Popular Mechanics 1922-03: Vol 37 Iss 3

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POPULAR MECHANICS MAGAZINE WRITTEN SO YOU CAN UNDERSTAND IT ~ ; eS \ , x ™~ ’ —_ ‘ 7 ne ee oS ae

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Put Mle On Easy Street By O. H. Justus Not so very long ago it looked like I might plod along in the wage rut all my life. Today I’m living on “Easy, Street,’ * and when friends look over my property they say: ‘Justus, you’ve been lucky!’ ey see a big, busy auto repair shop, new stocks of tires, cars and trucks and scores of cars and customers coming and going. And they wonder how a wage earner could have got hold of such a business. Well, I didn’t do it by “luck,” brilliance or somebody else’s money. I did it by simply using the common sense every man has. And amy man who wants to can do as well or better. First, I made up my mind to TRY. Then I saw that the greatest demand for men, best pay and surest future were in keeping our millions of cars, trucks and tractors in repair. But I soon found out that becoming a mechanic by the old “experience”? system meant several more years of the grind. I also saw that the men who had learned that way were not getting anywhere, while the good jobs and big money were going to men with special training—men who knew the mechan- ical secrets of motors. ‘I don’t want to be a grease hound or a second-rate wrench twister,’ I said to myself. “I’m going to learn those secrets, too.”’ Henry J. Rahe made it possible. cause he can do the same for YOU. I read an advertisement about his quick, easy practical course in auto and tractor work in his big shop-schools—tearning with tools, not books, and from master instructors under Mr. Rahe’s personal super- vision. Largely out of curiosity, I mailed ‘‘the coupon in the corner.” And it turned out to be my ticket to “Easy Street.” A few days later I was on my way to one of the Rahe Schools Remember his name, be- Motor Secrets That — O. H. Justus and his at Parkersburg, W. Va. which I consider the ONLY big agency and repair shops schools. A few weeks later I was back home, a Rahe graduate —master of all the motor secrets that separate the $2-a-day laborer from the $40 to $100 a week of the real mechanic. Easy Rahe training had made me a free man for less money than a good Rahe-trained mechanic earns in three weeks. Since then I’ve never wanted for work pay as a mechanic soon enabled me which ALWAYS has had from a ahead of it. No job ever has My big own shoy ) an hour to open my week's to a month's work “stuck” me; none of my work has “fallen down.” I have employed mec hanics who had just “picked up” the trade—almost invariably to my sorrow. But I’ve never hired a Rahe-trained man who didn’t make good The only trouble was, I couldn’t keep them—they all went into business for themselves. And, so far as I know, every one of them is now on ‘‘Easy Street.” If you want to get somewhere, be your own boss and: make some real money, find one of those “coupons in the corner” and send it to Henry Rahe today. Then, if you use your wits, it will prove to be your ticket to “Easy Street,” too. I'm giving it to you straight. 1 KNOW. I] Want Men! Il’Il Pay Your Fare to Chicago, Cincinnati or Kansas City I want to help 500 ambitious men follow Justus to “Easy Street’’ in the next few months. YOU— regardless of your age or education—can get there easier than he did. Today the field is bigger, the demand for Rahe-trained men greater and the pay better. And you can get to my school nearest your ; home FREE OF CHARGE! [I'll pay your railroad f fare in full to my nearest school, no mattergwhere Z } you live. It’s going to be a BIG year for Rahe- \, trained men. Get started early! Just jump on a train for the nearest Rahe school. Every cent of your fare will be refunded the minute you enroll. (Read my 7-day guarantee.) Master Instructors Wonderful Shops ery instructor in my three schools is a MASTER a his business—trained by me and always under my direction. I keep constantly in touch with each school and see that things are done RIGHT. The Rahe shops are really wonderful. They contain PS oil fields. THOUSANDS of Rahe-trained make reports like this. Special Money-Saving Price I’ve always given as good a course and at as low a rice as that made by any reliable school, bar none Now, with schools in three locations—getting nearer men to my prospective students and increasing my ca- pacity—lI can reduce my price still further—and pay your railroad fare besides! Get my low tuition figures. You'll be pleasantly surprised. 7-Day Guarantee Try a Rahe School a week. Then, if you don't like it—if you don’t believe my methods will make you a competent auto and tractor mechanic—you can a and the 7 days’ training will cost you NOTH +. No other school offers this guarantee It's ogy INSURANCE of satisfaction. Don't forget—this will be a BIG year for Rahe-trained motor-maintenance engineers—thousands will be everything needed to make YOU, too, a MASTER of this big-money business. You don’t need “book learning’’ to succeed in this business—just a few weeks’ pleasant training on actual motors and cars. If you don't want to go into business for yourself, you can make REAL MONEY working for others. Bill Peace, one of my graduates, writes me that he’s making $250 @ month and expenses operating a tractor in the “Easy Stree and WILL right now. I've put 40, 000 men on et. do it for you if you'll simply you want to go. HENRY J. RAHE. needed. Get started QUICK! Send the coupon ora post ¢ ard and find out about the EASY Rahe way can to ‘Easy Street.”’ Do it today. +s me Yours for Tak. Say i by Xt quick success, a nd This Coupon NOW. HENRY J. RAHE, Dept. 2899 Please send me your big ilustrs ated FREE BOOK 1 and proof that you can put me on “Easy Street.” will start ‘ i ne bb6 66s cctdwdderisssibhosccrrvaceevescces I OR Ee er ee rere oe | WOW, ccc ccccsveccccscee State I Ee er eee l Address me at my school nearest your home ail “es ; wa! en Boul. and It Costs You Nothing to Get the PROOF The coupon will bring my big free book, with proof that Rahe training you to “Easy Street.’’ No cost—no obligation. Write me NOW. Address the nearest School—Dept. 2899 | Rahe iractor SCHOODS CHICAGO CINCINNATI KANSAS CITY 22nd and Oak Streets Ninth and Wainut Streets

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Popular Mechanics Tt. all REGISTERED IN U. S. PATENT OFFICE WRITTEN SO YOU CAN UNDERSTAND IT Ve 1. 37 MARCH, 1922 Flame-Throwing Machine Melts Snow Ve heavy drifts of snow, packed and hard to handle by any method f removal, are now being cleared away uch more easily and rapidly by demol- hing, instead of moving them. The now is melted by a stream of flame hrown at it in much the same manner it fire is quenched by a stream of wate: om a nozzle. The flame thrower also is a nozzle, which is connected to a pair f pipes, one leading to a boiler with team at 50 to 70-lb. pressure, and the ther to a tank of crude oil, which is kept it a temperature of about 90° F. by a coil | pipe connected to the boiler, the whole orming a unit mounted on a small motor truck. Behind the nozzle the steam pipe is spouted into the oil pipe, acting upon the oil in a manner similar to the action of the steam on the water of a boiler injector, thus forcing the oil out of the nozzle in a spray under high pressure. A kerosene torch, or other means, located beside the nozzle, ignites this oil spray, which consequently forms a stream of fire about nine feet long. In clearing away a snowdrift on a street, the flame is aimed high enough to do no damage to the pavement. As it bores a tunnel into the drift, the water drips onto the snow beneath, and helps to thaw it. Complete penetration of the drift demolishes it. steam —= Om hy FL AMEs BAFFLE- PLATE IGNITION BALL AND SOCKET OINT IK. Flame-Throwing Machine Used for Melting Heavy Hard-Packed Drifts of Snow: This is Melted Much More Rapidly Than It could be Loaded into Wagons and Moved Away. The Inset Shows the Machine in Sectional Elevation, with a Detail of the Nozzle, All Fully Explained by the Notations

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326 POPULAR CURVE-CUTTING KNIFE CUTS DIFFICULT SCROLLS EASILY A curve-cutting knife, cutting of stencil board, cloth, and other stiff Ping es for the also leather, oil- material, has its qf j j BLADE’ CUTTING EDGE MATERIAL it Small Knife Blade, Swiveled in Handle, Cuts These Intricate Scrolls with One Continuous Stroke with- out Twisting the Handle or Lifting the Blade swiveled in the caster, so that difficult cut rapidly with one con- tinuous stroke, and without lifting the blade from the material. This is laid on top of a piece of smooth and the cutting is all done by the blade edge. In time the point becomes dull, but this does not matter, as long as the edge is kept sharp. small pointed blade handle, like a scrolls can be glass, GOLD MEDAL COMMEMORATES DEFENDERS OF VERDUN In commemoration of the valorous de- fenders of Verdun, the United States has presented a gold medal as a gift from the American people, to that city. The medal, which is 4 in. in diameter, was designed by a sculptor of this country, and chosen This Gold Medal Which was Presented by the People of the United States to the City of Verdun, will be Placed in the Hotel de Ville in That Famous City MECHANICS from eight designs that were submitted in a contest. On one side is represented the Porte Chaussée, back of which are seen the ruins of Verdun. The other side portrays the heroic struggle between the armies, represented by the figures of two Titans in combat, and bears the inscrip tion, “Ils ne Passeront pas,” which means, ‘They shall Not Pass”—the famous watchword which inspired the French c¢ fenders during their year-long against the German attacks. resistanc: SERVICE OF WEATHER BUREAU SAVES LIVES AND PROPERTY The importance of the service of th: U. S. Weather Bureau is made very clea in its recently issued annual report. Th service, besides its direct economic ben efits, has been the means of saving many, lives, by forecasting great atmospheric disturbances, particularly since there h: been such a great increase in aviatio Many shipwrecks have, in the past, bee: avoided by timely warnings, and now similar service is furnished to all engaged in aeronautics. Another very important branch of this service is in connection with the protection of forests from fires and in their control after having been started. Highway weather service, a present confined to great highways, has been very valuable, and is now deemed essential wherever the traffic is heavy. Th« report contained the interesting an nouncement that 106 separate earthquak« shocks, strong enough to be felt, occurred during the last fiscal year. HUGE CANADIAN POWER PLANT COMPLETED AT NIAGARA Construction work, started in 1914, on a mammoth power project owned by) Canadian interests at Niagara Falls, was brought to a termina- tion recently, and water turned into the 12%4-mile Chippewa Queenston Canal. Completion of this channel raises the total water-power development at that place to more than 1,000,000 hp.. the latest addition being 650,000 hp., all of which has been accom- plished since 1895, at which time the first of the many hydroelec- tric stations located there began operation. Representatives of American and Canadian cities were present and assisted in the impressive opening ceremonies.

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AIR VIEWS OF MUSCLE SHOALS AND NITRATE PLANT Sanna Gea Northwest Corner of Alabama: Across the Shoals is Seen the Wilson Dam, Now About One-Third Finished, Which will Be 4,426 Feet Long, and 160 Feet Wide at the Base—the Largest Example of Monolithic Concrete Construction in the World r Airplane Photograph of Muscle Shoals, Located on the Tennessee River, near the Se Se, Looking East from Muscle Shoals, Air Photo of the Nitrate Plant, Which Is Now Idle, Which Cost $60,000,000 to Build and Equip: It Has a Yearly Capacity of 110,000 Ton Ammonium Nitrate. One of the Largest Phosphate-Rock Deposits in the United States I Adjacent to Muscle Shoals, Which Has a Potential Horsepower Next to That of Niagar

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POPULAR AIRPLANE STABILITY DEMONSTRATOR New and ingenious mechanical devices to aid in the study of the airplane in fight continue to be developed at the Through the Use of a Double Pendulum and a Record- ing Cylinder, the Stability of an Airplane in Flight is Shown Diagrammatically Langley Memorial Laboratory of the Na- tional Advisory Committee for Aeronau- tics. The latest is a device for illustrating airplane stability. The principal part of the machine is a double pendulum. At- tached to the lower end of the pendulum is a wheel which rests on a drum. When the drum is revolved by a small motor, the pendulum imitates the motions of an airplane in flight. This machine will greatly interest lecturers on aeronautics, and scientists and mathematicians who study the behavior of airplanes in labora- tories. There is a possibility that it may greatly assist in solving the problem of automatic stability. TONE PRODUCER FOR VIOLINS AND SIMILAR INSTRUMENTS It is said that a modern violin, of any ordinary make, can be converted into the equivalent of a Stradivarius, or other ,vio- lin of Italy’s golden days of string-instru- ment making, by the attachment to it of a By the Use of This Tone Producer It is Claimed Tones Equal to a Stradivarius can be Pro- duced on an Ordinary Violin MECHANICS newly invented tone producer. The de- vice, applicable to any kind of string in strument, is made of specially prepared wood, and is so constructed that it con- forms to the shape of the instrument to which it is attached. It fits to the under side of the top of a violin, and similarly on other string instruments. On an en larged scale, it may also be used on pianos and piano players. WRIST METER FOR MOTORISTS DETECTS ELECTRICAL FAULTS Motorists will appreciate a new wrist meter, which was designed to aid in the detection of battery, starter, and ignition troubles on a car. The meter fastens on the wrist, thus allowing the freedom of both hands in testing for grounds, short circuits, broken wires, weak batteries, etc. Included in the instrument is a small ammeter which is automatically protected against burning out, and a tiny buzzer to give audible indications in making cer- tain tests. A complete manual has been compiled for use in conjunction with the Electric ““Trouble-Shooter” That Fastens on the Oper- ator’s Wrist, Leaving Both Hands Free When Testing for Short Circuits and Other Troubles apparatus, giving in detail the faults to look for if the car does not run properly, so that one need not be an _ expert mechanic to locate trouble of an electrical nature quickly. PORTUGAL PRODUCES IMMENSE QUANTITY OF CORK Few people realize that Portugal pro- duces more cork than all other countries combined, the annual production being about 188,000,000 lb., harvested from more than one million acres of cork-oak trees. This is not its only industry, however, for Portugal produces more than 15,000,000 gal. of olive oil, besides employing more than 18,000 persons in the flour-milling industry.

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WIRELESS WAVES GUIDE AIR NAVIGATORS THROUGH NIGHT AND FOG Underground Cables Send Electric Waves Miles into Air Which Pilot Airplanes from Starting Point to Landing Place By H. A. LANE Y/osee interest has centered recent developments which proved to be of inesti- upon have French Loth, has perfected an Acting upon this principle, a inventor, W. A. mable value to the art of practical aeronautics in solving one of its most perplexing problems— that of making a safe and ready landing at night, in fogs, or under other ad- verse weather conditions. Navigation of the air is veing developed until it vill soon be as _ safely carried on as is that of he sea, which, through the invention of Earl C. Hanson, is made -com- paratively easy as far as pertains to narrow and + dangerous waterways. In brief, the Hanson method consists in submerging a cable in the proper course for a ship to follow in entering a harbor, and then sending an electrical current through it. The waves radiating from the cable are picked up by receiving instruments on the ship, and the intensity of these serves as a guide to the pilot, who sets his course over the cable. This Boat was Used in Making Experiments on the Seine River in Con- nection with the Magnetic-Cable Guide. Seen at the Extreme Ends of the Apparatus on the Stern The Receiving Frames are arrangement for with all types of flying craft. In the adoption of the elec- trical-cable idea, M. Loth differed to the extent that he buried it in the landing field. He had previously discovered, through personal investigations, that in the of aviation at sea, the “listening in the air directly use case zone’ over a sub two estab- merged cable, was nearly miles in height. Having lished this fact, the Frenchman equipped a plane with specially designed antennez, of the frame type, and conducted extensive ex- periments resulted in the present pr application to aeronautics In making demonstrated which ctical the tests, it was beyond a doubt, ate a ft could be guided just air cCratt could be guided just as effectually as seagoing vessels were controlled. When a current was sent through the buried cable, the electrical waves radiat ing therefrom impinged upon the receiving frames on the plane, and were then transmitted to re ceivers fastened to the ears of the pilot. Due to the character of the current and the instrument Listening to the Sounds Made by the Impinging of Electrical the Receiving Frames of a Large Airplane: The Speaking Tube Shown Terminates at the Pilot’s Station Waves upon used, there was produced listener’s ears a which has been singing likened

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330 POPULAR MECHANICS sound of a miniature siren. The sound would link all the aerodromes with elec was heard in little volume when the ma-_ tric cables for the guidance of air craft chine was barely within range of the at night, and in foggy or stormy weather. a : _. Then the pilot could follow his course with positive assurance, instead of having te grope his way through the night, or vainly endeavor to pierce an enveloping fog, as he strove to navigate his crait with its passengers and car go safely to its haven. FREAK LIGHTNING KILLS MAN AND HURTS WIFE Lightning is always playing queer tricks, but one of the most unusual occurrences happened in Michigan recently. During a s¢ vere electrical storm a woman Left: Horizontal Sociinting Receiving Peame. Right Gentine’ was standing at the kitchen doo: Horizontal and Vertical Oscillating Receiving Frame for Use ¢ 4 ex ch: / on Air Craft in Determining the Source of Electric Waves ol her home. Her hu band had just brought his team in from the waves, but as the center of the aerodrome field, and was standing at the door of the was approached, there followed a steady barn watching the storm. Suddenly there increase in tone, until, from a position was a bright flash of lightning, and the exactly over the cable, the notes became woman saw her husband fall and knew sharp and piercing. After passing beyond that he had been struck. She immediately the cable, the sound gradually decreased ran to him and seized his hands. As sh« until the plane traveled out of range. did so she received a shock so severe that Consequently it is apparent that the it rendered her unconscious. adaptation of the original marine idea for —— aviation, is going to ee mel. the BRICKS MAY BE BY-PRODUCT rapid evolution of the lighter-than-air machines. Particularly in the instance of OF OIL-SHALE INDUSTRY the passenger-carrying planes, which now operate upon regular schedules in Euro- pean countries, will it cause a greater feeling of security to those who wish to journey in this manner. The transit com- centage of lime, enough water being panies will no longer be obliged to ar- added to form a thick paste, which is then range the itinerary of their carriers so as__ pressed into the shape of bricks and dried to conform with the duration of daylight. in steam tunnels. It is claimed that they Tentative plans now under advisement are superior to clay bricks. The experiment of making bricks from the spent shale of the oil-shale mines of Scotland is now being tried. The finel) ground shale is mixed with a small per- Large ——— on Which are Installed Specially Designed Receiving Frames of the Horizontal Type Located at the Extreme Ends of the Lower Plane: The Latest Machines to be Fitted with Receiving Frames have These Placed within the Fuselage So That They are Completely Hidden

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SEVEN LOCOMOTIVES PULL LONG TEST TRAIN TO RIDGE OF CONTINENTAL DIVIDE By GEORGE F. PAUL Above Is a View of Part of the Cone TABER ' soar wags, | ABERNASHLADIO VASQUEZ,8,935 r CORONA, eso | -EAST JCT, 94 LEYDEN JCT,, Su VR_SPRINGS 1.OOO FT 5887 : 7 40 : : 1Q000 - 6.330 | ep 9.009 -DENVER, 5,'70 tinental Divide on the Denver and Salt Lake Railroad, Showing a Test Train, Composed of 34 Cars, Hauled by Seven Locomotives, Climbing the Divide. Lower Right: Sketch Showing, with Dotted Line, the Route of the Proposed Six-Mile Tunnel to Obviate the Neces- sity of Climbing the Divide. The Full Line Shows the Present Route of the Railroad with Its Numerous Sharp Curves. In the Sketch Above Is a Profile of the Railroad with Notations That Show the Relative Elevations and Grades between Denver and Craig ed aie BRAKE tests recently made with heavily loaded trains on the steep between Corona and Denver on the Denver and Salt Lake Railroad, may prove important in the development of the Yampa coal fields in Routt County. Up to the present it has been impossi- ble to haul many loaded cars at a time because of the heavy grades and numer- ous curves. As a matter of fact, 50 per of the mileage consists of curves. These curves vary from radii of 11,459 ft. to 359.3 ft. In addition, there are 58 tun- nels on the line, with an aggregate length of 24,763 ft. Of this number, about one- half are located on the eastern slope of the continental divide. Denver has an altitude of 5,170 ft. above sea level. For 13 miles west from Den- ver the track climbs af the rate of 1.65 - rades cent per cent. Then for 40 miles there is a rise of two per cent, and from there on the stiff climb of 12.41 miles to the summit, up a grade of four per cent. The summit has an elevation of 11,660 ft. This means that in the 65 miles there is a climb of 6,490 ft. On the western slope, conditions are practically the same, tor the road drops over a four-per-cent grade for 15 miles, then over a grade for four miles, followed by easier for 66 miles to Orestod. Then comes the climb over the hill at Topenas, followed by an easy descent to Craig The difficulties of handling freight over this line have made it practically impossi- ble to develop the great Yampa coal fields and yet there is an urgent need for the coal that could be produced in this region. The coal itself is bituminous and declared comes two-per-cent grades 1 rok

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POPULAR MECHANICS to be remarkably free from impurities. Furthermore, the mining end of the oper- ations can be readily cared for if the ship- ping problem can be solved. The haul over the four-per-cent grade is the bad feature. In the wintertime snowfall is always heavy from December on, and intense cold is all too often the rule. The summit rises about 1,500 ft. above the timber line. This means that snow blockades can become very serious. When the wintry gales are sweeping over the mountain tops at 60 miles an hour, filling the air with powdered snow, it takes only a few minutes to fill the cuts so that a train cannot operate. It has been proposed to do away en- tirely with these four-per-cent grades by the simple expedient of tunneling through the continental divide, but this in turn means a tunnel six miles in length, an undertaking not to be started on the spur of the moment. To negotiate these grades calls for two Consolidation and two Mallet locomotives to handle a train of 1,250 tons. These four locomotives have a tractive effort of 244,000 Ib. Because of the great risk of runaways on the descending grades, trains have been limited to this tonnage. For demonstration purposes on these grades, a train of 34 cars and weighing 2,431 tons was used. The cars were equipped with a special automatic straight air brake. The test was made to de- termine whether a train equal in length to the number of empty cars that one engine could haul back could be taken down the grade. The train pulled east out of Tabernash and up thé foot of the four-per-cent ascending grade, being pulled by three Mallets and two Consoli- dations, the five engines having a total tractive effort of 322,000 lb. At the foot of the heavier grade, two more Mallets were hooked on. These seven engines had a total tractive effort of 478,000 Ib. Before leaving Corona for the descent of the eastern slope and the run to Den- ver, all of the engines were removed but one, leaving the train to be handled by a single Consolidation locomotive. All of the triple valves were placed in graduated release position, the brake-pipe pressure raised to 100 lb., and the piston travel limited to 6in. One of the chief troubles of operation on this slope arises from hot wheels due to brake application. The 12.5 miles of the four-per-cent grade were cov- ered in 1 hour 40 minutes, or at the av- erage running rate of 7.5 miles an hour. Stops were made at Dixie Lake and An- telope for inspection. It was found that the temperature was very uniform, there being only a few cars in the train with wheel temperature slightly higher than the average of the others, but any wheel in the train could be touched with the fingers without discomfort. Officials who witnessed the demonstra tion declared that, with modernized equip ment, the tonnage down the grade could be doubled with safety, and operating ex- penses per ton-mile trimmed to half. Ii this proves true, far greater activities in the Yampa coal fields are assured. TENNIS ON “POGO STICKS” LATEST FAD IN SPORTS Tennis on “pogo sticks,” which is rapidly becoming a fad on thx Pacific coast, was first suggested by a Los Angeles sportsman. The “pogo stick” is a slender upright pole, with steps on opposite sides for the feet and a handle at the top. The base operates against a heavy spring contained in the stick. Balancing on the stick, one starts to hop, and the spring accelerates the bouncing so that each hop takes one two or three feet into the air. It requires con- siderable skill to handle the stick and, when tle maneuvers of ten- nis are attempted, falls are al- Playing Tennis on “Pogo Sticks’: nates Experts The Manipulation of a Racket in a Tennis Game, or the Handling of a Pogo Stick, Is Enough for Most People Separately; Their Combination Fasci- most unavoidable. Needless to say, the game furnishes plenty of amusement for those that are watching it.

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POPULAR MECHANICS Mormon Temple Which is Built in the Form of a Maltese Cross and nas been Designed on Strictly Straight Lines: Work has been under Way for Several Years on This Building, Which is Located on the Prairies of Alberta, Canada, Not Far from the United States Border MORMON TEMPLE IS DESIGNED ON STRAIGHT LINES Mormonism in Canada will center round the town of Cardston, in Alberta, where a large temple is being constructed hy people of this faith, Here has been the greatest gathering place of the immi- grants from Utah, who have established themselves in a land that is wonderfully fertile and promising. The temple, which will cost $1,000,000, is built in the form of a Maltese cross, and from a distance gives the impression of a huge pyramid, being 118 ft. square and more than 100 ft. in height. On closer inspection, however, the beauty of the structure becomes ap- parent, with its light-gray granite and concrete outer walls, 6 ft. in thickness, and its simple straight lines. \ decided contrast to the impressive severity of the exterior is found in the richness of the interior decorations .and paintings, which are the product of some of the foremost mural artists of America. The woodwork and paneling are espe- cially pleasing to the visitor, who, upon entering, finds himself first confronted by the baptistery. The principal feature of this is a mammoth marble font, which rests upon the backs of 12 life-sized oxen, representing the 12 tribes of Israel. Next are seen three special rooms, which have been designed for use in connection with the elaborate marriage ceremonies of cult. In the first of these, known as the “cre ation room,” are depicted upon the wall scenes representing the various phases of the creation of the world. A second. des ignated as the “garden room,” contains illustrations of the Garden of Eden, whil the third, termed the “world room,” po: trays conditions on the earth after the entry of discord. Above these three, i another room, luxuriously furnished, which is intended to suggest celestial glories, and which has three prayer com partments in it. The decorations of this “heavenly room” are in mahogany, onyx, and marble, the cost of which to nearly $100,000. This temple has been under construc tion for several years, and sometime dur- ing the summer of 1922, will be held the dedication services. After these rites, en trance to the edifice will be denied to all nonbelievers, and even to those of th: same religion who do not totally abstain from the use of tobacco, coffee, tea, and alcoholic stimulants, which abstinence is among the requirements of those desir- ing to be in good standing among the Mormons, according to their rules. amounted iron-clad

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POPULAR MECHANICS LIGHTWEIGHT KITCHEN TENT FOR MOTOR TOURISTS To meet the demand of moto: tourists, a special lightweight kitchen tent is being made. It is not intended as a weatherproof shelter, but as a _ protection against sun and insects when cooking and eating in the open. The flat roof and the lower part of the walls are made of light olive-drab drill, and the upper half of the walls of fine-mesh bobbinet, reinforced with drill. It occupies an 8 by 10-ft. space and is 6 ft. high. The entire weight, without the poles, is only 15 lb. and it folds into small com- Lightweight Kitchen Tent Specially Designed for Motorists as a pass so that it can be conveniently Protection against Sun and Insects When Cooking in the Open carried. TRACTOR HAS LEVELING ATTACHMENT FOR HILLSIDE Tractor owners have experienced con- and a front axle composed of three flexible siderable difficulty in operating their ma- bars which work on the parallelogram chines upon the hillsides, and to offset this principle in assuming the same position disadvantage, an Oregon man has con-_ as the rear wheels. A lever controls the adjusting mechanism, which is driven by power from the motor, and which can be operated while the tractor is in motion, or when it is sta- tionary. Due to this suc- cessful overcoming of the tractor’s serious draw- back, it is thought that the leveling attachment will be enthusiastically welcomed by all users ot agricultural, imple ments of this kind. Hillside Tractor with Leveling At- tachment as It Appears on an Incline, Showing Plainly the Side- plates, by Means of Which the Wheels are Raised or Lowered structed a leveling attach- ment for use with or- dinary implements of this type. The leveling is ac- complished by using ris- ime and lowering side eee plates which have stub Another View of the Hillside Tractor, Showing the Front Axle Which . : : 3 Works on the Parallelogram Principle in Maintaining axles, for the rear wheels, the Level of the Machine Constant

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RADIUM-BEARING MINERALS FOUND ON BRITISH COLUMBIA ISLANDS By FRANCIS DICKIE A! TER nine years of persistent search- fA ing in a great many parts of the rid. from South Africa to Alaska, H. E. Jeave, a mining engineer and prospector, ently discovered two radium-bearing r deposits on the islands of Valdez and neouver, off the coast of British Col- mbia. The story of the long hunt for area of radioactive rocks is in a way miniscent of those of the searchers for e Holy Grail, the fountain of youth, or philosopher’s stone, and other mythical jects, for, like them, Neave was actu- ed by an altruistic purpose. Though man of independent means, he con- 1ued his search for nine years, support- himself and family by at times work- small gold claims, come upon while arching for radium, or acting in the pacity of mining engineer. But always emost with him was the search for the ost precious mineral in the world, the ventieth-century won- ler-working radium, ich has in it nearly the powers that the ncients sought for in arious Ways. With the need of more of the precious 1etal foremost in his ind, Mr. Neave, nine ears ago, decided to devote his time to field vork in search of radio- active areas, for while there were plenty of nen experimenting with the medical and scien- tific possibilities of ra- dium, there was no one, as far as he could learn, making a systematic the search for the areas which undoubtedly must exist on the earth’s surface where this precious sub stance was hidden. So he started out. lle covered a good deal of South Africa. He came to North America and covered on foot the mountain regions of Idaho, Montana, and Washington, a great por- tion of the heart of British Columbia in the Rossland, Fort Steele, Vancouver, Sloacan, and adjoining regions, where the mineral might possibly be discovered. Following this, he prospected the west coast of Vancouver Island, one of the most difficult portions of the Pacific coast. He spent two years on Cook Peninsula, a desolate and uninhabited region, where landings have to be made through several miles of surf from a coasting steamer. In this region, while con- ducting his prospect- ing, he found that for some unknown reason the flora was unusual, particularly the hem- lock trees. Whole for- ests of these had their branches growing in an inverted way, that is, the branches were small at the trunk and 4H. E. Neave, the Dis- ; coverer of Radium on grew larger outward, British Columbia ending in natural Islands twigs and foliage. This was also true o' other and shrubbery. Here the wild-pea vine yielded peas as large as the cultivated variety, which were used sati factorily for food. Moving trees down the coast after two years of ineffectual search, lh discovered, in the fall of 1920, after nearly nine years of searching, a stretch of radioactive rocks on Tahsis] Inlet, Vancouver Island These he tested in two ways, by using an elec troscope, and also by taking photos, or radio graphs, two of the prin cipal tests for radium bearing strata. graphs are Radio- taken by A Scene on Vancouver Island: The House Is within a Few Yards of the Area Where Radium-Bearing Ore Deposits were Found utilizing the rays given off by the rocks to ob- tain photographs of coins, keys, etc., through such opaque substances as _ lightproof paper on a sensitized photographic plate At the time of making his discovery, Neave was not in possession of an elec troscope, a very sensitive instrument. But he was of an inventive turn of mind, and manufactured one which the purpose. This homemade electro scope consisted of a small glass jar with a rubber cork through which passed a metal rod. On the rod (and inside the bottle) a piece ‘of gold leaf was suspended by it center. The rod and gold leaf were charged with electricity generated by rub- bing a piece of ebonite with a silk hand kerchief, this causing the two ends « answered

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nf ool POPULAR gold leaf to fly apart; in a little time, the gold leaf slowly drops to its original posi- tion, but if a radioactive rock is brought near the instrument, the gold leaf drops suddenly. Though the discoverer found radio- active rocks covering a considerable area, he was still anxious to IECHANICS very few fields as yet in existence in the entire world, and the pitiful smallness si their output, the finding of any radium- bearing region is of great importance. It was in anticipation of exciting prospec- tors to hunt out this precious metal that the British Columbia Provincial Legisla ee. tive Assembly passed an locate another area, and guided by his knowledge of geology at once be- gan exploring near-by islands, with the result that in August, 1921, he made another find on Valdez Island at a place called Open Bay, an uninhabited stretch of logged-off land, where copper mining had formerly been car- ried on. The tests applied this time, in addition to using the electroscope, and making photographs by rays from the rocks, also consisted in using the scintil- loscope. posing Them This is a high-powered magni- tying glass mounted at the proper focus above a sensitized screen or plate of glass Photos of Key Ring and Key, Made by Ex- through Light-Proof against a Photographic Plate, to Rays from Radioactive Rocks act respecting the dis covery and conserva tion of radium. The act reads in part: “To the person proving to the satisfaction of th _Lieutenant-Governor in Council that he has dis covered radium within the Province, the Lieutenant-Governor in Council may pay a re ward not exceeding $5,000; and also make provision of a re tention for the crown of an interest, not exceeding fifty per cent, in all radium pro duced from such lands.” Previous to this strike, the island of Madagascar was the last place where radium was discovered. Paper, which is coated with zine sulphide. This WATER-POWER EXPANSION latter chemical has the property of be- IN OHIO RIVER BASIN coming luminous when struck by the Alpha ray or helium particles, which radio- Nowhere more than in the Ohio River active substances emit at the enormous’ basin are there great opportunities for velocity of 18,000 future expansion of miles a second. A ~~ a water power. Al good sample under orn? MAAGNIPYiNd GLASS though its drainage the instrumen ; area is only about shows ‘afoot “ROD monetary - ' parte Ran ” twinkling pin points SULPHUR ~~ the upper Missis of light. “CORK ane ee y sippi and Missouri, Satisfied with the S6Lass : its average wate area ol these two BOTTLE j SCINTILLOSCOPE flow is very much fields, Neave for- greater than thei: warded samples of /] ANOTHER FORM WITH combined flow. Th: the rock to Sir Ern ELECT ee Ohio River, with est Rutherford, the i about half the famous British ra- lf drainage area, has dium expert. The iF a water discharge mere analysis for . SCREEN» @ ff which is much more simple rocks costs than that of the St $250, and for com- Z| acy pm eB Lawrence River at plex ones much \ ve GOLD LEAF FLIES OPEN Ogdensburg, N. \ more. Sir Ernest's OWEN ELECTRIFIED These conditions “e reply, fully con- e sult from a greate: firmed his own The Homemade Electroscope Which the Discoverer rainfall in the Ohio experiments as to the highly radio- active nature of the minerals found. At this writing, of course, no estimate as to the new field’s productive possibili- ties can be ventured. Development work alone will reveal the amount of radium But with the which may be anticipated Used to Prove the Radioactivity of the Ore De- posits He had Located, and the Scintilloscope basin, and from the : general character o! the region. Added to this advantage ii water flow is the great number of excep tionally favorable sites for storage, many of which have already been located. Some of these give opportunity for ments de\ eloj

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Here is Shown Diagrammatically the Coal-Mining Machine Advancing into the Coal: All of the Operations of Cutting, Breaking, and Loading are Carried on at the Same Time COAL MINER NOW BECOMES OPERATING ENGINEER By EVERETT J. LOVETT WITH the rapid development of labor- saving methods, the coal miner is ing transformed into a keen-eyed oper- tor of a powerful machine which not ly mines and loads the coal, but does it a safer and more economical manner; ifer, because the coal is broken down thout the use of explosives which tend shatter the roof and make it danger- is, and more economical, because it pro- ices more lump coal and fewer fines, d does it more rapidly. One machine developed for this work the handle raises or lowers the ram. It is customary to leave 6 in. or more from thx top of the shears to the roof in order to prevent the shearing chains from inter- fering with the roof in handling the ma- chine. The forward feed of the machine is / ft. Thus, from each cut in a 6-ft. vein, is taken out a volume of coal 5 ft. wide, 6 ft. high and 6 ft. deep, or 180 cu ft., the equivalent of 714 tons. The time required for making the first cut in the face, ordinarily called the is about 20 minutes. “sumping cut,’ Coal-Mining Machine Makin “Sumping Cut’: Coal is Sheare on Both Sides and Undercut. A Powerful Ram Breaks Down the Coal onto a Conveyor consists of an undercut- ting frame with cutter chain, and a_ shearing frame on each side of the machine. In the under- cutting frame is a con- veyor. There is provided a powerful ram _ which breaks down the coal onto the conveyor. This ram can be directed at any height of the coal face. A slight touch on The machine is mounted in a pan and fed forward by means of a steel rope. When the cut been made, the machine is pulled back in the pan by means of a rope; then this rope is hooked over a sheave on the forward side of the machine and the eye fastened to a jack at the face of the opposite rib. By this means the machine is pulled sideways the width of the cut. This has A Storage Hopper with a Conveyor Receives the Broken Coal from the - Mining Machine and Loads It into the Mine Cars. By Using the Storage Hopper the Mining Machine may be Operated Continuously

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338 POPULAR requires about three minutes. The ma- chine is then ready to take another cut. Where the coal is tough and does not break down readily after being sheared on both sides and undercut, one or more hydraulic jacks are fitted in one of the shearing frames. When the machine has advanced into the coal a certain distance —20 or 30 in.—water is pumped into the jacks, which will exert an enormous pres- sure on the coal and crack it so that it makes easy work for the ram to bring it down. The machine can be used in combina- tion with a movable storage hopper pro- vided with a loading conveyor. By this CHICKENS ARE VACCINATED LIKE HUMAN BEINGS Chickens are now being made immune from chicken pox in the same way as human beings are protected from small- pox—by vaccination. At a number of ranches in California thousands of chick- ens have been treated in this manner. The COPYRIGHT, UNDERWOOD & eucennece One of Thousands of Chickens on a California Ranch That are Vaccinated for Protection against Chicken Pox vaccination is done exactly as in the human operation. The chickens have the advantage of not suffering any disfigure- ment from the resulting scar, for this is concealed .by their feathers. ANCIENT LAKE IN NEVADA THAT HAS DISAPPEARED Where there now remains only a com- paratively small body of water, called Pyramid Lake, in northwestern Nevada, there existed in a comparatively recent geological age a huge lake that covered an area of 8400 square miles, according to reports from the U. S. Geological MECHANICS system the machine operates continuously) during the time the loaded mine car is be- ing removed and replaced by an empty one. One great advantage of the use of the machine is the rapid development of the mines. Under the present system it may take as long as three years to develop enough entries and start sufficient work ing chambers to obtain a good output. This means that there is no return on the investment, which sometimes amounts to a million dollars, for the first three years. With these machines the cntries can be driven very rapidly, and the desired out- put can be obtained in a few months. Survey. This great lake, now almost com- pletely gone, was called by geologists Lake Lahontan, in honor of Baron La Hontan, one of the early explorers ot that region. Part of the old lake bed is now covered with sand dunes, forming a vast field of sand that is slowly travel ing eastward. This movement is irre sistible and has caused much trouble to the roads and telegraph poles in the southern part of Little Humboldt Valley CORNET-PLAYER ATTACHMENT ELIMINATES FINGERING The principle upon which the mechan- ical piano player operates has been ap- plied to the cornet, and a simple device has been developed which, attached to the instrument, will finger the keys to produce the proper tone. It is only nec- essary then for the performer to blow through the instrument as one would blow a trumpet. A knowledge of music is not required to operate the mechanical! cornet player. It is an English invention. The Strip of Perforated Paper is Fed Through Mechan- ically, Causing the Proper Keys to be Depressed

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POPULAR MECHANICS

Elaborate Set Built by a Motion-Picture Company for the Filming of a Beautiful Bubble Scene: In the Fore- ground can be Seen the Huge Iridescent Mass of Bubbles Which were Manufactured from Hundreds of Barrels of Soap, and in Which the Dancers are Performing MOVIE BALLET PERFORMS AMONG SOAP BUBBLES Beautiful scenes are common in the through it. The immediate transition motion-picture studios, and many me- into bubbles began, and these soon rose chanical effects are produced which fairly to a huge scintillating mass,in which the dazzle the eye of the onlooker. Asa cli- dancers performed, the whole presenting max to an un- - a scene of usually gor- —~ - fairylike splen-

geous “set” a director recent- : ’ ee = —__— ly called for a ti” @ Brazil will dance in the ' i i . have an inter- midst of soap i; ‘ = = national radio bubbles. <Ac- 7 central at Rio cordingly, since ; Se “Se de Janeiro, ac- a space 20 by ; | 4 cording to the 40 ft. had been } announcement designated to ; a) of recently com- be filled with pine , pleted plans, the frothy sub- rt P : ‘ eee which will be stance, a metal modeled after sieve of this ; os the gigantic size was fitted ~ ae | station at Port in the floor. A - : = ————__ Jefferson, L. I. soap. solution, Behind the Scenes, Showing the Soap Solution being Mixed in The new ven- made with 200 a Large Vat Preparatory to Piping It underneath the Sieve- like Stage Where It was Transformed into Bubbles ture will be bbl. of the constructed by product and mixed in the same man- a European radio company which will ner as plasterers prepare lime, was piped also build a substation at Para, in the to the porous floor, and steam forced northern part of the same country. dor.

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POPULAR AUTO SIGNAL HAS DISTINCTIVE AND PENETRATING LIGHTS Another peared automobile and is being signal has ap- marketed on the Pacific coast. It is mounted on the left side of the windshield, and is electri- cally operated by current from the car batteries. ‘An upper lens is provided with a Stationary light and re- volving col- lenses Pp Tro- ored which duce a dis- tinctive “at- tention” signal, visible j mile or more at night. Below is a direction sig- nal, visible from front and rear, the let- ters “R,” “L,” and “S” indicating right, left, and stop, respectively. The light is said to be remarkably penetrating and visible for a great distance, even through a dense fog. tor a FOR HIGH AND LOW TONES Violin construction is the desire to tones, and the controlled by produce the clearest of materials of which these instruments are made arealways selected with the greatest of care. A Bradford, Pa., man has in- troduceda violin, in which two kinds of woo d S used ; theory being that hard- wood vibrates faster and favors the higher tones, while softer wood has an opposite effect. His invention has two sections, with a hemlock front and maple are h i Ss MECHANICS back for the A and E-strings, and a pine front and cherry back for the D and G- strings. The bridge used has a broadei base than the ordinary type, so as to span the space which separates the two halves of the instrument. MILITARY RIFLE-RECOIL PAD PASSES SEVERE TESTS In tests, recently held at Fort Snelling, Minn., a new rifle-recoil pad proved highly satisfactory for use with military rifles. A recess in the stock of military rifles, to hold an oilcan and field cleaner opens through the butt plate and would be inaccessible with ordinary pads. This pad is either hinged to the stock or attached with clips and studs so that the recess re- mains acces- sible. It is made ofi sponge rub- ber, covered with leather. In the tests, two men fired, one using the pad. The second man was forced to quit after 250 rounds, becauss of a sore shoulder. The next day his shoulder was badly swollen, while the first man showed no bad effects. AMERICAN DRUG TRADE BOOMING IN BOMBAY The unrest in India is apparently not hurting some lines of business, for an American drug company, with offices in Bombay, reports that the sale of medi- cines in the country districts around that city is increasing so rapidly that it is impossible to fill all orders. The bus- iness is conducted on aggressive Ameri- can lines by extensive advertising and the missionary work of traveling agents, and possibly this more than counteracts any adverse conditions. The goods are shipped from Bombay cash on delivery.

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POPULAR MECHANICS Diagrammatic Representation of the Operation of Pontoons in Salvaging a Wrecked Vessel, Showing, from Lett to Right: Pontoons in Position above Wreck and Ready to be Lowered; Method of Dealing with Vessel Lying on Its Side; One Pontoon Lowered, and Other on Its Way Down to the Other Side of the Wrecked Vessel WRECKED VESSELS SALVAGED WITHOUT DIVERS Methods used, at present, for salvaging wrecked vessels, sunk in deep water, in- volve the employment of divers, whose powers of endurance are limited. A depth of about 200 ft. is considered the greatest in which divers can operate, but great hardship is experienced at much less depth. Thus, it has hitherto been con- sidered that vessels sunk in the high seas are unsalvageable. A great deal of study has been given to this subject in Eng- land, and an electromagnetic system of salvage has been evolved which has dem- onstrated the possibility of salvaging ves- sels at any depth without the use of divers. The sys- tem is based upon the use of submersible pontoons, to one side of which are at- tached power- ful electromag- nets. These pontoons work in conjunction with tugs, from which all electrical and air controls are directed. Each pontoon is sub- divided into a number of air- tight compart- ments, one of which is made habitable by means of maintaining atmospheric air Left: Both Pontoons in Position for Raising the Wrecked Vessel, to Which They are Electromagnetically Attached. Wrecked Vessel Raised, Ready to be Hauled Ashore pressure within it, independently of the depth of the water. Here the crew op erates, and in connection with it is a con- ning tower. The pontoons are sunk by filling the other compartments with water, and the crew has control over these com- partments, so that the pontoon can be tilted at any angle to make the best pos- sible contact with the sunken hull. The current is then turned into the electro- magnets, which cling to the wreck with sufficient force to move it. The wrecked hull is secured in this manner between two of these pontoons. By compressed air the water is blown out of the com- partments in the pontoon which then have a buoyan cy sufficient to rise to the sur- face. The pon toons are of va- rious sizes, suitable to the size of the ves- sel to be raised @ By a new sys- tem, the dis- covery of a Paris chemist, a hard and re- sistant metal- lurgical coke has been pro- duced from entirely unmixed coal from the Sarre basin. Right:

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342 POPULAR POWER PRESS PRINTS FROM COPPER OR STEEL PLATES Up-to-date plate printing has been done on hand-operated presses, but a machine has now been developed which performs An Automatic Power Press Which Performs All Oper- ations of Plate Printing Mechanically all the operations of plate printing auto- matically. The plate being set up, it is only necessary for the operator to feed in the stock and remove the finished work. Results are said to equal the finest handwork. MECHANICAL STOP SIGNAL SIMPLE AND PRACTICAL Stop signals are many and of various makes, but one of an extremely simple type, which has lately appeared, deserves U Left: Plate Which Fits over Tail Light. Lower Left: Shutter That Swings across Opening in Plate. Right: Plate with a = Containing Operat- ing Wire MECHANICS recognition. The accessory is fastened over the tail light, and has an opening in it large enough for the rays to shine through. An iron wire, to which tension is applied by pressure on the brake, causes a white-enameled shutter to swing across the aperture. Stamped out of this shutter, is the word “Stop,” in two-inch letters, which are covered with red silk. thus allowing them to be strikingly illu- minated at night, while in the daytime they are readily seen as a warning. ATTRACTIVE PARKING LAMP OF UNUSUAL DESIGN Every driver of an automobile knows the danger of leaving his car parked at night without showing lights, so a new parking light will be of interest, as it shows a light at front and rear, but uses very little current from the battery. Aside from the built-in appearance of the lamp, it has other attractive points. It uses only a 2-cp. 6 to 8-volt bulb, and in case it becomes necessary to replace a Parking Lamp with Two-Candlepower Bulb and Con- cealed Switch Which Shows a White Light Forward and a Red Light Rearward bulb, the cover of the lamp is snapped off, leaving the socket fully exposed. ELECTRIC POWER FOR SEATTLE FROM SKAGIT RIVER PLANT A great hydroelectric project on the upper Skagit River is being undertaken for the purpose of furnishing electricity for the city of Seattle, Wash. At a point where the river makes a great berd a tunnel is being driven through the solid hill, which, when completed, will carry water from the river to the turbines that drive the electric generators. The tunnel will be more than two miles long and will take two years to complete. A dam is to be constructed at the upper end of the tunnel to form a storage reservoir. The transmission line to Seattle will be over 100 miles long.

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POPULAR Operated by Cranes. MECHANICS Electric Map-Making Camera: At the Left Is the Huge Copyholder and at the Right Are the Bellows, Overhead Is the Rigid Tubular Framework Suspended by Springs to Avert Any Possible Vibration of the Various Units of the Camera MAMMOTH ELECTRIC CAMERA USED IN MAKING MAPS In the photographic laboratory of the Geological Survey, Department of the Interior, is located a camera of such huge dimensions that it has to be operated by small electric cranes. A rigid tubular-steel framework is suspended from the ceiling of a large room by springs, to avert any possible vibration of the various units of the camera which are hung from this frame. In one corner of the room is placed the plate holder, which is at all times stationary, and which extends through the wall into the adja- cent dark room. The bellows, terminat- ing in the lens and prism, are just in ront of the plate holder, as in ordinary isage, and are fastened to a carriage or crane for focusing purposes. The copy- holder, or frame, consists of two 4 by 6-it. plate glasses held in a steel frame, and ilso affixed to an electric crane for cen- tering the copy. Lenses of 31 and 42-in. tocal length are attached to a heavy brass means of plate and will produce any-size photo- graph accurately in this 7,000-lb. camera. The entire mechanism is electrically op- erated, and electrical contacts are ar- ranged according to a scale, so that the operator can easily determine when he has the proper focus with the gigantic outfit, by the lighting of signal lamps. The camera was built by the government for the sole purpose of reproducing maps. RADIO TO BE USED IN TRACING ‘LOST SHIPMENTS OF GOODS New uses for the radiotelegraph and telephone are being found every day, so it occasions no surprise to learn that an eastern company is planning to use this means of tracing shipments of goods lost in transit. In tracing strayed or stolen goods, the question of time is of vital importance, and this was one of the gov- erning reasons in adopting this means of communication. The plan, as outlined, contemplates the establishment of 35 radio plants in all parts of the country.

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344 POPULAR ITALIAN AIRPLANE ENGINE OF DIESEL TYPE A water-cooled Diesel engine of radial- cylinder type has recently been designed MECHANICS THAW SLEET FROM WIRES BY SHORT CIRCUIT Sleet storms periodically wreak havoc with electrical transmission lines, and as a remedy for this diffi- culty, a New England power company has suc- cessfully experimented with the problem of melt- ing the sleet from the conductors by short-cir- cuiting them, The “short” was placed on two par- allel three-phase circuits, strung for a distance of 8.3 miles at an average elevation of 2,000 ft., on which sleet coverings, 4 in. in diameter, had been experienced. Previously conducted tests had proved that 350 amperes at 6,000 volts, were needed to melt this cov- ering, and the necessary connections were made in a special bank of This Formidable Looking Airplane Engine is Designed to Operate on Heavy It Has Auxiliary Magneto and Carburetor for Fuel Oil. Starting with Gasoline in Italy. It is claimed that the engine will operate on any of the heavy fuel oils, and will develop 1 hp. for less than 2 Ib. of engine weight. It is equipped with magneto and carburetor for starting with gasoline, and also has a special device for reducing compression when starting. transformers to produce the desired current. The lines were then thawed alternately, so that serv- ice to the customers was delivered as usual, during the 15 hours required en- tirely to free the wires from ice. q@q When arrive suburban trains late, slips giving the time of arrival are presented to passengers upon request. Paris BIG DITCHER QUICKLY TURNS SWAMPS INTO FARMS The immense scale on which reclama- tion of swamp lands in Freeborn and Mower counties, in southern Minnesota, is carried on, means that, within a short time, great tracts will be added to the productive lands of that state. Work is being concentrated on a tract of 15,000 acres, which has been subdivided into eight units of from 1,000 to 3,000 acres each. Each unit is in turn subdivided into farms, most of which contain either 80 or 120 acres. The chief agent in this reclamation work is a wheel excavator of unusual de- sign and capacity. This 76-ton ditching machine crawls steadily ahead like some great land monster, and as it advances it digs a ditch that is 12 ft. wide on top and 7 ft. deep. A huge revolving wheel scoops out the dirt and a conveyor belt is kept busy carrying it out 20 ft. to the side, where it builds up a spoil bank. Working steadily with a crew of five men, the ma- chine, which is 65 ft. long over all and has a 110-hp. engine, can drive a ditch ahead at the rate of about a quarter of a mile in a working day. After the tile drains are laid, the sides of the ditches are thrown in to cover the tile. This work is done with a grading machine drawn by a tractor. Submains and laterals are added after the main drains have been laid. Then follows the building of bridges, roads, and groups of farm buildings. Work is done on a big scale, dozens of teams, workmen, and tractors being employed. Artesian wells are driven, fences built, and in a short time the marshlands have been changed into highly productive farms.

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The View Above Shows the Rear of the Big Ditch Digger at Work Excavat- ing Drain Trenches in Southern Minnesota Marsh- lands. It Makes a Ditch 12 Feet Wide at the Top and 7 Feet Deep, Deposit- ing the Excavated Dirt, by Means of a Conveyor, along the Side of the Ditch The Immense Excavator, Weighing 76 Tons and Equipped with a 110-Horsepower Engine, is Here Seen from the Front. It Is és Feet Long over All, and 33 Feet Wide; the Front Wheels Are 8 Feet High by 7 Feet Wide, and the Track-Layer Wheels in the Rear, 20 Feet Long by 8 Feet Wide. The Crew Eats and Sleeps in the House on Top of the Machine

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346 POPULAR NEW ILLUMINATION METER PORTABLE AND ACCURATE Until recently illumination meters have all been large and heavy, never really By Adjusting the Thumbscrew the Strength of Any Light may be Compared with the Strength of the Test Lamp IECHANICS portable. Now a light meter has been placed on the market which measures only 11 in. in length, but is entirely ac- curate. It is designed for measuring foot- candles, Lamberts, candles per square inch, candlepower, coefficients of reflec- tion, transmission factors, and for color matching. It is supplied in a compact carrying case. @ Nearly 4,500,000 acres of land have changed hands in Scotland since Novem- ber, 1918, this vast amount being prac- tically one-fourth of the entire country. About 800,000 acres were sold in 1920 alone, and in 1921 the total was more than 600,000. It is estimated that, alto- gether, land to the value of over $260,- 000,000 has been sold since the signing of the armistice. TESTING CHEMICAL ACTION UNDER GREAT PRESSURE Nitrates, the basis of explosives and fer- tilizers, can be produced chemically, and one step in the process is the formation of ammonia by combining hydrogen and nitrogen in proper proportions in the if catalyst developed by the Fixed Nitrogen Research Laboratory in Washington is said to be the most efficient yet dis- covered, and its behavior at various tem- peratures and pressures is now being . studied. For this purpose iH mae §6€6it:«6(is) placed in metal § cylinders called ‘“‘test- ing bombs,” where the chemical action takes place at different tem- peratures and at various pressures up to as much as 1,500 Ib. per square inch. @ Whenever you find that you wish to know more about any article in the magazine, write our Bureau of Informa- tion. Above: In the Metal Cylinders, Called ‘‘Testing Bombs,’’ the Action of the Catalyst is Studied at Various Temperatures and Pressures Right: The Recording Instru- ments on Which the Reactions are Observed and the Records Carefully Compiled presence of a catalyst. The quantity of am- monia that is produced depends, among other things, on the nature of the catalyst and upon the temperature and pressure at which the chemical action takes place. A

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Setting Up a Beacon on a Sand Bar on the Mississippi River: It Is One of 700 Similar “Aids” That have been Established along the 1,200-Mile Course of the River between St. Louis and New Orleans, to Direct Navigation of the Constantly Shifting Channel J). gerne TWAIN, in his “Life on the Mississippi,” devotes a number of pages to an almost interminable list of things that the river pilot of the old days ad to remember in order to stand a chance of avoiding disaster in the 1,200- mile run between St. Louis and New Orleans. So slight were a the shades of differenti- ’ ation between the marks that spelt danger or safety, that one is sur- prised, not to learn that the lower Mississippi is paved with an average of a half dozen wrecks to the mile, but that it was ever possible to car- ry on navigation at all. The almost prohibi- tive difficulties in the way of lighting and marking a channel that was here today and there tomorrow, made progress slow in the matter of safeguarding navigation on the lower Mississippi, and no com- prehensive system was worked out and put in- to operation until a number of years after = that scarcely were churned once a month by a dilapidated stern-wheeler were kept dredged, sounded, and marked, although the cost of the service must have been far and away in excess of the benefits accru- ing from it. But now, with the estab- lishment of Federal barge lines and rehabilitation of river traffic generally,the long chain of little beacons of what is called the Fifteenth Lighthouse District is finally begin- ning to justify its estab- lishment. I think I am _ well within the truth in stat- ing that none of the great navigable rivers of the world offers so baf- fling a lighting problem “Father of Waters” in its twisting, turning, caving-banked reaches from the mouth of the Missouri to the Gulf. I might mention parenthetically that all the old river pilots and skippers resent the use of the masculine gender in speaking of the great — river. Anything that , as does the the crest of traffic was Carrying a 12-Foot Aid Post up a 20-Foot changes its mind as past. Then, over a long interval during which river trade dwindled year by year, the lights were maintained with the characteristic thoroughness of the U. S. Lighthouse Service. Channels Bank, on Top of Which It is to be Erected often as does the lower Mississippi, they say, ought to be called she. And she they call it—when they aren’t calling it something worse. It is this capriciousness, this unstable- 347

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348 ness of mind (which the lower Mississippi gets from the Missouri, and which the latter, in turn, has got from the Yellow- stone) that makes the stretch of the river from St. Louis to New Orleans so hard to light effectively. A river that flows in front of a town one day and behind it the uext, cannot, obviously, be lighted with fixed beacons. Indeed, if changes of this description—which have, in several in- stances, had the effect of transplanting a town from Missouri to Illinois, or from Mississippi to Arkansas—were at all com- mon, it would be out of the question try- ing to light it at all. Since for the most part, however, changes of channel go on steadily but slowly, it has been possible to devise and main- tain a lighting sys- tem that is of incalculable assist- ance to the navi- gator of the great river. The lights on the lower Mississippi are officially re- ferred to as “aids POPULAR MECHANICS ever opened up regularly there) consists of a heavy post, about 12 tt. in height, deeply set in the ground and furnished with props, crossarms, stairway, and a bracket to receive the lamp. All parts of the structure are painted white. The lamps hold enough oil to keep them burn- ing continuously for 72 hours. A highly refined grade. of kerosene is used, fur- nished under specifications which require that it shall burn the full three days with- out depositing any soot upon the glass. In order to simplify the work of tending, the lamps burn in the daytime as well as at night, so that the principal thing to do is to refill them every third day. In my recent boat trip down the Mis- sissippi, I found that the aid, or light, at the mouth of the Missouri bore the number 686, and that the Westwego aid, five miles above the foot of Canal Street, New Or- leans, was numbered 1. As several of the to navigation.” The term light, or light- house, is reserved for a fixed beacon, the purpose of bers Marked .“‘A”’ Course of Line A. Part of Lower Mississippi: Num- Show Positions of Lights When Channel Follows Numbers Marked ‘‘B’’ Show Positions intervening aids bore the same num- ber, differentiated by the addition of ee which is to warn a ship away from a shoal or dangerous point. An aid, on the contrary, is al- most invariably in- tended to give a pilot an approxi- mate bearing for a When Channel Changes to Line B a letter, I think it probable that there are something over 700 aids scattered at irregular inter- vals along that 1,200-mile stretch of river. The manner in which the aids are course that will keep his steamer in the always narrow and winding channel. As this channel is constantly changing as the river rises and falls, it follows that the position of the aids will have to be shifted in order that they may help rather than mislead. The task of sounding out the channel and moving the aids to conform to it, is only one of the multifarious services performed by the government lighthouse tender that is kept in constant operation between the mouth of the Missouri and New Orleans. Two smaller tenders are operated on the Ohio and upper Mississippi, respectively, but the work of light tending is far less onerous than on the lower waters. The type of aid that is uniformly used on the Mississippi and Ohio (and on the lower Missouri in the event navigation is placed to help the pilot keep to his channel, will be plain from the accompanying diagram, which shows a 10-mile section of the lower Mis- sissippi. With the steamer channel fol- lowing the course indicated by the line A, the aids would be placed approximately as shown by the points marked 1A, 2A, 3A, etc. But if soundings made by the lighthouse tender at the end of the spring high water were to show that the channel had shifted to the course indicated by the dotted line B, then the position of the lights would be altered at the first oppor- tunity to conform roughly with the points marked 1B, 2B, 3B, etc. Immediately after making the fresh sounding and shift- ing the aids, the captain of the tender forwards a report descriptive of the new channel to the headquarters of the Fif-

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POPULAR MECHANICS teenth Lighthouse District, in St. Louis. Here this is manifolded and copies dis- patched to every master navigating a boat on the lower river. Tho 349 banks. The first year or two after it begins to appear above water, it is cov- ered with a thick growth of young wil- = latter immediately enters a summary of the fresh data at the proper point of his latest light list, where there are blank spaces left for remarks, changes, etc. The full report is kept ready to hand in the pilot house in the event difficulties develop in navigating the stretch covered by it. The language of these reports is in the purest “riverese,” a lingo of its own, and quite distinct from ordinary nautical jargon. A deep-sea sailor would be as much at a loss to get the sense of one at first reading as would the landlubber. With a little study, how- ever, the meaning of the strange phrases will become plain to a per- son of average intelli- gence, The word “towhead” is one that crops up often in Mississippi par- lance. It might best be defined, perhaps, as a cross between a sand bar and an island—an island in the making. It is usually formed in the first slack water below Men Returning to the “Oleander,” the Lighthouse Tender for the Mississippi, after having Shifted a Light on Account of a Change in the Course of the River Channel. lows. Later, cottonwood trees appear and choke out the willows. If a towhead augments, or holds its own long enough for the cotton- wood to attain a growth of 20 or 30 ft., it attains the dignity of, and is thencetorward called, al island. A “chute” is a narrow back channel be- hind an island. If there water enough, a steamer taking it may often save many miles of distance over the main channel. Directing a steamer down “the 1s a point where the river has cut heavily into its at _——— Light on Lower End of a “‘Towhead,” or Mississippi River Island in the Course of Formation Old Negro “Mammy” Who Tends the Aids Pecan Point, Arkansas shape of the bar,” or “the shape of the bank,” means that it should run fairly close to bar, or bank, and on a parallel course. The lighthouse tender Mississippi is the “Oleander.” It has been commanded from the day it was com missioned by Capt. Thomas Good, who has spent a long lifetime as pilot and mas- ter on the river. The duty of the “Olean der” is to cruise back and forth between St. Louis and New Orleans as fast as the exigencies of water, weather, and coaling permit, sounding out the channel, shifting, repairing, or replacing lights, and replen- ishing the supplies of the keepers. Under favorable conditions, it may average 100 miles a day on a downstream run, and perhaps 75 going up. A keeper may ten¢ from one to ten lights, though I only recal! one man with so many as the latter num for the lower ,

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350 POPULAR ber. If he has more than three or four lights, he will need a motorboat of some kind to get around to them. As all of the river fishermen have power boats, it is only to be expected that they should make up the bulk of the keepers. Those tend- ing only one or two lights are usually squatters cultivating a small patch of corn or cotton outside the levee. To support a family without other work, a keeper should have at least five or six lights, as the pay per light is not high. The duties of a keeper are: to keep the brush trimmed away in front of his light, so that it will always be in clear view from the channel; to replenish the oil and keep the wick trimmed and the light burn- ing day and night; to set back the light in case the bank below it is caving, and in such a way as to maintain approxi- mately its former bearing from the chan- nel; to report to St. Louis his needs far enough in advance to allow the “Olean- der” to be prepared to bring, or do, what is necessary on its next trip. If a light is carried away entirely, it is the duty of the keeper to set up a spare lantern on a post, or tree, and keep it burning until the “Oleander” comes along with the materials for a new installation. If, as IECHANICS occasionally happens through the tender being delayed, a keeper runs out of kero- sene, he is expected to buy enough to keep his lights going, at his own ex- pense, trusting to the government to reim- burse him later. As it is impossible to buy kerosene of anything approaching the high quality furnished him by the tender, a keeper confronted by an emergency of this kind is always in for a very trying period of smoky lights. Although running the whole gamut of the social scale from the old _ black “mammy” to an effete scion of British nobility (1 met both tending lights on the river), there is still to be found a remark- able esprit de corps among the keepers. Every effort is made by Captain Good to impress his keepers with the fact that the maintenance of their lights in all weathers, and in the face of every diffi- culty, is a matter of life and death im- portance. A number of men have lost their lives while endeavoring to save their lights in flood time, and of actual betray- als of trust there have been almost none. This is a wonderful showing, especially when one considers the strange odds and ends of humanity with whom it has been necessary to work. “WALKING” TRACTOR FOR USE ON PLOWED SOIL Front View of Tractor, Showing the Clearance be- tween the Bottom of the Engine and the Ground Loose, muddy, or sandy soil will not hinder the planting or cultivation of crops if a new “walking” tractor is used.. The tractor travels on “feet” which extend 12 in. be- low the frame, and these are set in an endless chain, so arranged that they take, or leave the ground in a perpendicular Side View of the Tractor, Which Illustrates How the Machine Has Four “Feet’’ on Each Side to Rest Upon Rear View of Tractor, Showing the Driver’s Seat and the Method of Lifting the' Feet from the Ground position. Thus oaly small holes, instead i of continuous : tracks, are left in 3 2 | the soft earth. The engine is mounted between the two rows of feet, and can be raised or low- ered to accommodate the height of the crop being cultivated, so that there is lit- tle chance of its receiving any damage.

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ite Te Successive Stages in the Opening of the Two-Part Parachute: First, the Outer Ring Opens, Checking the Fall; Second, the Inner Parachute Moves Up into Place; and Third, It Opens, Nearly Filling the Ring PARACHUTE IN TWO PARTS REDUCES SHOCKS The parachute holds the same relation to the air craft that the life preserver holds to Wwa- ter craft,and even when air travel has become reasonably safe, the parachute will continue to play its part in case a forced landing is nec- essary. As the speed of air travel increases, the strain placed upon the parachute in leaving the air craft becomes greater, and the danger of rupture of the fabric is also increased. To re- duce this hazard and to lessen the shock on the person using the para- chute, the two-part parachute has been test- ed in Germany. In making a jump, the outer parachute, which is merely a ring of fab- ' ! ; a Coteny, Parachute, Fitted with the Special rake, Shown at the Right ric, opens first, check- ing the speed of fall, whereupon the inner parachute then opens and the falling speed is reduced to not over 15 ft. per second. Another device des- tined to accomplish the same result, using the regular parachute, is in the form of a_ brake which is interposed be- tween the parachute and the jumper. When the initial pull on the para- chute is greater than the fabric will stand the cables take up the shock by unwinding, somewhat on the order of the spring counter weight. The tension of the brake may be ad- justed to compensate for the different weights of the jumpers. 351

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352 POPULAR COMBINED CASH DRAWER AND ADDING MACHINE A new combined cash drawer and add- ing machine occupies a distinct place among equipment of this type. A double roll is used, with a narrow strip of paper overlaid on a wide strip. Each item and total is printed on both strips. The wide strip rewinds, forming a permanent record. The narrow strip is torn off, after each transaction, as a customer’s receipt. Cash received and paid out is added or subtracted. The clerk or department, cash or charge, on account or paid out, are indicated. When the machine is un- locked, the rewind forms a record of the day’s business. The adding machine can be instantly detached for ordinary use. MECHANICS RADIO EQUIPMENT INSTALLED AS ELECTRIC-TRAIN FEATURE Entertainment will be provided for the passengers of the Chicago,,~North Shore, and Milwaukee Electric Railway, which has installed experimental radio equip ment on one of its trains. Serious difficulties arising from conditions not common to the ordinary wireless station, in the way of the trolley and motors, have been successfully overcome by the engineer for this company. During tests made recently, music for dancing was received, and conversations carried on between a station in Chicago and the swiftly moving train. The satisfactory results of the experiments have led the officials of the railroad to conside: equipping all the limited trains with wireless, and supplying each passenger with a receiver. These instruments will have a _ plug which can be inserted in a recep tacle beside the seat, so that those who choose may, while en route, listen to the radio news ot music now broadcast from many stations. be SPECIAL COPYRIGHT, UNDERWOOD & UNDERWOOD Electric Railway Train That was Equipped with a Wireless Outfit from Which Satisfactory Results were Obtained in All the Experiments Attempted. Above: Part of the Equipment Installed inside the Train

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POPULAR MECHANICS 353 Airplane View of North Island, Showing Its Broad Expanse of Almost Level Ground: Most Nearly Ideal Air-Craft Base in the World. This is Said to Be the Sunshiny Days, Gentle Winds, and Even Temperature Make This a Wonderful Location for Aeronautical Experimentation CLIMATIC CONDITIONS PUT FABULOUS VALUE ON LAND That the climatic conditions may justly be taken into account in fixing the value of a piece of land, was recently exempli- fed when the government purchased North Island, near San Diego, Calif. The island is to be used as a training station and air-craft base, its exceptional climate making it particularly suited for this pur- pose. Fifteen years ago North Island was merely a flat piece of land, worth probably $5,000. Today it is an ideal aviation base worth $5,000,000, this value being due primarily to the climatic conditions, which make it possible to carry on aeronautical experiments during the entire year, ob- taining maximum results with minimum risks. With the rapid advances that are being made in science, who can say what will be the value of land which today is worth only a nominal amount? TUBULAR-RIVET MACHINE HAS INGENIOUS TELLTALE the small size of the drill used in making small tubular rivets, close attention to the drilling machine has been necessary to prevent the passing through of spoiled work, in case the drill. should break. This has led to the development of a telltale that automatically inspects the rivets for proper drilling. The rivets being held in the V-slots, the drill and telltale are moved forward by a cam, and Because of if the rivet has not been properly drilled, the telltale pushes it into a compartment separate from the compartment for the properly drilled rivets. The telltale may be adjusted for different depths of drilling if necessary. ak Since — ee The Tubular-Rivet Machine: The Insert Shows the rill with the Telltale below It. Improperly Drilled Rivets are Rejected by the Telltale

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dod POPULAR FIRST-AID BOX INSTALLED ON BUSY STREET IN BERLIN To care for the injured in case of acci- dent, a first-aid box has been installed ’ Conveniently Placed near the Curb, This First-Aid Box Contains Essential Articles Which may be Needed in Case of Accident on one of the busy streets of Berlin, Germany. One compartment of the box contains a stretcher, while others contain bandages, drugs, and necessary accesso- ries for giving first aid. Advertising spaces are pr@ided on the outside of the box. \ road map to the nearest hospital seems to be the only thing lacking. LADIES’ HANDBAG CONTAINS CONVENIENT FLASHLIGHT European manufacturers of novelties have added to their extensive lists a flashlight which is fitted into a ladies’ hand- bag. On the outside of the bag, a nickel- Left: Handbag with Snap Open Exposing Reflector of Flashlight. Right: Another Form of Handbag with Snap Cover Closed MECHANICS plated snap cover, about % in. square, is placed, the opening of which discloses the reflector and also switches on the light. Inside of the article, a special com-: partment is provided for the accommoda- tion of the battery. TELESCOPE LONG IDLE NOW PUT TO USE Harvard College Observatory will soon put to use one of the largest telescopes in the world, which has been idle since its purchase 20 years ago, at which time it was declared unsuited for the work for which it was intended, because of certain features of construction. However, de- velopments in the science of astrophysics, or astronomy, during the intervening dec- ade, have served to find new fields for these instruments, so that now the 60-in. telescope can be utilized for special in- vestigations of the stars and planets. COAL CHUTE INCLOSED TO REDUCE DUST As a means of overcoming the dust and dirt nuisance attendant upon the unload- ing of slack coal, a Texas engineer has produced an inclosed chute. The chute, constructed of galvanized sheet steel and Inclosed Chute Placed in Position over a Manhole for the Purpose of Unloading Slack Coal with- out Producing the Usual Dust angle iron, has an opening at the tcp about 3 by 5 ft. square, tapers down to the size of an ordinary manhole at the bottom, and when in position, its height is the same as the common type of coal wagon. + @ According to recent estimates, 62,000,- 000 sq. yd. of concrete highway were laid during 1921, almost double the figure for the previous year.

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POPULAR MECHANICS — CONDEMNED U-BOAT HULLS CONVERTED INTO TANKSHIPS A soop example of German thriftiness is their utilization of their condemned submarines. Out of the hulls of two of these U-boats they have built a twin-screw motor tankship, called the ““Ostpreussen.” A sister ship, the “Oberschlesien,””’ which made its first trip with oil from Texas to Hamburg, encountered very bad weather, and proved its thorough seaworthiness. These ships were built at the Germania Yards at Kiel. They are the first attempts to convert U-boats into trading vessels. FISH LADDERS ON RIVER OBSTRUCTIONS IN CANADA Fish ladders are universal at dams and river obstructions in Canada, being compulsory by law. Therefore, they are comparatively more common there than in this country. A good example is one at Calgary, Alberta, at a dam on the Bow River. This ladder enables fish, in the spawning season, to surmount an otherwise im- passable obstacle on their way upstream to the glacial waters in the Rocky Mountains.

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356 POPULAR REPRODUCTION OF LAMP-POST IN ICE BY FREAK STORM During a recent storm bia River highway, near on the Colum- Portland, Ore., when rain froze as fast as it fell, some very freakish formations re- sulted. One particu- larly quaint, was at a sub- stantial con- crete lamp- post, high and very much ex- posed, where the wind blew so hard that it forced the rain away from the windward side of the post to the leeward, where it quickly froze. The accumu- lating frozen raindrops grew gradual- ly larger and larger until finally an ex- aggerated reproduction of the post was formed in ice and snow.

CHECK PROTECTOR ON PEN PREVENTS FORGERY Protection against the forgers is aided by the introduction of a new fountain pen, which has a _ check- protector attachment. The innovation consists of a small self-inking steel cut- ing wheel, which is built into the end of the pen, and exposed by unscrewing the cap. After the check is written, the cap is removed, and the red-inked cutter is activities of ' naire L a IM Fe Bore < Py nce aren Monn $ rer —# Top: aciiniien the “+7 of f Using the he Chats Protector. Bottom: Cap of Pen Removed, Show- ing Steel Cutting Wheel of Protector

ject to the MECHANICS drawn across the filled-in amount. The steel wheel perforates the paper, and the red ink flows into the perforations, thus rapidly providing an efficient safeguard against any alteration of the check. STATE LAWS ARE OVERRULED BY FOREIGN TREATIES A recent decision of the U. S. Supreme Court makes any state law relating to the holding of real estate by a foreigner sub- conditions of a treaty with the nation to which the foreigner belongs. The decision establishes the ruling that the California law that prohibits an Italian from holding property in that state is in- valid because it is in conflict with the treaty with Italy made in 1871. ELECTRIC WATER HEATER HAS HOT-WATER STORAGE TANK

For household use in the kitchen, bathroom, or laundry, a new electric water heater, in combi- nation with a 10- gal. tank, heats the water in the tank in 30 min- utes, and if nec- essary keeps the water hot for 24 hours or more. This is done by means of special insulation tween the double shell of the tank on the same prin- ciple as in the fire- less cooker. The heating elements are between these steel walls. be- NEW NATIONAL FOREST IN PENNSYLVANIA According to an announcement of the U. S. Forest Service the Allegheny Na- tional Forest is to be created on the head- waters of the Allegheny River in north- ern Pennsylvania. The tract will consist of some 400,000 acres, of which, it is_ex- pected, at least 50,000 acres will be ac- quired during the coming year. The bal- ance will be acquired as fast as appropri- ations are made by congress,

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CHAMPIONSHIP EXHIBITIONS OF SKI JUMPING This Is the Largest Ski- ‘Saaaion Slide in the World and is Located at Cdiooe, Alberta, in Canada. It is Constructed of Steel, upon the Roof of the Provincial Exhibition Building, and Rises 150 Feet in the Air. One of the Ski Jumpers can be Seen Just Leaving the Bottom of the Slide, Which Affords a Sheer samp of 150 Feet oa Oe a je* a ’ The Mammoth Steel Ski-Jumping Slide as It Appears from the Top of the Tall Structure: In the Foreground can be Seen a Jumper in Mid-Air. Around the Base of the Slide are Gathered Many Thousands of People Who Stand in the Snow and Bitter Cold to Watch the Championship Events, Which Always Arouse the Greatest Interest 3 |

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MINING METHODS APPLIED TO DAM CONSTRUCTION By S. R. WINTERS ee the construction of the Tieton dam of the Yakima project in Washington, the U. S. Reclamation Service will have added another noteworthy achievement to 230 ft. and a length along the crest of 900 ft., with a top width of 25 feet. A concrete corewall will extend through the full length of the dam and from its crest into the bedrock The nature of the bed- rock encountered will de- termine the depth to which the corewall will be extended, but in all cases it will be carried to a point where a solid footing is assured. Be- low the ground level, the corewall will be 5 ft. thick without reinforce- ment. Above the ground level, it will taper from 5 ft. at the base to 1 ft. at the crest, and will be heavily reinforced. Dur- ing the placing of this During the Construction of the Diversion Tunnel, a Temporary Power Plant was Installed Which, Taking Water through a Stave Pipe, Converted It into Electric Power to be Used for the Power Shovels and Rock Drills its already long list. The dam itself will be one of the largest earth dams in the United States, having a visible height of corewall the river is be- ing carried in a diversion tunnel, 2,200 ft. long and approximately 21 ft. in diameter, which will later be used as part of the water-control system. The excavation for and placing of the es Site of the Tieton Dam,Which will Rise to a Height of 230 Feet, Being One of the Highest Earth Dams in the United States: A Corewall of Concrete will Extend through the Center of the Dam for the Full Width of the Cajfion

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POPULAR

MECHANICS

Remodeled Power Shovel with Short Boom, Used for Loading Cars during the Construction of the 2,200-Foot Diversion Tunnel: corewall is one of the features of the work. In the river bed it will be neces- sary to excavate to a depth of approxi- mately 110 ft. in order to secure a proper foundation. The following method is being used: Three shafts are sunk from the surface of the ground into the bed- rock. At the bottom of each shaft a large sump is cut and a pump is installed. Drifts, 6 ft. high and 5 ft. wide, are then driven in both directions along the line of the corewall. The depth of these drifts in the bedrock depends on its nature and contour, but in no case is it less than 5 ft. \fter the lower drift is completed, a sec- ond drift is driven immediately above it. The material from this second drift is broken down into mine cars placed in the lower drift, and from there is taken to the shaft and hoisted to the surface. After the two drifts are completed, the lower drift is filled with concrete from cars run- ning in the second drift. <A third drift immediately above the second drift is then driven, and the process is repeated until the surface is reached. This method, known in mining as “stoping,” while un- usual in dam construction, has proved very satisfactory and has shown marked advantages over the open-trench method. This Tunnel is Driven through the Solid Ruck and Is Approximately 21 Feet in Diameter The embankment will be a hydraulic fill blanketed with rock, the upstream slope with a 3-to-l1 grade, and the downstream slope 2 to 1. Material will be brought from borrow pits to a central pool, where a pump will be installed. The fine clayey material will be punfped against the up- stream side of the corewall, while the fine sandy material will be placed against the downstream side. The completed dam will contain nearly 2,000,000 cu. yd. of material, and will create a reservoir hav ing a capacity of 202,500 acre-feet. AIRPLANE HELD MOTIONLESS BY WIND OF HIGH VELOCITY One of Mail Service was recently caught over Mineola ss i in a gale oft such violence that it was almost impossible to make any prog ress against the wind. By careful han dling, the airman ible to make a landing, nosing down in an almost per pendicular line with his engine running at full speed. the airplanes of the Air was @ Our Bureau of Information will answer all questions regarding articles in this magazine.

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POPULAR LIGHT-DENSITY CONTROL FOR FILM PRINTER In printing moving-picture positives it has been found that as many as 22 differ- ent degrees of light intensity may be nec- As Film is Printed, Control Keys in the Dial Change the Volume of Light as Necessary essary in a single reel to compensate for the different densities of the negative. Up to date it has been necessary for an op- erator to change the amount of light as required by a manual control, but this is now done by a control device which is mounted upon the disk and in which a different key is inserted for each neces- sary change of light. As each key comes into position, the light density is auto- matically changed by electrical control of the shutter. METAL OXIDATION PREVENTED BY ALUMINUM TREATMENT A process for preventing the surface oxidation of metals or alloys exposed to high temperatures has recently been pat- ented. The metal to be treated is placed in a retort filled with fine-powdered alumi- num and heated to redness. The alumi- num penetrates the surface of the metal, and when exposed to high temperatures after this treatment, the surface becomes coated with a layer of aluminum oxide, which prevents further oxidation of the metal beneath. MECHANICS REINDEER ACCLIMATIZED IN BAFFIN. LAND So complete has been the success of the acclimatization of reindeer in Alaska, that the Canadian government has been tempted to do the same thing in Baffin Land, that great barren island situated between Hudson Bay and Davis Strait. For this purpose herds of reindeer have been bought in Norway, and Laplanders have been engaged for a period of three years to take care of the animals. Six Lap families and their herds embarked, late last fall, at a northern Norwegian port, on a ship specially equipped for their transport. TIMESAVING DEVICE SPEEDS SALES OF RAILWAY TICKETS On systems such as the elevated rail- ways of large American cities, where a flat-rate fare exists for all destinations, passenger tickets are dispensed with, but in a system such as the underground rail- ways of London, Eng., where the fares vary with the destination, tickets are es- sential. In these conditions, every second saved in issuing tickets is of importance, and a new device is now being tried out that automatically dates the tickets, clips them, and at the same time registers the Timesaving Ticket-Selling Device being Tried Out on the Underground Railways of London, England: Tickets are Dated, Clipped, and Recorded Automati- cally, Before the Buyer Passes the Self-Registering Turnstile operation on a cyclometer, before allow- ing the buyer to pass a self-recording turnstile.

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oe es a en _— i en has 1is Seven-Room Bungalow, with all Modern Conveniences, was Built by the New Cement-‘Shooting” Process 1nd Has Walls Five and Six Inches in Thickness. The Surrounding Garden Wall Is Only Two Inches Thick and Has Seats Constructed into It in Such a Manner That the Whole Is One Solid Mass “SHOOTING” HOUSES FROM A “GUN’ By CLEVELAND GAINES “— LOOTING” houses out of a gun’ is the startling latest in concrete construction. is radical method of building vellings in short order, not only proved successful in the first o houses on which it was tried, it has shown itself to have a umber of advantages not pos- ed by other methods of con- truction. The gun itself consists a nozzlelike affair at the end ft a 3-in. hose. Dry concrete is put into a container and water forced through it. The mixture is thus made at the last moment be- fore it is applied. In building the first of the houses in this fashion, a one- ided framework of tar paper aot of , ind chicken x wire was erected. epee Brggn ‘ag Goat cad Wind w Fr — ‘/ aici [Iron reinforcing rods were placed igainst this and the concrete shot against thick was “shot” in this way, allowed to it with the use of the gun. A wall 2 in. dry, and the tar paper and chicken wir peeled off. The r sult was a solid concrete wall. Doors, window and plumbing were put in place and the wall shot around them. In similar fashion, ceilings floor, a fence around the yard and other parts of the house and yard were shot. Seats were shot into the wall at one place, deco- rative designs in another, and so on. The resulting house and yard was a complete home in one piece—a monolith. The second house built with the gun emploved wallboard in place of tar paper and "hicke ire : We he “T Exterior of the Bungalow, Showing One of the Outer Walls before chicken - We, Ww ith even better Shooting the Concrete Mixture against the Framework results, for the former was much 361

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362 more quickly put into place, ready for the gun work. [t is probable that this will be the method of forming the framework against which to shoot the concrete, which the inventors will finally adopt. With the gun method, the walls of a five-room bungalow can be com- pleted in two days. concrete is applied at a pressure of 30 lb. to the square inch, thus pack- ing it as no other force could do. Concrete im- properly mixed is auto- matically rejected—it does not stick—there- fore there is no chance of imperfect materials going into the house. The concrete is prac- tically mixed at the instant of application; thus there is no loss of strength in the concrete, due to partial drying before it applied. These are a few of the outstanding advantages of the shooting method of house erection. There are many others which must be obvious. It is rhe is Concrete this will eventually replace that of pouring that engineers method eae _ — _ Be ; f. : ~ ¢ vy st Somme Oe what. Se Garden of the Bungalow, Illustrating Some of the Ornamental Effects Obtained by Using the Cement-Shooting Process not necessary to mention: the great saving of time effected through building forms into the fact that there is no need of which to pour the concrete, nor the saving effected by hav- ing no waste of lumber, such as is the case where forms must be built of wood. There is numerable sibilities or vantages of the method, nor to draw upon the imagination to illustrate them. The few high lights men- tioned no tii pos- ad- do that sufficiently. There is no limit to the thickness of the structures shot detailing the in- POPULAR MECHANICS are of of the opinion applying concrete it in forms, as is com- mon at present. There seems no logical reason why it should not, and the many advantag: it make it ver) desirable that it should do Within a few years, all concrete con struction may be by the gun method. offers SO, NEW SUBMARINE CABLES OF GREAT CAPACITY Two new cables to bx laid during the year one between New Yor! and Germany and on between San Francisco and Japan, will have sending capacity at least six times greater than that of the present ca bles, if the claims of the engineers are fulfilled. One great difficulty in submarine cables has been the loss of cur- rent through leaks and faulty insulation Recent research has developed an alloy oi steel which, it is claimed, will prevent this seepage, and this new alloy is to be used as the insulating cover for the copper cor¢ in the ne Ww cables. Vith the seepag: loss reduced, the strength of the sending current by the gun— it is simply a case of shoot- into Which ing on more concrete until the desired thickness is attained. In the first house, one of the garden walls is 6 in. thick. 1s will be increased, and the speed of sending mes Built an Another View of the Bungalow Garden, Showing a Corner of the Surrounding Wall The Wall and Seat are Constructed in One Solid Mass Artistic sages will con sequently be much greater. @q That Panama Canal is being used to advantage was recently proved, when a new high ord for com- mercial ton- nage passing through was set. Eighteen merchant ves- the rec Seat. sels carrying cargo of more than 76,000 tons and yielding revenue of nearly $80,- 000 passed through in one day.

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POPULAR MECHANICS SNOW REQUIRED FOR SKIING TRANSPORTED BY TRAIN With one of the largest ski slides in the vorld, a structure 115 ft. high, built on top the highest hill at Fox CAMERA ATTACHMENT TAKES “SLOW-MOTION” PICTURES Formerly a specially built camera wa required tor taking “slow-motion” moy ver Grove, near Cary, S , and with a chute 360 long, everything was ready tor the most sen- itional kind of skiing at the National Ski Tour- nament — everything ex- cept the snow. The ab- sence of this quite indis- pensable element in the Right: Lens; ment to Right, Which Which Gears Up Speed to a Eight to One Interior of Cam- era, Showing the Chute Effect for Carrying Film. Below: Left, Spe- cial Mechanism for Car- rying the Film Past the i Arrange- the Crank is Attached and the Ratio of performance of skiing did not prove to be an in- superable obstacle to the the tourna- ment. The Norge Ski Club, which was in con- trol, followed the exam- le of Mohammed, and would not come to them, they went to the snow, situated in imple quantities at Bar- aboo, Wis. Thence they brought it by train— 10,000 loads of it —dis- playing their utter inde- pendence of the weather man. Although the slide was not in such perfect condition as it might have the tourney, which was held on January tended by 20,000 onlookers, one of the best ever staged in the history of ski sport. In order to make up for his remissness in the matter of the snow the weather man provided perfect atmos- pheric conditions, uccess oO! the snow been 22, and at > al « ” proved to be METAL END FOR GAS TUBING FITS ANY HOSE CONNECTION \ metal end for gas tubing that will fit any-size hose connection on any stov: hot plate, or fixture, without an) other adjus than tight . _ is composed of a oas tment screwing it 1 partly and with four longitudinal slot that make it compressible. rule is a hollow nut, threaded at one end and tapered at the other, so that when it is screwed on the ferrule, it compresses it and the hose end as tightly as desired on any gas connection, making it leak-proof thin metal ferrule, threaded, Over this fer- ing pictures, produced by running the film through the camera at high speed and normal speed. Now an available DY the use ol projecting it at attachment is which any motion-picture camer® wi! produce films at the rate of 128 to 200 ex per instead of 16 pi second, the normal rate. A special shutte ised, and a gear whic eight revolutions of the osures second, mechanism is rives to one of the crank. For cat om the lens, an nd the 1 him to and f1 chute is used, to withsta eliminate vi and static friction. Che device tached or removed in about on ind when removed, the camera bration lue to may lb used in the regular way without furth« 1 lange @ Popular Mechanics Magazine does not publish the name of maker or iny device described in its pages, but thi information is kept on file and will be furnished free by addressing our of Information. seller oO

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POPULAR MECHANICS AUXILIARY STARTING ENGINE FOR AIRPLANES airplane the propeller a large turning \nyone who has seen engine started by by hand knows what a strenuous and dan- gerous task this is. To make this danger- ous practice unnecessary, the Ss a This Auxiliary Engine Starts the Main Air- plane Engine by Pump- ing the Gasoline Mix- ture under Pressure into Each Cylinder Successively and | Firing Same auxiliary starting engine has been developed. It consists of a single-cylinder air-cooled engine mounted on the same shaft with a pump. The pump draws a rich mixture from the auxiliary car- buretor and forces it under pres- sure to the proper cylinder of the main engine, through a dis- tributor which is geared to the main-engine shaft. This causes the engine to start revolving, and, ignition being furnished from the auxiliary magneto, after one or two revolutions the engine begins to fire, and thereafter will be sup- plied with gasoline and spark from its own carburetor and mag- neto. “CONVERSATION” UNDERSTOOD BETWEEN BLIND AND DEAF Two blind and deaf girls who have attained world-wide fame, recently.carried on a “conversation” by placing their hands on the face and chest of the other, to interpret the vocal sound vibrations. Miss Willetta Huggins, of Janesville, Wis., and Miss Helen Keller were the principals in the demonstration, and each was easily able to understand the meaning of the other. Miss Huggins also possesses the peculiar ability of distinguishing colors by her highly developed sense of smell, as described in the January, 1922, issue of this magazine. @Subjecting glass in the soft state to a pressure of 3,000 lb. per square inch, to eliminate bubbles, is the basis of an ap- plication for a British patent. GARAGE DOOR OPENS AUTOMATICALLY BY WEIGHT OF CAR Quite a simple form of auto- matic garage door that is opened and closed by the action of a ca entering a garage or leaving it, i composed of a door, pivoted at the top, that folds horizontally at its center, and is raised above the top of the car by the depres sion of a hinged platform. There is a platform on each side of the doorsill for entry to, and exit from, the garage. The downward movement of the platform raises the door by means of pulleys and small guide wheels, and when the weight of the car is removed from both platforms, the raised Garage Door That is Automatically Opened by Weight of Car on Hinged Platforms, of Which One is Placed on Either Side of the Doorsill, and Closed When the Weight of the Car is Removed from Both Platforms door falls to a closed position by gravity, and automatically locks itself.

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POPULAR MECHANICS Above: Left, One of the Halves of the House Which was Cut in Two Parts, as It Appeared When Finished and Ready for Occupancy; Right, the Other Half of the Dwelling after having been Given a Covering of Tar Paper While Waiting for the Carpenters to Begin Remodeling. Below: The House Immediately After It had been Severed in Twain, with One of the Halves being Moved to a New Location. The Unusual Undertaking was Made Possible by the Substantial Manner n Which the Old Mansion was Originally Constructed TWO HOUSES MADE FROM ONE TO MEET HOUSE SHORTAGE An ingenious method of meeting the housing shortage was displayed when an architect and a contractor in Pittsfield, Mass., made two houses out of one. Like most communities, Pittsfield has been seriously affected by the lack of house con- struction during the past few years, and like many towns, especially in New Eng- land, it contains a number Of large houses the old mansions of some of the early wealthy families, built in the days when good material and good workmanshiy were inexpensive. When the owner of one of these residences died, it was closed up and offered for sale. Its 20 rooms, wit! the attendant expense for care and heat ing, were too much for any of the present- day families, and it remained empty Finally the plan of cutting it in two was hit upon. The halves were moved to new locations and finished as separate houses, Because of the hne construction, they were unusually de- of nine and ten rooms. sirable and easily sold, at a price which yielded the contractor a very profitable return on the investment. OIL-TESTING INSTRUMENT FOR AUTOMOBILE ENGINES hydromete water, has \n instrument, similar to a that measures the density of been specially designed for ascer- taining the condition of the lubri- cating oil in the crankcase automobile engine. On its ated stem it has a thi sleeve which can _ be lowered. On this horizontal spaces sively: rood, sleeve are denoted fair, poor, and dan- \ny convenient container, } ] succes verous. such as a pint measure, is first fille with new oil of the kind used in he crankcase Into this instrument -is placed, and sleeve is adjusted so that marked “new oil” is just surface. The instrument is then placed in the used oil to be tested, and the condition of the oil is indicated on the stem by the depth to which the instru- ment sinks. The “new-oil” line is on the sliding sleeve just be- low the space marked ss “oood

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366 POPULAR MECHANICS PNEUMATIC TIRES FOUND WELL RAILWAY SYSTEM OF MOROCCO INFLATED AFTER SIX In one case, at least, automobile tires have remained well inflated for six Racing Car Just after having been Dragged from a Lake Bottom Note Fully Inflated Tires Where It had Reposed for Six Months: Two machines racing on the ice on Lake Winnebago, at Oshkosh, Wis., when car suddenly broke through. The driver escaped, but the ma- chine went to the bottom. More than six months later, a reward of $50 was of- fered to anyone who located and recov- ered the machine. By dragging the lake it was found in 18 ft. of water. A diver fastened a chain to the axle and a tug dragged it ashore. The tires were found to be fully inflated. After six months on the bottom of the lake the machine was taken to the garage on the old air. months. were one SANITARY MILKING STOOL FOR MODERN DAIRYMAN In the modern dairy, with its sanitary conditions and white-clad attendants, the old-fashioned milker’s stool would be en- tirely out of place, but an aluminum stool which can be steril- ized is now available. A hole through the seat makes it possible for the milker to carry the stool over his arm and still have both of his hands free. MONTHS CHANGED TO NORMAL GAUGE Transportation in the French zone of Morocco has heretofore been accom- plished over narrow-gauge rail- ways, which were originally con structed for military purposes With the throwing open of thes« railroads for commerce, it was quickly discovered that the nar- row-gauge type was incapable of handling the constantly increa ing amount of traffic. Therefore it became necessary to build roads of normal gauge, and ac cordingly a program was started which will give the country ap- proximately 720 miles of track when completed. Coal-burning locomotives will be used in thx beginning, although electrifica tion of the system is under con sideration, as is the use of oil irning engines, should recent indication of an oil field in Morocco prove to be of substantial worth. 1 IMPROVED VENTILATOR COWLS PRESERVE SHIPS’ CARGOES An improved ventilator cowl has been tried out on several Pacific liners and found very satisfactory. The improve ment consists of a_ simple appliance on the inside of the mouth of the cowl ‘i \ which pre- 4 . Wh vents rain or spray, Or evel sea water! shipped in heavy weath er, from run ning down an open ventila tor. This allows uninterrupted ventila tion in the holds, with the result that there is no damage to the cargo from sweat, as is common with ordinary venti- lators that have to be closed in heavy weather. @ The Popular Mechanic’s Bureau of In- formation offers its free service to all readers of our magazine. Names and ad dresses of manufacturers and dealers in articles described, and any other details in our possession will be promptly fur- nished by addressing the Bureau.

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POPULAR REPRODUCING ORGANIC CELLS FROM INORGANIC SUBSTANCES Remarkably successful experiments have een made by a Mexican scientist in the rtificial reproduction of organic cells om inorganic substances. The biological mportance and general presence of fluoro- licates in cells and tissues have been cognized for some time. In his work of eproduction, the Mexican scientist placed drop of silicate under a thin plate to hich pressure was applied by placing on a weight of 50 lb. Under a contiguous late a drop of chloride of calcium was ibjected to pressure by a weight of 11 lb. These plates were covered by a glass vessel containing wet rags. The outside of the vessel was coated with plaster, as commonly done by chemists on retorts, to prevent the drying out of the solution. fter 24 hours the product was washed, colored, and mounted on balsam, when microscopic inspection showed it to have a remarkable likeness to living cells. LIGHTWEIGHT CASH REGISTER IS ADDING-CHECKING MACHINE A very compact little machine which combines the functions of a cash regis- ter, adding, and checking machine, has recently been invented. Used as a check- ing machine, it is light enough to be easily supported with orie hand while the keys are operated with the other hand, yet it is of substantial construction. There are no levers to manipulate, and there are less than 100 working parts, all told. The cash drawer is operated by a push button on one corner of the machine. Two Rows of Keys Control the Operations of This Combined Cash Register, Adding, and Checking Machine, Which Weighs Less Than Five Pounds MECHANICS 367 EIGHT GAMES TO BE PLAYED ON THE PHONOGRAPH Playing games on the phonograph is the latest form of amusement. A card- board disk is placed on the turntable. Playing Games by the New Method of Placing a Card board Disk on a Phonograph: Insert Shows Appearance of Disk and Indicator Used This disk has eight circles of letters, num- bers, colors, and so on, printed on it. A strip of cardboard, with a hole at one end, is placed over the center pin of the turn- table and its other end bent down to sup- port it clear of the disk. This strip has an indicator printed on it for each circle on the disk. The turntable and disk are revolved and stopped. The pro- gress according to directions and the signs pointed out by the indicator. gyames AUTOMOBILE-TIRE VALVES Dust caps for the tire valves of auto- mobiles are now being made of rubber. They are made so ,~ that they slip onto the valve stem tightly, without any screwing, and are as secure and dust-proof as a metal cap. Being made of rubber, they are, of course, rust-proof as well.

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*. — Panoramic View, Showing the Huge Dam with the Automobile Drive on Its Crest: The Lake Formed by the Im the Spillway at the 89-Foot Level, and Some Idea of the Size of the Steps may be Had by Comparison with the P MUCH WATCHED DAM PROVES SUCCESS By FRANK B. HOWE T will be remembered that some time to wait for a storm to see how the inno- ago there was chronicled the comple- tion of the Devil's Gate dam in southern California, a piece of engineering involv- ing several new and radical features, whose construction was examined with the greatest interest by engineering ex- perts. With the completion of the dam, there remained nothing to be done except The Outlet of the Flood-Control Tunnel is Located at Some Dis- tance down the Cafion in Order That the Released Waters Rush- ing Out may Not Undermine the Foundations of the Dam 868 vations would work out in practice. The test was more than the contractor bargained for. It so happened that the greatest flood southern California has had in 32 years came along to do the work In three days, a lake 242 miles long and three-quarters of a mile wide had formed behind the dam. Heretofore storm water had gone rushing down the Ar royo Seco, spreading destruction as they went, and causing great loss of life and property. In stead, this time the huge dam held the entire mass of water As an ordinary dam, it was a suc cess, but the greatest interest lay in the functioning of its several special features. At 89 ft. a large concrete spill way had been constructed around one end of the dam, to carry off overflow water and prevent a great accumulation of water from going clear over the dam, on top of which is an automobile boulevard. It had been expected that this spillway would rarely be needed. The unexpected storm, however, showed the extreme wisdom of

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, "2 ters Is Two and One-Half Miles Long and Three-Quarters of a Mile Wide. The Giant Stairway at the ~— Is Walking along It. The Spillway is Used Only as an Auxiliary Means of Controlling the Height of the Water he structure. The water rose ~ to the 89-ft. level on the third day ind started to gush over the spill- way in great quantities. Here is here the second feature of the dam came in. \n outlet tunnel had been built rom the bottom of the dam, not to the other side, but sufficiently ar down the cafion from the dam, to prevent its opening from causing a rush of water that might undermine the dam. As the water reached the top of the pillway, this outlet tunnel was opened and the water kept just under the spillway level by drain- The Spillway Acts Only as an Emergency Overflow in Case of a Sudden Rise of Water in the Storage Reservoir ing it from below. This water liberated from the outlet tunnel was hurled dozens of yards with terrific force; yet, being a long distance down the cafion, it did no damage to the dam, and per mitted control of the height of water behind the dam. At its height, a pressure of 12,000 Ib was exerted against each square foot of the dam. The Dam Presents a Curved Surface on the Upstream Side and ( ontrolling the waters in this Has the Appearance of a Concrete Wall along a Lake way has done aw ay tor the first ray

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870 POPULAR time with the peculiar problem with which California is confronted—that of rainfall coming in sudden and torrential quanti- ties. Coming in this way, the resultant waters have swept everything in their path, doing millions of dollars in damage. Heretofore no able to de- vise a means of handling this water. The basic principle of the Devil’s Gate one has been | City Hall of Philadelphia Illuminated for Faces of the Huge Clock are Seen on the Tower. Suilding, Illustrating the Lighting Arrangement. famous of their buildings, and the cul- mination of this feeling was the brilliant illuniinating of that structure. Eight batteries of floodlights, of 500-watt size, and totaling 300 lamps in_ all, installed in the form of were a square around CITY HALL OF PHILADELPHIA BRILLIANTLY ILLUMINATED Reverence is felt by the inhabitants of Philadelphia toward City Hall, the most New Year’s Celebration: Insert: Each Extreme Corner Has 38, and the Intermediate Points 37 Lamps MECHANICS dam is to catch this water and stop it; then to let it out gradually and in small quantities, thus permitting its disposal (in the ocean) without causing any damagy en route. The success of the dam in it greatest test—southern California’s great est flood—proves the unqualified succe of the system, and is a tribute to moder: engineering. the high tower, and the lighting effec first displayed on New Year’s Eve. Th: tower, sharply silhouetted against th night, served as a to guide th throngs of celebrators who always journey to City Hall Square, lently to watch the hug: and lofty clock toll off the last few minutes the old year, and to gree the new with loud a claim, thus at the time paying the old buil: ing added homage. beacon Salm WATER-POWER DE VELOPMENT IN SOUTHWESTERN STATES Among the many pro ects now under sideration in southwestern con t h« states for the development of wat power, one of specia interest is actually unde: way in Arizona. Phi building of a dam in tl Grand Cafion, above the intersection of Diamon Cafion, is being pro moted by a numb-« of copper companies. T! power developed approximately 150,00 hp., will be distribut: throughout the state, « pecially among the mi of the southwestern part which are ent on fuel oil and coal the cost of which is ce stantly increasing. At other project, unde consideration in southert California, is the construction of dams 1 Boulder and Black cafions that, beside power development, would impound so much water that millions of acres of no\ idle land could be made arable by irri gation. new depend Two Plan View of

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POPULAR MECHANICS The 10-Ton Tractor Pulling Two Eight-Foot Graders Abreast: More Even Working of the Road is Assured, as the Graders are More Inclined to Keep in Proper Relation to the Crown of the Road NOVEL ROAD-GRADING METHOD the idea of putting the two graders USES TWO GRADERS ABREAST abreast behind the tractor is novel. A 10-ton tractor pulling two 8-ft. graders That such a commonplace operation as_ has been covering an average of J miles the grading of dirt roads is susceptible of of road in a 10-hour day. The crown of improvement has been shown in Wiscon-- the road may be leveled off by adding a in. It was to be expected that the trac- small drag in the center, behind the tor would displace the four or six horses’ graders, in this way smoothing off the iormerly used for pulling the grader, but ridge that is usually left. ; 7 Showing How the Tractor Keeps to the Center of the Road: The Space between the Graders may be Varied to Suit the Width of the Road. The Cable is Used as a Towline in Crossing Narrow Bridges

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POPULAR MECHANICS Py a . ee | + #4e JAPANESE MOTOR FIRE ENGINE HAS NARROW ESCAPE ONLY the guard rail and the weight of the boiler in the rear saved this motor fire engine from a disastrous plunge into the river from the Watanabe bridge in the city of Osaka, Japan. Evidently the Japanese fire departments also believe in speed. SCENE PERFECTLY PORTRAYED IN NATURE’S MIRROR It is seldom that a pool of water is so absolutely motionless that the reflection of a rural scene on its bank is so perfect that in a photograph it is difficult to tell which is the landscape and which the re flection. A recent photo of this kind shows a rustic building, surrounded by trees in full foliage, mirrored in this pet fect way in a body of water beside them AMSTERDAM STOCK EXCHANGE SENDS WIRELESS REPORTS Stock-exchange reports in Amsterdam Holland, are sent at frequent interval throughout the day, to nearly 200 bank in that country, by means of wireless telephony. Thus is illustrated another practical use to which this method ot communication has been adapted, in the transmitting of the latest prices on th: stock market and other commercial info age on ere - mation. This, so far as known, is the first lis lot tine i ie kat ae Are instance of such usage of wireless in Indicate on Photo Which Is Which Europe.

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RAILROADS USE CUTTING MACHINES TO HARVEST ICE By F. L. CLARK 'T’HE Mississippi is a splendid source Pepin was resumed each spring consid- of ice for refrigeration uses of the erably earlier than navigation above it. railroads in the northern ites Mississippi Valley, par- ticularly for lines oper- ating in Wisconsin, Min- nesota, and Iowa. At Mc- Gregor,la., large amounts of ice are annually cut and shipped to various ice houses on the Chi- cago, Milwaukee, and St. Paul system. At Lake Pepin, ice-harvesting op- erations are carried on a large scale every winter for the Burling- ton company. * . | The lake is an unusual- —NNNNNnNmnmnaumnaapaa9n9ha9DO9MUT*w"XV?—" ee ly good place to harvest Elevating and Loading Machines for Conveying to Railroad Cars, on the HE al ao. Burlington, Ice Cut on Lake Pepin, in the Northern Mississippi Valley, natural ice because of its Which on Account of Its Size, Is a Good Place for Harvesting Ice size, the fine quality of ice which forms over it, and also because The word the railroads, river men, and it stays frozen so late in the winter that shippers waited for with utmost impa- operations may be carried on for a longer tience along in April was, “Ice has gone time than else- . out of Lake where on the Pepin.” ereat river. In Gas cutting early steam- ; machines there, hoating days, . . ' “aoe asat McGregor, hen lines of = have supplant- steamers were ; ed horse-drawn run from St. machines. They Paul in connec- are more effi- tion with the cient and eco- railroads which nomical, and 1 terminated on have this great +h > a- - , - sa . . e aon ' * ‘ nen © ne east bank One of the Gas Ice-Cutting Machines, Which have Supplanted advantage that of the Missis- Horse-Drawn Machines in the Northern Mississippi Valley: They jn open Ww inters. . “Yer are can be Used on Ice Too Thin to Bear the Weight of Heavy Teams a sippi, at Prairie when ice does du Chien, Wis., and Dunleith, Ill, navi- not freeze to great thickness, they can be gation of the Mississippi below Lake used with the ice not more than 8 or — aiden . ——= 1) in, thick, when it would be extremely dan- rerous, if not impossible, to use heavy teams. With elaborate elevat- ing gas-run machinery and long scaffolding sup- porting loading runways at the level of the top of freight cars, whole trains are loaded by the Burlington ice crews at once. The trains are sidetracked beside’ the runways with doors open, and as the cakes of ice are sent hurrying down Loading a Whole Train at a Time with Ice on the Burlington Railroad: ‘ . . awe ‘ hole The Train is Sidetracked alongside the Runway from Which the the runways, a nok Ice is Quickly Pushed through the Open Car Doors train 1S quickly filled.

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POPULAR MECHANICS RETURN OF CROWN PRINCE CELEBRATED BY JAPAN When the crown prince of Japan re- turned home after his recent six months’ trip through Lurope, he was _ received Pyrotechnical Cylinders, the Japan, That Furnished a works to Celebrate the Largest Ever Built in Brilliant Display of Fire- Return of the Crown Prince with a celebration which was without precedent in the history of the country. One of the striking features was a mag- nificent display of fireworks. Some of the ingle pieces cost as much as 300 yen. about $150, and the balls measured 2 ft. in diameter. The largest balls ever made before that time measured only 5 in. in diameter. When harged, these great balls expanded to a diameter of 4,851 ft.. in the air, and shed sufficient light to read a newspaper anywhere within a radius of four miles, it is said. Not only the prince. but also the emperor and empress, were cheered by the people, a which has occurred only twice before since the restoration of the present im- perial family. Traditional etiquette de- mands great formality and silence in the presence of the imperial family of Japan, but they seemed to enjoy this exception. dise demonstration qWlien you want anything and do not Bureau of Mechanics, Chi- know where to get it, write Information, Popular cago, MARINE-ENGINE CONDENSER OF NOVEL CONSTRUCTION Considerable attention has been at- tracted to a surface condenser for marine engines that has been invented in Bel- gium, and patented in several countries The object of the invention is to eliminate automatically all causes for engine break down due to defective feed water, pre- venting the entrance of salt water into the boilers, and maintaining in the con denser a constant state of cleanliness. The condenser has a steam chamber at on end connected to the engine exhaust, and another at the other end connected to the air pump. Between these two chambers in the main body of the condenser in which the water circulates, are series of pipes, divided into two or more separate groups, so that one group can be cut oft by a shut-off valve from the others, and can be attended to without requiring the stoppage of the engine. In connection with each of these groups is a specially designed salinometer—an instrument for measuring the quantity of salt that there may be in solution in the water of the condenser—that is electrically connected with an instrument board in the engine room, containing warning lamps that by ignition indicate a dangerous condition of the water. At intervals each of the sep- arate pipe groups can be shut off suc- cessively, and can have its water spaces cleaned out, so that no salt or grease will ever be there in sufficient quantities to do any harm. Thus the condenser can be kept running continuously, and at the same time be maintained in perfect con- dition. TO 412 DUMP Marine-Engine Condenser, Showing Cover Removed from One Group of Pipes, Which can be Cleaned While the Other Two Groups Remain in Operation: Inserts Are Self-Explanatory

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POPULAR MECHANICS

PACIFIC-COAST MOTOR BUS SEATS FORTY PASSENGERS T RANSPORTATION on the Pacific coast has been greatly facilitated by the introduction of large motor busses which have a seating capacity of 40 passengers. Five compartments, holding eight persons each, are built in the bus and are separated by glass partitions, so that parties of this number may journey in comparative privacy. The machines, besides being elegantly upholstered, are especially designed to insure comfortable riding, nd it is claimed that the average rate of fare is less than that charged for railroad travel. GERMAN PAPER-PULP MILL FIRST IN ARGENTINA — ventures are not always a suc- and illustrating the pioneering efforts of ss, but the first step in the introduction the Germans in South America. of paper-pulp making in Argen- — tina, seems to be _ progressing favorably. German interests are responsible for the undertaking, vhich is located in the Gran Chaco territory, near the Parana River, and 600 miles from Buenos \ires. <A single mill has been erected, that produces five tons of paper pulp per day, for which ready market is found in the ' bove-named city, thus assuring German Paper-Pulp Mill Recently Built in the Gran Chaco ; : ea rt] : “ Territory of Argentina, near the Parana River, and 600 Miles e prosperity of the enterprise, above Buenos Aires, Where the Entire Output is Sold

SWIVEL JOINT FOR HOSE bile gasoline stations can be avoided by AT GASOLINE STATIONS the use of a new swivel joint for the hose that allows it to be turned or twirled in Bending, cracking, and wearing out of any direction without injury. It is a com- hose at the curb connections of automo- mon ball-and-socket joint, with a specially designed seat that is kept pressed j igainst the ball by four springs. These are ad justable, and sufficient pressure can be maintained to prevent any leakage at the joint, without interfering with its flexibil ity. The swivel joint is attached to pump, and its socket slopes downwar as to act as a spout @ Electrical exports, which now agere- gate an approximate monthly total of $5,- 000,000.00, are largely composed of orders from the Orient, thus illustrating the steadily growing importance of that part of the world as a market for American Swivel Joint for Use in Connection with Pusgs at ‘ Gasoline Stations made electrical equipment.

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BUILDING SAFETY-DEPOSIT VAULTS By T. BENJAMIN FAUCETT HE safe-keeping of Liberty bonds has made almost everybody familiar with the general plan of safety-deposit boxes laid across them to reinforce the concrete. This makes a construction that is not only fireproof but practically proof a_i Sheet-Steel Forms for Pouring the Reinforced Concrete Floor on the Ground Level of an Addition to a New York City Bank Branch and bank-storage vaults. A burglar and fireproof place is necessary for such a bank department, but few know the type of construction required to obtain these qualities. Neither do we realize the vari- ous additional precautions and safeguards thrown around even the smallest deposit boxes in order that they may be protected. The building of an addition to a York City bank branch in a near-residence dis- trict offered exceptional opportunity to observe the method of fireproot- ing the = structur No wood or her infi mable material even the and doors being of thin metal, while the glass w: r a special kind that will re- sist terrific heat. The making of the concrete section, serving as ing for the basement vaults and as a floor for the ground-level deposit department, was especially interesting. The over which the concrete mixture is spread, are of thin sheet steel, strong enough to sustain the weight of the con- crete until it has hardened, and are fitted together in 3-ft. sections, that enable run- ning lengths of molds to be made for any size structure. Before the concrete mixture is poured over the molds, steel rods are fully New hame- = as used, windows a Cé il- Satetyv- metal molds, 376 against burglary as well because of the time nec- essary to drill through it But, even if the oute: walls and the concret: floor were destroyed by design or accident, the valuables within the vaults would be found intact within the well nigh heat-proof steel wal surrounding them on ey ery side. The entrance to these vaults is guarded by acylindrical steel door weighing several on though it is so accuratel\ the pusl of a finger will swing it in either direction. Fou time clocks are on the outer side of it and control the many 3-in. steel bolts that project from its circumference into the proper openings of the heavy steel facing At the close of business the big door are shut, the clocks set for opening time the next morning, and when the desig nated hour is reached the bolts are with drawn so that the vault can be entered Four clocks are used, so that in the un- balanced that —“ ‘Z "Th Pouring the Concrete on the Steel Molds of the Bank Floor above the Vaults at Ground Level: Reinforcing Rods are Seen at the Left. The Vaults are Protected by MHeat-Proof Steel Walls, as Well as by the Concrete likely event that three of them should stop, the fourth would yet withdraw the bolts at the proper time. Electric burglar alarms, directly connected with police headquarters, give quick notice of any tampering with doors or fixtures, while watchmen on the premises are also on constant guard. Bankers believe that pre- vention is better than cure.

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POPULAR MECHANICS , Left: Lightweight Steam Tractor Ready for Opera- tion. The Cleats on the Wheels Are of Angle Iron, and the Removable Belt Pulley is Shown above the Front Wheel. Right: The Engine; All Its Shafts, Piston Rods, Main Rods, and Crossheads Are of Heat-Treated Chrome-Nickel Steel LIGHTWEIGHT TRACTOR OPERATES BY STEAM Lightness and simplicity have been combined in a small steam tractor lately put on the market by a Cleveland, Ohio, concern. The machine weighs 5,500 Ib., has a rating of 15 to 30 hp., and possesses i speed range of from five miles per hour down to creeping. The steam generator, of water tubing, is sectionally constructed so that any tube can be removed and re- placed by a new one without disturbing the others. The firing system is of the vaporizing kind, having a positive auto- matic steam control which shuts off the fuel when 600-Ib. pressure is obtained, and starts it again when the pressure falls below that point. A _ two-cylinder double-acting engine with piston valves is used, which has a 4-in. bore with a 5-in. stroke. no electrical parts, carburetor, clutch, or gear shift, this trac- tor should be popular for its apparent reliability and economy. Possessing ITALY DEVELOPS SYNTHETIC INSULATING MATERIAL \s a result of the great activity in hydroelectric development in Italy, a new insulating material, made by chemical synthesis, has been developed. It is said to be ideal for insulating purposes. The Steam Generator to Which Water is Supplied by Plunger-Type Pumps, Driven from the Jackshaft: The Tanks Shown Have a Capacity of 60 Gallons, Enough to Operate the Machine for from Five to Ten Hours BASCULE BRIDGE IN OPENING ROLLS OVER BACKWARD Recently, at Gray’s Harbor, Wash., a bascule bridge of the rolling-lift which opens by rolling on a geared track, and facilitate this terbalanced around each ter of rotatio1 -when being imentally by a gasoline engine, continued rolling until it fell over backward. In the usual design of these bridges there is a stop provided directly nder the heavy concrete counterweight, but in this case this was absent, making the unprecedented accident possible. It was a single-leaf span of 110 ft., originally built for operation by hand. type— is completely coun- the cen- opened exper installed to side of rie wly

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POPULAR MECHANICS METAL ROSE TREE PRODUCED WITH WELDING TORCH Realistic in design and beautiful in ap- pearance is a metal rose tree recently pro- Ornamental Rose Tree Which Consists of Many Pieces of Metal Painstakingly Joined Together by an Oxyacetylene-Welding Mechanic Philadelphia artisan, duced by a welding me- chanic. The Steven Gavoorin, built the tree entirely of metal, except the “hearts” of the roses, which were repre- sented by colored electric lights. Piece hy piece the metallic sections were joined by the oxyacetylene torch, until when fin ished the whole presented a work that appeared almost genuine. OLD JINRIKISHA MODERNIZED WITH PNEUMATIC TIRES The most popular vehicle in the Far East is the jinrikisha. It is as popular there as the automobile is here, and it is apparently adopting some of the latter's refinements, for it is now being equipped with pneumatic tires. The ubiquitous Oriental “rikisha” is a two-wheeled ve- hicle, built somewhat on the lines of the obsolete hansom cab, with a coolie be tween the shafts who combines the work of the cab’s horse and its driver. The tires now used on the wheels are very like motorcycle tires, with similar inner tube and a flanged type of outer tire. REPORT SHOWS MINING TO BE HAZARDOUS OCCUPATION The report of the Bureau of Mines shows. that, during 1920, for every thou- sand persons employed in mines, quar ries, and metallurgical plants, 3.19 were killed and 221.22 injured. These figure do not include those killed or injured in blast furnaces. With all our safety de vices there seems to be still room for improvement. COAL-DUST BRIQUETTES SOLVE FRENCH RAILWAY PROBLEM Since the destruction of the coal mines in northern France, the shortage of loco motive fuel has been a serious handicap to the railways. The imported coal con tains much dust, making it unsatisfactory for use as locomotive fuel, but this dust is now utilized by making it into bri quettes, weighing from 6 to 20 lb. and containing as much as 92 per cent coal. SALVAGE LOCOMOTIVE PINNED TO RIVER BED BY PILING At the time of the Colorado floods in the spring of 1921, a bridge on the Bur- lington Railroad near Brush, Colo., was washed out, and a locomotive and bag- gage car went into the river. In order that traffic might be quickly resumed, a temporary wooden bridge was put in on the site of the washed-out structure. Later in the year it was decided to attempt to salvage the sunken locomotive. Pumps were installed, and the sand which had accumulated over the engine was pumped away. A diver then fastened a cable about the engine, and a 150-ton wrecking crane attempted to pull it out of the river, but without success. In- vestigation showed that two of the piles which had been driven to support the temporary bridge had passed through the engine and into the bed of the river, one pile passing through one of the driving wheels and one through the fire box. When these piles were disconnected from the bridge, the wrecking crane lifted the locomotive without further trouble.

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Right: The Broken Bridge with Baggage Car Hang- ing by ear Trucks. The Engine is Submerged between | the Baggage Car and the Bridge , Above: The Locomo- tive After It had been Pulled Up on the Bank. This | Shows the Two Piles of the Temporary Bridge, Which were Driven through the Locomotive, and Pinned It to the Bottom of the River Bed Above: The Diver Who Fas- tened the Cable around the Lo- comotive. His task was Rendered More Difficult by the Sand around the Locomotive 4 Above: After the Piles Which Heid the Locomotive own were Disconnected from the Temporary Bridge, the Wrecking Crane Made Short Work of J Getting the Locomotive Out of the River. One of "| the Piles can be Seen at the Extreme Right of the Picture

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350 POPULAR WORK OF ELEMENTS ON HULK IMITATED WITH TORCH When a motion-picture studio on the Pacific coast needed a weather-beaten old hulk of a wrecked ship for one of its pic- MECHANICS TONE OF NEW AMERICAN BELLS EQUALS OLD EUROPEAN ONES Hitherto the cause of the superiority of the tone of European bells, as compared with American, has been attributed to their greater age. It has Means Employed by a Motion-Picture Company to Counterfeit the Weather- An Acetylene-Torch Outfit was the New Lumber Beaten Hulk of a Wrecked Ship: Used to Burn Away and Char tur ; suitable type beach near by. Soa conceived the idea out of new lumber with an acetylene a was none of a ra) io found on the resourceful carpenter of building a “wreck” and turning a man torch loose on it. The torch worked short time as realistic a job plished as wind and waves could have done in years. { b and in a Was " ~¢+1 rectiv. accom- AMERICA SETS WORLD RECORD FOR ENDURANCE FLIGHT By remaining continuously in ‘the air for 26 hr. two American uirmen have set ; k's record for air plane flights. .\n all-metal monoplane of the J L-6 type was ised. The flight took place Dec. 29-30, 1921, at Mineola, L. I., under very adverse weather conditions. The only difficulty encountered, which finally caused the airmen to descend while they still had. sufficient fuel for more hours of flying, was the breaking of an oil pipe in the emergency oiling system. @ The U.S. 19 min. 35 sec Forest Service and the Cali- fornia State Automobile Association have agreed to codperate in preventing -the mutilation of road signs. The signs of the automobile association will be pro- tected by the forest rangers. now been proved by an ingenious American bell maker that the only effect of their greater age was to wear away the inner surface of the lip of the bell, and the © striki point of the clapper, u til much greater come into contact the bell is rung. Cons: quently, it has been simple matter to cast thi bell, and make the clap per, in forms which giv this greater contact su face from the beginning instead. of waiting 100 years for time to produce the same condition. This American manufacturer has proved that bells made in this manner pos sess the desired tonal quality after only month's ringing, instead of having to wait a century or two. area when THINNING OF CRANKCASE OIL SHOWN BY SIMPLE METER A meter which shows when the oil the crankcase of an automobile has lost its viscosity, in thin, is ex- pected to prove valuable to automobile owner;rs, Much dam- age is done by driving when the oil is in this state. Be- cause of vari- ations in driv- ing condi- tions, weather, and oils, mileage is an unsatisfactory gauge by which to change oil. The me- ter has a continuous stream of oil flowing across the dial, behind which is a tem- perature gauge. As the oil becomes thin ner it flows faster and rises on the tem- perature gauge. When it passes a certain mark, the driver knows that the oil must be changed. other words, become to serious

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POPULAR MECHANICS This Threshing Machine, Built from Parts of Seven Different Makes, Is Probably the Largest Ever Constructed. It is Used in the Wheat Fields in the Vicinity of Bottineau, North Dakota The Outfit, from Header to Blower, Measures 36 Feet in Length, and the Straw Travels over 60 Feet before being Discharged from the Blower. GIANT THRESHING MACHINE BUILT FROM SEVEN OTHERS Probably the largest threshing machine ever built is one constructed by J. J. Kro- gen, of Bottineau, N. D., from parts and attachments of seven different makes of eparators. It is so constructed that the grain is separated twice, and it will do 100-per-cent work even when crowded. The length of the outfit, from the folded header to the blower, is 36 ft., and the straw travels over 60 ft. before it comes out of the latter. Its capacity is 4,000 bu. of wheat a day, or 700 bu. of oats an hour. \ 110-hp. steam engine, with an 11-in. belt, is used for operating the machine. It requires a crew of 27 men, 21 being needed for pitching. WOODEN PICTURE PAINTED WITH NATURAL COLORS \ nove! picture has recently been com- pleted by a skilled woodworker in which all the coloring and variations of light and shade have been produced by the natural color of the various kinds of wood used. Thirty-seven different kinds of wood were employed, the completed pic- ture being 22 by 24 in. in size. The scene represents a boy starting on a fishing ex- pedition, accompanied by his dog, the background showing a landscape. It is Operated by a Crew of 27 Men ELECTRICAL CONTROL FOR GAS WATER-TANK HEATERS For lighting the gas under an ordinary tank water heater, an electric switch can be placed in the bathroom, kitchen, and laundry. This switch has “on” and “off” buttons and a pilot light. When the “on” button is pressed, a cir- cuit is closed. This operates a solenoid or magnet which turns on the gas under the heater. A small pilot light, burning all the time, ignites the The lever that opens the gas burner closes a switch on a circuit with the first pilot light, and a second switch in this circuit is closed by a small gas.

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35% POPULAR thermostat operated by the heater flame. When the pilot light goes on, the person who pressed the switch knows the gas is turned on and lighted. When the “off” button is pressed, the action is reversed. The thermostat can be set to shut off the heater automatically. GOVERNMENT INFORMATION BY RADIOTELEPHONE Recent advances in the art of wireless telephony make it appear highly probable that the government will adopt this means of broadcasting information relating to market and weather conditions. Since April 15, 1921, this information has been furnished the agricultural interests by means of radiotelegraphy, but the sim- plicity of the radiotelephone, and its univer- sal appeal, give it marked ad- vantages over the older method. Congress is being urged to establish a Bu- reau of Com- munication in the Post Office Department, and if this is done, radio- telephony will be the means adopted for broadcasting information of varying nature. The Post Office Department will draw upon the different government bu- reaus for infor- mation that will not only serve the interests of the farmer, but will be of ben- efit to the miner, rancher, fruit grower forester, and lumberman. will also be enlarged so that isolated points of the United States may be reached. There are at present eight radio stations, originally established in conjunc- tion with the transportation of mail by airplane, employed as distributing agen- The service Specially Designed Radiotelephone Transmitting Outfit for Broad- casting Weather and Market Reports, Occupies Small Space, and is Arranged for Either MECHANICS cies of market and weather reports. They are located in Washington, D. C., Ohio, Nebraska, Wyoming, and Nevada. In the event of the service being extended, new radiotelephone stations will be estab- lished in Georgia, Texas, California, Mon- tana, Illinois, and at one point in the New l°ngland states. Already, one specially designed radio- telephone transmitting outfit has been in- stalled, and regular schedules of trans- mission will be effective early this year. The apparatus itself deserves mention. In transmitting messages a current having a strength of 14 amperes is produced in the aerial, the normal sending-wave length being 1,160 meters. The voice modulation is said to be nearly perfect. Preliminary tests have succeeded in transmitting the voice in dis- tinct tones, as great a distance as 1,200 miles. The transmitte has three con trol switches so arranged that low-power in put may be used for local send ing, or high power for long distance send ing. Also, it is possible to uss either straight continuous- wave system or interrupted continuous wave system for sending radiotelegraph messages, as well as the con- tinuous-wave system for sending radio telephone mes sages, with an adjustment makirg Corvericwr, eneme 6 ones sible the Use Oo! four different wave lengths varying fron 800 meters to 2.000 meters. Four 250-watt “power” tubes are employed in conjunc tion with a 50-watt amplifier. The trans mitter is equipped with an operator's switch so constructed as to render pos sible the control of the transmitting outfit either locally or at a distance, with an pOs- Local or Remote Control

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POPULAR MECHANICS added interphone connection to remote control points. The transmitter is com- actly built and may be incased behind a yanel, the space requirements being only ’ by 3 by 2 ft. The motor generator is of the three-unit design. A _ direct-current iotor drives a plate-voltage generator at ne end, while a combined exciter and ament generator is located at the other nd. The plate generator supplies 2,000 Its through the use of two 1,000-volt rmatures, Up-to-date market and weather devel- pments have been transmitted by con- nuous-wave radiotelegraphy through the e of an are transmitter. With the in- tallation of a radiotelephone outfit in ‘al headquarters at Washington, ntually telephone transmitters will be talled at all of the broadcasting sta- ns under the supervision of the Post -e Department. SIMPLE FAIR-LEADER MADE FOR GUIDING CABLES Problems arise in the logging industry, effort to wind and unwind steel les without their becoming entangled, with conse- quent loss of much valu- able time. As a remedy for this difficulty, an Oregon man has made a fair-leader of simple con- which consists of a pair of heaves held in a disk that revolves in the direction of the strain placed upon it. The cable is inserted between the two pulleys, and they are always in _ line, regardless of what the angle of pull truction, may be. “SHOVEHA’PENNY” BOARD MAKES GAME POPULAR “Shoveha’penny” has, for many years, been intimately associated with taverns and similar places, in England, as “the poor man’s billiards.” Because it requires considerable skill, an attempt has been made recently to popularize the game. The method of scoring, with chalk, was very dirty, but a new board has been de- vised which eliminates this disadvantage. The game is played by shoving coins along a board, ruled off in sections, and the chalk was used to mark scores in the ooo proper sections. The new board has two rods along each side. Metal markers are attached to the inner rods, three to a sec- New “Shoveha’penny” Board in Use: In the Insert Is a Top View, Showing the Arrangement of the Rods and Markers tion, on each side. When not in use these markers rest on the outer rods. To mark a score, a marker is swung over onto the board, in the proper section. MECHANICAL TIRE PUMP OF SIMPLE DESIGN Patterned after the revolving-cylinder engine, a new tire pump has an eccentric shaft carried on a bracket hinged to the chassis. When the bracket is swung to bring the case into contact with the re volving flywheel, or other rotating part, air is drawn in through one end of the fixed eccentric shaft, and is distributed to the cylinders by air ports in the eccentric. The compressed air is delivered by other shaft, attached. air ports to the opposite end of the to which the air may be The pump is so constructed that case may be packed with grease. hose Revolving-Cylinder Tire Pump, Delivering Air through Fixed Eccentric Shaft to Which Air Hose may be Attached

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384 POPULAR FRENCH-DESIGNED MULTIPLANE HAS STRANGE APPEARANCE At first glance a new multiplane of French design seems like a step back- ward, as some of the very early exper- N [IECHANICS imental machines were of similar type, but the advantages of the multiplane and the narrow wing have long been recog- nized. The machine has 21 planes, or aerofoils, of only 6-in. chord, the span being only 14 ft. 9 in. These narrow aero- foils permit a construction which SPAR OF DURALUMIN TUBING would be impossible in wings of ordinary size, and under test, have proved very rigid and free from vibration, besides being fire- proof. Certain of the outer ele- ments are free to rotate on their central spar, and, by proper con- nection to the pilot’s control, can be made to act as do the ailerons of the standard airplane. Equipped with a 40-hp. motor, this multi plane has a maximum speed of 74 miles and a landing speed of only 25 miles an hour. @ Popular Mechanics Magazine does not publish the name of maker or seller of any device de- scribed in its pages, but this in French-Designed Multiplane of Small Span, with 21 Wings, Which Has a Landing Speed of Only 25 Miles. The Insert Shows the Wing Construction in Detail = formation is kept on file and will Narrow be furnished free by addressing our Bureau of Information. HARNESSING A TREACHEROUS MEXICAN RIVER Difficulties of railroading along the western coast of Mexico are strikingly shown by the experience of bridge engi- neers of the Southern Pacific Railroad Company of Mexico in trying to harness the Fuerte River. This is a treacherous stream in the state of Sinaloa, between Hermosillo and Culiacan. When it on its good behavior, it is a peaceful waterway, but during the flood periods it rises with startling rapidity, sweeping everything before it. When the railroad was river was spanned by a so-called tem- porary structure. In addition to 750 ft. of pile and timber trestle, 12 steel deck plate girders, 70 ft. long, were installed. These were placed on the south side of the river, over the deepest part of the channel where the current was strongest. This structure rose to an average height of 40 ft. above normal low water. This bridge did good service for sev- eral years. Then came a period of ex- cessively heavy rains. When the flood was at its peak, the tremendous current, rushing down at a height of nearly 35 ft. above normal low water, carried away four piers at the lower end of the bridge and dropped into the river five sets of is first built, the steel girders. Although some of these girders weighed as much as 70,000 Ib., they were carried downstream for a long distance by the resistless flood. Thereupon it was decided to replace the part of the bridge thus destroyed, in the meantime operating the trains on a temporary track and depressed trestle on a “shoofly” alinement. On the very day that the main bridge was put into service again, the river went on a rampage. Before sunset the raging flood had carried away three of the new piers and dropped four sets of girders The shoofly trestle was also a sufferer in this flood as it had been in previous flood times. When to these adverse physical con ditions is added the consideration that all common laborers, mechanics, clerks, fore- men, and master mechanics were native Mexicans, it can rerdily be seen that the special engineer who was in charge of the bridge work had his hands full when it was cecided to sink a pneumatic cais son. However, it was found the men were eager to master the principles and theory of what they were trying to do, and the experiment resulted in the work being completed in good shape. o!

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~~ > Sway Laborers were Kept Busy Try- ing to Prevent the Accumulation of Brush in Front of the Teme- The Weter Pressure Finally , Became Too Great for the Temporary Structure to Resist, and It Gave Way in the Center, Timbers and Rails being Piled Up like Jackstraws ee Above: High Water Delayed the |. | Construction of the Main-Line Bridge. Strongly Anchored Foundations Were Necessary to Withstand the Rush of Water 4 3 ~ res ———eeeeeEEe——EeEeee The Engine is Crossing the River on the — _ Temporary Track Which Is Now under | Water. The River at This Time was 1,200 fo 3 Feet Wide and from 12 to 15 Feet Deep } — - ee After the Temporary Track had Collapsed, the Timbers and Rails were Carried Downstream and Lodged against the Main Bridge, Which Caused the Water to Back Up to Such an Extent That the Pressure Became Too Great for the Bridge to Stand, and It, Too, was Washed Out 385

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POPULAR FIGS ARE RAPIDLY PICKED - USING WHEELED PLATFORM To use a three-wheeled platform for the purpose of picking figs, was the timely idea of a grower of that fruit, in order to MECHANICS SUPERCHARGING COMPRESSOR FOR AIRPLANE ENGINES At high altitudes, where the atmos- pheric pressure is considerably reduced, it is important to be able to maintain the air pressure at the car- Three-Wheeled Platform, Designed for the Purpose of Picking Figs, with Which Four Pickers can Strip a Tree of Its Fruit in Much Less Time Than wou!d Be Possible by Using Ladders harvest his crop quickly. Bicycle-type wheels were fastened to a wooden plat- form, which was enough to hold four pickers, and which was easily pushed around a tree or from tree to tree in much time than four ladders could have been handled. large less buretor intake so that it will be equivalent to the pressure at ground level, for which the engine of an airplane is designed. This is done by means of a supercharger in con- nection with an air com- pressor. As the pressures required are compara- tively low, it has been found possible to do this compression with a modi- fied form of the well known Root blower. This Root type of positive displacement blower, used as a compressor for su percharging airplane en gines, has been subjected to a great deal of study by the National Advi ——- sory Committee for Aero nautics at the laboratory at Langley) Field. Tests made there showed that, at normal engine speed and a pressure ratio equivalent to an altitude of 16,000 ft., the supercharged unit gave within 11 per cent of its ground-level power output. In nonsupercharged en gines there is a 50 or 55-per-cent power that altitude. researc! loss at ELECTRIC BRASS FURNACE HAS REVOLVING MOLD TABLE The advantages of pouring molten metal directly from the furnace into molds has led to the development of an fur- nace with a revolving table on which the molds are carried. An operator controls electrically the rotation of the mold table, and pours the molten metal as each mold is brought successively into position below the tapping spout. : : electric @ Names and addresses of manu- tacturers of articles described in this magazine will be furnished \ NA : ; | ia = free by our Bureau of Informa- tion. The Molds on the Revolving Table Are of Sufficient Capacity to Take the Output of the Furnace

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POPULAR CONCRETE IS AUTOMATICALLY PROPORTIONED BY WEIGHT One of the latest developments in build- ing equipment is a device that measures and proportions concrete aggregates with extreme accuracy, and with a saving in time and labor. This new proportioner measures the aggregates by weight in- tead of volume, and only one man is required to operate the mixer as well as the proportioner. Constructed so that it ‘an be framed MECHANICS 38 PIGEONS AS SUBSTITUTES FOR WIRELESS MESSAGES Innumerable have been the uses of homing pigeons, in both warlike and peaceful services, but it has remained for an ingenious resident of San Pedro, Calif., to make use of them as a substitute for wireless messages in connection with the fishing industry. The home loft for the pigeons is situated on shore at a point central with relation to the area, extending 70 into any stand- rd bin isa teel panel hav- ng at its lower nd three open- ngs fitted with bin gates, the center lg for nd the the sides for and and ce- ment, respece- tively. The rates are oper- ited by cams on a shaft above them that extends the full width of the panel. Bell cranks, keyed to each end of the shaft, each a long vertical irm which is connected by a eries of cables and pulleys to one be- stone, two at ave supports for three counter- weights, one for each of the ag- gregates, pro- portioned suitably so. that, weight of equal to its counter- weight is discharged into an auxiliary hopper hung from the lower arm of the bell cranks, this counterweight rises, and through the movement of the horizontal shaft, automatically closes the gate on the stone bin, and opens the cement bin. The additional weight of the cement in the auxiliary hopper has a similar effect on the gate of the sand bin. The batch is then complete, and is dumped from the auxiliary hopper into the concrete mixer, returning every part to its original posi- tion, ready to proportion another batch. when a stone Concrete Proportioner That, by Means of Three Counterweights, Discharges from Three Bin Gates below Them, Measured Quan- tities of Stone, Sand, and Cement into a Hopper, from Which They Pass to the Mixer; after the Discharge, All the Parts are Automatically Returned to Original Position miles radially, over which the fishing operate. Each boat takes out a pigeon, and at the end of the day, before starting for the cannery,there is attached to the bird’s leg a rez- ulation army container, in which a slip of paper reports the day’s catch It takes each boat six hours to return tothe cannery, and each pigeon not more than one to reach the homing loft, which is so con structed that as the intelligent little winged messenger boats pushes its way through the en- trance door, an electrical con nection rings a bell that announces its arrival. The note is then taken off, and the information is telephoned to the cannery. The value of this advance information is obvious. @The practice of crowding around an airplane when it is about to take off is a very dangerous one and resulted fatally at Red Bank, N. J., recently. An airman landed on the frozen river, and such a crowd collected that there was danger of the ice giving way. In attempting to leave the river, the airplane struck the crowd, killing one woman and injuring several people.

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88 POPULAR MECHANICS CEMENT TENNIS COURTS LAID WITH PERMANENT LINES Tennis has been growing rapidly in popularity as a sport, throughout the country, and to increase the playing sea- son, asphalt and cement are being adopted for surfacing tennis courts. Though the Pacific coast led in the use of this type of court, New York City, which has lately taken up the idea, has introduced a spring and later in the fall than clay or grass courts. After a rain, it is not nec- essary to wait for them to dry, and they do not require rolling and sprinkling to keep them in condition. BAGGING LAUNDRY ELIMINATES UNSIGHTLY MARKING Marking “flat-work” laundry with in delible hieroglyphics as a means of iden tifying it is no longer necessary under a _ sys- tem installed by a Massa chusetts laundry. Under this system the house- wife may send her best tablecloths, centerpieces, doilies, etc., to the laun- dry without fear of hav ing them returned with their appearance marred by marks. The goods are sent to the laundry in the usual way—with the name on the package. At the plant the soiled articles are put into an individ- Laying a Cement-Surface Tennis Court: High, but There Is Practically No Expense for new method of lining the courts. The lines were formerly painted on the sur- face of the cement. Now, while the ce- ment is still soft, the lines are grooved out and the material removed. After the court, which is laid with cement colored with lampblack to relieve the glare, has hardened, the grooves are filled with white cement. The expansion joint, nec- essary for such a large surface of cement, The Cement is Colored with Lampblack to Relieve the Glare, and the Lines are Made by Laying White Cement n Grooves in the Surface is placed under the net, where it does not interfere with the playing. These courts can be used several weeks earlier in the The Initial Cost of Such Courts Is Upkeep, Permit a Much Longer Playing Season Than Grass or Clay Courts ual cloth container, in which they remain while going through the various processes of cleansing Marks on the container instead of on the articles permit quick identification after the laundering. Of course, if there is enough in one batch of laundry to fill more than one container, two or three are used. The first week the no-mark system was in use, there was a reduction of 70 per cent in the number of articles reported missing. Through this process the com pany expects to lower the number of lost articles to an extremely small figure. The chances of soiled articles, especially if they are worn thin, being torn or dam aged in the washing processes, are also greatly reduced, as the containers afford the articles additional protection. and They RAILROAD IN ALASKA OPENED FROM SEWARD TO FAIRBANKS Formal opening, accompanied with elaborate ceremonies, of the government railroad in Alaska, between Seward and Fairbanks, took place early in February. Representatives of the chambers of com- merce of several Pacific-coast cities were present, and the event was celebrated by an excursion over the entire system.

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POPULAR Above: A Truck on Which is Mounted One of the New Centrifugal Machine Guns. The Motor on the Rear Supplies the Power for Operating the Gun MECHANICS Above: The Drum Which Throws the Round Steel Bullets, and Which Incloses the Principal Mechanism of the Gun. Left: The Method of Mounting the New Gun, on the Dashboard of an Automobile, is Shown in This Picture, Taken during the Recent Tests at Sea Girt, New Jersey PHOTOS COPYRIGHT, KEYSTONE VIEW CO. TESTS MADE OF MACHINE GUN USING CENTRIFUGAL FORCE Tests were made, not long ago, by the New York National Guard, at Sea Girt, N. J., of a new machine gun of the type in which centrifugal force instead of an ex- plosive is employed to propel the bullets, which are of the ball-shot type and made of steel. They are thrown from a drumlike gun, mounted on the front of a motor truck, at the rate of 1,200 a min- ute. The power is furnished by a special gasoline motor mounted on the rear of the truck. It is possible to regulate the velocity of the bullets. At their greatest velocity they are capable of killing a man at 2,000 yd. This can be reduced so that, at extremely short ranges, they will merely wound without penetrating the hody or causing a fatal injury. Because of this feature, it is hoped that this gun will prove useful in controlling riots without causing fatalities. It was with the idea of this use in mind that the tests were carried out, and the results proved most gratifying. i NEW CROSSING SIGNAL HELPS GUARD DEATH TRAPS In a determined effort to cut down the tremendous loss of life, and the many in- juries which due to accidents, a large number of illuminated crossing signs of a new type are being in- stalled. Be- tween two bright-red lights is dis- played the warning, “Stop.” These signs are at- tached to the posts of the ordinary high- way-crossing sign. The two oil lamps have large founts and long-tim: burners. Back of the letters is a translu- are grade-crossing

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390 cent glass, on which light is thrown from the two lamps by mirrors set at an angle. By this means the light can be seen clearly for nearly 300 ft. Each container will hold a gallon of oil. The lamps will burn continuously for about a month with a long-time burning oil. NEW GIANT OFFICE STRUCTURE AROUND OLD DWARF BUILDING The greater will include the less—very much greater, and very much less—and include it very completely in a new Chi- att 3 MELEE LY tthe oe pAHRIALE LE sal gamit inane Tru F poe ee pe pee 5 i et t r Model, on a Scale ot One-Eighth Inch to the Foot, of a 21-Story Chicago Office Building to be Erected around the Old Two-Story Brick Building Which the Owner Refused to Vacate cago office building about to be erected, at a total cost of $4,000,000, on the site of old Fort Dearborn, facing the new Michi- gan Avenue bridge. The area of the site POPULAR MECHANICS is 13,600 sq. ft., and of this only 1,200 sq. ft., less than one-tenth, is occupied by an old two-story brick building, the owner of which refused to sell out. Conse quently, the new building will be built around it, leaving an air shaft above it. The new building will be a superlative contrast to the old one, in both size and finish, for it is to be 260 ft. high, sur- mounted by a 60-ft. tower, and will hav: an all-stone finish outside, with marb floors and corridors inside. It will have lights all around, and in every respect will be the last word in modern buildings. ofh cK — SELLING GAS BY HEAT VALUE AS WELL AS BY VOLUME The difference of opinion, prevalent in every country, between the producer and the consumer regarding the quality of the gas furnished for heating and power pur- poses, was recently settled in the United Kingdom by measuring not only the vol- ume of the gas consumed, but also the number of thermal units contained in the gas, which is paid for accordingly. Before reaching the ordinary volume meter, the gas passes through a heat- recording calorimeter at some point in the distributing mains of the gas com- pany, and this instrument graphically re- cords on paper tape the calorific value of the gas at all hours of the day. These records are periodically exposed in some public place for the inspection of the consumers. SNAP-ON RUBBER HEELS ATTACHED BY WEARER Applying the principle of the snap fastener, commonly used on gloves, to the attaching of rub- ber heels, is the idea of an eastern inventor. After first fitting the shoe with a metal plate containing 12 metal studs hav- ing enlarged heads, the rubber heels, which have corresponding cavities on the inner side, are pressed over the studs until they snap into place. Those who wear their heels down on one side can interchange them frequently, thus assuring a longer life and a neater appearance of the heel.

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POPULAR MECHANICS = Left: Door on One Side of Wheelhouse Open, ye the Rollers, by Means Which the Illicit Cargo Fin | Thrown into the Sea The Iron Crate That was Kept inside the Wheelhouse, and was Jettisoned When the Boat was Pursued by Revenue Cutters i Used for Smuggling Contraband from Canada to the United States, That was Finally Captured in the Lake Washington Ship Canal at Seattle: The Goods were Left inside the Wheelhouse in a Large Iron Crate Which could be Pushed through the Door and Thrown Overboard SMUGGLERS USE CLEVER DUMPING DEVICE By LAWRENCE WILLIAM PEDROSE is said to be one of the clev- When the cargo had to be jettisoned in devices ever de veloped for deep water, the position of the crate wa gling was uncovered on Puget Sound marked by a small floating buoy, attached i by Federal officers when a speedy to the sunken contraband wit] ’ h a line r boat, believed for several Stn l Roat Boat The boat was also equipped with a com to be a successful smuggler of illicit plete deep-sea diver’s outfit and a set oi goods from Canada into the United grappling hooks. States, was captured in the Lake Wash- It had been known for some time, Fed- gton Ship Canal at Seattle. eral officers state, that a dumping device \ feature of the boat’s equipment was was in use on some of the smuggling mechanical device by which the illicit boats, but a complete outfit of this type before been captured \long ‘argo could be temporarily jettisoned had never hould it be overtaken by revenue cutters with the seizure, more than $2,000 worth Inside the wheelhouse was a specially of contraband was taken, which made it built runway with smoothly working possible for the government to confiscate rollers, on which rested a large crate the boat. formed of iron grating, capable of hold ing several thousand dollars’ worth of UNIFORM FIRE CALL ADOPTED contraband: This runway connected BY CANADIAN COMMUNITIES vith rollers on either side of the deck opposite the wheelhouse. The crate wit! \ll the cities, towns, and municipalities its illicit cargo rested inside the wheel- of Canada have agreed to adopt the num- house with the doors closed. Should the “100” for telephone fire calls. Hence- hoat be pursued and in danger of capture either .door of the wheelhouse could be opened and the crate noiselessly run over the side of the vessel. forth when the ope rator gets this number, no matter whether there are exchanges in the city or not, she will know immed ately that a fire call is wanted.

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POPULAR MECHANICS TILTING TESTS PROVE SAFETY OF BIG MOTOR BUSSES Tilting tests of moto: busses, used in Ney York City, showed that their center of gravity i extremely low, only 52 in. from the ground Their safety is furthe: proved by the fact that in the 14 years they hav been used, they hav: safely carried 270,000,00) passengers and have had only two overturns Both were due to an ex traordinary combinatio: of circumstances. Thi same type of bus is use in Chicago, Detroit, To ronto, Can., and othe: woewono nos § Jarge cities, and in a The Tilting Test Which Showed the Center of Gravity of These Big , Busses to Be Only 52 Inches from the Ground, an Assurance of Safety these plac aad Ww ith al Which is Supported by the Record of 14 Years’ Use in New York City equal degree ot satety. ANIMATED STATISTICS TELL the significant message: “We Represe: ACCIDENT STORY the Syracuse People Who Lost Th Lives Last Year by Accident.” Thousand Walking letters that told their story in of spectators watched the parade, a: a most efiective manner were the striking naturally they were deeply impressed b the message so _ vivid! presented. Of the 63 who were killed by acci dent in 1920, 17 were bo and girls who lost th« lives in accidents tha could have been pr vented. The marchers were pr: ceded in the parade bs large truck, carrying immense sign which read, “First Think of You Safety,” and an amb lance containing a sadl wrecked man anda nut At the head of the col umn of children a bo carried a placard — “63 Count Us.” Following th: sentence represented | the children was a trucl load of children wavin flags and bobbing bal! A Striking Feature of a Safety-First Parade in Syracuse, New York, Which loons up and down, cat Speaks for Itself by a Graphical Representation of the Results rying out the spirit of the of Accidents Which might have been Avoided : sign that they displayed. feature of a safety-first parade at Syra- and which bore the words: “We Ar cuse, N. Y. There were 63 children in Happy Because We Practice the A. B. ‘ the group, each child bearing one letter of of Safety—Always Be Careful.”

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POPULAR MECHANICS lless-Tread Tractor, Showing the Method of Attaching a V-Shaped Plow for Scraping Snow from Roads: The Chain and Pulley Permit the Raising and Lowering of the Plow as may be Desired, the Lift being Operated from the Driver’s Seat by a Hand Wheel ENDLESS-TREAD TRACTOR MADE TO SERVE AS SNOWPLOW \nother | adaptation of the endless- ead tractor, which gained wartime fame n the tank service, is seen in a snowplow being turned out by an eastern manufac rer of road machinery. This tractor is quipped with a large V-shaped plow. It suspended, at the front, in such a way that it be raised clear or lowered to crape away snow which has drifted onto can roadw ay. WIRELESS MESSAGES IMMUNE FROM BEING “PICKED UP” Privacy of wireless communications has en made possible, it is said, by a method hich is the discovery of an electrical en- gineer in the employ of the Ukrainian (;overnment. Utilizing his idea, messages ma vit by other the same traighten power y be sent to a definite receiving station, hout danger of their being “picked up” operators, man out, lines” of It is reported that found a way to and group, the “locked the magnetic field into parallel rays, which can penetrate moun- tains, thus avoiding the necessity of high intenne. has also @ When you want anything and do not know where to get it, write Bureau of Information, Popular Mechanics, Chi- cago. CLEVER IDEA MAKES CONCRETE DAM A FOAMING WATERFALL In t neat | been Forest Preserve, an ingenious idea h give a small c he Cook County alatine, IIl., used to the appearance of a yncrete dat foaming waterfa The dam retains a small pond during no: mal weather. When it rains, the pond The Face of the Dam, Showing How the Rocks are Imbedded in the Concrete to Procure the Effect of a Foaming Waterfall

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394 POPULAK overflows and the water must be carried off into a ravine. A shallow channel, passing under the roadway which runs along the top of the dam, carries the water over it. For a tew feet the face of the dam is perpendicular and then merges into a more gentle slope. Small rocks have been imbedded in the concrete- of this slope. When the sheet of water strikes them, it breaks into a splashing mass. MODEL OF ONE MOLECULE ENORMOUSLY MAGNIFIED The structure of a molecule which, be- fore the discovery of radium, was consid- ered by physicists to be the minutest par- COPYRIGHT, UNDERWOOD & UNDERWOOD Model of a Molecule 250,000,000 Times Its Size, Being Nine Inches in Diameter: The Component Atoms are Shown by Putty Balls of Various Colors ticle of matter capable of separate exist- ence, has been reproduced in a model shown recently at the lllth meeting of the American Physics Society. The model is in three dimensions, superficially of crystalline form, and with a diameter of 9 in. This makes it 250,000,000 times as large as an actual molecule, and therefore there is plenty of room to display its com- ponent atoms, which are represented by putty balls of various bright colors. These are all constructed in proper pro- portion and location, and show that the arrangement is similar to the solar sys- tem, and all other planetary systems of the universe, leading to the deduction that these atoms, like the planets, are revolv- ing in orbits within the molecule. MECHANICS CHICAGO’S POWER STATIONS HAVE ENORMOUS CAPACITY “Cutting in” two 45,000-hp. units of th: Calumet station, now under construc tion, brought the total generating capac ity of the Chicago Commonwealth Edi son Company up to the huge amount oi 880,000 hp. When the Calumet station is completed, at a cost of $20,000,000, its output will be 250,000 hp., thus taking rank as one of the largest electric-gener ating plants in the world. For the first time in a decade, and made possible by this latest addition, the company will have a supply of power available that ex ceeds the demand, and it is estimated that this condition will continue for two years. With its vast production of power, Chicago has become the hub of a gigantic network of interconnected electric-trans- mission lines in the. upper Mississippi Valley, reaching from Minnesota to Ken- tucky. RECIPROCATING MOTOR USED IN ELECTRIC HAIR CLIPPER Hair clipping by electricity is no ne idea, but the introduction of an appliance for this purpose that possesses a recipro- cating motor, is a distinct departure from ordinary usage. Unlike other electric hair-cutting machines, the driving motor for the blades of this clipper is installed in the handle. The usual connection. is made to a lighting outlet of 110-volt alter nating current, and at .26-ampere flow the apparatus consumes from 18 to 25 watts. Because of the extreme flexibility obtained in the use of the instrument, its appearance will no doubt be welcomed by barbers in general, and should prove a great aid to the tonsorial trade. ~ ee Top: Electric Hair Clipper with Outer Casing Re- moved, Showing Interior Mechanism. Bottom: Clipper as It Appears in Barber’s Hands

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€ BORROWING A LAKE BOTTOM 70 RAISE GRAIN By Fred S Walker Dredger, Seen in the Distance, at Work Building a Levee, or Dike, across a Section of Tulare Lake, as the First Step in Reclamation of Lake Bottom for Farming Purposes: When the Levee is Completed the Water will be Pumped across It, Leaving One Portion of the Lake Bottom Dry \ISING a grain crop, as a rule, re- more than 100 miles in length, from the quires a farmer rather than an engi- highest mountains in the United States neer, yet during the past 30 years farming has its natural flow into this lake; that in the bottom the laws of Cal Tulare Lake (GL Ps ifornia recog in California " ¢ | nize the lake has presented Sea _ PA bottom as the an engineering WS ? , . only outlet for problem that 7A yA a dozen streams has never been é A on this water satisfactorily = * bas Oe ert shed, and that . ~. og 4 ‘ solved, even * y } es the time of pos though, in 1920, “Sk — + awh sible operations a yield of wheat | . See : is limited, som: and barley ag- | { : ; conception of gregating in » i\) We the difficultie value more NO “V SRS Goose cant h Vee, of the develop than $5,000,000 , : >> ment involved was harvested Sax Falun \ ’ Pe ay mav be seen. and hauled to | ' Pie ye" In 1892, the market from ‘ aa : lake was de the last low = Me ee, hin scribed as “th reaches of what ASY fA ety largest body of has been an “6 ; ' >. ne fresh wate inland fresh- | ba i 2G west of the Mis water sea. Ay - See ‘7 te... sissippi River.” Through it all kh i = G Geologists the lake has i n a claim that age only slowly fe ; S$ >>» ago the drain yielded to the | . { 2 age of this ex attemptsto | — treme uppe! convert its an- ———_ section of th cient bed to the SANTA BAP BARA , San Joaqui: uses of agricul- Valley wa ture. When it e ai obstructed by is realized that Map of the Watershed of Upper San Joaquin Valley and the 4], ¢ débri = a : Tulare Lake Basin, as It Was in 1890, Before the 1 a watershed Reclamation Operations were Started wasne

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POPULAR MECHANICS Hauling Five Four-Horse Scrapers by Means of One 45-Horsepower Tractor to Build a Levee to Protect Growing Grain from Threatened Floods: This Battery of Scrapers Makes It Possible to Build a Levee Three Feet High and One Mile Long in 12 Hours the channel by Kings River, filling it toa River, the principal of which are Kings depth of 40 ft., and thus forming a basin and Kern rivers, having their headwaters on the plain, catching the waters of all on the western slopes of Mt. Whitney— the streams south of the San Joaquin Kings River flowing north and Kern Se River south from that point and describing a great oval before again uniting in the waters of Tulare Lake. In 1852, when Tulare Lake was first surveyed, it spread over 1,000 square miles of territory and broke over its northern rimintothe San Joaquin River, but not in a suffi- Seo —— ¥ Above: Digging Machine Working on Levee to Protect the Enormous Wheat Field, Seen at Left, from Danger of Floods. Below: Looking from Lake toward a Section of the Levee That Bounds It. Two Rows of Willows on Lake Side are Planted to Protect the Soil from Waves

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POPULAR MECHANICS ee ase d st Part of a Battery of Tractors Hauling Rotary-Disk Plows over the Reclaimed Bed of Tulare Lake in the Fall, fter the Season's Crop had been Harvested: Deep Plowing Is Not Necessary, and the Disks Turn Over the Top Crust, Providing a Satisfactory Seed Bed ciently powerful stream to form a perma- nent channel. The lake abounded in fish of many kinds—mud cats, perch, and pike being the principal varieties—while reced- ing waters left the shores white with the shells of fresh-water clams. In seasons of flood and heavy rainfall, when the lake was filled with water, it also became filled with rank wild grasses and tules, where the fish and clams multiplied. Then in seasons of drought the evaporation of the water was so great on the nearly flat surface as to leave millions of fish stranded on the mudflats of the plain. The shores of the lake became putrid with decaying fish and vegetable matter. This process, repeated over and over through many decades, left the bottom lands incal- culably rich in animal and vegetable de- posits, and finally paved the way for gambling against the chance of flood sea- sons, and also to the more gradual work of permanent reclamation. In the early efforts of reclamation a few furrows around large tracts by individual growers were often sufficient to hold the water from flooding the land; but as the Above: One Tractor Pulling 125 Feet of Rollers over the Growing Grain to Pack the Soil about the Roots and Prevent Evaporation. Below: Hauling the Grain to Market with Teams of 10 Horses or Mules, Handled by a Single Driver, Who Usually Rides the Near Wheel Horse

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398 POPULAR area of the lake was decreased by this method, higher and stronger levees be- came necessary. A break in the levees of one grower often caused heavy loss to scores of others. Concerted effort became urgent, and led to the formation of recla- Dense Growth of Grain on Part of a 5,000-Acre Field, Taken Them Down Till The Yield Was 70 Bushels an Acre Just Before the Heads Filled and They Touched the Ground. Weighted mation districts and systematization of the construction of greater bulwarks against flood. Unquestionably he!ping to reclaim the lake to agriculture are irrigation projects on the higher plain around the lake; where intensive farming is profitable. Alfalfa fields early took the place of the old stock ranges, while horticulture and viticulture have proved less insecure than dry farming of grain on the arid plain. These indus- have required vast quantities of mountain water in addition to the local rains. Then, a score of years the foothill section of the Sierras developed one of the most famous citrus belts in.the annals of industrial enterprise, and in a ilecade the towns of Lindsay and Porters- ville have become commercial centers for the orange, the grapefruit, and the lemon. \With the rise of the citrus culture, the water from the normal rainfall and the slowly melting snow of the high mountain region went into use for irrigation long before it reached the lake in dry and nor- mal years. Each irrigation district, how- ever, takes care of its own affairs, will take only such water as it needs from day to day, and turns back into the rivers any surplus of the snow waters of the high inountains which fill every stream during a few sudden warm days in May and June. These freshets, which come three months after grain must be seeded in the lake bot- tom, form the basis of the hazard under which the lake farmer must work. This, then, is the situation today. The Tulare Lake now covers only 42 square tries ago, MECHANICS miles of territory, around which an im- mense levee, more than 20 ft. high and 100 ft. broad, cuts this final remnant of lake bottom from the other 958 square miles of fertile valley land which it once held. In dry seasons, outside the levee, are farm lands under irrigation stretching for 50 miles across the plain to the foothills; inside the levee are 42 sections of bottomless mud, level as a floor, yet covered in a great part by a few inches of tepid water. It is miles away from rodent pests, is free from stones, roots, and weeds of any kind, and seemingly invites the farmer to drain and plant in its matchless fertility. Yet every grower who engages in the enter prise does so with the knowledge that this muddy pond is the le- gally allotted catch basin for more than 7,000 square miles of moun- tain watershed, and now 20 times smaller than it once was. Tractor power has proved to be the key to success in farming the bottom of Tulare Lake. Without the facility to perform large operations under limited-time pres sure, every attempt of the growers would have been doomed to failure. With two feet of water in the lake bot- tom at the deepest point, spreading over an area of more than 14,000 acres, the first step toward the production of a grain crop is a battery of dredgers, which run levees, or dikes, through the lake from end to end. Then, with large motor driven centrifugal pumps, the water is drawn out of one section into another, to Timbering the Levee to Prevent It from _ being Washed Away by the Waves: The Water Here Stood 17 Feet Deep against the Levee facilitate the drying of each tract to be farmed. Finally, it is pumped across the large levee, protecting the reclamation

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POPULAR MECHANICS dU Battery of Six Corn Planters Operating on the Reclaimed Bed of Tulare Lake: They are All Hauled by One ractor, Making It Possible to Plant 12 Rows Simultaneously with the Labor of Only Two Men, One on the Tractor, districts outside, and is used for the irri- vation of the higher ground. Removal of the water leaves a sea of hottomless mud, picturesquely described is “not bearing the weight of a mosquito.” \ sheep or an ox venturing into it is help- less and soon sinks from sight. Warm dry winds and spring sunshine, however, lry the surface within a short time so it vill bear the weight of tractors of the track-layer type, though it shakes under a man’s foot, and for months will not bear the pulling weight of horses. During the entire course of the work of plowing, seeding, and caring for the crop, no do- mestic animal is permitted to enter the district. Naturally, for 20 miles across this expanse, no permanent house, no tree or fence may be seen. For temporary use by tractor operators and helpers, mosquito-screened camps are set up for instant removal in case of heavy rains or mountain floods. As soon as the drying soil permits, trac- tors, pulling rotary plows and working in batteries, turn under the top crust and provide a seed bed for the coming crop. rhis is followed by seeding and harrowing on a gigantic scale. After the grain is a few inches in height the soil must be treated to prevent too great evaporation. \s the drying process goes on after the planting is complete, the soil cracks and crumbles into a myriad of tiny fissures. This is overcome, in part, by pulverizing the soil with rollers which packs the soil and keeps the moisture about the roots of the plants. Working day and night, a tractor, pulling 125 ft. of rollers, rolls and packs 280 acres of land in 24 hours. the Other on the Planters The grain sown, sprouted, and rolled, there is left for the operator only the work of strengthening and repairing the levees. The weather of the high Sierras has much to do with successful crop conditions in the lake bottom. A mild spring brings ibout a gradual melting of the banked-up snow in the mountains, but with a back- ward spring, followed by warm rains and sunshine during May and early June, every stream out of the snows becomes a tum- bling cataract of potential flood waters. Then every grower in the wheat pit of the lake bottom is transformed from a placid farmer into a dynamic force for concentra- tion and cooperation. Barometer changes are reported hourly from forester stations and electric power plants in the moun- tains, and the rise of a fraction of an inch in every stream is reported 24 to 36 hours before it can reach the valley. Specialists employed by the lake farmers know the capacity of every irrigating stream out ol the rivers, and the probable demand for every foot of water. What they do not know, and what they must gamble on, is the probable duration of a flood. This happened on one last year and it was only met by prompt and decisive action on the part of the growers. One grower in the irrigation district out- side the big lake levee held 5,000 acres of grain that would average in the neighbor- hood of 25 bushels to the acre, as it stood on the ground late in May. Acting for the lake-bottom growers, a committee waited upon this grower and quickly closed a deal for his entire holdings in growing grain at a price of $70,000. Then, as the flood waters swept down the sand) occasit yn

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400 POPULAR bottom of the Kings River, a dam was thrown across the stream and the cutting of the river levee sent the flood into this new 5,000-acre reservoir. Again the op- erators gambled on the chance that this area would suffice to hold the waters until the hot spell ceased. Hundreds of men armed with shovels and empty sacks pa- trolled the levees ceaselessly, while steam dredges operated day and night, raising and strengthening the embankments. Still the hot wave in the hills filled the streams, and hour by hour the battle went on to keep the levee from breaking and flooding the country, which would have involved heavy damage suits for loss of crops. But the flood subsided and the levee held, and for the first time in history a full harvest was taken from the lake bottom. Yet, though the flood condition had been met, the great problem of lake-bot- tom farming was but half solved. One inch of rain might again render it a slimy mass of mud, so slippery and sticky that nothing could be hauled away until it dried. An inch of early-fall rain, too, would wet the sacks of grain in the wake of the harvesters, and these, drying in the blistering sun, would rot paper. If harvesting was done, it would be neces- sary to remove the grain before’the fall rains, which sometimes fall in September. The harvest began during the third week of June. The lake bed was a sea of standing grain, relieved only by tall stakes, like MECHANICS set on section corners to mark individual holdings, and to guide the work of the harvester. Grain “buck” wagons followed close upon the harvester, and every effort was made to haul the grain from the field and place it near the roadways as rapidly as the filled sacks fell from the machin With every facility for transportation in use, moving 700 tons of grain daily, it would require 100 days to get the crop out of the lake, even after it was harvested To speed the work, one firm, having 5,000 acres of wheat, employed eight large trac tors in the harvest field cutting and har- vesting the grain, while smaller tractors, pulling trains of five low-wheeled farn wagons, followed the harvesters, gather ing the filled sacks and hauling them to roadways previously rolled and _ packed where heavy motor trucks and freight teams hauled them to warehouses depots. It is claimed that every straw in thi immense crop was utilized, for followin: close upon the removal of the grain from the field, sheep were turned into the stub ble in droves of 2,000 to 5,000 each. Smal! camps, embracing a sleeping tent for the herder and troughs for watering the ani mals, were established and moved from place to place as the need arose. Special equipped supply wagons visited thes camps daily. November 1 the lak: bed was again seemingly as bare as befor the farming operations began. and sy ELECTRIC VULCANIZER HAS MANY MERITS Electric Vulcanizer, Showing Molds, Tube Rack, and Hot Table on Top, with Switches and Pilot Lamps at End ficient electrical vulcanizing, excluding all steam apparatu and the consequent danger of e» plosion, is performed with an ap pliance develoned by a Minne apolis firm. Three molds ar provided for holding the tires, in sizes of 3 to 31% in., 4 to 4% in and 5 to 51% in., together wit! extra bead molds for accommo dating both the clincher and o1 dinary-type casings. Each mold can operated independently has individual pilot lamps, and the whole receives power from 4 cord attachment any light socket. In addition are supplied a hot table for vulcanizing inne tubes, and a bracket upon. which these can be hung while the wor! is being done. As many of the be to we units as desired may be joined so that tire repairs in any siz shop can be effectually executed.

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POPULAR MECHANICS Novel Farm Tractor Making an Abrupt Turn: The Large Traction Wheel has been Turned at Right Angles to the Direction in Which the Tractor was Traveling, and will Thus Follow a Curve around a Stationary Center FRENCH TRACTOR SIMPLE AND ORIGINAL IN DESIGN To all intents and purposes the ordinary gas distribution upon one rotary device, farm tractor is a more or less skillful and bears no resemblance whatever to adaptation of the principles of opera- any automobile motor. This new tractor tion embodied in the automobile. More- consists of one large traction wheel some- over, these trac- what in the tors, as a rule, , —~ nature of a are adapted for . wide disk hauling the Se wheel, which same kind of | 2 : contains in its farm imple- interior a com- ments as are . plete system of used with , : ; trans mis- horses. A novel - sion and speed type of tractor ™ gears. The mo- has been con- - 4 is = tor and its ad- structed in F. ; ni juncts, as well France that has Wh as the wheel little more in , :| = and its sup- common with esate ad sia ” ports and the the ordinary . ‘i ‘ water - cool- motor car than wa . ing radiator the fact that it ae Oe ’ soll form a unit is driven by an omen that is pivoted internal-com- — in a horizontal bustion engine. — circular frame, Even at that, é ee ee a to which can its motor, Pe a a ; be attached any which consists suitable means of two opposed for hauling the cylieGets),. AQ eee implements, as valveless, de- Front View of Tractor, Showing Large Traction Wheel in Cen- ‘ e ter: To the Right of It Are the Motor and Radiator. To the well as a trailer pending for itS Left Are Steering Devices That Turn These Parts as a Unit which supports,

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402 on two small wheels, the seat for the driver. With this construction, it is easy to make very abrupt changes of direc- tion. Beside the driver's seat is a lever by which the speed is controlled and the tractor driven forward or reversed. The models that have been built up to the present have proved to be very efficient in doing the work for which they were designed. IMPROVED HOLDER SQUEEZES TOOTHPASTE FROM TUBE A recently invented fixture, for holding and squeezing a tube of toothpaste, is said to have a definite advan- tage over other devices of this kind. When the pressure on the tube is re- leased, no more paste escapes [fom tt..- 1% consists of a boxlike case containing a movable. plate, whith. 4.5 pressed back by bearing down on a han- dle protruding from the front of the box. The tube is held upside down in the box by means of a slot in the top, through which the bottom of the tube is inserted and bent over. The plate squeezes the tube with a flattening effect. STRAINER OF STEEL WOOL KEEPS PIPE STEM OPEN Clogged stems, that bane of pipe users, can be averted by the use of a new smok- ers’ accessory, which con- sists of a small, loosely wound ball of fine steel wool. This, pressed down against the bottom of the pipe bowl, al- lows free pas- sage of the smoke, but prevents tiny particles of tobacco from entering the stem. POPULAR MECHANICS DENATURED ALCOHOL ALWAYS A DANGEROUS POISON Reports of denatured-alcohol poison ing, since the adoption of prohibition, in dicate a failure fully to understand what denatured alcohol really is. Denatured alcohol is alcohol to which some poison ous substance has been added to make it unfit for internal use, and is always sold with a poison label on the container Some of the mixtures are: carbolic acid 1 part, alcohol 99 parts; formaldehyde 1 part, alcohol 99 parts; corrosive sublimat« 1 part, alcohol 2,000 parts; corrosive sub- limate 115 gr., hydrochloric acid 2 dr., al cohol 4 0z.; formaldehyde 2 parts, glycer ine 2 parts, alcohol 96 parts; acid 1 dr., tannic acid 1 dr., water 1 pt.; alum 1% oz., formaldehyde 2 dr., camphor 1 oz., alcohol 1 pt., water 1 pt.; lysol 1 part, alcohol 99 parts. All these are violent poisons, astringents, or cor rosives, strong enough to cause intense suffering and lingering physical decay The proportions of denaturing substances are in some cases so small that they can not readily be detected by smell, and in others entirely imperceptible. carbolic alcohol 1 pt OLD SWEDISH COIN TEN INCHES SQUARE IS LARGEST KNOWN Probably the largest coin in the world is one belonging to Farren Zerbe, inte nationally famous expert on rare coins. See ee ae It is a piece of stamped copper plate 10 in. square, and weighs 614 lb. It ha a value of “4 Daler” (the daler was a coin of vary ing value) stamped on it, and the date 1730. Such coins were commonly used in Sweden for some time during and after the wars of Charles XII. It is part of a collection of more than 30,000 speci- mens, representing mediums of exchange of all countries and periods from the earliest times to the present day. The total face, or original exchange, value of the collection is counted in millions, but no present value has ever been placed on it Many of the coins are, of course, rare, and of much greater value than their face.

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POPULAR SPECIAL RACING MOTOR- CYCLE DESIGNED BY ENGLISH RIDER \ 20-hp. motorcycle of novel design has been constructed by W. Baker, a well-known Eng- h motorcycle Uy, racer. The ma- ine is especially designed for e cycling pacing track, for the rpose of breaking the present orld’s record of 63 miles in an our, held by Paul Guinard, of Paris, France. It is the highest- powered machine of its kind in Great Britain, and is equipped vith a two-cylinder V-type motor, with a belt drive. The unusual arrangement of the steer- mechanism particularly ng is MECHANICS onspicuous. The speed attained ill depend as much upon the driver’s skill as upon the machine. The New 20-Horsepower Motorcycle Built by an English Motor- cycle Racer for the Purpose of Breaking the World’s Cycle Pacing-Track Record A Perfect Reproduction of a Typical Maine-Coast Herring Weir, the Product of Four Months of Patient Work on the Part of an Old New England Fisherman HAND-DARNING MACHINE WORKS LIKE A LOOM Darning is made into a pleasant occu- pation, it is claimed, when done with a device recently introduced in England. Che litthe darning machine consists of a flat stretcher which is placed behind the hole in the stocking, and over which is slipped a saddle that holds the stocking in place. The thread is wound back and forth over the hole on hooks on this sad- dle. A third piece, hinged on the saddle, hooks under every other thread and raises or depresses them alternately while a threaded needle is passed back and forth between them, as in weaving. Darning Saddle MODEL HERRING WEIR BUILT BY MAINE FISHERMAN Through four long months Capt. John A. worked patiently model herring weir. a perfect reproduction, in miniature, of the type of weir commonly used along the Maine coast. It 3 ft. long and 4 ft wide, one-fiftieth the of the original. The brush was reproduced by the use of straws from a broom and small twigs The beach and rocks were mod- eled in clay and sand. A fisher- man’s cottage is on the rocks. winter \nderton building a The result 1S is size ] WOTK Machine: With the Left-Hand Thumb the is Raised and Depressed, While with the Right Hand the Needle is Passed between the Thread

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40-1 POPULAR NEW ADJUSTABLE HANGER FOR WALL RADIATORS The growing popularity of hanging heating radiators against the wall calls attention to a new adjustable hanging Left: Hanging a Radiator on the New Adjustable Support. Right: Radiator Cut Away to Show How the Support is Adjusted device. It consists of a boxlike bracket, fastened to the wall by a single bolt. A bolt, through a slot in the front of the bracket, is passed between two sections of the radiator and screwed tight with the washer against the inner columns of the two sections. Two brackets are used for each radiator, and the slots make it pos- Below: Under This Shed on Top of Garage Roof are In- stalled, at Extreme Left, a Sheet- Metal Shop; to the Right of That, a Blacksmith Shop, and Farther to the Right, a Paint Shop MECHANICS Left: Air Compressor, with Its Cooling Pipes on Wall Leading to Receiver Tank beneath Them, Which Fur- nishes Supply of Compressed Air to the Spraying Device Seen at Right, being Used for Cleaning the Engine of an Automobile. The Sprayer is Connected by a Hose to a Five-Gallon Can of Distillate sible to bolt them to the wall studs, yet permit the radiator bolts, by moving them laterally, to come between the sections of the radiator. A %%-in. pipe extends down from a slot in the bottom of the bracket It can also be adjusted laterally. Nea: the lower end is a brace which holds the radiator 2!» in. from the wall. At the end is a bracket on which the radiator rests. USE OF THE ROOF FOR SHOPS IS LATEST GARAGE ECONOMY One western garage owner believes in using all the space possible around hi garage, for on the roof of his service station is located sheet-metal, blacksmith and paint shops, and also an apparatus for cleaning engines with a distillate spray. This apparatus consists of an ait compressor and a spraying rig. The dis- tillate is blown from a reeled hose by the compressed air, and the reel for the hose is fitted with a spring which rewinds it when not in use. A large drain is con veniently located to dispose of the resi due from cleaning the engines, and all the dirty or greasy work around the garage is assigned to the lofty workshops. The interior of the garage is thus kept en- tirely free from all smoke, gas, and grease, resulting from this work. Above: Part of the Garage Roof. On the Parapet Wall at the Extreme Right Are the Pipe Coils That Cool the Air While peaaing from the Compressor at Their Left to the Air Tank be- neath Them

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A TWENTY-GAUGE SHOT PISTOL By CAPT. EDWARD C. CROSSMAN INCE the earliest days of their colonial empire, the British have almost con- tinuously found themselves engaged in various arguments with primitive is a practical and most powerful double- barreled hammerless pistol, which will deliver a frightful shock with either its peoples, widely separated in loca- tion, but having the same failing of refusing to consider them- elves dead when duly shot with the British-army firearms pro- vided for the purpose. It proved of no comfort to the relatives of an officer who had gone west” from an assegai stab or the slash of a long knife, to know that the Zulu or Pathan id first been neatly shot by the officer, and had eventually passed on to a heathen paradise. The The 20-Gauge Double-Barreled Shot Pistol, the Missile of Which Is More Deadly Than Even a Dumdum Bul- let, in Position for Firing: With a Smaller Bore, It Resembles in Effect the Sawed-Off Shotgun missiles from the British service rifles and pistols took too long to work, and in the meantime the heathen often proceeded to carve the soldier to suit his taste. \Vherefore appeared both the British dumdum, or mushrooming, bullet for the service .303, and the shotgun pistol which was intended to knock the festive native right buckshot loads, or ordinary loads of ducl shot, such as “6’es” or larger. The pistol is made with single trigger for firing the two barrels, for the officer willing to sink the additional money in the gun. My wife and I tried the British gun, fo Pee a 28 the first time, in fear and trembling. All we could buy for it in the sporting-goods store out from under his hat. f The pistol was evolved | by British gunmakers was a good stiff 20-bore 20- for the use of officers of Close Un, of the 2 load of 4-02, duckshot, reled Shot Pistol in front of 2's dr. of = J powder, which is the heaviest combination the army having to do with natives. It is literally a 20-gauge shot- gun—about .67-caliber if measured in rifle terms—fitted with two short barrels and a pistol handle, especially shaped to per- mit control of the gun and its rather heavy recoil. It has the locks, the frame, the top lever, and even the ejector of the Photo Snapped Instant That Gauge Shot Fired, merless, an Ordinary on a Very Small ordinary shotgun, and the fine workman- ship of the British arm of this class, yet Showing Effect of Recoil: Double-Barreled, put up for the 20-gauge shotgun. Memory of the good stiff jolt of the 6-lb. 20-gauge shotgun when fired at the shoulder, made firing this gun, held in the grip of one lone hand, seem a sure way to depart this sad vale of tears. However, firing it with two hands didn’t develop anything very fearful in the way of kick; the hands and arms, springing under the thrust, seemed to cushion the kick, and it was felt less than with a gun held against a com- paratively unvielding shoulder. Our courage restored, we tried a shot with one hand, pistol- fashion, arm extended, everything at the according to Hoyle. The pistol the 20- a . = h ate " li ] : , | Pistol was rose into the a a littie, ane *, came back into the crotch of the | BR. hand with a good firm jolt, but and Resembles the hand remained intact, and Shotgun . ~aone there was no tendency, as we feared, to tear out of the grip The handle, or grip, is made with an overhang, coming ju above the junction of thumb and hand, 1 and this aided in the control of the up- oO s

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406 POPULAR ward thrust of the gun with its load of Ye oz. of shot, three or four wads, and 2% dr. of smokeless powder, a combina- tion about twice as weighty as the most powerful of ordinary revolvers. We shot up the box of shells without untoward results to our right hands. The gun not a desirable weapon for a woman for target practice, but the lady of the family shot this one single-handed several times to that a is prove woman had no trouble controlling it. At the receiving end of the fire, the gun patterned like any other. cylinder- bored shotgun of this gauge, and with buckshot at 20 yd., was a far more for- midable weapon than any revolver or automatic pistol. A buckshot of a quar- ter-inch larger diameter, with ve- locity of not far from 1,200 ft. per second, more vigorous wallop at short ranges than the bullet from the ordinary type of .32 pocket revolver or automatic pistol, and in a gun of this 20-bore per- suasion one fires from each barrel from eight to fifteen of the round leaden pel- lets, depending on the size. or its has a PILES DRIVEN WITH SWINGING LEAD TO PREVENT BREAKING To do away with the breaking of piles under the weight of the hammer, which caused much trouble in the construction Swinging Lead Used in Place of the Ordinary Type for Driving Piles at an Angle: By This Means the Piles were Prevented from Bending and Breaking MECHANICS The two barrels can be fired, of course, as fast as the hand is recovered from the upward throw of the first shot, and the finger is shifted to the rear trigger. At a dozen feet, or so, the load from one barrel would inflict a knockdown shock, even if only duckshot were used. For stopping a rush or discouraging one that is ready to start, the gun would be much superior to any pistol firing only one ball. And if the shooter fancies hit- ting his quarry with just one round and weighty pellet, the gun will fire 20-gaug round balls, of nearly .67-caliber, and weighing nearly an ounce—but the shooter will know that he’s pulled trigge: on something when he fires it. For a half century the most effective weapon of American firearms for close range fighting has been the sawed-ot shotgun, but it remained for the British gunmakers to put out the shotgun idea in the form of a pistol, easily carried in a holster, and yet as sure death as the old express messenger’s pet, which took up room and advertised its presence by its length. of a sea wall at New York City, the con- tractors devised a swinging lead. A floating derrick was used, and the weight of the piles caused them to penetrate the mud several feet, when placed. By means of guys they were pulled to the right angle and held while being driven. The hammer operated between two 6 by 6-in. timber leads, extending 8 ft. below the butt of the pile, and handled by a hoist- ing tackle and derrick boom. OLD MISSISSIPPI CRAFT USED AS POWER PLANT One of the survivors of the days made famous by Mark Twain’s “Life on the Mississippi,” the steamboat “Andrew Pad dock,” is now serving as a power plant at New Orleans, La. Perched high in the air on stilts, smoke still belches forth in black masses from its tall stacks, but the sternwheel that once churned the murky waters of the river is motionless. The captain and crew of the “Andy,” as it was affectionately termed by the negro roust- abouts, were transferred to other boats, and the crew now consists of two fire- men, each of whom is addressed jocularly as “captain.” The numerous passing craft invariably blow their sirens in salute, and old “Andy” always replies vigorously from its position just beyond the water's The boat is owned by an oil com- edge.

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POPULAR ILECHANICS This Is How the Old Mississippi River Steamboat Now Appears as It Rests High upon Stilts at the Water’s ge and is Used as a Power Plant. The Elevated Sidewalk Leads from the Former Craft to the Bunkerage Offices of the Company, for Which It Furnishes Light, Heat, and Power pany, and furnishes power for its bunker- age offices on the Mississippi River. The yoms in the rear of the offices are occu- pied by employes of the company, and are also heated by the steam from the boat. Very little ceremony attended the lifting of the “Andrew Paddock” from the water, and elevating it to the present position. \fter the stilts were driven in place, it was raised by jacks to its final resting place, thus ending an active river career which extended over a period of 25 years. BUFFALO FUR TO BE SHEARED AND USED LIKE SHEEP’S WOOL There are 8,000 American bisons, com- monly known as buffalo, in captivity, and it is calculated that, if sheared, the fur of animals would furnish 160,000 Ib. of raw material that could be used as a substitute for wool in the manufacture of blankets, sweaters, socks, or other products. That buffalo skin is a greater varmth retainer than any other hide was well known to northern pioneers, and it has now been demonstrated in a prac- tical way, in Canada as well as in this country, that the hair or wool when sheared from the pelt has real commer- cial value. Unfortunately, buffalo can- not be sheared as sheep are, because of their great strength and pugnacity. It will therefore be necessary to handle them in some manner similar to the way unbroken horses are held when being these branded. Held without danger to them- selves or the shearers, the loose wool could be pulled off, and what remains Photo of Buffalo, Taken While in Captivity in Canada, Where Arrangements are being Made for Utilizing the Fur of These Animals as a Substitute for Wool could be sheared. Arrangements are now being made in Canada to shear 5,000 head of buffalo at Wainwright, Alberta. @ For quick transportation, the company owning the diamond mines in the Prov- ince of Kasai, in the Congo State, Africa, sends diamonds to the town of Kinshassa, their nearest destination, by airplan

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108 POPULAR IMITATION CONCRETE BLOCKS ARE MADE OF SANDPAPER Counterfeit concrete blocks for motion- picture photography, when made of sand- paper, have been found to yield a more PEE PE TP i This Imitation Stone Doorway of a Motion-Picture Set is Made by Tacking Sheets of Sandpaper on Wood to Represent Concrete Blocks natural appearance than the genuine product. The stone borders on door- ways have always proved to be a source of annoyance to moving-picture produc- ers, because of the unnatural aspect they present in the finished photograph. By accident, the usefulness of sandpaper in this connection was discovered, and due to the minimum of expense involved, it is thought that the future “stone” of the movies will consist of a sandpaper imi- tation. VALUABLE DIATOMITE MINE IS OPERATED IN OREGON Diatomite, or infusorial earth, com- posed of the remains of myriad micro- scopic underwater organisms, or diatoms, of past ages, is now being mined near Redmond, Ore. A company has acquired nearly 1,000 acres of land, under which is a deposit of this product, 35 ft. in thick- ness and claimed to be 100-per-cent pure. MECHANICS This commodity is used for numerous purposes; for example, as an ingredient i: tooth paste, nail polish, in vulcanized rub ber, in sirup and sugar filters, as an insula tion material, in dynamite, and in cement mixtures for the plastering of marble o1 other hard substances. PECULIAR MACHINE BUILT FOR EMPTYING CANALS On Belle Isle, the municipal playground of Detroit, Mich., there is a_ peculia: pumping machine which was improvise for the purpose of draining the wat: from the canals on the island. Thes: canals are drained and cleared of refus each year in preparation for the skatin; season. The machine is a box, 3 ft. wid and 20 ft. long, open at the ends and mounted on two wagon wheels at the ce: ter. At each end are two sprocket wheels Endless chains pass over these sprocket and through the box. On the chains, at intervals of 14 in., paddles are attached One end of the box is lowered into the canal and the paddles carry the water up through the box to a sluice, which drai: into the river. The machine is operated by either a tractor or a steam engine, ac cording to the amount of power whic! happens to be required. The End of This Peculiar Pump is Lowered intc Canals Which are to be Emptied of Water for Cleaning. The Outside Box is Here Removed

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ARTIFICIAL CRANBERRY BOGS IN THE NORTHWEST Typical Artificial Cranberry Bog in the Pacific Northwest: The Bog has been Drained, Cleared, and then “Scalped” of Vegetation. Take Root in the Peat below It. HORTAGE in the cranberry crop in other parts of the United States last year has focused attention upon this new industry of the Pacific Northwest, which promises to furnish strong competition for the product of the eastern part of the \merican continent. After years of ex- perimentation and selection and the de- velopment of artificial growing areas, the states of Washington and Oregon have come to the front as producers of cran berries in large commercial quantities. Lewis and Clark, in the log of their trip across the con- tinent in the early part of the 19th cen- tury, mention the fine flavor of the wild == cranberries purchased from the Indians along the Columbia River. the wild cranberry bogs was not at- tempted until about 35 years anid continued in a desultory manner until re¢ cently, when a successful means of pre- paring growing ground was developed. Preparation of cranberry ground in the Pacific Northwest is an expensive under- Cultivation of ago, After the Bog has been Drained and Cleared Down to the Peat Bottom, Four Inches of Clean White Sand is t\ Spread on Top of the Peat Through Soil Made of White Sand the Cranberry Shoots are Thrust and This Work Costs $1,000 an Acre taking, the cost being around $1,000 an acre. A wild marsh is drained by ditches, cleared of trees and brush, then the turf is removed by what is called the “scalping” process, leaving bare the peat of the bog. Over the peat is spread a 4-in. layer of clean white sand. Plant- ing is the next proceeding. Vine cuttings are used for this purpose, and are pressed through the sand into the peat with a dibble or planting tool. The vines are planted 10 in. apart, which makes about 60,000 to the acre. During the first year the plants send out runners, which in the second year form a vine growth, 6 = a to 10 in. in height. Every threé \ t he ground must be carefully weeded by hand. Flooding the ground in winter effective in keeping down the For the first year or two after the pro- ductive stage has been reached, the cran- berries must be picked by hand, because the vines are tender. selected, vo or eakts ’ las proved weeds. Thereafter a long- toothed wood comb is used, and is hout 409

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410 ten times faster than hand picking. The field is marked off in 4-ft. avenues with white twine, and a picker is delegated to each avenue. The ground is dry and clean, and the pickers work sitting or POPULAR MECHANICS carefully picked over by hand. Care in picking over the berries is necessary, as one decayed berry will spoil a whole crate. The floor of the warehouse is thoroughly ventilated, and the berries are stored in their crates until time to send them to market, whereupon they are again examined and packed in barrels for shipment. HARMLESS ORGAN- ISM MAKES WATER DISTASTEFUL So small that it is in- visible to the naked eye, a one-celled microscopic organism, called the Sy- nura, has been present in one reservoir connected with the New York water system in sufficient num- bers to taint the whole supply with a nauseating flavor. The Synura is known to be quite harm The Cranberry Warehouse: The Berries Brought In from the Field are Mechanically Separated from the Chaff, Then Carefully Sorted by Hand, after Which They are Stored in the Warehouse until Marketing Time kneeling, gathering the fruit into shal- low dishes, which are emptied from time to time into crates at the end of the av- enues. The crates, which have slatted bottoms to provide ventilation for the berries, are transported to the warehouse as rapidly as they are filled. A machine separates the chaff from the berries, which are then = — — " less, indeed to be pos- sibly even a good tonic, but, unfortunately, when it dies it gives out a mi nute drop of oil so strongly flavored that in comparatively small numbers these or ganisms impart to the whole water sup ply a disagreeable taste. The affected res ervoir, the Kensico basin at Valhalla, has been cut out from the water-supply sys- tem by a by-pass. Thus isolated, the water will be treated with a sulphate-of- copper solution that will kill the Synura. Pickers at Work on an Artificial Cranberry Bog: The Plantation is Marked Off with White Twine into Avenues Four Feet Wide, to Each of Which a Picker is Assigned. They Work Sitting or Kneeling

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POPULAR MECHANICS as LF CIRCULAR SAW MOUNTED ON AUTO CUTS COMMUNITY’S CORDWOOD WHEN this young man, who lives up in northern Wisconsin, needed to cut cordwood for his furnace, he made his inventive mind save him from the back-breaking labor of the handsaw. Removing the body from his automobile, he mounted a circular saw on the chassis, with a belt from the rear wheels to drive it, and nt into the business of cutting wood for the whole community. It proved so profitable that he was soon able to buy a new Car. RADIO CHANGE-OVER SWITCH OF SIMPLE CONSTRUCTION Simplicity of design and operation, in ddition to the elimination of all “kick” in the phone receiver, are the chief fea- tures of a new radio change-over switch. \Vhen changing from sending to receiv- ing, the turning of a knob causes three knife-blade contacts, first, to cut off the power, then ground the aerial for a moment to drain away any accumulated charges, and finally connect the aerial to the receiving circuit. Being small, com- pact, and possessing a high insulation factor, the switch should be welcomed by ll who look for simplicity in radio apparatus. | am \ I Radio Change-Over Switch as It Appears from Left: Right: Sending Side of Switch the Receiving Side. AUTO BABY BED USABLE ALSO IN THE HOUSE A bed, designed to carry babies in mobiles, is equally suitable for use in the auto- te A Baby Bed, Which can be Used Either in an Automo- bile or in the House, should Prove to Be a Great Convenience heavy y st el-gray reinforced and home. It is made of covert cloth, strongly mounted on a folding frame. The frame is of black-enameled steel and is sup- ported by legs. The bed is intended to be placed back of the front seat of the ma- chine. It is 18 in. high, 14% in. wide, and aad ° 33 in. long.

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412 POPULAR JAPANESE WOOD CARVING INCREDIBLY LIFELIKE San Franciscans are paying homage to one of the most remarkable wooden stat- It is the work of ues ever conceived. Life-Size Statue of the Japanese Artist Hananuma Masakichi, Carved in Wood by Himself: Two Thou- sand Pieces were Separately Fashioned and Put Together with Pegs to Complete the Figure Hananuma Masakichi, greatest Japanese artist in wood or ivory, who posed for MECHANICS himself by the aid of adjustable mirrors, and carved his own life-size image from wood. More than 2,000 separate pieces of wood were used, each member of the anatomy having been carved separately before putting the whole together. The joints were perfectly made, dovetailed and glued together, only wooden pegs being used for fastening. With the woodwork completed, the artist applied lacquer to the statue, giving it the appearance oi flesh and blood. Skin blemishes, blue veins, discolorations—everything is repro- duced faithfully. The hair on the figure is the artist's own. He used the clippings from his head and beard, boring tiny holes for th: hairs and setting them in place one by one. The body hairs were all pulled fron his own body and put in exactly the sam: position on the figure as they occupied on himself. The teeth are visible throug! slightly parted lips, and the eyes, mad: of glass by the artist, have the appearance of real eyes. The figure is in every particular, even the most minute, an exact counterpart o! the artist. The carving required three years, even to so adroit and masterly a workman as Masakichi. ROLLER AND ICE SKATING ON RESERVOIR COVER On the large, specially designed con- crete cover of a fire reservoir in Dubuque, Ia., can be seen crowds of youngsters en- joying the unusual roller-skating facili ties offered there. A small store and many other conveniences are installed for the benefit of the youthful merrymaker who daily throng the smooth surface dur- ing the summer months. In cold weather, the cover is flooded with a foot of water, the freezing of which provides an excel- lent ice-skating rink. Showing the Large, Specially Designed Concrete Cover of a Fire Reservoir as It Appears during the Summer Months When Children are Permitted to Use It as a Roller-Skating Rink

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POPULAR MECHANICS The New Road-Grading Tractor, Showing the Novel Design Which is Said to Permit Easy Operation by One Man, and Results in More Economical Work Than can be Done with Horse-Drawn Graders: NEW TRACTOR ROAD GRADER SIMPLE AND ECONOMICAL A company, which has been producing road-building machinery for some time, is now turning out a tractor grader of novel design, for which it claims great ease and economy: of operation. Only one man is required to operate it, both the tractor and grader controls being easily handled from the driver’s seat. The front, or tractor, part turns on a vertical pivot, and is steered by means of a seg- mental gear and pinion operated by the steering wheel, so that the whole machine can be turned in about the same space required by an automobile. The 6-12-hp. motor operates on gasoline, and low- grade fuel can be used effectively. It will grade from 11% to 3 miles of road an hour, about the amount of work done by three teams, at about half the expense of horse grading. COINS COATED WITH POWDER AID IN TRAPPING THIEF In solving a mystery of petty thievery, an English detective coated several coins with a chemical known to produce a stain on the hands, and placed them in the purse of the complainant. Later, upon being informed that some of the money had been stolen, he commanded certain suspects to expose their hands, thereby revealing the telltale stains and obtaining a complete confession and the conviction of the guilty person. The Entire Front Part is Pivoted for Steering BRITISH COLUMBIA ADOPTS AMERICAN TRAFFIC SYSTEM On January 1, this year, the province of British Columbia abandoned the Eng lish custom of driving on the left side of the road and adopted the American “keep to the right” system. With this change, all of Canada, except Nova Scotia, New Brunswick, and one or two other small eastern territories, have come under the American plan. The change was made necessary because of the increasing traffic across the international border and the many accidents resulting from the con- flicting systems. Though the change in- volves heavy expense in altering the entire traffic system of the provinces con- cerned, it is expected to prove profitable. One of the Many Signs in British Columbia Affected by the Changed Traffic Regulations

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114 POPULAR Kitchenette, Showing the Three Compartments at the Left ave Front and Rear Doors, and the Folding Electric Range at the Right PRESIDENT’S TURKEY SHIPPED IN BATTLESHIP CRATE \ Thanksgiving President Harding turkey, ; presented by the Chamber to of Commerce of Cuero, Tex., made the trip Ann Ve COLNE TO gy edi Vnanat, Masves ccs eon omens rns | nee om tee mer SE ND PRIA Novel Battleship Crate, in Which a Thanksgiving Turkey was Shipped to President Harding, from Cuero, Texas to Washington in a novel sort of crate [t was built to represent a battleship, with turrets and guns, and decorated with flags and pennants. The idea suggested by the’ fact that the Conference for the Limitation of Armaments was in session in Washington at the time, with the ques- tion of scrapping battleships occupying a conspicuous position. was MECHANICS KITCHENETTE CONTAINS MANY FEATURES Kitchenettes in the small mod- ern apartment must possess fea- tures that will work, elim- inate useless steps, and assist in the general saving of space. One of this type, now on the market, has incorporated in it many good points in this connection. In ad dition to the usual complement of shelves and drawers, the kitchenette in question includes a folding electric range with two burners, a built-in refrigerator, compartment for groceries, meat or milk, and also one for the de posit of table refuse. The ice box and compartments can bi opened from the rear, so that icé and food can be put in, and gar bage removed, without the kitchen, thus solving one of the housewife’s vexatious prob lems—the safe deposition of the food delivery. save a entering Which ice or SUNSPOTS CONSIST OF GASES COOLED BY EXPANSION The sun’s spots are cooler than the sur- rounding portions of the suriace of the sun, and the dark patches thus formed make them visible. Recently an American astronomer has mad several interesting deductions concerning them. It i wel known that gases are cooled by expansion, and in the there is an upward movement ol gas, producing an expansion and corresponding drop in temper ature. It is thought that the in crease in volume of the is 30 times or more. By making al lowance for the effect of heat be ing radiated into the sunspot: and for an increase of temper ature with depth, as would be es tablished by the radiation of the sun’s heat, it is estimated that the lower part of the vortex th sunspots must be in a region of extremel\ high temperature, probably over 20,000°C (36,000°F.). The temperature of the sun- spots is lower than the adjacent lumi- nous-gas envelope by 2,000 to 2,500°C., that on account of the tremendous drop in temperature produced, the sunspots may be regarded as the most powerful refrigerating engine known to 1 1S sunspots gas O, SO science.

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POPULAR MECHANICS Motor Coasting Sled Which Climbs the Hills under Its Own Power: For Coasting, It Rests on the Runners; for Climbing, the Wheels are Lowered to Support It, and the Engine is Started MOTOR SLED SAVES CLIMBING FOR COASTING PARTIES Coasting would be much more enjoy- le if it were not for the work of drag- zing the sled back uphill after the down- ill slide. With a new motor sled the climb is no longer necessary. This sled is equipped with a gas engine and wheels. For coasting downhill, the wheels are raised, and the sled rests on the runners. \t the bottom of the hill the wheels are lowered, the engine started, and the sled climbs back under its own power. HOLDER FOR TRANSPLANTING SAPLING TREES SAFELY The difficulty of transplanting young trees may be overcome by a invented transplanting receptacle. The hief reason for failure is that the nourishment stored in the soil about the roots is needed by the transplanted sap- ling to continue its growth. The recep- tacle is designed to transfer this soil with the tree. It consists of two curved pieces of sheet iron hinged together and fastened vith straps to form a bucket-shaped con- tainer. Two pins and four slides pass through slots, near the lower edge, to lorm a bottom. A circle is cut about the tree, and the surrounding soil dug out, so that the receptacle can be fastened about recently the column of earth and the pins and slides inserted. The tree is placed in a hole prepared to receive it, the slides and pins are «. removed, and earth is Left: How the Soil about a Tree is Removed for Transplanting. Right: Method of Attaching the Receptacie tamped in to the level of the first which is then unfastened. This is re- peated until the hole is filled, when the receptacle is withdrawn from the ground and the soil packed firmly about the roots hiwelLl DUCKIE, @ The U. S. Bureau of Mines is experi menting in the Nevada gold mines in an attempt to prevent or minimize the dan- ger of rock bursts in deep metal mines, by the use of the cement spray gun.

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A Street in the “Bungalette” Village Which will Accommodate 500 Motorists When Completed: At the Extreme End of the Street, on the Right, can be Seen a Store Which was Erected Expressly for the Conven- ience ot the Villagers. When Finished, This Street will be Paved with Crushed Stone “BUNGALETTE” CAMP FOR MOTOR TOURISTS By JOHN ANSON FORD ERE is the latest idea in camps for motorists. An Oakland, Calif., con- cern is spending no less than $80,000 in erecting “bungalettes” on an eight-acre tract, to be let to motoring tourists by the night or for any longer period “up to fifteen years” (as the management jok- ingly announces), which is the length of the lease on the land. These simple resi- is commonly offered by an ordinary tent These bungalettes are of two type some with one room and some with two rooms. They are built entirely of wood and are equipped with sinks, running water, electric lights, two-burner ga plates, etc. They rent for $20 to $35 pet month, and at corresponding rates for shorter periods. A third type of structur is designated as a “shel ter house,” and consists of a shed, about 9 ft Square, open on_ two sides, furnished with a combination table and benches for four persons and a two-burner gas plate. These shelte: houses rent for 75 cent per day or $4.50 per week. The Building on the Left Is One of the Sanitary Toilet Houses of the Village, While the One on the Right Is a Laundry. Both Struc- tures Possess Modern Plumbing dences are designed to take the place of tents, and while their furnish- ings -are meager com- pared with regular houses, they offer con- siderably more in the way of conveniences than 416 Another View of the Village Street, Showing Some of the Houses Which Contain Electric Lights, Running Water, and Two-Burner Gas Plates

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POPULAR MECHANICS 413 All rates quoted include gas for cooking, to travel by automobile and stop in auto as well as the use of community laundries, camps. which are equipped with sanitary tubs When all the structures in the Oakland with running hot and cold water. The bathhouse, which occupies a central location on the grounds, is equipped with enameled tubs and is piped for hot and cold water. Sanitary toilets are also conveniently located. Construc- tion of the bungalettes and shel- ters began in the late summer last year, and the demand for them proved so great that the owners decided to double the number of structures to be erected. As soon as they have erected enough shelters and houses to accommodate the teady stream of incoming tour- ists, they propose to erect a dance pavilion where entertainment will be provided evenings and on ; a is ais rainy afternoons. ae ee I SS te It has been found that a sur- Om af Ge “Shelter Houses” of the Village, Which Is Open on rising demand fe accommoda- wo Sides: It Has a Combination Table and Benches Accom- prising : le . d ‘i mat modating Four Persons, and Also a Two-Burner Gas Plate tions of the kind provided here, exists among traveling salesmen, who evi- camp have been completed, it is expect: dently consider it more economical to mo- that between 400 and 500 cars will b tor to this camp with their wives than to. parked there nightly. In view of th put up at hotels. Here they can set up shortage of houses, many new arrivals it housekeeping at very little cost,and in the’ the vicinity of Oakland have turned t week or two consumed in “doing” the these structures as temporary homes Bay District, the salesmen’s wives en- parking their automobiles close by thei: oy sight-seeing, shopping, etc. Another bungalettes, and preparing to stay fo: class of patrons are members of theatrical several weeks or months. The camp troupes. Already a considerable number located close to a public school, and se\ who are on the Pacific-coast circuit have’ eral “tenants” have already enrolled thei: found it more enjoyable and economical’ children there. SMALL TRACTOR ATTACHMENT disking, cultivating, and dragging, the: IS PLOW AND WEED KILLER is now being manufactured an attacl ment for a standard small tractor, ot Originally designed as a weed killer, but which there are a large number now also adapted to the work of plowing, in use. The tractor has a belt pulles . — which is removed, and on it shaft the attachment is mount vertically, so that through gears as in an ordinary drill press, it cutting knives at the bottom ot its spindle can be rotated at 5" r.p.m., through a 2-to-l gear re- duction to the motor of the trac tor. While the ordinary plow merely buries the weeds, without destroying them, the whirling knives of this attachment cut t! weeds to pieces. It is speciall effective on wild, rank grass which on the northern prairie ae : is so prevalent and harmful. It Attachment for Weed Killing and Plowing, Designed to Fit a . “od P ; na ale oe ' Small, Widely Used Tractor quickly improves any weedy s

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418 POPULAR ELECTRIC SEALING MACHINE IS SAFE AND ECONOMICAL A sealing machine, in which the wax is electrically melted, and which is intended to meet the requirements of bankers, . brokers, jew- elers, and large com- mercial insti- tutions in the sealing of val- uables, has made its ap- pearance. The machine can be attached by a cord to any light socket, and operated at a cost of one- half cent an hour. In op- erating, 2 spring holds the sealto one and _ the wax is re- leased by a small lever, after which a downward pres- sure on the apparatus brings the seal into position for making the impression. The use of the appliance gives protection against the fire hazard, to say nothing of the avoidance of burnt fingers and “mussy” seals. side, @ Because of the scarcity of timber for use as props, a South African coal-mining company, which produces nearly 40,000 tons a year, has planted 250 acres to trees, and another equal amount of land is now under preparation for the same purpose. MECHANICS SLOUGH BECOMES SEWAGE CHANNEL IN BIG SYSTEM By creating an inlet to a slough, and ex- cavating a uniform channel throughout its length, the city of Portland, Ore., has furnished an outlet for sewage for a large residential district including 40,000 city lots. The successful completion of the new channel at a total cost of $350,000 also makes unnecessary the construction of a trunk-sewer system that would have cost 3,500,000 dollars. The slough that was thus utilized branches off from the Columbia , River on the northern boundary of Portland. At low water it had no inlet, and conse quently there was no current, so that it could not be used to carry off sewage. Both the Columbia and Willamette rivers are several miles distant, and it was first planned to build a trunk sewer to empty into one of them. Then engineers hit upon the idea of transforming the slough into a branch of the Columbia. Six large dredging machines were em- ployed, nearly 1,500,000 cu. yd. of earth were excavated, and 25,000 yd. of rip- rap placed. A uniform channel, 150 ft. wide at the bottom, was dug for a dis tance of 214 miles, and dikes were placed along it to protect the adjacent drainage districts. When the project was first proposed there was much opposition to it on the ground that there would be too much current during high water and not suffi- cient current to carry off the sewage dur- ing low water. Tests of the velocity of the water, as the project was nearing com- pletion, proved that these fears were groundless, and that the channel is a prac- tical solution of the sewage problem in the district that it serves. Left: in the Background. Right: The Mouth of the Drainage Canal in the Foreground Emptying into the Columbia River, Which is Seen i A Section of a Dike with Water Gate, Built along the Drainage Canal to Protect the Adjacent Farm Lands during High-Water Periods

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POPULAR MECHANICS RAILROAD USES MOTOR TRUCKS ON HETCH HETCHY LINE The Hetch Hetchy Valley reservoir, in Yosemite National Park, which is to sup- ply water to San Francisco, is reached by a short railroad, circling up through the mountains, over which automobile trucks of a novel type are operated. They are equipped with flanged wheels, to fit the rails, and special bodies. For handling mail and express, the bodies are inclosed partly with solid sides and partly with heavy wire net. Two sliding doors in the sides are used in loading, and another door gives access to the driver’s compart- ment. There the dashboard is raised and placed at right angles, part way up the steering post, to support a brake ratchet. The steering wheel, being useless for its ordinary purpose, operates one of the three brakes made necessary by the many steep grades along the line. One truck is equipped as an ambulance, with a stretcher hung under the top. Others are arranged for handling tourist traffic. “TREE SURGEONS” AIDED BY PORTABLE OUTFIT “Surgical instruments” consisting of a cutter, or reamer, having 11 small circular saw blades, and ordinary steel bits, have been introduced: as an aid in removing the dead and diseased wood from trees undergoing treatment. These tools are Above: One of the Truck Cars Used for Car- rying Mail and Express in the Hetch Hetchy Valley. Left: Interior of the Combination Mail and Ex- press Car. Right: The Dashboard is Raised to Accom- modate a Brake Ratchet operated in a portable electric drill, which is driven by a gasoline engine and 42-hp. generator. As the total weight of the ap- Above: Portable Electric Drill! Showing Special Reamer. Below: Treating a Diseased Tree with the Portable Electric Outfit paratus is 120 Ib., it can readily be transported to any tree requir- ing attention only about @We want all our readers to write us freely and often whenever they wish ad- ditional information on articles published in this magazine. Address Bureau of In- formation, Popular Mechanics, Chicago.

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MOVING-PICTURE FILM PREPARED ON RUNNING TRAIN By JACK A. BRISTOL AUGHT short on time with a New York opening date booked, and fac- ing a huge loss for each day’s delay, a moving-picture producer made arrange- ments to edit, title, and cut the play en route between \ngeles and the east- ern metropolis recently. With a special Los fa i " me. Projection of Movies aboard a Train in a Specially Equipped Car: The Pro- — on the Table, and the Silver creen, were Rigidly Built In to Elim- inate Flicker car equipped as a laboratory and attached to a limited train, the work was found entirely practical even while speeding eastward at a mile a minute or more. The equipment in the special car consisted of all the cutting apparatus ordinarily used in a laboratory, in one end, a silver screen rigged across the other, and a projecting machine about “amidships” of the car. Both screen and projector were rig- idly fastened to the car, and thus, while there was the same motion and vibration attendant upon all moving trains, it was apparently so synchronized that the pro- jected pictures were sharp and clear at all times. With this arrangement, more than 100,000 ft. of film were run off to enable the film editor and his assistants to select the 12,000 ft. needed. Electricity for the heavy are lights in the projector was furnished by a dynamo car running ahead of the laboratory car, 420 from A steady available at all and utilizing high-pressure steam the locomotive for its operation. supply of current was times, regardless of train speed or whether the train was in motion or not, thus enabling the projector to function without interruption, a feat impossible with the ordinary belt- driven equipment. Twenty-eight heavy steel containers carried the original film, whic remained in the “cans” all the time it was not actually in use. Editor and cutters worked continuously, stoppin only for meals and fo a few hours’ sleep at night, and on these oc casions every scrap of film was returned to its proper container. The work was entirely suc- cessful; and by the time the train arrived in ee Sam, SO Cutting End of Car, Where Film Editor and His Assistants Trimmed 100,000 Feet of Film to 12,000 Feet While Traveling from Los Angeles to New York New York the film was finished and ready for delivery. @ Popular Mechanics Magazine does not publish the name of maker or seller of any device described in its pages, but thi information is kept on file and will be furnished free by addressing our Bureau of Information,

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Luxurious Motor Car Made to Order for an Indian Maharajah for Use in Welcoming the Prince of Wales on His Recent Visit to India: The Body is Painted a Mauve Color and Striped with a Broad Gold Band. The Interior Has Mother-of-Pearl Inlay and Solid-Silver Fittings LUXURIOUS AUTOMOBILES FOR INDIAN ROYALTY HEN royalty, and especially Indian royalty, puts in an order for some- new and startling in motor cars, it »e satisfied with nothing that doesn't take the breath away for luxury and vel features. Two cars were manufac- ured recently in record time by a famous sritish firm for the Maharajah of Bharat- ir, in order that that potentate might roperly welcome the Prince of Wales on his trip to India. The cost of the open hody was a mere $15,000, not including which cost about more. The big sedan- nousine set the maharajah back nly $40,000, but he figured it was orth it, considering the amount mother-of-pearl inlay work he tt and the solid-silver fittings. The inclosed body, painted iuve and striped with a broad Id band, is entirely finished in- ide with solid mahogany and in veneer, inlaid with mother- p f pearl. News travels slowly to e Orient and they have not yet eard of prohibition. Therefore cabinet at the the front over hich is a table. Two small fold- ig doors give access to a large ilver cigar box, while a drawer below, lined with plush, contains glasses for the royal cocktails and rickies.” In the center of this cab- inet are mounted a speedometer and clock. On either side of it are auxiliary seats which fold away completely and appear simply as noe = 311 1 ii | he chassis, 10.000 he car has a large iCK of seats, mahogany and satinwood panels, heavily inlaid. On either side of the back settee, which is upholstered in mauve silk, shot with special silver design, are cabinets of similar finish. The one on the right con tains two very large vacuum bottles while that on the left is fitted with silver- topped cut-glass toilet bottles, manicur« set, and brush and comb. On each of these cabinets is a dictograph with solid- silver mouthpiece, while the push buttons for calling the driver’s attention to the E oa - = — =— Interior of the Limousine, Showing Part of the Solid-Mahogany Finish, with Mother-of-Pearl Inlay: On the Floor is Seen the Electric Radiator, and the Silver Flower Vases are Also Shown 421

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POPULAR MECHANICS Second Automobile Made for the Indian Maharajah in Honor of the Prince of Wales’ Visit: The Body Is of Aluminum, Painted a Canary-Yellow, with Light-Blue Facings, and Is a Streamline Sporting Type Accommodating Five Passengers. passengers’ wishes are of gold. The win- dows, which are fitted with special raising and lowering devices, have both blinds and curtains, while ventilation and cool- ing breezes are supplied by an electric fan, high up over the window behind the driver, and by two large glass ventilators in the roof. A small electric radiator is installed for use in chilly weather. The usual equipment of electric lights inside and out has been supplemented with ornate shades and domes, and among the other fittings fluted silver flower vases and a large swiveling search- light in front of the radiator. The open body is of aluminum, painted canary-vellow with light-blue facings, and are Interior of a Large Building, the Framework of Which is Composed of Tubing: The Joints were Made by Welding, So That the Completed Frame Is Really One Piece, There Being No Rivets, Bolts, or Screws The Swivel Searchlight is Plainly Shown sporting type for five It has a bulbous tail in which are four separate compartments containing a water tank, an ice box, a silver washing bowl with complete toilet fittings, and a special type of automati- cally disappearing dickey seat. In the tonneau are two mahogany thirst-quench- ing cabinets similar to those in the sedan The near front seat slides, revolves, and tips forward, while both front seats have collapsible backs which can be made into comfortable beds. The disappearing top is made of the finest alpaca, to match the blue-leather upholstery, as are the side curtains. This car also has a large swiveled searchlight. is a streamline passengers. FRAME FOR LARGE BUILDING MADE OF TUBING The superior strength of tubing, under certain stresses, is applied in the construction of a shop building in Texas. Great- er strength and rigidity are obtained by welding the ends of the tubing at the joints instead of us ing rivets, bolts, or coup lings. Also, by this means, a simple and trim structure, free from dust collecting and easily accessible for paint ing, is obtained. -The sides and are CO\ ered with corrugated iron. The dimensions of the building are 50 ft. in width by 100 ft. long. recesses roof

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POPULAR MECHANICS 42: (~

The New Weed and Insect-Exterminating Machine, Showing the Combination of Roller, Hood-Inclosed Burners, and Saws, behind Which are Placed the Cremating Furnace and Distributor: to Be One of the Most Important Developments in Agricultural-Implement NEW MACHINE EXTERMINATES WEEDS AND INSECT LIFE If a recently deveioped farm machine fulfills expectations, a large part of the loss to farmers from weeds and insect can be eliminated. The processes used are not new, in themselves, but their practical combination has been described as one of the most important develop- ments in the history of agriculture. The entire mechanism is operated by a small casoline engine, mounted on the frame. \ front roller crushes all vegetable matter and is followed by a hood, which controls the flames from a row of oil burners, so that the fire cannot spread. This cremates all vegetable and insect life, and prevents germination. Next, close-set saws cut the soil and roots, which are then carried up an incline to a spiral cutter, where the ‘oots are further cut. They are then car- ried to a set of sieves which separate roots nd soil by pressure from an air fan. Ref- use is blown back into a furnace and con- sumed. The soil is distributed in the field ibsolutely free of vegetable and insect life. The machine works a strip 40 in. wide and easily covers eight acres a day. pests

COIN-OPERATED AIR-HOSE SUPPORT FOR GARAGES A coin-operated air-hose support, for garages and filling stations, has recently been invented. It consists of a hollow pipe standard with a tilting arm at the top. The air hose extends through the arm and will not reach a machine unless

This Machine is Said History the arm is brought to a horizontal posi- tion. Normally, the arm is held nearly vertical by a counterweight and by a catch at the fulcrum point. <A rod, at- tached to the /) catch extends

This Hose Up off the Sidewalk When Not in Use. Its Construction Is Simple and Strong Coin-Operated Support Keeps the Garage Air down through the standard and ends in a coin receiver. When a coin is in serted in a slot in the standard, a lever can be pressed against it to release the catch.

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NEW PRINTING OUTFIT USES TYPE STRUNG ON WIRES pate » the time of Benjamin Franklin considerable quantities of office station- nat “the laborious hand press, the’ ery, might find it a profitable investment. The familiar printers’ “stick” is done away with, and the type is “set up” by being strung on 1 steel wire, and fed by gravity from a_ special type case. Letterheads, envelopes, statements, in fact any character of work, may be done, either through use of printers’ ink or by means of a ribbon at- tachment. The press is worked by hand, with an automatic Ordinary Printers’ Job Form Set Up in the New Manner The Printing Press Has a Stack of En- velopes in It printing indus- try has evolved but slowly. The present day has seen the devel- opment of the type-setting Above: The Type Rack, Show- ing the Method of Stringing Type from the Rack onto Form Wires by a Simple Pressure of the Thumb. Right: Type Dis- tribution, with Type Pinion Ready to Receive and Distribute Type from Forms After It has been sed machine which produces type in uniform slugs, but the individual type remains the same. Now a a yn la., inventor has built a printing plant so simple in operation that any firm, using any 424 paper feed if desired. The press and paper feed are an adaptation of the old flat bed-press idea, and the work turned out can not be distin guished from ; = regular print- Form on the Press Which is '"8- he type Equipped, in This Case, with setter is the Automatic Paper Feed of Flat- most interest- Bed Type " - ing part of the invention. \ touch of the operator's thumb releases a metal type slug and strings it on a wire. A little practice gives the right spacing. When a line is strung it is removed from the setter and placed in the form. The distributor, also, is an interesting bit of mechanism, which allows rapid distribution of the type afte using it. @ Our Bureau of Information will answer all questions regarding articles appearing in this magazine. ‘int Lid

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POPULAR MECHANICS A Real House Built on iy Truck Chassis Is the Travel- ing Home and Business Establishment of Two Ohio Men en Route to Florida, Who are Paying the Ex- penses of Their Trip by Mak- ing and Selling Taffy and by Giving Moving-Picture Shows in the Small Towns along the Road Which Have No Movie Theaters et COMBINED HOME AND BUSINESS ESTABLISHMENT ON WHEELS Recent years have produced many motor vans for touring, but the one in hich Frank Griswold, of Willoughby, Ohio, is traveling to Florida is distinctly ovel. The body, built on a truck chassis, is the appearance of a real house and is elaborately decorated, with stained glass nd painted scenic panels in the doors. he interior is well furnished for comfort- ble living, and in addition is equipped ith a stove, for making candy, a moving- icture machine, and a small pipe organ. .ccompanying the owner is D. Roberts, n expert taffy maker. The men are Lyi ig the expenses of their trip by sell- ig taffy and giving picture I have no two shows in regular owns” which movie ] eaters. SECTIONAL BUFFING BRUSHES HAVE INTERLOCKING PLATES \n eastern firm has placed on the mar- ket a sectional buffing-wheel brush, which is made in three materials—wire, horse- hair, or fiber. The outstanding feature of the brush is an interlocking arrangement, achieved by having the faceplates con- structed with corrugated Surfaces. When two sections are properly placed together, these corrugations intermesh, thus pre- “ear Tits cluding any possibility of slipping. The half-inch shaft widths, hole de- made in diameter oi sections are and with any At the Left is Shown a Single Section of the Inter- locking Wheel, While at the Right are Seen Numerous Similar Sections Joined to Make a Large Wheel sired, so that buffing wheels of built up to fit classes of work. The wheel was specially designed for tire and rubber manufac- turers, and is said to be efficient and eco- nomical for tire-repair work of all kinds. various sizes can be different

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126 POPULARITY OF MYRTLE WOOD REDUCES LIMITED SUPPLY The growing popularity myrtle, as a wood for the manufacture of novelties, special furniture pieces, and interior panel Grove of Myrtle Trees in Coos County, Oregon, work, calls attention to the fact that it is found, in commercial quantities, in only one place in this country. It is estimated that about 687,000 ft. are available in Coos County, in southwestern Oregon, and that the demand will soon require a cut- ting in excess of the production. Myrtle very slowly, a tree of the greatest about 12 ft. in diameter and 100 ft high, requiring about 300 years to de- velop. Most of the trees in Oregon are from 18 to 48 in. in diameter. The wood is greatly prized because of its beautiful graining. No two pieces are ever exactly alike, and matching is impossible, which adds to the manufacturing cost. Its cost is also increased by the fact that it will not float in water. Because of this, trucks erows size, Bowls Turned from Myrtle Wood: This Wood has Become Popular for Such Purposes Because of Its Beautiful Graining or trains must be used to transport the logs to the mills. This is, of course, a much more expensive method of handling than floating them down the rivers, as is commonly done with other kinds of timber the Only 1 Place in the United States Where They are Found in Quantities Suf- ficient for Cutting on a Commercial Scale POPULAR MECHANICS INTERESTING DEMONSTRATION OF RADIO-WAVE VELOCITY The tremendous speed with which elec- tricity travels was demonstrated in an interesting way at a recent gathering in — Washington, D. C. The evening had been spent in’ listening to a_ radio concert coming over the Allegheny Mountains from the station of a1 electrical company it Pittsburgh. Just befor 10 o’clock, the time sig nals sent out by Arling ton, just across the Poto mac from Washington were picked up on th: long wave by Pittsburg! and retransmitted on the short wave used for broadcasting music Washington is almost i the shadow of the great steel towers of the Arlington station, and the direct signals were so strong that the) forced themselves on the receiving se tuned for Pittsburgh. Both the origina and the retransmitted signals were ther« fore heard at the same time and identi fied by a slight manipulation of the tun ing knob. At the receiving station \Vashington, a telephone receiver wa ittached toa suiaaiin iph horn, permittin all present to listen at the same tim The signal returned from _ Pittsburs seemed to come in just at the same tim: as the one received direct from near-b) \rlington. It was then figured that, there were no perceptible delay at Pitt burgh, the signal took only .002 of a sec ond for the round trip. The direct sig nal was just coming out of the large en: of the horn at the moment the signa relayed back from Pittsburgh was start ing in at the small end. It was also com puted that, if the telephone receiver at Pittsburgh were connected to the trans mitter through a tube carrying the soun by air through a distance of seven iaches the signals reaching Washington fro Pittsburgh would be such that the vibra tions of the musical notes would be e actly out of step, and the two signal would tend to weaken each other. @We want all our readers to write u freely and often whenever they wish ad ditional information on articles published in this magazine. Address Bureau of In formation, Popular Mechanics, Chicago

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UTAH MINE Right: Outcrop. of Vein of Jet in Wayne County, Utah, the First Deposit of This Mineral Discovered in the United States. It is Now being Mined as Shown Below, Where the Vein is ee and a Miner Is at Work im It (# aia Below: Auto Truck Full of Jet Slabs from the Utah Mine, Accompanied by a Number of the Men Interested in Its Devel- opment WA] HAT v deposit to be developed in the United States is now being successfully mined in Wayne County, Utah, where re- cently mineralogists discovered the larg- est commercial body of the mineral known to exist in the world. Singularly, discovery of the jet was accidentally made by a party of miners engaged in assess- ment work for a copper company. The work of mining the jet began late in the summer of last year, and with financial hacking assured is expected to develop into great proportions. For ages jet has been prized by barbaric and semicivilized peoples for use in ornamentation, and the taste has sur- vived. The possibility of carving the min- eral into ornaments of rare beauty and delicate workmanship and of giving the black mineral a beautiful velvety polish, is believed to be the first jet GIVES PROMISE OF U. S. JET INDUSTRY By FREDERIC KINNEY Above: Two of the 2 Miners at the Jet Vein with Some of A See | , se , the Jet Slabs in Sacks Ready for 7 2 ; Shipment has made deposits of jet widely sought for. Proof of its age-long use is given by the discovery in barrows of the Bronz \ee of beads, buttons, rings, and other personal ornaments made from the min- eral. Its occurrence in Britain is men- tioned by a Roman writer, and it is cer- tain that it was used in pre-Roman times. The early supply was probably obtained from the Yorkshire coast, near Whitby, from mines which still supply the world’s markets with the much-prized mineral. Spanish jet is said to be deficient in lus- ter and hardness. Cannel coal from Scot- land is occasionally used as a substitute for jet. While the origin and nature of the jet deposits in Utah are, of course, a matter of conjecture, there is good reason to be- lieve that during the geologic age, when the Henry Mountain Range was thrust

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128 POPULAR above the surrounding territory, a great furest was covered with hundreds and perhaps thousands of feet of overburden. The pressure of this overburden flattened out trees that were probably a foot or more in diameter to a thickness of from 4to 6in. Squeezing out of the sap, the closing of the pores of the wood, and the tremendous heat and pressure, fossilized the vegetable matter and converted it into the mineral known That the de- posit was once a forest is apparently proved by the fact that, in the large slabs of the mineral exhibited in the office of the state mineralogist, is easily detected the fibrous character of the material. The Utah deposit is overlaid by a tough as jet. MECHANICS fireclay substance about 6 in. thick. The remainder of the overburden is soft and is readily slushed off the mineral by the use of water. Despite the tough and firm character of the jet, it is easily mined with pick and trowellike blades, the min- eral being cut out in slabs of varying length and thickness, averaging, however, 12 to 14 in. in length and 4 to 6 in. i width. At the present time, the work of mining the mineral is more or less crudely done, but it is the intention of the owners of the decidedly valuable deposits soon to install modern machinery and develop the indus try into the largest of kind the world. In in its FUR DURABILITY MEASURED BY NEW DEVICE N order that a standard test of fur durability may be had, and that vari- ous furs, or the same furs differently treated, may be fated or at will. In this way the fur samples are subjected to the same tests, and their durability definitely recorded. From time to time standardized on _ the basis of their wearing qualities, there has been recently devised at Cor- nell University the ap- paratus shown in Fig. 1 It consists of a hammer, and a slide, which be operated upon a fur sample placed in the position indicated by B. The weight of the slide is known, as is also the force of the impact of the hammer. When the motor is set in motion, the fur sample at B is alternately rubbed and beaten. The force of the hammer and the weight of the slide can be can have Machine for stroke varied Fig. 1—The “Attritiometer’” Which Tests the Dura- bility of Furs for Standardization Purposes Consists of the Following Parts: M, Motor; H, Hammer; B, Block, upon Which the Fur Sample is Placed, and S, Slide That Rubs agains’: the Sample Fig. 2—Four Blocks of Fur Samples Which been Removed from the Testing Microscopic Note Breakdown of Hairs the block containing the sample, Fig. 2, is re- moved and the fur ex amined under the micro scope, to note the first signs of breakdown the individual hairs. When these indications of disintegration are noted, the sample is re- moved, recorded, and a second sample intro duced. Or the sample may be left in the test- ing device until the in- dividual fur hairs break off. Various tests can thus be applied. By means of these tests it is also pos- sible to distinguish between the wearing qualities of the same kind of fur which has been subjected to different treatments, such as plucking—that is, picking out the overhairs—dyeing, clipping, ot Examination to coarse so forth. Tests in this “attritiometer” have also been found useful for rating the wearing qualities of clothing fabrics. In such the material to be tested is stretched over the blocks which are used for fur samples, or the fabric may be fastened in a small crumpled mass to the block, or arranged in any way which the test may call for. so-called cases @ Whenever you find that you wish to know more about any article in the maga- zine, write our Bureau of Information.

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POPULAR AERONAUTICAL CHAMBER OF COMMERCE ORGANIZED The organization of the air-craft indus- try into a national body, recently effected, step which, it believed, will greatly hasten the development of Amer- ican aviation. The organization, com posed of approximately 100 charter mem- ers, representing practically every ele- ment of the industry, such as designing, constructing, operating, etc., has for its objects the development of the market for airplanes and the increase of their use by individuals and corporations. It will act me” is as a credit bureau for its members, and as a board of arbitration in case of dis- putes; assist in mapping of air lanes, and in all ways help to promote the industry. HANDY LUBRICATING DEVICE WORKS WITH AIR PRESSURE \ portable pressure-lubricating device is been designed specially for dispensing grease accu- rately by measure with the least possi- ble effort, and with the elim- ination of waste from leakage. It is particularly adapted for use in garages and greasing- service sta- tions, where air pressure is available. It consists of a tank, with a capacity of 70 lb. of grease, which is placed under

air pressure <_ _. that forces the grease hrough a hose to a double-acting weigh- ing nozzle, which delivers 1% Ib. the troke. to @At Montgomery, Ill, the Burlington railroad has completed a sheep shelter, said to be the largest in the world, con- sisting of seven barns, each 450 ft. by 130 It.; a 1,000-acre pasture; hay, grain, and feed barns, and a_ 100,000-bu. elevator. rhe plant accommodates 70,000 sheep. MECHANICS 425 DEVICE TO PREVENT DAMAGE OF OBJECTS BY MOISTURE For the purpose of preventing the pres- ence of moisture in sufficient quantitie art, musi- to do harm to works of cal instru- ments, or perishable foodstuffs, a simple little device has been placed upon the mar- ket. It in the form of a perforated cylindri- is cal container for a chemical that is harm- less, odorless, and nonin- flammable, and which

when placed in a piano, or containing any instru- ment, or in a wall case, : protects these objects from excessive mois- ture. It in a similar

a case

acts manner o1 brass and silver articles, preserving them trom tarnish and corrosion. The device is made in a number of sizes for the vari ous purposes. KEY ATTACHMENT SAFEGUARDS LOCKS FROM BEING PICKED To make the picking of a lock impos- key sible, an attachment that holds a securely in a key- hole after the lock is turned, has been designed. A small clamp, adjustably secured to the stem of the key, in cooperation with a plate that inserted in the keyhole, after moving the _ bolt so to lock the door. makes it im- possible to turn the key from the outside, or to force it out of the lock. Thus it is not only practically impossible to pick but no counterfeit key can opea it. is

as

lock the be used

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130 POPULAR GAUGE TESTS COMPRESSION LOSS IN MOTOR CYLINDERS \ny means of determining by test, not only the amount of the loss of compres sion in the cylinder of a gasoline engine, but also the cause of that Loss, whether past the piston or the will be of valuable assist valves, ance in directing the work of the repair man. A recently patented compression-loss makes this possible. It does more than that, for it shows what percentage of the theoretical compression is lost by leakage past the piston, and what percent- age is lost by leak- age past the valves. The dial of the gauge is gradu- ated to give read- ings test gauge ry as close as a fraction of one per cent. The instrument is small, weighing only a few pounds, and the time required for testing a motor is approximately five minutes for each cyl- inder. MECHANICS POLAR SHIP “QUEST” SAILS FROM RIO DE JANEIRO \fter a series of tests that proved that all the machinery and equipment were in perfect order, the “Quest,” with the polar expedition in command of Sir Ernest Shackleton, sailed Dec. 17, 1921, from Rio de Janeiro, bidding farewell to about its last contact with civilization before it reaches the southern polar region. On the 19th, Sir Ernest telegraphed London, “Our engines are running perfectly. There is a fair wind. All well and looking forward.” The added weight of taken aboard at Rio caused the ship to ride low in the water. stores ROADS SPRINKLED IN WINTER TO MAKE AN ICE SURFACE Street sprinklers are a familiar sight to the city dweller in summer, but up in the northern lumber camps the roads are sprinkled in winter. Logging roads are usually temporary affairs, slashed through the woods and swamps, with no attempt at surfacing or anything more than clear- ing the right of way. But, as the log- ging is done in winter, it is a simple mat- ter to maintain a smooth surface of packed snow and ice. A large tank, mounted on a sled, is driven over the roads. From it streams of water fall into the tracks and quickly freeze. This makes a smooth ice surface, over which the big bobsleds, loaded with five tons or more of logs, are easily hauled by two horses. | em <¢ pert One of the Bobsled Road Sprinklers Used in the Northern Lumber Regions during the Winter Months, to Keep the Surface of Logging Roads Ice-Coated, So That Huge Sled Loads of Logs may be More Easily Hauled

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POPULAR MECHANICS 431 PUMP LINED WITH RUBBER HAS GREAT DURABILITY Soft resilient rubber has been success- fully used to line pumps, because acid cor- rosion, or abrasion from operation for a sufficient length of time ful- ly to demonstrate their wearing qualities. rough substances passing through the pump, is practically eliminated by the rubber lining. The pump is designed for op- eration with either a belt drive or by direct con- nection to an electric mo- tor. Both bearings are mounted outside the pump case and are of the ring-oiling reservoir type. [It is said, that the me- chanical and hydraulic ef- ficiency of the rubber- lined pump is equal to that of the old-style metal-lined pump of cor- responding size. Al- though a new pump, there are many of this type that have been in Rubber-Lined Pump Opened, Showing the Resilient Interior: Four-Inch Size, and Smaller, the Lining is Attached to the Pump Casing; in Larger Sizes the Lining Is Removable In Pumps of ALL NEW YORK CITY TRAFFIC GUIDED FROM ONE CENTER In all large cities the problem of traffic control is becoming constantly more dit- ficult of solution, but nowhere so much so as in New York City. Plans, such as the control towers on Fifth Avenue, de- cribed in Popular Mechanics for May, 1920, have been more or less successful, but as yet nothing has been attempted of such wide scope as the present plan to control all traffic from one central station in Times Square. It is ——— planned to install red, green, and yellow search- lights conspicuously, that will control simultane- ously all the traffic north and south, as well as the cross-town traffic, east and west, all operated by a single switch in Times Square. A traffic director, seated in the center of the city, by the pressure of a button will cause a number of red lights to flash that will stop all trafic moving in one di- rection, while green . ° oo ? lights will govern the : STEEL TANKS MORE DURABLE IF FEWER PLATES ARE USED Building longitudinal increase the tanks with has been strength of the steel only four found to container, plates as well as reduce the liability of leakage According to engineers, these tanks are 50 per cent stronger than the ordinary type with 10 to 14 plates, and cost much less, as there is a great decrease in the amount of riveting necessary and a corresponding increase in production. oe xa ore na a — —s traffic in the other direc- tion. Steel Tank Having Only Four Longitudinal Plates Efficient for the Storage of Oil Than Those of Ordinary Make Which has Proved More *

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POPULAR AUTOMATIC PIPE SMOKER FOR TESTING TOBACCO Testing the cool-smoking properties of tobacco blends, and “breaking in” new pipes, are now performed with the aid of a smoking machine latel\ developed in London, Eng. The apparatus is operated by electricity, and has adjust- ments with which it can be regulated to “puff fast” or to consume the contents of a pipe as slowly as desired, thus providing any manner of smoking experiment. LIGHTWEIGHT PORTABLE CRANE LIFTS 30 TIMES ITS WEIGHT For lifting weights of any kind, wherever they may happen to be deposited, a very light and easily transported hoist that acts as a crane is in use in France. It is com- posed of two similar tripods, with strong steel legs, which when opened out are braced in any desired position by chains between them. On top of these tripods are carcasses a iB Light, Portable Lifting Crane, in Use in France: It Is All Steel; the Tripods are Braced by the Chains be- tween Them, and Held in Any Position. MECHANICS steel supports and connections for a light latticed girder, supporting on its top a movable carrier to which is slung the block and tackle that does the lifting. The tripods are placed on either side of the load to be lifted, and are first spread so that the girder can be clamped in position by hand. The legs can then be arranged and braced with their chains, to suit any conditions of the work to be done. This apparatus complete, with a lifting capac- ity of 2,200 lb., weighs only 92 Ib., and one with a capacity of 3,300 lb. weighs 115 pounds. CULTIVATION MADE DIFFICULT BY HARDENING OF FARM SOIL The annual report of the Bureau of Plant Industry reveals the fact that some of the most fertile irrigated land in the West has become unproductive by reason of the hardening of the soil to such an extent as to make cultivation exceedingly difficult. It is believed that this harden ing is due primarily to the sodium salts carried in the irrigation water, and experi ments with corrective applications of cal- cium, iron, or other salts are now being undertaken. @ Road construction, with Federal aid, throughout the country for the past four years, has averaged in cost per mile: graded and drained roads, $8,115; sand clay, $8,250; gravel, $10,400; macadam (water-bound), $17,320; macadam (bitu- minous), $31,300; bituminous concrete, $30,350; concrete, $39,540, and_ brick, 49,570 dollars. The Girder Clamped to the Tops of the Tripods Supports the Block and Tackle for Lifting Loads About 30 Times the Weight of the Complete Crane

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POPULAR MECHANICS 433 PEPPERMINT ROOTS PLANTED BY AUTOMATIC MACHINE Planting the roots of the fragrant pep- permint crop has heretofore been accom- plished by hand, but a comes three-quarters of the entire world’s peppermint and spearmint-oil production. lately designed machine is available, which takes the place of 16 men. The mint planter has an endless-belt arrangement driven by the front wheels of the machine, which feeds the roots to . hopper. From the hop- per, the roots fall into a furrow, which is dug and then covered by the planter. The inventor manages a 10,000-acre mint farm in Michigan, from which state, _ to- vether with Indiana, AUTO-RADIATOR TRUSS AFFORDS QUICK AND CHEAP REPAIR A simple, quick, and inexpensive repair for broken or leaky automobile radiators is now available. It consists of a long bolt which is attached in front of the radiator by means of hooks, at each end, which fasten over the front-fender brackets. Tightening the nuts pulls the ends of the frame toward the center and relieves all strain. The result is that cross members are kept from breaking, or if already broken, are pulled together and need not be replaced. It also prevents the break- ing of ears, and leaking. The truss can “DEATH-CROSSING” HAZARD CONTAINS TRIPLE RISK Dangerous crossings are numerous, but one of the worst is to be found near Ot- tawa, Ill. The crossing Machine for Planting Peppermint, Showing the Endless Belt Leading into the Hoppers, below Which can be Seen the Tool That Makes the Furrow be attached to a machine in a few min- utes, using only a pair of pliers or a wrench, and can easily be removed. The Radiator-Repair Bolt, and, Above, the Method of Attaching It to a Broken or Leaky Radiator safely passed, the autoist finds a sharp incline directly ahead, leading to the bridge. Coming down from the other end of the bridge, there loom in his path the interurban tracks. possesses an almost fiendish design, there be- ing three risks for the driver, which are greatly magnified should he prove to be careless or incompetent. These three are a railroad crossing, a high and narrow canal bridge, and an interurban right of way. A steep hill, the descent of which is a task in itself, pre- cedes the railroad haz- ard, and if the railway is Triple-Hazard Crossing with Railroad Tracks in Foreground: Metal Sign with Red-Glass Center Erected to Warn Motorists Insert Shows

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CIVIC FEATURES THAT PROMOTE THE COMFORT One of Two Attractive Gateways, Erected at Milford, Illinois, Where the Dixie Highway Enters and Leaves the Town: The Gates were Built with the Idea That Tourists, after being Greeted at So Many Cities with Traffic Warnings and Regulations, would Favorably Remember This Town This Artificial Fountain, In Commemoration of the Discovery of Gold in California, This Building Said to Be the Highest in has been Erected over the Dilapidated Remains of the Old Blacksmith the World, and Known as Shop That Belonged to James W. Marshall, the Discoverer. Seven Miles the Andrews Geyser, is Lo- Distant Is Coloma, Where the First Gold Strike was Made cated on the Asheville Di- vision of the Southern Rail- way, near Mount Mitchell, North Carolina. The Water, from a Mountain Spring, ANDOT Spurts 110 Feet into the This Sign, with Its Object Clear Mountain Air Plainly Legible in the Pic- PURE SPARKLING WATER — OURFORTIFICATIO: PROMOTES ture, Is 18 Feet Square. The ae, +. a aoe a PROGRESS. PROSPERITY 4x» GOOD HEALTH orr is ollowing wapottrs Mone : . t the Sign’s Advice, and is Not Serre ee ae ee Going by “Dry.” At Night the Sign is Illuminated x Two Electric Lights

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AND ENJOYMENT OF VISITORS AND RESIDENTS Rounded Block of Concrete, Built against an Un- usually High Curb, That Makes It Easy for —— Pedestrians to Mount to the Sidewalk, and at the a Same Time Forms No Obstacle to Wheeled Traf- The Solid Concrete Base on Which This Sign is fic: It Is of Such Shape That Automobiles can Mounted will be Avoided by Motorists Who Have Pass over It without a Jolt Any Respect for Their Cars. It is Used in the “a Streets of Springfield, Illinois, to Preserve a a Safety Zone for Passengers Boarding and Alighting from Street Cars. Above the Sign Isa Red Lantern — ee j ( inside the Concrete Curb, ho 1 cated Right on the Sands, at the Beach of Santa Barbara, California, Bathers can Stand under an Ordinary Overhead Shower Sprinkler, Supplied with Fresh Water, and Wash Off the Sand and Ocean Brine, without Having to Wait Till They Get Back to Their Dressing Rooms, as Is Usual at Most Beaches. This = a Very Popular Convenience In Connection with a Fire- Prevention Campaign in In- dianapolis, Indiana, This Large Dial, at a Busy Cor- ner, Has a Red Hand That Shows the Number of Fires in the City during One Month, and a Black Hand That Shows the Number during the Same Month of the Previous Year

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4356 POPULAR ELECTRIC FOOD MIXER BUILT FOR MEDIUM-SIZED KITCHENS A new electric food mixer is designed es- pecially for the kitchens of hotels, restau- rants, clubs, bakeries, and ice-cream par- lors. It hasa 24-qt. mixing bowl, support- ed by a stand which occu- pies a 24 by 23-in. floor space. It is al- so furnished without the stand. A food chopper is supplied if de- sired. The whole ma- chine is 55 in. high. The mixer is oper- ated by a \,-hp. heavy- duty moto, mounted at the top of the and a gear shift provides two It is finished in light-gray enamel. frame, speeds. FUEL IN GASOLINE ENGINES COMPLETELY ATOMIZED Improvement of the carburetion of the charge in the internal-combustion engine has been effected by the application of heat to promote vaporization, or of vio- lent agitation to increase atomization. In a new device, that is now on the market, agitation of the mixture is caused by plac- ing in the inlet manifold, at the inlet port of the cylinder, a short tube with a Ven- turi orifice, which has the property, as is well known, of greatly increasing the ve- Atomization of Charge in Gasoline Engines Increased by Tube with Venturi Orifice in Inlet Port of Cylinder, and Jets for Atomizing Liquid Deposits below Tube IECHANICS locity of the flow of a fluid from the outlet side of the Venturi throat, and of causing suction on the inlet side. Below the tube is a small sump, into which any unatom- ized units of the mixture drop by gravity, and the suction has the effect of lifting these units through a jet in the tube which atomizes them when they reach the main body of the inflowing charge. Thus no liquid fuel reaches the inside of the cylin- der, with resulting advantages that every motorist will appreciate. NEW CONVENIENCES FOR INVALID’S WHEEL CHAIR Wheel chairs are now being made with accessories, for the convenience of the in- valids who must depend upon them. One of these is a luggage carrier which provides a place for books, maga- zines, and wraps. Cane and crutch carriers are attached to the back of the chair, where they are out of the way but always within easy reach. Brakes, similar to those used on baby car riages, are also provided. These hold the chair steady when the patient does not wish to move about. METAL UKULELE PEG FITS ALL TYPES Any size or shape of ukulele shaft can be fitted with a universal metal peg lately patented by a New York inventor. The peg, which has a celluloid but- ton, will hold a string at a heavy tension without slipping, because of its construction, and may be man- ufactured to sell at a very low price, according to the inventor. Be- cause of its many good features, it is thought that the in- vention will prove popular among those who play this instrument.

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POPULAR MECHANICS Left: Exterior of Automatic Banking Machine. Above: Interior Stamp- Delivery Mechanism. Right: Front Re- moved, Showing the Money Containers THRIFT EFFECTUALLY TAUGHT BY NEW SAVINGS SYSTEM Thrift is being effectually taught to school children by the installation of au- tomatic banking machines, which are lo- cated in the school buildings. The ma- chines are operated after the fashion of the familiar candy or gum-vending ap- pliances, in so far as pertains to inserting money. The child may put in a cent, nickel, dime, or quarter, and receives in return a stamp marked with the respec- tive amount of his insertion. These stamps are pasted in a previously dis- tributed folder, and when the amount on the stamps totals one dollar, the child takes the folder to a savings bank, and opens an account. Although primarily designed for the efficient handling of school savings, this system has been in- stalled in numerous factories, business houses, and public buildings. PEN WITH AN INK RESERVOIR AVOIDS CONSTANT REDIPPING Writing pens that will take up, when dipped in the ink, a much larger supply than the common pen point are the sim- plest form. of fountain pen. One that is now on the market con- sists of a perforated piece of rubber tub- ing that is inserted into the hollow shank of the pen point, and that fills up with ink, holding, it is claimed, enough to write 1,000 words without redipping. The ink is fed gradually through holes in the rub- ber tube to the writing point of the pen, and does not blot the paper. SIMPLIFIED AIR PORT HAS NO TUMBLE BOLTS Many of the troubles, well known to seafarers, of the ordinary air port are avoided in a patented port that is being manufactured in New York. Instead of the dogs for tumble bolts, as in the con- ventional port, the glass frame has four fixed curved lugs on its outer circumfer- ence. Snugly fitted to the inside of the fixed frame of the port is a ring with four Left: Air Port, without Deadlight, Completely Open. Center: Air Port with Deadlight Closed. Right: Air Port Closed and Locked, with Deadlight Up similar lugs on its outer circumference, which engage the lugs on the glass frame when the port is closed. In the fixed frame is a crank handle, which, when turned, revolves the ring until the lugs become disengaged, and then by means of spiral gearing on the hinge of the glass frame opens the light, the operation being so timed that as it opens, the light clears the crank handle. By reversing the handle, the light is closed and latched. A deadlight, similar to those in common use, may be attached to this port. This re- quires the conventional swivel closing bolt.

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SOME NOVEL AND LITTLE-KNOWN ACCESSORIES

Left: This Salt or / ; With This Shell- Pepper Shaker fish Scraper, the Opens When the - "| Meat can be Re- Top is Pressed. Be- moved from the low: By Merely Inside of Shells Pressing the Sides, ) and Claws the Top is Again Closed

A Dustpan Which is Held in Position by the Foot, So That the Housewife can Use Both Hends in Taking Up Sweepings, without Stooping

7

wr Counterbalanced Electric Lamp Which can be Hung Quickly over the Back of a Chair, Bed, or Dressing : Table: The Fixture Has a Ordinary Cord Attachment

An Electric Clothes Wringer Having Large Soft- Rubber Rolls, Which Wring Drier Than Other Types, do Not Break Buttons, Nor Injure This Fruit-Jar Sealer and Opener, Fingers, and Are Self- Made of Unbreakable Malleable Cleansing Iron and Steel Wire, Opens and ~ Tightens Any Jar, and Smooths Out the Edges of the Covers

<e—eomeape -ooep romaine Sant —gS SECT CG AN RE a me 3. Di

Top: The Combined Crib and Wardrobe Showing the Drawers Built under the Mat- tress. Right: One of the Drawers Pulled Out for Use as a Table. One Side of the Crib can Also be Lowered a TW Ore

438 Anyone wishing further information on devices described in the editorial pages can

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INTENDED FOR THE AND ITS MEMBERS This Brush, Made for Cleaning the Drain Pipe of Refrigerators, Has a Long Flexible Wire Handle, and Its Use will Prevent the Pipe from Clogging and Overflowing A Combined Electric Toaster and Heater, Making Possible the Use of These Two Appliances at the Cost of Only One A Paper Weight, Which Also Serves as 2 Writing-Desk Set, Has Compartments in Which can be Placed Pens, Ink, Stamps, and Sealing Wax. There Is Also a Tube Support Which Prolongs Space for the Owner’s Monogram the Life of the Tubing by Pre- venting It from becoming Kinked and Consequently Broken, as Is Often the Case When a Tube is Hung from a Nail aa A Jelly Tumbler —s : , a mm, Which is Sealed by Dripless Broiler Which Re- imply Pressing the tains All the Juice of the ~~ + ; : a ot the Gover, Food and Thus Prevents the — . m- and Opened by Stove from being Soiled and — Pressing the Center Causing Smoke Left: Folding Table Ready to be Used as Breakfast Table. Right: The Table with the Sides Down and Ironing Leaf in Position for Use, Below: The Table Knocked Down and in Readiness for Moving obtain it by addressing Bureau of Information, Popular Mechanics Magazine, Chicago.

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440 SIMPLE PRINTING TELEGRAPH COVERS NEW FIELD OF USE A simplified printing telegraph suit- able for inter-department communication in large plants, as well as main-line traf- Combined Receiving and Sending Unit: The Receiv- ing Tape Protrudes from the Left Side. A Full- Size Section of Tape is Shown Above fic, is now on the market. The simplicity is obtained by printing on a tape in place of a sheet, so that much complicated mechanism is done away with. A trans- mitter, with a keyboard similar to that of a typewriter, is mounted with a printer to form a single unit. This unit is operated on either direct or alternating current, of 110 volts, by a “%o-hp. motor. The keys control a camshaft, which revolves, open- ing and closing the line. The maximum speed is 45 words a minute, a safety de- vice preventing too rapid operation. NEW TOOTHBRUSH STERILIZER KEEPS BRUSH SANITARY Because of the opinion, generally held by doctors and dentists, that an unsterile toothbrush may be a greater hindrance than benefit to health, the claims made for a new toothbrush sterilizer are in- teresting and important. It is stated the Pad Container izing Solution Toothbrush Case Open, Showin and a Bottle of the St POPULAR MECHANICS that by using this simple container the brush is kept perfectly sterile. It con- sists of a two-piece case, of aluminum, just large enough to hold a toothbrush. In one half a small metal box, containing a pad, is held on the inside by ridges in the case. At regular intervals the pad is moistened with a special sterilizing solu- tion, and the brush is kept in the case at all times when not in use. NEW CARDS MAKE BRIDGE GAME OF SKILL ONLY, NOT LUCK Cards for playing bridge, in any of its forms, have been produced which re- move all of the element of luck from the game, and make it purely a game of skill. The backs of the cards are marked with numbers and indicators and the cards are dealt according to the indicators, instead of in the usual way, by rotation. The re- sult is that four absolutely equal combi- nations of cards are obtained by the four players. There are 12 sets of indicators on each pack of cards, making possible 12 entirely different hands or sets of com- binations. After the cards have been dealt, the game is played in any of the or- dinary ways. NEW APPLIANCES MADE TO AID BATTERY MEN Two new tools for the use of the bat- tery man have lately been produced and placed on the market. One is a small hoe-shaped tool for the disagreeable task of removing the compound from the bot- tom of old battery cases. The other is a knife-shaped blade with teeth on one Top: Scraper for Removing Old-Battery Compound. Below: Knife for Separating Battery Elements side, to be used in removing the separa- tors between the elements of the _ bat- teries. @ As a means of combating counterfeits of her creations hereafter, each garment of a celebrated French modiste will bear a special serial number, a notice of license an autographic signature, and the thumb print of the designer.

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POPULAR MECHANICS 441 THREE-DIMENSION WEATHER MAPS MADE FOR AIRMEN The Maps are Photo- graphed from Two Different Angles, and the Two Photographs are Mounted Side by Side Three - dimen- sion maps are being made by fame B35 3% ae Upper-Air Stations are Marked by Posts and Arrows, Tadicat- ing the Wind Direc- tion and Velocity at Different Levels post, supporting a series of ar- rows, is set up. the United States Weather Sureau as a re- sult of the de- velopment of flying. It was found neces- sary to chart wind directions at different levels for the airmen. At first, separate maps for each level were made, but these proved awkward. Now an _ ordinary weather map is drawn and at the location of each upper-air station a little metal When the Two Maps, Shown Above, are Viewed through a Stereoscope, They Blend and Appear, as Seen Here, with the Posts and Arrows in Strong Relief Each arrow is a little shorter than the one be- low. They are set to indicate the wind direction at the levels they represent. Numbers on the arrowheads show the wind velocity. The map is photographed from two angles, and when the two pictures are seen through a stereoscope, they blend, bring- ing the posts and arrows into strong relief. INGENIOUS SYSTEM SOLVES DOUBLE-CARFARE PROBLEM Street-car passengers between St. Paul and Minneapolis must pay two full fares. Formerly the conductor collected in the car and repeated the collection after pass- ing Snelling Avenue, going east, and Bed- ford Street, going west. Snelling Avenue is east of Bedford Street and the space between the two forms a neutral zone from which a person may ride in either direction for one fare. This year the company adopted “pay-as-you-enter” cars with rear entrance and front and rear exit. A system of collection had to be worked out so that the conductor would not have to leave his money box to col- lect. When a passenger boards the car before passing the neutral zone, he pays at the rear on entering and can get off at either end before passing the neutral zone. After passing that zone all pas- sengers must get off at the rear and pay WEST PAY AS YOU LEAVE Ld HSER ————— —4 i ny ae eR Ressssss C MINNEAPOLIS DAY AS YOU ENTER AN BEDFORD STREET — RAI NEUTRAL EAST Pay AS YOu ENTER - ZONE Diagram Showing How the Interurban Street Railway, between Minneapolis and St. aul, Handles the Collec- tion of Double Fares on a. to Cars, and the Neutral Zone in Which nly One Fare is Required

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442 POPULAR on leaving. Passengers boarding the car in the neutral zone are given blue identifi- cation slips which they give the conductor on getting off, in place of the second fare, which they are not required to pay. ELECTRIC HAND DRIER BUILT INTO WALL TO SAVE SPACE Space, so valuable in modern city apartments and buildings, is now being economized by recessing the ordinary electric hand drier into the wall of the bathroom. The movable blower is set in a plate at the correct height, and be- low it, the op- erating pedal is set in a second plate, just above the floor. This eliminates the awkward pedestal which was formerly used.

DISPENSING MACHINE DELIVERS WELL-MIXED PEANUT BUTTER Properly mixed peanut butter can be dispensed in small quantities from 60 or 80-lb. cans by means of a new dispensing ma- chine. It is placed on top of an open can, clamped on with three rods, and the whole then inverted. Two paddles, re- volved by the dis- pensing handle, extend into the butter. The han- dle is turned a few times before opening the dis- pensing valve, to mix the light and heavy oils and butter thoroughly. Each time it is turned to dispense butter it again revolves the mixing paddles.

MECHANICS CHINESE GREATLY MYSTIFIED BY WIRELESS TELEPHONE Mystification of the usually placid Chi nese was accomplished by a noted Amer- ican professor, who has been lecturing on, and demonstrating, the latest develop- ments of electricity throughout the Orient during the past six months. Placing a wireless-telephone station on a _wheel- barrow, the professor had the outfit trundled through the streets, stopping every little while to converse with asso- ciates, who had set up similar stations in their living quarters. The carrying on of conversations from the interiors of thick stone walls, and receiving responses from several different directions at once, par- ticularly impressed the Orientals, and added to their bewilderment. NEW SAFETY RELIEF VALVE OF IMPROVED DESIGN A plumbing specialty in the form of a safety relief valve of improved design, is now on the market. Integral with the a valve body is the valve seat, which is made small in order to prevent it from damaging the valve disk when under pres- sure. On top of the body is a re- movable cap, upon the outside of which is bolted a C-shaped spring that never comes in contact with the water, an un- desirable condition that is common in other relief valves. Above the bolted end of this spring, a small adjusting wheel is threaded on the plunger that is connected with the valve disk. When this is set for any desired pressure, it is retained in its position by means of a loose lead-tipped wire on the upper end of the spring. <A side outlet on the body provides means for taking care of the drip by piping it to any open- plumbing fixture. @ Those wishing further information on anything described in the editorial pages can obtain it by addressing Bureau of Information, Popular Mechanics Maga- zine, Chicago.

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POPULAR CHARACTERISTIC SOFT X-RAYS FROM ARCS IN GAS VAPORS The outstanding characteristic of the X-rays which were first discovered was that they would pass through solid bodies which were opaque to ordinary light. Experiments have recently been con- ducted in which soft X-rays from arcs in gas vapors have been produced inside vacuum tubes. All known substances, including ordinary air, are opaque to these soft X-rays, which can only be detected by their effect on objects inside the vacuum tube. These soft X-rays have wave lengths greater than those previ- ously known. The shortest wave lengths of light, at the violet end of the visible spectrum, are much longer than the long- est previously known X-rays, and meas- urements of the wave lengths of these soft X-rays have shown that they par- tially close the gap between the ultra- violet radiations and the ordinary X-rays. SLOT IN TABLE FACILITATES WORK ON SEWING MACHINE Sewing-machine tables are now being provided with an L-shaped slot, 3 in. wide, that enables an operator to feed material more conveniently to the needle. A piece of material requiring a continuous band Slot in Sewing-Machine Table through Which Mate- rial Hangs So That It can be Fed without Diffi- culty under the Presser Foot at the Needle can be sewn by letting it hang through the slot while it is fed under the presser foot at the needle. @An engine on the Canadian Pacific Railway recently demonstrated its haul- ing possibilities by pulling 112 cars, in- cluding the usual tender, and caboose. The train was nine-tenths of a mile long, and was loaded with 165,000 bu. of grain. MECHANICS 443 PERFECT LIGHT BUT NO DAZZLE FROM ENGLISH AUTO LAMP An automobile lamp, being marketed in England, is said to control the light rays in such a way that while an approaching The Nondazzle Auto Lamp: The Diagram Above Shows Arrangement of Diaphragm and Lenses, and the Outline of the Stream of Projected Light pedestrian suffers no blinding effect, at a distance less than 200 ft., yet it lights the road perfectly for that distance. The body of this lamp is a tapered tube, 10 in. long, with two D-shaped lenses in the front and a horizontal diaphragm dividing its whole length. The two streams of light mingle, giving a single horizontal and downward stream. The width of the stream, at any point, is about one-half the distance of the point from the lamp, but the construction can be varied to give a narrower and more intense or wider and less intense stream. BURGLAR-PROOF WINDOW CATCH LOCKS SASH AT ANY POINT Windows are made completely burglar- proof by a new catch, which the makers claim cannot be jimmied, and will lock the window in any position. From the in- side, the win- dow may be opened to any desired height, but cannot be mo, opened any farther from the outside. The catch is set flush in the frame, so that it does not catch and tear the curtains. @ Write our Bureau of Information, if you wish to know who makes or sells any article described in this magazine. Send no postage; the service is free.

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CHILDREN’S PICTURE-STORY DEPARTMENT A Group of Native Girls from India Arriving in London, England: These Girls were Given the Trip as Guests of the Salvation Army, as a Means of Furthering and Broadening Their Education by First-Hand Contact with the Western World. Dressed All Alike, in Their “Little Red Riding Hood’’ Cloaks, the Youthful Visitors from the Far East Attracted Much Attention Wherever They Appeared and, Needless to Say, They were Delighted with the Many Strange Sights, Experiences and Entertainments Encoun- tered on Their Trip, Which had Taken Them So Far from Home and Familiar Surroundings ee —— — | | $§mall Visitors at the New York Zodlog- ical Gardens can Now See All the Sights without Becoming Tired. Their Mothers may Hire One of These “Prams,” Fur- nished by the Zoo, and Also an Attend- ant to Push It, for a Small Price COPYRIGHT, KEYSTONE View CO ee ars >~ ST 6 ee is a “4 3 Z 4 * ‘ (a J on ; 3 eit oS a “Jimmie” Uses the Phonograph as a Merry-Go- Round. He Presses the Starting Lever and umps on for a Ride. This Is One of Many Wie s of This Pet Squirrel, Belonging to Miss Manilla Martan, of New York City COPYRIGHT, KADEL & HERBERT

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MODERN ACTIVITIES AND INTERESTS A White-Enameled Table and Chairs, for the Children, are Shown at the Left. The Table Top Is of White Porcelain and may be Washed Easily if Food is Spilled on It hcl The Shooting Gallery, at the Right, Has a Ball for a Target. Air Pressure, Obtained by Pressing the Lever, Supports the Ball, or a Model Operated by Current from an Electric- Light Socket may be Had Peon ™ Circus Parade Carved from Soap, for a Window Display: The Material Re- sembles Old Ivory; the Coloring Is Ink, Applied with a Pen and Brush The Original Horseless Car- riage, Exhibited at the Chi- cago World’s Fair in 1893, was Run by Steam. It is Now Owned by Colonel Wm. N. Selig, of Los Angeles. The Crew of the Machine, as Seen in the Picture, Are ‘‘Mary”’ and Mike,” Two Chimpanzees of the Moving- Picture Colony, Which have Entertained housands of People by Their Almost Hu- man Antics in the Movies

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446 POPULAR CARBON-PROOF SPARK PLUG MANUFACTURED IN FRANCE A carbon-proof spark plug, similar to any ordinary plug, except that, in place of a side electrode at the sparking point, it COPPER ~ ASBESTOS GASKET Below: Carbon-Proof Spark Plug with the End Milled Out to Show Disk in Its Circular Slot. Above: Sec- tional View Notated Fully to Explain the Construction has a loose movable metal disk that is re- tained in a circular slot made by spin- ning over the end of the plug, has been patented, and is now being sold in France. In the center of the disk is a hole, which surrounds the end of the central electrode, and the space between this and the inner circumference of the hole forms the spark gap. With this construction it is impossible for carbon or oil to pass the metal disk and reach the porcelain inside the plug, one of the commonest causes of short-circuiting. As the disk is constantly vibrating and rotating in its slot, it is unlikely that oil or carbon will lodge in the spark gap. SOD-CUTTING MACHINE AIDS IN PRESERVATION OF LAWN For the laying of pipe, or similar pur- poses, where the turf must be cut, a ma- chine is available that removes a strip of sod quickly, and Be Sod Cutter with Sharp-Flanged Front Roller, Lifting Tool, and Rear Roller with Cutting Knives Affixed MECHANICS without damage to it. The appliance has two handles like a plow, two heavy roll- ers, and a tool for lifting the cut turf. The front roller has sharp flanges on either side which cut through the sod, and the lifting tool is adjusted so as to raise the turf as the roller cuts it into strips. The rear roller has knifelike pro- jections on it to cut the sod in regular lengths, ‘after which it is piled up and relaid when the work is completed. SHELLS HUNG IN CHURCH TOWER REPLACE CONFISCATED BELLS Church bells throughout Germany were confiscated during the war to be melted up and used in the manufacture of munitions. One of the most novel and ingenious substitutes which has been re- ported was used in the town of Marhorst. Two large shells were suspended in the church tower and a pendulum swung be- tween them. When the pendulum struck the shells it produced a pleasing tone with surprising carrying power. SIMPLE MACHINE DISTRIBUTES ARTICLES INTO COMPARTMENTS For distributing articles, such as fruit, into several compartments, a newly in- vented machine is quite simple. The end Simple Distributing Machine Which Separates Articles, from a General Hopper, into Several Compartments of a chute, down which the articles pzss from a hopper, is provided with upward curving teeth. A revolving cylinder be- low has rows of teeth, which pass be- tween those on the chute, and pick up the articles. From the teeth they fall into an opening in the cylinder and a small chute carries them to one of the compartments below. @Our Bureau of Information is for your benefit. Use it as often as you please.

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Information as to where to obtain any specified materials or parts for makin the following pages may be had from our Bureau of Information.—KEditor. objects described in on request, Corners for Log Cabins By A. NEUMAN N building log cabins, the parts that cause the most trouble are the corners, where the logs cross each other at right angles. To get the best and most attrac- tive effect, and to retain the “pioneer” look, the logs should project beyond the corners, but, unless properly done, the effect will not be pleasing. The pictures show how accurately and neatly the logs can be joined at the corners. To make although, if necessary, it can be done. The logs should be cut about 6 ft. longer than the inside dimensions of the build- ing, and good straight ones should be selected; they should also hold their size well, that is, they should not taper very much. The notches are marked with a com- pass with an indelible-lead point, if green timber is used, as an ordinary pencil or

* TIMBER DOG % ROUND IRON

12

COMPASS WITH INDELIBLE POINT —

If a Neat and Finished Job is Desired in a my Building, Particular Pains must be Taken to Fit the Logs otches Accurately at the Corners. By Marking the Corner Is the Result. this type of corner it is necessary to have made at a blacksmith shop a gouge adz along the lines of the one shown. The cutting edge is ground with an inside bevel and sharpened with a slip stone. The hammer head is to give it the right “heft” and balance, and is useful to drive the timber dogs into the logs to hold the latter while they are being notched. Two of these timber dogs are needed, and they are made and used as shown in the draw- ing. Peeled logs are best to use, as it is quite difficult to get a distinct pencil mark o1 the bark of a rough log, ccording to the Method Described, a Very Neat The Drawings Show the Tools Used and the Method of Marking Off the Logs ead will not make a good mark on the surface of freshly peeled logs. Two logs are dogged together at right angles, as shown; the compass is set to a radius of a little less than half the diameter of the log to be cut, then, with the steel point against the lower log and the pencil point against the upper one, it is drawn over the surface of the logs as shown, mark- ing, on the upper log, an accurate repre- sentation of the contour of the lower one. A similar mark is made in the same manner on the opposite side of the upper log, which is then rolled over, dogged 44)

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448 again, and the notch cut. It should be noted that the notches are cut in only one side of each log—the underside. As the logs taper somewhat, the diame- ter of the notch at the small end must be a trifle smaller than the diameter of the notch at the larger end. If the joints do not fit exactly when first cut, the compass should be set with its points 4% to %% in. apart, new marks made, and the notches ‘cut down to these marks. If the work has been carefully done, extra fitting is usually unnecessary; after the first few experiments with the method, neat and accurately fitting notches can be cut, and, where the work is exceptionally well done, it is hard to tell which log is cut. About an inch of space is left between the logs, and this space is “stuccoed” ac- POPULAR MECHANICS cording to the methods commonly used. Straight logs should be selected for build- ing purposes, but if there should be a slight bend or bow in some of them, they should be placed in the building with the bow up, so that, in time, they will sag and straighten out. The logs settle a great deal more than is generally thought after being put in place, and it is advisable to allow the building to settle for two or three months before furring in the doors and windows, or trying to stucco the chinks between the logs. If the building is allowed to settle for a while, nails driven close up into the cracks, about 2 or 3 in. apart, and the chinks then filled, the stucco will stay tight for years, as the heads of the nails will be imbedded in it and hold it tightly. Wrench for Cylinder-Head Bolts It is difficult to place a straight open- end wrench on the cylinder-head bolts of certain makes of automobile engines, as the nuts are set below the surface in such a manner that a good grip cannot be taken. In such cases a wrench of the type shown in the drawing can be used to consider- able advan- tage. It is \ {fo = only necessary COUNTERBORE ade | * to bend over ‘ ¥ the open end of the wrench, so that the jaws will fit into the counter- bore or depression in the casting. (CYLINDER HEAD \ - BENT ———__ Cleaning Silver Cathodes Silver cathodes for use in the electro- deposition of copper are cleaned by plac- ing them in contact with pure tinfoil in a boiling 10-per-cent solution of sodium hydroxide until bright. They are then washed successively with dilute hydro- chloric acid, dilute ammonia, and dis- tilled water, rinsed with alcohol, burning off any adhering alcohol by igniting it. The electrolysis is carried out as usual, except that the electrode is not immersed in the solution until the current has been switched on. To remove the copper de- posit, after the final weighing, the cathode is placed in a wide-mouthed stoppered bottle, filled with a 10-per-cent solution of trichloroacetic acid in aqueous ammo- nia (.90 specific gravity), to which an equal volume of water has been added. The copper is removed in about minutes and the silver electrode is not attacked. Chloroform or carbon tetra- chloride may be substituted for trichloro- acetic acid, but in this case the ammonia solution should be made from one part ammonia (.90 specific gravity), and one part alcohol. The reaction is slower, and care must be taken that no sulphur com- pounds are present in the carbon tetra- chloride that is used. ten Driving Long, Slender Pins A very efficient tool for driving long, slender pins that have a tendency to bend when being driven, because their length is so much out of proportion to their diameter, and also because they are not al- ways set squarely, is shown in the drawing. The part that holds the pin is made from 14- in. steel, drilled through to accom- modate the pias, and a slot is cut thropgh to within LHoue %e6 in. of the end. The punch, or driver, is a piece of %e-in. flat steel, 1% in. wide, held by means of a pin in the sliding punch holder, which is drilled out, 4% in. in diameter, to within a short distance of the top. Care should be taken in mak- ing this tool to see that the flat piece fits

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POPULAR MECHANICS the hole in the punch holder neatly, as this supports the driver lengthwise. When the two parts are assembled, the flat punch should slide nicely in the slot of the pin holder. When driving the pins, they are first placed in the hole and the driver slipped over them; then, taps on the top of the punch holder will drive them home to within %¢ in., a final tap being sufficient to bring the pin flush with the face of the work. It will be seen that the pin is supported at all times by the holder, and that the punch holder pilots the punch down centrally, thus overcoming the two main difficulties mentioned. — Harry Moore, Montreal, Can. Shop Uses for Old Razor Blades Old safety-razor blades can be put to good use on the bench by soldering on sheet - metal handles, and then using the blade as a guard in filing the corners of dies and cast- ings. Even a safe - edge file will some- times cut up a finished metal surface badly, and the blade will form a good protection when any file, even a three- cornered one, is used. Instead of a single handle, especially on repetition work, a metal clip can be soldered to each side of a blade to hold it up against the work, so that both hands will be free to use the file. Sticker Identifies Rush Orders Small gummed-paper stickers, such as can be bought at any stationery store, are used on the order cards of a large concern to indicate rush orders. A red seal is stuck in the upper left-hand corner of the card, and everyone who gets the shop ticket knows instantly that the or- der is to be handled with speed. A vari- ation of the same idea makes use of a blue seal, which enjoins everyone to take particular pains in filling the order, or in working to dimensions, Heating Water with Steam Heating cold water by steam is ac- complished in various ways, the most common method being to insert the end of a steam 5° pipe into a 3 PIPE TO SINK, tank of water and turn on the steam. This method, besides being wasteful of steam, pro- duces dis- agreeable noises. The drawingshows a simple fitting in which the steam is mixed . » with the cold water, so that "O} this is heated and passes on to an outlet without any fuss. The water and steam-supply pipes are controlled by separate valves, making it possible to regulate the temperature of the heated water very closely. — Ear! Stevens, Niagara Falls, N. Y. __ STEAM SUPPLY Safety Container for Gauge Glasses In dismantling large ammonia compres- sors for shipment, most of the small parts are easily disposed of by packing them in a box fastened to the skids. There is one piece, however, that does not mix well with the rest, no mat- ter how carefully it is wrapped in bur- lap or corrugated cardboard, as it in- variably works its way under a heavier piece and is crushed. This is the gauge glass. The difficulty of transporting such glasses, and for that matter all kinds of glass tubing in short lengths, can be solved by using a block of wood in which a hole, 1 in. longer and about ‘%2 in. larger than the glass, is drilled. The tube is inserted in the hole, and a small block, fastened over the open ing with four brads, makes it possible for the gauge glass to ride safely along with valves, oil cups, and other small parts

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450 POPULAR Automatic Stop for Tumbling Barrel When tumbling some small castings, to remove the sand and burrs, trouble was experienced when the pieces were tumbled PULLEY CORD TO COUNTERSHAFT— TUMBLER ~ _ STAR / WHEEL Nae] An Automatic Stop for a Tumbling Machine -Prevents Injury to Castings by being Tumbled Too Long too long, the result being that the cor- mers were worn round. The trouble occurred mainly because the operator for- got to stop the tumbler when the work was done. The result of this experience was that the automatic stop illustrated was devised; this required a new bearing at one end of the machine. The cast-iron bearing supports the tumbler shaft and the threaded stem of the star wheel, a hole being first drilled for the stem, then the hole slotted out on top, and a ma- chine-steel cap fitted. The bearing for the star-wheel stem is tapped to fit the thread on the stem when the cap is in place, as shown. Afterward the thread in the bearing is removed so that the only part having a thread is the movable cap, which is held in place by a pin. A key is driven into the tumbler shaft to operate the star wheel. The end of the star-wheel bearing nearest the tumbler has a weight hooked over it to operate the counter- shaft, which is not shown. When the tumbler is ready to start, the attendant takes out the pin, lifts the cap and slides the star wheel out to the posi- tion shown; then the cap is secured in place again, the countershaft cord pulled to start the machine, and the weight hooked over the bearing; the tumbler can MECHANICS then be left to stop itself. As the threaded stem of the star wheel is 3 in. long and makes only one-fifth turn for each revo- lution of the tumbler, and the stem has a 20-pitch thread, it takes 300 revolutions of the tumbler before the star wheel is fed through enough to push the weight off its bearing, and stop the machine.— S. A. McDonald, Brooklyn, N. Y. Stencils Made from Old Films I find that the best material from which to make air-brush stencils is old photo- graphic film, such as can be obtained from any professional negative finisher or photographer, many of whom have dis- continued the use of glass plates. Such celluloid masks are much more durable than those of paper, and the alcohol in the colors cannot strike through and stain the work underneath. The designs may be drawn on the rough surface of the stencil directly, then cut out with an old razor blade —R. E. Deering, Clem- ents, Kan. Marking Bolt Circles When turning a cover, flange, gland, or other work that will afterward require a circle of bolt holes drilled in it, it is the usual practice to mark or “strike” the bolt circle, that is, cut a fine tool mark in the face of the work at the required diam- eter, while the work is held in the chuck or faceplate. This is generally accom- plished with a V-shaped tool, held in the toolholder, and the proper radius is ob- tained by ad- justing the tool to a scale held against the lathe cen- ter. The draw- ing shows a special tool for this work, which is sim- ple to make and easily ad- justed to the correct radius. The body is turned on the shank to fit into the tail- stock spindle, the front end having a 3g-in. hole drilled through it at right angles to its center, and a small hole at the center, tapped for a setscrew. A piece of %-in. cold-rolled steel, of suitable —— SETSCREW — MARKING TOOL “SLIDING SCALE PP» AND TOOLHOLDER ERECT EE EL CCF TAILSTOCK V - GROOVE ~ SETSCREW

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POPULAR MECHANICS length, is centered and placed in the lathe, where a 16-pitch thread is “scratched” on it. The thread is not actually cut, but a fine helical line is made on the rod, which is then grooved on one side to fit the point of the setscrew, and fitted at one end with the marking tool and setscrew. The diameter of the body of the tool should be large enough to permit a flat to be filed on one side, the flat being filed at an angle corresponding with the angle of the thread, and so that when the mark- ing tool is snugly against the flat, the distance from the center of the tool to the center of the body is exactly one inch. When setting the tool, pull out the bar until the measurement of half the diam- eter of the required circle is obtained, and then tighten the screw. The tool is held in a vertical position so as to clear the toolholder of the lathe, and is fed in by means of the tailstock until a fine line is marked on the work. Face Milling with Side Mills A good deal of quick face milling can be done with the ordinary face and side- milling cutter when held in the simple holder illustrated. This is turned, on the shank, to fit the spindle, and on the front to a snug fit in the bore of the cutter. A shoulder, to take the end thrust of the cut, is left on the holder. The center of the holder next drilled. tapped, and counterbored for the spe- cial screw in- dicated. This is an ordinary filister-head screw with the head turned to a slight taper. At right angles to this hole is another, drilled to a diameter the same as the width of the keyway in the cutter. A piece of drill rod is inserted in this hole, and the tool is ready for use. It will be seen that when the screw is tightened, the drill-rod pin will be forced out against the cutter and act as a driv- ing key. With a cutter held as shown, and close to the spindle of the machine, face-milling operations can be success- fully accomplished. /DRILL ROD aj _TAPER-HEAD SCREW } 15 t Rack for Storing Sheet Glass So-called “country” hardware and paint stores, that carry an extensive assortment of sizes in sheet window glass, realize > '™ ~ oil A Rack for the Storage and Display of Flat Window Glass That is Made Up of the Boxes in Which the Stock is Received how difficult it is to arrange the different- sized boxes to the best advantage and with the least possibility of loss by break- age. The drawing shows an idea that has been worked out by a jobber who is rec- ommending it for the use of his trade. The rack is built up of empty glass boxes, the glass, as received, being removed from its case and placed in the rack.—Arthur Hartley, Fargo, N. D. Crankshaft-Turning Tool When an automobile motor is being overhauled and the crankshaft or con- necting-rod bearings are being fitted, dif- ficulty is usually experienced in turning the crankshaft, as both the flywheel and starting crank are removed from the engine. Even with these in place, con- siderable effort is required to turn the shaft in the tightened bearings. A sim- ple tool for turning the shaft can be made from the V-shaped radius rod of a light automobile. The ends of the radius rod are brought within a few inches of each other, the ends ground down to fit into the bolt holes in the flywheel flange, and then bent over. Apart from its sim- plicity, this tool affords the proper lever- age and can be set into any pair of the flange bolt holes.

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POPULAR Correct Design of Movement for Intermittent Motion Most machine designers and draftsmen have occasion to make use of cams and Geneva movements in their work, and these certainly form two of the principal elements in the study of machine design. Results are obtained by using them which would otherwise be impossible, and upon whether they are correctly or incorrectly used depends the success of the machine in a great many cases. High-speed pro- duction is a great factor in present-day machine oper- ation, and it is surprising to find the number of de- signs which fail to meet this condition, although it should be one of the first things to con- sider. Har- monic cams, being capable of high speed, should be used whenever possible. When a uniform or constant motion is required for the cam roller, the entire movement cannot, of course, be harmonic, but an effort should be made gradually to accelerate the roller at the start and gradually retard it at the end of its movement; in most cases this can be done, though often neglected. In the present example a machine was to be redesigned. The highest possible speed was 15 cycles per minute; it would have broken down at a higher speed, and to make it a commercial success more speed was absolutely necessary. Its vari- ous moving elements consisted mainly of abrupt-movement cams and Geneva move- ments. A close examination revealed the fact that the design of these parts was not based upon the principle of gradual acceleration and retardation. The cams and Geneva parts were redesigned, and in so doing it was found that most of them could be given true harmonic forms, and, in .consequence, the machine was operated up to a speed of 90 cycles per minute, without undue vibration, and without exceeding safe stresses. One of the several sources of trouble in the original design was the Geneva action pate SLOT DRUM 4 Lew DRIVING saianed SLOTTED RING — Fis.! INTERNAL GEAR 7 DRUM : SOR £ PINION ~ 4S ROLLER —~) DRIVING _, | ae) Fic.2 MECHANICS illustrated in Fig. 1. The drum was driven with an intermittent motion and had a diameter of about 24 in. Attached to it was a slotted ring engaging the driving disk. The drum remained stationary while the disk revolved, excepting when the roller was in engagement with the slot, as shown, when the drum started to revolve at nearly the full speed of the disk. As the parts driving the disk had consider- able weight, as had also the drum, their opposing inertia forces caused a shock each time the roller struck the side of the slot. This condition was entirely over- come in the redesigned movement, shown in Fig. 2, in which the slotted ring was replaced by an internal gear, engaging a pinion which was secured to a slotted spider. A driving disk was located so that its roller engaged in the radial slots of the spider, care being taken to have the roller begin to enter the slot in a direc- tion parallel to the slot, or radial to the center of the spider. This arrangement insured the starting of the spider and drum at zero speed, accelerating to full speed, and retarding to zero again. The engaging curved surfaces of the spider and disk were slightly tapered on their faces so that, by axially adjusting the disk, lost motion was easily taken up.— R. E. Bates, Dorchester, Mass. Lock for Firm-Joint Calipers Anyone who has used calipers of the firm-jointed type knows how easily the setting may be altered when this kind of tool is being if «sive tried on the ith work. The 4h knowledge of \ \ |p this causes the user to be DISK WITH . (THROUGH HOLE CONntinually testing the setting with a scale, which, of course, takes much time. The drawing shows a sim- ple lock that will give the user of firm-jointed calipers confidence that the setting will not be disturbed by any ordinary usage. Two disks are bored out, one with a clear hole and the other with a blind one, the diameter of the holes being a snug fit over the joint washers. A piece of drill rod or cold- rolled stock is bent as shown, the two A DISK WITH BLIND HOLE CALIPERS Yeo DRILL ROD

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POPULAR MECHANICS ends entering holes in the through-drilled disk, while the disk with the blind hole has slots cut in the edge to fit the rod. A tapped hole in the center of the bent rod receives a small knurled-head screw for tightening after adjustment. When the attachment is made as described, it is placed on the caliper and the ends of the drill rod riveted over, thus making it a fixture, with no possibility of loss. It will immediately be apparent that the lock is out of the way and will not interfere with the full capacity of the in- strument. When the calipers are set to the required dimensions, a slight turn of the screw tightens the two legs firmly to- gether. The depth of the blind hole should be such that its bottom will not touch the face of the washer, in order that the pressure may fall on the caliper legs only. Combining Grinder Light and Switch The usual practice of placing a sepa- rately controlled light over the tool grinder results in considerable wasted current, be- cause the per- son using the machine gen- erally forgets ~ to turn off the light when fin- ished with the grinder. A simpler meth- od, and one which makes 4 itimpossibleto a start or stop the grinder without turn- ing the light on and off, is shown in the drawing. The |, 7% “We switch that Yip controlsthe | :, grinding-wheel motor also controls the lamp, as the light circuit is tapped into the one supplying current to the motor. When the user throws the switch to stop the grinding wheel, the light is extin- guished.—G, A. Luers, Washington, D. C. RK Ls ———— \ 7 } . Wi = @.No plates or bars of steel or iron should be worked at a blue or black heat; the material will stand far more strain worked either red-hot or cold. At an interme- diate point, great risk is run, as strains will probably be induced that will pro- duce rupture later on. Making Stereotype Matrices from Type Forms Country newspapers equipped with plate-casting boxes can make their own stereotype matrices by a simple method that has been worked out with satisfac- tory results in the composing room of a Minnesota paper. Lock up the type in any job or cylin- der-press form. Cut a piece of me- dium-weight blotting paper to the exact size of the casting box. Place the blotting paper on a felt or rub- ber blanket, blotter on top. Take an im- pression and the type form will be pressed into the blotter in the form of a matrix. Too much pressure will crack the blot- ter and spoil it, and too light an impres- sion will leave the matrix too shallow for the casting of a good plate. Strips of strawboard, pasted behind the places on the matrix that correspond to white por- tions in print, will keep the open parts of the plate from being too shallow and smudging up on the impressions made from the plate. Composing-room foremen will find it possible and profitable to set up in this way business cards, small advertisements, and similar matter that run for consider- able periods without change—J. Harold Curtis, Columbia, Mo. RUBBER BLANKET OR ELT BLOTTER PRESS ~) BED. TYPE , FORM ¥ PRESS BLANKET Cutting Glass with a Soldering Bit For cutting glass when there is no glass cutter at hand, a heated soldering bit or any other piece of heated brass or copper can be used. The edge of the glass to be cut is nicked, and the solder- ing copper, very hot, is passed above the section of the glass to be cut. Then, starting at the notch, the bit should be drawn slowly across, keeping just ahead of the crack that will follow the hot iron. With practice, fairly accurate cuts can be made, but it is advisable to practice the method on a worthless piece of glass before undertaking to cut an expensive sheet.

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POPULAR MECHANICS Two Simple Machine Guards \nything that protects the operator of a machine from injury without interfering with production is well worth while, and flying into the operator’s face, but the hands are kept from contact with the re- volving cutters. The other picture shows a small wire guard which is so placed around the die of a punch press that the Left, Guard for a Milling Machine That Prevents Chips from being Projected into the Operator’s Face and Keeps His Hands from Contact with the Cutters; Right, a Safety Guard for Punch Presses That Prevents the Operator from Getting His the photographs illustrate two such safety devices that have been found quite efh- cient. The first picture shows how the cutters on a milling machine have been covered so that not only are chips prevented from Sponging Wood before Staining There are a number of advantages to be claimed for sponging wood before it is stained. First, the action of the water, which should preferably be cold, raises the grain of the wood, so that after sub- sequent drying, this raised grain may be leveled off with sandpaper, thus doing away with its recurrence upon applica- tion of the stain. Hot water should not be used on veneer work, since it may strike through and loosen the glue on the cross-banding. With any work, it is best to play safe and use cold water. The second advantage in sponging lies in the fact that the water opens the pores of the wood, relieving them of the clogged condition resulting from previous sand- ings, and so enables the staining material to be drawn deeply into the wood, thereby producing a very even color, which is capable of withstanding light sanding Fingers under the Descending Ram operator cannot possibly get his hand un- derneath, and, of course, he would never want to put it over the top. This partic ular type of guard saved so many fingers that it was installed on all the punch presses of the firm using it. with fine sandpaper, if such should be necessary to produce that perfect smooth- ness of surface upon which the subse- quent varnish coats depend for their beauty. The last big advantage is also the re- sult of opening the pores, and this has to do with the use of a filler previous to varnishing. If the wood is filled without sponging and sandpapering previous to staining, the old sandpaper dust and other material which clog the pores will ab- sorb water from the stain and remain in a condition considerably more damp than that portion of the wood in direct con- tact with the air. When filling is now attempted upon such a foundation, this material in the pores dries out through the absorption of the water by the sur- rounding wood, with the result that shrinkage and settling develop, causing the varnish coat to be pulled down into the pores.

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POPULAR On the other hand, the same moist con- dition in the pores of the wood may re- sult, in some cases, in the varnish being forced out in small spots, due to expan- sion of the moisture if the varnish work is done in an excessively warm room. Why Pumps Become Air-Bound Under atmospheric conditions water contains about two per cent of air. When subject to a lower pressure than that of the atmosphere, the air expands, and when given sufficient time, as while the water is flowing through a long suction pipe, the air will escape from the water in small bubbles. These bubbles will stick to the pipe or pump surfaces, or the air will gather in the pockets of the pump spaces. The trouble can largely be pre- vented by increasing the head of the suc- tion supply and by operating the pump more slowly, so that the pressure of the suction water in the pump cylinder will be higher. Driving Unit for Banding Motor Generators deal of motor- a west- Having experienced a great difficulty in turning over large generator armatures for banding, ern electric railway built the device shown in the photograph. The driving unit, a 600-volt variable-speed motor, is controlled by a portable rheostat. Con- nected to the motor is a_ three-speed A Western Electric Railway Uses the Portable Arrange- ment Illustrated to Turn Motor-Generator Armatures for Banding. It Consists of a 600-Volt Motor Con- nected to a Three-Speed Transmission transmission, the lowest ratio being slow enough to turn the heaviest armature over for banding. The entire arrange- ment is mounted on a wheeled truck so that it can easily be pulled to any part of the shop where its services may be needed—Hyman M. Fink, Los Angeles, California. MECHANICS 455 Safety Attachment for Printing Press A common accident in printing shops where platen job presses are used is the crushing of a feeder’s fingers between A Safety Device for Platen Printing Presses That Forces Out the Pressman’s Hand Before It is Caught between the Platen and Type Form the chase and platen, because he did not withdraw his hand fast enough. A Penn- sylvania concern has equipped a press with a safety device that prevents acci- dents of this character. A wooden bar is mounted outside the upper platen band, on adjustable metal strips. These strips are attached to rods at the side and are adjustable vertically. The side rods are provided with cam rollers, and attached to the sides of the press in such a manner that, just before the platen closes on the type form, the connecting rods between the platen and gears that operate it, strike the cams and elevate the wooden bar. The pressman’s arm and hand, if not previously removed, will be forced out of the press before they can be caught between the form and platen—Armstrong Perry, New York City. Carburetor Leakage That dirt and grease on the outside of some types of automobile carburetors may cause leakage and dripping is rarely suspected. However, this is possible, and occurs in numerous cases. At the top of the float chamber of the carburetor is a small vent that must be kept open in order to permit the escape of air, and so allow the incoming gasoline to raise the float. When this vent is closed, the air is trapped in the upper part of the cham- ber, and as the air pressure will not allow the float to rise and shut the needle valve, the gasoline will continue to flow. When the carburetor develops flooding, before replacing or overhauling, inspect this vent for dirt, as, in many cases, nothing more than this is wrong.

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TESTING MOTORS, GENERATORS, and TRANSFORMERS By KENNETH C, COGGESHALL Part II—Generators and Transformers O determine what is known as the external characteristics of a _ gen- erator, that is, the variation in terminal voltage with an increase or decrease in load, connections are made as in Fig. 8, which shows a shunt-wound dynamo un- der test. The generator must be driven at constant speed during the test, and this should be the speed shown on the nameplate. The field rheostat, once ad- justed, should not be touched again dur- ing the test. A water rheostat, lamp bank, or other device capable of being adjusted, should be used to vary the load by steps, from 0 to 150-per-cent load. At each step, readings of the meters should be made, recorded, and plotted graph- ically, as shown in Fig. 9. The line drawn through the points representing the read- ings indicates the trend of the terminal voltage under varying loads. The char- acteristic curve of a series-wound or over- compounded dynamo will rise above that of a shunt-wound dynamo. The power necessary to drive the gen- erator is: EXxI Hp. =—— 746 X Efficiency If the efficiency is not known, but the power necessary to drive the dynamo is, then EXxI Efficiency = ————— 746 X Hp. Figure 10 shows the connections for testing the output of a three-phase a.-c. generator. Only one set of instruments need be used, if a switching system is used to connect the meters in the various phases in quick rotation. During the test the field current should be kept constant. An external characteristic curve should be plotted, as in Fig. 9, from the data recorded during the test. The load, if the test is conducted in the laboratory, may be a water rheostat or lamp bank; if the regular commercial load is used, the test may be of longer duration. The average current flowing in each phase is: ha Lith+ls | 3 that is, the average value, I, is obtained by adding the readings of the three am- 456 meters and dividing by 3. the average value of E, Fi+ E2+ Es 3 The power output is: : EXI1X 1.73 x Pi. rhe horsepower required to drive the generator, when the efficiency of the machine is known, is: EX1X 1.73 x Pf. Hp. = ———_—__— 746 X Efficiency and, consequently, Hp. X Efficiency XK 746 Pf. = ———_ —_—_———, Or, =; E XIX 1.73 EXIxX 1.73 Similarly, for a and EX1X1.73X Pf. P Efficiency = ————_——————— = - -* 746 X Hp. 746 < Hp. It is a good plan to measure the oper- ating temperature of a motor or gener- ator, to make sure that the insulation is not in danger of injury by heat. Place the bulb of a thermometer in the hottest available spot on the machine, and take temperature readings while the machine is running. Continue the test until the thermometer indicates no further increase in temperature. Compare the reading with the room temperature; the differ- ence, or temperature rise, should not ex- ceed 50° C. (90° F.). In no case, regard- less of surrounding conditions, should the thermometer show a temperature of more than 90° C, (194° F.). As intimated in the preceding para- graph, the capacity of a machine depends, to a large extent, upon the temperature at which it operates. This is especially true of transformers. Insulation breaks down very rapidly at high temperatures, and weakened insulation materially short- ens the life of a transformer. To test the capacity of a transformer, suspend a thermometer in the oil in the case, placing the bulb as near to the coils as possible. An ammeter connected in the low-tension side indicates the load current, while a voltmeter shows the line voltage, as shown in Fig. 11. If the load consists only of lamps, as is preferable, then the product of the volts and amperes approximates the output. Temperature readings of the surrounding air should

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ADJUSTABLE LOAD +--+} openers t TERMINAL VOLTAGE [ VouTMETER AMMETER - DRIVING BELT DIRECT-CURRENT GENERATOR TERMINAL VOLTAGE RATED FULILOAD CURRENT | LINE | | CURRENT * + +++ + ae in te + | + | | t ae ++ | SHUNT-FIELD —+—+ - | RHEOSTAT i Lj je aol 60 100 120 140 160 160 200 CIRCUIT AMPERES OUTPUT CONNECTIONS FOR OBTAINING TERMINAL Fic.9 VOLTAGE AND LINE CURRENT FOR VARIOUS OUTPUTS Fis.8 J POWER SUPPLY SHORT CIRCUIT . ) J D.C SUPPLY aie =i IGH TENSION LOW TENSION AAW FIELD RHEOSTAT - DRIVING BELT ] > ay TRANSFORMER| VOLTMETER | TRANSFORMER , WIV, LOW TENSION IGH TENSION FIELD CIRCUIT —— VOLTMETER + AMMETER VOLT MET ers | E | AMMETER | Ee 3 3-PHASE LOAD b 4 AMMETERS VARIABLE RESISTANCE Vw aac E WATTMETER +> »>_——- : 3 I -, [ ‘ids dai POWER SUPPLY f CONNECTIONS FOR TESTING EST FOR See bine Ry - TEMPERATURE RISE TEST FOR COPPER LOSS Fic .10 Fic.11 OPEN HIGH TENSION — t J 2,200-VOLT LINE TRANSFORMER if ——— HIGH TENSION ———— ret 3 — TRANSFORMERS —+, WWW ty WV VOLTMETER ——~ ‘Se ce LOW TENSION VARIABLE RESISTANCE WAAAAAANY k 220 V. 4 § | VOLTMETER SwitcH oe i — SP.0.T : —_ LOW TENSION —1 “NE, am A \ SWITCH D AMMETER ——— L 4-110 -VOLT LAMPS ~~ _D.P.S.T. SWITCH C J IN SERIES =— ¥ POWER )} SUPPLY | «EX TEST FOR CORE-IRON LOSS TEST FOR POLARITY AND WINDING RATIOS Fic .13 Fia.14 Connections for Making Most Usual Tests on Direct-Current and Alternating-Current Generators and Trans- formers: Figure 8 Shows Connections for Direct-Current Generators; Figure 9, External-Characteristic Graph for a Direct-Current Shunt-Wound Generator; Figure 10, Connections for Testing Alternating-Current Dynamos, and Figures 11 to 14, Connections for Various Tests on Transformers 457

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458 also be taken so that the temperature rise may be determined. This difference should not exceed 50° C. (90°F.) nor should the temperature of the oil rise above 90° C. (194° F.). It is both difficult and dangerous to obtain the current and voltage values of the high-tension circuit without special testing apparatus. The efficiency of a transformer is, therefore, determined by finding the copper and iron losses; the input is, then, the output plus the iron or core loss plus the copper loss. To make the copper-loss test, short- circuit the low-voltage windings and place a voltmeter, an ammeter, and a watt- meter in the high-tension circuit, as in Fig. 12. Connections are made through a rheostat to a low-voltage power supply. Manipulate the rheostat until the full- load current, the value of which will be found on the nameplate, flows in the windings. The wattmeter will then indi- cate the copper loss of the transformer— since the transformer is doing no outside work and the power consumed is that due to the heat loss in the windings. Take other readings at various loads, and re- cord the readings graphically. The test for iron loss is somewhat sim- ilar to the copper-loss test, as indicated in Fig. 13. In this instance, the high- voltage winding is left open-circuited, and the instruments are connected in the low-tension side. Since no current flows in the high-voltage winding, the watt- meter shows the power consumed in ex- citing the iron. The wattmeter reading also includes the potential coil losses in both voltmeter and wattmeter, but unless very accurate tests are being made, these losses can be disregarded. If possible, an auto transformer should be used instead of the rheostat for vary- ing the testing voltage. POPULAR MECHANICS Knowing, now, the copper and iron losses, the efficiency of the transformer under test is: Efficiency = ———— ——_——" P + copper loss+iron loss Should it be necessary to change the transformer leads, or should there be any question as to whether the connections are correct, a polarity test is advisable. Such a test requires a transformer of equal rating for comparison. Make the connections as indicated in Fig. 14, which shows a relative-polarity test on a 2,200 to 220-440-volt transformer. The high- tension windings of both A and B are connected to a 2,200-volt power-supply circuit. Four 110-volt lamps are con- nected in series through a double-pole single-throw switch, C, with leads from the low-tension side of both A and B. A voltmeter is connected through a single- pole double-throw switch, D, in such manner that the voltage of either trans- former may be read as desired. When all is ready for the test, throw switch C and note if the lamps light brightly. If they do, the leads are brought out correctly; if not, the leads are re- versed. The latter case indicates that the transformers are opposing each other. Repeat this test on all leads until every connection is known to be correct. The ratio between the windings of a transformer may be found by making the same connections as for the polarity test. Transformer B must, however, be of a known ratio. Leaving switch C open, quickly throw switch D from one contact to the other. If the transformers have similar windings, and similar ratios, the two readings should be identical. In making transformer tests, high volt- ages are sometimes encountered and great care must therefore be exercised to insure personal safety. _ Using Drawing Pencils Always sharpen a drawing pencil at both ends; the ordinary round point at one end and a knife-edge at the other. Use the knife-edge whenever a long line is to be drawn, as it will do much more work than the round point before re- sharpening is necessary. In forming a knife-edge on a drawing pencil, always hold the pencil so that the edge will be made parallel with one of the six flats on the hexagon pencil—prefer- ably the one on which the name and grade of the pencil are stamped. This makes it easy to form the second side of the edge, for it is simply made parallel with the opposite flat of the “hex,” and the edge thus comes out straight, instead of on a slant. Thus, when the pencil is gripped by the fingers, the edge will always have the proper angular relation to the hexa- gon, bringing it instantly parallel with the edge of the T-square. Since sharpening a pencil in this way soon removes the maker’s mark, it is nec- essary to mark the pencil near the mid- dle; this is done by cutting the required number of notches near the center of the flat; that is, two notches for a 2H pencil, three for a 3H, and so forth—Curtis Ral- ston, Chicago, III.

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POPULAR Lubricating Broaches Square broaches should be pulled with a corner upward. The cutting lubricant then flows down around both sides, and does not spatter off, as would be the case were a flat surface used upward. Spline broaches should be so slotted that a chan- nel between two of the splines will be on top; the channel then serves to conduct the lubricant into the hole. Wick-Feed Oiler Made from Grease Cup A satisfactory homemade _ wick-feed oiler can be applied to the bearings of a dynamo or similar mechanism, so that the necessity of constant hand oil- ing, with the attendant pos- sibility of flooding, are eliminated. A large grease cup is screwed to the under- side of the bearing, witha piece of wicking extending through it and touching the revolving shaft. The cap of the grease cup serves as a reservoir for a liberal supply of oil. This is a simple method, for use where small quantities of oil are required, and where excess oiling is to be avoided. DYNAMO- Special Trowel for Concrete-Road Work Concrete workers on road-paving con- tracts are familiar with those jobs in which a groove, or flangeway, must be molded on the inside of street-car or railway tracks, in order to provide clear- ance for the flanges on the car wheels. The drawing shows a type of trowel used on one such contract, for forming the flangeways. A single block of wood is used for the trowel, which can be cut out on a bandsaw or formed in a pattern shop on a shaper. TROWEL Ree. ‘ MECHANICS Lifting Check-Valve Balls The drawing shows clearly how a small meta! ball can be removed from its posi- tion in a ball-check valve, or other posi- tion where it is inaccessible to the fingers {I or ordinary 7: tools. Nothing more than a piece of rub- ber tubing, such as can be bought at any drug store, is needed. The rubber tubc can be used alone or it can be fitted with a small piece of metal tubing in each end, as shown in the draw- ing, for handling balls smaller than the diameter of the rubber tube. In use, the operator places one end of the tube in his mouth, the other end being in firm contact against the surface of the ball, which is drawn up and held tightly against the tube by suction.—C. A. Clark, Miyazaki, Japan. Drilling Tempered Springs After attempting to drill a %-in. hole through a number of tempered springs with no better success than a number of broken drills, an observant me- chanic noticed that the lips of the drill would - still cut, even when the center was dulled, and an idea being sug- gested by this, he proceeded to put it into execution, with satisfactory results. In order to bring the lips of the drill into contact with the metal, the point of the drill was ground off square so that when set into the punch mark the drill immediately began to cut. The drill was run at slow speed, and, when it stopped cutting, was raised from the work, a heavy center punch used to make another depression in the center of the hole, and the drill fed down again. By alternately punching and drilling in this manner, the steel was finally drilled through—E. K. Wehry, Cedar Rapids, Ia. CENTER- PUNCH « MARK, POINT GROUND OFF

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460 POPULAR An Improved Blueprint Washer The washing of large blueprints is al- ways an awkward job because of the splashing and mess, which is impossible SPRAY PIPE PRINTS —— SUPPLY A Blueprint Washer That Uses Nothing but Clean Water to Develop the Exposed Prints, and Elim- inates the Need of Using Trays and Sinks to avoid when large trays are used. Also, owing to the size of some of the trays and the inconvenience of emptying them, they are not uncommonly left for a long time full of dirty greenish-yellow water. The washing device illustrated does away with the tray or sink, as the wash- ing is done entirely by a flow of clean water over the print. An inclined table, which is built in any convenient location, is provided with raised sides and a trough at the bottom for carrying off the excess water, the whole being covered with sheet zinc or lead. A water pipe, which is drilled with a series of small holes, is arranged parallel with the top of the table so that there will be a uniform flow of water over the surface of the prints.—B. Francis Dashiell, Dunkirk, Md. Testing for Vibration in Buildings In a western city, a reinforced-concrete building had but recently been completed when the plastering began to fall from the ceilings. The owner claimed that work was not according to specifications, and the contractor asserted that the trou- ble was the result of vibrations, which were caused by trolley cars crossing a frog in the street just in front of the building. As none of the vibrations were heavy enough to be seen or felt in the four-story building, an engineer solved the problem and traced down the trouble in a novel manner. A shallow bowl of me- MECHANICS tallic mercury was placed on the floor of the top story, in such a manner that the mercury would be in direct sunlight. Those interested in the result of the test stationed themselves at a window and watched. A reflection from the sun was thrown onto the ceiling by the mercury and as the street cars passed, it was no- ticed that the reflection on the ceiling moved several inches, thus greatly mag- nifying the movement of the building and vindicating the contractor.—J. R. Linton, Sioux City, Ia. Curing Slapping Exhaust Valves Sometimes, when a Corliss engine is running under a light load, a slapping noise will be heard from the exhaust valves. Examination of tht indicator dia- grams will usually show that, under light load, the cut-off is very short, and expan- sion is carried to a pressure below that of the atmosphere. The exhaust valves are then forced from their seats, causing the slapping or chattering noise. The steam should be throttled, or the boiler pressure lowered, and the cut-off made later in the stroke, so that the steam will not be expanded below atmospheric pressure. An Adjustable Bench Stop A bench stop, which can be adjusted to any height, or lowered so as to be flush with the top of the bench, is quite easily installed on any bench in the manner illustrated. A square hole is cut through the bench, in line with one of the legs; this hole is for the piece of oak that forms the stop proper. A fiat- iron lever is next made; twist one end of this to lie flat, drill a hole for a capscrew, and solder or braze a nut underneath. Drill two other holes in the lever—one to pivot it to the bench leg and the other to fasten it to the lower end of the stop. This latter hole should be slotted, so that the stop will be moved upward in a straight line. Fit a bolt into the nut on the lever, then bore a blind NUT SOLDERED TO LEVER

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POPULAR hole in the underside @f the bench, to receive the capscrew head, and screw a wooden block, with a hole for the screw shank, below it. Drill a small hole through the bottom end of the bolt for a turning lever, which may be a piece of stiff wire or a nail. To raise or lower the stop, it is only necessary to turn the screw either to the right or left—L. B. Robbins, Marwich, Mass. Polishing the Ends of Pins The appearance of pins with round or spherical ends will be greatly improved if the ends are well polished. It is a diffi- cult matter to get a good polish by hold- ing the emery cloth with the fingers while the work is revolved, because it is im- possible to hold the cloth. perfectly steady, with the result that fine grains of the abrasive cross and recross the surface, producing a scratchy appearance. To obtain the best re- sults when using emery cloth, it should be held, if at all possible, in some kind of rigid holder of the type illustrated. <A holder of this kind is merely a piece of cold-rolled steel which is turned down to a handy diameter to fit into a drill chuck. A hole of the same diameter as the work is drilled in the cen- ter, and another hole, of a diameter that will conform to the radius of the end of the pin, is drilled at right angles to and intersecting the first hole, as shown. A strip of emery cloth is inserted into the side hole and moved along as it becomes worn. This method gives a very high polish quickly and easily, and is well worth the trouble when a quantity of work is to be finished. GRIPPED IN DRILL CHUCK HELD IN TAILSTOCK Presses for Straightening Bent Fenders The drawing shows two devices that can be used to advantage for the quick and easy removal of dents from fenders, or any other sheet-metal work to which they can be applied. The upper tool is made entirely of 14-in. flat iron to the dimensions shown. The tight joint indicated should be very solid and should be riveted, although a nut MECHANICS 461 and bolt will hold it sufficiently tight. Downward pressure on the hand lever gives a powerful compression at the ends of the jaws. Any width of fender or any curve can be restored to its original shape FENDER —— yx 4*x19" IRON HAND LEVER , ROUND-IRON BAND S'HAND SCREW OAK MAPLE 2"x ax 24" Two Convenient and Simple Tools for Pressing Out Bumps and Dents in the Fenders and Bodies of Automobiles and Similar Sheet-Metal Work by inserting hardwood blocks of the proper size and shape between the jaws and the work. The lower tool is made from hard- wood, with a handscrew at one end which serves to press the outer ends of the members together with sufficient force to flatten out practically any dent. Notches are cut in both members, to permit changing the position of the round iron band holding them together, so that the tool can be adjusted to fenders of dif ferent widths. The thrust of the screw is taken by an iron plate, screwed to the lower member, Size for Porous Walls A good size for preparing walls for papering or calcimining may be made by dissolving 1 lb. of glue in 1 gal. of boil- ing water, as in making ordinary size; dissolve also 1 Ib. resin soap (yellow laundry soap), cut in thin slices, in 1 gal. of boiling water; then 2 lb. of alum in 2 qt. water. Thoroughly stir together the glue and soap solutions, then add the dis solved alum. This makes about 3 gal., which will require 2 gal. of water to thin to the proper consistency for a porous wall, and still more water for a hard surface. One or more applications should be put on, as hot as possible. This siz is more resistant to moisture than ordi nary size—A. MacCullough, Chicago, III.

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POPULAR Adjustable Planer Vises Many jobs that are machined on the planer could be done better, and in less ’ /- CORED SLOT MOVABLE JAW N STATIONARY JAW | ILECHANICS upon the thickness and length of the work; they can be bolted anywhere on the table so as to hold odd-shaped work at any angle. The length of these vises is left entirely to the re- quirements of the user; some will prefer them made to the width of the table, and others will not want them quite so long. The body and station- ary jaw are cast in one piece from a simple pat- tern, the resulting cast- ing being machined on the top, bottom, and face ! Lep!'s| WASHER ~ 4 DETAILS OF MOVABLE JAW of the jaw. On the top face of the jaw slide, a number of key slots, 4 by 4 in., are cut, 14% in. apart. NG The sliding, or mov- pea Rit able, jaw is built up in two parts, the front mem- ber being the real jaw, while the rear fiece serves as a buttress, and as a nut for the clamping screws. The rear block is shaped so as to overhang Adjustable Vises for the Planer, That Make It Possible to Set Up and Remove the Work Quickly with a Considerable Time, Particularly on Repetition Work time, if the work were held in vises in- stead of being bolted to the planer table. The work is generally bolted to the table because suitable vises are lacking, the only ones available being generally of too limited capacity for wide work. The drawing shows a type of planer vise that permits rapid set-up, which is an advantage when several pieces of the same kind are to be worked. Fora planer having an 8-ft. stroke, three or more of these vises should be used, depending and slide on the tongue of the front member, and serves to hold the latter down to the slide. The countersunk screw seat is the only means used to hold this loose jaw centrally, which is free to float, to adjust itself to the face of the work. The rear part of the sliding jaw has a tongue that fits into the slot in the base, to which it is loosely clamped by a screw or bolt, as shown. The key, which fits loosely, is used to form an absolute buttress and prevents the jaw from sliding backward while the clamping screw is tightened—J. V. Ro- mig, Allentown, Pa. Saving in Testing New Refrigerating System When testing a new installation of coils in a refrigerating system, a small, port- able, air-cooled, motor-driven air com- pressor is used to provide the necessary test pressure, which, depending upon the contract specifications, runs up to 200 Ib. and over. A suitable connection is made between. the coils and pump for the in- sertion of a high-pressure-gauge, and also an ammonia-charging valve. Pressure is pumped into the coils, using fresh air, for the first test. If there are any serious leaks, they will be detected immediately by the hissing of escaping air. Should there be no such leaks, watch the pres- sure gauge and see whether the pressure falls very much, remembering, however, that a slight fall in pressure will accom- pany the cooling of the highly com- pressed air. After this slight drop, which should take place within a half hour, the pressure should remain constant. If this test is satisfactory and the pressure stands up well, discharge the air, and connect a drum of ammonia to the ammonia valve between the air pump and the coils, and allow a small amount of the ammonia to escape into the closed-up system, enough

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POPULAR MECHANICS to raise the pressure to about 10 lb. This amount of ammonia will be sufficient to make the detection of any leaks, no matter how small, possible. Now, pump the system to 200-lb. pressure again and go over all the joints, smelling for the sharp ammonia odor, which will escape through any porous or leaky spots. Leaks come from badly cut pipe threads, poorly cemented joints, bad seams in the piping, porous and honeycombed spots in the fittings, and from cracked fittings. If.the second test is successful, dis- charge the ammonia-laden air into the open, and pump a vacuum in the coils, before filling the system with the full am- monia charge. Small leaks are sometimes closed by peening the metal with small punches and ball-peen hammers. Another way consists in pumping a strong vacuum and smear- ing the leaky spots with a thin mixture of glycerin and litharge, which has a tendency to be sucked into the holes and porous parts, closing them when the lith- arge sets. Soldering may also. be resorted to, but never with the system under pressure, A Novel Scale for Machinists A new die, having 16 threads per inch, was being tested out on some 4-in. drill rod, the result being an exceptionally fine- cut thread. A few of these threaded rods were made into 6-in. scales by one of the machinists in se the shop in the following manner: Two steel blocks were drilled and tapped fora 44-16 screw and then cut down at the ends, as shown in the drawing, to about half the diameter of the rod. The threaded rod, resting on the steel half-blocks, was placed on the magnetic chuck of a _ surface grinder, and faced down flat. After grind- ing, the rod was removed from the grinder, graduated with a very sharp chisel, and marked with small figures. The half-blocks were moved along, as in- dicated by the dotted lines, to serve as anvils for the rod during the graduating. The threads, being 16 to the inch, take the place of %e-in. graduations, and the chisel marks are 4-in. apart—M. E. Duggan, Kenosha, Wis. Ball-Bearing Puller A puller for inner races of ball bear- ings, that is different from the usual de- vice, is built on about the same principle |

BALL-BEARING PULLER 7 INNER RACES TO BE REMOVED — —< [7 | td | Vth

A Ball-Bearing Puller That Embodies the Principle of a Lathe Collet, Holding the Inner Race While the Screw is Turned, to Force the Shaft Out as a lathe collet. As the puller can be made for use on bearings of different sizes, no dimensions are given in the drawing, which clearly shows the con- structional details. The inner part is machined, as shown, with split jaws. The largest diameter of this part is tapered so that the-similarly tapered and threaded sleeve can be screwed down to tighten the jaws of the puller on the bearing race. A long screw at one end of the puller bears against the end of the shaft; when this is tightened the race is pulled off.—J. Magis-Frank- art, Ouffet, Belgium. Belt-Loop Hammer Holder Carpenters, and others who must al- ways have their hammers within easy reach, or those who work with two styles of hammers, will find the hanger shown in the drawing to be of great utility. All that is required to make such a holder is a piece of leather, about 3 by 4 in., which is pierced with a hole for the hammer handle and slitted to fit over the belt—A. C. Cole, Chicago, Il.

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Planer-Tool Lifter When a machinist is working at piece rates on duplicate production work, every little trick to preserve the cutting edge WIM A Lifter for Planer Tools That Prevents the Tool from Rubbing on the Work on the Backstroke, Thus Preserving the Cutting Edge of the Tool of his tools helps to put money in his pocket. As everyone knows who is familiar with planer tools, the rubbing of the cutting edge on the return stroke soon makes resharpening necessary, and many operators lift their tools on the backstroke by hand, just to eliminate this dulling action. While there are many devices for the automatic elevation of the tool above the surface of the work, the one shown in the drawing is among the simplest and most effective, as it is easily made and quickly clamped to any cutting tool. The body is made from a piece of flat steel; it is fitted with a latch, which has a form somewhat similar to that of the cutting tool and is held to the body by a bolt or rivet. By rounding off the top corner, this latch will drag behind the tool on the forward or cutting stroke, but will fall in a vertical position on the return stroke. When the lifter has been adjusted to the proper height, it will cause the tool to rise on the return stroke, as shown. Making Good Brazed Joints A method which adds strength to a brazed joint, in either tubular or plate work, consists in drilling one of the parts with a series of holes, at the point where the braze is to be made. Ordinarily the practice is to apply the spelter and flux to the pieces and then heat until the spelter flows and runs into the joint. Lack of heat, or dirt in the joint, will cause an POPULAR MECHANICS imperfect union, that cannot be detected from the outside. Drilling the holes, as suggested, and applying the spelter to this portion of the joint, causes the melted brass to enter between the surfaces where it is desired. The size of the holes de- pends, of course, upon the size of the job, but ordinarily holes not larger than 4 in. should be used; these can be filled with spelter and finished to present a smooth job. This method has been satisfactorily used in brazing automobile-axle housings. Beveling Edges of Wallboard In working with wallboard, it is some- times desirable to bevel the edges to form a neat joint; this can be done without sawing, which generally leaves ragged edges, by means of a simple device that uses sandpaper for forming the bevel. A piece of wood, about 6 in. square, is cut di- agonally to make WALLBOARD BEIN BEVELED ) two 45° § trian- gles, and these a are fastened to- li A gether by two UF Hanove braces, as shown, a handle also be- ing provided. A piece of wallboard is nailed to the hypot- enuses of the triangles, and the sandpa- per is fastened to this with thumbtacks. In use, the sanding device is moved back and forth across the edge of the panel, and, by raising or lowering the panel, the whole surface of the sandpaper can be used.—Karl L. Martin, Cleveland, Ohio. WALLBOARD COVERED WITH LAYER OF SANDPAPER Spring Circular-Saw Guide When the circular saw is used to split narrow stock, the simple spring holder shown in the drawing will enable the operator to do his work faster and without danger of having a finger cut off. Such a holder is made by bolting a piece of ¥y by %-in. spring steel between blocks of hard- wood. The length of the spring will vary with different saw tables, but 12 in. is about the average. A piece of stock is set against the saw guide, and the spring holder is clamped in

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POPULAR MECHANICS place on the saw table with a C-clamp, in such a manner that the spring presses firmly against the stock. Make certain that the extreme point of the spring can- not come into contact with the saw itself. A similar spring can be used to press downward on the stock, in which case the holder would be clamped to the saw guide, and the steel spring would be adjusted to press on the wood between guide and saw. With two such guides in position, the stock can be sent through the saw from one end to the other without carrying the hands beyond a safe distance from the saw. Once started, the man “taking away” can pull the stock toward him and at the same time be certain that the wood is bearing hard against the saw guide.—E. L. Bragdon, New York City. Rustproofing Iron A new method of rustproofing, which has been applied especially to small auto- mobile parts, consists in boiling the ar- ticles in a solution of hydrophosphate of iron. An attractive dark-gray finish is produced, and this is practically proof against all attacks of rust. The process is more rapid than others, and there is no effect upon the strength or temper of the metal. Artist’s Magnifying-Glass Holder An artist’s ability to do fine work on a drawing, such as producing a fine stipple with pen or pencil, can be greatly in- creased by using a 3-in. reading glass. Besides, the eyes are re- lieved of a great deal of strain, and the pen can be more accu- rately guided. The drawing shows a wire support for the magnify- ing glass, which is slipped underneath the edge of the drawing board and can be instantly removed. The support can be made to any suitable measurements from stiff wire, and is adjustable horizontally and vertically. The magnifying glass has a hole drilled in its handle to make a tight fit over the wire, as shown in the drawing. WIRE READING GLASS 465 Discarded Vise Makes Arbor Press Scrapped on account of a broken jaw, an old vise was made to serve in the capacity of an arbor press, the device ARBOR HOLE PART OF OLD VISE SLIDING JAW RAM Discarded Because of a Broken Jaw, This Vise was Made into a Substantial and Quick-Acting Arbor Press for Work within Its Capacity proving very quick and solid. Two pieces of 34 by 21-in. flat steel are used for the sidepieces, which are fastened to the fixed part of the vise by screws. One end of each piece is bent at right angles and fits around the vise, to give extra strength and rigidity. Next, a piece is made that serves as the arbor plate of the fixture; this is a 3 by 3-in. piece of machine steel, the length of which is such as to fit easily between the sidepieces. It is bored in the center for the arbors to slip through, and each end is drilled and tapped for %4-in. bolts. To make the press quick-acting, holes are drilled in the sidepieces at intervals of about 2 in., and slots are cut at an angle, as shown. From the drawing it will be seen that the part bored to take the arbors is free to revolve, and that, consequently, the arbor can be inserted in the hole while in an upright position, thus lessening the dis- tance necessary between this part and the end of the vise ram. This feature, in conjunction with the freedom with which the piece can be dropped into any convenient slot that the length of the arbor may call for, makes this press quite rapid. For small arbors, a bushing is made to fit the hole. When the whole fixture is assembled, it should be bolted securely to a bench, preferably one mount- ed on wheels, so that it can be moved around the shop. @ Nails and screws dipped in grease, wax, or soap will drive more easily, particu- larly in hardwood.

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466 Truss Stiffens a Long Ladder The use of long ladders, such as fire ladders, is only made possible because of a system of trussing, which can be mn ‘ EYEBOLT — Yq ROD if My at Ip 119047 py | + wil sp ip | i Trusses on the Underside of a Long Ladder Prevent It from Swaying and Swinging and Give a Sense of Safety to the Worker My ae i | J we eee — adopted, in a modified form, for stiffening other long ladders and preventing them from swaying. Four eyebolts are made, large enough to permit a 14-in. rod to be inserted through the eye, which should be about 4 in. away from the underside of the ladder. Four pieces of 14-in. mild steel are used for the trusses, and each of these is about half the length of the ladder itself; one end of each is flattened and drilled for heavy screws, the other ends of two lengths are threaded with left-hand threads, the other two being threaded right-hand. Turnbuckles are fitted to each truss after the ends have been passed through the eyebolts. With each side of a long ladder braced as shown, practically all spring will be eliminated, and it will be sufficiently strong to be used in many places where otherwise it could not be considered.— Lowell R. Butcher, Ames, Ia. A Cheap Board for Large Drawings The high price of a large drawing board and the still higher price demanded for a large-size drawing table are items that must be seriously considered when the board is required only for some special piece of work. An idea that represents an economical and practical solution makes use of a variety of wallboard that can be POPULAR MECHANICS obtained in panels of almost any dimen- sions up to 4 by 12 ft. The type of wall- board best suited for the purpose is that which is built up of wooden strips, ce- mented together to make a continuous board, with a smooth surface of tough brown paper. The cost of this material is but a few cents per square foot. Wall- board of this kind is made 14 in. thick, and the large panels are therefore flexible and should be well supported when used horizontally; when used vertically, this is unnecessary. A _ standard %4-in. metal channel, fitted to the edges of the board, makes a fine sliding edge for the T-square. —C. Nye, New York City. Making Smooth Joints in Large Tile Where firmly cemented joints are re- quired in lines of large sewer tile, several difficulties are encountered unless an un- necessarily large quantity of cement mix- ture is used. If a dry, coarse mixture is used, it will be hard to make an ab- solutely tight joint, and if a thin, rich mix- ture is used it will flow through the joints. The latter is, of course,the better mix- ture, as it will flow and fill in below the tile without : tamping or the use of a great amount of the cement mixture, and will make a good joint if some means of. confining it is used. This is easily done. Having placed a new section of tile in position and cen- tered it by means of small bits of stone or like objects, placed between the socket of one pipe and the end of the other, take a narrow strip of some thin springy mate- rial—wallboard is excellent—and shape it to the inner curve of the joint to be cemented. The ends of the strip should butt closely together; if this retainer ring is correctly made, it will hold itself in place, but light sticks, a trifle longer than the diameter of the pipe can be sprung into place to help retain it. With the aid of this device, a very thin cement mix- ture can be poured about the joint, into which it will flow, filling it completely and showing a smooth inner bore when set. —Louis Schneider, Clinton, Mo. RETAINER \

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tI! i i ns AR = = nn pa Information as to where to obtain any specified materials or parts for making objects described in the following pages may be had, on request, from our Bureau of Information.—Editor. Concrete Boat Landings and Docks By A. C. COLE BOAT landing at the summer home, or resort, is something that is fre- quently lacking, and in most cases where one exists, it is, as likely as not, a rickety structure supported on a few half-rotted posts. Such a landing is not only unsafe but unsightly, requires frequent repairs, will be required to build the necessary wooden forms, but once constructed, the job is practically everlasting, and repairs are seldom if ever necessary. The drawing shows four types of land- ings and docks; dimensions are given for three, and all are suitable for the accom- a = [SUP LANDING FOR 1 _MOTORBOATS _ PLAN WATER LINE) = +12” +o pe =| |TYPE OF LANDING |__4 (ree BN ne AND BOAT DOCK, SHOW ING. NOSE {PLAIN T TYPE “Ors BOAT “LANDING fs Concrete Boat Landings Never Become Rotten like a Wooden Structure, Seldom Need Repairing or Re- building, and Are Practically Indestructible Unless Carried Away by Ice or Flood and, from time to time, rebuilding. The disadvantages of wooden structures can- not, however, apply to a boat landing made of concrete. A little more work LANDING _FOR ROWBOAT | WIRE-MES) ” REINFORCING Wye —s-O——+ ~— 10" re) -s 10:0" STEEL RAILS PLAN pi2 eS WATER LINE, + oe sty: 2 Pt yi ELEVATION modation of the Neither the styie nor dimensions need be adhered to, of course, altered in any way desired. boat. given but can be average small 467

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468 POPULAR In the construction of a boat landing, as well as in the building of any other mono- lithic structure, a form is required to contain the concrete mixture until it sets. A form for the construction of work of this character is made by driving boards or sheet piling into the bed of the stream, to form a hollow, into which the concrete mixture is poured and tamped. In making the form, care should be taken to have it well braced, so that the weight of the con- crete will not force it apart. Also, the boards forming the sides of the form should be close enough together to pre- vent a free flow of water through the form, as this would have a tendency to wash away the cement binder, leaving an imperfectly bonded mass consisting largely of broken stone. It does not make any particular difference whether or not there is water inside the form; if it can be pumped dry, all the better, but this is not necessary. The concrete will harden under water, although at a slower rate than when exposed to the air. The mixture for work of this kind should consist of at least 1 part cement, 2144 parts sand, and 5 parts of crushed stone or screened gravel. A little more cement than the above quantity will not hurt, however. All the ingredients should Automatic Stock Tie Although the knotted rope is the oldest tie for stock at the manger, it is not always the most convenient, for, with mittened hands, it is difficult to tie the clumsy rope into a knot that will hold. Again, as the rope becomes worn at the knot, it breaks at that point before the remainder of the rope shows appreciable wear. To save the rope and make the tying and untying prac- tically auto- matic, the de- vice shown in the drawing can be made and attached to the man- A-hole is drilled in the front of the manger and a plug is made, so tapered that its larger diameter will just fit into the hole. A notch is cut in one side of the plug to hold the rope, and a strip of ash, or some other springy wood, is used ger. MECHANICS be thoroughly mixed before adding water, and when the water is added, the mass must be mixed again until every stone and grain of sand has its coating of cement. In this manner the strongest pos- sible mass will be obtained once the cement has set or hardened. The estimated materials required for landings of the style and dimensions shown are: for Fig. 1, cement 38 bbl, sand 1434 cu. yd., and stone 29 cu. yd.; and for Fig. 2, 331% bbl. cement, 12.8 cu. yd, sand, and 251% cu. yd. of broken stone. The plain type of landing shown in the lower left-hand corner is built to meet in- dividual requirements, and no dimensions or estimate of materials are given. The rather elaborate style of Fig. 3 is built in two parts, which are connected by means of a reinforced runway above the water line. The nose of the outer pier is pointed upstream to break up floating blocks of ice, and the inner pier is cast hollow, being afterward filled in with well-packed earth. The materials required for this landing, built to the dimensions given, are cement 46144 bbl., sand 18 cu. yd., crushed stone 35 cu. yd., woven-wire mesh, 3 sq. yd., and old steel rails, 60 ft. Eye- bolts and rings, for tying the boats to, are imbedded in the concrete as shown. to attach the plug to the manger by means of a bolt, as indicated. To make the rope fast, it is simply passed through the hole by pushing in on the outer end of the plug. The animal is released by pushing the plug the same way and pulling out the rope—Geo. G. McVicker, North Bend, Neb. Developing Holder for Cut Films The drawing shows a film-holding de- vice used when developing the individual films of a film pack. The holder is made from a single strip of brass, alum- inum, or gal- vanized wire, formed into a number of loops into which the films are inserted in the manner indicated. The ends of the holder are bent upward, and a hook is formed in the extremity for suspending it from the edges of the tank containing the developing solution.

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POPULAR MECHANICS Removing Tight Screw Caps When the screw cap of a fruit jar, or similar container, refuses to move, the following plan is frequently successful in getting it started: Get a strip of sand- paper, twice as wide as the screw top and long enough to reach entirely around it. The sandpaper is folded lengthwise of its center, with the abrasive side out, placed around the outside of the cap, and tied in place with a stout string. Pass the cord around several times, drawing it as tightly as possible, and end it in a loop. Into this loop a stick, or similar lever is inserted, the end of which, pressed against the top, provides sufficient lever- age to loosen it. Attachment for Glasses Aids Marksman The elderly marksman, on account of changing eyesight, often finds himself handicapped by the limitations of focus. If he uses glasses to overcome a tendency to farsighted- ness, the tar- get and front sight are clear, but the rear sight is more or less indis- tinct, and if “nearsighted” glasses are used, the target and front sight are blurred while the rear sight is clear and sharp. The little device shown in the drawing, which one sharpshooter has found eliminates these troubles, is made from a narrow piece of cardboard having a narrow slot cut in the center; it is held to the lens of the “sighting” eye by a wire paper clip—J. G. Brown, Evanston, Illinois. an =—_€ c=) PAPER CLIP A Water Popgun The only thing needed to make a safe and sane popgun is a cork large enough to fit tightly into the end of a length of garden hose after the nozzle has been re- moved. The hose is connected to the faucet and, aiming the cork as desired, the water is turned on; this compresses any air that may be inside the hose and causes the cork to be expelled violently, with a considerable “pop.”—Everett Gor- dinier, Denver, Colo. 469 Grain Scoop Made from Washboiler There are many times during the year when a scoop such as that illustrated will be found very useful around the farm. For fill- ing grain sacks it is faster than the scoop shovel, there is less danger of spilling, and it is also used with good effect in handling grain in other ways. The dotted lines show the part of the boiler which is to be cut away; the cutting should be done carefully, and, if desired, the edges may be beaded over a piece of stiff wire, which will make the scoop stronger and eliminate sharp edges. Two pieces of flat iron are riveted to opposite sides of the boiler, just back of the cut, and a piece of pipe is fitted between them to form a handle, a long bolt being used to hold it in place. When partly filled, the scoop can be carried by the pipe handle like a pail. Brackets for Spare Tire The form, of tire bracket shown in the drawing is made from short lengths of iron or steel rods, bent into shape, and threaded at one end to take a_ suit- able wingnut. The clamps are covered with rubber tubing to pre- vent chafing. When at- tached to the back of the deck of a roadster, and the cover locked down, the tire is practically secure against theft. To re- move the tire it is only necessary to loosen the nuts and turn the clamps to one side. RUBBER TUBING

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POPULAR Making the Stairs Safe for Baby To keep the baby from climbing the stairs until he can do it safely and with- out the usual danger of falling back, to the consterna- tion of the household and possible. in- jury to him- self, the false step shown in the photo- graph provides an effective barrier to the infant’s prog- ress. The step is built to con- form as close- ly as possible in appearance to the rest of the woodwork, and when placed on the lowest step, leaves no foothold for the baby. When in position, the barrier is held in place by screen-door hooks, and when the child is large enough to climb over the obstruction, he can be safely trusted to go the rest of the way upstairs. The small box in the foreground of the picture is for the other members of the family, and is so small that the baby can- not get on top of it—Uri V. Averitt, Gary, Ind.

Using Cheap Flashlight Batteries Among the small types of pocket flash- lights, the most popular is the 1% by 3- in. two-cell flat case, in which both cells are side by side. Both cases and bat- teries of this size are sold in large num- bers through novelty and five and ten- cent stores. By knowing how to fit the cheap batteries into the case properly, they may be used with results comparable with those obtained with the higher- priced ones. The cheap batteries are sold at a low price largely because they are not so accurately made. It will usually be found that, when inserted in the case, the cheap battery will rattle loosely, and this frequently results in short-circuiting the contact springs of the battery, either directly to the case, or through the lamp. When this happens, the battery rapidly discharges, and the owner may never know why his battery suddenly goes dead. After some experiences of this char- MECHANICS acter, the idea of wrapping the new bat- tery with strips of gummed tape to make a fairly tight fit in the case occurred to me. Since that time my cheap batteries have had a long life. It is, of course, also necessary to bend the battery springs so as to get the right tension and contact with the switch, but this bending does not insure satisfaction unless the battery is “padded out” to fit the case properly. Where this fitting is properly done and the usual attention given to tensioning the springs, most of the ten-cent batteries will give satisfactory service.— Curtis Ralston, Chicago, Ill.

Preventing Theft of New Tires The general custom of carrying new automobile tires in the tire rack of the car as “spares,” instead of mounting them upon the wheels and getting mileage out of them, is responsible for many tire thefts. Even when they are protected by a chain and lock, an enterprising thief can find ways and means to open the lock or cut the chain; the best way to foil him is to put the new tires on the wheels and carry the old ones as “spares.” <A new tire is much more easily disposed of by the thief than an old one, and as the thief reasons that the old one is probably of little value, he passes on to find a car attractively baited with new tires.

Chemical Crusher Made from Spoon Photographers who mix their own chemicals frequently find it necessary to crush some of the crystals in order to make them dissolve rapid- ly, and the same is true of amateur chemical ex- perimenters. The photo- graph shows how an ordi- nary ice- cream-soda spoon, one of the long-han-

dled variety, can be made into a_ very . effective crusher, which, unlike glass crushers, is unbreakable. It is only necessary to bend the spoon bowl at right angles to the handle so that the bottom of the bowl is downward.

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POPULAR MECHANICS Bottle Caps Make Good “Metal Lath” The proprietor of an amusement resort makes it a point to gather all the soda- water bottle caps which are left scattered around by picnickers. There are several reasons for this, the main one being that the caps, concealed in the grass, dull the edge of the scythes. The second reason for gathering the caps is that they may be nailed to the sides of small buildings, serrated edge out, with a shingle nail through the center, and form a good foun- dation for a coat of cement stucco. From 12 to 24 of the caps are needed to cover a square foot of surface—John Mignone, Spring Valley, Il. Agitating Negatives during Development Tray development of photographic neg- atives has one advantage over the method of developing the plates in a tank, as the tray can be rocked and the develop- ing solution agitated. However, time is often limited, and it is desirable to develop the negatives in a tank. The photograph shows a meth- od of devel- oping the plates in a hard-rubber or vul- canite tank in which the developing solution is agitated by a massage vibrator, which is clamped to the side of the tank with an ordinary C-clamp. Care should be used that the clamp is not screwed up so tightly as to break the tank.—Thomas Allen, Flushing, N. Y. “Art” Glass as Showcards Squares of so-called “art” glass, opal, ruby, or other color, can be used as show- cards in stores and display windows. They are lettered in the usual manner with water colors or showcard colors; then, when a new card is needed, the paint can be washed off and the new lettering applied. Green or brown art glass, which is also called “cathedral”. glass, “pot metal,” and other names, held in a har- monizing frame, makes a very attractive sign which will save the continual expense of Bristol-board cards. 171 Heater Made from Auto Headlamp The photograph shows an electric heater that was made from a discarded The heating ele- automobile headlamp. ment from a standard heater was bought from an electrical- supply’ store, inserted in the position occupied by the bulb, and the electric wires led out through a porcelain tube placed in the hole previ- ously occupied by the lamp receptacle. A circular piece of copper screen in place of the headlamp lens prevents anything from coming into contact with the red- hot heating coil. The base of the heater is made from an old automobile-hub flange to which flat-iron supports are fastened, the latter being attached to the heater so that it can be tilted at practi- cally any angle—A. F. Willey, Jr., Grand Rapids, Mich. Forcing Obstruction from Drain Pipes Bathtub and similar drain pipes will be- come clogged at times, and it is frequently found that the ordinary suction cup will not dislodge the obstruction. The photo- graph shows a device which has been suc- cessfully used for opening up drain pipes with water pressure, and that, unless the stoppage is caused by a hairpin or similar article, usually clears the pipe. An ordinary rubber bathtub has a hole cut through its center, into which a piece of %-in. pipe is inserted and held by a nut on each side of the stop- per. A suitable length of garden hose is slipped over the end of the pipe and fas- tened securely with wire, or with a reg- ular hose clamp. In use, the rubber stopper is placed in the drain pipe, the hose is then attached to a faucet and the water turned on, forcing the obstructing matter through the pipe.—W. S. Standi- ford, Youngstown, Ohio. stopper

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POPULAR Milk Cart Made from Buggy Shafts Having a few cans of milk to take from the barn to the highway each day, a Michi- gan farmer devised a means of wheeling The Front Wheels and Shafts of an Old Buggy Made into a Truck for the Convenient Transportation of Milk from the Dairy to the Roadside them without spending any money. He simply took the front wheels of an old buggy, turned the shafts upside down and rested the cans on the crossbar, as the picture shows. Three milk cans can be carried at one time, and by placing a loose board or two across the. shafts, other articles can be carried as well. Polishing Bore of Gun Barrel When a shotgun or rifle has been neg- lected and allowed to go for some time without cleaning or oiling, the bore be- comes rusted, due to the action of atmos- pheric moisture and chemicals in the powder. Al- though a good cleaning with kerosene will partly re- move the worst of the incrustation, if the original high polish, which is con- ducive to good shooting, is desired, it may be obtained without much difficulty. Make an emery lap of the type shown in the drawing. A 14-in. steel rod is threaded at one end and fitted with two nuts, two hard-felt washers, and two smaller metal washers, while a handle is fitted to the opposite end. With the lap assembled as shown, use fine emery flour mixed with vaseline smeared on the felt washers, and clean out the spots with a | a. wee- “? | ae a Pp WASHERS t dl WOODEN HANDLE “ GUN BARREL— GUN BARREL MECHANICS reciprocating movement of the rod. “Fine” valve-grinding compound will also answer. If the felt washers are too loose-fitting, expand them slightly by screwing down the nuts until they fit rather snugly into the bore. After polishing off the spots, clean out the barrel and grease well. When the Light Fuse “Blows” Out When the fuse plug of the house-light- ing circuit “blows” out, there is usually an anxious wait until another is obtained. Any of the following sug- [, @. ———— gestions will © gee sone | permit the use (y ( of an old plug \ v during the in- ; terval. While Srowr-our effective, none of the methods are recom- mended or ad- vised for other than tempo- rary use, as the regular fuse is de- signed to blow when the circuit be- comes over- loaded, while the makeshifts are not. Should the wires become short-circuited the fuse will burn out, and unless the cause is found and removed, the new fuses will burn out as fast as they are put in. The first method consists in placing an ordinary copper cent in the socket and screwing in the old plug on top of it. The cent will fit the socket of either a fuse or a lamp, and is ever handy to com- plete a circuit. The second method is to split a thin rim or edge from the threaded brass rim on the fuse, with the blade of a knife, and bend this rim over the cen- ter contact, as shown. This is a practice often resorted to by electricians. The third method consists in folding a piece of tinfoil, placing it over the fuse plug across the center contact, and screwing the plug into the socket. : ae | \ } \ \ SOCKET BENT OVER CONTACT yee a ’ - a SLIVER OF BRASS FROM THREAD Adjustable Front for Brood Coop The proper housing of a hen and chicks is always a problem to the back-yard poultryman, who must avoid letting the youngsters out in the early morning be- fore any of the family are astir, in order

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POPULAR that a stray cat or dog may not get them. By using two strips of an old inner tube and the usual vertical slats, the openings in the front of the coop can be regulated to allow the chicks to pass through or restrain. them within. An old inner tube is cut lengthwise into strips about 1 in. wide. Two of these rubber strips are spaced to come at the top and bottom of the coop opening, and to them a row of slats or lath is tacked. The pro- jecting ends of the rubber strips are per- manently fastened to one side of the coop, and the ends on the opposite side are held by projecting nails. By stretching or re- leasing the rubber, the width of the open- ings between the slats can be regulated to confine or liberate the chicks as de- sired.—G. E. Hendrickson, Argyle, Wis. Repair for Broken Battery Post Owing to the vibration, a post was broken from an automobile storage bat- tery; this re- sulted in starting troubles, burnt- out lights, and other evils, until a temporary re- pair was effected in the manner shown. The halves of the ost were scraped bright, and a ein. hole was drilled into each; some lead filings were then placed between the rough faces, and a woodscrew was turned down through the sections until they were brought to- gether solidly. Soldering Holes in Tanks When a hole in a tank, can, or sheet- iron pipe is to be plugged by soldering, it will frequently be found difficult to make the solder bridge the opening. In an instance like this, an ordinary brass paper fastener may be pressed into service with satis- factory results. The prongs are pushed through the opening, cut to a suitable length, if necessary, and pressed down on each side, The hole is then soldered over, the fas- tener providing at once a means of bridg- ing the space and strengthening the repair. BRASS PAPER FASTENER MECHANICS 473 A Sailor Wind Vane A wooden sailor, who waves his arms and indicates the quarter of the wind, is something a little different from the conventional weather vane, or revolving wind wheel. The wooden figure is cut from %-in. white pine, or other soft wood,the arms being made sepa- rately and at- tached to the body by means of light iron wire passing through screweyes on the back of the body. The figure is supperted on a pole by an iron rod driven into the latter. After a large- diameter iron washer has been dropped over the vertical iron rod, it is inserted into screweyes on the back and leg of the sailor, so that the figure can revolve freely with each change of the wind.— Duncan M. Halliday, Chesley, Can. Mousetrap Prevents Theft of Auto An ordinary spring mousetrap, of the type that can be bought for a few cents, can be converted into an effective burglar alarm for pre- venting the theft of an automobile. Two wires, with spring clips attached to their outer ends, are at- tached to the trap in the manner illus- trated, and the trap is set in the usual man- ner. One of the clips is attached to the live terminal of the horn and the other is grounded to the frame to complete the circuit. The front wheels of the car are turned at an angle and the mousetrap is set in the mud pan so that the steering arm will touch the trigger when the steer- ing wheel is turned. When the trap is sprung the horn circuit is closed, and the horn sounds until the trap is removed. FASTENED TO LIVE TERMINAL ON HORN

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474 POPULAR A Motorcycle Bobsled Most motorcycle owners put their machines away when the snow begins to MECHANICS sled that uses the motorcycle power plant to drive it along the frozen surface. The front wheel and handlebars are removed from the machine, which is held vertically in a framework —_ | 7 | ne Minss| a aig SS 43 el ik Ye ee -. Se ~ x. * _ 3 * « “ O~iee . a ee ; e ads Lae = rs a -*, | “ ‘ ae = niga. 2 built as part of the sled body. The front fork is firmly fastened, and the rear wheel is placed be- tween two guideboards, so arranged as to prevent the walls of the tire from rubbing against the sides. An old tire was used on the single wheel, and ad- ditional traction ob- Instead of Storing the Motorcycle during the Cold Winter Months, It is Used, in This Case, to Drive a Bobsled: the Front Wheel and Handlebars are Removed, and the Machine is Held Upright in a Wooden Framework fly, and forgo their use during the winter months. However, the photograph shows how one enthusiast constructed a bob- tained by the use of a tire chain. The sled is steered by means of a steering wheel operating the front set of runners, which swivels on a pin at the center.—S. E. Gibbs, Colfax, Ia. Cork Extractor Made from Buttonhook An ordinary buttonhook, such as can be obtained from any shoe dealer, is easily converted into an effective imple- ment for re- moving thin corks and cardboard caps from bot- tles and tubes. In making the extractor, the hooked end of the button- hook may be either cut off or straight- ened out. A barbed point is then formed on the end, either by filing or grinding—John H. Schalek, Pittsburgh, Pa. Safety in the Use of Electric Lamps for Heating It is a quite common practice to use electric lamps for heating purposes, but the misuse of them is also very common, and may lead to serious consequences. It should be remembered that if condi- tions are such that the heat cannot be dissipated, a fire may be started. An Ordinary 25-watt electric lamp, burning under normal conditions, is en- tirely too hot to be put, with safety, into a rubber boot to dry it. If such a lamp at the end of an extension cord is placed in a bed to keep a person’s feet warm, and bedding is piled over it, there will be little chance for the heat to escape, and it will almost certainly char the bedding within a few hours—possibly set it on fire. When lamps are used for these or sim- ilar purposes, although such a misappli- cation is not recommended, the best and safest way is to employ bulbs of twice the voltage of the service current, for instance, a 220-volt lamp on a 110-volt circuit. These “oversize” lamps will gen- erally give sufficient heat without becom- ing dangerously hot. Another way to ac- complish the same result is to use two lamps in series, as by connecting two 110- volt lamps in series on a 110-volt circuit. Safety Catch for Box Camera Everyone who has carried a camera of the fixed-focus box type in a crowd, has been afraid that some one might accidentally rub against the trig- ger and expose the film so that the next picture taken on the same film would be worthless. By drilling a “%e-in. hole in the posi- tion indicated by the dotted lines and inserting a wire pin or small nail back of the trigger, the trigger cannot be moved and the lens uncovered until the pin is withdrawn.—-Chas. N. Shaw, Jr., Oxford, Ga.

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ANY amateur radio operators throughout the country are building radiophones, and more would doubtless do so, were it not for the fact that, while many articles have been written on the subject, in nearly all definite construc- tional detail is conspicuous by its absence, and, unless the amateur is thoroughly grounded in radio theory, he meets with little success. The telephone de- An Efficient Wireless Telephone By FRANK L. BRITTIN ing bulb or plugging in an electric iron. The rectifier tubes, shown in the upper right-hand corner of the full-page illus- tration, may be any of the various types on the market, but the transmitting tubes should be UV-202 tubes, the correct fila- ment voltage for which is 7% volts. The current for the transmitting-tube fila- ments is taken from the posts on the scribed in this article is simple and practical; the construction cost, which varies, of course, with lo- cality, is about $125, which is not much more than the cost of many good receiving sets. The range will vary with local conditions; with a good aerial and ground system, music and the voice have been transmitted from 100 to 200 miles, while under specially good conditions, an extreme range of 500 miles has been recorded with this instrument. The greatest hindrance to the EXTRA SWITCH! FOR KEY AND BUZZER | TO AS: 1NO-VOLT SUPPLY development of amateur radio- telephones has been that the builder was compelled to use a motor generator, an expensive unit, in order to get the necessary high- potential direct current. This objection AN , S Front View of Instrument Panel: The Tubes at the Top Are the Transmitting Tubes, Those at the Lower Left-Hand Side the Rectifying Tubes does not apply to the instrument herein described, however, as a new type of transformer is employed, being connected to a 110-volt alternating current source of supply as simply as screwing in a light- Back View of Panel: at the Left, the 200-Watt Continuous-Wave Transformer at the Right. The Dry Cells Are a Standard Four-Cell Unit The Inductance and Choke Coils are Seen transformer, marked “O.F.” (oscillation filaments), and the voltage is regulated by means of the heavy-duty rheostats, shown between the tubes. The rheostats are necessary because this winding of the transformer furnishes a potential of 12 volts instead of 74%. An a.-c. voltmeter can be used to advantage in this circuit, and adds to the ease of adjustment, although it is not absolutely necessary. The rectifier-tube filaments are lighted from the posts marked “R.F.” (rectifier filaments), and heavy-duty rheostats, as shown in the winding diagram, are rec- ommended for this circuit also (only one rheostat is shown in photo, as the instru- ment was originally built with but one). The posts marked “PRI.” are for the 110- volt a.-c. supply, and in this line, a 50- ohm rheostat, such as a _ 10-hp.-motor field rheostat, which can often be picked up cheaply, is of great benefit in tuning the entire circuit to best advantage. It is a good idea to have every part of the circuit variable, as far as possible. The post above and between the posts R.F. is 475

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marked +, this is for the positive lead of the d.-c. potential; the post for the negative lead, marked —, is found at the top, in the center of the transformer panel. This d.-c. current, which goes to the transmitting-tube plates, first passes through two 1'%-henry choke coils as shown, which serve to “smooth out” the current; a 2-mf. condenser is bridged across the line on each side of the choke coils. Each choke coil may be made by winding, on a soft-iron core % in. in diameter by 34% in. long, 1 lb. of No. 26 double cotton-covered magnet wire, or they may be purchased at a reasonable price. The 2-mf. condensers must be able to stand the high voltage; condensers specially built for this purpose are now generally available. The plates of the rec- tifying tubes are connected to the posts marked “P.” (plates), and when the un- marked post is connected to the ground circuit, the transformer wiring is complete. Following the 500-volt d.-c. line through the choke coils, the negative lead is con- nected to the ground; the positive lead goes to a No. 200 honeycomb coil, which prevents the high-frequency oscillations in the transmitting tubes from backing up into the transformer. From this coil the lead goes to a milliammeter, to the tube plates, then to the lower-switch lever on the inductance. The inductance consists of 40 turns of No. 12 hard-drawn copper wire, wound on a threaded bakelite tube, 6 in. in diameter and 8 in. long; this tube can be obtained threaded, ready to wind. The connections of the inductance taps to the upper and lower switches are shown clearly in the detail drawing; helix clips, instead of the switches, can be used here to advantage. The upper switch is connected to the aerial circuit, and in this circuit a condenser of .00l-mf. capacity is recommended; it should be able to stand a heavy voltage, and, while not absolutely necessary, is of great advan- tage in tuning. The hot-wire ammeter should read, by fractions, to one ampere, and be as sensitive as possible. The lead from the lower end of the inductance is taken to the lever of the three-point switch controlling the unit or bridging condenser. This may be homemade, and the units are of .0005, .001, and .002-mf. capacity, respectively. The dielectric in each unit is the best grade of India mica, 2-in. by 1%4-in. pieces being used, and copper-foil sheets, 134 in. by 11% in., are used between the mica sheets; the tabs on alternate sheets of foil are brought out at top and bottom, on the same side, being soldered together and connected as shown POPULAR MECHANICS 477 in the detail drawing, when the units are assembled. Bakelite panels, %6 by 154 by 31% in., are used to separate the units, and the assembly is supported by a metal strip, as shown. The .0005-mf. unit has five sheets of foil, the .00l-mf. unit seven sheets, and the .002-mf. unit 11 sheets. A bridging condenser, with a fan switch, can be used at this point if the builder does not wish to make his own. The grids of the transmitting tubes are connected in parallel; the variable con- denser in this circuit is of .0005-mf. ca- pacity, and should also be able to stand a high voltage; the lead from this con- denser goes to a helix clip on the induc- tance, to facilitate close tuning. The 10,000-ohm resistance, shown in the grid circuit, which is used to hold the grid neg- ative, is connected to one secondary ter- minal of the modulation transformer, the other secondary terminal being connected to the ground. The modulation trans- former and microphone transmitter are of standard make, and the primary is con- nected in series with a four-cell battery; this circuit, as well as the others, is oper- ated through the anticapacity switch, which, when thrown up, cuts in the trans- mitter, and when down, puts the receiver into operation. A key and buzzer can be used in this circuit instead of the trans- mitter, for c.-w. telegraphy. This com- pletes the circuit. The instrument panel is of bakelite, 54 by 18 by 24 in., mounted on a 34 by 8 by 24-in. wood base by means of metal shelf brackets, the panel being drilled for the instruments before screwing to the base. A shelf can be placed at the rear of the panel to hold the choke coils and con- densers, if desired. The entire “works” can be inclosed in a cabinet, but this makes it harder to get at if any adjust- ments are necessary. The wire used for the circuit may be No. 18 insulated fixture wire, wire smaller than this should not be used; a tinned-copper wire, now on the market, which can be covered, as the winding proceeds, by the so-called “spa- ghetti” tubing, is better still, as it makes a neater job and saves time. All connec- tions should be soldered but the circuit should be carefully studied before the connections are made permanent, and carefully checked before turning on the power. Put all the resistance in the circuit, then turn on the power. First regulate the rectifier-tube rheostats; the current flow from these tubes can be regulated much more easily if a d.-c. voltmeter, reading to 500 volts, is connected to the d.-c. out-

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47 8 POPULAR put. By means of this the rheostat scale on the panel can be graduated for the various voltages desired.. Calibrate the rheostat and graduate the MECHANICS be adjusted to find the oscillation point, no exact directions can be given for this. The unit-condenser switch is then ad- justed, and the circuit tuned to the maxi- TO ANTICAPACITY SWITCH INDUCTANCE, THREADED HOT-WIRE BAKELITE TUBE AMMETER 40 TURNS, NO.I2 ener 6" ores (COPPER WIRE 2x1z MICA~, GRID CLIP HERE ---* gxie" X24"HARD RUBBER ASSEMBLING CONDENSER UNITS 3x1} 3} BAKELITE PANELS ——~. - “ Gr UPPER-SWITCH LEVER OR BAKELITE “——_ 13 X15 COPPER 47° FOU “~3k 8x24 woop BASE REAR VIEW OF PANEL -----.000S MF. (TO TAPS -OO1 MF. -O005 MF. THREE- UNIT CONDENSER GROUND : TO TRANSMITTING-TUBE PLATES ‘~« 002 MF. GROUND ----*> = -oeee? t SCREWED TO BASE THREE-UNIT CONDENSER Details of Connections for Upper and Lower Switches of the Inductance; Method of Fastening Panel to Base, and Details of Construction of the Unit Condenser scales to, say, 250, 300, 400, and 500 volts; then the voltmeter may be discarded. Now adjust the rheostats of the transmitting tubes to the proper positions for regulat- ing the filament voltage (71% volts), by means of an a.-c. voltmeter, graduating these scales also. In tuning, after these adjustments are made, it will be found easier to adjust the entire circuit by means of the 50-ohm rheostat in the 110- volt a.-c. line. Next, place the upper and lower-switch levers of the inductance at about the posi- tion indicated by the dotted lines in the detail drawing, and place the grid clip in mum reading on the aerial ammeter; for the average circuit, this will be about 8 ampere, but may be more under favorable conditions. The reading on the milliam- meter should be low. The circuit is tuned by adjusting the variable grid condenser and the variable condenser in the aerial line, and also by changing the position of the switch lever on the unit condenser; by moving the switch on the 50-ohm rheostat carefully, the change of potential will often start the circuit oscillating. There is no specific method of reaching the point of oscilla- tion, as every instrument requires individ- position. As these points must, of course, ual treatment. MATERIAL LIST 1 bakelite panel, 5 by 18 by 24 in. 21 switch points. 4 pieces bakelite, 44 by 1% by 3% in. 1 .001-mf. variable condenser (optional). 23 sheets copper "foil, 1¥%4 _ 1% in. 1 .0005-mf. variable condenser. 26 sheets mica, 1% by 2 1 milliammeter, reading 0 to 100. 1 hardwood base, 4 by 8 by 24 in. 1 hot-wire — reading by fractions to 2 shelf brackets. 1 or 2 am 3 switch levers. 1 threaded bakelite tube, 6 in. in diameter, 1 standard 10,000-ohm resistance. 8 in. long. ; 5 heavy 7-ohm rheostats. 2 2-mf. fixed condensers for 1,000 volts d. c. 1 50-qghm rheostat. 2 1%-henry choke coils. 5 gooseneck tube sockets. 1 No. 200 honeycomb coil. 3 UV-202 transmitting tubes. 1 200-watt c.-w. transformer. 2 standard rectifier tubes. 1 standard modulation transformer. 1 anticapacity switch. 10 binding posts. 1 radiotelephone hand or panel transmitter. 4 nickelplated wood screws, 1% in. long. 4 dry cells. 8 nickelplated wood screws, 1 in. long.

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POPULAR MECHANICS . Emergency Oilstove Wicks During the war, the owner of an odd make of oilstove was unable to obtain wicks, as the manufacturers had closed their factories. In the emergency, a stove dealer suggested that heavy outing flan- nel might be used to advantage for mak- ing wicks. The strips of flannel were cut to the exact size of the original wicks, and the edges were brought together and sewed by “overhanding,” so that there would be no lap at the joint. Although these wicks did not last as long as the regular ones, it was at least possible to keep the stove in use.—Mrs. James Dore- mus, Passaic, N. J.

Releasing Hook from Fish’s Mouth It is often quite difficult to take the hook from a fish’s mouth, because the teeth or scales of the fish make the undertaking dis- agreeable, if not one of possible in- jury. In such cases a simple tool like the one shown in the drawing will be of great assist- ance. Obtain a piece of corset steel, or clock spring, about 8 in. long, and grind the ends round. Soften the ends in a flame, and bend them back so as to form hooks, then reharden the steel by dipping it, still heated, in water. Bend the steel into the shape shown, so that the ends will be about 4 in. apart. When a hook is caught in the fish’s mouth, insert the ends of the tool in the mouth by pressing the ends together, then release them, and the tension of the steel spring will force the jaws apart so that the fisherman can get at the hook with both fingers—L. B. Robbins, Harwich, Massachusetts. SPRING ENDS SOFTENED AND BENT—

Old Propeller Used as Anchor Not having a regular anchor at hand, a motorboat owner picked up an old pro- peller, put a long bolt through the shaft hole, and tied it to the boat by a length of rope. By dropping this overboard, it is easy to anchor the boat, as the pro- peller blades catch in the bottom of the stream or lake as readily as the flukes of an anchor.—John Y. Beaty, Chicago, III.

479 Muting the Violin Three original ideas for muting a violin in the absence of a mute of the ordinary type, are shown in the drawing. Three ordinary wire paper clips, slipped over the upper edge of the bridge between the strings, are quite effective in soft- ening the instru- ment’stone. They SS cost next to noth- \ — ing and can be a , carried tucked << ¥— . POCKETKNIFE — away in the pocket. A pocket- knife may be used as shown, one of

the blades being ' ea opened and the 5 knife then closed _ —@=—=—4___ around the lower part of the bridge in such a manner that the weight of the knife is supported en- tirely by the bridge. The third example shows the application of an ordinary comb, which is slipped over the strings, and thus reduces the volume of sound.— Henry O’Connell, New Haven, Conn.

Stopping Noise in Demountable Rims Demountable rims often squeak in an annoying manner, in spite of efforts to tighten them by various means or to remedy the trouble by the application of oil. This noise often arises from the fact that the bolt heads pull in- — to the rim of the wheel so that the EZ lug fails to grip the steel rim tightly. An ef- fective method of ending the trouble

\ BOLT ee oO METAL STRIP is to take some pieces of rather heavy sheet metal, about the same width as the HOLE FOR lug, and bend them as shown in the drawing. A hole large enough to allow the strip to slip over the bolt is drilled or punched at one end. The strips are then placed over the offending lugs, which are screwed down in the usual manner with the metal strip projecting between the lug and rim. This will take up the play and usually eliminate the noise— G. W. Greene, Madison, Wis.

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489 Worm Gears for Toy Machinery Every youngster who owns a small bat- tery motor delights in rigging up hoists, mills, and all manner of “machinery” for BENT NAIL AS —. ee STAPLE a | FINISHED GEAR Two Fixtures are Shown for Cutting Small Worm Wheels; the First Is for Use by Hand and the Second with a Lathe. The Last Picture Shows How the Worm Drive is Connected the motor to drive. As these motors nec- essarily run at high speed, and have only a very small torque, or turning force, it is always necessary to have some sort of speed-reduction gear, usually a system of large and small pulleys carrying strings as belts. A better arrangement is to use worm gearing, and the fine thing about this is the fact that a speed reduction of 100 to 1 is just as easy to obtain or per- haps easier than a 10-to-1 reduction. And as the speed is much reduced, the turning force is greatly increased, so that a very small motor will, when provided with a worm-gear drive, operate mechanism it could not even turn by means of the strings running over small V-pulleys. In worm gearing the driving member or “worm” is nothing but a screw; a special kind of thread is used on large screws made for the purpose, but this is not at all necessary for small worms to drive toys—any-bolt or machine screw that has a good, full thread will do for the driving worm, provided that the proper gear, or worm wheel, to serve as the driven mem- ber can be obtained. The worm wheel must have a number of teeth equal to the POPULAR MECHANICS desired speed ratio, one with 50 teeth giving a reduction of 50 to 1, when used with an ordinary single-thread screw. The only special tool needed for cutting worm wheels is an ordinary machinists’ tap. It should be of some common size, such as 14-20, and the worm or screw must, of course, be of the same pitch, in this case, 20 threads to the inch. Two methods of cutting the worm wheel are illustrated. Fig. 1 shows a fix- ture that can be made of three wooden blocks nailed together. A screw for hold- ing the gear blank, a wire nail, and a large wire staple are the only other materials needed. Fig. 2 shows how the work is done in a lathe; any lathe having a cross- feed can be used. It may be remarked that although the shank of the wooden block may be held quite rigidly in the toolpost, some kind of bracing block will have to be wedged under the forward end of the block to prevent chattering. The blank for the worm wheel is merely a disk of sheet brass or soft iron, with a hole in the center. It can be turned out of the sheet, or filed, if no lathe is handy. The diameter need not be determined ac- curately, unless the speed reduction must be exactly as it is desired. The rule for determining the diameter of the worm wheel is to multiply the pitch (distance between teeth) by the number of teeth wanted, and take %e2 of the result. Thus, for a 100-tooth wheel to fit a 4-20 worm, the diameter would be 100 X %o X%, or 1 1342 in. In practice,the diameter should be somewhere near 15% in., the main thing being to get the disk as nearly round as possible. In the hand fixture, shown in Fig. 1, the feed is obtained by striking light blows on the heavy staple. The staple should at first be driven in just so far that the teeth of the tap scratch the edge of the blank. The tap is then re- volved with a bit brace or wrench; when it has made 100 revolutions the blank will be scratched clear around. As the turn- ing is continued, notice whether the tap teeth have worked into the scratches pre- viously made, or are cutting new ones. If the latter is the case, apply a little pres- sure with the hand, backward or forward, on the blank, as the turning is continued and the tap is fed in with an occasional blow on the staple, so that the teeth will revolve in the grooves previously cut, and not cut double-pitch. Figure 3 gives an idea as to how the motor is connected to drive the slow- speed shaft by means of the worm and wheel. There must be plenty of play be- tween the worm and gear, as the simple

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POPULAR teeth of this type will not work well if pressed tightly together. The worm in Fig. 3 is made by turning, or filing down, a screw or bolt having the proper thread, so that journals are formed on the ends; the thread is also filed off for the sake of appearance, except at the center, where it meshes with the gear. To Prevent Funnel from Tipping A simple method of preventing a fun- nel from tipping to one side and spilling the liquid being poured, consists in slip- ping an iron washer over the stem; if desired, the washer can be permanently attached by soldering. This arrangement will be found particularly useful when both hands are required for pouring, as, for example, when filling the fuel tank of an automobile. A Screwjack Gear Puller Wherever gears or wheels are to be re- moved from their shafts, considerable damage may be done if the work is not properly performed, and, as gear pullers are not always available, or have not a large enough re range for the Ee ) ad yy 2 work to be done, the re- pairman is often tempted to resort to drastic meth- ods to remove “= . : bal — —— s ae | >) cramp an obstinate i _@ gear. Ifa SS R_ j= screwjack and - a few pieces of flat iron are at hand, they can be made into a powerful puller, thus removing the necessity of hammering the gear, with the attendant possibility of damage. Two bars are shaped to fit around the top part of the jack standard, and drilled for clamping bolts; these bars should not be made from material lighter than 42 by 2-in. steel. Holes are also drilled through each end of the crossarm thus formed, to take the pins which hold the pulling hooks. The hooks are cut from ¥% by 14- in. stock, and are also drilled for the ad- justing pins. With the hooks holding the wheel to be removed, and the head of the jack against the shaft, it is only necessary to turn the screw to exert pressure suffi- cient to pull off the wheel. Where pos- sible, the hooks should pull against the gear hub. MECHANICS 481 Improvised Scraper for Hardwood Floors A combination of a roller skate, plane blade, and a heavy block of iron makes a serviceable and efficient scraper for re- BALL-BEARING ROLLER SKATE ry, LONG HANDLE U-BOLT —~__ - PLANE BLADE CAST-IRON HINGE —~_ A Scraper for Refinishing Hardwood Floors can be Made from a Roller Skate, an Iron Block, and a Plane Blade finishing hardwood floors. This impro- vised scraper was made by an amateur workman simply by clamping the cast- iron block to the top of the roller skate. The plane blade was fastened to the for- ward end of the block by a screw and washer, for which a hole was drilled and tapped in the block. A hinged handle was attached to the de- vice by bolting one leaf of the hinge under the U-shaped clamp, which also serves to hold the iron block to the roller skate. With the scraper shown, all the floors of a six-room house were resurfaced, the work being done with much more rapidity and ease than would have been possible by the hand-scraping method. The edge of the scraper blade should be beveled at an angle of about 30°, and the iron block should weigh about 30 or 40 lb. to get the best results. Cure for Slipping Fan Belts An automobile fan belt that is inclined to slip on the pulley, either because it is too loose or because the pulley is worn too smooth, can quickly be made to run true and take hold by lining it with ad- hesive tape the width of the belt. The adhesive tape is that used for bandages, and can be bought at any drug store.

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482 A Burglar Alarm That Shoots A burglar alarm that will fire blank cartridges, when operated by the entrance of an intruder, can easily be made at a go LS ——_—_—___—_- — SCREWEYES ~ | 7 { Ny Re i THREAD TO DOOR = An Ordinary Spring Rat Trap, Converted into a Bu-- glar Alarm, Shoots Blank Cartridges When the Door or Window to Which It is Connected is Opened cost of but a few cents, from an ordinary spring rat trap. To convert the trap into a burglar alarm, it is only necessary to drill one or two holes in the base, into which .22-caliber blank cartridges are in- serted, in such a manner that the spring of the trap will strike the rim of the car- tridges and fire them. A hole is drilled underneath the trigger arm, and a thread or wire attached to the arm for releasing the trap. The burglar alarm is mounted on a base in the manner shown, the base being screwed down to the floor or shelf. The alarm is connected to the door or window by means of a stout thread or string, so that the door or window cannot be opened without giving an alarm.—Van Allen Lyman, Aromas, Calif. Test for Water in Gasoline The low specific gravity of most of the gasoline on the market makes it impera- tive that some caution be observed to prevent water from entering the supply tank. Chamois skin is frequently used, but this is too expensive to permit its common employment and is seldom at hand in emergencies. Cotton cloth will serve the’ same purpose if several layers are placed within the funnel to act as a strainer when the tank is being filled. Cotton is a powerful absorbent of mois- ture, and will remove all the water from the gasoline up to its point of saturation. POPULAR MECHANICS Care must be taken to see that nothing but cotton material is used. A good test for determining the pres- ence of water in gasoline is made by dip- ping a cotton cloth into a pan of the liquid. If the cotton remains damp after the gasoline has evaporated, there is water present in sufficient quantity to cause trouble in operating a gas engine or stove, Preventing Wear on Copper Kettle Having had considerable trouble in sol- dering a copper teakettle, that was worn through in several places around the bot- tom edge, means were sought to prevent this wear. This object was accomplished by soldering a ring of 4g-in. copper wire around the bottom edge, thus preventing the bottom of the kettle from coming into actual contact with the stove, and pre- venting further wear—Chas. G. Eng- land, Washington, Pa. Mountain-Type Wagon Brake A form of wagon brake which is more or less familiar in mountainous parts of the country produces a powerful pressure against the circumference of the wheels, and the speed of a wagon descending any grade which can be safely traveled is very nicely regulated. A cylindri- cal brake bar is suspended, parallel with the axles, from the un- derside of the wagon gear by short chains, as in the drawing. The ends of the brake bar, which is made from part of the trunk of a small tree, should project 6 to 8 in. be- yond the wheels on each side. A lever is inserted into the brake bar at one end so that the brake can be operated by the driver. When braking the vehicle, a for- ward pull on the lever brings the bar back against the wheels, and the amount of friction is controlled by the pressure ° exerted on the lever. When not in use, the brake hangs from the wagon gear out of contact with the wheels.—Louis Schneider, Clinton, Mo.

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How to Make an Inlaid Checkerboard By EDWIN M. LOVE te the checkerboard design illustrated, each square is a miniature checker- board in itself, composed of 64 light and dark squares. For the dark squares, 16 strips each of ebony and mahogany, %e6 by % by 17 in., are needed, and as many strips of maple and oak of the same size will be needed for the white squares, a total of 64 strips. Using alternate strips of light and dark- colored wood, eight strips are glued to- gether to make a laminated piece, 11% in. wide. From _ this seven strips of red oak, %e by 4% by 12% in., and 56 similar strips, 142 in. long. Paint the face of the board with glue and place in the angle formed by the strips at the edge, which should be at the lower left corner, one of the dark squares, with an ebony square in the corner, and the grain running parallel with the left edge of the board. Glue one of the short separator strips to the upper edge, and then place a light block in position, with the grain at right angles to piece, after it has been glued and both faces sanded, %e-in. sections are ; METHOD OF PREPARING LAMINATED STOCK MAPLE WHITE OAK — cut transversely, and eight such sec- tions glued together v CS PROJECTION % 4 “SS to form a square Ga METHOD OF ASSEMBLING BLOCKS MOVABLE BLOCK — that of the dark, and with the light maple square in the lower left corner, i] | | oF DETAIL OF GLUING JIG When the row of eight squares has been placed against the pine strip at the SEPARATING , STRIPS ~s BACKING BOARD of the board, using the gluing jig illus- trated for the pur- pose. The sections are cut %e¢ in. wide in a miter box. The strips are glued together so that light squares will come next to dark ones, the mahogany and ebony being used for the “black” squares, and the oak and maple for the “white” ones. All of the gluing operations should be done in a warm room and the stock should also be warmed. The wooden gluing jig should be made long enough to accommodate about eight squares at a time, each being separated from the other by a strip of paper. By rubbing the edges of the jig with paraffin, the glue will be prevented from sticking, and the blocks can easily be removed. For a backing board use a ¥%-in. pine board, 14% in. square. Nail and glue two Ye by 14-in. red-oak strips near two edges, to form a right angle, and also prepare An Inlaid Checkerboard, the Squares of Which Are Miniature Checkerboards Themselves, being Built Up of Light and Dark-Colored Woods left, glue one of the long separator strips to the inner edge of the row and start building up the next row. When all the blocks are assembled, inclose the two open sides with strips, and clamp them tightly until the glue sets. When the glue has dried thoroughly, trim the ends of the separator strips flush, and glue %e-in. strips around the remaining two sides. Cut off the edges of the backing board to leave a %%4-in. projection, and scrape and sand the sur- face smooth; wax it, or, if a higher gloss is desired, fill with a light paste filler and give three coats of varnish. @ Before using raveled-out wool for knit- ting, wind it in hanks, and place it in a steamer until thoroughly moistened. Then let it dry and wind into balls. The yarn will be straightened out and the color freshened. 483

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484 POPULAR Safety Spring-Hanger Bolts One job that will try the patience of the automobile repairman consists of lining up the eye ot a spring with the spring hanger in the chassis. The stiff springs are difficult to handle unless some means is provided for alining thetwo eyes. A simple jack for flex- ing the spring and lifting the weight of the car can be im- provised from a bolt and a short piece of pipe or tubing, as indicated in the drawing. These ma- terials are usually easily obtainable, and with a few of these jacks, much time can be saved in working the eye of the spring into the proper position for the insertion of the shackle bolt.—G. A. Luers, Wash- ington, D. C. AUTOMOBILE FRONT SPRING

A Simple Dimming Switch The drawing shows a very sensitive and simple dimming switch for use with an electric incandescent lamp, in locations where a dim light must be kept burning constantly. A hard-fiber, or bakelite, rod is turned down, as shown, to form a plunger, leaving enoughofthe original diameter to form a head, which isthen knurled. == == == =~ = = = == —— z SOCEILELSELPEEEDTOLLATLSA SPS POPIYLSSILLSPIS ID va ce

TERMINAL —— MERCURY

> N N N N N ; N ; Ny N NY Ny oe

MECHANICS the outside of the plunger, being firmly fastened at the bottom and led in at the top through another %e-in. hole parallel- ing the center one. At the bottom of the container, a small quantity of mercury is placed; as the container is screwed up- ward, the mercury rises in the annular space between plunger and container, so that the current flows through less of the resistance wire, thus increasing the cur- rent strength until full light is obtained. Screwing the container downward, of course, reverses this process. This type of switch has been successfully used on small motors and baking ovens, in addition to lamps.—W. Burr Bennett, Honesdale, Pennsylvania,

Combined Spring Spreader and Tire Remover A tool that serves equally well for spreading the leaves of automobile springs for the appli- cation of lu- bricant, or for removing a tire when the beads have rusted to the rim, is shown in the draw- ing. The tool can be forged on the anvil, from parts of old wagon tires, in less than an hour. A shoul- dered rivet is permanently fastened to the curved part, as illus- trated, and curved slots that fit around the shoulder of the rivet are provided in each end of the lever handle, but on op- posite sides. The span of the tool is somewhat different for the two uses, and for that reason the blade ends are rot quite duplicates, the difference being in the distance from the pivot hole to the end of the blade. The hook portion of the tool is simple enough to understand without explanation, while the only de- tail of the handle that need be further explained is that the end used for tires should be blunt, the opposite end being sharpened for easy insertion between the spring leaves. The blade can be removed from the device and used as an ordinary tire tool for pulling the bead over the rim.

BLUNT END SHARP END FOR TIRES FOR SPRINGS

\

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a i i POPULAR Spring Prevents Breaking of Fishline The big one that got away” would, perhaps, have been landed, had the strain on the line been applied more easily when the fish struck the bait. However, as fish are not particularly considerate, the angler must provide a means for prevent- ing his line from breaking, and one that will materially assist in landing his game. his may be done by merely interposing a short length of small-diameter spiral spring of the proper tension between line and hook. The spring will absorb a con- siderable portion of the strain on the line caused by the vicious lunging of cer- tain varieties of game fish.—O. S. Billings, Ruskin, Fla. A Jumping-Frog Toy \n entertaining little toy can be made from the wishbone of a fowl after it has been well cleaned and freed from flesh. lake a piece of strong, thin string and double it, be | ing it securely | to opposite | ' sides of the wishbone about 1 in. from the ends, as in the draw- ing. Cuta strip of wood a little shorter than the bone, and make a circular notch about 1% in. from one end. Push the stick through the doubled string for about half its length, twist the string tightly by means of the stick, then pull the stick through until the notch is reached. From a piece of paper or thin cardboard cut out the outline of a frog, paint it to resemble the animal as nearly as possible, and paste this to one side of the wishbone. The only thing now rgquired is a piece ~f shoemaker’s wax, which is placed on the underside of the bone, just where “ie free end of the stick will rest. When it is desired to make the frog jump, push the stick down and press the end into the wax. Place the frog on the table, and after a short while the toy will, all of a sudden, make a very lifelike leap as the end of the stick pulls away from the wax.—S. Leonard Bastin, Bourne- mouth, Eng. MECHANICS 485 The “X-Ray” Pack of Cards This trick is a “mind-reading” stunt vhich is worked on a new principle, and is very puzzling. A full pack of cards is shown and half of them are handed out, the other half being kept by the pertormer. A spectator is asked to select any card from those he holds, and in sert it in the pack held by the performer, while the lat- ters eyes are closed or his ’ head is turned. Without manipulating the pack in any way, the performer places it against his forehead and _ instantly names the card chosen by the spectator. rhe cards held by the performer are prepared for the trick by cutting a slot ¥% in. wide and 1 in. long in one corner of 25 cards, with the sharp point of a penknife, in such a manner that all the slots coin- cide. In presenting the trick the per- former keeps all the prepared cards, and also one card which has no slot, the lat- ter being kept on top of the pack so that the slots cannot be seen by the spectators. The performer's thumb is held over the slots when the bottom of the pack is shown. A spectator is asked to insert a card face down into the cards the per- former holds in his hand. When this is done the thumb is lifted from the slot as the cards are raised to the forehead, when the performer can look through the pack and see the index on the card the spec- tator has selected. After the forehead “stall,” the performer announces the card selected. The trick is repeated by “fanning” out the cards and extracting the card named. SLOT | Corked Bottle Used as Float A simple and effective substitute for a wooden float, which becomes water logged after continued use, for water tanks and similar purposes, can be made from old bottles. The bottle is stoppered with a tight-fitting cork, which is made leak-proof with sealing wax. The bottle can be fastened to the end of a float arm by means of metal clamps

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486 POPULAR Artistic Lamps Made from Vases and Drain Tile There are few household that create an atmosphere of furnishings hominess he aT Ye = an 1 2. a y . VASE 4 RED TILE CROWFOOT WOODEN BASE Attractive Table Lamps That can be Made from Such a Humble Article as the Ordinary Brick-Red Farm Drain Tile, or from Vases of Any Size and Form and furnish cheerfulness to the whole family more completely than lamps which harmonize with their surroundings. The common brick-red drain tile can be elevated to a position of beauty by using it as a part of a lamp of the type shown in the drawing. The tile itself can be decorated in any desired manner, as by painting some simple scene in oils against an enameled ground. The wooden base should have a diameter large enough to prevent the completed lamp from being easily upset. The electrical fittings, shown at the left, can be obtained from any dealer in such articles. The crow- foot should be screwed to the center of the wooden base in such a manner that the upright pipe will be in the exact cen- ter of the tile. When all parts have been assembled the space inside the tile is filled with cement. The vase lamp is practi- cally the same in construction, but be- cause the value of the vase is to be re- tained, no hole is drilled in its base, which makes it necessary to run the cord in over the edge, and down to the crowfoot. In order to make a lamp of this type stable, the vase is partly filled with dry sand.— Truman R. Hart, Ashtabula, Ohio. Soil Crusher Made from Mower Wheels A very useful implement for the farm, for breaking up hard lumps or clods on the surface, is a soil crusher made from old mowing-machine wheels, or wheels from a similar implement. If the maker of such a device does not possess a suffi- cient number of wheels, a few visits MECHANICS among his neighbors, or to the nearest junk man, will provide plentiful material. The construction of such a roller is quite simple and is done by merely mounting the wheels on a shaft of the proper length and diameter, with a thin washer between each pair of wheels. This shaft is mounted on a strong wooden framework of 4 by 4-in. lumber. A tongue is attached to the implement for hitching to the horses or tractor. The wheels re- volve freely on their stationary axle and consequently the proper differential effect is obtained so that corners can be turned without skidding. The wheels should be kept well lubricated to prevent undue wear on the shaft. Hook Pulls Straw from Stack Looking somewhat like the harpoon of the old-time whalers, the wooden hook shown in the drawing is used for pulling hay or straw from a stack, without wast- ing a con- siderable amount of it. The hook can be made from either wood or metal, so that it can be thrust easily into the stack. The barb is formed about 3 in. from the end; this catches the straw, and, when the hook is pulled out, a quantity of straw comes along with it. By using this method it is unnecessary to disturb the top that has been arranged to shed the rain. In case a metal hook is used, it can be fastened to a wooden handle, but a straight sap- ling will answer just as well, especially if there is a conveniently formed crotch near one end that can be utilized in forming the barb. HICKORY HOOK -. se a ‘ = { a 4 Flexible Liquid Court-Plaster A formula for making a flexible liquid court-plaster that can be painted over small bruises, cuts, and other unimportant wounds to keep them free of dirt, is made in the, proportion of 10 oz. of flexible col- lodion, which can be obtained at any drug store, 20 gr. of Canada balsam, and 10 drops of castor oil.

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| PRIZE OFFERS | EXAMINATIONS FOR INSTRUMENT MAKERS BY U. S. CIVIL SERVICE COMMISSION The | S. Civil Service Commission announces an open competitive examination for instrument makers. From this examination vacancies will be filled under the following bureaus and departments, at the yearly alaries indicated: Coast and Geodetic Survey, $1,400; office of the Secretary of Agriculture, $1,200; Bureau of Standards and Department of Commerce, $900 to $1,800; Weather Bureau, $1,300 and $1,440; super vising instrument maker, $1,620; and Naval Observa- tory, at $6.88 a day. Appointees whose services are tisfactory may be allowed the bonus granted by Congress of $20 a month. The examinations are open ill U. S. citizens who have reached their 20th, but not their 65th birthday. Applications will be receive by the commission at Washington, D. C., until the business-closing hour on March 31, 1922. Competitors ill not be required to report for examination at any place, but will be rated upon sworn statements of thet education and experience. Applicants must show that ‘ have completed the eighth grade of common ool. Partic position can be ulars of the experience required for each obtained from Washington. All desirous of competing should at once apply for form 1312, stating title of examination, to the Civil S ce Commission, Washington, D. C., or to the Secretary of the U. S. Civil Service Board in the ap- t locality. WORKMAN HONORED FOR WAR INVENTION BY THE AWARD OF A GOLD MEDAL “In recognition of an extraordinary engineering hievement with great public service,” was the nanimous expression of 2,000 members of the Ameri an Society of Mechanical Engineers, when at thei nnual mecting, Dec. 8, 1921, they awarded the gold medal of the society to Hjalmar C. Carlson, a sheet metal worker of Worcester, Mass. The engineering ichievement that won the award was described by the society as “his invention making possible the production of 30,000,000 drawn-steel booster casings, sed principally as a component of 75-millimeter higl explosive shells, and also extensively in gas shells and hombs, as an aid to victory in the World War.” These shells, which were used by the American army, were of French origin, and they had a_ peculiar “booster casing’ which gave trouble in American plants. Carlson’s invention more than removed this trouble, for it made pogsible the manufacture of the shells at a speed, and with an economy, that sur passed anything done in France. For the benefit of the layman, it may be stated that a booster casing is a casing for the primary detonating charge in a shell. TI i direct connection with the his is in fus PRIZES FOR AMERICAN-HISTORY ESSAYS OFFERED BY KNIGHTS OF COLUMBUS Fuller particulars are prizes tor now available regarding the American-history essays offered by the Knights of Columbus, as announced in our issue of November, 1921. The five prizes offered for the best tudies, based on research in primary sources, are as follows: a prize of $3,000 for professors or instructors in history, and other social sciences, in the colleges in the United States; a prize of $2,000 for specialists, not college teachers, on the same subjects; a prize of $1,000 for school superintendents and teachers in the United States, and another of the same amount for scholars and graduate students who have access to material in the universities, libraries, and archives of Mexico, Central and South America, and the Carib- bean Republics, dealing with the international relations of the Americas; and a prize of $500 for under graduates in United States colleges. Manuscripts must be in triplicate typewritten form, fully annotated as regards the authority for statements made, and must nelude a complete bibliography. Studies submitted m competition for prizes must have been prepared especially for this purpose, and must be mailed on or before May 31, 1922. Other particulars, including a nopsis of the topics and the periods ggested t be taken as theme for special investigation, may be btained m the Knights of Colum! Historical Commissic K. of ¢ Bldg., 199 M: etts Ave AUTOMOBILE CLUB OF MINNEAPOLIS AWARDS GOOD-ROADS TROPHY Each year the official pathfinder of t! Automobile Club of Minneapolis makes a tour in his car t some listant point in the state of Minnesot The counties through whicl he passes are then noti ed rhirty days later a part of about 75 cars be- onging to the club takes the ime tour, led by the path nde who keey about an hour ahead of the party, and leavés behind him a trail of confetti to show the route. Then ome another car, the pacemaker, which sets the speed shal travel. pilot car, at which the party With the party 1s a whose duty it is to guide them on the trail. The object is to decide which of the counties trav- ersed has made most improve- nts on 1¢ interval of ' days } tween the notifica « of the pathfinder and the tour of the party. This is judged by the pathfinder, the pace- maker, and the _ pilot, and to the county they select 1s awarded a handsome trophy, con- sisting of a winged bronze figure, be aring in one hand a scepter, ind beckoning with the other hand to the auto tourist. This figure stands upon a marble pedestal, making the trophy altogether 7 ft. high. Its cost was 1,200 dollars. BLIND WORLD-WAR VETERAN WRITES PRIZE-WINNING BOOK The prize offered by a New York publisher for the book of highest literary value written, during 1921, by a student of Columbia University, was won by David P. Sentner, a blind veteran of the World Var. The winner is studying journalism at the un ersity, under the auspices of the U. S. Veterans’ Sureau. The book, entitled ““Cobblestones,” is a col- lection of poems and essays. The blind veteran wrote all the manuscripts on a typewriter. GOOD EXAMPLE OF THE KIND OF CONTEST THAT BENEFITS A WHOLE COMMUNITY A contest of the kind that benefits all members of a community, whether contestants or not, is one that was recently conducted by the Fort Wayne, Ind., Chamber of Commerce, called “Better Yards Contest.” As its name implies, the object was to stimulate inter est in beautifying the yards of the community’s home Prizes were given for excellence in the care of lawn and sidewalks, in the growth of flowers, shrubs, tree and in the general outside appearance of the house The purpose of the contest was further promoted by the nature of the prizes, which were shrubs of a d 487

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488 POPULAR tinctive variety. These added to the yard and at the same time conferred the winner, to whom probably the as gratifying as the latter the upon was beauty of distinction former benefit BIG REWARDS OFFERED IN AUSTRALIA FOR DISCOVERIES OF PETROLEUM Up to the present very little oil has been discovered in Australia. In order to stimulate prospectors to greater activity in boring for oil, the government of the Commonwealth of Australia has offered a cash reward, equivalent to $243,000, for the discovery of petroleum oil in commercial quantities Australia, anywhere in This is defined as production, to the extent of 50,000 gal., with the oil still flowing freely. A sim ilar, separate rew ard of $48,600 has been offered by the state of New South Wales to the person or company who first produces 100,000 gal f petroleum within that state. It is now more than a year since these rewards were first offered, : ROOSEVELT JUNIOR MEMBERSHIPS OFFERED BY WOMAN'S MEMORIAL ASSOCIATION Theodore Roosevelt’s birthplace in | New Y is being restored by the Woman's Roosevelt rk* City Memorial Association, who, when the work is completed, propose to conduct therefrom a national educational move ment. In this connection they contemplate the founda- tion of a scholarship with annual prizes for the best essays on the life of Roosevelt In the meantime, the association will present a copy of that famous book, “Theodore Roosevelt’s Letters to His Children,” to each junior who obtains 25 junior memberships for the association. For the sum of only 25 cents, a junior receives full membership, and as a token thereof, a bronze medallion of Theodore Roosevelt mounted to be worn as a pin. This work is being carried out by the formation in schools of Roosevelt clubs. For par ticulars address: Woman’s Roosevelt Memorial Asso ciation, 1 East 57th St., New York City. MECHAN .ICS CONTESTS PREVIOUSLY ANNOUNCED Essays on Economics: Prizes, $1,000 and $500; announced June issue, 1921; closes Dec. 31; address, Dr. Wm. T. Foster, Newton 58, Mass. Medals, Diplomas, and Money Awards: Announced August issue, 1921; awards offered by the Franklin Institute. For Service to City of Philadelphia: Prize $10,000; announced September issue, 1921; awarded in spring or summer of 1922 by Edward Bok, former editor of The Ladics Home Journal. Research Thesis by a Woman: Prize $1,000; an- nounced October issue, 1921; closes Feb, 25, 1922; Idress, Dr. Lilian Welsh, Goucher College, Balti- more, Md. Model in Clay by Students of Chicago Art Insti- tute: Prizes, $i,900, $100, and $50; announced No- vember issue, 1921; closes April 15, 1922; address, Daily News Office, 15 N. Wells St., Chicago, IIl. One Million Francs for Best Motor: Announced anuary issue, 1922; closes June 1, 1923; address, Aero Club of France. Best Slogan Describing Razor: Prize $500; an- unced January issue, 1922; closes June 30; address Durham Duplex Razor Co., 190 Baldwin Ave., Jersey City, N. J. Hunting Stories, True or Fiction: Prizes, $1,000, $609, $400, $300, $250, $200, $150, and $100; an- nounced February issue, 1922: closes March 1; address: Contest Editor, Outers’-Recreation, 9 S. Clinton St., Chicago, Ill. Essays on Life of Roosevelt: On page 159 of our January, 1922, issue, have announced and for some time previously, we scholarship prizes offered by the Woman's Roosevelt Memorial Association, with the addition that the contest closed Dec. 31. This state- ment was premature, as a new announcement in this month’s Prize Offers makes clear. In answering prize offers please mention Popular Mechanics Magazine LATEST DEVELOPMENTS IN SCIENTIFIC RESEARCH By C. A. BRIGGS SATURN’S RINGS WILL BE DISPERSED BY ITS SATELLITES he rings of Saturn are unique in the sky and always commanded the interest of the astronomer. first question they raised was, “‘What are they?” The first mathematical investigation showed that they could not be solid but must consist of small particles. This was later verified by examining, through sensitive spec- troscopes, the sunlight reflected from them, and deter- mining that the inner edges moved faster than the outer, which could not be true if the rings were solid. The next question was, “How did they originate?” In attempting to get an idea of their source, astton omers and mathematicians have for years been trying to answer the preliminary question as to why the rings persist and why they are not broken up by the action of the moons of Saturn, and why they consist of a series. Furthermore, it has been determined re- cently that fine lines appear on some of the rings, suggesting subdivisions. A complicated mathematical study just concluded has developed some very curious facts about the mat ter. It appears that if the particles in any ring were all of equal size they would, under certain circum- stances, tend to leave that ring and mingle with those of the other rings, and the well-defined boundaries would tend to disappear. If there were a large num- ber of particles of all sizes ranging from very small ones up to a certain maximum value in the rings, the divisions of the ring would tend to become more extended and therefore more readily visible. It has also been discovered that the spacing of the rings is determined by the satellites, or moons, which revolve about the planet. Moreover, it is predicted that in tne course of time one of the satellites will cause the disappearance of the crépe, or innermost dusky, ring, and another moon will cause the other rings to be dispersed. The SOUNDS MEASURE FEEBLE ELECTRIC CURRENTS As science makes progress, there are many re- versals of practice, and what yesterday was used to obtain the best results is done differently today. For instance, the character and magnitude of sounds and musical notes have been determined by con- verting the sound waves into alternating currents and then measuring them by electrical instruments; but recently the tables have been turned, and very feeble alternating currents have been measured by con- verting them into corresponding sound waves which are measured on an acoustic device. The instrument developed for this work what similar to previous ones, but this particular arrangement is one in which remarkable _sensitive- ness is achieved. It is a well-known fact that a flat object, as a disk, tends to set itself at right angles to a stream of air or water in which it is held, and in the new device this is used as the actuating prin- ciple by suspending from a slender filament of quartz a very light mirror, which forms a disk in the neck connecting two resonating chambers. The feeble alternating currents to be measured are passed through a telephone receiver in the base of one of the resonators. The resulting sound sets up a minute pulsating draft of air in the connecting throat which causes the mirror to rotate to a degree that is a measure of the sound intensity and the current which produces it, and which is read by a suitably arranged telescope and scale, or by the movement of a spot of light. Such an instrument will probably have uses in scientific investigations, as, for telephone research, where it will serve to some ex- tent as an artificial ear, and in making psychological tests for measuring the sensitiveness of hearing of different persons under various circumstances is some- many instance, in