it matches the curve perfectly. A straight piece of the same rod is used at the lower part of each half circle, as at H. Substantial brackets support each end, and a screw hook is used at the top. The brackets and fixtures can be obtained from curtain rod dealers; in fact, certain fittings are sold especially for attaching curved rods to the window casings. Two correct methods of draping this type of window are shown at A and B, Fig. 4. In the first method the side drapes are fastened with hooks over the curved rod, with inner curtains on a flat rod. In Rods How to Drape Windows of Odd Shapes— Making Sash Look Wider or Narrower—Draw Cords By KENNETH B. MURRAY the second method, curtain material is shirred on the curved rod in a sunburst effect. A regular single or double flat rod is fastened to the casing flush with the bottom of the half circle for supporting the side drapes and inner curtains. Doors with oval-shaped glass are fre- quently found in houses having round- top windows. A flat sash rod is placed at the top, extending the full width of the glass. If the swinging of the curtain on opening the door is an annoyance, another sash rod may be placed at the bottom, with the curtain shirred between them. Steel Casement and Recessed Windows. Windows that are recessed in the wall, as well as those having casements of steel, are more of a problem. In both cases there is only the plaster wall on which to affix brackets, and plaster is not suited for driving screws. One way of meeting this difficulty is to drill and chisel holes in the wall and drive substantial wooden plugs into the holes, so that they will pro- vide a solid support for brackets. Painted to match the wall, they are invisible. Another method is to drill small holes for each screw and set into them special fiber plugs sold for this purpese. A more recently developed method is to use special bracket holders, either pur- chased or made from heavy sheet steel. These are screwed directly to the re cessed windew frame, or in the case of steel casements they may be bolted through holes drilled in the metal, as at C, Fig. 4. On re- cessed windows they project outwards for the depth of the re- cess and then are bent over flush with the wall. Holes are provided so that curtain rod brack- ets may be securely bolted in place. _ Devices of this kind are an improve- ment over fastening

Page 83

Y, 1939 r) lows ‘tng or yrds rial is burst at rod h the orting e fre- ound- laced of the in on other ttom, dows. ll, as steel, cases ch to uited eting holes oden pro- nted sible. holes ecial rd is pur- teel. wed : Te low ents Ited illed s at re- ; for re- are vith hat ick- rely this ve- ing a May, 1930 ‘Inferior SCREEN-GRID tubes ate decidedly false economy!” POPULAR SCIENCE MONTHLY WALTER E. HOLLAND Chief Engineer of Philco Says e RADIO ENGINEERS ADVISE: Replace all the vacuum tubes in your radio set with RCA Radiotrons at least once a year. This is the only sure way to maintain good performance and min- imize disagreeable noises and other troubles caused by inferior tubes. RCA Radiotrons will give you the maximum in selectivity, sensitivity and tone quality. Old tubes may impair the berformance of thenew RCA Radiotron THE HEART OF YOUR RADIO SET © This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. “Because the vacuum tube is vital to the performance of a fine radio set, we rec- ommend RCA Radiotrons for Philco Balanced Unit Radio. Inferior tubes can cause numerous difficulties which may nullify the result of most careful set engi- neering and construction. Inferiar screen- grid tubes are decidedly false economy. The importance of quality and precision of manufacture as in RCA Radiotrons cannot be over-emphasized. With RCA’ Radiotrons in your Philco Screen-Grid Radio you will get the utmost benefit from Philco Balanced Unit Construction. RCA RADIOTRON CoO., INC. HARRISON, N. J. Look for the red and black carton and the famous RCA trade-mark SST ans RR org ae ae

Page 84

82 the rods inside the recess, because the drapes hang against the wall at the sides and do not obscure the view er curtail light. This arrangement is, of course, in- tended only to take care of draperies; small flat sash rods should be screwed or bolted directly to the casements, top and bottom, for the shirring of light curtain material. Windows with steel casements may swing in or out. When they swing out, it is more practical to leave the casements without curtains and hang the latter in- side on a second rod underneath the drapery rod. When they swing in, it is better to use draw curtains, the mech- anism of which is described later. Sometimes an old-world effect is carried out by using tiers of small casement win- dows. To enhance the effect, place small sash rods at top and bottom of each individ- ual window. In this event the drapery rods are omitted. Double and Triple Windows. Regular flat rods, with extension sections if neces- sary, are used at multiple windows. The only difficulty is that the rods will sag in the middle, especially on triple and larger windows, unless intermediate sup- ports are used. These are merely screw hooks with extra long shanks. Whether to use single, double, or triple rods depends upon the effect desired. A single rod will support the inner curtain, and the draperies and a valance can be sewed to the hooks and hung on the same rod. Triple rods (Fig. 2) permit the inner curtain, drapes, and valance each to have a separate rod. Set 1 in. apart in this way, POPULAR SCIENCE MONTHLY the draperies have the appearance of miniature stage hangings. Then there is the prob- lem of bay windows and solarium windows (Fig. 1). Special bay- window rods are made to take care of any style; it is also possible to use rods curved “flatwise” to fit the windows (Fig. 2). The latter are more practical for contin- uous draw curtains. Indeed, it is desirable in the solarium or sun room to use con- tinuous rods for the length of each side, with supports where necessary. The con- tinuous rods are sold in 12-ft. lengths. Odd-Sha ped Windows. Where there are small windows at each side and above a fireplace, use smaller rods of the same type as those at the larger windows. Long narrow windows and short wide windows can be altered by adroit placing . sal FLAT CURTAIN ROD BENT AROUND NAILS DRIVEN IN BENCH Fig. 4. Two suggestions for draping round-top windows and a method of bending the rods; hang- ing draw curtains at a recessed steel casement window; how to make windows look wider or narrower. Fig. 3. A straight rod with draw-cord equipment; a new type of wrought-iron side- drape hanger with slides for drawing curtains apart; and a curtain hook (at the left). of curtain rods. When a window is long and narrow, place the brackets at the ex- treme outside of the window casing and as near the wall as possible; in extreme cases, on the walls themselves (Fig. 4 at F). This brings the drapes farther apart and gives an impression of width as at E. The opposite tactics are used with short wide windows; the brackets are placed ° inside the casing at the extreme top so that drapes will hide a considerable por- tion of the width (J and J). In older houses windows with oblong transoms are sometimes found, usually with colored squares of glass. The lower part should be draped independently in the usual manner, and two sash rods placed at top and bottom of the transom with curtain material shirred on them. The same treatment is given door tran- soms. Draw-Cord Equipment. It is in the hanging of curtain rods with draw-cord equipment that home workshop expe- rience serves the amateur decorator well. Rods come equipped with the necessary cord, weights and slides, as shown in Fig. 3. A good quality of cut-to-measure flat rod should be used. This can be cut with a hack saw to exact lengths. Do not place it in a vise for cutting, as the pressure tends to squeeze the flanges together, making it useless for draw curtains. Fasten the rods to the window casings with the usual brackets and elbows at the ends. Place a support in the exact center of each length, if necessary. The slides are made of metal and pass freely in the groove formed by the flanges on the back of the rod. Both cords and pulleys are concealed inside the rod, mak- ing the operation simple and smooth. In computing the correct length of a draw cord, measure the length of the rod, add three quarters the height of the win- dow (top to bottom of casing), and double the result. On the ends of the cord, tie draw cord weights by threading them on the cord and knotting the end. If these are of metal, they should be of the kind with a rubber bumper ring, which will save marring the wall and casing. An easy way to attach the draw cur- tains is by means of hooks. These slip into buttonhole tape sewed to the curtain, and in turn hook-into holes in the slides. With this type of equipment, draw cur- tains operate perfectly, without the clat- ter of the old-fashioned brass rings. All the mechanism but the rod is concealed. Vv 7 aa Ss DP =a or et et a= & me & — = 6 — ~*~

Page 85

le, tor DR he —_ or. wen SS Se May, 1930 Dont Let SPRING-SLA Blanket! Toss You | pena you pilot your motor car over a stretch of rough and ragged road, the chances are you do considerable bouncing. And it isn’t pleasant. It racks your car and razzes your nerves. Perhaps you wonder how in the name of heaven so many jolts and jars can sneak by your springs and give you such a pommeling. Perhaps you think your springs aren’t doing their honest duty. Perhaps you think _ shock-absorbers aren’t absorbing as they shoul But if you'll take time out to seek the real reason, you'll discover it right in that important few inches between your spring-ends—in your spring shackles. Ordinary spring shackles don’t allow springs to flex freely —there’s the nub o the thing. Often your shackle bolts are too tight or they bind, cramping the spring. Often the vary- ing degrees of friction from day to day wear make it mighty close to im- possible to keep your shock absorbers adjusted properly. So when you hit a bump, your springs don’t give vith the im a ther an back quick and hard. And you feel it! Ki x Of pS)3 THE FAFNIR BEARING COMPANY Ee NEW BRITAIN, CONN: POPULAR SCIENCE MONTHLY FAFNIR ws BALL-BEARING SPRING SHACKLES XS, y You get that objectionable Spring-Slap—that’s the cause of those punishing jolts and jounces that jump up through the driver’s seat. The remedy? A set of Fafnir Ball Bearing Spring Shackles. With these frictionless ball bearing shackles springs parry every thrust with never a slap-back. ou take the roughest roads with smooth-road com- fort. You scale the bounciest bumps with rocking-chair ease. You ride relaxed, rested. a’. Fafnir Ball Bearing Spring Shackles will give you an entirely new conception of how downright comfort- - ably a motor car can carry you. They do away with shackle squeaks and rattles. You never have to grease them. You never have to adjust them. They add miles to the life of your car. And they add safety— they eliminate the danger of let-downs from worn shackle bolts. Fafnir Ball Bearing Spring Shackles will enable your springs and shock absorbers to live a better and more useful life. They are standard equi ment on many cars. For a surprisingly modest charge your garage mechanic can put them on yours. Ask him about them. COPYRIGHT, T. F. 8. CO., 1970 The Fafnir Bearing Company New Britain, Conn. Please send me information about Fafnir Ball Bearing Spring Shackles. City State PsM1 7.30 83 pn pal 1A MET RIN RN RG? AH BS © . > ¢ ~ - ont eee Sm ee ae pt fo Se oro tg re ee RE eet £2

Page 86

84 Useful Hints for Car Owners Simple device will keep car from jamming hub caps and fenders— Poor-idling motor quickly cured with notch in butterfly valve leaky inlet guides may be fixed. caps often are caused by collision with the side walls in a narrow ga- rage. Figure 1 shows how to prevent such trouble by fitting guide bars that will keep the car away from the walls or door jambs in driving in or backing out. A couple of lengths of two-by-fours can be cut and mounted as shown in the illus- tration. Since it is desirable that the tires should not rub against the guide bars any more than necessary, place them just as close to the side walls as will insure keeping the mudguards, running boards, or hub caps from striking anything. If placed flat on the ground the two-by- fours will not prove effective because the tires will have a tendency to ride over them. On the other hand, if they are placed too high and the car is fitted with wire spoked wheels the spokes may be injured. Consider these factors when fitting them. .Be sure to round off the edges of the two-by-fours against which the tires will rub and see that they are planed and sandpapered smooth. Also note that the guiding two-by-fours should be fastened to the supporting sections so the latter are one quarter to one half inch back of the edge of the guiding bar. Bers «i fenders and mashed hub Curing Poor Idling THE effective opening past the butterfly valve, to allow the motor to idle at a slow speed, is surprisingly small. After the car has been in use for several years, the shaft on which the butterfly is mounted and its bearings become worn. The result is that the butterfly never closes to the same position twice running; in addition, a considerable amount of air leaks through

y

: BRAKE PEDAL 2 / (_ _ WRENCH

Fig. 3. The wrench, clamped to the clutch, holds brake pedal while adjustment is made. POPULAR SCIENCE MONTHLY Wig

How

~

ll Yy ——— ———_—_—_— © | nae me '

2'«4"( ROUNDED EDGE) y,

Fig. 1. Guide rails fitted in garage will keep car from the side walls. ZA ° “A : vel o)} | ‘sl Y J

WORN AND LOOSE SHAFT < ADJUSTING SCREW ~ 1S REMOVED —=— NOTCH VALVE SHAFT Fig. 2. With adjusting screw removed, file a notch in the buttertly valve to govern the idling speed of the motor, when the bearings admit air. |

around the shaft bearings. A simple way to cure this trouble is to remove the adjusting screw entirely so that the butterfly closes tight. File a small notch in the edge of the butterfly valve as shown in Figure 2. This notch should be filed in the side of the butterfly valve on which the low speed nozzle is located and the size of the notch will govern the idling speed. Wrench Holds Brake Pedal- A NOVEL and ingenious method of holding the brake pedal while adjust- ments are being made on the brakes is shown in Figure 3. By setting the wrench so that it is fairly tight on the clutch pedal shaft, it will hold the brake edal at any desired position so that the

POPULAR SCIENCE MONTHLY awards each month a prize of $10, in addi- tion to regular space rates, for the best idea sent in for motorists. This month’s prize goes to H. C. MeAninch, Durant, Okla., for his suggestion for method of holding brake pedal depress- ed (shown in Figure 3, at the left).

VALVE HEAD

Fig. 4. Spring and washer on inlet guides stop leaks. point is easily found where the brakes first begin to take hold. Curing Leaky Valve Guides THE operation of a gasoline motor is not affected by leaky exhaust valve guides unless the wear is so bad that the valves do not properly seat, but leaky inlet guides cause irregular running .at slow speeds and-make it impossible to get the motor to idle smoothly. Figure 4 shows a way to eliminate this trouble. A light spring is fitted over the valve stem and a felt or leather washer is fitted on the stem with a hole that will just allow the valve stem to slide. It is a good idea to place a thin metal washer between the spring and the felt, although this washer is not shown in the illustration. The light spring will keep the washer pressing against the top of the guide and prevents air leakage and the consequent spoiling of the mixture. This suggestion should prove useful on old cars where the expense of new valve guides is not justified. Wire Removes Broken Axle WITH some types of rear axles it is difficult to remove the broken end without tak- ing off the differential housing cover. Figure 5 shows how to accomplish this job with- out disturbing the cover. A loop is formed on the end of the wire as shown. The wire, of course, should be so stiff that the loop can be slipped down over the end of the axle. The slip noose arrange- ment will afford a sufficiently good purchase on the end of the axle to pull it out. BROKEN END

ENGAGING AXLE | Ce SMALL EYE FORMED ON WIRE

Fig. 5. A loop in a piece of stiff wire used to remove broken axle without disturbing cover.

May Pihke Wl hel a

Page 87

CLITITILiMW & 7) l ikes »S ris ides lves nlet slow the vsa ight ida tem ilve cea and wn will top and ure. ove lere lve ear ove ak- ing OW ith- | of ire, tiff ved the ge- tly of Faster —than the Twentieth Century to Chicago! Faster —from Coast to Coast than the Fastest Train! Faster —than the Fastest Train from New York to Miami! ANNON BALL BAKER—one of the most fa- mous road racers in America — has broken 19 road records with a stock model Franklin car — lubri- cated with Mobiloil. This proves, in a dramatic way, what thousands of motorists have already discovered about the New Mobiloil in their own cars, under run of the road conditions. This proved performance stands behind every quart of Mobiloil. The record of performance behind Mobiloil is greater than that of any other oil in the world. To make a practical performance record of long engine Jife and smooth economical running in your own car, drive in where you see the Mobiloil sign. Have the Mobiloil dealer drain and refill your crankcase with. the grade of Mobiloil especially recommended for your car. VACUUM OIL COMPANY Makers of high-quality lubricants for all types of machinery ath Mobilo POPULAR SCIENCE MONTHLY Cannon Ball Baker’s Road Records using Mobiloil June 1928 to January 1930 Los Angeles to New York and return 6,692.8 miles. 6 days, 13 hours and 23 min- utes. Clipped 10 hours, 36 minutes from Lookout Mountain, Chattanooga To top of Lookout Mountain and return in 20 minutes and 52 seconds. Beat the pre- vious record by 2 minutes and 39 seconds. Mount Washington, N. H. From Toll House to crest of Mount Wash- ington, America’s steepest accessible moun- tain, in 14 minutes and 49 3/5 seconds. Broke record by 2 minutes and 10 2/5 seconds. Columbus to Marietta, O. 114.5 miles in 2 hours, 5 minutes and 40 seconds, bettering old mark by 12 minutes and 20 seconds. New York to Chicago 840 miles in 18 hours and 5914 minutes. More than an hour faster than the Twen tieth Century Limited. New York to Miami 1,451 miles in 24 hours and 20 minutes. Beat Miamian Limited by 6 hours and 51 min- utes. Average 59.6 m.p.h, Mount Mitchell, Asheville 17.5 miles from Toll House to Camp Alice in 35 minutes and 35 seconds, clipping 5 minutes and 25 seconds from the record. St. Louis to Kansas City and return 240 miles from St. Louis to Kansas City in 4 hours and 3 minutes. Back to St. Louis from Kansas City in 3 hours and 59 minutes. Dallas to El Paso, Tex. 687 miles in 12 hours and 54 minutes, lower- ing old mark by 1 hour and 44 minutes. Los Angeles to Phoenix, Arizona, (Desert Derby) 892 miles in 17 hours and 47 minutes. More than 4 hours faster than the train time. Mount Diablo, California Double round trip up Mount Diablo. 46.4 miles, covering 1,172 turns, in 1 hour, 34 minutes. San Francisco to Los Angeles 412 miles in 7 hours and 32 minutes, beating his own record by 1 hour and 25 minutes. Salt Lake City to Los Angeles 765 miles in 14 hours and 5714 minutes. Broke record by 1 hour and 19 44 minutes. Pike’s Peak Six consecutive round trips up Pike’s Peak without a stop. 150.28 miles in 4 hours and 25 minutes, Continental Divide, Mont. 4.4 miles across main Rockies to the sum- . mit of Continental Divide and return in 18 minutes flat, averaging 14.66 miles per hour in second gear. Butte to Anaconda, Mont. 46.8 miles hg ry minutes and 56 sqoende, averagi' -68 miles per hour, 75.7 miles per hour from Butte to Anaconda. Great Falls to Butte, Mont. 180 miles in 3 hours and S¢it minutes. Clipped 46% minutes from old record, Ogden to Salt Lake City 34.2 miles in 30 caiputes and 17 3/3. seconde, hour. Clipped 6 averaging 67.8 minutes and Sow afthe of a second from old record, New York to Los Angeles beating by 8 hours and 29 minut oe, pomene b ey can be made via crack Twentieth Century and the . Motor not stopped once.

Page 88

ene nn oe aS | | POPULAR SCIENCE MONTHLY May, 1930 a for a Circular Saw Fig. 1. How a hammer and an iron disk are used to obtain the necessary set. HEN properly used, a small circular saw is capable of doing the greater part of your cabi- network. For a saw to give maximum efficiency, however, the blade must be in first-class condition. Dullness of any cutting tool is not only a detri- ment to fine, accurate work, but a handi- cap to the worker as well. For, strange as it may seem, a dull saw is more likely to cause bodily injury than a sharp one. There are two main steps in the sharp- ening of a saw. The first is to give the teeth “set” or clearance, and the second is to file the teeth to sharp, uniform points. Setting the Saw. Obtain a special cir- cular saw setting stake, or get an iron disk that is % in. larger in diameter than your circular saw blade and havea slight bevel ma- MITER WITH How to Set, File, and True Up the Teeth— Pointers on the Use of Bench Machines in the Construction of a Telephone Stool By WILLIAM W. KLENKE Fig. 3. after the miters for the corners have been cut. Sawing out the groove for the spline square across every other tooth with a triangular file; then reverse and file the remaining teeth from the opposite side. Apply equal pressure on all teeth and count the strokes so as to keep all of the teeth uniform. A crosscut saw is filed at an angle of about 60° instead of 90°. After repeated filings, it becomes neces- sary to true up the teeth—that is, to make them uniform in height. This can be done by inserting the blade in the saw, bringing the teeth up until they are very slightly above the table, and then cau- chined on the top to correspond to KJ the amount of set the blade re- quires. Havea hole and slot made in thecentersothatthesawcan be revolved and also moved toward the edge. On this anvil every +. other tooth should be bent to one side as shown in Fig. 1. The blade is then turned over Fig. 2. A vise for use in sharpening can be made from two %-in. pieces of wood. tiously and carefully touching an oilstone against the saw as it revolves. This is done before the setting and filing opera- tions. The telephone stool illustrated in this article is a companion piece to the cabinet described in the preceding article in this series (P. S. M., April ’30, p. 75). Step No. 1—The Stock. On the jointer (planer) dress all stock. On the circular saw, rip the pieces to width, allowing %& in. for planing; plane to gaged depth and cut to length. Step No. 2—Top Frame. Work out the caning, slots with a groover or with the circular saw and then cut the miters for the corners. Step No. 3—Grooving for the Splines. Hold the top pieces as shown in Fig. 3 and groove for splines. Step No. 4—Turning. Care- fully turn the legs and stretchers to the design shown in Fig. 4 and sandpaper while the stock is in the lathe. Step No. 5—Cleaning Up. Sandpaper all parts smooth. Step No. 6—Assembling. Glue temporary ears on the four top- frame pieces and assemble (see P. S. M., Nov. ’29, p. 90). The and the process repeated. Filing the Saw. A circular saw vise can be made from two pieces of wood 1% in. thick, 1 in. less than the diameter of the saw blade in width, and 15 in. long. Make one end of each piece semicircular in shape and bore a hole in the center of each cir- cular end. Glue a strip of wood just a trifle thicker than the saw blade at the bottom end of one piece of the vise to keep the jaws parallel. The saw is placed between the boards as in Fig. 2 and is held in place with a bolt. If the blade is a rip saw, file pERONT. =“ Ww Fig. 4. Depuaites views of the telephone stool at a cross section of the top frame showing how the caning is held in place with a spline. (P.$ “sie view body of the stool is assembled in two operations. Assemble two legs and the correct rail and stretcher; then, when the glue is hard, complete the assembly. Step No. 7—Cleaning Up. Remove excess glue and sand- paper with No. 0 and No. 00 sandpaper. Step No. 8—Finishing. Finish the stool to match the cabinet as~suggested in the preceding article (P.S. M., April 30, p. 76). Detailed instructions for can- ing ~~ previously published . M., Aug. ’29, p. 120). M

Page 89

stone lis is pera- - this binet . this inter cular ig | and - out with Liters lines. vn in lines. ~are- chers t and is in May, 1930 POPULAR SCIENCE MONTHLY TO GIVE THE PEOPLE THE MODERN, CONVENIENT TELEPHONE SERVICE THAT THEY NEED The Bell Telephone Company... of your town An Advertisement of the American Telephone and Telegraph Company Ir Has its home in your town. Its operators are the daughters of your neighbors. Its various departments are in the hands of your own citizens, with years of training in telephone engineering and management. Who owns the Bell System? 450,000 people scattered over the United States own the stock of the American Telephone and Telegraph Company and 250,000 own other securities of the Bell System. No matter how small the part of the Bell System that serves you, it has behind it research, engineering and manufacture on a national scale. The Bell System operates through 24 companies, each designed to fit the particular area it serves—to furnish the highest standard of service in a manner personal to the needs of every user. Serving each of these 24 operating companies is the staff of the American Telephone and Tele- graph Company, which is constantly developing better methods of telephone communication. Each draws on the findings of the Bell Laboratories, one of the greatest institutions of its kind in the world, for the continual scientific improvement of telephone service. Each has the benefit of the buying power and special- ized manufacturing processes of the Western Electric Company, which supplies telephone apparatus of the highest quality and precision for the entire Bell System. Each takes advantage of every improvement in practice, equipment and economy. The Bell System’s ideal is to give all of the people of this nation the kind of modern, convenient tele- phone service that they want, over its wires to connect them one with another and with the telephones of the rest of the world. It is your telephone company, at your service with every resource that it commands.

Page 90

88 POPULAR SCIENCE MONTHLY May, 1930 Plaster-Molding Soft Metal How to Make Smooth, Perfect Castings Without Special Equipment—Pre paring the Patterns—One- and Two-Part Work— An Asbestos Mixture—Hints on Pouring By WARREN N. CRANE for molds, the process of cast- ing soft metals can be brought within the range of the average home workshop. The process is simple and inexpensive. The pattern, from which the mold is to be made, may be of almost any material that will hold its shape long enough for the plaster to “set’’; even wax or plastic (modeling) clay will serve the purpose. In the actual molding, the pattern, which should be smooth and have a good draft or taper to facilitate re- moval, is placed on a smooth flat surface such as plate glass and fas- tened with a bit of beeswax to prevent movement or “floating” when the plaster is poured on. Any undercuts should be built up with modeling wax so that the pattern will come from the mold freely, with as little hand relieving as possible. High-grade plaster of Paris or dental plaster will serve for ordinary work, but if more than one or two castings are to be made from the same mold, it is best to use half plaster and half powdered as- bestos. The table at the right shows the ap- proximate quantities required to make a mold of any given size. The figures will, of course, vary to some extent with the quality of plaster used, so it is well to take the required amount of water and add plaster (or a mixture of plaster and as- bestos) until the batch reaches the con- sistency of molasses. The figures for the plaster are useful, however, because they enable you to judge with reason- able accuracy how much to have on hand. Wherea very smooth mold is re- quired for making a number of castings, the addition of from 10 to 15 percent of flake graphite is an advantage. A form should be placed around the pattern to hold the plaster till it hard- ens. This form must be deep enough to allow the plaster to cover all high parts of the pattern by at least Bi THE use of plaster of Paris Above: A pouring gate and a venthole to allow the escape of gases and air must be cut in the mold. Right: The cast- ing as drawn from the mold. The draft on the pattern is what makes removal possible. The mold is covered on the open side with a metal or asbestos plate, which is held in place with C-clamps. VoLUME Cu. in. SOU Fe wh oe — ~ — How Much Plaster to Mix or Moto WATER PLASTER Fl. cz. Oz. Av. 42 56 84 1.12 1.26 1.68 1.68 2.24 2.08 2.80 2.52 3.36 2.94 3.82 3.36 4.48 3.76 5.04 4.16 5.60 34 in., or even more for the larger size molds. An adjustable metal form, as shown, is convenient for this purpose, be- cause any size withinits limits may be quickly set up. This type of form is also removed readily when the plas- ter has set. The mold, however, must be al- lowed to become dry and hard before any . An adjustable metal form can be made from four metal plates and as many wooden clips, attempt is made to remove the pattern. If the pattern has one flat side so that only a one-part mold is ré- quired, channels are cut in the mold for the pouring gate and air vents. A flat metal or asbestos plate is clamped against the open side so that the casting may be poured on edge as shown. If the pattern is of a more compli- cated form and requires a mold of two or more parts, the procedure is the same ex- cept that provisions must be made on the parting surface for dowel pins or other means of. keeping the pieces in register. After the pattern is removed, the part- ing surface from the impression to the edges of the mold should be given one or two coats of shellac. This prevents the parts from sticking together. When the shellac is dry, the pattern is put back in place, the dowel pins are inserted, and the form is again placed around the part of the mold already made. More plaster is now poured in to form the opposite half of the mold. When this has become dry, the pouring gate and ventholes are cut out as before, and the mold is ready to receive the metal. A few poirts to be remembered in the making of molds of this type are: First: The mold must be bone dry and should be as hot as possible before the metal is poured. This prevents the pres- ence of air bubbles and moisture and the possibility of having the hot metal spatter. Second: The pouring gate should lead to one side of the mold so that the metal runs into the cavity without turbulence. Third: The metal should be hot enough to pour freely, but should not be so hot that an excessive amount of oxide is formed. As the metal is poured, hold back the scum. NOTE: This article was scheduled orig- inally for the March issue, but was with- drawn in a last-minute change of schedule. It did, however, appear in a few of the first copies printed. In republishing it in this issue, the editor has been governed by the fact that many readers have expressed special interest in this particular subject. May, ! fr

Page 91

Id 1 t P p66 Pledge to the Public on Used Car Sales 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. 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. 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.) oe © 1928 The Studebaker Corporation of America STUDEBAKER ‘Builder of Champions POPULAR SCIENCE MONTHLY Select the car you like ... then try it out for 5 days!” “That should give me time enough to make sure I like the car.” “Yes sir. And every used car backed by the famous Studebaker Pledge carries the same privilege—five days’ driving trial!” vais oe ee ee The privilege of trial by the jury of your family—and five days to reach a verdict! That’s what the famous Studebaker Pledge permits when you choose a used car under its protection! You drive it—your wife can drive it— you Can test it in any reasonable manner for five days. Then, if you’re not satisfied, you may return it and apply your payment on amy car in your Studebaker dealer's stock — new or used! The Studebaker Pledge also provides a 30-day guarantee on all Certified cars, as well as the assured protection of plainly marked prices—one price for every buyer! More than 150,000 thrifty motorists bought Pledge-backed used cars last year. They knew that a good used car is a better buy than a cheap car bought new. INVEST 2c you may save $200 Spend 2c now for your copy of this interesting and instructive booklet, ‘How to Judgea Used Car’’—it may save youas much as $200 on the used car you buy. Mail the coupon—now! THE STUDEBAKER COP. OF AMERICA Div. 165, South Bend, Indiana Please send me copy of ““How to Judge a Used Car.” SITAR TS War gM PSE a 9 de jones ea all aed ee Soaks Saat ns r ar ~— nn ‘

Page 92

' PR ON I crak Gr a ER eS, OU HET eT re er eee pO te pre 90 POPULAR SCIENCE MONTHLY May, 1930 A Toolmaker’s 72ps on Drilling, Boring, Reaming By HECTOR J. CHAMBERLAND punch, die, and fixture work, and in the jobbing shop, boring is one of the most important—and expensive— operations. No good results can be ex- pected without the proper tools, and these must be in first-class condition. Before the details of the principal bor- ing operations in jobbing shops are taken up, the twist drill deserves a word or two. How often have you noticed two chips evenly circling out of the grooves when drilling? You didn’t have to hang on the lever of the drill press! That was because you had a drill with a correctly ground point (Fig. 3). Drill points on sizes over 34 in. should be machine-ground, ‘but that does not mean they always are. Any operator is I: MACHINE tool construction, in BORING SECTION r COUNTERBORING id SECTION SHANK PILOT — = Ne r+ s SPOT BOTH SIDES FOR HEADLESS SET SCREWS IN HOLDER ] u 5° ECCENTRIC A "6 *_ ae SHARPEN BOTH SIDES ON THIS SECTION CLEARANCE Fig. 2. Flat —-, i. tion boring tool widely LAND AFTER] used on radial drills. GRINDING~| ~ ~~~ 4 likely to touch up 4 adrill several times HIGH-SPEED hil a lil TRE while running HARDEN AND through a certain GRIND ALL A number of pieces, OVER # in most cases do- , ing the grinding free-hand. To give the drill point the cutting qualities it should have, a gage should be used. There are on the market suitable gages for this purpose, and every machinist should have one. Three things are important: the angle of point, the lip clearance, and the correct speed. Cutting lips not of uniform size will produce oversize holes and cause ex- cessive wear on the lip doing the work. Lack of clearance will throw a heavy load on the machine, split the drill, and very often cause a breakdown. Too much clearance will weaken the cutting edges, cause them to dig in suddenly, and perhaps cause injury. The wrong speed may cause almost any inconvenience. The standard drill point should have an included Fig. 3. ground drill—a preliminary guarantee of an accurate hole. Chips from a well- angle of 118°, a lip clearance of 12° or 15°, and a chisel-point angle of 130°. For drop forg- ings the approved in- cluded angle is 125°, the lip clearance 12°, and the speed 198 R.P.M.; for cast iron and machinery steel, 118°, 15°, and 387; for brass, 118°, 15°, and 540; for copper, 100°, 15°, and 540. These angles and speeds are based on the results of a series of tests that were run on one inch diameter drills. In drilling brass, stone the face of the cutting edge of the drill to reduce the angle of the spiral. When cored holes are to be drilled in casting, the operator should, of course, use a four-lip drill, if one is available. To turn from drilling to boring, there is little difference, so far as general prin- ciples are concerned, whether the work is done on the boring mill or the milling machine. With a large casting on the boring mill, the operator has to keep in mind the lining up of the bores, whether these are to be fitted with bushings for a spindle or used for stationary parts. To line up the bores successfully he depends on the line reamer. ‘Te rear bore is usually bored to size and the front bore .003 in. undersize. The job is lined up by using a bushing in the rear to fill the gap between the diam- eter of the bore and that of the reamer body. Line reamers, if made as in Fig. 4, are economical. The flutes should be made deep enough so the blades may be shimmed for any desired diameter. Fitting the blades as shown is advisable, for the reason that if the blades are given a hard drive, the entire job may be jammed when resetting is attempted. An allow- ance of .015 in. should be made for grind- ing, as for any other yeamer; this should be done cylindrically. Very often the length of the reamer is out of the range of the grinding machine; in this case the work is done on a cutter grinder as in Fig. 1. A straight arbor of the same diameter as the reamer body is mounted between the cen- ters, and the center rest adjusted. The headstock is removed and the rest is bolted at the extreme end of the table. The reamer is indexed in the usual way; the grinding is done with a cup wheel. If the reamer is first ground cylindrically, it should be relieved to with- in .005 in. of the edges; if Fig. 1. Grinding a 72-in. line reamer on an ordinary tool grinder. Reamers of this type are economical for use in jobbing shops. finished entirely on the cutter grinder, it should be made .002 in. oversize, to allow stoning .001 in. from each cutting edge. A 3° clearance angle is recommended. If the reamer is to be used for brass or bronze, the corners should be stoned to 4, in. radius. A chamfer of 30° and % in. wide is advisable on line reamers. A large proportion of radial drill work in the jobbing shop is of a special nature, and can be done economically with the combination boring tool shown in Fig. 2. These tools are made of high-speed steel flat stock with an allowance of .015 on the thickness and .020 in. on the diam- eters for grinding. After turning, a 3° clearance is filed on the ends, which come to a sharp edge; and a 5° eccentric clear- ance is filed on the diametrical dimen- ‘LOCATION OF BLADES IN RELATION TO E 6'-o" Fig. 4. Details of the line reamer illustrated in Fig. 1. Grind A .002 in. oversize, drive the blades in slots milled with a 3-in. slitting saw, and solder the blades slightly at the edges B sions. A land % in. wide should remain after grinding. When the tools have been hardened, they are surface ground. Exactly the same amount is remoyed from each side . to keep the cutting edges concentric. They are then ground cylindrically to the required sizes. To resharpen the tools, it is necessary only to surface grind .003 or .005 in. off each side, grinding lengthwise beyond the cutting sections only. To avoid wheel cracks, not more than .001-in.stock should ne removed at a time if the tool is ground dry. Suggestions on boring in the turret lathe will be given in a following article. May

Page 93

a 6 TELLING THE WORLD The Linotype tells the world what the world is doing. It forms the metal lines-of-type that print your daily paper, most books, this magazine. The Linotype is a fine-meshed thicket of deft steel arms and hands and fingers. Synchronized to a split second, they do precisely the right thing, at precisely the right moment. Because they are accurate. Accurate, in hundreds of cases, to one ten- thousandth of an inch. Accurate with the surpassing accuracy of skilled hands and precision tools—tools like Starretts. Do you work with your hands? If you do, let us urge you to use the same precision tools that make possible machines like the Linotype. With Starrett Tools, you'll do your work with nicer precision, with great- er pride and pleasure. Let us send you our new Starrett Catalog No. 25 “W”. THE L. S. STARRETT CO. World's Greatest Toolmakers Manufacturers of Hacksaws Unexcelled Steel Tapes—Standard for Accuracy ATHOL, MASS., U.S. A. POPULAR SCIENCE MONTHLY This photograph, taken through the courtesy of the Mergenthaler Linotype Company, shows the keyboard and matrix-assembling sections of the machine. Left: Starrett Micrometer No. 230, typical of the precision tools that most skilled machinists, profession- al and amateur, prefer. With 2500 other Starrett Tools, it is fully described and illustrated in the new Starrett Catalog No. 25 “W". Send for it. 50th Anniversary of Starrett Tools 1880—1930 @Orhis seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8.

Page 94

92 How to Test Brass and Bronze By W. H. HAMMOND are Muntz metal (brass), tube brass, admiralty bronze, bearing bronze, phosphor bronze, and manganese bronze. These metals do not rust as do steel and iron; nevertheless they vary widely in resistance to corrosion, hardness, and ductility. The only accurate tests to distinguish among them are chemical in nature. Since, however, these tests are simple and require only a few test tubes and no reagents that are not obtainable at any drug store, all machinists and amateur metal workers who take pride in the fine quality of their work should be familiar with them. Most foundry men define brass as an alloy of copper and zinc, and bronze as one of copper and tin with or without zinc and other metals. Tin increases the cost of the metal but tends to produce ductility without corresponding loss of hardness. - Muntz metal and tube brass contain mere traces of tin. The first is a “sixty- forty” alloy of copper and zinc; in fact, it is ordinary yellow brass. Its brittle- ness prevents its use where any great strength is required. Tube brass, which is a “seventy-thirty”’ mixture, is ductile enough to withstand a moderate degree of cold bending. To test for these two brasses, take about half a gram of drillings or filings (equivalent to a small quarter of a level teaspoonful) and dissolve in one eighth of a test tube of concentrated nitric acid, using the tube for solution. The reac- tion tends to develop considerable heat, so add the acid to the filings drop by drop, with due care for clothes and fin- IX types of brasses and bronzes are in general use by mechanics. These POPULAR SCIENCE MONTHLY gers. When the solution is com- plete, add an equal amount of warm water and let stand ‘for five or ten minutes. A clear green solution, free from white sediment (precipi- tate), indicates that the metal was a brass, because tin gives a white precipitate under these con- ditions. However, since man- ganese bronze and bearing bronze contain only a small percent of tin and so might be mistakenly classified as the much inferior brass by the result of this test alone, the experimenter should also make the special tests for these bronzes described below. O PRECIPITATE with nitric acid, on a sample which does not respond to the tests for manganese bronze or bearing bronze, practically proves the specimen to be brass. The distinction between Muntz metal and tube brass can be made by color. Tube brass is redder and more coppery in tint. For service requiring tougher, stronger, and more ductile metal than brass, the shopman should use a bronze. Admiralty bronze contains about ten percent tin and is excellent for small machine parts such as gears and valves, heavy screws and bolts, and for a better grade tubing than given by tube brass. The test for it is the nitric acid test, precisely as given for brass. Admiralty metal under these conditions gives a voluminous white precipitate. Since other less common bronzes yield a greater precipitate, it is advisable to run the test side by side with a comparative test on an equivalent amount of drillings of bona fide admiralty metal. Phosphor bronze contains about vo facing off a casting on the mill- ing machine, a fly cutter does better work than an end mill. High speeds will soon ruin a knurl- ing tool. A large needle and a ball of modeling clay (purchased at any ten-cent store) are a handy combination for setting work to fine lay-off lines on a machine. The clay can be shaped and pressed wherever needed, and the needle can be stuck in any position desired A tight belt eventually means a bad bearing. Old Bill Says— If milling cut- ters are hung on wooden pegs on the wall near a milling machine, considerable time may be saved in selecting one of the desired size and shape. When cutting a short spiral slot on centers in a milling machine, feed by hand on the dividing head and lift the end mill out of the slot at each cut. This will eliminate errors due to the backlash in the gearing. May, 1939 Phosphor bronze, when dipped in a solution of ferric chlo ride, hydrochloric acid, and water, turns dark or black, the same amount of tin as admiralty bronze, so the special “‘dip test” for the former metal, given below, should always be applied before a final decision. Bearing bronzes, sometimes called “Ajax metal,” contain between twenty and thirty percent lead and are ideally suited for heavy-duty bearings and for backing the softer Babbitt bearings. The distinguishing test for a bearing bronze is begun in the same way as the nitric acid test, except that no more acid is used than absolutely necessary. Allow any small amount of tin precipitate to settle; then carefully pour off the clear green liquid into another test tube. Add a little thirty percent sulphuric acid (oil of vitriol) and let stand for a few min- utes. A heavy white precipitate wii form if the metal was a bearing bronze. POHOSPHOR bronze is an extremely hard, durable alloy of tin, copper, and phosphorus. It stands moderate corrosion and is springlike and tough. The distinguishing test for phosphor bronze requires a special test solution: Ferric chloride, 25 grams; distilled water, 100 cc.; hydrochloric acid, 25 cc. A test piece of the metal is cleaned and dipped into this solution for exactly ten seconds. The piece is then removed and rinsed under running water. Phosphor bronze shows a film from dark to black wherever this solution touches it. The special value of manganese bronze is its property of resisting the corrosive action of sea water, acid water, and any type of saline water. The test for it is begun in the same way as the nitric acid test for brass, using one eighth of a test tube of acid. As soon as the metal is dissolved, add warm water to about three quarters the capac- ity of the tube; then,add about half a teaspoonful of dry red lead. For this test true red lead, or minium, must be used, and not the yellow pigment, or litharge. As soon as the red lead is added, ° the solution will turn dark brown and bubbles of gaseous oxygen will appear all through it. Let it stand for ten min- utes, or enough longer for the brown to: clear up and for the lead to settle com- pletely to the bottom. If the metal was manganese bronze, the clear green solu- tion will have turned to a rich purple. Se I

Page 95

or the ways wenty leally d for The ronze nitric Allow te to clear Add L (oil min- wiil onze. mely and sion phor ion: ater, test ped nds. over

POPULAR SCIENCE MONTHLY

~“

SA ee Re ee a ie PA ni RE ERS A."

Page 96

POPULAR SCIENCE MONTHLY May, 1939 | \| Mt i I yes famous test is made possible by FOSS-SET, the rock-like bristle- holding ¢ompound used only.inWooster Paint Brushes. FOSS-SET holds the bristles forever ... cannot be dis- aakohe-takel k , Ohio solved by any pa abanare THE WOOSTER BRUSH CO., Wooster _|_ FOSS: Sey Trade GUARANTEE SE IN ANYTHING ( Wooster, | Brusnes® i, OR GOOD PAINTING Ma Zz - sy, yyy yy pti a OE ci By placing the tool racks on the sides of the bench, the top is left unobstructed and free of dust-collecting recesses. woodworking bench for home and farm shops and for country schools and after much experimental work, the De- partment of Rural Engineering, Cornell University, Ithaca, N. Y., designed and built the bench illustrated, which has many noteworthy features besides its sturdiness and simplicity. Its broad top gives ample room for two workers; and, when used as a single bench, it provides that extra expanse of working space that every mechanic desires for laying out and assembling large jobs. So that the top may be kept flat and free of tool racks and other recesses for sawdust, the tools are [: AN effort to develop an improved | two } joint. By L. M. ROEHL placed in racks on both sides of the bench. As to the materials, everything needed in the construction is listed on page 96 and can be obtained at local hardware and lumber dealers, Lay out the dadoes for the lower cross braces at a distance of 6 in, from the bottom end of the legs (s:e sketch £). The joint at the upper end of the legs for the cross sill should fit flush as shown in detail drawings A and “ull |B. The two lower cross braces are next fastened in place by placing 4 by 4 in. lag screws at each Fasten the cross sills with 34 by 6% in. carriage bolts, washers, and lock nuts, as shown at B. Note that the end of the sill projects 14 in. out from the legs. The other sills are fastened by placing one 3% by 4'4 in. carriage bolt at each joint as shown in detail sketch C. lock nuts should be used here also. Place the bolt just below the bolt that holds the cross sill in place. The bottom braces that extend length- wise of the bench are fastened with two 38 wf 4% in. carriage bolts at each joint. Two ) iw 4 in. lag screws driven through the cross sill and into the end of the other sill will serve to strengthen the lower frame. For the top, 2 by 2 in. pieces of hard- wood are preferable. They are spiked together with sixteenpenny common SCREW TO >> SILL AND TOP -— INSIDE OF TOOL BOARD " J eta \ A q ® 2" SPI KED ERY 3" Assembly views of the double bench and five perspective sketches illustrating the method of assem- bling the sills and legs. Note the construction of the tool rack, file rack, and metal bench stop. @ This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. Washers and | May, ees “AC tura und nom —Fro MITTE] T the | of th all tl S} tran: resul yes, Sc wak exist is gi impr time labo

Page 97

, 1930 f the thing isted od at ilers. ower 6 in. legs f the flush int. ugh ther wer ard- iked mon May, 1930 a ee POPULAR SCIENCE MONTHLY A | we | 4% a ome (ae amg “Tlbareagy esis o % & ‘& 95 “To save time is to lengthen life—” “ACCELERATION, rather than struc- tural change, is the key to an understanding of our recent eco- nomic developments.” —From THE REPORT OF PRESIDENT Hoover’s Com- MITTEE ON Recent Economic CHANGES or PLOD of the ox-cart. The jog trot of the horse and buggy. The rush of the high-powered motor car. The zoom of the airplane. Acceleration. J’aster speed all the time. Speed and more speed in production, transportation, communication, and as a result, more wealth, more happiness, and yes, more leisure for us aii, Scientific research has been the pace- waker of this faster, yet more leisurely, ° existence, At a steadily increasing rate it is giving us hundreds of inventions and improvements which speed up work, save time and money, revolutionize life and labor in the modern age. Conceive how much time modern elec- tric lighting has saved the American people—not to mention the billion dollars a year in lighting bills saved by the repeatedly improved efficiency of the Mazpa lamp. Think of the extraordinary democratization of entertainment and education made possible by the radio tube! Both these benefits to the public owe much to the steady flow of discovery and invention from General Electric labora- tories. So do the x-ray and cathode-ray tubes, the calorizing of steel, atomic- hydrogen welding, the generation of power for home and industry at steadily lower costs. The G-E monogram is a symbol of research. Every product bearing this monogram represents to-day and will represent to-morrow the highest standard of electrical correctness and depend- ability. For tHe Home—General Electric and its associated companies manufacture a complete line of electric products including G-E Mazpa and G-E Edison Mazpa lamps, G-E refriger- ators, G-E fans, G-E vacuum cleaners, G-E wiring systems, Edison Hotpoint heating appliances, and G-E motors for other house- hold electric products. For Inpustry—Several thousand electric products and appliances, including generating and distributing apparatus, motors, electric heating apparatus, street lights, floodlights, traffic lights, airport lights, Cooper Hewitt lights, Victor X-ray apparatus, motion-picture apparatus, electric locomotives and equipment, and street-car equipment. GENERAL ELECTRIC

Page 98

Your Pipe lets you think O two ways about it—your pipe does help somehow when time comes for the brain to click along on all cylinders. Pipe-smoke shuts out the little distractions and lets you concentrate with all you have. That’s why the leaders of men, the captains of every degree, are apt to love their pipes. If you haven’t met a good pipe filled with good tobacco, now’s the time. Just be sure it’s a good pipe, for the others are not so friendly to- ward strangers. And so you can be sure it’s good tobacco too, we'd like to be there with several pipefuls of Edgeworth. See the coupon? That’s your free ticket for a generous glad- to-meet-you packet of genuine Edge- worth. All around the world you'll find it always the same — for old Edge- worth never changes. Edgeworth is a combination of good tobaccos — selected carefully and blended especially for pipe-smok- ing. Its quality and flavor never change. Buy Edgeworth anywhere in two forms — "Ready Rubbed”’and “Plug Slice.”*All sizes—15¢ pocket package to pound humidor tin. EDGEWORTH SMOKING TOBACCO potteeeee----------- eecececce LARUS & BRO. CO., 100 S. 22d St. Richmond, Va. I'll try your Edgeworth, and I'll try it in a good pipe. . My name. My street address__ And the town and state. NOW LET THE EDGEWORTH COME! K-7 4 ewe ee ee ee ee ee ee ee oe macnn aes wel POPULAR SCIENCE MONTHLY May, 1939 _ nails placed about 3 in. apart. When the required width has been built up, square a line across at each end and, with the crosscut handsaw, cut off the ends at right angles to the edge. If hardwood is used, it may be necessary to drill holes for the spikes. A 78 by 2 in. hardwood | strip is fastened to each side and a 76-in. hardwood facing piece is placed at each end after the vises have been put in place. To the inside of the sills at the top, fasten 2 by 2 in. pieces as shown in detail sketch D, using six 3-in. No. 14 screws at each sill. Leave a space of 4% in. between the 2-in. piece and the top to allow the screws to draw the top down tight. Place the top on the floor, bottom side up, set the frame on it, and fasten the top to the frame by using six 3-in. No. 14 flathead wood screws at each sill. To prevent the edges of the top from raising from the sill, an angle iron is fas- tened at the end of each sill with 34 by 11% in. lag screws as shown at F. Furring pieces 134 by 134 by 18 in. are fastened as at C to the inside of the legs with tenpenny common nails, six being driven in each piece. The tool boards are made up of two pieces and held with screws as in sketch D. Lag screws are used to hold the two If the shapes of the tools are painted on the tool racks, it is possible to tell at a glance just where each tool should be placed. rapid-acting vises jp place. A % by 13% in. by? ft. 41% in. board is ae to the side of the bot. tom brace, maki shelf on which to Bie a 14-in. jack plane, a block plane, and 4g wooden tool rack. De. tail drawing G shows how to make the tool rack. It holds the fol- lowing tools in the order written; T-bevel, 2-ft, fourfold rule, 1-, 5%. and %-in. chisels and 6 and 4-in. screw drivers, Detail H shows the con- struction of the rack for a_ half-round wood file. This rack is fastened to the edge of the leg as shown in the photograph and assembled front view. The crosscut handsaw is held by a block such as shown at J. The block is % by 7% by 5% in. and has a % by 25 in. recess cut in its inside edge. The handle end of the saw is placed on a common nail. The back saw is placed on the tool board, teeth facing up, by hanging the handle end on a nail with the head re- moved and resting the tip on a screw hook. Two tenpenny nails, placed on the right leg as shown in the photograph, form a rack for the hammer. Another ten- penny nail on the face of the left leg holds the combination try-square. When all the tools are in place, draw a line around each and paint in the shapes with black paint (see illustration above). In making the bench stop, drill two %&- in. holes 1 in. from each end of a % byl by 8 in. piece of iron and thread them with a 3%-in. tap. Fit two bolts into these holes and turn the bolts in tight to the end of their threads. Cut off the ends that project through; then cut each bolt 1 in. from the flat piece as shown in sketch J. These pegs fit into the 7%-in. holes K in the top of the bench. Curtine List 2 = ee Part 4 1% 6 O56 CCT Legs 2 1% 5% 3 4 Cross sills 2 14 5% 3 y% Sills 2 1% 3% 3a 1 End braces 2 14 3% 3 \% Braces 22 14% 1% 5 Top 2 ) 2 5 Top facing 2 w% 2 3 4 Top facing 2 1“ 1% 3 To fasten top 2 1% 13% 2 6 To fasten top 4 1% 1% 18 Furring for tool board 4 % 8 2 & Tool board 2 KB KB 5% Saw rack 2 wm A 1034 Tool rack 2 13%, 10 10 Furring be- tween vise and top 2 KR 2% 4 Rack for half- round file 2 % 13% #2 4% Shelf What Is Needed to Build a Double Workbench OrneR MarTeERIALS 4 carriage bolts (cross sills to legs) 38 by 6% in. 12 carriage bolts (braces to legs) 36 by 4¥% in. 4 machine bolts 3¢ by 2 in. for bench stops. 16 36-in. lock washers. 16 % by 4 in. lag screws to assemble frame. 16 3% by 1% lag screws for angle irons. 4 doz. 134-in. No. 10 flathead wood screws to fasten facing to tool board. 24 3-in. No. 14 flathead wood screws to fasten top to frame. 24 134-in. No. 10 flathead screws to fasten tool board. 6 1%-in. No. 9 roundhead wood screws to fasten tool rack. 24 tenpenny nails to fasten furring to legs. 12 tenpenny finishing nails for shelf. 8 lb. sixteenpenny common nails for top. 16 eightpenny nails to fasten furring. 8 corrugated fasteners for tool board. 4 4-in. angle irons to fasten top to sills. 2 pieces % by 1 by 8 in. iron for bench stops. 2 rapid-acting vises. May ey GR fe tf, EY gee ——

Page 99

May, 1930 POPULAR SCIENCE MONTHLY in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. © This seal on an advertisement

Page 100

98 POPULAR SCIENCE MONTHLY May, 1939 $5 OO2L2 Two Occasional Tables | HERMAN i aaa eae er a HJORTH Xmen vise ie | HALF PLA e smoking stands filla WS a ~, \ * co Cro tables and : aS ¢ ss genuine need _ in tile | AX every modern home. The tah | two designs illustrated on eb! this and a following page are not only attractive and sturdy, but should prove instructive projects for the craftsman in wood. The material for either of the pieces can be pur- chased for approximately three dollars—a figure far belaw the commercial J oO Nn a rrow value of such tables. The coffee table shown in Fig. 1 is a copy of an English Renaissance de- sign. This period of fur- niture dates back to the seventeenth century and | is a modified form of the | Italian Renaissance,which S ee (alias “Nuisance,” alias “English”) John Sparrow—one of the most brazen of outlaws—is sought on two major offenses. He roosts on housetops, defaces gables, ledges, windows and awn- | originated in Italy about ings, and nests in drain pipes. | 1500. To be true to the ‘ ae pol period, the table should be Ft This culprit’s open hostility | made of either white oak — i’ = drives away welcome song- or walnut. Other cabinet aoe Bhat 2 ‘aro A birds, replacing their musical woods, however, may be ios RO NT. eee ed | notes with his “cheep, cheep, | used if desired. SS es | cheep.” | _ First,two crosses should Fig. 1. Assembly views of the English Renaissance design coffee | be made, one for the base table. An octagonal inlay serves to decorate the eight-sided top. | John Sparrow should be tarred as well as feathered. Or, better still, he should be shot with a CROSMAN SILENT .22— the most amazing gun ever invented for shooting targets and killing small game, furred or feathered. Hence the $5002 REWARD for making such criminals, now at large, as silent as the Crosman Silent .22 itself, the rifle that has sixfeatures foundinno .22 firearm. For full in- formation on the Crosman Rogues’ and one to be screwed to the underside of the top. These crosses wood as indicated at the top of Fig. 2. | are of 34 by 2 in. stock and are both 22 in. While a moderate amount of time and | long. In making a cross-lap joint, find the patience is required in doing the spiral | center of both pieces and lay offonehalfof turning on the legs, anyone with an | _ the width of the pieces on each side of the average amount of woodworking ability | center lines. Square lines all around and should encounter no serious difficulties. | | place one piece on top of the other. Face- For details of this type of turning see | mark the upper side of both pieces and P.S.M., July ’29, p. 90, or the Home gage the depth of the cut from the Workshop Manual, p. 181. If desired, a | marked side of both. Cut away the waste simpler form of turning may be —_ A 34-in. tenon is turned on both ends o CENTER LINE each leg, and corresponding holes are bored in both crosses. The ornament or finial piece is placed in the center of the | base, and the four 834-in. leg braces are screwed to the base from the underside (see section AA in Fig. 2). The top can be made from glued-up | boards or from a single piece of plywood. A molding should be fitted around its | edge as suggested; and an octagonal piece | of wood of a different color and grain can - Crosman Silent. 22 Repeater eh ~~ x SHADED PARTS TO t be inlaid in the center of the top. The | rs ture of the BE CUT AWAY % - edge of the top and base may ‘ te a vate —y Ya SQUARES Th SECTIONA-A be decorated by rounding 2 u yar = e Attn il rama Nw, with sandpaper and — = | re 4 “e h Cece s GZ2EI ing a line with a marking | rosman dealer. r ie ert Eas a. 3 y ; 7 we + If made of white oak, “ CROSMAN ARMS COMPANY Ye squaRes re table aes bee a 408 St. Paul St., Rochester, N.Y. besaia ¢ =] No. 00 steel wool in order to CROSMAN RIFLES e sg {He sive certain parts, as for : | ato ee tem Fig. 2. Method of laying out a cross-lap joint; shape . example the convex parts 0 pe jILENT of rails, feet, and ornament; and rail section AA. the spiral turning and the

Page 101

f, 1930 ee | 23 Goes a ee de | May, 1930 POPULAR SCIENCE MONTHLY Makers of countless machines seek greater accuracy—precision grinding. And Norton Company, Worcester, Massachusetts, responds with grind- ing wheels made in practically unlimited combinations of bond and grain .... internal grinding wheels as small as 346” diameter... . seg- mental wheels as large as 72” diameter. GRINDING WHEELS, GRINDING and LAPPING MACHINES, ABRASIVES FOR POLISHING PULPSTONES, REFRACTORIES, POROUS PLATES, FLOOR and J STAIR TILES, ABRASIVE AGGREGATE eg Sanath berets aahoyeeineene re. tore bkeyna * magne a ao one ating a Sh UE Rie rintncniond xing TBE SEI - . me a tal teas Steen rea eR hm 2 hE i eens Ft Fecal these aay Ba ore ts s n St BN ts i 27 rere eas SEE OY Sa ae Tae Ah one cae meee =

Page 102

100 | ook fot this MILLERS FALLS TOOLS SIGN of QUALITY i when you There’s one way you can be sure of get- ting exactly what you want—look for the Millers Falls trade-mark—the sign of quality tools. You are assured of tools that will last a lifetime, that have the balance and temper for fine work. And every mechanical feature that makes work easier is yours with Millers Falls Tools—the result of 62 years of fine tool making. A Plane You'll Want to Own The 14-inch Jack Plane No. 14 is shown below. It has the famous Millers Falls cutting iron that needs less recondition- ing. It has the 3-point bearing of the lever cap that completely eliminates chatter. And notice the extra thickness and width of this lever cap. You can put almost any strain on it without fear of breakage. ; The Millers Falls line of planes is com- plete with bench planes from 7 to 24 inches, and 21 models of block planes. Ask your dealer to take one apart and show you the Millers Falls improve- ments. Send the coupon for free illus- trated folder. Millers Falls Company, Millers Falls, Mass.; New York: 28 Warren Street; Chicago: 9 So. Clinton St.; Cable Address: MILLERFALL NEW YORK. 12 Major Tool Lines Mitre Boxes Hand and Breast Drills Braces Hack Saw Blades Hack Saw Frames Automatic Tools Levels Automobile Jacks Planes Nail Sets and Punches Bit Extensions Auger Bits and xpansive Bits MILLERS FALLS TOOLS Mititers Fauis Company, Millers Falls, Mass. Send free illustrated folder on planes. it ho iG, © Wiu.w-a srk hie pe enin'e Caen edb * buy deci POPULAR SCIENCE MONTHLY May, 1930 edges of the top, the ap- pearance of wear. It should then be given a coat of paste wood filler, thinned with turpentine to the consistency of cream, which can be ap- plied with a brush. When the surface loses its luster, rub it across the grain with a piece of cotton waste to force the filler into the pores of the wood. Wipe the surface clean and allow it to dry for at least 24 hours. The table next should be given a coat of shellac, which is rubbed down with steel wool when it dries. Then it can be polished with paste or liquid furniture wax. The modernistic smok- ing table illustrated in Fig. 3 consists of ten sim- ply constructed pieces— four legs, four feet, a shelf, and a top. On each end of each leg a 1 in. diameter tenon % in. long is turned. Inside this a 134 in. diameter shoulder is formed, the top shoulder being 34 in. and the bottom one 114 in. in length. For details re- ' garding the process of reeding see P.S.M.., July ’29, p. 90, or the Home Workshop | Manual, p. 179. The top and shelf are made of boards at least 114 in. thick and planed down to a uniform thickness of 1 in. It is best to plane across the grain of the wood until the surface is flat. Test repeatedly with a steel square, placing the square not only straight across the board, but also diagonally from corner to corner. Finish by planing and scraping along the grain. Gage the thickness on the sides and ends of the boards and plane the other surface to the desired thickness. The top and shelf pieces may also be made by gluing several layers of plywood together. This is easier because no plan- ing is necessary, only scraping and sand- ing. The layers should be clamped to a flat surface while the glue is drying. The circular outline of the boards is marked as follows: Drive two brads, 12 in. apart, through a small stick of wood. Fig. 3. Any attractive, close-grained wood can be used in the construction of this modernistic smoking stand or coffee table. Bill of Materials No. 0 yy Part - =« *£ For Corree TABLE 4 Legs 1% 1% 223% 4 Crosses 3% = 22 + Feet 1 1% 3 4 Base % 3 834 1 Finial 1 1 3 1 Top 38 27 27 1 Molding % 1 96 For SMOKING STAND 4 Legs 24% 2% 2 4 Feet 24 2% 4% 2 Top and shelf 1 24 24 Place one of the small points in the center of the board and mark the circle with the other by revolving the stick. Saw out and finish the edge by sanding it on a disk mounted on a faceplate (see P.S.M., July ’29, p. 124). A disk sander of this type is useful and very easy to make. Turna disk of soft wood such as white pine or cypress about 2 in. thick and of as large diameter as the lathe will swing. Face it off so that it is perfectly level and smooth, and gluea piece of No. 114 sandpaper to it. When dry, trim off the edges of the sandpaper and screw the faceplate on the live spindle. Lay out the centers for the tenon holes in top and shelf, and bore them halfway through the wood. Bore small holes (about %-in.) in the center of the 1-in. holes through the shelf, but do not bore through the top. These serve as centers for the 54-in. holes to be bored for the turned feet. Glue the four legs, the top, and the shelf together, being sure to place the top and the shelf so that all of the grain runs in the same direction. Turn the four feet according to the drawing, bore the 54-in. holes, and glue the feet in place. If the stand is made of maple, birch, or a similar light-colored wood, a striking effect may be produced by painting the edges of the top and shelf, as well as the shoulders above and below the reeding, with black lacquer. This is especially desirable if the top and shelf are made from several layers of plywood. The surface as well as the reeding should be given a coat of white shellac thinned with alcohol. This should then be rubbed down with No. 00 steel wool, after which one or two coats of clear lacquer should be applied. The lacquer may be rubbed down with No. 5/0 waterproof sandpaper. ® This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. MA Th str bla per wit for Di: A fin too cel

Page 103

1930 ————— ter the ind isk uly 2 is isk ess ter iat ea en yer le. les ay les in. re ers he he op ns et in. or ng he he 8, de ld n be ad Tr. May, 1930 POPULAR SCIENCE MONTHLY 101 Amazing New Hack Saw Blade of Disston High-Speed Steel Cuts Hard Metals that defy ordinary blades rs) Lasts 6 times as long; cuts easier, faster, better OW Disston brings you hack saw blades, for use in your hand frame, made of the same steel, with the same cutting stamina, as the Disston High-Speed Steel Machine Hack Saw Blades which, in actual tests, have outlasted fifty or more alloy- steel blades, cutting twice as fast, and cutting, with ease, steel that no other blades could touch! Every man who ever uses a hand hack saw will Use the Right Hack Saw Frame The Disston No. 3614, illustrated, is extra strong, to hold blade firmly. Takes 8” to 12” blades. Handle, of hand saw type, gives user perfect control of saw. Frame nickel plated, with riveted sockets and reversible stretchers for sawing straight or sidewide. $2.10. Files for the Metal Worker Every kind, size and style, all made of Disston steel. Accurately cut, dependable. A Disston 8-inch Mill File, bastard cut, is fine for sharpening axes, lawn mowers, garden tools, and general work in home and shop. Ex- cellent for finishing metal surfaces. 25 cents. N using a Disston High-Speed Steel Hack Saw Blade in a hand frame, see that material to be cut is held firmly. Stretch blade tightly in frame, with teeth pointing forward. Start cut easily with a light forward stroke, as in filing, and lift blade slightly on return stroke, to prevent teeth from rubbing in the cut. Put pressure on each forward stroke by moving body back and forth in line with the stroke instead of moving hands only. Make each stroke do its work. Forty to 60 strokes per minute, want these faster, harder, tougher blades of Disston High-Speed Steel: money savers, labor savers. To make it easy for you to try them, we will mail you a Disston High-Speed Steel Blade, 10-inch length, 18 teeth to inch (standard for all-around use) for 30 cents; and, with it, the new Disston Hack Saw Chart. Just send the coupon below, and later buy at your dealer’s. Cut it with Disston Steel, in saws, tools and files! “’TheSaw MostCarpenters Use” The two handiest saws for the home work shop are the 26-inch 8-point for cross-cutting, and the 26-inch 5!4-point for ripping. You will need these on almost every job. The pular “D-8” Lightweights cost $3.45, Many other styles and sizes to choose from, HighSpect Steel Hack For Cutting Soft Metals Saw Blades by their You can use a Disston Metal-Slitting Saw on ORANGE BAND and your power outfit. Cuts sheet brass, zinc, the Disston name. ‘‘hese blades are madeinall copper, etc. Disston makes the most efficient sizes for hand and machine use.- They give ~aa-cnties circular saws of all types. results never before obtained in metal cutting. Write for infor: or information and prices on Disston Metal Cutting Saws for any purpose. with pressure, will cut faster, more accurately, and easier than faster strokes without sufficient pressure. “The Disston Hack Saw Chart”’ is a new and valuable guide to tool users, amateur anu professional. It tells and shows how to choose and use hack saws for every purpose. A copy of this helpful chart will be included, without charge, with your order for one Disston 10-inch High-Speed Steel Hack Saw Blade for 30 cents. The coupon below is for your con- venience. Use it now, before you forget! DISSTON Makers of “THE SAW MOST CARPENTERS USE” For only 80 cents, in coin or stamps, (40c in Canada), Disston will send you, promptly, post-paid, the amazing new Disston High-S Steel Hand Hack Saw Blade, in the 10-inch size, Henry Disston & Sons, Inc., Philadelphia, U.S. A. (In Canada, address Henry Disston & Sons, Ltd., Toronto) For 30 cents, enclosed, (in Canada, 40c), send Disston High Speed 18 teeth to the inch, and with it “The Disston Hack Saw Ae oe EE os oT da, § Chart,” which embodies the latest information on the use of Ble ee Ba ee Steel Hack Saw Blade and “Disston Hack Saw Chart hack saws. Mail the coupon, and buy later from your dealer. Ey Sor arate ame 0068. A000 vis 160s sien uriasinmmnitanuiimnvbiesimnnatcnaiaam © This seal on an advrtisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8.

Page 104

102 POPULAR SCIENCE the train doesn’t even stop for water Sustained speed || | on rails—sixty , .\ miles an hour \, for ten hours —to make its run on the time table’s time. The engineer must have sus- tained runnin speed—the nce in the shops, sustained filing speed—therefore chooses Nicholson Files. Railroad men, like almost every- one else, pick their files for per- formance when used by hand. Nicholson Files are made for hand use. Test them for your- self at home or in the shop. At your hardware or mill supply dealer’s NICHOLSON FILE COMPANY Providence, R.1., U.S.A. Ol se U.S.A. (TRADE MARK) A File for Every Purpose MONTHLY May, 1939 © This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. Stagecoach Model Making Sweeps the Country be THE few months since Poputar SCIENCE MONTHLY introduced the new hobby of stagecoach model making with a series of articles on the construction of the now famous Diamond Tally-Ho, the vogue for decorative models of this type has swept from coast to coast. Among the first to realize the popu- larity of coach models were the depart- ment stores. One of the largest and most exclusive stores in New York hastily gathered a collection and put it on ex- hibition. Not only the general public, but interior decorators, magazine and newspaper feature writers, and buyers from other stores visited the exhibition. So great was the demand for replicas of the models, that arrangements had to be Model of the Diamond Tally-Ho built by Ed- win M.Love. It is 10 by 13 by 20 in. over all. made for their manufacture on a produc- tion basis. Writing of this exhibition in the New York Times, Walter Rendell Storey, a specialist on interior decoration, made this comment: “Ship models, which have long been useful accents in certain types of interiors, now have a rival in the models of stage- coaches. This decorative touch seems a logical development, for models of stage- coaches are obviously a complement to the frigates and old-time clippers of the ship model maker. Perhaps soon we will have stagecoach model clubs where amateur model makers, like the makers i D0 QS of miniature ships, will compete with one | another in bringing back to us famous and | picturesque models of early vehicles of | transportation. Suggestions of old coach- | | ing days, long a subject for prints and | other forms of pictures, may now be re- called through miniature models on the hearth mantel or may adorn the top of | a desk.” What Mr. Storey says is borne out | by the enthusiasm with which readers | greeted the stagecoach articles in our February, March, and April issues and by the demand for PopuLAaR SCIENCE MonrTHLY Blueprints Nos. 115, 116, and 117, which give full size drawings of the stagecoach illustrated (see page 111). Next in the PopuLAR SCIENCE MONTHLY stagecoach series is to be a scale model ee

Page 105

May, 1930 POPULAR SCIENCE MONTHLY 103 THE METAL THAT. LES: “TUNED TO RADIG Look for Aluminum Shields Around Tubes—Coils—Condensers Look for Alcoa Aluminum shielding in the highest electrical conductivity of any the radio you buy and you will see of the metals used in set building. In another reason why your new radio will addition, it is extremely light, thereby be clearer, better toned with less diss __ reducing the weight on supports and i tortion. materially lessening the possibility of 1 the set being thrown out of perfect ad- Because of the tremendous amplifyin Pian justment by rough handling in shipment. power of the screen grid tube—the lat- est developments in band pass circuits, tt Hiith, 3 Alcoa Aluminum, used for shielding, for the selectivity and sensitivity you de- foil’ condensers, for variable condenser blades, for wire, panel, chassis, and other parts, makes a good set better. Ask your dealer where Alcoa Aluminum is used in the set you are considering. It is your assurance that the manufacturer has selected high quality materials. | Alcoa Aluminum is an excellent con- ALUMINUM COMPANY of AMERICA; i ! mand in your set today are not possible without effective shields. This is the reason why so many manufacturers are now standardizing on Alcoa Aluminum with its well-known combined electrical and physical properties. ductor. In fact, it has, weight for weight, ALCS 2496 Oliver Building, PITTSBURGH, PA. ALCOA ALUMINUM a

Page 106

POPULAR SCIENCE MONTHLY May, 1930 1 WISH BOB WERE HERE WITH HIS HARMONICA! MAYBE HE ISN'T COMING! - ~ | HOPE HE % 0 COME OR THIS PARTY WILL BE A FLOP HERE! ; OULDN’T you like to be able to play the harmonica so well that you could make your crowd sit up and take notice like Bob and Ann do? Wouldn’t you always like to be in demand at parties—always “in” on all the good times? WELL, HERE’S YOUR CHANCE! Without costing you a cent, you can learn to play the harmonica almost like ‘a pro- fessional in a short time. Just send the coupon below for the FREE Illustrated Instruction Book, “HOW TO PLAY THE HARMONICA.” You don’t have to know one note from another to begin, for this book tells you just what to do and illustrates each easy step. In afew minutes youcan play the scale and the simple melodies shown in the book. And soon you'll be amazing your friends with the way you can reel off popular airs. “I never had a music lesson in my life,” says twelve-year-old Bob Lewis from Ohio. “I did not know one musical note from another—but now I play any song, popu- lar, classic or jazz, I have ever heard, and eee and I are very popular.” veryone loves the harmonica, and you can always have it with you, no matter where you go. Hohner “MARINE BAND Are You the Popular Boy in Your Crowd? John Philip Sousa, the famous band- master says, “I am a great advocate of the harmonica and especially endorse the harmonica bands.” 7 In thousands of schools and camps har- monica bands are being formed. A special booklet giving full directions will be sent free to those in authority. A QUALITY INSTRUMENT Hohner Harmonicas are the choice of pro- fessionals everywhere. Musicians recognize them as the “‘world’s best’’; real musical instruments.true in tone, accurate in pitch, —_ in workmanship. While Muhasr armonicas are slightly higher in price than inferior instruments, you always have the satisfaction of knowing you own the best—one thatenables you toplay anything from jazz to opera. Learn to ten a Hohner. Fill out coupon now and mail it AT ONCE. You can get Hohner Harmonicas everywhere, in many different styles—at all prices. FRE Mail Coupon TODAY See how easy itis to play Illustrated Harmonica Instruction Book -s- eo eo ESE EEE eee ee a M. HOHNER, Inc., 114 East 16th St. Dept. 19E, New York _ Please send me at once FREE Illustrated Instruc- tion Book which tells me how to play the harmonica. the ideal instrument for thel! Name beginner, vy ay ey almost} — octaves in the diatonic Address | of a covered wagon now in the Pony Ex. | press Museum at Pasadena, Calif. The | first installment will appear in the June | issue. | time to build a prairie schooner model, for | this year is the centennial of the covered | portance that President Hoover recently | them with anything but high-grade wire | insect screening. ——— There never was a more appropriate wagon. The first wagon train left St. Louis, Mo., for the long and hazardous trip to the Oregon country on April 10, 1830. This was an event of such historic im- The covered wagon model to be described in the following issue of PopuLar SCIENCE MONTHLY. issued a formal proclamation asking the Nation to observe the period from April 10 to the end of the year as the “Covered Wagon Centennial,” and in so doing to “recall the national significance of this centenary of the great westward tide which established American civilization across a continent.” Because of the many novels and motion pictures which have portrayed vividly the pioneer life of the West, the covered wagon has become a symbol of that great period in American history. What could be more appropriate than to build a model of one of these picturesque old vehicles to serve alike as an ornament and as a reminder of the heroic days of the Santa Fé and Oregon trails? Hints on Making Screens O LAY out window screens, the safest way is to make a measuring rod from a light strip of wood. Cut it the exact length of the screen and mark on it the exact width; or, better still, cut a second piece to represent the width. The stock should be approximately 1% or 74 in. thick by 1% or 2 in. wide for the stiles and cross rails; and 1% or 78 by 2% or 3 in. for the bottom rails of all except the smallest screens. These dimensions are not hard and fast; your lumber dealer will have in stock suitable material for making screens and will know what is customarily used by the carpenters in your own neighborhood. Figure the number of lineal feet nec- essary and get the same number of feet of screen molding, which js used to cover the raw edges of the screen cloth. Your lumber dealer may have a special screen molding for this one purpose, or he may give you 1%4-, 54-, or 34-in. half-round molding, which is often used and will be quite satisfactory. Naturally, after going to the pains of making good_screen frames, a home worker would be shortsighted to cover ——

Page 107

he ril ed ris de on on ly a Id nd he st ct he ad yg he 4 pt ns er or in of er ur Ly id be of 1e er Hee talking pictures that sound NATURAL .... 22 theatres which show this sign Nowadays it is not enough for a theatre to give you the best talking pictures. It must reproduce dialogue and other sound with utmost clearness—in short, it must pass your EAR TEST. Go to theatres equipped by Western Electric and you make sure of ear entertain- ment. This apparatus gives its satisfying Wester. SOUND POPULAR SCIENCE MONTHLY Select your theatre ACTION results because it was made by the world’s leading experts in Sound transmission, the makers of your telephone. Look for the Western Eleetric sign in the lobby. Enjoy the voices of your fa- vorite stars reproduced with full justice to their personality and art. Hear talking pic- tures at their best. Electric SYSTEM if we ee oe = Peete We SSB ree " ms SS 7 Ne ee ae ae ee o SEe ee Seen neni aaa . a = hh m ty maar) wa Sty. - . 5 “ ; os BY THE MAKERS OF YOUR TELEPHONE

Page 108

106 ® Fix it with a MAYDOLE Users of good tools know from experience that for doing any one of the hundred odd jobs of ‘‘fix- ing”’ around the house or garage, there isn’t a better hammer than a Maydole. Strong, sturdy, carefully bal- anced, won’t tire the muscles in your hand or arm these Maydole Hammers are built from high grade tool steel and selected sec- ond-growth hickory. Your dealer carries them, ask him to show you the weight you like. Please send a free copy of Pocket Handbook 23B containing many val- uable tables and much useful infor- mation. May Youn HAMM. f ole a. The David Maydole Hammer Co., Norwich, N. Y. ee POPULAR SCIENCE MONTHLY May, 1930 Skillful staining or painting wiil bring an old mantel into harmony with any modern color scheme. ' uniform color tone. | ing over the entire surface so that the New Finishes for Brickwork. Stains and Dyes—Glazed, Shaded, and Plastic Effects—Cold Water Paints By BERTON ELLIOT IREPLACES, mantels, chimneys, Piss: interior brick surfaces may be modernized in various ways to har- monize with new decorative schemes. The old notion that brickwork must remain always the same in appearance has been dispelled. Indeed, bricks can be finished in practically any shade or tint desired without destroying the characteristic tex- ture that gives them their charm. One of the simplest methods is to treat brickwork with ordinary shingle stain. This soaks in without producing a glossy film over the surface. Where the brick is neatly pointed with white, black, or col- ored mortar, the stain may be applied carefully with a small brush to one brick at a time so that it will not run over the mortar joints. The standard shingle stain colors should be reduced with kerosene or naphtha to the desired tint, care being taken not to have the mixture too strong to start with. It is easy to increase the intensity of the tone, but if too deep a stain is once ap- plied to the surface, it cannot be lightened. If a few bricks can be obtained similar to those you desire to finish, try the stain on them, experimenting until you obtain the right effect. In applying the stain, no attempt need be made to bring the different bricks to a Apply an even coat- | individual bricks will retain their indi- vidual depth of hue. This gives a rather pleasing mottled effect characteristic of brickwork. Another method is to color the bricks with water soluble aniline stains, which come in powder form and are sold by the larger paint supply stores. They are dis- solved in hot water in proportions to give the strength of color desired. Such colors as brown mahogany, walnut, red mahog- any, and Bismarck brown are suitable for the coloring of brick, according to the effect desired. The brickwork should be washed with water immediately before applying the stain. Aniline stains, like shingle stains, will color the bricks with- out filling up the depressions or changing the natural texture of the surface. If the bricks are too dark in color to be changed to a desired lighter effect, they may be painted with a suitable founda- tion or background color, over which a semitransparent glaze coat is applied, and wiped off as desired. The background color is generally flat wall paint or other flat drying paint. Ivory, buff, and light shades of green, blue, and gray are the colors most ex- tensively used. Two or three coats should be applied, depending upon how porous the bricks are. The first coat should be thinned with a generous amount of lin- seed oil and a little turpentine to satisfy the absorption demand of the brick. When the foundation has become thoroughly dry, the glazing may be done with oil colors and glazing liquid in the same way as the familiar “Tiffany” blending on walls. Oil wood stains are often used for glazing instead of oil colors. When the glazing method is used, the foundation color is generally applied over the entire surface without any attempt to keep it from getting on the mortar joints. It may, therefore, be sprayed if a hand or electric sprayer is available. Indeed, @® This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. MA f | S FI fm OL OL 8d OE eS”

Page 109

1930 is- ve rs g- or he be re May, 1930 those who understand the use of a spray gun can spray on the glaze stain coat in shaded or stippled effects, similar to those used in the decoration of painted furni- ture. DECORATING fireplaces, plas- tic paint sometimes can be used to advantage, especially over surfaces in poor condition. It can be applied to wood and tile fireplaces, as well as brick. With its aid old-fashioned fireplaces or mantels may be transformed; and if it happens that there is too large an area of exposed brick in a room, it may be blotted out. The plastic paint is brushed on in an un- broken coating and is then usually stippled to produce a pebbled or rough textured effect, or modeled into relief designs. The manufacturers supply full directions. When the finish has hardened, it may be given a glaze, polychrome, two-tone, or any other color treatment desired. Basement walls form another class of interior brick surfaces. They do not re- quire the more delicate treatments just described, except in the case of lounging or billiard rooms. With basement walls the requirements are economy, neatness of appearance, and serviceability under more or less hard wear. Brickwork in a basement (or, for that matter, anywhere else) should never be painted immediately after the brick is laid. It always hasa certain lime content, which will tend to burn the paint as long as the lime remains active. On inside surfaces, however, the lime usually “cools off” within two months, when the bricks ordinarily can be painted without danger. Another point, quite as important, is that the walls must be thoroughly dry. Moisture, if present, will prevent satis- factory painting. Be sure the brick is dry all the way through; not merely sur- face dry—especially soft brick. EMEMBER, too, that plenty of oil should be used in the priming coat, as bricks drink in the oil greedily. The softer the brick, the more oil should be used. Not less than three coats should be ap- plied for assurance of a good job. The priming coat, when thinned liberally with oil, has very little hiding power, and two more full coats are needed to produce a good finish. In giving brickwork a plain painted fin- ish, it should be remembered that regular house paint—in fact most oil paints— produce a gloss finish, but special con- crete wall paints are available which dry with a flat or dull finish, where this is preferred. Gloss paints, however, are durable and withstand water that is splashed about in mopping floors and using the laundry tubs. Another material especially adapted for use on basement walls—not only brick but cement, concrete, stone, and wood— is cold water paint, a dry powder, similar in appearance to kalsomine, but made with a casein binder instead of ordinary glue. The casein is insoluble in water and does not run. After being wet, the paint dries out to a smooth, even surface. Be- Cause it can withstand water, cold water paint is a practical and economical ma- terial for use on basement walls and partitions. POPULAR SCIENCE MONTHLY 107 Photograph of the mae ual tests by rts given to Yankee" Drill- points—each and every one. ld you get tested drill-points N THE handle of the ‘“*Yankee’’ Automatic Push Drill you find a full set of eight mua geiete for Every man who uses a screw-driver has need for a tool to make holes for the screws he drives. ain holes from ;s up to Like every “Yankee” 21 inches: Tool for its particular job, ALSO—you find each the “Yankee” Automatic Push Drill will do its job— with large drills or small, in hard wood or soft—better than any other tool. Holes bored in hard or soft wood without splitting. Drill-point is revolved by pressing on handle; spring brings handle back for next push. The name “ Yankee” is a guarantee of quality in a tool. Look for ‘ Yankee” when you buy a push drill. drill-point stamped with the name “ YANKEE.” That means that every drill-point—in the very tool you get, has been in- dividually tested by “‘Yan- kee” tool-makers. It means that each drill-point, from the smallest to the largest, is right in temper and best suited for speed and effi- ciency in the work for which it is intended. **Yankee’’ No. 41 **Yankee’’ No. 44 Automatic push drill used by mechanics every- where as the worki mate of the “Yankee’ Spiral Screw-driver. Price, $2.60 Automatic push drill with adjustable ten- sion, to regulate pres- sure to suit kind of wood, a} Xn drill, etc. Price, $3.1 "YANKEE * TOOLS > 3: Ph sina — 7 \—---------TO HELP YOU MAKE THINGS---------— North Bros. Mfg. Co., Lehigh Avenue, Philadelphia, U. S.A. My idea is to save time and labor. Send me “Yankee” Tool Book, with action neares showing new Two-speed (11-inch) Hand Drills, new Bit Braces with famous “Yankee Ratchet, Quick-Return Spiral Screw-drivers, Adjustable Tension Push Drills, Ratchet Breast, Hand and Chain Drills, Automatic Bench Drills, Ratchet Tap Wrenches, Re- movable-base Vi ises, etc. COR eee eee OEE HH EEE HEHEHE EHH ETH E EEE EEE © This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8.

Page 110

108 © A. S. R. C. 1930 close harmony Your skin rejoices, you burst into | song—so swiftly, comfortably, completely does your beard depart at the soothing touch of the Ever- Ready! This super-keen blade is so durable it gives you many more shaves than the blade you are using. Join the chorus of Singing | Shavers—-buy Ever-Ready Blades. Product of American Safety Razor Corp | Ever-Ready BLADES

POPULAR SCIENCE MONTHLY

May, 1930

Wiring a Small Garage

By HAROLD P. STRAND

CUT OUT CABINET CONNECTORS SEPARATE CABINET

= \ }] ai Zo, —|F 4 ESJESSSsSs 3-WIRE BX thf ) x a | s/f | \t \\Y \ CLIPS JUNCTION BOX” \J] ia ° AZ oll ATS aw 2 am 2-WIRE BX x | HOUSE CIRCUITS BX FROM : I | 2 GARAGE ]||| 3"JUNCTION BOX w if FOR SINGLE-POLE a | : ) SWITCH oF 4 , z ( a) @ | i) r FROM " —; | METER S CUT OUT me H CABINET © 5} ; L é | t 5 Sd g l— HU fs w FUSES . S'JUNCTION BOX “ res - FIG.4 FOR DOUBLE- Vf NU 9 eS Xf = A_3} POLE SWITCH ee hn ; cael nae qa Ve" CONDUIT FROM HOUSE z Sketch showing arrangement of flexible armored cable wiring system for a two-car garage. drill or with hammer and chisel. Place the 14-in. conduit in the ditch and al- low it to project into the cellar of the house and up into the interior of the garage as illustrated below (Fig. 1). Since the conduit comes in 10-ft. sec- tions, it will be necessary to join sev-

The two methods which can be used in in- stalling the additional cut-out or fuse block. IRING a garage should not be a difficult problem for any mechani- cally minded man if he will observe the few general hints which follow and will take the time to learn the wiring re- quirements of the building code in the locality in which he lives. In some places there are special rules governing the application of wire to an outside building; therefore it pays to con- sult the local authorities before the work is started. If no special rules exist, the work can be carried out in the way to be described. Upon the completion of the work, however, be sure to have the local electrical inspector look it over to see that it conforms to the wiring codes and specifications. E Simplest of all wiring methods is that employing flexible BX cable. The only tools needed are a hammer, screw driver, pliers, sharp knife, hack saw, and solder- ing copper or blowtorch. BX is easy to work and can be applied to buildings con- structed wholly of wood or to those made of cement block. brick, or stone if they have a wooden roof. The ditch for the feed line—about 1 ft. | wide and 1 ft. deep—should run as di- rectly as possible from the house to the garage. ‘This line may be strung over-. head, but it detracts from the appearance of the house and may be damaged by storms. At each end of the trench knock a 2-in. hole through the foundations with a stone eral pieces to get the required length. Fasten a 3-in. octagon junction box at the garage end of the conduit as indicated in Fig. 1. Secure the box to the woodwork; or, if none exists, to a 4-in. wide board set upright between floor and roof timbers. At the house end of the pipe another 3-in. junction box is fitted, this time the entry being made from the back of the box. Measure the length of the conduit and cut No. 14 twin-wire leau-covered cable about 1 ft. longer. With the aid of

COMPRESSION SCREW Se

FIG.2 : S < V/) / KNOCK-OUT a o) 4A\ DISKS BX BOX ¥ CONNECTOR 4 nen | X 8 x< a

NO 14 LEAD TWIN GARAGE Wire IN PIPE JOINTS SOLDERED AND TAPED FIG.1 HOUSE CELLAR The feed line, the 3-in. junction box at the garage end, and a BX box squeeze connector.

— -—- «ob -™ =e 45 ~ FOO Tre «A an aeees ff 2h Gh 2 a) ao. i lh al

ieee ap

Page 111

, 1930 OD LLL | gullies y --— “a ace ev- ‘Nw May, 1930 a stiff steel fish wire, pass the cable through the pipe. The feed is continued from the box on the wall of the basement to the fuse box with No. 14-2 cable. A squeeze connec- tor should be used where the cable leaves the junction box. Join the wires at the junction box color to color (see Figs. 1, 2, and 3). Test the various circuits in the fuse box for a lightly loaded line. If none exists, a separate cut-out block will have to be installed; and if the fuse box is already crowded, it will be necessary to install JUNCTION BOX “FROM LINE TO LIGHTS AND PLUG ON WALL FIG.S AS DO se CABLE : -" —— 25 on ATTACHES HERE FIG.7 The three-way junction box (Fig. 5); how the fixtures are installed (Fig. 6); and wiring plans for the two droplight junction boxes (Fig. 7). another fuse cabinet (see Fig. 3). grounded side of the fuse block. The wiring in the garage is carried through entirely in BX. At the junction box at the end of the conduit lead from the house, a double-pole switch is placed. This will serve to cut out the entire cir- cuit if it is necessary to do so in order to repair the system. The No. 14-2 BX cable is carried up and across the wall to a three-way junc- tion box above the switch for the lights (see Fig. 4). A diagram of the wiring for this junction box is shown in Fig. 5. The two-wire cable at the lower edge of the box goes down to the single-pole switch. Three-wire cable is used from the three- way junction box above the switch to the first light box (see Fig. 6). Wire the fix- ture in the manner shown, connecting the wires color to color. A three-wire cable runs from this box to the second light box, and the connections there are made as in Fig. 7. The two wires in the receptacle line are connected color to color to the black and white wires in the three-wire cable that comes from the first light fixture box. Study Figs. 5, 6, and 7 carefully before doing this part of the work. A word as to the attachment of the ground for this system. If the wiring in the house is BX or metal conduit and if metal boxes are used, the system will be grounded through the metal. If, how- ever, open wiring is used in the house, it will be necessary to supply the new cir- cuit with a suitable ground by putting a The | white BX wire should be attached to the | POPULAR SCIENCE MONTHLY 109 / Shaves & FREE “i to dissatisfied shavers Here is good news. Five unique features have won 86% of the men who try this remarkable shaving cream. A test offered, free. ENTLEMEN: A free trial test is the method we've employed to in- troduce Palmolive Shaving Cream. For if it is all we claim, we win new users to it. 86% of the men who have tried Palmolive Shaving Cream abandon all other methods for it—tell their friends —make claims you might doubt if we printed them. For 67 years we have been making “leaders” in the soap field. Thus it is natural that our laboratories would not rest content until our shaving cream was worthy to join that group. 129 times they rejected their own formulas. The 130th time they were successful. Their idea was to make a shaving cream in which olive oil would play a prominent part in easing the ac- tion of the blade. Five great advan- tages resulc. 5 Features 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 shaving. 5. Fine after-effects due to palm and olive oil content. Are they what you are seck- ing? Then won't you make our test? The responsibility is ours. We undertake to win you, in 7 test shaves. A fair trial, we be- lieve, will do it. So won't you mail the coupon, please? ccdbasenendsthanenanteenebastinin ébthenas —— ee SHAVES FREE and a canof Palmolive After Shaving Talc Simply insert your name and address and mail to Palmolive, Dept. M-827, P, O. Box 375, Grand Central Post Office, New York City. PALMOLIVE RADIO HOUR-Broadcast every Wednesday—from 9:30 to 10:30 p. m., Eastern time; 8:30 to 9:30 p. m., Central time; 7:30 to 8:30 p. m., Mountain time; 6:30 to 7:30 p. m., Pacific Coast time—over WEAF and 39 stations associated with The National Broadcasting Company. $257 Mo ll De ee ae oe oe es oe oe ee oe oe ee?

Page 112

110 POPULAR SCIENCE MONTHLY “45° Twin One of the 1930 models, Harley-Davidson price range from $260, f. o. b. factory. AMUSEMENT PARK LL yours with a Harley-Davidson Motorcycle—the dip and zoom of the “Roller Coaster”, the thrilling whirl of the “Airships”, the zip and speed of the “Whip”! All yours to enjoy — every time you ride your Harley-Davidson — for motorcycling combines the thrills of a dozen sports in one. You never tire of it. What wonderful vacation and outing trips you'll take with the jolly bunch of Harley- Davidson riders! And the cost is so lobw— a Harley-Davidson is easy to buy, and its upkeep is only a penny or two per mile. Let your nearest Harley-Davidson Dealer show you the 1930 models, and se explain his Pay-As-You-Ride Plan. Mail the coupon to us for literature. qte° HARLEY- DAVIDSON Mail the Coupon / HARLEY-DAVIDSON MOTOR CO., Dept. P. S., Milwaukee, Wis. Interested in your motorcycles. Send literature. Name Address. My age is [) 16-19 years, (] 20-30 years, [1] 31 years and up, [J under 16 years. Check your age group. May, 1939 | ground clamp on the BX cable and run- | ning a piece of No. 10 rubber covered wire | from this to a similar clamp placed on a | water pipe. Extracts from important sections of the National Electrical Code which concern the wiring operations required for this installation are as follows: Sec. 3302. Cut-outs, switches, attachment plug receptacles, and lamp holding devices shall be located at least 4 ft. from the floor. Sec. 3303. Approved portable cord suitable for hard use shall be used to connect all port- able lamps, motors, and appliances. One end of the portable cord shall be equipped with a | male end pin plug and the other end shall have a handle, socket hook, and guard fastened to the handle. Sec. 503. Conduit shall be installed as a complete system without wires and shall be | connected to all boxes and fittings both elec- | trically and mechanically. The ends of the | conduit shall be reamed to remove all rough | edges and there shall be no splices or joints | within the conduit proper. All joints shall be made mechanically and electrically tight with- out solder, and then they shall be soldered, compounded, and taped equal to the original insulation on the wire. If first-class materials are used and the | work is carefully done, the wiring is reasonably certain to pass inspection. Shop Storage Tray Simplifies Selection of Odd Parts [% ALMOST every home shop there are | cans and boxes filled with bolts, nuts, and odd parts. Looking for just what you | want is a tiresome task, but it can be | made easier by the method shown below. | A framework of 34 by 2 in. strips is | built to fit between the studding back of | the bench. This is hinged with 14-in. | bolts about 8 in. above the bench top. | Canvas is tacked to the lower side of the When lowered, this convenient hardware holder allows the contents to be sorted. frame so that it sags sufficiently to make a good pocket. One end of the canvas Is left long enough to reach the wall at a point halfway between the pivot bolts and the hook which holds up the container. When this holder is open, all the parts | are spread out. As soon as you have picked up what you need, the frame can be raised and hooked, with all the parts entirely out of sight and off the bench top.—K. RENNER. M.

Page 113

run- | Wire | ma ire | ~~ @m ? . — me wm © ~ we OO Ww May, 1930 | SLUEPRINTS FOR YOUR HOME WORKSHOP each 15 by 22 in. Airplane Models 50. 36-in. Rise-off- Ground Tractor 69. Lindbergh’s Mono- plane (3-ft. fiy- ing) 82. 30-in. Single Stick 86. 35-in. Twin Pusher 87. 30-in. Seaplane 89-90. Bremen (3-ft. flying), 50c 102. Morris Seaplane (record flight 12% min.) 104. Tractor (record flight 6,024 ft.) Furniture 1. Sewing Table 2. Smoking Cabinet 3. End Table with Book Trough 5. Kitchen Cabinet 13. Tea Wagon 17. Cedar Chest 18. Telephone Table and Stool 19. Grandfather Clock 20. Flat Top Desk 21. Colonial Desk 24. Gateleg Table 31. Two Sewing Cabi- nets 33. Dining Alcove 36. Rush- Bottom Chair 37. Simple Bookcase 38. Sheraton Table 39. Chest of Drawers 49. Broom Cabinet 60. Welsh Dresser 68. Magazine- Rack Table and Table 70-71. Console Radio Cabinet, 50c 77. Simple Pier Cabi- net and Wall Shelves 78. Treasure Chests 88. Modernistic Stand; Modernistic Bookcase 91. Modern Fold- ing Screens 93. Three Modern Lamps 100. Modernistic Book Ends, Book Shelf, Low Stand 105. Tavern Table and Colonial Mirror Radio Sets 103. One-Tube (battery operated ) 42. Three-Stage Am- plifier 43. Four-Tube (battery operated) 54. Five-Tube (battery Popular Science Monthly, 381 Fourth Avenue, New York Send me the blueprint, or blueprints, I have underlined below, for which I inclose.......... RO Sa oer ee aed cents. Book- Trough, ( ASSIST you in your home workshop, PoPULAR SCIENCE MONTHLY offers large blueprints containing working drawings of a number of well-tested projects. Each subject can be obtained for 25 cents with the exception of certain designs that require two or three sheets of blueprints and are accordingly 50 or 75 cents as noted below. The blueprints are 55. Five-Tube Details 79. Electric 80. Electric High Pow- er Unit 81. Electric Low Pow- er Unit 97. One-Tube Electric 98. Two-Tube Electric 99. Four-Tube Electric 109. Screen-Grid Set Ship and Coach odels 44-45. Pirate Galley or Felucca, 50c 46-47. Spanish Treasure Galleon, 50c 48. 20-in. Racing Yacht $1-52-53. Clipper— Sovereign of the Seas, 75c 57-58-59. Constitution (‘Old Iron- sides’’), 75c 61-62. Viking, 50c 63-64. 29-in. Toy Motor Boat, 50c 74-75-76. Santa Maria (18-in. hull), 75c 83-84-85. Mayflower (17%-in. hull), 75c 92. Baltimore Clipper (8 in. long) 94-95-96. Mississippi Steamboat, 75c 106-107. 42-in. Racing Yacht, Sea Scout, 50c 66.Ship Model eather Vane 108. Scenic Half-Model of Barque 110-111-112. Schooner Bluenose, 75c 115-116-117. Concord Stagecoach, 75c Toys 28. Pullman Play Table 56. Birds and Animals 67. Lindbergh’s Plane 72. Colonial Doll’s House 73. Doll’s House Furniture 101. Fire Engine, Sprinkler, Truck, Tractor 113. Lathe, Drill Press, Saw, and Jointer 114. Airplane kpit with Controls Miscellaneous 15. Workbench 26. Baby’s Crib and Play Pen 30. Tool Cabinet, Bor- ing a and operated) Price 25 cents each except where otherwise noted City and State. ............ h 65. Six Simple Block Puzzles J POPULAR SCIENCE MONTHLY Hj, ..-.oOne big reason for Silent Automatic heating efficiency Radiation Conduction Convection It is not by accident that Silent Auto- matic owners become so genuinely enthusiastic over the efficiency and economy of this world-leading oil burner. Qf the three methods for conveying heat (illustrated above) convection, which is the direct application of heat to the surface to be warmed, is by far the most rapid and effective. The famous Silent Automatic wiping Wall- Flame is thrown against the furnace or boiler wall with a wiping action which enables this clear, clean flame to deliver a maximum amount of useful heat. When you see a Silent Automatic in actual operation, you will under- stand even more clearly why “Silent” heating is so satisfactory in homes of all kinds and sizes, and why it costs no more (and often less) than coal, © PSS Mibgyg cn 111 y) yyy : Thousands of Silent Automatic own- ers will tell you that no other home improvement has ever meant so much in all around satisfaction, relief from dirt and drudgery and better family health. A Silent Auto- matic can be installed in any type of heating plant—steam, hot water or warm air—in a few hours. Mail the coupon for the complete facts about the low cost, economy and wonderful dependability of Silent Automatic oil heat. oe Cc Oo U t P Oo N SILENT AUTOMATIC CORPORATION, 12001 East Jefferson Avenue, Detroit, Michigan Gentlemen: Please mail me, without cost or obligation, your latest booklet, “The Intelligent Selection of Oil Heat for the Home”. Name City State Street Address. (259) © This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. ISP STS

Page 114

POPULAR SCIENCE MONTHLY MR. PUNCH -- THE HOLE MAKER and his PARTNER the AUTOMATIC SPIRAL RATCHET SCREW DRIVER Mr. Punch is an automatic drill, carrying in the handle eight sizes of drill points 4%" to %%". Around the top are sample holes showing the exact size made by each drill point. Pick out the size you want, insert it in Mr. Punch’s steel jaws, place point where you want the hole. You push. He twists. In goes the point, and presto, you have a smooth clean hole in any wood. It can also be used for making holes in plaster. The handiest tool ever invented for house- hold use. *811A Automatic Screw Driver has three distinct advantages. It auto- matically drives or draws screws. The auto- matic action can be locked and the tool-used as a right or left hand rigid screw driver, or all actions can be locked giving a plain rigid screw driver. Supplied with three quickly inter- changeable blades. are either highly polished or nickel plated. Examine These Two Fine Tools At Your Dealers a —— ——s Send $1.00 For Handy Pocket Screw Driver Set To introduce a sample of Goodell-Pratt quality to every tool lover in America, we are offering this handy tool at the special low price of $1.00. Ideal for repair work on radios, firearms, fishing reels, clocks, household appliances, etc. Contains three screw driver blades and reamer. When not in use the chuck and blades are inside as shown. Nickel plated handle. Pin Dollar bill to this coupon and send in to- day. GOODELL PRATT 1500 GOOD TOOLS GOODELL-PRATT CO. Greenfield, Mass. Attached is one dollar for one of your pocket screw driver sets. Name. Street My dealer is RRR SERENE AF LEE Se City State May, 1930 \ smooth easy operating screw driver that | appeals instantly to the toolwise user. It | The exposed metal parts | ee HOME WORKSHOP| CHEMISTRY THE varnishing of small metal articles | such as toys is best accomplished by the dip process, especially if many pieces are to be handled. Shellac varnish is ex- cellent, and so is the pyroxylin or cellu- | loid lacquer. Both of these finishes may | be colored with dyes, if desired. They give a hard, shiny, durable coating, and the lacquer in particular is not affected to any great extent by moisture. A dressing for leather belting which prevents slipping is always useful in the modern motorized home shop. Melt to- gether 5 oz. of spruce gum with 1 oz. of ozocerite or what is sold also under the name of cerasine (this is a harder paraffin resembling beeswax) and 3 oz. of rosin.. When melted, remove from the fire and add 2 oz. of turpentine. Allow the mixture to become cold and add 10 oz. of alcohol. Brushing a homemade dressing on a leather belt to prevent it from slipping on the pulley. Shake the dressing before applying it with a brush on the inner side of the belt. In order to increase the hardness and strength of paper ornaments, boxes, and novelties, they may be painted with boiled linseed oil. This treatment should be repeated until the oil will no longer penetrate. The drying may be hastened by placing the paper articles in a moder- ately warm oven, but care should be taken / not to heat them to too high a tempera- ture. Similar results are obtained if the paper or cardboard is painted with specially prepared carpenter’s glue. The glue is made ready by dissolving it in water, draining off the excess water, and dissolv- ing the swollen mass with heat. Then acetic acid is added in such a quantity that the glue will remain fluid. Repeated applications of this glue will harden thin cardboard, especially if it is porous, to the solidity of wood. Treated in ‘this manner, the cardboard may be made waterproof by painting or varnishing it with a good grade of spar varnish. Models of boats, stagecoaches, build- ings, and the like may be easily made from this cardboard. Parts that require to be bent can be softened by brushing them again with the glue. The various pieces may be held in place by rubber bands while the glue is drying. When the model is finished, it should be brushed repeatedly with the glue.—H. Bape. 9 This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8.

Page 115

cles | by | Ces ex- | Hu- | nay | hey and ted ‘ich the _ of the fin sin. . ind ure ol.

| “Ss =O Me OD Se

May, 1930

Easy Way to Make Wheels for Model Stagecoach | fen may be those who, like myself, have had trouble in sawing the felloes of the Diamond Tally-Ho stagecoach model. I eliminated the sawing entirely by turning them on the lathe. A backing of pine 34 in. thick and 8'% ijn. square was screwed to the faceplate. The corners were then cut off and the piece was rounded. To this piece was screwed an 8-in. square of plywood } in. thick, the screws being kept near the center. Both the rear and front felloes were then turned from this plywood. Either a parting tool or a skew chisel may be used, but the latter is the quicker. Felloes are made quickly and simply by this method, and the flat turned edges allow the assembling and finishing opera- tions to be performed without difficulty. Another suggestion for stagecoach model makers has to do with drilling holes in lead or soft solder with a twist drill. It is a good idea to put a soft piece of candle wax in the hole just as soon as the drill has been centered. This insures a smooth hole of the exact size of the drill. Whenever the drill is removed to clean out the cuttings, a small piece of wax should be inserted. Woodworkers may find their drills too soft for the harder metal parts of stage- coach models. One way to harden the drills sufficiently is to hold them with pliers, heat them until red (not white) hot, and then shove them into a box filled with tallow. If larger than 1% in., the drills should be kept in the unmelted tallow until cold. The point will be hard and the shank tough, and no tempering is re- quired.—H. CALDWELL. Where to Look for Other Mechanical Articles M ANY short articles of interest to me- chanically minded mer are scat- tered through the magazine in the sec- tions preceding the Home Workshop Department. If you happen to have missed any of the following, it will pay you to turn back to the pages noted and read them. Oil Makes the World Go Round.... 27 Superchargers for Diesel Engines.... 29 Depth Gage Used on a Square..... 34 A Nonskidding Screw Driver....... 36 Auto Trailer Has One Wheel....... 38 New Bricks Are Twenty Feet Long.. 50 Diesel Auto Runs 26 Miles on Gallon 52 A 9-Cylinder Engine Size of Hand... 66 Welded Truss Holds Million Pounds 66 Home Conveniences That Save Time 68 Circuits That Improve Tuning..... 71 In Radio—Look Before You Buy... 73

To TURN a tight fruit jar cap, run a wide rubber band around it and another around the base of the jar, at the points where you grip each. The bands hold these sur- faces like a pipe wrench and, at the same time, form a soft, nonslipping contact with your hands. In the absence of wide rubber bands, small ones or any other scrap rubber such as part of an old rubber

| apron will help.—WorTH STEWART.

POPULAR SCIENCE MONTHLY 113 The board of 1OO uses for use in LOOO places OTHING is handier about the house than a few panels of Upson Board. | You will find dozens of uses for it. can be sawed or cut with a sharp kni racks, countless other articles which wi

| Nothing b better than Upson cracked ceilings. Characterful—crackproof—SAF —Upson Board does not add dangerous weight. ife, like soft pine—and finished as desired. It is used for screens, table tops, tool hampers, sewing boxes and

Board rm geen suggest themselves to the handy man. Manufacturers use Upson Board in place of thin lumber in the manufac- It ture of their products. It cuts costs and speeds up production. It can be cut to any size or shape. Our Industrial Ex- perts will gladly work with manufac- turers in helping solve their particular ll problems. Phrase Copyrighted 1911

Upson Board i in Relief Treatment like this will give m all the aristocratic beauty of plaster—at a fraction the cost. we <a

Your home is you. It gives every one a good or bad impression rontian, crawling, plaster crack are so unnecessary amywhere! Upsonize—today! onnee

Your dining room can be made as bright and attract- s ive as this—with Upson Board laid rightover the old plaster—or in a new home, direct to studs and joists.

able—easily

Transform thatoft-neglected bath or Sed Upson Fibre-Tile ae andeasy to instal —smart—wash- in any color scheme youchoose. The aver: kitchen.

woman spends a third of her time in the ransform and modernize it with U, Fibre-Tile—at about 1-10th the costof ceramic tili

UPSON BOARD and TILE

The Upson Company, 533 Upson Prt., Lockport, N.Y. Beary find 10 cents for samples of Upson Board and Fibre-Tile, literature describing the new Upson Roel Ceiling and folders showing how Upson Fibre- Tile builds colorful kitchens and baths. I am interested in C Walls and Ceilings (2 Industrial Uses + ) . * upson Street eRGOUCTS ©1929 The Upson Company, Lockport, N.Y

Page 116

114 When a Defective Screw Might J Mean Disaster... # You are playing ps safe if you use — American Screws. - Small things, a screws, but very oo important ones In Garg modern construc- 1 tion. American Screws may be depended upon to drive straight and rapidly; once in place to hold fast. For almost a century American Screws have set the standard of quality and efficiency. Insist on American Screws gt he ‘- eS Hench STOVE wood MACTANE Tet SCREWS SCREWS BOLTS BOLTS AMERICAN SCREW CO PROVIDENCE,R.1.,U.S.A. WESTERN DEPOT, 225 WEST RANDOLPH SLCHICAGO.ML, Put lt Together With Screws POPULAR SCIENCE MONTHLY Tooled Leather Book C May, 1930 ver By F. CLARKE HUGHES and beauty, is an ideal material for making a removable book cover. A 9 by 13% in. piece of calfskin (tooling calf preferred) is used for the outside covering, marked No. 1. This makes a cover large enough for the average novel | EATHER, because of its durability . SIMPLE LINE TOOLED AS or textbook. Two pieces of the same stock 2'% by 9 in. will be needed for the inside end pieces. The lining leather, marked No. 2, should be the same size and shape as No. 1, and may be either thin lining kid, calf, or ordinary silk. The marker, No. 4, is cut to shape from a 3 by 12 in. piece of thin leather. eee UGS noes FC NO. The decoration on the DECORATION NEEDED 5 P0032 cover may be anything in NO.1 NO.3 : — rae Hy . = the way of a simple design; = however, it is suggested that NO.2: ‘' GLUE EDGES j ; Tenty serone a simple border line such as , PUNCHING AND shown in the illustration be NO3> ; OU i. | NUMBERS 1 AND 2 | ARE THE SAME SIZE | NUMBER 2 MAY BE ‘ie EITHER THIN LINING | LEATHER OR SILK —; +4 y= TWO NEEDED CALFSKIN = = Sate ™ LEE A NO4 THIN LEATHER MARKER pate cat: The cover is made up of five pieces. Note how the edges are laced and method of cutting the laces from scrap leather. LACING LACES MAY BE CUT SPIRALLY = # FROM A SMALL SCRAP OF used. This may be tooled or pressed into the damp leather with a very blunt- pointed tool or awl used against the edge of a ruler. and polished on the work- ing end. A soft, blunt- pointed lead pencil may be used if a dark colored line is not objectionable. Assemble the various parts and punch the holes as indicated with either a regular leather punch or a nail filed flat on the end and used on the end grain of a block of wood. The lacing can be cut 1% in. wide from scraps of leather—prefer- ably kangaroo or wallaby skin. Lace the edges witha simple spiral stitch. When entirely assembled, the cover should be polished with floor wax. Automatic Holder Grips Broom Handles yy mat my wife wanted was a place to hang brooms and mops, so I made the automatic holder illustrated, tested it, and triumphantly called her to behold a gadget that really works. The main piece of the holder is a strip of wood 34 by 234 by 17% in. with four notches, each 1% in. deep. The notches are cut in straight at the right-hand side but at a slight angle at the left-hand side, as shown, so that while each notch is 254 in. long at the top, it is 234 in. long at the bottom. The notches are 11% in. apart. The locking cams are 1% in. long, 134 in. wide, and 34 in. thick where they are LOCKING CAMS The movable cams and the stationary pieces are covered with a 34-in. strip of inner tubing. The holder automatically grips the handles of the brooms and mops at any point desired. hinged. They taper to a rounded edge as indicated. . When the cams are hinged, the ends of a 1% in. wide strip cut from an old inner tube are fastened beneath the flaps of the hinges and are held in place by the screws. This free loop of rubber is then stretched around to cover the locking cams and the projections as illustrated. The holder is screwed to the wall and reénforced with two 34 by 234 by 234 in. wooden brackets placed under the second and fourth sta- tionary projections.—R. P. GRANT. The tool should be smooth | M.

Page 117

1930 me he er ize er he 34 ‘in a May, 1930 Colonial Doll Cradle and Four-Poster eS. who delight in copying old furniture will find that the doll’s cradle and bed illustrated are construction and design. Both drawings were taken from pieces made in the early part of the nineteenth century as min- iature copies of the full size furniture of that period. Soft white pine is used in the con- struction of both toys, and a dark brown Perspective of the bed and details of the turned parts. stain and two coats of varnish are all that are required for the finishing. With the exception of the bottom board and the rockers, %-in. stock is used throughout for making the cradle. The front and backboard are first nailed and glued between the sides, and then the bottom is fastened in place. Next, cut the hood pieces to shape and nail them on top of the sides, and then fit the curved apron. Rockers made from %-in. stock are nailed and screwed in place from the inside of the cradle. Sandpaper the entire piece, carefully rounding all the edges. The bedposts and upper crosspieces for the doll’s bed can be turned in the lathe from 1% in. square stock. It is also possible to make them by gluing small wooden spools on %- or 14-in. dowels. The lower cross rails are fitted to the corner posts with short 4-in. mortise and tenon joints. Drill a series of 3%-in. holes in the lower rails and through these lace the cord as shown in the drawing. This method of supporting the mattress was used in many old bedsteads.—F. J. B. Assembly view of the cradle and dimensioned views of back, sides, rockers, and foot piece. a interesting projects. in early American | POPULAR SCIENCE MONTHLY . FREE!? A whole week’s better shaves. Just mail the coupon below This kind of shave lasts longer by softening the beard at the base, right where the razor works ...... Lesa you shave with Colgate’s small-bubble lather, you can feel satisfied that your shave is bound to last longer... because you’ve shaved closer. Those small bubbles make a lather which moistens the beard down at the base .. . as big- bubble lather can’t. Small bubbles bring more moisture to the base of each hair, softening it more thoroughly, making it easier to cut. The minute you lather up with Colgate’s, two things happen: 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, aftervarious trials with ordi- nary lathers, have adopted Colgate’s as supreme.To prove its superiority, mail the coupon below. We will send also asample of After-Shave, a new lotion —refreshing, delightful...the perfect shave finale. Small-bubble lather permits closer shaving... Ordinary, big -bub- ble lather (greatly magnified). Note air- filled bubbles which can’t soften the beard efficiently. Only water can do the job. Only small bubbles permit suf- ficient water. Colgate’s lather (greatly magnified) showing moisture contact with beard and minimum air. A common-sense principle scientifi- and proved out practically by mib lions of men. Post Office, New York City. have.” COLGATE, Dept. M-722 P. O. Box 375, Grand Central Please send me, FREE, the seven-day trial tube of Col- ~- Rapid Shave Cream; aleo a sample bottle of “After-

Page 118

116 ee TE EEE ee — For subjects that are hard to get—always take along a Graflex Camera! Graflex pictures live! And the unique construction of the camera itself makes the most difficult subjects surer...simpler...for ama- teur and professional alike. RICHARD K. WOoD ILD-LIFE photographer, writer and sportsman, Mr. Richard K. Wood, who took this thrilling wild-life pic- ture, has roamed the length and breadth of the continent armed with 4 Graflex, his fa- vorite camera. He has braved the elements in the Northland when the thermometer hov- ered around 40° below zero, sweltered in Florida palmetto jungles while waiting for rare bine herons. In Physical Culture i Mr. Wood tells how his Graf- lex ‘‘made a new man of him,”’ kept him out of doors and transformed him from an ail- ing, weak youth into a hardy and healthy man of the open. He 3 eo ag m4 serv- ices of a ician for the ten years. Graflex has sa be him a remunerative hobby— and it has brought him health. The CAMERA For More Interesting Pictures FOLMER GRAFLEX CORPORATION, Dept. 15, ROCHESTER, N. Y. I want to see the booklet that "Heme ned edd en ee mae, Please send ‘“‘Why a Graflex?” to name and address written on’ margin of POPULAR SCIENCE MONTHLY ° May, 1930 How to Make Cork Bodied Lures for Bass and Trout By ROBERT PAGE LINCOLN Bye bodied lures for use in fishing for trout and for small-mouthed bass and its more common cousin—the large- mouthed variety—can be easily made by the sportsminded home workshop en- thusiast. Ordinary bottle corks will not answer | the purpose, but high-grade cork can be purchased from any large sporting goods establishment or tackle maker. Fine OY ARCKLE - FEATHER \ Fig. 1. How the hook is attached to the cork body and a 1%- in. bass lure. Fig. 2. A %-in. bug. Fig. 3. A variation of Fig. 2. quality cork is not only very tough but its buoyancy is far greater than that of cheap cork. Bass bugs can be made any size de- sired, ranging from a No. 6 to a No. 1-0 hook. The so-called O’Shaughnessy hook, hand forged and filed, is probably the best suited for the work. Most fly makers in preparing the cork body of the bass bug simply cut a slit lengthwise on the underside of it, press the shaft of the hook into it, and then wrap the entire body with silk thread. This does not, how- ever, prevent the cork body from turning on the stem of the hook. My own method, as shown in Fig. 1, suggests soldering two pieces of wire at right angles to the stem of the hook. ‘The size of these pieces is governed by the size of the body of the fly; on a No. 1-0 hook they are 4 in. long. In attaching the cork body to the hook stem, cut a slit along the underside of the body and press the hook stem up into it. The points will drive into the cork and hold the body in place. The lure shown in Fig. 1 is 114 in. in length and 76 in. thick at the head. This fly is painted over with regular artist’s —— MA _ wana He

Page 119

rk —NN ORDA SW wor wee May, 1930 EI POPULAR SCIENCE MONTHLY 117 There is a job for you in Aviation = Practical shop work in a Universal School. Many graduates of the Universal welding course are employed at good pay in airplane factories. & ae _ all ill ull i oe ett HLL A typical class room in one of the schools of this national system. INFORMATION BLANK Fill in and mail UNIVERSAL AVIATION SCHOOLS, 1046-55 Boatmen’s Bank Bldg., St. Louis, Mo. Please advise me what training | should take. I prefer position as Pilot___.-...---------- ’ Mechanic___., Welder__._, Office Work----. ee Lee Age-__- ee: ne ae i oo, ee Telephone Number _-_____----------------- My past experience is_____...------------- Do you want to become a pilot? A mechanic? Awelder? Do you want to enter the business end of avia- tion? Then send in the coupon with the information which we ask and let us advise you how to realize your ambitions. How We Assist Ambitious Men When you return the coupon, we study your qualifications. If you need special training to reach your goal, we tell you just what kind you should have. We send you, with our advice, an attractive book telling all about aviation and describing the kinds of training offered in this national system of government approved aviation schools. A National Employment Service Universal Aviation Schools are a division of the American Airways, Inc., the world’s largest air trans- portation system. This system is constantly opening new routes and employing additional men. Univer- sal graduates are given first consid- eration whenever new men are employed. And other large air transportation systems, airplane manufacturers and aviation supply houses, knowing the UNIVERSAL AAS high type of training offered . SS in Universal Aviation Schools, Universal At least 10 hours training in tri-motor planes is @ part of the regular transport pilot’s course. Let us help you find it turn to our employment department for men with aviation training. Why Universal Students Rank High Universal Aviation Schools are among the few that are government rated and approved. This means that all equipment, instructors and meth- ods of instruction in Universal Schools meet the Department of Commerce requirements. In addi- tion, to retain government approval, these schools must turn out gradu- ates who meet the department's high standards. For this reason only men with satisfactory qualifications are accepted in Universal Aviation Schools. Among the courses offered are: Flying, Mechanics, Welding and General Aviation Business Admin- istration. Also an excellent home study course in Aviation. How to Start in Aviation Mail the coupon giving full details on all questions asked. We will tell in reply wha, training you need and send you the book, “Aviation—What It Means to You.” This book gives qualifications required of students, cost of training and all infor- mation you should have. If you want a place in aviation, fill in the coupon and mail. Aviation Schools A DIVISION OF AMERICAN AIRWAYS, INC. Operating Company of The Aviation Corporation A National System of U. S. Government Approved Schoois

Page 120

118 POPULAR SCIENCE MONTHLY

Thats the Rule 1 want The, FARRAND RAPID RULE The Original Rigid-Flexible-Concave Rule There is something new in craftsmen’s fine tools. It is the FARRAND rule. More rigid than the wooden rule yet as flexible as a steel tape, this remarkable invention will measure all surfaces, whether straight or curved. The FARRAND rule, made of the finest steel in the world, is coiled in a small holder that It is lighter than any other rule of fits the vest -pocket. its length now on the market. Model C, complete with six- foot rule, weighs 214 ounces. By slight pressure on brakes, the rule strip shoots out to any desired length. Your Dealer Will Demonstrate or write tofactory for6-inch sample of rule strip Manufactured by HIRAM A. FARRAND, Inc. Berlin, N. H.

r ! paint; and two hackle feathers 3 in. long are tied on so that they lie over the back of the fly. A wisp of white bucktail is placed on each side of the feathers. Waxed thread should be used for all | tyinz operations.

If desired, the fly body can be coated with a high-grade waterproof varnish such as fly makers use, and the body dusted with gold or silver crystals obtain- able at any large art store. The varnish dries and holds the crystals, which pro- duce an attractive sheen. The bass bug shown in Fig. 2 has a body 34 in. long and 34 in. in diameter. This lure, being small, can be used for trout. The top of the body is rounded,

TUFT OF BUCK HAIR

—$‘~ = A 1 : : C B WRAP HERE r AND TIE Z yy - o~| C>a POINTS SOLDERED »~<2— ON HOOK STEM

CUT HERE FIG6 Fig. 4. A wet type bass fly. Fig. 5. A squirrel- hair lure. Fig. 6. An imitation moth trout fly. but the underside is made flat. The body is attached to the hook in the manner de- scribed above and is placed so that there is at least 44 in. between the end of the body and the beginning of the bend of the hook. A tuft of squirrel hair is tied in as a “tail,” the forward half of it being thrust down under the body of the bug. A hackle feather with filaments 1 in. long is caught in and wrapped around the tail just back of the body. This fly, when dropped on the water and moved the very slightest bit, throws every filament of the hackle feather into action, giving it life that causes even the wisest bass to strike. Only the fact that the body of the bug is 1 in. long and % in. wide and that it has a tail hair tied in such a manner that it stands up at an angle makes the lure shown in Fig. 3 different from that shown in Fig. 2. The writer has landed ten bass in one afternoon with this type of lure. Figure 4 is a bass fly of the “wet” type; that is, it is operated under the sur- face of the water. A tuft of squirrel hair is tied in as shown to represent the wings of the bug. The thicker portion (or butt)

“,.- the end of that ugly hole.” You can easily make cracked walls and ceilings good as new with Rutland Patching Plaster—the quick, money- saving mender. Just mix with a little water, then fill crack or hole. If you want a perfect, lasting job, be sure to ask for Rutland Patching Plaster— made by the secret Rutland formula that insures absolute whiteness and permanence. At paint, wail-paper and hard- ware stores. Rutland Fire Clay Co., Rutland, Vermont. RUTLAND PATCHING PLASTER nx I Ie Lubricates " Polishes Prevents rust finest oil for protection of tools and all small m&- chinery. Never gums or hardens. Colorless, odor- less, stainless. Send direct if 35¢ your dealer cannot supply.

Wm. F. Nye, Inc., Dept. R. New Bedford, Mass. Oil refiners for nearly a century

FLYTHISCOMBATMONOPLANE! This realistic copy of a mil- itary monoplane is an_unu- cuslly steady fi er. Wi iat Wrieht ont own wer and Sy oe t. a blue. Can built in 2 hrs. without tools. Con- struction set includes 6-in. aluminum propeller with shaft, 114 in. diso wheels, wood struts, rubber band motor and all other = with clear directions. Com- plete set, packed in unbreakable container, 7 $1.00, Baws in U. 8. and Canada. Order today. giving full address. Satis- ‘action or money refunded. The Midiand Model Works, Chillicothe, Ohie ( We cannot make C.O.D. shipments. No retail catalogue issueds)

yy -_« 4 TH oe hel hUe* TlU AUC a-_— a OF lee, a

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

BRS Sagres

Page 121

1 FF j+-Prrme rrr eeOses rts COPS }| es oc

May, 1930

of the nip of hair is allowed to stand down below the head. Then, by wrapping the thread backward and up, the tuft is turned back. The value of this tuft of hair underneath is that it acts as a weed guard. A SIMPLE but effective hair fly is shown in Fig. 5. It is made by tying in a tuft of squirrel hair (cut full length from the tail of the animal) at the head or eye of the hook. Wrap a small amount of waxed thread around the hook before you tie the hair in place, so that the tuft will not turn; fasten the hair in place and then gather the hair in and tie it near the bend of the hook as shown. Instead of out- standing wing feathers, use a nip or two of buck hair, turning the ends out on either side, butt ends of the hair i in. Now tie these two tufts in place by crisscross- ing the thread back and forth. Finally, touch the head with fly-maker’s waterproof varnish. This fly is cast like a dry fly and, if possible, to the exact spot where a fish has made a swirl in the water. It settles on the water and will float for a few mo- ments. Then it is picked up and dried by false casts in the air before being returned to the water elsewhere. Figure 6 shows what can be done with a small cork body and a No. 8 hook in making a floating trout fly. Varnish the body of the fly with two or three coats of fly-maker’s varnish. While the last coat is still tacky, the body is dusted over with silver or gold powder. To give the fly the semblance of a moth (which this aims to imitate), cut rabbit fur almost dust fine and sprinkle this on the varnished body. When the varnish dries it will hold the fuzz and colored crystals in place. The body top should be sloped to hold the wing feather at the proper angle. The wing is simply the butt of a feather tied in securely at the head. This fly will account for big rainbows, also brook trout. It is a big killer on sunfish, and is unequaled when fished where “croppies” are known to hide. AM of the various types of bass bugs are manipulated in the same man- ner. They are cast out on the water and allowed to remain motionless for a few seconds; then they are moved forward a few inches and again allowed to remain motionless. This is repeated three times. If no strike is felt, the rod is given a few twitches in order to set the hackle fila- ments in motion; and if still there is no strike, the lure is picked up and cast else- where. With a little practice it is possible to impart lifelike movements to this type of lure. To aid you in your fly tying, you will find a watchmaker’s vise very handy; in fact, almost indispensable. You can obtain a simple little vise in a five and ten cent store that will likewise serve the pur- pose. Ordinary high-grade silk thread coated — shoemaker’s wax will do for tying ies In preparing the hair, feathers, and hackles, it is well to do all of the dyeing at one time and to have a sufficient supply of everything on hand before the work is begun.

POPULAR SCIENCE MONTHLY 119 WittiaMs ICE-O-MATI brings you all all these 15 modern advanta ges NEW CAPITOL ; MODEL jig! ped you can enjoy a// the 15 modern advantages of electrical refrigeration at low cost. These most important features have all been combined, for the first time, in this new low-priced Capitol model of Williams Ice-O-Matic. Williams—whose Oil-O-Matic burners are in far more homes than any other make—invested 12 years and a good sized fortune developing this advanced new Ice-O-Matic. Ice-O-Matic’s greater cooling capacity permits shorter operating periods and reduces current cost. Thousands of owners say Williams Ice-O-Matic literally pays for itself by preventing food spoilage. Mail the coupon now for further interesting facts that will safeguard your family’s health and lighten housekeeping, especially during this summer. ICE-O-MATIC CAPITOL FEATURES

NEW CAPITOL MODEL $17 5 yt ha ICEeMATIC

1 Unit on top or inside cab- 6 Tem Ph any ne M.. control for ]] Constant, healthful low inet, or in ement temperature 2 Hermetically 's sealed; access 7 Aaisto' ice cube capacity 12 Plugs into light socket— sible mechanis simply as a lamp 5 ieee § Feet End chiee— 13 Chromium plated hard- 4 Forced circulation of cool- 9 Three-inch insulation— 14 Quiet operation—no radio ing air moisture proof Mechanismoperates shorter 10 Roomy, convenient food 15 Built Williams way for life-

time, uses less current compartment time service ICE-O-MATIC DIVISION WILLIAMS OIL-O-MATIC HEATING CORPORATION Factory, Bloomington, Illinois Dealers Everywhere => R A D I oO 2 ; SSS Williams Oil-O-Matics Send for Ice-O-Matic Recipe Book— It’s Free SUNDAY EVENING, 7:30 to 8:00 |! Williams Oil-O-Matic Heating Corporation (Eastern Time) NBC Chain, WJZ, |! — Bloomington, Illinois P.S.5-30 | WBZA, WLW, WHAM. [: —— fee L/ R, WGN, KWK, WREN. : Please send me — without cost—your Williams Ice- ; WEDNESDAY EVENING, 7 30 0 | CSRs socipe Sookie. : to 7:30 acific Coast R, : Name <EX and KGA. Time) KR, | THURSDAY EVENING, 7:30 to | Soveet to : 8:00 (Conceal Time) WEN. SATURDAY EVENING, 8:00 s : Gi 8: 30 A ed :Time) RRO RM i Caty.

State

Page 122

, eo — " Send for ‘eicimy Sample of WATERPROOF The

ties Strongest ue ~| Adhesive a as oc oe Sa 3=<==—)| Known

In addition to unfailing and lasting adhesive qualities CASCO has many advantages over ready mixed liquid glue or bulk glue. It glues prac- tically everything, wood to wood, metal, glass, cardboard, leather or paper—and glues it permanently. No waste. One pound of the dry powder makes 114 quarts of liquid glue. And it’s all glue—high powered —wide-spreading. No heating. Mix it in cold water and use it cold. No odor. The unpleasant reek of “cooking glue” is gone when you use Casco. It’s clean and convenient to use. Strength. A Casco-glued joint is stronger than the wood itself. Waterproof. Casco Glued means glued permanently to withstand moisture or atmospheric changes. Endorsed. Leading aeroplane and woodworking industries have for years put the seal of their approval on Casco. Convenience. Now Casco is avail- able to you in 4 or 1 lb. packages. Try the 10c sample on your next gluing job. You can glue it better with Casco. Fill out completely the coupon below— one test will convince you that Casco is the most practical, durable, con- venient and inexpensive glue you have ever used. THE CASEIN MANUFACTURING COMPANY of 205 EAST 42nd STREET NEW YORK

The Casein Manufactering Company of America, Inc. 205 East 42nd Street, New York Enclosed find 10c (stamps only) to cover postage and handling cost for which send me your trial package of Casco Waterproof Glue. DE Wdn teeth deeb RO 6b NA ONE 006666005 00-0:00006.00'0 CH Si cenersnvccccssccsecseecn errr re bm ~ Patnt, or Lumber Dealer's Name (Please In- ude) (DECIALINTRODUCTORY TRIAL OFFER

POPULAR SCIENCE MONTHLY

Three-Sided Bird House Has Many New Features By GEORGE SHARP EACTING to the breeze like a small weather vane, the bird house il- lustrated turns with the wind and keeps its entrance always on the lee side. Though primarily intended as a wren house, a few alterations in the dimensions will make it adequate for birds of any size. Unlike many wren houses, it has an opening that is fully large enough for the enter and bring with them the material that they use to build their nest, but too small for any other bird. Just out- side the door is a porch or platform. Since it is shielded with the tin sides G, it is well protected from the wind. The tin also serves as a vane to cause the house to turn in the wind. The sides of the triangular house are made from 1%-in. stock; they are 8 in. high and 6% in. wide. The three pieces that form the roof can be cut from the same stock to the shape of isosceles triangles having bases of 11 in. and heights of 5% in. The sides are mitered so that they fit together snugly, and reénforcing blocks B are placed in the corners. Roof supports A are placed in the middle of each side. ~ The house is hung on a brass chain. | The roof pieces are held together with | corner pieces C.

A Y@-in. space around the top and bottom pieces form a drain for any rain TIN WOODEN APEX

FRONT SIDE X6 Front and sectional side views of the house. Note the construction of the entrance grille. wrens themselves to |

If you’re one of those fellows who think that work- stained hands can’t be cleaned, I’ll bet you’ve never tried Lava Soap. For more than 30 years men with jobs like yours have been using Lava p... because it gets the grimiest, greasiest hands clean in 58 seconds, without hurting the skin... because it makes a lather rich as cream in the hardest water. Here’s the secret of Lava’s speed, thoroughness and gentleness. In addition to pure vegetable oils, Lava contains pulverized Italian pumice. That’s what makes dirt and grease disappear so quickly, without harm to the skin. Get a cake or two tonight and see if I’m not right. Geos Lee fase Soop Man Lava costs adime (or 6c for the medium size cake) at any drug or grocery store. But if you want to try it at our expense, mail this cou- pon. Procter & Gamble, Dept. X-530 Cincinnati, Ohio George: I want a free sample cake of your Lava Soap.

seed He. 3 OTHERS! Dual Control Rudder In 193 recent test flights out of 200 the Kingsbury Silver Arrow Flying Plane outflew all others, regardless of price. Most sensational plane ia years. Not a construction toy but fully built. A moment to assemble and it’s ready to fly. Made of wood and aluminum; aluminum pro; A adjustable wi and dual control rudder; strong elastic motor. odel No. 3, Racing Type, wing spread, 33 in, $3. (West of Miss. $3.30), Other models. Racing and Cabin Types, at $1 to $3.50. If your dealer cannot supply you, send your order to us. Kingsbury Mfg. Co., 107 E. Myrtle St.. Reene N. Join the Silver Arrow Flying Club and become a Master Pilot. KINGSBURY ¥9T22 TOYS

FREE: Novelty Send 10c for Moviescope; shows Xs Wheel,” Balloo Also complete toy Tire Eraser, Sa catalog. of 4 35c Large 6-foot air with inflators, pa chute and com a. 41 — for flying. Send name and we'll send 6 of our new re- prints of wonderful oil painting pictures to dis of onspecial2Scoffer.Send$1. ect and for thisservice we wi eo wonderful Airship with instructions free. C.M. THOMAS, 337 W. Madison St. 5 K 46

SEMI-BUILT any type or size, assemble yourself, save half. Stamps for catalog. TRUSCOTT BOAT CO. Dept. D St. Joseph, Michigan

— —- Ph ~~ 65S re on

Page 123

1930 May, 1930 POPULAR SCIENCE MONTHLY 121

water that may get into the house. Under the main bottom piece, another triangular piece is placed. This acts as a damper and is not screwed up flush with the bottoms of the sides (see drawing at bottom of page 120). ’ The grille at the 7 in. by 3 in. opening is made of wire and is set in the porch and the rectangular strip over the opening

4 By o& / a TIN N iL : APEX-F oot y bs e e% Seay Ht r / / EE | ees = = — = —| ork. x pT th wer wn’ ( : — Log / Z r— : \ bel ; pes ca . * E ie’ ss 5, : ve —y ——— \e= i. ~~. nes Mi, > ‘ 18 et 38 Af a : S| eee )«6©6READ-RITE — * *kly, q Th — _ o WY 65254 ght. . —¢ TRIANGULAR “OOS XX No. 156 TIN CAP- &. *\\ S | < | ” 7 \\t eee eS | -- a new ofanley kKule ; nye - view showing the paeiiee by 6c the roof and a perspective view of the apex F. | READ RITE” expresses exactly the advan- (see the drawing at bottom of the page). tages of this new Stanley Rule. The figures he 5, Os eee ee read from right to left on the inside of the receive two dry cell nuts and riveted over ” . ‘i at the other, is passed through a hole in tule. When the rule is held in the left the top piece and through a 22-caliber : : V4 shell soldered to the tin apex at the top of hand and opened either partly or to its the ge shown in the lower drawing on full length, the figures and raduations page A . . 4 . If intended for bluebirds, the house lie flat to the work and are rig t side up. should be made 10 in. high and the open- ; : , r ik ing should be 134 in. wide instead of 74 in This new handy marking will be appreci- “and n hanging e house, e bottom . . si should be at least 6 ft. from the ground; ated by ° Arc itects, Contractors and nat and if children are frequent visitors, at Carpenters for checking and measuring ; least 8 ft. should be allowed. .- 9 ea : Plumbers, Steamfitters and Electricians for

measuring in close quarters where the rule cannot be opened to its full length; Masons, Stoneworkers, Steelworkers—every crafts- man connected with the building industry.

cH $s % THIck fT — e cn bh in ty et = — SLOTS i ip = GRILLE ie SIDES

Durable white enamel finish with Red elongated diamonds on first and last stick. Concealed joints. Strike

iy N C Plates. Six inch folds. Joints, Tips : a i I sTBLS and Strike Plates are brass plated. . SIDE iy + ane Made in three sizes—4, 5 and 6 feet. : inca tA S Ask your hardware dealer to . aa & show them to you. OPENING @ Look for the rule with the Red Diamonds THE STANLEY RULE & LEVEL PLANT New Britain, Conn. SOLDERED

= ss Nes STANLEY TOOLS Perspective view of the body of the house and The Choice of the Trades un sketches of the grille, rod, swivel, and hook.

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

Page 124

122 » © Stow to TAKE CARE P cs PIPE i} IR WALTER RALEIGH had a hunch that pipe-lovers would welcome some practical hints on how to take care of a pipe. It was a good hunch. Thousands of pipe smokers have sent for this free booklet. It tells you how to break in a new pipe —how to make a good pipe smoke smooth- er and sweeter—the proper way to clean a pipe—and many worth-while hints on pipe hygiene. If you haven’t sent for this booklet, write for a copy today and find out what pipe makers and pipe-lovers suggestdoing tokeep your pipe sweet and mellow. Just write to the Brown & Williamson Tobacco Corpo- ration, Louisville, Kentucky, Dept. 87 Sir WALTER RALEIGH Smoking Tobacco It’s milder POPULAR SCIENCE MONTHLY ‘THE SHIPSHAPE HOME Electrical Helps for Handy Men Araspy, grating noise is caused by pull- ing the chain to light one of those white kitchen units placed near the ceiling. How can it be avoided? NSTALL a switch of the type shown. The noise is caused by the use of a pull-chain receptacle within the fixture, and its chain comes out of a hole which is not smoothly bushed. To install the new switch, pull the old chain to the “‘on”’ OLD RECEPTACLE Switch E can be used in outlet boxes A, canopies B, ceiling pans C, and office and store units D. Another type F is for use on chain fixtures. position and cut it off close to the fixture. Loosen the fixture from the ceiling, and at a point in the side of the fixture near the top you will find a “knockout,” ‘which may be pushed in with a screw driver. This leaves a hole for the new switch, which is connected in series as shown by cutting the black wire, if the wires have colored coverings. The switch cover is then replaced, the knurled ring un- screwed, the end pushed through the hole, and the ring screwed on, clamping the switch in place. Refasten the fixture to the ceiling. Other uses for the switch are suggested in the drawings above. May, 1930 6 If you want to add from $10 to $35 a week to your present earnings, here is your chance. Hundreds of men are mak- ing good money filing saws on the Foley 6 Automatic Saw Filer. The Foley Model F-5 “3-Way” i: Saw Filer. Files all kinds of hand saws, band saws and Circular Saws on ONE machine Easy and pe to operate. No eye- strain. Adjust the saw in machine and turn on the wer—it runs automatically. -_ Have Your Own Business Many men are making big money with their Foley saw filing businesses. Steady, repeat customers bring them a regular in- come. Become Independent! Have your own cash business, too. Free Plan helps you start. Coupon brings it. Foley Manufacturing Co. ; 1015 Foley Building 1 11 Main St.N. E., ‘ Minneapolis, Minn. \ 1 ! Please send me your Free Plan and tell me how I can make Cash in my Spare Time, FOR THE BOAT, ENTHUSIAST At Last A real appropriate watch charm or coat lapel ensign for ship model makers 01 or boat enthusiasts. This minia- ture steering wheel is made of heavily plated 18-Kt. gold soaks and hub. The rim is made f coco-bola (a Porto Rican heed red wood). Made in two yo For the charm, one spoke h 2 small ring attached. The la style illustrated, has a threa: and nut for fastening. Can mention style when ordering. MODEL SHIP SUPPLY Co. Dept.T MINEOLA,N. Y. Is it possible to obtain - a surface-tyve toggle or tumbler switch? NICKEL OR Yes. When it is neces- sary to use a surface switch in a new installa- tion or when an old surface snap switch has to be replaced, it is well to use one of the new surface-type* toggle switches illustrated. A new type of surface switch. What are the advantages of the new screw-base two-way sockets with a pull chain? It is especially useful where a key socket | is at present used on a fixture and an ZIP-ZIP SHOOTER IHOUSANDS of ‘boys are... made Te with stale wonderful Zi Zip Fig stamps, money order. aere MATIC BBER CO. ‘ee $s. Cc. rene FORMS TO CAST LEAD SOLDIERS, INDIANS, TRAPPERS, Hunters, Wild and Farm Animais. 222 Wonderful ‘“True to Life” models. Easy and inexpensive to make. I furnish all necessary material. Send 5e Stamp for Illustrated Catalogue. Henry C. Schiercke, 1034-72nd St., Brooklyn, N. Y- © This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. we ne an a i.

Page 125

1930 D3 ak. ley J) mr rm rem mee ee SH ow SS S=ee May, 1930 —— iron or other appliance is connected in addition to the light. The pull chain makes the operation of the light much more convenient, since it is independent of the tap on the side for the appliance (see illustration below). The tap is al- ways “on.” A standard shade holder may be screwed on the bottom of the socket, making it possible to use the old shade. NEW PULL-CHAIN TWO-WAY SOCKET CHAIN i —*— FIXTURE OLD KEY SOCKET FOR IRON OR OTHER APPLIANCE ills > CHAIN CONTROLS’ SS BULB ONLY A two-way pull-chain screw socket supplies a socket for a bulb and one for an appliance. SHADE HOLDER SCREWS ON HERE SHADE How can the fraying of a used appliance cord be prevented at the point where it | is grasped just outside the plug cap? By using the newer handle type of at- tachment plug cap shown below. When a wall receptacle is new, it is often hard to remove the cord because of the tight spring contacts. Re- peated pulling on the cord often re- sults in crossed wires in the cap contacts. It is easy, however, to changetothe new handle type plug by loosening the screws in the old cap, untying the knot (if one exists), and removing the cap. Slip the new one over the cord, tie an Underwriter’s knot, and make the bared ends of the wires fast under the screws. HANDLE ON ATTACHMENT ‘\ PLUG CAP Handle plug eliminates traying of the cord. What is the simplest way to make an extension from a base or wall receptacle to another outlet or light in a new location? The usual way is to carry the BX cable from the new outlet to the box housing the old receptacle, and to splice, solder, and tape the joints. By means of the new receptacle shown at the bottom of the page this work is saved. The receptacle provides a regular terminal block, and it is necessary only to connect the wires of the same polarity (say black wires) under the screws on one side of the plug. The white wires then are connected similarly on the other side. This type of wall re- ceptacleisvaluable to the home worker who is without a soldering outfit—Haro.tp P. STRAND. The new branch block plug wall receptacle. POPULAR SCIENCE MONTHLY PRESI* - The Man You’d Like to Know Healthy looking —well groomed, of the out-of-doors per- haps. This man has learned that Williams Shaving Cream can help—mightily—in keeping his Face Fit! The Williams lather, Standard for 90 years, for the clean shave, the quick shave! Cool as morning. So mild that fam- ous hospitals use it to wash the skins of new born babies. The Williams lather is known for its extra moisture. Satu- rated with 10% more moisture than any other that we know of. No atom of doubtful dye in Williams. Uncolored. Altogether pure. Ae Small wonder then, the drug clerk will tell you, “Ob, yes, sometimes they change....... but they all come back to Williams.” Then a dash of Aqua Velva. Scien- '§—_tifically blended to give proper care to the newly shaven skin. Gives a happy ending to the shave. That’s where shaving happiness belongs. And its fine effects last all day. Lose This Have you tried Williams Shaving Liquid? Very new! Ask your dealer. THE J. B, WILLIAMS COMPANY GLASTONBURY, CONN.—MONTREAL, CANADA Just notice the fine skins of men who use Williams SHAVING CREAM AA, Aer os Sewage Seta + aT ry Sean eae atin ah intl Ry ih j"

Page 126

Circular Saws for home work- shop rigs N? matter what make sawing outfit you use in your work- shop, a Simonds Circular Saw ° will stand lots of grueling ser- vice and give you results that exceed your expectations. Simonds Saws are made from the toughest steel known — heat-treated steel, specially tem- oy to hold cutting edges. hey stay sharp; they are fast cutting and accurate. Every Simonds Saw is an excellent specimen of fine workmanship. Leading manufacturers of portable rigs and home electric outfits will supply you with Simonds Circular Saws. Look | for the name Simonds. Free booklet on woodworking saws sent on request. Write for it. SIMONDS SAW AND POPULAR SCIENCE MONTHLY New Toy Model of Racing Seaplane sped model airplanes, copies of real ships of the air, can be made from scraps of soft wood, a few lollypop sticks, and some thin sheet metal. The plane illustrated is one of the most modern of aircraft—the high-speed seaplane. White pine is probably the best wood for the construction of the fuselage, pontoons, wings, and exhaust pipe, but any soft, straight-grained wood will serve. The struts and wing plugs are made from lollypop sticks, and the propeller and tail 3 ‘ LOLLYPOP STICKS FOR STRUTS LINE x CELLULOID WINDSHIELD 3 4 5 ° 8 Assembly views of the toy racing seaplane. The propeller and tail units are made of thin metal. unit are cut from thin aluminum or other thin sheet metal. The windshield, in front of the cockpit, is made of thin sheet celluloid, or of metal if the celluloid cannot be obtained. Make the wings in one piece from a 4 by 2 by 7 in. blank and cut the piece in | half after it has been brought to shape. The fuselage and pontoons can be painted a light blue, the wings and tail cream, and the propeller and exhaust pipe black.—DonaLp W. CLARK. Hints on Applying Paint on Metal Surfaces UTTERS, downspouts, and the like should not be painted until particu- lar care has been taken to remove all rust, scale, and dirt with a wire brush, putty knife, and sandpaper, and by scrubbing with kerosene, if necessary. It is impor- tant to remove all rust, for rust will eat its way through the paint. New galvanized iron and tin is always covered with a greasy film, to which paint will not adhere properly. The surface should be washed thoroughly with vine- gar, which will remove this oily substance. For the first coat, red lead or some other metal protective paint, or a specially pre- pared galvanized iron primer, should be used. The following coats may be of any _ outside house paint of the desired color. PRODUCTION CONTROL FROM YOUR OFFICE Bring machines—in effect—right into your office to tell you what they’ve PRODUCED. Watch their performance from where you sit, as registered on Vee- der-Root Magnetic Counters. See which machines—at any minute—are running, or idle, or producing too little. Get the rec- ords by wire from any remote point in the plant. J be Mechanical contacts on ma- chines in the shop make and break the electrieal circuits which operate the counters over your desk. Your regular lighting cir- cuit supplies the current. (Also counters to operate on storage battery.) Ask for new Catalogue of Counters for all machines and development-work, =—[IOOT incorPoraren HARTFORD, CONN. OFFICES IN PRINCIPAL CITIES: WRITE OR PHONE His ‘SAX’ set a million feet in motion! You, too, can thrill happy hearts and set feet into joyous action— ) with a Sax. You can have fun, be popular in lodge, school or church, and earn money on the side. Ba True-Tone Saxophones are easiest to learn, easiest to play. Simplified key arrangement makes fingers fallinto position naturally. In- sures rapid fingering and quick maswy of the Sax we wags — crohestrasana ae in ys. # top Easy to pay. A little down, then pay as a gulag. Write w be fee free catalog and details co BUESCHER BANOINSTRUMENT CO., 513 Buescher BI, , lar, a, SHAVE YEAR with ONE BLADE Just think of shaving 365 times with one blade. . . that’s exactly what a man did that uses the famous KRISS: KROSS STROPPER 11 seconds each morning. You can do the same thing. KRISS- KROSS peetenge the life of blades months and years. It employs the famous diagonal flip-flop stroke used by all master barbers. Send the coupon and learn about our FREE RAZOR offer, get de- scriptive literature. AGENTS are making by money selling KRISS-KROSS . AGENTS check bottom line of coupon f interested in agents proposition. 3 ee eee KRISS-KROSS Cor Dept. E-244 1418 Pendleton Ave., PA Louls, M Mo. Without obligation please send me full description of KRISS- KROSS STROPPER and FREE RAZOR OFFER. MTTITITIT TT TT iT Check here if i din b representative. ee 4 ere- ge- Gatesbu: Lad Ranens @© This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8.

Page 127

May, 1930 Baits Modernistic Worktable The top raised to show the remarkable inlaid design made from fourteen California woods. HIS beautifully inlaid modernistic worktable was built by A. L. Brown, of Paso Robles, Calif., from plans given in an article “Sewing Table in Modern Style,” by H. J. Roskyl (P.S.M., Apr. 29, p. 78). The cabinetwork and the in- laying were done entirely by hand from trees and shrubs grown in the vicinity of Paso Robles, the wood being cut green and sawed from the rough. The top, pedestal, and base are made from two contrasting woods—manzanito and what is commonly known as Cali- - =. a” A. L. Brown, of Paso Robles, Calif., built this table from PopuLar SciENCE MonrHLy plans. fornia holly. The inlay consists of four- teen varieties of wood. The finish is clear brushing lacquer, which brings out the natural beauty and figure of the grain of the different woods. So clear and smooth is the finish that it seems to have an odd attraction for all those who see the piece for the first time. WHEN assembling machinery or ap- paratus which has the head of a bolt or machine screw on the outside and the nut in an awkward position on the inside, the nut can be started without much trouble provided you can reach the place with a finger. Wet the finger tip with shellac, let it become tacky, and stick the nut on the shellac. It is then possible to reach in and hold the nut until the screw has been started.—ARNOLD W. REITZE. ee POPULAR SCIENCE MONTHLY — 125 » Jordanoff ~ USES Carborundum EG.U.S.PAT, ° BRAND Sharpening Stones “IT have used Car- borundum Brand Sharpening Stones for many years to sharpen my tools— An Aviator-Mechanic must do accurate pre- cision work, and his tools must be kept in the best con- dition possible— My tool kit has always included a Carborundum Stone. As an abrasive, I have found Carborundum to be fast cutting and always produces a clean, sharp job.” ASSEN JORDANOFF —_SCo-=, HUS, a famous aviator, pilot, de- signer, craftsman, joins the army of craftsmen now depending upon Carborundum Brand Sharpening Stones to keep edge tools keen and clean-cutting. These stones are made of genuine Carborundum Brand Silicon Carbide, a manufactured abrasive—hardest, sharpest, quickest-cutting material known. FOR SALE BY HARDWARE DEALERS EVERYWHERE The CARBORUNDUM Company Nracara Fa tts, N. Y. Canadian CARBORUNDUM CO., Ltd. Niagara Falls, Ont. CARBORUNOUM IS THE REGISTERED TRADE MARK OF THE CARBORUNOUM COMPANY FOR ITS PRODUCTS ER EATEN SE Send for This Book jase. * 32-page Booklet, ‘‘HOW TO SHARPEN - WOOD-WORKING TOOLS—P1” is yours Free— Mail this request Name @Orhis seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8.

Page 128

126 POPULAR SCIENCE MONTHLY ~

May, 1930

Wet CELLARS MADE Dry from the Inside!

AMP musty cellars are unsanitary, a danger to health and a poor place to store valuable material. Where water or moisture seep in through cracks or porous spots in the floors or walls, you can make and keep your cellar dry and sweet—a fit place to work, free from odor, mold and rust—by filling the cracks and coating the moist surface with Smooth- On No. 7. This is the one practical waterproof- ing that you can apply yourself, easily, from the inside, to , |< wet or dry ment with Smocth-On No.7 surface and with every assurance of thorough water- tightness, even in the wettest seasons. Excellent also for patching concrete floors, waterproofing garage, stable and washroom floors, brick walls, cisterns, septic tanks, watér troughs, fountains, fish ponds, swimming pools, manure pits, etc. About 25 pounds of Smooth-On No. 7 are | required for each 100 | square feet of surface covered, and no ex- perience is mecessary. Complete instructions on the package.

HOME » Auto REPAIRS Get Smooth-On No. 7 in lor 5-1b. can, or 250r100-1b. keg and Smooth-On No.1 | in7-oz. or 1 or 5-lb. can. At any hardware store, or if necessary from us direct.

Write for FREE BOOK The Free Smooth- On Repair Book will show you how an as- tonishing number of re- pairs are easy to make, and by doing the work yourself you make big sav- a. Mail the coupon for a free copy.

SMOOTH-ON NO 7 SMOOTH-ON MFG. CO., Dept. 58. 574 Communipaw Ave., Jersey City, N. J.

Please send the free Smooth-On Repair Book. Quote price on..... Ibs. of Smooth-On No. 7.

EEE, ere eee eee ee sewsess MEM dee wncdvalveedyecndasngsdeencuadeesesé Return this coupon for FREE copy of Booklet |

Perforated Metal Sheets Useful in Craft Work ERFORATED metal is a material which can be used in many ways by home workers. It may be bought in sheets of steel, brass, copper, bronze, zinc, lead, tin, and aluminum and in almost any size and in any thickness from .03 to | .375 in., although, of course, only the lighter weights are useful for amateur work. The perforations are of many

METAL PANELS PERFORATED META _e Design for a chest with decorative aluminum panels, and three patterns of perforated metal.

om shapes, of which three common varieties are illustrated. The lighter metals and sheets may be used as panels for fire and porch screens, | for radiator cabinets or shields, and for plant boxes, waste baskets, chests, and wood boxes. As a panel for the chest illustrated, for example, aluminum, with its silvery texture, if backed with well-chosen silk or other material, would make a light and _ distinctive looking storage place for linen _ or bedding.—Davip WEBSTER. Repairing a Water Tank S™ ALL leaks in hot water storage tanks can be quickly repaired in the manner illustrated. Measure the distance around the tank, add 1% in. to this, and then cut a strip of galvanized iron to that length. 1"x 4" PATCH OF RUBBER PACKING OVER A LEAK

HOT WATER TANK A narrow galvanized iron strap holds a small patch of thin rubber over the leak in the tank. Drill a %-in. hole % in. in from each end of the strip, bend the ends up so as to form 1-in. ears, and bolt it around the hot water tank after covering the leak witha 1- by-4-in. piece of rubber cut from an old inner tube. Draw the bolt up very tight.—Wit1am A. Cerow.

oA RE ae — ee —" ~ WHEN THIS BOAT COMES PUT-PUT PUTTING HOME ... THERE'LL be a warm frying pan ready. For it’s a sure bet there’ll be fish to fry when you go in a motor-driven “Old Town.’”? You motor in an “Old Town” to your favorite spot . .. you're | there in time for the fishes’ breakfast . . . and they’re back in time for yours! “Old Towns” are wonderfully fleet and sturdy craft. Durable—built for heavy loads, but easy to handle. With sponsons if you like. Free catalog shows and prices many models — rowboats, din- ghies, all canoe types; big, fast, seaworthy, all- wood, outboard boats for family use, and speedy step-planes. Write today. Old Town Canoe Co., 1155 Main St., Old Town, Maine. “Old Town Boats” 25 POWER $1 GERMAN POCKET MICROSCOPE

A marvelous German 25 power microscope, size of pencil, En- larges diameter 25 times, area 625 times. Fine lenses give ex- | tra. ares field and great light. Only 4 3/8 inches x 3/8 inch; | weighs but one half ounce. Used in schools and colleges t he } out the country. Fine for biology, geology, botany, nature study, examining stamps, finger prints, insects, cloth, metals, photographs and thousands of other things. uipped with handy fountain pen clip. -S0-GOX, 1 1/2 oz. $4. $1 prepaid. Money back guarantee. Discount for 6 or more BINOCULARS ,27%:20S'se¢%,4 t J ! assortment in America. Catalog gives all information how to choose the best for your individ: needs at the LOWEST PRICE. Try America’s Leading Binocular House First DuMaurier Co., Dept.305, Elmira, N. Y. The Woodworking Equipment You Need © Above All Others— H&A SAW TABLE The Tool of Many Uses Use it for ripping. cross-cutting, mitering. grooving, rabbeting or dadoin A sturdy, powerful, large capacity machine that will handle wide ma Accurate. speedy reasonably pri: Equipped with tilting fence for bevd sawing; 4 or % H.P. motor; ball bearing spindle. Write for catalog @ woodworking tools. HESTON & ANDERSON 805 Kirkwood Avenue, Fairfield, lowa 30 Devs Free Trial on all MEAD Bicycles ER Models now ready for delivery direct from our factory. Astonishing new prices an . Do not buy until you get them. RIDER AGENTS WANTED to ride and exhibit sample. Save big money. Many models, styles. Tires ree. lanes. —q it at usual prices. ayments. Write for our marvelous prices and terms.

LSO, 20 cabinet and 20 inlay, $1.75 —or your choice $1.00. ._ Sets labeled and postpaid.

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

. ee ee ae . 1%

|

Page 129

, 1930 May, 1930 POPULAR SCIENCE MONTHLY 127 Neat | Neat Smoker’s Rack for Holding Pipes | MOKERS who prize their pipes can display as many as seven of them in | the compact and ornamental rack shown below. It can be constructed with few tools and from any odds and ends of wood. : The plywood back A measures % by | 734 by 14 in. and is braced with two 3 by The New NON-SKID z: Screw Driver x DRIVES =a SCREWS The rack can be made from scrap pieces of wood and lacquered to suit the individual taste. EASIER 34 by 7 in. hardwood cleats, which are fastened with flat-headed screws. Draw center lines on the top and bottom surfaces of a 134 by 2 by 13 in. piece of stock for the roof B. Beginning in the | ts ht te 0 dee middle and working out to both ends, lay OU k h isl 46 da out the centers for the 1 in. diameter holes | a ee a as indicated in the drawing at the bottom memes yi wae wn 38 37 nd to draw a rusty or bat- of the page. The base, which is 34 by 234 by 13 in., tered screw from any kind of wood! should have seven recesses cut to a depth That's why tool users are demand- of 34 in. in its upper surface. These can \ ing the new Bridgeport Non-Skid best be shaped with a chisel. Screw Driver! You don't have to _ The columns are 1 in. square and 5% be a Samson to drive screws with in. long, including two pins on the ends, the Non-Skid! No pushing, no | C——) || * eed which can be cut easily with a pocket- ubitiinn-ymt: tian a | knife. These pins are 34 in.-long and % ig ‘ rs— pag mn 5 ” —- Skid! The ribbed blade grips the | Assemble the top, bettom, and two screw like a gear in mesh. - Turns E | columns, and fasten the columns by battered and rusted screws like they driving wooden wedges into saw cuts in A were new. Turns greasy screws that tig the tops and bottoms of the pins. Attach give smooth-blades a “sleigh ride.” the back with brads and glue. The Drives screws easier, quicker, safer. In finishing, the writer used red lacquer for the inside of the holes and the recesses . in the base; dark blue for the top and RIBBED BLADE : bottom; black for the columns; and dark 3 Styles—All Sizes brown for the back. In the center of the Prevents. Slipping No. 1—Blade runs clear through i a exposed back a decalcomania transfer was handle—4”, 50c; 6”, 60c.. No. 2—: And lasts longer because it won't slip! placed. Small hand painted decorations Blade, handle and ferrule riveted were placed on the front faces of the two securely together—4”, 35¢; 6”, 45¢. columns.—WI LIAM C. CLARK. No. 3—Shockproof up to 18,000 volts—4%"’, 45¢;6%”, 55c. If your dealer is not yet supplied, order BOARD An He x 7% x! ry bA. N © direct. Just use the coupon below. Leerpiiiti: TR r]Roor a” aoe at * | | CLEATS 56% %4 x74 | ol | TRADE MARK bf ¥-- + -- tT eT Cr cra] = pe THE CHOICE of MEN WHO KNOW TOOLS FRONT VIEW — | GOIN ee ee ee ee ee ee ae ee eee eee ee be ae THE BRIDGEPORT HDWE. MFG. CORP., BRIDGEPORT, CONN. panes I am enclosing (in stamps, money order or check) for which send me postpaid the following (amount ) — APs nk Gas SF I Bridgeport Non-Skid Screw Drivers: SOOO ONT uj ul are eM . ‘ : (state quantity, screw driver numbers and sizes). fl TOP view BASE %' x 2%'x13 . 4 . i PIII oko. 5 é road c ACESS «0's HOCR Swe RE Sy on 4:3:0:6.0o 5s c0e Rke oe beeeted baae we D Dimensions of the pipe rack. The pins on the columns are % in. long and % in. in diameter. — ON ia cs saicn ake scien sth ieee whale aes ae ce GU os ciiviicsinsnasgatiabess

Page 130

128 MEN WHO KNOW STEEL PREFER THE VALET —MEN WHO KNOW FACES PRESCRIBE IT fe." ge _— a Rs kysicians in the worlds largest hospital agree the new VALET BLADE is easter on the face NE physician after another in Chicago's famous Cook County Hospital prefers the new Valet blade—definitely and out- spokenly. Experience has convinced these authorities that the new Valet is easier on the face—a valuable protection against infections. It glides lightly—smoothly— without irritating the skin. We asked: “Will it prevent skin troubles caused by improper s aving?” Nine out of 10 answered, “Yes.”” Dermatologists every- where prescribe the new Valet for the cor- rection of such conditions! This remarkable blade is built by advanced precision methods for use in the Valet AutoStrop Razor—the only razor that does not require removal of the blade before or after stropping, shaving or cleaning. All dealers now have the new Valet blade in stock. AUTOSTROP SAFETY RAZOR CO., Inc. 656 First Ave., New York Also Toronto, London, Paris, Milan, Rio de Janeiro The NEW VALET AutoStrop BLADE POPULAR SCIENCE MONTHLY Painting Simplified by Correct Use of Solvents By BRUCE BRIGHTON pace no one thing is of greater help to the home painter or does more to make painting an interesting and profitable occupation than to realize that the various paint, varnish, and lac- quer materials have certain solvents, through the proper use of which paint may be removed from any surface or may be thinned to a more satisfactory working condition for application. Fol- lowing is a brief description of these _ solvents, which may be readily obtained in every locality, together with a sum- mary of their uses and advantages for different purposes. One of the most extensively used paint solvents is turpentine. This is obtained from pine and other cone-bearing trees, the greater part of the world’s supply | coming from the pine forests of the South Atlantic states. A fluid extracted from 44 An understanding of solvents makes painting aneasier problem. the tree by cutting an incision in the bark and sap wood is distilled to produce the commercial spirits of turpentine. Turpentine may be used for reducing any paint, varnish, or enamel of the oil type. It not only reduces the paint mixture to thinner consistency but, as it evaporates slowly, it makes quick- drying materials easier to work, since it slows up the drying. Turpentine may also be used for general clean-up work of all kinds. It is not, however, a powerful enough solvent to remove paint that has become thor- oughly dry and hardened. It is used extensively for cleaning grease and oily furniture polish preparations from sur- faces to be refinished; also for removing wax from floors, woodwork, and furniture before refinishing; and for washing off the surface after the use of paint remover. In this process, the surface should be scrubbed out with a vegetable or scrub- bing brush dipped into the solvent, and then sandpapered until dry. (For the foregoing-purposes, however, alcohol will be found more satisfactory, as it cuts grease and wax more effectively, and leaves the surface in better condition for refinishing.) Turpentine may also be used for cleaning spattered or daubed woodwork, wiping off spoiled or faulty work, removing paint from clothing, rugs, and for cleaning the hands. In ' | May, 1939 e” NEVER + MIND! Savogran Crack Filler will fix it! Hotes in plaster, cracks in wood, broken fur- niture, loose castors—fix them quickly with Savogran Crack Filler. After painting or stain- ing, the damage disappears for good ! Householders, painters, carpenters, industrial users, are turning to Savogran Crack Filler be- cause it won't shrink. It’s easy to use, per- manent, and inexpensive. At hardware and paint stores everywhere! Made by the makers of Painters’ Savogran, the heavy- duty cleaner that cleans dirt and grease like magic, re- news hard paint brushes, removes paint and varnish — saves time, money, and hard work. Try it. Big One-Pound Can 30c Savogran Crack Filler—35-lb. all-metal pail $7.70; 5-lb. can $1.25; 1-lb. can 30c. Economical. No waste. SAVOGRAN COMPANY india Wharf, Boston, Mass. SAVOGRAN CRACK FILLER WILL NOT SHRINK! of the Flyi Cloud. Constitution, Galleon, Misslesippi iver 5 b eign of the Seas, Bluenose, Mayflower and many others. Also special construction sets for racing sail boats, power boats, model steam engines, propellers, ete.. and fine tools for the model maker. Our large 48-page photographically illustrated booklet contains valu- able information and hints for building ship models in addition to prices and full description of the above articles. Many people only slightly interested in models have become greatly enthused upon re- ceiving this booklet. _ A copy will be sent postpaid upon receipt of 15 cts. (coin preferred). ) Model Ship Supply Co., Dept. N, Mineola.N.Y. Tool Chests For Exacting Mechanics The right chest for Ma- phiniote an‘. Toolmakers Free Catalo Send for it today. H. GERSTNER & SONS 677 Columbia St. Dayton, Ohio vase INVENTIONS PAY Sy, Millions have been made from ideas properly Gp developed and protected. by inventors. One of the first steps is the development of a practical working model. Send us rough sketch or model of your idea. We will submit complete report backed by 30 year® experience in model making. Confidential service. Modern equipment. Bank references furnished. FREE let “‘Making Inventions Pay.” CRESCENT TOOL COMPANY, Dept. B, Cincinnali, 0. v Siri The Midget “*Five-in-One”’ Slide Rule is a combination M ~~ ric . yo AW isc Silae Male it will instantly Free CO.. Stuart. fiorida A definite program for getting ahead financially will be found on page four of th's issue. tio an she

Page 131

» 1930

iEEAH wa] I] 5s BE : eS oS: =scma Nickeled steel adjustable frame, pistol snp. handle: Non-Breakable or the New Silver Steel Bine-End Blades. ATKINS CIRCULAR

Circular Rip, Cross-Cut and Mitre Saws for fast, accurate work on any machine. a Bip. “ae SRRINS ‘ BAND SAWS J. Silver Steel Narrow Band Saws for smal! machines.

ATKINS GROOVER OR DADO HEADS The simple, easy way to cut smooth 4.4 even grooves from %’ to 4" width.

Made of Silver Steel; for large or small workshop planers, jointers, shapers, etc. Booklets on Saws Sent You FREE Mail Coupon © This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. MONTHLY

129 Cutting is FUN with These Saws OU’LL have more FUN and less work, in cutting wood or metal, if you use AT- KINS Saws. They save you time, energy and money—cut with amazing speed and ease— because they are made of the world-famous “Silver Steel,”’ used only by ATKINS. They take a keener edge, cut faster, run easier, stay sharp longer, need less filing, and outlast ordinary saws. That’s why ATKINS are the favorite saws with home-craftsmen, just as they are with finest mechanics, and in great factories and mills the world over. For cutting any metal, the quick, easy way is with the new ATKINS Silver Steel Blue-End Hack Saw Blades. They cut TWICE as fast as any old-style blades and last SIX times as long. Try one on your next metal-cutting job and see the big difference! For fine wood-working, there are ATKINS hand saws and small saws to help you do faster, better cutting. Our No. 2 Back Saw, for example! Ideal for cutting miters, grooves, and doing fine cabinet work. Also, compass saws, coping saws, keyhole saws, files and saw sets, Scraper blades, etc. ’ And for power sawing, ATKINS makes cir- cular rip, cross-cut and miter saws to fit all outfits. Also, Dado Heads, narrow band saws, grinding wheels, and machine knives. Ask your Hardware Dealer for the ATKINS Saws you need. If he cannot supply you, write us. booklets shown below. Send coupon for the four helpful They’re FREE. E. C. ATKINS & CO. Est. 1857 4285S. rene S INDIANAPOLIS, Picose oye me the four Saw Rice

Page 132

a see a

To sp

Stealing second ... racing in to field a bunt or rob the batter of a safe hit ... nothing will stimulate your body to its final flash of s al like the comfort, freedom and security of a dependable athletic supporter. A game of science and skill, base- ball is also a game of sudden risks and chances. Sliding, leaping or diving, you can trust Bike or Pal to guard the vital ... but least rugged ...zone of your body from awkward accidents and crippling strains. Bike is the professional, college and school favorite, everywhere. A sim- ple, one-piece, all-elastic supporter, its comfort and sturdy strength have made it the safety standard of athletes, coaches and trainers for 55 years. Easy to wear. Easy to wash. Easy to buy, too, at 50 cents. Pal is a still finer supporter, with exclusive patented improvements that provide super-service and pro- tection. Priced from a dollar up. Sold by druggists and sporting goods dealers everywhere. BIKE and Pal [C BAUER & BLACK) DIVISION OF THE KENDALL COMPANY - New York + + Toronto Chicago - (ser eed up your game POPULAR SCIENCE MONTHLY

any of the new quick-drying lacquers, the use of lacquer thinner is an absolute necessity. This is essentially a product of the alcohol group, being, in brief, alcohol treated with acetic acid to produce a water-white liquid having a bananalike odor. FACQUER thinner is a very high- powered solvent, and, asit will quickly cut into previously applied finishes that have become thoroughly dry and hard, much care should be taken in its use for general clean-up work. It is, however, the ideal material for cleaning lacquer brushes as well as for cleaning the hands after the use of lacquer or for cleaning spilled or spattered lacquer from clothing and rugs. It may be used with thorough satis- faction for removing an old lacquer finish from any surface where so desired for refinishing. Being also a powerful solvent | of the oil type paints, varnishes, enamels,

and stains, it is sometimes used for remov- ing painting material of various kinds that have become hard, as well as for cleaning paint and varnish brushes. Naturally, lacquer thinner is designed primarily for reducing lacquer, and should be used for this purpose wherever thinning is found to be necessary. None of the foregoing solvents are sufficiently powerful for the complete and clean removal of old paint or varnish finishes so that the surface may be properly refinished. For such require- ments, an extremely high-powered, slow- drying type of solvent must be used. While different materials may be used for this purpose, some of them will burn or otherwise injure the surface for refinish- ing; others are so high-priced as to be impracticable. The removers in most general use at the present time are of the benzol.type made chiefly from benzol, which is a coal tar product with certain other materials added and so treated as to prevent rapid evaporation. Most of thé products sup- plied by paint stores under the name “paint and varnish remover”’ are of this type. These paint and varnish removers are ordinarily applied to the surface and allowed to stand for a few moments to soften the old finish, after which the old coatings are scraped off with a putty knife. As previously explained, it is all- important that the use of paint and var- nish removers be followed by a thorough wash-up with turpentine, gasoline, ben- zine, or alcohol (preferably alcohol), and a thorough sandpapering to clean off all remaining deposits of the paint remover, which would otherwise prevent the drying of following finishing coats. Paint and varnish removers may,also be used for cleaning brushes that have become hard- ened, as well as for softening and remov- ing dry, hard paint from clothing, rugs, and other materials. WORD or two more about the use of solvents for thinning purposes, as there are a few general principles which, if observed, will enable the home painter and decorator to use them cor- rectly and with the assurance of the best possible results— In the first place, it-should be fixed in

Ornhis seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. May, 1939

OUTBOARD MOTOR BOATS—For Every Pur. pose and wey A Purse == The very fastest and most seaworth Type, V Bottom and Sled T Boats for family use, and a strictly up-to-date line of Step Plane Racing Models to choose from. Rowboats $48.00 and up— The most complete line ever offered, at real money. saving prices. Canoes $50.00 and up— Some all wood, others canvas covered. Light, swift; safe, strong and durable. Choice of man tinctive color combinations. ;

With or without Engine. Fast, handsome six pas- senger craft at money-saving prices. CATALOG FREE — SAVE MONEY — ORDER BY MAIL Please state the kind of boat you are interested in (35) ———> TWO LARGE FACTORIES <————— THOMPSON BROS. BOAT MFG. CO. 219 Ann St. ( Write to 119 Elm St. wisconsin \PitherPlace} = New york

Mill-cut lumber and easy construction plans save you 40% of labor. Mrs. A. A. Bishop moved into her home one month after starting. Jay Miller says he had his home built while many would be still fussing with plans. Many do work themselves and save $288 to $1000 and more on materials and labor. _ FREE.-Big New Catalog Shows beautitul, life-time homes from $392 to $1558. Price includes all highest quality lumber cut-to-fit, doors, windows, stairs, high-grade interior woodwork, lath, shingles, hardware, glass, paints, nails, etc., complete, Porch included. Time payments if desired. Materials fully guaranteed Write for catalog today. Homes, Lewis Mfg. Co., ept. 13-E, Bay City WE PAY FREIGHT |

“WOODWORKING SHOP FOR INCOME OR HOBBY j) FIVE FOOT WORKSHOP INCLUDES: Planer, Circular Saw, Lathe, Disc Sander, Buffer, Grinder, Drill Chuck, Motor, V Beit Pulleys, Sub Base, Cable with Plug. Under the magic of Workace Electric Woodworker raw lumber is easily converted into useful and valuable articles. Manor ( oi boy willenjoy Workace.Sim) a intoelectriclightsocket.$9. wo » will bring it. Send now for offer. J. D. WALLACE & CO. Wilcox St. at California

WoRKACE électric WOODWORKER

Page 133

\Y, 1939

May, 1930

mind that where one thing is gained, something else is sacrificed in some measure. Therefore care should be taken to keep a balanced material. Remember that while enough is good, too much may be detrimental. EI us take, for instance, the thinning of a flat wall paint with turpentine. Suppose the material is too heavy for easy brushing and shows brush marks. Some turpentine should be added, which will bring about easier brushing with freedom from brush marks. However, the tur- pentine will reduce the hiding power of the paint. Judgment should, therefore, be used in the thinning of paints so as not to reduce the covering power to too great an extent. Turpentine tends to flat the finish, or in other words to reduce the gloss, and therefore only a small amount should be added to enamel, varnish, or other mate- rials where a gloss finish is desirable. As a rule, thinning of these materials is seldom necessary, unless they have be- come thickened from standing. In the use of varnish, however, there is one exception to this general rule—first-coat work on new wood. Here ten to fifteen percent of turpentine should be added to help penetration into the new wood. On the other hand, the flatting nature of turpentine may be just what is wanted at times, and the addition of a small amount may be desirable to reduce the gloss of some over-glossy material. In outside house painting, a slightly different set of principles is involved, on account of exposure to the weather. Here one of the main functions of a solvent thinner, like turpentine, is to help penetra- tion of the paint material into the sur- face. An ample amount of turpentine always should be used in the first or prim- ing coat on new wood, especially oily, hard or sappy woods; also in the first refinishing coat on two-coat repaint jobs. Some turpentine should also be used in the second coat of three-coat new jobs, to make this coat an extremely hard one. It should be remembered, however, that an excess of turpentine will cut down the body of the paint too much, and impair durability. For the last or finishing coat, very little, if any, turpentine should be used, as it will impair both the durability and appearance of the finish. Where the material is too heavy in consistency to permit satisfactory brushing, raw linseed oil should be used for thinning this coat. Using a Paddle to Mix Paint Thoroughly Te OBTAIN good results from any paint, it must be thoroughly mixed. Otherwise, the heavy pigment will go to the bottom and the top part of the paint will be too thin to give good results. A container of paint should be stirred toa uniform consistency immediately before and at intervals during application. Stirring round and round does little good. <A flat paddle should be used, Starting with the end of the paddle at the very bottom and bringing it up through

-the paint with a turning, twisting motion. —_—_____

POPULAR SCIENCE MONTHLY 131

ont blame the Floor § for your ~ neglect / O; course a floor like every other surface subject to wear must have care. Sometimes this is neglected and the floor together with your repu- tation suffers. That’s the reason ,you should finish and preserve floors with anize FLOOR ENAMEL __ edi. The modern quick drying enamel finish Look around for old floors, new floors, indoor floors, out- your home: door floors and woodwork. J te lol Brushes on like cream, flows to perfect your guests ao; . Kyanize puls beauty in every room smoothness, dries hard in six hours, is — waterproof and comes in twelve dashing wy colors. Decorate Floors in New Patterns: With the Kyanize Ro.tpart System and Floor Enamel you can easily express your own taste in handsome floor patterns. Ask your dealer today. WRITE FOR BOOKLET Send us name of your paint dealer and receive a copy of our newest booklet in colors entitled “Dream Floors.” Write today. BOSTON VARNISH COMPANY 356 Everett Station, Boston, Mass.

Page 134

132 “Learn to Fly in a Glider’ Says Frank Hawks Here is what Captain Frank Hawks says about gliding: “First, it teaches the basic principles of flight correctly. Secondly, it is safe. And third, it isa great sport.” Why not form aglider club so you and your friends can learn the fundamentals of flying? The Detroit Gull—built by Gliders, Inc., pioneer manufacturers of motorless aircraft in the United States, offers a proved primary type ship, ideally designed for students of gliding. Group ownership of a Detroit Gull is inexpensive—the initial cost is low and the upkeep practically nothing. We cordially invite you to write for glider club information and for our illustrated folder on the Detroit Gull. The DETROIT GULL 5485 with safety belt

GLIDERS INC., Division of DETROIT AIRCRAFT UNION TRUST BUILDING, DETROIT CHANIN BLDG., NEW YORK ROOSEVELT BLDG., LOS ANGELES RYAN AIRCRAFT CORPORATION LOCKHEED AIRCRAFT CORPORATION PARKS AIR COLLEGE, INCORPORATED PARKS AIRCRAFT CORPORATION EASTMAN AIRCRAFT CORPORATION AIRCRAFT DEVELOPMENT CORPORATION BLACKBURN AIRCRAFT CORPORATION MARINE AIRCRAFT CORPORATION GROSSE IIE AIRPORT, INCORPORATED AIRCRAFT PARTS COMPANY, INCORPORATED DETROIT AIRCRAFT EXPORT CORPORATION

POPULAR SCIENCE MONTHLY

May, 1930

Die Shapes Model Tackle Blocks NIFORM tackle blocks made of fiber for use on ship models can be quickly shaped with the steel die illustrated. The die is made from a % by 1 by 3 in. piece of tool steel. Cut the die holes to the size and shape of the blocks that are to be made. Drill two small holes at right angles to the die hole and slightly above its center. These holes serve as a drill jig for the sheave holes. Temper the working ends of the die and it is then ready for use.

DRIVING A FIBER STRIP bh THROUGH DIE

HARDENED

, A STEEL i" HOLES i f DIE (SHAPE or -(_) . pws. BLOCKS) > ---=i_ J — —3-[ iF \ «__! one tant a1 | ot. ; H ort ee } Ss way ‘¢e SMALL HOLES FT (USED AS DRILLING JIGS) Ty LONG om I) ” (| ” Ys2 DIA. it COPPER WIRE

Se a Yuie GROOVES Dimensions of the steel die and sketch showing how it is used. Note proportions of the block. tendency to split when the sheave holes were drilled. Fiber answers the purpose | perfectly and can be purchased at any dealer in machine shop supplies. Cut the stock into rectangular rods 6 in. long and of a minimum cross section. Taper one | end of the stock so that it will fit into the | die hole, and drive it through with a hammer (see illustration). After shaping sufficient stock in this way, pass the fiber through the die again and cut off the | blanks to the proper tength with a fine toothed hack saw. Place the blocks back in the die and drill the sheave holes. The sheave grooves and grooves for the straps can be cut into the surface of the pulleys with a three- cornered file. The straps and hooks on the blocks are formed from ‘%-in. copper wire. Cut the wire to the proper length, fit it in the side grooves, and wrap it around the block in the manner shown. In making upper blocks that are to be fastened to the end of the rope or fall, it will be neces- sary to provide loops at both ends. When the blocks are completed, re- move the sharp corners with sandpaper and dip the entire pulley in shellac or varnish.—H. L. WHEELER.

ia e

While tackle blocks are generally made | of wood, it was found that wood had a OU will be doubly welcome every. where when you learn to playa Conn, Chances to join a band or orchestra, to * travel, to make extra money. Conns are the choice of Sousa and the world's gi=at- est artists. Easiest to play. Recommence4d to beginners for quicker progress. FREE TRIAL, EASY PAYMENTS on any Conn. No matter which band or orchestra instrument interests you most, Conn will send you a special booklet on that instrument giving valuable facts. C.G. CONN, Ltd., 542 Conn Bldg, Elkhart, Ind.

BAND INSTRUM

— Write for FREE BOOK >» > Mention Instrument < «

LOW PRICES GOODRICH-GOOD4 YEAR Firestone - U.S. AND OTHER TIRES

| |

CORD Tires BALLOON ‘Tubes | Size Tires Tubes 30x3 $2. $1.00 | 29x4.40$2.30§1.10 +25 1.00 | 29x4.50 2. 1.16 31x4 ° 1.15 | 30x4.60 2. 1.20 4 ° 1.15 | 30x4.96 2.' 1.35 4 x" 1.15 | 28x5.25 2. 35 34x4 6 1.15 | 30x5.26 2. = 832x4 \. 1.45 | 81x5.25 3. 1 33x4 «20 1.45 | 80x5.77 3. 1.0 34x4! w 1.45 | 82x6.00 3.2 40 30x65 \ 1.75 | 83x6.00 3. 4 = ahs Fe | x 178 82x6.20 3. 1, 35: 4. 1, All Other Sizes DEALERS $1:00 deposit with pach tire WAN TED percent if ry full pa, air. Tires failing to give 12months servi l be replaced at half price. YORK TIRE & RUBBER COMPANY, Dept. 120 a Avenue Chicago, jilinois | jut LOFTIN-WHITE your Direct-Coupled AMPLIFIER with the ELECTRAD KIT Approved by the Designers

Wi 175 Varick St.. New York. N.¥. 2 © ELECTRAD - THREE PRACTICAL EDUCATORS! The Real Estate Educator The New Revised Edition, contains Questions and Answers; Brokers’ License Law; Dictionary of Words and Phrases in Real Estate and Construction; How to Appraise Property; Law of Real Estate; How to Advertise Real Estate; Legal Forms; Commissions to Agents; ‘‘Don’ts’”’ in Confracts, etc. 288 pages. Cloth. Postpaid $2.00. . The Vest Pocket Cushing Just out. An A. B. C. Guide to Parliamentary Law based on the highest authorities and adapted to gen- eral use—containing model speeches and toasts for all occasions. 128 pages, size 244x4% inches, leather- ette. Price, $1.00. The Vest Pocket Book-keeper and Short Cuts in Figures A simple and concise method of Practical Book- keeping with instructions for the correct keeping of books of account. How to take off a trial balance sheet and finally close and balance accounts. 160 pages. artistic leatherette............ Price, tpaid $1.00 POPULAR SCIENCE M gare 381 Fourth Ave., N. Y.C.

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

Page 135

mt cu ice “4 ere As aasskakesas Sod 1$ # and rds low ‘to ons zes. aw en- for .er- ok- : of nce May, 1930 POPULAR SCIENCE MONTHLY Woodworking Hints of a Veteran Craftsman By HENRY GEORGE ANY operations in the amateur M woodworking shop can be greatly simplified if the worker will apply a few of the short cuts and labor-saving methods used by the professional car- penter and cabinetmaker during his day at the shop. When driving nails or brads through one piece of lumber and into the edge of another, as when putting a box together, start the brads so that they will enter the edgewise piece close to the inside edge and on a slant that will keep them well within the thickness of the wood (see Fig. 1. In honing, grip the tool firmly with the finger tips only as illustrated above. | Fig. 3). This allows the full thickness of the wood in which to drive the nail in- stead of one half the thickness, as is the case when brads are driven straight down into the center. Another advantage of this method is that your nail or brad is not so likely to split the toppiece, being started farther back from the edge. In finishing work in which the joints between the various pieces show, work some glue into the cracks carefully with- out getting more on the surface than is necessary; then, with fine sandpaper and a block, sand over the cracks until the wood dust has completely filled them. When the glue has hardened, clean the work with fine sandpaper around a block. If your work becomes dented or marred, wet the depression and keep it moist until it has swelled up flush with the original surface. If the surface is filled with oil or varnish, as would be the case in finished wood, scrape and sand it so that the moisture can penetrate into the grain. When gluing up work on which it is impossible, because of the shape, to make a screw clamp hold, wrap the glued joint with heavy cord and tie it tightly. Do not stint the wrapping because each overlay increases the pressure. A slight film of oil on a cutting edge will ease a tool through old dry wood with- out chewing it and will allow you to con- trol the tool with greater accuracy. In driving screws into very hard wood, drop a little oil into the drill hole or draw the — Indian goes nautical, too! The new Indian Silver Arrow Out- board is a Class B motor embody- ing all the ex- perience Indian has acquired in 27 years of building small power plants. Power, speed, stamina—all you look for in an outboard, lus an ease of starting itherto unknown. se Pndlan'> AVER ARROW 133 itthe INDIAN TRAIL to Health and High Adventure 1+ 7 7 + NLY a sportsman appreciates a motor- cycle. No box of glass and wood for him . . . he wants to feel the sun on his back, the breeze in his hair . . . to watch the road slip beneath him, to see the blue sky above. Out in the open, to see all around, to breathe pure air, to venture into places no motorist can go— that’s sporting transportation. And it is no wonder an Indian is the out- door man’s choice—it snaps away like a ball off Babe Ruth’s bat... it slips through traffic like a clever quarter-back . . . it takes the steepest hills with the smoothness and grace of a pole vaulter . . . it skims the open road with the flash of a sprinter or throttles down to the smooth, steady pace of a cross- country runner. If you’ve never driven an Indian, go to a dealer for a demonstration . . . “kick” the motor over, settle down in the comfortable, springy saddle . . . feel the thrill of the power that throbs out of its big motor. Try iton the road . . . put it on the steepest hill you know . . . test it in traffic for snappy get-away—for quick, sure stopping. Then you will know why an Indian Motocycle is ‘The Sportsman’s Steed.” MOTOCYCLES INDIAN MOTOCYCLE CO., Dept. C-4, Springfield, Mass. Send me booklets checked INDIAN MOTOCYCLES ..qQ INDIAN OUTBOARD MOTOR 0

Page 136

Sa es La eceree eons

POPULAR SCIENCE MONTHLY NEW MODEL. SOUTH BEND LATHES

/ FOR THE 7 Manufacturing Plant Service Station General Repair Shop Engineering Shop P Machine Shop and Laboratory All on Easy Payments We ship any South Bend Lathe immedi- ately upon receipt of only 20 per cent of Catalog price. Balance in 12 equal monthly payments. Write for Time

ke

Payment Catalog.

9-in. x 3-ft.J unior Back t ee e ‘ Geared Screw Cutting Px ° oe SR ss Bench Lathe, with Sf C ountershaf t 169 we and Equipment ae “au ‘S soe ane aeeee Bed “ba . th Equipment od Size of Lathe ne Countershaft Silent Chain Se Weight Drive \ Motor Drive ~ i x3 490 Ibs $294.00 $398. < 11" x4’ 725 ibs 359.00 498.00 13” x 5’ 1110 tbs. 443.00 602. 15” x6" 50 Ibs. 543.00 720.00 . 16” x 8° 2035 Ibs 638.00 $17.00 WRITE FOR FREE CATALOG SOUTH BEND LATHE WORKS Madisen Street, South Bend, Indiana,U.S.A. Lathe Builders for 23 years—44,000 users § rr

Get Into Business This

Ball Bearing Throughout Weight 520 lbs.

Sent 7, Se FREE on , Ae. "al A whole year to pay. The Electric Carpenter Make money on screens, trellises, furniture, toys ete. 8-in. Circular Saw; 14-in. Band Saw; 36-in. Lathe, 10-in. Swing; 6-in. Jointer; Reversible Shaper; }-in. Hollow Chisel Mortiser; Sander. Does 35 Woodwork- ing operations. NOT a toy. Write Today for Illustrated Folder We also build a complete line of single-purpose machines The Woodworking Machinery Co., Inc. 258 N. Eleventh St. Phila., Pa.

Build and Fly this New Ideal CONDOR Plane! i latest idea in Featherweight Plans for Model Models; 22; in, size and weighs only Airplanes 25c each Floyd Bennett Monoplane FOKKER MONOPLANE New York-Paris Plane Curtiss Biplane DeHaviland Biplane NC-4 Naval Seaplane Bleriot or Nieuport Monoplanes Cecil Peoli Racer able wings; adequate power for long flights; interchangeable landing gear; easy, quick tonstruction. $ Get the CON DOR-Con- 1 struction Set. ......+++e0---- Ask your Dealer. or Order Direct. Postage 15 cents extra) Catalog f fs ky = Pittings, eaene for i Builders, 5 Ideal tee te & Sapply Co., Inc. 28 West 19th St. New York

FREE BOOK Shows How YOU Can a Fine Clocks Right at Home Of ClOCK —for yourself, or to sell at Big Profits Makin &, We furnish instructions, parts. Works Mi $1.65 up; others with chimes, all prices. Make case or assemble parts. Cash-in on demand for Mantel, Banjo, Grand- father’s Clocks. Write for Special Blue Print Offer, FREE Catalog. CLOCK ¢ COMPANY

details, prices of movements, Parts. Write Now for copy! AMERICAN C 1691-X Ruffner St.

Universal Jig Saw, Now’s the time. ess motor

ture, window novelties, etc. ready— Make Money in Somme Moments ] Season just open- This sturdy, rigid, ing. Make screens, garden furni- Universal Han boxes, Sell them and reap financial harvest. ments into extra money. Buy Boice-Crane and Build Better Marvelous how easily and quickly you make money. 1 Advise what to make. Explain how to make. Tell you how to sell it.

tourists’ saw, less motor, Turn idle mo- $30 Get

We help you.

Send 10c for complete 80-page A few evenings’ fascinating pas- Made High As $25.00 Day : : catalog showing and describing W. H. Duer, Mich. -o... time with clean, fragrant lumber a full line of Circular Saws, “Basement Boice-Crane Shop quickly pays for BOICE-CRANE Band Saws, Jig Saws, Jointers, Lathes and Accessories. Address Cur proposition.

earning high as $25 day.’’ Mingle pleasure with profit. ns equipment with the extra money you earn. BOICE-CRANE ma- chines are sturdy, staunch and Investigate

W. B. &J.E.BOICE, Dept. P.S.5-F, Toledo, Ohio true—capable of any reasonable wood-working task. mae

—____, thread of the screw through cup grease before starting it. An oil can filled with kerosene and one with gasoline will be found useful addi- tions to the bench. There is nothing bet- ter for hand stones, either natural or artificial, than kerosene. They cut faster with it and are more easily kept free from muck than with the heavier type of oil. Clean your hand stones with gasoline occasionally; you will find that they will cut much easier. Hard Arkansas finishing stones cut best when treated with water and a little soap instead of oil. If your stone is filled with oil, lay it in soft wood sawdust for a few days. After most of the surface oil has been absorbed go over the stone thoroughly with a mixture of pumice stone and water. Give it a good dressing with strokes at right angles to the direc- tion in which you use the stone. This removes any surface glaze and will make the stone cut better. Clean the stone with gasoline to remove all traces of | pumice. Rub a little soap on the surface

Fig. 2. Holding the chisel and stone in the hands eliminates the usual rocking tendency. of the stone and wet it slightly when you wish to use it. Bevel edged tools must never be ground on the back or straight side, as one secret of a perfect cutting edge is a true, flat back. When it is necessary to stroke the tool on the back to remove the burr, hold the tool flat on the stone. In removing nicks from the edge of a tool, grind from the heel of the bevel up to within a narrow margin of the cutting edge as shown at the top of Fig. 3. Do not grind off the edge, but work that into shape on a coarse hand stone. This method eliminates the danger of burning the thin edge in grinding. If a deep nick must be ground out, the edge left by the grinding wheel must all be worked off on the hand stone before you can finish it to a keen cutting edge. In honing chisels, plane cutters, and carving tools, hold the stone in one hand and the tool in the other (see Fig. 2). In this way the tendency to rock the tool is eliminated, and it is possible to get a much flatter and truer edge. Hold both the stone and the tool just firmly enough to insure easy motion (see Fig. 1). In delicately filing wood or metal, it is often an advantage to hold the work in your hands for similar reasons. Both work and file may be kept in any desired relation to each other with a high degree of precision. By draw-boring mortise and tenon joints (see Fig. 3), it is possible to insure an extra tight fit. Drill the hole for the May, 1930

© This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. os 45 es TH _ Mm FG AF,

a

Page 137

— OD -~ Set [TROOP eo ot on ie yf

May, 1930

— | dowel through the mortise, insert the | tenon, and, with an awl or pencil point, _ mark the center of the hole on the tenon. Next, withdraw the tenon and drill the dowel hole, making it slightly off center and toward the shoulder. If it is a soft wood that will draw up easily, you may shift the hole quite a bit, say a scant ' 14 in. or less. If hardwood is being used, 2; in. may be sufficient. Carefully insert a well-pointed dowel and driveit through. When planing down to a scratch gage mark, draw a soft pencil through the scratch. When the plane is down to the scratch the pencil mark will be visible from the top. You may make a series of sma‘l holes with an awl at intervals in the scratch mark, and when they show it | will serve as a warning to proceed with care. In ripping a thick board or a wide thin piece of lumber with a hand saw, turn the work over frequently so that the wood

SIDE EDGE OF CHISEL smait WHEEL PIN OR DOWEL GRINDS ~ SLIGHT HOLLOW EDGE SS SECTION OF MORTISE AND TENON SHOWING DRAW-BORING —

DOWEL HOLES! Fig. 3. Grinding a chisel, draw-boring a mortise and tenon joint, and driving nails into.an edge. is sawed from both sides. This will insure keeping to the line on both faces. Use a coarse tooth saw for soft wood | and a fine one for hard wood. In sawing thick lumber, rock the saw and change the angle of approach frequently. | When using a saw keep your eyes on a line with the blade and straight down the back edge. Do not grip the saw handle any harder than is necessary to control the blade. Take long strokes the full length of the saw, and follow through with a straight thrust to the end of the stroke. In making round wooden rods, first saw and plane them either square or flat, as the case may be. If you wish to make a round rod, spar, or flagpole, square it carefully to the diameter of the round wanted, work the square into an eight- sided figure, and then round off the eight corners of the octagon. If you wish to round off the edge of a table top, plane a bevel on the edge and then round off the corners of the bevel. Hollow-Square Saw Bench NE of the most valuable devices I have used in many years of practical Carpentry and shop work is a saw bench made in the form of a hollow square— just a rectangular frame supported by four legs. It is exactly like the framework of a low table with the top removed. _ Such a bench is particularly conven- ient for supporting material that is to be ripped or cut with a compass saw. It is equally useful for holding work which is to be nailed together or clamped for gluing. —F. G. SEMPLE.

.

POPULAR SCIENCE MONTHLY

135 Make Things Quickly and Easily with the NEW 1930

] -=— a Craftsmen, artisans, farmers, mechanics—all who use wood in their daily labors or spare- time hobbies—are delighted with the sturdy construction, splendid efficiency, and moderate cost of this Delta equipment. They appreciate keenly in the ‘“Handi-Shop” such exclusive constructional features as the Patented Tilt- ing Tables, Automatically-Oiled Bronze Bear- ings, Heavy U-Shaped Lathe Bed, Circular Saw ising Lever to mention but a few. Send coupon for complete description of this re- markable workshop. You <dll wndsentend then why men who know prefer “‘Delta.”’ New Woodworking Units The introduction of the Delta Jointer and Cir- cular Saw Units marks a new era in moderate- ly priced wood-working equipment. Now, for the first time, are available sturdy, practical machines in compact, convenient form at price levels astonishingly low. The individual units are built ruggedly to give years of heavy serv- ice. Both incorporate many special features of great value. The combination unit affords a compact, convenient arrangement which per- mits sawing and planing in one quick opera- tion. Either Jointer or Saw can be operated separately or both together. Welded steel stand of convenient height. All three units are furnished with ‘or without motor, as desired. 10 DAY TRIAL EASY TERMS For complete details and full description of the new 1930 Delta line, send coupon for FREE illustrated literature,

Delta Customers Delighted! “My combination Saw and Jointer arrived today and to say that I am pleased with same would be putting it mildly. Why, you've got everything I’ve ever seen beat a mile for qual- ity. price and quantity.”-—Lt. L. mith, Arizona. “Combination 8” Saw and Planer arrived. Have set it up and tried it out, finding it all you have claimed. I am more than pleased with quality and workmanship of this practical unit.’’—E. C. Chatfield, Conn.

Shows many items of interest to those who work with wood. You will learn, also, how you can try any Delta equipment for 10 days under actual working conditions at our risk. Choice of three convenient payment plans. Mail DELTA SPECIALTY COMPANY, Division of ‘“‘Delta Man 1661-67 Holton St., Milwaukee, Please send me FREE, illustrated literature describi it. B-530 ufacturi a coupon TODAY! Delta Specialty Co. Division of DELTA MANUFACTURING CO.

1930 model ‘Delta’? Woodworking Units. Also details o 10-Day Trial Offer and Easy Payment Plans, (Check spe- cial information desired. ) 0 Moulding Cutter Handi-Shop 4” Jointer Units r 8” Circular Saw Unit Combination 4” Jointer and 8” Circular Saw I am interested particularly for home use I am interested for shop and professional use

Address. 1661-67 Holton St. Dept. B-530 Milwaukee, Wis. A definite m for getting ahead financially wili be found on page four of this issue

tel, radio cabinet or it may be in any part of the home. Build a Ship Model at Home 7 It is a wonderful fascination and a BS beautiful decoration for your man- FREE CATALOG Just off the press. We have ts for the followi sy models: SANTA MARIA $4.98; L PINTA $4.98; MAYFLOWER -98; CONSTITUTION $6.98; LYING CLOUD $6.98. All F.O.B. Selleraville plus a few cents postage. These models are sold in knock down form. All are cut to . They will be sent hewee’ oe United States C. O. D. Money order or check Write for free illustrated catalog.

must accompany all foreign

MINIATURE SHIP MODELS, INC. . NA-S Sellersvitie,

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

Fully illustrated— Showi adi Boots, Clothing, Tents, etc.; for fish- ermen and motor cam pers. L. L. BEAN 44 Main St. ? Frecport, Maine

Page 138

SP ge eee a 136 « DEMANDS Where life may literally hang by a thread you will find “Little Giant” Screw Plates being used. Hence many a well-known aircraft manufacturer insists on their use. Life is dear—reputation equally so— in this great new industry, and its leaders cannot afford to takechances in their selection of materials and tools. When threads are to be cut or renewed, they must be sharp, clean, accurate, and experience has shown that they can be most easily insured through the use of “Little Giant” Screw Plates. In the plant, the railroad shop, the ga- rage, on the farm, and in the home— “Little Giant” Screw Plates continue to be the choice of men who know quality and who demand accuracy and dependability in threading tools. GREENFIELD § TAP AND DIE CORPORATION REENFIELO. MASSACHUSETTS POPULAR SCIENCE MONTHLY Kitchen End Table Holds Extra Pots HIS convenient kitchen end table is designed to hold the pots and pans | which are not for the moment being used | on the stove. A table of this sort need not be wide, but should be of about the | same height and depth as the stove. The | top should have a wear-resisting, heat- The top is protected by a wear-resisting, heat- proof finish or is covered with zinc or asbestos. proof finish, such as may be obtained by | Staining the wood and oiling it several times with linseed oil, well rubbed in. If preferred, the top may be covered with zinc or asbestos. A hidden receptacle for burnt matches made from a screw-top coffee can is an added feature of the table illustrated. To receive the matches, a 1-in. hole was | bored near one corner of the top and a 3- | in. length of brass tubing forced into it | until flush with the surface. A hole of i View of the underside of table top showing the top and body of the burnt match receptacle. the same diameter as the tubing was cut in the coffee can top, which was then fastened with screws on the underside of the table top as shown in the lower photo- graph. With a twist or two the container itself may be removed when necessary to empty out the accumulated burnt matches.— WALTER FE. BurTON. May, 1930 IL@ OY 45 e FIREE! With it a complete Home Instruction Book for beginners. It’s so easy you will play **America”’ in 30 minutes, and all popular airs in a short time. In a few weeks you can join band or orchestra or play solos and duets at home. Be popular. This offer is FREE. Send no money. It’s a beautiful new ‘1DlIoOn- factory guaranteed instrument. You keep saxophone and Easy Instruction Method 10 days. Return at our expense, or a and only $8 on eas ent plan. Same Femarkable FREE LOAN. offer on’ any Holton trumpet, trombone, clarinet or other band instru- No obligation to buy. Just ment. Send no money. No upon : sent Send This Co FRANK HOLTON COMPANY, 527 Church St., Eikhorn, Wisconsin Send on 10 days FREE loan a Holton Complete Easy Meth- a . 5 We Oa nae enna ee I Ci FREE INSTRUCT A YEAR’S PAY in 5 summer months Now there is a way to double your pay so sure that you cannot fail—so effective that a few months’ work brings in a year’s income—so on ee beginners like W. H. in right off the bat. Amazing’ Schoen (shown above) cash T SALES “Chain Selling’’ starts you—and REPEA take care of you the rest of your days. P Al NT! Direct From * Million Dollar Factory $24 a barrel commission on roofing—$16 average commis- sion on paint, varnish, enamel at wholesale prices and easy credit plan that swamps you with orders from home- owners, stores, factories, dairies, farmers, etc. DOUBLE PAY for your “‘Overtime’’—Write! No matter if you are now employed, you have “overtime’’ worth Pay with us. Write us now about the plan that leads to all- year-pay., five-months-work positions. We supply everything. State territory wanted, experience (if any), and time available. he Progress Paint Co. Dept. 149 Cleveland, Ohio © This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. New Fountain Pen-Pencil With compass. Guaranteed 2 years. Money back if not pleased. Sells for $1.25 Send only — for Wholsale Cata- log showirg over 400fast * Sellers, many idea! Xmasgifls. F.SPORS & CO. 330 Frank St., Le Sueur Center, Mina. Print YourOwn teenie: eng Advertising, 8, paper, circulars tags ¢ le Save money and time. Sold direct from factory only. Junior Press $6.90, Job Press, $11, Ro Do popular raised printing li en- graving —— any of our presses. » Sig Pays for itself in a short time. Easy rules sent. Send for catalog of presses, outfits, and all details. The Kelsey Co., B-33, Meriden, Cona.

Page 139

RITE REE ata- 00fast s gifts.

May, 1930

- How to Make Out a Money-Saving Lumber Order By CHARLES A. KING fora quiet evening when the purr of a car coming to a stop and the slamming of a door caused them to glance inquiringly at each other. “T guess that’s Fred,” said Alice, ‘and Dorothy is with him,” she added, as the sound of light and heavy footsteps mingled on the porch. “Good evening, folks,’ was Dorothy’s greeting as she and her husband entered. “Fred wanted to see John about his home workshop, and I wanted to see you—so here we are.” After chatting for a few minutes, John took Fred into his comfortable, well- arranged little shop, where there was always interesting work to be seen. “What I want your help about,” said Fred, “is making out a stock order; that is, a purchasing list of materials such as I need when I go to buy the lumber for making a piece of furniture or the like. For instance, I’m going to build a broom cabinet from this PopuLAR SCIENCE Monruty Blueprint number forty-nine. Now the blueprint gives a list of all the pieces of wood and their exact sizes— everything anyone needs to know for actually making the cabinet—but I want to find out just what to order and how to order from the lumber dealer.” Being director of woodworking in the city schools, John often had helped Fred in his hobby of making small articles, and he knew that this particular project was the most ambitious piece his friend had undertaken. “You must first recognize, Fred,” he began, “the differences in the objectives of a stock order, stock bill, or lumber order, and what is often called a cutting list, fitting list, or factory list. The list on the blueprint is a cutting or fitting list; it gives the number of pieces, their exact sizes as far as possible and their names, which indicates their uses and how they are to be cut or milled. Also, there are letters to tell where each piece is to go.” A LICE and John were cosily settled

o— seems pointed in the direction of what I am anxious to learn,” said Fred. “Beginning with the fitting list, what is the next step?” “You must become familiar with the blueprint in all its details, but you can use the cutting list to save measuring. Gen- erally a stock order is made from a broad conception of the whole, refined only enough to order boards of dimensions from which the different pieces may be cut with minimum waste and boards which conform to the sizes commonly carried in a well-stocked lumberyard. The one who makes out the stock order must know the standard thicknesses, widths, lengths, and grades of the various materials. “Lumber of practically every kind in common use comes from the mills in |

POPULAR SCIENCE MONTHLY 137 Drive Your Own Boat On Smooth, Uncrowded Waterways!

You can make real money ina new and uncrowded a Dee Wite uw fo on the Dee-W ite Profit- Building Franchise offer. No obligation. ! Dwight Lumber Co., Dept. 445, Boat Division, Detroit, Mich. ecko george Eleven Beautiful Models Await Your Selection Hull lengths 16 and 19 feet. Beam 4’ 6” and 5’ 10’. 4, 6, and 8 cylinder power plants. 20 to 40 miles per hour. 5 and 6 passengers. Prices— $535 to $2685, f. o. b. Detroit. Commercial Credit Plan deferred payments if desired. Dealers! eld with ranchise. ‘rite or wire today vr full information

4 I Gentlemen: 1 ) Please send me your 1930 free Catalog i ( ) Please send meintormationon your 1930 Dealer Franchise | ‘ i Name etcliei <i ! Address = n 1 Now you can own a real quality motorboat ata moderate price! Dee Wite offers for 1936 eleven tested models that give you speed, performance and luxury never before seen outside of very high priced craft. Sleek, all- mahogany hulls, with tough native white oak framing throughout, give you the high- est strength as well as striking mrss Equipment is complete throughout; includ- ing automobile-type controls, full-vision windshields, burgee and ensign, anchor and mooring equipment, choice of upholstery colors,and many otheritems. Twomodelsare sold withoutmotors,andninehavenationally famous power plants of up to 8 cylinders. aw modern plants, tremendous financial backing, and modern unit production make these outstanding motorboat values pos- sible. Dee Wite offers you the highest qual- ity and performance at extremely moderate prices,a featnever beforeattempted in build- ing high grade motorboats, The new free catalog, beautifully illustrated, gives full information on all Dee Wite models. ke orders insure delivery when wanted. coupon today for your copy—no obligation, DWIGHT LUMBER COMPANY Dept. 445, Boat Division Detroit, Michigen

Big Special Discount

Here's a modern 7-room home that you can build y ourself and save money = | We ship you the lumber cut-to-fit, freight paid to your station. Our simple plans and new system of cutting make it easy for anyone to build a Sterling home. No skilled labor necessary. Our customers claim average savings of 47%, over local builders’ prices. Rock-Bottom Prices! Mm Our large volume of sales enables us to quote rock- \ ttom prices and sell on time-payments without MA high interest or financing charges. Terms as low as $8.10 per month. Send 25c today for beautiful Color Book of NEW Sterling Home Plans and learn how you can buy a home with your rent money. International Mill & Timber Co. 3510 S. Wenona Ave. Bay City, Mich.

Hickory Tested! No Russell Jennings bit leaves the factory until, in the hands of a husky tester, it has bit its way into a hickory plank. That’s why they are what they are! Look for the full name on the round. The RUSSELL JENNINGS MFG. Co., Chester, Conn. wooall § BITS . ©

IT

Without Oil Filling Pipe Cap Cap does not contain screens, packing, filtering material or moving parts. Whirlo allows free escape of crank- case gases but no flying particles of oil can get by—they are collected and returned to the crankcase. It fits FORD “A” perfectly—just slip it on. mo to get out of order. Rigid, scientifically designed, money back if not satisfied. old befo Postage. © This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARDS. See page 8. of the motor. Oil rots hose draws grit and dirt into vital working parts—makes the motor blown out through the breather pipe. They c to form a dirty, greasy slime that is definitely harmful to genera- tor, starter motor and all parts of the your motor a chance—protect it—get rid of oll slime. The Whirlo og eer oll where alone. Send no money. 36-48 Flatbush Ave. —————————————————eeeeEEeeeeeee KEEP OIL WHERE BELONGS --IN THE CRANKCASE! the Whirlo Cap you are spraying oil all over the outside h connections—ruins ignition cable— re its time. Tiny particles of oil are constantly ollect on all surfaces

tion system. Give t belongs—in the crankcase. Costs aves in price many times over in rotted hose connections e mail it C.0.D. $1.00 plus few cents CARHART PRODUCTS Ext. B

Page 140

"POPULAR SCIENCE MONTHLY May, 1930 eee ae ae" - — EE ATS TS TATE ee RIN Nien ei ee NS Te ae ee ces ANTONY Frees cas FE SBM, wa oe eee ene Be ene ee ot Jim HENRY'’S GUARANTEE: 2 MORE good shaves per blade No matter what model of what razor you use, I guarantee you 2 more shaves (of course, I mean good ones) from every blade! Money back if I'm wrong. Check me up. Take a new razor, and count up the shaves. Better shaves? Why they'd have to be. When Men- nen gives you 2 more per blade, they must be better. _Remember, too, that Mennen alone gives you two kinds of shaving cream -.-Menthol-iced and W ithoutMenthol. Both give that clean, comfortable Mennen shave. Both build up a fine, quick lather in any water. Mennen Without Menthol issmoothand bland. Menthol-iced lather has a triple-cool tingle all its own. Both creams are typically Mennen ... that’s the main point...and my guarantee covers them both. Take your choice. And if you don’t want to buy a tube of Mennen, } ae in the cou- pon and I'll send jm PP : youa free trial tube. Mennen Salesman Mennen Talcum for Men removes face shine and doesn’t show... absorbs facial oils that come out during the day. Great after a bath, too. MENNen SHAVING CREAMS without MENTHOL “THE MENNEN CO. , Dept. P-2 NEWARK, N. J. Jim Henry: I’ve got a new blade all ready. Send me a free trial tube and I'll take the count. Name City. OSend me Mennen Mentbol-Iced OSend me Mennen without Menthol —— 9 ~-- thicknesses between one and three inches, and sometimes thicker. Usually boards thinner than one inch are resawed from planks, while packing box and other special lumber may be sawed directly to the required thickness.” “Generally the widths of boards range between six and twelve inches. Although boards up to fourteen inches wide and in some cases wider are cut from large trees, they are seldom more than fifteen inches wide and then are ordered only for special purposes. Wide boards are likely to warp and twist in seasoning, and if no thicker than one inch, they may split in handling. In lengths, boards range between eight and twenty feet, though probably three quarters of all stocked lumber is either twelve, fourteen, or sixteen feet long, and varies by multiples of two feet. 7OU will notice that in this drawing only over-all dimensions are given, the smaller pieces being dimensioned in the fitting list and identified by letters instead of being indicated on the plan. As the blueprint is for amateur use, this is the better way.” “Ves,”’ assented Fred, ‘I should think so because the many lines and figures necessary upon the print would be con- fusing to one not accustomed to working from plans.” “Now for the list,” said John. “We find that eight stiles or sidepieces are required for the case and the door, all two and a half inches wide and so nearly the same length that we may consider them the same. How wide a board would you order for these stiles?” “Well,” replied Fred thoughtfully, “eight pieces two and a half inches wide would require a board twenty inches wide.” “That is true,” agreed John, “but can you cut eight pieces of that width from twenty inches?” After pondering the question, Fred answered, “I didn’t allow for the width of the saw cuts nor for waste in working. How much should be allowed?” “For pieces nearly six feet long, about a half inch should be allowed. Each piece must first be cut roughly to length and width, one edge straightened on the jointer, and each piece finally cut to its exact width and length with fine fitting saws, and later rabbeted, grooved, or molded as required.” HEN the board would have to be twenty-four inches wide.” “Yes, if we ordered it that way. But do you think that after all these years of wasteful lumbering methods, boards of such width are so common that they are cut into narrow strips?” “IT don’t know,” “Aren’t they?” “They are very rare and command very high prices, and narrower boards may be purchased and worked more economically.” “T suppose we can cut a board twenty- four feet long and six inches wide in pieces six feet long, which will just give the eight stiles.” “We might, but are boards twenty-four feet long more common that boards twenty-four inches wide?” answered Fred. House Building and Painting Your House, John R. McMahon How to finance, =. build, remodel i keep up a house. Builder’s Architectural Taught, Fred T. Hodgson For carpenters, woodworkers and others who desire to learn drawing at home. 250 illus- trations. 18 plates. Price. . «és ge aw Bungalows and Riidiion Fred T. Hodgson and E. W. Braucher Perspective views and plans. Price... WOO. wee cere vece Drawing Self- - $1.00 A Practical Course in Roof Framing, R. M. VanGaasbeek A thorough explanation of underlying prin- — and their ap 7 to ae work. 116 illustrations. Price. oe ae Light and Heavy Timber Framing Made Easy, Fred T. Hodgson. Practical methods for all kinds of timber framing from the simplest to the most com- plicated. 420 illustrations. Price... .. $2.00 Modern Carpentry, Fred T. Hodgson A practical, complete treatment of ical 2 try, easily understood and non-techni volumes. 600 illustrations. Price... .. Practical Uses of the Steel Square, Fred T. Hodgson All that is possible to do with the square that is of practical value to the workman. 2 . volumes, 500 illustrations. Price... . .$3.00 Practical Bricklaying Self-Taught, Fred T. odgson A guide for the worting ‘taeagee. 300 } lustrations. Price. ..$1. Concrete, Cements, Mortars, Plasters and Stucco, Fred T. Hodgson A guide for the preparation and use of all kinds of plastic ne 8 material. Illustra- O86. TUG. .c.005. ... $1.5 Practical Heating Systems, Trouble Jobs and Ventilation, E. W. Riesbeck The fundamental principles and practical in- stallation of hot water, steam, vapor, vacuum and air line heating eneeune 82 illustrations and 61 tables. Price. . ee Practical Up-to-Date Plumbing, George B. Clow Covers the adaptation, installation, care and repair of all types of plumbing and hot water sea apa. 192 illustrations. an ‘ 1. rice . The Mixing of Colors and Paints, F. N. Vanderwalker Illustrated, — line a = color chart. Price.. . .$2.00 Modern Painters Cyclopedia, F. Maire A reference book for the ae and for the home decorator. Price. . ; . .$2.00 New Hardwood Finishing, Fred T. Hodgson Gives methods for working hardwood, with description of tools, and methods for finish- ing and ND all kinds of doses rice . Ee House Painting Methods, with the Brush and Spray Gun, F. N. Vanderwalker A dependable guide for contractors and journeymen. 141 illustrations and color chart. Price... ea dea arts onic Grazer The Ross Crane Book of House Furnish- ings and Decorations 6 color plates—1135 illustrations. Price . $3.00 Automobile Painting, Including Modern Lacquer Finishes, F. N. Vanderwalker This book covers the ute — in = detail. Price. apearngeies .. $1. Interior Wall Decoration, F. N. Vander- walker Plain and decorative Satine, — Lew working methods. Price. . .$4.00 Estimates, Costs and Profits in House Painting and Interior Decorating, F. N. Vanderwalker POPULAR SCIENCE MONTHLY 381 Fourth Ave. New York City

Page 141

May, 1930 POPULAR SCIENCE MONTHLY , Still the very best wrench you can buy Years of competi- tion and experi- mentation among wrench makers have not produced a better wrench than the famous all- steel TRIMO. Today it’s a better wrench than ever with its drop- forged steel han- dle, heat treated S so you'll never break it. TRIMO Pipe Wrench Made by TRIMONT MFG. CO. Roxbury (Boston), Mass. | there would be some waste,” “T suppose not, so perhaps it would be best to order one board twelve inches wide and twelve feet long.” “Exactly. Now about the shorter pieces; we will begin with the largest first. The top is twenty-four and the bottom nearly twenty-one inches long, so both pieces may be cut from a board four feet long, as it is not customary to cut fractions of feet. The top is seventeen inches wide, and the bottom fifteen and three eighths wide. How wide should the board be?” “If it were seventeen inches wide, it would be wide enough for both pieces, but answered Fred. “Usually. If we were ordering for a large job, we would specify the desired number of square feet of random widths and the required length or vice versa according to our needs, because in general pieces over ten or twelve inches wide are glued from narrow boards.” HY is that?” queried Fred. “TI should think that one wide board would be much better than another made of narrow pieces.” “It may seem so, but as a matter of fact the opposite is true, for one wide board is more likely to warp than a board made of several pieces, each of which warps separately. A skilled workman arranges the pieces so the warp of one is offset by the opposite warping of others; hence we will order one board ten inches wide and eight feet long.” “Wouldn’t that make a board twenty inches wide and therefore waste three inches? Why not say nine inches wide, | which would waste only one inch? “If we happened to get a perfect board, that might be safe for an expert workman, but we must allow for edge blemishes and for making the joint. Also, boards are stacked out of doprs for several months for weather drying and furniture and | finishing stock is then kiln dried, in which | process practically every trace of mois- | ture is removed by evaporation. What will be the result?” “T suppose the board will shrink and warp more or less.” URELY, but just now we are more interested in shrinking. A green board sawed twelve inches wide will shrink from one quarter to one half inch in width, depending upon whether it is plain or "quarter- sawed and the kind of wood, for plain-sawed lumber shrinks more. When your ten-inch board reaches you, it will be about nine and five eighths inches wide. Work off bad edges, make the joint, and the board will not be a great deal too wide; in any case a nine- inch board would probably not be wide enough to allow for squaring. Now for the short pieces: there are eighteen two and a half inches wide—we will say three inches. Twelve of them will average a foot in length, so a board six inches wide and six feet long will give them. Six other rails average about twenty inches long and will require five feet in length. Thus the rails will need eleven feet in length. How shall we make the order?” “T should say eleven feet long,” Fred answered without hesitation. © This seal on an advertisement in POPULAR SCIENCE MONTHLY signifies the approval of the INSTITUTE OF STANDARVS. See page 8. 139 » » SHAVE ELECTRICALLY That Clean-Cut Look “Happy Wa E Walle of Life use the” VIBRO-SHAVE Electric Safety Razor In this day of ACTION, minutes count and appearances matter. Now electricity comes to aid men—definitely solving the shav- ing problem. Just plug the Vibro-Shave Electric Safety Razor into any light socket and merely guide it over your face. You will experience one of the greatest miracles of this modern age—a clean, close shave without scraping! The rapid movement of the blade, one-onehundredth of an inch under the safety head of the razor, shaves the hair at the base— insuring a clean shave without nicks, raw red spots or ingrown hairs. You owe it to yourself to enjoy thisnew shaving ease and positive safety. The VIBRO-SHAVE massages as it shaves, waking up tired facial muscles and nerves, revitalizing skin tissues. You look fit and you feel fit. If your dealer cannot supply you let us send direct. Our guarantee goes with each razor. Just use the coupon below. Mail it today! ELECTRIC RAZOR SALES CORPORATION OF AMERICA 160 N. La Salle Street, Chicago, lil. Eastern Office Graybar Bidg., New —" City Canadian Electric Razor Sales of Canada Tramways Bidg., Montreal Jobber and Dealer Inquiries Solicited $ 5 COMPLETE ($6.50 in Canada) Si Bent Bi, Chcage, for which you will mail me lenclose sosteala @ Vibro-Shave Electric Safety Razor ith blades, cord and id t _ M0Valte AC. plug and your guarantee. ASK YOUR DEALER OR CLIP THE COUPON

Page 142

alae ind nal RRL, Min i. 201 T CS ain e a taeni Sk oe a cia SUP RS. MESS ee ee

= PORTABLE HAND OPERATED UTTING TOOLS. Along the sides of this advertisement we show the cut- ting jaws of several Porter Tools and below, close up views of these tools in use—Shear Cutter on wire rope, Angular Cut- ter on tie wire, Nut Splitter ready to remove nut, End and Angular Bolt Clippers and the Chain Cutter. These represent pular models in a line of 60 power- ful portable hand operated cutting tools—all of them built on the lever andtoggle joint principle which multiplies applied power about 70 times. The largest Bolt C xr cuts an- nealed bolts inthe waa. % inch. 5-8 inch soft wire rope or L 1-2 x 9-32 inch soft bars. Porter tools are quick -they save time and la- bor in production, dis- mantling, maintenance and repairs. They are used in practically every industry. Write for descriptive lit- erature; ask your jobber. H. K. PORTER, Inc. 7 Ashland Street EVERETT, MASS. ©

POPULAR SCIENCE MONTHLY

May, 1930

a twelve-foot board,”’ objected John. “Then we will order the board six inches wide and twelve feet long, for we will have to pay for it anyway.” “Just so,” said John. “Let’s take the shelves next. The top shelf is three quarters by eight by twenty-two and a quarter. As three-quarter-inch boards are rarely carried in stock, the thickness usually being seven eighths or thirteen sixteenths, we will change the length of the ten-inch board from eight to ten feet, which will allow for the top shelf. The | piece may be planed by hand to three quarters inch thick. Next, a board five eighths by eight inches will be needed for the shelves, shelf end, and the drop door. | It will have to be seven feet two inches in length. What shall we order?” “THE board should be five eighths inch thick, nine inches wide, and eight feet long,” answered Fred. “Correct. Now you seem to catch the idea. And remember always to cut the large pieces first from the boards which will cut with the least waste. Now let’s see if we have everything.” They scanned the print and added some stock for racks, cleats, and shelf rests. “But how do we order the plywood panels?” asked Fred. “Well, that stuff is like glass in that an order for a special size is cut from the next larger size in stock, for which the buyer must pay. We want one piece eighteen by sixty-one inches, two pieces twelve by sixty-one, and one piece twenty-two and a quarter by sixty-one. In general, three- ply wood is stocked in sizes of twenty- four, thirty, and thirty-six inches in width, and sixty, seventy-two, and eighty- four inches in length. We have one panel eighteen inches wide which must be cut from a twenty-four-inch board, an un- | avoidable waste. Then we want two panels twelve inches wide which may be cut from another twenty-four-inch board, while the twenty-two and a quarter inch panel will take another. Thus we need three boards twenty-four inches wide. The print calls for sixty-one inches in | length, which is one inch more than the stock length of the panels.” Mt pore means that the panel must be cut from the next length. How may that waste be avoided?” asked Fred. “A slight change in the design will | prevent this waste; the bottom rails of all the sides and door may be made one inch wider, which will allow the panel to be made sixty inches long. The difference in the design will not be important.” “That would make a difference in the | stock bill,’ commented Fred. “Ves,” agreed John. ‘What shall we do about it?” “The rails were to be cut from the seven eighths by six inch board twelve feet long, if I remember correctly; why not add two inches to its width?” “That’s the way to do it, so we will make that board eight inches wide instead of six. If you make this adaptation, you will use three pieces of three-ply board twenty-four inches wide and sixty inches long, or seventy-two inches long if you decide to let the present design stand.” “But the dealer will have to cut it from |

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

TWENTIETH CENTURY BOOK OF Recipes, Formulas and Processes This book of 800 pages is the most com- plete Book of Recipes ever published, givin thousands of recipes for the manufacture o valuable articles for everyday use. Hints, Helps, Practical Ideas and Secret Processes covering every branch of the useful arts are given. 10,000 Practical Formulas—The Best Way to Make Everything A book to which you may turn with confidence that you will find what you are looking for. A mine of information, up-to-date in every respect. Con- tains an immense number of formulas that every one ought to have, that are not found in any other work, Price, $4.00 Popular Science Monthly 381 Fourth Avenue, New York

Heaven and Hell The most interesting of the Profound Writings of Emanuel Swedenborg The renowned theologian, phi- losopher and scientist. 632 page book treating of the Life after Death, sent without further cost or obli- by ¢ gation on receipt of Write for complete list of publications SWEDENBORG FOUNDATION, Inc. Room 1261 18 East 41st St., New York

WANTED 100 MEN TRADES THAT PAY O

CUT OUT THIS AD. Check course interested in and mail to me for Free Book and all details of my fully equipt three buildings, 38 instructors, Free employment service. Special Railroad fare allow- ance and other services that will help fit you for a goox opportunity. MAIL COU- PON TO-DAY! L. Ave., GREER COLLEGE 72 5,020*ii 4"*’ Name.

Machine Shop ........... Automatic Screw machine .. O Elec-Refrigeration........ O

Address.

City. State. —_

ADDS TO ANY INCOME Costs Next to Nothing. No Personal Selling R quired. Make immediate, immense and endless prof- its. Become a Vacuum Cleaner Builder and Service Expert. New evergrowing field. Readily mastered under our expert advice and full instructions which are entirely free. Valuable secrets revealed for firet time. We can supply all needs. Using spare-time. start a home, branch factory all your own. End Un- certainty forever. Be your own s. Pay your own salary. Undersell all. Lead all. Literature tells how and why. Join us, the originators. URON ASSOCIATED INDUSTRIES 1306 Engineers Bldg., CLEVELAND, OHIO, U. S. A.

A definite program for getting ahead financially <-‘ll be found on page four of this issue.

Page 143

ea7Sasasey S42! Le

May, 1930

“By the way,” said Fred, “You remember the last time you took dinner with us, we talked about a dado around the dining room; why not make it of this | three-ply stuff?” “You can, for the panels come with | either one or both sides finished in almost any kind of wood. They are made in various numbers of plies; and with se- lected facings, you can obtain beautiful grain effects.” “ OW,” said Fred, ‘I guess the list is 4‘ done, for the plywood was the last | item, I believe.” “Not too fast. We have said nothing | about the kind or grade of lumber. Stand-

ard gradings are changed from time to | time, but for small orders it is of minor importance. We must however make some statement.” John tore a sheet from his notebook and wrote the following order: MATERIAL FOR Broom CLOSET ALL material to be of clear, sap-free white- wood, one side free from bad discolorations and other hurtful blemishes. 1 board “@ t<ti2° HO DZS 1 board 4°: xsi7?C’ DIS 1 board @ xs 2’ sire’ Das 1 board oe”: O sO’ Dis 3 three-ply boards 24 x 60” (72?) “From now on,” said Fred, “I think I shall be able to make an intelligible stock order. Is there any conventional way of writing down the items?” “No. If the list is clear to the dealer and the stock cutter, that is all that is necessary. Terms vary in different localities and in different shops. Some-

times the thickness of the board is placed | first and sometimes the length. Usually the small dimension comes first, but this is not universal.” “What does ‘D 2 S’ mean?” “Dressed two sides. If that were not specified, the dealer would be justified in sending the boards in the rough, although | it is hardly likely that he would do so, since he knows what the lumber is for.” “‘What sort of boards would be dressed differently?” ““NOVERING boards, underfloors, and box boards are often dressed only on one side, not for smoothness but to make them of uniform thickness in the interest of greater economy in working | them. Corner boards, standing finish, and square-edged floor boards are dressed four sides to insure uniformity. Often in unplastered camps and summer cottages, the studding and all boards are planed on the sides which show in the rooms. This planing reduces the thickness of one-inch boards to the standard thickness of seven eighths.” John pointed out that sometimes the delivery of a small order may be simplified by a notation that certain boards may | be cut across at a given distance from one or both ends. “In this case, fourteen feet is a rather _ awkward length for so small an order,”’ | he said, “but this may be remedied by | cutting the stiles from one end. The other boards may be cut the same way with a little planning.” “T will take this list to Sheldon in the morning. I wish, however, that I could

POPULAR SCIENCE MONTHLY SUCCESS IN RADIO 141

Depends Upon Training ».- You Get that Training with RCA Institutes, Inc. REGARDLESS of who you are... how old you are. . .where you live or what you do... You, too, can make a success in radio because RCA Insti- tutes trains you for success. This is the only school backed by the Radio Corporation of America... the foremost radio organ- ization in the world today! “A Serious Shortage of Trained Men Exists Right Now” Thousands of men are needed. Broadcasting stations, manufacturing plants, retail and whole- sale dealers, as well as ships at sea and planes in the air are now waiting for men like you . . . men who have the will as well as the knowl- edge to make good. They know that the graduate of RCA Institutes has the knowledge and ability to hold a good position in radio. Inside Information dbout Radio .- + Quickly and Easily Yours See how easy it is to learn at home in your spare time ... Mr. Lawrence A. Aicholtz says: ‘‘Your course is without a doubt the very best of its kind and the training I received has enabled me to work up to the position of Chief Remote Operator of WSAI.”’ We have received hundreds of letters similar to this . . . Each letter a ‘‘true story’’ of success in radio. You get your lessons and criticisms direct from RCA . .. the very source of radio achieve- ment . . . the organization that made Radio what it is today .. . that spon- sors every lesson in this course. Remarkable Outlay of Apparatus Included with this Famous Laboratory Training Course You learn radio by actual experience with the famous RCA Institutes outlay RCA INSTITUTES, INC. Formerly Radio Institute of America

Radio I $2000 to $4500 of apparatus... A complete assortment of parts assembled for your help and in- struction by RCA experts. See for your- self how easy it is to solve every radio sheep such as repairing and servicing ° ne sets. Here is the training that you cannot duplicate elsewhere, at any price. Students learn by actual ex rience, under the direction of nationally known instructors. RCA Graduates Find It Easy to Fill Good Radio Jobs For more than 20 years, there has been a radio job for practically every graduate who wished one. RCA Institutes stu- dents are actually trained for success in Radio... That is the Big ages of this organization and that is why students make such rapid progress in Radio. Every student receives an agree- ment signed by the president of this school assuring absolute satisfaction upon completion of the course... or money refunded. Clip this Coupon NOW!

P.S.M.-5 RCA INSTITUTES, Inc. 75 Varick Street, New York, N. Y. Gentlemen: Please send me your FREE 40-page book which illustrates the brilliant opportuni- ties in Radio and describes your laboratury- method of instruction at home!

Page 144

POPULAR SCIENCE MONTHLY May, 1930

Lomas aaa eae a eS db ad cos eke Ae,

He flew the first air mail from the United States to a foreign country With more than 5,000 flying hours to his credit, he has taught Aviation to many men now holding big positions as pilots and executives. rE wey d a’ ef ‘ & ND now together with a , hd £ t <-% group of noted flyers and Lieutenant Commander Iseman »)

“oF ‘ae

technical experts, he has put into a great new operating Manual a complete course | for beginners in flying. It is so accurate, so thorough, so reliable, and yet so simply and graphically explained that not only do beginners advance themselves with far | greater rapidity through its use, but engineers, pilots, executives, and other leaders | in aviation are using it and proclaiming it the best general reference guide-book in the whole field of Aviation. ' The Aviation Manual | Edited by

P ) s,150 Lieut. Commander John W. Iseman, U.S.N.R. pom weabh ons ea HW Commander Iseman has more than 5,000 flying hours to a pare | his credit. Additional contributors are Col. N. J. Boots, preteens, «A Siew General Supt., Roosevelt Field; Merwin M. Peake, Cur- tiss Flying Service; G. B. Speir, Curtiss engineer; J. D. Peace, Jr., Specialist in Instruments; Otto H. Lunde, Fairchild engineer; Lieut. Assen Jordanoff, veteran pilot; Travis Hoke, authority on meteorology. ; A Complete Ground Course for Be- ginners in a Single Handy Volume “How can I get into aviation?” many men are asking. “And what must I know before I can take flying lessons?”” This great new book is the answer to both questions. In a clear, thorough, and practical way it completely explains all of the things the be- ginner must become familiar with—it offers the niremns needed by the man who wants to fly—it presents the knowl- edge he must have of planes, motors, and instruments; of the theory and practice of flight; of license regulations, air traffic rules, and the requirements of commercial] aviation. y) sence Graded Chapters on Airplane ible Bound in Handbook style — gold edges.

Construction, Equipment, and Control Power Plants The Manufacture of Engines Instruments Opportunities in Aviation The Business of Flying License Requirements fications for Flying Elementary Airplane Design raining to Be an Aviator Materials and Their Properties Your Background of Reewledge Wings and ‘‘Props” Aviation Schools and Flying Clubs Wind and Weather How to Get the Most Out of a Fly- How a Pilot Inspects His Plane ing Course Learning to Fly Your First Outfit . gZ Standard Airplanes, Seaplanes, and Laying an Air Course Amphibians Air Traffic The Construction of Planes The Laws of Aviation FREE EXAMINATION

FREE Examination Form Popular Science Publishing Co., P.S. 5-30 381 Fourth Ave., New York Please send me a copy of The Aviation Manual. Within 10 days of receipt I will either return the book or remit $5.00. We offer to send the book to you for ten days’ examination. Within that period you 1 may return it and owe nothing. Our un- 1 usual manufacturing facilities together with the large edition it is possible to make of a book in such great demand, enable us to place the low ee of $5.00 on this book. NO MONEY IS REQUIRED until you have examined the book itself. Send the coupon.

PN 64 ci esdbaekceukscxGtupeiciveinaessvcadesnntcantwe Popular Science Publishing ua Co., IL cnc cisiken cnpadecetaenadetiaies ninsccesndeanel 381 Fourth Ave., New York ESTER ATE LOTT POE IT.

have the boards cut up somewhere near the sizes I want.” “Well, you can have the lumber | delivered at a job shop—Davis’, for | example. He will work every piece to just the sizes and shape the fitting list calls for. Probably he would get out the entire order for you, because he carries a good stock. But he would have to charge you more than Sheldon would. In fact, his price would probably stagger you. We have spent some little time studying the print, and he would have to pay a high- | priced workman to do the same thing, and | also for his time in laying out the pieces so | they may be cut with minimum waste. | Machine work, requires time. It takes as much time to knock down and set a _ machine for a small order as for one many times larger; all this would appear in your _ bill, plus the overhead charges.” “FINHEN what am I to do?” asked Fred. “Sheldon can’t cut up the stock, and Davis’ price would be almost prohibi- tive.” ‘There are three methods. The first we may call the factory method, which I have just described. The second we shall call the yard method: you go to the lumberyard with the purpose of each | board on the order clearly defined, keep- ing within the range of straight crosscuts with the power swing saw and lengthwise cuts with the power rip saw. For example, the eight inch by twelve foot |- board from which the rails are to be made may be cut across six feet from one end and that piece sawed down the middle with a circular rip saw for the bottom rails; the other piece may then be ripped for the other rails. Sheldon has machines for this sort of work, but not for the finer cutting. The other boards may be cut by the same method. This will not be as expensive as the factory method. “The third method may be called the personal method, which I should follow if I were working as you are. All the stock your order calls for should be delivered at your house. Lay the pieces out care- fully with allowances for working, see that your saws are sharp, and go to it. It will be fine exercise for you after a hard day at your desk. Furthermore, the waste wood which will be useful for other jobs, will be in your hands instead of in the scrap pile in the shop.” | “ JOHN, you are absolutely right! I have already found that a couple of hours playing at my bench in the evening has rested me far more than reading or any social affair. I will order the boards and cut them by the personal method.” Dorothy’s voice from the doorway broke into their conversation. “Talk about women stalking!” she exclaimed. “It is nearly midnight and you boys have been talking a steady streak since half past seven. You come right along home, Fred.” “Well,” said Fred as he sprang to his feet, “I just didn’t realize—I have been so interested in what John has told me that I have thought of nothing else. It’s certainly been a worth while visit. I’ve learned all I want to know about ordering lumber.”

Page 145

weomli ts Wm ee ie wer 7 oe a. a o May, 1930 New Ideas Sweep Movie Studios (Continued from page 23) step was the installation of a large, complete sound stage, where conditions prevailing in actual production practice may be duplicated It is fully equipped with microphones, camera motors, and all other apparatus necessary for the taking and finishing of talkies. Of the studio innovations, the most impor- tant is the Schufftan process, the invention of Eugen Schufftan, a German artist, through which German and English producers have been enabled to make “million-dollar” pic- tures at trifling cost. Recently, the first Schufftan unit of two experts arrived in south- ern California. As a result of their work there, you soon may see “super-features” with im- pressive sets and foreign backgrounds, such as great cathedrals, medieval castles, majestic mountain scenes, which have been produced inside a Hollywood studio at an outlay of a few dollars. EMONSTRATED at a meeting of the Kinematographic Group of the Royal Photographic Society in London recently, the process amazed experts by its ingenuity and simplicity. Described briefly, it is a method of combining real sets with small models, or combining photographs with small inexpensive sets in such a way as to blend the two into a whole and make detection by the spectator impossible. So perfect is the illusion that, when the finished picture is thrown on the screen, Schufftan technicians themselves can- not tell where the set leaves off and the model or photograph begins. Yet all that is required is an optical mirror and a large lens—plus a knowledge of angles and a highly developed technique of film lighting. With such simple equipment, Schufftan has been able to show on the screen foreign scenes, including the Colosseum in Rome and the Vienna Opera House, without leaving the Ufa studios in Berlin, using photographs instead of costly sets imitating these huge historic build- ings. In Aélantis, a German film based on the Titanic disaster, Schufftan’s process was used in many of the interior scenes. The director wished to make various shots showing the passengers being engulfed with the sinking ship. By the old method it would have been necessary to flood the studio or lot and build an expensive set merely to destroy it. A model of the top of the liner’s ballroom was built. The actors floundering in a small tank pro- | vided the remainder of the scene. The result is as realistic as would be a picture made at great expense and effort. ETROPOLIS, the German film which a few years ago attracted international at- tention chiefly because of its futuristic sets that appeared in gigantic proportions on the screen, employed tiny models and the Schuff- tan method. The models were built for a few hundred dollars. Actual sets on the scale sug- gested would have cost a considerably large fortune. A most realistic battle scene was produced with a cheap model. The actual studio con- struction involved was one shell crater in which the actors played the sequence. Across the small model of the battlefield, a miniature airplane moved in flight. As the toy plane crossed a designated spot, a tiny calcium bomb exploded and brought it down. The effect was startlingly lifelike, though it cost less than $100 to produce. Another Schufftan set, supposedly made in a great astronomical observatory, employed an ordinary table microscope to give the illusion of an enormous telescope. ; According to Hans Nieter, a young German- American camera man who worked in the Ufa Studios with the Schufftan process since its beginning, seventy per- (Continued on page 144) POPULAR SCIENCE MONTHLY Herschel Logan with drawings made (1) before and (2) after Federal School turns INK toGOLD Heascret LOGAN wanted to make money. He liked to draw, but his work (an example of which is shown in No. 1, the small crudely drawn heads above) was not good enough to sell. Seeing an advertisement of the Federal Schools, he filled out a coupon like the one at the bottom of this page. Now compare his recent work, No. 2, with the crude ink scratchings he did before he enrolled in the Federal Course. The drawing of Lincoln shows that Logan understands the proper application of ink. You can see for yourself how the Federal Course has “steadied his hand. This is the type of drawing that is simple, strong, masterful and pays big money to the man who can do it. Mr. Logan is just one of the hundreds of young people making good money because of Federal Training. Publishers buy millions of dollars worth of illustrations like Logan's every year. If you like to draw let your talent make your fortune. Fifty famous artists contribute exclusive lessons and drawings especially prepared for the Federal Course. It's easy to learn the “Federal Way. Study at home in your spare time. Test Your Drawing Talent Many people have a talent for art and do not realize it. It is well proven by Logan's first work compared with his drawing of Lincoln. Do you like to draw? A liking for drawing usually indicates talent which can be developed. Our Standard Vocational Art Test will tell you just how much ability you have. Send for it, it’s free. We will enclose with it our illustrated booklet, “A Road to Bigger Things,” which explains illustrating as a profession, tells about famous artists who have helped build up the Federal Course and shows the remarkable work of students. You'll want both the booklet and the test chart. Fill out the coupon now. FEDERAL SCHOOL of ILLUSTRATING SI40FEDERAL SCHOOLS BUILDING MINNEAPOLIS, MINNESOTA Federal School of Illustrating 5140 Federal Schools Bldg., Minneapolis, Minn. Please send your free book, ““A Road to Bigger Things,” together with your Standard Vocational Art Test. Name Age——— Occupation— Address

Page 146

i 7 att i tats sop tori STN CITT Col. Edw. V. Rickenbacker and a 30-passenyer }okker This Spring get into AVIATION Eppre RICKENBACKER had the right idea! Twenty- five years ago he was just a boy working in a garage. He took the International Correspondence Schools Automobile Course—studied in spare time and learned the fundamentals of gasoline engines. That was the groundwork of his famous career—first as an auto- motive engineer and race driver—then as America’s foremost ace in France—now as Vice-president of the great Fokker Aircraft Corporation. Aviation holds the greatest future of any career a@ young man can choose today. Get into it now, by the shortest, most practical route—from the ground, as a mechanic. Study engines! The new I. C. S. Course in Aviation Engines offers you a marvelous opportunity. You don’t have to have experience or a large amount of capital. You don’t have to give up your present job. Find out today, without cost or obligation, just how this course will prepare you for a career. Mail the coupon now/ INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7660-F, Scranton, Penna. “The Universal University’ Without cost or obligation on my part, tell me how I can qualify for the position or in the subject before which I have marked an X: DO AVIATION ENGINES O) Complete Automobile i. Gas Engine Operating ‘course — Gas Engine O Automobile Electric Course Equipment Architect Electrical Engineering Electric Lighting Mechanical Engineer Mechanical Draftsman Machine Shop Practice Architects’ Blueprints Contractor and Builder Architectural Draftsman Concrete Builder Structural Engineer Railroad Positions Pharmacy Civil Engineer [1] Mining Chemistry Surveying and Mapping Agriculture Plumbing and Heating Navigation Steam Engineering Mathematics [) Radio BUSINESS TRAINING COURSES Business Management Advertising Industrial Management Business Correspondence Personnel Management Show Card and Sign Traffic Management Lettering Accounting and C. P. A. Stenography and Typing Coaching English Civil Service Cost Accounting Railway Mail Clerk Bookkeeping Common School Subjects Secretarial Work High School Subjects Saiesmanship Illustrating Spanish [() French Cartooning isis ieiitosi dial dsiglidivsasadedliptionsecbeeikheabsile eaiblindanitinennisdiieadiaaniaiaanaiaii SET ARTI cococnnnapscanpgnpenneetnscentanapinidenseuaspenemeneenenntnineenat i liaitnnencibindiaidupniten dceiaemiiieasipeaats sess actcateusatingencasinenmaiinn III hts cacnntedaidentsislisielip nouns tcdduassaseanhenheentstnimeesnnanial If you reside in Canada, send this coupon to the Inter- national Correspondence Schools Canadian, Ltd., Montreal Be A RaiLway TRAFFIC. INSPECTOR Active men—19 to 55—needed in this profitable permanent profes- sion. Travel or remain near home— with expenses paid. Excellent opportunities—promotion rapid. Meet high railway officials. We assist you to a position paying $120 to $150 per month plus ex- penses upon completion of few Y weeks’ spare time home instruc- tion or refund your tuition. Ad- vance with experience to $175, $200, $250 per month plus expen- ses. Our free booklet shows how to,make your future ‘a certainty. Write for it today. Standard 3 Susinece Train. Inst. Hin, %y Sumate, | the green. POPULAR SCIENCE MONTHLY New Ideas Sweep Movie Studios (Continued from page 143) cent of all German productions now use the method. To date, twenty-three British pic- tures have been made with its assistance. Soon ' after his invention was introduced in the Ger- man studios, Schufftan was invited to Holly- wood to demonstrate it. He remained several months but no one seemed to take his work seriously and experiments were abandoned. That was five years ago. Meanwhile, however, sound has come into its own. Now, with the small studios necessary for talkie production and the great difficulty of reproducing sound in outdoor scenes, synthetic sets have become a vital problem. Thus it is expected that the Schufftan unit which arrived in the movie colony the other day will prove the nucleus from which will grow the general adoption of the system in this country. These, then, are the three major new de- velopments in movie making technique— color, wide film, and the Schufftan process. What are their secrets? To begin with techni- color: It is the invention of Dr. Herbert T. Kalmus, a former professor of the Massachu- setts Institute of Technology, who, with a group of scientists, worked more than a decade to bring it to its present state of development. This is how an expert explained the process to } me: i tv scene you will eventually see spread on the screen in glowing tints is taken with a special camera. It is equipped with a prism arrangement which, because it splits the scene into two duplicate parts, can take two identical pictures at the same time on succeeding sec- tions of film. In consequence, twice the footage is used for a given scene. Through color filters placed in front of the upper and lower frames of the film, which is color sensitive (panchro- matic), one section registers only the reddish or “warm” colors, and the other the greenish r “cold” colors. The film, when developed, resembles a nor- mal black and white negative, except that each alternate exposure includes only the red or Two separate positive films are printed which are to serve as “blocks” in the printing of the final film. One of these two positives forms a continuous strip of only the red frames of the negative; the other of only the green. The two positive films are chemically treated so that the dark portions of the image are caused to swell out from the surface of the filn. The uneven surfaces thus created later act in the printing process like the raised let- ters on a rubber stamp. A dye of suitable red lish shade is applied to the positive of the red parts of the picture prepared in this way, and by mechanical contact the red portions of the scene are transferred to a blank film. The green parts of the scene are printed from the | other positive film directly over the red im- pression. The resulting film in full color can be run through any projection machine in the ordinary manner. S FOR Grandeur and Spoor-Bergren films, the pictures are taken and projected with more highly corrected lenses capable of giving sharp detail to the edges of a wider field. The chief technical difficulty lies in running the seventy or sixty-five millimeter film through the camera and later through the projector and keeping it from buckling and causing areas of the picture to appear out of focus. This, technicians say, has been overcome by a special mechanism which practically “floats” the film through camera and projector on a “cushion of air.” Details of the method, how- ever, are still being kept strictly secret. To obviate the buckling obstacle, Leon F. Douglass, a California experimenter, has devised a panoramic lens (Continued on page 145) May, 1930 High Schoo} Course in we Ley a pro’ A m ts for entrance to a es 20 ) Other =" Courses = whieh 708 need ce success, Nomatter what ou oes AMERICAN SCHOOL, Dept. H-548 Drexel Avenue and 58th St., Chicago Send me full Information on the subject cheoked and | how you will help me win success in that line, rchitect --.-Electrical En ineet ----Building Contractor “General Educat : ucation ----Automobile Engineer ----Civil Engineer Mach. mead Practice .---Structural Engineer ----Mechanicat Le oond -pusnne Mana & ...Steam -...C. P. A. & Audi a Je. Designer ---- Bookkeeper :... High School Graduate Name. c Age. asso ccieeteepedaatnsbaials I cisinishicheiiiid talihiiiecinticid ielisiideadlei State. COLLEGE COURSES AT HOME Carry on your education. Develop power to ini- tiate and love. Earncredit comand a Bachelor degree or hea ny Certificate by ence. Select rom 450 courses in 45 subjects, ~~ cluding Engl ish Mathematics, History, Edu- cation, Psyc ies, the Languages, etc. Write for ake. The Gnibversity of Chicago 451 ELLIS HALL CHICAGO, ILL. HowTo SecureA Government Position Why worry worry about strikes. layoffs, hard times? Get a Government job! Increased salaries, steady work, travel, good pay. I'll help you become a Custom House Clerk, Raltway Postal Clerk, Post Otfice Clerk, City Mail Carrier. Rural Carrier—or get_into any other Government job you want. I was a Secretary Examiner of Civil Service Com- mission for 8 years. Have helped thou sands. Railway Postal Clerk examination coming, My 32-page book tells about Now she jobs eg nd the can Dp you get one. nd the coupon! Free for your copy TODAY. = —_ A. R. Sutheunatn Civil Service Expert, , PATTERSON SCHOOL, 165 Wisner Bidg., Rochester, N. Y. Please send me, without obligation, your free book ‘How to Secure a Government Position. Name New Kind Of Can Works Like Magic! At last! An automatic, simple little can opening machine for the home. This revolutionary invention in only a few short months has banished old AGENTS Men and Women have made up to 36 and $8 in an hour, full or pare time. Big, worthwhile com- missions on every sale. Exclusive Territories. Send quick for FREE TEST Offer. —_ openers from over 100,000 ki ens. And no wonder! Imagine an amazing, lifetime device that holds the can and cuts out the top leaving can rim slick, smooth and clean. Just turn a crank, that’s all. Approved by Housekeeping Inst., Modern Priscilla, etc. Write today for special introductory advertising offer. oe States Mfg. = Dept. E-843 4500 Mary 4 St. Louis, Me. “STAMME lfs Guse and Gire * You can be quickly ant if you stammer. Send 10 2ab-page ind book cents, coin or stam cloth bow snd stu t tells how I cured on Stammering Stuttert myself after St smmering and Stuttering for 20 years. BENJAMIN N. GUE , 2 11877 Boque Building, 1147 N. llinols St. ~~ —. 4&4 © Owe st nm «, — — - -— @- ~ —-_pit ee te aon eo me ok ee UU a eee ee oe ek 6 [6

Page 147

1930 ool in aes © -—F fied ini- elor . ine idu- ges, ink. May, 1930 N ew Ideas Sweep Movie Studios (Continued from page 144) which permits pictures for projection on the new wide screens to be taken upon film of standard width. Another advantage of this invention is, of course, that it would save the added expense of the double film. Working on the same principle as the distorting mirrors seen at amusement places, it condenses a double-width picture into a single width of film. An adjusting lens in the projection machine restores the picture to its normal proportions. While two motion picture companies are said to have adopted the Douglass lens, a technical man predicted to me that its applica- tion would not prove highly successful. Due to excessive magnification of the silver grains, he explained, the enlarged picture on the screen would be marred by coarseness and lack of detail. ND how does the Schufftan process work? Like many other discoveries it is so simple that the fact that no one ever thought of it before is a matter of amazement. An optical mirror, with its silvering on the front instead of the back, does the trick. Let us suppose that the scene to be taken is to repre- sent a cathedral interior showing the organist and choir. All that is built are two inexpensive sets, made of the usual canvas or plaster of Paris, depicting the immediate surroundings of the organist and the choir. In these settings, the actors “do their stuff.” An ordinary movie camera is used. Before it, the mirror is placed at an angle of forty-five degrees. At one side a transparency, model, or photograph of the cathedral interior is set up in such a way that the mirror reflects its image into the lens of the camera. But the silver surface of the mirror in front of the camera lens blots out the two small sets and the actors. Before the scene is shot an expert scrapes off enough of the silvering to let actors and real sets appear through the glass. The sets, photographed at a much great- er distance than the image of the model or photograph of the cathedral interior, appears on the film in exactly the same proportion. Thus the action on the film seems to occur apparently in the proper places inside the cathedral. A large, thin lens resem- bling in appearance and action a hugespectacle lens is placed between the transparency, photo, or model of the cathedral and the silvered mirror. It is ground so as to correct the focus of the near-by cathedral picture and make it seem, to the camera lens, to be as far away as the actors. This trick method of focusing sharply ob- jects at different distances from the camera is responsible for the success of the Schufftan process. ODELS were used in the early days i of the movies, but it was difficult to photograph actors at the same time. An im- provement was a method somewhat similar to the Schufitan process (P. S. M., Jan. ’27, p. 15), in which the upper parts of a cathedral, for example, were painted on glass and placed in front of the camera in such a manner that they appeared to be a continuation of the lower parts, which were actually built. What will be the next revolutionary change in the movies? Obviously, it will be practical three-dimensional pictures—that is, movies with true stereoscopic effect in which images have length, breadth, and depth as well. A few weeks ago, Dr. Donald Clive Stuart, pro- fessor of Dramatic [Art in Princeton Univer- sity, went so far as to declare that the present generation would see them. When I repeated his prediction to a motion picture engineer, he shrugged his shoulders and smiled. “Per- haps,” he said. ‘Who can tell?” POPULAR SCIENCE MONTHLY 145 R.T. I. QUALIFIES YOU TO MAKE MONEY ANDITS SERVICE KEEPS YOU UP-TO-THE-MINUTE ON R. T. I. THE NEWEST SIN }» AND TALKING BIC DEVELOBMENT 1. a R | : | A i 4 Al gi) ANSWER THE CALL! GET STARTED NOW! RADIO has leaped from the experimental stage to a gigantic industry, employin many, many thousands and loudly calling for MORE TRAINED MEN to fill well pai jobs. TALKING PICTURES have taken the country by storm, opening up many new good jobs. TELEVISION now comes with even greater promise of a large bens te of good paying positions for those who are prepared. A trained radio service man can easily make $40 to $50 a week and it is very common for a trained man with experience to make $75 a week and upwards. Many hundreds of trained men are needed for servicing and other radio positions now. Will you get ready for a good job NOW and step into.a Bigger one later on? You can do it easily. R. T. L HOME TRAINING QUALIFIES YOU QUICKLY FOR THIS BIG FIELD The Radio and Television Institute of Chicago was organized to train men at home in Radio, also Talking Picture equipment and Television. The R. T. I. course is easy, yet it is practical, thorough and complete. It was prepared and is supervised by one of the best known radio engineers and an advisory staff of men actively engaged with leading radio concerns. Are you willing to devote a little spare time at home? That’s all you need to quickly start in this great field on the right foundation. You learn with the R. , a +f testing and working outfits—on practical, interesting work. A QUICK RESULTS! EXTRA EARNINGS! You want to earn more MONEY, and want some of it Quick. The R. T. I. “Three in One” Home Training—Radio—Television —Talking Movies—will give it to you, because it’s easy, prac- tical, and is kept right up-to-date. In a few weeks you can be doing actual Radio Work, making enough EXTRA MONEY to more than pay for your training. In a few short months you can be all through—ready to step into a good-paying job or start a business of your owa. The R. T. I. Course of training is endorsed by leading radio trade associations— they want men and want them trained right. INVESTIGATE—SEND FOR R. T. I. BOOK NOW Get the facts avout Radio, Television and the Talking Pictures first hand,in the Big R. I. FREE BOOK. Learn what thi8R. T. I. “Three in Cpe’ Home Liiy — ean do for io Mail the coupon for FREE BOOK NOW. RADIO & TELEVISION INSTITUTE Dept. 35, 4806 St. Anthony Court, Chicago 5 lel aaa ee ce oneal eel oneal ened R. T. I. trains your head and hands for money-making radio work. RADIO & TELEVISION INSTITUTE Dept 35, 4806 St. Anthony Court, Chicago Send me Free and prepaid your BIG BOOK “Tune In On Big Pay” and full detatis of your three-in-one Home Training (without obligat- ing me in any way). THE R. T. I. ADVISORY BOARD—of weil hacen een actively engaged in the Radio Industry PD ddan dos Seen sect ov eNss dokbestebaas supervises the preparation, revision and rendering ee Te LRAEE! INS Sa AE of R. T. I. training service. i lia eee BORER. .bccccnasess A definite program for getting ahead financially will be found on page four of this issue. Want a Steady Gov't Job? $158 TO $225 A MONTH MAIL COUPON BEFORE YOU LOSE IT Franklin Institute, Dept. H-269 Rochester, N. Y. ! Sirs: Rush to me, without charge, ( 1) Full U porsiguazs telling how to become a Railwa’ # Postal Clerk; (2) send copy of 32-page book i “How toGet U.S. Government Jobs,” with list 4 of many Government positions obtainable. la Steady Work—No Layof's—Paid Vacations—Common Education Sufficient / Address. ...........-.00+eeseeeeeeee ne ceeees ®\) \\2ERAINED MEN oy, them om ani) So ee Ree

Page 148

POPULAR SCIENCE MONTHLY DOUBLE the earning power of your two hands by learning DRAFTING While you're looking around for a line of work that pays better—that offers a real future —why not at the same time— —consider a line like Drafting—where the work is interesting and pleasant—where your associates are the kind of real fellows you'll be proud to know—where positions are plenti- ful—where you'll have a chance to get ex- perience that will lead to positions as Super- intendent—Engineer—Contractor ? It won't take you any longer to learn Drafting than to operate an intricate machine. —but the Draftsman’s pay is 50% higher to double that of the expert mechanic. —simply because men who can create plans of buildings and machinery are doing a higher paid kind of work than the workmen who flew the blue-print—because in the Drafting they build things ‘‘on paper,” figure costs, estimate materials. A G d J b When you’re half way 00G JOD through the Course Ten BILLION Dollars is to be spent in new building construction—two BILLIONS for new electrical projects—BILLIONS more in manufacturing lines —that means THOUSANDS of new Drafti positions that have to be filled—so if you’ get ready we'll be glad to assure you a satis- actory position and salary when you finish. But you don’t have to wait until you finish to cash in—we'll help you get a good job when you're only half way through— Student Starts at $140 a month Arthur F. Saxon—formerly a clerk—only half way through his course writes concerning position we helped him get: ‘Am enter- ing service of Blaw-Knox Co. at $140 a month—certainly consider the cost of the course the best investment I ever made’’. l gee Aqpesiesn School : pt. D-548 Mail | Drexel Ave. & 58th St., Chica+o Coupon . sea e for ben ~ s Siti oontme 36 pag rafting Book, and te FREE me about your combined training Draft- | and employment service. ing | Book DN ietcicdnasescageuninconn | SO EEF —hictiaale e ss B.S. degree in Aero- nautical, Civil, Elec- trical, Mechanical, Chemical and Ad- ministrative Engi- neering. Intensive courses, half usual time. Students who left high-school can make up work. Liv- ing costs and tuition low. Enter classes Sept., Jan., March or June. Ask for catalog. 550 College Street, ANGOLA, INDIANA ,TRI-STATE | COLLEGE ' make the needed raw alcohol. Where America Gets Its Booze (Continued from page 21) tured alcohol had made that source ef- fectively expensive. Dr. Doran showed me figures to prove that the bootlegger then turned to the cheaper method of fermenting sugar or similar substances, distilling the product to rohibition officials believe that is what the vast majority are doing now. LCOHOL can be produced by the microscop- ic yeast plant from any ordinary kind of sugar—cane sugar, beet sugar, corn sugar, fruit sugar of any kind, waste molasses, waste fruit juices, and many other materials. Potatoes or | grain will yield alcohol after their starch has been converted into sugar by an enzyme called diastase. This is the purpose of sprouting the grain or “malting” in the old-fashioned methods of making whisky. There are also chemical methods of converting the starch into sugar, and all of these materials—potatoes, grain, sugar, molasses, and many starchy or sugary wastes—are used in one factory or another for the manufacture of industrial alcohol for legitimate uses. Recent seizures by the prohibition author- ities, said Dr. Doran, indicate that the present chief source of alcohol for the bootlegger is — sugar which is fermented with yeast and then distilled. | According to the old-fashioned methods of making distilled liquors, this process would yield a rather inferior kind of rum. But the bootleggers use a modern chem- ical still and “rectifying column,” exactly like those developed for the legitimate alcohol industry. As a result the product is not weak rum, but is concentrated, reasonably pure alcohol, from which the local “distributor” or “jobber” can make rye, gin, Scotch, wine, or the “finest imported liqueurs.” Statistics of present-day use of alcohol are admittedly very inaccurate. Dr. Doran’s office estimates the present production of illicit alcohol at about 30,000,000 gallons a year. I should be inclined to put it a little higher. D* DORAN convincingly proves that of this thirty or thirty-five million gallons of annual American booze at least 25,000,000 gallons is coming from distillation in large, hid- den stills. Chiefly, the material fermented and distilled is sugar, although some grain, some potatoes, some fruit juice, and perhaps a few other materials may play small réles. Sugar is the big source of supply for the bootlegging industry; the chief basis of their $3,000,000,000 business structure. Some industrial alcohol and denatured al- cohol probably is still being reconditioned or diverted. For example, several bootlegger- manufacturers have been caught buying cheap toilet waters or lacquer thinners and solvents, removing the oils by chemical and distillation processes, and adding the alcoholic product to the bootleg stream. Perhaps two or three ‘ million gallons oi alcohol came from this source into the bootlegging industry last year. The only other prominent source is illicit importa- tion and “rumrunning.” This is spectacular but from the standpoint of the bootleg barons it is almost useless. Dr. Doran does not believe that mere than two million gallons a year enter America this way. I have been given larger es- timates by others but I agree with Dr. Doran. This fact may have interest for intending purchasers who hear in New York the story that “this just came off a transatlantic ship,’’ or in Detroit the tale of how the bottles that are offered were “just run over the river last night.” Of course such rum running does hap- pen and I would not be surprised to learn that occasionally a steward slips ashore in NewYork with a bottle of real European stuff. But were rum running or Euro- (Continued on page 147) fearnAVIATION WHERE LINDBERGH_ STARTED! a We Can’t Supply the Demand AS for Lincoln-Trained Men SSS Executives of big aircraft companies and air- gests write us a day for mechanics and pilots, e haven't enough graduates to supply them. Come to the Lincoln School—where Lind learned—and let us train you to fill one of these Big Pay jobs. fou get thorough. Practical mechanic and jlot training. Work on actual planes and parts urnished by the Lincoln Aircraft Co. Go right up into the sky. Our planes and pilots are licensed by the U. S. Dept. of Commerce. Write for details today! LINCOLN AIRPLANE SCHOOL WHERE LINDBERGH LEARNED 210 Aircraft Bldg. Lincoln, Nebr, the Craters ae the MOON! ASTRONOMICAL AND TERRESTRIAL See TELESCOPE Lendeeien Pacnreces ae Viess Sconnmes, Ocean ne Astronom - Enlarged eoope. SEs thousands of mies 30 Timeet away. Make sun, moon, planets, stars your next door neighbors. Moon Craters, Sun Spots, Eclipses, Comets enlarged 30 times. Strange thrill friction adjustment for focusing. Adjustable bracket oad eg = can te fastened to chair, fence, ranch, Finest materials, Will fast lifetime. 5 Days’ Free Trial Rush only $1.00 b balance (82.95 plus pasteay when postman delivers, re cag If not delighted. re. urn telescope and money be refunded. = f Hours of fun look- fa ng at scenery, games, ‘bathing beauties. Great for trips and voyages. Made like telescopes used in observatories. Gots wrote, ‘‘Moon seemed 1 Mote! my Diameter 2 inches. Special Roll-O Specialty Co. A i D Dept. E-354 Charge 25c to look at the moon 220 E. 3rd St., Ci innati, 0. LEARN AT HOME To Make Crowns, Plates, Bridgework, etc., FOR DENTISTS New, easy practical way to learn mech- anical dentistry at home in spare time. Full equipment of tools and materials included with course at Do extra cost. Low tuition. Easy terms. ’ | Write for FREE BOOK “AR meq that describes this money 3 u ae maki Profession and as sae 6details of our easy-to-learn / “e i sam home study course and * =a special offer. Write today. McCarrie School of Mechanical Dentistry 1340 S. Michigan Avenue Dept. E-105 Chicago,i, in Today — Write ier my 4 — BOOS. Ican ea penman of you at home during spare time. W) ite for my FREE BOO K, **How to Seoeme 4 how others mastered penmanship by the Tamblyn System. Your name will be edentle written ona card if you enclose stamp to pay postage. Write to- day for Book. FW. TAMBLYN, xanst2 Eh He F's. a. Government Positions Clerk Carriers, Rural Carriers, Railway. Mail Clerks, Postmasters, Department Clerks, and many others. Splendid salaries, easy work, vacation with pay. Only common school education required. Examinations often. Send for our Civil Service Catalog No. 7. COLUMBIAN CORRESPONDENCE COLLEGE, WASHINGTON, D. C. 100% improvement Guaranteed Send today for f Yoleo Book teling abou New SILENT Method of gualities.. “Banish buskinees and’ b to sing with greater ease. 100,679 tm: today for f. book] ' Decbiets am voles touinies onesie ne er PERFECT VOICE IN: Dept. 1922 Sunnyside Averthiese Complete 110-volt Electri¢ ) 2) & Hew we: 9 Cen Light Plant. Ideal for Farms, Camps and Summer Homes- +139 Runs household appliances, Install it yourself, Wiring, Fixtures and Lamps for 7 rooms, $17.50. Also larger models D. C. or A. C. Write for ,circular-D. W. ONAN & SONS 307 Royalst Minneapolis, Minn. ANYWHERE in a Ue eee eee ee em OO w= 4. 8 — — aS &

Page 149

‘, 1930 May, 1930 POPULAR SCIENCE MONTHLY . 147 F Where America Gets Its Booze (Continued from page 146) an steamships to bring into the United States each year all the alcohol that Americans drink, there would be little room in the steam- ships for cargo, and tourists would be crowded from the roads across the international bound- ary. . ‘ — | The bootlegging industry is beginning to sed | realize the weakness of this claim of importa- te for | tion and to sense the value of the well-tested | business policy of always telling the custcmer OL the truth. While getting together the facts for this article I found a reasonable sprinkling of bootleggers who said frankly that their wares were made in America from raw alcohol, but : that both alcohol and wares — good. . The question of how much booze do Ameri- Coo 'f 0) cans drink is just as important as where the A UN. DREDS LY liquor is coming from. Do people drink more | S12 > iL RAINED EN ARE See or less than before prohibition? .. Day A KING ,, 60 s —— tee M: to100 A WEEK niarged - . 7 * gs m, vy. Ta Times | NACCURATE as are all present statistics ° inne a aor t 7 Why don’t you get into Electricity, too? It’s today’s great ustment fo _and estimates of alcohol consumption, they §akorne sé Opportunity for you and every other man who is sick and tired ° fastened to still permit a rough answer to this question. wrk, Okie: News ‘> of struggling along on small pay. Hundreds of “Cooke Trained wilt fas Americans are drinking less; about one fourth (2s ene te On plement pce on they started now make as much, in fact, as they drank fifteen years eat. : gatafadgg Tin a ese he I ee writs || sEnhoic dems which gencraly are edmited | cove ttt sa Seeds ous postage) alconolic 1 j " Learn with the famous L. L. x lined, re to be least harmful; that is, wines and beers. Ticket” Method. It’s simple, it’s thorough, it's pone Rang ice a Of hard liquor, Americans are drinking about Fe ee eee ee Ree: Tee BS We Sone saan te your sialty Co. three fourths as much, per average individual, given to you without extra eons. ‘And it’s done in your fen age ag 384 as ad did — prohibition. > in sah without quitting your present job or losing a single hour's pay. incinnali, 0. These conclusions are not Dr. Doran’s, al- though I think that he might agree with them. y oe SEPEREENGE NOT NEEDED VIE They are based on official statistics plus cal- education to learn’ Blectricity the Ly L> GOOKE, Wass if nos culation which I have made of the average an- can read and write, that’s enough. This great Training is amazing- , ete., nual use of alcohol per individual over fifteen | ho nage eg oe 8 BE hap pide ve pheow dade ay AaB TS years old in the continental United States. Cor- that has put many men on Easy Street; it’s the ‘Training for } you. rection is made, of course, for the increase of . oo population between preprohibition times and GET STARTED -- MAIL COUPON tra cost ae, Bn ae eee to G50 9 wack io hal ome af Mine ton aie Pan ie terms. over fifteen drank about one and four tenths : Bes apy aS 8 sme ” BOOK gallons of hard liquor a year and about twenty- _— = yr ogo ——— po gg . five gallons of beer or wine. Reduced to the coupon for Big FREE Book, “Secrets of Success in Electricity.” -to-learn _ of contained alcohol, the average annual | Mail coupon now. ye alcohol ration, before prohibition, was about coin one and seven tenths gallons. L. L. Cooke ScHoot oF ELECTRICITY hicago, lM. Now, as closely as I can estimate it, the same Dept. 35, 2150 Lawrence Ave., Chicago, Ill. average individual over fifteen years old is drinking about one and two tenths gallons of slightly more diluted hard liquor each year and less than a quarter of a gallon of beer and wine. bebe. S82:558 Cewrence Ave. Chi m. This merely confirms what is evident to general of nd me entirely free and fully prepaid: Yorut your Home observation, that the bootlegging industry Study Course in Electricity. 10 Become | does not care to handle bulky, easily spoiled PEON By” mnt ae Seis OPO OPPO Che ae 1e Tamblyn | products like wine and beer when it can handle ae eageantnsncsceotagstode te . . Weite to- | the concentrated, stable industrial product of Smidennof Canada may end cougon te BA, Harrow, Soe , R ive. 7 Medbury Lane, East,Windsor Vut., Causua, BIe's a. raw alcohol. , EDUCED to alcohol, present~ drinking ons gives the average American, I estimate, an : annual dose of a little over four tenths of a i Clerks, § | gallon as compared with the preprohibition | record of about one and seven tenths gallons. | That is the measure by which prohibition | actually has cut the drinking of alcohol. In money, of course, there has been an in- crease instead of a decrease. Figures which I have prepared as carefully as possible, but which still are no more than rough guesses, convince me that the booze bill of the average | * American adult before prohibition was about | . y others. ay. Only 1inations g No. 7. LL This swift and sturdy bicycle can be yours. e ead Bm | $17 a year. At present I believe this bill to be | , our tone ie greatest J 13-65 ae Electric Farms, Homes. We need a boy in your neighborhood to de- liver the American Magazine, Woman’s Home Companion and Collier’s, The National Weekly, to regular customers. Hundreds of boys are getting bicycles like this one, and also cash commissions and other big prizes. You can easily do it, too. at least $35 a year, something over twice as much. That is how the bootleg barons get three billion dollars a year out of this youngest of American industrial giants. BOYS—MAIL THIS COUPON AT ONCE Coming soon—a fascinating article on modern railroading, made safer and more luxurious every day by new won- ders of invention and engineering. An expert tells in a forthcoming issue how the romance of the Iron Horse has led Mr. Jim Thayer, Dept. 144 The Crowell Publishing Co. Springfield, Ohio Dear Jim: I want to earn money and win prizes. Please start me off as a salesman. to the steel-paved highways of this BD TOMER; . . 0.5 «ds Civgbdctevnaiceveebe cod ouenane to paeie a > oo the country’s map for once by a a et a a BINED. ooo ccc conc cdvebendeseccessuseesieessssb seas — coupon. (4 A A IS oo vic cesar cen meas poe raeieteckin NG Sab tweed cewewes

Page 150

cone eeereseninces senleneereteceeenmentenmmsnnns in. ih > saacieen? atktdian Aton eee ie) oy aia a i cereale eeu Ay seaditeenen teerttain ecpitiamdimdmranes nee Se dundee me ee ae ee ed ——— 5x web te 148 WHAT xevaenw WANTS TO KNOW. READ A BOOK A MONTH PAY $1.50 A MONTH Start progress today! Subscribe to Audels monthly book service. One subject mastered may be worth 10 . times the value of the whole set to you. Keep up to date. Send coupon today and start this valuable electric course. Satisfaction Guaranteed. & Sust Published! Exact Information from AtoZ. Audel’s NEW Electric Library—for bome study and ready reference. Latest information from foundations of electrical practice to newest applications. A 12-book series, pocket-size—7 books now ready; 6 in prep- aration, EASYto learn; a step-by-step progressive course, written in plain language, with questions and an- swers, fully illustrated. EASY to read; pocket- size, flexibly bound in red and gold. A AUDELS NEW ELECTRIC LIBRARY gives inside information based on the code; questions and answers on thousands of electrical subjects in- cluding: ism, Armature Winding D-C Motors, Maintenance and ‘Trou e Shooting, Tests, Storag: » Alternating Factor, Tra A-C Mo- tors, Wind! Conv Switches & Fi R e ers, Meters, Power House, Light & Power bay = '° lectric ways, Gas Engines, Auto & Aero Igni- tion, ead Lig y = ‘elegraph, Motion a X-Ray, Welding, Pumes, Compressors, Appils ances, An Electric Calculator, Practical Ma matics, A New Electric Dictionary. ~ — MAIL THIS COUPON TODAY _ _ THEO. AUDEL & CO., 65 W. 23d St., New York, N.Y. Please enter my subscription to ““AUDELS NEW ELECTRIC LIBRARY,” 12 books. Mail one book a month and as received I will mail you $1.50 promptly. Name nm Address Occupation_ - Employed by 5730 Become a musician so quickly as to astound everyone. Learn by play- ing real music—instead of tiresome “exercises.”” You'll soon become the most popular person in your ‘‘set.” New Easy Method Nothing else like it for thoroughness and rapidity. So simple that young and old find it easy to play with amazing skill. No “trick music’’—but ac- PICK YOUR ae notes, — quickly right n your own home. ees FREE BOOK and Demonstration Lesson Piano Violin regan Glazinet | offer this wonderful musical op- Harp portunity. Send for them toda *c before copies are exhausted. You’ Pice be astounded by this easy, rapid way to become a veritable master Piano of your favorite instrument. In- Voice ae struments supplied when needed. Drugee and Traps SAS SEt, . mamcow= omatic U. S SCHOOL OF MUSIC, Banfo Pisctram 85 Brunswick Bidg., N. Y. City gtr Send me your free book ‘‘Musi Sane Lessons in Your Own Home,” Catign and Ber with introduction by Dr. Frank Crane. Also Free Demonstration ition Lesson. This does not put me under any obligation. DP Uschthe ensabaedreUesedeeredeeseuncedscecescus Sin: cs 3h a 08 ehte-d aw oes Minin aide aati N44 6a 0.00000 Have you EE Being need ébs6.00k seed sk ee POPULAR SCIENCE MONTHLY Hypnotism Fake, Says Magician (Continued from page 25) Catalepsy, or muscular rigidity, is accom- plished by the professional hypnotist in the following manner: A “horse” stands in the center of the stage. After stroking the man’s forehead and temples, the ee suddenly shouts “Rigid” in a voice that frightens all the women and children in the audience. The “subject” straightens and is about to fall when the hypnotist seizes him. The man is laid across two chairs, his ankles on the back of one, his shoulders on the back of the other. Three or four people stand on top of him while he lies motionless, supporting their combined weight. The “professor” apparently has en- dowed his “subject” with superhuman strength. Naturally, he has done nothing of the sort. The “subject” clutches the sides of his trousers near the knees, holds his arms rigid, and keeps his back arched. He thus becomeg a human cantilever and the weight can be supported. OSTHYPNOTIC influence and hypnotic anesthesia are among the favorite stunts of the fake hypnotist. The best-known “post- hypnotic” trick is performed in the “ window- sleep” experiment. The hypnotist puts a “subject” to sleep in a store window and lets him remain there from six to ten hours. This may appear wonderful to the man in the street, but it is merely a case of lying still for a long time. When a crowd has gathered, the hypnotist enters the window, strokes the “subject’s” forehead, leaves the store, and walks across the street. In a moment, he slowly raises his hand. The “subject” does the same. Pres- ently, the hypnotist lowers his hand. The “subject” does likewise. Amazing! But what is the secret? When the hypnotist finishes stroking the “‘subject’s” brow, he begins counting to himself, as the “subject” also does. They have practiced counting at the same speed. When the hyp- notist is across the street, he reaches one hundred ir his count. . He then raises his hand and the “inorse” almost immediately follows suit. As soon as ine “subject’s” hand is fully raised, they start a new count, and the hands are lowered at another prearranged number. The possibility of using hypnotism as an anesthetic is one of the oldest claims made for it, and the one that has given rise probably to more false and exagg-rated ideas than any other. Through training or will power, people can harden themselves to withstand considerable punishment. Prize-fighters and football play- ers are noteworthy examples. Considerations that are for the moment more important than pain, such as money or glory, cause suffering to be minimized or temporarily forgotten. gp explains the demonstrations by pro- fessional hypnotists who push needles or skewers through the “subject’s” flesh. It is possible to find a person who will not mind this much even on the first attempt, and who, having undergone it a number of times, become accustomed to it—particularly when financial returns are involved. A few years ago, an Egyptian fakir came to America and won notoriety by pushing skewers through his arms and cheeks. When he gave this demonstration at a university in Phila- delphia, a professor of psychology classed it as “autohypnosis,” explaining that the Egyp- tian was his own operator and his own subject. But it was no such thing. The fakir pos- sessed a temperament which minimized pain. Let a hypnotist work on a man of this type, telling him that he will not feel pain, and it is probable that he will suffer little in the skewer test or possibly in a (Continued on page 149) May, 1930 AVIATION Information F R E E Send us your name and address for full information re. garding the Aviation and Airplane business, Find out about the many great opportunities now open and how we prepare you at home, during spare time, to qualify. Our new book Opportunities in the Airplane Industry also sent free if you answer at once. AMERICAN SCHOOL OF AVIATION Dept. 1365 3601 Michigan Ave. CHICAGO INVENTORS facts before applying for Patents. Our book Patent-Sense ——. who derive larg- est profits know and heed certain simple but vital gives those facts; sent free. Write LACEY & LACEY, 8 F St., Washington, D. C. Established 1869 PATEN T oiwventi INVENTIONS Edward Gottlieb ATTORNEY IN PATENT CAUSES 5 Beekman Street, New York Inventions Developed=Representative for Blair Tool and Machine Corp. MAKE MUCH MONEY Making and Selling Your Own Goods. For- mulas by experts. Manufacturing Processes, Trade Secrets. All kinds. All lines. Auto- mobile Specialties. Cleaning and Polishing Compounds. Food Products. Toilet Prep- arations, etc. Send for interesting catalog, special circulars, FREE. C. THAXLY CO., Washington, D. C. EXGEIANEERIAG..... ELECTRICAL, MECHANITAEL + STRUCTURAL 1 ad ARCHITECTIBE intensive, Practical, Technical Courses. Decree in 2 years. Diploma in 1 year. Special short courses 6 weeks to 4 months in Electricity, Radio, Power Plant, Electric Re- frigeration, Armature Winding. Wiring, Testing. Drafting, Welding. Low Tuition. Expert Instructors. ‘Extensively equipped laboratories. Free life-time employment service for graduates. Part-time work while attending. ‘rite for new free illustrated catalog civing all facts. 29th year. FINLAY ENGINEERING COLLEGE 1001-A Indiana Ave. Kansas City, Mo, AGENTS 500% PROFIT GENUINE GOLD LEAF LETTERS Ry Guaranteed to never tarnish. Anyone can ¢ 3 put them on stores and office windows Enormous demand, large profits, Paul Clark says: smallest day $28.70. R.L. Reel made $920 in two months. Write today for free sample and liberal offer to general agents. METALLIC LETTER CO., 433A N. Clark Street, Chicage. DRAW CARTONS Turn Your Talent Into Money Cartoonists earn from $50 to $250.00 per week—some even more. Remark- able new Circle System of Drawing teaches you in half the usual time. Send for bookiet and sample lesson plate explaining full details of the Course. No salesman will call. THE NATIONAL SCHOOL OF CARTOONING 615 Penton Building Cleveland, Ohio CANDY costs 14c—sells for 600 lb. Make it at home, sell stores. Ladies and men. Pr ~ money-making plan, taught (by =] mail) by merchant 35 years’ suC- cessful experience. We furnish — ii] tools. Write for Free_Book. Capitol Candy School Dept. B-3006 Washington, D. C 8 In two-tone Artcraft Binder (looks like leather—lasts for csorer with the name be the magazine stampe Popular ou oa Cong This inde ; will hold six copies of t! Science magazine, and new copies Monthly can be slipped as easily a8 Price $200 inserting a letter in af Postage Prepaid envelope. Poputar Science Pusiisuinc Co. 381 Fourth Avenue New York City

Page 151

, 1930

May, 1930 POPULAR SCIENCE MONTHLY

—_ Hypnotism Fake, Says Magician (Continued from page 148) minor operation. Tried on an intelligent per- son with a sensitive nervous system, the experiment will fail. Through hypnotism, Professor Wells states, “there may be produced changes of physio- logical processes not subject to voluntary con- trol, such as alterations in the pulse rate.” That is another trick of the Egyptian faltien. Some of these “miracle men” can cause their pulse to die away in a manner highly perplex- ing to physicians who have tested it. The stunt is ridiculously simple. Usually, it is accomplished by means of a block of wood beneath the armpit. Pressure of the upper arm against the block causes an immediate drop in the pulse beat. Another famous “‘hypnotic” stunt is that of lying on a bed of spikes and allowing someone to crack with a sledge hammer a huge stone resting on the performer’s chest. tribution of weight makes the bed of spikes only slightly uncomfortable. As for the smashing of the stone, its size and weight, more than 250 pounds, absorbs the blows of the ten-pound sledge hammer. Most spectacular of these ieats is the “living burial,” in which the fakir, in a coffin, is cov- ered with earth. Sometimes the “miracle man” is lowered to the bottom of a river. These ordeals last an hour or longer. With- out air, it seems impossible for the man to live. Hypnotism? Hokum! The real explanation is that a person, lying quietly, and breathing very slowly, consumes a comparatively small amount of air. coffin is sufficient for a prolonged repose. notism have invariably hesitated to claim group hypnosis as a possibility. Professor Wells describes a phonograph record reproduc- ing “‘a series of sentences spoken in a monoto- nous and commanding tone to bring about the hypnotic condition in those who hear the record.” This not only supports group hyp- nosis; it upholds group hypnotism without an operator. It reduces the “science” of hyp- notism to a mechanical operation. can bring about a hypnotic state, so can the music of an orchestra, the beat of a distant tom-tom, or the whistling of the March wind. These sounds do affect the mental reactions of some of those who hear them. They kindle the imagination and often excite the emotions. They do this, not because they are possessed of some mysterious hypnotic quality, but suggestion. Since it is my business to present new mysteries to the public, I have studied and investigated hypnotism for many years in the hope of finding something really remarkable. But all so-called trance conditions, catalepsy, and posthypnosis that I have ever seen demonstrated obviously were fraudulent. In order to receive recognition as a scien- tific procedure, hypnotism must meet its champions’ claims that, through its aid, an operator can place a subject i in a trance condi- tion in which he will obey commands or sug- gestions of the operator. I dispute such claims and challenge anyone to prove them with a reasonable number of subjects chosen at random before a committee of capable and impartial investigators. Until this is done, I shall continue to be- lieve that hypnotism is the same hokum today that it was when F. A. Mesmer, the first professional hypnotist, or “mesmerizer,” startled Paris with his demonstrations of “animal magnetism” at the end of the eigh*-

eenth century.

Even the most stalwart champions of hyp- | | |

STONISHING? Not atall. Proper dis- | The cubic capacity of the |

F SPOKEN words on a phonograph record | because the human mind is susceptible to |

Why work all your life for small pay and with little chance for a raise or promotion? Let me train you for Higher Class Work and Better Pay. Get my Pay-Raising Plan—NOW. I'll send it to you FREE. It will convince you and show you a way to build a big future for big pay, on clean work leading to salaries of $60-$70, and up to $100 a week salary. All buiidings, machinery, automob motor busses, air- ing and con- ships, electrical apparatus, all manu struction of any sort, depend upon I train you by mail in your spare time. You keep your = while — I give you an opportunity to earn Mail This Coupon If You Earn Less Than‘*70a Week Mail this coupon now, and T will send you “My Pay-Rai Paw ~ praftne 5 Book and Dra’ postpaid and or Dobe, 5%; Chicazo 4951 Lawrence Av.

© “You’ stot, your =the Ode

me when I train

with a foundation orig- you on inally os Deaftemen. work for When trained by me, I help you get a job without More Pay! charge. Employers of draftsmen come to me for Steady Pay! competent Se at $60 straight x No previous experience is necessary. You do not need to bit ont cee eR rane acs a Su Rat HOSES TPO BY a

“FREE” Pay-Raising Plan | ENGINEER DOBE, § 1958 Lawrence Ave., Div. 13-65,

5 Please send free of all “M: -Raising Plan”, § also FREE Drafting Book mort, tay Par Retsiog Pea’ 8 ALL FREE. = . Name Age...-< ' : I ce ccccmnnitieninciatinilititininitiintiinndinininhisinlrsdiaisgtinstitlandatied “ + Be

EARN wid bo TO $200 WEEKLY ya in ope Fear,

Substantial Advance Royalties are paid on work found | lication. = y= the words or music for songs may submit work for Lames examination and advice —_ ceunnecessary.New demand by Talking Pictures”, fully seribed in our free book. Write rite dae Today—Newcomer Associates 758 Earle Building, New York, N. Y. ‘ou Anyone Svs

Saar 0 POVER Me Sent for Only $joo An educations! and entertaining instrument that ¢n- ables all to see and know life invisible to the naked galore TO

m use ee physicians, scientirts, ete. Now y $3. ‘ould easily sell for $10 and $20 more. Ad fistable lens of 240 power! Send only $1.00. Pay balance ($2.98 plus ) when postman delivers. If not satie fied, return in 5 daysand moncy will be refunded.

IDEAL FOR = Dealers and Teachers be wonderful pict Write for Our ie reidy ry Frepestient

before has such a wonderful inetrement hoon offered at such as amazingly low price of $3. R. B. SPECIALT Y COMPANY cept. E-350 220. 3rd St., Cincinnati, Ohie

‘hen TRAVEL FOR Railway Postal Clerks

vate Siento Work — No pel te — Paid Vacations & Many Se Government Jobs Obtainable < EN—WOMEN 18 to 50 2

“UNCLE SAM” $158 to $225 a Month MAIL COUPON BEFORE YOU LOSE IT

FRANKLIN INSTITUTE, Dept. H-271 Rochester, N. Y. Sirs: Rush to me without charge—copy of 32-page book, “How to Get U. 8. Government Jobs,” with list of positions dotainable and full particulars telling how to get a position. : ° Pa Pa

Page 152

J i =——<—--—o— Te andar tegiees cee oe / Tee eee Fyre ye a

‘TAKE THE BOSS’S JOB AWAY FROM HIM” “Let it be your dominant aim to take the boss’s job away from him. Every boss is looking for a man, or men, to shoulder his burdens. Be that chap.” Those are the words of Eugene G. Grace, President of the Bethlehem Steel Corporation. The day is coming when your present boss will move on, and somebody will step into his place. Is there any reason why it shouldn’t be you? Don’t sit still and wait. Go after that job of his! If you are not the best qualified man in sight, you can be. The International Correspondence Schools have courses of instruction in exactly the subjects you need, to advance in your present line of work—courses that will fit you to handle the boss’s job. In spare time. right at home, you can prepare yourself for promotion. Thousands of I. C. S. students have proved it. They’ve “‘taken away’’ so many bosses’ jobs that today employers look to I. C, §.-trained men for their younger “rn your own work isn’t my in this coupon, write us on it. 231 standard I. C. S. courses are open to you. Mail the Coupes Today! _—_-_e_—_—_- ee ee eee eee INTERNATIONAL. CORRESPONDENCE SCHOOLS “The Universal University” Box 7661-F, Scranton, Penna. Without cost or obligation on my part, please sen! me a copy of your 48-page booklet, “Whe Wins and Why,” and tell me how I can qualify for the sition, or in the subject, before which I have marked an e TECHNICAL AND INDUSTRIAL COURSES Architect Automobile Work Architectural Draftsman (J Aviation Engines {_] Building Foreman Plumber and Steam Fitter Concrete Builder Plumbing Inspector Contractor and Builder Foreman Plumber Structural Draftsman Heating and Ventilation Structural Engineer Sheet-Metal Worker Electrical Engineer Steam Engineer Electrical Contractor Marine Engineer Electric Wiring Refrigeration Engineer Electric Lighting R. R. Positions Electric Car Running Highway Engineer Telegraph Engineer Chemistry Pharmacy Coal Mining Engineer Navigation [] Assayer Iron and Steel Worker Textile Overseer or Supt. Cotton Manufacturing Woolen Manufacturing Mechanical Draftsman Machine Shop Practice Toolmaker Patternmaker Civil Engineer Surveying and Mapping sa—enge OJ Fruit Growing Bridge Engineer Poultry Farming Gas Engine Operating Mathematics ([) Radio BUSINESS TRAINING COURSES Business Management Rusiness Correspondence Industrial Management Show Card and Sign Personnel Management Lettering Traffic Management Accounting and C. P. A, Coaching ce Cost Accounting Railway Mail Clerk Bookkeeping

Secretarial Work _}Grade School Subjects Spanish [ French [} High School Subjects Salesmanship L}fllustrating () Cartooning Advertising || Lumber Dealer MI ciiiditasiiistaiidsaildctiind Street eB ictscintntncosiconsntesanscncsectedsenenese Gi ccicisdindiisnaicnssceseintdnunecsetadadabinsel State Ro nkies sc nvsccesicecas If you reside in Canada, “send ‘this coupon ‘to the International Correspondence Schools Canadian, Limited, Montreal, Canada

RING” E NGINEE CURE oer position or a business of your own. 7 haa dollars spent last year in one of these alone. Train here in Chicago, America’s in- dustrial center. 1, 2 and 3 year courses. Diplomas and B; 8S. . Special 4 months’ practical course in Drafting. Other short courses. Earn while you learn. Enter any time. Day and evening classes. No time wasted. Free Employment Bureau. Low one terms. Athletics. , Successful graduates everywhere. Free 80-page “‘Blue Book.” Address the President, Chicago Technical College, Dept. E 83, 118 East 26th Street, Chicago, Ill.

POPULAR SCIENCE MONTHLY

Sugar from Sunflowers (Continued from page 55) But it was one thing to find it and another to get it out by a cheap process. The Bureau of Standards experimenters knew they must find a way to extract it with water instead cf with alcohol, as had hitherto been done. This had Icng been considered impossible. Bates himself took charge of the task. Into a laboratory filled with expensive crucibles and retorts he brought a small common ice cream freezer. First, in a vacuum, he boiled down artichoke juice until only about ten percent of moisture remained. Then he poured the thick syrup into the ice cream freezer. Instead of freezing the hot syrup, the ice cream machine was arranged to cool it gradu- ally to rocm temperature. The solution was “seeded” with a few crystals of pure levulose to help along the crystallization of the rest. A sample observed through a microscope showed that more crystals were forming. When the temperature had dropped from one hundred and thirty to about eighty degrees, the cvlinder was opened. It was full of crystals of levulose. The impossible had been done. N THE strength of that experiment and others that followed, the Bureau built its small-scale plant which until recently has been the scene of the tests. One of the first achieve- ments was the production of 100 pounds of pure, hard, refined levulose. Of this feat, Bates says: “Probably no development in many years has opened up such possibilities for pro- foundly affecting man’s food supply.” In the new plant which the Bureau is erect- ing, an attempt will be made to carry out a “continuous flow” process of mass production such as present-day sugar factories use. It will make hard, refined fruit sugar or levulose. This new sugar can also be prepared in syrup form. Stop That Honking! (Continued from page 74) asked Gus. ‘“ An auto horn is a warning signal and a warning signal ought to warn and not play pretty music. Of course, there’s no sense in having a horn so loud and rough that it

May, 1930

Join the Ranks of the Successful Aviators

Who win their wings at Marshall Flying School,X°: The Original “College of the Air” Marshall training fits students for positions of leadership in Aviation. Enroll now and lay the ae for a successful future. ices are surprisingly low. SPECIAL TEN HOUR FLYING | iT sae aoe parry $ 200.00 PRIMARY AVIATION COURSE..... §$ 275.00 SPORTSMAN’'S ee (Qualifies for private pilot's license) . $ 450.00 PROFESSIONAL COURSE’ (Qualifies for limited sommerael license)....... $ 875.00 TRANSPORT C RSE (Qualifies for epee spie $2500. 00 MECHANICS COURSE............. 95.00 WELDING PS H 135.00 Clip and mail the coupon ae Join the ra of success. MARSHALL FLYING SCHOOL, Inc. 100 Barling Lane, Marshall, Missouri. MARSHALL FLYING SCHOOL, 4 100 Barling Lane, arshall, Missouri. I am interested in aviation training. Please send without obligation your descriptive booklet, ‘Win your Wings.”

scares a man half to death, but we’ve got to | remember that when the difference between hearing the horn and not hearing it may be the difference between life and death, there’s no sense in taking a chance on a soft sounding horn.” “There’s something in that,” admitted Blainfield. ‘‘Tell me, Gus, which kind of horn is better, the motor-driven or the buzzer type? ” IX of one and half a dozen of the other if they’re both kept in good condition,” said Gus. “Of course, any horn ought to be quick on the trigger. It ought to start making a loud | noise the instant you thumb the button. A

fraction of a second delay may be just enough to cause a crash. The buzzer horn starts instantly, though there isn’t much difference, nowadays, because motor-driven horns are built so that the armature jumps into action real fast.” “Why wouldn’t it be a good idea to have two horns? Then if one broke the other would work,” Blainfield suggested. “There’s only one objection to that,” Gus replied. “If you had the two horns working from the same button a break in the wiring would put them both out of commission. If you had them work from two different buttons on different wiring, you’d probably forget to press the other button if the first horn didn’t work. Anyhow it sure is bad medicine to drive so you have to depend on the horn to keep you out of trouble.” | | | | | \

Learn by Doing That’s the way we teach and we do more—we give the student a thorough training which will insure his success in after life. No field offers such great possibilities to ambitious men as the ELECTRICAL FIELD. You must however be practically trained before you can reach the harvest of your knowledge. We teach you electricity by giving you the actual work to do Every branch of Practical Electricity is so thoroughly and so personally taught as to place one who graduates from our school several years ahead of the experienced man in the field who has not had special training such as we give. Write for our Free Booklet today, or call at the school and get full par- ticulars. School open all year. THE NEW YORK ELECTRICAL SCHOOL 40 West 17th Street, New York City \. : 3 x . — v 7 : — —z

“Training for men of am- — and limited time. Electri ical oncise, comprehensive course in Theoretical and Practical Electrical including Math- Engineering = ematics and Me- hanical Drawing. Students construct motors, install wittes, test elec- om Lp ye 3 4 jfhoroush course designed to be “THIRTY-SEVEN™ YEARS, of successful experience assures you maximum training in minimum time. Send for free catalog BLISS ELECTRICAL SCHOOL 104 TakomaAve., Washington, D.C.

id

Page 153

[ee ef FF ee $3883 $$ &8 ive th- fle- ec- mé. »L }.C. Just Across Street U.S. Pat. May, 1930 POPULAR SCIENCE At the right is a view of my drafting and specification offices where a large staf oc experienced experts is in my constant employ. My Offices From Office ee Protect Your Ideas Take the First Step Today—Action Counts If 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 proceed in the quickest, safest and best ways in preparing an application for 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. It is probable that I can help you. Highest references. But FIRST—clip the coupon and get my free book. THAT right now, 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 establish its date before a witness. Such evidence may later prove valu- able to you. Simply mail the coupon and I will send you the booklet, and the “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 without charge or obligation. Clarence A. O’Brien Registered Patent Attorney Member of Bar of Suvreme Court of the United States; Court of Appeals, District of Columbia; Supreme Court, District of Columb‘a; United States Court of Claims. PRACTICE CONFINED EXCLUSIVELY TO PATENTS, TRADEMARKS AND COPYRIGHTS MONTHLY 151 All drawings and spec- ifications are pre- pared in my offices. nventors Unite for There, Free Books Mail this Coupon Now ‘ CLARENCE A. O’BRIEN Registered Patent Attorney 88-X Security Savings and Commercial Bank Bldg., Washington, D. C. =OR = ‘Suite 1106 Woolworth Bidg., 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. PPPS EY Te Ty eee ee ee DI, 5 hE ESS Pe oe a ee bree se eee ee (Important: Write or Print Plainly and Address Office Nearest You)

Page 154

Say eet ara ae os rons ian ea ate TT Pea es 152 Do you want to have your own cash business? Here’s your chance to do it and make big money, too. Morse earned $1520 in five months. Hun- dreds of others are making big profits. beg Electrakeen Lawn Mower Sharpener Sharpens all kinds of lawn mowers the factory way in from 15 to 20 minutes. Easy and simple to op- erate. 99c out of every dollar is profit. $10 to $25 A Day In Your Own Cash Business Start in spare time and you will soon have a fine paying, permanent business. Woodmancy made $25 to $30 a day. There are hundreds of lawn mowers in your neighborhood that need sharpening. You can get this business and make good money. Write for complete information. Mail Cou upon Now! 1 Foley Manufacturing Co. : : 1441 Foley Bldg., 11 Main St..N.E., Minneapolis, Minn. Tell me how T can start my own cash business and 5 make big profits with the Foley Electrakeen Lawn Jj = Mower Sharpener. 2 4 i SPST rerrrrerrre rs. t ‘ 1 SE ae es ee ; 4 : City & ' PS eee a at Home Make up NOW for that education you missed and get your High chool Certifi- cate. These 15 amazing ‘“Ques- tion and Answer” books will pre- pare you for big- ger pay, business and social suc- cess. This new method teaches every High School subject you ought to know: Correct h, American Government, > Soopraphy. Ancient and Modern History, Literature, Spell rammar, Plant and Animal Life, Science, Latin, Physics» Physiography, Civics, Economics. It’s Fun to Learn this easy inexpensive way—now used in 12,000 High Schools. All you do is read the fascinating questions and answers in your spare time at home. A few min- utes and afew cents a day will bring you rich rewards. Increase your earning power; improve your social * qualify for your High School Certificate. 152 after FREE Examination outs a million dollar high school in your home on trial. Send no money—pay nothing on delivery. Oe. the books 5 days absolutely without cost. fail them back at our expense if you aren’t delighted. il thee Ta 4t lo unt ror 'y low . q noomt ~ in ~ after aa making Toca ey pathisotes to be true? Sepizcerneme Sea OW for tion No obligation High kent Home-Study Bureau, Inc. Dpt. 3396, 31 Union Square, New York,N.Y¥_ POPULAR SCIENCE MONTHLY Nearest to Flying Like a Bird (Continued from page 40) spirals which he was making in his descent. Such columns of air, sufficiently strong to hold aloft a heavy, motored plane, would carry a soaring ship high into the air. Along the Pacific, near Point Loma, Bowlus has run into upcurrents so strong that his machine was carried nearly 500 feet straight up. But probably the strongest rising column of air so far reported was met in the Himalaya Moun- tains of Asia by William Beebe, famous ex- plorer of the New York Zoological Society. The wind was blowing up the sheer face of a cliff. At the top, he leaned out over the chasm and was supported by the rising blast. “I leaned upon the wind,” he writes in his vol- ume, Pheasant Jungies, “as I might stretch out upon a rock.” ILE such strong updrafts are uncom- mon, the rising air currents formed by hills and dunes facing the prevailing winds are sufficient for soaring flights. At Rossitten, Germany, where the longest motorless flights have been made and where a famous gliding school is located, a half-moon of sand dunes, ranging in height from 150 to 180 feet, extends out into the Baltic Sea. The prevailing winds blow into this half-moon, strike the steep sides of the dunes, and turning upward, form the rising currents that hold aloft the sailplanes. Here pilots cut figure eights, swooping in long curves over the sea and shore for hours at a time. The other famous German soaring place is in the Rhoen Mountains. The highest peak, about 2,000 feet, is the Wasserkuppe, meaning “water top,” a name given the mountain because of the wet, clinging clouds that fre- quently hang about its summit. From the sides of this mountain, the soaring planes are launched by means of heavy rubber cables which shoot them out into the rising air cur- rents blowing up the mountain side. A few months ago, one soaring pilot had an unusual experience above this peak. He had climbed to an altitude of nearly a thousand feet when he saw a brownish cloud ahead. As he approached, the cloud dissolved into myriad brilliant-hued butterflies fluttering about in the warm sunshine above the mountains. N SUMMER days, the German pilots often engage in the most thrilling of all soaring feats, ‘cloud flying.” By “hitching” their light machines to clouds they travel for long distances over relatively level country. Under every cumulus cloud in a summer sky there is a strong rising column of air. By taking off from a hill and soaring under such a cloud, the sailplane pilot is carried aloft. Practically all of the long-distance flights that have been made in motorless machines have been ac- complished by combining cloud flying with the use of updrafts from hillsides. The most famous “cloud flyer” in Germany is Max Kegel. During the last Rhoen meeting he took off in such stormy weather that two other pilots were forced to land. Driving right up to the front of an immense cloud, he clung to it and was sucked up out of sight. Battling the violent cross currents in the dense mass of turbulent fog foam, he allowed himself to be carried by the cloud’s upwash to nearly 4,000 feet. Here he headed away from the cloud and soared for nearly forty miles. Kegel built his own ’machine, as did another soaring star of Germany, Gottlieb Espenlaub, a carpenter’s apprentice in a village near the Wasserkuppe. Espenlaub watched the ma- chines at the annual Rhoen competition and one winter built one of his own in a barn back of his mother’s house. That year, his flights were among the outstanding events of the Rhoen meet. He was the first glider pilot to “make a flight towed (Continued on page 153) May, 1930 a year. —— _— oo im- mediately adopted this simple crimped tin cap. This invention would have made you independently wealthy. Fortunes await inventors working along right lines. Concentrate on things that are NEEL ED. Get Raymond Yates’ new k. **1000 NEEDED INVENTIONS” Costs only $1.50 and may lead to a big idea. Find out what industry needs and the public wants, That’s where the money is! Mr. Yates’ book tells you what these things are. Send no money. Just write postal. Pay mail man $1.50 plus postage when book arrives. Your money back if you want it, This offer limited. one now and get on the right track. (Outside U. S. $1.70 cash with order.) BUREAU OF ‘INVENTIVE SCIENCE 25 Wisner Building, Rochester, N. Y. TRADE-MARKS DO NOT LOSE YOUR RIGHTS TO PATENT PROTECTION Before disclosing your invention to anyone send for lank form “Evi- DENCE OF CoNcEPTION”’ to be signed and witnessed. LANCASTER, ALLWINE & ROMMEL Registered Patent Attorneys 274 Ouray Bidg., Washington, D.C. Originators of forms ‘Evidence of Conception” Underwood, Remington, al—also portables —prices fi smashed to oo half. (Easy terms) 4 SEND NO MONEY! All late models completely rebuilt and refinished brand — Guaranteed a ten years Send no mo catalog shows actual machines in full colors. Get our direct-to-you easy pay- > © — plan phe 10 day free trial ae Amazing ~ values—send at once. 231 w. international Typewriter Exch., Dept. 5: UNPATENTED IDEAS CAN BE SOLD I tell you how and help you make the sale. Free particulars. (Copyrighted) Write W. T. Greene, 921 Barrister Bldg., Washington, D.C. INVENTORS We have been in business 30 years. If your inver.tion or patent has merit, send details or model, or write for information. Complete facilities. References. ADAM FISHER MFG. CO., 183-D Enright St. Louis, Mo. PATENTS Trade-marks, Copyrights, Patent Litigation, Handbook with illustrations, 100 mechanical movements. Sent free on request. ALBERT E. DIETERICH Format member Ezamining Corp. U. S. Patent Office Register ene p awyer and S years’ experience 681-A Ouray Bldg. Washington, D. C. PATENTS BOOKLET FREE 5 ae PROMPTNESS ASSURED Send drawing or model for mh. and advice WATSON E. COLEMAN, Patent Lawyer 724 Ninth Street "Washington, D. DC.

Page 155

May, 1930 POPULAR SCIENCE MONTHLY 153 Nearest to Flying Like a Bird TRADE-MARKS simple (Continued from page 152) a ae lon . ° ’ d behind an airplane. The danger of being ’ aloe’ towed in a motorless machine behind an air- ote)“ 4 R IG H TS NEED- plane or an automobile is so great that it should be attempted only by a seasoned pilot. ‘ Of the few serious accidents that have occurred OUR OFFE - FOR THE PROTECTION m.. in flying gliders in the United States, most . OF YOUR INVENTION k tells have resulted from inexperienced pilots at- . oc tempting towed fight. YOUR FIRST STEP—The inventor rant ft While eee —- a few minutes fnstene- should write for our blank form e right tion can make a hop in a primary training “ on : glider, the handling of a soaring ship demands riage O F INVENTION. Y. skill that only careful instruction will give. At Before disclosing your invention, a the Rossitten school in Germany, nearly fifty students a month are trained in handling various motorless machines. The cost there is seventy-five dollars for tuition and sixty cents a day for food. The only soaring schools sketch and description should be made on our “Record of Invention Blank,” signed, witnessed, then re- turned to us and we will place it in in America are located at Cape Cod, Mass., our fireproof secret files. We will also where is Rees een Sens pnd "| give our opinion as to whether the Cook vee San Diego, Calif, where W. H. Le FP WW de> Bi invention Comes within the Patent Bowlus teaches pupils to pilot his soaring planes. PE ERS Office definition of a patentable In~ vention. This “Record of Invention” will serve as “proof of conception” until the case can be filed in the Patent Office. There is no charge or obligation for this service. Write for Our Five Books Mailed Free to Inventors Our Illustrated Guide Book HOW TO OBTAIN A PATENT Contains full instructions cy ee U. S. Patents. Our Methods, Terms, and 100 Mechanical Movements illustrated and described. OUR TRADE-MARK BOOK Shows value and necessity of Trade-Mark Protection. Informa- tion regarding TRADE-MARKS AND UNFAIR COMPETI- TION IN TRADE. OUR FOREIGN BOOK We have Direct Agencies in Foreign Countries, and secure Foreign Patents in shortest time and at lowest cost. PROGRESS OF INVENTION Description of World’s Most Desirable Inventions and Pressing Problems by Leading Scientists and INVENTORS. DELAYS ARE DANGEROUS IN PATENT MATTERS TO AVOID DELAY: YOU SHOULD HAVE YOUR CASE MADE HE history of motorless flying falls into two groups. First, the gliding pioneers—Mont- gomery, Lilienthal, Chanute, and Pilcher— made the experiments that led to the Wright brothers. They jumped off hilltops and main- tained balance by swinging their legs from side to side. After the airplane had demonstrated its power in peace and war, machines without motors, but with regular controls operated by pilots in streamlined cockpits, made their ap- pearance in Germany. In 1920, the first soaring meet was held in the Rhoen Mountains and the record made by Orville Wright in 1911, when he hovered over the Kitty Hawk sand dunes for ten minutes, was broken. The Era of Soaring thus begun culminated in the fourteen-hour flights of Schulz and Dinort. In England, there has been a recent revival of interest in gliding and soar- ing and new clubs are springing up. In America, Edward S. Evans has offered a $2,000 prize for the first motorless flight of ten hours. , Bowlus has already stayed aloft nine hours AS and no one will be surprised if the ten-hour mark is shortly passed. VICTOR BUILDING Our New Building Noaeip Opposite U. S. Patent Office Specially Erected by Us for Our Own Use AT practical use is soaring? As a thrill- he ing sport, its attractiveness is easily seen. But it is more than a sport. Soaring planes provide aerial laboratories for studying meteor- ological phenomena and for making full sized + ves : : SPECIAL IN OUR OFFICE to save correspondence, secure protection © Mba ey Sed stydng date Patent Gh Te Dhol wad wre ode neem A 4 photograph with a description of your invention together with swirling white flakes flow past the machine, $25.00 on account. We will make an examination of the U. S. Patent seeking new ideas for streamlining the struc- Office records and if it is patentable we will prepare the official drawings ture. The fund of information about the effect immediately and forward them for approval. If the invention is not " of clouds, hills, and nee patentable we will return the fee less the cost of the examination. oe pte ny) pean PAYMENT OF FEES IN INSTALLMENTS write Moreover, flying schools are recognizing the It is not necessary that the total cost pf a patent be paid in one payment. ces. effectiveness of glider piloting as a preparatory We permit our clients to pay for theif applications in three installments course for flying motored ships. The largest as the preparation of the application progresses in our office. 3, Mo. air transport organization in Germany requires ALL COMMUNICATIONS AND DATA STRICTLY SE- its flyers to hold glider licenses before they are CRET and CONFIDENTIAL. INTERFERENCE and IN- accepted as pilots of big passenger machines. F RINGEMENT SUITS PROSECUTED. Our Large, Compre- F Thus not only thrilling, but also valuable, hensive Organization has been established for 3o years and _ offers — is the soaring work of these modern birdmen - oats np er : -_ Personal ony by experienced vi unica . . wyers an raitsmen. es gia Oo have you consuit us or to answer any questions ae eee planes ride on the wings of in deoad to Patents, Trade-marks or Copyrights without charge. 7 ’ We Assist our Clients to Sell Their Patents ‘Om Ment snensine W. Mi Beuten, Renata Highest References—Prompt Service—Reasonable Terms D.C. greatest soaring pilot, tells his own WRITE TODAY a story of his thrilling adventures in FREE VICTOR J. EVANS & CoO. a motorless planes. You will not want COUPON Registered Patent Attorneys: Established 1898 =, to miss this article by the man who MAIN OFFICES: 690 Ninth St., Washington, D. C. > taught Lindbergh to glide. A list of BRANCH OFFICES: 1007 Woolworth Bldg., New York City; 1640-42 Conway Bldg., Chicago, manufacturers of gliders and equip- Ill; 514 Empire Bldg., Pittsburgh, Pa.; £28 Fidelity Phila. Trust Bidg., Philadelphia, Pa.; ces ment that are recommended by the 1010 Hobart Bldg., San Francisco, Calif. LTS National Glider Association will be sent Gentlemen: Please send me FREE OF CHARGE your books as described above. to any reader upon request. Address r The Editor, Popular Science Monthly, : PROMI is.eis 5 bc eieig 0 0d:cb's Be EVERNE «BRERA axes dae oma vo eeetal Ne ae eee et o. 381 Fourth Ave., New York City. ee rer errr errr mm seinen

Page 156

He Kept the Job He Liked —and increased his salary 73% W. A. Day, of Woonsocket, R. 1, wanted more money. But he liked his job—didn’t want to change — made i his mind to get more money right where he was. He enrolled for le home-study train- ing ini Higher Accountancy— followed it with Modern Business Correspondence—is now pursuing LaSalle training in Business Management. “In actual results I have received a salary-increase of exactly 73.3 per cent since the date of my first enrollment,” writes Mr. Day, “but I consider this equal to 100 per cent in the eae, Lay I have earned this increase without cha: ition.” How much is it r hy to you to win substantial advance- ment—within a comparatively few months?The way isclearly outlined in a fascinating book, ‘‘Ten Years’ ion in One.” The compan wi will Iibring it to you FREE, together with Sesites gold wel meet apttsa te es cea seks os eo righter future, clip and “ i the esupen NOW. - — —— ——Find Yourself Thru LaSalle!—— —— — LASALLE EXTENSION UNIVERSITY The World's Largest Business Training Institution Dept. 583-R Chicago Gentlemen: Send without obligation to me infor- mation regarding course indicated below: OB OCommercial Law OModern aero ceneree O Modern Business Corre- O#igher Accountancy spondence OTraffic Management OExpert Bookkeeping ORailway —— os Oc. P. A. Coaching OBusiness English Oo Degree of mam of LL.B. OCommercial Spanish O Modern Foremanship OPersonnel Management UEffective Speaking Olndustrial Management OStenotypy—Stenography OBanking and Finance OTelegraphy OCredit and Collection Correspondence Address 34 Lesson Drawing Course $9.98 The b egest vi value ae. ever saw he rtised ere .. Haven't aa often ket ae — you could draw cartoons, illustrate some idea, sketch some pretty face, etc.? You can do all of thesethings. One of America’s most fa- mous Cartoonists and illustrators has developed a great, simple system for success in all branches of Commer- elal Art. This system has revolu- a. the entire theory of draw- illustrations, within reach of every one. If you will devote a few hours each week to the Course WE ABSOLUTELY GUAR- ANTEE that you will learn to draw and = well before you have half finished the to make this oo good we a) refund every cent paid us. elimi- nating pase office force - unee ce, expensive cata’ etc., enabled t to > make &@ price or 2.98, the cheapest price ever = fora high- grade home study cou earn to draw. Itisa bi asset, “no matter what field you are in. Send No Money Just order the Course, and on arrival = postman “ erasers, thumb nd De in full’ tee the ‘ent tire Co teake ete., enabling you plus a few cen urse Yrawing Outfit. not entirely to go to work without nal cost. ve will REFUND MONEY. LEDERER SCHOOL OF DRAWING, Dept. 524-0, Chattanooga, Tenn, Orders! rom outside the U. 8. A.are payable $3.28 cash with order. FHEWORLD WITH SCIENCE ACH week Science News- Letter gives you authentic, highly interesting news of every branch of science. It brings to its readers scientific news in a concise under- standable style. You'll find it stimulating. Science News-Letter $1 for 13 Weeks Introductory ae for 6 Months 2181 B St., N. W ashington, D. C. If you order the Course at once, we will include a drawing outfit, consisting dl artist's pencils, pens, POPULAR SCIENCE MONTHLY Oil Makes the World Go Round (Continued from page 28) fight against friction is a bearing which lubri- cates itself. It is produced by placing graphite in a vacuum to extract the air and then forcing in molten babbitt or —— under tremendous pressure, sometimes reaching a million pounds. While bearings of only moderate size can be made of this “alloy” of graphite and metal, they are expected to prove valuable in textile factories where oils ruin the fabrics. The properties of the alloy are similar to the famous self-oiling lignum-vitae wood, used for propeller shaft bearings on steamships. On the Leviathan, for instance, each stern tube carries two bearings of this unique wood, one seven feet long and the other ten feet long. Many of the early American clocks had lignum-vitae bearings. Some ran for a hundred years with- out oiling. HERE is no known lubricant suitable for all purposes. Each machine has its peculiar requirements. A drop of airplane oil would stop a watch. Watch oil would be useless in an airplane motor. -As many as twelve different | kinds of lubricants are made by one manufac- turer for use in automobiles. Only recently has intensive study been made of the nature of lubricants and the effect of wear upon them. One of these tests answered the old question: Does oil wear out? The answer is: No. What does happen, it revealed, is that the oil loses its lubricating properties through the absorption of moisture, dirt, and oxygen. It is known that when oil absorbs oxygen, a compound is formed that dissolves temporarily. But when the oil strikes a cold surface, it separates as a solid material, often clogging pipes. While laboratory tests do not determine just how a lubricant will act under actual road con- ditions, they have shown that all satisfactory oils have several qualities in common. They have enough viscosity, or body, to hold the metal suriaces apart. They have enough fluidity, or ability to flow, to enter into all the spaces of the bearing. They have cohesiveness so they not only adhere to the metal surfaces but the particles cling to each other so that films may be formed and maintained. They have a capacity to carry away heat and keep the bearings cool. They have low solidification temperature and high evaporation tempera- ture. When exposed to the air, they do not dry | workers carry on their experiments. out or become gummy. They do not have un- due acidity or a tendency to corrode metal. It is in search of these qualities that laboratory The oils obtained from petroleum most nearly meet all | these conditions. ECENT figures show that when a “hot box” occurs on a freight car, the railroad has to haul a ton of freight 2,254 miles, prac- tically from coast to coast, to cover the cost of dropping off, repairing, and picking up the car. In American factories, from ten to fifty per- cent of all power is lost through ineffective lu- brication. Cutting down this waste in power is the aim of lubricating research. OWN through the fertile valley where the Mississippi flows to the Gulf, thousands of men are toiling at this moment. They are building levees and dikes to tame Ol’ Man River, against the time when he next will be in flood. Will they succeed? In a com- ing issue of POPULAR SCIENCE MONTHLY, a high Army official, one of the leaders in the work, will "explain just what Mississippi flood control means and how engineers are tackling one of the biggest engineering jobs since the building of the Panama Canal. = Only 4 Motions used in instrument. Our native teach you to master them quickly. Pictures Everything explained clearly. show how. Playin Half Hour little practice. No pane = musical needed, GIVEN when you enroll —a sweet toned HAWAIIAN GUITAR WRITE AT ONCE for attrac- tive offer and easy terms. postcard will do. ACT! Easy Lessons Even %e you don’t know one note from another, the 52 printed léssons and clear pictures make iteasyto learnquick- ly, Pay as you play. 9th Floor, W: NSB | Ban other courses. The same thorough instruction on Tenor (SANSS ie, Violin, Tini Tiple, Tenor Guitar, Ukulele, Banjo Ukulele. ‘Well-known instructors. Write for FIRST emenaame N CONSERVATORY. of MUSIC, Inc. Bidg., Dept.2 46, Agreed asa (eeanett ce School Under the Laws of the State of New York—Member National Home Study Council, laying this fascinating awaiian Instructors ying Value $18 to $20 No extras-everything included information. New York, N. Y. F R E Ease — today for FREE illustrated 48-page book, givi ng dotaite how you can be = oy ed 7 eek a re ene entjon age. Be a py 77 Extension Division SCHOOL °F ENGINEERIN — Electricity | This NEW Practical W Patented new Unit Boerd &: Se tem brings full-sized Electrical ht into your home! Learn Electricity by equipment rig doing at home No obliga- ed Man Mea. Niiwauke vision of engineers of this oe. Trained $5000—$10,000 a year. Start now! under super- men earn G e mets what N.P. given in our to $100 a week and — -4— WANTED 1000 Trained , the pn make, So can jentifie j= Lm he | of 8c ic w uick he know POULTRY INSTITUTE WASHINGTON, D.C. a ACTS, te o charge Get Into A Business of Your Own - EARN ‘150 to $300 Monthly ad Start BIG PROFIT MAKING BUSINESS of your own, “8 Hour Battery Charging —_ and practically NO INVESTMENT. Anyone ully operate. Every car owner a customer. 20° aaa Car Washing. Electrical Service, Spray pao and Are Welding offer same opportunity. B equipment will pay foritself on EASY MONTH- LY PAY MENT PLAN and with a handsome pro‘it for you. Write now for details, stating what you're interested in, to Hobart sros., Box 1 OV, Troy, Uhio. Requires sinall 30 DAYS TRIAL-Pay Out of Income Terms BE A MOTION PICTURE Bin t Make big money his —— = Dleasant w demand for ye Operators. MOTION PICTURE OPERATORS SCHOOL 59 Sproat St. OPERATOR ee LEARN TALKING EQUIPMENT Detroit, Mich Learn Cartooning mous Picture Charthte The: demons Piet ure Cc ‘artMethod of teaching original opened the door of s: ccess for hun- dreds of beginners. Whether you think you have talent cr not, send for sa a. chart to test your abil- examples of the work of po te ~ 5 ae THE EI LANDON $ SCHOOL ity, an 1451 National Bldg. DEPT. 591-K Men and Women— Industry’s leader offers you direct- to-wearer agency. Pays bi work. Thousands successful. outfit free. Start at once. Write today. TON MILLS, 79 Fifth Ave.,hew York, N.Y. drawing has Cieveland, uv. + - Happy Sample INC. A definite program for getting ahead financially will be found on page four of this issue.

Page 157

—_

-@rsSe:S “S yy aor esa 8 —

, ate aaa <s mr * i! FS ir

May, 1930

Circuits That Improve Tuning (Continued from page 71) is shown in Fig. 2. By a careful adjustment of the magnetic coupling between stages, the desired band pass effect can be obtained, and in any event such a circuit materially improves the tuning. Of course, it does not add any- thing to the signal strength. In fact, it de- tracts from it somewhat and should only be used with a radio-frequency amplifier circuit that is in itself extremely powerful if distant stations must be received. In many ways this circuit resembles the diagram of an ordinary five-tube radio receiver where two tubes are used as radio-frequency amplifiers. Coils C and E, however, instead of being in the plate circuit of a tube, are con- nected in series with coils B and D. The experimenter who wishes to test out a circuit of this type will find a three-inch coil form convenient. Coil A should consist of ten turns of wire wound right over coil B, which for a .00035 mfd. condenser should have sixty turns. Coils C and E should have four turns each,and the electromagnetic coupling can be regulated by placing the coils directly at the ends of coils D and F and then adjusting the spacing. Coils D and F, of course, should have the same number of turns as coil B if similar condensers are used. With .0005 mfd. condensers, coils B, D, and F should have fifty turns of wire. HE dotted lines indicate shielding, and it is extremely important that the units be shielded as indicated. Of course, it is hardly to be expected that a home built pre-selector cir- cuit of this type will equal in efficiency a care- fully engineered and factory built job. If the three condensers are ganged or oper- ated by a single shaft it is desirable to use tiny synchronizing condensers so that they can be got into step. This will make up for slight irregularities i in winding the coils. In fact, the adjustment is so critical that even the ‘best factory built selector circuits use them. The circuit shown in Fig. 1 uses electro- magnetic coupling, and on the lower fre- quencies which represent the longer wave lengths near the high numbers on the dials, the band pass effect decreases and the tuning be- comes extremely sharp. On the high fre- quencies, which represent the shorter wave lengths near the lower numbers on the dial, the band pass effect broadens out materially and the loss in signal strength also is much less than on the other end of the dial. IGURE 3 represents another form of band selector circuit where capacity coupling is used instead of electromagnetic coupling. It is a simple circuit, easily built at home; and al- though there is some loss in signal strength, it will be found useful on a receiver that has a tendency toward broad tuning. Band pass characteristics also are excellent. Coils H and K are alike and should have sixty turns of wire for .00035 mfd. tuning condensers. Coil G should have ten turns of wire; assuming, of course, that three-inch coil forms are used. Shielding also has to be carried out carefully and trimming condensers should be used across each of the tuning condensers in the two-gang unit. Condenser X should have a capacity of .02 mfd. « While, as already mentioned, pre-tuning cir- cuits of all types cut down the signal strength, the loss is not so severe as to prevent the use of such a circuit for improving the reception results when it happens that a number of local | Stations are so powerful that they interfere | with each other. It is possible to use either one of the selector circuits shown with one tuned stage of screen grid radio-frequency amplification, a detector tube, and two audio | Stages in a circuit that will outclass the usual four-tube set for local reception.

POPULAR SCIENCE MONTHLY THIS MAN SS MAKING SHARPENING LAWNMOWERS IN SPARE TIME WITH THE “IDEAL” LAWNMOWER SHARPENER You've Man, Why Don’t You Do That? ¢.: the deenee-—tho same chance as W. T. Moore, Twin Falls, Idaho, who made $1200 net profits in 90 days—the same chance as Walter Wever, Middletown, N. Y., who made $1000 in 4 months—the same chance as hundreds of others who have reaped rich rewards with this efficient lawn- mower sharpener. If you work at Use Your Spare Time. a trade, put an Ideal in your basement and earn I to $6 an hour evenings and Saturday afternoons. E. McCormick, Saginaw, Mich., writes: “Five years ago Y bought an Ideal Shar ener on which I have ground over 5,000 lawnmowers. In the last few weeks I worked at my trade, machinist, full time 9 hours a day. I also ground 97 mowers which netted me $114.10 clear gain.” You Make Money Right Away. fcsriey. Stillwater, Minn., writes: ‘‘We set the machine up 2 weeks ago Friday; since that time have sharpened 102 mowers.’ at’s close to $200 in Kearney’s pocket for 2 weeks, work! Our Free Book Tells You How ‘°°, 2" others have made themselves independent—bullt substantial = permanent BIG PAYING businesses with this Ideal \ Grinder. Send for this book today—lIt’s free. SIGN THIS AND MAIL TODAY THE FATE-ROOT-HEATH CO. 933-956 Bell St., Plymouth, Ohio, U.S.A. { Send me the book that tells me how . can make my {

6 93 The “‘Ideal’’? Lawnmower is a wonderfully simple Sha rpener machine that sharpens all makes of mowers perfectly, Cs my without taking the mowers apart. = up the mower, set it in the ‘ i make a few simple adjustments and proceed to sharpen. In 15 minutes the mower is ready for the lawn, and you have made $1.50 to $2. 00—dependin _— the charge you fix. No training requir and machine set up in a few minutes. Plug into light socket and start to sharpen. Hundreds of dull mowers in your locality fi. nnr pened. Owners are looking for Py place to get them sharpened. No town too small. Newcomer, Vinton, Ia., writes: “*People come from males around and other towns r+ get their mowers ground.” The “‘Ideal"’ earns money the year round, too. Sharpens skates— kinds—perfectly. Cc. S. Coburn, Little Rock, Ark., "ics. st, earned eneueh in_ 18! months to for itself and $1857 worth of a itional machinery.

spare time worth $4 to $6 per hour { MI ince oiite bp +4405 dene 55s dee’ sagen eee eee { SD 2 << sche. Peiats whee dans nes abe tae Ws Eee f TN ai. 6. 0 6 Bie «nena emo peniacs ee f

TO THE MAN WITH AN IDEA Learn in Los FATENTS Procured. Trade-Marks Registered. —A comprehensive, experienced, ab of you service oO! for the. Diotestion and develo — our ideas. Be an electrical specialist. Gain quick success in this most- Preliminary advice gladly " without fascinating charge. Booklet of f «By = A... for and profitable field. Se tremendous electrical projects costing more than $100,000,000.00 —unlimited opportunities now. Practical, intensive training by National’s job-experience method in 6 to 9 months. All —— essentials included. School endorsed in lustry. You learn all branches of electricity; radio. Million dollar f institution; all modern disclosing idea free on request. IRVING L. McCATHRAN PATENT LAWYER Formerly with and successor to

uipment and training facilities. Life chard B. Owen scholarship. ‘No age lim. Free employ by i REE 705 International Bldg., Washington, D.C. ment service. Over 20,000 successful 41-D, Park Row, New York City

graduates. 25th year. illustrated BOOK 84-page catalog sent FREE. Write today. Dent 308-ED. 4006 So. tigueroa, Los Angeles, Calif. ERED ATENTS SECURED TRADE-MARKS REGISTERED -class professional service for Inventors and Trade-Mark Users is necessary for PROPER PROTECTION. We Offer you our facilities on Reasonable Terms. If you have an invention send us & model or sketch and description and we will give you our OPINION whether your invention comes within the provisions of the Patent Laws. Our book, “HOW TO GET YOUR PATENT” and Record of este: Certificate sent on request. DELAYS are DANGEROUS in Patent Matters. E ASSIST OUR CLIENTS TO SELL THEIR PATENTS TERMS REASONABLE BEST REFERENCES ence ncosaens WRITE TODAY amen enesenesots RANDOLPH & COMPANY, Patent Attorneys Dept. 130 Washington, D. C. TRADE -MARKHS

REGIST

I i a aes. 6: 5.0:t6s0 soe 40:8 wide SEU eo Pwo es Ulnwi dia aes eases idan ee lean ees ee ee ' a ee |

Page 158

156 POPULAR SCIENCE MONTHLY May, 1930

——_—_____, Plans a Diagrams *@ Directions Death Masks Solve Crimes (Continued from page 26) for Wonderful New Things to Make in your HOME WORK- SHOP The most modern, most complete, and in every way the most practical Manual now available for the man who likes to make things with tools. - - _ _— | Brand New Just Published The scope of The Home Workshop Manual is really amazing. It is hard to believe that such a great variety of things to make can be covered

735 Illustrations Once you have seen these wonderful photos anddiagrams, and have worked out for yourself some of these plans, you will readily admit

A negacoll cast of this safe door was made in order to preserve the robbers’ fingerprints. in such complete de- that it is the most that, when inked, they give accurate finger- tail until you actually helpful tool in your prints. Models of birds made with negacoll see the book and look whole kit and that it ]} show the veining of each feather. Another advantage of this substance is that its elas- ticity permits the making of a hand and wrist to you. | as one unit, instead of in two parts. This, too, holds good in the case of the ears and other parts of the body. To fashion a negacoll “sculpture” of the head of a living person, the operator seats his subject before a mirror. Like a barber giving a | THE HOME WORKSHOP | massage, he kneads with his fingers the nega- coll, which has been cooked for half an hour | | and then allowed to cool to a lukewarm tem- | | perature. The thick, molasseslike but non- viscous material is applied in a half-inch layer. The operator begins under the chin and works upwards. In fifteen minutes the negacoll has hardened and the mask is lifted off in one will be worth many, |) many times its cost through its sixteen big sections.

It gives you clear, complete, and simple directions for doing expertly all those jobs of craftsmanship you've often thought of doing, and suggests scorcs of others you can easily do with the proper directions. Put this handbook in your — $$. tool chest for quick reference—follow its plans and directions every time you piece. have a job to do with tools. Whether you are interested in woodworking, in The back of the head is reproduced in a metal work,-in ship and airplane model making, in radio building and clectrical similar manner, while the ears are molded work, in sporting equipment, in painting and decorating—or in all of thern— | | separately and later fitted into the two-piece you will find an expert of high standing in each ficld ready to guide you with cast. So elastic is negacoll that the ear molds instructions you can readily understand. are pulled off like miniature gloves. A broad- mouthed syringe is used to spread the sub- stance on the top of the head. This is done in order not to disturb the hair, which is only

The Sixteen Sections of The Manual slightly flattened when the hardened mold is a lifted. Are Graphically Illustrated P y COMPLETE cast of a hand is made by 1. Building Fine Furniture | by Hand 2 Model Making = thrusting it into a pot of melted negacoll 2. Furniture of Modern Design » Radio and Electrical Projects and letting the substance harden about the 3. How to Use Small Woodwork ; ° & : ————<— ” ——— a hand. By withdrawing the hand carefully, a | 4. Repairing | old Furniture 12. Boats and Sports _ | mold is left ready to be filled. For a cast of the | 6. Noveltice—Ornamencal and 14 Oeaeedian eek back of the hand, the negacoll is kneaded over Amusing mit 15. Equipment to Make for Your the hand as it lies on a table and lifted off in | 7. Woodturning Simplified Home Shop one piece when hardened. When the Viennese @, Dusesptive Stnaet Ween 16. Better Home Workshop Methods strangler was arrested, Dr. Poller fashioned striking casts of both the backs and palms of : . . his hands. | We Will Deliver It Immediately _To produce the positive, the mold is filled f, FRE . either with plaster of Paris or with a new sub- | ---lOr E Examination stance called “hominit,” also an invention of Soe : | | Dr. Poller, which is made in various colors. While it is the finest work of its kind eve gm nena ---- | ° ° ceaiaaen ter one gellichar, ibe peten te amis | ORDER ON THIS COUPON | | The negacoll molds can be used again or melted

’ P , } $5.00. No such investment that you have ever | 3si Fourth Avenue, New York Nv 7. ecules to make new casts. aa grag ue Plenwure, and satis; | Fleasesend mea copy of THEHOME WonxsHor || | Negacoll has proved useful for other pur ‘ ] MA? or free examination. thin ten days ; 3 ivi your ownership and use of this manual. And j of receipt I may return the volume, if I wish, and poses besides the making of masks of the living you need not pay a penny for it until after you owe Rothing: It I keep it I will remit $5.00 within and the dead. Not long ago, a burglary was have gone thoroughly through its profusely - eth wetness committed in a Vienna store, but the thieves illustrated pages. You need send no money | . : . d NOW—the manual will come for FREE a a were surprised while trying to crack a safe an Examination. And if you decide that you do | | | fled. The potice called in Dr. Poller, who not need it, simply return it and you owe 4 Address ..............-.-..- 2. 20s es esses seen | | made a negacoll “sculpture” of the safe door, nothing. Otherwise remit $5.00 and retain ° ° ° the manual. Re ee TOD ncn sattionnees showing accurate fingerprint reproductions. ! To catch the crooks took only a few days.

Page 159

1930 rer- coll her las- rist her the his ga ga- our m- on- rer. rks nas yne la led ece lds id- 1b- in ily is oll er ir- ng id ho rr, May, 1930 Stunt Flying (Continued from page 59) cloud. I couldn’t be sure whether I was upside down or right side up. But I wasn’t worried. The worst that could happen would be to come out of the cloud in a dive, upside down or in a tail spin. And stunting had taught me to recover from any of these. On a cross-country flight, I was once flipped completely over by a violent air current dur- ing a storm. Upside-down flying prepares a pilot for a surprise like that. I usually go into an upside-down glide by pushing the stick forward at the top of a loop. This holds the plane on its back. Another method is to make a half roll, coming out in an inverted glide. In upside down flying, the rudder oper- ates as usual but the elevator and ailerons work opposite to the manner in which they ordinarily function. To come out of an in- verted glide, I pull the stick back as quickly as possible without jerking it. This brings the ship out as though emerging from a loop. The commonest error students make in upside- down flying is pulling back the stick too slowly at the end of the glide. This allows the ship to gain excess speed rapidly and to make a wide arc before it can be leveled off. HE most spectacular stunt of all is the Immelmann turn. It is a half roll at the top of a loop. The ship zooms up and over on its back. Then it rolls over ‘“‘on its feet” and flies away in the direction opposite to that in which it entered the maneuver. Great excess speed is required and the strain on the plane is such that the stunt should be attempted only with high powered, specially braced ships. Another method of making a sudden right- about in the air is the wingover. This is a quick climbing turn followed by a diving turn. As I zoom upward, I bank and turn the plane. At the peak of the climb the bank is at its steepest and the turn at its sharpest. On the down glide, I gradually decrease both bank and turn so that the ship straightens out and ends in level flight. I have a particular affection for the wingover. And with reason. A little over a year ago, I was bringing a Stearman plane east from St. Louis. Over Illinois, fog closed in. It drove me lower and lower. As I approached the Indiana line, I was hedgehopping at ninety miles an hour, looking for a landing field. Near Terre Haute, a huge house loomed out of the mist dead ahead. I pulled back the stick and shot up in a high wingover. It carried me into blinding fog. But I knew the maneuver would bring the Stearman around in a 180-degree turn. It would point me back in the direction I had come, over territory with which I was familiar. When I sat down in a near-by hayfield, I found that if I had zoomed up into the fog over the house and then come down straight ahead, I should have crashed into a group of high barns and silos half hidden in the mist. HE split-S turn differs from the wingover in that the ship is stalled at the peak of its climb. I perform a fast split-S by pulling back the stick sharply and simultaneously applying fuil rudder. The ship climbs, stalls abruptly, falls off, and emerges from the dive headed in the opposite direction from which it started. In coming out of a split-S or a loop or a falling leaf maneuver, the ship is headed downward at a steep angle. But it is traveling below flying speed. It must dive for a second or two with elevators neutral. A common mistake by students is pulling the stick back imme- diately upon coming out of these maneuvers. A tail spin usually results. To get out of a spin, a pilot throttles the motor, pushes ahead the stick, and applies rudder opposite the di- rection of the spin. One of the greatest stunt flyers I remember was the Frenchman, Georges Lagagneux. In 1912, he invented his hair-raising “ tail-slide,” wi th which he (Continued on page 158) POPULAR SCIENCE MONTHLY LEARN gprs 157 Don’t spend your life waiting for $5 ’ raises in a dull, hopeless job. Now... « and forever ... say good-bye to 25 and 35 dollars a week. Let me teach you how to prepare for positions that lead to $50, $60 and on up to $200 a week in Electricity. Learn Without Books or ror in 90 Days In the Great Coyne § Lack of experience — age or advanced education bars noone. I don’t care if you don’t know an armature from anair brake —. don’t expect you to. The secret of yne ae” that it is ALL PRAC- TUAL WORK. No books—no les- sons—YOU LEARN BY DOING on REAL ELECTRICAL MACHINERY. Everything from doorbellsto power plants with instructors at your side at all times. YoucanEarnwhile too If you’re short of money my 5 ~ ment Depernnent will help you FIND PART TIME WORK, and whenyou grad- uate they will help you get that Big Pay Electrical Job. I’ve done all this for thou- sands of others—I’11 do the same for you. Aviation, Radio and Auto- mobile Electricity Now Right now I’m including my big new Avi- ation Electricity, Radio and Automobile Electricity course at no extra cost. COYNE ©": Electrical SCHOOL C. Lewis, Pres. Est. 1899 S00 S. Paulina — “Dept. 60-73 Chicago, lil. —————— hops GET THE FACTS Coyne is your one great chance to get into Electricity. Every obstacle is re- — This school is 80 years old— yne training is tested— proven beyond on Qt ee orsed by many large elec- pone eee. Youcan find out {> absolutely free. Sim- pt mail the coupon and let me send you big, free book of 150 photographs eee facts.,. jobs... CB oe opportunities. This does notobligate you. Soactat once, Just mail coupon, GET THIS FREE BOOK i ad H.C. LEWIS, President | YNE ELECTRICAL SCHOOL, Dept. 50-73 500 S. Paulina St., Chicago, fll. Please send me your Free, Illustrated Book i on Electricity poe oe Coyne. No obligation. Give | details of special offer too. ACC Feecstive ti tants and C. r4 ecu up Ageoant seein tae Gulted Dantes. bem, Gals for C.P.A. examinations or executive Witiam B. Castenholz, A. M., G. P..A., i: including members of the American I rite ree kk, “A ; ew Bungalow Business Earns =1h¢ MONEY’ Everybody buys Popcorn, Or- ange Drink, Coneys, Peanuts, Ice Cream—All are Long Biggest, Most Attractive Little Store in America. Pays as } Much as 80c Profit on Every fd, Dollar you take in. Wool- (eae worth does it with Dimes. You ; Can Too! writes, “I § took in $338.20 in 3 Days.” Laubach reports as much as 300 a week, Bailey takes in around $140 a week. Excel- ; Sr lent Locations Are Open | j Everywhere. ; Small Capital Starts You! 4, Rest, opror. fanity own a cash business, be your own boss, with Big Pay. Buy on our Easy Payment Plan. Wall reposts his machine pa | iy j Ad. for en in 30 days. Big Opportunity or in Write for FREE CATALOG in Colors Tells All about Big Profits being made with the Bun Also shows 14 “other models for theaters, drug stores, oy etc. Write oday for Your Free Copy! NATIONAL SALES & MFG. CO. 637 Keo, Des Moines, lowa Is there a Job and a Fature for Me in Awi ATION ? "THERE'S a better job and future for YOU in Aviation than in any other industry because Aviation is just be- ginning its period of BIG GROWTH! During the next few vears Aviation is going to pick its leaders and Walter Hinton —first to pilot » pla.e across the i [ Atlantic, first in other deeds of a at om | YOU the air, and ay a recognized —by looking and acling leader in the Industry, is the first ahead—can be one of world-famous aviator to offer you them: the training and backing you need Compe Aviedten °f Give Hinton just a part mmercial Aviation. ive riinton just a par Get FREE Book A Perhape the season Hinton je not of your spare time dur- ciate what a tremendous oppor- tunity Aviation offers you. that are inal to YOUR FUTURE. Mail the coupon now. ing the next few months and he'll give you the kind of training that employers are paying real cash to get. He will even help you get a job through the free assistance of his Employment Depart- ment. MAIL NOW ! 4 e Walter Hinton, ym vig | 302-G 3 Aviation Institute of U. S. A. 1 : Lane | a trAvenuie, j Washington, D copy of “Wings of { “opportunity. ae it like to know what kind of « future Commercial ers M r i Send my FREE cop ' ! t 1

Page 160

158 POPULAR SCIENCE MONTHLY PLASTIC WOOD IS WOOD Reg. U. S. Pat. Off. |e handles like putty, white lead, or any other plastic filler, but it hardens into solid wood, with all the natural proper- ties of wood except the grain. When hard it will not crumble or disintegrate, can be worked with any tools, and takes paint, varnish and lacquer perfectly. Constantly we hear from unsolicited sources new uses of Plastic Wood, and the splendid results that are obtained. It is real wood in putty form. Here are some typical letters: “Some months ago a man drove an old sedan up to the shop, the top of which was a wreck and the wood all rot- ten. I removed a portion of the cover, filled the decayed pieces with a pound of Plas- tic Wood, replaced the old cover—and it is still as good as new.” been skated over now for From a Cabinet Shop. two months and it shows no sign of wear.” See NN i naiciitiailias Skating Rink. “Plastic Wood is the best thing I ever saw for patch- ing wood. I used it on the skating floor and now I myself cannot tell where I patched it. The floor has “For general home use Plastic Wood is marvel- ous—the picture frames “In almost every job there are the that are breaking at the usual dents and torn veneers to corners; screens that do contend with, but we do not waste not quite fit; a piece torn any more time on setting in pieces from the tire of the baby in these damaged spots. Plastic : Wood does the trick in short order. a we som harvey 4 bar Rone I also find it to be a most excellent material for repairing split sound- mas tree we made sure ing boards.” that all bolts and screws were molded with Plastic Wood. I have even molded new feet with it for my q small daughter’s f it doll.” . —— “With Plastic Wood I have re- Mrs. O— M— W— paired a wooden chopping bowl which was split entirely in half, and it is now as good as new. Really, your product is without equal in its line.” From a Piano Repair Shop. PLASTIC WOOD Reg. U.S. Pat. Off. Plastic Wood (and Plastic Wood Solvent for softening and thinning Plastic Wood) is regularly carried in stock by Hard- ware and Paint Stores. Tubes 25 cents 4 lb. can 35 cents 1 Ib. can $1.00 Solvent —25 cent and 50 cent Cans Manufactured by ADDISON-LESLIE COMPANY 327 Bolivar Street, Canton, Mass. May, 1930 Stunt Flying (Continued from page 157) tempted fate—once too often. He would take up his old Farman, point its nose at the sky, stall it, and then slide backward. When the nose dropped, he would dive, climb, stall again, and repeat the reckless stunt. A somewhat similar modern stunt is the falling leaf glide. In it, the plane descends in a series of sidewise swings through the sky. To make a falling leaf, I throttle down my motor until the plane loses most of its flying speed. When I feel the controls begin to get “sloppy,” moving easily, I pull the stick all the way back, simultaneously applying full right rudder. The ship stalls and starts to fall off to the right. Immediately I reverse the rudder to full left. The plane continues to swing to the right. The wings gradually begin to tilt to the left. I hold the stick all the way back. At the peak of the right swing, the plane falls off to the left. Immediately T re- verse the rudder to full right. In this manner, [ swing back and forth, the plane continually in a stalled condition. To resume normal flight, I push the stick forward and neutralize the rudder. REMEMBER one time when I didn’t need to push the stick ahead to come out of a falling leaf glide. I was about 1,500 feet up, drifting toward Roosevelt Field. It was a boiling August day. Just as I reached the peak of one swing, a powerful downcurrent of air caught the nose of the ship. The resulting dive straightened us out in a flash. Among the most difficult stunts for a student to master is the spectacular barrel roll. In it, the plane traces a course through the air like a screw thread. To perform it, apply all controls fully at the same time. In a right roll, for instance, I pull the stick sharply back into the right-hand corner of the cockpit. At the same time, I kick over the rudder to the right fully. The nose of the plane rises. Then the ship sheers off to the right. It hangs in this position for an instant. Then it whips into ro- tation. Throughout the roll, I hold both stick and rudder on fully. When the ship has nearly completed a 330-degree rotation, I neutralize the elevators and apply opposite aileron and rudder to stop the rotation. This brings the ship out of the roll in straight flight. In prac- tice, a student should always line up the maneuver with a straight highway or railroad to be sure he comes out of the roll headed exactly as he went in. HE greatest of America’s early stunt pilots was Lincoln Beachey. This reckless dare- devil of the skies used to loop at 300 feet, and his vertical plunge was known as the “ Dip of Death.”’ He knew practically nothing of aero- dynamics. He abused his planes in a thousand ways, and in the end “flew out of his wings” over San Francisco Bay and plunged to death. At the opposite extreme is Jimmy Doolittle, ace of modern aerobatic flyers. He studies stresses and strains, knows just what his plane will stand before he tries a stunt. His feats are works of art. His piloting is as skillful as a surgeon’s handling of his instruments. Mod- ern transport and air mail companies are looking for pilots like that. It is skill, not fearlessness, that such companies want. Once Beachey suggested to the contest com- mittee of an air meet a competition in which flyers should climb to 4,000 feet, then dive vertically and see which could come closest to the ground before leveling off. And he meant it. Such a dive places a greater strain upon a plane than any other stunt. When a ship is leveled off out of a long plunge, the effect is the same as suddenly increasing the pull of gravity threefold or more. I weigh 160 pounds. At the end of a long power dive in a Curtiss Falcon, I am jammed down in my seat as though I weighed 480 pounds. And | the wings are, in (Continued on page 159)

Page 161

1930 — ee DP 1 Dee OS AT ee ee ee | we we SF we Ss? May, 1930 Stunt Flying (Continued from page 158) effect, supporting a ship weighing three tons instead of one. During the war, I used to return from patrol duty high over the home field and then cut the motor, shove ahead the stick, and bring my Fokker down in a screaming 8,000-foot plunge. One of my longest spins lasted for 5,000 feet. Three fast Sopwith “Camels” were on my tail and spinning down was the only means of escape. I started the spin at 10,000 feet and pulled out at 5,000. In coming out of a long dive, delicate handling of the controls is necessary, as jerky movements will pull off the wings. No pilot’s judgment is good enough to dive at three miles a minute close to the ground. Leveling out of a long dive should be done high in the air. Stunting is like rifle shooting. Practice makes perfect. But no one eyer shoots a thousand times or stunts a thousand times without missing once. And when the stunting is done close to the ground, that miss is good- by, nine times out of ten. HILE most stunting demands hair-trigger piloting, occasionally a flyer has to throw his ship around like a tennis racket. I remem- ber such an occasion a little over a year ago. I was flying a couple of news photographers to meet the Graf Zeppelin. We had a fast Whirlwind Fairchild. The Zeppelin didn’t ar- rive when it was expected, so we sat down in asmall field near Sea Girt, New Jersey, to wait. It was nearly dusk when we got word that the big airship had been sighted. I had to take off over the ocean. We were climbing a hun- dred teet above the water when the engine spluttered and nearly stopped dead. I re- member thinking I would have to get that ship back within fifty yards of shore, as one of the photographers couldn’t swim. But the engine caught hold again. We climbed to 2,000 feet and circled back over land. It was getting darker every minute. The motor sounded rough. Suddenly it trembled and pounded. Smoke shot from a cylinder. A piston had burned out. From 2,000 feet, I could hardly see the ground. 1 spiraled down, trying to use my map at the same time, but I couldn’t pick out the air field. The best open space in sight was a small field about 300 feet square, surrounded by high trees. The only way I could get in was through a violent series of side slips. I slapped down one wing and plunged sidewise at a steep angle toward the trees at one end of the field. Then I rocked the plane over and, with the other wing low, slid toward the ground. The camera men screamed. With their arms thrown over their faces, they braced themselves for a bad crash. The plane was hardly ten feet from the ground when I kicked the rudder over, killed the side slip with the ailerons, and sat down heading into the wind. The big ship stopped with a run of a hundred feet. That was one of the hardest landings I ever made because that tiny field, besides being inclosed by trees, sloped uphill. I had to make a right-angle turn and sit down for an uphill landing, all in a split second. It is such landings that test a pilot’s mastery over his plane—the kind of mastery he obtains from stunting. At a safe altitude, stunting is | not reckless flying. It is a pilot’s post-graduate | course. NEW BOOKLET ON HEATING THE advantages and disadvantages of dif- ferent heating systems, information on fuel costs, new heating methods, automatic con- trol, humidifying equipment, etc., is contained in “House Heating and Ventilating,” price twenty-five cents from Popular Science Insti- | tute, 381 Fourth Ave., New York. POPULAR SCIENCE MONTHLY who Fish or Here Are Amazing Innovations in Both Outboard Motors and Boats Johnson Sea-Horse motors— friends of all out- door men—now appear with the two greatest im- rovements in outboard history — Electric-Starting in larger models and Alternate Firing in smaller rope-started models. o match these new motors, Johnson has brought out a line of boats— utterly newand equally amaz- ing. Together these Johnson Matched Units of Motors and Boats put outboard motoring on an entirely new plane. The Johnson Electric-Starter in larger Sea-Horses charges the battery and remains in continuous operation, making the motor non-stalling even at slowest speeds. Also has auxiliary rope-starter. Alternate Firing in Sea-Horses “12” and “4” rev- olutionizes performance in the small and medium classes of rope-started motors. Two sparks per rev- olution cut vibration in half—make starting cer- tain and let you throttle down to a steady crawl. Sealite construction in Johnson Boats is 35% stronger than comparable wood construction and guaranteed to outlast it; yet it is only half the weight in water service. Hence Johnson Boats are decidedly faster and more portable. Sealite is seam- less, waterproof—you never have to calk or bail. See the foatadedidln new Johnson Boats and Sea- Horse Motors at the nearest dealer. Or write us for beautiful illustrated-in-color catalog giving full particulars of all models, prices, etc. All dealers carry first-aid service parts. Stations for complete service in all parts of the country. JOHNSON MOTOR COMPANY, 2591 Pershing Road, Waukegan, Illinois. In Canada: Canadian Johnson Motor Co., Ltd., Peterboro, Ontario World’s Largest Manufacturer of Outboard Motors and Matched Units Right—1714-ft. Service Runabout Has steering wheel, recess for motor, three cross seats with lazybacks and luxurious cushions. True speed up to 27 m.p.b. with Sea-Horse “‘32.’’ The boat, $485. JOHNSON 159 GREAT NEWS for Al Hunt Sea-Horse “4” One of Johnson’s new alternate firing motors which cut vibration in halfand makestarting the easiest ever known in rope-started out- board motors. Electric-starting Sea-Horse 24” World’s most power- ful twin—one of the three Sea-Horses now offered with electric- starter and auxili- ary rope-starter or with rope-starteronly Sea-Horse Prices Sinaie $125; ‘*38,’’ $150; Johnson Boat Prices “Knockabout,’’ $135; “Utility A,” $165; “Util- ity B,’? $275; “Servi t,”’ $485; “De Runabout,” , ce J Luxe Runabout,’ $995; ‘Family penny All prices f. 0. b. factory. Partial pay- MATCHED UNITS SFA-HORSES £ BOATS Left—14-ft. Utility A Sealite construction, round bilge bottom. An ideal boat for fishing andcamping use. The boat, $165.

Page 162

POPULAR SCIENCE MONTHLY

he proof that Ethyl develops more power Right: This is the instrument board of a “knock” demon- stration machine. The watt- in

> ‘ Trop « > nuit iaay meter (at the left) registers st ‘ : ora, Se Qs ; sty bite D> power. The tachometer (at < iockion e " the right) records engine revolutions per minute. When this picture was made, the engine was running on ordi- nary fuel. Below: When the lower picture was taken, Ethyl had been fed into the carbureter. The watt- meter shows that the power has risen to the maximum; the tachometer shows a correspond- ing increase in revolutions per minute.

+ hee cxsoune PP Stare Ot casoune Knocks out that “knock”

EKTHYL® GASOLINE) /» “ QEEING is believing.” These pictures of a“knock” ~convincing experiment in your own car. Use up the J demonstration machine let you see how Ethyl ordinary gasoline in the tank; then fill up with Ethyl. 7 Gasoline will increase the speed and power of your You'll see and feel the difference. 4 motor. A simple valve switches the fuel from ordinary gasoline to Ethyl and back again. When Ethyl goes in, Wherever you drive—whatever the oil company’s 7 “‘knock’”” goes out, R.P.M.’s (engine revolutions per name or the brand associated with it—amy pump bearing 7 minute) increase, power goes up. That is how Ethyl the Ethyl emblem represents quality gasoline of anti- 7 improves motor car performance. knock rating sufficiently high to “knock out that ‘knock”” _Itis the Ethyl anti-knock compound in Ethy! Gaso- in cars of average compression and bring out the addi- | line that makes the difference. This remarkable fluid tional power of the new high-compression cars. Ethyl} was developed by General Motors Research Labora- . tories after years of experiment to find an ingredient which would make gasoline a better fuel. Make this The active ingredient mow used in Ethy! fluid is tetraethyl lead. | ry + A 7 Gasoline Corporation, New York City. © E.G. C. 19308

R. R. DONNELLEY & SONS CO., CHICAGO