Popular Mechanics 1928-08: Vol 50 Iss 2

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POPULAR MECHANICS MAGA = “ >" > —. * WRITTEN SO YOU CAN UNS=SSST, 4 REGO TRADE MARR GRLAT MIAN we #048

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~ E. C. ATKINS & COMPANY Established 1857 426 S. Illinois Street, Indianapolis, Ind. Leading Manufacturers of Highest Grade Saws for Every Use; Saw Tools, Saw Specialties, Plastering Trowels, Machine Knives, Grinding Wheels and Files Sold by first class Hardware Dealers the World Over AT YOUR eacarer 3 fie Hardware Store Uk: ANE e we

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age Popular Mechanics Magazine 200 E. Ontario Street, Chicago, U.S. A.

H. H. WINDSOR, Founder H. H. WINDSOR, Jr., Editor and Publisher London: Hachette & Cie., Paris: Hachette & Cie., Melbourne: Gordon & Gotch 16-17 King William Street, Charing Cross, W.C. 2 111 Rue Reaumur 509-513 Little Collins St. ISSUED MONTHLY SUBSCRIPTION: SINGLE COPY, 25 CENTS In United States and its possessions, also Canada, Cuba, and nae, per year, postpaid - $2.50 To all other countries in the Postal Union - : - - - - 3.00 All subscriptions are discontinued at expiration. — examine do dams printed on your wrapper. Entered as Second Class Matter Sept. 15, 1908, at the Post Office at Chicago, Illinois, under Act of March 3rd. 1879 Entered as Second Class Matter at the Post Office Department, Canada Published monthly by POPULAR MECHANICS CO. Copyright, 1925, by Popular Mechanics Co. Copyright in Australia. Copyright in France

Vol. 50 Contents for August, 1928 No. 2 Special Features Travel of the Future PL ee , Scacaage atkeena 194 The Unsung Heroes... oe (ead eucee ieee Half Around the World in Sixteen Days at 210 Muscle and How to Use It - javephanees oes 219 On the Trail of the Swindler - om 242 Training Circus Horses....... Cor aerror ee ern The Latest Mystery of the Heavens * ante ee Modern Wizards of Water Magic ‘ ‘i ~ 274 Man’s Law on the Yukon .._.... ee ; + 291 Agriculture—women farm experts in Sumatra 193 Bottle—glass tube in cork serves as funnel 214 Airplane—ninety-foot tri-motor for transatlantic flight. 280 Bridge—stone arches replaced by steel span 250 Amber—rich mine gives work for entire village 272 Cake—in form of skyscraper weighs half a ton 285 Amusement Park—coin-in-slot swinging seat 254 Calking—automatic gun leaves one hand free 206 Anchors—mushroom, to hold landing fields at sea 279 Carpet Sweeper—with combs to keep brushes clean 294 Archzology Catnip—as lure for bobcats helps protect game 279 man’s antiquity evidenced by new finds 249 Chimney—felling giant, shows skill 289 probing the tomb of first artist of all history 230 Clock Architecture—home in side of cliff for movie stars 239 buzzes warning of engagements 284 Army Training—war game with model map 288 thermal motor winds, as temperature changes 200 Astronomy—telescope with giant lens 264 Coal—gases from smoke may cause colds 256 Automobiles—glass hood permits view of motor 246 Concrete—wire-carpet form improves cement floor 264 Automobiles—Accessories , Corn—husks used to polish rubber 294 clasps for skid chains simplify adjustment 238 Crime clock like speedometer withstands shocks 236 portholes in windshield help in bandit chase 207 clock on gear lever replaces knob 215 two-wheeled forts aid police war on bandits 248 extension rim on wheel helps travel in mud 193 Currency—seek longer life for paper 281 glass protector keeps windshield clear 281 Diving—queer suit to reach greater depths 224 handle on steering wheel is aid to driver 208 Door—with bronze grille guards against burglars 255 jewels on license. bolts increase safety 249 Electric Lights—giant bulb for special purposes 273 light with magnet base 255 Electric Signs—changeable, made up with loose lamps 290 mud clamps for tires prevent sticking 271 Exercise—apparatus for neck promotes health 295 posture pad promotes health 256 Explosives—tons shipped without loss of life 284 Automobiles—Driving—steering wheel turns lights 295 Fenders—for desk save silk hose : 278 Automobiles—Equipment and Supplies—rubber bump- Fertilizer—apply with hose while watering lawn 200 ers guard car and passengers 209 Filling Station—umbrella-top has automatic gong 257 Automobile—Tires—spring to hold valve cap 273 Fire Fighting—tests with chemicals help reduce losses 280 Automobile Truck—electric cooler helps motor shipping 223 Fish and Fishing Aviation aquarium tests show fish answer call to food 248 air-rail passenger routes to speed traffic 254 minnow net comes apart for easy packing 236 Britain’s bid for the world’s air capital 251 Floods—seven-ton concrete braces help curb 27 improved neon arc light to aid 296 Fruit Squeezer—fits on table and saves time 254 international aero station 234 Geysers—rain and snow feed ; 288 plane rigged for blind flying to reduce night hazard 218 Giraffe—“‘skyscraper"’ cage needed to ship 241 seaplane to carry hundreds over ocean in few hours 290 Glaciers—tell their secrets in clockwork “diary 256 three hundred air schools show growth 250 Glass Eyes—require blowers’ highest skill 224 Bed Glass, Optical—big disk tested at night to reveal defects 232 folding, fits in dresser drawer 288 Golf that gives comfort on hot nights 208 dummy as instructor shows proper form 240 Bees—honeycomb fifty feet long found in house wall 265 grip guides, for players help improve game 233 Boats and Boating—big motor boat like torpedo for Hats—changeable styles, decoration for porch posts 279 transatlantic trip 216 Hedge—accordion cutter leaves smooth edges 207 Books—made to talk” to the blind 265 Helium—new plant for military dirigibles 273 [Continued on Page 4]

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[4] [Contents—Continued] Hosiery—how to tell fashioned from imitation Hot-Water Bag—has electric heater Household Devices House Plan Insurance—patent, protects inventar and maker Ivy Poison—effective chemicals for Kettle—gives whistle signal when food is cooked . Keys—case with swivel hook : ea Land, Reclaimed—yields big crops Lawn—renovator to clean, reduces hand raking Locomotive—burns gasoline and speeds switching Lumber—shipped in packages to save waste and time Machine, Recording—for store helps tabulate sales Milk—kept fresh by iceless cooler Money—armored car observatory helps guard Mop—self-wringing, solves carrying problem Motorcycle three-wheel-brake sidecar promotes safer riding. three-wheeled travels rough ground : Moving Pictures apparatus for retouching film lessens eye strain . exhibited on airplanes huge liner as studio affords realistic scenes strap holds camera for steady pictures Neckties—electric press for helps preserve fabric Ocean Depth—over seven miles shown by echo measures Parachute—fin for jumpers aids safer descents Phonograph—unit for making own records . Photography four-lensed aerial camera to speed mapping photograph made on steel with high explosive Piano—child’s playing guide simplifies instruction Plants—cabbage and radish crossed Plow—for flat-bottom ditch makes ne sides Purse—keeps coins sorted Radio combination a.c. and d.c. test set handy program index reducing local interference Radio—Aerial antenna protects building .................... building a telescope antenna Radio—Amplifier—-an inexpensive push-pull Radio—Applications as alarm to waken people low-frequency waves to help treat disease microphone aids teachers as well as pupils . portable loud-speaker set aids foremen Radio—Batteries charging from d.c. supply old auto generator as charger Radio—Coil—has twin rotors Radio—Installation—soldering lead to lead Radio—Loud Speaker make this > wll drum practical kink for cone Radio—Pictorial Radio— Receiver detector circuit without B-battery five ways to electrify your set good tuning devices important tables for electric sets Radio—Reception—reducing power-line pick-ups" Radio—-Repairs handy testing points ; test points from phone plugs Radio—Rheostat—safety stop for screw-in Rays, Ultraviolet—reveal tooth cavities Razor “parking’’ space for blade prevents cut fingers safety, thick blades last indefinitely Refrigeration—gas flame keeps fish shipments frozen Rowing—practice with mirror helps train oarsmen Rubber—chemical prevents oxidation of Rugs—experts say life is fifteen years . Safety Devices and Measures—electric hand si sig- nal protects pedestrians Sand—pictures “painted’’ inside bottles Sculpture—sculptor works six years on war memorial. Searchlight—effectively reproduces northern lights . Ships and Shipping passengers put in basket to board steamer rudder as high as a house guides big ship wireless-controlled battleship Shoes—modern “‘seven-league boots’’ afford high speed Silk—artificial from coal Sisal—substitute for gasoline from Skyscrapers—“‘air rights,”’ built over railroad tracks Spoon—on metal bottle cap aids in taking medicine Stamps—coin-in-slot dispenser for post office Steel—made without furnace in new electric process Stereopticon—“‘spirit”-picture projector to aid teachers 201 238 . 286 . 352 279 216 250 . 285 209 . 240 217 249 218 284 301 311 311 306 311 233 281 Submarine Giving BEE 10 G08 1p TORCHES... 0.0 cnc cee sseais. greater safety through improved design Gree at hee Swimming—skiff as life-saving unit affords sport . Table—extension set saves space in small rooms Telephc ges to ships, planes and train by dial __ system Pipes aay: Tides—highest on Atlantic coast Tools shears and punch in one save use of drill square for cutting rafters aids roof builders Tortoise—raised in desert to supply food Trousers—without seams woven in hand loom Typewriter—for the blind has six keys Violin—with straight sides is easier to play Washer——crown, to hide screws and nuts Welding—electric, promises noiseless building age AMATEUR MECHANICS Airplane—for “Lindy Junior” Automobiles—shock absorber for the trailer Basement—lock for the trapdoor Canoe—pipe frame on auto holds Dogs—portable heated house Gun—spring, from old umbrella Hogs—scalding and hanging Leather—to preserve old : Lock for sliding windows remote-control electric combination, for sliding door Molding—improvised plane for making Moths—trap for catching night Paints and Painting cleaning brushes staining wicker furniture Photograph Negatives—removing emulsion from old Photography—use of pack films in cut-film magazine Porous Plaster—to remove from the skin Refrigerator—more space in Screen—making a Chinese Sink—how to clean a stopped Target—that saves air-rifle bullets Tools—improvised strip cutter Tricks—can you do it? ‘ Tumbler—homemade holder Vegetables—sprayer and drain for _. Vermin—protection against Watering—system for hedges and terraces Me Weather Vane—three wise owls make pease Windows—to open high, swinging : SHOP NOTES Automobiles—cementing gear-shift lever ball Automobiles—Accessories—convenient location for tool Automobiles—Repairs—how to remove a broken spin- dle bolt Barrels—truck for carrying aged Bearings—how to cool hot : Bees—jug trap for ; Boxes—of varying height handled by adjustable tote- box truck Cow—to prevent switching tail Dividers—with bent points for marking centers Doorplates—artistic, beautify home Garage—build your own Garage—Equipment and Supplies—seat f for auto greas- ing attendant : Hogs—watering trough for. .... ............. Hydrogen Sulphide—oil-seated valves for . Ink, India—how to use in fountain pen Lathe—spring center for... _..—_................. Measuring Can-—adjustable, for the shop . Milk-Cooler—spout shifts automatically Paints and Painting—adjustable scaffold for painters Photography cure for slipping tripod washing prints in the kitchen sink Poultry—wire basket helps turn eggs in incubator tray Pump—locking clamp for pipe Reamer—non-reversible holder Rope—homemade machine for making Steel Wool—for oilcan strainer Stove—moving the kitchen range Tools copperplating small : device for lifting heavy work on bench Tubes, Brass—forming small, bent 313 337 341 339 340 338 347 350 340 337 347 338 351 347 346 336 343 . 339 339 345 351 346

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©} Popular Mechanics Magazine +4 Vol. 50 AUGUST, 1928 No. 2 ae 4 } g ’ } 4 319 20 nths in Bottles of Water to Each of Which a “Plant Rose Cuttings, without Roots, after Growing Four Months it Have Developed Good Root Growths Pill’”’ Had Been Added; the Cut Ster ; 339 By H. H. DUNN 350 1™ ATEUR eardeners mav throw away larly short time, indoot ll the year d - ‘ ‘ | ides and forks, trowe 111 aroun teri pots, and produce their own No 1] required, no vomiaalcaal Pie gms flowet month in the year, in window eeded Phe re boxe n cans,*or any other recep p ot the f 339 tac hold \ ter. In a box. tl t Ou ) l : f se l ( lit ry ip tine ou c : 347 indo ] li ad zen rose cuttings clipped to be optained rom tne ive re 350 , . ae ‘ _ idatieen dace dental —- 340 from the parent bush in August, will sup- at small c compare one 337 ply blossoms for the Christmas table. or cut flower t 34 . , —— | , Me weeds ereeinn ee ] Sweet peas, planted in jars in the tern [his wonder worker amo 338 box on October 1. will provide abundant the product of some sevet eal 347 bloom New Year’s day. Dahlias, zin Dr. W. F. Gericke, of the Univer 336 nia ister chrysanthemums, pansies, California More that 20) varietie 343 phlox, tocks, or whatever tlower one de plant numbering nearly 2,000 ind dua 339 Pee 339 sires, may be made to bloom in a sim have been ma cle » p

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steel—made without furnace in new electric process Stereopticon—“‘spirit’’-picture projector to aid teachers 233 281 178 POPULAR soms at any selected date, indoors and out, at the university. In addition to flowers, any other plant which is bed to garden or field, can be so controlled by transferred from seed starting the seeds in water containing the 1 Th pill. Thus, be made to produce virtually all vear. J ; , indoor vegetable gardens can But the greatest value of the discovery, as so far applied, is in the production of flowers for the home in defiance of winter temperatures outside. The normal warmth at which most houses are kept during cold weather is ample for the growth and blos- soming of the plants under the urge of the chemicals in the pill. In the case of roses for the home indoor are from. the bushes in August, or other summer month, and placed in two or one-quart garden, cuttings taken any glass jars, as space may allow, or in tin cans. The open top of the jar is cov- ered with a cork or cardboard, cut to the shape of the jar, through which the stem of the cutting is passed, permitting the lower end to rest on the bottom of the device for lifting he Tubes, on bench bent avy wt rk Brass—forming small, MECHANICS jar, the top, with its leaves, extending well up into the open air. The jar is then filled from half to three- quarters with water, and the height of the water marked on the outside of the jar, so that it can be maintained by additions as evaporation and absorption lower the level. The water is never changed, merely added to. Either before in the water, the pill is being sufficient for each through blossom. time. quired for root growth or after putting dropped in, one plant up to and ‘he period rc- and blossoming for more than 200 varieties of flowering plants, and varies materially, the range being sixty days to nearly six months. Rose cuttings which have been planted with the pill in August will be ready for Christmas cutting. for Novem- ber should be made in July; those for Jan- uary, in September; for February in Oc- made later where winter is has been calculated exactly Cuttings Cuttings than October. in regions not tober, and so on. severe, will produce blossoms so quickly, nor of such large size, as those Nine Weeks’ Growth of Columbia Roses from Cuttings Eight Inches Long; No Part of These Flowering Plants Has Ever Touched the Soil, Despite the Well-Developed Roots 351 346

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351 346 POPULAR taken from April to Oc- tober These cuttings, vhich have blossomed vith the help of the plant pill, may be transplanted to the garden in spring- time, and have been found to be tar ahead of other plants of the same kind and age originally rooted in earth. Annuals, such as sweet peas, zinnias, asters, pan- ies, and many others, may be controlled and made to blossom at any

time in the same way. The seeds are planted, either in the ground, at midsummer, in shaded seed boxes, and, at trans- planting time, transferred to the water jars contain- ing the plant pills, or, if (oe soil tacilities are not > available, on the flat sur- face of a piece of cork, floating in the water in the jar. There they sprout, and the first root- lets get immediate benefit from the solu- tion. Sweet-pea vines, five and six feet in height, loaded with blossoms, have been grown in sixty to ninety days by this method, the longer period being for those whose seeds were started in the earth.

HOOK TO STRAIGHTEN FENDERS REDUCES REPAIR COSTS To remove the kinks in damaged fend- ers, a steel bending bar with a hook at one end and a self-leveling leather-cov- ered pad and hook at the other, may be used by almost any- one, it is reported. The close-bent hook is designed espe- cially for straight- ening up the fender flange, while the other end makes it easy to pry the fender away from

a ike at, >, c's J a | F,

MECHANICS 179 Globe-Shaped Building Exhibited at German Exposition; the Nar- row Base Will Permit the Building of Wider Streets, the Architect Believes \ - HOUSES IN FORM OF SPHERE TO AID TRAFFIC Streets much broader than are per- mitted at present can be laid out by mak- ing the houses and buildings in spherical fashion, as shown at a recent German ex position, the architect who originated the design declares Means for better venti- lation and lighting and a !ess obstructed view from various parts of the structure are also provided. The model house was ninetv-eight feet high, eightv-two feet in -_ d ametel and rested On i base ixteen | one halt leet le the tout ( r t< n vere devoted to bu ess OTnCce Phe upper part contained l restaul and cate ind in out ol bal skeleton a . COoOnY ie

the tire. Removing Kinks in Fender Flange with Straightener of the building was ol teel.

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POPULAR MECHANICS Pitching the Rasta Beach Tent and View of I Open, Showing Roomy Interior ONE-PIECE TENT FOR BATHERS EASY TO PUT UP Weighing but a few pounds and fash- ioned in one piece, so that it can easily be folded up and carried, a tent for the beach provides effective shelter from the sun and winds and may also be used as a playground tent. The top “jackknives” and folds in a operation, the material is furnished in attractive strips of various colors. single and FRONT-WHEEL DRIVE ADAPTED FOR PLEASURE CARS Front-wheel drive, developed with suc- cess for racing, is being tried out in Europe for pleasure and commercial cars. The advantages of driving through the front wheels instead of the rear ones out- weighs the mechanical difficulties of trans- t t | mitting power to steerable W heels, engineers believe. The chief advantage claimed is that the power is alwa being trans mitted in the direction in which the ca moving, When a rear-drive car | turns, the propulsive force is bet Y exerted in one direction, while the steerable wheels are turn ing it in another, a fact that 1 responsible for upsets when high speed turns are attempted. An- other advantageous fea- ture 1 that the absence of the propeller s] alt and reat axle dif- ferential makes possible a much lower- hung body The front-wheel drive cars turn easily, instead of f to continue 1 straight path, and « ough roads the front wheels pull themselves over obsta- cles, instead of digging into them. One disadvantage is encountered on a steep hill with a slippery pavement, fo1 the greater ; / portion of the car's weight is then thrown , 1 on the rear end SILENT BUTLER ANSWERS DOOR AT PRESS OF BUTTON Duties of a servant are duplicated in an electric door announcer devised for the convenience of the home owner and the callel the Answering a summor! it the door, occupant of the house simply | presses a button which flashes an electrically lighted sign reading, “ “ro dition the an- i to show a green sig nal, one moment please” or, be down in a minute.” In ad- nouncer is set “in,” if the person is at home. A red “out,” is displayed signal, if the occupant is not at home. The attachment is not difficult to install, is rather tive and occupies decora- but little space on the door,

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POPULAR MECHANICS 181 ELECTROCUTING PLANTS AS AID TO MEDICINE Plant in electric chair es Normal position 4 of arm 4 , if Position of arm | i Vy with cells } i contracted | Hi b. ? + Mirror Lamp Movements of light to left reco; jeat truggies of plant aiailahariaaiiameaeiar naman arene aw Rapid movement increasin First as plant is killed g movement twitches Movement in Plant Recording different phases Pulse of onimal heort — of animal omer 7% heart beat Recording writer Coil Normal Box containing neart under — ore | Under Poison | Poison | | Antidote being usec as plant is about to die Pulsating leaflet Stimulated Stimulant Recording action of plant cells when poisoned and Antidote revived Poison Record of plant struggle Be... ey Plant Rapid movement Poison Record of rescue of plant Ne to left used . i— Sir Jagadis C. Bose, the Indian scientist of Calcutta n a Recent London Lecture Demonstrate I Plants, Animals and Humans Have Characteristics in C and K e Sar Way I tion, to Poisons and to Antidotes Administered to Counteract Poisons

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182 POPULAR MECHANICS THREE-SECTION LOCOMOTIVE MAKES SHARP TURNS — Three-Unit Locomotive That Can Make Sharp Turns on Railroads in South Africa; Note Position of the Driving Wheels under the Pilot Section and the Tender A three-section locomotive, designed to Ranges in a wide variety of hues, from negotiate unusually curves, has been developed sharp in Germany for the South African railways, and forty of them, part of standard gauge and part for the nar- row-gauged used in much of the African system, have been built. The en- gine is unusual in that the drivewheels under the boiler and cab, in the usual place, but instead are under the pilot and the tender. lines are not The boiler and cab are suspended between them, with a pivot at either end. The pilot with its two cylinders and six drivewheels, carries the water tank section, and the tender, also with a pair of cylinders and six driving wheels, holds the coal supply. The standard-gauge locomotive can turn a curve of less than 300-foot radius and the narrow-gauge en- gine one of about 200-foot radius. KITCHEN RANGES IN COLORS ADD CHEER TO HOME INTERIOR Color, the dominant idea in modern home decoration, has made further con- quests in one of the last rooms to be changed in this respect—the kitchen. blues and gravs to greens and They are porcelain-enamel 7 7 . lem more easily tans, are now available. coated, making t cleaned, and the substance is said not to chip, flake Heating cabinets in colors and rest of the room have also appeared to replace the unsightly black stove. or crack in finishes: to harmonize with the AUTOMATIC KNIFE SHARPENER GIVES KEEN EDGE Designed hotels, markets and restaurants, a knife recently introduced, especially for meat sharp- ener, requires no skill to operate and is said to produce a o , keen edge ina few T he done | seconds, whetting is interlac- ing blocks of car- borundum. The knife is simply forced down be- tween them and removed a few times, the sharpening being effected by the action of between EE the stones which are held close together

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POPULAR MECHANICS 183 by springs. The latter can be adjusted for ten- on and regulated to suit blades of varying thick- nesses and shapes. FIFTY THOUSAND YEARS AGO That men lived in northern Africa 50,000 years ago and were fond of oysters and clams, is the interesting evidence uncovered by Beloit col- lege scientists who have been digging in Algiers. ; Under strata of earth, J they discovered great Dining Compartment of the “Hermann Koehl,” a New Airplane in Service ; . y between Berlin and Paris mounds of the shells and below them were crude stone implements RESTAURANT IN THE CLOUDS and weapons, indicating that the users SERVES AIR PASSENGERS must have lived at least 500 centuries ago. The find is regarded as especially valuable \irplane service between Paris and B that it offers further evidence in sup lin ha been - plified by the addition of port of the belief that man probably lived ee en dining room many years in northern Africa before en- I ood 1s cooked hetore the journey a tering far into Europe. kept hot a rea tO Serve I ecial co mow Tsar scaneeroTaTORS | 5 URS Koent i Sonor of the chiel SAVES HAND LABOR iieisaiiclanaiti Farm experts in Holland have intro GRAIN REGISTER TELLS EXACT ] ’ | ' ; , duced a planter that plows a furrow and AMOUNT OF CROPS 7 4 ~ drops potatoes at regular intervals, all at OF CROPS the same time. The unit performs the \ttached to a combined harvester, an work of several men and is especially improved grain register is being used for adapted to large plantings. veighing grain. It measure ) l¢ Farm Unit That Digs a Furrow and Drops iftet ; , f 4 Potatoes, All in One Operation; Little Skill Is Required to Use the Planter Which Is ite mete | ) Well Suited for Large Farms of a ' _ to re ) | « ) c ) t l | cot t | ‘ co r é é \ | che eT | | ) e ( r | te itio +] ‘ , crop harvested

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By RALPH M. HEINTZ Builder of the ‘‘Southern Cross’? Radio Sets “@NUESS we are lost!” A For more than twenty-four hours we had been standing by at the radio-re- ceiving station in San Francisco, in con- stant communication with the “Southern Cross,” as she flew like a homing pigeon straight from Oakland airport over the 2.418 miles to Honolulu. Back and forth, over the first short-wave set to meet such a grueling test, we had chatted with Jim- mie Warner, radio operator on board the huge Fokker plane. All had gone well; all was going well, when, suddenly as a that death: “Guess we are lost!” fire alarm, came calm defiance of Helpless, knowing that gasoline was low in the tanks of the man-made bird, we realized that the lives of four men hung on that little box we had so carefully built into the cabin of the “Southern Cross.” 3ut, far out on the Pacific, an American warship picked up that call. Another heard it Honolulu, waiting for the first flash of the sun on the warrior of the sea James Warner, Radio Operator, at His Instruments in the Plane, and, Below, Reel for Lowering Aerial metal nose of the air wanderer, got it. From three scattered transmitters, posi- tions went to Warner, and in a moment came back over thousands of miles of sea:

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“O&%. GO Mie. The smallest and light- est radio set ever installed a plane on long-dis- tance flight had saved hip and lives to set a record beyond anything et attempted by daring birdmen. Avail as equatorial torms tossed the seven- ton plane like a feather on its further southward flight, shore and ship sta- Captain Charles Kingsford-Smith with One of the Wing cise Engines, and, Below, a Radio-Power Generator antil 9 tions picked up other fearless calls for po- = she sition. With the aid of the replies, re- field ceived by that tiny set, Navigator Lyon — one was able to learn that the “Southern Golde Cross” had been flying in circles, some- the

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186 POPULAR her until Warner pulled in his an- tenna about ten miles out from the suc- cessful ending of the first hop. When the “Southern Honolulu, she had with reached 2,418 miles, having been twenty-seven hours and twen- ty-seven minutes in the air. From Wheeler field, she made the trifling hop of 100 miles to Barking Sands, on the island of Kauai, whence on June 3, she took off— weighing in all 14,000 pounds—on the longest hop of the flight, 3,144 miles, to Suva, the port of the Fiji islands. On this Hawaii-Suva link—thirty-four hours and thirty-three minutes—radio listeners in San Francisco obtained contact with the “Southern Cross” the day she hopped and carried through with her until 9:00 a.m. of the next day. This transmission 5,000 miles, the which Cross”’ covered than over covered more longest distance messages ever had been sent and received from an airplane in flight. But this record was shattered when Bloem- fontein, South Africa, reported clear re- ception of Warner’s messages over a dis- tance of approximately 12,280 miles, or two and one-half times that between the plane and San Francisco. The Honolulu receiving station, Tutuila and British Sa- moan listeners, as well as warships and members of the merchant marine at sea, maintained with the “Southern clear to the moment when Warner pulled in his antenna, preparatory to land- ing at Suva. contact Cross” MECHANICS More remarkable than this, on the last hop of 1,795 miles, from Suva to Brisbane, the tiny transmitter talked to the world clearly by night and less clearly by day, though it was heard around 11:00 a. m., daylight reception, in San Francisco. This was almost 7,000 miles, a distance from which a station never had been heard in the California port. At various points on its flight, the “Southern Cross” worked with ship and shore stations on the 600- meter wavelength. Messages filed in the usual way at San Francisco, addressed to the plane, were delivered promptly and answers as promptly obtained, by relay through the steamship “Wilhelmina.” This also was the first time such a thing had been accomplished. In fact, the radio log of the “Southern Cross” is filled with first time feats of both sending and receiving Prior to the development of this set, the writer had devoted nine years to experi ments with super high-frequency transmission and reception. velopment of radio Vith the de- aviation came the insistent demand for a light transmitter with a long and the first actual with such a transmitter were made on the ill-fated Dole flight to Hawaii [t will be recalled that, after some of the planes in that flight had disappeared, the “Dallas Spirit,” with Captain Erwin as pilot, set range, experiments out over the course, searching the sea, for the missing flyers. was installed, and, One of these small sets as a result, we were in constant contact with the “Dallas Spirit” “Swinging Ship’ to Adjust the Compasses by Compensating for Errors Due to the Mass of Metal in the Plane; the Picture Gives an Idea of the Typical Fokker Thick Wing

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POPULAR MECHANICS 187

| zeaves. | 4 { OAKLAND \°%

| THURSDAY MAY 31,1928 8:52 A.M rae & HAWAIIAN DS 2 ™ a 4 LEAVES KAUAI SUVA “< ‘| PLANE DELAYED A ; DAY OW HOD OFF FLIGHT MiLes| FLYING TIME _| | th = OAKLAND 7 70 HIGH TIDES AT S. NASELAI BEACH HONOLULU | 2418 27 HRS. 27 MIN RM suva__| 3.144 | Sanies. 33m. | SYBRISBANE | 1.705 | 21HRS. 18MIN TOTALS 7,357 | 83HRS. 18MIN.

On Each of the Three Legs of the Flight to Australia the Four Flyers Winged Their Way through the Night, Two of the Hops Being Made Perilous by Terrific Tropical Storms from the time it left the Golden Gate, where the plane was. These two were until it went into a tailspin, 700 miles out, especially important just after—and to a and was lost. Before this accident, we less extent, just before—the tremendous received the dramatic “SOS” that the equatorial storms through and over which plane was falling. From this we were able the “Southern Cross” passed Follow- to locate exactly the place and time of the ing the call “Guess we are lost,” from off deplorable disaster. Hilo, for example, the plane, almost im- The two most important uses of the ra- mediately on receiving positions from ship dio in connection with the epoch-making and shore stations, was able to take a bee “Southern Cross” flight, of course, are, line for Honolulu, racing against rapidly first the ability of the small set to receive emptying gas tanks. bearings from ships and shore stations at One interesting feature was that during considerable distances; and, second, its the terrific storm encountered about two ability to send the position of the plane thirds of the way from Hawat to Suva at all times, so that shore stations and land radio reception on board the plane ships could know at any moment exactly | became impossible, because ot the

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188 POPULAR MECHANICS of the wind and the roar of the motors as they strove to keep the “Southern Cross” transmission both land constantly receiving was and on an even keel. Yet perfect at all times, and ship stations were messages describing the position and con- Thus, even though dition of the Warner could not hear sages, listeners on sea and land knew at all plane. incoming mes- times where the plane was, and any call for help could have been answered in- stantly. Incidentally, the effect of the noises was apparent when 1 motor and gale it became known that all four men were totally their landing at The transmitter with which the “South- was protected is of the short- deaf for some time after making Brisbane ern Cross” wave type, with fifty watts’ output, em- ploying the tuned-plate, tuned erid cir- cuit, and weighing, complete, eight and one-half pounds. It uses a UV-211 tube, the short-wave antenna being twenty-six Captain Kingsford-Smith with the Waterproof Radio Set and One of the ‘“Two-in-One’’ Generators Which feet long and having a special “fish” which cannot drop off, because of a peculiar spring device which takes up the stresses. One ot the most important problems of installation is that of the fish dropping off high speed, or pulling the antenna completely off the reel. The novel fish used on the “Southern Cross” cannot do [ airplane radio when going at either ot these things. The reel for the antenna also is of a special design, being so constructed that, even when freed from hand control, it automatically locks itself, and prevents the running out of more than one-half inch of the antenna at a time wave antenna is 400 feet The long- Both an- ] neo hOTIS, tennas are thin phosphor-bronze wires, which trail through a bakelite tube, thor- oughly insulated, on the fuselage. The long-wave antenna also was used for the purpose of receiving. The ( ‘ross”’ “Southern first of their type, each being incased in a duralumin generators on the } likewise were the egg,” one on each side of the tuselage. Power was supplied for the generators by small, wind-driven fans, and each egy was placed directly in the slip stream, be- ing so fastened that it could be taken in- side easily. The generators are of the dual tvpe, having two generators in one, and delivering approximately the same watt- age at 2,000 or 4,000 revolutions per min- ute. to burn out, as they In these generators there is nothing have neither com- mutators nor movable windings. fhe transmission plant consisted of three transmitters. There was a short wave transmitter operating on 33.5 meters, another on a 600-meter wave- length—the ship wave—and, lastly, an emergency transmitter, also working at Furnished the Power to Operate the Wireless throughout the Flight

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POPULAR MECHANICS 189 600 meters, but com- pletely waterproof, so that it could operate un- der water for eight hours. ] This would have enabled Warner to send messages just as long as the plane stayed afloat, either in air or on water. The receiving set also consisted of three units, | equipped with the com- mon audio amplifier. One of these was a_short- wave receiver; another a long-wave receiver, and the third, the beacon re- ceiver, On the hop from Oak- nd to Honolulu, direct messages trom the plane were received in San Francisco until very shortly before the plane 1 landed on Wheeler field. j \t the same time, Hono laa] : The Pilot’s Cockpit of the “‘Southern Cross” Is Just u ulu was getting mes- the Wing, with a Clear, but Protected View sages, starting one and one half hours aiter the “Southern Cross” the plane In brief, radio went fart] left the California port. This was alldone and accomplished more with an entirel on the short wave. new type of equipment, on the “Southern Warner also worked four ships on the Cross” flight, than it ever had done on a 600-meter wave, and communicated at will flight before. Be ee 1ore stations on the same wave- length. On the Honolulu-Suva hop, the plane was followed by Honolulu ate allan MASTER SCALE FOR RAILROADS two hours out of that port, was picked TO AID SHIPPING up by Tutuila. At night, commencing at Weighing frei; eohtis one ot the m¢ 8:00 p. m., and lasting until 6:00 a. m., portant features of railroad operatio messages were received direct from the some $4,000 000.000 are inv Ived in cl plane at San Francisco, on the short wave. annually on the United States lines alone From Suva to Brisbane, the plane was in lo insure accuracy in thi proce communication with San Francisco once, master scale has been installed in Chi for about fifteen minutes, and the re- by the bureau of standard ere mainder of the time, messages were re- be available to thirty-five railroads ope layed through ships and through the Tu- ating in the territory. It has a capac tuila land station. of 150,000 pounds, but O sensitive In other words, with a combined trans- it will register difference mitter, receiving set and = generators tenth of a pound. Expert engineet weighing only. ninety-six pounds, the required to install it and one “Southern Cross” was in constant com- interesting features of its construct munication with shore stations or ships was the anner of buildit the pit to throughout the 7,357-mile flight. For the make it strong and waterproof he floor first time in history, messages regularly is four feet thick and the le wa ive filed through commercial stations were de age two feet in thickne Spe ( livered to the plane, and replied to by ings were applied to keep out water

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190 POPULAR MECHANICS LAMPBLACK MELTS ICE TO FREE STEAMER How a learned from his school physics lesson helped a steamer captain free his craft from an ice- locked lake in Alaska, has just been told. Remem- bering that black absorbs the sun’s rays and holds the heat, the captain or- dered a long strip of refuse oil and lampblack, forty feet wide, to be swabbed across a frozen lake where his boat held. In a time, the strip had melted or that the steamer could break through the channel, Was short softened so ROTATING SHADE HELPS FOCUS LAMP Designed especially for use in hospitals, but adaptable to other pur- s, a wall lamp has a pose shade with an Coast-Defense Gun Mounted on a Railway Car Barrel Absorb the Recoil BIG GUNS ON RAILS AID DEFEAT OF “FLEET” IN WAR GAME Two battalions of railway artillery and a battery of sixteen-inch howitzers hurled that slowly in a line off Cape Henry, cently. move:l Va., re- were playing a war projectiles at four targets The gunners came, The targets represented an enemy fleet and the big guns were such as mig defense units mustered in the At the end judges declared that the artillery had won. ht be quickly event of a real engagement. ot the ‘battle.” A CORRECTION In the description of a cure for seasick- ness on page 63 of the July issue, the named in used in the cure is chemical, sodium nitrate, was material sodium nitrite. -o * a ie | error. Che the Two Cylinders above the rotating open section through vhich the rays shine out in a directed beam. To focus the light in any direction, it is only necessary to turn the shade. Somewhat the same ef- fect as is produced by a spotlight is thus and the rest of the room is shielded from the glare. obtained, Degas, ae ll i PUM ne aor et Close View of the Rotating Shade Lamp, and Drawing to Show How Rays Are Focused

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POPULAR MECHANICS 191 ROCKET CAR IS HELD DOWN TO GROUND BY WINGS lifting they exert a down- Opel rocket car, built in Germany, vard force, the new recently was tested success- fully by Fritz Opel, a former racing driver who heads the firm of builders, The car attained a speed of better than 106 miles an hour within six seconds, and reached a top speed of more than 130 miles an hour Twenty-four rockets, ments in the rear, constituted the pro- pelling force. At the that electricity. As housed in compart start, the driver closed a switch fired two rocket imultaneously by connections ignited the When the first burned down, others in turn. pair ot rockets lit, there was a tremendous roar, , ‘ they 4 ee oe ~~ » + a) ~ = . Rocket Aut in A tion View of the Mechanism and Close Photograph, Showing the Wings That Hold the C the Ground ar to ind clouds of smoke, 1 tongue ( fla ¢ r¢€ é é of the ca The flame I Ke 0 ense that spectat cr e tra were bl ¢ lo ta he ( re ] t he nventor! Max Valier i (;erman eng nee?! built a rocket airplat Ls hicl l re ported to have proved a success 1n a secret trial in the Roen mountai

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192 POPULAR MECHANICS ny ln tal A a rt: ae ae ‘wot ee a ee ete first used commercially to report on the depth of water in the reser- voirs of Washington, D. C.., answer could through Now, when it re- sponds to a telephone call, it lifts the receiver and in a well modu- lated and deferential voice says: only in code, buzzer signals. “Televox speaking.” The device can even imitate a conversation, for it is so arranged that, if some- | thing goes wrong with machinery or equipment entrusted to its care, it can lift the telephone re- | ceiver and, when the answers, say “This is operator Televox calling for” and give the proper telephone number. After the connection is. established, the conversation is carried on in buzzer | proper code. By sending the signals, the person in charge can get code replies that will fix the trouble. The talking | mechanism consists of predeter- mined conversations, graphed on a film. photo- SPOONLIKE RACING OAR TO INCREASE SPEED | As a substitute for the usual = | square-tipped oar, crews of the J University of Washington are us- How the “‘Talayha”’ Looks from the Top of the Masts; Photograph of the Slender Hull from Upper Rigging HOW BIG YACHT SPLITS WAVES SEEN FROM TALL MAST Construction that reduces the resistance of the water to a minimum is an essential factor in racing yachts, and this feature is well illustrated in the “Talayha,” one of the boats entered in the race from Los Angeles to Honolulu. \ camera view from near the top of the craft’s 120-foot mast, showed the slim, graceful lines of the beautiful racer. MECHANICAL MAN IS NOW GIVEN THE GIFT OF SPEECH The “mechanical man” invented by R. J. Wensley, of the Electric and Manufacturing company, has had the gift of speech added to his accomplish- ments. The original machine, which was Westinghouse ing an elliptical one, shaped like aspoon. Its designer asserts that it will enter the water more cleanly and quickly than the old type, enabling the oarsman to use faster strokes with greater smoothness, thus gaining increased speed. | Designed for Faster Rowing; the Spoon-Shaped Oars Introduced at the University of Washington

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POPULAR WOMEN FARM EXPERTS SPEED AGRICULTURE IN SUMATRA Women do most all of the work in the fields and in the homes among the Bataks of Sumatra. Some of their farming cus- and implements unique. lo loosen the soil for planting toms are crops, long forced This crude method has been in use for genera- poles, sharpened at one end, are into the ground and then pried out. tions and is alwavs performed by women. TWO-FILAMENT MINERS’ LAMP PREVENTS LOSS OF TIME Adequate light for the miner through- out the day is assured in a special electric lamp, developed by the General Electric Op- main has two filaments that different intensities. The one gives a fourteen-candlepower light and is used until it fails. Then a simple switch, attached to the side of the lamp, is turned, throwing the current into a low- candlepower emergency filament that will company. It erate at MECHANICS 193 Where Women Do Most of the Work; a Farming Crew in Sumatra Loosening the Soil for Seeding by Dig- ging with Long, Sharp Poles burn for thirty hours or more. This makes it unnecessary for the miner to stop worl his lamp in case of failure The light is fitted into a smal the compact, to a belt about the man’s w ist, and change | reflector o1 and is operated from miner's cap oe c beac 1 wo-cell storage battery strappe: EXTENSION RIM ON AUTO WHEEL HELPS TRAVEL IN MUD Auto eround is travel over muddy roads or soft said to be simplified with mountable « tension rim | can be quickl tached to the whee It i tened with = spe ciall designed etd se } ¥ eve Re tools are necessary to connect it and it dos not interfere with travel on pavement

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m NEW campaign in the conquest of time and space is to be launched in next few months, Germany within the when work starts on the first section of a 200-mile-an-hour monorail eventually will link Berlin with the indus- trial district of the Ruhr valley. Stream- driven by line which lined torpedo-shaped cars, air- ship propellers at either hung on ball-bearing rollers from an over- end, are to be head track. Monorail lines are not new in Germany, for several are already in operation. The novelty of the new project is the great speed expected from the use of air pellers instead of the usual geared driving pro- wheels. Electric motors are to turn the pellers, getting their energy from a trolley rail, so that no fuel will be carried. Two pro- experimental sections have been planned, Halle and the other and work on one from Berlin to from Cologne to Dusseldorf, one or the other is planned to start before the end of the year. The aerial cars have 194 TOL y»yoererx.Vovyry ay jected speed been designed by engineers of the chuette-Lanz airship company, one of Count Zep- pelin’s former rivals in dirigible building. The pro- 200 miles an hour—is prac- that of neat ly tically double passenger-carry- ing airplanes, three times the most efficient pena speed of Zeppeli airships, and almost four times as fast as the railway ifitbide for the same distance, In fact, not many racing planes, and only a very few -_ racing automobiles have ever attained it. When Ray Keech, driv- ing the W ae triplex car, powered with , recently set a new an hour three Liberty engines world’s record of 207.5526 miles on the Daytona drivers had officially mark—Capt. Malcolm Campbell and Maj. Keech made 213.90374 miles an the measured-mile course, trav- sands, only two other passed the 200-mile Segrave. hour over zaPgweserstewypwyrwyrTai#*'t.t’trwTreee

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Preliminary Sketches of Germany’s New Monorail, with Torpedo-Shaped Cars to Be Drawn by Air Propellers eling with the wind, and 201.56774 against a thirty-mile-an-hour breeze. The suspended-monorail idea has al- interested high-speed railway in- ventors because it eliminates the difficulty of building a roadbed and track capable of standing the constant punishment of fast trafic. A California inventor recently proposed an elevated monorail line for Ways San Francisco to carry cross-town traffic at sixty miles an hour or faster. His plan contemplates long and narrow cars, so narrow, in fact, that seats would be elimi- standing in a single line, would hold to a handrail to enable them to keep their feet. nated and the passengers, Moving across town at high speed, the journey would be so short, he claims, that would be superfluous. The long thin cars, seats would offer less wind resistance, and the space occupied by the support would be correspondingly reduced. Speed on the ocean and in the air is getting an equal attention. The German Dornier factory, which has share of been building double-engined flying boats with success for several years, is con- structing a transatlantic air liner in its Swiss factory. The ship, a twelve-engined monoplane, will have a wing spread of POPTTLAR 158 feet, will weigh forty fifty Following the tour tons, ans besides the crev Dornier engines will be mounted in Carry passengers, } usual design, the tandem pairs one driving a tractor propeller in front } of the wing, and its mate driving a pusher NIEFCHANICS 197

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196 POPULAR behind the wing. The propellers are to be of the relatively slow, and highly ef- ficient, four-bladed type. The passengef will contain the compartments, is modeled along the lines of a boat, even to the flaring cruiser bow, and, when at rest on fuselage, which MECHANICS Giant Transatlantic Flying Boat Proposed by a German Inventor, and, Left, the Three-Thousand-Horsepower Triple-Engined Car That Set a World’s Speed Record at Daytona Beach the sea, will be equipped with demountable boat railings. The twelve 500-horsepower engines will make it the most powerful airplane ever built. Nine men carried in the crew—two pilots, a navi gator, will be two wireless operators, two me- chanics and two stewards. Another company is experi menting with a high-speed surface liner, which, instead of being pushed through the water by a propeller, will be pulled along by suction blades, drawing water into the hull and expelling it through openings farther aft. The experimental model provides four suction turbines, two on either side just aft of the bow, and two well back toward the stern. The hull it- self would be of the “teardrop” type— the most efficient streamlined shape— fairly blunt forward and “fined down” to a point at the stern, and all the super- German

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POPULAR MECHANICS 197 structure would be streamlined to the same shape. Or Another transatlantic project proposed 2 in France is a combination of surface boat with short airplane wings and ait propellers. A small craft of this type re cently crossed the English channel in forty minutes. It combines the lifting ef fect of the airplane wings with a glider hull. so that. at full speed, it rides the surface of the sea instead of plowing through the water, thereby reducing fric tion. The wings are not large enough to ' actually lift the craft off the water. Two French engineers, Hirschauer and Talon, have invented a high-speed aerial ‘ie cableway for transportation of mails, and . are trying to interest the French govern ment init. They propose a series of tall towers, holding a sus pended tubular ~ = Twelve-Engined Flying Boat Being Built in Switzerland by the Famous Dornier Factory, and, Above, a Frenchman's Idea for a Three-Hundred-Mile-an-Hour Aerial Postal Service _maeimae~m™ rer —_—. 4 ae eon we Oe 4 Oo om

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198 POPULAR MECHANICS German Designers Have : Planned This Streamlined - ie Ocean Liner to Pull Itself - | ' through the Sea by Suck- be } ‘ ing in Water and Dis- charging It Farther Aft through Vents in the Hull Left, This Queer Craft Is Not an Airplane, But a Hydroplane, Which Has Cut the Voyage from France to England to a Matter of a Few Moments; Below, a Proposed German Air Liner to Carry 200 Passengers across the Atlantic in Half the Time of the Fastest Steamers a RRR cm

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POPULAR MECHANICS 199 EE Sie ea | cage, in which torpedo-shaped — —" mail containers, eight or ten feet long, would be driven by electric motors at 200 miles an hour. The construction, it is Claimed, is cheaper than uw derground pneumatic tube The Same Lines ; Used with Success eee | in Maj. Segrave’s Several Inventors Are Ex }—___ Racer Have Been perimenting with Changes in ¥y } Applied to the Airship Design, to Improve ® | Teardrop Motor on the Cigar-Shaped Hull + | Cars Built Abroad Used by Count Zeppelin 3 for High-Speed Since Wind-Tunnel Tests after a Operation the War Showed It Was Not LL. Altogether Perfect; One Pro- Ses a posal Is to Mount the Pro- ——— peller in the Nose and Draw 4 Pcie Air through a Tunnel in the Hull, to Avoid Gondolas on the Outside, Which Cut Down the Flying Speed | ~“s tt ro ca = - mF P * = ee Poe sin ,

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200 APPLY FERTILIZER WITH HOSE WHILE WATERING LAWN As Water Pours through the Nozzle, It Carries with It Fertilizing Material from Chamber Distributed from a container attached to the garden hose, a special conditioning material has been prepared for improving the lawn soil, preventing packing and bak- ing and loosening hard ground. Fertiliz- ing substance is applied in the same way, insuring even treatment and saving time. SELF-WRINGING MOP SOLVES CARRYING PROBLEM The problem of carrying an unsightly mop among hotel and restaurant guests to wipe up spilled liquids is solved by a new self-wringing type, for which a patent application has been filed. The mop dis- appears into a metal container when not in use, and is | ejected as needed by a lever on the handle. While it was designed primarily for use in public places, it also is suitable for homes, and the container handle enables it to be stored away with- out damage to neighboring arti- POPULAR MECHANICS cles or to the mop itself. The metal con- tainer carries a fixed and a movable roller, the latter controlled by a slide rod and handle, so they can be drawn together and held with one hand while the other operates the lever drawing the mop be- tween them for wringing. NAILS STILL MADE BY HAND IN PARTS OF ENGLAND Making nails by hand is still practiced in parts of England, where a few skilled survivors of the days when practically all the nails were manufactured in this man- ner, fill orders for units of a special pat- tern. A woman and her young niece are among the best-known workers in this field. It is estimated that there are less than fifty persons living in this part of the world who are adept at the art, while but a few years ago the craft was prac- ticed in nearly every home of every vil- lage. A few persons still retain the little “smithy” where their fathers and mothers used to work at forge and anvil. THERMAL MOTOR WINDS CLOCK AS TEMPERATURE CHANGES Since 1914, a clock in Dayton, Ohio, has been running without being wound by human hands, It is equipped with a thermal motor, consisting of a gallon tank. filled with alcohol, a one-half-inch cyl- inder and piston with a ten-inch stroke. A rise in the temperature expands the alco- hol, pushing the piston up with a series of weights weighing sixty pounds, A fall in temperature allows the weights. to de- scend, winding the springs in the clock movement. There is no escape for the alcohol or the lubricating oil, so that the clock should run indefinitely as long as there is a change of five degrees or so in the temperature every twenty-four hours.

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POPULAR MECHANICS NORTHERN LIGHTS TO ORDER WITH SEARCHLIGHT Pa Projecting Apparatus and a View of the Beams That Effectively Represented a Display of the Northern Lights; Nearly One and One-Quarter Billion Candle- power Was Employed Realistic imitations of the northern lights were produced for a conven- tion display in Florida recently, by means of a sixty-inch searchlight of nearly one and one- quarter billion candle- power, The beams were made to flicker back and forth across the sky, and the light was set on a rotating base to make the effect more natural. HOW TO TELL GENUINE HOSIERY FROM IMITATION Full-fashioned hosiery has a seam from top to toe, fashion marks under the knee and on the calf of the leg in two lines parallel to each side of the seam and ut der the instep and in the heel, a heel of distinctive boxlike structure, a diamond- point toe and an opening in the seam at the inside thickness of the garter welt. The legs and feet of such stockings are knitted separately. Imitation hose differ 4 o ' 1 ‘ | t a ——— wa i 201 in that the leg and heel are made on a ¢! cular knitting } machine the ankle bei 1aped by cutting out a I portion ot ti I material, and the instep, sole and toe a shaped by machine rhe seam re sews in. On seamless or circular-knit sto ings, there is no seam al the hot of the foot and the imitation fa hion marl do not appear at heel or instep Che te eral trade commission has warned age of the mills that they must not sell t imitation varieties as “fashioned” or “f fashioned” hosiet @ Whenever you find that vou wish know more about any article in this mag zine, write o 1 \ 1 r Bureau o | l Information. t

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Unsune of each other, every atom of air is excluded from between them stick together like a Yet, to others than who use the single bar. the men ryauges, the name Johansson is practi- 1 1 cally unknown. More than 200 pounds’ weight from a can be hung Johansson gauge blocks “wrung together to exclude the air. A pile of a dozen or more can be held out gripped by the end block, and they re- 1 horizontally, main as firm as a single ro Carl E. Johar man in the Swedish sson Was a tore- rovernment . Sweden- world’s most tamous fine-steel cities and the modern Henry Bessemer Was Laughed at by Steel Makers When He In- vented the Converter, Here Seen as It Appears in Action | HAVE more men,” said Henry Ford, in a London, than | interview in build recent “making machines to cars ive making cars Summed up in that simple announce- ment is the story of the unsung heroes of industry the ; chines that make modern nece men who build the ma sities, con veniences and luxuries possible. The man who operates the giant power press which turns flat sheets of steel into full-crowned fenders tor a fine automo- figure in a Pennell heard of the who made the press, and bile is a romantic etching, but how many have man ] therefore made the fender possible? Ford acquired one of the most remark- able, and least. known businesses in the modern world when he bought the Johans- son gauge company, and began making They turn out blocks of steel so pertectly ma- fine precision gauges in America. chined that, when several are piled on top rival of ancient Toledo and Da- U. & 1 mascus—when he conceived the idea of producing gyauge block in a variety of standard sizes so that a wide range of gauges could be 11 built up from a small number of blocks, in much the same way as a complete range of scale weights can be as few standard embled from a That was in 1897, but it was not until 1911 that Jol ansson units. ] 7 1 7 4 o was able to make the blocks in commer “ot cial quantities W 1 absolute accuracy lo day they are standard throughout the world and a machine part made in Amer- ica to Johansson gauges will correspond exactly to a similar part made in any othe country. History has had a habit of overlooking the men who stuck to their regular job and made the world’s greatest triumphs possible. learns the story of John Brown, who had a big hand in starting the Civil war, but few heard of | very Sec 100] bov ever first iB hand The unknown J. Brown was the founder of the Brown & Sharpe another Brown, whose initial also was “J,” who had a big in winning it.

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a es —— = _ ———— 4 ' (c) ¢ Kiackner The First Railway Coaches Were Modeled after the Stagecoach, Just as, in a Later Day, Designers Thought a Copy of the Buggy Was the Best Shape for an Automobile ompany, one of the world’s greatest firms the taxicab possible were _ hansson it of tool makers. his gauges and the ento 1 builder His part in the winning of the Civil of gang drills, power presses, turret lathe var was the invention of the universal and the rest of the machinery of our mod milling machine that turned out the ritle ern factories. barrels for the Union army in the govern- Even the woolen clothes of the armi | ment arsenals. It did away with the slow — originated in a machinery designer's head nd laborious rat-tail-file method and pro- One power loom can turn out as much luced better musket barrels than had cloth as could be produced by 45,000 of ever been made before. Joseph Brown _ the most expert colonial dames of W never got credit for winning a single bat- ington’s day, laboring at their hand loot le, and he never asked for it. and spinning wheels. The armies wore “The only thing that will put real pros- lots of cotton, too. A modern one-man perity into this country is machinery,” cotton gin can duplicate the effort said Henry Ford. “People believe that 28,000 southern slaves in the old day machinery brings idleness, but it is reall) \ power sewing machine, one of the n the other way about. It will produce wonderful devices in the world, can s« work. For the making of machines means together two pieces of cloth with a pet the making of more machines, conse- fect lock stitch, with nine threads feedi: quently there is more production, and and four needles going all at once, a better wages are paid.” as a man can steer the cloth over the t The World war, like the Civil war, was The armies smoked re made cigaret von by men who never saw the battle- instead of rolling their own, and could fields or smelled powder. Marshal Joffre’s afford to do so on even a soldier's pa fleet of taxicabs that turned the tide in) The reason lay in another machine that the first battle of the Marne and saved _ rolls, wraps and packs 600 cigarets a mit Paris, was the product of many motor-car ute, where the best hand labor coul t manufacturers, but the men who made do more than four in the same time

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204 POPULAR MECHANICS . wonderful automatic machine in the a fab Talk. world. It did seven operations in testing lL! cartridges—seven operations all in one machine! Some machine-tool builder de signed that, but you never heard of him tran stl m2 Bi! ‘me and when the war decorations were passed wee = || around, he didn’t get one. Nobody ever thought of decorating him. “You've heard about Watt, I guess. He gets all the credit for giving the world the steam engine. But did you ever hear about John Wilkinson? Well, the steam engine was a commercial success for just one reason—John Wilkinson’s boring ma- chine made it feasible to build a steam engine that would work. I'll tell you an other thing one of our tribe did. I'll bet you never heard of James Nasmyth. In the old paddle-wheel steamship days they put up to Nasmyth the man’s size job of deliver- Wark ita |e | | ing a paddle shaft thirty inches in diameter. He turned the trick, ; but he had to build the first steam ham- mer to do it. The ship that needed the thirty-inch shaft never got finished, And so all down line. All kinds of manufactured , | \| LOM products are cheap : ' fy to the consumer be- § 1 ie) nt iit Hi cause the manufac- turers can equip their plants with highly efficient and not too costly ma- chines. And where do the ideas for the new machines come from? Listen to a Bridgeport tool > Machines That Almost maker’s ex plana- Think Are Not Unusual; } Above Is a Sorting Ma- ion: chine for Statistical Rec- “Our customers ords, Designed by John . K. Gore, Vice President make suggestions, and Actuary of the Pru- , sae oe ¢ dential Insurance Com- and we think of nad: Oh tix Conte te o plenty more our- Gang Drill That Drills an | eikarye he oe Entire Cylinder Block in se ve Ss, In the way One Operation ot improvements on all models. For another reason, whether we like it or not, we’ve got to try to keep ahead of our rivals, if we can, in turning out machine tools which will operate with the greatest possible economy and eff- ciency and speed. In the last war, they 33 oe" m% eer as ; . - The Original Model of Blanchard’s Gunstock Lathe, 1ad a machine that was about the most First Machine to Turn Eccentric Forms from Wood

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POPULAR MECHANICS 205 because about that time the screw propeller came in and put paddles out of business. But we're still using steam hammers, “We do a lot of invent- ing. Sometimes it is a machine’ ten thousand times as powerful as any of the battering rams used at the siege of Troy. Sometimes a machine to shave a_ ten-thousandth of an inch off a piece of steel, We've got a caliper in our plant so delicate that the heat of the palm of your hand, from sev- eral inches away, will cause it to expand. We can put on a show with stunts like that which would make anyone’s eyes stick out.” Joseph Brown, of Bridgeport, was not the only New Englander who turned an inventive mind toward producing machines to make work easier. In fact, much of the early reputation of Yankees, and particularly Connecticut Yankees, was based on their aptitude for taking the drudgery out of work by mak- ing a machine do the same task in less time and in a better way than human hands could turn the trick. It was Amos Whittemore, of Massa- chusetts, who relieved thousands of New England families of their occupation of sticking wire staples, one by one, into sheets of leather to produce cards for cotton and woolen factories. Whittemore invented a machine which did the work, made a fortune by his invention, and thereby helped introduce the power era, in which the former card makers became more productive workers and the cost of cloth was correspondingly cheapened. Another Massachusetts boy, Thomas Blanchard, turned machine builder at such an early age that he was only thir- teen when he brought out an apple-paring machine that could out-pare more than a dozen girls. Blanchard, even younger, Weighing 170,000 Pounds and Exerting a Pressure of 1,100,000 Pounds, This Huge Press Makes Automobile Brake Drums from Flat Steel Disks had won local fame for his skill as a whit tler, water making marvelously complicated wheels and windmills, On _ the strength of his apple-parer triumph, hi brothers took him into business in their tack The [ those days consisted in tacks in stamping blanks factory, making of out of a thin sheet of iron, up the blanks, one by thumb and finger, and sticking them into ~ 1] then picking one, between the a vise operated by a pedal, following which a lusty hammer blow flattened the part projecting above the vise into a head. Young Blanchard’s dailv task called for a certain number of tacks, and they h to be counted to make sure ducing his full quota. His ment was a counting machine, a ratchet fit st improve and-pawl affair that moved the toothed wheel one tooth for each treadle vise was closed on a tack. time the foot Next he started work on a tack machine, and i1 six years produced one that turned out 500 tacks a minute. His patent brought

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206 POPULAR MECHANICS ¥ ~~ } iH \ \ - — a —_ “a Another Machine That Thinks Thoughts the Human Brain Could Not Compass; It Automatically Measures the Square Inches in an Irregular Cow Hide and Gives the Total him $5,000, With that money he started in st to be a manufacturing machinist, and used part of it to build a machine for turning musket barrels, an operation that was simple enough, except at the breech, where the flat and oval sides had to be ground down or chipped of. earne Blanchard produced a lathe that did the job satisfac- torily. While he was exhibiting it at the eovernment arsenal in Springfield, Mass., a musket-stock carver remarked he had one job that could never be spoiled by any machine designer. Blanchard ac- cepted the challenge, and in six months produced the first woodworking lathe for turning objects of irregular shapes. Un lathes are turning lasts, hat blocks, and a thousand der his basic patents, out gunstocks, shoe tackle blocks, ax handles, other objects of irregular form. Most of the early power machines were developed to make possible some specific product; in other words the machine was designed to fit an immediate need, and the need came first. But machine building has become such a highly developed art that now the im- provements frequently precede the de- mand from the Turret lathes, boring and milling machines, gang manufacturer. drills and power presses are constantly be ing improved with the addition of new gadgets that extend their usefulness into new lines, speed up production, increase accuracy, or simplify the work to the point where an untrained laborer can equal the product of a highly skilled mechanic of former vears. But, through it all, | the men who make the machines remain virtually unwept, un- honored and unsung, AUTOMATIC GUN FOR CALKING LEAVES ONE HAND FREE ( )perated some- what like a pistol, a gun for calking or glazing applies the material just where it is wanted and permits the operator greater freedom than with other tools, as he | needs but one . —— * hand. A large cyl- inder holds a generous supply of putty or filling substances, and ejection is ac- complished simply by pressing a trigger.

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POPULAR FORECAST WEATHER FOR WEEK BY IMPROVED SYSTEM Methods of predicting weather changes a week in advance, and with an accuracy almost as great as that for the daily fore- have been developed by C. L. \litchell, district forecaster of the weather bureau. More time and preparation are required, but he considers the results worth the extra work involved. On a casts, blank map of the northern hemisphere, he locates the high and low-pressure cen- ters of the current and the three preceding mornings, with the pressures indicated at the centers. These centers are then con- nected with lines, showing the day-to-day changes in the intensity of the areas and the variations of the low and high-pres- sure regions. With this as a basis, the lo- cations of the centers likely to affect the weather of the eastern half of the United States are predicted and entered on a chart for each day, a week in advance. On 201 days of the 276 for which fore casts were made two to seven days in ad- vance, the weather changed as predicted, giving an accuracy of more than seventy- two per cent. The record for official daily forecasts is about eighty-two per cent. PORTHOLES IN WINDSHIELD HELP IN BANDIT CHASE Cincinnati police have automobiles with bullet-proof windshields and with two MECHANICS Portholes in Windshield of Police Automobile Aid in Bandit Warfare; and the Glass Is Bullet-Proof portholes in the shield, so that persons in the cars can fire at bandits without ex- posing themselves to a return volley. The autos are capable of high speed. 207 Giving the Hedge an Even Trim with Collapsible Cutter That Saves Time ACCORDION CUTTER FOR HEDGES LEAVES SMOOTH SIDES Trimming the hedge is simplified, ac- cording to reports, with a trimmer that has nearly 100 inches of cutting edge and 1s operated like a collapsible bracket with two handles. One man ifty to 100 yards of hedge an hour with it, and there can trim less likelihood of leaving ir- regular edges. GREATER SAFETY IN SUBMARINE THROUGH IMPROVED DESIGN Had the “S-4” been ec uipped with safety | | devices developed since the vessel wa } t sunk, it would have been possible to res cue the crew, in the opinion a ho testified be fore the special senate committee invest! gating the disaster. He said that the “S-4 which was built in 1916, that period, but great developments have Spear, a naval architect w all Fats had all the safety features of since then been made creasing the chances of rescuing the crew on sunken submarines. Auxiliary an emergency controls and air locks to pet mit the entrapped among the improvements, escape of men are while boats ot the latest hull designs are better able to withstand pressure and weight.

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208 POPULAR MECHANICS the inside. The end walls of the bed chamber are of two layers of a fibrous in st - material with a dead-air space a, and ventilators covered with ling keep out insects. Where a supply is available from a pressure ss vem, the problem of keeping the flannel inoist is simple, but when water is scarce, Two Styles of the ‘“‘Submarine’’ Bed for Hot-Weather Comfort; One in the Upper Photo Shielded in Com- partment, and, Below, the Folding ~ Cover Showing the Water Pipe across the Top of the Canopy SUBMARINE BED GIVES COMFORT ON HOT NIGHTS Being unable to sleep because of the hot nights, a western engineer has inclosed his bed in a galvanized sheet-steel canopy, covered with flannel which is kept moist with water. The resulting evaporation produces a comfortable temperature on HANDLE ON STEERING WHEEL IS AID TO AUTOIST Attachable to the steering wheel of almost any make of automo- bile, a grip han- dle is said to pro- mote greater ease and safety in driv- ing. It affords added leverage and allows the operator to assume a more comfortable position. In many cases, it is said to make it unnecessary to lean for- a small electric pump is used to return the supply to a storage tank. falls on the canopy through perforations in a pipe along the roof of the compart- ment. keeps the rays of the sun from the chamber during the day. The arrangement has be- The water A wooden roof or canvas canopy come popular in California and Arizona, especially in sections below sea level. ward and does away with the use of a small pillow, which some women drivers find essential. RETOUCH MOTION-PICTURE FILM WITH LESS EYE STRAIN Retouching motion-picture film has been simplified with the aid of an apparatus de- veloped in France. Instead of looking directly at the negative, as in the ordinary process, an image of the film is projected upon a screen, along with the image of the retouching pencil, so that the worker may more easily perform the task and see small details that might otherwise be overlooked. vn

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POPULAR MECHANICS 209 RADIO REPLACES HUMAN ALARM |! mes IN WAKING PEOPLE UP : A picturesque “institution,” 1 with the long pole who shuffled a. toe streets and knocked at workers’ wv to arouse them at the proper time, 1)- idly bei 9 forced into the discard at Lan- casl ire England, by radio. Alarm clocl foretold his passing several years ago, yet many old-fashioned folk still clung to the walking arouser. But now that time nals are broadcast by radio and clocks can be adjusted several times each day, the “man with the pole” is rapidly becom RUBBER AUTO BUMPERS GUARD CAR AND PASSENGERS Interesting tests of rubber automobile bumpers were made in Germany recently. \ car was driven into the rear of a parked auto at a speed of twenty-four miles an hour, but its rubber bumper prevented damage to either vehicle, and in another demonstration, an automobile was run directly into a tree at a speed of thirty- miles an hour. According to reports, —_ neither the car nor the driver was injured Aviators with the Four-Lens Camera for Taking P! The bumpers give under strain, acting as tographs from the Air hock absorbers in case of collisions. > FOUR-LENSED AERIAL CAMERA TO SPEED MAPPING | Greater speed and accuracy in prey ing a 1 Ds are nticipate | t] i €1 camera that has four lense It wv re cently subjected to field test by flvers betore mapping an area Ot approx- imately 2.500 quare 1 eS ‘ 9 +] ‘ SUBMARINE FOR POLAR TRIPS TO AID OCEAN STUDY . ’ gas e I xpiora 1On OT polar regio} bh mea | ] . | OT subpbniat es cons1ered 1 ict Ntet ’ 1 y ¢ ] TOR telat 0 surce ead r ) | i ist recent ( er | \\ indo sed Il¢ (i¢ lle cle ‘ 1 1 +1 sub t 1¢ ul ) ¢ ( ‘ ‘ 1 Sp ‘ ¢ to \ ( 1 >) a ¢ ] | | 1 s) Ce é «x ‘ ( ' 1 | there tie ¢ é , | | ¢ at the ) e i n } Results of Crashes in Car with Rubber Bumper; Only , . . of :; ig ; Slight Damage Was Suffered the region to be Stly e ad watel

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Bert Hinkler, Who Flew a Light Plane on a Solo Trip from London to Port Darwin in Sixteen Days [\ the cold dawn of an early morning, an Australian pilot rolled back the doors of a hangar at Croydon field, just outside of London, wheeled out a tiny plane, opened up its which had been folded back to park the ship in a wings, space about the size of a family garage, and took to the air. Sixteen days later—or a trifle more than fifteen, if vou allow for the difference in time—he settled having miles, or virtually world. down to an Australian led, alone, 12,000 halfway around the In a fraction over two weeks, Bert Hinkler, a comparatively unknown test pilot, had become famous, for he had: airdrome, trave Made the longest continuous solo flight in history. Made it in a $3,000 airplane, powered: vith an engine rating but thirty horse- power, and developing eighty at its peak point. Clipped twelve days off the air record from London to the antipodes. Made the first non-stop flight from Lon- don to Rome. Crossed seas, jungles and mountains, deserts and winged through tropical monsoons day after day while keeping exactly on his predetermined schedule. At the age of thirty-six a flyer who, as a boy at Bundaberg, Australia, had saved his pennies to build gliders so that he could teach himself to fly, was holder of one of the greatest flying records ever made. The London-Australia flight was unique in several ways. To begin with, instead of ordering a_ special ship, Hinkler overhauled his old Avro “Avian” —the first of the type ever built—which had already seen hundreds of hours in the air, including a non-stop flight of 1,200 miles from London to Riga, Latvia, The original engine, never taken down, was given a “top overhaul” and pronounced ready. The original two-seater open fuselage had been con- verted, for the Riga flight, to carry only one passenger, with extra gasoline tanks in the spare seat, were needed. A small supply of food and a collection of maps were the only added equipment. Wrenches, pliers, last vear. so no changes in it screwdrivers and a gun—about the usual tool kit for an automobile journey—composed the re- pair equipment. grease wasn't even a spare tire for the landing wheels, and the tires reached Australia still filled english air. There with For cargo there was a variety of small articles, manufacturers had con- tributed to the expenses of the trip in ex- change for the advertising. Hinkler’s chances of breaking the twenty-eight-day record to Australia, set by Sir Ross and Keith Smith, in 1919, were considered so slim that the London papers refused to contribute to the expenses, though later they paid huge sums for brief cables from the pilot. Lloyds, for 150 pounds (roughly $750) had _ offered insurance’ against failure, to pay one pound if he broke the Smith brothers’ record by one day, two pounds for two days, four for three days, and so on, doubling the amount for each whose

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in Sixteen_Days Hinkler in His Avro “‘Avian,”’ and the Route Followed in His 12,000-Mile Fiight Half Around the World When He Broke the Record for the London-Australia Flight day, until they would have paid 2048 — gled with a recalcitrant hangar door be pounds if he made the trip in sixteen days, fore wheeling the ‘Avian’ out on the tar- as planned. Unable to raise the money mac. The final supply of gas was put to buy the policy, Hinkler lost the chance aboard, the last goodbys said, and at 6:45 to make the more than $10,000 which his exactly, I took off into a slight cross success would have earned. wind on the first lap of the flight to Lyons With enough money raised to buy gas or Rome, as the weather dictated. and oil, and pay his steamer fare back “The first lap was in many ways the to England, he started out. Here, in his most critical one, for, as I was fiving own words, is the story of the 12,000-mile against the sun, I had little more tl jaunt in a $3,000 air flivver, with about the — eight hours of daylight in which to covet power of a medium-priced car. some 1,100 miles On the other hand “Dawn had not yet broken when, on Europe, with its probability of bad the morning of Tuesday, Feb. 7, we strug- weather and consequent delay, presented

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212 POPULAR the greatest obstacle to a fast flight to Australia and the sooner it was left be- hind the better. “So I carried on throughout the day until, at about 5:50 p. m. local time, or 3:00 p. m., London time, the light began to fade and the rest of the flight over Italy was completed in darkness under a clear moon. There was no more welcome sight that night than the river Tiber and the lights of Rome as we landed at Centocelle aerodrome at 8:40, local time. “After a hasty meal, the machine was ‘serviced up’ and greased for the morrow, and then I turned in, pretty well beat, for, owing to the exigencies of last-min- ute arrangements, I had less than three hours’ sleep on the previous night. “At9:15 the next morning we left Rome for Malta, the British base in the Medi- terranean, 400 miles away. The route first planned had been via Athens, Cyprus, Aleppo and Bagdad, but weather and other considerations induced me to choose the alternative route via Malta, where we arrived after several hours’ uneventful MECHANICS of the seemingly endless monotony of sand, which we never seemed to escape until Karachi, India, was reached. Here, too, began the clothes-discarding process which, as we neared the equator, con- tinued steadily so that I must have left an unbroken trail of garments behind. “This first hitch in my plans came the next day, the fourth out from London, for I was unable to get clear of the desert before nightfall, and the rapidly fleeting daylight forced me to land on a patch of desert overgrown with thorns. The next day I was preparing to clear away the thorns for the fairway when a party of Arabs approached. I felt a little anxious in case they might prove to be hostile, but a timely offer of cigarets sealed our friendship, and they finally helped me clear the ground of obstructions. after, we took off and headed for Pales- tine and reached Ramleh airdrome in the afternoon, where I was able to give the engine the first real attention it had had since leaving Malta, more than 1,600 miles behind. Soon “The Persian gulf was the next objec- tive, and the 1,000-mile stretch to Basra flying. After a brief inspection of the ma- chine and engine, | was able to revel in the luxury of a hot bath. “Early the next day, the third out from England, I started crossing the sea. As with all these longish sea crossings, at first slight sense of anxiety as land disappears, but this soon vanishes. In flying over bad country, one ways one feels a is al- subcon- was the most mo- notonous of the trip, traversing the seemingly endless deserts of Syria and Arabia. After nine and a half hours of non-stop flying, I was thoroughly tired. The run next day was less tiring, and the 800-odd miles down to Jask village, on the gulf, was covered by 4 o'clock, local time. sciously looking out for possible landing places. Over the sea, vou at least have the relief that any place is as good, or as bad, as another. “We made a landfall before noon and landed at Benghazi, on the African coast, at 1 o'clock. Later in the afternoon, when it grew cooler, I flew on to Tobruck, rest- ing place for the night, and 980 miles from the morning's start at Malta. It was on this lap that I had my first experience Four Cylinders in Line Are the Novel Feature of the Avro’s Air-Cooled Engine Jask was two miles from the landing field, and the only means of transport were a donkey and a bicycle. The donkey seemed rather defective on the rudder controls, so I eventually chose the bicycle and pedaled through the blazing sunshine to the luxury of a real long sleep. “After a pleasant run down the coast, we reached Karachi, the first stop in India, and landed in the early afternoon, on the seventh day out from Croydon. I was

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POPULAR MECHANICS 213 PS vents DP eh ‘ é n With Wings Folded Back, the “Avian” Occupie« Overhauled the Engine and 14 — . ' +4 abpie to deltvet papers ontv a week old Karat and here a slight leak in the oil tanl attended to. ‘| hroughout the le thi w ' s was the only repair | had to make to machine or engine. conditions were eood on the lap, the 850 miles to Cawnpore, apart and | teal bumps encountered en route landed the after hours on military parade and tl nine lirtv-five ites of non-stop flying. “The 650 miles to Calcutta were prac tically covered in the morning, and ] ea re Dum ai Dum me and very sportingly spent the rest of landed at the Dum rport at .a friend, was at Dum to meet the dav giving me a hand. With every mile heat l read reached the st increased, and we had al ] now. the age where the tabric of the machine almost blistered one’ Calcutta onward, we entet and an East Indian rainstorm is no April sh Instead of one, the eem to the rail area ower! cool leave atmosphere pressive, ’ eC le en ( ( t eT ( é tre ( alicu : 4 r five P ' 1 } ‘ Now \] lh ma ’ + é worst ¢ ra ¢ ' oOo} | ned tive ’ ~T a i oy Tf ¢ \i co \t OH 4) ft ext o Te) md i e { \ , , cs a i a direct te a vle oht OT e ft le r¢€ t oir ' A « , ‘ l€ ( | ee } 1 é ng he i l at Iu t! ’ y ] ; ole A e ot ' 1 ea ad ) ylotted « edu ) { er ter's b t e¢ ‘) t , pt ec é ( ¢ V i is i ) ¢ 4dU e 500) r O , ced

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214 POPULAR Hinkler at Work on the Thirty-Horsepower Cirrus Engine, Which Had Already Flown Vast Distances overhead and lightning lit the darkness of the jungle “Nine fiving the brought us to Singapore. with sudden flashes. hours’ next From onward, we encountered many day Penang rains, and [ was forced to make a fifty- mile detour. As we glided down to the race course at Singapore, at 4 o'clock, 720 at Tiebad miles from the day’s start, I could see four Supermarine Southamptons, of the Far East flight [ the harbor. moored on the still waters o! Hundreds of coolies crowded the race course, and the machine narrowly | and damage in taxving in. Once again, all offers of hospitality escaped landing had to be refused, and [| retired early with my trusty alarm clock. “The take-off from Singapore was prob ably the nearest thing in a reasonably un eventful flight, for the ground was sodde1 and the managed to clear the buildings by a nar- race course none too large. I row margin, and headed away to Java. A we arrived the heavy rain- storms closed in from all sides, over island, and I was MECHANICS forced to hang around for nearly an hour before landing at Kalid- jati (near fiity miles 3:45, and Batavia) at Bandoeng east of local time. “Then, after an uneventful trip, I landed at Bima the next after- noon, and my lodging for the night was a native’s hut, and all night long mosquitoes attacked in mass formation, sleep impossible. rendering Early the next morning we set out on the final 1,000 miles that lay between us and Australia. The shortest Bathhurst from Bima to island lay over the open sea nearly all the way, but the running like a dream, and [ felt no anxiety weather prevailed all the way and the last 100 the open sea course engine was Good miles over were uneventful. “My joy when I made the land- fall at Bathhurst can be imagined. It was 5:45 when I changed the course for Fanny bay, the landing place, five miles from Port Dar win. Before I circled the Ross Smith memorial, in trib landing, ute to a great pioneer, and then landed on the crowded airdrome. I had day reached sixteenth of the journey, and, allowing for the dif Australia on the ference in local and Greenwich time, after a little more than fifteen elapsed days from the start.” GLASS TUBE IN BOTTLE CORK SERVES AS FUNNEL Pouring liquids from bottles without spilling or dripping can be done easily through a glass tube _ inserted in the cork. Glass-Tube Funnel Simplifies Pouring from Bottle

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POPULAR It serves as a funnel and is especially usetul in fill- batteries to from vetting on the floor. ing storage prevent the acid SOUND WAVES BORE HOLE IN GLASS Sound waves of a fre- 200.000 to 500,000 vibrations a sec- quency of ond, passed along a ta- pering glass rod, caused the tip to bore a hole in and a French a piece of wood Yiass, a discovered When the communi- experimenter recently. waves were cated to a glass thread about one one-hundredth of an inch thick and more than a vard long, the fric- tional effect was so in- tense that the flesh could be burned. Fur- ther tests with the “ultra-sonic’’ waves showed that they accelerated various re- actions and produced crystallization. RAZOR-BLADE “PARKING” SPACE PREVENTS CUT FINGERS Storage space for used safety razor blades is provided in a china holder that has a groove for the razor and an- other compart ment for new blades. The dis- carded units are by turning the upside down and shaking it. removed simply cabinet ARTIFICIAL SILK FROM COAL Among the by-products from coal at a German artificial silk, several tons of which were produced this plant ‘is viscose year. The amount is expected to be dou bled when new factories are completed in 1929, Benzine has also been extracted MECHANICS 215 Gasoline-Burning Locomotive for Terminal Service That Has Found Favor Because It Reduces Smoke and Noise RAIL ENGINE BURNS GASOLINE AND SPEEDS SWITCHING One of the latest devel pment in loco motives Was ex! ibited in Lo \) rele re cently in a huge gasoline-burnit unit especially adapted to vara ervice Quicker handling of trains and eat tire a , ’ witching, and less notse and moke. are important features of these « ne AUTO CLOCK ON GEAR LEVER REPLACES KNOB 1 1 . 1 In line with the tender c towat ereatel simplicity | compactness in ment, the automo- bile clock now attached to the rear-s| ft lever, serving as a sub- stitute for the usual knob \ small spring in the back absorbs the vibrations nd the hands are visible at nieht The crys al is of the un- lyr I eakable variety. —

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216 POPULAR MECHANICS soning, p¢ rts, the department of agriculture re- It stops the itching in a short time \ stain is left on the skin, but this may be removed with of acid. As the latter is a poison, it and recovery is rapid. brown a one-per-cent solution oxalic should be kept out of the reach of children and carefully used. A preventive, enabling a person to handle the plant with impunity, has been worked out by Dr. James B. Me Nair, the Field Natural History. This consists of a five-per-cent solution of ot Museum of in a half-and half mixture of water and glycerine. This should be washed freely on the skin and ferric chloride Pilot House and Body of the Glider before Launching; in This Queer Craft, Equipped with a 700-Horsepower Motor, a French Inventor Hopes to Cross the Atlantic in Sixty Hours or Less BIG MOTOR BOAT LIKE TORPEDO FOR TRANSATLANTIC TRIP and equipped with a 700-horsepower motor, a torpedo- the Seventy-five feet long craft in French experimenter hopes to cross the Atlantic. It will develop a high rate of speed and its form reduces resist- shaped “glider” is strange which a to a minimum. of and for rapid trans- ance from air and It made almost was designed especially water is entirels metal oceanic pé ystal service. CHEMICALS FOR IVY POISONING ARE EFFECTIVE Potassium permanganate, applied as a five-per-cent solution to afflicted parts with a soft cloth or a bit of cotton, has been found an effective cure for ivy poi- a permitted to dry there before going into an ivy-infested region. TI compound contains iron, which Is enters into a chemi cal combination with the ivy poison, ren- dering it harmless. SQUARE FOR CUTTING RAFTERS AIDS ROOF BUILDERS To simplify the task of rafters, a cutting special square is marked so that the proper angle to give the is desired pitch quickly and accu- rately obtained, This is accomplished with the aid of num- the square the inch rise per foot on the rafter, bers on which designate

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POPULAR MECHANICS THREE-WHEEL-BRAKE SIDECAR PROMOTES SAFER RIDING Intended especially for service in the cities where frequent stops are necessary, a three-wheel-brake motorcycle sidecar introduced. The brake to the sidecar operates in conjunction with the which controls the cycle’s rear- wheel brake. Equalization of all brakes is effected with less danger of skidding and with reduction of wear on the tires. \ regular motorcycle front wheel is em- ployed instead of the usual sidecar wheel. has been pedal CHILD’S PIANO-PLAYING GUIDE SIMPLIFIES INSTRUCTION Nursery rhymes, simple melodies and the piano are associated in a helpful guide for youngsters to enable them to play the and become familiar with rudiments of music. The unit is simply a large card, bearing an attractive picture, and the rhyme and notes to the at the top. The bottom portion is slotted to fit over the piano keys and the card is bent when in use, the upper part being upright. and the lower flat over the Below the slots are holes These are numbered to corre- spond with the figures on the notes of the little Thus the child can quickly learn to associate the note with the proper key on the piano and memorize the words, instrument some yingie kevs. for the fingers. song. Practicing with the Piano-Playing Guide 217 Single Table; Center Units and the Separate Tables in Place EXTENSION-TABLE SET SAVES SPACE IN SMALL ROOMS Assembled as Planned especially for the small apart ment, a combination table arrangement saves space and meets a wide variety of requirements. It consists of two small console tables, a card table and a wit bench. The two consoles may be assem bled as a single round table or converted into a dining table by placing the card table between them. This is made still longer by adding the bench as an e leaf. The combinations are quict Iv made NOISELESS BUILDING AGE SEEN THROUGH WELDING PROCESS Electric arc welding as a substitute riveting was used successfully in the eres tion of a large steel building P] le phia. The process is noiseless and saved about 100 tons of rivets and plates tl would have been needed by the old method,

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218 the Dual-Control Note the Two Views of Open Pit for Clear-Weather Flying RIGS PLANE FOR BLIND FLYING TO REDUCE NIGHT HAZARD 1 ——t> % Airplane; at it can be more easily and safely guided at night and at other times when no landmarks are visible, a plane equipped by M. Farman, pioneer aviator, has a dual control. A the in- stallation is that one pilot is entirely in- French feature of closed so that he must rely wholly on his turn-and-bank other indicators, and direct him. con- sidered a safer plan than the usual way, for in many compass aids to This is instances, an aviator, trusting to his senses, has become confused in fogs and in darkness, whereas, had he trusted to his instruments, he would better able to avoid mishap. have been The second pilot is in the open cockpit so he can take over the controls for clear-weather flying. OLD BEER-STORAGE CELLARS NOW PRODUCE MUSHROOMS Mushroom production has increased in some parts of the country since prohibi- tion, according toa Texas man. He points out that space formerly used for the stor- age of beer in various large refrigerating POPULAR MECHANICS plants, is now being devoted to the culti- vation of mushrooms. suited to the The areas are well as there is abundant shade and the temperature is accurately controlled by the cooling coils W ork MICROPHONE AIDS TEACHERS AS WELL AS PUPILS Sitting at her desk, a teacher in a New Orleans school can speak to the entire student body or make announcements to other their This is accomplished by the “public address” sys- teachers in rooms, tem which utilizes the microphone and amplifiers in broadcasting the through loud speakers. the auditorium enough for the 510 pupils, as all of voice The plan saved construction of an large them can hear and announcements, speeches programs in their own rooms. PLOW FOR FLAT-BOTTOM DITCH MAKES SLOPING SIDES Forming for irrigating, and other purposes, is simplified by a plow that out a ditches flat-bottomed channel with The depth and width of the ditch are determined by the position of the weight on the platform across the body of the plow. The blades that do the cut- ting are of steel and are set at SCOOps sloping sides. an angle for efficient operation. That Scooping Out Flat Bottom and Gentle Sloping Sides Ditch with the Digger Leaves a

Page 47

USCLE ana Tow to USE IT IG BILL is a trunk heaver. So is Little Bill. Big Bill is always tired. Little Bill always has a reserve measure of energy left over at the close of the working day. The explanation of the difference is simple: Little Bill uses his muscles cor- rectly. Big Bill doesn’t. Of course the average man isn’t a trunk heaver. Nevertheless, called upon occasionally to lift a trunk, run a wheelbarrow, carry out the ashes, and perform other tasks calling for physi- cal exertion. Whether the labor culmi- nates ina “broken back” or merely a natu- . The Right Way to Lift a Trunk, Putting the Strain on the Knees Instead of on the Back ral state of fatigue is largely dependent object and then straighten up. The whole upon the use of the laws of leverage. work is done with the legs; and the leg You cannot stoop and expect your arm muscles are designed for the work rhe muscles, assisted by the back, to lift heavy strongest muscles in the body are the weights. The weight at the end of the thighs. Next in order come the shoulder arms is at the end of a long lever with a It is on these two sets of muscles that the fulcrum at the hips, and the mechanical brunt of weight-lifting and hard physical disadvantage is terrific. labor should always fall, not on the ab To pick up a weight, you should squat dominal muscles and the slighter, weaker with the back kept straight, grasp the muscles in the pelvic region. Here Is the Wrong and the Right Way to Lift the } Clothes Basket; Any Weight Is Easier Lifted If } You First Bend and Then Straighten Up

Page 48

>) It Is Practically as Easy to Carry Two Twenty- Pound Bags as It Is to Carry One, Because the Man, with Approximately Equal Weights in Both Hands Is Balanced; the Chinese Coolie’s Carry- ing Pole and the Dutch Milkmaid’s Shoulder Yoke, from Which Two 3uckets Are Suspended Are Both of Them Based on This Principle The pictures at illustrate the point. POPULAR MECHANICS Zee Don’t Stand Back, But Get In \ 4 between the Handles of the Wheelbarrow, as on the Left, ‘ Bend the Knees and Lift ; Then Below, a Novel Support for the Truck-Garden Weeder correct position in lift- inga weight: the strain is improperly placed The other shows the correct procedure; the legs are bent, the weight is close in, the back 1s straight. The lift, therefore, 1s done entirely with the heavy leg muscles. rhat’s the first rule to follow in weight- Always use the leg muscles lifting: The second rule is: Get as close to the object as possible. A generation back, the “Georgia Magnet” amazed thousands of people by using this principle. Even the strongest man found it impossible to lift her body because she so cleverly contrived to keep him always at arm’s length. So, in picking up a wheelbarrow, for example, do not stand at some distance from the ends of the handles, but get your body close in so that the leg mus- cles can lift directly upward without the disadvantage of a diagonal cross strain Another important factor in weight- lifting is balance. The Chinese coolie, vho carries weights by balancing them on the end of a long pole, has the right idea. In everyday usage, the man who carries two bags of twenty pounds each has very little more to carry than the man with but one twenty-pound bag. The Moreover, when the the bottom of page 219 reason is—balance. The first shows the in- weight is balanced in this manner you are

Page 49

POPULAR far less liable to strain and posture de- fects than when the burden is carried al- most entirely by the muscles on one side of the body. Get the weight on top of your body whenever possible. It is not a good rule for wrestlers, but it saves backaches to the weight-lifter. A sack of flour, a small box, a heavy plank and other such articles should always be carried across the houlder, and not in front of the body, hanging down from the partially con- tracted arms. In lifting a _ trunk, the weight should be rested on the knees, and the heavy thigh muscles called into play. Always use the thigh muscles. It sounds simple enough, yet there are people who never give their legs a chance to prove their worth. Few people even know how to get out of a chair. The wrong way i: to put the feet far in advance of the body weight. The comparatively small-mus cled arms are compelled to do that which should properly be consigned to the heavy leg muscles. When you get out of a chair, do it with the feet almost directly under the body; it needs but a slight for- ward movement of the trunk and a gen- tle straightening of the legs to bring the body to an upright position, MECHANICS A day of Sal d expert many thing law ot lever age. For mum long-handled sh that reaso1 stretch of handled a long content your do not bend vree vou sink important contra “arm Use vour | ‘] he right a) 1 bend over ‘ he shi shoveling.” ve Carry across the Shoulder, in Front ot the Heavy Weights Not Body, and Shovel, as the Man in the Center One B iv s (one ( : , it 1S tar ¢€ ovel t 1 ou ou i arms 1n ve 1 th a rtoa ul ¢ muscle to { | © ou; ' to the t from the ] el w and Does the ??1 19

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222 POPULAR The Leg Muscles, Constantly Exercised by Walking, Are Also Made for Lifting, and Save Back Sprains All small matters. Nevertheless, they explain why Big Bill always has the back- ache, while Little Bill needs only a shower to perk him up. Little Bill knows: That his legs were made for lifting; that a weight should be carried on top of his body whenever possible; that a balanced weight is an easy weight; that the closer the weight the lighter the weight. Big Bill is always tired. Big Bill doesn't know these things. MYSTERIES OF STARS’ ORIGIN INCREASE WITH TIME Astronomers are less positive about stellar evolution now than they were twenty-five years ago, according to Prof. Edwin B. Frost, director of the Yerkes observatory of the University of Chicago, at Lake Geneva, Wis. The. nebulae from which the stars were supposed to have originated are now thought to be mere borrowers of light, shining in the illumi nation from stars near by. Another theory that has been abandoned is that the stars MECHANICS must have started from a state of rest. Observations show that they are all in motion and there is no reason to believe that they were still at any time. Better telescopes and the development of the camera have expanded the scientists’ con- ception of the size of the universe some 10,000 times, within the last thirty vears, Prof. Frost declares. Holding a dime at arm's length against the milky way,: ob scures some 15,000,000 suns, astronomers estimate, while between 300,000 and 400,000 stellar images may be revealed on a single photograph, although it covers less than one-thousandth part of the sky. A star like Antares gives the scientist some idea of the tremendous proportions of the heavens. By accurate meas- urements, astronomers have discov- ered that this body has a bulk 40,- 000,000 times that of the sun. UNSEEN SALESMAN HELPS AUTO BUYERS Persons interested in the automo- biles sold by a Paris merchant are not annoyed by the presence of a talkative salesman while examining the cars. They hear selling talk, but it is given by an attendant who sits, unob served, at a desk some distance away and describes the good points of the car through a microphone and loud speaker. he auto is stripped to show its internal parts and turns on a pivot, over a mirror, while visitors inspect it. Demonstrating Auto on Its Rack, with Mirror Below: Salesman Talks through a Loud Speaker

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POPULAR MECH ANICS

AIR-MAIL MILBAGE SIX MILLION ANNUALLY United States air-mail | planes flew 5,870,480 miles in 1927, according | ) figures just compiled | the department of commerce, and in that eriod they carried 1,- 654,165 pounds of mail nd 2,263,480 pounds of express, not to 8.679 passengers. The air iil brought the carriers an income of $2 - 643.454. The enormous iount of aerial express mention | aione hown by the figures was lue to the Ford line from Detroit to Chic car- ing automobile parts to ago,

he assembly plant in the This one line 621 pounds On May 15 there were latter citv. and ed 2.214 of express. of this vear, 11.067 miles of airwavs in daily operation, and the egular plane schedules called for the fiving of 26737 miles daily—

than the distance at the addition to Op- greate!

round the earth equator. In the regular airw 1927, avs eratiol In nine transport o few 36,918 passengers a total distance of 500,000 miles. Statistics have been com- piled covering the air-mail lines, showing that from 1918 to the end of June, 1927 the postal planes flew 15,657,530 miles, car- ried 298,517,760 letters and ninety-three per cent of scheduled ELECTRIC COOLER IN TRUCK HELPS MOTOR SHIPPING Transportation by motor truck will by t retrigeratin made more effective, it is believed, introduction of an electric unit in the carrier for shipping perishable articles. Butter, eggs and meat are no\ he ing handled by an auto-truck line in the west with the help of this equipment.

Aid of 4,000

Picture Studi 000 Candle Filming a Night wer Light

HUGE LINER AS MOVIE STUDIO AFFORDS REALISTIC SCENES 1 > In ti ge scenes fe Br on 7 tire ¢ 4 ] 4 ii ¢ C ¢ € “OT ort ] ; + ( co t r oa ) | ¢ 1 ele ( t eecdied 7 é é t 1 ed i 1 ! } em, nearly 44 OU er (one « é t ere é ( res< e t n ¢ } ( eC! g ( a epi t ( é é t n Tf he ¢ 1eéT (a ¢ é tettaundl « ner ed

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224 POPULAR end Heavy Diving Suit Designed for Work at Depths of 200 Feet and for Forty-Five-Minute Periods QUEER DIVING SUIT TO REACH GREATER DEPTHS Divers will be able to descend to a depth of 200 feet and work for forty-five min- utes and more, in a metal suit recently de- vised, its inventor hopes. It weighs 1,400 pounds, is equipped with powerful lights and its steel body has overlapping units of aluminum, somewhat like the scales of a fish. The air hose will be contained in a steel-protected sheath. MAKING GLASS EYES REVEALS BLOWERS’ HIGHEST SKILL Since 500 B. C., when they were made of earthenware and pebbles, the art of fashioning artificial has been de- Today, they are made by expert glass blowers who use no and no blowing tubes. eves veloped to a high degree. brushes than their A first step is to form a tools other MECHANICS bubble of opal glass the size of the eyeball desired. The iris is put on next by heat- ing and fusing minute streams of blue, brown and other until the exact shade is obtained. Some of the color rods have to be heated and drawn out to a fine thread. Flint soda glass is employed, as it is hard and does not irritate the eye socket. When the iris is done, the pupil is added and then the lens, a coating of crystal glass applied in a molten state. For the veins, threads of glass so small as to be almost invisible are added. The back is shaped so that the muscles will grip the eye. Cooling in a sand bath is the last step. Artificial eves have been made for birds and dogs. A Chow dog, entered in a contest, had a glass eye that was so nearly perfect it escaped the no- tice of the judges who gave the dog a mark of 100 per cent on its eyes. e@lass ICELESS COOLER KEEPS MILK AND FOODS FRESH Designed especially to prevent the bot- tle from spoiling when left on the door- step,a cooler, adapt- able also to other products, has been introduced. It con- sists chiefly ofa cone-shaped frame covered with cloth, which is kept moist by water supplied from a jar at the top. The cooler is placed over the bot- tle in a drip pan partly filled with water, to shut off outside air. The cooling is accomplished largely by evapo- ration of the water as it soaks down into the cloth. One filling of the jar is said to be sufficient for twenty-four hours or more. The cloth is easily removed for the purpose of cleaning. FIRST AID FOR GOLDFISH Artificial respiration, similar to that used in reviving human victims, was applied in saving the life of a goldfish not long ago. A woman discovered her pet lying on the

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POPULAR MECHANICS 225

loor, apparently dead. | <ap Ree SERIES ] She held it under water Ps On ith one hand, grasping with the other just back of the gills and ap- plied intermittent pres- ure. Ina few moments, e fish showed signs of fe and, at the end of

venty minutes, it was imming about in a nor- inner SAND LOADER DEVELOPED FROM TOY fovs modeled after -e machinery are ot new, but the develop- ment of a practical ma hine designed from a toy is an unusual pro cedure. A California in ventor who has produced a small tov sand loader to ld to the joys of chil- ren’s play, is preparing » market two sizes ol large machines for com- ercial use. The toy der. which scoops up = —— enti ” — ind and empties it into Powerful Airplane Beacon and Tower with Identifying Lett« the Light : Can Be Seen for More than 109 Miles 1 toy motor truck, has a ter ‘ine! disk wheel, fitted with scoop BIG AIRPLANE BEACON ON HILL suckets to dig the sand and elevate it into VISIBLE HUNDRED MILES e truck. It weighs but seven pounds,

| es in a convenient carrving case. lwo powerful beacons have been erected he large machines will have conveyor recently in California to help guide r¢ { distant delivery of the sand. planes. One is near San Francisco, tl = - S$ __— _ ——_—— other on a hill not far from Lo Angele ind eacl isible t id ‘ t i o 501 é | Ns oO | (Md CK) ¢ i | pow e P t d at the top | | MIND WORKS BEST AT NIGHT " a * STUDENT TESTS SHOW In the morning. after a nizht’s re | mind . snared ; ctivi but » re | Ce trat exp ¢ \lenta ( i re ce t ) ve ] e ¢ n t te pe \ _— ‘ 7 1 1 é ma r e r¢ ) Toy Sand Loader Which Served as Model for a Com- . ; mercial Unit; It Operates like the Larger Loaders ye COMMS

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226 POPULAR MECHANICS / LIG@WVEp ' The “Aquitania” in Drydock during Change of Rudder nected to Tackle on Ship’s Sides RUDDER AS HIGH AS A HOUSE GUIDES BIG SHIP The “Aquitania” was without a rudder for a short time recently, but no harm was done, as the vessel was in drvdock Although the rudder alone is a huge unit, it seems tiny in com- parison with the vast bulk of the ship, which is nearlv 869 feet long. dey elop 60.000 horsepower. undergoing repairs. Its engines NOISE CAUSES MILLIONS LOSS IN DECREASED EFFICIENCY According to the estimates of a British expert, noise causes a loss of more than $5,000,000 weekly in England alone. He bases his assertion on the contention that disturbing sounds of various kinds result in impaired’ efficiency § among workers of many classes, loss of sleep and sometimes illness. Many persons become accustomed to certain noises, but it is said that, although they do not appear conscious of them, the sounds have a detrimental effect upon their nerves. Tests have Pp wily : oP \4 7 3 been conducted with of- fice workers and others to show that they per form their tasks more efficiently in rooms rela- tively quiet than where there is disturbing noise. A BIRD’S EYE SECRET | Birds have exception- ally keen eyesight and the additional faculty of seeing an approaching s, | person while apparently | intent on feeding. Small birds will instantly dis- cover a hawk, although it is so high as to be merely a speck to the hu- man vision. The mystery is explained by the fact | that the bird’s eyes do ania J not co-operate but each , Which Is Seen Con- can focus on a different ; object at the same time. While one is intent on vround or other close area for food, the searching the other may be adjusted for distant vision. HAND ON REAR AUTO SIGNAL PROMOTES SAFETY So that drivers behind may clearly see what course the car ahead is to take, a rear auto signal re- cently put on the market flashes the words “Slow” or “Pass” and a small white hand, visible from a distance, points in the di- rection that the machine is to go. This is operated by a special switch, while the words are automatically illuminated, © P. & A. i.

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THEE TRETEPL ELE aiggagaaaa1 | lied Drawing of the Chicago Daily News Building, Show- ing the Smoke Chamber over the Railroad Tracks, and the Stacks to the Top of the Chamber B* covering buildings, cities are their railroad tracks with utilizing valuahle congestion and to hide htly terminals. The first notable de velopment of the “air rights” in Chicago is now under way with the construction of a twenty pace to relieve unsig five-story skyscraper, the he Chicago Daily News Interesting engineering problems were solved in this project. new home ot t In the first place, 100 caissons were sunk 100 feet to bed rock to support the main structure, and fifty- nine were dug to hardpan as foundation GRAVITY STACK FOR SMOKE DISPOSAL r Rights Skyscraper= Swallows. re mecttn CERES a! Cer etre for the feature of the buil prising nusual and beautitul \ll ot them, com more than two and one-half miles plaza, an wu ot boring, were made with: ing train service, although they are scat tered among the network ot track th

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228 POPULAR MECHANICS

HOIST FOR ELEVATING DIRT

WEE), > < sa meee dearese a eee =f % ——— SS tage 6 2 . i rm ‘ structure is its vast chamber and exhaust to lead off smoke from the trains. A ceiling is to cover the entire track area and in it will be specially de- signed slots, over the center lines of the tracks, with openings greater than the width of the locomotive stacks. These lead into the smoke chamber, varying in height from two to ten feet, from which the fumes are led up through the Trains Were Not Interrupted while the Building Was Erected above Them; Note the Caisson in the Inset, Close to the Track stacks to the top of the building. In the was done by erecting scaffolds and plat- main stack, containing 220 square feet of forms for the dirt-bucket elevators, so area and extending 335 feet above the that trains could run underneath. tracks. the smoke is conducted by gravity. The second unusual feature of the Domes, or extra-high places in the smoke

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POPULAR MECHANICS 229

SPECIAL DOCK FOR a} dill < a ee __ oe

i ATT ae, a eet "1 ~ — f rT Bi SPECIAL BRIDGE OVER TRACKS REMOVING CAISSON DIRT

ite ; eae | Ty sce . : . ; " Li A : mY CROSS SECTION DIAGRAM [::,Q)=2-" OF TYPICAL CAISSON |:

Rapid Dirt Removal Was Made Possible by Erecting a Special Dock and Dumping the Debris into River Barges chamber, provide large volumes of space for receiving smoke and leading it up through the main stack. In case the gravity exhaust for either the principal or the smaller stack is not sufficient, motor-driven fans are to be in- stalled on the roof. When the railroad is electrified at later date, the space devoted to the smoke stack will be converted into office room. The Daily News will occupy the first seven floors of the building, except that shop space will be rented on the inn Hee - street fronts and the main concourse. The remaining sixteen regular floors will be leased to outside tenants. PPPS yi Two smaller additional stories on top of the building will QUICK house rest rooms as well as the offices and studios of a radio station,

30 FEET- The building was designed by Holabird & Roche and } is being built by John Griffiths & Sons. It is of the modern “stepped-back” design, Indiana limestone being / the principal outside material. The ground floor is 212 / feet wide and nearly 400 feet long. The plaza, approxi / mately 150 by 250 feet, will be just across the river from MNT f ) Ist ac \ BEDROCK / the $15,000,000 home of the Chicago Civic Opera com- \ BED K J pany, which is also under construction at the present = = : time Real-estate authorities estimate that in Chicago there is property valued at more than $409,000,000 which might be developed by utiliz ing the air rights over the tracks, as has been done in the Daily News buildi:

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230 POPULAR | > ' It Does the Work of Several Clerks, the Coin-in-the- Slot Stamp Dispenser, in New York Post Office COIN-IN-SLOT STAMP DISPENSER ; FOR POST OFFICE Distributing stamps from a coin-in-the- slot machine is not a new idea, but the method has been amplified in a dispenser installed in the New York post office. It delivers several denominations of stamps besides books of them, stamped envelopes and postal cards. No extra charge is made for the service, the customer get- ting the full equivalent for his money just as he would at the regular stamp window. FEVER FROM LOW-WAVE RADIO TO HELP TREAT DISEASE That radio mav be used indirectly in treating disease, is the possibility sug- gested by recent investigations into the effect of waves of low frequency upon the human system. It had been noticed that men working about a six-meter set in an eastern laboratory frequently fainted, or became ill. A fever was present in al most all cases of this kind, and experi- ments showed that it was induced by the action of the waves. In treating some diseases, fever is induced to kill germs that will not live at high temperatures, so it is thought that radio waves may be used for this purpose. MECHANICS PROBING THE TOMB OF FIRST ARTIST OF ALL HISTORY The tomb of Imhotep, the first great Egyptian architect and the first artist in recorded history, is believed to have been located by excavators who are probing the tamous “Step Pyramid” of Saqqara, known as the oldest stone building in the world. The pyramid was built about 3000 B. C. by Imhotep for Zoser, famous pharaoh of the Third Dynasty. The exca- vations have already disclosed that the name Step Pyramid, given it because it rises in a series of terraces, is a misnomer, for the original pyramid was smoothly faced with limestone blocks, but later pharaohs had their workmen steal the ready-cut blocks to face their own pyra- mids, leaving the denuded base. The ex- cavators have uncovered a series of prin- cesses tombs, with delicately fluted col- umns, long series of underground passages and rooms, many lined with blue tile, and believe they have located the entrance to the burial chamber of the architect. They found a robbers’ shaft, where tomb looters had reached some of the chambers seventy feet underground, but the discovery of a limestone stairway, leading down through a long sloping cut in soft rock, indicates the robbers never reached the real burial chambers far underground. ELECTRIC PRESS FOR NECKTIES HELPS PRESERVE FABRIC Neckties are kept in good condition at all times with the aid of a small electric presser which is suitable for home use. (he tie is moistened slightly and then 1 ylaced between +71 the two sides of the unit, which ap- ply pressure and eat from 1 light ing socket. A inetal tongue, in- serted in the tie, keeps the seam and lining from showing through on the face and helps hold the fabric for pressing.

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POPULAR MECHANICS WORLD’S OLDEST STONE BUILDING YIELDS SECRET 231

LIMESTONE FACADE ~« ORIGINAL SMOOTH LIMESTONE SURFACE ‘ ‘ “STEP PYRAMID Ge. 200 FT. HIGH oN =

TEMENOS WALL SQUARE 68 FT. THICK 33 HIG INCASED IN LIME STONE

.

CENTRAL “SAPARTMENTS SLINED WITH GeeSlUEsriles. ; ae } <a Lies Th NT | TL

at. SUNKEN MASONRY INDICATE L SHAFT BELO GREAT CUT ™ 7 IN SOFT ROCK 7 FOR EXCAVATION / OF TOMB —* WOODEN. BEAMS IN FAIR PRESERVATION FUNERARY" @ WERE. CHAMBER LOWERED ) Ps i. - LA /) if, THREE GREAT IM PASSABLE PLOCKS, ; ‘ ey LIMESTONE ad j i LIMESTONE STAIRWAY « , ] BEAMS-~ FOUND NEARLY FULL OF SQUARED _ ~ BLOCKS a | PALLEN ROCK |

ALTAR 50 FEET FROM ROCK AND) INCASED IN LIMESTONE —+— m - at ae } ) Bidoien DOORS yf ) DEBRIS y CLEARED

t CUT |

fi | fi

N, SUPPOSED FB & 7 * ’ URTHER PASSAGES : FOUND HERE A : ALABASTER F JARS FOUND ROOMS LINED WITH BLUE TILES

| os. W. Cl The “Step Pyramid,”” Above, with Lines Showing How It Appeared When the Original Sn Lime Facing Was in Place, and, Below. Diagrams of Some of the Underground Chambers Which M Le i Burial Chamber Far Older than King Tut-ankh-Amen’s

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For Service in Rough Country; an Thren-Whedled Motorcycle Tested by Military Experts in England THREE-WHEELED MOTORCYCLE TRAVELS ROUGH GROUND Designed for cross-country service, a three-wheeled motorcycle has been tested in England. There are two small wheels in the rear and the machine has a duplex steering arrangement. The cycle has been proposed especially for military uses. BIG GLASS TESTED AT NIGHT TO REVEAL DEFECTS Light, and plenty of it, is usually re- quired in searching for visible flaws in any object, but the seventy-inch disk of optical glass recently made at the bureau of standards for the Perkins observatory at Ohio Wesleyan University, was sub- jected to its most exacting tests in dark- The reason was that the internal condition of the big piece of glass is re- vealed by passing beams of light through it and then studying the patterns and ness. POPULAR MECHANICS colors that result. This can be done sat- isfactorily only in a dark place. There was no room large enough at the bureau, so the tests were performed at night. At least 100 feet of unobstructed vision was necessary in making the proper observa- tions. The examination revealed that the distribution of internal strain in the piece was remarkably uniform, and that the de- gree of strain, per unit of thickness, was less than is frequently found in small lenses and prisms used in optical instru- ments of the highest precision. The glass is eleven inches thick and weighs 3,500 pounds. It was baked for eight months under graduated temperatures in a spe- cially constructed furnace. Four previous attempts to obtain a disk of this size had been unsuccessful. PICTURES “PAINTED” WITH SAND INSIDE OF BOTTLES Forming pictures and designs of col- ored sands on the interiors of bottles, is the interesting art hobby of a California man who got the idea from a natural group of “painted rocks.” The grains are careiully arranged with special instru- ments to achieve the effect and the bot- tles are packed full and sealed so that the sand will not become loose and spoil the pattern. Fifty-six shades, all of natu- ral colors and of samples sent to the artist from different parts of the world, are em- ployed in making the designs. Completing a Sand Design on the Interior of a Glass Bottle; the Grains Are of Many Different Colors

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POPULAR MECHANICS 233 CRUCIBLE STEEL IS MADE WITHOUT FURNACE Steel is made by elec- tric current, without the use of wires or a furnace, under a process recently developed. The material | is melted inside a wooden | box that remains quite cool to the touch. The method is adapted to the melting of crucible tool steel, which has been made in clay pots heated in a furnace and lifted out with long tongs. Under the new process, some 450 pounds of metal are put in a sin- gle crucible surrounded by an inch of sand to pre- vent the radiation of heat. Around the sand, is a coil, cooled by water, carrying a _ high-fre- quency alternating elec- tric current. The whole is encompassed in a wooden casing so that L.._.._.{........................ ae the apparatus resembles Making Crucible Tool Steel in a Wooden Box, Which Contains the Crucible a large packing box. By One Sae Cena Clean Seem action of the current in the coil, although in the metal until it is melted and, at the there is no direct connection with the same time, the steel is made to move vio- crucible: or its contents, heat is induced lently so that a thorough mixing result GRIP GUIDE FOR GOLF PLAYERS third and fourth fingers of the player’ HELPS IMPROVE GAME seorcicniggyy weeds aubergine re aeacoeste traps. Once adjusted, there is no need Easily slipped on, a grip arrangement is to loosen the strap. It is slippe said to teach the beginner hqw to hold his | off like a glove Left-handed 1 ve tne thumbs and_ fin- . it on the right hand, on the third and gers in the proper | ourth finge It ( manner, to strengthen the left hand and in- FABRIC FOR CEMENT ROAD SIMPLIFIES REPAIRS sure control of the stroke, especially at the top of the i fabric of loo ‘otton mes! trord swing. It auto- cleavage between the foundation and the holds _“———- uetase material Wheo the ton | matically Sul ce \ ¢ the club in the fingers and lifts the palm must be repaired, it can be ret ed, and away from contact with the shaft at the a new surtace installed thout impair- same time. The guide is worn on the’ ing the more permanent base below it.

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The “Train Shed” Take Off an of the New Airport to Be Built at Pau, France; 1 Land within the Giant Airdrome, International Planes from All Europe Will Safe from Rain and Snow French Plan Airport Modeled on Railroad-Terminal Lines, with Giant “Train Shed” for Air Passengers A RADICALLY new idea in airports is “= to be realized { Pau, If c miles from Bordeaux, as a result of com firtt _ aeey airdrome Maur ice who also has won a traveling scholarship petition tor ft e pest plans. The winner of tl Chauchon, permit him = to architecture, has taken the railroad-terminal idea and applied it shed” of heroic dimensions, the passengers of the leur an international air lines will em- bar] ind debark, sheltered from the eather and protected from the dust or mud of the ust landing field. The enor mous landing room is to be 370 feet wide and OH) deep fut hi vy ple t ot room to1 ree of the largest air liners at one e lhe coming planes, landing on theo field ix! directly into the helter, and after unloading, will run out aga d down the line to one of the rov of hangat oO le of i Two viant searchlights will be mounted at the front corne of the land ng shed, one of each pair pointing d rectly upward it night as | icon lights, and the other led across the field, to furnish a stream landing planes rhe field, leve sous . Oot tiumination for throwing marking beacon of the three vertical beams. will be at one side of the h eround, will be covered with heavy gla and electrically lis elit ed by In addition to the iniaiilaie angars, and the name, set in the ) night. room and 1 | hangars for the planes, the pian mncius machine shops, storehouses for spare parts, a restaurant, hotel rooms, custom office, information bureau, ticket ind even a booth where money can be ex for the currencies of any other isited. o the traveler will 7 changed J J tion supplied with funds of the right kind. Although the designer only twenty-eight years old, has won a number of prize contests since his graduation the famous Ecole des Beaux-Art The American Institut of Architects established the skeet scholai hip, which has M. Chau valuable contribution to inte education recognition of our aoe been awarded chon, as “a and i national architectural eracetul education il debt to France.”

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POPULAR MECHANICS 235 Designer’s Sketch of the New Airdrome, Showing Planes Preparing to Taxi Out to Take Off with Passengers Night View, Showing Beacon Lights over the Landing Shed, Horizontal Flares, the Illuminated Airport Name and the Row of Hangars An Aerial View by Day Will Appear from an Approact senger Liner: Note the Br ————— ——

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236 POPULAR Steadying the Small Motion-Picture Camera with the Shoulder Strap and Supporting Rod STRAP HOLDS MOVIE CAMERA FOR STEADY PICTURES To keep the small motion-picture cam- era steady while in operation, a shoulder strap and supporting rod have been intro- duced. The rod is placed in a socket at the lower part of the strap loop, which is easily adjusted to fit the wearer. The ar- rangement makes it easy to focus the in- strument, takes the weight from the hands and arms and eliminates most of the both- ersome shaking in the finished reel. AUTO CLOCK LIKE SPEEDOMETER WITHSTANDS SHOCKS Resembling a speedometer, a clock for the auto- mobile instrument board is said to keep accurate time in spite of the jolts and jars it re- ceives, and has the further advantage of being more easily read than the usual dial. No hands are exposed, merely the nu- merals, the hours being displayed in an upper opening, while the minutes are reg- istered in a window below. co * MECHANICS THINKING MACHINE FOR STORE HELPS RECORD SALES Constant record of merchandise, from the time it is unpacked until it is sold, is kept by means of an apparatus devised especially for department stores. It com- bines the functions of tabulating units, telephone selector devices and electrical transmitters and recorders. A chief pur- pose is to enable clerks and others in va- rious parts of the store to transmit a quick and accurate record to the central office, where the data are conveniently ar- ranged for auditing or other examination. Transmitters are distributed in the va- rious departments of the store and con- nected with the recording units at the cen- tral office. By inserting a punched card into the transmitter, a record is made at the main desk of such factors as the sell- ing price of the article, the salesman, cashier and the customer. The installa- tion is said to save time, reduce trouble by eliminating the loss of bills and mer- chandise slips, and to afford a means for a quick check-up. MINNOW NET COMES APART FOR EASY PACKING For greater con- venience in carry- ing, a minnow dropnet is quickly taken apart when not in use. The hoops are made of steel and the net is shaped to insure a large catch. The outfit is light in weight and rolls up into a very compact bundle. “ROBOT” TO GIVE ANAESTHETIC SAVES EXTRA ATTENDANT A mechanical unit that administers anesthetic has been developed by a Uni- versity of Maryland professor. It does the work of an extra attendant and is also said to prevent an under or overdose, as it uses the exact amount to keep the patient unconscious. Its operation is gov- erned partly by the subject’s breathing.

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POPULAR MECHANICS POWER OF AUTOMOBILES EXCEEDS ALL OTHERS If all the automobiles in the United States were linked to the stationary engines of all descrip- tions and sizes, locomotives and windmills, the motor cars would outpull the entire assembly, ac- cording to figures compiled by the department of the interior. In 1923, the horsepower of all gen- erating equipment, exclusive of pleasure automobiles, was 230,- 514,000, while the total, including pleasure cars, was 684,044,000. In 1849, two-thirds of the total in- dustrial power equipment was found on farms, but in 1926, the farms had only seventeen per cent. Between 1899 and 1923, the capacity of this equipment in- creased 260 per cent. If con- verted man-power, this amount of horsepower would furnish sixty servants for every person in the United States. into CYCLE LEAP THROUGH HOOPS FEATURES MOTOR CIRCUS At a recent motorcycle show in London, a rider demonstrated his skill by driving his machine through a double paper hoop while going at high speed. The stunt re- quired a steady hand at the take-off, since the obstruction was of considerable length, and there was danger of turning the front wheel so as to make landing hazardous. a - a ho w NI Foam Apparatus, and Draw- ing to Show Application to Oil Fire FOAM GENERATOR STOPS FIRES IN OIL STORAGE TANKS Adapted to the protection of oil storage tanks of moderate size; a foam generating unit has introduced. It operates automatically, mixing a special fire-smoth- ering powder with flowing water and dis- charging it to the top of the tank, been EGGS TESTED WITH EYEBALLS TO INSURE HATCHING Hatching eggs in incubators is popu larly supposed to be a modern method but it has been practiced for many years in Egypt The incubator is a dome shaped building of mud and brick with six com partments, each having capacity of about 500 Heat furnished eggs. Through the Double Paper Drum; a Motorcycle Thriller from smoldering barley and wheat straw which i spread in troughs. To determine if the eggs are being kept warm enough, the attendants hold them against their eveballs. It d that a high per- centage of chicks are hatched in this way.

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23% POPULAR MECHANICS Going to Sea in a Basket: HUNT MYSTERIOUS . Passengers Boarding the ‘6 99 “Llandovery” during a DEATH TREE

i aomte @ tes oe IN AFRICA ompanion Ladder Explorers have rone into central Africa to search for a strange plant which natives call the “death tree.” According to legends, anyone who rests in its shade becomes unconscious and, if not rescued in time, dies. Na- tive criminals are some times put to death by be

ing bound and placed un- der the branches of the tree, according to reports, Pending the findings of the expedition, scientists are reserving opinions concerning the tree. ’ Years ago, the upas tree of Java had a reputation even worse than that of the death tree. It was

said to be fatal to anyone who came within ten or PASSENGERS PUT IN BASKET welve miles of it. These stories appar- TO BOARD STEAMER ently grew out of the fact that the natives were in the habit of dipping their arrows High seas prevented the use of the com- in the poison sap of the tree. panion ladder when passengers wished to board the liner “Llandovery” at Port | BAG HAS ELECTRIC HEATER TO KEEP WATER HOT 1 lizabeth, South Africa, recently, so a large basket was lowered from a derrick

and the travelers swung to the deck with Usefulness of the XY out difficulty. The container was fash- hot-water bag 1s in- KES ca , ssindeiaiaiieaacs NY } ; ; ; II KA ioned like an elevator car. creased by inserting a a \ WN ° ° . 4 < 4 \4 special electric heating a ¥ unit into the neck to CLASPS FOR AUTO SKID CHAINS \ 2 keep the water warm. A SIMPLIFY ADJUSTMENT It is supplied with cur- ey lor easy attachment of skid chains to rent from a lighting the automobile tires, a special clasp ha socket and is not in- been introduced. tended to heat cold water, but merely to The links of the keep the contents at a high temperature side chains are The attachment may be screwed into any slipped into hooks standard hot-water bottle, is safe and con- on the clamp, the sumes but little electricity. car is driven or rolled forward, @Those wishing further information on pulling the chain anything: described in the editorial pages

with it, and, after can obtain it by addressing Bureau ot one revolution, the links are in position Information, Popular Mechanics Maga- for connecting and the clasp is removed. zine, Chicago. g!

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POPULAR MECHANICS 239 MOVIE STARS PLAN HOME BUILT IN SIDE OF CLIFF A five-story house, clinging to » Am the solid rock at Solano Beach, Calif., has been planned as a home by Douglas Fairbanks and Mary Pickford. An elevator shaft, ris- ng partly within the rock wall of the cliff, will serve the various floors, and drop to the sea level. A driveway on the top of the cliff vill reach the garage, built on the ame level. Above the garage, will be the library, while adjoining the car space, will be the kitchen. A living room and an open piazza will occupy the next floor below, followed, in turn, by bedrooms and, on the lower floor, the dining room and another open veranda. Both the elevator and open stairs, and an ornamental iron rail, will lead so 3 BEDROOM not ‘eta down to the next level, at the > | 1 Tenenar water’s edge. The plans call for an adaptation of California Spanish ELEVATOR |1% if : IN! Sle SiDE OF CLIFF architecture, SHAFT Artist’s Sketches of the Seaside Home Planned by Douglas Fairbanks and Mary Pickford; at High Tide, Boats Will Be Able to Land at the Base of the Cliff, Mooring at a Swimming Float, While trom the Top- most Floor a Wide View over the Pacific Will Be Available g!

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240 POPULAR layer Posing with the Mechanical Stroke Instructor; It Helps Teach Correct Form for Various Shots

DUMMY AS GOLF INSTRUCTOR SHOWS PROPER FORM Golf swings are executed in correct form by a mechanical model which shows the proper position of the arms and legs at every point of the stroke. It is ad- justable for drives or putts, and enacts every portion of a real stroke even to the follow through. PHOTOGRAPHS MADE ON STEEL WITH HIGH EXPLOSIVE Shooting a photograph into hard chrome steel with a high explosive was accom- plished recently at the bureau of mines, A camera print was laid on a piece of the steel, about two inches in diameter and an inch thick. <A disk of nitrogelatin was placed on top and fired. The paper photo- graph was completely destroyed but when the steel had cooled, a profile of the sub- ject was found impressed on the surface. Where the picture had been black, that is, in the shadows, the surface of the steel was raised, and where there had been high lights, the steel was cut out. Another ex- ample of the effect of explosives in mak- ing pictures of this kind was obtained by transferring words impressed into the sur- ME? HANICS f the block of explosive upon a disk el. The action is explained by the li hat, when the explosion occurs, the entire amount of the solid is converted into gas which momentarily has the same shape and size as the original block of explosive. Where there is a cavity in the explosive material, the rapidly moving gas molecules find the line of least resist- ance for escape and in so doing, they col- lide with each other, producing a vast number of tiny “drills” which bore into the hardest steel. A somewhat. similar result was effected in blowing open a safe with a hollow cylinder of dynamite. <A number of sticks were tied into a bundle, the center ones pushed out with a tin can and the rest fired in a vertical position. After the explosion, there was a hole in the safe corresponding to the hollow cen- ter in the ring of dynamite stick. VIOLIN WITH STRAIGHT SIDES IS EASIER TO PLAY Instead of being curved, the body of a violin constructed by a Chicago maker is angular, the form enabling the player to reach farther on the strings although his fingers may be short, and making the in- strument easier to hold under the chin. At the same time, an improvement in tone is claimed for this pattern, less likelihood

Inventor with Violin of Angular Pattern, Which Is Said to Be Easy to Play of breakage and greater simplicity in man- ufacture with correspondingly less cost. _———— sree i

— eed el

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i POPUTI > STREET PAVEMENTS OF DIAMONDS IN KIMBERLEY Blue clay, containing diamonds, was used in paving streets at Kimber ley. When the mistake was discovered, the ma- terial was scraped up and carefully washed housands of dollars worth of the gems were found, including several large ones, Huge blocks of jasper, topaz and jade were ground up to make roads in Swerdlovsk, Rus- sia, and at Woolwich, England, waste from an arsenal was used for a road. It was found to contain brass valued at nearly $200 aton. Inthe Wl MECHANICS 241 East Indies, roads were sometimes made of cam- phor wood, a rare and costly variety which is now valued for interior panelings and other fine finishes. In the city of Lyons, France, a costly road about one-eighth of a mile long was finished by laying the top with blocks of glass. MILLION PIECES WASHED DAILY IN SLEEPING-CAR LAUNDRY To maintain its “household on wheels,” the Pullman company washes 1,000,000 pieces of linen daily for its 9,000 sleeping cars. It has sixty-six laundries in different parts of the country, so that fresh equip- ment may be more easily gathered and the soiled linen collected. A stock of 10,- 000,000 sheets, pil- 3aby Giraffe in “Skyscraper” Crate for Shipment; the Animals Are Difficult to Keep in Captivity in Northern Climates “SKYSCRAPER” CAGE IS NEEDED TO SHIP BABY GIRAFFE Caring for giraffes in captivity is one of the most difficult tasks of t he anim a , 1 e eeper as the specimens are delicate and subiect to manv ailments in northern cl: mates. Shipping them is also a problem In transporting a baby giraffe, from South Africa to England, recently, a “sky scrapel * crate | ad to be constructed OBSERVATORY IN ARMORED CAR HELPS GUARD MONEY Guards riding with money in an armored car used in a western citv, can command - ] a wide view ot low cases, towels and sundries is Street, and to the re maintained and 100 through an obser seamstresses are atory in the ro employed to do the | | The gla | mending. Some 400 . windshield an persons are required he idl or] ts ire to keep constant | e bullet rot V check of the bed riety ind ic linen About 2,- ito ' 000,000 pieces dis- [| __ aac a S ” ' appearannually and Observation Cage on Armored Car Gives Treasure panei 9 790,000 wear out, Guards a Wide View Ahead iro

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q } 1)

Modern Protection; Here, Engines Are Pumping Water through the Lines to the Top of the Tower on the New City Hall in Los Angeles 242 Skyscrapers Are Relatively Fireproof, but Powerful High-Pr | IS a touch my = Ca ind William F oll iwoi men, one of them lugging wm Fa huge camera. hurry from an of ce oft the Detroit fire head uarters, leap into a car and speed » a burning store, blocks awav. lé@ Call, telephone, 1 received by metroma battalion chiet at the e \\ , Smith laze. Sergeant Georg MecDonne the a pior eer oi ki d, are on the trail of a fire swindler loan unpracticed eve, there ttle to indicate < Iwthing unusual n the moldering debr of the tore’s interior. But a trace of ite dust attracts the investi itors” attention. “Celluloid!” they exclaim, turn- ng to the battalion chiet “You were right. This 1 a touch off, ure.

essure Systems Are Installed for Added

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[| suspected something is wrong. No wonder ree fires popped up at once,” says the chief. The lust, sprinkled along the floor, had fed the hungry lames like gunpowder. Sergeant Smith, who takes and develops all tures himself, setS up hi camera and snaps a half dozen views of the interior of the store. McDonnell crapes up a bit of the powder. It will be sent to the city chemist for anal ysis. The merchant’s pa- pers, ledgers and other documents are seized. Fire- men are closely questioned. Was the store locked when they arrived? Who has the keys? Where is the proprietor ? Was the stock piled around the fire? Any- thing else unusual? A fight to expose the fire Sergeant George W. Smith of Detroit’s Arson Squad, Examining a Fire-Ma : “4 pie ing Machine; This One Failed to Work and the Swindler Was Caught swindler—one of the clev- erest, most dangerous and most destruc- incendiary fires was $755,112.35 he tive of all criminals —1S on, Since Nov average for t! e next five veal Wa le 1, 1921, Detroit’s two-man squad has beet than $265,000 annually During the first engaged exclusively in this kind of work. ten months of 1921, there was not a single hey started when the city was suffering conviction on an arson charge In No a veritable epidemic of “touch-offs.” Fires vember and December of that vear, the were being set by contract. Chief of De- squa 1 effected three, and, since that time tectives EF tward H. Fox and Fire Marshal have obtained thirty-two more. Detroit C. S. Goldwater finally decided to “fight insurance rates were lowered in 1923 fire with fire.” sulting in a saving of more than $300.00 “Trained fire swindlers?” thev said: to the citize1 The arso1 ruad, in tl ‘all right. we ]] meet them with men spe opinion ot t] e it urance companie cially trained to discover their tricks.” one of the reaso1 tor the decrease \ccordingly, the arson squad, one of the “If you can’t send a man to jail for first in the country, was established undet arson, vou can beat him in another he supervision of the police department iid Sergeant Smit! “You can take the and composed of an experienced detective proht out o} nre I t cant pe ] I al a hreman, both empowered to make tressed too stro1 o}) \1 1 low 1 t] irrests and to seize evidence, if needed, the swindler. He is bound to lose in without formalities of warrants In the the end I don’t know of a vear the squad started, Detroit's loss from in this city in which the swindler ha

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POPULAR St ae ee profited. Since the squad was organized, actually more than $300,000 in in- have been surrendered by the assured. We are able to convince them that their surance policies chances of vw} Wi collecting, 1en the fire is of a sus are slight. 1 iasses picious origin, “There are fourc of incendiary fires: Those set to defraud the insur- ance companies; those for revenge; to cover up another crime, and those ae eee In the first three classes, especially, there is often started by ‘bugs.’ great difficulty in establishing a case. The motive is not always clear and the evidence is frequently burned up. “The fire bug, that is, the pvromaniac, is not as clever as the swindler, but he is a greater menace. You don’t know or where he will break out. found that he just after a big fire, with which he may have had nothing to do. when But we have will often become active The excitement seems to inspire him to some fire starting of his During a costly blaze here. wn own, ] four recently, a pyromaniac dashed into office ditferent ] and set eight the and ht in buildings fire He was caug act con- Intended to MECHANICS hun- dreds of fires throughout fessed to setting the country, among them aze. At the helped take a hospital bl time, he had the patients out and place 4 Start a Blaze, but It Failed and the Arson Squad Caught the Maker Then he set the institution for them in a hotel lobbv. hotel on fire. He's in an the criminally insane now, but the tragedy was that he could not have been caught sooner. Fire fiends often start their ca- reers with the relatively innocent amuse ment of turning in false alarms for the fun of seeing the engines. But anvone addicted to this malicious tendency should be curbed at once, for he is a potential pyromaniac. When the excitement of see- ing the engines has died down, he is likely to trv starting fires for an additional thrill. not with He is usually so clumsy “Our main trouble, however, is the pyromaniac. that he leaves clues, and once captured,

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POPULAR MECHANICS 245 pitiful mental condition is not difficult for a competent physician to determine, In the case of the swindler, we are deal- ing with a criminal who has no thought for the danger to which he may be expos- ng others, and who usually is also smart ough to realize that, if possible, he must ver up his tracks. The swindlers are rrowing more and more clever in their ; technique, but here is something they often overlook. The very pains they take to start a ‘natural’ fire, to stage a ‘perfect crime, in other words, may be their un- loing Take a look at this!” He shoved a queer-looking wooden contraption icross the desk. “That's a fire machine and it’s a dandy. But, fortunately, it didn’t work. Notice | that a razor blade is attached to the alarm clock in such - a wav that, at a cet orate re lad tain time, it will vi- ire ude \ é brate and sever the / c coils and b string, and the | omeien ‘ he aid . “41 | ] 1 weight will pull a es and othe strip of abrasive itu along the place Sometime ui right here, where ee to be against some matches were thre ller Not inserted. But, in oO, a man this instance, the O en gallo , aes , , matches were a oO test gaso fraction of an inch é er re too high. The ab i l touched i m ‘ le ca f}\ n ) + ) eT) P ne | g aimo oO r ) \ i. * ’ } i¢ i Ct ) ) t \no e1 ys Te yb ‘ ‘ ] ‘ ] ‘ pa ingee¢ 1 ) ¢ thot he d pie 1] eft ) el ett oO t] c ) re ) Ca I Cc ¢ He ad ¢ T i ( is ¢ ) 3 i so cou | t | ive t h cat | e tire He eve ) i telieg im ¢ ict ( T { as 1 | re ) ! é ¢ ¢ ] ) t , rie t } | V¢ id] ¢ ¢ } But he lett é ore | c¢ © ¢ subsequentls howed The point Sergeant Smith and William F. McDonnell Answering clinched. when the chambermaid te t Call; Chemist Analyzing Fire Evidence and McDon- that she ha found | e yndisturhed nell Inspecting Kerosene Container

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246 POPULAR Alarm Clocks Are Favorite Tools of the Fire Swindler as Well as the Bomber, but Their Use Is Discouraged When Alert Arson Squads Are on Duty when she went to the room next morn- ing Had he mussed up the covers, he might have made his alibi hold. Some- times, but rarely, the swindler’s conscience him. Sixty -five best of walked gets the Not long ago, a miles to Toledo . strolled into the police station there and gave himself up. It happened didn't that this fire was of incendiary origin, but we found that the confessor had told the truth.” man after starting a fire here that we know In many cases, careful examination of the books, a thorough inventory and com- parison with bills of the wholesalers who sold the dealer his merchandise, will re- veal the discrepancy in the storekeeper's statements and show the motive for the fire. Weeks and quired in preparing a case for court. squad often re- rhe unturned in its months are leaves no stone evidence against a swindler. ‘ Che records are consulted to determine if search for the person under arrest has been in sim- lar trouble before. In the office of the fice detectives is a complete filing system containing the disposition of court cases the squad has handled, data on arrests, how fires were started, and other informa- tion useful in checking up on suspects MECHANICS Often a fire swindler will be caught in a net that he least expects—his fingerprints. Convinced that the fire would destroy his trail, he mav be care- less about handling glass bottles of inflammable liquids he uses in start- ing the fire, with the re- sult that his finger marks are plainly visible. In ex- amining a suspicious fire, the arson squad makes evi- If the prints are found, they are photographed careful search for dence of this kind. and with the police records in an effort to trace the suspect. checked as usual More careful examina- tion of insurance appli- cants, inspection of prem- ises and repeated check- up of stocks by insurance or other authorized bodies, would help check arson. Sergeant Smith declared. GLASS HOOD ON AUTOMOBILE PERMITS VIEW OF MOTOR So that spectators might easily see all exterior parts of the motor, a demonstra- tion car was constructed with a glass hood. This permitted running the engine with- and assisted the demon- strators in explaining various points. out exposure wel Demonstration Auto with Glass Hood over the Motor, So Engine Can Be Seen in Operation

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POPULAR MECHANICS 247 MOTOR FUEL FROM SISAL PLANT SUBSTITUTE FOR GASOLINE Approximately eighty gallons of motor fuel can be produced from an acre of sisal plant by a chemical process developed in i The and other fibers, ordinarily wasted, are utilized and, under certain conditions, the by- product can be used as fuel without fur- ther treatment. Sisal is cultivated on a large scale in northern and western Africa for rope and matting fiber. At a recent exhibition in France motor fuels derived from nuts, corn France, it is reported. leaves and bananas were used to run machines, but these products are believed to have too high a value as foods to justify their conversion into gasoline substitutes. The sisal, on the other hand, offer a relatively cheap and abundant supply of material for fuel. is said to SHEARS AND NIBBLER IN ONE SAVE USE OF DRILL As a substitute for the usual drill in preparing templates and gauges of metal, a combination of shears and punch has been introduced. It is portable and is said to cut smoothly, requiring little fil- ing, time, and can be quickly attached to Saves any vise. Powertul leverage is af forded, and it is designed for accu parts are fitted with New little difficulty. work. rate RECLAIMED U. S. LAND YIELDS BIG CROPS Land considered practically valueless a few years ago, but later reclaimed by ir- rigation and other projects, has yielded more than $1,000,000,000 in crops in the last ten according to government reports. Last the value of from this acreage was more than $133,- 000,000, the highest since the peak of 1919. Alfalfa led all other products from the standpoint of years, vear, crops acreage, being grown on thirty-one per cent of the total cropped area of 1,431,560 acres. Electric Signal Lan- tern Made More Ef- fective by “Stop” Warning on Red-Cel- luloid Disk ELECTRIC HAND STOP SIGNAL TO PROTECT PEDESTRIANS Asa substitute for the ordinary tern, a red lan introduced an electric stop signal for night use at dan- western inventor has gerous crossings. It is supplied with cut rent from a battery and, when the bulbs flash on, they shine behind a red-celluloid disk or which is the word “Stop.” SPOON ON METAL BOTTLE CAP AIDS IN TAKING MEDICINE Designed especially for those who have to take liquid medicit put on the market with a spoon at- tached to its metal cap. When not in use, the spoon fits closely to the side of the and also helps to identify the bottle container so that it can be picked from a cab inet with less like lihood of a mistake

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248 POPULAR MECHANICS TWO-WHEELED FORTS AID POLICE WAR ON BANDITS

* ea | S > | Bullet-proof shi mounted on two- wheeled trucks for quick maneuvers, are | being tested They \ the London police. are high enough to protect the entire bod, and can be set at different angles. FISH ANSWER CALL TO DINNER AQUARIUM TESTS SHOW Interesting that fish sometimes learn to associate signals kinds with food, made by an English research worker. <A common species of shore fish that likes to ike its home in a jar when kept in an experiments showing of various have been aquarium, was taught to respond when the temperature of the water was raised slightly into the At first, a worm was dropped tank as the heat upon seeing it, the was applied, and To Demonstrate the Portable “Forts’’; Squad of Police- men Advancing on Party Pos- ing as Bandits 1,000, not enough for the human palate to detect, caused the fish to search for its food after it had learned to associate the change with the bait. Others replied to a tuning fork, to a buzzer and to electric lights. One was taught to enter a food bottle when a light was switched on and wait for the worm, MODERN “SEVEN-LEAGUE BOOTS” AFFORD HIGH SPEED Ordinary walking speeds are accelerated several times, it is claimed, with a pair of spring cog-wheel shoes which were exhibited at a re

fish left its jar to devour the bait. Later on it acted similarly whenever the temperature was raised. Another learned to respond to’slight alterations in the salinity of the

show in Lon- They are somewhat like roller cent don. skates with a special driving mechanism, which is said to be easy for the wearer and makes it possi- ble to attain a rate

water. A change of but three parts to Cog-Wheel-Drive Roller Skates on Which Person Can Develop Speed of Thirty Miles an Hour as high as_ thirty miles an hour.

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POPULAR MECHANICS 249 MAN’S ANTIQUITY VIDENCED BY NEW FINDS Additional proof that men lived upon the earth hundreds of thousands f ago, has been found in a number of chipped-stone arrow and pear heads imbedded in he banks of the Nile ver. The discovery was made by an expedition under the direction of Dr. James H. Breasted, of the University of Chi- who regards it as an important geological testimony that the men who made the _ spears must have lived at a time corresponding to that of the Ice Age in Europe. An additional find of in- that of the ot years cavo, terest was & . ‘a iifarhieews oy skeletons of thirty-one Hittite men and women in a mound of clay formed by the disintegration of the brick homes in which the people lived. The structures are believed to have been built at least 3,300 vears ago. From the skele- tons, scientists hope to establish the bodily appearance of the Hittites and so con- tribute to our scant knowledge of them. JEWELS ON LICENSE BOLTS INCREASE MOTOR SAFETY Colored reflec- tors of red and green glass on the license-plate fas- teners have been introduced to im- prove the car’s ap- pearance and also to promote safety. The jewels serve as supplementary lights, the red be- ing used behind, and the green for the front plate. metal parts of the fasteners with a rust-resisting metal. The are plated Tri-Motored Sweeping Outfit Removing Mud from the Bottom of the River Avon in New Zealand; Silt Is Stirred Up and Carried Away MOTOR-DRIVEN RIVER SWEEPER SIMPLIFIES MUD REMOVAL Mud and debris are quickly removed from the bottom of the river Avon, at Christchurch, New Zealand, with the aid of a three-motored sweeping apparatus. The unit is not a dredge but operates more like the sluicing outfits used in gold mines. Water is pumped up through large pipes and discharged again while a current of air is introduced at the serves to agitate the mud and silt into suspension, so that it can be carried off downstream. nozzles. his water, driving the CROSSING RADISH AND CABBAGE LATEST PLANT TRIUMPH What is regarded as an achievement in plant breeding has just been accomplished in the production of a cross between a cabbage and a radish. The two are of remote relationship, hence the hybrid considered far more remarkable than those vielded by crossing varieties that more close] resembl eac other

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250 POPULAR Policeman Using Portable Radio Loud-Speaker Set for Giving Orders; the Pole Is Collapsible PORTABLE LOUD-SPEAKER SET LATEST AID TO FOREMEN For bosses of street gangs, police and others who must address crowds, a port- able loud-speaker apparatus has been in- troduced in Germany. It consists simply and a The is quickly assembled and is con- of a horn, batteries, microphone sectional pole to support the horn. outtit structed for long service SEA OVER SEVEN MILES DEEP ECHO MEASURES SHOW Depths of between seven and eight miles have been found in the ocean by means of the recently developed echo-sounding ap- paratus. ‘This system of measuring the depth of the water is considered a great former method of ead which could rarely be used five miles. By revised and more improvement over the sinking a 1 for a depth greater than ; the echo measurements, accurate charts of the ocean’s floor are indicate that the “can- vons and valleys” at the bottom of the depth the height of the loftiest mountain ranges on land. being made. Phe. Sea exceed in MECHANICS THREE HUNDRED AIR SCHOOLS SHOW AVIATION’S GROWTH According to reports of the department of commerce, more than $6,000,000 is in vested in air companies engaged in reg ular flying operations and there are now over 300 schools of aviation in this coun try. Planes and engines valued at nearly $24,500,000 were produced in 1926 and 1927, and last year companies engaged in regular transportation by air flew 5,809,999 miles on scheduled trips and carried 8,500 passengers, 2,261,507 pounds of express and 1,654,454 pounds of mail. LONG STEEL SPAN IN BRIDGE REPLACES STONE ARCHES Five Roman arches in the famous high bridge over the Harlem river in New York are being replaced by steel, 426 feet The reconstruction was necessary as the water, swirling about a single span of long. the stone piers, had made them unsafe, particularly bridge carries the water of the Croton aqueduct. Al- though the expense involved is large and the work . demands skill, the bridge less than because the great engineering will cost some $500,000 would have been required by the alternative of driving a tunnel under the river to carry the water. “y Old High Bridge over the Harlem River and the New Structure, Below, Showing Span under Construction

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POPULAR MECHANICS y= Js — BRITAIN’S BID FOR THE WORLD’S AIR CAPITAL THE ARRIVAL AND DEPARTURE. § PLATFORMS OF THE NEW AIR STATION We E NT ENTRANCE HALL t DEPARTURE |NDICATORESMETEOR@LO GICAL CHARTS, BEC: : — , . c) The Illustrated Lor n News At Croydon Field, the London Airport, England Has the Finest Air Terminal Yet Constructed. | Since the Recent Opening of the New Buildings; a Feature of the Waiting Roon Is the Clock Board That Show Arrivals and Departures over All Europe

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252 POPULAR MECHANICS THE TRAINMASTERS OF THE AIR WHO USE RADIO

f , } 4 j | JAIN, CONTROL ROOM WITH MAGNETIC] MAP ON WHICH P ARE PLACED ARROWS DENOTING THE|DIRECTION OFTHE _ WIND, AND SMALL METAL INDICATORS REPRESENT IME ‘T POSITION OF MACH ELECTRIC | MASTER CLOCK CONTROLS ALL OTHER) CLOCKS

NAVIGATION OFFICE TO CORRESPOND TO AIRPLANE AS RE PORT ee AIRPLANE INDICATOR ee — MAGNETIC MAP WITH AIRPLA <jcmaNDt Rs “IMPERIAL G-EBLF CARLING NNT 8 oP Rows: 3 | G-EBLF cating. passing 8a THEN KNOWS MACHINE 1S : THE CHANNEL AND [5S PASSING INTO ZONE WHICH IS UNDER THE JURISDICTION oe CH, CONTROLLED FROM ARDROME. PARIS. ce |

& U RR ; - * OPERATORIIN iN aut ME MUNICA ne a Si nl VIGATION IN BFLIGHT on r2 ©) pric e e x48 a . - ° - A ROYDO ° L) - ~ ° e J OO} = Cie

The Illustrated The Control Tower atop the Croydon Terminal Is a Busy Place When Planes of Five Nations Are Arriving and Leaving; Magnetic Maps, Wireless Weather Reports and a Complete Weather Observatory Help the Aerial Trainmaster Keep the Traffic Moving

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POPULAR MECHANICS 253 AND WEATHER CHARTS TO DIRECT TRAFFIC MOVES THE NEW CONTROL TOWER AT CROYDON LS t cH AIR en WAND INDICATOR eet Re. COMMUNICATIONS #¥ : FROM AIRCRAFT LAMP IN FLIGHT FOR — eee DIRECTIONAL . Saece ae oF. eae + WIRELESS ~~ ae = ovat teal %, Die. ae ~ o% Be ~ “i OLD AIRDROME BU ESSE SS) CONTROL ROOM WITH WIRELESS he ee PLATFORM ee a at —_ Si SNAL (eee =“ CHART = —CUSTOMS t ait OFFICES; @ "ec b ale rf a ree xn pes FRENCH —— — 07 — wth — —- — A — — GERMAN —— Seine ONLY JIN THIS WAY DETAILS OF FREVGHT AND The Cross Section of the Control Tower Shows the Operating Side of the Big Airdrome from Which a Net of Air Lanes Spreads over Europe; a Horn, Called a ‘“‘Hooter’’ in Engl and, Signals ‘the Nationality of Planes Sighted on the Far Horizon

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254 POPULAR End View of the Swinging Park Seat, Showing the Coin-Slot Compartment and Locking Mechanism COIN-IN-SLOT SWINGING SEAT LATEST PARK CONVENIENCE Patrons of parks, amusement resorts, and other places may enjoy a reserved swinging bench as a result of a California inventor's product which has just been in troduced. Dropping a nickel in a slot of the locking mechanism at the side tips the seat up for use and the bench automaticalls returns toa tilted position when the occu- pant leaves it, so that the next person also must insert a coin. KETTLE GIVES WHISTLE SIGNAL WHEN FOOD IS COOKED Suited especially to boiling eggs or cook- ing vegetables, a kettle now on the market has a small steam whistle in the cover. This sounds YOUR EGGS ARE COOKED z when the contents have been cooked to the proper de- cree, thus insuring more satisfactory reduc- ing the amount of dishes and Fuel is also with or with electricity, as it may be reduced or turned off when the whistle blows. waste saved, especially when cooking gas MECHANICS SAFETY RAZORS’ THICK BLADES LAST INDEFINITELY A safety razor using full hollow-ground thick blades, the same as an old-style im- plement, has been marketed by an English firm of Unlike other safety types, the blades of the new razor are not discarded, but are rehoned after each shave and used indefinitely. The razor and sword makers. original safety razor was a guard on an old-style blade, but did not prove satisfac tory because the honing problem was still left. Then came the clear thin blade, which could be discarded. With the de velopment of satisfactory automatic strop pers, the new-type blade was made possi- ble. It looks like a short usual thick blade. section of the FRUIT SQUEEZER FITS ON TABLE AND SAVES TIME Quickly clamped to a bench or table, a hand-crank fruit squeezer juice from large , or small removes the oranges, grapefruit, lemons and other fruits without the hands. crank ridged shaped soiling The turns a cone- member like that of the small glass ex- tractors and, by pressing on the ' — fruit with the other hand, practically all of the juice is quickly removed. The squeezer is easily cleaned and durable. AIR-RAIL PASSENGER ROUTES TO SPEED TRAFFIC Regular journeys from coast to coast in forty-eight to fifty-two hours, are planned by joint airplane and railroad transporta- tion. Passengers would use the trains at night and the planes by day. A traveler going from New York to St. Louis. for instance, would start at six o'clock in the evening by rail and transfer to an airplane at Columbus, Ohio, the next morning, ar- riving at his destination hours ahead of the train schedule.

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POPULAR MECHANICS 255 yr HIGHEST TIDES ON == ———Y ATLANTIC COAST Used in the Hand or as a Head Lamp on According to the latest Car, Magnet Light Is are . Effective records, the highest tides occur along the At- nt tic coast, where the range is from one to fifty feet. The highest are found in the Bay of | Fundy. In New York | harbor the range is about four and one-half feet, while at Eastport, Me, only a few hundred miles distant, the tides have a range of twenty feet. Boston’s tide rises ten feet, while at Key West, Fla., the ocean’s tidal va- riation is but one and one-half feet. Helpful in Trouble, as It Can Be Placed on Any Metal Part MOVING PICTURES EXHIBITED ON AIRPLANES Motion pictures were shown to passengers on an airplane trip in Cali- fornia recently, the inno- vation proving so popu- lar that the company has decided to include the feature as a regular part = ; of all long journeys. The screen was AUTO LIGHT WITH MAGNET BASE stretched at the forward part of the cabin. FITS ANYWHERE ON CAR A five-reel comedy was displaved. Look- ing at the pictures is said to offer relief Both hands are left free tor work and for those who are affected by flying. the trouble of adjusting a clamp aved f tl in ¢ C er ‘ | strong, magnet base It is magnetizec Pet yy, cul eC! t ( n { - 1 i BRONZE GRILLE ON HOUSE DOOR GUARDS AGAINST BURGLARS io P ( ( re ( ( | i Loo! 1 ( t ( é rronze ( th n oO can he ened ] r , ; , , neh ie without opel ¢ t ‘ ? ( Mod erille 1 Ol the outet cle 1 the . —s = ——————————— — — 77 , ‘ screet tT qdaitiol 11 tect | é l Airplane Passengers Enjoying Motion-Picture Film; eee er a - «i } | ' the Show Helps Prevent Air Sickness

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256 POPULAR Parachute Jumper Wearing the Fabric Fin Which Helps Prevent Spinning in Descents FIN FOR PARACHUTE JUMPERS AIDS SAFER DESCENT So that the jumper may more easily guide himself while falling through the air and also avoid twisting and turning immediately after stepping from the plane, a fin arrangement has been devised for the parachute man. It is simply a web of fabric, pulled on over the legs and func- tions somewhat like a fish’s fin or rudder, to keep the wearer more steady in the air. Its chief aid comes before the parachute has opened, as, after that, most of the steering and guiding is done by pulling on the ropes of the canopy. CROWN WASHER TO HIDE NUTS IMPROVES LOOKS OF WORK Quickly set over nuts or screws, a crown washer gives a better ap- pearance to the surface and pro- tects the unit be- neath. It can be painted over, giv- MECHANICS ing the appearance of rivets, or may be plated to add a touch of brightness: As a protector, it prevents tampering with screws and nuts. COAL SMOKE CAUSES COLDS CHEMIST SUGGESTS Gases from the smoke of soft coal may be partly responsible for colds, in the opinion of Prof. Samuel W. Parr, of the University of Illinois. He suggests that the effect upon the nose and throat tis sues of the billions of cubic feet of sulphur dioxide and other vapors that pour from the nation’s chimneys each year be inves tigated. Approximately ninety per cent of the fuels burned in this country pro duce smoke, it is said, and the amount of soft coal consumed totals over 600,000,000 tons annually. AUTO DRIVER’S POSTURE PAD PROMOTES HEALTH Greater comiort and avoidance of trou- bles resulting from improper posture are claimed fora spe- -—— - cial cushion de- vised for the auto mobile driver. It is shaped to give support to the back where it most necessary, is molded and padded and is quickly adjusted. GLACIERS TELL THEIR SECRETS IN CLOCKWORK “DIARY” Glaciers move spasmodically and not in a uniform manner, like a stream of oil, as has been held by some scientists, evidence gathered by Prof. R. T. Chamberlin, of the University of Chicago, shows. For seventeen years, he has been studying ice fields in Canada, Alaska and Switzerland and has obtained the glaciers’ own story of their movements by means of a clock- work mechanism which scratches telltale lines on a disk as the ice moves. These “diaries” indicate that there is a sudden slippage when the ice yields to an accu- mulated stress.

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POPULAR MECHANICS 2! ULTRAVIOLET RAYS (ag REVEAL TOOTH CAVITIES By directing ultraviolet rays upon the teeth, dark pots, where small cavi- ties are beginning to de- velop, have been revealed in tests conducted at Northwestern University dental school, The teeth react to the ravs by shin- ing brightly with a vis- ible light, but if a cavity is forming, that spot does not glow under the rays even though no coloring matter has yet appeared. Further investigations of this method of examining the teeth are expected to lead to the development of ultraviolet lamps with which a competent dentist may make a thorough inspection and remedy cavities before they have done harm. UMBRELLA-TOP GAS STATION HAS AUTOMATIC GONG To shelter himself from the rain while operating a gasoline pump, a_ western service-station man constructed a metal top over it in the form of an umbrella. He also rigged a gong signal, so that, when cars drove up, it would ring, telling him that a customer wanted service. Gasoline Filling Pump with Umbrella Canopy, and alae — vietanaate . — Which the Car Sounds Bell Signal for Service rug, olten permanently spots it. 77 N Rowing Class Watching Their Strokes and the Coach in the Big Mirror Teed * os ROWING PRACTICE WITH MIRROR HELPS TRAIN OARSMEN So that they may more easily correct their mistakes and learn to stroke to gether, boys training for the crew of an eastern preparatory school, practice in front of a large mirror. This enables them to see the effeet of the coach’s di rections and gives each man a clear view of the entire crew. LIFE OF RUGS IS FIFTEEN YEARS, EXPERTS SAY Dropping cigar ashes on rugs or car- pets will not damage the fabrics, experts a declare, but mav have a_ bene- ] ficial effect instead, for the ash is displeasing to moths. With proper care, a rug or carpet of good quality should last at least fifteen years, it is said. In sweep- ing, the strokes should be with the nap and not against it. Un 1 even floors and travel over the rugs may cause them to change shade in spots. This difficulty 1 can be remedied by turning them frequently and lining them. In using a vacuum cleaner, the tachments should be properly ad- justed to prevent damaging the rugs, and using a beater is often harmful as it breaks the strand Face powder, dropped upon the Treadle by

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By EARL CHAPIN MAY 5 waeeaiebras most of them live in daily 44 danger of nasty falls and other acci- dents and are listed as extra-hazardous risks by life-insurance companies, circus riders are quite as particular about their horses as about themselves, especially their “principal” and “finish” horses. A principal horse is one on which the beautiful lady rides around the magic ring. Such a preferably, one with a broad back and a large barreled body and thin legs. horse is, It should be gray or white be- cause a principal horse is a “rosin-back,” that is, its back is covered with powdered rosin to keep the rider from falling off. If the horse is gray or white the powdered 258 pa =e vs It takes at least two years to make such horses ready for the ring and riders do not have the oppor- tunities to train or break them they had. When an expert rider finds an untrained horse that looks good to him, that horse may be worth in a livery barn or on a farm $100 or may be less. rosin doesn’t show. sut if its color and lines meet the rider’s requirements, he tests it, first, for ticklishness. He digs his fingers into what, with human beings, would be the lower ribs on either side of the spine—the small of the back, as we would say. If the horse flinches or wrin- kles up its skin, it means that it is ticklish and will not do, because the rider’s feet “take off” and land on that particular spot. The horse destined for circus life must be broad-backed because a rider not only has to stand on it, but must pirouette, or whirl, and even turn somersaults and must have a broad landing place. For a similar reason the horse’s rump must not slope too abruptly toward the tail, or the rider, in “landing too far back,” might not be able to keep his feet. After a “green” horse is selected, the animal is given its first lesson out of doors. It is saddled and bridled and ridden a few

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||ORSES minutes daily for many weeks. Gradually its mouth is curbed, that is, its chin is pulled toward its chest if it is to be a principal horse, because curbing makes it canter best. But care is taken in curbing it, for some- times a horse too tightly curbed will rear back- ward and break its neck. Once thoroughly accus tomed to close curbing and to the saddle girth and to the human weight broad back, the s given a on its equine pupil lesson under the roof of a big ring barn, but it is still saddled and bridled like any horse. During this second stage of breaking in, the animal is gaited, with the reins and bit, until it canters or lopes around the ring both ways. In a act the principal riding mount rider move from right to left. That is the way you see them the band be But during the second stage of train and when ~~ gins to play. ing the green horse, who is either gray or white, is also sent around in the ring in the opposite direction. This is to cure it of shying. Any normal horse soon gets used to the ordinary sights and sounds of circusdom, even to the presence of the ele- phants. After that, it only unusual or shies at the something it cannot readily see. In loping around the ring from right to left, its right eye takes in everything outside the ring, the only place any unusual sight or sound can come from. which is about But the left eye only gets an occa- + Diy de. ~ “4 Daring Riding and Spectacu- lar Feats by Matched Groups of High-School Horses Fur nish Many Circus Thrills in j These Motorized Days ional elin » of what mav be happening sional glimpse Of what may € appening in the world outside the ring. And such a glimpse some horses may shy. S the well-trained ring horse is taught to see the outside world with both which it back to the regular 1 to-left loping inside the curb. eves, afte goes Circus riders try their best to prevent because, if a horse shie ider is standing on its back, the rider is certain to fall heavily. E all shying, partly when the 1 ven 1f the to the equestrian 1s nearer ground, a sl] ] - | 1 ing horse can do a deal of harm. Some

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200 POPULAR MECHANICS time ago May Wirth was doing a fancy stunt in which, with one foot caught in the girth or “roller” of her horse on the ring-curb side, she leaned inward across the loping horse and picked up a handker- chief from the ground, While she was do- ing this stunt at Brooklyn during a mat- inee, a strange dog came yelping down the hippodrome track, the horse shied at this unusual sight and sound, threw May clear across its back and left her hanging outward, head down, with one foot still caught, while it ran around and around the ring, dragging the equestrienne’s face May Wirth, Most Famous of the Women Riders, with Her Snow- White Horse, and a Difficult Bal- ancing Feat, in Which Baskets Rob Soft-Soled Shoes of Their Gripping Power in the cinders and banging her head against stakes and curb, until spectators stopped the frightened ani- mal. It was two weeks before May could This training advances from the second ride again. stage to a third, during which the saddle is

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POPULAR MECHANICS 261 taken off, a roller, or broad leather girth with two handholds on the up- per side, is buckled closely around the horse’s belly, and a lunge rope is napped into the bridle bit. The trainer holds he other end of this rope he stands in the center of the ring and with a las] whip urges the animal to canter or lope close to the curb. The whip is used sparingly, because much whipping ruins the spirit of any horse. As soonas the horse knows that the whip can sting, it is no longer necessary, except as scenery. For quite a while the rider practices vaulting, aided by the handholds, from the ground to a sitting position on the horse. In time the rider assumes an up right position, then gradually works into pirouettes and somersaults. Usually, after the horse has learned to stick close t@ the ring curb and to lean inward to oppose the centrifugal force and to keep on go ing steadily, the lunge rope is discarded and the animal is permitted to go and stop 7 2} ae ¢ PaasMe . . 0 x only at the spoken word. _ toe ~~ o Re, = C ar a mm ul irnour, I ircus Jidest wn

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262 POPULAR MECHANICS Until recently no principal act was com- plete without obstacles and Some of the obstacles were hurdles—poles extending from the ring curb toward the center of the ring. The horse was taught to hurdle, usually while still working with saddle and bri- dle, just as any hurdle horse jumps in steeplechases. Hav- ing learned what hurdling meant, the principal circus horse hurdled automatically. Another kind of obstacle was the banner, or long and wide strip of colored cloth, under which the animal loped and over which the rider leaped. Six of these were held by banner holders, who stood on the ring curb. Half the suc- cess of the trick was in the manner of holding, by the banner men. They had to judge when the banner should be brought backward, to avoid the descending feet of the equestrian, for space and time are important in a circus- riding act. But the most important to all concerned was the training of the circus horse. A balk while the rider was in the air would probably break a human arm or leg. So the horse was first taught to lope beneath an outstretched hand, then a whip, then a slender pole, until the bright-colored bauner didn’t bother it. The same process was fol- lowed with balloons, which are, to “towners,” paper hoops. After the horse learned to lope under them, alone, the rider got upon the horse’s back and, after many circles in this style, stood up and somersaulted through the hoops. Of course none of the results here touched upon were achieved as simply as this description sounds. Shy- Doing a Back Somer- sault, One of the Amaz- ing Feats Which Have Helped Make May Wirth’s Name Famous among the Circus Fans Who Watch Her Risk a Broken Neck

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POPULAR MECHANICS 263 ing, balking and many falls accom- pany the dull and tiresome routine in any training barn or circus tent. \ principal horse can be taught to hurdle just by touching it on the withers with a foot or riding whip.

By curbing it, it can be slowed down if it shows a tendency to lope too fast. Carrots and sugar before and after a performance make it more tractable, if it has an inclination to “cut up.” And how a rider hates to lose a horse! Not because they are worth more than $1,000 each, but because new ones are so hard to find, whether they be finish horses, which merely run, or principal horses which canter or lope, hurdle and keep a steady gait. Circus riders may have property and money and diamonds, but they measure their riches in good prin- cipal horses. They'll stay up night atter night to nurse a sick one, for the rider's kingdom is his horse.

a ote» _ oo -- SS a —— i a rR. <ieae oe , Fe ° x Phil Wirth Stepping off a Bareback Horse, and One of the Circus Equestriennes Taking the High Bars on a Trained Jumper; Circuses Have Always Been Famous for Their Fine Horses

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264 POPULAR Assembling Lumber Pieces in Convenient Shipping Package after Finishing with Special Saw LUMBER SHIPPED IN PACKAGES TO SAVE WASTE AND TIME Introduction of a special saw that cuts the ends of boards as smoothly as a plane finishes the sides, has made it possible to prepare and ship finishing lumber in pack- ages. Each board is perfectly squared, saving handwork, eliminating waste and the substitution of inferior grades on the job. The package is made by slipping a fiber cap over each end of a group of three to twelve pieces. The saw is filed and set by a new method, the teeth are finer and the saw runs faster MECHANICS TELESCOPE WITH GIANT LENS TO REVEAL NEW WORLDS With the aid of the telescope, the cam- era has made approximately 1,500,000,000 stars visible on photographic plates, while but a few thousand can be seen by the un- aided eye. Many more new spheres will probably be revealed with the constantly increasing size of the lenses of the giant telescopes used to sweep the skies. In the opinion of Dr. Francis G. Pease, of the staff at Mt. Wilson observatory, a tele scope with a twenty-five-foot lens is not impossible in view of the increasing im- provements in glass making and grinding. The mirror of the present telescope there is 100 inches in diameter. A twenty-five- foot lens instrument would cost at least $9,000,000, he says, and an endowment of $3,000,000 would be needed for its main- tenance and operation, while a special lo- cation would have to be found for it to escape atmospheric difficulties arising from searchlights in the neighborhood. One of the troubles with the big reflect- ing mirror of the present telescope is that it bends in the heat of the sun. WIRE-CARPET CONCRETE FORM IMPROVES CEMENT FLOOR As a combination form and reinforcing material, a steel-wire mesh, with specially constructed backing, is suitable for ce- ment floors, stucco and plaster. It is said than ordinary mill equipment. Every tooth travels a true circle and does its full share of the cutting. The unit is operated by an electric motor and is simple to use. An additional feature of the package plan is that lumber is more quickly inven- toried and handled more economically. @Tin may be re- to save concrete and eliminate the need of wood or metal forms, act as insu- lation against sound and to increase the strength of the ce- ment, as it helps re- tain the original amount of water, thus insuring bhet- ter curing. The fabric is quickly placed over the joists for laying the floors, as it comes in conveniently handled rolls. It is duced to dust by extreme cold. also suitable for use Applying the Wire Carpet as Reinforcing for Con- f crete Floor; It Also Serves as Insulating Material on roots,

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POPULAR MECHANICS 265 ELECTRIC PAGE MAKES BOOKS “TALK” TO BLIND Blind and hose having defective or persons, ailing evesight, may en- ov books in spite of their andicap with an appa- ratus recently devised by Robert E. Naumburg, an eastern inventor. It liter- lly makes books “talk” translating the print No special type is used and no pho- nto sounds, nograph records are em- Any printed made to. talk, enough, the ploy ed. book is Curiously through the machine, producing a contin uous buzz which is amplified in a loud speaker, When the light ray strikes the black letter, the current ceases, The result is a “sound pattern” 1, mixed for every letter or char acter so that with prac tice they may be rec ognized bv tl A large “ has been devised for the e listener learning chart” Above, Mr. Naumburg Giving a Lesson in Reading on the “Talking-Book” Machine to Toivo Laminan, and, Below, Student Showing Mrs How Letters Are Recognized on the Panels talking is done only where blank spaces occur on the pages. The instrument combines principles ot the redio, the light-sensitive cell and the televisor. A book, in ordinary print, is placed in a special holder and a tiny ray of light is directed on the page, the ap- paratus being adjusted so that it can be As long shining on the moved along each line of print as the beam of light is white paper, an electric current flows Naumburg use ofa pupil or student of the system, through which he can himself reproduce these pat terns by mechanical mean HONEYCOMB FIFTY FEET LONG FOUND IN HOUSE WALL Workmen ret Stock- ton. Calif.. not long ago, found a honey airing a house in one of the erround to and honey. comb fiftv teet long inside walls. [It extended from the the roof and was a mass of bee

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YS VA o Not many years ago, the phenomenon of a new star would have caused wide concern. The split- ting of a heavenly body would have struck terror to the hearts of millions. but the astronomers went calmlv back to their telescopes, for they knew that the break, whatever its cause, would not affect the earth—that it actually happened many vears ago, anywhere from 300 to 1,000. Nova Pictoris is so far from us that it has taken light, speeding here at the rate of more than 186,000 miles a second, centuries to reach us. The split was a new and wonderful discovery here, but to the heavens, it long had been a matter of history. By PAUL PADDOCK & STRONORERS, peering through a +4 big telescope in Argentina recently, discovered the latest mystery of the heav- ens. “Nova Pictoris,” a new star, found in 1925, had split in two. Word was flashed to the Union observatory in Cape Town. Scientists there trained a twenty- six-inch glass on the star. They, too, saw the wonder. The spectacle was without precedent. The breaking of a star has never been seen before, according to Dr. W. H. Steav- enson, president of the British Astronom ical association. New stars like this ap- pear from time to time, five having been observed in the last ten years. They flare up suddenly, glow with intense brilliance, aV »f a few rs ¢ > ™ Mr. Lee Taking Spectroheliogram of the Sun at Yerkes may be for but a few hours, and then sub Ma ee anne RG. Pease at Mt. Wilson's 100-Inch side or disappear. Reflector Telescope 66

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hes © The Illustrated London News Hundreds of Years Ago a World Blew Up, Probably after a Collision of Two Suns, But the News Just Reached the World When Astronomers Saw the Star Nova Pictoris Split in Two “The skies are filled with baffling as that of the said George C. Blakslee, who supervises the Yerkes “One of the first impressions we mysteries as new stars,” photographic work at observa- tory gain of the heavens is a sense of the enor mous distances involved. They are in- comprehensible, but comparisons help to grasp them. We are living in a day of rapid travel. Suppose we wanted to take a trip into space in an airplane and the Flying at the rate night journey were possible. of 200 miles an hour, and day, it would take us six weeks and five days to four years to get to to go to the reach the moon, fifty the sun, and 13,329,625 vears nearest star It takes light tour vears to reach us from this

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POPULAR MECHANICS —— A Mystery Eruption on the Sun, Which Was Observed While Tak- ing Pho Height t ographs of It in 1919; the Flaming Canopy Rose to of 410,000 Miles; Dot Shows.Comparative Size of Earth a you see tonight from Orion. started at about the time of the Crusades, “Millions of stars are so far away and the light from them so faint, that the unaided eve ca; never see them. Che telescope has pushed the frontiers of th heavens back far beyond the dreams of the earliest astrono mers, but we owea debt almost great to the camera, Astrono: is one of the oldest sciences, but star photography is of comp: tively recent birth You might say that it had its beginning with the introduction of the dry plate. Prof. Henry Draper, of the Uni versity of New York. made t] first successful star photograph vard observatory, a picture was made of the moon. It was cor sidered so wonderful that it wa exhibited throughout the east and then taken to the Crystal Palace In London. “Today we may be inclined to smile at this picture, for many far more complete and better in every way have been taken, but these early photographs are of in- estimable value because thev give us a tangible basis by whic studies can be compared and any changes noted. Taking pictures of the stars is a laborious and highly exacting procedure. For one good plate, hundreds may be failures. The star photographer | hardships of winter and the heat of summer, for his observatory dome must be kept perature of the outside air te pre serve the accuracy of his instru ments and so as not to distort the vision. Negatives must be developed with the utmost. care and precision to insure accurate reproduction of every detail The big telescopes must be nicely fo- cused and kept in constant ad justment to compensate for the t} + rotation of the earth. This is ex-

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POPULAR MECHANICS 269 ceedingly important when long-time expo- ures are made, and prac- tically all star photog- raphy falls in this class. \ single plate may be ex- hours and sometimes on two or | osed for more nights in order to far-distant stars. Giving long time enables he camera to record ‘see’ for us thousands of stars that our eyes could never de- tect. The faint rays of light keep ‘tapping’ away plate until they make their little mark, a dot that shows a star.” on the [maginea camera weigh- ing twenty tons, with a Above, Star Cluster of a Million Suns as Large as Ours, and a Three-Night Exposure of Hercules Cluster from Negative Taken at Mt. Wilson lens forty inches in diameter which weighs a little less than 1,000 pounds, with a focal length of sixty-three feet, that can be ex- tended nearly ten feet when special at- tachments are used, and you have an idea of the giant refractor telescope at Yerkes observatory as it is used for photographic work. In spite of its tremendous weight, the long six-ton tube is so delicately ad justed and balanced that it can be moved with one arm, but, in operation, it is fo cused electrically with accurate indicators, One of the most important features is the clockwork mechanism which corrects the position of the telescope with ence to the refer rotation of the earth. Its glass pointed exactly star, regardless of the years keep the big on the earth's turning But in addition to this mech anism, an assistant always wot the observer wl o = being taken to keep the telescope with perfect accuracy, accordi1 lines on one of the evepieces. In winter time, astronomers and star : photographers at Yerkes observa aie , , , quently have to dress as warmly as polar explorers. Temperatures of thirty de yrees below zero, and colder, ire ot ul common in the big dome that rolls about on wheels so that any section of the sky can be exposed to the o] iss. The forty-inch telescope is used for photograph work more than for direct = 7 s, including a six-inch glass that can be quickly moved hunting tor ordinary vision purposes. Smaller lense about for comets, are tavored observations. lo make a star photograph the plate fully adjusted to the lower end of the big telescope, thus transforming it into a camera. Two interesting attachments are used for making special photographs of the heavenly bodies, They are forms of

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270 POPULAR MECHANICS practically every radio fan knows. that the lights disturb the sending and receiy ing of messages. Quite recently an or ganized effort has been started to learn more of the effects of these spots. Ob servatories in this country and in other parts of the world are taking pictures of the sun in connection with careful weather observations. By comparing all the facts obtained, we may have a much _ better basis on which to make long-range weather forecasts. For instance, if it is found that world weather changes with the sunspot cycle, these changes may be predicted in ele en-vear inte! vals, for that is the duration of the spot period. They increase in number for about eleven years, 1 } reach a maximuni the spectroscope, nstrument which splits light into its different elements. The spec- trograph makes such a light picture of the star, It shows and then subside until another ‘out cropping’ ot spots in great number Occurs eleven yeatTs or so later. “One of the most remarkable of the sun pictures was taken by Prof. Edi- the body, not as a round object, but as a curious pattern of dark and light lines. By studying these marks, the astronomer can tell what ma- terials are in the star, whether the body is new or old, whether it is going toward or from the earth and about how fast. Similar light studies of the sun are made, for this is the time of the maximum sun- spot cycle, a phenomenon that occurs once in every eleven years or so \t least five spots can be seen with the un- aided eve by looking at the sun on a clear day through a piece of smoked glass, “The camera may help clear up some of the mysteries of these sunspots,” Mr. Blakslee continued. “We know that they are forms of electrical cyclones of tre- mendous intensity and size, and just now, thev are of special interest to us, for we are trying to find out what connection they have with weather conditions here on earth. We know that they have an effect on the northern lights and these, in turn, cause atmospheric disturbances. Not long ago, many telegraph lines were out of commission for a short period dur ing an unusual activity of the lights, and Contrast Upper Photo of Moon with Lower, Taken in 1841, the Oldest Astronomical Photograph; Center, Spectrogram of a Star son Pettit, in May, 1919. It was at a time of the maximum spot cycle and he had no- ticed a peculiar cloud hanging above the sun. The next dav, he concluded, some thing unusual would happen. He was right. With the assistance of his wife,

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POPULAR MECHANICS 271 he took sun pictures as long as he could. He was richly repaid. One of the most curious hap- recorded was preserved for all time on his plates. A huge, flaming canopy suddenly rose far above the sun, dipped and again and, finally, when it had reached a height of 410,000 miles, it vanished. Photographs the next day, showed not a trace of the strange specter. It doubtless had some con- nection with the penings ever rose sun- but no one knows just what caused it, where it went or what it was. “In recent star photography has become of still further impor- tance through the intro- duction of plates that are sensitive to the infra-red and ultraviolet rays. The infra-red are spots, years long rays that penetrate mists and fogs, revealing what is behind that, with thei them, so aid, we may be able to pierce the shrouds of mystery that hang about some of the planets. traviolet The short ul- rays reveal details that cannot be registered in ordinary light. We are learning more about Mars by means of special photographs of this kind. Opin- ions differ as to whether there is life on Mars at the present time. It seems wholly probable to the astronomer that there are thousands, perhaps millions, of bodies out in space that do support life in some form. At least, it is difficult to believe that our globe is the only abiding place of life when the heavens are filled with bodies, millions of them many times larger than our earth.” WEED LEAVES LIKED AS FOOD IN EASTERN MARKETS Leaves from the early blooming mus- tard, a weed that grows in abundance in California, are markets in shipped to the eastern fancy cartons and sold for How Sun Appeared April 12, This Year, through Yerkes Observatory Tele- scope; a Maximum Spot Cycle Is Now at Its Height greens. Pickers are sent out through the fields in late February, have matured when the plants sufficiently, to gather the leaves, which are graded according to size. packed in small boxes lined with oiled paper and shipped in cracked ice with other perishables. MUD CLAMPS FOR AUTO TIRES PREVENT GETTING STUCK Quickly clamped to the rear auto mobile tires, a pair of metal hooks af ford traction when the car sinks in a mudhole or other soft spot. They do not injure the rub ber will not come off and the automobile out help lift of the mire. The clamps are made for both balloon and small tires and are easily carried in the repair kit.

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272 POPULAR Treating Lawn with the Renovator, and Close View Showing the Arrangement of Rotary Cutters RENOVATOR TO CLEAN LAWNS REDUCES HAND RAKING Clumps of foreign grasses that endanger the lawn are easily broken up and the soil loosened or prepared for further seeding with a motor-driven renovator now on the market. It has a group of rotary cut- ters which can be raised or lowered ac- cording to the depth of the cut desired and are propelled by a small gasoline en- gine. The unit raises the runners of some of the grasses so they can more easily be cut with the mower, breaks up the crust and stimulates the growth of the desirable planting by cultivating the ground, RICH AMBER MINE GIVES WORK FOR ENTIRE VILLAGE Nearly everyone of the 800 inhabitants of Palmnicken in Prussia is employed in the amber mine there, said to be the only plant of its kind in the world. The spot has been famous since the days of the ancient Phoenicians, when amber was used in trade. It was usually dredged up by fishermen along the Baltic coast, but recently has been dug out of the blue clay. The, mine yields nearly annually, but only about one-half of it is suitable for beads and ornaments. The rest is ground into powder to make sands of years ago. MECHANICS pressed amber or is melted and distilled for other products. The most valuable pieces bear the name of “sauerkraut” am- ber because of their pale-yellow tinge and the markings suggesting strands of cut cabbage. The material is found in a wide variety of shades, and many pieces con- tain the preserved bodies of insects, which became imprisoned in the sap of the conif- erous forests that flourished here thou- It is this sap, in pet- rified form, which is so highly valued as the amber of today. SEVEN-TON CONCRETE BRACES HELP CURB FLOODS Concrete braces in the form of a three- cornered pyramid, each thirteen feet high and weighing seven tons, are effectively used in California to strengthen the banks of the Santa Clara river during flood times. The chief advantage of the units is that, even if they tip over, they offer a barrier, as a broad base is exposed re- gardless of how the skeleton falls. Drift- wood lodges against a row of the units, gradually silt and sand accumulate and, in time, this embankment, made secure by the concrete braces, forces the river back to its old channel. 125,000 pounds © Concrete Braces Used to Collect Dirt and Brush and Help Stop Floods; They Are Difficult to Upset

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POPULAR MECHANICS 273 NEW HELIUM PLANT | FOR MILITARY DIRIGIBLES To insure a constant helium, the non-inflammable gas used to inflate the bags of lighter-than-air craft, the bureau of mines has closed a contract for the establishment of a large plant in Potter county, supply of exas, It is proposed to xtract the helium from the natural gas in the re- ion, cooling it to 300 degrees Fahrenheit be- low zero so that all its constituents except he- | lium are converted into | liquids. The valuable gas _ | will then be drawn off and compressed in tank cars or steel cylinders for hipment. The remai: ing liquid will be restored to a gaseous state for use in heating and other pur- After the natural gas has gone through this process of extracting the helium, its qualities as a heating agent poses. are said to be appreciably improved. SPRING TO HOLD VALVE CAP PREVENTS LOSS Quickly removed or replaced, a tire- valve cap, used in Germany, is held by a spring so that it cannot drop off when taken from the stem This saves time while inflating tires and also keeps the cap from becoming dirty, as usually happens if it falls to the ground. @ Whenever you find that you wish to know more about any article in this maga- zine, write our Bureau of Information. Showing How Easily the Swimming Skiff Can Be Lifted, and the Unit in Use; Note the Foot Paddles SWIMMING SKIFF SAVES LIFE AND AFFORDS SPORT Supported by special floats and _ pro- pelled by means of paddles, worked by the hands and feet, a light-weight skiff has been introduced as a life-saving unit and to provi le sport in the water, It is easily managed, a number of them can be stored in mall space, i d col siderable speed can be developed. \\ | e7 Ivit Y on the } ', the operator’ ead ell out LIGHTING FOR FIFTY HOMES IN GIANT ELECTRIC BULB ry Three feet { F » inche diameter, a huge bulb for airport lighting and other spect purposes, produces illu 1 jan | EN t to ! t eeded f Tr itt e1 e home ore oO (x eral Electric comy report. It will have a life of 1,000 hour e thirt kilo it mowe}!l bull ] | 9 in ave e lite ) bu tel > TD vent n elting tf the elas t himney ha . ‘ . een fitted on top of the imp,

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U. S. Geological Survey Engineers Chartin Itilizing Its I tv-five engineers ot the geolog cal survey into a series of daily adventures +] t 4 ld ) ] > tl = 1, ‘ 1% ) ; at would Make weli- vl any movie tunt man envious. Within the space of a few weeks, they mav be called upon to uspend themselves from a cable car above mE + a raging torrent: dig holes through ice stream’s velocity; penetrate the ultra-arid regions of the great southwest. or risk their necks while surveving in the vicinity of rocks that tower hundreds of feet 1 ¢ above the water level. Bear in mind that these are tvpical, not unusual, cases For practically ll the surveys engineers are field men. wor shiping the ver name ot vate the greatest of all the world’s needs Ouench- ing thirst, offering transportation and powel transtorming arid wastes into bountiful fields, it spells health, prosperity and progress to every one. Veritable wizards in ingenuity, quick- fire judgment, inventive skill and action are these men. Thev must be. for theirs is the man-sized job of supplving the en- tire nation’ with reliable data regarding our water supply Millions of dollars an nually are saved, directly or indirectly, the Depths of the Grand Canyon of the Colorado, to Map the tential Five Million Horsepower oug the et ts. Record ilready ( ected have been the basis of most irri- tion projects in the west ot modern development of power, both hvdro and team; of water supplies for cities and ndustries, and of studies for sanitation, drainage flood Co ntrol and 1 ivigation. Located at strategic point along the edges of our major streams are about 1800 measuring stations, devised to probe conditions of surface water—that is, the velocity and average rate of flow of our rivers Each station is a rood ized con- crete hut or shelter. Ordinarily it con- tains the follo go S quipment: a steel cable to he above the tream from points along the shore and a Caf that runs along it and Into which le engineer mav go and two ingenious devices, per- fected after ‘long vears of tudy—the water-stage recorder and current meter. [The recorder is a permanent fixture of each station, being installed within the shelter over a-well connected with the waterwav whose surface is to be measured The newest type shows the fluctuations in stages of the stream by means of a graph from which the height of the water at anv time mav be read. As for the cur- —_

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‘nt meter, its purpose is measure the velocity stream, and s may be done by the hserver in two ways, ther by suspending the levice by wire from the ible car, in case the tream is deep or violent, by dropping it from a dl. It t heel, a given consists of a containing five which revolves impact with the lowing water. On impressive streams, Colorado, cups, upon uch as the where depths as great as fiftv feet and velocities up to fifteen feet per sec- ond must be measured, using the water meter hazardous. In such case no less than a hundred pounds of lead are necessary to hold the meter in proper position against the torrent, and long as 1,500 feet must be used at dan- gerous points. Though hecomes cables as — the observer's perch may be lofty, therefore exempt from dangerous risks, and seemingly he is liable at any mo- ment to be jerked from. his position by the terrific impact of floating logs and other drift against the meter. Mountain climbers extraordinary are Many survey engineers. Their work car- ries them to the very summit of our loftiest There, with the tools of modern hydraulic engineering— the map and the surveying rod—they cre- ate great artificial lakes, stepmothers of rivers, peaks. magic Few know of, but many gain by, the fact that, in regions of arid land, engineers often can unused increase the Measuring the Current Flow of a River with a Meter Lowered through Rows of Holes Cut in the Ice mean flow of a river some three, four fivefold and more, by means of expert planning and creation of storage lakes at the headwaters. Notable developments in which far-seeing survey among the recent large-scale engineers were directly or indirectly con- cerned, was the Salt river project in Ari Here thev outdid Mother Nature herseit by ZONA. their help in arranging an art} ficial lake. or reservoir between seven and eight miles long For many miles the available water supply was increased some- thing like three times.

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~ 240 POPULAR Sucl vreat storage basins are not like the popular conception of the average reservoir—w hicl merely a nice bit of a man-made lake, Instead ley are many-shaped manv-sized, following in contours of the countryside. At t ey times, ‘ ae | + stretch some twenty, thirtv and even several | hundred square n 1 1 7 they are regulated for the most part by a single dam situated at the “nec the bottle,” or headwat If the evervday work of our surface hydraulic | engineers tends to be ittle short of amazi i its results, no less so is that of the underground with discovering. devel- oping, protecting an making more accessible resources of the country. As Dr. Oscar E. Meinzer. for the past fifteen vears } the underground water i G geologist in charge of the underground- water activities for t le survey, phrases the situation: “About 55,000.000 people in the United States, or about half our total pop- from wells.” Small wonder Uncle Sam is interested i: ulation, obtain their water inderground water! lwo main classes of wells are particu larly emphasized by the survey investiga 17 tions: the ordinary well. or that which is and the artesian well. pumped which the 1 dictionary describes as “a spouting wel bored down to the point, usually at a great depth, where the pressure is so great into the air.” as to force the water up These wells mean that miles awav. at a considerably higher eley tities of been ation, vast quan water from rain and snow have sandstone rocks which underlie t ion, and then through the Thus, drill penetrates the deep-seated rock and seeping into the porous he reg have percolated rocks far down into the earth when man’s MECHANICS BARSTOW 6 DAGGETT Gm be ig a . a 4 eclogical Survey Signboards in the Southwestern Deserts Point the Route to Every Dependable Spring 1 water tormatio1 s the pressure ground forces the water into the air. hear Locating these valuable artesian water . , he most important jobs supplies is one of t of the government geologist, particularly in the great stretches of country in the vest and southwest where arid conditions prevatl. In the case of a 3,000 foot deep ] ,~a SUTVEV Geolo- , } within > Ner ‘ent ¢ +) fist guessed l one per Cé Ot the : . , ‘ a ictua depth. His trained eve glanced 1 earchinel, at the reologica maps, W hich. bv the vav. he himself had constructed after manv months of pains > - . | iniIne Tresearci Indeed, the underground water geolo vist, by virtue of expert knowledge of strata, can approximate the extent and location ot our unseen water resources with almost the same degree ot accuracy lic engineer with respect Nor does he have to be on the actual scene of opera- as can the hvdrau to surface water alwavs

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POPULAR MECHANICS 277 ions, as the following example illustrates : During the World War, an army officer, newly installed at a post in California, vired the survey for advice regarding the lrilling of a proposed deep well at his vase. Already he was working out plans x the purpose. However, he seemed xious for the expert opinion of the vreologists. Terse and to the point wa their immediate response to the wire. Upon examination of reports and maps f the region, they found that the officer as about to try the feat of drilling hrough solid granite! A sizable southwestern city, owing to a prolonged drought, as suffering from a erious shortage in 1 j water supply. All leve were unable 1 tT cre 1) ‘ he water th to get any wate at pre- : ' a umably could be ob- whatsoever for pro longed periods. A remedy must be tained from mines, shallow wells and tunnels of the city found immediately, waterworks proved “3 the city was woefully inadequate, panning tO pUtr- and some of the ase a spring some houses on the higher en miles away, vhich at the time at about 145 gallons a was ftlowing ~ minute, and to lay a pipe line across the mountains trom the spring to the city ~ Che project would cost about $120,000 and would involve serious engineering difficulties. Fortunately, a survey geologist was called upon to help. Within a short time he found two sizable drilled wells within he city limits. One flowed about seve gallons a minute and the other wasn't € en b 2° i So Lil i ¢ could d Covel ( ] é | 1 ¢ 1 hee y é nim \ ) re hee d led in the atte rt »geta tel but it not occurred to e t the i V el be 1 creased ma | e process of pumping lheretore, the urvey geo] cist lost no t l@ in ad 11 tl e to authorities to install an air lit, wl force inte er out ¢ the rround considerably taste t nits normal cout permits, in each well Results were instantaneous and grati Measuring Deep Wells, and Charting the Current Flow, as , F , in Winter and Summer, with an Electric Meter Iving. kor 2 period of three weeks both

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POPULAR ME ¢ ‘HANICS

- ( Swings above the Rapids t: ten time hn average, During this

( < { LIne w 1] 1 ot ~- ro ] ( £ well ed about ninety gal- , ; ye as e hitherto idle well ns a minute, w ave about seventy gallons a minute. sources which h bother water O Valu had thought u tw were wort obody g about vielded as much _ water pet inute as did the spring across the moun tins, and their use at this time meant a ng of at least $120,000. RUBBER IN TIRES PROTECTED BY CHEMICAL Greatly increased mileage from automo bile tires is anticipated from the use of a rece! t] d Veil ed chemical preparatio: ic] iid to prevent the rubber from oxidizing in the air. The substance is added vhen the ibber iS compounded nd is not affected bv vulcanization. Ac cording to report tires containing the chemi i] will not deteriorate throug “tion \" hile in storage or car ried as spares I] fail only through samples treated wear or damage, In tests, a Cable in a Traveling Seat, Torrents Have No Terrors for the Hydraulic Measure Depth and Current Flow of the Stream ith the preparation ire aid to e re tained their elasticity indefinite t is ntended for use in all kinds of rubber products, including bands, fruit-jar rings,

vashers, garden hose, hot-water bottles and all sorts oft me Ided eoods DESK FENDERS SAVE SILK HOSE FROM STRAY SPLINTERS Fenders to protect the stenographer’s silk hose trom the splinters that lie in wait along the corners of desk legs are the newest ac- Cessory for the of- fice. The _ fenders, metal strips Copper- plated to blend with mahogany k desks, have a curved or Oa edge to fit over the sharp corner of the desk leg. A screw driver is the onh tool needed to in- stall them.

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eX POPULAR PATENT INSURANCE PROTECTS INVENTOR AND MAKER For the protection of inventors, manu- icturers and others interested in patented ticles, a new form of insurance has been nounced by two eastern companies. The two fi of me tor detense and indemnity in the event jlicies provide rms coverage, it infringement suits are brought vainst the policy holder, and the other ir bringing of suits when his rights are is designed to olated he of all persons con ed in a patent, including the inventor mself, the manufacturer, the seller and e€ use! \ primary function of the plan to alleviate the timidity that now not frequently deters manufacturers from oiting desirable patents. MUSHROOM ANCHORS TO HOLD LANDING FIELDS AT SEA Special anchors have been devised by eastern inventor to hold the “floating land” landing fields for airplanes. They re of cup or mushroom shape and are intended to grip the bottom of the sea partial vacuum he bell-like portion of through the which wi be within t the anc A number of these, it is be- lieved, fixed to a rock bottom, would keep formed hor Model of Mushroom Anchor Intended to Hold Floating Island Airplane Ports to the Bottom of the Sea the landing field or seadrome from being torn away from its moorings. MECHANICS L of Decorations Showing Bonnets Pillar Sleeping Porch, with Changing Styles in HISTORY OF BONNETS IN CLAY NOVEL PORCH DECORATION Changing styles in women’s hats fut nished the theme for unique decorations on the sleeping porch of an eastern man's home. On the tops of the railing posts he modeled the heads of women wearing bonnets in fashion during the 60's, a mode of about 1900 and the turban of today. CATNIP AS LURE FOR BOBCATS HELPS PROTECT GAME Catnip oil is being used effectively in trapping bobcats, mountain lions and vnxes that destro betwee $20,000 000 id S30.000.000 wo re and ock in the estern te eacl eal It | aced on trap ) 18) med bait a | e¢ to att! t the bea nn t does the do tic cat é yvernme planted i cat »L el Ar] to \ to provide oO rr tne e ( C t the first trials proved so successful tl larger crop were grow! Saratoga Springs, N. Y. Last ve te i t biological urve caught 46 ) 3.677 bobeats and forty-one Ivnxes, hundred being victims of their love ot ip

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280 POPULAR MECHANICS TORTOISE FARMS IN DESERTS TO SUPPLY FOOD iitvy specimens of the giant land tortoise have been brought to this country trom the Galapa- : ] + os islands to determine if they can be raised on the desert inds o the est The species 1s p1 marily i cactus ¢ € accordin to Dr. ¢ arle H. To end, of the New York aquariut but it O feed ( Ta d evel ble oO! differs t inds. It lu a meat Testing the Extinguishing Power of Different Chemical Mixtures on Blaze of oducer long been Oil, in Special Cabinet Where Temperatures Were Measured : - . , ; overiooked, he qaeciare FIRE-FIGHTING TESTS HELP [he tortoises sent here are infants, the REDUCE LOSSES EEE PRE ARON SNE ee 4 tub In captivity, this variety ofte dou For hundreds of years, man has relied — bles it eight annually for a time and chiefly on two principal methods of com has been known to reach a eight of 400 bating fires lowering the temperature by pounds in fifteen vear Wate ( other e the blaze t ub + +) vo lh a saw cae nen adn cea by the NINETY-FOOT TRI-MOTOR PLANE Sin Gekt pte ictal cimih. t f.cht- FOR TRANSATLANTIC FLIGHT ng d fires difficult to manage Undiscouraged by many failures at fly- Vv ordina r s Interest effects ing acre the oce: on ¢ neers ive been observed 1 tests it these re buil @ ne hip t ch they substance Si r t t cont large hope to make trat I ti¢ pl amounts of oxvgen were discovered to tical. One of the most rece of these be effective agents putting out fires, if tl proper amount of water was mixed with them In making the trials wit] the different chemicals, a . ‘ special testing « ibe P : is emploved n hich ‘ , refu \ mea ired Ol t 1 ] ] 1 ire directed o blaze of rasoline unde pressure. Different solu tions of the substance tried until the most ef fective one is found. Ac curate temperature-mea uring apparatus was used 1 1 in connection with the cabinet to duplicate ac : iain Front V y of the French Tri-Mot¢ lane for Transatlantic Flig tual fire conditions. lew 1¢ French Tri-Motor Plane for Transatlantic Fli Carry Nearly 1,700 Gallons of Gasoline

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POPULAR MECHANICS 281 craft is of French design. It has a wing spread of nety feet, is equipped h three motors, each of 180 horsepower, and carries 1,638 gallons of gasoline, besides seventy- four gallons of oil. There are seven tanks for fuel. he plane will carry ra- dio-transmitting and re- ceiving equipment. SEEK LONGER LIFE FOR PAPER MONEY By increasing the eth of the fibers, the yvernment has prepared paper currency that will last about twice as long the old kind. A bank te can be folded 5,000 ( in two directions out separating the bers. Strengthening the paper with glue sizing . ai tried at first but with less success as the paper uffered in the process ol printing. Better results were obtained by improv- ing the fibers. Experiments are now un- — “SPT RIT”-PICTURE PROJECTOR — letermine if cotton can he nced ce wav to determine if cotto Ca pe used TO AID TEACHERS as a substitute for linen without impairing the qualiit of the paper. C\hiect of mat Lond ] ne - AUTO WINDSHIELD KEPT CLEAR ‘| | ay G WITH GLASS PROTECTOR scientists have developed. It produc 1 frost are prevel ted trom arrangement ot 1 rrol | f ‘ ’ Moisture ane ) collecting on the inside of the auto wind- — special illumination oan bserver. 1 shield by means of a plate of clear gla effect i ewhat like fastened to the called interior and form- ing a dead-air space ( ( between itself and ( the shield. It is held securely bv a half ‘ inch rubber mold ' ing, so that no drill- ing or cutting is re- quired An addi- tional feature is that it doe not inter- owe fere with the w iper. a Brovactes In ' led s wi g he Clear Space eft ue to Dead-Air Space under Glas

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282 POPULAR MECHANICS WIRELESS-CONTROLLED BATTLESHIP, STEAMING CONTROLLING AERIAL ON 4 TARGET SHIP ee ee \ ————" WIRELESS RECEIVER/ TUNED TOA CERTAIN | WAVE LENGTH ——> THE ELECTROMAGNET CLOSES “2 THE CIRCUIT BY CAUSING THESE POINTS TO COME TOGETHER | |THE CURRENT FROM THE RECEIVER THUS SUFFICIENT ENERGIZES THIS STRENGTH 1S OBTAINED ELECTROMAGNET > s _-FIRING SHIPS TO RUN ELECTRIC MOTOR WHICH OPERATE THE GEAR CONTROLLING THE RUDDER ENGINES, ETC. THIS CIRCUIT IS RENDERED ae POWERFUL BY STORAGE BATTERIES fe AN ELEMENTARY DIAGRAM SHOWING HOW AN ELECTRICAL RELAY OPERATED BY A WEAK CURRENT CLOSES A POWERFUL CIRCUIT OF SUFFICIENT STRENGTH TO RUN ELECTRIC MOTORS i EF ng. = > 3”¢ SALVO “Se - "RANGE HAS BEEN sm SLIGHTLY INCREASED. THE TARGET HAS BEEN _ “STRADDLED” AND ONE HIT REGISTERED "9 pie on 15f SALVO DISTANCE OVER TARGET ONE MILE DESTROYER “SHIKARI ® CONTROLLING MOVEMENTS OF TARGET SHIP FOLLOWING ABOUT ONE MILE ASTERN THE “CENTURION” co a THE TARGET SHIP BEING MANEUVERED BY WIRERESS AS IF SHE WERE MANNED BY A FULL CREW AND BEING FIRED AT BY SHIPS. ABOUT 842 MILES AWAY Ws wages a Courtesy The Following in the Line of Experiments Made by the American Navy Some Years Ago, the British Admiralty Has Equipped the Old 25,000-Ton Battleship ‘‘Centurion” for Remote Wireless Control So That the Grand Fleet Can Have Actual Battle Practice without Danger

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POPULAR MECHANICS 23 ZO. WITHOUT A SOUL ABOARD, USED AS GUN TARGET - etsy 7 : | AERIALS ATTACKING DESTROYERS. 7,000 YARDS AWAY, AFTER FIRING THEIR TORPEDOES, HAVE TURNED AND. PUT DOWN A SMOKE SCREEN ‘* 4 j TRACKS OF a ~— THE TARGET SHIP “CENTURION, ae BEING ATTACKED BY ; Seen TORPEDOES AND BEING eS “\ REALISTICALLY MANEUVERED BY WIRELESS . ie a in a - a ~~ WIRELESS TELEGRAPHY CABIN "SHIKAR! CONTROLLING THE “CENTURION BY WIRELESS EE € London New After the Crew Is Taken Off When the Drill Ground Is Reached, the “Centurion’s” Captain, from the Bridge of a Destroyer a Mile Away, Maneuvers the Battleship by Radio t Dodge Shells from tt beyond the Horizon, and Thwart the Torpedoes of Attackin

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POPULAR Weaver, and Sample of Seamless Trousers Made from Burlap WEAVES SEAMLESS TROUSERS IN HAND LOOM Trousers are woven without seams from such materials as burlap and other cloth by an eastern expert who has had more than sixty years’ experience with a hand loom. Even the side openings for the pockets are woven instead of being cut. The garments have a neat appearance, CLOCK BUZZES WARNING OF ENGAGEMENTS To aid in keeping appointments, a mem- ory-jogging clock that gives an audible and visible re- minder of duties to perform, has been introduced. Around its face are forty-eight slots, one for each quarter of an hour, A tab, bearing a memo of the en- cagement, is inserted in one of the slots opposite the proper time and the alarm set. When the hour the clock vives a buzz, which sounds for five min- utes but ceases when the tab is removed. arrives, MECHANICS TONS OF EXPLOSIVES SHIPPED WITHOUT LOSS OF LIFE Last year, nearly 500,000,000 pounds of dangerous explosives were shipped in the United States and Canada without of life or injury to any person, and with a money loss of only $45, loss The record is considered largely due to the efforts of the bureau for the safe transportation of explosives and other dangerous articles, organized in 1906, Nearly 230 different kinds of merchandise are now listed by this bureau as requiring special handling to prevent fire and explosions. In 1907, explosives charged with seventy- nine accidents, fifty-two fatalities, eighty personal injuries and a property loss of nearly $500,000. were HOLDER KEEPS COINS SORTED SAVING TIME AND LOSS Coins of different denominations are kept conveniently sorted, Where they are not likely to become lost, and may easily be picked out, in a pocket holder recently intro- duced. This saves searching for the right coin, reduces wear on the pocket and en- ables a quick es- timate of the amount of money on hand. Beside the compartments for small coins, the holder has space for those larger than a quarter and for bills. KEY CASE WITH SWIVEL HOOK SOLVES TURNING PROBLEM A leather key container with the hooks mounted on swivels, so that the key in use can be turned without revolving the entire case or twisting a part of it, has been placed on the market. Each hook is mounted on an individual swivel disk that turns easily by itself. carries an transparent A leather flap card under a return .of lost keys, or identification of the owner. identification window to insure

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POPULAR MECHANICS 285 CAKE IN FORM OF SKYSCRAPER — #1 the voice is recorded and ready for WEIGHS HALF A TON ee. eee clic] re turd ] They built a skyscraper in three weeks has_ bee: ecommended especi in Spokane, Wash.. recently, but the voice and drat ti chools to enable the structure was of wood and pastry and the _ pupils to listen to their own perfor ce result was an enormous cake, a replica and so correct their erro of a bank building in the city. The cake weighed 1,100 pounds and was formed PypEWRITER FOR THE BLIND about a framework of wood. Its builders HAS SIX KEYS took out an insurance policy on it. - — Portable tvpewriter cross-word RECORDS MADE IN YOUR HOME ___ Pods, anda set with which children WITH PHONOGRAPH UNIT eee ee eee ee ca the Ct i¢ elk t ] A recording attachment for any make The typewriter has o1 ix ke vet of phonograph is now available for those prints every letter in the alphabet and who wish to make, the co1 their own records he perforat at home, preserve | é tem \ the voices of their > the headauartet1 loved ones or “can” he radio programs for ( lind future use. The unit otary pre operates on familiar 1 { 12.000 principles but re- e page quires no skill to ur | een re use. It is simply ceived from Swit attached to the ( 1. Former 1 phonograph, you chines turned out speak into the horn. Making Her Own Phonograph Record; the Attachment hut 4000 nage Is Easily Adjusted and Is Simple to Operate

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This Heater P and Generates Steam to Insure Cir- culation f Warm Much R

AN-j} QO eur all

ortable Electric Contains a Fan and Healthful Condition Air; It Uses About as | Current as a Flatiron and equires * Keep the Infant f king Its Thumb; Attachment Is Adhesive Tane re by

Little Attention m This Held

Windo Cleaner, with Brush and Squeegee, Also Has a Container to Hold Water So That a Pail Is Unn . Oe ‘om .< t Tools in One € an Tr yuble

aveler Who Wants Pure Water, This Electric Unit, Operated from Light ing Socket, Floats and Collect$ Impurities as a Scum Which Is Easily Removed For the Tr

The Handle of This Magnifying Mirror Contains a Nail File and a Pair of Tweezers, and Folds Up as a Support for the Glass on Table

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Food Press Is Easily Taken Apart for Thorough Cleaning 1 Has an Efficient Dasher Cross-Shaped Candle Sup- ort Holds the Candle Securely in Socket and Iso Catches the Drip- Pastry Cutter and Mixer, Invented by a pings; It Is Serviceable Woman, Saves Time and Is Said to Insure When Sticks Are 7 Lighter Crusts: It Supplants Hand Method Large for the Candle of Cutting Shortening into the Dough

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288 POPULAR MECHANICS PN | reaction with but little sulphur; smaller ones whose water is often acid and turbid, and a third group whose water con- tains lime and consider- able sulphur but is com- paratively clear and not excessively hot. GAS FLAME KEEPS FISH SHIPMENTS FROZEN Shipping fish in iceless refrigerator cars has been successfully tried be- tween New York and Fort Worth, Tex. The cars are equipped with Civilians Studying Army Maneuvers on Model Map; Problems Are Worked freezing apparatus that Out by Directing Hypothetical Troops over Mimic Battlefield “7 WAR GAME WITH MODEL MAP TRAINS CITIZEN SOLDIERS Civilians being instructed in some of the fine points of war, make use of a model map, like those employed at the war col- lege in Washington. The group is di- vided into opposing sides and the various moves to be made by a hypothetical army are indicated on paper. Hills, trees, rail- roads and other strategic features are rep- resented on the map. RAIN AND SNOW FEED GEYSERS IN YELLOWSTONE PARK Rain and melting snow help run the geysers in Yellowstone park, scientists have found. The columns of steaming water are shot up, not wholly by the action of subterranean boiling springs and vast steam chambers, but by rain water and melting snovw trickling through fissures in the surtace of the rock until they meet steam and other volcanic gases from a buried lava ma The water gets hot and when a certain pressure is reached, the gevser spouts. There are three main classes of hot springs and geysers: those sending out the greatest volumes of water, clear, very hot and usually alkaline in utilizes a gas flame and a special material which produces intense h the flame. No source of mechanical power is required, cold in combination wit and the compactness of the refrigerating unit increases the space available for load- ing by about ten per cent. FOLDING PEDESTAL BED FITS IN DRESSER DRAWER Instead of standing on four legs, a fold- ing bed, introduced by a California in- ventor, rests on a center pedestal. It is said to conform more nearly to the figure of the occupant and needs but little bed- ding for comfort. In a few moments, it can be converted into a wall bed or may be taken apart and placed in a bureau drawer. A special feature is that the sup- port revolves on the pedestal, making the bed suitable for use in a sickroom. Bed on Pedestal Instead of Legs Can Be Folded in Small Space and Gives Comfortable Support

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POPU FELLING GIANT CHIMNEY SHOWS SKILL Toppling a 700-ton smokestack, 04 feet high and seventeen feet diameter, is as easy as felling chestnut tree, if you know the ick, according to W. M. Barber eteran chimney thrower. He emonstrated his’ skill recently hen he wrecked a huge stack the Ohio State University inpus, bringing the big pile wn within a few feet of a build- ng without damaging that struc ire. Workmen first cut away the icks and concrete on the west ise of the chimney, since it was » fall westward, and filled the le with timber props. After the ipports were in place, they were covered with inflammable mate- al that had been soaked in oil. \ match flared, the pile was ig- ted and for nearly half an hour ig crowd waited while the chimney smoked. Finally, the fire-eaten supports began to crum- ble. A minute later, the whole tructure collapsed. An added thrill was furnished when a large crack broke through the base of + e stack and tore Zigzag toward le top, as the chimney fell PHONE SHIP AND PLANE BY DIAL SYSTEM Telephone messages to moving ships, airplanes and trains are now possible by the dial system, pro- vided the proper receiving appa ratus is carried. By the new method, which has just been de veloped, a subscriber sitting i his home might talk to a_ pas- enger on the “Leviathan” at sea, could get a message to the Twen- tieth Century Limited as it sped along or reach the “Los Angeles” while is was high in flight. The process permits linking of radio and land-wire systems and is not expected to supplant the existing land-telephone installations but merely to amplify them. LAR MECHANICS 289 Big Chimney Splitting Just as It Fell; Cutting Away the Bricks for Temporary Timbers That Were Burned, and Stack an Instant before Final Collapse

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290 POPULAR MECHANICS inconceivably minute, will protect a rat trom ricket when added to its daih diet. Dr. Alfred Hess, of hospital, New York, and Prof. A. Win i daus, of the University of i Bellevue Goettingen, Germany working toveti er, di COV- ered the remedy. Babies receiving from two to rout! n eral i day l the Bellevue ospital Clini ire iimost reg lar cured, accord ¢ To advantages of ergosterol over cod-liver oil is that it is both tasteless and odorless, so that it 1s easy to get children to take it. CHANGEABLE SIGNS MADE UP WITH LOOSE LAMPS Islectric sig 11 the ° ' , " torm ot pane vith per - . . 1 1 1 TOrations, 11 Vnici iet Testing Model of the Giant Seaplane Which Has Been Planned to Carry ters, numbers and de 300 Persons at One Time across the Atlantic ae can e irranged 1 SEAPLANE TO CARRY HUNDREDS with little trouble “A d changed at Re erg OVER OCEAN IN FEW HOURS have appeared in advertising de a pha- bets. euwuides Oo! other acce ( es are ransatlantic flights in nineteen hours needed, the legends being made wit! mall in a giant seaplane that will carry 300 per lamps which anyone can insert. A drug sons at one time, are planned with a craft cist, for instance, could utilize space and being designed by a New York inventor. Whether the plan will be a success or not, is being determined to a degree of cet taintv, by means of wind-tunnel tests on a model of the plane. These experiments reveal anv structural defects or faults of design, so that errors may be rectified. OUNCE OF RICKETS REMEDY EQUALS TONS OF OIL Irradiated ergosterol, a new remedy for rickets and similar bone diseases discov ered a vear ago, is so powerful that a sin- gle ounce of it i equal in effect to six = iia . —_— tons of cod-liver oil The substance Inserting the Small Bulbs in Board, and a Sample of ’ 3 = : ‘ : lluminated Design which is the parent material of vitamine i= oO potent that a twenty-five-thou- current required for a fixed sign, to ad 1+] { +11 . sandth of a milligram, a quantity almost vertise a different feature daily

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J Courtesy T S. Geol ical Surve In Summertime, the Sled Dogs Become Pack Carriers and Frolic Along as the Alaskan Game Wardens Cross Snow-Clad Mountain Ranges on Their Rounds TINE men, with a territory nearly a allows to police 586400 square miles of 4X fifth as large as the United States, land and wate 1 territory more than pread over an area almost as wide, a twice the size ot Texa and with a popu large part of it virgin wilderness, have _ lation, at the last e of but 55,036 brought the law to the Yukon district. lo police it. the nine have divi led t] The nine‘game wardens of the United mainland and the long chain of the Aleu States biological survey have been, since — tian islands into districts. The smallest ts 1925, charged with the great task of en 360 miles across, and the biggest 1.000 forcing game laws in Alaska, once a fur miles long Che latter includes the islands paradise where men have been accus of the sea, the active volcanoes, the valle tomed since the beginning to trapping made famous by its thousands of smol and hunting what they wanted when they — ing, steaming craters, the seal rookeries anted it, without regard to open or of the Pribilots, and the only way to covet closed seasons. it is by boat through some of the world Mighty rivers, tundra plains, ranges ot worst seas. mountains that include the highest peak Sudden storms and treacherous tog n North America, a vast chain of islands and the always present menace of treak tretching in a giant semicircle far out winds, the “willie-waws” of the nort! toward the shores ot Asia, elaciers, vol make the Aleuts a constant d inger zone canoes, alive and dead, the famous valley Small. stanch ocean-going boats, moderate of Ten Thousand Smokes, the home of in leneth,. but built with the tlaring bow the brown Kodiak bears, largest living deep draft and straight sides of the north carnivorous animals; all these and many Pacific halibut fishing fleet, are used b more come within the empire ruled by the seagoing wardens. just nine men. Some day, when the force On the mainland, the mighty Yukon and is recruited to full strength, it will num its maze of tributary streams, provide ice ber fourteen—the maximum the game law sheathed roads for dog sledges in winter

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292 POPULAR MECHANICS and lanes small tor teamers or canoes in Away fi rivers there are few trails, om the no roads, once the settle ments are left, and he main reliance In 7 only dogs as t for transportation. winter, the sled dogs drag in supplies, and in ummer they carry small packs strapped to their Pair « \ few horse pack f Frolicsome rains are used, but much of the territory the wardet cover 1s too 1 rough even for pack horses to get through | t Y ign. In such an empire it is easv for a man to drop from sight and never be heard of again. Not long ago, fifty men. in ten mi steamers, searched the Chichamin river for weeks without finding a clue to the fate of one of the yw ardens Five weeks before he had chartered a boat to make a hurried trip up the river. Under orders to exercise extreme care on his nussion, which was presumed to be a se- cret, he had also been directed to reduce expenses lat as possible, so his as renting journey indicated Yet and boat both disappeared, and no of a boat for the hurried something important had developed. man trace of either has ever been found. Until a few vear hunting in Alaska. ning s ago fur trapping and vielding ‘a return run- millions, What into the went practically unregulated, closed season there VW VA Wald \ dictated : eC! tirely by the trappers’ in Vas stinct against taking pelt-not vet in its prime Under such conditio1 the available fur supp! has dwindled rapidly recent vears. When the biologic survey took charge, 1 1925, it started with closed season on suc fast-disappearing specie as the marten and beave1 mi 4g eta: Be é ake oa Brown Bears, Largest of Their Tribe in the World, and a Dog Team Mushing Supplies over the Ice and a reduced bag limit on others, in- cluding trophy hunting for moose. Game regulation has never been popular with professional hunters, and in a region where there never had been law enforcement, the task of the wardens was enormous. But, according to Ernest P. Walker formerly executive officer of the Alaskan game commission, who helped put the new regime in operation, the wardens have es- tablished the of six per cent convictions where they went to court the penalties he record winning ninety- heavy offenders, and instilled order of things. with respect for new Chosen from the pick of Alaska’s trail ex- perts, the game guards are noted not only for being quick on the trigger, but like- wise for being level-headed and cool. Two vears after they went into action, the game regulations were strengthened by a rule requiring every legally taken beaver

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POPULAR MECHANICS 293 Bridges and Fords Are Rare in Alaska, So, Frequently, the Game Wardens and Their Pack Horses Must Plunge through Brawling Rapids, at Imminent Risk of Death ind marten pelt to be presented for the With a range in climate from warm inspection of the game commission or ummer davs, to winter blizzards, wh vardet and also demanding an affidavit e tne! mete iv ¢ pto Vy or SIXty from every trapper attesting the legality below zero, the work of the wardens i of | ( itch I Oo p (rie eport I The temptation to beat the law is strong, mg a ynie atrol 1 1 Bethe for a single marten pelt may bring $100 omewhat north of the Kuskokwim rivet ind a few aid away betore the seaso wn to the Br b 1 teé ot opens, later to be muggled out at d id tartin é sledge his ca ) to some fur buver, mav net a tidv sum. equipment and supplies over the sno \ beaver pelt brings, on an average, $20 ind ice A warm spell betore he reached and the trapper is limited to ten in south is destination melted the surface ern Alaska and twenty each season in the ind sottened the ice unt at 1 er cro 1orth ever ive that can be take nt no the d nee wlenret treatin nl. .veryv five that can De iken ou igs, e dog ea O Irie ‘ . | | ide the law means another S100 profit I ¢ ] ¢ ¢ \\ thie ( In making the round the wards ed, cro gy A on . . ° ° 9 *4 9° ‘ 1 utilize almost every form of primitive child's pla Coming d n trom the transportation, and now thev are begit uuntains through narro ror drop okin oe ” 1 F 43 oaks ee alt aa 1 +] , ing to adopt the most modern o them Ing rapidly owa e e 1 e all, tor flying is being established on a and creeks abound in rap nd there practical basis in the far nortl Phirty eno we ke b ch they odd landing fields have been cleared, and cal be crosse Even the navigabl several air lines are in active operation streams are dangerou and the mall On many trips the cost of an airplane is teamers that travel them during the short cheaper than travel by dog sled. for weeks ummer season are provided with enor of painful work may be compressed into a mous timbers which can be thrust out few hours by air. trom the sides to keep them from being

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294 POPULAR MECHANICS An Alaskan Game Warden, with Well-Loaded Sled and a Dozen Dogs, on the Trail; Away from the Settle- ments, Dogs Are Still the Main Reliance, though Reindeers Are Coming In whirled into the river banks in bad gorges. Not all the adventures of the game war- den are with poachers or natural enemies. Occasionally, the game they are protect- ing takes a dislike to them and _ other animals show fight. One of the force was badly mauled in a battle with a giant Canadian lynx, and the brown bears of Kodiak are notable for their short tempers, while even a moose is not averse to charging, if cornered. The introduction of reindeer into Alaska has lessened the game hunting by Indians and Eskimos in search of food, Instead COMBS IN CARPET SWEEPER KEEP BRUSHES CLEAN Brushes in a carpet now on the market automatically keep clean, sav- ing the user much unpleasant work and loss of sweeper time. This is accomplished by combs, so adjusted that they remove dirt from the bris- tles as they revolve and convey it to the sweeper pan, One comb swings in as the other swings out, the ac- tion clean the clean the For sweepers not already equipped Causing the combs to brushes and the brushes to combs. of being nomads, continually moving from place to place to follow the migrations of the game, the natives are settling down to the job of shepherding the vast flocks of reindeer, 1 Starting only a few years ago with 1,200 animals imported by the grovernment from Siberia, the herds are now counted in the hundreds of thou- sands, and a thriving meat-packing in- dustry is springing up. The reindeer also are displacing the dog teams. Their greater speed, and ability to dig out their food from beneath the snow, make them especially valuable. combs installed with with these cleaning units, sets of are furnished and little trouble. may be CORN HUSKS TO POLISH RUBBER SERVE AS EMERY husks, waste product, have been applied to va- Corn generally considered as a rious manufacturing processes as polish- ers for hard rubber. between two Cleaned and clamped iron disks, with an axle through the center, the butt ends are used to give a high luster to the material in much the same way as emery wheels are employed. Automobile and combs of hard wheels well as a number of other articles of common use, are often polished in this manner. steering rubber, as

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POPULAR MECHANICS 295 SPEECH IN EIGHT LANGUAGES AT SAME TIME BY RADIO With the aid of interpreters and a spe cial broadcasting installation, persons at tending a labor conference at Geneva were able to hear the same speech in as many as eight languages at one time. As the talker delivered his address, the inter- preters, sitting at microphones, translated his words into different tongues and re- layed them through an amplifying circuit to the hall, where the auditors were pro- ided with special listening equipment, so hat they could tune in on any translation desired. The interpreters talked in low tones so as not to disturb the speaker or nterfere with each other. Experiment re being m ile to record the speeches i] he various languages without the help of hortl and reporters. STEERING WHEEL TURNS LIGHTS FOR SAFER DRIVING Driving the automobile at night is made ater and easier with a pair of lights ad justed to turn as the steering wheel i turned so that the roadside is well illumi nated on either side and on turns. Being set below the reculat lights, the special Home Exercising Outfit, with Special Attachment to lamps do not shine into the eves of ap- Stretch and Strengthen the Neck Muscles srroachine drivers The ¢ ye operated > SS ee the sis gs Hy ie we : NECK EXERCISER FOR HOME USE ! vi t tl ain lights and hi HELPS PROMOTE HEALTH a special control button on the dash, Attached to the door frame, or other convenient location, an exerciser to strengthen the muscles of the neck has heen introduced It atfords healthful re reation, calculated to improve the circu lation and benefit the nerves, MICROPHONES IN JAIL ROOM TO TRAP PRISONERS Microphones and loud speakers have been used successfully in the Los Angele county jail in ob‘aining evidence against prisoners. Installed in the “shadow box,” the room where suspects are paraded un der powerful electric lights shining through a screen, thev give attornevs and deputies an opportunity to “listen in” on the prisoners’ talk Detectives are ; tioned in a room removed trom the Photograph and Drawing to Show How the Special Automobile Lights Swing with the Front Wheels shadow box

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296 POPULAR Model of the Diving Bell for Submarine Rescues, with Small Craft to Show Method of Connecting DIVING BELL FOR SUBMARINES TO AID IN RESCUES For rescuing men trapped in subma- rines, two eastern inventors have devised a diving bell that can be lowered to the sunken craft, screwed to a special porthole in the submarine and so afford a means of escape for the occupants. From six to ten men can be accommodated in the bell at one time. SCULPTOR WORKS SIX YEARS ON WAR MEMORIAL One of the most elaborate stone carv- ings in this country is under way on the Elks memorial building in Chicago, where a 170-foot panorama of War and Peace is | “ lat MECHANICS around the It is the work of Adolph A. Weinman, who spent nearly being chiseled as a border front of the structure. four years in preparing the plaster models and in making studies for the huge bas- reliefs. One-half of the work has just been completed after a vear of carving, and the other half will be finished in the summer of 1929. Scores of figures, each cut in great detail, appear in the designs. The panorama of War, already finished, depicts Satan and Gossip starting baseless rumors to incite a conflict. Greed clutches his money bags and seeks protection be- hind the throne, while the ruler signals his heralds to sound The dogs of war are unleashed and stalwart men march forth to battle. Scenes of carnage are depicted and finally Victory emerges in triumph to receive the ever- green sprig of immortality, offered by Truth. The panorama of Peace will be represented in symbolic tableaux. The work will cost approximately $120,000. the call to arms. IMPROVED NEON ARC LIGHT TO AID AVIATORS The brilliant red rays of neon-gas light that penetrate fog will be better adapted to use on airplane landing fields and other places, it is believed, through the introduc- tion of an improved tube for producing the light. By means of an additional elec- tric circuit, the through cathode or which the current into the tube, is heated, giving off electrons that cause the neon gas to glow and mak- electrode, passes — ing it unnecessary to have such high voltages as are required in the older tubes. In the opin- ion of Dr. J. D. Forney, ‘who worked with Dr. Clifton F. Found in pre- paring the new tube, the light should be useful in photography when com- bined with the mercury- vapor light. @ Thirteen species of rat- Close View of One of the Stone Figures in the Panorama of War on the Elks Memorial; a Pageant of Peace Is Being Carved Opposite known in the United States. tlesnakes are

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a MAKE THIS EFFECTIVE DRUM SF By H-C-MS Kay , ins interest in speakers of the tension- diaphragm because of the remarkable fidelity with which the entire range of sound is reproduced. One type is growing of the principal objections is the awkward size and shape, which make it rather diffi- cult to house the instrument attractively if the console is not large enough to take the diaphragm. The author, desiring to experiment with a loud speaker of this type, hit upon the tov-drum and cage- stand idea described in this article as a novel solution of the problem. The use of cloth for the diaphragms in the this type has several dis- advantages and the skin head of the drum suggested a good substitute. A drum of rood size can be pur- speakers of chased at a reason- able price. It should have at least one real skin head and should be fitted with metal strainer AKER bars instead of the leather type © that equal tension mav be maint ed i ad dition to the drum and birdcage stand, the only other materials necessary are: a piece of thin wood about . in, thick by 3 in. wide and long enough to extend across one face of the drum: a heavy duty cone-speaker unit imilar to the tvpes shown on page 298, and two heavy conical meta disks th a hucl and readed bushing Taking the Drum Apart; the Apex Shields and Pict Cords Are Shown at the Right ragm Metal d sks ( ] uc k nd | Is! iy are Oo iva lable Tot! Dp « ike1 of this ar the 1 rust oO ¢ S fu ed th the cr ¢ peaker unit 1s t readed at the ‘ endfora ocking nut and either screwed to ¢ bt it init ‘ d op ed rit« 1 mali ole t | ¢ rating member : here it held 1

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298 POPULAR MECHANICS will drain off through this hole, leaving the upright edges of the head dry. The wet skin is mopped with a towel or other absorbent cloth until the surface is dry, leaving the head soft and pliable and con- siderably stretched, The paper head is placed over the shell of the drum, and the thrust rod of the speaker unit, with the chuck and bushing disk slipped back toward the unit end, is ready for the paper diaphragm. In some cases the metal disk with the chuck is de signed so that it may be mounted di rectly on the diaphragm. In either case the conical metal disk for the paper diaphragm must be placed so that the holding surface is toward the apex, as shown in the top photo and _ sectional diagram on page 299, The thrust rod is li 1 slipped through this disk on the paper diaphragm, and you means of a setscrew. The photo on page 297 shows the necessary materials assembled before construction 1s started, the first step being to dis- mount the drum The te nsion, or strainer, bars and the heads are then = are re ady to place the skin head in position on the shell of the drum. The centers of the reads, with the metal disk in po ition on the = skin head, are pushed together until the rod protrudes through the front a loosened and _ re- 3 = ¢. = disk: a small hexa- | gon nut is then movedandthe hoops lifted off. Us STRIP _OF WOOD FOR y SUPPORTING THE UNIT - ually drums of the less expensive type have one skin and one fiber, or parchment-paper, head. A small hole is punched in the exact center of the paper head, using great care that the hole is properly located and just large enough to permit the thrust rod of the speaker unit to pass through it. Next the skin head is placed over a large pan, with the rim up as shown in the bottom photo on this page. A dish- pan was used by the author and happened to be just the right size for the purpose. Now pour \% pt. or so of warm water into the top of the skin head and let it stand until the head is thoroughly soaked, which will require only a few moments. Then, with a sharp awl, a hole is pierced in the exact center of the head. The water ke Top, Drum Dismounted Ready for Preparing the Heads; Center, Two Suitable Standard Cone Units and Detail of the Wooden Supporting Strip; Bottom, Pouring Warm Water into the Head, to Soften the Skin

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POPULAR MECHANICS P ~ screwed in place on the end of the rod, or apex, and the two heads will now retain their positions upon the drum shell. If trouble is encountered in coupling the heads on’the rod, loosen the chuck bush- ing on the end back of the paper dia- phragm and readjust it so that the apex nut may be screwed in position. Any extra tension required may then be ob- tained by screwing the nut down. The next step is to apply the hoops and strainer bars. When this is done, the drum will appear as shown in the bottom photo, This completes the con- struction of the speaker itself; the strain- er bars are tightened barely enough to hold them in place and the drum is then set away in a dry place for 24 hours. At the end of this time, the skin head should be thoroughly tight and dry. If the work has been properly done, rubbing the finger over the head will produce a loud rasping sound, and PAPER HEAD~, both heads will be un- e oy -_ der tension owing to \ screws as shown in the the drying of the skin. SKIN HEAD > 4 sectional diagram. The The wood piece is proper location of the now cut and the ends METAL DISKS~ oe _ —_ speaker unit on the rounded so that it will APEX ~~~ is wood stri p is impor just fit in the hoop on tant; therefore, see the side of the drum we Ae ee { t h at the unit is so bearing the paper j placed that the thrust head. The cone- speaker unit is rod may be iastened to ! \ the vibrating element / Si?) mounted upon this ak 4 q without subjecting the strip with wood \ rod to any side strain UNIT / The wood strip STRIP OF woop! screwed in position on SECTIONAL VIEW the drum shell as shown 1 +} e photo on page 300. and the thrust rod ecured to the unit by means of the setscrew. If the thrust rod is permanently fastened to the speaker unit, it will, of course, be necessary to push it through the diaphragms and _ s¢ cure it at the apex after the board is position, the actual method varving ac cording to the tvpe of metal disks used and the design of the speaker unit. A pair of picture cords and hangers of the rosette tvpe serve to support the drum S aAKeT ON he birdcage stat f S nd Top, Assembling the Speaker and Connecting the peaker 1 the birdcage sta d If a sta - Heads; Center, Sectional Diagram Showing the ot the tvpe shown is not available, a meta Method of Connecting the Heads and Mounting the EES ee oe ees : Cone-Speaker Unit; Bottom, Stretching the Heads bracket projecting from the wall at any

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300 POPULAR Rear View of Completed Drum Speaker Showing the Wooden Strip Supporting the Speaker Unit convenient point will answer as well. The diaphragm may be decorated’ with water colors if desired. Do not use heavy- bodied pigments for this purpose, as they might interfere with the acoustic proper- ties of the diaphragm, particularly if they start to peel. Transfers or decalcomania also may be used to good advantage for decorative effects. Speakers of this type are supersensitive to vibrations owing to the fact that the diaphragm is under stress at all times; see that there is no loss of energy due to a whipping or side motion of the thrust rod. The speaker units suggested operate efficiently with any B-voltage either with or without power tubes. @ Popular Mechanics’ radio department offers its information service free to all readers of the magazine. MECHANICS Good Tuning Devices Important The tuning devices in a radio receiver handle the high-frequency energy which is elusive compared with the ,audio, or low-frequency, energy following the de- tector. These devices include antenna coils, r.f. transformers, fixed and variable condensers and tickler or feedback coils. These parts must be selected with great care and only standard tested devices used, as nothing but the best materials and workmanship will produce the results now demanded by the critical broadcast lis- tener. Good low-loss variable condensers should be strongly built and easily ad- justed; fixed condensers of the mica-in- sulated type in molded bakelite are now available and are dependable. When wir- ing the r.f. end of the receiver, space the coils 4 or 5 in. apart, if possible, and keep the fields at right angles. Shielding is ad- visable, and, if convenient, each section should be entirely inclosed. If this is impossible, owing to the nature of the assembly, use shielding plates mounted between the units. Excellent aluminum shields of the single-panel and knock- down box type are now available in a va- riety of sizes. It should be remembered also that it is good practice to connect the stationary plates of the variable con- densers to the grid circuit of the tube, to avoid hand-capacity effects. Keep all grid and plate leads as short as possible and well separated; do not parellel these leads and keep all wiring carrying r.f. cur rent away from the filament wiring. Charging Batteries from D. C. Supply The simple arrangement shown in the sketch provides a method of charging storage batteries from a 110-volt d.c. line. The input is controlled by an ordinary wee] “GRIF ‘nit mounted CURRENT ) : NO-V D.C. 3 / in a porcelain- base lamp socket and the charging rate is about 7 amp. The heater unit is connected in series with the BATTERY

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POPULAR positive line, which may be identified by holding the terminals about 4% in. apart na glass of water in which a pinch of salt has been dissolved, the terminal caus solution A device of this kind can not be used with a.c. current. A cheap immeter of the auto type should be placed n series with one side of the checking the charging rate. unit ng the least disturbance in the being positive. line for The heatet should be mounted on an asbestos pad and in a location where the heat gen erated will do no harm. Safety Stop for Screw-In Rheostat Rheostats of the screw-in, or carbon, tvpe should be provided with a safety stop used tubes of the 199-type They are efficient but when with the 3-volt tubes some means of know- when with very used ing just how far to them in or out to obtain the required voltage, is nec- essary. A machine screw, about % in. long, mounted on the panel directly over the rheostat knob and just high enough so that the knob will clear the nuts turned in, provides an adjustable mount- ing for a long soldering lug which acts as screw when a safety stop. The machine screw is se- cured against the panel with one nut, and the soldering lug is held in the desired po- two additional nuts. The tube voltage is found by means of sition by correct means of a volt- meter held across the filament ter- minals of the tube socket; the lug is then the screw to stop the knob at this adjusted on RHEOSTAT position and the (TURN IN AND OUT) Bo my VARIETY nuts are locked. Reducing Power-Line Pick-Ups Broad tuning is frequently caused by power-line pick-up when a receiver is operated with a socket-power device. It may be caused by the power line acting as an aerial and ground system, owing to the manner in which the plug is placed in the wall socket. Reversing the plug will usu- ally eliminate the trouble. MECHANICS 301 Combination Test Set for Direct and Alternating Cur- rent Tubes with Adapters and Other Accessories Combination A. C. and D. C. Test Set he popularity of sets using a.c. tubes has brought many new problems to the experimenter and radio-service man. The new set-testing outfit shown was specially designed to make simple and highly effi cient tests possible where either a.c. o1 d.c. is employed. In operating the com bination test set, a tube is removed from the receiver and the plug inserted into that socket. Adapters of various types are sup plied so that sets emploving any of the tubes or tubes of the old tested for certain tests standard tvpe Provision is also made on the UY Binding posts are sup- mav be five prong base combination plied SO that tubes having indirectly heated filaments with terminals at the top may also be handled. The meter at uppet left is an 0 to 150-volt a.c. instrument with binding posts for checking line voltage The upper right-hand instrument is an a.c. voltmeter with a 3 and ] volt Various a.c. range ol had on the Plainly marked and easily operated push buttons . so that readings mav be filaments now in use are supplied for connecting either of these leads from the plug, so that readings of true filament low readings to the filament voltage mav be taken rapidly.

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Facts and Fads for Radio Fans Upper Left, Photo-Radio Receiver Recording in New York a Signed Let ter Transmitted from Paris; Above, a New Device, Recently Tried at the New York Insti tute for the Deaf and Di », Enabled the Stu lents to Hear an Entire Radio Program for the First Time; S. A. Dic erson Is Shown Demon- Strating the Device Above, the First Telephone and the Latest Loud Speaker Utilized to Demonstrate the Development of Electrical Science at the New York Meeting of the Engineers’ Society; Sergius P. Grace Is Speaking through a Model of Bell's | First Telephone, His Voice Being Amplified 100,000 Times by the Giant Speaker; Right, Navy-De- partment Operator Receiving Radio Messages at a Speed of Seventy- Five Words per Minute, the Re- corder at*the Right Registering the Message as a Wavy Line 302

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Chive ways to ELECTRIFY YOUR SET ANUFACTURERS of tubes, trans- i formers, cabled harness and sockets have pooled their efforts to simplify the changes necessary in standard battery-op- erated sets to adapt them for the use of the new a.c. tubes. The introduction of these tubes had a rather disturbing effect at first, due to a lack of understanding on the part of the public, who, of course, did not take kindly to the idea of junking per- fectly good sets in order to use the new tubes. When it is understood that the change involves the installation of the proper sockets, and the rewiring of the filament circuit only, and that suitable de- vices for the purpose are now available, the job loses its formidable aspect. As there are a number of methods now in use and several VUES TUEDUDEDVULOVOVENTOVELOOOG PEWEOUDEOTELUODODEDUVULGRTTUVLTCOUUDIVODG:TOVLEEEI@OODADTOOODALORODOORDNDEOBY ERD EY familiar with the Arc- turus type emploved in the All-Electric- Five receiver described in the April, 1928, issue, hence this will not be discussed now. The or 326 and 327-types are of two varieties, Our readers are ) RCA and Cunningham 226 and 227 one having a directly heated filament and the other containing a separate heater ele- ment which is not directly connected into the receiver circuit. The 226-type employs a standard four-prong base, while the de tector 227-tvpe, with the separate heater, | the filament-heater the top of from the sides of a special base. When las five other brought taken prongs in base. In types, wires out at are the tube or are using raw new types of a.c. tubes on the market, it is not possible to go into detail as to the merits of each. The a.c. current in a sen sitive receiver, it is necessary to keep these wires as far as possible from the reader should un- derstand that a change to a.c. tubes does not necessarily GROUND and IF DESIRED grid and plate leads, the filament should be twisted lampcords and wires sha c. TUBES add to the efficiency " or similar cable of of his set, and that 1ST 2 ND sufficient current- RF 201A RF 201A these tubes have been developed sim- ply as a cohvenient 3 method of doing f carrying capacity away with the stor- age battery and the charger. D.c. TUBES im §) ) for the tubes. if 4 Ordinary rheo- stats are not used in the filament cir- cuit. Ifa control is desired, there is an

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304 POPULAR MECHANICS special socket adapters which insulate the yoy> tubes from the original filament terminals le in the sockets and provide new filament or ‘pe heater leads. Figs. 2,3 and 4 show one type of adapter harness and special step-down trans- ? former, making possible the conversion of by practically any battery-operated set with- o out changing any of the wires in the set e itself. The d.c, tubes are simply removed ec | from the set, the A and C-batteries discon- , nected and the th adapters supplied be with the harness in- th serted in the tube hi sockets, as shown th in Fig. 3. The ends ry of the harness are ty labeled for the fo proper terminals on the step-down 7 automatic device transformer, as ct for the purpose of shown in the dia- au protecting the tube, gram, and are con- W or a rheostat of nected accordingly. €] proper type may be Since the A and C- n cut into the 110- batteries are discon- tr volt a.c. supply line nected, the A-bat- ti which also contains tery posts on the a power switch. In set remain unused, 9 order that the 110- volt current may be cut to the correct c- BIAS 7% FOR327- FOR 371 ] values, a step-down REGULATOR 110 vours } TYPE TUBE transformer is used, The 226 or amplifier tubes require 1% volts, while the detector or 227-type must be supplied with 21% volts. The positive FILAMENT y ; ee. REGULATOR C-battery connections and the negative- 1.5-VOLTS POWER TUBE ; . . ‘ yb C- BIAS B go to the grid-return lead instead of ‘ FOR 326 to the filament circuit, as in d.c. receivers. The comparative circuits, shown in heavy lines in Fig. 1, indicate where the filament wiring differs. Note that a .5- mid. by-pass condenser is used to prevent a short circuit that might result from the grounding of the lighting system. The filament connection to the 226-type tubes is provided by a center-tapped resistance obtainable from any dealer in radio sup- plies; this is connected as shown in the diagram. A slight hum is usually present in a.c. receivers but is not audible when a station is tuned in, These mechanical and electrical differ- ences in receivers originally designed for d.c. tubes are provided for by means of The C-negative terminals or binding posts are connected to the C-positive binding

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POPULAR posts with a short piece of wire, to com- plete the circuit, and the set is ready to ne ) rate without any batteries whatever, ii € B-eliminator is used. The variable re- stance or C-bias regulator, shown in Fig. is connected in series with the grid lead. adjusting this resistance, the C-bias oltage applied to these tubes may be ept desired value. ion of the adapter harness and that for le power tu DV at any The detector ect be are separate units, because be no electrical them. here should connection between The power-tube part of he harness has small container unit a using the resistor to bias the power tube the hese harnesses are supplied in different it provides necessary C-voltage using any standard filament trans- standard B-eliminator. 6 and Aly MECHANICS strated a combination A, B 1ST AF. STA — and ©-converter, whicl furnished : either in kit form or a mounted in an at- 0-500,000 OHM tractive teel con- +POWER | LAST RF. STAGE ‘4 eT reac to onp- ~ 24 Vv ‘ : Se. SOCKET COLORS ON CABLE - . GREEN -DETECTOR =p) ~ —_ ORANGE - POWER 4 oro} FL —~ = RED-RF AND IST.AF 24 5V © Ly POO SMV 1y Y, A (~ \ 2° 4o0000"'2 iW) - _ EG. SOs U = BLACK WANS b rowan — AMP. | Y Ww . PENDANT OR VEG GREEN [& © SIMILAR SWITCH : covor cone VOLUME- CONTROL ; COLO SUGGESTIONS OR USE SET SWITCH '" FoR CABLE Fig. 7. A C-vi ¢ hed in t , with the D ¢ \t 1 terminate n t { ted if I: a 5 i e Mume control, the the diagram (Fig. ( ee a *ram ot the p lf erminal connections ire also s} wn In Fig 8 is us offers the quickest c (7) tion, the entire outt ple té k iT l ( 1din : pis gy { s | there erate The 226 and 227-tvpe tubes pre new connectiotr to . 2 P ” 1; its base t viously mentioned, as well as the 171 has on its base two pow er used shown, and a model for use with \rcturus tubes. Tl B-pow er unit ] 40) at 180 volts and em- 11° mil ivers rvs a full ive I t-tvpe rect e1 tube | the cket indicated in 1S ve ) fut Ci ert oO ib] ’ e plug i ce to I le i uc est n ’ , need e r the } at the 1 ( u ‘ ] ' ] 11ecd \ )) AD inge to a. e1 Col , 1 Col r the t i are ya ) be made ea tub ecIAa hiament of

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306 POPULAR MECHANICS HARNESS 7 (EAD yy AO kL > f rye ge ue ye | SPADE! f TAPS a Oe ee a : — au, HARNESS AC.FILAMENT SUPPLY | B- SUPPLY , TRANSFORMER _ fae YELLOW tae ° NOTE -- -9 V WHEN UxX412 A USED AS POWER TUBE SPE AKER ; ar) -* ry eS Ps xe eo Fal on ® Ry °° & SPK. | o x” © . RECEIVING-SET NOTE +135 V. WHEN 74 | UX-112A USED AS -7 TERMINALS OR eRe CABLE LEADS AC. ADAPTER HARNES heater connectors, as pointed out in Fig. Sg Connecting spades are arranged on the harness and are slipped over the ter- minals as indicated. The heater extension connections coming from the cable are twisted into pairs, and no attention what- ever is given to polarity connections. The special tubes employed all require the same heater voltage. The detector tube is plainly marked and should, of course, go in the detector socket of the set. The amplifier tubes all have the same charac teristics and no dis- So oe ree a —_ AF AF.| DET. )RF3 REZ RFI UX-I71 UX-226 UY-227(UKX-226 UK226 UX-226 ILLUSTRATION SHOWS SIXx- «VOLUME TUBE HARNESS. WIRING THE (O)) contro (9 SAME FOR FIVE TUBE HARNESS ‘“— ~ | entirely by the light-socket switch. Wit! this apparatus, it 1s possible to change the standard five or six-tube set in less than five minutes Fig. 10 shows an adapter harness and standard filament-heating transformer similar to others previously described foi adapting storage-batterv-operated sets to use the type 226 and 227-tubes; but in this case the C-power supply is obtained with the usual C-battery. The device shown in Fig, 11 goes a step farther than any of the other adapters. Complete a.c. harness, A and B-power supply and power amplification for a UX- 210 or CX-310 tube are provided. Antenna Protects Building A properly installed antenna should al- ways be provided with a lightning arrester connected between tinction is made for TO E219 IN POWERIZER) their positions. The s a Oo > ; adapters are plugged into the set sockets and the tubes inserted; the Bh-eliminator, if one is used, is plugged ANY SET directly into the re- ceptacle at the top of the transformer unit, and the power i) is then controlled it and ground. De- \ vices of this type \ approved by the in- } surance under- writers are not ex- pensive and may be obtained from any dealer in radio sup- plies. The antenna, so protected, not = only prevents dam- age to the set but also provides Sf d Sl

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POPULAR MECHANICS 307 otection for the building. It is prefer- ile that the ground lead from the light- ng arrester be kept outside, although is is not insisted upon. A lightning ar- ster is safer than a switch, since the lat- is manually operated and the owner iv forget to throw it to the ground when e set is not in use. )id Auto Generator as Battery Charger \ very good battery charger can be ide for about $2 from parts that may be tained from an auto junk dealer. Sev- ral weeks ago I made up my mind to do ay with the trouble, cost and enience of taking the battery to the serv- e station, and this is how I The %4-hp. electric motor used about incon- went about e house for general purposes caught my ve, suggesting that it might be employed or charging purposes in connection with A trip to the local dealer in junked cars resulted in the pur- chase ot in old auto generator. a generator, with a breaker box on it, and an ammeter for $1.50. Upon A NEGATIVE inv return home, I BREAKER BOX ' POSITIVE POST CONNECTION made a wooden pul- ley, 3 in. in diameter which hap pened to be the correct size for the speed of the generator. The latter was at one end of a 3-ft. plank, about l ft. wide, as shown, and the GENERATOR motor on The motor was then belted and the battery con- nected to the terminals indicated, with the ammeter in side of the line. The outfit worked fine with the exception that the charging rate was a little high, accord ing to the ammeter, but this was adjusted by means of a setscrew directly beneath the breaker The ‘alteration in the rate may also be obtained by changing the size of the wooden pulley to regulate the speed. The breaker box acts as a safety device and the installation is extremely simple—E. D. Fahling, Tama, Iowa. the other end. 7 to the generator one box. Self-Winding Reel for Loud Speaker A self-wind- ing reel with 25 ft. is now availa ble for quickly placing the loud speaker in an adjoin ing room, or changing the speaker to va rious ot cord loca- around same The device is fin- ished in nickel or brown ma tions the room, be mounted ac any convenient point on or near the set Lengths of cord may be added by means of small cord-tip couplers, hogany enamel and may New Coil Has Twin Rotors The twin-rotor coil shown in the illus- tration is builders and provides a means of varying the cou- now available for set pling between the primary and secondary to suit the conditions peculiar to any lo cation. As three-circuit tuners have a pri- mary, secondary and tickler winding, and in the usual tuner of the three-circuit type, a the primary and secondary windings are stationary, the fixed coupling is deter- mined by the distance between these coils must choose 17 tight coupling that will The set builder between a ] proauce good sig ~ 1 nal volume but poor selectivity, or place the coils far apart and get good selectivity volume The nearness stations will. of at the sacrifice of if powerful broadcasting course, determine the coupling. The problem ts solved by the proper degree ol double - rotor coil,as the pri mary is wound on one of the rotors and the coupling may be varied as desired,

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308 POPULAR

Radio Tables for the New Electric Sets, Showing Two Ar- rangements Tables for Electric Sets Electrically operated radio sets require little room, and the attractive tables shown in the photo are small enough to fit almost anywhere, yet sufficiently large to accom- modate not only the complete radio set but a row of books as well, if desired. Two suggestions for the installation are illus- trated. The manufacturer also supplies a similar table provided with two book shelves below. Electrolytic B-Eliminator Kink When building electrolytic B-elimina- tors of the type described in the Febru- ary, 1927, issue of Popular Mechanics, difficulty is often experienced in prevent- ing overheating during the cell-forming process. It is almost impossible to find a rubber tape that will cling to the flat: sur- face of the wide aluminum electrodes, as the liquid seems to creep up under the insulation, causing surface sparking, heat- ing of the cells and pitting of the elec- trodes. The writer used several kinds of insulating preparations with varying suc- cess, but finally found a simple method that proved highly satisfactory. The de- tails of this are shown in the sketch. Pur- chase some mica of the kind used in heat- ing stoves and strip off layers until thin sheets are obtained; the thinner the sheets the better. Cut the upper part of all the aluminum plates to a width of in., that / I > /2 MECHANICS is, all the portion to be insulated, and also both lead plates of the rectifier cells Round the edges with a clean file, so that the mica will fit tightly against the metal, over the edges, without cracking. Coat each portion to be insulated with a good grade of insulating varnish, obtainable from any electrical-supply house. Cut a piece of paper long enough to go around this coated portion and slightly overlap, and use it as a pattern for cutting the mica to the correct size. When putting on the mica, use a narrow piece of heavy paper, about the thickness of a_ postal card, and lay this over the mica when bending it around the plate so as not to break the edges. Hold the mica in posi- tion and have someone tie it on the elec- trode in several places. When all elec- trodes are prepared in this manner, wrap heavy thread tightly over the mica, re- moving the temporary cords as you pro- ceed with the winding, and tie both ends of the thread securely. Next coat the en- tire wrapped portion with the insulating varnish. Two or three coats should be applied, allowing each coat to dry thor- oughly. The lead electrodes in the tank and filter condensers need no mica insu- lation and three or four coats of the in- sulating varnish will protect them suffi- ciently. Assemble the electrodes in their respective ‘: “<-=3 P . there ---+fe CUT cells, where I: our. they can now 5 be formed ex- ~~ ROUND A actly as shown eal TA te in the blue- | yayx ann print diagram | FILTER COND. No. 1177. No | further trou- ble from over- heating will be experi- enced. The writer has used this eliminator al- most every night for four or five hours during the past three months with very satisfactory results. The electrolyte has dropped only Mz in. during this time and no oil of any kind was used on top of the solution. The cells are as cool after four or five hours’ service as when first turned on.—Theodore H. Hanson, Clinton, Iowa.

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acll® kxperisy Soldering Lead to Lead It is not an easy matter to solder lead but it can be done and such con- nections are sometimes advisable on stor- age batteries or other radio \ good hot iron, well tinned, and some regular soldering acid are necessary. First clean the lead parts thoroughly by scrap- ing. Place a small amount of the acid on the surface to be soldered and tin piece separately by rubbing the hot iron, with solder, over the cleaned surface. Now place the pieces together and the taking great that direct contact with thé iron is on the solder and not on the lead. to lead, accessories. each flow solder in, care The shade of difference between the melting points of solder and lead makes this a rather ticklish operation, but with a little practice, good solid con- made. Where two flat pieces are to be joined, or a small flat piece to a heavier one, a small hole may be drilled through the thinner flat piece, and, after the surfaces to be joined are tinned, the point of the iron is applied through the hole. Turning the iron care- fully in the hole and applying nections can be solder so that it will flow into the joint will pro- duce an excellent but tice is indispensable. Soldered storage-battery nicely, connection, prac- connec- tions on terminals will hold but must be protected with vaseline or grease to prevent the battery acid from attacking the tin in the solder. If it is lead wire to a lead and the solder a tin the necessary ‘to terminal, first ‘hed ied : wire and then join them by holding the -Harry Saine engineer, Station KQW, San Jose, Calii hot iron on the wire Test Points from Phone Plugs Old shown in telephone plugs used a the and testing points for checking circuits may be excellent No but it 1 11 sketch make alteration in the plugs is needed, a good idea to file or grind the ball ends to a blunt One long flexible lead point. made from a length of telephone cord o1 similar insulated wire, is required for each plug. An old receiver cord with the oute cotton or silk covering removed will serve excellently. Since the long brass sleeve in the plug is not connected in the circuit it does not matter if it touches anv instru ment while testing, but, if desired, it may be covered es with rubber = tubing. The ATTERY , tampon Sern piorg ge TELEPHONE nected to the PLUGS : FDS _— insulated pol \ tion ot the that ter minates in the plug bare pointed end. The BRASS ENDS usual circuit A FILED TO POINTS for continuity tests is shown in the sketch, and consists and either aclamp or mete tor the nuous circuit indicato1 H R. Wallin, radio operator, Brooklyn, N. Y ot a battery, conti 9

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310 POPULAR MECHANICS Building a Telescope Antenna All amateurs working with short-wave transmitters have encountered difficulty in obtaining maximum radiation when shift- ee ing from one ; short-wave band reegeeitiligtt to another. If the PORCELAIN ; ( ae. ae antenna 1s correct 1 t ates for the &80-meter a | band, it does not | UPPER . ' "TUBE ---> | radiate properly ‘ on the 20 and 40- ! i) 7 MAST—--f--=F meter bands. The on writer has worked COLLAR AND out the telescope THUMB- | . : SCREW -- antenna shown in | the sketch and LARGER i found it a better (ones Tae i) method than cut- I ting off, or splic- Th | ing, a lead-in ac- ROOF ~ i" H : ; STOTT ,«=CiC coding to usual HE practice. The an- tenna is placed di- rectly above the set, with the lower end threaded and screwed to the top of the roof insulator. This lower section consists of 8 ft. of %- in. brass tubing. The upper part of the rig is made up of two 10-ft. sections of \4-in. brass tubing, held together by a threaded coupling. This part is held ver- tical by means of porcelain stand-off in- sulators mounted on one side of a strongly guyved 2 by 2-in. pine mast. A_ brass collar, turned in a lathe and tapped for a thumbscrew at one side, is slipped over the lower section near the top, a hole be- ing drilled there to allow the thumbscrew to clamp the inside tube. When testing the installation on the various wave bands and finding the radiation about half what I think it should be, I slide the aerial up or down about 6 in. until the correct point for best results is located—Harold S. Sykes, operator, Station KGAR, Tucson, Arizona. ROOF INSULATOR Prolonging Dry-Cell Life Strictly speaking, there is no such thing as a “dry” cell, for the content is actu- ally a moist paste which, when it be- comes perfectly dry, causes the battery to become useless. In order to prevent undue drying out, such batteries should never be kept where there is too much heat and, by the same token, extreme cold may have a similar effect. Some radio ama- teurs make it a practice to coat all bat- teries with paraffin or wax to prevent ac- cess of air and thus delay drying out, while some of the better makes of dry B-bat- teries are entirely impregnated in wax for the same reason. Usually these batteries will last from two to three times as long as batteries which have not been treated. Dry cells should also be kept in an up- right position at all times and the ordinary cell used for doorbell ringing will last much longer, if installed in this manner. - The same thing holds true of dry B and C-batteries, which should be so placed that the cells, inside the casing, are ver- tical and not on their sides. Proper treat- ment of batteries will usually double their lives—Wm. F. Crosby, engineer, Wire- less Radio Corp., Brooklyn, N. Y. Detector Circuit without B-Battery The accompanying diagram shows a new detector circuit emploving a two- element tube, which may be any ordinary three-element type, such as the C-301A, with the plate and grid short-circuited. This circuit is unlike the DeForest and Fleming systems of early design and is of additional interest, owing to the fact that no B-battery Agra : is employed ; in fact, the plate is given a slight nega- tive potential by return to the negative side of the A- battery. It will be noted that the filament current flows through the inductances and that the emission of electrons from the 4la- ment and their flow to the plate are di- rectly controlled by the rf. fluctuations present at the high-potential end of the pair of tuning coils. Two coils are neces- sary to prevent the direct short-circuiting of the tuning condenser by the filament. The antenna coupler may be any standard type with the secondary rewound to 100 turns; the second coil in the filament cir- 100 (TURNS + GND. © VOLTS ee een RE HEIN ta cil Mitt 9 As

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POPULAR 100 turns. For those who vind their own coils, the following data useful: A .00035-mfd. variable condenser is employed in the circuit given d the coils are wound on a tube form, in, in diameter, the wire being No. 24 Lec. If the condenser is .0005 mfd., use the same-size wire and tube and wind the coils 77 turns each. The primary il at left depends on the length of aerial ised; try 15 or 20 turns for this coil on the same-size form and either add or de- turns until the set tunes sharply. (his system of detection gives excellent results when employed with any standard and prevents tube vhich so often occurs with the grid-con- lenser and gridleak method. The quality obtained is excellent and com- pares favorably with crystal detection.— L. J. Lesh, consulting engineer, Chicago, ° . 1 ‘ult 18 also may be luct radio. set blocking of signal An Inexpensive Push-Pull Amplifier A good push-pull amplifier may be built at a very low cost, without the usual cen ter-tapped transformers ordinarily re- quired for this type. audio transformer of good make and use it as the input-transformer to the push-pull stage. \ 500.000-ohm shunted across the secondary of the trans- The negative of the Select an potentiometer is former as shown, C-batter) of the potentiometer to provide the neg ative bias for the grids of the push-puil The output circuit is composed of two Amerchokes, or autoformers, and two .5-mid. condensers, feed the loud speaker, Alternating current is used to light the filaments by means of any standard filament-heating transformer is connected to the center tap tubes. which MECHANICS 311 Handy Radio-Program Index Radio listeners who are in the habit of selecting their programs in advance will find the idea illustrated in the sketch very DATA WRITTEN ON LONG STRIP OF PAPER . FILM '_- ie SPOOLS AUTOGRAPHIC CAMERA -~ Left, Data Strip Wound on Spool Ready for Inserting in the Camera; Right, Strip in Position data An most No change in it is neces- convenient tor keeping such autographic available in homes, sary. camera, is used. A strip of white paper, several feet long, is cut to the is wound on a width of the film and spare spool. The pro written in with and reading has been completed, the grams selected are typed or pencil on thi strip of paper along the date, time, station dial When the list strip is rolled on the film spool, inserted in the camera and turned to position as shown. Any of the data then be read through the slot by merely turning the film spool—H. R. Wallin, ra- dio operator, Brooklyn, N. Y. inscribed may Reducing Local Interference found that much local interference can be reduced or eliminated The writer has and there is no noticeable hum. The original amplifier AF TRANS owe built by the writer i fe 500.000 Y OHM POT emploved two UX- bei 171 tubes. At pres- = ent, an amplifier of 7" I, this type, having two 50-watt tubes and feeding six C-BAT, 4 + 135-V. li|! large exponential =F horns, is being used ‘ . his . , -L- ; e sctar ox, for puplic -address work and is satistactory in every respect.—M. J. Weiner, chief engineer, Station WODA, Paterson, N. J. SUPPLY Circuit Diagram for Simple Push-Pull Amplifier by the simple expedient of discon — necting the ground | lead from the set 3|| scion and shifting the aerial to the ground post The coils in the set will usually LOUD SPEAKER sue. pick up enough en ergy to bring in the +180 — : signals, making re ception possible un der conditions that are often regarded as hopeless C. R. Yarger, chiet Station KINF, engineer, Shenandoah, Iowa.

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Handy Radio-Testing Points By combining two sewing needles, two small pin vises, one pair of headphones and a small flashlight battery, as shown in the sketch, a very handy outfit for test- BATTERY —--HOLES FOR CORD TIPS ~~ SEWING NEEDLES Poa sly Testing Instrument Assembled from Needles, Pin Vises and a Headset, Showing Connections ing open circuits in radio apparatus may be had at little expense. The battery is fastened to the headband with tape and is connected in series with one side of the phones. The pin vises should be pro- vided with insulated handles, and small holes are drilled in the side of each metal shank to take the cord tips. When drill- ing these holes, first measure the latter and drill the holes slightly smaller, say, 001 in., to provide a friction fit. With ordinary needles in the pin vises, coils wound with fine wire may be penetrated and explored for open circuits in trans- formers and for other tests. A_ partic- ular advantage of this combination is that nothing is destroved in making the instru- ment.—J, McIntyre, Hartford, Conn. C-Voltage Depends on B-Voltage If B-batteries are used to supply the plate current for a receiver, the voltage should be watched and the batteries dis- carded when each 45-volt block runs down to about 34 volts, or when that of each 221%4-volt block drops to about 17. It is necessary to provide a proper rela- tion between the C-voltage and B, or plate, voltage. It is generally known that while B-batteries run down in use, the C-bat- tery loses practically no voltage in its en- POPULAR MECHANICS tire life. This means that when the B- batteries are new, the proper C-battery is being used for best results, but just as soon as the B-voltage begins to drop, the C-voltage is greater than is needed. For example, if a power tube of the CX-112A type is operated with new B-batteries sup- plying a total of 135 volts and used with the recommended 9-volt C-bias, the cur- rent drawn by the tube is about 6 milliamp. If the B-batteries are allowed to run down to 34 volts per 45-volt unit, or a total of 102 volts, the current drain with an ap- plied voltage of 102 volts in the plate cir- cuit, and a negative grid bias of 9 volts, will be approximately 1 milliamp. Under such conditions, the tube will not operate at proper efficiency, but if the C-voltage is reduced in proportion, the amplifying efficiency of the tube can be maintained at a high level in spite of the lowered plate voltage. In the example mentioned, a re- duction of C-voltage to 6 volts instead of 9 will cause a current flow of about 5 mil- liamp., at a plate voltage of 102. The same applies to the first audio stage; for in- stance, if 90 volts of B-battery is used and drops to, say, 68 volts, reduce the C-bat- tery from 414 to 3 volts for a 301A-tube. A Practical Cone-Speaker Kink There are few if any cone-type speakers which do not at one time or another de- velop a singing tone, owing, it has been found, simply to vibration of the driving pin. This interferes greatly with the dia- phragm. The drawback may easily be overcome by the simple method shown in the sketch. Obtain some electricians’ tape, wind up enough to make a roll about 1% in. in diameter and leave an end by which to fasten it to the pin, as shown, with- out touching This light weight the surface of the cone. will change the vibration period, and the general tone of the speaker over all fre- quencies will be appreciably improved.— L. H. Georger, Buffalo, N. Y.

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by

" _ A hic

boys of a generation ago believed that the most glorious career lay in be

ul AMATEUI tak 2, ANIC MECHA 1S. PUT Plane for “Lindy Junior” UII

omething should be constructive that every boy encouraged in

coming a fireman or a circus acrobat, but that aviation is still in its pin feathers now, with such an idol as Lindbergh be- and that there is a promising future for all fore them, they have turned to aviation who take up flying as a career—particu with even greater enthusiasm. Here is larlv those of mechanical turn of mind TEMP. GAUGE) bps a 2 ALTIMETER - Ps e+ Gaeee __ AIR ; og Ss} tpt gi, * ° 773 3 F : gs 2 Se, e .\ < P ; {z= eke a ‘compass | ‘ THROTTLE | jos. fe PULLEY | Open? yee TACHOMETER? He: as ; IGNITION ~~" Fe | DUMMY INSTRUMENT BOARD | ed 7m” sy « — - ; - 3 w w = sf WN F| t=j —_—_—— * al a S a Ss € MAIL & z COCKPIT I BAGGAGE a I ated AE &e a n Sam 4 we | = _ ‘en Ste = » a ew } a a 2 3, ws

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No Toy Will Gladd en Boy Like This the Heart of the Mod “Sides walk Plane,’ Wh a."

Page 142

314 POPULAR MECHANICS Model planes are doing their Oat part in a preliminary educational way, but to give the boy a more accurate concep- le v =}

TAPERED BLOCK ~.

ALL CROSS FRAMES LIKE THIS EXCEPT A AND B

PILOT LEGS GO THROUGH THIS FRAME

be i1-o FOR ATTACHING STRUT 4, '

<2 \

erate || Dg ™N

TOR ATTACHING WING TO FUSELAGE FRAME” ) CENTRAL RIB, 3 STOCK OTHER RIBS 3 Fic.2

~ tion of how a real plane is constructed and controlled, he should have a ship big enough for him actually to ride in it, The cost of the materials for the “Midget Mail” illustrated is negligible, though no little painstaking work is required. How- ever, balanced against the educational value, the wholesome fun and the satisfac- tion of making it, this little ground plane is worth many times its cost in time and money. The original plane, as shown in the accompanying photos, has been the greatest success of a long series of elabo- rate toys at our home. In fact, it has almost become a nuisance because so many children, from toddlers up to high-school seniors, are in convention around the }--+-9-+- 9-29-75 -+-8— 12-4

axe) ~STOVEPIPE WIRE

S ] AILERON-FRAME CONSTRUCTION house in their spare time waiting for the ship to be trundled from its hangar. There has been no abatement in weeks. The first step is to make the transverse fuselage frames. These are all similar in design with the exception of the one (A, Fig. 2) just in front of the cockpit. This must have provision for the pilot’s legs to pass through to operate the rudder bar, and also have room for the “joystick” when pushed forward in an imaginary nosedive. The corners of all frames are notched to receive the longitudinal members of the fuselage. The latter are of. 5¢-in. square section for the two bottom members antl 5¢ by 1- in. stuff for the top. The bottom pieces are smaller in section, because they are

=_aeecoerereQ

Page 143

POPULAR MECHANICS

FIN —~ - RUDDER = z ~ a — RS tonstavcrion / ABR > 8 ZK | / STABILIZER qa | | ge ; LE ‘ —"* | 4 EE n& A 7 ( {| | fe S a : 4 ' >>> ~ i, ae SY ES” WAS ~t WS SS. MAIN SPAR ‘* LIGHT SPAR =a WING ASSEMBLY Fic.3 FOOT CONTROL % BOLT +-~ FOR RUDDER b - CROSSPIECE SET IN p=—~ FRAME

} “7 ? ELEVATOR —”* “A 2 ~~ 7 SLAT | oF | PS) bse | CLEATS, SLAT 23 7 -“~ ° f F™ Li— 1 4 / a in Tr PIVOT E Ly wee Se A \ FF : — 9 ' S el MAIN \ , SLAT—" T % \ SPAR 3 X15 FRAME a AK ’ Le 4 30°—~- = > SUB- 4 € \ aq ! FRAME) Ae LUG FORFASTENING- | MAINSPAR Ag? ; WING TO FRAME Zx12 art | p. fe SCREWEYES PVE © — _ Fig. 4 DETAIL OF RIB CONSTRUCTION DETAIL OF STEERING DEVICE

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316 required to take a greater bend. The in- corners of all four members should be notched, about one-third through, with a saw in the front section so that they will bend in readily to meet the “radiator.” They can be drawn to- gether with stovepipe wire to meet the blocks provided for them on the inside of the radiator. Screws in the corners of the radiator board hold the latter to the frame members. Next install the running-gear supports. These are made from 2 clear pieces, side side or 24% by %-in. and streamlined where they are exposed below the fuselage. The ver- tical members come together at the top; the inclined ones are screwed to the side- members at top and bottom. A streamlined wood axle is secured to the supports with screws, and roller or ball- bearing coaster wheels are fitted to the ends with lagscrews. frame which does the steer- ing, one can use a strong coaster wheel with a steel fork, or a large, rubber-tired For the rear wheel, caster. Lacking either of these, a sub- stantial wooden fork can be made, such as was used on the original model. This. however, is not as satisfactory as the metal fixtures. In case a metal fork is used, two arms should be attached to carry the steering cables. This is a simple matter on the wooden type. Now brace the entire fuselage with stovepipe wire as shown, leaving the cock- pit compartment unobstructed for easy operation. The stabilizer and vertical fin are easily made, the elevator and rudder respectively being hinged to them by stiff wire running through This permits easy dismantling for adjustment or packing. The wing requires more skill than any other part of the ship, but if the diagram is followed and white pine used for the ribs, no trouble should be encountered. A main spar carries the bulk of the wing structure, supported by a light spar. means of a screwevyes., Each of these pass through holes in the soft- pine shaped ribs. There are thirteen of the latter, including the heavier center rib, which is 3% in.thick. All others are of 34- in. stuff. A stringer across the front edge of the Wing, and a flat piece at the rear (Fig. 3) contribute their part in making the wing rigid. POPULAR MECHANICS Short pieces, marked 1, 2 and 3 in Fig. 2, are securely screwed to spar and center rib, as indicated, to serve as means of fas- tening the wing to the frame. Similar blocks are attached to hold the upper ends of the struts. The curved pieces of the wing tips are made of 3-in. white pine. To give the wing the correct taper toward the ends, trim down the rib widths in pro portion to the distance from the end. The spars should also be tapered slightly, to permit smaller holes being bored in the outer ribs, After the wing frame is completed, sup port it on two boxes placed near the ends, so that it will sag slightly at the center. Then brace the top side with stove wire, as shown in Fig. 2. Wherever the wire crosses a rib or slat, notch the latter not over “46 in., so that the wire will lie below the edge of the wood. Now turn the wing over and brace it on the bottom side in a similar manner. There should be no slack in any of the bracing wires when the wing is completed. The best propeller is made from a single piece of soft wood, but the work can be simplified somewhat by making the blades separately from flat pieces of wood and inserting them in slots in a hub block and securing them with wooden pegs. The appearance of the propeller depends en- tirely upon the skill of the maker, and there is no very good rule to follow in mak- ing one. It is a job for a drawshave, a small plane and a gouge. A bushing made from a short length of brass tube will per- mit it to turn more easily on the carriage- bolt shaft, and its appearance will be greatly improved by facing the hub with a circular piece of sheet copper and stud- ding it with escutcheon pins. The joystick and controls are simply made, but important, for they give the boy action while he is learning imaginary take- offs, spirals, glides, dips and nosedives. The stick control, as well as the rudder, ‘s better illustrated than Wire cable is preferred to single-strand wire, picture wire being very satistactory. The cables in the rudder and elevator control can be guided through screweyes where required, but you will find small pulleys necessary on the aileron system for the that there are so many corners. Apply hard grease or graphite to the described. reason

Page 145

POPULAR MECHANICS 317 cables where they rub against screweyes. a great deal to spray it grav, orange, sky- A dummy instrument board, made from blue, willow-green or any shade that strikes your fancy. The landing gear and 2%. radiator should then be finished with <) 7

‘ L YY) JME Yr

1 | 1e 1 ¢ OAT OLal st n, ind n r ble discarded auto accessories, will add greatly painted on e fi ed O1 to the fascination of the craft, and should The young owner Oo! this sl ip may be include oil, gas and temperature gauges; assured that he will have a line of young tachometer or revolution counter; air- sters halt a block long waiting their turt speed indicator; compass; banking meter to coast downhill of be pus ied over level altimeter, all made of old ammeters, and pavements. Certainly it provides a tre throttle and ignition switch mendous thrill, and in a stiff head wind Tacking on the fabric, which is un- while coasting who know but that it bleached muslin, is very simple. Pull it might take oft It would nor tak grea as taut as possible over all surfaces, and deal of ingenuity to equip t ee we use small copper tacks. The curved parts pedal drive, taken from an old “bike of the wing can be fitted by tacking, but that the pilot would be independent o1 where the corners of ailerons, rudder, ver- “ground crew,” in the very unlikely event tical fin and stabilizer are rounded, a bet- that volunteer “pushers” were hard to get ter job will be done by sewing two pieces of muslin together to fit the curves. @ Don't wrap paper around lamp When the fabric is entirely fitted, it can serve as a shade t you go i ( he left in its original state, or vour neigh vet it. a fire might result from the he borhood auto painter will not charge you Use a glass or metal shade

Page 146

318 POPULAR MECHANICS Old Umbrellas Can Be Used to Make Guns for Shoot- ing Arrows; Strong Rubber Bands, Stretched as Indi- cated, Provide Power to Drive the Arrows Fast and Far ! | \---- SLOT IN CATCH \--RUBBER BAND Spring Gun Made from Old Umbrella An old umbrella stick, some strong rub ber bands and a few little odds and ends will gun that is hard to beat. With it any boy can have plenty of fun and learn to be a good marksman.. Strip an umbrella so that nothing is left but the steel stick, the handle and the ferrule that slides along the stick to engage with the make a Remove the catch near the lower end and drive on a piece of hardwood, about 3 or 4 in. long and with a hole drilled through the This is the crosspiece and should remain near the end of the stick. catches center. Drive a large screweye into the center of this piece and in line with the remaining near the _ handle. Solder a piece of stiff wire, which is bent in the manner catch indicated, to the top of the catch and file a deep notch halfway down the top edge so that the slot in the ferrule will fit over it when The terrule the catch is depressed. flange will be . found to contain many ~~ holes where the ribs of the um- brella were previously fastened. To two opposite ones, faste1 of heavy rubber band, about 1 ft. and attach their free ends to the cross- piece, as shown. Their length must be such that they have to be stretched to their limit when the ferrule is pulled back to engage with the catch. The used with this gun are made from slender lengths of tough wood properly balanced. Drive one or two pins into the butt to en- two strands long, arrows gage with corresponding holes in the fer- rule, as shown in the lower detail. If the arrows are balanced with feathers, be sure that these will go through the screweye without hindering the progress. To shoot the gun, pull the ferrule back until it engages with the slot in the catch. Fit the arrow in the screweye and set the pins in the ferrule holes. Aim as vou would a gun, and press down on the trig- ver. This releases the ferrule which springs sharply forward under the tension of the bands and shoots the arrow where pointed. It will be clearly seen that the speed and range of the arrow depends on the length and tension of the rubber bands. —L. B. Robbins, Harwich, Mass. arrow *s

Page 147

POPULAR Scalding and Hanging Hogs Here is a simple method of scalding hogs, which requires little water and en- ables one man to handle a large carcass without difficulty. After killing the hog, lay it on sacks, or preferably a piece of canvas, large enough to permit it to be turned over. Cover the upper side thor- oughly with sacks, so that there will be two thicknesses of material. Pour hot water, which is slightly below the boiling point, over the sacks, taking care that all parts of the body are covered. Remove some of the sacks and scrape off the hair, continuing until one side is completely clean. Then turn it over and scrape the other side. This method eliminates sous- ing and lifting. An way to lift a hog is as follows: Make a V-shaped frame from 2 by 4-in. stock, as shown, the legs being about 6 ft. or longer. Lay it over the hog, after the flesh is cut between the tendons and the bone of the hindlegs and a stick is inserted. Brace the legs of the frame and tie a rope to the gambrel stick. easy fastening the rope securely around the top of the frame. Now get a piece of 2 by 4-in. stock, about 9 ft. long, and also fasten it to the frame by means of a small rope. Drive a couple of spikes into this piece and into the frame to prevent the rope from slipping. When all is secure, push the 9-ft. brace until the carcass is clear of the ground. This is a job that a single man can perform easily —Edward Van Valkenburg, Silvis, Ill. also ~W f ’ & >” \ | Gy VG LS hts Easy Method of Scalding and Hanging Butchered Hogs Single-Handed MECHANICS 319 Method of Opening and Holding Overhead Windows in Any Desired Position Opening Swinging Windows That Are above Reach In a trip through a brass foundry the other day, I noticed a simple method ot opening overhead windows and them in any position desired. light but fastened to the window a pull would unlatch the window and swing it open. A spring was ~ cord was strong catch so that fastened to the upper window frame and the sash, as shown, so that the window had to be pulled against its resistance Several metal rings were tied to the cord and looped over a nail, as shown, to hold the window open in any position Phe windows were about 25 ft. overhead.—kK M Coggeshall. Webster Groves Mo, Staining Wicker Furniture Many purchase unfinished wicker furni- ture with the idea of staining it when it soiled bevond the cleaning stage | most cases oil stain is used for this pur pose, but. after a few months. the Water stain of penetration 1s Buffalo wears off 1s preferable much greater N.Y pow er me Georger

Page 148

320 POPULAR MECHANICS

TRAILER TONGUE ——— CUT FROM BREAKER STRIP ) 4 Clean both sides of a film, as the back is cov- ered with emulsion to TO REAR HOLES FOR) =prevent curling. Caustic OF CAR * _ccoupuinc =! : 5 ree . PINS soda can be used for cleaning glass plates, but 77 not tor films, for the rea- = COTTER . , acti . tween the two may cause 7° the film to take fire when “ it dries. The proper — caustic-soda solution for

Eliminating the Jerk a clothing in some suitable way. If possible, place the negatives on a rack to keep the surfaces sepa- rated. When the emulsion is softened and commences to peel away, transfer the plates to a tub of clean, hot water and scrub them with a brush.—L. B. Robbins, Harwich, Mass. . System for Watering Hedges and Terraces The photo shows an inexpensive water- ing system for hedges and_ terraces. Lengths of pipe are laid on the ground under the hedge, as indicated. The pipes are arranged to receive the end of a hose when watering is required. Numerous

Permanent Pipe Installation under Hedge Waters Both Hedge and Terrace holes drilled in the pipe permit gentle ap- plication of water.

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Sy °) Sam Brown Cc AN you do it?” Everywhere we are met with this question, and so the performer turns Can-You-Do-It man, and proceeds to en- tertain the evening party with a few easy “give- problems, and in- maybe, to-turn away” cidentally, the tables on the literary light of the party, who has stumped him with a simple like “What vear was Tutank- hamen born?” The first problem out of the bag is the “Long Reach.” number, the entertainer seats a of the audience in a chair, and places a cork, or some similar object, to the right question In this member and a little in advance of the subject’s left foot. The problem is to reach down be- tween the legs with the right hand, going around behind the left leg as shown in Fig. 1, and remove the cork. The sub- ject, of course, is warned that he or she must not slip forward on the seat of the chair, but must sit as first placed. Can you do it? You will, no doubt, affirm that you can if you are an average person, and have looked at all the pictures before reading the article. Even though you must not slip forward on the seat, the chair need only be tipped forward, as shown in Fig. 2, and the feat becomes quite easy. If someone handed you an ordinary soda straw, and asked you to lift a heavy bottle, using the straw only, vou would probably look him over carefully and then advise him to see a doctor. However, it can be done! Bend the straw, as shown in Fig. 3, in such a way that, when in- serted in the bottle, the short leg of the doubled catch under the straw will shoulder of the bottle, and enough of the neck to trick is longer leg will project from the and the the bottle selected for the trick must be of such a size and shape that the from the neck ; performer may be embarrassed by enable you to grasp it, done. Of course, long leg will project otherwise the not being able to do his own trick. Can vou touch one card in a deck; and only one, and make the entire 52 cards turn over? Well, why not? Lay the cards out as shown in Fig. 4, one overlapping the other in a long line. Now slip your finger under the card at the end of the line (the first card laid down) and start lifting it by its outer edge. Don't the card, lift it up with one finger. grasp This of course, will make the cards that over lap it rise also. Keep on lifting until the vertical, and then exert he right (Fig. 5), remaining cards will obligingly sometr card is a steady and the pressure to t sault for your benefit, and will finally assume the position shown in Fig. 6, over. A little how the completely turned ynerimentinea will e experimenting will show cards should be over lapped, and will demonstrate how the end rt card should be continually shoved in the 321

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322 POPULAR direction of the remainder of the pack, lest it turn completely over before an im- pulse has been given to those at the right. Place a water. It floats! but what of tt? Well, can you place a cork in a glass of water in such a position that no one can remove it without spilling every drop of water? a glass of cork in Sure it does, Of course you can! Simply place a sheet of heavy paper over the mouth of the invert the glass on the table, and then pull the paper away. Where’s the cork? Try and get it. Just a word of Inspect the glass before you use it, for a little chip on the edge may ruin your budding reputation as the “life of the party”! Imagine that you had only half of a match box—the cover—and wanted a whole one. Could you make it? Allow me: Simply cut the cover into three por- tions, A, B and C, as shown in Fig. 8, assemble A and B as in Fig. 9, then slip C diagonally into the opening between A and B, and there vou are! The finished box appears in Fig. 10. It is an odd- shaped match box, but it’s a whole box, none .the glass, warning: you less. Here is how you test the lungs of the audience, who are, by this time, breath- less with amazement—perhaps. Take a visiting card: and turn the ends down for a distance of about 4% in., forming a sort MECHANICS How the Cork Is Lifted; Left, Raising the Bottle with the Soda Straw or “tJ.” Piace this “UU,” table. card over by blowing. inverted, on the Now, the problem is-to turn the Can you do it? It’s not likely vou can, even if you are gifted with a pair of lungs like the wolf in the fable, who “puffed and puffed until he blew the wee house down,” unless you know the secret. Don’t blow at the card as is the natural thing to do, or even under it, but blow on the table, about 10 in. from one of the open ends, as illustrated in Fig. 11, and the card will turn. Here’s a new game with dice, to be play ed by two persons, with a die. die, say the one-spot. The second player also Fig. 12, this number is added to yours. The addition is continued and the first plaver reaching 50 with a show of his or her die wins the game. Simple enough, but can you always win? Certainly, here’s how: certain key numbers, 8, 15, 22, 28, 36, 42 and 50. You should commit these to memory, but that is an easy task. Now you must exhibit your die so that its spots, when added to the previous total, will equal one of the key numbers. To play safe, start with the one-spot, as mentioned above, and then, whatever your opponent shows, you need only add sufficient to it Each is provided You show one side of your and shows a number, There are to total eight, and so on. For example, if A (yourself) shows a one-spot, and B shows a six, the total is seven, and A must next show a one to bring

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*) POPULAR MECHANICS 323 Figs. 4, 5 and 6 Illustrate How the Pack of Cards Is Turned Over by Touching One Card: the Trick Is a Simple One the total to eight. B may no throw or show a three, which will bring the total to eleven, an A must then exhibit a four to bring it to fifteen. which is the second kev num shows a three, the total will be come eighteen. and A must show another four to hyrit o ++ to the third kev number. Continuing in this wav, A will alwavs have the deciding show ind will a Wavs W in the game If it hannet that B at any time shows a num = Fig. 7 Shows How the Cork Is Put in the Glass of Water So That It Cannot Be Removed without Spilling the Contents

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4 POPULAR MECHANICS If You Had Only the Cover of a Match Box, Could You Make a Whole One? Figs. 8 to 10 Show How It Is Done —— Turn the Card Over Merely by Blowing On It? Fig. 11 Shows How Easy It Is, Once You Know the Trick Fig. 12 Illustrates a Dice Game in Which You Can Always Be the Winner; All You Have to Do Is to Memorize a Few Key Numbers, and You Can Win Every Time The Problem Is to Blow the Match-Box Drawer through the Opened Cover and toward Y ourself Fig. 14 Shows How It Is Done

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POPULAR MECHANICS Here Is a Very Easy One; All You Have to Do Is to Take a Pack of Cards, Lay Them, Face Down, on the Back of Your Hand, as in Fig. 16, Above, Then Filip Them Gracefully in the Air and Catch Them Delicately in Your Fingers, as in Fig. 17. Try and Do It! Can You Lift a Number of Matches without Using Your Hands, with the Aid of Only the Cover of the Match Box? If You Can Produce a Good Vacuum, the Rest Is Simple ber that makes the total fall on a key num- ber, A simply shows a one-spot, and starts the process all over again. Here is another lung tester. Arrange a match-box and its cover, cut shown in Fig. 13. Now. standing on the side nearest to the drawer open, in the manner cover, can you blow the drawer toward vourself and through the bridge formed No, not suck it through; blow it through. It’s feally very simple. Take a magazine or book, and hold it in by the cov er? the position shown in Fig. 14. By blowing against waft the drawer through the cover, and thus accomplish the seemingly impossible. this you can The entertainer now arranges a number of matches on the table, side by side, so that they form a compact square. The problem is to raise the matches from the table. using the cover of the match box only, and this cannot be held in the hands Can vou do it? The solution, as usual, 1S and is Fig. 15 h- is held in the mouth. By placing the other end over the easy, illustrated i1 match-box cover matcnes : . ‘ and sucking in the breath sharply, the resultant vacuum will cause the matche to adhere to the open end of the box, an | thev can be lifted several inche Now for one that really justifie the title of this article. The performer e

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326 POPULAR hibits an ordinary pack of cards. He the back of his hand, as shown in Fig. 16, and then, rais- ing his hand smartly, he somersaults the cards from the table and delicately catches them in his fingers, as illustrated in Fig. 17. But can you do it? places half of these on Trap for Catching Moths at Night At summer cottages where moths and other in- sects get into the house every time the screen door is opened, espe- cially at night, the trap illus- trated found effec- tive. Rolla piece of fly paper to form a cylinder with+the sticky coating on the will be outside, and pin the over- . lapping edges together. From a length of w ring that fits on the electric lamp, leaving the ends of the wire extending on opposite and pushing them through the wall of the cylinder from the inside, near one ire form a top of an ordinary sides of the ring end. The cylinder is then hung over a lamp, as shown. The bulb should, of course, stand upright and there must be plenty of space between it and the prevent the heat from causing the coating on the paper to run. The light attracts the in- sects and they are caught on the flypaper. —William C. Thomas, Chicago, cvlinder to Use of Pack Films in Cut-Film Magazine Like a great many other photographers, the bulk of instead of glass plates, I use a now do their work on cut films, cut-film magazine. I[ usually carry a few film packs. Once on a photographic trip remote from any supply store, I had used up % 1] l of my cut films and then found that MECHANICS a leak had developed in the light trap of the only film-pack adapter I had with me However, I had a changing box, and at tempted to load. pack films into the cut film the the changing box, and putting the films into the partitions of the cut-film magazine. With this arrange ment, I found that the pack films could be inserted without any trouble, provided care was taken when pulling off the paper magazine by tearing pack to pieces inside of tabs, and that they seemed fairly secure In taking pictures with this outfit, the dif ferent exposures could be turned up in the cut-film without any ten dency of the pack films to drop out of the partitions. magazines The development of the ex- posures produced a set of negatives that were entirely satisfactory. This kink en abled me to take twenty-four additional photos. The method can be used with ordinary two-shot cut-film holders.— J. E. Hoag, Los Angeles, Calif. same Cleaning a Stopped Sink The other day a stoppage in the kitchen sink ! required the improvising of a device to clear it, as there was no tool at hand for the purpose. An old tire pump, a of sheet rubber aa ‘@ fs ¢ ‘rr piece and a wooden plug turned the trick. The plug : was about 1 ~~ f in, thick in. in diameter. This was bored, through half its thickness, © > yi —~ WOODEN ~ BLOCK and 3 -RUBBER DISK with a bit slightly smaller than the pump barrel, and the rest of the way with a 1-in. bit. A disk, as shown, was cut from the sheet rubber and stretched over the bottom of then drawn tight with The pump barrel was unscrewed from it foot stirrup and The whole device was the plug, tacks. screwed into the plug. then set drain opening and the handle of the pump over the

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POPULAR MECHANICS forced down. If the stoppage is far from he sink opening, water pressure must be used to force it away, instead of air. Have pail of water handy, or fill the sink with ater. Then fill the pump barrel and force the handle down as before, after the pump as been placed over the drain. Several harges may be necessary before the ob- truction is removed. Lock for the Cellar Trapdoor Inclined cellar doors of the kind shown 1 the drawing are seldom locked. A pad- lock may be used for this purpose but it s rather unhandy. A simple and effective latch can, however, be provided, which is opened by merely pulling a cord and closes automatically when the door is shut. It consists of a strip of rubber band cut from an old inner tube, a hook and staple and a length of cord. The hook is pivoted to the door jamb and the staple is driven into the underside of the door in line with the hook, so that the latter, when swung back and forth engages and disengages with it. The rubber band is then tacked to the door jamb and is connected to the hook by means of a cord, The band should be slightly stretched when the hook engages with the staple. Another cord is tied to the hook but is run in the opposite direc- tion, to any convenient point. Pulling this cord releases the hook from the staple, while, when the door is closed and the cord loosened, the rubber band pulls the hook back into engagement.—Mlrs. Orville J. Kaiser, Warrensburg, Mo. Simple Locking Arrangement Which Is Handy to Use for Inclined Cellar Doors 327 Air-Rifle Bullets Can Be Saved and Used Over Again with This Target Target Saves Air-Rifle Bullets A target for air rifles which will save the bullets without deforming them, so that they can be used repeatedly, may be made from a fairly large wooden box and some heavy cloth. The cloth is hung in- side of the box, without touching the back, and is nailed only at the top. After the bullets have passed through a paper target tacked to the front of the box, they will strike the cloth and, their force being prac tically spent, drop to the bottom, where they can be collected.—E, T. Ir.. Humboldt, Lowa. Gunderson, How to Make Flypaper Linseed oil, rosin and honey, which are readily available, can be used to make a good sticky flypaper. Melt a lump of rosin in linseed oil until the mixture the consistency of a thick paste. Do this over a fire, so that the rosin will not burn. Then add about one-third the volume of clear and stir thor- oughly. Apply the mixture while it is hot to sheets of heavy wrapping paper with a stiff brush, and when the cooled thev will have a sweet, sticky face.—L. B. Robbins, Harwich, Mass. assumes. slow honey have sur- sheets

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328 POPULAR

MAGNETS MECHANICS everything except the magnets, leaving them attached to the base, which is then attached to the wall at such a distance above the catch that, when an electric current is sent through them, they will raise the catch. If radio inductance switches are not available, get three bakelite or hard-rubber

CATCH ON DOOR ~e-----<----

@ ' Combination Electric Lock for Sliding Door Which May erated at a Distance Remote-Control Electric Combination Lock for Sliding Door A novel electric lock for a sliding door is shown in the drawing. The current to operate it is obtained from a battery of three dry cells, a 6-volt storage battery or a bell-ringing transformer connected to the house-lighting circuit. The lock con- sists of a magnet taken from a doorbell or buzzer, a latch securely screwed to the sliding door, a soft-iron catch to engage with this latch, and three radio inductance switches or sets of switch points and levers. The latch is made of some hardwood, oak or ash, for instance, and is screwed to the door at any convenient height so that it projects over the door jamb or the wall about 3 in. It may be made of brass, if preferred, but not of iron or steel. The soft-iron catch is pivoted to the wall so that, when pulled up, it will just clear the latch, and when at rest, it engages with the latch, keep- ing the door locked. Strip a large elec- tric doorbell of wooden

RIVETS~

Vegetables in a Display Window Are Exposed to a Constant Spray of Water disks, about 3 in. in diameter, dri!] 12 holes in each disk for switch contacts and one in the center for a switch lever, or the disks may be cut from small phono- graph records. Set the disks in line on a panel in the place from which the lock is to be operated. Connect the points and levers as indicated. Choose switch points in different positions on each disk to make the combination that works the lock difficult to dis- cover by persons “not in the know.” To make it possible to operate the lock, the latch should drop into place loosely when the door is tightly shut. To open the door, turn the switch levers on the disks until each makes con- tact with the wired point. The setting of the last lever completes the electric circuit through the magnets, and the catch is — raised so that the door can be slid aside. Then turn the switch arms to break the circuit. The combination can, of course, be altered at will by changing the wiring to the switch points.—L. B. Robbins, Har- wich, Mass.

Be Op- Sprayer and Drain for Vegetables Vegetables on display in a large Colo- rado store, are kept fresh by a fine spray of water which is kept up all the time. The display also attracts attention as a novelty. A sink in the window is fitted with a wire- mesh tray having a number of compart- ments and a pipe with suitable sprays above it, as shown in the photo. —Charles A. God- dard, Los Angeles, California.

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Making a Chinese Screen By HERBERT C. McKAY | ECENTLY miniature Chinese screens have become very popular, but their high price puts them out of the reach of most of us. By the method described here, these screens may be closely imitated, and the designs altered in cases Chinese touch is not wanted. The original screens are made of two thin slabs of colored stone, the first layer being pierced to show the surface of the underlying stone and the two mounted between two uprights of black wood. In making our screens, we substitute different-colored celluloid for the stone slabs, and use the same ma- terial for the supports. The pieces are then assembled with celluloid where the contrasting two sheets of separate cement, which makes the operation mS quite simple. The materials needed are: 2 sheets of black celluloid, 5 by 7 by and 3 by 11 by &% in., respectively 1 sheet of white celluloid, 5 by 7 by % in and 1 tube celluloid cement. The 5 by /7-in. squared and the coarse-toothed a Ill, sheets are edges smoothed. A blade will this material more satisfactorily than a finer carefully saw work one, as the heat generated by the fine saw tends to melt the fragments removed from he sheet into a paste wv iich ce ments the material behind the blade The black sheet is then sandpapered thoroughly on one side until all the gloss is re moved. The design to be used is drawn on this side with a colored pencil sharpened to a fine point Phin-lead red pencils are very useful for this work design is cor eted, it When the sawed out in the usual manner, using either a hand or powet fretsa As the celluloid will crack near the end i cut this ¢ must be careful done, a when completed, there will be seve rough places in the tretworl Phese

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POPULAR ire eam nnn Sle eB so - fe. or ete are removed with a coarse-cut file of knife- blade shape. Round and half-round coarse files will also be use- ful. Aiter the prelim- inary smoothing, all sawed edges are care- fully finished sandpaper. with The white now sanded the surface is The back of the black design is with celluloid cement, then laid upon the white sheet, and both placed under pressure for about two hours, when they should be firmly united. sheet is until matted. coated In the meantime, the sidepieces are cut out. These de- photos, desired the mav be of any The design shown in sign. or one similar to it, be economically may cut out of the 3-in. strip of celluloid by tail,” is, with the foot or base of one piece laving out the sidepieces “head to that at one end of the strip, close to the side, and the foot of the second at the other end. In this manner, the width of the bases mav be made a little over 2 in. The width of the upright portions should be 34 in., or a little over, so as to allow about Mg in, of overlap on the panel, when as- sembled. The over-all length, laid out in MECHANICS this manner, will be about 10 in. If any other design, demanding a wider base, is selected, it will be necessary, of course, to obtain a correspondingly wider piece of material. When they are cut out, the edges are smoothed with a file, and one side is sandpapered until mat. is laid on a table, dull side up. One _ sidepiece One edge of the combined sheet is given a thorough application of cement and gently placed held so for a turning it upside down, the assembly is put in a vise in such upon the sidepiece. It is few moments; then, a manner that the stand or sidepiece lies on top of the screen. Now pre- pare the sidepiece and it in the same When this done, and the cement other fasten way. has been partly set, bind the whole with string and put it away tor twenty-four hours to set completely. % & as ~ Eee y Bi Cad ES we Sara If no cement is at hand, it may be made by mixing one part acetone and two of amyl acetate and adding to the mixture a few shreds of transparent celluloid. A camera film, 1 by 2 in., finely shredded, suffices to ripen 2 oz. of the mixture.

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POPULAR Protection against Vermin In mountainous sections, pack rats, weasels and other kinds of vermin are quite common, ~-They force their way into boxes of food, bedding, and, in fact, everything. To exterminate them is im- possible, and the best thing to do is to arrange things so that they cannot do any harm. One method, which I have found highly successful, is to place each leg of. a table in an empty coffee can. The crea- tures, even if they gain access to the cabin, cannot climb over these cans. Thus, whatever is put on top of the table is per- fectly safe from them. Another practical scheme is to line the inside or outside of clothing chests with sheet metal, prefer- ably tin, to prevent the animals from gnawing their way through. As many things as possible should be kept in cans or tin-lined containers—Henry H. Gra- ham, Twin Falls, Idaho. Homemade Tumbler Holder Tumblers set on window sills, tables or other painted or varnished surfaces are likely to leave water marks and are also in danger of being knocked down and broken. A wall tumbler holder, which will prevent these risks is shown here- with. It is made from a length of No. 10 or 12 galvanized-iron wire, bent into a circle, about 14 in. larger than the bottom of the tumbler, then brought down about 2 in. and formed in- to a smaller circle directly under the first. The diameter of the second circle should be less than that of the tumbler bottom. Finally, bend. the wire out horizontally, then up at right angles, and form an eye at the end for a wood- screw by which it is fastened.—W. C. (a Thomas, Chicago. @A hot-water bot- | tle held against a porous plaster will assist moving it from the skin. in quickly re- MECHANICS 331 Economizing Space in a Dishes on Each Other Refrigerator by Piling the More Space in the Refrigerator If your refrigerator is small and gets overcrowded, obtain some thin from an and cut pieces large enough to reach across the dishes placed in the refrigerator. Deep dishes lumber orange crate should be used whenever possible. With the boards arranged as shown, several dishes can be piled on each other. The boards should be scalded occasionally to Pieces of slate from roof covering also mav be used for the purpose. If economy is no object, get a dozen wire shelves similar to, but smaller than, those already installed in the re- frigerator. Meats and vegetables can be piled on the shelves without the dishes.—James F. Hobart, Dunedin, Fila. keep them sanitary. some Restiffening Straw and Panama Hats panama hats that become flimsy and soft from usage. or from be coming damp, may be restiffened easily. Dissolve 14 OZ Straw or very of gum arabic in pt. of water and use this to sponge the in side of the crown and the underside of the Allow the hat the sun, and it will have the required stiffness. brim. to drv in

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~~ we 2 POPULAR Improvised Beading Plane for the Home Owner's Tool Kit Is Used to Make Molding ° Improvised Plane for Making Molding Paneled walls add to the appearance of a room and this method of decoration is well within reach of any home owner if he is handy with tools. The molding used for this purpose has a number of small grooves and ridges, and is not always ob- tainable at lumber yards. It can easily be made, however, by means of an impro- vised plane shown in the drawing, if a regular carpenters’ molding plane is not at hand. The homemade tool consistsoftwo pieces of wood, grooved along the bottom edge to pro vide chip clearance, and diagonally to accommo date a cutting blade. The blade can be made from a section of discarded file or similar steel, one end of which is ground and carefully whetted down to a sharp cutting edge shaped to produce the beading desired. It is clamped between the two sections of the hold- MECHANICS er and two bolts or screws keep them to- gether securely, Molding should be made from close-grained wood. Pyrethrum-Soap Spray Pyrethrum powder is non-poisonous to humans, and can be applied to vegetables or fruits just previous to consumption, but it is deadly to many insects. It can be applied with safety to tender plants without running the risk of burning the ioliage or discoloring the flower. It is easily sprayed with a dust gun. I have used this remedy successfully against the cucumber beetle, potato bug, cabbage worms, roaches and flies, as well as against the Japanese beetle. Spray the soap around the walls of your rooms, and a few minutes afterward you can sweep up dead flies on the floor.—August Jeffers, Louis- ville, Ky. Pipe Frame on Auto Holds Canoe It is often rather difficult to find a suit- able method of carrying a canoe on an auto when going for a camping trip. The writer made a special frame of pipe for this purpose, which can be attached or detached in a few moments, is not in the way, and has proved satisfactory in every respect. The canoe is held in place on the frame by means of thumbscrews and heavy trunk straps, the latter being slipped over the bottom as indicated. An outboard motor for the canoe was se curely attached to the spare-tire holder.— E. S. Mason, Norwood, Ohio Pipe Frame on Auto Makes a Strong Support for the Canoe When Out on a Camping Trip

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POPULAR MECHANICS 333 Portable Heated Dog House The portable house shown in the photos is used during the winter to provide a comfortable place for my dogs, and is accessible to them at all When warmer weather arrives, it can readily be detached from the basement-window sill to which it is fitted, and stored until it is again needed, With this arrangement, the dogs, while out of doors, have access to a sleeping and lounging compartment of times. Comfortable Winter Quarters for Dogs Are Heated with Warm Air from the Basement; the Entrance Has Four Curtains to Keep Out the Cold Air practically the same temperature as the basement, which is heated by a furnace. The window is, of course, kept open and a screen is substituted. The house is made of tongue-and-grooved stock and is lined throughout with paper. Any opening at the joint between the dog house and the frame of the cellar window is stuffed with cotton, to prevent cold air from entering the basement. The dogs enter through a vestibule in which four curtains, spaced 6 or 8 in. apart, are hung. After a dog has passed under them, they drop back so that very little cold air gets inside —F. C. Man- ning, Newark, N. J. Preserving Old Leather when old, often cracks on the surface and becomes “powdery.” vent Leather, To pre- this, a good dressing can be made from the following ingredients; lanolin (anhvdrous) 14 0z.; beeswax, 1 oz.: cedar- wood oil, 2 fluid oz.; and hexane, 22 fluid oz. First dissolve the wax in the hexane in a warm place, taking care to keep the latter away from fire as it is inflammable. The cedarwood oil is then added, and last- Iv the lanolin, which should be softened > by warming it. Be- fore applying this mixture, wash the leather with water and let it dry in a warm room for two or three days soapy Some of the dressing is then rubbed in with the hands, The leather will feel greasy, but after 48 hours it will be quite normal. When the dressing has been thorough!y absorbed by the leather, it may be polished. effect of 1 rhe this dressing is to soften the leather and restore its freshness, Lock for Sliding Windows Sliding windows of the kind used o1 sun porches are sometimes left unlocked unintentionally. An automatic lock shown in the drawing. One leaf of a row hinge, about 3 in. long, is screwed to the window the stop. frame on the side opposite The hinge should be set so that the free leaf forms an angle of 10 or 15° wit! the window slide when it drops into a } l recess cut in the lat- hown. To open ter, as § raise the leaf with one hand and slide the back Wi ith +] The hinge pi: the W indow free window a other. should be leaf will drop kept oiled so that the into the recess indow 1s Bay side. N. Y by its own weight when the w closed.—Frank W. Harth,

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334 POPULAR MECHANICS DETAIL —— Novel Weather Vane Comprising Three Wise Owls Sitting on a Twig ‘ Novelty Weather Vane This weather vane works as well as any other type and will attract attention. Three wise owls in varying poses offer the necessary resistance to the wind to turn it. The birds are cut from rather heavy sheet metal with a cold chisel, and are then brazed or riveted to a rod whic! is hammered out to resemble a tree twig. To the center of this twig a small straight rod, with its lower end pointed, is riveted or brazed. This rod is set in the end of a vertical gas-pipe support, which is split and bent at its lower end and drilled so that it can be attached to the roof with lagscrews. A hardwood plug should be driven into the lower end of the pipe be- fore it is placed in position, to provide a support for the pivot rod. Pour some oil into the pipe so that the rod will not rust. Painting the tree twig black and owls black with white eves completes the vane. The size, shape and arrangement of the birds on the vane in the drawing must be followed, for one side must offer greater resistance to the wind than the other, o: the vane will not turn into the wind.— Dale R. Van Horn, Lincoln, Nebr. Cleaning Paintbrushes Turpentine is one of the most satisfac- tory materials for washing paintbrushes, but it is expensive. Unless the turpentine can be used again in paint after washing the brush, the cheaper kerosene will do as well. After washing with kerosene, rinse in gasoline and shake out thor- oughly. If brushes are to be put away for some time they should be well washed with soap and water, thoroughly rinsed in clear water, and then hung, with the bris- tles down, to dry. Brushes that are to be used in a few days may be hung into a can of kerosene or turpentine with the bristles submerged. Drill a hole through the handle of the brush for a wire hook so that the brush can be suspended from the edge of the pail, without touching the bottom.—A. T. Bowden, Ottawa, Can. Improvised Strip Cutter Small strips of wood, such as are used in the construction of kites, model air- planes, etc., are very often difficult to ob- tain. The writer found that the wood from which vardsticks are made is a very suitable material for such sticks, and it is easily cut into strips with a safety-razor blade. A suitable holder for the blade is made from two pieces of hardwood, held together by three screws that serve to clamp it firmly. The blade is set at an angle to make it cut easier. The lower edge of the guide block is grooved “¢ in., or the width of the strip that is to be cut. In using the cutter hold it rigidly up against the woo d an d push along, being careful not to bear down too hard for the first time. Cut about haliway through the Xa wood, then ui turn it over RAZOR BLADE and cut it through from the other side.—Chas. Homewood, Hollywood, Calif.

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All Shop Notes published in 1927, in book form—Fifty Cents—from our Book Department Artistic Doorplates Beautify Home - By MAURICE M. CLEMENT fines other day my wife had an idea. Not objected immediately that, while the idea that this is anything to rush into print was a good one, I didn’t want to go dow1 about; she gets them often, and her ideas town to hunt for a picture that would fit have made our home the talk of the neigh- borhood for sheer behind the = narro glass panel, That objection beauty and comfort. But this idea was so simple and the results so splendid that it is very much worth while killed at once, howe, er. when she produced a last vear’s calendar that she had been sav- passing on Her idea was that the glass plate on the The Ordinary Blank, Unattractive Glass Doorplate at the Left Is Transformed into a Thing to Be Admired with the Aid of a Pair Some Scrap Wall- 1Ol€ swinging door between the dining room and kitchen had rather a blank look, and that it would be the easiest thing in the world of Scissors Sc paper, Pictures or Thin Lir m to change this condition. ing, womanlike, because and make it an attractive the picture o t was “too ornament, simply by put- pretty to ft ting some kind of a pic- She trir ec c tt} re ture under the glass. I size of the glass while

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336 POPULAR and a few minutes later we stood back to survey our work. “Isn't it beautiful?” cried my wife, her face aglow. I was compelled to admit that “What about the plate on the door?” |] demanded “It's inside the kitchen, and hardly any- body Why not stick an old piece of linoleum or wallpaper under the glass? This I said in jest. She opened the door and looked thought fully at the inside plate. “An “We have two fine figured linoleum and a dozen got the screwdriver, t we l Was. } other side of the ever sees it. excellent suggestion,” said she. preces oft small pieces of wallpaper in the garage > Non-Reversible Reamer Holder When hand done with a reamer held in a vise and the work in the | reaming is REAMER TIGHTENING if HOLDER SCREW > | HOLDER PIN i LOCKED RELEASE DIRECTION } DIRECTION VISE Bock) 4 Holder Which Prevents Turning the Reamer in Left- and Direction often that the work is toward the left when it is re- moved from the reamer, This soon dulls the edge and spoils the tool for finishing hands, it revolved occurs work to size. A good method of avoiding this trouble-is to use a vise holder like that shown in the photo and drawing. It locks avhen the reamer is used in the or- dinary way and releases when the oppo- site movement is attempted. To make the device, take a piece of square or rec- MECHANICS Get them, and we'll see how they look.” It was useless to protest that I was only joking, so I got them, and, before the evening was over, we had learned many things about “picturizing” doorplates. For instance, the linoleum and wallpaper sug gestions which I had offered in a facetious mood proved to be an absolute knockout. Three other calendars furnished subjects for as many plates. Popular magazines of the larger size yielded innumerable pic tures, drawings and reproductions of oil paintings fit to put under glass. decalcomania designs mounted on parch- ment proved particularly attractive. Several tangular steel, drill and tap it in the center. Next make the reamer holder of round steel, threading it on one end to fit the tapped hole in the block and drilling it out at the other end to take the reamer. Drive one pin into the block and another into the holder, their heads being slightly less in thickness than the pitch of the thread in the block. The pins will pre vent the holder from turning when it.is used in a right-hand direction, but when used in the opposite direction the holder itself turns. One clears the heads of the pins so that further turning revolution the work in the wrong direction only re sults in holder.—Harry Moore. Rosemount, Can. unscrewing the Using Erasers To erase fine lines use a sharp or nar- When erasing broad or thick lines hold an eraser at an angle of about 15° to the surface of the paper, alternating the sides of the eraser. This procedure will prepare the eraser for the finer lines. It will be found that bette: work can be done by erasing a small sec row-edged eraser. tion of the drawing and redrawing than by using an erasing shield. The should always be used carefully. surface of the drawing paper or eraser If the tracing has been roughened by careless erasing. the drawing will gather dirt. Never use an ink eraser on tracing cloth. It longer to erase with a soft eraser, but the surface is left smooth and the ink flow better when applied. When an eraser becomes hard and smudges the drawing, takes will

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POPULAR MECHANICS 337 can be restored to good work- ing condition by rubbing vigor- ously on a clean piece of drawing paper. If you have roughenéd tracing cloth by erasing; the: ink vill have a tendency’ to spread. [his can be prevented by dusting the surface with soapstone or or linary talcum powder, and wiping off the surplus before applying the ink.—Frank N. Coakley, But- falo, N. Y. Milk-Cooler Spout Shifts Automatically The accompanying photo shows a milk cooler on the farm of L. C Young, of Montgomery, Ala he delivery nozzle of the coolet is equipped with a double, tilting spout, of such a length that it can discharge into either one of two cans placed as shown. The spout is fitted with a float, dropped into one of the cans, so that this first to be filled. As the milk rises in this can the float also rises, until, when the can has filled to the proper level, the float tilts the spout so that it discharges into the empty can. Each can is filled uniformly, and all the which is 1 61 can will be the been operator has to do is to have an empty can ready to replace the filled one—J. C Allen, Lafayette, Ind.

Spout of Milk Cooler Which Shifts Flow of Milk from Full to Empty Can Iron Hook Pivoted to the Center Bar of a Truck Facilitates Han

<< dling Tote Boxes Adjustable Tote-Box Truck Handles Boxes of Varying Height [In a shop where small or medium-sized tote boxes are used, it is an easy matte to arrange a truck to carry them about An iron hook is piv ot the truck trame from place to place oted to the center bar as:shown, so that it can be slipped ove! the edge of a box, while the rear part is The should be heavier than the pedal used as a foot lever to raise the hook latter part so that it will not slip off the side of the box. A number of holes are drilled at regular intervals in the center bar so that the hook can be attached at various heights to suit boxes of different sizes The device is held in place by a bolt and nut.—Avery E. “| Granville, Cleveland, Ohio, Homemade Floor Oil A mixture of equal parts of turpentine and linseed oil is recommended for pine floors. Most floors will readily two applications of this mixture, and it will leave no objectionable coating. For absorb varnished floors, use one part of linseed oil to three of turpentine. Barely moisten the mop with the preparation. An occa sional slight oiling prolongs the life of varnish considerably.

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338 POPULAR Non-Slip Base for the Camera Tripod Can Be Made of Furniture Webbing Cure for Slipping Tripod The accompanying drawing shows a simple device which will prevent a camera tripod from skidding when it is set on steep or slippery inclines, or on polished wooden or marble floors. It consists of three strips of heavy webbing, each 22 in. in length and arranged to form a triangle, as indicated. At each corner a piece of rubber, 4 in. thick, which may be cut from a discarded auto tire, is placed underneath the webbing, the straps overlapping above it. A sheet-metal socket for the tripod leg is placed on the webbing at each corner and the assembly riveted together.—Leslie H. Phinney, Springfield, Mass. Oil-Seated Valves for Hydrogen Sulphide In order to prevent valves of the ordi- nary type from clogging up when used for hydrogen sulphide, and to forestall the loss of gas with its attendant discomfort, often caused by careless students, special valves have been installed by the Univer- sity of Oregon in the chemistry laboratory. In. the construction of these valves use was made of an oil-sealed trap. Each valve consists of two cylinders, approximately 13 in. in height, and connected at their bases by a small tube. The larger cylinder, > 44) . no 2 oe oe 2 — . MECHANICS which is made of 2-in. galvanized-iron pipe, contains a plunger of 1%-in. pipe, 8 in. long and plugged at both ends. The plunger, of course, makes a sliding fit in the cylinder, and can be raised or lowered by means of the rod screwed into one of the plugged ends and extending through the top. The smaller cylinder, made of l-in, pipe, is tapped and fitted for two 4%- in. gas connections. The intake is located about 4 in, from the top, while the dis- charge pipe goes through the closed top of the cylinder and extends downward 8 in. Both cylinders contain oil. The de- sired level of oil can be maintained by means of a small drain hole fitted with a removable plug about halfway up on the smaller cylinder. When the plunger is down, the surface of the oil is at its highest, that is, even with the plug. It is also about 3 in. above the end of the dis- charge pipe which dips into the oil and consequently is effectively trapped, or closed. When the plunger is lifted, the oil level falls below the open end of the discharge pipe, and the gas that was con- fined in the chamber above flows out. When the plunger is released, it settles back and the oil level rises again, auto- matically sealing the discharge. Pressure in the mains is regu- lated so that it never ex- gas DISCHARGE. COMPARTMENT * TO INTERCEPT OlL IN GAS ceeds the pres- a | sure of the 3- Fe in. column of atic 1) oil. To pre- “SL vent oil from wate ( being blown 1 out of the dis- il _ ss DISCHARGE Ff | charge pipe, a TUBE -----f=! 4). small com- rm partment has 'CVUNDER | been provided in the top of @ the smaller —- 144" PLUNGER’ cylinder to 2” CYLINDER - stop the oil while gas is flowing. Mica gaskets with a tiny perforation are put in the unions on the intake line, close to the valves, in order to cut down the flow of gas to the valve, as a great quantity is never desired. A wooden box, 14 in. high, 6 in. wide and 3 in. deep, houses the assembly. agcwiao wTwaekaATr we Oo

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POPULAR How to Remove a Broken Spindle Bolt [ had to remove a broken spindle bolt rom the axle fork of a Chevrolet. I had itended to saw a slot in the bottom of he bolt and turn it out with a screw- lriver, but the bolt was casehardened and his made sawing impossible. I first took ff the nut and washer, after which the hreads at the bottom were well doped ith rust-removing fluid. The bolt hen turned as far as possible by means was fa punch stuck into the cotter hole. A ece of 20-g about ft. long, was wrapped once around the It where thé washer had been, and. hile both ends of the wire were held rmly in the hands, a steady pull was ex- erted toward the left. The friction of the ire loosened the bolt, although it had een in place several vears.—Neil Nelson, Mo. auge soft-iron wire, Sansas City, Moving the Kitchen Range One of the most awkward and heavy ticles to move about is a kitchen range, d as nearly all the individual parts are castings, must be taken to avoid breakage. To facilitate the task, two 5-ft. lengths of 1%-in. iron pipe, with hooks attached, as shown in the detail, can be used. The handles extend beyond the ends of the stove, and two men can readily carry it. care Hardware dealers will appreciate a pair of thése handles. Carrying a Range with the Aid of Two Handles Fitted with Hooks MECHANICS 339 Ye Adjustable and Comfortable Seat for the Garage Worker Greasing an Automobile Seat for Auto Greasing Attendant After going to the trouble of provid ing the garage with two of the usual in clines, so convenient for greasing and re- pair, it was found that their use caused more or less discomfort for the attendant underneath. After con- sideration, the problem was solved by pro- working some viding a seat as shown, which can be ad justed to suit the worker. make up the Tw oO board : backrest. and four lengths of 2 by 4-in. studding form the frame, and two small bolts hold the sepa rate parts seat holes in the backrest sidepieces permit adjustment, together, while Steel Wool for Oilcan Strainer The man who wants to keep his oil as free from dirt as possible, will find it ad visable to put some sort of filter at the base of the spout. A piece of fine copper or brass gauze is commonly used for this purpose, but if it cannot be obtained, a small wad of steel wool may be substi tuted. This makes an excellent filter and is even better than gauze, but it be changed often. should

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340) POPULAR OUTER TUBE -- ASSEMBLED VIEW Adjustable Measuring Can for the Shop Eliminates Guessing and Weighing of Small Material Adjustable Measure for the Shop Factory stockroom workers who issue materials by weight can save a lot of time by using the adjustable measuring can shown in the illustration. One of these, kept in a barrel of material for which it is to be used, can be quickly adjusted to measure any quantity within its capacity, and so save the trouble of guessing or weighing it. Two lengths of tubing of convenient size are required, one to slide within the other. The inner one is closed at one end by soldering a flat disk to it, and the edge of the outer tube is cut toa spiral, as indicated. Drill a hole in the inner tube for a screw and_ use washers, little thinner than the tube and the other large enough to tighten on the outer tube when the wingnut is turned. Make a mark on the inner tube and graduate the outer tube, along the spiral, in sections to correspond with the weight contained in the can when the outer tube is turned to bring the marks in line. In use, the nut is loosened and the outer tube turned to one, two or three ounces, or pounds, as the case may be, the nut is tightened, the can filled to a heaped measure and leveled with a stick. two one a MECHANICS How to Cool a Hot Bearing Some machine bearings continue to get very hot no matter how much ordinary oil or lubricant is applied. Even when mixtures of oil and graphite, powdered mica, soapstone, ete., fail to reduce the heat, there is one substance, namely co- conut oil, that I have seen tried a num- ber of times, and in every case the bearing, to which it was applied, cooled down and the machine was kept running without a shutdown. Even after the bearing gets very hot, the use of this oil will generally cool it in a short time. On bronze and brass bearings coconut oil seems to work like magic. In cool climates the oil may get too thick to be fed from an ordinary oilean, but a little heat applied to the can will thin the oil. A bearing cooled by using coconut oil does not require flush- ing out after its use, as is necessary when mica, soapstone or some other “last-hope” remedy is tried—James E. Noble, West Vancouver, Can. Watering Trough for Hogs Hogs like to wallow in mud and water, and will upset any trough. A Texas rancher made the circular concrete trough shown in the photo, which cannot be overturned. It has a float in the center which, when properly adjusted, keeps just ordinary Circular Concrete Watering Trough for Hogs Cannot Be Overturned enough water in the trough for the hogs. L. A. Wilke, Fort Worth, Tex, @ When filling nail holes in yellow pine, use beeswax instead of putty, as it matches the color well.

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Build Your Own Gara + by R-O-BUCK and ) fr Mes Avex HWMICHELSON ff, f% X 7 Me tm | Sah PART II i ime yuilding is now ready for siding. ing paper, placing one length of paper This should be done before putting on ata time, starting from the bottom, and on the roof boards so that the top pieces boarding over this until I reached the of siding can be notched to fit around the top of the paper, after which another was rafters, with the applied in the same top edge flush with manner. the bottom surface of the roof; boards Do not fail to do this, as it is much more difficult to block the openings between the plate and tlie roof boards after the roof is on. The paper makes the garage wind-proof and much warmer. The siding was sawed lush with the two- \y-fours that formed the door and window open f 1 | Fic.8 ings. By following There are several this method, only a tvpes of siding on _ OVERHANG few hours were re- the market, the ("MOTH OF PLATE quired to inclose most popular ot AE Ve i a ee 5 6 7. the entire garage. which are shown by Fig. 8. It is advis- able to choose the Putting on the roof boards Was now in order, and type that will yy I found that this match your house ee } ul was going to be best. sefore put- 4 2 more of a problem ting the siding on, * eS es t el than an ordinary I covered the studs ea ore —i | gable roof would with a heavy build- = bay i be, as all of the 341

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342 corners over the hip rafters had to be mitered. This cut can be handled very well, however, if you follow the method I used. Starting from one side of the roof and at the bottom, lay the boards in the position shown by A, Fig. 12. After two or three boards have been nailed in place, saw the ends along the hip rafters even with the edge marked as indicated at B. This cut, of course, is at right an- gles to the face of the board, but follows the slant of the hip rafter. Continue the roofing all the way to the top in this man- ner and repeat the procedure on the op- posite side. After both sides are covered and the ends sawed, a similar arrange- ment may be used for the ends by butting the boards D against the sawed edges of the boards C. The ends of these boards are then sawed off flush with the face of — CASING, 3x44" 2x4'STuDS BUILDING PAPER \ DOOR 13x 40° 8-0" i CASING x4; POPULAR MECHANICS the boards that form the side covering. Matched material of a fair grade is best for roofing, although builders use just ordinary No. 2 boards, with the edges butted. Joints between the ends of roofing boards should come over a rafter, as otherwise there is danger of the board warping, tearing off the tongue, and mak- ing a hole in the roofing. The roofing boards should be started about 1% in. bevond the ends of the rafters so that water will be carried beyond the facing strips which are to cover the rafter ends. On my garage I used individual asphalt shingles of the same color as those on the house. I laid them 4 in. to the weather for the same reason, although I believe the general practice is to lav them with — WINDOW SASH, 2X2" — CASING, 3x4," - STUD, 2°x4” oo oe SIDING, 7x 6'\ 5 in. exposed. Roll roofing is cheaper but not so good looking or sérviceable, vet very satisfactory. Roofing of either kind is always laid fré6m the bottom up, so that the lap is on top. The roof on the garage is flat enough for you to stand on while working, but unnecessary walking on asphalt roofing should be avoided. as much of the gravel or slate is loosened or rubbed off, resulting in unsightly black spots on the roof, Putting on the trim, hanging the doors and windows, etc., is the pleasantest part of the job, or so it seemed to me at least. You are beginning to see the results, the structure looks like a garage and you can visualize it with a tidy workbench, shelves and cases in position, as well as a snug

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POPULAR MECHANICS 343 berth To! the “little old boat.” Perhaps | glad, too, that the rough part was finished. for | would rather work with the white pine in the doors and windows Figs. 13 show you just how to put on the telt a bit rhe series of detail drawing to 17, trim for the corners, cornice, windows and CLOOTS, They detail the garage exactly as | built it, with the exception that no win- dow is shown in the back wall. I put a window in the end toward the alley, but found it of so little use that I have omitted it in You own judgment about this. Fig. 13 is a section through a window, showing the sash, frame, casing and sill. the drawings. will use your The sizes and spacing of all these pieces are given in the sketch, The frames I made myself, buying only the sash ready-made and glazed. A 2 by 6-in. plank, planed as shown, makes a good sill, and as no machining was necessary, I used ordinary dimensioned lumber to make the rest of Fic.12 the frame. Ogee (OG) stops can be ob tained at any millyard for a small sum The large doors were purchased trom a mull that | could nice looking enough How ever. if your company as I did not think build doors that would be for the front of the ga rage. varage faces the tlley, it would be entirely possible for you to build the large doors with 34-'n. matched and beaded ceiling material. which would Fig. 14 place the stops, etc. be satisfactory. shows how to case the doorway,

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344 POPULAR

2X4’ STUDS -—~~

(hi Ay! S

The doors may be hinged or run on one of the various types of tracks on the mar- ket. I used a three-section door on a track for my garage and find it very satisfactory. This type has one of the doors hinged to one side of the opening and the other two hinged to the opposite side, and fold- ing against each other. The purpose of the track, which is on the outside, is to carry the weight of the center door. The “roll-around” type of door is also very convenient, as the three doors roll against the inside of one of the side walls. In some cases, however, this is an objection, as it makes that part of the wall space useless for any other purpose. Fig, 15 shows the method of placing the corner boards and is self-explanatory. It is customary to nail the boards together in a trough-shape before putting them up, MECHANICS as this will result in a tighter corner joint. Fig. 16 shows a section of the service door. JI used an ordinary five-panel pine door and rabbeted frame, which | pur- chased at the mill complete. This door

' orrset7 Fic.16 \ 3" v CASING, 5 X43

swings in. A lock is advisable. Around the rafter ends, | placed a facing strip, 41% in. wide, as shown in Fig. 17. The lower side of the rafters I also cased in with 5¢-in. matched and beaded material. My purpose in using so wide a facing strip was to give the effect of lowness, as my house is a bungalow. However, in the case of a two-story house, it may be advisable to secure the opposite effect, that is, one of height, by making the fac- ing strip narrower. If the overhanging ends of the rafters are ripped along a line level with the top of the plate notch, you can use a narrow strip in the same manner. Many garage builders omit the cornice and facing strip entirely and leave the rafter ends exposed. I do not believe this makes as nice-looking a garage. Not content with a facing strip, I placed

—" *

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POPULAR a box-type gutter completely around the garage, with downspouts at the ends toward the alley. This finishing touch completed the garage with the exception of painting, but it nearly finished me as well. I had so much trouble hanging and soldering the eaves trough that | am sure | would not attempt to put one up again, and unless you are experienced in that kind of work and have a tinner’s equip- ment, | advise you against it. For this have omitted it from the draw- though it is shown in the photo. Three coats of good-quality paint are required. The color scheme, of course, should be in harmony with your house so | will say nothing further about this. Electric lights are a great convenience in a garage and may be installed at very mall cost. The supply line can either be brought in from the house by means of overhead wires or, preferably, by laying a reason | Ings, lead-covered cable, which is inexpensive and can be purchased from two-wire most electrical dealers. The inside wiring I did with armored cable (BX) and the usual iron outlet boxes. The circuit (see Fig. 3, page 167, of the July issue) pro- vides for a trouble lamp, a light at the front of the car and over the workbench. All are controlled by a sin- the door. I convenient believe also one gle switch close to service find this and | it conforms with most city regulations. If you submit the accompanying draw- ings to your dealer, you can obtain an very estimate of the cost of material to con- struct this garage. > . ~ We Add to this an equal “ amount for your Ss labor, and you will SS have the approxi- ; mate cost of hav- ~ ing this garage RAFTER” >. built by a con- tractor. My total PLATE“ | cost for material, HI exclusive of the ce- stup —-—4)/ ment drive and ap- proach, $185,

MECHANICS

345 I have endeavored to make the direc- tions and drawings of the garage so simple and complete that you should have no difficulty in successfully constructing a well-built and serviceable garage: and if yoy find the pride and pleasure in it that I did, you will feel well repaid. Copperplating Small Tools Copperplating small hand tools is fre- quently desirable, as it provides an easy method of marking the tools for identifi cation of ownership. Besides, in many shops where soldering is done and where soldering acids are kept on hand, steel tools tarnish and rust very badly. <A light deposit of copper will prevent this. The apparatus and material required for this work are: a storage battery, fully charged, a handtul of copper sulphate (blue vit riol); a vessel of suitable shape and di- mensions for containing the article to be plated and a small piece of copper or some scrap copper wire Dissolve the copper The the solution is not important for this kind of 1 sulphate in water, strength of plating and a small handful of the crvstals will be enough for about 1 qt. of lo the the positive terminal of the battery fasten the water, wire connected to piece of copper or a short length of scrap copper wire twisted compact wad rhe article to be plated is connected to the into a negative terminal of the battery. Both the copper piece and the article are sup- itt ported over the container so. that eA they are completely immersed in the so- lution, keeping them separated from each other The length of time required for the plating operation varies according to the thickness of the plating desired. A few moments is suf- was ficient for a_ thin but this amount will T ~*~ protective coating. ° of ii} rr . ‘» vary greatly in dif- HTT ; FACING STRIP? l'o obtain uniform sei isco = HT Bis \ S'MATCHED & BEADED thickness, the arti- according to the tty \ ‘le S » cle: lin; OM \ sion cle must be clean material used, ~ Fic.17 and bright.

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346 POPULAR MECHANICS Locking Clamp for Pump Pipe Anyone who has attempted to raise a water pump with a length of pipe at- tached to it knows that it is a hard task. When the pipe is raised halft- way, the whole is top- heavy and al- most unman- ageable. Hence it fre- quently hap- pens that it is dropped back into the well. The drawing shows a sim- ple brace that catches the pipe at each lift, steadying it and prevent- ing it from dropping back. It is simply a strip of flat iron, about 1% ft. long. It is bent, and screwed to the well cover as indicated, the free end being rounded off to fit the pipe. After a lift has been taken, the clamp will automatically bind against the pipe and hold it until you have moved your hands for another lift—C. M. Wil- cox, Torrington, Conn.

Convenient Location for Auto Tool Box Having other use for the running boards of its business cars, one concern disposed of the tool boxes in a novel place, namely, between the frame members where they extend in front. The custom- ary running-board tool box, as a rule, will fit this space. It is located behind the bumper where it will not be easily dam- aged, and is, at the same time, readily accessible. The box is attached, at each end, by means of two bolts and wingnuts, the latter being inside of the box. The use of wingnuts is preferable to regular nuts as it may be necessary sometimes to remove the tool box in order to crank the car. As the box must be unlocked to remove the wingnuts, safety against theft is insured. This location for the box is especially convenient for tourists, as the running boards are loaded with other things, and the tool box forms a shelf in front on which a roll of baggage, the tent, or the like, may be packed. Forming Small Brass Tubes On one of the new radio devices sev- eral %4-in. brass tubes, 134 in. long and bent to a quarter circle, are used. As these must be produced quickly and at as low a cost as possible, the method shown in the illustration was employed with sat- isfactory results. The forming device con- sists of a punch, or forcing tool, for driv- ing the tubes through the forming-die hole. The upper part of the die is fitted to the lower part by tongues and grooves and the necessary dowel pins. The lower part is made in two pieces, each grooved to receive one-half of the tube. It is easy to mount the two blocks on a lathe face- plate, and cut the grooves with a round- end tool. The two parts are then fitted to- gether. By this method the tubes are bent without the slightest kinking and as fast as an operator can feed the cut pieces to the punch press. While a power press is used for this job, a hand-operated arbor press will do if the output needed is not large. The same method can be used for heavy- walled brass tubing up to % in. in diam- oan pg |

eter, and larger, if the bend is not too’ sharp, but thin-walled tubing, larger than 3% in., is likely to buckle.—-A. E. Granville, Cleveland, Ohio. @ Several turns of tape around the middle of a pulley face will prevent a belt from working away from the center.

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POPULAR Maintenance of Concrete Silos In the spring it is time to think of your ilo, which, possibly, is in need of repairs. Silage juices, if not cleaned off cement valls, will continue their destructive ac- tion on the cement. Small pinholes en- large rapidly during the hot summer days and in a short time the walls begin to crack and the silo will leak. To clean cement walls, use large-size wire brushes and hot water. It is advisable to dissolve about 1 Ib. of coarse salt to each pail of ater, which should be very hot. «This application will kill the destructive germs of the silage juices. After drying, it is a good idea to cement-wash the walls as smooth as possible.—G. i 8 Issakoff, Sioux City, Iowa, Wire Basket Helps Turn Eggs in Incubator Tray Turning the eggs in an incubator is a rather slow and tedious task. Many poul- trymen simplify and hasten the work by placing the egg trav on a convenient ta- ble and removing a row of eggs at one end so that the rest can be rolled in a toward that The turning is thus effected in a natural way and the eggs, which were removed, are replaced in the vacant end. While this method has its advantages, the removal of one row of mass side. eggs is slow and is accompanied by some danger of breakage. This can be elimi- nated by the use of a screen-wire basket, as shown in the illustration, one being provided for each tray. The basket is just large enough to accommodate a whole row of eggs.—G, E. Hendrickson, Argyle, Wis. Wire Basket Holding One Row: of Eggs Facilitates Egg-Turning Task in Incubators MECHANICS . 347 Convenient Scaffold Which Is Portable and Adjustable to Various Heights Adjustable Scaffold for Painters The adjustable scaffold shown in the drawing will be found useful by painters. It consists of two right-angle brackets made of 2 by 4-in. material, two pairs of diagonal nailed to each bracket to make it rigid and to permit the insertion of a 2 by 6-in. supporting plank, which in turn is prevented from slipping by means of stakes driven into the ground, as indicated. After the brackets been set up against the side of the house, planks can be laid over them. three pairs of supporting planks should be provided so that the scaffold can be set at various heights.—John Willis, Kans. braces being have Two or lobiason, India Ink in Fountain Pen India ink, used in fountain pens, dries out quickly and obstructs the flow through the feed line. This trouble can readily be remedied by plugging the small air holes in the cap. Moisten a bit of cotton batting with glycerine and push the wad into the end of the cap. After the pen has been filled with india ink, be sure to replace the cap as soon as you have finished writ- ing, and every time you use it, or the pre- caution will be of no avail.—J. E. Noble, Hollyburn, Can.

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Homemade Machine for Making Rope By HAROLD JACKSON | gues is a simple machine with which this block is moved by means of the you can make rope for halter ties, handle, the cranks will all turn with it straw slings, etc., from ordinary binder The head assembly is nailed to a bench twine. It is made from a few pieces of about 12 ft. long, or to the floor or hay 6-in. wood, some wire, about 3/16 in. in rack, if a bench is not available. diameter, and a screen-door spring. The The door spring is held by a nail driven drawing shows the construction of the into the bench some distance from the parts and the assembly head. If you wish to make a halter rope The head of the machine is made from that is to be 7 ft. long, fasten the spring two pieces of 6-in. wood, nailed together so that there will be $14 ft. between the to form a right angle, and braced as indi head and the near end of the spring. The cated. Three '4-in. holes are drilled in twisting of the strands shortens the fin the vertical piece about 4 in. apart and ished length of the rope considerably in the form of a triangle. Three cranks, It takes 36 strands of twine, 12 on each made of the wire and shaped as shown, = crank hook, to make a 5¢-in. rope. This are placed in the three holes. The cranks — is a good size for halters. All the strand should be about 3 in. long and all ex are then attached to the hook at the end actly alike in this respect. Make the crank — of the spring. Draw the strands tight so block next. This is another piece of wood, they will not sag, and the winding will 6-in. square, which is fitted with a wooden — then be easy. Now turn the crank slowly. handle. Three holes are drilled in it to This will twist the strands separately. coincide with those in the head and fit Twist them very tight, for the tighter they over the horizontal crank ends. When are, the stronger the rope will be. Keep the three strands separate until firmly twisted. Now unhook the spring and hold the strands with vour hand. You will find that they have a strong tendency to twist in your hand, Allow them to do so, but keep them taut enough to prevent sagging. The strands will then roll up tight, forming the finished rope. When finished, unhook the rope from Rope-Making Device Built from Wood, Heavy Wire, and a Screen-Door Spring, Will Be Found Useful to Any Farmer; Ordinary Binder Twine Is Used as Material and Can Be Twisted into Strong Rope 348

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POPULAR the head of will be If you are going to use the rope on a halter or want to put a ring or snap on one end, you can best do so by making a noose on the end. This may be done by running one end of the rope through the loops of the twine that were over the hooks on the machine. forms a neat connection. A ring should be pinched onto the other end to prevent unraveling. the machine and it ready for use. placed This hog Cementing Gear-Shift-Lever Ball After having several beautiful onyx gear-shift-lever balls stolen, the writer hit upon the idea of cementing one on to pre- vent its theft. Get about 6 oz. of fresh litharge, making sure that it is reasonably fresh, as it becomes “slacked” when ex- posed to the air and will not set. Toa teaspoonful of litharge add glycerine until the mixture reaches the consistency of a very thick cream, and apply this to. the threads both on the lever and in the ball. Then screw the ball down as tightly as possible. After a day or so, it will be im possible to remove the ball by hand.—G. T. Fowler, Bakersfield, Calif. Dividers with Bent Points for Marking Centers Ordinary straight-pointed dividers are often unsuitable for laving off hole cen- ters when there is an obstruction such shoulder or other raised part between the two points. To mark off center-to-center po- sitions under such conditions, make a pair of dividers with bent points, as shown. With these vou can get around most obstructions that would interfere with the ordinary tool. These dividers are made of flat metal with a caliper joint and are used as indicated. as a boss, Laying Off Measurements over Obstructions with Bent- Pointed Dividers MECHANICS 349 BUGGY AXLE~-~ BRACE —— “ BUGGY WHEEL =, Heavy Barrels Can Be Moved About Single-Handed by Means of This Truck Truck for Carrying Heavy Barrels rhe manager of a large oil station made a barrel-carrving truck that will prove of interest to garage and gas-station attend- ants and farmers g snerally, also to orchardists, illows one man to lift and convey a filled barrel. The truck consists of a U and gardeners, as it shaped axle made by welding sections of two buggy axles together, and suspension hooks that en When the handles are pushed down to the t10n eage the chines of the barrel. posi- BENT POINTS> most ient for moving the truck, the barrel will be raised 4 or 5 conven the Narrower similar construction can be used by in. above ground. ~ | trucks of ice-cream manufacturers, by making the suspen- hooks shorter so that they will en- sion gage with the han- dles of the ice- cream tubs and hold them upright. —G. E. Hendrick- son, Argyle, Wis.

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350 POPULAR MECHANICS — BATTERY CLIPS ~~. Tail Holder Made from Battery Clips and Wire Pre- vents Cow from Switching Preventing the Cow from Switching When being milked in the summer months, cows are often annoyed by flies and switch their tails to the discomfort of the milker. To avoid this trouble one dairyman provides his milkers with the tail holders shown. Each is made from a pair of battery clips, to which a length of wire is attached. In use, one clip is attached to the knee portion of the milker’s trou- sers, and, as he seats himself to do the milking, the other clip is attached to the brush of the cow’s tail_—G,. E. Hendrick- son, Argyle, Wis. Spring Center for the Lathe Many jobs that are held in the lathe chuck are first laid out in order to deter- mine the ex- act location of the part to be turned, bored or drilled. The spring center shown has been found of great help in locating the central point of the layout before closing the chuck jaws upon the work. The device is first TAILSTOCK SPINDLE entered into the center mark of the lay- out, while the work is held firmly up against the flanged face of the center holder. It is then approximately in the correct position to be held in the chuck, after which the center is moved out of the way. If a more accurate setting is desired, it can be accomplished by using an indicator—Chas, Homewood, Holly- wood, Calif. Jug Makes Good Bee Trap Swarming wild bees often settle in very inconvenient places about the farm build- ings, such as between partitions, under floors and other out-of-the way corners, where they can hardly be caught by ordi- nary methods. On a Wisconsin farm, a swarm collected between the lining and outside boxing of the barn, annoving both the farm folks and the live stock. At length, on the advice of a neighbor, the farmer suspended an open jug just be- neath the opening in the building where the bees had entered, doing this work after nightfall. A piece of cardboard, rolled up to form a tube, was inserted several inches into the mouth of the jug. By the follow- ing evening practically the entire swarm was trapped. The secret of the trick, it is claimed, lies in the fact that in the slightest breeze, a low hum, very similar to that made by in- dustrious bees at work in- side of the hive, is pro- duced in the open jug. The wild bees en- ter the jug to pilfer but cannot easily find their way out again —D. R. Van Horn, Lincoln, Nebr. Steam-Boiling Liquids in Vats In one workshop there are a number of large vats full of liquid, which must be kept boiling for several hours every day. The method formerly used to do this was to turn steam into each vat. As an experi- ment, the vats were fitted with light metal covers and just enough steam turned on

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POPULAR to keep the liquids boiling slowly. he result was satisfactory as it effected a saving of more than 20 per cent in steam. There are 1any factories where live steam still used to boil liquids in un- overed vats. Even when exhaust team is used in closed much of the steam can be saved nd used in some other way if all he vats are provided with covers, coils, especially if the vats are located n unheated rooms during the cold eason.—James E. Noble, West Vancouver, Can. Washing Photographic Prints in the Kitchen Sink efficient a photo-print washer should have two features: lhe water should be kept in mo- tion and the drain should be lo- cated at the bottom so that it will carry off the hypo, which is heavier than the bottom. lo be and hence settles at oth of these conditions are water met in an ordinary kitchen sink if ar ranged as shown in the illustration. All that is necessary to use is a length of hose and two short pieces of pipe. The hose is attached to the faucet and held toward one side, as indicated, by means of a cord tied to the other faucet. This makes the vater rotate freely in the sink. Remove the strainer from the drain and insert one of the pieces of pipe, which should fit into the drain snugly and rise 2 or 3 in, above the bottom of the sink, depending on the depth of water maintained during the washing. The other pipe, longer and of diameter, is notched in the bot- larger tom edge to permit the passage of water and placed over the first, as indicated. The water at the bottom, which con- tains the forced out by the pressure and the swirling motion of the whole body of water.—J. G. Pratt, Washington, D. C. hypo, is Kitchen Sink Makes a Good Print Washer for the Home Photographer Who Does His Own Work MECHANICS 351 ——$—— ees. | ) a Workmen Will Find = This Device Handy 7 for Lifting Heavy Work on the Bench Device for Lifting Heavy Work on Bench Often it is a rather difficult task to place a heavy piece of work in a vise sin work is of awk- lo facilitate the job handed, especially if the ward form. a special found useful. That shown herewith was made up of pipe and lifting tackle will be fittings, a lever of flat stock, a length of wire rope and a lock collar. The met hod of assembly is clearly shown, and it is rhe work is first placed on the bench, or on a truck of the height, and the hook are attached It is then used in the following way: same rope and lifted by means of the lever and swung over the vise. If necessary, the lever can be locked in this posi tion by the slotted collar as indicated. \fter the vise jaws are opened, the work can be let down with one hand on the lever, while, the vise is When through, the device with other, the tightened is stowed away

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Is This Your Home? QO" ena Hom regarding home building addressed to this magazine will be answered by The Architects mall House Service Bureau of the United States, Inc., controlled by the American Institute of Archi- nd indorsed by the United States department of commerce. Blueprints, specification forms, and ma- terial lists for the house shown here may be obtained from the Architects’ Small House Service Bureau for a small fee. If further information is desired, literature describing. the plan service and publications of The Architects’ Small House Service Bureau will be sent you upon request. A booklet entitled ‘50 Ways to Lower Home Service Costs,” illustrated by ten Bureau homes actually lived in and showing how as much as $1,000 can be saved on a home, may be obtained for 20c. |‘ the five-room bungalow is more ex- kitchen are arranged in order, one be- | tensively represented among the small hind the other, with dining alcove at the \ homes of this country than any other rear. There is not an inch of space wasted 3 type, evidently there must be something anywhere. Each room is well ventilated, ’ supplied by the house of this type to give has fine large windows with space for i it such wide popularity. The principal furniture. Convenience and economy have k reason for this no doubt is its economy in gone hand in hand. respect to building costs. The attic provides not only possibilities In this design every acknowledgement for extension in the way of an extra bed- has been made to the absolute require- room, but there is plenty of space for ments of economy, and vet the house has storage, that may remain unfinished for eood character from the exterior through the time being. Later on, as the family the proper massing of walls, openings grows, a bedroom may be arranged in tie and roof. This little house has the virtue attic as illustrated in the plan. of simplicity and vet, when it is finished The construction is of frame with ex- and set among pleasant surroundings terior finish of wide siding. Shingles or with flowers in the window boxes and © stucco could be used. A-lot of approxi- with vines upon the trellises, its attrac- mately thirty-five feet in width would be tiveness will be apparent to all. required. This house has been designed The plan is designed expertly so as to to face south or east. If views, prevailing make the most of what five rooms can winds, or other conditions make it more bring. The living room, dining room and desirable, it may be built reversed. 352