Popular Science Monthly 1925-10: Vol 107 Iss 4

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925 INVENTIONS S ul ary DISCOVERIES RADIO AUTOMOBILES CNCEC i wiasior FounpED MONTHLY 1872> HOME WORKSHOP: NY MERE RAO Me ssa nehed oe Tae a ee RS rine et 2 ah 8 Sa Sa See ES Ph ee se = Pent % OCTOBER Strange new gas masks to protect animals in warfare 25 CENTS |Beginning—The Story of Houdini—Page 16 |

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The Perfected C-H Rheostat Designed to radio engineers’ specifications. Re- volving drum type with one hole mounting. All spring tensions adjusted at factory and undis- turbed by mounting. Instrument cannot turn on panel. Very small size—less than % inch back of panel and narrower than standard socket. Operation smooth and quiet. 6 ohms, 15 ohms, and 30 ohms—perfect control for all tubes and their combinations. C-H Radio Pobantiometer Similar in construction to the perfected rheo- stat. 400 ohms and only a little larger than a silver dollar. Perfeet, smooth is back lash or sticking. Price $1.0 Operating parts built as unit—the C-H Perfected Rheostat is not disman- tled for mounting on panel. Rheostat is locked in place and knob positioned with- out a single set screw.

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The C-H Low Loss Socket The revolutionary socket design that created a sensation everywhere. Thin ORANGE Bakelite shell. Base of heatproof Thermoplax—terminals cannot loosen under heat of solderin, iron. Contacts grip both sides of eac tube prong and are SILVER plated to prevent corrosion losses. Preferred by careful builders at 90c—now 60c because of huge production savings.

C-H Radio Toggle Switch The C-H The newest idea in panel switches. Radio Switch et oe paler emote The original radio switch. Millions in use. One one hole mounting — neat etched hole mounting—high capacity mechanism. The plate for panel provides definite only radio switch approved for 110 volt circuits by * indication. Quiet, easy operating the Underwriters Laboratories. Ideal for battery- switch nection, less sets or higher voltage circuits. Many switches now have buttons to look like the C-H but the jet mechanism cannot be pgp De- nd the orange and blue box for satisfaction. CUTLER-H name Cutler-Hammer has held an enviable position in radio, Consistently from the earliest days has the C-H trade mark been synonymous with proper design and unusual pre- cision. Radio builders everywhere justly had faith in these foremost engineers and millions of their radio parts in the orange and blue boxes have helped build receiv. ing sets of quality. Better Sets at Lower Cost These millions of sales have brought down manufacturing costs and today this quality carries no premium. Demanding the C-H trade mark now not only insures satis faction, but provides a saving. Dealers everywhere are ready to serve you. If yours has not yet stocked any C_H part you desire, send us his name and we will see that you are supplied.

"THE CUTLER-HAMMER MEG. Co. Member Radio Section, Associated Manufacturers of Electrical Supplies MILWAUKEE AND NEW YORK

j The C-H Radioloc ! The radio switch that locks with ; 4 akey. Just the thing for the home iff ‘| ~~, ; with children—for the protection Vio ~~. | of tubes and batteries. One hole \ Y, } So ga operation. ie / all C-H radio parts, hacked in ‘ ) a J orange ane blue boxes. k for hem—and the C-H trade age §

—z— Buy Your Radio Parts by Name —<—

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1as held 1 radio, ays has nymous pte- e justly ers and Orange | receiv: Cost it down ; quality he C-H 2s Satis: Dealers you. If -H. part we will iG. Co, rers of K POPULAR SCIENCE MONTHLY 0 eee CrosleySuperTrirdynSpecial*60. Crosley Musicone *1752 3 Tubes Now give Results Equal to 5 But it is a scientific truth, first demonstrated in the Crosley laboratories and then confirmed by the performance of thousands of Trirdyns the country over. Employing but 3 tubes, the Crosley Super-Trirdyn consistently equals 5 and often surpasses, the more costly 5 tube sets in performance. These astonishing results are simple to explain. Instead of passing the incoming signal once through each of 5 tubes, Crosley design passes it through two of the three tubes several times, each time building up its strength and adding to its volume. Even the technically uninitiated can see the advantages: simplicity instead of complexity; fewer dials to adjust; sharper accuracy in selecting Stations; greater clarity; greater volume. Yet that is not all. Simplicity of design and fewer parts make manu- Gober i improbable doesn’t it? facturing costs lower and bring about a lower cost to you. This, combined with the economies of gigantic pro- duction makes it possible to offer this quality receiver, the Super-Trirdyn, at this remarkably low price. For Crosley is the world’s largest builder of radio sets—owning and operating parts factories, cabinet woodworking and assembly plants. Listen to a Crosley Super-Trirdyn under the most exacting conditions. Make an unbiased comparison with the most costly receiver you have ever heard. Forget the radical dif- ference in price. Then will you understand why the Crosley Super-Trirdyn represents a genuine achievement in radio per- formance and value which all America was quick to recognize and reward with increasing sales. Write for attractive illustrated cata- logue. Authorized sales and service stations everywhere. BETTER=COSTS LESS ; RADIO THE CROSLEY RADIO CORPORATION, CINCINNATI, OHIO © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. Super-Trirdyn De Luxe Combination Super-Trirdyn De Luxe .. . .$ 60.00 Musicone De Luxe ....... 27.50 Console Table. .......... 25.00 COMIIG in ieicd os ce eeel $112.50 ADD 10% TO ALL PRICES WEST OF ROCKY MOUNTAINS Crosley manufactures receiving sets which are licensed under Arm- strong U.S. patent No. 1,113,140 and priced from $9.75 to $60.00 without accessories. Crosley owns and operates WLW first remote control super- power broadcasting station.

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Popu OCTOBER, 1925; Vol. 107, No. 4 25 cents a Copy; $2.50 a Year

lar Science Monthly The Magazine of Invention and Discovery Published in New York City at 250 Fourth Avenue

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Coming Next Month Do You Have Trouble Driving in Heavy Traffic?—Gus and Joe’s valuable hints in next month’s issue will help you. How to Use Glue in Your Home Workshop—A national authority on glue and its uses offers practical advice on how to insure joints that will hold in doing common household repairs, or in building furniture and doing other wood work. The Last Word in Radio—New facts about low-loss coils from the Radio Laboratory of the Popular Science Institute of Standards; how to build a good crystal set; hints for installing a commercial receiver—all in next month’s Radio Department.

More than 200 other fascinating articles and pictures, giving you all the news of radio engineering, science and inven- tion, strange and unusual things people are doing, together with practical ideas for the automobile, the home, the home workshop, and the use of tools and machinery. HO UDINI, the most mysterious man in the world, begins his own fascinating story in POPULAR SCIENCE MONTHLY next month — a chronicle frankly revealing as- tonishing secrets from a life packed with magic and romance. When you read Ray- mond J. Brown’s vivid picture of Houdini the man, on page 16 of this issue, you won’t want to miss a single word of this amazing series, starting in the November number.

Houdini (right) explaining tricks of fraudulent mediums to Raymond J. Brown, whose fascinating character portrayal of the world’s most mysterious man appears on page 16 of this issue. Houdini’s own story begins next month

POPULAR SCIENCE MONTHLY Issued monthly. Single copy, 25 cents. Yearly subscription to United States, its possessions, and Canada, $2.50; foreign countries, $3. Entered as second-class matter Dec. 28, 1918, at the Post Office at New York under ‘the act of March 3, 1879; additional entry as second-class matter at Dunellen, N. J. Entered as second-class matter at the Post Office Department, Canada. Printed in A. Copyright, 1925, by the Popular Science Publishing Co., Inc. The contents of this miagazine must not be reprinted without permission. In presenting in its editorial columns numerous stories of new products of applied science, POPULAR SCIENCE MONTHLY does not underwrite the business methods of the individuals or concerns producing them. The use of PoPULAR SCIENCE MONTHLY articles, or quota- tions from them for stock-selling schemes is never authorized. O. B. Capen, President and Treasurer; R. C. Wilson, Vice-President; A. L. Cole, Secretary.

bi This Issue Popular Science Institute of Standards .. Gas Masks for War Horses 'y Innis Brown Our Great $10,000 Contest A Romance of the Microscope.......... By Peter Vischer Giant Mother of Airplanes Houdini—The Most My: ysterious Man... . By Raymond J. Brown Uncle Sam’s Cruising Repair Shop By Frank Parker Stockbridge A Woman Blacksmith. ............... we Science gy the Ocean By Edgar C. Wheeler A Mechanical Doctor for Motor-Cars. . . By Fritz Blocki Just What Is Evolution?............. Our Hidden Foes in the Air By Newton Burke Can Man Reproduce the Sun? By Frederic M. Delano An Ice-Locked Island of Mystery ..... : How to Pick a New Boss By Samuel S. Board Army Tests “Flivver Cav alry”” He Puts His Hand in the Lion’s Mouth .. By Robert E. Martin New Mileposts of Discovery Safety at the Switches New Color-Sorting Machine Chewing Machine Tests Beef Novel Gravity Scales Co-Eds Grow Slim by Machinery Hanging Weight Holds Papers Device Limbers Pianist’s Hands Controls Train 300 Miles Away Model Tower Made of Toothpicks .... Where the Diver Met Her Shadow .... A Portable Machine-Shop Smallest Lighthouse Model Story of Bees in Movies Nest of the Largest Bird Mouselike Deer from Ceylon ........ Railway to Be Roofed by Boulevard. . Sky Traffic and Its Progress .. Curiosities from the Motor World . Newest Trousers Press.............5 Se And Other Timely Articles and Pictures

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October, 1925 POPULAR SCIENCE MONTHLY + Oo ar nem a | Pictures IMO is made in eight STEEL handle , 8, 10, 14, 18, 24, 36 and 48 inches: D handle sizes, 6, 8, 10 and 14 inches, handle house! - small illustration) comes packed in individual - all parts replaceable ~ atsmall cost! «6 S picture shows at a glance one of the big features that makes the TRIMO Pipe Wrench the economical choice of the householder, farmer, master mechanic and American industry. When the INSERT JAW in the handle of the TRIMO becomes worn or dull through many years of service, all you have to do is to spend a few cents for a replaceable jaw instead of buying a new handle which is a large portion of the cost of a new wrench. This same replaceable feature applies to all TRIMO parts, making this rugged tool low in FINAL COST. But it’s the masterly design of the TRIMO that most wrench-wise users admire. Note the NUT GUARDS, for instance, how they pro- trude slightly above the wheel, thus keeping the wrench in perfect adjustment when used in close quarters or laid down. TRIMO has a STEEL frame that WILL NOT BREAK—your guarantee of safety and durability. For these and many other reasons, people who KNOW never quibble about paying a few cents more for this— America’s super- quality Pipe Wrench. At all hardware, mill and plumbing-supply stores. Insist on TRIMO—accept no other. TRIMONT MFG. CO., ROXBURY, MASS. America’s Leading Wrench Makers oe : he ee For Nearly 40 Years Besides Pipe Wrenches, the TRIMO line includes Pipe Cutters, Pipe Vises, Monkey Wrenches and Chain Wrenches. The name TRIMO stamped on any tool is your guarantee of quality. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

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How Our Subscribers Make Use of the Institute of Standards One Day’s Mail Besides letters from all over the United States, the Popular Institute of Stan- dards receives let- ters from every corner of the world only one on the thousands of letters that come to the Popular Science Institute of Standards. Readers from every continent in the world are among those who have taken advantage of the service the Institute offers. The writers of these letters are inter- ested in different kinds of radio and tool equipment, but they all have the same essential reason for writing to the Popular Science Institute of Standards: They want to “play safe’’ in their selection of such products, and they know they will be safe if they are guided by a staff of expert engineers when they buy. The inexperienced, as well as_ the experienced, realize the advantage of restricting their choice of radio and tool products to ones that have passed rigid scientific tests in the laboratories of the Popular Science Institute of Standards. Men engaged in various fields of radio work, as well as some of the largest dealers and jobbers in radio apparatus in the country, are using the List of Ap- proved Products of the Popular Science Institute as their guide in buying radio equipment. Likewise, mechanics and hardware dealers of many years’ ex- perience ask what tools we have approved. Here is a letter, typical of many that come to the Institute: I am taking the liberty of inclosing an ad- vertisement from our local newspaper of the radio set, and I would respectfully request your opinion as to its efficacy. I have considerable.faith in the products approved by the Popular Science Institute and feel that my judgment in adopting the policy of buying only such products has saved me from making serious mistakes. I would therefore appreciate your indorsement before I send the order for this radio set. —P., B. J., San Francisco, Calif. A man who is general storekeeper for a railway system writes as follows: | NCLE SAM’S postmark is not the POPULAR SCIENCE MONTHLY I have read with keen interest of the good work that you are doing with regards to approving tools and radio products that have withstood scientific and practical tests in your laboratories. Will you be good enough to send me a list of such tools as have met with your approval. This, I am sure, will be of service to me, not only in my business, but for my personal purchases, as I am very much interested in tools of all designs and types and am con- tinually purchasing them. Before closing, I would like to say it is my opinion you have started something in this work that will be of enormous value to users of tools.—S. O. M., New York, N. Y. Many readers who have been guided by the findings of the tests of the Popular Science Institute of Standards write later to assure us of the satisfactory service received from the equipment purchased on our recommendation and, almost in- variably, they add a statement similar to IS) POPULAR SCIENCE Monthly Guarantee The above seal on an advertisement indicates that the products referred to have been approved After test by the Popular Science Institute of Standards. Popular Science Monthly guaran- tees every article of merchandise advertised in its columns. Readers who buy products advertised in Pop- ular Science Monthly may expect that these products will give abso- lute satisfaction under normal and proper use. Our readers in buying these products are guaranteed this satisfaction by Popular Science Monthly. THE PUBLISHERS. Octo! the following: “I told my friends about the great work you are doing and many of them consulted the List of Approved Products you sent me in making thei own purchases of radio and tools.” All equipment approved by the Popular Science Institute of Standards has passed rigid tests made under the direction of Prof. Collins P. Bliss, who is head of the Mechanical Engineering Department and director of Testing Laboratories at New York University, besides being director of the Popular Science Institute of Standards. Under his experienced guidance, and with $300,000 worth of testing equipment at their command, a staff of expert engineers is constantly at work testing tools and radio products. Information regarding the results of these tests is available to all readers of POPULAR SCIENCE MONTHLY. Inquiries and requests for Lists of Approved Products should be addressed to the Popular Science Institute of Standards, 250 Fourth Avenue, New York, N. Y. [* IS obviously impractical for even as: completely organized a bureau as the Institute of Standards to test all products listed in tool or radio catalogues advertised in our columns. Only tool and radio products specifically advertised in POPULAR SCIENCE MONTHLY. are tested and approved by the Institute. Send for List of Approved Products POPULAR SCIENCE MONTHLY will be glad to furnish on request a list of Radio and Tool Manufacturers whose products have been approved by the Institute, after rigid laboratory tests.

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ends about nd many of Approved aking their ols.” che Popular has passed lirection of is head of Jepartment yratories at ides being -e Institute dance, and equipment of expert ork testing results of readers of Inquiries Approved ed to the Standards, k, Noa 1 for even bureau as to test all catalogues Only tool advertised ITHLY. are nstitute. ved LY will be st of Radio e products ‘itute, after | POPULAR SCIENCE MONTHLY SUMNER N. BLOSSOM, Editor October, 1925 Masked Steed of the Future? New gases affecting the eyes of horses may at any moment necessitate the use of hooded, goggle-equipped masks, according to experts. The device shown here is equip- ped with a tube connected with a tank of counteracting chemicals on the horse’s back SKY dark with airplanes, each carrying a quarter of a ton of death-dealing gas! Huge cities laid waste and armies rendered im- potent! This frightful picture of future war has taxed the ingenuity of the Chem- ical Warfare Division of the United States Army in the production of protective devices. Amazingly effective gas masks have been developed for human beings. And now efforts are being turned toward masks for animals—horses, dogs, and pigeons—all valuable aids in warfare. As far as horses are concerned, Nature has helped us in a-very peculiar fashion. She has made horses’ eyes insensitive to all of the ordinary forms of war gas. And, in addition, Nature has provided that horses shall not breathe through their mouths. _ Thus, all we needed to do was to de- sign a mask that would cover the horse’s nostrils in such a way that the animal would be compelled to breathe through, and one of sufficient filtering surface to _ allow the animal to breathe easily. The problem has been solved so well as Masks for War Horses trange Hoods Devised to Save Chargers, Dogs, g r g and Pigeons from Deadly Fumes By Capt. Adrian St. John Corps Area Chemical Officer, United States Army Like an Sreenen Mouse Because the dog treathes through his mouth and his eyes and ears are sensitive to gas, his queer mask covers the entire head, making the animal look like an overgrown mouse that, in a recent test at Governor’s Island, a horse carrying a rider went through a thick cloud of gas without suffering the least harm. The gas mask worn by the soldier was of the standard type, while the horse was fitted with a mask that resembles a huge feedbag, made of specially prepared cloth, impreg- nated with the special compound that absorbs the gas. Curiously enough, horses’ hoofs must be protected against the effects of gas—a problem that has been solved by the use of leather, cloth-lined boots that are laced on tightly. Dogs presented problems more nearly Used in Recent Tests This long nosebag impregnated with chemicals is the latest type gas mask for horses. However, it affords no protection against possible development of a gas powerful enough to affect the horse’s eyes parallel to those encountered with human beings. Their eyes and ears are sensitive to gas. They breathe through their mouths even more than do humans. These considerations made it imperative that the mask designed for canine use should cover the entire head of the animal, as shown in the center illustration. Carrier pigeons do not wear individual masks. That method of providing for them proved utterly impractical in actual warfare. Pigeons always are carried in crates until released. The mask for pigeons, therefore, consists simply of a cloth bag with a drawstring. The bag is slipped over the crate and the drawstring pulled up tightly. The cloth of the bag is sufficiently porous to admit plenty of air, yet it absorbs the gas. HEN it comes time to release a pigeon, the bird is withdrawn as quickly as possible and thrown high in the air. Spiraling straight up, the winged messenger is above the gas cloud before any damage is done. Investigation and experimental work still are going on. Itis possible that some future development may make masks fit- ted with goggles, or a complete covering for the horse’s body an absolute necessity. 9 Sena amen rs

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10 Latest in Headgear Replacing the long, shaggy locks of old-time football warriors, this new style headgear protects nose, cheeks, jaw, and the skull Bucking Harness To aid backfield men to develop driving power, Larry Bankart, former Dartmouth star, devised the ingenious collar shown at right, held by two men

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POPULAR SCIENCE MONTHLY tive Genius on How Scientific Devices and w= Clever Tricks of Training Add to Thrills of Football October, 1935

HILE Sol Metzger, once a famous star on the Pennsylvania football team, was coaching the West Virginia eleven some years back, he reported for work one fall to find a squad composed largely of inexperienced men. They were agile, strong, robust, and full of the desire to play football, but they were lacking, in many instances, even the rudiments of the gridiron game, especially tackling. Metzger worked patiently, trying to teach them the knack of hitting their men low. But the trick of diving at an opposing runner and nipping him just above the shoe laces comes naturally to but few. The tendency is to go in high, grabbing out at the runner like a drown- ing man clutching at a straw. This leaves the would-be tackler an easy mark for a good stiff-arm jab by the runner. Metzger labored persistently, but to little avail, and the situation was growing desperate when one night after practice, he thought of a scheme. When the men went out for practice the next afternoon, they found stretched in front of the row of tackling dummies, at a height of some three feet, a thick, wide board that bore in large black letters the legend, “TACKLE LOW.” The first order of practice that day was a long session at hitting the dum- mies, in which the men naturally had to plunge under that board. The result was startling. Before the end of the season, Metzger’s rookies had developed into a band of savage tacklers. Football is rich in similar experiences, wherein necessity has mothered inven- tion. The human machines that thrill bleacher crowds today are products of training tricks and devices that are a direct application of science and inven- tion. This fall more of these are to be used than ever before. A stunt similar to that just related was conceived by Alonzo A. Stagg, the “Old Man” of the University of Chicago eleven. Stagg found it a tough job teaching his big, heavy linemen to leave their feet in tackling or blocking an opponent. Finally, he hit on the scheme of stretching a two-by-four about a foot from the ground in front of the tackling dummies, and having these big huskies clear that board in launching themselves at the dummies. They left their feet all right— they had to, or else trip over the board. NOTHER scheme of - Stageg’s was the intro- duction of the Ghost Ball, which was to become famous throughout the country. Each fall, Stagg found that not nearly enough daylight was avail- able for drilling his <« charges. As soon as dusk began to fall, it became next to impossible to fol- low the -ball in passing. Then he hit on the idea of having a dozen or so balls painted with a luminous white paint. This solved the problem. Gil Dobie took another tack to meet similar conditions at Cornell. He had the field strung with high power electric lights. To Glenn ‘‘Pop’”’ Warner, coach of the Stanford University eleven, and former mertor at the University of Georgia, Cornell, the Carlisle Indian School, and Downed with a Flying Tackle Practically every big college team practises with tackling dummies such as this—a stuffed canvas “man” suspended from a trolley in such a way that it goes down to the ground with the tackler the University of Pittsburgh, goes the dis- tinction of having introduced possibly more new training tricks and devices than any other man. One of the most im- portant of these is the charging machine,

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tober, 1925 ickle ctises with ffed canvas a way that he tackler s the dis- possibly ‘ices than most im- machine, October, 1925 the Gridiron By INNIS BROWN Mr. Brownis a well-known football critic and writer. In addition, thousands of radio fans are acquainted with him through his broadcast reports of big Eastern games. His expert knowledge of the gridiron is based on three years’ ex- perience as a player on the Vanderbilt College team, which he captained for one year, and also five years as a football referee. a contrivance now used quite generally. This device is a heavily built platform, roughly five feet wide and 10 feet long, mounted on small wheels. Along one side, at a height of about 30 inches, runs a wide padded board. The method of use is‘to load half a dozen men or more on the platform to provide ballast, and then line up from four to six others in a crouching position about the distance from the machine that would separate them from an opposing line. The latter charge against the machine and push it back. Concerted action is necessary to move the device, and unless all charge together, somebody is due for a painful shock. The main idea was to develop driving power in the legs, but the machine also. serves to train men in starting to- gether. Very similar in operation is the “bucking machine” used by Ceoach Bob Folwell in training the Navy gridiron stars. The machine, a large boxlike structure, has heavily padded supports, against which the players charge. ARRY BANKART, former Dart- mouth star and later coach at Col- gate, devised a departure from the charging machine, which can be used to help backfield men in acquiring driving power, and at the same time allow them ° to carry the ball. Bankart’s creation, a bucking harness, consists of a leather POPULAR SCIENCE MONTHLY Stars of the Forward Pass at the Target Range Development of the open style of play and the use of the forward pass led to the invention of this ingenious “‘shooting” gallery at Harvard, to develop accuracy in passing. Each player tries to shoot the ball through one of the three 18-inch holes to improve his throwing ability collar some 15 inches in diameter, to which four leather straps are attached. These straps are fastened to two wooden staffs, which are held vertically by two huskies, while the back carrying the ball rams his way forward, thrusting his head through the collar and catapulting him- self forwatd as far as possible. The tackling dummy is part of the equipment of practically every college team, and is one of the most useful of training aids. This dummy is a stuffed canvas “‘man.”’ It is suspended from a trolley wire by an arrangement by which the tackler’s weight detaches it from its moorings, so that player and dummy go down together as in an actual tackle. One thing about such dummies seemed wrong to’ Walter T. Stall, a football en- thusiast of Brockton, Mass.—the dummy remained stationary while the tacklers approached. To simulate real conditions, the dummy should be running, too. With a new device, patented He Played with a Broken Neck This scientifically de- signed brace’ enabled Ivan Williams to keep on playing right half- back for the Georgia Tech eleven, even witha fractured neck vertebra This Machine Develops Hard-Charging Linemen Navy huskies are seen here practising with the “bucking machine” used by Coach Bob Folwell, to develop concerted action. To move the machine all players must charge at once recently, Mr. Stall has remedied this. His contribution is a portable tackling dummy with leather handles at the top, so that it can be carried by two players, one on each side. These run down the field with the dummy swinging between them, in position to be tackled by a player running from the opposite direc- tion as in the actual game. In the 50-odd years of football de- velopment, there have been many in- teresting changes both in the game itself and in the matter of equipment and appliances. In the early days an out- standing feature of the player’s pro- tective equipment was a thick mop of long, shaggy hair. This abundant capil- lary adornment, a pair of quilted, pad- ded, knee-length canvas pants, and a sweater of sorts, about completed the player’s trappings. But the tousled hair had its disad- vantages. It was too likely to engage the out- stretched hand of an opposing tackler. Then some one thought of a leather skull cap, and the headgear of leather came into existence. | WAS a rough old game in those days, and bloody noses were a common sight, until John Morrill, famous years ago as a_ professional baseball player, con- ceived the idea of a nose protector. He fashioned an appliance of hard rubber that fits over the nose, resting against the forehead, and having a rubber grip to be held between the teeth for keeping it in place. This was the first nose guard. Also came shin guards. Twenty years ago, just before the first beginning of the game, the football player in full regalia was an imposing and picturesque individual. In addition to the trappings already mentioned, he wore thickly padded moleskin pants—some- times a union suit—elbow pads, shoulder pads—a pair of cupped leather pockets (Continued on page 158)

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Sorting a pile ; of entries in t the $10,000 hee Prize Contest 0 = POPULAR SCIENCE MONTHLY of this issue, and POPULAR SCIENCE MONTHLY’s _ sensational $10,000 “What’s Wanted’’ Contest will be over— at least so far as the receiving of entries is concerned. You have until September 30 to submit your solutions in the final monthly contest—which appeared in the September issue—and for the Grand Prize Contest. Many of those who have submitted solutions for each set of eight pictures as they appeared, competing for the monthly prizes, now are submitting complete new sets of the entire 32 pictures, as a final effort to win Grand Prizes. This is not necessary, since all solutions submitted monthly by any individual are held and four sets judged as a unit in the Grand Prize Contest. If, however, you have changed your mind as to the correctness of your original solutions, you may submit, in the Grand Prize competition, as many additional sets as you like, provided they reach the office of POPULAR SCIENCE MONTHLY not later than September 30. For the past four months a dozen competent and ex- ye 20 days from the publication date skilfully presented solutions will win. Manuscripts have been received at the rate of many hundreds a day, the entries in the aggregate running well up into the thousands. Unfortunately, a large num- ber of entrants forgot to write their names and addresses on their solutions, as stipulated in the rules. These, of course, the judges must disregard. Contestants live in almost every country in the world. A Hindu from the interior of India cabled in vain for an extension of the time limit, since his copy of the magazine reaches him three months after publication. A missionary in Central Africa made a similar plea. A veteran of the A. E. F., living in a little Normandy village, wrote of the interest of his neighbors in the contest. The South Seas and the Arctic Circle join with every state in the Union in contributing entrants. MANY of the letters accompanying solutions assured the judges that the writers were certain to win one or more prizes. Several persons sent their Our Great $10, O00 al WHAT’S WRONG Contest! photographs with instructions to use them in connection with the announce. ment of the awards. One reader asked that the judges send his prize money to an address other than that of his home, that his wife might not take it away from him. Another said he was so sure of winning that he had begun negotiations for a home to be purchased with his prize money from the contest. OF COURSE, even with as many as 580 cash prizes to be awarded, some of the contestants who have worked hard and enthusiastically are bound to be dis- appointed. Yet every one of the thou sands of persons who entered will agree, we believe, that whether they win or not, the contest has been most fascinating and profitable. It has sharpened our wits, stimulated our powers of observation, increased our knowledge of every-day mechanical things, and given us ‘many ‘ evenings of worth-while enjoyment. Of the mistakes that John and Mary have made, some have been simple, others more difficult to find. But each one has held some useful suggestion. perienced persons have been kept busy sorting entries and giving them the first reading. Each entry has received equal considera- tion. Those written in pencil on scraps of writing- paper have been handled just as carefully as those more ingeniously and elab- orately prepared. Some of these latter re- veal remarkable originality and no little labor. Yet accuracy is the first con- sideration of the judges, and in awarding prizes, ac- curacy and clearness will outweigh skill of presenta- tion. Of course, all other N Watch for Winners’ Names AMES of the prize-winners in the first of the four monthly “What’s Wrong” Contests, which appeared in the June issue, will be published in our November number—on the newsstands October 10. Winners in the July, Au- gust, and September contests will be an- nounced in the-December, January, and February issues respectively. The Grand Prize winners will be announced as soon as possible after entries close. The editors of POPULAR SCIENCE MONTHLY are awaiting the announcement of the first awards in the contest no less eagerly than ourreaders. And the judges, who are doing their job thoroughly, promise to have the winners of the June contest ready for publica- tion in our November issue, published October 10. The three judges for the contests—Prof. Collins P. Bliss, Dr. Hazen G. Tyler, and Alexander Senauke, M.E., E.E.—all are mem- bers of the staff of the Pop- ular Science Institute of Standards and their de things being equal, the most cisions will be final.

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Ctober, 1923 ‘est! ns to use announce- ader asked » Money to his home, away from SO sure of egotiations th his prize S many as rded, some orked hard | to be dis- the thou- will agree, win or not, nating and our wits, bservation, every-day us ‘many ment. and Mary 2n simple, But each me useful f POPULAR THLY are ouncement rds in the igerly than the judges, their job lise to have the June rr publica- mber issue, or 10. ges for the Collins P. . G. Tyler, senauke, are mem- of the Pop- stitute of their de val. October, 1925 POPULAR SCIENCE MONTHLY 13 A Romance of the Microscope The Amazing Story of How Fate, Three Men, and a Hobby ‘Discovered the Cancer Germ By Peter Vischer HE old man was getting along in years. And he hadn’t done any- thing yet. All his life long he had wanted to do something, something that would live through time, something great, monumental, something that would make the name of Gye send forth such a beacon of shining light that even unthinking, careless, hurrying men would remember, halt, and pay homage. There weren’t many years left, he knew that, and it began to look as though his ambition were doomed to go to the grave with him. He had money, old man Gye had, but not much. He didn’t have enough to found a school, or build a hospital, or leave some other legacy worthy to bear his name through the ages. No, he couldn’t do that. And he had no children to turn to, none to carry on in his name. Gye frequently bemoaned his fate, his thwarted ambition, as he hurried from the heart of London and through the railway station at Derbyshire, to his home. So it was on this day, when, as happened every morning and every night, he was accosted with a cheery good day. “ AH, GOOD day, Bullock,” he replied, stopping to chat with the station- master, a young chap, earnest and serious, who also knew the pangs and pains of ambition. Bullock wanted to be a scien- tist, but he was poor, and he had to earn his living at railroading, help support an invalid mother, and use only what he denied himself for the only treasure life seemed to hold for him—books. Be- tween trains this youth studied. They often talked of their ambitions, Gye and Bullock—the old man from whom life was ebbing fast, and the young man whose blood was only beginning to boil. And this they did again for some moments, until the older man, his face lighted with sudden inspi- ration, grasped the younger The Hatter Who Rode a Hobby to Fame J. E. Barnard, London hatter, whose experi- ments with microscopes helped isolate the cancer germ, a problem that had baffled the wisest scientists for at least 6000 years his books, the old man died. And the in- valid mother died of cancer. Young Bill Bullock resigned his job and, taking the name of his patron, as William Ewart Gye set his face toward his future. Before long, Gye (the erstwhile Bul- The Boy Whose Dream Came True Dr. William E. Gye, who started life as William Bullock, ambitious railway porter. He got his chance by taking an old man’s name. Now he has made i* famous by isolating the long sought cancer gerra lock) found the path he was seeking and, as a promising student of medicine was enrolled at Edinburgh University. There he sat under the brilliant Bennett, an expert on cancer, the dread scourge of humanity, which for 6000 known years had defied investigation. Gye began to study this unrelenting disease that had sent his mother to an agonizing death. (;*2 worked hard and long. For a time his labors were interrupted, for war came and every true Briton did his bit. He was attached to an ambulance train and made studies of gas gangrene that were of inestimable scientific value. But this was only an interlude. No sooner was the war over than Gye went back to his cancer studies. Incessantly he worked. For two years he did not rest from his researches except to sleep and eat. Christmas Day saw him hard at work in his laboratory. He made thousands of experi- ments with one aim, the by the arm and gripped it tight with excitement. “IT am not famous, nor will I be,” he said hoarsely. “I have no children. I believe in you. Ihave faith Inyou. Some day you will be famous. I can see that. I will leave you the money I have so that you can pursue your life’s ambition, if you will agree to take the name of Gye.” Andsoit happened. One day, not very much later, while Bullock was still down at the station dividing his that kill human beings. of it in the United States last year. scourge, killing with slow torture, practically hopeless when beyond the reach of surgery. And now, with the isolation of the cancer germ, comes hope that this fearful, mysterious enemy of mankind may be conquered at last. story of this tremendous scientific achievement, as told here, reads like a page from an Arabian Night’s tale. Brings Hope to Thousands ANCER, spreading rapidly, has been threatening recently to take first place in the list of diseases Nearly 100,000 persons died It is a Mr. Vischer’s isolation of the cancer virus. Many times when success seemed only a step ahead, he was compelled to begin all over again. Finally he came up against a stone wall. He was satisfied that cancer is caused by a germ that enters the body from without, but he was unable to isolate the germ. He tried filtration, but the germs were so small they could not be taken out of a liquid by the finest filter. He triei catching horrible time between his duties and them under a microscope,

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14 but the finest microscope he had ever heard of—instruments that magnified 1500 times—would not reveal them. Gye was stumped. Now, as so often happens in life, chance enters. The long arm of coincidence, so much longer in real life than any fictionist would dare make it, begins to reach out. It happened that a hatter in Jermyn Street, one J. E. Barnard, head of the firm of William Barnard & Sons, Hatters, had a hobby. By all the rote of successful business life and the usual aspirations of a shopkeeper, he was as mad a hatter as the hatter Alice metin Wonderland. Instead of hurrying to a golf:course when the day’s work was done, or to a card club, or to the races—which anybody could have told him was the proper thing for a hatter with an income to do—he went home and amused himself with microscopes. FTER a while Barnard, the hatter, be- came known among British scien- tists as a willing amateur who knew more than a little about lenses. Then Barnard, the hatter, came to’ be known among British scientists as the man who knew more about lenses than any one in the British Isles. The British Medical Re- search Council started its great: cancer research at Hampstead and nearly every day Barnard, the hatter, after his new stock of bowlers had been arranged and the day’s receipts had been counted up, hied himself to the Hampstead labora- tories to experiment with new lights for microscopy that might impress on a photo- graphic plate things invisible to the eye. By ordinary light rays, about 550 mil- lionths of a millimeter in length, magnifi- cation 1500 times is possible. But Bar- nard knew that by shorter light rays, by ultra-violet rays only 275 millionths long, he would be able to magnify 3000 times, even though he wouldn’t be able to see the result. So he experimented with the in- vention of a group of German scientists at Jena, first announced in 1904, by which lenses of pure quartz were used instead of glass. The ultra-violet light was pro- vided by an electric spark’s jumping be- tween two little points of cadmium. And photographic plates were used to catch the invisible light coming up through the lenses with the picture. {* WAS inevitable that Gye, the one- time railway porter with an ambition, should some day meet Barnard, the hatter with a hobby. When Gye confided to friends that he could go no further with his researches unless he could find a more powerful microscope, it was only a mat- ter of time until some one would say to him that he would have to meet Barnard. The two met. “T’ve got to catch these viruses under a microscope if my experiments are to suc- ceed,”’ said Gye to Barnard. ‘‘Can you do it for me?”’ “T’ll try,” said Barnard. The two worked together steadily and patiently. Gye was constantly at it. Barnard hurried over from Jermyn Street just as soon as his business would free him. Together they conducted countless experiments. They hoped in time to get a picture of 50,000 or perhaps even 100,- 000 of the cancer germs ina group. That would have been an _ unprecedented achievement, for it would have made POPULAR SCIENCE MONTHLY theory into fact and would have provided a foundation from which to fight and eventually defeat one of the three worst of earth’s scourges. They worked quietly and unostenta- tiously. Time and again cures for cancer have been announced and time and again the hearts of men and women have been buoyed up with hope, then cruelly twisted, because the report of a cure was false. Gye and Barnard wanted to make no such mistake. Furthermore, knew that with the isolation of the virus the battle would be only half won. A cure must be found later. So they kept at it. And finally, one Cancer Tests with Chicks Doctor Gye inoculating a young chick with the cancer virus. His experiments showed that the cancer germ produced a malignant growth only when introduced into the victim with germ-free extracts of tumors day, Barnard, with quivering hand, turned over to Gye a microphotograph. Gye took it and held it to the light. There was something never before seen by man, something that no eye could ever see, even with the most powerful microscopes—a photograph of a single round organism en- ticed into visibility by rays of light too thin for sight to catch. Not 50,000 ina conglommerate mass, mind you, but a single round cell—a cancer germ! “T think we’ve got it this time,” said Gye to Barnard. And the two hurried on with their work. GoME weeks later a crowd gathered in a street outside the office of the Lancet, an English medical journal. At first it was just such an indescribable gathering as happens hundreds of times a day, for no particular reason, in New York, or Chicago, or San Francisco. But this crowd swelled minute by minute, until it bulged through the Strand and disrupted the normal traffic of the street. It was not a joyous crowd, nor yet an angry one, nor yet one merely inquisitive. It was quiet and patient, throbbing with a deep excitement. The event that drew the great crowd they - October, 1925 was an announcement by the Lancet that the germ of cancer had been isolated by Dr. W. E. Gye, once a railway porter, and J. E. Barnard, a prosperous hatter. While the announcement made it plain that the discovery was in no way a cure for cancer yet it was hailed instantly by scientist, throughout the world as one of the greatest medical achievements in history, For in tracing the cause of cancer tog germ, the discoverers laid barea mystery that has baffled physicians for gener. tions. By providing definite knowledge, they paved the way for direct attack on this most dreaded scourge. And they gave science effective new weapons for striking at the root of other diseases, | Scientists point out that, as with other diseases, the discovery of the catige is just the beginning in the fight t wipe out cancer. How soon it can be conquered, no one can say. In the cage of malaria, for example, the enemy went down easily, once it had been located, Research workers gradually discovered that malaria was caused by a germ intro- duced into the blood by a certain type of mosquito. They knew, therefore, that if the mosquito could be prevented from biting men, malaria could be prevented, Other scientists took up the fight, attack- ing the mosquito in its breeding-groundg and making malarial districts healthy. In the case of diabetes the fight wag more stubborn, yet a cure was found at last in the discovery of insulin. But in the war against tuberculosis, although the position of the enemy long has been known, and although its death toll has been greatly lessened, today there is no known cure other than that of strengthen- ing the body to resist the germs’ attack, In discovering the cancer germ Gye and Barnard reconciled two hitherto conflict ing theories of cancer. One theory, com- monly held by authorities, was that the disease was due to some change in the body by which unhealthy cells at a bruised — point were converted into malignant cells. The other was that cancer was due toa germ entering the body from without. In experiments with chickens, rats, and mice, Doctor Gye found that both theories” were right—that cancer is caused by a germ, but that the germ is able to grow only in unhealthy cells. ks ‘THis fact Doctor Gye demonstrated by inoculation of mice. Introduced by it self, the cancer germ was powerless, he found. Only by introducing both the germ and germ-free extracts of tumors was he able to grow cancers in mice. With the cancer germ isolated, Doctor Gye and his colleagues in the British Medical Research Council now are busy with experiments to develop a cancer vaccine that will make it impossible for the germ to secure a foothold in the body. In the Hampstead laboratories, definite success has been reported in making chickens, rats, and mice immune to the disease by inoculating them with a serum made from the newly discovered virus. The perfection of human inoculation against cancer, of course, will not be @ cure for the disease already contracted, yet scientists hold out the hope that soon it may furnish the basis for a preventive campaign to eradicate this curse of man from the face of the earth.

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tober, 1925 .ancet that solated by porter, and cer. While in that the for Cancer, ’ Sclentistg ne of the in history, cancer tog ea mystery or gener. knowl attack on And they eapons for diseases, - » aS with f the catise e fight to it can be In the cage nemy went located, discovered germ intro- ain type of fore, that if ented from prevented, tht, attack- ng-grounds healthy. e fight was was found sulin. But s, although 1g has been ath toll hag there is no strengthen- ‘ms’ attack, rm Gye and rto conflict heory, com- as that the ange in the at a bruised — ignant cells,” as due toa 1s, rats, and oth theories aused by a ble to grow A Bey mstrated by duced by it- ywerless, he y both the ; of tumors rs in mice. ted, Doctor the British yw are busy p a cancer possible for in the body. ies, definite in making nune to the vith a serum red virus. inoculation ill not be @ contracted, pe that soon 1 preventive urse of man AIRPLANE fee” AIRPLANE WITH WINGS IN RELEASE FOLDED POSITION POPULAR SCIENCE MONTHLY 15 Giant Mother of Airplanes Dirigible to Act as a Hangar for Fleet of Smaller Craft AIRPLANE RELEASE CHAMBER in England. be built—a dirigible far larger than our own Shenandoah—to carry a small fleet of airplanes. gram below, at least three-fourths of the great ship is to be used for hangars. The executive officer of the dirigible receives a radio message, asking for a NE of the most daring ideas in aeronautics recently was proposed It is that a dirigible shall plane to call at some outlying post or town. A plane is wheeled out into the central runway until it reaches the release chamber, and with a slight pause for adjustment of engine and wings, she hops off. Returning, the plane lands on the broad, flat top deck of the dirigible, is received by the elevator and restored to the hangar deck, where it is entirely overhauled. As shown in the dia- LANDING DECK Cut-away view, showing interior of the giant dirigible that will carry small airplanes for scouting or mail service

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16 POPULAR SCIENCE MONTHLY OUDINI-4 October, 1925 Houdini in his study, sur- rounded by his books, preparing his remarkable series of arti- cles which begins in our next number many times. I saw him first 20 years or more ago, when he was known as the ‘“‘Handcuff King,’”’ and was exhibiting his astonishing ability to escape from shackles, ropes, chains, strait- jackets, locked trunks, and a variety of other bonds and entanglements. I had seen him in more recent years cause a five-ton elephant to disappear from the stage. I had seen him shackled and thrust head first into a metal cylinder filled with water, over which a tight- fitting cover was padlocked. There seemed no possible escape for him from this dreadful contrivance; yet, only a second, it seemed, after the big can was screened by a curtain, he emerged, dripping and breathless, the shackles in his hand and a smile on his face. I had seen him perform his famous needle trick in which he swallows four or five packages of needles and many yards of thread, and then has a member of the audience pull all from his mouth—with every needle threaded! I had seen his amusing but highly instructive and useful exposure of the tricks of fraudulent spiritualistic mediums. But my greatest surprise from this master conjurer was reserved for a few weeks ago when I visited Houdini at his home in New York City. I found Hou- I HAD seen Houdini on the stage— dini the man a more extraordinary person- age even than Houdini the magician! Houdini the magician—the man known to the public—is a professional trickster, an expert showman; spectacular, theatri- cal, practised in every artifice and device Houdini the of the public entertainer. man, though, is a student and scientist, who prefers his library, stocked with a quarter of a million dollars’ worth of books, on every conceivable subject, to any other place on earth. He is master of six languages, and is versed in the literature produced by the greatest thinkers in all six tongues. He has profound knowledge, both practical and theoretical, of the natural sciences. He handles mechanics’ tools and the deli- cate apparatus of the physical and chemical laboratory with the deftness of a specialist. He is an author, a psy- chologist, an anatomist, an inventor, a brilliant talker, a world traveler. He has known the greatest men of his time and in these contacts has contributed quite as much as he has taken away. He is an athlete, who by training and self- denial has kept to middle life the lithe, powerful body necessary to the per- formance of his amazing feats. He is a business man, whose shrewd investments have made him one of the wealthiest men of the theatrical world. ND it is Houdini the man who domi- nates Houdini the magician. As Hou- dini himself expresses it, ‘‘I could make a fortune every year on the stage—if I wished to.”’ Houdini the man, however, will not permit this. For five months each year Houdini the magician appears before the public; the other seven months belong to Houdini the man. Then it is that Houdini immures himself in his library to read, study, write, and to invent. It may seem surprising that one whose The Most Mysterious m MAN in the WORLD By Raymond J. Brown chief fame has come from dexterity of hand and strength of body should possess so remarkable a passion for pursuits of the mind. Actually, though, there is nothing surprising about it; for Houdini was a scholar and a teacher long before he be came a magician. The son of a clergy- man and educator, he was reared ina scholastic atmosphere, and almost before he was out of knee pants, he taught modern and ancient languages in the school his father conducted in Wisconsin. “Books were my hobby, even as 4 child,’’ he told me. ‘“‘I read almost every book in the Milwaukee Public Library before I was 15. My reading was not systematic. It made no difference to me whether they were fairy tales, textbooks, philosophic essays, poetry, or romantic fiction. Some of the books I didn’t under- stand—but I read them just the same. | believed, you see, that my life work would be teaching, so I wanted to learn everything I could about every possible subject.”’ “It’s rather strange, isn’t it, that a book-lover should take up such af unusual profession as magic?’”’ I sug: gested. “T went into magic more or less sud- denly and by accident,’’ Houdini said. ‘“‘When I was about 15 I was attending 4 magician’s performance with some friends. I hadn’t studied magic particularly at the time; yet I wasn’t mystified at all. Each time the magician would complete 4 trick, I’d tell my friends, ‘I know how he does that,’ and at last they got tired of hearing me say it.. ‘Well, if you’re s0 darned smart,’one of them said,‘why don’t

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dctober, 1925 LD dexterity of ould possess suits of the re is nothing udini was a efore he be- of a clergy- reared in a most before he taught ges in the . Wisconsin. even as 4 Imost every lic Library ng was not rence to me , textbooks, yr romantic idn’t under- he same, | * life work ed to learn ary possible it, that a » such aD 2”? ~T sug: or less sud- yudini said. attending a ome friends. larly at the tall. Each complete 3 now how he rot tired of f you’re 80 ‘why don’t October, 1925 ou go on the stage and do those tricks yourself?’ ‘All right,’ I said; ‘I will.’ And I did. “That was more than 35 years ago,” continued Houdini reminiscently, “and I’ve been at it ever since. I made up my mind at the beginning, though, that if I was going to be a magician, I was going to be a good one. There seemed only one way to make sure of that, and that was by devising my own tricks—tricks that no one had ever seen before. “My habit of reading stood me in good stead. I bought every book on magic that I could find, taught myself to do every trick that was described—and then discarded them all and invented original tricks and constructed with my own hands the apparatus necessary to per- form them. And I’ve been doing that ever since. Every illusion I ever have performed has been conceived, con- structed, and executed by me alone. And not one of them,” he added after a moment, ‘‘ever has been correctly ex- plained. I have performed them before millions of people. I have performed them privately before professional magi- cians; and they are still secrets—mys- teries—known to me alone. “One of the greatest thrills I’ve ever had came when I was a young performer and it was reported to me that Kellar, dean of American magicians, was saying to his interested and puzzled audiences: “ ‘Don’t be ashamed if I mystify you. I have seen POPULAR SCIENCE MONTHLY The Modern Aladdin Never has there been made a pair of hand- cuffs from which Houdini could not quickly escape by his mystifying and skilful magic table, and he thrust the slate beneath it and requested me to take hold of it. An instant later there came a _ scratching sound from under the table. When this ceased, Houdini released his hold on the slate and bade me raise it and look at it. The slate contained my name, home 17 address, and home telephone number, written in chalk! “Mystifying, isn’t it?” inquired Hou- dini, laughing at my expression of aston- ishment. ‘You’d almost believe me, wouldn’t you, if I told you a spirit wrote that? Well, I’m the spirit that did it. “Look here,” he directed, thrusting his hand beneath the table and drawing out a second slate. “This,” he said, “is the slate you saw me bring into the room. The slate you have in your hands was under that table for several hours—mes- sage and all. I wrote that message when you phoned me that you were coming here. It was an easy matter for me to get your home address and telephone number from the directories when I knew your name and occupation. When I asked you to hold the slate with me under the table, I made a ‘switch,’ handing you the pre- pared slate, which I released from a clamp that held it against the under side of the table and placing the blank slate in the clamp. The writing sound you heard I made with my finger nail on the surface of the blank slate. “That, of course, is a very simple trick; yet through it I probably could have convinced you that I was a mind reader, a medium, and what not. Just a moment, and I’ll show you something even more astonishing. Write a message on that blank slate, and let me see it.” The message I wrote was: “Houdini is the most mys- ~ terious man in the world.” Houdini’s work, and I have no idea how he produces his effects.’ ”’ “Do you intend ever to explain how you produce your effects?”’ I ventured. “Certainly,” Houdini an- swered. ‘‘I’ll explain to you right now. I produce my effects by natural, physical means; by utilizing well- known laws of science and mechanics for the purpose of mystifying. I have no occult powers. I can no more tell you what you are thinking about at this mo- ment than I can cause those buildings opposite us to collapse by waving my hand. . “T cannot transfer my * thoughts to another person’s mind except through some recognized form of com- munication. I cannot bring back the spirit of one who has departed. If you were to lock me in this room, I could not escape except by means of a key, violence, or the employment of the purely physical skill I have acquired at escaping from restraint. However, by trickery I can make it ap- pear that I am able to read your mind, to transfer my thoughts, to establish com- munication with the dead and so on.” Houdini excused himself for a moment and returned with a blank slate. We sat at opposite sides of a small of Houdini the man. entist, will tell his own story. experiences NEXT MONTH Houdini’s Own Story Mr. Brown’s article on these pages gives you a living picture ning in our next issue Houdini the magician—the student, sci- and wonder worker— frank, vivid way he will reveal many secrets of the mystic world in which he lives. He will tell some of his dramatic with fraudulent mediums, of surprising ways in which he has exposed trickery. Don’t miss this amazing story of wonder and mystery. This picture shows Houdini, sus- pended, head downward by block and tackle from the top of a skyscraper, freeing himself from a straitjacket “Thanks,”’ smiled Hou- dini as he read it. “I hopeI deserve the compliment. Now turn the slate face down, and don’t let any one see it.” He walked to the door, and called upstairs, request- ing Mrs. Houdini to join us. When she came in, her hus- band presented me to her, the three of us exchanging the polite commonplaces that are customary on such occasions. Not once that I could notice did Houdini make a signal or voice any- thing beyond the conven- tional remarks incidental to introducing a guest in his home to his wife; yet not more than 20 seconds after she had entered the room, Mrs. Houdini turned to me, smiled, and said: “You wrote on that slate, ‘Houdini is the most mys- terious man in the world.’ ” “How on earth did you tell her that?” I demanded of Houdini after his wife had departed. “By natural, physical means,” he replied. ‘Mrs. Houdini and I used to do a mind-reading act, and have a secret code of communica- tion—made up entirely of natural gestures, words, and so on—which permits us to exchange the most compli- cated messages in the pres- ence of others without de- tection. (Continued on page 154) Begin- In his

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U ncle Sam’s POPULAR SCIENCE MONTHLY Lowering Away the Floating Caisson Repair ship standing by U.S. S. McCormick (left) to replace damaged propeller, weighing 6500 pounds. This remarkable feat was performed in the Pacific Ocean by means of a floating caisson and sailor-divers . October, 1925 Cruising Repair Shop Destroyer’s Broken Propeller Ingentously Replaced in Midocean in the Pacific, there was performed on the destroyer McCormick one of the rarest and most difficult operations of modern seamanship—changing a damaged propeller while on the high seas. In 4% hours the old propeller had been removed, a new one put in its place, and the destroyer was ready to proceed on its way... This extraordinary feat was made possible by_a_ special type of caisson in- vented recently by Lieut. William O’Neill at the Philadelphia Navy Yard. Damage to propellers is not in- Dives the recent naval maneuvers weighing about 214 tons, would be de- cidedly in the way on a destroyer. The repair ship draws up alongside the destroyer and lowers the caisson at the stern of the destroyer by means of leading and guy wires. The caisson is about 12 feet deep and long enough to contain the propeller and a short section of the propeller shaft. The submerged caisson slips up under the propeller from the stern and is brought up so that the upper edge is about three feet out of water. The propeller shaft slips halfway down the box in a slot that curves at the bottom to fit the shaft. After the box is in position, a door slides down the slot, filling the opening. The bottom of the door is curved, fitting the upper part of the shaft. A diver then descends into the box and calks the crack between the shaft, caisson, and door, so that the box becomes water- tight. Every destroyer carries diving equipment and at least one or more sea- men gunners trained as divers. Divers are needed to free anchors frequent among the smaller ves- sels of the navy. Constant vibra- tion sometimes causes a propeller to crystallize and throw one of its blades. Or one or more of the blades may be clipped off by strik- ing a submerged rock or bit of wreckage. Even if the blades are not broken, if.one is badly bent, the resulting vibration to the vessel is so tremendous that the destroyer cannot make good speed and the propeller must be re- placed. On both the Atlantic and Pacific oceans there are cruising repair ships for both destroyers and battleships. If one of these hap- pens to be within radio-calling distance, it will bring a new pro- peller and caisson and the work can be done on the open sea. It would be possible for a ship to make its own repairs if it had the equipment, but extra pro- pellers weighing many tons and the caisson needed for the work, How the caisson is adjusted to propeller shaft by a sliding slot that is tightly calked until new propeller is in place or recover torpedoes that have been shot into the mud and that may be used again. The diver passes a line about the latter and they are drawn back to the ship. All the water is pumped out of the caisson, and one or two men re- move the damaged propeller. A nut and locknut hold the propeller on theshaft. These are covered with a pointed cap of light metal. These parts are removed by means of a sledge hammer and iron bar and the propeller is driven off. The weight of the propeller is sup- ported by a line from the repair ship. It is easier to slip the new propeller into place than to remove the damaged one. Some destroyer propellers are not welded in one piece, but have separate blades. In such cases it is necessary only to replace the blades that have been damaged. One of the pro- pellers changed on the McCormick weighed 6500 pounds.

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tober, 1925 t) ic TS - Can eller shaft a slot that the shaft. door slides ning. The fitting the he box and ft, caisson, mes water- ies diving > more sea- as divers. ree anchors that have 1 and that The diver latter and :0 the ship. iped out of [wo men re- eller. Anut ropeller on »vered with etal. These means of a on. bar and off. The ler is sup- the repair >» the new n to remove ie destroyer ded in one ate blades. essary only that have of the pro- McCormick October, 1925 POPULAR SCIENCE MONTHLY 19 Some Snares for Inventors How to Avoid Pitfalls and Protect Your Ideas—W hat a Patent Really Is Clean-Up Week at the Patent Office Arecent ruling of the U. S. Patent Office discontinuing the use of models of inventions resulted in a general housecleaning and sorting of 155,000 models accumulated since 1884. _ Patent Commissioner Thomas P. Robertson is shown above with a few of them By Frank Parker Stockbridge ITH “blood in his eye,’’ a man \ \ walked into the office of a famous patent attorney. His hands in- dicated that he was a mechanic; his cloth- ing, that he had “‘dressed up” for the occasion. “See this advertisement of the sky-high carburetor?’”? he demanded. “I’ve got a patent on that, and I want you to sue ’em for me for a million dollars. Here’s the official copy of my patent—‘June 18, 1920, to John P. Smith.’ I’m Smith.” The attorney studied the advertise- ment, taken from an engineering periodi- cal, which showed a detail drawing of the sky-high carburetor. Then he looked over the patent papers. “Just where do you claim there is an infringement, Mr. Smith?” he asked at last. “Why, in the method of controlling the air supply,” replied his visitor. ‘See the way they show it in their picture? Now, that’s just the way it is in my patent.”’ The attorney studied the patent papers again, but his attention was fixed on the printed text instead of on the drawing. “T don’t find anything in your claims covering this method of air control,’’ he said finally. ‘‘If this is all you have, Mr. Smith, I’m afraid you haven’t much chance to collect that million.” _ Smith turned pale. ‘‘But—but it was In my application, all right,’’ he stam- mered. ‘That’s my whole invention—all these other things are just details. And it shows right there on the drawing. Do you mean to tell me my patent’s no good?” “It’s a good patent, as far as it goes,”’ the attorney answered; “but it doesn’t go farenough. Didn’t your original attorney advise you, that your application had been amended?” “Why, I did have some letters from him, but I don’t remember now what was in them,”’ the visitor admitted. He left, worried, promising to bring all the correspondence. ‘‘What Smith thought he had invented and received a patent for wasn’t what his patent described at all,” said the attorney, telling me of this incident. ‘“‘Among the papers he brought me was a letter from his former attorney, telling him that the claim in the original application covering a method of air control had been dis- allowed by the Patent Office on the ground that it was old: He could use it, if he wanted to, but so could the sky-high people or any other manufacturers of carburetors. It showed on his drawing, because it helped demonstrate the action of his actual inventions, which were pat- entable, but not of any particular commercial value, since the same re- sults could be accomplished more simply in other ways. “Q@ MITH had fallen into one of the pit- falls with which the way of inventors is beset. He did not read his patent claims, but took it for granted that they covered what he thought they covered. In this country a patent covers nothing but what is set forth in the claims allowed, and there is no way to correct a mistake in the claims but to apply for a reissue. In England and on the Continent a court in which the validity of a patent is chal- lenged will take judicial notice of the in- ventor’s intention. ‘‘No matter what you have invented, if it isn’t described in your patent claims, you haven’t got a patent on it.” Failure to recognize this important factor cost Renaud, the French inventor 4 : a * a) ; >| of the automobile gear-shifting mechan. ism now universally used (except on Ford cars), the enormous fortune he could have collected in royalties from American automobile manufacturers. “War good is a patent anyway?” I asked another attorney who had been practising before the Patent Office for 30 years. “If you’ve got a good invention, a patent is a protection—until somebody else proves that he invented it before you did,’’ he said. ‘“‘A patent has been de- scribed as ‘a license to sue and to be sued.’ If your invention is good, somebody else is going to claim that he saw it first. And if he can make that claim good, you’re sunk. ““Most inventors make the mistake of thinking that a patent is a guarantee that their invention is valuable. It isn’t any- thing of the kind. Of every 1000 patents issued, 900 are without commercial value.” “Then what does a patent prove, any- way?” I pursued. “It proves only that the _ specific thing described in the patent claims has not been done or described in that precise way before, so far as the Patent Office experts know or can find out,” was his answer. [- SOMETIMES happens that a valua- ble invention is not patentable because it has been described in print so that any one could do the same thing. That hap- pened when Morgan Robertson, writer of sea stories, applied for a patent on the sub- marine periscope. Mr. Robertson went one day with Lewis Nixon, shipbuilder, who was constructing the first Holand submarines for the navy, to see the new craft. ‘‘We’ve been trying to work out a scheme whereby the captain can see where he is going without coming to the surface,”

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POPULAR SCIENCE MONTHLY (NANNY ral) irre H sitivuui! ernest Ml le Ul The Storehouse for 1,500,000 Ideas Nearly a million and a half patents are con- tained in the vast files of the U. S. Patent Office, which issues about 40,000 annually said Mr. Nixon. Mr. Robertson immedi- ately suggested a telescoping tube with mirrors set at the proper angles, that could be shoved up to the surface when the submarine was submerged—practi- cally the periscope, now an essential part of every submarine’s equipment. “You’ve got it!’”’ Mr. Nixon exclaimed. “T’ll have one made and we’ll get it pat- ented-in your name and we’ll pay you so much for every one made.” OBERTSON saw a fortune coming his way; but at the Patent Office, the ex- aminers turned to a copy of Jules Verne’s “Twenty Thousand Leagues under the Sea,” published years earlier, in which an entirely mythical submarine was equipped with an equally mythical periscope, worked just as Robertson had imagined it. The description was so detailed that the de- vice was obvious, the Patent Office held. The same sort of an objection was raised in the case of the balloon tire patent recently issued to an inventor after balloon tires had been in use for several years and their principle had been discussed in print for years before. In this case, however, the Patent Office held that the invention was not obvious from the articles that had been published; and of course the application had been filed long before the first balloon tire was made. Many inventors have lost fortunes by neglecting to make any records of the dates when the inventions first took shape in their minds. A simple sketch or a brief written description, dated, signed, and witnessed by one or two friends, may establish a claim to priority when some- body else claims to have invented the same thing before the patent application was filed. It is not at all unusual for two or more persons to invent the same thing about the same time. Where two or more persons have applications pending for patents covering the same ground, the one who can produce proof of the earliest date of invention gets the patent. Often, however, after a patent is granted, it is challenged on the ground that the same TI mT A Historic Patent One of the most widely heralded patent suits was that which cost G. B. Selden half a mil- lion dollars and the loss of royalties as the sole inventor of the gasoline ‘‘road engine.” A copy of a renewal of the original Selden patent, with drawings, is pictured above thing was being done in industry before the inventor’s application was filed. Then proof often is not easy to get. gee years ago a man named Smith died in Buffalo, N. Y. He had run a bicycle repair shop in Washington, D.C. His executors sold his business and all the assets were bought by another bicycle dealer named Owen. Included in the property were some patents. These Owen handed to his brother-in-law, a patent attorney, to look into. One of them was apparently a basic patent cov- ering a method of hanging the bicycle crankshaft, the method then used by every American bicycle manufacturer, and still in use. Suit for infringement was brought against some of the leading manufac- turers, and they faced the likelihood of having to pay out a fortune for infringe- ments of a patent, the existence of which they had not known. Then an October, 1925 English mechanic, working in Bogtg came forward with an English fe hanger just like the patented article, ang declared that he had brought it ove from England with him a year before the date of Smith’s patent application. gey. eral of his fellow workmen made affidavits that they had seen the device in Smith’s hands at that time. The manufacturers decided to defend the suits. But Owen and his attorney were not discouraged easily. If they could find Mrs. Smith, she might know when the invention had been made. But Mpg Smith had vanished. A search of the vital statistics in Buffalo resulted in finding that Smith had died at a boarding-houge that had changed hands. The forme landlady was discovered. She remem. bered that when Mr. Smith died, Mrs, Smith’s married sister also lived in the house, It took weeks to trace the married sister. Through her it was learned that Mrs. Smith had gone into a convent at Batavia. But she had the keys to a trunk, in which was found a signed, witnessed drawing of the crank-hanger, dated months earlier than the applica. tion for the patent. But still there was that English device of an even earlier date, if the Boston mechanic’s story was true. Owen’s at- torney suspected that the mechanic was lying. And, on the day when the case came up in court, the manufacturers’ attorneys got a letter from the mechanic admitting that he had falsified the date of his arrival in America by a year and had bribed the other witnesses. The dated drawing proved that Smith had in- vented the device before the first recorded use of it anywhere, and the manufacturers pooled their interests and bought the patent from Owen for $285,000. A still greater fortune may be wait- ing for the inventor of the demount- able automobile rim, now universally used, who lost his evidence of priority and- couldn’t. find it for 16 years. His application was filed in 1907 and his patent granted in 1916. Its validity was questioned because such rims had been in general use for years and there was evi- dence that they had been thought of be- fore 1907. Somewhere, the inventor knew, he had a drawing and description, prop- erly signed and witnessed, dated earlier than that earliest date on which anybody claimed to have any prior evidence, Where it was he could not remember. Without written evidence of prior- ity of invention the inventor could not sue to collect from everybody who had made and used demountable rims since his patent was applied for. Then, a few weeks ago, he found a perfect drawing, properly signed, witnessed, and dated! In contrast to the inventor who loses because his claims are not sufficiently specific, one of the largest amounts ever involved in any litigation of a single patent was lost by the inventor because his claim was too specific! This was the famous Selden patent on the automobile. On the face of it, the Selden patent, issued in 1895, covered any kind of an auto- mobile propelled by a gasoline engine. From 1901 every automobile manufac- (Continued on page 160)

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Ic tober, 1925 in Boston, are crank. article, an ht it por. ' before the tion. Sey. € affidavits In Smith’s Lufacturers — Were not could find when the But Mrs, of the vita] in finding ding-house ‘he former 1e remem. died, Mrs, ved in the ie married arned that -onvent at keys to a a signed, nk-hanger, e applica. lish device che Boston Jwen’s at- schanic was n the case ufacturers’ » mechanic 1 the date , year and es. The ith had in- st recorded ufacturers ought the ). be wait- demount- iniversally iority and: ars. His 7 and his lidity was ad been in e was evi- ght of be- knew, he on, prop- ed earlier 1 anybody evidence, “emember. of prior- ild not sue had made since his on, a few ; drawing, nd dated! who loses ufficiently yunts ever a single yor because is was the utomobile. ent, issued an auto- 1e engine. manufac- October, 1925 POPULAR SCIENCE MONTHLY 21 This Woman Expresses Her Ideas The Family Crest John Held, Jr., designed this sign; Mrs. John made it in iron, and John says it tells the family story By Newton Burke LTHOUGH there may A have been women blacksmiths in the past, it is unlikely that any female Vulcan of bygone days ever succeeded in combining mechanical skill in black- smithing with a well developed artistic sense in just the way this has been accomplished by Mrs. John Held, Jr., of Westport, Conn. Mrs. Held, through her own amazing skill with ham- mer and anvil and with the assistance of her husband, a well-known artist and illus- trator, literally has created a growing business out of noth- ing but ideas and sheet iron. It all began, as do so many commercial enterprises, with a desire for something ap- parently not obtainable in the open market. Mrs. Held decided that there ought to be a sign on the gatepost of their farm. A painted sign would not do. Anybody could have a painted sign. A family consultation was held to settle this important matter, and John Held, Jr., jokingly suggested that since she wanted something different, she might put up an electric sign! “While we were still arguing,’ said Mrs. Held, ‘“‘“Mr. Held handed me a sketch with the remark that it illustrated a true state of affairs, as well as being individualistic. “After considering about every possible way in which a sign could be made,”’ she continued, ‘I decided to try my hand at making it out of one solid piece of iron. My previous experience had been limited to hammering brass and similar light metalwork. The first attempt got messed up so badly, I had to throw it in the scrap pile. The second was almost finished when a misdirected blow of the hammer broke off part of one of the figures. By that time I had acquired sufficient skill to do the work properly, and the third sign was a success. THE sign looked so well that I was encouraged to tackle other jobs, such as that fire screen, the standing lamp beside you, and those door hinges.” with Anvil and Hammer Mrs. John Held, Jr., before Her Sample Board Wife of a widely known artist, Mrs. Held at first wrought articles in iron for the decoration of her home. of her skill at the forge, and thus started a flourishing business Mrs. Held is tall and willowy, so unlike the person I had imagined—a sort of sister to Longfellow’s village blacksmith, “with large and sinewy hands, and the muscles of her brawny arms as strong as iron bands’’—that I had to ask her about it. “Blacksmithing is not so much a matter of muscle as it is of knowing how to apply te the a, ‘| ) wa (7 Spreading \ 7a Chestnut “~~ ve. (7, Tree’’ FY 20 }- aaih 4, \ Mr. Held’s_ con- ception of his wife at work—a twentieth-century version of Long- fellow’s poem, “The Village Blacksmith” Enthusiastic friends told ti Weather-Vane and Sign Examples of ironwork made at Mrs. Held’s forge. Each design is original and each is made by hand what muscle you have in just the right way,” replied Mrs. Held. ‘Of course, if I kept at it steadily, I suppose soon I could pose for one of those muscle-building advertise- ments. “But: you see, I don’t have to do that. At first, when our friends began ask- ing me to make articles that can be made most artistically in wrought iron, I worked ° like a slave, but later I trained assistants to do the work my way.” “So now it has become a regular business?’’ [ prompted. “Ta a way it has,” Mrs. Held answered; ‘‘that is, I have a regular staff of black- smiths, who devote a good part of their time to mak- ing up the gate signs and other things Mr. Held and I have de- signed, but the shop still is an old fash- ioned blacksmith shop, where horses are shod and the usual country blacksmithing jobs take up some of the time. Of course, you understand that the work still is carried on by hand. No modern duplicating machinery is used, and every piece is necessarily just a little bit different from another, even when they both are produced from the same design.” ‘But hand work means high prices, and high prices, I should think, would scare many possible purchasers,” I suggested. “PISHAT’S true, but then you must re- member that our gate signs ought to last for years and years. They are far more durable than signs made of wood and painted in the usual manner. “The fact that they are so extremely durable has brought us a number of orders from towns and cities for signs to mark the intersections of -streets. The kids can shy rocks at them until they wear out their arms without hurting the signs in the least.” Mrs. Held and her assistants can com- plete only about two signsaday. She is content to turn ideas and iron into use- ful and artistic objects, and to make a small profit while doing it.

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i 1 rit eaaanae IPPON OS * waters. 22 Science Tons of Gold, Sunken Treasure, Rich Minerals, Huge Food Stores, and Lakes of Oil Challenge Man world’s surface has never been explored. Hidden mil- lions of mysteries have beckoned to man for centuries from this vast area covered by the waters of the oceans. Now, however, spirited venturers in the fields of science are reading the secrets of the sea. They are finding, not only new methods of locating sunken treasure, but also how to prospect for new resources that can be turned to the use of mankind. One scientist says he has found a way to sift pure gold from the salt As an eager prospector would search among quartz hills, this scientist—Prof. Fritz Haber, of the University of Berlin—literally is following veins of gold, silver, and other precious metals running through the oceans. And in this venture he is enlisting the coopera- tion of the U. S. Bureau of Fish- eries. Gold! Thousands of millions of tons of it carried in the foaming surf that pounds the beach; tossed about in mountainous waves of mid- ocean; hidden in miles of watery depths. Prvrentes “surtace of the O SUCH staggering dream of wealth ever lured the hardy adventurers who staked their lives in the reckless gamble for fortune in the California hills or down the Yukon. It seems unreal, fantastic. It has betn found that water from the Atlantic Ocean contains from -015 to .267 part of gold to each million parts of liquid. Water from certain parts of the ocean con- tains nearly twice as much gold as the lowest grade land gold deposits profitable to operate. Captain F. B. Bassett, hydrographer of the U.S. Navy, is authority for the recent statement that billions of tons of gold are dissolved in ocean waters in a concentra- tion of from half a grain to one grain to every ton of water. This represents about $10 worth of gold in every 250 to 500 tons of ocean waters. Will the day come when we shall see great ocean mines where men will dip into miles of sea and extract from vast volumes of its waters the gold it conceals? No one can answer these questions with certainty today. Nevertheless, Pro- fessor Haber’s claims give us some inkling POPULAR SCIENCE MONTHLY Mines the Ocean By Edgar C. Wheeler eRe Fa See rece a How Science Salvages’Treasure An expedition now is working to recover $5,000,000 in gold from the steamship Merida, sunk off Virginia in 1911. Alargeholeis being cut alongside the strong-room, the door of which will be dynamited. Divers wiil load the treasure—weighing about 30 tons—into one-ton wicker baskets, which will be raised by strong pulleys of the fascinating chances of fortune in store for the modern prospector who digs down into mysteries of the unknown deep. The vast expanses of water are satu- rated with valuable salts and minerals. And they literally sre swarming with living things, both plants and animals, far outnumbering the life of the land. Lying beneath these myriad forms of life are great mountain ranges, volcanoes, valleys, and plains that form the floor of the sea. Strewn over this uneven floor, buried in shifting sands and held in the slime of dead things from above, are countless carcasses of wrecked ships that have gone to their doom laden with rich cargoes. Cognizant of these immense possi- October, 1925 Neptune Beckons Hardy Venturers to the Greatest — Test of Human Ingenuity in the World’s History bilities, Uncle Sam’s Navy is em. barking on a far-reaching program of ocean research. As a first step, the U.S.S. Rainbow is being fitted out for an expedition to the Gulf of Mexico and the Caribbean Sea, The announced purposes are to chart the ocean floor and to dis. cover and develop for immediate use some of the sea’s_ hidden resources. OX of the most fascinating efforts of the expedition is to- ward the location of oil fields in the vast realm under the great blanket of water. The navy already has located and charted places in the Gulf of Mexico where oil spots constantly appear. With the oil fields of the land nearing exhaus- tion, the economic importance of such a_ potential discovery is obvious. Scientists have determined by study of land oil fields that the presence of fossils of small shell-like animals, called ‘‘forminifera,” is a highly accurate indication of oil- bearing strata. The Rainbow is equipped to study the geological formation of the sea bottom and to bring up samples of the fossils below the bottom at spots indicated on the charts. The resources sought by the Rainbow include, beside oil and the myriad living things, vast stores of inorganic matter—salts, minerals, chemical elements. Whether the extraction of gold from ocean water by Professor Haber’s process ever will prove commercially practical, there is no question that the sea is a tremendous potential commercial source of common salt, potassium, mage nesium, and calcium salts, iodine, and bromine. A’ THIS moment one of the strangest ships afloat, the Ethyl, is mining the ocean for bromine, an element used in medicine, in photography, and in the manufacture of motor fuel. The Ethyl pumps aboard 7000 gallons of sea water a minute, and from each 1700 gallons is extracted one pound of bromine. Other ships, it is reported, will be equipped similarly to mine this valuable ele ment. Truly, there are fortunes locked in Neptune’s vaults and the number of modern prospectors of the sea is increasing

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Ictober, 1925 AT) Ons Lrers t an he ry avy is em. ng program a first step, being fitted the Gulf of bbean Sea, ses are to and to dis. immediate a’s_ hidden fascinating dition is to. fields in the ‘eat blanket already has aces in the e oil spots ith the oil ing exhaus- portance of scovery is srmined by ls that the all shell-like iifera,” is a tion of oil- Rainbow is e geological ttom and to the fossils ts indicated ht by the > oil and the ast stores of s, minerals, Vhether the ocean water orocess ever y practical, at the sea is commercial ssium, mage iodine, and he strangest ; mining the ent used in and in the The Ethyl sea water a 0 gallons is ine. Other ye equipped luable ele ; locked in number of is increasing

October, 1925

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Mechanical ‘‘Ear’’ to Find Pirates’ Gold William J. Beach, a Canadian, recently perfected a radio device with which he hopes to locate pirate treasure sunk off Cocos Island in the Pacific. Mr. Beach is shown with his instrument and the 26-foot vessel in which he has embarked for the South Seas daily. Probably never before in © history was there a “gold rush’’ so feverish as that which now is luring adventure-loving men away from solid ground. Fortunes are gambled and lives are risked in hazardous attempts to retrieve millions in gold and jewels from the hulks of sunken ships. Wealthy men are spending other fortunes equipping expeditions to study the teeming sea life and the luxuriant vegetation miles below the sea’s surface. Still others are searching the waters of the Mediterranean for the riches of cities that we engulfed centuries ago. MABVELOUS diving chambers have been devised to-permit men to work and explore freely under the tremendous pressure in the deep caverns of the ocean. Undersea cameras now are available to record ocean wonders. Ingenious depth- finding apparatus is giving us accurate contour maps of the floor of the ocean. Radio is being employed in attempts to reveal the spots where sunken treasures are hidden. With these elaborate tools, the ocean prospector is finding his field almost limitless. Just remember that five- sevenths of the earth is covered by the oceans and in the oceans are 302 millions of cubic miles of water! In sunken ships alone fabulous rewards beckon the fortune-hunter. Recent in- ventions make this form of prospecting something more than a wild guess and a perilous plunge. Armored diving-suits and working chambers are making it possible to go down far beyond the 200- foot depth, formerly the limit of human endurance. Improved deep-sea pumping apparatus also is making it possible to remove tons of sand with which Neptune holds many a treasure hulk in tight grip, and to wash

- Merida, sunk in collision POPULAR SCIENCE MONTHLY this sand for bits of precious metal, much as miners wash the sands of streams for grains of gold. Within the next 10 years it is pre- dicted, more wealth will be recovered from sunken ships than in all the pre- ceding ages in the world’s history. Perhaps the achievement that did as much as anything to encourage the present stampede of ocean prospectors was the spectacular success of divers in recovering the $30,000,000 cargo of <i gold from the es wreck of the Lau- rentic, sunk by a submarine off the coast of Ireland in 1917. Other ships of: comparatively recentsinking have given up much of their treasure be- cause science has found ways to reach depths never before attempted. Thousands more await the salvager. LONG our own Atlantic Coast lie at least a dozen of these wreckswithstrong- rooms full of gold waiting the first comers. At this moment four young Americans are exploring what is probably the richest of these prizes—the wreck of the Ward liner 23 We have barely touched its natural riches, and we have just begun to dis- cover its hidden wonders, packed in layers upon layers, one farm and feeding ground above another, each level with its own forms of plant and animal life. The immensity of such a vast storehouse staggers our imaginations. HERE again is a compelling challenge. And the challenge is being accepted by science in a manner which, for dra- matic episode and thrilling adventure, rivals any of the gripping tales of fiction. The most fascinating figure in this new drama is William Beebe, curator of ornithology of the New York Zoological Society. In previous issues of POPULAR SCIENCE MONTHLY you have read of his wonderful explorations on barren Gala- pagos Island—the “‘world’s end’’—and of his voyage of discovery into the Sargasso Sea, that ocean wilderness in the Atlantic. Now, having fished from the depths amazing creatures that never before had been seen, he returns home to report his finds and to prepare for new adventure. And for picturesque setting and lively romance, the new adventure promises to surpass anything in deep-sea mining. This is indicated in the recent announce- ment that Harrison Williams, New York financier, has purchased the palatial million-dollar yacht Vanadis (to be re- named the Warrior) and is transforming her into a wide-cruising laboratory from which scientists will plumb the undersea for fresh wonders. Truly the sea still remains the great frontier of the world. On earth the spots that remain undiscovered can be counted on one hand. But the ocean is still mostly mystery—deep, dark, wonderful, rich.

off the Virginia capes in 1911 with gold, silver, copper, and jewels worth from $2,000,000 to $5,- 000,000. Dragging a mile- long iron sweep along the floor of the ocean, the trawlers Foam and Spray located this prize several months ago. And now, using the most modern of armored undersea appa- ratus, divers are at work to recover the treasure. ET tremendous as is sunken wealth, it is actually small compared with the enormous natural resources of the sea in animal and vegetable life and in minerals. Scien- tists have counted more than 19,000 different va- rieties of fishes, some of which, like the menhaden and herring, are caught by the millions each year. Every year we haul mil- lions of dollars’ worth of products from the sea— foods, oils, fertilizers, pearls, Jeather, shells, glue.

New Suit Doubles Diving Depth This strange-looking steel-and-aluminum diving-suit permits a descent of 600 feet—almost twice the distance formerly possible

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POPULAR SCIENCE MONTHLY October, 1925 A Mechanical Doctor for Motor-Carg Listening for Knocks in the Heart of a Car The “doctor” amplifier, through which the man at the right, By Fritz Blocki MECHANICAL doctor for diag- A nosing practically any ailment of an automobile and for detecting any symptom of minor “‘illness’’ to which it is subject, is one of the newest con- tributions of science toward increasing the efficiency and prolonging the life of the motor-car. This remarkable new apparatus, the invention of F. E. Edwards, of Chicago, automatically puts a car through a thorough physical examination with exaci- ing test instruments, to determine the working efficiency of its various parts, much as a physician puts a human patient through exercises and move- ments to test his respiration, tempera- ture, blood pressure, and other indices to his health. Here are a few of the things that the mechanical doctor finds out about a car: Knocks are located; electrical conditions tested; the horsepower is measured as it is delivered to the rear wheels; the amount of friction in the motor, the rear wheels, and the axle determined; the condition of the wristpins, connecting rods, and pistons is ascertained, compres- sion of cylinders measured, and the amount of dilution in the crankcase oil examined. A, DIAGNOSIS” is made as follows: The car is driven on the testing appa- ratus so that the rear wheels rest on two large revolving drums set into the floor of the laboratory. These drums are geared with a device for measuring horsepower, known as a “dynamometer.” The car is put in high speed and the throttle opened wide. Resistance then is thrown against the driving wheels through the dynamometer, thus making the car at the left is holding a special ‘stethoscope connected with a vacuum-tube with head phones, listens for engine knocks “climb” the steepest hills. Then the amount of torque, or pounds of pull exerted by the car on the dynamometer, is measured. Since it is known how much horsepower the motor itself de- velops, any loss of power may be de- termined, after which the trouble is traced and directions given for eliminat- ing it. Any knocks that develop under load are located. Again the dynamometer is used, this Automobile Ills Diagnosed in Remarkable Chicago ‘** Hospital’? time as a motor, to turn over the wheels of the car with its ignition turned off, The amount of torque once more is meas. ured, giving the amount of friction in the rear axle, drive-shaft, and motor. While the horsepower is being tested, gasoline consumption is measured through a flow meter. By using a process pump inserted in the spark-plug hole of each cylinder, and then pushing and pulling by means of exnan. sion and contraction of air, the condition of pistons, wristpins, and connecting rods is determined and piston slap is located, LECTRICAL connections on the generator, starting motor, and bat. tery are checked by connecting them with special meters. Compression in the cylinders is learned by screwing com. pression meters into the cylinders jp place of the spark plugs, then turning over the motor. If gasoline is leaking into the crankcase oil, such leakage ig shown when a sample of oil is distilled to determine the exact amount of dilution, The rear of the car next is jacked up to examine the wheel bearings. The me chanic goes under the car and with a stethoscope listens for undue noise in the transmission and rear axle while the. car is “running.’”’ When the test is finished, a detailed report is given the car-owner. This re port is used as a prescription for getting whatever repairs may be necessary, after which the ‘‘doctor’’ again sees the car. Where Autos Are Tested by the ‘‘Mechanical Doctor’”’ The car is driven on a platform so that the driving wheels rest on revolving drums geared to a dynamometer (left). This measures working horsepower and ‘“‘pull” of the car

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" Aars 1 in tal’? r the wheels turned off, 1ore 1s meag. iction in the stor. elng tes ired chrom serted in the er, and then 1s of expan. he condition necting rods ) is located, 1S on the r, and bat cting them 2ssion in the ewing com. -ylinders in hen turning 2 is leaking | leakage ig ; distilled to of dilution, acked up to, The me. and with a noise in the hile the. car a detailed r. This re for getting ssary, after ; the car, October, 1925 POPULAR SCIENCE MONTHLY In these models based on the recovered bones of prehistoric men of successive ages, science finds evidence of evolution. Left to right: the Java ‘‘ape-man,”’ believed to have lived some 500,000 years ago; the Piltdown man, 375,000 years ago; the Neanderthal man, 25,000 to 50,000 years; and the Cro-Magnon man, 20,000 years Fust Wuart Js Evolution? The Much-Debated Theory of Man’s Origin Explained in a Nutshell—Points of Evidence Offered by Sctence our readers arrived in the Editor’s mail along with a score of other requests of similar nature. It convinced us that there was a real public need for a clear, concise statement of the subject of evolution, which in recent weeks has aroused bitter controversy and To letter on this page from one of gether the collected knowledge of man- kind to show that every animal, every plant, and every piece of matter around us has sprung from a few simple forms, changing through the ages usually from the simple to the complex, and toward greater perfection. In fact, it holds that an instant. It interprets the Biblical story of creation liberally rather than literally. As to just how Nature is believed to carry on her slow processes of evolution —how one form gradually is developed into another; how from a single cell in the sea has come man, the highest widespread discussion. For that and most intricate form of ° reason we asked the director of PoPpULAR SCIENCE MONTHLY’S Information Department to prepare a reply—one_ that would tell in terms. that everybody could understand, just what the evolution theory : is. The reply follows: DEAR Mr. KLINGEUER: In the recent deluge of state- ments about evolution many of them contradictory, some of them misrepresentations, and others colored by passion, it is not surprising that you found it difficult to define the theory. As is often the case, such an over-abundance of explanation and argument has the effect of complicating a subject that actually should be simple. The simplest and most ade- quate definition of evolution I have found consists of just two words—‘‘orderly change.”’ The theory of evolution is simply a Meadville, Pa. A READER asks— HE EDITOR, Popular ScIENCE MONTHLY. Dear Sir: Several of my friends and I dis- cussed evolution the other night. that as a result of all we had read on the sub- ject during the Scopes trial we knew a great deal about it. But when we got down to brass - tacks, no one of us could define the theory of evolution exactly, nor could we state definitely the reasons scientists have for believing in it. Now you may think it remarkable that a group of so-called intelligent people in this day could be so ignorant, but I have made in- quiries and have found a number of others who are in the same boat as ourselves. I am wondering if you will be so good as to refer me to a book that will answer my needs; or perhaps you could spare the time to write me a letter telling us what we want to know. Yours very truly, We all felt J. C. KLINGEUER. creation—science likewise has its theory supported by study and observation. Briefly, the most commonly accepted theory, as first pro- pounded by Charles Darwin in the middle of the nineteenth century, may be summarized as follows: N°? TWO individual plants or animals ever are exactly alike. A small variation in one individual may make him better equipped to cope with his surroundings than others of his kind. In the strenuous competition of life, only the individuals best equipped for the struggle for existence sur- vive; the poorly equipped die out. Those that survive pass their useful characteristic down to succeeding generations by heredity. And so_ through countless generations, by the survival and propagation of theory that our world as it is today and all life upon it, have been developed since the beginning of time by slow, orderly processes of change, and that these changes are continuing. This theory is regarded by present-day scientists as the only adequate scientific explanation of the mysteries of the origin and development of life. It brings to- all life, including man himself, probably developed from a single form—a mere cell. Thus evolution, as a philosophy of change, is directly opposed to the phi- losophy of fixed unchangeability. It con- tradicts the idea of ‘‘special creation’’— that everything on earth was completed in the most fit amid different and ever-changing surroundings, in- dividual variations work to form new species, new families, and new races. So life has progressed slowly from the single cell, through the shellfish, fishes, reptiles, birds, mammals, and finally to man. This theory of how life has evolved is known as “natural selection.” A similar

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26 process, known as “artificial selection,” has been utilized by modern man in the creation of new species of plants and vegetables and in the breeding of horses and cattle. It has been applied to even the rearing of better human families. In recent years certain aspects of the theory of natural selection have been open to serious question. But while scientists have differed as to the how of evolution, they are practically as one in maintaining that the historical fact of evolution is supported by increasing and over- whelming evidence. The main points of evidence they submit are these: l There are many definite in- ¢ dications thatall animals, man in- cluded, are akin; that all were evolved from the same ancestor far back in the dim ages. The structure of all animals, including man, follows the same general plan. All have similar organs, such as brain, heart, and lungs, performing similar functions. Man’s skeleton can be compared, bone for bone, with that of a horse, a monkey, a seal, or a bat. His limbs have their counterparts in the fins of a fish or the wings of a bird. His muscles correspond with those of other mammals. This similarity extends also to the senses, emotions, and instincts. Men and the animals have the same five senses and similar sense organs. They show the same emotional reac- tions, such as fear, jealousy, and anger. They also suffer similar diseases and are affected in much the same way by drugs and stimulants. The animals that most closely resemble man, and consequently appear to be of closest kinship, are the apes, particularly the orang- outang, the gorilla, and the chim- panzee. Yet scientists never have contended that man is descended from the apes or monkeys. What they do suggest, and what research has tended to substantiate, is their common ancestry, probably in a little tree-dwelling animal resembling the lemur. ? The history of life on earth as ¢ read by geologists in the rocks. Fossils found in successive layers of the earth’s crustshowthat the lowest, simplest forms of life came first. In layers where sediment of ancient sea and lake bottoms were raised by earth up- heavals to form land, scientists have read the story of creation. In the very oldest rocks there are no fossils, indicating an age before life began. Above these, in the stratum formed at a later period, are evidences of the beginning of life—the shellfish. Then, in successive layers, each representing formations of countless mil- lions of years, are found the age of fishes, then the age of coal plants and of frogs, then the age of giant cold-blooded reptiles that dominated sea and land, and finally the mammals, the lowest orders first, fol- lowed by higher and higher development, until finally man emerges. In the rocks, too, has been read part of the fascinating development of man. Scientists have discovered bones of at least seven distinct types of primitive men who lived on earth thousands of years POPULAR SCIENCE MONTHLY before the dawn of history. The picture on page 25, showing the reconstruction of four of these prehistoric men in the order of the ages in which they lived— the pithecanthropus, or famous ‘“ape- man” of Java, the Piltdown man, the Neanderthal man, and the Cro-Magnon man— illustrates the striking comparative evidence of how man has evolved. Scien- tists point to the fact that the more ancient the type, the closer the resem- Man and Horse The fact that man’s skeleton can be com- pared, bone for bone, with that of other animals, is offered as evidence that all ani- mals, including man, were evolved from the same ancestry. Here is a comparison between the skeletons of man and a $ prancing horse blancetotheape. Measurementsand com- parisons of skull and brain have convinced them of a definite development from lower to higher intelligence. 3 Corroboration in the life history of * theindividual. Thelife history of every man and animal is but a short, spectacular repetition of the story of the evolution of man from the simplest forms, as told in the rocks. The beginning of each one of us is a single cell, which multiplies. Before birth, the human infant resembles in turn a fish, an amphibian, a primitive reptile, a primitive mammal, an ape. At one stage he has gill slits; at another, he has a well-defined tail. Until the last three months before birth he has dark soft hair covering the entire body except the palms of the hands and the soles of the feet. Occasionally a child is born with a primitive tail still external. Only Oc tober, 1925 in its last stages of development does th human embryo differ marked] ; of the ape. 7 And even after birth the hum still continues to develop in a closely parallels the scientific t garding the development of the Trace. Ag soon as it begins to use its limbs it starts life as a quadruped, and later makes awk. ward attempts to stand erect. Its lan. guage at first is strange noises. Also scientists call attention to the fact that the normal child, when begin. ning to play, evidences an unmistak. able instinct for cave-digging and tree-climbing, and engages in other sports that resemble closely the activities of prehistoric man. an child Way that heory re. 4 Further corroboration in the * bodilystructureand equipmentof man. In the human body we find an amazing number of muscles and organs—nearly 200 of them—which are useless or practically useless to us, but which still serve important functions in lower animal life. These are called “‘rudiments”’ or “vestiges” —incomplete parts that have been arrested in development. Such are the muscles for wiggling the ears and those for causing the hair to stand on end. Then there is the vermiform appendix, which not only is useless, but often dangerous. It is believed to be a vestige of a time when our ancestors were grass-eaters; in grass- eating animals this organ plays an important part in digestion. The scanty, downy hair that covers the human body, the practi- cally worthless molar teeth that come comparatively late in life and decay quickly, the dwindling little toe bereft of one of its joints— these, according to science, are other common rudimentary reminders of our ancestry. And each of us carries about with him the rudimentary bones of a tail! Higher animals, other than man, also carry similar re minders of possible humbler origin. The splint bones in the horse’s leg, for example, are explained as vestiges of toes that once were useful when he was a little three-toed animal. 5 New kinds of plants and animals ¢ actually are originating and de veloping today. Continually natural- ists are observing how variations in an individual reappear in’ successive gen- erations. Thomas H. Morgan of Columbia Univer- sity says he has observed scores of new forms of fruit fly that never before existed. Similar creations of new species within the span of a few years are reported to have been observed among land snails that live in forests and jungles of many islands of the South Seas. Another interesting example is the tomato. Not many years ago tomatoes were called “love apples,” believed to be poisonous. They were scarcely fit to eat —mostly juice and seeds. Today a dozen luscious varieties of varying shades and sizes have been developed from them. Again, the potato in its first known (Continued on page 150) From one kind of plant or animal they see new kinds produced: Within the last 10 years, for example,

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ctober, 1925 it does the from that Man child | Way that theory te. > Trace, 8 it start lakes awk. Its lan. ses, 0 the fact hen begin. unmistak. Being and S in other osely the in. n in the uipmentof we find an scles and m—which useless to important ife. These “vestiges” have been Such are 1e ears and 0 stand on vermiform is useless, is believed when our 3; in grass. | plays an a hair that the practi. eeth that e in life dwindling ts joints— , are other ninders of f us carries - dimentary mals, other imilar re- ler origin. .orse’s leg, as vestiges ul when he nal. nd animals 1g and de ly natural- ‘ions in an ssive gen- ' plant or produced, — r example, — ia Univer- res of new ore existed. ‘ies within eported to . and snails s of many le is the . tomatoes eved to be y fit to eat ay a dozen hades and ‘om them. ‘st known October, 1925 POPULAR SCIENCE MONTHLY 27 Qur Unseen Foes in the Air How Nature Protects Us Against Millions of Dust Particles that Invade Our Bodies By Newton Burke HERE are many queer things in the air we breathe; most of them ‘ dangerous, many. of them a real menace to life and health. Especially is this true of cities, where factories, hurry- ing crowds, and rushing vehicles all contribute to the invisible enemies that attack us as we drink in the oxygen es- sential to life. These unseen foes, recent scientific re- search shows, ride on dust particles stirred up by the feet of pedestrians and the wheels of traffic. The average person in- hales about 30 cubic inches of air each time he breathes, in which there are likely to be between a half-million and a million particles of dust carrying such dangerous components as— Germs of many diseases, tuberculosis. Garbage, pollen, leaf dust, and other vegetable matter. Steel and other metal particles from factories, car tracks, and the moving parts of motor vehicles. Soot and dust from factory smokestacks. Insect eggs and fragments of insect bodies. Poison gases from industrial furnaces and, probably the deadliest menace of all, carbon monoxide from the exhaust pipes of motor vehicles. The only reason we can withstand the ravages of our unseen enemies of the air is that we have been provided with a marvelous mechanism for repelling their attacks. Most of the germs in the air do including us no harm because they are dried out. This is true of germs of typhoid, diphtheria, and tuberculosis. Moreover, no germ, even if harmful, can in- jure us until it gets into the blood, and formi- dable barriers have been set up to prevent this. The mucous membrane in the nose and throat trap solid particles such as steel slivers, sand, and soot. Thousands of delicate hairs in the lining of the windpipe and bronchial tubes catch stray particles, while at the root of the we Se aie a Shy . lungs are lymph filters. Particles and germs getting beyond these first lines find waiting a powerful army of about 35 billion red corpuscles in the body, each capable of choosing what it will deliver to the body cells and what it will dump as garbage. Then, swarming in the blood are phago- cytes, hollow cells that devour microbes. Finally come the leucocytes, white cells that destroy harmful bacteria and waste material. A disease germ has little chance against this formidable array. Science now is turning its attention The New York laboratory where samples of street air are analyzed and studied in an effort to conquer the invisible foes of health Sanitary inspectors taking samples of air from New York City streets to determine the actual danger to human beings from carbon-monoxide gas discharged from thousands of motor-cars to the gases; for evidently nature did not forsee automobiles and provided no safeguards against carbon monoxide poi- son they produce. This poison is admit- ted into the blood as readily as oxygen. Slightly more than a quart of carbon monoxide is enough to kill a person, and the average automobile, according to tests made recently by the United States Bureau of Mines, produces up to two cubic feet of it a minute. A man can just tolerate four parts of carbon monoxide in 10,000 parts of air. Six parts produce headache, and one per cent might cause death if the exposure were prolonged. Vapors from an auto- mobile exhaust sometimes . contain as much as 10 per cent carbon monoxide. New York City recent- ly began an investigation to determine just how dangerous carbon monox- ide on city streets is to public health. With oddly shaped glass tubes and a small suction pump, scien- tists have taken samples of air from street corners where traffic is greatest. These samples are passed through an appa- ratus that separates the air into its various parts. Various chemicals absorb impurities and gases until finally only car- bon monoxide is left. This is changed by heat into carbon dioxide and free iodine. By measuring the ‘iodine liberated, the investigators can tell the quantity of monoxide originally in the air.

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( an Man Reproduce the Sun? Dazzling Experiments Convince French Wizard that Science May Rival Nature’s Vast Power Supply By Frederic M. Delano POPULAR SCIENCE MONTHLY October, 1925, How Man-Made Sun May Appear Our artist has pictured here the possible sun- producing plant of the future, as prophesied by Prof. Jean Perrin, famous French electrical wizard. Simply by throwing a switch, the operator releases millions of volts of direct current. Between tower- ing giant electrodes there leaps a blinding bolt that builds up into a mighty orb of incandescent fire as the electric current blasts atomic structure. Some of the vast energy released and captured would be transmitted in the form of electricity to run fac- tories and trains or to provide light and heat for the electrodes of a giant electric machine, the mighty arc of blue- white flame dazzled my eyes with its awful intensity. A terrific crackling roar smote the quiet of the laboratory. My senses reeled before this revelation of almost unimaginable power. Professor Jean Perrin, white-haired, white-bearded, benevolent-faced, opened a switch with a long-fingered white hand. The dazzling glare was snuffed out. The crackling ceased. In the sudden quiet even his low-pitched, pleasant voice sounded loud. “It is but the beginning,” he said. “Soon I shall have available a means of producing 10,000,000 volts of direct- current electricity. Then, perhaps, I shall EAPING across the gap between be able to reproduce, on a small scale, the conditions that cause the radiation of light and heat from the sun and the still more gigantic stars of the universe!” I gazed at him in amazement, scarcely comprehending the significance of his words. Was this man actually voicing the hope that he might rival Nature itself? Usurp the power that drives the universe? It seemed incredible. And ‘yet, I re- called, it was no crack-brained zealot talking, but a noted scientist, whose opin- ions are respected by scientists the world over. Head of the laboratory of physical chemistry of the famous University of Paris, member of the French Institute— it would be difficult to find another who occupies a more stable position in the great communities, in place of coal and oil world of science and practical research, “But, Professor Perrin,’’ I questioned, my eyes still dazzled by that blinding flash, ‘‘is what you say to be taken liter- ally—do you actually hope to produce al artificial sun?” “On a small scale—yes,” he replied calmly. ‘What you have just seen is the beginning of the process. When lI have a machine of sufficient power, I can complete it. For with 10,000,000 voltsof direct-current electricity, I believe I cai break up the atomic structure of matter —disintegrate individual atoms; perhaps even drive the nucleus of one atom int another atom and thus create a mudh denser atom. If I am able to do that, the secret of the sun’s radiation will have been solved. “TY BELIEVE,” he continued, “that the sun is formed by the constant chang ing of the extremely light atoms of hy drogen into atoms of greater density, such as atoms of oxygen, nitrogen, the other heavier elements. According t my theory—and many other scientist agree with that theory—everything in the universe—the sun, the stars, the planets, and everything on them—once consisted

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October, 1925, In? nch tval bp ly \ppear ssible sun- phesied by ical wizard. tor releases veen tower- ig bolt that cent fire as re. Some of | would be to run fac- id heat for 1 and oil of hydrogen, and these have et gradually into heavier atoms that make up our atmosphere, our soil, our rocks, our own bodies. “Nearly all scientists now agree that atoms themselves are composed of posi- tive nuclei and negative electrons. Each positive nucleus and the negative elec- trons that rotate around it form, it is be- lieved, an infinitesimally small solar system; so small, in fact, that billions of these complete solar systems in miniature are required to make up the visible ma- terial that composes the point of an ordinary pin, for instance. “ATOMS, vf course, are so exceedingly minute that it is almost impossible for us to conceive a satisfactory picture of them. The number of atoms of oxygen and hydrogen in an ordinary pail of water undoubtedly exceeds the number of grains of sand that would be contained in a peach 50 feet wide, encircling the entire continent of Europe. “Tt is difficult, too, to form in our minds a definite picture of the structure of the atom. For example, scientists believe that if an atom were as large as the city of Paris, the nucleus would be about the size of a block of houses, while each elec- tron, whirling about at a rate between 2000 and 93,000 miles a second, would be approximately as large as a taxicab. “Now the only difference between various kinds of material, such as air or wood or steel, lies in the numbers of electrons that revolve about each of the nuclei that make up the material. “In changing into any other element, I believe that hydrogen changes first into helium, which, you will recall, was found in the sun before it was found on earth. In doing so, a portion of its atomic weight is lost, and given off as energy. This re- leased energy comes to us from the sun in the form of light and heat, and makes life possible on the earth. “How did this process of constant change get started? Probably the colli- sion of two or more hydrogen atoms, or groups of atoms, produced the first energy. POPULAR SCIENCE MONTHLY 29 be built. Eventually we shall have one capable of producing 10,000,000 volts. Then we can proceed with our work.” I pondered over what he had told me, and immediately the thought occurred— suppose he succeeded in accomplishing his astounding plan. What would that mean to our world? If the series of atomic changes he described had spread like wildfire on the sun, how could we He Hopes to Biast the Atom Prof. Jean Perrin, head of the physical chem- istry laboratory of the famous University of Paris, who says that soon he will have the means of producing 10,000,000 volts of direct- current electricity. With this he expects to reproduce on a small scale the conditions that cause radiation of light and heat from the sun stant reaction that, by always creating heavier atoms from those of minimum density, produces the sun’s heat. t “By hurling against the atomic struc- ture 10,000,000 volts of electricity, I may be able to produce this change of light atoms into heavier atoms, and thus, in effect, create another sun.”’ I recalled to Professor Perrin that the late Doctor Steinmetz and his co-workers in America already had produced in the laboratory thunderbolts of a million and two million volts. “FTAHAT is quite true,’”’ Professor Perrin explained. “But he was working along different lines and he used alternat- ing current. To break up the atom, one must have direct current so that a definite potential, either positive or negative, can be applied to the atoms you are trying to disintegrate. ‘Hitherto the greatest direct-current voltage obtainable was between 250,000 and 300,000. My machine, however, know that the same thing would not hap- pen on earth were man to reproduce artificially the conditions that created the sun? Would it not break up the entire atomic structure of the universe? Would it not cause our world to burst into flames and burn us all into cinders in the twinkling of an eye? I ASKED Professor Perrin these ques- tions. He replied with a Gallic shrug of his shoulders. ‘Disaster,’ he admitted in his quiet voice, ‘“‘is a possible conse- quence of smashing an atom. But it is the duty of the true scientist to investi- gate all phenomena. It is only in that way that we may learn. We must not be afraid.” Then a smile curved the lips of the white-bearded scientist. ‘‘But disaster is highly improbable,’”’ he added, “and the possibility of disaster is outweighed by the tremendously useful possibilities con- tained in the process I have in mind. Consider: Our civilization is built on machinery; that would be useless without power to run it. Our supplies of coal and oil will not last forever. There is only a limited quantity in the earth and when that is exhausted by future genera- tions, there can be but one result—stagna- tion, starvation, disaster—unless before our supplies of natural fuels are exhausted, science finds some new source of power and learns how to use it. Perhaps it will be the power generated by the disintegra- tion of atoms that will make possible the saving of our civilization from annihila- tion.” 7 And then Professor Perrin outlined for me a vivid, convincing picture of the tremendous power-producing plant of the cal research, - questioned, hat blinding » taken liter. o produce an As a little match will set fire to a great forest, so this collision set going the con- delivers almost 600,000 volts. Greater future—the plant in which scientists may direct-current generators undoubtedly will (Continued on page 152) ’ he replied just seen is ss. When I power, I can ),000 volts of yelieve I cai re of matter ms; perhaps 1e atom into ate a much » do that, the rill have been ed, “that the stant chang atoms of hy- iter density, ‘itrogen, and According to er scientists ything in the Le . * _ the planets, : PATE TI ' isted | Professor Perrin’s new 600,000-volt direct-current machine in Paris, with which he is conducting experiments that he hopes will lead ace consis to the disintegration of the atom. Hitherto the greatest direct-current voltage obtainable was between 250,000 and 300,000 volts

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An Ice-Locked Island of Mystery HE gleaming beauties of a strange bar- ren island of eternal ice that lies in the Antarctic Ocean south of Cape Horn are re- vealed to the world for the first time in these remarkable photographs recéntly taken by Captain Frank Hurley, famous explorer and photographer. The land is called “Elephant Island,’’ and it is one of 12 islands in the South Shetland group that are entirely de- void of vegetation. Here Captain Hurley and party spent eight months of exploration POPULAR SCIENCE MONTHLY October, 1995 A Land of Gleaming White Mountains, forests, ravines, and caverns, all carved by nature in perpetual ice, make Elephant Island a place of fascinating mystery. Members of Hurley’s explor- ation party are seen above digging a tunnel leading to a vast ice cave. At the left is an iceberg towering in the form of a giant helmet off the shore of the island pat In the frozen wilderness. At the left one of the explorers is seen making his way through the ice forests of the island. The picture at the right shows another member of the party looking into a deep abyss from a cliff of one of the mountains of ice

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ec ‘arved by d a place ’s explor- eading to wering in he island of ice 7. R_ suc- cess or failure in a new job often depends on the uestions you ask inadvance about the men and the concern ‘you are to ek for.” POPULAR SCIENCE MONTHLY Municipal employment bureau in New York City, where men usually ask only about hours and pay 00 to Pick a ew Boss Secrets of Getting the Right Start Revealed by Science T THE head of one of the greatest A dry-goods organizations in New York is a man who attributes his success largely to the fact that he once turned down a $25,000-a-year job in favor of one paying $5000! The reason for his astonishing decision was his deep-founded conviction that care in choosing the right kind of boss and the right kind of concern is the most im- portant factor in business suecess—much more important than immediate financial return. In the case of the $5000 job, this man knew the employers to be men of charac- ter and ability—men he would like to work for. Of the $25,000 job he was not so sure. On one hand he saw certain opportunity, steady advancement from a comparatively small beginning; on the other, in spite of the immediate reward, ' the future was at least doubtful. One position offered a chance for active inter- est in the business; the other was just “a job.” Look at the records of men who have attained business success and you will find, I believe, that, in almost every case, at every step along the way, they have studied carefully every prospective job, and have chosen deliberately the bosses they will work for! In recent years scientific methods have been used more and more in reducing business inefficiency. Nowhere has the effect of these methods been more marked than in the selecting of men for jobs. Nearly every one who has applied for a job with a big corporation has met this effort in the form of an “application.” By Samuel S. Board R. BOARD is a leading authority on the new science of job-getting, known as vocational guidance. The advice he gives here is based on his actual: experience as Vocational Di- rector of the Central Branch, Young Men’s Christian Association, Brook- lyn, N. Y., where he has aided hun- dreds of men to fit themselves to the right job.—_THE EDITOR. And just as it is important for the employer to know what kind of man he is hiring, so it is as important, or even more so, for the employee to know certain definite facts about the men and the concern he is to work for. Success or failure may hang on that knowledge. Most employers whose salesmen handle money demand a bond. Yet I know of more than one good salesman who has tied up with a concern, risking both his good name and his trade repute, without anything but a perfunctory inquiry as to the firm’s financial reliability. And when it has gone bankrupt in. two or three months, he never has blamed himself. A typical example of the really tragic results that often come from this lack of scientific care in job-getting recently came tomy notice. A young office mana- ger with good prospects in a New York wholesale house decided that the field in which he worked was restricted. He answered a Chicago firm’s advertisement. After a few perfunctory inquiries he _ you in a few minutes.” agreed to go to Chicago. Upon reporting for work, he discovered that not only was his immediate superior ‘‘a crotchety old maid,”’ but also that the firm was shaky financially. When the company went on the rocks a few months later, more than one of his acquaintances said, “Why, if only you had asked me, I could have told you they were on the toboggan. I sup- posed you knew when you took the chance.” Simply because he failed to ask a few vital questions about his employers, he found himself out of a job at. the worst possible time of year. The average ‘man, particularly the young man, doesn’t ask very many questions when he is interviewing a prospective employer. He usually just sits and listens, although he can be de- pended on ordinarily to find out what the pay is, what the hours are, what depart- ment he is to work in, the name of his job (if it has one), and when he will start to work if hired. HERE are, however, other items just as essential if less obvious. In fact, it is just as possible for you to use an appli- cation in picking a new bess as it is for an employer to use an application when he is hiring you. Of course, you can’t go to Mr. Smith of Smith and Jones, and say, ‘“‘Now, Mr. Smith, here’s an application for my services that I should like to have you fill out, and if it is satisfactory, I’ll interview But there are certain essential facts you can seek every time you apply for work. You can jot them down on paper before you interview

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32 POPULAR SCIENCE MONTHLY October, 1995 an employer, and then make a conscious effort to obtain the information from him. Is the position permanent or temporary? What are the qualifications for the job? Under whom will you work? In what surroundings? To what higher position would the job under consideration lead? These are a few of the vital points any reasonable em- ployer should be willing to He had not thought of this handicap, if he knew about it and the employer had not tried him out. Facts You Ought to Know about the Job N THE following questionnaire Mr. I Board has listed what he says are the essential facts to be sought whenever you apply for a new job. The best way, he says, 1s to study them before you interview an employer, and then make a conscious effort to obtain the information from him: HILE in many large ' companies a physical ey, B amination is a part of the process involved in getting a job, such examinations Usually are conducted only to deter. mine the likelihood of th company’s liability for damage make plain. Others I have embodied in the typical “ap- NS i Soy ickncas ecko Phone......... plication’”’ that accompanies Business (part of what industry or business) .... this article. Many of these ET ir ee ee How paid......... questions may seem obvious, yet it is surprising how often they are forgotten in the ex- citement of getting a job. iid WAS only last June that an enterprising young man obtained a bookkeeper’s job at a summer hotel. Every- thing looked fine until he dis- covered that the proprietors were Austrians, most of the employees were Germans, as were many of the patrons. Knowing nothing of the Ger- man language, he was decided- ly out of place and could not give efficient service. A few eareful inquiries before he Exact name of firm or employer Training and education required and desirable Relationship to rest of organization Work starts...... Temporary or permanent..... Name and characteristics of immediate superior’ .. Type of associates Name and position of interviewer Policies and methods of hiring, firing, and promo- Are they done through— Status of industry as a whole Status and reputation of this firm in industry Financial status tion, including raises. Gepertment?............. 2. Department heads OF SAG OFT... ees 8c) (cr | b. Connections......... Cimpenionty . ......... 1. Education..... oe Si insurance policies. za an effort made to study the es probable effect of the job ong .s man’s health, and almost neve i is the subject considered from ty, Here the question of you 1. Employment fe SER a eer jobs are likely to be, and what Requirements for further progress in work: 2. Personal development... . 3. Experience in the organization ............ in case of accident, or to megt requirements of compensation Seldom jg the standpoint of future job the applicant may be in line for. future is clearly up to yoy when you apply for a job, If you would carefully build your career according to well-arranged scientific plan, it is essential at the outset to find out what your futur they will demand in health, education, and social abilities, . Almost every position has some drawbacks, yet if you made the move would have know the facts and study them saved him time, trouble, and expense, as well as disappointment. Men who have spent years in special- ized training and reputation building should study prospective positions very carefully. They must consider such questions as the general standing and prospects of the industry or occupation, the financial and business standing of the firm, the type of person with whom they will have to do business, both inside and outside of the organization, why the last incumbent of the position left, and whether the demands of the work are within their limits, whether these limits be physical, mental, or social. AST winter a man who had spent sev- eral years studying accountancy, and who had been getting about $3000 a year, confident of his training and ability, came to New York from the South. After some search he took a job with a public accounting firm with the under- standing that, while no definite sum was settled, he would be paid a salary corre- sponding to the work, and would find a permanent berth. When his first weekly pay check came it was $27! He protested, but his protests brought only promises, though he was given work for which other firms were paying $50 and $60 a week. It took him more than three months to find a job elsewhere at a figure near his former salary, and then he stepped out of the first organization just before most of the employees werelaidoff. The firm only wanted his services for the three or four months in question. They hada reputation for “stringing employees along.’’ But the Southerner had neg- lected to make the inquiries necessary to reveal this and he had neglected to pin his employers down to a definite salary and a definite opportunity for advance- ment. Firms with reputations for fairness are particularly careful to have such con- ditions frankly stated. Employee and employer alike com- monly fail to consider the physical limitations of a job. A young man of excellent personality and real ability came in to see me the other day, jubilant over an opportunity with a well known ribbon house where advancement’ was almost certain. Yet a vocational inter- view showed that the young man was afflicted with a special form of color blindness, and that a ribbon house in which he would have to match the most delicate variations of color was the last place in which he could work effectively. This Way Is a Gamble Answering an “ad” and jumping into a job without first finding out the status of the employer and what the job holds for you is likely to result only in disappointment and considerable loss of your time and effort carefully and methodically, you will be surprised how they will help you avoid pitfalls that almost ip evitably confront a man in a new job, A friend of mine recently succeeded a brilliant man. At a luncheon he was introduced by his new chief to other members of the staff with the invitation to “‘say a few words.’’ It so happened that just before the luncheon one of the } men had whispered to him that he should not, under any circumstances, make a speech. So he turned the invitation of with a remark about actions speaking louder than words. Later it developed that his predecessor had antagonized his associates frequently by lecturing them as if they knew little and he knew it all. Thus, any similar tendency on his part might have hampered his work materially. Such seemingly unimportant facts # the personality of a predecessor are @ utmost value. The more we can leam in advance about the character of prot pective employers and associates, the better we can determine ow chance to fit into the scheme sue cessfully. [NFORMATION about the stand- ing of the business as a whole and of one firm in particular sometime is difficult to obtain, but there are trade and technical publications that give summaries of general industrial conditions and the prospects for the future. The ratings given by Dui and Bradstreet may not be available’ for use directly, but unless the firm you seek information about happem to be a client of your bank, the bank usually will be willing to give you 4 fairly definite idea of its standing. Thet too, nearly every man has friends # (Continued on page 170)

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October, 1925 ight of this ew about it, ar had not many | physical ex, part of the In getting a tions usually ly to deter. ood of the for damages +, OF to meet om pensation . Seldom jg o study the the job ong almost never sidered from future jobs y be in line ‘ion of your up to you for a job, refully build ording to a entific plan, che outset to your future be, and what d in health, cial abilities, position has yet if you d study them nethodically, hey will help almost in 1 a new job, succeeded heon he was ief to other he invitation so happened yn one of the hat he should ices, make a invitation of ons speaking it developed tagonized his cturing them e knew it all. y on his part rk materially. tant facts cessor are of we can leam acter of pros d_ associates, etermine out scheme sut ut the stand 's a whole and ar sometime but there are jlications that oral industrial spects for the riven by Dun t be available’ nless the firm ibout happels F ank, the bank » give you ® nding. as friends # 170) October, 1925 POPULAR SCIENCE MONTHLY Light Bullet-Proof Car Designed for Speedy Cross-Country Scouting will future warfare see squadrons of troopers careening over rough ground in automobiles? The U. S. Field Artillery Board re- cently tested a cross-country car, the vehicle that may replace the horse in pattle, at the Aberdeen Proving Grounds in Maryland. After the trials the Board recommended the adoption of the car fer field artillery reconnaissance, finding it superior to caterpillar-tread tractors and to motorcycles for cross-country work. The vehicle, as designed for the Mary- land tests, is a stripped Ford chassis with bucket seats, builton. Itis equipped with palloon tires. An auxiliary transmission permits the low speed of three miles an hour, necessary to accompany marching infantry. The radiator and engine are protected by a bullet-proof shield. A new transmission was added to the regular system, giving two neutrals, six speeds ahead, and three to the rear. Two stabilizers keep the body from bouncing on rough roads or across country. For scouting work the little car has the advantages of greater speed and less vulnerability than horse or mule. Hits on any part of the bodies of animals, excepting the ears and tail, disable them; the car offers far less of a target and a far more resistant one. Poison gas is fatal to animals, but does not affect the internal mechanism of a motor-car. [ eitices of thrilling charges of cavalry, 33 U. S. Army Tests “Flivver Cavalry” The Cross-Country Scout Car Giving from 15 to 20 miles to a gallon of gasoline, this little car is being tested for scouting, artillery, and motor transport work in U. S. Army Which Makes Better Target? The diagram above demonstrates the greater vulnerability of a mule to enemy bullets and shells as contrasted with the bullet-proof car A horse or mule takes three years to grow, while the cars may be turned out at the rate of 6000 a day. If a horse or mule loses a leg, it is out of service for good, but a wheel or other damaged part of an automobile may be replaced within half an hour. Also, an animal must rest, while from the motor-car 24-hour service is obtainable. The new adjunct to the army’s mobility is not only a sort of flivver cavalry; it might be called also ‘“‘flivver field artil- lery,”’ for its purpose is to replace the individually mounted men of motorized units, such as our tractor-drawn ord- nance, and to carry out that general reconnaissance work that all guns require for selection of position and observation points. It is a unit of the motor trans- port, too—a unique cross-country branch of it. For that service it has a carrying capacity of 500 pounds. A final report will be made as soon as a test car has traveled 10,000 miles. Fitting the Last Girder for Greatest Suspension Bridge HE unusual photographs below show how the last and _ largest girder was hoisted into its place in the central span of the world’s greatest suspension bridge, which is nearing com- pletion across the Delaware River between Philadelphia, Pa., and Cam- den, N. J. The great piece of steel was swung up from the deck of a lighter below and quickly fastened in place in the center of the span. The Philadelphia-Camden bridge has the longest clear center span ever suspended. The total length between piers is 1750 feet—118 feet longer than that of the new Bear Mountain-Hud- son River bridge, and 150 feet longer than that of the Williamsburg Bridge across the East Riverin New York City. From end to end the Delaware River bridge is 9600 feet long, and from anchorage to anchorage, 3536 feet. Its huge suspension cables are made {of thousands of tallow-dipped steel wires. Construction work has been under the direction of Ralph Modjeski, famous bridge engineer. Closing, Up the Great Span The picture at the left shows the last girder of the Philadelphia-Cam- den bridge being lifted from the lighter below. At right: Workmen standing ready to guide the girder into place and thus complete the great span of 1750 feet, which is the longest suspended span in the entire world

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POPULAR SCIENCE MONTHLY October, 1925 Would You Poke Your Fingers A Hospital Case from the Monkey House Monkeys make satisfactory patients; some even seeming to enjoy the attention they get when in the hospital. OW would you like to stick your fingers in a lion’s mouth when the proud king of the jungle is con- vulsed with pain and rage from an ab- scessed tooth? And how would you like to force food down the throat of a surly boa constrictor whose appetite isn’t what it ought to be? Doctor W. Reid Blair, organizer and director of the Medical Department of the New York Zoological Garden, doesn’t think anything of it. He’s performed more than 1500 operations on _ wild animals during the last quarter of a century. He says he takes every neces- sary precaution and, pointing to a bottle of chloroform, that he takes no chances. ver, Doctor Blair will tell you of the time he removed a wire that had be- come lodged in the hide of a buffalo, and how the crazed beast, freed of its ropes and lariats, gave a wild snort and made for him: He took that fence.in nothing flat, the ungrateful buffalo thundering and bellowing a step behind. Then there was the time when Doctor Blair operated on the infected foot of a prejevalski, which, if you don’t happen to know, is a wild horse from Central Asia. Just as the delicate part of the operation was concluded, the animal gave one perfectly healthy kick and Doctor Blair flew through space, landing (happily for him) on a bale of hay. It would be a ticklish job if anything ever happened to Khartoom, the Zoo’s prize African elephant. This valuable beast is so vicious now that he never can be approached, and if he happened to get sick or break his leg or otherwise hurt himself, he would have to be shot. Khartoom would kill any man he could reach. He is 23 years old and stands well over 11 feet in height. And he will prob- ably live to be 60. He has two cages, Doctor Blair is shown above dressing a broken leg of an ape with a great connecting door, so that he can be kept clean and free without being approached. Popular fancy considers an elephant as husky and tough as his hide, impervious to bullets and quite immune to ordinary ills. Yet, curiously, the skin of an ele- phant isn’t tough at all. It may resist rifle fire, but it succumbs to bacteria. Elephants have to be carefully watched, for they suffer frequently from eczema. Elephants are subject to brain lapses, too, despite the fact that they are clever, patient, and willing. And that makes trouble for the doctors. Imagine a great big elephant tripping on a sloping run- way, falling just two feet, and fracturing his thighbone. That preposterous acci- dent happened at the Bronx Zoo a few years ago, and even Doctor in a Lion’s Mouthp The V'wid Story of a Doctor Who Does and Lives to Tell of His 1500 Operations on Wild Beasts By Robert E. Martin into a hospital cage to be chloroformed, Karly in his work, Doctor Blair found that wild animals will respond to anesthetics more quickly when they are indoors., The difficult operation on the bear’s jaw was successfully performed. An African two-horned rhinoceros with a badly swollen cheek was found by Doctor Blair to be suffering from necrosis of the lower jawbone, caused by a de cayed tooth. The animal was put to sleep (though the task was dangerous and one of his nostrils had to be stuffed to do it) and the bone was scraped. LION whose mouth kept him in agony was treated by Doctor Blair without an anesthetic. This beast had caught a bone in a molar tooth and was in a frenzy trying to dislodge the impedi- ment with his clumsy paws. Doctor Blair got the lion to the front of his cage and managed to insert a pair of tongs in Blair couldn’t save the beast, worth $4000. He had to be killed. 1 Bears also need plenty of surgical attention. They are fighting constantly with each other and tumbling around on rocks and in pits. Recently a huge Alaska brown bear, in a vicious fight, drove one of his canine teeth (two inches long) through his upper lip. The animal was wild with pain and anger, and Doctor Blair and his assistants had to catch him, chloroform him, pull his lip down by strenuous traction, and then treat the wound. NE of Doctor Blair’s most extraordinary operations was on a bear. A grizzly gota lumpy jaw, a growth something like that common to range cattle. The bear was in severe anguish and had to be coaxed fortune to fracture one of his hind feet. fracture was part of Doctor Blair’s usual routine, but designing the pair of surgical boots was a noteworthy accomplishment and speeded the animal’s recovery Elephant Wears Baceical Boots A little Congo elephant at the Bronx Zoo had the mis- Treating the

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ers tory ¥ ho VES Its 10ns asts artin oroformed, found that anesthetics loors., The ’s jaw was oceros with found by om necrosis 1 by a de vas put to igerous and tuffed to do pt him in octor Blair - beast had 1 and was in the impedi- vs. Doctor t of his cage of tongs in pots ad the mis- reating the routine, but noteworthy ’s recovery October, 1925 his open mouth. The lion fought POPULAR SCIENCE MONTHLY and pattled, beside himself—until Doctor Blair managed to get the tongs on the bone. The beast sud- denly seemed to sense that here was a Samaritan, a benefactor who would allay his distress, and he kept quiet for a moment. Doctor Blair yanked. The bone came out. And the lion lay down and yawned, as though nothing out of the ordi- nary had happened. “~~ WOULD make a charming I commentary on our work,” Doctor Blair told me, “‘if we no- ticed appreciation on the part of our charges for what we do for them. As a matter of fact, we don’t see any response. Most of the animals protest loudly and vehemently. The monkeys act up something awiul. The lions are very ob- streperous.”’ It is true that an animal once treated submits to medical and surgical attention more easily after- ward. There was an orang-outang who was a champion hospital addict. He was constantly looking for attention and was very agreeable about it. The most unusual operation ever per- formed by Doctor Blair was on a great elk, an Altai wapiti or Asiatic elk, which had been in a terrific fight with another of his tribe. This animal had been gored so frightfully that 16 inches of intestines pro- truded from its side. By any ordinary standard, the animal should have been killed instantly, but Doctor Blair caught him, had him crated, washed the intes- tines, put them back in place, stitched the side with 14 interrupted stitches, and bandaged the wound. Daily dressings soon brought the wounded warrior back to health. ON of the most difficult operations performed by Doctor Blair was on a regal lioness, captured by the famous Buffalo Jones in Africa. When the ani- mal arrived at the Zoo, it was noticed she was surly and resentful. She would not Forcible Feeding as Practised at the Zoo When a snake is ill, it will not eat, and the keepers feed it, stuffing the food down to the snake’s stomach, which in this instance was 514 feet from its mouth eat except at night, under cover of dark- ness. She sulked and would not permit an inspection. Finally, after close observation, tiny drops of blood were noticed on the floor of her cage and it was deduced that her claws must have grown into the pads of her feet. Her nails had to be destroyed. But getting this proud lioness to an operating table was a real task, a problem for true ingenuity. Now, the lion-house at the Bronx Zoo is very well equipped, and one of its modern improvements is an elevator, a fixed cage about 5 feet 6 inches long and 20 inches wide. Meat was placed in this elevator and the lioness was enticed into it after considerable difficulty. Once the lioness was trapped, a tarpaulin was placed over the cage, making it airtight, and she was chloroformed from an atomizer pump and roped and tied. Her nails were removed. The lioness then was placed in a sun- Jumbo Goes to the Dentist Unless an elephant runs amuck, he is a great favorite in the zoological gardens, both with keepers and visitors. ‘‘Open, please,” says the doctor, as he treats a bad molar lighted cage for convalescents, 18 by 14 feet, which opens on an outdoor well. She came to slowly. And what a racket she made! She roared and howled! The © whole park resounded with her rage and anger! Sightseers ran up, but one look was enough. The lioness made for the bars of her well, and, though she hadn’t a chance to get loose, that crowd made for the exits. 6 Sen lioness was well again in 10 days and lived to be 15 years old, a ripe age for a lioness in captivity. She died a year ago. And it’s probably true that in the jungle she would have died sooner. It is true that as a rule animals in captivity don’t live as long as those that are free. But, on the other hand, some live longer, for the zoo provides the finest attention, gives balanced food on a strict diet, and affords protection against powerful enemies. There’s a Sambur deer, an Indian deer about the size of a European red deer, that is 23 this October and is stone blind. This sweet old lady, who has the un- romantic name of Fatty, has presented the Zoo with 16 babies, and her keeper refuses to have her killed. Ordinarily, the Zoo wouldn’t keep an animal not healthy, but rules are forgotten in Fatty’s case. She feels her way around and her keeper guards her. A placard on her spacious cage tells the public a little about this old favorite. N EXTRAORDINARY operation on animals, though it is not uncommon on humans, was performed by Doctor Blair on the eyes of an Indian rhinoceros. This animal, a splendid physical specimen, came, to the Zoo with two cataracts over each eye. Doctor Blair performed the needling operation, in which a knife is inserted in the eye and the capsule of the lens is ruptured in order to dilute the opacity. The operation is absolutely painless and is performed on human beings without an anesthetic, but the rhinoceros was given cocaine. The operation was the easiest part. Preparing the patient for the operation (Continued on page 169)

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New Mile Fascinating Achtevements Mark the Progress of Science— Einstein Challenged— A Second Niagara Found POPULAR SCIENCE MONTHLY October, 1925 posts of Discovery VERYWHERE, every day, men with ideas are studying, experi- menting, inventing, exploring the unknown, and giving the results of their efforts to the world. The sum total of their labors marks the advance of sci- ence. It is to help you keep pace with this steady, ever-changing progress that POPULAR SCIENCE MONTHLY presents here some of the month’s most important discoveries and inventions. ~ Will Einstein Theory Fall? ‘THE Einstein theory of relativity soon may fall, and we may have to look for another explanation regarding the mysterious movements of the universe. Professor Einstein himself has just ad- mitted it. If results obtained recently by Prof. Dayton C. Miller at Mount Wilson Observatory are confirmed, he says, it means that the relativity theory does not hold. y For Professor Miller’s results indicate the earth’s motion through the ether. According to the relativity theory, it should never be possible for any one on earth to detect this motion. If all things in the whole universe—planets, stars, and ether—are moving at the same rate and in the same direction, the results of experi- ments on earth would be exactly the same as if all were standing still. But if the earth and other bodies were moving through stationary ether, or at Makes Huge Vacuum Tubes Possible For inventing the first practical airtight seal between glass and copper and so making possible the construction of huge vacuum tubes used in high power radio broad- casting—William G. Houskeeper, of the Bell Telephone Laboratories, recently was awarded the John Scott medal and a $1000 prize by the city of Philadelphia. Mr. Houskeeper is seen holding a great 100,000-watt tube different rates, then there should be a drifting of the ether in their paths that could be observed from earth. Professor Miller first made his experiments from an under- ground chamber, just as Pro- fessor Michelson and Professor Gale of the University of Chi- cago have been doing in tests of. the Einstein theory. Like them, he could detect no motion — evidence substanti- ating the Einstein theory. Their results, however, pos- sibly might be explained by “ether drag.” That is, in some way heavy bodies, such ‘ as the earth, drag along a certain amount of ether in their motion, leaving the more distant ether unaffected. To test this, Professor Miller repeated his experiment at Mount Wilson, which is about a mile high. And here he obtained the surprising results that may contradict the rela- tivity theory. He found a marked effect that seemed to vary with altitude. _ Snapshots in Colors SIMPLIFIED method of color photography recently demonstrated in Paris, may hasten the day when we all can take snapshots that will register green trees and blue sky. Instead of the old color photograph method, requiring three separate exposures, Rous- seau (discoverer of the new method) found that he could get better results by a single exposure of three films placed one upon the other in the camera. Only asingle plateneeds to be developed. The first film registers blue and violet, the second green, while yel- low, orange, and red are registered on the third. Submarine Telephone Luscious New Berry NE of these days you will go to the grocery store and discover a new dewberry—one that is larger and marines possible. This undersea telephone transmitter is part of a remarkable new instru- ment that makes under-water telephone communication between sub- It is the invention of Dr. Harry C. Hayes, U.S. Navy marine signaling devices. more luscious than any you ever have seen. It will be wine colored, some what darker and sweeter than the logan. berry. It is more resistant to disease than the ordinary dewberry, and it is believed that the new fruit even May replace the popular loganberry on the Pacific Coast. A Louisiana electrical engineer, B, Young, who breeds plants as a hobby, obtained the new fruit by crossing two varieties of dewberries. The Unite States Department of Agriculture cop. siders the size and quality of the fruit so important that it is propagating stock so that the new variety may be released to the public through nurseries. Another Niagara Found A WATERFALL as great as’ Niagara in the midst of a barren desert was one of the sights seen by Mrs. Agne Chase, botanist of the United States Herbarium, who has just returned to the United States after seven months in the wilds of Brazil. Looking for peculiar species of grass, she went high into the eastern plateau where the land hag become a desert through overgrazing, She climbed the highest peaks in Brazil east of the Andes. The man who revealed to the modem world the ancient Maya civilization that flourished before the time of Christ in Central America, has come home. Edward H. Thompson has spent 20 years res- urrecting Maya ruins. His _ greatest single feat in a list that sounds like captions to a movie thriller, was diving to the bottom of the Sacred Well at Chichen Itza, Yucatan. physicist, inventor of the sonic depth finder and other important sub- He is shown demonstrating the apparatus

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Ictober, 1925 ry | ever have red, some 1 the logan. to disease , and it jg even May ITy On the neer, B, M. Sa hobby, rossing two he United ulture con. of the fruit rating stock be released S. Found as’ Niagara desert wag Mrs. Agnes ited States irned to the mths in the or peculiar gh into the land hag »vergrazing, <s in Brazil the modern ization that f Christ in ne. Edward years res- is greatest sounds like was diving the Sacred a, Yucatan.

w instru- feen sub- ,S. Navy tant sub- pparatus

October, 1925 There, 80 feet under water, he found the bodies of 90 sacrificed maidens, together with priceless quantities of jade, gold, and incense. The water in the well was only 40 feet deep, but below it was 40 feet of mud. Mr. Thompson went to Boston and got a job scraping the bottom of deep-sea vessels in a diving suit; then, with knowledge of this work, he re- turned to Yucatan. By throwing logs down into the well, he figured out the spot where the treasure and maidens must have fallen, then had the mud dredged from that part. After that came the dangerous diving, which resulted in the ultimate recovery of the treasure.

Radio Fights Forest Fires | agape are being made this year to use radio over the whole Western forest area to aid in fighting and preventing forest fires. By means of instruments that register humidity very exactly, it is possible to forecast with accuracy the sections where fires are likely to occur. With warnings broadcast, firefighters can be on the spot ready to prevent fires or control them when they break out. Tall trees are used as poles for radio antenne. Are We All Abnormal? VERY one of us is abnormal at some time or other, according to a recent statement of Dr. George W. Henry, a New York psychiatrist. What we call a normal person is one who possesses the average characteristics of a great variety of individuals, he points out, but along with these common char- acteristics there are often many queer ones. To bear this out, Doctor Henry calls attention to peculiarities of famous men commonly regarded as normal. Beethoven, the composer, would use several pitchers of ice-water to wash his face and hands, splashing it about so that it leaked through to the ceilings below.

POPULAR SCIENCE MONTHLY

Forty Years of Progress in Transformers Compare the modern transformer (above) with the first transformer built by William Stanley in 1885, indicated by arrow and shown in lower picture. The modern unit weighs 1000 times as much and gives 10,000 times more power Chopin was so extremely nervous that he was tormented by such trifling things as a wrinkle in a rose leaf. De Quincey, the writer, had halluci- nations and set fire to his books and papers, while Balzac believed that his

37 writings would reform the world, One evening, having put on a new dressing-gown, the latter warited to go into the street with a lighted lamp to excite the admiration of the public.

Defense Guns Prove Deadly ARGETS only five feet wide and 19 feet long, towed behind air- planes traveling 70 miles an hour at a height of 6000 feet, were comparatively easy marks for the United States Coast Artillery anti-aircraft guns in a recent test. The recorded percentage of the hits scored was 5.6, which meant one hit for each 18 shots fired. That is about six times as many hits as were claimed for the firing at the end of the World War, say government officials.

Circles Britain in Five Hours FLYING at an average speed of 151 miles an hour, Captain F. L. Barnard recently won the “around Britain” race for the King’s Cup in England. It took him five hours, 17 minutes flying time to make the circuit of 804 miles up the east coast of Britain, across Scotland, down the. west coast and across the island to the starting point. He used a 395-horsepower plane. This was Captain Barnard’s second victory. Makes Old Hens Lay N OLD hen for chicken pie. It may be diffi- cult to get one for this pur- pose if an experiment made by Dr. F. A. E. Crew of Edinburgh University be- comes well known. By administering thyroid to

chickens he claims he can make hens lay as long as they can cackle. Some hens that had laid only 25 eggs in the previous four years laid more than 100 eggs during the year that they were given thyroid, he found.

Reconstructing the 30-Foot Tail of an 80-Foot Dinosaur Professor Charles Gilmore, curator of the National Museum, Washington, D. C., is seen here at work reconstructing the tail of a huge dinosaur dis- covered by him at the Dinosaur National Monument in Utah in 1923.

The tail is 30 feet long and is composed of 32 vertebrae. The length of the complete animal was 80 feet. Professor Gilmore expects to complete the work of restoration of this prehistoric reptile: sometime in 1927

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Above: car wheels. Right: freight car, or crushed between cars in doing his work, a railroad switch- man’s job is one of the most dangerous, and casualties have been appalling. For this reason a new mechanism installed in Gibson, Ind., which switches and con- trols the cars automatically, is attracting wide attention. Replacing an army of switch tenders and car riders, a few towers have been erected in the railroad yards. In these elevated cabins, operators work electro- pneumatic switches, while below freight cars slide toward any one of 30 destinations. Hump switching, the most approved method of assembling cars for given destinations, is retained in the new P 'rrciete from the icy top of a POPULAR SCIENCE MONTHLY October, 1925 Safety at the Switches Dangerous Freight-Yard Jobs Noy The Old and New Ways of Switching Cars Remarkable new automatic braking and switching mechanism installed at Gibson, Ind., showing control tower. rails are pairs of movable bars, driven by compressed air, that grip the The old and dangerous method of hand braking At the sides of the system. ‘Trains to be classified are pushed up to the crest of a hump, where each car, or group of cars coupled together, is un- coupled and allowed to run by gravity down a short, steep grade. By the old method, as the cars raced down the incline, each had to be mounted by a rider who regulated the speed with hand brakes. The new switching device, invented by George Hannauer, vice president of the Indiana Harbor Belt Railroad, is called a “‘car retarder.” It consists of movable bars from eight to 10 feet long, assembled in units of from 32 to 40 feet, in pairs on either side of each rail. | By means of a compressed-air cylinder and a system Performed by Machine; Automatic Emergency Stop An electro-pneumatic ap. paratus that ‘‘throws skates” mechanically to stop a wild- running freight car now is contained in a box beside the track, ready for emergency of levers, these pairs of bars can be closed like a vise on both sides of al] wheels passing between them. The retarder is so powerful that a car can be stopped and held on the steepest part of the incline whenever necessary. Two hundred and forty feet of retarders arranged in seven units with space be tween, give the first operator control of movements down the incline. Forty-four other units distributed about the yards are operated by four other men. An ingenious auxiliary of the retarder is a ‘‘skate throwing machine’”’ to halt any car running wild. By the movement ofa § lever in a control cabin, an electro-pneu- matic device places a heavy cast-iron wedge on the track to bring the unruly car to a stop. The former method of “throwing skates” by hand was extremely dangerous, resulting in many deaths, Ingeniously Simple Water Turbine Develops Cheap Power represented by the flow of water in rivers and other water channels always has been a prob- | » represents utilization of the energy Suess, an engineer of Vienna, invented a water turbine of a new type, simple of construction, inexpensive, and developing a high degree of power for plant use, The Suess turbine consists of a slighty conical housing, with a built-in four bladed propeller. ne lem. Where the angle of descent, the drop, is great, or where natural falls interrupt the flow, the solution of the prob- lem by dams and arti- ficial falls or by the construction of sluices regulating the volume and direction of the fall- ing water, is compara- tively simple. But in nearly all cases the en- gineering work involves the expenditure of money, often entirely out of proportion to the results obtained. turbine is submerged the stream and is s curely anchored in pose tion, with the smalla@ opening of the housing pointing against the cur rent. The water, enter ing through the smalle opening and passing out through the larger, Te lieves the propeller of stemming counter pre sure and greatly it creases its power. The Suess turbine, being sub- f merged entirely and rest ing on the bottom d the river, does not in- Recently Eduard Powerful water turbine invented by Eduard Suess, Vienna engineer terfere with navigation.

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rgency Stop eumatic hrows skates” 9 stop a wild- : car now is pox beside the or emergency hese pairs of - closed like a th sides of all sing between ie retarder js | that a car yped and held epest part of sary. ot of retarders ith space be- or control of ». Forty-four ut the yards men. ' the retarder e” to halt any 10vement ofa & electro-pnet- avy cast-iron ig the unruly oar method of was extremely nany deaths. wer plant use, s of a slightly built-in four peller. Th submerged 1 a and is hored in pose the smalle * the housing rainst the cut- water, enter h the smaller id passing out he larger, Te propeller o counter pres greatly it- power. The ine, being sub- ‘irely and rest- e bottom of does not in- h navigation. October, 1925 Human Eye Outdone by New Color-Sorting Machine menting there recently has been perfected a remarkable machine that automatically separates cigars into 3) different groups, depending on the shade of the wrapper. The machine consists of a finger that picks up each individual cigar, a photo- electric “eye” that measures the color, an amplifying panel that boosts the infini- tesimal current generated in the eye, a switching ammeter that actuates the mechanical sorting mechanism, and a set of 30 compartments arranged around a common center into which the cigars are ee five years of patient experi- POPULAR SCIENCE MONTHLY Below the “eye” is an- other chamber containing four small _ electric-light bulbs, shielded from the tube above. When the finger places the cigar in position within this lighted chamber, a shutter opens a slit in the covered tube chamber aboveit, and only the light that is reflected passed skilfully, The cigars are fed into a hopper mounted above and to the side of the photo- electric cell. From the bottom of this hopper .an ingenious split finger picks the cigars one by one with meticulous care and carries each to the bottom of the “eye” tube. The “eye” is a tube with two terminals connected with a battery. One termi- nal is enlarged within the tube and heavily coated with potassium. The en- tire tube is covered by a lightproof case, and in the darkness no current flows between the two terminals. Light, however, activates the potassium- covered end and permits current to flow. from the wrapper to act upon the tube. the cigar, then, determines the amount of current permitted to flow between the the cigar is permitted The actual color of Cigar Color-Sorting Machine in Operation 39 Feeding cigars into the machine to pass under the photo-electric eye, which automatically sorts the cigars and drops them into the correct compartments of circular table. mechanical finger that is about to hold up cigar to the ‘‘eye” At left: Arrow points to two tube terminals. And, since every color reflects a different amount of light, the machine’s color-sorting abilities de- pend on its detection of varying currents. Remarkable Bullet-Proof Gas Tank ace to the pilot of the fighting | NDOUBTEDLY the greatest men- airplane is the danger of fire caused by an enemy bullet’s penetrating the gasoline tank. Even if a bullet hole The Controlling Mechanism When a projectile strikes the gas tank, it causes an expansion of the gasoline. This ex- pansion starts the mechanism, which re- volves the inner tank enough to close the newly made hole. Note the wheel that turns it in the tank does not immediately burst into flames, the gasoline will flow out and the aviator will be forced to land. Mario Garagnani dei Pescara, an aviator during the war, has just patented a gasoline tank that, he claims, will over- come these difficulties. It consists, really, of two tanks, one inside the other. Both inner and outer shells are made of fiber one-eighth inch thick. In addition, there is a one-fourth-inch layer of granulated sheet cork and a one-sixteenth-inch layer of sheet rubber on the outside of the inner shell, and a lining of the same kind on the inside of the outer shell. This ar- rangement brings the two layers of rubber in contact with each other. The operating principle upon which the ’ tank functions consists of rotating the inner shell a few inches each time a bullet penetrates the tank. Castor oil is used as a lubricant, since it has little de- teriorating effect on rubber. On the end of the tank is located the mechanism that automatically rotates the inner shell when a bullet strikes the tank. The expansion of the fluid in the tank, caused by the rapidly moving projectile, in- directly throws electrical switches that engage two clutches and these transmit power from a flexible shaft for Airplanes Greater Safety for War Pilots The inventor adjusting the flexible shaft that transmits power from the airplane motor to the mechanism that operates his bullet-proof gas tank connected with the motor of the airplane to the worm gear that rotates the inner cylinder. The rotation places the hole in the inner tank in contact with the wall of the outer tank and this stops the leakage of the fuel. The tank was tested recently by the United States Army Air Service and it is stated that it withstood not only the terrific shock of the .50-caliber machine- gun bullets, but that the controlling mechanism functioned perfectly and stop- ped the leakage that ordinarily would have drained the tank. A means is pro- vided for automatically disconnecting and dropping the tank from the airplane.

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traps star erp rae ea New Army Gas Mask Has Phone for Field Work (,ROTESQUE is’ the telephone gas mask, developed recently by the U. S. Chemical Warfare Service. It is designed chiefly for use by advance posts during attack, that the wearer can tele- phone information to stations in the rear. The wearer is said to be heard clearly even in the heaviest firing. The telephone connection is inserted near the mouth- piece. When the mask is adjusted, the wearer is unable to speak to any one near by. His only means of communication is by telephone. Scientist Uncertain if Tortoise Is Deaf or Stupid "T ORTOISES are either deaf or stupid. Most water snakes cannot hear at all, but land snakes often have acute hearing. These interesting conclusions were reached by Ryo Kuroda of the College of Niigata, Japan, after extensive experiments with reptiles. To test the tortoise’s hearing, scraps of meat were laid on a broad copper plate. When the tortoise attempted to snap up a bit, a bell was rung and at the same time an electric current was passed through the plate. The idea was that if the tortoise could hear, it would soon associate the ringing of the bell with the shock. But repeated experiments showed that the ringing of the bell meant nothing to the animal. It snapped for the food, any- way, and was just as surprised by the shock each time. British Scientist Says Men Can Live for 150 Years T THE mere cost of 12 cents a head, the span of life may be extended to 150 years, claims Sir Ronald Ross, the British scientist, whose researches have led to cures for malaria and sleeping sickness. His idea is that 12 cents from the pocket of every Englishman spent in scientific research would result in a new medical knowledge that would keep germs and old age away so that man easily could live 150 years. He thinks that the allotted span of threescore years and ten should find man in the prime of life. We live curtailed lives, he says, because we are the prey of countless germs. POPULAR SCIENCE MONTHLY Newest Umbrella Folds into Thin Ten-Inch Roll HEN the shower is over, you roll up the umbrella and put it in your pocket. The roll is only 10 inches long and 21% inches in diameter. Frank J. Pugel, of Pueblo, Colo., the inventor of this ingenious device, is a true friend of the man who hates to carry an umbrella. The ribs of the umbrella are hinged in the middle so that the outer half of the top folds back, while the inner half folds in like the ordinary umbrella. The handle telescopes. Opening and closing the umbrella is done by screwing or unscrewing the handle a few turns. How umbrella looks opened and closed A BILL has been proposed in the Cal- ifornia Legislature requiring all ‘per- sons who make camp fires to carry a license. This is intended to stop forest fires, which have caused such heavy losses of valuable timber every year. October, 1925 Neck-Shaped Air Pillow Assure Travel Comfort GHAPED to fit around the neck, a ney air pillow, used as a head rest, jg suited especially to the needs of travelers, In spite of the pitching of the boat o shipboard or the shaking of a train, g person can enjoy sleep with a cool pillow such as this that stays in place. It canbe used, also, in automobiles or for invalids, The pillow, when folded, may be carried in a coat pocket or handbag. The tapeg are supposed to be drawn across the chest and fastened about the waist. Cannot Tell Sex of Chicken by Shape of Egg SOME declare that long, slim, heavy eggs produce roosters, while the small and shorter ones become pullets. The U. S. Department of Agriculture says that you can tell nothing about the sex of a chicken from the shape, size, or weight of the egg. You can tell it only after seven or eight days of incubation of the egg. Experiments have determined that the greater the number of eggs a hen lays before being put into the breeding-pen, the larger will be the proportion of females produced by her eggs. Government Tests Beef by a Chewing Machine 6 weg tough beefsteak—would it af- ford you any satisfaction to know exactly how tough it is? Anyway, the United States Bureau of Standards is in- terested in knowing just what is expected of a man’s teeth when he is served broiled, baked, or boiled Texas steer. The photograph at the right shows a machine devised by the bureau to twist or mechani- cally chew beef while an automatic counter on the ma- chine records its efforts. The Bureau of Standards has not advertised this ma- chine as a house- hold device, yet there may be a de- mand for similar machines from the long-suffering housewives, who could use it to prove to the butcher that the steak is too tough for family consumption and must be returned, or to their husbands that it is tender, as occasion demands. ' U. S. Government expert testing toughness of meat by a machine that is said to pull and ‘‘chew’”’ in order to decide what shall be the standard of “prime’’ meat

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October, 1925 Ww Assures t neck, a new ead rest, ig of travelers, the boat on f a train, g a cool pillow -e. It canbe for invalids, ay be carried . The tapes oss the chest thicken 8 slim, heavy ile the small ullets. The culture says ut the sex of ze, OF weight it only after pation of the ned that the , a hen lays yreeding-pen, on of females lachine ; to prove to too tough for , be returned, it is tender, nent expert ess of meat iat is said to w’’ in order shall be the rime’’ meat Novel Gravity Scales for Weighing Light Mail E bard new scales for weighing letters and other pieces of mailable matter is operated entirely by gravity. There are no springs to become weak with age and give incorrect weights. In operation, the letter is placed on the pan and the cylinder weight is moved along the rod until a balance is struck. Then the weight is read from the measure below the cylinder at the point where the line is cut in the cylinder. Cardboard Is Used for Kitchen Utensils oe ty invented and pat- ented in England is a process by which cardboard pressed into the shape of various kitchen utensils can be so treated as to render it water- proof and acid-resisting. The cardboard kettles and saucepans are dipped into a solution of asphalt, resin, shellac, and spirit and allowed to dry in the air. It readily can be seen that the process offers wider possibilities than mere kitchen utensils. POPULAR SCIENCE MONTHLY Hanging Weight Holds Papers Securely on Spike File HEN the electric fan is running or a gust of wind comes tearing through the open windows of a busy office, papers are likely to blow off the spike type of letter file. J. M. Milling, a telegraph operator at Dallas, Tex., got tired of chasing tele- grams that blew off his desk whenever he had the windows open or the electric fan turned on, so he invented the new letter file illustrated. A weight suspended on a chain, hanging from a crosspiece above the spike, pre- vents the papers from blowing away and yet it does not obstruct the sharp point of the file when papers are to be slipped on. The loose-hanging weight prevents pa- pers from being blown off this spoke- shaped file CANADIAN sugar, which comes from the leaves of the Douglas fir-tree, is now being studied intensively by Prof. John David- son, botanist of the University of British Columbia. This sugar is an exudation from the needles of the fir, and sometimes hangs from the tips of the leaves. It is exceedingly sweet. Stout Co-Eds Grow Slim by Machinery Aperson desiring to get thin, lies with nose compressed and mouth covered with rubber that leads into an air tube. Her breath- ing registers on a dial the smallest amount of food on which she can live. If she adheres to this amount, she will lose weight MACHINE that tells them how to reduce has captured the interest of women students at Co- lumbia University in New York City. The student lies down, a rubber mouth- piece is clamped over her lips, and a pair of pincers fastened on her nose. The mouthpiece leads to a tube through which air is driven by an electric motor. A dial records the air pressure for 10 minutes. From the reading, telling the amount of oxygen con- sumed, the number of ecal- ories or food -heat units needed by the student, can be figured. The small dial can tell the smallest quantity of food on which the girl can sustain life. The rest of the re- ducing process is merely keeping her daily rations near that limit, which, she | may protest, is the hardest task of all. ge Adjustable Apparatus Gives a Straight-Line Bob PERHAPS not quite as good, but al- most as good as when the barber does it. A device has been invented to help the mother make her children’s home hair bobbing look more professional. A metal gage fits on the head like a cap. It may be adjusted with a screw in the middle to the length of hair wanted. Follow the lower edge of the bottom band with the scissors, and a perfect bob, it is claimed, will result. The apparatus is also a time-saver, for this method of cut- ting takes only a few minutes. Marvelous ‘‘Brass Brain’’ Has 15,000 Separate Parts HE “brass brain,” a device that can predict what the tides will be in any seaport in the world at any time—for to- morrow or 100 years from tomorrow—is in constant use in the laboratory of the Coast and Geodetic Survey, in Washing- ton, D. C. The machine is said to do the work of 60 mathematicians, and actual check on the predictions proves it to be nearly 100 per cent accurate. At present the “‘brass brain” is being used to predict the tides at 85 ports all over the world. As a result of these predictions, the department is able to tell two years in advance what the high-water mark will be at 3500 other ports. The idea was conceived by R.A. Harris, Chief Mathematician of the de- partment, and the plans and construction were under the direction of E. G. Fischer, M.E. It took 15 years to perfect, and its name is derived from the fact that practically all of its 15,000 parts have been made Of brass. Even the extra day in Leap Year is given consideration by the wonderful “‘brass brain.” New Bank-Teller’s Cage Is Robber-Proof L* * Soees is claimed to be a bullet-proof, gas-proof, and robber-proof bank- teller’s cage, was invented recently by H. P. Grohn, a mechanical engineer of Chicago. The cage is made of sheet steel. A series of mirrors, a speaking-tube, and a patented lock drawer are designed to pro- tect completely the bank employee and yet enable him, while dealing with legiti- mate customers, to maintain a sharp lookout on all sides for robbers.

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ale Sete hese Soo aNd ne ucer

A Modern “Tree Dwelling”’ The primitive tree- dweller’s idea of a home has been com- bined ingeniously with elaborate twentieth- century architecture in this remarkable “‘house on stilts’? that is near- ing completion for Cleveland Walcott on Riverside Drive, New York City. Instead of resting in the trees, however, the residence is supported by tall steel girders. It is high on a cliff overlooking the Hudson River, and when finished will pro- vide an unusual amount of light and fresh air No Place like Them LS »

; | Home in a Water Tower A water tower that stores 30,000 gallons to supply the town of Thorpeness, Eng- land, recently was camouflaged into this unique five-story house, where lives the family of Mrs. Malcolm Mason, a well known writer of children’s stories and poems

Comfort in the Desert By tunneling into a mountain and constructing most of his house under the earth, a Barstow, Calif., resident finds protection from intense heat

Its Roof Is a Parasol For protection from the hot sun, this emergency hospital building at Needles, Calif., carries a parasol in the form of a second roof set a few feet above the reg- ular roof. The intervening air space serves as insulation, keeping the house cool A Seaside Boat Cottage At Aldeburgh, England, a ship recently was called into service to help solve the housing problem, as shown at the left. A second story was built above the hull, with shingled exterior and a tin chimney

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Ctober, 1995 er gallons s, Eng- ito this ves the a well d poems un, this Yeedles, rm of a the reg- e serves se cool ge ecently lve the he left. he hull, himney October, 1925 POPULAR SCIENCE MONTHLY 43 Where Science Goes Down to the Sea New Wonders of Marine Engineering and Invention A Service Station for Ships No longer need Uncle Sam’s warships hurry to shore to replenish their fuel supply. To- day there are filling stations along the ocean highways, just as there are service stations along country roads. These ocean stations are tankers to which oil-burning vessels tie up for fuel. The photo- graph at the right shows a U.S. destroyer at sea taking oil froma tanker through a long hose stretched between the two tied vessels Model Electric Yacht Equipped with Radio Electric lights and even radio are part of the elaborate equipment of an electrically driven model yacht built by C. B. Hollis, of Brooklyn, N. Y., shown below. The craft, 40 inches long, is driven by concealed dry batteries Radio for Lifeboats Under a new British law all passenger ships must carry at least one radio- equipped lifeboat. The above pic- ture shows one of these boats with antenna masts on the S. S. Orbita. It can send messages 100 miles Lifting the Majestic A world’s record in weight lifting was made recently when the huge 60,000-ton floating drydock at South- ampton, England, lifted the great Atlantic liner Majestic, weighing 56,551 tons, high and dry, as shown

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44 Device Limbers Pianist’s Hand © MAEING fingers supple by machinery is a new and royal road for pianists, said to do away with hours of tedious finger exercises. of the fingers. The natural tendency is for all fingers to work to- To counteract this, an apparatus has been devised that makes every finger move separately. Five minutes of machine exercise, the inventor claims, is equal to half an hour of technique practice. Light pressure of thumb-screws holds the fingers in An eccentric cam makes the fingers move in various ways entirely contrary to instinct; another machine trains in octave spreads. gether. place in sockets. How fingers are held on limbering machine Diesel Engine Supplants Mule in Newest Canal Boats WO low, oddly shaped boats have been put in operation between New York and Duluth by way of the New York Barge Canal and the Great Lakes. Instead of the familiar snub-nosed prows of the old canal boats, the new ones are pointed at the front like torpedo boats. The hulls are constructed entirely of steel and the pilot house is placed exactly amidship. From a distance the canal boats look exactly like giant submarines just coming to the surface. They are nearly three times the length of the old-fashioned canal boat, but retain the same width and low decks. They are driven by Diesel engines, making 10 or 12 miles an hour, nearly five times the speed of the mule-drawn eanal boat. A large section of the hold is equipped with refrigerating apparatus. Movie Star Wears a Watch in Her Shoe-Buckle “HE feet kept time as the music played.’’ There is now a more exact meaning for that phrase since a watch found a place in shoe-buckles. The one illustrated is a tiny Swiss model worn by a famous movie star. A question sug- gested by this un- usual way of using a timepiece is: What happens tothewatch when the lady’s feet are stepped on? \ Watch is set in tibbon of slipper A Frenchman has invented a machine for limbering up the muscles POPULAR SCIENCE MONTHLY “aa Controls Trein | 300 Miles BE tIsSH railroads, as a feature of their one shundredth anniversary, are demonstrating at the British Empire Exhibition at Wembley the most modern methods of control and various new signaling devices. Away Electric lights on a control board indi. cate the progress of trains on 300 miles of | line. The photograph above shows a signaling installation model of train. control methods as used in the British Empire today. ONE hundred new flowers were brought to the United States recently when Dr, Francis W. Pennell, of the Academy of Natural Sciences, Philadelphia, returned from an exploration trip to Chile and Peru. They are all species of the foxglove, snapdragon, and lady-slipper family. Bottle Lock and Key Save that ‘Pre-War Stuff’’ BOTTLE under lock and key is not a new thing. But in this instance, the lock is not on the cupboard, but on the bottle itself. The butler or friend who would help himself to the contents . without the owner’s permission, is foiled. Only the owner possesses a key that fits the lock and that goes on his personal key-ring. Not a drop of the beverage escapes without his knowledge. NEWSPAPER files usually last about 20 years. The New York Public Library now has each newspaper sheet pasted between tissue-paper, which should prolong the life of the file about 100 years. Model Eiffel Tower Is Made of 11,000 Toothpicks pcLevEN thousand toothpicks and 300 hours of time were put in this unique model of the famous Eiffel Tower in Paris. The only tools that Meyer Stein, 19 years old, of New York City, used in making it were a pot of paste and a pair of tweezers. Each toothpick had to be handled singly. The young model-maker is a student at the New York College of Dentistry, which may account for his choosing toothpicks for building material. Each toothpick of this beautiful model had to be put in place separately with tweezere

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ay of their one monstrating at Wembley and various | board indi. 300 miles of ve shows a 1 of train the British — yere brought ly when Dr, Academy of lia, returned 0 Chile and the foxglove, r family. 1 model had ith tweezere A Portable Machine-Shop HEREVER there is an electric- light socket, the handy man can have a power workshop. Sawing, buffing, lathework, grinding, drilling, polishing, and cleaning can be done with this new compact metal and woodworking outfit. A power lathe bolted to a platform is operated by a simple back geared motor. Sticks 12 inches long, and bowls or can- dle-stick bases as large as six inches in diameter can be turned on the lathe. Holes may be drilled in steel up to one- fourth inch in diameter and in wood up to one-half inch. The outfit has a metal cover and may be carried to the job. THIRD-DIMENSION motion pictures, ones that have deptheffects as well as width and height, are produced by a new mov- ing-picture camera exhibited in Chicago. Famous Violinist Brings a Unique Cane from Europe HEN Jascha Heifetz, the famous violinist, returning recently from a trip to Eu- rope, walked down the gangplank of a steamer in New York, he carried a curious cane. It had the shape of a heavy walking stick, but it had strings like a violin and actually could be played. It was a sou- venir from abroad that the artist had “picked up,” as the tourists say, and for which he had paid $400. Mr. Heifetz was delighted with the unique instru- ment, and said its tone was really not at all bad. POPULAR SCIENCE MONTHLY 45 Where the Diver Met Her Shadow OST unusual was the photograph taken recently at the opening of the largest swimming-pool in the world, built at San Francisco. flight. The honor of the first splash was accorded to Miss Mavis Cochrane, a co-ed at the University of California. Miss Cochrane dived, a murmur of admiration arose at the graceful Only a few near-by spectators saw what the photograph shows—a reflection so clear that it had the appearance of another diver beneath the water meeting the real diver above. The new pool is 1000 feet long, 150 feet wide, and requires more than 6,000,000 gallons of water. The cost of the pool and building, which has 750 dressing-rooms, was $100,000. When It could accommo- date easily all swimming contestants in the Olympic Games. Smallest Lighthouse Model Is Made of War Waste MaPE by a sailor, this unique model lighthouse is accurate in every de- tail. Daris Hussman completed it re- cently for the United States Shipping Bureau, after working on it nights for three years. It is made of 36 shells collected from the battlefields of France. The lizht- house is electrically lighted and is equipped with a motion-picture projec- tion machine light that casts a beam that may be seen for quite a distance. Look- ing through the little windows one can see a kitchen and other living-rooms uf the lighthouse, completely furnished. BuTTER that keeps longer is being made in Holland by churning it in the presence of carbon dioxide. The air that is naturally in a churn is drawn out and replaced with carbon dioxide. Part of this works into the butter and remains there a long time, keeping out air, which is the chief cause of deterioration. The increased expense of this method is said to be small. Unusual reflection of a diver IN A new Cunard liner all the clocks are driven electrically and controlled by a master clock. This has a chronometer escapement instead of a pendulum. Bicycle-Scooter Is Newest Plaything for Children "THE little fellow who wants a bicycle like dad’s will be delighted to know that a new plaything has just been put on the market for him. It is a scooter- bike, a cross between a scooter and a bicycle, as much fun as a bicycle, but easier and safer to ride. It has rubber tires, a spring bicycle seat and handle-bars. The rear wheel is free, while a hand brake is provided for the front wheel. An adjustable seat permits the bike to grow with the child. Another model, keeping up to the minute in style, has balloon tires and a parking stand. Popular new bicycle-scooter is built also with balloon tires and a parking stand

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46 POPULAR SCIENCE MONTHLY Bees Are the Heroes of Interesting Movie ay 1M ox Pe im s f | HE bee is the latest movie star. The story of its life, full of adventure, travel, and savage warfare, is being recorded in a European moving-picture studio. Doing this accurately requires the as- sistance of a large staff of camera experts and scientists. They wear head nets and hand protectors while at work to avoid being stung by the insect actors. Two of the most interesting parts of the unique film show the building of the hive with its marvelous architecture, and a war against hornets. Above: Setting the stage. Below: A director Nest of Largest Bird Is Found in California N THE mountains of October, 1925 Mouselike Deer ‘Come from the Island of Ceylon, in India ‘THE tiniest deer in the world hay none of the grace and beauty of they larger relatives. They have legs like sticks attached to bodies that have 4 strong resemblance to mice. Their name calls attention to this—‘‘mouse deer,” The word for that in Ceylon, where the queer little beasts live, is ‘‘goton.’’ Thoge shown in the picture were brought to Boston recently, from Ceylon. Thre others of the family died during the long journey across the ocean. Huge Dinosaur Is Transported by Small Electric Car VEN the dinosaur has to bow to modern methods. In the quiet halls of the American Museum of Natural History, in New York City, Ventura County, Calif., E. A. Brown, a young hunter, recently discovered a nest of a pair of condors. The condor is the largest bird in North America, and is believed to be the largest flying bird in the world, sometimes having a wing spread of from nine to 11 feet and weighing about 35 pounds. There are only about 50 pairs of these birds in the United States, and stealing their eggs or killing them is punished in California by a heavy penalty. The cave nest, with an en- trance only large enough to admit one condor at a time, was at the top of a solitary 200-foot pinnacle, standing at a little electric truck busily pulls a platform on which towers the skeleton of a monster millions of years old, Using compact electric power to haul the greatest example of prehistoric brute power, science bridges a gap too vast to be estimated. ~s eagaimti: the end of a canyon. Brown climbed the rock, crawling the Museum exhibit of condors and their nest last 100 feet on his stomach. While midway along the ledge on which the cave opened, the two con- dors swooped at him continually. Brown saw and handled the one egg the nest contained. “The nest,’ he says, “was merely an unlined natural depression in the rock floor of tthe cave, in which rested one pale greenish blue egg, about 14% times as large as that of a do- mestic goose. This egg seemed to have a very thick shell and was very heavy.” Dinosaur skeletons moved by electric truck in New York’s Museum of Natural History

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October, 195 | uselike T ‘Come om the sland of ylon, in India world haye uty of they re legs like hat have 4 Their name ise deer,” n, where the on.” Thoge brought to lon. Three ng the long insported Car to bow to » quiet halls of Natural York City, ruck busily 1 on which leton of a of years old, ectric power est example ‘ute power, yap too vast History October, 1925 POPULAR SCIENCE MONTHLY Ce ceca TT N. Y. Central tracks as they appear today bank of the Hudson River, one of the most attractive parks in New York City, has its beauty marred by railroad tracks, coal pockets, and garbage dumps at the water’s edge. An ingenious plan, introduced by Charles L. Craig, Comptroller of the city, would transform three miles of this un- sightly water-front into playgrounds, a driveway, a promenade, and recreational centers, at the same time providing for the railroad, which cannot be pushed off Manhattan Island. Land now under water, according to the plan would be reclaimed, in some cases extending the park 250 feet. A 25-foot promenade, for pedestrians only, with a sea wall, would extend the entire length of the new section. Back of this would be lawns and shade trees, with rest houses provided at convenient intervals, where people might sit and watch the passing steamers, or enjoy the view of the majestic Palisades on the opposite shore. RR vast PARK, along the east Lump of Seaweed Said to Be Millions of Years Old A 500-POUND lump of petrified sea- weed discovered in the Medina sand- stone of Pennsylvania, is believed to be 60 million years old. It was exhibited recently at the Department of Geology of the University of Pennsylvania by Dr. Frederick Ehrenfeld. The structure of the sea plants can be seen very clearly in this unique rock, which is but another piece of evidence that the ocean once covered this part of our country. seaside resort. gardens of a pleasure club, a wonderful hree Miles of Railroad to Be Roofed by a boulevard Architect’s drawing shows transformation of tracks and water-front The elieeed tracks would be roofed over by a wide boulevard for automobiles. This would relieve part of the congestion on Riverside Drive, the street now above the park, and would speed up traffic, since the three-mile stretch would be broken by only one crossing according to the plan. The plan provides for 22 acres for play- lawns and tennis-courts. A fresh-water pool three blocks long would be provided, to be used in the summer as a swimming- pool and in the winter as a skating-rink. Glass Dancing-Floor Is Lighted from Below HEN the moon is not shining, one still may dance under the stars at Biarritz, a popular French There, in the beautiful glass floor illuminated from below gives all the light necessary for dancing. The effect is attractive and the idea could be employed as a novelty in both indoor and outdoor dancing-rooms. A fairylike scene at Biarritz, France, where lights shine through a glass dance floor

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48 POPULAR SCIENCE MONTHLY October, 1925 Sky /raffic and Its Progress $y io pi Battle Planes Fly Wing to Wing One of the most effective maneuvers of the British Royal Air Force. Groups of planes swoop forward with breath-tak ing speed while maintaining an amazingly even formation Powerful British Plane Carries 16 Passengers The most powerful single-engined plane in the world was shown at the Royal Air Force Meet recently in England. It is a DH-54 biplane, with a 650-horsepower engine. It will carry as many as 16 pas- sengers, with baggage, at a speed of more than 110 miles an hour Jumps from a Dirigible Parachute jumping from an airplane is not uncommon, but Lyman H. Ford recently jumped from the U. S. dirigible Shenandoah, when it had reached a height of 1500 feet, landing safely in a park The Smallest Airship At Dayton, Ohio, for the first time a commercial airship was inflated with helium (left). It is 110 feet long, con- tains 50,000 feet of helium, the non- inflammable gas, and carries four persons Octo!

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Royal Air eath-take ‘ormation ane is Ford igible 1ed a 4 park me a with con- non- He Calls It an Automobile This freak machine was built of airplane parts by a soldier at Mitchel Field, L. I. Driving and gear-shifting are done from the wheel. The driver’s head sticks out as from an airplane cockpit when the door is shut POPULAR SCIENCE MONTHLY 49 Some Curiosities from the Motor World A Three- Wheeled Automobile-Boat Philip Matcovich, of Long Island City, N. + has invented an automobile that swims. On land the automobile-boat is said to have a 30-mile speed; 12 miles afloat. When the machine enters water, a rudder and propeller replace the rear wheels A Champion Racer Here is Peter De Paolo’s winning tacer fitted with the remark- able supercharger that forces air into the carburetor at high speed. Tests show that the new supercharger raised the Pressure in the manifold about 11 pounds to the square inch A Dalmatian dog is responsible for the photograph above. Miss Louise Hunter, of Atlanta, Ga., owns the dog, and his somewhat startling decorative scheme suggested the gown and the car, with the above result Racer Breaks Rear Axle A car driven at full speed by Leon Duray in arace at Altoona, Pa., re- cently, suddenly broke its rear axle and collapsed. This remarkable photograph shows the peculiar ap- pearance of car after the accident Quick Wit Saves Driver’s Life Quick thinking saved “Dick” Ryan, racing driver, from a terrible death. While driving on the track at Atlanta, Ga., his car caught fire. Ryan headed straight for the fence encircling the track, crashed through, and plunged into a lake below. He made his escape as the car hit the water, suffering only a few scratches about the face Ne ere arene preareTe Smee ae Tn Sp ee a AOE OTT DO EON srerers “ Ss a Sri etatecensadanesnat eI Ta A eer ae pee Cee

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Newest Trousers Press Is a Camouflaged Chair Back 6 TORING a bulky trousers press has long been a problem to the well dressed man and the neat housewife. This particular problem has at last been solved, however, by an English manu- facturer, who has hidden a press in the back of a bedroom chair. The bottom boards of the press form the actual chair back. Two boards hinged to the chair uprights form the top sections of the press. The trousers are inserted, the top boards folded together, and the bottom lever is closed. A pull on the projecting part of the trousers stretches them, then the top lever of the press is closed.

Self-Feeding Shaving-Brush Carries Its Own Soap RESSING on the bottom of the handle of this unique shaving-brush in- jects sufficient cream into the bris- tles for a_ shave. The container, made of hard rub- ber and resembling an oilcan in shape, holds enough shav- ing-cream. for two months’ use. The bristles are set in rubber and the brush is orna- mented with a nick- el plated cap.

THAT France _ se- cretly is building a large hydroplane with which it is hoped to fly the 4000 miles between Paris and New York without stopping, is a recent report from the French capital. The plane will have a motor of 550 horse- power and carry 1584 gallons of gasoline. Pressure fills brush with shaving soap

POPULAR SCIENCE MONTHLY Makers of Collapsible Golf Tee Claim It Improves Stroke [ seer. hard driving the new type of golf tee illustrated at the right flattens out, then springs up in the same spot. This collapsible feature makes it impossible to injure a stroke, it is claimed, and the club head passes over the tee easier than it would on the gritty surface of an ordinary tee. © The tee is made of airplane cloth cemented between sheets of pyroxilin to give it resiliency and endurance.

No flying grit with new golf tee

INSECTS and grubs cause an annual loss of $800,000,000 to the agricultural inter- ests of the United States, and farmers, fruit-growers, and gardeners pay another $800,000,000 each year trying to get rid of these pests.

Frenchwoman Invents

Humane slaughter gun and its inventor $33,000,000 for Buttons [* MAY surprise the average individual to:learn that there are two dozen or more buttons of various kinds on his suit of clothes. The value of buttons manu- factured annually in the United States is more than $33,000,000, according to the figures of the Department of Commerce.

Painless Slaughter Gup SLAUGHTERING cattle by hitting them on the head with an ax is needlessly cruel in the opinion of Madame Simon founder of the French League for the Protection of Animal To replace this method she invented, jp. cently, a revolver of large caliber that kills without a bullet. A powerful explosive drives a four-inch spiked tube with terrific force into the brain of the beast. There is no trigger, The operator simply presses the barre tight against the head of the animal and the spike is fired into the brain auto matically. It afterward returns into the barrel. The new weapon has been adopted for use by a Paris slaughter-house, ;

Snapping Shrimps Make Their Homes in Sponges PONGES are the beehives of the sea, This curious discovery was reported to the U. S. Bureau of Fisheries by Dr, Charles J. Fish of the scientific staff of the New York Zoological Society’s steamer Arcturus, cruising in tropical waters, The ‘‘bees’” that Doctor Fish found in habiting the canals of the sponges were whole colonies of the snapping shrimp Alpheus. These society-loving shrimps, he discovered, swim about freely, but always return to the particular sponge that is their home.

Typist’s Posture Improved by Novel Outfit [ JNLESS she keeps it always in mind, a typist is apt to become round shouldered from sitting in a slouched position before her type- writer. While chairs made scien- tifically to fit the hollow of the back cause her to sit erect, still, she usually has to bend over to read her notes. A new equipment fastened to the typist’s desk helps her to sit erect at work without discomfort. A rest is provided for the feet, tilting the body back properly, while a notebook holder is supported above the type- writer at a good angle for reading.

Serums to Protect Stock ERUM to inoculate stock against diseases, some of which never have made their appearance in this country, is kept in storage at Wash- ington by the U. S. Department of Agriculture.

Se

Typist’s chair and table assure correct posture <a at ei

ple th fec

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tee aY another to get rid r Guo head with me Simon, f Animals, vented, re. aliber that a four-inch e into the no trigger, the barrel animal and rain auto. ns into the idopted for ce Their 45 of the sea, iS reported ries by Dr, staff of the ’s steamer al waters, | found ine onges were ing shrimp g shrimps, freely, but lar sponge utfit a t posture Combination brush has convenient shape POPULAR SCIENCE MONTHLY Clothes and Hat Brush in One Is Handy for Traveling AT brush and clothes brush are com- bined in one handle in this new traveling accessory. The white brush is .softer than the black one and made especially for brushing hats. If the Pullman porter forgets the final touches before you leave the train, you yourself can get rid of the train dust with this brush that slips easily into your traveling-bag. A TALKING wire that can be used by American business men to dictate letters or instructions across the Atlantic, or by means of which European radio fans can record entire programs broadcast in the United States, is the result of 18 years of laboratory research by Dr. Kurt Stille, a German scientist. The apparatus re- sembles a desk telephone and is equipped with both transmitter and receiver. Watch-Chain Safety Catch Foils Pickpocket UNIQUE watch-chain fastener, in- A vented recently by George Stiegler of Cincinnati, Ohio, slides on the belt. The cross bar of a watch-chain slips under a raised part of the fastener, and lies next to the belt. The same chain used when the watch is worn in the vest, thus can be used when the watch is carried in a trousers’ pocket. The fastener is adaptable for all styles of chains. New “Invisible Light’? Renders Opaque Objects Transparent Y MEANS of “‘invisible light” that he recently perfected, Sir Jagadis Chan- dra Bose, a distinguished scientist of India, in a recent demonstration before a group of scientists, proved that a heavy book can be made: transparent. The light, called “‘super-retina,’’ consists of short electric waves having the same properties as a beam of light. These waves are absorbed selectively by dif- ferent substances. Coal-tar pitch is among the objects that it renders trans- parent, while water, on the other hand, is made opaque. Sir Jagadis claims that plants can perceive these invisible beams, though human beings cannot. He per- fected his instrument after 30 years. Simple catch secures watch-chain Surgeon Signs Operation A ‘NEW practice has started among surgeons of signing operations. Dr. Evan O’Neil Kane, of Kane, Pa., marked a patient’s skin with a small amount of India ink in radio code alphabet. Doctor Kane believes that a code could be ar- ranged among surgeons for use in emer- gency operations, when a patient is unable to tell of previous operations that he has undergone. Device Eliminates Movie-Camera Grinding Movie. camera is operated by pressure of a single button y= Y és ; > . Ae ie F a 5 4 : : PR: (BINDING movie cameras by hand will be a thing of the past when the new motor control, invented by Arthur Todd, motion-picture cameraman, is universally adopted. The new device, which is expected to revolutionize the art of cinematography, already is being used in the studios of Hollywood. Instead of the old hand-organ technic, all the camera- man has to do now is press a button that controls the motor, and the film travels. - The photograph at the left shows the cameraman in the act of starting the machine by the new method of simply pressing a button. WITH a three-hour handicap a homing pigeon recently won a race against an airplane, flying between Paris and Brussels, 170 miles, in four hours. Ss Hang Moth Balls in Clothes by Means of New Spiral Holder Mo °t#t balls in a handy spiral con- tainer shaped like a spring can be hung inside a coat on a clothes-hanger, or hung on the door-jambs or hooks in a closet to make the whole closet moth- proof. This is also a good way of placing the balls in blankets or clothes stored in boxes or trunks, as it simplifies their removal when the articles are needed for use in a hurry. LATEST reports from the U. S. Patent Office, through Patent Commissioner Robertson, show that applications for patents are granted now in about two, or not longer than five, months. Commis- sioner Robertson reports that in 1923 there were 72,475 applications pending. A year later the number was 59,000, and at the end of the fiscal year of 1925 only 43,000. Toothbrush Holder Acts as a Constant Sterilizer HEN tooth- - brushes get iat too dry, they be- \—. wade come harsh and stiff and the bris- 1 é tles irritate the gums. A new tube for the brush keeps it at the ith} right temperature, Thh: preventing this. On the bottom of the tube is a cotton pad saturated with a medicated solution that sterilizes the brush between each using. How Uncle Sam Killed Gophers Sterilizing tube OPHERS bur- for toothbrush rowing in. the army landing-fields of the U. S. Naval Air Station at San Diego, Calif., so under- mined them that they were causing serious accidents to landing planes. An appeal was made to the U. S. Depart- ment of Agriculture, which prescribed that poison be poured in the gopher holes and the mounds leveled with a steam- roller. This practically cleared the land- ing-field of rodents.

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52 POPULAR SCIENCE MONTHLY Compact Outfit for Replating Silver at Home Negative and positive wires are adjusted and the plating pad does the work Oc tober, 1925 "THERE is a compact home outfit for replating silver by which the metal is rubbed on with a pad. The negative terminal is fastened to th, article to be plated. The positive Wire leads to the plating pad, a fabric containg holding a dry composition of acids and finely powdered silver or other Dure metal. After being soaked in water, the is passed slowly over the surface to be plated. When the moist pad touches th article, the circuit is completed and the metal deposited. The wiping action is said to have, burnishing effect so that no Oxidation occurs. . Thus it is possible to electroplaty iron without a copper coating. Playful Porpoises Sacrificed to Needs of Watchmakers BSERVING schools of porpoises sporting about in the water, few ocean travelers are aware that these strange animals have supplied them with an important product. The watches ticking in their pockets probably are lubricated with porpoise oil. Oil for timepieces must answer very exacting requirements, among them, in- sensitiveness to heat and cold. At night watches are exposed to chill air after having been carried close to the body all day. The oil must not thicken or con- geal on account of this change of tem- perature. That extracted from the jaw pans of porpoises is said to be unsurpassed for lubricating watches. With the large increase in watch factories in the United States, porpoise-fishing has become an important industry all along the Atlantic coastline. No Inflation in These New, Unsinkable Bathing-Suits 5 det may be a perfect duffer in the water, not know how to swim a stroke, and yet go with safety beyond the six- foot line. That is, if you have on a non- sinkable bathing-suit, designed for the person who cannot learn to swim, and that keeps him afloat and gives him confidence. These new suits, said to have been Houses Built of Steel, Cork, and Concrete OUSES made of cork on steel frames are the latest type of struc- ture built in England, where great efforts are being made to plan houses that can be built. .. rapidly by unskilled labor. Slabs of compressed cork two inches in thick- ness are placed on a steel framework and this is inclosed in concrete, which is applied with a cement gun. The cork insulates against damp- ness, heat, and cold, serving the same purpose as air spaces in concrete or brick houses. Concrete is sprayed on cork-covered steel-frame houses — tried out successfully at beaches near Washington, D. C., recently, are made in one piece, fastening down the front. They are not inflated, but are made of light, non-sinkable material. WHEN your fountain pen runs dry and you have no ink, usually you can obtain a supply of writ- ing fluid by filling the tube half full with water. As a rule, there are enough ink crystals in the tube to make a fairly good writing fluid. ° Pocket Camera Has 100-Film Roll NE hundred snapshots can be made with this minute , “‘vest-pocket”’ camera with a ai single loading. It is not much larger than a box of Swedish Malaria Inoculations Cure N. Y. Paresis Victims ‘THIRTY patients in a New Yok hospital, once believed hopelessly insane, are back at work, leading norm lives, cured by having been infected with malaria germs. The astounding methol of curing a mental disease by inflictin the patient with another disease is med ing with marked success, according t reports issued recently from the Loy Island College Hospital. The malaria method of treating paresis, always considered an incurable disease, was originated in Austria. Malaria germ are injected into the veins of the insam person. After from seven to 14 day when fever develops, it is broken wit quinine and, following this, salvatsa is administered. Just how the malam works to combat paresis is a mystery. safety matches and takes a special roll of film, much like a motion-picture film, without the side perforations. It will take views either from the horizontal position or from the vertical. The exposure speeds range from one second to 1/3000 second. By a special system of ratchets on the film spool, the film unrolls for only a 2h Oh Ges SR Gee tu... ee a one view at a time when the pictures are being taken. New pocket camera that holds 100-film roll contrasted with a matchbox to give an approximate idea of size

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ctober, 1935 me © outfit fo the metal ened to the sitive wir ic container f acids ang other pur er, the pad face to be touches the ted and th . to have ; O Oxidatio, electroplat: g. ncrete me houses — ns Cure ictims a New York od hopelessly leading normal 1 infected with inding methoi e by inflicting lisease is meet , according t rom the Loy reating paresis, urable disease, Malaria germs s of the insant n to 14 days, is broken will this, salvarsa yw the malati is a mystery. October, 1925 Device Controls Sound Waves to Master Record NSTEAD of having the artist speak, Pa. or play directly into the horn, this new invention uses electricity to con- vey the sound waves to the wax record on which they are recorded for the making of nonograph records. The desired tone can be obtained by the use of this device as the sound is regulated by electrical control. Orlando R. Marsh, of Chicago, is the inventor. He is shown in the picture recording an organ number. A new motor alcohol made from mo- iasses and the juice of the sugar palm is said to make starting easy and eliminate knocking and carbon troubles. Its dis- advantage is the cost of making it, but extensive experiments are being made in Hawaii to overcome this. POPULAR SCIENCE MONTHLY Sound waves enter horn at whatever strength is desired by operator of new control Japan Guarding against Future Earthquakes N REBUILDING their great city of Tokio, destroyed by earthquake, the Jap- anese are taking the utmost care to get nothing but good ma- terials. A testing bureau has been es- tablished, somewhat like our government Bureau of Standards. The new buildings in Japan’s capital will be far different from those of wood and paper that fluttered to the ground in the last great disaster, it A corner of Tokio’s recently organized Bureau of Standards is certain. ° Hats Are Made to Fit with a Self-Adjusting Silk Pad Syeda how many hats have been thrown away on account of bobbed heads has not been estimated, but they number in tens of thousands. Old hats will not fit with the wearer’s hair cut off. To make large head sizes smaller to fit smaller heads, a new hat size-reducer has been put on the market. It is a narrow silk-eovered pad, which is pressed into place with three small prongs, requiring no sewing or adjusting. roll contrasted ite idea of size How the hatband is adjusted to re- duce head size, and the band itself TO REST the diseased lung of a tuber- culosis patient, a British inventor has produced a machine which pumps air into the thoracic cavity by way of a hollow needle inserted between the patient’s ribs. Births Now Exceeding Deaths in the United States ALrHouGH the population of the United States is now at the high- . water mark of 114,311,000 people, the ad- vance over last year was less than the average for the last five years, according to recent estimates of the National Bureau of Economic Research. The once rapid ad- vance, it is believed, has now definitely slowed up. That the regular increase in the popula- tion has not been due to immigration, but to the excess of births over deaths, is shown by figures covering the last 16 years. In that period there were more than 41 million births and about 22 million deaths, or an excess of 19 million births. About 514 million were added by immigration, bringing the total in- crease to about 24 million. Of this number, immigrants formed little more than a fifth. Ten years ago the birth rate was 26.2 for each thousand persons, while today it is 23.3. At the same time the death rate has decreased from 13.4 to 11.7. Alabama to Have World’s Largest Artificial Lake — will be the largest artificial lake in the world, is being built in a remote section of Alabama to assure a constant flow of water for driving three large electric generators. These will feed power into the electrical transmission system of the state. With the exception of those at Niagara Falls, the three 45,000-horsepower water- wheel-driven generators will be the largest in the United States. The artificial lake will have a shore line 700 miles long and will cover 40,000 acres of farm and forest land. Agricultural experts believe that the construction of the huge lake will make a vast section of the country to the south of the lake frostproof and advan- tageous for fruit-growing. Man Sails 202 Miles Down the Mississippi on a Mattress KEOKUKT® ST.LOUIS #2 § pi 8 Sj he iB YOU want to take an inexpensive trip, think over the possibilities in your own home in the way of water craft. You might make a raft of the dining- room table, or, there are the mattresses. Sidney Helms, of Des Moines, Ia., had an idea that he could negotiate the 202 milés of Mississippi River between his home and St. Louis on an ordinary mattress. Friends laughed at him, but he tacked the mattress to a light frame and added an outboard motor. The photograph above shows Mr. Helms’ arrival at St. Louis. pe ee II TT

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54 Five Tools in One For window-box gardening a new set of five gardening tools, used with a single handle, is a decided | convenience. The set may be stored away in very little space and yet every sort of tool likely to be needed in such work is available A Knife-Sharpener A tool for sharpening any shape blade is screwed to table or wall. Twin grinding wheels of fine corun- dum are held together by a pressure spring. When being sharpened, the knife blade rests in a beveled groove POPULAR SCIENCE MONTHLY October, 1935 Modern Utensils for On These Pages the Expert Housewife the Labor of Kvery-Day Tasks and Electric Doughnut Frier Doughnuts can be fried by electricity by putting this electric plate inside your doughnut The heated grease circulates throygh the holes of the plate, which is so wired that an even temperature is maintained. The plates are made in several sizes to fit standard kettles kettle. Duster Glove with Cuff A duster in the shape of a large glove is made to fit either hand and has a long cuff that protects waist or shirt, Grease does not penetrate the glove so that a person with a cut or bruised hand is protected from possible in- ae fection while using the duster Three-in-One Kitchen Tool Orange juice may be pre- pared in a jiffy with this little combination house- hold machine. Besides extracting juice, it will beat eggs and _ sharpen kitchen and table knives New Washing Machine Specially built for apart- ment use, this new wash- ing machine stands on one leg and is held by two rubber-covered hooks to the edge of the sink, laundry tub, or bathtub. It is run by water power. Washing, rinsing, bluing, and drying all are done without removing the clothes from the machine Special Brush for Glasses Often it is difficult to get the inside of a glass clean, especially after fruit drinks. The round brush shown at right will do a thorough job of cleansing any tumbler Automatic Pancake Turner At first sight the pancake turner below looks like any other, but it is equipped with a spring that, when pressed, turns a pancake without any effort whatever

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October, 1925 or SC wife S and Cuff ‘ge glove id has a or shirt, he glove - bruised sible in- duster yne ool be pre- rith this | house- Besides it will sharpen knives October, 1925 Single-Burner Top Oven The useful and economical oven shown above bakes over a single burner on a gas, oil, or electric stove. For kitchenettes or camps, _where space and heat must be considered, it will be found especially useful Mop and Wringer Asimple twisting motion forces water to the sur- face of the mop and a metal squeegee rubs it off. The mop has no wooden roller to get out of order and will wring out any soft material POPULAR SCIENCE MONTHLY the Up-to-Date Home Will Find Valuable Suggestions for Easing Reducing Their Drudgery to a Minimum Sealer Straightens Caps A new fruit-jar sealer fits over the top of a screw cap. Damaged caps can be used, since the sealer straight- ens out the edge and prevents leaks A Double Rolling-Pin In this double rolling-pin, one roller, directly back of the other, smooths out any bumps in piecrust or noodles left by the first roller as it passes over them Small Vacuum Cleaner This little hand electric vacu- um cleaner is a complete ma- chine in itself and with the auxiliary dustbag weighs less than three pounds. It may be attached to a light plug Kettle Lights Gas-Ring A gas-burner that lights when a kettle is put over it and goes out automatically when the kettle is re- moved is a new economy device for the kitchen. When the kettle is off, a small pilot light remains burning Reminder Clock for Cooks When it is time to take the cake out of the oven, an alarm-clock goes off. A little knob in the lower right-hand corner sets the dial for time desired Bottle Cover and Opener The combination milk-bottle cover and opener shown at the left is made of metal. The pcinted projection on the cover removes cap easily Vegetable Cooker and Drainer ; Vegetables are cooked in a wire basket that rests in a new type of cooking-pot. After the water has been drained off, the basket is whirled by turning a handle on the pot cover. This leaves the vegetables dry SSS -————— ame aa PE negara anf AS LE OES

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POPULAR SCIENCE MONTH LY Milwaukee man carves oak replica of da Vinci’s famous picture A Picture Copied in Wood som a slab of solid oak, August Eberhart, of waukee, Wis., recently completed a remarkable rv of da Vinci’s ‘“‘The Last Supper.” 2] Great delicacy and fineness of detail in the work it distinctive. effect although working with a slab of the hard wood 4 inches long and seven inches thick. Mr. Eberhart, shown in the photograph with his Wor learned wood-carving when he was only 14 years old A CARILLON of bells in Bruges, Belgium, is famed through. out the world, so it is no mean commendation whe , carillon for America is likened to it. consist of 53 bells, to be erected in the Park Aven, Baptist Church of New York City, the gift of John p Rockefeller. The carillonneur of Antwerp Cathedpy has been engaged permanently to play them in New York October, 19% Mr. Eberhart achieved an almost cam The latter chime Ingenious New Sun Clock Comes from Australia A NEW kind of sun-dial that tells time within 30 seconds of an ordinary clock, has been invented by an astronomer in Australia. It consists of a ring that can move on pivots placed in a north and south plane. On one side of the ring is a small hole, which, when the sun is shining, casts a small spot of light on a figure 8 on the opposite side. This curve is marked with the date for various times of the year and allows for the amount that the sun is ahead or behind its average position. The ring is turned until the spot of light is on the proper part of the curve and the hands, which are geared to it, then indicate the correct time. Know Your Car HE linings of most automobile brakes wear out long before they should, simply because they are used too much. ‘Traffic emer- gencies arise, of course, where a sudden and strong application of the brakes is absolutely necessary. In ordinary driving, however, the use of the brakes should be avoided whenever possible. Instead of keep- ing your foot on the throttle until the last minute, then jamming the brakes, shut off the power in ad- vance, so that the car will slow down gradually with just a touch of the brake. Brakes will last much longer if five simple rules are followed: 1—Coast to a stop instead of jamming on the brakes. 2—Throw car into second speed at the top of long, steep hills, and let the drag of the engine serve to retard the speed of the car instead of the brakes. 3—Keep mud and grit out of the brake linings. 4—Wash the brake linings with gasoline if oil leaks out on them. 5—When you renew the brake linings, be sure to polish the brake drums with fine emery paper if they become roughened. YO € FAIAUTIES FOR YESTERDAY * a QOl7 i 2M oforz! _ Ae TOTAL TS wes es v pas bo recomlliaaa—aa Warning Traffic Signal Is Built like Speedometer A UNIQUE warning signal made to resemble an automobile speedom- eter warns motorists in St. Louis of the seriousness of careless driving. At the top, where the mileage figures usually go, is the number of deaths from motor acci- dents that occurred the day before. . Beneath that, in the place where mile- age usually is recorded, are the number of total deaths for the past week and total deaths for the year. A sign below gives the total of motor deaths during the same period a year before. Signs radiating from the “‘speedometer”’ give bits of advice. THERE is little, if any, difference in the tastes of negroes and white persons so far as colors are concerned, as determined in tests made recently by Miss Florence Mercer of Texas Women’s College. Ex- amining more than 1000 negroes in Texas public schools, she found that children in the first and second grades preferred red, with blue, green, and violet following in order. This preference changed through the grades until the eighth-grade pupils named blue as their favorite color with red liked least of all. White school children tested showed the same results. Sisters Talk to Each Other across 150 Miles of Sea A WOMAN on an Atlantic liner calle up her sister on another ship 1) miles away, recently, and the two carrie on a conversation lasting eight minute, This was the first trial of a new marvel wireless telephone invented in Germany that can be used either between two ships or between a ship and land. Previously, messages could be spoken only one way over wireless telephone, Only when the speaker had finished ani} the receiving antennae had been switched on, could a person at the other end reply, Now messages may be spoken both ways simultaneously and interchangeably. Home Fire-Gong Gives Alarm at 120 Degrees of Heat HIS littiec ms mechanical . device requires no attention, and has no electrical connections. It is a fire alarm for the home. When the temperature in its vicinity is raised to 120 degrees, a fuse melts and re- leases the small gong, which rings for some time. Showing key that winds fire alarm Pliers with Three Grips 7t IS said that these novel pliers can exert more gripping force on odd shaped surfaces than is obtainable with any othe type of hand tool. A combination d geared and cam leverage is responsible for this strength. The pliers has a special pipe jaw and a round-nosed jaw that ca be substituted instantly for the standard jaw for certain kinds of work. Pliers grip nut with unusual strength

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October, 1% VOod art, of rkable bes > work most Came ard wood 4 ith his wo, 4 years a ned through, tion when A atter Chime Park Avenye ; of John p. P Cathedry n New York . Other f Sea ¢ liner callej 1er ship 15) e two carried ght minute. 'W Marvel—y in Germany en. two ships d be spoken s telephones, finished and | een switched er end reply, n. both ways igeably, es Alarm Heat zy key that ire alarm Grips el pliers can yn. odd shaped ith any othe mbination d esponsible for has a special jaw that can the standard il strength October, 1925 Ingenious Handkerchief-Cutter N AUTOMATIC handkerchief-cutter, taking up only 15 A square feet of floor space, less than a tenth needed for the ordinary machine used for this purpose, is the invention of For half a century the handkerchief industry has been seeking to perfect a small Max Schleifer of Newark, N. J. practical machine of this type. The new machine will measure, cut, assemble, and count 200 dozen handkerchiefs an hour, 50 dozen more than the It stops automatically if the supply of material runs out or defects occur in the material. matic action enables one boy to operate three machines. Any size handkerchief from six to 20 inches square may be cut. The machine rollers adjust the material so that the machine is said to cut straighter lines than a man can, using a machines now in use. knife. POPULAR SCIENCE MONTHLY 57 This auto- RECENT researches with fowls have shown that the quantity of grit carried ordinarily in the gizzard of a chicken is sufficient for a year’s use, supposing the chicken could get no more. Machine measures, cuts, assembles, and counts handkerchiefs American Establishes Figures for Earth’s Diameters N AMERICAN scientist has deter- mined the earth’s diameters so ac- curately that his figures have been adopted by all countries. Director John F. Hayford, head of Northwestern Uni- versity College of Engineering at Chicago, is responsible for this triumph. The diameter is 7,926,678 miles at the equator, while the diameter from pole to pole is 7,899,964 miles, proving the earth to be a sphere flattened at the poles. Director Hayford’s figures will be the basis of every boundary survey in the world in the future. New Safety Door Lock Is Made without Use of Springs NEWspring- less device keeps a door locked automati- cally. The door can be opened from the inside by lifting a bar- rel-shaped piece that slides on the handle. This is loaded, keeping the bolt shot. A simple key locks the bolt. Ordinary key lifts the safety bolt Improved Clawhammer Ax Has Many Uses por the farm, camp, or store a handy new tool is a clawhammer ax. The claw is for pulling nails or for prying open boxes or crates. . The ax head may be used as a hammer or for pulling staples. The ax is forged solid and a wooden grip riveted securely to it so there is no danger of the head’s fly- ing off. The tool weighs only 28 ounces. How the handle is riveted to the ax This ingenious roller for turf tennis-courts, driven by pedals like a bicycle, is so geared that a woman can manipulate it easily How the English Roll Their Lawns and Tennis-Courts HEN aturf tennis-court needs rolling, every fellow tries to shift the job to another. It’s no fun, but real work, push- ing a roller. A machine has been invented recently in England, that may induce even the girls to take a turn at rolling. It is a combination bicycle-roller op- erated by pedaling. It is so geared that the effort ordinarily spent in running a bicycle pushes the machine about the court or lawn. High-Pressure, Hot-Air Fan Dries Hay in Eight Hours FEW months ago POPULAR SCIENCE MONTHLY described a method that English farmers were using to dry hay artificially in the fields. Now the Uni- versity of Wisconsin, on its experimental farm, is demonstrating a similar hot-air drying process. By means of a high-pressure hot-air fan, new-mown hay was ready for baling eight hours after raking. Ordinarily, it would have taken two or three weeks of field drying, and the owner would have had to run the risk of moisture, damage, and pests. ‘Twelve loads can be handled on the drying rack at one time. Simple Distress Signal Code for Hunters and Explorers zx SPORTSMAN and big-game hunter, J. Allen Barrett, of Lykens, Pa., has copyrighted a unique idea for a national code of distress signals for persons who may be lost, injured, or in need of assistance while traveling or hunting in sparsely settled regions. Revolver shots should be used for the signals, but the victim could shout, call, or whistle them. The chief requisite would be to have the code widely under- stood. The code follows: Tosignify “‘lost,’’ two shots quick; wait; one shot. “Injured,” three shots quick; wait; one shot. “Sick,” four shots quick; wait; one shot. “Help,’”’ two shots quick; wait; two shots. Rescuers answer, using the same number of shots, but in reverse order. The answer to “‘lost,”’ for example, is one shot; wait; two shots quick. How Much Do YOU Know about Science? HE following questions are the kind that POPULAR SCIENCE MONTHLY receives daily. Look them over and see how many of them you can answer. Now turn to page 171 and see what per- centage of the 12 questions you were able to answer correctly. 1. What colors the eyes? 2. Why does hot iron glow? 3. Why do we sometimes see a double image reflected in a window? 4. What causes quicksand? 5. Why must you use direct current in charging a storage battery? 6. Does the sun actually draw up water? 7. Why does space outside the earth remain cold, although the sun is shining through? 8. What are comets? 9. If the earth hit a comet, would there be any damage? 10. Why is it that a hurt received while you are excited is sel- dom felt until afterward? 11. What produced the Grand Canyon? 12. Why does a driftwood fire burn with such varied colors? ——————————————— en a ET. eT ne nae We ar ere es

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er

HIS is the time of year when thou- sands of men and boys are turning from outdoor sports to consider the problem of what radio set to build. Large numbers of these already are radio fans. They have, perhaps, built several dif- ferent radio receivers, and now they wish to rebuild their old sets or make up entirely new outfits in order to improve the distance or quality of their radio reception. There are, also, many men to whom radio is still new and strange as far as the actual construction of a radio outfit is concerned. On the surface the problem of what set to build seems simple enough, but un- fortunately there are a number of factors to be taken into consideration which have an important bearing on whether the finished radio receiver, as constructed, will give the builder the type of service he expects. Take, for instance, two typical cases. Fig. 1. Complete PopuLar SciENCE MONTHLY four-tube receiver—ideal for the fan who has had some experience in radio construction

SE & distant stations. ieee See Re ae ae | . | 4] ANT GRD. -A +A -B +45 +90 =3 -43 CG BATTERY RECEIVER that will give perfect satisfaction to one of these men may, conceivably, be of no use to the other. And there are still other considerations if success is to be assured. Ask yourself these questions: Is recep- tion. particularly good or bad in my vicinity? Is a long, high out- door antenna possible, or must I depend on a short indoor one? Have I sufficient me- Fig. 3. above.

showing layout of parts and wiring.

time it is so efficient and gives such good results in the reception of distant

Rear view of the four-tube receiver, described in detail in our July issue, The complete wiring diagram appears This set gives maximum long-distance reception with fine selectivity stations on the head phones, that it is ideal also for the man who does not wish to go to the expense of more than one tube. Here is what one of our readers in Providence, R.L., writes us about this set: “T have constructed the long-distance radio set that was described in the May number of POPULAR SCIENCE MONTHLY and feel highly grati- fied with results. It may interest you’ to know the stations I

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r, 1925 ig and ruction ere re- hat we - again, ing the ou will dapted strated ge (de- CIENCE own in simple, many d, con- wound ‘andard xcellent rly free dio-fre- shrough egener- almost ‘illation ptible quality. nplicity his re- he man uild his he same nt and sults in distant phones, for the wish to of more > of our fe, R.I,, , set: cted the set that he May >OPULAR ONTHLY ly grati- lis. It you: to ations I October, 1925 he first few nights that I used the set ane AP. WEEI,WQJ,CNRO, WLW, WLIT, WTAM, WGY, WBZ, WSAI, WGBS, WAHG, KDKA, and _ several ay 0 this is what another readerin Jersey City, N.J., writes about the one-tube set: “The most pleasant feature of this circuit is that there seemed to be none of the terrific squealing or re-radiation generally found on the usual regenerative set. I might say that I have experimented with different types of regenerative outfits, but I heartily endcrse this one to beat them all.”’ Another fan in Toronto, Canada, writes: “T have completed your one-tube receiver as described in the May issue and have al- ready received 55 different stations.” HILE some of our readers have writ- ten that they have obtained loud- speaker volume with the one-tube set on local stations, such results can be obtained with one tube only when the broadcasting station is less than five miles away and the receiver is connected with a good outdoor antenna. The logical way to obtain loud- speaker volume is to build a good audio amplifier and connect it with the one-tube receiver. Such an amplifier is illustrated in Fig. 4 (described completely in POPULAR ScIENCE MONTHLY for June, 1925, and shown in detail in Blueprint No. 42). Large numbers of radio fans who built the one-tube receiver since have added the amplifier. A radio constructor from Los Angeles, Calif., writes: “IT made the one-tube set you published in the May issue and will say it is the best one-tube set I have met with and now I want to make the coupled resistance amplifier and will ask you where the variable resistance unit for panel mount- ing is to be had.”’ POPULAR SCIENCE MONTHLY Blueprints Available ETAILED working blue- prints for the construc- tion of the three radio units discussed on these pages are available, and will be found listed among the Poputar Sci- ENCE Montuiy blueprints on page 87 of this issue. Blue- print No. 41 is for the one-tube receiver shown in Fig. 5; No. 42 for the amplifier unit shown in Fig. 4; No. 43 for the four-tube receiver shown in Fig. 3. all the connections are made correctly. When the one-tube receiver and the audio amplifier are combined, as shown in Fig. 2, at top of previous page, they will bring in stations and put them on the loudspeaker in a way that will satisfy most radio fans completely. This is true only when a good outdoor antenna can be used. ANY readers have asked what ad- vantage there would be in building the four-tube receiver illustrated in Figs. 1 and 3 (described completely in POPULAR ScIENCE MONTHLY for July, 1925, and shown in detail in Blueprint No. 43). They wanttoknow why theyshould build this set if practically the same results can be obtained by combining the one-tube receiver with the three-tube amplifier unit. This amplifier unit has three features of particular impor- tance: First, it is ex- tremely easy to as- semble and wire. 59 The answer is that the four-tube receiver of Blueprint No. 43 is more sen- sitive and more selective. This means that, other conditions being equal, the four-tube outfit will bring in stations from a greater distance and do a better job of cutting out local interference. Ifthe radio fan finds that these two qualities are needed to a greater degree in order to give him the kind of radio reception he wants, then the four-tube receiver is distinctly worth while. On the other hand, the four-tube outfit is not quite as easy to build and get going as the simple one-tube receiver plus the amplifier. ‘Ta beginner at radio construction, therefore, should tacklethe one-tubeset first. Then, if he wants loudspeaker re- sults, he can add the audio amplifier. These two units also can be combined on one 7-by-24-inch panel. In fact, if the radio fan expects, ultimately, to add the amplifier, it is a good idea to make up the one-tube receiver at one end of a 7-by-24- inch panel and purchase the additional parts for the amplifier later. The wiring diagram of these two units that appear with Figs.4 and 5,shows just how to con- nect them properly. Note that seven binding posts are shown with the wiring of the outfit in solid black lines. The battery wiring of the amplifier unit, when made up separately, appears in dotted lines. A vertical dotted line shows the separation of the two units. Many letters have been received from radio fans who own a pair of .0005-mfd. (23-plate) variable condensers, requesting information as to whether these conden- sers could be used in the one-tube outfit in place of the .00025-mfd. (13-plate) con- densers specified. Second, it repro- duces with remark- the 68 specified. De- pending on the mini- O This change is entirely practical. You must, however, QS cut down the num- ber of turns in coil B c rs of theone-tubeset to about 50 instead of } able quality and ——/] | To 7) Se = a clearness, and third, it will not squeal or ANT. GRD. -A howl, provided that 2e 3] nl st 6 tA ete mum capacity of jo----7----4 eet 22% TO 45 VOLTS “| thelargercondensers used, it also may be +B 90 VOLTS (Continued on page 172) This wiring diagram shows how the one-tube receiver and amplifier unit bélow are combined Fig. 4. Layout of parts and wiring for the three-stage amplifier unit described in our June issue, which the beginner can construct easily and add to the one-tube receiver shown in Fig. 5. In the combined wiring diagram above, this unit is shown at the right to build. Fig. 5. Arrangement of parts for the one-tube long-distance re- ceiver described in our May issue—a set simple for the beginner In the wiring diagram this unit is shown at the left of the dotted line. Blueprints for both units are available

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New Life for Your Radio Tubes POPULAR SCIENCE MONTHLY October, 1995 Remarkable Tests by Popular Science Institute of Standards Show How Worn-Out Filaments Can Be Rejuvenated ADIO vacuum tubes always seem to R fail when least expected. A favorite time, apparently, for a tube to burn out or go dead is when you are trying to demonstrate the remarkable qualities of your radio set to some friend. The music starts off with a grand flourish and then suddenly stops completely or fades nearly away. A vacuum tube that has burned out is beyond recall, of course, but thousands of radio fans do not know that vacuum tubes that have gone dead may be revived. This applies both to tubes that have worn out in service and to tubes that have become paralyzed through the use of too high B-battery voltage or from burning them too brightly in an effort to increase the volume. Practically all the standard vacu- um tubes are what the English call “dull emitters.’”’ In other words, the filaments of modern tubes are coated with a substance that gives oft a plentiful supply of electrons when heated to a temperature just beyond the dull red point. This ma- terial exists on the surface of the fila- ment as anexceedingly thin layer and if the tube is forced beyond the prop- er limits, the material is exhaust- ed faster than it can be replaced from within the filament itself. CURIOUSLY enough, the way to give your tubes new life is to force them—sort of a ‘‘fighting fire with fire’ proposition. The forc- ‘ng process, however, is applied to the filament alone, and the B bat- tery must be disconnected entirely. In theory, at least, the way to re- vive radio tubes is to heat the fila- ment to a temperature considerably above the normal. This excess heat appears to have the effect of forcing more of the material to the surface; and since the B battery is disconnected, the material is not used up and accumulates where it can be of use when the tube again is put back in service. Obviously, no radio tube will last for- ever. Some tubes will stand the rejuve- nation process several times, others only _once or twice; but it is safe to estimate that the average life of a modern vacuum tube can be prolonged greatly. There are three ways in which the coat- ing on the filament can be renewed. To determine the relative effectiveness of these various methods, the Popular Science Institute of Standards Radio Laboratory has just concluded a series of important tests. The three possible methods are these: 1. Operate the vacuum-tube filament at normal rated voltage for several hours with the B battery disconnected. 2. The use of a device designed espe- cially for the purpose. It consists, essen- By Eugene Bruyning Member of the Staff of the Popular Science Institute ot Standzrds tially, of an alternating-current trans- former arranged so that a pressure of 17 volts may be applied to the filament of the standard storage-battery tube. The filament is operated at this voltage for 45 seconds, then a switch is thrown that con- nects the filament with another tap on the transformer, giving eight voits. At this B_ battery was connected. In other words, we put the tubes in such condition that they were of no further use for radio either as detectors or amplifiers. One of these two tubes then was treateq by the first method. After an hour op two we found that it was restored to the point where the plate current was 59 milliamperes, sufficient for radio work, but was not quite as good as new. "THE other tube was treated by the second method, using a standard tube rejuvenator. After treatment the plate current was 8.4 milliamperes—just g shade better than new. This test, with several others, proved conclusively that paralyzed radio vacuum tubes could be restored to use fuiness. Next we wanted to see what the rejuvenation process could do for tubes that just naturally had given out through long service in a radio receiver. In the continual testing of re ceivers, loudspeakers, and other radio apparatus at the Institute laboratory, tubes often are wom out completely in a few weeks ora month, : We took four of these “dead” tubes and treated one by the first method, another by the second, The remaining two tubes were treated by the third method. All the tubes came back to life. They were equally good except the one treated by the first method. This one did not show up quite so well, CROSS- SEGTION OF FILAMENT ‘THESE tests show that adding life to your radio tubes by the rejuvenation process is a distinctly practical and money-saving process. A comparison of our results would indicate that the use of a special alternating-current tube rejuvena- How Vacuum Tubes Are Rejuvenated This diagram of the working parts of a radio tube shows how the filament is surrounded by the grid and the plate. When the filament is heated carefully to a temperature higher than normal, the material that gives off electrons is forced to the surface as indicated by the arrows inthe insec, The B battery must be disconnected voltage the tube is allowed to burn for 10 minutes. This device operates from the electric-light socket. 3. The use of batteries to operate the filament for 45 seconds at from 12 to 17 volts, followed by 10 minutes at from six to eight volts. To start with, in the Institute labora- tory tests, we took two new standard storage-battery tubes and paralyzed them so that the plate current on 90 volts with zero grid potential dropped from 7.5 to .1 milliamperes. This was done by apply- ing a very high filament voltage while the tor is, perhaps, the most practical way for the average radio fan. Equally good results can be obtained by use of direct current from batteries, but most radio fans have no batteries available that will give the requisite voltages. Then, too, there is always the chance of burn- ing out your tubes if you do not happen to hit the right combination: an accident which is not likely to happen with the special devices. In addition to our experiments with standard storage-battery tubes, we also tried out the effect of rejuvenation on three-volt type dry-cell tubes. The results were substantially the same as for storage-battery tubes. Of course the voltages applied to the filaments of dry- cell tubes were considerably lower than for storage-battery tubes. Nine volts, for instance, is about the right amount for tubes of the three-volt type, with from three to four volts during second period.

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tober, 1925 CS ds In other | Condition e for radio vas treated n hour or red to the t was §2 » work, but ed by the standard itment the res—just a rs, proved lio vacuum od to use e what the uld do for r had given > in a radio ting of re and other e Institute 1 are worm weeks or a ese “dead” by the first she second, tubes were tthod. All life. They pt the one thod. This lite so well, hat adding ibes by the a distinctly ‘ing process. esults would of a special e rejuvena- st practical n. Equally l by use of 3, but most vailable that ges. Then, ice of burn- not happen an accident on with the iments with es, we also venation on bes. The - same as for course the ents of dry- lower than Nine volts, t amount for », with from cond period. October, 1925 POPULAR SCIENCE MONTHLY Newest /nventions and Oddities in Radio Percolator Tops for Insulators Here are the lead-in in- sulators used at one of the New York City broadcasting stations. They are made of glass. Two are used for each wire, one inside and one outside, held in place by a long brass bolt that provides a path for the current Receiver Uses House Current Benjamin F. Miessner, well-known radio engineer of New York City, has completed the development of a remarkable new receiver that runs from any electric-light socket. No A or B batteries are needed for this College Students Make Vacuum Tubes The laboratories of Cornell are so complete that the students are able to construct even the vacuum tubes used in their radio work and experiments. The illustration shows Profes- sor B. R. Northrop demonstrating the blowing apparatus The Man Who Gave Us the Neutrodyne Professor L. A. Hazeltine, the man who discovered the principle of the neutrodyne receiver, is the head of the Depart- ment of Electrical Engineering at Stevens Institute of Tech- nology. It is said that Professor Hazeltine made his im- portant discovery entirely by mathematical deduction. The Principle of the neutrodyne as developed by Professor Hazel- tine is to.use a small adjustable capacity arranged in the circuit in such a way that it balances the internal capacity of Unbreakable Tubes Here is Herbert H. Metcalfe demonstrating a new vacuum tube so tough that even a sharp blow will not break the filament. These tubes can be dropped to the floor without any injury Table Loudspeaker It is possible, as shown at left, to build a practical and satisfactory radio table-talker out of the frame and pedestal of an old electric fan. The ventilating holes in the frame serve as open- the tube elements and thus prevents the tube from oscillating ings for the incoming sound

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62 Fig. 1. The sim- plest possible ar- rangement for hooking up a storage A-bat- tery charger Sa How to POPULAR SCIENCE MONTHLY Te \ . : | in SS | (oy MAT 5 Charge Your Radio Batteries Simple Methods of Installation that Will Save Time and Trouble By John Carr HE trouble and inconvenience of charging radio storage batteries has been greatly exaggerated. Of course, in the days before efficient home chargers were available, the sight of a neighboring radio fan laboriously strug- gling down the street with 100 pounds or so of battery on his way to a battery service station was enough to deter almost anybody from buying a radio set. But carrying your storage battery to the nearest garage or service station no longer is necessary. Batteries can be charged at home easily, simply, and cheaply. The only prerequisite is that your home be wired for electricity. Since perhaps 90 per cent of the homes in this country that are wired for elec- tricity are supplied with alternating cur- rent, methods for charging storage bat- teries using this type of current will be discussed in this article. TO RADIO SET DRDT. iam SWITCHI"/ 77 y/ a) VIBRATOR-TYPE " STORAGE CHARGER BATTERY Fig. 2. The correct circuit to use with the older types of bulb chargers and with all types of chargers employing a vibrator Storage batteries produce perfectly uni- form direct current. Consequently they must be charged by means of a direct current, although the charging current need not be uniform in character. Alter- nating current, as supplied to your home over the electric-light wires, cannot be used. Although there is no essential difference in the kind of current needed to charge storage A batteries as compared with that needed for storage B batteries, there is considerable difference in the volume of current and the pressure at which it must be supplied to the two types of batteries. A batteries need large volume at low pres- sure, while B batteries can be charged only with a small volume of current at much higher pressure. iT HRBE are on the market at present three distinct types of A-battery chargers. In each a transformer is used to step down the 110-volt lighting current to a lower voltage suitable for A-battery charging. One type uses a special kind of vacuum tube to rectify this lower voltage current before sending it through the storage battery. Another rectifies with an electrolytic cell, and the third uses a vibrating contact arm which is so made that it swings in time with the 60-cycle alternating current. All three types will give good service if properly constructed. The proper method of connecting the charger with your A battery depends, of course, on the type of charger and the internal connections of the receiver. This is true only when you make a permanent installation controlled by switches ar- ranged so that it is only a matter of throwing a switch to put your battery on charge. With some types of chargers a very simple switch system will give satis- October, 1925 faction, while the same system, used With another charger, may result in burni out your fuses or blowing out the tubes in the receiver. In addition to this possibility, the prob. lem of arranging a hook-up for the A. battery charger is complicated further by the fact that several types of battery chargers are made to charge storage B batteries as well as A batteries, ° FIGURE 1 shows the simplest possible arrangement. It will work perfectly with the electrolytic type of A-battery charger. It can be used also on the newer bulb-type chargers, which are made g9 that there is no metallic contact between the primary windings of the step-down transformer and the secondary circuits, Figure 2 shows the proper circuit to be used with older types of bulb chargers and all types of chargers employing a vibrator, Figure 3 is a simple hook-up for the new type of bulb chargers, which are arranged to charge both A and B batteries. This circuit will work regardless of whether the minus B-battery connection in your receiver is made to the plus or minus A circuit. Chargers made especially to recharge storage B batteries are available in two forms—the vibrator type and the elec. trolytic cell, as supplied under various (Continued on page 173) Fig. 3. A simple hook-up for the new type of bulb chargers, which are ar- ranged to charge both A and B batteries TO RADIO SET CHARGER D.RD.T. SWITCHES B BATTERY B BATTERY Fig. 4. This srrangement, using two double-pole, double-throw switches, permits disconnecting the B battery from receiver, connecting it with charger, and also arranging the two heives of the battery in parallel for charging

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ber, 1925 yee with urning tubes in she prob- r the A- irther by battery borage B ; possible perfectly \-battery he newer made go between tep-down, circuits, uit to be rgers and vibrator, the new arranged es. This ether the in your minus A recharge le in two the elec. r various SET le new are ar- itteries \DIO SET ‘ >.PD.T. SWITCHES RY ig two vitches, ry from -harger, heives harging October, 1925 POPULAR SCIENCE MONTHLY 63 For Well Kquipped Cars ag Half a Dozen Ingentous yee New Ideas to Increase the Motorist’s Comfort 3 rs ae Mewes " Fe i dea a ee Re : oh a 3 Electric Jack Saves Work Every auto-owner who has had tire trouble on a country road knows that jacking up a heavy car is quite a job. And this is particularly true if the punctured tire is on one of the rear wheels, because of the difficulty of reaching under the car. This in- genious new electric jack makes the auto storage battery do all the work Rubber Skid Chains Save Tires Instead of the usual metal links, the cross pieces of this skid chain are made ofsrubber. Steel side chains hold the rubber cross chains in place. It is claimed the new chain works effectively, except when used on icy streets Mudguard Flag Holder For motorists who like to display flags attached to their cars on na- tional holidays, the device at the left solves the problem simply. It can be clamped to the edge of the mudguard and set to hold the flag in a vertical position. It is padded to protect the car finish A High-Pressure Grease-Gun Sometimes a grease or oil channel be- comes clogged and the 500 pounds pres- sure developed by the ordinary grease- gun fails to clear the obstruction. The device shown at the right boosts the pres- sure up to 5000 pounds, sufficient to force grease through Radiator Cap Includes Clock This unique radiator cap combines three func- tions. It tells the time by means of the clock in the center. A thermometer indicates tempera- ture of water in the radiator. At the left another indicator determines the amount of water inside Spotlight Controlled Inside As the illustration shows, this remarkable spotlight is mounted on the end of a hollow shaft. At the other end of the shaft, inside the car, there is a knob. Moving the knob up and down shifts the position of the spot- light vertically, while horizontal swing is governed by turning the knob on its shaft. The inner shaft is, of course, used to transmit all motion to the spotlight from the knob near the steering-wheel of the car so that there is absolutely no chance for play to develop

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Pc Reveals Some Tire Secrets His Easy Ways to Make Roadside Repairs Save a Lot of Time A Flat Tire—and the Jack Is Missing! Gus sat on a rock and bossed the job while ‘Joe repaired a punctured clincher tire with- out jacking up the wheel. The tire was mended quickly and easily with the aid of nothing but tire irons and a “‘sizzle patch’”’ By Martin Bunn ‘Gr MORNING, Gus—what do you know about real estate?”’ said Joe Clark to his partner, just as the latter was unlocking the door of the Model Garage. “Not a durn thing at this time of day,” Gus growled crossly and a bit sleepily. “Oh! All right, you old grouch!”’ grinned Joe. “I only wanted to tell you chat there’s a house up my way that I want to buy. I thought maybe you’d take a run up there with me and tell me if it’s a bargain.” “Humph!” grunted Gus. “One of those places over on Biddle Avenue, I suppose?” “No, sir!” answered Joe emphatically. “This one is on East Main Street.” “T don’t know anything about those houses,’”’ said Gus, showing a bit more interest. ‘Suppose we take a run up there this afternoon and give it the once over. The kid can take care of the gaso- line pump, and business is slack now anyway.” Along about half-past three Joe sug- gested that it was time to start,-and the two men climbed into Joe’s flivver and started off, leaving Bill, the kid who did odd jobs around the garage, standing importantly beside the gasoline pump. This was the first time he had been left in charge of the place, and he was as proud as a peacock. POPULAR SCIENCE MONTHLY “‘Gosh!”’ exclaimed Joe, as they rattled down the road. “This boat certainly does steer hard. I can barely keep it on the road.” Gus looked at his partner with a pained expression on his face. “‘Son,’”’ he said, ‘‘as a bookkeeper you are a whiz, but you are surely a dummy about autos. Haven’t you seen that this bus rides as rough as a broncho? I was just waiting for you to notice that your right front tire is almost flat! I suppose it would have to come right off the wheel before you’d get wise.”’ Joe appeared decidedly crestfallen as he stopped the car at the side of the road. And his face registered downright chagrin when he discovered that the jack was missing from the toolkit. ‘Whatever became of that jack, I wonder?”’ he muttered disgustedly. ‘“Now I suppose we will have to run back to the garage on the flat tire and ruin it in the process.”’ G5 meanwhile had been poking around in the toolkit. “Drive back nothing!’’ he said em- phatically. ‘“‘What do you suppose these ‘sizzle patches’ are for, except to repair flat tires with?” “Sure, I know what they are for,”’ said Joe; “but what good are they to us if we have no jack to take off the tire?” “Don’t worry about that,’ replied Gus; ‘just you get behind this bus and push it along slow so I can see if I can locate the hole.”’ . Gus kept a sharp watch on the slowly revolving front tire and his keen eyes soon spotted the head of what turned out to be October, 1925 an extra long carpet tack in the rubber. “Now,”’ he said, “this is your car and] am going to light my pipe and boss the job while you do all the work. Get out your tire irons, the clamp, and sizzle patches,” b igta did as directed, for he long since had learned that when Gus said he knew how a thing could be done, he was pretty sure to be right. While he was locating the irons, Gus filled his pipe and settled himself com. fortably on a near-by rock. “Get busy with the irons now and pry off the bead of the tire right where we pulled out the tack and for eight or 10 inches on each side of the puncture, That’s the idea,’’ he nodded, after a few minutes of strenuous work on Joe’s part. ‘‘Now pull out the tube and find the hole,” Joe meekly followed directions and when he had found the puncture in the tube, he proceeded to scrub the surface of the rubber surrounding it with a rag dipped in gasoline from the tank, tore off the protecting paper from the uncured rubber on the bottom of the tin sizzle patch, clamped it firmly in place over the hole, and finally touched a match toa corner of the brown cardboard-like sub- stance, which immediately started to sizzle and fume like a firecracker fuse. US settled back to enjoy his pipe while the patch was cooling. “In five minutes, or thereabouts, we should be on our way,’’ he said. ‘And you will kindly notice, Joe, that we did not need the jack after all. Of course, you couldn’t do that with a straight side tire, but it’s a handy kink to know if you own a light ear fitted with clincher tires.” After waiting the prescribed time, Joe pushed the tube back into the shoe, pried the bead on the rim, pumped up the tire, (Continued on page 66) A Sure Guide for Parking To avoid scraping tires against the curb in parking, Joe invented an ingenious scheme for gaging distance. With his car parked correctly, he got in the driver’s seat and observed just where the curb line appeared in relation to the top of the radiator. After that it was a simple matter to judge the distance from the curb by repeating the same line-up when he drew up to the edge

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ber, 1925 . FREE-—Valuable Instruction im Book on Wood Finishing

POPULAR SCIENCE MONTHLY 65

aa It tells how inexpensive soft woods H 8 a job such as pine, cypress, birch, fir, etc., i ou r . atches,” may be finished so they areas beautiful since had and artistic as expensive hard woods. he k , 2s peal Tells how you can easily and eco- ons, Gus nomically put furniture, floors and elt woodwork in perfect condition. How anda to finish wood in beautiful stained Where w : ° ‘ht or 10 effects with Johnson’s Wood Dye ter a a and in up-to-date enamel effects with nee Johnson’s Enamel. ions and ‘ re in the , meee ice How to Get it—FREE % tore off Ask your best paint or hardware dealer Pages for a FREE copy of the Johnson 25c Book in sizzle ena aha > over the on Wood Finishing. If your dealer cannot on furnish this Book—mail the coupon to us, tarted to giving the name of your dealer, and we will er fuse. gladly send you a copy free and postpaid. Saas pipe This book is the work of experts—pro- bouts, we fusely illustrated in color. d. “And t we did =! JOHNSON’S WOOD DYE aight side 10w if you her tires.” » tone, Penetrating > the tag Dark Oak Light Oak Walnut Fumed Oak Golden Oak Bog Oak Dark Mahogany Mission Oak Flemish Oak Light Mahogany Weathered Oak Early English

Johnson’s Wood Dye is very simple to apply—it Johnson’s Wood Dye is a dye in every sense of the

e curb in s scheme r parked seat and appeared yr. After udge the ating the the edge

goes on easily and quickly without a lap or a streak. Dries in four hours and will not rub off or smudge —penetrates deeply, bringing out the beauty of the grain without raising it in the slightest. All shades of Johnson’s Wood Dye may be easily lightened or darkened. The Symbol of the Specialist The sign at the left distinguishes the Wood Finishing Specialist from the ordi- nary paint store. All stores displaying this sign carry a full line of Johnson’s Ar- tistic Interior Wood Finishes. They will gladly give you a FREE copy of the Johnson 25c Book on Wood Finishing and are competent to answer questions and give advice on the proper finishing of wood. Ask them to show you wood panels finished the “‘Johnson way”’.

we - ened ’ ess a” SERVICE DEPARTMENT. Can Joon ARTISTIC wooD FINISHES word. It penetrates so deeply that the natural color of the wood is not disclosed. Like most first class products Johnson’s Wood Dye answers one pur- pose only— it dyes the wood; a finish must be ap- plied over it—we recommend Johnson’s Varnishes or Johnson’s Polishing Wax. Th. Gh UR Th Gh HA A TA Gh. GA G. TT TA TA VR A A § S.C. JOHNSON & SON, Dept. P. S.10, “The Wood Finishing Authorities’’ RACINE, WIS. Please send me free and postpaid a copy of the Johnson 25c Instruc- 4 tion Book on Wood Finishing and Home Beautifying, ‘“The Proper TA. : Treatment for Floors, Woodwork and Furniture.’’ ] De Ne Re ee a Fy Address.................. City mtd Stages... 6c... kee Re DG RTOL GROG oa ac i ci ncn ns sacnsca casa potagseneresgs 0, <canengitcee ee eS ee ee © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See paze 6. ee eee

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66 (Continued from page 64) and they proceeded on their journey. Soon there came the sound of a motor horn. Gus looked around to see who it was trying to pass. “Tt’s old Mr. Conklin,” he said. ‘Give him plenty of room. The old duffer can’t see well, and he’s liable to tear off a ~ mudguard for you.” Joe pulled over close to the edge of the road and Conklin rolled by. “Look!’”? exclaimed Joe. flat tire too!” “Give her the juice!’’ Gus called out sharply. ‘“That’s a new tire he bought from us. We can’t let him ruin it.” “He has a Jo opened the throttle and the little car quickly picked up speed. The chase scarcely had begun, though, when there came a resounding report from the car ahead. “Now I suppose he'll . blame us for selling him a defective tire,’’ Gus grunted. “Well, pull in behind him. We might as well take our medicine.” But this time, both Gus and Joe were wrong. The soft tire had not blown out. It was, instead, an old tire on the right front wheel of Conklin’s car that finally had let go. Conklin was climbing out as the little car pulled in behind him. ‘Hello,’ he hailed them. “You arrived just in time. You can help me change tires.”’ “That’s why we were trailing you,”’ said Gus. “How did you know I was going to have a blow- out?” asked the other in surprise. “T didn’t, but your left rear tire is almost flat. We were trying to overtake and warn you when the other one surprised us by bi: wing out.” Conklin swung around with a grunt. “More bad luck,” he said gloomily. “Two flat tires and only onespare. What am I going to do about it?”’ “Nothing to it,” said Gus. ‘‘Put the spare on in place of the blown-out front shoe, and we'll fix this soft one for you. Got a jack in your toolkit?” its rim. (CONKLIN produced a jack and a couple of spindly little tire irons about eight inches long. Gus looked disgustedly at the tire irons. ‘“‘There’s a real tire The extra leverage was also a decided advantage POPULAR SCIENCE MONTHLY —the blowout came right where the side wall of the tire was worn nearly through.” “By jinks, you’re right,’ exclaimed Conklin, bending down and peering over the rims of his glasses at the ugly hole in the side of the casing. ‘‘You know, I never can tell when the wheels are close to the curb, and what with all these new- fangled regulations about parking close to the curb, the only way I can be sure is to edge in till I feel the tire scrape.” ““Yes,’’ Gus replied, “‘lots of people have the same trouble. Even Joe, here, wore out a couple of front shoes before he in- vented a scheme that works fine. Tell him about it, Joe.”’ “Well, as Gus says, Mr. Conklin,” ex- plained Joe, “I couldn’t seem to gage the distance from the curb to the tires at all, but finally I hit on a scheme that works out fine. First, you park your car care- fully, getting out and ob- serving its distance from the curb and moving closer or farther away until it’s just right. Then you get into the driver’s seat, look over the front of the radiator to the point where the street touches the curb and notice just where this line appears in relation to the top of the radiator. After that, all you have to do to park the ear at any: time is to be sure that you are in the same driving position and watch the curb line and the radiator until they line up right.”’ “Sounds like a good scheme,” said Conklin. al try at Out.” A Spring-Leaf Tire Iron Using an old spring leaf as a tire iron, it was a _ simple matter for Joe to remove the tire of Mr. Conklin’s car from B* THIS time, Gus had the blown-out tire off the wheel, and had sub- stituted the spare. Joe tightened up the rim bolts and then jacked up the rear wheel. ‘“Must be a slow leak,”’ Gus growled dis- gustedly, as he carefully looked over the tread of the soft rear tire without finding any visible cut or nail in its corrugated surface. With a hammer, he pounged the lock on the rim around to the open position and then, raising the tire high in the air, he brought it down on the ground with a thump. He madesure, of course, that the point of impact was about six inches from the break in the rim and on the side, opposite the locking lever. The jar snapped the rim open and it was then a October, 1925 One Way to Find a Siow Leak “I didn’t see it,’’ said Gus. “I could find it just as well in the dark. The eye isa sen- sitive organ, and mine felt the small stream of air that was coming out of the tiny hole” simple matter for Joe to pry the tire off ° the rim with the erstwhile but treasured spring leaf. “How are you going to find the leak?” Conklin questioned, as Gus pulled the tube out of the casing. “‘We haven’t any water to put it in and watch for the bubbles.” “That’s easy,” said Gus smiling; “just watch.” HE PUMPED up the tube to a diame- ter considerably larger than normal, and then passed the tube, inch by inch, close to his eyes. “There!” he called out “The hole is right here.’’ “T wish I had eyes like that,” said Conklin admiringly, “‘I never could see a hole as small as that. I even can’t see it now you have pointed it out to me.” “T didn’t see it either,” said Gus. “I could have found it just as well in the dark. The eye is a pretty sensitive organ, and mine felt the small stream of air that was coming out of the hole. Blowing up the tube till it was good and fat stretched the hole so that a lot more air came out than when it was in the tire.” Gus pulled a stubby indelible pencil out of his pocket and carefully ringed the hole on the tube so that he would not lose track of its location. Then the clamp and sizzle patches were brought out again and shortly thereafter Conklin’s car was resting on four inflated tires. suddenly, a EVER so much obliged,’ said Conklin gratefully, as he climbed in behind the wheel. ‘‘Have another new tire ready for me tomorrow. I’ll stop in some time in the morning. “By the way,” he went on, ‘I’ve been thinking of fitting the old bus with balloon tires. What do you iron,” he said, holding up a think of the idea?” two-foot length of spring leaf. ‘“‘You can’t do good work on tires without at least one real man-sized iron. ‘Look here, Mr. Conklin,”’ Gus continued, as he ex- amined the front tire, ‘‘this tire is junk. You have got pretty good mileage out of it, judging from the looks of the tread; but you certainly knocked off at least a thou- sand miles by scraping against Let Gus and Joe Help You! HE Model Garage is a real place, and Gus Wilson and Joe Clark are real men, although, of course, fictitious names have been used to.dis- guise the identity of the two veteran automobile men in Mr. Bunn’s fascinating series of stories. Mr. Bunn assures us that Gus and Joe will be glad to answer any questions addressed to them in care of the Automobile Editor. “T don’t think much of it,” answered Gus candidly. “The tires you have are over- size, and your car isn’t heavy, so you can run the tires at. fairly low pressure without injuring them. A whole set of balloon tires with new wheels for them would cost you quite a bit of cash. And, besides, the slight improvement in the riding quality would not be worth the curbstone so much. See, (Continued on page 174)

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ober, 1925 2. eak uld find is @ sen- stream iy hole” e tire off | treasured he leak?” ulled the ven’t any _ for the - a diame- 1 normal, by inch, suddenly, at,” said uld see a n’t see it ne.” Gus. ‘§ ll in the sensitive tream of she hole. rood and lot more the tire.” encil out l the hole not lose 1e clamp out again lin’s car d,”’ said imbed in ther new ll stop in [’ve been us with t do you ch of it,” ndidly. are over- ar isn’t run the pressure em. A on tires or them 2 a bit of the slight e riding be worth 174) October, 1925 POPULAR SCIENCE MONrHLY For the man who . Bi Sas > enjoys good tools “The Saw Most Carpenters Use” Here are the things that prove a saw: = Disston D-8. The world’s standard gor all-around work. Disston D-115, the saw for those who want the utmost in finish and service. Se a ica) : ve a Disston D-23. With narrow blade 134"" wide at point, 614" at butt. ASK DISSTON about the saws you need for your work. Balance, hang, easy running— Fast, clean, true cutting— . An edge that holds its keenness— @ Enduring usefulness HESE are the stand- - ards by which Henry Disston judged a saw. The standards to which he him- self made the saws that bore his name. First he improved saw workmanship, making bet- ter -saws with his own hands. Then he trained other men to make them as he did. Then he developed America’s first crucible saw steel—Disston Steel— a steel so strong, tough, springy and hard that no other steel is like it. Eighty-odd years have gone into the improve- ment of Henry Disston’s methods. Sixty-odd into refining his steel. Today the Disston Saw is the saw for the lover of good tools. For the car- penter, the mechanic, the farmer, the householder— For balance; for fast, clean cutting; for lasting keenness; for a lifetime of service. Get your Disston at the nearest hardware store. Test it for these things in your own hands. Henry Disston & Sons, Inc. Philadelphia, U. S. A. Hardware dealers the world around sell Disston Saws, Tools, and Files DISSTON S This se.1 on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. eeeenneneeterteeeees

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Eight Usetul Hints for Autoists Timely Precautions Result in a Smooth-Running Car FTER several years of service, A many automobiles give trouble through overheating. Generally the cause is a clogged radiator and water jacket, although frequently worn rubber hose used to connect the parts of the water circulating system may be to blame. The best way to clean the inside of the radiator and the cylinder water jackets is to flush out the whole system with about five gallons of water in which about a half pound of lye has been dissolved. Fill the radiator with this compound and run the engine until it is hot, then drain the solution off and flush out the radiator several times with fresh water. While you are about it, you may as well clean the cooling fins by squirting water through them with the hose as shown in Fig. 1. Do not direct the water against the radiator from the outside, as it will be sure to get on the car’s ignition system. HEREVER the roads are soft, automobilists are occasionally in difficulty because the car wheels sink so deeply in the mud. It is usually the custom in such localities to carry a block and tackle. Figure 2 shows a simpler POPULAR SCIENCE MONTHLY How to Clean the Radiator Fig. 1. In time, engines become overheated because of a clogged radiator and water jacket. This picture shows how to flush out the cooling fins with fresh water from a hose, the stream being directed outward ~—= FILLING ~ device. It consists of a To Pull Car from Mud wooden trough made of heavy Fig. 2. Wooden trough is a great : help when a car is stuck in the mud as shown will planking. A row of large nails prevents the board from slipping in the soft mud. Wooden cleats should be nailed over the heads of the spikes. They will give traction to the tire and also prevent a puncture. OME automobiles are not fitted with a petcock between the vacuum tank and the main tank, so the only way to get gasoline out is to disconnect the gasoline pipes. This has its disadvantages, for the connection often leaks when it has been replaced. If a piece of rubber tubing is available, the gasoline may be siphoned out. The pipe is pushed in slowly through the filler-cap opening until just a couple of inches remain outside of the tank. Then the outer end of the pipe is folded over against itself and held tightly (as shown in Fig. 3) while the other end is pulled out and put into the container, which should be as fag below the level of the tank as possible. REPAIR, SWEATEDON ISE marks on your work stamp you as a poor mechanic. Always use wooden blocks LEATH I MET RecrEetog" when you clamp A any important é a part. e s pepsin M Figure 4 shows leather sleeve over gas how to make pipe prevents breaks wooden blocks WOODEN GRIPS FOR PISTON RINGS HOLDER FOR REMOVIN WRISTPIN BUSHINGS Wooden Blocks Protect Metal Fig. 4. Vise marks on a car indicate care- lessness. With a set of wooden blocks, pistons, rings, and gears may be supported, surfaces protected, and breakage reduced _ OLD OIL CAN Tightening Battery Terminals and a Trouble Light Fig.6. An ordinary iron washer will tighten up a worn tapered lead plug on cable end connecting with battery terminal. Fig. 7. A discarded oilcan makes a satisfactory trouble-light holder with nozzle removed, a standard socket soldered in, and a bulb added RUBBER TUBE A Gas Siphon Fig. 3. Rubber tubing bent October, 1925 support various parts. Besides protect. ing the surface of the part, the wood supports the metal and eliminates chang of breakage. ‘THE gasoline pipe that leads from the main tank to the carburetor g vacuum tank’should be inspected oeeg. sionally to make sure that it has not loosened. When this happens, the vibra. tion of the automobile results in eop. tinually rubbing the pipe against some part of the car so that the pipe wears thin and a leak develops. For dependable and easy repair, drain the tank or shut off the valve at the tank end of the pipe line and disconnect the pipe. Scrape the surface of the pipe at the thin point where it has chafed through and tin all around the hole with a hot soldering iron. Next, cut a sleeve of thin sheet brass and bend to fit the pipe, Now tin the inside surface of the sleeve, place it over the break, and sweat it in place until the solder has run in between sleeve and pipe. If any part of the car is found rubbing against the pipe, a leak may be avoided by fitting the pipe with a ut leather sleeve wired on, as shown in Fig. 5. siphon gas TH tapered lead plugs on the end of the cables that connect with the storage-battery terminals sometimes become worn. - When this happens, use ordinary iron washers around the nut so that the tapered plug will be pulled tightly into the tapered hole in the battery terminal (as in Fig. 6). AN OLD oilcan will make a good trouble-light holder. The nozzle is discarded and the bottom cut out, so that the edges of the hole are round and smooth. A standard socket is soldered in place, as shown in Fig. 7, with a washer for greater security. IN TIMING the ignition system, it is necessary to determine the piston’s top dead center. A simple and accurate way is to make a test plug of an old spark plug and a piece of brass, as shown in Fig. 8. The brass piece is threaded and OIL-GF after a cup- shaped depres- a sion has been cut a small hole is drilled through the piece, using a No. 50 drill. Place a little cyl- inder oil in the cup and turn the crank slowly. The air in the cylinder will bub- ble up and stop at the top dead center. Piston’s Dead Centef Fig. 8. Spark plug and wire device show pis- ton’s top dead center

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tober, 1925 , 2S protect. the wood ites chanee Is from the uretor op ected occa. it has not , the vibra. ts in con. inst some wears thin pair, drain at the tank ‘onnect the the pipe at fed through with a hot eeve of thin ; the pipe, the sleeve, break, and 2 until the in between the car is against the be avoided ipe with a ired on, as 2ad plugs on the cables ‘age-battery rorn. - When ron washers apered plug tapered hole ; in Fig. 6). ike a good he nozzle is out, so that round and is soldered 7, with a ystem, it is the piston’s y is to make plug anda ‘ig. 8. The

Yead Center yark plug and ce show pis- dead center

POPULAR SCIENCE MONTHLY October, 1925

71

Home Worksho Arthur Wakeling, Editor

ee eran

A New Way to Cover Crack How Ceilings and Walls Can Be Repaired with Wallboard at a Relatively Low Cost By Edwin M. Love S: COSTLY and inconvenient are however, the handy man can make an unsightly room very attractive. And this can be done at little cost and with a minimum of disorder and dirt. There are several varieties of wallboard on the market, but those of fiber con- struction, because of their flexibility and small plastering jobs that the home- owner hesitates to go to the expense of renewing cracked or loosened plaster in his house. By means of wallboard, EQUALLY SPACED WALLBOARD JOINTS CUT INEXPENSIVELY FOR A WALLPAPER FINISH

PANELS ~~ PICTURE MOLD a aie —! tt #ex« <4 = ” i at | AM oe RNS! Pas U a = 1 | i { / a \ \ | hh LL 1 ot. 11BACK BAND ! i is hi ie } t gk it mm \\ ; i | if H \\ 1 ! Hf - Ww ; 1 ots Mit i Ha Wi 4 y Ni } N | at | | V/ H iN 14t l'stupsil = wi ras a wot yr e/ \S : aproli” & 1 \\ ee = Ar iL oi: ft PANEL MOLD: || BASEBOARD \ SSL MMVI i A WWNMMWSSSSSA0 WB SSSS J tif. Y; YY Vhs Va | | | WALLBOARD JOINTS CUTS SSN /.* Ie FLOPS TE @ Barer We Fo POLED \

DECORATIVE STRIPS —__

ALY TELL] _ a | VL MMLC. BACK BAND ws

CASING = & PLASTER~

ISS ess | SSSOOKON SWNT

* BAND ‘ NOTCH EDGE OF STOOL TO ALLOW WALLBOARD TO SLIDE IN BEHIND

TROUT notch sack BaNp PINTO NECK MOLD | | ® WALLBOARD SEAM _ Fig. 2 is a typical wall elevation. Figs. 3, 4, and 5 are details of the trim. Fig. 6 gives molding profiles. Fig. 7 illustrates the base. Fig. 8 shows the end of panel strip ready for joining

ed Plaster Box

Cc 2 a a <

' Fig.1. The 1 by 4in. furring strip is shown at A, the upper cornice member. 4 by 314 in., at B, the side cornice member at C, the picture molding at D, and the wallboard at E lightness, are probably the best for the home mechanic. They usually are made in 4-ft. widths. If the plaster is attached to the lath with fair solidity, as is generally the case, apply the wallboard over it, otherwise remove it to the lath. Much wallboard, especially that of the heavy, plaster type, is applied in such a way that the joints can be filled with a plaster composition and the wall then papered. This is, perhaps, the most inexpensive method, but the seams are apt to show through the wallboard in time. A BETTER method than attempting to paper over the seams is to cover the joints with “batts” or decorative wooden strips to form panels (Fig. 2). Few rooms are so designed in the grouping of door and window openings that the wall and ceiling panels can be arranged symmetrically and still mate with each other. It is best to divide the ceiling evenly into panels, and group the wall panels according to openings, or else make them fit the ceiling panels regard- less of the openings. - Since all wallboard edges must have solid backing, an inexpensive job consists (Continued on page 123)

This month’s Home Workshop will be found on pages 71, 72, 76, to 127, and 131 to 134; The Shipshape Home on pages 128 to 130, and The Better Sho Methods on pages 74 and 135 to 145.

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72 POPULAR SCIENCE MONTHLY October, 1925 Is Your Heating Plant Ready? How to Put It in Shape for the Coming Winter By Lawrence B. Robbins {\ Unless it was removed and cleaned in the spring, take down the smoke pipe, rap it with a stick to loosen the accumulated scale, and then scrape or brush out all the soot The register box of a “‘pipeless’”” furnace is a dust catcher and should be cleaned thoroughly. Small registers and air pipes should be dusted every few years The end of the smoke pipe should not project into the chimney more Any section of the smoke pipe that is badly rust@l or contains holes should be replaced. Wire the smoke pipe securely so that there will be no chance of the joints’ opening At right: Many a firebox is left fuil of ashes through the summer. It must be cleaned out thoroughly so the grates can be inspected Broken asbestos insulation should be patched with a paste of asbestos meal and water Y HAVING your boiler or furnace thoroughly clean, even to the most inaccessible places, you can save anywhere from one-half to four tons of coal a season. It is advisable to dust between the radiator sections and even to remove the outer casing of a hot-air furnace, so that than the width of a single brick Cover steam or hot-water pipes with asbestos paste or cellular insulation the heating surfaces can be well brushed. The cold-air box should be cleaned and the air-inlet screen freed from rubbish. If you have a hot-water or steam plant, drain off the water until it runs clear. If there is much sediment, empty and flush the boiler. A steam boiler should be refilled until Open all clean-out doors and remove soot and scale with a long handled wire brush and a small, flat scraper. A special flue brush can be purchased or a wire handle can be attached to any small bristle or wire brush pee i a ral a I If any of the grate bars are burned or broken, they should be replaced with new ones; not a difficult job the gage is half full with water; in a hot water system, until the gage on the expansion tank shows one-quarter or one-third full. Joints between the castings of the boiler should be pointed when necessary with furnace cement. Examine all con- trol valves, and test the safety valve.

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ove soot rush and ue brush e can be re brush n, they icult job ; ina hot e on the juarter or zs of the necessary .e all con- y valve. October, 1925 POPULAR SCIENCE MUNTHLY 73 WANTED: Men to Keep Pace with R.B.Cook In 1919 R. B. Cook was a book- keeper—holding down a one-track job. In 1923—four years later—he was sales manager of the B. A. Railton Company, Chicago; and ever since that time has successfully directed a sales force of more than seventy salesmen, many of them with twenty years’ experience. “To the casual observer,’’ writes R. A. Railton, General Manager of the B. A. Railton Company, “‘his rise might seem unusually rapid, but we view ic as the natural result of his being prepared for the big oppor- tunity when it came.” CHICAGO Worlds Largest ssTramung institution; The Busine: “Worth More Than $10,000” (—So writes R. B. Cook, the employee) “The advancement I have made during the past five years to my present position as Sales Manager of the B, A, Railton Company was made possible thru your splendid training and the various services which I have used with much profit. Two years ago I wrote you saying that I would not part with the knowledge LaSalle training has brought me for $10,000. To- day I can say that I would not part with it for several times that amount.” — (Signed) R. B. COOK, Chicago. “You Are Rendering Our Organization a Distinct Service” (—So writes R. A. Railton, the employer) “In training a half million men, your institution has made a valuable contri- bution to business. You have added millions to the wealth of the annual earnings of your student members, Their increased productive capacity in turn is adding many millions to the business of the institutions which they serve. I feel that in bringing to our attention a man with the training and capabilities of Mr. Cook, you are rendering our organiza- tion a distinct service.” (Signed) R. A. RAILTON, Chicago. | +1 cath cs 1 | | l | f . Here is the stury of a pace-maker—a man who refused to let handicaps obstruct his prog- tess—a man who acts and makes money by this simple principle: to capitalize his every resource. Handicapped by ill health—which kept him in a hospital during four years of his bbyhood— R. B. Cook, a Chicago man, bridged the gap in his education by day and evening study, which gave him a sound foundation for LaSalle home-study business training. Starting as a bookkeeper, in 1919, he enrolled for LaSalle training in Modern Business Cor- respondence and Practice. “Before I was half way thru my training,’’ writes Mr. Cook, ‘‘I was promoted to Collec- tion Manager, with an increase of 50 per cent in salary. Later I became Credit Manager of another concern. This move was avery decided promotion. ““My next advancement was to the position of Office Manager. In each of these positions I was successful. This fact paved the way to my present position. Two years ago I was offered a post as Assistant Credit Manager with my present concern. Within two years I was made General Sales Manager, which position I now hold.’”’ Five years of consistent progress—that is the record of Mr. Cook, who has recently enrolled for LaSalle training in Business Management. When a young man can advance in four years from a routine job to the position of Sales Manager of one of the big wholesa + houses of Chicago— without any pull except his own initiative—there must be a reason. There is a reason. It’s summed up in the LaSalle salary-doubling plan. What that plan has done for R. B. Cook it can do for any man sincerely ambitious to increase his earnings. Advance, by this Plan, to Bigger Pay! Paragraph by paragraph, line by line, he takes up each assignment, asking himself how he can turn each business principle into profits for his company. Asingle idea—so he writes—which he got from his very first assignment—resulted in savings of many thousands of dollars for his firm, Send for Salary-Doubling Plan You are eager for success. You wish to enjoy the rewards which come inevitably to the man who fits himself for responsibility. But before you can reap those rewards, you must make yourself more profitable to the business which employs you. By no other method can you possibly succeed. Cook’s experience clearly shows the way—a way illuminated by the careers of thousands of LaSalle-trained men. During only six months’ time, for example, as many as 1,248 LaSalle members reported definite salary-increases totalling $1,399,507, an average increase per man of 89 per cent. The details of the LaSalle salary-doubling plan will be sent you for the asking. Whether you adopt the plan or not, the basic information it will place in your hands, without cost, is of very real and definite value. Balance the two minutes that it takes to fill out the coupon against the rewards of asuccess- ful career—then clip and mail the coupon NOW. LASALLE EXTENSION UNIVERSITY [_]Basiness Management: Training for Official, Managerial, Sales and Departmental Executive positions. [Modern Salesmanship: Training for posi- tion as Sales Executive, Salesman, Sales Coach or Trainer, Sales Promotion Manager, Manufacturer’s Agent, Solicitor, and all posi- tionsin retail, wholesale, or specialty selling. Higher Accountancy: Training for posi- tion as Auditor, Comptroller, Certified Public A tant, Cost A tant, ete. [Jesper Bookkeeping: Training for posi- tion as Head Bookkeeper. Os; P. A. Coaching for Advanced Account- Name. Che and Finance: Training for The World’s Largest Business Training Institution —— — — — — — - LLP AND MALL Orr ee LASALLE EXTENSION UNIVERSITY T shall be glad to have details of your salary-doubling plan, together with complete information regarding the opportunities in the business field I have checked below. Also a copy of ‘*Ten Years’ Promotion in One,” all without obligation. [_]Law: Training for Bar; LL.B. Degree. Commercial Law: Reading, Refer- ence and Consultation Service for Busi- neering, etc. ness Men. : F C] ModernForemanshipandProduction Traffic Management — Foreign and Methods: Training for positions in Shop Management, such as that of Superin- tendent, General Foreman, Foreman, Sub-Foreman, etc. Domestic: Training for position as Rail- road or Industrial Traffic Manager, Rate Expert, Freight Solicitor, ete. Railway Station Management: Train- ing for position of Station Accountant, Cashier and Agent, Division Agent, etc. executive positions in Banks and Financial] Institutions. Service, Present Position Dept. 1083-R Industrial Management: Training for positions in Works Management, Production Control, Industrial Engi- Personnel and Employment Man- agement: Training in the position of Personnel Manager, tions Manager, Employment Manager, and positions relating to Employee Chicago Modern Busi- ness Corre- spondence and Practice: Training for position as Sales or Collection rrespondent, Sales Promotion Manager, Mail Sales Manager, Secretary, etc. Business English: Training for Busi- ness Correspondents and Copy Writers. [location oni Spanish: Training for position as Foreign Correspondent with Spanish -speaking countries. Industrial Rela- B~y e- Speaking: Training in the art of forceful, effective speech, for Ministers, Salesmen, Fraternal Leaders, Politicians, Clubmen, etc, Address © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

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pa tea Se RE POPULAR SCIENCE MONTHLY October, 1935 C Better ¢ Shop Methods ai c ~ [IR § By Charles Kugler UGGESTIONS for punch and die making as outlined in this article are the result of the writer’s 30 years’ experience as a mechanic. Some of the kinks, so far as the author knows, have not been published before. In the first part the methods described can be used only in shops that have the proper equipment for this class of work. In the latter part the methods are those useful in shops where the equipment is inadequate or obsolete. The rules to be given are not iron- clad. The author has in mind an average mechanic and an average job. If your shop has a die-filing machine and a vertical shaper, as well as other good tools, and you have to make a punch and die for such a part as the steel stamping \ in. thick, repre- sented by the templet shown in Fig. 1, you can proceed as follows, bearing in mind that this example has been chosen because it allows so many points to be illustrated clearly and not because it represents an economical design from a production standpoint: Fisst, plane or machine the punch, die, stripper, punch pad, and shoe. Grind one side of the punch pad and blue it. If one has not already been provided, make the templet (Fig. 1) and scribe its outline carefully on the blued surface of the punch pad (Fig. 3). Then assemble the four parts as in Fig. 2. Two \%-in. parallels should be placed as shown between the die and shoe for clearance when boring the 1-deg. taper hole in the die. Carefully drill nN Ta . ee Hl Nl | TEMPLET \ 2 unch and Die — Secrets of Success ina Type of Work Machinists now Encounter Frequently and ream dowel-pin holes and drive dowel pins in tight. The work now is ready to be strapped on the faceplate of a lathe for boring out the four l-in. holes, as shown in Fig. 4. Carefully indicate the center punch mark and drill and bore one hole; then remove the punch pad and stripper and make the hole in the die taper 4% deg. on a side. Assemble again and proceed similarly with the other three holes. I remove the punch pad and stripper by prying them apart with a thin chisel without remov- ing the dowel pins or disturbing the set- ting of the work, but other mechanics provide setscrew holes for forcing them off, which lessens any likelihood of the work’s being damaged. Remove the work from the lathe and, after applying a solution of sulphate of copper or blue vitriol on each of the parts, carefully scribe the outline of the templet on them. The filing machine (Fig. 5) is used to saw out the core, leaving about 1/32 in. for machining. Now that the core has been removed from the punch pad, stripper, die, and shoe, assemble these parts again ag jp Fig. 6 and clamp them on the table of the vertical shaper. Carefully line up the outline on the stripper with the ways of the machine and shape the stock unti] you have split the line. If this is done properly you need not touch the work at all with a file. Remove the punch pad and stripper, tilt the ram of the machine 1% deg., and proceed to shape the die for clearance, The writer shapes through the die and shoe in this operation, since the opening in the shoe must be a trifle larger. Drill the hole in the die for the stop pin, as shown in Fig. 8. The die now is ready to be hardened. If the steel can be hardened in oil, and a gas furnace and pyrometer are available, there is little danger in the hardening process. If thesteel must be hardened in water, however, care must be exercised. Heat the steel slowly and, in the absence of a pyrometer, place a few pieces of the same steel in the furnace for use in testing. When you think you have the proper heat, quench one of these pieces and test with a file. In any case, see that all the holes in the die not to be used for cutting metal are plugged up with clay or asbestos. TOOL IN HEAD OF oOlE—, VERTICAL SHAPER yy —— LAYOUT TOOL PUNCH PAD © STRIPPER SHOE (PARALLEL O1iE ———= t —— SS H ©) SN omamts o a FTER-. the die is hardened, - it should be polished on Jé\cunros the top and the temper drawn ZAsouer to about straw color. This can be done in the furnace or on a hot plate. If an oil “teys tempering-tank is at hand, it 4a is only necessary to heat the oil to about 450° F. and leave the die in the oil until it attains this temperature. In this case no polishing is necessary. Grind the die on the top and bottom. The side of the die that is rounded should be ground last; otherwise rock- ing may cause difficulty. (Continued on page 140) The steps in making a typical punch and die in a shop that has complete and up- to-date equipment are illustrated in Figs 1 to 9. Figures 10 and 11 show the simplest method when a die must be filed by hand, the danger of spoiling the die being re- duced toa minimum through the use of guards that are sol- dered to the surface ANY time-saving shop ideas are contained in the continuation of the Bet- ter Shop Methods Depart- ment, which you will find on pages 135 to 145.

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n removed » die, and gain ag in ie table of ly line up h the ways stock until nis is done the work d stripper, , deg., and clearance, 1e die and he opening per. r the stop e die now in oil, and 2 available, hardening ardened in exercised. he absence ces of the ‘urnace for When you the proper e of these vith a file. hat all the tto be used ire plugged sbestos. ; hardened, polished on nper drawn olor. This he furnace . If an oil at hand, it to heat the '. and leave oil until mperature. polishing is on the top e side of the d should be rwise rock- ficulty. age 140) aving, shop ontained in of the Bet- ds Depart- u will find 45. POPULAR SCIENCE MONTHLY Are you interested in doing better work? If a beginner, do you want to know how to use your tools the way the best men in the shop use theirs? How to turn out work that’s right the first time? How to size up and go through with a difficult job with no lost motion? Get Vol. I of the Starrett Books. If you are a practical machinist, could- n’t you use to splendid advantage a book which puts at your finger tips im- portant formulas and technical dope— tables that relate to machine speeds, power transmission, drilling, gear cut- ting, turning and milling, materials, Handbooks, Vols. I, II and III etc.? Get Vol. II of the Starrett Books. If you work on cars and parts, wouldn’t you appreciate a clearly written, well illustrated book that covers the latest and most approved methods and gen- eral practice in automobile and engine repair work? Get Vol. III of the Star- rett Books. The famous Starrett Handbooks give you this information. Profusely illus- trated, approximately 200 pages of well printed text written for the man in the shop. And all for only 75 cents each. Send us that amount, if hardware dealer cannot supply you. Catalog No 23-‘‘W” sent free on request. THE L.S. STARRETT CO. World’s Greatest Toolmakers Manufacturers of Hacksaws Unexcelled Steel Tapes—Standard for Accuracy 8313 ATHOL, MASS. Is The Man That Gets Ahead IS) This seal on a radio or tool adverticement signifies the approval of the INSTITUTE OF STANDARDS, See page 6.

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from the Home as ~_ | OU will find scores of uses for hand clamps in your home workshop and for the hundreds of odd jobs that should be done around the house. With Jorgensen Adjustable Hand Screws in your tool chest, you will find scores of jobs that bothered you before can be held together in exactly the position you want with a few turns of the screws. The steel screws in the Jorgensen Clamps do away with the warping, swelling, sticking trouble and breakage of wooden screw clamps. The Jorgen- sen Clamps can be adjusted to any angle, thus doing away with the nui- sance of squaring up irregular surfaces which other clamps require. The spindles and sockets are made of fine quality steel and the jaws of sea- soned maple. The Jorgensen is a beau- tiful, useful tool. | | Take a tip from the Home Workshop De- ; partment of Popular Science Monthly and include hand screws in your tool equipment. It will give you more thumbs and fingers to work with—and you know how often you have wished you had a third hand when you have been gluing wood pieces, or doing other jobs that required the holding together of wood or metal pieces.

FITS ALL SHAPE JOBS As a user of tools you will rec- ognize the convenience of a hand screw that can be adjusted to whatever angle is required by the job you are doing. It comes in 12 sizes and can be used on hundreds of different jobs. Mail the coupon to-day for the Descriptive Circular—and, we suggest, order at Jeast one clamp to learn by first hand ex- perience the ease of doing jobs with Jorgensen Clamps. . Adjustable Clamp Co. Manufacturers of the

‘*+JORGENSEN’®’® STEEL SPINDLE HAND SCREWS . 212 N. Jefferson Street, Chicago Money Refunded if Unsatisfactory T ADJUSTABLE CLAMP CO., | 212 N. Jefferson St., Chicago | | Please send items checked below: | 0 Ship by mail, postage prepaid, ONE No. 5-0 gay Hand Screw (Length 4in., Jaw opening | 2 in.) for which I enclose $1.00 0 Ship by mail, postage prepaid, ONE No. O Jor- | gensen Hand Screw (Length 8 in., Jaw opening 4% in.) for which I enclose $1.50. | O Send latest descriptive bulletins. Money will be refunded if tools are unsatisfactory 8 and are returned within 30 days. |

POPULAR SCIENCE MONTHLY

October, 195 es Se

F itting Up an Attic Room Second Article in a Sertes on Reclaiming Waste Space in Your House—The Walls

LOORING laid, the Pees task in the building of an attic room is the raising of walls. Figure 4 gives the layout of the typical room described in these articles. The bottom plates, of 2 by 4 in. stock, sized to thickness and width, are tacked in place about the room, the end _ lengths running the full width of the floor joists and the others cutting in between.

made, it is well to check is considered, the room corners should be _ the joists.

scabs FALSE OR BACKING RAFTER e8 ; ae | Pe: JOIST 2 {i] HEADERS ~ 4 SS ==

That no mistakes are This model shows how the 2 by 4 in. wall studs are set up measurements by plumbing down to the fastened, straighten them to a stretched floor from the ridge, the width being line, by toe-nailing from the edges with measured from the center line. eightpenny common nails wherever there Since only the appearance of the inside isakink. Then spike through them into Avoid driving nails through made square, even though the floor joists the plate at the door openings as the may have been inaccurately placed. plate has to be removed from these open- When the ends of the plates have been ings before the door frames are placed.

2 rr Ns @ | - © ml = @ aS SS r | <——+ FALSE RAFTER © | CASING BLocks TT ’ ing | I We dy ne 1_ Bax Zz Z Z i a ve iE. H { HI 1 EE 4) i l 1 | i CLOSET A | A o o a “ Ld a0: ry | { = - a at PLAN OF 4 | . aaa STUDDING LAYOUT RAFTER BACKING i FOR ATTIC ROOM I

CEILING

E il 12H I

COPNER BACKING FOR PLASTER

———- eens eo i 5 Yl Nee WALL STUDDING \WHERE NO DORMER IS BUILT BACKING BLOCK Plan of a typical attic room, the studding at ends and sides, and details of the framing at corners and ceiling

The entrance-end parti- tion (Fig. 2) is laid out as follows: Measure from the corner 4 ft., locating the center of the fourth stud. Allowing 2 in. for thickness, lay off distances of 16 in. from edge to edge in both directions, placing a corner stud as shown in the corner detail (Figs. 8 and 9). If a pair of rafters hap- pens to be spaced so that, when plumb, the studding edges will bear against them, they may be used as sup- ports for the upper ends of the studs; but in all likeli- hood it will be necessary to “head across’”’ between raft- ers to carry the false rafters shown in Fig. 1. This is done by nailing a piece of 2 by 4 between the rafters above the ceiling and below the wall intersection, to which the ends of the false rafter can be spiked (Fig. 8). This rafter forms corner backing for the ceiling fiber or plaster wallboard. Instead of using two studs at the corners (Fig. 8), one stud with a backing of a 1 by 4 in. or 6 in. board nailed solidly behind it, as shown in Fig.9, may be used, but it is not as solid. The door space is trim- med 2 ft. 84 in. wide (allow- ing 2\4in.for plumbing and (Continued on page 126)

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ctober, 1935

are set up a stretched edges with rever there 1 them into ils through ngs as the these open- e placed. -end parti- laid out as re from the ocating the ourth stud. yr thickness, s Of 16 in. dge in both ng a corner n the corner nd 9). rafters hap- ced so that, he studding gainst them, ised as sup- oper ends of in all likeli- necessary to etween raft- false rafters 1. This is -a piece of 2 the rafters ig and below rsection, to of the false iked (Fig. 3). rms corner ceiling fiber oard. using two corners (Fig. th a backing or 6 in. board yehind it, as .9, may be not as solid. pace is trim- . wide (allow- lumbing and October, 1925

page 126)

after all..... “HOW WELL YOU CAN HEAR™= POPULAR SCIENCE MONTHLY is the only thing that really counts

OR a few weeks after we get a new radio set we all have the “logged 57 varieties of stations last night” feeling in our blood. Then we get tired and want to sit back and have some real entertainment. For, af- ter all, “How well you can hear” is the only thing that really counts—no matter whether the entertainment is coming from a localstationor one a thousand miles away.

Acme M A-2 Audio Frequency Transform- er—more amplification without distortion. “How well you can hear” IN THIS “how well you can hear” proposition is where quality comes in—and so does Acme. The Acme Apparatus Company, pioneer radio and transform- er engineers and manufactur- ers, have long made both transmitting and receiving apparatus of only the highest efficiency. Specialists in am- plification, even before the days of broadcasting, this company has perfected “am- plification without distor- tion.”

Make this test with your set DISTORTION does not mean merely squeals and Acme “Double Fre- edge Cone” Loud Speaker—for reproduc- tion without distortion. Oth edition of this famous book just off press ‘sy —send for your copy. A 40 PAGE book—over 200,000 of which have been sold at 10c a copy—gives the complete story of “Amplification without Distortion.” Use coupon. ACME

~for amplification © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

howls. Any thing which fails to give you an exact repro- duction of the human voice is distortion. Here is how you can test your own set. Start your radio and at the Same time keep up a conver- sation with two or three friends.

Unless you can understand the voice over the radio as easily as that of a friend sev- eral feet from you, and without any more concentra- tion and effort than is ordinarily required in talking with him, then you have distortion. The reason you have to concentrate when listening to a voice speaking over the ordinary radio (an action unnecese sary in ordinary conversation) is simply this: the individuality of the voice is lost because distortionjhas blurred out the over- tones which give this vitality and individuality. Monotones are always hard to understand. Acme B-eliminator for elimination without dise tortion. The whole story of distortion and how it can be over- come is carefully and fully explained in “Amplification without Distortion,” a book on radio reception which is invaluable because it is written by a famous radio engineer in language even the radio novice can completely under- stand. Over two hundred thousand radio enthusiasts can vouch for the service it will give you. Thousands have written us their thanks. The 9th edition is just off the press. Send for your copy. CLAUDE F. CAIRNS President, Acme Apparatus Co.

ee ee ew a a a

ACME APPARATUS CO., Dept. P2, Cambridge, Mass. Enclosed find 10c (coin) (stamps) to cover mailing of one copy of 40 page book, “Amplification without Distortion.” Name EOE i <, sinisciastactanrastnssascceiecettaabena diag tape aed Oi oad. ss cccacerdceinmsernensarnanbenconmenrencenaouiee State

Page 74

ie 1) gpa / y yy WN. ep W0. : ppl °C, YY “Vf yy fe i Wy ZA File your next saw with a YEP. Yi YH) ZZ POPULAR SCIENCE MONTAL/ October, 1925 = How to Use a Coping-Saw Marking and Cutting Fretwork By Emanuel E. Ericson, Noted Manual-Training Authority And you will then know b speed of filing. Plumb Files are of special taper, perfect- ly cut with keen edges Za oth ease and ty YY Ly Uy Lidaitidd: Lie Vd Yj le 1 A coping-saw is used for cutting toy parts from thin wood, for making fretwork and overlays for furniture, for fitting moldings to- gether, and for many similar purposes. The simplest type of coping-saw is shown above. The blade is inserted so that the teeth cut when the saw is pulled downward 2 To transfer a pattern on the wood or other material, place a sheet of carbon paper face down between the drawing and the stock, and fasten with thumb-tacks or nails, so that there will be no danger of the pattern’s shift- ing. Trace the outline very carefully with a sharp, hard pencil or any pointed instrument ee ee SATE MER EE RED 28> that stand up. The edge of a Saw File is the life of the File. Three Files do all your work: The 514" for fine \\ Saws 10 to 12 point - where a short stroke is all you can use. The 7" is designed for a long sweeping stroke. Use this on your 6 to 10 pt. Saws. The 8" is for your largest Saws. Use with a rigid stroke. Plumb design, steel, cutting and temper solve your filing troubles. Try your hardware dealer. If he does not have them send,75c (stamps will do) and we will mail you all three Files at once. FayetteR. Plumb, Inc. 4818 James St., Philadelphia 514 in. © 4 in Oc 5 ty tt} Vda Yypyyy7:; ty I PLUMB DOUBLE LIFE AMATI Hammers Hatchets Files Sledges Axes 4 Below: Lay the wood on the “saddle,” grasp the saw handle firmly, and saw on 3 The simplest type of sawing-table or ‘“‘saddle”’ is a board with a V cut, which is clamped to the edge of a bench or table. the down stroke. Turn the saw or the wood, or both, so as to fol- low the outline, and cut on the waste side of the line. When necessary, the blade may be set at right angles to the handle 5 When an inside cut is to be made, a hole is drilled so that the blade can be inserted in it before being fastened in the frame. For cutting fretwork of large area, use a bracket saw frame, as it is much deeper from blade to back - 6 Moldings are ‘“‘coped’”’ to join each other at a right angle by cutting a miter at the end of one piece and sawing through the line where the miter and the face of the molding intersect. The abutting molding is not cut at all © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. im wes” te (se. ee - ae Cee

Page 75

er, 1925

or other m paper 1e stock, , so that 1’s_shift- y witha strument ‘saddle,” l saw on he wood, as to fol- line, and raste side When he blade at right e handle join each cutting a yiece and the miter intersect. cut at all

October, 1925 POPULAR SCIENCE MONTHLY 79

ti cS @ ‘Foes. os : 2 Seam. ) &, J | Whether you smile or cuss depends upon the service behind your Radio~ The handy man who can fix any radio simply experiments until he locates the trouble—such a method / . was disastrous to the auto in former Do you ever have little things go days—it is disastrous and expensive wrong with it? in radio today. It is not sound. E) EUFREN

fi — (‘ean € —e, HAT is this radio service which we claim is so necessary? Openings for a Few More OZARKA Factory e i ° Ko = have become so used to minor Ozarka instruments are sold only by Repres entatives troubles that you don’t condemn the : DET Ch, tise eecnstenalie ecour Ozarka factory representatives, men ZARKA Incorporated, is now entering y y * who are factory trained in sales and O its 4th year. From a:negeanes aae - service, men who sell no other radios engineer, one stenographer, one sales- = ; ast: Chanel man-our present president, theOzarka organ- You go right to a service man—a_ but Ozarka. ization has grown to over 3,100 people. There man who knows your make of car. 3 must be some good reason for this growth. ‘ These men don’t pretend to know Ozarka instruments heve made good—they have ou dont go to a handy man who claims he can fix any car. all about radio but they do know al] more than met competition. Ozarka representa- ° ees tives have made good not only because Ozar there is to know about Ozarka—isn’t instruments were right, but because they have ; : : : ; : b That's automobile service, and is one that thekindof radioservice you want? Pogn willing to learn Reig eg ee sm of the main reasons for the auto being usual salesmanship and Ozarka service. s the success it is today. Ozarka instruments are sold under _,, There are still openings for the right men in thie : oe . ~ a very definite plan An Ozarka repre- bs [essed dhxaneoue of waskdnated mew ty es ‘The same service condition exists in east ill lad] 3 t O k else—men who want a business of their own. Prove radio—the only difference being that sentative will gladly set up an UZzarka = yourself by sales and willingness to learn and people don’t yet understand it. Do you drive a car? No— in your home—he won't tune it—he cxclusive territory will be given you. The man we want has lived in his community for some time. He won't tell you what it will do—you has the respect of his fellow men because he has The radio instrument which never must operate yourself, If the results never “‘put anything over’ Boe to make money. He may not have much money, but he is not broke and requires service has never been built you receive by your own operating is, at least, able to purchase one demonstrating —it never will be. won't convince you that the Ozarka re Like automobile manufacturers, the g!Ves you the distance, volume, selec- Send for FREE Book better radio manufacturers do all tvity, tone and ease of tuning that within their power to make their in- Y°U demand then don’t buy it. struments mechanically perfect. Nev- ertheless, like the auto, little things will sometimes go wrong—they are serious to the radio owner but very simple toa factory trained service man. Radio offers a wonderful opportunity to men who are willing to start at the bottom and build. You need not know salesmanship, but will you learn . £ what we will gladly teach you? You may not know Ozarka instruments are built to sell radio, but we can and will teach you if you will do . . your part. With such knowledge and willingness to themselves but no Ozarka is sold with- work, it doesn’t seem possible that you cannot make = : : : good. Sign the coupon below, don’t fail to give the out fastory trained service behind it, name of your county. Better still write a letter, tell us about yourself and attach the coupon. If interested in our salesman’s plan ask for ““Ozarka Plan No. 100.” (NCorpoRATED 120 Austin Avenue R Chicago, Illinois

120 Austin Avenue R Chicago, Illinois

———

Gentlemen: Without obligation send book “‘Ozarka Instru- ments No. 200” and name of Ozarka representative.

Gentlemen: I am greatly interested in the FREE book “The Ozarka Plan” whereby I can sell your radio instruments,

SESE SOE ee ee or WOMB. ......0ccccccccsecerecccsseoszascennooesedha madi Nhe a oe a ae MEM cose Sosa hoces xe You'll Know the Man Address ..........- Sededhstethcaseameae CY, Sacscctanascene dei ae aed ae a Behind This Button! CORNER i Fos ares euiaelecenmenant States. .5.<0.seee0rs © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

Page 76

Westinghouse Rectigon Battery harger The Rectigon re- charges BOTH 66 A and “B” bat- teries easily and quickly. There’s no muss or fuss; no acids or chemicals to bother with— No moving parts, and no noise. © No storage- battery radio is complete without a Rectigon! POPULAR SCIENCE MONTHLY October, 1935 WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY South Bend, Indiana WESTINGHOUSE ELECTRIC Me WORN Workshop] How to Perform the Mystifying Thimble-Handkerchief Trick By Kenneth B. Murray kerchief is a neat, simple, and _ in- expensive little illusion that can be mastered quickly by any one interested in parlor magic. It never fails to astonish those who are not in the secret. You show your audience an unprepared thimble and a small black handkerchief. Then you place the thimble on a finger of the left hand and cover it with the hand- kerchief. The next instant you appear to push and pull the thimble violently half- way through the handkerchief. After the audience has been duly impressed, you Prrecrerier a thimble through a hand- Purchase two thimbles and paint the lower part of one of them halfway around, using any good non-gloss, moisture- proof paint, black in color Place right hand over form of first thimble, which shows through the hand- kerchief, and push Show the unprepared thimble and a small black handkerchief to the audience. the thimble on the forefinger of your left hand and cover it with the handkerchief. prepared thimble concealed in the right hand pull it all the way through, immediately giving the undamaged handkerchief anq the thimble to the spectators for ex. amination. How the trick is done is shown in the photographs below. Practise this ily. sion 15 times and you will be able to foo] almost any one. The method is entirely different from that commonly used, which requires a thimble previously cut in two, and has the advantage that the hand pulling the thimble through the handker- chief can be shown entirely empty, ag there is no half-thimble to be concealed, Then place Have the Give spectators the prepared thim- ble on it. At a short distanceit will seem asif the thim- ble is sticking half- way through the handkerchief At the right: “‘“How to palm or conceal a thimble.” It is held lightly at the root of the thumb time to appreciate the feat and then pretend to pull the thimble entirely through the hand- kerchief by giving the prepared thim- ble a half turn so that painted part is at the back, as you remove it. Finally offer the plain thimble and_ the handkerchief for examination NEXT in Mr. Murray’s series of par- lor magic classics is an article on how to make a new type of handker- chief-vanishing apparatus. If you wish any special trick explained, the Editor will be glad to hear from you. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6,

Page 77

October, 1935 ring ck mediately rchief and Ss for ex. wn in the this illu- ble to fool is entirely sed, which ut in two, the hand 2 handker- empty, as concealed, a small nen place left hand Tave the ght hand pectators appreciate and then to pull the entirely the hand- by giving ared thim- lf turn so ited part is ack, as you t. Finally he plain and_ the rchief for ination If you wish the Editor le October, 1925 POPULAR SCIENCE MONTHLY Perfected with RCA Tube HE Super-Ducon replaces the “B”’ Battery, operates from the light socket (110 to 115 volts, 60 cycle A.C.) and is absolutely noiseless when properly installed. Every radio man knows the results he gets when his “B” battery is at its best. The Super-Ducon gives him this top- notch volume ail the time. As now furnished, the Super-Ducon has a specially designed RCA _ tube—Rectron U.V. 196, which has an average life of more than 1,000 hours. Tested and listed by the National Board of Fire Underwriters Write for descriptive bulletin. Address: 4377 Bronx Blvd., New York City. Dubilier CONDENSER AND RADIO CORPORATION © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. | Price %4,7-50 ecially designed

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99 A Necessary “Tool For Your Workshop OR the man or boy who has a home F workshop, Lee Union-Alls are a handy “tool” to have about. All that is necessary when you want to get busy is to slip into them and start your work. They cover the body from head to foot and can be worn over other clothing. They save clothes, also. And they save time where the hours for such work are limited. Wear Lee Union-Alls, the original one- piece work suit, worn by thousands of mechanics, shopmen, garage workers and industrial workers. Lee Union-Alls are quality-built—close-woven cotton fab- ric, riveted rustproof buttons, reinforced strain points—fully guaranteed to give satisfaction. They give solid comfort, long wear, and are neat in appearance. Accept no substitute—look for Lee onthe buttons. Thousands of live dealers sell Lee Union-Alls: Ask your dealer today! THE H. D. LEE MERCANTILE Co. Kansas City, Mo. Trenton, N. J. South Bend, Ind. Minneapolis, Minn. San Francisco, Cal | it i \ nad \ i Lee Overalls and Work Shirts are * other items in the famous Lee line. They are quality-built, also. POPULAR SCIENCE MONTHLY October, 1925 lone We HREE cigar boxes and a little spare time is the recipe for the ornamental box illustrated helow. It can be used for holding cigars or cigarettes, trinkets and odds and ends or, if lined with plush, as a jewel casket. There are, indeed, so many uses for it that you can be sure you will find it serviceable and, of course, it will make a most acceptable Christmas present. It is much easier to make than the photograph might suggest at first glance. The basis is a cigar box. Whether you will need to take the original box apart, scrape the paper off, sandpaper it and re- assemble the pieces will depend upon what kind of a cigar box you have obtained and whether or not you intend to line the interior. The ornamentation is built up in layers, each one cut % in. smaller in size than the one below it. For example, if the original cover of the box is 6 by 8 in., the next section will be 51% by 71 in., the next, 5 by 7 in., and so on, until you have obtained the thickness you desire. With a ruler divide each edge of each section with lines % in. apart. Then | between each of the marks cut a V- | shaped notch with your pocket-knife. These notches should extend in from the | edge 4 in. so as to bring the points of the | notches to a line where they will meet the LeeUnion Alls edge of the section above. Your initials carved on the top section will look well, or the initials of the one st An ordinary cigar box decorated with the simplest variety of pocket-knife carving | to whom you intend to give the box, if it is to be a present. Mark them care- fully and cut away the surface so as to give a raised effect to the letters. There is no special rule to go by; in fact, one of | the fascinating things about whittling is that you can do everything to suit your own taste. : As a rule, carving should not be sand- papered, as it is desirable to have the tool | marks show to some extent; but if you | have left any rough places, it will be well, Simple Cigar-Box tling Pocket-Knife Is Only Tool Needed to Carve Attractive Patterns in Thin Wood By Herbert I. Childs perhaps, for you to touch them up with fine sandpaper. The sections are glued in place either with hot cabinet glue or a good grade of liquid glue, and a few fine brads can be used where they will not show, if care is taken not to split the wood. Work of this kind does not require a highly polished, glossy finish. You may stain the wood, if it is not dark enough to suit your fancy, and either give it one or two coats of very thin shellac, or one coat of thin shellac and one coat of flat drying varnish or furniture wax, or merely a coat of genuine linseed oil and turpentine mixed half and half and applied warm. There are five important points to ob- serve in all whittling. Close your hand about your knife with the thumb over the fingers, as if to reinforce them—a good firm grip and yet not so tight as to cramp your hand. Always cut with the full length of the blade, if possible, drawing it from the heel to the point. Do not let your knife get dull. As soon as it begins to draw hard, sharpen it by the method described in my article last month. Always whittle away from you, if you can; you will cut faster, as well as insure yourself against accident. Do not use your knife as. a screwdriver, a can- opener, or a hammer; countless good knives are spoiled through such misuse. Put a drop of oil now and then on the spring end with the blades three-quarters closed. Dry joints are harmful to the knife in time and in many cases are @ source of annoyance to the user because the blades will not. close entirely. "Two especially noteworthy articles for amateur mechanics are on the schedule for next month. One tells in detail how to use glue to the best ad- vantage in the home workshop. The other is on fitting and hanging storm sash quickly and accurately. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

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ober, 1925

1 up with ace either 1 grade of ds can be if care is require a You may enough to 2 it one or yr one coat flat drying merely a turpentine d warm. ints to ob- your hand ib over the nm—a good is to cramp h the full drawing it Do not let as it begins she method st month. rou, if you 11 as insure Yo not use er, a can- ntless good uch misuse. then on the ree-quarters nful to the cases are @ iser because rely.

hy articles are on the One tells in he best ad- cshop. The ising storm

October, 1925 POPULAR SCIENCE MONTHLY 83 This Year — Better, But Crowding Still Troublesome

Last Year— Bad Crowding of Shorter-Wave Stations Next Year— No Crowding! Straight-Line-Frequency Means— That the distance on your dials from one station to the next adjacent one isuniform—throughout the short-wave KYW, KSD * 535 °545 10 Meters

tions, as well as the longer waves. a nie . KGO, WDAF _| 361 36547 AT : \ \ 360 BEGREE | | WENR, WEAH, || ” ak / © 266 %268 < att A AA UNING / / 2Meters ee a ' sana ed Pa ws 2 “a At 4 e J 4 WEBH, WABW ZO | jackerP [Le 205% *°207 |= ’ | Sad arm) —— S e**loe 7 vc 12 Meters Aa sweet Ae Zp" es x = Pt nt Later’ Ret | oT Le bgney : ee Tt 20-KILOCYCLE INTERVALS ARE SHOWN:

ALTERNATE CHANNELS OMITTED FOR CLEARNESS ALL-AMERICAN STRAIGHT-LINE-FREQUENCY ‘TUNING All-American Straight-Line- Frequency Condensers Type C-35 Max. 350 micromicro- WAVE CHANNELS As ASSIGNED U.S.STATIONS (BY FREQUENCY)

All-American Toroid Coils Type T-1 Antenna Coupler $3.50

ete tin. = rumf.) oe ee- $4.50 Type T-2 R.F. Transformer 3.50 Toke (Min. 11.8 why —" 5.00 Set of 3 Coils complete .. 10.50

Ease and certainty in tuning —no more crowding of short- wave stations—no need to buy vernier dials — no gears or other back-lash makers—body capacity absolutely not distinguishable — electrical efficiency unsurpassed — on one-half the panel space: that is the Att-AmERICAN Straight-Line-Frequency Condensers. New power for distance reception through close coupling —tuning of arrow-like sharpness—elimination of all oscil- lation worries through the self-enclosed endless magnetic field — non-radiating reception: that is Att-AMERICAN Toroid Coils — Antenna Coupler and Radio Frequency Transformers. See them at your dealer's. A new edition of the famous RADIO KEY BOOK, together with complete information about the new ALL-AMERICAN Straight-Line-Frequency TUNING, is yours for 10 cents, coin or stamps. Send for it today sure! ALL-A MERICANRADIO CORPORATION, E. N. Rauland, President, 4215 Belmont Ave., CHICAGO OWNING AND OPERATING STATION WENR—266 METERS AtL-AMERICAN Pioneers in the Radio Industry © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

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84 Five Ratchet Adjustments 1. Plain Drill 2. Left-hand Ratchet 3. Right-hand Ratchet UBLE Ratchet 5. Gears Locked Drilling fender to install stop-signal, or parking light, one of the many jobs for which this handy little tool can be used. Dwarf zn size Giant zm service “Vankee’” Hand Drill No. 1530 is the biggest, little tool you can own. Only 101% in. long. You can carry it in your pocket. Weighs but 1/4 pounds. Yet it has all the famous ratchet adjust- ments of the big “‘Yankee’’ Hand Drills and Breast Drills. “YANKEE” Ratchet Hand Drill No. 1530 Works in places impossible for other drills, by means of five ratchet adjustments, controlled by just a finger touch on the ratchet shifter. 3-jaw chuck holds round drills up to 3/16 in. Some other ‘‘Yankee’’ Tools Ratchet Bit Brace Ratchet Screw-drivers Ratchet Bench Drills Ratchet Chain Drills Dealers everywhere sell ‘‘Yankee’’ Tools *“*Yankee’’ on the tool you buy means the ut- most in quality, efficiency and durability Write for FREE ‘“‘Yankee”’ Tool Book Nortu Bros. Mre. Co., Philadelphia, U.S. A. “YANKEE” TOOLS Make Betlv Mechacdicy POPULAR SCIENCE MONTHLY October, 1925 Striking-Bag Mounted to Give Realistic Boxing Practice HILE it is unlike any- \ V thing that can be found in sporting-goods stores, the method of mounting a striking-bag shown in the ac- companying illustrations has ad- vantages that immediately will be apparent to every athlete. The ball rebounds at various angles from the slanting rafters and boards, so the boxer is af- forded an opportunity to block, duck, side-step, and back-step, approximating actual boxing movements, instead of going through the usual monotonous drumming exercises. The idea had its origin in im- provising a striking-bag mount- ing in an attic, as in Fig. 1. The only materials needed for such a mounting are six boards. They are placed between the rafters to prevent the bag’s being penetrated by any shingle nails that stick through the roof. The sharp corners of the three rafters against which the bag caroms are rounded to a radius of 1 in. with a plane. With rafters pitched at the usual angle there will be about 28 in. of rope between the loop in the bag and the swivel, if the bag is hung at about the height of the stomach, which is to be recommended. An elaboration of the same idea, de- signed for a large training or recreation camp, is shown in Fig. 2. It is a four- bag platform. One bag is mounted in the CROSS PIECE SUBSTITUTES BRACES, / f Heavy / SAND BAG Pig. 1. in an attic. Fig. 2. Outdoor stand for four bags Fig. 3. Simple mounting for one oe Novel method of mounting a striking-bag Only six short boards are required usual style under a horizontal platform. A heavy. sand bag is suspended from one end of the cross piece and a “double- ender” is provided at the other end, The fourth bag is mounted as previously described. Guy wires provided with turnbuckles can be substituted for the upright braces A and B and if a light “‘exhibition” bag is used under the platform, the triangular braces indicated at C-D will be sufficient, | Figure 3 shows an outdoor or straight wall platform for a single bag. In case a heavy “oym”’ bag is. used, the back and ends should be boarded up to form a V- shaped trough, which should be filled with sand. The top should be covered with a sloping roof to keep thesand dry. The “two by four” from which the bag is suspended can be braced, if neces sary, with triangu- lar blocks screwed in place.—R. L. K. 4's" UPRIGHTS Mixing | Paint and Whiting to Make Putty N PAINTING about the house, small amounts of putty are required at intervals, yet if prepared putty is pur- chased in pound cans, it becomes hard and . unusable in time. I find it is better to mix a little dry whiting with a bit of the paint that is being used. This can be done in a moment’s time and the putty then matches the paint in color. There is no waste, as only a sufficient amount for the job on hand need be mixed. This method is especially desirable when flat-drying interior paints and enamel undercoaters are being used, be cause ordinary linseed-oil putty should not be used with them.—R. E. CHAFEE. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6

Page 81

tober, 1925 iking-bag required 1 platform. .d from one a ‘‘double- other end. ; previously turnbuckles right braces tion” bag is 2 triangular ye sufficient, or straight latform for le bag. In a heavy bag is used, ek and ends be boarded form a V- d trough, should be with sand. p should be ed with a ‘roof to keep id dry. The y four’’ from the bag is ded can be if neces- yith triangu- cks screwed e.—R. L. K. utty olor. There ient amount mixed. ly desirable paints and ng used, be utty should E. CHAFEE. October, 1925 (fae Home Workshop | Blueprints Will Aid You in Making Christmas Presents HAT are you planning to make in the way of furniture for Christmas presents? If you have in mind anything elaborate, the sooner you get your ma- terials together, the better. You ia need first of all a trustworthy and carefully de- tailed working drawing and a complete bill of materials or cut- ting list, as wood- workers often call it. Just here the Home Workshop Department can be of real assistance to you, for it offers you a wide range of blue- prints—listed below—at the nominal price of 25 cents each. Especially to be recommended for Christmas gifts are the sewing table (No. 1), the smoking cabinet (No. 2), the kitchen cabinet (No. 5), the tea wagon (No. 18), the workbench (No. 15), the cedar and mahogany chest (No. sini and the radio sets (Nos. 41-43). Bench (15) and Smoking Stand (2) Complete List of Blueprints a one of the blueprints listed below can be obtained from POPULAR SCIENCE MONTHLY for 25 cents. The Editor will be glad to answer any specific questions rela- tive to tools, material, or equipment. Blueprint Service Dept. Popular Science Monthly 250 Fourth Avenue, New York GENTLEMEN: Send me the blueprint, or blue- prints, I have underlined below, for which I inclose.............. cents: No. Title Published Price 1. Sewing Table Feb., ’22 25c 2. Smoking Cabinet Mar., ’22 25c 3. End Table Aoe., “a2 25c¢ 5. Kitchen Cabinet May, ’22 25c 8. Shaving Cabinet June, ’22 25c 9. Arbor, Gate andSeats July, ’22 25c 10. Porch Swing Aug., ’22 25c 11. Bench and Tilt Table — ‘an +25c 12. Electric Washer "2a 06s se 13. Tea W agon — "22 25c 14. Christmas Toys Dec., °22 25c¢ 15. Workshop Bench Jan., ’23 25c 16. Inlaid Radio Cabinet Feb., ’23. 25c 17. Cedar Chest Mar., ’23 25c 18. Phone Table and Stool Mar., ’23 25c 19. Grandfather’s Clock ie: 2s Zac 20. Flat-Top Desk Apr., “23 25c¢ 21. Colonial Desk Apr., ’23. 25c 22. Cabinet and Desk Ase., "23 25¢ 23. Pergola Garage May, ’23 25c 24. Gateleg Table June, ’23. 9 25c 25. Canoe Sailing Outfit July, ’23 25c 26. Baby’s Crib and Pen Sept., ’23 25c 27. Kitchen-Cabinet Table Oct., ’23 25c 28. Pullman Play Table Nov., 23. 25c 29. Toy Tea Cart, etc. Dec., ’23 25c 30. Tool Cabinet, etc. Jan., ’°24 25c 31. Sewing Cabinets Feb., ’°24 25c 32. Chinese Game Table Mar., ’24 25c 33. Dining Alcove Apr., ’24 25c 34. Garden Trellises May, ’24 25c 35. Simple Radio Cabinet Oct., °24 25c 36. Rush-Bottom Chair Nov., ’24 25c 37. Simplified Bookcase Dec., ’24 25c 38. Sheraton Table Jen., "25 25¢ 39. Salem Chest Feb., 725 25c 40. Desk in Sheraton Style Mar.,’25 25c 41. One-Tube Radio Set May, ’25 25¢ 42. Three-Stage Amplifier June, ’25 25c 43. Four-Tube Receiver july, °25 25c 2979 POPULAR SCIENCE MONTHLY We Want Men with tough, wiry beards to challenge this Let us send you free a 10-day tube of this unique shaving cream which softens the toughest beard in one minute! EN claim that Palmolive Shaving Cream will soften the toughest beard in one minute. No finger rubbing—hot water or ‘cold, hard water or soft. That’s a broad statement, we’ll agree. You may doubt it. But, if true, you want that kind of shaving. Let us give you a 10-day tube free. Find out for yourself. We believe we'll win you, no matter how firmly you are wedded to a rival preparation. NEW Principles Palmolive Shaving Cream is a new-comer in its field . . . yet, to- day the leader. Millions of men have quit old ways and adopted this new shaving oy. Probably 80% of its users were boosters for other makes of cream. All were won over by the test we now offer you. “Don’t buy—yet,” we urge you. Put the proof burden on us. * * * 60 years of soap study stand be- hind this creation . . . made by the makers of Palmolive Soap. PALMOLIVE lll 10 SHAVES FRE 130 formulas were discarded be- fore we found the right one. 1000 men told us their supreme desires in a shaving cream. Only by great effort did we meet them. New principles were required. New laboratory methods and ex- periments. Palmolive Shaving Cream thus is different from any other you have known. 5 New Delights These you’ll find—these- new shaving joys, these comforts un- known before. 1 Multiplies itself in lather 250 times. 2 Softens the beard in one minute. 3 Maintains its creamy fullness for 10 minutes on the face. 4 Strong. bubbles hold the hairs erect for cutting.., 5 Fine after-effects, due to palm and olive oil content. 10 Shaves Free Now in fairness to us, and in justice to yourself, clip the coupon before you forget. Find out whether the whole world is wise in changing to a new way in beard softening. and acan of Palmolive After Shaving Talc Simply insert your name and address and mail to Dept. B-1072, The Palmolive Company (Del. Corp.), 3702 Iron Street, Chicago, III. Residents of Wisconsin should address the Palmolive Company (Wis. Corp.), Milwaukee, Wis. @ This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

Page 82

POPULAR SCIENCE MONTHLY

HP Yae RRR AR LAE he feet

“Yes, Jim, that’s why I gota better job’’ “In the first place, remember, I have a kit of good tools. While the rest of you boys were shooting pool or at the movies, I was studying and building up my kit with Brown & Sharpe Tools getting ready for a bigger job. Some. of the tools I didn’t really need then, but I was certainly glad. I had them later. When my chance came, I was ready,—that’s why I got a better job.”’ Every mechanic finds that only with the best tools can he do his best work. With a good kit he is qualified to go higher. —He is equipped for the bigger job when it comes. Build up your kit with Brown & Sharpe Tools. Send for Small Tool Catalog No. 29 BROWN & SHARPE MFG. CO. Providence, R. I., U. S. A.

BROWN € GHARPE TOOLS © ‘‘Standard of the Mechanical World’’

Oc tober, 193

———____ dite Tome Worlksiae How fo Reline Auto Clutches By Ray F. Kuns Principal, Automotive Trades Schoo] Cincinnati, Ohio VEN with the best of care, clutches will wear out and need new linings or facings. A well designed clutch, cared for as suggested last month, wil] give- many seasons of average service without relining. In many instances the clutch facings will not need to be replaceq in the life of the car. In other cases the clutch facings will be damaged, seriously worn, or cut out. The average car, excepting the Ford, has a so-called unit power-plant mount- ing of the clutch and transmission on the flywheel housing of the engine. The transmission case has a bell housing cast or bolted on it. This housing is machined to fit and be bolted to-the flywheel housing. Con- . : i sequently it is necessary to re- move or ‘“‘drop’’ the

=~ SS ———— = LSS = <——s

: Wi , F ml gph 7 x TANS IA eh OS ee) e Si wi AE NM, - * 28 Applying Clutch Facings The rivet head is rested on a punch held in the vise, and a common rivet set ora ball-peen hammer is used to form the burr transmission whenever repair work is to be undertaken on the clutch. Individual cars may vary in this re spect, however, and there are a number of cars having what is known as an amidship transmission mounting. As in the case of the unit power plant, it will be necessary to release and remove the transmission for any clutch work. When preparing for the removal of the transmission, first place the car where it will be most convenient. Block the front wheels to -prevent it rolling, since the brakes must be disconnected. Remove all brake connections, speedometer con- nections, and other attachments. There is always a universal attached to the rear of the transmission and from this uni- versal a propeller shaft is run to the rear axle, where there may or may not be another universal, depending on whether or not the propeller shaft is of the type inclosed in a torque tube. If the torque-tube construction is used, there is only one universal, and in order to drop the transmission it first is neces- (Continued on page 90)

@ This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

Page 83

des School, are, clutches new linings gned cluteh, month, will rage service nstances the » be replaced er Cases the ed, seriously g the Ford, lant mount- ission on the gine. The housing cast ‘is machined che flywheel ‘ings nch held in t set ora m the burr r work is to - in this re re a number 10Wn as an ting. As in slant, it will remove the york. noval of the car where it ck the front r, since the d. Remove ometer con- nts. There 1 to the rear m this uni- 1 to the rear may not be on whether of the type tion is used, ind in order rst is neces- ) 6. ee October, 1925 POPULAR SCIENCE MONTHLY 89 ~ Kolster’s Genius F. A. KOLSTER For eight years he was head of the Radio Section of the United States Bureau of Standards. He invented the Kolster Radio Com- pass for Navy and passenger ships. The staff which he heads built most of the United States Navy Radio Stations. ! | ! | LL TT TT ee Te TT Kolsters are presented in four mcdels, one of which is pictured here; two are cabinets, two are for tables. O V1alS. Super-tone is only one of many Kolster advancements. This remarkable instrument has no dials! Here is ultimate simplicity you've been expecting. You just turn from one station to another on a register bearing the names of the different stations. No “tricky” tuning with numerous dials. A child can operate it—perfectly every time. _ AKolster is to today’s radio what today’s automobile is to the old “‘horseless”’ carriage. It is extremely powerful—selective and sensitive. All the old-time handicaps are eliminated. No “background” inter- ference, no “howls.” Brings a New Thrill in Radio— It was bound tocome! Thisnewera in radio. Some great pioneer staff of radio experts was destined to introduce that most wanted feature in radio: Perfected repro- duction. That honor has fallen to Kolster and his associates. Now comes a distinct new era in radio —the experimental period of reception is over. Now reproduction is the new-day development. To hear a Kolster is a revelation of radio's real possibilities. Never have you heard such reproduc- tion—so startlingly real, so free from in- terference. New magic! _ And all because of certain Kolster re- finements. This great genius has found the way to reproduce a broader range of tones. In all their charm, the subtle overtones —the hitherto “lost chords” are now developed. Now radio becomes genuinely realistic —not merely mechanical transmission of sound. A Surprise, Indeed Hear this wonder instru- ment—either at the nearest Kolster dealer or in your own home. Kolsters are housed in fine cabinets—master- pieces of design and beauty, adding charm and elegance to any room. Once you hear the Kolster, you ll revise your standards of radio enjoy- ment—you'll be unhappy with a lesser instrument. Discriminating people are saying with justifiable pride: “I own a Kolster. KOLSTER RADIO © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

Page 84

POPULAR SCIENCE MONTHLY SPECIAL SAWS “of SPECIAL STEEL HERE is a Simonds Service Shop or Supply Dealer near you to furnish promptly Simonds qualityCircular Saws, Band Saws, Files, and Planer Knives. | Write for Mill Saw 5 Catalog. SIMONDS Pronounced Si-MONDS SAWS FILES KNIVES STEEL SIMONDS SAW AND STEEL COMPANY, Fitchburg, Massachusetts “The Saw Makers” Branch Stores and Service Shops in Principal Cities Established 1832 October, 1995 c | dae rlome Workehom| How to Reline Auto Clutches (Continued from page 88) sary to loosen all brake rods and then the spring clips holding the springs to the rear axle. When all the items that might prevent the removal of the rear axle are loose, the car frame is jacked up high enough to take all the weight off the rear springs and blocked securely in that position. Next, roll the rear axle back far enough to allow the splined joint of the universal to separate. Covering the universal in this type of construction is a boot of leather or a steel] cover of ball-and-socket type. This will have to be loosened. In other instances the front end of the propeller shaft is carried in a yoke and in that case the yoke pins need to be removed. When the construction involves the use of an exposed propeller shaft there are always two universals. In this construe- tion the rear axle need not be moved back, but the universals are removed from their flanges by removing the bolts, Before the clutch can be taken out, the transmission must be removed from the car and thus the propeller shaft and uni- versals are removed together. Whatever the construction, the transmission cannot be dropped until the propeller shaft is removed. After the attachments to the trans- mission are all free, the bell-housing type of transmission is removed by taking out all the small capscrews or bolts used to clamp it to the flywheel housing. Block up under it to prevent its dropping down when the screws are released. If there is a clamp supporting the clutch and brake pedal, it should be loosened. When all parts are loose, slide the transmission back on its blocking. Note the small ballbearing on the forward end of the clutch shaft or in the flywheel center, which is used to carry the forward end of the clutch shaft and keep it in alinement. This is an important point in reassembling. Slide the transmission out from under the car and remove the clutch and brake pedals and throw-out mechanism. This will allow the clutch to be removed as a unit in most cases. Place the clutch under a press or use several blocks and a jack to compress the clutch springs. As a rule, a split washer will be found that may be removed and thea the clutch springs released and the plates sepa- rated. Note carefully the method of clutch (Continued on page 92) ; © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

Page 85

POPULAR SCIENCE MONTHLY tcheg aad : Fy ECONOMY rings to et ems that 2 EVEREADY HOUR Ene No ONE size or type of battery can be the rear ae =KVERY TUESDAY AT 9 P, M. is jacked Eastern Standard Time oe economical on every type of receiving . é F 1 radio enjoyment, tune in th i ‘ a upyeready Group.” Broadcast through : set. That’s.why Eveready Radio Bate securely stations— rear axle New York r : teries are made in different sizes and rovidence WSAI Cincinnati _ splined w ——_ (Bingerraus ae types—so that every radio user can 3 ullalo . Pau tits ° e s type of Pittsburgh WOC Davenport enjoy the economy that is to be had by This ai a : | fitting exactly the right Eveready Bat- instante ee tery to his receiver. Even owners of shaft is : : sets with five, six, eight or more tubes, case the ° ° and power amplifiers, can realize Ever- s the use eady economy to the full by using the onstelll ) dically different Eveready L onstrue- 8 new, radically different Eveready Layer . a | bilt “B” Battery No. 486. There is an he bolts : : fveready dealer nearby. Manufactured and guaranteed by NATIONAL CARBON COMPANY, Ine. New York San Francisco Canadian National Carbon Co., Limited, Toronto, Ontario EVEREADY —- Radio Batteries a oe ee ~they last longer and uni- ree hatever png n cannot GENERAL PURPOSES shaft is INSPECTED! RELIABLE _ ne. le trans- i i SND" Oe -housing apie oved by rape 0. rows Eveready Qian 22%4-volt flywheel Columbia prevent igen rews are ar he pporting the hould be SS a MADE IM U.SA- lide the zy. Note ard end flywheel forward ep it in nt point 1% volts Layerbilt Bee ier Pearse He SESH Extra- m under 2 | ‘a . fe pen eee eeeet Large d brake EEE s 20 s ae Vertical This ie aie ee eer aaa $5.50 ved asa i Suiits HIE PSE SaeetSeteStegE S or use press the asher will lthea the ites sepa- of clutch tS] This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS, See page 6.

Page 86

Here’s the Brace, men that you have dreamed of PEN up the jaws of that powerful chuck and feed it the biggest, fattest square shank you can find. Try an expansion bit if you have one. See how it slips through without a murmur. Put your hand around that finely knurled hardened steel chuck shell and run it down. How those jaws do grip! Drop in a Morse Taper shank or a straight round shank, same result; perfect centering and that bulldog grip. Put the hexagon nose of the shell in a wrench or vise if you want a still more posi- tive grip; you cannot hurt this little brute. That goes for the ratchet mechanism too. Where is the ratchet mechan- ism? Safely encased in that neat GOODELL-PRATT COMPANY, GREENFIELD, MASS., U.S.A. GOODELL PRATT 1500 GOOD TOOLS IS) This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. POPULAR SCIENCE MONTHLY red enameled drop forging just above the chuck shell. Some- thing entirely new—a patented feature—and this ratchet mech- anism is as sure and as husky as it is different. Can you imagine yourself stripping a hardened tool steel dog 114 inches long which bites into teeth broached in a forged steel head? Just try to do it! Need we add that the heavy steel sweep is nicely nickel plated, that the head and handle are polished rosewood, that the steel clad head is set on roller bear- ings? Only the best of fittings could have a place on a brace like this one. You can’t find a better bit brace. Closely priced, too—$6.20. Good hardware stores sell it. © Unique Wooden Vise Is Aid in Keeping Saws Sharp ‘TBE handsaw filing vise or clamp illys. trated can be made of scrap lumber to be found in any home workshop ang will prove both substantial and op. venient. The jaws are 28 in. long, so that the entire saw can be clamped at one setting. When one side is sharpened, the saw and yige are turned bodily to file the other \ side. The frame jg high enough to be placed on the floor and leaned against a bench in the best light. Placing one foot on the lower rail steadies the vise during filing, Note that the wire is bound around the V-shape notches to prevent the wood from splitting.—W. L. CLAMP 28” LONG How the saw fil- ing vise is made How to Reline Auto Clutches (Continued from page 90) assembly when dismantling. In certain types of construction, notably the single plate, the clutch js assembled within the flywheel and will remain in the flywheel after the trans- mission has been removed. In this type it will be necessary to remove the plate bolted to the flywheel and thus get at the clutch facings, which as a rule are not fastened to any of the parts. As a rule, in the multiple-plate or disk type, two friction disks are riveted to a steel plate that turns with the flywheel. When replacing these facings, which may be secured either from the supply houses or the dealer, care must be exercised to see that the rivets used are brass or copper and well countersunk so that there is no chance of their coming into contact with the steel faces of the driving disks. Most clutch facings come from the factory with properly countersunk or counterbored holes. If they have not been provided, however, care must be used in drilling them so as not to get them too deep. Any badly scored unlined clutch disks should be replaced. When reassembling the clutch plates, use care to have them alined so that they may be placed on the pins of the flywheel or in the grooves that are pro- vided. It will be necessary to use the press or a jack to put pressure on the spring, or springs, in most cases. Make all connections that were re- moved preparatory to the work. It isa good plan to repack the universals with grease, clean and repack the pilot bear- ing, and properly lubricate all parts needing such attention. When the job is finally assembled, it may be necessary to readjust the clutch pedal to the floorboard position. Mr. Kuns’ next article will be ‘‘What Makes My Car Jump Out of Second Speed?’”’

Page 87

“Aid in rp amp illus. 2p lumber shop and and con- 1g, SO that e Saw can ed at one When One harpened, and vise ed bodily the other 1e frame ig ugh to be n the floor ed against in the best lacing one the lower sadies the ‘ing filing. around the the wood ‘lutches

nstruction, > clutch is el and will the trans- n this type e the plate is get at the ule are not late or disk ‘iveted to a ne flywheel. , which may pply houses exercised to re brass or nk so. that coming into ‘the driving come from intersunk or y have not re must be , not to get ored unlined ed. lutch plates, ned so that pins of the hat are pro- y to use the ssure on the -aSeS. lat were re- ork. It isa iversals with 1@ pilot bear- te all parts assembled, it ist the clutch tion. vill be *‘What t of Second

October, 1925 | SELECT THE OBEDIENT SLAVE TO

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Upon request, we will gladly mail you descriptive folder.

PAARL ‘e

POPULAR SCIENCE MONTHLY 93 Dn Stations thousandsof milesaway,or powerful near stations can be entirely and instantly iso- lated from interference. This degree of finer selectivity is not the only triumph achieved by APEX scientific engineer- ing principles. Full volume, wider range, greater clarity have been acquired and are enthroned in a setting of exquisite beauty of design and finish that place APEX Cabinets in the highest ranks of the finest furniture. Only a dependable merchant is given the APEX dealer franchise. Your APEX dealer will gladly make a personaldemonstrationof APEX Quality Radio Apparatus.

harp—so, too, do you,who operate an APEX Radio Receiving Set, select and con- trol the sound waves wafted through the air. Also makers of the famous APEX Vernier Dials and APEX Rheostats, which are sold

VITY — DESIRES

Just as the skillful fingersofatrained musician select and control the sensitive, vibrant strings of a

oO iy cS Wy, Wii W777)

EU ME HL TU Md, AL UL AT TL TY

APEX ELECTRIC MFG. CO. 1410 W. 59th St., Dept. 1003 hicago by every good dealer in Radio.

Apex Baby Grand Console Price $225

a ae Tm a Wee py yi Ce roy \ / | ) Nie ah) j attra *®

Apex Super Five Price $95 without accessories

Apex Console Entertainer Price $27.50

Apex Utility Apex DeLuxe — Radio Table Pri Price $22.50 Price $75 rice $135 Prices West of Rockies slightly higher. Canadian prices approximately 40% higher.

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. Scanapaentel

Page 88

94 POPULAR SCIENCE MONTHLY When you see a “Hex’~think of BLACKHAWK} eee y~ Work Hounds OING after hidden nuts and bolts with a set of Blackhawk “Q.D.’s” is like putting bloodhounds on their trail. They like the work, and they never quit! Have your dealer show you a Blackhawk “Q.D.” set designed especially for your own make and model of car—it handles every nut you need ever worry about. Downright quality is built into every Blackhawk “Q. D.” set. Tough steel sockets, balanced handles built for the job, comfortable, hand-fitting grips, and a satiny black finish baked on to stay. If your dealer is not stocked yet, write us direct. BLACKHAWK MFG. COMPANY : _ Cormerly American Grinder Mfg. Co.) Figg ionmenon i ’ manufacturers of Black- hawk Water Pumps for Fords, | | Rranill icd October, 1925 _is used in auto curtains, are cut the same $$ Old Chair Used as Support for Bed Table ~ ILLNESS a bed table invariably adds to the patient’s comfort and saves work on the part of the nurse, yet rarely is it considered worth while to pur- chase a special hospital table for home use. A good substitute can be constructed by sawing off the legs of a discarded chair SHELF * BRACKETS SLIDES UNDER BED The table board is attached to the back of the chair with heavy shelf brackets short enough so that the seat will slip under the edge of the bed. To the back of the chair fasten with shelf brackets a board the size of the seat in such a posi- tion that when the chair seat is slipped under the bed the table extends in front of the patient.— MINNIE BRITT RIGGLE. Bavaria, Kan. Writing Is Erased Instantly from Everlasting Pad LyAvVe you a place in your office or workshop for a scratch pad that is everlasting and indestructible? One may be made by coating a 1/i6-in. thick sheet of black fiber or composition with paraffin. A sheet of aluminum will do nicely if it is given a heavy coat of dull black paint be- fore being waxed. A sheet of tough, yet very thin tissue paper and a sheet of thin celluloid, such as WRITING DISAPPEARS SHEET WITH BLACK SURFACE HEAVILY WAXED WHITE TISSUE i TRANSPARENT CELLULOID Notes made on the celluloid surface vanish when the celluloid and tissue paper are raised WRITING POSITION width as the black base, but about \ in. longer. The illustration clearly shows how the three sheets are assembled. The paper and celluloid are glued together along the edge farthest from the binding. To write, use a pencil or any stylus, such as a nail or match. To erase the writing, merely lift the projecting edge of the celluloid sheet.—A. E. WILLIAMSON, Cleveland, Ohio. (S) This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

Page 89

tober, 1925

variably rt and rse, yet to pur- me use. tructed ed chair

ER BED | back ckets will slip : back of ickets a 1 a posi- slipped in front RIGGLE. ntly d office or 1 that is ne may ick sheet paraffin. ly if it is paint be- in tissue |, such as / vanish re raised the same ut 1% in. ly shows led. The together binding. y stylus, erase the g edge of LIAMSON,

siaviyped Photos Squeegeed in Old Clothes-Wringer

HE amateur photographer, who makes very glossy prints by ferrotyping on a Japan tinned metal plate, often finds the rolling of the prints by hand tire- some. Where many prints are to be made, an old clothes-wringer is useful. The best results are obtained by placing the wet prints face down on the plate and then putting one blotter over the prints and another underneath the plate. Only moderate pressure is necessary.

Unique Method for Cutting and Folding Neat Envelopes ‘ Gyecred and easily obtained as are en- velopes, it probably has happened again and again that you have not had an envelope at hand of exactly the right size or quality to suit some special purpose. This predicament will never cause any delay, however, if you know the trick of making a square-cornered envelope with nothing but paper and scissors. Any paper can be used. Good quality letter or sample paper may be used for small envelopes, and drawing, manila, or il Dr ? CUT wz

Wl-----

COMPLETED \ 2 FOLD a cuT - Eight steps in making large or small en- velopes without the aid of ruler or square

heavy wrapping paper for large ones.

| The sheet, say an 814 by 11 in. letter- | head, is first folded from left to right on the vertical center line. Next, it is folded from the bottom up (2) to bring the bot- tom edge within 1 in. of the top edge. Next fold in the center (3) to get a crease for cutting (4). Open out and cut the outline of the flaps (5), as shown by the heavy dotted lines. This is easily done without drawing guide lines. Open the sheet at the lower fold (6) and cut off the superfluous flaps to give the completed form (7). The envelope then is folded (8). The small retaining flap, when folded over, holds the envelope is shape while the letter is being inserted. Paste is applied to the top flap when the envelope is used, or it may be applied and left to dry, as on commercial en- velopes. Pasting down the top flap seals the entire envelope, although the side flaps also can be pasted if desired.—J. A. FITZPATRICK, Milesburg, Pa.

POPULAR SCIENCE MONTHLY

Be SURE of your Hardware RE you one of the home A buyers who know good hardware? Cheap hard- ware of plated steel comes out of its box clean’. and fresh. It looks good—for awhile—but get beneath the surface. Cheap hard- ware never lasts. The tarnished metal; the discoloration on the door pointing a telltale streak of rust at the hardware that caused it; the faulty working of the lock —all these, in a few weeks or months, tell you the story of cheap hardware— but then it’s too late. How much better it is to be sure. Look for the mark YALE. Tell your architect or builder that you want Yale Hardware in solid brass or bronze. Make sure the name YALE is on it. That is the mark of good hardware worthy of your home. For sale by dealers everywhere. The Yale & Towne Mfg. Co. Stamford, Conn., U. S. A. Canadian Branch at St. Catharines, Ont.

IS) This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. YALE MADE !S YALE MARKED

Page 90

POPULAR SCIENCE MONTHLY So, U.S.A. «TRADE MARKI Striking and Conclusive Test of the Steel in NICHOLSON Files! Twenty-five years ago, an Osage In- dian in Oklahoma made this razorfrom a NICHOLSON File of regular stock, the braves using it to shave around the scalp lock. Now, from the South, a man sends us sam- ples of superior quality razors he is making from NICHOLSON Files. Incidents like these, twenty-five years apart, prove conclusively that year in, year out, only the best file steel is used in NICHOLSON Files. For shop or home, there is a NICHOLSON File for every need. Your hardware dealer will gladly help you select those best suited for your purposes. @ NICHOLSON FILE Co. PROVIDENCE, R. I., U.S.A. NICHOLSON FILES ~a File for Every Purpose ing ball. by A. J. Drake, of Sturgis, Mich., is 1 1/16 © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. Platform across Large Tub ’ Supports Baby’s Bath MOrtHeERs who bend over the bathtuh in giving baby a bath can make jt easier for themselves by having a platform or bench constructed to go across the top of the tub, as illustrated. The wooden slats are fastened together by a strip of wood on the under side at each end. Baby’s tub is placed upon the platform, which can be slid to one end of the tub or removed ey & —_ not in use.—J. G. P. Ball and Screw Provide Novel Lock for Curious Puzzle you can make the curious little toy bank, jewelry box, and puzzle illus- trated below with nothing but a piece of waste wood, a wood screw, and a bear- The size of the original, which was made by 1 11/16 by 33¢ in. over all. The lower block, containing the storage space, is lin. deep. The wood screw is 15% in. No. 6, LOCKING PIN. IN THIS’ \ POSITION BALL ALLOWS CENTER PIECE TO SLIDE & FREE FROM PIN STORAGE SPACE This puzzling little box can be opened only when turned to get the ball-out of the way and the steel ball is 3/16 in. in diameter. Of course, the puzzle may be made larger or smaller. To open it is more of a trick than ap- pears and even when some one acci- dentally stumbles upon the combination, he usually cannot succeed in closing the lid again. Hold the box in the position shown in the upper drawing and turn it away from you until it is upside down. Then pull out what is now the lowest piece until it is at right angles to the rest of the box. It then is possible for you to slide the middle section to the right sufficiently to allow it to clear the locking pin, as indicated in the small drawing at the left. —J. B. Ros WICK, Sturgis, Mich.

Page 91

bathtub make it olatform | the top together ’ side at ipon the e end of n not in Novel zle ittle toy zle illus- _ piece of a bear- vas made is 11/16 ‘he lower e, is Lin. n. No. 6, E SPACE ed only he way diameter. ide larger than ap- yne acci- bination, osing the shown in way from ‘hen pull until it is box. It he middle 0 allow it licated in B. Ros " October, 1925 OMe Workshop Cigar Boxes Used as Drawers for Home Workshop Cabinet HE home workshop cabinet illustrated is a desirable substitute for the usual array of cardboard boxes, cigar boxes, cocoa tins, and tobacco cans so often used by the amateur craftsman or handy man for holding screws, nails, washers, bind- ing posts, hard- ware, and other supplies. Any wood may be used for the cabinet. The exact di- mensions of the main parts are shown. The Y-in.-thick back is nailed 18 REQUIRED EQUAL TO THICKNES: OF BOX SIDES, Ms 24 Yel ball 2% ss 2%" ‘abot bev be N TOP AND BOTTOM The main parts necessary in constructing a handy cabinet for hardware and supplies intoa 4% by Win. rabbet cut in the two end pieces. The top piece is 34 by 101% by 21% in., with three edges and the two front corners rounded off. The upper and lower moldings give a finished appearance to the cabinet, and in addition four lengths of 34-in. half-round molding are bradded to the front edges of the upright members. The 18 drawers are made of cigar boxes. One end of each box is removed and re- placed with a front piece made as indi- cated. This saves a great deal of work. The drawers are 2 3/16 by 5 3/16 by about 9in. Kettle knobs form the handles. Restringing Beads on Wire BREAKAGE of the string holding arti- ficial pearls and other necklaces can be prevented by restringing with very fine steel wire. I have used surgeon’s snare wire intended for tonsil work, but I understand that the E string used for mandolins is the same size and answers very well. Each end should be looped through the link in the clasp and doubled back to pass through about six of the end beads. The extreme end of the wire then is turned up to form a hook-like catch. —H. J. BLake, M.D. POPULAR SCIENCE MONTHLY Pride of the Street RYE TL LAG MULE: Every finish correct as specified on the Household Painting Guide i. pey can be true of your home if you take advantage of the origi- nal beautiful Color Suggestions provided by Sherwin-Williams and consult the Household Painting Guide. You will find these at Paint Headquarters, the up-to-date store in your community. If you cannot locate Paint Headquarters write us at once. The Sherwin-Williams Co., largest paint and varnish makers in the world, 659 Canal Road, Cleveland, QO. SHERWIN- & PAINTS AND EHOLD PAINTING GUIDE WILLIAMS VARNISHES TO PAINT— |TOVARNISH—! TO STAIN— |TOENAMEL SURFACE USE PRODUCT USE PRODUCT USE PRODUCT USE PRODUCT NAMED BELOW NAMED BELOW NAMED BELOW | NAMED BELOW AUTOMOBILES..... S-W Auto Enamel at alana S-W Auto Enamel AUTOMOBILE TOPS] S-W Auto Top and S-W AND SEATS... .... Auto Seat Dressing SWP House Paint S-W Concrete Wall Finish Old Dutch Enamel CEILINGS, Interior... Flat-Tone Scar-Not Varnish S-W Handcraft Stain Floorlac Enameloid Exterior .. SWP House Paint Rexpar Varnish S-W Oil Stain Old Dutch Enamel CONCRETE ... . |] S-W Concrete Wall Finish DOORS, Interior ..... SWP House Paint Scar-Not Varnish Velvet Finish No. 1044 Floorlae S-W Handcraft Stain Enameloid Exterior... ... SWP House Paint Rexpar Varnish S-W Oil Stain Old Dutch Enamel SWP House Paint Metalastic S-W Roof and Bridge Paint S-W Preservative Shingle Stain FLOORS, Interior (wood) .... S-W Inside Floor Paint Mar-Not Varnish Floorlac S-W Inside Floor Paint -Concrete... S-W Concrete Floor Finish S-W Concrete Floor Finish Porch S-W Porch and Deck Paint 4@\| FURNITURE, Indoors Enameloid Scar-Not Varnish Floorlac Old Dutch Enamel Interior ......... ere Flat-Tone Scar-Not Varnish Velvet Finish No. 1044 FI S-W Oil Stain joorlac H Porch Enameloid Rexpar Varnish S-W Oil Stain Enameloid We * | : ae a SWP House Paint Rexpar Varnish gt Fs Old Dutch Enamel 1: || LINOLEUM .........|| S-W Inside Floor Paint Mar-Not Varnish S-W Inside Floor Paint H ; Flat-Tone | RADIATORS........ S-W Aluminum or Gold Enameloid 1 aint 4 || ROOFS, Shingle...... S-W Roof and Bridge Paint a Metal ...|| Metalastic “ He ny Sor Composition . || Ebonol ingle Stain SCREENS .......... S-W Screen Enamel S-W Screen Enamel See S-W Family Paint Rexpar Varnish” Floorlac Enameloid 4 || WALLS, Interior Flat-Tone Old Dutch Enamel ai} (Plaster or Wallboard) || SWP House Paint Enameloid 2 WICKER........... Enameloid Rexpar Varnish Floorlac Old Dutch Enamel : WOODWORK SWP House Paint S-W Handcraft Stain Old Dutch Enamel A Enameloid as © This seal on a radio or tool advertisement signifies the approval of the INSIIIUTE OF STANDARDS See page 6.

Page 92

POPULAR SCIENCE MONTHLY October, 1935 Building for America’s growth The early builders of America made their houses of rough hewn logs or of stone or adobe lifted from the earth. Settle- ments grew to towns, towns to cities. Small stores and shops were built, and these in turn were torn down to make room for ._ bigger ones. Roads, bridges and railways were constructed. Factories and skyscrapers were erected. And so, swiftly, the America of today appeared, still growing. | | Mae Tone Works showy In the midst of the development came the telephone. No one can tell how much of the marvelous later growth is due to it—how much it has helped the cities, farms and industries to build. We do know that the telephone became a part of the whole of American life and that it not only grew with the country, but contributed to the country’s growth. Communication by telephone has now become so important that every American activity not only places dependence upon the telephone service of today, but demands even greater service for the growth of tomorrow. , AMERICAN TELEPHONE AND TELEGRAPH COMPANY AND ASSOCIATED COMPANIES ky BELL SYSTEM L One Policy, One System, Universal Service KEY~ ELECTRICITY Audels Handy Book of Practical Electricity, 1 Vol. $4 Complete in One Pocket Size, Flexible, Bright Red Leather Volume A simplified ready reference, giving complete instruction and inside information. Handy to use. Easy to understand. For Engineers, Professional Electricians, Students. A reliable au- thority and a handy helper for every electrical worker. INFORMATION COMPLETE COURSE FOR HOME STUDY 3 The 1040 pages and 2600 dia- Learn more and you willearn more. Know the ‘acts in fia srams give accurate, up-to-date Electricity. Thiscouponis youropportunity. Use it now! and complete information on— - === = eee8e8eee2 = =e eee eee ee Rules and Laws. RADIO, Storage | {J -] fsa The. Audel Co, 65 W. 23 St, NewYork Batteries, WIRING DIAGRAMS, } Please send me Audel’s Handy Book of Power and House Wiring, Auto- 5 B9t{"ir Tih! Practical Electricity for free examina- matic ‘’Phones, Auto Ignition, | tion. If satisfactory, I will send you Motor Troubles, ARMA- 1 COUPON $1 in 7 days, then $1 monthly until $4 is TURE WINDING, Cable Splic- paid. ing, Elevators and Cranes, Sign Name ati a ; + pomenes Transformers, Practical 1 COCO cer cccecccccccccccecccecceecocceecoNe is Handy Book of Electricity] Management, ernApplications is all that you slaim for it and then ~READY 1 REFERENCE on every elect | Address Gent helo many things | fenee ie kexts font CRATE Bey ' Kactuplttion.;...........s6+. tee -Woerner,Jr.,Lake NJ.) T. * e eceen eee use 8 employed by .................ccccccceee 10T34 | have a good looking grain. You will | molding to go around the base. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. | the front edge of each piece will look well How to Construct a “Two-Tone” Radio Cabinet By R. A. Kelly ANY radio fans, after taking the utmost pains in assembling a fine receiver, are content to place it in a cheap, commercial cabinet with a thin, easily marred and relatively unattractive finish. Certainly any one who can assem- ble a complicated radio set can build him- self a suitable cabinet, for little wood- working skill is required and the appli- cation of a really fine finish is merely a matter of knowing what to do and having plenty of patience. The cabinet illustrated holds a set operated by dry cells, which go into the small side .compartments. In this cage the panel is 7 by 14 in., but the cabinet can be made to suit a panel of any size. One of the most satisfactory substi- tutes for genuine mahogany or walnut igs whitewood, because it is easy to work and | This cabinet, which takes a 7 by 14 in. panel, has two compartments for dry batteries takes a mahogany dye or wood stain very well. In purchasing the wood, be sure to pick out pieces that are not warped and need a 14 by 12 in. board 8 ft. long and a 34 by 12 in. board 3 ft. long, as well as 8 ft. of any suitable 34 by % in. stock After the base has been cut to the finished size, which in this case is 34 by 10 by 27 in., nail the molding neatly around it, mitering the corners. Then cut the other pieces as shown, being sure that the ends and the partitions have the grain running from top to bottom, so that when finished. Keep the back, ends, and front 14 in. in from the edges of the - baseboard. Fasten the back, ends, and partitions to the base with 114-in. flathead wood screws. All other joints may be held with brads, the heads being punched well into the wood. A piece 1% by 1 in. by 2 ft. 214 in. is nailed across the front at the top to act as a brace. Small strips are placed so as to form stops for the panel and the two doors of the battery compartments. If the doors are made a fairly tight fit they will stay in place by themselves. If de- sired, however, common ball-and-socket friction catches may be used to hold the doors in place, these being easier to apply and more convenient in use than hinges (Continued on page 104)

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er, 1925 ig the a fine eit in _ thin, active ssem- 1 him- wood- appli- rely a 1aving a_ set to the S case abinet size. substi- nut is | *k and yanel, teries n very sure to od and u_ will ig and well as - stock to the 34 by neatly Then ig sure ve the 30 that »k well VY in. board. ions to wood e held inched 4 in. is yact as » as to he two ts. it they If de- -socket old the > apply hinges October, 1925 POPULAR SCIENCE MONTHLY In Hospitals and Homes Zvcos THERMOMETERS Protect the Health of the Nation N ALL hospitals where the beds filled with patients stretch down the wards in long, orderly rows, the thermometer is the compass used by the doctors to help guide their patients through the dangerous channels of sickness. Nowhere do Jycos Thermometers play a more vital role than in hospitals wheré the carefully charted temperature of the patient is the first thing the doctor looks at when making his rounds. The easily read figures, the pro- portion of tube to bulb, the perfection of the magnifying lens and the ease —consistent with safety—with which the column of mercury may be shaken down after use make the Zycos Fever Thermometers popular with doctors and nurses. Important as they are in hospitals, Jyeos Fever Thermometers are equally important in the home to guard the health of the children and the older members of the family. To Manufacturers The same accuracy that makes Zreos Fever Thermometers the protectors of the health of the nation is available to manufacturers of all products that go through processes demanding accuracy of temperature control. In the Hees line ms 8000 different kinds of Heat Indicating, Recording and Controlling Instruments—the Sixth Sense of In- dustry—there are instruments that will help you produce absolutely uniform products. Whether you bake bread by the mile, make candy by the ton, can fruits or vegetables by the carload, or use heat in your manufacturing processes for any purpose, it will ° pay you to learn how other manufacturers are using the Sixth Sense of Industry to get the uniform results essential to manufacturing on a large scale. Informative literature on any type of instrument will be sent you on request. Or our engineer will consult with you on the application of Zeos to your particular manu- facturing problem. Taylor Instrument Companies Main Office and Factory ROCHESTER, N. Y. . : U.S.A; Canadian Plant: Jycos BUILDING, TORONTO SHORT & MASON, LTD. Manufacturing Distrib- utors in Great Britain. iycos Office Thermometers An aid in promoting human efficiency Zcos Bath Thermometers To enable you to get the most good from your bath. Taylor Home Set Bake Oven Thermom- eter, Candy Thermom- eter, Sugar Meter. The secret of accurate re- sults in cooking. Tycos Wall Thermometers To help you maintain a temperature in your house conducive to good health. Toler Quality Compasses To show you the right way in unfamiliar country. Zycos Fever Thermometers A necessity in every home. Tycos Stormoguide Forecasts the weather twenty-four hours ahead with depend- able accuracy. Tycos Hygrometer To enable you to keep the humidity of the atmosphere in your home correct at all times. Your dealer will show them to you. Ask us, on a postal, for booklets on any of the above. Jycos Sphygmomanometer, Pocket and Office types Jece Urinalysis Glassware. Jycos Fever Thermometers. Bulletins on request.

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POPULAR SCIENCE MONTHLY October, 1925

It is not a “Hot Shot’ unless it is an Eveready Columbia

WHEN you ask for a “Hot Shot” Dry Battery, it will pay you to make sure you get one. Any group of dry cells con- nected in a package is not a Hot Shot. “Hot Shot” is a trade-marked name and means only Eveready Columbia. Hot Shots come in three sizes, con- taining 4, 5 or 6 cells, giving 6, 7% or 9 volts. In a neat, durable, water-proof steel case New York with convenient carrying han- dle. Every one is labeled . “Eveready Columbia Hot Shot.” Experienced battery men prefer these batteries be- cause of their superior ser- vice—they last longer. It will pay every dry battery user who needs 6, 714 or 9 volts to ask for Hot Shots and to make sure of gettingthem. There isan Ever- eady Columbia dealer nearby. Manufactured and guaranteed by NATIONAL CARBON COMPANY, [we . San Francisco Canadian National Carbon Co., Limited, Toronto, Ontario

gas engine ignition motor boat ignition tractor ignition starting Fords lighting tents and outbuildings doorbells buzzers running toys telephone and telegraph heat regulators ringing burglar alarms protecting bank vaults electric clocks calling Pullman porters firing blasts

EVEREADY COLUMBIA ~~. Dry Batteries -they last longer

AGENTS spit PLUG Visible Flash Just Out— Amazing Invention— = Beacon Lite Spark Plugs. You —=a see the flash of each explosion in — the eg Tells which are fring —_. | SS isince Sacked. Wor * Gerful en p ech coining money. ring 904 WEEK

Easy to make with new sure-fire plans. Sells on autoowner. Phillips, Ont., bes “Gold 2 dozen today 9 done Jee us ozen,”” e i intent on Offer and F FREE ai oa to introduce these ie spark territory. CENTRAL PETROLEUM CoubaNyY 1630 Century Building Cleveland, Ohio

CORONA FOUR With standard office keyboard—an office typewriter in port- . able form. < Write for literature. y Corona Typewriter Co., Inc’, 112 Main St. , Groton, N. oe. be

~~ Your Ideas 7 oney Wade Bencn-Lathe Get cash for spare time, making tterns, work- ~ ing models, inventions. yuan) Save and et mane:

pact. ies at oaunly’ low prices. THE =. —— Dept. PS-5S, 120 Liberty Str lete line of

New York

[és Home Worlssligiy A **Two-Tone”’ Radio Cabinet (Continued from page 102)

for this purpose. Six ordinary dry cells wil] fit in one compartment and two small size 45-volt B batteries will go into the other, When the construction is completed, sandpaper the cabinet thoroughly, finish. ing off with No. 1% or finer paper. For finishing the cabinet you wil] need 14 pt. each of dark mahogany and light oak wood dye or stain, although only a small portion actually will be used; 1 pt. white shellac, 1 pt. denatured alcohol, a little putty, a few sheets of No. 00 or finer sandpaper, a little powder- ed pumice-stone, 14 pt. lemon oil, one soft bristle brush, and one small cheap artist’s brush. Dust the cabinet well and apply the mahogany stain to all surfaces except | the doors. Do one section at a time and | work quickly to avoid laps. | While the cabinet is drying, draw A in. -wide border around each door \4

| in. from the edge, using pencil and ruler,

~ MOLDING %. : NAILED ON a Details of the cabinet, the dimensions of which may be modified to suit any panel Then draw the diamond-shaped design in the center, keeping the points about 1 in. away from the edges. With pocket- knife and ruler cut quite deeply on the pencil lines and then enlarge these cuts with a sharp pointed file or other tool. With the smaller brush, color the back- ground of the doors as shown, using the mahogany dye. Be careful not to let the color run into the border or the diamond. The indentations previously made are to aid in keeping the color

from spreading. | Clean the brush and apply the light | oak stain to the remaining areas, which | are to be very light in color. It will do almost as well to stain these with very light mahogany dye. This can be made by greatly diluting the dark dye with either turpentine or alcohol, as specified by the manufacturer. In that case the cost of the light oak stain can be saved. The idea is to have a decided contrast between the design and the background on the doors, giving the two-tone effect now so popular. It is well first to prac- tise applying these two tones on a scrap piece of wood. Color a little putty with the mahogany stain until it matches the cabinet and fill the nail holes and any open joints.

(Continued on page 106)

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

| J

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net lis will ill size other, dleted, finish- 1 will y and hough ill be atured ets of »wder- 1, one cheap ly the except ne and raw a | oor \ | ruler. 4 ms of panel design ; about pocket- on the se cuts ar tool. 2 back- ing the to let or the viously e color e light , which will do th very e made re with pecified ase the . saved. -ontrast ‘ground e effect oO prac- a scrap uhogany net and POPULAR SCIENCE MONTHLY . joints. Gp (Patented) (for Storage or Dry Batteries) j=l | at fl Licensed under Blackmore Patents and Patents Pending, Hozan Patent No. 1014002 Revolutionizing . Radio Operation THE NEWEST THING IN RADIO! ‘‘“NO-DIAL”’ so simple in operation, so positive in performance, is just what you want Dials are gone forever! Old-fashioned—obsolete! refer to them as primitive—pre-historic—‘‘old-as-the-hills!”’ Away with trouble, complicated tuning and puzzling operations! Scrap your log book! Forget your past disappointments. For radio is SIMPLICITY itself now! Just what you predicted and everybody expected. You, who have waited for the ‘‘grief-less,” and ‘‘worry-less’” radio receiver, can buy NO-DIAL safely. VISIBLE STATION RECORD The NO-DIAL brings in stations far and near by merely rotating the cover. Each station comes in at a certain point. As stations are received they are recorded right on the cover (fig.1) and thereafter they will always come in at the same point. Thus you have a permanent and visible station record which is positive and unfailing. IT’S BEAUTIFUL The NO-DIAL represents a complete departure in radio set design. It is housed in a compact, circular case fin- ished in popular brown crystalline, a perfect match for most high grade loud speakers. Nothing to spot, scratch or mar. Easily cleaned with a damp cloth. Finally, it’s trouble-proof and GUARAN- TEED. Five Tube No-Dial for Storage or Dry Batteries Type 5 and Type 5-D (Less Loudspeaker and Accessories) Retail Price $98 ” If your dealer cannot supply you write us for literature giving dealer’s name and address. A The Ohio Stamping and Engineering Company, Dayton, Ohio, U. S.A. c They served their purpose in the Permanent Visible Station Record. Harshness and interfering noises are A touch of the finger brings 'em in. absorbed and never reach the ear. NO-DIAL with cover removed. demonstration. You'll be amazed. ‘radio pioneer days.’” Now up-to-date fans LOUD AND CLEAR AS A BELL The tonal qualities of the NO-DIAL will please everyone, due to the fact that they are directly caused by our latest combination in resistance cou- pled amplification. The tonal qualities are so sweet, so clear, so mellow! Volume is regulated with a _ control lever. Far distant stations come in al- most as distinctly as local. Results are positive and instantaneous. Tube for tube, the NO-DIAL recog- nizes no superior, and on test it has out-performed many higher priced receivers. The NO-DIAL will do every- thing any other single control set will do, and more, as regards fine volume, long range and clarity of tone. See your dealer TODAY and ask for a 1S) This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

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POPULAR SCIENCE MONTHLY Oc tober, 1925 500 E. Pear! St., THE KODEL MICRO- PHONE LOUD SPEAKER is an exact replica of the transmitting microphone used in broadcasting. The effecient Kodel reproducing unit, with an ingenious new snail-shell horn, mounted inside the microphone case, produces a remarkably clear, full-toned volume. Non-vibrating tone chamber eliminates distortion. The $15 model incorporates the new Kodel, Jr. unit; with the large Kodel unit, $20 Radio dealers everywhere have them THE KODEL RADIO CORP Cincinnati, O. Design Patented LOUD SPEAKER Dept. 108 LEARN 10 ELEcTRICITY A twenty-five cent book, ‘‘Electricity and Magnetism”’ key to elec- trical knowledge and small motor Cc building. For a short time only Port Chester, N. Y. Knapp Electric Corporation LATEST WHOLESALE, RADIO CATALOG mas yd send name TODAY for big 48-page catalog of latest radio goods at Wholesale. Live dealers and agents wanted. STANDARD RADIO CO., 104 East 13th, Kansas City, Mo. The Pilliod Lumber Co., Swantou, Ohio ® Tool Cases for Machinists, Car- penters and Tool Makers; none better; thirty styles. Quarter- ed oak and metal cov- ered, Ask for booklet. **Built for Service’’ HAVE You An INVENTION? Ifso the WORLD PROGRESS will send you upon request sample copy Free containing Suggestions to Inventors as to Inventions Needed. We invite manufacturers to address us regarding inven- tions they want. Subscription for one year 60 cents. WORLD PROGRESS PUB. CO., INC. Room 202 Victor Bidg. Washington, D. C. — | dite ome Workshop A **Two-Tone”’ Radio Cabinet (Continued from page 104) Pour white shellac into a dish and adq about one-third as much alcohol. Apply this to each section separately, using long strokes and working very quickly as the shellac sets almost at once. jy not try to go over or touch up any places you have missed. This one coat of shellac is sufficient for the inside of the cabinet except the inside surface of the cover, which should be finished fairly well, as it will show when open. Give the cabinet four or five more coats of shellac, sandpapering and dusting thoroughly between each coat, as this is the secret of obtaining a good finish, The removable battery compartment doors, which are given an attractive two-tone finish The last two coats of shellac need not be thinned. Allow several hours between coats for the shellac to dry and let the last coat stand overnight. The next step is to polish the cabinet by saturating a clean, soft rag with the lemon oil, sprinkling a little powdered pumice-stone on the wood and rubhing it briskly with the oily rag until the finish appears to be smooth. This takes off the high gloss, but gives a rubbed effect with a moderate gloss such as often is seen on the most expensive furniture. Remove all the grit with a clean, dry rag. Anickel, silver, or gold-plated knob is fastened in the center of each door. Finished in this way, the cabinet will always maintain its excellent appearance. Simple Trick Aids in Squaring Picture in Its Frame N FRAMING PICTURE pictures, the —=- placing of the back piece of cardboard My ‘ or wood often moves the picture itself a trifle so that it is no longer square with the frame. Every has attempted to frame pictures has experienced this diffi- culty. It can be overcome by a simple trick of boring or cutting holes in diagon- ally opposite corners of the back. Having placed the picture and back in the frame, drive in a few brads lightly, turn the frame over and then center the picture accurately by shifting it as necessary with the finger-tips through the holes. Then finish bradding down the back.—LovulIs SCHNEIDER, Clinton, Mo. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See Page 6.

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and add Apply yy using quickly, t doors, 1e finish 1eed not between 1 let the > cabinet with the owdered ibhbing it he finish takes off ed effect often is urniture. ean, dry ted knob ich door. inet will yearance. juaring e ICTURE this diffi- a simple n diagon- . Having he frame, turn the e picture sary with s. Then :. —LOovuIs POPULAR SCIENCE MONTHLY 107 Build the phenomenal new type radio with one of these kits Everyone wants one of these revolutionary receivers that are amazing engineers with their results. Designed on a newly discovered principle. Now you may build your own in a surprisingly short time from one of these remarkable kits. Send for new free book that tells how. The new Erla Circloid Five Factory Bilt Kit—as you receive it. Ready-cut, flexible, solderless leads and charts enable you to wire it in an evening. Price $49.50 ERE is an easy way to have the new radio that is astonishing radio fans everywhere. You make a big saving and have the fun of building your own set besides. It takes only a short time—from 45 minutes to an evening—depending on the kit you select. There are one to five tube kits at strik- ingly low prices. No wire bending or soldering. Merely set up the parts, then attach a few ready-cut flexible eyeletted leads and the job is done. The amazing new inductance principle found in these kits is based on a different kind of coil—the Erla *Balloon *Circloid. It belongs to Erla alone. No other set regard- less of price, can offer it to you. Four strik- ing advantages result. 1, Greater Distance. Circloids have no measurable external field to affect adjacent coils or wiring circuits. This makes pos- sible higher amplification in each stage, with increased sensitivity and greater range. *Trade Mark Registered 2. More volume. Higher r. f. amplifica- tion enables Circloids to bring in distant stations scarcely audible in ordinary sets with volume on the loud speaker to fill an auditorium. 3. Increased Selectivity. Circloids have absolutely no pick-up qualities of their own. Only signals flowing in the antenna circuits are built up. 4, Finer Tone Quality. The self-enclosed field positively prevents stray feed backs between coils. Hence no blurring or dis- tortion. Tones are crystal clear. Write for free information on kit —also book See how a few minutes of fun will give you the newest and most phenomenal set known to radio science. Examine it at any Erla dealer’s, or send the coupon for full infor- mation, illustrations and diagrams contained in the remarkable book, “Circloid Hookups.” 1 i 1 i 3 i t i i Dealers—Exclusive franchises are available to high class ; : dealers in localities still open. Write or wire immediately. ' ‘ | t | | Pf | c t "sy , This sign identifies authorized Erla distributors. All are cquipped to give complete radio service. y * * * Erla Kit No. K-10 Consists of 3 Erla Balloon Circloids (1 coupler and 2 transformers). Full instructions for installing on your present re- ceiver are in- cluded. Price $12. Erla Kit No. K-13 Consists of 3 Erla Balloon Circloid Coupler and Trans- formers and 3 .00035 15-plate Erla Mini- loss Condensers. Complete instruc- tions for installing in each box. This combination gives you a splendid 5-tube receiver, Price $21.50, Erla 3 Tube Cir-Kit Contains abso- lutely every part used in the construc- tion ofa3-tube Erla receiver, from drilled and engraved Bakelite panel and stenciled baseboard to wood screws and wire. Every part tested and approved in our labora- tories and guaranteed. NOW FREE Get this book telling about the newest scientific radio discovery. See the many circuits in which it can be used. Make the tests that prove the four great advan- tages it brings. The edition is limited, so write immediately. Electrical Research Laboratories, 2500 Cottage Grove Ave., Dept. 12-A, Chicago, Il. Send me the new book explaining the revolu- tionary radio principle recently discovered; also various Circloid hookups.

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oe SANA INN! Sees MEE That lamp has always needed a new shade and now it’s going to get it! Easy enough with Klein Pliers. A pair of Klein’s isa real worker and a real playmate. You'll enjoy them for making and fixing things all over the house—for your radio and auto, too. They’re thor- ° oughbreds, are Klein Pliers—the re- sult of sixty-seven years of manufac- ture of pliers. Elec- trical and telephone companies all speci- fy them. Pick upa pair when at your hardware dealer’s. Mathias ST & Sons POPULAR SCIENCE MONTHLY October, 1995 Shop Special No.7 > $250 As Illustrated with motor © THE MOST POPULAR MACHINE PARKS EVER BUILT! A winner from the start. A real machine, yet convenient size for the small shop. Does everything in woodworking. Has circular rip and cut-off saw, 6- inch jointer, 16-inch bandsaw. Lathe and shaper attached if desired at small cost. Operates from any light socket. Just plug in and go to work! Write for interesting circular The Parks Ball Bearing Machine Co. 1547 Knowlton St., Cincinnati, Ohio Canadian Factory: 200 Notre Dame East, Montreal, Canada I; peplyperttas Ded MACHINES HII! i | A Revelation in Tone—Volume—Clarity The Kellogg Symphony Re- producer brings the broadcast- ing studio into your very room, so realistic is its reproduction. Piano music, the most diffi- cult to reproduce, sounds so natural that you are completely carried away by its beauty. Vocal selections retain all of the tone colorings of the artist. Orchestra music is indeed a recreation, every instrument can be heard, clear and full. Magnetic diaphragm control —used exclusively in the Kel- logg unit—is the new principle that performs wonders in radio reproduction. _ Compare it with others at a like price and note the differ- ence—$20.00 each. At your dealers—Hear one today. The Kellogg Switchboard & © Supply Company 1066 W. Adams St. Chicago, Ill. nore Worse How to Make a Wooden Press for Pop-Corn Cakes By Charles C. Hall, Captain, U.S. A., Retired OP-CORN bricks that can be eaten without sticking to the hands and giving off countless crumbs, can be made quickly and easily in the wooden press illustrated. The materials required are a board 1 by 5 by 24 in., another 1 by 4 by 24in,, and a third 34 by 414 by 20 in., all of which should be of oak or other hard wood; one piece of wood 1 in. square and 5 in. long, one piece 114 by 2 by 9 in., and two blocks 1 in. thick and 3% in. square, Cut a notch 1\% by 2 in. in one end of the 1 by 5 by 24 in. piece. Meas- ure back from the The crisp, delicious pop-corn bricks that children love so well _ can be made quickly 4 in this simple 4 wooden press same end 8% in. and bore a 1 in. hole. Taper off the other end for a handle. In one end of the other 24-in. piece cut a similar notch. Measure 8 in. from the same end and cut a square cornered hole 14% by 1% in. At the other end form a handle. From the 20-in. long board cut 4 pieces 5 in. long and after drilling holes, screw them together to form a box 5 in. square. Fasten this on the 1 by 5 in. piece previously prepared so that the hole is exactly in the center of the box. Make a square cornered hole 14 by 11% in. in the center of one of the 33-in. blocks and bore a 1-in. hole in the center of the other. One is the plunger and the other is the ejector block. Bore 3%-in. holes at each end of the 1% by 2 by 9 in. piece and corresponding holes in the ends of the handle pieces, so that they can be fastened together with 3,-In. bolts or iron pins as shown. Insert one end of the 1 by 1 by 5 m. piece in the hole or mortise in the upper handle piece and bolt or pin it in place. (Continued on page 110)

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> eaten ds and can be wooden oard 1 24 in, , all of ar hard are and in., and square, a notch oy 2 in. ne end e 1 by. r 24 in. ». Meas- back m the 1 1 Yin. 1d for a piece cut from the cornered ther end t 4 pieces les, screw n. square. in. piece ie hole is e 1% by he 334-in. the center inger and of the 1% ding holes s, so that vith 3-in. 1 by 5 in. the upper t in place. October, 1925 POPULAR SCIENCE MONTHLY —— Hi Corp., St. Louis, Mo. Leading set builders have scien- tific laboratory apparatus to test, compare and prove the facts about transformers. They continue to use more Thordarsons than all competitive transformers com- bined. Doesn’t this answer the amplification question? Daily we hear from fans who paid high prices for musically named, fancy-looking transform- Standard on the m Colin B. Kennedy says: ‘‘We are cranks on audio-frequency transformers and our engineers are constantly running comparative tests on them. The fact that we continue to use Thordarson’s exclusively, in ever increasing numbers, simply means that we believe that it is the best available at this time.”’ Unconditionally Guaranteed ORDARS ena Picmmsssiine majority of quality sets —from a letter dated May 29, 1925, written by Mr. Colin B. Kennedy, President of Colin B. Kennedy Tollow the Lead he Leaders! Build or 4 with Thordarsons ers only to discover that their old_ standbys—Thordarsons— were the real musical instruments. For the benefit of others we there- fore repeat “‘when better trans- formers can be bought they will be Thordarsons.” Few, if any, transformers actually cost as much to make as Thordarsons. Why, then, pay more? ‘Any store can supply you. If dealer is sold out, order from us. TYPES AND PRICES Thordarson Super Audio Frequency Transformers, sub- panel or top mounting types: 2: 1, $5; 34:1, $4; 6:1, $4,50, Thordarson Power Amplifying Trans- formers give best results when pre- ceded by two stages using 314:1 Thor- darson A. F. Trans- formers. Pair $13. Super-Het Builders! For the ‘Best’ 45,000 Cycle “Radio” and other leading authorities recom- mend in highest terms the Thor- darson 2:1 Ratio Transformers. Super-Heterodyne Take no others. © Write for amplification. The Thordarson INTERSTAGE Power Amplifying Transformer, Pro- vides two stages of POWER amplifica- tion when inserted in circuit between Input and Output Power Amplifying transformers. Four tubes are required, but the quality of the reception more than repays you. Only Thordarson builds a transform- er of this type. Each $8. Thordarson Au- toformers amplify clearly the lowest notes of any instru- ment as_ perfectly as the highest notes, They amplify with even magnitude all notes within range of the human ear, A new idea devel- oped and perfected by Thordarson. Write for the Auto- former Hookup Bulletin. Auto- formers are $5 each. latest Thordarson bulletins on Thordarson dealers everywhere, q ii SUB-PANEL MOUNTING TYPE THORDARSONS NOW ON SALE They permit a neater assembly, the shortening of leads and the concealing of wiring—as in factory built sets. Same ratios—same prices—as standard type Thordarsons. If dealer cannot supply, order rom us. THORDARSON ELECTRIC MANUFACTURING CO. Transtormer Cea since I IVE TRAN SFORMER MAKERS ‘WORLDS OLDEST AND LARGEST EXCL Chicago, U. S.A. FS] This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

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St racy and performance as they are in price. Prices Quick Change Gear Lathes 288.00 16"x8’ ‘ 366.00 18"x10’ ‘ Tat | 6* 13"x6’ * 9"x3’ Lathe $241.00 15"x7’ Lathe $447.00 498.00 721.00 @ Easy Payments if desired. Write for Catalog No. 84 South Bend Lathe Works, Sout’ Seno, inp. POPULAR SCIENCE MONTHLY Built on the "SOUTH BEND = a andardized Production Plan. South Bend Lathes are modern Lathes—built in quantities and brought down in prices by modern manufacturing methods. They are as outstanding in quality, accu- [ae SING dé? hlome Worlkssingn buys any WITTE EN- GINE up to 10 H. P. Uses Kerosene, Gasoline, Distillate or Gas. Equip- ped with celebrated Troubleproof WICO Magneto. Simplest and cheapest to operate. New device makes pena sae os Dt ane ower. Sizes 2 to 25 . P.—all styles. ohne ll TR ENGINE BOOK Write today for my new illustrated engine book—sent absolutely Free. No obligation to you. ITTE ENGINE WORKS 2228 Witte Building, - - - KANSAS CITY, MO. 2228 Empire Building, - - - PITTSBURGH, PA. That Extra Pair of Hands ET a Luther Vise be that “extra pair of hands” you always wish you had when you tackle a mean “fixing” job— whether it’s taking apart a spark plug, loosening a rusted-on nut, or filing down a metal part of some kind. This sturdy, tight-holding vise has a wider jaw spread and a larger feed screw than any other vise of equal size, and has an extra-strong panelled slide bar. Aclean-built, husky work-pal that never goes back on you — saves you many a skinned knuckle and makes any number of little jobs easier. Four sizes—jaw spreads of 1/2", 2", 212" and 3". Sold by most good hardware stores. etates rear threes “Tet LUTHER GRINDER MFG. COMPANY Department A ilwaukee, Wis. Also Manufacturers of Luther Tool Grinde-s Nothing less than 21 Ruby and Sapphire jewels is good {5% enough for the BURLING- \yg TON masterpiece, fe Quality and Style Adjusted to second—tem- perature — isochronism — eee en goldstrata case, in 100 designs. Un- surpassed qual; oF rock- ttom prices. $1 $ awn * si) =. yy own \Y Ie ‘ down © : | Gl brings your choice. Balance in small monthly sums. Send for FREE Book Write today for FREE Burlington Watch Book. Find out about this big special offer made fora limited time! Burlington Watch Company 9th Street and Marshall Bivd. Dept. 13-67 Chicago, Ullinois a ll ‘West of Rockies , $26.50 In Canada, $35 The SAAI off SPEAKER Volume with tone quality You need no longer object to loud speakers because of their harshness. Hear the Saal at your dealer’s today. It combines volume with a velvet tone. It’s built to last a lifetime. H.G. SAAL COMPANY 1800 Montrose Avenue - Chicago 25 Press for Pop-Corn Cakes (Continued from page 108) Fasten the other end similarly in the hole in the plunger block, using an iron pin, Fasten a 5-in. length of broom handle to the ejector block and let it projegt through the bottom of the box. To make about 18 bricks, pop 8 qts, of corn. Take 2 cups of molasses, 4% cup sugar, and 1 tablespoon of vinegar, and cook until the syrup hardens in water byt is not brittle. If dark molasses is used, it is well to add 14 teaspoon of soda to improve the color. Pour the syrup over the corn in a large vessel and stir. Grease the square box with butter, il] it with sufficient corn to make a brick and press the handles together. Then push How the pop-corn candy machine is put together HOLE 1'k12 HANDLES fF PLUNGER OR PRESSER BLOCK 1k39%3x3%" OAK Sa x3lax5" INSIDE ql EJECTOR BLOCK DIA. 5"LONG SCREW BOX TO BOTTOM HANDLE up the broomstick connected with the ejector block and remove the brick witha slight twist. The resulting brick, which will be about 1 in. thick and 3% in. square, should be wrapped in waxed paper. How to Repair Leak in a Copper Ball Float THE COPPER ball float used in a bath- room flush tank sometimes springs a leak and fills with water. As it is diffi- cult to find the leak by ordinary methods, punch a small hole in the float and blow into it hard enough to force the water out of the leaking hole. When the water has been removed in this way, it is a simple matter to solder both holes.— C. W. HUBERTZ. Making Christmas Presents OUR home workshop never is more useful than when you are preparing for Christmas. It is not too soon to start work on the gifts you plan to make. You will find many sugges- tions in this issue and many more in the November and December numbers. There will be articles on toys, games, furniture of various kinds, jewel boxes, radio cabinets, kitchen equipment, | greeting-cards, and novelties.

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the hole on. pin, 1 handle - Project 8 ats. of , % cup gar, and rater but is used, soda to rup Over . utter, fill rick and 1en push \NDLES 3Y2x5" DE »X TO HANDLE with the ick witha ck, which 1 3% in. in waxed ina 1 a bath- springs a it is diffi- ordinary 1 the float » force the When the way, it is 1 holes.— jeeaeenssecceses: ee esents ever is you are ; not too you plan ’ sugges- re in the 1umbers. , games, el boxes, 1ipment, October, 1925 POPULAR SCIENCE MONTHLY They said j it patie be done: FR But now --- Complete with built-in loud speaker of great volume and superb tone quality. Encased im - « - As fine a heavy genuine solid mahogany cabinet as ever graced any radio set. At sixty dollars - - - Not only complete with built-in loud speaker and mas- sive mahogany cabinet, but this wonder circuit has been scientifically perfected and each and every single part strengthened and co-ordinated. For example - - - The new Freshman Masterpiece straightline wave length condenser with vernier attachment which assures hair- line selectivity—permitting you to tune in thestation you want without interference over the entire wave length range. This is merely one exclusive feature of . this New and Improved Freshman Masterpiece Receiver For sale at AUTHORIZED FRESHMAN dealers only Chas.Freshman (Qe, Inc. "RadiolReceivers andre Parts FRESHMAN BUILDING 240-248 West 40TH ST~NEW YORK.NY. Magumasmuneceais Act OFFICE —— 327 S.LA SALLE ST New and MAN RESHMAN © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS, See page 6. 111 ASTERPI ECE Price 10% higher West of Denver

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Sere ea eee The New Millers Falls ; No. 77 is a great deal fy of hand drill for a 7 small sum of money. It is a good tool— regular Millers Falls standard. Ask your hardware man to _ Readthese show it to you—and specifications Chuck—3 jaw- COMpare the tool improved pro- tected eprings, pon ai ie to} round s heat drills. Cut gears; steel pinion. Malleable iron frame. Solid end handle and side itself with its amaz- ingly low price. One of a complete line; no matter what your handle, stained ° : hard peed: work, there is a Mil- Length 213" lers Falls Hand drill llbéo:. tO Suit you. MILLERS FALLS COMPANY | Millers Falls, Mass. 28 Warren Street 9 So. Clinton Street New York Chicago Manufacturers of Mechanics’ Tools, Hack Saws and Automobile Tools MILLERS FALLS TOOLS 4 © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. | POPULAR SCIENCE MONTHLY October, 1935 Toy ene Air-Liner Made with Pocket-Knife TILL longer than the aerial express cruiser described last month, but of a radically different design, is this toy model S of an air-liner. It is of a type that some day may be used for crossing the Atlantic. Like the other toys in the present series, of which this is the fifth, the model is made from odds and ends of wood and tin. Most of the work may be done with a pocket-knife. Except for the tail members and the propellers of the two motors, the parts are wood. The three wings, which are 3/16 by 134 by 12 in., are nailed to the body. RED r2k2ry || iE | 1D \ {\ YI. Hi | SOLID WOOD, ad f° ae rot . | Tt li 7 24 x6) Nt S| MOTOR |} | DOORS fens r | CHORD \ AND A ied LENGTH what at ni t . HEIGHT lt om k ' na FE COLOR Laces HULL WHI! Us AND RED WING WHI ty, LOWER —~ PONTOON WING 4x4" Wx Side, top, and front views of the air-liner and suggestion for attaching lower wings The lower wing, which is made in two halves, each 4 by 1% by 4 in., can be fastened to the hull in any convenient way. Perhaps the simplest is to use small metal angle brackets above and below each wing or to nail a flat piece of | tin to the inside end of the wing and then attach the metal to the hull, as illustrated. The other details of construction are made clear in the drawing and, of course, can be modified or altered in any way desired. The next and last article in the series, which will appear next month, will describe a small plane, or “air flivver.”,—DONALD W.* CLARK. Simple Joint for Drawers HILE dove- tail joints are best for fitting the sides to the front of a drawer, they are hard to make, and ama- teurs usually fight shy of them. The joint illustrated is made much more easily. The side is set into a rabbet in the front, glued, and held with a couple of brads. Then holes are bored through the side into the front to take dowels, the number and size depending upon the dimensions of the drawer. Dowels of the same kind of wood as the drawer are made with the aid of a dowel plate and are glued in the holes, cut off, and smoothed.—H. C. WHEN you wish to mend or repair any risk You would not sew a silk dress with cotton. with an inferior glue? LePage’s the pairs. ard for 40 years. E LEPAGES will _ | it eae MANUFACTURES att RUSSIAC —! — a aeCeareee article of useful value, do not using a cheap or inferior glue. Why mend a broken article The cost of is nothing compared to saving of making permanent re- Use LePage’s Glue, the stand- Insist on LePage’s. Ne} 4 GLUE 2Gsh Lasts Indefinitely—Pays for Itself meenemy et a * sae ie aha 1 inst acid and leakage. ze plates. Order yours tod: SEND NO MONEY order is received. xtra aa cash with ¢ a seder. “Mail isi ote oer ier now COMPANY r TTERY 1219 So. , Wabash Ax Ave. 7 Fea ne “Chicago, Uh Prices: 6-volt, 190 Amp. $1 255 1g0.Am 4ison 27 140 Amp. bth World: | STORAGE alte! ES RADIO 6999 y ee “B” Battery © and performance unheard of before. Rec gible cost. Approved and listed as Stand: Stat randards, Halo News {ab Pt af fax "ae ae an other im ipped with » old Rubber Case, an insure ‘Extra heavy glass jars. “Heavy, Just state number of batteries wanted and we wi Offer: 4 patteries in series ( (96 volts), an tteries. 6 discount ce, Pon : Sse seo —Easy with the ¢ OTTAWA Log Saw! Wood ong for $3 acord brings owner $45 a day. Use easy to move. Saws faster than 10 men. Shi for 1801-T Wood Street P. Engine for other work. Wheel moun‘ rom factory ornearest of 10Branch houses. a FREE Book—‘‘Wood nee eee a he sg OTTAWA MANUFACTURING CO. Ottawa, Kansas Room 1801-T Magee Bidg., Pittsburg, Pa, GEARS All Kinds-Small ost ecotmnte made ond a prions reasonable, e carry 8 line of gears in stock weed imme shipment. Can also p= ky of all kinds, fi hy us your in- Write for Catalogue 214 CHICAGO STOCK GEAR WORKS 105 South Jefferson Street Chi :

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ber, 1925 dl repair > not glue. 3 with article ost of xd to nt re- stand- Page’s. NY hicago, Ill 8 | Arm. $1.00, Ae Lr a ea Dials at 210 e new 1000 rage Battery C, Chicago. ouncements. ee rere ond us your i logue 214 SEAR WORKS treet 1 EA gerober, 1925 Tuned Radio Frequency Kit $12.00 Complete with Brackets The complete Low Loss Inductance System, comprising two tuned circuit POPULAR SCIENCE MONTHLY 113 NOW-AII the world _ transformers and an antennae coupler with a uniquely constructed variable primary for governing the selectivity of the antennae circuit. can have it! The sensational favor which Chicago and New York showered upon the AERO COIL has prompted its designers to make it available to every fan in the Nation. Vigorous plans are, therefore, under way to place the Aero Coil where every city and village can see it and witness its markedly superior performance. Courtesy Popular Radio = e Acclaimed by Chicago and New York for its greater SELECTIVITY, POWER and SENSITIVITY! Enjoy the ‘‘knife-edge’’ selectivity with which Aero Coils cut through the tangled mass of Chicago and New York broad- casting at will! Enjoy the uncanny sensitivity with which sets built of Aero Coils pick up the far off, small, low-wattage stations that you never thought existed! Be thrilled by the amazing volume with which Aero Coils amplify for the loud speaker, reception which you have always had to listen to on the head phones! Build a 5-Tube Tuned Radio Frequency Set with Aero Coils .... . the true low loss inductance system. PATENTS PROTECT ITS SUPER-EFFICIENCY Its Jower circuit resist- ance, its lower high fre- quency resistance, its lower distributed capac- ity, and the fact that its dielectric is 95% air are the reasons why the Aero Coil tunes so sharply into resonance—and why actually uses the energy which other types of in- ductances waste. Hence, Aero Coil is the induct- ance of today—and to- morrow, and you can be 9 SF, Air dielectric 0 — No dope on windings — All turns air-spaced—Solonoid (cylindrical) windings —Variable primary Engineers recog- nize_ cylindrical winding to be su- it perior to any other. The Aero Coil is the only Air dielec- tric cylindrical in- ductance with a variable primary. Aero Coil patents prevent imitation. assured that it is—for the construction which makes it the ideal inductance is patented, and no induc- tance can be made like Aero Coil un- less in violation of these patents! Build Your Set Now! The construction which makes possible the far su- perior results obtained from Aero Coils alsomakes them cost a bit more— but, performance consid- ered, their price is low. $12.00 for a set of three, complete with nickel plated mounting brackets which fit any condenser. Go to your dealer’s today and obtain a set of three. Acircular containing com- plete hookups for building a more se- lective, more sensitive, more powerful five-tube receiver is enclosed in each package. If your dealer has not yet obtained his stock of Aero Coils, order direct, enclosing price with your order. Free Booklet showing new circuits and giving full constructional informa- tion of help to any fan or set Write for the Aero Booklet. ilder — mailed on request. © AERO PRODUCTS, Inc. 217 North Desplaines Street, Chicago, Illinois Pacific Coast Representative Successors to HENNINGER RADIO MEG. CO. t S. A. WINSOR, 1221 W. 16th St., Los Angeles ERD co| All Aero Coils embrace a patent-protected method ofconstruction which makes possible a far more efficient inductance performance than is possible with other types of coils, © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. Use AERO COILS Wherever An Inductance Is Requited THE ONLY AIR DIELECTRIC COILS HAVING VARIABLE PRIMARIES IN ANTENNAE CIRCUITS The Aero Coil 3-Circuit Tuner Another adapta- tion of the pat- ented protected Aero-Coilconstruc- tion and for that reason a marvel- ously efficient three-circuit tuner. More than covers the broadcast wave bandwhen shunted with a good .0005 condenser. This is : 4 the tuner which in set brought in Havana, Cuba, in the daytime in ral Price. ...»+ $8.00 The Aero Coil Radio Frequency - Regenerative Kit Consists or one AERO COIL 3- Circuit Tuner and one AERO COIL Antennae Coupling Transformer. Makes a morepow- erful, more selec- tive 4-tube, non- radiating set. Price..... $11.00 The Aero Coil Wave Trap Unit Also for Crystal Sets By reason of the characteristics made possible by the Aero Coil construc- P tion, this unit makes a very efficient ed wave trap or crystal set. Price $4.00 The Aero Coil Oscillator for Super Heterodynes The characteristics achieved through the use of the Aero Coil principle make of this instrument the ready means to tremendously in- crease the efficiency of the oscillator circuit in any Su- per Heterodyne receiver. Pr. $5.50 Prepared by KIRTLAND-ENGEL ADVERTISING COMPANY - CHICAGO

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Norwich, How to Pick a Hammer OU’RE proud of your per- sonal kit of tools. Every “regular fellow” is. And so it pays to be especially particular when selecting the tool that’s most in evidence because most used —your hammer. Before you buy a hammer bal- ance it in your hand; heft it; swing it. Has it a “hang” that makes you itch to come down on a nail and drive it home? Is the head press-forged, not drop- forged? Has each end of the head a special temper to best fit it for the work it is intended todo? And the handle, is it of clear hickory, free from knots or blemishes, and not stained to cover up imperfections? And is it put on for good? There’s only one hammer that answers “‘yes’’ to all these ques- tions. But it’s easy to identity. The name “‘D. Maydole’’ is stamp- ed on the head. Be sure it’s there before you buy. Your dealer sells and recommends the genuine Maydole Hammer. Ask him to show you the size and style you want. Have you a copy of our interesting Handbook and Catalog No. 23 “‘B’”’? If not, send us your name and ad- dress. THE DAVID MAYDOLE HAMMER CO. New York POPULAR SCIENCE MONTHLY October, 195 Winners in Profitable Home Workshop Job Contest HAT the average home workshop is worth in dollars and cents— the money that is saved or earned through it—-was demonstrated more vividly and impressively than ever before in the contest for POPULAR SCIENCE MONTHLY’S readers on “‘My Most Profit- able Home Workshop Job.”’ The re- sponse was exceptional both in the number of letters received and their | generally high standard of excellence. The winners are as follows: First Prize, $25, Theodore F. Geltz, Massillon, Ohio Second Prize, son, Dayton, Ohio Third Prize, $5, P. A. Whear, Rock Island, Tex. Ten Prizes, $1 each: Gordon Holford, Gladstone, N. M.; J. E. Swanger, Santa Ana, Calif.; A. F. Duncan, New West- $10, R. L. Hankin- First-prize winner installed a heating plant minster, B. C., Canada; John Mitchell, Point Pleasant, N. J.; Edward B. Smith, Mullen, Tex.; Kelley Lewis, Longmont, Colo.; Harry P. Botsford, Portland, Oreg.; H. Caldwell, Toronto, Ont., Canada; D. H. Frew, Lisbon, Ohio, and M. L. Brooks, Tonkawa, Okla. Honorable Mention: J. G. Pratt, Washington, D. C.; Russell E. Oakes, Waukesha, Wis.; B. E. Foster, Lake- wood, Ohio; F. A. Coffill, Hantsport, N. S., Canada; L. M. Evans, Haigler, Nebr.; James G. Walsh, Dunmore, Pa.; J. S. Daver, Bombay, India; J. H. Dorn, Dresden, Ohio; H. D. Smith, Nyack, N. Y.; Mrs. J. M. Drane, Louisville, Ky.; David B. Hendrix, Byington, Tenn.; Alex C. Fabris, San Antonio, Tex., and E. F. Matheson, Utica, N. Y. The first, second, and third prize- winning letters follow. Installing a Heating Plant By THEODORE F. GELTZ Massillon, Ohio First Prize O ECONOMIZE when building 10 years ago, we chose a hot-air heater, but soon learned that a change was desirable. Four years ago an opportunity (Continued on page 116) ie ee, P RACTICAL Books THAT WILL RAISE YOUR Pay RITTEN in easy-to-understand non-technical language these books will help you in your chogen trade. Every book is an entire course of instruction condensed into one volume. Thousands of men haye used them to increase their pay, You will find them full of informa. tion and ideas that will help yoy raise your pay. Painting and Decorating Ross Crane Book of Home Furnishing and Decoration............-...Cloth Baas House Painting Methods with the Brush and Spray Gun, by Vanderwalker, eee: Interior Wall Decoration, by Vanaer- walker..............Leatherette $4.00 The Mixing of Colors and Paints, by VANGCTV AKER a. 555.0 4 .0(0:0.0:8 Cloth $2.00 A Show at Sho Cards........ Cloth $4.00 Sign Painting, by Atkinson...Cloth $4.00 Strong's Book of Designs PSO AU RTBU 5 .o ass ou eae or $4.00 Modern Painter’s Cyclopedia Cloth $2.00 Automobile Painting.........Cloth $1.50 New Hardwood Finishing.....Cloth $1.50 Steam Engineering Swingle’s Handbook for Steam Engineers and Electricians. Leatherette $4.00 Examination Questions and Answers for Marine and_ Stationary Engineers, LS eS: Se eee eer $2.00 Steam Boilets......... Leatherette $2.00 Swingle’s Catechism of Steam, Gas and Electrical Engineering. Leatherette $1.50 Carpentry Books Cloth Binding Modern Carpentry, 2 vols......... $3.00 The Steel Square, 2 vols........... $3.00 Modern Estimator................ $1.50 MAIO BOT PPAUIING ooo cs a5. 62s 00 516 $2.00 Builder’s Architectural Drawing.... $2.00 COTES Se ern Practical Bungalows.............. $1.00 Roof Framing, by Van Gasbeek.... $1.50 Electrical Books Telephony, Including Automatic Switching, by Smith. 450 pp. Leatherette $2.50 Practical Applied Electricity....... $2.00 Wiring Diagrams and Descriptions $1.50 Armature and Magnet Winding.... $1.50 Electric Motors, D. & A CHECK —the books you want and mail today with your remittance. We-will send you the books you order on our guarantee that if you are not thoroughly satisfied with them we will re- turn your money. PopuLAR SCIENCE MONTHLY 250 Fourth Avenue New York POPULAR SCIENCE MONTHLY Gentlemen: Please send me the books I have checked for which I enclose my remittance of $.... a ordering these books on the basis that if I am not satisfied my money will be refunded. IS] This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

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ig gineers $4.00 ers for pineers, $2.00 as and $1.50 $ PARP AAAR oo eer ee rere cece Ssssssss 1d mail ce. you order 1 are not ve will re- October, 1925 POPULAR SCIENCE MONTHLY 115 UTAH ine SPEAKS ITSELF The guaranteed loud speaker Utah’s supreme loud speaker. We say it to be the best manufactured in the United States today. Ask the man who has one. We are manufacturers—not assemblers. Make the Utah booth your headquarters while at the World's Fair Radio Show, New York, Sept. 15-19 and in Chicago at Fourth Annual Exposition Nov. 17-22. THE UTAH SUPER-FLEX. The Super- Flex has a tone chamber equal to that of the usual horn type. Stands but 8% inches high by 6 wide. Finished in a harmonious brown. Weight 3 pounds. Price $14.00 Horn is finished in rich semi- dull black Morocco leather finish, 14-inch bell. Weight 1% pounds. Price $25.00 THE UTAH PHONOSPEAKER. Handsomely finished in black rubber. Furnished with stand to rest on turntable of talking machine, or without. THE UTAH SUPREME. Finished in a_ soft antique mahogany, designed to please th eye and ear. Measures 1014 x 8 x 7%. Weight 8 pounds. Price $25.00 Price with Stand $10.00 Without Stand $9.50 UTAH RADIO PRODUCTS COMPANY Dept. 516 1427 S. Michigan Avenue Chicago, Illinois © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

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SPEEDY SERVICE SPLENDID VALUES Ask Our Customers -there are many in Your Community Outer and Inner Clothing and Shoes for All the Family~Dry Goods~Rugs~Jewelry~Furniture Auto Supplies-Sporting Goods and Radio Supplies-Paints-Hardware Stoves~Furnaces~Farming Tools — — — Many of our Orders are Shipped the Same Day we Receive them -8 Hour Service-and practically all of the balance on the following day ~ 24 Hour Service Charles William Stores ‘The Long Established Mail Order Merchants of — ™* New York City 518 Page Handy Catalog sent free on request to'385:Srores Building SAVED on all Standard Typewriters

AtLast= World’s best typewriters with every modern writing feature at positively lowest prices and on easiest terms ever offered. A Year to Pay 5 Years Guarantee Standard Machines so perfectly Re- Manufactured by the exclusive Young Process that they look and write like brand new. Our exclu- sive, distinctive process makes possible better typewriters at lower prices. eR BIG ILLUSTRATED <} Young Typewriter Company POPULAR SCIENCE MONTHLY

654 West Randolph Dept, 142.A. . (Chicago, ti.

BARGAINS! ~ SAVE: TO't/ | WRITE FOR CATALOG | RANDOLPH RADIO CORP. 159 N. UNION AV. Dept. 3 CHICAGO, ILL.

Getting Ahead? Read the advertisements on Pages 146 to 174 this issue if you want to get ahead!

milion Worsahop Profitable Job Contest (Continued from page 114)

was afforded for purchasing a new 23-in., seven-secftion round steam boiler and 9 radiators. These were installed after the hot-air furnace had been: sold. The problem was to heat a garage and a seven-room house with 2 hallway too narrow to receive a radiator. Hall and living-room had adjacent cold-air regis- ters. To heat the hall and open stair- way, aradiator was hung beneath the hall register and incased, receiving cold air through the living-room register and wall and emitting hot air in the hallway. LIVING ff HALL DINING ROOM

HOT AIR

COOL AIR

Steam radiator suspended below an old hot- air register to warm a very narrow hallway I rented a set of pipe-cutting tools and bolted the vise to a post in the basement where all the pipe was cut, and threaded. Nine registers were set, single-line connected, and a pipe radiator was assembled for the garage. An electric thermostat with an eight-day clock and a motor were added and connected with the lighting line, the clock serving also as a dining-room timepiece. A conservative estimate of the total cost of the system, excluding labor and deducting the $80 for the furnace and pipe sold, and allowing for old mate- rial, shows approximately $500 saved. I am now 66 years old and never learned or worked at a mechanical trade, my own being coal-mining. For many years, however, my occupation has been bookkeeping. The installation of this system was accomplished alone, except that my wife shifted blocks while twolarge radiators were moved up the stairway. Mahogany Bed and Desk By R. L. HANKINSON Dayton, Ohio Second Prize

OULD I do it?

The president of our company, my wife, said I could, and with this encouragement I decided to try. The time of this incident was immedi- ately following the World War when the (Continued on page 118)

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS, See page 6.

October, 1925

Your Own Shirts FREE Here is an amazing easy way for you to make $5 to $10 every evening after work. Our wonderful new shirt line contains the most attractive styles in silk, linen, madras, etc., and can be sold 50% cheaper than store prices, We will furnish you a free sample line and tell you exactly what to do to make big money this way. We tell you exactly what to say. You receive your profits in advance—we de. liver and collect. Write at oncefor free territory offer. No obligation. But act quick. Address Charles Hope, FASHION WEAR SHIRT CO, 1200-20 Jackson St., Dept. M-171 Cincinnati, Ohio

W. H. Adams, Day- c= ton, Ohio writes: V. A. Marini, Santa Cruz Cal. (Nov. 1924) reports $11,275 sales in 3 months Alexander, of Penn., $3000

« (Aus.1925) ° . 2 only things T e bought that equaled advertisement.” Patillo, Ocala, writes: “Cris po all you claim.” Kel-ij » $700 ahead in 2 weeks.

wr NON WE START YOU IN BUSINESS! Furnish secret formulas, raw material, and equip- ment. Small capital required; no experience needed. Build Business of YourOwn Nolimit to the sale of Crispettes. Everybody likes them. It’s a delicious food confection made with or without sugar. Write for facts about a business that will make you independent. Start in your town. Profit $1000 Month Easily Possible Send postal for illustrated book offacts Itcontains enthusiastic letters from others—shows their places of business, tells how_and when to start, and information needed. Free. Write now! Long-Eakins Co. 1047 High St. Springfield, 0. Agentssv"s5; New SELLING SENSATION Take orders for famous Stay-Prest Trousef Presser. Puts perfect crease in pants—takes out wrinkles and baggy knees. Sells quick to men and housewives. Newest thing out. Big repeater FREE Sezzinc Ourrit Profits in advance. Ames made $24 in 4 holirs Randle sold 33 first day. Special Offer gives you Selling Outfit aheolutely FREE. ‘e gual 1 you will make sales. rite for plan and exclu- sive territory. Act.auick. Get Free Outfit. he Getgey-lung Co. R143G. Bldg.

Page 107

lf Up EASY TIME (EY Get FREE pctober, 1925 POPULAR SCIENCE MONTHLY 117 Thorola Loud Speakers with ‘'Thorola Low-Loss Doughnut new burnished Bakelite horn Coils installed in yous present and gold throat-band are even set will give you mapy of the better in appearance and per- greatest Thorola advautages. formance. Thorola 4........ $25 Complete set (3) $12 Thorola Jr. .....$15 Per coil..............84 ay for you ning after shirt line styles in — ANNOUNCEMEN' mple in ptm tan abinets sugges! Cc nte: ic- . ho eae This is of interest to opera-goers, to lecture and sym- om : In smart Thorocco Cabinet $ tell you phony patrons as well as to the dancing set, and to the S-tube Thorola Tslodyne is 89 coma those scientifically interested. agate gy rey ee territory Artistic radio has come with Thorola Islodyne, em- ieiaiieaieias HIRT CO. bodying the Isolated Power principle made possible innati, Ohio only by Thorola Low-Loss Doughnut Coils. They conquer ‘‘pick-up” of unwanted stations, waste of | power, uncontrollable “oscillation,”’ freak wiring, un- certain operation. Radio experimenters know what all this means. Radio listeners no longer need to know! With Islodyne action any one station wanted is cleanly selected, even in broadcasting centers. Utmost power is isolated — focused — on this one set of signals only. The delicate radio impulses do not conflict, neutralize, offset each other. Full tone, unmodified—full volume, full distance at last are possible, at all wave lengths. With temperamental factors banished, Thorola Islo- dyne achieves uniform reception. The same stations keep coming in the same. The set your dealer dem- onstrates tells what your set will do. Radio reception is unmistakably elevated. There is a complete Thorola receiver leading its field by far, just A ig INESS! as Thorola excels in loud speakers and apparatus. and equi . nce needed. The Thorola name is surety of radio development not Own to be eclipsed. The intense interest in the 5-tube lade with ot Thorola Islodyne at every radio store will tell you usiness that oe ° your town. where expert opinion centers today. Go and listen. ossible Tt contains REICHMANN COMPANY, CHICAGO rt, and al afield, 0. ISATION Prest Trouser ints—takes out quick to men t. Big repeater y $24 in 4 holirs. ng gives you e guarantee lan and exclus Free Outfit. | & This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS, See page 6.’

Page 108

AIS APT NA! SAPD TP UT IS MER ER ERS! Fn Vs OE Tae EL POPULAR SCIENCE MONTHLY October, 1925, Gauging the Good in New Machines Can you see the good in new machines and show up their possibilities? Can you gauge what they're good for, pro- duction-wise ? Veeder Counters rate ma- chines by the actual figures on production-rate. Here’s your proof of work- capacity, and pointer to greater capacity. Each new step toward a better machine counts for what it’s worth on your COUNTER The small Revolution Counter be- low registers one for a revolution ofashaft,recording a machine operation or product. Though small, this counter is very durable; its mechanism will stand a very high rate of speed, making it especially — suit- able for light, fast-running ma- | chines and most adaptable to ex- perimental work. If run backward ; the counter sub- tracts. Price $2.00. (Cut 4-5 size.) Small Rotary Ratchet Counter, to register reciprocating movements of small machines, also $2.00. Here’s the handiest instrument for finding revolutions-per-minute of a shaft or flywheel. You hold the tip of the counter against end of revolving shaft; press lightly when the second hand of your watch comes to O; release pressure when minute is up. A spring clutch controls the recording mechanism. (Cut less than }% size) The Veeder Speed Counter enables you to keep motors, engines, generators, line shafting and machines operating at efficient speeds. Price, with two rubber tips, (as illustrated) $3.50. FREE: The 80-page Veeder booklet of Counters, to help in your development-work. The Veeder Mfg.Co. 4A Sargeant St., Hartford, Conn. Profitable Job Contest (Continued from page 116) price of furniture was at its peak. The need for action arose when my wife desired some new furniture for her guestroom. With an order for a mahogany bed on my book, I started my furniture factory in the basement of ourhome. My equip- ment comprised a workbench and a few hand tools. The plans consisted of an illustration cut from an advertisement. I went to a dealer in second-hand building material and secured enough mahogany to make the bed. Some of it was so black and dirty it was scarcely recognizable. The cost of the lumber, cut to rough dimensions and delivered at my home, was $1.75. The cost of stain and varnish made the total cost of ma- terial for the bed approximately $3.50. The scrollwork was done on a small jig- saw, which I had owned since boyhood. The spinet desk to match the bed, I considered a more difficult job, and for this reason I made a full-sized layout on paper. I purchased new mahogany for it at a cost of $6.50. Other extras cost about $1. Qn figuring up the results, I found that I had converted material costing approximately $11 into furniture that, if purchased, would have cost at least $125. Enameled Kitchen Cabinet By P. A. WHEAR Rock Island, Tex. Third Prize Vy ate carpentry is not my line of business, I take great pleasure in making different pieces of furniture for the home in what spare time I can find. So the department that interests me Home Workshop Blueprint No. 5 was used by P. A. Whear in making this kitchen cabinet most in your monthly is the Home Work- shop. I have made quite a few pieces (Continued on page 120) © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. An Easily Made Smoking Cabinet VERY man who works with toolb— whether he isa novice ora ““‘handy- man” with long experience—will find it easy to build this handsome smoking cabinet. _ Space for cigars, cigarettes, match boxes, cigar and cigarette holders and pipe cleaners are provided. A feature that every smoker— and his wife—will appreciate is the ash trays (which are removable) at both ends of the cabinet. When not in use these ash receptacles can be closed. Blueprint, including full details for making this handsome smoking cabinet, can be secured by sending 25c to— Popular Science Monthly 250 Fourth Ave. New York SALESMEN-You new» Haye Wished for This Thousand Times No wonder 99 men out of 100 say we have thecreatest proposition ever; Our startling new selling plan isa “*knockout’’---it’s different. Our 3 high-class specialties sell to every single man over 18 years of age whether he is digging ditches or run ning banks, They are new. Guaranteed: -Our men often riake $5.00 profit in a Greatest Offer single hour. Many make $50 in a day. Ever Made to er 50 per cent profit on every sale Salesmen! besides we deliver and collect. Sales re- peat automatically. No experience. Get S268 £0 satire bones FREE. full details of our amazing sales plan month. Many make| and our friend-making products. Earn big $50 to $500 month, money. Write today. spare or full time. ; RHODES MANUFACTURING CO., Inc. ee ae P-240 Pendleton & Cozens, St. Louis, Mo. SPORT BODIES $ ie) For Ford or Cheviolet We cam furmsh you with the latest style roadster or racing body at ices that will i FORO RACER Dept. Louisvitte 2 KENTUCKY SUPPLY CO. 159 N: UNION‘AV: Dep Real Estate Educatod This book gives a most comprehensive yet most concise arrangement of useful facts about buying, selling, leasing and sub-letting of Real Estate, contracting, for erection or repairs, mortgaging, transferring. insuring, etc. Cloth, 256 es. Price $2.00, postpaid, Popular Science Monthly, 50 Fourth Avenue, New York City.

Page 109

>ber, 1925. naking secured ithly it of 100 say osition ever: g plan is a at. UISVILLE ENTUCKY October, 1925 Ra STRAIGHT LINE FREQUENCY POPULAR SCIENCE MONTHLY - i ee : rs fp, we = Fe Dn ‘ tty ’ t}y ~ fore)! =~ at } | Wide Hida CONVERTER HE modern radio receiver has abundant tone, volume and power—now it may have perfect, simplified control. The Rathbun Straight Line Frequency Converter is adapted for use on your receiver—every receiver—-without change of equipment—except the condenser dials. Each station is given Stations indicated in kilocycles and wave- lengths showing crowding with an ordinary capacity condenser. Stations | Partially separated and _ tuning slightly improved with a Straight Line Wave Length Condenser. a distinct reading at a uniform distance from the next. Real log- ging becomes a fact. The stations are distributed with flawless pre- cision over 360°—one complete revolution of the Dial. There is no limitation or crowding as on controls using only half a dial. Radio control is simplified. The Rathbun Straight Line Fre- quency Converter providesstraight line frequency tuning with or- dinary capacity condensers. It is interchangeable with any dial— on any receiver. It is sold with the guarantee of reliability and satisfaction attached to all Rathbun Radio Apparatus. See and Try it—at Your Dealer’s If your dealer cannot supply you, send Money Order ($3.50 each) and your order will be shipped promptly by Parcel Post prepaid. Rathbun Manufacturing Co., inc. Jamestown New York © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. Practically even separation over half the dial with a Straight Line Frequency Condenser. 4 d j e t Pe-y .~ > % * } e Rp, " ae Pod ” ae %~y e = Ry Way wert 42 205 th we 5 2 '3—j—2998 1000 KcO a ~iig 0 + = Wag % & % SK / \ * é § ¥ % E & & 8B $ *% CJ w £ Fs % Complete and equal separation of stations over the entire dial with the Rathbun Straight Line Frequency Converter.

Page 110

favorite Snap-On Set in garages, factories, power plants and wherever else there is wrench; i.” & Limes Out of 10 —when you go to a garage for re- pairs on your car, the mechanic works on it with genuine Snap-On Wrenches. That gives you an idea of the almost universal preference of these fine tools by expert auto- mobile repairmen. if You Are Particular About Your Car... If you want to keep it running like new for a long, long time, don’t wait for serious trouble. You can buy a little:set of Snap-On Wrenches for a small sum that is designed especially for work on your car alone and it will make it so astonishingly easy for you to keep all the nuts and bolts properly tightened up that you will never let your car get badly out of fix. With your Snap-On Set you can prevent road trouble and save the time and expense of being towed in. Use genuine Snap-Ons like the experts use. Look for the name Snap-On on each handle and socket. It is not a genuine Snap-On without the name. © Snap-on BB LEEDS INTERCHANGEABLE Socket Wrenches SNAP-ON WRENCH CO., MFRS. Milwaukee, Wisconsin

Motor Tool Specialty Co., 14 E. Jackson Bivd., CHICAGO Gentlemen: Please send particulars about Snap-On Set for 5 See ee e........Car. (If interested in Master POPULAR SCIENCE MONTHLY

| shop activities.

Nee Ome Workshop

Profitable Job Contest (Continued from page 118) illustrated initand havesoldsomeofthem. The most profitable one was a kitchen cabinet, built from your Blueprint No. 5. I did not follow your directions exactly, but got the main idea from the blueprint. A cabinet like the one I made costs about $65 to buy; it cost me for material $25.53, so that I figure I saved at least $35 by making the cabinet myself. In addition I made a second cabinet and sold it at $25 profit, making me a profit of $60 on the two cabinets. It took me a month to make the last cabinet, working at it only in the evenings after six o’clock. The tools used were hammer, saw, square, and a large and small plane. The dimensions were 71 by 48 by 26144 in. The cost was as follows: Glass knobs, $1.20; wood screws, 60 cts.; 2 qts. paint, $1.90.; 2 qts. enamel, $2.40; corner braces, 30 cts.; latch, 20 cts.; elbow catch, 6 cts.; sandpaper, 25 cts.; hinges, 46 cts.; blacksmith, 50 cts.; oilcloth, 60 cts.; nails, 25 cts.; express, $1.99; postage, 24 cts.; lumber, $9.50; flourbin, $2.80; glass, 60 cts.; glides, 10 cts.; lock, 25 cts. THE entries in this contest revealed an almost incredible range of home work- The tabulated list of projects ranges all the way from awn- ings, bathtubs and beds, to tea wagons, trellises and wells.

aint = Perch

i! PREVENTING the ‘aauaaen destruction of pigeons by rats, the perch illustrated above has proved effec- tive. It is simply a wooden pole or broom handle suspended ‘in midair by wire. Braces of fine wire are used at each end to prevent the perch from swinging.—C. M. WILcox.

Pipe Wrench Used as Vise FEW things are more awkward than to have to do any work with pipe when no vise is at hand. In such an emer- gency, a pipe- vise may be improvised by nailing or clamp- ing a pipe wrench of the steel handle type on the work- bench or any con- venient place. In oneinstancea heavy pipe wrench , was bolted to a ~ repair truck. PIPE WRENCH 4 VISE For holding pipe Be October, 1% Stop Wasti Coal : haul fewer ¢ to ‘‘fire up’’—have your home y and balmy—SAVE MONEY by stoppj your fuel dollars from going up the Make your heating plant MO EFFICIENT with the ; CROWN Fuel Saver A scien device, e installed - furnace which mi supply ; super- heated air (0 et with th gases over th fuel beg Utilizes many heat units which wog otherwise be drawn up the flue. Bri the fire to the top of the bed of coalg where it does the most good. Warrante to save 20% of coal bill—often sayy much more. Successfully used for 19} years. 4

e e * i Write for Description} A detailed description of the CRO its scientific principle—application—eg splendid results—has just been issue Write for it, especially if you buy cod for home, school, theatre, church greenhouse. You can use cheaper grade fuels with great success. Distributors 4 wonderful sales pro sition and exclusive tert Wanted tory for a few more distributors. WRITE TODAY—ask # your locality is open. ag CROWN FUEL SAVER C0, 110 N. Tenth St., Richmond, Ind.

Daytime System— Nighttime protectior for your tools pro vided by ng = Gerstner Tool y for MACHINE and TOOLMAKER Write for Free Catalo ; H. GERSTNER & 522 Columbia St., Daya

> “LIGHTING = et Ready to hang. Direct from the manufacturer. = Completely wired including glassware. Send for New Catalogue No. 27 (Just reduced prices) : Special proposition to Dealefs <4 ERIE FIXTURE SUPPLY CO. Desk A, Erie, Pa.

1 Postcard $9.00; Note $13. 00; shatter

ea for samples of th f thew, Pork pad Fige Bie © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

Page 111

POPULAR SCIENCE MONTHLY More Stations 3 On the Air | DAVI D youu want to hear them all— * but one at a time. The Grimes Circuit in the Grimes Inverse Du- plex receiver will give you the sharp tuning desired. Greater volume, dis- . tance range and a tonal quality SUPE R- SELECTIVE you've never heard before are also yours in this remarkable instrument. RAD I '@) Dual operation of the tubes, pro- viding two stages of radio frequency, vacuum tube detector and three stages of audio frequency amplification, gives you the energy of a six tube set with the economy of four tubes. A super power switch gives tremendous reserve power for distant stations. A new form of inductance—the twin cylinder coils and straight line con- densers allows you to tune in the de- sired programs and shut out the rest. BABY GRAND Duplex Model, using 3 tubes with the power of 4 tubes. In two-tone mahogany cabinet, housing all batteries. (Without $49.50 Accessories) West of Mississippi $60 EMPIRE MODEL, in reality a 6 tube set operating on 4 tubes. Enclosed in 17th Century Solid Mahogany French Cabinet, hous. ing all batteries. (Without Accessories) $1 25 David Grimes ITALIAN RENAISSANCE MODEL Products of Super-Tone Utilizing 4 tubes with the efficiency of 6 LOUD SPEAKER tubes. Built in a Renaissance Cabinet of David Grimes Radio ites mice disnh two-tone Mahogany and Wal- ‘oe aca $95 nut concealing all batteries. $1 25 & Cameo Record Corporation distortion .. (Without Accessories) i D nstration Ask a Grimes Dealer for Demonstra 1571 Broa dway,New York, N.Y, @® This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

Page 112

POPULAR SCIENCE MONTHLY Oc tober, 1925

—————____

MOMs Works

ied THE modern space-saving apart- ment the old-fashioned sewing-ma- chine has been supplanted by the small electric portable. A convenient place for the electric sewing-machine is seen in this sewing-cabinet set into the wall close to a window. The opening, which is cased all around and provided with two small doors, may be of any desired height and fitted with shelves to suit one’s needs. But the shelf holding the electric machine should be set 29 or 30 in. above the floor. The upper door is a drop-leaf that opens downward to shelf level; it is supported by hinges and two strong chains. The machine is drawn forward

“ATKINS” Always Means Quicker, Easier Metal Cutting! OU—whenever and wherever you cut metal—can save time and money by using genuine

yy | = — ZN 72. TONGUE AND GROOVE/MHY Y ELECTRIC LIGHT PLUG 5 |} 2-0" \

NG

YY)

ZZ AS —= PANELIN FLAP FLUSH ON INSIDE HINGE OF FLAP

SS <~

WW SS eee Machine Cabinet Built into Wall By A. May Holaday

on this handy table and the cord jg plugged into an electric outlet inside the cabinet. A dining-room chair is of proper height to use with this table. Any narrow wall cabinet or china cup.

make an unusually efficient vario- coupler for a radio receiving set. The only outlay will be for a spool of No. 18 The name ATKINS on the double cotton-covered magnet wire for blade means the highest grade ‘‘Tungsten Alloy’’ steels, chosen by the great Atkins laboratories, tempered by the exclusive Atkins gas and oil process, “‘file tested’’ to prevent breakage and insure JR | | | cutting job, tosave you time, money and material.

How the coils are wound and the parts assembled. The coils "e€ mounted to reduce all| possible electrical losses to a minimum

; SLEEVE

extra life and value. METHOD OF WINDING COILS

Ask YOUR Hardware Dealer for genuine ATKINS ‘Tungsten Alloy AAA” Hack Saw Blades, “All Hard” or ‘‘Non-Breakable.” We'll gladly send you the Atkins Hack Saw Chart and our valuable booklet ‘‘Atkins Saws InThe Shop”’ E. C. ATKINS & CO. Established 1857 Leading Manufacturers of aws, Saw Tools, Saw Specialties and Machine nioes. INDIANAPOLIS, U.S, A. Pgs a ; soe } \ X\ \\ ‘ \) N ct sy x N hy \ V5 WY Uy Vp \ “| winding the coil, as the other materials \ usually are to be found about the ‘house. : Winding forms are made by drilling holes in a board and setting pegs as TUNGSTEN shown. The primary or stationary coil \ fe is 4 in. in diameter and has 80 turns ALLOY ‘iW tapped at every 20turns. The secondary

ROTOR SHAFT - a

board already built in the house, if 10 in, Atkins “Tungsten Alloy”’ Horizontal section through the cabinet, and de- deep and 2 at. or more wide, may be Eiaal aad Bla dine tail showing the framing and door construction converted into a similar sewing-cabinet, n° ia hi “a ao A Variocoupler of Exceptional Efficiency art—free—tells the rig Atkins blade for every metal At SLIGHT expense any one can _ orrotor coil is 214 in. in diameter and has 40 turns. The turns are bound together with thread, making the coils practically self-supporting. The rotor shaft, sleeve, and subpanel are wood, although hard rubber or other insulating compositions may be used, if preferred. Holes are drilled in. both panels to allow the passage of the shaft. The sleeve is slipped over the rotor shaft and fastened to it with a brad. A threaded rod fastened with a nut at each end is used to draw the subpanel toward the main panel. The proper tension on the rotor shaft is obtained by tightening} one of these nuts. The subpanel also is fastened to the base of the set with brads. A knob or dial is fitted to the shaft. The primary coil is suspended beneath the secondary rotor by strings that are attached to the subpanel and to two supporting posts.—E. L. GOODWIN.

Toy Dresser Made from Box HE dresser illustrated, which is 11 by 16 by 23 in., was built from wood taken from an old box and a small mirror. It was given three coats of white paint and one of ivory enamel. —ALBERT Ho-

A doll’s dresser BERG. that cost little “

ee

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

Page 113

e cord is inside the air is of table. china cup- e, if 10 in, 2, may he 1g-cabinet, ncy ter and hag .d together practically 1 subpaned er or other be used, if 1 in. both ' the shaft. rotor shaft _ brad. A nut at each nel toward tension on - tightening | anel also is with brads. » shaft. led beneath gs that are nd to two JODWIN. »m Box s dresser ost little a How to Cover Cracked Plaster (Continued from page 71) in using only the regular studs already in place, but it certainly is worth while to eut away the plaster and lath for insert- ing an extra stud where a well formed panel cannot otherwise be obtained. Having decided the plan of panels on the ceiling and taking into account the width of the decorative strips, strike guiding chalk lines and nail across the joists 1 by 3 in. furring strips (Fig. 1). Preferably these should not be more than 16 in. apart from center to center. Border the edges with 1 by 4 in. strips. With a straight edge try these for aline- ment with themselves and the rest, driving shingle points under the low places to bring them to a line. Tt? wallboard may be cut easily with a fine saw, or by scoring with a knife and breaking off. If one person must put it up alone, make a T support to hold up one end. Patent clinching fasteners for the fiber boards are to be recommended for use on intermediate furring strips, as they eliminate nail holes in the centers of the panels. If these are not used, nail the centers every 8 in. with l-in. No. 16 brads, driving the heads nearly flush and countersinking with a nail set. Then nail the edges with No. 16 1 or 1% in. flat-head nails 10 in. apart, keeping at least 4 in. from the edges. Leave a */,-in. space between the boards. If the wall plaster is reasonably straight, apply the board directly, but if it is crooked, nail 1 by 3 in. furring strips to the studding. In either case remove the picture mold, and if furring is used, take up the baseboard as well. This may be used again if pried off carefully. Pull the nails from the back with pliers or cut them off flush rather than pull them from the face; in this way nail hokes and prob- able splintering are avoided. Take off any plate and chair rails, but do not remove the side or head casings of doors and windows. Since the joints between the window aprons and the stools are hidden, it is well to pull off the aprons also. Notch out the back edges of the projecting stool ends, as in Fig. 5, to allow the board to ‘be slipped in behind. Where no furring is used, locate the studs by tapping the plaster with a hammer, and mark their positions. Stand the board on the base and nail the top with four 2-in. flat-head nails. Strike a white chalk line for the studding and nail the centers with sixpenny finishing nails. Use flat-head nails at the edges, except where they butt against the casings. Fit snugly around all casings. For the average room, decorative strips 214 in. wide (stuck from stock 3 in. wide) and 1% in. thick are satisfactory. The profiles detailed in Fig. 6 are neat, the third design being the best, though somewhat the hardest to handle. If the Plain profile with the rounded corners is used, most of the joints with the cornice and base may be butted. If the edges are (Continued on page 124) POPULAR SCIENCE MONTHLY 123 | | | Ee, ort SP éctakean: Yeate (Gesu REET Education is the process of conquering one’s environ- ment. The widening of this circle ends only with life. Every day the.world should be made new by some new acquisition of truth. formation.” Huxley says—‘‘All education is habit Those who form the Encyclopaedia habit— a few minutes a day with Nelson’s—are the educated and progressive men of their day. JOHN H. FINLEY, Editor-in-Chief. * | ie BT Oy ie Perpetual Loose-Leaf ENCYCLOPAEDIA Research Bureau for Special Information " THIS BEAUTIFUL FRENCH STYLE BOOKCASE—FREE! Educational Reading Courses _ A Reader’s Guide to Nelson’s Loose-Leaf Encyclopaedia including thirty-three courses on as many subjects—from Aeronautics to Zoology—is furnished without cost to all sub- scribers. These courses are declared by educational authori- ties to be equal to a college course in each of these departments. Nelson’s Free Research Bureau FOR SCIENTIFIC REPORTS AND SPECIAL INFORMA- TION AND CORRESPONDENCE. Nelson’s is entitled to free membership in this Bureau. Every purchaser of } If at any time you are in doubt on any subject, old or new, write to this Bureau with the positive assurance that you will promptly receive the latest obtainable and most dependable information. THE GREAT AMERICAN ENCYCLOPAEDIA NELSON’S PERPETUAL LOOSE-LEAF ENCYCLOPAEDIA—the Great Ameri- can Reference Work-—is published by one of the oldest and largest International Publishing Houses. The Editor-in-Chief is John H. Finley, LL.D., L.H.D., Editor, New York Times; the Canadian Editor is Sir Robert Falconer, K.C.M.G., D.Litt., LL.D., President of the University of Toronto; the European Editor is Sir Henry Newbolt. Its staff of contributors includes men and women foremost in scientific, professional and public life, who are themselves making history. This Great American Encyclopaedia is always an authority in government departments, libraries, schools and educa- tional institutions everywhere. It covers every field of knowledge, from the beginning of the world to the very latest activi- ties of the present day; by means of the Loose-Leaf binding device, it is the only Encyclopaedia always up to date—it cannot grow old—it is always dependable. Originators of the Loose-Leaf Reference System EXCHANGE Send for price list giv- ing amounts allowed for old Encyclopaedias to apply as part payment on a new Nelson's Perpetual Loose-Leaf Encyclopaedia. THOMAS NELSON & SONS Publishers for 125 years P. S. 10, 381 Fourth Avenue, New York City ' Please send me your portfolio of sample pages, beautifully illustrated, containing color maps, plates and photographs, and full information how, by easy monthly payments, I can own Nelson’s Perpetual Loose-Leaf Encyclopaedia and receive FREE bookcase and membership in Nelson’s Research Service Bureau for Special Information. This must incur no obligation whatever on my part. Stettis st caccecedua (Adv. Copyright, 1925, Thomas Netson & Son) © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

Page 114

Paci lr lacdeg atte a sa Pe - - - _ ae eT Se eae poceatet Cats Twang Look for the famous blue center October, 195

- SEG ite Wome Work shhopl

INGERSOLL DOLLAR STROPPER Robert H. Ingersoll, originator of the famous Ingersoll Watch, offers you his remarkable new invention that brings back keenness to used blades, makes them last longer and ive clean, smooth, comfortable shaves. Already satisfy- ng thousands. Hundreds of Shaves From Every Blade The INGERSOLL DOLLAR STROPPER makes it possible to keep razor blades good for a whole year — HUNDREDS OF SHAVES FROM EVERY BLADE! That means no more dis- carding blades after

10 Days’ Trial

afew shaves. Re- sharpen them. Prove that the and SAVE Ingersoll Stropper $5 to $10 is all we claim. Send

$1.00 for outfitcomplete J with 12-inch Strop and Patent Nick- el-Piated Holder. Automatically puts scientifically keen edge on blades! Money c ten day trial doesn’t convince that Mr. Ingersoll’s new invention solves your razor blade troubles. Write today, mentioning make of razor used. ~ Agents: Write for Proposition. ROBERT H. INGERSOLL, Pres., New Era Mfg. Co. Dept. 7810, 476 Broadway, New York City a year.

CARTER New “IMP” Rheostat (Pat. Pend.) $1.00 Half Size

Smallest rheostat made. Diameter 1% inches. Projects but_% inch back of panel. Single hole mounting. Complete with pointer knob. New ex- clusive Carter method of contact. Positive, smooth, silent. Same Carter high quality and standard of workmanship. See one at your dealers today. Write for information on other Carter original Radio products. Binet Any dealer can supply. & In Canada—Carter Radio Co., Ltd., Toronto if Cc arter.

| the wallboard, cut off the projecting ends —_—__arrey| How to Cover Cracked Plaster | (Continued from page 123) | molded, joints with the cornice must be made by mitering in the depth of th molded edge and butting the plain Width | (Fig. 8). Many mills will run specig moldings on the strips for a small ad. tional cost for setting up the machine | It is common practice in some sections || of the country to use plain panel strips | and separate panel moldings, which can | be obtained in various styles. The ceiling member of the cornice, jt| will be noted, is )4 in. wider than the lower wall member, so that the same width will be shown by both pieces when they arein place. Always use, if possible, such widths as will cut without waste| F from stock sizes. Put up the ceiling member first, either | mitering the corners complete (Fig. 1), or | mitering the molded edges and butting the widths as previously explained. Cut} the strips to length, measuring them in. | dividually for the places they occupy,| and mitering back the edges. Tack one| end in place while the miters are scribed on the cornice. Then take down and cut out the miters with a chisel, cutting inside the line and trimming straight the butted portions, acting on the assumption that it is easier to cut out a little more wood in fitting than to add to it.

r* THE strips are cut a trifle long, and the ends placed with the centers bowed down, the leverage developed in straight- ening the piece will go far to close irreg- ularities in the joints. Be very careful, however, to keep these strips straight, and to avoid such pressure in any one that joints in others already nailed up will be opened. Scrape and sandpaper the joints. Next, run the wall member of the cornice. Butt the upper edge of this member against the ceiling piece, first beveling the edge back from the face to insure a close fit. Put up the two long sides and cope the end pieces between, also springing them into place. The joints between wallboard and casings now must be hidden. Figure 6 shows desirable forms of back band to run around the casings, but the thickness will vary in each case, according to the thickness of the wallboard. If the casings are molded and mitered, as in Fig. 3, simply miter the back band around them; but if the ordinary butted casing with neck and cap mold is used, as in Fig. 4, other handling is necessary. Remove the cap mold before applying of the neck mold, and notch the front edge to fit against the lip of the back band. Then miter the band around, and replace the aprons under the windows. Next, apply the panel mold for the base (Fig. 7), and cut the decorative strips between it and the cornice. The corner strips are molded on one edge only, one piece being 14 in. wider than its mate, so that when butted to- gether on the edge as shown, they will expose equal widths. ‘ (Continued on page 125)

a

rIS] This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

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October, 1925 POPULAR SCIENCE MONTHLY 125 ‘Ober, 19% nice, it than the he same ces when possible, ut waste st, either ‘ig. 1), or | butting ed. Cut them in- ’ occupy, Tack one re scribed lown and raight the sumption ittle more a 1, cutting long, and ers bowed n straight- ‘lose irreg- ry careful, ; straight, 1 any one nailed up sandpaper er of the xe of this piece, first he face to > two long ; between, yoard and Figure 6 k band to e thickness ling to the id mitered, back band ary butted lis used, as necessary. e applying ecting ends e front edge back band. and replace bld for the decorative nice. Hed on one 2 in. wider butted to , they will oes Short Cabinet Clamps Used for Holding Long Work HEN about to glue up a long buffet, I found my cabinetmaker’s iron clamps were much too short. I therefore made three strongly mortised hardwood frames 14 in. wider than the buffet and about 3 in. longer, di and cut 12 wedges = 2% in. wide, ta- Gluing up a large buffet pering from 14 to 2 in., as shown in the illustration above. After the buffet joints had been glued, the frames were placed as shown and sup- ported by the pieces A. The wedges B were inserted as indicated and spacing boards C were placed so as to exert pres- sure on the wedges of the middle frame. The clamps then were used to squeeze the wedges together and draw the joints tight.—I. H. C. How to Cover Cracked Plaster (Continued from page 124) If it is necessary to fur the walls, use 1 by 3 in. stock and then apply the board in the same manner as on the plaster. It will be seen that the board projects its | thickness outside the ordinary casing. This necessitates the use of a panel mold to cover the joint and the lip in this case clasps over the wallboard instead of the casing. If judgment is used in this, all bungling massiveness in appearance can be.avoided. In the case of a brick or tile house, the walls must be drilled and plugged with wooden cylinders 34 in. in diameter and 1% in. long, to provide nailing for the furring strips. To prevent entrance of moisture, waterproof the walls with asphaltum or some other suitable pro- tective paint. Fill nail holes with white lead putty made by mixing whiting and white lead in oil, or whiting and ‘the sediment found in paint cans. The panels are best painted with flat colors, except in kitchens or other rooms subjected to moisture. Mix with the first coat one-third of hard drying varnish, or, if the panels are to be papered, give them a priming coat to facilitate removal of paper in later decorating jobs. Paint or stain the decorative strips very nearly, if not exactly, the same tint as the panels, getting color contrasts through the use of draperies. Other applications of wallboard will be descri in an article, “‘Home Beau- tifying with Wallboard,” which will be published in an early issue. feneummeast It makes life's writing easier~ R every age and every station—for men, women, and children— the New Remington Portable is an invalu- able helper. For the child it is an inspiration which facilitates com- position and hastens the writing age. For the student it saves valuable time for athletics and other school activities. Then too, typewritten work brings better marks, and correspondence has no burdens. For the traveler it has extreme lightness; for the profes- sional man it combines every advantage; and for all it is a time-saving convenience, possessing in compact form all the writing merits of a larger machine. Our NEW model has several mechanical improvements that give it an efficiency never before equaled in a portable typewriter. It is the lightest and most portable Portable with 4-row standard keyboard; it is the most compact Portable; it has the longest writing line of any Portable; it accommo- dates full width paper and long envelopes; it has the finest touch and action; it does beautiful work; its dura- bility has been proved; and ail the writing is always visible. Be sure to examine the New Remington Portable, or write for our illustrated “For You —For Everybody.” Address Department 67. REMINGTON TYPEWRITER COMPANY 374 Broadway, New York—Branches Everywhere Remington Typewriter Company of Canada, Limited 68 King Street, West, Toronto Remington We believe we make the best typewriter ribbon in the world — and its name is PARAGON © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. The New Model Now Available The New Remington Port- able is sold by Remington offices and dealers every- where. It is backed by a service that is universal,

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126 iis illustration pictures the take-off of the winnin flight and in the insert is the radio equipment carried. (Burgess ‘A’, ‘B’ and ‘C’ Batteries furnished the electrical energy to operate the set.) When the Goodyear III won the right to represent the United States at Bel- gium, Burgess Radio Batteries supplied the electrical energy for the operation of the balloon’s radio equipment. Almost every day from somewhere in the world news comes to us of new Burgess adventures. And that Burgess Batteries have con- tributed their bit in so many interesting events of sport, commerce and science re- flects the esteem in which they are held. “Ask Any Radio Engineer” Your own radio dealer down the street sells Burgess Batteries. He probably sells the famous Burgess Flashlights, too. BURGESS BATTERY COMPANY GENERAL SALES OFFICE: CHICAGO Canadian Factories and Offices: Niagara Fallsand Winnipeg © | (vt | BURGESS | BATTERY | BPR «soussecash ey 2 tak mani] | BURGESS RADIO'A Pee i @® > This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. POPULAR SCIENCE MONTHLY October, 1925 WEioMe Workenop| Fitting Up an Attic Room (Continued from page 76) wedging the jambs) and 6 ft. 714 in. high (allowing for a 6 ft. 6 in. door with ! Yj in. to spare for leveling the head jamb). If possible, use a regular stud for a side trimmer; but in any event, since the space above is so short, run the trimmer to the ceiling. The door, it will be noted, is located by the hall opening. Start spacing the studs from the other trimmer or, if the space is small, divide evenly, asshown. This, of course, is not regulation procedure in the case of an ordinary partition of full height; but it is best for such a case as this, particularly when wallboard is to be used. Spike into the head trimmer from the side trimmer with two or three 16-penny common nails, being careful to keep it level. On the backs of the side trimmers nail three blocks to catch the back edges of the door casings, and put blocks at the corners of the room to insure nailing for the base- board ends. HE other end of the room is built in about the same way, while for the end of the closet the gable studs are used, if such are present. Figure 7 illustrates the side wall. This is nailed together on the floor and raised afterward, but careful vertical measure- ments should be made to make certain that, when the upper plate is brought against the under edges of the rafters, the wall will come plumb. Above the upper plate a space of 8 in. remains, and if the room is to be plastered, blocks must be fitted between the plate above the studs and against headers of 1 by 4 in. boards cut between the rafters, as in Fig. 5. For wallboard, nail in the headers flush with the under edges of the rafters and let them show 2 or 3 in. above the point of intersection of the wall. Fill the space above the plate with a 1 by 4 on edge and notched about the rafters (Fig. 6). Between the studs of the end walls, following the slope of the rafters, nail pieces of 2 by 4 as backing for the upper edges of the wallboard, as in Fig. 2, and 31% ft. from the floor cut in fire blocks for additional stiffening. Wherever corners occur, backing must be provided to carry the edges of the wallboard. Side walls and sometimes end walls should be braced by cutting 2 by 4 in. blocks between studding, as in Fig. 7. Ceiling joists are placed level at each end wall, the ends butting against the under edges of the false rafters. The others are spiked to the sides of the rafters, and must line with each other. If a straight-edge is nailed to the ends of the end joists, the others can be rested on them and nailed up without further trouble. Bring the rafters to a line if they are of uneven width, by shimming carefully under the narrow ones with thin strips of pine.—E. M.L. How to continue from this point will be told in the third article of the series in next month’s POPULAR SCIENCE MONTHLY. Save *44.00 on this Beautiful White Enameled Kitchen Cabinet HIS handsome white- enameled kitchen cabinet would cost $65 if bought in a store. If you are handy with tools you can make it at home for $21—or less. A clear sav- ing of $44. One feature of this cabinet is a self-contained.seat. An- other attractive feature is the roomy china closet occupying the middle section of the top of the cabinet. Besides the china cupboard, the top section contains a flour-bin and a closet for sugar, spices, and coffee. The bot- tom section has one large cupboard and three drawers, the lower one being a metal- . lined bread and cake con- tainer. There are two large boards that pull out. A blueprint with a bill of material and instructions for making this beautiful cabinet can be secured by ,sending 25c to PoputaR Science Monty, 250 Fourth Avenue, New York POPULAR SCIENCE MONTHLY 250 Fourth Avenue, New York Gentlemen: Enclosed is 25c for which please send me blueprint for the Popular Science Kitchen Cabinet including all the latest features— the | nov coin: Whe measu: inches, both gs genera Renee

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er, 1925 1et te- inet in a with ome sav- inet An- s the ying » top oard, is a ugar, bot- large wers, 1etal- con- large sill of is for \binet nding ITHLY, fork ome oe ee ot y fork ease send ir Science the latest ,oe ee 6 een ee Home Workshop Chemistry Simple Formulas that Will Save Time and Money and other EASPOONS household units of measuring are used in the Home Workshop Chemistry column whenever possible to simplify common the making up of formulas. Judging from letters received from readers, the mere mention of grams and cubic centi- meters makes a formula seem compli- cated. Yet it is a simple matter to convert one measure into another with sufficient accuracy for ordinary purposes. The proportions are what count in making up a formula. For instance, if ounces are given, the process need not be carried out in ounces; any convenient unit of measurement may be used. The only thing to be considered is that the quantities are reduced or increased in the same proportion throughout. Here is a table of useful equivalents: 1 0z.= 2 tablespoons 1 teaspoon = oz. or 1 drm. 1 oz. = 28 grams (weight) If one desires to weigh the chemicals used and no weights are at hand, coins can be used. Using coins in place of chemist’s weights A half-dollar = 121% grams A quarter = 6% grams A dime = 24grams \ In avoirdupois: A half-dollar= 200 grains A cent=50 grains A quarter= 100 grains A dime= 40 grains A nickel= 80 grains 1 0z.= 4371 grains Therefore, 2 half-dollars (400 grains) and a dime (40 grains) combined are near enough to serve as a l-oz. weight If your scales are without a scale bar and it is desired to obtain a weight of, say, 30 grains, place a nickel (80 grs.) in one pan and a penny in the other. Then add the chemical or whatever is to be weighed to the pan holding the cent until a balance is obtained. Any number of combinations can be used in this manner to find intermediate weights. For average purposes: 450 drops=1 oz. or 30 cubic centimeters I large water-glass holds about 6 fluid oz. 1 pt. water=1 Ib. Many almanacs and general hand- books contain tables showing the com- parison between the Centigrade and Fahrenheit scales and these can be con- sulted on the relatively few occasions a question arises. When it is necessary to convert metric measurements of length into feet and Inches, either purchase a rule that has both scales or consult the tables in any general handbook. POPULAR SCIENCE MONTHLY James J. Hill, one of America's greatest railroad pioneers. Some boy who, today, is acquiring his elec- trical and mechanical knowledge with Lionel Model Railroads may be the James J. Hill of the future. LIONEL TRAINS , are Models— not mere “Toys” N appearance and in operation Lionel Model Trains are just like real railroads. There is a thrill in operating them that you cannot get from any mere “‘toy’”’ train. The only difference between Lionel Model Trains and real trains is the size. Lionel Model Trains and Railroad Acces- sories are designed from real railroad equip- ment by Lionel erigineers for boys who want things exactly as they should be. For twenty-five years Lionel Model Rail- roads, Multivolt Transformers, and Model Railroad Accessories have held their lead- | ership. They have kept pace, year by year, with the improvements and developments of real railroads, They are up-to-the-minute and are the lowest priced consistent with qual- ity. Take Mother and Father with you to see the latest Lionel Locomotives, Coaches and Accessories—on display at all the best stores. There is a Lionel Outfit priced to suit every purse—complete outfits from $5.75 up. THE LIONEL CORPORATION Dept. B, 48-52 East 21st Street, New York City Write today for this beautiful new 44-page catalog, illustrated in actu. alcolors. Sent free. 127 Lionel Auton-aticTrain Control. The greatest achievement in model railroad engineering. Starts and stops trains automatically. Just one of the many wonderful realistic railroad de- vices in the Lionel line of Accessories. The Lionel Bell Warning Signal —As the train approaches the grade crossing, bell automatical- ly rings — stops ringing as soon as train has passed. Steel construction throughout. Lionel “Multivolt” Transformers, Ever-re- liablepower plants. Run all trains best. A type for every size train. | OTe) x FOR DHE PATENTED LIONEL FEATURES JIONEL!°TRA __ “"MULTIVOLT” TRANSFORMERS riS] This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

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128 Heats Homes With AMAZING NEW LIQUID GAS Now—right in your stove, you can have the con- venience of automatic heat—any degree—by simply turning a valve. Cheaper, cleaner, drudg- ery saving. Soremarkable has been the success of this new invention that Pat Schaefer guarantees to heat your home this new, easy way on thirty days’ trial— and you pay nothing if you do not get perfect heating or cooking sat- isfaction. O you want to end forever the soot, ashes, dust and drudgery of dirty coal and wood—the worry of strikes and short- ages, poor quality and high prices? Would you accept an opportunity to try out in your home on thirty days’ trial a wonderful new inven- yy, tion which does all that—and ives gtoye, range or you more dependable heat besides? furnace. Fits All Stoves ot a Without Change =| Or Never has such an extraordinary offer been made! Why? Because at last, an oil burner has been per- fected which has revolutionized the industry, A small quantity of kero- sene (coal oil) will heat your home for hours—you get any degree of heat by simply turning a valve. .: Instant heat, any And any stove, heater, or furnace degree at turn of can be equipped without drilling walves. holes or any other change. In- stalled in a few minutes, thn | AGENTS perfect heat to suit any day— mild or zero weather. Soere time workers, Thirty Days’ Trial— | (= otis amusing Mail Coupon ~—y AT aid out to agent:. Pat Schaefer will send this mar. | Q2¢ ma" made more velous invention to you on thirty | Free Territory, cash days’ trial. You do not have to J Bonu, end Sample pay a cent for it if it does not do | ducers send name everything he claims for it. Be | Schaefer, President, teady for Winter. Save buying | Simply ask him for coal. Send the coupon atonceto |} Selling plan. OLIVER OIL BURNER CORPORATION Dept. M-340 Jth and Market Sts. St. Louis, Mo. OLIVER OIL BURNER CORPORATION Dept. M-340 7th and Market Sts., St. Louis, Mo, Please send me at once your booklet, full details of | your low price and free trial offer. Iam interested in sanaeed {] Cook Stove [] Heater [] Furnace any heating PRs tre sbsonsevetensovnssccccscsbsvescossnecveecsees | i skrcnutincwinvcbevenssees eye re | to ii cbghsuseesucseo cows sense Sager an | A SS A A Se oe POPULAR SCIENCE MONTHLY Sawhorse Aids | Mavy house-own- : ‘ ers endeavor to in Repair Work | make the various repairs necessary in keeping their homes shipshape without the aid of a good sawhorse. Yet a saw- horse is as essential for odd jobs as a bench is for cabinetwork. It can be carried wherever needed and used both as a support for work that is to be sawed, os planed, chiseled, assembled, or painted, Pr til. A a A and as a platform on which tostand. For Quick Detachable ~ repairs that involve the handling of long ‘ boards, doors, full sized window-screens, RowboatMotor | storm sash and doors, and the like, a pair | Gow pay Hight Weight Speedy, of sawhorses is desirable. tionless. Starts on aquarter turn. | There are, of course, several types of you 0, rb heparin pt die wooden sawhorses. While few carpen- | 3ust ride and enjoy the greatest of j ters and, I suppose, fewer amateur wood- | Speed up forracing. Great power. workers, are familiar with the design il- ee ee et lustrated, it is much better than the] cially the famous PropelloPump.Only j Elto has it. Write today. " ELTO OUTBOARD MOTOR CO. Dept. W “SQ le Evinru Pres, Manf’rers Home Bidg. Milwaukee, Wis. A sawhorse that gives good serv- ice for odd jobs able to play a saxophone. ThenewYork Saxophone is easier to finger, easier to blow. DAYS FREE RIAL With our free lessons you .. can be playing popular tunes \ in ashort time. You can get })) this wonderful instrument, with its superb tone and per. fect workmanship on six days free trial in your own home Then if you decide to keep it yw can take ten months to pay. Write at once for free saxophone book ®\ let. Other York Band Instruments BY sent on the same easy terms, Fret literature upon request. J. W. YORK & SONS Dept. 925-3, Grand Rapids, Mich b >N average sawhorse. Every carpenter who GORD has used mine, thereafter has made his Peso own sawhorses like it. Poy Ser bu This horse has a double top made of 2 by 4’s separated 134 in. by spreaders. This affords a solid stand for ripping boards. ‘The recesses at each end allow doors or sash to be placed in them for trimming. The wide top gives more foot room when one has to stand on the horse. The bottoms of the legs, furthermore, are exactly 4 ft. apart lengthwise and 16 —a MANY EARN in. apart crosswise. The advantage of a : $75. to $150. Weekly ‘ this, from the viewpoint of a carpenter MR, |NSTANT-WELD Welds Rubber Instantly. ' . : . etter i ° i h iz. working on new construction, is that the ng. ONGH ONZALWAYS ON. No Heater a Cement required. Repeat orders sure. Big [ sawhorse can be placed either way on f Profits. Appoint sub agents. Write today. ° ee ° 3 at. TOURISTS’ PRIDE MFG. Co. ordinary joists set 16 in. center to center. Desk No.30-J Minneapolis, Minn. [| To make the horse requires 2 pieces 2 by 4 by 48 in. for the top; 2 pieces of 2 by 4, 334 in. long, to serve as the spreaders; iit pape 4 pieces 34 by 414 by 26 in., tapered to 214 ete Toeay : Eor hy in. wide at the bottom, for legs; and 2| § 2 : rs) end braces, 34 by 74 by 12 in. Any 64 Page Catalog common wood will do, but the parts RAD 10. B A R ey. INS should be sound, especially the legs. RANDOLP HR AD 1 O CORP. Rasiner ae dene 427) 159,N. UNION AV: Dept:.3. CHICAGO, ILL © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

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ctober ‘ 1925 ~ essons you opular tunes You can get instrument, tone and per: ip on six days ir own home 2 to keep it you hs to pay. Write axophone book ind Instruments asy terms, Fret juest. Weekly | ubber Instantly. | than vulcaniz- #4 ON. No Heator §— rders sure. Big [4 3. Write today. ff MFG. CO. ¢ eapolis, Minn. E log of ;AINS CORP. ICAGO, ILL October, 1925 POPULAR SCIENCE MONTHLY 129 Whip Shape ome: (Continued from page 128) First the top pieces are mortised to receive the legs. Then the spreaders are nailed in place 4 in. back from each end. The legs next are nailed on; then the praces. Forty-four eightpenny common nails are used.—SAMUEL I. MYERS A.uminum paint How to ow has many uses in Aluminum aint keeping a house shipshape because of its exceptional covering qualities and durability. One should. buy the aluminum bronze powder and varnish separately and mix them as needed. Any good spar varnish makes an acceptable vehicle. To make aluminum paint, the powder should be added to the varnish in the proportion of 2 lbs. powder to 1 gal. of varnish. This proportion can be ob- tained by measuring out 14 pt. powder (6/16 pt. to be exact) in a measuring-cup, pouring it into a container, then measur- ing 1 pt. of varnish in the same cup and pouring it over the powder. When the powder and varnish have been stirred thoroughly, the paint is ready to apply. If the varnish is too thick, dilute it with from 10 to 20 per cent turpentine before measuring out and mixing with the powder. Only enough paint for one day’s use should be mixed at a time, as the mixed paint will lose its brilliance and hiding power after standing for a few days. This paint can be used on metal sur- faces indoors or out. For outdoor serv- ice, however, two coats must be applied to give the necessary resistance to the weather. It will also serve well on wooden surfaces indoors. For outdoor use on wood, the varnish preferably should be diluted with about one-third its volume of boiled linseed oil so as to make a more elastic paint film. According to experiments made: by the Forest Products Laboratory, aluminum paint has a very high waterproofing ef- ficiency. It therefore makes an excellent priming coat for wood. Its high im- permeability to moisture keeps wood from cracking, checking, and swelling from absorption of moisture. It serves equally well as a finishing coat. The more common uses of aluminum paint, such as for finishing radiators, water-pipes, steam-pipes, gas-heaters, fur- nace exteriors, and the like, are well known, but it is equally valuable on many other surfaces, indoors and out, where unusual protective and covering qualities are required.—JUNIUS D. EDWARDs. Protecting IN PAINTING H d woodwork or fur- araware niture it pays to re- move thehardware if it can be done without much trouble. When this would require too much time, it is well to give the hardware a prelimi- nary coat of vaseline. Any paint that gets on the metal, if allowed to dry thoroughly, can be wiped off bodily with the vaseline: (Continued on page 130) SPECIAL OFFER Made Only to the Friends of Poputar Science Monruiy Wovrr it not be grand to have some good friend tell you how you could easily make $5.00—and by a little more work make many times $5.00? For You For Giving a little time to PopuLaR SCIENCE MonrTHLY If you are one of the many readers of POPULAR SCIENCE MONTHLY who find this magazine in- teresting and useful, who feel that they could not do without it, then we know that you will be glad to tell a few friends that you like ‘‘Popular Science” and that you want them to read it too. We have a plan we should like to tell you about, a plan by which we shall be glad to pay you Five Dollars, if you will undertake a few hours work for us. And if you can devote more than a few hours to our plan, you can make many times the first five dollars. Won’t you write your address on the coupon below and send it to us today? We will explain the plan to you by return mail. : «==="SIGN THIS COUPON TODA Y="*=== POPULAR SCIENCE MONTHLY, 250 Fourth Ave., New York, N. Y. Gentlemen: Please tell me about your plan by which I can earn $5.00. Name Address Occupation 10-25

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POPULAR SCIENCE MONTHLY Qe |oloune (Continued from page 129) Bracing In MAKING fall re- pairs to the out- Eave. Troughs side of your house, it is well to ex- amine the eave troughs if they are of the suspended metal type, and make sure that they are rigid enough not to be pulled out of shape and otherwise dam- aged by ice and snow during the coming winter. Damage of this : kind, which is Naveenny, x. quite common, can : be prevented in = | most cases by pro- SS im * ic . itj [ ullaby | viding additional braces for the eave- 140-page Book full of life. size ruled forms, each one completely filled in. The an- swer to problems of account- ing and record keeping for any business or profession. Send for this FREE Book today re : ager John C. Moore Corporation , am | troughs. they SSs (Established 1839) Radio-Crooned e ty Se ED sai H 3025 Stone St., Rochester, N. Y, ’ type hung with wire hangers, twist a Through the air of the length of copper wire in the outer eye of evening, calm and sweet & § | the hanger, draw it up to the roof and dl f wrap it around a firmly driven nail; then comes a Cradie song irom return it and insert again through the a distant city. Then, aS mej eye. Fasten securely, drive the nail | never before, we feel the aE home, insert an eightpenny nail in the . ‘ double wire and twist it until tight. need of radio amplifiers Then remove the nail. Treat each which will bring out, 4 hanger in this way. HEAT Without Coal s Amazing invention does away i with coal or wood. The In- : If the trough is of a molded type, punch | coreg OF ee - strong and clear, just the a small hole at the outer edge and pro- a burns 96% air and 4% oil) pure beauty of music. For §@ | ceed 4s with the half-round style. ad ar igs theheat of coal; Tf baking, Installed withoutdamage if the hangers are of the malleable costovein Sveminutes—tofurnace such moments is the joy type and bolted on, a copper strap /4 in. | jpam hour. Mh say pace kg of owning the one ampli- | wide with a 14-in. hole \% in. from one 30DAY FREE TRIAL andlow a bm | end will serve the same purpose. Insert | {tim ity. Weitat - fo Free} fying instrument selected the hook of the malleable hanger in the an oe lone by world-famed musical l4-in. hole, draw the strap up tightly, bee i “4s . and nail to the roof.—C.W. H. vans tion whether authorities for the purity ‘ ‘ ; furnace. &nternational Heating Co. of its tone: Rauland-Lyric. ‘Dept 125K 417S.14thSt.,St.Louis,Mo . ° N MY i é e We pay $60 a week. Write Mice in Ix my business as Agents: ior PYh.co Sample One a piano dealer, I Pianos have removed hundreds of mice ( Jear-Tone nests from pianos. The repair bills have Cai Jone ranged from $5 to $75. Indeed, it is LTRADE mann nec | astonishing the damage mice can do in a The Wonder-Working Lotion short time to a costly instrument. Use like toilet water. Is positively rec- For a long time I tried to find a way to | | ommended forquicklyand permanently removing make a piano mouseproof, but every PIMPLES, BLACKHEADS, ACHE scheme involved . | | Eruptions on the face or body, Borbeal _ much — Itch and Eczema, Enlarged pores, Oily or 500 great Gs- 15 or Gay Gen, Endorsed by druggists, pense. F inally physicians, skin specialists, barbers, and over i 100,000 men and women test cases, who succeeded it occurred to me with Clear- ~Tone after failing with everything else. V Write to provide the today for my Free booklet, “A CLEA KIN,” 5 =“ telling how I cured myself, after being afflicted 15 years. mice with ma- || & s_ @IVENS, 153 Chemical Bidg., Kansas City, Mo. terial for a nest so that they would not attack | the piano felt. This I did at first by placing in the lower right-hand corner of the piano a hatful of small rags, each about 14 in. wide and 2 in. | long. | ry) That worked well, but later I found a | _ BECOME ‘AN ooo wea ~ pn mm | simpler method. When I have the keys pb Ny bm | off at the time of tuning a piano, I place a TRANSFORMER iL ij | folded newspaper under each register or /@ | compartment directly under the keys. I Executive Accountants and C. P, A’s. coat © : *,° — ® at Onl 6, 000 000 pie The Choice of Noted Music Critics tye | have never known a piano to be damaged | antemthe United States. thers Oa SS) teescle er bias ic Accra : ° . ° or C.P.A. Seapine or mxecntirs accounting positions. by mice if either of these plans was | experience ning under the personal es adopted.—F. X. ALLEN. &. 8. inelading men members of sii Sena of scout Chicago Rauland-Lyric is a laboratory- grade audio transformer de- signed especially for music lovers. The price is nine dollars. Descriptive circular with am- plification curve will be mailed on request. All-American Radio Corporation, 4201 Bel- mont Ave., Chicago. Write for free LaSalle Extension | a University .D ersity .D ept. 1083 1083-H 5S) This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6 na .S2e@eo _ 2 we «a

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rrr: How to C ncaa Couplers for a Model Railroad By Edward E. de Lancey AKING model automatic couplers M of the old fashioned ‘‘Miller’’ type may impress the average model- maker as an unpromising job, especially as these couplers now are obsolete. The writer, however, has made scores of them and has seldom met with difficulties. They are not apt to become uncoupled on curves, but when they do, the “‘check chains’ always prevent a separation of the train. As far as “looks” go, they may offend the eye of one who is accustomed to couplers of the Janney type, but that is a trifle compared with the crude appearance of the too widely spaced cars commonly Parivar. a ir..w Ir. aie... sir. SIP SP. Se SI BUFFER WASHER 4 THICK _ COUPLING HOOKS oP Sarre. aT ie. a Ie... SI... SL Ie. SIP. SP SLIP. SI... SLI... ® rer Sl oe BAA os , a Si (@ i} SS / fe a! 3 — rr ptomeen meee") ann 4 4 y rec- + a lc | CHAINS 1 : ot 4 CHE i | SPRING (F) a = Va xi = arbers t | iN E FIG2 4 | 3, Oily bewb-n. nn G-OU -.._.w--- +. 2 t---! ‘gists, . ‘ : po Fig. 1 is an end view of a coupler and Fig. 2, a plan view, looking down met with. Furthermore, there is a gratifying ‘“‘click’’ in the way in which a train comes together and couples in one’s POPULAR SCIENCE MONTHLY NY The Most Popular Watch in the World wit a tribute to an article to say that over a period of thirty years time more people have chosen it than any other ! Ingersoll Yankees have been chosen by 60 million people—in all parts of the world, in all walks of life. Is there any better demonstration of the quality? Of dependability? Of value? Of genuine service? The Yankee now on sale isa new model with many new features of grace and beauty—clean-cut, handsome and ‘‘easy- to-look-at.” aaa A ww r ri vo ay Tin © al lie’. al lie a en a i a le a a i a i sr 18) hae 12. wr te wr ie yards and stations. The couplings may be made of 3% by 3% by 214 in. wooden strips, cut out with a scroll-saw to the shape shown in Fig. 2. These may be of any straight-grained hard wood, but soft pine can be used, provided a 3%-in. strip of zinc is bound around the sides of the hook and bent so as to conform closely to its contour and fastened by the small brass screws A, B, C, and D. The hooks must be secured at least XY in. below the bottom of the car with No. 5 brass screws (EF), 1 in. long. For locking, a piece of spring brass, in ay ervision ber of C. P. pose (Continued on page 132) i Chicago ition Used by the U. S. WW Gov’t., General Motors, \\ Standard Oil, Ford Motor Co., and other big buyers. \\ © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. Sworn Statement by Frank DePries \ “le po states that he has made $900 in one month’s time, $500in a single day, individual sales of 180, 114 and 105 machines at various times. Mr. DePries has been with our company 8 years. Smith of Minn. reports for one week — 43 hours, 44 calls, 28 sales, and $166.20 profit. Robey, W. Va., quita job at $175 a month and now makes $500 a month with us. AGENTS WANTED ‘\ growing by leaps and bounds, HE FYR-FYT, OMPANY 985 Fyr-Fyter Blidg., — We need more men like these, because the demand for our Super Fyr-Fyteris Sells to garages, stores, factories, schools, homes, hotels, auto owners. Approved by the Underwriters. If you are \\ willing to work and ambitious to make some real money, get our plan. \\ You need no experience. as we train you without cost for the work. No \\) great capital os Good territory going fast. Better write us at once. Dayton, Ohio

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e up-to-date trains Pre tp-bo-date boys VES Trains have all the 1925 improvements. They are the only trains with electric locomotives (Series R) that you can stop and reverse by a touch of your finger on the control switch, located away from the track. You boys will get a wonder- ful “kick” out of this reversing device—making the locomotive stop and. back just like a real engineer. A mere touch of the finger does it! This year you can have an Ives Electric Re- versing Locomotive on either O-gauge or 24-gauge track. Both in action and appearance Ives Trains are exactly like the modern equipment of famous rail- roads. There is an almost endless variety of passenger and freight cars, electric target signals and semaphore signals with electrically-operated arms, bridges, tunnels, stations, and the efficient Ives Transformer. Prices range from the $1.50 mechanical train to the big complete $50 electric outfit. Sold by toy, department, electrical, hardware and _ sporting goods stores. Send for the Ives Railroad Book . Tue 32-page book of Ives Trains and Acces- sories contains illustrations in colors of the full line and tells all about the new 1925 features exclusive with Ives. Mail the coupon today with 10 cents. Tue Ives Manurac- TURING Corporation, Dept. El, 198 Holland Ave., Bridgeport, Conn. —~¥*CTRI> IVES ),20,, TRAINS The Ives Manufacturing Corporation, Dept. E1, 198 Holland Ave., Bridgeport, Conn. Please mail me your 32-page railroad book. 1 enclose 10 cents (stamps or coin). POPULAR SCIENCE MONTHLY Ine Wome Works shor | Couplers for Model Railroad (Continued from page 131) marked F, is placed behind each hook. It must be curled at one end for the attaching screw, G, and curved a trifle behind the open portion of the hook. An uncoupling lever (H, Fig. 1) must now be made and pivoted on the left- hand side of the platform, through the slots already provided. A ratchet rack (I, Fig. 3) for holding this lever in any given position, may be made from a scrap of 4 by 1 in. tin or zinc. One edge should have four or five sloping teeth filed on it. The other side is bent over about 1 in. and pinched or soldered on the hand rail just above the lever slot. The buffer plates are sections of 4 by 14 in. angle brass, 1 in. long, attached over the center of the bumper beam by means of small countersunk screws. The chains are of two sizes; the first, of small links, not over 1% in. long, for the uncoupling lever; the second, for the safety chains, with links almost 3% in. long. Sufficient chain of both kinds can LEVER-HOLDING RATCHET (1) UNCOUPLING LEVER | SHEET-METAL a Sato ) \ v A (o— “CHAINS Z WOODEN DRAWBARS — FIGS A pair of zinc-bound wooden couplers as installed under model railway cars be had from the dealers in model-makers’ supplies for a few cents. The safety chain at the left of each car (J, Fig. 1) consists of a staple, four links, and an open hook. The one on the right (K) consists only of a staple and a link that is somewhat elongated in shape. | Now, with the hook level, ascertain the vertical distance between the top of the rails and the bottom of the hooks. Maintain this distance as a constant in all future cars and locomotives. It will be convenient to make a wooden templet for testing this height. Attach the short piece of chain to the uncoupling lever, as in Fig. 1, making sure that the safety chain dangles outside the chain of the uncoupling lever. It will be convenient to provide a little hook, made of fine stiff wire, for hooking up the safety chains when the cars are coupled. A very fine buttonhook serves very well. Provide a place on the loco- motive for stowing this tool. In setting the main Miller hooks, leave a good 1/16 in. between the plane of the buffer plate and the plane of the back of the hook. This will allow % in. slack, which will be enough for all ordinary (Continued on page 133) © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. ‘it’s a Hohner ™ For nearly seventy years Hohner Harmon, icas have earned and deserved the re tation of being “The World’s Best.” are true in tone, accurate in pitch, fault less in construction and reasonable in price, The Hohner Harmonica is a real musical instrument, endorsed and recommended by leading authorities as a ‘‘stepping-stone to serious musicianship.” Hohner Harmonicas are the individual choice of amateur and professional play. ers everywhere. When you buy a har monica insist on a Hohner; and ask for the Free Instruction Book. Ifyour dealer isout of copies write M. Hohner, Inc., Dept. 182, New York City. ‘‘That Musical Pal of Mine” Tests Show Ford Can Run 41.4 Miles On Gallon of Gas The amazing fact that a Ford can run 41.4 mile on a gallon of gasoline was recently brought to light through tests con- ducted by America’s fore- most engineers. Great strides have already been made in this di- rection by the recent invention of a_ simple attachment which can be installed in a few minutes without any alterations to motor. A. C. Winter- burn made 41.4 miles on 1 gallon of gasoline after this device was attached. B. O. Weeks, famous aviator and _ in- ventor, wants agents and will send sample for trial. Write him today at 426-1452 Eleventh street, Milwaukee, Wisconsin. ZIP-ZIP LET’S GO BOYS No matter where you go, camping hunting, fishing, boating, to the country, the seashore or the mou tains, you will need a Zip- shooter. Thousands of boys are happy with this wonderful Zip-Zip shooter, If your dealer happens not to have them order them from us. ZIP-ZIP shooter complete only 35c or three for $1.00 pre- paid. Send stamps, coin or money order. AUTOMATIC RUBBER CO., Dept. 22, Columbia, $.6, moe — co hh © © © © 85 a y fred SS et Reh © += C2545 © tse ot eH OO OO = oO es - cof —-o =O © RR o& wet es ao ve 2x

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lealer isout Dept. 182,

un 41,4 mile y brought te

452 Eleventh

ZIP ) BOYS u go, camping ating, to the

Columbia, $.6,

ome Worlsslnosp |

| Couplers for Model Railroad (Continued from page 132) curves. In laying your track, try not to make any curves of shorter radius than et. : The first coat of paint should be merely a priming of white lead with plenty of oil in it. Allow this to become “bone dry” and very hard before applying the color coat. For the color you must choose your own, in accordance .with the prototype you have selected. The writer found “Pullman green” satisfactory. For the striping and lettering it is best to enlist the services of an expert. Nothing can more completely ruin an otherwise satisfactory model than a sloppy, amateurish job of lettering. HROUGHOUT this series of articles, much super-detail has been avoided. If you have been painstaking, you will now find yourself the owner and motor- man of a fast electric locomotive, one which should be capable of hauling from three to five cars at’fair speed. Because of the somewhat complicated motions of each car while entering or leaving curves, it might be a wise pre- caution to substitute plain flat brass for the angle brass that we have recom- mended for the’ buffer plates. If this substitution is made, it will give you an opportunity of bending the buffer plate to match the general curvature of the platform ends, as a whole. This sugges- tion is made now because for simplicity’s sake we have said nothing about placing equalizing springs behind the plates. The writer has found that 3/16-in. square steel rod makes a satisfactory and cheap track, but it must be drilled and countersunk for 34-in. brads at about 1-ft. intervals. At all points where the third rail crosses the running rails there must be a few inches of “‘dead” track. This is necessary to prevent a _ short circuit at the instant the pick-up shoe passes over the running rails. Such a dead track can be provided by inserting running rails of wood, of the same cross section as the steel rails, at the crossing point. About 3 in. will be long enough, but they must be located directly oppo- site the crossing point. The copper wire that runs along the top of the third rail need not in this case be interfered with. There will be no hesitation or irregularity in the motion of the locomotive at these dead points, because the locomotive has a pick-up shoe on each truck. Because of serious ill health, the writer is compelled to postpone for the time being all discussion of passenger car and Pullman model construction. This is, therefore, the last article of the present series, which began in the March issue. In all model work you will find that experience breeds skill. The farther you go, the greater your resourcefulness will become. Cultivate a placid frame of mind and you will find there is practically no limit to the things you can carry through to successful accomplishment. This, in addition to your own gratification, is the

great reward of a model engineer.

POPULAR SCIENCE MONTHLY Greater selectivity, range, power beauty ey ae lower cost!

BUILT LIKE—LOOKS LIKE—PERFORMS LIKE A $200 SET NOTICE! Enormous demand for the celebrated Miraco Ultra-5 ( its many enthusiastic users so highly recommending it to their je oe abled us to add hosts of costly new features, refinements and improvements such as you might expect to find only on the newest sets selling at higher prices. Mune) ~<G\or-s a Reports from oe... SPECIAL OFFER! GETS EM eearrebers (Oy-Noy leave little for CTheR fh [ N COAST See | owerlul New — M our files and which we receive a | IRACO Hears California to Europe Enclosed is a partial list of the stations I received with the Miraco Ultra-5: KSD, WEBH, WBAV, WEAF, WLW, WCBD, WHB, WOR, cea’ woc,

WCK, WHAZ, KFAB, WHAA, WAST, WCAB, WTAS. WOJ, (FIVE TUBE OUTFIT IN BEAUTIFUL MAHOGANY CASE] WOAI, WSOE, WCCO, KDKA; The amazing coast to coast re- ped with gold filled indicators for WBAP, WMC, CNRO, WIS, ception (on the loud speaker) and very fine tuning. That it is KHJ, WBZ, WMH, KFNF, international receiving range of even more selective, more powerful KFI, WEEI, WWL, WFAA, the famous Miraco Ultra-5 in the and is capable of getting greater

hands of its multitudes of pleased distances due to exclusive use users—as voluntarily reported by of ‘‘Duoformers”’ (ultra low-loss them to us in writing—offers proof inductance coils—the newest of performance which makes claims achievement i in radio engineering. .)

WCAE, WEAO, WRC, FFDM, WJJD, "WGR, WABN, WCAL, WEB, WHN, WMAQ, WJZ,

WLS, WOAW, Wwoo, WOS, by us superfluous. Send for ‘B”’ battery consumption is mini- CFAC, Sheffield, (Eng.): Paris plenty of this proof—and our re- mized and oscillations are con- (France). Carl H. au- markable Special Offer—at once! trolled on all wave-lengths by a kesha, Wisc. omer that nel apm new patented feature, the ‘‘Coun- - oldest and most reliable manu- ter-Balancer.”’ Flexibly wired (to Montana ae See to agp on of bentonite a a prevent et yg tg .) Has e y builds, thoroughly tests an an adjustment for different length Fives ‘ie - factory guarantees each Miraco. aetials, only two rheostats, a tra- ecelver. ave That longer experience and im- cut-out switch, concealed wiring

stations on my record in 20 days time om KDKA, WCAL, KFLE, WFC, WCC, WIAM,

mense production make possible and other features of costliest sets. such money-saving prices. Bear Comes in a handsome hand-rubbed in mind that this big, beautiful, mahogany cabinet. An instru- powerful and cleartoned Miraco ment thoroughly tested and ap- Ultra-5 is the latest, improved proved by radio’s highest authoritiesand model. That it has a beautifully | one_which apyone can easily connect,

AZ bee 9 WCCA sold — ge nuine Formica panel pay a log.”* Works on storage or ?,’ KFPU, KBB, KPO; with large Bakelite knobs equip- latest improvements —use coupon. KFAA ie Fe eos ErR § -_— Watnonveab ores. Rit: Il OtherMiracoLong D Sets Hy, WOS, WMC," WIJ; erM17vaco.Lo stance Se WGAN, KKU, WGW, WLW, OOI,’WHB, WFAI, WJAZ, Wonderfully improved new models in stations. All Miraco sets work on retail KGO, 'WCAF, KSAC, WTAP, Piistange Sets algo feady at lower peices lahat guimeritions ometahed velecal KSKI, KFKA. On February Powerful new Miraco R-3 at only $27. 35 Lat testimony of users convince you. 16th at 12:15 o’clock I received (retail) operates loud speaker on distaat Write tor literature and Special Offer. Ireland—the distance between seven thousand miles. Richard » Comertown, Montana. West Virginia Hears Australia Got 2-XB Wellington, Austraiia, plain last night at 12.45 A.M., over the Ultra-5 Miraco you sold me. I am delighted and would not trade for any in- strument in town. Geo. B Glen Ferris, West Va Gets Coast to Coast and Canada I received my Ultra-5 radio from you and I can say it is a wonder. We have received stations from coast to coast and also Canada. Orie E. ; Lacona, Iowa. All the Proof you want is waiting for You! Reports from their hosts of users In every state prove Miraco sets—at rock-bottom esate prices—outperform AGENTS, DEALERS sets costae much more mone Send for latest lit- Write for the new erature, SPECIAL OFFER and plenty of additional Mi - Mn cet festimony from users pe no doubt that *‘Miraco —— Radio Gets ’em Coast to Coast SEND COUPON FOR SPECIAL OFFER.

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MIDWEST RADIO CORPORATION nati, mt re Saeaeras. toate AL OF OFFER andall particulars "S50 ser = Send free iterates yhper() Dealer () AS NAME...-- eccccccocecess ADDRESS...cceoeserereree’® ereeereee posecocoeeoesss eee Ss eee

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YOU CAN BUILD THIS IDEAL —, WORK-BENCH — YOURSELF 4G Tie pleasure of working with tools at home is greatly increased if you have a strong substan- tial bench with a good vise. One that also has drawers and tool cabinets is a constant incentive to keep tools in order and give them the care and attention they deserve. A blueprint of the Home Workbench illus- = & =| Ba Nf ines Wy trated, with full size details and bill of materials Ff We eee =\\ PA ee may be obtained by sending 25 cents to — POPULAR SCIENCE MONTHLY 250 FOURTH AVENUE NEW YORK

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

Page 124

134 POPULAR SCIENCE MONTHLY Name Address 2'2 Tons Heats 5 Rooms! “There is no heater to compare with the Bulldog. I burned 2% tons of coal last winter and heated five rooms and bath.” —Walter Geary, Gloucester, Mass. That’s what the Bulldog does with coal! Here’s what it does with about the lowest grade fuel you can think of! “TI can run my Bulldog furnace steady for fourteen days in normal weather conditions on the actual cost of fifty cents.’’ writes F.R. Redetzke, of Cleveland, North Dakota, and he adds: “‘Hard to believe, is it? That’s what some of my neighbors thought until I showed them! We have an unlimited amount of grain screenings in this country. That’s the fuel I am using.” Comes Completely Erected! Fits Any Height of Basement Goes Through Any Door You Install It Yourself! If you are even thinking of a pipeless fur. nace, or any furnace, write for our free cata- log. The Bulldog is one furnace you MUST investigate. Comes completely erected, fits any height of basement, goes through any door, and you install it yourself! A really extraordinary development in heating. No Money Down! The Bulldog is sent you for free inspection, en, if satisfied, you make only small monthly payments, at our amazingly low rice! Factory connections in both East and est. We ship from nearest point. Don’t consider buying any furnace until you find out about the Bulldog. Write at once for our special cffer and our free catalog, together with pA ng record of Bulldog suce cess. Get ready for winter ! Mail thi coupon TODAY! as saeeeeee Babson Bros. saceeuese 19th & California Ave., Dept 13-67Chicago Without obligating me in any way please send me free catalog and & off on the Bulldog peless Furnace. Print name and address plainty, the fascinating and novel game illustrated. A stick 34 by 34 by 14 in. is screwed to a piece of sheet metal, which is fastened in turn to the wooden base, 34 by 10 by 10 in. A piece of spring brass 34 in. wide is bent and fastened to the top of the standard, as shown, to provide three places upon which a ring can catch. A \4-in. dowel 6 in. long is passed through the standard at right angles to the brass piece and about halfway between the top and bottom. The rings are made from 24-in. lengths of 14-in. stiff rope, the ends being clamped with thin metal pieces 1 by 21% in. : It will be noted that the number of points won by a successful pitch is de- termined by the position in which the ring lands. If it merely hooks on the dowel, no score is made,- but the player receives an extra try. At the end of nine innings, the player having the larger score is the winner.—D. W. C. Bus: luck and skill are required in “Tuck-o’-Ring” Is Novel Variation af a Familiar Children’s Game The players stand about 10 feet from the post and take turns pitching their rings. Three rings are colored red and three green Neat Fernery Built on Simple Lines O BUILD the simple yet attractive fernery illus- trated, obtain four pieces of hard wood 1 by 1 by 31 in. for the legs, one piece 1 by 1 by 40 in. for the long and short lower cross bars, and one piece 7% by 6 in. by 6 ft. for the sides and ends. This material must be free from knots and thoroughly sea- soned. The metal parts are five pieces of 14-in.-round iron rod 8 in. long, to support the earth box, and a sheet of SN)! TSS How the fernery is put together and meth- od of making the galvanized-iron lining _a thin coat of shellac, and two coats of galvanized iron approximate- ly 1714 by 34% in. In cutting the wood to the correct length, use a miter box as far as possible to in- sure square joints. Select the pieces with the prettiest grain for the sides and ends that are to be exposed, and sandpaper thoroughly all the surfaces that will be seen. With a %-in. bit, bore five holes 14 in. deep on the inside of the side pieces to form sockets for the iron rods, The center of these holes 54 in. from the lower edges. should be The assembly requires 22 dowels % by 1% in. Bore all the dowel holes, taking care not to center the holes in the legs so that one dowel will strike another. Put the parts together with hot glue by assembling first the long and short cross bars and then the two sides with the legs. On one of the assembled sides fasten the two ends; then add the assembled cross bar. Place the iron rods in their holes and add the remaining side. In making the earth box, scribe lines on the galvanized iron, as shown, cut out the piece and bend the four tabs marked A at right angles over a straight-edge. The four tabs marked B should be rolled right over and drawn down tight against the side so as to make a neat rolled edge for the top of the lining. The sides and ends then are bent up with the tabs A inside, and the joints are soldered. The finishing may be done in any preferred way. A coat of stain, fixed with spar varnish is a desirable finish.—FRED E. Fox. an maid. en ao © This seal on a radio or too! advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6

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CS oximate- »d to the a miter le to in- elect the prettiest ind ends sed, and y all the > seen. it, bore p on the rieces to ron rods, se holes > edges. wels 34 el holes, es in the another. t glue by ort cross the legs. isten the led cross eir holes : lines on t out the arked A ge. The led right ‘inst the edge for des and tabs A ed. in any xed with coats of .—FRED + POPULAR SCIENCE MONTHLY EEP your tools _- well shaped and sharp. When a tool gets dull, stop and grind it. Some men waste a lot of time talking about the imper- fections of their tools and ma- chines; they will ‘alate a et ahead faster ul, machine - - (ea put more shop foreman thought and energy into the actual doing of the task in hand. Mill files often will work smoother when rubbed with chalk on both sides after cleaning. An exceptionally good workman al- ways seems to have an exceptionally good job. A leather belt always should be run with the hair or grain side toward the pulley; the belt is less apt to crack, will last longer, and will transmit more power. A medium soft wheel is best for sharpening a milling cutter. Never bite off too much at one time —go slowly but surely. Being slow and sure is different from just being slow. No horseplay in the shop! Too many men have been made cripples by play- ing around the machines. It sounds better to hear a man say “TI did’ than “‘I’m going to.”’ How to Drill Small Bushings, Pulleys, and Gear Blanks [N MAKING bushings, pulleys, and gear blanks from iron, brass, or bronze castings, nothing is to be gained by having the hole cored if its diameter is 1 in. or less. The more satisfactory way is to have the castings made solid. A drill will cut cleanly through the solid metal without as fre- °F quent regrinding seals as if it were biting into a rough, cored opening. al | Short bushings > whe || “5 with small holes a Sag ean be held in a Sim SS lathe chuck bolted 7 to the table of a BRILL PRESS drill press and drilled and reamed fe esentt sagtig more rapidly than in a lathe. (Continued on page 136) LATHE CHUCK c ar Balkite Trickle ; ; *T etteneen Charger . s Balkite Battery Charger Balkite Radio Power Units the ideal radio power supply The Balkite Battery Charger and Balkite Trickle Charger for charging “A” batteries —entirely noiseless. Balkite “B” replaces “B” batteries—for sets of 5 tubes or less, Balkite “B” II—for sets of 6 tubes or more. FANSTEEL PRODUCTS CO., Inc., North Chicago, Ill, FAN STEEL ,. m di Balkite a Units C BALKITE BATTERY CHARGER - BALKITE TRICKLE CHARGER - BALKITE“B” - BALKITE“B"2 2 AGNATRONS have achieved leadership in the vacuum tube field, but the constant vigilance which has brought these tubes to the fore has not for one moment been less- ened. Every part, from contacts to filament, is tested, constantly tested. The Magnatron DC-201A, DC-199, and DC-199 (large base) now list for only $2.50 each. Connewey Electric Laboratories Magnatron Bidz. . Hoboken, N. J. MAGNATRO = ~~ ve © This seal on a radio or tool advertisement signifies the approval of ‘the INSTITUTE OF STANDARDS. See page 6.

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ap ig radio engineers agree that an enameled aerial is su- perior to a bare copper aerial, because the rapid corrosion of the bare copper wire, exposed to atmospheric fumes and smoke, quicklyreducesthe aerialefficiency. Use a Beldenamel Aerial, because every strand is coated with baked Beldenamel to keep the wire bright and shiny. You do not have to clean a Beldenamel Aerial. The Beldenamel coating is not affected by moisture or atmospheric fumes. It lasts indefinitely. Try a Belden- amel Aerial, and hear the differ- ence. pen for Free Illustrated cas Belden Manufacturing Company, 2304-E So. Western Ave., Chicago. Please send me your latest illustrated booklet, free, describing Belden Radia Products and their use in radio work. POPULAR SCIENCE MONTHLY | MILLING MACHINE FN (U etch success in set building. Gives | advanced hook-ups. Shows i, all newest. parts and kits 4 at prices far below others. 4 ra me Build the newest @ more money. 102-122 $. Canal St., chicago | Milling iachdaw Used for Cutting an Ellipse | rnin nee grea having to machine el- liptical holes may avoid the tedious and difficult task of filing to a line after drilling out the core if they have access to a vertical milling-machine attachment. By using the method illustrated a perfect ellipse may be generated. The die blank is held in a vise or on an angle plate, as convenient. A boring-tool is held in the attachment in the usual way. For ordinary work the angular setting of the attachment may be found by lay- ing out the work on paper and measuring the angle with a draftsman’s protractor. If A is the minor axis of the ellipse and B the major axis, lay off a right triangle with A as the base and B the hypotenuse. ATTACHMENT ON MILLENG - MACHINE k— A—+ Milling machine set to cut anellipse, and how to find the correct angle by means of a diagram The angle C between these sides is the angle to which to set the attachment. The angle may be computed for more accurate work. The cosine of an angle is equal to the side adjacent to the angle divided by the hypotenuse. In the illus- tration, A is the side adjacent, and B the hypotenuse. Assuming that these are 4 and 6 in. respectively, then the cosine of the angle C is four divided by six, or .666. Referring to a table of natural sines and cosines to be found in any machinist’s handbook, the cosine .666 is found to be- long to the angle 48 deg. 46 min. This represents very accurately what the angu- lar setting of the attachment must be. How to Drill Small Bushings (Continued from page 135) Then they are finish-turned on an arbor between centers in the usual way. When it is desired to machine bushings in this way, a center can be cast in one end for starting the drill, as illustrated. This saves laying out the center. All that is necessary is to chuck the work as pre- viously suggested and bring the drill to bear in the center of the casting. A COMPOUND of ten parts tallow to one part mercury is a dependable help in keeping tools from rusting. —Writes Peter Werner, 1 Sell Madison “B eters nat Shirts for Large Manufacturer Direct to wearer. No capital or experience needed. Many earn $100.00 weekly and bonus, Write for Free Samples MADISON SHIRT M’FRS, 595 Broadway, New York e Agents €roduce MELONGER ogo TIRES Jakiscut, Ss | 15,000 %, Lowest pedis oom oy Prices in ype 8 fica. Shipped pone on approval. Make \ big money allorparttime. No poniaiet wn experience. Sample sections furnished. FOUR TIRES GIVEN iy send name today for FREE ey tel on cusands do bie Bee wok ae 1 Ag holesale Sampie Kit. PELLINGER TIRE “& RUBBER co, I 4 ) Harle ¥ I: a h Side PUA Wa : eti f iy ‘tr wr AMERICAN MOTOR CYCLE Co. 2047 W. Chicago Ave., Dept. 1034 Chicago CLASS 25¢FING a DIRECT FROM Ape. MAKER SICATALOG FREE ete ither pin shown made with any 3 letters amd = igures 1 or 2 colors enamel. Silver plate 25 ! ‘ea. $2.50 doz. Sterling silver. 40¢ ea.. $4 BASTIAN BROS, CO. 631 Bastian Biog., Rochester, N. Y. pied aggressive, Mr. Brush Salesman j:::;.:.2e8 tling men to represent an old established mz ae ae high grade, guaranteed, fastest selling line of Sanitary Twisted in Wire Brushes, sold direct to the Home. We have openings for experienced brush men as ma 8 in all territories. We want live wire, energetic Ge. Getters. We pay larger commissions than any other Brush House in the Country. If you want to earn some real money, it will pay you to write us immediately for our proposition. WIRE GRIP SANITARY BRUSH CORP., 15 Mercer Street, New York City. 3490 Unusual 9} tunity is of on “AFTER TEN DAYS TRIAL ‘FOR THIS LONG WEA ‘Bésianc.C.SD E— Test ae onder ul t; Bewnter i in your home or offi If you are not pane Ae it ‘is the beet Jn yyouever mada whee your$3d deposit a OQWEST PRICES ever made on the world famous L. C. Smith — full size—all late style ope rete conveniences—absolutely high ' quality rebuilt —5 Year Guaran- mall Monthly Payments. FREE: Course of Instruction, Tools, Waterproof Cover, all free to you now. Send today for New Special Offer and Booklet of valu- able typewriter information. we Smith Ty ype ewriter Sales Corp. 321-360 DEAFNESS IS MISERY GOOD HEARING A JOY Millions of people know that, but Multitudes of persons with defective hearing and Head Noises are again enjoying conversation, go to Theatre and Church because they use Leonard Invisible Anti> septic Ear Drums, which are Tiny Megaphones fittingin the Ear entirely out ofsight. No wires, 00 . batteries, no head piece. They are Unseen Comforts and inexpensive. Write for booklet and sworn statement of the inventor who was himself deaf. A. O. LEONARD, Inc., Suite 144, 70 5th Ave., New York © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. Grand Av., Chicagog J mm ort ct DOO

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tober, 1935, 4h Ours) ‘erner, tter= Pe anufac (0 capital M pital or usual o lity is offered r ag gressive, bitious, hus anufacturer of ie of Sanitary ie Home. We Las ma energetic Go an any other . to earn some imediately for .RY BRUSH ty. , JOY Multitudes of Head Noises > Theatre and visible Anti- Megaphones No wires, n0 een Comforts t and sworn himself deaf. ».» New York Moder Snap Mletinods Scales Fixed to Steam Hammer Save Blacksmiths’ Time LAC K - B SMITHS |. who forge large work under the steam hammer will find that a scale attached to ] the hammer will | save them much | © of the time they otherwise would spend in caliper- ing their work. The illustration shows two scales, one of which is visible from the front and the other from the side. When the dies are planed, the indicator point is reset.—ALEX C. FABRIS. Scales on hammer Rubber Hose Used as Safety Holder for Chisel ANY a workman has suffered severe injuries to his hand when his ham- mer glanced from the head of a chisel or punch that he was holding. In order to eliminate this risk, the service supervisor in a large concern in the State of Wash- This safety chisel holder is made of a short length of hose and two pieces of wood of discarded air hose. He cut a slot about 114 in. from the end of the hose to take the chisel or punch and drove a piece of wood into each end to retain the tool firmly in position. With the aid of this holder it is an easy matter to direct the tool accurately.— GEORGE F. PAUL. Tracing Paper and Cloth Held Flat with a Wooden Fork [ARGE sheets of tracing paper, cloth, or thin drawing paper, very often do not lie flat on the drafting table, particu- larly on and after damp days. Under these conditions the sheet can be held down as shown, by means of a fork- shaped piece of wood.—A. E. Z. ington made a safety holder from a piece © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6, POPULAR SCIENCE MONTHLY AMSCO ANNOUNCES A SPACE - SAVING S.L.F. CONDENSER Solved ! The space problem of the straight-line frequency condenser. The new AMSCO Allocating Conden- ser is ingeniously designedto save room in the cabinet, yet spreads the stations evenly around the dial, according to frequency. Greatly improves the se- lectivity of the set, and simplifies tun- ing. Three sizes, Single or Siamese. Ask your dealer or write Dept. G AMSCO PRODUCTS, INC. Broome and Lafayette Streets, New York City MAKERS : MELCO SUPREME RADIO RECEIVERS Half a Heart is the Half a Heart is the secret. Half a new symbol for effi- Heart is the shape cient S. L. F. varie of the rotor plates. able condensers. Make More Money ovesssties sn asses ius to 174 of this issue. im Get Boice Prices Before You Buy! Now As the world’s largest builders of small_bench machines, Boice offers greater values at lower prices with a positive money-back guarantee, Whatever you build, there’s a Boice-Crane bench machine to do your work. Circular saws, Band saws, Lathes, Jointere und Drills. Write for literature, prices and the Bboice E-Z Pay Pian before you buy. 8 Inch Bench Lathe Junior Saw d and soft metal. Swings 8-in. maximum over bed. A speedy accurate machine of all-metal construction. Table benesie vii, between centers. Headstock integral with 10-in. x 13-in. Saws 1 1-2-in, stock; dadoes 5-8-in. x 5-8-in.; heavy cast-iron bed. 3-sten cone pulley tor 1-in. flat belt for driven by any 1-4 to 1-2 H. P. motor. Portable. Attaches te moter or counter-shaft drive, Replaceable bronze bearings. light socket. Table iistock have No. 1 Morse taper. 3-8-in, hole % Headstock and tailst thru headstock spindle. Feige eo Jan be fitted with jig for grooving saw. circular saw and sanding grindin: ~ sand disc attachments, and drilling Sol: gins sere oaen a with or without in, Jacob’s chuck an arbor for emery or motor and base. buffing wheels, W.B. & J. E. BOICE Dep’t. P.S.10-A Toledo, Ohio ©

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138 POPULAR SCIENCE MONTHLY Lo YK At Z + = aes 47 = = ar S = a A Handy Sewing and Work-Table =r Easily Made at Home Every woman would like this table that combines the convenience of the ordinary sewing table with a large flat top for spreading out her work. Any man who uses tools can easily build this simple combined sewing and work-table from blueprints, which we will supply for 25c. The blueprint includes a list of the ma- terial, size and quantity of each item required for the handy table. PopuLaR ScIENCE MONTHLY 250 Fourth Avenue New York * “1 Easy toDraw Cartoons When Shown in the RIGHT WAY Some of the cleverest cartoonists and comic artists learned how to draw in their spare time by following Cartoonist Evans’ Simple and Easy to Learn Method and are now MAKING GOOD MONEY. Send one of your drawings, and let Mr. Evans see it you have ability and receive the Portfolio of Cartoons and full details about the course. It is not expensive. THE W. L. EVANS SCHOOL OF CARTOONING &25 ‘Leader Bullding Cleveland, Ohio “DON'T SHOUT” “*T hear you. I can hear now as well as any body. ‘HOW?! With THE MORLEY I've a pair in my ears now, but they are invisible. I would not know Ihad them in, myself, only hat I hear all right.” The Morley Phone for the is to the ears what glasses are to the eyes. Invisible, , ms pomp enn yom fess and harmiess. Anyone can adjust ft. er one and sold. Write for booklet wall puotimoulale: amend THE MORLEY CO., Dept. 797, 10S. 18th Street, Philadelphi Stop Using a Truss STUART’S PLAPAO-= PADS are different from the truss, being mechanico- chemico applicators made self-adhesive purposely to hold the distended muscles securely in_ place. No straps, buckles or spring attached—cannot slip, so cannot chafe or press against the pubic bone. Thousands have success- Reduced fully treated themselves at Fac-Simile — eo yor ee mea rom work—most obstinate Gold Medal cases conquered. Soft as Grand Prix velvet—easy to apply—inexpensive. Awarded Gold Medal and Grand Prix. Process of recovery is natural, so afterwards no further use for trusses. We _ prove it by sending Trial of Plapao absolutely FREE Write name on Coupon and send TODAY. Plapao Co., 790 Stuart Bldg., St. Louis, Mo. Return mail will bring Free Trial Plapao BLANK CARTRIDGE PISTOL Sia PRICES tection against Burglars, Tramps, & Dogs Well made and ef- fective; modelled on latest type of Revolver; appearance alone is enough to scare aburglar. Whenloaded it may beas lakh Length closed 3% in. This clear, accurate, powerful 6 Power Pocket Telescope (Genuine Wollensak) $ Postpaid with 2 limp leather case Made by one of the finest lens makers in the world. Guaranteed by both this company and the maker. No bigger’n a jack-knife, easily carried in vest pocket yet a_ powerful, precise monocular, that brings distant objects close, in full detail without the ‘vibration’ present in higher power telescopes. Adjusts twice as quickly as binoculars. Nothing cheap in appearance or construction. Black baked-in enamel with non-slip grip. Soft leather case with glove snap included. $2 prepaid. Money back if ndt thoroughly satisfied. BOSTON SPORTING GOODS CO. Dept. Q, 80 Boylston St., Boston, Mass. Smith & Co., Dept. 418 Racine, Wis. NATIONAL SPORTSMAN isa monthly magazine cram- med full o: hunting, fishing, camping and trapping stories and pictures, valu- able information about guns, revolvers, fishing tackle, game law changes, best places to get fish and game, etc. Biggest value ever offer- in a sporting magazine. And here’s a knife that every man and boy should own. Has a sturdy master blade } of good full size and extra gauge of ashape especially useful for hunters, trap- pers, campers. and fishermen. and a punch blade which can be used for a multiplicity of purposes. This inches long, with 18 per cent Both for NATIONAL ° SPORTSMAN sters and shield ia of sol d construction throughout and has a good full handle to fit the grip of a large or evenover-sizedhand, The na ingt blade is your guar- antee of quality. M4 « We will send this knife and Nationa Special Offer: Sportsman for 6 months on receipt of $1 National Sportsman Magazine, 255 Newbury St., Boston, Mass & This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS, See page 6. Detter Shop Meter Simple Ways to Gage Heat of Small Shop Furnaces While letters from readers in remot | parts of the world are received fre. | quently by POPULAR SCIENCE MONTHLy | it is not often that a contribution j, submitted by a foreigner in such Clearly written English that it can be useg practically without editing. This wag true, however, in the case of an article written by L. Israilevich of Leningrad, Russia. It was accompanied by a lette, in which he said: A few days ago I happened to read a few issues of your magazine and I just-took to it, if there is such an expression in English. [| am a constant reader of various other popu. lar magazines, but your magazine seems to strike a different note, which is somehow mighty pleasing to me. Well, I am sending along a short article for the Workshop Department. The idea, though not exactly new, is carried out with such simple means that the method is quite suitable for small shops, garages, etc. Mr. Israilevich’s article is as follows; ESTING the heat of tool carbon steel in a furnace is done in most small shops by the eye. This requires a lot of experience and, being founded on gub- jective perceptions only, leads often to costly mistakes through overheating, FURNACE HEATED TO A MAXIMUM ville re NERS SSN NN NN NYS WN SS MAGNET Salt used to show overheating and a magnetic tester to indicate the correct quenching heat By the use of a few simple devices, it may be made possible, however, to determine easily and certainly the required degree of heating. The method consists essentially of so heating the steel that its temperature never exceeds nor is lower than certain temperature limits. To prevent overheating, the tempera- ture within the furnace should not exceed 1470° F. This is accomplished easily by placing a porcelain dish with common salt into the furnace and adjusting the heat every time the salt begins to melt, which it does about this temperature. For the lower limit we can make use of the property of steel to lose its magnetic qualities when heated to its proper quenching temperature. Carbon steels used for most machine-shop tools—screw taps, milling cutters, dies, etc.—have this property in full measure. This can be said generally of most kinds of carbon steel containing from .9 to 1.4 per cent of carbon. As to steel with .7 to .9 per cent (Continued on page 139) tel anaes em wee oe oe _—»— gh ont Gute & oh = 2 tit

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: Heat aces in TemMote e1ved fre. MONTHLy ibution jg ich Clearly 2 be useg an article eningrad, by a letter ead a few took to it, nglish. [| her popu- : seems to somehow article for the idea, out with d is quite tc. is follows: arbon steel most small res a lot of don sub ls often to

a magnetic ching heat ices, it may » determine od. degree of tially of so emperature han certain e tempera- not exceed d easily by ommon salt ig the heat melt, which make use of ts magnetic its proper tbon steels 0ols—screw —have this his can be of carbon per cent of .9 per cent

Ways to Gage Furnace Heat (Continued from page 138)

of carbon, certain restrictions should be applied, for below .9 per cent there is a temperature range when steel _loses its magnetic properties before attaining the correct quenching heat. This restriction js practically of small importance, how- ever, and can be corrected by heating for a little longer time. To determine the moment steel loses its magnetic properties, a magnet in the form of a balance must be constructed. If pieces are brought to it during the heat- ing process, the moment of cessation of its being set oscillating by this action will fix the proper quenching heat. It gen- erally is better not to bring the piece to the balance, but to put it the other way

Another magnet balance for determining the correct temperature for hardening steel in the way described by Mr. Israilevich. This device was made by William J. Edmonds, Jr., of Whitehall, N. Y., for emergency use when a regular pyrometer was not available around, because in the first case the piece has a chance to get considerably cooler before it is plunged into the quenching bath. Of course, this may be offset by heating the piece to a little higher temperature, which is quite safe. The magnet may be made of an old le. Care must be taken to saw the ends off squarely and not in an arc, as in the latter case the lines of force disperse and the magnet becomes somewhat weaker. A convenient way of mounting it is shown in the accompanying drawing (on the preceding page). The attraction be- tween the magnet and its iron mounting will cause it to retain the position shown. Sometimes, when the magnet cannot be employed directly, as when a portion of the piece is heated, a trick may be re- sorted to. It consists of heating along with the main piece another smaller piece of steel of the same composition and determining by it the temperature of the main piece.

Remedying Loose Pipe Joints with Brass Wire Cloth HEN threads are cut in a lathe on pipes that are 2% in. or more in diameter, it sornetimes happens that the correct diameter is not obtained and the fitting will screw on loosely, right up to the shoulder. The joint can be made tight by wrapping around the threads a length of brass wire cloth of from 60 to 80 mesh. This should be daubed freely with litharge or red lead.—F. N. C.

|

POPULAR SCIENCE MONTHLY ~jimplions

ARS y Ay '. His Holiness the Pope seated “on his throne upon the occa-

sion of the recent canonization of Sister Teresa. The microphone is on the right arm of the throne. Of ALL loud speakers, Amplions enjoy the honor and high compliment of having been installed throughout the famous Cathedral of Saint Peters, Rome, that important ceremonies conducted by His Holiness the Pope may be clearly audible to great multitudes of people. Supreme clarity of reproduction was the prime requisite. It is only logical that The Amplion —creation of the actual originators and oldest makers of loud speakers—should have been chosen. Amplions outsell any other loud speaker throughout the world, chiefly because of unrivaled clarity of tone. “The clearness of the reproduction of the Pope’s voice was an outstanding feature,” writes a witness to the first ceremonies. Hear The Amplion in comparison with any or all other reproducers. Prove to your entire satisfaction that it is the ‘world’s finest loud speaker’. Amplion Loud Speakers, $12.00 up. Phonograph units in two sizes. Write for inter- esting literature and dealer’s address. THE AMPLION CORPORATION OF AMERICA Executive Offices: Suite M, 280 Madison Ave., New York City Canadian Distributors: Burndept of Canada, Ltd., Toronto Alfred Graham & Co., London, Eng., Patentees *AMPLION She Worlds Standard foud Speaker

139 chosen & reproduce \ °Papal Ceremonies A portion of the magnificent canopy over Saint Peter’s Tomb, showing two 2 saved Amplions installed for amplifying Papal services to vast assemblages of pilgrims.

SEND NO MONEY 2 Genuine Diamonds 4 / 100 Each Cut Stones, No Chips Solid Gold Spe. |// YZ =—" $25 Terms if desired (6 mos. to Pay) Outside U. S. cash with order 14 kt. White Gold Top. Gold Emblem (any Lodge) or any Initial (Old English) Yellow or White Gold, i Genuine HOPE RUBY \} _ Also, in Black Onyx ia New 61: Scnbeiseat Angszendisine This Rea. Trade Mark Send for Free Cat: A ae DFCMSYW Ay Buffalo Jewelry Mfg. Co., “The Mail Order House” Dept. A 501 Washington St. Buffalo, N. Y.

inlaid in

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS, See page 6. NEW VEST POCKET ADDING MACHINE ADDS - SUBTRACTS Q5 = | MULTIPLIES - DIVIDES 3 —=- | Does all the work of a $300.00 machine, eee x yet fits the vest pocket. Easy to operate —does any kind of figuring inajiffy. The © - neatest and best constructed portable adding machine made. Counts Clear Up to 999,999,999 Total visible at all times. A pull of the finger clears it. Invaluable to anyone who uses figures. | its cost by preventing mistakes. Saves many times 10 Days’ Trial Semon; \ address and we will send machine t= iW paid. Pay postman on delivery $2.96. se it 10 days to prove it does all we claim. Your M money backif not perfectly satisfied.Don’t be fooled by cheap imitations. your Ve-Po-Ad now from this a Reliable Adding Machine Corp., Dept. 157 cen! ia "shia 84 W. Washington St., Ch Here's a money maker. ery lendid profit. Write for , wants offer.

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140 Sent On Approval We will send this famous watch direct to you, express prepaid on FREE approval. Examine watch and be convinced it’s the best watch buy you ever saw. You save 1-3 to 1-2 your money by purchasing a Santa Fe Special Watch. We trust you—Wear watch while paying for it. SEND FOR FREE WATCH BOOK Clip the coupon, fill out and receive the FREE WATCH BOOK. All the newest watch case de- signs in white or green gold, fancy shapes and thin models are shown. Read our easy payment offer. Select the watch you would a to see, we will send it to you _on approval, express prepaid. Wear the watch 30 days FREE—return at our expense if not fully satisfied Ask for Santa Fe Ladies’ Bracelet Watch folder and Diamond folder. SANTA FE WATCH CO. Dept: A-80 Thomas Bldg., Topeka, Kan, The Home of the Great Santa Fe Railway, BEE ae eeey Santa Fe Watch Co. ee. Dept. A-80 Thomas Building. Topeka, Kansas. Please send prepaid and without obligation, be your Watch Book Free, explaining your ‘“‘No + we Down" Offer on the Santa Fe Special Watch g he nen cies ei ara nian eTTTYIriiiritiiia Learn. Furcraft we up New Furs and Make Old Furs Like New. iring and Cleaning. ing, ironing and sto. ‘need in every neigh' derfal uncrowded f big $3 a by mail, evenings at home _ Learn Fur Ree our secret processes. Learn glaze . Big demand, rhood. A won- eld. ——e ad ANY H AR Ho u r iN pl SPARE TIME a or a real business now and later a oat fur shop. Next month earnings start if arn now. Men and women a8 soccessful. ~ Tells all about this Dy. Free Book ress of curity POPULAR SCIENCE MONTHLY arenes and Die , Shakes (Continued from page 74) Next, grind and blue one side of the punch. Lay this side on the cutting edge of the die and scribe the outline on the punch. Clamp the punch on the lathe faceplate and bore out the four l-in. holes, as in Fig. 9, truing up the center punch mark in each ease, as for the die. Then cut the stock away either with a metal-cutting bandsaw or a power hacksaw. In shaping the punch, try to work within .005 in. of the line all the way around. It will pay you to spend time in accomplishing this, because it is much faster than filing. If properly done you need not touch the work with a file. You now are ready to shear the punch in the die. If you have left .605 in. all the way around and the die is sharp, hard, and of uniform clearance, you should have no trouble in shearing the punch through. Make sure that the punch is going in square and the chips are not choking the die. Use lard oil and patience. Remove the punch and file more stock off if necessary, rather than run the risk of breaking the die. An arbor press is a good tool for this job. To file the clearance on the punch, grind one end of a parallel round file back a distance equal to the thickness of the punch pad, making the diameter less by the amount of clearance. In this case the difference is .125 divided by 20, or nearly .007. The thickness of the soft steel divided by 20 equals the clear- ance. File this clearance on the drill press, as shown in Fig. 7. The file will cut until the ground part touches the punch. fier punch is hardened and tempered and the back part drawn to a blue in a lead pot, if one is available, because it must be riveted over in the punch pad, as shown in Fig. 8. Riveting is illustrat- ed here because it is the method a machinist most frequently encounters. Bevel the opening in the pad to suit the headed-over portion in the back of the punch. The punch must be a good fit in the pad and stand square. Place the punch in the pad, grip thé punch in a shaper vise, see that the pad rests on top of the vise, and rivet the punch over until it fills the bevel in the pad. Grind the punch and pad together until they are flush. Then machine the stripper until the stock steel slides through easily and assemble. When the shop equipment is limited and there is perhaps only a lathe, shaper, and drill press available, the task is some- what harder. After the parts are ma- chined and bored in the lathe, as in Fig. 4, the core must be removed by drilling. Lay out the die as in Fig. 10, using the layout tool shown, which scribes a circle and also makes a slight center punch mark, which can be enlarged if desired. After the holes are drilled, you have a jig for spotting the layout on the punch pad, stripper, and shoe. After these are (Continued on page 141) Relieve the Pain, Prevent Infection Use Absorbine, Jr. ‘the magic bottle’ to heal’ cuts, bruises, burns, rash, skin eruptions and to reduce swelling. It’s a a. powerful and effective antiseptic liniment. $1.25 2 bottle at your druggist’s W.F.YOUNG, Inc., Springfield,Mass. Whether it is in the Kitchen, |i Office, Studio, School Room or Factory. We can supply you with the reliable, well made and guaranteed H awkeye Remind- er Clock that is ‘watchful of the time.” Easily set to one, three or ninety minutes and rings Exactly on the minute when time is up. Prevents Forgetting, and thereby saves Time, mind and money. Handy si gray enamel finish, hangs flat against ui or sets on table. Reasonable price. HAWKEYE CLOCK COMPANY Muscatine, Distributors Wanted INSTRUMENTS! WORLD'S LARGEST MANUFACTURERS . E ASIER playing qualities of Conn instruments, the result of exclusive Conn Proce esses, speed your progress, give you quickly the pleasure and profit of. personally played music! Used and endorsed by the world’s greatest artists. FREE TRIAL: 2? mentsonanyinstrument forbandor orchestra. Send today for catalogs and details; mention instrument, Cc. G. CONN, Ltd. | 1013Conn Bidg., Elkhart, Ind, ROBERT E. CLARK Trombone Soloist \\ U.S. Marine Band \, uses a Conn, EXAMINE. FREE ‘Startling Cash\ This querentent 3/41ess 1/16 ct. gene Fora iamond at a low pricenone can beat—$68.50. Asolitaire of bi iancy in handsomering. bo en loan value f: Market Price. This¢ or any of Res A of equally big diamond bargains sent for absolutely free examination at our risk, A Fraction of; Latest List— blazing Market Prices pace Bhs This 75 zone, caer at, larecet, for as $60 Det rated over $ rat li, some o! ca mond Banki + y aye in all the world lends money on dia- | prices monds. Thousands of unpaid | m ' Loans and other bargains. | an’ fi complete bi with European yx n oS | exact weight, color, iia et cutters. Mus Ow. free. e. yodes ROY & "SONS, 4737 Opposite Post Office he Paes bone ire By Mail 8 ‘ 5a Tawyet A business: ae Qualify -. — Ay 00 te 0.06 a a year met TUF wes SEASY TERM Bractieat Vand a a utheritat ve: non-resident cours course. PERSONAL IN. INSTRUCTION. Ly 4 aduate failing to ease bar exams. aoe. REDUCED ITION pty now in force. Write today for particulars and book on law FREE. AMERICAN CORRESPONDENCE SCHOOL oF LAW Dept. 1367 3601 Michigan Avenue, CHICAGO fun irnishe Sve or 60. raed by ben ~~ TA tee to coach free an Begin ‘Today— Write for my FREE BOOK, Ica a good penman of ‘ou at home during spalt time. Write formy FREE BOOK, ‘‘How to oils d Penm * It contains specimens and how others meatevedl penmanship by the Tambint System. Your name will be elegantly written is ant) Af Evol ee stamp to pay postage. Write IF. W. TAMBLYN, 437 Ridge Bldg., Kansas City, U.S. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6 dril the ten sho Th pos grit rad too whi the ius, ate sug tio ang met the

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@ or ninety inute when nd thereby Tandy size, inst wall or ANY Towa, NIN T MANUFACTURES 1g qualities of instruments, ye Conn proce progress, give oleasure and layed music yy the world’s Easy ant for baador y for catalogs 1 instrument, |, Ltd. Elkhart, Ind, oo remeron 1/16 ct. gen- ice none can f big blazing zy. Has guar- fraction of hundreds of ins sent for | atour List— Loans DOL OF LAW SHICAGO -E BOOK, I cat ome during spare How to Become ecimens and tell by the Tamblya fen Sno Mietinods| prilling n Emery Wheel with a Brass Rod “(XOULD you drill a hole in an emery C wheel with a brass rod?” a tool- maker asked me the other day. I told him that I did not believe it possible. He took a short length of 14-in. rod, filed it as shown, put it in a drill press ” at high speed, al V4 DIA. and drilled a hole through an old emery wheel about in. thick in almost no time. He did the same stunt with cold-rolled steel, and even a wire nail may be used.—S. L. ROBERTS. Punch and Die Making (Continued from page 140) drilled, remove the core by cutting away the bridge with the broach shown in Fig. 10. Then scribe the outline of the templet on the punch pad, stripper, and shoe. These now are ready to be filed. ‘The lines should be split as nearly as possible on the die and punch pad, but the stripper and shoe should be a trifle larger for clearance. The filing can be done with assurance by a mechanic who has had little experi- ence in this class of work by the method illustrated in Fig. 11. A hardened and ground parallel strip and a piece of hard- ened drill rod, both of which have the \y-deg. taper, as shown in Fig. 11, are required. These file guards are placed so that they split the scribed outline on the die. They are made fast with a few drops of solder. An old saw blade is used as a safety guard, as indicated, to prevent the file edge from touching a part already finished. The four parts are finished in this manner and the punch is made as pre- viously described. OF DRILL : EMERY WHEEL TABLE Piercing a hard grinding wheel Grinding a Radius Larger than the Wheel Available ANY one who has tried to grind an accurate radius forming tool when the wheel available was smaller than the required rad- ius, will appreci- ate the method suggested in the accompanying illustra- tion. By tilting the grinder table to an angle that is found by the cut-and-try method and grinding on the edge of the the wheel as shown, I have ground tools to a templet with sufficient accuracy to ‘pass an inspector.—K.C. 6'RADIUS ' Among the articles scheduled for forthcoming issues are ‘The Shipshape Toolroom,” ‘‘Methods of Repairing Gears,’’ and “An Improved Combina- tion Boring-Tool.” ———— POPULAR SCIENCE MONTHLY 141 * / a ' Partners for Power | If you want distance and clear tone from your radio set, your storage battery must have its partner—the Tungar Battery Charger. ee — Two clips and a plug to connect to the house current. That’s ali there is to it. Or you can make permanent connection and just throw a The Tungar is a G-E switch. product developed in the great Research Labora- foriesofGeneralElectric. 2 ne Tungar charges while you sleep—it makes no disturbing noise—keeps your batteries at top notch. For power there is nothing like a good storage battery—with a Tungar to keep it good. Thenew Tungarcharges 2, 4, 6 volt “A” batteries; 24to 96 volt “B” batteries, in series; and auto bat- teries, too. No extra at- tachments needed. Two ampere size (East \ of the Rockies) . $18.00 60 cycles—110 volts REG. U. S. “ PAT. OFF. fa © [BATTERY CHARGER \ Tungar—a registered trademark—is found only A on the genuine. Look for it on the name plate. Merchandise Division .. General Electric Company, Bridgeport, Conn. GENERAL ELECTRIC WANTED gg RAILWAY POSTAL CLERKS ------>=== so $1900 to $2700 Year | oc temer H Dept. G-276, Rochester, N. Y. City Carriers—Postoffice Clerks . Sirs: Send me without charge, (1) Specimen ‘ ] Railway Postal Clerk Examination questions; z (2) Schedule showing places of coming U. S. Postal Salaries Just Raised 2 Government examinations; (3) Free sample coach- TRAVEL—See your country Fy ing. MEN—BOYS, 18 UP r I n- SHOULD MAIL COUPON IMMEDIATELY I PNGNEG So: 0: 6:5:.0:5.0i6:ebnessicielverenaied oie sameeren Steady work. No layoffs. ! Paid Vacations. | Pididpeaitiei 5. 25 6:05 de Estates cee nite sa tease en © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

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; | | | | } } ; | : 142 An old-timer sets a quantity pace for pipe-smokers Here is a remarkable letter from an old- time traveling man in Seattle who says he has smoked five-eighths of a ton of Edge- worth during the past twenty-four years. He tried to keep his identity a secret. But one of our scouts tracked him down, induced him to sign the letter and permit its publication, on condition that his name would not be mentioned. Larus & Bro. Co. Richmond, Va. Gentlemen: I have smoked a pipe for about forty-four years. In 1900 I read a report issued by some Federal Bureau in which it gave a rating of pureness of nearly all the then best known smoking’ tobaccos. If my memory has not played me a trick Edge- worth stood at the head of the list. I was sufficiently interested to try a can of Edgeworth. Since that time I have smoked nothing but Edgeworth, and when I tell you that I buy a one pound can every week, or fifty-two pounds a year, some- times more, you will surmise that I am some pipe fiend. A pound of tobacco per week for twenty- four years makes twelve hundred and forty- eight pounds of Edgeworth, five-eighths of a ton. The reasons for my loyalty to Edge- worth are these: It is always the same. Seattle, Wash. Another reason is that Edgeworth is sold everywhere. This letter is not for publication, but just in- tended as a notification that you have a few inveterate smokers scattered over the country who smoke Edgeworth because they believe it to be the best tobacco on the market. I have purposely cut off the business heading of this pa- per and will just sign myself Yours very truly, “A qualified judge of smoking tobac- co." Let us send you free samples of Edgeworth so that you may put it to the pipe test. If ~ you like the sam- ples, you'll like Edgeworth wher- ever and _ when- ever you buy it, foritnever changes in qual- ity. Write your nameand ad- dress to Larus & Brother Com- pany, 10 J South 21st Street, Richmond, Va. Edgeworth is sold in various sizes to suit the needs and means of all purchasers. Both Edgeworth Plug Slice and Edgeworth Ready-Rubbed are packed in small, pocket- size packages, in handsome humidors hold- ing a pound, and also in several handy in- between sizes. We'll be grateful for the name and ad- dress of your tobacco dealer, too, if you care to add them. To Retail Tobacco Merchants: If your jobber cannot supply you with Edgeworth, Larus & Brother Company will gladly send you prepaid by parcel post a one- or two- dozen carton of any size of Edgeworth Plug Slice or Edgeworth Ready-Rubbed for the same price you would pay the jobber. POPULAR SCIENCE MONTHLY Gasket Catone eit Cheaply from Pipe and Fittings By Frank N. Coakley TEAM-FITTERS and pipe-fitters gen- erally need a cutter for preparing gaskets, as the jack-knife method is slow and unsatisfactory. When a commercial Although cheaply made, this is a good sturdy gasket cutter cutter is not at hand, a substitute can be made from standard, easily obtained parts. The frame is made as shown, from standard 114-in. pipe and pipe fittings. It is fastened to the workbench with pipe flanges. The feed screw is a piece of the same size pipe threaded the full length. A common valve wheel is fastened to the top of the feed screw. Attached to the lower end of the screw is a collar, which acts as a pull-back for the cutter spindle. A 114-in. pipe cross serves as the nut for the feed screw. The driving spindle is made of cold- rolled steel large enough to fit snugly within the feed screw. A cup-shaped spINnOLe % CUTTER FEED SCREW 4) | : The cutter spindle passes through the feed screw, whichis a threaded length of 1)4-in. pipe washer is pinned to the spindle so as to fit over the collar on the screw. Two pins, one each side of the screw, are forced through holes in thiscollar, as indicated. The mid- dle cross is babbitted to suit the spindle. The cutter head is made from round stock with holes for the cutters and setscrews. The end of the spindle is squared to receive a crank. boiler and drain ing the surface only practical w proofing material or dry surface. E pits, etc. trouble. work yourself. JERSEY MAKE and keep your cellar walls, floor and thoroughly dry by fill- ing the cracks and coat- Smooth-On No. 7, can be effectively ap- plied from inside and bonds perfectly on wet pits with the ater- that xcel- The pit shown at the bottom of this advertisement was below the sewer line and leaked so badly that it usually contained from 6 to 12 inches of water, Since coating the walls and floor with Smooth-On No. 7 the pit remains absolutely dry and gives no more Waterproofing the concrete cellar floor and walls with Smooth-On No, 7 improves sanitary conditions, removes damp and musty odors, valuable tools from rusting, ‘and makes the cellar a clean wholesome place for storing jams, jellies, food, etc. Requi-es about 25 Ib. Sm « th-On per 100 sq. ft. of surface and you can do the Sold in 5 and 10-lb. cans and 25, 50 and 100-lb. kegs SMOOTH-ON MFG. CO. Dept. 60 574 Communipaw Avenue CIiTy, N..J. FREE 800K lent also for patching concrete floors, waterproofing garage, stable and wash. room floors, brick walls, septic tanks, water troughs, fountains, fish ponds, swimming pools, manure cisterns protects ody are headed by en a egal $5. We Fo pice yous ste by ow, Fon gan "Sain Be val . confi ent ractici text material, fncladin f fourteen-vo ferms. Ge our val Ke free’ Bond for teen NOW LaSalle Extension University, De Pero 1083- + Chicage The Worid’s Largest Business ities now “yo 000 to law in fag ern volume La STUDY AT he fy 4 Coy tt y —_ —_ tone a it suce busin cite, gopegening ent, Greater rary. Low cost, eas Law Guide * and Bet ever before. institution’ — Takea W. A. C. Course Engineering. S&S 7 Dept. P-10 in Applied = Monadnock Bik., © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. Pg Aviation men earn $2000 - ‘ad ¥$10, 000 a year. Big Fret outfit of airplane parts. Write for Free catalom WESTERN AIRPLANE CORPORATION Chicago, 1 R If yo below, wrappe! terestin: new me every the edit edit THE E 4050 M Pleas of your in plain Name.. Address City... Wester Fs) 8 3 | 9=s0-8-F :

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ountains, - manure m of this ewer line ¢ usually of water, loor with remains no more te cellar On No, 7 removes protects nd makes place for h-On per ‘an do the cans kegs } CO. ue year. Big Free or Free catalog "ORATION Chicago, 1 1925 EDICAL authorities agree that 65%, or nearly two-thirds, of all men past middle age, are afficted with a disorder of the prostate gland. is the known cause for many of the ailments com- ine ascri to declining years—including aches in men? sect and legs, frequent nightly_risings, sciatic pe nervousness and lack of vitality. But now, science ows that thousands suffer needlessly. For a well known American Scientist has discovered a remarkable new drugless hygiene that usually restores the rostate gland to its normal functioning. Already it has see used by more than 15,000 men—Doctors, Statesmen, Teachers, Bankers, Lawyers, men in every walk of life— with amazing results. FREE BOOK If you will maid the coupon below, you will get, in plain wrapper, a free copy of an in- teresting book describing this new method. It contains facts : mm. every man should know. But send immediately, for the edition of this book is limited: address: Revues og Pin 7 Tre ho et Ming taf Noy . i THE ELECTRO THERMAL COMPANY 4050 Main Street, Steubenville, Ohio. Please send me Free, and without obligation, a copy of your booklet, ‘‘Why Many Men Are Old at 40.’’ Mail in plain wrapper. oo, ee BR eee ere ere Ss ae ee a a a sk is en ass UNI cgi we, st te ss Western Office—Dept. 40-Q, 711 Van Nuys Bldg., Los Angeles, Cal. WY SaexZ SEND FOR CATALOG ia — Over 2,000 bargains in Diamond-set ~ Jewelry, Watches, etc. Sent pre- = for your FREE Examination. atalog explains everything. Money back if not satisfied. SIN /18-K Solid White Gold, 173. $27.5 14-K Solid White Gold; 16 J, $22:58 High-Grade Railroad Watches jarante mee TON gi OP8 Y Jenn, Adee tb Fon 9 "S$ LATEST RAYMOND, 21 Jewels, 8 Adjust-” ments, oes = hours op wingine Ga Adios. § 55 ment of $5.50, then bola Week LOFT IS BROS. & CO. National Jewelers 108 N. State St., Ch‘cago, Ill. Stores in Leading Cities RADIO FANS—“Liste2 in on W. H. T. eve Monday night from 7 to 7:30. Friday night from 9:30 to 10, Central Standard Loftis Bros. & Co.’s hour of music. OF G'S Time POPULAR SCIENCE MONTHLY Stier Shop Methods] How to Fit Up a Lathe to Cut Small Cams ga MANY small shops where there is not sufficient work to warrant the ex- pense of a special cam-cutting machine, it sometimes is necessary to produce a cam by some makeshift method. The lathe is well adapted for cutting a variety of cams and can be fitted up for that pur- pose with little expense. As an illustration of how this class of work may be done on the lathe, the cylin- der cam illustrated is a good example. In this case a flanged plate is made, with the outer face conforming to the cam itself. It is a master cam and produces the same motion. This plate or master ee as CIRCUMFERENCE OF CAM DEVELOPED TOOL OF RIGHT SHAPE TO CUT GROO CAM FORMER G4 FACEPLATE Diagrams showing typical cam and method of using a forming plate or master cam cam is bolted to the faceplate of the lathe and a follower, attached to the lathe carriage, bears against it. A spring or ‘weight also is attached to the carriage by any convenient method to insure a uni- form contact and exert sufficient pressure against the plate to overbalance the pressure of the cut. The cam blank is mounted on an arbor that is driven with a dog. A tool of the right shape is made for the groove. This is fed in slowly by hand to the proper depth. The tool should have sufficient side clearance so that it. will not drag or tear the m>tal. A great variety of cams can be pro- duced by this method and in many cases the time required for making them will compare favorably with special cam- cutting machines.—J. A. Horton, Se- bring, Fla. Small Fillet Tool for Lathe REP VICEABLE fillet tools can be made quickly and cheaply as illustrated. A piece of machine steel 5¢ by 1 in. is used for the shank; the cutting point is made of drill rod. The end of the shank is grooved to receive the drill rod. Cut a short piece Up ofthe rodand bevel MACHINE one end to give it STEEL the proper rake and clearance angle. After hardening and tempering it, fasten it to the shank with solder. Build a bank of solder well up in back of the poimt and along the edge on each side.—H. L. W. DRILL ROD “ngage SOLDER How the tool is made 143 eep fit to This 64 page book tells about the various mod- els, with pictures of professionals using them, Send coupon or postal for your free copy. When the baseballsea- son is over, Benny Ben- gough, star of the New York Yanks, keeps fiit and makes big money playing the Buescher Sax- ophone with Harold Ox- leys Orchestra. Summer and winter he’s the center of at- traction, always in perfect condi- tion. Play Jazz In 10 Days The lure of jazzis yours with a Buescher True-Tone Saxophone. Young folks are enemored by these tantalizing tunes. They love that syncopation. If you want to be popular -if you want to be admired - favored, get this wonderful instrument. At home, at parties, everywhere, the Sax- ophone player is the center of attraction. See How Easy It Is Everyone has a perfectly normal desire to produce music, yet most people have aot the time nor patience to become a musie cian. Buta 277 BUESCHA “Olruevione SAXOPHONE is different. It looks complicated, but is really very easy to play. With the aid of three free lessons, the scale can be mas- tered in an hour; in afew days you can be playing jazz tunes. Practice is a pleas- ure because you learn to play so quickly. Buescher Grand Trumpet Especia‘ly easy to blow, with an improved bore and new proportions. Withthe mute in, it blows so softly and sweetly that prac- tice never annoys. Six Days Free Trial, Easy Payments Send for a Buescher Saxophone or a Cor- net, Trumpet or Trombone for six days free trial in your own home. Send no money. If you like the instrument pay a little each month. Clip the coupon now for your free copy of the beautiful Saxo- phone Book or catalog of any instrument. Noobligation whatever. Doit today. Now. » BUESCHER BAND INSTRUMENT CO. Everything in Band and Orchestra Instruments | 990 Buescher Block Elkhart, Indiana Clip the Coupon NOW!) 7 | ° BUESCHER BAND INSTRUMENT CO. | Mart | 990 Buescher Block, Elkhart, Indiana [7 Without obligation to me,send book ‘“The | Story of the Saxophone”, Check here (J If you prefer other literature describing other band or orchestra instruments, check below. Cornet(J Trumpet{j Trombone[] TubaQ] j Mention any other......-ceesseceecene eeevccere Write plainly, Name, Address, Town and A State in Margin Below © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

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144 EARLE E. LIEDERMAN The Muscle Builder Author of *‘ Secrets of Strengt th,’’ **Here’s Boge.’ 9” ** Science of Wrestling,’ ‘‘Muscle Building,’’ —And the Best Man Won! Crack! His fist landed squarely behind the bully’s ear and down he fell in a heap. Quick as a flash he turned to face the other hold-up man who, with fist closed, was right on top of him. Another thud and another limp form lay on the ground. Quivering with tense excitement, he stood over the two prostrate figures waiting for them to get up. But they did not move. Both were knocked cold. Smilingly his sweetheart came toward him and, patting him on the arm, she said: “I am proud of you, but I knew you could do it.’ A small crowd gathered. Admiring and envious eyes watched the young man and his sweetheart as they slowly moved away. Even the policeman who had arrived on the scene was loud in his praise. HOW DID HE DO IT? “I can thank Earle Liederman for that,” was his first remark as they walked away. ‘*Six months ago I would never have dared to face one man, and certainly not two at the same time. That system of his sure did put me in fine physical shape. Now I am ready for anything and I never know what it is to be afraid. The bigger they are the harder they fall.’ WHAT WOULD YOU DO? Suppose someone tried to bully you, would you run away? Do you possess the muscular development and the courage that goes with it to resist an insult? What would your wife or sweetheart think if they found you played the part of a coward in a circum- stanceliketheabove? There is no excuse forit. Any man may now fortify himself and BE PREPARED to cope with any such emergency. I can take that body of yours and in 30 days I will add one full inch of muscle to your arms. I will add two inches to your chest at the same time. But that’s just a starter to show what I can do. I give you not only muscular arms, massive legs, deep chest and broad back, but I strengthen every muscle in and around your vital organs. My system is progressive. I work on every muscle in your body. I’ll make a he-man of you. I'll fill you full of vitality and pep. I'll put a spring in your step and a flash in your eye. I'll give you the courage that goes with a perfect functioning, muscular body. You won't know what fear means. I'll make people stare at you and say, “There goes a big two-fisted he-man. Come on boys, let’s get started. Don't waste time. Right now, before you turn this page, Send for My New 64-Page Book “MUSCULAR DEVELOPMENT’’ It is FREE It contains forty-eight full page net aphs of myself and some of the many prize-winning pupils I have trained. Some of these came to me as pitiful weaklings, imploring me to help them. Look them over now and you will marvel at their pres- ent physiques. This book will prove an impetus and a real in- spiration to you. It will thrill you through and through. AllI ask is 10 cents to cover the cost of wrapping and mailing and itis yours to keep. This will not obligate you at all, but for the e of your future health and happiness, do not put it off. Send to-day—right now, befvre you turn this page. EARLE E. LIEDERMAN Dept. 1310 305 Broadway New York City ee! eared poe! ecm POPULAR SCIENCE MONTHLY EARLE E. LIEDERMAN Dept. 1310, 305 Broadway, New York City Dear Sir:—I enclose herewith 10 cents, for which you are to send me, without any obligation on my art whatever, a copy of your latest book, ‘‘Muscular I Bovdopanat.’ ** (Please write or print plainly.) PERIRD .o cwcwencocncccwenccee Pe hte eee ] Street --.--------------------------------- ae | Nc cewmedtaseadan ance) TRA eccececns------- | een en a ee eee © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. Be setter Shop wvicthodls | Doing Things the Easiest Way in a Machine-Shop By E. C. Fellows eens in small holes through long hubs sometimes can be cut with a boring-bar in the lathe more efficiently than by taking them to a keyseater or shaper. A square-nosed tool is put in the boring-bar for this purpose, as shown in Fig. 1. The carriage is moved back and forth by hand, while the depth of cut is adjusted by the cross-feed screw. A few long nuts, or bolt couplings, are a useful addition to the shop’s supply of planer bolts. With a stock of rods of varied lengths threaded on both ends, a PLANER TABLE OUPLING FOR J PLANER GOLT SPURS LATHE CENTER Cutting a keyseat in a small, long hub, and five other time-saving shop expedients planer bolt of almost any length can be made up (Fig. 2). A nut placed in the T- slot serves for a head. The couplings also can be used to extend the regular T- head bolts. For sawing in close places the narrow hacksaw frame, shown in Fig. 3, cannot be beaten. It is a useful tool for such work as cleaning up the corners of key- seats that have been chipped, and for sawing obstinate bolts in places too small to admit the regular frame. Another October, 1925 Squab Book FREE Squabs selling at highest prices ever ki Greatest market for 20 years, Moke a ni breeding them. Raised in one month, W, ship everywhere our famous breeding and supplies. Established 24 ao Write now for big illustrated free eae » Howto Make Money Breeding Saute PLYMOUTH ROCK ‘616 H St., Melrose ut AGENTS 500% PROFIT GENUINE GOLD LEAF LETTERS Guaranteed to never tarnish, Anyone put them on stores and office w: Enormous demand, large profits, Paula says: smallest day $28.70. - Reel made $920 in two months, Write today for sample and liberal offer to general agen METALLIC LETTER CO., 433A N. Clark Street, Chica, experience ae ed. We show you HGwe Our easy f payment plan makes it easy to/é start Weequip youcomplete Our eS Our Catal (T'] machinesusedand endorsed bygov- a Free Shows ermmentinstitutions. Write today for free ca‘ STA Lad ATLAS MOVING PICTURE CO. eae) te) 636 S. DearbornSt, Dept. 71 .Chicago \AGENTS / Stamping names on Pocket Key Protectors; sample Check with your name and address, 25c. Stamping Outfits, Emblem Checks, Fobs, Name Plates, HART MFG. CO, 305 Degraw St, Brooklyn, N. ¥, I will put you in business as my Direct FACTORY AGENT AND JOBBER, to take orders for my full line of candies, chocolate bars, mints and chewing gum. Unlimited opportunities for hustlers. No _ experience needed. I furnish everything. Every store and everybody buys. Work spare time or : . fulltime. Write today for catalog, selling pian nak FREE SAMPLES. Exclusive territory. ACT QUICK, MILTON GORDON, 895 Jackson St., Cincinnati, G é b ood, ae pee Oliver— prices smashed to almost half, . 2 and it’s yours All late models, Core letely rebuilt andre- @ Sashes! brand UARANTEED for ten “4 Send 1 no money—bi FREE catalog dé i aoe actual machines in full colors. Get ar anna easy ment plan and 10-day free trial offer. Limited time, so write Sneovuntional Typewriter Ex., 186W. Lake St. Dept. 1088, Chicago Class Rings and Pins Largest Catalog Issued —FREE Prices Samples loaned class officers. $.20 to $8.00 each. No order for class, society or club em- blems too large or too small. Special designs made on re- 8 quest. 30 Days Free Trial seet) tr from 44 Styles, colors J famous Ranger bicycles. ff Delivered Pt, val, Factory Prices, on aporoyal 50". iiieapiee. 85 a if desired . Parents often advance first deposit. Boys can earn small! paymen ‘Tires wheels, lamps, me half usual Reices: Send Han, ekg Write for our marvelous prices and terms. Mead sirtStnass 5 SEND FOR THE INTERNATIONAL CATALOS Gur net price Full line d auto bodiet and access ries for Fords hacksaw kink is shown in Fig. 4. A solid (Continued on page 145) FOR olds Prices from m $27.85 85 u up. “Factory to di t—' Profit International Body Works, "14 W ” Ohio St., Dept. 8, Chicago, lh Octob BETs3s ME ee wD | it _ #2 @-——~_~-

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ctober : 1925 Anyone Cay ice win ts, Paul fam L. Reel m oday for free eral agents, rk Street, Chicap, peeing 23 On Pocket 3; Sample our name and Stam Ding blem Checks, lates, ' IFG. CO, Brooklyn, Ni. , ti 3 s my DIRECT IBER, to take lies, chocolate m. Unlimited 10 experience . Every store spare time or g, Selling plan . ACT QUICK, incinnatl, & ne, 80 write ep t. 1038, Chicago d Pins 1ed —FREE fficers. Prices order b em- small. yn re- Rochester, N.Y. \L. CATALOG ir net price list Full line d E> auto bodiet and access ries for Fords at W Prices, Savt ~~ _ big money # odies by Jirect from Factory: actory to Profit dept. 8, Chicago, lb je ~ october, 1925 thousa! f satisfied users. thousands th Solid Rubber Case, an insuranc® against acid and leak- age. Yousave 60 per cent and geta 2-Year Guarantee in Writing {WORLD Bet. | Approved “ell their friends.’’ That’s our best proof fand Listed e. Send your order in today. Ss dard Rubber Case Radio Batt as Standar 1.25 | by Leading eries $11.2 Authorties foctoding Radio S | News bora- tories, Popular tare nsti- e 16. Just state bat- Send No Money 723¢ ci3'¢ 035 ards, = 1 ship day order is received, by Ex- 10 ose vo wt 0. D. subject to Four exainination Ftadio on arrival. FREE ‘‘B’”’ sattery included. tories, Radio : flor: ® per cent discount for cash sin anat Heee er. Bu w an = ° fo full battery at 60 per cent matin tonous. and Lefax, WORLD BATTERY COMPANY 1229 So. Wabash Ave., Dept. 7 CHICAGO, ILL. Set your Radio Dials at 210 meters tor the new 1000 watt World Storagc Battery Station, WSBC, Chicago. RAGE BATTERIES Watch for announcements. KOKA= WEA Ww tories, Broad JZ KGO > KFAF> WIY>KOP OWN AW al” ort “and it's yours} if. you clip this naw The ace of writing machines—at a bargain price! A free trial, and easiest monthly payments if — buy! This Underwood No.5—rebuilt from top to bottom— fve-year-guaranteed—removes the last reason for not owning your own machine. Get our proposition with new and valuable Typewriting Manual, free. ! Typewriting Manual, large catalog, and FREE full partica ars of free course in touch ® writing, if you mail this to SHIPMAN- | Warp Mr. Co., 2147 Shipman Bldg., Chicgo, Name | Address ............ Maem we etme we eee cdi. ale Interference oipite Eliminator 50,000 Sold First 8 Weeks—Every Radio'Owner'Needs One Select Station at Will Cut out interference and un- desired stations. Tune in loud and clear. Results amazing with any make tube or crystal set using any kind of aerial except loop antenna. . DECREASES STATIC as | POSTPAID! Better reception or your money refund- ed. Bank guarantee. Assembled complete; attach to N\ aerialintwominutes. Notools. Doesn’t disturb present log. No additional tubes or batteries. soy *S time’’ . Send $1 Bill Now 273 2107, Sonnet He want So Sway with interference. Complete Radio lit e FREE. STEINITE LABORATORIES, Dept. 400, ATCHISON, KANSAS DEALERS—JOBBERS. Write for discriptive literature and prices Steinite Nationally known popular price Radio Sets. POPULAR SCIENCE MONTHLY BeneniSNOpaneTnods Laying Out a Templet for a Circular Forming Tool HILE at first glance the circular forming tool illustrated below seems to be of the simplest type, it caused considerable difficulty at one time in a ball-bearing plant where the writer was employed. When the tool was ground at angles of 6 and 8 degrees for clearance, the finished work was not the perfect 3¢-in. radius that was required, but was somewhat elliptical. The engineer in charge tried to draw a lay- out for a templet to be used in grinding the tool so that the work would be true, °/n" DIA. HOLE BORED JN LATHE = CUTTING EDGE SAW ON MILLING MACHINE SPINDLE = il : mie -— =- / ! \ TOOLMAKER'S VISE ANGULAR SCRIBING ‘CONTOUR / SAW CUT OF ANGULAR CROSS CUT A brass bar, bored and cut at the proper angle, is used in preparing the templet but finally he gave it up and told me to grind the tool as best I could, after point- ing out the need for absolute accuracy. I put a piece of round brass in a chuck, bored it out to a diameter of 34 in., put it in a toolmaker’s vise set at 6 degrees one way and 8 degrees another, and cut off a piece. The cut end was laid on a piece of sheet metal and a line scribed around its inner contour. A templet then was made by filing up to this outline and the tool ground to suit. The work came out a true 3%-in. radius. I have since used this same method with good results for solving similar problems in the toolroom. —Huco LJUNGQUIST. Doing Things the Easiest Way (Continued from page 144) frame may be made adjustable by adding a rod with holes for a pin at points to suit shorter lengths of blades. The center shown in Fig. 5 is useful when patterns are to be turned in an engine lathe. It is simply a disk of steel or brass with a 60-deg. center on one side and four teeth to be driven into the wood onthe other. This holds solidly and does not tend to split the pattern. An easy way to make a set of trammel points is illustrated in Fig.6. The bodies can be made of 34-in. key steel, the bar of 3%-in. drill rod, or cold-rolled steel, and the points themselves of %,-in. stock. The points are either ground eccentric or bent, to permit of fine adjust- ments by turning the point in the body. The coupling is added so that the rod may be in sections short enough to go in the toolbox. 145 **Bill Carola’® Landaus Couldn’t Play a' Note — Now Makes *100% “When I sent for your catalog, I didn’t know a note of music. A few months after I bought my Wurlitzer instrument, I had taken my place in a professional orchestra, Now I am making $100 a week, three times what I madeasaclerk. I — oe raed a easy it is— anyone who can whistle a tune can learn to a musi- cal instrument.”—Bill Carola. _ Free Trial—Easy Payments You may now have any Wurlitzer instrument fora week’sfree trial in yourown home. Examine the instrument, note the fine workmanship, the full, rich tone value and a how easy it is to play. No obligation to buy—no expense for the trial. We make thisliberal offer because we want you to try for yourself a genuine Wur- litzer instrument, the result of 200 years’ experi- ence in musical instrument building. Easy payments are arranged to suit your con- venience, Thisis your opportunity to try a fam- ous Wurlitzer instrument in your own home. for PCC BOO § Illustrates and describes every known musical instrument—more than 3000 ar- ticles, many of them shown in full colors. All genuine Wurlitzer instru- offers on complete outfits. r We also give you our Free & Trial, Easy Payment Plan, & No obligation. ¢ TheRudolph WurlitzerCo. , Dept. 1787 117 E. 4th St. Cincinnati 329S. Wabash Ave. Chicago | 120W.42ndSt.NewYork 250StocktonSt.SanFrancisco \\ | Send me your Free Book on musical instruments. Also j{ your Free Trial, Easy Payment Pian. No obligation. Name Address City State Instrument ) Wurtilzer Copyright 1925, TheRudolph Wurlitzer Coe & This seal on a radio or tool advertisement signifies the aPrroval of the INSTITUTE OF STANDARDS. See page 6.

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POPULAR SCIENCE MONTHLY Ya ECTRICITY — Will Close the Big Gap Between Your PRESENT and Your FUTURE! Does your present job offer you a FUTURE? If 80, how long must you wait for that future? Five?— ten?—fifteen?—perhaps twenty years? TOO LONG “i to wait for an uncertainty! Too many things \ can happen in that time to rob you of the fruits \ of your hard, earnest labors. GET WHAT YOU \ EARN—now! Drudging through the years in hopes that mere chance will provide a big future for you is like wandering in a fog with -| little prospect of reaching your destination. Get into IMPORTANT work, where your services will be needed, not merely tolerated. The Electrical Field offers Thrills Galore, a Experiences, and SALARIES that y he-man —— brag about! COME OUT OF THE "FOG AN BE HAP- PY—in the Blewreat Field! REMEMBER, THERE IS NO SUBSTITUTE FOR PERSONAL TRAINING, IN GREAT SHOPS, ON COMPLETE ELECTRICAL } APPARATUS, You don’t need advanced edu- rg a edge of higher mathematics or experience in order to learn at COYNE. Earn WhileYou Learn My Employment Dept. helps you get: et a job to earn partor all SoAMAKTATHANANAANNANMN HUNDREDS = RAILROAD FARE TO CHICAGO = OF COYNE- == from any point in the U. S., also extra courses in Radio TRAINED Se ests WITHOUT EXTRA COST If vou oct monn. = MEN EARN = Remember, Chicago ls a wonderful city to eee at any 5 = Ercat clgctrical center of the world. Tule offer wittoson = $60 TO $200 , SMM =| A WEEK Uw. o. tews, presisent COMPLETE ELECTRICAL TRAINING and Special Offer of R.R. IN 12 HAPPY WEEKS AT COYNE Fare and 2 Extra Courses chews pertested —_! pions tieirestion’ ~ agers A a course that is absolutel. oroug at is easy to master, that covers ever. Complete Etectrical Fim og [— ee single phase aes | factor of the subj ect, that fits men for the BI hing, ante or Later electrical jobs—the HIGH-SALARIED thrilling jobs. Send For My Big Free Book COYNE does not teach by correspondence, but by practical, personal ms. umtetelaees k that Sie, etme, oo you a training in the wonderfully- geo COYNE Shops, locatedin Chicago, once. Itig 12x15 in size fseand contains 161 actual the electrical center of the world, At COYNE your training is really ee ee ee ee PERSONAL and PRACTICAL, on the most MODERN and COM- lighting analy power, etc. Nothing like it. vont il PLETE electrical apparatus, under guidance of thoroughly-qualified in- be amazed. ABSOLUTELY .» REMEMBER. structors. You also visit greatindustrialorganizations and power plants. SEND COUPON NOW H. C. LEWIS, President COYNE ELECTRICAL SCHOOL 1300-10 W. Harrison St. Dept. 1367 aoa, Iinois Tune in on COYNE Radio Station WGES COYNE ELECTRICAL SCHOOL H. C. LEWIS, President Established 1899 1300-10 W. Harrison St. Dept. 1367 Chicago There is no Substitute for Personal Training, in Great Shops, on COMPLETE Apparatus 1 actual p ——- Bend it quick, be fore the cupply is exhaus' Be sure to tell me all about ae Carer of Rail- road Fare ends Big Courses. Name Add: © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. Readers of POPULAR SCIENCE MONTHLY will find scores of oppor- tunities in this section (pages 146 to 174) for making more money. $ 10 () in CASH PRIZES Every reader of POPULAR SCIENCE MONTHLY is in. vited to enter this contest. For the best letters of 100 words or less answering the question— “What Advertisement in the ‘Money-Making Op. portunities’ Department in this issue interests you most—and why?” we will paythe following prizes FIRST PRIZE $50.00 SECOND PRIZE 25.00 THIRD PRIZE 10.00 FIFTEEN PRIZES OF $1.00 EACH 15.00 First read every advertisement in the Money-Making Opportunities Section on pages 146 to 174. Pick out the one that interests you most and then write a letter—not exceed- ing 100 words—telling us why you find the advertisement you have selected the most interesting. Entries for the contest will close on October 1st. The prize winners and their letters will be published in this section in the December issue. Address your letter to Contest Editor MONEY-MAKING OPPORTUNITIES POPULAR SCIENCE MONTHLY 250 Fourth Avenue, New York a me et eet eee at te et OD

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t. For rds or ‘ion— nt in Op- ment s you 5 ] prizes ..00 00 1.00 00 ent in inities » Pick 1 most xceed- Ly you | have ye | close inners lished >mber IITIES THLY rk | | | | ” a on Lee a {h—\ Or Simple Lesson in By A. H. WARD You may think that my arithmetic is funny, but it certainly worked for me. You can add ten and ten in the ordinary way and you’ll never get more than $20—and that’s just about what I was earning a week before I left the States for twenty months’ active service in France. When I came back I determined that I would not go back to the old grind! I found a way to put one ten alongside of the other so that the total made over a thousand dollars—and that’s what I averaged every 30 days for the last twelve months. Through the simple method I'll tell you about I made $13,500 last year. HERE’S no reason why any ambitious ie should not follow in my footsteps. I read an advertisement, just as you are now reading my story—It told about W. Hartle of Chicago who had been in the R. R. Mail service for ten years. Hartle made a sudden change—against the advice of his friends—and made over $1000 the first two weeks. Berry of Winterset, lowa—a farm- hand—made $1000 the first month. George Kearns made $523.00 the first two weeks. F. Wynn made $554.37 the first seven days and Miller, a former stenographer, made $100 a week after making this change. Well, man, I sat up and took notice. If they could do these things—ordinary men like myself—I knewthat I hadachance. I investigated and found that what the adver- tisement said was true. Fact is, you can figure it out for yourself in simple logic. Consider these two points. Easy for Two Reasons First: There is no money and no future in the routine job. Everyone knows that. If you want to make the real money, you must get into the producing end of the business— be a salesman. Wait, now, don’t let the word SALESMAN scare you. For the sec- ond thing is this: Salesmanship is governed by rules and laws. It is just like learning the alphabet. And men who always have thought that salesmen are “‘born’’ and not made, very quickly learn that there are cer- tain definite ways to approach different types of prospects to get their undivided at- tention—certain ways to stimulate keen in- terest—certain ways to overcome objections —batter down competition and make the r ee _ cents. And on the other hand you may find a way‘ prospect act. And any man can learn these to double or triple your salary in a short period. simple principles. I know that because J’ve — = the attached coupon today with your name : and address. proved it to myself. Yours for CUTE wand : ; ’ > elie > A > idle; A. H. ard. A Of course I didn t know it then. The idea Written for Mr. J: E. Greenslade, President just appealed to my common sense or reason National Salesmen’s Training Association or whatever you call it. I sent for the book that Mr. Greenslade, the president of The National Salesmen’s Training Association, will send out ab- solutely free to any man who writes, This Free Book Started Me After reading this re- markable book I enroll- ed. Don’t think I’m boasting, I’m just stat- ing facts. Within one year I had averaged over $1000 a month in- come—$13,500 the first year—and in addition fore Money rithmetic Send Today for Free Book If you really want the good things of life—the things that only money can buy—I urge you to send the request blank on this page to Mr. Greenslade. He will send you Free and without any obligation ‘‘Modern Salesmanship,’’ the book that started me on the road to success. Then decide for yourself. Even if you don’t go ahead you will be out only two 56-D N.S. T. A. Bldg., Chicago, Illinois. dt t f 5 f OLOEST AND LARGEST SALESMANSHIP was elected as an officer of Postl’s of Chicago. Now don’t misunder- stand me. I don’t say that you can do as well. You may not make a thousand dol- lars the first month. You may not have as much determination to succeed as I had, you may not have the driving force behind your efforts that spurred me on. But I do say that since looking into the matter can’t cost you a cent, you should at least in- vestigate. You can’t help but benefit and if you’re any man at all you should double or triple your income without half trying. I’m not particularly keen for the publicity this story is giving me. My friends may laugh at me for allowing my picture to be printed here with my name, but I dosoany- way because I realize that my story may be instrumental in showing other mena quick, easy way to realize their ambitions and make the dreams of their hearts come true. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. National Salesmen’s Training Association Dept. R-15, N. S. T. A. Bldg., Chicago, Il. | MR. J. E. GREENSLADE, PRESIDENT, : } National Salesmen’s Training Association, sc | Dept. R-15, N. S. T. A. Building, Chicago, Illinois | Send me free the book that gave Mr. Ward his start. This | does not obligate me. | Name... nee ee see ee ae a dh av Geis coat es ehseicah oak we | II os cin omnes se cee co eres kn ae hes ce in Ge Se rane ee |

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Cc " nta Monica, Cal., 000

trip. (Wide World Photo.)

Daring Young Needed in Aviation HERE is no field of workin the One student, S. F. world today’ which offers such Chicago, says: amazing opportunities to young “Your lessons are like a romance, and what is men of daring and who love adventure more, after one reading, the student gets a thorough ’ as does Aviation. Although still in its McNaughton, understanding. One never tires of reading them.” James Powers, Pa., another student, says: “I am indeed surprised that such a_ valuable

infancy, there is a crying demand in Aviation for young men with courage, nerve and self-reliance. For those who can qualify there will be thousands of highly paid jobs which will lead quickly course can be had from such practical men for so little cost.’’ Personal Instruction by Experienced Men

and surely to advancement and success.

Men who have had actual experience in Aviation give you personal attention and guide you carefully through your training. They select the lessons, lectures, blue- prints and bulletins. They tell you the things that are essential to your success. Every lesson is easy to read and quickly understood. Big Book on Aviation FREE Send coupon below for New Free PREPARE For One of These POSITIONS Aeronautical Instructor $60 to $150 per week Aeronautical Engineer $100 to $300 per week Aeronautical Contractor Enormous profits Aeroplane Repairman $60 to $75 per week Aeroplane Mechanician $40 to $65 per week Aeroplane Inspector $50 to $70 per week Aeroplane Salesman $5000 per year and up Aeroplane Assembler $40 to $65 per week Aeroplane Builder $75 to $200 per week Big Opportuni- ties Await ; the Trained Man Look over the fields of work which are open to the young man _ today. You will find that Avia- tion is the ONE FIELD that is not overcrowded— the ONE FIELD in which there is plenty of room at the top. Think of it! Only 21 years ago Orville and Wilbur Wright made the world’s first airplane flight. Now airplanes fly around the world. Yes, Aviation offers the same wonderful oppor- tunities today that the automobile and

motion picture industries did 15 and cag) Fe 20 years ago. Men who got in on portuni- the ground floor of those indus- , ates tn tries made fortunes _ before fp the Air- others woke up. AVIATION IS * plane Indus- NEW! It clamors for nervy try.” It is _ interesting and instructive and will show you many things young men—and the trained man has the world before him in Aviation. about Aviation which Easy to Become an you never knew before. Aviation Expert—$50 to Only a__ limited number $100 a Week offered—get yours before the edition is exhausted. AMERICAN SCHOOL OF AVIATION Dept. 1367, 3601 Michigan Ave., Chicago, Ill. nan nn AMERICAN SCHOOL OF AVIATION, | | 3601 Michigan Ave., Dept. 1367, | Chicago, iil. Without any obligation, send me your Free i Book, “Opportunities in the Airplane Indus- You can qualify now quickly for one of these exciting, highly paid jobs through a new, sure, easy method of training. The study of Aviation is almost as in- teresting as the work itself. Every lesson is fascinating and packed full of $ ’ nati i try,” also information about your Course in ! interest. That’s why Aviation is so easy ‘slr pees ra \ to learn—you don’t have to force your- i self to study—once you start, you can’t ] SN Se Looe Seah Sry ieee a is os oS so POAT j get enough of it. Only one hour of spare =| Street...0... 0... ccc cece cece ee eee cee eee 1 time a day will give you the basic train- |<. i ing in an amazingly short time.

I It Is Easy to Succeed (Continued from page 4) write to the advertisers who are ready to help you reach the top of the profession or trade you have chosen. The man who has a driving ambition to get ahead can secure a specialized training without its interfering with his pregent employment and at a cost he can afford, Correspondence schools, extension courses, and educational books show the way to the man handicapped by a lack of education. POPULAR SCIENCE MONTHLY is the great meeting-place for men-who-want-to-gue. ceed and the schools and publishers who can help these men achieve their ambitions, Every month you will find in Popuzar SCIENCE MONTHLY hundreds of adver. tisers holding open to you the door to success. Starting with this issue these money-making opportunities will-be grouped together for your convenience jn finding the path you want to follow. Read every advertiser’s offering, see what the opportunity is in each field, decide which calling you have the greatest natural in. terest in, and then go to it with all the determination you possess. Only education, plus determination to succeed, can make you a success in life. As a further incentive to succeed we are offering $100 in Cash Prizes for the best letters telling us the advertisements our readers like best—and why. See the details of this offer on page 142.

New Process of Welding YHROMIUM and other metals that cannot be welded by ordinary meth- ods are: conquered by a new discovery made by Dr. Robert W. Wood, of the Johns Hopkins University, working for the General Electric Company. The stubborn metals are welded by breaking up hydrogen into dissociated atoms, which is done with electricity.

Special Rooms for Tall Men VV Ss tall men stop at hotels they often find accommodations cramp ing. Ever obliging, one big New York City hotel is altering rooms on its top floor, especially to suit six- and seven- footers. Door frames will be built so that the lengthy guest need not bump his head. Extra long bathtubs and beds and other furniture built to special measurements, will add to the visitors’ comfort. Chew Well to See Well (CHEW well if you would see well, urges Sir Arthur Keith, a great British anatomist. Decreased exercise of the jaws, and not eye strain, is causing short sight, he claims. Diminished use of the jaws in masticating the soft foods of modern diet, he asserts, is changing the shape of the face, lengthening the eye sockets, thus elongating the eyeballs and weakening vision.

‘““Up to the Minute”’ I find POPULAR SCIENCE MONTHLY 28 interesting as my radio set, and they both keep me informed right up to the minute.—E. H., Bogota, N. J.

—

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

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ceed e ready to Profession mbition to ed trainj lis present n afford, extension s show the by a lack is the great ant-to-sie. ishers who ambitions, 1 POPULAR of adver. | e door to ssue these 28 will-be renience in low. Read what the cide which 1atural in- ith all the ‘ination to s in life, eed we are r the best ments our See the ling etals that ary meth- discovery »d, of the orking for ny. The ’ breaking ms, which 1 Men otels they ns cramp. Jew York n its top nd seven- ) that the his head. and other urements, le Vell vell, urges t British e of the sing short ise of the foods of nging the ' the eye balls and NTHLY a8 and they ip to the October, 1995 Auto Electricity pays W. E. $9,000 Pence, Albany, Ore., over a $9,000 a year. 58 men enrolled for this training on his rec- Y eal ommendation. as a is x 125 “‘Depend on me as a booster,’ says A. Schreck, Phoenix. Arizona. “I make over $500 Week a month. Your advertise- ment started me tosuccess.”” WONDERFUL WORKING OUTEITS* Given worth ene extra charge ! PERI- y AND ex! Lia LABORATOO Tet 1T. ti contrat ° 1 pent ai for interest! NtS ve on ALARM ouTrl yparavete install- **Thanks t I made $700 i S700 tn serine cNa ri te bg 24 Days = Ga."*I t—* your training everywhere.’ These Four, and Thou- sands of other Men earning $70 to $200 a Week, Recommend This Training to You! John Jirinec, 1133 Fourth — Avenue, Astoria, L.I., now earning "342,000 a ear, rec ommends Cooke raining. START NOW Be an. ateend He "says, ‘It alone is Te; LEARN to EARN $3,500 to $10,000 a Year! Don’t you keep on working for only $25 or $35 a week. Get into Elec- tricity. Thousands of Cooke Trained Men who knew nothing about it a short time ago are now earning $70 to $200 a week as Electrical Experts—and they don’t work half as hard as youdo. Why stick to your small pay job? Why stick to a line of work that offers no chance—no promotion—no big pay? Get into the world’s greatest business. Electricity needs you. I'll show you how to doit. Get ready for the big pay job now. Electrical Experts Are In Big Demand Even ordinary electricians—the “screw driver” kind—are making big money, but trained men—Electrical Experts who get the top salaries—are needed more now than ever before. Thousands of Cooke Trained Men easily earn $3,500 to $10,000 a year. That’s the kind of a job you want—where you can plan and boss and supervise the work of others or go into business for yourself. Get started towards one of these big-pay jobs now. Learn to earn $70 to $200 a week — you can do it with Cooke Training — recommended by more than ten thousand successful graduates. Just mail the coupon below. Age or Lack of Experience Bars No One You don’t need experience. You don’t have to be a College man. You don’t have to be even a high school graduate. As Chief Engineer of this big two million dollar institution which does a general Consulting Engineering Business besides operating one of world’s great- est Training Schools, I know just what training you need to make a big success in electricity. Employment Service — No Extra Charge I will train you for a big pay job and then help you get it without extra charge. Hundreds of Em- ployers look to me for the electrical men they hire. Last year I placed over one thousand men at big raises in pay. Hundreds of others were promoted by their employers through the help of my Vocational Service and other hundreds went into business for them- selves with the help of my special Business Training. Ma. il Coupon for big free book which explains this service and fourteen other features, many of which can’t be had anywhere else. Let me give you that training with my simp lified , = home course—the world famous ‘‘Cooke ‘Training’ }—puilt on my own 20 years of engineering experience with the help of nearly 50 other engineers. Learn to earn $70 to $200 a week—- only spare time needed. My Training Pays For Itself You can start earning extra money a few weeks after you start my training. I give you special instruction for doing simple electrical jobs in your spare time—show you how to get these jobs and tell you what to charge. Many of my students make as high as $25 a week extra this way while studying. My course more than pays its own way. Your Satisfaction Guaranteed I am so sure! can make you a big success in Electri- city, just like I have done for the men whose pictures you see here and thousands of others who now boost my training, that I will guarantee your satisfaction with a signed, money-back Pecan bond. If my training doesn’t satisfy you after you ve finished, you get back every penny you payme. Atwo million dollar institution stands back of this guarantee. Get Started Now—Mail Coupon “ Get my big free book—“‘The Vital Facts about Elec- tricity.’”’ Read ahout the success of hundreds of other men— men who recommend this training and whose names and addresses are given in my_ book. Get the real dope about your opportunities in Elec- tricity. See how easy it is to get started onthe road to jobs. that pay $70 to $200 a week. Don’t deny yourself this chance to make big money. Get the facts now — Mail Coupon at once for facts and my guarantee, L. L. COOKE, Chief Engineer CHICAGO ENGINEERING WORKS, Inc. INGOs dic ccurwasaciadcaces © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. ‘ ELECTRICALEXPERT L. L. COOKE, Chief En- gineer, who has trained thou- sands of men for Big-Pay Jobs in Electricity. ENGINEERS’ ASSOCIA- TION ENDORSES COOKE TRAINING The American Association of Engineers, with 15,000 College and Practical Engineer Mem- bers, hasapproved Cooke train- ing and theC. E.W. 100%. Their printed and publiclydistributed report of their investigation is theonlyendorsementofaschool they have ever issued. Full de- tails of this endorsement sent with my free book. eweneeeeceo ee eaeea§ Dept. 37 eo” L.L. COOKE, Chief Engineer, 2150 Lawrence Ave. °° e° CHICAGO a WORKS, e ept. Chicago, Hlinois of 2150 Lawrence Ave., Chicago, Illinois as Send me at once, without obligation, your PL big illustrated book and complete detaiis of o? your Home Study Course in Electricity, including a® your outfit and employment service offer, « a (2 RO CCT POC ECO CCT TET DEE Emre 2

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Aeing SOA ment ae an are antenna a ane Sea emer tne SRR RR EE October, 1935. B.W. Cooke Student Jos. Woronecki Made $300 in a Week! If you want Big Pay, a QUICK raise in Pay ora Business of your own—if you're making a cent less than $50 a weeke—CLIP THAT COUPON RIGHT NOW! I'll send you my big Book ‘‘AUTO FACTS” without a penny’s charge. This Book Has Shown Hun- dreds of Men the Way to Success ! The book that -I am offering to send you ABSOLUTELY FREE is the same book that started hundreds of men on the way to Amasing Salary Increases and big successes as Auto Experts Why Just Look Here! Joseph Wor- onecki, Hartford, Conn., was only making $21 a week when he wrote for my _ book. Recently he wrote that he made $300 INA SINGLE WEEK! Mr. Woronecki is just ONE of HUNDREDS who are making big money as Auto Experts. Send the coupon and I'll give you FACTS—proven facts! I'll show you that YOU can have real success and BIG PAY asa B. W. Cooke “JOB-WAY” Trained Man—if you are between the ages of 15 and 60 and can read and write plain English. Get into the World’s Biggest Business—iIt Needs You! Get all the facts about this wonderful Auto Business—the Biggest Business in _ all the World—it needs you! Zast, West, North, South—everywhere—BIG JOBS pay- ing all the way up to $150 a_ week, are waiting for trained Auto Experts. of Money-Making Opportunities for YOU! Think of it—FIVE Thousand Million Dollars are poured into the pockets of Auto Experts every year in this Gigantic World Beater Industry! Learn how you can get your share of the BIG PAY and get it QUICK! Thousands are watting PROOF! se: wnt! - * Can Do forYou! $700 in Spare Time Money. That's what Cleo Crowl, 215 Washington St., Medford, Oregon, earned in spare time before graduation. See how you canmake yourspare time bring you CASH. 100% Raise in10 Months. HarryAtkins, 38 Day St., Fitchburg, Mass.,made enough in his spare time while taking my train- ing to pay up all of hisdebts—and on top of that Doubled His Salary in a few short months. ag HOME scsswav Keep your present job. Get started on the way to Big Pay as an Auto Expert through Cooke ‘‘Job-W uickly, easily, RIGHT IN YOUR OWN HOME! Being a practical Directing Engineer, Owner and Head of this Institution, I know what practical, money-making training you need to be a BIG PAY MAN—and that training I give you! My free Book shows you how successful I’ve been and how success- ful I am. phe Only JOB ay’ training on Farth? Find out about _ this —also Automotive Magazine, markable ‘QUICK RESULTS” also 3 Outfits. Nowhere else Training.B.W.Cooke‘‘Job-Way”’ can you get the original, genu- trains you to be your own ine copyrighted Cooke ‘‘Job- boss—to hold down the HIGH Way”’ training. I train you SALARIED JOBS. with Tools which I give you, Includes all Electrical work — and illustrated JOBS — not Ignition, Starting, Lighting—all books. Learn what Cooke ‘‘Job- Big Outfits GIVEN Mechanical end, Welding, Brazing, a has 7 ad others. See Vulcanizing—also Business Course, what it can do for you. MAIL Salesmanship, Advertising, _Buy- COUPON TO ME RIGHT No extra cost ing, How to Keep Simple Books NOW! Tools, Test Bench, Ra- You Can Make Big dio Set, all equipment included. oupon brings full details of wonderful offer. Money Too! You've got just as much ability as Walter Mayville, Harold Lester, M. J. Morris- ton, Herbert Trask, Allen Pomeroy and dozens of others, who only a few months after enrolling, were their own bosses, in their own businesses, making REAL money! I'll prove to you that you can reach success quickly and easily too. I[°ll show you how I back you up with the en- Directin COKE, Training . Veen k and proo! Employment Service without extra cost for your entire lifetime. Also Lifetime Consultation Service. Get all the facts. Send for my Big Free Auto Book right awayl Address me Directing t Personally B.W. Cooke Engineer e CHICAGO MOTOR TRAINING CORPORATION 1916 Sunnyside Ave., Dept. 725, Chicago, Ill. If it isn’t ““B. W. Cooke-Way’’— it isn’t ““Job-Way”’ over eoeorr? gspecvoees? ** tire resources of this great Institution—how I give you - What Is Evolution? (Continued from page 26) form was hardly larger than a walnut, hard and bitter. Then there is Luther Burbank with his classic experiment with potato seeds from which there evolved the Bur. bank potato. Today there exist thousands of forms of animals and plants that reproduce their kind that did not exist a century ago, 6. Every-day evidences. Scientists call evolution at once the most obvious and the most vital fact of life as we know it. We see it, they say, in operation al] about us. We see the seed spring into a plant that blossoms and withers. We see the egg change into a chicken, and the tadpole into a frog. Rivers change their courses. The tide rises and falls, Day turns into night. All these changes have been observed by man for centuries, ND science says, too, that we can see evidence of evolution in our gar- dens, among our children, in the mar- velous machines developed for our use from the crudest of implements—even in the ideas that we conceive and unfold, Your life from beginning to end, says science, is change and progress, steady, upward; from helpless ignorance to in- telligence and power. This is what science means by evolution as the compelling force of creation. There are any number of books in which you will find the theory of evolution further described and amplified. For these I suggest that you consult your library. D. A. TURNQUIST, Information Department. An Unnamed New Gas URING the recent eclipse an un- familiar gas was observed about the sun by scientists who were making careful observations. But, according to Prof. Frederick Slocum, head of the Van Vleck Observatory at Wesleyan University, who recently made the announcement, scien- tists are not yet prepared to name the gas or to discuss its properties. Filter Makes X-Ray Harmless FILTER that is said to render X-rays harmless and that is claimed will cure. radio-dermatitis, a disease that has killed and maimed scientists using the rays comes from the Paris Academy of Sciences, The filter is of a plastic material that al- lows only the red and yellow rays to pass. Tiniest Counter Improved i fared accuracy in the tiniest of measur- ing devices—the mechanism by which blood corpuscles are enumerated— recently has been attained by the U. §. Bureau of Standards. In the past, the count of blood corpuscles, an important aid in diagnosis and treatment of diseases, has been somewhat inaccurate. The new method, devised by C. G. Peters and B. L. Page, applies a new principle based on the phenomena light-wave interference under the micro- scope, resulting in greater speed and IS] This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6, accuracy in blood counts. C al you attra ever’ ama: trol succ to st give your any you netic fluer peor an and peric pow' mak be, i the cess: pers cost are | Vy but wom fanc som is y mad resis mag self. vive becom You ¢

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t, hard irbank potato e Bur. forms roduce ry ago, entists bvious > know ion all into a We n, and change 1 falls, hanges ituries, ve can ur gar- > mar- ur use ven in unfold. 1, says steady, to in- olution yn. oks in olution For it your ST, ment, S an un- out the careful 0 Prof. n Vleck ty, who ;, scien- the gas nless - X-rays vill cure. is killed ne rays ciences, that al- to pass. ved measut- sm by srated— 1e U.S. ast, the | |

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Give You a Magnetic Personality Let Me Prove It — FREE! CAN so magnetize your person- I ality that people will be drawn to you at once, irresistibly. Ican make you a magnet of human attraction so that you are popular everywhere, in any society. I can show you how to use the amazing principle of magnetic con- trol to win quick and conspicuous success in your business or profession. I can place in your hands the key to supreme power and happiness— give you a great new confidence in yourself—overcome almost at once any timidity or self-consciousness you may have. I can give you a glorious new mag- netic personality so that you can in- fluence the minds of others, attract people to you instantly, be popular and well-liked wherever you go! Let me prove it. Give me 5 days, and if in that time you do not ex- perience a new surge of personal power, if you do not find yourself making friends wherever you may be, if you do not discover yourself on the road to happiness, wealth, suc- cess—guided by my principles of personal magnetism—the test will cost you nothing whatever. You are the judge. What is Personal Magnetism ? You have it—everyone has it— but only the exceptional man or woman knows how to use it. Personal magnetism is not a fad or fancy; not some sudden discovery or some new psychological theory. It is you, your manner, your self— made magnetic. It is a force as ir- resistible as the force of the actual magnet, drawing a bit of steel to it- self. No leader of men has long sur- No great orator vived without it.

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aT Think what personal magnetism will mean to you in business, in your contact with men and women. You will win! You will get what you want! My Method Releases Your Personal Magnetism No long course of study. No tedious mental exercises. Not the slightest inconvenience or self-denial. Just a simple, clear, age-old principle that taps the vast thought and power resources within you, releases the full sweep of your magnetic po- tentialities—and makes you almost a new person from what you were before. A principle that never fails to work, because it conspires with Nature to make you the dynamic, forceful, fascinating person you were intended to be. Not Hypnotism—But Magnetism! Please do not mistake my method for hypnotism. Its laws and its results are exactly opposite. Hyp- notism deadens—magnetism imparts a joyous exhilaration to body and mind. Hypnotism paralyzes the will—magnetism animates, inspires, sharpens and strengthens the mental faculties. IS] This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. The fundamental principles of Per- sonal Magnetism have been put intoa series of four handy-sized volumes under the title of ‘‘The Cultivation of Personal Magnetism.” These books give you the key to a magnetic personality—or they cost you nothing. That is my free proof offer to you. The study and scope of Personal Magnet- ism is as broad as life itself. ‘‘Fires of Mag- netism,”’ ‘‘Sex Influences,” ‘“The Magnetic Voice,” ‘‘Physical Magnetism,” ‘‘The Mag- netic Eye,” ‘‘The Road to Power” and ‘‘The Winning Personality” are only a few of the subjects covered in this amazing series of books. Remember My 5-Day Free Proof Offer! Send Off the Coupon TODAY You must see them for yourself—examine them—let them influence indelibly your own personality. If you aren’t stirred and in- spired in the 5-day free period, return them and they cost you nothing. Otherwise keep them as your own and remit only $3 in full payment for the four books. You are the sole judge. You do not pay unless you are de- lighted. And then you pay only $3 for the four remarkable books! ; You simply can’t delay! Clip and mail this coupon NOW. Ralston University Press, Dept. 14-S, Meriden, Conn. RALSTON UNIVERSITY PRESS, Dept. 14-S, Meriden, Conn. All right—I'll be the judge. You may send me the four volumes ‘‘Cultivation of Personal Magnet- ism” for 5 days FREE EXAMINATION in my home. Within the 5 days I will either remit the special low price of only $3.00 for the four books complete, or return them without cost or obligation. Name....cceseece COOH SO Ce TEETH EH EHS OH ES ES OOOe Address. .cccccccccccccccccsssessesseeseeseeee CHE. < cocccccccoccccce cctente cease eeeeeeeeee ee

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nanny ing Sn Tne nines chai pe Thousands Can Draw CARTOONS Who Have Never Even Tried Cartoonists earn $60 to $300 a week. Why work at drudgery when through a remarkable new method you can easily learn at home in spare time to cartoons that SELL? ANY are earning pitifully small salaries who could make wonderful salaries in cartoon- ing. Briggs, Fox, Fisher, Goldberg and other leading cartoonists earn more than the President. Yet a few years ago many of our most successful cartoonists never dreamed they could draw a good cartoon! The World’s Easiest, Pleasantest and Best Paying Profession Just watch a cartoonist work. A few little lines—a couple of simple curves—a splash of black here and there —and then you see a splendid cartoon before you. Witha few strokes of his pen, he has taken some little incident of his day’s experience—some humorous or sad scene he has witnessed—and produced a wonderful cartoon. New Easy Way to Learn Cartooning This fascinating ability to draw cartoons can now easily be yours—Through a wonderful new home study method, you receive a complete training in Cartooning, and ~ersonal corrections on all of your work from one of America’s foremost cartoonists! With his help, you can in an amazingly short time, learn to draw the comic strips, humorous, political and ani- mated cartoons which are in such big demand. Learn More About Cartooning Send for FREE BOOK Never have cartoons been so popular. Millions of were spent last year on cartoons of all kinds—and every week newspapers increase the amount of cartoons used. Learn about the amazing opportunities in Cartooning and all about this remarkable home study method. Mail coupon for Free Booklet today. Washington School of Cartooning, Room 2410-C, 1113—1i5th St., N. W., Washington, D. C. Dl le WASHINGTON SCHOOL OF CARTOONING, | Room 2410-C, 1113—15th St, N. W., Washington, D.C. 4 ease send me without obligation your illustrated Pi |. FREE BOOKLET on Cartooning and details of Free | er. raw | >? a ee eee (Write name plainly—State Mr., Mrs. or Miss) | ak gS SE eae Re I I ‘ l | By See eee NR crise iecac | - under 16 years, please state age______________ l SS ASS SS SS A LF A LA se os '“STAMMERING| lfs Guse and Gire You can be quickly cured if you stammer. Send 10 cents, coin or stamps, for 288 page cloth bound book on Stammering and Stuttering. It tells how I cured myself after Stammering and Stuttering for 20 years. BENJAMIN N. BOGUE 7522 Bogue Building, 1147 N. 1. St. Indianapolis BURN YOUR NAME ON TOOLS With THE ARKOGRAF Frotect Your Tools From Theft. write with elec- tricity any name or design on the hard- any . like writing on or pencil. Complete Outfit SO oe giptarent ¢ free. Write to- October, 195 PEN CO. Ii 720A East stork St., Portland, Oregon Can Man Reproduce theSun? (Continued from page 29) reproduce the effect of the sun itself. Dominating the entire plant is the direct-current generator—perhaps' the 10,000,000-volt apparatus now being planned, possibly a greater. High above this stand two giant electrodes, placed 50 or more feet apart. Between them is a complicated network of wires and pipes connecting with tanks and vacuum chambers in which is stored until needed the power generated by the plant. The operator is seated at a switch- board in an inclosure of heavily tinted glass. He glances at a typewritten order, closes the door of his glass house and twists two or three dials. ‘‘We are going to disintegrate helium atoms this time,” he remarks. “A pound of helium releases a radiation of heat equivalent to that given by burning 10,000 tons of coal— enough to heat your house for about 1000 years.” He closes a switch. Between the giant electrodes there leaps a blue-white bolt that builds up into a mighty orb of in- candescent fire as the electric current blasts into the atomic structure of the helium. Even through the tinted glass the glare is almost blinding. The operator does not look up. His eyes are fixed on the dial of a split-second clock on the control board. Suddenly he pulls open a switch. The glare and crackling cease. ‘In three seconds,” he says, ‘“‘we’ve made enough power to drive the old Mauretania around the world a dozen times!”’ HAT would happen to the power generated by this man-made sun? Some of it, in the form of electricity, could be transmitted over high-tension lines to run railroads and operate factories in distant cities. A portion of it might be used to warm houses and office buildings perhaps thousands of miles away. In the form of a liquid, giant liners could use it as fuel for their trips across the sea. Most of the recognized savants of the scientific world agree that the breaking down of the atom will result in the genera- tion of an incalculable flood of power. Chained by the mysterious attraction that holds each electron in the orbit of the nucleus of its own particular atom, there is enough power in a cup of water to pull a 40-car freight train from New York to San Francisco and back a dozen times. Atomic disintegration offers wonderful possibilities of cheap power, of power concentrated into such a small space that the contents of a medicine vial would drive. the airship Los Angeles over the North Pole and back to her hangar, of power of such marvelous potency that a single-tank car would provide fuel for our navy for a long war. , If Professor Perrin, aided by the new 10,000,000-volt generator, is able to dis- integrate even a few of the elusive atoms, he believes that he will at least have blaze1 a trail leading toward a permanent source of heat, light, and power that will revolutionize almost every phase of modern civilization. Why are women afraid of lightning? DO YOU KNOW all the strange fact. about lightning—what causes rains, torps does, cyclones, and all the other terrify; tricks of the atmosphere? Get your ca to-day of a great new book— OUR WEATHER What makes it and how to watch it This useful book, written by the noted authority on Meteorology, Charles Fitz. hugh Talman, explains to you the whol wonderful Science of Atmosphere—hoy fg know when rains and storms are comi how to make your plans without fear of the weather. At bookstores—or send us $3, REYNOLDS PUBLISHING CO. INC.,, 250 Park Avenue, New York City. I enclose $3.00. Send me “Our Weather,” by return mail. * Adress. «6 5 5605s 5 010101010/0:0100 019610 5 6 6 010)s Sa 3525-OW0-y —— SELL,FOOT 7 q COMFORT | Many of our men makeit; $ so may you—selling “World's Greatest Foot- Comfort Shoes’’ direct to Sell on sight. — Low priced. Give real comfort, Great for semi-sport, scuff or general wear. Just take orders; we mail shoes direct. Big cash prof- every state. Territory protected. Live wires soon advanced. Best season NOW. Write Dept. 233. men and boys everywhere. a Day long wear. Shoes or oxfords. it on every sale and repeat. Thousands worn in EAS Y-WEAR SHOE CO., INDIANAPOLIS, IND. Establish yourself as a Photographic Expert uickly—during your spare time—under a eading photographer. 1’ll show you how to startyour own business—orcommanda large salary. Send for my unusual offer—It’s only temporary. Actatonce. A postal will do. International Studios, Inc., Dept. 1367 “Ag 3601 Michigan Avenue, Chicago, U.S.A. “™ i ARITHMETIC oF ELECTRICITY A practical treatise on electrical calculations _ of all kinds reduced to a series of rules, of the simplest forms, and involving 0 ordinary arithmetic. 200 pp. Price, $1. POPULAR SCIENCE MONTHLY 250 Fourth Avenue :;::; NEW YOR See— the big Prize Off on page 4 of th issue. STUDY «* HOME| ‘ , trect ad oy The Aniversity of Chica Courses in English, History, Chemistry, Busines, |” This Mathematics, Education, Psychology, and 35 } subjects command credit toward a Bachelor di Begin any time. Address 25 Ellis Hall, University Chicago, Chicago, III. Everything in Radio| WRITE FOR CATALOG—FREE | RANDOLPH RADIO CORP.) 159 N. UNION AV. Dept. 3 CHICAGO, ILL. | © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

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Own Your Own Electri ee ) , REPAIR SHOP

Boss Electric Construction Jobs |

fart Dopamine, Train AtHome a. ey =Slforaftine wey ————_—_ A Go into ELECTRICITY ! muee7/ . wa ELECTRICAL tone Be an Electrical Expert. Go into the one great in- dustry where it’s easy to get to the top, to make money, to make a real success. You don’t need money in the bank or “‘pull’’ to get ahead in Elec- tricity—all you need is training, honest, complete training, such as I guarantee. BIG JOBS OPEN Everywhere! Look at the building business. Thousands of Electrical Contractors are getting rich. Their men are making $10 to $20 a day. Look at the fortunes being made tn Radio. Look at the great factories building every kind of Elec- trical machinery. Why, the work of the world is being done by Electricity and the call for trained men exceeds the supply! If you’re now earning less than °40 a week —if you want to be an ELECTRICAL EXPERT—if you want to step quickly into the class of men earning from $60 to $250 a week—write me at once! This million dollar school offers ambitious fellows their big opportunity to learn every branch of Electricity at home in spare time by a new, practical JOB-METHOD. Learn Electricity Quick by Dunlap “‘Job-Method” My training so simple a school-boy can grasp it instantly. Common school- JOB SERVI CE indi you need. No previous experience required. ~~ my ee — At No Extra Cost to rapid progress because I train them on actual Electrical jobs with standard- size tools and materials which I supply without extra cost. The first half of STUDENTS and GRADUATES my training is APPLIED ELECTRICITY—a complete course in itself. jobg, not only to graduates, but > ae 5 : : tao anbhiects ive you. NTS also. This JOB- In the second half I give you Electrical Engineering subjects. I give you pate cease in bak ae great Electrical employers all over

Electrical Drafting, Radio, Automotive Electricity, and many other valu- ce a) able subjects, all for one small price, and on easy terms. America. The day you enroll, iy . ‘J ; ean: | tas ven tees et ee ee alculations ‘ j 4 Train for These Jobs THESE Ps | ee creas job you want, where you want to rules, all : i ml at : Power Plant Superintendent, $5,000 0 work, etc.

P 5 . 2 And when you apply for the ving oO oe BB. to $15,000 a year; Construction to you without one penny of extra job you want, we back you with ice, $1.50, _— : Ry trical Repair Work, a better job and bigger pay. I FOR PROFIT. Established 29 years. Over 2(0 gi P Pm sm - ae ~~ etc. I show you’ willanswerthatin plain Eng- Executives, Engineers, and Educators have prepared how to get spare- lish. Get my catalog, my won- the texts used in these wonderful home-study courses. time work— § derful new guarantee, my sen- The success of our graduates has made us one of the \ ‘ Training Built b . 3 ~ Work Oud gational offers—quicki Get the largest VOCATIONAL TRAINING Institutions in 23 NOTED ’ © e™, Oe . — paid facts about your opportunities the world. You will be astonished at the many ways : year; Chief Electrician, $3,000 wo “RRER” * -e you to en- make good in it after you get it. [ONTHL 4 : , \ to $12,000 a year; thing ‘‘FREE”’ to induce yot

. in Electricity when you are we help our students and graduates progress to success, ENGINEERS % . Dunlap-trained and when you : : i t have the backing of the Ameri- This is not a one-man, one-idea school. o can School. Before you enroll ‘a? 2 22 famous Engineers and Executives of ®& * for any home-training, get the r . 7 e following corporations and unive facts about my training, so you 2 i! ‘ p- —~ can compare it intelligently A, > Fue

sities helped me make Dunlap-training the ith I Wai with others. Write me today! most complete and up-to-date: ra dy 1. General Electric Co. 7. Western Electric Co. te Se prison. maar: ng - Commonwealth Edi- 8. Underwriters Labora- ( AMERICAN SCHOOL, Dept. E-775 ison Company tories, Inc. an 3. Crocker-Wheeler C 9. Columbia Universit M. N 700A, * Drexel Ave. & 58th St., Chicago ¥ =. ©. - Columbi er : 4, Cutler-Hammer Mfg. 10. Sastanentie Callees” ‘ Al L COUPO I want to be an Electrical Expert. Please P Company 11. Massachusetts Insti- ; a ¥ rush guarantee, job-service facts, complete .h 5 Telephone 12 fute ~ | ee : gnhe ° information, money-saving offers. aph Co. 2 i i it : . : 6. Westinghouse Electric 13. University of Vermont Chief Engineer Dunlap, Electrical Division i414 & Mfg. Co. AND MANY OTHERS Name. Ack any well posted Electrical Engineer about the A M ERI CA N SCH 0 0 L re O R p, t training ng Ree of AMERICAN SCHOOL home- Dept. E-775 AGO, ILL. 5 Drexel Ave. & 58th St. CHICAGO © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. Street No

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So. Svs on ara pera Raham oi Drawn 2 mle actual photoeraph of preint doing spare time electrical work a Hkctricity Mal¢ Bis Money How would you like to earn two or three dollars every evening after school and pre- pare e yourself for a fine big job at the same time? ere’s the oDportunity of a lifetime for you fellows who like Electricity. Begin right now to prepare yourself for a regular man’s size job in this fascinat- ing field. Your chances for a dig success are simply wonderful—the pay is big (thousands of men earn — to $200 a week) and advancement comes swift @nad sure. f will Train You at Home With my easily learned, sparetime Electrical Course I will train you at home like Ihavetrained hundreds of other boys who are now big successful men. It will not inter- fere with your school work an a you can earn more thanthesmall y cost of the course doing odd elec- Is Doing trical jobs in your spare time. The “Although the Course paysforitself.I willshow [| School term is com- you howtogetthis work and how | !2s toa close, and I odoit. Some of my boy students | °™ brett, busy" ag a $10 to $15 a week this way. Tools, Apparatus and | ,, i Radio Course Given | 2 pusiness for my- Without Extra Charge | >rtove ital! tovou. Send me the coupon below andI will tell you all about the big out- fit of tools, apparatus and instru- 4 ments and a new Radio Course | bave all the work 1 that Iam giving to my students | {2yce-sverssings2 for a limited time, I willsend you | spate time work. my big interesting Electrical | job‘toniehtafres k and a sample lesson, too— | school, on which all Free. You willbetickledwith | Pade3sodbrought the things I willsend you Free, | which a Emado $3.60- -50— "Kjb, COOKE, Chet Eng aaa! sare . Tate Chestnut St., Dept. 0-37 CHICAGO Greenville, N.C: October, 1935 Use This ‘FREE BOOK” Coupon L. L. COOKE, Chief Engineer, Chicago Engin Works, Dept. 0-37, 2150 Lawrence Ave., Chicago Send me your Big Outfit Offer, your big Electrical Book, Sample Lesson and particulars of your Electrical Course and Extra Radio Course. This 1 not obligate me in any way. I EC ESE 8 oi ss wis wae ip ieee bio 60 8 Sie 30 This Coupon only for use of boys 15 years old or more. ee LAW. Bask Write today for FREE @ book, “THE LAW TRAINED onan 2 which shows how 5o fone: fn your enero came a8 yfora or vt prepare to mone.” quality for of law. Study at he at hom 3 ges ae Sane the Blac! rominent | tles Liam HOWARD Houdini—The Man (Continued from page 17) “And,” continued Houdini, speaking most emphatically, “there is just such a natural and physical explanation for every trick, every illusion, every ‘psychic phenomenon,’ every ‘supernatural mani- festation’ I have ever seen. There may be genuine psychics. There may be spirit- ualistic mediums who actually can estab- lish communication with the dead. There may be those who can transfer their thoughts directly to the minds of others. On these points I have an open mind; I am willing to be convinced. All I can say is that I have combed the world over in search of those who can perform such wonders without trickery—and have failed to find them.” _—o do you devote so much of your stage performance and so much of your own time to exposing fraudulent mediums?” I asked. “For several reasons,” Houdini an- swered. “In the first place because the investigation of psychic phenomena in- terests me. It’s one of my chief hobbies. I have studied and investigated psychics, mediums, and other supposedly super- human wonder workers for 35 years in all parts of the world. I have learned their tricks and have found them good theatri- cal material. “Besides, in the public forum which I conduct at each performance of my stage work, the questions I am asked by the audience indicate that the public is more keenly interested now in spiritualism than in any other phase of occult manifesta- tion. The questions that come to me through the mail likewise show tre- mendous public interest. “And, although I mention it last of all, my chief reason for exposing the tricks of fraudulent spiritualists is because I be- lieve that by so doing I am performing useful public service. There are through- out the world many mediums and other kinds of self-styled psychics who are using trickery to prey on deluded or grief- stricken persons under the guise of re- ligion. Their victims number thousands. Millions of dollars have been taken by them from their dupes. Knowing their tricks from my own personal observation and experience, I consider tt my duty to warn the public against them. That is why I have been so active of late years in exposing fraudulent mediums. It has cost me much in money and time, but my crusade has repaid me mightily in the satisfaction of knowing that I have re- duced materially the number of these vultures by exposing them and their methods. HERE is, of course, a legitimate use for trickery. When other magicians and I employ it to entertain and amuse, we are performing a useful service, quite as much as are musicians, dancers, and other stage folk. The skill with which we Books on Electricity The Electrician’s Wiring Manual By F. E. SENGSTOCK, E. E, Contains all the information needed for the proper installation of lighting and power systems in houses and other buildings. It completely covers inside elec- trical wiring and construction in accordance with the National Electrical Code. 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The simple directions and many mystify has been acquired by long, pa- tient, arduous practice. We must prac- tise continuously and forego many of the pleasures of life in order to retain our skill. Thus, I have never smoked nor drank. I hiseanite 2 on page 155) drawings make the work easy. | 429 pp. Price, $1.50 postpaid POPULAR SCIENCE MONTHLY 250 Fourth Ave., New York City © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. met oer tric] 1 plie prol the tric] is lo wat mys ing- iron “co that exal ferv tric! is al goir tric] nent time nari and som suc feet foot por .} ceec wor frar to « stre neal tere squi aliv last perf e; ‘end tric] ale lect: gan acce ups ——

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Houdini—-The Man (Continued from page 154) lead the rigorous life of a pugilist in training. As the contortionist said, ‘I must starve myself to do my work, and I'll starve if I don’t work.’ se . “You're convinced, then, that all psychic henemena are produced by trickery?” “A}l that I have seen,” said Houdini; “and I’ve searched far and wide for genuine manifestations. For years I’ve offered as much as $10,000 to any medium, yehic, or seer who could produce a physical manifestation of his boasted power that I could not reproduce by natural means. I’ve had some challenges _—put I still have my $10,000. I wish,” he added with a smile, “that some medium would make me a counter offer on the same terms—to reproduce by his methods a trick that I would perform by mine.” “What do you consider your best trick?” I asked him. “fT SHOULDN’T care to select any single trick as my best one,” he re- plied thoughtfully. “My four best, though, probably are the disappearing elephant, the Chinese torture chamber (this is the trick, described above, in which Houdini is locked in the metal cylinder filled with water), the needle trick, and permitting myself to be shackled, nailed into a pack- ing-case weighted with 500 pounds of pig iron, and thrown overboard.” “You say you perform all these feats by trickery,” I said. “Does that mean that when you’re thrown overboard, for example, you’re in no physical danger?” “T’ll say it doesn’t!” responded Houdini fervently. “Of course, I perform no tricks without rehearsing them; yet there is always the danger of some little thing going amiss and not only spoiling the trick, but spoiling me as well—perma- nently. The former has happened several times, and as a result I’ve had some very narrow escapes. “T permitted myself to be shackled hand and foot and buried alive in California some years ago. I had previously escaped successfully from graves from one to five feet deep, but when I was placed in a six- foot grave, I lost my self-possession tem- porarily. As a result, instead of pro- .| ceeding calmly and carefully about the work of freeing myself, I began to struggle, frantically and aimlessly, and I attempted to call for help. My efforts sapped my strength; my attempts to shout caused me nearly to be suffocated. Luckily I mas- tered myself in time, and managed to squirm to the surface more dead than alive. And if it rests with me, that is the last time that particular trick ever will be performed. “ ANOTHER time, I nearly brought my career as an entertainer to a sudden ‘end by doing the Chinese torture chamber trick in a cask of ale. The fumes of the ale intoxicated me, and I have no recol- lection to this day of completing the trick. “In Buffalo, N. Y., several years ago, a gang of longshoremen from the lake front accepted my challenge to any one to tie me up so that I could not escape. They came

(Continued on page 156)

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fae cgetes ties er mos lent to whic Over 4 NO Dept. on of free Atl 7 Name 1925 ATLAS With Maps ./NewEurope To readers of this magazine who take ad- vantage of this offer now made in connection i “Webster’s New International I re G. &C. : MERRIAM CO. Please send me free of all obligation or ex, : of **Dictionarv Wrinkles’’ ning an wee ne * Test ; in Pronunciation ” (with kev) entitled “‘The Americaniza- . references to their answers and striking ‘‘Facsimil Golor-Plate’” of the new bindings. Please include speci, men pages of Ind a and Regular paper with terms of your ary to POPULAR SCIENCE readers. The Merriam Dictionary ‘"wec:” The “Supreme Authority”’ A complete reference library in dictionary form, with 3000 pages and type matter equiva- a 15 volume encyclopedia, allina single volume, can now be yours on the following remarkably easy terms: The entire work (with FREE 1925 Atlas) DELIVERED FOR $1.00 ; and easy monthly_payments_ thereafter (in United States and Canada). 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See page 6. opportunity to get uarantee, JobServ- to the Houdini—The Man (Continued from page 155) theater armed with the chains, cables, and other apparatus they used in loading cargo on steamers. I thought I had seen about everything in the line of bonds and shackles, but those fellows produced a brand new assortment! I managed to free myself eventually, but I have never forgotten the experience, for a heavy chain that they tightened about my waist with levers crushed one of my kidneys, necessitating my sleeping with a pillow under my back ever since. B iad BERLIN, Germany, once, a man walked to thestage, and produced from his pocket a small, glittering object. I shuddered when I saw it, for I recognized it as what is called a ‘thumbcuff.’ This is a particularly devilish sort of handcuff, consisting of a small plate about three inches long by an inch wide, with two cir- cular holes, each just large enough to admit one of the thumbs. This is slipped over the thumbs to the second flange. Then a nut at the side is turned, and circles of small steel pins, each ground to a needlepoint, close about the thumbs. Any movement of the hands causes these needle points to tear the flesh. Obviously if one attempts to pull his thumbs free, the flesh about the joint and the thicker upper flange will be lacerated cruelly. “Well, having challenged the City of Berlin to produce anything it could in the way of handcuffs, I had to let the man put the thumbcuff on me. Also, I had to escape if I could. “It was one of the most painful ex- periences of my career. The spikes pen- etrated to the bone, and the bleeding flesh hung in strips from my thumbs when at last stage. greeted I dropped the thumbcuff to the Never has one of my tricks been by more tumultuous applause than came to me for this demonstration, which actually was not a trick at all. And when I left the theater, I found myself surrounded by a cheering crowd that raised me to its shoulders, and then un- hitched the horses from my cab to draw me in triumph through the streets of the city. “Once, in the middle of winter, I per- mitted myself to be shackled hand and foot and dropped through a hole cut in the ice into the Allegheny River, near Pittsburgh, Pa. In prospect there was nothing terrifying about this feat. I have always been astrong swimmer, accustomed to taking my dip winter and summer. I had made hundreds of water handcuff and rope escapes; so when they dropped me into the hole I was quite as calm as though merely going through my stage routine. se: OWEVER, I had failed to take into consideration one tremendously im- portant item—the swift current of the river. stream, As a result, I was carried down- and when my body rose I was under the ice, which was several inches thick. I had no idea where the hole in the ice was located, I could not, of course, cut another hole through the ice; nor was there any way in which I could signal my plight to those who were waiting for me to emerge. (Continued on page 157) It is a poor week when Earl Hatfield doesn’t makemorethanthat inhis garage. At19yearsofage,a farmer boy, hecameto Detroit the , Auto Center, and learned the auto bus, eee at this great School. Now he has a fine busi. ness near his home, ismarried, independen; making good money. He is just one of man; who havedone the same. These succesgfy] Michigan State trained men are just plain H fellows, no brighter nor better educated than you. Practical training at the factory endorsed school started them to success, g Make Big Money Too The auto business offers unlimited opportunities, Think of the repair work on 18,000,000 cars, There are not nearly enough trained men to do this work, You canbeaskilledmechanic and autoelectrician and Earn, Big a Experience isn’t necessary. If you are mechanically inclined come to Detroit now, to my school. Become atrained man and go back toyourhome town. If yourun a farm you can increase your p Or work asa mechanic, or start a garage of your own, Learn Autos In Detroit The Heart of the Industry B Here you have wonderful advantages. Study autos, trucks, engines, auto electricity, tractors. All on best equipment, up-to-date,many new cars; expertinstruc. tors; a thorough course that slights nothing. Inspect the great auto plants. These great companies approve this A school.Get factory endorsed training at Detroit, theAutoCenter GOOD POSITIONS OPEN. Here’s your chance to be inde. pect nate today for full osteo Detroit train. . ng to make the most money. . G. Zeller, Michigan State Automobile Schooj 339 Auto Building Detroit, Mich, L. Ee ie = fa - E © Drawing Easily Learned Haven’t you often wished that you could draw cartoons, illustrate some idea, sketch some pretty face, etc? You can do all of these things. One ot America’s most fa- mous Cartoonists_and Illustrators has developed a great, simple system for success in all branches of Commer- cial Art. This system has revolu- tionized the entire theory of draw- ing. It means that drawing can be as easy for you as writing—much simpler than learning shorthand, bookkeeping or typewriting. We are now placing this original system for learning Drawing, Art and Cartooning, consisting of 34 lessons with over 500 illustrations, within reach of every one. If you will devote a few hours each week to the Course WE ABSOLUTELY GUARANTEE that you will learn to draw_and draw well before you have half finished the Course. If we fail to make this claim good, we will refund every cent paid us. By eliminating a large office force for answering corre- spondence, expensive catalogs, etc., we are enabled to make a price of $2.98, the cheapest price ever known for a high-grade, home study course. Many have sent us letters similar to that of Rob’t P. Davis of Detroit, who wrote: ‘‘I can’t see how you ask so little when others with inferior Courses get from $20 to $0 for theirs. It is more than I expected.’”’ Learn to draw, It is a big asset, no matter what field you are in. If you order the course at Send No Money ence, we will include a Just order the Course, and on arrivil drawing outfit, consisting Day postmanonly . . , of artist’s pencils, pens, plus a few cents postage, $2.98 paper, erasers, thumb payment in full for the tacks, etc., enabling you entire Course and Drawing Ontit ts 0 to work — any ss not entirely getished, ec additional cost. ive days and we will MONEY. Address: LEDERER SCHOOL OF DRAWING, Dept., 216-C, Chattanooga, Tem. Orders from outside the U. S. are payable $3.24 cash with order e a Y your neighbor praise the ° old reliable Pathfinder, the wonderful national weekly home magazine that 3 million people read, You can try this unbiased digest of domestic and world affairs for a tt fle. The Pathfinder is in a class by itself—nothing else to equal It; time-tested, wholesome. Chuck full of the choicest reading- cream of everything. Science, politics, travel, fun, question health, radio etc. ;real stories, pictures—instruction, enterta for all. Send 15c (coin or stamps) for this big paper on trial 13 weeks’ or $1for full year (52issues), Pathfinder, Washington, D. Secure Better Hlustrations USE AN ALL METAL for roughouts, layouts, e! seal le sy, ch proportions, etc. Bi ple Adjustable Permanent Economical Sent postpaid on receipt of only Money refunded if not satisfactory: DRAWING-AIDE CO., 207 Caxton Bidg., Cleveland, 0.

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rs. here is work, ‘ian and ya etroit r Alonbet pertinsteas. ung. Inspect tnedutoCast ce to be Inde. Detroit train. ler, Presideg e School troit, Mich, pia: earned uld ch f f Rob’t P. Davis you ask so little rom $20 to $0 Learn to drav, | are in. . Money rse, and on arrivil steac; $2.98 cash with order OF EVENTS You've hearl neighbor praise the le Pathfinder, the nal weekly people read, You rid affairs for 8 tr- ng else to equal it; icest reading- fun, question bor, ion, enterta! sr on trial 13 weeks shington, D.6 layouts, e! tions, ch , Cleveland, 0. ——— me Houdini—The Man (Continued from page 156) “My only hope of saving myself lay in finding the hole through which I had been I don’t believe I ever did so t and serious thinking before or yy ~ swiftly as I could, I released one of my hands. Then I began moving ground in circles, dragging my body along by digging the handcuff on the other wrist into the ice above my head. Grad- ually I made my circles larger, and at jast reaching upward, my hand touched the edge of the hole. Seizing this with the other hand, I anchored myself ; then went about my work of releasing myself from the remaining bonds. “A few seconds later I climbed out of the water to face a white-faced, frightened group of persons who, because of the length of time I had spent in the river, were ready to give meupfor lost. And to this day they have never known how nearly right they were! “rf HAVE had many other similar ex- periences, but those I have described probably will suffice to show that a man who does my kind of work does not always tread a path of roses. “However,” added Houdini, with a meaning glance around his library, “there are. compensations.” And as I followed his glance I was con- vinced that there were. Houdini’s hand- some home, his marvelously stocked book- shelves, his art treasures, are unmistakable tokens of material success. The auto- graphed photographs of celebrities that line his walls are indicative surely of the esteem in which he is held by the leading men of his generation. The fact that the Society of American Magicians nine times has elected him its president is proof conclusive that present- day magicians acclaim him “‘master.”’ He has the love of a devoted wife. He has earned the leisure to indulge himself in the research and study that are his pas- sion. Every man, woman, and child in the civilized world undoubtedly knows his name. With what other gifts could Fortune shower a man? JN THE first of his extraordinary series of stories for POPULAR SCIENCE MONTHLY, Houdini will relate in next month’s issue some of his dramatic experiences in expos- ing fraudulent mediums. He will tell how, by employing ingenious tricks of the magician, he has laid bare the trickery of unscrupulous "persons who prey on deluded thou- sands. Houdini’s own story is full of ex- citing action and romance. You will not want to miss a single in- stallment of this amazing series. To avoid disappointment, order your copies of the magazine from your newsdealer in advance. To DRINK, or not to drink—with Dr. A. C. Ivy, a University of Chicago physiologist, says “go ahead.” Drinking Water produces more complete digestion stimulation for the gastric glands, he Maintains, and permits more complete absorption of food into the blood stream. meals—has long been an open question. 157 Nerves by PAUL von BOECKMANN Lecturer and Author of numerous books and treatises on Mental and Physical Energy, Respiration, Psychology and Nerve Culture E are living in the age of SPEED, the mile-a-minute life. We crowd two or five years of life into one. We hurry; we worry; and we dissipate, little realizing that there must come an end to our supply of Nerve Force—that we will become nervous wrecks. Long before a person reaches the final stages of nervous collapse, he passes through months and even years of sub- normal nerve power, which seriously handicaps him in life, undermines his con- stitutional powers and causes all kinds of organic and mental -disorders. It would be proper to call these people “near- neurasthenics.” There are countless “near-neurasthen- ics” about us everywhere—in the streets, in the cars, in the theatres, in your busi- ness, and especially in your own home— right in your own family. They are said to be troubled with “nerves,” a condition which is not con- sidered serious, but admitted to be most annoying, especially to those who must associate with people who have “nerves.” “Nerves” is not a malady which mani- fests itself, as many people believe, in twitching muscles, trembling hands. These conditions are found only in ad- vanced stages of Nerve Exhaustion. The symptoms of Nerve Exhaustion vary according to individual characteris- tics, but the development is usually as follows: First Stage: Lack of energy and endurance; that “tired feeling.” Second Stage: Nervousness; restlessness; sleep- lessness ; irritability; decline in sex force; loss of hair; nervous indigestion; sour stomach; gas in bowels; constipation; irregular heart; poor memory; lack of mental endurance; dizziness; headache; backache; neuritis, rheumatism, and other pains. Third Stage: Serious mental disturbances; fear, undue worry; melan- cholia; dangerous organic disturbances; suicidal tendencies ; and in extreme cases, insanity. If only a few of the symptoms men- tioned apply to you, especially those in- dicating mental turmoil, you may be sure that your nerves are at fault—that you have exhausted your Nerve Force. Perhaps you have chased from doctor to doctor seeking relief for a mysterious “something the matter with you.’’ Each doctor tells you that there is nothing the matter with you; that every organ is perfect. But you know there is some- thing the matter. You feel it, and you act it. You are tired, dizzy, cannot sleep, cannot digest your fo and you have pains here and there. You are told you are “run down,’’ and need a rest. Your doctor may prescribe a drug—a nerve stimulant or sedative. eave nerve tonics alone. It is like making a tired horse run by towing him behind an automobile. And don’t be deceived into believing that some magic system of physical exercise can restore the nerves. It may develop your muscle but it does so at the expense of the nerves, as thou- sands of athletes have learned through bitter experience. The cure of weak and deranged nerves must have for its basis an understanding of how the nerves are affected by various abuses and strains. It demands an understanding of certain simple laws in mental and physical hygiene, mental control, relaxation, and how to develop immunity to the many strains of everyday life. Through the application of this knowledge, the most ad- vanced case of Nerve Exhaustion can be cor- rected. I have made a life study of the mental and physical characteristics of nervous people, having treated more cases of “Nerves” during the past 25 years than any other man in the world; over 100,000 cases. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. PAUL VON BOECKMANN ; Author of Nerve Force and various other books on Health, Psychology, Breathing, Hygiene and kindred subjects, many of which have been translated into foreign languages. The result of this vast experience is embodied in a 64-page book, entitled “Nerve Force,” a book that is essentially intended to teach how to care for the nerves and how to apply simple methods for their restoration. It includes im- portant information on the application of deep breathing as a remedial agent. The cost of the book is only 25 cents, coin or stamps. Address me—Paul von Boeckmann, Studio 169, 110 West 40th St., New York City. This book will enable you to diagnose your troubles understandingly. The facts presented will prove a revelation to you and the advice will be of incalculable value whether you have had trouble with your nerves or not. Your nerves are the most precious possession you have. Through them you experience all that makes life worth living, for to be dull-nerved means to be dull-brained, insensible to the higher phases of life—love, moral courage, ambition, and tem- perament. The finer your brain is, the finer and more delicate is your nervous system, and the more imperative it is that you care for your nerves. “Nerve Force” is not an advertisement of any treatment I may have to offer. This is proved by the fact that large corporations have bought and are buying this book from me by the hundreds and thousands for circulation among the employees—Efficiency. Physicians recommend the book to their patients—Health. Ministers recommend it from the pulpit—Nerve Control, Happiness. Never before has so great a mass of valuable information been presented in so few words. It will enable you to understand your Nerves, your Mind, your Emotions, and your Body. Over a million copies have been sold during the past fifteen years. What Readers of “Nerve Force” Say: “I have gained 12 pounds since reading your book, and I feel so energetic. I had about given up hope of ever finding the cause of my low weight.” A physician says: “Your book is the most sensible and valuable work I have ever read on the prevention of neurasthenia. I am _ recom- mending your book to my patients.” “Reading your book has stopped that dreadful feeling of FEAR which paralyzed my stomach and digestion.” “Your book did more for me for indigestion than two courses in dieting.” “My heart is now regular again and my nerves are fine: I thought I had heart trouble, but it was simply a case of abused nerves. I have re- read your book at least ten times.” “The advice given in your book on relaxation and calming of nerves has cleared my brain. Before I was half dizzy all the time.” “T have been treated by a number of nerve specialists, and have traveled from country to country in an endeavor to restore my nerves to normal. Your little book has done more for me than all other methods combined.”

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“The Boss Didn’t Even Know My Name” “He said my face was more or less familiar and he remembered seeing me around, but he didn’t even know my name until the I. C. S. wrote him that rge Jackson had enrolled for a course of home study and was doing e work. “‘*Who’s George Jackson?’ he asked. Then he looked me up. Told me he was glad to see I was ambitious. Said he’d keep his eye on me. “He did too. “Gave me my chance when Frank Jordan was sent out on the road. I was promoted over older men who had been with the firm for years. “My spare-time studying helped me to get that job and to keep it after I got it. It certainly was a lucky day for me when I signed that I. C. S. coupon.” How much longer are you going to wait before you take the step that will bring you advancement and more money? It takes only a moment to mark and mail this coupon and send it to the International Correspon- dence Schools at Scranton. Isn’t it better to do this today than to wait a year or five years and then wish you had? Mail the Coupon for Free Booklet INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7669-D, Scranton, Penna. Oldest and largest correspondence schoools in the world Without cost, please tell me how I can qualify for the position or in the subject before which I have marked an X: BUSINESS TRAINING COURSES [Business Management (Salesmanship Industrial Management (J Advertising Personnel Organization LoBetter Letters [| Traffic Management CL) Show Card Lettering [| ]Business Law CJStenography and Typing [ ]Banking and Banking Law CiBusiness English |) Accountancy (including C.P.A,) LU Civil Service i () Railway Mail Clerk Nicholson Cost Accounting Bookkeeping Common School Subjects Private Secretary High School Subjects LJ Spanish French Illustrating TECHNICAL AND INDUSTRIAL COURSES OElectrical Engineering [) Architect OjElectric Lighting (J Mechanical] Engineer () Mechanical Draftsman {) Machine Shop Practice (J Railroad Positions Gas Engine Operating (J Civil Engineer Surveying and Mapping Metallurgy () Mining Steam Engineering [1 Radio | jArchitects’ Blueprints [ }Contractor and Builder _j Architectural Draftsman [ |Concrete Builder Structural Engineer Chemistry () Pharmacy | JAutomobile Work |) Airplane Engines [j Agriculture and Poultry [J Mathematics Street Se CE et ET TEE pe debrtens arberiny pitacokcsctsagis If you reside in Canada, send this coupon to the Interna- tional Correspondence Schools Canadian Limited, Montreal PATENTS Trade-marks, Copyrights, Patent Litigation. Handbook with illustrations, 100 mechanical movements. Sent free on request. ALBERT E. DIETERICH Formerly member Examining Corp. U.S. Patent Office Patent Lawyer and solicitor. 27 years’ experience 681-A Ouray Bidg., Washington, D. C. PATENTS BOOKLET FREE HIGHEST REFERENCES PROMPTNESS ASSURED BEST RESULTS Send drawing or model for examination and report as to patentability WATSON E. COLEMAN, Patent Lawyer 644 G Street N.W., Washington, D. C. Inventive Genius on the Gridiron (Continued from page 11) lined with felt and harnessed together fore and aft with straps, also lined with felt, and so on. Also, certain imagi- native gentlemen tacked on other utili- ties to fit their own particular style of play. Fok instance, Harvey Woodruff, who made Pennsylvania famous with his “guards back” formation for rending an opposing line, happened on a bright idea for promoting cohesion in his particular style of attack. His contribution was a set of handles, much like the handles on an ordinary flatiron, except that they were made of several plies of canvas, securely sewed on the hips of the players’ pants. When the attack was launched, the man carrying the ball grabbed a handle on a lineman ahead, the other backs grabbed the runner in like manner, and there was a merry pull and haul. It was permissible to push and drag a man along in those days as long as you could keep going. But the introduction of the forward pass with a more open game, brought corresponding changes in equipment. More and more of a premium came to be placed on speed and agility, and it was found logical to dress the part. Away went nose guards and, in a good many cases, headgears as well. The urge for speed also prompted lighter dress. The old moleskins that had soaked up water like a sponge on a rainy day, gave place to the canvas of the earlier days. HEN came “Pop” Warner with another of his clever ideas. Warner decided that the extra weight represented by several gallons of water soaked. up by the men’s clothes on the field was an unnecessary handicap. After consider- able experimenting, he found a kind of leatherette material that appeared to suit his purpose. This he took to a well known firm of sports equipment manu- facturers. The firm agreed to make a few sample pairs of breeches, and the spacious form of “Pop” himself was taken as a model. When the samples were finished, they were shipped to Warner at his farm near Buffalo, and there he gave them their first actual test. He scooped out a big hole in the ground, spaded up the dirt, and then ran it partly full of water, forming a fairly close ap- proach to a first class hog wallow. Then he donned the new garb and sloshed around in the mud until the pants were thoroughly covered. After this, he turn- ed a hose on them and, presto! in a minute they were thoroughly clean and apparently no heavier than when he first put them on. With his team equipped with these “leather britches,’’ all a coach has to do nowadays between halves of a game on a rainy, muddy day, is to have his men strip off their jerseys, turn a hose on them, provide them with clean dry jerseys, and send them back to the field in as good trim as they were when they started the game. (Continued on page 159) EARN UP TO $250 .E% "om MEN WANTED! Advancement rapid with experience A profession with big opportunities. Pleasant. outqn smd Travel or remain near,home. Report to high railway one POSITIONS OPEN—MUST EE FILLED We secure position for you, upon graduati ; a least $110 per month and expenses or refund op ovine a You can easily prepare in 3 mos. spare time home etn Hundreds of successful graduates. Mail coupon tod i il kn —— ma Standard Business Training Inst., | Buffalo, T. ” Send me, entirely free, Booklet No. D-64, giyj particulars about course in Railway Traffic Inspesie | Street. ..... Can Bea Dental! YOU Laboratory Expert Make Up to $150 a Week BOTH MEN AND WOMEN IN DEMAND PERSONAL INSTRUCTION to Each Student T=] In One Big Sch echanl. Bee cal Dentists. “The onh )- of Stivison Trained Graduates {iva Jobs Hunt You. Every t does Laboratory Work that he would gladly have done by ap Expert and pay Big Prices, Real Dentist’s Tools are furnished and Instructions given by Real Dentists on work that Dentists need. Descriptive illustrated Book Free. We hep aes Fare to Kansas Gy and assis 0 i tuition, Earn “while you, ay GET IN THE BIG PAY CLASS Write for Special Offer. Delay may cost you a good job and lots of money, Stivison Dental Institute 500 McMillen Bldg., Kansas City, Mo. Experts Earn $75 to $200 a Week H Right now, everywhere, big, easy money is being made in Field unlimited. You can master Radio quickly at home in spare time. No previous experience ne / F essary. Now is the time to enter” Wi J. this new, uncrowded field. —=~ 1,000 Mile Receiving Set i Our new home-study methods g With the Course everything about radio amazingly simple. No other course like it. Makes you expert of radio operation, repairs and installations of all kinds, Send for literature telling all about opportunities and how we give 1,000 mile receiving set with the course. Don't miss this big offer—ACT. Write now for big free Radio Association of America 4513 Ravenswood Ave. Dept.41 Cc TECHNI COLLEGE > Ca Repair 2 do it east These FI automobi little kno repairs. Taste clear an most int ever writ Whether repair ex your ow! splendid! 1 An amaz books to payment ship the read thet photogra you wan month u ing mort include Cons Yes, we titles yé related experts ; help you member: {22nd YEAR J Intensely practical training in Drafting and neering—civil, mechanical, electrical, struc —Architecture.2 year Diploma;3 year B.S. Degree special short courses. Courses adapted to yourneed No time wasted. Instructors are experts. Our ates are in constant demand. Opportunities for p: time work while studying. Day and evening class Athletics. Enter anytime. Low tuition—easy te Write for 52-page illustrated Blue Book, descri opportunities open to our graduates. Chicago Techt ollege, N-51, Chicago Tech. Building, Chicago, II. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. 6

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Whether you want to fit yourself for garage owner, repair expert or merely wish to know more about your own car, you will realize the value of these splendidly bound volumes. NO MONEY OFFER An amazing new plan of distribution brings these books to you for examination without one cent of payment to us. We don’t ask a penny of you, but ship the books to you FREE. Look them over— read them as much as you want to; note the splendid photographs and drawings and then if you decide you want them, send us $2.00, then only $3.00 a month until only $19.80 is paid. That is all; noth- ing more to pay us. If you send NOW we will include Consulting Membership—INCLUDED Yes, we actually give you a certificate which en- titles you to free consultation on any subject related to automobile repairing. 18 specialized experts are at your disposal—ready at any time to help you. With this library and this consultation membership you ought to be able to soon know all there is to be known about autos. Don’t miss this special offer. Send now. fesse Sg aie aaa AMERICAN TECHNICAL SOCIETY, Automobile Division A720a, Chicago, III. You may send me your complete Automobile Engineering library, 5 big volumes bound in flexo covers, with the understanding that I am to have ten days to decide if I want to keep them. I will either return them then or send you $2.00 then and .00 per month until the special low price of ouly fie'80 is paid. MU Empioyed by Hee a te tae tee a se tm teed fle eed teed fms teed ee met te ed id tet arn when enroll HAWAIIAN GUITAR ax d Case Just as the Natives Do * Easy Lessons fa aptons yor Way me nats ioe wher 0! harmonious chords with the 62 printed lessons very little practice. No and the clear pictures breviousmusicalknowl- make it easy to learn edge necessary, qa » Payas you play. Free Guitar and Outfit in Genuine Seal After you get the four one be at Once roll @8 soon as you one this beautifu ne Regma ; erything W: to furnished. No dels, °” FIRST HAWAIIAN CONSERVATO . 9th Picor, Woolworth Bldg., Dept. 446 Cee «. v. asa Under = of the State of ‘Now Sok ow SUSPORRCCSRORESUOCROSCERESRSERSUSERERAReReReREREEEEES as eee coer ay make ru and robes. Complete | is tmitram teeter Write for Fi ‘axidermy Be Ok. Tells all about it. and Nature lover should fal fascinating art. ow this wonder- Save your trophies. B Investigates "Write for Free Beak. uates, vi School of Terideray, 1202 Elwood Big. Omaha. Neb Inventive Genius on the Gridiron (Continued from page 158) In the open game of today, knees and thighs are the targets for more punish- ment than most any other parts of the player’s anatomy. Knee padding has been in vogue for many years, but it remained for Coach Spears of West Virginia to solve a problem that had puzzled for along time. Former- ly, football pants were so padded at the knees as to place the protection in place only while the player was standing. But much of his time is spent kneeling or crouching down. Spears has devised a shallow leather cup, felt-lined, which is so attached that it covers the knee cap completely at all times. One of the latest and most elaborate appliances for helping in the training of a football team is a tackling apparatus patented by Charlie Moran, National League baseball umpire and coach of the Bucknell eleven. Moran’s invention com- prises an extensive framework from which are suspended dummies in such manner that they can be shifted to simulate the defense of any team that the users may expect tomeet. The arrangement further permits setting the dummies in motion as the team starts its play, so as to have them in the approximate positions to which actual players would be expected to shift. Fok all the sundry protective devices worked out, the game still takes its toll of injuries. At the Kansas State Agricultural College, football players last season were given baths of ultra-violet light as part of their training. This treatment has been especially effective in ridding play- ers of boils, on account of the light’s great power as a germicide. But baths of the light are given these players, too, to build up their strength and fighting qualities, and victory in more than one important contest has been imputed .to the treatment. Recent research indicates that ultra-violet light helps in building up new red blood cor- puscles. With a team battered to pieces, and another game scheduled for the coming week, a way to speed up the manufacture of red blood may decide the score. This innovation of light treat- ments in Kansas is an indication of how coaches are availing themselves of the very latest in scientific research. Ovens for baking out swollen joints, liniments and lotions for removing soreness and the like are all a part of the equipment of a big college team nowa- days. Also, a brace for refractory knees has been devised which will enable a player, who otherwise would be relegated to the side lines, to scamper on the field and cut surprisingly active capers. Yes, and a few years ago, a brace was de- vised that enabled Eddie Hart, hard- plunging fullback of the Princeton Tigers, to rip through opposing lines although he carried a fractured vertebra in his neck. Such necessity-born artifices of science and invention have had quite a hand in making possible the annual thrills on the gridirons throughout the country. IS) This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. “Its me!” “You was ? “Cant hardly’ ~ What Are YOUR Mistakes in English They may offend others as much as these offend you F someone you met for the first time made the mistakes in English shown above, what would you think of him? Would he inspire your re- spect? Would you be inclined to make a friend of him? Would you care to introduce him to others as a close friend of yours? These errors are easy for you to see. Perhaps, however, you make other mistakes which offend other persons as much as these would offend you. How do you know that you do not mispronounce certain words; are you always sure that the things you say and write are grammatically perfect? To you they may seem correct; but others may know they are wrong. Unfortunately people will not correct you when you make mistakes; all they do is to make a mental reservation about you. “He is ignorant and uncultured,” they think. So you really have no way of telling when your English offends others. FRE Sherwin Cody, perhaps the foremost teacher of English in the country, has prepared a simple 15-minute English test which you can take in your own home. This test, with the answers which will also be sent, tells you at once just where you stand. You can discover at a glance whether you make even slight errors. Give your- self this test. If you are efficient in English, it will give you greater confidence; if you are de- ficient, you surely want to know it, so that you can correct your mistakes. Book on English and 15-Minute Test Mr. Cody’s remarkable new invention, the 100% Self-Correcting Method, has already improved the English of more than 41,000 people. No useless rules, no tedious copying, no hard study. Only 15 minutes a day required. You learn by creat- ing the HABIT of using correct English. Noth- ing like Mr. Cody’s method has ever been used before! You do not want others to judge you unfairly. Write today for this test—it is free. We will also gladly mail you our new free book, ‘‘How to Speak and Write Masterly English.’”’ Merely mail the coupon or a postal card. Sherwin Cody School of English 1810 Searle Building Rochester, N. Y, Sherwin Cody School of English 1810 Searle Building, Rochester, N. Y. Please send me your Free Book, ‘‘How to Speak and Write Masterly English,’”’ and also Mr. Cody's 15-minute Test of my English. RII iss wee Siw Sw arg |e Satara. Siw ere ace etareces ee eee PON ice Sok o:n-wis n't ie 00k wae wine ee

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| PATENT TRADE-MARKS DESIGNS FOREIGN PATENTS MUNN @& CO. PATENT ATTORNEYS Associated since 1846 with the Scientific American 683 WOOLWORTH BUILDING 522 SCIENTIFIC AMERICAN BLDG. New York City Washington, D. C. . 411 TOWER BUILDING 364 HOBART BUILDING . Chicago, Ili. San Francisco, Cal. : ‘ 219 VAN NUYS BUILDING Los Angeles, Cal. He ete Books and Information on Patents and Trade Marks By Request. ; Associates in All Foreign Countries. To the Man With an Idea I offer a most comprehensive, ex- perienced, efficient service for his prompt, legal protection and the development of his proposition. Send sketch, or model and description, for advice as to cost, search through prior United States patents, etc. Pre- liminary advice gladly furnished with- out charge. My experience and familiarity with various arts, frequently enable me to accurately advise clients as to prob- able patentability before they go to any expense. Booklet of valuable information and form for properly disclosing your idea, free on request. Write today. RICHARD B. OWEN Patent Lawyer 6 Owen Building, Washington,D.C. 41-D, Park Row New York City DON'T LOSE YOUR RIGHTS f TO PATENT PROTECTION Before disclosing your invention to anyone send for blank form ‘‘EVIDENCE OF CON- jf CEPTION” to be signed and witnessed. A ff | sample form together with printed instructions [fj ; will show youjust how to work up yourevi- ff | dence and establish thesame before filing ap- ff plication for patent. As registered patent at- i) torneys we represent hundreds ofinventors all § over the United States and_Canadain thead- vancement of inventions. Ourscheduleoffees ff Ml willbe found reasonable. The form “Evidence ff | Mm of Conception,’ sample, instructions relating }} i to obtaining of patents and schedule of fees fj 4 sent upon request. Ask for them,—a postcard fj i will do. PATENTS AND 4. by 3 ie ee inate Registered Patent Attorneys in U. S. and Canada 274 Ouray Bidg. WASHINGTON, D. C. Originators of forms “Evidence of Conception.” NVENTORS your we YOUR IDEAS Send for our Guide Book, HOW TO GET A PATENT, and Evidence of Invention Blank, sent Free on request. Tells our terms, methods, etc. Send model or sketch and description Ee a a tion and Instructions Free. a Terms Reasonable. Best Ref- SMR Soha Sc neh awn sGekece ese kipe ene erences. | | STRERT 0c cccvcccccncccesccccecccrssccsese RANDOLPH & CO. | Dept. 130, Washington, pc. | SEW as oiled wine e oie sieeve TAME 6 n4sise seen e'e I Snares for Inventors (Continued from page 20) | turer but. one paid royalties to Selde, | Henry Ford was not granted a licens. and when he began shipping machineg in 1903, he went ahead without Paying royalties. Selden sued, and the first court decision sustained the patent. On an appeal, the decision held that the principal claim Wag limited to a two-cycle gasoline engine, The four-cycle engine had not been jy general commercial use when the patent was applied for. Ford and most of the other manufacturers had used a foy. cycle engine from the beginning, and the Federal courts decided that the Selde, patent didn’t cover that in the combing. tion. Half a million dollars was spent jn this litigation. The Selden patent was based on what are known as “combination claims,” jp which the invention consists of a new way of combining elements that already are known, to produce a new result. Most patents are issued on combination claims, because it is only rarely that anybody dis. covers something absolutely new. Anda patent based on combination claims is no | protection to the inventor if the device| can be made to work by omitting any single element of the combination. N INVENTOR got a patent on a de vice to use in coal stoves to enable them to burn kerosene as fuel. It waga new idea and should have made him a for tune. Unfortunately, in drawing up the claims he had included in all of thema groove to catch any dripping of oil. As soon as the device was on the market and making money, a clever young man bought one, filled up the groove and found it would work just as well. Then he dv plicated the device, all but the groove, and the courts held that the inventor had no redress. He had claimed more than he needed. ‘“‘However, most of the pitfalls that con front the inventor are of his own digging,” said one of the foremost of American patent attorneys. ‘I am speaking nowd the amateur inventor, and nearly all ir ventors are amateurs. “The amateur is full of fear that some, body will steal his invention. He need have no such fear if he protects himself with documentary evidence of the dated the original conception of his invention and of each stage of its development. He should also have a reliable attorney search Patent Office records toesee if the) invention is really new. And, most im portant, he ought to make sure that there) is a possible market for the device. “That is the way the professional it ventor works. He usually discovers the demand and then sets to work to supply it. Nine times out of ten he sells his invention before he applies for his patent, letting the purchaser get the patent while he turns his mind to another problem. “The amateur nearly always demands# flat sum in cash—a million dollars is4 favorite amount to ask. The professional on the other hand, knows that an inver tion, no matter how useful, must b developed and commercialized and gel (Continued on page 161) ~ © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. erall: stipt put « or it “ey one, ket ~ inve! inve of 2 rebu final Now colla seve inve but so W way prop Evel nut trac! of tk “ R brin inve irres pan gené devi chea mad weal Yet the rack men stea who tele} you he ¢ hea croe 450 rifle mo} of ; 10,¢

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October, 19% a lors | to Selden, a license, achines in it Paying rt decision ppeal, the claim was ne engine, t been in the patent ost of the d a four. Z, and the the Selden > combina. aS spent in d on what laims,”’ in a new way ready are ult. Most ion claims, Ly body dis. ew. Anda -laims is no the device 1itting any tion. nt on ade ; to enable l. It wasa e him a for- ving up the of thema of oil. As the market young man e and found hen he du groove, and itor had no ore than he lls that con yn digging,” f American king now ol early all in that some . He need ects himself f the date di is invention evelopment. le attorney soesee if the d, most im re that there evice, | fessional it) iscovers the rk to supply he sells his’ r his patent, patent while - problem. rs demands@ dollars is @ professional at an invel- ul, must be ed and gel — ) a e 6. October, 1925 Snares for Inventors (Continued from page 160) erally sells on a royalty basis, with a stipulation that his invention must be put on the market within a specified time or it reverts to him. “Marketing an invention, even a good one, isn’t always easy. Usually the mar- ket exists in the industry to which the invention pertains, but not always. The inventor of a new kind of soft collar, made of a special weave, met nothing but rebufis from the collar industry. He finally interested some outside capital. Now the collar people all are making soft collars and already have had to pay several millions in royalties. “Eyery railroad man, almost, has an invention or two to improve railroading, put few ever are adopted, because .to do so would mean rebuilding an entire rail- way system. Costs entailed are out of proportion to the value of the invention. Even so simple a device as a self-locking nut for track bolts, which almost every trackwalker invents, would cost hundreds of thousands of dollars to adopt. “DEVOLUTIONARY, basic inventions are the hardest to sell, though they bring the best prices when sold. Let the inventor beware, however, of selling to an irresponsible or under-capitalized com- pany. The most profitable inventions generally are improvements on existing devices that make them either better or cheaper; and these inventions usually are made by men familiar with the needs and weak spots of the particular industry. Yet bright amateurs sometimes do find the things that professionals have been racking their brains over for years. Re- member that Fulton, the inventor of the steamboat, was an artist, as was Morse, who invented the telegraph; Bell, of telephone fame, was a school-teacher, and you have a vision of the possibilities.” Machine Works Rapidly Sx thousand reproductions of typed pages, printed pages, pen-and-ink drawings, or prints of woodcuts can be made in an hour, it is claimed, with a new duplicating machine called a ‘‘rotaprint,”’ invented in Germany. Steel engravings, also, can be reproduced, and the machine is adapted for architectural drawings and sheet music. Colors will reproduce one at a time. In the case of typed material, a stencil is made first, as for a mimeograph, and this sheet smeared with a chemical preparation is passed through a series of rollers, after which prints can be made. Experiments in Balloon A BALLOONIST recently experiment- ed to determine the distances at which he could hear various sounds. He could hear a man’s shout at 1600 feet; frogs’ croaking at 3000 feet; orchestra music at 4500 feet; church bells at 5000 feet; a Tifle report at 5900 feet; and the noise of a moving train at 8200 feet. The whistle of a locomotive was heard farthest at 10,000 feet. 161 Have You An Idea? Our Offer: oF YouR INVENTION YOUR FIRST STEP Before disclosing an invention the inventor should write for our blank form “RECORD OF INVENTION” This should be signed ~and ~ witnessed and returned to us together with model or sketch and description of the invention for INSPECTION and INSTRUCTIONS No Charge for the Above Information Our Four Books Mailed Free to Inventors Our Illustrated Guide Book HOW TO OBTAIN A PATENT Contains full instructions regarding U. S. Pat- ents. Our Methods, Terms, and 100 Mechanical Movements illustrated and described. OUR TRADE MARK BOOK Shows value and necessity of Trade Mark Protection. Information regarding Trade Marks and-unfair competition in trade. OUR FOREIGN BOOK We have Direct Agencies in Foreign Countries, and secure Foreign Patents in shortest time and at lowest cost. PROGRESS OF INVENTION Description of World’s Most Pressing Problems by Leading Scientists and Inventors IMPORTANT TO MAKE YOUR CASE SPECIAL AND AVOID DELAY YOU SHOULD HAVE YOUR CASE MADE SPECIAL IN OUR OFFICE to secure protection, save correspondence and obtain early filing date in Patent Office. To secure special preparation of your case send $25.00 on account with model, or sketch and description. All Communications and Data Strictly Confidential. Interference and Infringement Suits Prosecuted. Our Organization offers PERSONAL SER- VICE by Experienced Patent Solicitors and Draftsmen. We Regard a Satisfied Client as our best advertisement, and furnish anyone, upon request, lists of clients in any state for whom we have secured patents. Highest References—Prompt A ttention—Reasonable Terms WRITE TODAY F VICTOR J. EVANS & CO. ree Patent Attorneys New York Offices Philadelphia Offices Pittsburgh Offices Cou on 1007 Woolworth Bldg. 714-715 Liberty Bldg. 514 Empire Bldg. p Chicago Offices,-1114 Tacoma Bldg. San Francisco Offices, Hobart Bldg. Main Offices: 760 Ninth Street, Washington, D. C. Gentlemen: Please send me FREE OF CHARGE your books as described above. @® This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6.

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Bh rt ira abe ‘ciara Ags thelial Min olen acon POPULAR SCIENCE MONTHLY fo mimes for Readers iim Ss : Quick Action Advertisin ADDING MACHINES FREE trial, marvelous new adding machine. Adds, subtracts, multiplies, divides automatically. Work equals $350.00 machine. Price only $15.00 Speedy, durable, handsome. Five-year guarantee. Used by largest corporations. Write today for catalog and free trial offer. Lightning Calculator Co., Dept. O, Grand Rapids, Michigan. ADVERTISING SERVICES ADVERTISE in 24 metropolitan dailies, 24 words, $15.00. Helpful Guide listing 1000 publications, 4c stamps. Wade Company, Baltimore Bldg., Chicago. 24 WORD ‘ad 355 rural weeklies, $14.20. Ad-Meyer, 4112P Hartford, St. Louis. CIRCULARIZE guaranteed lists. $5.00, 1,000. Pennell, Covington, Ky. COMBINATION Winner. 125 Magazines, 10c werd, rte inch, Thrice, Interstate Advertiser, Munsing, ch. ADVERTISING in all- magazines and newspapers at publishers’ lowest rates. Rate book free. Taylor's Advertising Service, Dept. 5, Freeport, Ml. INCH display, 88 magazines $2.00, thrice $5.40. Smith's Service, Wenatchee, Wesh. STRONG copy based on sound plans. Outline your roject for free analysis and plan. S. Wycross Co., nsdowne, Penna. AUTHORS AND MANUSCRIPTS PHOTOPLAY—Story Ideas wanted. $25-$500 paid. Experience unnecessary; outline Free to anyone. Write ‘oducers League, 312 St. Louis. WRITERS—Stories, poems, plays, etc., are wanted for publication. Literary Bureau, 117, Hannibal, Missouri. $$$ FOR ideas. Photoplay plots accepted any form, revised, criticized, copyrighted, marketed. Advice free. Universal Scenario Corporation, 214 Security Bldg., Santa Monica and Western Avenue, Hollywood, California. I WANT song poems. Casper Nathan, J-3544 No. Racine, Chicago, SONG Poem Writers’ send for proposition. Ray Hibbeler, D10, 4040 Dickens Av., Chicago. SHORT Stories, Articles, etc., typewritten and market- ed. Hursh Service, Dept. 3, Box 1013, Harrisburg, Penna. SONGS and song poems wanted. Radio Publicity Bureau, Box 24, Times Square Station, New York. AUTOMOBILES AND ACCESSORIES DELIVERY bodies for Ford Model T Chassis with inclosed cab, suitable for Contractors, Grocerymen and Farmers. Three styles. Price $37.50. Write Daniel Zimmerman, Craigville, Indiana. Agents’ names OLD spark plugs rebuilt. Guaranteed same as new. Standard makes. 30c each. We also buy old worn-out = For particulars write. B. S. Salvage Co., 46 West Kinney St., Newark, N. J. AUTO Body Polish, make your own, gallon costs less than pint bottle, formula $1. bill; Kemo Sales Co., 1452 East 118 St., Cleveland, Ohio. AVIATION The American School of Aviation announces a new correspondence course in mechanics of aviation. A thorough training in practical aeronautics. American School of Aviation, Dept. 6741, 3601 Michigan Ave., Chicago, Illinois. BOYS fly this three-foot model aeroplane. Small cost. Write for circulars. Aero Shop, 3050 Hurlbut Ave., Detroit, Mich. LEARN Flying Right. America’s Largest Strictly Commercial Organization. High class individual in- struction without restrictions. Write for further particu- lars. Johnsons’ Flying Service, Inc., Dayton, Ohio. DO you want a position where you can pay your way while learning to qualify as airplane mechanic or pilot? Send $2.00 for one yearly subscription to Slipstream Monthly—The Flyers’ Magazine and our employment service will help you get located. Only subscribers need apply. Slipstream Publishing Co., Dayton, Ohio. BLUEPRINTS TO the man who has a Home Workshop and likes to work with tools, Popular Science Monthly offers the opportunity to purchase blueprints giving details of the construction of useful articles for the home. The follow- ing are a few of the blueprints available: No. 1, Sewing Table, No. 5, Kitchen Cabinet, No. 13, Tea Wagon, No. 15, Workshop Bench, No. 17, Cedar and Mahogany Chest, No. 41, One Tube Radio Set, No. 42, Radio Receiver with three stages of amplification, No. 43, Four Tube Radio Receiver. Send 25c for each blueprint that you wish to a al Science Monthly, 242 Fourth Avenue, New York, BOATS AND LAUNCHES BOATS that always go are propelled by Ford engines. Ford dope free to boat owners. Harry Rider, East Nor- walk, Conn. BOAT-BUILDING Plans for amateurs. Rowing, sailing, speed, cruising. Free catalog. The Rudder, 9 Murray Street, New York. BRANCH OFFICE SERVICE WASHINGTON mail address $5 month. Established 1920. Address ‘‘Service’’, 605 District National Bank Building, Washinyton, D. C. MR. ADVERTISER: Ask today ‘or a copy of the “Quick-Action Advertising Rate Folder.’’ It contains some really important facts which will prove interesting and valuable to you. It also tells ‘‘How You Can Use Popular Science Monthly Profitably.”” You'd like to know, wouldn’t you? Address your inquiry to: Manager, Classified Advertising, Popular Science Monthly, 250 Fourth Ave., New York. Rate 30 Cents a Word. A10% discount is allowed on all contracts for six consecutive insertions. Advertisements intended for the Dec. issue should be received by Oct. 5th Prize Winners in Last Month’s Contest 7 first prize of $10.00 goes to Cecil H. Brown of Los Angeles, California, for his letter on Haywood’s advertisement. is Mr. Brown’s letter: Dear Sir: After carefully reading all the advertise- ments under ‘‘Money Making Opportuni- ties,” Haywood’s ad with reference to operating a tire shop interested me most, as I have a friend who is just starting a small auto repair shop and wishes to learn tire re- pairing as a side line in connection with his auto repair shop. I gave him Haywood’s ad and he is going to write them. Respectfully yours, Cecil H. Brown. Mr. John P. O’Connor, New Haven, Con- necticut, wins the second prize for the follow- ing letter on the advertisement of C. C. Collette Manufacturing Company. Here Dear Sir: The advertisement that interested me most was that of the C. C. Collette Mfg. Co., Amsterdam, New York, who employ agents to sell their product. This ‘‘Money Making Opportunity Adver- tisement’’ has enabled me to connect witha concern manufacturing a “‘live wire”’ seller. I have now found that the advertising columns of PopuLAR SCIENCE MONTHLY sure are full of ‘‘live wire’’ advertisements from “live wire’’ concerns. Respectfully submitted, John P. O’Connor. The third prize goes to Mr. G. D. Rey- nolds of Altoona, Pa., for his letter regarding the Auto Accessories advertisements. This is the letter: Dear Sir: I am a direct-to-consumer salesman of household specialties. I drive my own car; needless to say I drive it long and hard. Con- sequently I was interested in the Vapor Humidifier advertised by Critchlow. Its use has considerably lowered my selling ex- pense with a commensurate increase in profits. And it sells itself to fellow salesmen. I’m not much of a judge of mechanical con- trivances—but my motor ts! Yours truly, G. D. Reynolds. The winners of the other seven prizes and the names of the advertisers they wrote about are: George F. Aiken, East Providence, R. I. (Universal Scenario Corporation) Mrs. A. Graham, Independence, Iowa (American Photography) Mr. A. Letcher, Tucumcari, N. Mexico (E. E. Palmer) Robert H. Harper, Butler, Missouri (W. Hillyer Ragsdale Specialty Candy Factories) Glen W. Naves, (Scouting Equipment) Miss Louise Kenyou, Westerly, R. I. (Theander Novelty Company) Adele M. Clardy, Lavoye, Wyoming (American Photography Camera House) Announcement You will find on Page 4 of this month’s issue a NEW prize contest offering $100 in Cash Prizes for the best letters on the advertisements in the Money Making Opportunities Section. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. BUSINESS OPPORTUNITIES WE start you in business, furnishing e and women, $80.00 to $100.00 weekly Opera eee Pa System Specialty Candy Factories” anywhere er tunity lifetime; booklet free. W. Hillyer agate Drawer 19, East Orange, N. J. GOLD, Silver, and colored Sign Letters for win automobiles, trucks. Make them yourself with gee ae = ——— Fast sellers, Bie rot No experience. Stamp brings actual sam 1144 Pleasant Street, Oak Park, Illinois. a ering GET into line with Gilbert’s House Wiveg’ neces good profits, easy sellers, Six Samples $1.00, Gna Co. Box 26-K, Milford, Conn. $1.00. Gilbert FREE Book. Start little mail order busines, pp 976 Cortlandt Street, N. Y. 7 Pie LEARN the collection business. Good income: qa results. , interesting booklet, “Skillful Collecting "ht ational Collector’s Association, Science Bi 4 ark, Ohio. ullding, Ney BECOME a Foot Correctionist. A New Pron not medical nor chiropody. All the trade you ana to; many are making $3000 to $10,000 yearly, easy temy for training by mail, no further capital needed or buy, no agency or soliciting. Address Stephenson tory, 10 Back Bay, Boston, Mass. MIRRORS re-silvered at home. Costs less than bem, per square foot; you charge 75 cents. Immense prot, plating auto parts, reflectors, tableware, stoves, Refinig, ing metal ware, etc. Outfits furnished. Write for ing. mation. Sprinkle, Plater 94. Marion, Indiana, MR. ADVERTISER: Ask today for a copyg “Quick-Action Advertising Rate Folder.” It contalyy some really important facts which will prove interestig, and valuable to you. It also tells ‘‘How You Can tg Popular Science Monthly Profitably.”. You'd like to knoy, wouldn’t you? Manager, Classified Advertising, Populz Science Montnly, 250 Fourth Avenue, New York “SUCCESSFUL!!! Mail Order Business}! 25c! Surety Service, 551 Harvard St., Rochester, N. tener dies "Tae Ge in Bea fac na nite ates. 20pular Science Monthly, Ave., New York. y, rm SOMETHING new in the Mail Order Busing Starts you in business right at home. No part time, @ house to house methods. Station A, Box No, 6, im Diego, California. H.N. Allison. INCH Display Advertisement, 166 M a year, $50.00. _Woods Popular Service, Atlantic City, PATENTS procured; Trade Marks Registered—| comprehensive, experienced, prompt service for the pr tection and development of your ideas. Pre advice gladly furnished without charge. Booklet of ph weg Rage a idea free on nee icharc . Owen, wen Bldg., Washi ‘ or 41-Z Park Row, New York. nn MAKE big income operating a collection , No capital necessary. We teach you fully. Write tion Instruction Institute, 313 Waverly, Syracuse, N.Y STOP plodding! Be successful. Operate a tire rep shop. Make big profits in any locality. We teach youm furnish complete equipments, $100 up. Book of tunity free. Chicago. Haywood's, 1306 South Oakley Aven START small home Mail Order Business, Books 2c. Harvey Teeple, Decatur, Indiana. START for yourself. Be independent. We show yw how. The mail order way. Send $1.00 for instruction Dp. 131. E. Noon, Windsor, Va. $50 A week evenings. Mail Order Business. Boon tells how. Sample and plan 25c. Free—9 artids worth $3. P. Bradford Co., Shawnee, Okla. WHY work for others? Mirror Resilvering Simplife, Book of instructions 25c prepaid. C. W. Steene, Mim and Glass, 230 East Water St., Syracuse, N. Y. FREE Booklet describes 52 plans tor making $2# to $100.00 weekly in home or office business of your m. Downs Co., 2328 Myrtle, St. Paul, Minn. MANUFACTURE Dry Chemical Fire Ext big profits, demonstration makes sure sales. $1.00. OGA. Co., 3 Ocean Way, Long Beach, Cal. PATENTS commercialized, D. C. S. Auto Produ Co., Indianapolis, Indiana. ; DON’T buy a business. Start one yourself. Sm ge Information Paul Kaye, 149 Broadway, N.1, ept. R. THE Great Wheat Secret. New book showing the cam of wheat swings and how to forecast them. U method for traders, speculators, millers. E; folder free; write today. Market Forecaster Co., Dm B., Box 174, Topeka, Kansas. LEARN Furcraft—RBig Profits waiting in every a munity. Easily learned at home in your spare time. G into a high-grade business for yourself. Uncrowded No peddling or soliciting. We teach you how. Be Write today for free book and full particulars. Ene 5c stamps, mailing cost. No obligation. Northwe Fur Co., Suite 9787, Sunderland Building, Omaha, BUSINESS Guide with free legal service sells evel where. Wells cleared $1,185 in 35 days. Write for outfit. Nichols Co., Naperville, Ill., Dept. 1B. IF you really want to make money, get my propos right NOW. Russell Johnson, Clarkfield, Minn. $100 WEEKLY, income starts immediately, ic free. Dr. Abell, 141 The Arcade, Cleveland, Ohio. BATTERY shop equipment and supplies at sale. Adams-Barrs, Columbus, Ohio. ie OPPORTUNITY seekers—$200 monthly in 8 u business. 52 plans free. Busy Bee, 154 East 170th8 New York. MR. ADVERTISER: Ask today for a copy “Quick-Action Advertising Rate Folder.’’ It com some really important facts which will prove intere and valuable to you. It also tells ‘‘How You Can b Popular Science Monthly Profitably.’’ You'd like know, wouldn’t you? Address your inquiry to: nae Classified Advertising, Popular Science Monthly, Fourth Ave., New York.

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for & copy ot der.” x i prove interestig Susiness!! -, Rochester, N.Y ee ery fi mnihly, 200 Feo a, 1 Order Busine NO part time « \, Box No. fit ene 166 M e, Atlantie Cine rks Registered—j service for the pr. deas, ea free on Washington, De collection , ully. Write ly, Syracuse, N.Y perate a tire reper . We teach youm p. Book of th Oakley Aven SS Business, Books , ent. We show ya 00 for instruction Silvering Simpliie, WwW . Steene, Mim use, N. Y, for making $208 usiness of your om inn. Fire D re sales. Fo g Beach, Cal. S. Auto Produdl 1e yourself, Smal ) Broadway, N. !, 1k showing the cam them. Unequal! llers. Eye-opedi recaster Co., Det iting in every yur spare. time. G f. Uncrowded fd you how. Be articulars. E ion. Northwe ding, Omaha, service sells evel ays. Write Dept. 1B. get my prope leld, Minn. ediately, pa veland, Ohio. supplies at a ynthly in 8 ip 154 East 170th ' for a copy 4 ; pial ia prove inte ‘How You Call af vom iquiry_ to: r ence Monthly, ze 6. He Poked His Fingers in a Lion’s Mouth (Continued from page 35) was far harder. The beast weighed 1/4 tons and had such big feet and was built go close to the ground that it was hard to cast it. Ten men hobbled Mr. Rhino, tugged and tugged, and couldn’t budge him. Finally, some one got the brilliant idea of building a hill with bags of grass and slowly heaving him over on it. Some job! But it was done, and after two operations the animal was able to see again. ; ; Camels are a little easier to throw. This is necessary when something hap- pens to their feet, as often does. Mes? of the troubles Doctor Blair has to contend with are digestive. Lions, camels, monkeys, bears, antelopes, pirds, snakes, all suffer from digestive troubles. Castor oil and cod liver oil, of which the Zoo uses gallons and gallons, are in constant use. And it cures most of the digestive ills. But it doesn’t cure the snakes. Snakes, when they are ill, refuse to feed and have to be artificially stuffed, which is quite a job. One snake, whose stomach was 51% feet from its mouth, had to have rabbits, guinea-pigs, and chickens stuffed down his throat once every four weeks for a year. Pneumonia gives the Zoo doctors much concern. Monkeys particularly suffer from pneumonia, for they are extremely sensitive to change in climate. Bronchi- tis, mumps, and other familiar diseases are common troubles with monkeys. And yet these all respond to treatment. Fresh air and inhalations of medicated vapors bring a ready cure. As a matter of fact, much of Doctor Blair’s work is preventive medicine. Anything that is likely to cause trouble is carefully avoided. Diets constantly are being experimented with. All the ani- mals are studied and watched carefully. Constant study has been absolutely necessary, for when Doctor Blair came to the Bronx Zoo, he had to form his own department. He was called there from McGill University in Toronto, where he was a student of the class of 1902 in com- parative and veterinary medicine, to organize and develop the New York Zoological Society’s medical department. That was 24 years ago. OCTOR BLAIR’S staff is small, but so well trained that every morning he gets reports that tell him the exact con- dition of every animalinthe park. The three curators of the Zoo—Dr. William T. Hornaday, who designed the park, opened it November 9, 1899, and has been its only director, in charge of 565 mammals; Dr. Lee §. Crandall, in charge of 2474 birds; and Dr. R. L. Ditmars, in charge of 550 reptiles—report every symptom to the Medical Department. Doctor Blair immediately investigates all cases that seem to require his atten- tion. If necessary, the sick animal is re- moved to the hospital, the best equipped of its kind, with a surgical ward, a medical ward, an operating room, a hoofed-animal ward, a diet kitchen, and a morgue, all conveniently arranged. From $ Clerk — to $852° Radio Expert How a young man discovered his opportunity in a fascinating new field, and quickly prepared himself in his spare time for the position he wanted. As related by himself. ig WAS interested in radio from the very beginning. I bought a little one-tube set when radio first. be- came popular and I experimented with it, bringing in snatches of song from the air and trying to get distant stations. But my set was very much of a mystery to me. Like most people, I knew how to use it, how to tune in on local stations, but I did not under- stand how it worked. I often wondered. ‘‘At that time I was working as | a clerk in a large mail order house. I took the position because I thought it would be a stepping-stone and that I would quickly advance to something bigger. But years went. by and I was still a clerk. Somehow I had fallen into a rut, and there I remained. I used to get terribly dis- couraged at times, and I wondered what my future would be. Would I never be anything more than just a clerk? “T drifted on, and nothing ever hap- pened. I got an occasional increase in salary, but that was all. I was becom- ing resigned, was losing whatever shred of ambition I had left. My salary reached $22.00 a week, and there it remained. I knew I could never earn more in that kind of work. But what could I do? For what was I suited? A New Industry “‘Then came the big radio boom, and everybody began talking about the wonder- ful new industry. Half the people in our town bought receiving sets. On the trains I heard nothing but radio gossip, and the newspapers were crowded with news on radio development. I had a sudden idea— an inspiration. ‘“‘Here was an industry that was still an infant compared to other industries. It was young and fast-growing, and evi- dently would some day be one of the great- est industries in the world. Surely in so new and important an industry there must be big opportunities for beginners—a rare chance for quick success and rich rewards. I would get into the field at once, start at the bottom and grow up with it! ‘I would get out of the rut into which I had fallen, into a new field ripe with opportunities. “But how? I had to depend too much upon my $22.00 a week to give it up. If only I could study radio at home in my spare time, and prepare myself for a radio job without giving up my regular work. I decided to make inquiries, and discovered that just such a course was offered by the National Radio Institute of Washington, D. C. I enrolled for their famous correspondence course, keeping it a secret from everyone at home. ‘“‘For several months I studied at home, in the evenings and whenever I could spare a half-hour or so. The time passed quickly because it was so fascinating. In a few months I had mastered what I had _ be- lieved ‘the mysteries’ of radio, and was qualified to take a position in charge of a radio department in a large wholesale house. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See “How surprised everyone was when I announced calmly: —and I'll admit a little proudly!—that I had _ graduated from the National Radio Institute and that I had my certificate as a radio- trician. They were even more surprised when I told them that the Institute had found a position for me right in my own town at $50.00 a week! They all wanted to know how I did it—and some of the fellows were mighty jealous. I Earn Big Money ‘‘Advancement came quickly, and now I am a radio engineer earning.$85.00 a week. Very often I earn extra money in my spare time helping people-put up their sets. 1 ex- pect another promotion soon and it will not be long before I am earning $100.00 a week. Radio is constantly progressing, there are new improvements all the time, and those who are in the field naturally develop as radio develops. I am glad I got in early. ‘‘T am glad to write this story for publica- tion because the National Radio Institute alone has made my success possible. It offers an absolutely complete course which qualifies you for the Government first-class license and for the big-pay jobs in radio. I would advise anyone who is interested in radio as a profession to use this coupon and send at once for the valuable information that is offered free. Don’t hesitate to use it—there is no obligation. I, too, sent off for the free information before enrolling. Why don’t you do it—now? Special Offer ‘‘A special reduced rate is being offered to those who mail the coupon AT ONCE. Get in on the ground floor and save money. Just address the National Radio Institute, Dept. 12 MB, Washington, D. C.” National Radio Institute Dept. 12 MB, Washington, D. C. I am. interested in radio as a profession. You may send me, free and without obligation, your interesting little book, ‘‘Rich Rewards in Radio,"’ telling about the future of radio, and all information about your spare- time, home-study plan and your free employment service. Ra res Co cbecnvcenetteanane . Age . Address - - - .- a = er nigjdi phim pabérien diene DNatarccevcvewe

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Sees ary San eargey tll a inl 2 eminem a aan Ne oi ib A beepegp etek te eh cee an aemntenanmemarei steams #8 2s iv 5 a % pam eee Sp OR Aaieliow males tliat ceased lpn Met eee pe rome to gery tin ph edna ae oe noe October, r gation invited. if WANTED Men to manufacture Metal Toys and Novelties. Good ' chance to start your own well-paying business producing such big sellers as Toys, Novelties, Ash Trays, Book-blocks, Souvenirs, Advertising Specialties, Paper Weights, etc. We furnish forms with complete outfit for speedy production. Absolutely no experience or tools necessary; no special place needed. Small investment puts you on road to suc- cess. Demiand exceeds supply and we assist and co-operate with our manufacturers in selling their products. We put you in touch with the buyers and assure an outlet for your goods. Strictly a business proposition and thorough investi- splendid opportunity for an enormous and profitable business for ambitious men, apply. Catalog and information mailed on request. Metal Cast Products Co., 1696 Boston Road, New York No others need sie = New Kind of Belt Reduces Waist— Easily! Look slim at once Say ““good-by’’ to bulging waist- line. Amazing new belt liter- ally melts fat away. Produces same result as expert mas- seur. Off with that bulging waist- line. Melt fat away. At last you can do it safely, easily, com- fortably—and without great ex. pense. Not by starvation diets or harmful drugs. There is only one correct way to take fat away—that is A Self-Massaging Belt That Is Always on the Job Massage—Science proves —is the only safe, correct way of removing weight. But Masseurs charge big fees— they are effective only fora half hour or so occasionally. The remarkable Weil Reduc- ing Belt is always on the job. Every second you wear it, it works for you. Massaging fat away with every move you make, 4 to 6 inches reduction in a few weeks is quite usual. As it reduces fat, it builds up healthy, firm muscles. It sup- ports the stomach walls, im- proving digeston, gives better carriage. You feel years younger. The Weil Health Belt is |/7 made of the same kind of }/// scientifically treated rubber > that is used by professional athletes and jockeys. Endorsed by physicians. Write for description and special 10-Day trial offer. The Weil Co., 1010 Hill St., New Haven, Conn. "| Sippehamtaeneseaemaded cl cd car cl ae ae ae ee a es I The Weil Company, 1010 Hill St., i New Haven, Conn. Gentlemen: Please send me, without obligation, 1 complete description of the Weil Scientific Reducing } Belt and also your Special 10-Day Trial Offer. ! N ” Vics anna Db wbhenubebaaceeewesek a aioli di oeintbin ge iss aienidm ie ecimmimmsaaaelie f ciey 0 ee a = ea aa | COMMERCIAL ART Meyer Both Company, maintaining the most widely known Commercial Art Studios in the World, offers you a practical training based upon 25 years’ success in producin: over a quarter million commercial drawings for leading advertisers. Many of the full page illustrations appear- ing in leading national magazines are drawn by Meyer Both Trained Artists. Our graduates are filling attractive positions in every section of the country. Home study instruction. GET FACTS BEFORE YOU ENROLL IN ANY SCHOOL Ask the advertising manager of the leading newspaper in your locality about us. Send 4c in stamps for illustrated book telling of the success of our students, and the unusual opportu- nity for both men and women in this attractive profession. MEYER BOTH COMPANY Dept.35 Michigan Ave. at 20th St. CHICAGO, ILL. NOTE—To Art and Engrav- ing Firms: Secure prac- tical artists among our graduates. rite us. yy Rann HEHE f Qi ull Travel—See Your Country Common Education Sufficient $158 to $225 a Month ALL POSTAL SALARIES JUST RAISED MAIL COUPON IMMEDIATELY a Franklin Institute, Dept. G-278, Rochester, N. Y. Sirs: Send me without charge, (1) sample Railway Postal Clerk Examination questions; (4) tell me how to get a U. S. Government job; (3) send fi Steady Work—No Layoffs—Paid Vacations a which examinations will be held and free sample coaching. I | Name Many Other U. S. Gov’t Jebs Now Obtainable J Address (® > This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. st of places at Tete eee eee eee eee eee eee eee eee eee eee) How to Pick a New Bogs | (Continued from page 32) whom he can turn for such infor source of information about a job y, remarkably demonstrated recently by , successful advertising manager who drafted for an important executive Dos. tion with a publishing house. At eight o’clock in the morning a total str telephoned to his home, with the Tequest that he meet the stranger in his Office a 10, to discuss a possible connection, Immediately the advertising man called up a number of his friends, asking fact about the concern and its owner. Ty hours later he went to keep the appoint. ment, having clearly in mind the pag history and policy of the Publishing house, as well as the record and reputation of the man he was to meet. As a result he was able to make a prompt decision, with a clear understanding of the cop. ditions he would meet in making the change. OF COURSE, most of us are not g fortunate in tapping reliable source of information, yet often we fail to get the facts simply because we fail to try. The use of scientific methods is not the gole privilege of employers. More and more men who are seeking to better themselves are applying some of the same methods, Instead of doing all the answering of application queries, they are learning to put some pointed queries themselves, They are putting the boss on the carpet. They are picking studiously and carefully the man and the firm to which they may give the best possible service and asa result have the greatest chances for success. Recent Publications Biology, by Vernon Kellogg. How to study biology for yourself, with a list of some of the best books about it. American Library Association. Man’s Life On Earth, by Samud Christian Schmucker. A vivid, interest- ing story about what is known today concerning men who lived before recorded The Maemillan history. Illustrated. Company. The Wonder Book of Plant Life, by J. H. Fabre, translated by Bernard Miall. A skilled observer of nature shares his knowledge of the marvels of plant J. B. Lippincott growth. Illustrated. Company. Plants and Man, by F. Bower. In teresting essays on every-day botany. Illustrated. The Macmillan Company. High Lights of Geography —North America, by David Starr Jordan and Katherine Dunlap Cather. A new kind of geographical reader for children that gives fascinating legends and stories of geology not found in the ordinary text book. Illustrated. World Book Company. Automobile Starting, Lighting, and Ip nition Systems, by Victor W. Page. comprehensive explanation of electrical systems for motorists, students, me chanics, and repair men. Revised. Com tains 325 wiring diagrams. Illustrated. Norman, W. Henley Publishing Company. : Mati The value of tapping every availab is (442-029 i -.lt( ce «fs en ge eee 6 eet eee ff O08 eee

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Information TY availabl, t a job W. cently by a yer who CCUtIVE pox & rom on / Man called asking fact, wher. Ty the appoint. nd the past _ Publishing d reputation As a result ipt decision, of the Con making the are not 9 Able sources Lil to get the 0 try. The 10t the sole e and more themselves 1e methods, iswering of learning to themselves, the carpet, 1d carefully 1 they may e and asa hances for ions - How to h a list of American y Samud 1, interest wn today e recorded Macmillan e, by J. H. Miall. A hares his of _ plant Lippincott wer. In- - botany. mpany. y — North rdan and new kind dren that stories of ary text Jompany. , and 2 Page. electrical nts, me ed. Con lustrated. Yompany. ee | at your finger ends Know the facts in Electricity. They mean_more money and better position for you. Hawkins Guides tell you all you need to know about Electricity. Every important electrical subject covered so you can understand it. Easy to study and apply. A com- plete, practical working course, in 10 volumes. are pocket size; flexible covers. Order a set to-day to look over. HAWKINS GUIDES 3500 PAGES 1 A VOLUME 4700 PICTURES 1 A MONTH These books tell you all about — Magnetism — Induction — Experiments — Dynamos — Electric Machinery — Motors — Armatures — Armature Windings — Installing of Dynamos— Electrical Instru- ment Testing—Practical Management of Dynamos and Motors -Vistribution Systems-Wiring-Wiring Diagrams —Sign Flashers—Storage Batteries—Principles of Alter- nating Currents and Alternators—Alternating Current Motors—Transformers—Converters— Rectifiers—Alter- nating Current Systems—Circuit Breakers—Measuring Instruments—Switch Boards—Wiring—Power Stations —Installing —Telephone —Telegraph —Wireless—Bells— Lighting—Railways. Also many Modern Practical Appli- cations of Electricity and Ready Reference Index. SHIPPED TO YOU FREE Notacent to pay until you see the books. Noobligation tobuy unless you aresatistied. Send Coupon now—toda —and get this great help library and seeif it is not wort $100 to you—pay $1.00 a month forten monthsor returnit. THEO, AUDEL & CO. 6S W. 23rd St., N.Y. Please submit for examination Hawkins Electrical Guides (Price $1 each). Ship at once, pre- paid, the 10 numbers. If satisfactory, I agree to send you $1 within seven days and to further mail you $1 each month until paid. Signatur Occupati Employed by Resid Refer: 10T-34 Auto Men vented am © jobs now open in Cali- forniaand everywhere , fortrained Auto mechanics, ignition and battery experts, . garage managers, etc. We will train SS j you, quickly and easily in our big Million “SWF Dollar School of Shops. No previous experience amfam, OF education needed. Expert instructors. ay Short, practical courses. Low tuition rates. wecn,) YOu can earn board and room expenses easy While learning. 15,000 successful graduates “\_ assure your success. Ww >. FREE AUTO BOOK Big illustrated book tells you about ("=a ; this famous school and how we 4 help you get big-pay jobs. y ial as ie Write—Depe. = Ut NATIONAL [Book Automotive & Electrical Schoo eles, California What Could You Do With $50—? See the Cash Prize Offer on Page 4. A SERVICE FOR YOU In Buying Radio & Tool Equipment For list of tested and ye products write ys Popular Science Institute of Standards. age 6. Los An Here Are Correct Answers to Questions on Page 57 1. It is due to colored pigments that are a part of the movable curtain in front of the eye, the curtain that regulates the amount of light that enters the eye. 2. The heat increases the vibration of the atoms, or perhaps of the electrons inside the atoms, so much that they finally begin to start waves in the ether. 3. The pane has two surfaces; its inside surface and its outside one. One of.the two images is reflected from the inner sur- face; the other image from the outer one. 4. If a deep bed of sand on the sea- shore or in a river bed is saturated com- pletely with water and especially if there is a spring of water seeping upward through it, the sand is apt to be loose, so that a person getting into it will sink. This is a quicksand, but it is a far less common thing in fact than it is in novels. 5. Remember that what happens when you charge the battery is that a chemical accumulates on one of the plates. If you tried to use an alternating current a little of this chemical would be formed first on one plate and then on the other. While one lot was forming the other lot would decompose. 6. No. The appearance of rays or beams of sunlight is caused by fine dust in the air, just as a ray of sunlight enter- ing a dark room will light up dust motes in the air so that you can see the path of the beam. 7. Space transmits the ether waves of radiant heat, it does not absorb them. Only things that absorb the rays are warmed by them. Our hand absorbs them and that is why sunshine feels warm to it. 8. They are clouds of gas, perhaps with some solid fragments, that come into the solar system from outer space. 9. Not any serious damage. If we hit the head of the comet and there happened to be some fairly large solid lumps in it there might be a little damage from falling stars. 10. This is a form of hypnotism, you yourself being both hypnotist and subject. Suppose you are climbing down a ladder out of a burning building. Your atten- tion is fixed completely on the fire and on the progress you are making in your escape. You have no brain power left to notice anything else at all. 11. It was cut down, during millions of years, by the Colorado River that still flows in the bottom of it. 12. Because the driftwood has taken up a lot of mineral elements from the sea water. When these mineral elements in the wood get into a fire they color it different colors, just as the salt colors it yellow or as red-fire composition would | color it red. : © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 6. With These Tools Many Earn °3500..x NoExtraCharge For This Outtit . ITH tools just like these many earn $2500 to $3500 a year—even more. All you lack is the training. That too I can give you, right in your own home. Keep on working at your job. Just give me a few of your spare hours. With my remarkable, practical method, I will soon make you a draftsman. Then you can take your place among the tensof thou- sands of well paid men who have found draftsmanship a sure road to success. Right now is the time to start. A tremen- dous era of prosperity is just ahead. Right now the papers are full of advertisements calling for skilled men. No chance for the man who wants to learn “on the job” — but more and more opportunity for the man who is trained. Mail Coupon for My Great Special Offer I am ready to do a great deal for ambitious men. Write me at once. Let’s a together on your future, You'll be surprised at the wonderfully liberal offer I will make you. , doesn't count. If you have vim, vigor and ambition I'll give you your chance to get ahead. Write me today. Put it up to me to show YOU how you can become a draftsman at big pay Chief Draftsman Dobe, piv. 13-67 1951 Lawrence Avenue Chicago, Hl. Chief Draftsman Dobe, 1951 Lawrence Ave. . Div. 13°67 Chicago, Il. Send me your Great Special Offer open ow to ambitious men. Also your book, ‘Su Draftsmanship.” No obligation on my part. Mone

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er 5 vo PERE tecnsta es cl ES Se Ri aw Are You Headed For the Junk Heap? You know how the aviator looks over his machine before taking off. You have seen the automobile racers tuning-up before the getaway. At every railroad station you have observed the engineer and fireman oiling up the locomotive and examining the bearings. In the power house and in the shops constant inspection and super- vision is given dynamos and everything that runs. Now how about the haman machine—how about you’? What attention have you paid to your body? Have you seen to it that every part, every organ, every muscle -- was’ kept fit and strong ready to function, either in performance or in ward- ing off illness and the in- roads of disease? Or have you, through ignorance, or laziness, or sheer neglect, permitted it to become rusty, faulty, weak, rheu- matic, catarrhal, tuber- cular, debilitated, despised —a wreck ready for the junk heap—a reject such as no one respects nor admires? Thousands Are Guilty of this crime against crea- tion—this offence to hu- manity. They know deep down in their hearts that they have .knowingly, wil- fully contributed to the wrecking of their bodies— and you may be numbered among them, perhaps a pitiful apology tor a man. Let’s Get Together But don’t stand by and see your body go on down to destruction and perdi- tion. Stop right where you are and get your bearings. Let’s get together—you and I—and see what we can save—see if we can’t put you on your feet again and make a 100 per cent. man out of you. I’ve done it with almost countless numbers—I can do it with you. Let’s look facts right in the face. You tell me your story—then I'll tell you how I can and will help you, I Can Help You as I have helped thousands of others in the same hopeless condition—the weak, the timid, with fits of the blues all day long and disturbing dreams at night. é J Why go on feeling miserable, out of joint with the world—ostracized by men, despised by women—when there’s a way out of it—a way to a newer, better life with abundant vigor, strength and happiness. I Want To Send You MY FREE BOOK “The Promotion and Conservation of Health, Strength and Mental Energy.’’ It will show you how to eliminate from your system, in a very short time, the distressing disorders which ve made you feel yourself a misfit in the scheme of humanity; how to build up your body, strengthen ALL your vital organs, turn your anaemic blood into a radiant red and feel the thrill of new life coursing through your veins. It will teach you how to become FIT physically and mentally; fit for busi- ness, for society, for the H home, a power among men, a pleasing personality to women. My pupils and graduates in all parts of the world will back up every word I say—you'll find photos and letters from some of them in the book. hat I es done for them I can do for YOU. I GUARANTEE SEND FOR THE BOOK NOW. IT’S FREE. Fill out the coupon and enclose a 10c piece (one dime) to help pay postage. Don’tdelay. SEND IT TODAY LIONEL STRONGFORT Physical and Health Specialist for Over 25 Years Dept. 37 Newark, N. J., U. S. A. Pest eee eee e888 Se eS ee eee FREE CONSULTATION MR. LIONEL STRONGFORT, Dept. 37, Newark, N. J. Please send me absolutely free enlightenment on the Promotion and Conservation of Health, Strength and Mental Energy. I enclose a ten cent piece (1 dime) to help cover postage and have marked (x) before the subjects in which Iam most interested. STRONGFORT The Perfect Man . i ' Hy F i é i 1 O Colds O Short Wind i] O Catarrh O Constipation } OG Asthma O Indigestion 2 O Hay Fever O Nervousness O Headache O Rheumatism t O Thinness O Weak Eyes ft a a oO hehe 2 re a umbago oO anhoo estore u O Flat Chest O Peor Circulation 1 OC Youthful Errors O Round Shoulders i OG Increased Height O Lung Troubles O Pimples O Muscular Development i O Insomnia O Great Strength t Mbox mente aenew nn cobas | meer mm Re me me em mee me ee ee ewe mew ewes eee ; ee IR eon nam nawinecacenceous ee ee ee ee | ERS ee State What Set Shall I Build? (Continued from page 59) advisable to remove a turn or two from coil C. This is necessary only if the condenser E, when the plates are fully disengaged, fails to stop the tube from oscillating or squealing. Other readers have inquired whether they could substitute condensers of a different capacity in the four-tube re- ceiver. This also can be done. In fact, changes of condenser capacity always are feasible if the coils that the condensers tune are wound with the proper number of turns of wire so that the broadcast band of wave lengths can be covered. Some radio fans have built the one-tube set with the idea in mind of later re- building the parts into the four-tube outfit. In such a case it would, of course, be advisable to purchase .0005-mfd. (23-plate) variable condensers. The four-tube receiver is reeommended particularly to the radio fan who wants the limit in distance-getting ability, combined with great selectivity and un- distorted volume. It is not a good set for the absolute novice to attempt, but if you already have built and operated at least one receiver, you should have no difficulty in successfully completing the POPULAR SCIENCE MONTHLY four-tube receiver. ERE is what one radio fan in Wash- ington, D. C., writes about this receiver: “TI constructed the four-tube set according to your specifications in the July number and am securing very fine results—just the results you promised—fine tone, volume, distance, and selectivity. “I had previously made another four- tube hook-up recommended by POPULAR SCIENCE MONTHLY, also with most grati- fying results.” There are several. reasons why this set is better than other four-tube circuits that operate on the same general principles. There are no moving coils to cause queer effects while you are trying properly to balance the receiver. Regeneration is obtained without changing the wave- length settings of either tuning dial. No audio-frequency current is permitted to flow through the plate coil, so that dis- tortion from this source is eliminated. And these advantages are gained without complicating the circuit or increasing the difficulty of construction for the home radio-set builder. In fact, this receiver is easier to build than any other set using the same number of tubes and capable of giving anywhere near the same results. The relation between sensitiveness and selectivity can be adjusted on either the one-tube receiver of Fig. 5 or the four-tube receiver of Fig. 3 by changing the number of turns in coil A. Turns added to coil A in either case will increase the sensi- tiveness and broaden out the tuning to some extent. This means that if you are located 50 or 100 miles from the nearest broadcasting station or, through force of circumstances, you find it necessary to use a short outdoor antenna or even an indoor antenna, the lack of sensitiveness can be made up in part by increasing the number of turns in coil A. BY DOING Every phase of all ranches > ELECTRICITY taught by Actual Practice In America’s foremost and oldest institution for trade training No Books Used Individual Instruction Start Any Day Write for FREE 64-page catalog THE NEW YORK ELECTRICAL SCHOOL 40 West 17th St., New York City ONLY $1. 00! deg an I aah oy ret ime watchs Sewsis, 8 Adjustments including heat, cold, iGoctrontama Boe ——" Ag enn Fp ky “et FREE Chain FREE 832! - ffer lasts. Get] of Advance Watch Beautiful otrie book in colors and ‘this amazing $1.00 down ote! FREE! . STUDEBAKER WATCH CO., Dept. W23 South Bend, Indiana Canadian Address: Windsor, Ontario es AUTO _a Real Protect yourself from toughs , and hold-up men. Most amaz- ing ti ® in. real atuomatic until you pul! R ‘rom ee il the Biase OP » Tel 5 eading Glass, Mir- ror, Sun Dial, Com- , » ete. Loads of ‘un; useful, instruc- tive. A real protecto. Pocket Mirror. Magnifying to’ ak. with Postman oO: matic SI 1.48 postage. 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Giving interesting information and vital facte—just what you want to know about advertising. Write today: PAGE-DAVIS SCHOOL OF ADVERTISING, Dept. 1367 3601 Michigan Ave., Chicago, U. S. Ay © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS See page 6. EE NS hE Pes

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How to Charge Batteries (Continued from page 62) trade names by the makers of storage B patteries. These devices do not ordi- narily employ a transformer. Conse- quently they are not capable of re- charging the usual 110-volt storage B pattery unless the battery is cut in two sections and the charging current sent through each section separately, or both sections are connected in parallel. The reason for this is simple. The line voltage in your house generally is not much more than 110 volts, while the voltage of the ordinary 110-volt lead or alkaline type battery runs up to nearly 120 volts when fully charged. Figure 4 shows the connections to two double-pole, double-throw switches. This arrangement permits you to disconnect the B battery from the receiver, connect it with the charger, and also put the two halves of the battery in parallel for charging. Disconnecting the battery from the receiver is necessary, because other- wise there is chance of a short circuit from the electric-light line by way of the ground wire of the receiver. HE use of the second switch to change the battery from series to parallel can be avoided, of course, by using flexible leads from the charger and simply clipping one to each half of the battery. It will not require twice as long to charge the whole B battery this way, since the full charging current will flow through each half while it is connected with the charger. You should use a hydrometer to de- termine the state of charge of the A bat- tery, but you will find after a few months that the simplest plan, after all, is to give the A battery a charge once a week just as you wind the clock every Sunday. The battery should not be left more than two or three weeks without a charge anyway, and the amount of current put into your battery by any of the modern chargers will not harm it, even if you do charge it afew hours more than necessary now and then. In fact, an occasional overcharge is actually good for the battery. Storage B batteries of the lead type should be recharged for about 12 hours once every two weeks to keep them in good condition. The fact that the voltage of the storage B battery still reads up to 96 volts does not mean that the battery is not in need of a charge. There is just one other vitally important point and that is: Be sure to keep the level of the solution in the battery above the tops of the plates at all times by the addition of distilled water whenever necessary.

STEALING radio programs may be the next crime. Invention of a way to fix sounds broadcast by radio on records was announced recently in Vienna, Austria. The broadcast sounds are re- corded on disks on a spiral consisting of a continuous line of points more or less strongly magnetized, according to the strength or quantity of sound. The records may be played later any number of times. The disks may be demagnet-

ized by a simple process and used again.

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Automobile Experts in Demand Study with the same school that helped . to train many leading men in the automobile industry HE best proof of the value of the home-study courses of the International Correspondence Schools is the success of I. C. S. students. This success is especially apparent in the automobile industry. Jesse G. Vincent, Vice-President of the Packard Motor Car Co., is a former I. C. S. student. So is Walter P. Chrysler, President of the Chrysler Motor Corporation. E. V. (‘‘Eddie”) Rickenbacker, Vice- president of the Rickenbacker Motor Car Co.; J. V. Whitbeck, President of the Cleveland Automobile Co.; Hiram Walker, Chief Engineer of the Chandler Motor Car Co., and John Moore, designer of the famous Ansted Motor, are also former I. C. S. students. The first step they took was to mark and mail an I. C. S. coupon similar to the one printed below. Make your start the same way and make it right now. We'll gladly send you complete information about the I. C. S. 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Aude! & Co:, 65 W. 23d St., New York City Please send me examination free coupon and full particulars about Hawkins Electrical ides Some Tire Secrets (Continued from page 66) the extra expense incurred in the change.” “But I thought balloon tires made such easy riding that you could go right up over curbstones or roll over. a brick on the road and hardly notice any bump.” “Not with balloon tires as they are made today,” said Gus. ‘“‘That applied to the early models, which looked like overgrown doughnuts and carried air at a pressure as low as 20 pounds. They rode like a feather bed, but picked up all the nails in creation, the car shimmied all over the road if you drove it fast, and the gasoline bill went up and up. The balloon tires they are making today are really a compromise between the old-fashioned oversized cord tire and the true balloon. “Of course if you were planning to keep your car for another three or four years, it might be advisable to change because of the slightly better riding qualities—”’ “I’m going to trade it in next season,” Conklin broke in. “That settles it,” said Gus. around for your new tire in the morning. Don’t forget to ask me for an old spring leaf for a tire iron.” “Looks like it’s too late to do any house- hunting this afternoon, Joe,”’ he remarked, as Conklin drove off. ‘‘We ought to get back now and see how many gallons of gas Bill has sold.” pe agreed and when they rolled up to the garage it was to find Bill engaged in conversation with a man who was just climbing in his car preparatory to driving away. “Howdy, Mr. Perkins,” called Joe. “Anything we can do for you?” “Sure,” said Perkins; ‘“‘you can make me out a receipt in full for this bill for $124.50 I owe you.” Joe got busy at once and Gus strolled over to Bill. “How did you make out, son?” he inquired. “I’m some gas salesman,” said Bill. “A whole gang of motor-campers who were traveling together stopped here and I filled their tanks while they ate up all the hot dogs down at Jerry’s stand.” “Well,” said Gus to Joe, who had strolled over, “that’s once, anyway, when we made money by trying to neglect business! Let’s take a whole day off tomorrow!” DEATHS caused by automobiles and other motor vehicles in 1924 reached the ap- palling number of 19 for every 100,000 of population. In the 58 principal cities of the United States, the increase of deaths was more than 100 over the record of the preceding year. The largest number of deaths occurred in New York City, where 1001 lost their lives. This pro- digious toll is the excessive price we pay for growing carelessness. METHANOL, a new synthetic alcohol im- ported from Germany for fuel, is as dan- gerous as wood alcohol to life, Professor Reid Hunt, of Harvard University, warns. Used improperly as a beverage or adul- terant, it will cause blindness or death as quickly as wood alcohol. “Come s simplified, complete High Course—specially prepared for come aa F s by leading professors—meets all require ] ments for entrance to college, business, and leading professions, a Over 200 not 20 Other 22": Mens and eaects tors, helped prepare the Special instruction which Courses you need for success, matter what your inelj- nations may be, you can’t hope to succeed without specialized training. Let us give you the practical training you neces. AMERICAN SCHOOL Drexel Ave and 58th St. Dept. H-775 Ol Money Back When You Finish If Not Satistic American School, Dept. H-775, Drexel Ave. and 58th St., Chicago ; Send me full information on the subject chek and how you will help me win success in that lip _Architect —Electrical Engineer —Building Contractor General Education © Automobile Engineer WW Lawyer 4 __Civil Engineer —Machine Shop P __Structural Engineer —Mechanical Engi __Business Manager —Steam Engineer ~ —C. P. A. and Auditor Sanitary and Heat __Bookkeeper —Surveyor and Maj __Draftsman & Designer __High School Grad q iy Name ..ccccccccvccccccccccccccccce ss i Address.. The Finger Prig on the Gun seer eesereseseseos ness with bute. single re sourderee A thril. | lingescape 1 a cordon of q But behind | murderer’s , er with the telltale finger print clearly. impressed on the smooth, bluedst Almost ev: tells of the aa Wh q don’t you= : ; Be a Finger Print Expert More men are needed every day. But only trained | men are wanted. We will train you ‘at Soue in | spare time, as we have trained many of America’s 5 greatest experts. ; Big Money to Experts 2," Rich rewards offered for ‘‘wanted’’ man. Unl opportunities for a professional businessof yourow® | Write at once. 7 Special Offer Now Get “tun de. tails. Also our Free book on Finger Prints, full of true stories of crime mysteries solved by our grad- uates. Professional Outfit and course in Secret Set vice Intelligence included without extra charge if youenrolinow. Write today. University of Applied Science 1920 Sunnyside Ave., Dept. 13-67, Chicago COPY THIS SKETCH and let me see what you can do with it. Cartoonists trained by this school are earning from $30.00 to $200.00 or more per week. The Landon Picture Chart Method of teaching makes original drawing v2 easy to learn at home in spare time. Send sketch with 6c in stamps for sample chart to test your ability and long list of successful students. Please state age. E LANDON SCHOOL 1451 National Bidg., CLEVELAND, 0. é q +) S For: 7 NOT A PILE , Stop Forgetting | Make Your Mind an index from which you select facts, figures, names, faces. velop concentration, strol: overcome bashful- ness. forgetfulness. Write {f todcy for FREE mpemot yan’ , concentration test and illus- ted booklet, “*‘How to Remember."’ PROF. HENRY DICKSON Dept. 929, Evanston, tll.