Popular Mechanics 1930-08: Vol 54 Iss 2

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25 CENTS ENE’ POPULAR |- MECHANICS MAGAZI V) WRITTEN SO YOU CAN UNDERS $ ~, : ui? j fy a hes bs s ¥. at > “ > r » ’ * at \ 4. ke § . 7 ad

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opular Mechanics Magazine 200 E. Ontario Street, Chicago, U.S. A. H. H. WINDSOR, Founder H. H. WINDSOR, Jr., London: Hachette & Cie., Paris: Hachette & Cie., Belle Sauvage, Ludgate Hill, W.C. 2 111 Rue Reaumur Editor and Publisher Melbourne: Gordon & Gotch 09-513 Little Collins Se. SUBSCRIPTION: ISSUED MONTHLY SINGLE COPY, 25 CENTS ae In United States and its possessions, Canada, Cuba, Mexico, and all | $2.50 countries in the Pan-American Postal Union, per year, postpaid ) =: To all other countries in the Postal Union - - - - - - - - - - 3.00 : All subscriptions are discontinued at expiration. Please examine the date printed on your wrapper. Entered as Second Class Matter Sept. 15, 1903, at the Post Office at Chicago, Illinois, under Act of March 3rd, 1879. Entered as Second Class Matter at the nthly by POPULAR MECHANICS CoO, Post Office Department, Canada. Copyright, 1930, by Popular Mechanics Co, Copyright in Australia. Copyright in France Contents for August, 1930 No. 2 ~~ Special Features Is There a Perfect Crime? This Inventing World Are Things as Good as They ‘Used to Be? At the Bottom of the World with Byrd Midget Cars Next ? Why People Are Superstitious The Wizards of Schenectady A Bigger Voice for Radio - . 194 een ) 202 Fike 214 225 aia | .. 243 heewees nant 250 pres 266 NE J 1s 2 fodel 3 ng—slogans written in water on sidewalks Busses—equipped with radio to entertain passengers ered— s Cap—soldier’s, marks entrance to military camp 220 detail; ached to auto aids in training pilots 208 Cats—clambering up building attract passers-by 263 od the ve, gives all the thrills of flying 283 Chairs — it electric model flies and lands itself 252 rigid, are nested to economize space 221 ° expands to fit load 272 single-wheeled African taxi run by man power 241 211 pleased fly without leaving ground in compressed-air plane 288 Children 7 1 do not tale vapor of, turned into water 241 doughnut eating contest for young riders 255 en woe kiddie car for use in water 285 chai nerstone” of huge airship raised into place 224 Clock mail bag from speeding train 42 talking, speaks time on hour and half hour 209 thank you > 1 , . delighted S.—looking down on Uncle Sam’s latest wound but once a year keeps perfect time 290 sure from er 273 Crocodiles—over thousand, carried by two trains 193 ( swinging door for, keeps dust inside 275 Cutter—motor-driven makes letters with beveled edges 245 t y Dam—stops loss of land 271 labe tells time of day and position from sun . 249 Dogs—fed on cheaper meats have better health 264 Bertha” brings stars nearer 222 Doormat—moving brushes of, clean it automatically. 255 le—Racer—eyeshield for, replaces goggles 263 Electric Wiring—laying wiring under canal tests en- e tha les gineers’ skill 275 able ty g car carries lion cub as extra passenger 248 Electrical Appliances—window washer cleans and dries 289 dl quality shown by spring tester 256 Engine—small gas, operates model plane or boat 22 —_ e es—Accessories—knotless towrope easily at- Fence—sheet-steel road, is safer for autoists 265 suct i 289 Fire Extinguisher—tube-form, for home and auto 256 a it es—Driving Fish and Fishing omeee" tards speed of autos 273 artificial angleworm bait comes by yard 257 oupon ireless drivers with lines of lights ........ 283 electric lights over water lure food for fish 263 : 1 won't feel the bumps 276 rubber waders for anglers worn like trousers 295 va | — 7... pe with stop watch helps catch speeders 288 sanitarium for goldfish 209 a deposit # “Aut es—Painting—rotary paint striper rolls lines spearing swordfish from a swinging “‘pulpit”’ 200 send you 8 . 249 ten thousand miles sailed for a fish 246 aid; i A s—Repairing—first-aid car for motorists... 272 Food a ver the hell stretch 259 glass-packed meals come ready to serve 209 five your si th glider wings gives thrill of flying 247 quick freezing promises to lower cost of 212 beautiful, saved from extinction by law.. 210 Fur—spring-wire stretc hers replace wooden frames 219 Boating—portable boat carried in car in- Garage—the car's weight opens and shuts doors 193 - ' exhaust 220 Gardens—seagoing, supply flowers on liners 223 . less bands for, reduce shipping costs 219 Gas Mantles—are radioactive 253 : : kers’ aerial shop suspended from crane 253 Gasoline Filling Station—roller skates speed work at 290 } r—run by tractor clears new land 223 Glider—with sails depends on wind for power 284 1uge office structures run like a small city. 281 Golf—electric auto as caddy serves crippled player 199 {Continued on Page 4]

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[4] [Contents—Continued] Gun—big machine, most deadly weapon ever made 281 Gymnasium—children’s gymnastic school in Berlin fitted with mirrors 224 Household Devices 286 Lamp—of three colors guards rail workers 254 Lifeboat—for seaplane has sail and motor 254 Life Saving—life guards use seaplane in rescue work. 219 Mines and Mining—dipping needle compass finds iron- ore deposits 289 Metal—alloy light as aluminum and hard as steel... 289 Motor—carried on back runs tools . 242 Moving Pictures block-letter movie titles produce novel effects 265 made of yourself while you wait 274 Music—animals depict music notes to teach children. 281 Newspapers—baler for old, simplifies tying 257 Ocean—craft to travel bottom of, utilizes rubber shields 220 Paints and Painting—multi-color airbrush paints three shades at once 257 Photography—hide-and-seck tent is used to . birds ° Pipe Line—radio aids in laying i” Poison Ivy—easy to cure 294 Poultry—automatic feeder operated by clock 280 Radiator—heat chamber in, keeps dishes warm 271 Radio helpful hints from the laboratory 300 tinfoil fuse protects meter 302 Radio—Aerials—bringing in the antenna lead 296 Radio—Applications . movies on steel tape 280 radio locates water pipes without digging 210 ultra-short radio waves guide ships in fog 241 Radio—Installation—concealed for auto easily installed 295 Radio Loud Speakers boosting the volume of magnetic speakers 303 talking back to the 297 Radio Receivers—kit makes automobile receiver 299 Radio Reception humless, electric radio-tube improves 274 trouble hunter in car ends interference 247 Radio—Repairing broken sockets in power packs 299 checking service voltmeters 304 Radio Television method of suppressing interference caused by flashing signs 302 photo-electric cell of rugged construction 299 shielding of neon-tube leads improves pick-up 298 Radio Transformer—high line voltages reduced for standard a.c. sets 299 Radio Tubes laboratory voltmeter employs tube 298 power tubes operate in series from five-volt tap 296 Railroad—flying redcap takes baggage on aerial railway 209 Science energy of workers is measured by treadmill 201 glaciers’ speed told by metal shells buried in ice 224 Ships and Shipping balancing the propellers of ocean giants 246 ship’s tragic end shown in unusual photo 199 Sled—two-wheeled motor pulls sled through snow 283 Smoker’s Accessories—sanitary ash-tray receiver 253 Snowplow—rotary attached to front of truck 285 Steel—cleaner keeps steel tape from becoming rusty 207 Stencil Tracing—is made easy by frame 248 Tanks—sha like balloons for greater strength 213 Telephone Directories old, turned into roofing paper ........ 263 index letters save time for user 273 Tennis—press for racket exerts even pressure 221 Tool Box—bench and ladder contained in suitcase 223 Tools hydraulic drives for 295 nipple and coupling wrench reaches hidden fittings i. Tractor—queer, does work of six horses Truck—with flexible floor unloads automatically 31 Tunnel—strangest, to join Europe and Africa 211 Vacuum Cleaner—for streets 213 Valves—new way to reseat 249 Wallpaper aluminum coated 272 electric paster fits roll for hanging 264 Warfare—navy battle in show window is run by clock 282 Water Pipes—test plug for, helps in backfilling Weather—fiying weatherman gathers data from air- plane 193 World’ s spattered hooks’”’ to medion roofs of, build- ing . 201 AMATEUR MECHANICS Airplane—compressed air is power for 8-foot plane Archery—sport with a cross-bow Automobiles—extended starter button Automobiles—Accessoi'vs—cushion for driver Cabbage—tar-paper shields foil maggots Camping preheating camp stoves salt shaker for the camper Cistern—keeping dirty rain water out of Clothesline holders for the basement weight keeps taut Curtains—drying and stretching sh Desk Tray—mailing tube makes good Electric Wiring—quick change from series to parallel : Faucet—easy way to grind in faucet seats Fish and Fishing—submarine lantern attracts fish Food Grinder—bag on catches crumbs Footstool—upholstered, simple to make Garage—doors opened from car Gardening—old pipe distributes seed ag: ~*~ epaneemel used to exterminate grass- hopp: Sieenabaient-geupdis two canoes Paints and Painting—atomizer for spray painting Ship Models—oars for Sink—coil spring removes obstruction in trap Stairway—use of space under Target aerate mesa makes expert marks- men : Toys how to build that cycle car man rolls uphill Umbrella—shelter made from large Walls—baseboard blocks save bedroom Windows cut-outs make shutters attractive scaffold supports from angle iron for washing

STRO Builde Throu have t streng physic. the be physic. STRON other sy SHOP NOTES Automobiles—Lubrication—aids to lubrication of Ford 3 Automobiles—Repairing—balls in brake drums cause ce Ball-Bearing—changing, fit 348 and. ste Chuck—U niversal—truing work in worn 346 Drafting—ledge on the T-square Drawings—transparent lacquer used to protect Garage—waste holder for the Gauge—push-in handle, for snap Gear—repair for rawhide Hoisting—expert tells how to ‘sling loads for safety : wonderf, Ladder—extension leg for 339 was ev Lamp—star, adds beauty to home “Promot Lathes—crowning large pulleys in a small 346 il Logs—“‘petrified”” made of concrete 352 FREE. “\ Measuring—screw threads 338 ? Milling—an accurate keyway . Paints and Painting brown stain for mahogany use old brushes for painting concrete Pigs—protecting suckling q Scraper—hardening edges Screws—pipe nipple aids in starting wood Steel coloring for layout drilling hardened ls ly

m Your bo< k and Men adjustable gasket cutter Bin which | for cutting strips simple brace for speedy driving of screweyes Tractor—keeping water can on Trees—spraying tall Truck—transports boxes horizontally Vise—improved woodworkers’ Windmill—old, pumps new well Window Display—lawnmower for store Workbench hinged miter box can be swung out of way portable saves mechanic’s time Workshop handy soapstone holder starting small brads tool racks for the traveling chair aids workmen

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STRONGFORTISM Creates New Energy & Strength Through STRONGFORTISM men all over the world have been rejuvenated and restored to health and strength after they have suffered untold mental and physical horrors as the inevitable result of neglecting the body, excesses, fast living, and abuse of their physical power. STRONGFORTISM has a record unparalleled—there is no other system, or method, or course that compares with it in impaired human beings to health and strength. STRONGFORTISM begins at the source to create new energy and strength by utilizing Nature’s forces scientifically. It builds up the internal muscular system first, increasing your External muscular development follows ad you become a new man inside and out—a fellow to be reckoned with and envied wherever you go. I Want to Send You MY FREE BOOK This book of many pages and dozens of pictures tells of my experience—and then how STRONGFORTISM Strongfort ease send me absolutely free my copy of shun you. It’s You can Institute, Dept. 60 ..Lung Troubles . Round Shoulders . Stomach Disorders . Increased Height . -Muscular Development .- Great Strength POPULAR MECHANICS ADVERTISING SECTION GANGWAY I for Strong Men" Weaklings Stand Aside Be defiant, courageous, MANLY! You won't be regarded as a real man if you are a slouching, nervous, “Dont tell me you never had a chance! “Four years ago you and I worked at the same bench, I realized that to get ahead I needed spe- cial training, and decided to let the International Correspondence Schools help me. I wanted you to do the same, but you said, ‘Aw, forget it!’ You had the same chance I had, but you turned it down. No, Jim, you can’t expect more money until you’ve trained yourself to handle bigger work.” There are lots of “Jims” in the world—in stores, fact. ories, offices, everywhere. Are you one of them? Wake up! Every time you see an I. C. S. coupon your chance is staring you in the face. Don’t turn it down. Right now over 180,000 men and women are preparing them- selves for bigger jobs and better pay through I. C. S. courses. You can join them and get in line for promotion. Mark and mail this coupon, and find out how. aaa eae a ee aaa aero cree eel eel INTERNATIONAL CORRESPONDENCE SCHOOLS “The Universal University’ Box 5694-F, Scranton, Penna. Without cost or obligation, please send me a copy « of your bo me let. “Who Wins and Why,.”’ and full particulars about the subj: before which I have marked X: TECHNICAL AND INDUSTRIAL COURSES CD) Architect Automobile Mechar le | }) Architectural Draftsman Plumbing Ste » Fitt [) Building Estimating Heating ] Ventilation }Wood Millworking }Sheet Metal Worker Contractor and Builder [| } Structural Draftsman } Structural Engineer Electric Wiring Electrical Engineer Electric Lighting Steam Engineer }Steam Electric Engineer ic ivil Engineer }Surveying and Mapping ] Refrigeration (1 Highway Engineer }R. R. Locomotives Welding, Electric and Gas |R. R. 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WORLD'S AIRPLANE RECORD® 43,166 FT. MADE BY LIEUT. APOLLO SOUCEK JUNE 4 1830 —~™ 89 DEGREES BELOW ZERO, FAHRENHEIT —— ices _ 41,794 FT. MADE BY WILLIE NEUENHOFEN IN GERMANY MAY 25 1929 S MT.M¢ KINLEY __ 20,300FT)” - 5% UNOFFICIAL BALLOON RECORD 42,470 FT. MADE BY CAPT. HAWTHORNE C.GRAY Me ap eer Sok eh tet “ MT. EVEREST ~~ *>29,002 FT. OT YET CONQUEF Heights of Record Airplane Flights Compared with Altitudes of Famous Mountains and Skyscraper; in ‘ Lieut. Apollo Soucek Wearing Special Mask, Heated Goggles and Clothing for Sub-Zero Weathe

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Popular Mechanics Magazine REGISTERED IN U. S. PATENT OFFICE WRITTEN SO YOU CAN UNDERSTAND IT 1. 54 AUGUST, 1930 No. 2 R. D. Kell, Operating Television Theater Projector, Showing How the Picture Is Projected from Back- stage; beside the Screen Are Loud Speakers for Reproducing Accompanying Radio V A DARKENED theater, & curtain pulled and puff vigorously. A cloud of smo! ** back to reveal a screen, six feet high filled the upper half of the screen seven feet long—forty-two square As the master of ceremonies, i of silverv wall—and the world’s first then introduced several vaudeville t x television show ina regular theater and soloists. The team partners Tl. vere se] irated bv the dist ince betwe he projection apparatus was behind _ the theater and the improvised laborato reen and, not in the rear of the studio. Yet they enjoved an ter as with the movies. On the left neous exchange of thoughts, so that yf the stage, a green spotlight shed was possible for them to g hostly glow over an announcer stand- nouslyv, as if both stood on the stage be beside a microphone. Then out of tore the audience. lark boomed a voice: The significance of television that you, Trainer?” realm of entertainment became ere we are! clearer, when an orchestral leader, ] ll Trainer’s moon face, wearing a Gamble, gave the title of four sel in, double its actual size, flashed to his musicians in the orchestra pit \1 creen. lifting his baton, they ] é see some smoke.” commanded first chord of music. From the distat re announcer. “Light a cigaret!” laboratory, Gamble conducted 1 ! er, who was more than a mile with no more difficultv than if | listening through a telephone, al- been in the theater The crucial te his voice came back to us loud his conducting and the iter, was seen to light a cigar | Fat Nilele o be heard all over the 2,500- Dr. | F. W Alexander eS TED AN ll RE A - SS) ae, - Sei ie ; a “ss pice 1 1 , et came when the orchestra pla ta cu

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POPULAR MECHANICS they were entertaine 7 talevieton signet? Voice signet A | by wavelengths and lenses. What the show man calls “emotive forc: came out into the theat« Are laght Those who sat before t! P Voice receiver ‘4 television screen wei ‘Tetevision , ‘ moved by the symbols « recetver - “) laughter and pathos. Brought to the final audience and spectator were escorted backstag The television project: Arm plifter is a vivid are light ae SeENAIee tobe" Sram closed in metal. As comes out of the illu nating chamber, beam of light is cor densed to a pencil’s dia) eter. It passes throu a tinv aperture in t diaphragm, then throu Oscillator ( television) a water cell. Now yg aoe tee car reaches the vital sta in the Alexanderson tem of television. At coming out of the wat cell and polarizi: prisms, the beam me a wonderful device vented by Dr. Aug Karolus, of Leipzig, G -~900 wett arc | Microphone amplifier Te voice tranemitter Projector Lens System Polariging prisms— (— many—popularly cal! Condensing iens—— |\ | a “light valve.” Diaphragm - , x The Karolus pre | moment makes life-size televis Diaphragm « Condensing ©, possible. It has the ity to turn an int beam of light on and at high speed. Anot explanation describ« cell as a flask filled nitrobenzol, which ally twists a_ bean Courtesy General Electric Co. Top to Bottom, Complete Receiving Layout; Complete Transmitting Appa- light. In the Alexa ratus, and Detail of the Receiving Layout son system the Ka: song. Gamble alternated with the drum- valve displaces the neon tube, use mer and pianist in blowing out notes such other systems of television. Its rol as cuckoos sing. television is similar to the loud spea! Save for one slight interruption, the pro- _in radio receiving. gram continued for overan hour. The audi- The subject to be “televized” stan: ence heard and saw mezzosopranos, come-_ fore a rectangular opening, each sid dians, monologists, as wellas Gamble and which has a photo-electric cell. O1 Trainer. Everybody lost interest in the outside of the studio wall stands a | mechanics of television; the realism was legged apparatus supporting a scam convincing enough to make them forget disk, about the size of a bicycle wh:

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POPULAR ynchronized motor and an are light in- cased in metal. This scanning disk, un- like the one at the theater, does not con- tain lenses in its forty-eight apertures. [he openings are just plain holes and the disk rotates at a speed which allows 40,000 apertures to pass before the lamp beam in one minute. From where he stands, the subject sees i flickering light coming through a two- inch aperture. At the illumination falling on the very dim. In fact, he is plunged into almost complete darkness. most, subject is But since no actor likes to per- form under such conditions, Doctor Alex- nderson was faced by a real problem un- til he devised a method of illuminating the iny studio, the use of dull blue incan- descent lamps making it possible to in- crease the illumination. Since blue neu- tralizes the orange gelatin covering the ‘hoto cells, the vital pulsations suffer no nterference. Several broadcasters are now sending ut television signals, and they are being ceived hundreds of miles away. But hey are merely silhouettes a few inches gh. Attempts to broadcast halftone iges over long distances are still unsuc- ssful, according to Doctor Alexander- m. It is dificult enough to send a tele- ion “still,” but if moving figures are at- npted, the reception is blurred. With- ut making absolute predictions, he does, vever, hold forth hope. Che General Electric constant laboratories are communication with the irt-wave station VK2ME, at Sydney, ustralia. Recently, a world’s record for levision reception was established when Schenectady short-wave station trans- MECH ANICS tha sh Demonstrating Automatic Baking Machine That Cooks hree Pancakes a Minute AUTOMATIC FLAPJACK COOKER BAKES THREE A MINUTE Turning out flapjacks or hot cakes at the rate of three a minute, an automatic pancake-baking machine does everything but serve the The b griddle huge hourglass, pours out the batter, bakes one side and turns the cake to complete the baking. It is intended for use particularly in rest rants and hotels. finished product. shaped like a in, au- BIG WAX MODEL OF HUMAN EAR IN HYGIENE MUSEUM One of the interesting exhibits in the tted a black rectangular design on a recently opened German hygiene museum hite postcard. in Dresden is Imost instan- | a huge model eously, the | of the human ign was re- | ear made of vadcast by wax. The K2ME ona model shows elength of meters and eived in enectady, complete uit requir- ibout one- every organ in- volved in the ense of easv to under stand how th second. Model of H uman Ear Compared with Size of Man's Head sound Waves reach the brain.

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POPULAR Wood Caricatures of Paul Whiteman and George Ber- nard Shaw Show Novel Technique of Austrian Artist CARICATURES IN WOOD SHOW SKILL OF ARTIST Caricatures of famous persons are pre- sented in wood by a craftsman in Vienna, Austria, who carves and paints his figures in a distinctive manner. The accompany- ing busts of George Bernard Shaw and Paul Whiteman illustrate the character of his work. JARS OF WALKING ARE GUIDE TO AUTO COMFORT Automotive engineers have found that a rate of vibration of about ninety a min- ute, the same as the num- MECHANICS periodicity of the vibrations can be changed by adding a weight to the han- dle or by lengthening or shortening the projecting part of the instrument. This shows why a car with longer wheelbase will have a less angular deflection when passing over a given bump. In the usual car with semielliptic springs, those at the front are usually much stiffer than those at the rear, because flexible front springs would make steering more difficult, and the rear springing is more important than the front because the passengers usually occupy the rear half of the car. The disadvantage of this is that a car so adjusted usually pivots at a point well toward the dash or even ahead of it, thus causing greater bounce in the rear seat Properly adjusted shock absorbers, whic! should act as dampers without interfering with the flexibility of the springs, can b: installed to counteract much of the un pleasant bounce in the back seat. STAIRWAY IN LINER’S FUNNEL LEADS TO LOOKOUT While modern motor-driven liners do not require funnels, smokestacks are still built into the vessels because it has bee: found that passengers expect them. On oil and coal-burning ships, “dummy stacks are sometimes used to serve other purposes. One funnel on the S. S. “La fayette,” new transatlantic liner, has a plat ber of steps a man takes in the same time while walking at normal strides three miles an hour, is the most comfortable for the springing system of the average car. A slower rate may produce a feel- ing of seasickness, while faster action seems harsh. Many factors en- ter into the spring adjust- ments, but some of the chief principles involved are apparent in flipping a common table knife when the blade is held firmly, flat on the table, and the handle bent “oss. —————= down and released. The Looking Down on Funnel of S. S. “Lafayette, ” Fitted for Observation RC

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m inside it a few feet the top and an in- stairway leading to funnel mouth, where sengers gain a view the vessel and = sur- inding sea. Several ntilator openings also located in the top of big smokestack as ll as a siren which can used for sounding rning signals. USEFUL CHEMICALS FROM WATER IN OIL WELLS Salt-water waste that eretotore has _ inter- ed with oil drilling op- tions and polluted is being sal- reams ’ iced for the valuable Fighting a Riot with the Armored Tank That Shoots Powerful Streams of emicals it contains at ne of the Oklahoma fields. Sodium, cal- im and magnesium chlorides are among chemicals obtained, the treatment and lamation processes being simple and xpensive. From a barrel of salt water than 100 pounds of solids are ex- ted, much of it iodine. ROLLER SHARPENER FOR RAZORS FITS ALL BLADES Safety-razor blades of all kinds as W ell as old- stvle blades are riven keen edges in a sharpener with metal balls between which the blade is slipped and drawn back and forth to pro- an effective edge. The unit occu- but little space, is always ready for e and requires no skill to operate. CVatent papers today simply bear a fac- signature of the commissioner of but, early in the last century, ne was individually signed by both esident and the secretary of state. POPULAR MECHANICS Water Instead of Bullets ANTI-RIOT CAR SHOOTS WATER FROM ARMORED TANK Berlin’s police department has been equipped with a number of anti-riot auto- mobiles to dispel unruly crowds. The car is an armored water tank on wheels capable of shooting water at tremendous pressure. Each car has a capacity of fiftv-six gallons and the turret, resembling that on war tanks, is so arranged that water can be thrown in any direction. BOTTLE CAPPER ALSO SERVES AS CONTAINER OPENER Sealing bottles perfectly with a simple downward motion of a lever, a small and compact bottle capper now i available that is extremely simple to operate. \ cap is inserted at ‘ the top and the lever is pressed down to seal standard bottles of any size or height. It is claimed not to break bottle tops and, as an added convenience, the lever can be used as a bottle opener.

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182 POPULAR MECHANICS PLANE HITCHED TO DIRIGIBLE BY HOOK IN FLIGHT Navy Biplane Connecting with the “Los Angeles” in Flight Mooring an airplane to a dirigible while both craft are in flight again successfully ac- complished recently when a navy biplane was hitched to the “Los An- geles,” flying over Lake- hurst. The airship is equipped with an adjust- able hook or was mooring bar on a hinged steel frame which is from the underside of! the big bag. Pilots of the plane have to exerci great care in making thx contact, for a false ma neuver would result in serious damage to the plane or its propeller, or to the dirigible. lowered HEAT RADIATED BY EARTH NEW WEATHER GAUGE What the weather is likely to be may be accurately told a year in advance through measuring the amount of heat radiated by the earth, a scientific feat now being accomplished for the first time in history. For many years, it has been possible to gauge the amount of heat radiated by the sun, but the other factor, one considered highly important as affecting weather changes—the amount of heat that the earth sends back—has been largely a mat- ter of guesswork. In this latest activity of science, the airplane is playing an im- portant part, as it has in other fields of research. On cloudy days, army pilots take off from Bolling field, under the pervision of meteorologists from weather bureau, with an instrument tached to the side of the cockpit of planes. It is a photometer, so adju that it records a comparison of reflect between the sky illumination and ground reflection. Cloudy days are ch for the work because, under such co: tions, the radiation from the sun is 1 nearly excluded and it is possible to termine more accurately the amount heat being given off by the earth. airplane permits these measurement different altitudes and over a wide Another instrument being used for radiation research is one that mea the amount of heat given off by the « ;

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POPULAR night when it is cooling off. ientists believe that when they an index as to the amount radiation from the earth, they ll be able more accurately to ite turbulent centers that give e to storms and other weather nditions. FLOWERPOTS ARE USED TO PRODUCE MUSIC Musical flowerpots featured an hibit of odd instruments made Chicago school children re- ntly. Hung upside down by res from a rack, the pots, of erent sizes and different thick- es, produced melodious notes hen tapped with padded ham- i rs. Among the other articles : played were chimes le from brass tubing cut into erent lengths, a drum and bourine prepared from sheep-, Chinese n stretched over cheese boxes, Egyptian harp made of half a tal cartwheel mounted on a oden sounding box, and a Nu- in sistrum, contrived from a nger and metal washers. coat

Sand-and-Cement

t 4 , . nt yr Chicago Daily News é i a Tune on Flowerpots; One of the Unusual sical Instruments Made by School Children

MECHANICS 183 Model of Cathedral Which Contains Chimes Operated by a Keyboard Small FIVE-FOOT CATHEDRAL MODEL OF CEMENT AND SAND Constructed entirely of cement mixed with sand, a model of a cathedral, five feet and ten inches high and eight feet long, has been made by a student university in England. contains a peal of five bells which can be chimed by means of a keyboard, and other tower holds a clock that runs. Or: front is patterned aiter a cathedral in England. DEMAND FOR COWBOY BOOTS KEEPS FIRM BUSY From 15.000 to 18,000 pairs of COW DO manufactured annually by a Kansas firm that keeps forty persons busy boot S are supplying the demand to cowboys, “dude ranchers, stockmen and some _ farmet who prefer this style of footwear. <A few are sold to circuses, rodeos and ot! exhibitions. Some patron orate boots and for them a special erade costing $85 a pair, is provided.

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By BUD PERL Note—The writer of this article, though only sixteen years old, is the holder of a glider pilot’s license which he won with less than six months’ training. wa I started to learn how to fly a glider, the instructors put me at what they called “ground work.” In this I learned how a primary glider is put together, what each part is made of, and why it stays up in the air. Then I was placed in the little seat of this elementary airship and taught to run it on the ground. Afterward, I flew a sailplane and ob- tained my license as a pilot. As I look down from the cockpit of a sailplane, soaring 200 feet or more above the earth, I remember with a laugh the doubts which filled my mind the first time I sat in that training glider and grasped the stick in my hand. The pri- mary training glider is far from the beau- tiful thing the sailplane is, for it con- sists mainly of a steel skeleton to which wings are fastened, and having out in 184 Fly front a shallow seat f the pupil. The rudd controls for the feet the stick are the sar and in the same relat positions, while the | altitude to which tl glider is allowed to 1 takes all danger out the first and most portant part of traini I took my seat in t “All Ready,”’ Shouts Bud Perl from Cockpit of Perl Directing Wing Assemt

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chair out in front of the gy, put there for the express rpose of overcoming what- fear may be in the mind the pupil, and of giving him ore open point from which teer than is provided in the kpit of the sailplane. Lind- ch field, at San Diego, where ok these first lessons, offers el surface some 3,000 feet by 1,000 feet wide. The ary training glider, resting he ground, with me in the faced the wind, blowing in the west, and the nose of glider was connected by 200 feet of half-inch rope an automobile standing ut that distance ahead of me. was told not to move the which was in my right but to steer—with my yn the rudder bar—directly he wake of the automobile. had pulled back on the I would have gone into if I had shoved it for- I might have driven the down into the earth. So d it in neutral, while the obile rolled along down held at twelve to fifteen an hour. The glider Assembling the Sixty-Foot Wings, and the Glider Enthusiast Wearing New Sweater Which Goes with His License

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POPULAR MECHANICS controlling, and the tra of the little rubber-tire on the glid like a= series “Z,” rather drawn dow wheels looked the letter regularly the field. On the second ru with little from more Hawle teacher, a struction Bowlus, my “dampened out” the tet dency to and followed the mobile in a very straight line for the full length of the field. Wh I came to the end of tl tow, the men in the « lifted the tail elider, hooked it to the automob and towed me backwai to the point Then shown ho to by and overconti aut near] ot back of starting I was the control it backward use forw and ra ing and lowering the t moving while being towed act the field. The wheels not leave the ground vet, but I worked at t until | Demonstrating Proper Position for Flight in Primary Training Glider; Steer- ing Is Done with Feet through Rudder Controls . was able to | which remains on the ground all the time in these primary lessons, slipped a little to the right. I gave it the left rudder, that is, shoved out with my left foot, but pressed too hard, and, in a moment, the tail in level flight position while ning on the ground, and while the glider with the foot rudder a straight line behind the tow car. When I had learned how to do all t! guid bai I was slipping away to the left of the car. Then I turned it to the right and straight- ened out, only to go too far again, when I shoved back to the left, and by this time was swinging from side to lating” as the pilots call it. regardless of my control, things, of the automobile, instructors lateral that the speed taught is, keeping balance while running up and dow: field, by moving the stick sideways. T! side, “oscil- I was over- I began to get the “feel” of balan SO MANY requests have been received for plans from which to build glider that Popular Mechanics wishes to call the attention of its readers to the ad “Don’t.” plane in every sense of the word, less a motor, and only persons experienced i: vice of the National Glider association, which is: A glider is an ait the construction of aircraft should attempt to build one. It takes as much skil to construct a glider as it does a motored plane, so it is best for beginners purchase their equipment from a competent manufacturer.—The Editor.

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POPULAR MECHANICS ng which becomes matic as the pupil gresses in flying ers. I imagine this is essential to power- fiving, and I know I got it on the nd, by running the iry training glider s Lindbergh field [ could steer accu- keep the tail up ight position and tain the even bal- of the machine nst the wind, even n towed in a curve. th the fifth lesson, ength of the tow was increased, and w car driven some- taster. I found mv- 3eing Towed in a Primary Training Glider, and Sailing Smoothly Along le aving the ground, Note the Differences in These Two Gliders by working the controls and the stick above the ground, the driver of the t had been taught, I was able to keep car suddenly released the rope, when we lider on an even keel, flying, really were about three-quarters of the way about four or five feet above the down the field, leaving me to land wit} When the car slowed, my first out the confidential, though mainly i g was bumpy, but in the third trial aginary, support of the tow line. I landed, ed flight, I was able to bring the kept the glider right side up, with the down easily and slowly and trun- wings evenly balanced, made the turn and to a stop, and even turn it about, came up smiling from my first free fligh he nose in the right direction for I felt literally “like a bird,” and xt tow. there gliding assumed for me a far greater en I had progressed sufficiently to attraction as a sport than baseball, foot e glider flying at forty or fifty feet ball, tennis or any other game I ever sa

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POPULAR MECHANICS plaved. The further I have progress in flying sailplanes, the stronger this feel ing has become—that here is an individu sport which any healthy American | can learn to play, which leads to a defi coal, the ability to flv a power plane, il meanwhile offers a fascinating pastime In order to fly the primary trainii glider, it is necessary that the pupil lear: the handling of the controls, first on ground and then in the air; second, tl he or she acquire a sense of balance, t “feel of the air,” along with co-ordination of eye and hand and foot, judgment of dis tance while moving on land or in the air: and, third, precision and quickness of n tion, until what you might call “the fl ing habit’ becomes almost involunta: Some boys and girls acquire these qual fications more quickly than others, |! it seems to me there is nothing to prevent any healthy boy or girl from learning fly a glider correctly-and safely. MOUNTAINS CAUSED BY “PUFFS” FROM INSIDE EARTH? That the mountains are the result tremendous “puffs” of internal ene from the earth at intervals of million years, is the suggestion of Prot. A Lane, head of the geology depart —_ 1 of Tufts College. One way of chec!l on the idea would be to examine the posed cycles of the puffing phenome: to determine if thev have about the le: indicated, twenty-four million years, | fessor Lane explains. It is possibl estimate roughly the age of mou! ranges. For instance, the Rockies Perl, in His Sailplane, Skimming Out over Mission he Himal ae sain : Bay, and, Below, Assembling Huge Rudder the Imalayas are younger systems,

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POPULAR MECH Appalachians and the mountains nd Lake Superior have been beveled til they have been reduced to com- vely low altitudes. Scientists esti- that 15,000 feet of strata have been ed from the region of the Rockies the Grand Canyon of the Colorado in t two periods at a rate of approx- one foot in 3,000 years. This | make the length of the cycles from five to sixty million years. FASTEST CRUISER IN U. S. NAVY CARRIES AIRPLANE FLEET U. S. S. “Salt Lake City” is the and fastest addition to the United Adjustable Reading Lamp with Rack That Books, Magazines and an Ash Tray navy, its powerful engines and trim affording exceptional speed. Be- BRACKET READING LAMP HOLDS the latest equipment of all kinds, BOOK AND ASH TRAY el is fitted to carry airplanes and them from the deck. Cruisers are Particularly adapted for hospitals or lly less heavily armed than battle- for reading in bed, an adjustable reading but are faster and powerful in of- lamp contains on its frame a combination and defense. Some develop speeds book holder and ash tray. The lamp e than forty knots. bracket can be extended to suit the eyes. = ~ 7 — Ee ‘ = — 7 aman Fe al t Lake City,”’ Fastest Cruiser in the United States Navy, Speeding Along under the Escort of the Destroyer “King’’; Note Batteries of Guns and Vessel’s Trim Lines

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POPULAR MECHANICS £ a.“ AZ ‘ 7 Fab f is : ; "/4 3 } , . oR CW a a a a ae eT. AP AL Remarkable Photograph of Osprey Flying to Its Nest with Fish in Talons: Note Position of Bird’s Wings for Landing SECRETS OF EAGLES’ FLIGHT REVEALED BY CAMERA Motion pictures of eagles, ospreys and other birds in flight, taken by Capt. C. W. R. Knight, noted English naturalist, who has succeeded in taming eagles and teach- ing them to act as falcons, show many in- teresting things about the birds, their ways of flying and fighting. For instance, a large eagle, attacked by a number of ospreys, turned on its back while fly- ing and with its powerful talons struck upward at the breasts of its The were enemies. movements clearly studied through the dium of slow-mo- tion photography. Captain Knight's studies have also shown that the eagle, like the jack- daw, sometimes col- me- lects stran ge ob- working in a field, surprised to see a beau- tifully bound book d from the skies. He at | thought it had fal from an airplane, finally saw a large gold eagle flying over the the book fallen. The bird evident] had secured the book { the purpose of addin to its nest. where SEAMLESS METAL TUBES ARE MADE ELECTRICALLY A rapid manufacturing seat v\4 tubing of copper, 7 proces > Veer 4" Ev ASE VE) © C. W. R. Knight iron by electrolysis been explained by | Jean Billiter, of the | versity of Vienna lead run continuously throu the solution and the metal is deposite it as the core moves. Later, the lead is melted away, leaving the deposit tube. core is CAN OF GASOLINE IS DELIVERED BY AUTOMATIC VENDER Motorists who run out of gasoline u expectedly late at night when most stations are cl themsel\ weary walk ii save are near a ga automat whi making its ap} ance along roadsides. Tl vender is op on the coin slot pr'nciple delivers a gall fuel in a can a coin is in in the slot a! lever pressed. @ Box-car flo jects for ifs nest. An Italian peasant, being const Automatic Gasoline Vender Which Dispenses a Gallon o> tla Can of Fuel When Coin Is Dropped in Slot ot concrete

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POPULAR MECHANICS NCREASE IN HERDS OF SEALS PERILS FISHING TRADE eals in the north Pacific have multi- I tiv to such large numbers, due to pro- e legislation, that they have become enace to the fishing industry in those tel re I s, according to Japan, who asks that strictions against killing the seals be ed to such a degree as to effect a er balance. Diplomatic communica- are being exchanged between the rovernments in an effort to arrive at 1 nderstanding. The Japanese main- that the seals have multiplied from ut 132,000 in two decades until they number nearly 1,000,000. They are icious fish eaters, chase away many eties and break the fishing nets, it is té nded. PICTURE OF WRITER ON CHECK ) } PREVENTS FORGERIES prevent check forgeries, an English- has devised a protector in the form gummed stamp bearing a picture of erson who draws the check. When heck is signed, one of the adhesive 1 i s is affixed to it, and, under arrange- ——___ ortrait Stamp to Check, to Identify It as Genuine and Foil Forgeries with a bank, only checks bearing e signature and the picture of the tory are honored. Special Concrete Building Block, Showing the Smooth, aterproof Surface, and Center Structure LOW-COST CONCRETE BLOCKS ARE WEATHERPROOF Concrete building blocks that are more economical than ordinary building mate- rials, and may be laid much like brick, have been developed by a German engi- neer., The blocks are covered with a smooth weatherproof surface coating, and the development of the cheaper build- ing units has helped stimulate construc- tion in parts of Europe. BATTERIES PLACED IN VACUUM HAVE GREATER CAPACITY Storage batteries have about one more capacity when they are place: vacuum, a Japanese scientist report recently. Under an atmospheric pressure of approximately two-tenths of a pound to the square inch, the capacity of a age battery is increased about nine and two-tenths per cent, he declared. Atmos- pheric pressure is roughly between four- teen and fifteen pounds to the square inch. When restored to normal pressure, a bat tery will not return to its natural tion until it has been charged charged for an hour and ments revealed.

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POPULAR MECHANICS ‘ SKYSCRAPER WALLS OF METAL ee 4 HERALD NEW BUILDING AGE olors to 1otograph 4 with Cotton-Wrapped , . - e Skewer Instead of Brush i‘ Sheet metal is being used largely e. replace brick and stone in the constru tion of the walls of the new Empire Stat building in New York City, and in the i novation some engineers see the haste: ing of the day of the skyscraper of ste and glass and other materials. A silve: chrome-nickel-steel alloy in angular tions, one-twentieth of an inch thick, to form a large part of the walls of new building. This metal was first deve oped for gun linings. It does not rust tarnish and is durable. The thin wa save space, cost less, reduce the weig and are said to enable the builders make larger windows for the better healt and enjoyment of the tenants... Glass, is predicted, is to be used more exte! sively in the future for partitions and por tions of outside walls. The Empire State OIL-COLOR TINTING OF PHOTOS | Pulling, being erected on the site o! REQUIRES NO BRUSHES old aldorf-Astoria hotel, wi ha eighty-five floors and will rise to a heig! Transparent oil colors now are being Of 1,043 feet. The building itself will used by both amateurs and professionals topped by a 200-toot observation tow for the tinting of photographs, canvas © mooring mast for airships, accordit miniatures and magazine pictures. No [0 present plans. While engineers see fe brushes or mixing of materials is neces- Obstacles of a structural nature to t! sary, the colors being applied with pieces erection of buildings even higher th of cotton wrapped about skewers. this, there are certain mechanical and ec nomic factors that probably will li: the height of skyscrapers to altitudes OLD LOCOMOTIVE IS MONUMENT = _ much greater than this. For insta: TO EARLY RAILROADERS elevator cables have to be made large a As a monument i heavy A pull rs cars to these gr to early railroaders, as tO" on narient toc heights, the spe an ancient locomo- : ‘pe . . ot aed oO he elevatié tive stands in a bed : e tne s : , ‘7 . ” 1 > ade ¢ of flowers near the — re ss “or . cessive because Union depot in Fe “ > Portland, Oreg. It a2 ; the harmful efi , laced tl ; > by J ' i ’ on the ears, was placed there D\ : the state, the en- Bog too much space i alee ’ to be devoted gine claiming the 1 haf Sateen yo elevator shafts. distinction of being uOE S the first in the west. - It was used by the ~ @Approximat government in 1862 . forty-three per « on the bank of the ; ; : - of the families Columbia river to , the United St carry freight above i now own radio the rapids near noe eatin 7 according to a ‘secad Historic Locomotive Mounted in Bed of Flowers near “ent wey Cascade, Union Station at Portland, Oreg. cent survey.

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POPULAR MECH NEW TELEPRINTER SENDS CABLES DIRECT blegrams as well as rams can be dis- 1 or sent direct home or office on a nter system being lled in England ubscriber or renter e automatic printer touches a switch the exchange, and signal is received lis message on the in the same man- though using a iter. Incoming res are received on inter, thus saving e for delivery. THE CAR’S WEIGHT OPENS AND SHUTS GARAGE DOORS tomatic garage that open or close » weight of the car n a slightly elevated | rm, have been in iced to save getting fi the car. The . mei ea senine 1 Ge installed German Weather Observers Gathering Data from an Airplane; the Camera m 1 install 1 “ . . Is Being Employed to Take Pictures of Cloud Formations th e garage where t exposed to the weather, there is FLYING WEATHERMAN GATHERS learance on both sides, and the DATA FROM AIRPLANE is so adjusted that it operates now and ice. Germ: weather observers g¢ dqdata on atmo ditions. The pilot and obser ] WA } in a plane equipped ing instruments, and al eras to take pictures ot OVER THOUSAND CROCODILES CARRIED BY TWO TRAINS Sixty men worked for twenty-four hours recently to unload two. speci trains in France containing nothi crocodiles. The shipment consis 1.085 live crocodiles destined for ;: zoo, which is a sorting center at c station for various animals being Which Swings Upward Automatically n Car Is Driven on Inclined Platform circuses and other zoos.

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wooded hollow, a tage was occupied b man of all work. Or: count of numerous t there had trouble bet passes, much the workman and the cupants of the big Bad blood Was espe strong between the borer and the son-in night the had gone One into tov the theater. The went to bed, leavin son reading in the lil which Was sepatl from the entry hall By JOHN F. COGGSWELL .7 IS well-nigh impossible to do murder bv gunfire without leaving a clues, as clear as a printed page modern firearms expert. From the 11 bullet alone, he can tell the tvpe ber ot the weapon used, its maker a1 ae iker ot the projectile. His knowledge of the manner in which men fall when shot to death, combines with accurate measurement of the angle of penetration e fatal bullet or bullets to reconstruct with a veracity that is the des- The point of entry gives of the distance between mute evidence gun muzzle and victim. “Here he states, and usually he is correct stood the victim and here the killer,” in every detail as he sketches a word pic- ture of the murder scene and points to the criminal. Let us consider an almost per- fectly planned crime and watch the expert carry on to a successful conclusion. An old gentleman, with his son and his son-in-law, lived in a mansion on a lonely suburban estate. Behind the estate, in a 194 Examining the Interior of Revolver Barrel ar ratus for Photographing Gun-Barrel Interi pair of heavy portieres. The eld m hardly fallen asleep when he was | by the sound of a gunshot, runnin steps on the floor below, a slammi and a muffled cry. He shook himself awake, called « his son, but response then made his cautious way down On the floor of the hall, close by the lay the huddled body of the son-i1 flat on its face, a gaping wound received no

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me Cog. 3 ogee ~~ # ‘—s ¥ 7 istructing Members of Homicide Squad How to Deter- Expert Ir proximate Angle from Which a Bullet Was Fired; the Silhouette Target Is Especially Useful for This Purpose head As horror, he ) be. The local e within a few he hospital and began their in- + ic had hit the son-in-law the eves, emerged the skull and buried itself deep in Such tre- at a slightly »f the doorway. striking energy gave proof that yn used must have been a hig! 1 OTK ¢ open basement ttom up. window stood Beside it ava blood

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196 POPULAR MECHANICS head. That angle of fire, extended at scene of the crime, proved that the bu in the woodwork was likely the fatal . Added and more gruesome prooits bullet had carried along on its flight deposited on the scarred trim. When the firearms expert examined shattered woodwork, where the proje had plowed an entry, he found a fla the son’s story of the crime. Had shot been fired from the rear of the way, the bullet would have gone n straight into the wood, after travei the victim’s skull. But it had cra through a long section of the wood acute angle, and when that angle laid out on the floor of the hall, it p straight to opening bet) the portieres. , P The expert tack with a knife. an I , . carefully, ret The fleeing man - ' every tragme had leaped to the tl . : se . ne projectile barrel, dived tn. the wood While the jacket was through the open window and _ van- ished into the night Search of the workman’s prem- about four-fift its length an arated into ises revealed a .32 bead P : i wistec yort special rifle, hidden _ E ie . an ie lea in the woodpile, a recently discharged shell in the barrel + He was arrested nd charged with the crime He admitted i toutly main tained his innocence. The gun, he claimed, must have been stolen durin his absence from home, from its usua closet. lo the suburban pol ce chief, it looked ike an air-tight case against the work- man. Motive, mode of entrance, oppor tunity and weapon were, seemingly, all present and accounted for. The evidence } i vefore any appeared good for a conviction jury. However, in order to cover all an- gles, the chief called into the case Capt. Charles VanAmburgh, ballistics expert, of the Massachusetts department of public safety. At the morgue, the expert determined, - by measurement, the distance above the floor of the points of entry and exit of the Three Shots through Fabric, Each Fired from : : Sage Chae ent Range; Two Murder Clues, and Lead Sp bullet and its path through the victim’s Wallpaper and Plaster on the Bullet

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POPULAR MECHANICS cked into bits, the ing marks of the ipon. were intact on hank, Bullet and rifle e taken to the labo- ry. lere the process of de- ning the caliber and of a discharged et and the type and f gun that dis it demands training of but is perfect, } rehensible to th nd. The bullet rticular case 1 +} t rough just t the entire s. Measure- of the intact proved it to four-thou Iths of an inch ller than the .32-special jectile. That uch. The ve human hair and one- susandths of neh in diameter. Pr tographing Gun-Barrel Interior; Center, Two lls Compared, and, Bottom, Gun Parts That Caused the Markings Above

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198 POPULAR MECHANICS Most of the measurements are micro- pert found the weapon he was look scopic. In depth of groove there is but for. The mortal bullet had been fir : a seven-thousandths of an inch between the from an eight-millimeter-caliber Aust: deepest and the shallowest—twice the army rifle, he told the chief. diameter of a single hair. Such a dimen- When questioned, the father reme sion is measured through a calibrated eye- bered that the piece, the measurements being read from a scaled dial on the focusing screw. son had brought hi from France, after the war, some sort a foreign rifle as a souvenir. He was To establish the rate of twist, a photo- der the impression that it had been thr micrograph, showing the bullet in mam or given away some months previou moth proportions, is made. Certain But it hadn’t been. measurements—the gift of Captain Van- Amburgh to the ballistics world—give the length of barrel in which the rifling a pantry close to the head of the base: makes one complete twist. Widths of A search reveale: a recently discharged shell in the cham! in a recess beneath the bottom drawe: stairway. lands and grooves present a variance up Then the expert gave his version of to nearly three-hundredths of an inch, a crime. The murderer stole the work: world of difference under the expert’s gun, discharged a shot from it and microscope. l. creted it where it was found When the firearms authority had com- it! nad night of the crime, he slit the p eted all these measurements of the bullet screen and gave the oper pet hat had slain the murdered man, he found blance of | a forced entry. Chen that they tallied with nothing described 1 his stand behind the portieres to av in his commonly used tables, let alone the return of the son-in-law. He w .32-special, so that weapon was eliminated with the war weapon, which he from the case. But one thin; > had de- from the recess where it had lo termined in examining the bullet put him awaiting an opportune time for tl on the right track. Its jacket was of soft ing. steel instead of the usual copper alloy, The doomed man entered the doo In spite of the prevailing impression, closed it behind him. A low voice there has never been a steel-jacketed bul- let manufactured in the United States 1 ( to him from behind the portieres if _nor turned to face it. Then the mu | in most European countries. However, pulled the trigger. In ninety-nine during the World War, Austria, short of out of a hundred, the experts say, a p¢ copper, did jacket bullets wit] teel. n shot when looking directly into the the table of arms and ammunition muzzle, has been spoken to ji by the central powers in the war, the ex- the fatal shot. The Riot Squad Receives Instruction in the Use of a Machine Gun, So That They May Match the P ficiency of Some of the Gangster Crews in Handling This Weapon

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POPULAR

murder accom- the killer ran the hallway, thrust fle back ‘e beneath the into tie slammed the sound h id mis- MECHANICS

Jnusual Position Assumed by a Wrecked German Ship HH ty son admitted his guilt roborated the expert's word pic- per cent of the he United States. is found to have been fired from 38-caliber revolver or automatic But keeping to these types affords tection ti he criminal For no been found not mark RADIO AIDS IN LAYING PIPELINE Wa called upon <¢ an assistant rineer in charge a lake was dis aving a pipe in Germ The work as it Was ot the pipe 1 +1 length, neously along its entire hone was installed beside the engi eveling instrument transmitted, first to a motor truck itha receiving set and loud speaker amplifying power, and thence to the workmen ier Beam Ends with Propellers and Rudd s0T avdo\ SHIP’S TRAGIC END IS SHOWN IN UNUSUAL PHOTO ELECTRIC AUTO AS CADDY SERVES CRIPPLED PLAYER Crippled Golf Player, and the Carries Him and His Cl

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200 POPULAR MECHANICS SPEARING SWORDFISH FROM A SWINGING “PULPIT” warks, the nest swinging from the ma head and this framework. It may raised or lowered as needed, but, w! in use, is about five feet above the wat The harpooner drives his instrument i ) \ or 1 x a \ sg As \ J { \% LA y 7 Sy Sp i } 5 — > Swinging “Pulpit,” Ext: from Forward Bulwarks Fishing Boat, on Which pert Harpooner Stands ww Spearing Swordfish ~“ - ” a swordfish by ~ ~ downward with a foot pole from h From a swinging platform or extending thirty feet in front of the ship itself, fishermen of San Diego, Calif., har- poon swordfish as the motorship to which the pulpit is attached runs head-on into the The pulpit is fastened to the school. steel bul- a rigid framework torward CRUDE OIL SEEN AS AUTO FUEL WITH DIESEL ENGINE “Gasoline buggies” may be things of the past and crude oil the predominant fuel for automobiles, if development of the Diesel brings results promised, in the opinion of During a recent test with engine now engineers. an engine of this type, designed primarily for marine “pulpit,” form, the harpoo: maining in the fish while the pole 1s drawn. Nine hundred feet of rope a1 tached to the harpoon, and frequent fish weighing from 400 to 1,000 por fights at the end of the line for an The pulpit is hauled up with cable engine when not in use. sedan and a roadster were ru average of twenty-fiv miles to a g of six-cent crude o! ‘or a total dist of 6,000 miles. The only marked d ence as compared to the ordinary ga engine, was a little sluggishness o1 pick-up from stop to twenty mile hour. The top speed was fifty-five an hour. That the record tor a sedan. In the roadster, better acc: 7 use, a 17 Me was

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POPULAR MECHANICS 201 z ‘ion was obtained and a top speed eighty-eight miles an hour _ recorded. While the Diesel Pigg rs fuel economy and elimina- whi of the usual ignition sys- ta its original cost is still too _ h to make it entirely practical a wide adoption, and it is too i vy. However, engineers be- > ve that further research and provements will overcome > e obstacles. ENERGY OF WORKERS IS MEASURED BY TREADMILL much energy does a man nd while pushing a wheel- = 2 ge: igo ote: hill? Science — — g A Ay as, Hooks fisteat’ of C — ae the exact answer by means re nteresting apparatus devised by a “gKY HOOKS” TO SUPPORT ROOFS “ae, nch professor, Ww ho has rigged a tread- OF WORLD’S FAIR BUILDING | arrangement whereby accurate stud- be made of the physical reactions Among the unusual architectural fea- ons to various tasks and their fit- tures of the Chicago World's Fair Cer for different kinds of work judged. tennial celebration to be held in 1933, will = ments connected to the subject and be roofs supported by the so-called “sky — moving platform on which he hook” method. Tops of the domes at register the increase in tempera-- either end of the huge Transportatio1 h in Es { the man’s blood, its pressure, the building, according to present plans, will a ue experienced, and amount ofenergy be constructed in this manner. Instead rth in doing this task. The appa- of being held up by interior columns and ta! tells the effects of walking, of run- girders, the roof is largely supported b t and of doing various kinds of work. a system of “hooks” or specially braced —_ and arranged members r that hold the weight usu ally laid on columns ot al other units inside the 1¢1 | building. This plan will p afford an interior unob in | tructed by pillars, al ble the sky hooks will also harmonize with the | unique appearance of the building itself, which is rt to be covered with a spe- a 2 cial metal on the outside dis and will have no win- dd dows, all the lighting be- 5° ing from within. Thx : oO accompanving illustra- miles tion shows a scale model ive L of one section of the _ ~~ Transportation building acct | Which Accurately Measures the Energy Expended by the Person Walking in It in Performing Various Kinds of Work and the sky-hook roof.

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‘ | | dD Courtesy Smit ian I Lieut. John Fitch’s First Steamboat at Its Public Trial on the Delaware River at Philadelphia, July 27, 178¢ from a Painting by Clyde O. DeLand By DON GLASSMAN A Mee \N invention stabilizes na but, at some later date, we may tional wealth and gives health to their failure. Still others are so crud every industry. they seem to have little promise; yet Day by day, come scraps of paper from may yield wealth and fame.” inventors. Some show crude drawings; The chief of a division corroborate others employ poor English. It is the ex commissioner. “I have been here aminers’ business to judge an inventor’s teen years,” he said, “and am still creativeness, not his grammar. Has this to pass judgment on the financial wv thing been invented before? Is it a modi an invention. I issued a patent to ‘ fication of another invention? Is it prac Campbell Carson on a machine for tical? The examiner searches. Hesearches ing copper-smelter furnaces. It long and late. In four cases out of seven, look very unusual. It was all in he awards the inventor with a certificate business. Well, recently we hear and admits him into the company of Mar- Carson had recovered millions of coni and Bell, Morse and Berliner, Edison from smelting companies that ha and Goodyear. his invention without his sanctiotr Commissioner of Patents Thomas E. inally, he had refused a paltry $3.0) Robertson told me that he is unable to _ it, holding out for a royalty basis. recognize a great invention before it has “Very often, the first news that won a place in the world. vention is successful comes to us t! “T cannot, of course, express opinions newspapers or popular magazines on the merits of individual patents while “Perhaps you never heard of an they are in this office,” he said, “but Iam locking shingle. It helps to make frequently upset in my estimate of what water-tight. A very simple inventiot certain inventions are worth. Some pat- that shingle pays the patent ents that come here look very promising; $400,000 in royalties every year. >?

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ee Pee ne a Transcontinental Train of Today Being Pulled across the Rockies by an Engine Such as 7 Stephenson’s “‘Rocket’’ That Ran during the Earliest Days of Railroading e of the latest improvements in steel mands the assistance of tools and force truction is a process of welding gird- invention flourishes. electricity. It eliminates rivets. A Surely, an inventor needs money, but keleton of welded girders is with- in this he is no different from 1 fell and the inventor claims that it men. In the throes of creation, an tronger than a riveted structure ventor resembles a write Lhe « be used in bridges as well as build his head are manufacturing ide cre truction, and no doubt can be iting situations. There i plot n to ship hulls, too. end product in every machine. Some part her patent was obtained on a_ play leading role othe em r char lor curing concrete roads quickly. acters. The importance of an invention ly, this requires several weeks. is the measure of the inventor: , Cue i lway must be kept damp or cov- chine, every device that passe throug th some protection such as straw. the patent office bears the trade-n O mist created a colloidal emulsion’ the one who conceived it: it carries the e property of drying slowly. When mprint of his mind. Invention ke 1 to new concrete, it hastens the plavs and plots, have persor é process.” Since b 1111s ind de i r¢ ¢ { i ' public has misjudged inventors. sole assets, he is an individualist, like the revailing notion is that invention is writer and artist. Inventions cannot be sion which men practice for profit. manufactured mechanically, nor can they it is only partly true. If invention be made to order All the great corpora purely business, it would soon be tions maintain elaborate research staffs. itized ; corporations would develop yet they are dependent on the output of lies. But today, as always, the independent men who cultivate a natural inventor still holds the strong- instinct for contrivance. posts. No great research labora- Many corporations have hoped for the in oust him. Wherever man de disappearance of free-lance inventors 203

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ceive the radical innova- tions that change the globe’s face. The free lance has those rare dreams that erect indus- tries and generate vast wealth. For years the science of radio was afflicted with a howl which came from the vacuum tubes. The corporation staffs sought to kill the howl. Camea Russian inventor, Leon Sergyevich Theremin and produced a device that converted the how! into actual music. No less amaZing is the case of Colin Kyle, a ¢ ifornia school-teacher. He applied an age-old principle to a modern loud speaker. Radio found a golden voice; Kvle found fame. Age seems to have lit tle influence on an inven- tor’s talent or activity. Edison earned his retire- 204 POPULAR MECHANICS ment long ago, vet he attacks the m dificult work zealously. He recently vealed that rubber is found in a great riety of plants, and some may be exploit llv. The common goldenro an example. commercia When he invented the acoustic tile for correcting echoes and reverberati in auditoriums, Emile Berliner was past middle life. He had already inven the telephone transmitter, the radio crophone and the disk phonograph ec Whenever I visited him, he was busy proving his old inventions or devising ones. Besides his own work, he wa terested in other sciences. His helico was the first successful airplane of type. It is now in the national muse The geographic yy tribution of invent 4 has just been called ™ 74 the attention of the ‘ ¥ ent office. One in eator declared th Swiss are the m ventive people; on a population-t basis, Swiss citizet other nationals number of patent out. His figures that, in proport population, Amer , of LY citizens take out FHS FARBE thirds as many ARG? AD BY here and about ¢ us ‘AMD AOP AR itteet \TIR AGM AN Ss OF fee TLOUN kee + +1 © . teenth aS many poe In 1925, per (NCIS OF 1% OMS OMS NO ES inhabitants, Switze rid PIBSY SO SPOOF OEMA Ms sis teenies ecehashenas SULU AY SR UL EEO THE ‘ Vite DIA TOF Yess B YHKOUGIS. Jay us 4 Model of Fitch’s Railroad Locomotive; the Fitch Memorial Plaque Capitol at Hartford, Conn., and Model of Fitch’s First Screw Props Is Credited with Being First to Apply Steam to Propelling Ves

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POPULAR MECHANICS 205

299, Germany’s 271, France's 195 iin’s 188, Belgium’s 180 and United es’ 160. In number of patents granted heir own nationals at home the follow- ratio obtains: Switzerland, 542; States, 382; Belgium, 283; France, j c \ustria, 239; Britain, 191; Germany, = \ e case against American invention nted iid seem very distinct were it not for difference between the Swiss and ican patent systems, which the in- rator failed to point out: While erland employs the “registration” America uses the “examination” Almost anyone who pays the fee may have a patent registered e tzerland—although there are certain vhich the specifications must fol- sut the American patent office rejects edi | t aS many applications as it accepts.

e l one considers ea bounded by on-Dixon the south, lian border north, the ppi on the 1 the Atlan- 1 on the east,

inventors were never more fertile, nor did

they ever receive ls more in- and inven- el talent than in it her spot in the ire certain districts Invention 1 Connecticut, Ne never elevated rk. New Jerse. igher level id Per 1 wher e pop y bi , ‘ > concentra \ n of inventor! Euro ns \ ler and que on he \ kee pro uction in 1 en yn nce American rang om European ock e only ¢ that ie United State cher shes and stimulates 11 tors Our govern ment makes special laws to protect them. It vives a a a _ patents which guarantee te <5 ug, sa oe mer . nels against infringement The government recog ngines Retain Many of the Essential Principles of These Early In- nizes three parties that Richard Trevithick’s High-Pressure Boiler; the Selden Automobile, 7 . : and “Puffing Billy,” Built by Hedley in 1816 benefit by inventions:

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206 POPULAR MECHANICS

of Edison’s phonogray Martinville’s instrume consisted of a thin me which was delicate le brane to tached a The membrane y stretched over the row end of a funnel. 1] end of the lever placed against a pay cylinder covered When sounds transmitted to the me soot. brane and the c was rotated, the osc tions of the mark e1 recorded, and _ trac of vibrations obtai1 The case of (| Tellier is another e ple of a brilliant Fr man who found

the inventor, the manufacturer and the yublic Alwavs it is the I consideration in a dispute, for inventor who re- ceives fit the aim of American legislation is to give him both even though the manufacturer may suffer the greater loss In American social life. the inventor col l espect ind ict ration He is 1 ve red as e root and foundation ot ou nat ) i] Stre rt] l id ¢ ilth No othe ( nt omel uc id ome poun- ties for |] rl ] s ditfere t } Europe | iml< Ib a ( ¢ po He € le € 1oOn the most imaginative In chemistry, in aero nauti n engineering and in architecture, Frenchmen contributed many basic ideas. But because her patent laws are defective, France was unable to give justice to her inventors If France toward might have encouraged him to perfect his “pI honoautograph” 1857: it was without doubt the forerunner had been more sympathetic Leon Scott de Martinville, she which he invented in

At the Controls of an Early Airplane, and R« Propeller Developed by Army Air-Corps Eng cooling devices and equipped a his invention. When turned from South America with a of meat, with ‘he ve French cattle raisers alarmed over this sudden competiti had the shipment condemned. But taken to sold and sritish purchased Tellier’s inventio: trifle and organized refrigerated London. eatel ship lines. The whole system ot refrigeration and_ refrigerated c started with Tellier’s invention.

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1854, when Alex- er Graham Bell child in Edinburgh, tland, Charles Bour- published an ac- int of how he had ob- ned electrical transmis- of speech. He set up first telephone appara- in St. Cere, and spoke his friends over rt line. Frenchmen ed at Bourseul. The ernment, no doubt, his article in L’Illus- was 1 yn, in which he rec- ended the use of a which vibrate with the pressure of ait hus open and close ble plate ectric current, and a plate at the re- Station. land has good pat- but the adop- bor-saving ma and has been slow. household sibility of inven- Canada is un

\n undeveloped Modern he Canadian trail. In toward Cana- The re- imended patent laws provide both and encouragement. duction. nerv blazes t + titude inventor re not unlike Americans. CLEANER KEEPS STEEL TAPE FROM BECOMING RUSTY

Keeping the steel tape clean and free from rust is simplified with a small pad that is snapped on the tape the case. A scrap- ing side of close to

two

lips extends away e case and as the tape is drawn these lips remove dirt and dust

POPULAR MECHANICS offers the in YM MULL WH ever) incentive The Life Stories of Two Familiar Tools; the Hammer and the Saw from the Stone Age until the Power Age of Today

Y Y VMOU,

‘ y\ <_ Gi while the oiled pads behind them clean and condition the steel before it enters the case. The pads are interchangeable. The cleaner is intended to prolong the life of the tape while keeping the characters from ra ; rr becoming disfigured or obliterated. PRINTING PLATE MADE QUICKER BY METAL SPRAY PROCESS Metal plating by spraying, a process evolved by a Swiss engineer, is constantly invading new fields, the latest develop ment being a “gun” by which even sucha | refractory metal as chromium can _ be spraved on other metals and materials. The process has been applied to the mak- ing of printing plates as a quicker substi- tute for the slow electrolytic method. By metal spraying, such plates can be pro nutes duced in from ten to fifteen mi

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208 POPULAR MECHANICS ailerons and the rear elevators. The devic« mounted on an air « inder and supported an extension rod. W] at rest, the air pre equals the weight of ; and plane, when in motion, the senger creased pressure cau the ship to move up down on the rod as ir climb or dive. The p duplicates the mo ments of the auto dr with the plane contro! MINING DIAMONDS BY DIVING Interior of Pittsburgh Motor Coach in Which Passengers Are Entertained with Radio Programs; the Driver Operates the Radio Receiver BUS IS EQUIPPED WITH RADIO TO ENTERTAIN PASSENGERS For the entertainment of passengers, a Pittsburgh bus company has installed ra- dio sets in the motor coaches used on the city streets. In addition to driving and taking fares, the trols the bus operator also con- radio set from a dial on the in- strument board. AIRPLANE ATTACHED TO AUTO AIDS IN TRAINING PILOTS To aid in training pilots and give pas- sengers the thrills of flying without actu- contact Picking diamonds { the dangerous rapid the Araguaya river in Brazil, divers been risking their lives and meeting tragedies in one of the most pei mining exploits in the world. The were time ago river bed between steep cliffs and discovered some the water was from twenty-six to Stones valued at mn $250,000 were gathered in a comparat feet deep. short time, and a diamond rush foll The sharp rocks of the cliffs cut the lines used by the divers, footholds insecure and one man was swept and lodged between two bowlders His bod) recovered a few days later, after th: he could not be extricated. had been S 1 the ground, an airplane is attached by a metal frame- work to the rear of an automobile, the plane itself extend- ing over the top of When the driven pilot keeps his plane on an even keel by manipulating stick and rudder bar like those on an ordi- the car. auto is abou > the by rains washed it from its moot At the wot along the wire cable strung acro tO hold boats wv I are used (to r the gem-bearing minerals brou up by the d who descend t: bottom of slo stream The nary ship Iront 4 wings act as This Combination Is Used for Training Aviators and to Give Passengers Flying Thrills in Safety sometimes on cial ladders.

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POPULAR LASS-PACKED MEALS COME READY TO SERVE rle packages holding in individual containers a sufficient quantity and of foods to make a complete meal placed on the market to save me of a busy housewife faced with ergency. The foods are grouped prehensive, well-balanced menus e entire meal is ready to serve when Quantities for two, three or four ns may be obtained in several differ- of including the formal dinner, light lunch, One juice cocktail, | olives, boned chicken, string beans, pes packaged meals, linner and breakfast package. contains tomato cranberry sauce, sponge cake with te sauce, salted nuts and coffee LYING REDCAP TAKES BAGGAGE ON AERIAL RAILWAY ks and wagons for hauling parcels .vgage from trains to bag | gage room 1 railway station have been re- by an overhead trolley and basket port this luggage. The device re- les an enlargement of the depart- tore parcel-and-cash carrier system operated by one man who rides with a veritable aerial “redcap.” basket } ead Trolley and Basket for Transporting Bag- gage and Parcels at a Railway Station MECHANICS Talking Clock That Speaks the Hours and Half Hours; It Also Contains a Radio and Phonograph TALKING CLOCK SPEAKS TIME ON HOUR AND HALF HOUR After considerable experimentation, a Philadelphia man has produced a clock that speaks the time. The instrument con- sists of a combination talking clock, radio and electric phonograph, all installed in a grandfather case. The clock speaks the hours and half hours, may be made to of cheerful greeting, morning—six o'clock.” tains not but also tell the time in the form such “Good The cabinet con- with dy- namic speaker which is used for the talk- +1 only a as an electric radio receiver ing clock voice, the radio and the phono- graph reproduction A SANITARIUM FOR GOLDFISH In Toronto there is a special hospital and sanitarium catering exclusively to goldfish. There the fish often undergo surgical operations and are treated for many different kinds of ailments. It has been found that the fish are subject to many ailments that afflict man, and for many diseases the treatment is the same.

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POPULAR MECHANICS bird killed, however, two to four you egrets died of starvation in the nest. The birds originally were abundant from Great Lakes to the Gulf of Mexico, finally were killed off until they mad last stand in southern Louisiana Florida. Private property at first wa aside for them as a refuge, and Louisiana, Florida and California pa iaws protecting the birds lorever. ~ THOUSANDS CAN HEAR PIN DROP IN HOLLYWOOD BOWL Through sound reflectors stalled, 25,000 persons can hear a pin mn the stage of Holly wood bow] ly tests a birdshot weighing about thousandth of an ounce was dropped « inches on a kettledrum and the noise heard in every part of the bowl. The lector is a half shell of a huge cone, fi five feet high at the front of the stage eighteen feet at the rear. It is ma thirtv-six tons of structural steel padded inside and out with sheets o bestos. So carefully has it been des 1 Museum Exhibit of the Beautiful Egret Whose Snowy that it directs more sound to those > »s Almo sulted in I Extinction . ° Plumes Almost Resulted i ts Extin« feet awav than to persons in front MOST BEAUTIFUL BIRDS SAVED seats, because the close-up audience FROM EXTINCTION BY LAW enough sound from direct waves Boal _ electrical amplifiers are used. The ref ] €egisiative and pouice powers Ot several ing cone ce mounted on a portable b states, and tunds supplied by interested persons, have been used successfully to save from virtual extinction the American RADIO LOCATES WATER PIF egret, probably the most beautiful bird in WITHOUT DIGGING this country. A _ . : ssi few vears ago, these f =. B 2 lo prevent birds. were slaugh- ; | ging up the stt tered in large num- over a considet bers to obtain the - , area, a tIrame fine plumes worn . lig ’ aerial and what ] sembles a port by the female snowy egret during wireless set art the breeding sea- ing used in Lo son. The plumes, to locate wut ground w mains. When known as aigrettes when worn on wo- men’s hats, sold at M, lee } | aerial $50 an ounce, and as os above the pipe each female yielded | instrument tr: about a dozen ts mits a buzz w ’ | is heard by the erator through phones. is dire plumes, represent- ing two ounces of feathers. For each Using Radio Apparatus to Locate Buried Pipe Line

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POPULAR MECHANICS 211 RANGEST TUNNEL TO JOIN EUROPE AND AFRICA cebuche ; ‘ 4 | _s\ | Gibraifar ‘on “J # Ss ie ; / 4 Joints concrefed as each Tube Section fis , A leodh / “ . | ( i ‘ t odjusta b le dur erectidin A\nchering Cables of } uno\xidizab/ie Steel jie yon. Corregive casings } t, Popular Mechanics Drawing of Proposed Gibraltar Tunnel, a Huge Concrete Tube, to Connect Continents of Africa and Europe across the Narrow Gap of the Straits of Gibraltar

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212 POPULAR MECHANICS QUICK FREEZING PROMISES TO LOWER FOOD COSTs Meats and Fruits, in Uniform, Handy Packages, as Prepared for Consumption after Rapid Freezing, and 7 Machine in Which the Products Are Frozen Perishable foods of almost every kind, torm much of the nutritive value sold in uniform, frozen packages with a flavor of the product escape and minimum of waste and at probably lower There is but little cell destruction prices, will be available at any season of rapid freezing since small crysta the year asa result of a recently developed formed, hence the foods retain thei: quick-freezing process which keeps foods inal flavor, freshness and nutritiv with no loss of flavor or nutritive value. ities and at the same time are pt Fresh vegetables and fruits, oysters at all against decay. times of the vear and other foods usually To freeze foods by the new meth« procurable in palatable condition only at are placed in a machine, the chiet certain seasons of the vear, can now be of which is an arrangement of two enjoyed at all times. ble, moving belts of monel meta The virtue of the rapid freezing as com- above the other. The cartcns pared to the usual slower processes lies lower belt are drawn into a freezins chiefly in the fact that when the cold is _ nel while the upper belt drops dow: applied quickly and freezing is fast, much the food but not so hard as to cru smaller ice crystals are formed. In the When the machine is properly lo slower methods, the crystals are larger. calcium chloride brine, at a tempe! hey break the tissues and cells in meats of about fifty degrees below zero, is and vegetable products with the result, against the reverse side of each bel! especially in meats, that the liquids which none of the liquid is allowed to co a

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a ept indefinitely. VACUUM CLEANER FOR STREETS with the food. tense cold quickly ites the belts and roducts, freezing in from one to two 1 forming small tals that do not up the cell tissues lamage the food. elopment of the it is shown, will t the producer to ind ship only the xr grades and the cuts of meat and hile the other parts ve utilized for by- 1cts The yields of it seasons can be ed over slack har- thus equalizing et conditions, and ng expenses will be ed through reduc- waste and extra g. Stores selling ozen products will quipped with large rerator counters and where stocks can embling an army in appearance, a cleaner employing vacuum principle is n Che POPULAR MECHANICS oy ~ ina ~ “sn ' Storage Tanks at a Big Dye and Chemical Works; the Odd Shape Affords Large Capacity and Eliminates Unequal Strain being gasoline-operated used in cleaner eps the streets, and also sprinkles and them in one operation. Sweeper That Works Like Vacuum Cleaner TANKS SHAPED LIKE BALLOONS FOR GREATER STRENGTH Huge spherical tanks, resembling large balloons, are being widelv used in this country and abroad tor the storage of chemicals, such as are used in the manu- facture of dyes, and for other liquids. One reason for the construct n of a tank of his shape rather than a cylindrical or rec tangular one is that there is no undue strain on any one side of the tank either from the weight of the liquid or the pres sure of gases that mav form inside: less metal is also required to build it @ Fireproof clothes for airmen are being used by the British air forces.

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By CRAG DALE | OW oiten have you | “They don’t make in the truth is there in it? rood old days”: To answer these questions, to speed up the wear and tear of time so that a few hours will reveal faults it ordinarily would take a lifetime to discover, is the job of Dr. Ellery H. Harvey, head of the “prov- ing plant” of one of the greatest chandising houses in the world. There mer are some queer jobs in _ this 214 how 35. 000 produ he gaff.” He “Ammercrial det OMMercial ae ight on flaw Ss in that eoods Measuring Effect of Synthetic Sunshine on Paint Sa ples, and Testing Absorption Qualities of Cloths; C ditions of Natural Exposure Are Accurately Duplicat

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as aey Us One of his tests lucted to how the platinum tip on foun- pen points would last. He tructed a | that traveled in a chang- most in- recently was determine motor-driven rcle over an ordinary of writing paper, and How Durable Are Dishes? With This Swinging Weight, the Tester Can Determine the Strength of Blow Required to Shatter Plates, Bowls and Other Dishes ch held the pen at a constant angle. rce feeding of ink kept the flow con- nt. One pen traveled 156 miles before topped writing. That, he declared, equivalent to 123 years of average use. qualities of silk dress ds began to give Doctor Harvey much thle when women began to insist on ht Rayon stepped in and added e trouble because manufacturers of silk coods, in e wearing , colors. some instances, at ted to lessen the cost of silk by using “filler.” This filler was the in the fabric and is Tin chloride woot made of tin oxidizes under », and perspiration breaks it down Laws of trade permit the use of much as twenty-five per cent of tin ride in making silk goods, but some utacturers, spurred by 11, hot competi- used as high as fifty-five per cent of n. In those cases the fabric break- was rapid. Chemical analysis, of course, would dis- close the quantity of tin in the goods, but not the length of conditions under The public wanted silk, or something that looked mighty like it, and the merchants had to provide it i it were half tin. So Doctor vised machine; wear average even ii Harvey de- that would do in a few minutes what weeks or months another one of wearing would do to a silk dress Op erating at normal room heat under ultra and violet rays in reasonable humidity, Doctor Harvey’s abrasive machine w ld seventy-two rubs a minute on the friction of the material rub- r against itself. Three minutes of rub snough for leavily filled silk, while that containing no more than twen ty-five per cent tin stood from three 1 four times as many Was ) rubs before breaki down. By using the same machine, without the addition of ultraviolet rays or humid 215

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POPULAR

itv, a piece of dium-w eight suiting for me found to sti 50,000 rubs at rate of seventy a minute. gives an idea though indefinite since conditio1 s must vary with in- dividual instances, of how many one might expect to s!1 ered with like out his trousers One of the mi peeding up time olved by Doctor Harvey the lasting qua lacquers and asp! “The flair for ight color lino leums, on weatherboards and throughout the house. gave us a | f trouble at first.” he said. “We just didn't know what we could guarantee. But now we have a machine which can tell us quickly about it. <A piece of linoleum, for in- stance, is no better than the paint that is on it. When the paint breaks down, the whole fabric begins to go. “In our ‘weatherometer’ we have effects ECHANICS “equivaient to one day OAD

ons, The painted he machine. and nty-four rain solution "1 t YF ulal nce a the area ot piece of metal operator then plies a platinu needle, attached i set of radio cely ing earp! O1 through which istens. If there been anv breal Measuring Strength of Saw, of Furniture, and t! Wearing Qualities of Leath er Samples; Special M chines Had to Be Invented for These Tasks

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POPULAR MECHANICS ‘ly. tin rouble. too. heir many mixture >» heen diffi- SO that the, ining the Stiffness of a Golf-Club Shaft; Testing the Strength of Rope, and Putting the Springs and g of a Mattress through Tests That Reveal Their Resilient and Other Qualities ; the Log Pounds the Mattress at Different Angles and with Varying Force to Test Sample’s Durability

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POPULAR the brilliance of sun- shine. So far, three years has been estab- lished as the longest time such paper can be warranted not to fade. Another apparatus of more than passing interest in this labo- ratory of unusual things is the machine for determining the resistance of china against breakage. For this test a four-ounce steel weight is swung against the plate in | | MECHANICS Harvey will give them his official appr is enough to discourage the best of t A log is hooked up to machinery SO it pounds the mattress from almost « conceivable angle. If a mattress st up under that for a week, it is good lifetime. “Taken as a whole, a compariso quality between an article that is n today and the same thing of twent years ago will show many things are so good today,” declared Doctor Hai “On the other hand, the public is n much interested now in how long a will last as how it will look. I’m speal of clothing now: women’s clothing in ticular. But bear this in mind: It quality of silk has deteriorated, very deterioratio placed silk 1 } the reacl OK | of who could not it years ago. “But it 1s d to discuss the que ot relative go ot things withou vancing the tl that today we ha many more tl than we had twe five years ago. | year sees additior the list of thing ever-increasing arcs to measure the foot-pounds of resistance. The trick is to ob- tain a really thin dish which will stand some bumping around—one which the _ hur- ried housewife can drop occa- sionally without hearing the heartbreaking clatter of crash- ing china. Two and a half foot- pounds is established by Doc tor Harvey as the smash that a plate or cup must stand be fore he can accept it. And mattresses—what they go through before Doctor Driving Hacksaw through Steel Bar; Testing Rubber Fabric’s W proof Qualities, and Electrical Test on Paint; the Needle Mak Electrical Contact if Paint Has Cracked on Metal

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POPULAR MECHANICS desires. What re enabled to save ¢ silk with tin or a suit with and cotton, hey rr some ol tems which, ke life more and which he reach those thing were consid -ife Guards and Their Rescue Plane; a Lifeline Dropped from the Plane to Persons in Distress Is Carried to Shore by a Torpedo just a LIFE GUARDS USE SEAPLANE not be so good, IN RESCUE WORK vere in times hat very truth Life guards at Seaside, he undeniable airplane in rescue work. The craft car te! ries a torpedo to which | faster ed a long — rope attached a life preserver. Che SPRING-WIRE FUR STRETCHERS (© “évins REPLACE WOODEN FRAMES persone ire stretchers r the drying of ( 1 the preserver to 1 | le torpedo Cat ries the line hore, the method bein; juicker than laboriously ; nittied wooden NAIL-LESS BANDS FOR BOXES | ‘ REDUCE SHIPPING COST iess gen- Packing cases and boxes are since the ened with steel band ‘rs have used s fastened Indians instead of lings tot ] T urpose, it necessary to e a large as rtment of irm if desi vooden frames to ‘se of the accommodate va- and the band rious sizes of pelts, makes it practi- he wire frame adjusts itself to any cally impossible The spring wire holds the sides for anyone to allow sufficient circulation of air, break into a case drying the pelt more quickly and so protected, with- nating wrinkles. Prong steel clips out detection, and tension grip the side wires and thus _ the steel strip per- the skin in any position. To remove’ mits using a box ed pelt, it is only necessary to com- with less timber in it, hence a saving in he side wires. material cost and transportation charges.

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POPULAR Huge Soldier’s Cap Atop Striped Pole Which Marks the Entrance io a Citizens’ Military Training Camp Established in Russia SOLDIER’S CAP MARKS ENTRANCE TO MILITARY CAMP To observe the anniversary of the com- munist revolution in Russia, a training camp rally recently was held at Moscow. Entrance to the military camp was marked by a huge placed atop a striped pole about which was fastened a rustic In the camp, citizens were put through a strenuous period of mili- tary drill and maneuvers officer's cap seat. CRAFT TO TRAVEL OCEAN FLOOR UTILIZES RUBBER SHIELDS For use in studying the bottom of the ocean, a craft invented by a Croatian en- gineer, is said to permit as many as six persons to descend at one time to much greater depths than heretofore possible and is so arranged that drawing and pho- tography may be executed while the ob- servers are on the sea bottom. One of MECHANIC the special features of apparatus is an arrat ment of rubber shi which resist and a means of movenm: as they admit air water at one side of craft and expel it at other. Ina trial, two d were lowered inside of the diving chamb: and kept there for twe hours. When they were removed, it was found t they had suffered no ill ei exztre pressures also aff fects and the air in was almost as fresh was when the appar The in tor points out that principle could be adapt to the construction of that and depths much greater was lowered. marines could scend operate those reached by pre types of underwater c: The rubber shields are such a texture that resist external forces as explosions. In a ce onstration, a quantity of explosive set off under the craft while it was merged but it did no damage. Besi “making” its own air, the apparatu fitted with powerful reflectors which mit an extensive view over the sea fl PORTABLE BOAT CARRIED IN CAR INFLATED BY EXHAUST To save campers the expense of ing or hiring a boat, a portable pneum craft has been made in England to be c ried on the running board or lugg Portable Pneumatic Boat Carried in the Auto and flated from the Exhaust of the Car

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AR POPULAR boat in- from the exhaust the auto. The may be n three minutes and is large enough to carry When stored it packs in a bag smaller It is propelled e car persons for carry- vevet, ordinary suitcase, mall motor at a speed of fifteen in hour. and mav also be used, when ted, as a bed, or turned upside down iving board RIGID CHAIRS ARE NESTED TO ECONOMIZE SPACE chairs, so constructed that they ed together, give all the space- without he and shape. and eatures of folding chairs ( idvantages or weak ness » seat Irame con- he front, while the higher than the level by having this more ] + +1 thicker a ne front. By a dozen or each taking about two r space inches ol and he floor on its resting They built in eys. may be period or + > with Vi¢ Witil any backs and legs. If a seat pad is used, it is lifted up against the back of the chair the are nested. chairs when PLANTS TREATED WITH RADIUM TO CREATE NEW TYPES exposing plants to radium, scientists =tate hope to produce varieties of tomatoes and other prod- The radium, lles, it is expected, w wa college imbedded in small ill affect the plant in such a way that new, permanent of produce will result and impor- facts may be learned as to the rela- hips between existing varieties. More $8,000 worth of radium has been wed in order to carry out the ex- ents. MECHANICS L ae J Miniature Gas Engine for Operating Model Planes or Boats; It Comes Ready for Assembling SMALL GAS ENGINE OPERATES MODEL PLANE OR BOAT For operating model aircratt or racing boats, a model gasoline engine which de velops up to one-fourth horsepower } may be obtained complete by the model builde and assembled from detailed drawings to fit the apparatus for which it is to be used It is a single-cylinder two-cycle engine weighing only two pounds and at 1,500 to 3,000 revolutions per minute ~~ The model is air or water-cooled, and all running the parts come ready for assembling PRESS FOR THE TENNIS RACKET EXERTS EVEN PRESSURE lo keep the tennis racket in condition, a lightweight press is available that can be carried in posi- tion on the racket the racket cover. A _ locking clamps implement in po- sition, an inside lever the even pressure being ex- erted at each of four contact points that are located above the racket rim

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POPULAR MECHANICS _—_—_— ASTRONOMERS’ “BIG BERTHA” BRINGS STARS NEARER An Astronomer Studying Models of the Stars and Their Patt around the Sun Above, Heavy Steel Girders Which Support the 130-Ton Tel- escope and Its Base, in Opera- tion near Berlin, and, at Right, Another View of the Huge In- strument, Showing One of the Big Gears General View of the Big Telescope; Its Lenses Are Focused and Moved Electri- cally; Observations Are Made in the Open; in Case of Storms, a Canvas Roof Is Quickly Erected; Note the Huge Counterweights at Either Side

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POPULAR MECHANICS sEAGOING GARDENS SUPPLY FLOWERS ON LINERS eardens have ot the liner. and gardener =* orchids and for the es tilled otic plant 5 vines, 1.000 nd upply fres for the passen roughout a \ Brush Cutter, Fog is the worst of the flowers, for when salt water ot salt on the wither and les it leaves a Coat dal d delicate blossoms gardeners select their plants in Certain rhododen- stand the ~ ‘ign and home ports. 7 plants, including lrangeas and azaleas, travel \ erv W ell TOOL BOX, BENCH AND LADDER CONTAINED IN SUITCASE eral pieces of furniture that are about home or workshop are con- in a single unit, which, in one form, as a carry- se, thus mak- he unit com portable. forms. and irious se may be d into a tool workbench, idder or chair. ipdoor in the easy ac- to the tools may be fas- to the step- to form the m of the chair ves OV Operated by a Tractor, Used for Clearing ; Forest; It Cuts a Swath Eight Feet Wide BRUSH CUTTER RUN BY TRACTOR CLEARS NEW LAND Hundreds of acres of brus!] have been cleared Irom ney a brush cutter The cutter trees British Columbia with erated in of a tractor. consists of a V-shaped plow, the part of which projects about six inches lower and is equipped with a cutting edge. Tl cutter clears a furrow eight feet wi pushed through the brush, whicl to Wooden timbers the plow operator falling cutter rown either side. etween and the pro nian on the tractor from Trees | he also is used to ad in blazing through Vantage a trail forest for roads. é Popular Mechan Magazine does the of the maker sae not publish name or seller of any de- vice described in its but this in formation is kept on file and may be obtained free from pages, first step of Ider Single Unit Which Can Bench or Ladder, our Bureau of In- Be Converted into Tool Box, : . formation or Folded for Carrying

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POPULAR MECHANICS for 250 years, but at the end that time, wise men of the fut will know the the than can learned by living men. Metal ceptacles, shaped like shells containing records as to the e> time, location and depth of t burial, are being deposited in more about of ice masses rious glaciers, near their ed Copies of the data are placed the safe of the Swiss Academ Science with instructions that shells are not to be removed wu: the year 2180, when their locat will be compared with the o inal place of deposit and speed of the glaciers will thu computed. “CORNERSTONE” OF HUGE AIRSHIP RAISED INTO PLACE Laying the “cornerstone’ dirigible consists in hoisting position a circle of metal con Mirror Which Plays a Large Part in Arousing Interest of Pupils in a Children’s Gymnastic School in Berlin CHILDREN’S GYMNASTIC SCHOOL FITTED WITH MIRRORS Mirrors play a large part in a gymnastic school for children in Berlin. tution is open to children Che insti- rang- ing the master ring. Whiet navy airship “ZRS-4” was st at the dirigible dock of the G vear Zeppelin corporation, at Akt mammoth 133-foot master ring was 1 To this member wili be attached the 1 girders extending to other rings aerial giant begins to take form. ing from one to five years of age, and the large mirrors are placed before the horizontal other apparatus youthful and the observe themselves and thus awaken their interest in the manner in which their exercises are performed. bars to allow gymnasts to GLACIERS’ SPEED TOLD BY METAL SHELLS BURIED IN ICE How fast does a glacier move? Only a short distance each year, present measurements reveal, but Swiss scientists, intent upon more accurate answers to the question, | have started a series of experi- ments that will not be completed Hoisting into Position the 133-Foot Master Ring Which C tutes the “Cornerstone” for a New Navy Airship

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Taking Photographs and Making Observations near Big Berg Which Drifted to East Side of Zay of Whales and Lodged near _ Barrier; Below, Admiral Byrd in His Room at the Base Camp, Studying Plans for the Exploratior paign While His } Dog “Igloo” L

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POPULAR MECHANICS Flying over the Queen Maude Range in the Ant- arctic on the Aerial Trip to the South Pole; the Broad Wing of the Plane Fills the Top of the Photograph; Be low, Remarkable “Snap” of Two Whales Rising in a Crack in the Bay Ice; Because of the Narrowness of the Fissure, They Had to Rise at an Unusual Angle

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POPULAR MECHANICS the “Snowmobile,” a ipped Tractor Which loned Eighty Miles he Base; the Expedition Fur- Demonstrated the Remark- e Effic cy of Various Kinds ~ : Mechanical Equipment

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POPULAR MECHANICS Testing a Radio Direc- tion Finder and, in Cir- cle, Bernt Balchen, Chief Pilot of the Plane on Its Flights over the Pole and through Antarctic Skies, and Who Was with Byrd on His Flight over the Atlantic; during Practi- cally Every Moment of the Antarctic Expedition Constant Communication Was Maintained with Civilization by Radio A Group of Emperor Penguins Captured for Presentation to Museums in the United States; These Birds Weigh from Sixty to Seventy Pounds Each

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POPULAR MECHANICS Circle, Dr. Dana Coman, Who Was a ite in the French Army for More Than e Years during the World War, Grew Beard That Proved to Be One of the ers of the Expedition; at Right, Carl sen, Radio Operator in the Radio Room e Contact Was Maintained with the le World throughout the Long Months e Antarctic; Below, Making a House to Hold the Stacks of Supplies the Background; Great Care Was in the Selection of the Materials for Expedition and Sufficient Quantities Taken to Last a Long Time; a Spe- pply Ship, the “C. A. Larsen,” Was red and Sailed from Los Angeles with | Byrd to Join the Flagship, the New York,” at Duned New Zea- This Point, the Fi Voyage the Antarctic Was Begun; among Other Things Not Usually Asso- with a Voyage of Adventure Were Musical Instruments and a Large Help Entertain the Men of the Expedition during Idle Hours

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POPULAR MECHANICS Digging Out the Metal Plane after a Heavy Snow, and, Below, View of Pressure Ice Such as Was Encountered in Great Masses in the Bay of Whales; Ice Piles Like These Made Sledge Travel Slow and Dan- gerous; the Base Camp Was Established on the Bay of Whales and Served as the “Capital” of the Expedition with Its Liv- ing Quarters, Radio and Weather Stations, and Airplane Base; Little America Was Begun in December, 1928, and Byrd and His Men Lived There till February, 1930

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POPULAR MECHANICS | 7 af > peel > “t ie > - Warming Up the Engines of the Tri-Motored Ford Plane, the ‘“‘Floyd Bennett,”” Which Carried Admiral Byrd and Companions over the South Pole; at Left, Captain Parker Standing in Hole Cut in Ice to Receive Water from the Photographic Laboratory, and, Below, Joe Rucker, Movie Cameraman, Making Film to Show Some of the Prize Beards Grown by Members of the Expedition; Boxing and Other Athletic Contests, Amateur Theatricals, Even to Revue, the “Antarctic Follies,’ Lightened the Hours When the Men Were Confined to Camp by the Storms and Snows of the Far South

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POPULAR MECHANICS Above, Airplane View of “Pan- cake” Ice Floating in the Ross Sea; at Left, What the Well- Dressed Antarctic Explorer Wore—a Face Protector, Made like a Baseball Mask and Cov- ered with Wind-Proof Material; Below, More Pressure Ice Piled in Jagged Heaps in the Bay of Whales Not Far from the Base Camp

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POPULAR MECHANICS ‘ A Conference of Pi- lots before the Flight over the South Pole; from Left to Right, Dean Smith, Capt. A N. Parker, Admiral Byrd, Bernt Balchen and Harold I. June; Below, George Ten- nant, Cook, with a Captured Penquin ; These Birds Were Curious and Tame But Not Satisfactory as Food re Below, Adm. Byrd Making Observations at Little America; he Flight over the South Pole Was But One of the Inter- ting and Important Accomplishments of the Expedition ; usands of Square Miles of Territory Were Surveyed and M Mountain Ranges and Other Geographical Features Were Located and Mapped; on One of the Geological Trips, Members of the Byrd Expedition Found a Cairn Built by the Late Roald Amundsen in 1912 While on His Way Back the South Pole; on Another Trip, a 150-Mile Gale Wrecked One of the Airplanes

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POPULAR MECHANICS Night View of the Adolph S. Ochs Ra- dio Station Towers, Looming above the Ice Huts at Little America; the Night Lasted Four Months, Giving the Men Am- ple Time to Prepare for the Rigorous Trips Which Were to Fol- low in the Spring The “City of New York,” Flagship of the Expedi- tion, Lying in Discovery Inlet at the Edge of the Ice Barrier around the Antarctic Continent; the Bundles on the Rigging Are Filled with Whale Meat; Shortly After This Photograph Was Taken, the Ice Broke Up

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POPULAR MECHANICS the Base Camp, a w Members of the pedition Enjoying a ume of Cards While eir Companions Look from a Bunk; in rcle, Dean Smith, and Harold June, Barbering View of the Mess Hall Shortly Before Supplies Had Been Stowed Down for the Winter; the Flag Was Kept Flying as Long as the Sun Shone; Materials Were Car- ried by Dog and Tractor-Drawn Sledges from the Expedition Ship, the “City of New York”

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236 POPULAR MECHANICS Running the “Snowmobile” Out of Its Winter Resting Place; It Was Completely Hidden by Snow and Ice When Spring Made Further Trips Possible; at Right, Howard Mason, Radio Operator, Who Was with Wilkins on Two Alaskan Trips , Jacky fh at te View from the “City of New York” Showing Dog Teams | Loaded for Start to Base Camp

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POPULAR MECHANICS ne” Haines with One of Admiral Byrd’s Expedition Was sig Box Kites Used in Mak- : the Most Completely Equipped Weather Observations, and, . Scientifically of Any That Ever Oval, Jim Feury, Driver of Penetrated the Southern Re- Snowmobile,” Smiling after gions; the Weather and Other Windy Trip through Flying Data Obtained, It Is Expected, Clouds of Snow Will Be of Inestimable Value “Floyd Bennett” Being aided with Skis, Snowshoes 1 Other Things Likely to Be leeded in a Forced Landing

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POPULAR MECHANICS At Left, Capt. Ashley McKinley Sights Huge Aerial Camera on Human Tripod, and, in Oval, Anothe: View of the Photographer and His Mighty Camera embers of the Expedition Sa- luting the Flag, When It Was Raised the Day the Sun Re- turned after the Long Night at Little America

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POPULAR MECHANICS

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3el yw, the Tri-Mo- tored Plane “Floyd Bennett,’’ Being Loaded with Gasoline and Other Supplies for the Flight over the South Pole; Byrd’s Expedi- tion Was a Special Vic- tory for Aviation as fell as for Science, Skill and Courage POPULAR MECHANICS Left, Admiral Byrd at the Right, Watch- ing Chris Braathem Completing Model of the “City of New York”; Below, Rid ing on Sleds behind the ‘‘Snowmobile,”’ Left to Right, G Hamilton Black, 7 Feury, Dean and Paul Siple

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POPULAR (ELLTALE VAPOR OF PLANES TURNED INTO WATER \rmy air-corps officials recently have devoting considerable attention to of vapor noticed in the wake of pur- planes during maneuvers. This phe- enon was particularly pronounced ng high-altitude flights of about 28,000 low temperatures and rarefied air, was found to be the result of conden- moisture from exhausts. The ik of vapor looks like the trail left by writing plane, and has been studied 1use such a streak, when multiplied by presence of an entire squadron, ren- n of the ships easily visible to anti-aircraft ries on the ground and enemy planes he sky. The remedy, however, was ind to be quite simple—the installation ‘ondensers on exhaust lines, similar to e in use on motors of dirigibles. SINGLE-WHEELED AFRICAN TAXI RUN BY MAN POWER \ Vhile the automobile is used in the ire developed parts of Angola, west the bush chair answers for taxi rvice in the more remote districts acces- e only by rough trails. This vehicle, ts more luxurious form, consists of a tbber-tired \trica, which is unted a light frame with a spring seat wire wheel on for the passenger directly over the wheel. Shafts fore and aft are for the two na- es who propel the conveyance, one pull- ind the other pushing. Single-Wheeled Bush Chair with Double Shafts Used for Taxi Service in Parts of Africa Served Only by Rough Trails MECHANICS Cage Antenna for Ultra-Short-Wave Radio a Berlin Engineer Has Used for Transmission of Fog Signals ULTRA-SHORT RADIO WAVES GUIDE SHIPS IN FOG Fog signals, ultra-short radio waves of twenty to 100 centimeters, would be more effective than lights, a 3erlin engineer concludes after a series of experiments. broadcast on The waves are readily concentrated in searchlight fashion, pene with but absorption; they trating mists little are of short range, re quire but little transmit ting energy and are im mune to atmospheric in fluences such as rain, snow and other factors that limit the usefulness of overhead conductors The engineer believes that might also be adapted to the use of po they lice and fire-department units and where long dis- tances are to be covered, a series of relay stations being used.

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242 POPULAR MECHANICS DIRIGIBLE GRABS MAIL BAG FROM SPEEDING TRAIN |] tempts. It was fou | however, that the be: ing of atmospheric c ditions on dependa! operation makes it u likely that such a serv can be operated on schedule basis. The oy erator of the blimp difficulty in maintaining his ship on an even kes directly above the tra while cruising at fifty-fi miles an hour as the tr below proceeded at thirt When the diri ble was brought into p sition, its nose was tippe downward, and neously the two miles. simulta- fishet men made a grab at the sack with their hool The dirigible dropped t mail to a ship. MOTOR CARRIED ON BACK RUNS TOOLS Muscular power Dirigible Taking Mail from Top of Moving Train with Grappling Hooks, Preparatory to Transferring the Pouch to a Ship at Sea Transferring mail from a speeding train to a moving dirigible was successfully ac complished in recent tests near the naval air base at-Lakehurst, N. J., to determine if it is feasible for an air carrier to take the mail from a train in motion and then transfer the pouch to a ship at sea. In the dirigible-train experiment, a portable platform was erected on the roof of the last coach of the train. Between two up- right posts, holding the platform in posi- tion, was suspended a_ rubberized supporting the mail sack. The rope was tied to the posts in such manner as to be easily released by contact. rope Two men in the gondola of the dirigible carried long ropes to which were attached four- pronged grappling hooks. The men fished tor the bag when the dirigible was brought in position over the train, finally making the pick-up after several unsuccessful at- hand too such as hedge trimmet and borers, is placed by a small electric motor worn the back, which recently was tested su cessfully in Germany. The little mot provides sufficient energy to operate nea! any ordinary carpenter or garden tool. operating Saws Electric Motor, Worn on Back, Provides Power Operating Small Garden or Hand Tools

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idget Cars Next < ~~ 2 — a A -_ ~ —_ nglish Austin Tuned Up and Streamlined for Racing; It Hung Up a Class Lap Record of 63.62 Miles per Hour in a Tourist Race Held in Ireland i INTRODUCTION of midget cars this country is a development which ng watched with intense interest by hody—the public in general and otive experts in particular. ers are intrigued by the thought that a car may be available which will little or nothing to maintain and 1 can be bought for the small sum of or perhaps less, fully equipped and | with a good-looking body. th the ability to run forty miles or on a gallon of fuel, having small probably twenty-six by three and tenths), which cost only a few dollars, possessing such small parts that re- expenses must be accordingly low, it ir that all those who are interested ximum economy will give such cars losest consideration. llowing the growing popularity of ‘t cars in Europe, executives of ican automobile companies have, x the past few years, given consid- thought to such cars and to the ble demand there might be for them country. One large company, at designed and built several cars of pe tor experimental purposes. But ry case there was one fundamental question which troubled them: Will the American public buy these cars in sufh- cient quantity to make the venture worth while? In this connection, it is interesting to note that years ago a number of midget cars were built in the United States and two of them were conspicuously success ful, namely the first popular-priced four- cylinder Ford (1906) and the first Hup mobile (1909)—also a four. The Hupmo- bile and the Ford classed as midget cars with respect to wheelbase and weight, al though their engines were considerably larger than any of the midget cars now built in Europe. The Hupmobile had a wheelbase of eighty-six inches, and a pis ton displacement of 112 cubic inches with cylinders of three-and-one-fourth-inch bore and a three-and-three-eighths-inch stroke. Originally it was built only as a roadster and sold for $750. The Ford had a wheelbase of eighty-four inches, weighed 700 pounds, and possessed an engine of three-and-three-fourths-inch bore by three-and-one-fourth-inch stroke, giving a piston displacement of 143.5 cubic inches. Its price was $500 and there was only a roadster model. Both cars were satisfactory according to the standards 243 3

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244 POPULAR MECHANICS Courtesy Agence Rol The Rosengart Five-Horsepower Roadster, a French Version of the British Austin; Note the Thin Shell Radiator of that day, but as the years rolled by they were enlarged, principally, it is be- lieved, to permit the fitting of five-pas- senger bodies. By comparison, the English Austin has a wheelbase of seventy-five inches, a four- cylinder engine with a bore and stroke of two and two-tenths by three inches, a tv-one to sixty cu inches and with wl bases varying from enty-five to 108 inc Weights of these « average about 1 pounds. With nearly a score midget cars in Eur the reader is certair ask, why these cars so popular across ocean. Speaking of p: ularity, the Austin is largest production job England, and because its success, it is manufactured as Rosengart in France and the Dixi in Ger many—and, as already noted, the car, with greatly improved appearance scheduled to go into production in country. The wide use of midget cars in Eur is due to several things: the greater of producti mn in Europe; oppressive heavy vV motor- taxes; high cost fuel: lower wage and high cost of in ance—in some cast Due apparently the less effective duction method Europe, in order build a car to sel $500 to $1,000. it is piston displacement of forty-five cubic inches, and a weight of about 1000 pounds. The term midget car, of course, is relative, But if it is assumed that any modern car with a piston displacement of sixty cubic inches or less may be so classed, then there are sixteen European midgets, with piston displacements ranging all the way from twen- Another Midget-Racer Type and an English Austin Four-Passenger Model Seven-Horsepower Motor; Note the Wide Door

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POPULAR MECHANICS to cut the size down as compared \merican standards, even if this difficulty e removed com- ely, midget cars | still be in great nd because of the ituation. In Eng- for example,. the vy tax is $2.55 for ¢ is of the Tiny English Austin, and Interior of the Four-Passenger Coupe quare inch of area for all the pis- in the engine. Thus the yearly tax model-A Ford is $120, whereas the on a car as small as the Austin is a less than $39, a yearly saving of $80 taxing alone, ww let us examine the midget car e closely from the standpoint of driver passengers. To begin with, there is room for a comfortable two- enger body on these short-wheelbase juate leg room, for instance, may be nor- Also, there may be space to seat children and an adult behind the t seats, and in emergency two adults find accommodation there. Riding ty is generally conceded to be satis- iximum speed. may be forty to fifty per hour, or more in some cases. e midget engines are necessarily ind the power they develop is mod- say, ten horsepower, the wind re- e is also low, and it is this factor which particularly affects maximum speed, STCLP a}&t ha ecil Call es 1 Is reason- t at, at W T a l speeds, fuel consumption depends on car ably accurate to say weight and engine size, and particularly on car weight. Thus it should be obvious that a car weighing 1,000 pounds should run twice as far on a gallon of fuel as one weighing 2,000 pounds or more. Other things being equal, a 1,000-pound car should steer about twice as easy as a 2,000-pound car, and the same ratio may be approximately applied to foot pressure shift ing should be much easier, because of the 1 comparative lightness of the clutch required on clutch and brake. Gear mech anism and the gears which rotate with it In short, a midget car should handle with incomparable ease, a thing which will ap pealto many. Finally, its short wheelbase permits it to be maneuvered and parked in places denied to larger cars. MOTOR CUTTER MAKES LETTERS WITH BEVELED EDGES Letters, fancy designs and stencils are cut from a wide variety of materials with a motor-driven unit that has five different cutters and an attachment on paper, practi- cally all kinds of synthetic lumber and thin metals as well as wood. for making bev- eled edges. The | | machine operates | | L 3

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246 POPULAR BALANCING THE PROPELLERS OF AN OCEAN GIANT MECHANICS Courtesy Marine Engi Upper Left, Making Guide Lines on Propeller Blades for Chippers to Follow; Right, Boring Taper Hole Hub of One-Piece Propeller; Lower Left, Testing for Static Balance Special attention is given to the correct balancing of the propellers on battleships and other craft, for on their accuracy de- pends, in a large measure, the steadiness of the vessel, an important factor during gun fire. propellers are important to commercial ships where safety, steadiness and a minimum of vi- bration are imperative. At the navy yard, the big propellers’ balance is carefully checked both while they are sta- tionary and while revolving, although the latter method has been found impractical on the largest wheels, as they cannot be rotated sufficiently fast Balanced also 3oston without the in- stallation of huge and costly electric mo- tors to furnish the power. In most cases, errors in the balance are due to unequal thickness of the blades or to unequal lo- cation of the blade centers around the hub. In a three-bladed propeller, for in- stance, the axes should be 120 degrees apart, but an off-center displacement of one degree would impose an_ une strain on the propeller, which would causé vibrations and possibly breakage. balance a huge propeller for the “Le, than,” it was necessary to remove e's pounds of metal from one blade and pounds from another. The blades had to be ground smooth and reheated TEN THOUSAND MILES SAILED FOR A FISH Owing to improvement in portabl frigeration plants, better design of d« sea fishing craft and improved const tion of fuel-oil tanks to permit a cru range of 10,000 miles or more, the fleet of San Diege and San Pedro, | is this year voyaging 5,000 miles so ward along the coast of Mexico and tral America in search of fish weig! from fifty to 350 pounds each. Now not unusual for a boat to make a t1

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POPULAR 8.000 to 10,000 miles and return with below-decks refrigerators filled with ons or more of fish worth six cents und to the fisherman. The boats 1 yacht’s bow, a freighter’s midship n and a tug’s low, flat stern, and are 120 feet long. They carry 100 tons e sardines in tanks on the stern, and refrigerating plant keeps 125 to 175 of fish in perfect condition. Diesel nes drive the craft and fuel-oil tanks 1 two months’ supply. While the tuna fish have always been found off ‘pical coasts, fishing boats until re- were unable to bring them back in condition from distances greater 1,000 miles from the packing plants. ‘tine whalers, these boats make the fishing vovages in the world. BICYCLE WITH GLIDER WINGS GIVES THRILL OF FLYING sme of the thrills of flying have been ined by the owner of a bicycle who equipped his vehicle with a set of and a tail. The lift on the wings e down pressure on the tail combine the front wheel when the machine 1 tt forward motion, the rear wheel re- ing on the ground for traction. Lat- control of the wings is combined with control of the front wheel, and the ar- ngement of the tail keeps the wheel at iniform height above the ground. ngs and tail are quickly detached when- the rider wants to use the bicycle in rdinary way. MECHANICS Auto Containing Equipment for Locating Source of Radio Interference; Note the Rod Antenna RADIO TROUBLE HUNTER IN CAR ENDS INTERFERENCE Finding causes of radio interference on power lines is simplified with a portable locator which can be operated from an automobile OI! carried about suspected points suspended from the shoulder. The trouble hunter consists of a four-tube combination radio and audio instrument, self-contained with A and B-batteries, an ordinary headset, a loop with socket for the ceil ing of the auto, a smaller loop for use outside the vehicle, a base if the loop is to be used in the ord nary manner, and a rod antenna in four sections for attachment to the roof of the car. One man in an auto is able to pa trol suspected lines and locate extremely § slight leaks or noiwe sources @Canned salmon con le Equipped with Glider Wings and a Tail; the Wings Lift the Front Wheels off the Ground When the Wheel Is in Motion tains a substance which prevents pellagra

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POPULAR MECHANICS Racing Car Speeding around the Almost Perpendicular Wall of a Motordrome Track with an Unleashed Lion Cub as a Passenger RACING CAR CARRIES LION CUB AS EXTRA PASSENGER Driving at eighty miles an hour around the almost perpendicular wall of a motor- drome track with an unleashed lion as a passenger is one auto racer’s idea of af fording an extra thrill for spectators. The driver takes as an added passenger a five- months-old lion cub which crouches in a frame built on the side of the car. The most difficult part of the remarkable stunt is to induce the remain quiet throughout the wild ride, as a move on the part of the animal might be disastrous to both occupants of the car. lion to SCREWS ARE HELD IN GLASS BY FIBER PLUG Plugs made from stiffened jute fiber in various sizes and lengths now are avail- able for fastening screws in any kind of material, including glass, metal or plaster. When the screw enters the plug, the jute fiber expands in all directions, compress- ing against the sides of the hole in the metal or glass. The hole, plug and screw diameter are the same, thus threading the plug automatically whe the screw is inserted, an permitting removal a1 replacement of the scre\ The hole for the plug glass or tile is first mad with a star or twist dri The plugs make it w necessary to tap holes metal, tile, f screws, and thus preve chipping the materials glass or STENCIL TRACING IS MADE EASY BY FRAME Tracing pictures, draw ings, music or display let tering on dry stencils f« reproduction on a dup! cating machine is simp! fied with a stencil-tracing frame containing a lig underneath to make drawing easy. It consist of two pieces of framed three-quarters of an inc apart, with openings at top and air hole the bottom to create a draft, thus prote ing the celluloid writing plate and ste from the heat of the electric light b« neath the lower glass plate. A metal cri plate at the top permits insertion of a1 form of stencil-backing sheet in any de about glass, sired position, and the frame may be ad justed to any desired angle. Spring-wire clamp gauges are provided for holding letter and numeral strips in position. Stencil-Tracing Frame Consisting of Two Plates Glass with a Light Bulb Beneath Them

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POPULAR MECHANICS GAR PRODUCED FROM MILK USED IN MAKING CANDY iccessful experiments by the depart- of agriculture with milk sugar and sirup in making candy, presage the ng of a new door for utilization of urplus of these agricultural products. ugar, technically known as lactose, unts for about five per cent of the ht of whole milk, and at present is iced commercially in limited quan- only. It is obtained from milk whey, until the recent discovery of a new ess for extracting it, has had a high cost. Its successful use in ng candy, along with utilization of sirup for the purpose, may e a market for all the surplus of both ucts. Experiments being lucted in the use of honey for candy, ticularly to determine some method h will prevent it from turning dark n heated, and to find whether all kinds ney have this tendency. luction same also are ROTARY PAINT STRIPER ROLLS LINES ON AUTOMOBILES Painting deco- rative striping on automobiles may now be done quickly and easily by the novice with a rotary striper, a precision tool con- sisting essentially of a wheel, revolv- ing in striping which color, or material, rolls the stripes in any de- The apparatus is equipped 1 trigger which automatically starts luts off the flow of color, and an ad- ble guide which can be set in any tion to follow beads, molding, win- or door edges. Guides of different es and wheels in different widths give ety ot patterns.

| pattern. < 1 } i ne of the navy’s first wrought-iron the “Wolverine,” launched eighty- years ng ship. ago, still is in service as a Ancient Astrolabe, Superseded by Sextant, for Computing Lati- tude and Longitude ASTROLABE TELLS TIME OF DAY AND POSITION FROM SUN Latitude, all are told accurately by peering at sun through an longitude and the time of ancient astrolabe, now the Adler planetarium at Chi cago. The instrument, made in England in 1500 and still workable, was used for observing the position of heavenly bodies quite generally until it superseded by the sextant for computing latitude and longitude. owned by was NEW WAY TO RESEAT VALVES SAVES MUCH TIME Renewing valve seats has been greatly, simplified by a system recently patented cutting the old one and undercutting the bottom of the recess thus formed. The seating is formed by away Into the recess is pressed a collar , of cast iron, around whose base is a rim pro- jecting downward which is forced into the undercut portion. The ring is thus prevented and seat is cut around the top edge from moving, a new at ae ee : In this manner all valve seats can be renewed in a few hours.

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By KENNETH B, MURRAY ‘yO YOU have a little “jinx” in your home—do you knock on wood or hang a horseshoe over the door? Well, you needn't feel exclusive, because every- body does it, although few know why they are doing it. Let’s go back several thousand years in imagination to ancient Egypt. The priests wrote: “Death and calamity to anyone who dares despoil the royal grave, or re- move from it the precious stones and metal.” This kept the superstitious na tives away but left the priests to plunder at their leisure. Evidence of this has been found in a number of graves opened by expeditions from the British Museum. The tombs were found intact and undis- turbed as they had been at the day of burial but inside there was indisputable evidence that the priests had been there first, and all that was left for the excava tors of the present day was a dry mummy. In the year 1889, five members of the British Museum staff located and opened, in the Valley of the Kings, the sarcopha- gus of one Priestess Amen-Ra. After- ward all five of the party died at natural intervals. Also, the men who transported the mummy to England, the official pho- tographer, the translator, and a servant in the museum employ, met with various 250 An Ancient and a Modern Talismar of Good Luck; during the Thirteent} Century the “Lee Penny,” the Medica Token Illustrated at the Left, Was Be lieved to Have Magic Curative Prop erties and Was Widely Used by the Af flicted; Below, the Person Who Finds a Horseshoe, Even in This Age of Auto mobiles and Airplanes, Still Is Consid ered Lucky, and This Superstition Prob ably Arose Because the Shoe Is Shape Like the Doors of Homes That Wer: Built Thousands of Years Ago disasters and accidents. In the natu order of things this would pass as not! unusual, but some superstitious folk se on the incidents as a result of the cu So when King Tut’s tomb was discover: the precedent was remembered and credulous searched for incidents that c be taken for disasters in the lives of n bers of the party. They would have | just as successful had they chose watch for calamities in the l*ves ot other public men. Do you knock on wood, and know you do so? Are you superstitious of number thirteen and Fridays? Do believe that a horseshoe or crossing fingers maintains and brings you luck”? Many of these superstitions have

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from Biblical times. Knocking on became a superstition when an an- conceived the similarity between it knocking on the Cross (of wood). e cross their fingers for the very same Others believe that the number teen is unlucky because that number at the Last Supper and the first to was crucified. Friday was the day he Crucifixion. ese are incidents Christian his- but why any- hould seize on as signs of luck” is not years, steamships ly understood never set out on ° a ing no basis in H F RE vovage on Friday if : ¢ is labeled a In various coun- perstition, mean | | FS tries of Europe, the something that unlucky day is des ve do not under ~ ignated as Monday d, or on which or Friday, accord lack education. . ing to the country Until recent F ¢ Several years ago an Englishman came to our shores and was surprised to learn that Friday as our hoodoo day. His was Mon day. He finally com promised on setting aside both Monday and Friday as days on which to be espe cially careful. Steamships, hotels and Pullmans have difficulty in getting customers to over- look the number thirteen on room, con partment and car doors. Recently the state of California announced that it wa swamped with requests trom prospective auto-license purchasers not to plates bearing the number other hand, thirteen men in formed the Thirteen club, an thirteenth of each month A courageous bit of daring when there on Auto-License Plate; Skull Used in Mystic so much “bad luck” floating al nd Ancient Hebrew Talisman, Supposed to TI , ] : ar , it Bring Success in Business rae Ge Fears SEe Ws

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POPULAR Friday the Thirteenth, Considered Doubly Unlucky Because Thirteen Were Seated at the Last Supper, and Friday Was the Day of Crucifixion gious practice to paint the doorways of each house with the blood of sheep. The doorways were all arched. Gradually the practice came to be a means of keeping “bad spirits” Ther the similarity between the shape of the door Thereafter out of the house. and a horseshoe was noticed. horseshoes became “lucky.” Astronomy iS that has seized, the sciences of being a pseudo-science, for the pur- of burden but suffered one the as poses of astrology. The heavens were di- vided into twelve parts, each with a par- ticular “ by a sign.” Each sign is represented To be born in the month covered by the sign of the lion, one different meaning. will surely be courageous in life, so And to be born un- der the sign of the crab is to be backward, in the manner in which the crab travels. The only difficulty presented is that, in fortune telling by astrology, the informa- the astrologers say. tion given is a generalization designed to cover most any person. In the manner, for same the moon comes part in a number of supersti- Perceiving that the moon exerts a certain drawing power on the earth, in that it causes tides, the superstitious find 1ts in tions. MECHANICS the new moon a most propitious time planting, so that “as the moon grows size so will that which is planted.” the same reason the natives in Cuba superstitious about walking or sleey in the moonlight, believing that it will di their faces to one side while it is wax or cause depression of the features w! it is on the wane. talisman has even in our own modern life. The had its The ta man first originated through strange magic ligious beliefs, but the vears and addit of ideas of each generation have cont: uted their and may obtained f dues, today a talis be yr the cure of alm any disease. ELECTRIC MODEL PLANE FLIES AND LANDS ITSELF Electrically operated miniature that really fly and make three-point la ings have appeared. They are connect to a model hangar by a steel-spring Current, obtained from the lighting soc! and put through a pa through the spring rod as one side oi transformer, circuit and through a separate wire d the rod to the tip of the wings as the ot side, to operate the tiny motor and re\ the propeller. When the current is off, the ship makes a graceful three-; landing. It requires about fourteen \ to take off and is operated on app: mately eight volts. lights. | The plane has To accompany the model, a | Model Electric Plane and Hangars, Showing Fle Wire That Holds Plane as It Flies in Circ! ing field with hangars, border lights a tiny beacon with a revolving light be obtained.

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POPULAR MECHANICS ] Aerial Workshop Suspended from a Crane to Allow Workmen to Attach Clamps to Sections of a Bridge Cable; the Shop Was Complete in Every Detail with Modern Tools and Equipment BRIDGE WORKERS’ AERIAL SHOP SUSPENDED FROM CRANE ble workers on a German suspension ve recently enjoyed the novelty of an workshop. When the cables were ed to support the suspension bridge the Rhine river between Cologne and heim, it was found necessary to bind at various points with sleeves or To accomplish this task, a plat- for the workers was suspended from ne. The clamps are attached under ressure of 300 tons or that mplete with many workmen t be available, and this fact made nec- vy the workshop in the air. more, so shop GAS MANTLES ARE RADIOACTIVE mmon mantles such as ble gasoline lanterns gas used in become radio- ‘when allowed to remain unused for il years. The mantles contain a und of the metal thorium, which radioactive and does not emit pene- rays like its decomposition prod- However, when the mantle remains unused for seven or eight vears, there is formed a new compound, mesothoriun which is many times as active as sends off and invisible waves. radiun and constantly small particle SANITARY ASH-TRAY RECEIVER DISCARDED WHEN FILLED Disposing of cigar and cigaret ashes is made easy by a sanitary ash tray with a removable receptacle which is discarded filled receiver it when and a new serted in the tray The refills are in expensive and have properties which neutralize tobacco odors, hile a sliding lid in the top ot the tray smoke. is all may he top prevents The tray metal and obtained while the in various colors, is of stain less steel.

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254 POPULAR MECHANICS LIFEBOAT FOR SEAPLANE HAS SAIL AND A MOTOR in so doing, smashed turret and to away the outboard tor. An attempt to cr the Atlantic in a sim craft is planned. glass LAMP OF THREE COLORS GUARDS RAIL WORKERS Devised especially to Unsinkable Lifeboat for Aircraft Equipped with Out- board Motor and Sail; Above, Glass-Inclosed Lookout Turret Set in the Deck To enable a pilot on a transoceanic flight afloat and eventually reach shore after a crash at sea, an unsinkable “kavak,” or lifeboat for aircraft, is equipped with both a sail and two out- board motors. During a storm, the craft can be closed watertight, the occupants to remain being afforded a view in all directions from a hexagonal, glass-inclosed lookout turret set in the deck. The canoe itself carries three persons, and inside there 1s storage space for folding rubber boats which it can tow, so that more than thirty persons may be emergency. accommodated in an The craft is equipped with oars as well as sails and motors and can be steered from inside. In a test trip, the inventor made a nine-day vovage from the Faroe islands to Bergen, Norway. Off the Norwegian coast the boat encountered an eight-ton whale and was disabled, drifting helplessly for three days until fish- ermen sighted it. The whale made a dive for some refuse thrown overboard, and workers in railroad ya a carbide signal lanté now on the market has a light at the r as well as a strong white light in fro: The rear light may be changed to red « green by means of a locking device tl insures against an accidental change the color. The red light plainly tells t engineer or motorman that a man is in th yards, or it may be used to replace a ya signal out of order. ADS ARE WRITTEN IN WATER ON CITY SIDEWALKS Advertising slogans are written water on sidewalks in Barcelona, Spai: with the aid of a portable machine | inscribes the characters from a stencil rangement in a revolving drum and w container pushed along by the operat The letters are plainly visible, as the sp they occupy is left dry while the bord around them is changes color. moistened and_ het Temporary Sidewalk Sign Written in Water; the ters Are Dry, and Space about Them Is Wet Bl MO\ Cc

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BO I POPULAR MECHANICS E-DRY WALLS KEEP OUT DAMPNESS al methods of con n were employed to make a Gal- fex., hospital en- 1oisture-prool. e of its location, is damp, a building bone- and quired special treat- foundation, walls f. Membrane wa- fing, marine ce- damp-resisting plastic waterproof i dehydration so utilized. water- were 1embrane consisting ot lavers of asphalt- ted and employed from undation up to the first floor, but this was applied, the surfaces so coated ted were covered with a cold binder 1 on with air under pressure. A mpound was sprayed on the under- ill concrete beams, slabs, joists and on the ground floor, and the de- ion solution was applied to the ma- walls, inside and outside, to res of the stone and brickwork. seal MOVING BRUSHES OF DOORMAT CLEAN IT AUTOMATICALLY Sanitary door- t mats that clean themselves are equipped with mov- brushes in- the ordi- fiber that al- dirt to Che mat con a frame in which is placed a grate ich the brushes When trod brushes move alternately, causing them that shakes the e, allowing it to fall through the nd into the mat holder. Mat and in be removed to empty the dirt ils, and able stead of nary lows settle in it. rest. on between sections of the brushes eplaced when worn. Children on Horseback Engaged in Doughnut-Eating Race; the Doughnuts, Suspended from Strings, Cannot Be Touched with the Hands DOUGHNUT-EATING CONTEST FOR YOUNG RIDERS Modern variation of the Hallowe'en game of apple bobbing was provided recently at Pinehurst, N. C the mounted on engaged in-a where children, horseback, doughnut-eating contest. The doughnuts were suspended from strings and the chil dren, approaching them on their mounts, endeavored to devour the doughnuts with- out touching them with catching the their hands by rings between their teeth after moving the horses into position. TEST PLUG FOR WATER PIPES HELPS IN BACKFILLING lo determine whether sections of a water main are tight as the pipe is being laid, a test and puddle plug now is avail which trench. Che 1 also is a help in able the backfilling plug is inserted in the end of the pipe and water pressure is ap plied for testing the joints. Dirt is then dumped in the trench a feet behind few the On the to whicl end of the pipe to form a dam. test plug is a two-inch coupling a hose is connected and the trench flooded

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256 POPULAR MECHANICS Spring Tester in Position, to Record on a Penciled Graph the Riding Qualities of This Car AUTO’S RIDING QUALITY SHOWN BY SPRING TESTER Riding qualities of an automobile are accurately shown on a penciled graph by the use of a precision apparatus which automatically indicates the action of springs, shock absorbers, tires and axles. The car is placed on a smooth floor and the recorder stand is set close to the fender at the wheel to be tested, a pencil being attached to the fender by a clamp, and a graph sheet placed in position on a recording drum which the pencil touches. The car is raised to a given height by an electrically driven jack, and the jack is released suddenly after the revolving drum has been started. The drop causes the springs to compress and recover, and all vertical motions are recorded on the chart along with their duration to hun- dredths of a second. Each wheel is tested separately, then the two rear wheels si- multaneously, and the two front wheels together. The recording pencil also may be attached to the hub to give readings covering axle, tire and wheel movement, thus affording an accurate picture of the shock-absorbing qualities of the car and indicating the adjustments necessary. NO CHURNING MAKING BUTTER BY CENTRIFUGAL PROCESS Butter can be made without chu by using centrifugal equipment whic! the additional advantage of being tinuous and not coming in contact human hands. The apparatus first used for making high-grade cream of seventy to eighty per cent butter fat cut the shipping bulk of this product } about half. Modifications then were : incorporating the processes of paste zation, culturing, coloring, washing, ing and working the butter. After ob ing a high fat content, it was found t a simple process to knead the butte: dispel the buttermilk with the appa: which is to be sold at a reasonable c TUBE-FORM FIRE EXTINGUISHER FOR HOME AND AUTO Resembling an overgrown tube of ing cream, a chemical fire extingu now is available for the home or aut bile. To operate it, a cap is removed f1 the top and a hole punched in the nozzle with a pick accompanying it. Tu ing a key at the flat end forces the | through the nozzle in a fine spray. tube extinguisher costs little more t! refill for the ordinary cylindrical ki: Chemical Fire Extir guisher Operated Lik — a Tube of Shavir Crean BL MU] REM

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POPULAR MECHANICS CK RASPBERRY GROWS WILD AND RESISTS DROUTH growers are interested in a wild of black raspberry which was in the Oregon woods. It thrived a hot, dry season when domestic languished, did not die down in and even produced berries in the ll. It is believed the specimen is a of the black raspberry with some of blackberry. Its leaves and habits are much the same as of the latter. Experts are examin- e fruit to determine if it is suited to ercial shipping and canning. MULTI-COLOR AIRBRUSH PAINTS THREE SHADES AT ONCE lying one, two, three or more colors e same time previously required to one, a multi-color airbrush controls color independently so that all may ipplied simultaneously, or shut off at Perfect control is offered from the t line to the widest spray, and multi- ple heads in forty combinations pro- vide a wide coat- ing range. It may be used as a Ssin- gle unit or ex- panded into gang units of any num- ber of brushes for manual or air op- eration. Pressure feed tanks can be loyed when a greater finishing speed ired., REMEDY FOR CABBAGE DISEASE drated lime, one of the commonest cheapest chemicals, has proved an ef- e remedy for clubroot of cabbage, of the most serious diseases of this crop. While other lime neffective, hydrated lime, applied two { to the acre, keeps the disease in forms of Clubroot is caused by a primitive nism belonging to a class known as molds, a group so far down the evo- nary seale that it is uncertain whether reatures are plants or animals. — ww ~~ — Artificial Angleworms That Wriggle on the Hook Have Proved Attractive Bait ARTIFICIAL ANGLEWORM BAIT COMES BY YARD Fishermen who prefer angleworm bait, but are unable to procure them, now may use artificial worms to deceive the fish. The artificial bait comes in three-foot lengths, and the angler may cut it to whatever size he believes will best quarry. When on the hook, a remarka attract his the bait bears ble resemblance to a wriggling worm. BALER FOR OLD NEWSPAPERS SIMPLIFIES TYING newspapers are Old easily baled and tied in a simple rack that keeps them in a neat pile and is so adjusted that the strings are al-. ae” 4 ready in place as p the bundle is built ba up, thus saving the work of dling a cumber- and heavy pile when the pa- han- some pers are ready for disposal. The baler is strong and neat, easily last indefinitely. } a A moved about and will

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(Qpger the Battling through a Thunderstorm; Vicious Wind Currents and Not So Much Lightning Constitute the Ch Worry Here, and Wise Pilots Always Try to Avoid a Storm Area of This Kind

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2 ah ee ee che Se ® eae = aed iT Vade S<7 ae ace dh a » a 1 t: nes Oe * 5. , ee + eensboro Bridge Looming Up through Clouds That Shroud Most of New York City; a Hole in the Fog like This Is Always a Welcome Sight to the Pilot Seeking a Landing By JAMES W. BOOTH ) LOVERS of outdoors the tains between Bellefonte and Aarons- Pa., are numbered among the mas- pieces of nature, but pilots of the air christened them the “Hell ‘tch,” for. they are a barrier that marks most treacherous flying conditions to und anywhere in the United States. till, day and night, over that stretch, mail and ress, plow along. A corps of the most rt’ pilots in the country—and the daring—is on the job to see to it that mail goes through moun- have 1 ly loaded planes, bearing he percentage of fatal forced landings ashes, to be sure, is small compared the total number of such landings accidents, and in the repair base at cago, they can show you hundreds of and twisted propellers from that have made bad landings or dif- take-offs without fatal results All steel of which points to one fact, aviation men say: The odds are heavily in favor of the pilot going through, and of his living ina crack-up even if it occurs along the Hell Stretch. The question may arise, why Pennsyl- vania’s mountains are so treacherous? Why are they regarded as the worst coun- try in the United States to fly over? It is because these mountains are unlike any others in the land. traordinarily They are not ex high, few ranges going over 3,000 feet, but there are miles of heavily hills. The air route is dotted with emergency landing fields, but to the lis W ooded lls and forests offer small opportunity for landing left and right of the course, the hi a plane safely—especially if that landing must be made in the inky blackness of the night or the impenetrable fogs that cuddle 1 close to the rround In the west, the mountains are not so

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260 POPULAR MECHANICS heavily wooded. nste: [ ‘aks, t sometimes unexpected wedge-shaped Alleghenies are a ‘rie f ridges that and sleet storms beat down from the rise one a few feet higher than the other country and strike the route. The with narrow between—not open tains are continually snowbound valleys as 1 : in the Rockies and winter. Sierras. On fair day ights, Flight over such a territory the clouds usually hang low over the moun “graveyard stretch” by day is a job tain tops and the valleys are dark with hard enough. But supplant whateve fog. And low-hanging clouds and fog ibility the day flyer may have by are the airman’s worst foes over rugged darkness, and add a blinding snow o1 country. storm to the cold, and you've got The mountains have no flat, clear table- task for the pilot. lands at their summits to afford any sort Just below thirty-two degrees F of landing place tor a disabled plane. heit, the mist in the air, or the sn Th ineir t ops and sides are either densely the sleet, begins to gather on the wooded or bare stone. As a rule, western struts, wings and tail group, and hu: pilots fly over wilder territory than do the through the air at better than a hu t tu pilots on the eastern routes, yet it o1 miles an hour packs that formation took Harry A. Smith, chief test pilot of ice on the plane. Ice is heavy. The the Bellanca company, two days to fin may seek a higher altitude in an att his way out of the Pennsylvania moun to find a colder or warmer stratum t Ss GR ALia tains after a forced la: ae aw no vent the formation. If he is barging less than two hundred wil in th “hopping the hedges,” skimming thi voods,” he said. “Some c ‘lose tops in an effort to catch the could have knocked thet rocks. marker beacons or danger *y were just curious.” higher elevations, he can't In the ‘Ing and summer, violent rai get rid of that ice. And when tl and electrical storms afflict this region. reaches a certain weight, he can't « rising sometimes without notice. In the especially if it has formed in fall and winter, fog and haze lie low over as to change the wing curve of his the mountain tops, shrouding the wooded and automatically reduce the t L. ranges from the eye of the pilot. And Given a set of circumstances like Zero Weather Doesn’t Halt the Air Mail; Scene at Chicago Airport during Extreme Cold Weather Las Winter; Planes Being Warmed Up for a Night Flight to New York

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POPULAR MECHANICS the Night Air Mail, and Interior of Cock- A. T. Plane, Showing Numerous Controls and Instruments means uncommon, and you have It’s not very often the big mo- anymore. It’s not very often the g¢, Curtiss or Douglas ships come failure of even the small- ice forms on ship mushing ng over ind the pilot can't get rid of it or he’s got to come down hat’s he rugged topography of the Hell ir the rest of the mountainous takes sides against the skill of the hearted man at the controls. The 1 lip comes down, but where and torm or fog, the pilot flies “blind,” e pays attention to nothing ex- the instruments on the board in the Perhaps the c ire,” and he in the sky bsecures even the ars from oo ilot 1 : 4 . i: ‘ he pilot loses ta 1 his other as some pil have done, to trust to his fanciful in- i int where moun

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POPULAR MECHANICS But the fire extingu had frozen. There was only thing to do—take parachute. But doing so, Nelson guided his blazing away from the field the town toward the wilderness, where n could be injured by crash of the ship. he floated safely to He got the breaks time, but the jinx oi graveyard stretc!] him in the end. A m: later, a fierce w storm proved too for him and he was f dead beside his At the End of a Flight, the Pilot Submits a Check Sheet on Which Are ar Cleveland Noted Any Details for Special Inspection or Repair neal eveland. the murky east. The half-light of day was over the flying field. Bad weather was sensed in the murky offing Over northwestern Pennsylvania, Col- lins struck it. A line squall rose out of the storm, ripped into his plane, smashed off a wing and forced him, after terrible moments of bucking and fighting, to aban- don it for a parachute. Four thousand feet up, at the mercy of the storm, Collins flipped open his safety belt, caught a strut of the remaining wing and swung out into space. He rocked perilously in the sky for a few moments and then, free from his falling craft a sec- ond, he let go. Tossed like a leaf in the swirling eddies and fierce currents of the upper air, the flyer gave himself up for lost as his silken savior swung to and fro. Then, true to the faith built into it, the great half arc opened right side up to the steadying weight of his body below, and floated safely to earth on the wooded countryside of Pennsylvania, near Mill- stone. Thomas P. Nelson, flying east with the night mail, got the breaks on November 6, last. Soon after he passed the interme- diate landing field at Ringtown, Pa., he noticed that his ship was on fire. He im- mediately turned back toward the field and began to fight the fire—shutting off his gas, turning on the fire extinguisher. The list of those have ‘died on Hell Stretch is gr more slowly these days of better ments, better ships, finer motors at than it did in the past. Many exper tests are being made in an effort the flyers nearer to the goal of po safety. More expensive equipment bought and installed. A huge cory} experts is employed continually by N. A. T. to seek safety and warn pil danger. Radio directional beams that tel flyer whether he is on his course have vided the latest and, aviators believe best weapon so far developed to safety. All planes now flying the grave route are equipped with radio rece devices. Headphones on the pilots’ tell them whether they are on the cou Weather conditions ahead are given radio. Such a system is costly. But cost matters little when money is wei against human lives, costly planes motors, and valuable cargoes. TUBE IS BENT BY SPRING COIL WITHOUT FLATTENING sending tubing to any degree wit! flattening is possible with a tool now a able. It consists of six steel-spring coils to take tubing ranging in size one-fourth to five-eighths of an inch

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POPULAR OLL TELEPHONE BOOKS TURNED INTO ROOFING PAPER telephone books serve many pur- iter their usefulness as directories lived. They are shredded and and come back as roofing paper, in linoleum and floor mats. Saw- re city directory in two, or even it up with an ax, is no mean feat, was necessary to design a special e for shredding. Shredding pawls loosely and freely around a bolt in of a rotor which throws the pawls strike the books as they are fed machine. The successive pawls triking, biting and chewing at the until these are ground to pieces. rigidly fixed for the purpose because they clog instantly. The books offer sur- resistance, even to hardened and the shredder weighs three nd has a rotor of forged nickel- impossible to use EYESHIELD FOR AUTO RACER REPLACES GOGGLES revent dust and other foreign mat- m entering the eyes of automobile a transparent shield of durable rial is adjusted to the helmet in such that it can be lowered in an instant rvice or put back out of the way. It s difficult to adjust than goggles and an unrestricted view. ld for Motorists Takes Place of Goggles, Is asily Adjusted and Gives Unrestricted View MECHANICS Life-Size Sculptures of Mother Cat and Kitten Attract Attention to Baltimore Novelty Shop CATS CLAMBERING UP BUILDING ATTRACT PASSERS-BY Persons passing a Baltimore novelty shop are startled to see what appears to kitten chasing a straight up the wall of the building. A closer inspection, however, reveals that that animals are life- be a full-grown cat size models designed to call attention to other such animals in the shop. ELECTRIC LIGHTS OVER WATER LURE FOOD FOR FISH To increase the natural food supply for trout in rearing pools, a sport men’s as- New advantage of the sociation in Hampshire has taken well-known lure of the Bright lights are placed pools and these flame for insects. just above the attract a variety of insects, many of which strike the water and are unable to rise, while the game trout often leap out of the water iat are hovering in the air near the surface. to snatch

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POPULAR MECHANICS * — p— Viselike Grip and Powerful Leverage Characterize This Tool for Removing Fittings Hidden behind Plaster NIPPLE AND COUPLING WRENCH REACHES HIDDEN FITTINGS Removing hidden fittings from behind the plaster line of walls or ceilings, such as are encountered in concealed sprinkler systems, can be done without cutting away the plaster by using a nipple and coupling wrench designed to reach these almost inaccessible parts. The pipe wrench is equipped with a T-handle which eliminates much of the possibility of accidents due to slipping, that some- times happen in probing for such fittings with the ordinary wrench. Pressure on the tool causes it to produce a viselike grip and gives a powerful leverage. DOGS FED ON CHEAPER MEATS HAVE BETTER HEALTH Choice cuts of meat are not as health- ful for dogs as parts generally thrown away, according to Dr. William Lentz, director of the small-animal hospital at the University of Pennsylvania. It would be better for the pets, he declares, to feed them on scraps and internal organs the butcher usually discards, as they would live longer and have less sickness. One reason for this, it is believed, is tha dog naturally would follow the hab its wild ancestors and prefer other of meat rather than the muscular po: usually fed to it, but man has had a dency to adapt the dog’s diet to hi and this has not been beneficial t animals in all cases. Wild beasts prey on other animals usually rip carcass open and devour the intern; gans, naturalists have observed, and dog has the same natural preference is believed that the glandular organs tain substances good for the dog, an softer diet is also more beneficial harder meats. According to Dr. He: Fox, pathologist of the Philade Zoological society, the same rule ay to lions in captivity. ELECTRIC WALLPAPER PASTER FITS ROLL FOR HANGING Pasting and trimming a roll of paper ready for hanging in a single ation, an electrically operated paper-; Machine for Pasting Wallpaper Is Electrically D and Does Away with Messy Paste Tables ing machine does away with messy | tables, pails and other equipment. roll of paper is run through the ma: passing through a paste reservoir and ing trimmed as it emerges, when ready for folding and hanging. It el nates to a great extent moving of fu ture and laying of canvas on floors @ Our Bureau of Information will an all questions regarding articles appea in this magazine.

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POPULAR MECHANICS -NCOB “STONE” \S MANY USES ubstance, as hard ny varieties of ind stronger than kinds of wood, is anufactured from bs through a me- and chemical The cobs are re- to a jellylike pulp is pressed into a id hardens into a tough material « len-tan or ysl, color. It is used nels, can be cut rears, washers and arts usually made tal, and is a substi- rh ird rubber. HEET-STEEL ROAD ENCE IS SAFER FOR AUTOISTS et-steel fencing in of wire along roads ng steep embank- gives greater to the motorists, iments have shown. heets have strong teel hinges at the ; i a ta . ‘ Setting Up a Title in the Block Letters; Taking a Photograph of It for the whic he will stand Movie. and the Letter Case bending before 7 eak. Also cars striking the sheets irp angle suffer less damage. BLOCK-LETTER MOVIE TITLES PRODUCE NOVeL EFFECTS Artistic titles for the home-1 are now easily prepared block letters that c: be with appropriate objects or to form attractive titles tha plicated with pen or penci greatest skill. There are 182 wooden letters and seventeen numerals in the set. The characters are of whitew ood and are half an inch thick and two and one-half inches high. The weights make it easy to set the pieces upright or they may be laid flat. Unusual effects can be produced by making the letters “perform tricks” with the aid of a dark string and then as- Purposely Run against Fence, to Show Strength Lite ae las he title f the Sheet Steel Used Instead of Wire sume their proper place in tie >

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Yes, it seemed as as the well-known bone He placed it in Space between the plate turned on a switch instantly the “dry” p celain began to. ste like a hot wet towel. “With the old bak By GEORGE W. GRAY PNCIENT covered their doings with such mys- alchemists and magicians tery that early science came to be known as the “black Nothing could be more typical of the change from darkness to light than the invitation lettered on the office door of Dr, Willis R. Whitney, research director for the General Electric company at Schenectady. arts.” “Come in, rain or shine,” warmly greeted the sign in bold black letters. So I walked right in. walk into wonders more fascinating than anything It was the beginning of a ever dreamed of the philosopher's stone Doctor Whitney, chemist. is the leader of a group of ex- perimenters himself a distinguished who spend their time try- ing electricity at new tasks—and the work that of the mvsterious genii is truly magical. they have succeeded in getting out ~ ~ Stepping into an adjoining laboratory, I ran into a near-wilderness of glass pip- ing, test tubes, insulated wiring, and other laboratory accessories. The magic of this room was in a curiously shaped vacuum tube. which Wires from it connected two plates stood upright and near-by table, separated by about a foot. parallel on a a distance of One of the laboratory men picked up a large porcelain insulator. “Looks dry, doesn’t it ?” 266 Largest and Smallest Coolidge X-Ray Tubes, and W. R. Whitney Listening to Electrons methods many hours were required cook the porcelain dry,” he explai casually. “Now, with this intense ra tion—with a frequency of 60,000,000 cles, five-meter wavelength—the \ job could be done in less than five 1 utes.” This simple demonstration of the ergy packed into radio waves was onl start. In another room, I powerful tube of the same type. Neat rested an enormous incandescent la! rated at 1,000 watts. necting wires or sockets, but the mom the current was turned into the radio tu saw am There were no c the lamp glowed with intense light—a k of power transmission by wireless,

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was put in a glass tube and near the mysterious bulb of en [he fly buzzed around importantly ost as soon as the radiation was on it, fell to the bottom of the tube number of flie and through an inle means *irculation of air, well below ng point, was passsed through tainer. The effect was that of a -gradually the flies dropped and ert. When it seemed that all the tinuous were frozen dead in their glass blood rose, ica, the vacuum tubé was set up reached 100 to 101 degrees. a few feet of them, and the electric \ recent devel turned into it. Presently a flv be ice is the use 1 stir, then another, and another. lever to combat certain dise a minute there was considerable suggeste Doctor Whitney

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ZO8 POPULAR new radio tube might have a use here Accordingly, he supplied the tube to the Albany medical school in New York and the Mayo clinic in Minnesota, and during the past year specialists in these institu- tions have been testing its medicinal value. Reports of their results are awaited with keen interest. Another wireless transmission of power, but in this Whitney has little con- ‘The energy ' +}y] pOsstl | le application is the yOssibility Doctor I i fidence. rapidly falls away with distance,” he explained, “and about ninety-nine per cent of the power is used in transmitting the cent, > remaining one per This is too great a cost; wires are however, a real field for the use of wireless transmission in the cheaper. There is, remote control of electrical apparatus, and here may develop an important field for the industrial application of this radia- tion.” Leagued with Doctor Whitney in this t a ROCA © many-sided exploration of electricity are Dr. W. D. Coolidge, the cist,and Dr. Irving Lang- muir, the chemist— nhvsi- though one can only wonder where the one’s physics leaves oft ind the other’s chemistry begins so intertwined now are these b isic sciences. In Doctor Coolidge’s laboratory the electronic wizards were working with a vacuum tube of a different type, an X-ray tube designed to operate at the enormous pressure of 400,000 volts. Why so powerful ? “Because we want deeper penetration,” an swered the voung scien- tist who was on the job MECHANICS here. “Our most poweriul X-ray tu use today operates at 250,000 volts a able to penetrate three and one-half in: of steel. But we make turbine cas many inches thick, and we want an X which will photograph the inner stru of the steel and show up any deep Our immediate goal is a 400 volt unit, and when that is attained hope eventually to get a controllabl ray tube at 900,000 volts.” Even now, the radiation 250,000-volt tube is so penetrating men in adjoining rooms would be i1 untarily X-rayed through the walls flaws. from tube were operated unshielded. Son them hung up a jawbone on the wal front of a holder ] containing a pl graphic glass plate. the plate, hours later, they had a ph graph of the bone, though the X-ra reaching it had traveled more than tl 1 } feet and passed through two walls. The projected 400,000-volt tube w process of exhausted of its Three pumps were working in seri being force pump in the basement, an oil pu in the room, and directly beside the Sound Track on Motion-Picture Film, and Handling Atomic-Hydrogen | at 6,400 Degrees Fahrenheit When they develo 0 eee 4 AA}. ne

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POPULAR MECHANICS y of 100-Kilowatt Radio Tubes; Six of These, in a Recent Test, Transmitted a 200-Kilow Wave Broadcast, Which Was Heard West of Hawaii cury-vapor pump of the powerful torted witha chuckle, as he put on vented by Doctor Langmuir. Be asbestos helmet and disappeares invention, hours were required to the partition. And in a moment } a tube down to the lowest vacuum = about all my eves could stand ible. And even then, the vacuum A flame leaped out in the dark rather thickly populated with air illuminated the hidden interior. |] ule Now, with the Langmuir mer from a contrivance which the pump, it 1s easy to attain within a man held in his right hand, inutes many times nearer an abso directed the flame against the :cuum than was possible at all under fire-clay crucible, the clay conditions. bubbled away like but é tor Langmuir’s inventive genius metals ran like water under the own itself in many directions, but this heat. ere more strikingly than in_ his Its temperature, 6400 degree c-hydrogen flame. heit, is the hottest that man t look through that window there,” able to produce And it is att icted the laboratory man, “and you'll by anything burning, but by all hat it can do.” atoms of hydrogen, which have | Vhich window?” I wondered, glance from their accustomed systems by the smooth wall of the adjoining tric arc to recombine into m¢ ion he had indicated, and which | atomic-hye £ iw was heavy glass, black as the duced in industry for welding | wie “Can anything be seen through such and allovs, such as chromium, Flame ness? per, aluminum and silver, as w u'll see all you want to see,” he re- ordinary iron and steel.

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270 POPULAR The anti-noise campaign now active in several cities may find an ally in a new type of gear recently developed in the Non-Resonant Gears, with Steel Ring That Slips inside Rim, to Eliminate Half of the Noise laboratories. I encountered it first in a room where two large gears hung side by side. “Give them a knock,” suggested the laboratory man, offering a hammer. I hit the wheel on the right; it rang like a church bell. Then I struck the other wheel—there was only a dull thud, and the sound faded almost as soon as it began. “Both are the same size and of the same material,” explained the expert. “The only difference is that the non-resonant wheel has a ring of steel fitted into it, just inside its rim. This absorbs and damps all resonance within the wheel—and tests show that fifty per cent of the noise of gears in trolley cars and other machines is resonance Now, if somebody will kindly eliminate the ot} noise, ier fifty per cent caused by the cogs—then we'll have really silent gears.” Quite at the other extreme is the elec- tric book, which is all sound and nothing to look at. I sat in a quiet room and a voice out of a hidden loud speaker began to read. The speaker was actuated by a film in which wavy zigzag lines of light control the sounds. The ordinary mov- ing-picture film stock is used for the record, and it has been found possible to photograph fourteen parallel sound tracks on the film—suficient to provide over MECHANICS two hours of reading with a 400-foot Radio communication, which owe much to Langmuir’s explorations wit the vacuum tube, continues to be a n line of research here. At the experim tal broadcasting station WGY, five n south of Schenectady, I saw the engin setting up the 200-kilowatt transmitt which was put to the test last March. ki membering that the most powerful broad casting station now operating comme cially uses but 50 kilowatts, you can re ize what a tremendous jump in power | been attained by the Schenectady wiza1 These five-foot super-power tub: CI when set in their water jackets, are se and one-half feet long. So rapid is heating of the plate while operating t! fifteen gallons of water per minute needed to cool each tube. Once a tu was left outside its water jacket. Wit three minutes there was a “plunk” as t! tube collapsed inward. Each of tl giant tubes costs $1,600 and has a life about 1,000 hours. Short-wave transmission also is the o! ject of almost continuous experiment at WGY. Half a dozen steel towe varying heights are spotted over the fi T acre lot, and many types of antenna are use. The beam antenna developed communicate with the Byrd expeditio the Antarctic is there. It is said that wire screen used as a reflector with antenna increased the efficiency of tra: mission to twenty times that of the wu flected wave. Another beam at W' points to Australia. Separate from this sending station the receiving laboratory which stand a high hill amid the farms north of city. Ona clear icy morning, I aros daybreak and made the eight-mile trip t | this hilltop for the precious privilege talking with Australia. Mr. A. B. Hitt : the Schenectady operator, introduced over the wireless to Mr. P. M. Fart operator in Sydney. Then, over 10,()'' ™ miles of land and ocean, we exchanged ports on the weather, discussed the that the clock was approaching midni in Sydney while the working day was }j! beginning in Schenectady—talked a nothings, of course—but it was a ting! experience nevertheless Coming out of the station into

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POPULAR MECHANICS 271 sunlight, I could barely see the peaks of the Adirondacks only a iles to the north, but I had just man’s voice halfway around the and had got his every word and clearly and instantly. Magic! Is inything in the Arabian Nights or eam of the old alchemists to equal ‘tual experience in wonder and im- bility? Such miracles the wizards laboratory are steadily and surely commonplaces of everyday life. CHERRY BLOSSOMS REQUIRESUN TO PRODUCE FRUIT matter how profuse the blossoms herry tree, the fruit will be missing dy weather prevails, or the branches close together as to shade the blos- Artificial productive during the blossoming period results shading of nation, but less than one per cent blossoms set fruit as compared re than eighteen per cent for ad- unshaded trees. TRUCK WITH FLEXIBLE FLOOR UNLOADS AUTOMATICALLY lon coal trucks are being equipped exible flooring, operated electrically principle of and unloading material is the endless conveyor. and other accomplished quickly, oring coiling. under the truck as its lls to the ground. ~ = | COd!i In loading, the on 1s reversed with Flexible Flooring on Endless Conveyor, Which Loads and Unloads Automatically Special Compartment for Warming Plates or Which Attaches to Ordinary Steam Radiator HEAT CHAMBER IN RADIATOR KEEPS DISHES WARM To warm plates or food, a steam radi- Food, ator has a special compartment with doors. The recess holds a number of arti- cles, is set at a convenient height and the arrangement does not decrease the effi- ciency of the radiator. DAM STOPS LOSS OF LAND Soil-saving dams been used suc fight the have Wisconsin to valuable farm lands through gul- and streams into neighboring states. cesstully in ero sion oO! lies Flood waters and spring rains were found to be a serious to fertile land, particularly in hilly regions, one gul menace ly h iV- ing eaten ninety acres out of the heart oi a 250)-acre farm in a few years. The gul from the pond above the dam being carried to the desired level below by lies are now dammed, the water lines of sewer tile, laid horizontally with the upward and at some distance floor of the gully, basin for the silt. ] intake curved from the to provide a Thus the gully ually is filled with earth that sett settling erad- les to the bottom of the pond area. Every gully can be forced to make its own delta and thus be kept under control. @Several successful flights with airplanes powered by outboard made recentlv. motors have been

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POPULAR MECHANICS AIRPLANE EXPANDS TO FIT LOAD Detachable sectio: increase or decrease | senger accommodat according to requ ments, are provided an airliner being structed in Holland. expanding plane is so ranged that an extra can be added or removed, depending on the num- ber of passengers to carried. The ship is | as a fast monoplane carry six people, but by adding a lower plane of equal size, the machine Cc *s a biplane Umbrella-Like Tent That Serves as Place of Concealment for Photographer becomes " pao and His Camera in Taking Pictures of Birds at a Pool room tor ten pet The change can be 1 HIDE-AND-SEEK TENT IS USED quickly and the cabin is large and TO PHOTOGRAPH BIRDS Any engine can be used, up to sixt cylinders, developing 1,000 horsepo To obtain close-up photographs of birds serememnems that drink from a garden pool, Dr. Paul FIRST-AID CAR FOR MOTORISTS sartsch, curator of the National Mu- HELPS STRANDED DRIVERS seum, uses an umbrella tent for shelter and concealment for himself and camera. First aid for stranded motorists He focuses his lenses and awaits the ar- fered by a hospital on wheels that tra rival of the birds. As many as seventeen the French highways and helps the unt varieties have been photographed in fif- tunate driver. The car is equipped teen minutes at the pool. tools to repair disabled autos and is usual in appearance, the top being d ALUMINUM-COATED WALLPAPER rated with the head and flow ing ve a nurse. The ambulance for aut Metallized wallpaper, a thin sheet oi maintained by a manufacturer to aluminum backed with paper, has come | tise his product. into use recently. It has a bright finish that does not tarnish, and when soiled may be restored by cleaning with a damp cloth, Embossed pat- terns give a variety of designs. It does not glare or reflect light, but dif- fuses the rays and is par- ticularly appropriate for sun rooms, bathrooms and hallways. Unusual effects are obtained by stippling or coloring the , metal paper after it has — ' a he been applied. nate yy ha ey eg mR yey my png Bl

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POPULAR MECHANICS 273 \OKING DOWN ON UNCLE SAWM’S LATEST BOMBER 1otograph, Taken from Another Plane, Shows One of Uncle Sam’s Largest Bombers on the Wing; Note the Pilots at the Controls and the Gunner Looking for the “‘Enemy”’ nother airplane, a photographer have the additional advantage of not st an unusual close-up picture of ring up dust clouds on dirt roads e army bomber on the wing during nis it ers launched from oe PHONE BOOK INDEX LETTERS d. The canrera was snapped as the a " as smber soared over Baltimore and SAVE TIME FOR USER «1 the pilots at the controls with the in the rear gazing about him for pothetical “enemy.” ¢ Transparent letters with gummed bacl now may be obtained for indexing the telephone dire torv to save the AIR RETARDS SPEED OF AUTOS | | artis plays a large factor in the speed of obiles, particularly at high rates of When cars travel above forty per hour, more power is required ithe, ercome air resistance than road re- ‘e. At fifty miles, +1 tions o1 | ° ; ° 2 a of the p the wind resist- ' , 4: e Siaa . last the 1e ordinary motor car is between ~~ ope nd 170 pounds, absorbing from fif to twenty-three per cent of the en power. At 100 miles an hour the @Whenever would be quadrupled. Besides in- ng speed, streamlined automobiles of the dir you find that you wish know more about any article in this maga zine, write our Bureau of Information

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POPULAR MECHANICS Humless Alternating-Current Tube That Eliminates Much of the Noise of Electric Radio HUMLESS ELECTRIC RADIO TUBE IMPROVES RECEPTION Taking the hum out of the electric radio is the purpose of an alternating-current tube recently announced. The tube was produced by the alteration of various vacuum-tube elements, and is said to re- move virtually all the audible hum that has been one of the annoying problems faced by the industry ever since the elec- tric radio was introduced HOUSES RIDDED OF WHITE ANTS BY CATCHING THEIR QUEEN White ants, or termites, which do much damage to houses in India, reducing the hardest woods to powder and destroying rugs and carpets, are attacked through their queen by the native Hindu ant catcher, or diviner. These tunneling ants work in darkness, boring under walls and ceilings and beneath and behind floors and wainscots, eating away the underside of an article that appears sound on the surface. The ant catcher taps floors, walls and ceilings until he finds a spot that sounds dull or hollow. Digging under the floors from this point he searches until he finds, about six feet below, a mud shell containing a fat white chrysalis f: which tunnels radiate in all directi The grub is the queen ant, and when removed, the workers forsake that par ular part of the underground system Sometimes a dozen or more must be moved to clear a dwelling of the pests. MOVIES MADE OF YOURSELF WHILE YOU WAIT Vest-pocket moving pictures of y self can now be made with a self-operat ing and developing camera somewhat the automatic cameras with which subject is able to take a strip of still tures of himself. The electric-powe movie camera, capable of turning out J pictures an hour, is operated by mer: pressing a button. The subject ente: a booth equipped with a telephone other pieces of “property,” which he n use in_ various poses and actions bei the cafffera. The finished product appe in a small screen frame which becom: animated through pressure of the fingé tips on the edges of the frame, four inches long and nearly two and one-half vy The entire operation, from “shooting the little booth studio to “screening the vest-pocket frame, requires only minutes. It is planned to operate self-serving movie in the same mai as automatic still-picture studios, | | a The Man in the Booth Is Making Movies of Hi with an Automatic Moving-Picture Camera ce re

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POPULAR MECHANICS . York Central Railroad Wrought-Iron Pipe Conduits for Electric Wiring under the Harlem Ship Canal; Thirty-Six Lines of Pipe Were Tied Together as Shown, Bent to Conform to the Channel Bottom and Lowered pended. The pipes were filled with oil to 1 powel LAYING WIRING UNDER CANAL TESTS ENGINEERS’ SKILL 1 } ease the operation of drawing t lines through. neers were faced with a problem re- in laying high-tension wires under SWINGING DOOR FOR ASH CAN Duvvil or the Harlem ship canal, KEEPS DUST INSIDE undred-foot stretch of water sepa- Manhattan from the mainland. : ne cables were out of the ques- they would be likely to foul the various kinds of piping had to be from e rom ( because of the danger of broken eakage, and the likelihood of rust- corroding in the salt water. The | that finally proved successful was iron piping. More than 23,000 t was assembled into lengths of voked together in thirty-six ducts ward when a engths each, and the entire as bent to conform to the bottom of shovel is pushed eam. With the aid of a diver, the against it, but returns vere lowered in less than a day, a__ sition as soon as the shovel is withdrawn, thus keeping the dust and dirt inside to the closed po when traffic on the canal was sus

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—— By JOHN V. DRAPER F EVER you have gone on a vacation tour on cushions of air, you have prob- with “auto-intoxica- hours behind the ably shaken hands long tion,” induced by o steering wheel. This condition was once known as mus- cular fatigue, but recent discoveries now identify it as nerve fatigue. It manifests itself in many different ways, such as headache, roaring in the ears, and dizziness, muscular stiffness soreness. nausea. tired eves, nervousness and sensations of falling forward. Motor-car pended shock and things that facilitate increased riding com fort. The fallen manufacturers have ex fortunes to improve springs, absorbers, cushions other majority of these accessories have short chiefly because no de available for comfort. pendable “yardstick” was measuring riding Engineers were forced to rely on human recorders the drivers and about the passengers—for actual “rideability” of different makes of cars equipped with various com- fort devices. data That is why the Society of Automotive Engineers, different dozen manufacturers, as- aided financially by a automobile Ll a/ signed to Dr. F. A. of George Washi University, the tas finding an effic method for measu comfort in autom travel. He attacked problem by origin several devices, whic! calls ‘“wabblemeters measuring the lo equilibrium, or bal which the average Car Equipped with Gauge to Show Its Riding ties, and Close View of Recording Apparatus torist suffers after an all-day excu The first apparatus featured a meta placed under the balls of the sub feet as he attempted to balance o1 If the lost his balance, the resultant movet heels for a given interval. of the bar would complete an elect circuit and would be signaled by e an electric bell or a counter. The proved design and second wabblemeter was consisted of a form balanced on a universal joint metal rods projecting from the front ners of the platform make contacts a metal bar, if the platform is move far up or down. This completes an trical circuit, and each contact is indic by a bell or counter. Another wabblemeter is similar t one just described except that it is equipped with special pumps whicl erate like pistons and move a certain whenever the platform is forced out

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ce. The fluid is collected in a grad- tube where it is measured. e successful operation of this device Moss to which Doctor invent yet another emeter ol produces a graphic bodily automobile a plattiorm mounted and-socket joint and loss of balance or hat results of the after long It consists ef os , is equipped register the re ecording pens that of the t est on a revolving drum. mechanical penmen draw a straight hen the motorist under test lications whatever of loss of equilib- Wal recorded as up iriations from this straight shows bles are and line. results of the experiments indi- that riding fatigue does not repre- very marked muscular fatigue, but closely approximates what Doctor terms nerve fatigue. erly have claimed that any Scientists such con as nerve fatigue did not exist. Re research, however, has brought to umps Subject Riding a Stationary Bi- cycle Fitted with Instruments That Measure the Muscular Fa- tigue Experienced in the Proc- ess; Scientists Are Determining How Tired a Person Becomes in Driving, and Why light the interesting reduced measurably in in conducting impulses and that, under conditions of exercise, they display chem ical and energy changes very similar to those shown in a fatigued musc e Students who volunteered for the tests were first of all subjected t mental tiplication for five-hour periods to t mul deter mine the normal nerve f: induced by such effort Thereafte were tested in number checkin: peed of re action in tapping hand steadiness an as; metabolist indi vidual These were taken automobile ides ‘anging fr 150 to 300 miles. on long om over a variety of roads At the end of each trip, the “tourists” again examined as above. An eight road as much as 16.9 per cent in number were hour ride over a very rough showed a decrease of efficiency in checking as com pared with an average decrease of 2.6 per a-°

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POPULAR MECHANICS being made more comfortable by the of specially designed cushions, Protessor Fox, aided by several lea automobile manufacturers who condu supplementary tests at their pri grounds, developed a standard bump by means of which the riding qualit any model or make of motor car ma readily determined. The standard | is an obstacle, five and five-eighths in wide and two and five-eighths inches | fastened to the experimental high The test car is driven over it at diffe: speeds, while the gyro-accelerator, that ee ball a ee Rta Les, cent as a result of fatigue produced by mental work in the laboratory. The gvro-accelerator, originated by Prof. M | Fox. of the University of Iowa The “Wabblemeter.” Which Measures Loss of Bal , i 4 and a Gyro-Accelerator Installed in a Car is the most efficient instrument yet devised for studving the actual automobile mo mounted in the tonneau, records tions which cause fatigue. It gives an ac- happens. When the car hits this s curate measure of those forces which dis- lated bump, a portion of the thru turb the occupants of the automobile dur- absorbed by the tires. Then a moti ing a long drive. developed by the bump that causes Riding discomforts which induce mus- body to nose down before it reacts t cular and nervous fatigue among motor- effect of the upward thrust caused b ists and passengers are due to vibrations front wheels passing over the obstruct at certain speeds, the sidesway of the mo-- This upward thrust forward produ tor cars, the force with which the riders movement of the car body in cou are thrown when the cars pass over bumps clockwise direction as viewed from or chuck holes, the fit of the seat cushions right side. The front of the car and the noises of both automobile bodies gradually to a peak position and and engines. The causes of noise and starts downward again. When the vibration are being ferreted out and rem- wheels pass over the bump, a rapid cha edied by motor-car manufacturers as rap- takes place. idly as may be, and many automobiles are The time at which this reaction |

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POPULAR MECHANICS ir combines with the motion of the pends on the speed of the machine its wheelbase. Ii it combines ore the front end attains the peak mn of its upward movement, the resembles a strong “kick,” and is bjectionable to the occupants. At peeds, this rear-end motion com- th the front-end movement in vay as to be more or less neutral- the body motion. lowa State College, riding-quality ive been made by U. L. Gunder M. Mason, engineers in the de- nt of mdustrial arts, who have a of suggestions for the man who king of making his automobile last vear or so. A little attention to portant to keep them inflated to the degree recommended by the manufacturers. In a closed cat unpleasant noises and vibrations arise when the rubber bumper against which the doors close be come worn or loose. Install new bumpers or use paper wads, o1 g Lack of Equilibrium after Long Ride, and a Breath Test other material, for a temporary on Motor-Car Passenger after a Long Journey solution of the trouble Some imple t3 by Nnoint 1] san j -operlvy adiusted do mple details, they point out, will times an improperly adjusted doot e some of the more bothersome put 1 nd jars. can be it n order by giving the lower hinge a twist with a wrench. This throws the a human being, an old car needs bottom of the door over and up, causing ittention than a new one. For in- it to close more tightly. it should be greased more fre- Many drivers pay too little attention to v. Grease the springs to keep out the cushions. Few seat cushions but don’t use lubricating oil on them, out entirely, but most of them v if the car is not equipped with mnewal or repair after long for the oil will make them too of the chief reasons being that the spring le and the car will suffer needless push up against the padding and thereb: Snubbers are recommended for develop uncomfortable hummocks. This difficulty is easily remedied by replacing ‘ommon source of discomfort may _ the old pad. Another important point he wheels. Balloon or semi-balloon the shape of the cushion and the ive proved to be more comfortable of the bottom pad the high-pressure type, but it is im- of much of the strain, to help support hi i To relieve the drive:

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POPULAR MECHANICS

Test Car Equipped with Gyro-Accelerator to Measure Riding Qualities, and a Bicycle-Wheel Velocity Recorder Attached to Running Board legs and give greater ease in driving, a seat pad that inclines toward the rear, tending to hold the occupant of the seat against the back, has been found better than a level pad. A block of wood slipped under the front edge of the seat cushion often removes a common source of dis- comfort. Many persons enjoy a pad that has much resilience, but on rides especially, a comparatively solid one will long usually produce less fatigue. The reason is that, if the cushion is too soft or springy, the body will keep bouncing up and down with tiring results. 7 comfort chiefly on the mat- ter of springs, the The problem of car rests r design of the auto- and other that the owner usually can- not alter without great expense. The shock absorber was developed to an- swer the need for greater comfort, mobile, lactors

owner purchases installs a set, he sho make sure that the ticular type he choos is suited to his car. RADIO MOVIES ON STEEL TAPE Recording radi movies on a thin ste band instead of a | recently dem< strated successfully Berlin by a Hungat inventor. The object be reproduced scanned by a ray light as in ordinary ture transmission, instead of being phot was graphed, is recorded a moving steel band the form of magneti areas of varying ck sity. This is acco: plished by convertil the light into energy by means of the photoelectric c and passing this energy into two elect: magnets between which the steel t from one roll to another. 1 the strength of the electromagnets with the intensity of the reflected s« ning ray. At the receiving station procedure is reversed. elect passes AUTOMATIC POULTRY FEEDER OPERATED BY CLOCK To enable feed going neat poultrymen to flocks regularly without “7 chickens, an feedet been made toru! electricity. A ti! clock allows the oper to set the feed h matic attachm«: pers for any desi hour. Grain, w! released, is s¢ tered by a spread For night feed:

a lighting atta but before the car Automatic Poultry Feeder Operated by Time Clock, Which Feeds Chickens at Any Hour Desired ment is provided

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POPULAR MECHANICS 281 PAINT ICE BLACK Music Scale for Children Con- sisting of Drawings of Animals, ro OPEN LAKE ii") : First Letters of Which Repre- sent Musical Notes iuse black absorbs in’s rays and holds an ice-bound ner in Lake La near the head- s of the Yukon was liberated from inter ice one month er than usual. With ms and buckets, a of lamp-black and ned refuse oil, twen- e miles long and feet wide, was ‘bed across the ice e lake to the river. month the strip cut a channel a foot ANIMALS DEPICT MUSIC NOTES is evenly as though sawed, and it TO TEACH CHILDREN nued to grow until the Yukon lib- the lake water with the spring Instead of ordinary enabling the boat to get under wav. senting the scale, a o~ - uses drawings of animals + BIG MACHINE GUN MOST DEADLY porve of ee ee | WEAPON EVER MADE principles of m f} escribed as the most deadly weapon ing is the same as that of tl made, a machine gun capable of fir- in the scale, “D,” for insta animal OT object represented hity-caliber bullets at the rate of 800 picted by a donkey, and “E” nute for a distance of nine miles, re- The method has been found vy was demonstrated before a group the first steps in music for the overnment officials at Washington. _ by attracting and holding their uper-gun, much larger than the ordi- kind, will be used by the navy which contracted for manufacture of the pons in this country. HUGE OFFICE STRUCTURES RUN LIKE A SMALL CITY Managing a big office building scraper is almost the equi ning asmall modern city. One storv building in New responds to a city police department, health depart cleaning force, departmen and electricity and one for In the building itself are a hospital, library, recreation paper, brokerage office. e' rants, and shops catering to need. The elevators carry m cers than the street cars of mai cities, transporting 50,000 pe A private telephone exchange and a m and letter division aid in intercommuni- ine Gun That Shoots Fifty-Caliber Bullets at the ; oe , Rate of 800 a Minute for Nine Miles cation between tenants of the building

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POPULAR NAVY BATTLE IN SHOW WINDOW IS RUN BY CLOCK TI iree miniature war vessels go through all the maneuvers of a hot naval engage- MECHANICS trolled by an arm going around onac mutator. The entire action is regula by a time-clock arrangement, but ii clock is cut off while the boats are in tion, they will complete the battle return to stopping. port bet Every part display, includ guns, is built to a 41 tile of one five-hundredt! an inch. QUEER TRACTOR DOES WORK OF | SiX HORSES Miniature Naval Base in Which Tiny Vessels of War, Governed by a Time- Many Intricate Maneuvers Clock Arrangement, Go through ment in a tin av as window display tion because ot t the precise movement of the boats in the The bay is fitted like a first-class part ot a has attracted much 1 he mystery surrounding atten water. naval base with wireless towers that work, a fort, guns, a lighthouse and a warship, 1 5 | over and a submarine, each boat 1 i a dest1 carrying a wireless tower. They are not attached to wires or strings, each independe 1 moving nt} he “+ nad recr itlyv and they cross and recross each other’s path. A moving story is told in the n tering t upon fire, the flash of the guns and the splash of shot laneuvers, an enemy submarine en- h e bay past the lighthouse, where- coast-defense guns open the seen. sub- the out and travels under water until it is able to fire submarine Starts being The merges a cruiser a torpedo at the cruiser, which is hit. The undersea crait comes to the sur face and leaves the harbor with the destroyer in pursuit. The latter craft then tows the cruise: back to port, the boats all tal ing their original positions, when the action tire maneuver one-half minutes. is controlled electrically. The en three and The display Dry cell batteries are used for opera- tion and radio tubes enter into the construction, there being 3,000 feet of wire and 300 con- nections. Nine volts is repeated. takes are devel- oped and the movements of the boats and the firing are con- Mesigned especiall row-crop farming four-wheel-drive tra has proved itself capable of perform any that a four o1 It has three-p traction, e bling it to pull its load in loose o1 task on a farm team suspension with horse can do. balanced soil such as encountered in the corn belts. eliminated in making turns up or hill in dirt, and for cultivatii rows and can be atta cotton Skidding front wheel loose straddles two cultivator or other It has a thirty-inch clea to any two-row implement. between axles and ground, and the ride the cultivator and have complete control of the tractor. erator can haying, it straddles the windrow, and also lister or horse di handle a double-row bottom-plow, as binders. well as Steering is done with the con tional gear connected to the front wh« Showing Flexibility of a Four-Wheel-Drive Tractor Which D the Work of Six Horses on the Farm

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POPULAR MECHANICS 283 CAPTIVE PLANE GIVES ALL THE THRILLS OF FLYING ze- Captive Airplane Held nd Tunnel Where Novice Work Controls and Expe- nce Thrills of Flying ng some of the tions of flying with- ittendant risk, an device full-rigged ement con- of a eairplaneinawind = thrill seekers. The tunnel is thirty feet long and inside hip, seventeen feet long, with short A sixty-horsepower motor swings ght-foot propeller to maintain a 100- an hour wind, causing the plane to about six feet off the ground. In this tion all the movements of a real ship ght may be simulated by operating controls. In addition to its value as musement, the apparatus is expected e of use in instructing student fivers. IS attracting HALT CARELESS AUTO DRIVERS WITH LINES OF LIGHTS utomobile drivers who frequently ig- the ordinary stop lights at street in- ections, can be made to heed the sig- by a different arrangement of the England have disclosed. tead of having the signals suspended | poles, a line of red lamps is imbedded e pavement entirely across the street. n traffic is to be stopped, the lights switched ps, tests in on. Being set so as to be v visible to the driver, they give a warning and are much more rigidly erved than the usual lamps, according The lights are flush with the with to reports. pavement passing vehicles. so they do not interfere TWO-WHEELED MOTOR PULLS SLED THROUGH SNOW Using the engine of an old automobile for power, a Vermont man who does much winter traveling over snow-covered roads, has tractor to draw his sled. constructed a_ two-wheeled The engine was mounted on a pair of large, wide wheels, the take-off chains to the wheels Che sled 1 Loar power being connected by large enough to haul a bulky Two-Wheeled Homemade Tractor Used to Pull a Heavily Laden Sled over Snow-Covered Roads

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284 POPULAR MECHANICS GLIDER WITH SAILS DEPENDS ON WIND FOR POWER | nome | Aiter a year’s experiment, a flight recently made in a glider equipped a sail to provide motive power. The is hoisted after the glider has been to by an automobile until it rises. As a sult of the successful tests with one the inventor said that, with a mainsail a jib, it will be possible to glide throu the air, using the canvas for motive poy Ce aa Glider Provided with a Sail to Furnish the Motive Power; When Once Launched, the’Craft Uses the Canva for Power and Guiding Much Like a Sail Boat in Water DIVERS AFTER PEARLS TRAINED FROM EARLY CHILDHOOD Pearl diving, searching for oysters on the ocean bed in 150 feet of water, requires training from childhood, and even then, the mortality rate is high. It has been estimated that there are 100,000 men who live by this hazardous means, virtually all being South Sea natives. The “skin divers” work naked, without armor, crews of them traveling together to the pearl banks. The diver’s only equipment is a rope about his waist and an instrument, like a clothespin, to hold his nostrils He stands on a large stone, fastened another rope, and with the aid of weight reaches bottom when helpers up the stone for the next descent. diver walks about picking up peari oyst which he places in a small basket. He ! about two minutes in which to fill it three minutes is the maximum time can hold his breath, even after years practice. Besides the risk of staving do too long, the diver also is facing the d ger of attacks by large fish and is c stantly subjected to the terrific pressu

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he water which es seventy pounds e square inch at 120 A too sudden as- may bring on the ls,” an affliction well n among of civilization. a hard life with ts dependent ce, and a short time a diver who brought the surface a perfect pearl weighing fifty ns and valued at 000 went insane n he found how much share of the profits ld be. caisson ers on KIDDIE CAR FOR USE IN WATER »aid children in over- ing fear of the water, quatic kiddie car pro- much sport and at same time trains the ingsters to like the ter. It has a canoe- ped wooden frame floats on a rubber be resembling an auto- obile tire. The child is ited that there is enty of room for free vement of the legs in 50 ; not capsize. irrying to the beach. Aquatic Kiddie Car Consisting of a Wooden Frame Attached to an Inflated Rubber Tube POPULAR iter or floating and kicking the legs. e tube is wide enough so that the craft It is collapsible for ease MECHANICS —_— Rotary Snowplow Which Is Attached to Front of Four-Wheel-Drive Truck; It Makes Better Speed Than Tractor-Driven Plows ROTARY SNOWPLOW ATTACHED TO FRONT OF TRUCK walking in the Rotary that attach to the front of four-wheel-drive trucks instead snow plow Ss of to tractors have been employed suc | cessfully by the California highway com- mission in clearing passes in the Sierra Nevada mountains. The truck-operated | plow makes better speed and travels from bank bank in better time than the usual tractor-driven plow, and the wheels of the truck do not break the The | plow is operated from the cab of the truck, | swinging on a boom from side to side, the rotary wheel the and i | throwing it deflecting plate which tosses it to the side of the highway, out of the way. snow to snow roadbed as a tractor sometimes does. digging up snow against a

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This Safety C Opener Fits Table or W } with Brack« } and Operates | Turning Cran} Knock-Down Furni- ture _ Is Not New, but This Is a Novel Application of the Idea to Upholstered Pieces; the Method os Saves Shipping a Charges and Re- duces the Cost of - Packing | . , — . ’ , ot -* - Tomato Slicer Takes All Sizes and Cuts the Same ‘ Thickness » Ks it The Interlocking Fastener Strip at : Left Is for Sewing onto Dresses to he Eliminate Hooks and Buttons; at 4 Right, a Dustpan That Has a Comb for Cleaning the Broom 286

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oe . ——* - Combination Electric Dish Washer and Drier; It Supplies a Torrent of Suds for Washing: Breeze from an Electric Fan Does the Drying >. geigeeiie: Covers for Shoes, bers and Slippers event Soiling Cloth- g When the Foot- wr Is Packed in nks or Bags; They Keep the Leather from Being Scratched, and Fit Tightly Note Arrow Point- ing to Slot in Edge of This Electric Iron; the Slot Per- mits Ironing under Buttons without Breaking Them » if . ‘ . 9 i Holder for Nursing Bottle Is line — oe & Easily Attached to Crib and Is Th =o ~ Be > 7 . | oh Said to Insure a Steady Flow of a " an : e led W Milk, Preventing Infant from way or iipped Sucking Air; It Also Keeps the Bottle from Breaking Saeco ; -

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POPULAR Close View of Combination Telescope and Stop Watch, and How Moving Cars Appear to Observer TELESCOPE WITH STOP WATCH HELPS CATCH SPEEDERS a Dutch combina- To detect automobile speeders, levi police inspector has devised a tion telescope and stop-watch arrange- ment which can be operated night or day by one man, and is accurate to a degree not possible to the unaided eve. If a car is approaching at a speed that seems to be excessive, the levels the in strument and peers through the eyepiece of the blunt observe! telescope. By means of prisms in the glass, two images of the car appear, one the true and the other a dis placed image. The two images coincide after the car has run a certain distance The stop watch is then started, the prisms MECHANICS are adjusted to produce two images more and when they coincide again, policeman stops the watch, notes the t recorded and, after measuring the dist between the middle of the tires of the which has halted, is able to mine, with the aid of a set of table been exact time consumed by the car ing over the distance involved the first two and second coincidence of images. This quickly enables to tell whether or not the car was exc: At night images are ing the legal speed limits. measurements and based the lights of racy and simplicity of the method, it the added advantage of permitting observer to remain in a concealed posit the car. Besides the FLY WITHOUT LEAVING GROUND IN COMPRESSED-AIR PLANE All the sensations of flying are po without leaving the ground with an tion trainer, consisting of a small fied airplane mounted on a base cont ing pneumatic control apparatus. means of compressed air, standard the plane about as air currents affect ships in flight. rudder bar and stick control other | matic pistons, which tend to count: cockpit, is moved those moving the trainer, when prop manipulated. Thus the occupant, by ing the controls, tries to keep the p on an even keel, his success being cated by an efficiency dial. The cont are standard, and the sensation is sin to that experienced when a full-size p is flying. While intended primarily a aid in training student flyers, it is suitable as an amusement device, a operated attachment starting the that compresses the air. Plane Mounted on Base Containing Pneumat Controls to Simulate a Ship in Flight

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POPULAR MECHANICS ALLOY AS LIGHT AS ALUMINUM AND AS HARD AS STEEL nts have been granted a Swedish on an alloy that is as light as ium and hard as steel. It can be turned and drawn and is much er than aluminum. It resists alka- es, and may find use in airplane, lane and shipbuilding industries for ind propellers minum The alloy consists and chromium which are in a high-frequency electric fur- here mixture of the two metals is | by electrodynamic means. DIPPING-NEEDLE COMPASS FINDS IRON-ORE DEPOSITS 1e hands of the prospector, a miner’s ; or dipping needle proves a serv- guide to the location of magnetic re deposits. The magnetic needle anced on a horizontal axis within a graduated from zero to ninety de- in quadrants. In reading the dip, »bserver holds the ring in his hands, ng the needle north and south, and west himself. The inclination of weedle as read on the scale shows the Dependent on the geological forma- tion and the experi- ence of the ob- server, the needle aids in approximat- ing the probable mass and depth of the ore from the surface. Held hori- zontal, it serves as a regular compass. RUSSIAN PATENT OFFICE TO AID FOREIGN INVENTORS the handling of patent applications satents in Russia and foreign coun- a patent concern, known as Pritz, has been organized in Russia under rnment control. The patent office ts to aid foreign inventors who wish ploit their products in Russia, to in- ‘e Soviet inventions into state in- ies, and to acquire patent rights for oviet, and foreign patents in Russia broad. Electric Washing Machine and Pump for the Cleaning of Large Windows and Skylights ELECTRICAL WINDOW WASHER CLEANS AND DRIES For the mechanical cleaning of windows and skylights, an electrical washer now ts available. A water hose is connected to the machine, water being drawn from a tank by a pump that feeds it into the hose nozzle. Clear water is available for rins ing and a squeegee is attached for drying KNOTLESS TOWROPE FOR CAR IS EASILY ATTACHED Appealing par- ticularly to wo men drivers, an automobile tow- rope that is in- stantly fastened without knotting now is available. The ends of the rope terminate in ball-like knots and these are slipped through openings in the line near each end formed by weaving separate sections into the rope. The greater the pull ex- erted, the tighter the fastening becomes.

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POPULAR Garage Attendant Wearing Roller Skates to Help Him Speed Up Service to His Customers ROLLER SKATES SPEED WORK AT GAS STATION Employes of a Chicago gasoline-filling station have equipped themselves with roller skates to speed up’ the service to customers. Station attendants found that they made better time skating over the concrete driveway from car to car than walking. ELECTRIC EYE GOES TO WORK IN OFFICE AND FACTORY Photo-electric cells, the so-called elec- tric eye used as the toy and tool of science, have been put to work in office and fac- MECHANICS ing metal that the human eye cannot dis. cern. It also automatically operates th, lighting systems in offices and factories turning on artificial illumination as re quired when the intensity of natural light diminishes, and can be made to contr street lights in similar fashion, turning o; lights as required without waste. A beam of light thrown across a doorway will count persons entering a room, and the cell can be made to sort packages by de tecting differences in appearance, and to operate a fire smoke appears. extinguisher as soor CLOCK WOUND BUT ONCE A YEAR KEEPS PERFECT TIME Requiring only one winding a year small clock that keeps perfect time for that period owes its unusual feature t an invention enabling a small timepiec to run by a comparatively large forc Heretofore eight days has been about t! maximum that.a small clock could kee; accurate time without rewinding, becaus when larger mainsprings were used for longer periods, the tension of the spring decreased as it ran down to such an ey tent that variation in the time resulted The year clock, which can be mack small as two and one-half inches square consists of an ordinary watch without the mainspring. The independent spring self-takes up most of the room because must keep the clock operating for a yea Jetween the spring and mechanism ar two miniature coil springs, similar to those used on. scree tory, performing many involved tasks with automatic and unerring accuracy through the me- dium of interrup- tions of a ray of light shining on the cells. In the steel industry, the cell is used to determine temperatures of steel in the blast furnace, the tube mill, or rolling mill, the eye detecting doors, and a whee which stretche them out when turns. The larg spring turns the wheel that stretch the small co springs which cor stitute what corr sponds to the matn- spring of the ord nary timepiece. 5; increasing the siz of the spring, the length of time be changes in bril- liancy of the glow- Small Clock with a Large Independent Spring Which Requires Winding But Once a Year tween windings can be increased.

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Telephone Laboratories Flying Laboratory of the Bell Telephone Company Winging Its Way over Long Island; Note the Mast- Type Antenna behind the Wing of the Fuselage EN you turn the dial to your favo- not as perfect as they might be, the real ite broadcasting station, and the trouble is mostly at the sending end, in im comes through all mixed up with the opinion of Arthur O. Austin, of tles or fades just when it is becoming berton, Ohio, an authority nteresting, who or what is to blame? quency electrical currents. re than likely, you criticize your set, While your favorite broadcasting haps you complain about some in-_ tion is an excellent example of the rence in the neighborhood. While it ress made in radio science, he admitted that some receivers are there is much room for Bar- on high-fre- Sta- prog- nevertheless improvement. itry Surrounding KNX’s Transmitter as It Appears from the Air; Field Before New Insulators Were Installed; the Outer Line Shows Effect of the Change the Clover-Leaf Pattern Indicates 291

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POPULAR MECHANICS listener's set is abou same as that required by a fly in climbing an inc or so up a window pane After years of traili radio troubles in broad casting stations, e1 neers have brought light an important It is, simply, that larg. masses of metal, like the towers that hold up an tenna wires, or the stee framework of the build ing on which the statior is situated, are set into electrical vibration, or os cillation, whenever the The sending wave of many stations car- ries with it a lot of straggler waves which spread out and rub elbows with other programs in near-by channels. This lack of sharpness in the main is the cause of imperfections not only in its own program but also in those of other stations. Over- lapping of the straggler waves causes whistles and other noises. The presence of whistles in a program does not mean, necessarily, that other stations are wandering off their assigned paths, Mr. Austin points out, but it is an indication that they are sending out more than one wavelength, the fundamental one and a lot of extra ones that do nothing but make trouble. You can get a clear picture of this by tossing a large stone into a pond of water, and then throwing several small pebbles after it. The large Tubes in the New Transmitter, and One-Ton r stone will set up a train of waves, but the weight That Holds Down Antenna En: ’ s*¢@ i * ; * ; . ) . Wi perfect form of these waves is destroyed station operates. They absorb part o1 by the smaller waves created by the peb- station’s energy and send out wave bles. their own. The largest broadcasting stations in this Sut perhaps by listening to Mr. Au country use 50,000 watts for regular work. youcan get a better idea of this condit Fifty kilowatts of electricity is equivalent “Any radio tower,” he says, “has a to sixty-seven horsepower—more than the ural period of electrical vibration. ! majority of automobile engines develop— oscillates slower or taster than the s¢ yet the amount of power received at the ing-wave frequency, it will cause int

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POPULAR MECHANICS ators for the Towers to Improve Operation and View of Tower Showing It Insulated in Sections ‘nee, and may be said to ‘cast a shadow.’ ou could fly above the towers and see electrical shadow, you would notice it takes a shape somewhat like a rure ‘8’ in many cases. The shape would licate how the energy was being distrib- | about the station.” Years ago, during the World War, Mr. \ustin started to solve the radio-tower blem. In helping the navy, he worked it the principle of the sectionalized tower. consists, essentially, of a steel tower t is cut up into sections, each of which parated from the other by a set of por- n insulators. Thus, instead of there ¢ one single tower, there is really a of small towers, one above the other. war ended before the navy stations ‘ built, and Mr. Austin’s sectionalized ers were forgotten, temporarily. hen station WHK, Cleveland's pio- ‘ broadcaster, decided to build a new onalized transmitter. Although ham- ed by a power restriction to 1,000 watts and a low wavelength, the station is now being heard in Honolulu, New Zealand and all over the United States, achieving results that in some instances are com- parable to those of its super-power broth ers and it is hoped that it will be able, some day soon, to try out its new equip ment with much higher power. Plans are under way for other transmitters of this type, probably modified to consist of a single tower, itself acting as antenna.

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294 POPULAR MECHANICS YOU NEED’NT FEAR POISON IVY—IT’S EASY TO CURE Poison ivy and its SS ; night, when ba: . . s near relatives need ee Ge! lf ages cannot be no longer be feared we. ‘ changed or moi by the camper, Z ie ; tened, clean th hiker or picnicker. o> ee oa skin surface care Simple chemicals, ym 4 Fuck ) ae fully and leave it obtainable at any att, on: Sg exposed to the air drug store, are ef- ad Itching can be les fective both in pre- . sened by imme: venting and curing ing the poisoned plant poisoning. parts for severa One of the most Upper Left, Fruit, Leaves and Aerial Rootlets of minutes in water a successful remedies Powgp-Ivy Branch: Gute, Gableat Poison Ivy; Bish, hot as can be borne for oak, ivy and su- or by applying hot mac poisoning is a five-per-cent solution towels. The itching increases during the of potassium permanganate in water, ac- treatment, but is followed by great relie! cording to Dr. James F. Couch, poison- In early poison stages, do not apply o1! plant expert of the department of agricul- or greasy preparations, as these tend ture. The solution is applied to affected spread the poison. Later, when the poi: portions of the skin with a bit of absorb- material has been exhausted, zinc-oxide ent cotton. The potassium salt destroys ointment or a similar astringent or ant! the poison, and its only effect on the skin septic of mild nature.can be used. Thesé is to leave a brown stain that can be re- remedies are for cases of actual poisoning moved easily with a one-per-cent solution after inflammation has appeared. Muc! of oxalic acid or sodium bisulphite. If trouble can be avoided, however, by « the skin is too tender for treatment with ploying simple preventive methods. Aite: these chemicals, several washings with returning from a hike, wash the expo soap and water will remove the stain. Ox- _ portions of the body several times in alic acid is a poison, and should be kept and water, and rinse thoroughly. away from the mouth. Inflammation caused Dr. James B. McNair, of the Field Mu by ivy poisoning can be helped by such seum, Chicago, has found that a solut simple remedies as local applications of consisting of five parts of ferric chlorid Epsom salt or baking soda (sodium bi- in ninety-five parts of a half-and-half m carbonate). Use one or two heaping tea- ture of water and glycerine will prevé spoonfuls to a cup of water. The solu- poisoning if applied to the skin befor tions are best applied with light bandages embarking on a trip in ivy-infested of clean cloth, kept moist and changed’ gions. Or one part of ferrous sulph frequently to avoid infection. During the _ in five parts of water can be used. The

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POPULAR MECHANICS tions are applied to the skin and al- d to dry. jison-ivy plants are most easily rec- ized by their leaves, which always are led into three leaflets. The fruit is a tish, waxlike berry that stays on far the winter, after the leaves have dis- eared. Young leaves are a glistening becoming green as they grow older. persons not well acquainted with on ivy, a safe rule is contained in the ng, “Leaflets three, let it be.” CONCEALED RADIO FOR AUTO IS EASILY INSTALLED nstallation of a recently produced ra- set for the automobile is a compara- ly simple matter, only a little more ed than placing a similar set in the +, and, when the job is completed, all are concealed except the control on the instrument board. The an- nna is installed in the roof of the car, ordinarily consisting of a copper screen, ough sometimes a special installation necessary for the open car. The re- ver is located on the engine bulkhead, ow the cowl, and the speaker is carried the receiver case, beneath the cowl, hough it may be placed in other posi- ins. The car’s storage battery is used the A-supply, and a battery box be- eath the floor carries the dry batteries r B and C-supply. Eliminator units are talled, if necessary, to stop interference ym the various electric devices on the CAR STORAGE RC ond DO (A B\TIERY BATTERIES | © |{@8) wing Method of Installing Concealed Radio Set in Auto; Only Control Panel Is Visible The control panel is equipped with tomatic volume control, and with a itch operated with a key. Rubber Waders, Worn as Trousers, for the Angler Who Likes to Venture into Deep Water RUBBER WADERS FOR ANGLERS WORN LIKE TROUSERS For anglers who desire to venture into deep water, rubber waders are supplied that are worn like wading waist-deep. and allow They can be worn over or inside shoes and are equipped with a waterproof pocket in front. The material is as light and pliable as the cloth of an ordinary garment. trousers HYDRAULIC DRIVES FOR TOOLS German tool builders are experimenting with hydraulic drives for certain parts of machine tools, and have found them much more simple for the tables of planers and the heads of slotters and shapers than the trains of gears and other mechanical mo- tions usual for such machines. Hydraulic drives for these parts make possible uni- form and controllable speeds without vi- bration, greater output and automatic safeguard against breakage because of the impossibility of exceeding the designed pressure on the tool. Reversal, as in the case of planer tables, is effected silently and definitely, with no screeching of belts or rumbling of gears. During the war, an English tool builder operated the car- riages and tool slides of heavy lathes by simple hydraulic cylinders, and the prin- ciple is coming into favor again.

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POPULAR MECHANICS INSULATED WIRE ~ Curing Dynamic Speaker of Rattle A little kink which |} been found very useful in working with dynamic speakers has to do with loose turns in the voicy coil. This condition n cause a great deal trouble, as it makes speaker rattle. The r edy is very simple. Fi remove the cone fri the speaker unit, wl may be done by tak out the bolts that h the cone assembly to the field; then unsolder the leads to the voice c from the transformer in the frame. This will ex pose the coil so that the loose turns of a wire car be located. Get a tube of good household ¢ ment and apply it freely to the coil. Use the fin gers in doing this and be Bringing In the Antenna Lead Every experienced DX-listener knows that a carefully installed antenna is quite necessary in order to log distant stations. One point in the usual antenna installa- tion that is frequently the cause of poor DX-reception is the careless manner in which the lead-in is brought down to the set. The lower sketch shows a simple stand-off bracket that anyone can make and a method of installing it which may be applied to any type of roof. A good soldered joint at the point where the lead-in wire is connected to the horizontal portion of the antenna is essential. If pos- sible, make the lead-in and the antenna proper all from the same wire, extending it clear down to the antenna binding post on the set. If this is not practical with the materials on hand, make the connec- tion as shown in the upper sketch, plac- ing the strain of the horizontal portion entirely on the insulator. The twisted leads should be scraped and filed bright before the solder is applied to the joint. careful not to leave any high spots to hit the collar of the field magnet.—James E, Whitney, Wenatchee Washington. Power Tubes Operate in Series from Five-Volt Tap The writer recently desired greater out put from an a.c. push-pull amplifier a: decided to substitute 245 tubes for 171-A type then in use. Not having extra 2.5-volt winding on the transform: I decided to connect the filaments of the 245 tubes in series and work them off the 5-volt winding pro- vided for the 171-A tubes. This was done in the manner shown and worked out nicely.—Ross Plaisted, Cleveland, Ohio. UX-245 5-VOLT SECONDARY ~~~ CENTER TAP FOR BIAS “——« Q000000 nnn VV UX- 245

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WH ever thought of talking back to the loud peaker is made to talk and not sten, and yet it is possible to speaker ? hack—and here’s how: \nv loud speaker can be em- ed as a microphone. While ; relatively insensitive, as com- red with the carbon or condenser mi- hones now employed for broadcast- the speaker will handle the close-up ce quite nicely. For this purpose, an litional speaker should be employed | attached to the radio set or amplifier, erve as the pick-up in place of the ial radio-receiving circuit and detector. here are different methods of cutting the loud-speaker microphone, depend- on various factors. In the case of a lio set provided with a phonograph jack pin jacks, the loud speaker is simply nnected in place of the phonograph k-up. In the case of an ordinary radio the loud speaker be connected tween the grid and the filament or cath- the set not to nflict with the loud-speaker pick-up. In e case of a power amplifier, the speaker ivy be connected to the input of the first tage. A little experimenting will soon licate the best place to cut it in, follow- the foregoing general suggestions. may with detuned so as he most sensitive type of loud speaker use as a microphone is the concealed or concave diaphragm in a baffle- te and box. If a person. talks directly the diaphragm, quite close up, the itivity is remarkable, although the e reproduced in the loud speaker of the 10 set will be rather tubby and even muffled. For better tone quality, with some loss of sensitivity, the speaker should talk at the diaphragm from the side, so as to eliminate the hollow effect. The double-diaphragm type of loud speaker is remarkably sensitive if talked to from the rear, through the usual open- ing covered with a screen, as shown in the upper photo. The talking is repro- duced in a tubby fashion, but rich and deep. If a higher-pitched voice is desir able, the loud speaker should be talked at from the front, preferably close to the center drive pin, which is the most sensi tive area. It will be during ments that the loud speaker occasionally groans and howls, sometimes to the point noted such experi where the loud speaker employed for the microphone cannot be used in the same This is due to the electrical coupling existing between both If the microphone loud [ corner of the room. acoustic and loud speakers. speaker is taken to a far room, or if it is moved in different direc tions or sometimes tilted tally, the howling may cease. horizon This very handicap may even be put to use for an even amusing experiment. If the second o1 microphone cone is brought close to the receiver loud: speaker, there will be the most awful shrieks imaginable, emanat @7

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298 POPULAR MECHANICS ing from the usual respectable speaker. By dexterous handling, the operator can almost play a tune by this means, some- what copying the radio music instrument played by waving the hands. Shrieks, groans, dog barks and other effects can — rt Left, Phonograph Pick-Up Employed as Microphone; Above, Sound Effects duced by Holding Loud-Speaker Micro; Up to Set Speaker one to the grid of the tube the other to the negative po the C-battery. An A-battery heat the filament and a rheo to control the filament volt be obtained. By rocking the microphone speaker in one’s arms, a most unusual lullaby can be produced, to the edification of all present. The electromagnetic pick-up may also be employed as a microphone. All that is necessary is to fasten a piece of stiff paper, folded in half to form a V-shaped trough, on the usual needle. By talking into the ‘paper “V,” when the pick-up is connected with an amplifier or receiving set, the op- erator may become his own announcer. A paper cup also serves as a microphone when fastened to the needle of the phono- graph pick-up. Laboratory Voltmeter Employs Tube most delicate of the usual types of voltmeters and milliammeters re- quire some energy to actuate their mech- anisms and are unsuitable for measuring the very minute signal voltages and cur- rents in the grid and plate circuits of a radio receiver. tube Even the For such use, the vacuum- voltmeter is very efficient and has the added advantage of being very simple and inexpensive. It consists of a CX 301-A tube with an accurate low-scale miliammeter, a B-battery in the plate cir- cuit and a C-battery in the grid circuit. Two terminals are provided in the latter, complete the circuit. In pract the input grid-circuit terminals are « nected in the circuit whose voltage be measured, and the current in the circuit is read on the milliammeter. voltage in the grid circuit can then be termined by consulting the calibrat chart of the tube voltmeter. Shielding of Neon-Tube Leads Improves Television Pick-Up The detector and amplifier circuits o! radio receiver used in television work in a measure, affected by the action of t! neon tube used in the scanning sect Sometimes this seriously affects the cla: and definition of the image frequenci impressed on the pick-up circuits. It been found that, by shielding all the le running directly to the neon tube grounding such shielding, the pick AMPUFIER TUBE \ SHIELDE NEON TUBE— , LEAD STEEL ARMOURED CABLE Above, Diagram Shows Position of Wire Shields io Circuit; Below, Methods of Shielding Leads

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POPULAR M nsiderably improved. The m indicates just where these are and how they are | S@MMIER led. If the user can obtain IN DASH lead tubing and introduce eon leads through it, an al- perfect shielding can be ob- Instead of this, a small hielded cable be used almost as good results, al- vh lead is to be preferred. nd each and every bit ding as shown. CAR FRAME can of ‘ken Sockets in Power Packs | Bn i ld UV-type vacuum-tube kets are useful for replacing ken sockets in power packs, where tifier tubes of the 280 or 281-type are A socket for this use need not be the cushioned variety and one of the type sockets serves the purpose nicely. kets having metal tops are preferable the molded types, owing to the heat rated by the rectifier tubes.—R. J. ted, Cleveland, Ohio. High Line Voltages Reduced for Standard A.C. Sets \ step-down 50 to 60-cycle trans- former is designed particularly for standard receivers to be exported to foreign countries 110-volt current is not This transformer aid to have a loss of but 6 watts with a tempera- e rise of less than 20° C where common. is The capacity 150 watts and the step-down range is 220 240 to 110 and 120 The above specifications make the ‘former ideal for use in warmer cli- tes. It comes complete with plug, cord bakelite receptacle. all inting in the cabinet. and volts ready for or further information on anv radio truction article write to the radio de- tment; this service is free. [ GROUND TO » ECHANICS 299 PLACE FUSES HERE WHEN SCREEN INT pop car) | A+ BAT $ GROUNDED POST PLACE FUSES HERE WHEN A~- BAT. IS GROUNDED PLUG CONNECTOR TUNING DIAL. OPENINGS FOR TRIMMIN® TUNING CONDENSERS | VOLUME CONTROL Fi SWITCH B ANDC BATTERIES oe SS | Installation Diagram, Showing the Various Units and Cabled Connections of the New Receiver for Autos Kit Makes Auto Receiver A series of newly designed parts for the construction of an automobile radio receiver has recently been announced by an eastern manufacturer the frame and hard- ware, control panel, terminal block, bat- tery box and special speaker to mounted behind dash. Five tubes are used, three 224 heater-type screen-grids, and two 112-A. The tubes are arranged with filaments and heaters in series-par- allel the storage two These include chassis suspension be so minimize the drain « The stages of screen-grid r.f screen-grid 112-A power-output stage as to n battery. circuit has power detector resistance-coupled a.f.. and Photoelectric Cell of Rugged Construction A . tolvtic,” ‘wet” iotoelectric, or rather “pho- p! cell is now available which com- bines the sensi- of or gi the of It very 1 tiveness the vacuum cell and gedness liquid cell. said to be stable and efficient over the light-in tensitv ranges em- ployed in sound- reproduction Its low impedance lends itself to SVS- tems the design of a practically distortionless reproduction circuit.

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i» FIBER DISKS 2 0R “6 THICK 4” DIAMETER BOLT -—” ad ” PIECE OF ),” DIA. DOWEL WIND ON THE WIRE USING #36 DSC. ABOUT 1,000 TURNS FASTEN ENDS OF COIL TO WOOD SCRWS - . nile, , Small Choke Coils Suitable for Modern Cir r fee cuits May Be Conveniently Mounted on Short Metal Brackets; Below, Screen-Door Spring Used to Take Up Antenna Strain; the Wire Noisy Microphonic Tubes Are Easily Loop Prevents the Antenna from Falling if the Located by Lightly Tapping Each : Spring Breaks Tube While the Receiver Operates —~étife- ~ TO TUBE AMMETER nsucator SPRING ¢ FILAMENT POSITION. FOR AMP. READING 2 RAPID SHIFT OF VOLTMETER| ~ /—g-—-—T SWITCH NECESSARY TO PREVENT COOLING OF THE FILAMENTS HIGH AMPERAGE SUPPLY Left, Many Experimenters Have Ruined Their Am- meters Trying to Connect Them in the Filament Cir- cuit of A.C. Sets; to Do This Safely, the Switch Shown Is Used, the Tubes Being First Allowed to Heat to f 110-V Pryd) Operating Point with the Switch Lever in Position “A’’; Then Occasional Readings May Be Taken Right, Voltage-Divider Prin- ciple Applied to Battery-Op- erated Sets Equalizes Drain; RI and R2 Are Graphite-Path Variable Resistors, Either 250,000 or 500,000 Ohms Left, a Pendant Switch and a Length of Lampcord Ex tending from the Radio Receiver to the Telephone F a Time and Patience-Saving Device, As It Is Usually Necessary to Turn Off the Set When the Phone Is Use; the Switch Is Merely in Series with One Lead of the A-Battery or in One Side of the A.C. Supply Line to the Set; Below, Taking A.C. Line-Voltage Reading wit Meter Equipped with Test Prods; Partly Withdraw At tachment Plug from Wall Socket as Shown

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NECTIONS - a el a, [——-—* de-Practice Device, Utilizing Line Hum stead of Buzzer; Right, Heating A.C. Tube Filaments a Full Minute before Testing BINDING POSTS DRILL HOLES “ea SMALLER THAN TUBE PRONGS “SCREW HOLES — ; FOR MOUNTING 7 A Handy Layout for Charging b Radio Batteries from a 110-Volt 72 ; D.C. Line; the Lamps Are in Parallel and Connected in Series with One Side of the Supply Line and the Battery, as Will Be WRAP SMALL WIRE Noted by Tracing One of the ee ee 2 , 4 110-Volt Leads with the Large ~ ' Switch Up; the Ammeter Is an ord SOLDER Auto-Dash Type; Test and Mark Leads to Battery for Polarity before Connecting; if Ammeter Shows Discharge, Reverse Am- meter Leads; the Small Switch Is Always Opened for Safety When Charging, and Snap Switch Turned Off When Battery Cur- rent Is Going to Receiver Above, Mounting Tubes with- eae 10 X12) PANEL it Using Spring-Clip Sockets; ee ; Ce ese | the Leads Are Soldered Di- : switcn rectly to the Ends of the ( { Prongs; Below, Testing Type- , 9 Tubes for Plate Current vith an Ordinary Tube Tester: | Tube-Base Plug and Extra Socket Are Required; Be Sure Filament Voltage Is 3.3 Volts snap { +t \ ATTACH CLIP TO +45 VOLTS Switch} 4-PRONG Ux SOCKET CaTTACH CLIP 7 TOP OF 222 ———_—__I 10-V._ LINE } TERMINAL STRIP

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POPULAR FLAGHING LIGHTS ~ COMMUTATOR OF FLASHER: ~~ Method of Suppressing Interference Caused by Flashing Signs The method illustrated in the diagram will be found effective in reducing the dis- turbing interference from flashing signs, and may be installed by the owner of the sign at small cost. The filter-type con- densers used must be rated for a working voltage in excess of 300 volts. The two condensers are connected in series across the line, as near the interfering device as possible, the middle connection between the condensers being taken to ground as shown. A power-line filter between the a.c. receiver and the wall plug will still fur- ther reduce inter- — ference of this type, which is often picked up by the power lines and fed to the set, the power line acting as qn antenna. A line filter that will suit thig purpose was described in detail in the May issue MECHANIC BAKELITE ROD i DRILLED AND TAPPED | S of this magazine.—] SS J. Plaisted, Cleveland, Ohio. Extending the Life of B-Batteries Modern not B-batterie seem to cause nm when nearly exhausted as did earlier types any rate this is the they are qui run down by a large set In this condition have a high resista and cut down the age, but if of them are conn in parallel for each 45-volt unit, they be used as long as the voltage is If condition when two enough to operate the receiver. eral batteries in the same available they may be connected in allel series to obtain the high voltage Tinfoil Fuse Protects Meter Meters used by radio experimenter rather expensive and should be protected with a suitable fuse in case a short oc in the radio circuit. A mounting fo purpose may be made by drilling and | ping a short piece of bakelite rod from « to end and screwing it on one of the me: binding posts as shown. A threaded b: rod, with suitable nuts and washers, vides the insulated circuit terminal at opposite end of the bakelite rod. A row strip of tinfoil, cut as shown in 2, is then placed on the outside of the sulated section and held in position screwing the nuts tight against it at b ends, to provide a good electrical connec tion. The foil fuse should be cut as 1 possi blow ——_—_—_--—— TINFOIL FUSE TOW as without out on a not load. If bake rod not able, a ‘dowel may be u: provided it is ! boiled in paraffin remove all trace moisture.—R Williams, Chica ‘ is a\ wood

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W would you like to increase the lume of your present magnetic er? Many radio fans who cannot a dynamic speaker will appreciate ults obtained from their old speaker he addition of two field coils. genetic speakers of the popular types a large permanent magnet to fur- the flux. As the clearance between agnet and the speaker coil is at least n., there will be plenty of room to nt the field coils, which are wound on Removing Magnet from Cone-Speaker Assembly agnet legs. e coils, wound with No. 20 gauge lows: Make a cardboard form, as shown enameled wire, require 350 turns on in the sketch, holding the core form and magnet leg to permit operation on the ends together with gummed paper. ee dry cells. After the form is completed, slip it over e best way to build the coils is as fol- a small block of wood, that fits snugly in the core opening, and into the end of the block pound a nail which is clamped in the jaws of a hand drill, to permit fast winding of the coil. After the coils are made, they should be painted with black as phaltum paint and al lowed to dry overnight then placed on the mag net legs. Then you are ready to connect them Get a small compass and hold it near one ot GUMMED PAPER HOLES FOR the magnet poles. If thi : wiRE ~ “arr . = is the N -pole of the OPENING TO SLIP COIL SQUARE PAPER act > ¢ — \ h . or | Pra magnet, natural] the | | | | wae ove ee eae , “S"-pole of the compass qunaaen MAGNET-POLE _- ; ; nthe at PAPER FLAPS ~ * |7 OPENING a J needle W il] be attrac ted a ° 4 CARDBOARD ~~ tND VIEW to it . he needle 1] CROSS-SECTIONAL chesteus and the needle wi - SIDE VIEW —_ . } . : . VIEW COIL ENDS (oe rest in this position Now — - connect this single coll COM CONNECTIONS — to the. battery Checking Field-Coil Polarity in Respect to Magnet Pole; Below, Coil- : . 1eedle retainge ste Construction Details needle retain it

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304 tion, then the current flow through the coil is correct. If, however, the needle is kicked away when the current is applied, this means that the flux of the coil is op- posing that of the magnet pole, and the battery connections should be reversed. Mark the coil leads positive and negative. Now move the compass to the other pole of the magnet, repeat the polarity test and mark the leads from this coil. The Checking Service Voltmeters High-resistance voltmeters employing multipliers are now common and, when NEW CARBON RESISTOR FILED AWAY _—-» TO OBTAIN PROPER READING ON METER ( y y ol- pove.e \ ohn, WIRE AND ¥ is 0 }Low + wae © o| HIGH + Fic. 2 POPULAR MECHANICS This, how- new, are usually accurate. ever, is not always a permanent condition and the meters therefore should be checked at intervals with a standard in- strument. The writer has had some ex- perience with a number of good meters that were equipped with multipliers made of coated glass, contact being made to the resistant material through metal bands. After a time in service or lying on the NI two coils are then connected in series, positive to negative, so that the current flow through them will be in the same di rection as when they were tested, and the coil field will assist the magnet field. Many speaker units that have been dis- carded, due to poor magnets, can be re stored to normal operation by using the foregoing method, and your present = speaker can be increased in volume. shelf, the meters were found to be fro: 20 to 100 volts out of line on a 500-vo! scale. The instrument was labeled ohms per volt, the resistance of the in strument with the multiplier being 1,00) \| times 500 volts, a total of 500,000 ohm ° Removing the old resistor, which tagged 490,000 ohms, a 500,000-ohm 1-watt carbon resistor was substituted for it. In this case, the resistor selected gave a read ing slightly higher than standard. 1 meter was connected to the output of 3-eliminator in parallel with one of know: accuracy, and the carbon was then fil as shown in Fig. 1, until both meters read alike. This is an easy way to make a re sistance fit a particular case. A double scale meter of good make was purchased from a salvage house; this meter was companied by an external resistor for t! high-range scale of 250 volts, but nor for the low-range scale. With this ma terial to start with, a very handy instru ment was assembled as shown in Fig. 2 Enough wire was unwound from a b bin-type resistor, salvaged from an electrolytic B-eliminator, to give a re ing of 4% volts on the second scale whe: connected in series with the meter and 4\%4-volt C-battery. This length of w was doubled to make a_ noninduct winding when wound on a small woode! spool, as shown in the sketch. The met was mounted on a rubber panel and stalled in an old leather-covered came: box. Four binding posts were provided and, with a C-battery in the case, cont nuity tests as well as high and low read ings could be made merely by switching the test leads —Edwin J. Bachman, Fu lerton, Pa. 1 Oxy @ Defective rectifying tubes cause dist tion and weak signals.

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‘r, is that anvone pen the doors, and, this is all right in lrawing, therefore. Garage Doors Opened from Car By GEO. M. HURD OST of us object to getting out of our erated mechanism, in which the doors in order to open the doors of are opened by turning a key switch on ize, especially in bad weather, and the post. The use of a key switch makes rawings show how this can be the garage just as secure, when closed, as lhe mechanism is simple, and _ it is with a lock on the door. made and attached to the doors As shown in the detail drawing, the left- ne handy with tools. Two forms hand door is fitted at the top with a well device are shown, the opening braced bracket of l-in. angle iron, 3 ft. m in both being the The second one shown is pler of the two, since all necessary to operate the a pull on a rope attached t placed at a convenient beside the driveway. The intage of this, ONDUIT nterr rv, it is not ad- in the citv. The Getting Out of the Car in Bad Weather to Open the Garage Doors Is Avoided by Means of the Simple Automatic Door Opener Described in This Article electrically op

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306 POPULAR MECHANICS long. To the outer end of this is pivoted another angle, running over to a flat-iron link on the right-hand door. This angle is 5 ft. 3 in. between holes for an 8-ft. opening. For larger openings, add 1 ft. to La ®: STAKE WITH LE ~ 4; BOLT FOR y " “| CATCH i ‘ fis i" \FLAT-1RON LINK oe ‘ WEIGHT ‘\ PULLEY 1 ANGLE IRON —- Cl \ / t the length between holes for each foot ad- door is released and swung in. This « ditional opening. The link is made of two both doors, the left-hand one shut! pieces of 4% by 1-in. flat iron, 3 in. between first. holes, pivoted at the door end to an angle For the electrical mechanism, a wo le iron on the door. From the L-end of the _ bar, 1 by 1% in. by 4 ft. 9 in. long, is p : 3-ft. bracket, 10-ft. of 4%4-in. rope is run to a pulley on the right-hand door jamb, and fitted with a counterweight sufficient to open the doors when released. The doors are held closed by means of an ordinary spring garage-door bolt, fastened to the top member of the frame and socketed on the right-hand door. When this catch is released, both doors swing out. A stake is driven in the ground at the open position of the right-hand door, and a spring catch is fitted to the bottom of this door, latching on the post. This door ar- rives at the open position first and the catch holds it, while the other door com- pletes its travel. To close, the right-hand oted to the top of the frame as sh the pivot being 12 in. to the left o/ bolt. the bar by a piece of cable. An old ! starting motor is mounted above the ) on the wall, about 9 in. from the « end of the bar, and a piece of cable i from the bar, wrapped around the e: the motor shaft, and fastened, so when the motor runs, the cable w: around the shaft, lifting the bar and it the bolt. A spring returns the bar, with it the starter armature, to posi! The battery can be mounted in any venient position, and the motor ma wired either through the door bolt, ' The end of the bolt is connected t hy Cc

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POPULAR cally breaking the circuit as soon It is withdrawn, or else wired di- the switch; battery, motor and the latter turned off but it is the poor being in series. In key switch must be the door opens, le system, since a contact e made at times through the door \ city- motor might be used, provided g load would not be sufficient the fuses, and this might be offset the motor. ng arcking and burning. 1g The switch on the suld be of a standard type for out- ise, and should be housed in a rprooft box. ere there is no necessity for locking rating mechanism, it consists sim- i rope run from the end of the bolt, a hole in the garage and out to here it is run over a pulley and »}a convenient height for the driver an ir to reach. 1 Clothesline Holders for the Basement hed to the joists of the basement hey can be swung out of the way needed, the clothesline hangers ited have been found highly con- They consist merely of 1-in. i tf suitable length fastened to the th one nail. A notch is sawed > lower end of each holder to take Knots tied in the rope near the lders keep the line taut.—William Philadelphia, Pa. ne Holders in the Basement Can Be Swung Out of the Way When Not in Use MECHANICS 307 FLAT Ss TOC A 60°OR 90° CONES Toy Consisting of Two Cones Appar- ently Defies Gravity by Rolling Uphill Toy Man Rolls Uphill Apparently defying the laws of gravity, this amusing toy man seems to roll uphill. The toy consists of two cones, made of metal or wood and mounted on a suitable pin with their bases toward each other, but separated by a gap. \ piece of flat stock is drilled and placed between the a free-run- he flat stock out of thin cones on the pin, this bein; ning fit. The upper end of carries a figure of a man, cut metal, wood or cardboard, | end is weighted down to hold the figure upright. Two straight sticks are placed on a table with the ends diverging, the spread ends being set on a block as in As the double cone is the lower end of the dicated. track, it will immedi ately roll to the higher end. The of travel is voverned by the angle of the cones, a 90° cone moving faster than one of 60 A 90° cone, 3 in. in diameter, will climb a track elevated about 34 in. on a 15-in. track. Although the cones seem to travel uphill, close observation show that they are really rolling downl Salt Shaker for the Camper The usual salt and pepper shakers can not be carried conveniently in a camping outfit. It is, therefore, much better to use the small containers in which pep] and other spices are sold as in closed tightly—Harold E, Benson, Den- ver, ( ‘olo.

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the car has no differential, one whe: § the other must skid on rounding corn TRHE MAN or boy who attempts to use even with an exceptionally narrow tr an old motorcycle engine in building All of these difficulties are eliminat a cycle car is always confronted with the by building a single-wheel side drive, problem of final drive. Placing the en- illustrated herein. Its principal object gine under the hood to imitate the big #8 that it doesn’t look like the stand automobiles involves complications and @utomobiles, but that, experience expense, and results are not always satis- | Proved, is a minor point, and it does a factory. In the first place, there must be With nearly all the machine work a very long chain, or series of chains, run- | ™anded by other types. ning from engine to back axle, and, sec- Another thing; having the motor at ondly, a solid axle, with a sprocket be- Side makes it accessible to the driver « tween the wheels and split bearings, must While under way and keeps it much c be used. This last has many disadvan- than under a hood, even with : tages. For one thing, the body must be Panels. As most of the motors us: high to clear the drive chain, and, since this purpose have seen a lot of set they demand a good deal of adju and accessibility at all times is an portant feature. (een All the “machine” work PASSENGER . . ° . quired for the little car s here was done with a hac! and drill, with the exceptio: welding and bolting a heavy TRANSMISSION . bicycle sprocket to one — 60” WHEELBASE —————__- wheel. Incidentally, these v Fic.! GALV- SHEET HOOD > me - BRAKE PEDAL ——— B - STEERING CORD (t / CLUTCH PEDAL ui T ‘ STEERING POST SET IN 2°x3°"~~ CORD PASSED : a a THROUGH HOLE IN — ACCELERATOR PEDAL AXLE AND WRAPPED — . AROUND; END SECURED : DRIVE CHAIN ~ —- WITH STAPLE BRAKE BEAM Fig.2 PLAN 308

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hat Cycle ¢ b > hea Handy 2s id been lll use ravear onacycle 1 by a motor that the motor insmission are sup | on two paralle of VR in. iron his particular mo very early model ), and as several nd vere produced, ybable others can be obtained for or surfaced, Oregon pine, are reasonable figure. The original, in. The main frame is 14 in. wide ¢ with transmission, chain, etc., long. The 5-ft. wheelbase perm turning urchased by the writer for $5. It on a short radius, provide he tread is excellent running order. Other at least 26 in. Bolt the frame members | motors require different mount- and motor supports together with 16 course, but a similar mounting carriage bolts, the nuts being on the ly be adapted to them. A sugges- tom, except on the front riven in the final drawings. where they should be on top i your motor—and in this con- front axle can turn. ‘ : t one ot tne li elec ehter tvpes, for Steel axles are plet ty of power in a small one— wood axles, and 1 vith t le main trame or chassis, tie plates screwed down over them, illowance for the style of motor shown in Figs. 4 and 5. g required. General outlines of is offset, to allow room 1 Ss arrangement are given in Figs. BRAKE BEAM 3X 25% 28 TENS framing shou be used, re alata : —— PASSENGER + ginal having been built of 2 by 3. ™""" gga : } rg A ; ee ff throughout. Net , ‘ these in finished, Note tl FRAME MEMBERS betwee C SON if ‘ “4 1.: . ———— axle on the leit side. lis 1s iderable load here he axle to ft

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310 POPULAR MECHANICS

In the matter of wheels and axles, if Build up the dashboard and dumn you have any choice, select the largest diator (Fig. 6) from 34-in. material and strongest coaster wheels : available, disk-type > oy < bly is bolted t preferred. In our —S: car frame as s! car, we used 11-in. in the drawing wheels with a 4%-in. front end of t! steel axle and roller steering post i bearings. This has in a hole bor: proved strong the forward enough under load, member of the! but larger axles assembly. A c would be better. A emres The PLATES” pin throug! 14-in. wheel with a \ brace then shown. The asse1

e shaft, and a wa an . §KING BOLT WITH —— ; %-in. axle would \ a prevent it from be ideal for this fF AL. : ing out the das} purpose. In locating The steering gear, Ke eae) pulleys to cari Fig. 3, is of the Se steering cord, | simplest type. A one ahead of secondhand wheel and shaft can be other so that the cord will not clim purchased from an auto-wrecking yard the drum. There should be at least fora small sum. Cut the shaft to about turns of the cord on the drum, se 36 in. in length and make a wooden drum __ by a staple on the middle turn. Note 1 for the steering cord. Ii no lathe is avail- the cords are crossed below the dru: able, carve the drum from a block.of white cause the car to turn in the right pine. It should be 3 in. in diameter, 6 in. tion. A good grade of sash cord sl! long, and as true as possible with the be used, as ordinary rope stretche shaft. Secure it with a long pin in a hole much under load. See that the cord drilled through the shaft. not rub on sharp corne! Left, Details of Brake Bea and Shift Lever; Right, Vi« of Dash; Below, the T: Box and the Drivewheel

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GALYV. METHOD OF POPULAR SHEET IRON \ \ “I -—“\{ ALUMINUM Cid PAINT ,-S.LorT f - --> FASTENING HOOD t \ ood pa ssed fastened te ur Cc pat o shave away teer FRAME — STF WIRE be neces- some of to prevent this ing ends of the cord through holes axle, wound three with staples. ime. It may ‘ wooo In the d two or times installed axles and and fo. chain ine lik locate the motor, \ SCREWED TO provision FRAME some the this is done sim ning drive ar, B"HEAVY DUTY moving the transmis WELDED TO HUB ind forward on but ot a differ be necessary motor | bars, require rrangement. It may ay places in the wood allow for . ete., but do not cut out enough ma to weaken the frame. It bette ise the motor or set it out farther. xt build the brake Fig. 4 simple but efficient type riter on a It ne pe r- alle het Fic.7 may to rame mem- protruding nuts, carbu- is assembly, Is a very by the w been used series of small cars and coasters. ke beam « 1as of a single bra ons —— BICYCLE SPROCKET ——*") MECHANICS SMALL FUEL TANK UNDER HOOD 3x 6 PINE ORUM Fic.6 oI _ ROLLER BEARING A radiator Slots that a wire h up al hood hold the rols model Cont ticular case, with Ror in used, erator 1 nown as 5S ate d cap is bolted to the should be cut 1 OK d give must the original the the latter 311 BOTTOM CUT FROM COPPER Ol. CAN FOR CRANKCASE LUBRICATION oot lever A the the use, by c f a W ire cable. holds from through tension beam spring away not in heels when hose and pieces of rubber nailed to the ends are for brake shoes Make of W ood of iron the hood galvanized tre sheet with along the edge metal hood in the wood strips so frame can be turn to in the side n a quarter lace adapted to the par In our and pedals were be f engine used. levers the accel exception of pedal was made the a . > . ig. #7, to connect with

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312 POPULAR MECHANICS carburetor through a wire cable, the ten- sion spring on the carburetor keeping the BAR OR PIPE -~ ply is that it reduces the fire hazar, which, however, is very slight, since the SUGGESTION FOR MOUNTING OTHER TYPES OF ENGINES REQUIRING TRANSVERSE SUPPORT throttle closed until the pedal is pressed down. The original gear-shift lever was cut down to about 8 in. long, and adapted to the car through the original tie-rod, which was sawed off to suite The double- acting clutch pedal was also installed, al- most without any alteration. These con- trols are placed conveniently so that the pilot has at least one hand free at all times for steering. The kick starter is left on the transmission intact. Thus the mechanism is complete, with gas accelerator, gear-shift lever, clutch and brake as on a big car. Footboards are built around these controls, considerable fitting but neat job. requiring making a very Screws are used so that the en- tire floor can be removed quickly for in- spection of any chassis parts. The driver sits on a cushion laid directly on the floor; the passenger has a raised seat, about 4 in. higher, behind the driver. One of the passenger’s feet rests on a sort of shelf or guard built over the chain, the other on an extension of a motor-support frame member Tools are carried in a box un- der the passenger’s seat. A salad-oil can, with screw cap, is used on our cycle car for gasoline fuel. It holds only about \% pt., but this is enough for four or five miles at a filling and that is as far as parents care to have their young pilot travel at a time. Another advantage of the small fuel sup- tank is isolated under the hood, and shut-off valve instantly accessible out lifting the hood. For the cranl oiler, a bright new copper oilcan the ten-cent store is used. The bott is cut out with a can opener, and it is 1 suspended on the dash with the soldered into a small copper feed pi A shut-off valve regulates the oil sup in proportion to the speed of the engi: This design of cycle car has proved markably compact, solid and free fron bration. With its low gear-ratio it pu up surprising grades without speed; in fact, it has frequently to two coaster wagons, each with two sengers, besides driver and ger on the car. The total expense, excepting labor including motor, transmission and al tings was approximately $15. Thi cludes secondhand wheels valued at each. Paint is also included in this ure. A striking job was made wit! Indian-yellow light-green with aluminum-paint trimmings, and nut stain on the floorboards. The wh: were left in their original orange. With any smal! air-cooled motor tween 1 and 4 hp., this little car can ea be duplicated. You may be will not run into any great expense, will you encounter any serious const! tional problems. Speed depends lars slacl one pa chassis, assure:

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le r for POPULAR MECHANICS the size of the drivewheel, but as geared, fifteen miles an provides plenty of thrills and at the time is a safe rate on outlying riginal is Keeping Dirty Rain Water Out of the Cistern order to keep the first wash of rain which is usually quite dirty, owing iccumulation of dust in the gutters, the cistern, the arrangement illus- has been found highly satisfactory. sists merely of an inverted Y-fitting ped with a valve to divert the water er direction. A length of heavy tied to the handle of the valve, run through a pulley and over to a driven into the ground so that a lipped over the cord, can be hung under the open end of the fitting licated, the other end being con- to the pipe which runs to the cis- tern. The valve is pulled over so that the first wash will be di- verted into the pail, which, when filled, pulls the valve over in the other direction automatically, and the clean water is run to the cistern.—R. L. Starzl, Le- Mars, Iowa. Oars for Ship Models making of wooden oars for ship lels being a slow and tedious task, I ded to try bamboo and found that the could be made in one-fourth of the previously required. In addition to make, bamboo oars are tronger than those made of wood.— Michnik, Chicago, III. easier to large safety pin makes a convenient metal tokens; a en of them will go on the pin and they easily be removed as needed. street-car PA AAT i i WW Paper Bag Tied over Mouth of Food Grinder Catches the Crumbs Bag on Food Grinder Catches Crumbs When grinding bread, crackers and sim- ilar kinds of food, which make crumbs, it is a good idea to tie an ordinary paper bag over the mouth of the food grinder as shown. The crumbs will be caught in the bag, which prevents getting the table messy. I always use this method and find it a great convenience.—Mlrs. J. C hard, Manhattan Beach, Calif. Rein- Cushion for Driver Insures Comfort When two persons drive the same car, one may desire to use a cushion but the other not, which is sometimes rather in- convenient for the former finds the cush- oo as he usually i — sf ion somewhere rN UT | on the back seat. A rood method of keeping ~ Na the hs cushion at hand is shown in the drawing. It is fastened to a short cloth one end of which is tacked to the seat. not wanted, it is the seat. strap, When the cushion is merely thrown behind

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Ew outdoor sports can equal archery for pure fun and skill. The twang of the string and “plank” of the ar- row reaching its mark, whether that mark be a target or light game, have a brand of music all their own. But take your bow and arrows into the work shop, add a gunstock, aittomatic trigger and arrow guide, and you have a weapon that will open the eyes of other sportsmen. It can be held in any posi- tion while shooting, speeds the arrow on \< way at the touch of the trigger with a little practice, can be mad hit the bull’s-eye every time. The bow itself is made of o orange. Secure a piece, cut dow: 54 in. long, and then shave it unt is 2 in. wide, 3 in. tl at the center and thick. Then place it vise and trim down c fully as in the draw and Fig. 1. Build a wood-stear box, Fig. 2, long enou to take the straight b with a l-in. hole in end to let in steam f: kettle. After stean for several hours, bow is limp and may allowed to dry ona bo

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eth Murr ‘ RA‘ € d with forming pegs, Fig. 4, made of of broom handle. This will make ke on the reflex shape according to urve shown in the drawing. e stock, of any good hardwood, is cut out on a bandsaw. Black walnut used for the stock illustrated, but maple or oak are lly satisfactory. The k is 41 in. long; 25 from the end drill a e as in Fig. 3, which hen squared out for trigger mechanism. irrow guide, trough- ped, is cut out from hole to the end of e stock by means of a ige, as indicated at the Fig. 4. ie trigger mechanism ists of three parts, trigger, spring and ng catch, and may be from. brass to the ipe shown in Fig. 5, } vood patterns may be with a knife from wood and taken to a ss foundry. The parts are pivoted in place in the hole in the stock with steel crosspins driven through the wood. In the underside of the stock, 1 in. from the “muzzle” end, drill a - in. hole, three-quarters of the way through, and into this drill a bolt hole from the muzzle end of the stock. The bow can then be fastened to the stock with a 4 by 214- 4 - in. stovebolt and washer. the nut being introduced as in Fig. 6. The “nocks,” Fig. 7, which are slots in the bow ends to engage the string, may be carved di rectly in the wood, if de sired. A more finished appearance is given by attaching bone nocks. These are filed 315

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316 POPULAR MECHANICS

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POPULAR MECHANICS rom pieces of cow- to the shape shown ll. They may be ed with pumice and ightly to the bow friction. Waxed inen cord is used e string, braided hree strands, as in arrows are 28 in. nd made of birch ng. The points are ed down to take an cartridge shell, 14. which is dented side with a punch ke it hold securely. feathers are split razor blade and ed for feathering, may be done with a clamp like the _ striking the target, appear simultaneous. ustrated in Fig. 12, or with a home- Never pull the trigger without an arrow ood vise. Use a good waterproof in the gun, as the string will snap in two. ind the feathers will hold securely. The bow gun may now be finished by may be dyed any color desired be- staining the stock and varnishing both attaching. stock and bow. A suitable target is made convenient quiver or carrying case . from hay or straw board with cords and 8) can be made from a piece of cow- covered with white oilcloth on which the 22 in. long by 9 in. wide, joined with _ bull’s-eye 4s painted. of the same material on the side In shooting the bow gun, it is not diffi- aving as a bottom a round wood _ cult to secure perfect aim every time, and tacked in place. with considerable practice one learns to gure 10 shows the arrow in position allow for “windage,” that is, the strength e bow ready fora pull of the trigger. of the wind throwing the arrow off its old the arrows securely on the stock course. This is much less than with the shooting, flatten the ends of two ordinary bow and arrow, however, as the pieces of brass rod, bend them over bow gun is tremendously powerful, and, nsert in the end of the stock, as due to its speed, the arrow is less affected in Fig. 13. They should barely by wind and gravity than otherwise. the arrow and are positioned so as The usual precautions should be ob yw the feathers to pass freely. served while on “shoots.” The gun is per- ter stringing up the bow, Fig. 16, you _ fectly harmless without an arrow in it, so ready to try it for strength. With the arrow should never be inserted until ite caution gradually bring the string each shot. Practically any kind of small to the trigger catch, as in Fig. 15. On or large game may be hunted and, because necessary depends the strength of | of the accuracy with which the gun sends and the bending of the bow must _ the arrow on its way, misses will be found > gradually in order to “break it in” few and far between. splintering. If found too stiff, it . ild be shaved down gradually, trying @A short chalk line, held taut with both ch time. When at last the bow is of hands over a glass or metal surface in right strength (and it should give stiff which it is impossible to drive a nail o1 tance), an arrow may be inserted for tack, can be snapped easily by the teeth, il. Such is the speed of the bow gun if a short length of string is attached to the pulling of the trigger and arrow _ the center of the line.

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~ /SK-TARCET RACK By HI SIBLEY T HAS been a time since we anything in our ne borhood that cr so much excite: as this mechanical shooting gallery. B with air rifles came by the dozen, and livery service was temporarily suspen as milkmen, icemen and butchers’ | tarried to test their marksmanship. little tads of five and six became so exp: with practice that nearly every knocked over a moving target, and had to limit the shots per custome: that all could have a turn. Construction is comparatively simp! you have a small motor and a few pu and shafts from a standard toy structor set. The motor used in the « inal cost only $1.25 and had already) considerable service in other toys. according to these plans, a dupli

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tld last as long as the machinery holds and the only replacements necessary be new tin figures as the old ones be- e battered in service. he amateur marksman will have plenty pportunity to try out his aim with the ving rabbit, squirrel, deer and duck, the bobbing clown. In the center of circular target is a bell for the bull’s- while the row of small disks along front provide several sizes of sta- iry targets. he mechanism is arranged to stop the ‘-hinery when a tin animal is knocked and an electric bell rings when the n is dropped. A hand lever is pro- led at the side to set up the small sta- iry disk targets. Tough woodboard used for the front wall and backstops nd the apertures, amply protecting tender, as BB-shot cannot penetrate it. Make the entire framework, as shown he perspective, of about 3% by 3-in. f, or any similar material you have on nd. A single sheet of woodboard, which mes in standard sizes of 4 by 6 ft., is | for the front face or wall. This runs m 414 to 7 cents per sq. ft. Do not cut windows or apertures for the animals d clown, until they have been properly ited after the mechanism is set up. wever, by following the dimensions en, they will come about as shown in front-elevation drawing. They are t by boring four holes at the corners and ting through with a kevhole saw. Card- ard frames are glued to the woodboard can be replaced when necessary, Assemble the motor and driving mech- anism on a flat board, which later is lo- cated properly on the framework and screwed to it. Although any small motor will do, the photos illustrate the type used in the original. This receives its powet from a lighting circuit through a trans- former, or from a storage battery or dry cells. Do not use over 4 to 6 volts, if an electric bell is to be incorporated. Note the motor-speed reduction through two sets of pulleys and belts and a worm and wormgear. The animals should travel at from 20 to 25 r.p.m. at first. As the marksmanship of your customers im proves, the targets can be speeded up. It is not necessary to follow the exact assem- bly shown if you can arrive at the required speed reduction by any other arrangement. You will note that the four tin animals are supported on the arms of a wood spider, 24 in. in diameter, which is rein forced by a cardboard disk. This spider is built up on two pieces about 1-in.-sq section and halved together at the hub

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320 POPULAR the surfaces will be fl ring A tin concentric contact with the hub, about 4in. in diameter and 3% in. wide, ush. or commutator, is nailed to the spider, with a springy tin strip, or brush, in permanent contact with it. When contact is an an il over, a is knocked made trans- the former, stopping the motor until the gal which shorts lery tender sets the animal up again. cut from first 1e outside perimeter, then cutting to tin ring is easily a sheet by cutting t 1 ] I through diagonally remove the inside portion. The drawings illustrate the details of the animal supports and the manner in which they drop down and form the electrical Insulated from support to hub, are secured to the spider arms in the manner illustrated. T bob- lown a similar de contact. wires, animal he bing c is supported by vice, so that, when he is knocked over, an which. instead formed bell electrical contact is also however, the of stopping the motor. Make the rocker arm for the clown of cedar, white pine or other light wood, and after clown and wir! ire installed, coun rings electric 1o : _ « terbalance it evenly by means of a wood 1 block or weight at the other end, so th: + Lt it will operate with the minimum of powe1 It is actuated by a crank arm to which is attached a link, A large-diam eter pulley at the outer end of the shaft is driven by a small pulley and belt. th a quarter-turn drive, but it runs s | as snuown. crank Arranged according to the diagram, will be very nicely. The wires on the rocker arm the axis so as to im The lo 1 the should lead off near pede action as little as possible. cation of the electric bell is shown i1 photograph. The small disk ‘vets, ranged along board in front, are each cut in one piece, hinged of t the detail sketch. tened with 1 he board, as shown in A single t wire, fas to t ks between ige pin for all, back 1 7 1e bloe Staples the targets, serves as hi and are returned to position simply le. the targets by lifting the lever at the si Although the animal targets in the orig- inal of these drawings remained upright through the entire revolution, until dow nN, aS a prec ution two cardboard disk shot wheels were installed at the right and left of back into pl the large spider to push the animals ice in case they were knocked MECHANICS A wood hub glued the pasteboard prevents these disks fr wabbling on their nail spindles. It much to cut the anim from tin than one might think, provid over by accident. is easier a good pair of snips are available. F lay out the outlines on cardboard, mark into %4-in. squares as shown, and cut o1 with scissors, pa Fairly heavy white ] board should be used. These can then used as patterns for marking the outlin in tin. Each shou and clown have the pasteboard duplicate cement: animal to the front side, as tliis prevents the back from becoming unnecessarily | tered. Ambroid better than glue tl After the pasteboard { pretty well shot up, they « easily be replaced. A flat tin socket is dered to the back of each animal, slip; over the support, and the end of the latt bent Thus the removed. Oil all and is 1€ purpose. are ings over. targets are e bearings, particularly the we wormegear, that In proper conditi the little motor recommended will run entire oad and parts operate freely. see mechanism without over! \ good location for the gallery is just front of the garage doors, where the rage lighting circuit is \] available. the doors provide a rood backstop for wild shots that miss the target complet: Of course only BB-shot and air 1 should be used, though the gallery cot be adapted to. »> 2-caliber rifles by mal the front wall bullet-proof and cutting a job for spe stick to the figures from sheet steel equipment. Better air rifle they are safe, and quite as exciting a others. \bout 24 ft. from the front of the tat place or that pati will be obliged to stand back of it in fi a table counter so Such a counter also serves as a rest for ammunition. distance makes it plenty sporting enou with be iner sased When the wt ip the gallery in | could after guns, cash box and air rifles and can marksmanship improve set of even the gallery, but first lis back yj some the patrons scarcely hour o of practice the moving targets were d! an . + 7 ping at almost every crack. sy charging a reasonable fee for a tain number of shots, quite a little poc!l

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POPULAR MECHANICS 48 col ~~ pee \6°k 12” OPENING 122 SeRQQOI| — ———— +) TARGET BRASS DISK SOLDERED TO BELL SPINDLE ‘OLT TOY MOTOR [DIAGRAM OF DRivING | f MECHANISM 3 ™*— GALV. TARGET 7, HEAVY WIRE STAPLE HINGE PIN-. WOOD OR FIBER - ' ' SHOULDER SOLDERED ON , , \ GALV-IRON \ DISK KEEPS TARGET UPRIGHT c SUPPORT AS IT MOVES IN POSITION SPIDER ARM DETAIL OF DISK- TARGET RACK }

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POPULAR MECH FLAP BENT —_— CARDBOARD CEMENTED TO Dy FRONT ~_ \ TIN SOCKET SOLDERED ON LINK TO // CRANK iF - GALV. LINK Ce METHOD OF MOUNTING 23° g ANIMALS 0 ee Wachee ene rave BELL ba money can be made, and you may be sure your shooting gallery is going to be headquarters for all the neighbor- hood youngsters until something more The more porous the floor, the less exciting bobs up. is necessary. Before applying this ture, the floor must be thoroughly clean¢ with a scrubbing brush and clean wate! As soon as the floor is dry, the solut evenly applied over the surface w whitewash brush. When dry, the is again washed with clean water mop, and after this, another appli of sodium silicate is given as befor Remedies for Dusting Concrete Floors Boiled linseed oil and a sodium-silicate (water glass) solution are two simple rem- edies that can be used, at small and without much trouble and prevent the dusting of expense time, to concrete floors. The linseed oil is applied in one or two coats. It penetrates the concrete and tends to bind the loose particles together. It also prevents water or other fluids from being absorbed. The sodium-silicate solution has been successfully used in many instances. The preparation con- sists of one part of 40° Baume mixed in 3 or 4 parts of sodium silicate water. third coat is given the floor ‘n the manner. It is better, however, to p! concrete floors from them correctly than later. dusting by to apply ren A dusty concrete floor is « by using too lean a mixture in mak by using too little water in the mi by too much troweling of the surfa by permitting the surface to dry ou

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POPULAR For the best kind of floor, use a consisting of 1 part cement, 2 nd, 4 parts pebbles or broken stone ugh water to make a “quaky” After laying the floor, trowel ice just enough to smooth it. If r stands on top, do not use either cement to dry it up, but allow it rate. The floor should be allowed ior a week; no draft should be to touch it, and the temperature be kept as constant as possible. ‘ Flux for Brazing usual proceeding in brazing is to borax to the metal dry, after the is been thoroughly scraped or It has been found, in a large ith’s shop, that a better way is the metal with a solution of boric The advantage of this is that the penetrates every crevice and the surface completely, thereby g it from oxidation. The boric- tion is made by adding quantities id to hot water, allowing it to re- everal hours, with an occasional and then bottling for future use. Coil Spring Removes Obstruction in Sink Trap ppages in a trap can readily be re- by stretching out an old doo} screen- spring until the coils are 4 in. apart mera ; i] 7 SCREENDOOR when re- Turn the spring while you leased. are pushing it into the pipe so that it will screw into the obstruction, which can then be pulled out with little trouble.—Mrs. Re- becca Briekey, Bedford, Ind. » SINK TRAP: made of ellac,8 parts, gum benzoin, 3 parts, mastic, 2 kbinder’s varnish can be parts. These ingre ire pulverized and placed in de alcohol, 50 parts, and oil of lav- part, MECHANICS Neat Arrangement of Shelving for Utilizing Space under the Basement Stairway Use of Space under Stairway homes the under the stairs is wasted, but it can be In many basement utilized for photo. Cleats are frame to hold the shelves. space shelving as shown in the fastened to the stair In Cases where a workbench is located near the stairway, this arrangement has found cially suitable for storing small boxes and been espe cans containing nails, screws, etc Drying and Stretching Curtains Many housewives dry their lace curtains on special frames so that the curtains will retain their shape when dry. A simple method of accon plishing the is shown in the illustration. A ame resu rod is placed in the top bottom hem and the top rod is then fas- tened to the CLOTHESLINE and , clothesline with loops of cord as indicated Several davs before using, the rods should “~|IRON be enameled or varnished in orde1 rusting to prevent them from while in the curtain hems and causing stains, or a regular brass-plated curtain rod can be used

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POPULAR Fine-Mesh Netting Sewed to Edge of Large Umbrella Makes Fly and Mosquito-Proof Inclosure for Campers Shelter Made from Large Umbrella A large umbrella of the kind used by artists at bathing beaches be converted into a comfortable shelter by or can sewing fine-mesh netting to the edge as shown in the illustration. The lower edge of the netting reinforced with cloth tape, and is provided with eyelets so that it can be fastened down securely. It practically fly and mosquito-proof, and as a camp dining room it is hard to beat.— Mrs. R. K. Garnett, St. Joseph, Mich. is is Quick Change from Series to Parallel To change from a series to a parallel connection on dry cells, storage batteries, or other devices, some rewiring is usually necessary, but with the hookup shown in the drawing DOUBLE - POLE, DOUBLE-THROW, KNIFE SWITCH this change can made very quickly merely throw- ing over a dou- be by ble-pole, dou- ble-throw knife switch. Trace the wiring care- fully so that there will be no mistake, and you will find that considerable time can be saved by this arrangement.—Her- man Schepler, Sabula, Iowa. MECHANICS Extended Starter Button The starter button on the Ford : A car is in a difficult place to reac} extension placed on it will bring it enough to permit pressing it w twisting the ankle, the heel of the resting on the brake pedal while t! placed on the starter button extension should be made of iron r¢ is same size as the original and about longer. One end is threaded to fit the top of the starter switch, other is fitted with a suitable butto: accelerator button is good, if one if not, the knob can be off the original rod and welded to tl rod. and obtained: The older cars of this model switch which required heavy pressu This type had a cotter pin thi the lower end of the rod, and an exte1 should not be placed on such a sw close. the pressure needed will bend the time.—E.T. Gunderson, Jr., Humbo Tar-Paper Shields Foil Cabbage Maggots Maggots, which usually prevent cab- bage plants from. thriving, can effectively be prevented from getting at the plants by the simple method shown in the illustra- tion. When the plants are still > a b= | Lieeaces OF TAR PAPER seedlings, a square piece of tar pape 3 or 4 in. in dimensions, is placed ar the stem of each as indicated. A diag slit is cut halfway across the paper hole is punched in the center. Clu the destructive cabbage disease, ca be prevented by applying limestone t soil—C. M. Wilcox, Torrington, ( @A small magnifying glass can be by inserting a strong spectacle len the narrow end of a telephone n piece. The glass is ground on an wheel so that it fits exactly, and shellac is used to hold it in place.

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| pholstered Footstool Simple to Make By HAROLD BROWN (ED to be made from scraps of desired, by curving it down abruptly at rial that otherwise would go to’ the center to form a point about % in. furnace, the shown in the ke a gue inying drawings | = aS rthele ‘ rerv .* WALNUT xiL” rtheless a very be gy coonmeienl ind attractive furniture. Since le from the small that accumulate WALNUT 2” (2 REQUIRED) LavouT »N $” SQUARES home shop, the ' ide from the tri- — os FOR END TACKS 3 PLY on WOOD (2REQUIRED) pense of the tap- ‘overing, is practi- nothing, and the in be knocked to- MORTISE in an hour or two. CORNER DETAIL + bv 14-in. pieces quired for the ends While the specifies walnut, any good hard- ll do equally well, and even good lay be pressed into service. Pine, s especially effective if the piece used in a room furnished in the style. Lay out the design for ona piece of stout paper marked Lower Left, Footstool, Upholstered in Tapestry; Right, -in. squares. It will be found Finishing a Curved Surface with the Spokeshave to lay out if only half the design is high. Lay this pattern on the wood and then the paper folded along the trace around the edges, or else stick it to line of the design and the two the wood with rubber cement and use it cut out at the same time, thus keep- as a pattern for sawing. It can easily be h sides symmetrical. The straight peeled off afterward, and the cement ng the bottom may be modified, if cleaned off with gasoline. The wood is sawed out on the bandsaw, or, if this is not available, with a turning or coping saw, and the edges smoothed with the spokeshave and sandpaper \ quicker method of finishing is with a small sander drum mounted on the lathe. The rails are 20 in. long, of 4 by 14%- in. wood, rabbeted, as shown, on one edge on the jointer or with the circular saw. This rabbet takes the edge of the cloth covering and the tacks that hold it. The edge that is exposed outside the cov- ering should be % in. wide to match the thickness of the ends. On the ends of each rail, cut a %-in. square tenon, % in. long: these are later glued into mortises cut in the ends as shown in the drawing. Note that the mortises are cut on a line iwing the End on the Bandsaw; Left, Assem- . ‘ 7 1 the Footstool, Showing Tacking Piece with the angle of the top line of the ends 325

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326 POPULAR MECHANICS Coat the tenons with good glue, drive on the top, gradually drawing and them into the mortises, test the assembly ing it in and filling up any uneve1 for squareness and clamp until the glue’ until the general contour of the has set. Cut two curved pieces of %-in. contorms to the curve of the piece wood to the shape shown, and glue and totheends. Then lay on the cloth s brad them to the endpieces between the for covering and fasten it temy rails. These are to take the end tacks’ with small tacks. When you have holding the covering. Cut a piece of sure that the pattern runs evenly, t three-ply wood to fit between ends and padding is uniform and that the ck side rails to form the top. The edges been stretched with even tension, d: should be cut at a slight angle, to make ishing tacks, 2 in. apart, all arouw a neat fit with the side rails. Glue and edges, removing any exposed smal brad the top in place. Coat the ends and as you proceed. The cloth shou rails with walnut stain and, when this is turned under \% in. all the way dry, give them a thin coat of shellac. After so that the tacks go through a 24 hours, sand the shellac and coat with thickness. Place the rails on a fir: clear varnish or lacquer. When the var- face when tacking, so as not to nish has set for 48 hours, rub down with the joints, and, _ using long fin pumice and rubbing oil, if a dull finish is — tacks, drill a small hole for each ta desired. A fine gloss can be brought back, fore driving it sei to avoid sj after the preceding operation, by rubbing the wood. The holes should be with rottenstone and oil. two-thirds the length of the tack s The upholstering is a simple matter. finishing gimp may be used unde: Lay several thicknesses of cotton batting tacks, if desired. Atomizer for Spray Painting the brass coupling from the pum, ; and also discard the rubber bulb Good results obtained with the use of atomizer. It will be found that th spray-painting outfits can be duplicated fits nicely on the atomizer, and al on a small scale with a similar outfit im- have to do is to fill the glass conta provised from an ordinary perfume atom- with lacquer or paint. The cont izer and an automobile pump. Remove _ forms a natural handle while the Auto Pump and Perfume Atomizer Make a G provised Spray Gun for Painting ana Sten is operated with the other hand. The fit has been found excellent for lacqu small articles and is especially suital use with stencils in decorating fur and making signs. To control the a of lacquer passed by the spray, un the container and pinch the end «

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POPULAR MECHANICS pipe slightly to- is indicated, until rs the exact spray If much spray- » be done, a pint yp can should be ted for the glass r, and the supply ust then be length- ith a piece of thing that is forced it it will be held tion How to Keep Tools Free from Rust eep tools clean and rub a little mer- ointment over hich will form a \re-resisting coat- his ointment is hat poisonous, so be handled care- \nother good mix- keep tools from is made by heat parts of lard and Use of an Electric Lantern Submerged under Water Will Attract Fish and t of rosin together Increase the Catch intil the rosin is all melted. The Submarine Lantern Attracts Fish of the mixture should be done open air to avoid danger in case Lowered from the and benzine added in about the submarine lantern show1 tion of 1 pt. to % Ib. of the mix- has been found to attract When cool, the mixture is rubbed It consists of a truit jar through the top over the tools, which will resist of which a hole is drilled for rubber rosive action even of salt water. covered electric cable. This nnects to he inside of the jar and rv cells kept in the boat rhe a 4-volt lamp on t lew coll Old Pipe Distributes Seed to three d cable is cemented with waterproof cement distributing seed evenly, an old in be used to advantage. First re- | at the point where it passes through the id. Che object is, of course, to increase move the mouth- the catch—Jas. E. Noble, Toronto, | piece, scald the ; pipe bowl in hot water and allow to in Weight Keeps Clothesline Taut dry for two days. By running a clothesline through a Then puttheseeds number of swivel pulleys instead ot tying in the bowl. By _ it to hooks, as is usually done, and pro tapping the pipe viding a weight at one end, the line will be gently the seeds kept taut. Of course, the other end of will drop out the line must be securely tied and the as desired. For very small seeds weight must be heavy enough to counter the mouthpiece.—Geo. H. Holden, balance the wet clothes.—Cliff Deal, Santa ‘rheld, England. Ana, Calif.

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328 POPULAR Cut-Outs Make Shutters Attractive Beerry ; | Gene 4 | Cut-Outs in Window Blinds Work with a Scrollsaw Artistic Involve Little Cut-outs of shown in the photo, make window shutters more attractive. A stencil is made to a design to the panel, and a scrollsaw ts then used to make the cut-out. It has been found best to paint the shutters white so that the cut-out will show up in contrast to the dark background behind it—H. Rossiter Snyder, Guilford, Conn. various designs, as transfer Easy Way to Grind In Faucet Seats Brass faucets are often scrapped cause they leak, although they are still condition be repaired. The new faucet may be $3 or $4, whereas, be- of a with a little emery, ordinary and a round stick of hardwood, the faucet seat, which may only have a small dent in it, can be quickly re- ground, after which it will as good asa cost an brace be new one. The hard- wood stick should about 10 in. long, with one end cut down to fit into the jaws of an ordi- nary brace. Remove a valve bonnet and stem and whittle down the wood until it fits loose enough into the faucet to allow be MECHANICS it to turn easily. The end to be use grinding must be flat and true. Firs ply some coarse emery, about No. 80, a little water, and proceed to worl stick back and forth with the brace i: same manner as the valves of an aut bile ground. Lift the stick occa ally and drop in small pinches of emery. Frequent examinations seat should be made. As free from dents or deep cuts, repeat operation with some very fine eme: remove any scratches made by the c emery, after which the faucet cleaned out, and reassembled washer.—R. W. Tillotson, Eric tor are oO! soon as is oughly anew Baseboard Blocks Save Bedroom Walls It frequently happens that bedrooms are the wall scarred through being repeatedly by the corner of the be the bedpost. To prevent this damag tach a block of wood to the baseb: about 6 in. above the floor, that bed will hit the block instead of the SO Mailing Tube Makes Good Desk _ half an Cut in lengthwise, ordinary mail- ing tube has been found useful as a desk tra Semicir- cies ir pieces of PARTITIONS —+ wood are fit the and are tacked in place to form ends and parti Small rectangular pieces same stock are then tacked to the end serve as feet.—L. P. Young, Culver, I: 14 -in. " HALF OF MAILING_ cut TUBE to inside tions. ot Charcoal Deodorizes Refrigerator One of the most effective raethod eliminating undesirable odors which sometimes characteristic of many ele refrigerators, is te keep some charcoa the food chamber. A tea ball filled fresh charcoal every two three wi will absorb all traces objection odors and will prevent the resulting | taste in butter. or of

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POPULAR iopperdoser” Is Used to Exterminate Grasshoppers the mid-west where pers cause considerable damage to one of the most effective methods exterminating them is by using horse- Yn pans containing oil, as shown in Such a device is called a pperdoser” and consists of a shallow States, grass- drawing. pan, mounted on low sled runners, a curtain or shield at the rear. The usually made about 2% ft. wide and rigidity being obtained by ing the edge of the metal over and lering in partitions to brace it. The is filled with a mixture of water and to a depth of 2 or 3 in., and is then vn through the fields infested with the cts. The curtain or shield is made of long, rip of oilcloth, the glazed side facing pan. As the device is drawn along, insects take alarm at the passage of horses and immediately rise. A large rcentage is caught by striking the cur- n and then sliding into the pan below. lany are able to leap out of the pan, but e covered with a film of oil which kills i very short time. It is quite ual to “harvest” bushel baskets full of e insects in a single day. The oil used x the purpose may be kerosene or old obtainable at garages, the vners of which are usually glad to co- em ina ankcase oil perate with the farmers in exterminating he pest. Although this device seems rather vkward, its use has been found highly tisfactory.—C. A. Lovell, Hutchinson, Drawn through Infested Fields, This Pan Containing Oil, Exterminates Grasshoppers MECHANICS Slotted Supports for Scaffold Are Slipped on Perma- nent Lagscrews in the Wall Scaffold Supports from Angle Iron For washing windows, the scaffold illus- trated is much handier than a stepladder. Two large lagscrews are permanently lo cated under each window or pair of win- dows, the heads of the screws projecting just far enough to engage with the slots cut in the scaffold made of angle iron supports, which are In use, the supports are hung in place and the board laid over them, affording worker.— V. * a safe platform for the McMahon, Chicago, III. Preventing Silver from Tarnishing Silver vases, trophies, loving cups, etc can be protected against tarnishing and the consequent necessity of frequent pol- ishing by the following method: Ordinary househole gelatine is soaked in cold water and dissolved with heat to the consistency of thin sirup. To this add monium or potassium bichromate to give ulhcient am alight lemon color. The objects are dipped in the solution and allowed to drain and dry in bright daylight. Due to the ac 1 tion of the bichromate, the gelatine hard tough, invisible film, from dust can be ens into a which readily wiped, but which prevents tarnish. The effect will be found permanent.

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NTENDED for the advanced m maker, who wants something m realistic in the way of power for ship than the conventional rubber-ba motor, this eight-footer will give the c structor a real thrill. It demands a c tain amount of skill and a lot of “flyi sense,” but tests have shown that it real flyer, considering the fact that use of compressed air for powering m planes is as yet in its infancy. With actual 8%-ft. wing spread, the pl veighs only 22 oz., complete with mo and tank. The motor used is a comn cial three-cylinder type which can be p chased either complete or knocked d at a very reasonable price. The tank may eithe: made by the builder or purchased from the same sou of supply as the motor. In building this model, start by cutting out the wi ribs, 42 in number, exactly like the template sho The ribs, made of medium or hard balsa wood, measu 11 in. long and about 1% in. wide. First cut a full template of thin material or cardboard. A good met! of making a number of ribs exactly alike is to lay o 4 SQUARES CROSSBRACE 1 SIZE OF WOODEN FORM O? WHICH TO MAKE AIR TANK - 44 the shape on WING AND OUTRIGGER- BEAM SLE EVES | Pp i ece of 1 14 ARE SHOWN IN SOLID BLACK . balsa, about 2 wide. Make t curved cuts 01 ee ee ' jigsaw, if one Part Plan and End View of the Skeleton Fuselage and Wing Section; Above, Rib cine tnd oe Section Laid Out to Scale avaliable, an

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FoR THIS he piece length- n “46-in. widths on rcular saw. The cut- can be made later, care should be en to keep the ribs 1uch alike in size, ht and balance as a ble. When sawing he ribs on the jig- allow a little clear- so that the ribs be slightly over- then sandpaper m down to the exact lensions. Square tches are cut in the erside to take the ter, Assembled Center Section of Wing Showing nk Cradle; Below, Front View of Tank, Engine, Propeller and Landing Gear n spars, and a V-shaped notch is cut the front, as indicated, to take the spar rming the entering edge of the wing. \iter all the ribs have been completed, the center wing section, which is 22 in long, can be built up by gluing the ribs onto the spars with ambroid cement. The spars should be “6 in. wide and “6 it thick, and the ribs are spaced apart as in itl dicated in the plan view entering Glue on the and trailing edges, the forme: being ‘46 in. square, and the latter meas uring 46 by % in. Crossbraces of %4 by 4%-in. balsa strips are then fitted snugly and glued in place. The two end ribs are reinforced with a cap strij material, glued onto greatly increases the streng sembly. The end ribs are set in about 8 at the top, so that the side sections of the when wings, butted up again this in clined edge, will have the proper dihedral angle to obtain the required stability for the ship. When set in place. the tip of each side wing section will then be about 6 in above the underside of the cente:

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POPULAR wing section. The joining of the wing up in detail later. [he next thing to do is to build the side sections will be taken sections, tollowing the same procedure as just described. make which is A common mistake 1s to y alike, they should be hand. TI 1. apart and t forced } +1} ‘Ae tt swactliy potn Sia sections e@xactty wrong; ht and left ribs } made ri: y ~ ) 1! e are end fi by “ap strips. spaced he are reil of 15-in. baml again \ piece .00. in its width as it entire comes, is bent over a candle flame to torm the wing tips, the piece being split to size after bending. The best position to hold the bamboo is with its shiny from the flame. directly over tl side farthest Do not hold the bamboo ie flame, which will burn it, but on the side of it. The slip spars for the wings are “6 by S46-in. pieces of pine glued to the sides of the balsa sp: extend about They are cut the irs, for about 5 in., and they 5 outside of the wing. to dihedral in. a shape corresponding to angle of the wings as These Photos Give a Good Idea How the Entire work Is Constructed and Assembled, and How MECHANICS shown in the detail between the plan a end views of the model. The slip sp fit attached to the section spars in corresponding positio1 indicated in solid black. into sleeves cente as hese slee can be made up of .015-in. aluminum, | to fit the spars, or built up from pine in. thick. The fit snug. A using should be moderate cradle for .O15-in. the c dle being cut and bent to the shape dicated in the plan and end views. Dor use any felt in this socket a will have a tendency to slip. Ambroid used the the wor the fit fairly tight. T] stabilizer built up like but has an inverted cambe the underside the tank must be bu sheet aluminum, cloth or to fasten cradle to Be sure that tailpiece or 1s is small swing, that is, is curved instead The exact shape of t side of the tailpiece i the top. he curve $s not important. T! entering edge is % in spar is ¥% by ! square. The fir 1 in., and the iQ 1in., second % while the trail Bat boo is used for making t ends and tips, edge is 46 by % in. he pier t ‘ being bent to a half cir The rudders are made of thin pieces of bamb: Lay out the form and then in fi size bend tl! Frame- the Center Wing Section Is Clipped to the Tank

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POPULAR MECHANICS iboo to the pe. By bending wide ‘es and then splitting m, it is an easy matter make them alike. The hed pieces used for king the rudders should be about The rudders are glued to the as shown proper “eo 2 1n. side of the outrigger spars, one of the photos of the stabilizer, and aluminum outrigger spars fit into a pair of eeves attached to the long ims, which are in turn held in sleeves vided in the center The out- ver beams are the only supports hold- section. the stabilizer to the main section of e plane. [he center section of the wing should covered with silk, a thin grade of China k being used for the purpose. For the her parts, use Japanese bamboo tissue 9. This paper is very light and the yngest kind for its weight. After the ng sections and stabilizer been vered, the paper and silk are given an pplication of dope. The silk-covered ction will stand one or two heavy coats. have light coat of banana oil will be sufficient the paper. Spring sheet brass, .006-in. thick, is used making the tank. The brass is rolled ound a cylindrical wooden form, slightly tapered toward one end, as shown in one the drawings. Make the tank 36 in. ng, 2% in. in diameter at one end and the other. The sheet he tank is laid out on a smooth table or bench top, then wrapped snugly round he form, allowing 4% in. for a lap, which ust be soldered. Do not use any acid, but only a good brand of paste which is guaranteed not to corrode. Also be sure » tin the edges carefully before solder- n. at brass for ——— i they will not adhere otherwise ing, as which can easily be done, as it is tapered. Tank heads of the shape shown are then made After soldering, remove the torm and soldered on, and an air valve is fitted in the rear head as indicated. wire, .O1 in. in diameter, is wrapped around the tank the full length, spacing the wire 4g in. apart and soldering it in place on two sides. In soldering, be sure to keep Thin piano far enough away from the tank seam so that it will have no tendency to open. At the forward end of the tank, a provided to control the air supplied to valve is the motor. at a model-airplane supply house. Get some brass tubing, } his valve can be purchased 16 1M. iti inside diameter and *42 in. outside. Three lengths of this tubing are to be passed directly through the tank to sleeves for holding the ends of the landing gear. Drill %o-in. holes through the tank at points diametrically opposite each other and sol- der the sleeve in place. serve as The exact posi- Se — - — Side View of the Plane, Showing the Point Where the Wing Fits the Tank; How Piano Wire Is Wrapped around It, and Where Landing Gears Are Attached

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334 POPULAR tion is not material, but they should be placed about as indicated in the side ele- vation. Put a pressure of about 40 lb. on the air in the tank and submerge it under Finished Plane Covered with China Silk and Japanese Tissue Paper water to test for leakage. Gradually in- crease the pressure to 90 Ib., testing occa- sionally as you go along. The landing gear is made up of Me-in piano wire, bent to the shape shown in the photos. This wire is a little hard to han- dle. but has enormous strength for its size. The joints are wrapped with tinned music wire and are then soldered. One piece of wire is used for the rear-wheel frame. Allow about % in. at the ends of the frame to clip into the sleeves or sockets passing through the tank. Care should be taken, when mounting the motor, to get the shaft straight in line with the line of flight. making the propeller, or a propeller can be purchased ready-made. One can be cut from a block, 14% by 1% by 15 in., be ginning the cut about 2 in. from the center of the hub. When finished, apply two or three coats of dope sanding the surface carefully each time. The of the tank and the fuselage is facilitated by the use of rubber bands. Put all the tail parts in place and sight it for a final line-up. The finished plane should balance about one-third the distance from the front of the leading edge of the wing. The necessity for a 6-in. dihedral on each side is to prevent sideslipping. lf model sideslips, the wings are likely to hit first on landing. However, with the proper dihedral, the plane will usually come down on the land- ing gear, which is made sufficiently strong to sustain the shock. Start out by making a number of low glides until the plane is correctly balanced, Balsa is used for assembly a MECHANICS and then give enough air pressure to tu the propeller over rather slowly. Try lengthen the glides in this way and crease the propeller speed gradually ur a good flight is made. It should be ke in mind that this model be us roughly and therefore good care must cannot taken to avoid breakage. Preheating Camp Stoves A little daub of “canned heat” jel affords a cleaner and hotter flame for heating the of camp than does the ordinary gasoline. found camp fire, particularly A convenient to canned hea so that it is instantly ready for use, is fill a collapsible tube with the jellylil substance. re generator sto It starting a in wet aid in also be a great weathe | way carry An empty shaving-cream tul will serve the purpose. The tube is ‘olled, opened at the bottom, shaped in a cvlinder, thoroughly cleaned and filled with canned heat. The bottom the tube is then folded several times crimped tightly, and heat can be carried in convenient forn T I il a supply of canne Outboard Motor Propels Two Canoes Two guides, appointed to transport t canoes loaded with camp supplies a d tance of 20 miles, reduced the labor + ti minimum by lashing the canoes toget! and mounting an outboard motor betwes them. A piece of 1%-in. board was lashe across the bows and another across t . sterns, making a sort of crude catamara Xs The trip was made in a short time.—A fred Elden, Portland, Me. a Two Large Canoes, Lashed Together, Propelled an Outboard Motor ie. ae }

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TES ASN Zia(aw, J 1h Nw Py Portable Bench Saves Mechanic’s Time By DICK COLE [ |svaees a garage mechanic takes drawings show how such a bench may undreds of steps a day between his easily be made, at small expense 1e stockroom, the toolroom and the The chief item required is one-half of a rkbench. Many of these steps can be rear-axle assembly from a junked car, ed and greater working efficiency at- the full-floating type being preferable. d, if several completely equipped The differential end is bolted to a substan- kbenches are provided for the shop, tial wooden base, which may be of hex hat the mechanic not only can have agonal shape, as shown in the illustra- 1 t} is tools, but most of his materials, tions, square or circular, as desired. Four beside the job. The accompanying heavy casters are fitted as indicated. To LOCK WASHERS, COTTER SPRING CLIPS PINS, ETC. ; (em J = DRILLS Instead of Taking the Job to the Bench, This Bench Is Taken to the Job; It Carries as Well as Tools, and Saves the Mechanic Many Steps

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POPULAR MECHANICS sheet steel or cast iron over a fire to | vent the fumes from reaching the wo o"x 12" Watch the steel carefully while it is be cHARDWOOD | heated, and as soon as it has turned t purple or blue, quench it in water rub with oil. You can then use a scril on it to make lines which will sh plainly, and it will not be necessary to so careful in handling and machining TIGHTENS BRAKE BAND” _if tool.—H. K. Ellis, Cincinnati, Ohio. Hardening Scraper Edges When the edge on your scraper will 1 hold, or you have an extra-hard piece metal to work on, re-dress the tool a: harden it as follows: Heat to 1,450° F to a nice cherry-red, then push the Cl ; « > — e nla . = rell, support the hexagon-shaped bench top, "8 edge into a cake of common yell . : SO; ‘ . ‘ 4 3 > 1%4-in. square hardwood stretchers are oap to a depth or about 2 in. Let bolted to the face of the wheel. These remain there until it has cooled down should be about 20 in. long a black, and then quench in water at abo 20 in. long. es tons =r A hexagon box is fitted on the bench 60° F. Thi will give you a glas na top, and triangular partitions, running edge which is tough but not brittle. from this down to the corners of the top, ——— divide the bench into six compartments. Protecting Sucking Pigs On the sides of the box, in each compart- \¢ : gail Often a mother sow will accidenta kill some of her offspring by lying them. One method of preventing thi ment, containers for such commonly re- quired supplies as nuts, washers, cotte1 pins, ete., are built, as well as for drills, reamers, wrenches, and similar small tools. At the edge of one bench compartment a vise is mounted. The brake-band mechanism can be left in place on the wheel, and an extension rod with a thumbscrew on the end may then be used either to lock the bench to the standard, or to release it and allow it to be revolved. Three or four heavy wedges, carried on the base and driven under the bottom when required, make the whole outfit stationary for vise work. - Ledge of 4 by 4-In. Stock Protects Young Pigs f: Being Killed by Mother Sow Coloring Steel for Layout & y to attach 4 by 4-in. beams to the ins walls of the pen, about 7 in. above floor as shown in the drawing. I ha found this arrangement an effective sa guard for the little pigs, as there is ple: of space for them to crawl under the p: very careful not to touch it, to avoid eras- _tecting ledge —C. M. Wilcox, ing the lines. I have found a good ton, Conn. method of eliminating this worry. Block — out the steel in the usual way and clean @[When an inner tube is immersed it well with a piece of emery cloth. Then water to find a leak, make a mark arou place it in a furnace, or put a piece of _ the hole with an indelible pencil. After a piece of steel has been blocked out to the proper size for making a tool or a die, and is then coated with prussian blue or venetian red so that the scribe lines will show up clearly, one must be Torri

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POPULAR MECHANICS LAWNMOWER DISPLAY FOR STORE WINDOW Electric Fan Rotates Blades of Lawn- on Display in Hardware-Store Window ething that moves always holds an tion in a show-window display, es- v if the source or cause of the mo- innot readily be determined. The ¢ shows a window display of a which utilizes the draft of air 10-in. electric fan for turning the A specially ard, plywood or sheet metal con- the draft from the fan and directs nst the upper portion of the mower from a position behind the machine. fully note the shape and construction ‘ box, which does not only serve to the draft but also to hide the fan ew. If desired, wer, ribbons may be at- Push-In Handle for Snap Gauge purpose of the handle shown in rawing is to prevent the snap gauge being pushed too forcibly on the which soon destroys the accuracy gauge. The handle is movable in a hole drilled in the gauge and carries a square block, which is ccurately made to a slid- ing fit on the gauge. Thus, if any attempt le to force the gauge on the work, and check it, SLIDE BLOCK ick will slide forward constructed box of tached to the stationary parts of the mower, but these will betray the presence of a draft. If the blades will not readily, loosen the stationary knife as re- quired, then, to make the blades turn still easier, remove the dogs « on the end of the turn knife shaft. put on the tion to a A good grade of bearings to minimum. reduce but will not move if the gauge is tried on the work with ordinary because the work then offers less resistance to the gauge jaws than the block.—Harry Moore, Hamilton, Can pressure Brown Stain for Mahogany When staining mahogany, it is times rather difficult to get a rich without a slight reddish hue. If hue is not desired, some- brown such a try the following solu Mix 1 pt. of walnut stain and % pt of weathered-oak Apply with a brush enough to cover the work rapidly and evenly, and then wipe off the surplus stain with a cloth.—L. H. 3uffalo, N. Y. tion: stain. wide Georger,

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38 POPULAR MECHANICS EXPERT TELLS HOW TO SLING LOADS FOR SAFETY When a sling is used to lift a load hav- ing sharp corners, it should be protected against being cut by means of pads of ae fs ene 4 LAG~y a) y Le" UNSAFE HITCH burlap, or, better still, wooden corner chains of equal length, with rings at pads. The sling should be sufficiently long ends, make a good sling. The four to leave a considerable space between the may then be held together by mean top of the load and the point of suspen- larger ring engaging the hook, or the 1 sion. The point of the sling hook should rings may be engaged directly witl never be inserted in a link of the sling, hook. For special kinds of work, spe throwing all the strain on the point of the chains should be used, such as b hook. The hooks are not designed fot slings, etc. Besides taking care ni such service and the point may be bent pass chains over sharp edges without open or broken by this practice. Sling ing protective pieces, chains shoul chains should be provided with one or free from knots and twists. The more large rings to engage with the hook should be lifted gradually, as a or else the chain should pass through the © strain is likely to snap the chain belly, or saddle, of the hook. Che best Fliegelman, Worcester, Mass method is to use an endless chain, wrap ping it around the object to be litted and ] th . - ; Measuring Screw Threads passing the top of the sling through the belly of the hook. If an endless chain is The old method of measuring not available. use a chain having a ring with a pair of broad-nosed ca at one end and a hook at the other. By over two or three threads h: passing the hook into the ring it will serve to the better plan of measuring the purpose of an endless chain. Two down the sides of the thread. Meas

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POPULAR MECHANICS , gives the outside diameter, but eads should fit on the sides and not , and bottom. The bottom of the depends entirely on the point of ‘-ading tool, while the top depends ‘ther the cut is brought up so as to sharp in a V-thread or to the right f flat for the U. S. standard. But ng the sides of the thread tells tory. Of course the most refined curate measurements are made by e of wires laid in the threads, or th a special thread micrometer, but e work, grind the points on a pair pers so as to touch the sides of the about halfway down, and then re a bolt that has the proper thread Using this as a standard, you will prised to know how accurately you threads, if the angle is kept right. Waste Holder for the Garage waste can be conveniently held in a iiner made from a 2-ft. length of pipe. Triangular pieces are cut out lower end and the remaining sec- re bent inward to retain the waste. metal straps, screwed to the wall, he container in position. In use, iste is removed through the bottom, irned-in edges making it convenient out just the quantity required. Vaste Holder, Made from a Length of Stovepipe, Is Handy for the Garage Adjustable Extension Leg, Fastened to Ladder with Clamps, Can Be Used on Uneven Ground Extension Leg for Ladder Painters and ethers who use ladders will find the illustrated extension leg use- ful on uneven ground. Two flat-iron guides, bent to the shape shown in the detail, are bolted to each leg, to receive a sliding piece, which can be clamped in place with thumbscrews on the guides. Pipe Nipple Aids in Starting Wood Screws Often it is difficult to start a wood screw straight because it wabbles under pressure of the screwdriver. A _ helpful device in such cases is a short pipe nipple of which the inside diameter is just large enough to slip over the end of the screw driver and over the screw. In use, the screw is placed in position and the screw driver, with the nipple slipped over it, is then engaged with the screw, after which the nipple is dropped down over the screw. Hold the nipple with the left hand while driving the screw home with the right 1 hand.—John E. Hyler, Peoria, II1. @ When scouring steel cutlery, use a cork instead of a cloth; it will wear longer.

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Tool for Cutting Strips For cutting uniform strips of material, such as leather, the adjustable-gauge Adjustable Stop on Knife Aids in Cutting Uniform Strips of Material knife shown in the drawing will be found handy. It is homemade and consists of a short blade riveted to a shank which is bent over at right angles and driven into a suitable handle. A_ strip of flat metal, with a slot cut lengthwise in it, is either soldered to the shank to which the blade is attached, or riveted to it with the same rivets as the blade. The slotted piece is bent over at right angles and a stop is pro- vided which can be slid along and tight- ened at any point with a thumbscrew. Aids to Lubrication of Ford Some of the grease fittings on the model-A Ford car are not easily reached by the hand-pressure gun furnished with the car. Since some owners wish to do this work, a few changes will prove help- ful. The nipple on the lower steering- spindle bushing is hard to reach. One of the 65° drive nipples, such as are used on the upper bearing for the spindle, may be installed here and will make lubrication easy. The fitting on the front end of the drag link is also in a hard place to get at. 340 POPULAR MECHANICS A 65° threaded fitting should be turne in and left pointing upward. The versal joint takes quite a large amou grease, and should have a pipe exte: applied and run forward on top of the m tor-support arm under the hood. rear-wheel bearings should have 65 90° threaded fittings screwed in wit] openings toward the rear. Because the large fenders, the spring shackle rear-wheel brake shafts are hard to r without going under the car. If | wheels are removed, they can be reache by the hand gun without going wu The only places now left under the car the two nipples on the throw-out through the clutch housing, which are all of the cars. Some cars have one each pedal and one on each end ot cross shaft for the hand brake. Whe filling these, it is best to go under th: from the left-hand side. Traveling Chair Aids Workmen Certain tasks in factories can often better performed when the workman seated. However, in cases where it is essary for him to move along the be the traveling chair shown in the pl will be found convenient, as it ca rolled along on a track. A ready chair can be adapted to the purpose using only the seat and backrest, chair can be made to suit the requ ments. Four 4-in. rollers are attache the underside of the seat to fit the t: The latter have strips of 1-in. wood na to the sides and projecting over the to keep the wheels on the track Seat on Rollers That Will Slide along the Entire | of the Workbench ( uni it er ne E ee

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POPULAR MECHANICS 341 e SPRAYING TALL TREES IS EASY WITH THIS RIG of rder to reach Lee. yps of tall ~<“SR*< vhich had to rayed, the il- , 4 or ed rig was useful. It of nsists of a long

the wagon to project vertically. To raise the hose nozzle for spray- ing, a %4-in. rope is run over the pulley and tied to the nozzle as indi- cated. In this way, it nd r pole, to the is easy to adjust the cl pore hich a spool nozzle to any height de- the ot pulley is at- sired. The angle of the er ta L. rhe lower nozzle is controlled by ler end of the pole is moving the hose as re- ure tied to a length of quired—Elmer Huf- ? 4-in. stock, ferd, Rushville, Ind. is nailed to

Tree-Spraying Hose Can Be Raised to Any Desired Height with the Aid of a Pulley, Rope and a Long Pole Rigged as a Light Derrick, on a Flat-Bed Wagon Which Carries the Barrel and Pump ( Satin-Finishing Aluminum hands, as this makes stains. The frost- ing is accomplished with a fine, soft steel- atin-finish aluminum, buff the arti- wire scratchbrush, about 6 in. in diam e if necessary in order to obtain a good eter, and running about 2,500 r.p.m. New ‘e, and clean off the grease in ben- brushes should be broken in on coarse Then dip it in a scalding solution work or by running them against a file. ‘t potash, not too strong, until the ‘e is dull and white. Rinse in cold and soak for 5 or 6 minutes in a r-cent solution of hydrofluoric acid Ordinary transparent lacquer used for ‘ften the surface. Then rinse again coating brass and other metals can also ind dip into a mixture of equal parts of be applied to paper reference sheets, ta and sulphuric acid to remove the _ bles, drawings, etc., to protect them from Protecting Drawings

oration. After this, rinse again in being soiled by handling. The lacquer is id water and in clean hot water. poured into a shallow tray, and the sheets ry the article in sawdust of good quality are dipped so that both sides are thor tree from pitch or gum. Boxwood oughly coated, then hung up to dry. The rch sawdust should be used if possi- lacquer covers the paper without affecting Care must be taken not to touch the’ the printed matter, and it toughens and Lengt num at this stage with the bare glazes the surface.

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boca ANS made up and wired, many a owner with a modest purse dos feel that he can afford one and does without, buying a more o1 satisfactory substitute. However, knows how to handle a glass cutter soldering iron, he can make a very star lamp himself. It is not very mu a job to do this and the work affor interesting pastime. If he does not to cut the glass himself, he can, fo: than five dollars, buy a complete out! knocked-down form, including the s ing jigs, so that all he has to do is to s the pieces of glass together and wir lamp. Almost any kind of glass that the 1 l NUSUALLY odd and attractive, the fancies can be used. An antique twelve-point star lamp shown here, is having a light olive-green color, ha just one of those ornaments that help found especially suitable. This car make your home distinctive. obtained at the larger ¢ Although lamps of this kind — . and paint stores, or | can be purchased already Oe concerns that handle ~ glass work. As each i of the lamp is made vy five triangular piece glass, 60 pieces will be quired. Fifty-five of _ ~~ | \ ) Souveren - =I To POINT | FLAP FOR SOLDERING, AT JOINT)" | re! SOLDER 7 Benn | ~~ CUT OUT, SHEET-COPPER : FRAME FOR — HINGED POINT

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Sigg in the form of true triangles ac- to the dimensions given in Fig. 2, ie other five have the narrow end < cut off as indicated, so that, when bled, an opening is left at the top e insertion of a nipple which holds rht socket. Obviously, this point re the uppermost one on the lamp fixture ring at its end provides a of fastening it to a chain or other ° e correct method of cutting the glass wn in Fig. 1. Hold the cutter ver- using a straightedge as a guide. the cutter in turpentine ke it bite. It requires i bit of care to cut the or rather to break it off along the scratch made he cutter. For this rea- is a good idea to prac- n scrap pieces of ordi- window glass until you Completed Star Lantern Is Shown at the Upper Right, Used over the Bottom of a Stairway get the knack of doing it with lit- tle or no break- age. After all the glass has been cut, the edges must be bound with cop- per foil or very thin copper shim stock. This should be about % in. in width for or- dinary single-thickness glass. If the glass is thicker, it will be necessary to use wider strips. Before bending them over the edges, cement should be applied, which can be made by melting together a lump of beeswax, about the size of a hickory nut, and two tablespoonfuls of fir or Can ada balsam. After the mixture has cooled it should be rather hard, yet noticeably 343

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344 POPULAR sticky to the touch. Without cement it is impossible to make the foil adhere to the glass. A good method of applying the Over a flame, warm up a metal plate, which is at least é in. thick, in order to hold the heat. Two or three sheets of newspaper are laid on the plate and the foil is then laid on the paper. Melt the paste and apply a thin coating to the foil with a brush or piece of rag. Lay the foil with the coated side down on an old magazine, and cut it into strips of suitable width with a sharp knife, as shown in Fig. 9. Next put the strips on the edges of the glass. cement is as follows: gas In doing this, it will be noticed that by repeated bending, the foil become hard and brittle. In this condition it easily broken and to restore the copper to its original it must be annealed, which is done by heating to a cherry-red over a small alcohol lamp, as shown in Fig. 10, and allowing it to cool in the air. If the metal is so stiff that it will not bend easily or lie flat, follow the same pro cedure of annealing. Care should be taken to get the foil applied as evenly will is softness, around the edges as possible, so that it will project about ‘ Fig. 3 shows a piece in. on each side. of glass completely bound and ready for soldering. A soldering jig, for holding the pieces in their respective places for assem- bling, consists of five short strips of wood tacked to a base to form the sides of a pentagon or figure of five of glass MECHANICS equal sides. Fig. 4 gives the exact ar- rangement and dimensions of the jig, and Fig. 5 shows how it is used. The copper bound pieces of glass are placed ag the blocks on the jig, so that the « of the pieces will butt toget evenly. Be sure to have the pieces glass together so that, when viewed fror outside, there will be a V-shaped cl which is later filled with solder. D let the edges overlap, as this throw points Apply a little solder paste and first “tack” two pieces toget Then the remaining three pieces on in the way, so that all five pieces will for unit that from t without risk of coming apart. It is necessary to apply flux before dering in order to make the solder a the metal. A good paste flux used instead an acid flux, a latter is corrosive and will, in time, « through the copper foil. The point, is now only tacked together, must be « pletely soldered. To do this the po held in such a position that the edge | soldered is perfectly horizontal, per ting the solder te be run in the For a | askew. at two points along the edge. can be removed to be ot evenly. purpose jig will be fou It sists of a base convenient. two pieces of nailed angles, as show Fig. 8. The ape the point is p on the hig block, while base set the short block on at 1S ag

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POPULAR MECHANICS es as a stop and prevents the point | slipping out of horizontal. The oves between the adjacent edges of are then filled with solder, using a difficulty in doing it. After being cleaned, the points are assembled, which is done by tacking the base edges together at the This permits the points to be corners, SHEET-COPPER HINGES SOLDERED To BOTTOM heavy pointed iron. \pply the solder oughly at first and then smooth it off, drawing the iron from the point to the ase with a slow, steady movement. Re- ember not to hold the hot iron against he point any longer than is absolutely ecessary, or the glass will crack. Also, irge drops of melted solder coming in mtact with the glass are to be avoided r the same reason. After the outside edges have been finished, the inside edges re carefully gone over. Usually it will be found that more or less solder has run rough from the outside eeds to be run smooth. \fter all twelve points have been fin- hed separately, the inside of each point ould be thoroughly cleaned with a rag turated in and merely gasoline or other cleaning uid. Do not postpone this job until the mp has been partly or completely fin- hed, for you will then have considerable OF TOP POINT “ae BRASS WIRE ~~ SOLDERED TO JOINTS r ~ HINGE DETAIL twisted slightly in fitting them to ad- jacent points. Some assistance may be necessary in getting the first three points together accurately. As previously mentioned, one point has its end cut off to allow the insertion of a nipple to which the light socket is attached. The top edge of this point must be covered with copper foil in the same way as the other edges, and a nut soldered on. A keyless light socket is wired and a 2-in nipple is screwed into the cap nut. The wire is first run through the point from the inside, and the nipple is then turned into the nut so that it projects about 4% in. on the outside. The top ring nut is then screwed onto the projecting nipple Figs. 6 and 12 show the method of assem bling these parts. he socket in place before soldering the top point Be sure to fit to its neighbors, or you will have difficulty doing it later. provided An opening must also be This is done by hinging a point adjacent to the top one, as shown in Fig. 13, so that it can be swung up to get at the interior for inserting a lamp.

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346 The weight of the hinged point will keep it shut. The hinge pin is made by solder- ing a piece of stiff brass wire to opposite sides of the point, and the hinges are formed from two strips of thin sheet cop- per, bent around the pin as shown in Fig. 14. A frame for the hinged point or door is also required. This can be made by bending a %-in. strip of sheet copper over at right angles throughout its entire length, after which it is formed to fit the base of the point. Fig. 7 shows how this strip is notched at points 2% in. apart, to facilitate bending, and how the ends are cut out to make a smooth joint when fitted together. After the frame is finished, it is , dered to the five ad- a4 jacent points, ‘| around the open- ing. The door point is inserted into the frame and the hinges bent around and soldered to the side edges of the point containing the FACEPLATE — 4— - ‘+ STEADYREST — - — sol- COLLAR — POPULAR MECHANICS to remove soldering paste and fingerma: The soldered edges will be shiny at but will soon become dull and will t! closely resemble lead. There are m uses for such a lamp, a few of which shown in the illustrations. It is especi suitable for hallways, vestibules, pore and may even be used for a bridge lamy Truing Work in Worn Chuck When operating on particular work with a three or four-jaw universal chuc! that is out of true, the difficulty can remedied without using shims, as folloy Place a piece of tubing, having an inter: diameter suitable to the work, betwee: the jaws, and tighten them up equally, so that the tubing will be bent slightly out round. Bore the tubing out to the siz of the work. Then insert the work and tighten the jaws, and the work will ru perfectly true. The tubing will not tu in the jaws.—J. Harger, Honolulu, H Crowning Large Pulleys in a Small Lathe When about to crown some pulleys | large to swing in a lathe, which was 1 equipped with blocks for raising the h¢ and tailstocks, the method illustrated \ employed. The pulley was pressed on arbor of sufficient length to accommod a steady rest and a straight-tail dog on t end nearest the faceplate, while the othe: end turned on an improvised center con sisting of an angle iron set on a blo bolted to the lathe bed. A cast-iron co lar, bored to a running fit on the arbo was clamped in t! steady rest to for a bearing. A bi was attached to t! faceplate to drive the dog. As tl center of the fa plate was lowe than that of t work, it is evide that the bolt on t faceplate wou slide along the ed lamp assembly, as shown in Fig. 13. After the lamp has been completed, clean the outside with a gasoline-saturated rag of the dog wh driving it. This, course, gave a variation in the speed the work, but that was not important.

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POPULAR Cleaning Greasy Clutches e of our heavy derricks, which was e cone-clutch type with wooden fric- blocks, caused considerable trouble the blocks not taking hold when the ers were operated, because oil had satu- d their surface. This trouble made juent renewals of the blocks necessary. appened, one day, that a lighted match carelessly thrown into the machine, ting the oil. To extinguish the flame, operator used the fire extinguisher, ch was filled with a solution of car- ) tetrachloride. In doing this, the so- tion was also squirted over the blocks. hen the machine was again used, they took hold as if new, the solution having olved the oil on their faces. A large n of the solution was then used to clean e friction blocks whenever necessary. he solution has also given good results cleaning greasy automobile clutches nd oily brake bands. It is much better in gasoline or kerosene, and, of course, iier than these, because it is not inflam- able—A, S. Jamieson, Springfield, Mass. \ Repair for Rawhide Gear \ rawhide gear can readily be repaired if one or two teeth have been worn or broken. The nuts and end plates hold- ing the assem. bly together are first re- Repaineo oved. The lavers of raw- hide are then pried apart and rearranged so that the layers containing the worn teeth are staggered across the width of the ear and distributed over its entire periph- When assembled again and bolted gether the gear is nearly as strong as a one.—E, N. Davey, Vancouver, Can. LLL / ATLL LHEN MECHANICS CHISEL RACK These Handy Racks Will Hold Tools Securely, under Heavy Vibration Tool Racks for the Workshop For holding files, punches and chisels, the racks shown in the illustration have been found highly satisfactory. A hori zontal shelf for the files is counterbored on the top at regular intervals, and a slot is run to the center of each counterbore. The tools will not readily be dislodged by vibration, as the handles are seated in the counterbores. The punch and chisel rack has a shelf arranged at an angle with two strips of 1 by %-in. wood running along top and bottom, these being notched to hold tools.—G. H. Cappel, Wilmer, Ala. Drilling Hardened Steel I have iound the following method for drilling hardened steel very satisfactory: The pointed end of the drill is ground to a half-round shape, then made as hard as possible. The surface to be drilled is with diluted muriatic acid. In- stead of oil, turpentine or kerosene, in which a little gum camphor has been dis- solved, is used as a lubricant. Should the bottom oi the hole become polished, so that the drill rides over it, remove the drill, etch the bottom of the hole with the acid and proceed as before—Wm, J. Ed- monds, Rutland, Vt. etched

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POPULAR Arrangement by Which Old Windmill over Dry Well Is Made to Operate New Well Sunk Eight Feet Away Old Windmill Pumps New Well After an old well ran dry, a new one was sunk about 8 ft. away. windmill over the new one involved too great an expense, so a double walking beam was improvised, which made it pos- sible for the windmill to operate the new well efficiently. Moving the The beams were made ot hardwood connected and pivoted with links of heavy flat iron, while a_ mill plunger rod was pivoted to the end of the outer beam and to the pump plunger. A crosspiece on the windmill was used to pivot the first beam while a sturdy pole braced to the windmill served to pivot the second beam. All details of construction and assembly are clearly indicated in the drawing.—Dale R. Van Horn, Nebraska. Lincoln, Changing a Ball-Bearing Fit A bearing had to be ground out to fit a shaft that could not be turned to fit the ball bearing. The construction of the bearing was such that it could not be taken apart, and it had to be held in the grinder by the outside raceway, which or- dinarily would leave the balls and inner race free to turn. As wedges would force the inner race out of true, I decided to try MECHANICS a filler. The bearing \ laid on a faceplate paraffin was poured the space between balls. After cooling, paraffin held the ballsa inner race securely that the bearing could chucked and ground the required size.—| nest Romkee, Colorad Springs, Colo. Hinged Miter Box Can Be Swung Out of Way Many workers who have limited space their workbench, wil find the hinged arrange ment of the miter box convenience, as it can | swung out of the wa when not in use. A large butt hinge is fastened | one end of a piece of 2 by 6-in. stock which the miter box is mounted, and the bench top. In order to insure rigi ity while being used, the miter box mu also be fastened to a loose end. bench top at This is done by means of thumbscrew slipped through a hole the miter-box base and then drive: through a nut soldered to a plate, which fastened to the underside of top as shown.—John E, Michigan. ben Flin the Bostow, NUT SOLDERED » TO PLATE Hinged Miter Box Can Be Swung Out of the Way When Not in Use

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POPULAR MECHANICS Balls in Brake Drums Cause Noise e rear wheels of my car were equipped external contracting brakes, which iced a peculiar shrill hum, similar to ieging band, when a speed of 15 miles hour was reached. Repairmen, who ted the brakes for me, predicted that would cease as the ehness of the band had worn down. vever, the noise continued, so I had wheels removed. Inside of the brake m a number of hard balls, amalga- ted from road dust, rust and oil, were und, the largest being 3% in. in diameter | weighing nearly an ounce. The balls re removed and the wheels then re- ced, after which no more trouble was ountered.—Elton Sterrett, TY la. noise soon as Savannah, Handy Soapstone Holder he illustrated soapstone holder is a shop nvenience of proved merit. It is made rom a piece of sheet brass, bent to form a ectangular tube. The adjoining edges re soldered together, a slot is cut down h corner and the ends are bent inward form jaws, which hold the soapstone tightly by means of a ring. When the ring is slipped up the jaws are released. The top end of the holder is closed and fitted with a coil spring to exert pressure on the stone, elimi- nating the trouble of pulling it out as it seph Chmelar, St. Louis, Mo. wears.—]Jo- Truck Transports Boxes Horizontally For transporting heavy boxes in a hori- ntal position on a shop truck as shown the drawing, two hooks are attached the handles. The hooks are pivoted to ‘handles and the lower ends are bent to the pan grips. As most of the pans in shop are of one size no difficulty will experienced in fitting the hooks to 349 them. In use, the truck is lowered until the hooks can be engaged with the grips and the truck handles are then raised to Shop Truck Has Hooks for Lifting Heavy Pans in a Horizontal Position lift the pan from the floor.—F. C. Weg- ener, Indianapolis, Ind. Milling an Accurate Keyway When milling a keyway central within .0005 in., as in gauge work, precise meth- ods must be used. It can be done by first cutting the keyway in a piece of scrap stock to see whether the cut is the right and then centering inthe cutter in the following man- ner: A surface gauge and indi- cator are used on both = sides of the shaft, the slide of the milling ma- size, INDICATOR cross SURFACE GAUGE chine being ma nipulated until the readings are exactly the same on both sides. rod As the surface-gauge with the shaft, it a stop.—George Shabach, Phila- delphia, Pa. comes in contact acts as

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POPULAR I Homemade Circular Gasket Cutter Is Adjustable Adjustable Gasket Cutter For cutting circular gaskets, the tool shown in the drawing has been found use- ful. It steel center rod, equipped with a handle and ground to a point. It is drilled to receive a horizontal rod which holds a circular cutter, the latter rod being kept in position by a set- screw. A suitable handle is, of course, also provided on the horizontal rod. In use, the tool is adjusted to cut a circle of the desired diameter and while the cen- ter rod is held with the left hand, the cutter is rotated with the right.—G. L. El- well, Amenia, N. Dak. consists of a Ledge on the T-Square Many draftsmen and artists who con- stantly use a T-square, will find the illus- trated ledge for holding pencils, erasers, etc., of considerable utility. It can be made by groov- ing a piece of 1- in. stock of the desired length and attaching it to the with screws, T-square small taking care not to crack the wood. No matter at what angle the board is held, the groove will keep the pencils from rolling off. Of SECTIONAL VIEW MECHANICS course, a similar ledge can also be p vided on the lower edge of the draw board.—August Jeffers, Bedford, Ind. Obtaining a Smooth Finish on Soft Metals When milling, planing, turning or oth: wise machining a tough metal that ha tendency to drag and tear, such as copper: aluminum, bronze or babbitt, a smoot finish can be obtained by keeping the su: face of the metal flooded with benzin: provided, of course, other factors of workmanship are not at fault. Roug! finish on these metals is usually caused by the small cuttings sticking to the surface and getting caught between the tool a: the work.—H. K. Ellis, Cincinnati, Ohio Simple Brace for Speedy Driving of Screweyes Sent to the shape shown, a length of steel rod makes a good speed wrench for driving in screw- eyes. The end is bent at right an- gles to the shank to insure a good hold on the screw- eye, and the crank section should ex- tend far enough to afford sufficient leverage. Lights of Automobile Draw Insects Away from Tent Insects have the habit of gathering a campers’ tent during the day and thx cause considerable distress to the occu pants at night. A net over the open prevents them from entering at aight, b it is rather difficult to keep them out wh the campers are going in and out duri the daytime. A good method of elimin ing the trouble is to remove all the lig from the tent as soon as it gets dark, to turn the headlights of the car towa the tent opening. Open the net over t doorway so that the insects in the te

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POPULAR eadily get out. They be attracted by the lights and, after a t time, every one will the tent. Light can be brought into the again and the net closed.—Harold E. on, Denver, Colo. Starting Small Brads model der I have often been fronted with the blem of starting small a scale- or tacks in places cessible with a ham It is, of course, pos- ‘to drive such brads the aid of a nail set, in doing so, much MECHANICS bo ~ 12g" —4 a + HOLE DRNLED ° FOR £STEEL PIN _, rig 3 ar : of re a5 ty“ commen ee STEEL JAW, 2 REQ oss e is often lost owing the difficulty of hold- the brad in position til it can be started, and unfortunately a directed blow often has deplorable con- However, this trouble can lily be eliminated by using a piece of n. drill rod, about 5 in. long, ground it at each end and then magnetized. uch a nail set will hold the brad firmly any desired position until it is driven place. To magnetize the rod, stroke from the center to one end with any ignet, or lay it across the two poles of an equences. WORK lagnetized Nail Set Holds Small Brads in Position in Places Inaccessible with Hammer tromagnet while the current is turned Harold T. Bodkin, Chicago, Ill. The Cross Braces of This Vise Hold the Jaws Parallel No Matter How Far It Is Opened Improved Woodworkers’ Vise Keeping the jaws perfectly accomplished in the parallel is illustrated means of two “lazy-tong” braces of flat iron, each pivoted at the top as indicated, while the bottom end is free to slide up and down in slots. vise by Both crosspieces are pivoted together at the center. Hardwood this and iron plates are fitted in the grooves to take the thrust of the lower ends of the crosspieces is used in the construction of vise wear on the used, but a cast-iron wheel has been found more useful than a handle. as the and avoid wood. An ordinary vise screw is vise can be closed and opened more quickly with it. Carefully follow the construction, as illus trated, duplicating the dimensions, which are taken trom a vise in actual use Use Old Brushes for Painting Concrete Brushes wear out rapidly when used for painting cement and concrete. If a new brush is used, it will be found practically other work For this reason it is a good idea to use your old brushes on cement and concrete, thus sav- ing new brushes for work that demands a better finish.—L. H. Buffalo, New York worthless for any Georger,

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POPULAR “Petrified” Logs Made of Concrete Imitation Logs Made of Concrete Finished and Painted to Resemble Real Logs In order to prevent the earth from washing down the paths of his terraced garden, a neighbor of mine called in a Japanese cement worker to put in some curbing. The worker suggested concrete logs and the result is shown.in the photo. Along the sides of the walk leading to the arbor, and at the base of the terrace, he arranged a row of stones. These he cov- ered with a heavy coating of concrete, forming logs of various sizes. To make the imitation as realistic as possible, even the bark simulated, scaled off in places, and the surface was then painted in wood tones and lichen McCrae, Pasadena, Calif. was shades.—Lee Lubricating Derrick Sheaves It is almost impossible to get the aver- age derrick operator to oil the sheaves at the top, as it is necessary to climb the mast. On an 80-ft. derrick, this difficulty was overcome by running a %-in. pipe along the mast, to within a few feet of the top, and fitting a length of flexible metallic hose on the end to reach the cen- ter pin of the sheave. Metallic hose comes in sizes appropriate for this purpose, to- gether with the necessary fittings, which are a solder nipple on one end and a \%-in. pipe-thread nipple at the other. At the bottom of the length of pipe, an elbow, taken from one of the high-pressure au- to-greasing systems, was fitted. A good MECHANICS grade of grease, that does not harden in cold weather, was used, the entire pipe being filled by means of the high-pres grease gun, so that, at any time af ward, a push on the gun below forced grease into the sheave pin. of lubricating has also been found p: ticable on all clamshell buckets on the derrick engine. In places wh: the nipple was likely to be broken off old oil cup on the bearing was remo and a solid plug was substituted for Another plug of the same size was drilled and tapped to take one of the grease nip- ples. To oil the bearing, the solid pl was removed, the with the nipple screwed on, and the grease gun applied This met one Keeping Water Can on Tractor After I had lost two good 5-gal. water cans from the tractor platform, which was caused by their slipping off and then being run over with the plow, I decided to fa ten the next can in place so that this would not happen again. A couple oi harness rings were wired to the fender and a length of light rope, fitted with a snap at one end, run around the can, end of the rope being tied to one ring per- manently, and the snap be- Was one ing engaged with the other ring, which permitted quick detachment.—Will Smith, Thief River Falls, Minn. Helps for Home and Shop YOU CAN MAKE IT—One hundred il’ ustrated cles telling how to make toys, furniture and doze1 other things from old boxes and odd pieces ot lun Price Ten Cents. POPULAR WOODTURNING—Especially written for the amateur, this book should be in the kit of ev home-workshop owner Price ‘Twenty-Five Cent MODERN HOME INTERIORS—Crammed tu suggestions for the home owner who likes to make own built-in conveniences. . Price ‘Ten Cents Order any of the above from The Librarian, Pot Mechanics Magazine, 200 E. Ontario St., Chicago closing the proper amount in stamps or Coin,