Popular Science Monthly 1922-07: Vol 101 Iss 1

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Jack Binns’ RADT O DerartMeNT : ’ wa te fs ~ F 4 - — a5 so ty sr? . ie ON . pe \ a "3 . oe woe | | Eddie Rickenbacker Predicts Huge Passenger Airplane—(See page 35) In This Issue: Herbert Hoover, Henry Ford, sucy Glenn Curtiss, Charles P. Steinmetz 25 cents | ; ott Popular Science Monthly

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The Willard All-Rubber Radio “A” Battery (shown here) is designed especially for radio use. iii eee ee ee Care | ~~ Th if lh a ne er tite Stet es Sabet ons be be ek wes) bse cee pe c'- Se 1 er i ee eee he CCST SESS Pesssceessese ||| | + # .~ : & eeeeees Ten Reasons Why The Willard All-Rubber Radio “A” Battery is Better These reasons, back of the success of this specially designed battery, are as definite as those responsible for the success of the Willard Threaded Rubber Battery, which is now stand- ard original equipment on 195 makes of cars and trucks. Ask for particulars from your dealer or at the nearest Willard Battery Station. The Willard Radio “B” Battery is a 42-volt rechargeable storage battery, with leak-proof glass jars and Threaded Rubber Insula- tion. Assures freedom from frying and hissing ground noises. WILLARD STORAGE BATTERY COMPANY Cleveland, Ohio Made in Canada by the Willard Storage Battery Company of Canada, Limited, Toronto, Ontario THREADED «fi RUBBER Therubber caseis made in one piece, thoroughly insulating the battery from cells to ground and from cell to cell, and effect- ively preventing all ground noises. Plates are insulated with Threaded Rubber Insulation, which by reason of its uniform- ity allows every part of each plate to do an equal share of work. Battery is shipped in abso- lutely Bone-Dry condition so , that it-is brand new when you get it. Insulators are made with spécial heavy ribs to meet the special requirements of the , radio battery. Plates are extra heavy to pro- vide current at steady volt- age for considerable periods. Sediment chambers are large to eliminate all possibility of short circuits at plate bottoms. Posts are sealed by soft rub- ber gaskets, so that solution cannot seep out between post and cover. Terminal post$ are high to permit easy grip of battery clamps. Brass knobs sunk into the sides of the rubber case pro- vide a firm hold for the handel. 1 Handle made of a heavy ™ rod furnishes easy means of carrying the battery. ot ot — hot =F AD et OO O WY

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ay 1l- of ane Popular Science Monthly awn. th Wore “A, * ef wes WEE SEE SUG Ay ea wets SY Se Ow aS VON + EBT YONI: ME IEE OP ERE TES Eth In every man’s life there is one Big Moment when he makes the decision that either robs him of success—or leads on to fortune Your One Chance to Earn The BiggestMoney of Your Life | AVE you ever considered why our H richest men come from our poorest boys? Isn’t it a strange thing that it is almost invariably a young fellow who starts life without a cent in the world, without education, without influential friends—in short, without one single soli- tary advantage—who accumulates millions of dollars? Isn’t it a miracle that inside of a comparatively few years a man can rise from abject poverty to fabulous wealth? Astonishing, certainly—but more impor- tant, it is wonderfully inspiring. For it means that no man need be held down by circum- stances. Once he knows the ‘‘millionaire’s se- cret,” he can put it into operation regardless of all obstacles that seem to block his path. His fancied handicaps simply vanish into thin air. He suddenly finds that everything he touches turns to gold—money flows in upon him—fortune showers him with its favors. Everything he wants seems to come to him just as surely and easily as day comes after night, The Secret that Makes Millionaires But millionaires are not the only ones who use this secret. It has made every great man of history. Think of Napoleon—an unknown Corsican soldier in the ranks—then suddenly startling the world with his meteor-like rise, overthrowing empires, reshaping the destinies of nations! What is this amazing secret that can work such wonders? It is just this: The thing behind all big achievement, whether in business, political or military life, is opportunity. The man who wins is the man who sees his opportunity and seizes it. The man who never rises above the rut is the man who lets his opportunity pass. To every man there comes one BIG oppor- tunity—the golden chance of his life. And in the moment he decides for or against that opportunity—whether he will seize it or let it 24 lg decides the whole future course of is life. , How often you hear a man say: “If only I had recognized my opportunity when it came —if only I had taken advantage of it—I would be a rich man today.” The world is full of such men—they plod along year after year—slaving away, hoping that somehow things will take a turn for the better. But their chance for success is gone— it lies buried in the graveyard of neglected op- portunity. On the other hand, let a man see and grasp his Big Opportunity—no matter how obscure he may be, how poor, how lacking in advantage —and his sudden rise to success will astonish the world. People will gasp at the amazing transformation in his fortunes. Read the life of any millionaire and you will find this to be so. Choose Between Low Pay and Magnificent Earnings This very minute you may be face to face with your Big Opportunity—your one chance to earn the biggest money of your life! Right now your decision may mean the difference between a life of plodding, routine work at low pay and a career of inspiring success and mag- nificent earnings. For now you are offered the very oppor- tunity that has made other men rich, that has brought them more money than they ever dreamed of earning. It is the same opportunity that lifted Warren Hartle, of Chicago, out of a job in the railway mail service, where in ten years he had never gotten beyond $1,600 a year, and landed him in a $10,000 a year job. It jumped Charles Berry, of Winterset, Iowa, from $60 a month as a farmhand, to $1,000 a month. It brought to C. W. Campbell, of Greensburg, Pa., a clerk on the railroad, a position that paid him $1,562 in thirty days. These men and hundreds more have found their Big Opportunity in the wonderful field of Salesmanship. They are all Master Sales- men now. They are earning the biggest money of their lives—more than they ever thought possible—they are engaged in the most fascin- ating work in the world—they are independent, come and go as they please—they meet big men —every minute of the day is filled with thrilling variety. Your Big Opportunity may be here too, in the wonder field of Salesmanship. Perhaps you say you have never even thought of be- coming a Salesman. But before you decide one way or the other, examine the facts for yourself. See what Salesmanship offers you— why it is the best paid of all vocations—why there is no limit to what you may earn. Read the amazing proof that, no matter what you are doing now, you can: quickly become a Master Salesman in your spare time at home— read how the National Salesmen’s Training Association in its nation-wide search for men to fill the great need of Salesmen, has devised a wonderful system that reveals to you every Secret of Selling without interfering in the least with yout’ present work. See how this famous organization helps you to a good posi- tion in the line of Selling you are best fitted for. The opportunity that the N. S. T. A, offers you may be your ome chance to earn the big- gest money of your life, as it has been for hun- dreds of others. But whatever you do, don’t pass it by without getting the facts. Just mail,the coupon below for our free book, “‘Modern Salesmanship.’”’ Let us tell you how the National Demonstration Method will enable you to solve almost every sales problem you are —— likely to meet in a lifetime in the selling eld. Let us tell you about our Electrives System that will enable you to sell any line or proposi- tion. Best of all, let us show you how you, too, can quickly become a Master Salesman. The free book gives full information about this re- markable System of Salesmanship Training and Employment Service. It will show you how easily you can learn this fascinating and big paying profession at home in your spare time, Mail the coupon NOW. National Salesmen’s Training Association Dept. 15-H Chicago, Il, National Salesmen’s Training Association Dept. 15-H, Chicago, Ill, I simply want to see the facts. Send me FREE your Book ‘*Modern Salesmanship’”’ and Proof that I can become a Master Salesman. Also tell how you can help me to a position and send list of lines with openings for Salesmen.

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et tee ietisgehanae cen oes 5 Sate aa re oe

CONTENTS July, 1922 Vol. 101: No.

Broadcasts of the Future By Herbert Hoover Page 19 How Power Will Set Men Free By Henry Ford 24 Commercial Aviation as a Career By Glenn H. Curtiss 35 On the Crest of the Radio Wave By Jack Binns 74 Where Our Summer Storms Come From.................. 20 Teaching a Cranky River to Control Itself................ How a Broken Arm Made an Inventor Wealthy............ 27 Uncle Sam's Super-Junkyard for Battleships............... a ns Linn sina ndble'n ad 66 acne 29 Queer Science Stops Pain by Pressure...............0.-- The Future Airliner, Pictured by Eddie Rickenbacker........ 35 My Ideal Radio Receiving Set.................cceeeeeeee And 172 Fascinating, Informative Articles, which include:

AERONAUTICS . Gasoline-Electric Auto. ................- iia iinet: 53 ag Ag a9 oy ee Car Power.... Testing Anti-Aircraft Guns.............. 59 The Home W orkshop ee aT PTS FOR THE FARMER Build « Radio Se nani “i pane Sineenee uild a Kadio oe | "er ae i i i K3ow to Save Seeds from Birds. .........- 33 Indoor Aerial Helps Overcome Static... .. 79 Sheshinas in the Cost (ine. . Bete Dee Li I h sips Pontoon to Raise Treasure Ships. ........ Seeds Threshed from Cones............. 40 istening In wit meprmt Set.......... 82 Dennen Sa ae ith This S iii, ||... |... ca 48 Condenser Made with Sliding Plates... .. 88 é mEraTe TED SRee Stamp.. pean thy pie tees Bae Wood a 90 Mechanical Smoker Tests Cigar Quality. . Hay Sorted and Analyzed............... 48 peaker of Wood........ = A Coon Fuel Ch ios Ceal 57 Bottle Serves as Aerial leaulaner eee baicas 91 Pocket Knife Carries Outfit of Tools. ... . setae eet Gate sacs 3h || Unanay Ser Cyt Bars’ 32] Spee Medel Shp 7 Poison Gas for Rats............ ee ee ot Taee Mesmmnee. .. .. “Walker” Mends Dog’s Back............ 67 FOR THE HOME ee ee ee sdinseuamaaaaabaan . Blacksmith Carves Portraits............. 78 inten... ransform Tobacco Box into Aquarium... 82 Piet hoi for Ghar HOUSEKEEPING MADE EASY Dusting Radiatore with Air. .--......-.. 83 oe. abinet Makes Brea ixi Ae 83 ESR a ers Tagging Your Umbrella................. * —— deg 9 Charm to the nth oa Re hae 84 —— Film - Fees: RO Re) Meats aed Pa Y ee ee 4 fibeet SROOr EARIOD,... 5 2... -.00000e0 85 ermometers Pass Rigid Inspection. .... Gas Pistol for Fire - Thief So pene Par 54 a ay we as og = ae for Trees. ........ 86 a the nee Fly... eee cece eee eee Ti Ce a eee 54 older Prevents Inkstains.............. Oepatal TOF Huss. 2. 2... ee eee tet eee Midget Washing Bhathine ines tieen.... 2 oe. Make.s. ag 1d — Sprinkler. ...... eae RONEN ARON 6 55 9p 520. 6c crass) %4'0: 5-6 5 i e Drives Ice-Cream Freezer........ logs Pay Income Tax. ...... A Simple Door Awning. ................ : >. ae See >t Clothes-Wringer “Spiele 99 The Whirl of Fashion.......... eo eeeeeees INDUSTRIAL PROGRESS Locking a Ford with the Ignition Key .. 100 Armless Sharpshooter Is Champion....... Irrigating Garden with Overhead Pipes. "* 100 Small Log Pierces Tree................. Hose on Wheels Washes Streets.......... 23 Bottle Cap Remover................... 106 Huge Astronomical Mirror. ............. ——— rte ye merase “4 The Shipshape Home................... 108 os arth ps Want to Know?.......... ap Measurer Saves Lost Motion....... oney Used as Wallpaper.............. Fire Pump Replaces 50 Men............ 23 Violet Rays Detect the Invisible Power Drill and Hammer Combined...... 31 FOR THE SHOP Making Searchlight Mirrors............. Rewinder Feeds Film into Projector...... 33 nonin Makes Socket Wrenches. ....... 77 The Fastest Things in in. eer Portable Welding Outfit................ 34 Clocks Turn Off Store Window Lights.... 80 Race Horses Travel in Motor Trucks... .. Billets Are Squeezed into Brass Rods..... 39 a se pee Eevee. CE lalate a 4 Mirror Permits Shaving in Bed. ......... : : . Or amto wetributor......... B91R Mocs Camen ina. fcc... ee ee of Wells.. my A Soldering-Iron Holder... .............. 102 “a omen il — nee Fire....... i eta — 42 Hoist for Delivering Cement............ 103 N ston . 4 stings say ak Ce How Blind S hee Tak ° ae alate es REENME TMEOB so 0.05 64.5 iss se wes = erves Tested on the Rack............. ow in tenograpl e akes ictation. Gage f or Scroll or Fret Work i Mae ae 104 Linoleum on the Street CO cer errereresece tar ean ae +n ‘vm ee eae = Faaag amen vad ag tag tel in Boiler aie 104 ruit Stamping Machine................ se Borax Freely in Brazing. ...... 107 Magar anes —_— by — Under Board 46 ° RADIO t Holds Lathe Grinder Firm............ 46 Selene Me CnediGa Geidy........ 46 RECREATION Radio Permits First Aid at Sea. ......... Fuse Guards High-Voltage Circuit....... 48 Celebrate Fourth with Carbide Cannon... 79 Music for Broadcasting................. i 49 Making a Sail for a Canoe... ........... 80 Broadcasting Invades New Fields........ Canvas Doors Form Movie ‘‘Prison”’..... 52 aw voy arg ‘Cowl -Go-Round.......... nf Fountain Pen Is a Check Protector....... 52) OR) fee eee ae Welder Seals Uneven Seams............. 52 Casting Rod Made from Blu _ a» 10 SHIPS AND SHIPPING Street Car Arm Forms Safety Zone....... 54 Sand Dump Will Amuse the Children. ... 105 a ame eet 2 ‘weaned Beis eens 54 Sag Ph pg ery nen A Find U —.... Senin 107 as aes Being NEE ustless lron Holds Polish. ............. 54 o Fold a Nia BUM. win oc oe e's 107 Iceberg Detect ANac Picusnt iin, Air Blast Mixes Concrete............... 58 | How to Take che ictures.......... Wt , ee Sener nate SEPA iant cases Coon) Go POMCK... occ ccc cetecs 60 | Bricks Travel in Cartons. ............... 61 = Ten Type from One Record. ............. 6l TPRRES AD CARTES eenee panoneat Finest Art......... 63 Massage and Keep in Trim. nner Tubes Prevent Pipe Bursts... ..... 64 One Musician Becomes an Orchestra... .. Huge Rotor Rolls 10 Miles in 10 Days.... 64 Copyright, 1922, by the Modern Publishing Co. Make sitar pine Crane Lifts and Dumps Cars............ 67 POPULAR SCIENCE MONTHLY Bicycle Generates Current for Lamp sine Concrete INE 5 sc ininis:t wre wee sevens 67 225 West Thirty-ninth St., New York City A Golf-Ball Retriever............. ie : : Adjustable Set-Square for Drawing Angles 66 Issued monthly. Single copy, 25 cents. The Origin of P. ‘ogo PMRONB So fe.o.0s-.<1<< ie. 5/5.6 yeaay subscription for any part of the world, ning — te “7 Up. .......-.00e, : the Umpire........! Rie ax MOTOR VEHICLES AND ACCESSORIES tt ead eahee = “" = Sonered as Steel Tape Winds "kine ee eee second-class matter Dec. ’ , at the Post les Add P i RRBs Gas ona ana —- Sten SAR ere 34 og yi el pag — He act of March = he asl ee. beckon ae peeders Curbed at Railroad C 34 ntered as second-class matter at the . icin Weighing Jacks lem ie eaigag oli so Post Office Department, Canada. Printed in cb _ a . pe ey ee eats Semi-Overalls Protect Trousers L 40 U.S.A Sa on Se 0 gual Ton Colada 5. Me 4 yt egs...... Sag ‘contents of this magazine are copy- Apron Avap tor GDWis, . «<2. 6): sieves y eam Truck Is Practical... 45 righted and must not be reprinted without Fantastic Summer House from Mud...... Motorcycle for Cost; Auto for Comf i Adj mn c oy aeegt all agg re 48 permission. H. J. Fisher, President; R. C. Tire Tube for a Swing............--.+-+ + justa e reeper a Comfort. ...... 51 Wilson, Vice-President; O. B. Capen, Secre- Archer-Golfer “Drives” Arrow. .......... Chance Ti gage —— tee e wees 54 tary and Treasurer. Amplifiers for Banjos................... ange Tires in a Few Seconds.......... 59 Sam Loyd’s Puzzle Page ...............

Popular Science Monthly

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$100 in Prizes Offered in This Issue—See pages 31, 66, and 83 |

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- Popular Science Monthly July, 1922; 25 Cents a Copy; Vol. 101, No. 1 $3 a Year Published in New York City at 225 West Thirty-ninth Street — N MANY American homes, people are ask- ing, ‘How are future de- velopments of the radio- telephone likely to affect us?” No one is in a position to answer all the implications of this question. The possible expansion or retrenchment in the broadcasting of entertain- ment, the extent of lasting public demand for musical programs of the present type, the method by which, in the long run, these programs will be financed—all these mat- ters hinge on unforeseeable contingencies. Those who have become interested in radio in the past few months have reason to believe, however, that there will continue to be many out. What Next in Radio? ERBERT HOOVER, Secretary of Commerce and probable radio dictator of answers in this statement the questions about broad- casting that are being asked more frequently than any others this summer. Everybody who has invested in a radio receiving outfii—or expects to—is wondering just how large and lasting his dividends in entertainment will be. Secretary Hoover—even now the most important gov- ernment official concerned with wireless—will become, in effect, supreme ruler of our radio destinies if recom- mendations of the Washington conference are carried His statement for POPULAR SCIENCE MONTHLY may be considered, therefore, to have unique authority. the United States, up almost overnight an enor- mous new economic activity, the growth of domestic radio seems almost providential. While the era of slackened business was still painfully with us, and while the opin- ion was general that people did not have money to spend, this marvel developed, stir- ring the popular imagination and inducing the spending of money for radio apparatus literally by millions of dollars. Perhaps, when it is all over, and we can look back at the event, we shall see that this faseinating new national util- ity, springing up abruptly outside the existing frame of industrial life, arousing public enthusiasm and stimulating increased buy- agencies that will want to supply the public by radio- telephone with interesting information that the public, in turn, will desire to receive. While the broadcasting of music has been the first phase of the radio boom to attract attention, the transmission of the spoken word in addresses, sermons, and lectures will eventually be one of the most popular and best appreciated functions of the broad- casting stations. Universities, churches, and state and Federal governments will, it seems obvious, find the broadcasting of news, talks, and information an increas- ingly vital’ factor in their service to the public, while I believe the public will ulti- mately find the greatest interest in just such material. The wildfire spread of radio has, of course, been much more amazing than any other thing we have seen in our time. One is at a loss in trying to think of any phe- nomenon to which it can be compared. There are moments in history when the normal course of economic progress is sud- denly intensified, and for a time we live in - a veritable furnace of revolutionary activ- ity, from which we emerge with a new agency of civilization in our possession or a new industrial weapon at our command. Apparently, we are in the midst of such a period now. We are all so closely in- volved in the radio expansion that it is futile to attempt to predict where it may lead us. enthusiasm which we must all feel for its future, even if we cannot visualize that future, we may say at once that the tre- mendous speeding up of activity in all establishments connected with the manu- facture and sale of radio apparatus has been a contribution to economic revival. We know, of course, that the spectacle we see today has been in preparation be- hind the scenes for many years -in the laboratories of great inventors and of enter- prising manufacturing establishments; yet, coming at the moment it does, building Aside, however, from the intense - ing, was one of the im- portant factors in bringing commercial activity back toward normal. Meanwhile, questions as to the future home uses of radio are inevitably ever pres- ent in our minds. It seems not unreason- able to believe that in the long run much of that future lies with government and public broadcasting. We are witnessing, indeed, the dawn of a new day in communication. It is a dawn glowing with the promise of profound influence on public education and public welfare. Colleges, churches, educational and lec- ture foundations, and government depart- ments will almost certainly find in the future that radio broadcasting has become a vital part of their work. The home in which a radio set is being installed may confidently look forward to the receipt from the air of an ever increasing quan- tity of important and interesting in- formation from many sources that have never before been so accessible to the American public. 19 ES TT TT MT NT ea

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KOS See he fee aad , re: or

in NOT tte agers = 9@MUNDER HEADS” *

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TYPICAL thunder storm, showing the air disturbances that occur in its path. From the front of the storm, which is moving toward the right, warm air from the earth’s surface as- cends through thie cloud, while air cooled above or within the storm itself rushes downward, causing cool winds to flow out on all sides. These wind gusts are strongest at the front of the

storm because the forward movement is added to their velocity. Along the front, tumbling between the rising and descending currents, there is often a “squall cloud” that brings the first heavy dash of rainfall. Topping all is a high cloud sheet over- flowing from the thunderheads and extending forward, some- times for miles. These clouds form the storm’s ‘“‘advance guard.”

The Secrets of Death-Dealing Storms Science Explains Cloudburst, Tornado, and Thunder Shower HO has stood fascinated bythespec- nothing was known about the origin, char- them has been unfolded during the past tacular approach of a menacingly acteristics, or movements of storms. In 50 years. This knowledge has come after black thunder cloud, waitingforthe fact, practically all our knowledge about long, painstaking study; for the meteorolo- summer storm to loose its fury, without wondering where it came from, how it was formed, and where it accumulated its store of energy that suddenly beats down upon the earth in the form of raindrops, hail- stones, or whirls of wind? The thunder storm, hail storm, cloudburst, and “twist- er,” that often sweep paths of death and destruction during the summer months, seemed mysterious acts of supernatural vengeance until the scientific explorer began to learn their secrets and to trace their origin. Then he discovered that they originate where they end—at the surface of the earth. The sun warms the earth, which in turn heats the lower air. This warm, moist air, because it is lighter than the air above, rises in currents. Ascending, it expands as the pressure of the surrounding air diminishes, and cools into water vapor that accumulates in clouds and floats in the air like fog, buoyed up by rising air currents be- neath. The Storm Clouds In this manner are formed the storm clouds, of strange shapes and shades, that under certain conditions of tempera- ture and moisture assail us

Here is a remarkable photograph of a Nebraska tornado at close with hailstones, rain by the range. An eyewitness says: “From the base of what appeared gist has been unable to repro- duce storms in the laboratory for experimental purposes. He must study them as they occur or as they have been recorded. Most people are familiar with hailstorms that cause great damage to growing crops. Probably many readers have seen hailstones as large as hens’ eggs. But probably few of us would believe that hail could fall in sufficient quantities to delay railroad trains, or in stones of sufficient size to kill cattle. Yet such was the case at Gray, Iowa, during the night of Aug. 7 and 8, 1883, when the drifted hail covered fence posts and held up trains, and when 26 head of cattle were killed. Some of the larger hailstones measured 13 inches in circumference. How Hail Forms Hailstorms are simply thun- derstorms in which the vertical air currents within the storm cloud are of unusual magni- tude. Hail falls only in con- nection with thunder storms. But comparatively few thun- der storms precipitate hail. Hailstones are formed when raindrops are carried by the vertical currents up into the region of freezing tempera- tures. As soon as the frozen

“bucketfuls,” or whirling winds. At the beginning of the nine- teenth century practically to be an ordinary 8torm cloud this funnel-like ‘twister’ began to taper downward in a long streamer, finally reaching the earth. The progress of the lower part was slower than that of the upper, so that when the streamer was elongated to about 114 miles, it parted at the center. The lower part continued on its course’”’ drops drift out of the area of strong updraft, they fall back into the region of liquid drops, where they become coated with a thin film of water. But

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Srily, 1922 they are again caught in the updraft and again carried into the region of snow and ice, where the new coating is congealed. This. may happen several times, producing hailstones of various sizes and structure. Finally, however, they become too large to be sustained by the ascending currents, whereupon they fall to earth. Sometimes the hailstones, when broken through the center, show plainly the series of concentric shells about a small nucleus, formed in the manner described. Why Thunder Storms Bring Hail The reason that hail does not fall except in connection with thunder storms is that the vertical ascending and descending air currents that carry the raindrops up into the region of freezing temperatures are not present in other types of storms. part of the thunder storm from which hail Hail never falls except at the beginning of the storm. The reason is that the front is the only part of the storm in which ascending and descend- Owing to the small cloud area in which it is formed and the high speed at which the storm moves—from 30 to 40 miles an hour—the duration of the hail at a given location seldom exceeds a falls is near the front. ing currents exist. few minutes. Sometimes the storm contains two separate areas from which hail falls, so that the damage occurs in two This was the case in the remarkable hail- storm of July 18, 1788, which passed from Touraine, France, into Belgium, damaging crops to the extent of about The two bands were One was about 10 miles wide and 420 miles the other, about five miles parallel but separate bands. $5,000,000. about 12 miles apart. long; wide and 500 miles long. Equally remarkable are some of Seven inches of rain fell in 90 minutes at the cloudbursts of history. Cambridge, Ohio, July 16, 1914, the greater part falling in 30 min- utes. When we say “seven inches of rain,’”’ we mean that if the total amount of water falling should re- main where it falls, it would stand seven inches deep on the ground. A depth of rainfall of seven inches is equivalent to 3614 pounds of water a square foot of ground sur- face, or about 800 tons an acre. If you can imagine rain falling so fast that you can hardly breathe, you ‘realize how the rain fell at Cambridge. Persons who were driving through the town at the The OUTWARD EXPLOSIVE PRESSURE "6 LBS. 10 SO.IN.. ~~ How a tornedo causes a building to “explode.” Air pressure inside the twister is reduced in the case pictured, to 9 pounds to the square inch, while in- side the building pressure is normal at 15 pounds. Thus pressure of 6 pounds to the square inch pushes the walls outward ENGLISH CHANNEL ae This map shows the paths of a remarkable hailstorm that passed from Touraine, France, into Belgium in 1788. from two separate storm clouds, advancing About $5,000,000 damage was done to crops in two distinct parallel bands about 500 miles long side by side. BELGIUM Above is another astonishing photo- graph of an approaching tornado, taken at Antler, N. D., Aug. 20, 1911, from a d:stance of 114 miles. Such twisters are formed by violent upward air movements in a storm cloud which form an eddy or whirl within the cloud. This whirl rap- idly extends downward like a whirl- pool. lower the funnel extends. center a partial vacuum forms The dotted line indicates steps in the for- mation of a-hailstone. From upper clouds a frozen drop falls to a warmer level, where it is coated with moisture. Then it is lifted by another rising warm air current, Hail fell to earth. its water coating freezes, and it falls again. This process is repeated until the stone becomes too heavy to be borne upward, and it falls Inset shows how a hailstone is built up intothese icy layers The stronger the whirl, the In the time said that they were greatly alarmed for fear that they would suffocate, and that the rain was falling so fast they had to hold their hands over their faces to breathe. Engineers generally compare rates of rainfall by calculating the total depths of water that would fall in one hour if the rain continued at the same rate for that length of time. Thus in a cloudburst at Porto Bello, Panama, in May, 1908, rain fell at the rate of 30 inches an hour; that is, if the rain had con- tinued an hour, the total amount of water that fell would have equalled a depth of 24 feet on the ground. Such a depth would be equivalent to 156 pounds of water a square foot, or about 3400 tons an acre. Size of Drops Limited Professor Humphreys, of the United States Weather Bureau, a recognized authority on meteorol- ogy, has determined that raindrops cannot be larger than a fifth of an inch in diameter, and that they cannot fall through still air faster ’ than 26 feet a sec- ond. - These limits are due to the re- sistance of the air. If a drop becomes larger than a fifth of an inch in di- ameter, the air fric- tion on its surface becomes greater than the force of cohesion that holds the water together,

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22 and consequently the drop breaks up into two or more smaller drops. Similarly, when the velocity at which it falls reaches 26 feet a second, the friction of the air on its surface, which is tending to keep it from fall- ing, becomes equal to the force of gravity, which is pulling it down, and _ there- fore it cannot attain any increased speed. Eleven Drops in Cubic Foot If it is assumed that in the Porto Bello cloudburst the raindrops were all of the maximum size, a simple arithmetical com- putation shows that there must have been 286 raindrops falling on each square foot of surface each second. If they were falling at the maximum possible speed, there would have been only 11 drops in each cubic foot of air at any instant. Consid- ering the cloudburst in this way the un- usual record does not seem impossible. Think of the power that would be available if such a cloudburst could be harnessed! Thirty-four hundred tons of water falling in an hour from a height of a half a mile, which is about an average height for the lower surface of the clouds in such a storm, would represent 10,000 horsepower. This would be only for one acre; for one square mile the energy would be 6,400,000 horsepower. Cloudbursts above Pueblo, Colo., June 3, 1921, resulted in a flood in which 120 lives were lost, and prop- erty throughout the valley was damaged to the extent of about $20,000,000. Cloudbursts are simply heat thunder storms in which the rain- fall is unusually great. Heat thun- der storms are those caused by the rising and cooling of large masses of warm, moist air, called convec- tion currents. As the air rises, it gradually cools by expansion, soon reaching the dew point, whereupon condensation of moisture and the formation of a cumulous cloud, or thunder head, begin. As the air continues to rise and to cool, con- densation continues and the cloud becomes larger and larger, finally becoming a thunder storm. The drops of water within the cloud also grow larger and larger until finally they become too large to be sus- tained by the upward currents, or drift out of the direct path of the rising air, whereupon precipitation begins. Storms Grow as They Advance Such thunder storms generally form on hot, sultry days, usually in the afternoon. As they move across the country they grad- ually increase in size, sometimes attaining a front of 200 miles and a depth of 40 miles in six or seven hours, which is about the average life of a thunder storm. The rates of rainfall are generally higher during the early life of the storm, when the cloud areas are comparatively small. The heav- iest rainfall occurs near the front of the storm, at about the time hail falls. One interesting but as yet unexplained fact in the movement of thunder storms is that they are unable to cross large rivers. In some cases this probably accounts for the rainfall reaching cloudburst propor- tions. The storm, reaching the river, is stopped and held stationary for a time, so that the unusually heavy rate of rainfall usually present near the front of the storm, The cloudburst is simply a thunder storm in which ’ the rainfall is unusually heavy. It is an often ob- served fact that thunder storms are unable to cross large rivers. Reaching a river, the storm is held stationary, pouring its accumulated load of moisture in a deluge upon one spot for an unusually long time. The theory advanced for the checking of a storm at a river is based on the presence of a wall of comparatively cool air above the water, which prevents the rising of warm air currents to which the thunder storm owes its existence is continued over the same territory for a much longer time than usual. Sometimes large mountains cause the storms to stand still, thus creating cloudbursts. One theory to account for the fact that thunder storms cannot cross large rivers is the presence of the comparatively cool air over the water. The thunder storm owes its existence to a huge mass of rising over- heated air, fed in from the front arid sides, principally from the front. When the storm reaches a large river, it encounters a mass of much cooler air, so that its supply of heated air is very much diminished. This condition may be responsible for the storm stopping and dropping its accumu- lated load over one spot. Cloudbursts also occur when two or more storms moving in opposite directions come together and consequently remain stationary for a time so that the high rate of precipitation is continued over thésame area. History contains many references to storms in which various foreign objects, such as oranges, frogs, and fish, fell with the rain. References to showers of blood, or of sulphur, are particularly numerous. The so-called showers of blood were simply Popular Science Monthly ——~ This mountainous “cumulus” cloud is built up in hot weather when great volumes of moisture- laden air, heated at the earth’s surface, stream rapidly upward, cooling by expansion. Invisible water vapor becomes visible cloud. If the process continues far enough, the mass of cumulus becomes the thunder cloud storms in which dust particles having a reddish color were brought down with the rain in sufficient quantities to produce definite color effects. In these, the unusual precipita- tions, the foreign substances, orig- inally came from the earth, just as did the rain, the only differ- ence being that while water is evaporated directly into the at- mosphere, the foreign substances are lifted only by whirlwinds, dust storms, tornadoes, or similar phe- nomena. Having been lifted into the upper air currents, they are carried along with the storm until vertical currents diminish to such an extent that they are no longer able to support the foreign matter. The tornado that is capable of lifting and carrying heavy substances appears to be caused by an unusually violent development of upward air move- ments in a cumulo-nimbus or storm cloud. This upward rushing of warm air, under certain conditions may become strong enough to form a whirl or eddy within the cloud. This air whirl, when once set up within the cloud, readily extends downward. Whirling Air Creates Vacuum The centrifugal force of the whirling air creates at the center a partial vacuum in which some of the moisture in the air con- denses, forming a funnel-shaped cloud. And the stronger the whirl becomes, the lower the funnel cloud extends. When- ever it extends clear to the ground, the partial vacuum within the “twister’’ tends to destroy or pick up whatever may lie in its path. Tornadoes have been known to make buildings ‘‘explode,”’ to carry children a mile or more, lodging them, unhurt, in treetops; to drive straws into boards and to carry heavy stones high in the air.

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July, 1922 One-Horse Hose on Wheels Washes Streets FIRE oot sen nena street washing on a retail scale has been achieved by the town authorities of Baker, Oregon, through the use of a strange pipe line on wheels, similar to the smaller pipes used abroad. The town had water to spare, but the amount of hose required to reach some of the streets made street flushing an unwieldy proposition. An ingenious ngths of iron pipe, mounted on small trucks and joined by rubber hose, form the Le foot hose line citizen finally hit upon the idea of con- necting 50 lengths of three-inch iron pipe with short sections of rubber hose, and resting the flexible pipe line thus formed upon small iron wheeled trucks. The completed line is 500 feet long, but because of the rubber joints the water system can be quickly bent in any direction or even turned back upon itself. Motive power is supplied by a horse hitched to the front section of pipe. All the operator has to do is to direct the flushing nozzle. Portions of streets that are distant from hydrants may be reached easily by means of this pipe line. Camera Photographs by Its Own Illumination O FACILITATE the task of fingerprint experts in the detection of crime, George Blum, official photographer of the San Francisco Police Department, has devised a special camera that supplies the illumination at the same time that it is recording the view. Near the front of the camera is a plug for connecting six small bulbs on the inside with the outside lighting source. These lights are located around the lens but not within its field. Thus a perfectly and uniformly lighted object is obtained—a vital consideration in the photography of delicate lines such as fingerprints. SEEDS from American trees are being sent to Europe to renew forests destroyed dur- ing the war. The American Forest Asso- ciation has supplied 25,000,000 seeds from Pacific Coast trees to England alone. These include Douglas Fir, Sitka spruce, and Western larch, which seem especially suited to climatic conditions there. 23 Fire Fighting Pump Will Replace 50 Men JX THE future, forest rangers in Minne- sota will fight fires with new portable pumps light enough to be carried by one man instead of relying upon gunnysacks, picks, and shovels to open fire lanes. The pump weighs less than 75 pounds, including a gasoline engine with its 3-quart tank filled with gasoline. Its capacity is 20 gallons of water a minute, and it will throw a stream 140 feet in the air. Forest fires cannot be controlled with water, but the pump wets down the open How the forest ranger carries the portable fire fighting pump fire lanes and prevents the blaze from crossing them. It is estimated that one pump will take the place of 50 men using pick and shovel. Map Measurer Saves Lost Motion in Factory H°wW many miles of travel can be saved yearly in a factory by a scientific re- arrangement of the routes along which materials move? This is a question easily solved by Major Frank B. Gilbreth, efficiency expert, using a pocket map measurer. ‘ In studying a problem of this sort, Major Gilbreth first makes a ground plan of the factory, with all machines in place and to correct scale. He then maps out the possible routes of materials from the begin- ning of the manufacturing process to the completed product. By traversing each route with the map measurer, he can indi- cate the shortest routing. The map measurer consists of a marking wheel, which is made to travel along the routes, the exact distance being recorded on a dial calibrated in feet, meters, and miles. ce te 5% ep Bs D seer fT rind On this exact model of the ground plan of a factory, lines are drawn denot- ing the routes along which materials might move. The wheel device shown in the inset moves along these lines, recording the distances

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Popular Science Monthly How Power Will Set Men Free My Ideal of City and Farm Made One By Henry Ford In an interview for POPULAR SCIENCE MONTHLY with Searle Hendee ENRY FORD’S dream of America made over by a vast development of our water power resources is here presented in an interview by the writer who last month sketched for POPULAR SCIENCE MONTHLY readers a vivid picture of Henry Ford, the man. Human health, happiness and prosperity will be achieved in fuller measure than ever before, Henry aN. Ford believes, in the agricultural-industrial commu- nities which he prophesies in this extraordinary article. WATER FLOW AUTOMATIC SPEED CONTROL 4 7 HIS is the age of power. Pa Electricity and gasoline are emancipating the human race from the slavery of primitive drudgery. The America of 50 years hence is taking shape now. To visualize it, to picture the de- tails of the civilization our children will live to see, it is necessary only to look about and see what’s going on. Peo- ple are growing more intelligent every year, yet it is surprising how few really know what is taking place on every side of them. Power is the key to to- HERE morrow, just as yesterday it was the key to to-day. The ony difference now is that we are speeding up—we are learn- ing to make greater use of what we have. We are in a period of transi- tion. q Whereas we have been AND CASING OF” grinding along with eyes fo- HYDRAULIC. VALVE cused in the ruts of obsolete methods, we are turning into C the highway of greater intel- ligence. We are changing WATER ENTERS Po S M4 Le MFT. NEEDLE GOVE RNOR CON T ROLS SPEED OF WHEEL ELECTRIC sk GALLERY fi gears, and before long we shall be covering more ground with less fuss and effort. Power the Answer What has built every great metropolis of modern times? What has caused thousands up- on thousands of young men and women to leave farms on which they were born and reared, to seek employment in our large cities? Why are boys and girls and men and women of the cities healthier, better read, more progressive, younger for their age, and as a whole more versatile than persons who have spent their lives on old-fashioned farms? “Power” is the answer. Ready accessi- bility of power built our cities. It caused people to leave the drudgery of farm life and avail themselves of the advantages found in thickly populated centers. It has made machine production possible, and this in turn has brought shorter working hours and better working conditions. Since a day’s work in the city has involved fewer hours, less physical effort, and has offered oppor- tunity for broader use of the mind than has farm labor, the individual has benefitted 26 Everv farm blessed with a creek or river Niagara Falls. the electric generator. This giant descendant of the primitive hydroelectric plant shown in the upper right hand corner, is in use at The huge turbine is capable of developing 55,000 horsepower from the impulse of falling waters and is designed to run at a speed of 187.5 revolutions a minute under a 305-foot head of water. valve at the left the water rushes in to whirl the blades of the turbine and drive the shaft, which is surmounted by After the water has given the use of its power, it escapes through a spreading tube into the tailrace at the right accordingly. Shorter working hours have meant more hours for personal improve- ment. But manifold as are the advantages and attractions offered by the city, numerous also are its disadvantages and hardships. Centralization of power has caused central- ization of industry. But this cannot be ex- panded indefinitely, and anything that can- not be expanded indefinitely is wrong. If you place working people in an unattractive environment, huddle them together in im- possible tenements, crowd and pack them layer upon layer in cramped, stuffy, dingy streets, eventually you will get a kick-back. One must remember when considering the human element that children cannot be excluded from the equation. It is true that —r- GENERATOR oa ¥ 2 A INSPECTION Through the hydraulic corners wherever there are corners to cut, | POWER DELIVERED ” BY BELT Facey GATES FOR CONTROLLING | —— t as SS : ~ PELTON BUCKET ss Vi op WATER ENTERS > (i One of the first hydroelectric plants in the United States, irstalled in 1887 by the Roaring Fork Electric Light and Power Company. in Col- crado. The impulse bucket wheels at the right are toy size compared with the mam- moth modern Pelton wheels of the same type, which often weigh 25 tons the city child benefits from advantages at present denied children in many rural dis- tricts. And it is also true that the composite product of the city is one of the finest types of individuals we have. Going a step further then, it is not diffi- cult to recognize that by ccm- bining the advantages of the city with those of an improved country, everything would be on the side of human advance- ment. And we cannot look at the city to-day without seeing its slums and tenements as well as its parks and boulevards. It goes without saying that thousands of city children grow to maturity under conditions that are as far from inspira- tional as are those that have hampered the natural develop- ment of many a country-bred boy and girl. “City” of the Future Our present system is not sufficiently flexible to meet satisfactorily the variable conditions presented by the humanelement. And therein lies the over- whelming disadvantage of the city. Ex- pansion beyond a certain point. results only in congestion, and this in its various phases lessens the values otherwise grow- ing out of centralization. Picture a community possessed of all the advantages and none of the disad- vantages of the city, and you visualize the kind of place where American people are going to group themselves. in the future. I contend that the light of mod- ern developments shows that the trend is toward the semi-rural community. This in turn will be the “city” of the future. There is a basic need for it; it is logical Popular Science Monthly At our plant we are just getting 1 Cone, ee: zea Af = ee i ee ee

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July, 1922 more useful. land is tillable. Is This to be the City a Tomorrow? Here is the city of to-morrow as conceived by Henry Ford —an azricultural-industrial community in which, he believes, life for every individual will be healthier, happier, less monotonous, and At intervals along the banks of a stream, like * jewels on a string, these communities are situated where natural power is easily available for hydroelectric development and the At each interval is a dam giving sufficient head other. of water to supply power without waste for the factories and homes of the community. between agriculture and industry, devoting a few weeks in the spring and fall to the one, and the intervening months to the Linking the communities on each side of the stream are thoroughfares for surface and underground traffic, as illus- trated in the inset at the lowcr right © VU. & U. Above is one of the crowded tenement dis- trict scenes that Henry Ford contrasts with his ideal of the future city, where all will share the advantages of town and country i ff ( ! { IK \h AV vTCTON CATT TN TUTTE TTT The inhabitant divides his time and therefore it will be. For lack of a more descriptive name, we will call this coming “city” an agricultural-industrial village. It will be situated wherever nat- ural power is available and the land tillable. The reason for all this is almost too apparent to give in detail. First of all, the same thing that made the city what it is to-day, is beginning to make the farm what it should be. Power, in other words, is revolutionizing agriculture. To-day even farming may be made the most attractive and profitable business that is open to the aggressive individual possessed of an active mind. In the tractor, truck, automobile, and stationary gas engine; in power-driven appliances and electricity, we have the facilities that are making farming enjoy- able, profitable, and worth while. Any- thing possessing these three attributes is attractive to individuals endowed with imagination and energy. And therein lies the crux of the whole situation. By taking power to the farm, we are abolishing its disadvantages and leaving all of its pleasant aspects intact. But this is not the end. Power on the farm goes further than merely making agriculture a pleasant and lucrative occu- pation. It does more than shorten the farmer’s working day. It enables him to accomplish everything on a general farm in about three weeks each year. Farming in 21 Days This is not theory—it is practice, on my 5000-acre farm at Dearborn. There is not a horse on the place. Tractors and power machinery do everything there is to be done—from plowing the soil to harvest- ing and transporting the crop—and they do it in 21 working days. For the balance of the year the rest of the work is left squarely up to Nature. We fall-plow while we are harvesting. That is, our plows usually follow the reapers. By the time the crop is off the ground, the job is cleaned up for the time being. A little later we put the tractors into the fields again and harrow and seed. Nothing could be simpler. This in turn means something more. The city chap will want to turn to the farm. And since there is no profit in primitive drudgery, the reactionary type of farmer who endeavors to hold out against progress will be replaced by the youngster who can see ahead. The fact that there are still in America farmers who cut their grain with cradles, means nothing. There are thou- sands who are using reapers. And there are thousands more who know the value of the tractor because the automobile has blazed the way for it. The tractor carries power of one kind to the farm. The small stream that winds through the fields brings still more power. And in the very near future this latter source of energy will be fully utilized,

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sar Sie er ston se BS wt pee “ eae ae ee ETS ie real 26 Every farm blessed with a creek or river will have its own hydroelectric installation. I have nine dams across the little stream that passes through my property, and I develop between 400 and 600 horsepower. On the other hand, the stationary gas en- gine will solve the problem on farms where water power is not available. It is not to be imagined that 11 months of idleness will characterize the life of the coming farmer. Here is where the rural- industrial community comes in. The auto- mobile makes it unnecessary for a man to live on his farm. He can reside in a pleas- ant village miles distant and have the com- forts and advantages of the small city rather than the soli- corners wherever there are corners to cut, and yet at best it’s expensive and unsatis- factory. America’s rivers offer enough power to turn every wheel, heat every room, and light every building and street in America. When this great source of power is properly utilized, coal will be as unnecessary as tallow candles. This being apparent, think now of what water power development will mean in the Mississippi Valley, beginning at the headwaters of the Mississippi and the rivers emptying into it, dams, hydroelectric installations, factories and prospering com- munities! And economically, what will be Popular Science Monthly At our plant we are just getting ready to make tractors. Up to this time we have been experimenting and developing. There are not more than perhaps 300,000 tractors on American farms to-day. Millions of them are needed—so we are getting ready to manufacture. Motor cars will be used even more uni- versally in the future, because changing conditions are making them more indis- pensable. Also one must not forget that motor-trucking, now in its infancy, will hasten the changes that are coming. So far as the so-called fuel situation is concerned, we have always had our calam- ity howlers. We shall have gas- tude of the farm. The “new farmer” will demand this. He will not live five miles from his nearest neighbor — he will live next door to him. This is only natural, because in a large per- centage of cases he will be either directly or indirectly a product of the city and by nature will ‘“CNOME people have too much and some too little, as a result of imperfections of our economic system. even distribution. That is one reason why I indorse Henry Ford’s water power idea so highly.”,—THOMAS A. EDISON. We need more oline as long as we need it. Itis true that we are getting poorer grades now than we did some years ago, but what difference does that make? Motor cars are getting more miles to the gallon today than ever before. In other words, we have im- proved the internal-combustion engine and are able to use crave companionship and revolt against isolation. For the same reason he will require continuous employ- ment. Every creek and river afford a natural source of power. Along the banks of our innumerable streams will spring the rural- industrial communities of tomorrow. Manufacturers will build their factories where power and labor await them, instead of hauling coal to city plants and expect- ing labor to seek them out and live under impossible conditions. True, this is revolutionary—it is some- thing to think about and reckon with. It will upset, to a degree, our present system. But it can be expanded ir definitely. There- fore it is economically sound and likewise inevitable. The man who isn’t ready for it, the business that isn’t prepared to adjust itself to it, had better get ready, for it is coming as surely as greater enlightenment, greater happiness, and a greater race are coming. The Plan Works in Practice The type of community to which I refer is not unknown at present. Here and there in various parts of the country, small fac- tories and large are springing up along all sorts of streams, making use of water power and utilizing native labor. Only the be- ginning, of course, has been made. But the plan is right, because it works. Take it in our own case. We havea num- ber of small factories scattered around in little towns close by Detroit where water power is available and where we are now making parts for our cars and tractors. Over at Plymouth, for instance, all of the pistons for the Lincoln motor are made. And the workmanship is unusually good, too. I am not sure but that it shows the effect of the conditions under which the shopmen are living. ‘At Northville we have another factory, and so on. At one point we make one thing, at another, another. We find the plan works out splendidly. But whereas we have hydroelectric power—the best and cheapest power on earth—in our small plants,’we burn coal at Highland Park. Coal is just about the most inefficient and expensive fuel there is. Anyway we find it so, and I doubt very much if there is any one in the country who is using coal more economically than we are. We utilize all of the by-products—even getting enough benzol out of it to pay for its transportation from the mines—cutting the result? We shall make use of power that is now wasted; we shall conserve the human effort and expense now expended in the mining and transportation of coal; we shall automatically abolish the flood prob- lem, thereby saving millions annually; and, furthermore, we shall raise the standard of life while meeting the problem of living and lowering the cost of it. The United States is a network of rivers and small streams, all of which offer us the most vital thing in modern life—power. The Mississippi alone is sufficient to guar- antee the future of the United States. It is not to be expected that the indi- vidual installations will be projects of tre- mendous size. The contrary will more generally be the rule. And it is because of this that industrial communities will follow the shorelines. First of all, huge develop- ments—such as the Keokuk project on the Mississippi—represent too much waste. The loss of power in long-distance trans- mission is tremendous: It is more economi- cal to utilize the current near the place where it is developed. Secondly, if you have facilities for developing three or four times as much power as you can possibly use within a given radius, your overhead immediately becomes ruinous. In developing the Mississippi, it would be practical to construct a dam for about every 15-foot fall. This would give a long series of dams of moderate head, which would pass the full flow of water every 24 hours without waste, for use would be found for all the power thus generated. It seems to me that this is about the way it will eventually work out. Tractors Increase Production To return to the tools of progress: Of all modern machines, the tractor is one of the greatest mechanical blessings that has been devised for mankind. Not only does it enable more work to be done in less time and at far less expense than heretofore, but it makes possible better work. Fields cul- tivated by tractor-drawn plows produce more than fields turned by horse-drawn ones, just as the latter increased the produc- tivity of the land when it succeeded the crude wooden plow of more primitive days. Tractors make deeper plowing and subsoil- ing possible. ‘This in turn enables the ground to give up the best that is in it, and renew itself, instead of gradually wearing out. poorer grades of fuel without difficulty. But we have not gone as far in this direction as it is humanly pos- sible to go. From year to year we shall continue to find ways of improving and refining our motors so that they can accom- modate the fuel that is at our disposal. But suppose, for the sake of argument, we should actually exhaust our oil resources, exhaust even our vast shale deposits. What then? Would motor cars and tractors cease to exist? Should we go back to breeding horses and oxen? Enough Alcohol for All Needs When we have need of alcohol for fuel purposes, it will be produced commercially in sufficient quantity to meet all require- ‘ments. There is enough alcohol in an acre of Michigan potatoes to plow the acre of ground that raises them for a hundred years! The “fuel problem” will take care of itself. It need be no source of worry now. America is a vast storehouse of raw materials. So far, we have neither scratched the surface of its resources nor caught other than a faint glimpse of its possibilities. On every hand opportunity awaits the use of power, brains, and human energy. We can make of America and ourselves what we’ will. We have everything with which to work, and our final result will be good regardless of how many years may be spent in attaining it. Unemployment, poverty, and wasted lives are as unnecessary as the system that makes them possible. Any social order that is not self supporting, that continually has to be patched up, bolstered along and lifted over rough places by means of poor- houses, bread lines, relief work, and what not, has neither the right to exist nor the soundness with which to endure. When we make power our slave and util- ize it as fully as is possible in the light of present understanding, when we reduce the work of feeding and clothing ourselves to the simple formula that is within oir grasp, we will enter upon a new and better plan of life—a plan that will not simply make for happiness and general welfare, but one that will enable us to develop ourselves intel- lectually and morally to a point more nearly in keeping with what should be. Individ- ually we shall be better balanced men and women. We shall exercise alike our brains and our muscles. We shall oe healthier, happier and of greater use to ourselves and those about us. Popular Science Monthl Ju dov and emp tice at S he chi ate was by § in tk dis« fina! mac full opel cut pres was rat wai =F. Fh O MP eH ct ct Ss OL oa— Clete lel eee

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July, 1922 How a Broken Arm Made Inventor Wealthy 27 Tailor Hoffman's Luck Was to Fall Downstairs, and He Turned It into an Idea for a Steam Presser that Won Him a Fortune By John Walker Harrington health. With him he took his creation, think- HEN young Adon Hoffman fell headlong down a dark stairway and broke his arm while employed as an appren- tice in a little tailor shop at Syracuse, New York, he conceived the idea of a clothes-pressing ma- chine that he could oper- ate with his foot! That was an accident. Developing his idea, by sheer determination, in the face of ridicule and discouragement, he OW many brilliant ideas have been-lost, merely for lack of motive power to push them to practical use? “The lucky dog!” we sometimes exclaim, when an inventor hits upon some valuable discovery and turns it into success. If you are inclined to believe that sheer luck or a chance idea is more than incidental in successful invention, read this story of an 18-year-old boy who was “lucky” enough to break an arm, who had a bright idea, and who turned this idea into wealth by grit and long hours of hard work. ing he might induce Westerners to have their garments smoothed out with it. Even then he did not fully grasp the full possibilities of its ap- plication to the great clothing industry. In Seattle, where he worked for a while, he pressed a few suits, but the results of his revolutionary ma- chine methods failed to cause any noticeable wave of enthusiasm. He finally perfected a steam decided that Syracuse machine that not only success- fully replaced the clumsy hand- operated tailor’s ‘‘goose,’’ but cut in quarter the time and labor of pressing a suit of clothes. That was invention. **Adon’s Steam Arm” Less than a score of years ago Hoffman’s steam clothes press was rated as afreak. It was the source of gibes from his brother tailors. It was such an outlandish looking affair that they christened it “‘Adon’s steam arm,” and predicted jit would meet a fate similar to that which befell Adon’s real arm at the : bottom of the stairway. But today you see this same steam press, with the improve- ments of years, at work in the windows of tailor shops throughout the land. It has made its way to nearly every corner of the globe where clothes are worn. Since 1908, when it was first put on the market, 46,000 machines of all types have been manufactured and sold, and annual sales have increased from $95,000 the first year to $4,147,141.61 in 1921. That was good business! If successful invention consists of everlasting plugging in order to turn a chance idea to practical use, then Adoniram J. Hoffman may be “Q@AY, young man, what are you doing?” demanded the dismayed insurance agent, as he saw his best trousers disappearing into the jaws of a strange, steam-spitting contraption that resembled, to his perturbed vision, a hissing alligator. The insurance man’s amazement as_ he watched the primitive model work, marked the beginning of success for Hoffman’s ‘‘steam arm,” for he became interested in raising capital to place the steam presser on the market and went back there, establishing a small clothes cleaning and dyeing shop. Here the mud of Syracuse, chanc- ing to spatter the trousers of a cer- tain insurance agent, opened the way of new opportunity. In the office of a hotel in the upstate city sat Theodore Palmer, wet, draggled, a bit muddy, and tired, watching the New York Central trains as they steamed and splashed through one of the downtown streets. Finally, Mr. Palmer’s eye rested on a sign in the window of a shop across the tracks, which bore the legend, PANTS PRESSED HERE WHILE YOU WAIT “Why don’t I?” he said to him- self. He waded over the swirling, muddy street to the little shop, where he met a tall, slight youth. The Beginning of Fortune “T’d like ’em pressed,” said Palmer. “Take them off,”’ replied the in- ventor. Now this was hardly as impres- sive a greeting as Livingstone gave to Stanley, but it was the beginning of something brand new. In the discreet seclusion of a curtained alcove, Mr. Palmer divested him- called an ideal inventor. Today, in the prime of life, he possesses wealth, leisure, and the means of still greater en- deavors in invention. Hoffman was 18 years old when the acci- dent that shattered his working arm con- vinced him that he could no longer wield the tailor’s heavy iron, and that if he was to make a livelihood at his trade he must find a means of pressing clothes with his feet. At least, the idea was worth trying out. And Adon, born of sturdy New York farmer stock, tackled his problem with a determination that refused to be dampened by ridicule or apparent failure. Before his arm was out of splints, he began to construct the strange machine piece by piece, substituting a board filled with steam for the heavy iron goose that more than one old-time tailor still pushes over the clothes of customers. He had little money to spend on patterns and models, but he saved all that he could out of his slender wages, and invested it in templets, gaspipes, cast-iron frames, and a small steam boiler. The more he worked on his steam clothes press, the more he felt that he was going to save a great deal of labor. “Tf I hadn’t been so exceedingly lazy,” he remarked, recalling those early days, “I should never have got anywhere.” There is an early picture of the inventor which shows him without coat or waistcoat and wearing baggy trousers and a skimpy shirt. He is standing before his new press —of which his own raiment seems in dire need—looking at it bashfully, for he was always opposed to having his pictures taken. Toiling night and day to perfect the de- sign of his steam press, Hoffman finally broke down, and decided to go West for his self of his breeches and settled down to read a pink sporting paper devoted to heavy weight pugilists and burlesque queens. Suddenly he was aware of a loud sizzling that strangely mingled with a pounding noise. Peering from behind the cretonne hangings, he saw his best trousers disap- pearing down the jaws of what, as nearly as he could observe, was a steam alligator. “Say, young man, what are you doing with those?” he demanded. “I didn’t tell you to can them, didI? What is that thing you are putting them in, anyway?” Flinging about him the dressing gown provided for such emergencies, he entered the workroom and watched as Hoffman operated the first steam clothes press. “Have you patented this machine?” asked Palmer. “It is patented,” returned Hoffman, pulling on a steaming trouser leg. - was a pretty good place, after all, © 4 ~ “

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ay ~ Spa's > igs Seo = $e 28 “Then why don’t you do something with it?’ insisted Palmer. ““Can’t—haven’t any money.” “How much do you want?” inquired the insurance man, drawing the Turkey red bathrobe around him and dropping the newspaper on a convenient chair. “Fifteen thousand dollars would do,” responded Hoffman. ‘‘Got it in your coat? I didn’t see it in these jeans.” “We'll get it right away,’’ Palmer prom- The operation of the steam resser is shown in the diagram aw. While upper and lower “*bucks”’ or pressing boards, operated by a pedal, hold a garment under pressure, the opening of a valve sends a cloud of steam into them from the small boiler at the right. Another pedal operates a vacuum mechanism that gucks moisture from the garment % SWIVELING STEAM INLET UPPER BUCK STEAM ISSUES STEAM AND SUCTION PEDAL ised, and was almost as good as his word. Then and there began the marketing of the Hoffman invention on a large scale. The company was established in Syracuse with a capitalization of only $3000, and the first steam press was placed on the market in 1908. That first year, machines were sold to the value of $95,000. During each year that followed the sales climbed steadily, and the demand continued to in- crease. The original $3000 was the only subscribed capital ever put into the busi- ness, which was built up entirely by the re- investment of profits. The Public Was Skeptical At the outset, the inventor sold the ap- pliance to a world that was skeptical. Palmer insisted that Hoffman go out ‘‘on the road” as chief sales agent, while he, Palmer, ran the factory and tried to get up financial steam. The work of placing the machine on the market was slow at the start, and for a time the only sales office was a small room adjoining the offices of the attorney of the company in Wall Street. The business expanded so rapidly, however, that before long Mr. Hoffman was relieved of the selling so that he could devote his time to further improvements. Several years ago he retired, having made a large fortune. Numerous improvements have been made in details of the steam press, but the essential principles are the same in the crude original and in the highly specialized types of the present day. The device sug- gests somewhat the mangle of the old-time laundries. It presses the garments slowly between two surfaces that resemble small ironing boards. By the operation of a treadle, the two boards are brought closely together and held by a powerful leverage with a pressure that may be regulated from an ounce to aton. When the garment is Adoniram J. Hoffman, the inventor, and the Since _ the friends of his youth. newest model of his steam when with $3000 capital resser. e placed his machine on the market, the company which he founded has manufactured and sold about from This business was built up entirely from Hoffman pressing machines are used throughout the world 46,000 pressers, and sales have increa $95,000 the first year to $4,147,141 in 1921. enormous reinvested profits. Today in position between the boards, the turn of a valve pours a cloud of steam into the upper and the lower pressing surfaces, which are connected with pipes to’a small boiler. The boiler is equipped with a powerful gas-burner, which roars like a Bunsen flame. The steam makes a con- tinuous circuit when that effect is desired. There is an ingenious arrangement, how- ever, worked by a small treadle, which creates a suction much like that attending the passage of a train through a tight tun- nel. After the application of steam and pressure, this suction treadle operates to draw out all the air, steam, and moisture from the clothes. In almost less time than it takes to tell, the garment is perfectly dry, pressed to the proper shape. For pressing coats, there are heavy pads which can be placed in the sleeves to retain the proper shape. The speed with which a suit of clothes can be pressed by the machine method varies from 15 to 20 minutes, according to the skill of the operator and the nature of the fabric. The tailor using goose or gas _iron requires about one hour and a quarter to complete the same work; and even then the garments must hang for a while before they are dry enough to wear. Several hours, indeed, may elapse before the old- school tailor feels that his suit is ready for a journey into the world again. From 50 to 60 suits a day can be pressed by the Hoffman press, while only about 15 can be turned out’ by hand methods in the same period. The highest speed record for pressing a suit of clothes by this machinery is eight Popular Science Monthly - minutes. At this rate, if a tailor had a line of eager customers all day, he would have anywhere from $30 to $40 in his pocket by nightfall. The steam press has been put to a wide variety of uses in the clothing industry. Special forms are used now for shaping the canvas linings of coats, pressing the collars, arranging the back seams, and in general giving the garments a spick and span appearance. Fully 65 of these special types of presses have been made for clothing fac- tories in the manufacture of men’s and women’s garments, knit goods, hosiery, and underwear. In the large plants, the steam is drawn from one boiler, and there is a vacuum chamber that serves to draw in the water vapor from the damp cloth. Some large clothing factories operate as many as 200 of these machines. Hotels, steam laundries, and pressing and dyeing establishments also use the ma- chine extensively. Aids Other Inventors Now that the inventor has made a fortune of his own, he enjoys assisting other struggling inventors in their enterprises, discussing with them their possibilities of success and giving them valuable advice. In Syracuse he is interested in a big industrial plant, a store, and also a butcher shop kept by an old school- mate of his. He never has forgotten When he is asked to talk of the secret of success for young men, Mr. Hoffman declines. Heseems to pre- fer to lend a helping hand to the young inventor, assisting him along the road to success, rather than to talk about himself. Electric Woodworker Can Do Fifteen Jobs A NEW portable woodworking machine, electrically driven, is a combination saw and planing mill that will perform 15 different woodworking operations. Its ca- pacity limit is hard wood two inches thick. By a series of adjustable stops the car- penter can cross cut, rip, and miter as well This combination saw and planing mill, electrically driven, is portable as do joinery. Tenons, dadoes, bevels, and plows may be turned out as fast as on the large size stationary machines. The new tool is light enough for a carpenter to carry in his car to a job, where it will work on any electric-light socket. \ July, 1! Ld | c elemen written one of charact point of H to sa with ele in their | if they 2 newest must w clearly 1 Hithe that ha light, a1 by engi With a servant But : a little than th of a k experin as he subject biddin; cinatin enthus unders than | come € Aga man t must daily small limit portu cal 2 trical him, pract Fi the ¢ mate unde ours “it. “ the num sigh clos ther of 1 engi B gint

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\ July, 1922 | 29 The A-B-C’s of Electricity A Simple Story of the Elementary Principles of the Most Mysterious Force Controlled by Man “I consider this article on the elements of electricity not only well written and technically accurate, but one of an extremely worth while character, looked at from a_ broad point of view.” —Dr. Charles P. Steinmetz. ‘ke has brought hundreds of thou- sands of persons into close contact with electricity as an important influence HE tremendcus interest in radio in their lives; for they have discovered that .. if they are fully to enjoy the benefits of this newest marvel of communication, they must understand its secrets a little more clearly than ever before. Hitherto the mysterious, unseen energy that has given us the telephone, electric light, and street car has been handled for us by engineers; it has been made foolproof. With a button or plug we have made it our servant. But successful use of a radio set requires a little more skill, a little more knowledge . than the pressing of a button or the turning of a knob. It invites investigation and experimentation; and the layman, as soon as he takes up radio, discovers that the subject of electricity, which seemed for- biddingly difficult before, becomes a fas- inating study. He can ride his wave of enthusiasm for radio straight into a better understanding of the elements of electricity than he ever had before. The lessons be- come easy and interesting. Again, it is impossible for the average man to acquire a knowledge of the interest- ing ways of electricity from books alone. He Protection of Radio So many owners of radio outfits have inquired about the possible danger to their sets from lightning during the summer and the best means of protection, that POPULAR By Dr. Charles Sets from Lightning SCIENCE MONTHLY put the questions up to Dr. Charles P. Steinmetz, the world’s authority on lightning. His answers, written especially for the benefit of radio beginners, follow, P. Steinmetz LIGHTNING pre- sents potential dan- ger to wireless sets and in all cases due precau- tions must be taken. The most inexpensive and practical one is grounding the set. If indoors, the ground can most effectively be con- nected with the city water pipes in the house. Assuming an_ outside aerial, care should be taken to ground it thoroughly by connecting the wire with metal plates and putting these several feet underground. The technical reason for lightning’s preference for jumping a short air gap —the simplest of lightning protectors —rather than passing through the set to the ground is found in the phenome- non known as electrical inductance. Lightning invariably chooses the short- est path to earth and the one of least resistance. In passing through wires, particularly wires containing coils, electricity encounters back pressure that impedes ready passage; sets up, in other words, a counter effect that must be overcome. Rather than attempt to Dr. Charles P. Steinmetz overcome this, _ light- ning, possessing a tre- mendous electrical pres- sure, prefers to pass across a gap of air, which it can readily do. The amount of energy in a thunderbolt, according to recent calculations, is estimated to average about 50,000,000 volts. It is difficult to deter- mine the limits within which a radio set may be operated safely before a thunderstorm becomes local in nature. This would be governed largely by the amount of static and other local conditions. Will static ever be entirely eliminated? Possibly not, but I believe the annoyance that it now causes will be greatly less- ened. I think that apparatus will be made to prevent static above a certain in- tensity from affecting the line. After that, what static comes through with the mes- sage itself, may be filtered out by proper tuning. Since radio messages travel at some regular frequency and static has no frequency, the solution looking toward its elimination will probably be the per- fecting of some existing filtering process. long tube, air must be using electrical apparatus daily. His radio set gives him, ona small but interesting scale, and in a limited but marvelous field, the op- portunity to deal daily with electri- cal appliances. Theories of elec- trical conditions become clear to him, because he is dealing with practical applications of them. Finally, since electricity is one of the greatest agencies for mankind’s material welfare that has ever come under human control, we owe it to ourselves to know all we can about -it. The great radio boom opens up the opportunity, then, for vast numbers of people to obtain an in- sight into a subject that has been a When you blow through a diminished by friction on the sides of the tube, until it is far less at the end of the pipe than at the mouth. Electrical resistance is similar. Current Passing through a wire is im- peded to a degree that depends on the size of wire pressure is closed book to them. It will bring them nearer to an understanding of the achievements of electrical engineers and research laboratories. Because it is hard for radio be- ginners to make headway through Voltage in an electric circuit may be likened to pressure of water as it flows from a tank down- ward through a pipe. Just as the water flow increases as the tank is raised higher above the outlet, so the flow of electric current through a wire increases with the amount of voltage or pressure from the source the mass of textbooks and manuals at their disposal, an elementary statement of seme of the A-B-C’s of electricity may prove helpful. None of us knows what electricity is. No man can isolate a portion of it and hold it up for others to touch, taste, or feel. But we do know how electricity acts, through long experience and experiments. For a clear understanding of electricity there are three terms with which we should be acquainted at the outset. They are “volt,” “ampere,” and “ohm.” Since electricity is considered as flowing through conducting substances just as water flows, the simplest method of describing the three terms is by comparison with the properties of water. Consider a water system made up of a tank of water on a housetop, with a pipe leading to the ground. Now, if water is allowed to flow down the small pipe, it will leave the lower end with a certain pres- sure and in a certain volume. The volume is sélf evident, and the pres- sure can be noted if the finger is placed over the opening, as if to stop the flow. This pressure corresponds to the voltage in an electrical cir- cuit, and the water volume corre- sponds to the electrical amperage.

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9 a Se Seca 4 ee Ae 30 If a larger pipe is then used for the water flow, the volume of water will be increased, but the pressure to the square inch will re- main the same, because the height of the water tank has not been changed. On the other hand, let us suppose that the size of the pipe is decreased until the opening is very small. Neither the pressure nor the volume will then be tricity flowing steadily for 15 hours, making 60 ampere hours altogether. If the same battery is connected with a small motor which consumes a current of four amperes, the motor can be run at full speed from the battery for 15 hours. (Of course, in actual Popular Science Monthly ~ 1 ampere, it can be operated for the full 60 hours before the electricity entirely runs out. The storage battery and its electrical charge may be likened to a water tank that is not completely filled with water, but has an air space between the surface of the How the _vario- great. The pressure should be the same, but the friction of the water on the sides of the pipe has taken away some of the pressure energy. The effect is the same as if a large crowd of people were coupler (at left) and condenser (at right) operate ina radio set is ex- plained below in terms of a hot- water system water and the top of the tank. Into this space, air under pressure is pumped. If this air is maintained constantly at the same pressure, the water that is forced out will flow with the same pressure, although the vol- ume will vary according to the size of opening in the tank. There is a certain quantity of water in the tank, and this may all be taken out at once, or a small flow be permitted for a relatively long pushing and plung- ing, in an attempt to pass through a narrow passageway. They be- come wedged into the opening, with the result that the number finally passing through the passage is considerably less than might go through if there were no crowding. The water leaving the large tank swirls through the small pipe, creating friction on all sides, but finally emerg- ing as a trickle. The resistance to flow on the part of the pipe is exactly the same as electrical resistance. Electric current, in attempting to pass through a wire, is impeded to a degree that depends on the kind of wire, its size and its length. Just as in a pipe line, where it is conceivable that the length of pipe would be so great that no water would reach the end, so in an electrical circuit a sufficient length of wire can prevent any trace of an electric current from passing through it. Overcoming Resistance But in the example cited above, even if the water is unable to fight its way through the pipe, all hope is not lost; for by increasing the pressure in the tank the water can be actually forced through the pipe, overcoming the resistance. Similarly, in electricity, the voltage must be raised, when it is desired to send a given current through a circuit having high resistance. The unit of resistance is the “ohm,” which is usually considered as the amount of resistance requiring one volt of pressure to force one ampere of current through a circuit. Because it has always seemed so simple to use electricity by merely tapping into a plug con- time. The storage battery, in the same way, is charged with a certain number of electrical units. All of them may be removed at once, or they may be allowed to flow out slowly for a long TARTING with the heat generator at the right, follow the arrows indicating the flow of water through the pipes. When the hot water reaches the coils at the left of the diagram (corresponding to the primary coils of the variocoupler), heat waves - dissipated from the pipe pass to similar coils (cor- responding to the variocoupler’s secondary coils) in a second water circuit. Here the heated water rises, passing to the tank shown in the center (correspond- ing to the radio condenser). When the volume of water reaches the limit of the tank’s capacity, it springs a trap that opens the hinged bottom of the tank, and rushes out in a sudden avalanche. As soon as the tank is emptied, the door automatically closes and the tank fills again. The condenser in a radio circuit operates like the water tank. Electric waves entering the circuit through the aerial pass by “induction” from the primary to the secondary coils of the variocoupler and into the condenser, where they pile up. When the condenser has all it can hold, it suddenly dis- charges all the stored up electrical energy in an avalanche. This operation is repeated hundreds of thousands of times a second practice the amount of electricity given out from the battery can never be quite as great as that put into it, but for purposes of comparison, this fact can be disregarded.) If, on the other hand, the battery is con- nected with a motor that consumes only one period. “Induction” and “Capacity” Next to the volt, ohm, and ampere, the two terms most frequently en- countered by the wireless enthusiast are “induction” and “capacity.” These words have a highly technical sound, and the amateur is prone to shy at them. The terms need be studied but little to be understood. If hot liquid is passed through a copper pipe with thin walls, the heat will be transmitted to the outside of the pipe, and will then be dissipated into the surrounding air in the form of heat waves. Similarly, if an alternat- Ing current is sent through a copper wire, invisible waves of magnetism will emanate from the wire and gradually extend their radius until they are com- pletely absorbed by the air. This radiation of magnetic waves is called “fnduction.” One of the best examples of the ap- plication of induction is found in the transformer so frequently seen on the poles of lighting companies. A trans- former consists of two separate coils of wire, with a core of soft iron in each coil. When a current of electricity is sent through one of the coils, millions of these magnetic lines will be radiated. The second coil, being placed near the first, will be affected by the magnetism, and currents of electricity will be started and maintained in the second coil. Induction is personified by the tuning coil in radio outfits. Tuning coils, because of the form of their wind- ings, produce the maximum nected with a seemingly in- exhaustible supply of the energy, it is natural to form the idea that electricity has substance. An idea of how it ean be handled in quanti- ties is suggested by the storage battery, which is an essential part of the better type of radio receivers. A storage battery must always be charged before it can be used. Charging con- sists of connecting the bat- tery with a source of electri- cal energy, until: all the energy the battery can hold has been taken in and ab- sorbed. Let us assume that the battery has a capacity of four amperes of elec- “Modern Jove” Tells of Thunderbolts genera FRANKLIN pulled lightning from the clouds; but Dr. Charles P. Steinmetz created lightning on earth. The “modern Jove” of the Gen- eral Electric Company is supposed to have learned more scientific facts about lightning in the past few years than man had known in perhaps a million years before Terrorizing and fascinating mankind since the days of the cavemen, lightning has at last been made a subject of intensive research. What Doctor Stein- metz—studying lightning and playing with his own homemade _ thunderbolts—has recently discovered, he himself will disclose in a special article for POPULAR SCIENCE MONTHLY readers next month. value of induction for their purpose. Although the cur- rent in the radio waves, as picked up by the antenna, are exceedingly weak, they are strong enough to induce another current flow in the secondary of the tuning coil, whether it be of the loose coupler or the vario- coupler type. Loose coupler induction is not essential, as is proved by the fact that signals can be received with a simple tuner, having only one coil of wire, but currents in- duced from one coil to an- other make it possible to tune-in one station and tune (Continued on page 109) July York has | simu instr exan time bells wou effec men inst: mor typ octé sire

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Eee eee eel er lO ere el Lh lCUMLSC DOO UC!ThC SC C<Citi‘iS sé

July, 1922 31

Te

Massaging the left leg is combined with bending movements of the trunk

To Keep in Trim without Strenuous Exercise, Try a Massage ON THE theory that body massage is a more effective health builder than the usual run of calisthenic exercises, Albrecht Hensen, of New York, has worked out asystem of massage movements that has received the indorsement of some of the foremost physicians. No special ap- paratus is required. The movements are carried out almost entirely with the fingers and the palms. The motion is similar to that of rubbing the skin, but its effect reaches the nerve layers and the inner organs. It is claimed that these exercises improve the circulation of the blood and lymph, enrich the blood, burn away fatty tissues, build up muscles that are hidden away and seldom used, and revivify the nerves and glands, thus producing better health and an improved figure. The most beneficial results are obtained, according to Mr. Hensen, by combining the massage movements with deep breath- ing exercises and with bodily exercises such as bending, stretching, and circulating

Movements for massaging the chest are combined with breathing exercises movements of the arms, the bending of the trunk backward, forward, and to the side and bending and stretching the legs.

A CONTROL device, invented by Wil- liam J. Maxwell, of Brooklyn, New York, makes it possible for a person who has learned to play one instrument to play simultaneously any number of other instruments in harmony and rhythm. For . example, the inventor, playing the banjo as the master instrument, at the same time plays the xylophone and orchestra bells. Ordinarily at least three musicians would be required to produce the same effect. When the player of the master instru- ment strikes a chord, the secondary instruments accompany it with har- monious chords of their own particular type, either on the same octave, or an octave above or below, whichever is de- sired by the performer.

One Musician Becomes Whole Orchestra

The inventor and his ‘‘orchestra’”’ The combination is made possible by electrical contact on the fingerboard of the master instrument,. which mechanically works the other instruments.

$50

Make Money with Your Camera OU’RE missing lots of profitable fun this summer unless you have joined the growing army of POPULAR SCIENCE MONTHLY readers who are out with their cameras to win Three Prizes Each Month These prizes are offered by POPULAR SCIENCE MONTHLY for the most interesting photographs of new inventions, mechanical and scientific achievements, or personal adventure. The prize-winning pictures in POPULAR SCIENCE MoONTHLY’s camera contest for July, appearing on other pages of this issue, are: FIRST PRIZE, $25—Sydney W. Green, Fresno, Calif. Subject— ‘*Wire Cables Act as Bridge Girders’’ (see page 46). SECOND PRIZE, $15—Florence L. Clark, McGregor, Iowa. Sub- ject—‘‘Corn Fuel for Firing Brick Kilns’’ (see page 57). THIRD PRIZE, $10—J. R. Schmidt, Cincinnati, Ohio. Subject— “Fantastic Summer House Formed from Mud Pile” (see page 58). Send in Your Photographs And remember, if they are sufficiently newsy and interesting, they will be paid for at our regular rates, whether or not they win a prize. $50

Power Drill and Hammer Combined in One Tool (COMBINING a power drill and a ham- mer in a single tool, T. S. Payne, of Lincoln, Nebr., has invented a portable ma- chine that will drill holes in steel, wood, or stone. The change from drill to hammer is accomplished by a quarter turn of the milled head just below the motor. One universal electric motor of 3/16 horsepower supplies power for both opera-

Hammering and drilling holes in cement with the combination tool tions. It turns at 10,000 revolutions, and is geared down to 1000 for drilling, and 2000 for the hammer’ The chuck will take drills from 1/16 to 5% inch; bits up to one inch, and chisels from 34 inch for iron or steel to 114 inch for stone. The entire assembly can be taken apart readily for cleaning and repairing.

Drills, bits, and chisels that can be used with che machine

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Popular Science Monthly Coal Machines Make American Miners World Champions NCLE SAM is the world’s champion coal miner, thanks to Yankee in- genuity in inventing machinery with which he is able to dig annually 200,000,- 000 tons of coal more than Great Britain’s output—and that with a quarter of a million fewer miners. In the 30 years from 1890 to 1920 pro- duction of bituminous coal in the United States increased fivefold, while the output of anthracite doubled. The bituminous output for 1890 was 111,302,322 tons; in 1900, 212,316,112 tons; in 1910, 417,111,- 142 tons, and in 1920, 556,563,000 tons. A decrease to 406,990,000 tons in 1921 was due to unsettled industrial conditions: The tremendous part played by time- and labor-saving machinery in filling the nation’s coalbins is shown by comparison of figures for the average output of the underground worker. In 1901, when only one fourth of the bituminous coal produc- tion in this country. was mined by ma- chines, the average annual production of each miner was 729 tons. Eighteen years later, with machines mining 59.2 per cent of the total production, the individual’s average output jumped to 1134 tons—the greatest output in the history of the world. The old-time method of mining coal by pick is rapidly becoming a lost art. Less than 10 per cent of coal mined in Ohio in 1920 was taken out by pick method; more than 80 per cent of the output was mined by machines and the remainder by stripping methods eh oh Ra ek aa Slow, arduous shoveling is supplanted by this portable loading conveyor. A scoop, attached to the machine by a rope and pulled by a capstan, carries the coal to the mouth of the conveyor, where it is lifted into the car Performing the work of 10 men, the rock dump- ing machine shown above builds its own track and hauls itself up an 18 per cent grade, while hoisting and automati- cally discharging 240 cars of mine rock a day. A steel cone-shaped spreader underneath the dump throws the rock to the front, clear of the’ machine, thus building the roadbed. When the bank reaches the height Operated by’a portable electric air com- pressor, this drill bores holes for the ex- plosive that blasts the coal from roof and walls of the mine of the tracks, the ma- chine advances to a new position under its own tractive power Bits rotating at 240 revolutions a minute tear away coal loosened by “shots” and carry it to the loading conveyor. This machine can load 150 tons an hour The slow-going mule has been replaced by this storage battery locomotive in hauling cars. Note the cleanliness of the modern ccal mine tunnel This tank car sprayer, carrying water under high pressure, moves along the mine tunnel, shooting sprays in every direc- tion and laying the dangerous mine dust

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July, 1922 33 Huge Pontoon to Raise Treasure Ships from Ocean Depths UNKEN $s ships with cargoes worth millions will be raised in 24 hours from depths as great as 350 feet —far beyond the reach of divers, if a gigantic pneu- matic salvage ma- chine invented by J. W. De Vito, of Boston, proves as effective in the full sized machine as tests with a model indicate. The salvager is a colossal pneu- matic pontoon enough to enclose aship. Triple hy- draulic plungers force steel arms through the silt under the bottom of the wreck, and other plungers bring the parallel hulls together. A pull of 17,- 000,000 pounds can be applied. Compressed air, admitted to the tanks, will give the salvager an effective lift of more than 50,000 tons. An inclined that opens and shuts like a ciam- shell dredge. When lowered over a sunken hull the great jaws close about the wreck. Water is then pumped from the air chambers of the pontoon, which rises to the surface bearing the wrecked vessel in its grip. The invention may revolutionize sal- vage operations. At present, 90 feet is about the depth limit from which ships can be raised effectively. Thousands of vessels are lying with their sunken treas- Guided by an inclined track, the pontoon sinks into position above a wreck, two hollow hulls close about the vessel, and the pontoon rises with its treasure ures at a depth of about 300 feet. The fact that 18 of these wrecks contain $635,410,000 in specie alone indicates the value of the treasure that may be recovered. The completed machine will be as large as two full-sized ocean liners. Two hol- low hulls, each 500 feet long, are con- nected by great joints at the bow and stern so that they can be opened wide track, or guide col- umn, directs the course of the sal- vager as it sinks into position over the wreck. Theoretically and mathematically the machine appears to be practical, since the forces that can be applied seem adequate. Crushing of the pontoons is avoided by equalizing the pressure on the interior and exterior, either by means of wide open seacocks or the presence of com- pressed air. Automatic Rewinder Feeds Film into Projector OW to recover a motion-picture film for a second run through a projection machine without rewinding has been a mechanical problem ever since the movies became popular. Now Charles F. Herm, of New York, claims to have invented a successful automatic rewinder that will fit into the space assigned to the rewind reel in the ordinary commercial projection machine. The film is taken off a used reel, placed upon the rewinder, and the ends are then clipped together so that the entire film forms aloop. The beginning of the picture _ is on the inside of the film roll, which rests upon aroller bearing. As projection begins, FILM PAID ies - OUT HERE ~~ a> the bundle of film is bearing by a motor. As the film turns ‘over the stationary bearing, the strip winds on the outside, and the inside turns will be loosened. As fast as slack appears on the inside, however, it is taken up by a driving sprocket, which feeds the film into the projector. The result is continuous operation. rotated upon this Red Lead Keeps Seeds Safe from Birds HEN the United States Forest Serv- ice began its work of reforestation, scattering tree seeds in woodlands thinned by lumbermen, so many seeds were eaten by birds and chipmunks that few trees sprouted. But now the seeds are treated with red lead in a way that makes them inedible without detracting from their vitality. The seeds are spread on canvas strips and thor- oughly mixed with finely divided red lead, which clings to them, so that animals and birds leave them alone. Amateurs Can Engrave with New Electric Stamp you can engrave your name in the barrel. of your fountain pen by a new em- bossing stamp operated with electricity. It is so designed that a person of limited ex- perience can cut the letters with no danger of cracking the pen. The embossing stamps are set in the periphery of a disk, and heated by the electric current so that they melt the rub- ber as it is brought into contact with them. A simple clamp, tightened by a thumb- screw, holds the pen firmly and moves it forward under the embossing wheel, spac- ing the letters perfectly. Any material affected by heat may be engraved with this machine. As a special service to readers, the Editor will be glad to supply the} names and addresses of manufacturers of devices mentioned in this issue

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$4 Portable Welding Outfit Takes Little Space A NEW and extremely compact welding outfit that may be carried wherever oxyacetylene gas is available permits the garage owner to use the equipment any- where in his shop without sacrificing space. The entire outfit of torch, extension tubes, gas regula- tor, and hose con- nections fits in a case Jess than 15 inches square — slightly larger than the case of a fold- ing typewriter. In the smaller sizes, the tips are of brass instead of copper, and are secured to the head by a fine- thread nut that is said to provide a perfectly gastight connection. The mix- ing chamber is in the head of the torch. The welding outfit and its case Popular Science Monthly Speeders Curbed at Railroad Crossing OOLPROOF protective curb- ings that compel the careless driver to approach railroad L- tracks slowly have = recently been in- vented by K. W. Carter, of San An- tonio, Texas. Instcad of a gate, the approach to the crossing is guarded by curbings of con- crete a foot or more in height, laid out so as to form a narrow, curving passageway through which the vehicle must pass. Extension pieces on the end of the curb make it impossible for the car to straddle it. Drivers cannot go through this curving roadway at high speed, and so have no opportunity to take chances by rushing the gates or trying to beat a train to the crossing. Once across the tracks, the road is unrestricted, since such a device is equivalent to narrowing the road, and the idea is to make the crossing safe with as little impediment as possible. Windshield Gives Comfort on Deck of Bus INDSHIELDS on the upper deck of the city buses of Detroit, Mich., afford comfort to passengers traveling in the open air during chilly weather. The shield acts like the curved “‘dodgers”’ on the bridge of a torpedo boat destroyer, throw- ing the current of air over the heads of the passengers. The top seats are said to be nearly as warm as the interior. The shields can be removed with little diffi- culty for the hot weather. ECHANICAL smokers that inhale "4 four cigars at once are part of the testing equipment used by the cigar manufacturer to insure that your cigar shall, burn evenly. The manner in which various kinds of tobacco will © burn when they are actually being smoked, and the effect of various blends, are being tested in this way by David E. Brown, of the Department of Agri- culture. An air pump with an arrangement of valves produces intermittently a slight vacuum in a glass bottle to which the four cigars are attached, so that they are smoked in slow, gentle puffs. The time required to consume them is carefully Mechanical Smoker Tests Quality of Cigars noted. If necessary, the products of com- bustion can be absorbed in the water bot- tle, and the cigar analyzed. Your Bicycle Can Generate Current for Lamp OU can make a dynamo of the front wheel of your bicycle, and light the head lamp with the current produced, by means of a new device that is rapidly be- coming popular in Europe. A small electric generator is attached to the front fork, with a driving shaft ending in a rubber disk resting against the side of the front tire. Friction is extremely light, and the cyclist, it is claimed, does not notice the resistance in pedaling, yet the current generated is more than sufficient to light a Attached to the front fork, the tiny generator is driven by the tire flashlight bulb. The more complete outfits include a tiny storage battery, so that a reserve of current is available to light the wheel when it is standing still. During the day the dynamo is thrown out of action by turning it upward on a pivot, thus moving the disk out of contact with the wheel. VEGETABLE fiber manufactured from a va- riety of grass grown in China is soon to be used to add life to woven fabrics. The fiber can be mixed with cotton, wool, or silk. Damalar Serenro Manthli.

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July, 1922 The Future Airliner = Pictured by die Rickenbacker Captain Eddie Rickenbacker, who sponsors the design © Popular Science Publishing Co., Inc. HE commercial airliner of the future will probably resemble closely the airplane pictured here, especially if intended for supermarine travel,’’ writes Captain rsh Rickenbacker, first American ace during the war and now head of his own motor-car company. ‘*Radical as the design may seem, it will be observed that in its essentials—in cantilever wings; hull profile, retractable chassis—the airplane is simply an embodim at of engineer- ing practices already sanctioned in America and abroad.”’ This superliner of the skies, for passen- ger and freight transportation, which Captain Rickenbacker predicts will be realized “with the passing of but a very few years,” will be a giant monoplane, perhaps 300 feet from wing tip to wing tip. Have You Considered Aviation as a Career? By Glenn H. Curtiss America’s Foremost Airplane Manufacturer The motors will be of approximately 1000 horsepower each, several motors to a unit, and each unit driving a great propeller with three blades from 15 to 20 feet long. The motor units will be set in the wings, which will be very thick—from five to 10 feet on adventurous career. But remember that while commercial flying has been suffering depression recently, just like all other businesses, the leading aeronautical com- panies expect an inevitable HERE are the young men who are going to make brilliant aerial careers for themselves in the next few years? Whose will be the names written large on the sky, in terms of fame and financial success, when the great boom of commercial flying comes? Will you be among them? You may not realize how en- ticing a future aviation holds for the young fellow today expansion within three years. And when it comes, the great- est need will be, not for planes, routes, or landing fields, but for trained men. Boys now in high school and college will become the pilots and me- chanics, and when the ex- panding industry requires executives and salesmen, they will be drawn from the prac- tical fliers and mechanics, who know the business of looking about for an active, Glenn H. Curtiss aviation from the air down. Top—lInterior of, the airliner, showing motorsin wing. Above— Arrangement of cabins, state- rooms, pilot house and observa- tion deck in the nose the leading edge—and will be of intern- ally braced cantilever construction. The fuselage will be in the form of a boat, but landing wheels that draw into the body during flight will also be provided. This will enable it to alight on land and water. If you are looking about you for an occu- pation, the profession of aviation offers opportunities that seem almost unlimited. Up to the present time most of the men employed by the commercial aircraft com- panies were aviators trained in the war; but war training is becoming less necessary and less desirable. At the front, the successful pilot was the man who took the most risks. If he broke his plane, the army gave him another. Because it was necessary to take many chances, a war-trained pilot has a tendency to believe that a certain amount of stunt flying is part of a good pilot’s job. The commercial companies think differ- ently. Nowadays, a pilot who does reck- less stunts is warned the first time and fired the second; for, above everything else, profitable operation demands men trained

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36 to fly their machines safely —men who know that slight accidents that prevent a plane from going out on schedule cost money, and who are so thoroughly trained that they can avoid accidents and make the necessary repairs themselves. Many of the war-trained pilots meet these qualifications, but many more do not, and the largest flying companies prefer to train their own men. Moreover, flying is a young man’s game, and the former aviators are getting older. They are working in other professions, and however much they might like to do so, they are unlikely to return to aviation when the boom comes. The man who decides to go into aviation today has his choice of more than 57 trades and pro- fessions which it embraces; but although an expert in any occupa- tion from engineering to cabinet- making, from meteorology to bookkeeping, may find a job about a flying field, the profession of aviation divides itself into four main branches: - First there is manufacturing, both of planes and engines; second, operating by the pilots and mechanics; third, trans- portation, the selling of tickets and collec- tion of air freight; and, finally, the execu- tive, in charge of all. Just now, the chief shortage of men is in the transportation branch. Some of the most famous pilots Popular Science Monthly * THE early age of 34, Grover C. Loening, America’s most successful young airplane designer, is president of his own aircraft manufacturing company and was recently awarded the Collier trophy for the greatest achievement in aviation in 1921—the perfection of a monoplane air-yacht -approved by the Underwriters’ Laboratories. He is a graduate of Columbia and holds Grover C. Loening and one of his flying boats Grover C. Loening, a Big Name in Aviation at the Age of Thirty-Four the first degree ever awarded in this country for the technical study of flying. Loening’s career in aviation began as assistant to Orville Wright. Later he was Chief Aeronautical ‘Engineer of the United States Army, where his experience and initiative enabled him to develop many new designs for war planes. He prepared the standard textbook on mili- tary aviation. Young Loening originated the monoplane flying boat, invented the first rigid monoplane bracing, and in- troduced steel construction into airplanes in 1916. Among the outward signs of his success is his recent election as first president of the newly formed Aero- nautical Chamber of Com- merce. He says: “I do not see how any young man who decides to make aeronautics his life work can ever regret it.” This Teacher Found His Fortune in Flying we Ralph C. Diggins, a young school teacher, decided in 1911 to learn to fly, he spent six months and $800 in a “flying school’’ without getting off the ground. So he determined that the only way to fly at that time was to make his own machine and fly it. With the help of a friend he put together a conglomeration of wires, linen, wood and metal—and a motor, and after about three months’ practice he finally was able to stay in the air about 10 minutes at one time without the motor going bad. Those wild 10-minute flights led to exhibition contracts in 1912 and started him on a career in aviation. Today he is making money and success as one of America’s foremost aviation instructors and active head of a successful aviation school in Chicago, which trained 73 students in 1921, with a record of 15,000 flights for a distance of 70,000 miles. The same determination with which he built his first crude plane carried him through the pioneer days, through distin- guished overseas service during the war, and now is responsible for the en- largement of his school, established in 1919, to train 250 young fliers this year. His commercial flying activities today include an aerial photographic de- partment. During the past year he and his students have taken at least 2000 aerial photo- graphs. Diggins’ first commer- cial contract, on March 7, 1919, called for the delivery of a washing mact ine from Chicago to a home in Evanston, Ill. This is said to have been the first strictly com- mercial airplane flight in America. in the country—Roland Rolfs, for one— have become traffic managers, in charge of branch offices whose duty it is to sell air- planes and interest the public in airplane travel. But whatever line you may eventu- ally decide, upon, airplane operating is the essential groundwork. As in any other business, a man must learn aviation thoroughly if he is to be successful in any one of its branches. Aviation is still so young that even the highest executive must know how to fly a plane in order to manage the business and to interest other men in it. Here lies the opportunity for the young man of today. Many executives and salesmen will be needed before long. They will be drawn from among pilots and mechanics. The industry is growing so fast that there are practically no limits to what a person with the necessary preliminary technical training may accomplish when the expansion comes. The chances seem better than ever that the history of the automobile industry will be repeated upon a somewhat smaller scale. The mechanic of the early pioneer days will = the leader of the industry 15 or 20 years ater. Even after you have decided to learn -to operate a plane, however, there are still two ways of going about it. At present, while the depression still exists in the manufacturing plants, probably the best way is to go to one of the good aviation schools maintained by commercial flying companies. The course lasts from three to four months, and at its completion the student is graduated with a pilot’s flying license. The tuition is between $350 and $500. These schools are modeled after the army training schools. The course is thorough and intensive. While the details vary under differ- ent instructors, the student usually spends the first two weéks in the motor shop, where he sees the en- gines as they are made, and learns to recognize the parts. The next two weeks are passed in the manu- facturing shed, where he makes the parts of the wings and fuselage, learns how the plane is constructed, and becomes familiar with a complicated nomenclature. Beginning the second month, the student goes to the motor assembly shop. Here he learns the assembly, makes block tests and trial runs, and becomes able to operate an engine at its greatest efficiency. From there he goes to the plane assembly shed, where he assembles the plane, learns to wire it, to true the wings and to make the im- portant inspections that can be trusted to no one but the pilot. . The final week is spent with the shop in- spector, and is a review of the preceding two a Eddie Stinson Started in the ‘‘Gipsy’’ Game WENTY - SIX hours, 19 min- utes, and 35 sec- onds in the air! That’s the world’s endur- ance record for aircraft, set by Eddie Stinson , a and his partner, q . = "* Lloyd Bertaud, at Roosevelt Field, Long Island, N. Y., on December 29, 1921. Stinson’s career as a commercial aviator is one striking example of the fame that a good pilot can achieve in cross country flying if he seizes the op- portunities that are opening wider daily. While he was still in his teens Stinson read all the information published on air- planes, and then persuaded a friend to buy him a plane. He was confident, he said, that he could fly it. Notwithstand- ing his native flying ability, he crashed. Then he entered an aviation school. Before the war he was engaged in “gipsy flying,” taking up passengers for short flights in his own plane. He entered the Aviation Service in 1917. As flying instructor, he trained hundreds of war pilots, chiefly at Kelly Field. His next job was test pilot for the JL Airplane Company and it was in one of their ma- chines that he achieved the world’s en- durance record. He writes: ‘‘The next generation will know as much about flying as we do about the automobile. Almost any one can learn to fly if he has confidence in himself and the hardiness to undertake the necessary training.” © Povnular Science Month Jul grou the : theo! time place unle: age min¢ busi eigh with trol, “joy alwe case _ _—, ae ae ee | ee, oe SS a eT

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“BIGHTEEN years ago fly- ing was classed with perpetual motion. Who, then, will attempt to predict what airplanes can do 18 years in the future?”’ —Orville Wright. months’ work. This completes the ground school. During the evenings the student has been studying the theory of aviation. There is no spare time. A ground school is a very busy place, for the instructors assume that unless a student is far above the aver- age both in quickness, alertness of mind and bodily strength, he has no business trying to become an aviator. The flying course consists of from eight to 10 hours in the air daily, with an instructor, using dual con- trol, in which the student handles the “joystick,” with the instructor always at his elbow to take charge in case the novice starts to go into a tail- spin or a nose dive. The finishing course is “solo” work, where the student flies alone, and learns to make landings and to handle his machine until he is able to pass the pilot’s examination. Although there is no national license bureau for airplane pilots, the large com- panies have their own standards, and Courtesy Aeromarine Airways, Inc. “COMMERCIAL airplane service will become as much a part of our indus- trial life as railroad trans- portation is today.”’ —Glenn L. Martin. maintain them rigidly. It is clear that under this system a man may become a pilot in from three to four months. His salary, when the demand for commercial fliers devel- ops, may be expected to range from $2500 to a maximum of $5000, or, in exceptional cases, $8000 a year. But a pilot’s license will be the beginning, rather than the goal, of the successful aviator. It resembles a college de- gree. Though it means nothing in itself, it is a starting point for almost any position in the field. Training is more important than Learning to fly, the student handles the controls with the instructor always at his elbow wages during the first two years, for it should be emphasized that, in the How Glenn H. Curtiss Won Financial Success in the Air TS one outstanding financial success in American aviation is that of Glenn H. Curtiss, author of the above article. Not so many years ago, he was a young bicycle repair man with only a public school education, received in his home town, Hammondsport, N. Y. But inven- tive and mechanical ability and grit were among his gifts. Later, he built motors and established the world’s motorcycle speed record. Today, he is the most brilliant living example of thé subject he writes about in this issue of POPULAR SCIENCE MONTHLY — ‘Success in Aviation.” single cylinder motorcycles, covering a mile in 56 2/5 seconds. Then with an eight-cylinder cycle, at Ormond Beach, Fla., he rode a mile in 26 2/5 seconds, or 137 miles an hour—a record never equalled. To manufacture and sell Curtiss motor- cycles the G. H. Curtiss Manufacturing Com-~- pany was incorporated in 1905. Two years later Dr. Alexander Graham Bell, attracted by Curtiss’ knowledge of aeronautical motor design, called him in as director of experi- ments for the Aerial Experiment Association. Here he conducted glider experiments, de- Fame, fortune and leisure are his— all the result of hitching his career to the airplane, and hanging on. The Boy Mechanic Curtiss was born at Hammonds- port May 21, 1878, with a fondness for mechanics and a love of speed — qualities that have grown with him, bringing him 21 prizes and medals and 67 patents. As a small boy he amazed grown-ups with his ingeni- ous and often outlandish contriv- ances manufactured from old tomato cans, odd wires, and bits of machin- ery; in fact, he tried to make some- thing out of nearly everything that came his way. At the death of his father he be- came an apprentice with the East- man Kodak Company at Rochester, N. Y. Here, while working with wood and small metal parts, he acquired a knowledge that aided him later in building motors and airplanes. During spare hours he earned extra cash for his experiments and a reputation for speed as a Western Union messenger and in this capacity he broke all records for speed in delivering messages. He is said to have been the first person to use roller skates and the bicycle for business purposes. Returning later to Hammondsport, he worked in a small bicycle-repair shop, of which he finally became part owner. Meanwhile he experimented with motors and produced a motorcycle that made him famous. Riding at Providence, R. I., in 1906, he established a world’s record for . _ ay A cys : SAS oy " oe e The pioneer amon seated in one o f ioneer air adventurers is earliest biplanes signed new planes, built the first Vee type air- and water-cooled motors, and developed the aileron system of control. So rapid was his progress that, nine months after the organiza- tion of the association, Curtiss, piloting the historic “June Bug,” July 4, 1908, won a trophy for a flight of one kilometer -straight- away. In 1909 Curtiss began the manufacture of airplanes at Hammondsport, producing the machine which became famous as the “Cur- tiss type of airplane.” In one of these ma- chines he won the Gordon Bennett interna- tional speed event at Rheims, France, and gained international fame. Returning to America he perfected a suc- cessful engine for dirigibles, and’ with Captain Thomas S. Baldwin received the contract for the first United States Army dirigible. To meet an increasing demand for flying instruction he next organized the Curtiss Exhibition Company, and for several years gave personal flying instruction. One of Curtiss’ triumphs came with his spectacular two-stop flight down the Hudson River, May 29, 1910, in which he covered 150 miles in two hours, 51 minutes, and won a $10,000 prize. The next year he invented the first hydro-airplane, and in 1912 the first flying boat. Meanwhile he accomplished the first flight from land to water and from water to land at San Diego,‘Feb. 23, 1911. Following the formation of the Curtiss Motor Company he was commissioned in 1913 by Rodman transatlantic flying boat. This boat was partially completed when the war began in 1914, but the trans- atlantic flight was abandoned. His War Record The Curtiss Aeroplane and Motor Corporation was organized in 1916 with $9,000,000 capital. This com- pany eventually included nine plants and five flying stations. With America’s entry into the war larger plants were added. The number of different models of airplanes, sea- planes, and flying boats designed by Curtiss and his associates reached 200. In all, 7079 planes and 5292 motors were built by the Curtiss organiza- tion during the war. When the war. ended, Curtiss concen- trated his attention on his plant at Garden City, Long Island, where he built the NC transatlantic boats and new machines of the commercial type, including the Curtiss Oriole, Curtiss Seagull, Curtiss Eagle, the 10-passenger plane, and the Wasp, which formerly held the world’s altitude record. Other special designs for commercial and mail service are now being developed at Garden City, where Curtiss, as fond of mechanics and speed as he was in boyhood, is still active in designing and developing new types of craft for future air commerce. A new model, on the average, every six weeks—that’s the Curtiss idea of speed. Wanamaker to construct the first’ pinay na ne Tn rn a a age naan a apace amma nn

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33 opinion of leading airmen, aviation is a profession which should be undertaken in the same spirit as that in which a man sets out to learn medicine or the law. These experts declare that four years is not too long to spend in learning to be an aviator. When manufacturing conditions improve, the pilot who has obtained his training in the shops and by long commercial experi- ence will probably gain the best positions in the profession. Some young fellows who have sought the best possible training in aviation, without cost to themselves, have found jobs in an airplane factory. The me- chanic’s apprentice or a shop helper in such a fac- tory receives as thorough training in mechanics as if he were an apprentice to a machinist. The wages, nat- urally, are low—from $12 to $15 a week. The work con- sists of overhauling motors, be and being generally useful ( about the shop. The ap- ’ prenticeship lasts not more ' than two years, leading to work as a_ full-fledged “ground mechanic,” earn- ing from 70 to 80 cents an hour—the same wages as a machinist. The alert and capable man may soon advance from this stage to the posi- tion of flying mechanic, accompanying the pilot on his regular commercial runs. This is the best possible i way of learning to fly. You become assistant to the pilot. You help him make landings. You are responsible for the en- gines, and after 600 hours in the air, you become eligible for examination for a pilot’s license. On commercial routes, 600 flying hours can be piled up in less than a year, during which your wages as flying mechanic are at least $35 a week. A successful pilot earns from $50 a week up, in addition to his expenses; and after a few years’ flying ex- perience, with the growth of the game, he may become a salesman, a traffic manager, or an executive, with earnings dependent upon his ability. The wages in aviation compare favorably with those in other professions. The op- portunities, with the almost inevitable ex- pansion of the business close at hand, are incomparably greater than those of the mechanical or automotive trades; and yet after talking with pilots and executives now finding their career in the air, one finds that the romance of flying still seems to them its most desirable aspect. The aviator must be a man above the average. The lives of his passengers de- pend directly upon his skill. He must com- bine in his own person the functions and Popular Science Monthly yearly average of something like 9000 deaths in automobile accidents. While no pretence can make out flying as a wholly “safe” mode of travel, its com- parative safety is shown by the 1921 records of flying compiled by the Aeronautical Chamber of Commerce of America. Uncle Sam’s Expert Sees Need for New Pilots — almost out of sight, to a height of 40,800 feet, Lieut. J. A. Macready shattered the world’s altitude record Sept. 29, 1921. He is now chief test pilot at McCook Field, Dayton, Ohio, where he passes upon all new improvements, both of engine and plane, as they are submitted to Uncle Sam. Macready is con- fident that the indus- try that already has brought fame and success to himself, will offer like careers to others. “Even now,” he says, “there is an oppor- tunity for young men with technical and practical aviation knowledge, combined with inventive brains. I am firmly convinced that in time travel by air will be the fastest, cheapest, safest, and most pleasant means of transportation. “With the’ development of transportation lines and sys- tems, superintendents, man- agers, and presidents will be needed. Many profitable transportation routes are now available, and young men with brains and money are on needed to develop them.” Nearly half a million civilians, it is estimated, traveled 6,500,000 miles in 1200 aircraft engaged in civil flying in the United States. Yet during this period only 188 accidents occurred. There were 55 deaths in 33 of these accidents; 89 injuries in 42 of them, and in 48 accidents there were no cas- ualties. Forty-nine of the accidents were attributed to pilots, and 20 to inadequate landing fields or total lack of terminal facilities. Moreover, the one great commercial air transportation company now oper- ating in the United States has not had a fatal accident to passengers on its flying boats in two years’ flying history. In fact, one of the most encouraging signs that the day of profitable and reliable air lines—linking our cities with scheduled passenger, freight, and mail service—may not be far distant, is to be found in the report recently submitted to the Director of Naval Aviation by this company, owning the Aeromarine passenger planes. It oper- ates a daily mail and passenger service between Key West and Havana, Cuba, according to the report; also between Miami, Fla., and Bimini, and between Miami and Key West. Its fleet con- sists of six eleven-passenger converted navy flying cruisers and six five-pas- senger flying boats. In addition to abilities of a large crew. He must be engi- neer, pilot, and navigator. But the knowl- edge that he is master of the last realm to be conquered by man is a compensation for his difficult work. Aviation will never become huindrum or dull, and because it appeals to the imagina- tion, the man who combines a love of ad- venture with a natural aptitude for mechan- ics will be wise to look into the possibilities of finding a profitable career in the air. How Safe Is Flying? (Editor’s Note) 1 cig an airplane meets dis- aster, many people throw up their hands in horror at the “fatal riskiness” of aviation—forgetting, perhaps, our national Retriever Will Pick Up Your Golf Ball ‘TBE golf enthusiast may save energy for the next drive by the use of a new ‘ golf ball retriever, fastened to the putter handle, by which he can pick the ball out of the cup or from the green without stoop- ing. The novelty consists of a small nickel- plated brass cup the inside diameter of which is exactly the same as that of a golf ball. When the ball falls into the hole, the handle of the putter with the retriever in place is inserted, and pressed over the ball, which is caught in the cup and withdrawn. The inventor of the retriever claims that the extra weight at the end of the club will enable the player to putt more accurately. scheduled service, the company en- gages in special charter flights. The Aeromarine flying boats made 735 complete flights, the report points out, in the four months from November 15, 1921, to March 15, 1922, with a record of 640 hours flown, and 268,538 passenger miles. Of these flights, 171 were on the 100-mile Key West-Havana route, while the charter and miscellaneous flights totalled 359. During these operations, not a passenger nor employee was injured, and only five boats were forced to return to their bases. The schedules were maintained throughout, with the exception of these five flights, ac- cording to the report. In two years of operation, the report dis- closes, the company’s flying boats in passen- ger service have. flown a distance of more. than 150,000 miles, and have carried 10,700 passengers, without a mishap. Pocket Knife Carries an Outfit of Tools OW that a cork- screw on a pock- et knife serves only as a reminder of days gone forever, it has been replaced by a small monkey wrench that is a con- venience in working around an automo- bile. The new knife is large pocket size, and its outfit of tools in- pocket wrench, a heavy knife blade, a sc-ew- driver, and an arrangement to cut wire. July cludes, besides the = asce dan veh are wit’ loa ier the rut: chi: _ sere an jac the lift gro tra cy] rea

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July, 1922 Brass billets, after leaving the saw, are shown above on their way into the heating furnace of the extrusion ma- chine At the right is the extrusion machine in operation. The operator at the ex- treme left applies hydraulic plunger and ram against the end of the billet, thus forcing the bil- let through a die Huge Ram Squeezes Brass into Rods Great advances in the manufacture of brass rods have been attained with the use of an extrusion or “‘squeez- ing out” machine in which red hot billets, half .a foot in diameter, forced through a die by a ram, issue from the machine in the form of rods as thin as half an inch. At the left an operator is shown sawing the “gates” or jagged ends from billets - HYDRAULIC PLUNGER The rods are seen issuing from the front of the machine. The cylindrical cakes in the center foreground are unextruded ends of billets. The process is explained clearly in the cross section diagram at right HYDRAULIC PLUNGER Brass rods issuing from the die may be seen above. In the background is the mouth of the fur- nace. After the plunger has com- pleted its stroke, the unextruded por- tion of the billet is withdrawn and sev- ered from the rod RAM ‘RED-HOT BILLET Weighing Jacks Protect Highways from Overloaded Trucks yee jacks with which the load pressure gages. If the truck is found to 40 pounds each, so that the inspectors can carried by a heavy truck may be weigh more than 10 tons, the excess ma- carry them about in a light car. ascertained by road police are helping terial is unloaded by the roadside. The State officials estimate that this super- Maryland protect its new state roads from jacks are of aluminum alloy, weighing only vision reduced overloading 75 per cent damage by overweight vehicles. Most roads are constructed to withstand a moving load of 10 tons. Heav- ier loads break down the subgrade and start ruts, the police assert. Each weighing ma- chine consists of a screwjack operating in an oil-filled cylinder. When four of these jacks are placed under the suspected truck, lifting it clear of the ground, its weight is transferred to the oil cylinders and can be read directly on the Four screwjacks, operating in oil-filled cylinders, lift the suspected truck clear of the ground. The weight is then read on pressure gages within 30 days. Cali- fornia has also recently passed a law limiting the weight of motor trucks, and road offi- cials and taxpayers are seeking to reduce the maximum permissible weight below the limit now set — 30,000 pounds gross weight for four wheeled trucks, and 40,000 pounds for six wheeled vehicles, providing the axles are at least 96 inches apart, and there are not more than 800 pounds on each inch of rubber tire width.

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ee ee ae See RRL TATT TRe RT 40 Smallest Model Ship Is Fully Equipped NLY a crew of ants could find deck room in the model of the clipper ship Ariel, constructed by J. A. Bellhouse, of Medford, Mass., and said to be the smallest accurate ship model on record. Although but 51% inches in length, the model is completely fitted with gear and rigging, constructed exactly to scale, and is a masterpiece of microscopic craftsman- ship. The smallness of the perfectly propor- tioned ship may be realized by the fact that the transverse ‘‘timber’”’ in the foreground of the photograph, joining the two up- rights of the cradle, was fashioned from an ordinary toothpick. Each crosspiece is fastened to the masts by fine wires passing through holes pierced by a drill of hairlike fineness, and each rat- line of the shrouds is a single horsehair. The blocks are the tiniest beads the maker could buy. The model can be held in the palm of one hand. The detailed dimensions are: length over all, 514 inches; length of hull, 4 inches; beam, 1 1/16 inches; depth, 4% inch; height of mainmast, 314 inches; length of mainyard, 21% inches. Seed Threshed from Cones to Build New Forests — for planting pine forests in cqn- nection with the Federal reforestation program is gathered by robbing squirrels of the hoard of pine cones collected for winter food, and threshing the cones in homemade churns. The forest rangers first allow the cones to dry thoroughly in the sun and then throw them into a framework covered with a galvanized wire cloth. The box is then rotated with a hand crank. As the cones are tossed about, the friction and jolting As the dried cones are shaken, the seeds fall through wire mesh loosen the seeds, which fall through the wire- mesh to a cloth spread under the churn. About 50,000 pounds of valuable seed were recovered last year in this manner— enough to set out 50,000,000 trees. About 8,000,000 acres in our national forests are now being reforested with seedling pine. The Editor will be glad to supply the names and addresses of manufactur- ers cf devices mentioned in this issue Semi-Overalls Protect the Trouser Legs SEMI-OVERALLS, or protectors for the lower half of the trouser legs, have re- cently been invented by Edward L. Rich- ardson, of Brooklyn, N. Y., for use by those who wear dusters to protect their clothes. The protectors are suspended by straps from the belt and, fitting loosely, will not wrinkle the trousers. ' id Popular Science Monthly ~ Radio Doctor Gives First Aid at Sea _ goreegieng~ on vessels at sea any- where near New York City may now receive free medical advice by radio. A wireless dispensary is available every hour of the day and night. Last year more than 50 cases were treated in this way. Although most seagoing vessels are equipped with radio, about 80 per cent have no doctors aboard, and thus a popula- tion equal to that of a small city is con- stantly afloat within radio distance of New York without medical attention. The radio dispensary operating from New York is the first of its kind. The work is directed by the Seamen’s Aid Society, which receives calls and dispenses medical advice over a range equal to half the width of the Atlantic. An alert watch is maintained day and night by radio men in the receiving station in the tower of the Seamen’s Institute. Arrangements have been made with physicians so that at whatever hour the call is picked up, a doctor will be instantly available. These calls take precedence over all others, except the “SOS.” When Delay Is Dangerous Since most ships carry well stocked medicine chests and first aid supplies, the radio doctor is able to work with efficient tools. The’ ailments most frequently brought to the radio doctor are appendi- citis and ptomaine poisoning, both cases in which delays are dangerous. The radio doctor is able to get the temperature and pulse of the patient, prescribe medicines and direct the handling of the treatment effectively. In case of an accident, such as a bad fall from the rigging, he can give directions for first aid treatment. A hit or miss call for medical assistance is likely to result in- the loss of valuable time; this new service will do away with that possibility. Gaging Machine Records Depth of Oil Wells ‘THE depth of an oil well can now be ascertained accurately at any moment by asimple gaging machine recently de- signed by C. E. Van Ostrand, of the United States Geological Survey. The apparatus consists of a wheel mounted between two parallel bars that. hold it over the opening of the oil-well casing. The sand line is clutched against this wheel by two idlers. Coilsprings reg- ulate the tension. The depth is recorded in feet by use of a, revolution counter. This instrument has verified the assertion that the deepest oil well in the United States is the 7579-foot hole in the town of Fairment, W. Va. "July possib conto ditch, tainsi of incl witho' try. Ins' conto locati elevat in the tion made meth point sterec reselr ment the “* auto; The line : scop’ and ° Phot to hb angl alike The the base This abo map wou and fron ster

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S ie. FM ct | _ ns i cel A ood | ct @D oo wn Ww i I ME i, i July, 1922 Mechanical Surveying Machine Maps Hillsides and Valleys Like a Giant Tracing the Landscape and drafting machine based on the principle of the stereoscope, it is now possible to make an accurate surveyor’s contour map mechanically, plotting every ditch, hillock, and tree stump on a moun- tainside several miles away to an accuracy of inches—and this without calculation and without sending a surveyor over the coun- try. Instead of the usual method of drawing contour lines by interpolation—that is, locating a few important points of equal elevation by triangulation, then drawing in the remaining points of the same-eleva- tion by guesswork from rough sketches made by a surveyor in the field—the new method locates exactly each individual point with the aid of photographs, the stereoscope, and a complicated mechanism resembling a pantograph. The new instru- ments are called the ‘“‘photo theodolite’”’ and the ‘‘stereoautograph.”’ How Photographs Are Taken In the field, the first step in this stereo- autographic method is to choose a baseline. The camera is set up at each end of this line and oriented with a theodolite—a tele- scopic device for measuring horizontal and vertical angles—placed above the lens. Photographs are then taken of the country to be mapped, each at certain definite angles to the baseline, which angles are alike for the plates taken from each station. The height of the stations is ascertained by the usual methods, and the length of the baseline measured photogrammatically. This ends the field work. It has taken about two hours, and in 10 hours more the map can be drawn—an operation that would require several days of calculation and plotting by former methods. Two plates, one from the left and one from the right station, are now placed in a stereoscope, mounted on the frame of a B: MEANS of a newly invented camera

At each end of a known baseline, , photographs of the country to be ..mapped are taken with this camera

complicated drafting machine. The ma- chine is adjusted so that when the surveyor looks through the eyepieces, his right eye sees the country as photographed from the right station, while his left eye sees it as taken from the left station. Thanks to the stereoscopic principle, the country is seen in perspective in three dimensions, and not flat like a photograph. Within the field of view appears a little black arrow. This is a marker, or ‘“‘wander- ing point” which, by adjusting the appa-

With the machine method, the sur- veyor is like a giant moving the point of his pencil in horizontal plaries over actual country

PANTOGRAPHS

PEN DRAWING ON MAP”

HILL TOP 160

ratus, can be set at any desired height. Suppose the surveyor took his pictures at 100 feet above sea level and wished to draw a 110-foot contour line. He adjusts the machine until the marker stands at this elevation. Thereafter, wherever the wan- dering marker goes horizontally, it will always be 110 feet above sea level. Machine Draws Contour Lines Accordingly the surveyor moves this arrow across the picture, always keeping its ‘feet’ in contact with the ground. As he does so, a complicated arrangement, somewhat like a pantograph, draws a con- tour line upon the map to any scale desired. It is exactly as if the surveyor were a giant, with his eyes as far apart as the length of the baseline, and a pencil in his hand, the point of which always moved in a horizontal plane of known height. If the giant moved this over the actual country, he would determine points of equal elevation, thus tracing a contour line. The lenses and gears of the new instru- ment enable the surveyor to do the same thing. As the pictures are taken at a known angle from a known base, every point in them is really located by triangu- lation. BASE-LINE DISTANCE SET ON THIS SCALE

. +e LEFT STATION NEGATIVE, =‘ ?

Looking through the eyepieces of a stereoscope mounted on a compli- cated drafting machine, the surveyor sees the country in true perspective. He then adjusts the machine until a black marker in the field of vision is fixed at a given elevation. As he moves this marker over the ground in the picture, a pantographlike mechanism draws a contour line on the map to any desired scale, as shown on the left

Wonders Performed at High Pressure UEEZING mild steel into the cracks and folds of a soft rubber washer, as into a die, deforming steel bars with an ordinary paraffin wax candle, and com- pressing water to 20 per cent of its original volume are some of the physical marvels possible at a pressure of 300,000 pounds a square inch, reports Mr. P. W. Bridgman, of Harvard University. Under pressures of from 12,000 to 20,000 atmospheres, the character of many com- mon substances alters completely. Hy- drogen gas, for example, will force its way through the pores of a thick steel bottle, and eventually will make a crack that can be seen with the naked eye. Hot liquids can be frozen by the applica- tion of pressure alone. At 300,000 pounds pressure, water will turn to ice, though a thermometer may show itis at 180° F. The first effect of pressure on ice is to lower the freezing point, but if the force is increased, a strange collapse comes at 2000 atmospheres. ‘The force that holds the molecules apart is overcome, and the ice shrinks 18 per cent in volume. It will then sink in water instead of floating.

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42 Popular Science Monthly” 1A CHEESE FACTOory 35 MILK USED — 255036 “ NCLE” Horace Rees, of Low- ville, N. Y., dean of American cheesemakers, recently celebrated his eighty-first birthday by pouring the largest cheese ever manufactured. It is a monster, standing over six feet high, and weighing slightly over 12 tons—enough, it is computed, to make 300,000 sandwiches. , It is extremely difficult to make such a cheese, not only because of the size, but because milk from many different dairies must be treated in exactly the same way. Twenty-one dairies contributed to the making of this world’s record. Several had to save two days’ supply of milk, for 125 tons of milk were used. This supply represented a day’s output for more than 10,000 cows. The cheese was made for exhibition at the State Fair. Largest Cheese Weighs 12 Tons HEESE EVER MADE Boxe I FROM 10200 cows HELSI 24289 LBs Tractor Is Mechanical Loader Pavement Is Billboard Cie streets and sidewalks may be con- verted into temporary billboards by an invention resembling a lawnroller that prints the advertising message in water on the asphalt. As the machine is pushed along by its operator, a spray of water from the tank in the upper half passes through a perforated belt or drum that acts as a stencil. The belt is of fine wire gauze with waterproof letters fastened upon it. In consequence it leaves.a band of wet, dark pavement behind it, upon which the words of the advertisement stand out—dry and white, as shown in the illustration below. Pogo Sticks Invented to Hop across Stream OGO sticks were invented about 300 years ago by a blacksmith in a Tran- sylvanian village who wanted to keep his feet dry, according to Mr. G. Pilarcezyk, of New York City. His account is as follows: Pogo was originally the name of a small Transylvanian village on the bank of a stream, across which lay the cattle pastures. A series of rock piles was placed in the stream so that an active man might cross by leaping from one pile to the next. In the seventeenth century, a wandering mechanic invented the first rude pogo stick to enable any one in the village to hop from one rock pile to another. J V/V BESEVER there is a job of heavy shoveling, the mechan- ical loader, invented by A. H. Less- man, of Des Moines, Ia., does the work with the power derived from a small tractor. The driver, sitting in the tractor seat, controls the tractor by operating a single lever. The loader is supported by a strong frame of I beams and is raised and lowered by wire ropes running over pulleys from a small winch at- tached to the engine. Shoveling is accomplished by manipulating two lighter levers attached to the top of the shovel, which push the scoop forward as it drops to the bottom of the pile of material to be removed, or tilt it forward and downward after it has been raised over the tail of the wagon being loaded, thus allowing the material to slide out. Two Trees from One Trunk IN THE historic old churchyard of St. Mark’s in the Bouwerie, New York City, are two trees growing from one root, al- though they stand 20 feet apart. While endeavoring to reach one of the old burial vaults in the yard, the sexton discovered that when the roots of a very old tree expanded, they came in contact with the vault roofs and were unable to grow downward. Instead, they spread along the tops of the vaults and then ap- peared on the surface. At this point a second tree developed, which can be seen side the “mother” tree. ait | the right in the photograph below, be- July, How Siew pe self si stratec young who i readin chine-' she ti office 1 To uses t] writes raised gressit The writin instea embos Braill of pa) the bl notes write! The prints the ec Braill Cross soldi Ins collec

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ly "7 ]- July, 1922 How Blind Stenographer Takes Dictation HAT blindness does not bar the person thus afflicted from being self supporting has been demon- strated by Miss Grace Keator, a young blind woman of New Yok, who is shown above in her office, reading the raised characters of ma- chine-made stenographic notes which she transcribes on a conventional office typewriter. To take dictation Miss Keator uses the machine at her right, which writes stenographic characters in raised form on an automatically pro- gressing paper tape. The inset shows the new type- writing machine for the blind which instead of employing a reeled tape, embosses the letters and figures of the = = —" Ee j : Stal “IS : at fyi k- f wl Oe at | a Je — \) Rs = pata Thermometer Tubes Pass Rigid Inspection » hoe health may depend upon the skill with which inspectors of clinical thermometer tubes recognize microscopic defects in the glass. Thermometer “‘canes” are now tested for uniformity of bore, perfection of the magnifying effect of the rounded front of the tube, and for freedom from blister bubbles and other ex- terior defects. These tests are so rigid that 75 per cent of the material bought is rejected as unfit. The most important of the tests determines the size and uniformity of the bore. The hole in a thermom- eter tube is only eight ten thou- sandths of an inch in diameter—less than one twentieth the thickness of a hair. Upon the perfection of the bore Braille system in lines on a sheet of paper. From this embossed’ record the blind operator transcribes the dictated notes in ink-print on an ordinary type- writer. The characters that the new machine prints, or rather embosses, are formed of the combinations of the six points of the Braille system. Pitch Coins for Charity SSING away coins for charity has become a “rattling good game” since KE. Fred Cullen, a Boston business man, invented a money scoop for use by the Red Cross in collecting funds for disabled soldiers. Instead of handing your money to a collector, you toss it into the scoop. The rattle of the coin as it falls through the hollow tin handle draws the attention of passers-by to the appeal painted on the device. The handle also contains a slot for inserting dol- lar bills in case the donor does nottrust his throwing arm. iret WIN~ MOMEY GOE 5 701 é HELP THE DISABLED SOLDIERS pac wip tossed into this scoop rattles down the tin handle into a collec- tion box Skyscraper Lumber Piles GEYSCRAPER lumber piles that tower from 60 to 75 feet above the roadway are becoming common in the lumber yards of Puget Sound since the introduction of a mechanical stacker that works on the prin- ciple of a bucket loader. The planks are placed in brackets attached to an endless chain, lifted over the top of the tower and down the other side, where they are trans- ferred to the pile. The piles are sometimes from 80 to 95 feet high, resting on concrete sills sunk 20 feet below the level of the road, so that about 35 feet of the stack can be built by mechanical aid. Gold Film Is Transparent (5° 1/2,798,000 of an inch thick, or 10,584 times thinner than the ordi- nary sheet of printing paper has recently been produced. One grain of the precious metal of this thickness covers nearly four square feet of area and is perfectly trans- parent. The process of obtaining the thinnest film is to cut a sheet of copper to a -deter- mined size and place it in an electric bath, where sufficient gold is deposited on one surface of the plate, to produce the finest gold color discernible. To separate the film of gold from the copper, the gold- plated copper strip is immersed in a weak solution of nitric acid for several days. The copper is entirely dissolved, leaving the film of gold floating on the surface of the liquid. The film is then collected on a glass plate. depends the size of the bulb, which must be very large comparatively to produce a range of nearly 30 degrees on the short stem. The, bulb of a clinical ther- mometer usually has 1000 times the capacity of the bore. Portable ‘‘Bike’’ Folds Up Nee comes the portable bicycle to join the company of portable typewriters, sewing machines, phonographs, and ga- rages. The new invention was designed for the convenience of travelers and motorists, for use on tours and camping trips— wherever space is valuable. , Since the wheels are much smaller than those of the average bicycle for adults, and the frame is collapsible, the new “‘bike”’ can be folded into a compact bundle, and even packed into a trunk. Theframe is so constructed that it may be adjusted to fit adults or chil- dren. Tested by rid- ers in the recent six-day bicycle race in New York City, the “‘port- able” was found to be durable and speedy. How the port- able bicycle, with collapsi- ble frame is folded for packing

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SRNL A ae fh AS 44 the Missouri to OR 41 years engineers have battled Fk to bridle the turbulent Missouri River; yet each spring the unruly stream, roaring defiance to the mastery of man, has torn itself from its channels, plowed through fertile fields and de- stroyed bank protections designed to curb it. There have been times when the Iowa farmer, owner of rich acres on the river bank in January, has, in April, found himself the proprietor of worth- less stretches of sand in Missouri, half a mile from the river. But, at last, the “Big Muddy,” that for years has laughed at revetments and solid dams of concrete and steel, is being induced to control itself! The self- taming process is being accomplished by the use of a newly invented self-driving concrete pile that sinks deep into the soft river bed and becomes a secure anchor for mats of trees and brushwood to retard the stream. Behind these mats the Missouri deposits portions of its load of silt, quickly building under- water sandbars to deflect the current from its banks and hold it to its channel. To Save Rich Farmlands By the new “retard” method, engi- neers hope to save millions of acres of fertile land along the Missouri and the lower Mississippi from the danger of periodic inundation. The amount of dirt and sediment car- ried by a river depends upon the speed of the current. If you can slow up the stream by an obstruction, some of the dirt carried by the water will be dropped, the heaviest particles first. With a river like the Missouri, a sandbar grows up like magic behind any obstruction, affording the best possible protection to the banks behind it. Effective obstruc- tions could not be made with ordinary piles, for the ice carried them away. The new pile, however, buries itself under the river bottom, where the water can- -” 18 How the hollow concrete >, held verti- | cally by a crane, drives itsel Jets of water, spurting upward, prevent sediment from clinging to the sides, thus eliminating sur- face friction in the stream bed, a hose is connected with the four-inch inner pipe at the upper end, or head, of the pile. By means of a pump with a capacity of 1000 gallons a minute, water is forced into the pile at a pressure of 150 pounds a square inch. A powerful Popular Science M onthly | Teaching a Cranky River to Control Itself Retarding System, Based on Invention of Self-Sinking Pile, Forces Form Sand Bars and Protect Its Banks stream of water squirts from the two- inch opening at the point, and smaller a shoot upward from all the side jets. While the pile is held in a vertical] position by a derrick, the stream of water from the point bores its way into the soil and the pile sinks rapidly by its own weight. It would not sink far if it were not for the side jets. Meanwhile, water spurting from the side jets keeps sediment from clinging to the sides of the pile. This eliminates surface or “skin” friction. Thus the pile buries itself in about sever minutes. Mat of Trees Retards Current Four feet from the upper end, a dozen one-inch wire cables, each 200 feet long, lead from the anchored pile to which they are firmly fastened. While the pile is being driven, along the bank scores of small trees are cut and loaded on working scows. A wire cable is passed around the butt of each tree in a half hitch, and held by two heavy staples. In this manner a mat is formed of 25 or 30 trees. The barge is towed about 100 feet downstream from the pile, and there the mats are attached to the cables leading from the pile at the bottom of the stream, oné mat for each cable. For additional strength, a second cable goes from each mat to a strong post on shore. The trees are placed with their tops pointing downstream. The barge is then towed out from beneath the mats, and as soon as they strike the water,. the engineers’ workisdone. The river begins to ‘‘con- trol itself’’ at once. The force of the current causes the trees to settle to the bottom of the river. The masses of interlaced branches retard the current, and sand and silt are deposited on the river bottom behind the mat. As the current slackens, the mat lifts itself slightly from the bottom, and the sand- not loosen it. Within a few days or hours before a flood be- gins rafts of brushwood can be anchored at the danger points. Simple as it appears, the in- vention of the new pile brings into play a new adaptation of the science of hydraulics. The pile is a thick tube of reen- ~ forced concrete with a four- inch pipe running through its center, and a two-inch nozzle at the point of the pile. At intervals of from three to four feet half-inch holes are bored diagonally into the inner pipe, forming jets that point upward, away from the pile point. Each jet consists of an ordinary pipe ell, extending upward for a distance of about two inches. Jets are placed on all four sides of the pile, which is cast 52 feet long, 16 inches square, and contains about 2% cubic yards of concrete. In driving one of these piles Vast Farmlands Await Rescuers HEN at last our army engineers completely conquer the Mississippi River, an area said to be equal to the four states of Delaware, Connecticut, Rhode Island, and Massachusetts will be added to the productive farmland of the United States. The invention of a new concrete pile—almost sensational in its simplicity—that sinks itself deep into a river bed and forms the basis of a retarding system to make the stream protect its own banks, is already taming the hitherto untamed Missouri River. If it proves to be equally successful on the lower Mississippi, the lands recovered from swamp would be worth $1,600,000,000. They would support a population of ‘7,500,000. bar is thus gradually built up until it almost reaches the surface. Owing to their action upon the current of the river, the mats are called ‘‘retards.” The principle of the retard differs from that of masonry or concrete jetties, which di- vert the current of the stream and cause a swirling eddy near the jetty in which sand is de- posited. It also differs from “rip-rapping,” or covering the river banks with layers of stone or willow twigs in order to pre- vent the stream from eating the bank away. Both these forms of protection are liable to be carried away by ice. With the retard system the mats are gradually sanded in and are thus protected from ice packs, while the anchor pile that holds the retards in posi- tion is beneath the stream bed, out of reach of all possible July scou cable sand, In meth surve curre has b river down and i situat enco and, maki instea In other avera The | trees; H A tectic som, Here to th of w Vast prote was ¢ to th with and tecte sand next high curv 30 t tirel. acu mor has a fiv hoo the hou gine pipe ste spu

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es v0- ler ide cal ito en ig, ch ng ut ire ch vO at ge im. ire al July, 1922 scour. Incidentally, as both the trees and cables are always submerged and buried in sand, they are protected against decay. In protecting a river bank by this new method, the engineers first make a careful survey of the threatened area and chart the currents at and above the point where erosion has begun. The retards are placed where the river begins to bend, and from this point downstream they are placed at such angles and intervals as the needs of the particular situation demand, always with the idea of encouraging the maximum amount of silting, and, if possible, developing new land by making the river narrow, straight, and deep instead of broad, shallow, and winding. In some cases three retards are enough; other bends require as many as 14. The average retard contains about 1500 trees. The largest ever built consisted of 4000 trees; the smallest, 500. How a Railroad Was Protected A demonstration of the complete pro- tection afforded was recently given at Fol- som, Ia., a few miles below Council Bluffs. Here the main line of a railroad ran close to the river bank, and for years the right of way had constantly been menaced. Vast sums had been spent in emergency protection. In one case when the bank was about to cave in, a spur track was built to the river and a train of flat cars loaded with rock was backed into the river—cars and all. But this extreme measure pro- tected the bank only for a short time. As soon as three retards were placed, sanding-in began, and by the time of the next flood the new sandbars had grown so high that the channel in the horseshoe curve by the river at this spot, once from 30 to 60 feet deep, had become almost en- tirely filled. As a result, the river formed a cut-off that left the railroad right of way more than a mile from the new stream. > ee ne Who: CABLES SUBMERGED CONCRETE PILE Trees woven into a great mat and fastened by cables to concrete piles an- chored below the river bed form a ‘“‘retard’’ behind which a sandbar forms to deflect the current and throw it away from the bank RRENT DIRECTION OF CY de A typical retard, firmly anchored along the river bank, is shown above. river straightened its own channel after retards caused sandbars to form at a bend in the stream. Dot- ted arrows indicate the new channel It is the hope of engineers that this system, which has proved suc- cessful on the turbulent Missouri, can be generally applied to safeguard the 1200 miles of the lower Mississippi. The problem there is almost identical, atta rose 7 a CABLE TO PILE —_ i Ae fh The map at the right shows how the Yj and though the volume of water is great- er, the speed of the current is less. Attempts to control the Mississippi with levees above the water level have been only partially successful. In high water periods, as during the past spring, there is a constant menace of breaks in the levees, with sudden destructive floods. The new invention that makes the river control itself by building up sand bars below the water would not eliminate this recurring menace of high water, but might be expected to protect many million dollars’ worth of land. Two-Cylinder Steam Truck Proves Practical wee is said to be the first practical steam truck built in the United States has just made its appearance in a two and a five ton model. The fuel used is kerosene. A fire tube boiler is located under the hood, and the engine is geared directly to the rear axle; in fact, since the differential housing also forms the crankcase, the en- gine and rear axle are one unit. The steam pipes run from the boiler in the front to steam cylinders just in front of the rear axle. The usual bevel gears are eliminated. A spur gear on the crankshaft meshes directly with a spur gear on the driving shaft, for as the engine is a two-cylinder double-acting design with valves operated by eccentrics, quick and positive speed control can be ob- tained by the throttle alone. Steam trucks have proved successful and popular in England, where more than 10,000 are in operation at present. The development is ascribed to the excessive cost of gasoline. The advantages claimed for the new American truck are greate. simplicity, increased power, and the econ- omy of kerosene fuel. hy FIRE TUBE . BOT ER Engine and rear axle are one unit in this newl fire tube boiler is located u designed steam truck. The er the h It’s a Wise Man Who Knows His Umbrella MBRELLA tags, dis- playing the own- er’s name and ad- dress, that fasten firmly to the stick above the upper catch, and are protected from the rain by a thin sheet of celluloid, have been invented by E. L. Gaines, of Seattle, Wash. Many a man carries around a borrowed um- brella sincerely believing that he bought it him- self. But if he writes his name and address on the little tag, there is no longer any excuse for mistakes in ownership. SMALL metal weights that have become magnetized should be guarded against in making accurate scale tests, according to the United States Bureau of Standards. The Bureau suggests that all such weights be examined with a compass before use, otherwise serious errors may result.

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Re pee RO 46 WIRE ropes instead of steel beams were used recently in a novel tem- porary bridge of 110-foot span con- structed over the Kern River, Calif. The bridge is a rigid-deck truss, although four 114-inch wire cables act as its bot- tom chords. Construction was quick and easy, for the use of rope obviated the necessity of false work. The cost is said to have been only $2000. The use of rope instead of girders was possible only by seeing that all rope stresses were tension or pulling strains. In building the bridge, the four cables Wire Cables Act as Bridge Girders ota a NG were first anchored in place with great care that all sagged equally. Notched cross pieces were then placed upon them and very lightly spiked together. After all weights, even the living load of the carpenters, had been carefully balanced to avoid distorting the bridge, the braces were nailed firmly in place. Once tied, the entire span acts as a unit, and is as rigid as if it were built on a single steel girder. Even when a load is on the bridge there is no movement of its members as in the case of ordinary suspension bridges. “ENDLESS BELT PRINTING UNIT Fruit Stamping Machine Prints Grower’s Name A PRINTING press for lemons and oranges, that will imprint on the fruit itself the grower’s trademark, is the inven- tion of Fred J. Sevigne, of Milford, N. H. It can be utilized for marking any spherical or near spherical object, from baseballs to eggs. The fruit to be marked comes to the ma- chine resting in cups carried by an endless conveyor belt, and passes beneath a re- volving belt of soft rubber. This bears plates of the name and address of the grower, inked by a mechanism at the top of the machine. As the fruit comes into con- tact with a plate, an actuating device re- volves it against the stencil under pressure. Passing from the belt plate, the fruit is lifted from the cup by an automatic pro- jector and sent down a chute to the wrap- ping machine. Tracing Made Easy by Light under Board "aa ito up with the blueprint machine will be easier for drafts- men whose work is expedited by this elec- trically lighted tracer. An electric light located below the work shines through the paper, and a tracing may be made more quickly and far more accurately. The size illustrated is adapted to the reproduction of drawings on the sheets of a mimeograph- ing machine, but the device is valuable for any tracing work. 4“ % G4 comcre lanai An electric light shining through a glass from below simplifies tracing work Popular Science Monthly : New High Explosive Can Be Handled Safely B* SHOOTING bullets through a stick of high explosive held in the hand, H. P. Bostaph, of Detroit, Mich., proves that his new product may be roughly handled with impunity. While it has the power of dynamite when exploded with a detonator, the inventor claims that it can- not be exploded accidentally even if tossed into a fire or struck by a heavy hammer. Railroad statistics reveal that in trans. porting high explosives, 400 persons are killed and injured, and over $3,000,000 in property destroyed every year by acci- Bullets fired through this stick of high explosive fail to detonate it dental explosions. The formula of the new product would eliminate such accidents, it is claimed.. The composition is a slight variation of the TNT usedinthe war. Its qualities are said not to be affected by temperature or age. Improved Mounting Holds: Lathe Grinder Firm BoLtED upon the compound rest of a lathe instead of to the toolpost, a new universal lathe grinder is so mounted as to secure greater rigidity and to eliminate chattering. As the frame is of aluminum alloy, the weight is kept to 22 pounds without loss of mechanical efficiency. The grinder consists of a urfiversal elec- tric motor with a two-step pulley which permits a speed of 12,000 revolutions a minute on load. Tension of the driving belt is secured by sliding the motor in the slots of its base. A second slot one inch wide and three inches long, provides means of fastening the tool to the machine. WASTE from grape-juice factories may be utilized by manufacturing the steams into cream of tartar, the skins into jelly, and the seeds into oil, meal, and tannin extract. July

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July, 1922 Camera Checks the ‘‘Ump” when Fans Howl ee E’S—out!”” The runner may kick and the fans howl. The umpire has decided and that settles it. But was the runner really out? Until Arche M. Dunning, photographer, of Los Angeles, Calif., perfected a new method of photographing close plays, no one could say certainly whether the arbiter was right or wrong, unless a news photographer caught the play from close at hand. From a small platform on the roof of the grand stand, Dunning photographs with telescope lenses close plays anywhere on the diamond. The pictures of the plays, when finished, appear to be taken from a distance of a few feet and show in many cases whether the umpire was right or wrong. In one case, a game was lost because the umpire called a man out at first base. The ball beat the man to the bag, the umpire said. But when Dunning developed his photograph of the play, it showed the runner’s foot touch- ing the bag and the ball several inches away Armless Man Writes With a wooden disk tightly strapped against his chest, from which extends a wooden rod about a foot long, with.a clamp on the end for holding a pencil, this armless man _ soon learned to turn the pages of a book, to sketch, and to write legibly. Use of the device is being taught in the hospitals of London, England Let the Bottles Fly! To protect them- selves against stones, broken bot- tles, and other mis- siles hurled at them by rioters, Egyp- tian police are now equipped with small wicker shields. Front and back views of the shields are shown at the left. This light, tightly woven ar- mor is as effective in stopping ‘‘brick- bats” as is the steel armor worn by police in our large cities in stopping bullets Hospital for Buses At least 15 omnibuses are pulled apart and reassembled daily in the centralized motor-bus hospital of the London General Omnibus Company. The photograph below shows part of the standardized equipment for handling bus bodies—a body lift and electric truck Dogs Pay Their Income Tax Dogs that earn $100 a week appeared recently in person at the office of the Income Tax Collec- tor of New York City to swear to their returns. The canine plutocrats all gave their occu- pations as “‘actors.” Most highly paid dogs are in circuses, but some are in the movies. Two of these ‘‘actors’’ are said to draw salaries as high as $50 aday The Whirl of Fashion A new use for the electric fan—for hat trimming— has been discovered by Miss Ethel Beech at Miami, Fla. She electrified society there by appearing in a hat trimmed with clothespins, set off by a small electric fan and two dry cells, as pic- tured above

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sah ee RRS ee ne ny ; ee ee ee ee ee ae. 48 Simple Fuse to Safeguard High Voltage Circuit IGH tension fuses, resembling the simple device used on lighting circuits have recently been perfected for use on circuits carrying upward of 115,000 voits and 400 amperes. Tests on high voltage short circuits seem to prove these fuses act more rapidly than the oil circuit breaker usually employed. The fuse wire is fastened to a stretched spiral spring, which is released as the wire The high tension fuse before and after blowing ing on 66,000 volts melts. Instantly it contracts and draws the fuse wire to the bottom of the fuse, introducing a large gap. The whole fuse works in a non-inflammable liquid, which is directed into the gap as the parts draw apart, smothering the tendency to arc. The speed of operation is said to be less than 2/100 of a second, so that if an arc starts, it is soon checked. Steel TapeWinds Phonograph and Saves Work ATED by the drudgery of contin- ually winding his phonograph, Allen D. Bosworth of Brooklyn, New York, in- vented a steel tape which would replace the crank. He mounted a_ sprocket, about four inches in diameter on the end of the shaft, and passed steel tape about it. One pull of the steel tape equals four turns of a crank. Arrow indicates fuse blow- Popular Science Monthly ' , Hay for Cattle Sorted and Analyzed HAT baled hay can be scientifi- cally and quickly an- alyzed,to determine its food value before it is fed to live stock, has been proved by H. B. McClure, hay specialist of the De- partment of Agri- culture. His inven- tion- of a_ sorting table with six com- partments enables inspectors to separ- ate the various kinds ‘ of grass of which a SAMPL bale of hay is com- Seliencaure posed and to grade them, according to their amount of nu- tritive value. The hay is examined in a sliding sample tray with a wire mesh bottom placed on top of the desk, so that dirt and fine ma- terial sift through into a separate com- partment. The moisture content of the hay is determined by heating a sample in an electric oven placed close to the tables. In grading the hay, the inspector first examines the bale under a strong light to —————————— °C aa a pg - we. * COMPONENTS WEIGHED! TO FIX PERCENTAGES form an opinion of its quality as a whole. Weighed samples are then sorted on the table, where the percentage of weeds and inferior grasses, the color, texture, condi- tion, maturity, and excellence of curing are determined. A final value for the hay is based on all these factors. The government’s laboratory for hay standardization is at Alexandria, Virginia. Armless -Sharpshooter Uses Teeth to Win Matches [Ss of both arms has not prevented William A. Winemiller, of Spencer- ville, Ohio, from becoming a crack rifle shot, famous throughout northwestern Ohio as the “armless sharpshooter.” He has already won 10 consecutive shooting matches this year. Winemiller was a deer and bear hunter when a young man. Twelve years ago his right arm was severed near the shoulder, and his left arm between elbow and wrist. Now he uses a special rifle, very light in weight, which he balances on the stub of his left forearm. He fires the rifle with his teeth by means of a small wire leading from the trigger to a rubber plug held in his mouth. In his last match a 50-cent piece would cover the holes made by 10 shots fired at 50 yards. Automobiles on the Farm BYERY third farm in the United States has at least one automobile; but only one farm in 28 has a tractor, and only one in 50 a truck. Since only 40 per cent of farms have telephone connections, the auto seems the most deSired adjunct to rural life. Even now only one farm in 10 has water piped into the house, according to the report of the United States Census Bureau. ‘‘A Motorcycle for Cost and an Auto for Comfort’’ Cpe pees to be “‘a motorcycle for cost and an automobile for comfort,”’ a new vehicle combines the two wheels and han- dlebars of the former with the chassis and spring suspension of the latter. The result is a light, fast means of motor transport for one person. The front axle, shaped like an arch, does away with danger of breakage by applying the thrust load on the center line. This feature enabled the designer to build the front fender broad enough to keep wind and dust off the rider. The rest of the chassis is exactly like that of a tiny automobile, with all machinery * ERICIIONDRIVE — CHASSIS SPRING aaa AND STEERING. CONNECTION Automobile-like chassis, spring sus- pension, and enclosed machinery are shown in the motorcycle above enclosed. With the center of gravity below the hubs of the wheels, the vehicle can be kept upright more easily, it is said, than the average motorcycle. The chain drive and methods of manual control have been adopted from the motorcycle. July, A N m winds around protect consist frame along a rota that Ww! the tw! rate of ute. T 12 expe do an job. The fed by gers fi rotatin center and di drive f tric m carrie¢ winde! frame moto hangs cable. rollers necess

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— Sewo | >

July, 1922 Electric Winder Binds Wire ‘Cable A NEW electrical machine that winds tarred twine around wire cables to protect them from rust consists of a movable frame that pulls itself along the cable, and a rotating mechanism that winds, or “serves,” the twine tightly at the rate of three feet a min- ute. This is faster than 12 experienced men can do an equally perfect job. The tarred twine is fed by four steel fin- gers from a reel toa rotating winding head centered on the cable and driven by a chain drive from asmall elec- tric motor. The reelis carried around with the winder, but the steel frame supporting the motor and switch hangs steadily from the cable. Springs on the rollers feeding the twine keep it at the necessary constant tension. Machines of

ry MPREEL CARRYING P<?) edpas Benes : \ COVERED. off

% FEEDING MECHANISM REVOLVES IN ‘ CLOCKWISE DIRECTION * PROPELLING MOTC Pulling itself along the cable, the mechanism described in the inset winds the twine at the rate of three feet a minute this sort are now in use in the Navy Yard at Puget Sound, Wash.

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Electric Phonograph Music for Broadcasting FLLECTRICAL reproduction of phono- graph records by a device that elimi- nates the horn and gives the listener com- plete control of the volume of sound, has recently been perfected by E. T. Jones, of New Orleans. His invention consists of a coil close to the phonograph reproducer, the vibrations of which are said to set up feeble currents. These currents are led to head phones, where the music is faithfully reproduced. With a small amplifying set introduced into the circuit, the volume of sound can be controlled by turning a thumbscrew. In one test, a dictaphone operator was able to transcribe a wax cylinder, although the man who dictated had not talked loud enough to make a fair cut in the wax. With a loud speaker, any talking device can be heard without head phones. Since by the invention the music is con- verted into an electric current, the instru- ment permits the sending of phonograph music directly over radio broadcasting sets, the inventor claims. This may result in clearer music at receiving stations. Goggles Add Perspective to Motion Pictures (= that give moving pictures perspective and depth, and at the same time enable the spectator to see the pictures in any general color he thinks the action requires, have just been invented in Europe. Three colors are usually sup-

Green, blue, and red color effects are obtained by use of these glasses plied—green for outdoor scenes, blue for the night close-ups, and red for fires. The device works on the principle of the stereopticon. Each eye sees the movie through two lenses placed some distance apart. Although there is but one film on the screen, the pictures are said to have been taken in such a way that when viewed through the two glasses the scenes appear to be in three dimensions.

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Small Log Pierces Tree without Shattering

FoR anything you want to know about radio, write to POPULAR SCIENCE MONTHLY’S Information Department.

SLIPPING down a steep mountainside recently near Slate Run, Pa., a 4-inch log drove through a 12-inch tree like a cannon-ball, suggesting that momentum, rather than hardness, is the great factor in penetration. The small log struck the tree a blow of 30,000 foot pounds—equal tothe impact of 15 tons falling one foot. This is calcu- lated on the basis that the log weighed half a ton, and gathered a speed of 20 miles an hour in its course down the mountainside.

Paper Your Own Walls with an Automatic Machine A HAND-OPERATED wallpaper ma- chine that, automatically performs the technical details of papering has been invented by Stanley Pytlak, of Mc- Mechen, W. Va. The roll of wallpaper is placed in a metal cylinder, from which it is unrolled by the turning of a crank. As the paper emerges, the side next the wall is automatically covered with paste by a rotary brush fed from a small paste tank, while a similar dry

As the paper unrolls, brushes paste it and press it down brush on the outside of the paper presses it smoothly against the wall. The operator moves the machine down the wall by hand, keeping one end in contact with a straight edge and spreading the strips of paper evenly and quickly.

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teh gt on, xi oe 48 gh “ Popular Science Monthly A Super-Junkyard for Battleships Torches Cut 18-Inch Steel Armor into Five-Foot Lengths and Giant Shears Snip Destroyers Apart in Newest Industry Pr sis greatest junk business in the history of the world sprang up almost overnight when the recent Confer- ence for the Limitation of Armaments, in binding the United States, Great Britain, France, Italy, and Japan to ‘“‘keep the peace,” decided to discard more than 2,000,000 tons of fighting ships of three leading powers. In the United States a brand new indus- try was created—that of scrapping or con- verting 845,000 tons from the vessels of Uncle Sam’s navy. This displacement ton- nage represents about 300,000 tons of steel and 4000 tons of scrap valued at millions of dollars. The gigantic task of literally sawing apart the heavy steel armor of modern fighting ships has called for methods en- tirely new. Sledge and cold chisel are tools of the past. In their place are the sawlike flames of oxyacetylene torches that rip the toughest steel armor plate, from 10 to 18 inches thick, into five-foot lengths, as if they were boards in a sawmill, and 10-ton crocodile shears that snip through six-inch destroyer armor like paper. How Ships Are Torn Apart Consider how the intricate structure of a battleship is put together, plate by plate and rivet by rivet—a task that requires years to complete—and you may realize the tremendous task that confronts the modern super-junkman. Piece by piece, the massive fabric must be torn apart, in reverse order, beginning with fighting masts, then the superstructure, the ar- mored hull, and finally the keel itself. This new industry is interestingly ex- emplified in the yards of the Henry A. Hitner’s Sons Company of Philadelphia, who are the successful bidders for a colossal proportion of the 845,000 tons that the United States must scrap or convert. Tied to these docks today is a navy greater than that of Italy at the beginning of the war, or of the United States ibis Wy Oe ha. 4 htt Pega emeeenge oth iain How the waterline belt of 11-inch ull armor is cut away is shown in this close-up view of the battleship **Maine.’’ Above the armor belit!note the barbettes emptied of their six- inch rifles Photographs © Henry A. Hitner’s Sons Co. Once the most powerful unit of the Atlantic fleet, the 13,500-ton battle- ad ee we above, to Senn ri a rt in es r= mn & ° At the Pw is the pl ng 1 these naval craft, if converted or recom- missioned, may not pass from American registry or ownership, and their armament from one-pound quick-firers to the huge 12-inch rifled cannon on the battleships, must be distempered by burning and then cut up into five-foot lengths. The 18,500-ton Maine presents in 1910. You cannot casually call in a passing junkman and sell him a 13,500-ton battleship of the Maine type. Nor can you tell the small boy of the family to load the 411-foot cruiser Colum- bia, formerly flagship of the Atlantic fleet, on his little ex- press wagon and take it to the “ol’ iron” man and sell it. The Philadelphia company bought these, and many more, ranging from battleships and cruisers down through the list that includes the monitors Mon- terey, Ozark, and Tonopah, tor- pedo boat destroyers, coast tor- pedo boats, Eagle boats whose names are just numbers, and finally reaching the tiny sub- marine A-1 Plunger, which was the grandfather of the present- day S-41 type of submarine cruiser. Tin Under the terms of the sale, granddaddy of all successful submarines, the Hol- land “‘A-1 Plunger” is being scrapped on the deck of the partially dismantled monitor “‘Puritan”’ a concrete example of the dis- mantling and reforging into peaceful plowshares of a battle- ship that was once the most powerful unit-of the Atlantic fleet. The steel hull of this monster weighs about 35 per cent of the 13,500 tons displace- ment; 26 per cent is armor plate, and the balance of nearly 6000 tons is propelling machinery, armament, ammunition, fuel, and general machinery. Armor Plate Cut into Blocks The armor plate is first taken off the inside shell in pieces weighing from 25 to 40 tons, and swung to an upright position in the yard, where the pieces are cut with oxyacetylene torches - into two by five foot blocks that may be readily fed into charging boxes of open-hearth furnaces. Because of the valuable alloy content of nickel steel, this is Jul one 4 chief for s] sf gun syste the ff piece by t impa chase and iron framé mach sile st Th gun lead, assor by th sold 1 ever) of th will 1 stear form up. the Trua Re-e ers, now Ame caus grey with equi qua mac sary non cau in | five clu “bh fro

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July, 1922 one of the most desirable by products, as it is chiefly used by the automobile industry and for special uses when reforged. The almost human machinery that operated gun turrets, ammunition hoists, refrigerating systems, and other intricate nerve centers of the floating fortress, is broken up into small pieces that a single workman can readily handle by the use of stone pile-drivers with a striking This small scrap is pur- chased principally by the gray-iron foundries and treated in combination with low grade iron ore, later appearing, recreated, in the frames of harvesting and other agricultural machinery, engine bases and similar low ten- impact of 100 tons. sile strength iron products. Junk of Greatest Value The most precious “junk” is the copper, gun metal, navy brass, manganese bronze, lead, zinc, and navy composition that are assorted into their different grades, melted by the smelters into ingot form and sold to manufacturers of practically everything in the metal trade. Some of the equipment from the Maine will take form in new ship castings, steam pumps, and propellers. Not all of the hulls of these former fighting craft will be broken up. Many will be converted, as in the case of the torpedo boats Truxion, Worden, and Whipple. Re-engined with kerosene-oil burn- ers, these former destroyers are now carrying fruit out of Central America to the United States. Be- cause of the speed these clean-lined greyhounds of the sea can attain with comparatively low powered equipment and their seaworthy qualities, expensive refrigeration machinery has been found unneces- sary. In addition they are very eco- nomical, saving lighterage cost, be- cause of their light draft and ability armor, sawing it into five-foot lengths. torch is moved by the mechanism along a With this machine to guide the oxyacetylene torch, the workman makes a clean, straight cut through a 25-ton strip of 11-inch hull The chalk line Arrows point to holes burned through 13-inch guns in the main battery of the battleship ‘‘Wisconsin” to prevent possibility of their use as deadly weapons pan pay ee EEA to go up shallow rivers on high tide and lay off plantation wharfs for loading. When not so converted, the destroyers already purchased by the Philadelphia firm—and they number 50 former menaces to Germany’ssubmarines— are ripped apart with powerful chis- els operated by compressed-air de- vices. These pieces are melted and rolled into various shapes for struc- tural steel, rails and sheet plate. Old Troopships Are Valuable Former English troopships that saw long service in the Indian seas, H.M.S. Malabar and Hoéspur, are lying in the berths where the inter- national cup defender Columbia and Admiral Farragut’s old — flagship Franklin once lay, when these ships, together with the Jamestown, Santee, and Keystone State, were previously wrecked by the Hitners. The old troopships are very valuable from the standpoint of “scrap,” being constructed of the purest wrought iron that is convertible into staybolts, etc. Golfers Drive A NINE-HOLE golf course has recently been installed in a department store in Portland, Ore. The length of the fairways varies from five to 25 feet, but the putter is not the only club used in the indoor game. To play the “bunker hole,’’ for example, you must drive from a tee over a high bunker and into a net over Indoor Bunkers beyond. To clear the bunker, the ball must be driven with a force that would send it 200 yards on an outdoor links. The course was built by laying boards over three inches of undulating earth spread on the floor. On the fairways, this earth is covered with boards and canvas, while the “rough” is represented by real turf. Real turf is used for ‘‘the rough” in this nine-hole course, while the fairways are of boards laid over three inches of earth. golf course is laid out in a Portland, Ore., store This miniature Adjustable Creeper Gives Comfort # 4 JUS UNG HANDLE — you can work comfortably on the flat of your back under the car, if you lie on a- garage creeper with a headrest that you can raise or lower by pulling a hand lever. The end of the creeper consists of a padded cushion about six inches wide, sup- ported by two pairs cf flat steel bars, pivoted in their centers, with their lower ends sliding on two round bars extending across the creeper beneath the frame. When the hand lever is pulled, the lower ends of the bars are forced together, raising the headrest. The lever can be locked in any position, leaving both hands free. NATURAL soaps are found in the root of the Spanish soap root, the soap berry of Chile, South America, and the bark of the soap tree of Peru, South America. ST IEE es = te eee = oe aon ones Ha x PEM nS war at an arma —werignenoa tae oer, = = SS ee » ee Sateen SE F PR tae © + a ea ERE ws mes OEE SLA yee ip atid. cealapelines ee

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MOG eaibdnlinn eaten _ ; (hick Protea tng” > Dovcars How the small cutting wheel shreds and inks the paper of the check thick, much like printer’s ink, so that no reservoir other than a small felt pad is necessary. To this a drop of ink is applied with the end of a match once or twice a year. The ink pad is built into the cap of the pen.

Would You Row without a Backache? A BACK rest that converts an oak thwart of a boat into an armchair has recently been invented by Messrs. Polha- mus and Gillette, of Los Angeles, Calif. While the oarsman is rowing, a spring in the metal frame holds the rest constant] against his back. The device folds so that it may be carried under a person’s arm, and it will convert an old log, a plank, or a rough stone into a comfortable chair. Popular Science Monthly

Radio and Lightning “HOw will lightning affect my radio set? Is there danger to my home during summer thunder showers?” Thousands of new wireless fans, worried by these questions, have recently become more interested than ever in the whole subject of lightning. Dr. Charles P. Stein- metz, the recent creator of “labor- atory lightning,’ and a lifelong student of the vagaries and se- crets of the real thing, relates his latest discoveries, in an article for the next issue of POPULAR SCIENCE MONTHLY, which will interest radio fan and general reader alike.

Semi-Automatic Welder Seals Uneven Seams phew A outfit oubles speed of hand weld- ing

AUTOMATIC g er WELDER ~ FLEXIBLE HEAD WIRE GUIDE WELDING WIRE A NEWLY perfected semi-automatic welder is said to double the speed of the hand-operated welder, while retaining the continuous features of the full auto- matic machine. It allows the operator to direct the are and is designed for welding products where the seam is of irregular con- tour, or the work too large to permit the use of the automatic machine. The new electric apparatus consists of a welding tool resembling an automatic pistol connected with a flexible wire guide for the electrode wire, and containing a switch that controls the panel of the auto- matic welder.

Carry Your Checker Board in a Pocket Roll A CHECKER board printed on a rubberized fabric that can be rolled up and carried in the pocket enables the enthusiast to enjoy his favorite game any- where he may happen to be. *

When rolled, this rubber checker- board becomes a case for the counters Ponular Seience Manth

Ju mos last hor tori all Ma vail ate the bur, util met tra on tele loo! spil hei

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‘July, 1922 53 Metal Balloons May Draw Power from Sky Collecting Atmospheric Energy with Metallic Bags, Experimenter Claims to Have Found a Way to Utilize “Free Electricity” By P. J. Risdon \ , Y ILL the vast reservoirs of dormant energy, represented by the differ- ence in potential between the at- mosphere and the earth, be harnessed at last and utilized to light and heat our homes and to turn the wheels of our fac- tories? The limitless supply of potential energy all about us has long been recognized. Many electrical engineers have sought in vain for satisfactory means of harnessing it. Recently, however, M. H. Plauson of the Traun Research Laboratory in Ham- burg, Germany, has devised a scheme for utilizing this free electrical energy—a method that may be described as power transmission by waves through the ether, on much the same principle as wireless telegraphy and telephony. Spikes Cover Balloon Surface Plauson makes use of a number of bal- loons with metallic surfaces covered with spikes. These balloons are sent up to a height of several thousand feet. The charge is conducted to earth by a metallic cable attached to each balloon, all the cables being connected with a circular con- ductor leading to the power stations. By means of special transformers (details of which are not yet available), atmospheric charges are converted into electromagnetic vibrations of the ether. These vibrations are so powerful that they operate motors attuned to respond to them, in the same way—but of course on a far more powerful scale—that one tuning fork when struck will cause another exactly similar tuning fork to vibrate. The lightning flash, always suggesting tremendous power, has long tempted ex- perimenters to extract power from atmos- pheric electricity. In the year 1753, Ben- jamin Franklin experimented with a kite with a wet string and succeeded in con- ducting electricity to the ground and charg- ing condensers with it. Afterward, by the use of a metallic string, electricity was drawn from the atmosphere, producing sparks nine feet long. The difference in potential is due to charges of static electricity, which are be- lieved to be positive in relation to the © Popular Science Monthly Publishing Co. Inc. . eax for x 0 pepe * © Popular Science Monthly Publishing Co., Inc. with a circular conductor. By means of metallic-surfaced balloons covered with spikes, Herr M. H. p= Al proposes to collect electric charges from the atmosphere, conduct- ing the charges to earth for commercial use by metallic cables connected Inset shows a balloon in cross section Diawing by G. H. Davis earth. It is something like the positive and negative charges on the plates of a charged condenser. But although a charge may be conducted to earth, or reach the earth from a cloud with a flash that we call lightning, it is not the same thing as a current of electricity and cannot be used to drive electric motors directly as a current can. The explana- tion is simply that the current from a dy- namo is generated and used at a certain predetermined rate, while in a static at- mospheric charge there is a large amount of electricity, at a very high potential dif- ference, that endeavors to reach the earth all at once. When we consider that a cur- rent of 10,000 volts is necessary to spark across a one-eighth-inch gap, it is easy to Drawing by G. H. Davis r rihers efor. a. age of Blectrict mi the ap 4 f ommercial Spark nting pt fe Current agent Fusiad magnets } ot Atmospheric charges conveyed to the power station through the steel cable at “a the left are transformed into electromagnetic vibrations of the ether, which, in turn, operate motors appreciate what an enormous potential difference there must be for a charge to produce the length of spark through air that we see as a flash of lightning. Early experiments with atmospheric electricity, whether with kites like Frank- lin’s or by means of metallic rods project- ing high into the air (such as that used by Richmann in 17538, which killed the experi- menter by a great discharge), were made more especially when thunderstorms were imminent. Plauson, however, does not propose to wait for these conditions, which arise from accumulations of electricity on minute particles of moisture in the air, that collect locally and thus set up such a powerful influence that the charge breaks through the resistance of the lower strata of air and flashes to earth. Would Prevent Thunderstorms Plauson’s idea is to take advantage of the average difference of potential, by which means he believes that thunderstorms will actually be prevented in given localities where his apparatus is at work on a big enough scale, by maintaining a condition of local equilibrium and thus preventing the accumulations that are necessary be- fore lightning can occur. Whether he is right or not in his forecast can, of course, only-be proved by experiment. Up to the present his method has not been tested on a large scale, but he claims that, with two balloons at a height of 1000 feet, he obtained power equal to 81% kilo- watt hours a day. as san Sa ceglide ae 5 ale aia St a FEEL ES OA Pe oe Lassie: oreo ogre san a acerenammapenne aT c ~ pi ARTO SA SL REIT E Eet Ee ens ee aa et lnieed Ate oe Pr en 8 —

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este ganeten sk fe aR 54 Gas Pistol Stops Fire or Thief saan OU can stop either a fire or a burglar with a recently invented gas pistol consisting of a small cylinder filled with compressed gas, and slipped onto a pistol grip handle. The pistol is dis- charged by simply pulling a trigger. This releases a pin, which punctures the container. The gas, released, flies out in a dense cloud under its own pressure, enveloping the fire or suffocating the intruder, as the case may be. No gas is released toward the rear, so that a person may fire the pistol without wearing a gas mask. The gas is said to have much the same effect on a burglar as tear gas; for while it will incapacitate him for a short time, it will do him no permanent injury. On a fire, the gas acts like the car- bonic acid gas of the usual extinguisher, smothering the flames. Arm for Street Car Forms a ‘*Safety Zone’’ ROJECTING arms which are extended from the rear of a street-car at stopping- points will afford passengers descending from the cars real protection, if the inven- tion of Col. Charles Gore of Los Angeles, Calif., is adopted. Many accidents have already been prevented by the present “safety zones,” although these depend on automobile drivers’ knowledge of and obedience to traffic rules. Colonel Gore’s device is a telescoping bar that is automatically extended as the How the telescop- ing arm protects passengers motorman cuts off the power preliminary to a stop. It remains extended until the car is ready to start again. The bar is ex- . tended and retracted by compressed air. In addition to forming a safety zone wherever it may be necessary—whether this be at the usual street crossings or not —the bar prevents women and children from walking around the rear of the car the wrong way. This, too, has been the cause of many accidents. The bar also enables the car to be loaded more quickly, as it eliminates jamming in the doorway by forcing the crowd to form in line. ‘DéliGined Aleem Clock Rings Tiny Gong TH alarm clocks, measuring 14 inches . square, are the latest novelties to appear on the market. One handle winds both the time and alarm springs, while the entire case forms the gong for the alarm. The clock is con- structed on practically the same principle as the familiar alarm watches. Popular Science Monthly Sticking Machine Seals Envelopes Securely | A new type of envelope sealer, the en- velopes to be sealed are stacked with their flaps down and toward the front of the machine. Then a thin brass plate moves up as a hand wheel is turned and, sliding in between the envelope and its flap, moves the envelope ahead. After it has moved a certain distance, another sheet of brass presses it against a moist felt under the top Envelopes are sealed and stacked by turning a crank brass, thus insuring a uniform moistening of the gum. n The upper brass now moves still farther forward and at the same time a pair of rubber rolls open to receive the envelope. As it enters them, they come together tightly and apply the pressure necessary to insure the flap sticking firmly. A guard in front of the rolls keeps the envelopes right side up and guides them to the rack in which they are stacked. The moving parts of the machine consist of two gear wheels, the two rolls and three sets of cams with their attachments. Rustless Iron Holds Polish | pond! that will not rust has recently been produced in Sheffield, England. The new product is said to be superior to the so-called stainless or rustless steel, since it is rustless in the ordinary state, and does not require heat treatment. It can be worked in the cold, soft state by all mechanical processes, and after be- ing polished becomes rustless. It seems to remain so indefinitely. In tests after pro- tracted exposure to the fume laden air of industrial centers, the polish on the metal was as bright as the day it left the mill. Limousine Is Converted into an Ambulance Ze i ee Ow ry For the use of institutions that desire to economize by combining an ambu- lance and a pallbearers’ coach in a single vehicle, a limousine has been constructed that may be converted at will from one to another of these uses. In appearance the car resembles a stand- ard limousine. By folding up the seats on the side, and dropping the forward seats into a recess at the front of the compart- ment, the machine will admit a regular ambulance cot through the double doors. ee [eae DS ee . = Jul you ' secre cove This suffe press such appl that glan zoneé ache squé ing ford by « Ger you can of y by sec pre of t pre thu arc ne! pri

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July, 1922 Queer Science Stops Pain by Pressure Pinching Fingers Deadens Toothache, while Rubber Band on a Toe Will Ease Smashed Thumb, Says “Zone Therapy” Expert By Ralph R. Perry AVE you ever, after accidentally H pounding your thumb, seized it and held it tight to stop the pain? Do you know that when you did this, you were unconsciously applying one of the secrets of an extraordinary medical dis- covery of the day, called ‘“‘zone therapy’’? This queer new method of preventing suffering in one part of the body by mere pressure on another part is said to have such astonishing results, and to be so easily applied by any layman to his own body, that the whole subject may seem, at first glance, a scientific absurdity. Zone Theory Is Demonstrated And yet, actual demonstration of the zone therapy theory—proof that a tooth- ache, for example, can be stopped by squeezing one of your fingers or correspond- ing toe—is credited to a physician in Hart- ford, Conn.—Dr. William H. FitzGerald— by other prominent medical men. If you experiment with Doctor Fitz- Gerald’s remarkable zone therapy system, you may find, among other things, that you can: Cure a headache by pushing on the roof of your mouth. Relieve an aching first or second molar by pressing firmly the knuckles of your second finger, and the wisdom tooth by pressing firmly the corresponding sections of the third and fourth fingers. Stop the pain of a sprained right knee by pressing your right elbow. Relieve the hurt in your left thumb that you hit with a hammer by binding a tight elastic band around your left large toe. In fact, according to the expo- nents of zone therapy, a pain in practically any member of your Beginning at the front of the jaw, an ache in any one of the first three teeth on either side is controlled by pressure on the thumb on the cor- responding side; the next two teeth by the forefinger; the next two molar teeth by the second finger and the wisdom tooth by the third and fourth fingers As proof that pressure on one part of the body will prevent pain in many other parts, Doctor FitzGerald shows this photograph of a patient who, after pressure on the dental nerve of the left lower jaw, felt no sensation of pain from the stickpins in her left arm, hand, and chin body may be partially or entirely put out of business by simple pressure on another member in the same bodily “zone.” To the layman who succeeds with it, this mysterious method may bring greatly needed relief when troublesome aches and simple rules which he outlines you can often eliminate pain entirely. The layman may apply zone therapy to himself without danger. Usually, it is beneficial; in any case, it is harmless. How Zones Divide the Body “Zone therapy” is the name applied to the method, because Doctor FitzGerald has found that for purposes of relieving pain the body may be divided into 10 vertical zones, five on each side of a center line. The ex- tremities of the zone division lines are the fingers and toes. For example, the first zone on either side of the body begins at the big toe and runs up the entire body, includ- ing the chest, back, and head, extending down the arm and ending at the thumb. The second, third, fourth, and fifth zones originate similarly in the first, middle, ring, and little fingers and run to the correspond- ing toes. Here are some of Doctor FitzGerald’s conclusions, based on the zone theory: Pressure across any section in anterior half of any zone will relieve pain in any other part of that half of the zone, and pres- sure across any section in posterior half of any zone will effect the same relief in that zone, although pressure at some points is more effective than at others. An impor- tant point to bear in mind is that it will do no good to squeeze your right toe to reduce pain in your left thumb; or to press upon the first finger to cure an injury that should be treated by pressure on the second finger. Areas of pain run up and down, and also crosswise, as from the various orifices of the body. In each zone, the finger corre- sponds with the toe, the wrist with the ankle, and the knee with the elbow. Therefore, wherever the pain may be, choose the correspond- ing member in the upper or lower part of the body and press firmly at sonfe point where the main trunk nerves are close to the surface— that is, at the joints, where there is little flesh and muscle over the bones. Rubber Bands May Be Used The best way to apply zone therapy to yourself, Doctor Fitz- Gerald advises, is to use rubber bands passed entirely around the proper finger or toe, so as to include every part of the zone, and thus necessarily reach the right spot. Miles from medical aid, the camper under- standing zone therapy may ease the pain of a sprained left knee by firmly pressing his left elbow in the same “‘zone’”’ pains threaten to spoil a summer vacation; when a camping accident to knee or ankle occurs deep in the woods, miles from medi- cal aid. But it may be just as comforting when applied in the endless emergencies of city life. Doctor FitzGerald has discovered that the instinctive habit of pressing firmly on any part of the body that hurts is entirely scientific, and that by observing a few Doctor FitzGerald himself uses a “therapy zone’”’ or spiral spring, for that purpose, but he deciares a rub- ber band, or even a tight bandage, is often as effective. He outlines the method as follows: Slip on a rubber band that is uncom- fortably tight, and leave it in place for from five to 15 minutes. Since this will stop the circulation, always remove it before the end of the finger starts to become blue, and then, if the pain continues, place it on again, repeating the operation several times a day for several minutes if necessary. The continued pressure has been found TS ef RTT IT AT NT TS IY I pon ee ert a wptnent«

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5 a ek ee a vee} rely oh an iecSartghtencsn peat tenement tn -itreiiaans aete ean staneaissiteiant signi Le xe 56 to keep the pain from returning, and in many cases of headache or tooth- ache, to cure the affliction. If the pain returns, apply the tight band again, and if it should persist, call a doctor. Re- current pain that cannot be assuaged by zone therapy, it is pointed out, indicates a genuine pathological condition, and requires the immediate attention of a physician. Since zone therapy in the hands of the layman is primarily a method of first aid, Doctor FitzGerald suggests the follow- ing methods of treatment for accidents that may occur when you are on your vacation, or out of reach of competent medical aid: To ‘“‘push a headache out through the top of your head,” press your thumb, or, better, some smooth, broad surface like a metal knife handle, firmly against the roof of your mouth, as nearly as possible under the spot where you feel the pain. Hold it in place for from three to five minutes. If the pain is very severe, supplement this treatment by pressure on the joints of the fingers or wrists, How “therapy rings’’ are worn on the fingers to block pain on the corresponding side of the body Pain Zones of the Body PRESS ON ROOF OF MOUTH TO RELIEVE HEADACHE PRESS AT ARROW MARK TO DEADEN FEELING IN HALF OF JAW AND CORRESPONDING SIDE OF BODY PRESS ON RIGHT WRIST TO RELIEVE PAIN IN RIGHT ANKLE / PRESS ON RIGHT KNEE } TO RELIEVE PAIN IN RIGHT ELBOW PRESS ON TOE TO RELIEVE PAIN IN CORRESPONDING FINGER How zone therapy, for the purposes of reliev- ing pain, divides the body into five vertical zones on each side of a center line, is described in the above diagram. Extremities of the zone division lines are the fingers and toes. The figure is shown anesthetizing the entire left side of body by pressure on the left dental nerve of the lower jaw, as described in the inset above especially on the top or back of the hand. For a racking headache ‘“‘just back of the eye,’”’ compress the first joints of both fore- fingers or both forefingers and both middle fingers. This usually gives relief, unless the headache is due to prolonged eye strain or toxic absorption from the bowels. If a tooth begins to ache, press the cheek immediately over that particular tooth, or squeeze the gums be- tween the thumb and first finger for from one to four minutes. In addition, place a rubber band on the proper finger, remembering that, starting at the center of the mouth and counting toward the rear, the first three teeth on either side are controlled by the thumb, the next two by the forefinger, the next two molar teeth by the middle finger, and the wis- dom tooth by both the fourth and little finger of the hand on the corresponding side. Pressure should be applied on the first orsecond joint. Since the zones some- times overlap somewhat, it may be best to press upon two fingers. The best aid in treating other aches and pains in- cident to a vacation is a blunt pointed aluminum To locate a pain-re- lieving spot, press the teeth of a comb on the wrist, then rotate the comb comb with strong teeth. This enables you to search out and locate the exact spot at which to apply the pressure that relieves the pain of such injuries as a sprained ankle ora wrenched knee. Place the teeth of the comb upon the knuckles, wrist, or elbow, as the case may. be, and rotate it entirely around the joint, pressing firmly. You will soon find a spot at which the pain is lessened, and that is the place to adjust your rubber band, or to squeeze with your fingers. Is it always possible to find such a spot, and if found, will the pain always disappear? Doctor Fitz- Gerald makes no elaims so sweeping. Zone therapy, he points out, is no panacea nor cure-all. The reaction of different individuals to it varies greatly. With some persons, pressure therapy produces complete anesthe- sia, in which minor surgical operations can be performed without the least pain to the patient. With most persons, however, zone therapy pro- duces analgesia—a reduced sensibility to pain. Doctor FitzGerald’s ex- perience is that specialists in zone therapy can deaden sensation in about 80 per Popular Science Monthly cent of all cases, and can make the nerves quite insensible to pain in about 65 per cent. Among laymen, about half can relieve their own pain, and about 60 per cent can reduce it. No theoretical explanation of the results obtained by zone therapy has been attempted. The discovery indi- cates, however, that the relation among the various nerves of sensation is more intimate than physicians have believed. Certain it is that the control centers in the medulla oblongata, at the base of the brain, can be easily stimulated or deadened by proper manipulation at the nerve ends. Zone therapy, as sometimes inter- preted, may depend upon what physi- cians term ‘“‘nerve block.”? As you press upon the nerve over the seat of injury, or upon another nerve that joins the in- jured one at the brain, you prevent it from transmitting full knowledge of the injury. It is as if the nerves formed a telegraph system, and you were able to cut the wire—producing anesthesia—or to scrape off the insulation, thus reduc- ing the current that is transmitted and Cross section of finger tip showing nerves between nail and bone. The expert finds points such as this, where bones or knuckles are near the surface, the best places to apply pressure to deaden pain producing more or less pain insensibility. Whatever the explanation, Doctor Fitz- Gerald, working entirely by zone therapy, claims to have cured malignant cases of goiter. “The effect of zone therapy certainly is not due to mental suggestion,” says the dis- coverer, “for if you press the wrong finger, no relief follows, and the method is often effective where mental suggestion fails. Hay fever, for example, can frequently be cured by pressure in the mouth at various points in line with the nose. A sneeze can usually be stopped by pressing the center of the upper lip against the teeth with the first finger. Vomiting and car sickness—_ occasionally, even seasickness—will yield to steady pressure or stroking with a metal comb on both surfaces of the hands, in the first and second zones. Lumbago and pains affecting all zones can be helped by pressing on the tips of the fingers, or by grasping a comb so that the prongs press against the middle joints of all the fingers, and the thumb on the comb end. Cross stroking to the median line on extremities or head or body is usually very effective in most pathological conditions, as is also con- cussion on any part of zone (concussion is not to be limited to the spine). “The principles of zone therapy are easy to learn. It can do no harm. In sudden emergencies, or when far from a doctor, its use may enable you to save yourself or your best friend from hours of excruciating—and unnecessary—agony.”

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July, 1922 1e ee ® . ° : Corn Fuel Is Cheaper than Coal for Firing Brick Kilns 0 Com may be Some persons have i used as a stand- protested the use of a ard fuel in firing the a food as a fuel, but " brick kilns of a clay others find it hard " products company to understand why . at Adel, Iowa. At burning corn in a i present prices of furnace is worse * corn and coal, more than fermenting it if heat can be obtained and then burning “ by burning the corn the alcohol in a rd itself than by selling tractor, especially it and burning the when corn worth . coal it would buy. $100 as food can 3 The practice of give heat equal to “ burning corn was $150 worth of coal. first undertaken to The relative heat- ; help the farmer’s ing values of corn t business by giving and coal, as esti- m him a market for his mated by the United . crop in a bad year, States Department . but corn has proved of Agriculture, are . to be such an effec- as follows: a tive brick making Corn at 10 cents a , fuel that unless corn Instead of the coal pile, the corn pile. Firing brick kilns with corn fuel, bushel equals coal at rises above 20 centsa as shown above, has saved money for an Iowa clay products company $5 aton; at 16 cents bushel, or coal falls , a bushel it equals below $10 a ton, the burning of corn is Roughly speaking, two tons of corn will coal at $8 a ton, and at 22 cents a bushel likely to become a common practice in give as much heat as one ton of coal, and it equals coal at $15 aton. Such figures the Middle West. has about the same caloric value as wood. justify the use of corn as a fuel. > Huge Mirror Perfected for Astronomical Use Polishing the 40-inch surface of the enormous glass disk weighing half a ton MERICAN astronomical observatories will no longer be compelled to buy their best telescopes abroad, for Donald F. Sharp, of Buffalo, N. Y., has succeeded in casting and polishing a 40-inch reflector mirror that weighs half a ton. Cooling the huge piece of glass with per- fect equality throughout is the great diffi- culty in making such a mirror. If one part cools a single degree faster than another, a strain will be set up in the glass that will distort the image reflected from it. It was not until a special electric furnace was designed to keep the temperature within the limits of one fifth of a degree Centi- grade that the casting was successful. Reflecting telescopes contain no lenses, but obtain their magnification by gigantic mirrors made of heavy disks of glass with a thin coating of metallic silver. The silver is applied to the front surface instead of to the back of the glass, as in ordinary mir- rors. The face is carefully ground into the form of a paraboloid. This focuses the light rays in a point, from which a small plane mirror reflects the image to the eye- piece. The disk will be used in a huge telescope now being erected at the Uni- versity of Arizona. Rudder Angle Indicator Simplifies Docking | aber nade a liner without a tug is difficult even for the most skilful pilot unless he has accurate ° ~, knowledge of the position of the ship’s rudder. ” mae With an electric rudder indicator developed by . 2 a the originators of the gyroscope compass, the position > ye ie a of the helm can be determined to a degree. At the v oto NG stern of the ship the moving arm of a transmitter is We. a ‘ fastened to the rudder stock. As the rudder turns, a “a bes oe °8 segment at the bottom of the moving arm makes A) 20° HeLm ance INDICATOR 99 contacts with a controller inside the box, so that an \ os" 5 electric current is sent over a multi-wire cable to aoa 30 an indicator located near the steering wheel. 3 3 y The indicator consists of a step-by-step motor that Dee, . is self synchronizing, and that produces a powerful torque or twisting motion, varying with the intensity of the current. The hand of the indicator is bolted to the shaft of the motor. The contacts in the con- troller at the stern correspond to every position of the helm between dead ahead and 35 degrees right or left. These are repro- duced correctly on the pilot house dial. HELM ANGLE Position of the INDICATOR ON helm is regis- BRIDGE tered in de- grees INDICATOR ON AFTER STEERING STATION Apron Trap for Balls Saves Bowlers’ Temper yay APRON trap for the bowling alley, has recently been invented by Walter to prevent the ball’s rolling back Choinski, of Milwaukee, Wis. from the rack end of the return trough Balls returned to the bowler frequently do not have suffi- cient velocity to ascend the in- cline that delivers them to the stor- agerack. Some- times they roll back down the alley. This the new invention obviates by a canvas apron suspended over the trough so that the ball can roll under it, but will be stopped Returning down the trough to the bowler, the ball rolls if it starts to roll under a canvas apron, which checks it from rolling back back. Pete ee ech ae

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58 Popular Science Monthly Fantastic Summer House Formed from Mud Pile ALLS of soft, sticky mud served as building forms in the recent construction of a unique summer house, of irregular and fantastic shape, which not even the builder, a resident of Cincinnati, can dupli- cate. The completed house, which appears as if it had come out of some book of fairy tales, is formed. of concrete; yet during construction a huge and apparently shapeless mud pile rose on the site. T he foundation was laid three feet below the ground by building a double mud wall very much as a child would build mud molds were it—by throwing great double handfuls into place haphazardly. From time to time the space between the double walls so formed was filled with semi-liquid concrete. The mud forms, of course, were supported and held in place by In this manner the concrete walls acquired their irregu- lar surfaces, molded by the lumps and depressions in the mud sur- framework. After the concrete walls had set, the away by a hose. The metamorphosis of the huge mud pile into an unusual summer house is shown above. The fairylike interior is shown at the right spe ae dug out and washed rounding them. Wherever a cavity ap- pears in the completed summer house, it marks the position of a lump of mud in that part of the mold which prevent- ed the cement from forming a smooth wall. Thus the cabin slowly rose from the ground like a mushroom, resem- bling a gigantic mudpile held in shape by.a conglomerate mass of rocks, tim- ber and branches. The roof, while reenforced with steel rods, was built in the same fashion. . Tons of mud were used in its construc- tion. Here again the irregular, cave- like interior was pro- duced by the mud mold, for none of this was added after the house was completed. After the building i] was finished, the de- signer waited two weeks for the con- crete to set, and then commenced to dig away his mud mold. He tore away the hardened crust of mud from the ex- terior, then dug out the interior. Finally, by means of a hose, the entire structure was washed clean. Air Blast Mixes Concrete Evenly ‘RE problem of mixing the ingredients of concrete in the correct proportions and at the same time so thoroughly as to insure a perfect coating of cement around every particle of sand and every piece of stone has been met successfully by a re- cently perfected portable mixer in which cement is blown by a fan in a cloud that covers the aggregate. The output of the new portable machine is from eight to ten cubic yards of con- crete an hour. ' Hand gaging or measuring = Of ingredients is unnecessary. X The cement SAND AND STONE ee and aggregate are simply dumped into their respective troughs and hoppers and the machine does the rest. It continues to work automatically, mixing in the correct proportions, as long as it is kept constantly charged. At one end of the carriage is a double hopper, into one part of which is delivered sand, and into the other part gravel and stone. At the bottom of the hopper are sliding doors, so designed as to insure the right proportion of sand to stone. Through these doors the aggregate drops to a rock- ing tray, actuated by an eccentric. On the _ Wa SPRAY PIPE FALL DOWN SHAF When part double hopper—reach the rotating coats each particle t a NG BUCKETS DOUBLE — icles of sand and stone ooneienly mixed in their progress from the drum, cement blown into the horoughl hly in New Automatic Machine tray the aggregate is mixed, then delivered into elevating buckets on an endless chain. These buckets drop the material to a re- volving screen, which sorts the particles so that they fall, separated, down a vertical shaft into a rotating, sloping drum. Across the top of the shaft is a horizontal, perfo- rated pipe from which water is sprayed on the falling particles. On top of the machine is a pair of troughs in which Archimedean screws work. Ce- ment is delivered into one of these troughs (or lime into the other, as the case may be) and is worked by the screws to the other end, where it drops in front of a fan by which it is blown into the upper part of the rotating drum. The cement enters the drum in the form of a dense cloud that effectually coats all the separated particles of the aggregate as they fall. Material Receives Thorough Coat As the drum rotates, the mass of material is lifted by angle curbs and drops again and again through the cement cloud, thus in- suring a thorough coating of cement. Meantime the mass moves gradually along the sloping drum and finally emerges at the front end of the machife through an opening covered by a hinged door. The speed of the elevating buckets is variably proportioned to the speed of the screws in. the cement troughs, the quan- tity of water delivered being regulated so that no matter at what speed the machine is working, the proportion of the various ingredients remains the same. The pro- portion can be varied by altering the gear- ing. Thus the proportion of cement and aggregate may be varied from one to two to from one to twenty. The makers claim that their cement mixer makes a much stronger concrete than any other method. July, G*:. ad by usi handl : Ridle locks t operat Movi latch

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July, 1922 —— é Adjustable Lawnmower Shaves Terraces ee RASS growing on terraces can be cut as easily as that upon the level lawn by using a lawnmower with an adjustable handle, invented by Robert R. Kitchel, of Ridley Park, Pa. Pressure on a toe clip locks the handle at the angle desired. The operator walks on level ground at the foot of Moving on a turne table, the handle latches at various angles the terrace, and cuts one longitudinal swath above another on the sloping surface. The adjustable handle is on a turntable that latches in the central position and at several angles up to a maximum of 30 degrees on each side. You Can Now Change Tires in a Few Seconds (y= nut, instead of the usual eight or ten, locks a new demountable rim, in- vented by H. N. Moody, of New Orleans, to an auto wheel. The tire may be tight- ened or released almost instantly by means of a locking cam. To the surface of the felloe are welded 10 metal cleats placed at an angle of 15 de- grees. The inside of the demountable rim has 10 projecting lugs, each half an inch in diameter and a quarter of an inch high. When the lugs are wedged into the cleats, the rim is locked securely on the wheel. The locking is accomplished by a single large cam disk that works between the cam lugs on the rim. One half turn of this master cam releases the tire. One half jane of a dnale ameter cam nut, shown in the inset, releases tire 59 ranging from 3000 to 5000 feet. With rag men as pilots, the gliders will be released from navy dirigibles at heights they soar downward at a speed of about 45 miles an hour, they will be targets for anti-aircraft guns and small arms of the Atlantic fleet below Go manned by dummies will be used to test the anti-aircraft guns of the Atlantic fleet during coming maneuvers off the Virginia capes and Cuba. During the bombing tests off the Vir- ginia capes last fall, naval officers objected that the tests were not convincing, since aviators would be shot down if they should attempt to approach a modern dread- naught and launch their bombs as deliber- ately and from such low altitudes as they did against the anchored German ships. Dirigibles Will Tow Gliders To meet these objections, and at the same time give the gunners practice under battle conditions, a fleet of small gliders will be towed by dirigibles, it is reported, and re- leased above the battleships from heights varying between 3000 and 5000 feet. Rag dummies in the place of pilots will be fastened in the gliders to give the marines using small arms a chance to test their marksmanship by picking off ‘airplane crews.” The gliders will be released in fleets of five, it is announced, and are expected to maintain an average speed of about 45 miles an hour as they soar down to the water. This is only about half the speed of bombing planes in full flight, but is more nearly equal to that of the giant bombing planes, carrying 2000- and 4000- pound bombs, which succeeded in sinking the German battleships in the former tests. The gliders will be much larger than those used in land maneuvers by the army and navy. Each could carry two men with perfect safety, and accordingly they are somewhat larger than the majority of gliders now being built in Germany. If the tests are successful, the results will be valuable not only in determining the value of anti-aircraft gunfire, but in proving that the modern glider can be safely used to descend from the greatest heights. Practically every ship in the Atlantic fleet, it is said, will take part in the attack on the gliders. As a special service to readers, the Editor will be glad to supply the mames and addresses of manufac- turers of devices mentioned in POP- ULAR SCIENCE MONTHLY.

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a 60 Belt Lifts Coal from Car to Truck The flat extension of the unloader, shown at the right, fits between the hopper of the gondola car and the rails. Coal falls from the hopper to a moving belt and is ounled up an incline to the dealer’s truck Y TRANSFERRING 30 tons of coal from the bottom of a gondola car into the coal dealer’s trucks in an hour, a newly designed belt-type car unloader is said to enable the small dealer to handle his mate- rial as cheaply and efficiently as would be possible in larger scale operation with raised trestle and gravity bins. Supporting the conveyor in an in- clined position is an ingenious framework mounted on the wheels on which the machine is transported. The machine is wheeled into place be- neath the car. by one man, who starts a 15- horsepower gasoline motor. As the coal drops from the hopper of the car, it falls on a moving belt of jointed steel plates that carries it up an incline and dumps it into the truck. No hand shoveling is required. The conveyor extension that goes under the gondola car is flat enough to fit between the hopper and the rails. Speed of opera- tion will be slightly increased if a tie is re- moved and a shallow pit dug beneath the rails, in which the unloader is permanently set. This eliminates the necessity of re- setting the unloader for each car. The unloader will also handle material from storage piles. Popular Science Monthly Poison Gas Is Used to Eliminate Rats Ne that the world is at peace, the United States Chemical Warfare Ser- vice has declared war against the pests that eat up the farmer’s profits. Phosgene and mustard gas are proving as effective against rats as against an advancing enemy. Rats and mice have been removed with remarkable success by flooding their underground tunnels and nests with phos- Spraying a rat tunnel with gas gene gas. The infested ground is covered by gas experts protected by masks, and carrying the gas in portable compressed cylinders. Whenever they locate the en- trance to a rat tunnel, they insert the delivery tubes in the entrance and send in a blast of gas that reaches the rats even in the remotest crevices. The One-Wire Aerial Is a single-wire aerial as good as a multi-wire aerial for radio receiving pur- ses? In speaking of a four-wire, 100- oot aerial, does the length refer to the length of each wire or to the combined length of all the wires? —W. S. U. For receiving purposes, a one-wire aerial is just as good as a multi-wire aerial. Use a wire about 100 feet long and about 50 feet high. In speaking of a four-wire, 100-foot aerial, the length refers to length of each wire. ‘‘Climate’”’ and ‘‘Weather’’ What is the difference in meaning between the terms “climate’’ and “‘weather’’?—E. W: In speaking of the ‘‘weather’’ we mean the condition of the atmosphere at some par- ticular place and at some particular time. We refer to the temperature, the percentage of sunshine, or cloudiness, the wind velocity, and the precipitation of rain on a particular date. By ‘‘clinfate’’ we mean the average atmospheric conditions existing in a certain locality for a period of time, especially as they affect the animal and vegetable life of the region and the health and comfort of the inhabitants. How to Adjust Your Set Please give me full directions for tun- ing a vacuum tube set. —B. B. K. Full directions for tuning a vacuum tube outfit are too lengthy to be given in this col- What Do You Want to Know? umn or in a letter. This phase of radio is treated in detail in a chapter called ‘‘How to Adjust Your Set,”’ pages 32 to 48 inclusive, of POPULAR SCIENCE MONTHLY’S new booklet, ‘‘The Stand- ard Radio Guide.’’ Bysending 50 cents you can obtain this book from our Book Department. Alloy Melts at 212 Degrees I want to make an alloy that will melt at the temperature of boiling water (212° F.). What metals shall’ I use and in what proportions shall I use them? — An alloy made of eight parts of bismuth, five parts of lead, and three parts of zinc will give you the desired result. - Indoor Aerial Is Safe What kind of lightning protection is best for an indoor aerial? —J. F. D. Lightning protection is unnecessary for any type of indoor aerial. How to Keep Flowers Fresh How can cut flowers be made to retain their freshness for a longer time than is ordinarily the case? —J. S. W. Dissolve small quantities of ammonium chlo- ride, potassium nitrate, sodium carbonate or camphor in the-water in which the stems are inserted. The presence of one or more of the above chemicals stimulates the cells to action and opposes germ growth, thus keeping tac flowers fresh for a longer time. Write the Information Editor About Your Problems in Radio Receiving at 200 Miles I am about 200 miles from KYW (Chicago). What kind of a radio set will I need to receive the concerts sent out by this station? —L. D. C. Many amateurs get good results over such distances with single tube detector sets, but we believe that you should have no difficulty receiving the concerts if you use a vacuum tube set with two stages of amplification. The Velocity of Light What is the generally agpegend figure for the velocity of light? —P. A. The velocity of light has been published by the ‘‘American Ephemeris”’ at different times as 186,380 and as 186,330 miles a second. In recent years, however, after very elaborate determinations, 186,324 miles a second has been adopted. EVERY reasonable specific query in the field of general science addresséd to the Information Department will receive a prompt reply. ; While lengthy replies cannot be given to complicated questions involving extensive research or computations, this department aims to be of maximum service in supplying information as to what books or other sources may contain answers to these questions. Legal and medical queries cannot be answered. A stamped addressed envelope must accom- pany each question, but the writer’s name will not be published if he so requests. Address the Information Editor, Popular Science Monthly, 225 West 39th Street, New York City. Popular Science July HI bd eggs, Ange and ¢ one cor inn lift sul

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~~ Fr we § Oe ee ee July, 1922 Bricks, Like Eggs, Now Travel in Cartons ped bricks in individual card- board cartons, as if they were fragile as eggs, has been found profitable by a Los Angeles concern. Formerly, finely pressed and enameled bricks were often chipped and broken in transportation. The new protec- tion eliminates breakage entirely. © American News Service Tire Tube for a Swing! rs a long stretch, but the rubber still holds. The test stunt shown above is one method recently adopted by a rubber company in testing the flexibility of the inner tube of a bicycle tire. The tube, lifting wheel and rider from the ground, supports a total weight of 222 pounds. Aste Biallee ‘‘Drives’’ Arrow A VARIATION of golf was demonstrated re- cently at Pasadena, Calif., where Samuel G. McMeen has startled orthodox golf players by appearing on the links with bow and arrow. McMeen challenges all comers. As his opponent drives his ball, the archer-golfer shoots his arrow. Each shot counts as a stroke. If the arrow lands on the green within six inches of the cup, it is con- sidered in. Ten Type from One Record Cr dictaphone trains 10 typists at once in a modern business school. One machine is connected with a hollow tube running down the center of a table. The students plug their ear-tubes into small holes in the tube, and all.10 may take dic- tation simultaneously from one record. ‘*A Ship without a Bottom’’ AN IDEA of what happens to the bot- tom of a ship when it is washed in a gale for a mile over reefs and through the surf is pictured above. When the disabled tank steamer F. D. Asche was towed into New York harbor recently after a battle with a West Indian hurricane, in which she was wrecked on the Bahama reefs, shipping men characterized her as “‘the ship without a bottom.”’ Nearly every section of her steel bottom resembled the crumpled sole of an old shoe. Just enough of the under-water structure was left to keep the vessel afloat by means of compressed air. Money Used as Wallpaper ITH Austrian crown notes worth only three hundredths of a cent, money was the cheapest material this Ger- man could buy to paper his room. Euro- pean paper currency is so cheap that bills are even twisted into paper bags and some- times used for pipe-lighters.

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62 Popular Science M: onthly First the chunk of glass over 60 inches in diameter and weighing 200 pounds is ground to dimensions. It is then polished until every particle of foreign matter is re- moved from the surface. A thin coating of mercury is applied to the glass in much mirror from the glass form or mold and cover the silver surface with a lacquer to protect it from atmospheric conditions. This is done in a special room freed from all particles of floating dust. The metal mirror has a surface and re- Jul Violet s Detect the Invisible iolet Ray t N THE heart of a genuine pearl lies a mysterious, Under the invisible I unseen quality that gives the gem its warm mee i beauty and its value. What is it? How can this quality be detected so as to distinguish positively between the real pearl and the imitation? One way has been discovered—by the strange, invisible rays of ultra-violet light. The unseen is detected by the invisible. //gjies A pearl to be tested is held in the palm /4@ of the hand beneath the rays of a strong, bluish light. If it is a true gem, it seems to glow and burn as though it were painted with phos- phorus; while if it is artificial, the pearl appears to be dull black. To produce the peculiar effect, a light, rich in ultra-violet rays of long wave length, is required. The testing cabinet is a box Recently a small, compact mer- about three feet long, 16 inches cury-vapor light has been per- high, and 16 inches.broad. One fected. The lens of this lamp is end is open, except for a tight- made of quartz, which does not fitting black curtain. The other absorb ultra-violet rays. If ordi- end is pierced for the insertion of nary glass were used, all pearls the lamp, lens, and color filter. would look alike under the light. In the top of the box is a small A patented color filter made of Genuine pearls, tested under ultra-violet rays in slot, fitted with a mask. a nickel-oxide glass is mounted this cabinet, scl pon tig a uaa Artificial To test a suspected pearl, the over the quartz lens. This glass ° - jeweler thrusts his hand, holding absorbs almost all the visible light, while it eyes shine like a cat’s, and your teeth and the gem, through the curtain, and looks permits the longer ultra-violet rays to pass. finger nails glow; yet a porcelain filling in down into the miniature darkroom. If the If you look into the light when this filter your mouth will look black as coal. pearl is genuine, it will fluoresce with a soft, is in place, your eyes seem to be bathed It is this property—of causing fluor- bluish glow. with an invisible, balmy fluid. This sensa- escence in some objects, but not in others— It is said that many manufactured \ tion is the result of fluorescence of your’ that gives ultra-violet rays their value in gems, masquerading as the real thing, can eyeballs. Under the invisible light, your _ testing pearls. be detected by this method. od 4 ms Dri Huge Searchlight Mirrors from Molecules of Copper and Silver 28 po HEN huge mirrors, five feet in diam- trolled. Itis allowed to remainin thissolu- copper is deposited on the silver until the bw eter and perfectly formed, were tion until the molecules of silver have piled entire metal plating is .03 inches in thick- An needed recently as essential parts of army one upon the other to a depth of several ten _ ness. thi searchlights used in night signalling, thousandthsofaninch. It is then removed After the plating solutions have com- scientists found a way to manufacture the and thoroughly cleaned before immersion pleted their work the mirror is lifted to a mirrors in quantities without the employ- in another bath, this time of copper. The table. A plastic material is carefully ™ ment of large numbers of skilled opticians. neiiaaiamiaeine ; worked over the copper plating and later a , One glass form—made in reverse—beau- Pe BPE : : steel cap is placed on the hardened plastic iin tifully polished and ground is used as a | for the purpose of taking up the strains dur- f - mold on which to produce a multiplicity of ing handling and transportation. “a duplicate metal mirrors of high quality. The last process is to strip the final metal the same way that simple mirrors are made. flecting quality equal to the best glass mir- a. The mercury covered glass is then placed rors made. It has an additional advantage fe in a frame and lowered into a silver-plating in its ability to withstand hard usage with- G solution where the current is carefully con- out material damage. tl re) te p After passing through a silver-plating solution, the glass form is placed in a copper bath as shown above Above is the completed metal mirror, five feet in diameter, as used in an army searchlight fii) wae ee ite All Ge “i Oe sof a8 age WOE oat af aut a i-—___ 8: Strengthened by plastic material and a steel cap, the mirror is stripped from its glass form

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OX es ne it- er of ar, all he ng he ft, ed an k- The Fastest Things of Their Kind i in America! : on hundred miles an hour—more than three miles a minute—nearly 300 feet asecond! Measure that 300 feet with your eyes, then watch the little hand tick off one second, and you will have some idea of the fastest man-made thing in America. It is the triplane known as the Cactus Kiiten, with which Clarence Coombs took second prize at the Omaha air meet and in which he intends to try for the official world’s speed record this summer. To visualize the fastest man-made thing that travels on and not above the earth, imagine yourself whizzing over the hard sand at Daytona Beach, Florida, at the rate of three miles a minute. That’s the unof- ficial record set a few weeks ago by Sig Haugdahl in his Wisconsin Special racing car. He covered a mile in 19.97 seconds, or at the. rate of 180.27 miles an hour. The official world’s record is 159 miles an hour. The significant thing about these seem- ingly impossible feats is the fact that in each case careful streamlining and light- Driven by a 250 - horse- power hy- droplane motor, the fastest car in America traveled three miles a minute J, : ee weight, high-powered engines appear to have been responsible for them. Consider the Kitten, a triplane eight feet high and 231 inches long, with 20 foot wing spread. The total area of resistance of its stream- Even the radiator consists of streamlined piping carried behind the wings. tically no angle of incidence—that is, when the plane is trave!ing hori- lined fuselage is only 61% square feet! Where they would be at the end of an hour MOTOR BOAT —— TRAIN MAN § Miles 4 80.56 5 2l one hour Only 20 inches wide at the body’s widest point! Above is a_ rear view of Sig Haug- dahl’s air cutter at Daytona Beach, Florida. Note the long knifelike tail The wings have prac- ue ORCYCLE AUTOMOBILE * “AIROLANE 115.8 159 201 EIDERDOWN DUCK 227 Crossing the starting point ag oey and maintaining top speed for an hour, the record holding racers shown above would finish at the milestones indicated. When will a man-made machine overtake the eiderdown duck? zontally, they ride almost flat. They are supported on streamlined slab struts. The motor, turning at 2250 revolutions a min- ute, weighs only 700 pounds for 425 horse- power, or 1.61 pound to the horsepower. Similar streamlining principles are car- ried out in Haugdahl’s auto. The body of his car at the widest point is only 20 inches wide. The wind displacement is said to be less than one third that of any other ma- chine driven in world’s record speed trials. This knifelike speedster is driven by a six-cylinder motor that develops 250 horse- power, yet weighs only 600 pounds. With pointed == whirling nose and ies streamlined fusel- age, the Cactus Kitten’s total area of resistance is only6% square feet Medal-Making Machine Reproduces Finest Work of Artists A MACHINE that automatically repro- duces an artist’s bas-relief design to any scale without alteration of the slightest detail is responsible for the artistic per- fection of the latest coins and medals. Guided by soft wax forms, drills now eat their way into solid blocks of steel, turning out dies that are exact copies of the sculp- tor’s work—a thing that was virtually im- possible with hand die-cutting. The artist’s model, sculptured in wax or With a pantograph arm, details of the Ba ma a aa into a steel die wax mi reek age e - he «© ™e Blank medals are stamped from steel dies in this 500-ton press plaster, is fastened to a horizontal shaft on the cutting machine and a die blank of the softest steel is placed on a parallel shaft. Both revolve together at exactly the same speed. Between the model and the die runs a steel pantograph arm, carrying at one end a pointer resting against the model. At the other end is a small drill with a sharp point shaped like a four sided pyramid, resting against the die. Drill Cuts Replica in Steel As the pointer follows the curves and de- tails of the model, the weight of the steel arm forces the drill point into the steel, where it cuts out a reduced replica of the wax plaque. The steel die is then hardened and tempered, and placed beneath a 500- ton stamping pre s. The blank medal, punched from a sheet of bronze or silver, is placed between two dies and surrounded by an iron collar. The knuckle in the punch arm makes the dies first strike the medal and then press upon it. From three to twelve blows are neces- sary to reproduce all the details of the de- sign. As this pressure hardens the surface of the metal, the blank must be annealed between stampings to soften its surface.

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64 Inner Tubes Prevent Water Pipe Bursts IS a fact not always recognized that, when water-pipes burst, the damage is actually done at the time the water within them is ‘frozen. We only become aware of the burst when a thaw sets in and the pipe begins to leak. Beyond emptying all exposed pipes dur- ing, or in anticipation of, a hard frost, no satisfactory expedient has yet been devised for preventing these unfortunate accidents until this simple scientific device illus- trated was patented. When water changes to ice, its expansion exerts a pressure of fourteen tons to the square inch, but if an internal air space were provided throughout the length of an exposed pipe, it is clear that instead of bursting the pipe, expansion would take place internally by compressing the air in such aspace. The inventor’s idea is simply WIRE SUPPORT ware 7 RUBBER TU Internal expansion space in the ~“ is provided by a rubber air tube to insert a small watertight rubber air tube to provide such an expansion space. The method has been tested, with the fol- lowing results: Four short sections of or- dinary three-quarter-inch steel pipe were filled with water and sealed by means of stout pipe caps screwed on over the ends, small rubber tubes one eighth inch in diameter being inserted in two of them be- forehand. All four were then subjected to 14 degrees of frost until the water had frozen to a solid core of ice. Upon ex- amination it was found that, whereas the two pipes containing the air tubes were intact, the other two had burst for almost their full length—a fair proof of the effi- cacy of the inner tubes. BRITISH weavers have produced an artificial fabric said to be warm as wool, with the ap- pearance of silk. Fibers discarded in making artificial silk are spun into the product. Popular Science Monthly Race Horses Travel in Quiet Motor-Trucks When the horses are inside this box- stall truck, the sloping runways are raised to form the back and sides j ig ENGLAND, motor-trucks with special box-stall bodies are now being used to transport race horses from one track to another. It has been found that travel on railroad trains is extremely hard on the physical and ,nervous condition of a thoroughbred. Conditions met in a journey over a highway are less nerve-racking, and even after a long all-night ‘‘jump”’ the horses are in better condition for a race when they are carried by truck. Each carries two horses, which enter the stalls by the rear ramps and go out through the side doors. Mirror for Invalids Permits Shaving in Bed cy The mirror clamps on the patient’s knees Sixty-Five-Ton Rotor Rolled Ten Miles in Ten Days 52 OLLING a 65-ton dynamo rotor ten miles over the road to a power house proved to be easier than delivering it on a special truck. The grades over which the machine had to be hauled were as high as 10 per cent. It was found that two tractors could roll the rotor, while seven motor-trucks, in addition to two tractors, were required to draw a similar machine. The rotor was rolled by unwinding a double line of wire cables that were wrapped around the drum. This method applied the tractor’s hauling power at the circumference of the rotar instead of at the axle, thus producing maximum traffic efforts. — = © Engineering News-Record Seven trucks and two tractors were required to haul this rotor over grades Two tractors rolled a similar rotor by unwinding cables from the drum. ‘prone can now shave comfortably in bed, thanks to a new mirror that clamps on the patient’s knees and that may be easily adjusted. The mirror, an invention of Harry J. King, of Oaklandon, Ind., is supported by two L-shaped members working on a hinge at their junction, and padded at the lower end so that they may be clamped either to the bed or to the knees. The glass is attached by a universal joint to a rod sliding through the central hinge, and can be raised, lowered, or turned to either side, and held in the desired position by tighten- ing the wingnuts. The Banjo No Longer Speaks in Muffled Tones tT volume of tone from a banjo can be doubled, it is claimed, by a new sound- ing-board that collects the vibrations of the under side of the head and delivers them through a horn straight at ‘the audience. In most banjos only part of the possible tone volume is heard, as the instrument Horns double y the sound of banjos must be held close against the body of the player. In this way the vibrations of the under side of the head are usually muffled and lost. But in the new instrument this is prevented by a wooden back and a horn. As a special service to readers, the Editor will be glad to supply the names and addresses of manufac- turers of devices mentioned in Popular Science Monthly. oth in de\ ens to sh ser fiel lel tu ge: sp fie

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July, 1922 Iceberg Detector May Preven HEN great icebergs, break- ing away from the winter pack off Newfoundland, drift southward across the trans- atlantic steamship lanes, the sea captain is confronted with one of the most deadly perils of the sea. As his ship plunges through darkness and mist at 20 miles an hour, he anxiously peers into the gloom ahead, watching for the frosty gleam that may warn him, perhaps too late, of disaster. In the future, danger of such disaster may be eliminated by the use of a small parabolic mirror, recently invented, that detects icebergs six miles away by col- lecting radiations of infra-red rays. And, since fog is no bar- Tier to these rays, the new device may greatly reduce collisions. The parabolic gilded mirror, which is the chief part of the new instrument invented by M. A. Larigaldie, engineer and electrician of Paris, France, moves freely around a vertical element. 65 PARABOLIC ° oe Peas €—TELEPHONE - . RECEIVER: THERMO-ELECTRIC ELEMENT When the parabolic mirror points at an iceberg, infra- red radiations lessen the current in the thermo-electric This difference in current is detected in tele- phone receivers on the captain’s ears t Disasters at Sea axis, while at its focus is a sensi- . tive thermo-electric element. While infra-red rays, like the ultra-violet rays at the other end of the spectrum, are invisible, they affect the resistance of the thermal. element. Radiations from melting icebergs are spe- cially rich in infra-red rays. When the mirror points at a berg, the radiations will cause a marked change in the current flowing through the element. The difference is detected by telephone receivers on the cap- tain’s ears, and thus he may change his course in ample time to avoid a collision. It may soon be possible to utilize this instrument at night by sending out a powerful beam of ultra-red rays in the path of a ship, using a signaling tube de- veloped during the war. The beam will be reflected from any ship or berg in the vessel’s path, and the mirror will catch the warning. © K.& H. Gasoline-Electric Auto Simplifies Driving [ PFFERENTIALS, propeller shafts, friction clutches, speed gears, and other trouble makers have been eliminated in a gasoline-electric motor car, recently developed. The motive plant of the auto- mobile consists of a two-cylinder gasoline engine, the crankshaft of which is parallel to the front wheel axle. At each end of the shaft is a circular field magnet that also serves as a flywheel. The armature of each field magnet is in the form of a disk so mounted that it can rotate in a plane.paral- lel to that of its magnet. The two arma- tures transmit their motion to the driving gear of the front wheels by means of a sprocket chain. When the gasoline motor is started, the field magnets are set in rotation and the magnetic force, acting upon the armature 4 disks, causes them to rotate in the same direction, but with lesser speed. This difference between the speed of the magnets and that of their armatures introduces an element of elastic adjustment into the working of this type of propulsion. If the car, for example, travels uphill and, consequently greater power is required, the increasing drag on the armatures will cause them to rotate more slowly. But the in- crease in the difference of speed between magnets and armatures will automatically produce the generation of a stronger electric current. This is utilized for accelerating the gasoline engine and increasing the driving power of the armatures. The car runs with unusual smoothness. In the installation of the gasoline-electric engine, as pictured above, the crank- shaft is parallel to the front axle. Circular field magnets at each end of the shaft serve as flywheels. Armatures re- volved by the magnets trans- mit their motion to the front- wheel driving gear by a sprocket chain. At the right is a close-up of the engine dynamos Movie Camera Films Furnace Fire A photograph of the blazing furnace fire and the apparatus that took it MievENe pictures of a furnace fire photographed through a metal screen by Mr. Sanford Riley, of Worcester, Mass., have supplied new facts of what actually happens in mechanical stoking. As a re- sult, a mechanical stoker of twice the cus- tomary size, having a coal bed 20 feet in- stead of 10 feet long, may soon be com- mercially practicable. Intense heat was the greatest difficulty to overcome, for it cracked the camera lens repeatedly until protection was given by a device that might seem to make photog- raphy impossible. In front of the lens were placed two sheets of heat-resisting glass, with a single thickness of gold leaf between them. Gold leaf is opaque to the eye, but here it acted as a mirror that threw 75 per cent of the radiant heat back into the furnace and allowed about 75 per cent of the light from the blazing coals to pass through to the lens. This proved to be sufficient light for effective photography.

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66 Popular Science Monthly A Problem in Profitable Horse Trading Best Solution to This and Other Puzzles on This ra Will Win $25 in Prizes Count the Rectangles _ the glaziers had completed the windowin the professor’s new bunga- low, that astute gentleman contemplated the work, then spoke as follows: “In viewing your admirable artistry I perceive that within the large square formed by the boundary of the window there are 16 small squares, and that the dividing lines of the panes form an interest- ing variety of rectangles. Now, remember- ing that a square is always a rectangle, but that a rectangle is not always a square, how many different rectangles can be counted in this 16-pane window?” Let us figure it out for the professor. What Did the Squire Get for His Horses? Sy haps PERKINS says he has found it pays to figure horse deals in double trans- actions; that is, two horses, whether bought separately or =. together, always figure in his calculations. For example: The other day the Squire sold a pair of horses at auction, and when the auc- tioneer handed him a check for $493.68, the old horse trader remarked: “Not so bad, for while I have lost 10 per cent on one animal, I make 12 per cent on whole transaction.” for the horses separately? the other, thus clearing two per cent on the What did he receive How Many Bricks in Hod? "THE other day when a friend of mine encountered a man about to go aloft with a hod of bricks, he detained him long enough to gather some brick facts. When the workman was asked as to the weight of a brick, he replied: “A brick weighs three quarters of a brick and three quarters of a pound.” “Just so,’ assented my friend; ‘“‘and can you tell me how many bricks there are to the hod?” Then the fellow imparted some curi- ous information, as follows: “Half a hod and half a brick weigh 14 pounds less than three quarters of a hod plus three quarters of a brick.” Taking as a basis the workman’s strange figures for the weight of a single brick, how many bricks does the hod hold? June Puzzle Solutions THE COMET’S COURSE THE diagram illus- trates the course of Donati’s comet in 14 straight lines 4 which clear the M 4 field, and end with the large white Jt star. \ THE RAILWAY JUNCTIONS THE diagram illus- trates the method of laying the six tracks across the circle to produce 15 junctions, showing the limit of possibilities. SETTLING A STRIKE THE foreman received $1.10 the first day, then worked 90 days at $1.11, making 91 days for $101. Handy man worked 101 days for $101. Helper worked one day at 90 cents, then 110 days at 91 cents, making 111 days for $101. A FIRST prize of $10 will be awarded for the best set of answers and analyses covering the three problems on this page; a second prize of $5 for the next best set; and 10 prizes of $1 each for the 10 next best sets. Answers must be received not later than July 1, addressed to the Puzzle Editor, Popular Science Monthly, 225 West 39th St., New York, N. Y. Answers to the puzzles on this page will appear in the August issue; the names of prize-winners in Oetober. April Prize-Winners pas WINNERS in the April con- test are as follows: FIRST PRIZE, Ten Dollars: H.D. Clayton, Hill City, Kans. SECOND PRIZE, Five Dollars: Max Silverman, Ada, Ohio. The TEN One-Dollar Prizes: John Chincharick, Canon City, Colo.; T. P. Lyon, Fairhope, Ala.; Addie R.Vosburgh, Berkeley, Calif.; John Hier, Syracuse, N. Y.; W. D. Booker, Wawanesa, Man., Can- ada; H. E. Birkinsha, Elm Springs, Ark.; Alice Quillian, Greenville, Ala.; Rubin Atkin, N. Y. C.; Geo. H. Muller, Atlantic City, N.J.; J. F. Fonville, Jackson, Miss. Adjustable Set-Square Aids in Drawing Angles OR the mechanical draftsman a uni- versal adjustable set-square with which it is possible to draw lines at an angle much faster than when using a protractor, has recently been invented. The instrument is a celluloid 45-degree triangle, one face of which is in the form of a hinged blade equipped with a scale by which it can be set at any angle. The scale is a white celluloid arc with a transparent cursor. With the angle set, the instrument is moved in contact with a T-square Cr: from then cent that the pho’

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ly he ve July, 1922 Canteen Distills Breath A canteen that never goes dry has just been invented by Dr. Alexander Graham Bell, father of the telephone. Even in the desert or at sea the container will assure a constant supply of drinking water, it is said, for it distills moisture from human breath. The canteen consists of a glass tube and bottle. The wearer expels breath into the tube. Much of the moisture in the breath is condensed—as much as an ounce an hour, or more than enough to sustain life, says Doctor Bell. The water thus distilled is pure. Crane Lifts and Dumps Cars A crane that lifts a loaded coal car bodily from the tracks, weighs and dumps the coal, then returns the empty to the rails, has re- cently been built for use in industrial plants. Two steel tackles ending in double chains that are attached to the car just behind the axles handle the car as shown in the photograph at the right. Concrete Relayed By the use of a novel relay tower, the contractor for the North Avenue Bridge at Milwaukee, Wis., re- cently was enabled to place 17,000 cubic yards of concrete from one central mixing station. The mixture was started from the tower seen at the left in the photograph below, then hoisted to the top of the tower on the right, and distributed from that point through a swiveling spout. Nerves Treated on the Rack Stretching the backbone to relieve twitch- ing nerves and muscles while the patient is exposed to the curative effects of heat and light rays is a new method of treatment for nervous disorders developed by Dr. Jacob Rcemer, of Waukegan, Iil. The apparatus, shown above, consists of a cushioned table upon which the patient lies comfortably while straps are fastened about his head and feet. These straps are attached to rigid brackets sliding on a rod extending beneath the table. Stretching is accomplished by turning a crank that moves the brackets. The stretching is administered without jerks. Ifthe crank were turned rapidly and too far, the apparatus would become a “rack,” like the dreaded instrument of torture used during the Middle Ages. ‘Walker’? Mends Dog’s Back Even a broken back doesn’t prevent “Sandy,” a,full grown Airedale, from taking his daily stroll. When the dog was run down by an automobile in Philadelphia recently, the “walker” shown in the illustration was built to aid in his recovery. With his back in splints, “Sandy” is lashed to a framework set on rollers. This supports him as he walks. Linoleum on Street Strips of linoleum were laid re- cently on a busy street corner in Los Angeles to test the durability of the material. When the linoleum, shown below, was removed at the end of the day, it had not been ap- preciably damaged, although more than 15,000 vekicles had passed across it. This is said to be the equivalent of several years of wear. ~“ , $ Py eer a wa a 0 tgp,

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When in contact, the two measuring pins of this gage exactly equal the diameter of the standard cylinder. If the cylinder is over- size the space between the pins will indicate the excess Phe Seether mere Peet lia “ae This duster, suitable for garage or household use, slips on the hand like a mitten and will fit either hand. It keeps the hands perfectly clean and may be washed to remove accumulated dust and dirt Smokers owning closed cars will find this new ash-receiver, fitted on the instrument board, a great convenience. Normally the ash- door is closed and is opened by pressing a button Any number of chains may be placed on a truck whee! equipped with an iron ring fastened to the spokes and to which the chains are attached by stud links JACKING UP REAR WHEELS Road tests without taking your car from the garage can be made with this horsepower calculator —a frame placed under the rear wheels, which are set firmly against drums of two pony brakes. Dials record horse- power, speed, and gear ratio as the wheels revolve SPREADER AND LUBRICATING NIPPLE After the wedge of this device has been forced between er leaves of the auto- be mobile spring by turning a thumb- screw, oil is forced through a nipple -to a steel blade, which spreads the lubricant over the spring leaf To prevent theft of your spare tire, screw this safety device on the valve nipple, then turn the key of the lock attached to the cap As a special service to readers, the Editor will be glad to supply the names and addresses of manu- facturers of devices mentioned in POPULAR SCIENCE MONTHLY. Popular Science Monthly — Indoor Calculator Measures Power of Your Car Oil is one of the ene- mies of rubber tires and must be kept away from them. The motor - driven tire pump shown here is a diaphragm pump and hence requires no oil Pocket knives will not last long if used for setting spark plugs, scrap- ing off insulation, or removing car- bon. The tool shown above serves the purpose; the tip of its blade will set spark plug points - & ~ By jotting down every purchase of gasoline and oil, with date of purchase, on this disk recording device clamped to a spoke of the steering wheel, the auto owner can keep an accurate cost record This continuous tread of steel plates can be fastened around the drive wheels of a truck with- out injuring rubber tires Jul ae 2 a i a =

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Midget Washing Machine A complete breakfast may be cooked right at the table with this electric stove with three-heat control and uten- sils for broiling, boiling, toast- ing, and frying A gutter edge for the pie plate, as shown above, pre- vents juice from running over into the oven while a pie is being baked The bulge near the top of this coffee pot increases the diameter and cools the liquid before it can boil over In this compact, portable washing machine, the container (at left) is fastened to the plate (at right), which is tilted back and forth and around The alarm of this eight-day clock can be set 24 hours in advance. A signal (indicated by arrow) tells when the alarm will ring — eee Saves Space in Home To prevent slipping of rugs laid on polished floors, this netlike fabric, coated with rubber composition, is fast- ened to the under side by an electric motor A saucepan that won’t boil over! Water issuing through holes in the cover, which is locked well below the rim, runs back into the pan Contents of this sanitary food container are hermetically sealed by a tight cover with rubber gasket, that is held by an aluminum clamp With double walls between which cold air circulates, this container prevents wasteful melting of ice and keeps the refrigerator clean AS a special service to readers, the Editor will be glad to supply the names and ad- dresses of manufactur- ers of the new devices mentioned in POPULAR SCIENCE MONTHLY. The bacon frizzles while the water boils. This breakfast kettle is fitted with tubes through which heat passes to the frying pan above

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CRE geno eer tine A ip cee +e ae iatermrangnente ru

70 select blondes and others | es differ. Some men are carried away by bru- By Armstrong Perry Popular Science Monthly } My Ideal Radio Receiving Set How an Amateur, Advancing by Easy Stages from the Simplest Equipment, Planned the One Best Outfit to Meet His Needs the controls simple and give everybody instructions in the operation of the set.

nettes. Also, ideals change. The blonde may become first the wife and then the complainant, and the brunette may become the co-respondent. Just so, men are bound to change their minds in radio, ad- vancing from one conception of the ideal radio set to another, as the limitless possibilities of recre- ation, entertainment, instruc- tion, research, and _ financial profit through universal com- munication spread new vistas before them. The Beginner's Ideal Until quite recently the be- ginner’s ideal was to have a re- ceiver—any kind at all that would enable him to hear even one station. This usually meant a crystal detector, a loose coupler, a pair of phones and some wire. As I look back upon my own early experiences, I still feel that this as a first outfit is ideal for the man who lives in a town with a broadcasting sta- tion. Every one knows how much better it is to begin with a flivver than to climb trees with a limousine. My second ideal radio set was one that would tune more accurately than the first and thereby shut out the interference that sometiries prevented hearing the message I was fishing for with crude apparatus. Then I wanted one that was more sensitive, so that it would bring in messages from a greater distance. That meant vacuum tubes, grid leaks, condensers, verniers, and a lot of apparatus that a beginner might be able to use when it was properly adjusted, but that would confuse him hopelessly when things went wrong. After using such a highly developed re- ceiver long enough to master it, in the solitude and silence that are necessary when a man is taking his first steps in radio and

33 ae The Right Way This represents the kind of receiving set Armstrong Perry recommends as having all the advantages you will ulti- mately want. Note the tuner, capable of tuning in all waves between 200 and 25,000 meters; the radiofrequency amplifier at the extreme left, and the two stages of audio frequency with loudspeaker at the right needs to concentrate on every sound, he begins to realize that his hobby is a selfish one unless he shares it with the family. That requires the use of an amplifier and a loudspeaker, which will provide entertain- ment for a roomful of people. In removing the home receiving station from the den or other out-of-the-way corner in which it saw its early development, cer- tain adaptations must be made. Leakage of sulphuric acid solution from a storage battery is not serious on the rough board floor of the attic, but on a velvet carpet—! In the little old booby hatch the outfit could be loci.ed up to keep the kids away from it, but in the music-room even the smallest member of the family will want to show it off. The way of safety is to make No sooner is the outfit in- stalled permanently in the most favorable location than some one suggests radio music with meals. That requires an antenna con- nection in the dining-room, and, while we are about it, in various other rooms where the receiver might serve a useful purpose. The station becomes portable. A Portable Outfit Then, with the radio habit firmly fixed, there comes the summer vacation. Having en- joyed the privilege of listening in on the world while in town, we certainly do not want to miss it when we are out in the wilder- ness. Space in the car is limited. We cannot carry a radio receiver as large as a phonograph. An- other ideal is formed—a receiver that will be as efficient as the big one and as small as the little affair with which we started. All of these ideals are attain- able by easy stages and at ex- pense smaller than the tobacco bill of the average smoker. Some men will skip some of the stages of development. The cowboy on the plains, for example, has to begin with a highly efficient outfit, for a crystal detector will bring nothing to his isolated cabin but the bill, unless he be a genius. But any one, anywhere in the United States, can get what he wants by radio if his ideals are within reason and his persistence reasonably strong; a condition possible in no other country at present. The ideal complete outfit for 1 beginner consists of an antenna to pick up energy from the radio waves; a lead-in wire to carry the energy to the receiver; a protec- tive device to keep lightning from going in along the same path as the radio currents; a detector to change the radio currents to pulsations that will make sounds in the phones; a tuner to select the station he

R. PERRY’S “‘ideal’’ re- ceiving set that will bring you all the radio broadcasts you want to hear is described below. It consists of a tuning Circuit, one stage of high fre-

quency amplifi-

tor, and two stages of low frequency amplification. When the impulses strike the aerial, they pass downward to the variocoupler. From this they are led to a vacuum tube amplifier and its

These devices amplify only } the high frequency radio waves. After being ampli- fied, the signals pass to the detector tube, which detects them and alters their fre- quency to the audible fre- quency heard through the phones. By the insertion of

a variometer in the plate of the detector tube it is possible to lead some of the rectified

transformer.

VARIOCOUPLER | RADIO FREQUENCY VACUUM TUBE STORAGE VACUUM TUBE

TRANSFORMER AMPLIFIER BATTERY DETECTOR

| wants t« double | necting The < one. Fi wire ha about < elabora' should | the gro strung should possible Li Poree lators s ways 1 into tl lead-in or ana tion of carry ¢ put in electric these | surance agains’ antenr lead in ning s house The and if strand solid — which towar: loudly lead-it of the either equall For strong casts, A ma

curr furt! ing | tube are freq

Popular Science Monthly J

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ive the ne I least expense. going before you start. DN °T throw away money on your radio set. Don’t buy parts only to scrap them later. Don’t build up a receiving outfit that looks like a junk shop when completed. You want the best set you can get, at the You want it to be an attractive addition to the home, instead of an eyesore. Therefore, you want to know where you are You want a plan. Armstrong Perry, attempts to picture for you an ideal receiving set in its first, intermediate, and final forms. He shows how to plan your finished set intelli- gently from the beginning, getting the maxi- mum service out of your apparatus at each stage, always working toward the really complete radio receiver that will bring you everything going in the way of radio broadcasts. in this unique article, wants to hear; a single phone or double head set; and a wire con- necting with the earth. The antenna must be a good one. For receiving only, a single wire has always given me just about as good results as more elaborate aerials. The wire should be at least 30 feet. above the ground, and if it must be strung above a metal roof it should be as far above that as possible. Lightning Protection Porcelain or composition insu- lators serve as dams and sluice- ways to turn all the current into the receiver through the lead-in wire. A lightning switch or an arrester performs the func- tion of a floodgate or spillway to carry off any excess of current put into the wire by a heavy electrical discharge. Without these protective devices an in- surance policy does not insure against loss from lightning. The antenna wire is bare, but the lead in is heavily insulated from the light- ning switch to the receiver. It enters the house through a porcelain tube. The outside wires are large, about No. 14, and if they are made of seven or more strands they will bring in more energy than solid wires. The end of the antenna to which the lead-in wire is attached points toward the stations that will be heard most loudly, other things being equal. Or, if the lead-in wire is soldered to the exact middle of the antenna wire, stations pointed at by either end of the antenna will be heard equally well. For the beginner’s set in the town where strong stations transmit the daily broad- casts, the galena detector is the standard. A man in Texas says he hears a German The Wrong Way Here’s what your radio receiving station may look like if ou don’t visualize your final outfit from the very start. his station is, doubtless, highly efficient —but it is no ornament to the household. Compare its appearance with the attractive and compact receiving station that is il- lustrated on page 70 station just outside of Berlin, and scores of distant American stations, with a galena detector. My receiving range is shorter, but I hear concerts every day, church ser- vices on Sunday, and lectures and addresses often. Sometimes I listen in on airplanes in flight as they exchange messages with air stations on the ground.’ After making two adjustments I can go out for the evening and leave word for the other folks in the house to help themselves when the broad- casting program starts. Frequently I re- turn to find that they have enjoyed a good evening’s amusement while the fellow with the “good” station that I have been visiting has been telling me how clearly he heard KDKA week before last and what a corking show he could have given me “‘if the static had not been so bad,” and so on. Without a tuner of some sort no receiver is ideal, even for a beginner, unless he is interested in hearing only a very limited number of near-by stations. Tuners are divided into two gen- eral classes: short-wave and long-wave sets. Short-wave ap- paratus brings in messages from amateur stations and from the principal broadcasting stations. ’ Their tuning range is from 150 meters or less, up to perhaps 600 meters. Phones Influence Sound I have found the greatest sim- plicity and the highest efficiency in what is known as a single- circuit receiver using a variom- eter as the tuner. The type phones used makes a great differ- ence in the loudness of the music, voices, or signals as received. The best I have used are of a well-known type having mica diaphragms. On the other hand, I have experimented with a phone that sells at about 55 cents whole- sale and it brought in signals from one near-by station as loudly as the better phones for which I paid $12. For my ground wire I use a piece cut from the same coil as the antenna. Unlike the antenna, the ground wire need not be kept from contacts. The faster it leaks the current, the better it fulfills its purpose. In graduating from a crystal detector set to a vacuum tube receiver I began with an outfit using one tube only. Amplifiers come in separate cabinets that can be easily attached to the single-tube outfits, so there seems no more reason for starting with three tubes than there is for trying to juggle three baseballs before learning to catch one. current back to the grid to further strengthen the incom- ing waves. From the detector tube the strengthened signals are passed through an audio frequency transformer and a third tube, which again am- plifies the signal. The im- pulses from this tube are passed through another am- plifying transformer and through the second audio fre- quency tube. The signals are now many hundreds of times stronger than when received on the aerial —loud enough in most instances to operate loudspeaking instruments. In the sketch below B AUDIO FREQUENCY some of the stor- age batteries used to light the filaments of the vacuum tubes are omitted for the sake of clearness. Each tube must have current from a storage battery and also from a dry B bat- tery. EACH AMPLIFYING TUBE REQUIRES BATTERY CURRENT IST STAGE TRANSFORMER 2ND STAGE BATTERY le 1Q2? TRANSFORMER AMPLIFIER AMPLIFIER TUBE GROUND 4

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th aes is

Se ARS iat aS

’ Popular Science M onthly July, 1

VERY radio receiving set requires some type of antenna. While facili- ties are not always available to permit the erection of the very best type, still, there is always a one best method of antenna construction for re- ceiving under any The Five Best Ways to Erect an Aerial for Your Ideal Set The “indoor loop” can be used for ex- e perimental work or where the receiving set is located close to a broadcasting station. For medium distance reception a loop aerial must be used in conjunction with two or more stages of am-

given set of condi- tions. The accompany- ing diagram, show- ing five different types of aerial, will help you in plan- ning your own ideal set. The methods, as numbered, are: SS msc ro TALL it / This _ aerial e consists of a single vertical wire suspended along the side of a .

a wl

plification. Since a loop aeri- al receives best from directions in the vertical plane of its coil of wire, it is frequently used in preference to better aerials when it is desired to eliminate annoying interference.

The construc- e tion here em- bodies the most common and

house. It isatype that must perhaps the most successful type. be used where a roof or a ie re It consists of a single wire strung yard is not available. Ne | en between two supports with the

lead-in is attached at t e exact center. es lead-in wire taken from the end nearest the receiving set. This aerial is directive —that is, it will receive best from stations in the direction of the lead-in wire. This antenna is similar to No. 3, ex- ‘e cept that the lead-in is taken off at the midpoint of the aerial wire span. This aerial has a shorter wave length, but possesses the advantage of receiving equally well from all stations in line with the wire. Care should be taken that the Where a long span is not possible, or e where it is intended later to installa . transmitting set, a multi-wire aerial is preferable. This type consists of four or more wires strung between spreaders and separated for from two to three feet. All the wires are connected at one end and one wire is carried into the house. All types of aerials, excepting the indoor loop, should be suitably protected with approved lightning arresters.

The experimenter buys tubes, sockets, con- densers, inductance coils, panels, cabinets, and other items as separate parts and puts them together. Usually he puts them to- gether and takes them apart again many times an hour. But as my object was to hear something good and hear it through, I bought a receiver in which all the parts were permanently installed according to engineering data. There are many of these and a prospective purchaser can hardly go wrong if he deals with a reliable concern. Some receivers are advertised to tune from 150 to 375 meters, some from 150 to 3000 meters, and some are claimed to cover the entire tuning range of all the trans- mitting stations. My first vacuum tube set had a range of from 500 to 20,000 meters. I wanted to get the government stations, even the big fellows that shoot their streams of traffic across the oceans. Most of them work on wave lengths above 1000 meters, to obtain freedom from interference. It is doubtful whether any receiver de- signed to cover a large number of wave lengths is as efficient on all of them as a receiver designed to give maximum results

It Pays to Plan Your Set Or= Popular Science Monthly reader writes us: “In less than six months of radio experience I have bought one crystal set and scrapped it; one set of aerial equipment, which I foolishly scrapped for another; and one detector tube set, parts of which I gave away when I built my two-stage set. Also, I bought a lightning switch, and then scrapped it for a lightning arrester; and a loudspeaker, for which I soon substituted a phonograph attach- ment. ‘ “Now I have dismantled the whole thing, and am planning to assemble a new set, along the lines of the blue- print in Popular Science Monthly. This will involve the purchase of extras costing in the ndighborhood of $20. My scrapped material repre- sented a waste of at least $30.” —J.N. Armstrong Perry writes this article to help you avoid such experiences.

on a limited number of wave lengths within its more restricted range. There- fore, I would rather have a short-wave and a long-wave receiver than a single receiver designed to cover all wave lengths. I have worked with one kind that can be changed from a short-wave to a long-wave receiver by the simple process of pulling out small tuning coils and plugging in larger ones. The coils, known as “honeycomb” or “‘duo- lateral’ coils, are wound in compact shape with wires crossing and recrossing each other. The only adverse criticism I have heard about this type is that some of the very short coils do not function as well as the larger ones. The Advantage of Knobs Some receivers have more. knobs, switches, and handles on them than others. I have found that a reasonable number of controlling knobs is an advantage, though they puzzle a beginner. In making re- ceivers simple, some manufacturers have sacrificed efficiency. Success with highly sensitive vacuum tubes depends upon very careful adjustment of the current that lights the filaments, the current that elec- trifies the plates, and that which causes the grid to hold the reins on the other two. For a single tube, then, we need several knobs or switches. For very fine tuning appa- ratus we need at least two knobs. Some re- ceivers have as many as six of eight con- trols, which make the thing look very complicated; but it is easier to learn to operate them than it is to master the con- trols of the simplest automobile. The addition of an amplifier to the single- tube outfit is a simple matter. A one-step amplifier is supposed to multiply the strength of the sounds received by from 20 to 100. A two-step amplifier multiplies by another 20 or 100. The cost of the neat little cabinets is about $20 for each stage of amplification. Two stages are enough for average purposes.. My ultimate ideal receiver uses radio- frequency as well as audio-frequency am- plification. The former means amplifica- tion of the current before it passes from the antenna through the detector tube, and the latter means amplification afterward. Audio-frequency amplification is all right as far as it goes, but you cannot amplify

anything you haven’t got, and there area lot of little songs and voices that arrive at the door of your home so weakened by their long journey that they cannot push through the detector without a helping hand. The radio-frequency amplifier gives them strength to enter and then the audio frequency amplifier builds up their energy so that they sometimes swell out in louder volume than they did where they were born. Of loudspeakers—the devices that do for radio messages what the horn does for phonograph music—there are many. Some not only serve as megaphones, but also am- plify the sound by electrical devices. A number of them are but horns with ears to which the head phones can be clamped. None that I have heard deliver music of as good quality as I can get from a phono- graph. That quality which makes me for- get their imperfections is their ability to deliver fresh as well as canned music. When the vacuum tubes glow dimly and mysteri- ously through the red windows of their little cells, my imagination drifts easily to the opera or to the radio studio where cele- brated artists sing for me, their distant, (Continued on page 95) © U.&U.

CONDENSER ’ Loup SPEAKER - m) ay) Hy * BATTERY FOR VACUUM latisla “xt AMPLIFYING : oa TRANSFORMER _ PSaetee 2 RHEOSTAT MICROPHONE aol

This ‘‘talking valise,’’ invented by W. Dunmore, of the United States Bureau of Standards radio labora- tory, is a striking example of the compact simplicity and neatness obtainable in a radio receiving set when it has been __ intelligently planned and assembled

Sc F T } stat L in Church q sufficient Jackson, possible penitent church si Rev. M. port, he broadcas Sunday Harry L prison i wireless able to “lifers”’ tem. Radio ticularly port cht stance ¢ radio br of the e: section possible ing in d to atte Broade: music, church scattere ] The: Dodd’s slung | that a houses societie located ing pl power vacuur casting

ee 9 Aare FI EE ge i

Popular Science M. onthly ;

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i— Fo eee ie 7 SBS erTwrwht we Ss July, 1922 73 Radio Broadcasting Invades New Fields Scattered Thousands Hear Entire Church Services, while Voices from the Air Brighten the Days of “Lifers’ in Prison station recently installed in the First Baptist Church of Shreveport, La., had sufficient radio power to reach Jackson, Mich., it would be possible for 1800 convicts of a penitentiary to listen to entire church services. For while the Rev. M. E. Dodd, of Shreve- port, has arranged for the broadcasting by radio of all his Sunday sermons, Warden Harry L. Hulbert, of Jackson prison has made broadcasted wireless entertainment avail- able to his “time men” and “lifers’” under his honor sys- tem. Radio in churches is not par- ticularly new, but the Shreve- port church offers the first in- stance of an attempt to make radio broadcasts a regular part of the extension work. In that section of the country it is im- possible for many families liv- ing in distant outlying districts to attend church regularly. Broadcasted sermons, choir music, and chimes make the church services available to scattered thousands. 1500-Mile Radius The antenna of the Reverend Dodd’s church radio outfit is slung from a 10-story tower that adjoins the church and houses the various church societies. In this same tower is located the 200-watt generat- ing plant that supplies the power for the transmitting vacuum tubes. This broad- casting set, in charge of a I F THE radio broadcasting L The broadcasting station of the First Baptist Church, Shreve- La., showing the auditorium and tower;,with wiring, antenna, and generating plant. Inset —The pastor’s mother, port, At the end of the day, convicts in the Jackson, Mich., penitentiary listen to radio news and enter- tainment. Three receiving sets have been installed licensed commercial oper- ator, will have an outside radius of 1500 miles and will rank with the best stations in the South. Perhaps the most in- tensely interested of the radio audience is the pas- tor’s aged invalid mother, miles away in Trenton, Tenn. Until the installa- tion of the church radio set she had not heard her son preach for several in Tennessee, listening to her son’s sermon With wires strung above the roof, and a three stage amplifier receiving set, shown in the inset, this Philadelphia delivery truck picks up messages from its office, including instructions for last minute deliveries years, but now when Sunday comes around she can listen to his every word almost as clearly as if she were stiting before him in his church. Convicts ‘“‘Listen In” Eight hundred miles away from Shreveport, in the town of Jackson, Mich., is a colony of 1800 men whose only con- tacts with the outside world be- fore the coming of radio into their daily lives, were the infre- quent visitors and the still more infrequent letters. They are the inmates of Michigan’s “pen.” Impressed by the possibili- ties of radio as a means of brightening the days of his men, Warden Hulbert decided to install radio sets in the prison and its buildings. He placed‘ one outfit in the main prison, another at the brick- yards where hundreds of men labor under the honor system, and a third set at the clay pits where still other groups of trusties do their daily stint while working out their sen- tences. Now there’s radio news and enter- tainment within the dark gray walls and there’s radio on the farms and at the clay pits. Every evening this imprisoned ariny of men listens in on the outside world. Far removed from either of the two radio installations just described, but as interest- ing in its particular field, is the radio equipped delivery wagon of a Philadelphia bakery. The outfit consists of four wires spread on short masts over the top of the closed-in body. Taut anchors at all four corners pre- vent the wires from whipping in the wind when the truck is in motion. ' A lead-in carries the electric impulses through the roof of the truck and to the three-stage amplifier receiving set. A loudspeaking horn has been added for the purpose of entertaining customers en route. When the truck is on one of its trips, any official of the bakery can get into instant communication with the driver by calling up a Philadelphia broadcasting station and asking the radio operator to call the truck. Up to the pres- ent no transmitting equipment has been carried, hence the truck operator is unable to acknowledge the instructions by radio, but he can and does acknowledge them at the nearest phone booth. rae” pe aS ah gla aie Ae Pe

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on th Jack Binns broadcasts monthly the essential news of radio to the readers of Popular Science Monthly Who Will Invent a Radio Valve ?— line Squeals in room where I was snatching a hurried midday meal, a tall, angular, and somewhat nervous man sat down beside me with a tray of food. Just before he began to eat, he pulled out a daily paper, tore off the radio program, and began to study it intently. A little later, he looked up at me ner- vously, then ventured: “Have you got a radio set?” Before I could reply in the T'« other day, in a downtown lunch- e Cre Famous Writer on Radio How a Receiving Set May Become a Transmitter The Secret of Talking to Ships and Trains “‘When did he put his set in?” I inquired. “Oh, about the time I got the funny noise I was telling you about.”’ “Well, then, that accounts for your whistling noise,’’ I explained. “‘I’ll tell you just what happened. You know when the broadcasting station starts up, its trans- mitting set sends out a train of continuous waves. These waves act as a carrier for the voice currents, and they spread out in all directions, as long as the transmitting set Popular Science M. onthly : st of the Radio w—~ By Jack Binns VE ‘. America’s First Wireless Hero and Most ret Tuning A Great Chance for a Young Inventor Te foregoing paragraphs may explain to some of my readers one of the things which has been causing them trouble ever since they took up radio. The condition arises most frequently in larger cities, where, on some apartment-house roofs, you will see as many as_ seven or eight aerials attached to different affirmative, he continued: “T’ve got one. Made it my- self. I live in Boonton, and I’m ‘a fireman there. You know, it’s just a homemade affair. I get a lot of fun out of it. It’s just a crystal set. A Strange Whistle “The other day, though, I had a funny experience when I was listening in with a friend. I heard a peculiar kind of whistling that kept up a long time, going up and down the scale. The wind was blowing strong outside, and the other fellow said the whistling was the breeze blowing through the aerial. I told him I didn’t think so, but that the noise must be caused by sun spots, or else by Northern Lights. He wouldn’t believe me. “A few nights later the wind was blowing hard again. I listened in with the other fel- low, and we didn’t get that whistle at all. I said to him, ‘There you are, now. It isn’t the wind at all. It must have been Northern Lights.’ I guess I was right.” As he finished, the nervous man looked up with an air of triumph. “Well, that’s very interesting,” I said, and meant it, too, because I realized sud- denly how puzzling to many radio fans some of the common experiences of radio must be, and how erroneously these experi- ences are sometimes interpreted. Before my lunch-table acquaintance could say anything more, I asked him, “Is there anybody else in your neighbor- hood who has a wireless set?” “Oh, yes,” he replied, “‘there’s a fellow two blocks away who has a regular set, and he’s just put in two stages of amplification. It’s a regenerative set.” "6 station, with Thousands of students as far south as Florida and as far west as Wisconsin, heard college courses b when leading members of the faculty of Tufts College, Medford, lectures on their re Radio and Researc Hillside. table, reading his lecture isturned on. The chap who has a regener- ative set has the same kind of an apparatus, in a miniature form, as that in the broad- casting station. His set, when he turns it on, also becomes a small transmitting set, capable of sending out weak, continuous waves. In adjusting his set, he made it ‘heterodyne,’ or clash with the broadcasting station, and so caused it to squeal, or whistle. That was what you heard on your crystal set. Such noises occur every day, when a fellow puts too much current through the filament of his vacuum tube detector, in a regenerative set. It doesn’t help him, and it causes some interference to others around him.” “Gee,”” said my chance companion, “that’s the best explanation I’ve heard yet. You seem to know. You must be a wire- less man.” adio ass., recently volunteered to broadcast tive subjects from the American Corporation’s plant at Medford Four of the pioneer professors in this new enterprise of educating a whole countryside by radio from one omens are shown above, in the broadcasting ean Gardner C. Anthony seated at the sets in the apartments below. “How can a receiving set possibly become a transmitting set?”’ you ask, quite naturally. Waves from a Receiver The answer is simple enough. A regenerative receiver, in order to ‘‘feed back’’ energy and build up, or amplify, the weak incoming signal, causes the vacuum tube to oscillate. In other words, the receiver produces. oscillating magnetic waves, which will have the wave lengths of whatever par- ticular adjustment the receiv- ing set is tuned to at the mo- ment the vacuum tube begins to oscillate. Now if the receiving set ‘“‘heterodynes” upon the car- rier wave of the broadcasting station—I’ll explain that in a moment—there results a well- defined howl, or squeal, so familiar to the radio amateur, which will be recorded on all sets in the neighborhood, including the crystal detector sets. The heterodyning effect is caused in the following manner: In the first place, we know that the electromagnetic waves used in radio transmission and reception travel at the rate of 300,000,000 meters a second. Therefore, if we know the.wave length of a station sending out continuous waves, we _ shall know the rate at which they oscillate. For instance, the broadcasting station operating on a 360-meter wave will have a frequency of approximately 830,000. cycles a second. This is determined by dividing 300,000,000 (which is the speed of the waves) by 360 (which is the length of the waves). Now, when a receiving set is also oscillat- ing and sending out electromagnetic waves, it may happen that it will not be exactly | Re, a” | Se eS we an bet TO ee tot oh St

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llat- July, 1922 in phase with this frequency. In other words, suppose the receiving set were oscil- lating at 831,000 cycles a second. The re- sult would be that its waves, and those from the broadcasting station, would clash 1000 times every second; and vibrations at that rate produce a shrill noise that may cause inconvenient interference. This interference is an interesting prob- lem, and one that offers a big scope to the radio novice and amateur of inventive turn of mind. I was speaking about it the other day with John F. Grinan, one of the most famous of amateurs—the first man to send a message across the continent, and also the first to send across the Atlantic Ocean with ama- teur equipment. . “What is needed,” he said, ‘‘is a one-way repeater; something that will allow the incoming waves to pass down the aerial and be re- corded in the telephone re- ceivers, but that will pre- vent the local oscillations from getting to the aerial. In other words, what we want is a wireless valve. Here is a great chance for some young inventor, and I am quite sure he will come along, some day, and cash in on it.” So am I, Why Not Use the ‘‘Squeal’’? A YOUNG chap came to me the other day, and said: “There is always a terrific grinding noise in my telephones. I am using a regenerative vacuum tube set. I’ve tried to get rid of the noise, but without success. All the sets I have listened to have the same trouble.” - I am mentioning this because I have found the “grinding noise” is a source of trouble to most novices who have regenera- tive sets. They become discouraged, and because every one else they know is experi- encing the same difficulty, they feel the trouble is inherent in that particular type of apparatus. Foreign Noises Are Unnecessary As a matter of fact, any extraneous noise in the telephones is unnecessary with a set of this kind—except in the case of the poor unfortunate who lives next door to an am- bitious amateur with a one-kilowatt trans- mitter, who believes the ether was created for his own particular enjoyment. When the noise is of the “‘grinding’’ or “frying’’ type, usually the trouble can be found in loose connections. Don’t take anything for granted. You may feel sure that all your connections are securely made, but don’t rely on your feelings. Make sure that each connecting wire is tightly screwed to its terminal. If you find the wires are secure, yet you still get those grinding noises, the trouble must lie in your B battery, in which case I would suggest that you buy a new one. By the way, when I said, ‘‘Look over your con- nections.” I referred also to those inside the cabinet. There is another noise that is probably more frequent in regenerative sets. That is the “howling” or ‘squealing’ noise. In- The train’s radio equipment was a six-wire, 41-inch aerial, 18 inches above the car, connected with a two- step receiving set. The transmitting equipment was a set with a maximum radius of 50 miles. Reception and transmission under normal conditions were said variably this is due to the manipulation of the set by the novice. If you pass too much current through the detector and amplifier vacuum tubes, you will always get howling, or squealing. This brings me to an important tip. It is important enough to merit a paragraph to itself: Music and speech are received most strongly and most clearly at the adjustment JUST BELOW the squealing or hissing point of your set. Don’t forget that. . Here is another important thing to r member: If your set has a “‘vernier’’ ad- 75 being prosecuted. These experiments have to do with the application of radiotele- phony to the ordinary pursuits of man, in business as well as in pleasure. Inventors have already developed a sys- tem whereby the radiotelephone can be connected with the ordinary telephone lines, so that a person may sit at ease in his home or in his office and communicate with a passenger on aship at sea. This system is: now being applied to moving trains and to aircraft flying between cities. The great difficulty, however, has been to devise a system whereby one speaker can interrupt the other and stop a communica- to be almost perfect justment handle, you can eliminate all hiss- ing and squealing by carefully and very slowly adjusting this handle until the hiss- ing disappears. — One of the peculiar things you will ex- perience about the hissing is this: If you turn the vernier handle around, you will find that the hissing varies in its tone. In other words, it will start from the bottom and go up to the top of the scale. Then it will stop, and a little farther on will start from the top of the scale and go down to the bottom. The point to aim for in the re- ception of music and speech is the point be- tween the time the hissing reaches the top of the scale and the time it starts to descend. This is the best adjustment you can get, andit is known as the critical point. Another thing: On your detector B bat- tery, don’t forget that all vacuum tubes are not alike, and some require less plate voltage than others. Therefore, so far as the detector tube is concerned, it is bet- ter to put in a variable B battery, so that you can take off taps from different volt- ages below 2214 volts. This is not neces- sary for the amplifier tubes. How You Can Phone to a Friend at Sea © At THE present moment, when the genius of the country is concentrated upon the development of radio receiving apparatus to improve the concerts that nightly are being sent through the air, a set of experiments equally important is During recent tests in which a speeding Lacka- wanna express train kept in touch by radiotele- phonewith stations miles away, an stern rail- road demonstrated that a train, in a long tunnel, could receive messages almost as clearly as in the open. Operators are shown below receiving and sending messages in the buffet car tion which isnot being understood, without requiring the radio central to throw over a switch from the transmitting apparatus to the receiving apparatus. This is a difficult and serious problem. The chief difficulty lies in the fact that at the radio central sta- tion the transmitting apparatus is sending out a tremendous amount of power from the aerial wires, sufficient to communicate five or six hundred miles, under the most ad- verse conditions. The amount of energy received from the distant station on the same aerial is infinitesimal—in fact, it is so small that there are no measuring instru- ments known to man sufficiently sensitive to measure the amount of current. One Problem Partly Soloed From this, you may readily understand how great is the problem of making this minute incoming current interrupt and stop the powerful current that is being sent out from the same aerial. The problem has been solved to a certain extent in two differ- ent ways, both of which are based on the same general principle. One of these methods was used in the tests recently carried on between an ex- perimental station in New Jersey and the steamship America at sea. It consisted of establishing the transmitting station in one locality and the receiving station a few miles away. But even with the stations this far apart, the radiated energy from the transmitting station is impressed upon the receiving antenna with great intensity. The method of enabling the weak incoming signal to stop the powerful outgoing voice

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ee eT eae Ie PRE ast ge Say, CPLR ENE

76 is by balancing the transmitting against the receiving circuit. Included in this balance is the land line circuit connected with the radio circuit. The other solution is to divide the an- tenna at the radio central into two sections —one for receiving and one for transmit- ting, and then to utilize the balancing ar- rangement in the same manner. This balancing is controlled by a coil, which has been named the “‘hybrid”’ coil. As a result of the radiotelephone tests with the America, many of our radio novices stuck their chests out with pride, because of the great distances from which they im- agined they had heard signals. They all distinctly heard the experimenter on the America announce that he was 800 miles from shore. In fact, they heard him each night of the tests—that is, they thought they heard him. As a matter of fact, what they actually received was a re-radiation of his remarks from the transmitting station at Deal Beach, New Jersey. The manner in which this re-radiation occurred was as follows: Incoming Current “Spills Over’’ The “hybrid” coil, not having been ad- justed 100 per cent perfect, permitted a slight amount of the incoming current to “spill over” into the transmitting side of the balance. The consequence was that this excess amount of current passed through the amplifiers in the transmitting station, thence through the oscillator, and finally radiated from the aerial. What the novice received was this re-radiation. So far, this balancing method has been very successful in communicating with ships at sea and with aircraft, but it has not yet been applied to moving trains. Direct two-way conversation between moving trains and stationary points is still a thing of the future. However, an inter- esting result of recent tests with radio on the trains of the Lackawanna Railroad is the confirmation of many theories in con- nection with certain directional effects of aerials. The tests also demonstrated the ultra-sensitiveness of the vacuum tube asa detector and amplifier, for speech was readily received while the train was inside a 4283-foot tunnel and also while it was underneath the steel-enclosed terminal in Hoboken, N. J. In perfecting radiotele- phone communication with moving trains,

Popular Science Monthly

How a Two-Way Radio Talk Is Possible

Y USING the well known principle of the Wheatstone bridge, illustrated in the accompanying dia- gram, radio. engi- neers recently were able to carry on a two-way conversa- tion by wireless telephone with the steamship America, 400 miles at sea. The ship was picked up by radio operators at Deal Beach and Elberon, N.J., where wires from the land phones were joined to the radio equipment. Complicated wir- ing and many sen- sitive instruments

a hme

niall RECEIVING STATION TO ! LAND PHONES LAND PHONE

TRANSMITTING STATION

were employed in the ship - to - shore coil” and a “balancing network.”’ another, just as over the ordinary phone.

demonstration, chief among them being a “hybrid ‘ These are not needed for one-way radiotelephony. Any person on shore, for instance, might have phoned to a radio transmitting station and there had his speech conveyed via wireless to the America. But to be a success, ship-to-shore telephony must permit the two speakers to talk as naturally as if they were face to face, and to break in on one When such a two-way conversation is attempted, some method must be found to prevent the tremen- dously heavy currents of the radio transmitting station from working back to the land phone. The hybrid coil and balancing network, which accomplish this, consist of an arrangement of coils and condensers that filter out the undesired electric impulses and allow the essential ones to pass. When the balance‘is perfect, the trans-

mitting station can send the speaker’s words through the air with as high a power as is neces- sary, without its working back to affect the operation of the land phone. This makes uninterrupted conversation possible.

one of the problems that wireless engineers must contend withis that of “radio pockets.” It has been known for some time that mountain ranges form a very strong screen to electromagnetic waves, and that on the opposite side of these mountain ranges there exists for a certain distance a wireless “pocket,” in exactly the same manner as there would be a “pocket” of calm air on one side of the mountain if a terrific wind were blowing straight at the mountain from the other side. As in the case of the wind, however, this “‘pocket” extends only as far to the rear of the mountain as the shield- ing effect exerts its influence, The diffrac- tion of the electromagnetic waves permits them to come together in the rear of the mountain and carry on to infinity, leaving only a small “pocket” in which there can be no reception.

Five-Ton

(KOMPLETE equip- ment for highway maintenance has just been designed by Stan- ley Able, of Kern County, Calif., in such a compact form that it can be carried upon a single five-ton truck. The unit carries ma- chinery and _ supplies for practically all va- rieties of road repairs. It will repair bridges, erect fences, put out fires, and fix breaks in any sort of road sur- face, whether of con- crete, reenforced con- crete, or macadam. The important parts of the equipment are a

material bin, holding cement, rock, and sand, plow, How the repair equipment, including concrete mixer,

wer winch, gradi ot-tar sprayer, and material bin, is assembled on the truck ad Truck Carries Complete Road Repair Equipment and a small concrete mixer complete, even to the water tank. There is an air com- pressor to operate the sprayer, a power winch, a grading plow, a spray paint outfit, a hot-tar spraying device, an oxyacetylene cutting and welding outfit, and a post-hole digger. Power for all these tools—eight in all— is derived from the truck éngine, and no auxiliary motor is carried. The power shafts are rotated at various speeds, accord- ing to the tool being used, by seven-speed compound _ transmis- sion controls.

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‘July, 1922 How | Earn — Money Making Socket Wrenches The Story of a Mechanic Who Is Turning His Skill with Tools to Spare-Time Profits in a Novel Way HE writer of this article, which wins first prize in the contest, “How I Made Money with My Tools,’’ estimates that he has earned about $400 from a year’s sale of the wrenches he makes in odd moments. To wrestling fans in Minnesota, North Dakota, Wis- consin, Iowa, and Nebraska he is known as Peter Petkoff, ‘‘the Bulgarian wonder.” He was born in Bulgaria in 1894, had the equivalent of an eighth-grade educa- tion in the town of Ruscuk, and was brought by his father to the United States when he was 13 years old. Peter Petkoff Wrestling Wrench-Maker Wins in Tool Contest “The balance of my education,’ Mr. Petkoff writes, “has been picked up here and there through observation, including my knowledge of the English language, of which I knew nothing when I landed in New York. “My first employment was in a foundry at Pittsburgh, where they almost worked me to death. From there I took a long jump, going to Duluth, Minn., where I worked for transportation companies, railroad and steamship, in different labor- ing capacities. In 1917 I met an attorney who advised me to go into the automobile business and I have been at the mechanical end of the business ever since. I went into the industrial army during the war and helped build gas, electric, and steam hoisting engines. In 1920 I went to work for the Payne Motor Co., Minneapolis, Minn., where I am still working and still making wrenches in my spare moments.” By Peter Petkoff Winner of First Prize in Contest, ‘‘How I Made Money with My Tools’’ AM an auto mechanic who never had l much patience in wrestling with the nuts and cap screws hidden away in so many mean places around the average ma- chine. So I started to make wrenches that would get into the out-of-the-way parts with @ase—wrenches that would turn corners. After I had made a set of the wrenches, _ the boys in the shop saw how they worked and the time and effort they saved. They promptly asked me to make some of the wrenches for them. This I did, and soon found myself making an average of three a week. On the photograph I have numbered the wrenches from 1 to 18—an unlucky num- ber, but I am not superstitious! The socket of wrench No. 1 was made from a wristpin, while those I am now making are from wrenches of a certain brand that are the best on the market, so far as I know, from which one can make a universal-joint socket wrench. Making sockets out of wristpins takes up much more time than buying the readymade sockets at 38 cents apiece and cutting them up. I am, therefore, really making more wrenches and more money by my present method. The other parts I use for a wrench like No. 1 are as follows: a piece of 7/16-in. square key steel for the joint block; a piece of §& by 1% in. round tool steel for the joint between shank and handle; a piece of 7/16 by 12 in. cold rolled iron for the shank; a discarded oil-pump plunger, already drilled, for the top of the shank; and a piece of 14 by 5 in. cold rolled iron for the handle. The joint block, shank and handle are pinned through with 5/32-in. drill rods, five pins in all being required for the job. The explanation of the wrenches and parts on the photograph is as follows: 1. A wristpin socket wrench for a \-in. cap screw. 2. A \%-in. wrench with joint block of 7/16-in. key steel. 3. A %-in. wrench for spring clip nuts made from two T-handle wrenches. 4. A %-in. cap screw wrench which has a double-jointed universal socket and is in- tended for getting around corners. Two wristpins are required for this. 5. A %&-in. wrench made from a dis- carded pp plunger. 6. A 3%-in. cap screw wrench made from a commercial wrench, with an old oil-pump plunger for the top of the shank, % by 5% in. cold rolled iron for the handle. 7. A 5/16-in. wrench for cap screws. 8. A 3/16-in. wrench for couplings. 9. Wrench made from a wristpin. The sockets are formed by putting two or three nuts of the desired size on a stud or cap screw. After the wristpin has been heated, the nuts are«driven in and the outside of the socket end is hammered all around. 10. A commercial wrench cut for a uni- versal 5/16-in. capscrew wrench. 11. An oil-pump plunger, showing where it is cut for use as part of wrench No. 5. 12. A %%-in. joint block. 13. A 5/16-in. socket, from the joint side. 1 , J) : " FS ) a 8 10. a ° Socket wrenches for automobile repairmen made by Mr. Petkoff. Number 4 has a double universal joint to permit tightening cap screws in inaccessible corners

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78 Originality Marks the Prize- Winning Contributions for July ‘THE outstanding feature of the three prize-winning contributions in the contest, ““How I Made Money with My Tools,” is their originality. None of the writers is following ordinary methods in earning extra money with his tools. And just as unmistakably the work of each man shows him to be gifted with excep- Blacksmith fissiae By D. J. Popular Science Monthly Miniature Portraits Spencer (Second Prize, ‘‘How I Made Money with My Tools’? Contest) and until a year ago last September I never had time to indulge my great desire to carve. Being out of a jobfora few days, I began carving a small sparrow- hawk, then an eagle, then a group of four eagles, called the “Feast of the Eagles.” I HAVE been a blacksmith for 41 years Most of this work hasbeen done at night and for the love of it, although I find ready sale for the carvings, and have picked up a tidy little extra income from them. Among the compositions I have at- tempted is a mother and child carved from a single piece of wood about 5by 6in. The tional mechanical ability. The majority of letters submitted told how the writers are making money in many varied but more usual ways, and the best of these will be published in following num- bers of POPULAR SCIENCE MONTHLY. How to Build a Radio-Phone Set into a Library Table By Neal W. Sanders OR one of the boys in a sanitorium who had but limited space in his bungalow, I made the library table for a radio set as shown in the accompanying illustration. The top is 24 by 30 in. and the legs 2 in. square and 29 in. long. The top is in two pieces, the back being fastened solidly to the rails and the front hinged. The base of the instrument panel is also hinged at the back so that it may be Next I carved the figure of our old dog. The work must have seemed realistic, for every one was so ap- preciative that I felt encouraged to. at- tempt miniature por- trait work. My first study was a small head of the immortal Lincoln. Then I carved the then Presi- dent Wilson and sev- eral local residents, and made a few ani- mal studies. Among the latter was a lion carved from _ coal, which weighed ap- proximately 400 pounds. I have carved more than 220 pieces. To > Character study of a neighbor carved in wood and gilded mother is sitting in a rocking-chair with her baby’s head on her bosom. Another sub- ject, in stone 5 by 9 in., is a pioneer rising from his blankets with his gun in hand and two alert dogs at the foot of the bed. The way to do this work, I find, is to vis- ualize some object in the rough block and then make the hand cut away the outside until the form is re- vealed. Study for power, poise, and pro- portion. If you are carving, do not model in wax or clay; the two processes, to my mind, are the antithe- RADIO PANEL - When not in use, the pan the table top, as shown i a2 ” On Ss ij a) = 3 Q. @ = show that fine tools were not necessary, I carved one Lincoln out of what is known as Utah mahogany about one quarter life size with a three- pound hand ax, never touching the wood with another tool. The offer of $50 for this bust which I refused shows the scale of my profits from this work. Life-size portraits of Lincoln, Washing- ton, and Okuma, late Japanese Premier, were carved in Utah ruby sandstone. The head of Okuma took 23 hours to complete. One of his fellow countrymen who knew him well said it was an excellent likeness. sis of each other, and carving is the greater art. Study means of expression by carving soft substances. I gave a dinner recently and the baked potatoes were each a miniature of a char- acter from the comic papers. Although I liked to make pencil sketches when a boy, I had no training in art. In fact, I never saw any woodcarving—except the old-fashioned Indian standing watch in front of a cigar store—but in my visits to art museums I have seen the work in stone and bronze of some of the recognized masters. Turns Sculptor after JITHOUT Lifetime at the Forge such indirect method; he carves from the lowered out of the way or raised for opera- tion. When the panel is dropped beneath the table, the table-top is entirely clear and can be used for its ordinary purposes. The edge of the base, it will be seen, then makes part of the top. When the panel is on the table in place for receiving, the 7%-in. space between the two halves of the table top permits the wires from the A and B batteries to come up from the back, thus keeping them neatly out of sight. By tacking a 6 by 8 in. board flush under- neath the top at the back, a shelf is made for the B battery. Removing Borings with a Magnetic File [x CASE a drill is not long enough to carry the borings out of a deep hole, they may be removed easily by inserting a magnet- ized rattail file into the hole. The file can be magnetized by placing it on the face of a magnetic lathe chuck or on the field of a generator for ten minutes. It will hold its magnetic power for several days. I used this method successfully in clean- ing out the holes bored in some very heavy steel rods.—A. E. SMITH. 80 ever hav- ing read a book on carving or taken a lesson in art, Mr.D.J. Spencer, of Price, Utah, who has spent a lifetime at the forge, turn- ed his hand to sculpture in September, 1920. He is now’ working on a series of portrait busts of famous men, and has carved Lincoln, Washington, Jefferson, Roosevelt, Wilson, President Harding, and Venizelos. The fact that Mr. Spencer makes no preliminary studies in clay or wax gives his work an unusually interesting aspect from a technical standpoint. The usual method of carving any hard substance, whether stone or wood, is first to make a model in plastic material, then a plaster cast, and finally, by more or less mechan- ical measurements, a carving that may or may not be touched up freehand by the original sculptor. Mr. Spencer follows no D. J. Spencer with study of Venizelos block freehand, with nothing to guide him but his eye, and uses the ordinary tools that can be found in any average home workshop. This simplifies his work so that he can carve with comparative rapid- ity and therefore earn more than would be possible if the slower, more roundabout process were used. His ability with tools is reflected in his success as a_ blacksmith. Some of the records he holds have rarely been equalled. Last summer he is said to have sharpened 240 cutter bits in one hour and he has done 1600 in eight hours, day in and day out, as ccmpa-ed with the average smith’s rate of from 400 to 600 a day. In his time he has shod more than 45,000 horses. Mr. Spencer has an enviable ancestral record; he comes from old Revolution- ary stock; his great-grandfather fought through the Revolution; his grandfather fought in the War of 1812, the second Seminole Indian War, the second Black Hawk War, and the Mexican War; his father in the Civil War. Born in 1865, .Mr. Spencer put in brief terms of schooling in West Virginia and in Indiana, and for a time attended the Western Normal Col- lege, Bushnell, Ill. He has been married 31 years and has three children and one grandchild. (| a eS Orv¢L I = a an fa Popular Scvence Monthly "

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ee ee eS ee July, 1922 Indoor Loop Aerial Helps Overcome Summer Static By George A. McHenry gra the bane of summertime radio- telephone reception, may be overcome in large part by the use of a simple loop aerial in place of the ordinary outdoor antenna. It will not, however, serve well with a crystal set; a good vacuum tube receiver with several steps of amplification is essential for the best results. For making the loop aerial two pieces of wood % by 1% in. by 4 ft. 6 in., four pieces % by 1% in. by 8 in., 100 ft. of No. 18 cotton covered wire, 12 screws and 2 bind- ing posts will be necessary. A base or sup- port of some kind will also have to be con- structed to permit the loop to revolve around its vertical axis, because this type This aerial takes the place of oute door ane tenna 8 FULL TURNS NE 1B C.C. WIRE of aerial is highly directive and should be turned so that its horizontal axis points in the direction of the transmitting station. Assemble the frame as shown and wind on eight full turns of the wire, spacing the turns 34 in. apart. Connect the ends with binding posts, from whieh run wires to the aerial and ground posts of the receiving set. Even better results will be obtained if the loop aerial is connected only with the aerial binding post and a regular ground connection made with the ground terminal of the set. The adjustment of the set may be made more delicate by taking taps off each turn of the loop aerial to permit the regulation of its inductive value and by shunting a variable condenser of .0006 microfarad maximum capacity across the active turns. The advantages of the loop aerial in over- coming static disturbances, in reducing the interference of other stations to a minimum, and in making unnecessary the cumbersome outdoor antenna, are obvious. On the other hand, reception with a loop is not possible for as great a distance as with an outdoor aerial, and a more elaborate set is required, adding to the first cost of the installation and its subsequent upkeep. Motor Brush Cleans Typewriters ‘T typewriters used in a shipping office over a large warehouse were in almost constant need of cleaning, especially in the summer, until a special machine method of brushing them off was adopted. The cleaning was done by means of a small circular brush mounted on a flexible shaft connected with an electric motor, which would be plugged in the nearest light socket. This eliminated the drudgery of hand dusting, saved time, and reduced repair billa.—-DALeE R. VAN Horn. July, 1922 79 Bench Talks Making Your Home Workshop Pay Large Dividends By Arthur Wakeling D- aghconarieaha who had the privilege that has just been mine, of reading hun- dreds of manuscripts subrhitted by readers of PoPULAR SCIENCE MONTHLY in the Home Workshop’s “How I Made Money with My Tools” contest, would be amazed at the variety of ways in which mechanical hobbies may be made to pay cash divi- dends. I had always assumed that most men who work at home with tools do so because they find it a mint of fun and recreation, with by-product savings in bills for up- keep, repairs, and new furniture. But the readers’ letters that I have just read con- vince me that the average home workshop, and the hours of healthful amusement spent in it, can be turned into nice little cash profits by the enterprising tool user. Some of the contestants even built their own homes as the direct result of the experi- ence and confidence they had gained in their work with tools. One of them, who put up a house chiefly with the aid of his wife, is a clerk and never worked at a building trade. Others turned their efforts toward remodeiing old places they had purchased at comparatively small cost. Selling Home Workshop Products The larger number of writers told illum- inating and most encouraging stories of how they had added to their income by making things in their spare time. The product of their workshops range all the way from automobile bodies to xylophones. Many found profitable and ready sale for special furniture, toy furniture, toys of all kinds—wood, metal, and electrical; novelties, electrical devices, tools, models, objects of art, wood turnings and carvings, craft work, ornamental metalwork, jewelry, and an infinite variety of other products of the home workshop. Repair Work Proves Profitable Numbers of others made extra money with repair work of one kind and another. One [man made a specialty of replacing worn automobile runningboards; another bought second-hand gas engines, repaired and painted them, and resold them at a‘ profit; a third bought and overhauled electric motors, selling them to such ad- vantage that he was able to equip the second floor of his garage with a consider- able assortment of machine tools and woodworking machinery. Repairing furni- ture and upholstery, fixing broken toys, and mending electrical appliances are the spare-time occupations of other home workers. Among all the contributions to the con- test, no two were exactly alike. Their diversity proved that the home workshop can save and earn money in countless ways if ingenuity is combined with persevérance and if the right market is found. Many of the most interesting letters will ap- pear in following issues of POPULAR SCIENCE MONTHLY. Watch for them all. They will bring you inspiration, amuse- ment, and helpful suggestions that you may turn to your ow' profit. Celebrate a Safe Fourth with Carbide Cannon By A. L. Long we in plenty for celebrating the Fourth of July can be made with an electric carbide cannon. Not only is sucha cannon safe, but the ammunition costs next to nothing, is easily obtainable, and pro- duces a surprising volume of sound. The most expensive part of the cannon is the coil. The one used in making the can- non illustrated is a Ford coil, and any Ford owner can readily borrow a coil from his machine when the cannon is to be used. Dealers in second-hand auto accessories usually have old Ford coils at a reasonable price. The gun carriage is a wooden box for holding the coil and dry cells mounted on two wooden wheels. A syrup can 34 in. in diameter and 4 in. high should be mounted as shown with wood screws and a bolt run through the front of the box to a brass tongue for making the ground connection. A spark plug is screwed into the upper part of the can and connected with the coil as indicated. The tight fitting can cover is tied to the gun carriage with heavy fishline or strong cord so that the explosion will not blow it into space. Provide a small oilcan to contain the water used in charging the cannon. To charge, release the back rest and allow the cannon to swing muzzle up. Place from six to eight grains of pea carbide in the can and moisten it with several drops of water from the oilcan. The gas will form imme- diately, so push down the lid tightly at once. Fire the cannon from a distance by BRASS TONGUES i }) stRPLE ORWEN Bo - TH Hm LI y HEAVY An electric spark fires this noisemaker pressing a pushbutton at the end of a flex- ible lamp cord. The report will be equal to any cannon cracker on the market. Several explosions may be obtained from one charge if water is added each time. As soon as the carbide appears to have become powdered, clean out the can and recharge with new carbide. Fifteen cents’ worth will be enough for an all day’s celebration. The cannon will be more realistic if painted to look like a miniature piece of artillery. With a little ingenuity, coast or railroad artillery pieces may be imitated. 81 $ BRAC eee me a at nA nae eR EO er Deere =

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80 Clock Turns Off Store Window Lights , By Edward Jones (Third Prize, ‘‘How I Made Money with My Tools’? Contest) AM clerk for a hardware dealer who closes his store at 6 P.M., except on Saturdays. My employer made the remark one day that it would be good advertising to leave the show window lights on until 9:30 or 10 P.M., but this would mean that one of us would have to return to the store to switch off the lights at that time. I offered to construct a time switch for him if he furnished the material. To make the apparatus I used an ordi- nary one-day alarm clock, one dry cell, an electromagnet, spring, switch contacts, and a few odds and ends. I removed the alarm mechanism from the clock, using the cam of the time mechanism, which sets off the alarm for operating the switch circuit. I made a contact to work in connection with this cam, and insulated it from the clock mechanism. A wire from this contact is connected with the battery, and the circuit then runs from the battery to the lower switch, from that switch to the electro- magnet, from the electromagnet to the clock, where it is grounded. The lower switch is necessary to save the battery. A lamp cord is secured to the upper switch and passed through the side of the case. A composition bushing is used in the side of the case as a finishing touch as well as for safety. The case for the entire mechanism is made of pine, and varnished with two coats of dark mahogany varnish stain. The clock is wound and the switch is set each afternoon. When I completed this clock, I showed NON~ — PIVOT Construction of the case and electrical mech- anism and appearance of the finished clock other storekeepers how it worked and secured six orders very easily, and feel sure | of more. The expense for material is about one third of my selling price. I make the clocks in my spare time. Popular Scrvence Monthly * ae Youthful Winner of Third Prize Builds Unusual Models > winner of the third prize, Mr. Edward Jones, of Frankfort, Mich., is still in his teens. Born in Kemptville, Ont., in 1903, he attended public schools at Milton, Ont., Benzonia, Mich., and Frankfort, Mich. He clerked in stores, washed dishes and tended fires at a hotel in order to earn his way through high school. “It seems natural for me to use tools and experiment with steam and electric- ity,” he writes. ‘Just how or when I became interested, I am unable to tell, but whenever our family moved to an- other town, my first step was to become acquainted with the machinist. In this way I got a chance to help around the machines and sometimes to run them, either to make some little piece of ap- paratus for myself or to turn out a job for the machinist. Thus I made a small steam engine complete in every detail. At night after the sawmill had closed for the day, I would connect my engine to a steampipe and run it to my heart’s content. : “Another model, which I consider my best, is a little boat run by dry cells and controlled by a clockwork mechanism that starts, stops, and reverses it. Another clockwork device alternately flashes seven lights in different locations. ‘“‘My success in selling the window- light time switch has encouraged me to put my leisure hours in the workshop on a moneymaking basis.” The mechanical drawings with which Mr. Jones illustrated his story were among the clearest and neatest received. Complete Your HE regulation sailing outfit for an open paddling canoe can be purchased for about $25, but may easily be made for less than half this amount by any one who can handle a few common tools. From my experience in rigging up an out- fit for my 16-ft. canoe, I know that any one can do it in a few hours. The outfit SCREW YARD EYE PLIT RING 7B00M K K \ CLOTH LAPPED To 5~ HOOK Y/ FORM NARROW BIGHTS scatweve) f nan ING BAMBOO [K A MAST— V4 Y Roon~ | 2S 1OFT. BAMBOO NY J 2 “WR —SAIL LACED To BOOM JAW 3" WITH HEAVY KORE HALYARD=i6 COTTON ROPE How the sail is made and rigged is light, easily detached from the canoe, and does not mar its appearance. It can be taken aboard when the wind gives out and it is necessary to resort to the paddles. The sail is made of lateen form, as that requires a shorter mast than other rigs. For the mast, bamboo should be selected; it ts light and very strong. For the same 82 _is wanted. By Stillman Taylor reason, the yard and boom are made from bamboo fishing-rods. The material required for making the outfit is as follows: 2 pieces cedar, spruce, or pine, 28 in. long, 10 in. wide, ¥% in. thick, for leeboards . 1 — bamboo, 2 in. diameter, 6 ft. 10 in. long, for mas' 2 pieces bamboo (fishing-rod, whole cane), 1 in. at butt, 10 ft. long, for boom and yard 1 piece cedar, white pine, or spruce, 5 % ft. long, 4 in. wide, % in. thick, for leeboard thwart, bilge blocks, and mast step 1 piece cedar, spruce, or pine, 30 in. long, 3 4 in. wide, 5% in. thick, for mast thwart 9 yds. unbleached cotton cloth, 1 yd. wide, for sail 40 ft. 3/16-in. cable-laid cotton rope, for halyards and main sheet 4 brass lanternboard hooks with wingnuts, for clamp- ing mast thwarts and leeboard thwart to gunwales 1 brass half- or single-jaw (2-in. jaw), for holding boom to mast 3 brass screweyes, 1% in. long, with 44-in. eye, for halyard, boom, and yard 2 brass split rings, for fastening screweyes to S hook 1 S hook to couple boom and yard together The mast is 2 in. in diameter and 6 ft. 10 in. long. In the top is fitted tightly a 2-in. wooden plug in which to screw the eye for the halyards. The triangular sail measures 9 ft. 6 in. on the yard and boom and 9 ft. 3 in. on the leech. Sew the cloth strips together over- lapping % in., and stitch each edge. Un- bleached cotton cloth is good enough, and yard-wide goods will cut to good advantage. After sewing the breadths together, make 34-in laps on both sides 6 in. apart and attach each edge, if a narrow, bighted effect Then cut the cloth to the approximate shape, lay the spars over it and mark the outline of the sail with a pencil. Reenforce the corners with a patch Paddling Canoe Equipment with a Sail of cloth sewed on both sides. Along the yard and boom sides of the sail, fold a strip of cloth and stitch it to make a 1-in. hem. Along the leech make a 34-in. hem in the same way and run a \-in. cotton tape through it. This will be handy later on when the sail stretches; by pulling up the tape, the slack may be taker out of the sail, which will prevent flapping. At each corner of the sail and at dis- tances of 6 in. along the yard and boom, NM LANTERN BOARD = a WITH = WING NUT — —=—S SSH « == ~ LEEBCARD SS THWART LEEBOARD THWART BILGE BLOCK MORTISE “= LEE BOARD Details of the leeboards and mast step and thwart work grommet eyelets for attaching the sail to the spars. This is easily done by making a hole in the cloth at the desired point, placing a grommet ring on each side of the hole, and sewing firmly with waxed cotton string. Use an overcasting stitch. (Continued on page 96) Popular Science Monthly age

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July, 1922 81 O get real satisfaction from your radio outfit choose a battery that you don’t have to fuss with. Even if you know nothing about batteries, the Exide name is your guarantee of first quality and dependable, lasting power. Wherever batteries must be re- liable, great industries and govern- ments throughout the world put their faith in Exide. Every time you use the telephone, it is an Exide Battery that sends your voice over the wire. An Exide transmits your message by tele- The Kind of Battery for Radio Service graph. A great majority of the government wireless stations and those of the Radio Corporation are equipped with Exide Batteries. You can get an Exide Battery specially designed for radio at every place where radio equipment is sold and at all Exide Service Stations. Any of our stations will recharge radio batteries. Exide Radio Batteries give uniform filament current for all types of vacuum tubes. They are conser- vatively rated and will give full ampere hour capacity. THE ELECTRIC STORAGE BATTERY COMPANY Philadelphia Oldest and largest manufacturers in the world of storage batteries for every purpose Ext BATTERIES

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The end of a perfect howl— HE squawls of a two year old are as music to the ear beside the howling demonstration put up by a fractious radio set. And how a set can howl unless one offers the soothing influence of the proper amplifying transformer. Most any transformer can amplify sound, but it will also amplify the stray fields which produce howling and distortion. It takes the Acme Amplifying Transformer with its specially constructed iron core and coil to put an end to the howis and yowls. Only when you add the Acme do you get the realistic tone and volume so markedly absent in the ordinary radio receiving set. The Acme Radio Frequency Transformer greatly increases the range of any receiving set, either vacuum tube or crystal detector type. The Acme Audio Frequency Transformer produces not only volume, but reality of tone. It is indispensable to the satisfactory operation of loud speaking devices. The combination of one or more stages of Acme Radio and Audio Frequency Transformers assures the maximum of range, of volume and of reality in tone. The Acme Apparatus Company, pioneer radio engineers and manu- facturers, have perfected not only Radio and Audio Frequency Trans- formers as well as other receiver units and sets, but are recognized as the foremost manufacturers of Transmitting Apparatus for ama- teur purposes. Sold only at the best radio stores. The Acme Appa- ratus Company, Cambridge, Mass., U. S A. New York Sales Office, 1270 Broadway. Type A-2 Acme Amplifying Transformer Price $5 (East of Rocky Mts.) ACME for amplification Popular Science Monthly THE HOME WORKSHOP Listen-In on POPULAR SCIENCE MONTHLY’S Two-Stage Receiving Set HOUSANDS of radio amateurs have made and are now receiving broad- casted programs with POPULAR SCIENCE MONTHLY’S two-stage receiving set, de- scribed in Blueprint No. 6 of the Home Workshop Service Department’s series of blueprints. The set has won unanimous favor because it clearly brings in distant stations, is exceedingly sensitive in tuning, and can be made at comparatively small cost with tools found in the average home workshop. Many men who are not accustomed to working from blueprints or drawings have been successful in making the set, compli- cated as it is, because of the clearness with which the construction has been described. Each item in the bill of materials is num- This $125 set can be made for about $40 by following the blueprint prepared by POPULAR SCIENCE ONTHLY. For description of blueprint and order coupon, see page 41 bered and each part in the assembly and detail drawings is marked to correspond. The printed instructions contain the same identifying figures. These key numbers are shown on the accompanying illustrations of the front and back of the panel, which give clearly the appearance of the complete set. To Turn a Tobacco Box into an Aquarium A SMALL aquarium, which will be found even better By E. Bade bottom of the tank and cover it with 1% in. of clean sand, than some that can be bought, which must have been re- as well as cheaper, can be made from a large empty tobacco tin. With a can-opener cut out the sides and top, leaving only arim 14 in. wide on each side. Then cut pieces of plate- or window-glass to fit. Make a paste by mixing a little red lead with common putty and peatedly washed in a basin until the water was clear. Plant with water plants. It will be found that the tips of some and the roots of other plants should be used. Before filling the tank with water, place a small piece of paper over the sand so that it will not be stirred up. fasten the glass in place. Putty a plate also to the bottom of the tank. Let it stand for at least a week. Cut an old wire screen to fit snugly into the cover of the can and solder it on. Paint the outside any de- sired color. When the aquarium is dry, it can be planted. Place a little top soil on the Hammering down sharp ‘edges The complete aquarium Let the tank stand near a window for about two weeks, or until the plants have made roots and have begun to grow. Then a few small fish can be placed in ‘the aqua- rium. This makes a balanced aqua- rium that does not require a change of water. Putting in the glass Popular Science Monthly Lege Jult _ | er oe THK st © £2 a.) . a «Cl i ess .lhlUwdA CP

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July, 1922 THE HOME WORKSHOP Your ‘‘Best Idea’’ May Win a $15 or $10 Bonus HENEVER you make some- thing particularly useful and original in your home workshop, write a letter describing it to the Home Workshop Editor, POPULAR SCIENCE MONTHLY, and send in a photograph or sketch to explain the construction. Not only does POPULAR SCIENCE MONTHLY pay well for available articles, but it also awards special prizes for the “‘Best Ideas” published in this department each month. These bonuses for August and Sep- tember will consist of a first prize of $15 and a second prize of $10. The awards for July are: FIRST PRIZE, $15: L. B. Gang- awere, Dunbar, Pa. ‘“‘How to Make a Variable Condenser With Sliding Plates” (see page 88). SECOND PRIZE, $10: A. L. Long, Springfield, Ill. ‘Celebrate the Fourth With a Carbide Cannon” (see page 79). Cabinet Makes Bread Mixing Easy HEN bread is baked at home, the work will be simplified if a cabinet is made for mounting the dough mixer. The mixer rests in a circular hole in the top of the cabinet and is clamped solidly on the top shelf. The pans containing the dough are placed on the shelves of the cabinet during the rising process, and the baked bread and baking utensils are stored in it at other times. It saves many steps and makes bread baking a pleasure.—J. L. D. Dusting Radiators with Air 2 A vacuum cleaner is available, it is a simple matter to dust radiators thor- oughly. Hang an old damp sheet or large dustrag back of the radiator, place the blower attachment on the vacuum cleaner, and blow the dust through the radiator on to the damp cloth at the back. The dust will be forced from every depression in the columns in a fraction of the time required for hand dusting.—J. S. K. (evele) DE, PRATT) | Ko) OT Oat 61 O70) Das WO) 0) ER Pocket Nail-Puller No. 634 Price, $1.25 “It’s no job to pull nails with this nail-puller,” says Mr. Punch A tap with the hammer sinks the jaws in the wood close to the nail. “It looks like a mighty handy little tool—this Pocket Nail-Puller does. It’s small enough to go into a pocket or a nail-pouch, and it’s cheap enough so any man can afford to own one. And every carpenter, regular or amateur, can find a lot of work.for it. Then rap the bevel to 6a close the jaws on the nail. “You know there’s two ways of do- ing a job like opening a box. One is to knock the top off, breaking a chisel A and splitting the cover in the process. & ‘*The other way is to use a Goodell- = Pratt Pocket Nail-Puller, and save your tools and your -feelings— and maybe save the box so you can use it again.” And pull it like this. Could anything be sim- pler? This Pocket Nail-Puller is a regular one of the Goodell-Pratt 1500 Good Tools. And Mr. Punch says, “An honest tool is like an honest friend; they both stick it out to the end.” Write for free illustrated pocket edition cata- log describing the Goodell-Pratt 1500 Good Tools. You’ll find much to interest you in it. GOODELL-PRATT COMPANY, Greenfield, Mass., U. S. A. Zoolmith

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Finish that Radio Cabinet to Match Your Furniture Of course you want the cabinet of your radio outfit to match or harmonize with your other furniture. You can quickly and easily accomplish this with Johnson’s Artistic Wood Finishes. Our book tells how. Use Coupon. JOHNSON’S WOOD DYE Johnson’s Wood Dye is very easy to apply—it goes on easily and quickly, without a lap or a streak. It pene- trates deeply, bringing out the beauty of the grain without raising it—dries in 4 hours and does not rub off or smudge. Johnson’s Wood Dye is made in four- teen beautiful shades, all of which may be easily lightened or darkened— full directions on every label. Insist upon Johnson’s Wood Dye— there’s no substitute. FREE-This Book on Home Beautifying This book tells how to finish wood in artistic stained and enameled effects. Gives practical suggestions on making your home artistic, cheery and invit- ing. Tells just what materials to use and how to apply them. Includes color card—gives covering capacities, etc. Use coupon below. WORK ors. woov FLO and FURNITURE S.C. JOHNSON & SON, Dept. PS 7, RACINE, WIS. (Canadian Factory—Brantford) 5 Please send me free and postpaid your Instruction Book on Home Beautifying and Wood Finishing. The best dealer iu paints here is.................. MEP IREEED, 5 ins 5 055 40's po wen 0s w'ece ce ceees ee ot eer [hee os ee ee ee ee es | | Popular Science Monthly THE HOME WORKSHOP This Arbor, with Its Quaint Gate and Two Seats, Will Add Charm to Your Garden OTHING adds more to the attractive- ness of a well-kept garden than an arbor, especially if it has comfortable seats. Such an arbor is the one designed by the Home Workshop Service Department as Blueprint No. 9 in the series of working drawings it is publishing to help readers of POPULAR SCIENCE MONTHLY in their work with tools. This arbor, with its arch- ed top, its quaint gate, and its two roomy seats, is a perpetual invitation for one to linger and rest be- neath the green canopy of vines. Al- though of dis- tinctive de- sign and sub- stantial con- struction, the arbor may be built easily by any one who can read a working drawing and handle a hammer and saw. It is 6 ft. across the front and 3 ft. 8 in. deep; the height of the center posts is 7 ft. 6 in., and the width of the gate is 3 ft. These dimensions can be varied to suit individual locations or the taste of the builder. The adaptability of the arbor to various uses and locations is, in fact, one of its best features. Almost any plain doorway, back or front, will be improved by it. Com- bined with proper planting, it will lend architectural distinction to an otherwise unattractive entrance. : If the gate is not desired, it may be omitted, although it adds materially to the charm of the arbor. If there is not sufficient depth available for the seats, or if the seats are not needed, they also may be omitted, so that the arbor will consist only of an arched latticework over the gate. In this case it will be necessary to use longer posts and dig post holes for their lower ends. As designed, the arbor rests on 4 by 4 in. sleepers, which are set in the ground. No post holes, therefore, are necessary. The arbor is like a small house of latticework and is so rigid that it could even be moved from one place to another. The sleepers have end-lap joints, and the lower ends of the corner posts are cut in such a way that they rest partly on the sleepers and extend down in the inside corner, so that the whole joint is firm and rigid. The slats are simply nailed to the rails, except in the upper end section, where the slats and rails are halved together for the purpose of bracing that portion of the arbor. The reof bows can be made either by bending 1% in. by 2 in. pieces in hot water, or by building up the curve from %-in. stock. In the latter case, each bow con- sists of two layers, as it were, one layer of The arbor can also be used to add architectural distinction to an otherwise plain entrance two pieces and the other of three pieces, all the pieces being segments of the same circle. By cutting these pieces with a keyhole saw and nailing them together so that their joints are staggered, a strong support for the top slats is formed. In the same way, by using three pieces of 7%%-in. stock, the orna- mental bow on top of the gate is made. The gate itself is of the simplest pos- sible construc- tion. The seats are sim- ply two heavy planks sup- ported on cleats and a front rail, and braced by a diagonal sup- port under the center. For best results cypress or some other good wood for outside work, such as redwood or cedar, should be used. The arbor can be painted white or finished in any manner considered most appropriate by the maker. The arbor blueprint contains, besides the assembly drawing and full size details of the top bow and other parts, a com- plete bill of materials, giving the exact size of each piece. It will be sent to any address on receipt of 25 cents. Make Your Own Radio Set LLUSTRATIONS of the two radio re- ceiving sets, listed below, Blueprints Nos. 6 and 7, will be found on pages 82 and 92. Coupon for Ordering Blueprints Home Workshop Service Dept. Popular Science Monthly 225 West 39th St., New York GENTLEMEN: Send me the blueprint, or blueprints, I have checked below, for which I en- close. ...cents in stamps or coin: No. Title Price A. WOWING=-TAD IC «.6:050i5:0 0s 60's 500 25c O 2. Smoking Cabinet......... 25c . 3. Book Trough End Table....25c CO 4. 30-ft. Monoplane Glider....50% O 5. Kitchen Cabinet..........25¢ LJ 6. V.T. Radio Receiving Set..25c O 7. Crystal Detector Set .......25c i= 8. Shaving Cabinet..... ..... 25e LI 9. Arbor with Gate and Seats.:25c C NMA oie concts Sis eee coo aie wie aes me oto ae oe {Please print) Street 5910 © 6 6 6 ©.» 0-0 456 » 06:0 6.0 0 400% 86 ben the mn = Rwy bra o =] ee Ot fou woo Ss st —_ 7D 4 8 4.70

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July, 1922 THE HOME WORKSHOP This Artistic Floor Lamp Has— Shade of Art Glass By George A. Davis ioe this parlor, piano, or reading lamp, a good cabinet wood should be used, such as bone-dry white or red oak, plain or quarter sawed. The lumber may be ob- tained from a planing mill cut with just sufficient allowance for finishing at the bench, or the parts may be ripped from the board. The wood necessary is as follows: 2 pieces 7% by 3 in. by 6 ft., for box column 2 pieces % by 1% in. by 6 ft., for box column 4 pieces 134 by 3% by 10 in., for base 4 pieces 544 by 3% by 20 in. 1 piece % by 4% by 4% in., for cap of canopy 1 piece 14% by 2% by 2% in., for cap of canopy 4 pieces % by 1% by 12 in., for hip ribs 4 pieces 4 by 1% by 20 in., for plain ribs 4 pieces 4 by 1 by 10 in., for plain ribs 4 pieces 4 by 1 by 6 in., for plain ribs 4 pieces 44 by 1 by 3 in., for plain ribs All the joints are plain butts. They should be nicely fitted and glued and bradded in place. The hip ribs are shaped out of the solid, as shown in the detail. In cutting the holes for the glass in the four canopy pieces, the best way is to use a DOME 920"x 20” . gs 4" a es | RIBSZ * lq we AA ES CATHEDRAL GLASS OO i Beater + SUGGESTION Sag FOR CARVING PANELING MAY BE VARIED IN DESIGN Eq COLUMN SECTION 3 WITH WIRING SPACE COLUMN 3%3°x0@' IT MAY, TAPER TO 24 AT TOP BASE CONSTRUCTION |# = da) se——} eed ole oa ea | a0 = aa An attractive and colorful lamp for the living-room hollow-chisel power mortiser; in this way all four pieces can be prepared at one oper- ation, since they can all be fastened to- gether with the layout on the upper piece only. Cut these holes before making the saw kerf for the glass, which may be done with a \%- or 8/16-in. dado head. If a machine is not available, this space for the glass may be formed by using splines at top and bottom and gluing the whole to- gether. All the work, in fact, may be done with ordinary hand tools. Ease off all sharp corners with sandpaper. A common double-cut file will prove useful in smoothing up the inside edges of the glass frames. The glazing should be done with cathe- dral glass, which may be purchased from any dealer in art glass. The shade looks well if the upper part is brown, amber, and red colored glass and the border green. Pasteboard templates are cut to fit and then used as patterns for cutting the glass. Sheet brass of about 26 gage is sheared into 34-in.-wide strips and formed in a tin- ner’s brake to an angle for the bottom sup- port of the glass in the pyramidal part of the canopy. Make small clips of the same material to hold the glass at the muntins. The column may be left plain or orna- (Continued on page 86) “THE WOOD THAT ALL ITS USERS PRIZE, THE WISE INVESTOR SAFELY BUYS.” When the Baby is a Grown-up and inherits the beautiful garden, the Cypress arbors and trellises and garden seats will be just about as perfect as they are today. She may, tho, have a few nails tightened up, and probably will want to add some new-style ideas in design—and, of course, the new things will be built of Cypress, “the Wood Eternal”. Very likely she will also have the house remodeled or enlarged—with Cypress, ‘‘the Wood Eternal”. But if it is of Cypress now, she will have practically no repairing to do then,—any more than you will between now and then. That’s economy that really counts. Ask the lumberman to show you the Cypress trade- mark arrow (shown below) on every board or bundle. Vol. 28 is the Trellis & Arbor Book. 68 pages. 28 pictures. 23 working plans with specifications. 2 valuable Vine Charts. FREE on request. Write. (Also ask for Vol. 43, a surprise book.) SOUTHERN CYPRESS MANUFACTURERS’ ASSOCIATION »Y¥o> 1249 Poydras Building, New Orleans, Louisiana, z or 1249 Graham Building, Jacksonville, Florida Sle

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Popular Science Monthly

free either in one of our schools near you, or by our home study course— it’s your opportunity to get in the vulcanizing busi- | ness and clean up! Prices of the Famous West- ern Equipment are now even lower than cheap ‘First Seller’ equipment, for an outfit

molds 313 N. Crawford Ave. Here’s your chance to own a real TIRE REPAIR PLANT AT LOW COST With prices on Western Adjustable and Non-Skid Molds now reduced to a minimum — with the mileage guarantee abolished by manufacturers and a contemplated increase in the price of tires—with us giving you complete instructions

repairing all passenger tires, yet the same higher quality of material, workmanship and design, is maintained. They are the same adjustable the same Non-Skid Retreaders with prices in reach of the man with more ambition than money. Write us at once for particulars and tell us all about your own desires, ambition and conditions in first letter. WESTERN RUBBER MOLD COMPANY CHICAGO

Charges Both A and B Radio Batteries Don’t be without the use of your Radio Receiving Set while your battery is being charged. Get a Valley Charger and charge your battery right at home. Attach the Charger to your home lamp socket— attach the clips to the battery terminals and you will get a quick, tapering charge which just exactiy charges your battery, but cannot over- change or harm it in any way. Will charge the A 6 volt battery at a 6 ampere rate, and the B 224 volt battery at the required ampere rate. 45 volt B batteries may be con- ected in parallel go that they can also be c’ ed. SATISFACTION GUARANTEED. If your local stributor cannot supply you, write direct to VALLEY ELECTRIC COMPANY, Department P ST. LOUIS, MO. 22222 @ Mail the Coupon «© <-<<+-<-<« Valley Electric Co., Dept, P St. Louis, Mo. Gentlemen: I am enclosing money order (or check) for $18.00, for which send me a Valley Battery r with five-panel glass display case and indicator. If not satis- factory, I will return it and get my money.

Name

Address $18.00 F.0.B. St. Louis

Ws Wanted — State Distributors County and Town A gents for BAY STATE Wrench Sets. No. 21-1 Set (illustrated) takes place of 128 different wrenches! —sells for $7.00 list. Compact, complete outfit for me- chanics, garage and repair-men, service stations and car owners. Guaranteed against breakage; replacements free; responsible back- ing. Set includes one Combination Reversible Ratchet and Solid Wrench, one Extension Bar, one Removable Adapter for use when wrench is applied direct to socket—either solid or ratchet; a Universal Joint and 8 Allen-process (cold-drawn) sockets of the following sizes: 7/16"; 1/2”; 9/16"; 19/32”; 5/8”; 11/16"; 3/4”; 25/32”. (Sockets chamfered for close work and guaranteed against breakage.) Demonstration will sell this set to any mechanic with money to buy. Territory as- signed to you restricted to yourself. While still openings for State Distributors and -Dis- trict Agents, write for proposition. The Allen Mfg. Co., Hartford, Conn.

| COPPER-ENDS FOLDED-7

| The name is read by pressing open the THE HOME WORKSHOP 1

An Artistic Floor Lamp (Continued from page 85) mented with simple strapwork carving planned so as to hide the joints through most of the length. To set off the spots enclosed by the carving at the top and bottom, they may be tinted with color before the lamp is varnished. Chip carv- ing may also be used to relieve the severity of the pedestal. Fill the woodwork with a good paste filler and stain; then shellac and give two coats of good var- nish. Rub to a dull finish with pumicestone and linseed oil, or ap- ply wax, and rub to a finish. For the wiring it will be neces- sary to obtain two right-angled sockets with candelabra pull chains, two 1-in. nipples to fit thread in sockets and two wall flanges to suit, all finished in burnished brass; 8 ft. duplex flexible lamp cord; 1 stage plug for connection between lamp and base recep- tacle; 2 frosted 25-watt lamps. If it is desired to use the lamp as a hall tree also, two brass coat-hooks may be attached to the pedestal. The canopy may be used without the pedestal as a dome lamp, by suspending it with chains from the ceiling. The neces- sary chains and hooks can be obtained at any well supplied electrical store. f~

. NY ( BRASS ANGLES \ PO \) CATHEDRAL GLASS Details of canopy construction

Old Films Will Make Durable Markers for Shrubs and Trees @ PLACE of wooden tags, try using old photographic films as permanent mark- ers for young fruit trees, small shrubs and plants. They make neater and more per- manent markers. With black ink write the name of the tree or shrub in the middle of the emulsion side of a small film ora piece ofa

FIRST FOLD~y large film. Then ee RAL. UL.~sCOmake two foldsin (ey -----4 the film, so that SECOND FOLD the name is cov-

PIECE OF FILM~4 & ered with two thicknesses of film. Foldineach WIRE end about 14 in., press flat,and fold oneend asec- ond time. Make a hole in this end, attach a short length of copper wire, and twist the wire tightly. This will hold the folded film together.

How film is folded folds.—C. C. RICH.

Holder Prevents Inkstains HIS sketch shows a very useful holder for a draftsman’s ink-bottle. It is heavy enough to

Pipe cap holds bottle INK BOTTLE —_ illi S70. 1 make the spilling | Ml) Be a of ink practically jf ‘i a impossible. The holder is a14%in.standard galvanized pipe cap, which is just large enough to receive the regulation small

drawing-ink bottle —ALEXANDER GRABAU.

awMeo -~F§ Oss 2O

ee ||

Page 73

July, 1922

THE HOME WORKSHOP

ee How to Make a Rotary Lawn Sprinkler of Pipe Fittings By Vernon Orr HE rotary lawn sprinkler that is described below is made entirely of

pipe fittings that can be obtained at any hardware store. The cost is approxi- mately one half that of a sprinkler of the same size bought at the same store. To make the sprinkler, the following fittings are necessary: 3 nipples, 14 by 6 in. 1 nipple, 4% by 1 in. 2 caps, 1% in. 1 tee, 14 in. 1 tee, 14 in. with %-in. side opening 1 piece of %-in. pipe, 14 in. long; threaded 1 union, % in. 1 reducing bushing, from % to 4 in. 1 tee, 44 in. 1 nipple, 4% by % in. pieces of 14-in. pipe, 18 in. long, threaded 2 4-in. caps 1 A hose connection, 1% in. All these fittings and pipes should be galvanized. Into each end of the 14-in. tee screw a 6-in. nipple. On the ends of these nipples put a pipe cap, thus forming a closed pipe about 1 ft. long, with a tee in the center. Into the side opening of this tee screw the 1-in. nipple, then on that nipple put the tee

with the %%-in. side opening. The side A - y~ % HOLE 4 Tt) aia ee J A Rep REDUCER, /f 4 NIPPLE ; / 2 2S a S PLAN 3 TEL i, Sy <a © HOSE CONNECTION The sprinkler is simple in construction opening in this last tee should be perpen- dicular to the closed pipe. The other 6-in. nipple should have the connection for the hose soldered into one end. Screw the other end into the remaining 14-in. opening in the tee. This completes the T-shaped stand for the sprinkler. The 14-in. piece of 34-in. pipe is used for the upright and the threaded half of the 3¢-in. union is fastened to its upper end. The union is then assembled, the nut being - screwed just tightly enough to permit the unthreaded portion of the union to revolve freely without end play. Into the upper portion of the union, screw the reduc- ing bushing, and into that, the 14 by % in. nipple. The 14-in. tee is then screwed on. Take the two pieces of 14-in. pipe and bend each to a 45-degree angle about 6 in. from one end. Screw the long end of each pipe into the 14-in. tee, so that the bends point in opposite directions at about a 22 %- degree angle with the horizon. Close the ends of these pipes with the 14-in. caps and drill a hole with a No. 30 or %-in. drill in the center of each cap. With a hacksaw cut a slot in the plane of the 45-degree bends from the hole back along the side about 3g in. This completes the sprinkler. With 60 lbs. pressure this sprinkler will throw a spray in a 40-ft. circle. Larger or smaller sprinklers can be made by varying the sizes of the pipe and fittings, keeping always to the same general proportions. Before using the sprinkler each time, itis a good thing to oil the union.

Delightful Test To bring you This offers you a ten-day test which will be a_ revelation to you. It will show you the way to whiter, cleaner, safer teeth. Millions of people of some forty races now employ this method. Lead- ing dentists everywhere advise it. You should learn how much it means to you and yours. - Clouded by a film Your teeth are clouded more or less by film. The fresh film is viscous— you can feel it with your tongue. It clings to teeth, enters crevices and stays. Old methods of brushing leave much of that film intact. The film absorbs stains, so the teeth look discolored. Film is the basis of tartar. How it ruins teeth That film holds food substance which ferments and forms acids. It holds the acids in contact with the teeth to cause decay. Millions of germs breed in it. They, with tartar, are the chief cause of pyor- thea. So most tooth troubles are now Pepsadent REG.U.S. The New-Day Dentifrice Ehdorsed by modern authorities and now advised by leading dentists nearly all the world over. All druggists supply the large tubes. prettier teeth traced to that film, and they are almost universal. Now we combat it Dental science, after long research, has found two film combatants. Many careful tests have proved their effi- ciency. Leading dentists everywhere urge their daily use. A new-day tooth paste has been created, called Pepsodent. It complies with modern requirements. And these two great film combatants are em- bodied in it. Two other effects Pepsodent brings two other effects which authority now deems essential. It multiplies the starch digestant in the saliva. It multiplies the alkalinity of the saliva. That is Nature’s neutralizer for acids which cause decay. Send the coupon for a 10-Day Tube and watch these effects for a while. Note how clean the teeth feel after using. Mark the absence of the viscous film. See how teeth whiten as the film- coats disappear. Then judge the benefits by what you see and feel. You will be amazed. 87

10-Day Tube Free ™

THE PEPSODENT COMPANY, Dept. 27, 1104S. Wabash Ave., Chicago, Ill. Mail 10-Day Tube of Pepsodent to COSHH HEHEHE EHH EEE EEE HEH HH HEHEHE COC eee eee eee eee eee eee EEE HEHEHE Ee Only one tube to a family

Page 74

You owe it to your home, your loved ones, yourself! A beautiful little blue steel auto- matic 4% in. long by 3% in. deep. Holds seven .25 cal. bullets—any standard auto- matic ammuni- ion. An ideal gun for a woman. Heavy .32 cal. mil- itary model 6% in. long by 434 inches deep. Shoots ten shots—any standard automatic ammunition. Both models are exceptionally fine guns that usually retail from $15 and $25 up. The very finest quality forged steel and expert workmanship throughout. Ab- solutely guaranteed! If you are not en- tirely satisfied, return within ten days and we will return your money at once. If any defects occur within one year we will repair or replace free of charge. Send No Money! unless you wish. Write clearly your name, address and model you wish and we will ship by return mail. You pay the postman this special price when he brings your automatic. Denver Importing Company Dept. A P. O. Box 276 Denver, Colo. BOOKS ON FLYING Building and Flying an Aeroplane— A practical handbook covering the design, construction and operation of aeroplanes and gliders. Cloth 150 pages. 450 illustrations. Price, $1.00 postpaid. 23 for 25 caliber 7 Shot Automatic~ ? 10-50 for 32 caliber 10 Shot Automatic Including Extra Magazine ~ } $s Harper’s Aircraft Book—Why aeroplanes fly, how to make models, and all about aircraft little and big. It explains in a simple, lucid manner the principles and mechanism involved in human flight, and tells how to design and construct model aeroplanes, gliders, and man- carrying machines. 245 pages. Illustrated. Price $1.10 Postpaid. POPULAR SCIENCE MONTHLY 225 West 39th Street, New York, N. Y. THE HOME WORKSHOP Construct a Variable Condenser with Sliding Plates By L. B. Gangawere A VARIABLE condenser with sliding plates may be constructed much more easily than the rotary type. One built by the writer has 5 fixed and 4 sliding plates, the fixed plates being 314 by 3 in. and the sliding plates 334 by 2 31/32 in. It has a capacity of about .00075 mfd. More plates or plates of larger size can be used, if de- sired. The top and bottom runways are made of 1% by 1 in. maple, 41% in. long. After these are planed up in one piece about 1 ft. long, the grooves are laid out in pencil, full length, 1/16 in. from center to center. A straight edge is clamped along the first line and a broken hacksaw blade worked back and forth until the groove is 1/16 in. deep. The other eight grooves are cut in REAR VIEW, SHOWING CONNECTING STRIP Hl i HA\\ ie y y Ch — / 77° \®) OLLECTING mae 24 a ROD . i SS a a Speusnes Front, top, and end views of the condenser like manner. The four verticals are of maple 4 by \% by 43% in. long. Popular Science Monthly Squelching Old Man Lightning! IGHTNING strikes—then for a mile around high induced charges are created in all conducting mediums like the antenna of your radio set. If allowed to go through the delicate instrument they will ruin it. Squelch the old man’s pranks. Place a Radisco Lightning Arrester on your antenna. Induced charges will go peacefully to earth. The Radisco is weatherproof, It does not affect the strength of incoming radio signals, $3 at your dealer’s, or send to the RADIO DISTRIBUTING Co., Newark, N, J. Ask also for catalogue of Radio Supplies. RADISCO LIGHTNING ARRESTER The runways are sawed to length and the | grooves given a coat of shellac. This should be well brushed in and then scraped out with the back of the hacksaw blade. | The piece left over is kept for a “‘pull’’ for the sliding plates. Aluminum Makes Best Condenser The condenser may be of brass or sheet zinc, but aluminum, if obtainable,,is better as it will not tarnish. The writer cut his plates on a photo-print trimmer. The fixed plates are clamped in a vise and a saw cut about \ in. deep made in one end 34 in. from the edge. This cut is for the connecting strip shown in the detail of the rearend. The verticals are screwed to the bottom runway, the front ones being set back 1 in. from the front so as to be even with the front edge of the fixed plates. The fixed plates are placed in the first, third, fifth, seventh, and ninth grooves, the top runway placed in position, and the verticals squared up and fastened. The remaining section of the runway stick is cut to a length of 1% in., and the second, fourth, sixth, and eighth grooves are cut to a depth of 14 in. The loose plates are now slid into their grooves to see that they work freely, and while they are partly in, the pull block is shellacked and placed over them. With asmail drill make 4 holes through the block and plates and drive in copper wires. These wires make electrical connection between the sliding plates. The block is fitted with a knob, and drilled for the collecting rod, which is a piece of rather heavy brass or copper wire, (Continued on page 89) ‘ Automobile? Books _ The Model T Ford Car Its Construction, Operation and Repair, Including the Fordson Farm Tractor, F. A. Lighting and Starting System, Ford Motor Truck. Vicror W. Pace. 410 pp., 153 illustrations. : Price, $2.00 The Modern Motor Truck Its Design, Construction, Operation and Repair. By Victor W. PaGeE. Treats on all types of motor trucks and industrial tractors and trailers and considers all types of trucks, gasoline and electric, and all varieties of truck bodies. 800 pages, 750 illustrations. Price, $5.00 e e,@e e Automobile Ignition, Starting and Lighting, with Questions anc Answers. By CuHarLes B. Haywarp, M.S.A.E. A comprehensive analysis of the complete electrical equipment of the modern automo- bile. 1,024 pp., 740 wiring diagrams and ills. (including 128 blueprint diagrams-). Price, $3.75 Storage Batteries Simplified Tells how to charge, care for and rebuild storage batteries. Also outlines their in- dustrial uses, including how they are used in central station standby service, for starting autoniobile motors, and én ignition systems. 208 pp., illustrated. Price, $2.00 How to Run an Automobile By Victor W. Pace. Gives concise in- structions for starting and running all makes of gasoline automobiles and how to care for them. Describes every step for shifting gears, controlling engine, etc. 178 pp., 72 illustrations. Price, $1.50 Popular Science Monthly 225 West 39th Street New York City Popular Science Monthly os > =a ae:

Page 75

July, 1922 THE HOME WORKSHOP How to Make a Variable Condenser (Continued from page 88) bent as shown. A small piece of wire is soldered across the ends of the wires that were driven through the block and to the end of the connecting rod. A brass or copper plate, bent into a bracket and drilled for the collecting rod, is fastened to the front vertical by means of one wood screw and a binding post. Thin brass brushes to bear on the collect- ing rod are soldered to this bracket. A pointer is soldered to the end of the col- lecting rod even with the rear end of the condenser. A strip of aluminum is wedged into the saw cut in the rear end of the fixed plates and brought out under a binding post on the rear vertical. A strip of wood about ly by 14 in. is mounted on the verticals, just above the collecting rod and the po- sition of the pointer marked on it when the plates are all the way in. The plates are then drawn out so as to clear the fixed plates, and the position of the pointer is again marked. A paper scale, correspond- ing in length to the distance between these two points, is divided into fifty equal parts and glued to the strip. Keeping the Tire Gage Handy T= tire gage is considered a necessity around every garage and repair shop, yet it is a small article, easily lost, and, alas, also easily sto- len. In fact, after a man is through with it, he is apt to put it into his pocket absent mindedly. This difficul- ty is neatly solved by sol- dering the gage into a small tin can. The can does not interfere with the use of the gage, but it is too bulky to fit easily into the average pocket.—H. F. B. Gage soldered in can ‘‘Raincoat”’ for Auto Distributor OTORISTS who are troubled with rain or moisture getting to the distributor and causing the engine to miss will appreciate this solution of the problem. The distributor is enclosed in a section of inner tube that is gathered at the top to form a sort of bag with open bottom. The tube acts as a raincoat and does not initiate with the inspection or the adjustment of the mechanism.—B. J. Made from inner tube FILEs should not be thrown loosely into a drawer or chest with hammers, wrenches, and other heavy metal tools. It does not take much misuse of a new file to dull it so that it cannot be used to the best advantage.—D. E. J. 89 - Only one-fifth of the buildings owned by the Bell System are shown in this picture. A Telephone City Above is an imaginary city, made by grouping together one- fifth of the buildings owned by the Bell System, and used in telephone service. Picture to yourself a city five times as great and you will have an idea of the amount of real estate owned by the Bell System throughout the country. If all these buildings were grouped together, they would make a business community with 400 more buildings than the total number of office buildings in New York City, as classified by the Department of Taxes and Assessments. Next to its investment in modern telephone equipment, the toward Better Service largest investment of the Bell System is in its 1,600 modern buildings, with a value of $144,- 000,000. Ranging in size from twenty-seven stories down to one-story, they are used princi- pally as executive offices, cen- tral offices, storehouses and garages. The modern construc- tion of most of the buildings is indicated by the fact that the investment in buildings’ is now over three times what it was ten years ago. Every building owned by the Bell System must be so con- structed and so situated as to serve with efficiency the tele- phone public in each locality, and to be a sound investment for future requirements. “BELL SYSTEM” AMERICAN TELEPHONE AND TELEGRAPH COMPANY AND ASSOCIATED ‘COMPANIES One Policy, One System, Universal Service, and all directed EXPERIMENTAL WIRELESS STATIONS By P. E. EDELMAN. The theory design, construction and operation is fully treated, including Wireless Telephony, Vacuum Tube, and wane spark systems. 24 chapters, 167 illus. Price, $3.00 POPULAR SCIENCE MONTHLY, 225 West 39th St., New York Bivtpotouw Only keys of their kind in res age BR | ra ed.) Open and test thousands of different among detectives, policemen, contractors, locksmiths, firemen, mechanics, travellers, home and hotel owners, etc. Give fenton 9 of i security gad ro worth many times their cost. Novel locks. Tell you instantly if your door or l today. Master Key Co,, 125 Manhattan piece Wineinewhe padlocks are burglar proof. Serve in emer- gencies, too. Thousands of sets in daily use St Compass, a Pocket Mirror, and a ing eye, ear, nose pass — It is worth all we cost to locate ne cinder ‘olds pock- oi, Something great—you te po one. Don’t miss it,’ ‘Sent by —" LET Rae eed .¥ SOc Sense eka ** THERE'S MONEY INIT jie-LEARN TELEGRAPH Y5>ine Hore = MORSE AND WIRELES u¢ —T Se ee ee em, OP cum creme 6 op gt ge ee ee . me aes TE ACH YOURSELF on halt eoual tae es cities cost. with the wonderful Automatic : tinental messages, at any speed, just as an expert operator would. Adopted by U. S. Govern- : 3? ment, and leading Universities, Colleges and Telegraph Schools. 3 styles. Catalog free. OMNIGRAPH MFG. CO. a — sa H. Sends unlimited Morse or Con- 18 Hudson Street, NEW YORK

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make it? Isa cage aerial as good as an inverted “LL”? Whatare the latest de- velopments in loop aerials? How can I build a good amplifier? What equipment will I need to receive longer wave lengths? How can I hook up my apparatus differently to get 50% better results? These, and thousands of other important questions are analyzed in Lefer: RADIO HANDBOOK Lefax Radio Handbook is the first real authority on all radio subjects. Lefax knows all—tells how—in every phase of radio. Its authors are Dr. J. H. Del- linger, Chief of the United States Bureau of Standards Radio Labo- ratory and L. E. Whittemore, Alter- nate Chief. It has been officially examined and approved by the Bureau of Standards to insure absolute accuracy. Lefax is technically correct, yet written in everyday language. It insures success in radio for the novice and provides a reliable source of data for the experimenter. It contains not opinions, not hear- say, but tried and tested facts— and always the newest. Knows all—Tells how Lefax (Leaf facts) is loose leaf. By using the Lefax service, you can add new pages every month and keep your handbook per- petually up to date. The price of Lefax is $3.50 in a hand- some six ring binder. It is the cream of radio research in pocket size. Ask your radio or e:ectrical dealer for your copy. If he has not yet secured a supply, order it through him or mail us $3.5 M4 your copy, postpaid. LEFAX, Inc. Room SA, 9th & Sansom Sts., Philadelphia, Pa. Publishers of loose leaf handbooks on scores of scienttfic and technical subjects which are used as authorities by engi- neers, scientists, universities and technical schools throughout the country. Popular Science Monthly THE HOME WORKSHOP This Loudspeaker Is Built Entirely of Wood By Walter Lyon ADIO enthusiasts who are woodworkers can make a loudspeaker that will give good results with a radio receiving set and two stages of audio amplification. The outside of t he loudspeaker may be made of any wood that will match your own wireless cabinet; for best results the interior should be either of white pine or mahogany. The back of the grooved sound chamber, marked 1 in the illustra- tion, is built up of 1%4-in. pieces The soundbox with phones attached glued together. After the ends have been trimmed square, the 6%-in. radius is laid out and cut on a bandsaw or worked out by hand. The curve is then carefully sand- papered to make as perfect a surface as possible. The next step is to lay out guide lines on top of this block and down the back, so that the angles at which it must be cut intersect ee, os Ree ee SECTION FRONT VIEW How the tone chamber is constructed properly with the side pieces. These pieces, which are marked 5, are then at- tached. Part 2 is a 11%-in. block, shaped as shown, and cut with the same angles as part 1. It is then glued and nailed be- tween parts 5 and their bottoms. Part 3 is made of two pieces of 1}4-in. stuff, one right- and one left-hand, in which a channel is gouged, asshown. The pieces ° P wae A | ae oo. . PLAN VIEW wer fh og OD ie @ Hd“ 4\ @! 4 Ne aM Qs roi ti Th - t Sey Jt ivy ' aes hw ;o, & Bei. a oe wreak: | o oon, 4 a] - 1 pad , | We ls a wd METHOD OF CHECKING ny # ' ' ' ‘ \4 v - /1\ |! i vt CHANNELS + SAME ANGLE FOR 1! AND 2 The top view of the soundbox and a sugges- tion for the grooves are then glued together and to the upper section, formed by 1, 2, and 5. In the same way as part 3, part 7 is made in two halves. Parts 8, which are flanged to hold the telephone receivers, may be made either in the lathe or by hand. Glue a thin piece of felt at the bottom of each (Continued on page 91) o-, —_ “a ia on op ee Ly Make ita Real Vacation! VER the hills to vacation land— with care left far behind! Fifty miles or five hundred, good roads or bad, just say where you want to go and a Harley-Davidson will take you there —comfortably, swiftly, economically. Miles are but pleasant minutes— distant lakes, streams and camping grounds are but a jaunt away when you ride a Harley-Davidson. With your pal and a week's provisionsin the roomy side-car, you’re off for the time of your life— a vacation you'll never forget! And you don’t spend most of your vacation money for car fare when you ridea Harley- Davidson. Fifty miles fora dollar—gas, oil, tires and all. That’s all it costs! Ask your dealer for free demon- stration and his easy payment plan. Or write us for illustrated literature. £ Ans , es” & io ( 7 ¢ 4 ‘ L# Harley-Davidson Motor Co. Milwaukee, Wisconsin Altractive dealer proposition for unassigned territories. Address Desk A-2 Harley-Davidson “Worlds Champion Motorcycle. AND THE DEAF HEAR!! THE VACTUPHONE INVENTION OF EARL C. HANSON Through the amplification of tone waves by this wonderful device, we can listen to sounds which no human ears, even those normal and healthy, have heard since the world began. In the same manner, we whose sense of hearing has been sub- normal can now, without effort, hear sounds here- tofore detected only by the perfect ear. The Vactuphone is the first and only hearing instrument using the Vacuum tube, the amplifying device that made the wireless telephone possible. Millions of dollars have been spent in its de- velopment. The Vacuum tube was used to am- plify President Harding’s voice at his inauguration and on Armistice Day. “At last the ideal hearing aid’’ say hundreds of satisfied users. Call for demonstration or write for descriptive matter. GLOBE PHONE MFG. COMPANY General Offices and Factory: READING, MASS. BRANCH SALES OFFICES: Boston New York San Francisco Philadelphia Chicago Los Angel Washingt Cleveland cou inne bott tion the 1 the | part squé perf true LE ——=so tOrAY th Popular Science Monthly ? { ororyYr: wrriaaere ~wz9vrime of

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July, 1922 THE HOME WORKSHOP Homemade Loudspeaker of Wood (Continued from page 90) counterbore, or fasten a piece of automobile inner tube there with a coat of shellac. Parts 4 are blocks to hold the side and bottom away from parts 3, the lower sec- tion of the soundbox, and small strips at the top serve a similar purpose in holding BORER HOLES FOR NOBx3 ROUND HEAD WOOD SCREWS s¢ —| d | SGLUE . BRADDED (9) : : Ps we 2 Horns for holding the telephone receivers D AND the upper part of the soundbox away from parts 6, the sides and back. In shaping the tone channels, a try square, or even a piece of cardboard cut perfectly square, may be used to test the trueness of the curve. Bottle Serves as Cheap but Efficient Aerial Insulator By John H. Schalek HE radio antenna insulator shown in the illustrations has been in use for the past two months. It effectively in- sulates and sup- ports a two wire No. 14 gage flat aerial that is more than 120 ft. long. It has withstood several very se- vere wind and rain storms dur- ing that time without break- ing or losing its insulating prop- erties. The photo- graph shows the insulator holding a miscellaneous lot of iron weigh- ing over 11 pounds. This is equivalent in weight to a four- wire aerial 225 ft. long of No. 14 copper wire. The insulator will proba- bly hold as much as 20 lbs. The sketch clearly shows the construction of the stopper. As the nuts are tightened, Testing insulator with weights (RON WASHER RUBBER TUBING SQUARE NUTS silyl / TAPERED WOODEN (ANTENNA WIRE PLUG !"LONG \sorne In actual service this inexpensive insulator ~—pue a two-wire 120- t. aerial the tapered wooden plug forces the soft rubber tubing tightly against the neck wall of the bottle. is proving its superiority by the reports of its efficiency 91 Lewiston, Me., hears Pittsburgh on a arko Senior. Lubbock, Texas, hears Denver clearly without amplifier, using a Harko Senior. Washington hears De- troit. Pueblo, Colo., hears Avalon, Cal., all on Harko Seniors. Copies of letters confirming these and many other similar reports sent on request. Crosley Harko Senior V Tuner and Detector A simple non-regenerative receiving set, easy to tune and to use. The Crosley hook-up eliminates objectionable radio telephone car- rier waves. Owners are enthusiastic over the results it obtains. The low price is due to the quantity production and its obvious simplic- ity. Does all that expensive sets do and for those who have no technical knowledge and whose interest in radio is only for the enter- uum and control. ste able. contacts. air it is unequaled. Each instrument guaranteed perfect on the money-back basis. Nothing needed but head phones, batteries and tubes to enjoy broadcasted radio concerts. 2-step Ampli- fier to match Harko Senior, in size and fin- ish, area 1 high. Crosley Rheostat for vac- those used Harko Receivers and 2 amplifiers. Sturdy, d Price 60c. Crosley Tap Switches de- signed for constant tension and elimination of faulty nection possible to washer of special Crosley design. Black composition knob, and nickeled parts, each 40c. A Crosley Model B Vari- able Condenser (.0005 mf capacity) Pat. Pending. A radically better condenser, : ) less i 1 resi ¥ tainment that can be brought in out of the pearlon a. ae gets Crosley PorcelainVacuum Tube So panel mountings), biggest sell- er on the market. Price 60c. The Crosley Sheltran is exceptionally efficient. This audio frequency am- plifying transformer has q ratio of 9 pletely shielded. 4x 2k Brice. ‘ice complete We filament current Duplicate of in Crosley Crosley Farts better- cost less - write oe catalog » Gur- Buss wire con- yi —— SS “> My 3 Price $1.75 4 cket (base or 5 to 1. en — ]} | es ® ro} 7 act Send me catalog of your radio apparatus and name of nearest dealer. I give you name of dealer who should i handle them. ] Address Dealer’s name | Crosley Mfg. Co.,Cincinnati,O. Ps; | USE THIS COUPON ARITHMETIC OF ELECTRICITY A’practical treatise on electrical calculations of all kinds reduced to a series of rules, all of the simplest forms, and involving only ordinary arithmetic. 200 pp. Price $1.50. POPULAR SCIENCE MONTHLY 225 W. 39th St. New York by using a Steffey Motor Attach- ment. Simplest machine on the aA? market. Fits any ordinary bi- SS cycle. Easily attached. Prac- tical—Successful. Send stamp for circulars. STEFFEY MFG. CO. Dept. S, 5025 Brown’St., Phila., Pa. Building and Flying an Aeroplane A practical handbook covering the design, construction and operation of aeroplanes and gliders. Cloth, 150 pages. 50 illustrations. Price, $1.60 Postpaid POPULAR SCIENCE MONTHLY 225 W. 39th Street, New York City CONCRETE ON THE FARM AND IN THE SHOP This new book illustrates and describes in plain simple language many of the numerous appliances of concrete within the range of the home worker. Price, postpaid, $1.00 BOOK DEPARTMENT, POPULAR SCIENCE MONTHLY 225 West 39th Street, New York Brand new, absolutely first cord tires. Guaranteed 8,000 miles and adjusted at the list price on that guarantee. he prices below include a brand new United States Tube. 13. 14.10 33x5 Send no money. Just write today and tell us the size of your tires and the number you want. Tires will be shipped C, O. D. with for inspection. unwrapped CHARLES TIRE CORP. $16.10 17.00 8 $22.15 23.20 4 60 $2x44 21.10 05 25.25 3 section All tires have non-skid tread, Dept. 574 2824 Wabash Avenue, Chicago 93

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92 Sectional Receiving Units Build Your Wireless Receiving Set on the ABC Sectional System E here showthree ABC Units which form the ideal combination for a re- ceiving set. They may be pur- chased one at a time if de- sired, enabling you to add to your station at any time with- out discarding any equipment. No. 5010 Crys- tal Detector This first unit is capable of re- ceiving wireless telephone up to 25 miles. The only accessories needed are the “completion pack- age” and 2,000 Ohm head set, making the total price,....$40.00 No. 5013 Com- bination De- tector and Amplifier The first two units make a vacuum tube outfit capable of re- ceiving wireless telephone up to 150 miles. Price, $37.50: and for both units complete, except stor- age battery, -- $94.70 No. 5014 Two- Step Ampli- er The third unit wiil increase the range and signal strength of the two previous units very considerably. Price for this unit alone, $45.00: or for the three units complete, except stor- age battery,.... $155.55 We have avery complete interesting and educational catalogue which you should have. Ask your dealer or write us. Jewett Manufacturing Corp. 342 Madison Avenue, Dept. C7, New York A BC Standardized Radio 94 THE HOME WORKSHOP ' J Popular Science Monthly ————aa Pictures Show Steps in Making Sensitive Crystal Detector Receiving Set D=SIGNED by experts for the Home Workshop Service Department, this set is one of the best crystal detectors that has been constructed. It has met most exacting tests This Is the Now Famous Radio Set of the Home Workshop Service Department’s Blueprint No. 7 in various stages of construction. They are supplementary to the Home Work- shop Service Department’s Blueprint No. 7, which gives full working drawings, per- SP ec tive even to receiv- ing broadcast- ing on an in- door aerial. Other points of interest about it are: 1. It has few parts and is of simple and practically foolproof con- struction. 2. It can be built with few tools. 3. It costs complete with telephones and aerial, little more than $15. —_ ——— SS = sketches, wir- ing diagrams, complete _ bill of materials, and a full-size templet of the Panel, show- ing the exact location and size of every hole that has to be drilled. Even a per- son who is un- familiar with the use of working draw- ings can un- derstand this blueprint. All he has to do 4. It is su- perior in range and efficiency to the majority of sets costing more than twice as much and is better in many respects than the average $25 crystal set. The pictures that follow show the set these tools. the pliers are not absolu The crystal detector receiving set and the tools used in making all of it except the case. i ; geniously designed that it can be built even without bill g iron can be dispensed with, tely essential, and of a drill or bit brace may be used. made with a hammer and saw he solderin is to buy the items in the of ma- terials, drill the panel ac- cording to the templet, make the condensers, wind the coils, and assemble the parts. The blueprint will be sent to any address upon receipt of 25 cents. The set is so in- any kind The case can be SCIENCE MONTHLY crystal detector radio receiving set is to wind 124 turns of No. 24 single silk-covered wire on a cardboard tube 414 in. in diameter and 334 in. long. No wire is wound for a space of about 3¢ in. at the center where the rotor shaft passes through. The winding is car- T's first step in making the PoPULAR How the rotor and tube are wound. No- tice the paths worn by the contact Points of the sliders. Small U-shaped brass clips, made from Paper fasteners, prevent the turns of wire on the tube from being spread apart by the friction of the sliders ried across this space in any convenient way. The next step is to wind the 4-in. ball rotor with as much wire as it will hold. A ball rotor already turned may be pur- chased, although if a lathe is available, it is a simple matter to turn one. Wind up one half of the rotor and carry the wire through a small hole into the central open- ing. Then wind up on the other side, being sute to wind in the same direction, and carry the end through another hole. Splice and solder the ends on the inside. The panel, which is 534 by 84 in., may be laid out from the blueprint simply by placing it beneath the full size panel layout on the blueprint and making punch marks through to mark the exact center of each hole that must be drilled. Panels of other sizes may, of course, be used, provided they are no smaller, as the set could not be compressed into much smaller space. Three-ply veneer 3/16 in. thick, if obtain- able, will serve as a substitute for a How the-slider unit is assembled. The knob composition panel. When the panel alae ee ae has been drilled, me petater oy — Ly e oD an es r run a 6-in. length arm, which is a piece of : No. 8 brass rod, ones clamped He osen readed through- nuts and ae pre The t t sD hreade tot sose iy acer oi a) e inch, through the The lead am, — dlider tube and ball rotor TE ug = es —_— in such a way that ea the ground there are 2 or 4 sisal nuts on the rod in the large center hole of the ball rotor. These nuts then can be tightened against the upper and lower internal surfaces of the ball rotor in such a way as to hold it securely. It is advisable to make the hole through the ball rotor a tight fit for the (Continued on page 93) ry July, . _ 8/32. wood the r Dete and « Note from Popular Science Monthly

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pm? 1922 — THE HOME WORKSHOP Making Crystal Detector Set (Continued from page 92) 8/32 *rod, so that it will cut a thread in the wood. Then pass the projecting end of the rotor shaft through the central hole in the panel and at- tach the tuner by means of two 34- in. No. 6/32 brass machine screws. These screws do not pass through the tube, but clip it to the panel by means of copper burrs. Split three more burrs in half and use three halves on each side as spacers. Next, — attach the rotor 93 Hear the Wireless Concerts atHome from far and near. The latest news, market and weather reports now broadcasted by radio by our Government. Stations all about you 275 page No. 16 Radio Catalog—just out. ‘Send 25c in coin carefully Pee §=6wrapped for your copy of this wonderful book, the most unusual and complete catalog ever put between the pages of two covers. Not sent otherwise. It is not only a catalog, but a wonderful text book on radio. Enormous cost and tremendous demand prevents further distribution at a less retainer.”’ Ever since the year 1909 Duck’s Radio Catalog has blazed the way with everything worth-while and dependable in radio. This catalog eclipses all previous editions. It is all other catalogs in one. No other is even half as large. The complete catalog of the Radio Corporation, with a wealth of scientific data and diagrams, showing how to build powerful radio telephone transmitters, the Remler, Murdock, and in fact all other catalogs, are in this catalog. “Over fifty pages of the latest hook-ups (wiring diagrams), and invaluable and up-to- date data and information on radio, including important instructions for building antenna.’ CATALOG NO.16 The Wiliam B. Duck Co. Detector base, with rod ° and catwhisker in place. knob and pointer Note where the wire and adjust the ro- from rotor is attached Radio Sets Cost Very Little Complete sets sell for as little as $20—some even less. Today there are thousands bringing to pivot screw tor so that it turns exactly in the cen- into their homes music, concerts and news hundreds of miles away, and with a loud speaker to replace the receivers on the ears, the entire family may clearly and distinctly enjoy the la scape EPRI nT “yp i ' i : ; ! entertainment. DUCK’S NEW TYPE “CQ” RECEIVER An Epoch Making Contribution in Radio Reception Combining the Utmost Selectivity and Simplicity of Operation Our new Type “CQ” receiver with detector and two step amplifier is truly a DeLuxe Receiver. Cabinet of genuine mahogany, handsomely finished in its natural color. Formica panel. All connections from rear. No set offered to the public today combines so many dominating features. On the basis of intrinsic worth we are warranted in asking twice the price. Extreme sim- plicity in operation, sharp and selective tuning, clear and sweet reception of music and speech, the entire elimina- tion of body capacity effects, none of the minutely pains- taking adjustments characteristic of so many receiving sets on the market, permanence of adjustment,—these are among the dominating and much to be desired fea- tures that characterize our ‘‘CQ"’ Receiver.: In tests here Schenectady, N. Y., Atlanta, Ga., and Newark, N. J., from 400 to 700 miles distant came in with sufficient strength to be audible in any part of a room 12 x15feet. Chicago, Pittsburgh and Indianapolis were plainly audible in receivers. Pamphlet describing this receiver mailed for 2c in stamps. This rule necessary to prevent avalanche use- less queries. PESOS PROB IGOR ss 5.56 0'saig eievayalere evden aieratiae $85.00 NoOTE:—The above receiver is complete excepting the usual accessorieg.. These comprise detector and amplifier bulb, $18.00; two ‘‘B’’ batteries, $4.50; storage battery, $20.00; antenna material approx- imately $12.00, a head set'as selected. Western Electric from stock at $15.00. SOCKETS DIALS RHEOSTATS (Attractive Discounts to Dealers) We can accept and fill from stock orders in most any quantity for the following items: No. A 700 Bakelite three-inch knob and dial, 3/16 in. shaft............. 0.0.2 cc ceee eens $1.00 No. A 701 Bakelite three-inch knob and dial, 4 in. shaft............... cece cece eeeece 1.00 No. A 666 Bakelite Moulded Socket, with highly polished metal receptacle mounted into base, ANd Conmneecions frail COP OF DASE. « .06 65 bcc seses scious denssesieceeee 4 No. A 650 Filament Rheostat. One of the very best on the market...............0.. 1.00 The above items will have refinements found on few others of a competitive nature. Our mould capacity on these items is very big. Dealers should address Dept. K. DEALERS We want live responsible dealers in every city and town in the United States, both for the sale of our extensive line of radio apparatus and all other worth while lines of radio goods on all of which we can quote attractive discounts. We can offer you facilities and advantages that no other radio house can offer. THE WILLIAM B. DUCK CO., 224-228 Superior St., Toledo, Ohio ter of the tube. The tuning of the primary is accom- plished by turning two sliders, the ends of which touch the turns of wire in such a | way as to make contact. One of the sliders covers one half the turns, and the other slider, on the other side of the panel, covers the remainder of the turns. For the sliders use knobs that have shafts fastened to them or knobs that have collars and set screws so that a short length of 8/32 rod can be fixed firmly to them. Knobs with 8/32 bushings can be used only if the rods are pinned to them. On the under side of the panel a strip of No. 30 B. & S. gage spring brass, 14 by 21 in., is fastened to each slider rod by being fast- ened securely between two nuts and lock- nuts. Each slider is dented slightly with a center punch near the outside end. It is this projection that makes contact with the turns on the primary tube. Be sure that the two strips cover every turn of the winding. No great amount of tension is necessary when once ‘the insulation has been cut away. The catwhisker is attached to a 2%-in. length of 8/32 rod that passes through a How to Bec S ful Electrici neat cope siees teawtesaa'e | THE, MODEL T FORD CAR The studies to be fol lowed, atone = work, —- rad operation and the requirements of the successful electrician are pointed . > out and fully explained. 202 pages. Illustrated. Including the Fordson Farm Tractor, F. A. Price, $1.50 Lighting and Starting System, Ford Motor POPULAR SCIENCE MONTHLY Truck. Price $2.00 Postpaid. 225 West 39th Street, New York POPULAR SCIENCE MONTHLY, 225 W. 39th S.. New York tor rod, one end of which has an adjusting Ri pagt tpg Pala Y «GUARANTEE other is the crystal cup with a mounted Yy, ay crystal. There is space for another crys- tal cup alongside of the one shown. In Its Construction, Operation and Repair, Top view of panel. At the upper left are the aerial and greg binding posts, near which is one of the slider knobs. Below it is the three-point condenser switch. In the center is the rotor knob. Above, at the right, is the detector unit, which is in two parts. One is a swiveling wooden ase, through which is pivoted the detec- 8.000 MILES Our Guarantee and challenge assures every customer full protection. You can’t afford to . the lower right-hand corner are the tele-. overlook these wonderful pede or yy thew tires at —_ phone binding ponte on and the other slider low prices. Brand new— nob igh “Py guaranteed 8,000 miles and b freed price on that thang THESE PRICES INCLUDE NEW PURE GUM TUBE FREE Soxare° “sos 3ax2."."." “Iaeo suena *Ba20 32x31-2 13:85 32x41-2° 21.45 33x85... 36-30 1x4 -- + 1810 33x42 0622160 38x85 *.”.”, No money in advance. Just RUSH ORDERS! DON'T DELAY No,money in advance. Just Toa = ting the sizes and number of tires you want, All tires shipped ing our tires not C.0.D. Pay after you have examined. be strictly Firsts WILSON TIRE CO., Dept. cs7 325 E. 33d St., CHICAGO slot in the wooden detector base and is pivoted between two wood screws. The construction is shown clearly in the illus- trations. The step condenser is simply three small (Continued on page 94) July, 1922 95

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94 Popular Science Monthly For Household and RADIO Use Bargain No. 1—The effi- cient 4% h. p., 110 volt, 60 cycle, A. C. Motor shown in the cut. Weighs 28 lbs. and easily takes care of &% h. p. peak loads. "hast the motor for washing machines, grinders, large ventilating fans, cream sepa- rators, drills, anen, ant S other tools - 13. 50 Bargain No. 2% A. C. Synchronous “Motor, ~ operating spark gap - Bargain No. 3—)4 for charging “A” Ritecios - = & = = Bargain No. 1. Weight 38 Ibs. bare. Motor and Generator Bargains h. p., 110 volt, 60 cycle, $20.00 h. p. ious and Generator set; 110 volt, adi cycle; Bargain No. 414 h. p., 110 or 220 volt, 60 cycle, A. C., Combined Motor-Gene- rator with low voltage for charging “‘A” Battery, and 500 v olts for broadcasting Bargain No. 5—Big capacity Grinder and Buffer, using the 14 h. p. motor described in Has 6-inch Abrasive Wheel and 7 inch Standard Cotton Buff. Usual price is above $50.00; our cash offer - Immediate Shipment from Stock on receipt of price. price will be refunded on return of goods within thirty days. NORTHWESTERN ELECTRIC CO., 410-420 So. Hoyne Avenue, Chicago Either with Binding Post Terminal like cut or Cord and Plug. $35.00 $100.00: $25.00 All are fully guaranteed and purchase You Can Command big money and a per- manent district man- ager’s position by appointing distribu- tors and selling the famous scientific Tube-Saver that automatically heals punctures, preserves tubes and can be applied instantly with a tire pump. BERRYMAN’S TUBE-SAVER increases tire mileage at least 35¢ and is the ulti- mate answer of science to fF the question of tire econo- my. Some good territory still open for capable district manager. State experience when writing for further information. Address: Tube-Saver Division Berryman Rubber & Tire Corp. 1776 Broadway, New York Radio Hook-Ups In this book are shown all the best circuits for damped and undamped wave receiving sets, buzzer, spark coil and transformer sending equipment, as well as vacuum tube telegraph and telephone transmitters, wavemeters, vacuum tube measuring ——— audibility meters, etc. e, 75 cents POPULAR SCIENCE MONTHLY 225 West 39th Street New York City, N. Y. | BLANK CARTRIDGE PISTOL Protection against Serene, Tramps, & Doga PRICES ; ae on as i Genser tolife. Li Betis B id: i Blank pee ase by express, S ‘JOHNSON SMITH & CO., De ob 3224 N. Halsted St., on CHICAGO Automobile Repairing Made Easy By Victor W. Pace. A thoroughly prac- tical book containing complete directions for making repairs to all parts of the motor car mechanism. 1,056 pp. Price, $4.00 POPULAR SCIENCE MONTHLY 225 West 39th Street New York City Why Good Dancers Are Popular Write at small cost! ARTHUR MURRAY, Studio 266, 100 Fifth Ave., N. Y. 906 Arthur Murray, America’s Greatest Dancing Teacher, In- vents Remarkable Method that Teaches You to be a Good Dancer in a few Hours at Home—at Very Little Cost! Everyone wants to meet and dance with the really good dancer. No longer need you envy those who dance the latest ballroom steps. Murray, the Vanderbilts’ method which enables anyone to become an accomplished dancer quickly. easily—and at very little cost—right in the privacy of your own home. No music or partner is necessary. 60,000 have learned to dance by mail. You can learn the Fox Trot, Conversation Walk, Waltz, One Step and all the newest dances at home in a few hours time better than from a personal teacher, and at a fraction of the cost. Five Dancing Lessons Absolutely Free To show you how easily and quickly you can learn the newest steps by Arthur Murray’s remarkable new easy method, he will solutely free, in plain cover, a fascinating step in the Fox Trot, The Secret of Leading, The Secret Of Following, How To Keep Time To Music and The Correct Dancing Positions. Surprise your friends—be more popular by becoming a good dancer— quickly! Send for your free lessons today! To help cover cost of advertis- ing, mailing, etc., send 25c, a small part of our expense. Should you decide totake lessons from your” ms. . mncloeed is Mr. Murray, the 25c will be allowed on future orders. \ Today! Learn at home— easily — quickly — Arthur instructor, has invented an entirely new send you ab- ee MURRAY, Studio 266, 100 5th Ave., N.Y, poore vos can teach me the new dances quickly, send me 25c to cover mailing in plain mIepDer. lecide te take lessons — Mr. Murray, it is understood that you will credit me with 25c » | PRINT NAME | ADDRESS | CITY AND STATE : ee THE HOME WORKSHOP Making Crystal Detector Set (Continued from page 93) condensers made from tinfoil and waxed paper. One is made of two strips of tin- foil 14 by 2 in., the second of three strips, and the third of five strips. Each strip is insulated from the others by means of waxed paper, and leads from the strips are taken out alternately to the right and left ends by means of fine wire such as may be obtained by untwisting a short length of ordinary lamp cord. When each condenser is finished, it is folded in two places so as to form a square approximately 34 by 34 in. and bound with a piece of tape or Under side of panel, showing tube, water. and wiring. otice at the left one of the slider arms clamped between nuts to the threaded shank of the slider knob. The other slider rod can be seen at the right, gd concealed by the curve of the tube. he small wax paper package at the left contains the step condenser. The under side of two of the three condenser switch points can be seen just back of the con- denser. At the right is another package containing the phone condenser. Notice how the tube is fastened to the panel with a machine screw, nut, a copper burr, and three half-burrs used as spacers. Notice also the method of carrying the ends of the winding on each half of the rotor peat to the inside and splicing them, and the way the flexible leads are taken from the rotor. Below at the right is a part of the detector rod base and cat- whisker and at the left the aerial and ground binding posts gummed paper. Bending them in this way fastens the fine lead’ wires firmly so that there will be little danger of their pulling out. The leads from one side of the three con- densers are taken to the condenser switch points. The leads from the other side are twisted together and taken to the aerial binding post. The condenser switch arm is connected with the ground binding post. It is necessary also to make a fixed con- denser of two pieces of tinfoil 2 in. square. The same general method is followed, even to folding the condenser. One lead is taken to one telephone binding post and the other lead to the other telephone bind- ing post. The’ condensers are so small they may be suspended by means of their leads, especially if these are enclosed in spaghetti tubing. The remainder of the wiring is simplicity itself. One slider is connected with the ground binding post and the other is con- nected with the aerial binding post. One end of the rotor winding is connected with a telephone binding post and the other one with the pivot screws holding the detector rod. The crystal cup is connected with the other telephone bind- ing post. In order to have the connections from the rotor as flexible as possible, it is well to (Continued on page 95) July, 2000 $6. Wh hear equi Used ators ante reful adju extr: 200 uunneneent —_— . Popular Science Monthly 3

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July, 1922 3000 Ohm $7.50 When you “tune in,’’ you will be sure to hear everything distinctly, if your set is equipped with a Peeriess Radio Head Set Used and endorsed by professional radio oper- ators. Made of high quality materials and guar- anteed to give satisfactory results or money refunded. PEERLESS Radio Head Sets are adjustable to fitany head. Ear caps are made extra deep to fit comfortably. Immediate Delivery Send Money Order or Certified Check 2000 Ohm Set $6.00 3000 Ohm Set $7.50 Prepaid United Radio Corporation, Mfgr. Caledonia Ave., Rochester, N. Y. WIRELESS New License Quiz Book FOR APPLICANT TO United States Government’ New Rating of : Radio Operator’s License Examinations This is the first edition printed with the new rules, regulations and gradings laid down by the government. It gives a full description of various hook-ups, new devices, practical equations, inter- national law and regulations, official grad- ings, diagrams, definitions and other im- portant information. No amateur or wireless professional can afford to be without this book. 107 pp. 80 Illus. Price $1.00 POPULAR SCIENCE MONTHLY 225 W. 39th St., New York City Make Your Face Show Manhood Every real man wants the clear, rugged, ruddy face of a real he-man; the healthy, clean skin and alert expression that comes from a vigorous life in the open air. All men want it—all women admire it. You can have it. > A Man’s Cream For a Man’s Face —is a true facial invigorator and tonic prepared for men. Two minutes’ use brings the red blood tingling to the surface, removes that oily, sallow appearance and ‘eaves the skin clean, clear, firm and with healthy color. It invigorates and hardens the facial muscles and promotes an alert, forceful expression. A sixty-day treatment—with money-back guarantee—will be sent to you for a dollar bill. Manhood Commands Admiration Men and women all admire the man whose face shows the clean vigor of perfect health. Stag is made for you men who want to be one of those ruddy, forceful, hard-hitting fellows who are al- ways so popular. Send your name, address and a dollar and it will come to you by return mail ~fully guaranteed. Stag Laboratories 1267 Park Place, West Dept. 711 Detroit, Mich. THE HOME WORKSHOP 7 Making the Crystal Detector Set (Continued from page 94) make two “pigtails” by twisting together four or five thin wires from a length of lamp cord. If the rotor does not remain fixed, but has a tendency to spring back after being adjusted, arrange two opposing springs of twisted wire at the bottom of the case to grip the rotor rod with sufficient tension to overcome the torsion of the rotor leads. The panel may be fitted into any kind of box that suits the fancy of the maker. The one shown in the blueprint is 15 in. long, 634 in. wide, and 6 in. high. A lid may be added if desired, 3 in. being a convenient depth for it. In testing and adjusting the set, it will be noticed immediately that the tuning is very sharp and that a trifling turn of either slider or rotor will tune a station in or out. With certain telephones the fixed telephone condenser does not seem to be necessary, due to the condenser effect produced by the two conductors in the flexible cord leading to the phones. My Ideal Radio Receiving Set (Continued from page 72) unknown guest. And there is no rude awakening, as when the automatic stopper on the phonograph fails and I have to hop to the throttle. Summed up, my ideal radio station, the station of my dreams, is one that will let me hear anything that is going on between the meridian of Washington and 180 de- grees east or west, and between Peary’s pole and the one Scott hung a tag on. Witha loop of wire no larger than the old-fashioned yarn reel, and a box that I could carry under my arm, I have heard France sending messages to America. Not an inch of wire outside the room where I was listening in. No reason why I should not reach out after Bagdad, Irkutsk, and Tokio. I want both the simple but efficient galena detector outfit and the most sensi- tive amplifying receivér, mounted in a case that can be wheeled around as easily as a tea cart and connected in any room in the house with any kind of an aerial that will best serve the purpose of the moment—a high and long one for long-distance work, or a loop that will shut out interference from two directions and give good results on moderate distances. Then I want one of those little receivers packed in a case as light as my wife’s hat- box. With it I want a loop that will lie flat on top of an automobile when not in use and stand up and turn as desired when in use. I want to use it on motor trips and on the train and steamship. I shall need it with me if by any chance I have to spend a season in a hospital or a sanitarium, or a jail! I have stood on the tops of mountains and looked down at farmers plowing in the valleys, factories spouting their black smoke upward, traffic cops steering lines of cars that look like beetles, busy humanity engaged in scores of occupations. I have whizzed through hundreds of miles of European atmosphere in a giant airplane with the dramatic activities of post-war restoration going on within my sight throughout vast areas. But when I want to get the feeling that the world is mine, to unroll before me, I sit in a big armchair in a darkened room with my ideal radio outfit by my side. 95 Get all the joys Vacation Holds in Store for You —On the Way to Camp— If you go by auto a Tyces Auto- Altimeter on. the cowl of your car and a compass in your pocket, will tell you the altitude, predict tomorrow’s weather, give you directions. In Camp In camp, a Tycos House Ther- mometer will give you the tem- perature at all times. A Tycos Aneroid Barometer will indicate weather conditions in advance so you can make definite plans for tomorrow’s activities. A Tycos Bath Thermometer thrown in the lake will tell how cold the water is when you take the morning plunge. A Taylor Oven Thermometer will help in taking uncertainty and drudgery out of baking. A Taylor Candy Thermometer with tested recipes will enable you to make special dishes, desserts and candies. A Tycos Fever Thermometer will be a first aid in real or fancied illness. On Trips from Camp When you leave camp for favor- ite fishing grounds or on hikes through uncharted woods, carry a’ Taylor Compass to know where you go and wear a Tycos Pedom- eter to tell you how far you go. Simply write ‘‘Send me, without obligation, literature that tells how Tycos and Taylor, Vacation Helps Assure all the Joys Vaca- tion Holds for Me.” Taylor Instrument Companies ROCHESTER, N. Y. There’s a %cos and Zr Temperature Instrument for Every Purpose 133

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96 Arkay Radio Products Indispensable to Your Wireless Equipment ARKAY VARIABLE CONDENSERS ArkayVariable Condensers increase the sensitivity of your tuning set; afford a delicate adjustment on low capacities and insure positive operation throughout the range. .Made ,with hard alumi- num plates. Cannot warp. 15 Plate— 0005, Mid. Capacity $5 29 Plate— 001, Mid. Capacity $6 ARKAY VERNIER ADJUSTER You can tune closerand sharper if you will attach this adjuster to Hy your dials. Spring HAs keeps the adjust- er pressure cone stant. Price, $1. ARKAY LOUD — SPEAKER RADIO The Arkay Horn fits any make of receiver, works on one or two stages of amplification, amplifies your sig- nals, speech or broadcasted con- certs without the slightest distor- tion. You get wonderful results through the Arkay. Black enamel $5 Polished nickel $6 A detector with universal adjustment, permitting the whole face of the crystal to be searched for sensitive spots. Cannot be jarred out of adjustment. Takes eithe: mounted or unmounted crystals. Price, $1. DISTRIBUTED BY CANTON, OHIO NEW YORK, N. Y. Wireless Mfg. Co. Ship Owners Radio Ser- DETROIT, MICH. Grier Battery Supply Co INDIANAPOLIS, IND. Hatfield Electric Co. MILWAUKEE, WIS. Kesselman- O'Driscoll Co. NEWARK, N. J. Radio Distributing Co. Wholesale Radio Equip- ment Co. vice, PHILADELPHIA, PA. Philadelphia WirelessSales Corp. . Schimmel Electric Sup~ ply Co. Radio Electric Co. PITTSBURGH, PA; Robbins Electric Co. Ludwig Hommel & Co. NEW YORK, N. Y. Manhattan Electric Sup- | TOLEDO, OHIO ply Co. Marshall-Gerken Co. Manufactured and Distributed by Riley-Klotz Mfg. Co. Inc. 16-18 Mulberry St., Newark, N. J. Dealers Write for Proposition THE HOME WORKSHOP Improve Your Paddling Canoe (Continued from page 80) The mast thwart is made of -in. stock as shown, with a hole in the center for the mast. It is attached to the gunwale of the |canoe at each side by means of L-shaped | hooks held in place by wing or butterfly 'nuts. If special hooks cannot be obtained, | the regulation lanternboard hooks, obtain- | able at any marine hardware store, and used ‘for attaching lanternboards to the rigging of sailing vessels, may be used to good ad- vantage. The foot of the mast is supported Sail diagram, eyelet detail, and mast step overs RING ON, EACH SIDE EYELET FORMED BY OVERCASTING STiTcn — 7 -@ ——_f— > REENFORCING PATCH MAST STEP the mast should be a snug fit. Screw this grating is used, to a rib, taking care that the screws are not long enough to go all the way through. The leeward thwart has bilge blocks screwed to it at an angle to conform to the curve of the canoe. Make a shallow mor- tise in the bilge blocks to let in the ends of the leeboard thwart and fasten them to- gether by screwing through the outside of the blocks into the edges of the thwart. Before doing this, however, insert a 2-in. into the thwart mortise, driving it in tightly justable at any angle. here. water more easily. means of common heavy fishline. round piece of %%-in. brass, 8 in. long. lee side of the canoe at the stern. canoeist sits on the floor of his craft. each lid.—RutTH D. SHULTIS. in a mast step of 5-in. soft wood, in which step to the grating of the canoe or, if no stove bolt in the center of the bilge block and letting the end project through the face of the block. This bolt, fitted with a wing- nut, will carry the leeboards, which are ad- The leeboard thwart is attached to the gunwale of the canoe by means of hooks in the same way as the mast thwart. The length of the leeward thwart depends upon the width, or beam, of the canoe; the average length is given The leeboards are of %-in. stock cut to the dimensions shown. The edges of the boards are planed down to \ in. thick at the sides so that they will slip through the The sail is laced to the yard and boom by The yard and boom are attached by driving a wooden plug in the ends of the bamboo, screwing in medium size screweyes, clipping split rings in the screweyes, and coupling yard and boom together by means of an S hook. The boom is kept close to the mast by means of a half jaw, as shown. Any hardware store dealing in boat supplies will have this, or it can be made from a half- The sail is hoisted by a halyard of 3/16- in. cotton rope running through a screweye in top of mast. One end is tied to the yard asshown. Norudder is used and the steer- ing is done by means of the paddle on the The THOSE who have oileans and other con- tainers’ with small screw tops know how often the tops stick. To give a greater leverage, I soldered a large nail across Popular Science Monthly 7 For Every Use there’s an Atkins Saw. The name “Atkins” on the blade is a guarantee it will cut faster and easier—save you time, labor and money. Remember when you buy a saw for metal or wood cutting—get an Atkins, Get This FREE Book ‘“*SAW SENSE ”’ We'll mail you this useful book without charge—besides describing Atkins Saws for every cutting use, it is full of helpful facts on caring for saws and interesting facts on construction work. Just send your name and address and the use*you make of a saw to— E. C. ATKINS & CO., Inc., Makers of ‘‘Silver Steel’’ Saws & Tools INDIANAPOLIS, IND. EMER TET EE DEES ET Dept. R, CONSTRUCTION OF INDUCTION COILS and Transformers. By T. S. Curtis. Open and closed core transformers are both taken up. Price, 25 cents Popular Science Monthly, 225 W. 39th St., New York 1 Jewel Burlin jepton nos) sa a ear Gold eprese Case ‘D Cnty One Deller Dows will bey thio = fiece o watch manufacture. The balance you are allowed ¢ Rey y in small, grey: monthly payments. A 21-Jewel atch—is sold to you - J a : ore mgch lower than that of other hi itches. aides, you have the selection 0: the finest thin mode ~~ cae ‘or today ond lat latest epee | = watch SUECLAL OF PE: , WhileThis | | - Writes. Get the Barlington ¥ Wetch Book—write today. Find out about this pecial offer whieh is bein made for ou © a nited = You will know a grea’ deal more about ty 4 took when you read this ~ way = teer clear’’ of the over- D w which are 0 better. ite for and our special offer TODAY! Burlington Watch Company

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July, 1922 Want Se Ss THE HOME WORKSHOP Easily Made Merry-Go-Round Provides Fun for Kiddies A FATHER with several children of his own and an interest in his neighbors’ children, constructed this unique merry-go- round on a vaeant lot. The stump of a tree was utilized for the base. A piece of 114-in. pipe was set upright in the stump and held Four children at a time can ride this sturdy whirler plumb by pouring cement around it. The concrete also formed a substantial coating over the stump. The framework of the swing was sup- ported by the pipe. Two pieces of 2-in. plank made seats for four children, who either push themselves around with their feet or get another child to turn them. Once in motion, the swing will revolve for a- considerable time, merely by its own momentum.—F. W. SHULTIS. Shelf under Automobile Cowl A SHELF under the cowl is handy for the automobile shopper or tourist. Small packages may be laid on this shelf without fear of being stepped on or sat upon. When touring, the road map may be kept at your fingers’ tips, and your best SO | ae Provides handy place for packages hat may ride without causing the least ripple of worry as to its safety. The shelf should be cut a little less than the width of the car body so that it may easily be placed in position and removed. The front edge is notched to fit around the steering column, on which it rests; the back edge rests on bolt heads or a cleat.—W.S.R. Bicycle Drives Ice-Cream Freezer ipl AN old bicycle frame is lying useless in attic or cellar, or if one can be purchased cheaply, it will pay to rig it up so that it can be used for operating an ice-cream freezer. The frame is blocked up, bolted rigidly, and braced so that a person can sit on it and pedal; and a chain is used to transmit the power to the ice-cream freezer, on which the crank is replaced by a cog wheel.—GEOoRGE L. DouGLass. 97 A Partner for Your Every Outing OU outdoor folks, who spend your week-ends or entire summers at lake or stream, in camp or cot- tage—for you what vacation pal can compare with an EvinrudeP Distant fishing grounds, favorite picnic spots, neigh- boring resorts and beaches—all are quickly and easily reached when you have one of these husky little motors to relieve you of oar-work. And every member of your family can use the Evinrude—it’s so simple to operate. You now have the choice of two Evinrude models— the Standard, for more rugged service, and the Light- weight, an easily portable 50 pound motor, preferred by many sportsmen. See these Evinrudes at your hardware or sport- ting goods dealer’s. Or write for free catalog a Built-in-Flywheel'Magneto, Tilt- up Attachment and other Evinrude features. EVINRUDE MOTOR CO. Milwaukee, Wis. 697 Evinrude Bldg. Evinrude Outings No. 4 Off for a day at the island. EVINRUD Standard and Lightweight DETACHABLE MOTORS FOR WATERCRAFT DISTRIBUTORS: 69 Cortlandt St., New York, N. Y. 780 Commonwealth Avenue, Boston, Mass. 440 Market St., San Francisco, Cal. 211 Morrison St., Portland, Ore. too, for cuts, scratches, skin abrasions, etc. Excellent fo E AbsorbineJ: THE ANTISE oa ENT LIGHTNING! //1! “JACOBUS” VACUUM Aerial Protector Type J.S.W. Eliminates Switches. Receiving stations equipped with JACOBUS Protectors do not require lightning or ground switches. Protection every minute of the day and — No worry about throwing switches. Good for Innumerable Discharges. Discharges of lightning or static on the JACOBUS do not affect its life. After conducting a discharge to the ground, the tube is ready for anether operation. Does not weaken or in any way affect the efficiency of the set. $2.00 From All Dealers APEX ELECTRICAL SPECIALTY CO 77-A Orange Street, Newark, N. J.

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98 An Easy, Fascinatin Way ie tenons e CHEMISTRY AT HOME ECAUSE of conditions which grew out of the war, there never was a time in the history of America when chemists were in such demand as now. Good salaries await the right men. No work is more interesting—no other profession offers greater opportunities. For 30 years the International Correspondence Schools have been training men in just your circumstances for success in Chemistry and over 300 other subjects. They will help you prepare right at home for a position in the line of chemical work you like best—or in any other work that ap- peals to you. Thousands of men have stepped into fine jobs through I. C. S. training. Let the I. C. S. help you, too. Choose the work you like best in the coupon below, then mark and mail it today. This doesn’t obligate you in the least, and it will bring you the full story of what the I. C. S. can do for you. ——_—oSe ao oe TEAR OUT HERE — — — — —. INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7692-B, Scranton, Penna. Without cost or obligation, please send me complete in- formation about the subject before which I have placed an X: CHEMISTRY High School Subjects Pharmacy Advertising Mechanical Engineering | (] Salesmanship Civil Engineering L] Bookkeeping Architecture (] Civil Service Electrical Engineering _] Railway Mail Service LJ Stationary Engineering _] Traffic Manager Drafting [Business Management LJ Surveying (_] Certified Public Accountant CL] Automobiles (] Airplane Engines ()Stenography L] Wireless a Address Print Your Own cards, circulars, labels, tags, menus book, aper. Press $12. arger Job up. Ee ate INHALF. =o SMALL TLAY. Pays for 1 itself in coe time. Will last 7»for years. Easy to use, printed rulessent. Print for others, BIG PROFIT. Write factory TODAY for press catalog, TYPE, 08. os envelopes, “T hear you. Ican hear now as wellasanybody. ‘How?’ With THE MORLEY PHONE. I'’vea pairin my ears now, but they are invisible. I would not know I had them in, myself, only that I hear all right.” The Morley Phone for the weightl adjust it. “Geer ons banaed ts sand yg ey housand sold, THE MORLEY CO., Dept. 797, 26 South 15th Street, Philadelphia THE HOME WORKSHOP Resilient Bait-Casting Rod Was Made from Buggy Whip By H. C. McKay MAY of the joys of bait casting are missed by the younger fishermen be- cause of the expense of a good outfit. A steel rod has not the necessary resiliency, to my mind, for the finest work, and a good split bamboo rod is expensive. For less than $2.50 I succeeded in making a rod I would not trade for all the fancy ones on the market. It is not a nickel- plate-shiny-silk-and-varnish one, but it is This strong, well-balanced rod cost less than $2.50 to make a real rod for fishermen, and “handles” right. The rod is 40 in. over all and it has double ring guides, brass tip, silk windings, and handle of soft cord. To make a similar one, first obtain a fairly good rattan buggy whip and strip the covering from it. You will find that the core is of two pieces, joined as shown in Fig. 2. The lower end usually is of fairly stiff and tough wood, while the tip is rattan. Cut this core 12 in. below the joint and from 18 to 20 in. above. This will give a rod from 30 to 32 in. long. Sandpaper smooth and lay it aside. Next, procure an old cane fishing-pole and cut out a section, as shown in Fig. 1. Figures A and B are to be finished off for the butt of the rod and C and D mark the end of the socket into which the rod proper is inserted. Purchase a reel seat, two guides, and a tip of whatever style you prefer. The guides and tip should be placed in such a position that the bend of the rod comes in the direction shown by the dotted lines of Fig. 2. Tie the guides on the rod at 10-in. intervals with a loop of silk sewing thread; then, starting at the outer end of the guide base, wind three spiral turns toward the guide itself. Loop the thread around the spool so it will not unwind. With the spool swinging, stand up and twirl the rod slowly through the fingers, guiding the thread with one forefinger so that it will be wrapped on B FIG.1 D Ee 1G rt + (in alan an iia i Sa IF FIG 2 iy iia For the rod butt, a piece of cane is cut as at A-B and C-D, Fig. 1. The whip splice is wrapped with silk thread from E-F to G-H, Fig. 2 evenly. The weight of the spool supplies sufficient tension. This wrapping will overlap and secure the first end, and after the.wing of the base is covered, loosen the last two or three laps and insert the other end of the silk under them, pulling the laps tight. Shape the tip to take the (Continued on page 99) Popular Science Monthly DonTSwEATOVER ANTCHENSTOVE! ve! No excuseany more for fussing and and fuming or overs: hot No need of kee; a hot fire Z, a MT Eevee aneit (@ Amazing In Invention vi gf AY it off Instantly whew S A free. Suredt eaten SO Mave, SUE _ AGENTS Sry: Oliver agents scorn ao bigh epost atvecends aise” Wilts far Boece ues ‘the price ‘bas 8, not market }\. ues. i 75 year old diamond banking fi rm has thousands enpaid other bargains must sell NOW. “Why Pay Full Prices [MAKE ————— go phe “F 2 and qpare oe work’ ae ob at quar ter Sqatery cost. Order NOW from this ad. iltuetrated prospectus | bodies, tops, windshields mailed for 5c KUEMPEL CO., 86 KUEMPEL BLDG., GUTTENBERG, 1OwA] WIRELESS Head Receivers, Microphones, Keys, Jacks, Ete. ee COMPANY STATE AND 64TH STS., CHICAGO, U. S, A. you can earn from $1 to $2 an hour in your Spare time writing show cards, Quickly and easily learned by our new, simple “Instructograph” No canvassing or soliciting; we teach you how, guarantee you steady work at home no matter where you live, and pay you cash each w Full particulars and Booklet free AMERICAN SHOW CARD SCHOOL. 206 Ryrie Building Toronto, Can. — a Seale, Free amples GOLD SIGN LETTERS a F ama —— and office dows. Anyone can put — , ..-. Sees, Big demand. FFER TO GENERAL AGENTS. METALLIC LETTER CO., 433A N. CLARK ST., CHICAGO heels — = =) 45 be le 45 ope be —_-b 465 FF owe ee SO we 8 me rs he se OFS —~_ A oe fF we 45 45 mee et ee

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July, 1922

THE HOME WORKSHOP

Resilient Bait-Casting Rod (Continued from page 98) socket of the tip guide and set it in place with a good quality of waterproof cement, alining it with the two guides. Start at E-F (Fig. 2), and wrap to G-H to strengthen the splice. Finally, put in any decorative windings that may be de- sired. The cane rod handle is scraped and polished and the reel seat is fastened at the back end only. Then soft cord is wrapped and rewrapped until a firm yet resilient handle is built up to the shape desired. The rod is placed in the socket of the handle and pressed firmly home, the guides being alined with the reel seat. A hole is bored through the reel seat, the cane handle and the rod butt and a piece of soft wire is riveted through to hold the parts together. The ends of the reel seat are wrapped with cord and then the rod is ready for varnishing. Use only a brand known to be flexible and thoroughly waterproof. After the first coat becomes tacky, the knots are cut and the free ends wrapped closely around the rod; the varnish then holds them in place. At least three coats should be given; six or seven are better. In the photograph the reel is shown too far forward to suit most fishermen. Quickly Made Awning Will Shade Exposed Door Effectively ‘tm continuous piece of iron rod is bent to the indicated shape and, after the canvas is attached, it is fastened to the

AWNING ATTACHED TO DOOR OR ATTACHING CONTINOUS IRON ROD BENT TO ete FRAME AS BELOW

& ao. CANVAS Useful in many places, this awning costs little to make

door casing with heavy staples. An awning constructed in this manner, with a pro- jection of about 3 ft., serves to shade a gasoline pump beside a gasoline filling sta- tion. It cost practically nothing to put up, inasmuch as the canvas used was removed from an old automobile top.—G. A. LUERS.

Repairing Clothes-Wringer Rolls ‘TS rolls of ordinary clothes-wringers usually wear in the center. To repair them two methods may be used with little expense or difficulty. The first is to shave down the ends of the rolls until the diameter of each is constant throughout its length. This is possible only if the rolls are not badly worn. The best repair is to build up-the rolls with raw rubber, vulcanize them, and trim off the surplus. After removing the rolls, wash them with gasoline and fill the depressions by winding on strips of vulcan- izing rabber such as are used for repairing automobile tubes. Wrap strong cord around the fresh rubber, compressing it as tightly as possible and bake the rolls in an oven at 250° for one hour. The rolls are then trimmed with a sharp knife. Finish with fine sandpaper.—D. R. V.

BEST RETAIL TRADE

(Tratte Mark Reg US Pat Off and Foreign Countries)

ee ee ee qua

“B.V.D” Sleeveless Closed Cc Union Suits (Pat.

; ©The BVD’Red Woven Label ’ is the Trade Mark by which The BV.D. Company assures you the far-famed comfort, —— and dependable ity of its product. : The BV.D.Company New York “SOLE MANUFACTURERS OF “BV.D? UNDERWEAR rotch ae s| U.S.A.)Men’s$1.50the suit, Sapo ge ernest gee aaa

Page 86

aa 100 Price Prepaid $20: including 22% volt B battery, 150 feet of aerial wire and insulators. Hear Ye! Hear Ye! The World Speaks, Sings, Has Con- certs, Musicales, Operas, Sermons “Miraco’ Receives It For You The super-sensitiveness of the **Miraco” Vacuum Tube Receiver brings it all to you clearly in every detail. Made durable, attractive. Re- ceives on wave lengths from 150 to 600 meters. Connect phones, batteries, aerial ard ground and enjoy the music that fills the air. Only additional equip- ment needed is vacuum tube, phones and battery. Miraco Dealers Wanted Write for our good proposition now. Territory still open. You will be proud to represent Miraco in your community. The Midwest Radio Company Display Rooms 710 Vine St. Dept. C, 3423 Dury Avenue CINCINNATI, OHIO The Boy Craftsman Tells how to design and make many useful things. Many suggestions for indoor and outdoor pastimes. Price, postpaid, $2.65. Popular Science Monthly, 225 West 39th Street, New York City SINC Mr. Sorsinc Announces R. SORSINC an- nounces to his many friends in every | village and city in this country, and in many foreign lands, that in view of the greatly i in- creased demands made upon him, and his in- ability to serve so great a portion of the public directly, the Ship Owners Radio Service Inc., has decided to discontinue all retail and mail order service at New York, Boston, Philadelphia, Baltimore, New Orleans, San Francisco, and Seattle, and to devote its activities exclusively to wholesale at these points. The public will not lose sight of Mr. Sorsinc how- ever. He will soon begin to pop up in the windows of the most progressive and reliable radio dealers in every city in the country. He will thus be able to. extend his service, advice and consultation to mil- lions whom he has heretofore been unable to reach, by working through responsible dealers who con- duct their business according to Sorsinc standards. Wherever you see Mr. Sorsinc greeting you from a clean plate glass window, you may be assured of fair dealing, honest treatment and apparatus of quality inside. Mr. Dealer, have you met Mr. Sorsinc? FUP OWNER RADIO SERVICE 80 Washington St., New York THE HOME WORKSHOP Locking a Ford by Modification of the Ignition Key ie can rig up a lock that will answer the same purpose as a special Ford ignition switch lock without costing a cent. The trick is simplicity itself, yet it will fool anybody who tries to tamper with the ma- chine. The working part of the ordinary Ford ignition key consists of one central pin and two side prongs. Saw off the end of the central pin, as shown, and make a little ¥ FORD KEY SAW THIS PIECE OFF ~_ AND PUSH WOODEN PLUG plug of wood just = THE LENGTHOF SAME big enough to = INCENTERHOLE OF LOCK drive into the The central prong central hole of is sawed off the switch. Cut a piece of this plug the same length as the piece sawed off the key and push it into the hole the central pin of the key enters. When Mr. Smart Aleck comes along with his ordinary Ford key and tries to unlock the ignition to have a little joy ride at your expense, he finds that his key will not go into the lock far enough to turn. Your own key, which has been made just enough shorter to go into the lock and turn, will still unlock your own or any Ford not specially protected.—Jack L. BAKER. Irrigating the Small Garden with Overhead Pipes SMALL irrigation system for the garden may be built in such a way that the available water power is made to perform all the labor. The system consists of an overshot water- wheel connected with a small rotary pump by means of a chain drive. From the pump the water is piped to an overhead system of piping, from which the water is sprayed over the plants. The pipes are so placed that the sprays just meet. The sections of piping can each be shut off. The power nec- essary: to drive the wheel in this instance is ob- tained from water that flows through the spillway around a lock ina canal, but any source of water power may be utilized or wind power can be used; in the latter case a tank would have to be provided for the storage. of the water. The ends of the uprights that support the pipes are set in equally spaced holes in the garden. A wooden stake is put in each hole when the pip- ing is taken out in the fall, so that it is easy to replace the uprights in the spring. During the winter the water- wheel, pump and piping are all stored under shelter. The overhead sys- tem. of piping does not interfere with cultivating the gar- den because the piping is spaced well apart and the pipes are not put up until after the garden has been started.—G. E. P. The piping system Waterwheel and pump Popular Science Monthly ‘ “geet 5 Sa t \ \ BO ARANTEED ® Our Diamonds are distinctive iy in fiery weinasy. bine mnie. De GREE EXAMINATION, on SEND FOR FREE CATALOG There are over 2,000 illustrations . of Diamonds, Watches, Wrist Watches, Pearls, Mesh | Bags, Silvere PRICES ARE DC ware, etc., at Reduced Prices Catalog explains everything. Our IMMENSE BUYING POWER for our Chain of wa Stores in leading cities and enab! ag nage You will Se convinced that you_can do r wi : Lorre. oe back if oe 2? not ea' i filled, cae 25 years, 16 LIBERTY BONDS $20 is, warranted. Ribbon bracelet ACCEPTED AT PAR. with gold filled clasp, Special $21. THE NATIONAL JEWELERS FTli Dept.B-871 108 N. State St. io CHICAGO, ILL. BROS&COis8: STORES IN LEADING CITIES AUTO. OWNERS WANTED To To introduce the best automobile tires in the world. Made under our new and exclusive Internal Hydraulic Expansion Process mM that eliminates Blow-out— Stone- Bruise—Rim-Cut and enables us to 10,000 Mile Guarantee | we want an agent in every com- munity to use and introduce these jj wonderful tires at our astonishingly Hi low prices to all motor car owners. i Write for booklet describing this new fj process and nt our amazing introductory offer to owner agents. Hydro-United Tire Co. “ Dept. 74—Chicego San Francisco Pottstown, Pa. SEND FOR THE INTERNATIONAL CATALOG ist Factory Our net price list to > bodies and a. body sup4 direct WoL at BA saute PRICES. PROFIT Seve bi : buying DIREC For Ford and Chevrolet an from $27.88 up, FROM FACTORY INTERNATIONAL BODY WORKS 914 W. Ohio St., Dept.8, Chicago, Ill. BUCHSTEIN’S FIBRE LIMB soothing to your stump— strong, cool, neat, light. Easy payments. Braces for all Guaranteed 5 Years deformi- Send for Catalog Today. ties. P-BUCHSTEIN CO., 113 6th St. S., MINNEAPOLIS, MINN, RADIO FoR THE NATION Stores in five large cities enable this organization to supply radio equipment, both wholesale and retail, with the greatest speed and economy. 20TH CENTURY RADIO CORPORATION 565 Fifth Avenue, New York City Straus Building, Suite 710 Stores in Norwalk, Conn., Detroit, Mich., Newark, N. J., Brooklyn, N. 1. White Plains, N. ¥. A Torch with Hundreds of Profitable Uses TORIT ACETYLENE TORCH No. 13 Produces a Hot Instant Flame. For radiator and battery repairing, for ever wong | electrical connections, pots, pans,'etc.; for preheating fenders, tempering tools, vege 3 brass tubing, removing rusty bolts and nuts; for light brazing and hundreds of other uses. A Practical Outfit for Every Mechanic Uses Acetylene Gas Only Complete with 4 different tips and soldering $7 50 copper, rubber tubing and tank connection. ST. PAUL WELDING & MFG. CO. 164 W. $rd St., St. Pani, Mian. a a a 2, ee ee TT lh |

Page 87

nd 1s, ls, ts;

July, 1922 TUSKA PARTS SET

Type 223 Price $27.50 Wave Length, 180-500 Meters Many amateurs prefer to assemble their own sets and use their own ideas as to circuits, etc. TYPE No. 223 consists of all parts to make a receiving tuner, including drilled and engraved formica panel measuring 6” x17)”. Every item is a standard Tuska Product of highest grade and lend themselves to THE POPULAR SCIENCE MONTHLY’s regenerative circuit for which they furnish blueprint, as well as many others. Dealers and Amateurs—Send Five Cents for Catalogue No. 3. The C. D. TUSKA COMPANY 40 Hoadley Place, Hartford, Conn. RADIO PANELS tly to size and shipped within 12 hours. % “inch hee $.01 4c per ome inch, 5/16 inch .02c. Made of the highest oe black fibre. his material possesses high di electric strength, is inexpensive, unbreakable, easy to work and takes a nice finish. Special offer 6x6x14 .50c. We pay postage. RADIO INSTRUMENT & PANEL CO., Box 75, CICERO, ILLINOIS “BOWLEGSand KNOCK-KNEES” / | UNSIGHTLY y) iW SEND FOR BOOKLET SHOWING PHOTOS OF MEN WITH AND WITHOUT The Perfect Leg Forms PERFECT SALES CO.,140 N.Mayfield Ave., Dept. 45, Chicago, Ill.

DEAFNESS IS MISERY 1 know because I-was Deaf and had Head Noises for over 30 years. My invisible Antiseptic Ear Drums restored my hearin; 7 stopped Head Noiees, and will do it for you. ey are Tiny Megaphones. Cannot be seen when worn. Effective when Deafness is caused by Catarrh or b: Fortosated, Partially os Wholly Destroyed Natural —— Bn Be to ae in, easy to take out. Are “Unseen Comforts expensive. Write for Bookie and my pall statement of how I recovered my hearing. A. O. LEONARD Suite 301, 70 5th Avenue <= - New York City

Catalogue i; FREE catalogue tells you the kind of a Wireless Telephone to own, so that you receive inyour own home all the latest news, music, church services, lectures—everything broadcasted throughout the United States, Every home will soon have a wireless tele- phone outfit. We now offer complete outfits from $15 up. Everyone interested in radio should see our low prices on parts and accessories. Writefor this book. Learn about the miracleinvention ofthe age. Easy to in- stall, as simple to operate as a regular telephone. One copy of this booklet is yours, free, Write for your copy. Address Dept—R. 5 Montgomery Ward & Co.

Kansas City Chicago St. Paul

THE HOME WORKSHOP

How To Build a Boathouse that Floats on Pontoons + -¢-- 4 4 TUTE aa Tile |

SN, F COMPARATIVELY inexpensive construction is this floating boathouse. The construction is of the simplest type throughout, from the pontoons to the shed- like roof,so that any one with ordinary skill in handling woodworking tools can confi- dently undertake its building. The boat- house, as design- ed, will accom- modate a_ boat 36 ft. long and 10 ft. beam. The pontoons are nothing more

niet forges === than watertight LOAD WL: norma w:! boxes. The joints FRONT ELEV. should be beveled CLEAT- 2"*10"- BOLTED WiTH 4 "BOLTS INSIDE LINE OF PONTOON ae ~--. Pa -—- ~ -— --. <= lt tal WINDLASS

4 PUMP HOLE TIE

to form shal- ®00FinG Pape Bla low V-shaped : = seams, open Kk %4 IN Nac about in. on Ke the outside. 24° Fill them with _2 ps REMOVABLE oakum, driv- atl re wore nen Tn ing it tightly a= BOAT 23 SEAMS CALKED. PONTOON: PLANKING and calking CROSS SECTION iron. Parti- Trans and side stant, ptom, . s and cross section o tions stiffen om cca the pontoons and limber holes are cut to allow any water that may enter to run freely to the in with mallet pumps. Pad the iuside edge of the pon- | toons to prevent scratching the boat. The tie beam which prevents the pon- toons from straining out of alinement at the water gate is removed when taking out or putting in the boat. The inside | (Continued on page 102)

101

Radio Comfort The thrills of wireless entertain- ment in the home are enjoyed only where high grade receiving apparatus is installed. You can ensure the maximum of radio pleasure and comfort by insisting upon having your receiving outfit equipped with Stromberg-Carlson Radio Parts “‘Stromberg-Carlson Radio Head Set’’ —pleasing fit—quick adjustment—fine tonal qualities—ability to faithfully reproduce even the faintest long dis- tance signals. Stromberg-Carlson ‘Universal Radio Plug” should be attached to every Head Set. Fits any standard jack, takes any type or size of conductor; takes wire loops, tinsel loops, pin tips or spade tips, Stromberg-Carlson ‘‘Radio Jacks” are adapted to all standard radio plugs and are designed to mount neatly, without washers, on panels that are of varying thicknesses between 1/8 and 1/4 inches. Stromberg-Carlson Radio Products are backed by a firm that has had twenty- eight years experience in the design and manufacture of radio and telephone apparatus. Order Stromberg-Carlson Radio apparatus through your dealer in electrical merchandising or write for free Bulletin No. 1029-P. Stromberg-Carlson Telephone Mfg. Co. Rochester, N. Y.-Chicago-Kansas City-Toronto Address nearest office.

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after Ei dht Weeks Studv N ambitious salesman of Louisiana realized that in order to get along he must become master of his job. He enrolled for the United Y. M. C. A. Schools’ course in Salesmanship. His employer wrote ‘‘We observed that he was applying salesmanship principles to his work and getting effective results.” This young man stepped into a larger opportunity, after only eight weeks’ studying, and his commissions the first month in this new job amounted to $560. Few could expect so quick and such a large return, but every ambitious young man can fit himself for larger responsibility and earnings through spare-hour study with the United Y. M. C. A. Schools. Send for an inspiring booklet, ‘(Head and Shoulders Above the Crowd—How to Get There,’”’ tell us your age, occupation and ambition, and get our friendly counsel free. The “Six Reasons” for studying with the United Y. M. C. A. Schools will appeal to you. Tear Out and Send This Slip United Y. M. A. Schools’ Correspondence Courses, or positions for which they afford training: Accountant : Advertising Man Own-Your- ¥ " Agricultural Courses Home Course { Architect Machine-Shop Practice Mechanic Leadership Courses tive Operator Mathematical Courses Mechanical Engincer lumber Poultry Husbandry Radio Operator Radio Engineer Railroad Engineering Salesman Secretarial Shorthand and Typewriting Ww Business Organization Civil Engineer Civil Service Concrete Engineer Dairy Farming Draftsman Steam Engineer Electrician Structural Drafting Electrical Engineer Surveyor Factory Management Tool Design: Farm Management Tractors and Farm Foreign Languages Machinery High School Subjects Traffic Management Foremanshi Use of the Slide Rule hip Highway Engineering Are You an ex-Service Man? United Y.M.C.A. Schools “hewyok ci” Without obligating me, please advise regarding the course in in the Home . interesting book written in non technical i pemane oot man uying a small Radiophone Receiving Set t B listen to Opera, News, Reports “s Concerts, etc., by » Lectures, |. Lee DeForest, Ph.D., D.Sc. the world’s foremost inventor and pion ; Radio field. Contains : Explanation Of oe of Wireless, lts Value in the Home, Essentials of 4 Receiving Station, How to Erect an Antenna, Pur- poses and Uses of Equipment, The Amplifier. []- lustrated with Photographs and sketches. Covers anything you will want to k: ‘Wi Send 15¢ for it now. now about -Wireless. DeForest Radio Tel. & Tel. Co. Central Ave. & Franklin St. d City, NJ. Popular Science Monthly THE HOME WORKSHOP How to Build a Boathouse (Concluded from page 101) face of the beam acts as a bumper for the boat and should be padded. Regular house construction is used for the frame. The roof will weather well if merely painted, but a covering of roofing felt makes a more durable job. A length of old spar or a roller may be used for the windlass. The split bearing, IRON PIPE 6" DRUM 5 20FT CHAIN made as shown, permits the roller to be removed at any time. The rope sling should » becovered with old fire hose or other- wise padded. For light craft a single- BOAT WINDLASS Details of the pontoons, block tackle may boat windlass, tie beam, and anchor be rigged up; for a heavier boat, a double-block tackle is advisable. The house should be moored with the door to leeward. A box, washtub, or special form may be made and filled with scrap iron and concrete. The two eye- bolts are embedded and a chain bridle rigged up, as shown. About 20 ft. of heavy chain between anchor and cable is advisable, although wire rope alone can be used. Wire rope }4 in. in diameter is heavy enough. Two 300-lb. or heavier anchors should be used, with cables leading to the corners of the house. Let the an- chors stay down permanently and mark their location with wooden spar buoys or pick-ups when the house is moved.—C.S.T. A Soldering-Iron Holder MECHANIC is often at a loss where to lay his hot soldering-iren. He would not hesitate if the iron had a holder similar to the one shown. It is made of a heavy strip of brass and is so constructed AEGS N USE The legs fold back . out of the way that it can be folded up when not in use. The two legs hold the iron a little above the bench where there is no danger of any- thing catching fire. To make the holder takes but a few minutes and it will save a lot of time.—W. C. ROYER. Buys this world- famous Elgin Watch—the watch you can rely upon every second of the day. Itisanew, thin, open - face dust-proof model, 12 size movement. Handsome gold-filled case, guaranteed for 20 years. Only $13.98—no advance over the standard Cash So amazingly low credit terms only 2.98 upon receipt and $1 a month for 11 months. Buy it now! De Luxe Catalog Free Contains the most won- derful assortment of Watches, Diamonds and other jewelry. Send for nad copy today. Address pt. 472-M. Capital,-$1,000,000 “The House of Quali os L.W. SWEET inc New York 1650-1660 Broadway | FORDS run 34 Miles on Galion of Gasoline Wonderful new carburetor. Guaran- ye tart easy in coldest weather. - Sent on 30 DAYS’ TRIAL make as high as $6 mie to — ‘Other oly tilda saving. Send eof car and take advan- of our special 30-day offer. Agents Wanted. AIR FRICTION CARBURETOR CO. 8480 Madison Street Dayton, Ohie Big Band Catalog Sent FREE Anything you need for the band— single instrument or complete equipment. Used by Army and Navy. Send or big catalog, liberally illustrated, fully de- scriptive. Mention what instrument interests you. Sold by leading music dealers everywhere, Gree —*t | ¥ LYON & HEALY PAYMENTS 57-86A Jackson Boulevard CHICAGO “RADIO TELEPHONY FOR AMATEURS” By STUART BALLANTINE Formerly Expert Radio Aid U. S. N. is the book that tells the how and why of radio telephony. Written so you can under- stand it fully. The biggest help to the amateur operator. 200 pages, fully illustrated. $1.50 net, by mail $1.65 SEND FOR YOUR COPY DAVID McKAY COMPANY PHILADELPHIA IMMEDIATE DELIVERIES — POST PAID Audibility Unsurpassed—Money Back if Dissatisfied Antenna Wire—7 Strand Tinned 150 Ft., $1.60 TOWER MANUFACTURING COMPANY 3 STATION ST., BROOKLINE, MASS. Dmeastnwe Sasconne Ifans f ——-j) og f pee~U Rees ee a first and favo ioe

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July, 1922 Jimmy’s Diary Saturday, June 3rd “Our Boy Scout troop on 16 mile bicycle ride today. Frank Norton got a punkture. I had tube of Neverleak Tire Fluid in my first aid kit. Squeezed Neverleak in his tire d stopt the leak instantly.” seein . jimmy. Neverleak has saved many a delay. It’s the old favorite — guaranteed satisfactory or money back. 25c a tube at all bicycle and repair shops. FRE E~Sen4 ‘or handy Neverleak Pencil Clip. In attractive colors, holds pencil firmly in place. Buffalo Specialty Co. 115 Ellicott Street Buffalo, N. Y. NEVERLEAK TIRE FLUID “HEALS PUNCTURES ON THE RUN.’ mae You can earn $15 to $50 a week wri show cards in your own home.—No can ng.—A soos profitable profession easily and quickly learnt by our new simple graphic block system. Artistic ability not necessary.—We teach you how, and supply you with work—Distance no object. Full particulars and booklet free. WILSON METHODS LIMITED— DEPT. C 64 East Richmond, Toronto, Canada. AGENTS q fe: YOU CAN SELL THIS FO SENS ay i naan eT with spring tension device MY! HOW THEY SELL! ONLY 20 Boxes a Day Means $18.00 Daily Profit! You get the interest with the free Shears. Walter Harris Sold 800 boxes in 6 Weeks. Profit over$100.00 aweek. A total retail value of $4.60. Areal bargain at $1.75. ACT NOW! Sells like hot cakes year ’round. A baby could sell Lucky 11. Don’t delay a minute. Save time. : , Send $1.75 for complete outfit including display case, Atleast write for circulars explaming. our unique plans, including 30 other packages. Act Now. E. M. DAVIS CO., DEPT. 2367 CHICAGO, ILL. THE HOME WORKSHOP Simple Hoist for Delivering Cement to Second Floor T= hoist rigging here shewn is a prac- tical application by a local builder of a lever lift used in placing a cement porch on the second floor of a building. The usual practice is to hoist the cement hand over hand with pulley and rope. In this instance a vertical support was placed near the porch, bearing a com- bined swivel and pivot joint connecting CONVEYOR HOISTED AND SWUNG AROUND FOR DUMPING ‘COMBINED \ SWIVEL AND PIVOT JOINT VERTICAL CEMENT PAIL A pull on the rope raises the pail of cement, which then is swung over the platform with the lever, which was a “‘two by four” about 16 ft. long. At one end a large pail was fastened and a rope at the opposite end was used for hoisting. The pail, when empty, practically bal- ances the beam and lowers automatically for refilling. When the filled pail is hoisted, the lever is turned about on the swivel and swings the pail in on the platform, where it is dumped.—G. A. L. Splicing Electric Wires OUR of the most efficient methods for joining electrical conductors are shown in the accompanying diagram. Figures A and B are twisted joints, the second being more quickly made, but not so strong as the first. In C the wires are shown held together with wire rope clamps. If the space be- e—e= — Cie — ae, ea Four joints that are good connections electrically and mechanically tween the clamps is well soldered, this joint is good for temporary purposes, since the wires may be taken apart quickly. A more durable joint is shown at D, where the wires are twisted and clamped. All these joints have to be well soldered to be of highest value.—B. H. W. “The daily program way TALES , ¥ { & ee / ORE wonderful day by day grows the range of entertain- ment, recreation and information supplied by casted in all All you require to enjoy these pro- grams in yourown homeis a receiving set equipped with the Magnavox Radio. With it, it 1s possible for the entire family to hear all that is in the air as if it were being played by your phonograph. Any radio dealer will de- monstrate for you, or write to us for descriptive booklet and name of nearest dealer. The Magnavox Company Oakland, California New York Office: 370 Seventh Ave. enn. Terminal Bldg. [= it MAGNAVox that comes to you Brain Without a Magna- vox Radio no wire- | less receiving set is a complete. radio programs broad- parts of the country. tells it um)

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104 Popular Science Monthly PATENTS SECURE A PATENT, send for Our Guide Book, HOW TO GET A PATENT, sent Free on request. Tells our Terms, Methods, etc. Send model or sketch and description of your invention and we ee ee) 0fieien eo to ie nonce mmwemesmeaemoed patentable nature. RANDOLPH & CO. 130 F St, N. W, Washington, D. C. ; : IF YOU HAVE AN INVENTION and DESIRE TO LEARN HOW TO SOROS O SESS EET EEE EHO EES OSES EEE EES OE EE® PATENTS Booklet Free Highest Referenees Promptness Assured Best Reeults Send drawing or model for preliminary examination of Patent Office records and repert as to patentability. All Business Given Prompt and Proper Attention WATSON E. COLEMAN, Patent Lawyer, 624 F St., Washington, D.C. RADIO And Other Electrical Inventions Patented Mason, Fenwick & Lawrence PATENT LAWYERS Washington, D.C. Established 1861 We have with us four late members of the exam- ining corps of the United States Patent Office. Other offices: New York, Chicago, Denver, Seattle, Trade marks registered in United States and for- eign countries, Ideas developed. ‘a RICHARDSON & ROGERS, 8 Albee Bldg., Washington es, PATENTS PATENTS TRADE-MARKS COPYRIGHTS Send for our free book of patent information Beale & Park %5Si:s"sises.2,¢ THE HOME WORKSHOP Automatic Gage for Sawing Circles made. From a -in. board cut a circle of any convenient size and chisel a slot in the center for the saw blade. On four different radial lines lay off scales that will represent certain diameters. On the first, for ex- ample, lay off a series of points that will give circles of 1 in., 114 in., 2 in., 214 in., CUTTING TABLE ~ The work Pivots on a lug A, which is etc., when the device is used as shown in the illustration. The actual measurements from the center will be half as much, or 4% Send us sketch or model for Soteptabiity upinion and exact cost of patent. Our boo! How to Obtain a Patent” Sent Free on re- to ly for Patents, Trade Marks, ts, hts, etc.; gives information on Patent Procedure; tells what every inventor should know. Th ds of I ‘3, who are our clients, are our references. - CHANDLEE & CHANDLEE, 25 Years’ Experience 427 7th St. . Washington, D. C, in., 4% in., lin., 1\% in., ete. Do the same on the second line for circles of 114, 134, 2%, 2% in.; on the third for 1%, 15%, 2% in., etc.; on the fourth for 134, 17%, 23% in., etc. At these points drill %-in. holes. Make a sharp-pointed lug to fit them snugly. with countersunk wood screws. When it is desired to cut a circle, the lug is placed in ATENTS and TRADEMARKS As onc of the oldest patent firms in America, and —— a clientage extending to all parts of country, we afford Inventors and Manufacturers, + — charges. a tn a or and results.evidenced by many well- known Pals and Trade Marks of exracrdinay valte Lacey &Lacey, 648 FSt,Washington,D.. ES TABLISHED 1869 Our book Patent Sense - Free the proper hole and the piece of wood to be cut is pivoted on it. The wood is then re- volved against the saw, the circle being automatically generated. —HuUGH CARD. | CAN YOU think of a simple, practical idea that will fill one of the many ree quests we have on file for new invene tions? It may mean a fortune for you. Thousands of things are needed Ricut Now. Your brainscan help. Send to. day for our great new book—“‘Invene tions and Trade Marks, Their Protection and Exploitation’’ and learn more about making money from ideas than you ever knew before. It tells many things that are wanted, t0O. A postal will da— it is free. We help our clients, Without charge, to get fine cnce cates fa _ ADVERTISED one others possess. For SALE FREE Advice free. In INVENTION And usa MANUFACTURING ahaa SUPPLEMENT. INDUSTRIES, INC. Published for the man with an idea. Send for free sample copy. One year’ssub- 6cription 50c. 203 Patent Dept., WASHINGTON, D. C. PATENTS | PATENTS To the Man With an Idea (2) I offer a most comprehensive, ex- perienced, efficient service for his prompt, legal protection and the development of his proposition. Send sketch, or model and description, for advice as to cost, search through prior United States patents, etc. Pree liminary advice gladly furnished withe out charge, My experience and familiarity with various arts, frequently enable me to accurately advise clients as to probe able patentability before they go to any expense, Booklet of valuable information and form for properly disclosing your idea, free on Tequest. Write today. RICHARD B. OWEN Patent Lawyer 6 Owen Building, Washington, D.C, _2276-D Woolworth Building New York City work are usually countersunk to overcome the crystallization that may result. A large boiler shop at Waukegan, Wis., has adopted a small shopmade tool for doing this work. It consists of a pneumatic drill mounted upon a hand truck sé that it can swing in the direction of the travel of the truck. By its use the company has reduced fatigue and accelerated production. The counter- sinking is done uniformly in shorter time for lower cost. wide, and 1 ft. high. The pneumatic drill is located at the front of the truck and is carried through the bottom of the truck body on a swivel joint.—K. R. on Scroll- or Fret-Saw CIRCLE-CUTTING attachment for a scroll- or fret-saw may easily be TO FIT HOLES placed in a hole that gives the correct radius The fixture is attached to the saw table Countersinking Rivet Holes in | the Boiler Shop | UNCHED holes in metal fabricated work for boilers, ships, and similar | PNEUMATIC ORILL WEIGHTS HANOLE SWINGING LEG The drill is mounted on a small truck for ease in handling This tool requires little skill or strength. The truck used is about 3 }4 ft. long, 2 ft. o> A wt et ee ee Le Le LL lL

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July, 1922 THE HOME WORKSHOP Automatic Toy Sand Dump Will Amuse the Children By Charles M. Miller eae children delight to play with sand and it is almost as much fun for mechanically inclined grown-ups to make sand toys of wood and metal. One of these interesting toys is the sand dump illustrated. First make a trestle incline and a frame- work to carry the weight cord. The weight travels the same distance as the car on the incline, so the height is dependent on the length of the track. The base must be large enough to prevent the apparatus from tipping over and is further steadied by burying the bottom members a little way in the sand. The car is built so that the body remains level while on the incline. Wooden buttons The car travels up and down the incline until the hopper is empty 1 in. in diameter make good wheels; tin roofing nail caps are sometimes used. Small wheels may be cast of Babbitt metal or turned on a lathe. If the bottom of the car is made of wood lf by 2% by 8 in., the rear wheel block can be nailed from the upper side and the sides of tin or light weight galvanized iron can be tacked around the outside. As shown, the sides and end are made of wood and the bottom is of tin. The body can also be made entirely of metal. The wire trip is attached to the rear end of the car, soldered to a metal body or stapled fast toa wooden one. The base is made with two feet, 7% by 3 by 12in. One standard is % by 8 by 26 in. and the other % by 3 by 4in.; both are let into the foot pieces. A 34-in. dowel makes a good connecting brace. The incline is ¥ in. by 3 in. by 25 in., screwed or nailed to the standards. Pieces 44 in. thick and 34 in. wide are nailed to both sides of the incline; the extra 4 in. is left above the board to guide the car. The hopper may be made of metal or wood. The pattern for one of metal is shown; the flap should be soldered or riveted. If made of wood, the length of all sides would be 4in. Two sides will be 4% in. at the top and % in. at the bottom, the other two pieces being 4 in. at the top and 34 in. at the bottom. The trap prevents the continual flow of sand while the car is down theincline. Itis a little scoop hinged to the sides of the hopper. When the car ascends, the wire tripper strikes the under side of the right end of the scoop, pushes it back, and tilts it (Continued on page 106) 106 ERE RAR RARER COPYRIGHTS wd es FREE OPINION AS TO SPECIAL OF F E PATENTABLE NATURE Before disclosing an invention, the inventor should write for our blank form ‘‘Record of Invention.’’ This should be signed and witnessed and if returned to us together with model or sketch and description of the invention, we will give our opinion as to its patentable nature. Our Three Books Mailed Free to Inventors Our Illustrated Guide BOOK HOW TO OBTAIN A PATENT Contains full instructions regarding U. S. Patents. Our Methods, Terms, and 100 Mechanical Movements illustrated and de- scribed, Articles on Assignment or SALE OF PATENTS, Patent Practice and Procedure, and Law Points for inventors. OUR TRADE MARK BOOK Shows the value and necessity of Trade-Mark Protection and gives information regarding unfair competition. OUR FOREIGN BOOK We have Direct Agencies in all Foreign ' Countries. Write for our illustrated Guide Book on Foreign Patents. Send for List of Patent Buyers containing unsolicited Letters from Manufacturers and others Wishing to Buy Patents. SPECIALIZATION Our Staff The field of invention is so vast that it is impossible for any one to become an expert in all the different classes of invention. Only those skilled in the class to which the invention relates are capable of rendering efficient service. For this reason Victor J. Evans & Co. employ a number of patent lawyers and mechanical experts who have been selected for their special knowledge and ability in certain lines of invention, Each case is placed in charge of experts in the classes to which the invention relates, THE VALUE OF YOUR PATENT Will depend much upon the skill and care with which your case is prosecuted in the United States Patent Office. We spare neither time nor pains to secure the broadest possible patents that the inventions will warrant. That every case entrusted to us receives our best efforts, and that our work is done consistently, skillfully and thor- oughly is evidenced by the many unsolicited letters of commendation that we receive constantly from our clients. We will furnish upon request lists of clients from any State in the Union for whom we have secured patents. Our New York, Philadelphia, Pittsburgh, Chicago, and San Francisco Offices Owing to the growth of our business we have established for the benefit of our clients Branch Offices in New York City, Philadelphia, Pa., Pittsburg, Pa., Chicago, Ill., and San Francisco, Cal. These her offices being located in these large commercial cities, together with our Main Office located near the U.S. Patent Office, in Washington, enables us to more promptly handle the business of our clients, par- ticularly as the branch offices are in constant touch with the Main Office and fully equipped to handle patent business in all its branches. Highest References—Prompt Attention—Reasonable Terms eal saa) | i VICTOR J. EVANS & CO. Patent Attorneys New York Offices Philadelphia Offices Pittsburgh Offices 1007 Woolworth Bldg. 714-715 Liberty Bldg. 514 Empire Bldg. Chicago Offices. 1114 Tacoma Bldg. San Francisco Offices, Hobart Bldg- Main Offices, 760 9th Street, Washington, D. C. Gentlemen: Please send me FREE OF CHARGE your books as described above. Vi, {| if | | | | | el i “ D}i laa Er hil tre ee ee a ee ea re ae ae

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Popular Science Monthly The Hour That Counts! When you see a man putting in his noon hour learning more about his work, you see a man who won’t stay down. He’ll never be satisfied until he hits the top. And he’ll get there! In shops, factories, offices, stores, in every line | of industry, men are holding splendid positions | won through spare time study with the Inter- national Correspondence Schools. Today they are earning four or five times—yes, some of them ten times as much money as when they started. Employers everywhere are looking for men who really want to get ahead. If you want to make more money, show your employer that you're trying to be worth more money. For 30 years the International Correspondence Schools have been training men and women right in their own homes. More than two million have stepped up in just this way. More than 130,000 are studying now. Can you afford to let another hour pass without making your start toward something better? Here is all we ask—without cost, without obli- gation, mark and mail this coupon! INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7693-B, Seranton, Penna. Without cost or obligation on my part, please send me full particulars about the subject before which I have marked an X in the list below:— BUSINESS TRAINING DEPARTMENT. Business Management []Salesmanship Industrial Management [ jAdvertising (Personnel Organization [ ]Better Letters Traffic Management [jForeign Trade Business Law [jStenography and Typing O)Banking and Banking Law [}Business English f) Accountancy (including C.P.A.) L)Civil Service ONicholson Cost Accounting [ }Railway Mail Clerk Bookkeeping [JCommon School Subjects Private Secretary []High School Subjects Business Spanish [French (illustrating TECHNICAL AND INDUSTRIAL DEPARTMENT Electrical Engineering [jAirplane Engines HElectric Lighting [} Architect (0 Mechanical Engineer [JContractor and Builder {jMechanical Draftsman [J Architectural Draftsman Machine Shop Practice [}Concrete Builder Railroad Positions Structural Engineer OGas Engine Operating Chemistry LiCivil Engineer Pharmacy LiSurveying and Mapping L_] Automobile Work Mine Foreman or Engineer [J Agriculture and Poultry Steam Engineering [Wireless U) Mathematics INI 5-5 osucusincpencobnsabesupnesessuunbbbbanebsbiesbpoanbesabesccsesueosss Persons residing in Canada should send this coupon to the International Correspondence Schools Canadian, Limited, Montreal, Canada, “THE Vest Pocket Lawyer’’—a complete law course— clearly analyzed in understandable English. It is a daily guide—a manual of reference for the business man—the law student—the justice of the peace—the notary public— the farmer—the clergyman—the merchant—the banker, the doctor. 360 pages, 112 legal forms. Price, tpaid, , — Science Monthly, 225 West 39th Street, New York. wera ee tl | ae SS SS you have an idea to patent send form" INVENTORS RECORD” which contains instructions for proceeding. -Personal Service - WH MULLIGAN. PATENT LAWYER THE HOME WORKSHOP 7 free “PATENT ADVIC Ee and for 203 Woodward Blda. Washinaton. D.C. Automatic Toy Sand Dump (Continued from page 105) so as to allew the sand to run out. At the bottom of the incline is a piece of metal to stop the car in such a way that the sand will be discharged. The grooved pulleys may be turned, or a short length of dowel sawed off square and fitted with flanges will answer. A screw eye can be cast in the weight. The sand is poured in the hopper by hand. Some of the sand runs into the trap and blocks the rest, but when the car as- = DETAIL OF METAL CAR ~ - “eee HOPPER PATTERN A DETAIL OF “ao TRAP pa oe ~ PULLEY p--ennnn--—f-4 re BRACKET + - ‘ S c are, ° " DETAIL OF Lp lq 27" TRIPPER Details of metal parts and tripper arm cends, the trap is tipped and the sand falls into the car until enough has run in to more than counterbalance the weight. When the car starts down the incline, the trap drops ' forward and shuts off the hopper. As soon as the car strikes the abrupt incline at the bottom, the body tips and the sand runs out. The car is again lighter than the weight and is pulled up to perform the same operation as long as the sand holds out. The weight should be heavier than the pull of the car, but not as heavy as the loadedcar. | Some little adjustments may be found necessary before the apparatus works smoothly. If the drop is too sudden at the bottom, the weight will not raise the car back; if it is not sufficiently low, the sand will run out too slowly. The amount of weight cannot be estimated in advance, as different mod-Is will have different amounts of friction to overcome. Handy Bottle-Cap Remover A STRONG bottle-cap remover for the kitchen or for picnics, where many caps have to be removed at one time, may be made from a piece of %-in. hard wood gece Made from a piece of =e hard wood and a wood screw about 6 in. long and a wood screw. The handle should be shaped as shown and a hole drilled at an angle into the end of the jaw to take the screw.— WILLIAM E. KING. Radio $1 950 Receiving Set for only ond including Constat Headphones All the wonderful entertainment of the radio programe on dandy set. mprises double slide tuning coil, adjustable crystal detector, condenser and Constat headph all ted ready for use. st materials, carefully made, thoroughly tested. You couldn’t possibly make this set yourself for less than $15. You can get it complete for just $12. Seperaly Phones sogy Outfit $f 250 ez Aerial Outfit 100 feet Stranded Copper Wire 6 composition 65 insulators - This wire sells anywhere for 85c and the = 14 your door, ready for making your aerial, for just $1.65. Save time, labor and con- siderable money. Send pos- eS or a money ee very m nteed to give satisfaction. BANISTER & POLLARD 209 Market Street, NEWARK, N. J. It’s Easy to Build Things with a Junior Bench Saw D®°ES your ripping, mitering, grooving, rabbet- ing. tenoning, sanding, grinding and man other operations with surprising ease and accuracy. Top 10//x13//. Saws 1 42// stock. Driven by a Se or 1/3 hp. motor. Portable. Run from any light socket. All metal construction. Ex- “"“Wececietive sivontar toll things of scriptive cular is many ings of interest to workers fn wood and soft metals. _ a $28 5 Junior Bench Saw only, with guides and one 6// saw blade, 3 Price complete with ‘4 hp. Ball Bearing motor as shown, $60.00. W. & J. BOICE, 112 23rd Street, Toledo, Ohio 1/4,H. P. Ball Bearing Motor with cord and plug and grooved 4 or flat face pulley. (New) 110 Volt 60 cycle A.C., $15.50 32 or 110 Volt, D.C.. .16.90 By parcel post to your door CO. Motors guaranteed 1 year. CONVENIENCE MFG. CO. 5902 Maurice Ave. Cleveland, O, ro roENY THIS CER DON’T LOSE YOUR RIGHTS TO PATENT PROTECTION Before disclosing your invention to anyone send for blank form *‘EVIDENCE OF CON- CEPTION” to be signed and witnessed. A sample form together with printed instructions f will show youjust how to work up your evi- dence and establish thesame before filing ap- plication for patent. As registered patent at- torneys we represent hundreds of inventors all over the United States and_Canada in thead- vancement of inventions. Ourschedule of fees willbe found reasonable. ‘The form “Evidence of Conception,’”’ sample, instructions relating to obtaining of patents and schedule of fees sent upon request. Ask for them,—a post card A will do. PATENTS AND \ TRADE MARKS 274 Ouray Bldg. WASHINGTON, D. C. Originators of forms ‘Evidence of Conception.” If ille sh alc

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THE HOME WORKSHOP Knots that All Fishermen Will Frequently Find Useful HE hitch shown in Fig. I is excellent for connecting the line to the loop of the gut leader. Generally the fisherman makes a solid knot and often has to cut it off and make a new knot, but: this one, while it holds well in service, will come undone when the short end is pulled. In Fig. II are shown three methods for connecting either the line or the gut leader to the hook. The knot at a is one that should recommend itself to the fisherman FIG [ FIG. If (a) (b) (oc? RADIO. FIG IL (d) ¢ o (ed Connecting line to leader and line or leader to hook on sight; it is simple and cannot come un- done. To loosen it, push on the long end of the line. The knot at bis another good one. Put the line or gut through the eye as shown and draw tight. Do not clip the spare end too close. The same principle is involved in the knot at c, except that two loops are thrown around the hook shank. The so-called turtle knot, with which many fishermen are not familiar, is shown in Fig. III. Slip the end of the gut through the hook as shown at d and loop it; then extend the loop over the hook, as at e, and draw all parts tight. Anglers will find this a good hitch for attaching the fly hook to the leader.—ROBERT PAGE LINCOLN. To Fold a Hike Map Handily (y= of the United States Geological maps makes an excellent hiking guide, but is awkward to carry when rolled up. If it is creased or folded, it soon becomes illegible, especially at the creases, and in a short time falls apart. To obviate these drawbacks, cut the map along the rectangular division lines and lay Lega MW de PARTLY FOLDED RV Ne I7T Wy a) The map is cut into sections, mounted on muslin and folde them face up on a piece of linen or muslin a trifle larger than the map. White photo- graphic paste should be applied to the linen and the cut sections of the map stuck on one at a time, leaving a 1/16-in. to \%-in. space around each section. The scale of miles should be cut off and pasted on the back, as illustrated.—A. E. Z1IpPRICH. Use Borax Freely in Brazing Te DO a good job at brazing, immerse or thoroughly wet the work in a saturated solution of borax and hot water. While heating, apply powdered borax freely. 1, ‘‘F-E’’ hematite, Transformer. An audio frequency transformer, designed to give maximum amplification without distortion, and suita- » ble for use with high a amplifying vacuum tubes. Model 120, $7.50 2. “F-E’? Universal Radioplug. This plug has innumerable use in vacuum tube receiving and sending sets. Can be used with spade tips, pin tips or solid wire a No parts to lose or break. Model 103, $1.7 3. “F-E’’ Telephone Socks. For use in amplifier, loud speaker and similar appa- ratus. Model 116—Open Cheoute ome * 55 Model 117—Closed Circuit 75 Model 118—Two Circuit 4. ‘“‘F-E’’ Junior Antenna Insulator. For radio receiving Antennas. Made of ciesed porce- lain, Substantial and rugged. Model 145—$0.2 5. F-E’’ Radio Tube Socket. Aluminum shell, German silver contacts, insulated base. Especially adapted for radio as well 3 entio frequency amplifiers, detectors, etc. Price, of the above parts are guaranteed to give satisfaction. ‘arts. Are you one of the hundred thousand people who are about to build your own radio outfit and get in on the most fascinating sport in the world, It is easy to build your own receiving set and it can be done at a low cost and will give absolute satisfaction pro- vided the materials and parts which you use are correctly designed. Freed-EisemannApparatusis DesignedbyEngineers Who Designed Apparatus Now in Use by U. S. Navy The following parts are of the finest quality material designed by experts to give perfect results in radio apparatus. and they will be shipped immediately. “F-E’’ Radio Telephone Antenna Outfit. Complete antenna equipment; may be used with any radio receiving set. fit comprises all necessary antenna wire, in- sulated wire, switches, ground clamp and sim- ple instructions for putting up. Model 128. ARE YOU BUILDING A POPULAR SCIENCE RADIO OUTFIT? Thousands of people have ordered PoPULAR SctENCE MONTHLY’s Blueprint to make their own radio outfit. All Order from your dealer to-day. Demand Freed-Eisemann If your dealer has not yet received his stock, send money-order or check direct to us. FREED-EISEMANN RADIO CORPORATION 251 to 255 Fourth Avenue New York City Manufacturers of the Nationally famous ‘‘Marvel” $ 5 00 Complete with phone and aerial equipment....... . PARTS Order these parts by number This out- $2.50 6. “‘F-E’’ Dubilier Pn Ae These are built of the best mica and pure tin foil. The condensers are compressed and impregnated in paraffin. Capacities are permanent and losses ex- tremely small. Price, $0.35. 7. ‘‘F-E’’ Condensers. Made of pure tin foil and special dielectric material. For use in crystal or tube circuits. Model 106—Grid Condenser, capacity 0.0005.... $0.30 odel ne Condenser, capacity WR NEw cope ciensderaetewckwa meas 8. ‘“‘F-E’’ Rheostat. For surface or back of panel mounting Maximum resistance about 6 ohms; carrying capacity 2 amperes. Can be used in filament circuit of two vacuum tubes in parallel. Model 139, $1.25. 9. “‘F-E’’ Dubilier Condensers. Same internal construction as No. 6. Is supplied with spring clips and holder for grid leak or Crystal detector. Price, $.7 choice of 44 $ 1 d sizes of thet famous eames Bicycles. Express pre- i d. Low Factory-' Pay Prices. the small monthly ly payment io — Tae cee eis ora ol 60 Gee d to jo you F Your a ' Mead Perfect hearing is now bein stored in every condition of deat p ness or defective hearin ’ causes such as Catarr ban ness, Relaxed or Sunken Drum Thickened Drums, Roaring an « Hissing Sounds, Wholly_or Partially Destroyed Drums,Discharge from Ears, etc. Wilson inti Ear Drums **Little Wireless Phones for the Ears’’ require no medicine but effectively replace what is lacking or defective in the natural ear drums, are simple Gevices, which the wearer easily fits into the ears a ey are invisible. Soft, safe and comfortable. Write today for our 168 page FREE book on DEAF: NESS, giving you full particulars and aac ogaa WILSON EAR DRUM CO., In corparated 939 Inter-Southern Bldg. LOUISVILLE, KY. The Real Estate Educator This book gives a most comprehensive yet most concise arrangement of useful facts about buying, selling, teasing and sub-letting of Real Estate, contracting, for erection or re- = mortgaging, transferring, insuring, etc. Cloth, 256 ges. Price $2.00, postpaid. Popular Science Monthly, 538 West 39th Street, "New York City. Free Book Containing complete / story of the origin § and history of that wonderful ins' ment—the S This book tells you when to use Saxophone— singly, in quartettes, in sextettes, or in regular band; how to pond from cello parts in orchestra many other one you would like to know. Saxophone is the easiest (yam of all wind | ale toplay. Youcan } learn to play the scale in an hourand soon be playing popular airs, It will double our and your popu arity. eo t lessonssentfree. Nothing can take e of the Saxophone for Home Entertainment, Church, Lodge or School, or for Orchestra Dance | Music You may try any Buescher Saxophone, Cornet, Trum: Instrument 6 days, | If satisfied, bay for it, rt by onsy mn kk. SUESCHER BAND INSTRUMENT CO. Makers of Everything in Band and Orch 314 Buescher Block ELKHART, IND. Naw To Radio Dealers insulating properties. 3/16 inch and 34 inch thick. class sets. RADION Hard Rubber resists warping. RADION xaceser Panels and Parts Preterred for high- Costs no more than materials which have inferior RADION sheets in black, brown, and mahoganite (mahogany grain) RADION standard Dials, Sockets, Bases, Aerial Insulators, Knobs, Tubes, Switch Handles, Storage Battery Jars and Parts, large tubes for Variometers, Rods and all standard moulded parts, Dealers write at once for information American Hard Rubber Compan 11 Mercer Street New York,N.Y.

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108 Popular Science Monthly

Even a Machine Needs a Prod! A counter— like a con- science — tells what your machine ought to do, to do right by its owner. It tells what the operator ought to do, to do justice by his employer. It wipes out the discrepancy between the production you now get and should get!—this checking-up by a COUNTER You can get a “Veeder” for every machine where results are increased through accurately recording them. The Set-Back Rotary Ratchet Counter below is for machines such as punch presses and metal stamping machines, where a recipro- cating movement indicates an operation.

Registers one for each throw of the lever, and sets back to zero from any figure by turning knob once round. Supplied with from four to ten figure- wheels, as required. Price with four figures, as illustrated, $11.50—subject to discount. (Cut less than 1% size.) Set-Back Revolution Counter of similar model, $10.00 (list). Speed Counter Here’s the handiest instrument for finding revolutions-per-minute of a shaft or flywheel. You hold the tip of the counter against end of revolving shaft; press lightly when the second hand of your watch comes to O; release pressure when minute is up. A spring clutch controls the recording mechanism. | (Cut less than 1 size.)

4 tn tian i: eb im i sg The Veeder Speed Counter enables you to keep motors, engines, generators, line shafting and machines operating at efficient speeds. Price, with two rubber tips (as illustrated) $3.50. Send for free booklet no mat- ter what you want to count— automatically or by hand. The Veeder Mfg. Co., 44 Sargeant St., Hartford, Conn.

The Shipshape Home

How to Do the Odd Jobs ; TaBLes are often Restoring marred by having the varnish burned through to the wood in spots where hot dishes have carelessly been left too long. To repair the damage properly it is necessary to remove the varnish and refinish—a long, tedious, and often difficult job. Rather than go to that trouble, many a person will let the table remain as it is. There is, however, a quick and easy method for restoring such a table if it is not valuable enough to. warrant the longer process of re-varnishing. Wash the top with a strong solution of lye put on with a brush, taking care that none of it gets on the fingers. Scrape off the loosened var- nish with a piece of glass and, when dry, rub thoroughly with coarse and then smooth sandpaper. Once the surface is prepared, simply rub it with crude oil, which will give it a dull, artistic, and dur- able finish. Thereafter it will be no trou- ble to keep the top looking well.—S. R. H. Table-Tops

Where astrong brack- Bracket of et is wanted for hang- ° ing some Two Nails see object, such as a machine part, on the wall, two stout wire nails may be employed. i They aredrivenin as .-7.°*" shown, so that the

lower nail will act as + a support for the “4a pp “fs upper one. be’ This combination ¢ ~_— — makes a surprisingly the other strong and rigid sup- port, even in plaster, and may often be used, especially in places where the nails will be hidden or comparatively incon- spicuous.—H. B.

To KEEP flowers fresh, cut 14 in. off the end of the stems and plunge the freshly trimmed stalks instantly into boiling water. The petals will be seen to become smooth and resume their beauty. For keeping cut flowers in water, finely powdered charcoal, in which the stalks can be stuck at the bottom of the vase, is ex- cellent; -it preserves them surprisingly, and renders the water free from” obnoxious decomposition.—BESSIE STATLER, Keep Flowers from Fading

tein I wap a large num- Non-Splitting | per of very hard wooden ° slats to nail close to the Nails ends and the brads in- variably split the wood. Instead of waiting until I could get a small

bradawl to punch holes, I formed chisel. edges on the brads by cutting off a little of the pointed ends. This was done by plac- ing the brads over the corner of the head of a hatchet and striking the points a few sharp blows with a hammer. When these brads were driven in with their chisel points across the grain of the wood, they did not split the wood. I have used the same method on nails up to 20- penny spikes in size with equally good re-

sults.—G. M. BEERBOWER.

“Lighting Fixtures” Ready to hang. Direct from man- ufacturers. Completely wired including glass- ware. Send for Catalogue No. 24 and Dealers’ proposition ERIE FIXTURE SUPPLY CO. Desk A, Erie, Pa.

ASBESTOS We are miners and shippers of Crude Asbestos in any quantity. We produce all grades at our world famous BELL ASBESTOS MINES, in Canada. We also card fibres, spin yarns, weave cloths. and make all sorts of Asbestos products. For anything you want in Asbestos turn to

Keasbey & Mattison Company Dept. S-4, AMBLER, PENNA., U.S. A. Owners of the World’s Largest Asbestos Mines

MOTORCYCLE BARGAINS SAVE 25% to 65%, on Siahtiy used and Rebuilt Motor- cles, ide Cars, Johnson Motor heels, Evans Power Cycles, Bicycles. a aS a’ - dreds of Barpeins in used, rebui t and new machines,supplies, accessories, etc. < . AMERICAN MOTOR CYCLE CO. Dept. 715, 2047 W. Chicago Ave., CHICAGO

» eo) For trial, a sample of our New Style Copley, if you send 2 cents for postage and state size wan! Reversible Collar Co, , Dept 116 Boston, Mass,

This lathe of ai signe smal their The ' MON 9 in

It is It is big I smal You JUN shor

WHY WORK_FOR OTHERS? BE YOUR OWN BOSS IN THE AMUSEMENT BUSINESS! OUR GAMES MAKE BIG MONEY in Parks, Resorts, Beaches, Carnivals, Fairs, Arcades, Church Festivals, Picnic Grounds, anywhere people congregate for amusement. Experience unnecessary. Small capital starts you. .

Pr. 1: McAndrews did $166 first day. E. E. Rhoades took in $116 first ddy. Frank L, Moses made $51 first night. John Renner cleared $7000—Hundreds of others in all parts of the country! WHY NOT YOU? WRITE TODAY FQR CATALOGUE PENN NOVELTY CoO., Dept.B 908 Buttonwood St., Philadelphia, Pa.

COLD PIPE BENDERS Standard of the World HAND and MOTOR OPERATED 14 sizes of machines What it costs to bend pipe our way, per bend

Models E & F 1-in. Pipe, 5 cents 4-in, Pipe, 25 cents 2-in. Pipe,10 cents 6-in. Pipe. Fi conte 8-in. Pipe, $1. 00. American Pipe Bending Machine Co.

Send for catalogue 51 Pearl St. Boston, Mass.

OTT TLL LLLe LLL 1 [a et A ' <\\'

Page 95

July, 1922 It Will Pay You to Own A MONARCH JUNIOR Lathe “The Biggest Little Lathe Built’’ There are hundreds of things made of metal or wood, for the shop, automobile and home, that you can make with a MONARCH JUNIOR lathe. This sturdy dependable small engine lathe, guaranteed to do work with 1/1000 of an inch accuracy, was especially de- signed for inventors, experimenters and small shop owners who need a lathe of their own. The Greatest Achievement in Lathe Building MONARCH JUNIOR With Bench 9 in. Engine Lathe $225 Legs It is easy to learn to operate the MONARCH JUNIOR. -_ even beginners can’t jam it. It is equipped in every detail same as the big MONARCH and is guaranteed to do all small work that any other lathe will do. You can find room for a MONARCH JUNIOR practically anywhere in a small shop or work-room in your home. Write to- day for catalog and full information about this remarkable—low priced engine lathe. THE MONARCH MACHINE TOOL CO. 401 Oak Street - = - Sidney, O. 1% Same tn Ni 7 ‘ | SEND STAMPS FOR CATALOG ADVANCE DOOR LOCKING HANDLES for FORD Closed Cars . Enotatied uickiy by angone, They fit in place oF a igina han ‘ord Owners delighted Lett Phan dle locks automatically, Fight han andle Gene with key. Agents: Beau- tiful sample pair, fully guaranteed, furnished with full particulars. $: $4.50 Canada. Check. money order or C. O. D. C.B. HAVEN CO., P. 0. Box 1292 Detroit, Mich., or Windsor, Ont. “GET BUSY” MAKE SCREENS WITH DI AMON PRESSED STEEL CORNERS No mortiges, mitres, screws or tacks required. Unbreakable screen, hin es attached,made in afew minutes. Big profits ‘ing screens to order. Sample set by mail, 50c postpaid. DIAMOND HARDWAREMFG.Co. 224 FOURTH AVE., PITTSBURGH. PA, os ARD MANU see URERS NEW MOTORS =r" ALL SIZES UP TO StLP. We Specialize in Small Motorsé Generators ALL PHASES AND FREQUENCIES N STOCK AT ALL TIMES ve Mail Order Small Motor deal nthe world CHAS. H. JOHNSTON, Box EZ). West End, Pittsburgh: Pa. FOR ALL PURPOSES Largest XClUSI VIRELESS, TELEPHONE GENERATORS 500 VOLT- 100 WATT - 3400 R FOR MOUNTING MOTOR GENERATOR SETS. The A-B-C’s of Electricity (Continued from page 30) out another. The induction provides a greater range of tuning. The action of a condenser can be ex- plained without complicated terms, by again drawing upon the water analogy. Suppose we build a water tank with a hinged bottom, the latter so arranged on a simple trigger that when water has been added up to a certain definite volume, the bottom drops out suddenly, discharging the water in an avalanche. To complete the picture, it must be assumed that the trigger device automatically returns the tank bot- tom, ready for the next discharge. We have, then, the case of a water tank fed by numberless small pipes, the pipes discharg- ing their loads into the tank until the liquid has reached a certain level. At that point the tank bottom collapses and dis- charges the entire contents. Almost imme- diately the bottom is returned and the tank is filling again. The Hard-Working Condenser The condenser, as used in radio circuits, functions in a similar manner. The little electric waves come through the aerial, pass into the condenser, where they pile up, until the condenser has all it can hold. Then, like the water tank, it discharges all the stored up electrical energy instantly. Of course, it should be realized that this com- plete action takes place hundreds of thou- sands of times a second, but each time the action is identical. Before proceeding further, an under- standing of the meaning of the term “wave length” and of the manner in which radio waves are formed is essential. If two persons had at their disposal a pond of perfectly still water, of almost any length, they could arrange mechanical de- vices that would produce waves at one side and detect them at the other, just as radio waves sent out from a transmitting station are detected by a receiving set. One method of carrying out this experiment would be to arrange a’beam so that it could be dipped into the water at the will of the operator. The beam would cause water waves of different sizes to move in circles away from the sending station. At the op- posite side of the pond a light float, con- nected with a recording pencil, would move up and down as the waves reached it, thus leaving a record of their shape and relative intensity. A beam of given size, moving the same distance each time, would pro- duce waves of a certain size. The length of these waves would be measured by the distance between the tops of two adjacent waves. How Radio Waves Are Formed In radiotelephony, the waves of elec- tricity have the same general shape as water waves, but with greater lengths. They are produced by the proper combination of inductance and capacity in the sending apparatus. Inductance, as a rule, de- creases the wave length. Capacity, con- nected with inductance coils, gives the effect of increasing the wave length. Many amateurs do not consider this fact in ad- ‘| justing their transmitting sets, and as a result they fail to keep within the amateur wave length regulations of the govern- ment. They have the notion that an in- crease in capacity will increase the energy radiated by the aerial, forgetting that in (Continued on page 110) These Blades Are Renewable Neverslip Pliers are made with special high carbon crucible steel cutting blades. Should they become acci- dentally nicked or broken, they may be quickly and easily replaced with a brand new pair—just like a safety razor. It can be done in a jiffy by anyone. Neverslips will cut soft wire or insulation clean and even —no rough or ragged edges. They’re guaranteed to out- last and outcut any plier made. Just go into any hardware store and ask to see a pair of these long-lasting pliers. If your own hardware deal- er hasn’t them in stock send us his name and we'll see that you are supplied. Write for leaflet. THE NEVERSLIP WORKS New Brunswick New Jersey NEVERSLIP side cutting pliers Neverslip Pliers are furnished in six, seven and eight inch sizes If you use pliers or buy them for somebody else to use, you'll be interested in our leaf- let, “Procrastination is Wot the Only Thief of Time’. It’s mailed free upon request. Do you want a copy? } a oe ee ma ee ear eeemame cence: cern sts nee Seam me meme een

Page 96

HOMCHARGE YOUR BATTERY No mués, trouble, dirt —no moving of batteries—loss of time—no effort on your part—no tech- nical or professional knowledge needed. THE HDMCHARGER successfully meets all charging conditions, and is the only rectifier combining the follow- ing essential Homcharging features. 1. Self polarizing. Connect battery either way and it will always charge. No danger of reverse charging, ruined bat- tery or burnt out Rectifier. 2. No delicate bulbs to break or burn out. Only one moving and two wearing parts. These are replaceable as a unit after thousands of hours use, at small cost. Cannot be injured by rough handling. 3. Operation stops and con- sumption of current ceases immediately upon disconnect- ing battery. 4. The only charger costing less than $100.00 that will fully charge a battery over night. Gives battery a taper charge — exactly as recom- mended by battery manufac- turers. Guaranteed not to harm your battery even though | left connected indefinitely. 5. Highest efficiency of any three or six cell charger made. 6. Nodanger of fire. Approved by the Underwriters. Will charge any Radio “A” or “B” battery as well as your auto battery. Send for Bulletin No. 58 for further information. For sale by all radio, electrical and accessory dealers or shipped express prepaid | 8.50 for purchase price...... $20 West of the Rockies The Automatic Electrical Devices Co. 131 West Third St., Cincinnati, Ohio BRANCH OFFICES—New York—Chicago— Pittsburgh—Los Angeles—New Orleans— Detroit— Philadel- phia — Baltimore | Largest Manufacturers mi of Rectifiers in the World Popular Science Monthly The A-B-C’s of Electricity (Continued from page 109) making the addition they have probably increased their wave length. A condenser may be formed by other means than a plate of glass and sheets of tinfoil. Two wires running along the street, or two wires lying alongside each other, on the pasteboard tube of a tuning coil, are minute condensers. The aerial, lifted 40 or 50 feet above the ground, forms a condenser, with the air as the insulator and the earth’s surface as the other conductor. The aerial provides both inductance and capacity, but principally capacity. The tuning coil, with its many turns of wire wound closely in spiral form, provides also inductance and capacity, but here the pro- portion is reversed, as the inductive effect is greater than the capacity. By winding the coils in special ways, the inductance can be maintained and the capacity re- duced. A good example of this is the honey- comb, or duolateral coil. Condensers are almost perfect capacities, but a certain amount of inductance is produced by the lead wires, and in some condensers by the construction of the supports. “Direct” and ‘Alternating’ Currents Two types of electric current—direct and alternating—are well known, at least by name, to most people. All currents, when generated by rotating machinery, are alter- nating; all currents from primary batteries, such as the dry cell, and the sal ammoniac batteries, are direct. Both currents are found in radio circuits. The wave, as sent out by the transmitter, is alternating in character, and remains so until the crystal detector or the vacuum tube rectifies it toa direct current. An alternating current may be likened to the action of a stream of water in a pipe line, each end of which is connected with one end of a tight cylinder, in which a piston works back and forth at high speed. When the piston is traveling in one direction, the water is drawn from one of the pipes and forced into the other. On the next stroke, of the piston, the direction of the water is reversed. A direct current can be pictured as a pipe line connected with a centrifugal pump, the blades of which drive the water out through one line and take in the same water from the top, on its return. The action is thus continuous, and the pressure along the line unvarying. To Prevent a T-Square Rubbing a Pencil Drawing HREE or T-SQUARE Z four small, > highly polished | thumbtacks Zxzwr . placed under a KS T-square will keep it raised above a pencil drawing suffi- ciently to pre- vent the lines from becoming rubbed and soiled by the constant shift- ing of the T- square. This is also helpful when working near the thumbtacked edges of the paper.— FRANK HARAZIM. Thumbtacks raise the blade above the paper Electrical Equipment Sought, Repaired or Exchange THE FUERST-FRIEDMAN COMPANY Reliability Built In’’: CLEVELAND, OHIO Direct from Headquarters Save from 25% to 40% on standard makes of new and rebuilt motors. Get the proper size and type of motor to suit your exact needs—and get it fully guaranteed by a motor merchandising house backed with 20 years of dependable service direct to users. Write today for catalog No. 90, It quotes prices on motors of every size and type, 10c CHARGES Storage Battery At Home With an F-F BATTERY BOOSTER, which is a Full Wave Mag- netic Rectifier, with Ammeter, for 105-125 Volt 60 Cycle A.C. having Infus- ible Carbon Rectifying Brushes, which Deliver Rapi Taper Char, BatteryJust as it is inYour Car,Snap Charger Clips on Turn Switch & Battery Will be Charged in Morning.” AMMETER eliminates Guess Work. AComplete matic Charging Unit. A¥ullyChargedBattery st: ucks' 4 th xpensivell eptncomentStorage Batters it Costs toBuy Booster —— without one. Do not think yourBa‘ us fewer * = must be bought. So arges 2 to 100 volt s - Leave tteryTe - No skill am ct PortableAuto- 6 Batteries it Lifetime. - 6 charges 6 voit Battery 9¢ amps Hg 15 6 R BU Imme L Batteries O ate CETIN For GROUP Charging ask UNION UNION TOOL CHEST CO. 24 Mill St., Strong, convenient, inexpensive. A Chest for every need. ssential to men who want tools kept handy, safe, and in good condition. Sold under money-back guarantee, Write for eatalogs describing fifty styles and sizes. Rochester, N. Y, $20 Brings You an HB Charger _ Balance on long, easy terms, more than ies paid for by your big monthly profits. No —& expense for bulbs, burn-outs or ex- : pensive renewals. Sizes for 8, 10, 16, or 32 batteries. Write us for recom- mendation on outfit to make you biggest profits. HB users clear $150 to monthly—you can, too! Write today, HOBART BROS. CO. Box P7 Troy, Ohio The Midget subtract, multiply and divi bination ‘of whole numbers **Five-in-One’’ Slide Rule ee combination Manabels. Poveet tract Sifde Wale it will ioctently 2a, je any com- Hf) mixed numbers and decimals. Gives Gilson Slide Rule Co., Niles, Mich OVER $200 PROFIT Weekly Above Expenses ) methods and equipment. VULCANIZER CO. All over the U.S. and Canada, we are establishing vulcanizing , service stations. We instruct you and furnish the most modern THE ANDERSON Known the World Over. We have 34 schools in U. S. and 4in Canada. One is near you. School pays you $5 per day while learning to operate the station which you start in your town or elsewhere on small capital. Write for full particulars TODAY. THE ANDERSON STEAM Manufacturers 0; Modern Tire Repair tpmen } 201 Williams Bidg. Indianapolis, U.S.A. July,

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—— , 'f | KOR tam | tt ae he eset eiees Soe eeecgece t dad | Bat 9-4 > EEE rte ~a July, 1922 THE HOME WORKSHOP How to Take Unusual Pictures with a Cheap Camera By J. F. Yocum MANy amateur photographers think that they cannot take unusual and striking pictures unless they have a costly camera with a fine lens and shutter. That is a mistake, because the ordinary camera will register in black and white on the sen- sitive films of today as much and more than the eye can see. It is mainly a matter of making the proper exposure. The accompanying photographs were taken with a postcard-size folding camera A snap and a time exposure on one film achieved this effect that has no special attachments of any kind. They show that good pictures can be obtained even under adverse conditions. In taking the sunset view, the camera was placed on the tripod about fifteen minutes before sunset, and _ pointed by means of the finder directly at the sun. The distance was set at 100 ft., time 1/100th second, diaphragm F-16. Just as the sun touched the horizon, the bulb was pressed. That gave sufficient exposure for recording the sun and its reflection on the water. The camera, film, and diaphragm were left in the same position until the sun went down and then a time exposure of 5 seconds was given, registering the clouds, sun, and hills on the same film. The above view is looking toward San Pedro from the pier at Long Beach, Calif. To make the portrait of myself, I set the camera carefully at the distance measured to the chair where I was to sit, and set the bulb for time, with the dia- phragm closed to the smallest opening. The bulb was press- ed, starting a slow exposure; I quickly seated myself and re- mained still for four minutes; then I got up and stopped the exposure by pressing the bulb again. The Picture was taken in a darkened room with only one small north window open. The picture of lightning was taken on a dark night in northern Illinois. The camera was set pointing ahead of a thunder- storm that was passing some distance away: The diaphragm was given its largest open- ing and the bulb set at time and pressed. This can be done on a dark night and the film left for a period of five minutes before it is materially harmed by the exposure. If, (Continued on page 112) A self portrait taken without attachments Starrett and — Mechanics who know Starrett Tools prefer them for their superior quality, more efficient desigt, greater durability and dependable precision. When they buy Starrett Tools they know they’re getting value for ev: Illustrations and complete the entire Starrett line of fine tools are given in the Starrett Catalog No. 22W and special Supplement of new tools. Copies free on penny spent, escriptions o Starrett .Auto mechanics have been looking . oe T-Handl - e Tap Thickness Gage No.71 THE L. 8. STARRETT CO. Wrench No.93 Contains six leaves ci mg be 4 o Wed A ly hand particularlyadapted ATHOL, MASS, coat dor bebdin id — ay = ——. cally all taal tools to e turne vy an for aging slots. The New clamp construc. rely sa eaves have, re- oa yee gtipon peso thickness ouuumias Fw tin . of .0015, .002, .003, .004, 006 and .015. = Miles Per Hour! mm (srecord of our stock ‘\ car, using our special 1922 motor. Anybody can assem- ble this car. Send 30 m@ cents for plans, in- structions and price list of parts. SYPHER MFG. CO., 174 Syphor Bidg., Toledo, Ohie HAIR GROWS When nourished NA- TURE’S WAY. No Ton- ics, Salves, Drugs or Electricity. Wesend our Vacuum Cap on 60 days FREE TRIAL to people who show that they are willing and able to pay if satisfactory. ten minutes daily. Try it 60 days at our expense, Booklet on Hair and its growth mailed free Sealed MODERN VACUUM CAP CoO., 400 Barclay Blk. DENVER, COLO. Be first to write quick for 5s — Agents Offer and Low Wholesale pa ay ange TIRE & RUBBER co. Mellinger Extra-Ply and Cord Tires. Make big money part or full time. No capitalor experience Sections Furnished. GUARANTE needed. Sam - 000 Miles materials. TIRE $ SanVSon CAR to one user ineachlocality. 2 North Oak St. Kansas City, Mo. buying The Cen Speedster 1. -F. upholsteri ring, me metal ¥ Flat radiator shell tyy aie wind resistance. Price Only $45.00 For This Job Complete Save exorbitant freight rates and one-half or Not Paper Patterns ny one Parts Comp! All lete this job. “Complete with hood, radiator s shell, instrument parts, wood parts, bolt screws, etc. 0 Designed low with lack of © set up $9C. Furtn ther particulars on request. tral Auto Supply Co. Eng. Dept. 122 Louisville, Ky. How to Run a Lathe 9” x3’ Lathe 11’ x4’ Lathe 13” x5’ Lathe 15’ x6’ Lathe 228.00 304.00 376.00 REDUCED PRICES Back to Normalcy—20Y% Further Reduction SOUTH BEND LATHES-—EST. 1906 Change Gear Chateed oe Gear $176.00 $216.00 Chanee Geer Change Gear 16"x 8 Lathe $452.00 $512.00 273.00 | 18°10’ Lathe 656.00 soo | zirziz’ Lathe $48.00 923.00 431.00 | 24”x14’ Lathe 1140.00 1230.00 Free Catalog No. 67 SOUTH BEND LATHE WORKS, 433 E. Madison St., SOUTH BEND, IND.

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One of | theBoss’s Habits é He acquired it when he was an apprentice— then he used good tools because the older men told him to. Later he learned from his own experience that good tools helped him. He knows the value of good tools. A Y” He Uses— BROWN & S! TOOLS He will tell you that they helped him advance. Their high accuracy, clean cut graduations, correct design and construction, first class material, and skilled workmanship show in the better results in the work of the man who is using them. Catalog No. 28, showing over 2000 of these tools, on request. BROWN & SHARPE MFG. CO., Providence, R. I., U. S. A. Established in 1833 Popular Science Monthly. IVER JOHNSON A 20-minute walk a 5-minute ride What a convenience is an Iver Johnson } bicycle! Sleep a few more minutes in the morning—take a little more time at breakfast -—then hop on your bicycle for a bracing ride to the Station. No more missing the train. And at night, instead of a tiresome walk home from the station, another short ride to put you just right for a good dinner. The truss-bridge frame, seamless tubing of nickel steel, drop-forged parts, two-piece crank set—these are some of the features that guarantee the strength, speed, and durability of every Iver Johnson bicycle. The oldest firm in America making bicycles continuously. Write at once for free Bicycle catalog ‘‘B5.” Firearms catalog ‘‘A5’ also sent on request. IVER JOHNSON’S ARMS & CYCLE WORKS, 5 River Street, Fitchburg, Mass. New York Office: 99 Chambers St. San Francisco Office: 717 Market St. Keep anIver Johnson “7 revolver in the home Ask your dealer to show r self-protection, youan] 2 Neco Nira pion single barrel shotgun, ”? ecurate, dependable, Quick, accurate, moderately priced. safe. THE HOME WORKSHOP How to Take Unusual Pictures (Continued from page 111) however, some small flashes of lightning occur, a new section of film will have to be turned up. When the big flash comes, close the shutter immediately. Nineteen seconds were counted from the time the flash was seen until the thunder was heard. As sound travels 1100 feet a second, the flash proved to have been nearly |. four miles away. In one lightning picture I was puzzled by |" a sort of ball of light, as if a flash had been snarled up. Enlargement of the spot ————— This lightning flash timed itself shewed that it was really the projection of a crooked streak coming from a distance to join the main streak, which was closer to the camera. To obtain the photograph of the pacing race, the camera was set to point at a cer- tain pole and when the leading pacer’s nose came in line with the pole, the camera was snapped at 1/100th second and F-8. It will be noticed that this view brings out the well known fact that there is an instant in a |) pacer’s gait when all four feet are off the } The leading pacer has four feet off the groun ground. The leading pacer is in that posi- tion in perfect form; the second horse has two down and two up, also in perfect form, but at another phase of a pacer’s gait. Good pictures can be taken from the win- | dow of a fast train or the observation plat- | form, but do not attempt to take a picture | looking forward because cinders or flying } sand are apt to ruin your camera’s lens. WHEN grinding, a pan of water on the | cross slide and under the wheel will catch sparks and dust.—J. T. ART COLOR PRINTING CO., NEW YORK ~