Popular Mechanics 1927-04: Vol 47 Iss 4

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‘Fete o£ tal Better Outdoor ‘ ay WRITTEN SO YOU CAN: UNDERSTAND IT REG. TRADE MARK GREAT BRITA: in ca : SEE PAGE 534

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— “i Write for “Saws in the Home” Let us send you ‘‘ Saws in the Home,”’ an in teresting folder on tools for the home—-or “‘Saw Sense,”’ a helpful book let on saws. FREE. Write toda ISIN ~“It Pays to Buy Better Saws” ERE are three popular ATKINS Saws worker or junior mechanic—there’s for carpenter, home one to suit your needs! No. 400 hand saw, preferred by master carpenters everywhere—the finest saw in the world. Extraordinary in quality, workmanship and finish. No. 53 hand saw, a lifetime saw for the millions of men who need a really good saw for horne use. Junior Mechanic hand saw, for the junior mechanic or Boy Scout. A handy saw for grown-ups, too. ATKINS Saws are made of “Silver Steel’’—the ATKINS exclusive steel that makes a saw hold its keen edge longer, and outlast two or three ‘“‘cheap”’ saws. ‘‘ Taper Grinding’’ makes ATKINS Saws cut faster, surer and easier. When you buy a saw, look for the ATKINS name on the blade. It guarantees you a better saw—one that will save you time, money and labor. E.C. ATKINS & CO., Est. 1857 426 S. Ills. St., Indianapolis, Ind. Leading Manufacturers of Saws for Every Use, Saw Tools, Saw Specialties and Machine Knives SAWS Here’ Nations on the $1000 : New Y pilots g post al, are in d uD pas etty The lifie puots, You 1ake naers rag preci dat ed k '| Bi is Aviatic $5 Rigger Flyers Taxi S We Aerial $2 Speci: $s! Aeria’ $5 Crop we Crop Be.

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_- ‘“ ye — POPULAR MECHANICS ADVERTISING SECTION An Actual Photo of One of Our Training Planes— A SWALLOW Learn to Fly by Sweeney System Here’s the great business of the future. The National Air Transport alone has invested $700,000 on the Kansas City air route. They are spending $1000 a day to operate an over-night service to New York City. pilots and ground mechanics. postal, government, or commercial work. Flyers are in demand, earning big money at fairs, taking up passengers, ete., $5 for a 10 minute flight is pretty fine pay! If You Want to Be a Pilot The student, if he wishes, goes into the air and qualifies as a pilot under safe and experienced pilots, with double controls for actual flying. You take all the actual flying necessary to make you a competent pilot. Now when you inderstand that two to seven hours is all the iverage man needs to learn expert flying you will preciate what this ample experience in the air under killed men will do for you. Aviation is no longer a mystery longer a hazard; no, it is a business growing greater more important. This has been wonderfully demon- strated in the successful flights over the North Pole. Big Money in Flying 4000 hours student Aviation Mechanics— $50-$125 Week flying without ma- Riggers—$50-$75 Week . Flyers $128-$228 Week terial damage. 150 Aerial Photo Pliot—$200- acre flying field. er Soocial Moosenger Service— Hangar and club Aerial Advertising -$225- jee Crop Dusting—$125-$200 Week Crop Survey—$125-$225 Week house. Seven in- structors. LEARN TO FLY BY SCHOOL of AVIATION 3606 SWEENEY BLDG, KANSAS CITY. Ambitious men are wanted as You can go into Sweeney Students as shown in this photo are trained by DOING. Thorough ground school work, under skilled instructors in the construction and repair of planes, recovering wings, tuning motor, etc.. learning everything about the mechanical work by actual practice. This fits you as an aviation mechanic. You can build your own plane and do anything required in aviation mechanics and construction and repairing when you have finished this work. You are thoroughly taught motors, etc., and work with thousands of dollars’ worth of new material, including all types of engines. Aviation is now playing in commercial activities. Progress is rapid. More men are needed every day. You can qualify as a mechanic, or an engineer, or repair man, or builder; five men on the ground are needed for one man in the air. , for full details of SEND NAME TODAY this aviation me- chanical course and photographs of planes and equipment actually used; also full information as to the commercial end of flying and opportunities for young men. No colored students accepted. SEND THIS NOW>-:--- = | EMORY J. SWEENEY, President | 3606 Sweeney Bidg., KANSAS CITY, MO. Please send me full information about your Aviation Course. | Name | Address

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New German Life-Saving Suit with Which with Two Short Blades Attached to the the Wearer Can Float on the Surface and Paddle Himself Around Hands—See Page 544

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eg E iN U. S. PATENT F Popular Mechanics Magazine WRITTEN SO YOU CAN UNDERSTAND [T APRIL, 1927 No. 4 ON THE THROTTLE & \N you imagine a train thundering against him, and again when he over the rails at a speed of eighty-five more than twenty-five mil n | an hour, approaching a red danger ler danger-signal 11 gnal and coming to a halt with the en- \ broken rail or open switch ahead will neer sitting motionless in his cab with- cause a brake application lf the engine ut attempting to stop the train? man does not comply with al nal i You wouldn’t believe it possible, but cations and speed regulations, the brake the Philadelphia and Reading railroad will bring the train to a stop. Any time tve such a demonstration recently of its the svstem or equipment fails, the train new train-control system, by which it is will be brought to a halt. hoped to make railway service practically A device, inclosed in a steel box and tool-proof. attached to the locomotive, is operated The system enforces obedience to sig- by an electrical current flowing through nals and compliance with speed regula- the rails, which are divided into sections tions. It applies the brakes automatically, or blocks, each 4,500 feet long. Contact if the engineer exceeds eighty-five miles is made by receivers suspended from the an hour, or when he goes above forty front of the locomotive, six inches above miles an hour, when caution signals are the rails, by induction The electricit \

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530 POPULAR MECHANICS travels to the equipment case, contain- ing relays, radio-amplifying tubes, where it is stepped up to high voltage and car- ried to the braking system. This train control also provides the en- gineer with a continuous, visible indicator in the cab, from which to determine at all times what speed he mayrun. Any changes in the condition of the track ahead of him are instantly registered on his cab indi- cator in sufficient time to enable him to increase or decrease his speed. when the indicator shows an “H” (high speed), he may run at eighty-five miles an hour; when it shows an “M” (medium speed), he may run at forty miles an hour and when “L” (low speed) appears, he must keep his speed within twenty-five miles an hour. If something unforeseen happens ahead of the train, instant warn- ing is given and the brakes will be auto- matically applied. The train-control system is operated in conjunction with automatic block signaling, thus reg- ulating the speed of the train to con- form with signal indications. So long as the engineer complies with the signals, the control of the train is left entirely in his hands, but should In short, . he fail to recognize them, the system t hold and either stops the train or redu its speed. In such cases it applies brakes but never releases them. After the brakes have been applied. : engineman has to release them by oy ating the acknowledging valve, to he is alert and in full possession oi faculties. The brakes hold for forty onds, before they can be released, 1 insuring that the train will be brou below the required speed limit. Such, then, is the svstem of the aut matic train control. Should the engi: man die or fall out of his cab, there. is danger of a wreck, killing or injuring ; sengers riding in a train so equipped. But a vast amount of work remains be done on the invention, before it can | used on all railroads. The present cost very close to $14,000 a mile. Then agai: there is the upkes of the track. Rai! road engineer however, are wor! ing day and nig! to improve the de vice and lower cost of maintenance Then will sucl catastrophes rear-end collisior , in fogs, derailment and other accident that take a toll ot human lives, be eliminated. SPEED GOVERNOR ON WHEEL > OF ENGINE AMPLIFYING SYSTEM OF AUTOMATIC TRAIN CONTROL

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POPULAR MECHANICS 531 ‘ROM AN ARMORED WARSHIP TO A FLORIDA HOTEL Once a Battleship and Now a Floating Hotel, the Experimental Vessel ‘“‘Amphritrite’’ as It Appears Re- modeled and Anchored on Lake Worth near Palm Beach, Florida Instead of being scrapped—the fate of 1ost old war vessels—the “Amphitrite,” an experimental battleship on which the sovernment spent several million dollars, is been converted into a floating hotel. lt is now anchored on Lake Worth near Beach, Fla., and has been comfort- bly arranged to Palm accommodate a large guests in equipped with every modern convenience. number of suites of rooms \ large roof garden, hotel connections to the mainland and numerous prome- nades are special features. BOOKS WITH COPPER LEAVES IN ODD COLLECTION Books with palm leaves and strips of copper for pages, others measuring a yard in length, some written on vellum and silk, “stitched, folded and rolled volumes as well as many other curious publications were exhibited recently at the Newberry library in Chicago. One of the most in- teresting specimens was bound between wooden endpieces and richly decorated in gold and lacquer on twelve thin copper sheets, about twice the size of an average automobile license plate. A Sanscrit manuscript was bound in elephant hide and others had been laboriously written silk. A Turkish written between 1600 and 1658, contained an account of the discovery of The character of the some of the on parchment or book, \merica workmanship on volumes indi- cated by the kind of ink used. religious was HOOD LINING PROTECTS MOTOR AND SAVES FINISH To reduce the likelihood of freezing in cold weather and to obtain greater efh ciency from the motor, a felt and isbestos lining material for the hood has lon the market. It also auto been place protects the paint by maintaining a more even tem- perature on the outer surface. The lining is so fashioned that the sides which cover the louvers can be removed quickly when driving in hot weather to prevent overheating.

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532 POPULAR MECHANICS HAZARDS IN DRIVING MONSTER SPEED AUTOMOBILE

28-GALLON REAR SOO HP GASOLINE TANK AERO ENGINE REAR ENGINE RADIATORS

MAIN CLUTCH DRIVE ENGINE REDUCT CHAIN COUPLING SHAFT BEVEL 3-SPEED FRONT SOOHP. GEAR BOX AERO ENGINE

FRONT ENGINE RADIATOR pipe aco es 5 /

EP Pye

F.W.BR BEVEL TRANSMISSION GEARS BRAKES

£ Rt ty aries, a wie ——_ er) Ae \ S*SERRALQAQAYL < “ 2 x - g LEB 2#¢¢ 77 Zn - SSAA an 4 s SSPE wAK “ ce Petal

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More Than Thirty Feet in Length, This Double-Engined, 1,000-Horsepower Racer Is Faster Than 200 Miles an Hour over the Sands at Daytona Beach The new racing automobile, built in England for Maj. H. O. D. Seagrave, to seek speed records on the sands of Day- tona beach, Fla., with twenty-five miles of hard-packed straightaway, has two motors developing 1,000 horsepower. The big car had to be brought to America to be let out to full speed because there was no course in England large enough on which to try it. While Maj. Seagrave only expected to make a 200-mile-an-hour record, the car was actually designed for a speed of 220 miles. The present inter- national record 170 miles an hour is held by an ishman, J. G. Parry Thomas, though several American drivers have made unofficial records higher than that. The new Seagrave car was built to better these unofficial marks. The builders encountered several unusual problems in constructing the giant, which has one engine over the front axle and one over the rear. They had to modify their body design considerably when they discovered that the car not only had the usual tendency to leave the ground and of Eng! Expected to Travel has been encountered wit! tested at Daytona, but tl the rear end wanted to fly higher faster than the front, with the result tl the car would have turned a somersault long before reaching full speed. Another problem was the effect of the wind pres sure if the car should be turned slight! out of a straight path while going 2) miles an hour. They found, in exper ments, that if the machine deviated little as ten degrees from a straight cours« flv. which other cars the enormous wind pressure would tur it around. Experts were consulted t determine how long it took the muscle to answer a signal from the brain, th: answer being four-tenths of a second. I: that time, at 200 miles an hour, the ca) would have traveled 120 feet, so it wa decided that it would be utterly impos sible for the driver to come out of a skid in the usual way if the car should go into one. The body of the unusual car in closes everything, even the wheels, to get away from the wind resistance the tires offer. The two engines, when fully out,

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Lg ae a a, onsume four gallons of gasoline a te. Seagraves, who is still in his has been famous abroad for years because of the frequent he has set up driving special rac- utomobiles. EATHER STRIP EASILY PUT ON ELIMINATES RATTLING eral advantages are claimed for an ved kind of weather strip in that it he applied by a novice, is thoroughly ited against temperatures and mois- bv a rubberized-fabric covering and res only a hammer and tacks for in- ition. Being flexible, it is simple to ist around corners, saving the trouble itering, sawing and waste, and it acts cushion to keep windows and door rattling. It also keeps out dust so it is suitable for use the year around. GAME OF HUMAN VOLLEY BALL LATEST OUTDOOR SPORT Firemen and policemen, training for an >t letic festival in Los Angeles, intro- ced something new in sports when tossed a comrade back and forth in gorous version of volley ball. Life vere used on both sides of a mesh er like that used in tennis and, be- ‘ding amusement to spectators vers alike, the game gave excellent in the use of the nets, which are of saving lives at fires. Over the Mesh from One Life Net to the Other: a Game of Human Volley Ball in Progress at Los Angeles POPULAR MECHANICS 533 SOUND BOX PRODUCES SLEEP BY MONOTONOUS NOISE Based on the fact that a softly hum ming, monotonous sound often serves to Hum from the Ornamental Box on Table Produces a Soothing Effect to Induce Sleep induce sleep, a clockwork apparatus pat- ented by a German doctor produces the desired noise for about forty minutes after winding. In order not to awaken the person using it by an abrupt cessa tion of the sound, this gradually becomes weaker until it finally dies away rhe outfit is contained in a small ornamental box which can be placed near the subject UNIVERSES OF STARS FOUND IN DEPTHS OF SPACE Four hundred spiral groupings of stat ‘ ir be | ) H b mm obse 5,700 t ‘ one 7 ] ] e id thevaret indred million time bright as our sun, according to the istronomer. He ilso states that it has taken something like a million vears for their light to reach the viant telescope where they were pho tographed.

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534 POPULAR MECHANICS HARPOON GUN DEVELOPED FOR OCEAN FISHERMEN Old Army Carbine Converted into Harpoon Gun for Fishing; Close View of Dart and the Entire Outfit Fishing for tarpon, sailfish, shark, por- poise, swordfish and other deep-sea game with a rifle harpoon is the latest sport among owners of fast seagoing motor- boats. The harpooner, with practice, it is claimed, can hit a six-inch target at fifty feet, which makes it quite easy to approach within firing range of fish bask- ing near the surface. The basis of the harpoon outfit is the firing mechanism and stock of a Springfield .45-70-cali- ber cavalry carbine of the 1873 model, fitted with a special barrel, short and much heavier usual, with a clear rifled bore. The poon sticks are lengths of dowel one end of whicl into the barrel rests on the end blank cartridge, load with forty-five g . of black powder. the other end of stick, the: harpoon head is loosely fit It consists of a bronze spear with 1 barbs nearly an inch and a half acro Two fingers extending from the heed sli alongside the front sight and keep t! harpoon lined up until it is shot \ length of wire leader is fastened to t! shot line, of which two hanks, contain ing 300 feet of light line and 150 feet of heavy, come with the gun. In action the harpooner coils the line in a keg or bucket placed to leeward so that it will not bloy 1 back and become tangled with his legs

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POPULAR MECHANICS 535 e running out. One is attached to the - leader and the other keg buoy, which can ossed overboard after ine runs out to mark position of the fish. e gun is provided with idjustable elevated sight to enable the ner to offset the nward pull of the line. rALKING MOVIES BY INVISIBLE LIGHT ‘’romise of further use he invisible rays of the ctrum is seen as the 1 ult of experiments in ploying them to trans If sounds and to project ition pictures. A physics fessor at the Massa 1setts institute of tech- logy recently showed it the invisible rays ld be harnessed to the es. The pictures were ible until thev sprang — Copyright, Herbert Photo ssighton a fluorescent Where Electricity Leaps a Mountain Canyon; Conduit over Stream in th> 1> French Alps More Economical than Cable Span reen. From the success + is experiment, it has been suggeste ted BRIDGE FOR ELECTRICITY SPANS automobile headlights could project WIDE MOUNTAIN CHASM t invisible ravs and yet expose aut idges, fences and other objects at night Electric current is supplied to a num they were covered with a substance ber of towns in the French Alps throug! would have a luminous reaction i. conduit that at one place in its course er the influence of the rays issumes the form of a unique bridge icross a deep mountain canyon. Con tructing the duct required col ( engineering skill, but the bi e p ived the expense o ir Lic would have beet equire in leading t ne do Lup the ot the chasi ARTESIAN WELLS HEAT HOMES AND PROTECT CROPS Ranchers near Reno, Nev., are utilizing natural hot water, found in drilling to depths of 100 to 120 feet, for heating thei homes and for irrigating to help protect various produce from frosts. The water eis has a temperature of about 200 degrees Dr. Donald Cc Stockbarger with Part of His Apparatus Fahr heit ; : . } for Projecting Movies and Sound by Invisible Rays threnheit and appears abundant

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536 POPULAR MECHANICS Samuel M. Greer, Left, and John W. O’Leary, President of the U. S. Cham- ber of Commerce, with Map of Phone Lines NET OF LONG-DISTANCE PHONES LINKS ENTIRE COUNTRY The widespread use of the telephone in this country is emphasized not only by the number of instruments in service but by the special long-distance lines which have been installed to speed communica- tion. With the completion, a few weeks ago, of the line linking Seattle, Wash., with the system, any the country hardly large section of is now isolated from long- distance service, as may be seen from the accompanying map. WAVES AND SUN HARNESSED TO LIGHT BUOYS Thousands of dollars are saved yearly by means of the so-called sun valve which automatically lights the lamps on gas buoys and in lighthouses for the protec- tion of many men for the task and is certain of operation. It is so adjusted that 1 darkness falls, the flow of shipping. It saves employing when acetvlene gas stored in a large container, is increased. Daylight turns the gas nearly off so that An- other form of buoy utilizes the action of the waves to operate a turn water for it burns low during the bright hours. pump which in running a small turbine to supply electricity for illuminat- affords ing the light. Fog he or moaning buoys are so rigged to work w out the aid of man. C pressed air is furnis|! by means of a pump -; tuated by the waves. | only attention requir is an occasional oiling lightship on the we coast of Scotland has crew. Its light without care and wl the vessel rolls, a b: but strikes. Dutch engines have also harnessed t sea to help strength: the dikes. Jetties are bu of reeds, running out ward from the emban| ments. These become covered wit gradua sand, owing to the actio of the waves, and by constructing succe sive jetties after others have become co ered, a strong reinforcement for the dil is soon laid down. TATTOO INSTEAD OF LIPSTICK GIVES PERMANENT EFFECT Tattooed lips, marked in “Cupid’s boy pattern of red, are reported to latest beauty fad in California, regardle be the of the pain that accompanies the oper: tion. The effect is permanent, saving r peated applications of the lipstick. Applying the Make-Up That Lasts; the Tattoo Needle Adapted as Substitute for Lipstick

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f a i Warm on Shore, Victor of the Long Battle with Tides and Chilling Currents; Young, as He Ap- peared a Few Moments After He Had Conquered the Cataiina Channel By JOHN ANSON FORD vear-old Canadian boy, swam the italina island channel to the California ainland, in fifteen hours, forty-seven inutes and thirty seconds, he made a that stands as one of the greatest nd most spectacular feats in the history athletics. There were 102 contestants and a first $25,000. At the start, Young, ho had ridden most of the distance from loronto to California on a motorcycle in ompany with a pal, was looked upon as merely one more of the big company of unprepared participants who were not ware of the terrific odds against them \ great many things have been cited responsible for the ad's astonishing victory, but all the worth- ile factors simmer down to just three ] ] nd these study by any Ws George Young, the seventeen- 1 ecord Trize of Canadian s being are vorthy of young person who may be dream winning honors in swimming—endurance speed, skill. All his life, Young has helped to sup port his ful, but resort district contributed a lot to his e1 7 he result was that Cat L111) widowed mother. The beaut: cold lakes of northern Ontari durance. channel, in spite of its comparativel) temperature, could not freeze him out Speed has been the second elet Young’s success. It saved the him in the cold cl el. | warm and it got him out of the several hours before many forecaste thought it possible to cross the cl His self-confidence was well illustrat: in a before-the-race talk he Capt. Harry Huff, of the tug “Mart! whicl had heen engaged George. “Meet me just outside

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538 POPULAR MECHANICS referring to the starting place had said in giving instructions. the boy “But how vill we know you from all the other swimmers?” Huff asked. “Pick out the man first to pass Bird Rock, 300 yards outside the cove,” will be me.” But and endurance would have won without amazing skill. George answered, “That speed not Some people have referred to George's stroke as “the Carlton.” Young and his trainer say this is hardly correct. They stated that had some helpful the young Australian swim- mer, Carlton, but that the stroke used was the straight George gotten ideas from American crawl. However, difference between Young’s execution of the American crawl and that of most swimmers, as between Paderewski’s and an performance on a piano. The | vreat there is as much there is amateur’s craw! is what George his vives speed. In non-technical terms, the crawl which Young used consists of alter- nate strokes with the right and left arm, while the legs keep up a continual flutter or kicking from the hips. The arm is brought out of the water, thrust forward and then swung downward and backward through the water until the hand is back near the hip. In the latter position the i hat bent to assist in rais- elbow is somew ing the arm out of the water and thrust- ing it forward again. The general direction of the motion o the feet, is at right angles to the plane o the body, the heels rising to within short distance of the surface of the water While the movement of the legs is almo continuous, the expert learns to so us the limbs that each benefits by a recur ring though short moment of rest, thu enabling the swimmer to keep up his ef forts for a period of time. Th: movement is largely from the hips, wit! a slight bend in the knees and the ankle relaxed. In fast swimming, such as a 220 yard dash or longer spurts, the legs wi ~ long give eight or more kicks to each strok: whereas in slower swimming, such as was necessary in the channel, the number o kicks per stroke may be reduced to a little as four. While endurance, speed and skill were the three essential features of success, co-ordination, Young’ balance and re laxation were the underlying principle on which his performancé rested. The three things mentioned first were possible only because the boy had learned periect co-ordination of the arm and leg move ments I have described, with his breat! ing. Many amateur swimmers instinctiy lv develop this timing of the breathin; Greasing-Up before the Swim; Enough Creams and Lubricants Were Used to Stock a Store as Contestants Sought a Protecting Covering from the Cold Waters

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POPULAR MECHANICS 539

ith the movement of eir limbs, yet many hers never get it, and are always out of reath or lack endurance. lance is also a vital ctor, for in that way no itt of the body is taxed induly and the energy xerted operates to the est advantage. In a ong-distance swim per- ips the art of relaxation of even greater impor- cance. Without it cramps re certain to develop. Mental poise accom- panies, or perhaps cre- ites, the capacity to re- ax. George says he never loubted his ability to reach the goal, though luring the age-long hours of the dark night, it must have seemed a hundred liles away. As the lad hlushingly stood before crowd and modestly tried to tell how he swam his way to victory, one could detect this poise that stood him in won- derful stead during the creat test. While the regulations prohibited giving the wimmers any physical <upport while in the wa- ter, attendants were al- lowed to supply the men and women in the race vith food. Some trainers devised long poles with tin pans attached to the outer ends. In these solid

and liquid foods were _—— ’ : ‘ i i tiie placed and held within Swimmer in Poses qos Various Positions of the Crawl Stroke Young reach of the human fishes. Others tied long-necked bottles to poles. These bottles, when filled with liquid nourishment, were allowed to float in front of the swimmers so that they could refresh themselves with a minimum of effort. Other devices included long rub- ber tubes through which liquid was trans- ferred by gravity. Chocolate and soups sed in His Victorious Channel Feat were the most popular forms of food. Not the. least interesting feature of the swim for the spectators was the lavish use of grease. Just before the start of the race, it was apparent that practically every contestant proposed to make his skin impervious to the salt water. Every make of cup grease was in evidence. Va-

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540 POPULAR MECHANICS rious cosmetics, in quantities sufficient to stock an ordinary parlor, from drug store or beauty were employed in giving coatings head to foot. In case, the grease was mixed with graphite. The race started and the great test, mental every shortly before noon much as physical, came when dusk set in. Swimming in the with sight and beautiful water about, is one thing, and plowing which was as daylight, cheering friends in h water menacingly black is quite another. A count of noses showed that after ten hours just ten con- testants remained in the “It was the last that hit trainer. along in the dark wit iter. two hours and a half George the hardest,” said his whole hour in which he made only 105 yards, by actual measurement. An ebb tide kept us slip- ping back from the shore; break your heart. “T 1 - . . © ihere was a enough to Three times the boy hundred yards of the finish and every time the water swept him back. No one who was not was within a few with us in hard alone in the our little boat can ever know how that lad battled out there Chart of the Courses Followed by Different Swimmers and Inset Showing a Racer Being Fed from Boat; Note Sullivan’s Short Journey; a Few Weeks Later, He Swam the Channel dark in the cold Pacific. But the endu: ance, speed and skill of youth won, ar finally George thrust his tingling bo beyond the grip of the tide, confronted with great field of kelp, in which he four himself tangled before he realized the uation. Once more he summoned h strength and, pulling off the plunged forward in a final spurt tha brought his rocks of Point Vicente light. only to one more menace weer ] feet to the RADIO TO SEND NEWSPAPERS MARCONI PREDICTS That reproduction of entire newspaper pages will soon be flashed across the At lantic by wireless, is the opinion of Senat Marconi, who believes that “the wonder of radio are not yet by a long way full disclosed or even realized.” has beet Such progre sending handwriting messages, pictures and dia made in typewritten grams by wireless that the transmission of entire newspaper pages is but advance step, a logical according to the inventor a eg : PSRANT VICENTE LIGHT “= rae

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POPULAR HOUSE WITH NO FIRE PERIL TO HAVE STEEL FRAME ‘Fireproof throughout” is a common rase in describing the type of construc- on in various kinds of buildings, but ery insurance company knows that the ord “fireproof” is generally used in a elative sensé and costly blazes occur al- ost every day in structures that were ipposed to be immune from such dam- e. However, a two-story, seven-room elling in Detroit, Mich., is said to de- the 100-per-cent fireproof stamp, it has floors of an asbestos composi- n laid on concrete supported by steel erTve ists, the walls are of steel-frame units nnected with insulating material and etal lath on both sides. A three-coat the outside ills, while the interior is finished in hard metal lath, with a dead-air Windows have steel sash, steel trusses and AC a eee es ‘le: d ‘ baseboards nh cement tile; aoors, trim, Daseboards, iterproofed stucco covers ister on pace between. e roof is of covered icture moldings and chair rail are steel, walnut; the stair tringers and risers are of steel, also enam- the treads ortar on metal lath topped with a com- osition flooring. The builder asserts that he dwelling cost no more than any frame tructure of good materials and ianship built on the same plan. nameled to represent finished, and are cement work- HITCH PERMITS TOWING AUTOS AT HIGH SPEED Easily attached to the service car, an djustable hitch insures greater safety in towing automobiles, as it prevents colli- ons between the disabled vehicle and the ne ahead, and keeps the trailer in line nd in the proper position on the street. he hitch consists chiefly of a V-shaped ar of two telescoping members, hv hooks to brack- ts which are bolted to the rear f the service car. \ clamp, attached to a ball-and- socket joint at the end of the bar, ‘an be connected to the front or back of that A triangle hitch is also furnished for use with a crane. secured the car is to be towed. MECHANICS 541 Stationary Running in the Training Tread- mill; Pugilist Taking Road Work in the Gymnasium with the Canvas Roller Belt . to Push with Feet and Grips to Support Part of the Weight BOXERS TRAIN IN TREADMILL TO DEVELOP BREATHING Road work is considered important in the pugilist’s training, as it develops tl lungs and leg muscles and cultivates en durance. Outdoor practice is not alway possible because of the weather, so a su stitute has been found in a form of st: tionary running ona canvas belt on rollers. The apparatus is like a treadmill partly supporting himself by handles at the side. Trainers declare that prac the same results can be obtained irom t apparatus as from regular road exercise. @ Helium has been produced in quantities from hydrogen in Germany.

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542 POPULAR MECHANICS ART OF SWISS SNOW SCULPTOR RIVALS WORK IN MARBLE Along with other winter sports, the art ] of snow sculpture has become increasingly fects. Some noted such virulent sympton that they immediately brought them the doctor’s attention. He was interest: to note that virtually all of them were tl milk patients and apparently had imagine their ills. The sting of tl bee, at least when taker internally, appeared to | less potent than the wi to be sick. The size o the potions was increased gradually in order that more definite effect would be obtained. CHIPS FROM ITALY MAKE MARBLE Marble chips, too small to be used for ornamental purposes, are shipped to the United States fron Italian quarries, mixed Mammoth Surmounted by Dryad Figure, a Snow Creation by Visitors at Swiss with carefully prepare | Resort Where Winter Sculpture Is Popular popular at Arosa, a center of winter fun in Switzerland. Temperature and _ the texture of the snow are often well suited to the fashioning of beantiful models, as the accompanying illustration of a mammoth and dryad shows. The beauty of the sculpture is best observed at night when lights are thrown upon the models. SWALLOW BEE-STING POISON TO TEST ITS POWER Do the sting of the bee and the bite of t e spider | help cure rheumatism and other Seeking light on these and similar qu tions with regard to tl insects » cement and fashioned into slabs which closely resemble real marble. A realistic texture is obtained by using pigments. Plain slabs are cast on concrete tables, while those with irregula edges are made from plaster casts. When they have hardened, they are rubbed down vith sand of silica and then finished with a fine honing stone so that the surface will be smooth. A polish with emery dust gives the required gloss. This “manu factured marble” is widelv used for table tops, stairs, floors and walls. SPEAKING TUBE IN HOUSE DOOR HELPS PROTECT HOME ah por~soaons,a New c~ York physician has been performing ome interesting experiments wit fiftv college students who swallowed cap- ules containing ugar of milk, veg- etable matter or the poisons. The sub- jects were not told what they had taken oOo protect the home against intru sion, a speakin tube in the door gives the inmate o! the house oppor tunity to decide whether the voice of a person outside isfamiliar or not. It is easily installed, requires no batteries or other connec and were asked to report on the ef- Using the Door Tube, and Close View of the Attach- ment with Perforated Mouthpiece tions and is adapted to any kind of door.

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POPULAR MECHANICS si + nd AERIAL MAP MAKING WITH ELECTRIC CAMERA MAIN SWITCH SHOWS WHEM SHUTIER IS SET jTOTAL EXPOSURE INDICATOR i _ INDICATES INTERVALS BETWEEN EXPOSURES PLANE FOR EXPOSURE CAMERA CONTROLS ; 7 R POSITION OF CAMERA } "Iw AIRPLANE - WIND MOTOR ~#. ma; LECTRIC MOTOR INATE DRIVE . ot “Ste ‘ ———_ “>> ag 5 Pi ee hes i y, ~~ - ~ : ss >> | : > Ms os a , Be at > yy mm | Peon ; 2 «Ress 5 F) / ; Teta! ry. 7 Rst ne : | ; en : AO , : Gur ’ IVORINE FOR ANY SPECIAL N S. W. Clatworthy Aerial Map Making Is Made Easier with a New Electrical Camera Which Is Entirely Automatic and Phot graphs on the Film a Complete Record to Guide in Piecing I: Together

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544 POPULAR MECHANICS LIFE-SAVING SUIT IS BUILT LIKE DIVER’S DRESS A German Diver Jump- ing from a Bridge, Above, | Wearing a New-Type Life- Preserving Suit Which Makes It Impossible for the Wearer to Stay under the Surface; at the Right He Has Come to the Top, Opened the Small Win- dow in the Helmet, Fitted to His Hands a Couple of Short Paddles, Which He Had Carried at His Waist, and Is Paddling Himself Along to the Shore A life preserver Ww hich closely resembles a deep-sea diver’s outfit has been intro- duced in Germany. It includes a com- plete rubberized suit and a helmet of metal, fitted with a window in front of the face, so arranged that it can be opened by the wearer, or closed and made water-tight. In tests, the demonstrator jumped from a high bridge, the fall being great enough to send him several feet under the sur- face, but, because of the large amount of air the suit contains, its buoyancy was Close-Up of New Life- Saving Dress, with Hinged Window Open sufficient to send him to the surface al- most immediately. As soon as his head was above water, the diver opened the window to replenish the air supply, fitted short paddles to his wrists and hands, and began rowing himself backward to shore The inventor claims that in event of ship- wreck a wearer of the suit could remain afloat indefinitely, even in a storm, by keeping the window closed most of the time and only opening it at favorable moments to replenish the air supply.

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Av®RICA GETS GIANT TELESCOPE rO SEARCH FOR NEW STARS hrough a huge telescope that has been ipleted after many months of work, ronomers propose a ten-year search out the skies from an observatory in uth Africa for the purpose of measur- the known double stars and to hunt rnew ones. The lens for the instrument — is made in Pittsburgh and cost $25,000. will be mounted under an electrically erated fifty-foot dome, costing approxi- itely $30,000. NOVEL ELECTRIC POWER PLANT REQUIRES NO DYNAMO Direct current, sufficient to light a forty- room house, is said to have been produced y an electric plant,the parts of which cost nly $80 and which makes use of a sys- tem of thermocouples instead of a dynamo. [he apparatus is the invention of two eastern investigators, who are said to have discovered an alloy of cheap and abundant metals to make the operation and con- struction of .such generating units prac- tical. The principle of producing elec- tricity, by variation of temperature in two different metals, has been known for more than 100 years, but has not been widely idapted because of mechanical and other difficulties. The heat required is fur- nished by oil, gas or coal burned beneath i cvlinder containing the thermocouples. Electric Plant without Dynamo; Cabinet Containing Thermocouples Seen at Right, Switchboard at Left POPULAR MECHANICS 945 Demonstrating the Traffic Signal Which Has Moving Disk, Seen in Top Bracket TRAFFIC SIGN HAS MOVING DISK FOR STOP AND GO Lights are supplemented by a moving disk, on which the words “Stop” and “Go” are marked in red and black porcelain enamel, in a traffic sign that also has a bell. The revolving disk is timed to show the signs corresponding to the lights, and the interval is easily regulated according to the volume of traffic. At night, the disk is illuminated with a floodlight so that it can easily be seen at considerable distance. The signal may be operated automatically or by hand. FIND FIVE NEW KINDS OF FISH IN WESTERN OKLAHOMA Among five varieties of fish, discovered by members of the University of Okla homa’s zoological expedition in the west ern part of the state recently, and hereto fore unknown, was a third type of black bass. More than 180,000 specimens were gathered on the trip and are being clas- sified for a museum.

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Head of the Snake God, One of the Most Used Deco- rations in the Ancient Mayan City of Chichen-Itza I OWN in the southernmost part of Mexico, in the state of Yucatan, which raises the sisal for American-made harvester twine, a great race of people lived and died nearly a thousand years before Columbus discovered the new world. At their height, they boasted a civilization as great as the ancient Egyp- tians; they knew more about mathematics and astronomy than any ancient people, and their builders, stone carvers and artisans in precious metals and other craftsmen turned out work the equal of any produced under the Pharaohs. Yet they died and their cities and mar- velous temples fell into ruins. Their civ- ilization was lost mainly ‘because they could not cope with the high cost of liv- ing, and their towns fell down largely for the reason that they had never learned to build an arch to hold up the roofs. The high cost of living for the Mayas was due to the fact that they possessed no draft ani- mals to plow their fields, and the agri- cultural methods they used eventually produced a turf so thick and heavy that their plants could not pierce it. All the first Spaniards found were the decaying ruins of great stone cities, won- derful temples and enormous pyramids. 546 SS OTic For four hundred years « more, the ruins have be pawed over by soldie: priests, adventurers, an: later, trained and amatet archeologists. Now, hoy ever, they are not only t give up their last secret but one of them, whic! was once the Mecca « the Maya world, is to b reconstructed as nearly a may be to what it was it its prime. At Chichen-Itza, the holy city o! the Mayas, a party of American arch #ologists, representing the Carnegi: institution of Washington, has em barked on a ten-year reconstruction pro gram, under agreement with the Mexican government that all the art treasures found shall be preserved at the site as part of a Maya museum. Chichen-Itza won its fame because it was the possessor of the sacred well in which Maya maidens were sacrificed to Kukulcan, the god of rain. Not only were the living sacrifices hurled into the sacred well as mates for the god, but gold and jade ornaments, beautiful pottery, carved wood, in fact, every kind of pos- session that its owner held precious, were cast to the waters, as well as an occasion- al enemy warrior whose valor was con- sidered sufficient to make him an attrac tive present. The sacred well is a huge pit, about 180 feet across and 140 feet in depth, with sides that are nearly vertical, or even un dercut in places. Fed by underground streams, it maintains an almost comstant water level seventy feet below the ground, making the water seventy feet in depth. A stone causeway, reminiscent of the Via Sacra, or Sacred Way, of Rome, leads from the pool of the temple of Kukul- can, a quarter of a mile away. The road- way is thirty feet broad and at places was elevated twenty-five feet above the sur- rounding plain so that the religious pro- )

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’ “ , “— : rs 5 or xe rs <. aw es it

Courtesy the Carnegie Institution El Castillo, the Great Temple atop a Pyramid, from Which the Religious Processions Advanced to the Sacred ell, to Throw Maidens In as Sacrifices to the Rain God cessions moving down from the temple were visible to the thousands packed ilong the way. The great temple itself rises atop an enormous pyramid, 200 feet square at the hase and seventy-five to eighty feet high, the exact height being difficult to meas- ure because of the debris which time and marauding soldiers have piled about the base. The top of the pyramid was leveled off in a stone terrace, sixty feet square, upon which stands the temple. The pyramid construction is typical of all the Mayan buildings. The sides steeply at an angle of fifty degrees, being broken into terraces nine feet high, each terrace faced with cut and _ perfectly matched stones, fitted so well they re- quired no mortar. On each of the four sides a great stone stairway, not quite so steep, breaks the lines of the pyramid. All Mayan stairs are much steeper than we are accustomed to, with steps, making it almost impossible to climb them wearing modern shoes. The barefooted or sandaled Mava Indians did not need the breadth of stair step we do. rise very narrow Each of the flanked on either side with a stone balustrade carved to represent an enormous serpent, the sacred image of Kukulcan, the body flowing down the pyramid in graceful un- dulations and each fold marking one of the terrace lifts, while the huge head, with bared fangs, is raised at the foot to face the approaching The problem of the ancient Egyptians in moving the huge stones of the pyramids was no greater than the difficulties the Mayas met in carving and placing the huge sections of these serpents. The heads, which represent fabled feather have enormous open jaws, stairways is stone visitors. snakes, exposing the fangs and extended forked tongues, every all, with the exception of the tongue, being made from detail correctly carved, and a single piece of rock. Two more monolithic ser- pent heads guarded the main entrance to the temple, facing the distant sacred well They also served as door posts, dividing The foreshortened heads were the bases of the columns, enormous the entrance way into three sections. and the tails were wrought in-

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548 POPULAR MECHANICS ok al N SETS HERE ON APRIL 918 AND SEPTEMBER 2% NOX 21ST MARCH RO SEPTEMBER ME Poem conee as oo -_* ee EASTERN STELA to capitals as graceful as any creation on an ancient Grecian column. The triple- vaulted ceiling of the temple, composed of an enormous weight of carved rock, rested on immense beams hewn from wood of the sapote tree, a wood that is almost as hard and heavy as iron. The beams are elaborately carved. An enormous stone table, supported by curiously carved human figures, origi- nally stood in front of the main doorway, probably having been used in some sac- rificial rite. Curiously, the figures sup- porting the table and all the carved fig- ures in the temple, covering every column, are bearded—the only bearded figures found in the entire city, built as it was by a beardless race. Close examination, however, indicates that the figures were carved to represent covering masks rath- er than actual faces, and that it is the masks which carry the beards—a fact that only adds to their mystery. Mayan legends are crammed _ with stories of a race from beyond the sea, some of the stories indicating that the originals of the bearded figures may have come from the fabled lost continent of Atlantis, while others lead some authori- ties to believe they may tell of Norsemen who arrived by boat, blown across the ocean long before the time of Leif Eric- son, who is reputed to have reached New Four and a Half-Mile Sundial, Used by the Mayas at Copan to Check Their Calendar, and Diagram Explain- ing How It Worked England’s coast about the year 1000 A. D. Edward H. Thompson, an American who for more than thirty years owned the plantation which includes the ruined city, collected a vast store of wonderfully carved objects, pottery and other. relics from the ruins, and, as a climax to his work, dredged and explored the sacred well and brought up not only the bones of more than ninety unfortunate victims of religious sacrifice, but gold and jade and other objects, the metal of which alone would be worth several hundred thousand dollars if melted down. In “The City of the Sacred Well,” T. A. Willard, a friend of Thompson’s, tells how the arch- eologists recovered a vast quantity of the treasure with a bucket dredge, and finally donned diving suits and descended to the bottem of the seventy feet of water to search out every last object which it might hold. Nearly all the pottery, bowls, knives and other instruments and utensils had been broken before being thrown to the rain god, for the Mayas believed that all objects had a soul, and that it was necessary to “kill” them by breaking so that the soul of the utensil could accom- pany the sacrifice victim to the spirit world. One rare find, however, was a wonderfully carved golden _ sacrificial knife, which probably had been dropped into the pool by accident. There also

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POPULAR MECHANICS CASA _DEL TIGRES BALL a COURT Chichen-Itza’s Temples and Sacred Well during a Sacrifice, When the Most Beautiful Maidens Were Hurled into the Water to Be the Brides of the Rain God, as an Artist Reconstructs the Scene

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wn ot ~_— POPULAR MECHANICS has ever been found out side of Asia. Previou to that discovery, it wa assumed the jade ha been brought from Asia over the land bridg: that once existed at Ber ing Strait. Compariso: with the American jade however, may only deep en the riddle. It is their knowledg¢ of astronomy, mathe matics and building, that interests the explorers more than their orna ments and worship. One of the ruins of Chichen Itza, called the Round Tower or Snail Shell, is unique in that it is one of two buildings of May an architecture which were neither square nor oblong. The name snail shell comes from a cir cular inclosed stairway in the building. It is be- lieved the round tower was an astronomical ob- servatory, and observa- tions made from it show that it was possible to sight through opposite windows and observe From T. A. Willard’s “‘The City of the Sacred Well,’’ courtesy The Century Company stars at certain times rhe Vv rer venty The Final Rites of Sacrifice Were Performed in a Small Temple beside the when the were “Fs : Sacred Well were many beautiful “hul-ches,”. or throw- ing sticks, which served the Mayas in lieu of bows. The throwing stick had a handle with a crosspiece somewhat like a sword guard, except that it contained two holes, for the first and middle fingers. The handle fitted in the palm, with the fingers through the holes. The end was curved over, to hold the end of a short javelin, while the shank of the weapon came up inside the palm, ready to be re- leased when the hul-che was brought for- ward in the throw. The large number of jade ornaments recovered from the well add to the mys- tery of the Mayas, but it mav be partly solved by the recent discovery of jade in the Pacific northwest, the first time it degrees above the hori- zon. Another Maya city, the ruins of Copan, discovered some distance away in Yucatan, has revealed an immense sundial, four and a half miles across, formed by two pillars on hills to the east and west of the city. By sighting from the east to the west stela, or pillar, it was possible to fix the change of the seasons, for the sun set directly behind the western stela on April 9 and September 2. The base of the western pillar has a second depression in which the column formerly was placed, and in that position the sun would set behind it four days earlier in the spring and four days later in the fall, showing that at some period the Ma- yan calendar had been corrected by sim- ply moving the column. The April date

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POPULAR MECHANICS 551 was the Mayan New Year, or beginning of their agricultural year. Both stela bear series of carv- ings in which many dates have been de- ciphered, while in the valley there are numerous small pyr- amids, one of which was erected to mark the passage of each twenty vears. The Maya year contained 365 days, but as they had no leap year, it gradually fell behind at the rate of one day every four years. One of the stela bears a date series which is translated as April 5 of our vear 471 A. D., while the other bears a date of April 9, ten years later, with the added information that this date was “O Pop” or the Mayan New Year's day. This not only fixes the new year as beginning on the first day of the agricultural vear, but likewise indicates that the moving of the stela occurred in that ten-year period. The Mayas at Chichen-Itza had an enormous athletic court, almost big enough for a football field, in which they played a game that apparently was a cross Implements from T. A Well,”’ courtesy The Century Company Willard’s “The City of the Sacred Reconstruction by the Carnegie Institution, Above, S of Ruined Temples; Below, the Game Court with . Stone “‘Basket” and a Sacrificial Knife and Throw- ing Stick and Two big between tennis basketball. carved-stone rings on opposite sides of the court were used to cage the ball, but, as they were placed vertically and at right angles to the wall, the ball could be batted through them only when the player stood very lose to the wall, a fact that probably required the players to be equally skillful with either hand. At either end of the court there was a small temple with a portico almost Gre- cian in its style, and the back of one of these porticos curved outward to form a perfect sounding board, showing the Mayas knew something of acoustics. Was A whisper can be heard across the court. The main work of the Carnegie insti- tution expedition, under Prof. S. G. Mor- ley, is concentrated at present on the re- construction of the Court of a Thousand Columns, which takes its name from the vast number of columns in it. lready a great throne and many rooms have been uncovered and the walls restored as far

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552 POPULAR MECHANICS ( if Whether Mayan Sculpture Was of Local Origin or Shows Traces of Influence from Overseas, Is a Ques- tion Puzzling to Scientists as the ruined masonry can be fitted to- gether again. The Maya builders never learned to make an arch, so their only way of sup- porting a vaulted roof or a doorway too wide to take a capstone, lay in utilizing a corbel, a form of construction in which each successive layer projects. slightly past the one below it, until eventually the two sides meet. The corbel, how- ever, is not self-supporting, as is an arch with keystone, and as the Maya limestone is soft, it eventually gave way under the burden, which accounts for the complete collapse of so many of their buildings. SUBMARINE PHOTOS IN COLORS LATEST PICTURE TRIUMPH Dangers and difficulties were encoun- tered, but successfully mastered recently, in taking natural-color photographs under the sea off the Florida Keys. Ordinary autochrome plates would not register the moving life under the water, so it was found necessary to make the plates hyper- sensitive in order that exposures might be reduced to a twentieth of a second. Be- cause of the dampness and excessive heat, this work had to be done at five o’clock in the morning to prevent the emulsion on the plates from melting. But even the hypersensitive plates would not register at depths as much as fifteen feet owing to the reduced power of sunlight; conse quently it became necessary to construct a flashlight mechanism which could be op erated by the submerged photographer at the right moment. Three small pontoons were built to support a dry-cell battery, reflector and flashlight powder, and the ap- paratus was so arranged that the diver could handle it and set off the powder. But the assistants who kept pumping fresh air to the man below the surface had to keep close by, yet manage to maintain a safe distance from the powerful charge of flash powder. The camera used in making the pictures was inclosed in a brass case with a plain glass window in front of the lens. Focusing was done with the aid of a re- flecting mirror, so that the diver did not have to bend over his instrument, a feat which would have been almost impossible while in his suit and helmet. ELECTRIC HEATER KEEPS AIR CONSTANTLY IN MOTION Operated from an electric-light socket, a portable heater has 175 openings at the top, permitting the heat to pass through and up- ward, so that cir- culation of the air is maintained as long as the cur- rent is on. Tests are reported to have shown that this type of heater will heat a room in one- third of the time required by an ordinary reflector unit. It is not intended to heat the whole house but merely one room, such as an office, bathroom or nursery. ee, tiifptotatate

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POPULAR MECHANICS ‘erryboat with Tilting row for Service between yermany and Denmark; t Can Carry 1,000 Pas- ngers and the “Hinged Nose” Aids in Docking and in Handling Cargo FERRYBOAT HAS TILTING BOW TO SIMPLIFY LOADING Run by oil-burning motors, a ferryboat operating between Germany and Den- mark can carry 1,000 passengers. A spe- cial feature is the construction of the bow which tilts up for loading and un- loading cargo from the end. FOOD PROBLEM OF AQUARIUM IS A BIG ONE Some fish eat meat or insects, others thrive only on certain vegetables, and still others will consume practically any- thing edible. Preparing the food for the many species of fish that will be housed in the Shedd aqua- 553 “bugs,” vegetarian fishes have a fondness for lettuce and cracked corn, while many of the smaller ones eat condensed foods such as dry shrimps. Some need an occa- sional extra “dish” as a variation in the fare; hence it will be necessary to give them snails, angleworms, lobsters, frogs and house flies from time to time. The can- nibal fishes will be watched carefully to keep them from indulging their desires, and for others that consume living crea- tures only, many thousands of minnows and shiners will be kept on hand. The fishes will be fed three times a week. MODEL PLANE MADE TO ASCEND WITHOUT RUNNING START Further progress riumin Chicago, will require two special rooms equipped with refrigerators and other conven- iences, it is esti- mated, while vari- ous parts of the world will be drawn upon for the sup- plies. The seahorse, for instance, is par- in perpendicular fiving is said to have been made by a Hungarian in- ventor, who has de- vised a model plane tial to certain va- rieties of salt-water Model of Plane for Perpendicular Ascents and Land- ings; It Is the Work of a Hungarian Inventor that can ascend without a running start and descend straight down. If successful, this will eliminate the need of a wide landing field.

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954 POPULAR MECHANICS Spray Nozzle in Use, and the Vacuum Attachment for Cleaning Automobiles Inside AUTO SPRAY GUN AND VACUUM SIMPLIFY CLEANING For cleaning the automobile, inside or out, two simple attachments, intended to be used with the air-compressor outfit, have been devised to reduce labor and save time. One is a spray nozzle through which water is forced to clean all parts of the automobile, and the other is a vacuum- cleaning attachment with a large nozzle and a smaller one for reaching into crev- ices. Both are said to be adaptable to low-pressure systems. USING BOTH YOUR HANDS GIVES YOUR BRAIN A REST About seventeen out of every 100 babies born are naturally right-handed, three are left-handed and the rest are capable of using either hand with equal ease, it is said. Due to methods of training, by the time the infants are three years old, all except the three who were naturally left- handed will use the right hand for most tasks. It is said that there are more than 400 different kinds of work in which the equal use of both hands is an advan- tage and, by being able to interchange, a vorker affords his brain an opportunity to rest, to a degree, for the muscles of the left side of the body are controlled by the right side of the brain while the left sid controls the muscles on the right side oi the body. Several famous men have been almost equally efficient with either hand. Landseer, the artist, could paint two pic tures at one time, using both hands, Leon ardo da Vinci was equally accomplished as was Holbein, the portrait painter. Si: Oliver Lodge can use both hands wit! ease and a British surgeon was noted for the fact that he could employ either hand with equal skill in operations. TABLE AND TYPEWRITER CASE COMBINED IN ONE Increasing the usefulness of the port- able typewriter, a carrying case, devised by a southern school-teacher, is converted into a serviceable table when unfolded. Besides the typewriter, which is taken without its own case, the container has room for writing materials and a small dictionary. Extended, it provides a spread of thirty by twenty-six and one- half inches, and folded, occupies a space of seven by twelve and one-half by fifteen It weighs only eight and one- inches. Table Set Up, and Folded as Case to Carry the Port- able Typewriter half pounds. Special catches on the leg joints insure the rigidity of the table.

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POPULAR MECHANICS 555

Transforming Insect Bodies into Bits of aan elry of Varied Pattern and Color; Pieces and Mounting a Specimen; Wax Treat- ments Help Preserve the Insect Bodies After They Have Been Properly Prepared

Sample

MAKING JEWELRY OF INSECTS NOVEL FRENCH ART Thousands of butterflies and beetles are converted into brooches, necklaces, earrings and other articles of jewelry by French artisans who are said to be the most skillful in the world in this unique craft. The beetles are carefully sorted, dismembered and then reassembled and treated with wax, to make them suitable for mounting. Butterfly wings are cut into geometric patterns for mosaic de- signs, under glass. Sometimes the butter- flies are inserted whole between sheets of glass for decorating ash trays, etc. AIR-POCKET CAMPING CUSHION IS EASILY INFLATED Inflated mattresses and cushions, for camping and other purposes, are not new, but most of them present a bulging sur- face when blown up, require considerable pressure and are difficult to inflate with- out a pump. A recently introduced type of equipment of this kind is so constructed that there are a number of inner sections or air chambers, resulting in a tufted and dimpled surface, similar to that of a heavy comforter. The articles can be blown up with the lungs, the load is more evenly distributed, and they are said to be softer than the ordinary kind. Hot-water bottles are also made in this fashion. When < “g filled,

the content does not all run to the bottom, causing the bottle to assume a bulging or pear-shaped form, and the tufted bottle may be wrapped about the arm or other portion of the body. The outer side is covered with cloth, and re- pairs may be made with ordinary auto- mobile-tire patching materials.

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i Sue py] ON at xq TM 2 2 Jas +43 Ul see VW se 1 ’ ' ‘ s Aare 1 03 iT 1 3 a4 jO SOW pee N jo suo

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and, ps in size, oni the Hull Built into Being € e Quart . A + 7 v or u c ~ _ ) ~ 2 o v 4 | > v - +} “Sh Unlike'the Ill-Fated Insets Show the Promenade Deck and One of the Pull- nan Sections Which Can Be Made Up for Night Berths Sketch of a Section of the Proposed New Dirigibles, Showing How the Two Side Keels Will Be Utilized to Inclése the Promenade Decks Air Liners to Have Cabins in Keels Two Zeppelins Authorized by Congress Will Be Largest in World and Twice the Size of the Ill-Fated “Shenandoah” | ADICALLY different from airships heretofore built, two giant Zeppe- lins, plans for which have been com- pleted at the Goodyear-Zeppelin factory in \kron, not only will be twice the size of previous American-owned dirigibles, but will exceed by more than 1,000,000 cubic feet the pair of aerial giants being built by the British government. Congress has authorized the construction of two Zep- pelins of 6,500,000 cubic foot capacity each, whereas the new English ships will have but 5,000,000 cubic feet of space. Profiting by the destruction of the “Shenandoah,” and other lessons learned in the past, the plans call for an entirely new form of construction. Instead of a single keel running the length of the ship to tie together all the circular frames that form the hull, the new ships will have three triangular keels, greatly increasing their strength. The control cabin and passenger ac- commodations will be inclosed within the hull, as will be the engines. Heretofore the motors have been carried in small gondolas sticking out from the sides of the ship. The plans for the new craft call for inclosed engine rooms, driving the propellers by means of shafts and gears. The arrangement will permit tilt- ing the propellers through a ninety-de- grée angle to add their upward thrust to the lift_of the ship in taking off. The ships are to have two complete covers, one on the qutside of the ring frames and another on the inside, while within the latter will be the gas cells, so arranged that a shot through one or two, deflating them, will not interfere with the operation of the ship. Two sets of plans have been drawn, one for a purely military ship and the other for a passenger carrier that can be 557

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558 POPULAR MECHANICS readily converted for military use. The latter will have accommodations for 100 passengers, with smoking and dining rooms and even a promenade deck, from the glass windows of which the passengers can look upon the earth beneath. These ships will have a cruising range of 8,000 miles, or 6,000 miles at full speed of ninety miles an hour. At that speed it would be possible to leave New York Sat- urday morning and arrive in Lendon Mon- day morning, while the return trip, owing to the prevailing westerly winds, probably would take a day longer, or from Friday to Monday. down The authorization by congress of the two ships marks the progress in aviation since the “Shenandoah,” with less than a third their capacity, was built. It had the slim lines of the earlier Zeppelins, while the new ships, like the “Los Angeles,” will have greatly increased girth in proportion to length. The increase in girth gives greater strength, cutting down the extreme length which made it easy for a ship to break its back. Despite a capacity more than three times that of the earlier ship, the new craft will be but 100 feet longer, permitting them to be housed in the pres- ent Lakehurst hangar. Money to build a new helium-extraction plant has been asked for, to insure sufficient gas supplies by the time the ships go into commission. MOST AUTO ACCIDENTS OCCUR IN EARLY EVENING Between five and six o’clock in tl evening is the most dangerous hour fo: motor-car driving, according to a surve of more than 1,000 accidents by the N tional Automobile chamber of commerc: Apparently, increasing fatigue during t!] latter part of the day is an important fa tor in the situation, for though some oi the morning hours have a heavier traffi the afternoon and evening hours gene ally show a larger percentage of accident While Saturdays and Sundays show t! greatest number of fatalities, it is thought that these figures are likely to be mi leading and that these days are really no worse than others with respect to accidents if the increased volume of traf fic is taken into consideration. Sunda showed a fatality rate only twenty-three per cent greater than that of Monday. CARVED PROW ON WORK BOAT SHOWS BURMESE SKILL Carrying cargo in elegantly carved boats would be considered incongruous in this country, but it is done every day in Burma where wood-carving is one of the national arts. Many of the rice boats and other small craft have handsomely figured prows and other adornments. The Burmese have become world-famous as woodworkers and silversmiths. Fancy Enough for a Pageant but, in Reality, Only a Work Boat; Beautifully Carved Prow of a Burmese Craft That Plies Canals and Rivers of That Country of Original and Gorgeous Art

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POPULAR MECHANICS 559 Models Illustrating How a Cuban Inventor Proposes to Raise Sunken Ships; a Feature of the Plan Is That the Pontoons Can Be Assémbled in Groups According to the Size of the Craft PONTOONS FOR RAISING SHIPS TESTED WITH MODELS Ingenious pontoon models have been constructed by a Cuban inventor to dem- onstrate a system he has developed for raising sunken ships. In a test at Ha- vana, one of the pontoons is said to have lifted twenty-five times its own weight. Among advantages claimed for the plan are the lightness of the tanks and the ease with which they can be grouped and fastened together by frames for tackling large or small vessels. As in other pon- toon systems, use is made of compressed air to force the water out of the tanks after they have been submerged, to make them buoyant and so float the wreck, which is hoisted to the surface by means of hawsers passed underneath it. LIGHTNING STRIKING A VESSEL THROWS IT OFF COURSE Compasses were seriously affected on the motorship “Narragansett” not long ago when a bolt of lightning struck the vessel as it was cruising in the north At- lantic. The needles spun about rapidly, then settled down but,with marked devia- tions. One indicated a westerly course, another an eastern, the difference being as much as twenty-three degrees. To meet the unusual situation and regain the proper course, the officers had a platform erected above the wheelhouse sufficiently high so that the magnetic influences in- duced in the house by the lightning would not be communicated to the instruments placed on the elevation. WINDOW WASHER AND DRIER COMBINED IN ONE Window panes are washed, dried and polished all with one simple in- strument that has a rubber sponge on one side and a spe- cial squeegee on the other. It is not necessary to put the hands in water when using this tool, as it has a grip in the center for fastening a pole if needed. @In London, forty first-aid stations have been placed at busy traffic centers.

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560 MOVIE-FILM SPEED REGULATED BY ORCHESTRA LEADER So that the orchestra conductor may develop better effects, while interpreting the picture with a musical selection, a Giving the Orchestra Conductor Control of the Motion- Picture Film’s Speed; the New Regulator Box German inventor has devised a speed con- trol for the film, operated by the leader from the pit. With it, he can accelerate or retard the movement slightly, to ac- company the music more realistically, without destroying the general effect to the spectators. In many theaters where the music is an important part of the pro- gram, the film is given a trial run before it is shown to the public and, at this test, the orchestra leader and assistants calcu- late the exact time of different passages. FIND HUGE PETRIFIED FOREST IN TEXAS VALLEY Nearly 100 miles from the nearest rail- road, a petrified forest, said to surpass any previously known, has been discovered in an almost inaccessible valley of the Big Bend region of Texas. Few white per- sons have visited the locality, and the ground is covered with a thick layer of voleanic ashes and pumicestone, which partly hide some of the stone trunks and indicate that the forest is of great an- tiquity, for no volcanic disturbances have occurred in the region for hundreds of years. Some of the petrified trees, 100 to 150 POPULAR MECHANICS feet high, were found standing,and one that had fallen measured several hundred feet. From a distance, the upright trunks have the appearance of natural-rock columns. WATER SLAP BLACKS THE EYES OF RECORD HIGH DIVER A new peril of extremely high diving was brought forcibly home recently to a young Italian immigrant who tried to commit suicide by diving off the Manhat tan bridge in New York. With his body moving more than ninety feet a second at the end of the 142-foot drop, the slap of the water when he struck blackened both his eyes and sprained his wrist. After hitting the water he decided to live, so began to swim and was picked up by a tug. OIL BURNER THAT USES WATER REDUCES HEATING COST Greater economy, more heat and less likelihood of explosions are cited among the desirable features claimed for an oil burner that may be adapted to almost any size of furnace. Its distinguishing point is that it consumes a mixture of oil and water with the results suggested above, and the additional advantages that no carbon deposits | areformedand | odorous fumes are _ || eliminated. The apparatus is ar- ranged in such a | way that the small | particles of water become covered with a film of the oil while the hy- drogen and oxygen in the water are lib- erated and provide an additional supply of elements for combustion besides the air. With this installation, it is ‘said, special fire-box lining of brick or other materials is not necessary, and the burner can be throttled down to a sniall oil con- sumption so that heat may be maintained without waste of fuel. @Our Bureau of Information will an- swer all questions regarding articles ap- pearing in this magazine.

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POPULAR MECHANICS Inspecting the Cables nthe Incline Railroad up Mt. Lowe GUARDING LIVES OF MILLIONS UP “STAIRWAY TO HEAVEN” In the thirty-eight years that it has been in Operation, the incline railway up Mt. Lowe, Calif., has taken millions of per- sons to the summit and, in all that time, there not been one accident. The record is considered a noteworthy achieve- ment in safety practice, since the “Stair- way up to Heaven,” as it is called, in places has a sixty-two per cent grade. The cars has used are of a special type and are pulled to the top by an endless steel cable which is tested to a 100-ton capacity, but never loaded beyond a five-ton limit. The tracks rest on stringers framed to the ties to pre- vent creeping, and, as a further safeguard, each car is equipped with a larger sta- tionary cable work- 561 shows him the exact position of the cars during the trips. The pulling cable is re- placed every year and is inspected weekly. In this task, slowly down the center rail on a board applying the brakes with his feet that he not to walk. He can reach the cables on both sides. Chang- a skilled cable expert slides car, sO does have ing the huge line is an exacting task, as the speed of the machinery at the top of the incline must coincide exactly with that of the power reel taking in the old cable at the foot. SANDER ON HEAVY AUTO TRUCK PREVENTS SLIPPING German truck designers have gone to the railroads for one of their latest attach- ments, a sander ing through an automatic clutch to hold it in case of ac- cident. The hoist is run by a 100- horsepower electric motor and rate safetv controls are provided. The operator has before him a miniature model of the rail- way elabo- Sand-Distributing Nozzle system, which Ye as in Front of Rear Motor-Truck Wheels which distributes a supply of dry dust in front of the rear wheels to prevent skidding on slippery surfaces. Thear- rangement is similar to the equipment on a rail- sanding road locomotive The box holds a = generous supply Seen in Center Di-ectly and is easily refilled.

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562 POPULAR MECHANICS DEATH TRAPS OF PLANT WORLD WAR ON INSECTS Of recent years, scientists have been visioning a world freed of its disease-car- rying flies and mosquitoes, its gnats and crop-destroying bugs, and the thousands Drawings of the Sundew, Jack-in-the-Pulpit, Lady Slipper, Pitcher Plant and the Venus Fly Trap, Show- ing Their Honey-Filled Death Chambers and Dangerous Tentacles That Trap Unsuspecting Insects of other insects with which it is-burdened. Curiously enough, it is to the plant world that they have turned for relief instead of to the inventions of man. For nature, compensating for every evil, has created plants which need only be developed in sufficient numbers to destroy the insects. These plants are found all over the globe, and the United States possesses quite a few different species. Down in North Carolina, for instance, is a remarkable plant that preys upon insects. It is called the Venus fly trap. Although it usually . Me LM: sll did lata, ee is found on waste lands, it is one of th: most successful hunters of big game, i: proportion to its size, in the world. Flies worms, beetles and bugs of all descrip tions are trapped by it, after which the plant pro ceeds to devour its catch It consists of a reellik: stalk, surmounted by flower, and several broad bladed leaves at whose tips are the traps. Eac! trap is in the form of two lobes set at slightly les than a right angle. Along the outer edge of each lobe, giving it the appear- g ance of an inverted eyelash, is a row of small thorns. On the inside are three sen- sitive hairs which spring the trap at the slightest touch SHOE SOLES GLUED ON INSTEAD OF SEWING OR NAILING In rebuilding shoes, a process for glu- ing on the soles instead of sewing or nail- ing them has been developed with consid- erable success in foreign countries, and is said to be gaining in popularity here. The method in- volves the applica- tion of special ad- hesives and the aid of a powerful hy- Rene draulic press. One of the most effective presses provides a leather surface on which to set the shoe for gluing and when pres- sure is applied, the leather follows the con- tour of the old sole evenly, as the water insures even distribution of the force, and a perfectly fitting shoe is the result. VANISHING SHOW CASES GUARD PRICELESS GEMS Valued at $3,000,000, the great Regent diamond as well as many other precious jewels, is on display in a glass case at the Louvre, stared at by scores of visitors daily and apparently in a favorable posi- tion for’ anyone intending theft. But robbers, bent on pilfering the gem collec-

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POPULAR MECHANICS 563 n, would meet a surprise should they er the room at night, for it would be pty save for busts and vases weighing much as a burglar-proof safe. The vel cabinets are so arranged that they ippear into skillfully concealed vaults neath the floor, and the apparatus which ts and lowers the platforms is also hid- en and so complicated that only author- ed attendants, who know the suld possibly operate it. secret, CLOVER THAT PLANTS ITSELF TO AID FARMERS Government plant testers see consider- ble savings of time and expense for rmers in two kinds of self-perpetuating which have been under observa- on at the experiment station near Wash- ngton, D. C. On one, the bend and scratch the surface of the rround shortly after the pods have formed, so that the seeds are deposited under fa- orable growing conditions, unless the soil s too hard. The other kind perpetuates tself even after it has been ithin an inch of the ground. lover, stems lown mowed to PENCIL AND FLASHLIGHT IN ONE HAS MANY USES Resembling a fountain pen in appear- ince, a pencil has a small bulb lighted by a battery inside the holder. It is special- Drawings the Pencil and Its Typical Uses Showing Light, and ly adapted to use in a sick room and, as a light alone, is always ready- YEARLY SOOT FALL IN LONDON SIX TONS TO SQUARE MILE aa tte t dl), Soot Meter in Operation; Removing Bottle of Dirty ater for Analysis of Contents From measurements made with an in- teresting gauge at a London weather of- fice, experts estimate that about six tons of soot fall on every square mile of the city’s area in a year. The gauge consists chiefly of a funnel arrangement through which rain falls and is collected into bottles. Once a month, the con- tent of the bottles is subjected to a chem- ical analysis and this examination, the total amount of soot is computed water from LIZARD LIKE BEARDED DRAGON FOUND IN AUSTRALIA There are some 1,700 species of lizards and many of them are found in Australia. One, native to that country, is known as the bearded dragon or Jew lizard, and still another is frill about its neck. when the creature is not remarkable for the This lies flat disturbed, but when the animal is attacked or frightened, it is raised like a shield about the head. @ About 220 hours of man-power are re- quired to build a low-priced automobile today.

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Steer Roping at a Rodeo, Just as It Is Performed in the West By BOB BECKER comparatively new example of the in- fluence of the west with its cowboys, broncho busters and “lassoers.” Ever since the days of Buffalo Bill’s wild-west show, boys have tried their hands at throwing a “lasso.” Now, with the ro- deo or cowboy contests gaining in popu- larity in all parts of the United States, the youngsters are learning how to handle a small lariat, not for lassoing but to do tricks with it. The trick roper needs a small rope or lariat and that’s all. Hundreds of tricks can be done with a rope, and the object of the sport is to beat the other roper in ease, gracefulness and number of stunts with a spinning loop. Cuba Crutchfield, one of the great- est ropers of the west and instructor in the art for several thousand boys, advises every youngster wishing to learn to han- dle a lariat to start with not more than sixteen feet of rope. A boy, twelve to sixteen years of age and of average build and height, can usually handle that much rope without trouble. Half to 5 nat ‘"K roping, a sport, 1s another quarter- 564 inch, closely braided cotton rope is de sirable, as a soft strain with no backbone is difficult to spin. So great has the demand for rope suitable for boys’ use that in many large cities the youngster is able to purchase for a reasonable sum a fifteen or sixteen-foot length with a hondo already inserted in it. A hondo (or ring) is a small oval or round piece of metal looking much like a contrivance .made to cut holes in a doughnut. It furnishes an opening of constant size through which the rope is threaded so that a loop may be formed. For trick roping, a metal hondo (the word is Spanish) is needed as it gives weight to the loop and the ounces thus added make it easier to handle. This ring, grooved so that one end of the rope can be curved around it to fit snugly, is held in place by a piece of wire which is run through the end of the lariat and then into the rope. When the wire has been wrapped around these pieces of the lariat, they should be taped until all the wire is been few much covered. The other

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Cuba Crutchfield, Champion Fancy Roper, and One of His hool-Boy Pupils, of Whom He Has Trained Many Thou- sands Each Summer end of the rope also should be wired, in order to prevent it from raveling, and two or three turns of tape passed around it to cover the wire loops. Learning how to spin a rope is com- paratively easy if one starts right and masters a few simple rules. This is mere- ly a matter of practice. Here are Cuba Crutchfield’s instructions to boys (and ilults, too!) who would like to learn to spin a loop. He savs: “A beginner must know how to assume a correct po- sition if he would learn any tricks. Here is position number one: Stand naturally vith your feet spread slightly. Then take the rope in your right hand, about eight- een inches back of the ring, or hondo, and, with the left, ‘feed’ the rope through the ring until about two-thirds of it is in the loop. “When this is done, turn the loop so that it is spread out in front and slightly to your right, the metal ring eighteen inches from your hand. Now, as to the position of your fingers, your first two should hold the loop while the last two of your right hand should grasp that part of the rope not included in the loop. In this way you keep the loop separated from the feeder part. Your left hand is used in much the same way before you start the spin. Your first and second fingers hold the loop while the third and fourth are around the feeder rope, just about halfway between the hondo and the end of the lariat. “To start spinning the loop requires a quick flip which finishes with a _ wide, sweeping circular motion of the right hand, so that the loop will start its round- and-round course. When you start the loop spinning, the palm of your right hand is facing out and the loop is to your right. With a movement of your wrist you turn the loop over and at the same time lean over and with your whole arm make a wide sweep toward your body. As you make this turn, release the circle with your left hand and hold the end of the rope in your right hand.” It takes more than one try to get the rope whirling in a perfect circle, but once going, it is not difficult to keep it spin- ning. And this is the first elemental stunt 565

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566 POPULAR MECHANICS in all trick rop- in g—learning how to spin it in front of you. The next trick to learn is that of jumping in and out of the Co loop, as the ability to do this is the basis \ of dozens of tricks. With the loop whirl- ing one must be able to skip into it with a quick jump and 4, then keep the circle going about the body. Mr. Crutchfield advises beginners to make changing hands around the body their third trick. Standing in the mid- dle of a spinning circle, the idea is to pass the end of the rope from one hand to the other around the body, meantime keeping the loop going. Boys who en- ter the trick-roping contests conducted on the playgrounds of large cities are required to master this trick before being eligible to the finals of the contests. They are also required to learn the “juggling the loop” trick. This is a spec- tacular piece of rope handling which shows how one can, through practice, become complete master of a_ six-foot loop. Starting with a circle close to the ground, the roper gives his loop a pow- erful upward thrust, which sends th: spinning loop above his head so rapid that the eye can hardly follow it. Whe it comes down close to the ground, | shoots it skyward again until. the lo is soon going up and down alternately lightning speed. Next, the trick of “skipping the spoke’ requires quick thinking and quick actio: In this trick, the roper stands in tl center of a spinning loop and jumps ove the spoke, or that part of the rope com ing from the loop to the hand, as it goe around at great speed. Another tric] is that of han dling two smal! loops at the same time. The motto “practice make perfect’’ is graphically il- lustrated in TA trick roping Pa Although boys “ (or adults) may learn ) Center © R. R. Doubleday A Lover’s Knot, Center; and, Top and Bottom, Cuba Crutchfield Showing How the Lariat Is Held in Doing Fancy Spinning |

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POPULAR MECHANICS 567 ( = " A Few of the Fancy Tricks Crutchfield Teaches His School-Boy Classes; in Photo at Right End of Center y Row, the Hands and Feet Alternately Lift, to Clear the Rope as It Revolves

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568 POPULAR MECHANICS number of interesting tricks in a com- paratively short time, the professional trick ropers of the west point out that they have been working at this sport for years, trying to originate new tricks and perfect old ones. Crutchfield, a true westerner born in the cattle country of Texas, says that he has been doing trick roping for twenty-four years. Other famous cowboy ropers, like Chester Byers, holder of the world’s champion- ship trick and fancy roping title; Bob Calen, Tommie Kirnan, and Johnnie Rufus also testify to the fact that it takes years to learn some of the flashy, spec- tacular tricks which they perform in rodeo contests, doing them both on foot and on horseback. Crutchfield originated the roll and somersault tricks, two of the most diffi- cult stunts that a roper (on foot) can at- tempt. In the first, he rolls over and over on the ground while keeping a loop spinning above him. In the second he starts a whirling loop, crouches and then turns a somersault, meantime keeping the big loop whirling without a waver. He makes two or three backward or forward somersaults in succession which shows complete mastery of the rope and com- bines acrobatics with rope spinning. Other difficult and interesting tricks which professional ropers are able to do, Turning a Series of Somersaults or Roll- ing Over and Over While Spinning the Rope Are Two Tricks Requiring Many Months of Patient Practice include jumping through the cartwheel, the dog trot and spinning the circle. In the first, the roper starts a circle about six feet in diameter in front of him. Then he gives it a sharp pull toward his body which brings the loop toward him. At the correct moment he jumps through it and then brings it back again for an- other jump. In spinning the circle, the roper keeps one foot out of the loop and the other in and.then passes the loop under his foot. It takes many a quick skip and jump to do this trick. Although roping tricks done while the roper is on the ground are interesting and as difficult as any devised, because the) involve acrobatics, trick roping from a horse is more spectacular. Here is where the professional ropers are in their ele ment. They spin loops around their horses, throw circles at galloping riders, catch horses by one foot, four feet or around the head and even toss a circle large enough to take in two or three riders. These tricks represent the last word in dexterity, quick thinking, and timing, as several ropers are able to throw a big loop backward at a galloping horse at just the right second to catch either fore or hind feet. Although a healthful outdoor pastime which aids muscular development and thus is of benefit to boys who aspire to master this new type of western sport, trick roping is of practically no value to the cowhand in his everyday tasks with horses or cattle. It is a sport pure and simple, and like steer riding, steer wrest- ling and broncho busting a kind of fun , that originated in the daily life of a cowpuncher. But of all the cowboy sports, trick roping is the least noisy and that which calls for the greatest dexterity.

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POPULAR MECHANICS 569 sSLINDS PROTECT HOUSES FROM STORM DAMAGE Outside window blinds are not <tensively used these days ex- ept for decoration, but eir efficiency in protect- ng houses and other tructures from storm lamage has been so con- incingly demonstrated hat builders are wonder- ng if a mistake has not een made in discarding them. In Cuba, where hur- ricanes are not uncommon, all buildings are fitted with hutters, and although the Florida storm last year damaged hotels that did have blinds, the havoc was much less than t would have been had there been no protection for the windows, it is believed. If a wind of sufficient strength blows in the glass, a pocket is formed in the interior of the building, giving the storm additional opportunity to cause destruction. By pre- venting this, the shutter decreases damage. OBSERVATION BOOTH IS BUILT IN FRONT OF LOCOMOTIVE For track and tunnel inspection on a western railroad, an engine has been equipped with a glass observation cage in front so that ob-

These Scales Are So Nice- ly Balanced That They Register the Weight of the Sweat on a Man’s Brow

SCALES THAT “WEIGH EMOTION” AID MINING TESTS Investigators of the bureau of mines and of the Pittsburgh experiment station have been conducting a number of interesting tests recently to determine the effects of weather and temperature conditions on workers. In connection with the research, scales so delicate that they could weigh the sweat on a miner’s brow to indicate how energy had been expended under cer- tain conditions, were used and so accu- rately adjusted that it was considered fair to say that they could “weigh emotions,” since any difference

— servers may ride close to the rails and obtain an unob- structed view of the entire right of way. The controls are in the cage,so that the engineer may ride with the inspectors and stop the loco- motive without the need of signaling. The fireman occu- pies his usual post in the cab. There is room for several men on the long up- holstered seat that

in weight due to nervous excitement or other moods, was recorded. One of the principal uses of the scales was in re- lationto the amount of heat and mois- ture that will be thrown off on the average bv a large audience assembled in a theater or other public building. These data are con- sidered of great im- portance to heating and ventilating en-

extends across the compartment. Enabling Inspectors*to Gain a Close View of the Track; the Observation Booth on Locomotive gineers as well as to health officials.

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570 POPULAR MECHANICS CAMERA TAKES FIFTY PICTURES ON SINGLE ROLL OF FILM Illustrating the Size and Operation of the Fifty-Ex- posure Camera Weighing only twelve ounces including the film, a small camera now on the market takes fifty pictures on one roll and is so simple to operate and load that it offers distinct advantages to the tourist or other person who wishes to make a pictorial record of a journey at little expense. The camera is approximately two by two and one-half by four inches in size, has a rapid lens and is equipped with a full range of speeds and stops. The negatives, slightly less than an inch ‘ special projector made for this purpose The film thus replaces glass slides for “still’ views. In operation, a small dial on the front of the camera keeps track of the number of exposures made. The winding is done by means of a lever on the back. STRAWBERRY GROWN ON TREES TO AID COMPLEXION Among a number of strange fruits re cently brought to this country was a giant strawberry which is said to have proper ties tending to reduce the weight and im prove the complexion of persons who eat it. The berry is found in China, along the coast south of the Yangtze river. It grows on trees, has beautiful flowers, and bears half a dozen crops a year. Efforts will be made to develop it for cultivation in this country. MEMORIAL TREE MARKS SCENE OF FAMOUS INDIAN TREATY Preparations already are being made for celebrating the 150th anniversary of the defeat of the British near Vincennes, Ind., by George Rogers Clark, a victory which contributed largely to the saving of the great middle west to the United States. The plan is to have a weekly observance of the occasion throughout the year 1929. A memorial building is proposed, with murals showing square, occupy a roll about the length of a six-exposure film for a camera of post-card size. They may be printed in sections, that is, several de- veloped on one sheet of paper and sired; can be en- larged to three and one-quarter by four and one-quarter size in a handy en- larging device or be printed on posi- tive motion-picture i tue Dect DUR EWABNUT ORC then cut apart if de- ois qeiareye : ao Wires scenes of Clark’s victory, and the structure later is to be converted into a national shrine. The anniversary will also recall thetreaty between Tecumseh, famous Indian chief, and President Wil- GAH 7 liam Henry Harri- son, by which peece was made between the whites and In- dians. A memorial tablet has been placed on a tree which stands near the spot where the film for showing on a screen through a Marking an Important Spot in American History; the Treaty-Tree Tablet Recalling Chief Tecumseh | treaty was made in August, 1810.

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POPULAR MECHANICS 571 SEEING IN THE DARK BY MEANS OF “BLACK LIGHT”

THE INFRA-RED RAY AS NOW USED FOR TELEVISION THE SPECTRUM -THE VIS- IBLE AND INVISIBLE RAYS ULTRAVIOLET INVISIBLE TU THE ver "UMA cp VIOLET EYE f Me” a HUMAN EYE e RECEIVING END TO HUMAN EYES THE ROOM SHOWING IMAGE IS IN COMPLETE DARKNESS INFRA-RED —- ” ie INVISIBLE TO THE HUMAN EYE BUT INFPRA-RED RAY IN USE IN WAR VISIBLE TO THE UL! SENSITIVE CELL RECEIVING SCREEN

THE APPARATUS USED TO RECEIVE THE VIEW ILLUMINATED BY THE INVISIBLE BEAM OF THE INFRA-RED SEARCHLICHT ANDO RENDER 'T VISIBLE TO THE EVE QF THE OPERATOR

NFRA-RED SCREEN DOTTED LINES SHOW InwISIBLE THE RADID MOVEMENT INFRA -RED RAY MOTOR ~ AMPLIFYING OF THE SPOT OF LIGHT TVBES BVILOS UP THE SCENE REVEALED BY THE RAYS

Copyright, The Illustrated London New Using Invisible Infra-Red Rays and a Fluoroscope as a Receiving Screen, an English Inventor of Television Apparatus Has Developed an Invisible Searchlight for War Use

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572 POPULAR MECHANICS

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Domestic-Science Class in Traveling Auto Bus; Interior of the Well-Equipped Car for Giving Instruction in Latest Home Practices to Rural Communities AUTO BUS FITTED AS SCHOOL FOR DOMESTIC SCIENCE To help spread the doctrine of better health, homes and cooking, a lighting company maintains an auto bus equipped as a school and demonstration room with a capacity of thirty-seven “pupils.” With specially trained experts and lecturers in attendance, the traveling “college” visits cities, towns and villages in an area of more than 400 square miles, where house- Wives can see tests stove, table, cupboards and space for gas and electrical appliances are features of the equipment. Comfort and visitors are assured by special means for ventilation and an extra door at the rear of the bus for emergency exit. safety of CHURCH TO RESIST HURRICANES HAS STEEP ROOF After a severe wind had destroyed a church building in Maryland, extra pre cautions were taken

with the latest kinds of cooking equipment, listen to talks on prepar- ing special on buying and other pointers in domes- tic management. Special attention is given the question of proper illumina- tion for the home, even to matters of correct wiring. Seats are arranged at the sides of the bus, leaving a wide foods,

with the new struc- ture, to make it as nearly proof against a repetition of the disaster as possible. It is and has an extremely steep roof, so that winds can over it without encounrter- ing much resist- low sweep ance. The walls are three feet thick and taper up to eighteen inches at the point where the rafters rest. The

center aisle. A sink with running water, Built with Thick Walls to Defy Tornadoes; Roof Is Intended to Let Winds Slide Off force of winds is Steep also broken by trees.

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POPULAR MECHANICS 573 \ELTING BULLET MADE TO AID CRIME WAR omposed of glycer- stearin and an anti- ptic compound, a eathless” bullet, de- ed by an eastern in- entor, is imtended to und a person without ling him. It melts after ntering the body, leav- a clean wound, but as force enough to top a man at twenty eet, and would be fatal f striking a vital spot. A eature of the bullet is at it makes twice -as 1uch noise as an ordi- nary one when fired, so aie seers t would be of aid to a itizen in spreading an larm. Tests showed that t penetrated a one-inch pine board, and t was also shot into a ham to demonstrate ts properties. MOTOR CHAIR FOR INVALIDS IS EASILY CONTROLLED For invalids and cripples, a wheeled chair containing an easily operated mo- tor has been introduced in Germany. It The Invalid Can Take an Outing Unattended, on This Motor Tri- cycle; Controls Are within Easy Reach and Simple © Henry Miller is simple to steer and has been designed with special emphasis on safety. @ Regions with the most intense sunlight produce the most highly colored fruits. How the Steel “Rib” Holds Up Mountain While Men Pierce Continent’s Backbone; Scene in Moffat Tunnel STEEL RIB FOR USE IN TUNNEL PREVENTS CAVE-INS Engineers estimate that than $2,500,000 will have been labor costs and, doubtless, several lives spared in digging the Moffat tunnel in Colorado, through the use of a huge steel canti lever girder for supporting the top of the while Three of the more saved in timbers are put in place. girders used. Each is sixty-five feet long, ten feet high, passage have been eighteen feet wide, and weighs fifty tons. The girder is built of structural steel and somewhat resembles a centipede lying on its back. It has projecting arms which support the arched section of the tunnel roof, while drilling, blasting and timbering of the bench on which it rests are in progress, and, as the work proceeds, it is advanced on a track by chains and attached to an air hoist. The used to place the enormous timbers which hold up the roof, a task that usually calls for many men and is often attended disastrous slides. The girder vised by George Lewis, general manager of the construction work on the tunnel and a mining engineer of many years’ means ot cables apparatus is also with was de- experience.

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574 POPULAR MECHANICS HOW ACCIDENTS KILL TWENTY THOUSAND IN YEAR NS Common Acts That Result in Hurts and Deaths; Youthful Craftsman Courting Cuts Inviting a Serious Fall by Standing on Edge of Tub, an Everyday Mistake It’s Fun to Climb, but What if the Porch Rail Happened to Break? = Flirting with Serious Injury or Death by the Use of Oil to Start Fire Lighting a Match in Clothes Closet, a Common Cause of Costly Blazes Flatiron Cord Is Ragged and the Inquisitive Child Is In- viting a Tragedy Both Right and Wrong; Keep Matches off Stove and Have Gas Oven Open in Lighting Looking for Gas Leaks with a Match and Pretty Sure to Find Serious Trouble Appears Safe but It Isn’t; Never Use Rocking-Chair as a Stepladder c) National Safet Council

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POPULAR MECHANICS 575 |) OCKET RADIO SET AID FOR POLICE IN CRIME WAR with miniature io-receiving sets by ice in an eastern city e been so successful it it is planned to uip the force with the truments to aid in the against crime. The can be carried in a x no larger than a ests varet case and consists a single vacuum tube, all batteries, collapsi- ear phones and an rial attached to the po- sleeve or the On the ceman’s pel of his coat. uniform, a tiny electric ht, suitably mounted, which flashes a enal from the central station telling him » listen in. The sets are effective over a inge of three and one-half miles, accord- ng to the inventor, and operate on a wave- ength of fifteen meters, too short to inter- fere with reception by ordinary household In case of a holdup or other crime, a general alarm spread from the main station would notify every police- nan on duty within a few minutes to be on the watch for the fugitives. The news would be broadcast by voice, saving the trouble of learning a code. itside of his ere 1S vireless. NINETY-FIVE-POUND TOPAZ WORTH THOUSANDS One of the largest single pieces of topaz in the world has been added to the Smith- onian Institutien collection from It weighs ninety-five pounds or nearly 250,000 international metric and is valued at approxi- mately $3,000 in the rough. Another large topaz is in the Field museum of natural history. It weighs in the neighborhood of 100 pounds. carats, 3razil. Huge Jewel from Brazil for the Smithsonian Institu- tion; the Ninety-Five-Pound Topaz Karl Illava Completing the Clay Model for the War Memorial; He Is Plac- ing a Gun in the Hands of the Charging Figure : WORLD-WAR MEMORIAL COST HUNDRED THOUSAND Notable because of the realistic facial expressions of the figures represented, a World-War memorial, New York, cost $100,000 and over two erected in took years to complete. It shows soldiers in heroic size, as though ‘in action, fighting, charging and suffering the pain of wounds. FORTY-TON BANK-VAULT DOOR HAS TWENTY BOLTS More than forty-five inches thick and se- cured by twenty steel locking bolts, five inches in diameter, the circular door of a bank vaultina Pennsylvania city is made doubly secure against theft as it is water-tight when closed, preventing the introduction of liquid explosives. The door weighs 80,000 pounds, is more than eight feet in diameter at the front, and is so that it can easily beswung by hand. nicely balanced

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POPULAR MECHANICS can be jotted down, while the strip is wide enoug! to record five games, gi ing a permanent recor for comparison, of ho each card was played in each game. Radio fan can take the bridge prob lems announced in ad vance, play them several times and record - thei: play, and then save the slips for reference when the same hand is played Bridge Game Designed to Be Played with Radio In- structors; the Movable and Washable Tabs Can Be Hidden from Oppo- nents’ View, Placed on the Board for Dummy, or Turned Down for Tricks Taken and broadcast by the bridge expert, compar ing the expert’s play with LJ} the previous trials, and study the mistakes that may have been made. INSIDE OF ROPE WEARS MOST Lubricating ropes to keep them in good con dition has found been BRIDGE GAME LETS RADIO FANS PLAY LESSONS IN ADVANCE A bridge game by which radio fans who tune in on the broadcast card lessons, or others who are studying bridge from books, may set up any problem hand and play it over until all its possibilities have been mastered, is one of the newest things in card instruction. The of four boards, game consists one for each plaver at a full table, or they may be used separately for individual practice. The “cards” are merely “pips” showing the suit and num- ber, and are made of washable celluloid, so they can be used indefinitely. They are held in small leather tabs, from which they can be removed whenever a new hand is set up. The tabs are attached to a long wire rod, enabling the cards to be set up on edge, so that other players cannot see them, laid flat, face up, for the dummy, or turned over, face down, when a trick is taken. A long strip of paper, held down by clips, is ruled so that the sequence in which each card is played helpful, since the wear and strain is frequently on the interior, where the twisted fibers cross each other, rub together and are likely to break. Tallow, lard and boiled linseed oil are widely used in treating the fibers to reduce friction. One of the standards for judging rope ts the length of its fibers, long and strong ones characterizing the better qualities. FLINT GUN FOR LIGHTING GAS REPLACES MATCHES A modern development of the old sys- tem of starting a fire with flints is seen in a household lighter now popular in France. It is essentially a small spark gun using a flint ¢o ig- nite gas jets or to kindle ; One flint is to be equivalent to 600 matches and several are furnished with each lighter. The appa- ratus eliminates the fire risk from careless throwing away of glowing matches. blaze. said

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HEWING GUM FOR AIR PILOTS HELPS IN DESCENTS Gum chewing is recommended for pilots the Royal Air Force flying-training nual, published in England, as it pro- les saliva and helps overcome the dif- Itv experienced in swallowing during cents as a result of parched throats. lowing aids in equalizing the air essure within the ears when descend- from a high altitude as it opens the ow passages leading from the back he throat to the inner side of the ear- um. In sudden downward flights, au- rities recommend “clicking the ears,’ hich means pinching the nostrils and rcing air from the chest into*the nose til a clicking sound is heard in both rs. The manual also warns against ex- ive smoking that may lead to throat ngestion, and suggests proper care of teeth as another item of hvgiene to hich special attention should be devoted. COOK MODELS HOTEL IN GLASS FROM OLD ELECTRIC LIGHTS Glass used to support the filaments in | electric-light bulbs is the principal ma- iala pastry cook has employed to fashion 1otel 1 } I realistic model of a thirteen-story Resins Glass from Discarded Electric-Light Bulbs Was the Principal Material Used in This Model of Hotel Cleveland. Ohio. The pieces are fas- tened together with glue and the replica glass floors, a tiny piano that plays is ‘handeliers, figures of dancing couples nd other lifelike features. POPULAR MECHANICS 577 J Sketch Showing How Light from Street Lamp Shines through the Transparent Stop Sign TRANSPARENT AUTO STOP SIGNS LIGHTED BY STREET LAMPS Fitted with lenses on the rear side, a type of traffic sign now on the market, is distinctly lighted at night by the rays from the street lamps, so that it requires no batteries or wiring The sign ire durably constructed of steel, with legends in raised lettering against a vellow bacl eround. In installing them, it is onl necessary to see that thev are piace 1 in relation to the street lights so that the 17 lenses will receive full illumination FIX CENTER OF NORTH AMERICA NEAR DEVIL’S LAKE, N. D. Recent surveys place the veog! iphic center of the North American continent a few miles west of Devil's Lake, N. D. The spot is at forty-eight degrees ten minutes north latitude and 100 degrees ten minutes 1 west longitude. Since the lake is close to the center, it becomes a natural monu ment, and, already a noted scenic place, gains additional distinction.

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578 POPULAR MECHANICS HOW GRAND OPERA IS BROADCAST FROM STAGE z ltorophones|* over Aud/ence BA VYticrophone Ror FAIINOUNCEer Lehind Courtesy Chicago Evening P Drawing Illustrating How the Microphones Were Arranged on the Stage and in the Auditorium Theater for Broadcasting an Act from the Opera ‘“‘Faust”’ Successful broadcasting of the second “Faust” from the Audi- torium theater in Chicago was accom- plished by distributing fifteen microphones about the stage, orchestra pit and over act of the opera the audience, and employing a mixing panel to blend and subdue the tones. The result was pronounced one of the most satisfactory ever achieved in radio trans- RED DIAMONDS MOST VALUABLE BLUE ONES NEXT Instead of being colorless crystals as is popularly supposed, diamonds are found in a great variety Of colors and are priced according to their hue as well as their size and freedom from imperfection. Red diamonds are rarest. A small one, found at Kimberley recently, was valued at $4,500 in the rough. The blue stones are considered next in point of worth, and mission of so complex a program—voices and a large orchestra requiring careful handling in order that the effect might not be spoiled for the radio listener by too much volume from any one set 0! instruments or by the solo vocal parts being indistinct. For several days before the performance, engineers were busy in stalling the equipment. the pure grass-green gems third, while vellow diamonds are as cheap as the red are dear. There are brown diamonds of comparatively no value. One of the most costly diamonds is the ten-carat stone purchased by the Emperor Paul of Rus sia at a price of $100,900. monds are rare and bring large sums. The value of pearls is also based largely on color, the most highly prized being the black ones and next, the pink. One of the largest of this color was taken from Orange dia-

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: POPULAR resh-water mussel in a tributary to the sissippi river. It is three-quarters of nch long and valued at $40,000. As diamonds, the yellow pearls are the valuable. Rubies, sapphires and the iz are sometimes improved in color treating them with radium which seems burn out their impurities. rURN SAWDUST INTO CHARCOAL TO FEED CHICKENS Charcoal, suitable for feeding to chick- is being produced by an improved rocess in the state of Washington by larring sawdust in a rotating retort. It said that the method is far faster than ler processes and, since use is made of aterial that otherwise would be wasted, additional saving is realized. Char- il has been found beneficial to fowls as 1 aid to digestion. ELECTRIC WATER-PIPE HEATER DOES AWAY WITH DIRT Connected to the house water-supply stem, an electric heater controlled by push button is said to be economical nd safe, and has the additional feature r being noiseless. When the heating units wear or burn out, they can be re- iced without the need of draining the iter from the heater, and safeguards e provided to eliminate the danger of verheating. MECHANICS 579 The Bell on Its Way to the Steamer with the Floating Crane; It Was Moved Alongside the Vessel and Swung Aboard, Then Secure- ly Fastened for the Journey across the At- lantic; It Weighs Nearly Eighteen Tons Pr. @&A LOADING BIG BELL ON STEAMER REQUIRES SPECIAL CRANE Ordinary wharf facilities were unsuited to the loading of a huge bell for a Phila- delphia department store at an English port, so a crane on a floating platform was rigged and the bell towed with a tug alongside the steamer. It weighs seven- teen and three-fourths tons. FARM-CROP YIELDS PER ACRE GRADUALLY INCREASING In the older sections of the United States, the farms are not wearing out but N opel) — rays Electric Heater, Installed with Water-Supply Tank, and the Current Control Panel are producing greater yields per acre, ac- cording to reports. Since 1885, the aver- age vield of corn has increased eighteen per cent, wheat, seventeen per cent, oats, fourteen per cent and potatoes, thirty- nine per cent.

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Diver Going over the Side to Descend to the Sunken German Battle Fleet, : While a Companion Stands Ready to Don the Helmet _— away from the track of steamers on the lonely coast of the Orkney islands at Scapa Flow, an army of divers ‘for two years past has waged a battle with violent gales and shifting tides and sands for the possession of half a million tons of valuable metals. They are trying to raise the vast hulks of twenty-two great battleships and cruisers of the former German high seas fleet sent to the bottom by Admiral von Reuter in June, 1919, when he gave the order to open the seacocks and scuttle the vessels to prevent them from falling into the hands of the allies. Important 580 ING a By HAROLD documents are believe to lie in the safes and a: chives of these drowned ships, but the prize for the salvors is the win ning of the half millio: tons of valuable metal represented by the fit tings and the sunken armament o craft. The cost of the operation has reached into si and two out of twenty-five destroyers remain to be from The 28,000-ton battle ship “Hindenburg” h: concentrated the most strenuous efforts of the divers. Her rotted hull and slimy decks are pressed down with a weight of 56,000 tons of figures, now onl their grave ~ raised water. Three times, since August, 1926, she has been lifted to the sur her great rents patched and her _ port- holes screwed home, and each time inrushing water has burst open her patched rents, and swept her back to the bottom. The story of the adventures of the divers on the “Hindenburg” face, is an excit- ing one. The first man to step on her decks, seventy feet. below the surtace, quickly pulled on the shot rope for help. A monstrous forest of seaweed, with stalks as thick as a man’s wrist and leaves eighteen inches wide, trailing fif- teen feet in length, was seen growing out of her The diver tried to wade through this submarine jungle, but was baffled. Several other sides. divers arrived,

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LE ET from Davy ones’ /@cker” r. WILKINS —ee 8s med with double-bladed daggers, and ied their way to the portholes. Now began a search for the plan of ; , owes Mr. e “Hindenburg. This was necessary ga ~ locate all apertures which needed Lee iling up before the water could be iy mped out or expelled by the cost ethod of compressed air. In the inky ickness below, the diver’s electric torch useless even three inches away from object, and it is fatally easv for his line to catch in an unseen cabin door- as he gropes his way between decks. hey found the precious plan in the chart- om, etched on steel and varnished. [welve divers then set to work to tun- nel under the sub- erged hull to get le seacocks un- der the engine room, by the opening of 1 ) 1 hich the “Hinden- Battle Lookouts at the Mast- head, Bridges and Funnel of the Battleship ‘‘Hinden- burg,” as Salvage Crews Had Begun to Raise the Great Warship Photos « Sport & General

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POPULAR MECHANICS PONTOON - —_ >i — - Sa NG Ss! kIFTING HOOKS PLACED IN PORTHOLES OR HOLES CUT BY DIVERS Courtesy the I

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POPULAR MECHANICS 583 eel a LARGE TUBES FOR s LOWERING PUMPS INTO HULL —__ DOCK USED AS PLATFORM FOR PRELIMINARY WORK SUBMERSIBLE PUMP Se SHIP RAISED HER BOWS - WHEN FORWARD PART WAS KPUMPED OUT THE SHIP DRAWN INTO SHALLOWER WATER AND GUNS,FUNNELS AND MAST REMOVED ee PUMPED OUT OF WATER ited News

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584 POPULAR Two Big Guns in the a Turret above Water, and the Pair in the Forward Turret Just Visible beneath the Surface MECHANICS Other divers with com- apparatus scraped the bar nacles off the ship’s bottom and sides While the divers were busy at this task, three great whales approached and swam round the hull. Forty pumps were started, capable of removing 60,000 tons of water in twelve hours, and seventy divers, work ing in continuous shiits, began on the work of stopping and sealing 700 holes in the hull. They blasted away rock pinnacles with graduated charges of dy namite, and blew off the ragged edges of the rents in the armorplate, in prepara tion for the enormous task of applying and water-tightening the patches. burg” was sunk. pressed-air Tough steel, fourteen inches thick, was burned through in sixteen minutes by an electric arc. Such a dazzling light blazed from these that the divers had to wear protecting shields over the windows of their helmets. The rents were stopped, and the portholes sealed, but by this time the “Hindenburg” had sunk deeper int: the ooze of the bottom. Tons of mud had poured into her portholes and power ful jets of water were driven by arcs com- pressed air upon the mud, expelling it from the hull to the sea bed. moored pontoons on side of the sunken battleship. Strong steel hawsers were passed under her hull, and attached to winches on each pontoon, and men strained at windlasses and ropes until the ship swung delicately balanced in the cradle of immense hawsers. Word was given to the divers: “Stand by to lift ‘Hindenburg’”; and on Au- gust 19, 1926, in a heavy gale and drench- ing rain, the flagstaff rose above the water followed by four twelve-inch guns. An hour passed, and the timbers of the upper deck emerged. The pumps were expelling 10,000 tons of water each hour from the hull, but the battleship slowly heeled over to an angle of thirty degrees. Three months of exertion Lad been wasted—she was flooded and went to the bottom again where she now lies upright with her starboard side anchored down by the sinking of some of the salved destroyers. The gigantic task of raising the remaining eleven battleships, three battle cruisers, eight light cruisers and the two destrovers still unsalvaged, probably will take about nine years. Divers then each

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POPULAR MECHANICS uw uv aed 13 74 eo, 7 4B AON Zo vs = a i. 2 ———— Huge Pumps Emptying the “H denburg”’ of Water Preparatory Lifting the 27,000-Ton Ship man Cruiser, While Other Salvag Vessels Lie in the Background vo aE te. in- | _— to from > aan Its Seven-Year Grave, and, Below, Sm , Salvage Ships Working on One Ger- ed | i Top Phot Cc) The Londor i Times

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S60 POPULAR MECHANICS Shadow Picture of Gear Which Clearly Reveals Any Defects in the Cogs; by Comparing This Shadow wit! a Master Pattern on the Screen, Imperfections Are Quickly Located HOW SHADOWS HELP TO KEEP highly specialized inspectors could a hie THE WORLD IN GEAR without it In keeping with the demand for greater CRUISE IN MOTORCYCLE BOAT accuracy in the manufacture of machine AROUND WORLD PLANNED parts, an instrument that makes use of the simple principle of shadow pictures, Plans for a tour around the world has been devised for the inspection ot London, in a small motorcycle boat gears and other units. It consists chiet has designed, are being made’ by an | ly of a microscope and a projection ap lish inventor. The crait has a side paratus by which a shadow of the part float and is equipped to withstand roug under observation is cast upon a screen, magnifying an error as pant. According to reports, he tested th mal as one one-tnou- boat with food results on a small body sandth of an inch to a water at Hampstead heath. quarter of an inch so that it can readily be detected The shadow cast by the part is compared toa master image that is pro jected upon the screen at the same time for the purpose of speedily de- tecting errors. . An ad- vantage of the instrument is that it can be operated by persons w ithout | special training and yet gives results that only Designed for World Cruise; the Motorcycle Boat weather and give protection to the occu

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POPULAR MECHANICS EW RIVER REFUGE FOR DUCKS AND WILD GEESE urther protection for d ducks, geese and er fowl has been as- red in a new bird reser- tion recently estab- hed by the government two small islands at e junction of the Co- bia and Walla Walla ers in Washington, ich will be known as e Columbia river bird fuge. The rocky islets brace uwvout eight and e-fourth acres of und and for many ears have been a favorite sting place for wild rds. The fact that the eserve is not easily accessible by man make it all the more advantageous to e game. It is under the jurisdiction of e U. S. biological survey. WATCH WITHOUT HANDS TELLS TIME BY MOVING DIAL \ watch without hands, which tells the me through an indicating figure for the hour, appearing in a slot in a re- volving dial, has been introduced in France. The edge of the dial is stationary and bears the sixty- minute marks. Inside their cir- cle is a revolving dial bearing an ornamental ar- row head, at the tip of which is a small slot in which the figure indicating the hour appears. If the figure showing is eight, for example, and it is under the ten-minute mark, then the time is 8:10. The watch is particularly useful in those continental countries like rance where the day is divided into hours numbered from one to twenty-four, in- stead of a day and a night. uw oO NI Blind Children Feeling the Huge Relief Globe, to Gain Knowledge of Geographical Features BLIND USE FINGERS TO “SEE” BIG RELIEF MAP Blind children at the Perkins institute in Watertown, Mass., are taught to study, play and work in spite of their handicap, and much is done toward fitting them to earn their own living. By means of a lief, thev learn geog- special globe in re raphy, their keen sense of touch enabling them to “visualize” the outlines and con- tours of the continents and countries. The surface of the sphere is especially marked so that they can interpret it easily. ELASTIC SEALING FOR BATTERY WON’T CRACK OR RUN For sealing storage batteries, filling cases of B-eliminators, and similar work, an elastic material, recently intro- duced, is said to have distinct ad vantages in that it will not crack in extremely cold weather and will not run under high temperatures. It is also said to adhere firmly in spite of vibrations, is easily cut for repairs and has a brill rrilliant surface when torched.

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955 POPULAR

To Help the Pedestrian in Crossing the Street; the Moving Arrow in Center Indicates Walking Time TRAFFIC-SIGN ARROW TELLS TIME BETWEEN LIGHTS \ revolving arrow which indicates the length of time before the next change, is the feature of a traffic light designed to make driving faster and easier. The pointer, which is visible a block away, turns slowly and points straight upward at the moment the lights change. A driver approaching the signal is thus able to adjust his speed so that he will reach the intersection at a period when the “go” light is on. Many less sudden stops and starts will result, the designer insists. The signal will also reduce the danger of the pedestrian, who often leaves the curb on- lv to find himself in the center of the street when the light signals change. NATURE’S BALANCE WHEEL Nature seems cruel at times, especially in the destruction of various forms of life, but if all creatures were allowed to go on multiplying unchecked, serious results soon would follow. Statisticians estimate that if the eggs of a codfish were all al- lowed to hatch, start their lives and mul- MECHANICS tiply in turn, but a few years would }) required to choke the seas with this kin of fish alone. In less than ten years, rat would greatly outnumber the human po; ulation if they lived unmolested. If deat did not occur among the birds, in twent years, the descendants of one pair woul number thousands of millions and, in few seasons, flies would sweep the entire earth if they all multiplied unchecked Another expert calculates that, if all th human beings born lived to be seventy years old, sixty per cent married and had but two children who also lived to be sey enty, in 150 years the earth would hx a mass of humanity hardly able to move SPEECH PRODUCED BY BELLOWS THROUGH HUMAN HANDS Using a bellows operated by the foot an organ-pipe reed and his fingers, an English inventor has succeeded in imi tating the human voice with remarkable clearness and fidelity. He can produce the sentence, “Hello, London; are you there?” the reed serving as vocal organs and the fingers as the tongue and lips The experiment illustrates that the natural voice is largely a mechanical result of muscular and nervous action The Speech-Mak- <i d ing Apparatus; Air Supplied by Foot Bellows Is ‘*Tuned’”’ by the Hands at the Nozzle

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odi ke ng Chips Where the Steam Is Allowed to Escape from the Pulp Material after “Firing” from the Guns; the “Cyclone” at the Wood-Waste Salvage Plant Sawmill Waste Is Cooked, Turned into Pulp and Then Converted into Boards for Many Uses | * a new process for utilizing sawmill waste, just launched in Mississippi, the labs and edgings that formerly went to he trash burner are chopped up, placed n chambers where they are cooked with high-pressure steam, and then shot out in the form of pulp. This is pressed into hoards; which are formed.without the ad- lition of any binder. The resulting product differs from the various wood substitutes now on the arket, as it consists entirely of wood, irom which none of its natural elements have been removed. The process was originated by W. H. Mason, who achieved fame during the orld war by inventing a way of extract- ing turpentine and rosin from vhile it was being dried. At the Mississippi plant the waste wood is first thrown into a “hog,” lumber an inclosed, studded with knives, which reduces the material to chips. The heavy iron wheel ments and sawdust are sent to the boiler for use as fuel. The material to be converted into fiber is whisked through a blowpipe to the chip bins. From these bins it is fed into chambers, known as “guns,” built of The guns point downward and are filled at the upper end by means of pipes lead- ing from the breech of the gun is then closed and steam is chips are screened, and the smaller frag- + room hea\ vy steel. bins. The admitted The steam is at the enormous pressure of 1,000 pounds to the for a few seconds. square inch and is supplied from boilers that are said to be among the most pow- erful in the world. Small ports at the base of the gun are next opened, and the material is shot out at a speed of 6,000 feet a second. This

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590 POPULAR MECHANICS L much stronger than dinary wood. This tak a fine polish, and can used for furniture, floo: ing, and many other pur It is already bi ing employ ed by a nu poses. ber of automobile cor panies as a backing upholstery in cars t have steel bodies. As is impervious to wa Trimming and Edging the Artificial In- sulation Board; the *“‘Guns’” Where Steam Pressure Is Applied, and Sample of Product violent “explosion” of the boiled chips tears them into tatters, separating the fibers ot the w ood but leaving each fiber coated with lignin, which serves as a nat- ural cement. This is next whisked through a long pipe to a “cyclone,” in which the steam is allowed to escape into the air. It then goes to a beater, which completes the separation of the fibers, and thence that used in making for producing it in an end- to a machine, similar to paper less W eb, where it is formed and cut into sheets. The sheets are finally taken to steam-heated hydraulic presses, where the board is pressed into shape and the last bit of moisture removed. Two distinct types of board are made. One is an insulation board, use in walls, ice suitable for It permits the direct application of plaster or can be decorated without a plaster coat. boxes, ete. The other product is a thin grainless board, prove of use as a root covering. SLIDING TAB ON FILE CARD AID TO FOLLOW-UP WORK The usefulness of a card-index system, particularly in follow-up references, increased by a sliding indicator which is attached to a slotted card and simplifies finding data relating to any particular day of the week or month. At the top, the card is printed with numbers indicating the davs of the month, the days cf the week names months. dicator is pointed and the of the The in 1819 202223 Thu Fri and also has an Sept. Oct open oval, expos- ing the name of one day at a time. By moving the slide to the proper date for that card and filing the index according

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simple date system, it is easy to keep cards calling for action on special in an arrangement that tells at a nce, what dates are filled. An addi- il feature of the system is that the may be removed from the file box carried in a pocket memorandum case. -UBBERIZED SILK BATHING SUIT WEIGHS BUT SIX OUNCES Several advantages are claimed for a ber bathing suit recently introduced at outhern beach. It dries quickly so that - wearer may don street clothing within few moments after leaving the water without removing the suit. Its elas- tv permits free movements, and it chs but six ounces. The material is a fabric which has been rubberized to ke it non-absorbent. TELEPHONE STANDS FOR TAXIS TO RELIEVE TRAFFIC For the convenience of telephone sub- ibers and to relieve traffic congestion, erlin officials have installed fifty tele- one stands along the streets for sum- oning cabs. They are at the service of hone patrons and are intended to reduce e number of idle cabs. By this system, he vehicles will remain in a near-by park- ng space and respond only when called. POPULAR MECHANICS 591 Sidewalk Cab-Telephone Booth in Berlin Inventor and His Clock, Showing the Passages down Which the Balls Roll and the Windmill at To; CLOCK RUN BY BALLS AND WIND REQUIRES NO WINDING “Perpetual motion—almost,” sa) Francisco inventor concerning a_ clock which he has constructed, and his verdict is regarded as sound, for the clock does run without winding and almost “by itself” except that,-now and then, the wind mus be relied upon to give it a boost rhe driving force is provided by a number of ] 1 drop into a cup on the 1 ‘ t =) 1 > small balls whie driveshaft and operate the works by their weight. At each quarter of a revolution when the ball falls from the cup, it is re placed by another. The spent ball roll down a chute and into an elevator, whic] is run by a tiny windmill, and is hoiste to the top again to repeat the cycle. There are 250 balls in the clock, sufficient to p1 vide motive power for five days in case the wind does not blow hard enough to oper ate the elevator. @ Popular Mechanics Magazine does publish the name of the maker or seller ot anv device described in its page ut this information is kept on file be furnished, free, by addressing our Bu reau of Information.

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SQ? ELECTRIC-LIGHTED RADIO MASTS GIVE BRILLIANT DISPLAY Using Radio Masts for Night Displays; Scene Outside a Los Angeles Motion-Picture Studio Outlined in brilliant el ehts. the 150-foot radio masts in front notion picture studio in Los Ange 1 isible at a great distance and form a novel set ting tf he buildiu t | s fi luminate it loodlight Since the slet ce oO the radio towers can hard be seen at night. the effect of the chains of light, apparently unsupported, is unusually attractive. THIEVES ARE TRAPPED BY DYES FISHHOOKS AND WHITEWASH Piles of sometimes vards bv } coal stored in open 1 the wit protected against theft simple expedient of covering them whitewash so that In be detected. t are occasionally trapped by connecting ob- with an larm in the dala office, so that “1 any removal can easily various hotels, thieves jects electric man- ager’s a signal is given in case an attempt is made at removal. One of the i | most effective aids to the detective at times is methylene blue dye. Money is POPULAR MECHANICS treated with it and 30 leaves a tellt 1 stain on the hands of persons taking coins or bills. Washing only spreads evidence, for a stain is left on the to After one hotel 1 navel h id received peated complaints of theft from gue rooms, he arranged an electric signal the doors and, in the pockets of garment hooks. One nsn sounded and detectives ru — 1 his har : é ! ; piaced a numoper oOo! alarm up to find a man trving to free the from one of the hooks in a coat pocket INSECT YIELDS CAMPHOR In a small insect discovered in the for ests of Sumatra, an English naturalist see a possible rival of the camphor tree as e useful drug. source of th The creatu fluid which possesses t and t these secretes a milky properties of camphor, it is said, has been made that suggestion sects might be raised artificially, as ar silkworms, to produce camphor, whicl now obtained from tree MODEL GLIDER PLANE SAILED WITH RUBBER BAND Movements of a real airplane are tated bv a small glider which is shot a rubber band attached to a small sti or pencil. By cl inging the y ne making other adjustment the glider « be made to loop the Op O f] raig (he parts are assembled with rubl bands to hold them securely in place ae / / jf oe —— Launching Toy Airplane with Rubber Band, Serves as an Effective Catapult Which ——

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POPULAR MECHANICS sn 2 oe Hand-Grenade Practice during Night Maneuvers at the Presidio: Brilliant Glow of Missiles Burst Lighted a Wide Area and Helped Register Hits HAND GRENADES REGISTER HITS WITH PUFFS OF SMOKE Picturesque “blossoms” of smoke dotted he Presidio in San Francisco during re- ent hand-grenade practice by members the Thirtieth infantry. The puffs af- forded a visible record of the results and howed, according to officers, a high stand- rd of marksmanship. WORK DONE BY COAL DOUBLED WITH FRAGRANT CHEMICAL Chemists report fairly successful tests ith a white substance that has the odor of the geranium, only more powerful, in obtaining increased service from coal. The “trick” consists in using the chemical in one boiler to run an engine, while the exhaust vapor, still extremely hot, is used to raise steam from ordinary water in a second boiler. The material has been recondensed and reused repeatediy at a pressure of 200 pounds to the square inch and at a temperature of 800 degrees Fah- renheit, with but little deterioration, it is said. It is slightly heavier than water and is much less expensive than mercury, which has been used ‘na similar way. ENVELOPE POST-OFFICE SIGN AIDS TOURIST VISITORS (== Finding the 5 » = post office is an : eas\ task for ? a S| tourists passing ; throug] or visit- CVS : ing .a Michigan | fra Office resort, for a large | sidewalk sign in Stoughton Jaks Mich tm : he form of an i} envelope attracts attention as it projects from the building. It is fashioned of boards and the design of a letter has been carefully followed except that the stamp is not duplicated, to conform with the law.

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594 POPULAR () Hamilton Maxwell, Inc Sketch of Proposed Larkin Tower, to Be the Highest Building in the World PLAN HUNDRED-STORY BUILDING HIGHER THAN EIFFEL TOWER Patented methods of construction are to be used in the proposed 108-story Lar- kin tower at Eighth avenue, in Forty-second street, near New York city. A method has been devised.to connect the units of the framework so that swaying in a gale will not be greater than in other high buildings, it is believed. The struc- ture will be 1,208 feet high, topping the Woolworth building by 416 feet, the Book tower building in Detroit, Mich., by 335 feet and the Eiffel tower, for nearly forty years the highest structure in the world, by more than 200 feet. The base portion will contain eighteen stories and the tower itself ninety. Besides these, there are two stories below the street level, making 110 in all. MECHANICS SWIMMING POOLS AS ICE PONDS BRING CITY REVENUE Gregory, S. Dak., has developed an ji teresting plan for raising money and ser ing its citizens, the idea having worked so well that it has helped place the cit on a firm financial basis, out of debt. the park are two concrete basins, o1 fifty by eighty feet and the other for by eighty. In the summer time, these are used for swimming, but in the wint: they are drained, sterilized and then filled with pure city water. The ice that for: is stored in a municipal ice house and so during the summer at about half the pr: vailing price in most towns. It finds ready market for it is both clear ar of better quality than the usual natur pond ice. GRINDER SAVES USER’S EYES FROM GRIT AND DUST Several advantages are claimed for motor-driven horizontal disk grinder, compared with the vertical type or ord nary emery wheel. It is said to produce flat finish more easily and is portable dust, grit and sparks cannot injure th operator, the danger of breaking wheel is eliminated and production is increased as the worker has a proper support for the arm and can thus feed faster. The unit is especially useful for finishing small parts after the milling and other machine operations have been completed. Horizontal Disk Grinder in Operation; Sparks and Dust Fly Away from Worker’s Face

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With the “Merry Joeys” of the Tent World Only Woman Clown Tells of the Clever Tricks Which Win Laughs from the “Towners” By EARL CHAPIN MAY THE residents of Clown Alley in the men's dressing room were washing up tter the matinee. Each comedian of the tented world stood close to his fellow unsters, as he soused face and hands in id water that half filled each clown’s ilvanized-iron pail. As each face lost the last remnants of iake-up, there emerged the veteran Louis ‘lomonoin with his laughing eyes; Buck eahy, who doubles on the Roman rings nd does a roaring knockabout; Fred Les- e, Clyde O'Neil, Billy West, Steve Buck- and his brother Al; Gay Gibson, and ‘thers of the clownish clan. “Which of you fellows plays the clari- net?” I inquired. Silence fell upon the group. Its mem- bers busied themselves in hanging gro- tesque costumes on wire racks or pack- ng them in the little flat-topped. iron- sound “professional” trunks which hold such an amazing quantity of circus stuff. Then Harry La Pearl, chief of Clown Alley because he is both principal and pro ducing clown, replied mysteriously, “The clarinet fellow you're looking for will be in the cookhouse soon.” So in ten minutes Harry, looking not unlike a small-town clothing dealer as h« stepped briskly along in his neat sack suit, joined me. We were in the circus backyard, whose walls are of canvas and where one finds the dressing rooms—the women’s separated from the men’s by the “padroom,” where the fat “rosin backs,” or principal horses, and the lean jumpers and members of the equine high school are fed and bedded down. “T guess she’s in the cookhouse,” was all he said. Threading our way among guy ropes, tent pegs, wagon tongues, horses and elephants gathered at the wa tering trough, we passed the big top and 595

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596 POPULAR Harry La Pearl, with His Three-Foot Shoes; with His Wife, the Only Wom- an Clown, in Center; and Below, Mrs. La Pearl in “Merry Widow’ Costume menagerie, steered our course around the sideshow with its flapping banners depicting wild men and sword swal- lowers, sidestepped the stables now being torn down and loaded for the coming night’s railroad run into “tomorrow's town,” and thus reached the dining tent. “The flag’s still up,” Harry said with re- lief. “We've got steward keen on enforcing rules. If the flag isn’t flying from the cookhouse peak you're out of luck. The dining room is closed.” He grinned, then led me to one of twenty long board tables, with with china, glass and plated ware. He bade me sit upon a narrow, hard, blue plank at a table, and beside a fair young woman with luminous eyes. “Meet my wife,” he said. Mrs. La Pearl and I shook hands. Aiter the steak, potatoes, beans, bread, jam and coffee had been dispatched, I re- minded Harry, “You said we’d meet the a who’s covered linen and set MECHANICS fellow who plays the clarinet with the 1 of your ‘Joeys’ on the clown band wag in the street parade and in your clo band number under the big top during t}\; show. That clown was funny. Why d you introduce me?” “T have,” said Harry, gazing across coffee cup at his wife. “Loretta La Pe is the only woman cireus clown.” “So you are the ‘general,’ in green coat with golden epaulets and broad hat w a high cockade, who played the clarinet so painfully in the street parade today I demanded. She nodded. Loretta La Pearl became a clown | cause she married one seven years ago. > wanted to be with he: husband, but he to her there was abs: lutely no demand i women clowns. “Then let me mak: up as a man,and clow: with you Joeys fro: Clown Alley,” she { pleaded. And she | ¢ been at it ever since “Tt’s not a hard life, clowning for a cir- cus; not after you get used to it,” she says.

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course, an hour or so each morning on a hard springless seat on the less top of a circus wagon, in the sun Especially when the that nothing can -hurt a clown, shoot peas with airguns iin, is not so nice, boys, who think hurl peanuts at us while we are on pa- e. And now and then we have a run- iv. But nothing really happens that 1 be called serious. ‘Although we have such long parades I always have to appear a half dozen fferent times during each afternoon and ening show, I actually am on the job less in six hours a day. And, then, the vning trade, like anv other trade, is ed with tricl The first trick I learned how to save self. You see e do some knock- bout stuff and unny falls when m working on e center Well, to study to bea ‘-lown and Harry old me to fall, full length, upon the floor, I nearly broke my back, or thought [ did. But by and by I learned the trick of mak- ing my rounded stage. WV hen | began shoulders take most of the blow. Now I can fall or sprawl almost any way with- POPULAR MECHANICS 597 Loretta La Pearl, Above, in One of Her Acts; in the Center, Pete Mardo in Costume, and Below, a Typical Slapstick Scene with the Slapstick About to Be Used ou suffering the least bruise. “Vou saw. or vou thought as principal clown, slap me He didn’t, though. a trick in learning to ‘take the slap.’ you saw my husband, in the face. here's rhe slappers hand barely touches my unpro tected cheek, palms inward, a resounding while my two hands meet, right in front of me with ‘smack. Then one of my hands is raised rapidly to my face—and the ‘towners’ laugh because they think | really have been slapped. Towners al ways laugh if they think a clown is being maltreated in But the clown a bit of sleight of hand. “So is the explosive slapstick some way. “ge slap is really which all ‘| he deto nating cap in such slapsticks explodes, not clowns use at different time on the person of the clown attacked, but upon the hand of the clown who wields it I'm talking full-fledged who know their trade. now of clowns

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598 POPULAR MECHANICS “Now and then Harry joins out an ama- teur, a youth who is known in his first season as a ‘First of May.’ Such a youth has confidence, but lacks judgment. We had such a one on our show last spring. He was supposed to slap me, and he did. My cheek stung for many an hour. An- other First of May was instructed in slap- stick exercise. The slapstick, whether it has a detonating cap or is merely made to give forth sound by flapping its two parts together, is not supposed to hit its victim hard. If you'll watch an old clown work- ing in the ring, you'll see that this is so. But this particular First of May wanted so much to make good that he belabored Harry until we had to poultice him. “The second-season clowns are known as ‘Johnny Come Latelys.’ They are the sophomores of the clown school. And the chances are that if First of Mays live through their first season and become Johnny Come Latelys, they may, in time, graduate into principal or producing clowns, such as my husband is. “Harry originates’ and stages all the special clown stuff on our show. A real producing clown has to keep up with the times. When Edmund Rostand’s ‘Chan- ticleer’ was having such a vogue, Harry came out with a clownish ‘Chanticleer.’ When the ‘Merry Widow’ waltz was all the rage, Harry did his first walkaround— \ along the hippodrome track, you kno\ in an enormous Merry Widow hat. | originated the dance on shoes, the soles which are nearly three feet long, m: than a dozen years ago. “I’ve said that circus life is not hard have a lower Pullman berth which I hay: decorated with cretonne and made homelike as I can. We rarely get up unt eight each morning and we sleep well, though sometimes the engineer in movi: the circus train about jerks it a good de If the circus lot is a mile or more fro: where the circus train unloads, we brea fast downtown, but, at any rate, from ‘nin o'clock until eleven we have nothing to d but unpack our costume trunks, mend and wash, read letters and all that. Supper over at five o'clock. We haven't a thi: to do between that time and nearly eig! when we make up for the evening sho, You see, it is not had, although some lot are dusty and sometimes the rains follo us and things get pretty cold and damp After the five or six months’ circus se: son ends in October or November, M: and Mrs. La Pearl are at home in thei: comfortable six-room cottage at Hunt ington, W. Va., where you will find her making potato pancakes or turning out! roast chicken with oyster dressing, i1 which she takes due pride. While she i thus employed, her husband, in overalls The Clown Band in Action; Pick Out the Clarinet Player and You Have Found the Only Woman Clown in the Circus World, Loretta La Pearl, Whose Husband Is the Leader TW

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his shop,in the back- address,” making ” : . . e”” order kes” which aid him age” Rec At Right, Measur- . p ing the Ribbon of their “perma- Roll for Quick Estimate of —— Remain- yes or siz icks ing; the Bolt- shoes or lapsticks or Width Meter and is and wool-stuffed the Lace “Yard- POPULAR MECHANICS 599 his “Hindu dance.” Or he may be designing ( umes for the season ome. TWINS WHO LOOK ALIKE SIMILAR MENTALLY wins who look so ‘-h alike that it is hard ell them apart have er similarities besides ot appearance, ac- cording to tests conduct- | recently at Columbia | versitv, which showed ir mental processes | ‘re almost identical. | tests were given to | L I58 pairs and showed hat all sets of twins are more alike men- than brothers and sisters who are eparated by a year or more in age. Girl ins and boy twins were more alike mentally than boy-girl pairs. Sixty-three the pairs were so alike physically that they were almost indistinguishable. CAKE MODEL OF BIG BUILDING LIT BY FLOODLIGHTS Engineers took a. hand in the making of a 150-pound cake model of a ten-story building in Fresno, Calif. It was baked in twenty-one specially de- igned pans, which experts of utilities company prepared, and was lighted with 121 tiny floodlights to imitate the struc- ture after which it was modeled. The cake was four and one-half feet high and twenty-four by thirty inches in floor area. It was finally cut into 150 pieces and distrib- uted among em- DRY-GOODS METERS SAVE TIME IN TAKING INVENTORY Aids to the dry-goods, merchant have been introduced to simplify the laborious task of taking inventory. One of them, a cloth meter, gives quick and accurate count of the folds on a bo!t, while a chart, used in connection with the meter, indi- cates the yardage. Another instrument like the cloth meter determines the ap- proximate length of ribbon left on a partly used bolt. A reel for winding laces has a gauge that registers the yardage. AMERICAN-MADE IDOLS ARE OFFERED TO HINDUS A number of mid-western firms have sent a repre- sentative to India to open an office for the sale of their products. One con- cern offers to make idols and other ob- jects for the Hin- dus to be used in ployes and friends. Company Officials and the Illuminated Cake their religious rites.

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600 Sawdust Doll and Sticks ot Dynamite, Samples *of What Can Be Made from the Wood-Flour Material Prepared from Substance Formerly Wasted FROM DOLLS TO DYNAMITE IS STORY OF SAWDUST From sawdust and other mill waste a “ wood flour” has been prepared and is now being employed in the manufacture of many useful articles. Among them are inlaid linoleum, dyna- mite and dolls. Experiments are being conducted to find still other new uses for the substance. material known as MAN-EATING TIGER WHEN SHOT IS FOUND WEARING COLLAR A man-eating tiger that had taken an enormous toll of human life in India for many years was finally killed recently— and found to be wearing a collar around its neck. Rear Admiral C. M. Beadnell, who reported the incident in London, said the animal at one time apparently had belonged to a menagerie, but escaped and, with the usual fear of man overcome through close contact with peo- ple while a captive, the beast .turned killer. It was so bold that it Would at- tack an ox-cart in broad daylight, or stalk into a village and walk off with a child under the very eyes of its parents. For years it escaped poison, traps and guns, until finally the price on its head grew so great that the number of hunters became too large for even its skill to wild POPULAR MECHANICS avoid. Admiral Beadnell, who has hunted big game all over the world, also report a thrilling lion story from one of his tri to Africa. He had shot a large rhin eros, and was on his way back to ca: when four lions suddenly rose out of the tall grass less than fifty feet ahead. The admiral reached back to take the ri from his gun bearer, and when it was not placed in his hand looked around to see the native vanishing over a hill in thie rear. The lions began to advance. Bead- nell unslung his field glasses from arou: his neck, held them by the strap, a1 swinging them around his head, sudde1 shouted and started toward the lions, who promptly turned tail and fled. TABLET IN HONOR OF FRANKLIN PLACED AT FRENCH PORT The 150th anniversary of Benjamin Franklin’s arrival in France was the oc- casion of ceremonies last December the port of Auray where he landed. A tablet erected to his memory and one of the thoroughfares of the tow: has been named for him. Althoug! France was unwilling to declare open enmity against England at the time oi Franklin’s visit, the diplomat succeeded in obtaining large loans for America. was ¥ Le ¢ Oteamene 1770 ae : cemanque 4 AURAY © SAR & BENJAMIN. PRANKLIN ©}. crore om France ‘ ven cop Eravs-Uncue 9 AME nique MoseCER. to PREMIERE AL AtANCE - ~ pi ge : “20S Kha Parp ~ i 7 ih pnae Ben Franklin’s Memory Is Still Cherished in France; Tablet Erected at Port of Auray

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nin OC- POPULAR MECHANICS 601 AUTO DRIVERS’ SKILL IS TESTED BY MACHINE In the Auto Drivers’ Testing Laboratory; Traffic Pictures Are Thrown on Screen While Subject Handles Dummy Car as Though Actually Driving Driving problems that would common- ly be encountered on the road are given candidates for chauffeurs’ and drivers licenses in Leipzig, Germany, while they sit in a dummy automobile and manipu- late the controls. Close in front of the subject, is projected a motion picture of traffic in a congested district and he is required to govern his “car” as though he were actually driving it on the street. Any mistake made is registered automati- cally on the tape of a recording apparatus connected with the dummy auto. From the results, the examiners are able to con- struct a psychological picture of the sub- ject’s reactions and form a fairly accurate judgment as to his fitness. How well the candidate endured the strain is meas- ured by a separate bit of mechanism. SPLITTING GRANITE WITH AIR The expansive force of compressed air is employed in an interesting way by a granite company in the south. On a sloping hillside, composed of granite that shows no bed planes but splits readily in any direction when started, a three-inch bore is sunk about eight feet deep and the bottom is enlarged by exploding a half stick of dynamite. A small charge of powder is fired in this hole which starts a horizontal crack or cleavage. Charges increasing in size are exploded until the breakage has extended over a radius of seventy-five or a hundred feet. Then a pipe is cemented into the bore, and air is forced in under a pressure of eighty to 100 pounds. The expansion of the air extends the cleavage until it comes out at the surface of the slope. A huge sheet of granite is thus separated. FURNACE BLOWER SAVES COAL AND MAKES QUICK FIRE Operated from the lighting socket, a portable fan blower directs a strong air current through the ash door of the furnace or heater. An ad- justable, hinged unit at the end of the air tube, per- mits sending the draft where it is most needed, at the rear, middle or front of the grate. The outfit weighs but twelve pounds and can be used with- out making any changes in the furnace.

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602 POPULAR MECHANICS QUEER BUILDINGS THAT CATCH EYE IN THE WEST Replica of the Sphinx, Built for California Real-Estate Office, Attracts Attention of Passers-By, and, at Right, Cottage in a Tree Constructed by Aged Man in One Week a / aa aati oy _ = | from Prospective Buyers Obtain a Good View of Property This Lighthouse Tower on Subdivision; the Lookout Is Illuminated at Night; Castle at Right Is Real-Estate Sales- man’s Office and Has a Drawbridge and a Miniature Lake on the Carefully Landscaped Grounds a va

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IKE OF ICE SHUTS OFF WATER FOR SUBMARINE BUILDING lo facilitate submarine construction at usum, Germany, an interesting method shutting off the water has been devel- ped. Instead of using sheet piling or uilding caissons, a solid ice dike is rmed by sinking a system of pipes along he line the dike is to follow and partly tilling them with liquid air, which, when evaporating, lowers the temperature to 80 degrees Centigrade below zero. In few hours, an ice wall, nearly ten feet hick and projecting out of the water hout six and one-half inches, is formed nd can be maintained as long as liquid ir is supplied for continued evaporation, vhile the shut-off area is pumped out and until a permanent dike is built. The undertaking at Husum aims to shut off the bay by a wall nearly 5,000 feet long and will be followed by larger projects. (he method is not applicable everywhere, but lends itself particularly for regula- tion of river courses and reclamation of land, and is said to be economical. WIND BLOWS GIANT WHISTLE CUT FROM WILLOW TREE Making willow-tree whistles is a fav- orite sport in many lands, and the world’s record for size is probably held by some I:nglish boys who made a whistle ten feet high and twelve inches in diameter, and then let the wind blow it. It was constructed along the same lines as the toy article and POPULAR MECHANICS 603 In the Combination Goldfish Hospital and Home; Dis- tributing Fish among Storage Tanks LONDON SHOP IS GOLDFISH HOME AND HOSPITAL Ailing goldfish receive careful treatment at an interesting store in London where the pets are cared for when their owners are away. The proprietor has become known as the fish doctor and is said to do a brisk business as he also keeps a stock of unusual and decorative specimens. SAFETY ZONE MARKED BY POSTS TO PROTECT PASSENGERS roped high in a tree where the mouth end would receive the full blast of the Whena wind came up a few days later, it blew the whistle so loudly that it caused considerable alarm until the source was discov- ered. The whistle finally came to an unlucky end, for an exceptionally breeze. strong Lengths of steel pipe, set firmly eight feet apart in the pavement around the safety zones in Cleveland, Ohio, have found further protectors o f per- been effective as sons getting on and off the street At the entrance to the zone, there is a special bumper post, and an amber light on another post cars. strong wind tore it from its moorings. Insuring Cleveland Street-Car Passengers Extra Safety t he While Waiting; Posts around Safety Zones o oe warns the motorist cautious.

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604 POPULAR ELECTRICITY IS USED TO SOLVE CRIME MYSTERY Crime-Detecting Appara- tus Which Outwits the Mind; Young Woman’s Heartbeats and Pulse Are Visibly Recorded,to Show Changes in Response to Questions By the application of special electrical A PI | instruments, a robbery was solved in less than an hour during an interesting test in New York recently. The demonstra- tion further indicated to what extent science is now able to aid in the war against crime. Three persons in the audience were given sealed instructions from the room. In one mes- sage, the holder was required to go to the tenth floor and remove $10 from an envelope in a coat pocket. When all the subjects had returned, the instruments were adjusted and the reaction of each and sent was studied while questions were asked. By quickened heart- MECHANICS velope was asked questions bearing on the robbery, the accelerated action of his heart was immediately evident. The change in electrical resistance was made apparent by means of a moving spot of light thrown on a screen in full view of the audience. When the persons ques tioned became unduly excited, the spot In addition to amplification of the sound, the heart-measuring translates the beats into lines on a chart so that the pulsations can be detected. shot clear across the screen. instrument ELEVATOR ON BAGGAGE TRUCK PREVENTS BREAKAGE To save time handling machin- ery and crated goods, a baggage truck with an elevating platform, which can be operated by one man, simplifies the task of loading or unloading. The ele vator can be raised level with the car floor, thus saving lifting and reducing the likelihood of ‘drop- and work in heavy shipments, such as safes, beats, and by a change in the elec- trical resistance of his skin, due to an effort to conceal the truth, the “cul- prit’’ detected. The heart- beat test was made with an improved stethoscope which amplifies the sound of the heart 100,000 times. When the was easily ping the goods with consequent break- age. The operation is performed by means of a worm and the lift las a capacity of 000 pounds. The truck also has a safety handle which locks automatically in a perpendicular position and pre- vents children’ or gear I 3 “ young man who had opened the en- Safe Lifted to Level of Baggage Car on Elevator Truck for Easy Loading others from stum- bling over it. A

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eel lock, thrown in or out of gear from e front, top or rear of the truck, pre- ents the vehicle from moving when a ad is being handled. HOW THE “BIG TOP” IS MADE Much has been written of the fascinat- ng life and activity under the circus tent ut few persons give a thought to the big top” itself. The largest circus tents eigh twenty tons or so, about forty per cent in cloth and the rest rope. Instead of being extremely heavy, the material is but slightly heavier than the cloth for the pockets in men’s clothing. Some of the irger tops contain as much as nine miles f rope. Most tents do not last longer year on the average. Old ones are cut into pieces and sold to farmers as tarpaulins or to interior decorators for covering furniture while papering or painting. An investment of $10,000 to $16,000 is not unusual in a single large tent for the big circuses. than a RECORD MOTOR FOR AIRPLANE HAS EIGHTEEN CYLINDERS Experts attribute the success of France in the field of aviation not only to the skill of her flyers but to the efficient equipment her engineers employ. This is illustrated in motors for the planes. An eighteen and a twelve-cylinder type are said to hold more world’s records t Eighteen-Cylinder Motor for French Airplane, Capa- ble of Developing 700 Horsepower than any other make. The former de- velops 700 horsepower and the latter 500. POPULAR MECHANICS 605 J Delivering Shoes for Repair in Sidewalk Hopper That Is Always Open, Though Shop Is Closed SHOP THAT NEVER CLOSES HAS ‘POST-BOX “ENTRANCE” Attendants in an eastern shop leave after working hours, but the store really never closes, for shoe-repair customers can deliver shoes to be mended through an opening in a sidewalk post box. In- structions are included with the so that the menders can begin on the shoes the next morning. The proprietors declare that the plan has resulted in a marked business. bundle increase of COLD AIR PUMPED INTO HOMES AS SUBSTITUTE FOR ICE Instead of filling the ice box, residents in a Texas city simply turn a jet and a flow of frigid air emerges to preserve food and other supplies. pumped through pipes similar to gas mains fronr’a central plant, and the plan is said to be especially suited to refrig- eration in large storage rooms. The air is

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Ca 2 sages \n a See be a 6 ee ewe \ “a Where Airplanes Were a Curiosity; Rig- “+2 ging the Ship in New Guinea Wilds . Papuan Warrior in His Rattan Armor, Which Shields Him from the Arrows of His Enemies = N ~— 2 4. Prof. Matthew W. Stirl- ing, One of the Leaders of the Expedition with Two Young Papuans, and Dvyaks of Borneo Watching the Arrival of the Airplane; the Natives Were Greatly Alarmed When They Saw White Men Drop Out of the Skies

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‘Ba _— SS Soa, —_— —_ WW After the Thrill of Seeing the Plane, Native Papuans Posed with Members of the Expedition Ome Left, Dyak Chief after Bs Ride in the Plane, and Boat Maker with Odd Haircut Lifting the Plane 2board the *“‘Fomalhaut,” at Batavia, for the Journey into Jungle Wilds; the Expedition Led to Regions: Never Before Pen- etrated by White Man; the Plane Was Used for Carrying the Necessary Supplies and for Aerial Surveys a 607

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608 POPULAR MECHANICS ings. Napoleon’s private collection was arrange by Barbier, his persona librarian. The books are assembled in order! fashion in alphabetica order under large bras letters fitted upon the walls near the dull oal Here and ther: among the prevailing cases. brown bindings, a volume in red morocco, bearing an “N” with the fou crowns beneath it, distin guishes a book that had been bound especially for the emperor. The room Where Napoleon Read and Pondered; Interior of His Private Library Now Preserved in Fontainebleau Palace NAPOLEON'S LIBRARY IS SAVED BY AMERICAN MONEY Napoleon's 4,000 books and his private study have been made secure by recent ex- tensive repairs on Fontainebleau palace, where the priceless collection is housed. The work was financed by the Rockefeller foundation and was directed by Welles Bosworth, an American architect. In 1810, the books were damaged by rain en- tering through the leaky roof. At that time, Napoleon him- is about fifty feet square with three and to the rear is the narrow staircase that leads to what wa Napoleon’s private study. The public i not admitted to the library and only the president may withdraw a shelves on sides, volume. NIGHT-FLYING LANES EXTENDED FOR THE AIR MAIL Success of the air mail is as much a vic tory for scientific illumination as for any other feature of the task, experts declare pointing to the fact that, but for the well lighted landing self ordered the holes mended. In 1924, it found that the ancient oak beams had become sO worm-eaten that immediate were Was repairs required. American capital came to the rescue when the French government was unable to finance the task. The work also assures the preservation of the main palace library of more than 30,000 volumes and its rugs, furniture, fields and the bea cons that guide the pilots on their course by night regular schedules could not be main- tained, and there would be great loss of time. Extension of the air-mail ser ice has led to the in- stallation of chains of lights onthe route between Chi- cago and St. Louis and on route No. 3 from Chicago to Dallas. One of the huge bulbs for a ten-kilowatt flood- paintings and other valuable furnish- Bulb for Ten-Kilowatt Floodlight Used in Guiding the Air-Mail Pilots at Night light is shown in the illustration.

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POPULAR MECHANICS 609 COPPER BAND AS MOVIE FILM GIVES DEPTH TO SCENES One of the dreams of the movie fan and producer as well, pictures in three dimen- ons, that is, with depth as well as breadth and height, seems realized as a result of an invention of two Germans. he usual transparent film is replaced by copper band, the pictures being photo- graphed upon it and developed in such a manner that a true perspective view of the scene is produced. The “film” is perforated in the usual manner and the mechanical operation of the apparatus is the same as in the ordinary projector, As Man Talks into Tele- : ‘ His phone, a Picture of Voice Is Recorded but as the copper strip is not trans- parent, the light source is placed in front and the image thrown upon the screen is a reflected one. The finished metal strip is said to cost no more than the standard celluloid. The per- spective or plastic effect is obtained by making the ex- Diagram of the Projector Show- ing the Reflecting System, the Machine and a Strip of the Cop- per Band posures from four diagonally opposite points and reproducing them as one on the master film. It is also said that pic- tures can be shown in multi-color effects by a simple process. VIBRATION PICTURES AID DEAF AND SHOW BULLETS’ SPEED Vibrations of almost any character are recorded on an instrument developed | an eastern research worker, by which he hopes to aid the deaf, determine the speed of projectiles, measure the recoil action of guns and perform various other inter- esting and helpful tasks. In assistin the hard of hearin Tor instance, the apparatus would afford a picture « the various tone so that the subiect could e taugnt tf identifv thet b sight and thus learn to imitate them with his own voice The instrument 1 expected to aid in locating artiller) and airplane

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610 POPULAR TREES TRAINED TO FORM CHAIR WHILE GROWING Trees That Grew Up to Become a Chair; Saplings, Trained and Grafted, Formed This Seat From seeds, Wisconsin man has grown a serviceable chair which was sold recently for $4,000. When the saplings were three years old, they were gradually trained and grafted to take the form of the chair and, after ten years, all the trees but those which formed the legs were cut away. When the supports had grown stronger, they also were cut and the chair trimmed and polished. Only few alterations had to be made. twenty-eight box-elder planted eleven years ago, a CARELESS DRIVERS SENTENCED TO SAFETY SCHOOL Careless motorists in Chicago are being sentenced to attend a safety school where they are taught traffic regulations and why various ordinances have been passed, and are encouraged to ask questions to clear up any misunderstandings they may have. The plan is applied to minor violations, such as failure to stop at boulevards, pass- MECHANICS ing traffic lights, making wrong turns, etc As many as 500 persons attend a single class and the lessons are given by a com petent traffic official, The school is held each Thursday. Persons who appear more than once at the training class, as a result of a sentence, are lectured severely, and a third offense leads to a fine. Officials be lieve that the plan supplies a great need for education in proper driving, and al though it has reduced the number of cash fines, it is considered a practical influence toward greater safety. MORE ACCURATE TIME GAUGE TO AID RESEARCH For laboratory work, where the utmost accuracy is necessary in measuring the speed and duration of phenomena, the bu reau of standards has devised a time gauge which registers half-second intervals to an accuracy of within a few parts in 100,- 000. It consists chiefly of a slotted pen dulum which swings past-a point of light As it sways, the light, flashing through the opening, falls upon a sensitive surface and a tiny electric current thus generated is amplified while a moving photographic film records the instant. VACUUM CLEANER IS RUN BY FRICTION WHEEL Electricity is not needed to operate a self-generating vacuum cleaner which de velops strong suction through the move- ment of a small fan driven by a friction wheel as the cleaner is run over the rugs and carpets. This unit is said to turn at the rate of 4,000 revolutions a minute. Vacuum Cleaner Which Requires No Cords or Connections; Suc- tion Is Developed by Friction Wheel and Revolving Fan thread and dirt deeply imbedded in the fabric. It will not injure floor coverings, weighs only a few pounds and saves the bother of cords and other attachments.

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t ce rle eld re ult st he Ze to a n- it. rh pe ~<

ee Courtesy E. R. Squibb & Sons Extracting Antitoxin Serum from an Immunized Horse; a Single Animal in a Year Furnishes Enough Material to Treat from a Thousand to Fifteen Hundred Cases of Scarlet Fever How Horses Make the Best Factory for Manufacturing Scarlet-Fever Antitoxin By FREDERIC DAMRAU, M. D. WHa [l is the most effective machine for making remedies to combat hu- man infections? A horse! Back in the nineties, when antitoxin for diphtheria first came into use, the value of the horse as a factory for the making of antitoxins first became appar- ent. And today, in innumerable labora- tories, thousands of horses are being sus- tained for the sole purpose of producing curative serum. History repeats itself. Two distin- guished physicians, man and wife, set about to accomplish, in the case of scarlet fever, what German scientists had done for diphtheria twenty-five years previous- ly. They are Dr. George F. Dick and Dr. Gladys H. Dick. And again the horse was found to be the most satisfactory

machine for making the serum. It was no easy sailing for the Dicks. Only four years ago, the cause of scarlet fever was not definitely known. Of course, every- body knew that the disease must be pro- duced by some erm; but out of the several hundred described in’ medical books. each of which had already been convicted of causing one or more diseases, it was difficult to pick the one guilty of the crime of scarlet fever. The Dicks had reason to suspect a blood-dissolving, dot-shaped germ, grow- ing in chains, and they determined to put their theory to the test. A heroine in the form of a young woman, twenty-five vears old, volunteered to submit to the experi ment. She furnished the proof that scar- let fever is due to this germ by allowing 611

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612 POPULAR MECHANICS ~S Dr. George Dick and Mrs, Dick in Their Laboratory, Where They Found the Scarlet-Fever Germ and the Means of Combating It herself to be inoculated and suffering an attack of it. The next step was to determine just how the germ conducts its campaign against the human body in cases of scar- let fever. Does it attack the body’s cells directly or does it form poisons that travel around the circuit to spread de- struction wherever they may strike? Some germs, like those that cause ty- phoid, invade the entire body. The diph- theria microbe works in a different way. The germs remain localized in the throat or nose and there manufacture their poisons, called toxins, which are absorbed into the blood and travel around the body, damaging the heart, nerves, kid- neys and various other organs. The Dicks proved that the blood-dis- solving germ of scarlet fever manufac- tures a toxin just like the diphtheria microbe. When an organ is attacked by toxins, it suffers injury. But if the dam- age is not too great, it promptly sets to work to defend itself. This it does by manufacturing enormous hordes of chem- ical combinations ca- pable of destroying the toxin. These little sub- stances, the protectors of the body, are known as antitoxins. The blood of a person who has recently recov- ered from an attack of diphtheria, will render harmless a broth con- taining the powerful poison of diphtheria. In other words, the anti- toxin of diphtheria ren- ders the toxin inert. That is why antitoxin is cura- tive in the treatment of that disease. The Dicks proved the same condition of af- fairs in the case of scar- let fever. That repre- sented a great advance. It pointed the way to a specific remedy for this plague. In other words, the Dicks determined to follow in the footsteps of the pioneers who had discovered the antitoxin for diphtheria and see if the same results could be at- tained in scarlet fever. A horse was chosen to demonstrate the possibility of manufacturing an antitoxin for the cure of scarlet fever. The animal was injected under the skin with filtered broth containing the poison of the blood- dissolving germs of scarlet fever, but not the germs themselves. At first, there appeared to be but little response to the injection. Then larger doses were given. The horse became drowsy, fed poorly, had fever, and showed an inflammatory swelling at the point where the needle had been pushed into the skin. After very large doses of the toxin had been injected, as much as half a pint, the animal’s blood was tested, to see whether it was able to neutralize the toxin of scarlet fever; in other words, whether scarlet-fever antitoxin had been manu- factured. And the result represented a great triumph for the Dicks and a god- send for the thousands of children who

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POPULAR MECHANICS 613 Upper Left, Cour tesy E. R. Squibb & Sons; Others from Lederle Antitoxin Laboratories Preparing the Final Antitoxin, Upper Left; Trying It on Guinea Pigs to Check Its Purity, Right; Making a Chemical Test, Lower Left; and Supplies Waiting to Be Packed ordinarily fall victims to scarlet-fever in- fection every year. Two teaspoonfuls of the horse’s blood serum were found to contain sufficient antitoxin to neutralize an amount of the scarlet-fever poison capable of producing the symptoms of the disease in twenty grown-up men. The final step in this romantic con- quest of scarlet fever was the trial of the antitoxin in actual cases of the disease. For the purpose of analyzing the results, the Dicks classified 100 individuals suf- fering from scarlet fever. There were fifty mild cases and fifty severe ones. In the mild cases, the ordinary treatment for scarlet fever was used; in the severe ones, the antitoxin was administered. The patients with severe cases of scar let fever, who received antitoxin, fared much better than those with mild cases, who received no antitoxin. And com- plications occurred in only four of the patients who received the antitoxin, as against nineteen of those whose cases were mild and who received no antitoxin. So, the practical tests leave no doubt but that the new antitoxin for scarlet fever is a most potent, effective and entirely harmless remedy. It is only a little more than a year since these discoveries were made and the experiments that confirmed the discov- erers’ hopes were completed; but already reliable manufacturing chemists are sup- plying the scarlet-fever antitoxin.

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614 A twenty-four hour race for Diesel-en- gined automobiles has been announced to be held some time during September on the famous testing course of the In- POPULAR MECHANICS RACE TO TEST THE WORTH OF OIL-BURNING AUTOS shift mechanism or ignition system,” L. H. Morrison, secretary of the engineer- ing society, declared. “There will be more than fifty less parts in the engine; DIESELIZED AUTO BASED ON WORTHINGTON OIL ENGINE PRINCIPLE OIL INTAKE __,3 PISTON . TWO CYCLE, DOUBLE ACTING WORTHINGTON OIL ENGINE , EXHAUST we OIL INTAKE The “Tampa,”’ First Motorized Shipping-Board Vessel with Its All-American Diesel Engine, and Sketch Ex- plaining the Worthington Principle, with Designer’s Idea of Car Using It dianapolis speedway, where gasoline cars have tried out their new developments in 500-mile races for more than a decade. As a result, cars powered by heavy-oil engines, which the more optimistic en- gineers have been predicting as a develop- ment of the next five years, may be brought forward to this vear. What a Diesel-engined ‘car should be was dis- cussed at the recent annual meeting of the American Society of mechanical en: gineers, when leaders in the development of heavy-oil engines declared such auto- mobiles could be run at only twenty to forty per cent of the cost of operating a gasoline car, and likewise would cost much less to build. The fuel oil burned, costing nine cents a gallon, at present prices, should carry the automobile fifty miles, the engineers announced. “It will have no spark plugs, clutch, gear- it will be several times as powerful as a present-day car of equal size, and will run on almost any oil that will flow through a pipe.” Such a motor would be based on the Worthington two-cycle double-acting principle, which was de- veloped for the engines in the “Tampa,” first shipping-board vessel to be motor- ized. The double-acting pistons of these motors develop power on every stroke. It is that principle which the designers expect to utilize in cutting the weight of the engine per horsepower developed. German manufacturers already are build- ing Diesel motors for trucks and heavy passenger cars with a weight of twelve pounds per horsepower. @A dime, coined in 1783 and said now to be worth $300, was found recently by a New Jersey school girl.

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SEEDS TREATED WITH X-RAYS TO INCREASE YIELD By exposing seeds, bulbs and tubers to it” N-rays for a careiully measured eriod, a Russian botanist reports that he is stimulated their development, result- ¢ in stronger roots and an increased ield. He explains that the soft re of longer wavelength than the “hard” rays which have greater penetrating power. xposure to the soft emanation must be civen for an exact time, the investigator declares, and considers his discovery of the roper length of treatment an important ilvance in the process of submitting seeds to X-rays, an experiment which has been attempted for some time but without en- couraging results. It was found that light had the effect of lowering the yield from treated seeds, so that they must be kept in the dark until planting, and too long an interval between the exposure and the sowing also had a harmful effect. rays VOICE IS RECORDED ON A WIRE AND REPRODUCED FROM IT The human voice and other sounds are being recorded on a slender wire and re- produced at will in somewhat the same manner that phonograph records are pro- duced and played. The essential difference is that the wire becomes magnetized in ac- cordance with electrical impulses which it receives while the recording is being done and the reproduction of the sound is made according to like principles. The same Recording His Voice on a Wire; the Metal Filament Is Magnet- ized in Such a Way That the Vi- brations Are Registered and Can Be Reproduced at a Later Time method was worked out by Viennese in- ventors for recording radio programs on steel bands and then playing them later. POPULAR MECHANICS Front of the Chili Building in Hamburg, Germany, Showing the Trend toward the Skyscraper Style SHIP-SHAPED OFFICE BUILDING RIVALS FAMOUS “FLATIRON” Late ideas in modern architecture have been developed in the Chili building in Hamburg, Germany, where a trend to- ward the American type of skyscraper has been noticed. The structure resembles the prow of a huge ship at one corner and, in this particular, is more extreme than the famous Flatiron building in New York city. An additional feature is the application of the elevated side- walk.. The upper floors of the building have promenades on the outside, where the workers may enjoy a bit of fresh air. PLANE’S BALLOON TIRES WEIGH TWO HUNDRED POUNDS EACH Dwarfing the automobile’s equipment, balloon tires being manufactured for the huge air liners in England are seven and one-half feet in diameter and weigh nearly 200 pounds each. They are made to ease the shock in landings and can withstand a load of eighteen tons. The wheels have hubs twenty inches long and weigh nearly a quarter of a ton a piece.

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616 POPULAR MECHANICS QUEER MASKS USED IN DANGEROUS OCCUPATIONS ‘a Homemade Respirator of Cheesecloth Used by White-Lead Factory Workers, Above, and a Mask with Tissue-Paper A Curious Combination Filters, at Right of Hat and Nose Guard That Is Really a New Dust Mask Developed by the Bureau of Mines The Filter of the Res- pirator at the Right Is in the Hood, Giving a Very Large Breathing Surface Despite Its Appearance, a Pig Was Not Used as the Model } for the Mask Above, Which Uses Several Thicknesses of Woolen Felt to Protect the Wearer from Breathing Dangerous Dust While at Work |

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POPULAR MECHANICS TV ENTY-SIX-MILE-LONG CAVE HUNG WITH ICICLES oned with glistening icicles that ieved to have formed 150,000 years hen all northern Europe and Rus- re enveloped in ice, a cave twenty- les long has been found in the Ural tains. It abounds with grottoes of extrordinary beauty; the roof is a mass w crystals that reflect the colors of nbow, and there are wide corridors, bottom of which a subterranean probably flowed many years ago. t a mile from the entrance to the cav- e! a small lake, near which were found il objects dating from the time of ‘ersian King Cyrus, and military for- tions probably built during the four- th century were unearthed near by. SOUNDS ARE RECORDED ON FILM AND REPRODUCED AT ONCE Records of the human voice and other nds are made on film in such a way that are fit for immediate reproduction in apparatus demonstrated recently in nee. The chief novelty of the instru- nt lies in the method by which the lines le by the recording needle are “fixed” the film. This is done with the aid of special liquids, held in containers small outlets, one liquid being dis- uted immediately in front of the needle | the other close behind it. The first tid flows upon the film in a narrow band makes the ma- 617 r ( 1 pana » ‘hh | | . Alarm Fence on Union Pacific Railroad, Which Sets Signal When Rock Slides Strike It GUARD RAILWAY FROM SLIDES WITH ELECTRIC FENCE Along a stretch of line where rock slides have caused wrecks in the past, the Union Pacific railroad has installed an electric fence which is intended to give automatic warning when slides occur and thus prevent accidents. When rocks fall down and roll toward the track, they press against the slack wire of the fence, this action, in turn, pulling a switch on ial softer so that vibrations may registered more fectly. The other uid cleans and ixes” the tiny The film ies so quickly, ac- rding to reports, it it can be rolled a spool, which is rt of the appa- ratus, and thus is idy for the re- roduction of the unds immediately rooves. the series of large posts set at 800-foot in- tervals. This switch operates the block signal and also af- fects the safety con- nearest of a trol in the engine, so that trains can be stopped. The fence is constructed of hog wire and the staples are not driven all the in,so that the strands will have way Courtesy L’LIlustration iterthey have been ecorded. Recording the Voice on Film for Immediate Reproduc- tion; Liquid That Fixes Grooves Makes This Possible sufficient slack to operate the signal switch.

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eee enge e Mohammed, a Hindu Magician Imported by Thurston, Improves on the Basket Trick by Apparently Actually Stabbing the Boy HERE are magicians in India—thou- sands of them—and they present cer- tain mysteries which are baffling to the untrained observer. To a magician, how- ever, their methods are simple, and the tricks they perform are far inferior to the illusions exhibited by American conjurers. The magicians of India are not miracle workers. Their tricks are easily detected by an expert, yet their magic is a real art. The present generation of fakirs show tricks which have been passed down to them by their fathers. Many of the appliances used are of crude construc- tion and this adds to their effectiveness, as they do not excite suspicion. The “Mango Tree” is one of the most 618 \ lying about, and he uses one of \ these to drape about the poles, so By HOWARD THURSTON celebrated performances of Indian ma I have heard tales of mango trees which grew from tiny roots to ten feet high be- fore the eyes of the spectators, but w! I have seen the trick performed doze: of times, never did the tree exceed three feet in height. That, in itself, would rather miraculous if the tree developed in full view, but actually the trick is done under cover. The fakir first takes three short p and makes a tripod about four feet high. He has a number of cloths that a miniature tepee is form: In the center of this is a sm flowerpot filled with earth in which the magician plants a mango seed. He now plays some weird music on a flageo- let and then removes th cloth from the little tent The mango seed h » grown toa tiny sprig. |! cloth is replaced, ar when it is removed agai! the sprig has grown tal! This procedure is repeat: until finally a two three-foot “tree” is developed. Under t! loose cloths which are on the ground, t! fakir has hidden branches of a man; tree. These he picks up under the larg cloth each time he forms the tent. 1! tree is merely a branch from a lat mango tree, and it is also concealed u derneath a cloth close by, with its ‘es branches folded together. The secrets of many good tricks quite simple; it is the method of pe formance that creates the mystery. 1 it is with the smaller tricks of the Hindu fakirs. They present their tricks wit an air of mystery which causes the spe tators to look for some complex so! tion, for example, the “Bowl of Rice

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A magician has a “lota,” a bowl with ng sides, and fills it to the brim rice. He takes a knife and inserts lade into the rice, until the knife is d to the hilt. Then he calmly lifts indle of the knife, and lo! up comes bowl. The fakir swings the knife nd his head, defying the law of grav- The explanation is simple. When knife is inserted, the rice is pressed the bulging sides of the bowl, and blade is gripped so firmly that the e affair can be lifted at once. When igician wishes to remove the knife, ives the blade a twist. ne of the best tricks seen in India is “Disappearing Bowl.” It ‘is per- ed by only a few magicians in the ras presidency. A large,..earthen about eighteen inches in diameter twelve inches high, is filled with rice. performer covers the bowl with a and jumps upon it. The bowl and disappear completely. Then the ician calls attention to a tree behind spectators, and there is the bowl of resting securely in the branches. he original bowl is merely a collaps- wire frame, covered with a soft clay, h is very thin; but, being covered a virnish, it looks like an ordinary jardiniere. Just below the opening e bowl is a tray containing enough to make the jar appear filled. The ician takes two small cloths and holds m together to look like one. He lays m on the ground and puts the bowl n them. Then he covers the bowl h a larger cloth. During this action, knocks the soft clay from the bowl, the wire frame remains upright. en the magician jumps upon the cloth, frame collapses, and it seems as An “Indian Mystery” Which No Indian Has Ever Ac- tually Produced Is Now Done on the American Stage though the bowl had magically disap- peared. In removing the large cloth, the magician takes away the uppermost of the two smaller cloths. Thus the re- mains of the bowl are disposed of. Be- fore the spectators have recovered from their surprise, the fakir points dramati- cally to the tree, where his confederate has quietly placed a solid bow! filled with rice. The “Spinning Shell” is a novel effect produced by Hindu magicians. A fine straw is passed for examination and is planted in a piece of clay, so that it stands erect. Then the fakir balances a small shell on the straw and pours water on the latter. The balanced shell begins to revolve and keeps on spinning rapidly for a short time. The trick lies in the straw. The magician, upon receiving the ex- 619

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POPULAR MECHANICS allowing only the earthenware cylinder to appear. More fuel is added, and a great flame bursts forth. The bo, screams for help, but the magician calm] increases the fire. I witnessed this mys- tery while in India, and learned the se cret. There is a small shoulder inside the cylinder. When the fakir puts in the paper, he drops in a round flat piece of iron forming a partition which keeps the fire from the boy’s head. The minor tricks of the Hindu con- jurers are charming in their simplicity The “Shooting Arrow” is a typical ex ample. The magician has a wooden im age, which holds a bow and arrow. At a word of command, the image shoots the arrow and hits a target six feet away. | have seen the arrow hit the mark at a dis- tance of fifteen feet. The left arm of the image is fixed, and the bow is held in left hand. The arroy placed in the bow, th string being fastened ir One of the Standbys of the Indian Fakirs, the Man on the Bed of Spikes, as It Is Produced Nightly in the Theater amined straw, substitutes a similar straw which is identical in appearance. The second straw, however, has been twisted and dried. Consequently, when water is applied, the straw swells and untwists, causing the shell to revolve. I recently heard of a traveler, returned from India, who described a most won- derful trick wherein a fire kindled upon a boy’s head. The details are as follows: The boy is placed in a kneeling and an earthen cylinder, six inches in diameter, is set upon his head. The cylinder is open at both ends. The fakir fills the tube with paper, pieces of wood and rags, then he pours on a quan- tity of oil, and sets fire to the contents. A cloth is tied around the boy’s head, was pesition, a notch on the side of the arrow. The heavy end of the arrow i pressed into a hole the right side of the im age. The hole contains adhesive wax, and aiter the arrow has pressed into it, eight or ten seconds will before the force of the bow will release the row and shoot it to the The magician watches the actio b een elapse mark. of the arrow as it is gradually released, and, at the right moment, commands the image to let it go. The street entertainers of India per form many interesting and varied feats I witnessed one of these men who plung: boldly into a tub of boiling water, a1 remained there for a minute or tv Then he emerged, uninjured by the | water. The secret lay in the fact tl the tub was quite deep, and that it h previously been partly filled with c water. Then kettles of boiling were poured in while the crowd w gathering. The performer plunged quic! ly through the upper laver of hot wat and lay in the cool water beneath. H watel

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POPULAR MECHANICS Above, the Mango-Tree Trick as Produced by a Fakir in Calcutta, and Below, the Live Burial Improved by Modern Magicians Who Use Glass Caskets and Water Tanks to Keep the Man Visible

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POPULAR MECHANICS kicked about and caused the hot water to mix with the cold. This reduced the temperature so that he could come out at his leisure. I had heard many marvelous stories of the celebrated Indian “Rope Trick,” sup- posedly the greatest of all mysteries. Each description bordered on the miraculous; every story involved a master fakir, who took a coil of tossed it into the air and caused it to remain there, sus- pended. In some accounts, the end of the rope was said to have gone out of sight. Then a boy was supposed to have climbed the rope and disappeared, fol- lowed by the fakir, who also vanished. In the only trick of the kind I saw, the fakir took a coil of rope and tossed it in the air, where it remained rigid like a pole, some six feet inlength. He balanced the rope for a moment, then dropped it, ind it immediately coiled itself when it struck the ground. The rope, I soon learned, contained a pliable wire, which made it temporarily rigid As soon as the rope struck the ground, the impact caused it to coil, and it appeared to be an ordinary piece of rope. I offered a reward of 5,000 rupees to any fakir who could perform the trick of the boy’s disappearance, but the re- ward was never claimed. rope, Alleged explanations have been gi of how the trick could be performed, they are generally unsatisfactory and practicable.. It has been suggested thia the effect was created by hypnotic powers of the yogi. That might be possible only: one witness were present, but cases where several persons are said have witnessed the trick, the theory can not readily be accepted. Students hypnotism have declared that “group hypnotism” is an impossibility. POISON DUST KILLS MOSQUITO WITHOUT HURTING FISH Spreading fine dust containing poiso: over marshes and ponds to kill the mos quito larve has been effective in many sections, but an objection to the method is that it is injurious to fish and other animal life as well as destructive to vege tation. This drawback is said to have been eliminated in a new poison dust in troduced in France. While it is deadly to the mosquito larve, it is said not to injure fish or warm-blooded animals nor damage aquatic plants. It is a formaldehyde co: pound mixed into an extremely fine po der that can be driven by the wind, and is most satisfactorily applied with sand. The cost is about eight cents per acre. > a Just After the Seed Has “‘Sprouted,’”’ One of the Steps in the Mango-Tree Trick; the Picture Shows the Mul- titude of Draperies Used to Hide the Various-Sized Plants until Needed

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POPULAR MECHANICS CUSTS DEFY HEAVY GUNFIRE LONG TWENTY-MILE LINE nt locusts have been invading the yside in India, three different swarms descended upon territory in the iy presidency. One “army” was miles long and thirty yards wide. the insects had settled, heavy gun- as directed upon them, but did lodge them, and several fertile tracts levastated. Another swarm was five long and half a mile wide. BOTH TUBES AND BATTERIES ELIMINATED IN SET nting for a new method of changing rical current from alternating to di- Dr. Palmer H. Craig, of Mercer uni- tv, Macon, Ga., has accidentally stum- on a discovery that, he claims, makes sible to eliminate both tubes and ries from radio, while retaining the ency and power of an eight-tube re- The Craig discovery, which bears relation to any principle applied in sets, involves the use of a pile of uth plates, protected from atmos- ic corrosion by a coat of sulphur, and a pick-up coil of insulated wire wound ind them. In action, the pick-up coil nds to the radio signal, and the wave, ng through it, sets up an electrical t in the pile of plates, which, according Craig, may be used either as a de- ‘or as an am- The appa- requires no ent outside that he radio waves ts operation. igh laboratory eriments indi- that the device, n amplifier, is times as sensi- as an eight- e receiver, while even better as letector. In ad- nto being more itive than tube , it eliminates h of the distor- in such sets. Dr. Craig with One of His Bismuth-Plate Radio De- Bookcases and Magazine Basket Assembled from Ready- itted Pieces and Decorated at Home READY-TO-FIT FURNITURE ADDS FUN TO HOME DECORATING Finding the right object to complete a scheme of room decoration is not always easy, since it is often impossible to obtain the exact color desired or a piece of the proper size. To aid the person who likes to be his own decorator, articles of fur- niture are available which can be easily put together in a few minutes and are of plain wood so that any scheme of decorating may be followed. A con- venient bookcase and magazine basket have broad sides suited to paint- ing by hand or be- ing decorated with patterns cut from paper and varnished over. In order to still further facili- tate the assembly, grooves are already made in the units so that the shelves and sides can be fitted tectors, Weighing Less Than Half a Pound together.

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POPULAR MECHANICS ie Where School Is Far from Dull; an Outdoor Trades Class in Blacksmithing; with Paper Models and a Willing Pupil as the “Horse,” the Teacher Explains Important Points to Eager Listeners TRADE TAUGHT BY BLACKBOARD AND PAPER MODELS Young boys attending a trade school in Germany, receive interesting lessons in horseshoeing and other crafts from a series of blackboard lectures. The pupils are too small to do the actual work them- selves, but they become familiar with the necessary steps by watching the process illustrated with models and drawings on the board. The figures are quickly ad- justed to illustrate the correct positions. In one of the classes, a pupil poses as the horse, to make the lesson more graphic. PASTURE PLANTS IN STRUGGLE FOR SURVIVAL Pasture plants are in continual war to see which will prove fittest and survive, according to Dr. Herbert C. Hanson, as- sociate professor of botany at Colorado agricultural Timothy, alsike clover white clover cannot withstand the competition of orchard grass and red clover and will be crowded out if their enemies are not held in check, he has found. At the 7 college. and red-top, same time, how- ever, Kentucky bluegrass, working wu the shelter of the other plants and tending its subterranean foothold ut their roots, eventually will drive out victors. Smooth brome grass and m ow fescue often hold their cattle are barred. own SELF-THAWING AUTO RADIATOR REDUCES MOTOR ILLS For quick thawing, an auto radiato so arranged that when the water reac! the steaming point in the engine, and steam p through sm holes in the ov flow pipe, start circewlat! throughout radiator. The« is of honeyco design not lik to burst fri freezing, there is a strip over t perforated overflow pipe to prevent draft through one column of air flues.

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POPULAR MECHANIC RULES FOR SAFE AIR TRAVEL ISSUED BY GOVERNMENT ‘ommercial aircraft engaged in carry- passengers or merchandise across te or territorial lines must. be regis- ed and licensed under regulations issued the first step toward active ental supervision of private aviation. vy aircraft flying across a state line, either on a commercial trip or to conduct commercial flying in another state, is juired to carry the government license imber, just as an automobile does. The reraft, however, must first pass irthiness tests to show that it is safe filving. Other airplanes, not oper- ted in traffic requiring licensing, are to registered and the number al- tted to them painted on the side. Pilots’ mechanics’ for commercial rafic also are to be issued by the gov- nment. Although the rules were effec- e the first of the vear, they will not be gidly enforced until July 1. govern- air- carry licenses SKI RUNNERS PRACTICE INDOORS ON CHEMICAL SNOW Slopes covered with chemical snow a London department re so that ski runners could practice demonstrate the essentials of the The realism of the ‘ene was increased by evergreen trees. ere arranged in port to beginners. © P. & A. Fortune Cage at Spanish Lottery; Tickets Are Placed in This Huge Steel Ball for Drawing PRIZES IN BIG LOTTERY TOTAL MILLIONS OF DOLLARS Holders of lucky tickets at the annual Christmas lottery in Madrid win fortunes, for the total prizes amount to several mil lion dollars. The tickets are placed in a special steel ball from which the winners are drawn. VEST POCKET MOVIE PROJECTOR USES FLASHLIGHT BATTERY

very man_ his motion- picture own show. This promises to become the result of a Swiss engineer’s de- velopment of a a realitv as tiny movie projector, not much larger than a cig- aret case and using an ordinary light illumination. If this fails, it is that the can be adapted to use sunlight. The pictures can be dis- pock et flash for said machine played on a wall or any other convenient and, reports, and sur- face according to

are clear

Depicting an Outdoor Sport in London Department Store; Ski Practice on a Slope Covered with Chemical Snow steady. <A _ special type of small film is used

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Nena evdlete in 43: Mak in Morehouse’s Comet, One of the Wanderers of the Sky Which Occasionally Flash across our Heavens and Then Disappear among the Distant Worlds Far Out in Limitless Space | OW would you like to live on an earth that had eight ing around overhead? moons wheel- Some day one of the neighbors in our universe—Jupiter—may support a race of people who will experience that unusual novelty. Jupiter, biggest of all the sun’s planets, is now a world in the making and represents today what our earth was untold millions of years ago, just as our long-dead moon what this globe may be at some far distant date. The eight which the earth is one, and the hundreds of smaller 7 SHows big planets, of ones, all revolving about the sun, form one of the most interesting groups in the heavens. Once there were nine planets, but at some time in the distant past one blew itself into thousands of pieces, and r trundling along left a lot of little worlds The discovery of that long- in its place. lost accident, that probably occurred«ages before the first man appeared on earth, is one of the most fascinating stories as- tronomy has ever produced. Johann Ebert Bode, who died in 1826, that discovered the sun’s satellites eight €26 were divided in two groups, four littl ones, our earth, Mercury, Venus and Mar then a long gap, followed by four bi planets, Jupiter, Saturn, Uranus and Ne; tune. He wrote down their distanc: from the sun and was struck by the fa that the mileage seemed to some mathematical ratio. servation, he evolved increase From that ol 30de’s law, whic! says that if you add four to each figur: in the series zero, three, six, twelve, twe ty-four, forty-eight, ninety-six, etc., th: result will represent the respective di: tances, in millions of miles, of each planet from the sun. But after twenty-four, which represent Mars, there was a gap where the pianet at forty-eight should have been. So as tronomers decided that there must be small and undiscovered planet there, and set about finding it. Pretty they did, but the elation had hardly died whet somebody found another planet in the same place, and then another and another until now more than 600 little ones have been listed, and the list is growing at the soon rate of about thirty a year. The answet

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POPULAR MECHANICS 627 THE LUNAR ALPS ILLUMINATED BY THE EARTH \» a N Courtesy Illustrated London News Plaster Model Showing Our Earth as It Would Appear from a Valley among the Alp Mountains of the Moon; for Lack of Air and Water to Errode Them, the Lunar Hills Remain as Rough as When Made

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628 POPULAR Frequently, While Astronomers Photo- graph the Distant Stars, a Meteor, Enter- ing the Earth’s Atmosphere, Burns Up, Making a Straight Streak across the Plate Some Meteors Are So Large That Parts Survive to Reach the Earth; Above, a Fragment from Canyon Diablo, Arizona; It Is Almost Pure Iron German Scientists Are Interested in a New Theory That Our Earth May Have a Lu- minous Ring like Saturn’s, an Idea That Explains the Ghostly Zodiac Light MECHANICS was that a big planet had broken up i: innumerable small fragments, each which continued to revolve around sun in the neighborhood of their pare old orbit. If Jupiter, at some distant date, beco: inhabited, the possession of eight mox will not be the only distinction its peo; can boast, for their years will be as lo: as nearly twelve of ours—4.332.58 day be exact. Jupiter is so much farther ay from the sun, and its orbit so much big than the earth’s, that it takes it correspo ingly longer to complete a round trij The years grow progressively longer a1 the temperature progressively colder t farther you get away from the sun. there is any place in our universe for | man life to exist today, outside the eart Venus or Mars would come nearest to it the one merely being too hot and the ot! too cold to meet our ideas. Mars is neat 142,000,000 miles from the sun, compart with our 93,000,000, and the result is average temperature of ninety below ze: at night, with daily changes to about sixt above. The average temperature of Ven: is 165 degrees, because it is nearer the su Once you pass Mars on the outward tr from the sun, the distances become tru immense. Jupiter, the first big planet past the gap where the ninth one once was nearly 484,000,000 miles away, and has average temperature of 305 degrees belo zero, and that’s the chief reason why. the: may never be people there to enjoy t! bright moonlight under its eight moor Jupiter, though, with a diameter near! eleven times that of our earth, rests secure with the record of being the biggest of t] planets. Saturn, the planet with the que: rings and the ten moons, is almost as bi Uranus is a medium-sized fellow th: would only require four or five of ou earths to span, and at the outer edge Neptune, a mere 29,827 miles in diamet« temperature 446 degrees below zero and a year of 60,187.65 days. In othe words, it would take the combined life times of two people over 82 earth-year old to live one year on Neptune! Our moon, being so close to us, is the best-known object in the sky, and, as has no vapor to hide its features, the stud) of its surface has given an accurate ide of what the eventual fate of all celestia ~_

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POPULAR MECHANICS 629

‘he Crater Theovhilus on the Moon Is the Central Depression; the Vast Hole Is 18,000 Feet Deep, and the Central Mountain, Which Casts the Black Shadow, Stands 10,000 Feet High inderers may be. The most curious because it may possibly harbor living crea iture of the moon is the way its surface tures, and the other because of its size, be pitted with giant craters, many of them cause it is a world in the making whicl iles across and often 20,000 feet or more can be studied to learn what our own earth depth. <A lofty wall of earth and rock once was like, and because, next to Venus hrown up around the edge adds to the it is normally the most brilliant of all the epth of the valleys, which sometimes have _ planets, easily visible to the naked eve their center a mountain nearly as high Mars is a dving planet. growing colder the surrounding rim. Scientists have and colder, until some dav it may be ng believed that the craters are proba- dead and lifeless as our moon. The tele- the marks of some long-ago bombard- — scope shows Jupiter as a rapidly rotating ent of the moon by huge meteors. Mil- globe of gases and vapors. There can be ons of meteors every year come within no thought of life, for a surface, in the he earth’s attraction, but comparatively — sense of a solid crust like that of the earth actually strike. Traveling at tre- does not exist. It is believed to be a vast endous velocity, they are heated to in- semifluid core surrounded by dense vapor indescence by friction with the air as which in billions of vears may evolve into oon as they enter it, and are burned up, a solid planet a rule, before they can reach the earth. Some idea of the comparative size of the (hey are familiar as “falling stars.” But two, Jupiter and Mars, is gained from the vhen a meteor gets too’ near the moon _ fact that one of Jupiter's eight moons ind is drawn to it, there is no atmosphere Ganymede, is almost as big as the red o burn it up, so the mass strikes the moon planet. From Jupiter’s great bulk some vith full force. 1,300 worlds the size of our earth could be Mars and Jupiter, of all the planets, hold) made. Four of its satellites equal or sur- the most interest for the earth—the one pass our own moon in size. ‘

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630 POPULAR MECHANICS The “Man in the Moon,” When Examined at Close Range, Becomes Moun- tains, Craters and Plains, Erroneously Named “Seas” One of the curious features of Jupiter, as odd as Saturn’s rings or Mars’ canals, are the belts, light and dark and many in number, that lie parallel to its equator and seem to be formed of denser vapors than the rest. Two semi-permanent markings appeared on the planet long ago, and have been carefully watched for years. One is called the Great Red Spot and the other the South Tropical Disturbance. The red spot was an oval formation 30,000 miles in length and 7,000 miles wide, first observed in 1871. At first a pale pink, it soon deep- ened to brick-red, then faded to pink again and gradually almost disappeared, leaving an oval white notch. It drifted around like other cloud formations, but seemed to offer an obstacle to smaller disturb- ances, turning them aside like an island in the sea. The South Tropical Disturbance ap- peared within the last twenty years, grew to four times the size of the red spot, and appears as a dark area terminating in bright, white loops at either end. Some- times the two areas come in conjunction, and then the latter disappears for a time, only to form again. Some scientists be- lieve the two spots m the first efforts of t planet to form a s crust, and others h: the idea they may p tend the birth of other satellite, whi Jupiter may be tryi: to expel from its swir ing mass. The story of th changes, reflecting they do our own ori and the observation the moon as a long-de world, give the beg ning and the end of « istence, with our ear midway between t! two extremes. Fri them it may be possil to learn how we ori inated, and how we | nally may disappear. Yet science is far fro satisfied by the know! edge that has bee learned from the moo: There is still the problem of the crate: to be solved, the problem of the va sealike plains, and the mystery of tl long white lines that radiate for hundred of miles from Tycho. They look lil mighty ice cracks, but, lacking water, ther: could be no ice on the moon, so some othe: explanation must be found. - = Lo pment - Sete, of Pinte ee Sh cee : Jf "Se tae” eis : om \ . X ee ell Our Earth Is a Tiny Thing Compared with Jupiter Also a Satellite of the Sun PC

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POPULAR MECHANICS 631 POLICE LABORATORY ON WHEELS TO CURB CRIME German Police Squad with Traveling Laboratory at the Scene of a Crime; besides the Camera, the Outfit Includes Chemicals for Making Analyses, Microscopes and Other Equipment Enabling detectives to obtain evidence resh from the scene of a crime, an auto, equipped as a laboratory, has proved of aid in Germany. It searchlight, camera, collapsible table and chairs, med- ‘al cabinet and other apparatus. Arrived it the spot, the police can set up their equipment, take photographs, make meas- urements and obtain other data for com- carries a plete analysis while on the scene, without making repeated trips back to head- quarters with consequent loss of time. SLIDING BOX FOR SMALL AUTO GIVES TRUCK SERVICE Small coupes or roadsters are quickly converted into serviceable tools and other articles, ] carriers for packages, vy means of a slid- ing box which can be pulled out at the rear and then pushedinand con- cealed when not in use. It is strongly made of steel, slides on a sleeve frame capable of holding a heavy load, and when opened to extreme length, is sixty inches long with a width of thirty-three inches. To install the box, it is only necessary to re- move the rear lower-deck panel and fasten the carrying bolts fender and the flooring on either side. frame to HUGE CONCRETE MIXER RESULT OF STRICT STATE LAW Out of the provision in the law of a southern state requiring that concrete be stirred a minute and a half before it can be poured into road forms, has developed a huge mixer, said to be in the world. one of the largest In most states, the mixture can be poured after only : stirring. one minute of Because of the extra time re- quired, the mammoth apparatus was de- veloped to make up for loss that would have been suffered with ordinary equip- ment. The outfit is practically a double mixer, consisting ot two engines, two two booms and buckets and two intake hoppers. drums, It travels on a single pair ot treads. Three cranes are required to supply it with chassis on one crawler materials as well as twelve seven-ton and four-ton 140 narrow-gauge cars. and It dumps thirty- two cubic feet of concrete on the roadbed every minute. During the building sea- son in 1926, thirty miles of eighteen-foot pavement were laid with it. one gasoline locomotives

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632 POPULAR MECHANICS FELLING BLAST FURNACE TESTS ENGINEERING SKILL ———_ Much engineering in the removal skill involved of an obsolete blast fur- nace at the Pittsburgh plant of the Amer- ican Steel and Wire company. was The fur- Where a Locomotive Aided Dynamite in Wrec} ing Old Blast Furnace; the Engine, Attache with Guy Ropes, Pulled as Explosive Was Fire to Keep Structure from Falling in Wrong JPire tion on Other Buildings Courtesy Explosive Engin nace was 108 feet high and had a max mum diameter of thirty-five feet. On: problem was to make sure that the tower ing structure would fall in the right di rection, away from other buildings nea at hand. This was solved by using gu attached to the top and tightened by a slowly moving yard locomotive, pull ing in the direction of the desired fall at the moment of the discharge of the dyn: mite cartridges used for blasting the structure. This plan caused the tower to fall exactly as desired. The explosive were blanketed by bags of sand. ropes, SUPER-OYSTER SOLVES PROBLEM OF IMPROVING ITS RACE How scientists have finally solved the age-old problem of mating the oyster in captivity, rearing its young and, by selec- tive breeding, improving the racial strain is one of the latest triumphs of the mod- ern laboratory that promises to add mil- lions of dollars to the income of the Atlantic coast states. Dr. William F. Wells, of the New York State conserva- tion commission, solved the problem which had perplexed scientists for gen- erations. The trouble had been that the oyster eggs were sO small that they passed through the filters used to purify the water in which they were kept, and if the water was not purified, they died. Dr. Wells found the solution in putting the eggs into a centrifuge built like an ordi nary cream separator. The eggs vere thrown outward and adhered to the sides of the machine, while the stale water wa drawn off and fresh water added each day. In this way the eggs were hatched and young oysters grown in captivity. In seeking crosses to improve the strain D1 Wells developed a breed of oysters with out the anchor by attach oysters which they r¢ ck. usually themselves to some Such occur as freaks in nature and

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POPULAR MECHANICS n die, but by raising them for a vear his ponds before throwing them into sea, he obtained oysters that were e to shift for themselves and grow to turity. Unlike the usual oyster, whose is misshapen and gnarled from con- ming itself to the cleft of rock in ich it grows, the new type oysters have :metrical shells, regularly marked. PLANT STEAM SIGNAL WHISTLE ELECTRICALLY CONTROLLED lo summon employes of a refinery nt to the telephone, an- electrically erated steam whistle sounds long and rt blasts in a code, a different signal ing given for each man. The impulses verning the whistle originate in a ll telephone-type switchboard which connected to a magnetic switch. The vcnal is repeated continuously until the rson summoned reports through the itchboard. In spite of changes in tem- erature and storms, the system has func- oned efficiently, according to reports, e valve having been operated more than 1.500.000 times since it was installed about vear and a halt ago. STONES FROM ALL THE STATES IN MEMORIAL FOUNTAIN Legion posts in every state of the union, nd several abroad, sent stones for the onstruction of a memorial fountain to allen war heroes at Mt. Morris, Ill. In 250 were obtained and built into the Using Rouge Stick from Tidy Package; Right Quan- tity Is More Easily Applied SANITARY LIPSTICK IN PACKAGE LATEST BEAUTY AID Individual lipsticks, held in a paper car- rier like a match package, have been in- troduced for the woman who is interested in absolute cleanliness as well as beauty. There is enough rouge on each stick for a single application, after which it may be thrown away. The package is con- veniently carried in the handbag. LEATHER FROM THE SEA There are a duce poses. that many number of fish pro- serviceable leather for pur- The shark leather of a beautiful gray, or blue color and has the appearance of the finest-grained material. It is tough but easy to work. In respects, it is said vields some to be superior hides. 1 tougn lacing to ordinary furnish a used for Sturgeons often together. leather belt In bygone days, shoes and gloves were manufactured from the skin of the cod, and the same use is being made of the skin of other Tributes from Every State and Several Countries Abroad Are In- cluded in This American-Legion Fountain of Many Stones memorial by former service men. Each tone has the name of the donor engraved upon it. fishes in a number of places in Europe today. Eelskin is em- ployed for bookbindings and for whip braiding. The garfish can be polished until it resembles ivory and is utilized skin of the in making jewel cases, etc.

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634 POPULAR MECHANICS MOORISH ARCHITECTURE USED IN MEXICAN CHURCH S Fe! a + a - - ee on ge a — ame Shed fo a ao ae Black-and-White Tile Work with Deep Window Embrasures, Reminiscent of the Moorish Palaces of Old Spain Set Off the Carved Front of the Sanctuary of Ocotlan, Tlaxcala, Mexico

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POPULAR MECHANICS ‘ATHODE RAYS DRAW RUBBER FROM LEAVES OF PLANT Discovery of a powerful cathode ray by W. D. Coolidge, of the General Elec- c company, almost on e day of the announcement, by the iestion, “What is it for?” An swer to the query is already suggested the result ent with the hev were was followed good of an interesting experi- rays on rubber leaves. directed from a distance of bout an inch upon a leaf of a rubber int. Within a few seconds after the mbardment of the high-speed electrons uing from the tube, there was a marked ow of latex, or sap. This has inspired e vision of a rubber plantation with a ize of poles, wires and tubes, the sap eing “milked” from the leaves instead { gathered from cuttings in the trunks, ; is now the practice. While authorities » not that the ray seriously ireatens to change the rubber-harvest- ng methods of the present, they do an- cipate that it may have an important irt to play in chemical and other exper- ments on rubber, particularly in vulcani- ition. The rays already are known to possess properties that have peculiar ef- ects on certain gases. believe CLOCK WITH TEN HANDS TELLS TIME IN ALL LANDS Travelers. are In the “China” Closet of a Motion-Picture Studio; Storing the Plaster of Paris Crockery CROCKERY IN MOVIES IS MADE ONLY TO BE BROKEN When the breaks a dish everyone movie comedian | over the villain’s head, knows that the “china” is a clever imi- tation of the real article, but few persons realize thin and fragile the crockery: is. Made of plaster of and painted to resemble genuine pieces, the vases, bottles and other things range ae how Take paris from an eighth to one-sixty-fourth of an inch in thickness. pared the difficulty of making time calculations at one of the railway sta- tions in Berlin, as the big clock there has ten hands hich show the correct time for is many places throughout the world. The dial is divided into the twenty-four hours for the day and night together, and the hands are marked with the names of the places This “break-away” stuff is kept in large quantities 1 almost all the much that traction dios, and it is so flimsy a small all that is m:; reaches the without dam: It is most used wit] pertect tv. the onlv dan- ger being that oc casionally the base of a piece will be- come heavy enough to register more shocl serious for which they tell the time. World Clock in Berlin Railway Station; a Glance at ial Shows Time in Ten Cities is swung with hcient torce

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POPULAR MECHANICS C. E. Mirguet be- side Giant Flipper of a Whale Pieced Together for Dis- play as a Museum Specimen ARTIST BUILDS HUGE WHALES OF BONE AND PLASTER Fashioning a whale as big as‘a freight car, or modeling other creatures almost as large, is all in the vear’s work for G EK. Mirguet, a taxidermist at the national museum. For more than thirty years he has made a specialty of constructing and mounting, in lifelike manner, jungle and sea creatures for museum cases. FROZEN ORANGES DETECTED IN TROUGH OF WATER Telling a frozen orange or lemon from a good one is a difficult task, for as the fruit does not fall to the ground.after being nipped, there is little or no change on the surface unless the freezing has been very severe, and testing by cutting, of course, ruins it. To simplify the task and to prevent shipping frozen oranges and lemons, a grower devised a “detec- tive” in the form of a long, deep trough filled about two-thirds full of water, which is allowed to flow slowly toward one end. The fruit to be tested are dropped, one at a time, from a chute into the water. Any frost-bitten ones, being lighter than the sound fruit, bob up more quickly and are caught on screens arranged horizon tally in the trough below the water line The good fruit sink farther, rise more slowly and are caught by other screens In this way the unfit product is removed and the remainder is graded. LOCOMOTIVE WHISTLES COSTLY At least $8,000,000 is spent yearly by the railways of the United States in blow ing the locomotive whistles, according to estimates. Each hour of continuous use for one whistle consumes about four tons of water and 1,200 pounds of coal. Sug gestions have been made that the whistle be moved ahead of the smokestack, so that its sound would be deflected much less, and.that it be constructed to give a high-pitched note which would longer range of audibility. have a FRONT AND REAR AUTO SIGNALS REDUCE ACCIDENTS Warning is given at the rear and at the front of the auto simultaneously for stops and turns by a set of signals oper ated from a switch at the steering post They are intended to dispense with the giving of arm signals and can be seen plainly at a distance of 200 feet. Stop and left signs show in red and right is given in green. Since the warning is Turning Signs in Front, Sides and Rear of This Car Are Intended to Prevent Accidents given before the turn is made, there is less danger of mishaps.

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POPULAR MECHANICS Shortly before the Launching, the Giant Hull of the Steamer “Vulcania,”” on the Ways at Monfalcone, Italy; Special Steel of High Elastic Properties Was Used in Constructing the Boat OCEAN LINER WITH NINE DECKS BUILT OF ELASTIC STEEL The upper parts of the liner “Vulcania,” recently launched at Monfalcone, Italy, are constructed of a special steel, which said to have high elastic qualities, pecially suited to ocean service. The hoat has a gross tonnage of 24,000 tons, 631 feet long, seventy-nine and one- half feet wide and has nine decks. RANGERS READ SNOW METERS THROUGH TELESCOPES Farmers and others interested in the water conditions for irrigating California lands, consider the depth of snow that falls in the Sierra mountains during the winter an important factor in their cal culations. Information concerning the now is furnished by forest rangers. At one station, a two-day ‘journey through drifts and difficult ground was necessary to cale a peak, make observations and re- turn. To eliminate these trips, a snow meter has been installed on the peak. It consists of a standard marked with cross From the ranger sta- away, the arms and notches. tion, eleven miles be plainly read gauge can vith the aid of a power- ful telescope. By counting the number of notches not covered by the snow, the observers can compute the depth of the snow without leaving their shelter. BARBECUE ROASTER FOR STORE FITS ON COUNTER Suitable for the drug store, restaurant or sandwich shop, a small barbecue roast- er occupies only thirty counter inches of space It is provided with pump which lifts the drippings from the meat to the top of a re- volving axle, around whichthe contents are placed, and dis- them Pork, beef, fish or fowls may be prepared in this outfit. charges over the meat.

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Rubber Mat beneath Flowerpot Pro- tects Varnished Surfaces; Ridges Permit Ventilation Affording Fresh Air with- out Opening the Windows a Ventilator Unit Is Easily Installed and Raised with a Chain; It Is Adaptable to Plain or Fancy Glass Both Sides of the Knife Are Sharpened at Once between Small Disks Rotated by Crank > Pan with Permanent Strainer Lid Has Han- dle That Keeps Cool Witha Vacuum Cup in the Base, This Flower Holder Sticks Firmly to the Bottom of the Dish Pits Pop Out of Dates Quickly and without Damaging the Fruit When This Instrument Is Used 638 Anyone wishing further information on devices described in the editorial pages can {

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For Holding Ties; Each Clip Has Room for Two Cutting Two Slices of Bread at Once; Adjustments Easily Made for Thick or Thin Pieces Portable Wardrobe Keeps Garments Free from Dust and Moths; Sides Lock by Pulling Small Tab; Holder [ Is Screwed to Wall -.= yx oa — Combination Water Heater Rubber Tip for Umbrella Prevents and Cooker Fits Oil, Gas or Slipping in Any Location; It Also Electric Stove Protects Eyes of Others = a ag 7 obtain it by addressing Bureau of Information, Popular Mechanix Chicag« (

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640 POPULAR MECHANICS MAKING HAY WHILE IT RAINS IS POSSIBLE NOW Dumping a Truck Load of Hay onto the Conveyor Which Carries It to a Cutter, and Then Delivers the Shredded Fragments to a Belt Moving through the Drying Tunnel, from Which It Emerges Cured The best-known farm saying—make hay while the sun is shining—may be ban- ished as a result of the developinent of successful apparatus to artificially cure green hay, even in a pouring rain. The hay curer makes it possible to save the crop in regions where excessive rainfall during the mowing season prevented cur- ing the grass, so that it was only useful in the meadow. The apparatus is not only a drier, but includes all the equip- ment, from a special mowing machine to the power grinder that reduces the cured grass to a coarse meal ready to be blown into the silo for storage. The gasoline- driven mower differs from the usual type in that it not only cuts the hay off near the ground, but also cuts it up in twelve- inch lengths, and delivers them into a motor truck driving alongside. From the truck the grass passes onto a conveyor, running through a low steel shed, 160 feet in length and twelve feet wide. Midway between the ends of the cur- ute, it takes the hay but little more than half an hour to pass through the shed, but only twenty minutes’ exposure to a temperature of 400 degrees is actuall needed to cure the greenest hay. Sixty tons of green hay can be cured in ten hours, producing twenty tons of dried product. The other forty tons represent the moisture that has been evaporated dur- ing the process. STREAMLINED RACING CAR HAS A NOVEL ENGINE Mounting a_ twelve-cylinder airplane engine, with the cylinders cast in blocks of four, necessitating special streamlined bulges on either side of the hood to cov- er them, a new racing car, built in Eng- land by Capt. Malcolm Campbell, em bodies a number of unusual features. Four of the engine cylinders stand ver- tically under the main hood, while the four on either side, projecting at ing shed is a fur- New Twelve-Cylinder Racing Car, Showing the Stream- an angle of sixty nace to generate the curing heat, while big electric fans cir- culate the warm air through the grass on the belt beow. Moving five feet a min- lined Side Bulges on the Hood degrees, fit into the side hoods, through which their short exhaust pipes project. The front axle of the car is more than eight inches long-

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POPULAR MECHANICS 641 han the rear one, the front wheels ng a track of about five and a half The body is so far underslung un- the rear axle, that rear tires two es larger than those in front are |. Developing slightly over 500 horse- er, the engine is extremely light for ize, weighing only 915 pounds. POWER FROM OCEAN WARMTH TO PRODUCE ELECTRICITY? wo French inventors are authors of an for utilizing the warmth of sur- e water on tropic seas and the cold- ;s of the deep waters below to furnish er. A for the idea is the fact t warm water can be made to boil by lucing the pressure on its surface. The entors propose to adapt this principle a gigantic ocean-power plant in some orable tropic locality. The warm sur- e water, which, in many such regions, vs at an average temperature of twen- six or thirty degrees Centigrade the r around, would be placed in a sort boiler, atmospheric pressure removed | the consequent basis steam utilized to rn a turbine before being condensed cold water from the depths. ng to reports, strate the Accord- a test outfit used to dem- idea, furnished enough ver to light three small electric lamps r eight or ten minutes. Critics declare, wever, that such a plant would have to be too large to be practical. Window Telescope in Use; Figures Seen Are Those of Three at Left of Glass TELESCOPE LENS ON WINDOW GIVES CLOSER VIEW Hung in the window, a lens serves as telescope, bringing distant objects within close range of vision. It is proving pop ular for country homes, and the support ing bracket obstructs the glass but little ABOVE-GROUND STORAGE BEST TO KEEP APPLES An above-ground cellar, with floor and walls of earth proved a better storage place for apples than either an underground cellar, floor and with similat walls, or a cork-lined storage cellar, according to ex periments made by Dr. L. M Marble, of the American Society of horticultural science. He found that the storeroom, same above-ground with its floor at the level as the surroundings earth, midity season, maintained a higher hu throughout the storage and therefore there less loss in weight of the stored fruit. higher the humidity was kept. the more moisture the fruit would al + sorb from the air The tests showed that the Hetbert Photo est Apparatus Which Produced Steam to Run Turbine and Light Small Electric Lamps for a Few Minutes , and the longet 1 it would remain in such conditiot as to be fit for sale.

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642 POPULAR MECHANICS GIANT FANS WHICH SAFEGUARD HEALTH AND LIFE ~\ Blower of a Giant Theater Fan, of Which Thousands Are Built to Protect the Health of Patrons in Crowd- ed Movie Houses Part of a Fan Capable of Pum; ing Twenty-Five Tons of Air Minute, Built for a South Afri can Coal Mine, Is Shown Above and Below Is Its Huge Rot Being Assembled Previous t Factory Test The Young Lady Stand- ing in a Fan on the Roof of a Theater Indicates the Size of the Ventilat ing Equipment Used to Protect Patrons’ Health and Circulate Cool Air in the Summer

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POPULAR MECHANICS HEAVEN PICTURED AS MAN’S IDEAL ENVIRONMENT (hat primitive man’s concept of heaven of a place of abode for the hereafter fers with every race and clime, but al- ivs represents the opposite of the ills holder faced on earth, was demonstrat- at the recent convention of the Ameri- n Association for the Advancement of ience by George T. Renner, Jr., of Columbia university. The tropical-for- t resident, he explained, pictured heav- as a remote village in a land of inac- vity, with no heat or mosquitoes, while e Eskimo placed heaven in the center f the warm earth and hell up in the cold ky. The Comanche Indian pictured heaven as a prairie full of buffalo, where he hunter never would want for meat, hile the more domesticated Todas im- gined it as a land of pastures and dairies. lleaven to the ancient Hebrew was a alled city on a hill, protected from the ravages of desert nomads, while the Mo- immedan pictures it as a delightful, well- itered oasis and imagines hell to be a corching place with hot desert winds. Invariably man created his picture of the hereafter by trying to minimize the evils nd emphasize the good on earth. DISK WEEDER FOR RAILROAD KEEPS BALLAST IN SHAPE To keep the railroad right of way free irom weeds between the ends of the ties ind the grass, a car has been adapted with con- siderable success. ire four ith a ich There sets of disks, man to operate and another man to run the car. The hafts can be set at va- rious angles and distances from the track, to reach eeds growing anywhere vithin the area covered on each side of the track. Besides cutting out the undesirable growth, the lisks prevent the ballast ‘rom being scattered and keep it shaped to the de- sired profile. Enjoying a Motion-Picture Show While Waiting for rain; the Cabinet and Screen FREE MOVIES IN RAIL STATION HELP PASS TIME waiting for trains at the Northwestern station in Chicago are en tertained by motion pictures displayed in an electrically operated cabinet. The film is projected upon a screen at the top of the box and is automatically adjusted for another showing when it has run through once. An attendant is not needed. The pictures are of instructive as well as amusing nature, enabling per- sons to improve their waiting time. Passengers been Disk Weeder and Ballast Shaper in Operation on Railroad; the Cutters Are Adjustable to Different Angles and Lengths

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or One Silkworm Cocoon and the Silk It Contained; Silk Gowns and the Transparent Fishing-Line Leaders Come from the Same Source, but Are Produced by a Different Process Robbing the Silkworm to Snare Fish How Busy Little Creatures Supply Human Needs from Dresses to Fine Trout Lines the silk- worm has no preference one way or the other. Left to itself, it will produce the material for the gown, but it also readily ‘supplies the strong line used by the fisherman in casting for trout. The silk gut of the fishing outfit is merely silk in its initial stage. When the worm approaches maturity, it de- velops two channels running along the sides of its body. In these ducts there is collected a sticky fluid which will harden into a solid mass if exposed to the air. This is the material which becomes silk gut when extracted before the worm be- gins to convert it into silk. The process of producing the line is simple, and consists in killing the worn: and soaking the body in strong acetic acid SILK dress or a fishing line -. until the gland walls can be removed. The fluid is then drawn out into the form of a fine line, which is stretched between two pins at the ends of a board and left 644 there to dry. The action of the sunlig! causes the material to harden into a se! blance of gut, producing a line of & treme strength, lightness and flexibilit An additional property is its almost co plete transparency in water, which giv it special value to the sportsman engag« in snaring the wary trout. Allowed to proceed without interruy tion, the worm converts the sticky conten of the two ducts into the’ silk fiber o general commerce. Normal developmer causes the silk glands to become so fille that their pressure makes it impossibl for the worm to eat, and starts it on restless ramble alonesthe branches of th mulberry tree which is its home. In thi journey the werm waves its sightless head in the air, seeking twigs to support the filaments about to be disgorged. The silk growers leave nothing to chance, and the twigs are ready and wait ing in a framework which constitutes a

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uw POPULAR MECHANICS 64 table factory for the production of the cious fiber. The process fascinates the cher. The silk issues from the two glands ough an opening in the under jaw, and kes its appearance as two sticky threads. \s they emerge, the threads unite into a sin- filament, cemented together by a viscous duid. Under exposure to the air this fluid

in hardens. \s wound into the cocoon by the spinner, . silk threads are so fine that 1,200 of them must be placed side by side to occupy the ice of a single inch. When the fibrous con- tent is taken out, the threads from < num- ber of cocoons are lrawn off together d united into a sin- e strand to give the necessary strength. he unreeling proc- ess is conducted by ind or by means of echanical reels. The mposite thread is twisted, the gummy ibstance boiled out, nd the mateiial is hen ready to be dyed nd woven. One co- oon will produce rom 800 to 1,200 irds of thread. The silkworm is a eature of long and honorable pedigree n_d a record of val-

Top to Bottom, the Chrysalis, with the Cast-Off Skin; the Moth Just after Leaving the Cocoon; the Spinning of the Cocoon, and the Moth after Finishing Its Life Work

uable service covering nearly 5,000 years. The useful career of this creature started more than 2,600 years before the dawn of the Christian era, through the activities of the Chinese Empress, Si ling, who made the first recorded study of the silkworm and of the handling and weaving of silks. Jeal ous of their secret, the Chinese rulers de- creed death to any person who should re- veal the mysterious origin of the fine silks they introduced into world commerce. The silkworm is in separable from the mulberry tree. Under a carefully wrought system of propagation and nurture the eggs of the worm are hatched by artificial heat at the season which brings the mulberry leaves into condition for feeding the new crop of silx producers. The eggs are so tiny as to be invisible to the naked eye, and so light that 45000 of them tip the scales at something like a single ounce. The hatching takes place on trays covered with perforated paper. An ounce of eggs may produce 30,000 silk-

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646 POPULAR MECHANICS of learning the secret production. His ent: prise was aided by t Persian monks who h spent many years China and had learn the whole art of the re ing of silkworms. Justinian induced monks to return to Ch and smuggle the ma rials needed for the c tivation of silk, whi they effected by conce ing a supply of eggs their hollowed stat This stock of silkwor supplied the wests world for more th twelve centuries FIVE ECLIPSES THIS YEAR Two eclipses of | moon and three of t sun, as well as the retu of several periodic c ets, are among the astt nomical events slated { 1927. Of the eclipse only one will attr much attention. It « curs on June 29 and vw be visible in Englar 1 Courtesy American Nature Association Silkworms at Work among Twigs of Mulberry Spinning Silk That Will Form the Cocoon from Which Silk Thread Is to Come worms will reach the stage of co During the thirty days of active feeding, the colony will dine to the extent of almost a ton and a quarter of ripe mulberry leaves. Later they will produce 130 pounds of cocoons, which coon production. yielding only a dozen pounds of silk. There is much romance in the story of the world’s attempts to penetrate the veil of mystery with which the Chinese cloaked the early centuries of silk production. Tra- dition sets forth that the eggs of the insect and the seed of the mulberry tree were in- troduced into India by a Chinese princess who smuggled the contraband in the lin- ing of her headdress. When silk fabrics had reached the Roman empire, the Em- peror Justinian resorted to various means early in the morning, t first eclipse seen there f centuries. June an eclipse of the moon will be witnesse throughout the United States at 3:13 a.1 eastern standard time; 1 wo the moon will completely hidden by the shadow of t earth. ‘he other eclipse of the mo: takes place in December but will not | visible in the United States. the visits of the comets, astronomers ca not be certain when they will Some time in June, the Pons-Winnec! comet, which returns to the neighborho« Concerni! of the earth every six years, is expecte to be much nearer than usual and visib without optical aid. has a period of Encke’s comet, whi three and one-quart years, will be visible through telescope there are, of cour chances that others may appear. it is believed, and happet t

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POPULAR MECHANICS 647 Samples of Unusual Designs in Venetian Glass; the Ma- terial Is So Expertly Made and Handled That It Can Be L Worked into Hundreds of | Artistic Shapes ca The Sphere MAGIC OF GLASS BLOWERS’ ART SHOWN IN VENETIAN PIECES Craftsmen in glass from Venice long e been noted for their skill in blow ng delicate and fantastic figures, and one the secrets of their art lies in the glass elf. It is iwn into light and can be rods These tubes are that the n work them into various shapes. extremely small canes or several undred feet in length. lored beforehand so blower BUS LINES SURPASS RAILROADS IN TOTAL MILEAGE Reports of the mmission interstate show that commerce there are more in 22,000 auto busses in operation in he United States, the mileage represented ~ | being nearly by the great routes majority of the lines are operated by motor transport companies LIGHT TELLS WHEN GAS IS LOW IN AUTO FUEL TANK Mounted on. the dashboat red ele tric lamp lig up hen the ply reache c_ is re { went of fuel e 1 tirel Only driver and pliet are needed to in stall it, and it forms an ornai li tion to the instrument board

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648 BULBS COOKED TO KILL PESTS BEFORE PLANTING Dipping a Box of Bulbs into the Cooker, to Kill Insect Pests before Planting To prevent the spread of the “eel-worm,” imported bulbs are immersed for two and one-half or three hours in hot water to kill the pests. A specially arranged cooker simplifies the process and insures an even temperature, a highly important factor to prevent damage to the bulbs and yet make sure that the worm will be killed. The outfit handles the bulbs in baskets, or their original shipping con- tainers, and the water is kept between 110 and 111% degrees Fahrenheit during the treatment. The can be op- erated by electricity, steam or gas. Small growers in some sections of the north- west have a community cooker that serves a large number of farms. cooker MEN ARE SEEN THROUGH WALL WITH TELEVISION’S AID “Looking in’ will be as common as listening in to radio programs, according to the prediction of research workers who have been spending much time of late in experimenting and developing this recent marvel. At a demonstration in London, J. L. Baird, a Scottish inventor who in- POPULAR MECHANICS troduced television in England more than a year ago, showed what progress h been made when he permitted persons in a darkened room to see others in an u: lighted room through walls. At this te use was made of the infra-red rays whic! are invisible to the human eye. In t! earlier experiments with television, the subject had to sit under powerful light which proved harmful. SMOKESTACK USED FOR MOVIES ON OCEAN LINER A motion-picture outfit and its operat: are to be snugly quartered in one of tl smokestacks on the steamer “Malolo the movies being projected upon a scre mounted at the bottom of the after mas! The funnel is a dummy, as is the case wit the second stack on a number of mode: vessels. The steel cylinder will affo: ample fire protection and shield the i: strument from the weather. HOUSE MAIL BOX HAS BELL AND SWINGING DOOR For the greater convenience of the ca: rier as well as the owner, a combinatio: mail box and bell for house use has bee introduced. The bell button is just b: low the door so that the carrier can easi signal his arrival and the door is of th swinging type. It opens one way f mail delivery and the other for mail that is to be removed from the box. Mail Box with Swinging Door Opened and Closed; Ease of Extraction Is Apparent

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Se utdoor & sy ee st rally 83: a” rt = en ‘ I tad _ ghr3 das ee ct) S goat te GOR CY rn = Fen a ; . saat oY la We a -~*% flay _ = Fig. 1. CO™= of the most important parts of every receiving set is the aerial, or ntenna, which picks up, or absorbs, the energy sent out by the broadcasting sta- tion. It usually consists of one or more re copper wires, stretched between in- ilators, and elevated as high as possible o that it will not come in contact with trees or other obstructions. With warm- weather coming on, outdoor-aerial mstruction becomes a pleasure, rather han a hardship, and a few hours’ work now will earn a reward of long-distance eception during the winter. While the past years have seen many tvles of antennas grow in favor, the out- loor aerial still holds its own. The in- verted “L,” the “T” and the single-wire traight aerials are- the commonest types of outdoor aerials. The inverted “L” ierial gets its name from its shape, shown in Fig. 1. It is widely used and with good results, though it has one defect—its di- rectional property. This, however, is sometimes turned to advantage; it re- ceives the loudest signals when the end to which the lead-in is connected is point- ing toward the transmitting station. For example, if you are located at a point on the middle Atlantic seaboard, most of the distant stations would be located west, and it would be advantageous to run the aerial east and west, taking the lead-in from the west end. Most satisfactory aerials of the invert- ed-L type employ two wires when the space between the insulators does not al- low a single wire of 50 ft. or more. When it is made with these should be spaced 3 ft. apart, a light piece of wood being used for a spacer. Such an aerial should be at least 35 ft. above the ground and it is better if it is 50 or 60 ft. high. The lead-in should, of course, be taken from the end nearest the receiving set, and, in all cases, the connections should be care- fully soldered. If space is available for a one-wire type, it is a good idea to make the horizontal part and the lead-in continuous wire. A turn or two around the near insulator will anchor the wire, and no soldered joint is necessary. The T-aerial, as the name implies, is T- shaped, as shown in Fig. 2. It is free from the directional properties of the L-type, and receives from any direction equally well. A single-wire T-type aerial should be at least 100 ft. long, but if con- ditions prevent putting up this type, a multi-wire construction must be used. two wires, one 649

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650 POPULAR MECHANICS Four or more wires should be placed at least 2 ft. apart, and the lead-in taken from the middle of each wire. These lead wires should then be bunched and soldered to a single lead-in, or may be taken down fanwise if practical. The lead-in wire to which the bunched leads are soldered should always have the same area, or cross section, of wire as the an- tenna, to avoid cutting down the capacity of the aerial. This also holds true for the one-wire type, where a separate lead- in wire is soldered to the horizontal sec- tion. Generally the multi-wire type is used on apartment houses or other build- ings, and in such cases it is best to place it above any other aerial that may be on the same roof. The straight-line aerial, shown in Fig. 3, has a very short lead-in, coming almost direct to the set. Generally, one end, eee preferably the set end, is lowest, the far end being elevated above roof and tree-top interference. This arrangement is fav- ored by many because of its simplicity and _ eff- ciency. As in any an- tenna of the one-wire type, the aerial and lead- in should be in one piece, if possible, in order to cut down any resistance that a poorly soldered joint might cause. It will be noted that but one mast is required with an aerial of this tvpe; the total length of wire, including the lead-in, should be 100 feet. When constructing an outdoor aerial of any type, it is necessary to use some form of approved lightning arrester; this device is screwed to the building at a point convenient to the inlet to the set, and is shown in the inset illustration on page 651. It will be noted that the lead in is taken directly to the set, an extra wire being soldered to the lead-in and taken to the terminal marked aerial on the arrester. The other terminal of the arrester is grounded outside the building. In the same illustration the lead-in is shown coming down over the edge of the roof, and is carried out over an insulator; this should be done in all cases where the lead-in is likely to come in contact with the building. Heavy sleet or high winds will often bring the lead-in in such contact, and the set own- er will wonder why the signals come and go, or go altogether. This is easily prevented by care- ful insulating, and the installation will last al- most indefinitely. When we realize the minute strength of the signals as picked up by the aerial, the impor tance of good insulation becomes apparent. A YO

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POPULAR MECHANICS od aerial installation is just as ential as a good set, and be- re beginning its construction e following details should be pt in mind: Over-all length over 125 ft.; no close ap- oach to trees or buildings, and e horizontal part as high as issible; furthermore keep the id-in away from building; make ) joints if they can be avoided; e as few insulators as possible; re should be No. 14 and kept taut as possible, and clean nnections throughout. Height of course, also an important ctor. There are a number of <cellent steel masts now on the irket, in both the earth and of types, which are available lengths of 20, 40 and 60 ft. he roof type is furnished with an lapter so that it may be mounted n either a flat or a peak roof. The erection of the mast should re- eive careful attention. The steel. masts eferred to are light, strong and easily et up. All guy wires should be galva- zed and securely fastened to insure roper wind resistance. It is advisable » use a masthead pulley so that the aerial in be raised or lowered at will with the east possible effort. The set ground is also a part of your erial system and should be given care- ul consideration. The ground lead should re as short as possible, and connected to Adjustable Crystal Mounted on Panel \n adjustable crystal of the multi-point type, designed for panel mounting, is hown in the illustration. It is fastened through a sin- gle hole in the same manner as a condenser or rheostat, and the %-in. shaft is provided with a knob at the outer end. This rotates the crystal cup by means of a worm gear and the contact point of the cat whisker is raised and low- ‘red automatically for each new position 651 Above, Steel Aerial Mast of the Roof Type; Insert, Method o Mounting Lightning Arrester on Outside of Building

a.water pipe with a good stout ground clamp. The point of contact should be filed bright, as a poor ground connection renders the entire system inefficient. A good aerial is well worth the trouble it takes to make, for where the average set brings in distant stations occasionally, the man with a first-class aerial will get them consistently, and high-priced radio sets often may prove disappointing or even a total loss, as far as distance recep- tion is concerned, if the aerial is not erected in the proper manner. by means of a small cam. About 250 sen- sitive spots on the crystal can be reached before readjusting is necessary. Setting Rheostats with Milliammeter If a milliammeter is used in the set, the exact amount of B-battery or plate current consumed is visually checked at all times. When the rheostats are turned too high, an excessive plate current is used while there is little or no increase in volume. The rheostats can be regulated so as to use the minimum amount of B-battery current consistent with volume. Without a milliammeter there is no way of determining this consumption. good

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POPULAR MECHANICS All-Metal Receiver Is New Departure A.receiver of practically all-metal con- struction and with one-dial control, is now attracting attention. The only parts that are not of metal are the tube sockets, which must be mounted on insulation, and the coils, which are wound on bake- — head is need not interest us greatly, but the breakdown stopped the ship. With in ten hours temporary repairs had bee: made, and the ship was under way again The chief engineer, one Mr. A. U. Cross while satisfied that the repair would hold up, naturally desired a more substantia job than could be done with his limited lite tubing. The all-metal chassis supports the va- riable condensers which are made up of one-piece die-cast metal, and are balanced and matched to make one-dial control practical. Accuracy of tuning is achieved by an ingenious float- ing drive, in which wear is automatically taken up by spring tension. worm-gear The coils are mounted in a copper shield, thus eliminating pick-up from strong lo- cal stations and making selective tuning possible. The cushioned sockets, and formers, mounted on the audio trans- assembled with the sockets ona tubes are metal base screwed to the chassis, com- plete the set. The glass front panel shown is used only for display purposes. A Picture by Radio An Australian ship was proceeding down the Gulf of Aden, a place where the tem- perature in the engine room reaches 154’, when the air-pump off its crosshead stripped rods. What an air-pump cross- ry equipment aboard, yet he did “| not want to tie up the ship fo: any longer timethan necessat at the nearest repair shop With the resourcefulness of thi marine engineer, he de cided to try his hand sending a “picture” of the radio to the repair shop. Here is a part of the message Colombo, Cey lon. usual crosshead by *, oof (a8 Above, Set as It Appears in the Display Cabinet with Glass Front Panel; Below, Complete Unit Assembly Removed from the Cabinet he sent: “Due noon Monday; require steel crosshead for air pump, forged solid, con sisting of center rectangular block having on each side tapered piece terminating in journal pin for link brasses, end of pin having Front over-al! length sixteen one-eighth, rectangular cen collar. elevation ter three seven-eighths long, seven deep.” There was more of it, but this is enough On the ship’s arrival the job was done. Radio Soldering Hints A small electric or plain-heat iron, some wire solder, and a smali tin of soldering paste, make up the simple equip ment required to do a Have the iron hot enough to flow the solder o1 the joint; never brush it on. bit of flux paste on the end of a toothpick, common good 10b. Use a smal

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POPULAR MECHANICS ly it to the joint to be soldered, and then e it off, the idea being to leave only a ht film of flux on the joint. The iron t be clean; a dirty iron, or one not hot ugh, will not make a good joint, as the cannot reach the joint if the end of iron is corroded File the soldering per clean, and tin it well so the solder stick. Never apply the hot iron to d condensers, and use soldering lugs all instruments likely to be injured heat. When building a radio set ploving exposed coil windings, do not unt these coils on the subpanel until the soldered joints possible have been pleted, as one will often accidentally ch the coils with the iron or drop solder the windings, causing short circuits. hen the coils are mounted and soldering to be done around them, protect the ndings from the iron with a metal shield, | cover the coil with a small cloth to event solder from dropping between the irns and damaging the insulation. These recautions refer to all sets, but particu- ly those employing unprotected. sole- id windings, and coils of the toroid or ughnut type. New Insulating Material Easy to Work \ new insulating material that is easy work and is claimed to have exception- insulating properties is now available. This is said to com- ; product oe bine the strength of steel with the high insulat- ing qualities of rubber and porcelain and the adapta- bility of wood, and can be sawed, drilled, tapped and punched with ease, clean holes being drilled with hand drill, as shown in the illustration. t is suitable for panels, jack spacers, transformers and general insulating, and Onsists of laminated bakelite, made by irefully impregnating fibrous materials. Preventing Tube Vibration When great volume is developed in the loud speaker, and the latter is on or near the set, a heavy vibration will sometimes be set up in the tubes. The result is a Placed over the Tubes in the Set, the Rubber Fingers Grip the Tube, Preventing Vibration loud hum from the speaker, which often rapidly increases until it becomes a roar, drowning out the program. ‘The detector tube is the most frequent offender, al though any tube in the set may develop the trouble. When the vibrating tube is held by the fingers, the noise will stop. The spring-clip device shown in the pho- tos has been developed to cure this trou- ble, and usually proves effective. Doping Coils Increases Resistance Coils, doped or bound with any of the various preparations used for the purpose of mechanically strengthening them have a higher resistance. This causes a loss of efficiency, and tends to lessen selectivity ; if a binder must be used, eollodion is best. Coils of the solenoid type are considered to have the highest efficiency. These single-layer coils do not require a binder. A skeleton form can be used with good results: a form of this kind can be made out of bakelite tubing by cutting it away as much as possible without weakening it so it cannot support the winding. @ Leads hanging over A-battery vents are soon destroyed by fumes when battery is being charged.

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POPULAR MECHANICS Right, Under-Sub- panel View of Com- leted Set; Below, ee Down on the Subpanel Five-Tube Receiver in Kit Form A five-tube receiver in kit form, ready to assemble and wire, has lately made its appearance on the market. The circuit, although not radically new, embodies some interesting ideas. The outfit sists of two stages of r. f. amplification, a detector and two stages of audio fre- quency. Only two tuned circuits are used, the first being the input to the first r. f. tube. and second tubes is through a fixed r. f. especially designed for the set. The neu- tralizing or balanc- ing condenser is mounted on the front panel. This permits a slight va- riation from the neu- tralizing point and introduces regenera- tion in the first tube. The signal is built up to a large degree and transferred to con- obtained transformer A Power Device, The coupling between the first Showing Lid Removed from Metal Container transformer. The audi end consists of two steps of transforme: coupled amplification, employing a powe: tube in the last stage. the fixed r. f. Conduit Makes Good Aerial In apartment rules against bringing the ra dio lead-in through a front window make it impossible to erect an houses where aerial and keep the lead wire within reasonable length, the metal conduit system will be found to offer a good substitute Place the radio set nea: one of the base outlets which furnishes a hand place for plugging in the battery charger. outside Looset one of the screws whic! hold the brass plate o the outlet and twist th: end of the aerial lea around it, then tighter the screw. The entir: metal-conduit system ot the building then becomes the Tried out against the usual inside aerial! placed around the picture molding, th electric conduit proved superior, gettin; greater distance and better volume. aerial New Unit Replaces Storage A-Battery Replacing the A-battery with a con pact unit connected with the house-light ing circuit, the device shown in the illus tration is a welcome addition to moder: radio equipment. A steady, un failing A-current of 6 volts, re gardless of how long or ho often the set is used, is claimed for this new device. It is state that there is no hum or distor tion, and the instru ment operates onl while the set use. It for receivers em is 11 is designed ploying from fou to eight tubes of the stand ard ™%4-amp. type nals marked A-negative an A-positive are provided

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An Unusual Homemade Radio Cabinet By EDWIN M. LOVE rt’OO often the amateur radio-cabinet maker confines his work to plain, box- ke pieces with square posts for legs. he introduction of curves into a design enerally much improves the appearance f the article, and need not materially nerease the difficulty of construction. the design presented here, console nes are followed, but several unusual eatures are added. Space for a cone-type ud speaker is provided underneath, the liaphragm lying flat, so that only a narrow rill betrays its presence. The case it- elf is readily detachable from the stand, the removal of six screws, and a book trough takes the place of the more com- mon stretcher. The cut on this page shows the front dowel 2 in. from the upper end, and one 5 in. from the lower end. Let the glue harden while other parts are made. General construction details of the case are shown on page 656. Glue, edge to edge, two pieces of 1 by 8 by 20-in. mate- rial for the partitions, and, for the bot- tom, two pieces, 2 ft. 9 in. long. The molded lower or long rail is of 1% by 2-in. stock, sized to 1 by 1%-in. Square up two pieces, long enough to make all molded rails, and % in. from each edge, on the face sides, plow %-in. grooves, %e in. deep. Then, with plane and chisel, round off the center part to the profile shown in the cross section. Make a rub- bing block, 1 in. thick, with an are of ™%e- in. radius worked in the edge, and use it /~ GUT PANEL S§X75" ! ” ——— 153 ———+ i + 145 saline OR a | in sanding the mold- ing smooth. This is really avery easily cut pro- — CUT PANEL — -| 124-% 7% be -——— i2—== ———»4 I" SQUARES elevations of the dimensioned for a 7 by 18-in. panel, although a longer panel can be used simply by lengthening the middle section of the case. The outlines for the legs and and end cabinet, brackets are easily copied by laying out a piece of paper in l-in, squares, and locat- ing the intersections of the curves with the squared lines, as they appear on the design. If 14-in. stock for the legs is obtainable, use it; but as such wide material is often difficult to get, it probably will be necessary to glue up for each leg two lengths of 1 by 8-in. stock, 18 in. long, using a %4-in. hardwood

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POPULAR MECHANICS FRONT UPPER RAIL N PANEL STOP ——. 7 - UPPER RAIL ; PARTITION } UPPER END RAIL | The four corner stiles are finished 1 b 1 in., 10% in. long. Gauge lines % in from each face side, and rip out the back corner strips, % by “% in., as indicated Smooth the strips with a rabbet plane, and notch the inner faces, 4% in. deep, so that they will fit over the tenons of the upper and lower rails. The long upper rails are sized exact), to 1 by 1% ir BOTTOM 7 VENEER PANEL — By by 2 ft. 7 in., and the ends notched full width in. deep an | js" u wee 4 STILE, 4 REQUIRED Mi 3... K— 13. # cal I file, and will be found sur- prisingly rich in appearance. For the end rails, cut a 13'-in. length, from each. by “4-in. groove *s in. Plow a 36 from the front, on the upper edge of each, and rabbet the back the lower in., as shown, to receive the bottom. Lay off the ends for the mitered tenons, giv- ing the molding a length of 12 in. and the tenons % in. These are notched in from the molded faces “4 in. Rip the tenons to thickness before sawing the shoulders. Miter the ends last. The long rails are somewhat more com- plicated. Make tenons on each, as for the short rails, giving a length of 2 ft. 5 in. from shoulder to shoulder. For a distance of 5 in. from each shoulder groove the upper edges as in the short rails, to receive the front panels of the battery boxes. Likewise rabbet the backs on the lower edges. This can be done quite’ easily by accurate gauging, and cutting cross chips with chisel and mal- let. Finish the blind ends square, for such bracing effect as they can offer. 27 lace on edge, 34 by MY 1 in. long. These fit over the stiles and the short-rail tenons. Groove the lowe1 sides 3g by % in., 34 in. from the faces, and notch the upper edges of the short rails at the ends, 4 in. deep and 1% in. long, to take the tenons of the long rails. Also notch the , by 34 in. Cut away the inner sides of the grooves ‘2 in to fit over the front sides. ! face back from the ends, panels. Square the partitions as shown, mak ing them 1 ft. 2 in. wide and 9% in. long. with the upper corners notched 1 by 1’: in. to fit around the upper rails, and the lower ends notched ' 2% in. Dado one side of each, 344 by % in., 1 in. fror the lower end, and rabbet the lower end = by

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POPULAR MECHANICS he opposite side, 4 by 4% in. Notch ados, % in. below the long notches own, and groove the rabbet faces, in., °S in. from the edges. ke two front and two back panels .-in. three-ply panel veneer, 5° - two end panels, 12% by 7% in., and k panel, 7 by 18 in. Make two short ms, %& by 12% by 5% in.; 8 by size the giving them one coat of elue. Make the long center bot- 1 ft. 6% in. long and 12 in. wide. both ends. Size the end grain of dados and rabbets in the partitions, notches, shoulders, and tenons ends by 1 +1 e the rails. assemble the case, proceed as fol- Glue the long bottom into the par- n, securing it by ng nails through partitions, leav- the heads pro- ting so that they Glue LONG RAIL la be drawn. e long rails to the and the ng bottom, nailing rtitions ,--- ENDS HOUSED j INTO LEGS 657 the bottom, and mark the positions of the lid corners. Miter the ends through these points, and r-splace. Wedge tightly enough to prevent its shifting, and fit the endpieces. With one in place, fit the other edge strip, and then test all in When good joints have been obtained, glue the strips in, and round off the edges. it touches place. Two or three methods are available in shaping the legs. Trace the pattern on the prepared stock, and saw to the out- line with a turning saw, or cut roughly to shape with the handsaw, chisel nearly to the line, and finish with the spokeshave and Any planing mill will band- saw them and shape the edge for a small price. If it is cut by hand, smooth the concave curves by filing in diagonal strokes, twisting dur ing the strokes, and lifting on the back movement. Finish with sandpaper. On the lower end, cut a tenon 214 in. wide, 34 rasp. hrough the top rail in. thick, centering into the partition, from the rabbet nto it, but leaving e heads out so they can be pulled. \pply glue to the rail grooves and RAIL ' SECTIONAL VIEW ‘THROUGH CABINET the thickness of the stock, and 2 in. long. Rip the cheeks and the edges before cutting the shoulders. on the panel edges, and force the front inels into place, immediately wip- off all surplus glue.. This is feasible only if veneer is used, since will not shrink or swell. Glue and nail he end panels between the front ones, iin with the nail heads projecting. Glue he upper end rail in place, and then the wer. See that all joints are snug, and it the whole assembly is square, and set ide to dry. should be five-ply The lid preferably veneer, 34 in. thick, but solid stock can be used, if stout cleats are screwed to the underside, where they will enter the in- trument section, out of the way of the itteries. The finished size is 34 in. by 1 t.3 in. by 2 ft. 8 in. Plow a %6 by %-in. croove all around the edge, % in. from the top face, and glue into it a n. strip. Make this just thin enough to lide in and out without the need of prying. ‘lip a piece in a long edge, being sure that “46 by “6- Locate the mortises for the trough sides. as shown, remember- ing that they make with each other, and 45 with the center line. If there is any varia- tion, the two legs will be held in a twist. The mortises are 4 in. long. Since the ends are semicircular, a 34-in. bit can be used for cutting them, but take care that the point does not prick through. Chisel out roughly, and trim to the line, bringing an accurate depth of % in. I4-in. grooves, 34 in. from the edges at the upper ends, to receive the ends of the speaker grills. Mortise %4 in. deep by 3% by 1% in. for the ends of the erill rails. Make brackets of 1 by 4-in. stock, allowing 14 in. on the ends to house into the legs. The two trough boards are 34 by 4 in. by 1 ft. 6% in., edges rounded. Size the ends. Make two grill rails of the same length, an angle of 90 Plow 3% by lower two with

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658 POPULAR MECHANICS 4% in, thick by 1! ¥g by 4 in., 344 in. from the outer edges. Notch the ends % by &% in., to fit the leg mortises, and size the ends. Make two upper rails 6 in. wide, plowed Clean up the cabinet thoroughly hinge the lid to the back with 2 by brass butts, mortised in. Glue striy by 1% in., around the radio-panel o; ing, *% in. plus the panel tl from the front, to act stops for the panel, which is | drawer-style, to pull out the front. Similar stops are in the back, % in. from the for the gluing in of the ve: panel. Finally, glue %4-in. cl to the: lower rails the bottom. Secure the speaker to the derside, and hold the position by means of two ser f ness undern: Cast 2 UPPER SHORT RAIL, 2 REQUIRED like the lower, but 1 ft. 6 in. long, and without the notches, as they go between the lower ends of the case partitions. Make two grills of panel veneer, 2% in. wide and 1 ft. 6% in. long. Gauge lines, full length, 1% in. from the edges. Divide for the lengths of the openings as follows: ¥% in. from each end; 2 in. farther; 1% in.; 3% in.; 4 in. Bore ™%-in. holes in each space and cut out with a fine keyhole ora bracket saw. Trim the ends smooth, with corners rounded to a radius of % in., and sandpaper them. Assemble the with the trough boards and the lower grill rails, and glue in the grills. Screw cleats inside the grill ends, and also inside the upper ends, giv- ing them 3%4-in. projection above. Make two feet to the design shown, of 1% by 5-in. stock. Cut the mortise before shaping the curves. Then glue in the leg tenons. Now draw out all nails from the case, and glue the corner stiles in place. Glue in the end bottoms, and miter around the top rail a %4-in. quarter-round, secured with brads which are drawn when the glue is dry. Bore %-in. holes through each long upper rail into the partitions, for the gluing in of dowel pins. legs through each leg cleat into partition ends, and one throu the tip of each bracket. Ser and sand out every scratch all visible glue before finishi: The original speaker used y this cabinet fitted into a 4 by by 12-in. space. Since there no bottom to the speaker c: partment, any size of speaker can be commodated here and any projection low the grill would usually be unnoti able. Of course, the width of the ¢: could be altered to suit a large speake: unusual “thickness.” Salvaging Old B-Battery TIO ADIT a / Many B-Batteries, when discarded cause of a great drop in voltage, still } a few good cells left. These cannot liver their power because of the high sistance in the dead cells, but they shou not be sacrificed. If the batteries have cardboard container, tap around the PARAFFIN CONNECTING POSITIVE WIRES LEAD . edge wit] hammer, ca: fully chippi: away thre se ing compou: from the ce and taki care not break the c: bon elemet in the cel! Remove t! connecting wires and binding posts wit! soldering iron. Now test each cell with \ B- BATTERY CELLS CARDBOARD BOX

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VIO A IV a / pper POPULAR MECHANICS flashlamp; cells that produce only clow in the lamp, going out in a few tes, cannot be reclaimed. Cells that up the lamp brilliantly may be used king up a new unit. For this, a con- such as a candy box will do nicely. the cells in the box in the manner 1 in the illustration, connecting them 1eS The ca rbon or top terminal is sitive, and the zine shell the nega- Solder small flexible leads to these The box should be about % in. - than the cells are high; space the ihout 4%. in. apart, and pour in melted ffin very slowly. It is best to pour in half an inch at a time, permitting laver to cool before adding more. binding posts are tapped off to leads enough to permit mounting them on ide of the container. A Good Ground Connection importance of a good ground con- ion fe sed too much. yr «othe radio set cannot be It is well known that ordinary cold-water pipe offers a good — \ ! | ————— ee ——=__ — ae —————_ a ————— tration to secure a good contact. mm GROUND WATER PIPE shows und the pipe wn in the sketch. ground, and it is generally availa- ble. To solder a wire to the pipe difficult, and while there are a number of good ground clamps on the market, usu- ally, when needed most, they are not at hand. The il- simple and effective The pipe is a first scraped or filed around the portion m which the lead is to be taken; heavy pper wire of about No. 12 size is wound and a metal plate, as Drill a hole in the te near the end, and insert a common ve bolt on which are screwed two nuts, ne on either side of the plate. By screw- ‘ down the bolt, the plate acts as a lever, | the wires are drawn tight on the pipe. ne end of the wire is fastened by the nut; the other is wound under the t turns, and the No. 12 wire is con- nued to the ground post of the set.— irold Zahl, Naperville, Ill. 659 Added Pin Improves Tube Contact encountered the tube This may be traced to the often between socket springs. fact that there is only one pin on one side of the tube which engages with the socket shell. The tube is held down well on the pin side, but the con- tacts on the opposite side not proper con- nection. This condition is remedied by drilling a hole in the bakelite tube base, tapping it with a 4-32 tap, then driving in a brass machine screw of this size and chipping it off so that about “6 in. projects. In the socket, at the point where the new pin should connect, a slot is made exactly like that on the opposite side. This makes a double- bayonet base, which is sure to pull both Trouble is contact by prongs poor and base, do make sides of the tube down evenly.—Harold P. Strand, Malden, Mass Detector Crystal Has Vernier Adjustment A cry stal, fitted for either panel or subpanel mounting, is now vernier detector available. The special features are pointed out in the illustration; the automatic spot finder is for the coarse adjustment, and the vernier knob at the front provides a fine contact regulator for obtaining maximum re- sults. The crystal r AUTOMATIC SPOT FINDER ---~. CRYSTAL RENEWAL CUP VERNIER CONTACT . REGULATOR, ‘CUP BINDING POST e- cup at the rear is de- tachable. The neat design and simple method of mount- ing make this unit a desirable addition to any crystal radio receiver. PANEL OR BASE MOUNTING - CONNECTOR ---~ BENDING MARK ‘ FOR BASE MOUNT- newal

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660) POPULAR Light-Plant Interference Eliminator A device for eliminating interference from light plants, and motors of all types, is now available. In plants of the farm- Interference Eliminator Ready for Installation and Various Electrical Trouble Makers lighting type, the instrument is of special value as interference from this source is very common. Interference from various household electrical apparatus is of frequent occurrence in cities. This de- vice can be: used on all such appliances without disturbing the efficiency of the apparatus. It furnishes an easy path for the escape of the interfering vibra- tions to the ground and builds up a bar- rier that prevents them from going to the electrical wiring and causing disturb- ing reradiation, not only in the house but in the whole neighborhood. Why a Power Tube Is Used There is, perhaps, no more misleading name among radio terms than “power” tube. The mere addition of a tube of this type to a receiving set will not in- crease the volume tremendously, as is usually expected, for it is not a source of power. It can, however, handle far gfeat- er power than the usual tube, and in this lies its advantage for quality rendition of.radio programs. The standard A-type tubes have limited capacity. They can handle the minute currents found in r. f., detector and first audio-stage operations, but for the last amplifying stage they MECHANICS cannot pass the full power of a m tube set without distortion. There the loud speaker is not operated at where near its full capacity. As adds the final touch of realism, an bass notes require far more power the higher notes, a tube capable of dling this increase without overloa: choking and blurring reception is esse1 vol Simple Test for Open Secondary A simple test for an open second where the terminals can be reached the fingers, often locates the trouble qu ly. Wet two fingers slightly and p them across the secondary of the transformer while the set is in operati: if the volume immediately increases there is less distortion, the secondar open at some point. The best reme of course, is a new transformer. The ey planation of this simpie test lies in grid return provided by the fingers; tube choked up because there no grid return, due to the open windi: and the fingers allowed the charge leak off, thus increasing the volume. was Decorating the Cone Speaker The cone speaker is an excellent strument, but there is something blan! about its appearance that makes it sightly. It may be greatly improved fact, it can be made very decorative ornamenti! it with so design su shown illustr tion. This simply ma by cutti out a part from cre} as the paper mounting on the fro: of the spea er by mea of glue « shellac. large number of suitable designs may a found on the modern crepe papers us« for decorative purposes.

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Radio Happenings Far and Near Above, Carl Menzer’_Broad- casting Grid Game between Universities of Iowa and Min- nesota from In- closure above Grandstand Upper Left, Dr. Austin of Bu- reau of Standards Making Ob- servations with Giant Double- Axis Loop; Right, Huge A. F. Transformers Used in Test by English Manufacturer to Prove Need for Large Iron Cores; Be- low, Apparatus Used by WGY to Create the Sounds of a Train

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662 POPULAR MECHANICS Suspended Loop Saves Space Even a comparatively small loop aerial occupies more table space than the radio OAT | JOIST---s | = A BRASS ~ | "(BALL ? wy '. yy SLOT, ITN HOLE PY ig BRASS STRIP - 3 — —S— NET Sh WANNA a — = Loop Suspended from Ceiling, and Details Showing Bearing and Mounting Strip fan is prepared to allow it. A 4-ft. loop for long-distance work is too large for the average living room, if used on the table. One practical solution of the difficulty is to suspend the loop by means of a universal bearing from the ceiling. The bearing showr’ in the drawing is simple, and permits easy insertion and removal of the loop. When not in use, the loop may be lifted off the ceiling bearing and hung flat against the wall where it will take up very little room. The bearing consists of a 1l-in. brass ball screwed to the end of the loop shaft, -no further alterations in the loop itself being necessary. A slotted brass strip, fixed to a .ceiling joist, supports the ball, the slotted end being just wide enough to admit the screw shank. The ball rests in a “-in. hole at the end of the slot. This ball bearing will cause the loop to hang vertically, and allow it to be turned readily in any direction—C. A. Oldroyd, 3arrow-in-Furness, England. Placing Coils in the Set Interaction between coils in a receiver can be minimized or eliminated if some attention is given to the locating of the coils in assembling the set. Coils of the _single-layer or solenoid type are the w: offenders, but if placed in the set . rectly in relation to the other coils, t! will give very little trouble in this respect Energy will not be transferred by ind tion into another coil, if the plane of th wires constituting the winding is at ri angles to the wires of the other coil. Simple Tube Tester Employs Lamp A simple and efficient tube tester, « ploying a small glow lamp, has recent! made its appearance on the market. T! radio owner without technical knowled of tube characteristics can use this vice to determine the efficiency of various tubes inthe set. The tester sh: instantly whether a tube is in conditi for satisfactory use and in what capacit the several tubes of a set will oper most efficiently. It does not measure t various elements of the tube separate but their effective combination unde! working conditions. To use the instru ment, the plug is inserted in the socket of the set and the tube is placed in t! tester socket. The rheostat, controlli: the filament current to the socket which the plug is placed, is then turn up till the small lamp in the tester glow If the lam does not gl when the rhe stat is turn: onto fulle pacity, th tube is n¢ good. Shou the lamp glo before the rhe ostat is turn: on fully, the quality of the tube may measured by the amount necessary turn on the rheostat before the glow b« comes visible.

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S SSS SS Twenty-Three Miles an Hour from Your Outboard Motor ’ the annual regatta of the Missis- 4 sippi Valley power-boat association, at Louisville, Ky., July 4-6, 1926, hiz,” a 14-ft. step plane, established speed record for Over a outboard-motor straightaway es, covered six times, the average 23.383 miles per hour. This speed, for an outboard motor, due not only mil ad Was rtling to the engine used but to the design of the hydroplane, and course of we take pleasure in presenting complete specifications and drawings for the build- ing of a plane to the same design. There is only one thing on the draw- ings that may puzzle the amateur builder, although it is a common practice, and that is the method of indicating angles and bevels. It is very simple, It will be noticed that, is indicated on the cross section of a rib or other part, there is a little triangle how ever. wherever a bevel Johnson Motor Company Sheer Plan of the 14-Ft. Step Hydroplane in Which the Speed of 23.383 Miles an Hour Was Reached with an Outboard Motor

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Constructional Details of the Hull of the Hydroplane; Any Boatbuilder Can Assemble a Speed Boat from These Plans, and Even the Amateur Will Not Find It a Difficult Task 664

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POPULAR MECHANICS close to it, with the fig- 1 to 12 in., or sim- ilar figures. This sim- ply means that if a right- FY angled triangle is drawn, the sides adjacent to the right angle being, re- pectively, 1 and 12 in. long, the side opposite the right angle is at the exact angle of the de- sired bevel. The method is similar to that used to indicate the steepness of a hill, when we say it ures m=? ‘ \Yyroe” pets? r y ry Ler - ty 1" ~--g *\g BOLT _- PLANK IS NOT NOTCHED CHINE DOES NOT EXTEND THROUGH STERN BOARD rE SIOVE ; LY T mJ “_ ge STOVE BOLT \ fo 72° has a grade of 1 in 100. The ribs are of spruce, % in. thick, with the ex- ception of the bottom member of rib 3, which % in. thick; all are to sawed to. shape, notched, beveled and as- sembled according to the drawings. Side and bottom members are joined by cop- per rivets, and fastened at the proper stations to the keel by two 1%-in. No. 6 screws through each. The keel is of spruce, % by 1% in., and is in two lengths, one running from the stern to the step, or station 3, and the other from step to bowpiece. The joint at the bowpiece is fastened with two % by 1%-in. bolts, spaced on 3%-in. centers. The bowpiece is of rock elm, 2 in. wide, 1*s in, thick at joint, tapering to 1 in. thick at sheer line. It is in one piece, properly beveled and steam-bent. The stern is of cedar, * in. thick, sawed to shape and nail-fastened (clinched) to the stern frame, which is of %-in. spruce. Chines are of spruce, % in. square, each in two lengths, running from stern to station 3, and from station 3 to bowpiece. They are screw-fastened to each rib and half rib, using 1%-in. No. 6 screws. Seats are of %-in. cedar, 12 in. wide, resting on, but not fastened to, spruce cleats, % by 2 in. in size, screw-fastened to ribs 2 and 3. The gunwales are of %e by 1%-in. spruce, notched in ribs at sheer line to receive planking. Inwales are also of spruce, 4% by 1% in. in dimensions, riveted to ribs and gunwales, as shown in the detail drawing. Battens are of “se by a |sbous. 4} ~- 1s be 4 ? ; - 2 , 1-1-8 SCREW 21 if SPRUCE + weed J) j--- a8 SCREW ; BOWPIECE ---- BOTTOM MEMBER OF RIB NO5 DECK SUPPORT STERN LAYOUT Layout of Stern, Showing Frame and Bracing; Right, Support for Canvas Deck, Which Extends over Forward Part of ull 1%-in. spruce. There are two each side and four on the bottom. Planking is of “-in. cedar on sides and bottom, screwed to ribs and half ribs and nailed (clinched) to battens, three planks on each side and six on bottom. The flooring is of *s-in. spruce; two pieces, 4 in. wide, run from. stern to station 3, spaced 2 in. apart, and one piece, 4 in. wide, runs from station 3 to station 7. All are nailed to the bottom members of the ribs. The sheer line , on extends 4 in. above the top of the ribs, and a %-in. half-round spruce molding is screwed to the outside of the planking at the sheer line as shown in the detail drawing. Glue all joints in the frame, also glue the planking to the battens, stern, keel and bowpiece, using Jeffrey's marine glue, C -quality. Keep all nails flush and putty all screw heads in planking. The frame is given one coat of good spar var- nish after assembly, and the planking one coat before fastening to the frame. After the planking is in place, the entire outside of the hull is given two coats of spar color varnish. A deck, made of No. 12 canvas, is fas- tened under the gunwales, extending from the bow to rib No. 5. It is supported at the center by the spruce stringer shown in the detail at the lower right-hand corner of the illustration on this page.

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POPULAR Hotbed on Porch Roof Here is a hotbed that will appeal to the small gardener or lover, as it is distinctly novel and has many useful fea- tures. It is located on the porch roof, flower Hotbed on Porch Roof Is Convenient and Out. of the Youngsters’ Reach . within easy reach from the windows, and is covered with a single sash, which is hinged at the lower side so that it can be raised conveniently, chains being used to prevent it from being opened too far. The bottom of the hotbed is covered with metal, and special shallow boxes, about 3 in. deep, fit in under the glass during the flowering Where such a hotbed should be south-sloping porch. The tion necessary is to see season. possible, placed on a only precau- that there is enough space between the glass and the bottom to provide room for shallow boxes and to give several inches of space for the growing plants. Such a hotbéd is al- so entirely out of reach of youngsters who often have the habit of taking flowers.— Dale R. Van Horn, Walton, Nebr. Kinks for the Auto Painter The auto,owner who attempts to paint his car for the first time will likely make the mistake of applying the varnish to the body of the car first. This is going at it The first step is to remove such parts as the hood and the headlight rims. These can be suspended from the ceiling and painted at any time. The backward. MECHANICS next step is to clean and dress the top and the upholstering, for, if this is done after the body is painted, you are sure to do a bad job, because a drop of top dress ing on a varnished surface will leave a mark that cannot be removed easily After the top has received attention, the inside fittings of the car, such as ing-post column and instrument brake and _ gear-shift should be painted and then the wheels and the chassis. For the outside of the body, which is painted last, a new brush should be used if best results are to be obtained and an old fine-tooth should be kept handy to smooth out the hairs of the brush as well as to steer board levers, comb remove any loose The above is a good way to re move dirt from the brush, as dipping it in gasoline might hairs. result in an uneven coat of paint. Blow the dust and dirt from the cracks and corners of the car with the tire pump before starting the job. This may prevent the finished job having that disgusting “stuccoed” which will be an eyesore to you as long as the job lasts.—Glen F. Still- well, Collinsville, [1. from appearance, Server for Butter Chips will be found two In small restaurants it convenient to bend the end prongs on an _ ordinary fork to make a butter server. The two prongs are bent backward and can be hooked over the edge of the bowl, as shown in the drawing, which makes the server readily accessible as well as sanitary. F. Minter, Mil- waukee, Wis. Handy Bag Holder To hold a bag in place while filling it with apples, vegetables, etc., drive four strong nails into the top of an empty barrel having both ends knocked out, and hang the bag inside of the barrel with the upper edge caught evenly on the four nails. The bag can easily be filled, the

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POPULAR MECHANICS yp unhooked from the nails and tied up, hile the barrel holds it. Remove the irrel and the bag is ready to be taken vay. If the contents are to be weighed, rst place the empty barrel and the sus- ended bag on the scales, fill the bag, lift the barrel and weigh the bag.—Mrs. \. K. Hinkley, Rowley, Mass. Cleaning Soiled Steel Engravings Many persons have old-style steel en- ravings that have become soiled through xposure to the dust and air. To clean hem, the following method will be found ffective and non-injurious to the print: Prepare a weak solution of chloride of me and carefully soak the éngraving in it until white. Then rinse thoroughly by n immersion in clean running water for everal minutes. Steep for half an hour in a flat enameled pan filled with water, n which has been dissolved just a little hyposulphite of Rinse again in clean water and dry between clean white blotters under pressure of weights, or in press. The result will be an engraving good as it was originally. soda. Baby Carrier for the Car When riding in the rear seat of a car it is quite difficult to hold a baby com- fortably, but by providing a carrier the trouble will be eliminated. The carrier hown in the drawing consists of a canvas hag, the open top of which is held rigid by a wood or metal frame. Lengths of brass or galvanized chain and springs, to serve as two coil hock absorbers, are attached as indicated, and the baby will be afe and comfortable. To prevent the crib from lurching, it should be fastened to the back of the front seat near the bottom by means of a short coil spring. SS —Carlton Groat, = The Dalles, Oreg. Simple Baby Carrier Hung behind Front Seat Is Safe and Comfortable Hand Spray Used Effectively for Moistening Clothes to Be Ironed Hand-Spray Clothes Sprinkler Clothes can be dampened for ironing with a small hand pump of the kind used to spray liquid for killing insects. Fill the container with water and proceed as illus- trated. The cloth will be moistened by an even distribution of water. Attaching Hose to Air Pump When attaching a rubber hose to an air pump rubber to the metal, to make the connectionair-tight. Heat the metal un- til it is quite hot, force the tubing on vulcanize the rubber and clamp it tightly for a few minutes. The rubber will be sof- tened by the heat and will adhere to the metal, making a much tighter nection than be had by using a clamp alone. If the metal is roughened with a coarse file. the rubber will stick still better. con- can

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668 POPULAR MECHANICS : gr ae SASS MS2ie3s2) 2 Large Wheels on Posts Make Adjustable Clothesline Supports Novel Adjustable Clothesline Two old hayrake wheels, mounted on posts from 20 to 50 ft. apart, maké useful, adjustable supports for a_ clothesline. \fter the clothes have been hung on the line, the wheels are turned one-half of a revolution to line. A bolt or hardwood pin is pushed into a hole drilled in each post, to hold the spokes of the wheel securely and prevent it from turn- ing. The wheels are approximately 5 ft. in diameter, which permits the line raise the to be raised so high that even long gar- ments will be out of the reach of dogs or children. The posts should be set firmly in the ground and the wheels attached by means of bolts run through the hubs. A large should be placed the end of the bolt to prevent it from be- ing pulled through the hub.—Dale R. Van Horn, Lincoin, Nebr washer over ALUMINUM ~ SEWED TO CURTAIN ) Ford Curtain Fasteners Ford tops and curtains can be repaired, if the cur- tain fasteners are torn out, by the use of a metal plate, preferably alumi- num, about 14% by 2 in. with the ends cut round © sbentover” and a small hole drilled in each corner. The fastener is mounted in the center of 7 HOLES the plate by drilling two holes for the prongs on the fastener and clinch ing them on the back side. The plate is sewed to the top, as shown, . with the fastener pro- i = jecting through the hole. aw ée.3? The sharp edges are filed ee down and the plate ‘ should be well sewed in place so that it will not shift and cut off the thread.—E. T. Gunder son, Jr., Humboldt, Ia. Remedy for a Rattling Gear-Shift Lever If the gear-shift lever on your car tends to vi brate and rattle the car is in motion, a simple remedy is as follows: Drill a small hole through the lever, about 2 in. above the floor boards or above the rotating joint in the the lever. Then fit spring around the lever, press the top end down until it is below the hole, and insert a long cotter pin through the lat- ter to hold the spring down. when base of a stiff spiral Reinstalling Shock Absorbers of the Strap Type With the shown in tool the drawing, it is an easy matter to re- and rein- strap-tvpe absorbers move stall shock without the la- borious process of lying on the oor and pulling the belt by hand. Thetool is made from a length of %-in. round stock, about 46 in. long, bent at right angles about 8 in. from one end. The other end is bent to form a hook, 2 in. In use, the inserted between the spokes of the wheel, as indicated, and around the strap; it is turned around to wind up the strap, which prevents it from going into dS long. tool is

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POPULAR MECHANICS e shock absorber. If disk wheels ed on the automobile, the tool is hooked er the strap in the opposite way, from e inside.—E. V. Willis, Springfield, Mass. are 669 Combination Garage and Summer House \ two-car garage on an lowa lake has been made to little summer house, where the family can sit and read serve aS a To Prevent Leaky Valves Leaky and improperly seated ilves are sometimes caused by imming or screwing them down o tight. Particularly in ad- usting carburetors, the novice iy make this mistake and ruin e valve. A valve or faucet hould not be forced, but should carefully and never lly closed when the valve seat warm. This also applies to a isoline blowtorch valve, for the mtraction of the seat and valve, ipon cooling, will ruin the lat- closed ter. Turn the torch down until nly a tiny blaze remains, and then blow this out. This will prevent jamming the valve, and as soon the torch the valve will be found to be snugly closed. cools, Flashlight Makes Red Lamp One photographer devised a satisfac- tory red lamp by using an ordinary hand flashlight. The lens was removed, the reflector blackened with India ink, hich can easily be washed off with water need be, and a piece of heavy photo- craphic film, which had been dipped in red dyeing solution such as is used for coloring electric lamps, was placed under the lens. The lamp is light and port- | The film can was Novel Summer House on Iowa Lake Built on Top of Garage Gives Better View of Landscape or look out the lake. Four con- crete pillars were built on top of the ga- rage, and a roof, floor and railing provided Aside from its great economy, the height of this summer house has the advantage over of giving a better view. Making an Emergency Windlass } The photo shows an improvised wind which is useful in an emergency. A the two rorce 1 to be applied. pipes held by the side of the rope, one vertical- I and a lass, secureiy to ob- the rods or rope is fastened between which Two heavy jects are ot} et ly and the horizontally, hitch is taken able. dyed other col- meet vary- ing conditions; a ors to certain shade of green, for instance, pan- films, light red or orange working with printing papers, etc. Ifavery deep red is desired, this can be obtained by for use with chromatic for around the two as shown. Consider- able force can be exerted by turning the horizontal rod, winding the rope around the vertical one. This method may be used to pull an auto out of a mud hole, if a tele- pole or a post phone sturdy fence using several thick- nesses of dyed film. Considerable Force Can Be provised Windlass Exerted with This Im- is handy for use as a “deadman.”

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POPULAR MECHANICS Roller on Basement Window Sill Prevents Ab- rasion on Rubber Hose Roller Guard Prevents Abrasion of Hose Needless rubber or fabric hose, caused by dragging it through base- abrasion of ment windows or other openings in build- ings, can be avoided by means of rollers, slipping n pipe over a and are both inside and outside the . and projecting a little above the If the construction of the opening through the building permits, be set in two drilled holes, which are made by a piece of ordinary ir rod, mounted window sills. the bar can while, if only aw indow -casing edge is available for sup- porting the roller, the ends of the center rod can be held by U-shaped clamps. Burglar-Proof Night Latch FILED It is possible ‘GROOVE to pry a sharp , blade the edge of a door and the jamb and open a night latch, but this will be impossible if a groove is filed across the edge of the tongue, as shown in the drawing. Should anyone attempt between FACING STRIP to insert a knife, the the groove and the tongue cannot be pushed back. Besides doing this, it i advisable to provide strips of sheet metal point will catch in on the edge of the door and jamb to pre vent the wood from being cut away at this point by thieves bent on gaining en trance.—Thos. H. Duffy, Juniata, Pa. Emergency Clock Key Having broken a clock key, an autoist took an old inner tube valve and made a new one. The U-piece and nut were left on to serve as a handle, but the core wa taken out. The square, pointed end of a file was driven into the open end, until it was expanded to fit the winding stem Skate keys can also be made in the same way.—Arthur Flinner, Manhattan, Kans Handy Chimney Ladder It is often difficult to reach high chim- neys and in case of a chimney fire this may lead to serious consequences. With this in mind, the caretaker of a church at Missouri Valley, Iowa, made a _ special ladder, which he bolted to the chimney. This installation is handy, as the chimney is of consider- able height and the steep that an ordinary lad- der could hard- ly be used, es- pecially dur- ing winter the roof is frequently covered with snow and ice. roof so when Homemade Fire Extinguisher A thoroughly dependable fire extin guisher can be made at little cost. Get a small acetylene-gas tank, such as is used to supply illumination Remove the and from the ends of the tank, then, with a rather stiff wire, bent to form a hook at one end, fish out the asbestos filler. ior motorcycles valve gauge This may seem a tedious job but keep at it until vou are sure every crumb is dislodged. A power-

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POPULAR MECHANICS stream of water from a hose iten will wash away large pieces. Vvhen the cylinder is thoroughly lean, get a large valve from a carded inner tube and thread e stem to fit the end from hich the pressure gauge was emoved. Into the other end, rew an ordinary brass valve of e type used to drain water from itomobile radiators, and, if you ish, a short length of copper or ss tubing may be soldered on this for a nozzle. Make sure hat the tank is air-tight, then uy a 5-lb. can of carbon tetra- hloride from the druggist, and our the contents into the pre- pared cylinder. Any of the tandard preparations sold to re- \| fire extinguishers may be used; ou will find carbon tetrachloride n excellent substitute. Then 0 to an auto-service station and pump the tank up to the highest pressure the service station com- pressor is set for. You need have no fear about doing this, as the tank is tested for 250-lb. pressure, so it will easily stand up to 100 pounds.—Walter Briggs, Poughkeepsie, N. Y. Safety Stop on Morris-Chair Back Rest Often, when it is least expected, the rod which is used to adjust the inclination of a chair back rest, will slip out of its notch, letting the back of the chair fall. This not only the furni- but may cause injury to the person who is about to seat him- self in the chair. A safety stop to prevent such accidents can be made by putting a screweye in the end of each rest support and stretching a piece of doubled picture wire between them, as shown in the illustration—K. M. Cogge- shall, Webster Groves, Mo. angle of \7T ° VLOTTIS - mars ture, SCREWEYE -- PICTURE ___ WIRE Quick Method of Cleaning Typewriter with Compressed-Air Spray Outfit and High-Test Gasoline Spray for Cleaning the Typewriter With the homemade apparatus shown in the photo a typewriter may be cleaned and dried in half an hour. A 12-in. length of %-in. copper tubing is flattened at one end, and a 5-in. piece, similarly flat- tened, is bent to form a blunt curve. The latter piece is soldered to the former, as shown in the detail, to form a double jet. A length of rubber tubing is pushed over the end of the short piece and the other end of the tubing is submerged in a jar containing high-test gasoline or other cleaning fluid. Attach the end of the other tube to a compressed-air line The strong spray will clean the typewriter quickly. After cleaning, the tube is removed and the air is used for drying. As gasoline fumes are highly inflammable one should keep away from any open flame while doing the cleaning. Warren E, Crabtree, Milton, Oreg. at a garage. @ Razor straps should be scraped and cleaned every month or so, to keep the leather from filling up with dirt; put a little soap suds on the strap when using it, to get good results.

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POPULAR Tool for Removing Lamps from Ceiling Fixtures a _ —=> AFR bd == When ting new lamps into fixtures attached to the ceiling, a put- ¢ step- ladder is usual- ly necessary. However, by rigging up the simple device the the lamps can eas- shown in drawing, ily be removed and replaced from the floor. It consists of a 5-ft. stick, to the end of which is at- tached a piece of corrugated cardboard, formed into a cylinder the inside diameter of which is a trifle less than the diameter of the lamp. To strengthen the holder it may be bound with tape. A few car- pet tacks are used to fasten it securely to the end of the stick. In use, the holder is pushed over the lamp to grip it firmly and by turning the stick the lamp can readily be put in or removed.—Henry J. Smith, Montreal, Can. _ 7 4 eRe Wiring Accessories to Storage Battery Frequently when connecting spotlights, horns, stop and other electrical devices to the storage battery of a car, the signals under nut of This however, wire is brought the terminal the battery. method is, rather as the unsatisfactory small corre des wire soon from the ac- tion of the sulphuric acid, and each the battery is nected it sary to disconnect the extra lead. A more sat- time discon- is also neces- isfactory way is shown in the illustration. The storage-battery cable is bared and the wire twisted around it and soldered. The joint is then taped and shellacked. This makes a durable and MECHANICS permanent connection, which will not b: affected by acid and does not interfer« with the easv removal of the battery.—G \. Luers, Washington, D. C Protection for Radiator Core Ford radiator cores, of the type used from 1917 to 1923, are often worn throug! on top by friction of the shell at the rear edge. It is important to keep the fabri: strip, which is threaded through the rea: edge of the shell, in good condition, and to replace it if it becomes hard or cut through in places. The reason for this that the fabric keeps the shell from wear ing the core and also prevents rattling and squeaking of the hood. Repair for Water-Pipe Leak If the water pipe springs a leak during the night or on Sunday, when plumber: are hard to locate, emergency repairs cat be made with a garden SEP RED hose WATER PIPE clip and a piece of rubber, cut from an old & inner tube, as shown in the The clip is that one of the met- al strips fits over the hole, PIECE OF drawing. RUBBER hose placed so otherwise the water pressure will stretcl the rubber until it bursts. Such a repatt while intended only as an remedy, may last for a long time.—Ivan E. Houk, Denver, Colo. emergenc\ Holes for Seat-Cover Fasteners The better grade seat covers are at- tached to closed cars with wood screws having ball heads for glove fasteners in the seat cover. An ordinary small twist drill should be used in drilling the small holes for starting the screwdriver slots in the heads are too small to allow them to be driven directly into the average wood frame. There i a layer of soft filling, much like cotton batting, under the upholstery cloth, and screws, as the

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POPULAR MECHANICS tarting the screws, the filling has a lency to catch on the drill and wrap ut it. This injures the upholstery and es the screws difficult to start. The should be drilled with a forward backward motion, one turn forward | a quarter turn back. The cotton will stick to the drill and vet the drill will ‘kly sunk into the wood.—E, T. Gun- son, Humboldt, Iowa. Homemade Snubbers Prove Effective in Stopping Rebound Rebound on rough roads is the greatest broken springs, and snubbers e usually provided to offset this action. the auto owner does not feel justified purchasing commercial snubbers, he se ot will be found en- Obtain two strong 1? i-_ n make some which ly satisfactory. prings, about in. long, made of Attach to the ends of each Ing a piece ot in. wire. ¥g-in. steel cable, long ugh to reach the front and rear axles, ving the pass over heavy evs attached securely to .the frame, | in the drawing. cable to iown Using cable mps, draw the cables up so tight that ‘springs of the car will be slightly com- The coil springs should be lo- ted in the center of the car just be- the running-board apron, and care ressed. uld be taken to get them in alinement. hese snubbers -will absorb side sways as as the vertical rebound of the car, —_ “iat lomemade Snubbers Absorb All Roads and Make Riding Comfortable Shocks on Rough nd the riding qualities of the auto will be und greatly improved.—Geo. G. Mc- icker, North Bend, Nebr. Cee eh et By ‘> eS - — ” Emergency Churn for Campers Made from Inner Tube and Sirup Pail Novel Improvised Churn While camping out last summer, a party of fishermen found their supply of butter exhausted, and vicini- ty could only furnish a jar of sour cream Taking this to a farm house in the camp, one of the party improvised a churn, which provided fresh He set the spring, cut a discarded inner tube at the valve butter in a very short time jar of cream in a near-by section a tree and that the a peg in the ground tied one end toa low branch of stretched the end could be tied to The tube receive a fitting lid. cover to was tube so opposite was then slit in the center to tight A hole was punched in the y-eal, sirup pail with a cork and the churn use. It was receive a ready for operated by grasping the inner tube above the pail and pulling it up or down, and letting it re bound. The cork was removed occasion- ally to allow the gas to escape. @ Registers are hard to clean with ordi nary brooms, or the like. and a method of cleaning them is to use stove polish on a rag: rood this enables vou to reach the corners and do a good job.

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POPULAR MECHANICS Making Picture Frames SAWED INTWO. SaweD Very good pic- aoe 2 ture frames can Ze Jeg be made from tongue-and- grooved lumber. Saw the lumber the desired width, measuring from the grooved edge. Cut away one side of the groove. Then plane the surfaces and fin- ish with fine sandpaper. This gives, a stock of picture-frame molding from which attractive frames can readily be made. ‘ picTuRE-” BACKING - Leaks Stopped with Bullets Recently an open-top water tank sprung a leak where the iron had been eaten rust. I tried soldering, but success, as the away by without bullet from a .32-caliber tridge rusted surface would not take the solder. The job was done in the following wav: A _ lead ) & ary. | Qe car- ——~ was in- |. LEAD BULLET serted into the hole, which was enlarged to receive it. A hammer head was held against the bullet on the inside of the tank and the portion of it protruding on the outside peened over with a riveting hammer as shown in the illustration. The repair shows promise of being a permanent one.—C. M. Wilcox, Torrington, Conn. Was Fire Hazard in Climbing Vines When chimney, vines are allowed to cover a which leads from a _ fireplace and touches a shingle roof, there is dan- get of fire. The vines, some of which become very dry, are easily set afire by a spark, and in one case the blaze spread to the roof. The result was that one side was damaged to such an extent it had to be entirely replaced and much more damage was caused by water. The vines should be trimmed every year and all the dry, dead branches should be cut off to reduce the fire hazard, and not lowed to climb to the top of the chimne —John E. Mason, Hamilton, Ont. Loose Coil Bridge Causes Spark Miss My Ford occasioned some trouble be- cause of a persistent miss that could n be located. The timer was examined; the plugs, coils and wiring and everything were found to be in good condition. T! compression and the valv were reground to insure proper seating but this did not cure the skip. On mechanic noticed that the coil bridg were loose due to improperly tighten: nuts and, of course, this did not pern a positive connection. As soon as the were tightened the car operated normal! —Glen F. Stillwell, Collinsville, Il. Was good Hookup for Using Doorbells on 110-Volt Lines When a doorbell is to be operated on 110-volt light line, it can be done | connecting two 32-cp. lamps in serie with the bell and the push _ button, shown in the accompanying diagra: Another way is to use only one 16-c; lamp instead of two and bridge the ty terminals of the bell with a 6 or 7-oh: resistance, an ordinary radio rheostat this capacity or any fixed resistance bei: suitable for this purpose. A resistance —9- about 7 oh can be ob 7 tained b ‘ winding abot 2 32-CP. OR 5 I6- 25 ft. of N “Taps oN © 21 Germar ff BELL silver wire 0 C; a piece ot fib: or bakelite taking cat that notw of the turns touch. The ordinary doo: bell will stand .1 amp. and requires volts’ pressure. So five 16-cp. lamp which have a resistance of 220-ohms eac! will bring 110 volts down to 2 volts an .1 ampere, LINE PUSH BUTTON ~_

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Of Ve:

NE of the beauties of ship-model mak- effect of the work, and besides, they ing as a hobby is that such splendid of course, can be used for doing all kinds can be obtained with a minimum of other work as well. tools and equipment. Many of us There is ordinarily a small sa e seen very fine models turned out by place, used for odd jobs, and irs during long watches below at sea, do quite well for the rougher no more tool equipment than a jack- cutting off stock, ete., when th and made of wood from old pack begun. If no saw is handy, cases, and the beautifully detailed maker will do wel lels made by French prisoners of war about 16 in. long gland during the Napoleonic strug- dovetail sav vere often made from the soup bones’ modeler’s kit; this is about their daily rations, their only tools, and has very fine teeth, about being their jackknives. However, inch. Even this will be le there is an element of interest in coarse for some work, and fact that a del has been under condi- the am- who to do good

as in other should ide him- with tools ecially pted for his iby. These }/ vit not many aa | tooth number, nor ( : is indispe re they ex- St om able, and nsive, but Ne , | coping saw, ev will add _— . , ith blades eatly to the : ; ; <a Bee | : for both wood se with : Be 3 . and metal, will hich the mod- also be found is construct- 2 ‘ a ‘ necessary sar. = — such the finished If the Model ‘Titer | ae Up His Own Hulls, Several Large lamps Are Essential cutting

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POPULAR MECHANICS est size of these should be purcha One model maker fashions his own s1 chisels from \%-in. drill rod, grinding end down and sometimes bending it, suit the shape of edge he requires, driving on a handle made from a@ piece dowel rod. A good spokeshave is an dispensable part of the tool equipm« this may eit! 1 be of the wo f en type, wl | the writer a fers, or one v a metal body The Hacksaw with the Tube Back Is a Very Useful Homemade Tool, Also the Drill- Rod Chisel Which May Be Made in Any Shape shape, and oper- fF YeY 22g ations of a simi- FROM DRILL ROD lar nature. There are two stvles of the latter tool used by model mak- ers; one is the ordinary coping saw, and the other is the jewelers’ saw. The latter is the smaller of the two, and is thus easier to handle on some work, but the ordinary coping saw will answer the pur- pose just as well for ordinary work. Chisels and other cutting tools are the next consideration. There should be at least one good-sized chisel in the tool very good form, although a little m kit, one about 1 in. wide. The best form expensive than the ordinary, is a patter is the beveled-edge socket chisel, and a makers’ spokeshave, which can be adju paring gouge of similar size should also’ ed for either straight or curved worl be obtained. The smaller chisels, %, “4 the job in hand may require. and %-in., and three gouges of similar A smoothing plane, while. a_ hat width, may be of the “butt” or pocket thing to have around, is not essenti type, with a blade about 3 or 3% in. long. since the stock can usually be obtain These short chisels will be found ex- surfaced at the mill, but a small blo: ceedingly handy. For fine work, and for plane, about 3% in. long, is quite nec« reaching into places inaccessible by means’ sary. These are very cheap; in fact, ! of the ordinary straight chisel, some bent planes of this size can be obtained at carving tools will be found, if not essen- five and ten-cent stores which are go: tial, at least very useful. One maker puts enough, provided the blade is kept shat up small carving tools in sets of six, with and this is necessary with all cutti a variety of cutting edges, and the small- tools, regardless of their quality. The

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the dow el. POPULAR MECHANICS small tool used in making musical uments, called a thumb plane, which valuable one. The body of this is held between the thumb and fore- r, and the “handle” butts against the of the hand. In case the reader iot buy one of these tools, a drawing iven so that he can make it himself. body is preferably of beech; although hardwood with a fine, close n will do, and is made in two parts, rward doweled and glued together, convenience in cutting and filing the slot and wedge seat. The handle short piece of dowel rod, with a hard- “1 knob on the end. The knob may slice from a broomstick, rounded on and drilled on the bottom for the end The blade may be ground ery sood m a piece of hacksaw, or made from lar steel. The bottom of the plane be flat, concave or convex, for dif- rent work, and the cutting edge of the tte should ttom rtant tting ter all, is ( to suit. The project more than a and honed not the the le ground ir’ from of ne. im the tools ‘ the knife. he most of mble he shape of rs not handle mat- in the t, nor the t of the tool, SMOOTH PLANE HALF OF ™ PLANE BLOCK BLOCK PLANE ° 45° ; ] fe W {CUTTER <7 ams - o j ff . 4 y = 677 provided the blade will take and hold a good edge. A couple of “sloyd” knives, of different sizes, are also handy, but | prefer a blade somewhat concave along its length, instead of convex as a sloyd knife is; however, that is a of taste. Quite good carving can made from broken ground to shape and honed to a keen edge; the simplest form of handle these is made by wrapping lavers of tape around the end. No matter what the of a cutting tool may be, the satisfaction it will give depends entirely on the care given the edge, since no tool is better than its cut ting edge. matter knives blades, be hacksaw tor cost Keep the oilstone constantly at hand and give the edge a few licks TSE] TWO TYPES OF SPOKE SHAVES At the Lower Left , SS Are Detailed Drawings for Making a ““Thumb Plane,” in Case the Reader Cannot Buy This Useful Tool in a the ed. pt Y . lar this “ WEDGE THUMB PLANE once as ver V much hetter than work when they are allowed to become comparatively dull before they are sharpened. finish the edges, In sharpening the carving tools, after honing, on a razor strop, as these tools must have the very best edge obtainable, if clean cuts are to be made. Next to his cutting tools, the modeler’s best friends

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678 POPULAR MECHANICS ADZE-EYE TACK ) rd HAMMER 2 it GOOD SHAPE OF ZF ~~ KNIFE BLADE BRAD HAMMER ofoe's!: ¢ SPRING >), CLOTHESPIN SY a = | HAND SCREW The Pin Vise and the Homemade Clothespin Clamps Are Indispensable in Gluing and Drilling Small Parts; the Knife Blade Will Also Be Found More Useful When Honed to the Shape Shown are his files. A 10 or 12-in. flat or half- round bastard file will remove a surpris- ing amount of wood from a rough hull in a short time, and there is not nearly the danger of cutting too deeply that there is with a drawknife or chisel. It may not be good woodworking practice to use a file on work of this kind, but the SMALL DRILL AND DRILL SET maker should not let that In addition to the large flat | 6-in. pillar, triangular, square, and rou files should be in the kit; the pillar, rou and square files should be bastard-cu' and the triangular one a second-cut; ordinary saw file is fine. These will found exceedingly handy when maki: model him. Worl TO THE MASTER OF THE GOODE SHIPPE “HALVE MAEN”: Dear Captain: And now we have come to the end of the few months of shipbuilding under your masterly direc- tion, months which should have found a grown man and a father at other things, no doubt, than bruis- ing his fingers and cutting his mitts with planes and drawshaves, gluing the whole cellar from laundry to dog’s bed with liquid cows’ toenails, extracting slivers like fence rails, cussing in three languages (including Seneca Indian), when my compass steered me wrong in figuring out plans and specifications so clear that my young son could read them, but which, to me, were like the third declension of the irregular verb in Sanscrit; but at last, Captain, she stands on ’er ways as slick an’ trim as the blue- eyed barmaid of the Purple Boar tavern, an’—shiver my timbers!—I’m proud of ’er! The hours spent with my boy and dog while do- ing your delightful ship have been so very much worth while in the feeling of companionship and understanding which has come to the boy and me as a result of our mutual interest in this ship and its making, I find double return for any trouble and labor. That alone is pay enough, indeed, but that is not all, for we have learned many things that were mysteries; the way of ships, the meaning of many strange salty terms and expressions which fascinate boys and old boys as long as they live, and the knowing and understanding of which give a new flavor to tales of the sea. Lanyard, crow’s nest, gammoning, belaying pin, lubber’s hole, crow- foot—they meant nothing to us before, but now, when we read of a sailor on the foretop’s’!] yard. we see that tar and know he isn’t down ir the foc’s’le . . . . The busy professional man like myself I advise, without charge, that he take his boy and his tools, go down to the cellar with those copies of P. «M. and learn many worthy things. It will teach him patience, perseverance—and his boy, and when he has "er done, and the lady of his heart who dwells upstairs pats her two boys on the head and says, “It really looks just. like the pictures Mr. Miller made of his ship; put it on that table near the window,”’ he’ll feel so darned proud and so thrilled with the feeling of having seen the thing through that he'll no doubt do just what I have already done—start two more.—Dr. E. W. Flagg, Auburn, N. Y.

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parts, especially by the man who not any too sure of his controi over ill chisels. In addition to these, a set needle files should be obtained. These ed no handles, and come in seven or ht different shapes; if these cannot be , tained easily, get die sinkers’ files. The ter are somewhat similar to the needle but are used with small handles. kon't use a rasp instead of the large igh file; the latter will take off almost much stock in the same time as the », but will leave the work in much tter shape for subsequent operations. \s for drills, about the largest ever d for model work is % in., and one h of the “4, % and %-in. sizes should be all that is necessary in the fractional ves. In the wire sizes, the worker should uv a set numbered from 1 to 60, and a ple each of the No. 65, 70, 75 and To hold the drills, one of the mall hand drills sold for radio work is leal, except for the 34 and ™%-in. drills. For the small drills, from No. 60 up, and hen drilling delicate work, such as fut- ick holes in crosstrees, get a pin vise m a jewelers’ supply house, fasten a in it, and drill the hole by twirling he vise with thumb and forefinger. h hammer round the house, and for the infrequent asions on S sizes. ere will usually be a claw which a large hammer is necessary this will serve nicely. There far more occasion for small Get an 8-oz. ball-peen ham- 5-oz. hammer and a 7 /-OZ. hammer with a long nose and several mmers. er, a tack lve eve vy, somewhat like an upholsterers’ ham- er, and you will be well equipped. hese need not be expensive, since the ork they are called on to do is very rht. The writer has some hammers of the kind mentioned that only ten ents a piece, and has been using them with satisfaction. the miscellaneous that ill be tound handy around the bench are good square, with at least an 8-in. blade, a pair of good small tweezers, a hook, and a number of small lamps. The crochet hook seems rather peculiar “tool,” but it will be found ery rigging. Among the lamps should be several sizes of small - ©-clamps; also, if possible, at least two, cost tor vears Among tools n awl, rochet handy in POPULAR MECHANICS 679 opening 6 in., known as carriage clamps, and two regular wood clamps. If you can get a cabinetmaker to glue up your hulls, the large clamps will not be neces- sary, but the small clamps are essential. Very good clamps for light work can be made from ordinary spring clothespins, the jaws being cut into several different shapes to suit the work. The individual can add to this stock as he progresses and finds that he one or more tools of a size not specified. There are some tools not mentioned that may be preferred for some modelers, needs certain work by such as a drawknife, and, of course, one needs an oilstone and oil slips for sharpening chisels, gouges, etc., as well as sandpaper of different grades for finishing work. Safety Fence Prevents Railroad Accidents railroads close to reduce In many towns run buildings, and to the number of /4 s f4 Fence at the Bottom of Stairway Minimizes the Risk of Railroad Accidents accidents, a safety fence of the kind shown in the will be found When coming down the stairs behind the drawing effective. building a person may not hear or see an approaching train, and unless there is some barrier, he is apt to walk from the steps directly onto the track. A railing, about 3 or 4 ft. high, can be built at the bottom so that a person descending the steps is compelled to follow the route indicated by the arrows, which gives him time and op- portunity to see whether or not the track is clear.—J. S. Hagans, Chicago, Ill.

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680 Protection for Chicks in Brooder Coop Brooder coops for chicks are usually made by nailing lath at intervals across the opening of This however, neces- sitates the use of screens or boards a box. to close the openings to exclude rats and mice, and prevent the chicks getting out early in the morn- ing. To over- come the ex- tra trouble of propping boards or against coo p Ss young from too screen the every evening is a simple matter if a few minutes more are spent at the time the coops are made. Strips of lath are cut to fit between the top and bottom of the open front of the coop, and nails are driven at the points indicated to serve as pivots upon which the lath can turn in the same manner as window shutters. A length of wire is bent to a loop at each lath and staples are used to-attach the wire as shown. By moving the wire back and forth the shut- ters of the coop can be opened or closed. No large door is necessary at the front, as the coop is bottomless. This permits the removal of the mother hen when necessary to move or clean the coop.— G. E, Hendrickson, Argyle, Wis. Equalizing Rear-Wheel Traction Owing to the differential action of au- tomobile rear wheels, the driver is some- times at a loss what to do when stuck in a muddy or sandy rut. The trouble is that one wheel provides traction and the other one does not. In many cases one could easily get out without being hauled out by some one, if only the traction of the rear wheels were equalized. This can be done by simply pulling the emergency POPULAR MECHANICS brake back just far enough to drag o) both wheels, which will make them wor: evenly. This is only of use, howeve: where the emergency brake operates o: the rear wheels, and is of no value whe: it operates on the transmission.—E, k Haan, Chicago. Hint on Varnishing In varnishing, the worst trouble is the collection of dust on the treated surface Any amateur painter can do a good jol however, by observing the following d rections: First, a new brush should bh used and this be cleaned by tapping it on the palm of the hand to romove loos bristles and dust; then scald the brush ir boiling water to soften it and finally let it soak in gasoline for about two hours after sandpapering the article to be vai nished, the surface is carefully cleane with a rag. Then apply the varnish an let it dry hard. Dust that collects afte: varnishing may be removed with a paste of pumicestone and oil rubbed with piece of heavy felt. A fine job will result Homemade Colonial Candle Holders Decorative candle holders of the colo nial type are easy to make and cost ve little. They consist of a flat piece oi bronze or sheet iron about Me in. thick cut to a diamond shape, as indicated, and bent at right angles, with small collat to hold the candle. Thi forge mark are produce by hammer ing it irregu ——— 244— l larly, hold / 4 ‘ J ‘ SLOTS FOR / \ ing the ham SECURING // U1’ wet ‘sitictat! COUAR G44 tilted. To |} match the © holder, the BEND ~ y/ x %! ¥ A‘ SLOT FOR ; Soy head of a HANGING’ large nail i flattened and hammered square. It is driven into the wall so that the holder can be slipped o1 easily —G,. A. Luers, Washington, D. C

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POPULAR MECHANICS ‘How to Remove a Stuck Rag from Gun Barrel \ rag that has become lodged small-caliber rifle barrel dur- a cleaning operation may removed in the follow- Measure the gun bar- and get a piece of stiff wire a tle over half its length after has been made for a one end. Fashion and irpen the other end like a cro- hook, so that it will easily ‘rece the cloth wedged in the e. Ifthe end of the cloth can- be reached, get another piece wire and split the end with a sel instead of making a single int. Sharpen these ends and ike a few nicks in the ends of th with the punch so that the re will cling to the rag when he wire is twisted. No matter ow firmly the rag sticks, the agged edges will get such a good old that it can be pulled out. lv be way: owance p at Clock-Spring Towel Clip Towel clips can be made in a few mo- ents from pieces of old clock or phono- craph springs, as shown in the illustra- tion. One straightened and drilled to receive two or three small wood screws, with which it is fastened to a wooden base. The other end is turned over as shown,so that when a towel is pushed under it, the spring will grip it secure- but still allow it to be pulled away.— lk. A. Goering, Langenburg, Can. end is Lines Guide Underwater Swimmers When several persons dive at once for in underwater swimming race, they are likely to collide and interfere with each other because of their inability to see the course clearly. This trouble was over- come at one club by marking white guide 681 re Lengths of White Tape Serve as Guide Lines in Underwater Swim- ming Contest lines at the bottom of the pool. A num- ber of lengths of white tape, of the kind used in marking tennis courts, were pro vided, each being as long as the course. Heavy lead fishline sinkers were fastened to the tape at intervals of 6 or 8 ft. and the tape laid along the bottom in a straight line from the starting to the fin- ishing line. The tapes spaced far enough apart to prevent interference.— L. B. Robbins, Harwich, Mass. are Arranging Piston Rings Although it is a well-known practice to stagger the ends of piston rings so that the joints are not in piston .JOWNTS line, the attention of RIN 4 the amateur should be called to this most im- portant detail of as- sembly, when overhaul- ing his motor. When slipping the piston back in place, take care that the ends of the are not above rings : PISTON PIN each other for by such an arrangement loss of compression would be sure to G. C. Douglas, Raleigh, N. C. follow.—

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An Effective Ignition Intensifier By THOS. W. BENSON .—" problem of intensifying the igni- tion spark of internal-combustion en- gines has interested many inventors, judging from the numerous makes of in- tensifiers that have been placed on the market. Almost without exception they BAKELITE TUBE-, A Compact Single-Unit Ignition Intensifier That Has Proved Very Effec- (3 3X BRASS TUBE hence to the piug also, the characteristi: of the spark are completely changed. The system becomes a tuned oscillating ci: cuit, and when the breaker points open the condenser is charged and discharge across the plug a number of times wit! great rapidity. Therefore, instead of on spark, the charge in the cylinder is sub jected to a rapid series of sparks, giving more intense This change i readily noticed by running the engine wit! one plug out of its cylinder, when th: spark, instead of being thin and purplis! in color, is thicker and nearly white ignition. | Practically an | GROUNDED \\ \ TO CHORE 5 INTENSIFIER | a condenser an * | inductance would serve the purpose, but the writer arrangement ol! COIL believe the device is re DISTRIBUTOR _ ETHOD OF CONNECTING F 8 a 43x 1g BRASS TUBE tive over a Test Period of Eight Months ‘~ COPPER -WIRE COIL CROSS-SECTIONAL VIEW OF INTENSIFIER have been of the series-gap type, and have had their limitations. The sidered the problem from a different viewpoint and devised an intensifier that has proved very efficient. writer con- The principle of operation may be un- derstood from a study of drawings A and B, particularly by those acquainted with the old spark transmitters used in radio telegraphy. The ignition equipment on all cars using a breaker and distributor gives one spark across the gap each time the -breaker points open. Such an ar- rangement is shown diagrammatically at A. Now, bv connecting a condenser across the coil and an inductance in series with the lead to the distributor, and 682 duced to its simplest form by construct ing it as shown in the detail drawing Kxact dimensions need not be adhered to, but are given for guidance. The oute shell is a 4%-in. length of 1%-in. brass tubing. The ends of this tube are slot ted with a hacksaw for a distance of ™% in. so they can be bent in to hold the as sembly together. Inside the shell is 4-in. piece of fiber or bakelite tubing, |! in. in outside diameter with a ! wall. The inside plate of the condense: is a 3%-in. length of brass tubing, hav ing an outside diameter of % in. The large fiber washers used in the ends are % in. in diameter and the smaller % in The writer used regular spigot washers 16-10

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POPULAR the purpose. The inductance is made closely winding No. 14 to 18 cotton- ered copper wire on a %-in. mandrel With the ve parts on hand and two brass ma- ne screws and nuts for terminals, the 113i til a coil 3 in. long is made. embly can be started. First slip the inductance inside the aller brass tube, and solder one end of to the inside of the tube or fasten by eans of a sare the wire back the soldering and wrap it around the ead of the screw to be used at the left- nd terminal as shown; then assemble e two washers on the screw and bolt up echt. The brass tube with the inductance side is then slipped into the fiber tube nd positioned about midway of its ength. The free end of the inductance an then be pulled out, and the other terminal, with its insulating washers, at- ched. It is well to identify the termi- that is connected to both the induc- ince and the inner brass tube with a pen- mark or file scratch, so the device will e connected properly into the circuit. rhe final step of assembly is to inclose e whole in the outer brass tube. Pre- pare the outer shell by slotting the ends ra distance of % in., spacing the slots in. apart around the tube. Bend in e strips thus formed at one end of the ibe. The fiber tube should now be ipped into place, the smaller washer on he terminal extending out beyond the bent end strips of the tube. The strips it the other end of the tube are then bent over to hold the whole device together. The method of connecting between the coil and distributor is shown in one of the mall drawings. Take that the marked terminal, screw. care MECHANICS Kink for the Fisherman If your fishing rod is the cause of sore ribs, provide a leather disk on the end of the handle as shown in the photo. The Leather Disk Attached to Serve to Prevent Fishing-Rod Handle Will Sore Ribs disk can be cut fron’ a piece of sole leath- er and is tacked or screwed to the front end of the handle—Andrew R. Boone, San Diego, Calif. Smoking Set from Auto Parts A novel and handy smoking set made from various parts of discarded cars. was The cigar holder is a piece of the steer- ing post and the end of a coil, and the monogram on it taken from a fra- diator cap. A _ resistance-unit box was used to make the calendar The ashtray is an old piston and the feet are balls taken from a bearing. The pen rack and pin tray are made from an old piston and the pen holder from an old line and a spark-plug cap, while the letter opener is formed from the handle windshield Was holder. Yas of a connected to. in- ductance and inner indicated the illus- tration, is connect- ed to the coil. A bracket holds the device on the en- grounds rnonths’ and Cm gine and it. Eight test has proved that it will fire any plug that is not ‘short- circuited. Novel Smoking Tray and Writing Outfit Made from Old Auto Parts cleaner and a hood bolt. A brass dash plate and a radiator flange were used to the a water-inlet tube splash-pan | make inkwell. whil and a dash-lamp bracket matchbox the The base on which these parts stand is part of an old alumi- num door. made

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684 POPULAR Drain for Yard Hydrant To prevent mud puddles around a yard hydrant, the drain shown in the photo has been found quite practical. A sewer drain, or sink, is in- stalled direct- ly under the hydrant, be- ing sunk about 1 ft. in- to the ground, and a large tile is slipped over both. A lid will make a good stand when filling buckets. Safe Razor-Blade Holder The problem of disposing of used safe- ty-razor blades so that small chrldren can- not get hold of them = ;>>~__ may be solved by cut- ;y>% ting a slot in the lid of |/ an ordinary tobacco tin and soldering the = puny. é SLOT lid shut. This will --goLpenen hold about a — year’s accumula- ~- TOBACCO t TiN tion of blades and can then be thrown away without endan- gering anyone. Jerky Speedometer Shows Lack of Oil Most speedometers are driven from the transmission, and, on several popular cars, the driving gear and worm are lubricated from the universal joint. The speedometer should accelerate smoothly with the car, but occasionally it will seem to catch and swing from the correct posi- tion, registering from five to ten miles fast at each oscillation, especially when the car is being driven fast. Investiga- tion of a number of cases revealed that it was not the speedometer drive which was at fault but that the grease was entirely MECHANICS gone from the universal joint due to neg lect, and the friction of the gears driy ing the speedometer was sufficient t cause the jerking. Repacking the joint with grease restored the even movement of the speedometer, not to mention the benefit to the uwniversal-joint bearings. Simple Way o* Regi ating a Clock When a clock is going too fast and the adjustment pin is at the extreme end oi the slot toward the slow position, or vice versa, proceed to adjust the clock in the following way: Remove the back of the case and you will notice two little curb pins on each side of the hairspring. These are for the purpose of controlling the ex pansion of the spring. Open these slight lv and then move the regulator back to ward the middle of the slot. This ad justment should slow the movement down slightly and the regulation can then -be made in the regular manner by the adjust ment pin. Pressing these pins together slightly but not enough to bind ihe spring will have a tendency to increase the speed. Be careful, however, in making the alterations, as a slight opening o1 closing will be all that is necessary. Crimping Stovepipe When house-cleaning time comes and the kitchen stovepipes are taken apart for a thorough cleaning, it often happens that they do not fit s «gly when again put together. This would make it necessar\ to crimp the ends with a tinner’s tool, but as this is not usually a part of the home equipment, a substi > tute must be provid- Y ed. A simple method ' de VM whe is shown in the il lustration. An old w Ny / J ¥/ J fork, a ham- d ~~. merandasmall Sy \ bpd rE { \ block of wood % — ANVIL ihe 1UCK Is used as an anvil and the prongs of the fork are pushed over and under the edge of the pipe, as shown, so that light tap ping of the hammer will make the crimps in the pipe.

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All Shop Notes published in 1926, in book form—Fifty Cents—from our Book Department How to Buy and Keep Your Paintbrushes By T. M. JAMES Ppeweney is probably no tool that the problem; the average man is usually con handy man around the house uses more’ tent merely to wash out the brush he has han the paintbrush—nor one that he just finished using in turpentine and put nows less about. He knows, of course, it to one side, with the feeling that he hat there are good and bad brushes, but has done about all that is necessary. The hat constitutes a good brush is a com- consequence is that the next time he needs the tool, he finds it almost useless. If it was a good, and consequently an expensive, brush in the first instance, this hits him in the pocketbook, in addition to the annovance experienced by finding the brush unequal to the job. If it is a cheap brush, it might just as well be thrown away. We will not speak of the habit of simply leaving the brush in the paint for weeks or months, or of putting the brush to one side without even cleaning. Everyone Alt} ehh 1 in i HH Ii | WHI wl HAL SHAPE OF RROPERLY HOW BRUSH FLARES MADE BRUSH FLAG END HOG BRISTLE WITH SINGLE-LENGTH BRISTLES Drawings Show Poi- . How the Brushes Should Be Look *e . 4 . Wrapped for Storage Se Aepaens ie > knows at tl average householder. = shouldn't be done, and [n addition, the tee mean t everyone has experi matter of keeping = ." enced the consequences brushes in good con- - * at one time or another. dition throughout Er The most important the year remains a imap part entering into the 685

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686 of a brush is hog. bristle. There is no other material that is as good as this for paintbrushes. construction Hog bristle is horny and elastic and has excellent wear- ing qualities, and besides this, the peculiar formation of the ends of the bristles ren- ders them particularly good for the pur- pose. An examination of the bristle un- the microscope shows that it has a hard, horny outer shell, composed of mi- nute scales, and a softer pith in the cen- ter; it is a little larger in diameter at the root than at the tip, and at the “business” end it branches out into ends, called the “flag” one of the illustrations. This end really forms a small brush in itself, and is what enables a brush to carry a load of paint well. der smaller end, as shown in several This characteristic is also largely due to the fact that hog bristles are barbed for their entire length. The most common substitute for bristle in inferior brushes is horsehair. This has not the flag end found in the bristle, and besides, has not the elasticity and is not barbed like bristle, and consequently it will not carry the same amount of paint. A properly made brush is built up of bris- tles of lengths. several [f the bristles were all of one length, POPULAR MECHANICS “toppy.” When the flag ends of the bris tles have worn down, a brush of this type will spatter paint and “leak,” the painter calls it. A brush with graduated lengths of bristles, on the other hand, will wear for a long time, without any tend ency to these faults. As the flag eng of the longest bristles wear out, those of the next length come into use, and as these wear, the next length, and so on, the brush retaining its painting qualities until it is worn practically down to the ferrule. The most important things to observe when buying a brush are the following The should straight and springy. as good bristles be clean should and should long, The brush feel well-balanced in the hand, present a trim, well-made appearance. ven with a certain amount of familiar ity with the requirements of a good brush, it is rather difficult for the ama- teur to be sure that he is getting the best value for his money. The best one can give, aside from the foregoing is to pay a good price for the tool, select only those made by a well-known manutacturer and to avoid cheap brush- es, made by an unknown maker as one would the advice et the brush would = plague. With havea decided brushes, as SS inti | For Window Trim, Use a ger ye yd | ad Flat or Oval Sash Brush flare at the ends. i | with the tools of It is a common | all other © skilled error of the ama- | |' trades, it is poor teur to buy a brush | 2 J economy to buy because it seems | | cheap articles “full,” when, as a | which, in the end, matter of fact, it | prove dear at any may contain too | — price. The main much horsehair, b : : FLAT SASH BRUSH ~ factor in the life and merely be EEE RaEEE Te of a brush—given

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POPULAR MECHANICS —— BRUSH HUNG IN OIL of od bristles—is eir length. It is vious that the nger the bristles, rovided the brush properly made and t toppy, the more ear will be ob- ned from it. The manner’ of setting e bristles is a matter of judgment on he part of the maker, and the buyer eed have no prejudice in behalf of any rticular method. 3rushes with bris- set in glue, cement or rubber are all erfectly satisfactory, if made by a good ker, while brushes that appear to be in the same manner, but selling at a price and not backed by the name of reliable manufacturer, may be useless, ue to the shedding of the hairs. \s to the type of brush that is best for rious painting jobs around the house, almost as many ere are painters. Some prefer the flat. etal-bound type; others, will ve nothing but the leather-bound flat tucco brush. Many painters prefer the der type of round and oval brushes for rge surfaces. All are and the hoice depends to some extent on what irt of the country the reader is located There is one thing that should be ken into at is the ere are opinions as again, good, consideration, however, and size of the brush Where irge surfaces are to be painted, a 4-in. brush will do the job in a quicker and more Satisfactory manner than a 3-in. one, and if a new brush is to be pur- chased, the larger size should be bought lor a job of this kind. For the average mall-wall job, such as a bathroom or }} i ieee S-GAL.OIL CAN, CUT DOWN OIL LEVEL-, jk Above, Two Simple Good Brush Keepers; low, Brushes Must Be Thor- oughly Washed before Put- ting Them Away hall, where time for the amateur is not a great consideration, a 3%-in. wall brush will be found some- what easier to han- dle than the 4-in., yet not quite so time- consuming as the 3-in. size. The bristles should be from 3 to 4 in. long. For painting small work, such as trim and window sash, etc., either a flat or an oval brush should be purchased. Flat brushes commonly used are the 1, 1% and 2-in. sizes, and the bristles should be from 2 to 2% in. long are made from % to 15 sash The oval brushes @ in. wide and with bristles ranging from_about 1% to 2% in. in length. There is not much choice be- tween the two types. The flat tools will cover the surface quicker than the oval, but the latter, on the other hand, are preferred by many painters for fine work. The flat varnish brush is the tool for the amateur. This brush is very similar to the flat brush, but has a shorter handle, and is made in much greater variety. It is made from 1 to 4 in and with bristles sash wide, from 1% to 4 in. long. For varnishing floors or other large sut faces, the 3-in. will be found the suitable, and the 1 to 1'4-in. size for trim and small work. The best grades are made of size most French bristles or Chinese black bristles of suitable length white and good elasticity. The varnish brushes used for flowing coats on fine furniture, for flowing on fine enamels, finishing automobiles. ete.., form another class that will not be dis- cussed here, Should the reader have ox

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688 POPULAR these brushes, he will be well advised to present his prob- casion to use one of lem to a good paint store, and be guided by their advice. One would not think of buying a good chisel and allowing it to lie around to be- come rusty and dull during the intervals between use, and vet many men think they do their full duty by a good brush when they stick it, full of the paint just used, in a pail of water. A brush should never, under any circumstances, be stored in water. When a brush is plunged into water, it soaks it up like a sponge, and the next time the brush is dipped in paint or varnish the water is hog-bristle sealed in. The consequence is a _ soft, flabby brush, with twisted and unruly bristles, which cannot do good work. Brushes should be cleaned immediately after use. If the job has not been fin- ished, and the brush is to be used in the same paint next dav or evening, put the brush in a pot of linseed oil overnight. Don’t stand the brush in the pot. Hang it. Drill a hole through the handle to take a stiff wire that will extend from side to side of the pot, and so that the ends of the bristles will be at least bottom of the pot. % in. above the If several brushes are to be kept in the same pot, wire hooks can be made to hold them; but don't stand them. Brushes stood on end, no matter in what liquid, will bunch out and curl up at the ends, good, easy work. and then—good-by, Another good scheme is simply to use a piece of hardwood across the top of the Into each edge of the wood strip drive a number of screw- hooks and hang the brushes on them. See that the oil in which the brushes are kept comes well up to but not over the ferrule. When the brushes cannot be stored in an oil bath, work as much paint as possible pot. out of them on a clean board, then wipe them well with old and finally wash out all the paint—every bit of it— in gasoline, benzine or kerosene. Straight- en out the bristles and lay the brush on its side until it is dry. Varnish brushes, or rags, brushes used in enamel, mav also be suspended in the oil pot overnight, but be sure to wipe the brush free from the oil before using it in the varnish again. It is really better to store varnish brushes overnight in the MECHANICS varnish can, in which they have been use: but this would mean leaving the ca) open, and a skin forms on the top, whi must be removed completely before tl] varnish is used again. keeping varnish is sold by paint stor for this purpose, but the amateur’s vai nish jobs are so few that it pay to obtain this. When cleaning vai nish brushes, use only turpentine, ar lay them out flat to dry. Brushes used for aluminum, gold a1 other “bronze” A special brus] W ould not lacquers may be washe out in alcohol, benzine or this should be they are used. also be gasoline, at done immediately afte Shellac brushes washed out in ately after use. shoul alcohol immedi These are quite often kept in the shellac pot, and this is fairly sati factory if the pot has a close-fitting li through which the brush is tightly fitted but if the top of the pot is open, the fer rule and the bristles around it “seedy” from the shellac, which harder between the bristles and afterward flak: off and gets all over the work. If the brushes are not to be used for long time, washed, become they should be with thorough! turpentine, gas: va alcohol, line or benzine as the case may be, previously directed, taking care that thi bristles are thoroughly cleaned right up to the ferrules, then wrapped with paper to keep dust and dirt out, and tied wit string and laid away flat. Store them o: a shelf in a cool room, and place a fe mothballs around Moths will la eggs in the bristles, hence the precautio All this may seem a lot of work, but really takes much less time to do than t describe, and, as none but them. good brushe should be purchased, if the user wants t do decent work, and good brushes co money, it is really worth while to care fo them, not to mention the time when the next painting job comes along Say ed Soldering and Brazing Nichrome While in the research department of a large concern manufacturing electric heating appliances, I was called upon t: devise a method of welding tacts to nichrome ribbon. brass con Nichrome is a hard material to solder or braze, but thi difficulty is overcome by fusing borax at

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POPULAR MECHANICS 689 e point where the joint is to be made. e part is then cooled and the fused borax ocked off. This leaves a clean surface the nichrome to which the solder or zing compound will adhere. Nichrome re or ribbon treated as above can be idered nicely in this way—Wm. Hop- e, Sunland, Calif. Preventing Movement of Shifter Handle Some machines having a fast-and-loose lley countershaft occasionally start up themselves, which in many cases is ngerous. The trouble can be prevented a simple manner on machines that do t need to be stopped or started often. ike a piece of round stock for a weight drive a length of rod into it. Upset | flatten the other end of the rod and ike a stud to fit on the end of the shifter indle. This is slotted and drilled to re- ceive the flattened end of the rod, which held by means of a pin, and is tightened ith a nut. When the handle is moved » the on position, the weight is swung round to the center as shown, and this movement is reversed for the off posi- tion. Thus the handle is prevented from orking in either direction. The device would be useless in the case of a machine that has to be stopped and started con- tantly, but many of the modern ma- chines are controlled by a clutch below, the handle only being used to start the clutch pulley. It is to a machine of this pe that this safety device applies. PIN = eT | * ROD? — oe (O*\ ¢ | J . ‘ = oh ——_—_—-, WEIGHT’ SHIFTER —> OFF ~~ a ON ROD Ba iia’ STUD’ l ) __ J WEIGHT ulety Device for Shifter Handle That Prevents Ma- chine from Starting Too Easily Piston-Ring Compressor Where no speciai tools are available tor the purpose.a piston-ring compressor made Effective Method of Compressing Piston Rings with Length of Baling Wire from a length of stovepipe or baling wire and a metal rod or hardwood stick will be found very effective. A loop is made at each end, one end is slipped over a stud driven into the block, the wire is wrapped around the piston ring and the other loop over the rod. Using the latter as a lever, the wire is pulled tight and the ring will be squeezed into place.—Luther Stro- | snider, Onaga. Kans How to Proofread Mimeograph Stencii One of the stenographers in a New York office discovered a convenient meth 1 | od of proofreading mimeograph “dry stencils. Instead of holding the stencil up to the light to read, or inking an im pression, which makes it necessary to clean the stencil in case a correction has to be made, she places a thin sheet of ber sheet and the paper between the fi backing. These new drv_ stencils have a coating of blue wax, which leaves the color on the sheet under pressure of the tvpe. Thus the entire copv is printed in ue wax on the sheet inserted between the fiber and the backing.

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690 Precast Units for Retaining Wall Provide Strength and Drainage Much of the cost involved in erecting concrete retaining walls for embankments along highways is in the installation and New Type of Con- crete Wall, Used on Highways to Prevent Earth Em- bankments from Washing Out or Breaking Down over the Road, Is Built Up of Slabs, Which Provide Strength and Insure Proper Drainage removal of the forms. too, it be- pro- In some cases, comes necessary to vide adequate drainage. Now and then, when a solid con- crete wall is cast under these con- ditions, the tremendous force exerted on the wall is sufficient to fracture it. This involves expense and sometimes One steep embank- more necessitates renewal. ment on a main highway leading out of Omaha, Nebr., is faced with a novel and wholly satisfactory wall built up of units, as shown in the drawing. The face rails are 8 ft. long, with inter- locking joints at the ends, and of the shown. They are held in place concrete section by means of tie-rod slabs, which have a special head to interlock with the face slabs. As a rule, the tie-rod slabs are about 8 ft. long to insure proper an- chorage for the whole wall and about 12 in. square at the ends, the body is about 6 in. square, but may vary in One distinct this tvpe of wall is that the slabs can be pre- while leneth. advantage of where raw materials are convenient and during spare time. plenty of flexibility to suit any road condition, cast There is POPULAR MECHANICS and as the face of the wall is open, surplus moisture drains off without dar age. No mortar is used in making the walls. The concrete used is a_ 1-to mixture of cement and gravel. Steel r: intorcing rods, four in number, are la FACE RAIL in each unit, the ends being bent at rig! angles to add greater strength.—Dale R Van Horn, Walton, Nebr. Interior Painting Intezior painting is rather expensi) and there are many who do their best cut expenses when building a home. T these it will be of interest to know that Georgia pine, which is much used for terior trim, can be well covered with on! two coats of paint before applving th necessarv finishing coats of enamel. [1 other words, two coats of paint are elim inated and much labor saved, as it usu ally takes from three to four undercoat properly sanded, to do the work in th: ordinarv wav. In the simpler method a mixture of seven parts pure linseed oi! and one part pure pine tar is used for 1

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ie ee POPULAR MECHANICS 691 ming coat. This must be rubbed in with a brush. When dry, apply a of pure white lead, thinned with raw eed oil, with very little drier, and to idd just enough good lampblack to e it a slightly gray tint. Brush out econd coat well so that all chances blistering will be eliminated. The im is then ready for the enamel coating, the grain will not show.—L. H. orger. Buffalo, N. Y. Testing Length of Rubber Bumpers Rubber bumpers on the door frame of ed cars sometimes require adjustment ‘ause thev do not touch the door when sed. This is due either to wear on blocks, or warping of the door or rame. As several rubber blocks are used 1 each door it is difficult to see which touching the door when closed. A rip of tough paper held at one end from he inside of the door and projecting out- ird over a rubber block and between the loor and the frame will show if it is touch- ng the door when closed. If the paper be removed easily after the door is osed the rubber block is too short. Non-Skid Loading Plate Sheet-iron plates used for loading from ttiorms to freight cars, or vice versa, ten become slippery, and are a fruitful urce of accidents. A good method of Ty? roving the plate is to weld onto its urface a number of short “ribs,” as shown the photo. They are built up by us- elding rods and an acetylene torch. 4 bs Welded on Surface of Loading Plate Prevent Trucks from Skidding on It Staple-Driving Tool Driving staples is usually a rather awk- ward task, but with the holder shown in STAPLE SPLIT- Staple Driver Made from Bolt and Piece of Metal Tub- ing Saves Time and Sore Fingers the illustration it becomes easy, saving time and sore fingers. It consists of a piece of metal tubing, flattened at one end to receive the staple, and a punch made from a bolt, which can pe slid up and down in the tube. The head of the bolt is cut off and the end flattened and ground to fit inside the lower end of the tubing, while the threaded portion pro jects beyond the upper end to receive a small coil spring and a nut. The use of the tool is obvious. Casting Oil Grooves in Bearings When pouring bearings, for example the main bearings in a cylinder block. a perfect oil groove can be made by laving in short pieces of match stems of the de- sired length before the babbitt is poured. A piece of metal is sometimes used for this, but it is difficult to remove, while the wood burns away almost entirely, leaving a good groove —R. M. Shelton, Dallas, Tex.

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692 POPULAR Easy Method of Oil- ing Overhead Shafts with Oilcan At- tached to Long Pole Oiling Overhead Shafts We found it annoying, while oiling overhead shafts, to carry a ladder, espe- cially when there was quite a bit of ma- chinery around. mechanic the problem by attaching to the end of a 10-ft. pole. as shown in the drawing, One solved a pump oilcan A bent spout, permitted the worker to drop the oil from above the shaft. Tle oilcan was attached to the pole by means of two pieces of strap iron, bent to fit around the oilcan and the pole and MECHANICS can. When in use, the pole is held in « hand and the lower end steadied agai the body, while the cord is pulled with 1 other hand to discharge the oil.—L. J. F gel, Chicago, III. Holder for Bendix-Cover Screws The Ford bendix cover must someti: be replaced when no special tool is hand for holding the four small scre The gasket should be prepared by s! lacking one side and dusting the ot! side with graphite or tire mica. It is stu in place on the transmission cover w the graphite side out. be removed later, on If the cover mu the gasket will rem the transmission cover and be un jured. The on the next motor are started and the cover replace the slotted holes in the cover lowing the edge to be moved under t! heads of the screws. The upper and low: screws are easily placed and a holder ma of small wire is used to start the scr: next to the frame of the car. screws side Screw The hold is made by wrapping one end of a pie of fine wire around the body of the ser: When starting the screw, it is lower from above with one hand and held at t right place while the screwdriver is u with the other hand. When the sc: well started, the wire is pulled off EK. T. Gunderson, Jr., Humboldt, Iowa is e e Triangular Gluing Table Triples Outpu' A manufacturer of pianos has solved t problem of the producti on one operation, increasing with a W-in. flat portion between, which was drilled fora screw. A short | lever [ a strip Ye6-in. stock pivoted to the upper end of the pole, indi- cated. A _ hole is drilled in one end of the lever to per- mit the attachment of a cord, which is pulled down to ac- made of and was ot as the same amount space by providi a three-sided g! ing table of the ty shown in the phot It consists of a t! angular framewo upon which tl! sides are fasten: and is supported « a shaft in the cent so that a workm can turn and the lock it with any o1 tuate the pump plunger on the oil- Triangular Gluing Table Rotates on a and Triples Output of its three sides Horizontal Shaft the top. ;

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ie all farms are provided with cur- buy a large Ford timi:

sed for a few dollars

Battery Charging with the Farm Engine By L. B. ROBBINS ng gear, and be rent from the public mains or from — sure the pinion on the generator shaft is own lighting plant. It is therefore included. First fit the timing gear to essarv for the owners to take car, the crankshaft of the engine. This ck and radio batteries to town to some should be on the wheel turning clock- ging station when they become low wise, and is usually on the right-hand lischarged. Practically every farm of side of the engine, although this depends size, however, does possess a gasoline on the type. It may be necessary to ne for pumping, ensilage cutting and bore out the shaft hole in the gear and ‘ral work, and where such an engine enlarge the keyway to fit the shaft. If f 3 hp. or more, and fastened toa solid so, be sure to center it perfectly, then ndation, it can easily be used for bat- drive it on so it fits near the end of the charging without altering it in the shaft, as indicated in the drawing. t. Engines vary so much in design, \ wooden frame should then be as ind minor details that specific di- sembled after the design shown. This ons cannot be given to suit all tvpes, consists of two upright pieces of 2 by the general idea in this article can be 6-in. stuff, which are mortised and bolted

rked out by anyone to suit his own’ toa horizontal base of the same material ine. Just carry out the principles of Set the uprights back a few inches from design, and you will have no trouble one end, and bolt a slanting brace be- 1e construc- f ML ce. ccc ccc. ccnnccicn ag, tween them ot of this sim- | —_ | any suitable ieee FF +-- ENGINE FLYWHEEL (RIGHT-HAND, FACING ENGINE) A ua. , equipment. I 14 neavy wood. in dime 4 || ,-TIMING*GEAR ee ee Che ini | | le rear ens S | PINION 4 . . cic < ‘ | _ CORSISES Of | FORD GENERATOR AMMETER =| | ord genera- | ‘ F | Jour jT-OUT ‘Ss --+--WOOD FRAME , PLATE + +—-—¥ [ HINGE -~, t " } FLOOR, —S-—s; L

Above, the Wiring Dia- gram for the Charging Outfit; Below, the Gen- erator Is Driven from the End of the Shaft That Runs Clockwise which can be pur- any dealer in used-car parts.

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694 POPULAR of this should be beveled for bolting to the the other end. The tops of the brace and the uprights are then cut out to fit the curve of the generator. base at CURVE TO FIT GENERATOR ————}ie Next make a genera- an tor plate of sheet steel, in the detail. The pinion end of the generator, should project through the hole, and be bolted to the plate ex- actly as in the in the car. The end of the plate as shown casting bottom is bolted to the vertical sides of the uprights and brace, as shown, so that the body of the generator rests in the curved timbers provided for it. With the generator in place on the plate, it should be further secured by a metal strap, fitting about it and bolted to the sides of the uprights. Arrange a block on the floor so that, when the rear end of the frame is hinged to it, the base will be exactly level, the generator pinion engaged with the tim- ing gear on the engine and directly un- derneath it. An arrangement must then be made so the height can be raised or lowered to provide the right backlash between the gears. This is shown in de- tail, and consists of a steel plate bolted to the top of the base and a second plate bolted to the floor. A round steel rod, threaded nearly its entire length, screwed through a hole tapped in the upper.plate. It turns freely in a larger hole in the floor plate, where it is held from moving lengthways by a shoulder and flange, or by a pair of small collars, above and below this plate. The rod is bent at right angles at the ton for a han- dle. Then a guide iron should be bolted is MECHANICS to the floor to moving sidewise. prevent the base fi This is simply a pic of flat steel bolted to the floor, each « being bent up at right angles to just cl the edges of the base. Connect one wire to the generat plate and to the negative pole of the b tery. The positive wire should then connected to the cut-out terminal and the positive battery terminal, ammeter inserted shown, to with indi as the’ rate of charging, although this ca: be dispensed with if desired. Details of Generator Mounting and Fitting for Dise gaging Drive When Generator Is Not Wanted The height adjuster serves to low: the pinion from the gear when the ge erator is not to be used. This is nec« sary when no charging is to be done, | cause running the generator without battery in the line will soon burn out windings. So, when through chargi1 simply turn the handle of the adjust rod to lower the free end of the ba which disengages the pinion and allo the engine to run free. Then, when battery is to be charged, simply reve: the process until the pinion and gear r engage properly. Keep the gears we greased and oil the pinion end of t generator shaft and the cup at the oth: Such a charging outfit will serve to ke: all the 6 to 8-volt storage batteries to scratch” and, by using a high chargi rate, this can be done in a few hou while the power pulley at the opposi' end of the shaft is doing other work.

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POPULAR MECHANICS emporary Repair for Broken Shaft Made with Tubing hen a line shaft breaks, or any shaft is well exposed, a temporary repair be made with a short piece of heavy Choose as long a piece of pipe as ractical to use and with an inside di- ter as near to that of the shafting as ble. Drill two or three holes through ipe on each side of the center. These s should be staggered. Tap them for vy setscrews, slip the pipe over the ken ends of the shafting and take up the screws until the shafting is held se- ely. If the pipe is slightly larger than hafting, make a shim to take up the k all around before assembling.—L. B. bbins, Harwich, Mass.

Traffic Signal for Motor Trucks with Inclosed Cabs ‘or trucks having closed cabs, a traffic il of the kind shown will be found | | | ‘ee . e. aes oo es ; ul. it consists of a wooden arm, pis Filling Water-Conduit Tunnel from Above with Lean at one end on the front of the cab Concrete through a Six-Inch Spout os : : ee aie — -. ‘ itted at the other with a stuffed, Safe Method of Backfilling Tunnel te glove. A strong cord is run through hole in the front of the cab above the The drawing shows a safe method il arm. and a knob tied to the end. backfilling a water-conduit tunnel, used 41 hen a left turn is about to be made, the by a western contractor. Rather than is pulled and the white glove will backfill with earth, which would necessi into plain sight to the left of the tate the dangerous work of pulling as indicated in the illustration—E. timbers, he leaves the latter in place Gunderson, Jr., Humboldt, Iowa. fills the tunnels with lean concrete. concrete is mixed on the ground poured into the tunnel, a vertical di of 10 to 30 ft., through 6-in. well which are sunk at 25-ft. intervals then shoveled into place Cement Hog Wallow Uses Old Oil

A Nebraska farmer had some mat left over after building a concrete dation and utilized this in making wallow. pil 1 . 1 When Making Left Turns =‘! Winter Oi! OMly Is Used,

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696 Windshieid Frame Makes Sign Mount A discarded auto - wind- shield frame makes a good mounting for & sign, as shown in the illustration. While the glass itself can be used to paint the sign on, thin wood may be substituted. The standards which support the sign are lengths of ordinary pipe. Be- sides being novel, the sign is very cheap. —L. I. Thomas, Oak Park, II. two Hose Nozzle Made from Pipe Fittings In many industrial plants, mills and factories, it is customary to provide hose connections for conveniently washing floors, vats, etc. A cheap and easily made nozzle is shown in the drawing. It is simply a short nipple of the proper size inserted in the end of the hose and held in place by a hose clamp. On the other end of the nipple is screwed a common pipe cap, in the center of which has been drilled a hole, “4 to *% in. in diameter, depending upon the size of the This nozzle delivers a strong, solid stream, which is most effective for washing purposes.—Les- lie G. Roller, Cedar Rapids, Lowa. ;HOSE CLAMP /NIPPLE “4 HOLE hose. Keeping Your Brakes in Order One seldom feels the need of brakes until that nerve-racking moment when even four of them do not seem enough, and .because such moments are becoming more common as traffic congestion is get- ting worse, it is a good plan to look over the brakes each week. This is a job that the auto should do himself, for there is probably no one who knows the state of efficiency of the brakes better owner POPULAR MECHANICS than he, and no one will give them clo attention. A mechanic may reline ; adjust them properly, but the everyd care is usually left to the owner. Before attempting any adjustment of a brake, « should study its action from the le back to the drums. If the mechanism carefully examined, a great many unoil joints will be found that may cause tr: ble. The rusty clevis pins should be oil and all threaded portions of adjusti: rods should be protected from rust by application of oil or grease. Trouble adjusting them is thus prevented. O casionally the brake cams freeze and, when this happens, an e: way of freeing it is to apply a mixture lubricating oil and kerosene and oper the brake until the cam loosens up. T! oil will eventually work its way to t! corroded point and end the trouble. Av: spilling an excessive amount of the mi ture on the brake lining, as this will pi vent the brake from working. This mir ture can be used to advantage in lub: cating all the brake mechanism. one of Gauge for Setting Calipers in Wood Turning In turning a number of wooden artic each having several different diameter it is very troublesome to use a rule set the calipers for each diameter. overcome this difficulty, a wooden turned down to different diameters, be found handy. If the gauge is mark: to correspond to the diameters, there \ be no confusion in setting the calipers gaug Wrench for Union Nuts on Small Pip An open-end wrench frequently is us: for tightening nuts on the joints unions, of pipes, on END VIEW sma aut: trucks, tracto and engin¢ for the fuel or « ing systems. A gas improvement ov« the open-e! wrench, will not alwa fit these unio: is a socket wren w hi

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POPULAR MECHANICS the type shown in the drawing. A slit cut in the side, just wide enough to pass er the pipe in the fuel or oil system. A will serve as a turning lever or tommy. e tool steel pipe, by forging e end to grip the nut, size is not can be made a standard ailable. Hotbed Is Built over Brooder House Last spring I built an <tension to the south our brooder arranged it as to hotbed irectly above. The ex- tension built 2 ft. ide and as long as the brooder house, which as 8 ft. This addition was covered with boards, resting on 2 by 4-in. joists, and he hotbed built over this. The armth from the room gave the plants an early start and prevented their freez- ng, although several times the tempera- ture was as low as 20 degrees.—Geo. G. \IcVicker, North Bend, Nebr. de of and have a ouse was was Strap for Clamping Tapered Work Tapered work is very difficult to hold down on a machine table, and as an or- dinary flat strap, bearing on the does not clamp it securely, it is custom- ary to the vork between sup- ports at the back and traps bearing on the This requires a time, there- shop has the special strap shown in the illustration. The same wedg- ing effect is obtained with this ingle strap as with the straps supporting pieces. It is, moreover, much handier and preferable in all cases where a top strap is not objectionable. —Harry Moore, Montreal, Can. edge, W ed ge tapering part. method vreat deal of however, and fore one devised and WUT ---.4 SOLT +... WORK ---—» PACKING ——------ Simple Strap Used to Hold Tapered Work on Machine Table 697 Tires Protect Pavement from Mower When traversing paved streets in town or the highways in the country with farm Old Tires Slipped over Wheels of Farm Implements Protect Soft Pavements and Road Surfaces from Injury implements having wheels provided with cleats or studs, such as mowers, consid- erable injury often results to the street surface, especially if it is soft, as asphalt. It is often necessary to load these imple ments on trucks or wagons to transport them in order to prevent A better and simpler remedy) trouble is to slip some old tire over the wheels, as shown in the If the wheels are tire, two casings are cut damage. the casings such for photo. large for a single and too lipped on, the section not covered by one tire being covered by a section of another. It will, of course, be necessary to wire short sections of tire to t The 1 } ie wheel. natural shape of the single tire will keep it on the wheel Herbert Eustis, securely. C. McKay “4 9 Florida. @ Sometimes it is de- sired to decorate the walls of a house where the plaster is cracked; most own- ers use wallpaper, but better results will if build

be obtained, ing paper is applied better still,

first or, canvas.

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POPULAR MECHANICS Weeks Truing Inside of Flanged Brake Drum, with the Wheel Attached Close-Up of Job at Right, Showing the Type of Tool and Arbor Used Truing Brake Turning Inside of Truck- Drum on a Wheel Brake Drum; Work Chain- Drive Is Done on Gap-Bed Lathe, Truck Wheel Using Raising Blocks under Head and Tailstocks Where Drum Is Too Hard to Turn, Grinding Attache ment Is Used Photos Courtesy So, Bend Lathe Works

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ELE RS NT: a tes Ce Bet ee POPULAR MECHANICS 699 Keeping Truck Brakes Efficient Lack of trueness in brake drums may re- iit from various causes, such as accidents, edging of small abjects between the rum and the bands, and so on. In any se, to provide proper braking action, he drums must run true and be perfectly ound. One untrue drum may cause brake rabbing, skidding and other troubles. lo true a brake drum properly, it should he turned or ground while attached to the vheel on which it is used. This is not lways possible, but the drum _ should ever be removed from the wheel if it can e avoided, as rebolting it is almost sure spring it out of round or warp it in ome way. Not only should the drum e left attached to the wheel, but the vheel should be mounted or an arbor and wung on lathe centers while the truing operation is done. The ideal type of athe for this work is a gap-bed lathe, which has part of the bed next to the headstock removable, so that work of a much larger diameter than the lathe will ormally take can be placed in it. Addi- tional swing may be obtained by using pecially made blocks for raising the head ind tailstocks of the lathe a few inches. In some cases, bus or passenger-car wheels may be mounted in the lathe on their own axles, but usually it is better to employ a special mandrel. Where an occasional drum is found too hard to turn, it is trued by the use of a grinding attachment, substituted for the toolpost of the lathe —Avery E. Granville, Cleveland, Ohio. Drilling Mica When cutting or drilling holes in mica or bakelite, the tool often breaks through and leaves a ragged and torn edge. To prevent this trouble, take two boards with smooth, flat surfaces and clamp the material be- tween them, as shown in the illus- tration, using C- clamps to hold the three to- gether. The pieces of wood should be cut the same size as the bakelite or mica and all the edges should be in alinement, so that the template can be used on the wood. In the case of bakelite, it is only necessary to clamp a piece of wood below the work, as the drill only leaves a ragged edge on the underside. Portable Workbench for the Garage Most auto mechanics like to have a full issortment of tools at hand where they can be reached without going from the vorkbench to the toolroom or to a wall rack. A sturdy bench, which is portable and can be pulled up beside the car on vhich the work is done, is a great con- venience. The photo shows a workbench and tool tray of,this type. he bench is made of 2-in. material and has a lower shelf for holding cans of oe See. ae ; Handy, Portable Workbench for the Auto Mechanic hellac, oil and some Holds Full Assortment of Tools of the heavier tools. The top has two sloping sides, which make a tray for con- taining the tools, so that they will not roll off when the bench is moved from place to place. The legs of the bench are mounted on casters to facilitate shifting to any part of the shop. At night, it can be pushed into the tool room and locked up without removing the tools. if desired, a heavy vise can be mounted at one end. @ Hard-rubber balls and old golf balls make good stoppers for washbowls or laundry tubs.

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MECHANICS Canvas Strips Pro- tect Load of Tiles Carrying Tiles on Wheelbarrow When similar and other wheelbarrow the tiles, brick material on a moving edges are likely to be chipped or other- this is often used between the layers. wise damaged, and for reason straw Straw, however, is not always available, so one builder uses pieces of canvas, one end of which is tacked to the vertical rest of the barrow, as shown in the detail. The pieces are laid between the layers of tile and prevent breakage and chipping. Pick for Snapping Chalkline . Sign painters, sidewalk artists others who employ a chalk- line in laving out their work usual- ly find it difficult to stretch the line with both hands and at the same time snap it. To overcome this difficulty, a Wisconsin sign artist and uses the simple little pick shown in the illus- tration. A piece of fairly heavy tin is cut to the shape shown and the ends are bent to form a ring that will fit snug! over the tip of the index finger. Whe stretching the line, it is held in the usu except that the finger of the right hand one end leaving the forefinger free to use thy pick.—G,. E. Hendrickson, Argyle, Wis. way thumb and secor grasp Fillng Holes in Castings The following formula is for use when holes in iron castings must be filled for appearance’ sake, and where strength i not a factor: Sulphur, 50 parts; filings, 20 parts; fine iro1 graphite, 20 parts; al by weight and powdered. The powder when mixed, is placed in the holes an melted with a hot iron—Maynard Bod ley, St. Paul, Minn. How to Count Cards Quickly When it is necessary to find the nun ber of cards or sheets of paper in a which would probably take a few hour to count in the customary way, a quick, rough estimate can be made by counting a small stack, about 4% in. high, and then measuring the whole pile. In this manner you will find how many stacks are equivalent to the large one, and a simple multi- plication gives you the number of cards or sheets in the latter—Julius Duncan, New Orleans. La small CARDS IN LARGE PILE Countershaft Mounted on Auto Springs A clever method of mounting a sma! countershaft was shown to me by a loca machinist when he pointed out a support consisting of two cast-off auto spring The springs were bo'ted to the timber and the bearings fitted with bushings to accommodate the coun tershaft. Then they were slightly spread overhead were

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POPULAR MECHANICS the belting arranged to the machines. the belting stretched, the tension of automatically took up the B, Robbins, Harwich, Mass. springs ck.—L, Starting Joints in Old Piping Old steam or water pipes that are be- taken down often offer difficulty at : joints where turned into fittings. Too uch twist will either split the pipe or soil the fitting. A _ better when her methods fail, is to apply quick and tense heat to the fitting to expand it uddenly. This can be done by pouring ladleful of hot lead over the fitting in mall, rapid stream, allowing it to col- ct in a suitable dish below so that it can returned to the pot before it hardens. he sudden application of heat will ex- nd the fitting and the threads can usu- ly be started immediately after the ouring has been done. way, Keyway-Cutting Plane For cutting keyways on small shafts, he tool shown here will be found quite timesaver compared with a file and hisel. It is made of a piece of hard- ood for the body, about 1% or 1% in. ick, 2% in. high and 12 in. long. The key way -cut- ting tools are “ by % in. r larger. Oneisused start the ut and the ther to fin- h it. Back- ng irons are the plane body to upport the its, and a iron, % by 3 n. long and made as hown, is used with the thumbnut to ieed the bit into the work. A very light cut should be made at each stroke of the plane-—Geo. H. Cappel, Wilmer, Ala. et into CUTTING --—-- TOOLS} piece of "by -handle of Safe Knife-Switch Thrower Open knife switches in factories can be mounted near the ceiling and controlled with a length of sash cord, as shown in the drawing. The switch is mounted on a board which is held verti- cally by means of braces at- tached to the joists. A length of rope is tied to the the switch and is passed over two small pulleys at- tached to the joists on either side of the switch. A knot is tied in the rope a few inches below the pulleys, to prevent pull- ing one end out of reach. Repair for Loose Tail-Lamp Socket The socket in Ford tail lamps, up to 1925, is soldered to the body of the lamps and projects below it for the plug. The soldered joint is necessary to ground the current and, if it is broken, the light flickers and goes out. Tools for solder- ing are not often at hand when this occurs, but an emergency repair can be made by wrapping a small wire around the socket below the body of the lamp. The other end of the wire is pulled tight and tied to the frame of the car. This will keep a steady sidewise pull on the socket and hold it in contact with the body of the lamp, thus grounding the current and keeping the lamp lighted until the con- nection can be soldered. @t is difficult to remove insulation from the heavy used in with a knife, but can be placed upon a stone or some other hard surface, a hammer will flatten and break the toughest insulation so that it can be peeled with the fingers. wire outdoor wiring if the ends of the wires few blows

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702 POPULAR Door Keeps Chickens Out of Hog House , : ’ qaoot ror the LOY A sectional, hanging house, as shown in the drawing, will keep Keeping Chickens Out of Hog House with Hanging Door Sectional chickens out and does not Cut a 6-in. board in width of the door. Two holes 1inder the hogs ndet gs. engths equa in the ends of enc] be wired together as shown.—El]mer Raithala, Minn. in the doorway Floodw ood, Making a V-Type Fan Belt It became necessary some time ago to The than | a new V-type fan belt for my car. was $3, which was more wanted to pay, so I proceeded to make result was better than antici- pated, the belt was and the cost one. The entirely satisfactory was less than 50 cents. I obtained enough scrap sole leather at a shoe-repair shop to make it, and 50 cop- per rivets. The V-shaped pieces were cut COPPER = out as indicated in the RIVETS -.. aes drawing, all pieces be- ing made as_ nearly alike as possible and then riveted together. After riveting, the belt was placed in a vise and the sides planed make a smooth The flat side of the belt was also dressed down ] aown to surface MECHANICS a little, care being taken in doing this n the rivet heads \. S. Jamiesor Mass. to strike Springfield, Magnet Tool Replaces Spring in Valve Grinding If the valve-grinding tool used whe automobile usual overhauling an engine magnetized, the 1 spring under tl ve head may be dispensed with, sim the valve will be lifted with the too Most garages have a coil for remagneti: and the end of tl grinding tool can be magnetized in thi ing magneto magnets, How to Drive Small Screws in Deep Slots In the absence of a magnetized screw litte with a spring clasp for holding the scre one is “up against it” when driving a smal driver or the commercial article in an awkward place, such a Here is a very to do the iob, Take a narrow . cloth twice the i the screw driver. in its center button- than ] 1 engthwise like a hole. the diameter of the , 1 a ilittie longer screw head. Slip CO™ STRIP through this slit and hold it in place on the end of the screwdriver by means of the cloth shown in the screw strip, as the illus- tration. The screw may then easily b slipped in place and the cloth pulled of after the screw has taken hold—Har1 D. Tiemann, Madison, Wis. To Free Spring Bolt of Hard Grease When the grease hole in a bolt is drille lengthwise, the old, hardened grease ma that th will do its work be loosened and started out so pressure lubricator this method, making the removal of t!] bott unnecessary. Take off the pressure lubricator fitting and get rod, stiff wire or even a nail squared at the end, that .will just slide in the a short piece (

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POPULAR MECHANICS e hole. Start it into the hole a short ince and give it a sharp blow with a mer. The resulting pressure inside of bolt will be so great that, in almost ry case, when the fitting is replaced pressure applied as usual with the ricator, the grease will enter and spread lily—Sherwood J. Gee, Salt Lake Utah. ead Content of Tin Easily Determined lt is sometimes necessary to determine lead content of tin. This can be done follows: Make a solution of potassium romate in water. Apply a few drops of etic acid to the tin which is to be ex- ined, and a white coating will appear. ply a few drops of the potassium- romate solution to the white coating |, if the spot turns yellow, the tin con- ns lead, and the more yellow it appears e more lead it contains.—L. H. Georger, uffalo, N. Y. Trick for Cleaning Drain Pipe It is quite difficult to clean out a side pe of a drain with a hose, as the end of e hose will not enter the branch. This theulty can be overcome by removing he nozzle and doubling one end of the se, as indicated in the drawing, using a th to push it ick to the side ipe, upon ching which e folded end ill snap into it. ordinary es of clean- ng the long ‘rizontal drain pes, the noz- e is left on the se, which is ushed up and ulled back everal times, with the water turned on, intil the obstruction is removed.—M. W. wry, Athens, Ga. Wooden Jack Reaches under Axles Conveniently Quick-Acting Auto Jack When changing tires on a car bumpers, it is unhandy to use a short- handled jack. Several makes of jacks, with long handles and low-lift positions, are obtainable on the market but a good, wooden jack, which is just as effective, can be made as shown in the drawing, and will proxe very serviceable, especially for garage use. A length of 2 by 4-in. wood is fitted at one end with a U-shaped bracket or clip, made from a piece of flat iron. About 1 ft. from the end, a short section of 2 by 4-in. stock is securely fastened by means of heavy angle brackets. On the end, a T-shaped support is hinged and a small coil spring is attached to keep it pulled forward. A fastened to the bottom of the T-support to pull it back. The handle end is planed round for convenience in handling. To use the jack, keep the T-support back by means with cord is of the cord, slip the U-clip under the axle, then bear down on the handle. As as the axle been the cord, and let on the support. soon raised the has sufficiently, release axle down IN accordance with the editorial policy of this magazine never to accept compensation in any form for what appears in our reading pages, and also to avoid the appearance of doing so, we are obliged to omit P the maker or the seller of any article described. will be furnished free, by addressing Bureau of Information, the name o This information, however, is kept on file and Popular Mechanics Magazine, Chicago,

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x ill House Service Bureau

Is This Your Home?

Plan No. 5D32

UESTIONS Small Ho regarding home building addr yuse Service Bureau of the Uni ited tects and endorsed by the United States de Blueprints, specifications and close self-addressed envelope for a 24-1 sample plans. A new booklet, bureau houses actually lived in, tained f 20 cents tamped cnethess for reply. If entitled

essed to this magazine will be answered by The Architects’ States, yartment of commerce. material list for the house shown here may be obtained Inc., controlled by the American Institute of Archi- Inclose 10c and self-addressed envelope. at nominal cost. In- further send 5c and stamped information is desired, age booklet explaining how the Small House Service Bureau functions and showing ,12 ‘Fifty Ways to Lower Home Building Costs,” and showing how as much as $1,000 can be saved < illustrated by ten on a home, may be ob-

HE ted here is a illustra house typical American bungalow of five rooms. One of the major problems of ‘anv one- story dwelling of more than four rooms is to obtain proper ventilation. Inevi- tablv, since there are only four corners, some of the rooms cannot be lighted on more than one side unless there are ex- pensive offsets in the plan. This diffi- culty has been overcome by equipping the kitchen with a complete wall of win dows. In addition, it opens upon the rear entry way in such a manner as to pro vide two more wide openings for proper ventilation. There are two bedrooms, each with a large closet. From the rear hallwav rises the stairway to the attic and access is had through this hall to the bath and kitchen. The living room. dining room and kitchen are arranged much as they would be in a two-story house. The living room is provided with a doorway at the side of the fireplace for entry into the garden. The fireplace it- self dominates the living room. It may

704

side by windows located such a positior that people sitting about it are not di turbed those passing from the bule to the dining The exterior of be flanked on either desired. It is by vest room. the house is characte ized by the charm and simplicity of the homes of our forefathers built during the Colonial period. The combination « plan and exterior is simple, honest an characteristic of the be American builder straightforward, spirit of our civilization. \ home to distinctive appearance without having t go to extra expense will find in this sign just what he wants. Beauty is gaine through the skillful spacing of the dif ferent parts that make up the walls rathe1 anxious secure than through the addition of decorative features, such as columns, benches, blind and hooded canopies. The construction is of wood with ex The chim ney is common brick, plastered or painted The roof is shingled. A lot at forty-foot frontage is required. terior finish of wide shingles of least