Modern Mechanix, September 1933

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m MILES ON A GALLON Oi GASOLINE WINS ECONOMY CONTEST m MILES Takes %mi Place Winning Cars Equipped With WHIRLWIND CAS SAh A Test On Your Cap sssi mmm FITS ALL CARS WHIRLWIND MFG. COMPANY Dept. 972-A Station C Milwaukee, Wis.

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SEPT., 1933 Donald G. Cooley VOLUME X NUMBER 5 CONTENTS FOR SEPTEMBER SPECIAL FEATURES Mechanical Spot News of the Month - Los Angeles Races Prove Air Thrillers - By James Bowles Jack Dempsey on the Mechanics of Boxing World’s Deadliest Weapons Will Wage Next War . By Russell J. Mort Gas Captures Gangsters Without Bloodshed . Flying With Piccard in the Stratosphere How I Face Death to Tame Jungle Cats - By Clyde Beatty Strange Perils of Making Movies Beneath the Sea . By Homer Scott Mechanical Wonders of Chicago World’s Fair . ? SHORTER FEATURES ke-riding Craze Still Rages Oddities of Science - By Nic Sprank Improve Your Accuracy at Bait Casting - Prize Awards in Gyroscope Fortunes Waiting for Inventors - By R. F. Yates When Mother Earth Blows Off Steam - By Calvin Frazer 1000 Ways to Make a Living New Inventions for Home Convenience Putting Planes Through the Third Degrt By Lieut. Corley McDarment BIG HOW-TO-BUILD ARTICLES Plans for Midget Outboard By Edward Fitzgerald Take Thrilling Underwater Cruise in One-man Sub - Making Your Own Zinc Etchings .... Portable Rig Will Sail Any Rented Rowboat - (Continued on page 6)

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"I ll PROVE in Only 7 Days J. that I Can Make YOUaNewMan! By CHARLES ATLAS No other Physical Instructor in the World has ever DARED make such an Offer 1HAVE proved to thousands that my system of building powerful, big -muscled men begins to show real results in only 7 days— and I can prove it to you. You don’t have to take my word for it. You don’t have to take the word of my hundreds of pupils who have added inches to their chests, biceps, neck, thighs and calves in only a few days. No sir! You can prove for yourself — in just one week — by the change you see and feel in your own body — that you can actually become a husky, healthy NEW MAN — a real “Atlas Champion.” All I want to know is: Where do you want big, powerful muscles? How many pounds of firm flesh do you want distributed over your body to fill you out? Where do you lack vitality, pep, and robust health? Where do yon want to take off flabby, surplus fat? I’H show you that I can make a New Man of you, jjive you bodily power No “Apparatus” Needed ! Let Me Tell You How Gamble a stamp today by mail- ' ;e copy of how I have developed my pupil: to the same perfectly balances proportions of my own physique, by my own secret methods. What my system did for me, and these Send for FREE BOOK 5 Thank You for Me

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Harley- Davidson MOTORCYCLES ! Mail this Coupon— find out how the new manifolding, oiling system, and other features make ‘TNT" the greatest motor we’ve ever ■ " ue “Fighting Heart". i I Name . . . - | Address . . . . i My age is □ 16*19 years, □ 20-30 years, □ 31 I □ under 16 years. Check your age group. .KSSTheaw New "TNT" Motor — Thirty-five Horsepower! Jim Corbett had a "Fighting Heart.” So had John L. Sullivan — and Bob Fitzsimmons. So has Jack Dempsey — and so has this new Harley-Davidson. And what a "Fighting Heart”! Thirty-five Horsepower with a twin- cylinder, 74 cu. in. motor! That’s effi¬ ciency! That’s engineering! .... Just wait till you feel the power — the breath-taking getaway and speed of this "TNT” Motor, now standard in the "74 Twin” for 1934 without extra cost. A demonstration will amaze you. See your near¬ by Harley-Davidson Dealer — look over the 1934 Twins and Singles — ask about his easy-pay plans. Thunk You for Men I

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How Stars Succeed In Love! ^ Learn how the most famous stars suc¬ ceed in love; how they avoid the many pit- falls and malicious in¬ fluences of Hollywood that work to wreck of 2 Great Talkies! You’ll also find a wealth of other absorbing reading including Peggy Hopkins Joyce’s story in want a Hollywood husband. HOLLYWOOD

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TO MEN WHO WANT TO make more money You don’t “get” raises these days— you earn them! These are strenuous times in which we are living. Competition is keen . . . the de¬ mands for efficiency are constantly increasing. The day is gone when you can “hit the boss” for a raise and get it “on your nerve.” You get raises these days on your ability — and your training! Today a man must think about himself — and his future. Remember this : If you’re just getting by, you’re falling behind. Tomorrow your present job may be only a memory. The way to be sure of the future is to be sure of yourself ! Men are realizing this — a new era in the utilization of spare time to acquire special¬ ized training is here ! Men who a few years ago thought they were “sitting on top of the world” today are coming to International Correspondence Schools for additional train¬ ing. Still more are enrolling because they see the handwriting on the wall. They want to make more money. Do you want to make more money? If you do, we challenge you to mark and mail this coupon! It has been the beginning of success for men all over the world. But don’t bother if you’re a quitter! It takes fight and hard work to get ahead these days — and weak-kneed, spineless men have no more chance of helping themselves by spare-time study than they have of getting a raise tomorrow! If you have the old fight, if you’re will¬ ing to risk a three-cent stamp on yourself — mark and mail this coupon today!

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Odd’s bodkins and a straw hat! Up yonder (under the hand so you’ll recognize who we are talking about) is M-M’s pride, the dean of practical American Naval Architects. The designer of such famous ships as Foam, Neptune, Tahiti and others 6tands ashore while a whole fleet of boats passes through a Florida lock! And, dressed in a straw hat, a white shirt, with hands in pocket he goes landlubber on his fans! Gents, it’s John Hanna. Andy’s Shop Mail Box Our owly Greasemonk returns safe as a goose from a long hop to the west, where climate is climate and a growing tree is a miracle. Barge in and get the new slant as Andy digs in. WAL, me b’ys, this rambling rube and hedge hopping haviator is home from a long flug- zeug across der desert to Los Angeles. You’ll notice I spelt it Louse Angles when I said good¬ bye, but after a trip to that fair clime I’m spelling it with respect. Let me tell you — I left Minneapolis about ten days ago and made Omaha the first night. Next day I made Chey¬ enne. Such lovely flat country I never flew over. You coulda come down any where and been on a dance floor. There aren’t any crops to speak of and nothing would have bothered what fiction writers would call the “trucks” of my ship. Salt Lake and south next day. Followed the Union Pacific down the green foothills to the desert, where it was plenty hot even at 4,000 and upwards. And into L. A. that night. Home the same way after visitin’ round a bit. and as the sun was a settin’ I pushed the old Robbinsdale rooster patch down under the nose of the crate in the gloaming, and set the ship in. And just as she settled out from under, I spotted a black wraith smoking like a bullet across the field a la the Pony Express. The Black Thing was Parachute, our little shoat. He literally scooped sand in his hip pockets as he made out of sight in the lone gloaming, which you will claim is leaning some even for a pig. Later in the dark he grunted oi-oi against the hangar door, but I guess he knew I’da up ended 10 him and paddled him for being out alone at night, so he faded. How that pig lives stumps me. And so to work. You’ll be hearing this old sky buster’s comments on the Far West on and off, so lets get into the line of stuff on the spindle. Jack Hanna always makes good copy. Here’s a letter from a Modish Mikkaniks reader down in another hot place. Hearken: Clewiston, Fla. Dear Geesemonkey Andy: Tell me, old pal ole pal, was it the Sage of Dunedin? Was it John G. Hanna? Am I right, or am I a Republican? Dunedin, Fla., dozed in the lap of a sunny summer Sunday morning. Out on the bay a White Leghorn roosterstail cut reckless circles around tactful tackful sailboats. Ahead of the roosterstail zipped a black hull with two arm- waving figures, astern blu-u-r-r-ed a snappy- revving motor. Down at the Dunedin Boat Club a coupla young fella’s rove tackle on a 16-ft. racing sloop. Up at Jones’ Pharmacy brave soda fountain sailors single-handed it around the world. Over in the shallow water around the Dunedin Yacht Club three row¬ boats slowly sunk their gunwales toward lowtide level via seepage. But, hey, what’s that? On past the Yacht Modern M e c h a n i x and

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Club a black hull pulled up on shore glistens through the palms and pines. Going up closer I find it to be a dandy tabloid version of the double-ended Greek sponge-diver’s workboat (the boat is double-ended, not the Greek) like those real salt-in-the-earsers and hair-on-the- chesters operate out of Tarpon Springs. (And don’t try sponge-diving to build up your health, either, for these Greeks break down after not so many years of it, although they are raised in the business.) After taking this advice to heart, come back to the boat. She has a white water line separating the black freeboard from the red underbody, the trim is tan, and the trunk cabin is white. I am all eyes as I come up closer and circle around her. Just as I made a demi-semi-circle, though, of a sudden up pops a duck-legged little squirt in brown tennis shoes, white clothes and grey hair. He shinnies over the side, down past a "WET PAINT” sign stuck between a shoring timber and the hull, and hikes up through a pretty grove of tall pine trees to a white house built with a garage on the ground floor. Duck- legs has the eye of a dreamer, the wrist of a draftsman, the muscle-bound gait of a sailor, and small clearance between his belt-buckle and his backbone. I made him out to be a Naval Architect. Tell me, old pal ole pal, was it the Sage of Dunedin? Was it John G. Hanna? Am I right, or am I a Republican? Yours truly, F. M. Wright. Eff em double you also encloses with his query a posteard like this: Vote here: V Twere John G. Hanna Twerent John G. Hanna V TAHITI will be in next issue? Note: The checks show the way we voted. We publish at the head of this month’s column a picture (first and only one ever published) of the Sage of Dunedin, sent us by a great good guy named O’Connor. This old skeptic unearths herewith for suffer¬ ers from summer heat, a manuscript from J. K. Novins, of Frisco. I’m running it as is in a matter of fact way, for those who plan to skim and skid next winter. It has so much info that I know you’ll gobble it up. The script by Novins, follows: Here is a home-made snow sleigh that runs eighty miles an hour, propelled by an aeroplane motor and operated like a motor car. It is the invention of Harry Edwards, Wallace, Idaho, auto mechanic, and was constructed by him from spare parts. He has run it in town and up steep moun¬ tains where automobiles could not go. It is cap¬ able of slowing down to walking speed, being operated by foot pedal as in an ordinary motor car and is equipped with powerful brakes. A 60 horsepower Anzani Aeroplane motor fur¬ nishes the power. Edwards rebuilt this six cylin¬ der motor with connecting rods of his own design, including the oil pressure and scavenger pumps. The main hulk of the sleigh is built of steel tub¬ ing, with all joints welded. The steering appara¬ tus is like that of a motor car, except that cables replace tie rods to control the runners. The gas tank holding fifteen gallons is in the extreme rear end. The pressure feed and gauges are located under the dash in front of the driver. The aero sleigh weighs 400 pounds and has an overall length of ten feet. It can turn around in twice its length. The sleigh has a seating capacity for two, the seats being upholstered in dark brown. The top, or inclosure, hinges up, to permit entrance. The lower part of the body, including running gear, is painted red, and the upper part is in black, giving the sleigh a nifty appearance. Bill Downey, from the forgotten wilds of Staten Island, New York, sent us an interesting letter about his activities, together with a shot of him¬ self poring over apparati in his lab: 32 Avon Place Tompkinsville, Staten Island, New York. Dear Sir: In the near future I was thinking of con¬ structing a car built after the lines of a racer. "Modern Mechanix” mags ran some designs which were not to my taste, so I am writing to you; perhaps you could help in getting ideas for the construction of such a vehicle. (Continued on page 12) I nv e 11

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ANDY’S SHOP MAIL BOX 12

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ANDY’S SHOP MAIL BOX Don’t let warts spoil YOUR romance BURNING — now unnecessary One out of every three people, accord¬ ing to a famous skin specialist, is afflicted with warts. Common warts appear on the hands. Flat warts oil the back. Often a thread-like growth is noticed on the face, neck, and breasts. Still another form, Verruca Digitata, appears on the scalp. Rather than suffer excisions, caustics, or other old-fashioned methods of wart removal, many people forego the pleasures of those occasions which demand the wearing of bathing suits, or other revealing costumes. And it is all so needless! WART-EX is the clinically tested formula of a famous doctor. Painless. Non-irritating. Easy to apply. Leaves no scars. Put it on at night, and in a few days the results will delight you. Just send 50c with the coupon and mail today. We’ll mail the bottle postpaid and in plain wrapper. WART-EX CO. Suite 600 529 S. 7th St., Minneapolis WART-EX "Ufhsm Ha cm - dvujAa. cjfy" 501] - ](3 Thank You for Mentioning Modem Mechanix uni 1 Russell Manka, of Lamar, Colorado, is a rabid motor- cycle fan, and builds his own angel makers. This is a rolling collection of old parts, soon to ramble. This subject of baby cars, midget autos, racers and track cars, and motorcycles is one which won’t be downed. Witness this letter from the motorcycle and angel -making expert Russ Manka of Colorado: Lamar, Colorado. Dear Andy: Kindly allow me to register a kick on the way the sickle fan is being neglected by M. M. If you will attempt one little think on the sub¬ ject you will realize that it costs less to own a motorcycle than either a plane or a boat. The motor for the plane or the boat will cost as much as the motorcycle. That one fact will be cause enough for more motorcycles than there are planes. In fact, if you have a sickle you may already have the power plant for your plane when, if, and how you are ever able to build it. Some time ago one of your self-appointed critics suggested a Motorcycle and Auto Manual. I heartily second the motion. While I am able to soup up a motorcycle motor till it is putting out the last horsepower I would like very much to have some kind of a refer¬ ence book on the subject. I have been a rabid motorcycle fan since the day of one cylinder, belt drive, pedals for auxiliary power. I am enclosing a picture of a miniature mo¬ torcycle I have under construction with both the reasons why I cannot afford to finish it at once. Wheels are 20x2 off a Culver cycle car, motor is an old Smith motorwheel and the frame is made of bicycle frames and gas- pipe, pinch-hitting for steel tubing. Drive, which has been added since the picture was taken is Vee pulleys and a Model V8 Ford fan belt. Have no provision to date for brakes so may have to carry a chain and anchor. Russell Manka, Box 452. Lamar, Colo.

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ANDY’S SHOP MAIL BOX — a neat effort, Russ. And if any of you gents have a thought on that auto handbook idea, let me hear what you’d think an ideal cargo for such a job would be. This super-shrunk cabin trailer is the work of Mel Thomp¬ son, who flies it behind an Austin. We’ve run pix of all kinds of trailers, and plans for a few. But it remained for Meldrim Thomson, Jr., to send us the midget of them all — a trailer cruiser he built for his Austin. Here she is up above. Neato le babeee pour le auto, or somepin’. Incidentally, “All Sorts” — the 10-foot dinghy is second to “Scram” in popularity. We’ve got a selection of pictures of All Sorts that have been built from Maine to Manchuria. See ’em next issue, boys! While I don’t think the- alleged error is of a nature that could be overlooked by a thorough workman, and while Mr. Dunnan may or may not be right, we thank the gentleman for preserv¬ ing for future use 1,095% readers who might be blown to perdition if the dire things Mr. Dunnan Sidney, Ohio. Dear Sirs: I have been a reader of your interesting mag since 1928 and feel that since I have discovered a -mistake in one of your articles it is my duty to write you about it lest someone be hurt or killed. The article I refer to is the acetylene generator shown in the July Modern Mechanix. You forgot to show a packing gland and nut on the 1*4" auger where it comes through the side at the carbide tank which would let gas escape and cause an explosion endangering the life of the welder. I would advise running a correction in the next mag if you can. The packing box should be packed with a non¬ grease or oil compound such as tinfoil and Hake graphite. I was interested in building the generator for my own use and thus I noticed the omission of the stuffing box. Yours for a good mag, R. H. Dunnan. P. S. I have been welding for several years with tank gas and I thank you for the gener¬ ator sketch for k will save me lots of money by the difference in gas price. — R. H. D. New Canned Wood Makes All Home Repairs Easy Newly discovered wood that comes in cans makes it easy for anyone to keep home in first-class condition. Handles like putty, just as soft. Quickly hardens into wood, like natural wood. You can paint, carve it. Drive nails or screws into it. It’s PLASTIC WOOD. If you have a broken chair . . . loose caster, ugly nick . . . crack in floor, hole in wood, plaster or tile, loose drawer pull . . . rotten spot in wood to replace ... do a quick, ex¬ pert, permanent job of repairing with PLASTIC WOOD. Results will surprise you. Paint, hardware stores sell PLASTIC WOOD for 25d a tube, 35^ a can PLASTIC WOOD ern Mechanix and I Mentions for September When Writing to Advertisers 17

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RADIOLAND Meet all your Radio favorites in this sensa¬ tional New Magazine Read These Fascinating Features in America's First Big Radio Magazine NOW ON SALE at All News¬ stands 15c 18

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Flying With Piccard in Stratosphere ( Continued, from page 5k) to make the metal shell as airtight as is humanly possible. The dowmetal (special magnesium al¬ loy) shell is thoroughly x-ray tested and all the glass ports through which the earth below is viewed are firmly sealed. Inside the cabin, where Piccard and Lieut. Com. Settle, his assistant, must live for 20 hours or more, there are found all the comforts of home, along with a clutter of scientific instru¬ ments. On a small electric stove the scientists can cook meals in the sky. Nearby is a radio transmitter to communicate with the world be¬ low. On another shelf is a strange device de¬ vised by Prof. Compton of the University of Chicago to measure the intensity of the cosmic rays, and next to this is a camera directed down through a special port in the floor. Ranged along the floor is a battery of cylin¬ ders containing liquid oxygen. When an altitude of 15,000 feet is attained the manholes are closed and bolted, and the oxygen valves opened for the rest of the journey to create a livable -artificial atmosphere. This arrangement maintains a pres¬ sure about six-tenths that of the atmosphere at sea level. The climb into the upper air begins about 11:00 o’clock at night for at this time no torrid sun’s rays beat down on the gas bag to cause excessive expansion of the hydrogen. Low buoy¬ ancy thus permits a gradual, controlled ascent. At 15,000 feet, which is attained early in the morning, the fliers close down the manholes. When the sun rises, the ascent begins in earnest. Piccard then begins throwing out ballast — sand¬ bags hung from the gondola and lead dust eject¬ ed through a special valve in the cabin. This procedure continues up through the trop¬ osphere and into the stratosphere, which be¬ gins at six miles above the earth. Meanwhile, overhead the sun’s rays, unimpeded by. the gases of the lower air, along with the diminish¬ ing atmospheric pressure, are swelling the fabric envelope into a gigantic sphere. At about mid-afternoon, the scientists reach their maximum altitude, 11 miles, thanks to the purity of the hydrogen and the lightness of the metal gondola and equipment. Here what is known as the pressure height will be reached; the bag will have reached maximum inflation. Further expansion is relieved by the flow of the gas out of the valve on the bottom of the bag. Descent now begins. The pilot pulls on a cord leading up through the cabin shell to the gas escape valve in the top of the bag. Slowly the stratosphere balloon falls earthward. Down, down, through the stratosphere and into the troposphere. Hydrogen flows freely from the valve, till at last old terra firma comes into view through the haze. Then, just as the gondola is about to strike the ground, the rip cord is pulled, cutting a huge gash in the top of the bal¬ loon and allowing the remainder of the hydro¬ gen to return to the atmosphere. The bag col¬ lapsed, the sky-fliers crawl out of the man¬ hole in the gondola, and another chapter is writ¬ ten in scientific and aeronautical history. •">1 - PATENT Ijaur ideas Small Ideas May Have Large Commercial Possibilities I Serve You in Secrecy CLARENCE A. O BRIEN Registered Patent Attorney WA S H I N G TON , D C. Clarence A. O’Brien, Registered Patent Attorney, 31 77 Adams Building, Washington, D. C. Please send me your free book, “How to Obtain, a Patent,” and your “Record of Invention” form without any cost or obligation on my part. j . (IMPORTANT— Write or print plainly.) j i _ I 19

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CLASSIFIED ADS (Continued from pa9e 21) | SONGWRITERS MAKE MONEY writing songs. Free booklet. Stan Tucker, 1619-B Broad- Bank references. Send 3c postage for 32 page book “Making Inventions Pay." Crescent Tool Company, Dept. T. Cin-

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"j^Dou'ble - Blade Paddle A|llPy'| purfchasedhinh yraftovn— UllCN ' BIG MONEY Assembling NEW BOAT SENSATION Build This GYPSY Trailer for p Vacation Time • 24

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q I— - When Doors Won’t Open Faucets Drip Windows Stick —Fix Them Yourself In these times when pennies count, many home owners put up with the inconven¬ ience of household devices which don’t operate at full efficiency because they hesitate to run up a big bill with the repair man. Wise householders make their own small repairs — and big ones, too — enjoying the full efficiency of their homes and keeping dollars in their pock¬ ets to spend for other things. Any handy man will find it no trick at all to re¬ pair plumbing, plaster, concrete, electric equipment, etc., following the explicit directions in the Handy Man9s Home Manual This book, just off the press, answers just the questions you would ask of an expert if he stood at your side to advise you on your repair job. It is, in fact, the work of many experts, specialists in their fields. The numerous photographs, explicit drawings and clear, easily un¬ derstandable text reduce the problem of household repairs to such simple terms that no man who can handle a hammer and saw need be fearful of his ability. War Fought With Deadlier Weapons (Continued from page 51) flanges as the bullet speeds towards the muzzle. Decided advantages are represented in this ar¬ rangement. The large cross-sectional area of the bullet before firing offers a maximum surface to take the full force of the explosion of the powder, while small cross-sectional area of the “compressed” bullet emerging from the muzzle of the gun reduces wind resistance, and hence loss of velocity, to a minimum. is this combination of features which ac¬ counts for the bullet’s terrific velocity of 5,000 feet a second, nearly double that of standard army rifles, and gives it distinct advantages. The line of flight, or trajectory, is flattened to a minimum so that soldiers need not trouble about adjusting their sights when firing at distant ob¬ jects. Also the time of flight from rifle to target is greatly shortened, a highly important feature for anti-aircraft machine gunners firing at a fast-moving target. Above all, however, whizzing at extreme velocity, the bullet drives straight th hardest tank armor. At such speed, 1 r claims, the projectile has no time to flatten it on striking a hard object; it goes through the steel like a straw goes through a board in a tornado. Military authorities see many tactical advan¬ tages in this new Gerlich bullet and its adoption as a standard instrument of war is expected. The next development to be looked for is an anti-anti-tank bullet armor, and following this, an ultra-high velocity bullet. The next war will also see another new con¬ venience in the art of machine gunning — a phos¬ phorescent bullet which shows the gunner what he’s hitting when he fires into the darkness of the night. Heretofore night shooting has been nothing more than pot-shooting. Except when a parachute flare illuminated the battlefield, the gunners were firing blindly into blackness. Developed recently by the English Chemical Warfare service, the bullet has a phosphorous nose that creates wherever it strikes a luminous splotch, enabling the gunner to get the range of his target, and eliminating all guesswork. CARTO®Nvoo«w»v ’SUCCESS/ ’T COPY - LEARN TO ORIGINATE! 536- Big 3ft. Telescope “SIS 26

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Los Angeles Races Prove Thrillers (Continued from page 36) to Maj. Ernst Udet, German ace who drove to earth 62 allied planes during the World War, and Lt. Tito Falconi, youthful Italian Royal Air Force pilot. European Wizards at Controls These European wizards of the air displayed a prowess few in America have seen. Maj. Udet, particularly, demonstrated the ingenuity Ger¬ many has shown in developing aeronautics de¬ spite the bans of the Versailles peace treaty. He flew his seven-year-old Fokker biplane, pow¬ ered by a 150-horsepower Siemens motor — con¬ sidered by American speed pilots to be some¬ thing akin to a toy — with such skill and daring that a tremendous tribute was paid him. Imagine, for instance, pulling the ship up into a whipstall — straight up until the engine pulls the plane down — only 300 feet above the grand¬ stands; looping the loop with the engine shut off; picking up a handkerchief from the ground with a hook tied to one wing!; barrel-rolling from the ground. Or picture 120-pound Falconi, picked from 400 pilots to represent Italy, roaring down and up in an outside loop, passing within 100 feet of the earth; flying along the ground with his wings vertical, held aloft only by his 400-horse- power engine; climbing straight up hundreds of feet, pulled aloft by his powerful motor. Two pictures of European aviation since the war — the vanquished and victor! Stunting, true: but typical of progress in those countries. Loops Auto -Gyro When the crowds tired of thrilling at these hair-raising episodes, they watched Lt. Johnny Miller loop-the-loop in his auto-gyro. Here was something brand new for National Air Racers, yet the flying windmill looped, whip-stalled and performed wing-overs with the same ease as an airplane. I have seen many parachute stunts, including delayed openings, or free-falls; which means that ( Continued on page 31) Prize Awards in Gyroscope Contest (Continued from page 25) age and its twisting motion would dominate giving the entire device a horizontal, rotary motion. One using this rod might not understand that it would not resist a side thrust, or he might place his weight on one side for too long a period and be twisted from the rope by the horizontal rotation which would result. However, a little practice would enable one to master the eccentricities of the device, after which it would be of value. Yours respectfully, Emmett Healey. We thank all of the hundreds and hundreds of contestants for their interest, and wish to re¬ mind that under the conditions the letters not winning cannot be returned, nor can we enter into correspondence concerning them. MEN WHO WANT TO GET MARRIED! 27

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a Queer Way . to Learn Music / Facing Death to Tame Jungle Cats (Continued from page 60) Having selected my pupil, I must next “barrel- break” him. An animal is not expected to tackle so difficult and elusive an object as a globe with¬ out some preparation. What is chosen for this is a barrel-like cylinder whose surface is covered with a thick matting that enables the animal to dig in with his claws and keep his footing. First the pupil is pedestaled a number of times in succession. Then the pedestal is removed and the cylinder is put in its place. But so that the pupil’s task may not be too difficult, the cylinder is held firm by means of sticks nailed to the floor. The idea is to accustom the animal to one new thing at a time. When the pupil is used to his cylindrical roost, I have the sticks that hold the cylinder firm moved down a foot or so. The cylinder, which is set on a “skid,” or track, starts rolling, and for the first time the animal is faced with the prob¬ lem of balancing himself on a moving object. When his footwork is good enough to enable him to hold on over this short distance, the sticks are so that the cylinder has an additional foot’s play on the skid. Sometimes this is too much for the pupil and he goes toppling to the floor. After about a dozen tries, however, he usually learns to balance him¬ self over this short distance. At the start, the amount of roll to which an animal is subjected is slight. It is controlled by an assistant and me, each of us carrying a T-shaped stick. Because my assistant stands outside the arena, the stick has to be much longer than mine. His job con¬ sists of shoving the cylinder from behind and making it roll. This is the only way we can hope to move a mat-covered barrel on which is perched several hundred pounds of jungle cat. When my assistant finds it difficult to move the cylinder, I assist him from my post inside the arena. Once the animal is able to feel at home on this device, he is ready for a try at a regular globe, although, in the beginning this is also covered with matting as an aid to surer footing. The globe used is a heavy one made of solid wood, two- and-a-half feet in diameter. This, like the cylin¬ der, is placed on a track. At the start the globe is permitted to have no play and the animal is cued to mount it as though it were a regular pedestal. When he has grown used to this new perch, he is put through the rest of the routine that was outlined in connection with the matted cylinder. The wooden bars holding the globe stationary are moved until the big wooden ball has a fair amount of play. When my new globe-roller has learned to balance himself with the sphere in motion over a distance of a few feet, the bars are removed and I set to work on more intricate acts. In most instances, when I step into the arena for the first time with an untied and untried beast, he will halt in his tracks and stare hard at me. His next move is most significant. Either he will conclude that I have no intention of harming him or he will consider me an enemy that he has to fight. If he looks upon me as an enemy, he 28

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Facing Death to Tame Jungle Cats will spring straight at me and try to knock me down. When these early rushes are made by lions, I do not mind them much. Lions are great bluffers and when I stand my ground and meet or side¬ step such a rush, it is seldom repeated. My maned beginners don’t know just how to take me, and when an experimental rush accomplishes noth¬ ing, they calm down. It is the first rush of the tiger that worries me most. When a striped cat comes tearing at me, I use every ruse at my command to defend my¬ self and to make plain to him that I am the boss. To me the arena is familiar ground, while to him it is a strange place; and this gives me a slight advantage, although it doesn’t alter the fact that I have to fight off a determined tiger, which is a very real problem. Most trainers on leaving the safety-cage, to face an animal, shout to the beginner. As I slowly and cautiously leave the safety-cage, I start whist¬ ling. I find this the most effective way of saying “howdy.” The first day, I do not venture very far from the cage, I frankly admit; it is a grand retreat in an emergency. The next day, I go farther into the arena, until, after a few days, I am face to face with my new charge. Oddities of Science (Continued from page 11) Each of the following strange facts about science which upset some of our well established acceptances of things in nature were submitted by M.M. readers to Nic Sprank, and checks for the w.k. dollar were promptly mailed. Probably the most interesting was the one submitted by Dennis Arnold, of Carlisle, up in the State of Washington. Mr. Arnold points out that in the wild animal export trade in Africa the most convenient way to weigh newly-cap¬ tured pachyderms is without scales! The beasts, which would be rampaging if in harness, are usually taken as semi-grown, and will “stand to halter” nicely on the Trading Co.’s barge. The displacement of the barge is then measured, giving a fairly accurate basis for the steamship company to charge for the tonnage. Weight is the basis for all steamship rates. Joseph Mackona, of East Hartford, Connecti¬ cut, among others points out that a dry cell is not dry! He wins over others who submitted the same oddity by pointing out why. The elec¬ trolyte in the battery is really wet, held in suspension by sand, paper pulp and other sub¬ stances in a saturated condition. Lieut. Don Benn Owens, Jr., stationed at Dayton, Ohio, shows that water will start a fire. Potassium and water burn violently when brought together. Jack Bakke, of Wenatchee, Washington, is right when he says that the sun’s rays in them¬ selves contain no heat! The rays set up vibra¬ tions in the objects they strike, and the objects, as a result, become warmed. If the sun’s rays themselves contained the heat, all objects would become warmed equally. [ PLANS FOR I | FINANCING | Become an Expert Accountant The Profession That Pays The demand f< to Audi unceasing. Big Management, Finance! Men who^prove their qualifications earn real salaries. The range is from IKS a year— even to higher income-figures. Send for Free Book — “Accountancy, the Profession that Pays” Why let the other fellow walk away with the better job, when right in your own home you can equip yourself for a splendid future in this profit¬ ary knowledge of bookkeeping is we train you from the ground up, ; ts about the new. LaSalle fully e: countancy and the -ar¬ able field are clearly oul LaSalle will send you fi... The man in earnest to get ahead will find thia coupon a most profitable aid to progress. If you have the urge and the will to increase your income, clip and mail the coupon NOW. - - — Find Yourself Through LaSalle/— - — LaSalle Extension University Dept. 9493-HR Chic: motion in One,” all without obligatic □Higher Accountancy Training for position as Auditor, ~ troller. Certified Public Accou OtherLaSalleOpportuni y important field of Railway Station Mgml □ Personnel Management □ Tele □Credit and Collection C _ _ □ Paper Salesman’s Training imercial Spanish Thank You for . 29

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Send for this new 144 page hook ... "How To Build 20 Boats" JUST OUT! Here's the Book For that fireside or springtime boat fever there is no richer treat than this collection of famous boat designs — some of them hitherto unpublished. All have been test¬ ed in actual use; there are no "duds”. Get your copy of this eagerly sought file of designs, sharpen up that pencil, grip that hammer and satisfy that old urge to build your own boat. for ALL BOAT BUGS!... On Sale EVERYWHERE If your local newsdeal¬ er cannot supply you, send 50c stamps or 50c FAWCETT PUBLICATIONS, Ine. 529 SOUTH 7TH STREET MINNEAPOLIS, MINNESOTA u for Mentioning Modern Mechanix and'Invent ..«*!!- 30 Thank You

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Los Angeles Races Prove Thrillers (Continued, from page 27) the jumper “bails out” and drops a long distance before pulling the rip cord. “Spud” Manning, a jumper of long experience, made even old-timers gasp when they strained their eyes up at the same auto-gyro and saw the tiny jumper leap overboard at an altitude of nearly 15,000 feet. Manning added a touch of stellar showmanship as he fed into the open air wisps of white smoke — really flour — the while he twisted and turned on his earthward plunge. Manning Has a Real Thrill Stunt Down through the sky the floury trail marked his course, though few could see his body as it hurtled downward. After a time the flour was exhausted, the trail disappeared. Then, a mile below the last white puff, the billowing silken canopy snapped open; but not even yet was he safe, for he was suspended beneath a ’chute only 24 feet in diameter. To break his fall further, when a thousand feet above the field, the jump¬ er jerked a second rip cord, and another para¬ chute flew out to slow him down to a safe landing. National Air Races are the crucible in which manufacturers and individuals who think they can build faster airplanes test their products. Here the little fellow gets his chance. Wedell built Turner’s plane and saw Turner outrace him in the two feature events — but he had the satisfaction of knowing he had been defeated by his own handiwork in which an engine of fully 200 more horsepower had been installed. A TRAILER YOU CAN STEER Last word in towing convenience is this trailer chassis which steers just like an automobile. In fact, when towing it all you have to do is steer your automobile and the trailer auto¬ matically follows the car’s motions. No un¬ hooking — no awkward maneuvering in city streets or other crowded quarters. Blueprint Department 01.00. A Real Job Is Waiting for You! You high school graduates who haven’t been able to go to college — You college students who had to drop out after a year or two — You shop and industrial office workers who are stuck in routine jobs — You wouldn’t pass up a Drafting job if you only realized how fascinating Drafting work is — how well it pays — and how quickly you can prepare for a real Drafting job by home study. Will You Look Over- Beginning Drafting Lesson. To see for yourself how fascinating Drafting is, and how easily and quickly you can learn it at home, let us send you (without obligation) a beginning lesson — giving you a week's practice in Drafting work. This tryout will take only a few hours spare time — it may show you the way to success. List of Local Students and Graduates, Will put you in touch with students and graduates, whom you can — " upon or phone. They have been investing spare time in iey-making training. You can profit by their experience. “Selective Employment Service.” Describes how we have helped hundreds of advanced students and graduates cash in on their training by securing good jobs. Instead of filing your application for employment service and waiting for employers to call us. we immediately start an ex¬ haustive search for the right position for you. We welcome this opportunity to show you exactly how >r training will help you by enabling you to try out our aching methods, talk with our stu ' , i our employment service. Before you make ai :h our students, and check up “ “efore you make any de- to yourself to investigate. n for material listed above. Dept. D 623, Drexel Ave. at 58th St., Chicago Address. Thank Yon.for Mentioning Modern . 31

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Mechanical .SPOT Scientific stunts and inventions *1 32 Modem Mechanix and

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AKHS) DM¥iM¥D@KI MINNEAPOLIS, MINNESOTA — PRICE 1 5 CENTS Inventions for September 33

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LOS ANGELES RACES by JAMES BOWLES ROARING across the continent in 11 hours, 30 minutes, Col. Roscoe Turner not only clipped 63 minutes from his for¬ mer east-west trans-continental speed rec¬ ord, but he inaugurated something new in the way of planning his route. The speedy Wedell-Williams low-wing monoplane which Col. Turner piloted has flown in excess of 300 miles an hour, although his average speed across the con¬ tinent was a little less than 250 miles an hour. At that velocity, he cannot afford to fly through rain storms. Avoids Rain by Phoning Accordingly, the night before he took off from New York, he telephoned to Los An¬ geles, where California Institute of Tech¬ nology scientists recently announced a new system of weather forecasting so accurate they can predict where storms will gather anywhere in the United States. At two points along the route, Turner was told,' he would encounter showers. 34 Mode M e chanix and

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T rove <51 IR THRILLERS More and more power and less refinement of streamline design is the cry of present day designers as proved by contesting planes in great 1933 Los Angeles Air Races. Flown across country by an eye witness this up-to-the-minute account of the past year’s aviation progress summarizes records, achievements and points out the races’ thrills. Although he was instructed to turn slightly south from his course be¬ tween two of his stopping points, Col. Turner added the extra miles for safe¬ ty and slid down to a three-point land¬ ing early in the afternoon, a half hour ahead of his nearest competitor, Jimniie Wedell. Increases in Power This year’s races saw more power pouring from the already powerful engines used in the tiny racers. Last year Maj. Jimmie Doolittle won the Thompson 100-mile dash with a 750- horsepower engine pulling his mono¬ plane through the air at Cleveland. This year, Col. Turner won the same epic event with the engine “souped up” to nearly 1,000 horsepower! True, Col. Turner did not reach the speed attained by Doolittle, for fairly heavy cross- winds impeded the racers at Los Angeles. But the increased power indicates the trend in racing. More power instead of more streamlining. The blunt-nosed fuselage has Inventions for September 35

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New Douglas "Gull” Bombers Almost Stall Following Old Keystones 55^ J|j§^ j The Douglas gull^wing army bombers near- } - • IP - ~ - Here's the Douglas 200 mile an hour gull wing bomber that can fly 4,000 lbs. to a height of 20,000 ft. ceiling. It has a hard time slowing down to even the highest speeds attained by the biplane bombers of yesteryear. been accepted as the prevailing style for the larger planes, though some of the smaller ships still make use of water-cooled engines, with consequent frontal area. Despite the cross winds, Col. Turner won the Thompson trophy at an average speed of 241.051 miles an hour, as compared with Doolittle’s 252.686. With the same plane Turner made a dramatic futile effort to establish a new world’s land plane record, but a combina¬ tion of factors, including fog at one end of his course, beat him back to an average speed of 280 miles an hour. The small planes, on the other hand, are getting smaller. Several which had ap¬ peared in former air races were even tinier. S. J. Wittman, of Oshkosh, Wis., flew his tiny ship, “Clipper,” across the continent without altimeter or compass. But note : whereas the wing spread first was 20 feet, he remodeled the plane with a 17- foot wing, while the current model boasts a spread of only 14 ft., 6 in. Every year he “clips” two feet off the wing! These babes of the air come in two elasses, 375 cubic inch piston displacement and 550 inch displacement. They attain speeds up above 200 miles an hour. They land sometimes in excess of 100 miles an hour on wheels hardly larger than your hand. They buzz like bees in the air, yet the pilots “polished” the pylons so closely as they made vertical turns that the casual observer must have thought they’d collapse The Howard, clipped a little from last year, was again favorite and won ^the 375^cu. in. events quite handily. finish lines, “two-eyed” cameras recorded their times and positions — within an accu¬ racy of 1/1000 of a second and a fraction of an inch. These cameras have settled many disputes and have come to be a necessary part of judging finishes. Advent of Low-wing Popularity This year’s races were marked by the al¬ most total absence of biplanes and high- wing monoplanes. All the racers preferred low-wing ships, since they have been found more stable and easier to handle at high speeds. So well did they handle, in fact, that the four days of racing were complet¬ ed without incident, excepting a “stunt” race between two motion picture actors fly¬ ing fairly slow biplanes. “Hoot” Gibson plunged into the earth after a turn around a pylon because his experience was not adequate to permit him to carry the ship through quick maneuvers. He was not seriously hurt. Russell Boardman, who crashed in taking off at Indianapolis during the Bendix dash, died from his injuries. But speaking of thrills — I must pay tribute (Continued on page 27) Modern M e c h a n i x and

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<rRobot Q rashes drains for (fJXLovie thrills HOLLYWOOD stunt men who crash planes, boats, and automobiles to thrill you from the silver screen may soon be replaced by remote control radio appara¬ tus which will put the aforementioned ve¬ hicles through spectacular crashes that no stunter would dare to attempt. The apparatus which relieves stunt men of their perilous tasks is built in two units — one a low-power short-wave transmit¬ ter equipped with an impulse segregator and the other a super-sensitive receiver which picks up the radio signals and oper¬ ates the control mechanism. The operator standing at the keyboard of the transmitter can make a squad of light planes, a pair of automobiles or a squadron of miniature battleships stop, start, back up, turn to right or left.- Severe tests, in which the model train shown in the photo above was employed, indicate that movie goers will witness synthetic thrills startlingly life-like. Inventions for September Oil Can Operates Like Pistol YOU can shoot oil into bearings difficult of access with a new container that operates like a pistol. When your hand wraps around the handle, the fingers nat¬ urally contact the trigger, which, when pulled, causes a stream of oil to shoot from the spout. 37

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prize ring nas ev ier dav, “You can other day, _ the $1,000,000 purse to the boxing world.’ Ring science and mechanics have under¬ gone amazing changes since the Manassa Mauler first started the climb to fame and fortune on the brakebeams of prairie freights nearly two decades ago, culminating in the million-dollar bonanzas which made him the best drawing-card of pugilism. Today the still dynamic Jack Dempsey linds himself transformed from a million- dollar box-office attraction to a million-dollar promoter. He has hung up his gloves, he told me, and is devoting his talents to the emula¬ tion of the great Tex Rickard. “You can’t have million-dollar purses, of course,” Dempsey said to me, “unless you’ve got fighters worth that coin.” He was sitting at his desk in the offices of the Jack Dempsey Sporting Club, 1650 Broadway, New York City, where he is head man as the Manassa Promoter, as his cronies now call him. “ft’s caliber that makes the million-dollar purse,” the ex-warrior continued, “and the pugilist who can command that figure in this depression era has got to have what it takes. He’s got to be the sum total, physically and scientifically, of all the boxers of olden Mod Mechanix and

Page 39

The Manassa Mauler, now turned promoter, here tells Ben Lincoln some of the es¬ sential mechanics to he close¬ ly watched in the develop¬ ment of a real champion, adding illustrative excerpts from his colorful experiences. days, of the gold standard age. “First and foremost, he’s got to be a fighter. A real, fero¬ cious fighter at heart. The so- called fussin’-around type does not go. They used to call me the Tiger, well, that’s what he’s got to be like. Action, that’s what the customers crave. I gave them all the action I was capable of, down to the last gasping breath. It was that courage and the desire to give everything I had that made me the recipient of the first mil- lion-dollar purse ever paid to a boxer, the highest price ever paid for any sport¬ ing exhibition. “Another thing, the million-dol- lar fighter has got to be able to take it, stand¬ ing up. Nothing gets the crowds op their feet quicker than when a game battler refuses to give up, and go down, but pluckily keeps fighting back and boring in with both fists when his adversary is actually battering him down. I know of no thrill like that which conies from springing into the lead from what a moment before looked like hope¬ less defeat. “The big-time and big- e mb e r Invent i s for Se pt< 39

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Most Effective Blows in Dempsey Repertoire Explained Step by Step money fighter has got to have a sort of dramatic make-up. That’s the best way I can explain it. People in show business call it personality. You don’t exactly cul¬ tivate this. You’re born to it. It’s what they call inherent. This dramatic trait is what comes to the surface on the spur of the moment, instinctively. There’s something heroic about it. It wins the hearts of the multitudes. “For instance, the most dramatic mo¬ ments I have ever experienced in the ring Occurred on the evening of Sept. 14, 1923, at the Polo Grounds, New York City, in my bout with Luis Firpo, whose monicker was the Wild Bull of the Pampas, because of his Argentine origin. “I knew very little about the Argentinian. One thing was apparent, he was a very huge and powerful fellow. I couldn’t help grin just a little as he stepped from his corner at the crack of the gong, holding his right hand poised aloft, in the manner of ‘tele¬ graphing’ its movements. “Hardly had we warmed up with a few casual taps than the challenger brought down that right hand with a smashing trip¬ hammer blow. The sock jarred me. I was momentarily stunned, and quickly realized that this was no ordinary hombre. “I’m sure no one knew I was startled by that first blow. I managed to retreat gently, and did a little bobbing and weaving, and then I sprang up swiftly, clipping him on the chin with a short left hook that carried plenty of business machinery with it. Down he went. “He was up in three seconds and, acting instinctively, I let him have anothei ?ft hook. I must have figured he was weak on that score and that since it worked once it was worth a second try. Firpo dropped THE PISTON PRINCIPLE IN BOXING 'Don’t telegraph your Irtist’s sketch shows why a j THE LEFT/ HOOK I and

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Secret of Jarring Punches Lies in Throwing Weight of Body Properly » second time. He was up, and the same punch sent him down. I don’t know myself to this day how many times he was up and down, but I still can remember the sensa¬ tions which shot through me when he rose and rushed at me. “In those very brief moments he loomed far more infuriated and raging than any of the wild bulls of his native clime ever appeared. He made one last lunge at me, swinging his clumsy left, and I was half- knocked and half-pushed through the ropes, landing on the press-stand skirting the outside of the ring. “I was pushed back into the ring by those nearby into whose midst I went sprawling. I remember the scene was one of wild pan¬ demonium. I can still hear the deafening echoes, the cheers and yells of over 140,000 spectators. “As I was about to strike up a lighting pose, Firpo was again on top of me, bent, no doubt, on polishing me off. But my tim¬ ing was good. I caught him with another hook and he slipped to the mat. The gong clanged and the most spectacular round I ever fought was over. I might say that I am reasonably sure that it was the most startling three minutes that any fighter ever experienced. “In 58 seconds of the second round I knocked out Firpo with the tell-tale left hook, thus ending the most dramatic episode in my long career as a heavy¬ weight boxer. The gate for that fight was well over §1,000,000. My share was §470,000, or about $120,000 per fighting minute, a rate of compensation unknown to any other sport, or I might add, to any other scrapper. First Million Dollar Gate “Tex Rickard as the nonpareil showman in the annals of sport was the creator of the million-dollar gate, so to speak. It was originated at Boyle’s Thirty Acres in Jersey City where I fought Georges Carpentier, champion of Europe, on July 2, 1921. That fight drew $1,600,000 and it was the be¬ ginning of the Golden Age of sport.” On Sept. 23, 1926, when Dempsey lost the title to Gene Tunney at the Sesquicentennial in Philadelphia, over 120,000 persons paid $1,895,000 in admissions. A year later prizefighting reached its golden peak in Chicago when the customers paid — again under the auspices of Tex Rickard — $2,- 658,000 to see Gene Tunney retain the title under Dempsey’s onslaught, and also get the famous Chicago long' count. Almost simultaneous with the Wall Street debacle of 1929, boxing also hit a decided bearish trend. For almost four years there¬ after the fight game seemed to be a lost pro¬ fession and the big purse seemed doomed. Jack Dempsey, came along last spring and revived hopes by proclaiming that he was lave Sep b e r 41

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Jack Dempsey Lists Vulnerable Points of Attack in Scoring a Knockout HE "BUTTON" SOLAR PLEXUS- going to become a fight promoter and that his object was the return of the million- dollar gate and purse. His first official act was to sign up Max Schmeling and Max Baer for an appearance in June at the Yankee Stadium in New York. At the time he was optimistic, fore¬ casting that the bout would bring back the million-dollar gate. He predicted that the $1,000,000 purse would return this fall if he was successful in matching the winner of the Schmeling-Baer fight with Jack Shar¬ key, the heavyweight titleholder. Thus we find the last cycle in the evolu¬ tion of Jack Dempsey, the big business man of sportdom. He came from humble begin¬ nings, without the luxuries and advantages which fall to lads with well-to-do parents. His father was a rover of Irish descent and his mother was Scotch-Irish. When he was in his early teens his impoverished family moved from West Virginia to Colorado 42 where young Jack divided his time by working on a farm and in a mine. “I got exactly sixteen bucks for my first fight,” Jack told me, “and my second start brought me $25. Finally I got into the $500 class, and I certainly had to bowl over some mighty tough palookas to collect my cash. But it was all a great training-school for the future. I got on to the rudiments of the business early and it wasn’t long before I knew I had a smart left hand, consisting of a triple-threat-jab, hook and uppercut. “There’s more to the boxing game than sheer, brute strength. It’s the knowledge of how to use those primary elements which counts. You can take a man with a power¬ ful right hand, but if he does not know the essentials of boxing science and me¬ chanics, he’s a hopeless dope when pitted against a much weaker antagonist who has mastered efficiency and effectiveness in ( Continued on page 137) Modern M e chani x and

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Bike Riding on Tight Wire RIDING her bicycle along the popular beach at Venice, California, near Holly¬ wood was too tame a pastime for Billie Yuill, so with Isabelle Becker to help her maintain her balance she tried out the stunt illustrated. Taking the tires off the wheels of her bike and with Isabelle in a rope swing underneath her “bike,” she rode the life¬ line along the beach. What Weather Most Comfortable? A TABLE of the kinds of summer and win¬ ter weather in which average Ameri¬ cans should feel comfortable has been pre¬ sented to the Franklin Institute, in Phila¬ delphia. In winter, average people should feel comfortable at any temperature be¬ tween 63 degrees and 71 degrees and when the relative humidity of the air is between 30 per cent and 70 per cent. In summer, the accepted comfort zone moves to higher temperatures, including any temperature between 66 degrees and 75 degrees. The comfortable range of rela¬ tive humidity in summer remains the same as in winter, between 30 and 70 per cent. "Pressing” a Lot Into a Little Space BOVE is seen a project that should be dear to the heart of a dyed-in-the-wool model maker. It took some real designing, to say nothing of the most painstaking con¬ struction to “press” this real flat-bed Webb printing press into such small dimensions. This press, which is said to be the smallest of its kind in the world, contains every fea¬ ture and device of the regular size presses of which it is a counter-part, and is an out¬ standingly interesting exhibit of the “Cen¬ tury of Progress” Exposition at Chicago. Miss Irene Donnelly is shown about to start the press on its production run. Inventions for September Is Latest in Hollywood Fads Q , This, as might seem at first glance, is not a new form of life saving conveyance, but a new beach sport in Venice, Cal. New Trunk Wheels on Turntable LAST word in convenience is represented in a new trunk which does not need a couple piano movers to juggle it into posi¬ tion! The new design is fitted with a turn¬ table bottom. A light push will whirl it around so that any of its compartments can be easily and quickly reached. Five metal feet on the disc or turntable elevate the trunk slightly off the floor and prevent the stationary part of the bottom from touching floor when trunk To save wear and tear on disposition of user, this trunk is conveniently mounted on a turntable for accessibility. 43

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<rRaging~rRentals Make Money CREDITED to comely Miss Joan Crawford who started daily bike riding six years ago as a method of keeping physically fit, the bike riding fad has swept to all corners of the nation. Bicycle makers rub their hands with gusto, wink at the Depression, and continue to sell great quantities of wheels at around twenty dollars per ma¬ chine. No little part of the present craze is due to the improvement in bicycles, which now ride smoothly, have cut-away frames and chain guards for skirts. Balloon tires, brakes on both wheels, su¬ per comfortable seats and silent chains are improvements which the present day bicycle rider demands. A large part of the faddists are women and it has been said by a number of prominent physicians that the riding of a bicycle develops shapely legs and reduces a flabby torso in a way no other form of exercise can do. Which pos¬ sibly accounts for the popularity of the sport among women. Many concessionnaires, always alert to profit, are setting up stands where bicycles may be rented. From Los Angeles to Boston in all major cities wheels can be rented at 25c per hour, and many operators have rented a dozen bikes in such a way that their original investment has been returned in a week. Far from dying out quickly as did the Miniature Golf Course idea, bike riding is taking hold more and more strong¬ ly; one devotee tells another, makes up a party, and it’s a poor location that Can’t make money with a bike stand these days. c h ani x and

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ST. PAUL, Minnesota, boasts a new night club said to be without equal anywhere in the world for novelty and comfort dur¬ ing torrid summer months. Called the “Mystic Caverns,” the club occupies a laby¬ rinth of caves which form a natural refri¬ gerator with a year round temperature of 48 degrees. The subterranean chambers where the revelers disport themselves have their opening in the face of a towering sandstone cliff bordering the Mississippi. Once you step inside you are literally in the bowels of the earth, with solid sandstone walls all around you and 150 feet of solid sandrock overhead. About eight degrees of heat make the at¬ mosphere decidedly comfortable inside the caverns when the mercury is flirting with the hundred mark outdoors. In winter, 20 degrees of furnace heat convert the labyrin¬ thine chambers into a cozy beer hall. Oiling Saws Kept in Damp Places TO preserve you saw against rus slip it through i slot cut in a 1x2 linedwith an oiled fabric, as shown in the photo. A few slides after us¬ ing will keep the metal well greased. The 1x2 can be mounted conven¬ iently overhead. Canvas will suffice for cloth. Inventions for September 45

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New Device Feeds Golf Balls to Tee for Practice Driving A PORTABLE, automatic ball teeing de¬ vice now available for golfing addicts, feeds the balls, one at a time, front a spiral magazine to a rubber tee, from which the player drives it. By the time the player has watched the first ball to its landing place the machine has accurately placed a second ball on the tee. The machine shown in the picture holds fifty balls but any number less will operate as well, and an extension to the magazine of the machine would permit any additional number. The mechanism of the device con¬ sists of a magazine trigger lever and a feed lever and weight delivery trough — all con¬ trolled by the weight of each successive golf ball as shot or driven and without the use of springs or gears. Vest Pocket Auto — Almost! HERE is illustrated Vince Barnett seated at the wheel of his diminutive Muller Special, a single cylinder automobile that can be driven through Hollywood on one quart of gasoline. Barnett must be having some “heavy” mechanical trouble as he sits “in the driver’s seat” while being “held-up” on one of his trips — with his car being jacked up in preparation for a tow in to the nearest garage. Greatest Mountains Never Seen THE world’s greatest mountain range is one of which no man has seen anything except a few of its topmost peaks. Almost the whole enormous mountain chain is under water. It is what oceanographers call the Mid-Atlantic Rise, about halfway between South America and Africa and stretching northward to Iceland and south¬ ward to the Antarctic continent. The Azores islands are a few peaks of this range tall enough to reach out through the water. Fore! and up to 50 at One Stance LAKE Merritt, Oakland, California, Break¬ fast Club members are practising for their first “Aquatic Golf” tournament to be held on the lake. Six teams will be entered in the contest, each team consisting of one golfer who will “tee off” from a specially constructed raft, and a boat manned by four oarsmen to act as “Greens Committee” and caddies. Regu¬ lation golf clubs and balls will be used but bathing suits will be worn! W. A. Davis, club president, is shown ready to try a shot from a raft out into the lake, while Madelon Sivyer, club mascot, looks on. 46

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Ultra-Violet ‘Rays Shift Picture .SCENES ON DISPLAY at the Chicago Century of Progress Fair is a painting which mys¬ teriously changes its scenery in the space of an eye-blink. That is, it’s mysterious until you learn that ultra-violet rays are being played on the canvas. A new kind of color¬ ing substance makes it possible to have two paintings in one. Invisible under ordinary light, these Strobilite colors, as the pig¬ ments are called, may be applied to any painting without changing its appearance. In darkness, however, when subjected to ultra-violet rays, the scene changes because only the Strobilite colors then become visi¬ ble— a result of their peculiar quality of fluorescence under these conditions. Under ordinary lighting the painting shows a picture of children at play beside a lake, but when the lights are turned out and the painting is subjected to ultra-violet rays, the children are shown in a play room under a sun lamp. Handiest Grinder for Workshop EXTREMELY handy for small grinding jobs in the workshop is a diminutive grinder which proves ideal for getting into tight, awkward places. The motor is contained within the handle, as may be seen in the drawing at left. The grinding wheel provided is conical in shape and proves the most adaptable for general work. Other shapes are available for other types of work, however. Careful balancing permits . . . . . . the most delicate Midget grinder has motor in , handle. Ideal lor small work. WOrk. Cheap Radio From the Power Line rpHERE is a promise of a serious threat A to the radio industry represented in a new type radio receiver which, the inven¬ tor claims, will eliminate ordinary broad¬ cast receivers altogether. “Futophone” is the name of the instru¬ ment, and it is claimed that with it anyone can tune in any local or long distance broadcast by simply plugging into the elec¬ tric light line. The heart of the device is a special microphone taking its juice and signals from the power line. Programs from any Inventions for September 47

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World’s ‘Deadliest ‘Weapons While peace parleys convene, only to end in failure and increased hatreds, military inventors smile to themselves and go on perfecting their engines of death. This article sets forth ad¬ vanced data on these new weapons and tells how they will add deadliness to combat when they appear at the Front in next war. by RUSSELL J. MORT FROM the bow of a submarine lurking submerged in the offing shoots a tor¬ pedo bound on a mission of destruction. Leaving a streaked wake as it cleaves the water, it speeds straight for the hull of an unwary destroyer cruising across the horizon. In the crow’s nest of the destroyer, the lookout scanning the sea’s surface for any sign of an enemy, picks up the white foam¬ ing line whose point is tearing towards his vessel. Without a moment’s hesitation he shouts the ominous warning into the speaking tube leading to the bridge: “Tor¬ pedo off the starboard beam!” Hard A’port to Avoid Torpedo With cool haste the destroyer’s com¬ mander signals the helmsman to put the wheel hard a’port. Then while the long, deadly torpedo dashes ahead, the lean, gray destroyer swings sharply to the left, and the commander breathes a sigh of re¬ lief, for he believes he has maneuvered around in time to get out of the path of the onrushing missile. But suddenly and unaccountably the tor¬ pedo alters its course, too, and makes a bee-line straight for the destroyer’s hull. The ship’s commander is bewildered at these strange antics. Again he signals hard a’port. The vessel swings around again, and again the torpedo, now only a nun- dred yards off, changes its course — straight toward the war dog’s hull. No Escape The commander shouts orders for the third swing to port, but it’s too late. The torpedo dashes against the destroyer’s side and there is an ear-splitting detona¬ tion. Like some inescapable undersea Nemesis, the submarine’s missile has hunt¬ ed down its victim and sent it to the bot¬ tom of the sea. Thus may naval encounters of the fu- Modern Mechanix and

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eMU “WAGE NEXT “WAR ture result, thanks to the development of a new type of torpedo which will literally chase its victim around the ocean till it finds its mark. Complete details of the amazing torpedo are veiled in secrecy. However, sufficient information has been released by its in¬ ventors to give a fairly clear idea as to the operation of its mechanical steering brain. Infra-red Rays Steer Torpedo The secret of the steering mechanism lies in the electric eye built into the nose, just beside the detonating cap, as illustrat¬ ed in an accompanying drawing. Special filters mounted in front of the “eye” screen out all but infra-red rays, that is, the invisible heat rays at the lower end of the light spectrum. When infra-red rays impinge upon the electric eye, a current passes through it which operates a set of relays controlling the steering mechanism of the torpedo, shifting the rudder to direct the missile in the direction from which the infra-red rays ema¬ nate. Now most all bodies which radiate heat radi¬ ate infra-red rays, heat and infra-red rays being practically the same thing. A naval vessel ra¬ diates a slight degree of heat from its engines and it is these infra-red rays which attract the torpedo to the vessel’s hull, much as a magnet attracts a piece of steel. No matter what maneuvers the ship may go through, the torpedo, speeding towards the source of the infra-red rays, will always strike its target. One of a number of new instruments of war, the invention of this new engine of death points out a distinct trend in the de¬ velopment of weapons for future wars. There is much wild talk among laymen in military matters about weapons so hideous that in battles in the next war whole regi¬ ments will be annihilated in the batting of an eye. Thorough research on the part of Mod¬ ern Mechanix and Inventions correspon¬ dents, however, indicates that military in- Septembe 49

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Mile-a-Second Compressible Bullet Pierces Hardest Steel Tank Armor Modem Me chani and

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Radium-nosed Bullet Shows Night Machine Gunner What He’s Hitting An invention of H. Gerlich, a German ballistics expert, the bullet is now under investigation by small-arms technicians of the American Army. The secret of the extraordinary armor- piercing power of the new bullet lies in its “compressibility.” The projectile goes in at the breech at .35 caliber and comes out the nozzle .25 caliber. This compres¬ sion is effected by tapering the bore as illustrated in an accompanying drawing. The projectile is equipped with two flanges, .35 caliber in diameter which slip into the ammunition chamber of the rifle, whose bore is channeled to fold down the ( Continued on page 26) Tube Plants Seeds One at a Time THE difficult job of handling small seeds while planting them is made easy with a pointed glass tube through which the seeds are shaken into the ground. The en¬ tire packet of seeds is emptied into the tube. They will not run out freely, a slight shake being necessary to make the u out in uie sou me ■isl given a quick ntir diffe available for^various types Ornamental Table-top Greenhouse FIRST prize for the last word in unique¬ ness in the way of home ornaments goes t© a table-top greenhouse built by a Boston workshop fan. Shown below, the house measures one by two feet and contains a stand of small evergreen trees, along with other small decorative plants. A rock gar- “65 i 'anPd0water°le^eln/n1the<pool.t ' Inventions lor September 51

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Qas Captures Qangsters Without Bloodshed Paris police are shown hauling out gangster overcome by gas. GAS bids fair to replace bullets in bring¬ ing criminals to justice. Experiments conducted recently by the French Gas Brigade proved that an injec¬ tion of gas into an underworld hideout renders the victims helpless in short order and, more important, avoids loss of life. The procedure of capture is illustrated above. Policemen bent on compelling a sur¬ render approach the door of the hideout behind a bullet proof shield, meanwhile calling upon the felons to come out. Upon refusal the besiegers bore a hole in the door, slipping the bit through an opening in the shield, insert the pipe from a tank of asphyxiating gas, and open the valve. Shortly a series of gasps are heard followed by the thuds of falling bodies. All that is left then for the police is to haul the unconscious bodies off to jail. 52 M e c h an i x and Mode.

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Electrically Heated Grandstand for Winter Football Games AN INTERESTING experiment is being made in England in the grandstand of the Manchester United Football Club. A sec¬ tion of the stand containing about fifty seats is given over to four 2 % K. W. high temperature radiant electric heaters placed about ten feet above the heads of the seated spectators. The field of heat from these units radiates over this entire section, which is thus flood-heated. It is said that the com¬ fort of the spectators has been considerably enhanced. The first cost of the installation is high but the operating cost is low because heat is required for but short periods. Portable Power Plant for Odd Jobs ANEW portable generator, almost small enough to put in your pocket, weighs only 35 pounds, stands about one foot high, yet is capable of generating enough elec¬ tricity to run a % H. P. motor or to light ten 40-watt bulbs. A small one-cylinder air¬ cooled gasoline engine runs the generator, and both of these are combined into a single unit with the gasoline tank logically con¬ fined within the base. No technical training or experience is required to operate it; it is quickly started by giving a sharp jerk on a cord wound around the end of the exposed flywheel. Then the tool or appliance to be run is simply plugged in. It will run for three to five hours on one gallon of gasoline; oil is mixed with the gaso¬ line and automatical¬ ly lubricates all parts through grooves in a hollow crankshaft. This portable gen¬ erator can be used at camp or summer home and will oper¬ ate all kinds of tools or even aviation searchlights. An extremely con¬ venient use to which it can be put is seen in the photo. Suffi¬ cient juice is deliv¬ ered to operate any electrical workshop tool. Portable generator operates electric tools and electric house¬ hold appliances where commercial power lines are lacking. Inventions for "Heavy Duty” Pencil Sharpener THERE is probably no device, in shop or office, that gets more use and abuse and yet less attention than the well-known pen¬ cil sharpener. It is used by everybody and cleaned out by nobody! It is very easy for one machine to be¬ come so clogged up that it is impos¬ sible to sharpen a pencil without breaking it. Here is a solution ar¬ rived at by taking a biscuit tin and mounting it di¬ rectly under the sharpener instead of the little con¬ tainer furnished. Such a box will go for several weeks without need of emptying. It is a practical arrange¬ ment where there pen(:il sharpening set-u are many users. shown seldom needs emp Sept

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FLYING with TICCARD Behind the newspaper headlines relating the progress of Prof. Piccard’s stratosphere flight lies this fascinating story of the scientific details of the amazing aeronautical adventure. WHEN the Piccards take to the stratos¬ phere in search of new data on the be¬ havior of the mysterious cosmic rays ema¬ nating from interstellar space, the pulse of the whole civilized world beats a little fast¬ er. The imaginations of millions of peo¬ ple are aroused to new heights by the thought of a pair of scientific adventurers penetrating the icy reaches of outer space, there to wrest from the universe a few more of its stubborn secrets. To the awe-stricken public following in the newspapers the trail of the stratosphere navigators, the flight is an amazing adven¬ ture into the heavens. Behind the scenes, however, lies another adventure which will elicit the keenest interest for Modern Me- chanix and Inventions readers. The extensive preparations made for the flight, the intricate calculations involved in floating the great gas bag up into space, the unusual construction of the stratosphere gondola, and the way the intrepid space navigators live during their journey through the void — all these details make a fascinating story within a story. Filling the huge balloon in preparation for the ascent is a spectacle. Into an appen¬ dix-like arrangement at the bottom of the bag — a small tube several feet in diameter — is fed 125,000 cubic feet of hydrogen 99 Vi per cent pure. At first lying flat on the ground like an unhoisted circus tent, the giant envelope begins to rise in the middle like a bubble, then, as gas is fed in, it assumes the shape of a fantastic mushroom growing at a startling rate in the cool of the evening of the ascension. When completely inflated for the take¬ off, balloon is an elongated, flabby, billow¬ ing bag only 25 per cent filled with hydro¬ gen. This strange sight, which makes un¬ scientific onlookers wonder how such a thing could ever get off the ground, is due to the necessity for expansion as the balloon rises into the rarified atmosphere, where, at 11 miles altitude, it attains complete dis¬ tension. While the ground crew hangs onto the array of ropes depending frOm the enve¬ lope, the stratosphere fliers climb into the cabin through the two manholes on the sides. The globe-shaped cabin is seven feet in diameter and rests in a ring-shaped cradle. In deference to scientific laws, the top of the cabin is painted white, the bottom black. At extreme altitudes the gondola’s white top will reflect the intense rays of the sun, and thus avoid overheating of the occupants. The black portion absorbs suffi¬ cient heat from the earth to keep the fliers comfortably warm when the temperatures are dropping to 75 below zero. Leakage of air from the sealed gondola at 10 or 11 miles above the earth would be fatal to the scientists, so care has been taken (Continued on page 19) 54 Mech

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in the .STRATOSPHERE

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^ow <] tyaee ‘Death mm Death lurks in every motion of the jungle cats going through their paces at the circus under the unflinching eyes of Clyde Beatty, famous animal trainer. In this fascinating behind-the- scenes view, the author of "The Big Cage”* tells how mechanical tricks aid in quelling violent lion-tiger battles and in developing sav¬ age jungle beasts into brilliant actors. CIRCUS-GO] watching me p their paces in the big cage, a I who sit breathlessly it my jungle cats through big cage, and expecting a howling bedlam to break loose at any mo¬ ment, are seldom aware that their expecta¬ tions are much closer to realization than they would like to believe! Behind the seemingly orderly procedure of my animal acts in the big cage there seethes the pent-up fury of vicious jungle beasts who not only hate their human mas- v performers, and 1 themselves, imal vengeance al¬ ways impends, and when it breaks all the resources of human will power and scien¬ tific ingenuity are required to bring peace and quiet again. An experience that comes close to being the greatest thrill of my life took place when we were playing at Collinsville, Pennsyl¬ vania. This dramatic happening has since become known around our show as the Battle of Collinsville. My animals had behaved well for five con¬ secutive performances, and I was antici¬ pating no trouble — that is, nothing out of the ordinary — when we reached this Penn¬ sylvania town. All went well during the Modern Mechanix and 56

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as s:".s performance saw my act pretty nearly wrecked. It was then my regular practice, in get¬ ting things under way, to start by letting three tigers into the arena. They were trained to take the three high pedestals. Then I sent the lions in — twenty males and females — holding back the rest of the tigers until their enemies were seated. My lions always mill around on the floor until I make my entrance. There is a throng of lions about the safety-cage where I stand, armed with chair, gun and whip, ready to fight my way into the arena. As I stood peering out of the safety-cage that day in Collinsville, one of the lions leaped high up without warning and dragged Rosie, “the roll-over tiger,” down from her lofty seat. As Rosie landed on the floor, lions started after her, but she fought herself free before any one of them could secure a real hold, and scrambled back to her perch. She was just getting seated as I made my entrance. Cracking my whip and blazing away with my gun, I quickly got the lions up on their pedestals. Then I let in the rest of the tigers and seated them. ranged around the arena, I have formed the living pyramid that features the first part of my act. I had hardly pyramided the group when Snip, a tigress, jumped off her pedestal and ran under the pedestal occupied by a scrap¬ py lioness. Infuriated, the she-lion jumped down qn top of “Snip.” Then, almost in¬ stantly, Duke, the big lion that had started the fight with Rosie a few minutes earlier, jumped down off his pedestal and grabbed a tiger. All the other tigers except three jumped to the floor of the arena — not so much to join the fight as to be in readiness to leave the arena. There are no greater scrappers than tigers, but they avoid fights, whereas the lion instinctively starts a fight. The tigers had hardly touched the floor of the arena when the lions, every single one in the act, were after them. Each lion was making a lunge for the nearest tiger. The arena was now in an uproar. It fairly quaked with the struggles of the com¬ batants. All of my animals except three tigers — Rajah, Empress and Rosie — joined the awful free-for-all. This meant that twenty lions were fighting nine tigers; and Inventions for September 57

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Tiger Is Best Scrapper But Avoids Fight When Possible; Lion Attacks unless I could quell the riot that in its opening moments breathed more hate and murderous intent than any animal fight I had even seen, it was a reasonable certain¬ ty that some of my tigers would be wiped out. There was only one thing for me to do and that was to get out of the arena if pos¬ sible and from the outside try to drive some of the combatants through the tunnel and back into their cages. The tunnel door was wide open. So great was the din of the battle that the boy at the door was unable to hear my cry : “Let ’em out. Let ’em out!” But my frantic gestures had made clear my meaning. Nothing, however, was accomplished. The tigers would have been glad to leave the arena, but there were too many lions on top of them. All around me I could hear the shrieks of horrified spectators. I was a bit dazed from the shock, but my head cleared and I set to work doing what I could to break up the fight. Assistants had been standing ready to pour ammonia into the arena, but they feared that in addition to affecting the ani¬ mals the fumes might overcome me. I sig- £ior» and tiger locked^ in mortal ^combat. The^ tiger ^s^a nailed them to let fly. At once several of the struggling beasts, coughing and chok¬ ing, dashed for the tunnel door. Only nine animals now remained in the arena — seven lions and two tigers, one of the latter ob¬ viously dead. Yet the lions continued to maul the lifeless body. I decided to go in and break up the rem¬ nant of the fray. One of the animals lunged for me as I neared the group, but I turned him with a blaze from my blank-cartridge gun. Then, alternately using my chair, a pole, and a gun, I drove the last of the war¬ riors from the arena — all except the two tigers. One was dead and the other, Snip, 58 Modern M e c hanix and

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Animals Are First Taught to Mount Blocks, Then Higher Pedestals was badly injured. Poor Snip died three hours later. The Battle of Collinsville made a lasting impression on me. For weeks, in my sleep, I could see that pack of lions and tigers to¬ gether in deadly combat. The experience came as close to unnerving me as any I’ve ever had — perhaps a little closer. However, no matter how much trouble my charges may give me, I never bear them any grudge. Long years of intimacy with them have taught me their habits and limi¬ tations, and I And we get along much better when I try to understand them rather than beat them into sullen submission. That’s the reason, no doubt, why I know them so well. Four animals out of five can be taught to perform if they are started early enough — that is, when they are between two and two-and-a-half years old. When I say, how¬ ever, that most animals can be trained if they are started early enough, I do not mean to imply that most of them can be de¬ veloped into expert performers. Only a select minority possess that indefinable spark and ready responsiveness that a trainer quickly recognizes as arena genius. When an animal is unusually tough or the time for breaking him in is limited, his first appearances in the training-den are controlled from the outside. A leather col¬ lar, about two and one-half inches wide, is fastened around his neck. When the begin¬ ner is a lion or a tiger, the leather used is heavy and every inch of the collar is re¬ inforced. Breaking in Mean "Cats” A heavy steel ring, with plenty of play, is slipped over the collar before the latter is attached. To this ring a chain about two feet long is fastened and to the chain a heavy rope is tied. The big cats are very expert at the business of chewing a rope in two, no matter how heavy, and the chain serves to keep the rope out of their reach. The rope is slipped through a heavy iron ring on the arena floor and then through the arena bars, where it is held taut by at¬ tendants who pull the pupil away from the teacher when the pupil attacks too vi¬ ciously. My first job after my pupil has become used to his new surroundings is to get him to practice cage entrances. I “break” him to go to the right or the left when he leaves the tunnel and enters the arena. Which¬ ever side I dictate, that’s his side of the arena during the early stages of his career. Once I make an animal understand clear¬ ly whether he is to go to the right or left on entering the arena, I devote myself to “seat-breaking” him. The first seat used is what is known in the animal-training world as a “block-seat.” This is a solid block of wood that simplifies matters considerably. Snarling and resentful, a jungle eat dropping to his haunches as the first step in the famous . roll-over stunt, ntrol — -obviously he cannot pick up tiger and roll him over like tame animal. Inventions for September 59

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Trainer Holds " King of Jungle” at Bay With Legs of Ordinary Chair The average lion or tiger, motioned toward such a seat, understands that you want him to get up on it. The next move is to cue him to clamber up, which is not difficult to do except when you are dealing with a suspicious animal. Irrespective of how much of a doubting Thomas an animal may naturally be, once his trainer gets him on a block seat and he sees that nothing is happening to him, he is sold. While I always start the “seat-breaking” of an animal by teaching him to get up on a block seat, I also have regular pedestals, of different heights, in the arena. After a pupil has been block-seated, it is fairly easy to make him try the other pedestals. When he finds he can go scampering from seat to 60 seat until he reaches the highest perch in the arena without anything happening to him, he begins to develop confidence in his new surroundings. Within a month, I usually have a rookie animal taking any one of six seats in the arena. I keep him hopping from pedestal to pedestal at my command. Then one by one, five of the seats are removed and the pupil soon understands that the one remain¬ ing is his own special perch in the ring. Globe-rolling is a real step forward In the career of a big cat — lion, tiger or leopard— that is studying to be a performer. When I start an animal on such advanced work, it is a definite sign that he or she is definite¬ ly schooled in the A-B-C’s. (Continued on page 28) Modern Mechanix and

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Phone Amplifier Steps Up Voice for Hard of Hearing THOSE who are hard of hearing now may sit at their telephone and, by turning a dial, “step up” the sound coming through the receiver to a volume to fit their particu¬ lar needs. The new telephone amplification equip¬ ment, shown at the right, consists of an ordi¬ nary telephone, the control box containing the “peanut” vacuum tube and a small cabi¬ net containing a switch-key and rheostat. Batteries are installed near the instru¬ ment. The key switch throws the amplifier in or out of the telephone circuit so that the phone may be used both by persons with normal and those with impaired hear¬ ing. Scientists in the Bell Telephone labora¬ tories developed the tiny tube. Individual Fuses for Appliai which localizes blow-outs saves the handy-man the irritating task of havingtosearch through the fuse block for the cir¬ cuit that’s out of order. The plugs have self - contained fuses which blow open when the ....... . . particular appli- ncwwaU plulTas shown above* anCe *S servinS uses too much cur¬ rent. Thus only one appliance is discon¬ nected, while others on the circuit continue to burn. The fuse is a small glass enclosed cartridge which slips into the side of the plug as shown in the accompanying photo. Buzzer ^ Lights W srti of Soft Tire AUTOMOBILE drivers who like to keep a constant check on their tires will wel¬ come a new device which tells when any one of the tires has gone too soft for safety. A buzzer on the cowl sounds the warning, and one of four red lights on a panel on the dash tells which tire reached the deflation danger point. The tires, shown below, are equipped with special valve stems which close a circuit when the minimum pressure al¬ lowed by factory specifications is exceeded by five pounds. The closed circuit passes the electrical impulse to a collector ring in¬ side the brake drum, thence to dash. Inventions lor S e p t e m b 61

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Strange ^PERILS of (^Making fee7. by HOMER SCOTT Pioneer Underwater Cameraman IN 14 years I probably have gazed into the cold eyes of more curious fish and looked on the bodies of more actors and actresses beneath the sea than any other man. From the shores of Southern California to the rocky coast of the Socorro islands, far south in the Pacific, and even off the shores of New Zealand I have descend¬ ed many times in one of my half-bells, my legs dangling puppet-like in the cold water, to photograph dramas that sometimes thrilled me more than were the audi¬ ences that viewed the results on the screen. When the editors of Modern Mechanix and Inventions asked me to write of the thrills and tell you how these scenes are filmed, I said to myself, “Gosh, there’s nothing very interesting about undersea picture-taking.” But as I sit pondering the problem, it occurs to me that possibly I have had a privilege denied to all but a few men — to see human life mingling with the unknown beneath the ocean, to study native life beneath the sea, to experience death close at hand, only to escape with sec¬ onds to spare. How many times I have been plunged into the Pacific from the yard arm of some rocking ship I can’t even guess, i of But I remember one episode with a strange vividness. We has had gone one fine day to the waters off Catalina Island to record the finding of a prop treasure chest 50 feet below the surface. Above me, as I was being lowered away, Modern Mechanix and 62

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e^OVIES beneath Hollywood’s most intrepid cam¬ eraman relates startling adventures he has encountered making under¬ sea movies which chill your blood. the Sea stretched a nearly-new steel cable -which had been recently tested to a breaking strength of 30 tons. Down I went . . . ten feet . . . twenty . . . thirty. Then sudden¬ ly I shot downward. The cable had parted. I kept my legs drawn under me as I neared the floor of the ocean, drawing great gulps of air into my lungs for the long ascent to the surface, if, indeed, I could get clear of the bell. I knew I had only a few seconds, for the air line had parted and water was pouring in through the hose. Those on deck knew what had happened instantly when the weight was released so suddenly. Without pausing to consider his personal danger, I learned later, Fred, a prominent assistant director whom I worked with, grabbed one of the 80-pound weights and leaped overboard. The lead bore him down like a millstone, and within five seconds after I had struck bottom, I saiw his form looming up through the win¬ dow. Quicker than you take to read this sen¬ tence, he upturned the bell. This enabled me to slide out, and, with our lungs nearly bursting, we cracked through the surface a few seconds later where eager hands pulled us aboard the tender. Recently in filming “Beneath the Sea” I had occasion to work with one of the larg¬ est photographic diving bells ever con- Inventions lor September 63

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Workmen Fabricate Synthetic Ship’s Hull From Concrete and Wire Mesh strutted ^is^artiticial concrete* and^ire’mesh. structed for motion pictures. This bell, whose picture appears on these pages, was made of steel and stands seven feet, six inches high and measures nearly five feet in diameter. It will withstand water pres¬ sure at a depth of 180 feet, though this is four times deeper than I have ever filmed a human actor. Emergency flasks of oxygen stand ready for instant use in case the bell breaks from its cable and falls to the bot¬ tom of the sea. Like all such modern contrivances, it car¬ ries a telephone and a microphone, in order that the voices of the actors may be record¬ ed on the ship above. With a heavy flooring of lead, the bell weighs nearly two and a half tons. It rests in a frame of heavy steel straps. Every time I descend from a ship in a bell, I think the fish below must be amused to see my legs dangling through the open bottom. You see, I sit on a saddle behind the camera, which is mounted on a bracket. Though my larger bell weighs, after the 80- pound lead weights are attached to the outside hooks, nearly two tons, I must keep my feet free to walk around the bottom. Yes, sir! More than once I have walked along the floor of the Pacific with two tons of lead on my shoulders and my head in the big air bubble, which, by the way, helps support the great weight and makes such walking possible. Movie Set Goes Haywire On one occasion I had descended off the California coast for a scene which required me to walk beneath the bell, photographing the side of a prop ship which had been planted there several days earlier. The set around which I was working demonstrated better than any on which I have worked beneath the Pacific just how elaborate an undersea scene may be made. For weeks prior to our arrival there, workmen had been fabricating the side of the ship, heavy concrete moulded into wire mesh, with enough steel and wood to hold it upright in a mild sea. Near the center, below the water line, had been built a jagged hole, representing the results from a terrific impact. An actor was to crawl out of this hole, bearing with him treasure from the galleon. I descended and focused on the hole, awaiting the actor. We were not more than 15 feet down at the time. Just at that mo¬ ment a ground swell began to move inshore and, as I looked on in dismay, the set slowly toppled over, disintegrated and settled to the bottom. 64 Mode and

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Reflected by Mirrors , Sunlight Illuminates Underwater Movie Scenes and ship’s hull are illuminated by sunlight. Figure of Unfortunately the builders had not counted on the effect of salt water on the fastenings and had built the ship too quick¬ ly and of inferior materials. Fortunately, however, we had had seven days’ work on it already and scenes filmed earlier were made to answer the studio’s needs. In filming scenes of people, fish and inani¬ mate objects we never use lights. We are able, occasionally, to reflect sunlight onto our objectives. These are the ordinary brilliant reflectors, of silver or gold color, used in the studios and on location to bend light rays directly on the scene. Here, how¬ ever, they are lowered on ropes and poles into the water. Illuminating Underwater Stage Divers tell me, and I agree from long ex¬ perience, that lights generally are unsuc¬ cessful under water for the reason that only lights of great power can be used and these become so hot that they quickly burn out. I have tried to make my bells as livable as possible, for I spend many of my wak¬ ing hours in them. Many days I spend five hours below water on my little seat, focus¬ ing on new scenes, changing magazines, swinging back and forth with the tides. There in the dark I pan the camera around, tilt it up and down on its stationary tripod and otherwise handle it exactly as I would on a sound stage instead of in the depths of the world’s greatest stage — the ocean. Not only can I manipulate the camera easily, bvit with the help of people on deck can direct both people and fish. Human actors, of course, must be told before they dive overboard exactly what to do. Oddly, as far as underwater direction is concerned, we can guide fish more easily than humans. Ordinary stage lights are unsuitable for illumination of underwater ^scenes. Instead, huge silver and gold^reflectors, One afternoon I was dangling beneath the camera ship off the Cocos islands. We had been waiting several hours for fish. At last a big school of tuna appeared. Fred, on deck, warned me that we were easing in among the school. “Okay,” I replied. “Throw chums over the right side of the bell.” In a moment I saw the fish move in that direction. As soon as none remained with¬ in my vision I reported. “They’re off my starboard beam,” I said into the ’phone. “Toss chums in on my left and 20 feet in front.” I started the camera, knowing I soon would have a swell picture. There they came, these race horses of the sea, dashing to the meal as they would attack fiercely anything that might stand in their paths. (Continued on page 127) Invent it for September 65

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(MECHANICAL f Wonders «/^ENTURY of Progress” is the name given the 1933 Chicago World’s Fair, and the whole show is well named, for it is an exposition depicting the progress of man’s advance in civilization in the last 100 years. And this progress revolves almost entirely around the advances made in science and mechanics in that length of time. Every conceivable mechanical oddity worth displaying is on show, and each month during the course of the exposition Modern Mechanix and Inventions will dis¬ play for readers who are unable to view the fair an increasingly augmented series of unusual pictures to help carry the true import of the exposition. Among the most interesting entertain¬ ment novelties is an “Airplane Ride” which is shown in the illustration to the right. A series of loose roller coaster cars, with stub wings, is sent down a dizzy spiral half-tube, so constructed that the train of cars cannot roll out. Eclipsing even the famous Ferris Wheel of the 1893 World’s Fair is the modern “Sky Ride,” which bristles with engineering nov¬ elties. In thoroughly safe cable cars, one may ride a third of a mile through the air 200 66 and

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of Qhicago WORLD’S tyair feet above ground. The cables suspending the cars are kept in a straight line by a sys¬ tem of catenary suspension wires which take the usual parabolic curve out of the suspended cable-way. This cahle-way is supported from towers which are 100 feet higher than the Wash¬ ington Monument, and are nearly as tall as the Woodworth building. An observation tower atop each allows an observer to see three states at once — Indiana, Illinois and Wisconsin. Huge weights of concrete act as shock absorbers for the cables, and take up shocks that are caused by sudden gusts of wind. Inventions for September 67

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When MOTHER EARTH sas’-ffESSss When old Mother Earth bursts forth in fiery wrath there’s little puny man can do about it except run for safety. In¬ genious scientific instruments, however, can predict these volcanic outbreaks and thus warn when it’s time to start run¬ ning, as told in this authoritative article. SINCE the year 1500, when fairly trust¬ worthy records begin, 98 eruptions of 57 volcanoes are known to have destroyed the lives of 190,000 people. The enormous property losses involved in these outbreaks have never been estimated. Quite apart from the scientific interest at¬ taching to the study of volcanoes, the figures just quoted show that these features of the earth’s surface call for thorough in¬ vestigation for the practical purpose of mitigating their terrors. The scientific knowledge already ac¬ quired concerning them justifies strong to predict volcanic outbreaks long enough in advance to make them harmless to the lives of men. The average American probably thinks of volcanic dangers as remote from his p — sonal affairs. It is true that within 1 United States p nally active vc fornia, which h to^be VreckonedU wifh in3rfhe ;s. Several supposedly extinct in the future. Helens, in Wa tion in the mi Modern M e c ha ni x and

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Rainier and Mount Shasta emit heated va¬ pors, giving evidence that their interiors are still hot. Carbon Mountain, in Colorado, which has been emitting gas and pouring avalanches of rock down its slope for sev¬ eral months, may turn out to be a live and lusty volcano. What do we know today about vol¬ canoes that was not known by our fore¬ fathers? First of all, we know that a volcano is not an opening into a vast “molten interior” of the earth. The seat of volcanic activity is probably never more than half a dozen miles below the earth’s surface. The formation of liquid lava is supposed to be due to the local release of pressure — through movements of the earth’s crust, chemi- Inventions for September

Page 70

Lava in Active Volcanoes Boils Constantly, Heated by Escaping Steam Ks«5r,t:; points. When the pressure is released, the rock changes from solid to liquid, and its discharge is probably due, at least in many cases, to the sudden generation of steam from water in the depths of the earth. Apart from these general facts, a great deal has been learned about the mechanism of eruptions that bears directly upon the problem of prediction. Although a majority of earthquakes are not connected with vol¬ canic eruptions, local tremors and tiltings of the ground occur in connection with volcanic activities both before and during an outbreak. Hence the seismograph, or earthquake- recorder, is at present the principal instru¬ ment by means of which the volcanologist feels, so to speak, the pulse of a live volcano and gains an inkling of its future behavior. Thus it happens that at the famous Ha¬ waiian Volcano Observatory, near the cra¬ ter of Kilauea, the activities of that volcano and also of the distant volcano Mauna Loa can be followed more closely by the inspec- , made in the cellar of the observatory, than by actual ocular observation of the craters. The great eruption of Sakurajima, in Japan, in 1914, where no previous outbreak had occurred for 135 years, was predicted from the records of a seismograph in the neighboring city of Kagoshima. By the ad¬ vice of seismologists 90,000 people were re¬ moved to a place of safety before the erup¬ tion began and an immense loss of life was thus averted. Several other methods have been utilized with much success at Kilauea, Vesuvius and elsewhere in observing the changes that go on in the interiors of volcanoes and give more or less definite warning of impending outbreaks. Powerful microphones are employed for listening to certain characteristic sounds in the depths of the volcano. Movements of lava are detected by their magnetic effects. Underground temperatures measured at various points on the slopes of volcanoes show a marked heating of the ground be¬ fore an eruption. Chemical analyses of volcanic gases show changes of composition in advance of an outbreak. Organized arrangements have been made in some regions of frequent vol¬ canic activity for promptly evacuating the population from the danger zone when an eruption impends. 70 Modern M e chani x and

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Page 72

"Parachute” Wheel on Race Car Averts Blowout Smash-up brick speedway. MANY deadly disasters occur on the briek auto speedways when a rear tire sud¬ denly blows open. So with a view to pre¬ venting such smash-ups in trial runs of racing cars one prominent car manufac¬ turer has introduced a fifth whegl which takes the load when the regular tire flat¬ tens out. The “parachute” tire, as it is called because it performs similar to a para¬ chute, fits over a smaller wheel attached to the right rear wheel on the racing bus. The extra weight slows down the machine slightly, but it is not used in the regular races. World’s Tiniest Violins 2 in. Long BELOW may be seen photos of two of the world’s smallest violins. Master¬ pieces of craftsmanship, they are built throughout as genuine reproductions of the real thing. Each violin is 2 in. long, weighs 1V2 grams, and uses ebony for pegs and bridge. The G-chord is of silver. Two months’ hard work went into the construc¬ tion of each of them. New Tester for Radio Service Men THE last word in efficiency and flexibility in radio set testers is offered in an “all¬ purpose” instrument manufactured by a prominent radio company. With this in¬ strument at his disposal, the radio service man can almost instantly locate defective parts, open circuits, etc. Apparatus is car¬ ried in a small self-contained cabinet and is thus ideal for house-to-house canvassing. Tent Latest Thing in Inflation CAMPERS will be quick to appreciate the conveniences offered in a new tent hav¬ ing no poles, but using inflated supports instead. When you wish to pitch camp for the night you simply bring a tire pump into action and after a few dozen strokes the tent begins to take shape, as illustrated in the photo below. The shelter has all the sturdi¬ ness and dependability of a pole supported tent and may be erected in less than half the time. Shock Absorbers for Wrist Watches A RADICALLY new departure in wrist watches is represented in a timepiece which inventor claims is completely shock- proof. The move¬ ment is mounted inside an outer shell and insulat¬ ed against shock by means of four tiny springs, indi¬ cated by the ar¬ rows in the ac¬ companying pho¬ to. In severe tests recently thewatch was dropped from the top of a three- story building without slightest ™appha«5f,mt0 the mechanism. when watch falls to the floor. 72 Mode. M e chani . and

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Mechanical Cow Shows How Live Ones Manufacture Milk THE physiological process whereby a cow manufactures milk from the grass and other materials she eats is demonstrat¬ ed by an amazing mechanical cow on display at the Chicago Century of Progress Fair. A cut¬ away view of the cow’s innards shows by a series of pipes the route of the materials which go into the making of milk, while small hu¬ man-looking' characters demonstrate the chemical changes which take place in the various organs. Each function is labeled plainly to enlighten visitors on the milk¬ making procedure. Heat on Neck Cures Sea-sickness NECK heaters as a remedy for sea-sick¬ ness or air-sickness are suggested by a French scientist. The idea of the treatment is to heat by electric treatment the small bulb of nervous tissue called the medulla oblingata, inside the back of the neck just at the junction between the spinal cord and the brain. In tests employing a new medi¬ cal process known as diathermy, sea-sick¬ ness, car-sickness, and air-sickness and all similar conditions were relieved at once. Orphans Win Toy for Heroism Orphan boys who saved lives of 500 people by preventing STUMBLING, struggling for breath through a terrific thunderstorm nearPassiac, N. J., six orphan boys, waving, screaming desper¬ ately stopped an Erie train fifty feet from a washout and saved the lives of 500 pas¬ sengers. The story of their heroism made front page news throughout the nation, and as a reward the boys won a railroad of their own. The road has three miniature trains like the one shown in the photo above, and is complete with tracks, switches, signals, miniature stations and other buildings to go along their railroad’s right of way. Copy Detective for Safe Driving USEFUL applications of detective story technique to safe automobile driving are suggested by the National Safety Coun¬ cil. One instance is cited to illustrate the point. A bus driver who must have known his Sherlock Holmes was approaching a cross street when he suddenly slowed down for no apparent reason. Just as he reached the corner a speeding truck appeared from the side street, where it had been invisible. A collision was avoided. The bus driver ex¬ plained that he had seen a pedestrian hurry to reach the curb and had deducted that some vehicle invisible to himself was ap¬ proaching. Lapel Mike Latest in Flexibility A TINY micro¬ phone for use at banquets, con¬ ventions, etc., is only one and one- quarter inches in diameter and fast¬ ens securely to the coat lapel by a clip on the back. The mike, manu¬ facturers claim, is so unobtrusive that the speaker forgets about it and makes a speech free of self - conscious¬ ness. It permits complete freedom of movement and expression and does not greatly interfere with Mi(l6et mika fastens or sleepers. with a small pencil Inventions for September 73

Page 74

Hot-Buttered-Corn-on-the-Cob-5c! A young fellow, a real go-getter, attracted considerable attention (and coins) at a popular summer resort on the New Jersey coast. He had a portion of a boardwalk store for his place of business and was do¬ ing a better business than the store from which he had rented his small space. He ran a Hot-Buttered-Corn-on-the-Cob coun¬ ter. He bought the corn from a farmer at a much lower price than he would have to pay at a retail grocery and sold it at 5c per cob. Over his stand he had a large attractive sign in red letters which read: Hot Buttered Corn on the Cob 5c and people were buying the corn from him as fast as he could hand it out! The de¬ licious aroma of the corn hung over the entire boardwalk and did all the selling job necessary! Bees Net Good Income A jobless Colorado man has made a good income during the depression by working with bees. Establishing an apiary near the city limits he sells bees, frames of brood, and queens, and teaches people, who want to help defray living expenses by having 1000 ‘Ways to Here again this month Modern Me¬ chanic and Inventions sets forth a group of money-making ideas that have proved their practicability at the task of bring¬ ing in a depression income. Look the list over carefully — one particular item may suit your needs and conditions to a T. their own honey supply, how to care for bees. He cleverly places hives of bees on city premises, in garages, houses, and yards, where they will not be objectionable to neighbors. He drives through the rural district buying and selling bees, honey, wax and apiary equipment. During the dull season he helps other apiarists prepare bee supplies. Delivery Service for Merchants Realization that many grocery stores and meat markets had been forced to discon¬ tinue their individual delivery services en¬ abled one enterprising man to acquire full time employment at good wages. He ob¬ served that these stores in effecting the economy of no delivery overhead had lost the trade of many people. Approaching the proprietors of a number of these stores he made them a proposition to deliver their orders twice a day at no cost to them, the small delivery charge of ten cents being paid direct by the customers who desired the special service. It did not require much persuasion to line up a goodly number of merchants. Large display cards were fur¬ nished the stores explaining the delivery service. Ironboard Cover Holders One man earns a good living making and selling holders for ironing board covers. He found that housewives were greatly ap¬ preciative of a device or gadget that would enable them to quickly change ironing board covers, or replace a scorched one. These holders he has found to be easy to make and they sell readily. Short lengths of No. 8 copper wire have their ends cut

Page 75

Make a Living slanting to form sharp points; the wires are then bent into V-shapes and the sharp¬ ened ends curved to form claws. A short length of light coil spring, attached between the two claws, completes one holder. A set of five holders sells for twenty-five cents and costs about three cents to make. Ocean Floor Sight-seeing A youngster in Florida who built a div¬ ing helmet from plans given in June Mod¬ ern Mechanix and Inventions is earning a neat little income by conducting an under¬ water sightseeing agency on the end of a pier near a swimming beach. A sign stuck up on a post by his concession draws dozens of customers curious to see what the bot¬ tom of the ocean looks like. While the sight¬ seer traipses around under the water, the concessionnaire mans the pump on the pier and looks after his customer’s comfort and safety. 10 cents is charged for a 15 minute descent. Shopping News for Merchants An elderly Buffalo business man who had lost his position struck upon this idea of making his living while reading the ad¬ vertisements in a local newspaper. He de¬ cided to publish a weekly shopping news featuring all the large department stores of the city and advertise their sales for Fri¬ day and Saturday. He then solicited ads from these large stores at a great reduction from the advertising rate of the daily pa¬ pers. The shopping news is published each Thursday and is distributed free to every family in the city. After the appearance of the first edition of his publication he was unable to take care of all the merchants who wanted ads placed in the new medium. This man is now making an enormous weekly income and has a whole staff of men working under him. Hobby Pays Money An unemployed man in New York has developed a living from his hobby. He had always been fascinated by tinkering with clocks. Shut out of his regular line of em¬ ployment, he found that in almost every home there is a clock that either would not run, or else ran incorrectly. The average person will take his watch to the jeweler for repairs but it is very seldom that any one is found who relishes tucking a bulky clock under one arm and marching it down the street. Playing on this natural charac¬ teristic of people this former grocery store clerk is now making a very profitable living as a traveling clock repair man. Money Cutting Glass Designs With a small portable electric motor (1/6 to 1/12 h. p.) , a flexible shaft and a glass cut¬ ting emery wheel, any workman who is a fair penman and at all artistically inclined, can, with a little practice, cut simple pat¬ tern and designs on glass ware. At first it Inventions lor September may be necessary to trace the designs on the glass but the most attractive work will be turned out when sufficient proficiency is attained to be able to work free-hand. With such an outfit jars and bottles may easily be converted into attractive cut-glass articles. Also one may buy plain vases wholesale and cut designs on them. Mimeographing Advertising and Letters Practically all kinds of businesses have occasion to send out letters advertising some new item or new prices as well as calling customers’ attention to old accounts and informing their best patrons about style and price changes. This applies particular¬ ly to small concerns who do not have exten¬ sive advertising budgets and must make every advertising penny count to the ut¬ most. Mimeographs or other duplicating ma¬ chines may be had on such easy terms these days that a very little amount of work will provide one with the necessary payments on the machine and a margin of profit that grows as work is solicited. Most establish¬ ments, especially the smaller ones appre¬ ciate a reliable man who contracts to handle this work. Bug Chasing for a Profit One man makes a good living by calling on people whose yards have nice attractive shrubbery, and offering to spray the plants periodically to rid them of the insects which are found on most plants. Many species of bug will kill the plants if not ex¬ terminated. A good tobacco powder can be bought at hardware stores for 25c per pound and when boiled in two gallons of water will spray several jobs. A good spray gun for hand use can be had at very low prices. After doing several jobs effectively this man has had no trouble in profitably using all his time. The charge is usually fig¬ ured on a time basis — a $2 job netting about $1.50. 75

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Plumber Uncovers Spare Dollars A jobless plumber in Omaha has suc¬ ceeded in earning a living for himself by showing apartment house owners how they can overcome loss of rentals on their top floor apartments during hot months — a problem which every apartment house owner knows only too well. His plan con¬ sists of laying perforated pipe on the roof so a fine and continuous spray can be thrown over the roof on hot days. The re¬ sulting evaporation causes a reduction in temperature of from 12 to 15 degrees throughout the top floor. The gain in satis¬ fied renters during one summer offsets the cost several times over. This idea has been utilized very effectively by a large roadside restaurant in Los Angeles and a Santa Bar¬ bara hotel varied the idea by laying a pipe on the ground around the building through which a spray was shot up around the building on hot days. Replacing Unsightly Aerials The unsightly appearance of most of the radio aerials in his neighborhood gave one Detroit man an idea that has netted him many dollars since. Unattractive poles or aerial rods perched upon an otherwise beautiful home, can do much to detract from its appearance. This ambitious man agreed to remove these ungainly aerials and replace them with ones that circled the house in a protected, inconspicuous path underneath the eaves. A flat rate of five dollars was charged for the service of re¬ moving the old poles and wires and replac¬ ing them with the new type installation. Most of this sum was clear profit, as usually the old wires and insulators could be utilized. Prospective customers were first ap¬ proached and shown photos of homes be¬ fore and after the new aerials were in¬ stalled. Usually when the advantages of the new over the old were told — such as less 76 danger from lightning, better reception in bad weather, better protection from high winds — a sale was made and another per¬ son was added to his waiting list of cus¬ tomers. Ice Blankets for Sale! In Montreal a young man has discovered that not every housekeeper can afford an electric refrigerator and has to keep to the old system of buying ice. To these people the young man demonstrates what he calls an Ice Blanket. This he has made out of a three-foot square of outing flannel which he dips in a good grade of paraffin oil and then runs it through an old clothes wringer. When he has removed all the oil he can he smoothes out the flannel squares and folds and seals each in a cellophane envelope along with some colored advertising mat¬ ter which can be read through the wrapper and which also gives his name and address and phone number. He guarantees that each Ice Blanket will save its cost in ten days’ time if used ac¬ cording to the accompanying directions. The Ice Blanket, when placed around the cake of ice in the'refrigerator, excludes all air and prevents such rapid melting, mak¬ ing two cakes of ice last as long as three or more ordinarily. These Ice Blankets cost him fifteen cents each complete with envel¬ ope and advertising matter and sell readily at fifty cents. Tropical Fish Are Profitable Tropical fish are quite unknown in most communities as yet although they have been raised successfully for many years. These little fish are easy to raise, low in price and sell fast. Simply procure several pairs, a few plants, a modest aquarium (which is easily constructed at home) and the fish will soon profitably multiply. There is an increasing market for the fish, as well as the plants and complete outfits. A more ambitious project, along the same line, is a tourist museum or glass enclosed rock gar¬ den. As a nucleus for such an old green¬ house is ideal and many are idle at low rent. The idea of a tropical garden can be sold to an enterprising greenhouse proprie¬ tor as an added attraction to his business. They never fail to interest young and old. Use for Old Phonograph Records Old phonograph records have for years constituted a challenge to the ingenuity of those trying to find a use for them. Here is a method that will profitably dispose of as many as you can buy, beg, steal or borrow ! Take a two-quart pail, turn it upside down in a hot oven and on it place one of the old phonograph records, correctly cen¬ tered. When the record becomes thorough¬ ly heated, its over-lapping edge will turn or “mold” down over the upturned pail, and when cooled off you will have a very novel flower pot, complete even to the hole in the bottom! Using different shaped objects for “molds” under the records the finished jobs can be made to have a variety of shapes from the conventional flower pot shape to flat trays with shallow edges. Modern M e chani x and

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Whitewashing Trees Whitewashing trees for neighbors nets a sizeable income for an unemployed man in Akron, Ohio. Only a small investment is re¬ quired — sufficient to purchase a whitewash brush, a pail and a small quantity of the following materials: Unslaked lime, com¬ mon salt, rice flour, Spanish whiting and glue. Most promising prospects will be found among people who are proud of the arboreal ornamentation of their lawns. A flat rate of 25 cents a tree will yield a neat profit. Moving List Service A young man, unable to find othei created his own job, and has been his way by selling a “Moving List S Twice a week he secures from m< transfer companies a list of the n _ addresses of all the people who have n__ _ , new people who have moved into the city, and the addresses to which they moved. From these he compiles a consolidated list, and runs off on a mimeograph as many as he requires for his customers, who are laundry drivers, milkmen, bakery men, coal men, ice men, cleaning establishments, gro¬ cery, meat and radio men. In short, any firm that depends upon selling their com¬ modity or service regularly at the home, and so are always on the watch for new customers. Knowing the name of the new¬ comer before making the “approach” gives them an advantage over having to go “cold” to the new occupant. For the service he receives three dollars per year from each customer. Home Town Cook Book The home town cook book is a particu¬ larly good money making project and has been successfully worked in many locali¬ ties. Recipes are contributed by as many local. women as can be solicited and the pro¬ moter sells advertising space, the cost of which is based on advance estimates of the printing expense. A minimum circulation is guaranteed to the advertiser, and the printing is done on serviceable but not ex¬ pensive paper. It is customary to secure as many contri¬ butions as possible, each housewife giving her favorite recipe. To personalize the project, credit is given to the contributors. The books are usually sold at fifty cents each. The contributor naturally will pur¬ chase one or several of the books to see their names and recipes in print, and clubs, church societies and other women’s organi¬ zations, when given a liberal commission (usually 50%) often sell hundreds of them. Office Housecleaning Business and professional men seldom consider the difference a good washing job will make in the appearance and atmos¬ phere of their offices and surroundings. A former store clerk, with this idea in mind, called on several men and obtained the Work of washing down the walls. Most business men welcome the suggestion, par¬ ticularly as it can be done at a very reason- Inventions for September times a year, and already has a regular clientele. A small ladder, an ordinary bucket, a sponge and a can of paint cleaner is all the equipment that is needed. About ten cents for every twenty-five square feet of surface cleaned will net a neat sum from any job. Containers for Newspapers An enterprising newsboy has been mak¬ ing neat wooden boxes for receiving the daily paper. The box is dimensioned to take the folded paper and is just a bit longer than the width of the sheet. The papers are slipped through a slot in the end of the box, while some of the boxes have hinged tops. He carries a sample with him on his route and contracts to install one to a cus¬ tomer for fifty cents. This price includes painting it the color of the customer’s house and attaching it at a conveniently designat¬ ed place. The boxes keep out rain and snow and prevent papers from being blown away — thus insuring a neat and clean daily paper. CASH FOR MONEY-MAKING IDEAS ! 77

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78 Modi M e c h a n i x and

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Inventions for September 79

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improve your Accuracy at 23 ait Casting ANY boy who has tossed an apple from the end of a stick, or beaten a rug, can easily learn how to master the art of bait casting. And who will gainsay the fact that bait casting is a more pleasurable di¬ version that such dismal and monotonous jobs as carpet beating, for instance. Anglers who are skilled fly or bait cast¬ ers invariably get more kick out of their sport than fishermen who use cruder methods. The secret is in the skill of plac¬ ing the lure accurately in the spot de¬ sired, thirty, forty, or even a hundred feet away. In bait casting the reel does most of the work; the rod is just a sort of stick, with line guides, to give leverage to the cast. Consequently, the reel should be a quad¬ ruple multiplying, 110-yard capacity, and preferably anti - backlash, level - winding device, made of good quality materials. If the reel does not have a cork core, a discarded line (or 10c store twine) should be wound on the spool until it is half filled, in order to facilitate “thumb¬ ing.” Then attach the braided silk line — 12-lb test for a five-ounce rod; 18-lb. test for a six-ounce rod — looping the line around the spool and fastening. Now to learn casting it is not necessary to go fishing. A lawn or city park will do for practicing. If practicing on a lawn, use a bicycle tire or a newspaper for a target; if on water, anything that will float. The target should be about forty feet away. You should strive for accuracy in cast¬ ing rather than for distance. Clamp the reel to the rod handle, thread the line through the guides, then attach the end of the line to the weight. A dipsey sinker will do in lieu of a tournament plug. Now standing erect, with feet close to¬ gether, left arm down, grasp the rod handle, reel up, with the right hand, and keeping the elbow close to the side, prac¬ tice the wrist movement shown in the accompanying illustrations, holding the (Continued on page 126) Modern Mechani

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Prize cAW ARDS in (gyroscope Cover $50 CONTEST The best letter in our June Cover Contest in answer to the question "Can This Man Fall?” was submitted by Emmett Healey, of Delano, California, who wins first prize of #15 with his clear, terse summary. Balance of awards, together with illustrative letters, are listed below. FLOOD of letters from all over the world proclaimed intense interest in our June Cover Contest, wherein $50 has been awarded, $15 to the winner, $5 for the five best letters, and $2 for the next best five explanations. Emmett Healey, of Delano, California, submitted the most terse, clear, and accu¬ rate synopsis in answer to the contest ques¬ tion, “Can This Man Fall?” The cover depicted a tight rope walker on the high wire, supposedly kept in per¬ fect balance by a double gyroscope carried at right angles to his line of march. Winners of $5 awards were W. G. Ernst, U. S. Naval Air Station, Norfolk, Va., Homer Baldwin, of Columbus, S. C., E. B. Norman, of Monrovia, Cal., A. C. Thurman, of Rich¬ mond, Cal., and Earl R. Martin, of Urbana, Illinois. Winners of $2 awards were Andrew Vena, New York City, Garen Roush, Letart Falls, 0., Burton K. Patton, Brooklyn, N. Y., Jesse Harris, Richmond Hill, N. Y., and C. J. Armstrong, Houston, Texas. The substance of most of the letters was that the gyroscopes would keep the aerial- ist from falling, which opinion is in error. The letters awarded prizes all were cor¬ rect in saying that the ’scopes could not prevent the man’s falling, as nothing yet has been discovered which will refute the power of gravity. Once off the rope for any reason, the man would fall like a plummet. The gyroscopes, however, will greatly aid such a stunt, and would enable a man to traverse dizzy heights with much more safe¬ ty than is now gained with the well known pole, or umbrella. The point most were unanimous on was that the wheels should rotate in the same direction. Mr. Healey contends that they should be in opposite rotation to minimize torque and to complement precession. This is true, but as far as the actual precessing is concerned the judges were of the opinion that the wheels might rotate in the same direction, or opposite directions. A model was made to prove the point. A gyroscope will not precess as long as the wheels are moved in their plane of rotation — that is parallel to the face of the wheel. This means the aerialist can move forward, back- ( Continued, on page 25) ions 1 1 Septembe 81

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Tutting TLANES through Light Plane Fans, Attend Ye! Here’s the inside story of the N.A.C.A. Laboratory by an Air Service lieutenant who knows what he is talking about. Lieut. McDarment lists developments now under way in this ultra modern design laboratory, which is so huge it has a wind tunnel capable of wind-testing full size airplanes! A NOISE which began like the low rumble of an earthquake gradually swelled in tone until the whole atmosphere over the Langley air field trembled with the vibra¬ tion. “What’s that unearthly howl?” asked a visitor of an aviator who was guiding him around the big Virginia air base. “That,” replied the aviator, “is an air¬ plane being put through the third degree on the operating table of the giant wind tunnel of the N.A.C.A. They test the strength — or weakness— of planes there.” “Are visitors allowed in this — this N.A.C.A. ?” “That’s short for National Advisory Com¬ mittee for Aeronautics,” the aviator ex¬ plained, “and visitors are allowed, but most of the work there is of a confidential or secret nature until finished.” Largest Wind Tunnel in World And what the aviator said is true. Here in this fairly secluded section of Virginia is the most important aeronautical labora¬ tory in the world and the work is mostly secret or confidential. The “big shots” of aviation compose this aeronautical com¬ mittee. They live all over the country. But the real engineering research work is done by skilled civilian technicians at the lab¬ oratory. The most outstanding feature of the 82 Modern Meehan i x and

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the c&hird r Degree McDarment laboratory buildings is the giant wind tun¬ nel — the largest in the world. Into the huge mouth of this tunnel whole life sized air¬ planes may be stuffed, and when the four thousand horse power motors begin to spin the eighteen foot propellers, a roar is set up like distant thunder or an approaching earthquake. And an airplane takes a beat¬ ing. Gales Test Strength The airplane is securely tied down in front of the maw of the great tunnel while a blast of air with a velocity of 150 miles an hour lashes its wings, elevators and ailerons. Unless the plane is pretty strong pieces will be torn off like a western cy¬ clone strips the feathers from a chicken. A man cannot stand up in such a gale. If he were propped up in it his clothes would be torn off, his eyelids puffed up like little balloons and he might literally drown in air. Aviators of course attain speeds much greater than this, but they are protected by goggles and shields. The object of this wind tunnel and the other interesting test appliances at the laboratory is to get the “low down” in cold mathematical figures of all aeronautical equipment. The Government wants to know the breaking point of metals, the stalling point of certain planes, the flash point of oils and fuel, and a lot of other things that a layman would never think about. When¬ ever a plane manufacturer declares: “I’ve built the best plane in the world and I’d like to sell a batch of them to the Govern¬ ment,” the officials may reply: “That’s fine, we’ll take a sample plane and give it the third degree in the N.A.C.A. wind tunnel and get the figures on it.” And into the tunnel will the new plane go. It will not be merely set up into flying position and gently kissed with a breeze, but will be blasted with full force back¬ wards, sideways, and upside down. If the plane has any “rheumatic” joints they show up. When a plane is trussed up for the tunnel it goes like a patient to an operating table. Little instruments are stuck all around over it, but instead of testing heart, liver, lungs, grunts and groans as doctors do a human patient, the instruments show the s f, September 83

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Elaborate Towing Carriage Is the Only Route to Accurate Hull Desigi thousand foot runway filled with water is equipped with an automatic electric light weight carriage capable of recording planing efficiencies by actually testing the models to be designed. Above is a seaplane float rigged for testing. twists, turns, strains, bends and breakage or stalls of the plane. Sometimes a plane is found to be afflicted with high stalling speed instead of high blood pressure as with a human patient. Aviation’s Best Minds on Committee Many of the internal “ailments” of a plane do not show up readily to the eye during the strenuous diagnosis in the tun¬ nel. Some of the minute fractures, tears or metal fatigue will be found in later micro¬ scopic examinations. These are the things which sometimes give way in the air when an acrobatic flyer least expects. The lab¬ oratory shows up all these little things and written reports are furnished to the people who need and are entitled to know them. The data is dished out in hard, cold, scien¬ tific figures and statements. The men who diagnose the ills of air¬ planes and motors in the big Government laboratory are highly ed¬ ucated and skilled tech¬ nicians. Some of them are Doctors of Science and several others have a string of college de¬ grees after their names a mile long. The techni¬ cians are civilians but many of them hold commissions in the Reserve Corps of the Army, Navy or Marine Corps. On the big committee which rules the laboratory are such names as Dr. Ames, President of Johns Hopkins University, Dr. Abbot, Secretary of Smithsonian Institu¬ tion, Dr. Durand of Stanford University, Col. Charles A. Lindbergh, General B. D. Foulois, Chief of the Army Air Corps, Or¬ ville Wright, E. P. Warner and Gen. H. C. Pratt. An aura of higher mathematics pervades the offices of the technical men in the big brick laboratory building at Langley. Desks are covered with blueprints, graphs, logar¬ ithm tables and ponderable looking for¬ mulas, resembling Einstein’s theory of relativity. In fact one of the experts re¬ cently in figuring out the strength of a hollow tube used three dimensionless va¬ riables tied in with the mathematical law of Least Squares. Actual Flying Done, Too A steady amount of actual flying goes on in connection with the N.A.C.A. laboratory tests. But the mathematical boys do not go out and put planes through their paces in the air. Maybe they are too good at figuring percentage to take up actual flying. The 84 Modern Me chanix and

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Smoke Photos Show Remarkable Effect of Slots on High-Climb Planes At high angles of incidence (high climb near the stalling point) the air tends to break away as the above test photos show. By putting an auxiliary wing ahead of the main plane, the air is kept from burbling and thus stalling points are raised. A plane can climb better with slots. men who do the flying are not dumb but they would not take any first prizes in higher mathematics. It is often said that a mathematician would not make a good aviator because he might start pondering over coefficients and variables in the air and forget to work the ailerons and eleva¬ tors of his plane. The actual flying supplements the work of the big wind tunnel. It also helps give a practical side to some of the findings of the technicians. One of the laboratory men will make a discovery with his for¬ mulas and the new idea may be tried out on a plane in the air. For example, the landing speed of a plane with a certain wing curvature and load figures out to be a definite speed. A wing of that sort may be put on a plane and a test made. The reaction of certain shaped control surfaces is also tested against the laboratory figures. Frying Pan Gadgets The Army aviators at Langley Field are accustomed to seeing airplanes of queer shapes and sounds arise from the N.A.G.A. hangar and sail into the air. Planes with slots and flaps on the wings, also “spoilers” are a common sight as well as an autogiro hovering with no forward motion over the field. Sometimes an airplane may be seen flying along over the N.A.G.A. area with an apparatus that looks like a frying skillet on the end of a clothes line dangling below the fuselage. But a closer inspection will reveal it to be an instrument recording some peculiar movement of the airplane. Anything new in the aeronautical world may be tested at the N.A.G.A. laboratories but the work is not all confined to the new developments. Old, tried and tested principles have come in for a share of sus¬ picion under some of the new findings in the scientific world, and the laboratories are equipped to tackle these to see just how much water they hold. The newly announced paddle wheel air¬ plane — a plane having big paddle wheels for wings has been under study at the (Continued on page 130) Inventions lot September 85

Page 86

Walking Stick Unfolds Into Picnicker’s Dining Table lunch counter, the end being thrust down in the ground as shown. When lunch is finished, fold up and strike camp. Oil Tank Has Scientific Shape AN EIGHTY thousand barrel oil tank, now in operation at Longview, Texas, has a shape which closely resembles a drop of mercury on a flat surface. Since the drop of mercury does not col¬ lapse and the surface tension is everywhere the same, it follows that the shape of the drop must be such as to conform to these equal tensions. This tank, shaped exactly like a drop of mercury, has the weight distributed equally over the entire surface. The structure weighs five hundred thou¬ sand pounds, or about sixty thousand less than a standard tank of the same capacity. It was the first tank of its size to be welded. DEAL for campers, picnickers and hikers is a new utensil now on the market which provides the facilities of a walking stick and dining table. Six dishes of food can be laid out on the six shelves, which un¬ fold from the straight section of the device. When you wish to pitch camp, simply jab the point into the ground and unfold. Flexible Conduit From Door Spring F MAKING a re¬ pair on a wash¬ ing machine re¬ cently, the writer was called upon to find some sort of a flexible con¬ duit that would not only protect the cord from twisting but in some measure al¬ so from the water. Ordinary con¬ duit was too stiff for the purpose and funds were not available for the more expen¬ sive nickel-plated material. So it was found that a ten cent screen door spring was just right. To use such an article for this purpose, it is first necessary to clip Off both ends. No danger of wire breaking It is then only when it is sheathed in old necessary to push door sprmg and ,aped a* ands- the cord through. If it is desired to pre¬ vent the spring covering from slipping out of place, friction tape may be used. Sharp bends and consequent breakage of insulation is prevented by the spring sheathing. Modern Mechanix and Shaped like drop of mercury, this oil tank has weight distributed evenly , 86

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fortunes Waiting for inventors there has never been a time in human history j that has been more ad- vantageous to the inven- [Vur tor. There are in America \ today at least 20,000 man- \ ( P°x, ufacturers looking for \ pOT JW. new ideas; little ideas > — - that will bring greater - ; - activity and greater Toys often yield a for profits to their plants. for a velorj mKm nanas? What is needed is a device for peeling bananas in hotels, restau- V- rants and soda fountains. - - It should be something through which the ba- /4 O nanas are merely pushed (fJvM/fll and they should come out, completely peeled, on other side; an operation not consuming over 3 seconds of time. ' Such a thing could be - * I easily worth $50,000 cash. ne— a put-put-putter Milady’s toilet is badly g handsome rewards. jn nee(J 0f a new acces¬ sory; not exactly a new accessory but an old accessory in new form. The perfume and toilet water atom¬ izers now used have as their active and main principle a small rubber bulb which is squeezed to bring about atomization. The action of the alcohol in the perfume and the toilet water is very bad on this rubber and it soon becomes dull and hard, finally breaking. What is wanted is an all-glass and metal atomizer without a rubber bulb. To the man who has enough artistic taste and mechanical ingenuity to improve this little device will go a large fortune. Every year there is used in the United (Continued on page 13b) 87

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HAND I KINKS Do you know any short-cuts or handikinks which readers of these pages would find valuable? Send your ideas in to the magazine; if they are new and novel you’ll receive a check in payment at regular rates. Water Clock Tells Correct Time THE simplest form of time-piece, outside the sun dial, is this modification of the ancient water clock. All that is required are a coffee can, float and a graduated bar. How these parts are assembled is illustrated in the accompanying drawing. For the flat bar, a section of pine yard-stick can be sandpa¬ pered clean. Be sure the stick slides freely in the slot in the lid. To calibrate the clock fill the can with water and at the end of each hour mark the stick. Graduations will not be evenly spaced because when full the water drips faster than when nearly empty. — Hi Sibley. U nleash Dog From Bedside ~'N MANY communities it is necessary to keep dogs confined at night, but in case of prowlers the householder earnest¬ ly wishes to release them - 1 without going out. So here’s an extremely simple unlatching device that works out beautifully. It is operated from the bed¬ side, for a distance up to 100 feet. First drill a small hole in the floor near the bed and baseboard, taking care to locate it within an inch or so of a floor joist. Under this hole install an angle bracket as shown, so that wire will not need to turn a corner, and string under house through screweyes to the floor joists. At the other end connect to a latch on the door to be opened. The dogs will lose no time getting out. — Donald Cooke. Darkroom Clock Light Operates on Six Volts CAMERA fans will be quick to perceive the value of this little dark-room light which illuminates the photographic timing clock. Any junk yard will furnish you with an old-style hooded dash light such as is com¬ monly used on old Model T Ford cars. To the socket attach a couple of wires from the door bell transformer, then mount the socket on a shelf so that it throws a shaded beam of light on your timing clocks. To render this white light non-actinic upon photo printing papers, plates and films, procure several pieces of heavy sheet celluloid — one red for ordinary plates, one green for panchromatic negatives, and one amber for printing pa¬ pers. These strips of colored celluloid are then cut to size, wound and glued in cylin¬ drical form to fit inside the metal shade of the dash light. The result is a subdued red, green, or amber non-actinic light inexpensive to operate. With white bulbs they can be used for many lighting purposes. — John E. Hogg. Mode Mech

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Items oS General Interest Clothes Hangers for Closet Tops rpHE upper portion of high-ceiling closets is A usually wasted space. A good way to make this region available for use is to install a clothes pole near the ceiling of the closet in addition to the regular one lower down. Then by fastening a short pole (broom-handle) onto ordinary garment hangers, clothes can be al¬ most as readily hung up and taken down from the upper pole as from the lower one. The upper part is, of course, specially useful for j hanging unseasonable or seldom-used cloth- . ing. If the hangers have cross-bars for | hanging skirts or trousers, set the pole I handle at an angle so as to leave clearance J between it and the bar. Consult the draw- ing at the right for details. — James Thomas. H Novel Display Signs for Delivery Trucks ^ A NIMATED objects always catch the eye, and hence III -tX this little display sign for delivery trucks, involv- l ing as it does the use of a couple of rotating vanes, Ilk should get a lot of attention. On each side of the M body of the truck is painted a large Dutch wind ■ mill, and through the head of the mills is passed a ■ shaft. Then to the ends of this shaft are attached ■ a couple of vanes as illustrated at left. As the car H speeds along, the vanes twirl furiously, compelling V attention from everyone in the — ^ 1 fl vicinity. — Elbert Masson. // How to Motorize an Old ® Sewing Machine WHM dollars. The drawing at right shows how it may be done. A small beveled wheel and a fractional horse¬ power motor, preferably a fan motor, constitute the needed materials. The beveled wheel is secured to the shaft of the motor, which is then mounted in such a position that the wheel rotates against the flywheel of the sewing machine. A foot rheostat will have to be inserted in the line to govern the speed of the machine. Any sewing machine shop will sell you such a rheostat. — Chester Sullivan. Feathering Rudder for Shallow Draft Boats fpHE rudder of shallow water boats generally gives A a lot of trouble, but this can be eliminated by the use of the self-feathering steering apparatus illus¬ trated at the left. When you beach the board or strike a bar, the rudder automatically folds up and thus keeps out of harm’s way. First step in contriv¬ ing the self-feathering rudder is to slot the tiller post. Then between the two cheeks pin the rudder, which is finally weighted with a piece of iron to keep it down when not reefed. This arrangement is ideal for rowboats and small motorboats. With it you can navigate any kind of water and forget the rudder. A good coat of paint will make a lasting job. — Erich Bluss. 89

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Labor-Saving Workshop Stunts Hammer Die Punch for Workshop A CLEAN-CUT hole may be punched through 3-16 in. iron, gaskets, shims, in¬ ner tubing, etc., with this easily constructed punch. The materials required can usually be found around the garage or farm shop. The bottom part of the frame should be made of steel capable of taking a temper, as it contains the die hole. The shaping can be accomplished by clamping the heated mate¬ rial in the vise and turning the bends with a hammer. After drilling the die hole in the bottom, place the piece in the forge and bank the fire so most of the heat will come through the die hole. Heat till material around the hole is a bright cherry red, then quench in cold water. The punch is made from tool steel tem¬ pered as explained above. The ring should be welded onto the punch in the customary manner. It is cut from punch material squared up, 1% in. long. See that the lower end of the punch fits in the die hole without binding. The spring is a heavy tractor valve spring 5 in. long. Note that the gauge pin permits punching equidistant holes. — Earle Grinding Short Screws Is Easy With Holder ILLUSTRATED at the right is a little holder which makes the filing of short screws easy. A piece of wide corset stay or a strip of steel box-binding tape will do for material. The holder shown is drilled with Nos. 9, 18, 27 and 31 wire drills to take Nos. 10, 8, 6 and 4 machine screws. Fingers are protected and a better all around job is done.— Walter Brixius. Simple Clamp for Gluing THE butts of cast-off hinges are excellent material for the making of dog clamps. How they should drive - 1 be shaped is illustrated in the accompanying draw- 3 a5o?n? ' ing. Note that the slanted sides of the clamp are driven in across the joint to hold the ends firmly to- gether. Plastic wood will plug the holes left. It’s ad- visable to drive OLD roller bearings of the long type make excellent belt guides when the bearing sleeves are left in them and they are mounted as illustrated in the drawing at the right. Long carriage bolts secured at right angles. to the belt, leaving one-half inch clear¬ ance, will do nicely for mounting pins. A large wash¬ er on each end of the sleeve will retain the bearing and permit free turning when the guide is bolted to the support. These guides should be set up near pulleys on which there is danger of slippage. An¬ other point is midway between two pulleys spaced an unusually long distance apart, where the belt wobbles considerably. — Wallace H. McClay. 90

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Novel Uses for Pipe Odds and Ends the lawn through small pinholes in the pipe. UNUSED and rusting pieces of pipe lying The chief advantage of this sprinkler is around in your basement workshop or that it can be laid snake-fashion around on garage can be pressed into service as use- the lawn. A 2-in. pipe sliced in half with a ful members of society. A sturdy hedge hack saw makes a surprisingly sturdy fence to shut in cattle and keep out tres- bumper. The accompanying drawing gives passers can be made out of miscellaneous all necessary details. The pipe should be lengths of inch pipe connected by 90 de- mounted on the car frame with %-in. strap gree ells, forming a saw-tooth fence as illus- iron. Note that the ends are bent to take trated above. away the sharp edges. — Weston Farmer. Imitation Candles Won’t Melt in Hot Weather HOUSEWIVES who have candles on the buffet or dining table as decorative center pieces can eliminate one ■H table as decorative center pieces can eliminate one hot weather worry by making substitute tapers of wood as illustrated in the drawing at the right. It is a simple matter to turn a birch candle in wood according to the calipered dimensions of the original. A piece of wool fluff at the tip will make it look authentic, and real candle wax can be dripped around the top to complete the _ _ . _ realism. — Dexter Masson. Wagon Saves on Ice HERE’S a little chaser built from workshop -H built from workshop odds and ends that proves ideal for transporting ice home from cash and carry ice houses. The body is merely a portion of an old soap box, while the wheels are the front and rear sections of a roller skate. A 1x2 about 4 ft. long does duty as a handle. A cake of ice fits snugly in the box and can be carried home with a minimum of loss from melting. — George Norberg. Sep 91

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Helpful Kinks for Handymen Iron Speeds Soldering Seams on Large Work can save a lot of time by employing an elec¬ tric flat iron as illustrated in the accompany¬ ing drawing. The heart of the stunt is a folded metal strip attached lengthwise to the bottom of the iron which glides down the seam applying the solder as fast as you can feed it. How to bend the strip is shown at the left. In use, the flat iron is plugged into a convenient lamp socket. When running the iron along a seam, the solder is fed in under the strip at either end of the iron. The heated copper strip melts the solder and at the same time spreads it evenly on the seam, • doing a perfect job in a jiffy. Of course, the metal should be prepared for soldering in the usual manner. — A. H. Waychoff. Guard Keeps Walkers Off Lawn Corner IF YOU live on a corner and have an unfenced lawn you no doubt object strenuously to having people cut across your yard to save a few steps. Here’s how to put a stop to this short-cutting. First lay hands on a piece of screening about the size specified in the accompanying drawing. Then drive three stakes, one in the corner, and two others along the sides, as illustrated. This done, stretch the wire between the stakes and nail it in place. Finally apply a coat of bright green paint, so that no one can miss seeing the guard. If you have no screening available you A Radiator Cap Camera Tripod EMPLOYING this clever stunt, motorists who like to take scenic photos en route can leave their tripods at home. On an auxiliary radiator cap is mounted the shank of half of a ball and socket joint, available from any auto shop. The upper section of the joint attaches to a platform on which the camera is seated for taking pictures. When taking a picture simply change to this radia¬ tor cap. — L. B. Robbins. Protect Slopes Against Erosion AN ingenious stunt employed by Califor¬ nia highway engineers to prevent ero¬ sion of banks and hills can be adapted to use on your own lawn. With this method, illustrated in the -drawing at the left, any slope over 30 degrees can be thoroughly protected against the heaviest rains. An inch or two of straw or light brush mixed with soil is laid over the slope and chicken wire is anchored over it. Next a thin layer of sifted soil is spread on the wire and sifted. Continuous downpours won’t phase this type of a guard in the least and you’ll be assured of finding your front yard just where you left it, after a storm. — Hi Sibley. 'yp.i: 92

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J- down a few rules for giving first aid to trees that may be followed by anyone. Lightning and wind usually tear off a limb or split a crotch. If a limb has been torn off near the trunk the jagged edges should be sawed off and the wood shaped with a sharp knife. Splintered wood may be chiseled away. The outline should be regu¬ lar and pointed at the top and bottom to prevent dying back of the bark cut off by the sap flow. The wound should finally be smoothed and painted with asphalt or Bordeaux paint. Asphalt paint may be made by dissolving asphalt in pure oil of turpentine. Three cuts are necessary to remove a large limb close to the trunk. First cut up once underneath the limb about a foot from the trunk, sawing in till the weight binds the saw. Then make a downward cut two inches farther out. When the limb falls it will not split the trunk or rip off the bark. The third cut is then made as close to the trunk as is convenient. The wound should be painted when finished. In the case of a split crotch, draw the branches together with a block and tackle and hold the injured members in place by passing bolts through the tree. If the strain is too great to be held by the bolts, as illustrated. When job is finished, holes may be filled with cement and padded over. When working on a thin-barked tree, rub¬ ber soled shoes should be worn. Handy Method for Pouring Babbitt Bearings BABBITT bearings when poured in the usual way are very tight and hard to break loose. They must be turned in or burnished to a fit. To save all this trouble, cosmolene the shaft and wipe it free of excess oil. A piece of tissue paper is then patted down around the shaft on this layer of thin grease, and joined by close edges. This tissue paper will be charred and will fall out after babbitt has _ _ _ Fireproof Vault Built in Mantelpiece WHY worry about those insurance policies, deeds and valuable papers at home when you can de¬ posit them in a vault built into your fireplace. Here’s how it’s done. Remove several bricks at a place where you know you will not enter a flue passage. Then on the inside put a couple of flat bars to receive a small concrete box which you can cast in your workshop. The bricks taken out are now to be cemented together, forming a door. All around the outside of the door cement asbestos sheets the thick¬ ness of the old mortar joints. — B. H. Thomas. B°* I BRICK CEMENTED ON FRONT 93

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(general c Purpose TRAILER ;avy ~ oses y "7* Sturdy as an oak, the chassis on this heavy duty trailer is adaptable {or all purposes from motor camping to freight hauling. — m DAIRYMEN, truck gardeners, orchardists, motorcampers — anyone with any haul¬ ing to do — will find in this trailer chassis just the thing to fill a long-felt need for extra freight space. With auto wrecking yards teeming with axles, springs and wheels which can be bought for a song, it this type of axle. is as inexpensive a job as you could want. Two outstanding features are to be found in this trailer: it is underslung, and it has brakes. Thus there is little danger of a spill when carrying a heavy load, and thus also the trailer can always be kept under com¬ plete control. On a slippery hill, the brakes, needless to say, will save you from many serious mishaps. It would be impossible in a single article to give details of body design to meet all requirements, so this article centers on the essential chassis construction, leaving the style of body optional with the builder. Instead of using a discarded front axle assembly as the basic unit, the underslung trailer is built up on a rear axle assembly of the full-floating type. Figure 6 illustrates The full-flc - * - S e p t e ib e r ll-floating type axle 95

Page 96

Comfortable "House” May be Built on This Chassis for Camping Trips Rear elevation of the house trailer, 1 _ .. quired by law, so plan on built-in lights o models is particularly recommended for the underslung trailer chassis. Remodel the axle as illustrated in Fig. 10. outer housing can be cut away with a ■.saw and be replaced with a suitable th of pipe. And the long shaft can be ;d through the axle tubing. Then the assembly can be towed to a welding shop : — - - - - - — — for welding. b"tefo if winhoithe ,ra,Ifrncim arranged most conveniently jf brakes are to be used on the trailer — tied with plenty room^or cooking^eating^and so forth! and they should - then the axle housing . ’ , must be made rigid to the spring saddles. The saddle can be made rigid by clamping the cap tightly and using cap-screws, or by welding the entire saddle to housing. In welding, care must be taken not to draw the temper from the spring leaves. It is best to find the exact location of the spring saddle with reference to the brake band, and then remove the spring before welding. 96 Modern Mechanix and s one from which the driving axles can be withdrawn without disturbing the wheel bearings. They can be acquired at any auto wrecking yard for a dollar or two. The only parts of the rear axle assembly for which there is a “used parts” demand are the driving axles and differential parts. The rear axle assembly from early Cadillac

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Chassis Rides on Remodeled Rear Axle Assembly Taken From Cadillac >f large-size blueprints for this heavy- auiy trailer are available from Modern Mechanic and Inventions for #1.00. These plans, ideal for use in the workshop, are taken from the *' ‘ and show every detail of construction, naares: Modern Meehanix and Inventions Blueprint Dept. 529 South 7th Street, Minneapolis, Minn. The emergency brake shoes serve no pur¬ pose on the trailer, so they can be removed from the brake drums. After the axle has been prepared it is a comparatively simple matter to build the chassis. Figs. 2, 3, 5, and 8 show re¬ spectively the plan, side and front eleva¬ tion, and the notations indicate the material used. Except for variations in length, the construction shown will serve for almost any body design. Inv Sept The most important part of the chassis is the chassis sills. (See Fig. 3.) These are built up with a maple (or oak) center core 3" wide and faced on each side with 3/16"x3" steel bar. The overall width of the finished sill is the same as the springs of the trailer — probably 2%" or 2 W. The sketch shows the hanger built up with 3" blocks of maple, but one 9" block would serve as well. (Continued on page 126) 97

Page 98

Starter Motor Makes Outboard Engine — Ideal for Fishing Gas motor of Johnson outboard is removed and in its placets installed starter motor operating off storage batter- Magazines Make Target Backstop BASEMENT targets using wood to stop the bullets are often found quite unsatisfac¬ tory because the area around the bull’s eye soon splinters and permits the bullets to fly through the other side, damaging anything that happens to be in their path. There’s a remedy for this dangerous situation, how¬ ever. One exper¬ imenter found that old maga¬ zines, tied togeth¬ er as illustrated in the accomp¬ anying photo, make an unyield¬ ing back-stop. About four maga¬ zines of normal thickness are needed and they are held together with wire. The magazines should be of the small size, like the Atlantic Monthly, Mod¬ ern Mechanix re bound rightly with AND INVENTIONS, ike target backstop. Or SCRIBNERS. IDEAL for trolling is the ingenious electric outboard motor devised by a Portland, Oregon, workshop fan. As may be seen in the accompanying photo, the lower part of the contrivance was taken from a Johnson outboard motor, and in the upper part^the place where the gas engine ought to be — was installed an old auto starter motor. Two six-volt storage batteries furnish power. They are good for about eighteen hours of cruising on one charge. The en¬ gine turns over without the slightest noise, and is thus ideal for fishing. Weight, in¬ cidentally, is only 21 pounds. Substitute for Stencil Brushes PAINT shops in small towns rarely carry stencil equipment, especially the small brushes that are used for this purpose. But don’t be downhearted. Your local drug store or hardware store carries a cheap brush that will serve excellently on a sten¬ cil job. This brush is the kind used in black¬ ing shoes. Cut off the bristles about three- quarters of an inch from the end, making all the hairs level. Thus shorn, the brush will work nicely on a stencil. Simple Klaxon Roars Like Lion SIMPLE, yet powerful as the roar of an infuriated lion, this easily-built Klaxon will startle you with its suddenly-developed volume. Here’s how to build it. First a fine toothed gear is set-screwed On the shaft of a fractional horse-power motor. Then a small piece of hard steel ground to a dull edge is fastened to the center of the bottom of a large tin can, as illustrated above. The device is finished by building a simple framework about the motor and of suitable height. The revolving gear teeth scraping against the steel point on the can will cause the bottom of the can to vibrate violently. A close estimate of the weight of ice can be reached by multiplying the length by the breadth by the thickness of the block, and dividing the product by 30. This method will easily detect short weight. Modern Mechanix and 98

Page 99

‘Photo dMagic and Profit from Speed Film FEATS of photography long considered impossible have now been placed within the reach of everybody by the introduction of high-speed film coming in rolls and packs. When used in conjunction with the high-speed lenses that are now available on low-priced cameras, particularly the miniature type, the new film, known as su¬ persensitive panchromatic or other similar names, will surprise even the seasoned pro¬ fessional. For instance, you can shoot pictures of your friends at a banquet table or party, if the room is at all well-lighted. You can snap “candid” pictures of celebrities on trains. You can procure good pictures of store windows which are of particular in¬ terest to you. You may even make some extra money photographing store windows and selling the pictures to trade journals, providing, of course, that there is something sufficient¬ ly unusual about the window. Candid camera shots of well-known persons in restaurants or other informal settings sometimes can be sold to the newspapers, restaurant owner or even the subjects themselves. If you have a camera with a lens whose speed is rated at f:3.5, and a shutter hav¬ ing a 1/10 second setting, you can photo¬ graph almost anything as well lighted as a store window, theatre stage, railway coach or dining room, providing you use the new panchromatic film. Even if your camera lens is no faster than f :4.5; or even f:6.3, you can obtain unusual pictures simply by giving a little longer exposure. By using a color filter you can procure good cloud effects — when there are clouds. It is best for photographing distant objects. Globe Blows Up Like Balloon A GLOBE that stands almost two feet high when set up can be completely taken down in a few seconds and made into a package that will fit the pocket. The globe itself is a perfectly round balloon made of a special rubberized Japanese silk which will not leak air. No rubber is visible on the globe. Its sur¬ face is fine silk on which the continents and oceans are accurately printed in delicate colors. A small metal “Hour Circle” placed at the North Pole makes it possible to figure the exact time or the differences in time at orbetween anyplaceorplaces in the world. Made of special rubberized Japanese silk, this globe can be quickly inflated and set up. All terrestrial features are marked distinctly. Can be carried in pocket when deflated. Inventions for September 99

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TLANS for a FIDGET TV/fY SALUTE to the web footed members itlof the Hangar Gang! This is Eddie Fitzgerald talking, and may I introduce myself again as the chap who made Andy’s column some little time ago with a picture of my Midget? Remember the letter where I said I’d answer all inquiries concerning the little go-devil? That was some time ago, and I wish now I hadn’t volunteered to cough up the info, because I have since moved a couple of times from my former home in New York City, and letters persist in dogging me to my new address. So here’s the dope for all: This little cart was built for Jiext to noth¬ ing in the way of materials, and constructed according to instructions Fm shooting you in a few minutes. She will do nicely as a racer in the new class “M” or Midget class, and will skedaddle along at about 25 miles an hour with one of the small 2-cylinder opposed 2 h.p. Johnsons, or equivalent. Outboard Motors Corporation of Milwau¬ kee, Wisconsin, or the Johnson Motor Com¬ pany, of Waukegan, Illinois, or the Caille Motor Co., of Detroit, Michigan, all make 100 Modern M echanix and

Page 101

Outboard ct?£YDRO Edw. Fitzgerald TRANSOM OF engines which fit the class M specifications, and if you will write these firms you can compare the merits and prices of the motors if you do not have one already. I got up a mimeographed sheet that I sent to a whole slough of fellows who asked me about my little job, and here is the sheet, word for word: Good tools, plenty of space and at least some knowledge of carpentry is essential to build this little hydro. Tools should in¬ clude: Hand or breast drill, small plane, ratchet screw driver (unless you like blisters) and, of course, hammer and saw, a good rule; a square will also be very handy. 2 pieces of white pine, 8 ft. x 8 in. For (Continued on page 128 ) The outboard and inboard construction profiles of Eddie’s Midget. You will note there is no step. In such a short boat, unless used for extreme racing, there is little to be gained by the use of a step. Framed thus, boat is easier to build. Inventions lor September 101

Page 102

Learn Physics from (Mystifying <<5RICKS 102 Modern M e c hani x and

Page 103

Page 104

T enguin Seaplane Skims ‘Water 15 m.p.h. lt/IR. TONY PORTER, who lives at Went- ■1*1 worth, England, is fortunate in having a dad who goes in for the same kind of thing Master Tony does. Consequently Mas¬ ter Tony was recently presented with a midget seaplane having a twin opposed motorcycle engine to wind its prop around, real floats, real fuselage and everything. Would you like to build a simplified ver¬ sion? Modern Mechanix and Inventions designers have sketched out the propor¬ tions of this little water scooter, and pre¬ sent herewith plans for a non-flying plane which can accommodate any youngster weighing less than 100 lbs. The floats are 10 ft. long and a foot and two inches square. The outboard profile is like that of the drawing. The %" spruce longerons, braces and cross pieces of the framework are glued with casein glue and fastened with brass screws. Then eighth-inch Haskelite is nailed on with escutcheon pins along the edge. The edges and the seams must be treated with marine glue. The floats are joined by two four-foot lengths of %" seamless steel tubing held in place by U-bolts as shown in the sketch. The control elements may be constructed in any conventional manner, possibly the best being out of %"x%" spruce flat strips riveted with small copper rivets. The covering is done in the orthodox manner, using AA muslin, obtainable at any department store. Acetate dope is brushed on. After the third or fourth coat t can be applied and the component i, wings and surfaces, mount- paint parts, ed oi Any motor of about a half to one power, such as an old washing machii tor or a power head from an outboa gine, can be used to drive the propel ird“S: filer. 104 Modern Mechanix and

Page 105

T'lgvel Scientific ‘•S’RICKS ‘Wit h 'Watches Inventions lor September 105

Page 106

c&al <e thrilling Underwater r)u get all the keen thrills of deep-sea diving and underwater cruising in this one-man submarine. Towed by a motor- boat, the novel craft will take you down to a depth of at least 30 feet, where you can explore the river or lake bed. Through a special conning tower you can watch the fish as you dart among them, the while maneuvering about like a real submarine. Construction of the sub-sea boat calls for the use of either a welding torch or a rivet¬ ing outfit, the former being preferred, as it makes the craft completely water-tight. Dimensions herewith are for welding. Measurements will have to be increased for overlapping if the members are riveted. One-eighth inch flange steel or three- sixteenths inch tank steel is used through¬ out. Complete dimensions for the body are given in the drawing at the top of the page. The sheet should be bent into a cylinder 19 in. in diameter and welded. For the accommodation of the skipper, and also for internal bracing, an interior deck is constructed. On this the navigator lies, stomach down, and hands on the con- M o detn M e c hani x and 106

Page 107

Cruise in 0NE-e5¥AN 5UB Control rods pass into hull through the 1-in. pipes, which are soldered to the metal as seen above. Skipper inspects Eye bolts are secured over hooks to tighten down tower. trol lever, as demonstrated in an accompa¬ nying drawing. The deck end pieces are welded in place, as is the deck itself. All other necessary dimensions are given in the accompanying drawing. The con¬ struction of the conning tower lid, how¬ ever, calls for comment. Note that the “lid” is equipped with a strip of rubber which renders the sub air-tight when the conning tower is tightened down. Take particular pains here to get a good, water-tight fit. A point that has to be determined sepa¬ rately for each individual case is that of buoyancy. This depends partly on the weight of the materials, and partly on that of the operator. The floating buoyancy may be lowered by boring numerous holes in the bottom of the hull below the interior deck, the effect of these being to give the craft a water ballast. The submerged buoyancy may be low¬ ered considerably by boring holes in the (Continued on page 133 )

Page 108

Automatic Relay Keeps the AMATEURS and broadcast listeners using battery operated receivers will find this trickle charger relay a great convenience. When you’re through operating it auto¬ matically cuts in your trickle charger and Radio Battery Fully Charged thus always keeps your battery up to full charge. First procure a pair of heavy duty mag¬ nets from an old door bell and mount them on a baseboard as illustrated in the accom¬ panying drawing. Remove the bell arma¬ ture and mounting and reinstall them over the magnets so the armature clears them about Yi in. Wire the spring pivot to a binding post as illustrated. Now make your two contact posts A and B as illustrated. The contact screws should have flat pointed ends. Screw A makes per¬ manent contact with the armature, while screw B makes contact only when the arma¬ ture is pulled down. Wire up ihe relay according to the cir¬ cuit. Operation is as follows: Switch on the receiver and the magnets are energized, pulling the armature down to B. This dis¬ connects the trickle charger and completes the AG circuit to the eliminator. When the receiver is switched off the eliminator is disconnected and the charger cut into the circuit, thus putting battery on charge. If B batteries are used you won’t need the eliminator circuit. It will be advisable to insert a fuse in the line to the 110-volt A. C. house current. Simple Volume Control Permits You to Adjust Receiver From Easy Chair MANY modern broadcast receivers per¬ mit listeners to tune in at the chair while the speaker is over in a convenient corner, so it will not be a bad stunt for us to consider making a remote volume con¬ trol for the old set. Receivers using a triode (three element) tube as a final audio call for one method where an output transformer is used to the speaker. With no output transformer, a different method is used. Sets with an output transformer should have a variable resistor across the sec¬ ondary as a volume control, as illustrated in circuit A. This can be housed in a neat little box on the table beside the chair and connected across the transformer second¬ ary as shown. Use No. 18 twisted lampcord laid under the rug and you will have a handy and useful arrangement. For a triode tube use 50,000 ohms and for a pentode tube use 25,000 ohms. For sets without output transformers the resistance is merely connected in series with one side of the speaker cord as shown in circuit B. The control cabinet should be padded to prevent scratching of the table or stand. 108

Page 109

Key for Buzzer Practice Set Made From Old Phone Jack Mount the old phone jack on a baseboard as illustrated here. Saw off lower part which holds the opening for plug. Home-made Mike From Head Set A MINIATURE “mike” which gives sur¬ prisingly efficient service can be con¬ structed at little cost from an ear piece taken from an old set of head-phones. This can be mounted in any convenient or artis¬ tic way, as illustrated below. In hooking up the microphone for use with your radio attach one of the wires to the grid prong of the detector tube and ground the other. The regular ground for the set can be used for this. All the connec¬ tions should be fastened tightly or soldered to reduce interference noises. This home-made “mike” will give very satisfactory results, and will prove very amusing and entertaining. A cut-out switch installed on the mounting base enables the “announcer” to turn the “mike” on or off for his home program. 'Mike made from head phones may be mounted as shown. Increasing Resistance of Carbon HERE’S a simple way to increase the re¬ sistance of a carbon resistor in an emergency. With a wide file gently file down a flat place in the carbon, testing the resistance every three or four strokes with an ohmmeter. The more carbon that is removed, the higher the resis¬ tance becomes. A few strokes may be sufficient. by filing oi AN OLD phone jack mounted on a base¬ board as illustrated at the left makes an excellent key for use with a buzzer practice set. A poker chip or large button glued or bolted to the tip will do duty as a knob. Careful adjustment of the contacts will give you a nice smooth touch and teach you how to handle a real key when you go on the Two Way Grid Leak for SW Work II7ITH the arrangement shown here you may be able to boost efficiency of your grid circuit. From the grid side of the leak install a 0-5 megohm variable resistor, bringing it down to the grid return. Ry removing the leak across the condenser you get the effect of a grid return leak, or by closing the variable leak to 0 you get the effect of the regular leak and condenser combination. You II _ can also use both | — 1| - 1 together. — Note that the re¬ maining side of the 0-5 megohm variable resistor hooks to the nega¬ tive side of the fil¬ ament. Make sure that this connec¬ tion is correct be¬ fore final test. Replacing 245 Tubes with Pentodes ARE you getting a bit tired of the old set using a 245 audio tube? For more vol¬ ume and better tone you can replace it with a 247 pentode with but a few changes. Note the two diagrams below. Use the same filament circuit, but instead of a 1500 ohm grid bias resistor use one of 500 ohms, and substitute a .25 fixed condenser for the 1 mfd used with the 245. If you use a socket adapter for the 247 buy one with an iron core choke contained in its base. Otherwise you will need one of about 15 henries to shunt across between plate and screen. The screen, by the way, takes the same voltage as the plate, namely 250. Inventions for September 109

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trailer cAttachment for All Makes of Cars Repair Honeycomb Radiator Leak THE simplest and most effective way to repair a leak in a honeycomb radiator is first to remove the radiator from the car and clean the surface at and around the leak. Next coat the cleaned surface with soldering flux, then whitewash the radia¬ tor around the leak, but not over the part which has been cleaned. Place the radiator in a slant¬ ing position, and slowlypour solder over the cleaned surface. The solder will adhere to this surface, closing the leak, but due to the coating of white¬ wash it will not adhere to the sur¬ rounding surface. This method is generally consid¬ ered better than using a soldering iron as it prevents accidental over¬ heating. AUTOMOBILES fall into three styles of rear end design, each of which can be equipped for trailer towing by one of the methods shown in accompanying drawings. The Ford Model-T is easy to adapt. The towing yoke is made by bending a piece of ]/4 in. by 1 % in. strap iron and half-winding it to fit flat under the rear spring shackle bolts. They are drilled for the shackle bolts, and the hook is bolted down in place of the shackle plates. The hook is then in¬ serted into the two front holes of the frame, and the old valve springs are put on and secured in place by double lock nuts. For cars having no place but the bolt on the rear tire carrier, a very effective and simple hook can be made from an old ball and socket rigging, such as from the steering gear of an old car or the wishbone radius rod of an old Model-T Ford. Cars having bumperettes may be adapted as illustrated in drawing in the upper right hand corner. The 2”x2'' white oak bar is held in place by a pair of back blocks, anchored firmly with carriage bolts. Any kind of towing toggle may be employed. All these attachments have been used on loads up to 1600 lbs. on a 4-wheeled trailer. Dispenser for Soldering Paste A HIGHLY con¬ venient con¬ tainer of solder¬ ing paste may be made by cutting off the end of an old tooth paste tube and filling the latter with the paste. The bottom of the tube is sim¬ ply folded over af¬ ter the tube has been filled. Squeez- Squeezing .he toothpaste tube ing lays 3 line of applies solder paste to metal. P3Ste. 110 Modern M e c han i x and

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TeSt What You Buy to Qet dY[ oney’s Worth

Page 112

It’s Easy to Make Photostatic Copies With Your Camera VERY often it is desired to make a copy of some document or other printed or typed sheet. If you have no regular photo¬ stat camera the only other means at your disposal will be to photograph the sheet or page with a process plate or film, and then print it on ordinary photo printing paper. This is a long and relatively expen¬ sive procedure. All that is necessary to convert your cut film camera into a photostat apparatus is a prism, which is placed over the lens to reverse the image. For a small camera the prism from an old pair of binoculars will serve the purpose. Make a tin hood to fit over the prism, leav¬ ing open the two faces which meet at a 90° angle. Paint the inside of this black or paste black paper in it, and fit the prism inside. Now you can either make a tin ring to fit over the lens, or, if you happen to have an old ray filter, use the metal ring. Solder the hood onto the ring as shown in the photo. With this small attachment you can in¬ stantly convert your camera into a photo¬ stating apparatus. Simply load the cut film holder with bromide paper. Set the cam¬ era level and place the sheet to be copied below as shown in the illustration. You will have to determine by experiment how long the exposure should be. The picture or document to be copied should be thumb-tacked to a sheet of ply¬ wood or other smooth board, making sure all “hills’ are removed. top. Below is seen illustrated method of focussing. Photoflood Light for Indoors EIGHT photoflood globes grouped inside an octagonal frame make this lamp the equal of an arc light for the home photog¬ rapher, permitting snapshots of 1/65 sec¬ ond in dark room, with lens opening F 4.5. The frame pieces are held together with splines glued in one end only, and four screws from a plywood back. They can be taken apart in a minute, to use the lamps strung out singly or in groups. When wir¬ ing, therefore, leave a little slack between sockets, for this purpose. Cut the reflector gores from cardboard, join them with strips of cloth glued on, and glue the assembly inside the back. After fireproofing with a coat of waterglass, finish with two coats of aluminum paint, and mount the reflector on a bracket with a bolt to slide in the standard slot. With a lens stop of F 7.7 (U. S. 4), give these exposures for par-speed film: Lamp at 3 ft. from subject, 1/10 second; 4 ft., 1/5; 5 ft., 2/5; 6 ft., 3/5; 7 ft., 1; 8 ft., 1 3/5. If the room is fairly light, shorten expo¬ sures by one-third. 112

Page 113

Ordinary ‘rRgdioc£>ube Makes Electric Eye THANKS to the intensive research of Mr. W. P. Koechel, of Owensboro, Kentucky, a surprising photo-electric effect has been discovered in ordinary radio vacuum tubes. To electrical experimenters this will be good news, because it means that photo electric cells can be devised from inexpen¬ sive radio tubes. It has been found that the 210, the 245 and the 250 tubes are photo-electric to a marked degree, and that the light response is sufficient to trip a cheap relay. Tubes which give the best results are those having open or clear tops so that light from external sources may reach the grid. It is essential also that the grid prong be cut off as illustrated above. A circuit is given at the top of the page. The filament voltage, you will notice, is regulated by a power rheostat in the sec¬ ondary of the transformer circuit. The ex¬ perimenter will have to discover the best filament voltage by tests. The relays used in connection with these new photo-electric cells should be capable of operating on a range between 1 to 10 milliamperes. Modern Mechanix and In¬ ventions editors will be glad to give you the address of manufacturers of relays. When operating the tube, remember that the more light that reaches the grid of the tube, the greater will be the current output. Therefore it is advisable that the tube be installed in such a position that the beam strikes the top head-on, as illustrated in an accompanying photo. The vacuum tubes will be found unduly sensitive to body capacity, so it will be necessary to cover the tube with a metal shield, which is grounded to the negative filament. The top of the shield is left open. nnnnnnnn Tobe operated ^ _ y 1 10 VOLTS t Circuit for electric eye. Note that grid is left unconnected. Model Battleship from Hardware AN UNUSUAL battleship used in a win¬ dow display has attracted much atten¬ tion for a California hardware man. The entire ship is made of items in the store. Six-foot saws form the sides of the vessel, while fish reels, fish poles, shot gun shells, mouse traps and hose nozzles are used to form the deck fixtures and superstructure. Inventions tor September 113 Saws,

Page 114

MAKING JOUR ©WN Chemistry is always fascinating when your experiments bring practical results. This article describes a process used in making the line cuts used in illustrating how-to-build articles in this magazine and shows you just how you can make them yourself for your own printing. Experimenters who enjoy dabbling with chemistry and photography will find the making of zinc etchings — photo line-engravings— a pleasant and lucrative hobby. After some hours spent in master¬ ing the rudiments you can soon learn to make printing plates for your own letter¬ heads and hundreds of other things with the advantage that the designs are striking¬ ly original and different from matter set in type. If you have an aptitude for drawing, your sketches can be easily made into metal from which as many copies as you wish can be printed. If you are not artistically inclined, follow the method described below and you can make excellent drawings of any subject with the aid of your kodak. In making the plate shown in the illus¬ trations, a photograph of a girl was used. This was enlarged to 8x10 size. Line Photograph with India Ink Place the photograph on a flat surface and commence the drawing by going over the outline with a pen and India ink. You should have a fine pointed and a broad pointed pen at hand; the former for shad¬ ing in the delicate lines, the other for the more solid lines; and a pointed brush for filling in the completely black portions. After the figure is outlined, use the broad pen and do the dark portions. Where there are shadows, shade in the portion with fine lines drawn closely together. When the photograph is completely lined with the India ink, it is allowed to dry well and then immersed in a solution made by dissolving a negative reducing powder in a small quantity of water. The reducer will slowly eat away the silver of the photo¬ graph, leaving your drawing on a white background. This should be rinsed well and dried, when any portions you neglected can be touched up with a pen. Now make a negative of the drawing with your kodak. Give a normal exposure, and in developing the negative use a pinch of potassium bromide to keep the lines clear. It should be somewhat overdeveloped to acquire density. You now have a negative for printing on zinc, and the next step is to prepare the zinc. A piece of heavy sheet zinc is cut slightly larger than the negative, and one side thor- M oder n M e c ha nix and 114

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^mc ^TOHINGS^°K.B. MURRAY oughly polished with water and pumice powder until it acquires a silver brightness. It is then washed and polished with a dry, clean cloth. Beat up the white of one egg in a graduate and add to it two ounces of distilled water. In another ounce of the water dissolve ten grains of bichromate of ammonia; this solu¬ tion is stirred into the egg white solution. Add six drops of strong ammonia water. This makes a slow-acting sensitizer for the zinc plate. The coating should be done with yellow light for illumination. Flow a s over the brig ing it to drai time the s flat side of a tootl plus and hold th< heat, preferably g ing it at an angle so t tion will flow off, gent It will dry in a r the plate be 1 will bear. Place the i and the sensi Exposure to a s „ „ . an arc light, is necessary for about eis minutes; with daylight, from one to 1 minutes. low light and given a very thin coat of printer’s ink with a roller. Then place it in a tray of water and after a minute draw a wad of wet cotton over the surface. The background should come away, leaving the black inked lines of the drawing on the shining metal. If the entire coat of ink comes away, the exposure has been in¬ sufficient; if the background refuses to leave the plate, the exposure has been too long. In either case of wrong exposure, the plate can be repolished with pUmice and the ex¬ posure repeated after sensitizing. When you have the exposure right and the background and space between the lines of the drawing are clear, shake off the sur¬ plus water and dry the plate by blowing on it over a slight heat. Proceeding With the Etching When the plate is dry, it is dusted with a resin powder; ordinary resin can be used, or the resin known as Dragon’s Blood, which is a red powder. Brush off the sur¬ plus not adhering to the inked lines, and heat the plate until the resin melts and be¬ comes glossy. The back and sides of the plate are then coated with asphalt varnish. The etching solution consists of thirty ’ ane part strong nitric acid, I carefully. It is placed in ss tray; the plate dipped o the tray, where it should mms mm Inventions tor September 115

Page 116

Directions for Etching the Plate paipt?,: rest on the bottom, face up. Place a pencil mid¬ way underneath the tray so that it can be easily rocked, flowing the acid solution back and forth over the plate. The parts of the zinc not covered with resin or var¬ nish will dull and small bubbles of hydrogen form. These should be removed fre¬ quently with a flat brush, which also brushes away the oxide formed on the ex¬ posed zinc. Undercutting, or etching away of the finest lines, is caused by too strong an acid. Therefore the fine lines should be watched; if they commence to be etched away, the plate is removed from the tray, rinsed in pure water, and the fine lines retouched with a fine brush and the asphalt varnish. When the etching has proceeded to the depth equal to the thickness of a calling card, it is removed, washed and dried for re-powdering. The plate is held in a ver¬ tical position, resin powder flowed over it, and the excess removed with a soft brush held in a right-angle position to the plate. The edges of the etched portion will hold the resin. The plate is then heated to melt the latter. When cool, another side is treat¬ ed in the same manner, until all four sides of the etch, or “bite” as it is called, have been protected by the resin. Now return the plate to the acid bath, which may this time be strengthened by the addition of another ounce of pure nitric acid. Etching is continued with until the fine lines again show danger of being undercut. By this time the deptlr of the etching will be sufficient so that the lines of the draw¬ ing may be gone over with asphalt varnish, on a brush to entirely protect them from action by the acid. On returning the plate for further etching, the acid should be fur¬ ther strengthened so as to eat deeply into the background and broad spaces between the lines. When these broad spaces have been eaten away to half the thickness of the zinc, the operation is completed. The plate is washed with benzine to remove all varnish and resin, when it is ready for trimming and nailing to a block of wood that will bring it up to type height. If you do not have a small printing press available and do not wish to go to the ex¬ pense of having your cut printed, good re¬ productions can be had by the following method: The etching is placed on a solid surface and inked with regulation printer’s ink. The paper to be printed is placed face down on the etching. A block of wood cov¬ ered with several thicknesses of fairly soft fabric is placed on the paper and tapped with ~ mallet. This transfers the inked impression to the paper. Frequently plate and paper can be run through the rolls of a washing machine wringer, in which case the plate need not be mounted on wood. Use this method for print¬ ing linoleum blocks. ;£§,p: 116 M ix and

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Unique Qloiv Lamp Last ItOord in J^ovelty Modernistic and unique, the ^ glass, rod lamp AN INTERESTING lighting ornament for the table is a glow lamp that you can make from a few lengths of glass rod, some plywood, a candelabra socket and lamp, and a few other odds and ends. The lamp consists of a base for supporting the glass rods (Pyrex or towel) in an upright posi¬ tion, and for housing the miniature lamp which is placed directly beneath the lower ends of the rods. Rays from the filament are confined largely within the rods by internal reflec¬ tion, and illuminate any small bubbles or other imperfections in the glass. Ends of the rods glow in a weird manner. Designs ground or etched on the surface stand out strikingly. Group the rods together and tie them with cord or tape. Then cut, in top of the base, an opening conforming to the cross- sectional form of the group of rods. Slip the rods into place, invert the lamp, stuff cotton around the glass and into all spaces between rods, and pour plaster of Paris, mixed to a thin paste, around the rods. Let it set for an hour or two before moving the lamp. Then mount the socket so that the bulb, when screwed in place, is directly below the rods. Be sure that the rod ends are free of plaster. Data on the lamp illustrated are: Rods — three pieces % in. in diameter and 6%, 10 and 15% in. long respectively, of which 2 in. is imbedded in plaster. Socket — candelabra, brass, with a pull- chain switch that is not necessary. Lamp — - 5-watt, 115-volt G. E. Skid Chains for a Lawn Mower rr YOU have been assigned the job of keep¬ ing the lawn of your home mowed, you will no doubt agree that the skidding quali¬ ties of the lawn mower wheel prove quite trying at times. There’s a remedy for this difficulty, however, and that’s to equip the wheels with skid chains in the form of a rubber band from an old inner tube. These strips are applied as illustrated below and are secured firmly to the wheel with short lengths of wire, twisted underneath the rim. Inventions for September 117

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FOR twenty years, since the age of six. I’ve been building and sailing boats. My first was an eight-foot covered deck job with a wrap-around tarp over the cock¬ pit, and carried only ten feet of canvas. Since then I’ve sailed everything from a ten-foot Kayak to a forty-foot smack. At twelve I rode out a white squall on the St. Lawrence with eighty-foot of canvas over an eleven-foot canoe. In other words I like boating, and I like your mag be¬ cause you give us boat fans a break now and then. I’m very proud of my portable sailing rig, which I made last summer, and used very successfully. I got a big kick out of listening to the wisecracks of the hanger- ons at the liveries where I hired a row¬ boat. When I started to unload the tackle from the fliv, they started in wisecracking about “sailors.” Their laughter continued until I had clamped the six clamps, and cast off the stern line. But when they saw the boat dart away from the dock, and thread through the traffic, out into the open bay or lake, they didn’t laugh any more. If, for any reason, I came back to the wharves before “quitting time” I would receive any number of offers to take on a passenger or two. And the gobs who hired a boat and then spent the rest of the afternoon pulling their arms off rowing around — I’ve got my opinion of them, when, for ten bucks or twelve at the most, they could build a rig like mine, and sail away. Three Parts to Rig So gather ’round you Volga Boatmen, and give a listen. Here’s something new in the boating world. A portable sailing rig, which may be attached to any row¬ boat, even the kind you rent at a boat livery. It’s inexpensive, easy to operate, and safe. Best of all, it works. There are three separate parts to it. The first is the sail tackle. It consists of a tri¬ angular sail, two spars, a mast, and a bucketboard. The second is the leeboard arrangement, which takes the place of a centerboard. The leeboard proper is bolt¬ ed to a block, with a single kingbolt. The block in turn bolts to a sideboard, with four small bolts. Between the block and the leeboard proper is a ball-bearing fea- 118

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Sail Any Rented T^OWBOAT ture, found on no other leeboard I know of. The third item of your rig will be a steering block. This is merely an eight- inch length of two-inch pine, six inches wide, with an oarlock cup set in one side. Various bits of rope and line complete the tackle. The sail is triangular, as I said. It is twelve feet on the bottom edge, ten feet high, and twelve feet on the “hypotenuse.” It is hemmed on the two twelve-foot sides, and a grommet is placed in each of the three corners. The canvas should be doped to prevent mildew. It is cheaper in the long run to have an awning or tent company make up the sail itself, because they do a better job than you can hope to. Shaping the Cypress Spars The spars are cypress, twelve feet six inches long and an inch and a half square. Round the corners and edges with a plane, and then bore a half-inch hole about two inches from the end, on each one. Connect one end of the spars together with a loop of sashcord, so that they are loosely hinged together. The two ends should be about two inches apart when the loop is knotted. Lay the canvas llat on the ground, and punch holes, just back of the hem on the (Continued on page 132)

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Sleeping Bag Is Last Word in Comfort and Compactness Simple Stunt for Writing on Glass NY home mechanic who has a power- driven grinding-wheel may help his wife make a set of jelly glasses which, in place of carrying stickers for marking, may carry ordinary pencil marks made direct¬ ly on the glass. If the grinding wheel is a fine one and travels at high speed, the glass is simply brought in contact with it. The wheel will quickly grind all of the finish off, leaving the surface in such a roughened condition that it will take ordinary pencil marks. A graduated scale can also be marked on jars for measuring convenience. Only a narrow strip need be ground down side of glass. FOR him who follows the forest trails summer or winter, a sleeping bag is not only an added comfort but also a necessity. A practical camper with a lean purse can design a bag like the one illustrated which is not only light and compact but is adapt¬ able to any change in climate. Approximately 36 square feet of medium weight canvas, 30 sets of brass reinforcing ringlets, three or four snap-fasteners and a 21 ft. sash cord are all materials required. First lay out the 96 and 69 in. lengths of canvas, as illustrated in the accompanying drawing, then punch the holes according to instructions given. When the bag is folded along the vertical seam the holes on both sides must coincide. Snap fasteners are sewed on the bottom. Next sew an 8-in. strip, 69 in. long, to the underside of the right hand flap, 2 in. from the edge. This flap slips under the folded blankets to keep the bag cold-proof and the blankets clean. Knot a 21-ft. sash cord to the lower left ringlet of the bag so that one length is 9 ft. and the other 12 ft. Now you are ready to fold in blankets as told under photo. Nursery Alarm Scares Kidnappers THIS sure-fire burglar alarm, installed in the nursery at a cost of only a few cents, may prevent a tragic kidnapping. The drawings above illustrate construction and assembly. When a potential kidnapper enters the window he runs afoul the in¬ visible thread, thus tripping the lever and closing the circuit to the bell. Contact is made between the metal arm of the trap and a small copper plate on the baseboard to switch on the bell. Black thread should be strung across the window, since it is less visible than any other color. The end should have a hook so the thread can be taken down. 120 Mod Mechani

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Simple Kink Makes Clear Copy of Rough Surface Photos T INEN or rough surface photographs may be copied by a method that gives a per¬ fect photograph without showing lines or rough stipple surface. The procedure is as follows: Take two pieces of clear glass, one piece at least two inches longer than the other one. Put a small rubber hose around the edge and be¬ tween the glasses, as illustrated in the ac¬ companying photo. Fasten the glasses to¬ gether with clothes pins or paper clips. The hose may be bought at any ten cent store or a piece of old hose from a camera shutter will do as well. Fill the space between the glasses with a solution of one-half glycerine and one-half distilled water. Be certain that it is distilled water. Place the photo to be copied down in the solution and copy it. After copying, the glycerine is easily washed from the print and does not injure it in any way. Curve the loose ends of the hose around the edge of the longer glass and pour solution in a bottle where it may be kept for future use. Make Your Own Novel Chess Men /"''HESS players who find monotony in con- ventional sets may easily turn out chess men of their own unique and distinctive de¬ sign, to suit their individual fancy. First, the models must be cut from blocks of clay in fitting sizes for the six types of pieces. This done, the moulds are poured for each individual piece. This step em¬ ploys a small cardboard box, open at the top. Now paint the model and the inner walls of the box with some light liquid grease, then place the model in the center of the box, mix plaster, and pour it into the box until the model is wholly covered. After half an hour break the walls of the box away and cut open the block of plaster into two pieces, using an old razor blade. Remove the clay model, then brush the mould clean and grease it. With a rub¬ ber band, bind the half-moulds together. Finally to make the pieces, mix plaster and pour into the mould, tapping to elimi¬ nate bubbles. Let harden for half an hour, then open mould, remove men and clean. New Heels For Shoes From Two Pairs Old Heels OFTTIMES the home mechanic will find that he can equip an old pair of working shoes with new rubber heels by the simple expedient of salvaging the worn down heels of two pairs of discarded shoes. These salvaged heels should be split in half with a very sharp knife kept wet with water. This done, the heels are then tacked in place to form a heel of standard height, as illustrated in the accompanying photo. It will be found that this procedure will turn out a very neat and substantial job. Of course, if the old heels are worn too far down, they will be unsuitable. Leather heels may be built up by using the same procedure as above. Inventions for September 121

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Last ‘Word in Houses — the a ungalette ” OUT of the depression has come the need for compression. We have had to do with less and be happy about it. But long before the depression an army of home¬ makers, housewives, were asking for less space in houses and space more efficiently planned. In other words they wanted and ^till ask for more space in less room. That’s one reason wjiy the small kitchenette apartments came into favor. That’s why one room may now be planned to do the work of two and often three. But above all that’s the reason for these “bungalettes,” which are nothing but small compact houses in which every inch of space is often used to triple advantage. Two bungalettes illustrated here are typical of the newer types. Plan 5-Bv-27 is a low, snug-fitting house close to the ground, with its horizontal lines rather severely accented and in keeping with the general (Continued on page 127) Modern Me chanix and 122

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123

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Native Scenes on African Stamps rpHE stamps of many primitive countries X are marked by peculiarities which make them highly interesting, particularly to people in modernized areas of the world. On the Bel¬ gian Congo stamp you get a fasci- n a t i n g glimpse of life in the Af¬ rican bush, while on the New Zealand stamp you are shown the abori¬ gines at their favorite pas¬ time. Africa is fruitful in such stamps, and is thus a favorite hunting ground for collectors. Strong Agitation for U. S. 1 5c Piece WITH inflation looming large on the economic horizon, numismatic fans will be interested to learn that strong agi¬ tation is afoot for a United States silver 15 cent piece. Reason : much of the nation’s business is done under the 25c bracket. At present there is no method of adjusting 8%, 12%, 17% or other fractional percentages in price rises among cigarette makers, bread makers, slot machine operators, newsstand and movie operators without resorting to enormously increased, highly cumbersome penny-method of change making. In addi- 100% 200% 300% 124 tion, economists point out that one coin is easier to get for an item than two coins — a pertinent factor. The present nickel, dime and quarter coinage represents a 200% and 500% in¬ crease over the nickel in coin denomina¬ tions. A 100, 200 and 300% coinage would stimulate trade in many lines besides the ten-cent-store and slot machine industries. It is interesting to conjecture what the new articles brought into industry by such a coin would be like. At present the great variety of ten cent store items is limited in number by the nickel and the dime. A fifteen cent piece might under the prevail¬ ing scale of prices be responsible for ser¬ viceable cheap socks and articles of cloth¬ ing not now carried by chain stores because of the too-great price spread. 100% 200% ADLETS FOR HOBBYISTS STAMPS! 100 diff COLONIAL Colle Tools, Anything. zu.c selections. Particulars. FREE Gorgeous packet including Spanish airset, trial Royal^Stampco,’ BoxP56°M^ fSSth^PalaTenarcfuL ^ HANDY index to stamps (“The Stamp Finder”), illustr booklet on Stamp Collecting, and stamp collector's cal (listing “Everything for the Stamp elector”), & C00V.?rD^pt.m4S” for 5c post Dept, M, I s collector! a,' Canady15 COINS, California gold quarter size 27c; $54 size, 53c. 3c piece and coin catalogue, 10c. 200 different stamps and stamp catalogue, 10c. Norman Shultz, Salt Lake, Utah,

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HANDY MAN’S HOME MANUAL On Sale at All Newsstands for 50 Cents "Heavy Duty” Underslung Trailer (Continued from page 97) Cross-rails of lV2"xi" hardwood are amply strong for most trailers, but if heavy live-stock are to be carried it is better to increase the size to 2"x4". We will now take up the brake proposition. Figs. 4, 7 and 9 illustrate the theoretical working. Through a cock on the steering column, the vacuum created in the intake manifold when the motor is idling is communicated to two 3" cylin¬ ders. The pistons are literally “sucked” into the cylinders, and the brake bands are tightened by a rod leading to the brake arms. A 1/64" hole is drilled in each piston-head so that the vacuum is relieved when the cock is closed at the steering column. Figs. 7 and 15 show how and where the cylin¬ ders are mounted on the trailer chassis. The cylin¬ ders can he made from a capped length of 3" pipe accurately machined inside. Any 3” pistons from an auto wrecking yard will serve. Of course, they must be fitted with good piston rings. If one can obtain a pair of discarded cylinders from a two-cycle type motor, these will serve without any remodeling. If the ports restrict the length of the piston stroke, they can be filled in with any iron cement. Detail explanation of the guards over the tires and over the axle is not necessary. Instead of a metal housing over the axle, an inverted wooden trough can be used. So much for the trailer chassis. A number of body designs and purposes to which this trailer can be put are shown in illustrations. Improve Accuracy at Bait Casting / Continued from page 80) thumb on the reel to prevent the line from run¬ ning out. Note that the rod is not brought back, over the shoulder, but only a little past the per¬ pendicular in starting to cast. When the cast is finished, the rod will be slightly above the hori¬ zontal. Hence in casting the rod play is con¬ fined within a quarter of an imaginary circle. If the reel is not an anti-backlash model, the spool will have to be thumbed to prevent it from revolving faster than the line runs out, re¬ sulting in a backlash. If the reel has an anti¬ backlash feature, turn the adjusting nut until the weight will slowly pull the line out. In bringing the rod back for the start of the cast, the thumb must be held on the reel spool to prevent the weight from pulling the line out prematurely. In making the forward cast, the rod is whipped down to horizontal and during this motion the spool is released. It is difficult to tell the exact time to release the spool. That comes naturally after sighting at the target, and practicing a few times. If the spool is released too soon, the weight will likely over-shoot the target, or describe an unnecessary high arc, whereas if the thumb is held on too long the weight will probably strike the ground close to one’s feet. The next delicate timing is to replace the thumb on the reel, and increase the pressure 126

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th^line mustier ^nd fa° rl ^eveill the spool. An unevenly wound line will cause back¬ lash. With practice one may learn to guide the line with the left forefinger and thumb, holding the rod in the left hand at the same time and Making Movies Beneath the Sea (Continued from page 65) the'switch th^f rtedthe ^amera^crtor turmT and sit with my eye tight against the finder, hop- S'Bssks Igallfstll I have seen many sharks, hut never have seen £ K£rSS«*25 siiifsss ris z,oi£r°“ The 1933 FLYING MANUAL is now ready tor YOU! Ajswsa SSfSHIS^Ii l£H” imfiER Thi* 'tl’lSoNTX' loMaKeMON 127

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Wonderful Invention! Brings the convenience of city gas to the rural home. Takes the place of gas in metro¬ politan areas with tremendous saving in cost. A better, cheaper and more efficient heating medium that all should have. There is a burner for every use. Thirty types and sizes. BIG PROFITS for Agents and Dealers No More | coal, wood or ! other fuels to I carry. No soot, smoke, ashes or dirt. Just clean heat. THIS MODERN AGE DEMANDS a heating service that neither includes the back breaking labor of the old fuels, coal and wood, nor the expense of gas and electri¬ city, yet having the highest possible efficiency. Oil Heat Is the Answer Agents and dealers write now for descriptive catalog and money making plan. Your dis¬ trict may still be open. PRESTO GAS MANUFACTURING CO. 2439-49 N. Western Ave. Chicago, Ill. Seattle Big "A” Co. 2105 Westlake Belleville, Ont., Canada Intensive ^PracllMl Technical C FINLAY ENGINEERING COLLEGE, 10 NO JOKE TO BE DEAF Want a Big-Pay Broadcasting Job? Send for FREE COPY of MODERN MECHANICS BLUEPRINT BOOKLET Plans for a Midget Outboard Hydro (Continued, from page 101) sides (no knots), $1.00; 1 piece fir ply-wood for bottom and rear decks, 8 ft. x 4 ft., $2.75; 4 pcs. pine, 3 ft x 2 in. x V2 in. for ribs (buy 6 ft. lengths), $1.00, 1 piece white pine, 3 ft. x 8 in. x 31/4 in. for transom, $0.25; brass screws (small shanks) $1.00; Casein glue, $0.40; good grade oil paint and spar varnish, $2.00. Cut the side pieces as per drawing leaving plenty of wood to spare. Plane this down to a perfect curve so that the bottom will fit smooth¬ ly. Screw the sides to the transom with long, thin screws about 114 in. No. 4. Bend around center rib and attach to nose block (2 in. x 4 in. x24 in.) Put in the other ribs, cutting them to fit so that the boat will have a straight side from the center rib to the transom and a nice curve from the center to the nose. Take care and plenty of time and do this well, measure often and correctly. Be careful that the boat does not warp during this operation. Next put the bottom piece on. Do not cut this out of the middle of the plywood as you will need this scrap for the deck. Do not cut too close to the sides when fitting to the frame as the edges can be planed down much better this way. Use plenty of glue as per directions on the package. Space screws on the bottom about two or three inches apart. These screws should be three-quarter inches No. 4 or 5. Fix a dash¬ board across the center rib and build the deck framework from this to the nose for a linen cover. A sheet will do unless something more fancy is wanted, but of course will cost more. The motor mount is a piece cut from an 8-inch plank and bolted to the transom. This will have to be adjusted to the type of motor used. It is best to put this on after the rest of the boat is finished. Chines can be put in and a keel piece also, which will make the boat stronger, but do not try this unless you are equal to the problems that will turn up. Motors may have to be speeded up to make (Continued on page 135) Last Word in Houses — 'Bungalette’ (Continued from page 122) contour of the landscape. It can be built of lum¬ ber, brick or hollow tile. It can be placed on a 36-foot lot. The home offers standard equipment, two bed¬ rooms, living room, kitchen, bath, sun porch and large dining alcove all on one floor. While there are no upstairs sleeping accommodations, never¬ theless the enclosed porch equipped with case¬ ment windows offer lounging quarters. Cost should range around $5000 and perhaps less if the house is built of lumber. In brick it will cost Plan No. 4-W-65 is an English type four-room bungalow. An ideal place for a family, of three or four people. A sun porch can be added if you wish more room. While there is no formal dining room the double window next to the fireplace will provide a pleasant place to set a table. The house can be built on a 45-ft. property. The cost should be around $3500 according to the designer. 128 Thank You jo. Mentioning Modem Me

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BE WELL]; YOUNG* STRONG _ Um 6m Make BIC PROFITS' * 21 FOLDERS — ALL PARCHMENT )ination offer immediately. A startling r. WALTHAM ART PUBLISHERS, SECRETS of Beautiful Dancing RCA INSTITUTES, INC. Dept. MM9 75 Varick St., New York 1154 Merchandise Mart, Chicago Recognized Standard in Radio Instruction Since 1909 Putting Design Theories to Acid Test ( Continued from page 85) laboratories for over a year. The autogiro has been put through all sorts of tests and trials. Landings have been made with it when it did not roll forward as much as one foot after touch¬ ing the ground. The most efficient size, shape and position for wing slots and flaps is a subject which has been carefully worked on for many months. One very interesting study now being made at the laboratory pertains to the shape of the hulls and pontoons of seaplanes. Nearly every country has a different kind of a hull or pontoon for planes that land on the water. It would seem that manufacturers believe efficiency in this par¬ ticular thing rests with the nationality of the designer. The technicians, however, believe that there is a definite shape for the most efficient hull and they mean to find out what it is from a purely scientific standpoint. Then when the tests show it to be the most efficient, manufac¬ turers can use it. A two thousand foot water runway forms a part of the wind tunnel labora¬ tory. An electric trolley wire runs above this. An apparatus is built over this which runs like a street-car and a log or piece of wood shaped like a boat hull can be dragged along this water¬ way at about forty miles an hour while instru¬ ments record the amount of drag, suction and other forces acting on it. One important thing learned in this particular research is that the forces which must be counted in the formulas for pontoons and hulls are about ten times as complicated as the regular wheel landing gears. The density of the water and the suction together with the spray are factors that are hard to tie in with wing lift at all stages of the “step off.” It has already been found that the spray which ordinary hulls and pontoons kick up in front of a seaplane produces a marked retarding effect. Therefore, one problem is to find a hull that will not kick up so much spray. Hundreds of models must be dragged through the trough to find this out, unless luck favors the engineers. When the most efficient seaplane hull is dis¬ covered there will be a rush to build speed boats on the same line and the design will spread to big steamships. There is no direct profit derived from the work of the aeronautical laboratory. Science and the commercial world may profit by the research discoveries and the Government comes in for its share through these routes. The Government runs the laboratories and of course no direct profits can accrue to it, but when discoveries of military value are made, it may keep them for its own use. Anybody may have aeronautical equipment tested here — provided the committee believes it to be of sufficient value. But most of the work is done upon the initiative of the en¬ gineers themselves after approval of the chiefs. Most of the problems are those of pressing need in the field of aviation. An example of these is the formation of ice on airplanes and airships; “blind flying” instruments; how to get more pow¬ er out of internal combustion engines; better motor fuels; etc. An extremely interesting discovery has been 130

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Putting Design Theories to Acid Test made recently in the power output of gasoline motors. But “discovery” is scarcely the right word to use. It was the result of long, painstaking work in figures and tests. A method was worked out for clearing the exhaust gases from an engine cylinder and at the same time giving a slight boost to the intake pressure, and 18 per cent greater power was then obtained. In the words of the official report on this subject: “The clearance volume can be efficiently scav¬ enged by overlapping the timing of the inlet and exhaust valves and maintaining a slight boost pressure in the inlet manifold. The loss of fuel with the scavenging air can be avoided by re¬ placing the carburetor with a fuel injection sys¬ tem and timing the injection of fuel into the engine cylinder. The result of tests conducted with a single cylinder test engine showed that power obtained when operating with valve over¬ lap and a fuel injection system was 18 per cent greater than that obtained with normal valve timing and a carburetor. The specific fuel con¬ sumption for the two conditions was approxi¬ mately the same.” It does not take a scientist to realize what an increase of 18 per cent means in an aviation en¬ gine or any other kind of engine. The technicians have only scraped the surface of this line of research. It is well known that a big percentage of the energy in the gasoline that explodes in a cylinder is dissipated in the form of heat and every bit of this energy which can be snatched back into useful work means mechanical prog¬ ress. So much energy is turned into useless heat when a gasoline motor runs that complicated cooling systems must be used, as everybody realizes. Most motors use water for cooling but air cooled motors for airplanes have been used for several years. Air cooled motors have thin fins extending out from the cylinders. The air is supposed to carry the heat of the cylinders away and keep them from melting in their own heat. This method of cooling cylinders had been generally thought to be pretty well settled. But during the past few months, the N.A.C.A. technicians have given some study and experi¬ ment to the subject of fin cooling principles. And they have found that, quoting the report on the subject: “ . . . about one half the cooling area of the cylinder does not come in contact with the cooling air because of the breakaway of the air stream from the cylinder.” This knowledge is of great importance at this time when airplane motors of tremendous horse power are heing built with the fin cooling system. A formula on this may soon be issued. In an attempt to remedy this defect in the fin cooling system a blower was devised which would force the air into all the corners where it broke away before and it was found that the cylinders could be cooled more uniformly and more effi¬ ciently by this method. This also opens up a new line of research. Another very valuable phase of research which has occupied the attention of the technicians at the laboratory for a long time is airplane stabil- (Continued on page 135) YOUR OWN“^™« TELESCOPE Same type as 100" Mt. Wilson Telescope. No expe¬ rience or special tools needed. We furnish complete set of instructions and all necessary materials at lowest prices. Send for 1933 catalog on Telescopes, Microscopes and Optical Supplies PRECISION OPTICAL CO., 991 E. 163d St., NEW YORK NEW HAIR OR NO PAY Grow new hair, end dandruff, falling hair regardless of your age or sex. No charge if I fail. Bar¬ ber, Beauty Shops recommend it. My booklet "Scalp Health” tells all. It’s FREE. CLARA BELLE ATKIN CO. Suite B4S9, Sexton Bldg., Minneapolis, Minn. STAMMERER Write for Free List of ethical successfully correct^H^eech^defi 36 Newburv St. Suite 404 E S iber Wke 131

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WALTER E. HULL, Box 246-A, WARREN, OHIO Portable Sail Rig Will Sail Rowboat (Continued, from page 119) two twelve-foot sides. Use a nail to make the holes with, but break no threads of the canvas while making the holes. The holes are four inches apart, from one corner to the other, on both twelve-foot sides. Now place the spars, hinged together at one end, along the hemmed sides, and stretch the cloth out so there are no wrinkles. Through each hole in the canvas, run a foot of cotton fishline (the uncolored kind is best) so that six inches lies on each side of the canvas. Bring the ends under the canvas, and tie a square knot so that it comes under the" hem, but not tight enough to wrinkle the hem. Pass the free ends of the fishline around the spar at the near¬ est point, and tie a second square knot. Do this with each of the holes all along the two twelve- foot sides. (See Fig. 1.) For the mast, take a six-foot length of cypress, four inches square at one end, and three inches square at the other. Round -edges and corners with a plane. Bore a three-quarters-inch hole two inches from the three-inch square end. Two inches below this first hole, toward the middle of the stick, bore a second hole, the same diameter. Remove the wood between the two holes with a chisel, so that it forms an oval slot. Knock the pin out of a small awning pul¬ ley, to get the wheel inside the frame. Select a drill the same size as the pin, and bore a hole through from the opposite side of the mast from the oval slot, in such a manner that the hole passes through the slot in the center of it. Put the wheel into the slot, and fasten it there with a bolt through the last hole bored. This forms a sheave at the top of the mast. Taper the four-inch-square end of the stick, so that it will fit into a ten-inch plumber’s nip¬ ple, three inches in diameter. The nipple should be threaded at the lower end. The lower end of the stick must fit very snugly into the nipple. The bucketboard is made of a four-foot length of cypress, ten inches wide and two inches thick. This piece must be absolutely sound and free from all knots, since all the strain of the tackle comes directly upon it. Find the center of one side, and bolt a plumb¬ er’s floor plate, three inches in diameter over the center mark. Countersink the bolts on the lower side of the board, so the nuts are flush with the side of the board. (Fig. 2.) The leeboard proper is made of a four-foot length of pine, free from blemish, ten inches wide and one inch thick. Feather the edges, as a canoe paddle is feathered, and round the upper end. In the middle of the arch formed by rounding the top of the board, bore a three- quarter-inch hole, and eighteen inches below this, near one edge, bore a second three-quarter- inch hole. The first hole is to receive the king¬ bolt, while the second is for the rope. The edges of the second hole therefore must be rounded with a taper file. The kingbolt is five inches long, and % inches in diameter. It passes first through the hole in the top of the leeboard. Then slip on a washer, large enough to cover entirely a roller skate wheel’s diameter. Then slip on a roller skate 132

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Portable Sail Rig Will Sail Rowboat wheel of the ball-bearing type, and a second washer, just large enough to cover the inner rim on the wheel, follows. Drill a % -inch hole through a six-inch square block, two inches thick. One side must be coun¬ tersunk to take the nut from the kingbolt. Slip the block over the kingbolt with the squared hole away from the last washer, and put on the nut. Tighten moderately. Saw away the remaining length of bolt. Bore a one-fourth-inch hole in each corner of the block. Bolt the block to a two-foot length of sound board, an inch thick and ten inches wide, by passing stove bolts through the block. This, if properly done, will conceal the nut end of the kingbolt entirely. (Fig. 3.) The steering block is easy. Merely an eight- inch length of two-inch thick cypress or pine, six inches wide. Bore a hole in one edge large enough to take an oarlock cup. Put the oarlock cup in place, and wedge. Now you are ready to get ready for a sail. You will need two lengths of clothesline (the woven kind is best). One length is eight or ten feet long, and the other is fifteen feet long. You will need about four feet of sashboard, too. Six “C” clamps complete the tackle. A word of caution, in buying the “C” clamps. Get drop (Continued on page 136) Cruise Under Water in One-man Sub (Continued from page 107) stream-line portions of the superstructure. If this is not sufficient, molten lead may be poured into the cones, and weights may be welded onto the lower portion of the bow cone and the lower stabilizing fins at the stern. From the tow ring a rope at least 100 feet long should be run to the towing craft, and the deeper one intends to descend, the longer should be this rope in order that the pull shall be as nearly horizontal as possible. Care should be taken not to submerge too sud¬ denly. From a surface speed of 30 miles, the craft will check to about 15 when submerged, and the shock of this transition should be spread over as much time as possible. The air inside the boat will be sufficient for approximately half an hour’s stay under water. For safety’s sake it is well to have an oxygen tank as part of the equipment, and this can be attached just inside the bow cone within easy reach of the operator. Help Kidneys If poorly functioning Kidneys and Blad- O der make you suffer from Getting Up Nights, Nervousness, Rheumatic Pains, Stiffness, Burning, Smarting, Itching, or • Acidity try the guaranteed Doctor’s Pre¬ scription Cystex (Siss-tex) — Must fix you up or money back. Only 75c at druggists. WANT STEADY JOB? A MONTH Work for U, S. Government MEN— WOMEN 18 to 50 nix and In 133

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Fortunes Waiting for Inventors DICTIONARIES — STANDARD ENGLISH (Continued from page 87) States alone about 100,000,000 electrical outlets. These outlets require that the prongs of the elec¬ trical plugs used in connection with them be in¬ serted in a certain critical position. What is really needed is an outlet that will receive a plug at any angle. Thus in place of the openings in the outlet being confined to small slots there should be but a single opening and this should be in the form of a continuous circle. Such an improved article de¬ signed right and able to pass the Fire Under¬ writer’s tests would be worth at least $100,000 cold cash. Several hundred million toothbrushes are used in the U. S. A. every year. To the inventor who will invent some sort of a simple substitute for the toothbrush that will screw directly onto the end of a tube of toothpaste and through which the toothpaste will feed automatically when the tube is pressed there will be a fortune that will make Gilette’s fortune from the safety razor look like small change. The thing should be very cheap and does not have to be made of bristles if a good substitute can be found. Get busy you inventors. Here is something big to shoot at! Those who like to work on problems with a little more complication will do well to devote their attention to a simple method or device that will eliminate the foreign matter that accumu¬ lates in the bottom of the gas tanks on automo¬ biles. While we have gas filters, they also have to be cleaned out occasionally. What is needed is a device built right into the bottom of the gas tank into which this foreign matter will accumu¬ late and through which it may be removed very easily. Not only would this eliminate the gas filter but it would also eliminate plugged gas lines which the gas filter does not prevent. That trick will be left for the independent inventor. There is a large fortune waiting for a successful device. Some years ago a man made himself a great fortune with the “Mama” doll; that is the doll that would say this word when it was tipped backwards. There is a similar fortune waiting for the man who can supply some sort of a de¬ vice that can be attached to a boy’s velocipede and that will make it sound like a real auto¬ mobile. There should be the sound of a smooth, even running motor and, naturally, the device should be geared or belted to the rear axle of the car or cart, the sound being available only when the device was actually moving. Those who understand optics and projection will be interested to know that an auto stop light could be used that, in place of merely flashing red or green, would actually throw the word “S T O P” on the pavement at night. It would flash red also. In other words in place of having just an ordi¬ nary stop light the autoist would have what would amount to a small but powerful magic lantern on his car and this would flash the warn¬ ing signal on the pavement at night. While the device would work during the day time it would not be seen. However, this would not by any means defeat the invention for the simple reason that most rear-end collisions happen at night. 134

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Putting Design Theories to Acid Test (Continued from page 131) ity. The mechanics of airplane stability were worked out many years ago, but strange as it seems, it has been applied to airplane design in a very limited manner. This is due to the great complexity of the flight formulas. The cut and try method is still the basis of most airplane design and manufacture. General principles are adhered to but only in a general way. This is why airplanes have been built on the same broad lines for so many years and it has led to the “conven¬ tional” airplane. Not one single airplane of new design has ever been built, probably, which has not undergone many changes after it was flight tested. And this refers to the “conventional” type, not just the freaks. This is because nobody has taken the patience to figure out ahead of time just what a new type airplane will do when it gets into the air. The mathematics of the problem is so in¬ volved that it is really easier to build a plane along generally approved lines and make the corrections on the real product after test flights. The designers and manufacturers today know whether their new model plane will fly because they cut close to the pattern of planes that have already been flown, but they do not know wheth¬ er it will be tail or nose heavy, how it will react to the controls, whether it will “hunt” in the air, i. e. jump like a live baseball, or whether it will come out of a tail spin. The technicians of the N.A.C.A. intend to simplify the mathematics of the problem for everybody to use. In the words of a recent statement from the committee: “A study of the entire stability problem is now being made at the committee’s laboratory for the purpose of preparing the data in easily usable form so that a designer may readily compute in advance both the longitudinal and lateral stability characteristics to be expected in his airplane.” Thus flying is being reduced by the experts of the National Advisory Committee for Aeronautics to simple figures. And it is being reduced to figures in order that the process may be com¬ pletely reversed — that the figures may be fitted to the wings. Plans for a Midget Outboard Hydro (Continued from page 128) this job plane and the best way to do this is to put them in the best running condition pos¬ sible. Take out the inner core of the muffler and punch larger holes in the outer case. Cut the throat of the carburetor larger and smooth with fine sandpaper. Raise the spray jet in the throat as high as possible and enlarge the holes in the jet. If you wish to take the chance, though I don’t advise it, trim a little off the blades of the regular propeller. After mounting the motor see that the cavitation plate is about one-half inch below the bottom of the boat, or rather see that the propeller is barely in the water when planing. This will take quite a bit of experimenting to get the proper result. Figure out all the little things that stump you by yourself and remember that I built this alone with no plans, so surely you can do just as well. LEARN in CALIFORNIA TELEVISION-RADIO TALKING PICTURES Dirt Track Racing FIND GOLD With Guggenheim Gold Detectors NEVER FAILS GUGGENHEIM EQUIPMENT COMPANY Wholesale Price $25.00 Ceiling suspension. Beautifully finished. Dealers order one. Will replace several ordinary ceiling fans. 20,/2-inch aluminum propellor, 1/2-inch bore, * $3.85. Michael Electric Co., Fort Worth, Texas LIKE TO BUILD THINGS? Modern Mechanix How to Build Manual contains hundreds of keen projects.

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WANTED MANUFACTURERS of a life-time f PATENTS HIGHEST REFERENCES RED BEST RESULTS Send drawing or model. WATSON E. COLEMAN 724 9th St., N. W. Patent Lawyer Washington, D. C. HIGH BLOOD PRESSURE Q.UICK RELIEF, OR YOU ONLY PAY INVEtr TORS Write today for FREE BOOK, HOW TO OBTAIN A PATENT and RECORD OF INVENTION— or send Draw¬ ing or Model of your Invention for Examina- t,on- MAIL COUPON TODAY! Promptness Assured with Best Results MILLER & Ml LLER REGISTERED PATENT ATTORNEYS 1 1638 Woolworth Bldg., Dept. B, New York City | I 203 EARLE BLDG. WASHINGTON, D. C. j . Please send me your Free Book, "How to Obtain l a Patent,” and your "Record of Invention” form. | | NAME . . | ADDRESS . I L— ____J HOW TO BUILD 20 BOATS 50 Cents at All Newsstands Portable Sail Rig Will Sail Rowboat (Continued from page 42) forged steel-jawed clamps, with a six-inch jaw. Cheaper kinds can be bought, but they may break, and a break is both costly and dangerous. Now go hire a boat. Get a boat with three seats in it, counting the stem seat. That’s the only thing you need to be fussy about, except¬ ing that you ought to ask if the boat leaks. Place the bucketboard from one seat to the other, in the middle of the boat, parallel with the keel, and directly above it. The floor plate wants to be upwards. Into it, thread the nipple on the foot of the mast. The sheave should be running the same way as the keel, and you run the short length of clothesline through the sheave. Tie the stern end of the line to a point on the uppermost spar in a slip knot. The point on the spar must be determined by experience, since no two outfits balance alike. When , once determined, it is a good idea to paint a black band around the spar at that point. Be sure your boat is headed right into the wind at the wharf. Now pull up the sail, so the lower spar clears the sides of the boat by ten or twelve inches. At the point on the mast where the lower spar touches, take two wraps around the mast with the four-foot length of sashcord. Tie it firmly with a square knot first, leaving both ends of equal length. Now tie about a half dozen or ten half hitches in the free ends. Then tie the remaining ends firmly to the lower spar. This forms what is known as a “jaw.” It permits the sail to “swivel” easily on the mast, but the sail can’t get away from the mast at that point. Tie the long length of clothesline to the rear tip of the lower spar, using two wraps and a couple of half hitches, or a slip knot. Some pre¬ fer the slip knot, because there is less danger of the line coming loose. About half-way back on your lower spar, hang the leeboard over the side of the boat, and clamp it firmly in place, with the sideboard on the outside of the boat. It makes little dif¬ ference which side of the boat it is placed. Run a short line from the hole that is lowest on the leeboard, back to the stern seat of the boat, but do not tie it. Clamp the steering block in the middle of the stem of the boat, with the oarlock cup up, and put an oar into the cup. (Fig. 5.) Untie the bow of the boat first. Now seat yourself on the stern seat. Take the line from the rear end of the lower spar in one hand, and cast off the stern rope to the wharf. You’re moving. Grab that oar, behind you, and miss that green rowboat that’s coming in, with the fat lady in it. No matter whether you’ve ever sailed or not, after fifteen minutes in this boat, rigged with the portable sailing rig, you’ll be a sailor. When you get back to the boat livery, sun¬ burned until your eyebrows are white, simply unclamp the six clamps, furl the sail around spars and mast. Toss the bucketboard, leeboard tackle and steering block into the rumble seat, tie the sail and spars on the running board, and pay the boatman. Thank Yo

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Dempsey on Mechanics of Boxing (Continued from page i2) delivering a blow. The principle of the lever is one of the prime fundamentals of boxing. If you understand this point you can understand how a strong right or left arm can transmit or modify force and motion. You’ve got to look at the hu¬ man body as an engine. In reality, it is an engine of many parts. “That big mechanism is possessed with energy, potential and kinetic power. It has one enormous factor that other mechanical instruments do not possess, and that is brain power. Take an auto¬ mobile or an airplane, start the engine going and let that vehicle proceed without human guidance and you are bound to see that machine strike ruin and disaster. Proper guidance, then, is a part of the fighter’s scheme of beef-and-brawn. There can be no shirking in upkeep and maintenance where the fighter’s body-engine is concerned. “Take the left hook, by far my favorite punch. Its source of strength is in the left shoulder. It’s short and fast and murderous. “There’s perfect co-ordination in that left hook. The fist and elbow turn quickly and drive for only about six inches. The propulsion which the hook gets from the shoulder as the body swings with it gives the impact its effectiveness. You learn time precision by practice — then it becomes a matter of instinct. “The jab and the right cross are worked on the leverage system. The same might be said for the uppercut. The body proper acts as the solid foundation and the shooting arm, backed by that firm structure working as an axis, gives the fist the force for most damage. The punch must be straight out with the body behind it and not by pulling the arm back and then shooting out. This is not only a waste of energy, but also useless and warning the other fellow of the blow. “Footwork is a vital part of the boxing profes¬ sion. Here again you encounter science and me¬ chanics principles. Any architect will tell you that big buildings sway a little in windstorms. If they didn’t, and were stiff and unyielding, they would not be able to withstand the powerful gales and would be smashed down. The same applies to the fighter. He must not pose stiffly. He must relax, possess agility. Bobbing and weaving, ducking and dodging are all a part of the expert boxer’s tricks. “The successful boxer must have stamina and this is attained through rigid scientific training methods. Road work, work-outs in gyms, spar¬ ring and shadow-boxing, strict diet, regular hours, capable handlers and trainers, all these are part of the ambitious fighter’s repertoire. The fight game calls for strong character and good habits. You can’t get to the top without these essential qualifications. “As a promoter, I and my associates are always going to keep an eye out for worthy timber. There’s no telling from what part of the country the next big drawing-card is apt to spring. I’ve been through the whole rigmarole, and I don’t think I’ve missed many of the rigors and trials of the business. I’m going to give any strong cham¬ pionship candidate I pick out a fair chance. I want to encourage potential champs. ^*ASy$5.ADAY^ MVSTERY.GAS UGHTER \ Gall ■ a* Ibis Ml k"e°R~S^NEW method MANUFACTURING CO. ACT NOW New Method Bldg., Desk MG-9, BRADFORD, PA HAENEL “100 SHOT” REPEATER .95 i Catalog — Colts, S.&W. Rifles, Binoc TRADE-MARK byI CONFIDENTIAL ADVICE — DO IT NOW1 Send for Free Copy of Modern Mechanix Blueprint Booklet echanix and I Thank Yo tioning Modern Me

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BEWARE RUPTURE THAT “DOESN’T BOTHER MUCH” HfSSSlli

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MenPast40§ A V ~ \ X \/ X , \ _ mm/, M E ’ > l 1 Hr !-f W ^ Wf ' '* u - ; Stop Getting Up Mights! It is a Symptom of Vital Gland Failure! MANY men past forty know the real mean¬ ing of a weakness that attacks millions of men in middle life. Doctors say that night rising in many cases is a serious symptom — one of Nature’s surest warnings of the degenera¬ tion of a vitally important male gland — the prostate. So little-known is this gland that few men even realize it exists. Yet if unchecked, this diseased gland can actually lead to serious sur¬ gery. It makes the victim get up, from two to ten times a night. It often causes weakness and pain in back and legs. The victim is frequently “blue”— worried unaccountably— always tired, victimized by headaches, and loss of vitality. Frequently this gland degeneration is the real cause of severe constipation and painful piles. Yet this .condition now can be easily com¬ batted, by an aniazing scientific treatment now being used by over a hundred thousand men. This treatment is called Thermalaid. Includes no drugs — no medicines, diets, violet rays or massage. Its simple, yet radically different principle has produced amazing results in recent New York hospital tests. Yet it is so simple and easy to use that it may be used right in your own home. It has already helped so many thousands of men, that it is now offered under an amazing agreement. If Thermalaid does not actually make you feel ten years younger in seven days, we agree to refund your money ! If you have any of these symptoms, you should investi- gate the Thermalaid treatment at once. Right now we are offering, free, a remarkable book called “Why Many Men Are Old at 40,” which explains these symptoms and tells W. J. Kirk, President, The Electro Thermal Company, 3869 Morris Ave., Steubenville, O. TO MEN PAST 40

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Mechanical .SPOT NEWS 0/ the Month PRICE 15 CENTS 32 Modern

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LOS c^NGELES RACES Trove <AIR THRILLERS by JAMES BOWLES 34 Modern Mechanlx and

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World’s ^Deadliest Weapons W ill ‘WAGE NEXT WAR Modi

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FLYING with TICCARD Behind the newspaper headlines relating the progress of Prof. Piccard’s stratosphere flight lies this fascinating story of the scientific details of the amazing aeronautical adventure. .. ...w ..iysterio-„ — - - w..« rom interstellar space, the pulse of le civilized world beats a little fast- imaginations of millions of peo- aroused to new heights by the To the awe-stricken public following in the newspapers the trail of the stratosphere navigators, the flight is an amazing adven¬ ture into the heavens. Behind the scenes, however, lies another adventure which will elicit the keenest interest for Modern Me- chanix and Inventions readers. The extensive preparations made for the flight, the intricate calculations involved in gondola, and the way the intrepid space navigators live during their journey through the void — all these details make a fascinating story within a story. Filling the huge balloon in preparation 4- - spectacle. Into an ap^pen- SH-Swa K==s in the STRATOSPHERE Septembei

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22

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Strange ‘PERILS ofdMaking clMOVIES Si Beneath the Sea and Inventions

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(MECHANICAL Wonders of (Chicago WORLD’S tycdr

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When MOTHER EARTH tBloivs Off 5TEAM mb ^mmsm . j

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Mew ‘Inventions for 78

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Cutting TLANES through the & hird "Degree ^mSw?7

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t&ake thrilling Underwater Qruise in ONE-c^AN 5UB

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