Popular Science Monthly 1925-08: Vol 107 Iss 2

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JUL 7 1925 ig000 F sg Contest ~See Page 29 Pi») yo | INVENTIONS I | Ul ar DISCOVERIES : RADIO Science «: AVIATION From» MONTHLY <7 HOME WORKSHOP Bucust Flying Sailboat—the Newest Marvel of the Air

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one Genuine Unless Marked Vital to every radio fan In a radio set, it is the tube that detects the sound—that amplifies the sound—that determines in large part the quality and volume of the sound. Therefore the tube— intricate of mechanism and delicate to make—is the vital spot in every set. And it always pays to be sure you use genuine Radiotrons—made with experienced precisicn. Build any circuit—simple or complex. Buy any set, plain or fancy, simply boxed or elaborately cabineted. But give it every chance to achieve its best—with genuine Radio- trons. Be just as careful when you replace tubes, too. Always see for yourself that each one bears the identify- ing marks of a Radiotron: The word Radiotron and the RCA mark. Radio Corporation of America Chicago New York San Francisco © REG.U.S. PAT. OFF. PRODUCED ONLY BY RCA

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an that the late rital 10n. lain yive dio- too. ‘ify- the August, 1925 POPULAR SCIENCE MONTHLY The Crosley Musicone a startling improvement in looks and tone over loud-speakers Already replacing thousands In camp or home, this remarkable development of radio reproduction will greatly increase your delight in radio. It is a new idea. It diffuses the sound. Upon hearing it for the first time one is at loss to locate the source of the music. Its perfection of reproduction is uncannily real. Its price, like all Crosley products, is very low because of the half-million production plans under which it is being built. Hear it at all Crosley dealers now. Crosley owns and operates station WLW, Cincinnati, the fitst remotely controlled super-power broadcasting station. Crosley manufactures receiving sets which are licensed under Armstrong U. S. Patent No. 1,113,149, and priced from $14.50 to $65, without accessories. ‘5 The Crosley Radio Corporation Powel Crosley, Jr., President 817 Sassafras Street, Cincinnati *1°7>°... Rocky Mountains Better~Costs Less © This sea! on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17. The Marvels of Radio! Incredible to those who don’t know! The Crosley 1-Tube 50 Crosley’s development of the famous Armstrong regenera- tive circuit enables you to “roam” the country and enjoy the thrill of picking up distant stations just as though you owned a multi-tube set,—all with one tube and at $14.50, without accessories, 2-Tube Crosley 51 Same as wonderful Crosley 50 with additional tube amplifier. Local and nearby ‘stations on loud-speaker always and dis- tance up to 1500 miles under average conditions. Much greater range with head phones. + ,8.50, without accessories. 3-Tube Crosley 52 A larger set for those who want greater reception range on the loud-speaker.. Operates on three tubes, using wet ordry batteries. Consistent loud- speaker range 1500 miles or more. $30, without accessories. The Crosley Trirdyn Special 3-Tubes do the work of 5 A unigue circuit combining tuned radio frequency, regen- eration and reflexed amplifica- tion that equals in results the work of 5 and 6 tubes. None re-radiating. $65 without accessories.

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SSS Ey SONOS EOE BY eb State

AUGUST, 1925; Vol. 107, No. 2 $2.50 a Year

25 cents a Copy; Popular Science Monthly The Magazine of Invention and Discovery Published in New York City at 250 Fourth Avenue y

Coming Next Month Wild Beasts at Close Range—How a daring big-game hunter made astonishing flashlight photographs of wild animals in the jungle. You won’t want to miss these thrilling pictures in next month’s issue. Secrets of Successful Gear-Shifting—Another of Martin Bunn’s fascinating “Gus and Joe” stories, in which Gus, the mechanic of the “Model Garage,” explains valuable little tricks of gear-shifting that will help you get the most satisfaction out of driving. A New Aid for Aviators—The story of a remarkable new instrument that enables airplane pilots to determine exactly the deviation of their craft from the laid-out course of flight as the result of side winds. The Fourth Set of $10,000 Contest Pictures—You still have plenty of chance to win one or more of the big cash prizes in our remarkable $10,000 ““What’s Wrong” Contest. The July Con- test is still open for entry; the August Contest appears on pages 29, 30, and 31 of this issue; and the September contest will be published next month. And, in addition, you still have as good a chance as anybody in the Grand Prize Contest. ‘Turn to page 29 of this issue and read about it. 7 More than 200 other fascinating articles and pictures, giving you all the news of radio and engineering, science and invention, strange and unusual things people are doing, together with practi- cal ideas for the automobile, the home, the home workshop, and the use of tools and machinery.

Commander Le Prieur of the French Army Avia- tion Service, with his invention known as the “navigraph,”’ which tells airplane pilots the devia- tion of their craft from the laid-out course of flight, due to side winds

POPULAR SCIENCE MONTHLY Issued cre Single copy, 25 cents. Vearly subscription to United States, its ssions, and Canada, $2.50; foreign countri mtered as second-class matter Dec. 28, 1918, at the Post Office at New York under the act 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 U.S.A. Copyright, 1925, by the Popular Science Publishing Co., Inc. The contents of this magazine 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 authori O. B. Capen, President and Treasurer; R. C. Wilson, Vice-President; A. L. Cole, Secretary.

In This Iseal | Popular Science Institute of Standards... AMivine Sapoat ..«o0s.046 = ie : iy What’s Wanted from Inventors. By Clair Price Astonishing Things about Jewels. ...... As told by R. Clifford Black Digging for the Lost Atlantis.......... By Edgar C. Wheeler The Wreck of Blimp TC-6........5..0- Perils Lurk in the Summer Sun......... By C. F. Pabst, M. D The Wonder City of the Future By Arthur A. Stuart Tear-Gas Bombs Rout Mob............ Boy Hero of African Expedition Insects in Your Back Yard Pilot Controls Speed by Sound....... A “Second Wind” for Airplanes Now Patients Drink Sunlight Roofing Plant Carried on Truck...... Portable Steam Radiator. . “Daylight” Spectacles Inv ented. Sneaks A Sun Parlor for Chickens... ........... Smoothness of Roads Tested........... POW OE OOE 6 ooo os 8 5 owe oss vce oa Gas Auto Cleaner Uses Spray......... Trailer Brake Controlled from Cab.... Removable Truck Floor. | pate ~ wl Household Aids. . . Shoe with Hollow Heel. Novel Cigarali@nter ....<.c6. cies ce cee Schoolboy Builds Model Bridge....... Harbor Telephone Station............. Dentist’s Traveling Office............ Army Mules Win Tug-of-War.......... Hot-Water Heater in Fireplace....... Bundle Carriage for Shoppers........ Scaffold Brackets Aid Carpenters... .. New Crawler Attachment............ Oil Pouring Simplified................. Magnetic Razor Sharpener............. New Achievements in Flight. . Automatic Post-Office. . ie iscope Protects Bank Vault. . . ee es ‘Mechanical Brain’ ..........<... Light Bulbs without Filame NEB. oes scccs 105 Machine Makes Drinking Cups....... a Act [wo- TUE Set... 6. 6 oc cease ce: s Fountain Pen. . lfred P. Lane Ov oi ie Your Radio Set. By E. R. Haas Latest Novelties in Broadcasting...... Surprising Facts about Tuning Coils... . “5. an <. By Thomas Vanacore Aids for the Motorist................ Are Your Headlights Safe?........... By Martin Bunn Odd Make Any Motorist Can Tackle... The Home Workshop...... Better Shop Methods...... And Other Timely Articles and Pictures Revolutionary New Propellers.......... Would You Like Their Job?.......... Dangers in Bolting Your Food. i ; : : : The Old and New in Engines......... Oddities of Motordom............... ee. Fuel-Saving Smoke-Consumer.......... Page 17 19

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Pictures August;1925 In Buying Vacuum Tubes POPULAR SCIENCE MONTHLY 17 —Look Out! Alexander Senauke, Radio Engineer of the Popular Science Institute of Standards, is shown here testing vacuum tubes on the apparatus used by the Institute. The bridge arrangement shows the internal capacity of every vacuum tube tested By Alexander Senauke, M.E., E. E. Radio Engineer Popular Science Institute of Standards | HERE is, probably, no other radio product on the market that can hide its merits or de- _ merits quite so thoroughly as a. vacuum tube. Every vacuum tube looks like _ every other vacuum tube; but, un- fortunately—or perhaps fortunately ' —they all do not pertorm alike. In ’ the case of some radio products there ‘are points of construction, etc., for which the purchaser can look, but in ‘vacuum tubes there is no distin- guishing feature that will give a clue to the efficiency of the product. Asa result, the inexperienced purchaser of radio products is quite likely to be misled by price. There are a number of tubes being sold to-day whose price compares fa- _vorably with standard tubes, but whose efficiency is not at all com- parable. Noting the similarity in appearance, the purchaser who has not suffered already by experience very likely will attribute the differ- ence in price to the cost of a “big name.” He buys the unknown tubes once—but not twice. BEFORE any vacuum tube (or other radio or tool product) can . be advertised in POPULAR SCIENCE MONTHLY, it must go through a very rigid test in the laboratories of the Popular Science Institute of Stan- ' dards. There, experts determine whether the tube will give satis- ' factory service and whether that service will last over a reasonable _ period of time. The characteristics desired in tubes are: 1. High amplification constant. 2. Low output impedance. 3. Low internal capacity. 4. Correct ratings of filament, voltage and current. 5. Filament emission that will be little affected by ordinary use. 6. Mechanical construction that will insure against (a) Excess of mi- crophonic disturbances; (b) shortening the life of the tube by ordinary use. The laboratory tests are based on these requirements. First, the tubes are inspected for construction and finish. The parts are measured in order to determine whether they fit the sockets, etc. Following this the manufacturers’ ratings as to fila- ment current and plate voltage are checked. The Engineers of the Institute next measure the voltage amplification constant, the output impedance, the La © 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. a internal capacity, and the total fila- ment emission. Where special design makes it necessary, sufficient additional labor- atory measurements are made, so that an analysis of all measured con- stants will permit of determining the suitability of the vacuum tubes for their intended application. The effect of normal abuse on fila- ment emission is measured. The tube is paralyzed purposely also, and the effectiveness of the recomnerded methods of restoration on the par- ticular tube is checked. Actual use of the tubes in their various capaci- ties in different radio receiving sets makes a final check. The purchaser of radio vacuum tubes has, then, one point to go by in judging the products offered to him. If the tubes bear the seal of approval of the Popular Science Institute of Standards they will give good service—service that has been determined accurately by the tests described above. [* 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 prod- ucts specifically advertised in Popu- LAR 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.

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POPULAR SCIENCE MONTHLY August, 1925 ele cli VI ly Sensitivity—yes. ( Clarity of tone—surely. : But selectivity—thatis the truetestof performance. The extreme selectivity of the Grebe Synchro- phase has been made possible by the Binocular ( Bi \ Coils which, because they have no field, are un- “ile mieseaenee affected by impulses from undesired stations. They | Coils keep the set automatically balanced against such interference. These Binocular Coils are exclusively Grebe, as f | are also the | Grebe S-L-F (straight line frequency) Condensers and Grebe Volume Control which are outstand- ing features of the Synchrophase. —the most important function of a radio set Ask your dealer to demonstrate these features or write us A.H. Grebe & Co., Inc., Van Wyck Blvd., Richmond Hill, N.Y. Western Branch: 443 So. San Pedro St., Los Angeles, Cal. This Company owns and. oper- ates stations WAHG, WBOQ; — -also mobile and marine low-: ~ wave re-broadcasting stations. — = TRADE, TIARK =~ rIS] This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17,

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POPULAR SCIENCE MONTHLY SUMNER N. BLOSSOM, Editor August, 1925 | A Flying Sailboat, Newest Marvel of Aviation All-Metal Seaplane Carries Masts and Canvas that Can Be Unfolded to the Breezes By John E. Lodge IGH abovethewaters of the Baltic Sea recently a seaplane soared. Suddenly it dived, straightened out within a few feet of the water, and soon was skimming the waves. Ob- servers watched the maneuver with interest that changed to astonishment when they saw two sails rise and spread their white canvas on the hull of the now floating air- plane. The sound of powerful engines was reduced by half; evidently only one wasrunning. Then that too was silenced, and the plane scudded through the water, with a snappy breeze behind the sails, as smoothly as any sailboat, though with less grace, owing to the appearance pre- sented by the two great engines raised above the hull of the plane and the wide- spread wings with their upward slant. This astonishing new type of all-metal flying sailboat pictured here and on the cover of this issue, was completed and tested a few weeks ago by the Rohrbach Metal Aeroplane Company of Copenhagen. It is constructed of duralumin and built on principles used in bridge and ship- building work, that is, of riveted girders and plates. This structure permits of larger wing spans and the use of more powerful engines. But the real feature of the Rohrbach seaplane is its ability to carry sails, a mainsail, foresail, and jib. These sails are collapsible and may be spread to the wind or collapsed at will. They serve as auxiliaries to the air- plane engines, providing an added ele- ment of safety on long cruises. Should one engine fail, the other would still keep the plane going; but should both engines fail, the sails would carry the boat along until the engines had been repaired or until help arrived. Again, should a tempest drive the plane far from its appointed course, and the fuel supply’ run low—the sails could be re- sorted to and the fuel supply conserved. Above: Rohrbach sea- plane in the air. At left: On the water with both sails set. These col- lapsible sails serve as auxiliaries to the two power- ful engines These illustrations give a general idea of the design of the Rohrbach plane. It is of the monoplane type, with cantilever wings set at an unusually acute angle, which is said to aid materially in the ma- chine’s control. The wings are so strong that the crew can walk safely along them, a feature that is of considerable value in docking. There are two auxiliary sta- bilizing pontoons situated under the wings, as well as a beaching trolley. The hull itself is divided into water- tight compartments by bulkheads and is designed so that the machine will float with any two compartments flooded. The two great 12-cylinder engines are mounted above the hull on hollow metal struts that carry the motors and propellers clear of the wing structure. They will develop a speed of 1800 revolutions a minute, fur- nishing approximately 720 brake horse- power. This newest seaplane marks a distinct new departure in aeronautics. 19

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ay Discovers Secrets of Plant Life Daniel Berthelot, world-famous scientist, using the mercury-vapor quartz lamp. which, he predicts, may He has proved that the common gases of the air, when subjected to ultra-violet light from this lamp, combine to produce the principal sugars, duplicating nature’s processes in In his experiments his eyes are pro- tected from the blinding rays by black spectacles eventually supplant the plowshare. growing plants. ; HY plant vegetables and till the WW soil when we can build factories that will actually fabricate our foodstuffs? Instead of hauling produce across the continent, why not manufacture it from its chemical constituents in the heart of the great cities in which it is to be consumed? The idea may seem fan- tastic, but the thing is an accomplished fact. I have seen such a factory in ope- ration. Ihave talked with the man who made it pos- sible. He is Daniel Ber- thelot, one of the world’s most distinguished scien- tists. In his laboratory at Meudon, near Paris, Pro- fessor Berthelot already has produced foodstuffs artificially by subjecting various gases to the in- fluence of ultra-violet light. His products have been smallin quantity, of course; yet it is because of the suc- cess of these amazing ex- periments that he was able to depict for me in an en- tirely convincing way, food factories of the future that may take the place, in a large measure, of ourfarms. Here is how Professor Berthelot describes his as- tounding achievement of duplicating in an amazing- ly simple way processes of POPULAR SCIENCE MONTHLY August, 1925 \ Factory-Made ‘Vegetables ur Future Foodp Nature’s Processes Duplicated by Noted nature that wise men for cen- turies have considered entirely beyond the power of man to fathom—processes of nature, by the way, which are connected closely with the greatest of all se- crets—the creation of life itself. Bear in mind, always, that these are the words of a practical man of science, long famous throughout the world for his scientific achievements, especial- ly in the use of ultra-violet light. “T see the factory in opera- tion,’’ he told me. “Each unit will be a large room with a low ceiling. The floor will be oc- cupied by glass tanks of great capacity. Each tank will have inlet pipes for the introduction of gases—the same gases that nature utilizes in the production of vegetable foods. Entering at the top, these gases will flow downward, and across the tank. Suspended from the ceiling will be lamps producing the rays of ultra-violet light. Inthis weird, powerful flood of en- ergizing rays, the gases will be converted French Scientist in Amazing Experiments By Norman C. McLoud into vegetable material while we watch “The process will be dramatic. Through the glass walls of the tank we shall gee something in the nature of a gentle snow- fall that will accumulate on the floor of the tank in the form of powder that constitutes our finished product—vege. table starches and vegetable sugars created in faithful reproduction of: the works of nature. ; " E SHALL see workmen in overalls, their arms and faces yellowish green under the powerful glare of. the lamps. Each man will wear a pair of gog- gles, without which he would go blind quickly. “We shall see the workers using scoops to gather the harvest. While we watch they will be filling. barrels or boxes with starch and sugar—the starch from one set of tanks and the sugar from another. If we follow these containers to the shipping platform, we shall see them loaded on trucks or railway cars and sent out to the world’s markets. The records will show that the day’s output has been equiva- lent to the yield of a large farm for Berthelot’s Garden of Wonders—A Shrine of Research Here Professor Berthelot is seen in his remarkable garflen studying the part played by insulation and humidity in plant development. The bottle contains water that is carried through tubes to the soil in the vitreous containers

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sust, 1925 ~ ” ~S ted nts fe watch, Through shall see tle snow- - floor of der that *t—vege- > sugars n of the . overalls, yellowish e of. the ir of gog- go blind ng scoops we watch oxes with m. one set other. If shipping oaded on yut to the will show n equiva- farm for dity in tainers ae 1925 POPULAR SCIENCE MONTHLY The Food Factory of the Future Our artist has pictured here Professor Berthelot’s astonishing predictions of how foodstuffs will be oduced artificially by subjecting various gases to ultra-violet light. The gases that nature uses in producing vegetable foods will be passed through great glass tanks flooded by ultra-violet light. In the tanks will appear a powder—vegetable starches and sugars—that will drop like snowfall to the floor, thence passing into containers for shipment as food an entire summer and that the tanks have given forth the starches and sugars that would come from the wholesale cultiva- tion of beets and cane.” To his fellow members in the French Academy of Sciences, Daniel Berthelot’s discoveries are as familiar as those of the Curies or the epoch-making achievements of Pasteur. His laboratory is one of the shrines of modern research, and his Jabors have brought him membership in the French Institute, the presidency of the . French Society of Electrical Engineers, and the chair of professor in the world- famous Sorbonne of Paris. ‘‘When my father indi- cated that the fabri- cation of foodstuffs was a chemical pos- sibility,”” Berthelot told me in his garden at Meudon, “‘some of his contemporaries felt tempted to regard the idea as a silly freak, as you would express it in English. Today the ultra-violet ray has made the supposed freak a matter of tangible fact. These rays have given us a process of admirable theoretical simplicity, closely akin to the methods of Mother Nature herself. In keeping with natural forces, we realize the com- position of vegetable How Rays Affect Plant Growth By exposing the test tubes, containing piant seeds, to ultra- violet light at varying intensities and for varying periods, Professor Berthelot proved that plant growth arises from purely physico-chem- ical reactions. In the four tubes A, theseeds were killed by expos- ure; in tubes B, the seeds were retarded, while in tubes C the seeds grew normally 21 foodstuffs by the utilization of light. We have proceeded on the basis that in the case of sunshine it is the light rather than the heat that produces the growth in plants. “The breathing of an animal or a human being embodies actual combus- tion and uses up the oxygen of the atmos- phere. In this combustion, the hydrogen and carbon in the body of the animal that are combined in various organic forms are reduced to carbonic acid and water vapor. Growing plants produce exactly opposite results. Under the influence of the sun, the plant takes the two gases ex- haled by animals and combines them again to form the sugars and the other hydrocarbons that are foodstuffs of human beings and herbivorous animals. “Until recently this synthetic function of green plants has not been reproduced in our laboratories. Therefore, many scientists have considered the function an essential and exclusive property of life itself. I have been able to prove other- wise. Right here in my laboratory I have demonstrated that the old theory is wrong. In other words, the changes produced by a growing plant are not the result of vital action, but arise from purely physico chemical reactions. (Continued on page 109)

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WN Se ED SEERA IN TE MAES SEE POPULAR SCIENCE MONTHLY August, 1925 Hauling in the Loaded Nets Science has come to the aid of the thousands of men who earn their living every year fishing for herring, the fore- most commercial fish. Air- planes and other mechanical devices now are being used to increase the catch. Also re- ports that herring schools in waters of North America and Europe grow smaller each year, have caused the British Government to send out scientists to find a remedy Setting the Nets Above: Blowing up the bladders that are attached to the nets to keep them afloat. At right: How the fleet operates. After receiving the plane’s sig- nal, the boats, called “drifters,”’ spread the nets, sometimes a mile or more long, held up by painted bladders. The mesh of the net is just large enough to admit the head of a herring. When a fish tries to withdraw, its gills prevent its escape Plane Aids Fishermen An airplane used to locate schools of fish. When the observer sights a school, he signals to the fishing fleet and the nets are spread for the haul. Fishing fleets of every country now use planes The Last Word in Modern Fishing In Northern Waters—Conditions such as the above are every-day experiences to the herring fishermen in winter waters. Frozen spray has covered the vessel, its rigging, and the fishing nets with a heavy and dangerous sheath of ice

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t, 1925 os n Oo August, 1925 POPULAR SCIENCE MONTHLY 23 This Boy Made Radio History By Radio from Hawaii A photograph of U.S. warships during the recent maneuvers in Hawaii, as received by radio in New York after a journey 5136 miles from Honolulu. Eight of the war-game pictures were sent by Alfred J. Koenig in record time UT in Hawaii this ££ O summer a 19-year- f ANSMITTER old youth from the .«. »9 AT KAHUKU States is becoming famous. Interested visitors crowd the wireless station where he is operating a machine that sends photographs hurtling 5000 miles across the sea, and men many years his se- nior listen attentively while he coaches them in the la- test developments in radio. Four years ago Alfred J. Koenig was an office boy. How in that short time he shot from a job of running errands to a place where he was intrusted with one of the most important experiments under- taken by a great radio corporation, is a regular story-book tale, more interesting because it is true. Like thousands of other boys, young Koenig was enthusiastic about radio. He rigged up a radio station at his home in Brooklyn, N. Y., and joined the Amateur Radio Relay League. In the daytime he went to preparatory school, but every evening found him at the Marconi Institute studying radio. When he was only 15, he passed the test for first-grade commercial operator. The name “Radio Corporation of America” had a fascination for him and he got a job in the offices. Opening letters wasn’t very exciting work, but he liked to be where people were talking radio. He kept on at night school, studying electri- cal engineering. Captain Richard H. Ranger, of the Engineering Department, had noticed him in the office. Alfred Koenig was quick and eager. Captain Ranger got him transferred to the Engineering De- partment and set him to work doing mimeographing. Gradually he was al- lowed to do engineering work. The engineers were developing amplifiers with particular reference to relay work. When the method of sending pictures by radio, invented by Captain Ranger, 4.7 POTOGRAPH : pa TRANSMITTER. | 4 AT HONOLULU | A Marvel of Radio The 19-year-old radio engineer, Alfred J. Koenig, (right) seated at the photo-transmitting machine. The 5136-mile route over which the pictures are relayed from Honolulu to New York, is shown on the map 19 MILES™ By Hyatt Gibson Ee He Flashed Photos 5000 a Miles through the Air +a was developed, Alfred Koenig was in on the ground floor. He had helped work the system out. The day when the first photographs were transmitted success- fully from New York to London, was one of the most thrilling he had experienced. HEN the corporation decided to make a second test, much more se- vere than the transatlantic one. Photo- graphs should be sent from Hawaii to New York, a distance of more than 5000 miles. Some one—a _ specialist—would have to be at the sending end who knew all about the special transmitting appara- tus, who could set it up and repair it if something went wrong. He would have to know, too, how to link several relay stations. ‘“We’li send Alfred Koenig; he can handle the job,” decided the officials, and sent him off to Honolulu with a photog- rapher and the picture-transmitting ap- paratus. The young expert met all expectations. He stopped in San Francisco and made: the relay connection between the radio telegraph system, from Hawaii to San Francisco and the one from San Francisco to New York. After completing the system in Hawaii, he spent a day testing the relays. .On the second day, photc- : art graphs of the army and navy maneuvers at Honolulu were sent to New York in record-breaking time—a set of eight pic- tures in less than 20 minutes! Photographs of the war games were relayed by wire and wireless over 5136 miles. They traveled 5012 miles by air in two wireless jumps, and the remaining 124 miles over telegraph relay wires. Since the test pictures were sent, photo- graphs have been transmitted regularly over this great distance. The process takes from 10 to 20 minutes. HOTORADIOGRAMS, or wireless pictures, are believed to hold forth tremendous possibilities, especially in the field of military communication. A pho- tograph of a message can be sent by wire- less much more quickly than the message can be transmitted by changing words to symbols. By slightly altering the posi- tion of the carriage receiving a photo- graph sent by wireless, a garbled mass of dots and dashes travels through the air, totally unintelligible without a code. Alfred Koenig will return to New York as soon as he has taught operators in Hawaii how to operate the photograph- transmission attachment. He will go back to the engineering Jaboratory and keep on at night school. “You have to study like a house-afire,” he explains, “to keep up with radio.” 3 yas ~ *. = ~ a * pe a ae Pr as FN Rede “Orde gee eee aie tara

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POPULAR SCIENCE MONTHLY August, 1925 Manless Monsters to | : Where giant searchlights turn night into day. This spectacular demonstration of New York City’s Shoots 23 Miles : defenses against aerial attack was staged recently at Fort Totten, which guards the eastern approach The most powerful a ‘ of East River. Notice how powerful searchlight beams illuminate targets for anti-aircraft guns long-range gun of its type, just per- ; eae Huge Modern Weapons May Be Dwarfed throw a 1560-pound m projectile a dis- gar gn by Appallingly Destructive Machines g N THESE pages are pictured a few of the marvelous new weapons of attack and defense developed by modern military genius. They represent the last word in war machines. Yet powerful and ingenious as these machines are, they would be helplessly ineffective beside the tremendous agencies of whole- sale destruction predicted for the next great war, if such a war comes. Scientists, inventors, and military men in active touch with the development of armaments practically are unanimous in the belief that a war of the future will be one of almost inconceivable annihilation. Death swifter than light, riding on waves of electricity and obedient to the will of master minds, they say, will blot out great cities, and even nations, almost in a breath. ‘ One who has drawn a vivid picture of such a catastrophe is Professor A. M. Low of London, internationally: known scientist and inventor, consultant to the British War Inventions Board during the World War. The “no man’s land”’ of future war, as he sees it, will be the sea, the undersea, and the air. There monstrous engines controlled by radio and obedient to human minds will strive to break through and destroy populated areas. Once the machines of either side break through Two of Uncle Sam’s seaplanes hiding behind a thick smoke screen laid down by other with their deadly gases, chemicals, and planes at Bay Shore, Md. A screen hundreds of feet high and as impenetrable to human explosives, the end will be only a matter eyes as a brick wall, can be laid down by an airplane at the rate of a mile a minute by a new : : of moments. method developed by the U. S. Chemical Warfare Service. This means of concealment, be J “ . it is believed, would be of tremendous aid to attacking planes during a naval engagement Radio control, radio communication, rs By Truman Stevens * a me 8 hb:

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t, 1925 JS ured a eapons ped by oresent ; ee ichines fective whole- e next "y men 1ent of ous in will be lation. waves will of ot out nost in ture of A. M. known to the ing the war, as dersea, engines ont to hrough 1ce the hrough ls, and matter cation, August, 1925 POPULAR SCIENCE MONTHLY and mastery of electric power will be deciding factors. Among the predicted weapons are: combined armored tank- submarine airplanes, for fighting on land, under water, or inthe air; jets of water charged with electricity to kill off all life with which they come in contact; deadly gases and chemicals; battle planes developing wire- less power to destroy aircraft within several miles; wireless fire to devastate enemy territory; wireless control of tor- pedoes, planes, ships, and submarines. “The possibilities of electricity as a lethal weapon are almost unlimited,” says Professor Low. “Men will fight not with their bodies but with their minds. Their ingenuity will be directed toward supplying them- selves with long-range weapons, respon- sive to exact control and capable of keep- ing at bay the lethal engines of the enemy equipped with facilities for the destruc- tion of whole nations at a single blow.” Modern Tanks Proof against Bombs Above is a_ spectacular demonstration of the effectiveness of modern tanks against bombs. The photograph was taken just as a bomb exploded among the First Division Tank Company during recent maneuvers at Miller Field, Staten Island, N. Y. At the right is a gigantic two-ton airplane bomb, 14 feet long. Compare its size with that of the soldier How trees were crumpled like straws before the onslaught of tanks in recent mimic warfare at Miller Field, Staten Island. There 15 great tanks rumbled irresistibly over stone walls, trees, and ditches. This picture gives an idea of the tank’s great power ct ise PRR ine Ai AE oR BT eS NECTION ARE EFA OR oes Seen taSman NTT a rs

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POPULAR SCIENCE MONTHLY August, 1925 A New Speed Rival of Plane and Auto A remarkable airplane photo graph of the Twentieth Century Limited and the Baby Gar IV in their dramatic 150-mile race down the Hudson. The speed- © International boat won the race by 24 minutes News The Motor-Boat, Victor in Race with Express, Aims at 100-Mile Goal By Ellsworth Bennett RECISELY at eight minutes be- Por seven the other morning the first section of the famous Twenti- eth Century Limited, one of the fastest trains in the world, rumbled across the New York Central Bridge at Albany, N. Y., for its daily trip down the Hudson River shore to New York City. One minute later two high-powered motor-boats, the Baby Gar IV and the Baby Gar V, flashed out from a float aimost directly beneath the bridge, and in furrows of flying spray, streaked down the river in pursuit. The shades of Robert Fulton and of Henry Hudson must have stood aghast at the dramatic contest that followed. On the shore a streamer of smoke marked the swift passage of the Twentieth Cen- tury over the rails, while out in the river long ribbons of foam streamed back in the wake of the little speed-boats as they leaped across the waters. And in the end one of the motor-boats won. After the Baby Gar V had broken down at Poughkeepsie, the Baby Gar © IV, with its owner Gar Wood at the helm, completed the 150- mile journey to New York, 18 miles—24 minutes—ahead of the express. It made the trip in 2 hours, 48 minutes— an average of 46.5 miles an hour. Some have said that it was no race at all—that the Twentieth Century starting from Albany 39 minutes ahead of sched- ule, was compelled to “‘loaf along’ the river, bound to a schedule of safe opera- tion. However that may be, the fact re- mains that this encounter passes into his- tory as an epoch-making event. For by showing that it can leave behind one of the fastest trains on the rails, the power- boat definitely has won a place beside the airplane and the automobile in an era of speed. The Victors at the Finish The speed-boat Baby Gar IV tied up at the Columbia Yacht Club dock after beating the Twentieth Century Limited from Albany to New York. Gar Wood, owner and pilot. Johnson, mechanic, Chapman, who acted as the official timekeeper In the center is At his right is Olin and at his left, Charles F. Experts are predicting that the day is not far off when motor-boats will travel 100 miles an hour. The present world’s record of 80 miles an hour is held by the Miss America II, one of Gar Wood’s boats. Two of his boats have approached a 90-mile speed unofficially. And now, with the 100-mile goal in prospect, he has announced that he expects to build a boat with 2500 horsepower—one that literally will fly across the water. Another sportsman who is aimingatthe same goal is Alexander Johnson, a New York man, who nowis building the Yankee Doodle, a speed-boat with four Liberty motors giving about 1800 horsepower.

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Sust, 1925 ito mbia tury er is Olin y eper he day is ill travel t world’s d by the Wood’s proached ind now, ct, he has build a one that oT. ingatthe 1, a New 1e Yankee t Liberty | ‘sepower. ; shaled an array of legal tal- ent and scientific experts such as might appear in the trial : of a capital case involving persons of international no- toriety. August, 1925 A Country | S:hoolmaster Stirs the World § THIS issue of POPULAR SCIENCE A MONTHLY is published, there is scheduled to take place in the lit- tle county seat of Dayton, Tenn., one of the most remarkable trials in the legal history of the last several centuries. John T. Scopes, teacher and football coach of the Rhea County High School in © Dayton; is being prosecuted on a charge of teaching the theory of evolution in defiance of a state law, enacted last spring, which forbids any instructor in the pub- lic school system of Tennessee to “‘teach any theory that denies the story of Divine Creation of man as taught in the Bible, and to teach instead that man has de- scended from a lower order of animals.’ The specific charge against Scopes is that in reviewing in the classroom a text- book on biology—a book, by the way, regularly adopted and used in the schools of the state—certain portions were dis- cussed by him in a manner that indicated his belief in the theory of evolution. Scopes was arrested on complaint of George W. Rappleyea, an engineer of Dayton, himself said to be supporter of evolution and friendly to the teacher. The complainant’s reason for causing the arrest and subsequent indictment of Scopes probably is made plain by the fact that before he acted he obtained from the American Civil Liberties Union as- surance of financial backing in defense of Scopes, both in his trial in Rhea County and in the event the case is carried to higher courts. THs is the first time since the theory of evolution was promulgated by Charles Darwin 65 years ago, that thetheory ever hasserved POPULAR SCIENCE MONTHLY The Storm Center John T. Scopes, the young country school- master of Dayton, Tenn., who goes on trial charged with teaching evolution in the Dayton high school in defiance of a state law. Some of the nation’s most noted lawyers, including Clarence Darrow and Bainbridge Colby, form- er Secretary of State have gone to his defense For example, in addition to Judge John Randolph Neal, of Knoxville, Tenn., who is in charge of Scopes’ defense, there are appearing for the defendant teacher, Clarence Darrow, one of the country’s most noted lawyers, and Bain- bridge Colby, former Secretary of State and law partner of Woodrow Wilson. Also, behind Scopes, ready to offer expert testimony in his behalf, is the entire membership of the American Association for the Advancement of Science, pledged to his support by Professor Michael I. Pupin, of Columbia University, president of the organizaton. 27 Great Legal Battle Looms in Trial of John T. Scopes for Leaching Evolution By Robert E. Martin On the other side, arrayed with the prosecution, is William Jennings Bryan, the country’s best known antagonist of evolution. Now, what is it that has caused these well-known men to enter actively into a legal case wherein a small-town school- teacher has found himself in difficulties due to his alleged disobedience of a state school statute?{ What is it that has caused what, on the face of it would seem a matter of local interest only, to assume the proportions of a national issue? According to Judge Neal, chief counsel for the defense, the question of the truth or falsity of the theory of evolution is not the issue at stake. The question to be decided, he declares, is whether freedom in teaching and learning what the great thinkers of the ages have worked out is to be maintained or denied. As such, he declares, the principles involved in the Scopes case assume tremendous impor- tance. ILLIAM JENNINGS BRYAN, on the other hand, maintains with the prosecution that it is the Darwinian theory that is on trial; that the question to be settled is whether the Bible or Darwin is to be accepted as truth in ex- plaining the mystery of creation. To many persons mention of the theory of evolution probably conveys no idea more definite than that the evolutionists hold that man is in some way or other descended from the monkeys. As a matter of fact, no evolutionist— not even Darwin himself—has held this opinion. The belief offered in 1844 by Darwin, Sir Charles Lyell, Alfred Russell Wallace, and several other British scien- tists, was that study of various biological, fossil, and other data, collected by them, indicated that reptiles were developed from fish, and birds as the basis for a court case. Moreover, we must hark back for centuries before we find another case in which, as in the present one, the principal point of issue is a conflict be- tween religious teaching and scientific opinion. These arethe circumstances that make the Scopes trial remarkable, that have focused the eyes of the world on an obscure little Southern town of 1800 inhabitants; these, and the fact that in the pros- ecution and defense are mar- from reptiles; that all nature develops in an orderly way, everything moving from a ead ST ret eee “sae seraaaegmar Se fe : aOR T eT eee Pe i a am tN i EE LIT ARTO NET — OW Me oC ie mee tana pate ERE What the Tennessee Law Says is the main text of the law under which John T. Scopes is being prosecuted for teaching evolution in the high school of Dayton, Tennessee: SECTION 1. of the State of Tennessee, That it shall be unlawful for any teacher in any of the universities, normals, and all other public schools of the state which are supported in whole or in part by the public school funds of the state, to teach any theory that denies the story of the Divine Creation of man as taught in the Bible, and to teach in- stead that man has descended from a -lower order of animals. SECTION 2. teacher found guilty of the violation of this act, shall be guilty of a misdemeanor and upon conviction shall be fined not less than one hundred ($100) dollars nor more than five hundred ($500) dollars for each offense. Be It Enacted by the General Assembly Be It Further Enacted, That any simple to a complex state. That is, instead of each of thousands of kinds of animals, insects, birds, fish, and rep- tiles being made separately, they came into being through gradual changes. In his book, “The Origin of Species,”’ Darwin described a process he termed ‘‘natural selection,” which might explain this de- velopment, pointing out how accidents, disease, starvation, and other factors weeded out the weak in every kind .of plant and animal. Thus, only the fittest were left to produce new generations each year, (Continued on page 114)

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I POS RNOLD NLD ITE IRE

eS 28

POPULAR SCIENCE MONTHLY August, 1925 When Airplane Landing-Gears Crash Machines Dropped in New Safety Tests—By E.F. Bacon

- Mined teGEELE Ma hoe Y pee The Shock-Recorder Shocks to which the landing gear is subjected are recorded by pin pricks made by a series of sliding spindles, governed by adjustable springs and weights, which are shown above ITH the continued increase in \ \ flying speeds, and consequent in- crease in landing speeds, the prob- lem of safety in landing is one that is engaging the best efforts of aeronautical engineers. Safe landing depends not only on the skill of the pilot, but on the strength of the airplane’s structure. Even the most expert pilot is unable to prevent rough landings under adverse conditions. A forced landing on rough ground, a sudden gust of wind at the moment of landing, or a quick swerve to avoid an obstacle, may cause violent stresses on the landing gear. Structural failure under such conditions a Rn ed pea Fe oe ali ‘prank eel Bk ses ee 3 “ee Mes sae Pi eS 2S : 3

How the Test Is Made An actual test with the new apparatus, showing collapse of the landing gear. The nose of the fuselage is lifted by block and chain and dropped from increasing heights, varying from 12 to 40 inches until failure finally occurs means partial or total wreck of the plane. To determine exactly the ability of landing gears to stand up under various loads and thrusts, the Engineering Divi- sion of the U. S. Army Air Service re- cently standardized the testing methods pictured on this page. The airplane to be tested is stripped to the fuselage, then loaded with bags of shot representing the weights of motor, wings, and equipment. With the tail of the machine supported on a scaffolding, the nose is lifted verti- cally by a block and chain until it reaches a certain height. Then, by means of a trigger release hook, it is dropped suddenly on an inclined plat- form designed to sim- ulate a cross-wind landing. In this man- ner the fuselage is dropped successively from increasing heights until failure occurs. The drop varies from 12 to 40° inches, according to the type of plane. To determine ac- curately the live loads at which failure oc- ESS

fi. ¢ COLLARS ## SPINDLE #

ZANE ZZZZZ_ a \LLLLLLLL LL fl PIN PRICKS

Her] etsessssssSletess S: an Diagram showing construction of the shock-recorder. The posi- tion of pin pricks on a paper record registers the amount of shock to the

Where the Break Came Failure of the landing gear is seen clearly in these pictures of the test. In the second picture the fracture of a strut is visible. ‘The second and third views show the rebound of the machine and collapse of the landing gear curs, and to obtain comparative data on shock-absorbing systems, a shock-re- cording instrument was designed. This consists of a pair of circular plates with holes, through which a set of spindles, fitted with needle points at their lower end, is free to slide. The movement of each spindle is governed by weights placed on top of the spindle and by an adjustable coilspring that fits loosely around it and is fastened to a collar locked to the spindle. Clamped to the low- er plate is a circular recording paper. The record of a shock is made by small hols that are pricked in this paper by the points of the spindles as they plurge down- ward in response to an impact. Since, by varying the compres- sion of the spring, each spindle can he set to record a definite acceleration of grav- ity, location of the pin pricks on the rec- ord tell the story of the shock to which the landing gear is subjected and valua- ble data are obtained,

RECORD

PAPER DISK

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landing gear

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18USt, 1995 1ame seen clearly t. In the of a strut is hird views achine and gear tive data shock-re- d. This ates with spindles, eir lower ement of its placed djustable id it and 2 spindle. o the low- _ eirculer per. The shock is all holes icked in by the spindles ze down- ponse to Since, by compres- spring, - can he 2 definite of grav- of the the rec- story of 0 which gear is d valua- ybtained, ‘August, 1925 POPULAR SCIENCE MONTHLY Here are the three judges who will award the prizes in POPULAR SCIENCE MONTHLY’S $10,000 “What’s Wrong” Contest, at work examining entries. From left to right they are: Alexander Senauke, M.E., E.E.; Prof. Collins P. Bliss, and Dr. Hazen G. Tyler You Still Have Time to Win in Our Great $10,000 Prize Contest RE you observant? Are you alert? A If you are, here is an opportunity to win one or more cash prizes in our $10,000 ‘“‘What’s Wrong’ picture contest. As you probably know, the contest was announced in our June issue, but with 512 awards yet to be made, there is still a chance for everybody. You can start now. The idea is simple. It has to do with John and Mary Newly- wed and their enthusiastic but in- one set of answers to any picture, and if so, how answers should be submitted. The rules of the contest, which appear on page 110 of this issue, state that con- testants may submit as many answers as they wish for pictures in either the Monthly Contests or in the Grand Prize Contest, provided they are submitted in good faith. Additional answers for any picture, however, should be sent in as separate entries. In other words, you can submit as many different sets of answers for the pictures as you wish. In cases where an individual submits more than one set of answers, the judges, in considering awards, will select the set of answers that is most nearly correct. The three judges who will decide on all awards are shown in the photograph at the top of this page. They are: Prof. Collins P. Bliss, Director experienced efforts to do odd jobs of the Popular Science Institute about the house. Eight pictures are published each month. Each shows something wrong in the way a job is being done, and in addi- tion, the artist has drawn one thing in each picture incorrectly. What you are to do is to find the mistake the artist has made and also tell what John or Mary is doing wrong and why it is wrong. You will find the contest fasci- nating and profitable. It costs nothing to enter. It is open to every one, everywhere. Mem- bers of your family and your friends all can take part in it. And you can submit as many sets of answers as you like. Remem- ber, you have until July 30 to submit your answers for the pic- tures published in our July issue and until August 30 to solve this month’s puzzles. Take the first picture in the August contest on the next page, for example. There John is seen hanging a screen door. What is it that he is doing wrong? What error has the artist made? Study the picture carefully, then answer these questions briefly and clearly. A number of: contestants have written us asking whether they You May Win One or More of These Big Prizes OPULAR SCIENCE MONTHLY is awarding $10,000 in 580 cash prizes for the best answers submitted in this great contest. The cash prizes in each of the four monthly contests are: Pivot Prigme................. $500 Second Prize............... $100 Tree PRIMO... ..... ce ceeucs $50 5 Prizes, $10 each............ $50 60 Prizes, $5 each.......... $300 Total, four months....... $4000 In addition, cash prizes in the Grand Contest will be paid as follows: First Grand Prize......... $2500 Second Grand Prize....... $1000 Third Grand Prize......... $500 5 Grand Prizes, $50 each. . . $250 50 Grand Prizes, $10 each. . $500 250 Grand Prizes, $5 each. $1250 Total Grand Prizes........ $6000 of Standards and head of the Department of Mechanical En- gineering at New York Univer- sity; Dr. Hazen G. Tyler, Asso- ciate Director of the Popular Science Institute of Standards and Associate Professor in charge of Experimental Engineering, New York University; Alexander Senauke, M.E., E.E., Radio Engineer of the Popular Science Institute of Standards. The deci- sions of these judges will be final. The third set of pictures, com- prising this month’s contest, ap- pear on the two following pages. If you have misplaced your copies of the June and July issues of POPULAR SCIENCE MONTHLY containing the first two sets of pictures, copies of these issues may be examined free at the offices of this magazine or at public libraries. Or, if you wish, you may obtain copies at 25 cents each from the Picture Contest Editor, Popular Science Monthly, 250 Fourth Avenue, New York City. The fourth and final set of contest pictures will be published next month. Watch for the Sep- tember number, on the news- are allowed to send in more than stands August 10. COMPLETE RULES FOR THIS SENSATIONAL “WHAT’S WRONG”? CONTEST ON PAGE 110

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AARNE Seteeteert habe eee ina alae racks ee Se ee 30 POPULAR SCIENCE MONTHLY A $10,000 Test of Observation and Alertness August, 1925 What’s Wrong in In Each John Is Doing Something Made One Error 1 When.-a high wind tears off the old back screen door, * the Newlyweds decide to get a new one. Fitting the door isa job that John undertakes with more relish than experience Dae yd Mary complains that the compression faucet in the °* washtub leaks. John says a new washer is needed, and is delighted to try his hand at such a simple plumbing job a ey gg mer s\4 | AGS ale sig, 07 a hens 2 a 3 With Mary steadying the board, John finds double * enjoyment in nailing up a shelf in the bedroom closet, even though he is not quite sure how it should be done New linoleum for the kitchen floor arrives and John enthu- * siastically sets to work tolay it. Here he is tacking down the first width, while Mary watches from the side lines spd RRS pliable Augus

Page 19

st, 1925 Les

August, 1925 POPULAR SCIENCE MONTHLY 31 ' > Read the Rules These Pictures? 7)"hus Amada Wrong, and in Each the Artist Has Contest—Page110 in the Drawing

5 Mary superintends while John paints the drop-leaf table. 6 One of the dining-room windows refuses to stay up. This * When he finds the paint too thick to spread properly, he * gives John his first experience in removing the window gladly adopts her suggestion for an easy way of thinning it stop and replacing a broken sash cord with a new one

E tee . di —< & tere ee? :

7 The engine of the Newlywed’s coupé starts to miss—an Although a novice, John determines to repair some ugly * excuse for John to tinker with the spark plugs. Here he * breaks in the cellar floor. Here he is storing the cement is shown adjusting the points, using a half dollar as a gage behind the garage until he can find time for the job

OR ra ee a

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POPULAR SCIENCE MONTHLY A Thrilling Haul! Sky Nets to Capture Planes

signed to catch enemy air- planes, form one of the latest and most spectacular developments in anti-aircraft defense. Devised by a Japanese inventor, Takeo Takagi, they now are being tested by the Japanese army and navy. Fastened between parachutes, the Pi siened to ext of the sky, de-

nets are shot upward in bombs. When the bombs burst high in the air, the parachutes open, spreading the nets in the path of enemy airplanes. Here our artist presents a dra matic picture of how the net is de signed to foul the propeller. The lower picture shows a net on the ground with parachutes attached.

b=] pads eesog =p <q Sw So J os

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August, 1925 POPULAR SCIENCE MONTELY hats Wanted from Inventors Here Is a Remarkable Record of Hundreds of Opportunities for Your Constructive Genius By Clair Price genuity of inventors are contained in a red-bound memorandum book that lies in the members’ room of a suite of offices in London, England, occupied by a patentees’ mutual aid organization. Although it embodies an idea as unusual as it is useful, the book is as commonplace in its outer appearance as an ordinary ledger. Only the gilt letters of its title, “What’s Wanted,” indicate to the casual Dien: of all sorts upon the in- In the case of others—for instance, a pipe that can be cleaned easily and effectively—a comfortable little sum is waiting. All of them, from the demands whose fulfilment would revolu- tionize industry downto the hum- bler wants of the man in the street, may be found jumbled together in the crowded pages of ‘‘What’s Wanted.” If brevity is the soul of wit, there are few pages more This is the most remarkable memorandum book in the world, its pages filled with needed inventions under the heading of electricity and wire- less. This is no doubt a correct reflection of our industrial civilization in this year of grace, 1925. visitor that its contents are far from commonplace. - Manufacturers, scientists, research workers, members of the British Parliament, house- wives, and the plain man in the street have written their wants in it. London inven- tors have formed the habit of consulting it in search of ideas for commercially promising inventions. Asaresult “What's Wanted” presents a remarkable view of the wide scope of present-day inven- tive science, for the demands made through this unique book vary from a method of utilizing atomic energy to such humble wants as an effective means of rooting up dandelions from the lawn. N SOME of these wants * there are decades of work for laboratories with the most advanced and complete equip- ment. In others, no more is needed than the flash of a new idea and a pair of ordinary, capable hands to carry them _out. Some of them are far beyond the resources of the average inventor. Others are suited to the humbler wits of any of us, whether we are in- ventors or not. For the pro- duct of the man who can meet any of them there is a real de- mand, else they would not have found their way into the pages of ‘‘What’s Wanted,” There is money waiting for the in- What Would You Like to Have Invented? OESN’T it strike you that the ‘What’s Wanted” book described by Mr. Price in this article is a great idea? That’s just the way it strikes us. And so we are going to copy the idea. We are going to compile an American ‘‘What’s Wanted” book. This book we will place on a table in the home of PopuLaR SCIENCE MontTuiy at 250 Fourth Avenue, New York City. There it will remain always open for anybody to enter his wants in black and white. There, too, it will be open to inventors everywhere, who come to it for sug- gestion and inspiration. If you live at a distance and have a want to enter, simply mail it and we will enter it for you. Already we have a most interesting nucleus for our book; for on its first pages we are entering needed inventions suggested in letters from a number of interesting persons, among them Houdini, the world famous man of magic; George Gordon Battle, noted New York attorney, and Dr. David Starr Jordan, chancellor emeritus of Leland Stanford, Jr., University. Can’t you imagine the fascinating possibilities that such a volume holds? Any day—who knows? —an idea caught at random from its pages may lead to an invention which, like the steam-engine and the automobile, may transform the very world we live in.—TueE Epiror. What Britain wants from her inventors is, first, im- provements in the young science of wireless; second, domestic and general house- holdimprovements and, third, improvements in internal- combustion engines, new sources of power, and new methods of power transmis- sion. Toa lesser degree, the English people are interested in nautical, chemical, and phonetic improvements. ASTLY, there are im- provements wanted in the realms of the airplane, office methods, lighting, heating, and metallurgy. This, it might be emphasized, is the order in which England is making its demands upon the ingenuity of its inventors. A list of similar American warts might vary the order some- what, for labor-saving devices of the domestic and general household sort are more ad- vanced in the United States than in England. These, according to“ What’s Wanted,” are some of the improvements that Great Britain is asking of her in- ventors in the realm of elec- tricity and wireless: A means of transmitting wireless power of sufficient capacity for transforming into mechanical energy. An efficient method of vary- ventor who can cope with any of these wants. In the case of a few of them—the harnessing of the sun’s electromagnetic waves, for instance—there are millions awaiting the successful inventor and a Position in history possibly greater than that of the man who first harnessed steam. packed with wit, more abruptly eloquent, than the scribbled pages of this unique volume. If we attempt to straighten out its jumbled miscellany into some sort of order, to classify its hundreds of wants under general headings, it will be found that the largest number of them fall ing radio oscillation frequencies over an almost unlimited range. A loudspeaker that is controllable with- out distortion. Improved methods of electrical storage and power transmission. . A loudspeaker free from the “phono- graph effect.”

Page 22

. : E ' | YSERA TOAST LGR Elimination and control of atmospherics. Wireless television. More selective methods of reception. Elimination of voice distortion in wireless receivers, amplifiers, and tele- phones. A receiving valve (vacuum tube), the effective anode-filament resistance of which is about 1000 ohms. paged directive reception from only one fixed direction with possibility of altering direction at will. Neutralization of internal capa- city coupling inherent in triode valves. More knowledge of the effects and constitution of the heavy side layer. The true theory of crystal rectifi- cation. A long-life du!l emitter filament. A different class of inventor will be interested in the domestic and general household wants that are sprinkled through the pages of ““What’s Wanted.” A key that will not lose its iden- tification. A pipe that can be cleaned easily. A temperance drink that will keep and yet not pall on the palate. A means of removing old paint. Greatly simplified clothing, not strange in appearance. A cheap house-warmer that can be fitted by any one. A plan by which house refuse can be easily and cheaply destroyed at home. A COOKING range that is efficient, i.e., that usefully applies a reasonably large percentage of the heat of combustion of the fuel supplied. A fire grate giving the open-fire effect without wasting the major part of the fuel consumed. An electric toaster that will, if possible, cut off the current just before the toast begins to burn, or, if that is not possible, that will give some audible indication in time to avoid spoiling the toast. A tie presser and stretcher for men’s ties, which will take at least 20 ties at a time. A dandelion extractor. Under the heading of internal-combus- tion engines, new sources of power, and new methods of power transmission, there is work for the most brilliant and best equipped inventors: A motor engine of one pound weight per horsepower. POPULAR SCIENCE MONTHLY A light, efficient, slow-speed internal- combustion engine. An internal-combustion turbine. (a) Wind turbine electro plant. (b) Water turbine electro plant. (c) Crude- oil engines for use in tractors and road vehicles. A method of reducing friction. A practical method of making use of the power of the tides. j i i 2 Fa oe Othimags mat thon 9%. ' fone: pom ecm site, os 24, Dn ef fern mation offs pee ye Reduce Creche trim. hae ee ee Rays ili OT vee lewwrg Che sn Bh) REE Linahk Somalis Minin -mbretlhn ole tov’ dye bain la: gre er te el ae A Page of Entries Above: Entries written in “What’s Wanted,” by Prof. A. M. Low, distinguished British scientist. Left: Capt. C. Drury Coleman, secretary of the Institute of Patentees, entering letters Harnessing the sun’s electromagnetic waves. A method of utilizing atomic energy. Inventors of aJl degrees of achievement and equipment will find attractive ideas in a few of the other demands that are voiced in the pages of “‘What’s Wanted.” Means whereby a ship’s officers can inform themselves of the position and movement of approaching ships and so avoid collisions. Improved ships’ davits. A safe method of stopping ships from rolling, or at any rate not more than afew degrees in the roughest weather. A process for instantaneous color pho- tography. A chemical thermostat that will operate as efficiently and permanently as the thermostat that keeps the human blood temperature at approximately 99° F. and the blood of other animals at various temperatures. Refractory materials for lining steel melting furnaces and ladles that would be absolutely unattracted by erosion of the molten metal or corrosion of the various metallic oxides formed during the steel melting process. A noiseless gun. A motion-picture film that will speak. Non-resonant telephones. A noiseless airplane. An airplane that can be safely and aig Kacfrrimand mnt ie fo ectin ral othage 2% a nae tad horn wean d WRF 003 he fad. August, 1925 easily managed either by a boy or a girl A method of conveying speech directly and readably to paper. The discovery of the mechanism that enables us to remember almost instantly in our brains without going through the mechanism of the card index and equiva- lent systems. A furnace that will conserve 95 per cent of heat. A heat insulator, having as nearly as possible the strength of meta] which can be screwed and turned like metal and which, while ingy- lating the heat of one from the ' other, will make a perfectly strong : and reliable connection between two pieces of metal. The insula- tion must stand up to both dry and wet heat. Motor headlight that. satisfac- torily lights the road surface with- out “‘dazzling’’ approaching drivers, Some form of lighting appliance capable of penetrating fog. A method of eliminating rust. An alloy, ferrous or non-ferrous, possessing 50 per cent to 100 per cent higher tenacity than a known alloy without being brittle. A glass that will bend. A means of inducing and prevent- ing rain. More knowledge of the transla- tion of mechanical power into musi- cal tone. Credit for first suggesting the usefulness of ‘“‘What’s Wanted” belongs to Sir William B ill, whose short, silver-haired figure has been one of the fixtures of the House of Commons for the last 25 years. Less than two weeks after Sir William’s suggestion was made, the book itself was placed in the mem- bers’ room of the Institute of Paten- tees. ‘‘What’s Wanted” then con- tained a title page, Sir William’s preface, a letter from H. G. Wells, and a list of 15 wants that its donor had mentioned at the Institute’s annual dinner. The rest ot its 200 rages were empcy and waiting, but its donor’s idea soon took hold. Professor A. M. Low, a distinguished British scientist, was one of its earliest contributors and the list of 29 wants that he has committed to it is even now the longest single list it contains. Other contributors soon followed, most of them individuals, a few of them corporations. Thus far the British Broadcasting Com- pany is the largest contributor among British corporations, and most of the wireless wants appear above ‘B.B.C.” HE mails began bringing in wants to be copied into it. Individuals began climbing the two flights of stairs at 44 Great Russell Street, opposite the massive time-blackened front of the British Mu- seum, to write their wants in it. Most of these persons are Londoners, but an in- creasing proportion are foreigners. The Institute is a mutual association through which inventors supply them- selves with technical, legal, and commer- cial advice in the development and marketing of their work, but ‘“‘What’s Wanted” is open to anybody, member or non-member, who knows of a specific demand worth an invenior’s attention.

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st, 1925 2 girl, lirectly m that stantly igh the equiva- 95 per s nearly metal, turned le insu- om the ’ strong et ween insula- dry and satisfac. 2e with- drivers, opliance rust. ferrous, 100 per han a brittle, orevent- transla- to musi- ing the Vanted” , Whose as been - House last 25 fter Sir ade, the 1e mem- f Paten- 1en con- preface, ist of 15 oned at The rest waiting, ld. guished earliest nts that now the Other of them rations. g Com- among of the BC” vants to s began s at 44 massive sh Mu- Most of f an in- ociation r them- ommer- nt and ‘What’s mber or specific ition. August, 1925 POPULAR SCIENCE MONTHLY Astonishing Things an Expert Has Learned About YOUR JEWELS e as told by R. Clifford Black to Newton Burke OST New-Yorkers of the last M quarter century remember the late “‘Diamond Jim” Brady, one of the most advertised men of his time. Newspapers and many periodicals had articles about his jewels and his love of the theater, and through them he was known throughout the United States. Literally ablaze with jewels, this eccentric business man sat in the front row at every theatrical first night. He had 44 com- plete sets of jewelry, mostly diamonds. These included even diamond buttons for his underwear. The most unique of his jewels was what he called his ‘‘transportation set.” He used to wear this to railroad directors’ meetings. ‘The pieces were of platinum studded with diamonds. The shirt-studs were in the form of a bicycle, an auto, an airplane, and a buffalo, each 11% inches long. His watch chain was made of inter- locking wheels each set with diamonds. One cuff-link set was a diamond tank car and a coal car; a second set was a freight car and a passenger car, each two inches long. His leather pocket-book was orna- mented with enormous initials of diamond mermaids and dolphins. His eye- glass case was a huge locomotive set with diamonds. A big belt-buckle consisted of a wheel flanked by two tigers. The ornament of his finger ring was a wheel 1'/, inches in diameter. In the center was an enormous blue diamond which, al- though not one of the largest in existence, was one of the most val- uable because of its beautiful color. ‘6 ands ee re Oo — Raia 35 Peeling, a Pearl to Expose Its Hidden Beauties A pearl is formed in layers and when outer layers are poor in color or damaged, they may be peeled off until a beautiful inner layer is revealed. Here is William Herries, American pearl expert, peeling a pearl. Mr. Black, sponsor for this article, who is an international authority on jewels, points out that this is one of the most delicate tasks in the world, since there is a chance of ruining the pearl in the process. Only four men in the United States can do it successfully His diamond tie-clasp was in the shape of. a camel. He used a lead-pencil of solid platinum set with diamonds. The watch had a wheel design set in diamonds. The whole of the unique set weighed five pounds. But “Diamond Jim,” with his pounds of jewelry, was a remarkable exception. The World’s Largest Blue Diamond Here is the largest blue diamond ever discovered, brought to the United States by Black, Starr and Frost, the well known New York jewelers. It weighs 127 ca- rats, and is said to be a perfect stone “Diamond Jim’s’? Remarkable Set of Jewels Part of the amazing “transportation set” of jewels worn by ‘‘Diamond Jim” Brady, New York financier, when he attended railway directors’ meetings. They are of platinum studded with diamonds, and each piece represents some method of transportation Most men care little for gems. Give a man a watch and he is well satisfied. His wife can display the family jewels. Of the $450,000,000 spent for gems by Americans yearly, about 95 per cent is for the adornment of women. Women always have liked jewels. Did you notice newspaper accounts of the ex- cavation of Kish recently by the Field Museum-Oxford University expedition in Mesopotamia? Kish was the colossal Sumerian capital that flourished 3000 years before Christ, long before civilization in Egypt. The Chicago excavators dis- covered a magnificent palace, and in the boudoirs of the court ladies were quantities of ornaments deco- rated with the same stones that we consider precious today. R hsede! what causes people to at tach tremendous value to bits of stone is one of the mysteries of humannature. Money haschanged during the centuries, but the value of jewels has remained fairly con- stant. In times of uncertainty for- tunes are saved by converting money into jewels. A dealer came to me two years ago and said, “ Mr. Black, I have a lot of emeralds here that I can sell cheaper than any one else.” I asked him where he got the gems, and he told the following story: During the war the gem miners in the Ural Mountains in Russia were unable to dispose of their jewels. A Russian emerald cutter foresaw the revolution that was coming and bought right and left of emeralds.’ He purchased a freight car, and had it fitted up with comforts. When - the revolution started, he and his family began traveling in this freight car across Siberia. He hollowed out a log that lay by the stove in his car and into this put all of his emeralds. As he was known to be a man of money, the Bolsheviks searched the car (Continued on page 112)

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Ao nt a a lh IE POPULAR SCIENCE MONTHLY August, 1925 through the Ages for “enum ae “ts Ie Sifting Traces of Prehistoric Man Count Byron Kuhn de Prorok, leader of the Franco-American expedition in northern Africa, sifting for prehistoric flints in the river-bed of Oued El Abied. In the desert wastes he seeks to uncover the buried remnants of a lost continent under the sands of the Sahara, and from other towns believed to have been submerged in the sea for untold ages, scientists today are at work to patch together bits of fascinating history which, they hope, may at last give an answer to the world’s greatest mystery—the legend of the Lost Continent of Atlantis. Over trackless desert wastes of Tunis and Algiers, and along the historic African shores of the Mediterranean, a Franco-American expedition of arche- ologists, under the leadership of Count Byron Kuhn de Prorok, has been follow- ing a trail of dead and buried cities that flourished thousands of years ago. This trail, they hope, may lead them to the discovery of the birthplace of civiliza- tion, a “vanished continent’? from which emerged the culture of the ancient Egyptians and Phoenicians, and which cradled a mighty race of people. This remarkable scientific adventure NROM long forgotten towns buried promises to become one of the most romantic gam- bles in archeology ever undertaken. That it will abound in fascinating mys- tery and rich discovery already is indicated by the most recent reports of the expedition from Djerba Island in Tunisia. In the rushing tides of a narrow channel that separates this classic ‘Island of the Lotus Eaters” from the mainland, deep-sea divers under the direction of Count de Prorok have begun the search for a mys- terious ancient city believed to have been engulfed centuries ago by the Mediter- ranean. The search is based on state- ments of native sponge-divers, who say they have watched the fishes playing among fantastic ruins of the city 50 feet under water and have seen houses with walls 15 feet high, intact stairways, streets, and many-colored columns. A swift tidal current running through the channel thwarted the first attempts of two professional divers. Later, however, six divers exploring different parts of the channel all reported seeing much pottery, most of it solidly incrusted in the bed of the sea. They brought up 14 fragments, several of which i Across the Desert Wastes Part of Count de Prorok’s expedition crossing the Sahara in a six-wheel motor-car in search of long-forgotten towns buried in the desert Scientists Search the Shifting Sahara Sands for the Key to the World’s Most Alluring Mystery By Edgar C. Wheeler are 15 inches long, with mouths and handles intact, forming parts of large urns. All were covered with beautiful marine growths. How ancient this pot- tery is remains to be determined. Mean- while the hazardous diving operations are continuing. | hers more alluring, perhaps, is the ultimate goal of the explorers—a mysterious hill-bordered tableland known as the Hoggar Plateau, lying 1000 miles across the desert in an almost inaccessible spur of the Atlas Mountains. Because of its unusual formation, this unexplored plateau long has been associated with Plato’s fabled description of Atlantis, where dwelt a race of supermen who gave to the world the arts of civilization before the continent was swallowed up “‘in a day and a night” by the waters of the ocean. Count de Prorok is staking his hopes on the theory that the desolate Hoggar Plateau is the remnant of the submerged continent. He believes it possible that here man first emerged from barbarism, and that colonists who went out from here eventually formed the ancient Egyptian civilization. He hopes, too, to find here a definite answer to the question whether prehistoric men, whose remains

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it, 1925 yr sing arch sert y » ee ; and large utiful 3 pot- flean- itions s the Ts—a nown miles ssible ise of lored with antis, gave efore a day cean. es on ggar arged that rism, from cient 0, to stion 1ains August, 1925 the Lost Atlantis have been discovered in France, came, as some scholars believe, from Africa before the sea filled the Mediterranean basin. May it not be possible that the same deluge that engulfed the supposed sub- merged city at D jerba also swept the land that is now the great desert to the south, and that the sand of the Sahara once was the floor of a sea? And before the floods came, may not this same Sahara have peen part of the lost Atlantis? May not the waters have receded after their de- struction, leaving the bleak tableland of Hoggar rising from a sea of sand? OT many years ago such an expedi- N tion would have been regarded al- most as an absurdity. Then the story of Atlantis, handed down through the centuries, was regarded as a myth. Today, however, science has learned that in the alluring legends of the ancients lies a vast storehouse of knowledge. Just as the “myths” of Troy and the Tower of Babel have been revealed as realities, so now we are quite sure that the tradition of the Deluge was more than a fable. Science tells us that 10,000 years ago, or perhaps 30,000 years, this great catas- trophe overtook the world. Just at a time when the first true men were fashioning the beginnings of civilization, the Atlantic Ocean leaped its banks and engulfed them. Swollen through the years by melting ice sheets of the last Glacial Age, the mighty waters tore through the hills at Gibraltar and poured down upon those primitive people, de- stroying their settlements, burying the fields they had learned to cultivate, and finally rising through the valleys until the waves lapped the mountain cliffs. A North African Ferry One of the expedition’s cars riding on an Arab dhow near Djerba Island, where the expedition is searching for a sunken city submerged in the Mediterranean POPULAR SCIENCE MONTHLY And then, thousands of years later, perhaps six or seven thou- sand years ago, after the waters had receded, we find a brown- skinned people establishing par- allel civilizations in fertile lands close to the shores of the inland sea—the Medi- terranean. We find the Sumerians in Mesopotamia, in the valley of the Tigris and Euphrates, and the Egyptians in the valley of the Nile. And, what is strangest of all, we find traces of the same sort of people and the same sort of culture, distributed in far separated lands—in India, China, Central America, Mexico, and even in Eng- land. Distinguishing this culture are certain common Unearths Ancient Urns from Carthage Abbe’ Chabot, noted archeologist and authority on Phoeni cian inscriptions, digging ancient Punic urns in Carthage characteristics, such as the building of crude stone (megalithic) monuments, the making of mummies, and the use of the symbol known as the ‘“‘swastika”’ for good luck. In the old Maya civili- zation of Yucatan, for ex- ample, have been found many of these customs and ideas, very similar to those of the Egyptians. The custom of mummification runs through Central and South America. In Guatemala there is a river Nil (Nile) on the banks of which are pyramids. And only a few weeks ago, in the ruins of a buried city uncovered from the side of a hill near Arangaricuaro, Where Men Roamed before the Dawn of History Members of the de Prorok expedition passing on horseback throug’: the gorges of Seldja, Tunisia, where prehistoric flints already heve been found in the bed of a river flowing through the magnificent gorge Mexico, there were found idols that are strikingly similar to idols of ancient Egypt. Where did these people, so widely dis- tributed, come from? What was their common origin? In his attempt to establish that northern Africa was the cradle of civilized man, Count de Prorok early this year undertook the excavation of the sites believed to cover the ancient Phoenician cities of Utica and Carthage. In Utica, temples, villas, tombs, and countless relics of civilizations that once flourished in northern Africa already have been uncovered. In Carthage he claims to have unearthed an Egyptian culture that preceded the Phoenicians by at least 500 years, andto have found traces of at least half a dozen succeeding civilizations. (Continued on page 111)

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POPULAR SCIENCE MONTHLY August, 1925 The TC-6 nosing into the ground a few seconds before the bag was torn apart by the wind. Soldiers are seen scurrying to get out of the way The Wreck 0 the T'C-6 HESE remarkable exclusive photo- graphs are probably the first ever made of the collapse of a dirigible in the air. They were snapped by an amateur photographer at Fort Crook, Omaha, Nebr., just as a high wind snatched the army dirigible TC-6, bumped its nose on the ground, and ripped the great bag in half. Warned that a storm was brewing, 200 soldiers had been rushed to the ship to hold it down. The officers, believing they might ride out the storm, hurriedly climbed aboard. The motors were slow in starting. As the wind rose in fury, Capt. E. W. Hill saw it was futile to try to take off. He shouted to the crew to let go and get out of the way, and the officers jumped from the cabin. At the same instant a terrific gust hit the bag and ripped a great hole in the rear. The ship crashed, nose first, and as the bag collapsed, the rudders, torn from the rear, were hurled 50 yards. Among the spectators was Walter S. Johnson, an insurance agent, carrying a small pocket camera. Although little experienced in photography, he snapped four spectacular pictures of the collapse in two minutes. ao The tail of the dirigible, torn off by the storm, photographed as it was falling to earth. was carried 50 yards. At the left may be seen the rest of the blimp as it settled on the ground, a shapeless mass. Luckily, no one was hurt. These remarkable photographs were snapped by one of the spectators who happened to have a pocket camera with him Av adWdgnanae — ft a— Hm ef st ee et OL, ~~ —_ a

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Bust, 1925 "eal ) one aphs who August, 1925 POPULAR SCIENCE MONTHLY 39 Perils Lurk in the Summer Sun How Your Desire for ‘‘a Good Coat of Tan’’ May Cost You Serious Illness or Even Death — By C. F. Pabst, M.D. NE night last summer I O was called to attend one of the worst cases of sun- burn I ever have seen. The patient was a young man who had spent the day at a bathing- peach and, like many persons whose opportunities for outings are few, had made the most of his time, remaining in his bath- ing-suit for hours under the broiling midsummer sun. Now he was paying for his indiscretion. His face was fire- red and swollen. His arms, shoulders and legs literally were scorched, just as if he had ex- posed his naked body to the i heat of a blast furnace. re His eyes were narrow ee slits. He age xs was nause- Pe Bile a er ated and —— had a high fever. He screamed with pain when I attempted to treat him. For three days he remained in bed, deathly ill and scarcely able to move. His was an extreme case, and yet it was typical of thousands of others that come within my own and other skin specialists’ experience every summer. For few per- sons seem to realize that a severe case of sunburn actually is a dangerous affliction that causes not only excruciating pain, but may permanently affect the health, cause chronic skin diseases, and even result in death. So little do people understand sunburn that they often martyrize themselves by deliberately burning their skins, not for the beneficial effects of sunlight, but to acquire a ‘‘coat of tan.” An office worker goes to the beach for a week-end. He decides to get a ‘‘good coat of tan’? and impress his fellow work- erson Monday morning. He gets the tan, but doesn’t appear Monday morning. He isin bed. The statistics of hours lost from work on account of sunburn, if such records were available, I am sure would be amazing. In fact, a tanned skin is no index to health. A bronzed skin may cover the most serious of body disorders. JULY and August are the dangerous months for sunburn, for then the sun delivers the most ultra-violet light, the areitle part of sunshine that burns the skin. Ultra-violet light, we recently have discovered, helps cure many ills. It is especially beneficial in treating skin dis- eases such as acne and eczema. But while it is good for us to be in the sunshine, out of doors, the danger lies in getting too large a dose of ultra-violet light in a single exposure. Sunburn is caused when ultra-violet light is stopped in the skin cells. The He Is Courting Trouble The office worker who goes to the beach for the week-end and sleeps on the sand in his bathing- suit is courting trouble. Monday is likely to find him in bed with a bad case of sunburn light causes a chemical change. A poison is manufactured that enters the blood, causing fever and headache. The chemi- cal burn kills the skin. Some of this dead skin bas to be absorbed by the blood, and this process adds to the poisoning. All this means extra work for the blood. Large supplies of blood rush to the burned surfaces with consequent disturbance of How to Avoid Sunburn 1. Protect yourself from direct rays of the sun in July and August. 2. Build up a coat of tan, if you can. This deposit of pigment will prevent the sun from burning your skin. 3. Acquire this tan gradually through short exposures. 4. If you havea skin that doesn’t tan, stop exposing yourself. For you, every new exposure means a new burn. 5. Wear a hat with a brim or carry a parasol. 6. Don’t go to sleep on the beach in direct sunlight. 7. Don’t go fishing or boating in the middle of the day in sun- shine. Reflected light from the water will burn you, even though you wear a hat. 8. Remember that a severe case of sunburn may have serious and lasting results. the circulatory system. This may be followed by congestion of the lungs and inflammation of the kidneys. The heat of sunshine haa nothing to do with the burning. You can prove this for yourself. Expose your arm to a 90-degree temperature before a fireplace or immerse it in hot water. The skin reddens, but the red- he ness disappears when the heat is removed. Expose your arm in direct sunlight of the same temperature for two or three hours and you will receive a burn lasting for days. Sometimes, not always, sun- Freckles The weather-beaten skin of Earl Sande, fa- mous American jockey, who rode Flying Ebony to victory in the last Kentucky Derby, is typical of the kind that freckles, instead of tans. In other words, the pigmentation or discoloration of his skin, instead of being distributed evenly, collects in small spots burn is followed by pigmentation—dis- coloration of the skin—the familiar “ coat of tan.”” Sometimes this pigment, instead of being distributed evenly, collects in spots that we call freckles. The pigment is manufactured in the deepest layer of skin cells. Under a microscope the pig- ment looks like tiny particles of brown paint. The more of these particles manu- factured, the darker the skin becomes. But perhaps you are one of those un- fortunate individuals who never tan. You suffer far worse from sunburn than your bronzed companion. Why? The latest experiments with ultra- violet light lead us to believe that the (Continued on page 113) iy if | j f y

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40 _ POPULAR SCIENCE MONTHLY August, 1925 ‘The Wonder City You . » Buildings Half-Mile High and 4-Deck Streets HE amazing pictures on _ these two pages were drawn from sug- gestions made by Harvey W. Cor- bett, president of the Architectural League of New York. They are a vivid, graphie expression of Mr. Corbett’s mental con- ception of the typical American city of the future—the place in which most of us will be living in a quarter ofa century or so. Unlike many other experts, Mr. Corbett ca nes does not believe that the future will bring —E the ‘‘decentralization” of our big cities. On the contrary, long study of modern The Architect and His Vision trends in architecture, city planning, and Harvey W. Corbett, noted American architect, at work on business and social life has convinced one of his models depicting his conception of the future city him that our cities will become more and more crowded. And, facing this contin- gency, he believes, we of this generation should begin now to plan buildings and highways with an eye on the problem of bandling people and traffic of the future. ieee streetcar and elevated railway, Mr. Corbett says, will disappear. Streets will consist of four or more levels, re- spectively for pedestrians, slow motor traffic, fast motor traffic, and electric trains, the uppermost level being raised above the present street level. Buildings will be half a mile high or more, containing offices and commercial establishments on the lower floors, and dwellings and amusement places on the upper. These latter will be reached by spiral escalators and will be supplied with pure air piped from the country. Though Mr. Corbett’s vision of the future city contains much imagination, it is in no sense fantastic. It is supplied by a practical man and a noted architect. His ideas are worthy of sober study. A picture of the present-day metropolis, with its skyscrapers and subways, would have seemed scarcely more remarkable 50 years ago than his conception of the future city seems today. Safe Highways—Elevated Parks Above is a conception of how highways from the city of the future will be arranged to pre- vent congestion. Notice how the cross high- way is elevated, with an ingenious system of curved ramps leading from one highway to the other. If you follow the arrows you will see how a car traveling in either direction on either road could pass readily to the intersect- ing highway without danger of accident. Mr. Corbett foresees future city parks raised to the level of elevated streets, as shown at right, with convenient auto parking space beneath 14; Ake Cir eT ! MALAY, i Wiig

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1925 ] tS hese sug- Cor- ague phie con- y of of us or SO. rbett pring ities. ydern , and inced 2 and ntin- ation s and m of iture. y, Mr. treets Is, Te- motor lectric raised igh or .ercial 3, and ym the ied by d with of the ‘ion, it ‘ied by hitect. ly. A ‘opolis, would irkable of the POPULAR SCIENCE MONTHLY August, 1925 May Live to Seey May Solve Congestion Problems bj VAAL H Hd | LIVING QUARTERS AND Hii {| PLAYGROUNDS so. Se y er ? ft) i . ( % Ris VY ail / : : 7 - A se - ayy ig d & A ie Ee 2 é 4 oF f AIRC inh phe" ii il = =o = Se ay! ( rere : ; : | . e | Wilt cr if Pv ES : % . 4 te a oe ae = TT ", | + items | 6 \ sem Sasa, “Ss ask =a 8 See Sade ETI | aren = Tene var fas “aie Sr ieee = | i ea j veri — } | LaF gaa as ee ake | aan ere | ¥ 9 all i ra a H Tide Wee ae = - 4 So \ | me iF tel ee afl) jf a SNS 7 id } ier oe ee » -, = a eee eae a ees - wisi = ~ a CES =i =] = a = Spa f, = eta es %, : See Sees = : 3 : oe i a 2 os go ee sa = = re exh ~*~ = cs a r ¥ oa F866 it os ae SR3 i » da 5 —_ ee oe ned a 1} Sa € > ae it 3 Fi SS Ss ah ‘ : 5 3 COLO ‘AURANTS aD me - ay } “ 4) +e : S: Yee g 1 s . * (ti Mat BAe: . . ry i , : ro “ : ‘ re Lak * PE MAA AN 4 ’ : oe, . ‘ m4 § AAG yt AN : - : % a id ‘. 4 y. ery “ ’ i ’ . ia ; ~ 5 4 . = . . * A { — . aN SL Y NY ~ ! 5 re . ih F : i a RAS be rhe . " l,j Ys a ash:). ES ! i 4 t ‘ " s : A : | , ae . : : ty il 6. — , 4 ? = a F ceenevens 5 i :! me RA, IEE ACTS a How You May Live and Travel in the City of 1950 i i : half a mile high will house offices, i Mr. Corbett, will be in four levels: The top blocks of terraced skyscrapers h e c i oli cetera of next lower level for slow motor traffic; the schools, homes, and playgrounds in successive po tae = roofs next for fast motor traffic, and the lowest for electric trains, Great will be aircraft landing-fields, according to the plan

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42 Semple Control for Plane. and Boat Perf ected Engine and Propeller Connection Shaft, housing and propellers of the Kersten mechanism. Propeller blades act with the rotor or independently By Arthur A. Stuart RULY revolutionary in principle is a new propeller for motor-boats and aircraft recently designed by Prof. F. K. Kersten of the Department of Electrical Engineering at the University of Washington, Seattle, Wash. The amazingly simple mechanism serves at once as propeller, rudder, and reverse gear. It is in the form of a rotor or disk, set in the bottom of a boat. A number of blades project from this disk into the water. They are driven by spiral bevel gears from the engine. The thrust upon the water is produced in two motions by these blades. First, the axes of the blades are caused to move in a circular path with a uniform motion, the plane of the path being at right angles to the blades’ axes. Second, while mov- ing in the circular path, the blades are made to rotate on their own axes, this motion also being uniform. ‘These two motions are so timed that each revolution made by all the blades around ee POPULAR SCIENCE MONTHLY August, 1925 Revolutionary New Propellers How Propeller Is Installed Illustrating the position of propeller on latest model streamlined motorboat. It is claimed by the inventor that need for rudder and reversing gear is eliminated by use of this invention banks inward; danger of capsizing is therefore eliminated. The makers claim that boat construction is considerably simplified and that, due to the center- board installation, which stabilizes the boat, the finest streamlines may be adopted. So impressed was the U. S. Govern- ment by the new propeller, that after repeated tests at Washington, D. C., it has ordered an installation of the aerial type to be made in the dirigible Shenan- doah, and the marine type placed in the ‘“‘admiral’s barge” of battleships. All the advantages claimed for the marine type of propeller, and even more, are claimed for Professor Kersten’s aerial model. Yet another new propeller, but of Boat Turns in Its Own Length The makers assert that aboat equipped with the propellers gives instant response to the wheel entirely different construction, is the in- vention of a Frenchman, Jean B. Icre. The Icre propeller consists of a vertical housing through the bottom of the hull, with a simple mechanism that operates six propeller blades around a horizontal circle, requiring only a one-way power plant to drive it. This means that all engine-reversing mechanism is eliminated. ‘TBE actuating mechanism is simply a cam at the end of the blade arm, following a circular guide within the housing. This guide causes a quarter- turn only of the blades from the horizontal to the vertical and return. Because of its construction, maneuver- ing, such as is required of destroyer fleets, is said to be possible to a phenomenal degree. It is claimed that in tests conducted ina 40-foot vessel with engine running a cor- responding number of revolutions, the Icre propeller covered a given course in from six to 12 per cent less time the circular path also makes one- half a revolution of each blade on its own axis. The consequent thrust given by the combined movement is controlled at will by a simple device incorporated in the propeller. HE propeller blades revolve not only on the rotor’s mo- tion, but also independently of it. It is claimed that any boat equipped with the new propeller can navigate safely without re- verse gear or rudder. The boat can be turned almost in her own length, so quickly will she respond to the action of the new installa- tion. Again, it is said that even when going at full speed, a boat can be stopped in two lengths. than that required for a screw propeller. The basic principles of M. Icre’s propeller have many applications. —as for outboard motors, certain phases of dirigible control, and for deep-draft vessels, shallow-draft vessels, and particularly for tow- ing craft. Tailless Biplane Tested | egy etl recent trial flights near Santa Monica, Calif., a tailless biplane weighing less than 500 pounds was declared practical by Prof. A. A. Merrill of the Cal- ifornia Institute of Technology. Such a machine in miniature, shot from a catapult, sailed more All movements are governed by the way the propeller blades are manipulated. In turning, a boat of the boat’s hull. blades on a horizontal circle. No Rudder nor Reversing Gear Needed The Icre propeller has a vertical housing through the bottom A simple mechanism operates six propeller Reversing gear is eliminated than 100 feet and maintained a speed of 35 miles an hour. It was held perfectly balanced in the air by currents from fourlargemotors. |

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St, 1925 rs , in Its sth ssert that i with the Ss instant che wheel the in- B. Icre. vertical he hull, operates rizontal y power that all ninated. simply a de arm, hin the quarter- srizontal aneuver- er fleets, nomenal cted ina 1g a cor- ons, the -ourse in less time a screw M. Icre’s lications. 3, certain |, and for low-draft for tow- Tested ial flights Calif., a less than practical f the Cal- nology. niniature, iled more ntained a ir. It was in the air gemotors. August, 1925 Where nightsticks are ¢ useless and shooting (3. uncalled for, police- men now are using ‘the billy, shown be- low. It will project * a stream of blinding se j mustard-camphor li- oo quid 30 feet ; ODERN warfare methods are being adapted for use POPULAR SCIENCE MONTHLY “ ; Tear-Gas Bombs Rout Mob > | by police departments in several large cities in the United States. Tear-gas bombs, grenades, maces, and billys are used for attack and defense. A gas mace or billy, it is claimed, will enable a single officer to accomplish more than 20 men equipped with the old type of night-stick. The mace shoots out a volume of gas, enough to fill an ordinary room. The grenades are said to be particularly effective for breaking up mobs and riots and driving barricaded criminals from retreats. Huge crowds can be set to weeping instantly, so that not one of their number can see, and no mob will continue once blinded with irritating tears. Smarting of the eyes and tears con- tinue for from two to five minutes after exposure to the gas. The exposure is harmless, since the gas has no permanent injurious effect. The mace has the same size, shape, and weight as a standard police night-stick. When pointed at a man or group of men and a button pushed, a cloud of tear gas is projected from the end for a distance of from 20 to 30 feet. The charge is much like a shotgun shell and can be installed easily. The billy is like the mace, except that the barrei is shorter. One hand grenade, it is claimea, will 43 Using Gas for Self-Defense Above: Officers demonstrating how a bank messenger can shoot gas at would-be hold-up man, rendering him helpless and unable to resist arrest. Center: Soldiers instructing San Francisco policemen how to shoot tear bombs from a rifle. Some of the police students shown in the illustration are carrying gas masks, which they must learn how to use stop a mob of hundreds in an 80-foot street. Thrown into a large hall, a tear grenade will cause every occupant to retire hastily. The grenades do not explode, are weather-proof, and are provided with a safety device so that they can be stored indefinitely. Rifle grenades are built on the same lines as hand grenades, but these can be fired from a rifle with blank car- tridges. These weaoons are used when greater range is desired by the men who are using them. At army posts soldiers are acting as instructors to policemen, showing them how to handle the new tear-gas equip- ment. Ten- Year-Old Boy Is Hero of African Hunting Expedition party sailed from New York for Nairobi, British East Africa. It consisted of Mr. and Mrs. E. L. King, of Winona, Minn., and their 10-year-old son, Ernest. Accompanying them was an official photographer, a motion-picture cameraman, and an expert taxidermist from New York’s Museum of Natural History. Mr. King also had been com- missioned by the University of Minnesota to get specimens of big game. Escorted by a safari of 75 natives, the party entered the jungles of Africa. Though it was their first experience with the big game of the dark continent, they were by no means amateurs, having hunted in South America, Canada, Alaska, Florida, and China. Mr. King is a well known marksman, and Mrs. King was at one time world’s champion clay-target shot, and twice champion of the Northwest, while their son has handled a rifle since he was six. Or: day last winter an interesting After about four months in the wilds, the Kings returned home, with Ernest, Junior, the hero of the expedition. Un- aided, he had shot and killed a huge rhinoceros with his 30-30 rifle. Mrs. King killed several lions, and 400 cases of specimens were sent to Minnesota and to New York’s Museum of Natural History. Intrepid Young Sportsman Ernest King, Jr., 10-year- old big-game hunter, be- side the rhinoceros that he killed single-handed in the wilds of British East Africa, where he spent a holiday with his parents

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44 HA VE You Met the Crafty Doodle- bug, or the Ants that KeepCows? f ,t4 re ‘4 4, mae? ° . * wa POPULAR SCIENCE MONTHLY August, 1925 Courtesy Educational Film Ex- change, Inc. Nature’s Craftiest Hunter A ferocious doodlebug or ant-lion is seen above devouring an ant it has captured in its powerful jaws. At the left the same ugly insect is pre- paring to dig the pit for his victims There Are A Thousand Different | Insects in Your Back Yard Amazing Stories from a Near-By World of Bugs and Flies NE afternoon, not long ago, Dr. O Frank E. Lutz was showing a friend the back yard of his subur- ban home in Ramsey, N. J. The two men were examining a peculiar-looking in- sect on a rosebush. In the course of a conversation about insects Doctor Lutz remarked, ‘“‘Every year there are at least 500 species of insects in my back yard.” The friend expressed surprise and skepticism, and Doctor Lutz determined to prove it. Today in the American Museum of Natural History in New York City, where Doctor Lutz is Curator of the Department of Entomology, there is a collection of 836 species of insects that were caught in that one New Jersey back yard. And the collection is incomplete. When all of the specimens are mounted and labeled, Doctor Lutz expects the exhibits to amount to well over a thou- sand. One thousand different species taken from a plot 75 by 200 feet! All of us who have a back yard are probably boarding as many va- rieties of guests—perhaps more, for the garden in this case is in no way unusual. It is in the middle of a village of about 2000 popula- tion. Part of it is planted in vegetables, part in flowers, and part is lawn. The surprising collection more- over, was made casually, during twosummers. The insects were caught while Doctor Lutz was strolling in his garden, or when the electric porch light attracted swarms of them, on summer evenings. In all but one of 23 general classifications into which all in- By G. B. Seybold house or yard, and Doctor Lutz says that you can find fully as many in your own garden, if you will look for them. Sorting your principal insect visitors Here is the friendly lady-beetle dining on destructive plant lice or aphids. These lice have now become the servile ‘‘cows”’ of ants into groups easily remembered, you have (1) true flies—those that have no more than two wings—such as mosquitoes; (2) butterflies and moths (scaly-winged insects); (8) beetles; (4) wasps, bees, and ants; (5) true bugs, such as the squash bug, which have sucking mouth parts, and (6) grasshoppers. er what about spiders? With that question you disclose a slight ac- quaintance with insects, for a spider is no more an insect than a crab is. For one reason it has too many legs—two too many, to be exact. Only six-legged crea- tures come under the classification of in- sects, and a spider has four pairs. The insects in your back yard help © themselves to the foliage of your fruit © trees, bushes, vegetables, grass roots, and © Every plant in the garden © furnishes refreshment for at least one” plant stems. species of insect. Some insects, such as” the roach, prefer cooked foods. ever man likes is good enough: steal when he crossed the seas. The most numerous of your back-yard guests are aphids, or plant lice. would bring starvation to all of that these two classes have sects are divided, representa- vives were found, either in the Corner of Doctor Lutz’s back yard at Ramsey, N. J., where he found at least a thousand different species of insects joined forces. The lice are the ants’ “‘ cows.” They excrete a sweetish sub- What- © for him, so he sticks close to” kitchens, where he manages to™ a bit now and then.’ Roaches have tagged man about: the world for thousands of years, | even following him on _ ships” If left to grow un- | molested, the hordes of these ¥ us, by destroying all vegetation. — | Next in number in the garden 7 are ants, and a distressing fact is ~

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gust, 1925 lunter 't-lion is it it has ws. At t is pre- victims rd you have no more Squitoes; ly-winged bees, and 1e squash th parts, Vith that light ac- ider is no For one —two too reed crea- ion of in- 3. ard help © our fruit © oots, and © 1e garden - least one = ; of your # phids, or ¥ gTOW un- | of these ¥ to all of -getation. 7 e garden — ing fact is 7 ses have , *6 cows.” tish sub- August, 1925 POPULAR SCIENCE MONTHLY 45 tance called “honey-dew,” which is very much liked by certain species of ants. These ants work hard to care for their tiny “cows.” NE species of ant, the Lasius niger, exercises particular protection over the eorn-root aphid. During the winter this ant stores the small black eggs of the lice in its nest, moving them around as the weather changes, to keep them dry. When the eggs begin to hatch in early spring, the ants uncover the roots of smartweed and other plants and put the cows out to pasture. a farmer has at length put in his corn crop, the ants make a last transfer and transport the lice to the corn roots. Fortunately for us, lice have enemies as well as friends in the insect world. One of these is the lady- peetle. All of us know the little rhyme warning the lady- bird to fly away home to save her children from destruction | from fire. Doctor Lutz ex- Cc. plains that the rhyme origi- nated in Europe, where hop vines are burned after the harvest. These vines are usually full of the young of lady- beetles dining on plant lice. The name “lady-beetle’ dates from the Middle Ages when these insects were dedicated to the Virgin and called the ‘‘ Beetles of Our Lady.” panying article. these wonders. Opens World’s First Insect Zoo Then, when the T HE most amazing zoo in the world—a 40-acre menagerie of insect life—has just been opened to the public in the Interstate Park near Tuxedo, N. Y. the idea of Dr. Frank E. Lutz, Curator of Entomology of the American Museum of Natural History, who is shown in the photograph. Doctor Lutz’s fascinating observations of the thousand insects in his own back yard are described in the accom- Now, under his direction, the American Museum is giving the public a chance to view and study Visitors at the zoo will learn of Nature’s useful jobs for her bugs, beetles, bees, and flies. Doctor Lutz has estimated that this remarkable zoo will contain at least 5000 kinds of insects. 7 the best ways to control in- sect pests, entomologists ad- vise, ig to stir up warfare. Increase the number of the pest’s enemies and let them fight it out, cheering from the side lines. Craftiest of all garden in- sects is the ferocious-looking doodlebug or ant-lion which develops into the marsh fly, resembling the slender-bodied dragon-fly but with more delicate wings. Bright lights have a fatal attraction for it, so you may make its ac- quaintance some night when you have forgotten to mend the hole in your window- screen. The doodlebug larva makes a pit in loose gravel the shape of an inverted cone and hides at the bottom with just its powerful jaws protruding, ready to seize its prey. An ant or other insect tumbles into the trap, assisted in its fall by showers of sand thrown up by the lion. Once in the pit, the victim’s fate is sealed. | Few insects are injurious in aaa all stages of their life. In fact, as arule, it is only the grub or caterpillar that does the damage. Some insects are often easy to see and It is wexg Gestroy in one stage or another. The Horticulturists in California, realizing @® the good these beetles do, often scoop up big masses of the adults from the piles in which they congregate for the winter, and put tons of them in cold storage. They distribute them in the season when plant lice should be controlled. Another enemy of plant lice often seen flying about electric porch lights in evenings, is the aphis-lion. This is a rather large but delicately formed crea- The Camping-Ground of Pests A colony of tent caterpillars in the forks of a tree. When these pests are gathered in their tent it is possible to destroy them easily Two Interesting Creatures The upper picture shows a dragon-fly, or darning-needle, eating an insect while in flight. This vicious-looking but harmless fly swoops down and scoops up its prey in its basket-like legs. Below is the aphis-lion, a voracious enemy of plant lice. Doctor Lutz tried to count how many lice one of these could devour in one meal, and gave it up ture with light green, lacy wings. Its young are so voracious that if it laid all of its eggs in a mass, the first one hatched would eat all of the rest. So the mother spins stalks of stiff silk and sticks one egg on the end of each stalk. Thus all are given an equal chance. Doctor Lutz, curious to know just how many plant lice one aphis-lion could con- sume at a single meal, tried to keep count one Sunday afternoon. He got tired counting, he says, and turned the insect loose on the honeysuckle vine to keep on with the good work. Doctor Lutz goes out into the fields, gathers aphis-lions and One of turns them loose in his garden. eggs of the tent caterpillar, for example, are deposited in bands, 300 or 400 toa band, encircling a small twig of some tree, preferably an apple or wild cherry. These bands are rounded at the ends and covered with a protective ‘‘varnish.” In the winter, when there are no leaves to hide them from view, they can be detected easily and destroyed. ‘TENt caterpillars have an interesting colony life. When the eggs hatch, all the caterpillars join in spinning a temporary silken tent around what is left of the egg mass. From here they go out (Continued on page 115) ee ae A Battle in the Flowers One of many thrilling battles of the insect world. This remarkable photograph shows a hornet swooping down to attack a bee

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46 Would You These Daredevils Florida’s Human Torch Providing thousands of spectators with thrills and chills, Daredevil Wilson daily climbs this ladder, saturates himself with gasoline, sets fire to his clothing, and plunges from the dizzy height of 125 feet into the water-tank below oo Fé If He Should Let Go Charles N. Fitzgerald is a past master at performing hair-rais- ing stunts on the outskirts of an airplane, thousands of feet above the earth. He climbs from the fuselage, steps lightly out on a wing, and dangles in midair, supported only by a wire strut POPULAR SCIENCE MONTHLY Like Their Job? Defy Death for a Living August, 1925 Try This on Your Motorcycle Motorcycle rodeos furnish a constant supply of hairbreadth escapes from injury or death, Albert Milner, champion trick motorcyclist, is pictured above, doing a very difficult stunt } | * Above: Benny Fox calls himself the ‘human fly” and he is shown performing on a rope high above Chicago’s streets. At left: Carl Anthony, of Oak- land Calif., has climbed to the top of the flagpole of the Oakland Tribune, some 300 feet above the sidewalk, and is doing hazardous stunts on the apex of the slender shaft, nonchalantly sup- porting himself on one hand, and meantime keep- ing his balance with an umbrella, closed, at that Suspended between Earth and Sky Aug) for his nou bef sha pro fus pla pel! alt of the in a ODM & ct @O wt pr

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August, 195 cycle at supply or death, ‘cyclist, is ult stunt nd Sky man fly” gh above 7, of Oak- e flagpole et above stunts on ntly sup- ime keep- i, at that August, 1925 Pilot Controls His S acoustic speed indicator for air- planes, which makes it possible for a pilot actually to hear the speed of his machine in flight, recently was an- nounced by M. de Gramont de Guiche, pefore the French Academy of Science. The invention is a small torpedo- shaped instrument, with a two-bladed propeller at its nose, attached under the fuselage. Air pressure set up by the plane’s forward motion drives the pro- peller, which, in turn, drives a small alternating-current generator. The speed of rotation, of course, depends on the speed of the airplane. The propeller shaft is placed between the arms of a fixed U magnet, which end in ring-shaped pole plates. Between T= perfection of a remarkable POPULAR SCIENCE MONTHLY 47 SPEED INDICATOR peed by Sound these plates the wire-wound spool of the generator is mounted around the shaft, without touching it. Between the end plates of the fixed spool and the armature rings of the magnet poles, circular disks are keyed to the shaft. Each disk has eight teeth, corresponding with the same number of teeth in the armature rings. As the propeller shaft revolves, an al- ternating current is generated. This reaches its maximum every time the teeth of the disks are alined with the teeth of The picture above shows the location of the wind- driven acoustic speed indicator under the fuselage. At the left is a broken-away view of the torpedo- shaped instrument, showing design of the alternating- current generator that produces a humming sound in an earpiece worn by the pilot. pitch of this sound. the pilot, with a little practice, is able to judge accurately the speed of his plane How the Sound-Maker Operates By variations in the the armature rings. Thus each full revolu- tion produces eight maximum impulses that are transmitted to an earpiece worn by the pilot, creating a humming sound, which varies in pitch with the speed of the plane. A “Second Wind” for Airplanes Six Miles Up hours is one of the possibilities held forth by Louis Damblanc, as a result of his invention enabling airplanes to fly swiftly at high altitudes. By a simple apparatus built into the engine, this French engineer claims to have mastered the upper atmosphere in a way never before approached. Under present conditions an engine loses half its power at an altitude of 34% miles. With the Damblanc attachment it is declared the loss will be reduced to little or nothing, even at a height of six miles. The French Air Service has super- vised successful tests of the apparatus, the importance of which is indicated by the fact that it was laid before the French Academy of Sciences by Presi- dent Paul-Prudent Painlévé, of France. In upper altitudes the speed possibilities are vastly greater because of lessened atmospheric resistance. With existing equipment, however, the loss of engine power has made it impossible for aviators to take advantage of this. To overcome this difficulty by increas- ing compression in the cylinders, Dam- blanc has modified engine construction to enable the pilot, at will, to change the length of the connecting rods that move the pistons in the cylinders, and so vary the space in the compression chambers. F toss New York to Paris in a few The secret of the device lies in an eccentric crank-pin arrange- ment. When the eccentric is set at the point (shown at Y in the theoretical diagram) the compres- sion space is reduced and the motor will function at high alti- tudes. When the eccentric is in the other position of minimum elongation (shown in X) the piston does not go as far into the cylin- der. This enlarges compression space, andso lowers compression to the proper point for running at ground level. COMPRESSION = SPACE ing a ADJUSTING ECCENTRIC CRANK SHAFT The Power Booster Above is an airplane motor equipped with the new power-increasing device. Arrow A points to the housing of the device; arrow B points to the adjusting lever. The diagram shows the eccentric crank-pin arrangement by which compression space in the engine cylinders is reduced at higher altitudes. X shows position for running at ground level, and Y for high altitudes, changed at will by the pilot

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Dangers in Bolting Your Food The Month’s News of Useful Discoveries and Inventions Told in Easy-to-Read Words New Engine for Transatlantic Flight Rene Fonck, French ace of aces during the war, is shown here with the new airplane engine he has designed especially for transatlantic flight. This motor has run on the block at full speed for 120 hours continuously and-cents value of keeping well in- formed? Are you moving ahead with the world’s advance, or are you let- ting yourself slip backward? It is to help you keep pace with the progress of events that POPULAR SCIENCE MONTHLY presents here, in brief, understandable form, the month’s outstanding achievements in invention and scientific discovery. 1y YOU know the practical, dollars- FROLTING your food is extremely dan- gerous, for this common habit largely is responsible for the increase of cancer in the United States, Dr. J. D. Osmond, of Cleveland, Ohio, explained recently be- fore the Radiological Society of North America. When a man under nervous strain, he said, swaflows his food in chunks, it tends to be retained in the gullet instead of going on to the stomach. This irritates the gullet and frequently causes cancer. Scientists throughout the world are paying an increased amount of attention to the rapidly spreading plague. Sir William A. Lane, a noted English surgeon, blames the unnatural habits and diet of civilization for cancer. The body is poisoned slowly, he says, because the residue of digested food remains in the body longer than it should and stagnation sets up local irritation. This could be prevented, he adds, if we would eat rough foods as our uncivilized ancestors did, instead of prepared foods, highly cooked, milled and refined. The cause of every case of cancer he has ever had the chance to verify, he asserts, has been chronic constipation. New York City is to be the first muni- cipality in the world to erect a cancer institute of its own. Sufferers from can- cer will have free treatment by the latest radiographic apparatus and a 200,000- POPULAR SCIENCE MONTHLY volt X-ray machine. The latter will be housed in an iso- lated one-story building, having thick walls lined with lead, so that the powerful charge of electricity can be used with safety. It is amazing that in spite of these tremendous efforts to conquer cancer, it should still re- main one of the most dreaded dis- eases known to man. A New Grain D ON’T worry about the world starving to death. You have heard it said, per- haps, that the corn and wheat areas of the earth now are cultivated to the limit, and that some day the increasing pop- ulation will not have enough bread. Be cheered by the news that P. J. Wester, a scientist of the Philippine Board of Agriculture, has dis- covered remarkable possibilities in adlay, a grain grown in the trop- ics. He says it will take the place of either wheat or corn, if need be. We are acquainted with one of its near relatives—Job’s tears, hard seeds used often + for ornamental beads. The adlay has a softer shell than these. Na- tives in the tropics have used the seeds for gen- erations for ornamental purposes, but not for food, becausethey could not be hulled easily by primitive methods. One great advantage is that thesame machin- ery used to mill wheat can be used for the new grain. Experiments have shown that the best bread is made by mixing it with wheat flour in the proportion ° of one-third to one-half adlay. When more than two-thirdsadlay is used, the bread becomes heavy. Cracked adlay At Work to Purify Our Rivers Miss Louise E. McGrath, C.E., who holds the distinction of being the only woman chemical engineer in the United States, is at work with Uncle Sam to prevent the pollution of streams. operating an apparatus that purifies water used in factories August, 1925 makes a very acceptable breakfast food, The plant is a kind of coarse grag growing seven or eight feet high, with long leaves similar to those of corn. The grain is inclosed in a soft shell. It has an amaz. ing yield—an average of 2550 pounds to the acre. Spider Webs as Fish Nets I* YOU lived in a tropical country yoy might become lazy, too, and use your wits only to figure out some way to get work done for you. Natives of Australia and the South Sea Islands induce spiders to furnish them with fish nets. The webs are spun by large spiders with bodies about two inches long, and are extraordinarily tough and durable. Ne- tives bend a strong twig into a hoop, take it into the woods and wave it among spider webs spun between branches until the hoop is covered with meshes. Fish become entangled in the tough web when it is immersed in a stream, and are caught easily. Natives of New Guinea bend a piece of bamboo into the shape of a big tennis racket. They place this upon a bush and Here she is,

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od eful 10ns§ ords ‘Kfast food, OATSe grass h, with long The grain aS an amaz- pounds to Nets ountry you d use your way to get f Australia uce spiders piders with g, and are ‘able. Na- hoop, take it among nches until shes. Fish 1 web when are caught 1 a piece of big tennis a bush and . of being s at work ere she is, factories August, 1925 POPULAR SCIENCE MONTHLY 49 spiders obligingly weave a strong web upon it. Fish up to a pound in weight can be caught in such a net. Daring Adventures E world is full of ad- venture for the man who seeks it. Into the midst of tribes of savage Amazonian head-hunters who greet visi- tors with poisoned arrows, an expedition led by Dr. William McGovern is pene- trating this summer. The explorers will study the mysterious customs to be found in South American country between the Andes and the Amazon valley. Little is known about the savages here, except that they keep pigmy slaves and shrink the heads of victims, Cables Tested in a **Chemical Ocean”’ Crowding 3000 miles into 24 in- ches for the study of transoceanic cable transmission has been ac- complished through a remark- able “chemical ocean” of a few quarts recently perfected in the electrical research laboratories of the Massachusetts Institute of Technology. The apparatus, consisting of a glass container in which aluminum plates are sus- pended in solution, makes it pos- sible to duplicate actual trans- mission conditions existing in cables on the bed of the ocean by a secret process, to the size of an apple. The ex- plorers expect to impress the natives with jazz records and radio. Doctor McGovern was the daring adventurer who, dis- guised as a servant, got into Lhasa, the forbidden city of Tibet, about two years ago. In Baku, Azerbaijan, on the shores of the Caspian Sea, another party of adven- turers is digging for the treasure of Alex- ander the Great. A romantic feature is that the archeologists are following direc- tions in an ancient map said to have been stolen from a Turkish sultan many years ago. Legend declares that this map shows the exact spot where the riches are buried. At home, one of the most ambitious feats of American mountaineering is being Odd Snakes from Africa Arrive at Zoo Officials and keepers at the Bronx Zoo, New York, had an exciting five hours recently when a large shipment of snakes, including deadly black cobras, mambas, and pythons, arrived from West Africa. Doctor Raymond Ditmars, curator of reptiles at the zoo, is shown, here with a group of harmless ball pythons. When frightened, these snakes roll themselves up in a ball for protection from intrusion He Photographs Interior of Rifle Barrel , By means of a remarkable periscopic camera invented by Dr. I. O. Gardner and F. A. Case, it now is possible to photograph the interior of either a rifle or a cannon barrel undertaken by 11 men, all amateur climbers, who are attempting the aseent of Mount Logan, the highest mountain in Canada. It is 19,850 feet high, second only to Mount McKinley in North Amer- ica, and has never been scaled. It is approached from Alaska over a perilous route mapped out by Captain Albert H. MacCarthy of New Jersey. The expedition is under the auspices of the Alpine Club of Canada, but it in- cludes five climbers from the United States. The summit of the peak is 11,000 feet above the highest available base site, and there is great danger from avalanches. Achievements in Flying Misco planes designed to fly 300 miles an hour are being built for the United States Army and Navy for entrance in the Pulitzer Trophy Race this fall. With these it is expected that the United States will recover the world’s speed record from France, which now holds it at 278 miles. A new world rec- ord for non-stop flights was made re- cently by the PN-9, _an all-metal naval plane, which flew 28 hours and 36 minutes without stopping. It came down only because its supply of gasoline was ex- hausted. It carried 1450 gallons. The test was made to see whether the plane could hop from California to Hono- lulu successfully. From the speed main- tained in the trial it was estimated that the plane would have flown just far enough to have covered this distance. Our Mentality Exposed Mest we admit that we are stupid? A group of University of California scientists, after many years of study, have decided that the human race has made no mental progress in 3000 years. They have concluded that we know about as much today as the people who lived in Babylon, and not as much as the Greeks did 2000 years ago. Doctor Robert Millikan discovered that by merely substituting familiar names of persons and places for unfamiliar ones in writings of the ancients, these writings could not be distinguished from the modern. And people are still shamefully super- ’ gtitious, it was found. One test showed that of 977 California teachers 875 be- lieved seriously in black cats and dropping spoons as omens. Criminals as a class are as intelligent or more so, than the rest of the world, (Continued on page 114)

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POPULAR SCIENCE MONTHLY August, 1935 French Mountain-Climber Designed to haul heavy passenger trains at high speed over steep grades between Paris and Marseilles, France, this new streamlined locomotive is said to be the most powerful in Europe. It develops as much as 2500 horsepower —and Still Runs Nearly 100 years ago President Andrew Jackson adjourned a Cabinet meeting to see the Atlantic, the first locomotive that ever puffed into Washing- ton, D. C. Today this old- timer (above) is still able to run under its own steam. It was built by Phineas Davis of York, Pa. The Old and New in Engines Remarkable Advances in Locomotive Design Runs by Batteries Storage batteries supply the driving power for the Baden (at right), a new type of Diesel electric locomotive developed in Germany. It is said to have tremendous pulling power Trackless Train What is declared to be the world’s first trackless train (left) recently completed a run from New York to Los Angles, Calif. Loco- motive and_ sleeping-car roll on automobile wheels © K.&H. Railroad ‘‘Camel’’ In recent tests on the Swedish state railways be- tween Stockholm and Gothenburg, a new type locomotive called the Camel (right) is said to have consumed less than one-twentieth as much water and 40 per cent less fuel than used by the ordi- nary locomotive. It hasa special condensation ap- paratus invented by Fred- rik Ljungstrom, a _ well known Swedish engineer

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gust, 1935 ~W dl » ‘4 InN > the ‘Tain eda r to OCO- Car 1eels August, 1925 POPULAR SCIENCE MONTHLY 51 Oddities of Motordom 4 Ingenious Creations in Gasoline Cars : Da a ee ares a 3 | es ee An Automobile for $3.50 An old motor once attached to a bicy- cle, a piece of water-pipe, an old fire- extinguisher, and four small wheels are parts of this remarkable car built for $3.50 by Howard Schulenberg, a young man who hails from Portland, Orez. Cycle Sedan A Roman _=§sportswo- man, a motor enthusi- ast, saw no reason why cyclists should not have as much protection as occupants of a cloced car. So she designed this ingenious tcp “hat covers both the motor- cycle and its sidecar New Mail-Car A three-wheeled mail- delivery car of motor- cycle type (left) re- cently was adopted by the German Postal Service. It hauls a small two-wheeled trailer for carrying heavy mail-sacks Novel Freight Taxi Appears in Paris This light and speedy freight taxi is a recent innovation in Paris, France. It delivers packages and bundles for anybody, anywhere in the city. Delivery charges are determined according to the mileage readings on a meter Midget Motorcycle The little fellow must have one like dad’s. This time a German manu- facturer has made for him the small- est motorcycle. It weighs only 30 pounds, yet is equipped with every- thing that goes on a full size machine Gasoline-Driven Streetcar Aremarkable gasoline-driven streetcar (at the left) recently was put in oper- ation in New York City. While it carries its own passengers, it also ae ae serves if it is mecessary as a power pie TN : ett eke car for the ordinary streetcar trailer

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52 Now Patients Drink Sunlight to Cure Disease Y MEANS of a new ultra- violet-light machine the curative powers of sunlight can be administered internally. Sunlight long has been used in the treatment of numerous diseases—in fact,it is one of the oldest and most effective medi- cines, but to a great extent its use has been limited to certain diseases. The scope of this natural curative power, through the use of this ultra-violet-light machine, it is claimed, will be enlarged greatly. Used in the mouth and throat, it is reported to have proved beneficial in cases of several diseases. The machine was shown recently at a nursing. exhibition in London, where it drew much attention and favorable comment. Fuel-Saving Smoke-Consumer Made of Scrap Iron y . ghd plan or device to keep the air of cities fresh and clean in this day of manufacturing and industry seems cer- tain to have an immediate value. Engi- neer Fred Kammer, of Cincinnati, has contributed to modern invention a smoke- consumer designed to serve also as a fuel- saver. The device is constructed of scrap iron and, as the idea is carried out in a Cin- cinnati plant, consists of a system by which preheated air, admitted over the fires in the boilers, is said to bring about perfect combustion. Since their installa- tion several months ago, the smoke- consumers are reported to have saved about 40 tons of fuel for the plant. The picture shows Engineer Kammer standing beside a boiler equipped with one of his fuel-saving smoke-consumers. Cork Houses in England OMPRESSED cork, covered with 11% inches of concrete, is being used in the building of houses at Deal, England. It is said to be fireproof and sound- proof. POPULAR SCIENCE MONTHLY How ultra-violet light is administered internally with the new machine Lightning-Rods for Trees O SUBJECT are trees to being struck by lightning that the rodding of valu- able trees to protect them from possible destruction is advised by tree experts of the Department of Agriculture. Studies in various localities have shown that the oak is struck by lightning more often than other tree. The elm, ash and poplar also are susceptible. **“Radium Chain’’ for Cancer N ASTONISHING new treatment for cancer by ‘‘radium chain” re- cently was described by Dr. Sidney Yankhauer of New York City. The chain he said, is made of three platinum links, with capsules containing radium eman- ations. These are incased in rubber and weighted with a gold ball. The chain is swallowed by the patient and kept in the intestines several hours a day. August, 1925 Simple Window Support Does Away with Sash Cords A NEW device for support- ing windows in any posi- tion, without the use of sash cords, weights, or pulleys, ac. complishes its purpose through a roller and a_ supporting bracket made of spring brags. The bracket is attached to the sash and carries the roller horizontally when the sash js being raised. One end of the roller is confined, while the other has a slight play, allow- ing it to assume a slanting po- sition from the force of gravity on the sash. The resulting friction, it is claimed, is suffi- cient to hold the sash in place, but yields readily when the window is pulled down. The spring construction prevents rat- tles and holds the sash tight. Two of the supporters are used on each side of a sash weighing not more than 15 pounds. For heav- ier windows more of the supporters are used. The de- vice is said to be less expensive to install than are the usual weights. A RIFLE the size of a light machine- gun that will shoot bombs a distance of two miles is re- ported to have been invented by R. Okamoto, a Jap- anese engineer. Section view of sash, showing supporter Roofing Plant Carried on a Small Truck A ROOFING company of Reading, Pa., instead of using scrap wood as fuel for melting the pitch used in roofing, as most roofers do, has constructed on the rear of a Ford chassis a modern oil-burn- ing heater. The lump pitch is put in through a door at the top of the heater and the melted pitch is drawn off at the bottom by means of a large spigot. An oil-burner somewhat similar to those used in oil-burning house furnaces fits in the bottom of the heater. A 60-gallon tank, placed behind the seat of the car supplies the fuel oil. By means of a small hand pump on the dashboard, 30 pounds air pressure is maintained in the tank. Pumping is required only once an hour during the operation of the heater. Labor costs are said to be reduced con- siderably by the oil-burning heater, and the burner is compact, easy to operate and clean. GPR AE : COATING & RO OF EMS " gOoF REPAIING An oil-burning heater, mounted on a small truck, heats the pitch for roofing

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ust, 1925: Does 1s upport- 1Y Pposi- of sash leys, ac- through porting gz brass. ched to le roller sash ig l of the tile the ’, allow- ting po- gravity esulting is suffi- n place, 1en the nts rat- Two of ch side chan 15 f sash, porter ok 0-gallon the car a small pounds e tank. an hour 2ed con- er, and operate August, 1925 Portable Steam Radiator Heated by Electricity N ELECTRIC steam radiator is one of the la- test developments in modern heating for the home. The heating element ex- tends throughout the radiator ina protective seamless brass tube, which assures an even heat in every column and pro- vides a large radiating surface for heating the water sur- oa rounding it. Water is supplied through a filler cup in sufficient quan- tity to cover the heating ele- ment and current is applied by turning the switch to “‘High” for bringing the water to the steaming point, after which it can be turned to “‘ Medium” or “‘ Low.” POPULAR SCIENCE MONTHLY Radiator can be used near any switch 53" ‘‘Daylight’’ Spectacles Invented for Eos, Matching Materials and Dyes _ *S JO LONGER need a sales- man take material to the window to show a prospective customer the effect in day- light; nor need he even turn on aspecial light. Instead, he soon will be able to hand the customer a pair of daylight spectacles, invented by Dr. Hermann Weiss of Vienna. Already the spectacles have come into wide use in labora- tories in the textile, paper, and dye industries. These daylight spectacles are of blue glass that absorbs some of the yellow rays in which the ordinary incan- descent lamp is rich, but that are not present in such abundance in sunlight. Safety Butt-Hook for Logs Prevents Accidents EVERE accidents sometimes occur in lumbering camps when logs dragged up steep hillsides become unhooked ac- cidentally from the lines pulling them. Too, recovering the log means great loss of time. A safety butt-hook recently invented prevents this accidental unhooking. Press- ing a thumb latch opens a plunger suf- ficiently to allow the line passing around a log to be placed within the hook. The plunger then drops back toa closed position and the hook is locked automatically by a spring that forces the latch back to its original position. Have you entered our remarkable $10,000 Contest? See page 29 of this issue of PoPULAR SCIENCE MONTHLY Improved Metal-Cutting Tool NEW tool that cuts metal at higher speeds and in larger chips than practicable with standard tools was de- scribed to the American Society of Me- chanical Engineers by its inventor, Dr. Hans Klopstock of Berlin, Germany. Tests made in foreign railroad shops, Doctor Klopstock claimed, indicate that production can be increased about 30 per cent by the new too Man Builds Sun Parlor for His Chickens ORDER to take full advantage of ultra-violet light, which experiments have shown to have a decided beneficial effect on egg production, H. D. Goodale, of Williamstown, Mass., has constructed for his chickens a unique sun porch. A glass roof travels smoothly on a track and when the sun shines, the roof is slid out so that the hens can get the full benefit of the ultra-violet or health-giving rays of sunshine. When it is cloudy or raining, the glass roof is used for protection from the weather, and mercury-arc electric-Jight lamps are used to provide the hens with artificial sunshine. How the sun-porch extension is built on an ordinary chicken-house Shoemaker’s Last Distributes Hammer Blows Evenly HE shoemaker’s last shown above is intended especially for the father of a large family who finds that the only way to keep his children well shod is to mend their shoes himself; but a profes- sional shoe-mender, too, will find that it has its advantages. It consists of two parts—the last itself over which the shoe is placed, and the support, with its wide, curved base that fits comfortably over the shoe-mender’s knee and, by reason of its size and shape, distributes the shock of the hammer blows so that they cause no discomfort to the operator. One other improvement is the insertion of a rubber disk between the last and its base. New Railroad-Crossing Guard SWEDISH engineer, A. Westfelt, ‘ recently invented a safeguard for railroad crossings. It consists of a bar, seven feet high, that swings out whenever a train approaches and short chains that strike any car passing underneath. The bar gives a driver warning 80 feet from the track. It is operated automatically by approaching trains.

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POPULAR SCIENCE MONTHLY August, 1935 Smoothness of Illinois Roads Tested by Profilometer IX THIS day of the automobile and the heavy truck, roadmaking has an important place in state and town busi- ness. It is important to find what ma- terials and system of construction with- stand best the wear and tear of local conditions. It is for this purpose that Illinois employs the 32-wheel profilometer, il- lustrated above. It is a most ingenious device. The 32 wheels are controlled from a steering-wheel, set just off center, by a stranded cable that is connected with each wheel and crosses at center, thus giving an even pull on all the 32 wheels. A recording instrument, called the strainagraph,’’indicates on a record sheet every unevenness in the newly made road, ‘é Predicts Uses for Smoke _e dust from chimneys will, in the near future, find some commercial use in the industries either as filler for paint, fertilizer, or other products, or as a base for some building material, according to Prof. A. G. Christie of Johns Hopkins University. *Much work now is being done to de- velop methods of catching the fine par- ticles which fly up the chimney with the flue gases, he pointed out. — Know Your Car A STARTLINGLY large amount of the gasoline that is poured into auto tanks is wasted through improper carburetor adjustment and careless methods of driving. Another large amount is wasted yearly through small leaks in the carburetor and gasoline piping. A tiny leak, just sufficient to keep the bottom of the carburetor covered with a film of gasoline,-is often enough to drain the vacuum tank dry in less than a week if the car is standing idle. Remember these rules if you want the maximum gasoline mileage: 1—Never adjust the carburetor when the motor is cold. Change the setting only after the motor is heated up thoroughly. 2—Keep the mixture as lean as possible without noticeable loss of power. 3—Never race the engine while idle and avoid jamming the throttle wide open unless it is absolutely necessary. 4—Coast long hills with the motor shut off entirely. 5—Do not use the brake except in emergencies. Learn to shut off the power and coast to a stop with just a touch of the brake for the last few feet. New Eg¢ Crate ada England comes a new way of packing eggs. It consists of a light metal frame latticed with double cords that stretch from side to side. Light wooden partitions are threaded on the cords. Each egg is placed carefully be- tween the four cords and there held securely. This is said to reduce breakage. in fact, the needle actually records the exact profile of a road, from crown to sides, including curves and grades. This ma- chine enables the state to keep tabs on its road contractors. Coal Sizes Standardized H{OUsEHOLDERS will be glad to hear that, beginning this year, the anthra- cite coal industry will standardize coal sizes. Elaborate systems of screening are being installed at the anthracite mines, Stove coal for the kitchen range will drop through holes exactly 214 inches in diameter, and nut coal for the furnace through openings one and nine-sixteenths inches in diameter. Slate mixed with the coal will not ex. ceed in weight from 2 to 714 per cent of the delivery. Camera Photographs Stomach AN INGENIOUS camera that photo- graphs the interior of the stomach was displayed recently at Atlantic City, N. J. The apparatus consists of a metal tube that can be slipped down the pa- tient’s windpipe. At one end of the tube is a powerful electric light that illumines the stomach, and at the other end a special camera, with a series of lenses in between. The apparatus operates like a periscope, enabling the doctor to get a clear view of the patient’s stomach. Gas Auto Cleaner Uses Fine or Heavy Spray GAS-FIRED auto cleaner, the inven- tion of Garnet McKee of Rockford, Ill., is the newest device for automobile washing and removing paint or grease. It consists of a small steam-boiler, a con- tainer for the cleaning chemical, and a metal nozzle with two lengths of hose, one for carrying a high- pressure supply of steam; the other for delivering the special cleaning compound from the container. The compound is mixed with steam in the nozzle when power is turned on. When cleaning only is desired, a weak solution under low pressure is used. When Removing grease from a car with new steam-pressure apparatus paint or grease is to be removed, full- strength solution is said to remove all foreign matter almost instantly. Almost inaccessible or complicated parts are reached quickly and easily.

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sUSt, 1925 er ords the to sides, This ma- tabs on ed d to hear e anthra- lize coal ening are @ mines. will drop iches_ in » furnace ixteenths 1 not ex r cent of ymach it photo- stomach itie City, f a metal 1 the pa- ' the tube illumines er end a lenses in ites like a to get a ach. ray ved, full- move all mplicated easily. aratus August, 1925 POPULAR SCIENCE MONTHLY © rrailer Brake Is Controlled from Cab of Motor-Truck BRAKE that is said to give complete mechanical control of the trailer from the cab of the truck has just been developed by a Los Angeles trailer- manufacturing company. The new trailer brake is in two units— one installed in or alongside the cab, and the other on the trailer frame, just behind the front axle. The two units have a cable connection for setting and releasing the trailer brakes. This cable connection can be disengaged between the truck and the trailer by means of snaps, thus per- Motion-Picture Cameras Now Operated by Radio OTION-PICTURE cameras have been operated successfully by radio, according to reports from Universal City, California. A special device enables a camera to be placed at a point far distant from the operator and actuated by a transmitter. . This is expected to be of great value in photographing long landscape scenes— movie battles, for example, where several cameras have to be worked at the same time from different positions. Another new use for radio is in over- coming the fog menace on the Great Lakes. Seven stations on the lakes will be fitted with radio equipment that will send out warnings. mitting the use of the truck alone or with another trailer, and the use of the trailer with another truck. To set the trailer brakes, the driver operates a hand lever, closely resembling the hand brake on the truck. By press- ing down with his thumb on the push rod, he engages a dog in the ratchet on the drum, making the hand-lever brake integral withthe drum. Then, by pulling back on the hand lever, he winds the cable farther around the drum and thus sets the brakes. With this control the driver can alter- nate in the use of truck and trailer brakes on a long down grade, and as there is no need of running against low-gear com- pression as a means of braking, there is possible a distinct increase in the speed of transportation. Removable Truck Floor Permits Economical Replacement LOADING rocks and other heavy materials, the impact on truck floors often not only leaves permanent indenta- © tions, but creates strains that in time distort the entire truck body. Floors of heavy armor plate resist the shocks, but New Method for Reviving Asphyxiation Victims N INHALATOR device for adminis- tering to victims of asphyxia a mixture of oxygen and carbon dioxide (0.95 per cent; CO25 per cent) called ‘‘carbogen,”’ is the result of much study and research work by Drs. Yandell Henderson and Howard W. Haggard. The new device differs from other re- suscitating devices in that natural breath- ing is brought about by the use of carbon dioxide, which is Nature’s own means of stimulating breathing. Oxygen, when administered with a small amount of carbon dioxide, causes the patient to breathe more deeply and rapidly, thus consuming large amounts of oxygen, that flush from the toxic substances. It is claimed that Reviving an asphyxia victim with the newly invented apparatus pneumonia. blood any volatile ~ the inhalator gives the patient every chance of recovery without danger of the expense and weight of material of this thickness are too great. A manufacturer recently constructed a removable floor for trucks that is said to have great resiliency, and prevent trucks from being damaged. A layer of heavy creosoted planking is laid on top of the original steel floor. On top of this there is a protective covering of steel plate. The whole is bound together by flat- headed bolts. How Much Do YOU Know about Science? "TRE following 12 questions, each relating to some funda- mental fact of science, were se- lected from hundreds of queries sent in by the readers of POPULAR SCIENCE MONTHLY. How many of them can you answer correctly? Turn to page 116 and see how nearly you were right. 1. Why is it poor policy to cover the ice in the refrigerator with paper? 2. What is the highest tem- perature a person can stand? 3. Why can people who ap- parently have been drowned be revived by artificial respiration? 4. How can a bat fly in the dark without hitting anything? 5. Why does the moon seem to follow you if you watch it while you are walking? 6. What makes ocean cur- rents? 7. Why do colored clothes sometimes fade in the sunlight? 8. How are electric signs worked that are made up of mov- ing lights? 9. Why must the ground wire of a radio set be fastened to the water-pipe rather than to the gas-pipes? 10. Why do some flowers close up at night? 11. What does fear do to your liver? 12. Why is yawning catching? aecceeecce escesoco

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POPULAR SCIENCE MONTHLY August, 1925 New Household Aids for Improvements in Laundry, Kitchen, One Teaspoon at a Time After filling the inner section of this tea-caddy with tea, it -is placed in an outer section and the cone top illustrated at the left is adjusted. Once this top is in place, the caddy will give exactly one teaspoon of tea at a time; no other measure is needed A Compact Laundry For apartments where space is limited, a laundry outfit that can be attached to an ordinary sink has been devised. All the implements necessary for wash- ing clothes are arranged com- pactly, ready for use. The clothes are hung on rods to dry Spring Bottle-Cap Once this cap is adjusted on a bottle, it will remain until purposely removed. The cap fits in the slots on the bottle neck. Inside the anvil-shaped piece is a flat rubber stopper that is forced firmly over the mouth of the bottle oe Portable Dishwasher This dishwater requires no electric, gas, or water power to run it. After the dishes are placed in the wire holders, soapy water first is turned into the washer, the cover put on, and the handle turned. After rinsing, the dishes may be left in the racks to dry ie} Speedy Cookie-Cutter In spite of its simple shape, the cookie-cutter shown above is a hard worker. Once the dough is rolled, the cutter will cut a whole row of cookies in a second—its makers say “86 cookies a minute.”? The blades are made detachable Iceless Refrigerator An evaporator fitting into the ice compartment and run by water power, changes an ordi- nary icebox into an iceless re- frigerator. The water motor may be set in any handy cor- ner near by. A compartment in the evaporator freezes puddings, ices or liquids Electrically Heated Cup Shown above is a cup con- taining its own heating ele- ment, that will quickly heat any liquid, such as_ soup, milk, or water. Merely slid- ing the cup on the stand serves to make connection with the source of current Nine Tools in One This tool will pull tacks, scale fish, adjust gas-burners, open bottles and cans, serve as a stove-lid and hot-pan-lid lifter, may be used to makea tough steak tender, or as an ordinary tack - hammer Au

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set, 195 august, 1925 POPULAR SCIENCE MONTHLY 57 for | the Modern Housewife ben, and Bathroom Make a Shining Home A Hanging Oven The chief advantage of this electric oven hung on a bracket is that it can be placed wherever it is most convenient for the housewife, and, too, there is no trouble in keeping it clean b3 Adjustable Shelves ve By means of the fix- hape, tures shown above, above shelf brackets can be e the moved at half-inch ‘utter intervals to accom- okies modate utensils of S say different heights The eee A Folding Bathtub tor Useful for any one without a private bath, this fold- to the ing bathroom, illustrated “a by at center and extreme | ordi- right, is contained behind a a screen, and consists of a motor folding tub, water-storage , tank, with heaters, a tment basin, chest, and _ stool. inured When not in use the tub iquids folds up, over the tank ® Shoeblack Stand Compact and complete, the neat little shoe-polishing rack % BS te, a Opener for Flat Tins ly Every one has had trouble opening pagroed look — in ee Ip . tins such as contain shoe-polish. or bathroom. e extension The opener shown above is used by can be adjusted to two heights cup con- placing one of the flanged rings be- — any? a ——_- 0 iting ele- neath the tin, the other over it, then _ es there are ro — t . ckly heat pressing, and the tin opens easily, : polishing rag to run throug as soup, and without bending its edge rely slid- he stand .. Cal " : onnection Folding Ironing- “+ = 5 a e sia: Board and Seat | ¢ = . Illustrated below and zl * 1 One in two pictures at right €F ai P ' cks, scale is an ironing-board with ; : ‘ ers, open a seat attached, both } e y erve as a of which will fold up Sl beet vvy vue ot-pan-lid into comparatively ; : / to make a small space. The topof * or as an the board is adjustable - hammer for a lefts or right- handed operator, and is fixed in place by a turn of a thumbscrew New-Style Hand Brush In the picture above is shown a new style of hand scrubbing-brush. Be- sides the usual flat surface there is an indented end made especially for scrubbing the fingers individually. Nails are cleansed by rubbing them back and forth over the brush

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oe aS POPULAR SCIENCE MONTHLY Shoe with Hollow Heel Holds Handy Powder-Box Use of the heels of women’s shoes to carry small articles, such as latch- keys, pins, and even small change, is not entirely a new idea. But now there comes from London an odd new type of shoe with a hollow heel that serves as a powder-box. Whenever the wearer wishes to powder her nose, she simply releases a catch at the back of her shoe and the powder-box heel swings down on a hinge, giving access to the puff, as shown in the illustration at the right. Ir you treat fish ponds as pastures and fertilize them, you will catch more fish. A lecturer at the University of Munich, Dr. H. Fischer, gives this advice, based on recent experiments. He obtained the best results by using phosphate fertilizers. When potash salts were used, it was found by the investigators that the increase of fish was not so great. The hollow heel swings downward on a hinge, giving access to the powder-puff Four Veterans See the World in Auto Home AN INTERESTING round-the-world ever hit the “gipsy trails’ of the world. motor trip that began in 1921, was completed recently by Albert Carter, Goebel Reeves, “Piggy” Parks, and Jimmy Rogers, disabled ex-service men, in one of the oddest machines that On a Ford chassis a small, houselike structure was built, affording comfortable living quarters for the tourists. As they journeyed from place to place, the four travelers tacked license plates, posters, coins, stamps, and other souvenirs on the walls and roof of their conveyance. These bear evidence of the out-of-the-way places they have visited. The car has penetrated practically every civilized countryintheworld. The ex-service men passed through New York on their way to the New England states and to Boston, where the car will be placed on exhibition for two years and then sent to the Free Mu- seum at Washington, D. C., as a memorial to the dis- abled veterans of the World Odd round-the-world car, plastered with souvenirs War. August, 1925 Family without Fingernails Discovered in Italy FINGER- and toe-nail-less family of women was discovered recently by the scientist, J. A. Pires de Lima. Fo three generations no woman in the family has had a full-fledged finger- o, toe-nail. The investigations of de Lima show that in every other way the women are normal and healthy. Their seven brothers have full sets of healthy nails, Of three finger-nail-less daughters, one has been married and produced daughters who are also without finger- or toe-nails, Doctor de Lima has reached the conc. sion that this peculiar condition of the finger-nails is transmitted from mother to daughter as a result of an unusual case of sex-linked inheritance. Novel Cigar-Lighter Made like a Telephone A NOVEL cigar. lighter, in- vented by Sidney Stocking of Her. scher, Ill., is made to resemble a tele- phone. The re ceiver is a gas torch. When this is lifted from the hook, a valve is opened releasing a flow of gas that ignites automati- cally. The device is made in the shape of a desk telephone, as well as the wall style. Steamer Built to Submerge Low bridges that span the River Spree in Germany interfere with the pas sage of excursion steamers from Berlin. For that reason, it is reported, a new steamer to carry 1000 passengers will be equipped with large tanks which, when filled with water, will submerge the hull sufficiently to pass under the lowest bridge in the river. Schoolboy Builds a Model of Great Bridge DWARD WEBER, a 14-year-old high- school freshman in Philadelphia, be- came so interested in the new Delaware Bridge, under construction between his city and Camden, N. J., that he made a model of it. His only eo guides were newspaper - illustrations and his ma- terial,egg cratesand wire. Edward Weber, 14-year-old Philadelphia boy, putting the finishing touches on his zemarkable model of the new Philadelphia-Camden bridge Working after school, it took him two months to complete bis model. It is 12 feet long and cost two dollars. SECRET experiments with a magnetic bomb which, when within a certain radius of an airolane, is said to ‘‘respond to the magnetic influence set up by the metal parts of the plane,” are reported from England. The weapon is designed for anti-aircraft defense. Aus —es eS OD eed ~ eH Oo DM — ese ai

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August, 1925 ernails aly ess family of recent] Lima. es lan in the finger- op ; of de Lima - the women heir seven Ithy nails, ughters, one d daughters or toe-nails, the conely. ition of the n mother to sual case of Made e OVEL cigar. thter, in- by Sidney ng of Her. Ill., is made mble a tele. The re. is a gas When this d from the a valve is releasing a f gas that automati- device ig - telephone, merge River Spree th the pas. ‘om Berlin, ted, a new zers will be hich, when ge the hull west bridge dge 1k him two l. It is 12 magnetic tain radius ond to the the metal orted from signed for August, 1925 Fire Extinguisher Saves Pilot Five Miles Up FFECTIVE use of a fire-extinguishing E device nearly five miles up in the air recently saved the life of Captain Clauzat, a French altitude-record holder, when his plane caught fire. When Captain Clauzat saw flames bursting from the hood, he seized an ex- tinguisher and sprayed them until the fire was out. Later, in making a forced land- ing, flames again burst out and he had parely time to jump into the branches of a tree before his seat in the cockpit was enveloped in fire. Harbor Telephone Station Used by Rum-Chasers N THE blockade of rum-runners off the I Atlantic Coast the telephone, as well as wireless, has proved an important means of communication between govern- ment coastguard boats and officers on land. The picture below shows a novel sort of telephone station—a phone booth on the water—recently placed in Boston Harbor for use by rum-chasers. Its number is kept confidential. The telephone instruments are inclosed in asmall box fastened to the end of a log marker in the water. From the marker a cable runs under water to shore. When POPULAR SCIENCE MONTHLY Pressing the levers of this vending ma- chine prints your name on the pencil 59 Machine Prints Names on the Pencils It Sells A BORROWED pencil often fails to find its way back to the original owner. To make identification sure, and at the same time provide a handy means of purchase, a new vending machine has been designed to sell pencils stamped with one’s full name. By pressing various levers on the ma: chine, the purchaser sets his name up, letter by letter. The name can be checked for errors before turning the lever that prints it on the pencil. The machine holds about 300 pencils. WHILE we are interested in the excavation of ancient cities in Egypt and far places of the world, we are finding some at home. The other day, C. B. Cosgrove, an Ameri- can archeologist, discovered a buried Indian village on a ranch near Three Rivers, N. M. Two perfect rooms have been excavated so far. Skeletons were found in the smaller room. Dentist’s Traveling Office Serves Schools le PROVIDE expert dental service in rural districts, where otherwise it might not be available, a dental ambu- lance with skilled dentist and nurse is operated by the New Jersey Board of Health. With complete equip- ment, the dentist’s traveling office pulls up to the door-steps of rural schoolhouses, where it is awaited by willing patients. Black Tanks Waste Oil LACK cows are hotter than white cows. At least it seems so if one places his hand first upon the black then the white areas of a spotted cow standing in the sun. Recent tests have proved that the same thing is true of black-painted and white-painted oil tanks, and important use of this difference is the officer of a boat wishes to communi- cate with the shore, he simply runs his boat up to the log and puts in his call to the Boston Central. being made in the petroleum busi- ness to prevent the evaporation loss of stored crude oil. In recent tests it was .found that a tank painted aluminum or white, rose in temperature only 19 to 22 Army Mules Win from Truck in Tug-of-War iv YOU were to stake the pulling power of 24 mules in a tug-of-war against a motor-truck, which would you say would win? Such a tug-of-war actually was staged not long ago at Crissy Field, the Presidio, San Francisco. Twenty-four army mules, tugging at their traces, pulled a heavy army truck down the field backward, while the driver of the motor - truck was “stepping on the gas’’ and trying to make speed ahead. Twenty-four army mules are shown here winning a tug-of-war against a heavy army truck at Crissy Field, San Francisco, Calif. = The traveling dentist in his office degrees and Jost only nine per cent of its naphtha content. Ifit was painted black, it increased in temperature by 54 degrees.

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How to Install a Hot-Water Heater in Fireplace WICE as much useful heat is said to be obtained from a fireplace with the installation of an ingenious system in which the fire is used to heat water-pipes. It is the invention of Martin Dodge, a former member of Congress. The ordinary grate of the fireplace is replaced by a basket made of iron or steel water-pipes, in the form of a square coil, with an intake pipe at the bottom and an outlet pipe at the top. The outlet pipe leads to a steam radiator, located wher- ever it suits the convenience of the user. The pipe is connected at the top of the radiator. From the bottom of the radiator an outlet pipe leads to the intake of the fire basket. At a level slightly above that of the top of the radiator, and connected with its intake pipe, is a water-tank. This, when filled, serves as an automatic pressure regulator. When the fire is started in the basket in the fireplace, the water in the pipes is heated and rises, passing into the radiator and through it back to the bottom of the fire basket. Small quantities of water are added occasionally to make up for evaporation in the pressure tank. Nothing is required to build this heater that is not found in an ordinary hardware store, the inventor says. The pipes and elbows are of stock sizes. Radiators of any size can be used and an ordinary bucket for the pressure tank. POPULAR SCIENCE MONTHLY Selenium Protects Insulated Wires from Flames [LURING recent laboratory investiga- tions at Cambridge, Mass., to find new ways to make insulated electric wires flameproof, it was discovered that sele- nium had great value in preventing the spread of fire along the insulation. It was found that one part by weight of selenium protects 3.6 parts of cotton braid and 10 parts of rubber covering in the presence of 10 parts of copper conduct- or, contained in the usual No. 22 switch- board wire. Three milligrams of selenium thus protect a centimeter of length of wire, or one pound protects nearly a mile of wire. On application of a flame, it was found, much difficulty is experienced in getting the insulation to ignite at all. When ignited, however, and the igniting flame is removed, the flame usually goes out with- out appreciable spreading. The experiments were conducted in the laboratories of Arthur D. Little, Inc., in behalf of a wire and cable company. August, 195 This Device Turns Boiler into Washing-Machine 7° CONVERT a washboiler into 4 washing-machine, an ingenious de. vice consisting of two upright cylinders on a base, and fitting into the bottom of any washboiler, recently has been invented, Each cylinder has 32 holes out of which soapy water spouts when the water jg boiling and steam is generated. Its action is similar to that of a coffee percolaitor, The soapy water forced through the holes flushes the dirt out of the clothes, Folding Scaffold Brackets Aid Caspentons As* carpenter’s wood scaffold brackets may be converted into folding brackets by means of a newly invented metal attachment. The folding feature is important to the builder because he can move an entire equipment of folding brackets from one job to the next in a single load and store them in space not much larger than that needed for a toolchest. The parts of the attachment consist of a steel angle, a loose- hinged device, a length of light, strong chain, and a lock. Folding scaffold bracket and (left) parts of which it is made Now Tired Shoppers Can Wheel Their Bundles 5 ie RELIEVE women shoppers of the bother of carrying bundles, a French inventor has designed a shopping basket - which, when filled, can be wheeled like a baby-carriage. The basket is of wicker construc- tion, light enough to be carried ezsily. When it is empty, the wheels of the carriage fit inside the basket and the handle swings down over the sides. A grip is provided at the top. When it is to be filled with bundles, the wheels are removed and the handles swung back. Then the wheel axle is fitted and locked in brackets that are lowered at the bottom. The lid is locked down by the in- sertion of a pin through projecting loops, and the shopper is ready to wheel her pur- chases home. PROFESSOR VLADMIR KARAPETOFF, of Cornell University, has invented a five-stringed musical instrument that has the combined range of violin and ’cello. A fine depth of tone and shading are possible on How the basket is transformed into a carriage this instrument, it is said. Pure Silver Aluminum Made by New Process PURE aluminum, the goal of many years of research, soon will be avail- able in commercial quantities through the development of a new refining process. The term, “‘pure aluminum,” is, of course, still a relative one, but its use certainly now is justified because the new process makes this metal with less than two one hundredths of one per cent of impurity. Previously, the purest aluminum ordi- narily available contained 99.7 per cent of this metal. Some of the new product is as pure as 99.983. The principal impurity is copper, but traces of iron and silicon also are present. . Melted salts of sodium, aluminum, and barium fluoride are used in the process. The impure molten aluminum is carried by the electric current upward through the molten layer of these salts and is separated on top in a molten form from which point it can be poured or ladled off into molds. This pure aluminum has a beautiful silver color and luster which it is said to retain very well. —_ A wictm est oe} & a Pe ee

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August, 1995 iler into ne iler into a yenlious de. cylinders on ttom of any n invented, ut of which 1e water js . Its action ercolator, hrough the ie clothes, ters ade n Made | of many ll be avail- hrough the 1g process. ;, of course, e certainly ew process n two one f impurity. inum ordi- per cent of ‘oduct is as | impurity and silicon 1inum, and he process. is carried ‘d through Its and is form from r ladled off . beautiful it is said August, 1925 New Crawler Attachment Adds to Tractor Usefulness NEW crawler-tread attachment for tractors is said to permit the use of the machines under most difficult condi- tions—in sand, marshy lowlands, vine- yards, orchards, and over rough, uneven ground. In oil fields, where the traction is unusually treacherous, this equipment, which greatly increases the ground con- tact, is reported to be especially useful. The operation of the crawler attach- ment is independent of the tractor dif- ferential. Control is obtained through the use of two independently operating multiple disk clutches, one in each driving sprocket. This type of construction per- mits the full power of the engine to be applied to driving the track without imposing any strain on the tractor differ- ential, which is locked. , The attachment provides a tractive surface of from 900 to 1000 square inches. POPULAR SCIENCE MONTHLY Tractor with the new crawler attachment being operated on a plantation in Cuba Oil Pouring Is Simplified by Tilting Crate OR five-gallon cans a new tilting crate serves both as a shipping container and a device to permit oil or other liquids tobepoured from the can without lifting it. How the cover of the crate serves as a support for tilting the can The cover of the crate is designed with two side arms that serve as supports on which the crate can swing. When the liquid is to be poured, the crate and its contents are made to rest on these supports and tilted. When the can fit- ting in the crate is equipped with a spe- cially designedswivel spout, oil can be poured in small or large quantities with a mini- mum of waste and without soiling hands or clothing. When used as a shipping case, the base is swung around to serve as a cover for the can. First New Comet of the Year Discovered by Accident HAJN’S comet, the first to be dis- covered in 1925, which was picked up at the Simeis Observatory in the Crimea, Russia, was found as a result of a mistake in operating the telescope. This is re- vealed by Dr. Otto Struve, of the Yerkes Observatory, who just has received a de- tailed account of the event from G. Shajn, the discoverer, with whom he formerly was associated at the Pulkovo Observa- tory, near Leningrad. In making a trial exposure with a photo- graphic telescope that must be kept pointed at the object desired to be photo- graphed, Mr. Shajn moved the instru- ment the wrong way. This happened to be the direction and speed with which the comet was moving, so when the plate was developed, the comet was detected. If the telescope had been guided prop- erly, the comet would not have been noticeably different from the stars. Ingenious New Ice-Box Makes Cold Out of Heat N ARTIFICIAL ice-box that is said to operate like a coffee percolator and to generate cold from heat has been in- vented by two young Swedish engineers, Carl Munters and Baltzar von Platen. When heated at one point, either by gas, electricity, or kerosene, it cools the usual kind of food-chest and for ordinary house- hold purposes needs to be run only a few hours a day. When operated with gas at the Stockholm prices, it is said to produce the equivalent effect of eight pounds of ice at the cost of one cent. The ice-chest has no movable mechani- cal parts. Operation is initiated by heat that sets an ammonia solution in motion in a small boiler. The ammonia then passes through condensation tubes. While trickling down a generator, it mixes with hydrogen and by evaporating absorbs enough heat to cool the food. In a third cylinder, the ammonia is washed free from the hydrogen and then percolates through a set of tubes into the boiler again, where the heat once more setsitinmotion. Whilethis action is kept up, the refrigeration process continues. Split Pipe Stem Can Be Taken Apart for Cleaning ITH a stem that is split in halves, this novel pipe, can be taken apart easily for cleaning. The two parts are held tightly together by a decorative metal band that screws on a threaded part of the stem nearer the bowl. The makers of this new pipe declare the stem to be leakproof. THE new 16-inch guns now being placed at the Panama Canal can shoot a projec- tile weighing more than one ton a distance of 27 miles once every 50 seconds. Magnetic Case Designed to Sharpen Razor Blades CONTAINED in a small case of pocket size, an unusual magnetic device is said to sharpen safety-razor blades by straightening the blades’ edges. A blade fits between two pieces of wood and is slipped into the case, which has sides of highly magnetized metal. The metal, it is claimed, pulls the edges of the blade straight through attraction. Sharpening is done by leaving the blade in the case. If left there between shaves, the blade always will be ready for use, the inventor asserts. Inserting razor in magnetic sharpener

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62 POPULAR SCIENCE MONTHLY August, sii whit ibis Spectacular New Mammoth Passenger Planes Broncho Buster—Other New Air-Cooled Motor A ‘Flying Fish”’ Driven by a _ new air-cooled Because of its odd fish-shaped motor (left), a navy torpedo body, this eight-seater passenger plane recently completed a 230- biplane, recently constructed in mile test flight in 110 minutes —a England for commercial use, has record for planes of this type been called the Flying Fish Germany’s New Air Wonder So great is the wing spread of this steel-ribbed monster of the skies that 60 men can stand side by side from one wing tip to the other. The machine, a monoplane, will be used exclusively for com- mercial purposes. It is driven by three propellers, one at the center and one on each of the wings. Two pilots are needed to guide it. Despite its size, the monoplane accommodates only eight passengers Picking Up Mail on the Fly This picture shows how one of Germany’s air- mail planes picks up a mail-bag without stopping. The bag is attached to ropes strung between two poles, and the pilot, flying low, drops an anchor that catches the ropes The First Aerial Cowboy “Let ’er buck!” yelled Bob Rose when, in Los Angeles recently, he strapped his cow-pony saddle to the back of an airpiane and hung on while his aerial steed twisted and turned cM YO we_.

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Ugust, 1925 ~W 2¢S— ) ther h’”’ h-shaped assenger ructed in l use, has 18 Fish er -el-ribbed d side by machine, for com- ropellers, gs. Two size, the assengers August, 1925 Achievements in A Flying Ambulance—Aerzal Oddities of the Sktes POPULAR SCIENCE MONTHLY The World’s Smallest Dirigible The future of lighter-than-air “yachts” is forecast by the world’s smallest dirigible, recently completed in Italy by Col. Umberto Nobile. It is only 105 feet long, and the vol- ume of its gas bag is only 35,000 cubic feet Airplane Ambulance This novel machine, ex- hibited in France, has a small compartment, open- ing from the side, for the ambulance stretcher Nobody Was Hurt A French pilot not long ago acci- dentally landed on the roof of the plane’s hangar near Paris; with the startling result pictured at the left Flight | Remarkable Rotor Propeller for Airplanes Fifty-per-cent increase in pulling power is claimed for an unusual new rotor propeller for airplanes designed on some- what the same principle as the Flettner rotor sailing-ship Huge Flying-Field Lantern Light radiates in all directions from this huge searchlight, imported from France for use on the air-mail landing-field at Cleveland, Ohio. It illuminates an area within a radius of three-quarters of a mile Garage-Sized Biplane In a test at Lincoln, Neb., this baby biplane is reported to have traveled 100 miles an hour. It weighs only 350 pounds and fits in a garage

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The post-officé and telephone booth POPULAR SCIENCE MONTHLY Automatic Post-Office also a Telephone Booth N AUTOMATIC post-office that sup- plies stamps, receives letters, and provides telephone service, all without the assistance of an attendant, has just been built by the British postal authori- ties at St. Martin’s-le-Grand, London, not far from the General Post Office. It is an experimental structure intended for erection at Bath, Somerset, and other stations as a substitute for temporarily closed postal offices. If the new post- office kiosk proves a success, similar structures may be installed in busy streets as a permanent system. The kiosk is about nine feet high and 3.14 feet wide. The inside is designed as a soundproof telephone booth. The let- ter-box is built into the back of the kiosk and above it are the stamp machines. At night the automatic post-office is illu- minated by an electric lamp and the signs, “Post - Office,’ ‘“‘Stamps,’” and ‘“Tele- phone,” also are illuminated. Periscope to Protect Bank Vault from Bandits has an outlet or peephole set in the stone facing of the building. By this means any one approaching the doors of the vault intent on robbery can be observed by an officer from the outside of the building where vault is installed. The picture at the left shows the peri- scope installation in the interior of the vault, with a sighting tube that leads to the peephole on the exterior, which is shown in the illustration below. AS A protection against bandits, a bank at Portland, Me., re- cently fitted its safety vault with a periscope through which a police- man on his rounds is enabled to view the interior of the vault from the outside of the bank building. The periscope, consisting of an optical system of prisms and lenses, is concealed inside the vault, and The periscope apparatus in bank Vault (left) and the peephole outlet in front or street wall of bank — Compact Curling-Iron Fits in Vanity Case ‘T HERE always seems to be room for just one more accessory in a woman’s vanity case; and so she undoubtedly wil] find room for one of the latest novelties— a handy little curling-iron. It will fit into a case less than 414 inches long. The new curling-iron is contained in g telescoping metal tube which, when ex. tended, exposes a small spirit burner, When this burner is lighted, as shown above, the flame heats the metal of the iron, which must not be allowed to get too hot, as it is harmful for the user’s hair and the iron itself. Bacteria in Hailstones | Fens since the discovery, a few years ago, that fog and rain are caused by the condensation of water vapor around nuclei consisting of small particles of mineral or organic matter that had been carried by warm air currents to great heights, R. Dubois, a noted physiol- ogist of Lyons, France, devoted con- siderable study to this subject. With great care and infinite patience he col- lected droplets of fog and rain, crystals of snow and hailstones, and submitted them to a microscopic examination. In most cases Mr. Dubois found that the nuclei of condensation consisted of extremely fine particles of organic or mineral matter, volcanic ash, pollen of conifers, and other plants. Particularly interesting is the fact that recently he discovered that in many cases hailstones were formed by condensation of water vapor around microorganisms of a type resembling that of certain phosphorescent bacteria. Among them was found a microorganism heretofore unknown, which he named Bacillus grandiosum. The bacterium resembles in form that of a shoe sole and its color is a delicate red or rose. average for other men in his class. “Mechanical Brains” ‘Two different types of “mechanical brains’—machines that perform the most complicated mathematical problems auto- matically—recently have been perfected separately by two young inventors, Frank P. Gage of Boston, Mass., and Stuart C. Dodd, a graduate student in Princeton University. Both are expected to prove of great importance in psychological and educational research, and in industrial statistical work. The Gage invention has aroused keen interest among students and professors at the Massachusetts Institute of Technology, where it has been tested. The inventor claims his device has the mechanical ability to solve within an hour a mathematical problem that ordinarily takes three or four days to solve. Dodd’s invention is known as a correlation machine, de- signed to indicate how much one set of facts is the cause of, or is related to, another set. It solves quickly the most difficult problems of algebra. It is said to be so constructed that by its use insurance companies can determine a man’s expectancy of life by comparing his physical ailments and habits with the Do Algebra Frank P. Gage (left) with Herbert R. Stewart, working on machine | f J I ] 1 i ]

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. Fits in be room for 1 &@ Woman’s ubtedly wil] novelties— ; Will fit into ng. itained in g a, when eX. irit burner, |, as shown netal of the d to get too r’s hair and bnes ry, a few d rain are 1 of water ng of small matter that currents to ted physiol- voted con- ject. With nce he col- ,» crystals of nitted them found that -Onsisted of organic or 1, pollen of Particularly recently he s hailstones n of water s of a type sphorescent s found a 10wn, which um. The .at of a shoe red or rose. machine August, 1925 Draftsman’s Fountain Pen Is Made Adjustable OR the use of draftsmen, mechanical engineers, and professional men, a new fountain drawing-pen has been devised. As with the ordinary drawing-pen, it can be regulated to give any stroke, from a hair line to a bold line, and as it works on the same principle as the fountain pen, it can be carried conveniently in the pocket. Derelict Ship Wanders Seas for More than Two Years RIFTING about on the Atlantic Ocean, the dread of hundreds of skippers, is a ship like the Flying Dutch- man, without crew or sails. For nearly two years she has been wandering with- out guidance. A. B. McManus, of the Hydrographic Office of the U.S. Navy, believes that she now is headed toward the Sargasso Sea. The ship sailed in September, 1923, from Nova Scotia for Brazil, with a cargo of lumber. A severe storm came, dam- aging her severely. The crew was rescued and the ship abandoned. The lumber cargo keeps her afloat. Once she was reported on fire by a vessel that sighted her, but when seen again the fire was out. Once a coastguard cutter took her in tow, but struck a gale and she was again a wanderer. No one knows where the derelict is now, which makes her very dangerous to others. A BRONZE tablet has been placed in Menlo Park, N. J., on the spot where Thomas Edison perfected the electric ‘light, the phonograph, and the motion- picture machine. The inscription reads, “On this site 1876-1882 Thomas Edison began his work for service for the world to illuminate the path of progress and lighten the labor of mankind.” and extraction openings, POPULAR SCIENCE MONTHLY Dispensing Machine Makes Paper Drinking-Cups you manufacture your own paper cup as you turn the crank of a new dis- pensing machine, pictured at the right. In the same operation the completed cup drops into a receptacle, ready for use. America uses forty million paper cups a day, and this recent invention was de- signed to cut down the cost of making them. A roll of white paper fits in the ma- chine. A simple mechanism shapes the cup and makes it water-tight without the use of paste or glue. EUROPE has a real skyscraper. It is in Cologne, Germany, and towers all of nineteen stories high. While Europeans say that it is an American model, Ameri- can travelers deny the resemblance. It is of heavy red brick, with no ornamenta- tion and is said to look like some medieval castle rather than like one of our own efficient looking office buildings. Pressing a lever forms cup Fresh Air for Every London Councilman AN UNUSUAL system of air ventilation installed in the London County Coun- cil Hall in London, England, makes it possible for each member of the Council to control, independently from his desk, the condition of the air immediately surrounding him. This is accomplished by an arrangement of supply Machinery for conditioning the air. Above: View of council hall, showing individual ventilators placed so that by manipulation of a lever beneath the desk the occu- pant can direct the flow of air upon himself or upward into the general atmosphere. Thus the air of the chamber constantly is being re- moved and renewed. The entering air is heated and humidified in the winter; cooled and dehumidified in the summer. The apparatus for washing and conditioning the air is situated under the Council Chamber. a Conrad Schickerling, with three types of his filamentless bulbs them. hum and noises. Fwd} of the new radio tubes. Light Bulbs without Filaments HROUGH the invention of an electric-light bulb that re- quires no. filament, Conrad Schickerling, of Newark, N. J., claims that municipal lighting bills may be cut in half. A 500-watt lamp of the new type, he says, will burn twice as long as filament lamps and consume less than half the current now required. The inventor also has made lamps of two-watt size for use on signs. These, he declares, will reduce the cost of current to 20 per cent of its present level. Auto lamps of two candlepower and higher, without filaments, also have been tested. An advan- tage claimed for these is that jarring will not injure nor break Still another invention of Schickerling is a vacuum tube with- out filament or grid, designed especially for alternating-current rectification in radio B-battery eliminators. He claims the tubes produce perfect rectification, devoid of all alternating-current In the photograph the inventor is seen holding in his hand one On the table are a large electric-light bulb of 500 watts and a smaller one for use on signs.

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How to Construct a Compact | An Ideal Portable Uni Fig. 1—This picture shows the extreme compactness of the two-tube receiver. It weighs only three pounds, and can be held in the palm of one hand HE word “‘portable”’ as applied to radio receiving sets seems to have many meanings. At one end of the scale we have portable radio sets that are moved around about as easily asa heavily loaded trunk. At the other we have sets built around toothbrushes, in- side thimbles, and similar queer con- tainers. The two-tube receiver described here approaches neither extreme. It is simply a good two-tube unit built of standard parts and made as compact as possible. Every radio fan has his own ideas as to how to make up a portable outfit, and so several sketches are shown on these pages that will help you to decide on an ar- rangement best suited to your own par- ticular needs. The set operates with two three-volt dry-cell vacuum tubes and a plate voltage of 45. It is possible, therefore, to run the set using two standard C batteries in parallel for the A-battery supply,‘and two AND ANTENNA WIRES Fig. 3—Here is a suggested method of hitting the set into a portable case. This idea can be modi- fied easily to suit your own particular needs POPULAR SCIENCE MONTHLY Fig. 2—Rear view of the little two-tube receiver. All parts are lettered and numbered to correspond with the list of parts to be found on the opposite page of the small B batteries in series for the plate current. The receiver itself as shown in the illustrations weighs just a shade over three pounds, so a complete outfit consisting of a light case, batteries, head phones, and wire for antenna should not prove a burden. Of course, for regular use at home you naturally will prefer to use the large size A and B dry cells because they are much more economical. The circuit is, in many respects, similar to that used in the one-tube receiver described in the May number of POPULAR SCIENCE MONTHLY. The main difference is that the tickler coil C in this month’s receiver is movable instead of fixed, and a fixed condenser is used instead of the variable one shown in the May set. This change does not affect the quality of reproduction, however. The receiver has been tested and ap- proved by the Popular Science Insti- tute of Standards. ‘Tests in the Insti- tute Radio Laboratory show that it gives exceptional selectivity, distance, and quality. In fact, the results show that, in spite of its small size, it gives as fine radio reception as can be expected from two tubes. Connected with a 50- to 100-foot antenna hung from any con- venient tree, and a ground wire thrown into a near-by brook or lake, this portable outfit will bring in distant stations with excellent volume on the head phones. The conventional shape of the receiver also makes it useful for regular use at home in cases where it is desired to keep the amount of space occupied by the radio equipment down to the minimum. There is no stan- August. 1925 for Summer Weighs But Three Pounds By Alfred P. Lane dard size of radio cabinet small enough to fit this receiver, however, so if you -want to install the unit in a conventional typé of cabinet, you will have to build the cabinet yourself. If you do not want to go to the trouble of building a complete cabinet, a simple dust cover out of cigar box wood will be satisfactory. HERE is just one point about the construction of this receiver unit that may cause the beginner some slight trouble, and that is the difficulty of making the connections between the various instruments because of the lack of space in which to work. If you have any doubt about your ability in this respect, the remedy is to spread out the instru ments a bit by making the panel and base board each an inch longer. The parts you will need to build the receiver are listed at the top of the opposite page. In selecting the parts for your receiver, the size of each part must be carefully considered. The tuning unit A, B, C is a standard small-sized three-circuit tuner. For the benefit of those who prefer to build this part of the receiver, the primary coil A consists of 9 turns of wire, the secondary coil B is wound with 53 turns, and the tickler coil C has 16 turns on each side of the shaft, making a total of 32 turns. The form on which coils A and B are wound is 21% inches in diameter, and the _tickler coil form is 1% inches in diameter.

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August. 1925 act eC Unis cighs inds ne ll enough to if you -want itional type > build the not want to a complete ut of cigar about the ceiver unit some slight ifficulty of tween the f the lack of u have any his respect, the instru el and base > build the (op of the ur receiver, e carefully a standard *. For the » build this vary coil A » secondary is, and the ach side of turns. The re wound is the tickler diameter. August, 1925 Two-lube Set The Parts You'll Need H® are the parts you will need for the two-tube portable unit: A, B, and C—tuning unit D—variable condenser, mfd. E—grid condenser, .00025 mfd., with grid-leak clips F—fixed condenser, .0005 mfd. G—theostat H—audio transformer, 5 to 1 ratio J and K—vacuum-tube sockets L—grid leak, 5 to 7 megohms M—composition panel, 414 by 7 inches N—wooden baseboard, 6 by 6% inches O—composition _ binding-post panel, 134 by 64 iaches Eight binding posts, three-inch dial, bus wire, tubes, batteries, etc. .0005 ‘Number 24 double silk-covered wire will do very nicely. Any standard type of variable conden- ser can be used at D if it is small enough to fit into the space limitations. HE vacuum-tube sockets J and K in the model receiver are adapted to the 8-volt dry-cell type tube, but there is sufficient room to permit the use of stan- dard storage-battery tubes if you desire, and this change would be a desirable one for the man who is going to use the set on an auto-camping trip, since the storage battery on the car is handy for use as an A battery. Some form of spring-base or cushion-type socket is worth while, of course. The rheostat G of the model receiver has a resistance of 25 ohms. If you use 6-volt storage-type tubes or 11% volt dry- cell tubes, the rheostat should have a resistance of 10 or 6 ohms respectively. Because of the space limitations, the building and wiring of this receiver re- quires more care and time than a similar receiver of standard size. This means that you will have to study carefully the placing of each wire so that it will not interfere with other wires. The laying out and drilling of the panel Fig. 6—Side view showing the hook-up of the tuning coil POPULAR SCIENCE MONTHLY is the first operation and inthis you will be aided by the diagram in Fig. 8 on page 118. But before you start drilling any holes, make sure that the instru- ments you have purchased will fit. If, for instance, the variable condenser D or the rheostat G are larger or of a differentshapethan the ones used in the mod- el receiver, you may find it necessary to use a slightly longer or higher panel to keep the _ instruments from touching each other. After you have cut the panel to the proper size and drilled the holes for the shafts of the variable condenser D, the rheostat G andthetuning unit A,B, C, together with the screw holes to hold the panel to the baseboard, you can proceed to mount these in- struments andthen attach the panel to the baseboard. Next mount the audio transformer H and the sockets J and K on the baseboard. The primary terminals of the audio trans- former H should be toward the binding- Fig. 4—View of the set from above. ously the instruments are arranged to conserve space 8765 4321 Fig. 5—Pictorial wiring diagram for be- ginners who are unfamiliar with the symbols 67 Notice how ingeni- post panel and the grid terminals of the sockets should be near the front panel and at the left (as seen from the rear) if you use the 3-valt dry-cell tube sockets. Study Figs. 1, 2, 4, and 6 carefully before mounting the instruments. It is a good idea to leave the binding- post panel off until some of the wiring connections have been made. If you use the ordinary screw-type binding posts, it will be advisable to hold the panel in place while each wire is bent into shape. Then, when you have the wires ready, you can clamp down the binding posts on the binding-post panel and put in the screws that hold the binding-post panel. yr you are satisfied that the instruments are mounted correctly, you can proceed with the wiring as follows: Connect the filament terminals of sockets J and K, which are nearest the front panel, and run a branch from this wire down between transformer H and socket K and over to binding post No. 4. Continue this wire over to binding post No. 2. Next, run a wire from the F terminal of transformer H dowr to bind- ing post No. 3 end continue it around to one terminal (Continuec on page 118) 3 a 4 o V¥VVV¥ G) 26 GRD. -A +A Fig. 7—Wiring diagram with parts represented by radi» symbols ( f P| a 8e +45 €PHONES L i a -B

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68 POPULAR SCIENCE MONTHLY Summer’s the ‘Time to Overhaul Your Set How to Prepare for Good Reception By E. R. Haas HE coming of summer affords us all a chance to take stock of our radio equipment and to do the necessary overhauling that will put our apparatus in extra good shape for another season’s use. On nights when static is exceptionally bad, the overhauling can be done without the feel- ing that some impor- tant broadcasting is being missed. Haphazard digging around in the receiver with a screwdriver is not the right way to go about a systematic overhauling. To begin with, you should make a list of the things that ought to be looked in- to, such as the list on this page, and then you can place a check mark against each item as soon as you have attended to it. Since it is logical to start at the top, we can begin with the antenna. What is needed to put your antenna system in good condition will depend on how good a job you did in the first place and on how long it has been in place with- out attention. If you used a plain copper wire and the antenna has been up for more than six months, the chances are that the copper has corroded so that the surface is no longer smooth and shiny. The rough surface offers some resistance to the passage of high-frequency current. You can, of course, polish the surface of the wire with fine sandpaper, but you will find it much more satisfactory to re- new the antenna completely with enameled copper wire. The enamel coating stays on the wire for years and protects the surface of the copper from corrosion. HE insulators should be wiped care- fully to remove grime that collects on them and acts as a high-resistance leakage path for the minute electrical currents in the antenna circuit. You can’t be too careful to support the antenna rigidly, for the weight of a long antenna covered with a thick layer of sleet is considerable. The connection between the lead-in and the antenna should receive careful atten- tion. Corrosion at this point will cause weak signals and may result in noisy re- ception. A carefully soldered joint where the solder actually has flowed on the sur- face of both the antenna and the lead-in wires, will not give much trcuble, but if the wires merely are twisted together without soldering, it is a good plan to cut the lead-in, scrape another clean place on the antenna, and twist a new joint. If For Good Contacts To assure good contact between the tube prongs and springs in the socket, clean the tips of the prongs with a piece of sandpaper How to Locate Loose Connections Disconnect antenna and ground; then, with tubes lit and B battery and loudspeaker con- nected, push each wire in turn with the cap end of a fountain pen. Scratching or clicking noises indicate a loose wire that must be found you are putting up a new antenna, try to make the antenna and lead-in a con- tinuous piece of wire. The illustration at the bottom of this page shows how to do it. The next task is to test all the connec- tions within the receiver itself. The easiest way to do this is to disconnect the antenna and ground; then, while the tubes are lit and the B battery and loudspeaker connected, push against each wire in the receiver with the end of a wooden stick or the end of a hard rubber fountain pen. Also press against the tubes themselves. Continuous Antenna and Lead-In ANTENNA August, 1925 If you are putting up a new antenna, try to make the an- tenna and lead-in as shown above. No- tice how the wire is passed through the insulator and wound around the antenna wire tens, Check These 10 Points 1. Clean insulators and renew antenna with enameled copper wire. 2. See that antenna supports are strong enough to with- stand winter storms. 3. Inspect connection be- tween antenna lead-in and antenna. . Tighten loose binding posts, . Test all connections. . Make sure that. contact prongs in tube sockets are making good contact with tube terminals, 7. Clean thoroughly the in- terior of your receiver. 8. Inspect ground connection, 9. Look over Aand B batteries, 0. Inspect flexible cords of phones and loudspeaker, aoe If this procedure results ip scratching or clicking noigeg in the loudspeaker, you may be sure that the wire being tested is loose at one end or the other. In making this test, re. member, however, that the contact between the prongs of the tube and the springs in the socket is rarely so per. fect that no noise whatever will be heard when the tube is touched. To be sure that you are getting the best con- tact possible, it is a good idea to bend up the springs in the sockets a bit and clean the prongs of the tubes with a piece of sandpaper. After you have made sure of good con- nections, clean the inside of the receiver thoroughly. This means dusting off every part as carefully as possible, not forget- ting to run a pipe-cleaner between the plates of the variable condensers. The ground connection, because it is indoors, is not subject to corrosion as is that between the antenna and the lead-in, If you made a good ground connec. tion when you first installed the receiver, you can be reasonably sure that it is still in perfect condition. RY-CELL A and B batteries require no special attention other than to see that all connections are tight. With storage batteries, however, it is a good idea to clean off the tops and ter- minals with a rag moistened with ammonia and then grease the terminals with vase line. Your storage A battery may have been on the job for several years and you now are beginning to wonder whether it still is good for another year’s service. There are two almost infallible indications of deterioration. One is the failure of the battery to hold its charge while standing idle. This usually means worn-out sepa- rators. The other is the failure of the hydrometer reading to go above 1260, regardless of how long the battery is left on charge. A low hydrometer reading when the battery is as completely charged (Continued on page 119)

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August, 1925 SOUCESUEESEEGEEN,: 4 CLL LLL LLL LLddiiddelelebaad SCUSCeeeeeeneaengs; 2 results in king noises r, you may > wire being one end or that the the prongs the springs rely so per- e whatever e sockets a the prongs ith a piece f good con- he receiver ng off every not forget- etween the ers. 2cause it is rosion as is the lead-in, d connec- he receiver, at it is still ries require than to see rht. With it is a s and ter- h ammonia with vase- have been n-out sepa- lure of the bove 1260, ttery is left ter reading ely charged August, 1925 Latest Novelties of Broadcasting Radio in a Cave and on a Motor-Boat—New Inventions New Power Tube Professor Holweck of Paris has just perfected a new demountable vacuum tube (below) rated’at 100 kilowatts. Instead of pumping all the air from the tube and then sealing it, the inveator mounts it ona remarkably efficient vacuum pump that is kept running while the tube is in full operation Broadcasts Races Station WJZ, New York, re- cently gave a vivid account of a college boat race by rebroad- casting signals from a motor- boat (below) equipped especially for low-wave transmission POPULAR SCIENCE MONTHLY NewLoudspeaker E. W. Kellogg and Chester W. Rice are shown above examining a hornless loudspeaker they have perfected. It operates on the electro- dynamic principle and uses a paper cone about six inches in diameter Skeleton Mast The mast of a new radio station in Moscow, Rus- sia (right), is built in an extended basket-weave fashion. It is claimed that the structure is very rigid in the wind Radio in a Cave Working 300 feet underground, Mr. Fortous, of the Milwaukee Public Museum, found that radio relieved the tedium of his work in making a model of a Virginia cave

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Tests by Popular Science Institute of Standards Reveal POPULAR SCIENCE MONTHLY August, 1925 Surprising Facts about Tuning Coils By Thomas Vanacore N ADDITION to our | regular test work in the Radio Laboratory of the Popular Science In- stitute of Standards, we are constantly carrying on research work along vari- ous lines and occasionally the results obtained play havoc with some of the accepted ideas on good radio construction. Take the matter of radio tuning coils, for in- stance. Every radio fan who builds sets, and nearly every buyer of a factory- built receiver, has ideas as to what constitutes a good tuning coil. Some prefer cotton-covered wire. Others insist on silk. Many persons also are prejudiced in favor of vari- ous kinds of basket-weave coils. === A series of tests covering every conceivable kind of radio tuning coil would, of. course, be far too long to describe here, but the results of a careful series of tests on plain cylindrical coils just completed in the Institute’s Radio Laboratory, are so amazing that we feel sure every reader of POPULAR SCIENCE MONTHLY who is interested in radio will want to know about them. To begin with, we wanted to find out what advantage, if any, there was in silk-covered wire compared with cotton- covered and enamel-insulated wire, since these three kinds of wire are most in use. Also, we wanted to settle the question as to what effect moisture has on coils. This is highly impor- tant because a great deal of Making the Moisture Test Here is part of the apparatus used in the Radio Laboratory of the Popular Science Institute of Standards to test the effect of ‘moisture on tuning coils. Three coils were hung for three hours in a cabinet containing a pot of boiling water on an electric stove set-builder if he wants to wind coils with insulation other than that spec- ified in the instructions for construct- ing the set he is working on. They enable him to determine accurately the proper number of turns needed with any one of the three kinds of wire when three-inch tubing is used. So much for the matter of wave lengths and actual constructional data. Now we come to the results of our tests. We found that cotton-covered wire under these particular conditions is better for radio use than either silk covered wire or enameled wire. The chart on this page, showing the comparative resistances for the various kinds of wire, tells the story in graphic form. Of course, the difference is not great and, in fact, it is doubtful if any appreciable difference could be no- ticed in signal strength under actual working con- ditions. Nevertheless, the fact remains that cotton is just a bit better then silk. HAT effect has mois- ture inthe air onthe efficiency of radio coils? We hung all three coils in a metal box containing an electric stove under a pot of water as shown in the illustration. The current was turned on, the box closed and left for three hours. On opening it we found the water nearly all boiled away, water was running down the metal sides of the box and the air in the box was as damp as the air in the tropics after a severe rainstorm. We hustled the coils over to the test bench and repeated our resistance tests. There was no change—the meters read exactly the same! We could hardly believe the result our- selves, it seemed so at variance with.all of the theories on the subject. Toleaveno room for doubt, we took the coil wound with cotton-covered wire and deliber- ately put it in a pail of water and the poor reception in summer is often blamed on moisture in the coils. + O MAKE the test a fair one, we used just one size of wire and one size of composition tub- ing. We first wound three coils, of 44 turns each, using the three kinds of wire. The lengths of the windings of the different coils were as follows: = nN GG RESISTANCE (OHMS ) N co wo 8 te | Curves show radio- frequency resistance of three 44-turn coils, No. 22 wire, each wound on three-inch bakelite tubing hav- ing a 1/16-inch wall 250 300 350 400 450 500 WAVE LENGTH (METERS) 550 left it there for several minutes. Then we took that coil, with the water actually dripping fromit, and put it back in the test circuit. HERE was no doubt about the resistance under these conditions. It was nearly seven times normal, but the startling fact that confronted us was that within a few minutes, even while the water was still dripping from the coil, the meter readings began to go up and before the coil felt dry to the touch the resistance had returned to normal. Think of it! Here was a coil so wet that you could feel the damp- ness in it, and still it was ap- parently perfectly good for radio use. These tests would seem to indicate that, short of deliberately allowing rain to fall in a radio set, No. 22 d.c.c........ 19/16 inches ee ee ee 11/4 inches No. 22 enamel....... 11/8 inches To cover the broadcasting wave-length range most effec- tively with a tuning condenser having a maximum capacity of .0005 mfd. we found that the num- ber of turns required are: OE Co taw se wakaies ova 48 turns a ee re 45 turns EE SL eee 44 turns These measurements are partic- ularly interesting to the home Comparative Efficiency of Coil Wires This chart, showing the comparative resistances (in ohms) of three types of insulated wire at varying wave lengths, indicates that cotton-covered wire is the most efficient for radio coils or pouring a bucket of water over the apparatus, moisture can have little or no effect on reception. (Continued on page 117)

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sust, 1925 ils articular tter for cher silk nameled is page, parative various ells the rm. Of ice is not t, it is reciable be no- strength ‘ing con- less, the 5 cotton er then as mois- ir onthe iO coils? > coils in ric stove n in the ; turned or three und the ater was the box np as the instorm. the test 1ce tests. ters read sult our- ith all of Jeave no il wound deliber- ater and minutes, with the ym it, and cuit. ot about or these ‘ly seven startling was that ‘en while ing from gs began coil felt ance had a coil so he damp- was ap- for radio seem to liberately radio set, ater over can have ‘eception. 7) Avgvst, 1925 Useful Ideas to Aid the Motorist Dog’s Coupé an Amusing Novelty Baggage Trailer for Light Cars From France comes the solution of the excess-baggage problem. The frame is hinged at the front and the wheel is set at an angle to make it trail properly Windshield is a novel idea for protecting the mo- torist’s face. curved Here English screen is made of clear cellu- loid and is pivoted on two press but- tons fixed to the side of the cap so that it can be swung out of the way POPULAR SCIENCE MONTHLY The Checks Wheel Alinement This new wheel aliner in- stantly shows alinement by pointers on dials. It measures the pitch and the toe-in. The reading on the dials is checked against a chart, which gives correct pitch and toe-in for each make of car Centrifugal Air Cleaner for Autos Incoming air is made to rotate rapidly by directing vanes and the dust settles into the detachable container illustrated at the left Hydraulic Auto Lift Non-freezing oil under pres- sure is used to operate this remarkable auto service plat- form. Compressed air drawn from the same reservoir, used for tire inflation, is used to obtain the necessary pressure Ford Crankcase Brace This brace is applied easily to the crankcase of the Ford engine. It aids in preventing the breaking of the crank- case supporting arms and helps to make the whole assembly more rigid. Vibration is cut down by this means De Luxe Compartment for Dog William Sykes of Los Angeles has had this unique runningboard coupé built for his dog. glass windshield, side curtains, and all the automobile comforts enjoyed by his master It has a

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"Are Your Headlights Safe? height T WAS eight o’clotk at night, but Gus Wilson and Joe Clark, proprietors of the Model Garage, were still at work. Gus, the mechanic of the firm, was put- ting the finishing touches on a car he had promised to deliver in the morning to a man who was starting on a vacation tour, and Joe, who ordinarily held up his end of the partnership by taking care of the office work only, had been forced by the midsummer rush of repair jobs to roll up his sleeves and become for the time being a mechanic’s helper. A smart touring-car suddenly shot in from the street and came to a stop in the center of the garage floor. ‘*Hey, how about some gas?” POPULAR SCIENCE MONTHLY How to Adjust Lights Gus tilts the customer’s headlights downward so that no part of the beams will rise above a line on the garage door marking the maximum permitted by the law the other fellow? He hassome rights, too, you know. Swing your car around so that the lights will be facing the back door, and I’ll show you what I mean. There, that’s far enough,” called out Gus, as the beams from the headlights lit up the whitewashed door. ‘‘Now step up close here. See that black line across the door? The law in this state says that no part of the beam should go higher than that. Your lights, though, are ad- justed so that at least half the beam is above the line.” **T know that,”’ the car-owner broke in, “but if I tip them down, I can’t see the Gus, the Veteran Mechanic, Shows How to Adjust Them to Avoid Dangerous Glare August, 1995 By Martin Bunn road far enough ahead when I drive fast.” ‘Quite true,” admitted Wilson. ‘But you’re violating the law just the same, Suppose everybody else thought as you do, and used blinding lights and drove like —er—lightning? Why, there wouldn’t be hospitals enough for the victims—or tow cars enough to drag away the wrecks! bes days of fast night driving with daz zling lights are gone forever. There are too many cars on the roads now. A driver has to think of the other fellow and adjust his headlights so that he’ll get all the light he needs without blinding every- body he meets.” The car-owner smiled de- called out the young chap be- hind the driving wheel. ‘I’ve been tooting my horn out in Gus and Joe Save You Woe risively. “That sounds all right,” he said, “‘ but it just can’t be done.” front for the last five minutes.” ““Never heard you, son,” re- sponded Gus, while Joe hur- riedly wheeled the portable gas tank around behind the car. Gus stood surveying the car reflectively while the filling process was goingon. Then, as Joebegantoscrewthe cap onthe gas tank, Gus wiped his hands in a bit of waste and strolled over to the front of the car. “Say, young fellow,’’ he said, “why don’t you fix those head- lights? You’re due for a ticket if you leave them like that.” “What do you mean, ‘fix’? ” HIS is the second of a series of stories by Mr. Bunn, in which his two fascinating characters—Gus Wilson and Joe Clark, proprietors of the ‘‘Model Garage,” are giving you valuable tips from their long experience on how to run your car efficiently, safely, and with the least possible expense. If, by chance, you did not meet these two veteran automobile men in last month’s issue, this will intro- duce them to you. Gus, the mechanic of the combina- tion, tells you of the many little kinks that will save you trouble in the upkeep and operation of your car. Joe, his partner, the “figure man” of the firm, has a store of valuable suggestions on how to keep your motoring costs down. The advice that Gus and Joe will offer each month is of practical use to every automobile owner. Each article in the series will be a complete story in itself. However, if you failed to read Mr. Bunn’s first article in last month’s issue, in which Gus told how to put your demanded the owner indig- car in summer trim, it will pay you to go back and read nantly. ‘‘Those are darn good it. lights. See how they light up And you won’t want to miss next month’s article, in which Gus will explain little known yet invaluable tricks of gear shifting that will help you get the most satisfaction in driving your car.—THE EDITOR. your garage.” “Sure they’re good lights,” nodded Gus with a grin. ‘““Good for you, that is. But how about “It can’t, eh?’”’ snapped Gus. “IT wish you’d give me five minutes on those lights! If I can’t make better lights of them and still have them com- ply with the law, I’ll make you a present of my time—and throw in that gasoline you just bought!”’ “Fair enough!’ grinned the owner. ‘‘Go to it!” Wilson got a toolkit, stepped to the front of the car, and res moved the front flange and lens from each headlight. Then he took out the bulbs and examined them carefully, holding them up to the big electric light in the center of the garage ceiling. **There—see how much dark- er one of them is,” he said, offering them so that the owner might observe also. ‘“‘That’s caused by little pieces, or mole

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ugust, 1925 NIC, hem ‘lare rive fast.” on. “But the same, ht as you drove like ‘ouldn’t be ictims—or he wrecks! r with daz er. There snow. A fellow and e’ll get all ling every- miled de- right,” he ; be done.” pped Gus. » me five ights! If ' lights of hem com: make you Fime—and e you just ‘inned the it, stepped ir, and re- re and lens Then he lexamined ling them ie light in ige ceiling. auch dark- ’ he said, the owner “That’s 3, or mole- August, 1925 cules, or whatever you call ’em, that- fly off the hot fila- ment and stick to the glass. A few more days and this dark bulb will be ready to pass out for good.” ‘‘Phew, better a let me have a new one!’ exclaimed the owner. “In fact, you’d better make it two. They’ve been on the job more than six months now, and I do a lot of driving at night. Put in good big ones so I’ll have a lot of light.” “Nothmg stirring,’ said Gus; “21- candlepower is all the law allows you, and you have that size now. Of course, some of the ‘gyp’ dealers will sell you bulbs marked with a higher rating than 21-candlepower, but the extra candle- power is mostly in the label on the box!” “Twenty-one for me then—got two tickets for speeding this year and I cer- tainly don’t want another chance to say ‘Good morning, judge!’ ” “It wouldn’t be healthy for your pocketbook,” Gus chuckled. ‘Joe, get out two bulbs—make it three—you ought to have a spare.” HILE Joe went after the bulbs, Gus carefully dusted out the reflec- tors with a clean silk handkerchief that had appeared miraculously from a con- cealed pocket in his greasy overalls. “Speaking of reflectors,” said Gus, “‘one of those scientific sharps told me once that an automobile reflector that had lost enough of its shininess so that you could tell that it was not quite new would re- flect only about 50 per cent as much light as when it was new.”’ “Well,” the owner observed, ‘‘who’d expect a rusty old reflector to give much light?” “Who mentioned rusty junk?” de- manded Gus; “I meant a reflector that has lost its first brilliancy—just a bit foggy—not really bad at all. Take your reflectors. They look like new, but I’ll bet they’ve lost at least 10 per cent of their light-reflecting power.”’ “Well, what can I do about that?” asked the owner. “Nothing,’’ Gus answered. ‘Special buffing apparatus is needed to bring full polish back to a reflector, and it takes an expert to run the ap- paratus. The best way for the rest of us to treat a headlight reflector is to leave it alone. Anyway, never do more to it than dust it off as gently as you can every now and then. Then when the shine goes, after a year or two, send it to some firm that makes a specialty of refin- ishing auto lamps.” * [EAVING them alone ought to be easy enough,” laughed the owner; “but isn’t there any- thing I can do to keep them from getting dim?” “Yes. Have the front lenses fit as nearly airtight and water- tight as possible.” When Dazzling Lights May Spell Disaster iia This picture illustrates the danger of up-tilted headlights in blinding the other fellow on the road. The dazzling effect is increased when the car is going over the brow of a hill POPULAR SCIENCE MONTHLY ee os ‘“Why not use a rubber gasket in place of that piece of cord, then?” “Not on your life!’? Gus said emphat- ically. ‘‘ Don’t use rubber on any account. It would make a water-tight fit all right, but after a while the sulphur in the rubber would discolor the silver plating on the reflector. The cord will do the work well enough, provided it is not squashed down so that it does not have any spring left in it.” He fished a screwdriver out of the tool- kit, and fitted it to the screwhead that $10,000 F YOU have not yet en- tered our great ““What’s Wrong” Contest, turn to page 29 of this issue and read how you can win one or more of the cash prizes. projected from the center of the back of one of the headlights. ‘See what happens to the beam of light when I turn this screw,” he bade. ‘*Notice how it contracts and then spreads all over the door again. We will leave it where it makes a smooth, uniform band across the door. That happens to be an extra good bulb—nice, even light. It’s almost impossible to focus the cheap bulbs some of the ‘gyps’ sell you. “‘There!”’? Gus said as he tossed the screwdriver back in the toolkit after focusing both headlights properly. ‘‘ Now we'll see about turning those beams down so that they don’t hit the door Why a Spotlight Is Valuable It is when you are driving around a sharp curve at night, says Gus, that a spot- light helps to keep you from running somebody down. This picture shows why the driver without a spotlight cannot see persons walking ahead at a turn in the road 73 above the line.” He examined the lamp bracket care- fully. “This is going to be easy,” he said; “the brackets are adjustable, so all we have to do is to loosen up the bolts and set the head- lights where we want them. Joe, just hold your hand on the door there so I can see where the top of the beam ought to come —there, that’s right.” “But you have the lights pointed too low now,” complained the owner as Wilson tightened the last nut. “N°? THEY’RE just right. You have to make some allowance for the ef- fect of loading down the back end of the car with three people. You want them right when you have a full load of pas- sengers aboard.” “‘Gosh, I never thought of that,” said the owner after studying the light on the door for a moment. ‘‘They seem to give a pretty good light at that. Maybe I won’t have to dim them every time I pass another car now that they are on the right side of the law,’’ he suggested. “Not unless you are going over the top of a hill,” said Gus. ‘“‘That makes the beam shoot up in the air a bit. By the way, why don’t you fit a spotlight?” “What good would that do? The head- lights ought to be enough to drive by.” “They are,” said Gus, “except when you are going around a sharp curve. In that case a spotlight might help to keep you out of a ditch—or keep you from running somebody down. Besides, a spotlight is a big help in reading road signs at night and in turning the car around or backing into the garage. Of course, it ought to be mounted so that you can throw the beam backward. Spotlights are all right—if you don’t use them so that you are a nuisance to every one else on the road.” “GOME people do,” said the owner. “I passed a fellow like that last night. He nearly blinded me and then tried to push me off the road in the bargain. However, I think you’re right about the good points of a spotlight. If I had one it probably would help me in getting into my own garage. Got any good ones in stock?” “Sure, some dandies,’’ Joe Clark broke in, instantly alert for anything that might help jangle the cash register. The customer consulted his watch. “T can’t stop long enough to let you fit one now,” he said; “but I’ll be in tomorrow—sure. Here, take out for everything,” he instructed Gus, handing him abill. “A fellow can learn some- thing new about his car every day,” hemurmuredthoughtfully. “‘He can—and he ought to,” responded Gus. “I’ve had 20 years of it, and I’m. still learning.”

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Simple Jobs Any Motorist Can Tackle Here Are Handy Kinks required to get the last few inches of bead over the edge of a clincher rim, especially if the tire is new and stiff. The simple arrangement of boards and a piece of rope shown in Fig. 1 will enable you to apply pressure enough to mount the stiffest tire with ease. If you want to make a permanent job, the shorter piece of board that rests against the tire can be attached to the upper board by means of an ordinary strap hinge. () seasired to eet pressure often is iB AN electric drill is available, an easily made wire scratch brush will make carbon-removal jobs exceedingly simple and speedy. , Fine steel wire is roHed into a coil about 4 inches in diameter and one side of the coil is bound tightly with brass wire as shown in Fig. 2. Then the coil is cut at the side opposite the binding and the bound portion is forced into the end of a piece of brass tubing attached to a shank that will fit into the drill chuck. Alittlesoldering fluxis dropped into the end, and when hot solder is poured in and allowed to cool, the wire is anchored firmly. If hard steel wire is used, the brush will last for a long time. SMALL amount of the ini- tial valve-spring tension is lost through repeated facing of the valve and valve seat. There are two ways to remedy this trouble. One is to stretch the springs, but this method does not always work, because springs that are stretched tend to get back to their original length after they have been in use for a short time. Another way to increase the tension of the valve springs is to place washers at the upper or lower ends of the springs as shown in Fig. 3. The upper position is preferable because it does not add to the moving weight. Be careful to see that the washers seat squarely, for if one side is cocked up, the resulting side pressure of the valve spring will cause exces- sive wear on the valve guide. N FIG. 4 is shown a good way to make a universal wheel puller that will work on any auto wheel regardless of the dimen- sions of the threaded por- tion. The shell of the wheel puller is made of 4-inch extra heavy iron pipe. A piece of ¥-inch flat steel is fitted into one end and welded Fig. 6—Friction tape will help to cut down fan-belt troubles if properly applied CYLINDER HEAD Fig. 2—This electrically driven scratch brush of simple construction makes carbon removal an easy task POPULAR SCIENCE MONTHLY Fig. 1—Giant ‘‘nutcracker”’ is great help in mounting a stiff new tire on the clincher type of rim ELECTRIC Fig. 4—This homemade. universal wheel puller will remove the rear wheel from a car of any make Fig. 5—Running the car up an incline, and jacking the front wheels simplify the job of drawing oil from crankcase into place. A 18/16-inch hole is drilled in the center of this plate and a %-inch S. A. E. nut welded to the plate at the inside end of the hole. At the other end of the pipe, six holes are drilled and threaded for %4-inch S. A. E. cap screws. The wheel puller is used by tightening the six screws against the wheel hub as shown in the illustration. Fig. 3—Where washers are inserted to increase tension of valve springs August, 1925 to Make Work Easter When pressure is applied to the center of the axle by means of the long center screw the threaded flange prevents the wheel puller from sliding off, and the tightest wheel can be removed. 6 Base man who takes pride in his auto mobile makes a practice of draining the crankcase about every 500 miles, This is a messy job at best, but it wil] make the work easier and the draining more thorough if the front of the car ig run up the incline to the garage as shown in Fig. 5. If the incline to the garage is not great enough, then it will be worth while to jack up the front of the car as indicated, This will make it much easier to get at the drain plug with a wrench, and tipping the motor will drain out the oil in the splash pockets under the connecting rods. Another advantage is that the oil can be run directly into a regular bucket rather than into the shallow pan that often is necessary because of lack of clearance under the _ crank- case. jew fan belts frequently give trouble through slip ping or coming off the pulley. Both these troubles often can be eliminated by winding tape around the center of the pulley so that the center is larger in diameter than it is nearer the edges. The belt then will have a tendency to run on the center of the pulley and the tape will cut down the slipping. Another advantage is that if the belt runs squarely on the center of the pulley, it will not wear away the rim or the flange. I" IS easy to make a set of wooden jacks that will keep tires off the floor. The jack illustrated in Fig. 7 is designed on the “knuckle joint” principle, using an ordinary strap hinge as a knuckle. A 4-by-4-inch block serves as a base, held to the lower member by spikes. To prevent the length of 34-inch pipe, used as a detachable handle, from hitting the hub cap when the jack is raised, a space block is attached to the front of the lower member. The jack is shoved under the wheel, back of the hub cap, as shown in the il- lustration. Then the pipe handle is inserted in the hole and the top end of it pushed toward the car, and the wheel is raised to height desired. Fig. 7—Simple jack to keep tires off the grounu when the car is stored

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gust, 1925 Kle aster center of ter screw, she wheel 2 tightest by: auto. draini 00 mila ut it will - draining che’ car ig as shown not great 1 while to indicated, to get at nd tipping n out the cets under re is that ‘ectly into ther than that often of lack of ie crank- frequently ough slip- he pulley. often can iding tape the pulley ; larger in nearer the 1 will have ter of the down the is that if center of ly the rim »den jacks oor. s designed ple, using uckle. A se, held to ‘o prevent ised as a g the hub

POPULAR SCIENCE MONTHLY August, 1925 75

Sa — ere

er~ "Home Worksho Arthur Wakeling, Editor

Small Girls and Boys Built like a Real House with Ample Space for Toy Furniture HILDREN never seem to become Such a house, if carefully C built, neatly lined with fiber wallboard, and well painted, helps to solve the difficult problem of keeping the chil- dren from wandering away from their own yard, perhaps to play in streets ever be- coming more hazardous with the traffic of autos and heavy trucks. Details for the construction of an espe- cially realistic and substantial playhouse

‘tired of.playing house, even if they have nothing more than the back porch or a discarded table to represent the house. But their joy in this old play- time stand-by is far greater if they can have a miniature house of their own, large enough for them to enter, with real doors and windows—a house that will hold their tiny furniture, their toy kitchen range and dishes, and all their big family of dolls.

SHINGLES LAID 4° TO THE WEATHER

RAFTER FACING 7B x4" 8-4)"

a == = h<—————. 6-2" RAFTERS 2°%4°%4-4" s— STUD 2x3 %4- - Six 5 ates Yyff CENTER JOINT Pi CEILING JOISTS BFA 4agH- BHA Vig MYM NN l; 2°x4"x6-0" SY, Zefory Z YW Wg Y yey Yr SA NAN WINDOWS ¢ ttf; Vi Bey jeg Y Y, < Vp Y, SN A fF MATA Zi ‘A ATU A WiL...—| i----4 on Lt ae { ith | i ! Ny aa | ee geal DOvBLED SSC hl all SILL ME it (ha || | ee | . i i N\|2% xO x3-3 ei oT WE +4 tj ti ti iF rt 1} i AUT ye i. li) aa | ee | | a|\ =| Shap Ml 79 AE HLA | Situs Me | Ain I | 1 Sn | Hist i | gi | tl m=] UT | | qin || ee) | | a | xO x22 FLOOR JOISTS u EZ Oye ree CORNER BOARDS 7% THICK x0x6-0 a SILL2 x4 Front and side elevations of the playhouse broken away to show the wall, floor, window, and roof construction; the method of framing and details of the casement windows at front and back, the door, and the water table

are given in the drawings below. designed by George F. Kaercher of Phila- delphia, a

It was recognized authority on woodwork, who is known to readers of POPULAR SCIENCE MONTHLY through his contribu- tions to the Home Workshop series of blueprints. The house is 6 ft. 2 in. wide, 8 ft. 2 in. long, 8 ft. 414 in. high to the top of the roof, and 5 ft. 6 in. high from floor to ceiling. It has a door and a double casement window in the front, another casement window in the back, and two fixed windows on each side. There are also two small ornamental upper windows in front and back. While the use of so many small windows makes the house seem more like a real building, consider- able work can be saved by reducing their number. A door and casement window in the front and one fixed sash in each side will serve. The sash can be purchased ready- made from your lumber dealer, and it is well to find out what stock sizes he has on hand so that you can make the framework to suit. The casement sash, which are, of course, hinged, can open either in or out. The children prefer to have them open in, but it is easier to make them water-tight if they are hung so as to open out. It is possible, too, that you can obtain a cupboard door that will serve for the front door, if well painted. It is a simple matter, (Continued on page 101) HIS month’s Home Workshop Department will be found on pages 75 to 80 and 85 to 101, The Shipshape Home on page 84, and The Better Shop Methods Depart- ment on pages 82 and 102 to 108.

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76 Upholstering the “Hard Edge” Way How This Simple Method Is Applied to a Stool or Seat called “‘hard edge”’ type of upholster- ing gives a comfortable seat. An example of this simple method of up- holstery is the footstool illustrated, which also might serve as a fireside seat. Many old-fashioned chairs, as well as some of the later styles, have seats with a hard edge. You are apt occasionally to have to repair a chair of this kind. That will prove a simple matter if you will con- struct the stool shown or even if you do nothing more than study the illustrations and the following suggestions carefully enough to learn the distinguishing points of this class of upholstery. Any soft wood will serve for the Geille“ as it may sound, the so-

POPULAR SCIENCE MONTHLY By William T. Weld Shopwork Instructor Central High School, Peoria, Ill. wooden framework

Fig. 1—The finished footstool (above) and the details of the (below )

August, 1923 illustrated in Fig. 5. The knot (cloy hitch) used for tying springs was de. scribed in the May issue of POPULAR §¢j. ENCE MONTHLY (page 104). The twine is fastened with 12-o0z. tacks. After the springs are tied, a piece of heavy burlap is placed over them ang tacked along the edge of the rails where the wood has been rabbeted out as shown in the drawing (Fig. 1). Upon this by. lap is placed the stuffing. Flax tow may be used and for a seat of this size about 4 or 5 lbs. will be needed. Pick oy any hard lumps and spread it evenly over the seat, allowing about 2% or 3 in. of it to protrude beyond the seat frame. Keep the surface of

rails of the stool (Fig. 1), as they pom ee RABBETED RAILS eee NER RAE the stuffing reasonably level and the are covered, but the four legs, the "x 1%"¥ 20" h>| one. Ne =f edges well filled out. two lower end fails and the fii Ni Over this is laid a piece of lighter. stretcher should be made of a Mer SPACE /e- » STRETCHER weight burlap. The stuffing is hard wood such as oak or walnut. 2 eee. _ pushed in along the edge and the Casters may be inserted in the » wg 4 ALL TENONS { 7 } burlap is slip-tacked to the frame, legs, if desired. All the wood- Wag X3 x19°% “8 THICK T | By slip-tacking is meant driving work and the finishing should be e —— = Ih = == 5 = SJ] tacks only partway in so that they done before commencing the up- i SS ee ES /| may be removed easily as the burlap holstering. if i > Ae % X%x3"x 14% [| Gs drawn down over the stuffing As they appear in Fig. 2, from |/ Le LEGS 12X12 x14 ‘we vr ‘| while it is being worked into posi- left to right, are the following |/ “st _ | Tt. /| tion. Use a stuffing regulator to necessary tools and supplies: sheet se ‘ er { ee == | || ‘work the tow whenever the proper | SS | IS Ss wadding, box of gimp tacks, a roll TAPERED ON INSIDE? 3 1 Gee ait |/) shape of the edge cannot be secured of gimp, springs, spring twine, | ]_-10 1%'x1%'AT BOTTOM "0 | /} ~4XV2Xx || by working along the edges. webbing stretcher, curved needles, | 1-9" "+4" When the burlap has been slip-

double-pointed needles, stuffing regulator, hammer, shears, webbing, and kapok for stuffing. In an article of this series published last October in POPULAR SCIENCE MONTHLY (page 86) it was explained in detail how to attach the webbing and stretch it into

place. Figures 3 and 4 show how the seat appears when the webbing is tacked in place and the springs sewed to it. The springs used in this seat are size No. 3,5% in. across. The webbing is 3) in. wide. How the springs are tied in place is Fig. 3—After the web- bing has been stretched and tacked across the bottom, the springs are put in place and held with long stitches — <=" _—— - —, a se

Fig. 2—The tools, webbing, stuffing, gimp, wadding, springs, twine, and other supplies needed for hard-edge upholstering, all of which are relatively inexpensive Al

tacked along the edges, it is well to take several rows of stitches with the double-pointed needle through the two thicknesses of burlap and the tow. These stitches should be 2 or 3 in. long and the outer row should come just outside the outer edge of the springs. Be careful in (Continued on page 97)

Fig. 4—The bottom of the stool, showing the webbing and the stitches that hold the springs

Fig. 5—The springs are tied down with lengths of twine, the ends of which are tacked very securely to the frame Fig. 6—The stuffing, covered with burlap, is sewed to form an erect edge

Fig. 7—The center is filled with stuffing and covered with wadding and muslin

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knot (clove 2S Was de. JPULAR §cy. The twine a piece of them and rails where ut as shown on. this bur- ax tow may S size about Pick out ad it evenly ' about 2, beyond the surface of vel and the e of lighter. stuffing jg ge and the the frame, ant driving o that they s the burlap she stuffing 1 into posi- -egulator to the proper ; be secured ges. s been slip- it is well to es with the gh the two tow. These ong and the outside the e careful in lowing the the springs ith stuffing ind muslin POPULAR SCIENCE MONTHLY August, 1925 what I call the piece of furniture il- lustrated in the accompanying pho- tographs. It just has been completed and was inspired by the many useful inno- vations built by contributors to POPULAR A" ELECTRIC dining cabinet is ‘ proved useful to the writer. Branch of Tree Serves as Garden-Tool Rack PADING, hoeing, raking, digging, and miscellaneous chores of the amateur gardener require the intermittent use of various gardening tools. For keeping the tools handy, the device illustrated has A long, stout branch or a small, scrub tree, pointed at the lower end, is thrust into the ground within convenient reach. An old Christ- mas tree serves well for this purpose.— A. E. ZIPPRICH, New York. Trail Markers for Hikers SQ x ws \ SY How the hiker sights the next trail marker \ v OCK markers consisting of two long stones laid close together with a flat stone over the top are excellent guides for campers and hikers. They are used like agunsight. The hiker looks through the hole, or over the top of the flat stone, in the direction pointed out, and sees the next signboard or marker at the point where the trail enters the woods ahead. On wide open spaces, two or three of these sighting points may be placed in succession.—ARMSTRONG PERRY. 77 An Electrified Dining Cabinet Serves as kitchenette, table, and cupboard, yet looks like a fine cabinet when closed By Martin H. Ellingson is supported on a hinged framework, as shown, to form a dining shelf. The case is stained a moss green and waxed. So that it can be moved easily and noiselessly, it is mounted on heavy ball-bearing casters. Electric outlets for attaching such cook- SCIENCE MONTHLY and described in your past issues. For any one with limited room in his home, a more useful article of furniture hardly could be con- structed. It provides a complete electric kitchenette with din- ing shelf attached, and has ample store- room for food, uten- sils, and dishes. When ing appliances as the coffee percolator, toaster, chafing-dish, and stove are con- nected by concealed wiring with an outlet on the outside of the cabinet near the bot- tom, and this in turn is connected with an electric cord to a con- venient base or floor outlet whenever a meal is to be prepared. An electric lamp aiso is included in the permanent wiring of the cabinet. not in use for cooking or dining, it can be closed completely and pushed against the wall, where it has every appearance of being a fine piece of living- room furniture. When closed the cabinet measures 4 ft. long, 4 ft. high, and 17 in. deep. It is built from 3-ply veneer panels and odd lengths of old oak molding. The front panel is removed bodily to open the cabi- net and half of the back drops down and Three views of the cabinet, showing dining shelf, the electric equipment and storage compartment, and as it appears when closed This contribution was submitted in POPULAR SCIENCE MONTHLY’S recent Photo Handicraft Contest and was given honorable mention by the judges. If you have followed withinterest this and other Home Workshop contests, do not overlook the great $10,000 contest announced on pages 29-31. Anyone who reads this department attentively should have no difficulty in telling what John is doing wrong in each of the puzzle pictures. Simply Made Iceless Cooler Preserves ‘Campers’ Food [itso for campers’ food is what is known as an “Arizona ice-box.” A frame is constructed as shown and covered with galvanized-iron netting, which runs 4 or 5 in. above the top. The outside netting is covered with two thicknesses of burlap and a tin pan is made to fit in the space on top of the box. The box should be suspended by wires or ropes from a tree or scaffolding. About two dozen strips of flannel, 2 in. wide and long enough to reach from the bottom of the water-pan on the inside to about 3 in. down from the top on the outside, are arranged in the pan as indicated. When saturated, the strips transmit the water to the burlap, where it spreads over the FLANNEL WICK 2" WIDE surface of the entire box. The evapora- tion of this moisture absorbs the heat in the box and in dry, hot weather keeps milk or butter equally as well as ice does. If the water seems to evaporate too rapidly and leaves the lower surface dry, put on another covering of burlap. A handy arrangement is to keep the box near a faucet and let the water continually _ drip into the pan.—E. G. G. Finds Blueprints Helpful I NOW am building a tea-wagon from one of your blueprints. They sure are a big help to any one who has a home workshop. As soon as I ”—* this done I’m

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78 POPULAR SCIENCE MONTHLY August, 1995 Home Workers Show Their Skill Prize Contest Photos Offer Many Suggestions for Craftsmen making those new doors for the kitchen cupboard or building that long contemplated radio cabinet because the task seems a difficult one, take courage and inspiration from the photographs below. They show the best product of other home workers who, perhaps like yourself, began with only a small equip- ment of tools. What can be accomplished in the way of making useful and beautiful objects I: YOU have been hesitating about Library Table Built by William Buehler, St. Louis, Mo. Contains 144 pieces of four woods. The top is 20 by 44 in., with three stars of mahog- any and maple inlaid in walnut, and placed in a double border of mahogany and holly in the home never was illustrated better than in POPULAR SCIENCE MONTHLY’S With the exception of the prize-winning con- tributions published last month, these photos were the best received and were recent Handicraft Photo Contest. awarded honorable mention. There seems to be an especial fascina- tion in building inlaid tables. tables illustrated on this page. The phonograph is unusual because of the use of a violin as a sound chamber to The ship model has the distinction of being only 31 in. long, although complete to the last degree. improve the tone. serjete wMeMehetiet Inlaid Table Has 44,171 Pieces Twenty varieties of wood were used by John Wharton, of Dayton, Ohio, in carrying out the color scheme of this table, which was built with ordinary hand tools. iio ate Miniature Ship Model A miniature ship built with penknife and darning needle by Douglas H. Burt of Indianapolis, Ind. A “Violagraph’”’ Built by Charles H. Fer- nald, of Malden, Mass. When not in use, the violin sounding device is lowered by turning the crank and is completely concealed by the cover Lighting Fixtures Hand carved wooden candicstick and two table lamps made by William Buehler, who constructed the library table above Five years were required in its construction Each block is roved correctly and there ig a man at the wheel and a lookout on the forecastle. The candlestick holder and table lamps are carved from wood and beautifully finished. The candle is silver and blye with a base of old-gold color stippled in polychrome. The lamp stands also are in Many polychrome over gold. excellent examples were received, among the most elaborate of which are the four Eight months’ spare time was required in making the model of the moon, A chart with key numbers is used to locate the 700 principal features. Six Years’ Work This table, which contains 20,505 pieces, more than 18,000 of which are in the top surface, was built by W. W. Flanigan, engineer at the Branch Agricultural College of Utah, Cedar City, Utah. Ninety-one varieties of wood were used and the work took six years in all Pedestal Tabie A pedestal table madc entirely by hand by H. F. Burt of Wichita, Kans. It has 6516 pieces of 18 different woods. The largest pieces are only % in. wide; the smallest, 1/32 in. wide. The top is 20) in. square and the table stands 27 in. high. Mr. Burt spent a few hours a week for six years in assembling and finishing it Model of the Moon Plaster-of-Paris model of the moon 12 in. indiameter. It was made by Herbert B. Collier of Viking, Alberta, Can.

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1eust, 1925 “ill on id there jg Ut On the ible lamps eautifully and blue tippled in also are in S required noon, A L to locate ieces, more op surface, neer at the tah, Cedar s of wood ears in all . - Table 1adc entirely F. Burt of It has 6516 rent woods. , are only % lest, 1/32 in. is 20% in le stands 27 urt spent a for six years finishing it 2 Moon 1odel of the ilameter. It derbert B. \Iberta, Can, August, 1925 POPULAR SCIENCE MONTHLY 79 How to Give Furniture a Beautiful Finish ane NITURE rise he jOHNSON shewnod FIAT RU Ys m The Johnson Book gives complete instructions for finishing new and refinishing old wood— softor hard. This book ts the work of experis —beautifully illustrated in color. Ask for a free copy at your best patnt or hardware store. Stores displaying the above sign carry a full line of Johnson’s Artistic Interior Finishes. They will give you a free copy of the John- son 25c Book on Home Beautifying and are competent to answer questions and give advice on the proper finishing of wood. These stores will gladly show you panels of wood finished tn many beautiful effects. For a blue print of this attractive combination Book Rack and End Table send us 25c in coin or stamps. FTER spending precious hours making furniture by hand you naturally want to give it a beautiful finish. And surely the fin- ishing should receive its share of attention, for a beautiful piece of furniture may be ruined if improperly finished, whereas any small defects are minimized in a well-finished piece. So the finishing of your furniture becomes a matter of prime importance. First apply a coat of Johnson’s Wood Dye. With this you can color the wood any one of 17 beautiful shades. John- son’s Wood Dye is very easy to apply —it dries in four hours and will not rub off or smudge. Penetrates deeply, bringing out the beauty of the grain without raising it. Open grained woods (oak, chestnut, ash, mahogany, walnut, etc.,) should then be given a coat of Johnson’s Paste Wood Filler followed by a light coat of Johnson’s Under-Lac or pure white shellac. The furniture is then ready to be finished —either with two coats of Johnson’s Prepared Wax or Johnson’s Varnish. For close grained woods (pine, cypress, maple, birch, etc.), omit the Filler coat. Follow these instructions for fin- ishing furniture and you will be assured of perfect results—the thrill of pleas- ure when the work is new and yearly satisfaction at its wearing qualities. S. C. JOHNSON & SON, “‘The Wood Finishing Authorities’? RACINE,WIS. JOHNSON’S WOOD DYE IS} This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17.

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POPULAR SCIENCE MONTHLY August, 1995 | Glider Adds Zest to Swimming Skims Over the Water — like a Hydroplane AWN) By Donald W. Clark Augut This speedy water glider fur nishes rare sport for the sum. ae. “1 FIN mer camp. ‘The swimmer | FRONT eS ELEVATION _ ~e se eo _| WHITE —— ; HOLETOFEED - psa] LL __, 942 x34 STRAP IRON. 2, vg | {AIR TOSTEP fl \ shoots down the 40-deg. incline and skims over the water steering himself by operating the rudder with his feet. When the glider loses speed, it no longer supports the rider and sinks below the surface. The rider then swims to shore, tow. ing the glider, and, placing it under his arm, climbs the steps ready for another “skim,” The incline is built mainly of 2 | by 4’s and 1 by 4’s. The glider itself, which is fully de. tailed, should be well painted and varnished. A long, canvas-covered cushion should be made to fit the glider and fastened in place with straps — 12> oe H , SAS e4 é f oe 3 a FRONT-WHEEL FRAME PLATE EDGE ROUNDED Washstand, Oven, and Frying-Pan for Camp | pecially appreci- ate a good stand for the wash-ba- sin. By utilizing the materials of nature as shown at the left, a washstand can be made right for an oven. Provided it has ears nd wire handle, a pail makes a good oven. About halfway down, punch four 34-in. holes in it, bend two cross wires as shown, and spring them in place. These make a shelf for supporting a pan of biscuit or other camp bread while baking. Make a tin cover to fit the pail and punch a number of 34-in. holes in it. Hang the oven by means of a wire or small chain from the cross bar of the camp fire, or place it directly over the coals. A pair of square frying-pans may bemade from two ten-cent sheet- iron baking-tins about 2 by 8 by 10 in.insize. Punch two l¥-in. holesin one of the longer sides of each tinas shown, about 3 in. from the ends. ast! EI on the spot. came . Cut aslot 2 in. R Cut down three ee ; long in the é i largesaplings and same side di- E trim them all to SRE SHELF rectly beneath yee about 5 ft. —. the edge wire. ba The slots al- we so the butt in- iar al. pt > BS PD 5 : cludesonebranch Sa om ash-basin su rte by three beshehes ylang = angle indicated. Remove these off- shoots about 6 in. from the trunk and then turn the resulting sticks upside down so the butts and crotches are RUBBER BANDS MADE FROM INNER TUBE Frying-pans made of baking-tins low the wire handle to be sia pp ed through be- fore the bent ends are inserted in the holes. One of the pans can be used for heating water uppermost and the _ shortened pranchespoint in. Drive the stakes into the ground until the butts stand about 30 in. above it and equal distances apart. a is never any necessity for unpalatable food in camp through lack of cooking utensils. Even bak- ing can be done successfully with nothing more than an old water-pail “76 7 : * i, Wh An old water-pail with wire shelf and perforated tin cover forms an excelient oven for camp baking if the two are not needed for frying. Baking can be done by placing one pan on top of the other. Placed face to face, held together by rubber bands made from an old automobile inner tube, and slipped into a close-fitting canvas bag, these pans form a good size container for supplies. They will hold their own handles and some utensils, as well a8 the less bulky eating supplies.

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St, 1925 | August, 1925 ig OU can still buy a hand saw that is the personal product of a craftsman’s hands—and in which you can take a crafts- man’s pride. Though the world’s greatest saw works is alive with modern ma- chines— many of them invented and built here in the Disston plant— The fame of ‘“The Saw Most Carpenters Use’’ rests square on the skill of the Disston workman. The Disston Hand Saw seems alive as you use it. Perfect balance is the secret of its easy thrust and swing. Only Disston workmanship balances a saw that way. The Disston Saw follows true on the line. The skill of a Disston saw-maker made it true. It holds its cutting edge. Disston POPULAR SCIENCE MONTHLY their pride in this Saw workmen made the steel in that keen blade, hardened and temp- ered, set and sharpened it. Henry Disston’s first saws won their way on workmanship. And so, when your Disston Saw makes hard work easy, you are getting a result that generations have worked to give. What to expect of your Disston The springy, tempered Disston Steel blade that holds its keen edge so long— The true, clean, easy cutting that is so quickly done — The balance and swing that make it seem as a part of your arm— These are the things that Disston saw-makers, aided by improved methods and modern machinery, work into the Disston Saw. Go to the nearest hardware store. Take a Disston Saw in your hand. Read the promise etched on its shining blade. Test that promise in use. Try this saw on hard wood or soft, rough or fine work, for speed, ease and clean cutting. Then you will understand and share the pride of the men who make the Disston Saw! Ask Disston Tell us what kind of work you are doing, in wood, metal, stone, ivory, rubber, leather, cloth, fibre or other material, and we will tell you how to saw it better and easier. Disston issues many books to aid the user of saws and tools, Henry Disston & Sons, Inc. Philadelphia, U.S. A. © Hardware dealers the world around sell Disston Saws, Tools, and Files DISSTON © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17.

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82 POPULAR SCIENCE MONTHLY Aug’ Better Shop Methods, {| ow Expert Mechanics Save Sime and Labor Old Bill Babbitts a Bearing 5 ERE is a nice piece of work,” By James Ellis H Old Bill said to Bob Laten, point- Machine-Shop Superintendent | ing to a blueprint. ‘“‘The casting ¥ came in from the foundry this morning.” : “‘T wondered what it was,’’ Laten re- - | sponded. ‘It is to be fastened to the old bracket * 6 over by the door,” Old Bill con- the shop was a forge that Old Bill useq for melting babbitt. Near by was 4 planed surface plate. In a rack arranged according to sizes were a number of shafts used for babbitting mandrels. Laten brought the castings back and laid them on the plate, tinued. ‘“Let’s go and look at : He selected two of the shafts both pieces. ; i€ ~ both 1 15/16in. The longer of “Now, you see,” Old Bill said, af : the two he put through the begr. pointing to the details on the drawing, “‘this new casting is to og be bolted to the old one so that pnb . ad they will make a frame for a pair Ge 6 of miter gears. The customer did not send the gears, so you will have to locate the center lines ings in the original bracket. The shorter one he put in the new casting. He blocked up the cast. ings so that the bearing he wasto pour was vertical. Then he started to melt some babbitt. He found a set collar to put.on accurately.” the mandrel he was using. Then, Laten was looking at the new with a small square he adjusted casting. the shafts so that they were ex- “It will be hard to hold this in the shaper,” he suggested. “It EL will be so far up from the vise that I will not be able to make much time on it.” actly square with each other. It was simple to get them in line, for they were both the same size, The customer, looking on ap- provingly, said to Old Bill, who © Jf As Old Bill and the customer looked on, La- ten poured the Old Bill studied the casting. “T think it would be best to do the shaper work on a lathe,” Old Bill said. ““You can chuck the casting by the round hub and square up everything from the face of the chuck, then face off the ends.”’ Laten nodded assent. “T can face off the thrust bearing for the gear at the same setting,’”’ he said. It was some time after lunch when Old Bill next saw the job. “IT don’t know what they are there for,’”’ Laten remarked, pointing to the two setscrews on each side of the new casting, “but I am putting them in.” “The designer had you in mind when he drew them,’’ Old Bill said. . HE easiest way to get this drilling done is to drill and tap those setscrew holes first and put in the screws. Then you can put the new casting on the old one and hold it with the screws. Drill all the other holes. Use a 17/32-in. drill for the stud holes, drilling them through both castings, and ream out the old cast- ing to fit the studs. Then drill the bolt holes and the oil hole.” Old Bill looked at his watch. ‘‘ Make the best time you can on this job, Bob,” he added. “I got the job because I made the lowest price. I think I allowed four hours for all the machine work.”’ The customer for whom Old Bill was doing this work came in to see how it was getting along. A young man, but Old Bill had found him to be full of mechani- cal sense, and liked to hear him talk about his problems. ‘Looks as though you will have it done bearing for me in the morning,” he commented. “TI shall have it before thenif noth- ing happens,”’ Old Bill replied. ‘“‘A very important thing is to get the shafts at right angles,’”’ said the man. Old Bill smiled. He realized why he was being told something he knew. Old Bill himself constantly told his men things that they should know already. He was aware that men forget the little details just at the most important time. “We will babbitt this in about half an hour,” Old Bill said. ‘‘Stay around and see if we do it to your satisfaction.” The customer waited. In the back of Li i 5¢"BOLTS / The new casting and old bracket as assembled to form a frame for miter gears, and method of hold- ing the new cast- ing for machining FACING THE CASTING metal had just approached: ““You seem to happen around whenever anything important is going on.” ‘“‘ Well, that is one of the things that | am supposed to do,’ Old Bill replied, “IT get the blame if it is not right, so I try not to be blamed.” The set-up was finished. Laten useda putty made of asbestos and oil to prevent the molten metal from running out. Old Bill explained that it would not sputter and blow as plain mud would. “* ANOTHER little trick that may be useful to you some time is a method of pouring babbitt in wet places,” he continued. ‘‘A few days ago we were making some repairs to a concrete mixer that had burned out a bearing. It was out in the open and rain was falling. Of course there was water in the box, but we poured it without having the steam blow out all the babbitt.’”’ ‘IT suppose you put a shelter over the box and dried it out,’”’ the customer said. “‘Nothing of the sort,’’ Old Bill replied. ‘We filled the box full of oil and then poured the babbitt in on top of the oil. The oil floated out, and there was no steam, even though rain was falling.” Laten, in pouring the bearing, ran in enough so that he could chip it off flush. “Send it to me as soon as it is ready,” said the customer. Old Bill smiled. He knew the job would be _ satisfactory. ANY time-saving shop ideas are contained in the continuation of the Better Shop Methods Department, which you will find on pages 102 to 108.

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ill used was a rranged number bbitting castings he plate, Shafts, onger of she bear. et. The the new she cast- 1€ was to "hen he abbitt. 0 put.on r. Then, adjusted were ex- ther. It 1 in line, ame size, 1Z ON ap- Bill, who whenever 9 s that I _ replied. ght, so I 2n used a > prevent out. Old t sputter , may be me is a t places,” we were ete mixer . It was lling. Of box, but she steam - over the ymer said. ill replied. and then of the oil. e was no ; falling.” ag, ran in ; off flush. is ready,” liled. He tisfactory. ideas are uation of partment, 102 to 108. POPULAR SCIENCE MONTHLY Why Does the Borrower Always Ask for Starrett Combination Set No. 9 Layout — Checking— General Shop Work— actually, the uses of this splendid kit of tools are limited only by the ingenuity of its owner. Taking up but little room on the bench or in the tool box, the Starrett Combination is a universal favorite with Ma- chinists, Carpenters, Auto-Re- pairmen and Mechanics of all sorts. Three attachments: Head, Pro- tractor and Center Head slide freely on the Blade. They can be instantly clamped there in any 8084 THE L.S. STARRETT CO, World’s Greatest Toolmakers Manufacturers of Hacksaws Unexcelled Steel Tapes—Standard for Accuracy ATHOL, MASS. position or entirely removed. The Set gives you the use of a Rule, Try Square, Depth Gage, Height Gage, Level and Plumb, Marking Gage (note Scriber held frictionally in. Head), Center Head and Protractor. Blade is hardened and graduated in either 64ths, 32nds, 16ths and jj 8ths or 64ths, 32nds, 16ths and 100ths, as desired. All parts well made and warranted accurate as you’d expect in any Starrett Tool. Sold by good hardware stores everywhere, Over 25 different sets which can be made up with Starrett Combination Squares and Attachments are described in the Starrett Catalog of 2200 Fine Precision Tools. The ~ Catalog will help you select the Set best suited to the ree quirements of your work., Mailed free. Ask for No.23W © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17.

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POPULAR SCIENCE MONTHLY August, 1925 The Home Shipshape ADJUSTMENT for windows in the cellar, garage, or motorboat, can be provided easily and cheaply as shown below. If the window is hinged at the bottom, a nail is driven into the edge of the sash, and a piece of safety or plumber’s Simple Win- dow Adjuster chain is fastened to the frame with a screw. If the sash is hinged at the top, the chain is fastened to a floor beam or to the ceiling above the window. The desired opening is maintained merely by hooking a link of the chain over the nail. —J. F, HARDECKER, Brooklawn, N. J. ~ : SHAVE 1 lb. of Cleaning Paint | \hite sn aed and Enamel melt in 3 qts. of hot water. Addi oz. powdered borax, and let the whole sim- mer, stirring now and then, until the soap and borax are quite dissolved. Wash the painted surface with a flannel cloth with this preparation, cleaning off with clear warm water. To clean enameled surfaces, first dust off and rub with a soft rag wrung out of hot water and dipped in the finest whit- ing, or, better still, precipitated chalk, as the latter is less likely to cause scratches. I KEEPING your Your Brace home shipshape and Bits you find frequent use for brace and bits. If you do not own a brace or have only a cheap one, it will pay you to get a good brace with a ratchet attachment. A wide sweep is not necessary for ordinary work, but the tool should be of the best quality. Learn to use the ratchet freely; it is a great saver of strength. When well oiled, a slight motion of finger and thumb turns it on to left, right, or off. For corners and all awkward places it is invaluable. For giving the final turn to screws, and for drilling with large bits, it allows you to exert ample strength with the least effort. Indeed, it makes a small brace a very powerful tool. It is well worth practising tothrowit on and off. When much work is done, it is well to an Adjusting cellar sash— Painting kinks—Chim- ney repairs —Trousers’ rack—Brace and _ bits a have two braces. One need not be as expensive as the other. The countersink bit is kept in the cheaper one, or, if you are working on hard wood, where two bits are required for making screw holes (one the size of the shank of the screw being used and.the other to suit the twist), you avoid constantly having to change bits or drills—A. E. ELLING. WHEN a brick How to Clean | mantel or chim- ney place becomes Stained Brick stained with soot or smoke, the discoloration usually can be removed. Take 1 gal. of soft soap, 1 lb. liquid ammonia, and 2 or 3 lbs. finely pulverized pumice-stone. Mix to the consistency of ordinary oil paint and apply to the stain with a fiber brush. In half an hour rub the place well with a fiber scrub brush. The lather made by the process may be removed with water and sponge. It may be necessary to repeat this operation. Should the trouble persist, it will be necessary to give the brickwork a very thin coat of paint made from Venetian- red ground in oil, thinned with turpentine. If a lighter color is required, add some yellow ochre; if a darker color, add a little blue.—A. ASHMUN KELLY. So SMALL is the Hanger for usual clothes- Trousers closet that it is well named a clothes-press. Any closet space-saving device is, therefore, an aid in keeping a house shipshape. The trousers hanger illustrated can be made to hold four or more pairs of trousers. It hangs on the inside of the closet door. The loose rods are cut from old brass cur- tain rods or %-in. wooden dowels. When the hanger frame is “let down,” it takes but a moment to slip a rod through the doubled-over legs of a pair of trousers and replace it.—F. S. Root, Fall River, Mass. SLIGHT scratches on window glass, whether common or plate glass, some- times may be removed with raw cotton charged with jeweler’s rouge. “Sa etn AFTER her house had been painted recently, a neigh. bor of mine spent her spare time for a week scraping paint from the margins of the window-panes, Such work is unnecessary. Even an amateur painter can avoid getting paint ‘Helper’ for Painting Sash sagqueeennee on the window-glass if he uses a painter’s tin, or ‘“‘helper,” as it is sometimes called. The one illustrated is an improvement over the usual tin or cardboard helper, because it is made exactly the size to fit the smallest panes, in this case about 8 by 10 in., and has a handle. The handle is from a discarded coffee-pot. When painting around panes larger than the helper, it is necessary to shift the tin along, but the handle makes that easy to do and allows the protector to be held so firmly that there is little danger of paint getting underneath the edges and on the glass.—GEoRGE T. BROSKI, Northfork, W. Va. Relini A CRACKED chim- e sung a ney is dangerous Chimney and a serious fire hazard. In some cases a repair can be made cheap- er and without any skill in masonry work by the method illustrated. Put some old rags or paper in the bottom of the chimney, where the stove-pipe enters, and then connect some old_ stove- pipes and lower them inside the chimney. Fill in all around with concrete, using a mixture rich in cement. The con- crete should pour readily and flow around the pipe without leaving any voids.—OSCAR M. ANDERSON. [HA (A pedtrtmesy//A | 1CRETE allt Y emit a 5 Ly Urn | BASE OF CHIMNEY PLUGGED TEMPORARILY. August \ t t V t ]

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USt, 1995 Ayes . 1inter’s called, yement helper, 2 to fit ut 8 by ndle is larger 0 shift es that ctor to ; little th the GE T, chim- gerous us fire some cheap- asonry Put om of 2nters, CON? ( ARILY. August, 1925 POPULAR SCIENCE MONTHLY The Home Workshop Large Kite-Flying Reel Built from Old Bicycle Parts By Hugo Ljungquist UT of some material from a discarded bicycle, I assembled the kite-flying and game-fishing reel illustrated. The coaster brake was used for the drum on which the line rolls up. The sprocket wheel and chain also were used. The handle is from an old meat grinder. The ball bearings are of an inexpensive grade. The base, which is collapsible, is 18 by 18 in. and is made of six pieces of ¥4-PIVOT BOLT fa Construction of the reel, which is mounted upon a base as shown in the photograph above 1 by 1 by % in. angle iron loosely joined with 5/16-in. rivets. Using this reel, I have flown kites 114 miles high with perfect control and ease; and when the lure of the sea called, I have gone down to the fishing place and with the same reel landed quite a few big drumfish and other game fish. Salvaging a Wire Rake AWN rakes with wire teeth are some- times of such weak construc- tion that the bar holding the teeth breaks from the handle portion. The accompany- ing illustration shows a novel and simple way of prolonging the usefulness of such cripples by wiring the bar to a heavy gar- den rake, thereby making a very satis- factory combined lawn and garden rake. —E. W. CorRNELL, Adrian, Mich. SHAVING CREAM We tried 130 times Before we perfected this unique Shaving Cream Now let us send you a 10-day tube to try GENTLEMEN: It is only after great effort that great things are done. We worked for 18 months perfecting Palmolive Shaving Cream. The 130th formula tested was the first to please us. We knew we had a tough job before us winning men. Most of you were wedded to a favorite preparation. Outstanding superiority was our only chance. We asked 1000 men their supreme desires in a shaving cream. Then set out to meet them. We’ve Won We met those desires—and more. Millions have flocked to Palmolive Shaving Cream. Today it’s the leader in its field. 80 per cent of the men who use it were won from other makes. You know and we know that such results do not come by chance. 60 years of soap study stand behind this unique creation. It is different—radically, and immeasurably different—from any shaving cream you have ever tried. 5 New Delights These you'll find—these new shaving joys, these comforts unknown 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 The palm and olive oil content leaves the face in fine condition. 10 Shaves Free Now in justice to yourself, and in courtesy to us, please accept a 10-day tube free. Give us a chance to prove our claims. Find out for yourself whether your present method is not failing in some important ways. * % + To add the final touch to shaving luxury, we have created Palmolive After Shaving Talc— especially for men. Doesn’t show. Leaves the skin smooth and fresh, and gives that well- groomed look. Try the sample we are sending free with tube of Shaving Cream. THE PALMOLIVE COMPANY (Del. Corp.), Chicago, Ill. PALMOLIVE os 10 SHAVES FREE *\to"Shaving Tale Simply insert your name and address and mail to Dept. B-1041, The Palmolive Company (Del. Corp.), 3702 Iron Street, Chicago, Ill. Residents of Wisconsin should address The Palmolive Company (Wis. Corp.), Milwaukee, Wis. 6 6: 06 0: 650.6 0 © 016 © 6 0.0 0.6 Oe OO 6:6 6.0.8 6:6 6 66 6:10:06 OO © 6S S:O)O 0.0. @ 6 O10: E.6 O08 0 6.4:0:6 6.6 OCC SCECREOSCE CE CERE © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17.

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Saws for the big woods from “The Saw Makers” Wherever men depend on cutting tools most —and the timber faller or log bucker cer- tainly depends on them—they get best re- sults, easiest and quickest cutting with Simonds Crescent-Ground Cross-Cut Saws. It’s the Simonds exclusive method of grind- ing cross-cut saws, coupled with the heat treatment of perfectly tempered Simonds Steel, that produces these easy-cutting, edge- | holding, economical saws. Sold by hard- ware and supply dealers wherever timber is cut. SIMONDS SAW AND STEEL CO, Fitchburg, Mass. “The Saw Makers” Established 1832 Branch Stores and Service Shops in Principal Cities SIMONDS SAWS FILES KNIVES STEEL POPULAR SCIENCE MONTHLY August, 1925 Are You Making Use of Our Home Workshop Blueprint Service? Thousands of readers save or earn money by constructing furniture and radio sets home workshop and combine the fun you get from working with tools with the production of really valuable, useful, and satisfactory furniture, radio sets and equipment for your house and garden, you should take advantage of POPULAR SCIENCE MONTHLY’S series of blueprints. These are what patterns are to the woman who makes her own clothes. They provide at a nominal price the design, style, and methods of construction. They are an insurance against the blunders in & YOU wish to make the most of your | design and workmanship that so often detract from the value and usefulness of | an amateur mechanic’s handiwork. Many readers of POPULAR SCIENCE MONTHLY now never undertake an elaborate project without a blueprint to guide them. Letters of appreciation come to the Editor from all parts of the world. Here is one from Mr. C. Stenti- | ford of Dunedin, New Zealand: Once again I have the pleasure of addressing myself to you. I should esteem it a favor if you would forward to me the blueprints I have marked on the inclosed coupon, Nos. 17, 24, 26, and 39, I have had no difficulty in following the methods and details in the blueprints that were sent to me and I think heartiest con- gratulations are due to you, as well as sincere thanks from all home workers who use the opportunities that you offer them by featur- ing for their benefit the Home Workshop and Blueprint Departments. The Editor asks why we read POPULAR ScreNcE MontHiy. Well, he edits the mag- azine and should know the class of material he puts into it. It is full of all sorts of kinks, helpful methods of working, interesting articles on all manner of subjects, and any man who cannot find something to interest him in P. S. M. ought to be with his ancestors, In the February issue, the latest to hand here, you have-the details of a Salem chest (Continued on page 87) Complete List of Blueprints AY one of the blueprints listed POPULAR SCIENCE MONTHLY for 25 cents. answer any specific questions rela- tive to tools, material, or equipment. Blueprint Service Dept. GENTLEMEN: prints, I have waenee below, for which I inclose. . Seer cents: No. Title Published Price 1. Sewing Table Feb., ’22 25c 2. Smoking Cabinet Mar., ’22 25c 3. End Table Apr., 722 = 5c 5. Kitchen Cabinet May, ’22 25c 8. Shaving Cabinet June, ’22 25c 9. Arbor, Gate and Seats July, ’22 25c 10. Porch Swing * Aug., ’22 25c 11. Bench and Tilt Table Sept., ’22 25c 12. Electric Washer Mct., 722 25c 13. Tea Wagon Nov., ’22 25c 14. Christmas Toys wec., "22 26c 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 Apr., ’23 25c 20. Flat-Top Desk Arr., ’23 25c 21. Colonial Desk Apr., 723 25c 22. Cabinet and Desk Apr., ’23 25c 23. Pergola Garage May, ’23 25c 24. Gateleg Table June, ’23 25c 25. Canoe Sailing Outfit July, ’23 25¢ 26. Baby’s Crib and Pen Sept.,’23 25¢ 27. Kitchen-Cabinet Table 28. Pullman Play Table 29. Toy Tea Cart, etc. Dec., ’23 25¢ 30. Tool Cabinet, etc. Jan., ’24 25¢ 31. Sewing Cabinets Feb., °24 25c¢ 32. Chinese Game Table Mar., 24 25¢ 33. Dining Alcove Apr., ’24 25c¢ 34. Garden Trellises May, ’24 25¢ 35. Simple Radio Cabinet Oct., °24 25¢ 36. Rush-Bottom Chair Nov., ’24 25c 37. Simplified Bookcase Dec., ’24 25¢ 38. Sheraton Table Jan., °25 25¢ 39. Salem Chest Feb., ’25 25¢ 40. Desk in Sheraton Style Mar.,’25 25¢ 41. One-Tube Radio Set May, ’25 25c 42. Three-Stage Amplifier June, ’25 25¢ 43. Four-Tube Receiver July, "25 250 RIENE re Po riea ese Aen Ei a Salen, eaiee (Please print) 2) HOO OOF ACO ree City and State........ : below can be obtained from The Editor will be glad to Popular Science Monthly 250 Fourth Avenue, New York Send me the blueprint, or blue- Smoking Cabinet and Workbench A smoking cabinet (Blueprint No. 2) anda home workshop bench (Blueprint No. 15) are illustrated at the left. Hinged ashtrays are concealed in each end of the smoking cabinet. Four attractive meth- ods of ornamenting and finishing are possible— varnished, painted with a floral design, carved, and inlaid. Both the smoking-stand and the bench are detailed fully in the blueprints © This seal on a radio or tool advertisement sigrifies the approval of the INSTITUTE OF STANDARDS. See page 17. of « con: and hav hol exp! occt ture the sing 1 zine Be proje see j has recor print had ° toa! but 1 the | is ar prob diffe: sugg is n equa com} sive coni: deta aw ceabi ance seat pens how the 1 veni dra worl prot lifet man sim] brin neal ceec rece ara witl evel to b aud ably voi rece dete acc am] this For low 4 Ins pri mai De}

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st, 1925 Le ts ed om 25 la- nt. August, 1925 POPULAR SCIENCE MONTHLY The Home Workshop Are You Using Our Blueprints? (Continued from page 86) of drawers. I have studied the method of construction as portrayed by the drawings and think that that is the simplest way that I have seen in anything of that line. A House- hold furniture, even the plain models, is pretty expensive in this part of the world, and it occurred to me, could other articles of furni- ture of the box or cabinet style, be built on the Salem plan—a wardrobe, for instance, with single door. | : In conclusion, permit me to extend to you my best wishes for the success of your maga- zine. It is a classic. Before you start another elaborate project in your home workshop, why not see just what the Blueprint Department has to offer you? Especially to be recommended are the following blue- prints: ' No. 2—Smoking Cabinet. So popular had this been that the tracing was worn to arag and the blueprint was withdrawn, put the orders continued to come in and the blueprint had to be re-issued. This is an extraordinarily good woodworking problem for the beginner, because several different ways of making the cabinet are suggested and, while the workmanship is not difficult, the finished piece is equal to some of the most expensive commercial cabinets featured by exclu- sive Fifth Avenue, New York, tobac- conists. No. 5—Kitchen Cabinet. Contains the details and complete bill of materials for a white enameled or varnished kitchen cabinet of especially attractive appear- ance. The design includes a self-contained seat, which is rarely found on even ex- pensive commercial cabinets. No. 15—Home Workshop Bench. Shows how to construct a cabinet type bench of the most substantial kind, with every con- venience in the way of cabinets and drawers—a bench that it is a delight to work at, one that any mechanic would be proud to own, and one that will last a lifetime. No. 41—One-Tube Radio Set. Every- man’s radio set. It is exceptionally simple in construction, easy to tune, brings in distant stations with clarity and near-by stations with volume not ex- ceeded by any other type of regenerative receiver. For the man who does not own a radio set, this is an excellent one to start with; for those who already have sets, even multi-tube receivers, this is very apt to be a revelation in efficiency. No. 42—Three-Stage Amplifier. An audio amplifier designed to give remark- ably perfect reproduction of music and voices. It can be added to the one-tube receiver (No. 41) or to any other good detector circuit. Radio fans who are accustomed to the average two-stage amplifier will be amazed at the quality of this resistance-coupled amplifier. No. 43—Four-Tube Radio Receiver. For its superfine quality, it is one of the lowest priced sets a radio fan can build. It has been tested and approved by the Institute of Standards. If you wish one or more of these blue- prints, fill out the coupon on page 86 and mail it at once to the Blueprint Service Department. From all over the world | they come to BRown & SHARPE for Tools — In every nation men who work with metal look to Brown & Sharpe when they need tools for ex- acting work. They know the reliable accuracy and convenience of design of Brown & Sharpe Tools— accuracy and convenience proved on the job every day. And so, from all over the world, they come to Brown & Sharpe for tools. He cae = - : ih t E Z 0; a4 ‘Ay 4 pe eas y 1 Bw A Ye Wy Y, j Whether he is a garage man in London, a machinist in Turin, a Russian mechanic or a French mechanician, he reads a Brown & Sharpe micrometer and knows he is right. In every language, “Brown & Sharpe” means “tool superiority”. Send for our Small Tool Catalog No. 29. Then specify Brown & Sharpe when you buy tools. Brown & Sharpe Mfg. Co. Providence, R. I., U. S. A. BROWN & SHARPE TOOLS ‘“‘Standard of the Mechanical World’”’ © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17.

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Turn cap, at bottom of “Yankee” Push Drill, to get exact tension forevery job. Seven Tensions at the turn of the cap Want to bore a 1/16 hole in brittle wood? Turn cap on handle to left and get an easy, light tension. Next you may need to drive a 5/32 drill into rough timber. That needs a powerful tension. You can get it by turning cap to the right. “YANKEE” Automatic Push Drill No. 44 The only push drill that can be regulated to suit each job. Saves time, effort and drills. Eight drill points, 1/16 in. to 11/64 in. held in maga- zine in handle. ‘ Yankee” tension, for those who do not need this feature. Some other “ YANKEE” Tools Ratchet Bit Brace Spiral Screw-drivers Ratchet Hand Drills Ratchet Breast Drills Dealers everywhere sell “Yankee” Tools ““Yankee,’’ on the tool you buy means the utmostinqual- ity, efficiency and durability. FREE to those who love good tools (| The “Yankee” Tool Book de- lightseverytool lover. Write for a copy of this FreeTool Book NortuBros. Mre. Co., Philadelphia, U.S.A. "YANKEE" TOOLS Make Bet Mechanica POPULAR SCIENCE MONTHLY August, 1925 NE of the professional stunts ex- O hibited by theamateur or profession- al magician is that of causing an unprepared playing-card to rise from one Adjustable No. 41, without adjustable | ‘Ten-Cent Measuring Tape Used iz Making a Magic Card “Pull” By Kenneth B. Murray Purchase a small spring measuring-tape for 10 cents and after unwinding it, cut off all but an inch or two. Tie a fine black silk thread to the stub of the tape WS hand to another 12 in. or more above, The trick can be duplicated readily by making what magicians call a “pull,” as shown below. When as much thread as possible is wound up, cut it off near the case and tie a small button firmly on the end The button must be treated so thet it will stick to a playing-card. This is accomplished by smearing one side with common beeswax exerted on ‘In presenting the effect, hold the prepared button between the first and second fingers and take care to stand against a black background. Ail- low the cards to be ex- amined if you wish. The button then is pressed against the top card of the pack, which is held in the left hand. When the card is released, it floats gracefully to the right hand because of the pull the black thread by the spring in the tape-measure case A strip of surgical adhesive tape is used to fasten the measuring-tape box on the back of the wrist. Care must be taken to place it suffi- ciently far back so that the coat- sleeve will conceal it completely CHEDULED for early publication are the following articles: How to Fit Up an Attic Room, Repairing an Elec- tric Iron, Simple Pocket-Knife Carving, A Unique Doll Boxing Game, How to Apply Polychrome Finishes, A Spiral- Leg Davenport End Table, Relining Automobile Clutches, How to Make an End Lap Joint, A Workshop Nail Cabinet, Homemade Jigsaw, Construct- ing and Finishing a Two-Tone Radio Cabinet, Novel Mats and Baskets Made from Corn Husks, A Ball-Bearing Drill, and a Photograph-Print Washer. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17. oe zh th oot

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gust, 1925 —__

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ke an Nail ruct- tadio Made Drill,

August, 1925

— The Home Workshop Toy Model of Racing Airplane Whittled from Soft Wood W HETHER or not you have whittled the toy airplanes described in the June and July issues of POPULAR SCIENCE MONTHLY, you will find the racer model illustrated below easy to make and at the same time a realistic and fascinating toy. This model, when neatly painted, amuses the children better than the flimsy tin airplane toys that are now so common, and is far more durable. The body is whittled from a piece of soft pine or other wood % by 1\% by 7 in. The wings, which are 3/16 by 8 in., are fastened to the body with brads and glue. The landing gear consists of two wooden

=

Whew LZ LANDING GEAR > @ EXHAUST z PIPE 34) ‘ mL nae ' Whatever dimensions are not given in these drawings can be estimated closely enough by eye <2%4

wheels 3/16 in. thick and 1 in. in diameter, mounted on a wire axle, as illustrated. The tail members are cut from thin sheet metal and inserted in slots in the body. Brads are used to make the fastenings secure. The propeller also is thin metal mounted on a brad or escutch- eon pin driven into the nose of the body. A glass bead serves as a spacer between the wood and the propeller. The exhaust pipes are cut from a 3/16-in.wooden dowel. The body should be painted dark blue and the wings gray. The cockpit may be merely a circle painted black or a shallow hole bored into the top of the body, just behind the trailing edge of the upper wing. The fourth toy in this series will be an express cruiser.—D. W. C.

Sliding Clothespin Bag ANGING out the family wash on a clothes- line of the yard type —one that has no pulleys — is made easier by the use of a sliding clothespin bag like that illus- trated. The bag is fastened to a wire frame.—I. E. Hou.

POPULAR SCIENCE MONTHLY Saws are blind as bats! OCCASIONALLY they will strike a snag that even you cannot see, working havoc with their finely tem- pered teeth. But a good saw has amazing recu- perative powers--especially when “treated” promptly with the right NICHOLSON File. Most carpenters use NICHOLSON Files--eas do woodsmen, mechanics and skilled artisans to whom accurate filing, with economy of time and ef- fort, is a major consideration, © NICHOLSON FILE COMPANY Providence, R, !., U.S.A, grors, NICHOLSON “&” “FILES —a File for Every Purpose

89

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17.

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Buyers of good tools, the kind of tools that give husky, long-lived service, will want V&B Vanadium . Hammers and V & B Unbreak- | able Planes for | their kits.

» They ‘re two thor- ' oughbreds that | will give you years of service.

VAUGHAN & BUSHNELL MANUFACTURING COMPANY (Hakers of Fine Toots 2114 Carroll Ave v

POPULAR SCIENCE MONTHLY August, 1925

~ Chicago, lil. U.S.A.

How to Build a Ventilator Louver Type of Opening Simple to Install in a Frame House or Garage By Edwin M. Love OOF ventilators, R either through damage or desire for a change of design, occasionally need replacement. For the frame house there is probably no better type than the louver vent, which consists of a number of horizontal vanes inclined so as to shed rain and snow, and cased up in the manner of a window- frame. Such vents are adaptable to almost any size or shape of opening, and if carefully made are not only well suited to their purpose, but are artistic. Whetherthe house is sided-over sheathing, or the weatherboarding is nailed direct to the studding, matters little in the building of the ventilator. The outside width of the frame should be at least 1 in. narrower than the

1G}. longer than the inside width of the vent, and nail in place with the lower edge 8 ip. above the lower edge of the top vane. Square the assembly, and cut in the side casings. An easy way to get the length of a side casing is to cut the bevel on the lower end, lay the vent on its back, and lay the casing upside down in place with the point against the sill and blocked up from the jamb 34 in., and mark the upper end by the head casing, Cut a trifle long so that the joints will be forced tightly together when the casing is nailed on, Put the inside edge flush with the face of the jamb. Cover the back with screen wire to keep out birds and flies. Cut off the sill horns so that they

distance between the side trimmers of the opening, to allow for wedging and plumbing, while the height must be such that it easily will clear the trimming headers. Use 1 by 5 in. stock for the jambs. Joint and surface the two at one time, as a pair, and lay out both for dados to receive the ends of the vanes as follows: At the bottom, a groove 1% in. wide, and at 3-in. intervals, measuring top to top, grooves 34 in. wide, all inclined at an angle of 60 deg. with the edges. Gage these for a depth of 34 in., saw the sides by cutting in the waste wood, and re- move the chips with a chisel. Some workmen merely butt the ends of the vanes to the jambs, but the vent is much more difficult to assemble and the construction is decidedly poor. Cut all the vanes of 1 by 6 in. pine 34 in. longer than the inside width of the ventilator. The 2 by 8 in. sill is beveled on the edges to correspond with the slope and is notched from the back at both ends to the width of the jambs as measured along the dado. The main length of the sill therefore is equal to that of the vanes. Leave the projections r “horns” 5 in. long. Assemble all the vanes and one end of the sill with one jamb and then nail on the other jamb. If the parts are oiled or primed before assembly, the job will be so much the better. Plane the projecting edges of the vanes to aline with the jamb edges. Use 1 by 4 in. clear stock for the casings. Cut the head casing 10 in.

project beyond the edge of each casing, a distance equal to the

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4 / ZAF DETAIL O = <u END Front view and end section of a rectangular louver vent, and details showing end of sill projection in front, or about lin. Give the same amount of projection on the head casing as is shown on the head casings of the house windows. In setting, slip the ventilator into

(Continued on page 91)

© This seal on a radio or tool adrxrtisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17.

| Jover | sun-¢ | earn feath Th lustr: jn.) ¢ roug! roun by 1 4 ft gro basit the | | from | piec | in d 11 it | glue | the : | top |] | dou | the | rem | only | or e the the: or € T of a rim. may shel

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Page 79

Or all inside it, and 2 3 in, » Vane, in the h of a mn the back, 1 place Olnt ill and ym the » and er end casing, Ong so ts will tightly n the ed on. e edge 2 face Cover screen Pp out 2 sill ; they d the sing, a to the AIL O Gh ular sill re the head sings into Birds’ Bath and Sun-Dial Made Entirely of Wood 0 GARDEN is complete without some provision for the birds. Bird ‘Jovers may combine a birds’ bath and a | gun-dial with pleasing effect, and thus earn the lasting gratitude of their little feathered friends. ; The center column of the stand il- lustrated (2 by 3 aaa : jn.) and the four |i. : rough slats sur- rounding it (14 by 1 in.) extend 4ft. above ground. The pasin nailed at the top is made from two circular pieces, each 2 ft. in diameter and 1 it. thick, one glued on top of the other. The top piece is like a doughnut with the large center removed, leaving only a 3-in. rim or edge on which the figures for the sun-dial of the twelve hours are carved or even painted, as your taste dictates. The shadow is cast by the extended bill of a carved wooden bird perched on the rim. The under side of the plate or bowl may be carved to represent a large sea- shell—A. MAY HOLADAY. Both bird and bath are carved Tin Strip Safeguards Contents of Tightly Packed Drawer O PREVENT SHALLOW objects in a drawer from catch- ing when the drawer is pulled out, I fasten a piece of tin to the upper drawer rail as shown. The tin is about 5 in. wide S8ENT-UP TIN and. not quite as NEARY AS LONG long as the drawer. The inside edge of the drawer is planed down so it will not rub against the tin, which is invisible when the drawer is shut. —ARTHUR FLINNER, Wichita, Kans. V7} 9, y Yy SS i iG % 4 3 WSs " NN Ss Building a Ventilator (Continued from page 90) place from the outside, plumb the jambs, and nail through the casings and head into the side trimmers, afterward wedging the sides and sill tightly. Lastly, put underneath the sill an apron made of 3-in. bed molding with a return mitered on each end. If it is desired to have the siding boards butt against the casings, set the vent without casing and fit the casings one by one to the ends of the boards. Or, if it is new work and the siding is not yet on, first build the ventilator com- plete and fit the boards to the casings after it is finished. POPULAR SCIENCE MONTHLY Lightest— Most Compact— Most Complete Portable With 4-row Standard Keyboard OUR years ago Remington announced the portable typewriter with a 4-row standard keyboard—the keyboard universally adopted by business as the best. In this comparatively short time the Remington Portable has become the leading personal writing machine throughout the civilized world. The New Remington Portable is fundamentally the same tried and true typewriter, with several improvements that make it un- equaled in general efficiency. 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 accommodates full width paper and long envelopes; it has the finest touch and action; it does beautiful work; its durability has been proved; and al/ the writing is always visible. The New Remington Portable is sold by Remington offices and dealers everywhere. It is backed by a service that is universal. Be sure to examine the New Remington Portable, or write for our booklet “For You—For Everybody.” Address Department 67. REMINGTON TYPEWRITER COMPANY 374 Broadway, New York — Branches Everywhere Remington Typewriter Co. of Canada, Limited, 68 King Street West, Toronto We believe we make the best typewriter ribbon in the world—and its name is PARAGON Remington Portable THE RECOGNIZED LEADER—IN SALES AND POPULARITY © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17. Ns

Page 80

fee ae ae Mele N ER: SOY Majestic Roll , of the ) Mighty Organ 0 ( e SOOYN “. Reneait ans, al Ly KN OON ND Mighty tones from the depths of the noblest of musical in- struments do not tax the resources of Rauland-Lyric. Ac- curately designed for faultless amplifica- tion, this instrument faithfully transmitsall organ tones —those of the piccolo stop as well as those of the open diapason. enews SOOY x SZ SOON OSyYy pm SWOSY. SOO ae KOSS x o SOO x KS IOOYNSNN Rete ened x OOS NOON Ww XM SOO Pane encodes SSeS, NOVO “ OSY x Aton eons CoG yA ye ~~ M, oe AK . YOoy, =, cx a a Katey LON %S ys. % SOON) A.— =X MOSS Kes ~ KY es =. WN So" ow i Kom NWNOCY ee 4 =X MOSS Rauland-Lyric is a laboratory- grade audio transformer de- signed especially for music lovers. The priceis nine dollars. Descriptive circular with am- plification curve will be mailed on request. All-American Radio Corporation, 4201 Bel- mont Ave., Chicago. N OO se LOOX ‘sZame""aTae” re ope, cx oO NO Aoneteent 4 SOSs tentaet DOK TRANSFORMER The Choice of Noted Music Critics POPULAR SCIENCE MONTHLY August, 1935 \ N JHENEVER long boards or tim- bers have to be cut to length in any quantity, a swing-saw is al- most indispensable. The owner of asmall wood-working shop, the farmer who does much construction work, the small build- ing contractor, and the pattern-maker can build the frame for such a saw at rela- tively small cost for material by following the design illustrated. This is not only a cheap saw to make, but is also a sturdy machine and one that with proper handling should last for years. The material from which it is constructed is standard and there 4 — ZO) ZA =~ sf ( 7] Sy) Rav = Hh The Home Workshop| Sturdy Swinging Cut-Off Saw Frame Made of Pipe and Fittings By Frank N. Coakley bearings. This is especially necessary for the saw mandrel. For the saw mandrel another piece of 134-in. cold-rolled steel is used. The saw end is turned down to 1 ip, diameter and a left-hand thread cut for a1¥-in. nut. This shoulder acts to back up the saw washers, which should be about 7 in. in diameter, 5% or 34 in. thick, beveled as shown. The pulley on the mandrel is 5 in. in diameter with a 5-in. face, securely keyed to shaft, which runs about 2000 r.p.m. The frame itself is made of lengths of pipe. While 6 ft. 6 in. is called for, 6 ft, would work out satisfactorily, but any- thing shorter would give too short a belt for driving at the speed mentioned. A cross brace is provided to prevent any weaving action in the frame. All the AUAVULT AAU | should be no trouble in pur- chasing it, even in small towns. While no sizes are given for the various fittings, I do not advise the use of anything smaller than 2\%-in. pipe for this size ‘saw. However, if one were to build a frame for a 12-in. saw, 2-in. pipe would be heavy enough. The frame is hung from two brackets of pipe that are fastened to the side wall with two standard flanges. The tees on the brackets are machined to allow the end pieces of the swinging frame to pass through. The top and bottom tees of the frame are babbitted to form the bearings for the countershaft and the saw mandrel. The countershaft is a piece of 134-in. cold-rolled steel, having a keyway for a 3%-in. square key. The small or driven pulley is 10 in. in diameter with a 5-in. face; the driving pulley is 18 in. in diame- ter and 5-in. face. The countershaft is to be run at 550 r.p.m. At this juncture, care must be taken to provide oil or grease cups and to be sure that the lubricant gets into the _ This swing saw, which is designed for the small shop, can be built without expensive machine work joints must be perfectly tight, as the ma- chine may receive more or less abuse. Two handles are fastened, one to each frame, for pulling the saw through the wood. This operation can be done just as well with a foot lever carried up in back of frame and fastened to the bottom tee with a link. To pull the saw away from the wood, a counterweight is used. While some prefer springs, the counter- weight is always dependable. The table may be made from any lumber that happens to be handy. The back board can be made a sliding affair, if desired, steel angles supporting and hold- ing it to the table. It is essential, of course, to provide some kind of a guard for the saw. 1S] This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17.

Page 81

eed nall york he ma- ise. (0 each gh the 1e just up in bottom y away s used. ounter- m any . The ffair, if d hold- provide w. Chemistry Will Save Time Fest preservative is creosote. This can be applied by boring a small slanting hole in the base of the post just above the ground and filling the cavity formed with this liquid. The hole then is stoppered with a small plug. Three or four days later more creosote is added and the hole again plugged. At the end of a week a final addition is made and the plug perma- nently fastened in place. Wood that has been darkened can be bleached, as well as naturally dark lumber such as walnut. Ordinary bleaching of lime, is mixed with water to form a thin paste. This is applied to the wood and allowed to dry. The dry paste then is moistened with diluted hydrochloric acid made by adding one part of the acid Applying a bleaching paste to dark wood Mixing dry chloride of lime with diluted hydro- chloric acid to three times the volume of water. After a few hours, clean the wood. If it is not sufficiently bleached, repeat the process. Certain precautions are necessary when two pieces of wood are to be joined by glue. Carpenter’s glue should be broken into fine pieces and soaked in cold water. Never add hot water as it will prevent the glue from swelling throughout its entire mass; just the outer layer will dis- solve. Use just sufficient cold water to cover the glue. After all particles of glue have sunk to the bottom or stuck to the side of the vessel, a little more water is added so that all the glue is sub- merged. After soaking about 10 hours, the glue is heated to just below the boiling point— so that it will melt. Never boil the glue; joints made with boiled glue never will be as strong as those joints united with glue that has been heated just enough to make the jelly fluid. Glue, when it hardens, becomes brit- tle, and since flexible glues are required for certain types of work, such as re- gluing the bindings of books, glycerine is added to the glue. The quantity of glycerine added after the glue has been melted inthe ordinary way usually is equal to the weight of the dry glue used. The glycerine is stirred in after the glue has been liquefied. powder, which also is known as chloride | Home Workshop | Simple Formulas that | and Money | OR posts placed into the ground, the | POPULAR SCIENCE MONTHLY ““Have you plenty of patches for your 5- Minute Vulcanizer?” You know what a joy killer a puncture is— especially when you’re on a country road and your spare has been used. Ford or Packard— it happens to any car. Nor is it less likely with balloon tires. When it happens to you—what’ll you do? - Ruin the casing by driving it flat—or wait till help comes? You and 3,000,000 other motorists got the Shaler Vulcanizer because it is the quickest and easiest way out of such an emergency. Be sure you are not out of ammunition to use with it. Use Before Re-Tiring | Be ready to clamp on a Shaler Patch-&- Heat Unit, light the prepared solid fuel it con- tains,and give ita few minutes to cool. Anyone can do it on the road or anywhere quicker than sticking on a temporary cold patch. If You Haven’t a Shaler Vulcanizer Get This “‘Hole Outfit” Today Only $1.50 at Auto Supply Dealers Everywhere Slightly Higher in Canada and Far West Includes 12 Shaler Patch-&-Heat Units—6 round, 6 oblong C. A. SHALER CO, 2104 Fourth St., Waupun, Wis. Vel ER SS r M 5 Minute Smack N VULCANIZER ‘ @ This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17.

Page 82

POPULAR SCIENCE MONTHLY August, 1925

ee: PERV TTT VEC TE $85 vrvveyveret s¥e = 5 Ae,

Why YOU Want ATKINS “400” For those who want the best of tools for the best work— ERE is a hand saw made of the finest steel the great Atkins laboratories can prescribe— genuine “Silver Steel”—ready to outwear and stay sharp longer than any ordinary” saw. It is two-way taper-ground by Atkins patented process to makeitcuteasier and quicker. Solid Rosewood handle, piano finish; Improved Perfec- tion pattern—prevents wrist strain. Nickeled screws. Atkins “400” is made es- pecially for every mechanic who takes pride in owning the very finest hand saw that money and skill can produce. Good hardware merchants all over the world show and guarantee you the famous Atkins “400” and other Atkins Saws for every use in cutting wood, stone and metal. It will pay you to buy a saw with the Atkins name etched on the blade Ask for our booklet “Saw Sense” E. C. ATKINS & CO} EST. 1857. INDIANAPOLIS, U. S. A. ° Leadin; manufacturers _of Saws, Saw Tools, Saw 5 palace ties and Machine nives. i aimed peor Be eek er hax \ Pree VERT VYVPTVYNT? v¥

© ATKINS sTEELOAWS

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17.

Hooded Cab for Model Locomotive Sixth Article on Building a Miniature Railway ROADLY B speaking there are two types of cab for an electric locomotive—the car body type and the central type with hooded ends. The for- mer was illustrated so fully in the fourth article of this series (June issue, page 96) that nothing further need be said about it. The hooded-end locomotive illustrated is not, strictly speaking, a model, for a true model must reproduce not only al! essential details, but must be made accurately to scale. This does neither, but its defects are such that only a per- son familiar with its New York Central proto- type would be likely to detect them. You may start with a built-up under body sim- ilar to that in the fourth article. In this case, however, you must omit the heavy bumper beams needed for the car-type of body. Substitute light end pieces as illustrated below. Do not for- get the little slots near the left-hand side of each end. These are for the uncoup- ling levers to be described later. Another variation from the basic con- struction previously described is in the location of the reversing and control switches, as the cab is smaller and has windows in different positions. The central cab is 8 in. long, 5\% in. wide, and4in. high. The outside surface of its sides should come precisely flush with the outside of the under-body sills. The % by % in. molding strip over the sills should be omitted in this locomotive.

By Edward E. de Lancey

The best material for the cab and hoods is light cigar-box stock, approximately \& in. thick. It must be straight grained dry and free from warp. For the sides of the cab, select two such pieces, 8 in. lon by 334 in. wide. Fasten these together temporarily with light brads or pins, and see that all edges are square and match exactly. The two out- side surfaces of these pieces will be those of the finished cab, there. fore, in anticipation of future painting, give =e them a smooth, dry Wie finish with sandpaper, Mark out the windows and doors as shown and cut them with a fret- or coping-saw, after drilling a small hole at diagonally op- posite corners of each space for an opening to allow the insertion of the saw blade. As the superstructure is to be a single continuous structure from end to end, both sides of each hood are continuous from A to B. These, when finished, will pass inside of the cab walls, as shown by the dotted line C-D-E-F. Beyond the main cab ends, the hood walls will leavea narrow strip exposed to represent the wider deck of a real locomotive, as marked on the partial plan view. These two pieces will range from 2 to 2% in. high and will be 173 in. long. Fasten them together and saw as in the case of the two sides of the cab. Fasten the hood sides firmly with small, sharp head- (Continued on page 95) (nee

ROUNDED WOODEND __,& 3, CROSS BRACES 2x2

‘ ZINC Exes ; Gh ----~ Te] BRASS RAIL } ae ‘s 0 ee 1 , A P 7”AB a ea On Pe eat 2 ' wer StH SILL L-.! K DOOR Y | ats. Anandroneshedeolinioccsodnalonteembanledbiedaale E SSCL eno tities PIECES VENTILATOR) DECK ZINC TOP Z SLOT. ‘4 DY! NDOW>)) | ; ZINC SLOPE ==] NV EnD/ Ii = =" BRACES ROUNDED END = = VERTICAL ZINC= fi SILLS SIDES OF HOOD DECK Side elevation and sketch (accessories omitted) of a model locomotive with hooded ends; cross section through the cab looking toward inside of hood, and plan view of one end of hood

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less pi Be | are ex’ recisé ie at t the wl this I gurfac with Now ¢ such betwe of sid The proba troller placec The good adjac fine r H be is pli sheet distal hoods reach C, an trifle matt file < place will | trim unne M: corne close EB: abou is le This wind two | the place W brou line exac of t] serie large heac not | liabl 7: com: and inst: C! rugs hes may sho the ove! the arol

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ust, 1925 —$$__

‘Ive Ly naterial d hoods ately rained, sides of in. long ogether ns, and . Match WO out- f these hose of ), there. ation of g, give th, dry dpaper, yindows shown with a ng-saw, 2 small ally op- of each opening ’ blade, a single to end, tinuous ed, will } own by md the leave a nt the ive, as These 23% in. Fasten case of ten the p head- xe i /

Lfuchteal i Ab | fi

i - The Home Workshop the spacers placed 1 in. each side of the center line. complete. and ventilators will be left until the next installment. Tugs, heavy fabrics, may be made as shown. First place the narrower slot over the material; then pull the pin around and fas- ten it. ———

august, 1925

Cab for Model Locomotive (Continued from page 94) less pins to the inside of the cab sides. Be certain that the two pairs of sides are exactly equal in length, that the cab is precisely in the middle, and that each pair is at the proper distance from the ends of the under body. Block them firmly in this position, and see that the outer surfaces of the cab sides are truly flush with the outer edge of each body sill. Now cut three 14 by 14 in. cross braces of such length that each will fit exactly petween the inside edges of the two pairs of sides. The positions of these cross braces will probably interfere least with the con- troller and reverse switches if they are placed near each end and near the middle. The dotted squares G, H, and J show good locations. Fasten them to their adjacent cab, or hood, sides by means of fine round-headed brass brads. HE covers over the hooded ends may be made of sheet zine, as that metal is pliable and easily handled. Cut two sheets of such width as just to cover the distance between the outer edges of the hoods, and make them long enough to reach, with all bends included, from K to C,andfrom Lto E. If they should be a trifle too wide, in spots, it is an easy matter to true them up with a fine flat fie after they have been fastened in place. In the matter of length, 714 in. will be correct enough to enable you to trim off any excess that may prove to be unnecessary. Make them accurately square at all corners, and see that the top ends fit closely between the cab corners at C and E. Remember that the zine extends about 14 in. into the cab at this point and is level under the three end windows. This level stretch is to support the window spacers. Do not overlook the two extremely fine wood screws by which are secured. They are When both zine covers have been brought to a good fit, scratch a straight line along each side, so that it comes exactly over the middle of the thickness of the sides of the hoods. series of small holes along this line, just large enough to admit very fine round- headed brass brads. not less than 14 in. apart, else you will be liable to split the wood. Now drill a Space these holes Your superstructure now virtually is Couplings, steps, hand rails,

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POPULAR SCIENCE MONTHLY 95

Amazing new receiver NOW anyone can build it in an amazingly short time this new easy way. Experts assemble it at factory. You sim- ply wire. N° excuse now for not having a fine radio. At a surprisingly low cost too. For a ramarkable plan is showing thousands a new way to build their own. It is so easy that anyone can do it in a few minutes. So fasci- nating that many continue to build them for others. No wire bending or soldering. Merely attach a few ready- cut, flexible eyeletted leads, and the job is done. And in addition to the fun and pride of building your own, the finished re- ceiver actually contains a phenomenal feature rarely found in even the most expensive sets. This marvelous feature brings results otherwise impossible. This feature follows the discovery of a new inductance principle that overcomes many vital weaknesses of present day sets. It consists of an entirely new type coil called’ the Erla *Ballon *Circloid. Circloids are integral parts of the Erla kit and are largely responsible for the striking improvements this kit alone offers. Note these four advan- tages in particular: 1. Greater distance. Circloids have no measureable external field to affect adjactent coils or wiring circuits. This makes possible higher amplification in each stage with increased sensitivity and greater range. 2. More volume. Higher r. f. am- plification enables Circloids to_ bring in distant stations scarcely audible in

Dealers—Exclusive franchises are available to high class dealers in localities still open, Write or wire immediately. Note revolutionary new principle it contains. ordinary sets with volume enough 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 circuit are built up. 4, Finer tone quality. The self- enclosed field positively prevents stray feed-backs between coils. Hence no blurring or distortion. Tones are crystal clear. Write for free information on kit— also book See how a few minutes of fun will give you one of the very finest sets known to radio science. Examine it at any Erla dealer’s, or send the coupon for full information, illustrations and diagrams contained in the remarkable new book, “Better Radio Reception,” describing the sensational new Circloid principle. Enclose 10c for mailing and postage on book. ELECTRICAL RESEARCH LABORATORIES 2530 Cottage Grove Ave., Chicago *Trade Mark Registered. This sign identifies au- thorized Erla distribu- tors, All are equipped to give complete radio service. Electrical Research Laboratories, & 2530 Cottage Grove Ave., Chicago, U.S.A. O Send me free_informa- tion on kit. Ol Enclose 10c for postage f»r book, “Better Radio Reception.”

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© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See vage 17. boat (without tools), no work, no bother. Fast—Light—Powerful Easy to Carry

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POPULAR SCIENCE MONTHLY They'll “Speak Up” Under Pressure MACHINES?—dead metal unless you drive them. Dumb brutes until you make them report on Counters. Make them tell you what they're able to do. Make them show. results in higher records. Make them guide you to improvements ! Just as sure as ‘“‘Production Talks,” you'll make your machines Speak Up on RR COUNTERS The small RevolutionCounter be- low registers one for a revolution _ of a shaft, recording a machine operation i@ 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. holder like that illustrated. door firmly while it is being planed and mortised for the hinges. idly Made Fielder for wer Work HENEVER you have doors to hang or refit, you will find it saves time to nail together a door- It grips a A piece 1 by 4 in. by 2 ft. long, not tso stiff, is nailed at each end to “two by fours,” ends about 12 in. long are cut on the bevel and nailed from underneath to the 1 by 4in. board. A little experience will show you how much space is needed between as shown. Two pieces of joist them. I find that /4-in. clearance is all that is necessary—214 in. for doors 134 in. thick. The weight of the door et the 1 by 4 in. piece and causes the joist ends to grip the door securely. On lift- ing up the door, it is released at once. When planing a door, carpenters often cut a board between the door jambs and make a notch in it to receive the door, but that method scratches the woodwork and blocks the doorway and therefore is not as good as using a holder.—R. M. REKERT, Regina, Sask., Can. Vacuum-Cleaner Motor By ©. H. Y HOME ‘“machine-shop” was M constructed from an old vacuum cleaner, curtain rods, and oak pieces. The motor operates successfully a circular saw, a small lathe, and a carbor- undum wheel, caring for all home jobs. The motor is an- Runs Small Machines Lovejoy of the blade are the square nuts on the lower end of radiator bolts of a Ford ear. The platform of the sawis a piece of 4% in. soft pine pivoted between the prongs of the old cleaner handle. The saw was allowed to cut its own groove in its table, |. which is lowered and chored to a block with two iron strips drilled to fit and at- tached by the thumb-screws of the old dust bag. The switch in the end of the cleaner is fastened to the end of the bench to be elevated by athumb- screw of an old bolt working against a vertical piece of steel screwed to the base. The lathe, which is shown turning out a vermilion wood tray, is obtained by fastening a _ small accessible for all work. A tin-can lid, perforated and bolted tight against the stone, serves asa pulley wheel for belting the grinder to the motor. The mandrel is a piece of gld curtain rod 3 in. in diameter, set in an upright The machine as set up for sawing. saw and the leather belting were purchased The mandrel, with faceplate attached, being used for turning a tray of vermilion wood oak block, with a bushing made of a hollow curtain rod. This bushing is fitted into a hole bored through the block. The pulley on the mandrel is one of the wheels of the old cleaner with a groove sawed to take a belt of the sewing-machine variety. As the saw had too large a bore, an ordinary iron washer was fitted into the hole. The retaining plates on either side iron plate with a nut on the man- drel. Two screws pass through the plate into the back of the block to be turned. The rest for the turn- ing tool is merely a ““T’’ of two oak pieces fastening to the front of the bench by a small vise. The turning tools are small files shaped at the end. The motor block is slotted, so that the two long motor screws may be adjusted Only the to tighten the belt. The mandrel block is really two blocks interlocked at right angles and fastened to a stationary base. It is surprising what clean work the device turns out and how really powerful the little motor proves. The only money spent in setting it up was for the circular saw blade and a length of sewing- machine belting. EVERY home worker will find helpful suggestions in a series of articles, ‘‘How to Fit Up an Unfinished Attic,’’ the first of which will appear next month. The series will be a veritable text- book on house woodwork. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17.

Page 85

Gust, 1925 Zi; ae p ork and > is not -EKERT, ines on the ord car. ce of 4% prongs aw was 8 table, |. red and thumb- old bolt ainst a > of steel he base. » which ning out 1 ‘wood ined by small with a > ~man- screws k of the he turn- k pieces ch by a ‘e small shat the djusted 21 block at right ry base. ork the owerful " money circular sewing- find eries > an t of nth. fext- oom aes rere eed sesessesseed a a_— ‘August, 1925 -iThe Home Workshop “Hard Edge’’ Upholstering (Continued from page 76) stitching through not to catch any of the coils of the springs. Make two complete rows around the edge of the top surface and take a few stitches through the center. To produce the so-called “‘hard edge,” first remove the tacks holding the burlap, and carefully retack along all four rails. Keep about 1% in. from the top edge. Draw the burlap down smoothly so that the edge remains even. Work from the eenter toward the legs and at the corners remove any surplus burlap, fold the edge under, and tack close to the legs. Use a 6-in. curved needle with stitching twine and take several rows of stitches, as shown in Fig. 6. Begin at the left-hand end of one of the rolls by inserting the needle into the edge at a_ point from 1 to 1% in. above the row of tacks. Let it come out at about the same distance from the outside row of top stitching that was put in previously. In- sert the needle, again about 2 in. to the right of this and about % in. from the row of stitching and allow it to emerge about even with the top of the rail. SpeekT the needle again at a point about 2 in. from where it came out and on a line with your first stitch; then pass up at a distance that will bring it on a line with your first top surface stitch. Con- tinue in this zigzag manner until you have gone around the four sides. It might be well to try several stitches first before drawing your twine up to shape. The object of this stitching is to draw the stuffing out toward the side so as to maintain an even edge and hold it there by the stitches that pass through it. When a complete row has been made, a second and a third may be done. During the making of the rolled edge it will be necessary to “‘regulate” as you go along; by this is meant, drawing enough of the stuffing up to the sides so as to fill out any irregularities that may occur in the roll. lap at the point where you wish to fi}] out shape when the twine is drawn up. through the corners. is inserted at right angles to the edge, as this helps draw the stuffing into the roll. The center now is filled up evenly with cotton batting are placed on top of this. The whole then is covered with muslin, as in Fig. 7. The corners are folded in carefully and the edges tacked close to the rabbet in the rail. The final cover is put on as illustrated in Fig. 1. tonne, velour, or corduroy, should be used in preference to leather. tacked over the bottom along the rails. This is accomplished by means of the stuffing regulator, or your needle may be used. Force it through the bur- the edge and scrape and pull enough of the stuffing to the edge to give the desired The second and third rows of stitching are made with shorter stitches and are not in the zigzag manner, but merely pass The needle always moss, tow, curled hair, or kapok and a piece of sheet wadding or several layers of Soft material, such as cre- A piece of black cambric usually is POPULAR SCIENCE MONTHLY f 97 Within the means of all Visitors from foreign countries invariably wonder at the number of telephones in America. “Why is it,” they ask, “that nearly everybody in America has a telephone, while in Europe telephone service is found only in a limited number of offices and homes?” First of all, telephone rates in the United States are the lowest in the world for the service given. Here, since the beginning, the best service for the greatest number of people has been the ideal. By constant improvement in efficiency and economy the Bell System has brought telephone service within the means of all. From the start, its rate policy has been to ask only enough to pay fair wages and a fair return on investment. The American people are eager to adopt whatever is use- ful. They have found that Beli telephone service, compre- hensive, prompt and reliable, connecting them with the-people they wish to reach, is worth far more to them than the price charged for it. AMERICAN TELEPHONE AND TELEGRAPW COMPANY AND ASSOCIATED COMPANIES BELL SYSTEM ky wo One Policy, One System, Universal Service A Tool Chest Wily for joining that combinen: stzensts and ttmost service Under allcon: radio antenna and lead-in wires in one minute itions—that is the kind you without solder, tape or tools, t wh ° = Many other uses. A million perfect joints have already been made with these new Wire- Nuts. Listed by Underwriters’ Laboratories. Booklet free. uts. Catalog free H. GERSTNER & SONS 520 Columbia St., Dayton, 0. cLEAR #150 “$300 | {| with new One Day Battery Charg- | i _, — and — eo $35 cash brings complete me Day ith elec- Battery Charging outfit. Easy | Tests bs rpeeoaprag 9B nT nye rd- terms let your profits pay balance est and finest tools and instruments,or f ; quickly. 30 day free trialon money-! | any metal, like writing on paper. with back guarantee. Write for free bul- B oF , Dencil, | Complete Out! letin telling how to make big profits, | ing illustrated circular free. Write to- HOBART BROS. CO. Box P-8 Troy, Ohio | day. Agents Gerstner Ask your dealer for Wire-N’ W. TORK COMPANY, 8 W. 40 St., New York BURN YOUR NAME ON TOOLS 3.50 Prepaid re. Interest- 171-A East Stark St., Portland, Oregon | | © We will send 3 Wire-Nuts post paid on receipt of 25c_ i\HB ONE DAY 243% | ARKOGRAF PEN CO. _- © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17. eras Seri Betas

Page 86

Quality at Every Price Cabinet or table space many times determine the size and type of radio batteries selected by the user. Burgess manutactures a battery for every radio circuit and tube. Your choice of any one of many types in- volves no sacrifice of economy or ser. vice hours The value and quality of Burgess Radio Batteries are constant — your satisfaction assured Ask Any Radio Engineer iS} Wnite to 219 ‘Burgess Engineer- ing Building, Madison,Wisconsin tor the Burgess Radio Compass. It 1s amusng, unusual and useful. % it BURGESS)! LAE [BATTERY] BURGESS BATTERY COMPANY Engineers DRY BATTERIES Manufacturers Seeptniibes tmceten ta mee Laboratories and im tae POPULAR SCIENCE MONTHLY. August, 1925 The Home Workshop | Simple Method of Making Inlays for Your Homemade Furniture By William Rodgers HEN you have a radio cabinet, smoking-stand, small table, or any other simple piece of furniture to build, why not try your hand at orna- menting it with inlays? Contrary to the belief of most amateur woodworkers, inlays can be purchased quite cheaply and applied easily. If you do not know where to purchase inlays, send a stamped, self-addressed envelope to the Information Department of POPULAR SCIENCE MONTHLY, which will furnish you with a list of dealers, or, better still, be- cause more interesting, make your own in- lays. You will find you can do it with a de- gree of success that will be quite surprising. You will need first two 2 by 4 in. by 3 ft. blocks of wood, one side of each being _--*=.. WOODEN CLAMPS 2"X 4"X 3'-0" ‘*€ ~-s__SMOOTH ON ONE SIDE = WHITE HOLLY Ye'x 4"x3-0" RED WOOD GLUED-UP PARTS AFTER FIRST OPERATION SAWED STRIPS ALTERNATED WHITE HOLLY Mex 4"X3+0" VENEER DYED BLUE Yao'x 4"x 3-0" COMPLETED sTtRIP K2" THICK ALL READY FOR INLAYING ® The four steps in making this simple border are typical of all geometric inlaid work smooth. These are for gluing blocks. They should be provided with two U- shaped iron clamps threaded to take nuts as shown and two pieces of 14-in. flat iron drilled to fit over the ends of the clamps. Common iron C-clamps, if large enough, or cabinetmaker’s hand-screws may be - used instead of the special clamps, but are not quite so convenient. The borders are made of veneers, which are thinly sliced or sawn sheets of wood. Various woods are used, such as holly, walnut, mahogany, vermilion (or paduk), satinwood, and ebony. These are sup- plemented with red, blue, green, and black dyed veneers. Ordinary veneers of various thicknesses can be purchased from some lumber dealers and practically all veneer factories; dyed veneers can be obtained from dealers in inlays. It is, of Ornamental units and borders built up by the method illustrated in the adjacent drawings course, a simple matter to dye white ve- neers any color with penetrating wood stains. Let the sheets dry thoroughly be- fore attempting to cut or glue them. To make a border such as shown in Fig. 4 of the accompanying drawing, take one piece of walnut 3/16 in. thick, 4 in. wide and 3 ft. long; one piece of white holly of the same dimensions, and one piece of redwood 1/30 by 4in. and the same length. Lay the white holly on the smooth side of one of the gluing blocks and apply freshly made cabinet glue or the best quality of liquid glue freely with a brush all over it. Place the red wood on top and apply glue on the upper side. Then lay the 3/16-in.. walnut strip on top, place the other “‘two by four” on top of all and clamp the whole together. After the glue has set for at least six hours, you are ready to cut up this 3-ply strip in a miter box. If you have no miter box, you can quickly make one of wood, because only a straight, square cut is needed. Tack a small piece on the base of the miter box one inch from the saw slot, so that you can cut quickly a number of pieces—say 27—each 1 in. long. Then move the stop and cut a similar number 5/16 in. long (Fig. 2). On one of the gluing blocks, lay a sheet of white holly 1/16 by 4 in. by 3 ft., coat (Continued on page 99) © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17. 4u et en TH wt RnR oc} A ot het et Be > — +! --+ 425 -—¢*§ 485 ~*~ ea oe me — DR = of a fs 2m ® rr | Se "s acted HQ0 8S" S6 4

Page 87

t, 1925

rhich rood. olly, luk), sup- and Ts of from y all n be is, of by ings @ ve- wood ly be- n Fig. e one wide lly of ce of ngth. 1 side apply best brush p and n lay place ll and st six 3-ply ve no me of re cut > base e saw imber Then umber sheet » coat

august, 1925

The Home Workshop Method of Making Inlays (Continued from page 98) with glue and place on it a piece of blue veneer 1/16 by 4 in. by 3 ft. Tack a small piece of any kind of wood across one end and against it place one of the 1-in.- long 3-ply pieces previously made. Against it lay one of the 5/16-in. pieces, taking care that the holly goes against the walnut, as shown in Fig. 3. This must, of course, be well glued to the 1-in. block and also to the blue veneer. Now lay another 3/16-in. piece, then a l-in. piece and so on until you have gone as far as you can. Tack a small strip tightly against the last piece so that the strips will not separate. Apply glue over the top, lay a strip of 1 /30-in. blue veneer next, and then another piece of 1/16-in. holly. Lay down the other “two by four” and clamp the whole together. Let this stand at Jeast eight hours. Al] you now have to do is to cut your block up lengthwise into strips. You can suit yourself in regard to thickness. As a rule, borders are cut 1/12-in. thi¢k, so that out of ‘this piece, if 3 ft. long, you will get about 66 ft. of inlay 14-in. wide. It is obvious that the same method can be used in making inlays of countless dif- ferent designs. By making some of the cuts at an angle, it is possible to introduce angular lines into the pattern, as shown in the photograph on page 98. In ex- actly the same way geometric inlays for the center of drawer fronts, table tops, radio cabinet ends, and similar uses can be made. O LAY a border, use a marking gage to mark lines in the correct location. Make them a trifle closer together than the width of the border. Draw a sharply ‘pointed knife over the lines, cutting them to a sufficient depth, and remove the wood with a small chisel. Do not make the groove as deep as the border, which should stand out a little when in place. Cut right-angle corners at 45 degrees in your miter box. Lay the border strips tightly with plenty of glue. After eight hours or more, the surface can be planed, scraped, and smoothed with fine sand- paper. If the piece is to be stained everywhere except the inlay, shellac the inlay first, so that any stain getting on it accidentally can be removed before it has a chance to penetrate. Apply wood filler if necessary, and then finish with shellae or varnish or both, rubbing the coats down with pum- iee-stone and finally with rotten-stone.

WHEN a varnish stain of a special or unusual color is required, it can be made by coloring a good grade of clear varnish with a strong solution of dye dissolved in turpentine or benzol. Strain the dye before adding it to the varnish, and do not add enough to make the varnish noticeably thin. If a very dark color is needed, it probably will be necessary to dissolve the dry stain direct- ly in the varnish, afterwards discarding any sediment.

POPULAR SCIENCE MONTHLY

it’s done. o j obs’”’ Mathias

No need to ask Fred— One twist with Klein pliers and At least a dozen little a week are like this—not jobs at all with a pair of Klein’s. For radio, auto and general use they’re indispensable. dealers have them, in various sizes. © MEEIN:

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\ © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. a Sut? Si it to your friends and ne as a sam — of our fine quality, hand-tailored All-Wool Suits, guaranteed | $40 valuesat amazing low price } of $23.50, take their orders, ii)|| keep handsome profit for your- self and send orders to us. oo eens Making | BIG MONEY $3.00 to $5.00 an hour in spare time, $75 to $150 a week for , full time. Wesupply handsome Swatch fies Out! large size samples and all latest stylesin elegant Leather Case. Positively finest selling outfit ever furnished salesmen. Write for porns atonce, pick out your suit and get started making the Big Money rightaway. Address Dept. {30 AMES OLIVER, Inc. 848 W. Adams Street Chicago Write name and address below and mail at once.

POMP O POOR HOH eee wero eee eeeeeeeeessseseeseee®e See page 17.

Page 88

August, 192". , Augus 100 POPULAR SCIENCE MONTHLY Must we revise| Bu tam Conte 5 hop] Ti our package | Rounding a Board’s Edges By Emanuel E. Ericson, Noted Manual-Training Authority ero | how slips? a Se 1 Thumb gaging. Use a fairly join hard pencil with a sharp, slender * | pen In the larger s'zes of Edgeworth contain- | Point. Draw a line on both sides to T ers we have long been in the habit of og a vices one aiale e: - : ‘ ; 0 enclosing a slip or card, bearing the follow- of the edge to serve as a guide when ride ing invitation: planing. These lines should not be re- The moved until the last operation of all 2b Thank you! As a user of Edge- hs worth’ tobacco, we are sure you | the appreciate its merits, which have met won for it a Distinction among Ins Extra High Grade products. it is May we not ask you to urge your filli friends who are not smokers of pro Edgeworth to give it a trial. You the may use ‘the other side of this wal card. Thank you. . if: a] L &B Cc 2 Planing. Hold your wi wanes ha jack plane at a slight for — angle if the bottom is are Mr. Newman returns a slip to us with this a oe ae corrugated. Tilt the plane ove notation: with each stroke to pre- In vent making a flat bevel jan Mistrese: Mess: on the board. Coarse she Larus & Bro. Co., Richmond, Va. Gentlemen: My friends all use Edgeworth, showing that I select men of good judgment for my flo: friends. I have smoked your tobacco for . — eee shavings may be taken at first, then finer ones twenty-five years. _ ing Yours appreciatively, wh B. S. Newman. b y The question is, shall we change the word- se ing from ‘‘friends’”’ to fb —— “acquaintances” on ‘ our container slips, or w how shall we avoid be- jo} ing “called” by other pl club members? nl 2 tae Fi Let us send you free is nya , samples of Edgeworth in Bs nai 2 so that you may put it pe ee aga 4 Filing corner. The corner is 10 ples, you'll like smoothed with a fine wood file Al d ‘ gen cong (not a rasp) after the planing and — ee chiseling are done. File on the dr 5 sceli ushing stroke and lift the file com- ever you buy it, 3 _ papas Boreas > gp tonsa si sen The file is not used on - for it never] uftace is best removed with a chisel. the straight edges, but it is an |. ro changes in qual- The principle is the same as with the plane invaluable woodworking tool for * ity. Write your | on the straight edge. Have youn chisel finishing curved surfaces and shapes R name and ad- as keen as oilstone and leather by dress to Larus & | _ strop can make it. If the curve ; F Brother Company, 10 H South 21st Street, is large, a spokeshave is used Ww: Richmond, Va. su Edgeworth is sold in various sizes to si suit the needs and means of all purchasers. Ww Both Edgeworth Plug Stice and Edgeworth Ww Ready-Rubbed are packed in small, pocket- he size packages, in handsome humidors hold- fc ing a pound, and also in several handy in- b between sizes. ft We'll be grateful for the name and ad- li dress of your tobacco dealer, too, if you : care to add them. ; To Retail Tobacco Merchants: If your n jobber cannot supply you with Edgeworth, | n Larus & Brother Company will gladly send | L — iV abe nae’. » benno emcee hana Plug 5 Tear sandpaper with the 6 The sandpaper is held over a soft wooden r : rough side up over the block. Change the angle with each stroke Slice or Edgeworth Ready-Rubbed for the ME h 4 EP regener th ss Shacrantitaien bene same price you would pay the jobber. ench corner or any sharp edge a ot work over the pencil line u e E © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17.

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h. August, 1925 The Home Workshop A Child’s Playhouse (Continued from page 75) however, to make a small door, using either doweled or mortise-and-tenon joints, or even butt joints nailed with 20- penny finishing nails. The framework is made almost entirely of rough 2 by 3’s and 2 by 4’s except the floor joists, which are 2 by 6, and the ridge, which is either 2 by 6 or 1 by 6. The floor beams are notched to take the 2 by 4 in. sills and then laid directly on the ground and carefully leveled. The method of framing is shown in detail. In some places, as alongside the windows, it is necessary to nail 1 by 3 or 1 by 2 in. provide an edge against which to nail the wallboard, if the application of the fore the inside door and window facings are nailed in place, so that the latter go over the rough edges of the wallboard. In that case, the window and door jambs will have to be made wider than shown by the thickness of the wallboard. past of all, the baseboard should be nailed against the wallboard at the floor line. If the joints between the ceil- ing.and the wall in the corners or else- where are not tight, they can be concealed by \%-in. quarter-round molding or any flat strips such as can be made by ripping lattice lath in half. It is so easy to cut fiber wallboard cleanly and accurately with a fine saw or a sharp penknife, and joints can be made so neatly, that in a playhouse of this kind no covering strips or moldings are really necessary. The lumber required for the framework is 175 lin. ft. 2 by 3 in., 200 lin. ft. 2 by 4 in., 100 lin. ft. % by 2 or % by 3 in., 7 pes. 2 by 6 in. by 6 ft. for floor joists, and 100 lin. ft. 34 by 10 in. roofing boards. All this is rough lumber. For the walls, 275 lin. ft. of 34 by 6 in. drop siding is needed; for the roof, 3 bundles of wooden shingles, laid 4 in. to the weather. Composition shingles or roll roofing can be used, if preferred. Regular tongue-and-groove flooring % by 24 in. is used, 65 sq. ft. being required. For the inside walls, 200 sq. ft. of fiber wallboard is ample. The finishing lumber, which should’ be surfaced on four sides, will vary con- siderably, according to the number of windows and the closeness with which the work approximates the trim in a real house. If.the house is made as shown, the following will be required: 100 lin. ft. % by 214 in.; 60 lin. ft. 7% by 3 in.; 100 lin. ft. % by 4 in.; 60 lin. ft. 7% by 5 in.; 20 lin. ft. 2 by 6 in., for making window-sills (or regular window-sill stock); 1 pc. 1% by 6 in. by 2 ft., preferably hard wood, for door-sill; 30 ft. 7% by 13% in. water-table molding. One roll of building paper, nails, hinges, door-lock: set, paint, and varnish, also are required. If the sash and door are not purchased ‘as a sheet of plywood and window-glass. filling pieces to the studs in order to | wallboard is left to the very last. The wallboard can, however, be applied be- ready made, sufficient 13¢-in. stock is | needed for their rails and stiles, as well | facts—just what you want to know about advertising. Write today: © This seal on a radio or tool advertisement dedi: the approval of the INSTITUTE OF STANDARDS. POPULAR SCIENCE MONTHLY ; 101 The hottest thing under the sun Engineers devised a minia- ture “crater.” Electric energy, passing through the gas which it contains, makes it considerably hotter than the crater of Vesuvius. Such unusual achievements in elec- tric lighting are among the practical accomplishments of illuminating engineers —the experts of your own electric light and power company and of the General Elec- tric Company. They have made electricity for light and power actually cheaper than it was before the war. Is this merely a laboratory experiment? Not at all. This tremendous heat and light is safely used in searchlights and in motion picture pro- jectors, where it contributes to the pleasure and education of millions. | GENERAL ELECTRIC COPY THIS SKETCH and let me see what you an do with it. Cartoonists trained this school are earning from $30.00 to $200.00 or more per week. The Landon Picture Chart Method of teaching makes original drawing easy to learn at home in spare time. Send sketch with 6c in stamps for sample chart to test your ability and long list of successful students. Please state a ii DON SCHOOL TUBE SPEAKING - GUARANTEED Loxe Diy TANCE! 1451 National Bldgs CLEVELAND, 0. ‘ gvorywhere teport Miraco equency. sete ‘Bet reannene coast toc er- orm sets 3 times as co tty. nd for proof they are radio s most amazing values. ues tube teed, completely assembled tong distance ome only$i4. 35. Three tube(above),$29.50.Five tube $75 EAy + ¥.00) (6 al se ND POSTAL TODAY > for latest bulletins and special el ag S E M offer. It will interest you. 7 MIDWEST RADIO cORP’N [&6):- Rete 408-P. Broth Ste Ciadnnatt, Ohio ASO). ta 3 { = ee ee dt; Advertising men are among highest paid m the world. You can learn ea-ily and quickly at home during your spare time. Bigger oppor- tunities now in She Pe — ever before. Tremendous | demand or our graduates B big p: for FREE Book. “Giving interesting information and vital PAGE-DAVIS SCHOOL OF ADVERTISING, | Dept. 136-C 3601 Michigan Ave., Chicago, U. S. A. See page 17,

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102 The Letter That Saved Bob Johnson’s Job —and paved the way for a better one! T WAS written to his employer by the International Correspondence Schools. It told how “Robert Johnson had enrolled for a course of home¢study and had received a mark of 94 for his first lesson.” Bob answered the summons to the Chief’s office with just a little fear and trembling, for a lot of men were being dropped—a lot more were having their pay reduced. But as Bob came in, his employer did a surprising thing. He got up from his desk and grasped Bob by the hand. “I want to congratulate you, young man, on the marks-you are making with the I. C. S. I am glad to see that you are training yourself not only for your present job, but for the job ahead. “We're cutting the pay-roll. Until I received this letter, I had you in mind as one of the men to be dropped. But not now. Keep on studying—keep your eyes open—and pretty soon there'll be a still better job for you around here. We're always looking for trained men.” Won’t you let the I. C. S. help you too? Won’t you trade a few hours of your spare time for a good job, a good salary and the comforts that go with it? Then mark the work you like best in the coupon and mail it to Scranton today. That doesn’t obligate you in the least, but it will be your first step toward success. Mail the Coupon for Free Booklet ““ INTERNATIONAL CORRESPONDENCE SCHOOLS — Box 7661-D, Scranton, Penna. me a ahi, 2 Ele Ss which I have marked an X: BUSINESS TRAINING COURSES pv nao ve ee Card Lettering ow Ca: - itenography and and Banking Law Business a (including C.P.A,) 1 Service Accounting Railway Mail mon School Subjects High School Subjects French ‘ TECHNICAL AND INDUSTRIAL COURSES Engineering Architect tric Lightin Architects’ Blue Prints Mec! 1 Seater Contractor and Builder hanical Draftsman Architectural Draftsman hine ~ Practice Concrete Builder iroad Positions Structural Engineer Engine Operating Chemistry () Pharmacy Civil Engineer Automobile Work Metaburey (Mink Agriculture and Poul Bioum Sneioering Chisato AiMednatics = tt? TE eiaddviiabimascsbasunbdtehndassctabinbecessthesscuteetomeennenescoreceeeses Street 3-6-24 City State. Pavone revtfing Canede cheuké cond ste sougen é she international Correspondence Schools Oanadien, Limited, Montreal, Canada POPULAR SCIENCE MONTHLY August, 1995 of By F. J. Wilhelm OE, just starting to drill a lot of brass castings, had progressed no farther than h& first hole when there was a clatter and a bang. The small casting, which he had been holding @ by hand on the drill- press table, broke from his grip. It prop spun around — STEEL violently. Before he could stop the © ae SLOTTED istic Monday morn- = ing start for Joe. His foreman, who was making his early rounds, saw the mishap and inquired why Joe hadn’t clamped the job on the table. ; “Well,” Joe explained glibly, “‘I thought it would take extra time and I tried to hold the casting with my hand. It went all right until the drill started to go through. It jumped so quick I couldn’t hold it and it got away from me.” “Let me see the drill you were using.” The foreman glanced at the cutting edge. ‘‘Get another drill,” he said, ‘‘and I'll show you how to grind it for brass.” Joe brought another drill from the crib, the foreman stepped over to the emery wheel, touched up the edge and handed the drill back to Joe. “You will see that I have ground the cutting edge flat; that is the way a drill should be for brass or bronze. You can’t cut these metals like stee] or iron. They have to be broken up and that is just what the flat edge is for—and to prevent the drill from digging in. Try that now and I don’t think you will have any further trouble. But use a clamp on the job.” Figure 1 shows how the drill was ground. Most men think of a drill press as a machine simply for drilling holes, yet a drill press is a close rival of the lathe in doing stunts. Like the stunts per- formed by a circus elephant, many of them seem incongruous, but they are Better Shop Methods (Continued from page 82) How to Make the Most spindle, the drill TAPER TO FIT and water. Only snapped and the TAPER SPINDLE j @ light pressure casting bounced FITS DRILL’ 4.58 is needed to cut a away. A character- BRASS LAP —_— clean hole through —. Your Drill Press useful in many small jobbing shops and even in.some of .the large manufacturing plants where a drill press occasionally will be rigged up for some special job for which it never was intended. Lapping holes in hardened-steel dies and in engine cylinders may be done in the drill press. Two forms of laps, Figs. 2 and 3, are useful. It is even possible to do some kinds of work with a lap made by wrapping a piece of emery cloth around a stick (Fig. 14). A rough-and-ready substitute for a die- filing machine for dies having circular contours or round corners is a drill press with a piece of round file in the chuck (Fig. 18). To cut large circular holes in plate glass requires nothing more than a short steel shank with a wooden plug on one end and a piece of m, TAPER TO FIT Ey NUT brass tubing (Fig. 15). The plug oneaed fits snugly inside the brass tube, is charged with emery the glass without chipping the edges. Figures7,8, and 9 are suggestive of how a (Continued on page 103) > SSV//1I/7 BY S e}\ S SHUG Git S SETTINGA THREADED Fin “== Methods of using a drill press for special pur- poses, when the shop equipment is limited © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS, ~See page 17. frict for opel scre L (Fig is 1 spin T fron rela mac

Page 91

and ring ally job dies e in ‘igs. sible lap nery die- ular ress Auck slate hort th a 2 of (Fig. aside s; is mery Only ure ut a ough hout iges. 9are OW a > 103) pur- ited

[Better Shop Methods

How to Make the Most of Your Drill Press (Continued from page 102) friction drive drill press may be used for assembling small parts. Among these operations are driving small studs and screws, and spinning rivets, as in Fig. 10. Light broaching operations are feasible (Fig. 4) if a broach of conventional type is made with a shank to fit the chuck or spindle. Two methods of cutting washers from rubber, felt, fiber, and similar relatively soft materials are indicated in Figs. 5 and 6. Tapping holes with a drill press is made easier if a center punch is pressed

PIECEOF W ROUND FILE}

LLL Using a drill press for boring, filing, grinding, lap ping, tapping, drilling glass, and making springs

against the end of the tap, as in Fig. 17, while the tap is turned with the wrench. This insures starting the thread squarely with the hole and lessens the danger of breaking the tap. A simple method for locking cutters in a har for spot facing and counterboring is shown in Fig. 11. Figure 16 suggests a method of using a small hand grinder in connection with a drill press. When a spring is needed in a hurry and all the lathes are busy, it is possible to grip the spring arbor in a drill chuck, as shown in Fig. 18. Start the wire in the usual manner and guide the pitch of the spring by hand. How a box-turning tool may be adapted for use on a drill press is indicated in Fig. 12. _ These all are ideas I have used at one time or another and have taught to many young machinists like Joe, who are not apt to appreciate fully the capabili- ties of a good drill press. POPULAR SCIENCE MONTHLY “The World’s General Utility Tools” E-F Angle Screw Driver and an EF EL-FLASH. P JERENCH NCH Kir

AU

A Master Tool Kit That Fits Your Pocket —Everywhere. The Universal PlieRench For every kind of Pliers, Nut Wrench, Vise, Clamp, and Spring-making Work For Your RADIO - CAR - SHOP - HOME - FARM, Etc.

The Wire PlieRench For every kind of Wire Tire Chain, Cable an Spring Work; and the Special work other Tools won’t do. The Pipe PlieRench For every kind of Pi Wrench and Pliers Work; Chewed Nuts that no other tools can budge,etc. Only 4 Years Young; but helped to win the FIRST WORLD FLIGHT— Wim eacn ur GRIP NT INSTANTLY CHANGEABLE OPERATING JAWS, making it instantly CONVERTIBLE—FOR EVERY TOOL USE—EVERYWHERE! Size 8) inch. Read below what Major F.L. Martin, the Flight Comman- der at the start of the — Ts Guamen. S60 So sey spect ee TEED TO DO THE WORK of 60 <‘Gentlemen: In re

Rly to your A VALUABLE BOOK Ask the U. S. Army WORLD FLYERS who refused a $15 offer for one. oe A PARALLEL PLIERS that IS a REAL WRENCH—It has 2 ONE-TON POWER-CEAR PRESSURE oe x h i ith natural automatic and release; INSTANT RATCHET JAW ADJUSMENT 0" to 125", Handles ALWAYS FIT your hand. THREE estore

1 f July 21, wi h of, POUNDS of the dedi ot cos World Flight for—in this, UNI- 4 er Tools, ha as a part of its equipment SAL Kae to a PlieRench Kit. Tot I KIT 7 aqeies tS rma cats hig e 2) i) POUNDS! and every Airplane snd Auto- (1) GOOD TOOL. eee Yours truly, (8-11-24) E. L. Martin.” The E-F ANGLE Screwdriver has 7 working edges, or SS blades, and does the work of many Screwdrivers—large

oe = cr seer The ANGLE BLADES work under obstructions where ordi- nary Screwdrivers are useless. You'll soon regard it as an in- dispensable necessity.

MAIL this COUPON in TODAY ! And get the $5.00 KIT at the New, Low, “Give-em-Away” Prices shown—then, if not sure it will be WORTH $25.00 TO YOU—return it within 2 weeks and get your money back. . 4F YOU SELL—MARK \COUPON for PROPOSITION and small and angle; yet it weighs only }4-oz., and fits a key-ring and a keytainer. Size 234 inches long. It removes caps and corks from bottles and does number- less other useful things. Made of finest Crucible Spring Steel, hardened and tempered throughout—it will handle

9 Surprisingly THEFLASH.SALES CORPN HEAVY Work. JOSEPH EIFEL, Gen. MANAGER Ie ‘saves costly Dept. es eee Te eaten m. Knife Blades. RP’'N Dee ea a 4000 Ne. Ashland Ave., Chicago, © @eaaeasaa a id in U.S. A.—Items “X”” enieniiiads tse CO. D. I ENCLOSE— 2 PlieRench KITS, 2Screwdrivers 0 $7.95 O Ck.;M.0.; $7.75 1 of same : Gee. G27; See « 4E-F ANGLE Screwdrivers only ........-- O Stmps. Coin $0.50 2 of same 3 ae ** $0.80 FREE Literature, etc.—O For Tool Users; 0 For Distributors

EasytoDraw Cartoons When Shown in the RIGHT WAY

— to limber up stiff leg_muscles. For thelame shoulder. For insect bites. To guard against infection

Some of the cleverest cartoonists and comic artists learned how to draw in their spare time by followin: Cartoonist Evans’ Simple and Easy to Learn Metho and are now MAKING GOOD MONEY. Send one of your drawings, and let Mr. Evans see if 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 825 Leader Building Cleveland, Ohic

from cuts and bruises. For after- pie “d shaving comfort(dilute).For plant poisoning. For sunburn. $1.25 at your druggist’s W. F. YOUNG Ine., Springfield,

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17.

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POPULAR SCIENCE MONTHLY August, 1925

The Home of Your Dreams **Ready Cut”’ $ 1213 **Sectional’”’ 2205 F. O. B. Brooklyn HE “Piping Rock,’’ a Bossert Bungalow Model, is famous throughout the country as the Blue Ribbon winner among bunga- lows. As an all year-round home, guest house or summer bungalow, the Piping Rock isideal. This charmingly designed home has large comfortable living-room, 18 x 9 ft; 2 light and airy bedrooms, 12 x 9 ft; kitchen 6 x9 ft. and bath 6 x9ft. A pergola pro- vided on each end of the living-room further serves to enhance the beauty of the Piping Rock. Each bedroom has a window on three sides. The living-room has casement doors at each end opening on the pergola, and 2 front windows. Pierced panel shutters on all windows. This bungalow is built of the best ma- terials at the huge 32 acre Bossert plant and is guaranteed to give complete satisfaction. The “Piping Rock’’ is delivered to you either ‘“‘sectional’”’ or ‘‘ready cut” as you desire, complete with plans and specifications for erection. : Send your order today, or write at once for catalogue showing this and many other attractively designed Bossert models. LOUIS BOSSERT & SONS, Inc. “Largest Lumber Plant in the East’’ 1310 Grand St., (House Dept.) Brooklyn, N.Y. Tests Show Ford Can Run 41.4 Miles On Gallon of Gas The amazing fact that a Ford can run 41.4 miles 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 426-1200 Eleventh street, Milwaukee, Wisconsin.

CORONA FOUR With standard office keyboard—an office typewriter in port- _¢ able form. G Write for literature.

Better Sho New Lathe Tools Have Long Life ups in gangs of two or more tools in turret work, a British engineering company has developed the circular lathe tool illustrated below. The design of the tool is simplicity itself. It consists of a body holder provided with a circular cut- ter, which is symmetrical in shape and can be produced by turning. Aside from the special cutting qualities claimed for it, the tool has the additional advantages of economy in the use of high-speed steel and a decrease in power consumption, a considerable increase in production, lower toolroom costs, and ease in handling and grinding. As the tool can be rotated in the holder, any part of its circumference can be brought into use, as the clearance angle is uniform. For this reason it is said to have a much longer life between grindings than tools of rectangular shape. The efficiency of this tool in comparison with an ordinary round-nosed tool was tested on a light cut \% in. deep witha % in. feed. The speed of cutting was 115 ft. a minute, using a cooling compound, on a belt-driven lathe. The round-nosed tool failed after traversing the first 12 in. and was unfit for further use without regrind- ing. It was noted also that the speed of the lathe was reduced by the resistance of cutting from 115 ft. to 75 ft. a minute. In the case of the circular cutter working under exactly the same conditions, a dis- | NOR plain turning and for special set-

The circular cutter in its holder, a cutter — blank and a fixture for regrinding cutters tance of 12 ft. was traveled by the tool without any noticeable reduction in the cutting speed. The tools are sharpened only on the top and this is accomplished in a special chuck or fixture on a surface grinder. As the tool wears and is ground down, it can be packed up with suitable rings.

Hand-Operated Slide for Small Milling Operations

rok numerous small slotting operations on screws, bushings, and similar work, a simple hand-operated slide adapted for use on an ordinary milling machine is exceedingly useful. The accompanying photograph shows one that is used regu- larly on a flat turret for slotting a screw. The base of the slide is bolted to the platen of the miller, and the slide is re- ciprocated by means of the lever attached to the pinion-gear shaft. The slide is rack-cut a sufficient length to allow the necessary movement. - The drawing shows the construction of a simple fixture for holding a special type of screw D for slotting in four positions, on the quarters. The block JA is held in the tool-pocket of the slide by a setscrew. Bushing B is knurled on its enlarged diam- eter or shoulder for hand manipulation in indexing for the four positions. Bush- ing C is split in half so that it will separate readily to release the screw, which it holds in slotting. A flipper pin E, spring F, and screw G serve to retain and locks bushing B in holder A, and bushing B is

{ \\ ER ; NK <= \Y A 1 WN \E J \— \ J y AY wa

i WA AN 4 Y Indexing fixture for repetition work with the reciprocating slide shown at the left

spotted in four places for the index. Screw H binds bushing C during the cutting operation. A stop screw is provided ‘in the cut-off slide to control the length of stroke. With the machine table set in a conven- ient position, a simple motion of the slide lever only is necessary for light work of the kind shown.—O. S. MARSHALL.

TOOL steel can be annealed with water. Heat the piece slowly to a dark red, take it out of the fire and hold in the air until all the color has disappeared. Test with a match-stick or any piece of soft wood. If the wood does not smoke, the steel can be dipped into cold water.

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17.

wa shunt

la. wZ

Page 93

> tool n the e top chuck s the an be 3ush- arate ch it pring lock B igs or wa dex. the t-off oke. ven- the ight ALL. iter. red, > air Test soft the

» .

‘| stead of oil. | quickest way to do August, 1925: ——$—$—_—— POPULAR SCIENCE MONTHLY erin tod 105

— Old Bill Says— when you start a new job; remem- ‘per this and after you have fin- ished, wipe up the machine for the next man. When drilling yery hard steel, use turpentine in- Yu like to find a clean machine Try to find the everything; it makes your work like a game in which you always are matching your wits against

| a problem. Old Bill, machine- Oil costs money shop foreman and should be put in the oil hole or cup where it belongs— not spilt over the outside of the machine. Some one always pays for our blun- ders, if not in cash, then in conse- quences. Loose sleeves have caused many a broken arm—play safe! é; Beware a constant borrower !

How to Construct a Sine Bar for Large Angular Work "DIA. X 1/2" LONG BAR I"X1/4"X12" a A 9°

CAST IRON S (CORED OUT) HIS sine bar for obtaining angles accurately is of especially heavy con- struction. It can be adjusted quickly and will hold its setting. The angle plate is made in two sections held together with dowels and screws. The pieces are ground on all sides before they are assembled. The T-slots in the vertical plate allow the sine bar to be used on either side, thus providing a wide range of adjustment.— H. L. WHEELER.

Rhus blame the weather for all sum- mer radio troubles. . . . How are the tubes? All tubes, remember, grow weak with use—especially in summer when operated at higher voltage. Bring them back to full efficiency—right in yourown home—with the Jefferson Tube Rejuve- nator! Takes only 10 minutes; attach toa convenient electric light socket. Com- pletely restores paralyzed or exhausted tubes. Used once a month, it DOUBLES and Trestes the life of tubes! Quickly pays for itself in saving of tubes and bat- teries. A home rejuvenator for tubes is just as essential to satisfactory radio re- ception as a charger for storage batteries. Jefferson Rejuvenator takeslarge or small tubes—201-A, 301-A, UV-199, C-299. Fully guaranteed. At leading stores sell- ing radio supplies. If your dealer can’t supply you, send $7.50 to JEFFERSON ELECTRIC MFG. CO. 501 So. Green St., Chicago, Ill. Makers of Jefferson Radio, Bell Ringing and Toy Transformers; Jefferson Spar Coils for Automobile, Stationary and Marine Engines; Jefferson Oil Burner Ig- nition Coils and Transformers,

For Good Summer Radio Reception use | JEFFERSON TUBE REJUVENATOR keeps tubes like NEW!

YErreRs On REJuve: te NATOR

A new oe lebcap ine less than 1¢ Dent throw the old one away because it works loose. Paint the threads with Smooth-On No. 1 and reset, and it won’t move again until intentionally taken off. ~ It pays to make one job of overhauling all the grease cups, caps and lock nuts in the same way. _ Smooth-On No. 1 being impervious alike to water, oil, gasoline or heat, is also the best thing for stopping leaks at radiator hose con- nections, gas and oil line joints, and exhaust pipe connections. ‘ithe der _ Get Smooth-On No. 1 FREE BOOK | in 7-oz. or 1 or 5 lb. can from your supply house. $00,000 Offices

Page 94

a8: r Nae bj | “If I Just Had Bill’s Snap-On Set— I could fix it and be on my way in no time—but my monkéy wrench won’t reach it—my others either won’t reach or won’t fit. what the tow-in will cost? how long it will take?” Now, “Bill” is his favorite garage mechanic—one of more than 250,000 repair men using Snap-On Wrenches. A few Snap-On Units correctly se- lected from Bill’s Master Set, is all that this car owner needs to help him out of every such annoying road emergency. Wonder Wonder. POPULAR SCIENCE MONTHLY

| Any Snap-On dealer can select the | few correct Snap-Ons needed for complete repair work on any make of car, or the one Snap-On Wrench required for any particular job. Are your tools offering you real pro- | tection on the road and cutting the cost of upkeep for you? Learn what Snap-Ons will do for you. If your dealer cannot show you the correct | Snap-On Set for your car, mail the coupon. Snap-On Wrenches are made only by the SNAP-ON WRENCH COMPANY Itis not a genuine Snap-On unless so stamped. » Snap-on INTERCHANGEABLE, Socket Wrenches Motor Tool Specialty Co., 14 E. Jackson Bivd., CHICAGO Gentlemen: Please send me full particulars about Snap-On Kit for ({f interested in Master I buy tools from RE atin dhicwnt de seashs Se aaseps|

CORE ry PRINT }.__tl4! - al 6-¢— 6-0" z

A costly special flask instead of an ordinary one was required for casting this pattern be made at a cost of $120 to mold the pat- tern on its edge, as in the side view, Fig. 1. Was that expense and trouble neces- sary? Absolutely no. A slight change in the design, which in no way would have | affected the strength or the purpose for which the casting was to be used, would have made possible the molding of the | pattern on its side. / ‘mon saying among foundrymen. How-

The superintendent and his foundry foreman ask an expert’s opinion on a big pattern ‘“*A good molder can mold any pattern’ provided it has‘two ends onit,’ ”’ is a com- ever, cooperation in the drafting-room, the pattern-shop, and the foundry, and ani} occasional visit to these departments by) f the draftsman will give him a _ better} understanding of how the work is done and will suggest ways in which he can} use this information to his own advantage} and to the interest of the company. Hey} will be better able to make drawings thati answer the requirements of both patterns ‘ maker and molder without sacrificing q strength or design.

THIS is the last article written for} POPULAR SCIENCE MONTHLY by Mr.| Duggan, who was regarded for at least } a quarter of a century before his death} as one of the foremost pattern-makers | in the United States. In this message to mechanics he emphasizes again a theme that he believed to be of the ut-' most importance in every shop. He held that every mechanic and, of course, every engineer, designer, and drafts- man, should make a determined effort to understand the other fellow’s prob- lems. Only through such understand- ing is real cooperation possible. It is true that in this article he points out a defect and does little more than intimate the remedy—the redesigning of the casting. Probably the casting could not have been redesigned without the making of an entirely new pattern at a cost in excess of the building of the special flask. Perhaps, too, the element of time was exceedingly important, as it so often is, and the superintendent} felt obliged to get the casting made without delay at any cost. But no shop- man can fail to agree in Mr. Duggan’s fundamental proposition, that the more we appreciate the problems and the difficulties of the other fellow’s job, the better we can do our own.

advertisement signifies the approval of the INSTITUTE OF STANDARDS, See page 17.

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New York Office Suite 1007 Woolworth Bldg. Philadelphia, Pa., Office Suite 714-715 Liberty Bldg. 3 ie Washington, D. C., Office Victor Bldg. POPULAR SCIENCE MONTHLY. TRADE-MARKS| COPYRIGHTS OUR OFFER: Your first step Uf Before disclosing an invention the invéntor should write for our blank form “‘RECORD OF INVENTION.” This should be signed, witnessed and returned to us together with model or sketch and description of the inven- tion 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 Full instructions regarding U. S. Patents. 4 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 ALL COMMUNICATIONS AND DATA STRICTLY CONFIDENTIAL INTERFERENCE AND INFRINGEMENT SUITS PROSECUTED Private Office, Victor J. Evans, with View of Patent Office Through Window ee ren eeepc aee ighest References Prompt Attention Reasonable Terms VICTOR J. EVANS & CO., Patent Attorneys | i Main Offices: 760-9th Street, N. W,, Washington, D, C, j Gentlemen: Please send me FREE OF CHARGE your ; F; REE books as described above. . Ng cs iy ni neginnns hwene + qedemstnee eenesadineemensians 1 | NNR Cire et Se Cane etude alse atele Wide cteaialaisre Mime sboe.sacicnwaleee IS] This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17. Chicago, IIl., Office Suite 1114 Tacoma Bldg. Se Pittsburgh, Pa., Office Suite 514, Empire Bldg. Pee eee mE ca ; | San Francisco, Cal., Office Suite 1010 Hobart Bldg. ence

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ro School ai He ad * 3 & i aren nt Se ieaenrsrpe ears! COURSE IN TWO YEARS YOU ARE BADLY if you lack HANDICAPPED Hi2hSchool training. You cannot attain business or social prominence. You are barred from a successful business career, from the leading professions, from well- paid civil service jobs, from teaching and college entrance. In fact, em- ployers of practically all worth-while positions demand High School train- ing. You can’t hope to succeed in the face of this handicap. But you can remove it. Let the American School help you. FIT YOURSELF FOR A BIG FUTURE This course, which has been prepared by some of America’s leading professors, will broaden your mind, and make you keen, alert and capable. It is com- plete, simplified and up-to-date. It covers all subjects given in a resident school and meets all requirements of a High School training. From the first lesson to the last you are care- fully examined and coached. USE SPARE TIMEONLY Most people tdle away fifty hours a week. Probably you do. Use only one-fifth of your wasted hours for study and you can remove your present handicap within two years. You will enjoy the lessons and the knowledge you will gain will well repay the time spent in study. Check and mail the coupon NOW for full particulars and Free Bulletin, American School Dept. H.C. 75 Drexel Ave. and 38th Si., Chicago GRE SS AE A Ge Ce EE A A Se American School . H.C.75 Drexel Ave. & 58th St., Chicago Send me full information on the subject checked and how you will help me win Say POPULAR SCIENCE MONTHLY August, 1935 New Clearance Gage Aids in Grinding Milling Cutters a AID in grinding the correct angle of clearance in milling cutters, the gage illustrated above recently was per- fected. The V-shaped body is placed over the cutter and holds the gaging blade in correct relation to the center line. The cutter is revolved sufficiently to bring the face of a tooth in contact with the blade, whereupon the angle of the clearance in the tooth should correspond with the angle of the gage. The gage serves for ‘both right- and left-hand cutters and for end-mills of all styles from 14 to 8 in. Cross Brace Prevents Gear Puller from Slipping abet for heavy duty, this convenient and substantial gear puller has a wide range of adjustment and is provided with a brace that pre~ , vents the spread- ing of the jaws whenever that might be likely to happen on diffi- cult and awkward work. The elon- gated slots in the horizontal and vertical members 24> SLOT | cp Oe=Op e: Ye" DIA. } 13 THD. USS ne" ee 7 7 NS y The gear puller in use, showing applica- tion of cross brace, and details of the tool SECTION SHOWING SLOT will allow quick adjustments; to be made. To make one of these pullers requires little machine work except drilling and tapping.— Harry M. CORNWELL. Better Shop Methods| Micrometer for Setting Boring-Bar Cutters bY bata setting the cutters of revoly.- ing boring bars it is desirable to have some method of accurately determin. ing the projection of the cutter from the bar. The accompanying _ illustrations show a micrometer devised by the write for this purpose. The upper view is the assembled de. vice. A standard 1-in. micrometer head is mounted in a clamp that has two prongs or forked points. When the micrometer reading is .000, the three points are jn line. Therefore, if the two outside points crometer adjusted until the moval anvil just touches the cutter, the ex projection of the ¢utter will be show The size it will cut then is determig readily as the sum of the project of the cutter and one-half the diameters the bar will be the radius of the holetagy In the lower view the constructiqggg? the forked clamp is shown. Theé body made of 11/16-in. cold-rolled steel, the twe prongs of 14-in. cold-rolled steel, and the clamping lugs of mild steel. all are welded together and finished j shown. A clamping screw with milled het is provided to hold the forked clamp @ the micrometer head.—EDWIN KILBUM Two Motors Drive Sturdy New Valve-Refacing Machine ae re es oe SR, aS Se REE SEES we N THIS new valve-refacing machine a conspicuous and valuable feature is the use of two electric motors instead of one. While one of them drives the grind- ing wheel at 3450 revolutions a minute, the other operates the work spindle through a gear reduction at a speed of 430 revolutions. The valve is held by means of a collet. Three sizes of collets, to suit practically all auto valves, are provided. These parts © This seal on a radio or tocl advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17. vi — - es et oF ODO _—ese tat ot TD a eee a ee

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Ust, 1995 ‘evoly- ble to ermin- m the ‘ations Writer ed de. r head prongs meter are in August, 1925 Factory -Made Vegetables Our Future Food? (Continued from page 21) “Possession of the ultra-violet ray is the thing that has made it possible for us to succeed where previous generations have failed. For a long time there has been theoretical knowledge that the res- toration of energy could be reproduced within our laboratories by the use of high temperatures, but from a practical stand- point the thing is impossible, for the rea- gon that the very heat that could produce the delicate structure also would inevit- ably destroy them. “The ultra-violet ray, on the other hand, has the same property of promoting anti-combustional changes as has heat and with the added advantage that it is not destructive. “Under the influence of the ultra-violet rays, water vapor and carbonic acid gas are decomposed. The water vapor di- vides into hydrogen and oxygen and the carbonic gas takes the form of oxygen and oxide of carbon. eC eeDING along these lines,’ hyde, the simplest of the ternary forma- tions, or sugars. This comes from the combination of oxygen, hydrogen, and carbon. “Going one step further, we accomplish the light synthesis of four elements—car- bon, oxygen, hydrogen, and nitrogen. This gives us the lowest quaternary form, the starch called ‘formiamide.’ “In other words, we have thus pro- duced both sugar and starch from the elements without the living organisms. The low form of albu- minoid starch is the beginning of the albu- minoids or proteins, and is therefore the base of protoplasms and of living matter.” Toscientists, this result of the Berthelot experiments is revolutionary—it is a step toward the possible laboratory produc- tion of at least one cqnstituent of the liv- ing cell and may aid materially in the dream of all scientists, the production of life itself! “Chlorophyll is the basis of our results,” said the scientist, continuing his explana- tion. “This material is the essential ele- ment of plant life. It is the thing that gives vegetation its coloring of green. The green pigments enable plants to utilize the light energy of the sun for transforming the atmospheric carbon into a higher chemical. Chlorophyll makes life possible. By reproducing the funda- mental reactions of the chlorophyll, we are able to create the sugars and starches pertaining to plant structure. =: HE ultra-violet light, therefore, per- mits us to realize, without living matter, but in Jiving form, the same syn- thesis as that of the plants. In subjecting aqueous vapor and carbonic acid mixture to the rays, by means of a mercury-vapor lamp, I have proved that these two gases combine to give the principal sugars exactly like those of plants. These ex- periments conducted with M. Gaudechon, show that by means of light, vegetable foods can be manufactured from air gases. Professor Berthelot went on, ‘“‘we | realize the Jight synthesis of formic alde- | intervention of POPULAR SCIENCE MONTHLY 109 | PATENTS TRADE-MARKS DESIGNS FOREIGN PATENTS “MUNN & CO. PATENT ATTORNEYS 683 WOOLWORTH BUILDING New York City 411 TOWER BUILDING Chicago, Il. Associated since 1846 with the Scientific American 522 SCIENTIFIC AMERICAN BLDG. Washington, D.C. 364 HOBART BUILDING San Francisco, Cal. 219 VAN NUYS BUILDING Los Angeles, Cal. batt Gee 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 DO FOR ( =—THIS FOR | DON’T LOSE YOUR RIGHTS } TO PATENT PROTECTION 4 ©. Before disclosing your invention to anyone Mm send for blank form ‘‘EVIDENCE OF CON- i CEPTION”’ to be signed and witnessed. A ig sample form together with printed instructions ff i will show youjust how to work up your evi- dence and establish thesame before filing ap- plication for patent. As registered patent at- f torneys we represent hundreds of inventors all iM over the United States and_Canadain thead- i# vancement of inventions. Ourschedule of fees A willbe found reasonable. The form ‘Evidence i of Conception,” sample, instructions relating 4 to obtaining of patents and schedule of fees seat epee request. Ask for them,—a post card A will do. PATENTS AND Registered Patent Attorneys in U. S. and Canada 274 Ouray Bldg. WASHINGTON, D. C. Originators of forms “Evidence of Conception.” our terms, methods, etc. Send of your invention for Inspec- tion and Instructions Free. Terms Reasonable. Best Ref- erences. RANDOLPH & CO. Dept.130, Washington, D.C. PROTECT NVENTORS your ‘ideas Send for our Guide Book, HOW TO GET A PATENT, and Evidence of Invention Blank, sent Free on request. Tells model or sketch and description ee ey © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17.

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POPULAR SCIENCE MONTHLY August, 1995 JA eer inet Shop Special No.7 You ought to have this handy Parks in your shop! A compact, complete machine designed just like a big production outfit at one-fifth the cost. Nothing extra to buy. Motor is in- cluded, operating from any light socket. Fits in a corner of your basement. Does any kind of cabinet and joinery work. Cir cular saw, jointer and bandsaw on per- manent all-steel frame. Add lathe, shaper and other attachments at small cost. You can make money with this Parks! Write for circular. The Parks Ball Bearing Machine Co. 1547 Knowlton St., Cincinnati, Ohio Canadian Factory: 200 Notre Dame East, Montreal, Canada ARK || h | | beaut thieedeues reefprpeplpertincecdel WORKING MACHINES BRINGS FAR AWAY OBJECTS CLOSER. Has five sections—cir- cumference 534”Made in Europe. Scientifi- & cally tested lenses adjusted by exe perts.Thousands # efpleased custo- £ mers. Order £m one today. 4 You are in 4 fora big : surprise, ‘ closes up to 12 in. Biggest telescope valueever offered. Only $1.85. For effi- oy Some to others costing $5.00. Brings far distant objects right before your eyes and also has a special solar eye - for looking at sun _ spots. veryone should have one. SOLD ON ABSO- ‘ LUTE MONEY-BACK GUARANTEE if not satisfactory. E. G. Patton, Kansas City, says: ‘‘Could count cattle twenty miles away.” L. B. Brown of Newark, N.J., says: “‘With it the last row at Boyle’s ‘Thirty Acres was as good as a ringside seat.’’ Free leatherette dust-proof carrying case With sling strap given with every telescope, Send No Money Simply send your order. When postman delivers telescope pay him $1.85 plus few cents postage. Order today. EXCELSIOR IMPORTING CO. ept. 114 90 Chambers St., N. Y. “Five-in-One”’ isa commination ric. Lor. ° tract S ae Hele. subtract, multiply and bination of whole mix: root ee Here Are the Rules in Our Great $10,000 Contest This Month’s ‘“‘What’s Wrong’’ Pictures on Pages 30 and 31 1 Every month for four months, beginning in ° the June issue, POPULAR SCIENCE MONTHLY is printing a set of pictures of John and Mary Newly- wed. Each of these pictures shows John or Mary doing some simple “job about the home’ in an incorrect way. And, in addition, there is a de- liberate error in the drawing of each picture. You are to tell us what two things are wrong in each picture and why they are wrong. 2 There are four complete monthly contests, ¢ each of eight pictures. The first was in the June issue, a second was in the July issue, the third is in this issue on pages 29, 30 and 31, and the last will appear in the September issue of this magazine. In addition, there will be a Grand Prize Contest covering all of the 32 pictures printed in the four months of the contest. 3 PoPULAR SCIENCE MONTHLY will award $10,- * 000 in 580 cash prizes for the best answers submitted in the contest. The cash prizes in each of the four monthly contests will be as follows: SA ee $500 - SRE ONEI a. c's -6 sinc u'-0ie 04.60 0-0 $100 Ee SS ere $50 Next 5 Prizes, $10 each... .....ee00- $50 Next GO Prizes, $5 cach... 2.00008 $300 CES eS ee $1000 MOnPMmOnths EObAl. . . . osc kisce scenes $4000 4 In addition, cash prizes in the Grand Contest ¢ will be paid as follows: oo Os asco eae $2500 oo See oe $1000 URINE one 6 lo: bun a lose: 6 wie alnic's $500 Next 5 Prizes, $50 each............. $250 Next 50 Prizes, $10 each... ... ...c000 $500 Next 250 Prizes, $5 each...........- $1250 Total Grand Prizes... .....ccccosves $6000 ne RINE ooo 5 sa tose wis soins v's 9 ee me $10,000 HOW TO COMPETE In connection with each picture these ques- 5. tions must be answered: ‘‘What job is being performed improperly in this picture and how should it be done correctly? And (2) What error has the artist made in drawing the picture and why is it wrong?” A list of errors—two for each picture—is in the custody of the judges and will be used as a basis for the selection of the prize-winners. Prizes in all of the contests will be awarded to those persons who answer best the questions for the largest number of the pictures. It is provided, however, that as between contestants having the same number of correct solutions the selection of winners will be based upon (1) accuracy; (2) clear- ness; and (3) skill of presentation. In cases of ties, a duplicate award will be given to each tying contestant. 6 Answers to each set of eight pictures must be * received not later than the thirtieth of the month following the date of publication of the Maga- zine in which the pictures appear. Thus, to insure consideration in this month’s contest, answers to the eight pictures in this issue, published July 10 must reach the office of POPULAR SCIENCE MONTHLY not later than August 30. Pictures received by this date will be entered automatically in the Grand Prize Contest also. Contestants, how- ever, may enter additional answers later for the Grand Prize Contest, or may enter for the Grand Prize Contest any time before September 30, with: out having entered a monthly contest. Con. testants also may hold the answers to all pictures until they have a complete set of 32 before sub. mitting the answers, it being stipulated, however, gg no such entry will be received after September WHEN SUBMITTING ANSWERS 7 Contestants may submit as many answers as * they wish to pictures in either the monthly con- tests or in the Grand Prize Contest, but each must be submitted in good faith. Answers may be sub- mitted on any kind of paper, but the writing must be legible and on one side of the paper only. Each picture will be numbered plainly and contestants must attach to their answers either the correspond- ing picture cut from the magazine or the number of the picture. The winning of one or more monthly prizes will not bar the winner from winning a Grand Prize, if he should submit answers. 8 All entries should be addressed to the Picture * Contest Editor, POPULAR SCIENCE MONTHLY, 250 Fourth Avenue, New York City. Name and | address of the entrant must be written plainly on eachentry. An entry with insufficient postage will not be received. The publishers cannot be respon- sible for delay, loss, or non-delivery of entries. No contribution entered in this contest will be returned. 9 Prize-winners in this month’s contest will be * announced in the January issue of POPULAR SctENCE MONTHLY, published December 10. Prize-winners in the September contest will be an- nounced in the February number. The names of the winners of Grand Prizes will be announced and the correct solutions published as soon as possible after the close of the final month’s contest. 10 You pay nothing. Just prove your knowledge * and observation. You need not purchase POPULAR SCIENCE MONTHLY to compete. You can borrow a copy from a friend or examine one at any of the offices of POPULAR SCIENCE MONTHLY or at public libraries free of charge. These contests are open to everybody, except employees of Pop- ULAR SCIENCE MONTHLY and the Popular Sci- ence Institute of Standards and their families. - The officials of the Popular Science Institute of Standards will act as judges and their decision will be final. Acceptance of these rules is an express condition of each entry. : See pages 30 and 31 of this issue for the third set of pictures in this remarkable contest. An addi- tional set of pictures, offering in itself a complete contest, will be published in the September issue. F YOU are unable to get the June and July issues of PopuLaAR SctENCE MontTuty contain- ing the first two sets of Contest pictures, copies of these issues are available for your free use at the public libraries or at the offices of this magazine. Or, if you prefer, you can obtain copies at 25 cents each from the Picture Contest Editor, Popular Science Monthly, 250 Fourth Ave:, New York City IS) This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17. August. Sea In throt sear Late Coul Ame thro’ the } preli gout alreé at t that rem:

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+ 1925 it be the aga- sure 8 to r 10, THLY the 10W- the rand vith- on- ures sub- ver, nber S as con- Lust sub- lust ach ants ynd- and

August. 1925 Searching Sahara Sands for _a Lost Continent (Continued from page 37) Inland the trail of exploration leads through hundreds of miles of desert in search of remains of vanished peoples. Late last spring an expedition under Count de Prorok, and including eight Americans, completed a 2000-mile swing through southern Tunisia, Algeria, and the Sahara in four motor-cars, making a preliminary survey of prehistoric sites. There are certain desert districts of southern Tunisia which, while they have already yielded traces of prehistoric man, at the same time have given evidence that their sands, abounding in fossilized remains, are a deposit of the sea. N ALL its explorations the expedition expects to collect thousands of speci- mens of flint instruments and other objects representing all periods of primitive man. In the meantime, recent geological study and exploration have aroused new scientific speculation as to the possibility of an altogether different location for the lost Atlantis. At least three develop- ments have contributed to this interest. One is a survey of the ocean floor, which reveals a vast bulk of land 1000 nautical miles wide, rising in mid-ocean and topped by mountain peaks, the tips of which pierce the surface to form the Azores. Another is the recent thrilling voyage of William Beebe, of the New York Zoo- logical Society, into the ocean wilderness of the Sargasso Sea, lying between Bermuda and the Virgin Isles. The story of his strange discoveries in this teeming mid-ocean jungle, as told inthe May issue of POPULAR SCIENCE MONTHLY, has added new interest to the legend that this vast expanse of 400,000 square miles was the vanishing place of the lost continent. A third development is the interesting theory, recently advanced, that the American continent slowly has been drift- ing westward. This theory, if substan- tiated, would give further weight to the location of Atlantis in mid-ocean; for, considered with the existence of such an island continent, it would help to explain how it happens that traces of early civilization so similar to that of Egypt have been found in Central and South America. If we imagine America 1000 miles nearer to Africa than it is today, with a vast island midway between as a stepping-stone, it is easy to picture the Atlantides drifting across the intervening waters in small boats. HE story of Atlantis, as preserved to us by Plato, pictures the vanished continent as encircled by mountains, with a fertile plain in the center. Scat- tered through the mountains were rich and populous towns, and ijn the center was a magnificent city, with palaces of

white, red, and blue stones. The soil of the plain produced rich crops. In the mountains were mines rich in ores. Science says that the existence of an Atlantis is geologically possible. Arche- ologists see in the legend a dramatic an- swer to the mysteries of civilized man’s origin.

POPULAR SCIENCE MONTHLY 111 BARBERING Now One of the Highest Paid Professions Be a White Collar Man Many Are Earning $90-*150 Every Week! Why Not YOU? What's the use of doing dirty, greasy, hard work, when others NOW make TWICE as much money in a manly pro- fession that is CLEAN, profitable and full of opportunities? Easy to Learn— Quick to Earn! That’s YOU BARBERING for ! And the best part of it all is this—scientific barbering, as modern M YO taught the way, makes a Master Barber in a short course of training, intensive at small expense! ou soon step out as your ewn Boss, if you wish, in your own Shop, which we will gladly help you equip. MOLER Graduates Are Always Busy! MOLER trained Men are always given the preference, for they alone possess the valuable, thorough MOLER training in the application of all the latest scientific Barbering methods, includ- ing the Electric hair cutter, the mechanical massage, and the latest vogues in ladies’ hair bobbing. MOLER also gives special training in ladies’ marcelling and an easy practical course in the treatment of skin diseases. MOLER SYSTEM OF COLLEGES New York, N. Y. Chicago, IIl. St. Louis, Mo. Kansas City, Mo. Cincinnati, Ohio. Cleveland, Ohio Detroit, Mich. Denver, Colo. Omaha, Nebr. Milwaukee, Wis. Atlanta, Ga. Memphis, Tenn. Dallas, Tex. Houston, Tex. San Antonio, Tex. New Orleans, La.

AN nS =e — aati NV pee h Earn While Learning! “‘Where there’s a Will there’s a Way” to earn BIG pay! Write to the nearest MOLER College, there is one near you, and learn how you can earn while you learn the barber trade. Ask for the new FREE MOLER Barbering Booklet C. Find out HOW MOLER helps you help ourself AFTER you graduate, as well as EFORE! Find out why MOLER Men are making DOUBLE the money others made last year, before Ladies’ Shingle Bobbing became so popular. You re NEXT in line for big pay—the MOLER way. Send Coupon TODAY! MOLER SYSTEM OF COLLEGES < sy = OE SS

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17. To make a tea wagon in your

Not Success and hinged at the top. The tray has a glass bottom. A Blueprint of this handsome tea wagon— — including full instruc- _ tions for making—can YW be secured by sending | 25c to POPULAR SCIENCE MONTHLY 250 Fourth Ave., New York

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112 POPULAR SCIENCE MONTHLY August, 1925’ Heats Home f 25°a Week! “I can run my Bulldog furnace steady for fourteen days in normal weather conditions on the actual cost of fifty cents.” So 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.” That’s what the Bulldog does with about the grade fuel you can think of! Here’s what it does with coal: “There is no heater to compare with the Bulldog. I burned 2% tons of coal last winter and heated 5 rooms and bath”— Walter Geary, Gloucester, Mass. | BULLDOG FF es Comes Completely Erected! Fits Any Height of Basement Goes Through Any Door You Install It Yourself! If you areeven 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 fits any height of basement, goes door, and you install i: yourserlf! No Money Down? The Bulldog is sent you for free inspection. en, Sati » you make only. small month! Payments, at our amazingly low git actory connections in both East and est. We ship from nearest point. Don’t cons buying any furnace until you find out about the Bulldog. Write at once for our special offer and our free catalog to- gether with the wonderful record of Bulldog ugh any success. Get ready for winter NOW! this coupon TOD. sshscees Babson Bros, es 19th & California Ave., Dept. C-136, Chicago Without obligating me in any way please send me your free catalog and special offer SESRESER Reese a gm onthe Bulldog Pipeless Furnace, = Print name and address plainly. : : URES CERO a a EEL ETS Ee J Jasseesee wissen ase mead Astonishing Things about Your Jewels (Continued from page 35) ; many times, but failed to find the hiding- place of the gems. At the end of a year and a half the family reached China and the emerald cutter brought his emeralds to America, where he sold them for $200,000. While he may never recover his properties in Russia, the future of his family was assured by that logful of jewels. Nine persons in 10, if asked to name the most valuable jewel, would say, “‘dia- mond.” The fact is, though, that in a table ranking gems in their order of value, carat for carat, the diamond has fourth place. Both emeralds and rubies are much more valuable, while the pearl is far above all others. The finest pearls come from the Orient, in the Persian Gulf. These have a depth and brilliant richness of color unap- proached by other varieties. Those with a rose-pink color are the most desir- able. There are black, brown, salmon, yellow, bright red, green, and purple pearls, as well as the milky-white variety. They are found in more than 100 different shades. HAT is one reason for the great cost of a perfectly matched pearl neck- lace. A dealer cannot go out and buy the pearls he wants. He has to collect them. Sometimes it takes years to do it, and he has to examine millions of dollars’ worth. While pearls are by far the most valued of gems, the most valuable single gem was a diamond. This was the Cul- linan diamond, the largest and finest white diamond ever discovered. It was found in South Africa in 1905, in Tom Cullinan’s mine, the Premier. This crystal, resem- bling a huge chunk of ice, proved to weigh 1% pounds. It was split into nine separate stones (the two largest weigh 516.5 carats and 309 3/16 carats respec- tively), and 96 brilliants. The stones can be seen today in the Tower of London among the British crown jewels. When I said that the prices of gems re- mained unchanged, I left out of considera- tion the effect of fashion which, by in- creasing demand, does cause a certain fluctuation from year to year. Fashion experts announce that “bracelets of emeralds are now very ‘chic’ for evening wear,” and soon there is a demand for such bracelets. ASHION has much to do also with the cutting of jewels. At present the fash- ion is to cut gems in the square or em- erald cut. This follows the general trend of fashion in clothing. Twenty-five years ago curves were fashionable. Women were round. Today they are oblong, and accordingly, prefer jewels cut to match. Cutting jewels is an exact science to- day. Until about 15 years ago jewel- cutting was left to the skill of the cutter. Now micrometers are used and every facet or side measured with minute exactitude to get the full benefit of refraction of light. Flaws in the rough stone help deter- mine, of course, the size and cut of the stones taken from it. About two-thirds | of a rough diamond is lost in the cutting. It is impossible to cut emeralds or Sap- | phires so that they have no flaws. - Al] have them. People often ask how to take care of their jewels. Will water hurt them? Will they keep in better condition jf worn than if put away? st DEARLS need far more care than any other gem, for they are an animal pro- duct that can be destroyed. An estate was being settled recently and a string of pearls was brought to me for appraisal. string 15 years before and was greatly sur- prised at its changed appearance. The pearls had worn barrel shaped. Each was long and thin. I made some in- quiries and found that the owner had the habit of wearing her pearls at night while sleeping. At night the largest percentage of acid is thrown off through skin pores and this had dissolved the pearls. These particular pearls were restored by peeling. A pearl is made of layers, like an onion, and these outer layers can be removed until the pearl has become round again. The peeling process is a most delicate task. It is done with the fingernails and a sharp knife. Only a few men in the world know how to do it. Face powder is bad for pearls. It clogs up the pores of the pearl’s skin, just as it does those of the human skin. Pearls should be wiped off with a soft cloth before putting them away, to remove powder and acid. The opal is another gem that requires great care. Made of silica and water, it is very fragile. It was probably because of this that superstitions of bad luck have been associated with it. Water, as a rule, will not - injure precious stones. Diamonds, rubies, and sapphires can pass through fire without injury. It is comparatively easy, though, to destroy both emeralds and dia- monds. They will shatter to bits if struck sharply. es OW can I tell if jewels are real?’”’ The more people hear of the clever- ness with which precious stones are imitated these days, the more they are asking this-question. Any one can test a pearl for himself. Many artificial pearls are hollow glass beads, witha sort of fishscale lining, a product of a small Mediterranean fish. These can be detected by rubbing the pearl gently over the edge of your lower teeth. If it is a glass bead it will feel per- fectly smooth. If it is a real pearl it will be slightly rough and grating. A Japanese cultured pearl cannot be detected in this way, for its outer struc- ture is exactly like that of a real pearl. It is a pearl formed by an oyster about a core of mother of pearl that has been slipped in the shell. One way of dis- tinguishing Japanese cultured pearls from real ones is examining them under a lucidoscope. By means of this machine one can look through the pearl and dis- tinguish the core. I had handled that same | pie ee mae we fr Pp is hor: exp at. pro trot pig qué clas blis wh firs abl bu ant bo bu 01 © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17.

Page 101

t, 1925 » 7 sap- All 2 of em? any pro- ntly -me ame sur- The ach in- the hile page ores 1 by like | 1 be und cate and the logs 1s it arls fore rder ires r, it use ave jure and out igh, dia- ; £ ver- are are elf. lass ing, ish. the wer er- will be uc- arl. it a een lis- om ine lis-

August, 1925 POPULAR SCIENCE MONTHLY

113

Beware of Sunburn (Continued from page 39) resence of pigment in the skin aids in transmission of light. That is, after you have acquired a coat of tan, the ultra- violet light can get through your skin, enter the blood, and be diffused through the body without being stopped on the way to produce a chemical burn. Recent tests indicate that there may be relief for non-tanning skins in a prepara- tion containing esculin, derived from

} HORNY LAYER GRANULAR LAYER MUCOUS LAYER TRUE SKIN

Diagram showing the construction of the skin. The protective pigment that produces tan and freckles is manufactured in cells of the deep- est of three layers forming the epidermis, or outer skin, that covers the true skin. The pigment looks like specks of brown paint and is represented by the small dots in the diagram horse chestnuts. This is put on before exposure to the sun. When you fish or lie in the sun for hours at a time, exposing skin that has been protected all winter, you are inviting trouble. The skin cannot manufacture pigment quickly enough or in large enough quantity to protect you from burns. Burns may be considered in three classes—first degree, when the skin is simply inflamed; second degree, when blisters are formed; and third degree; when charring takes place. A burn of the first degree, covering the entire body, prob- ably would result in death. A blistering burn on half the body would be as severe, and a charring burn on a third of the body, equally so. That is, a superficial burn is as serious as one that blisters, if covering twice the area. You probably have noticed that you have suffered your worst burns while you were on water in a boat. That is because water reflects ultra-violet light and this reaches your fate and eyes, even if they are protected from direct rays of the sun by a hat. Some of the light penetrates water, so that you may_be sunburned even while swimming. One of the best and simplest treatments for shock from sunburn, is to get into a tub of lukewarm water into which a pound of bicarbonate of soda has been dissolved. A physician always should be called, since heart stimulants may be re- quired to prevent collapse. Any sort of fat helps to sooth sunburn. Either lard or butter can be used in an emergency.

BEND ality] ATHES 19T Prices Quick Change Gear Lathes 9"x3’ - - $241.00 11"x4’ - - 288.00 13" x6’ - - 366.00 16" x 8’ - - 498.00. Easy payments if desired. Write for Catalog No. 84

Sitti Challenge the World in Lathe Value Quantity Production reduces our costs. We pass the saving on to you. SOUTH BEND LATHE WORKS isise on 816 E. Madison St., South Bend, Ind. Lathe, Price $431.00

ick Change Gear

Clarity and Tone Range With Kellogg Transformers | The reproductions of the highest tones as well as those of the lower extreme of the scale, with faith- ful, pure quality, is essentially. the spirit of Kellogg Transformer design. The Kellogg radio frequency transformer is of the low loss type, having many important features. It will operate at all wavelengths with .00035 to .0005 variable condensers. For best results, use the Kellogg .0005 low loss variable condenser. Kellogg R.F. Transformers at all dealers $2.35. Kellogg audio frequency transformers give greater volume with cleare: reproduction, due to the high quality materials and expert work- manship, used in the Kellogg process of manu- facture. Kellogg audio frequency transformers are made in both shielded and unshielded types ranging in price from $3.50 to $4.50. Kellogg transformers can be obtained at all radio dealers. iS} KELLOGG SWITCHBOARD &. SUPPLY CO. 1066 W. Adams St., Chicago, Ill. The Vest Pocket Bookkeeper A simple and concise method of practical bookkeeping, with short cuts in figures and complete instructions for the correct keeping of books of accounts. A working model adapted to the novice and business man is included. 160 pp. Price $1.00, postpaid. POPULAR SCIENCE MONTHLY 250 Fourth Avenue, New York, N. Y. TIRES WITH 500 NAIL HOLES LEAK NO AIR A new puncture-proof inner tube has been in- vented by a Mr. Y. Milburn of Chicago. In actual test it was punctured 500 times without the loss of air. This wonderful new tube increases mileage from 10,000 to 12,000 miles and eliminates changing tires. It costs no more than the ordinary tube. Mr. K. Y. Milburn, 331 West 47th St., Chicago wants them introduced everywhere and is making a special offer to agents. Write him to- day—Adv.

tt ‘ : », Easy to Play Easy. to Pay Bei True-Tone Saxophone Easiest of all instruments to lay and one of the most autiful. Three first lessons sent free give you a quick easy start —in a few weeks you can be playing popular tunes, No teacher neces- .\ sary. You can take your @ placeinaband ororchestra Ty, in ninety days, if you so desire. ‘ae? Most popular instrument for dance <5 orchestras, home entertainments, / church, lodge and school. A Saxo- ' phone player is always popular socially and has many opportunities to earn money. Six Days’ Trial and easy payments arranged, (105) Showsall Free Saxophone Book frer52 models and gives first lesson chart; also pictures of famous rofessionals and orchestras. Just send your name for a copy. ention anyother instrument in which you may be interested. BUESCHER BAND INSTRUMENT CO, Everything in Band and Orchestra Instruments 70. « ELKHART, INDIANA

BENNIE KRUEGER Director Bennie Krueger and His Orchestra. Bruns- wick Records. 35 BUESCHER BLOCK - “DON'T SHOUT” “T hear you. I can hear now as wellas anybody. ‘HOW ?’ With THE MORLEY PHONE. I've a pair in my ears now, but they are invisible. I would not know I had them in, myself, only Mm that I hear all right.” The Morley Phone for the DEAF is to the ears what glasses are to the eyes. Invisible, comfortable, weight- less and harmless. Anyone can adjust it. Over one hundred thou- sand sold. Write for booklet and testimonials. THE MORLEY CO., Dept. 797, 10S. 18th Street, Philadeiphig toyou Free for 30 days trial on approval. Your ,aame choice of 44 Styles, colors and sizes of {BM the famous Ranger Bicycles. Express pre- (aly paid. Bicycles $21.50 and u 4 5 a Mon if desired. Many boveand girls easily make the sycie earn the smalimonthly payments. wheels, lamps and equipment at i i ires half usual prices. Writutor remem: ST: able tactory prices and marvelous offers. 7 CYCLE COMPANY Wete ve tw today for WY DEPT. A-250 CHICAGO free catalogN\

Boice-Crane

quicker and easier. with or without motor. Prices. Ww. B. & J. E. Boice, It’s Easy to Build Things! Perform every woodworking operation with greater speed, accuracy and economy on Bench Band Do ripping, mitering, grooving, rabbeting, sand- ing, grinding, and band saw operations better, Driven by any \% to h. p. motor; portable; attached to any light socket. Sold Unsurpassed values and Write today for descriptive catalog of Bench Saws, Drills, Jointers, Band Saws and the Boice E-Z-Pay Plan. Dent. P. S. 8-A, C World's Largest Makers of Small Bench Machines.

‘Saws Toledo, Ohio.

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the cnproval of the INSTITUTE OF STANDARDS. See page 17.

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114 POPULAR SCIENCE MONTHLY

August, 1925

“I’m going to raise his salary”’ “T’ve had my eye on him for some time and I know he can handle big- ger work. “He studies those I.C.S. text- books every chance he gets, and I want to tell you it has made him a valuable man for this business. “I’m going to raisé his salary and give him that new job we were talk- ing about. I wish we had more men like him.” ee How do you stand when_your employer checks up his men for promotion? Does he pass you by as just a routine worker, or does he think of you as a@ man who is ambitious to get ahead? Won’t you be far more likely to get the promotion if he knows you are studying at home and are really preparing yourself to handle bigger work? Think it over. Then act. It takes only a moment to mark and mail the coupon and find what the International Correspondence Schools can do for you, yet that one simple little step may be the means of changing your whole life, ‘Do it now.” ee Ee ee a INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7663-D, Scranton, Penna. Without cost or obligation on my t, please tell me bow I can for the position or in the subject before which I Bh aye Ae an X: BUSINESS TRAINING COURSES Salesmanship Advertising

and Banking Law Business (including C.P.A,) (Lj Civil Serv Accounting French Llustratin TECHNICAL AND INDUSTRIAL COURSES Electrical Engineering Architect Architects’ Blue Prints Contractor and Builder Architectural Draftsman Concrete Builder Structural Engineer

gine Operating Chemistry (J Pharmacy Engineer Automobile Work ing and Mapping Airplane Engines Metallurgy [mt] Agriculture and Poultry D Badio Mathematics

City. State.

Persons residing in Canada should send this “coupon ‘to ‘the Anternational Correspond Schools Canadian, Limited, Montreal, Oanada

Inventor's Universal Educator contains 900 mechanical movements; 40 per- petual motions. Tells how to obtain and sell Patents. Suggests new ideas. Explains how toselect your attorney and avoid patent sharks, Special price (for a limited time) $1.00 postpaid. Albert E. Dieterich, 681-A Ouray Building, Washington, D. C 7,4: DUPLICOPY = EASY TO OPERATE NEAT AND FAST AGENTs wanTED

Reproduces cartoons, sketches, typewritten, handwritten mat- yp a ES ousan one inal, -00; size $11.00; Letter size $1 00. Write today, i coadice et work and five day free trial offer. DUPLICOPY Mig. Co., 626 Jones St., San Francisco,Cal,

Country Schoolmaster Stirs the World | (Continued from page 27) and thus environment was a large factor in producing new types of creatures. Scientists, who became convinced of the truth of this theory, held, too, that man took part in this general scheme. Darwin himself said that scientific facts | indicate that man’s nearest kin was the Old World monkey. “But,”’ added Darwin, ‘‘we must not fall into the error of supposing that the earthly progenitor of this whole simian stock, including man, closely resembles existing apes or monkeys. What evolu- tion shows is that the five great vertebrate classes—the mammals, birds, reptiles, amphibians, and fishes—are descended from one prototype—probably a fish.” This theory has. been borne out by geological and fossil discoveries made since Darwin’s day by scientists in many parts of the world. Fossil remains found in the rocks indicate, according to the conclusions of science, that in one period of the earth’s history its animal inhabi- tants emerged from the sea and became land dwellers. It is to this theory that anti-evolu-

tionists object. They hold that the earth and its plants and its animals were created as described in Genesis, the firgt book in the Bible; that to accept the theory of Darwin and his followers is tg strike at the foundations of religion,- - It was to prevent the further promulga- tion of this theory that the legislatures of Tennessee and Oklahoma enacted statutes making it unlawful to teach the theory of evolution in the public schools of those states; that in 15 of the remaining 4g |. states either anti-evolution legislation has been instituted or other means taken to prevent the teaching of the theory in the public schools. Evolutionists, however, insist that to hold the theory offers no challenge to religion or to belief in a creator. The evolutionist, they admit, cannot accept the story of the ark, of the creation of the world in six days or 24 hours, and of the separate creation of man and the other animals. He can, though, they say, believe fully in a creator who made a world in six geological eras; a place in which evolution began and continued.

Some Inventions and Discoveries (Continued from page 49) according to Dr. Carl Murchison, pro- fessor of psychology in Clark University, after testing the mentality of several thousand criminals and comparing the results with those of tests on army men.

New Cars and New Fuels RONT-DRIVE automobiles will be the next improvement in motor-cars, in the opinion of Capt. Eddie Rickenbacker, manufacturer and former race driver. Cars of this type now being used for racing, show great speed. With power going into the front wheels, practically all skidding is said to be eliminated. These new cars may be run on ether, or with a fuel derived from molasses, it is reported. E.C. Freeman, chemical engi- neer, discussing these possibilities before the American Chemical Society recently, declared that the use of ether would do away with dirty cylinders, since ether burns with no solid product of* combus- tion. Molasses fuel, he added, would give great power combined with smooth- ness of operation and ease in starting. Another fuel possibility is a new syn- thetic alcohol known as “methanol,” imported from Germany. It is a wood alcohol produced from coal and water, and is a result of researches carried on in Germany during the war, to find a sub- stitute motor fuel. The Moon Snatched Away? HE moon was stolen from the earth. A layer of the earth’s crust about 41 miles thick and covering two-thirds of the globe’s total area was pulled off by the sun’s attraction. It rolled up into a ball and became our beautiful satellite. This new and interesting theory was announced recently by Dr. R. H. Rastall, lecturer in

economic geology at Cambridge Univer. sity. What remained of the earth’s crust after this had happened became the continents, According to this theory, if we had no moon we might have no oceans, for these occupy the space once covered by crust. This explanation fits in well with the ideas of a German geologist, Prof. Alfred Wegener, who believes that the American continent originally was united with Europe and Africa, and floated away to where it is now. This might have hap- pened when the moon was torn away.

An Unnamed New Gas JF 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. The Next Total Eclipse OCTOR J. A. MILLER, director of the observatory at Swarthmore Col- lege, whose interesting story of this year’s solar eclipse appeared in POPULAR SCIENCE MONTHLY recently, is getting ready to journey halfway around the world to the west coast of Sumatra, to observe the next total solar eclipse. It is scheduled to appear on January fourteenth of next year. The narrow path of totality passes over East Africa, Sumatra, and _ the Philippines.

RASPBERRIES as big as_ blackberries that grow in the Andes Mountains are suited to cultivation in California, recent experiments have shown.

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

AUTC Peg ths <a | &

Page 103

f the f the other say, de a ce in d. iver. after ents, d no shese rust. . the lfred rican with y to hap- un- ; the reful rof, leck who ‘ien- | gas r of Col- ar’s NCE ’ to the the led ext the August, 1925 [Made 212 In Five Hours —Writes Peter Werner, III. Sell Madison “Better - Made” Shirts for Large Manufacturer Direct to wearer. No capital or ; experience needed.. Many earn *® $100.00 weekly and bonus. Write for Free Samples ae. SHIRT M’FRS, 505 Broadway, New York Agents gaa Bap raty — i,t 000 ch aeatrrenD on appro Make bee. eno pet or part tim e. Nocapitalor MELLINGER TIRE “a RUBBER co. §f J ily Dept. 310, Philadelphia, Pa.,or Kansas ity “AGENTS: *100 aWeek Men and women wanted at once! In- aed Perfection Pie Filling. Lightning : oailes. Noeggs, no milk, no butter need- . Just add water and bake. Delicious -.' rhan ty by new plan that makes amaz- $50 to $100 a Week 50. Zanol Products, all household favor- a Toilet preparations, pure food prod ucts, flavors, soaps, peunes. eS \ laundry necessities, etc. P rices. Supreme quality. Com: ete outfit Ree. Weeupply automohile. rite quick. Make $100.00 a week and up, sellin our fine made-to- Beery = all-woo livery and collections. 6x9 swatch sam- ples—over 100 styles all one price—furnished ¢ FREE. Part or full time men write at once. W.Z. Gibson, Inc.,161 W.Harrison St., Dept. H.521Chicago ZIP-ZIP LET’S GO BOYS Y No matter where you go, camping, hunting, fishing boating, to the country, the seashore or the moun- tains, p will need a Zip-Zip shooter. Thousands of boys are meade 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. Dept. 22, Columbia, S. C. DEPENDABILITY AGENTS Y 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. Y. Clear’ Skin - pd Skin Can Be Quickly ~~ of Pimples, Blackheads, Acne mregtions on the face or body, Barbers Tteh, Pores and Oily or Shing Skin. Write today for my FREE OKLET, + “A CLEAR-TONE Bare, pelle how £ cured myself after being afflicted fs years. E.S.GIVENS, 153 Chemical Bidg., Kansas City,Mo. POPULAR SCIENCE MONTHLY Insects in Your Back Yard (Continued from page 45)} daily to forage for food. A few days later they move to a large fork of the tree and construct an ugly web. The family sticks together, resting in the tent during storms and the heat of the day, going out when it is-cool for food. They are very easily killed - when they are gathered in their tents. When the larvae are fully grown they become more venturesome and strike out, hunting for protected places in which to spin tough, oval, white cocoons. These, as well as the egg masses, can be picked off of trees easily and destroyed. By contrast there is the peach-borer, which is said to do yearly damage amount- ing to $6,000,000. The adult is a moth with skeletonized wings that look as if they were covered with varnish. The caterpillars bore in trunks and roots of peach-trees and also infect the wild cherry and willow. You can tell that trees are being both- ered by this pest by large masses of gum exuded from the trunk where the cater- pillars are working, usually near the ground. When the caterpillar has reached its full growth, it leaves its burrow and makes a cocoon of pieces of bark and silk on the tree trunk or ground. These co- coons can be removed and destroyed, but they are exceedingly well hidden and the damage already is done. Two hundred and forty-eight varieties of butterflies and moths were found in Doctor Lutz’s yard. These vary in size from those as big as a small fly to specimens of the gorgeous tiger swallow- tail with its striking golden wings striped in black. On a summer evening when you hear the chorus in the garden, you are most likely to appreciate the size of the vast army of insects there. The grasshoppers, for example, announce themselves by a peculiar rasping sound made by rubbing their hind legs against their front legs or by rattling their hind wings while flying. These extraordinary sounds, we are told, are love songs and their beauty is ap- preciated only by the female grasshopper, who is equipped with special sort of ears, one on each side of her abdomen. Insects, just as human beings, often are misjudged from their appearance. The dragon-fly, for example, looks vicious, so we give it the innocuous title of “‘devil’s darning-needle”’ or “‘horse-stinger.” Asa matter of fact, it stings neither horse nor man and is dangerous only to other in- sects. It catches these by swooping upon a victim and scooping it up in its legs, curved to form a basket. The hundreds of insects in your garden all are interesting if you know how they live, what they eat, and how they grow. On your window-screen there are perhaps 20 flies of different sizes. There are 20 different kinds of flies, for a little fly does not become a big fly. Insects do not grow after they have wings. Each of these 20 species has a story. With the rich field of entomology just outside your kitchen door, in your own back yard, you have only yourself to blame for neglecting a fascinating study. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. yy err SN ne GS ULTRADXRE MURDOCK aAZarRKk CG, Micnisas Deresnadyne MALONE LEMON MASTER RADIO ADLER” ROYAL HORD AMPLIFYING 1 cscmnaeal Standard on the majority of quality sets “Highly Satisfactory” reports Deresnadyne “Thr results obtained with Thordarson Transformers in the Deresnadyne Re- ceivers manufactured by us have been highly satisfactory,’’ advises Mr. E. Andrews, of the Andrews Radio Company, Chicago. “The Deresnadyne has a country-wide rep- utation for the beauti- ful quality of its repro- duction and its ass dom from undesired noises. The signal from the detector is faithfully reproduced by your transformers with excellent amplification. Sub-Panel Mounting “We have been very Type Thordarsons favorably impressed by Now on Sale. a . 7. ‘ product an the fact oscmuliig? ie ceases that we have had a sur- of leads and the conceal- prisingly small amount pong ey gg in. fac- of transformer trouble.” pe $8 ar i nt Follow the lead of the standard type ordar- sons. If dealer cannot leaders. supply, order from us. Build or re- place with Thordarsons, Types and Prices Thordarson ‘Super’ Audio Frequency Trans- formers are to be had in three ratios: 2-1, $5; 344-1, $4; 6-1, $4.50. Thordarson Power Amplifying Transformers are $13 the pair. Thordarson Inter- stage Power Amplifying Transformer, $8. All Thordarson products are unconditionally guaran- teed. Dealers everywhere. Write for latest hook- up bulletins—free. THORDARSON ELECTRIC MFG. CO. Transformer Specialists since 1895 World’s Oldest and Largest Exclusive Trans- former Makers. CHICAGO, U.S.A. See page 17.

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t Win the Contest With a Hohner! In the principal parks and playgrounds of the leading cities contests are now being held to determine the champion harmon- ica players. In each community some boy or girl will be the winner and enjoy the honors, rewards and opportunities that come with victory. (Get into the fun today and win the contest with a Hohner. Hohner Harmonicas have always been the leading favorites of leading players. They are true in tone, accurate in pitch and perfect in work- manship. Anyone can learn to play a Hohner with the aid of the Free Instruction Book. Ask your dealer for one today; if be is out of copies, write M. Hohner Inc., Depts 182 New York City. Leading dealers everywhere sell fi Hohner Harmonicas—50c up. POPULAR SCIENCE MONTHLY (12-Cell — 24-Volt / ‘Storage‘B’ Battery Positively given free with each pure! oe, a WORLD “A” ) ittery. send ad with your order, WORLD Batteries are famous for their guaranteed quality ed ears Rubber Ca. inst ecid and leak- per cent and geta 2-Year Guarantee Bond in Wri WORLD Bst- | Approved and Listed “‘tell their friends.’’ That’s A; OE of performance. Send your order in today Standard Rubber Case Radio Batteries as Standa iperes 6-Volt, 100-Am -25 | by Leading 6-Volt, 120-Amperes. +. > > ° 13.25 } a, oy = 14.00 | Authorties Solid Rubber Auto Batteries | including Radio 6-Volt, 11-Plate . . 2... -s $11.25 | News bora- 6-Volt, 13-Plate 2... t 13.25 | tories, Popular 12-Volt, 7-Plate Science Inst EZR 16.00 | Sc qast No Money 225) Sisiea‘end | ards, Popular we wilt chic day order is ved, by Ex- a press C. O. D., subject to your examinati prem arel, EREE B'S Batters iaeadek, Offer: ‘ in fal with order. Buy Sow and goto guar-¥ in oe, Home. Here Are Correct Answers to Questions on Page 55 1. Because the paper keeps the ice from melting and this interferes with the cool- ing effect of the ice. When ice melts it takes up and absorbs a certain amount of heat in the mere act of melting. This is what you use ice for; to take up heat. 2. If the temperature of the body itself gets above 107 degrees, even for a short time, death is nearly certain. The body can withstand an outside temperature much higher than this. 3. Lack of air does not cause actual death until the tissues of the body have been without oxygen for some time and have suffered serious chemical changes as a result. If you restore breathing arti- ficially before these. changes happen, the tissues will recover. 4. We are not sure. Bats may have some extra sense we do not know of. But scientists believe that bats possess ex- tremely sensitive ears and can hear echoes reflected from walls, trees, etc. 5. Because it stays the same height in the sky. Anything on earth, like the top of a church steeple, seems to sink lower toward the horizon as you go away from it. Of course the moon is much too far away to do this. 6. The fundamental cause is that the water in the tropics gets hot and the water in the polar regions gets cold. This starts a circulation of the water. 7. The color of clothes is usually due to dyes. Dyes are very complex chemical compounds. Many of them are affected by light, changed into other chemicals. 8. The sign contains a great number of electric lamps, each one connected sep- arately with a switch. These switches are mounted on a revolving cylinder like a barrel. This cylinder is turned by a motor. As it revolves the switches open and close. This makes the individual lamps on the sign light up and go out in succession to form designs. 9. Because the gas-pipes are not always connected electrically with the earth. 10. In some kinds of plants this is caused by fall of temperature at night; in others it is caused by lack of light. These latter flowers will close up any time if carried into a dark room. . 11. One of the functions of the liver is to store up sugar and hold it as food material which can be drawn out and used when- ever there is an emergency. When the adrenal glands are preparing your body for a fight, one of the things they do is to affect the liver so that some of its stored- up sugar is poured out instantly into the blood. This sugar then becomes avail- able as a quick food supply for the mus- cles in case they have to work very hard fighting or running. 12. We all have an unconscious ten- dency to imitate whatever we see other people do. If everybody around us is in a panic, or laughing, or running to a fire, it makes us want to do the same thing. Yawning when other people do so is simply one instance of this tendency to imitate. It is such a common instance because yawning is an easy thing to do and one which we are much more likely to do than we are to get in a panic or run to fires. | Squab Book FRE Auguss, 1925". Squabs selling at highest prices ever own Greatest market for 20 years. Moke ai breeding them. Raised in one month, ship everywhere our famous breeding stock and pteprnes. Established 24 years. rite now for g illustrated How to Make Money Breeding ¢ 200% PLYMOUTH ROCK soUAR we »616 H St., Melrose tithen ae TORCYCLES ie é nN Wii Dien Sidecars. neve nts i ‘ Wanted.Write for ¥: i Wo AMERICAN MOTOR CYC e Y 2047 W. Chicago Ave., Dept. ea Chiccco AGENTS 500% PROFIT GENUINE GOLD LEAF LETTERS Guaranteed to never tarnish. Anyone can put them on stores and office windows, Enormous demand, large profits, Paul Clark says: smallest day $28.70. R.L. Reel made $920 in two months. Write today for free sample and liberal offer to general agents, METALLIC LETTER CO., 433A N. Clark Street, Chicago, LIGHTNING— Wonderful New Electrolyte charges discharged batteries instantly. Eliminates old sulphuric acid method entirely. Dissolves sulphation. World has waited half a century for thisinvention. One gallon, retails $10.00, free to agents. LIGHTNING BATTERY CO., ST. PAUL, MINN. Leatherette Carrying Case Free with Big 8 e. 5 sections. ul lenses. eople and objects miles away as if they were close. See moon and stars as never before. Useful and entertaining. “Could tell color of ae 4 miles . H ( on freight cars mile away.: AC ABR YE ree “LIGHTING FIXTURES” Ready to hang. Direct from the manufacturer. Completely wired including glassware. ws ¢ Send for New Catalogue No. 27 - (Just reduced prices) Special proposition to Dealers ‘Ea ERIE FIXTURE SUPPLY CO. Desk A, Erie, Pa. $75. to $150. Weekly jar INSTANT WELD Welds RubberIn- case stantly. Better, quicker, and easier Wo-ckM ei) than vulcanizing. ONCE ON—AL- Necuieetm WAYSON. No Heat or Cement re- aes quired. Repeat orders sure. Big prof- m™ its. Appoint sub agents. Write today. ; TOURISTS’ PRIDE MFG. CO Desk No, 30H Minneapolis, Minn, CALTRA-LOWLOSS Ca ; &:7 PHENIX RADIO CORP.,'116-F-East 25 St... N-Y.C. $822 a Day ater Write quick for new proposition. We offer $8.00 a day and a new Chevrolet Coach for demonstrat- ing and taking orders for Comer S All-Weather Topcoats and Raincoats. Spare time. No ex- (3m perience required. Sample out-\@ fit free. Write now. “£$5.00 Comer Mfg. Co., Dept. 0-412 Dayton, O. riS} This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17. August, | — Fa lis

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mi i <3] E ail F abi

itd

ls Oo.

August, 1925

————— Facts about Tuning Coils (Continued from page 70) Of course, other conditions might enter into any consideration of the effect of moisture, as far as the average radio set is concerned. In the first place, these test coils were absolutely clean—not covered with a layer of dust and grime that would help to keep the water in contact with the wire and even absorb it from the air. It seems fair to assume, however, that any radio set kept reasonably clean and in a house where the dampness is not so great as to injure the health of the inhabitants, should give good results so far as any effect of moisture is concerned. In connection with the test of the com- parative efficiency of silk, cotton, and enameled wire it might be well to point out that the material of the tubing on which the coil is wound probably is of great importance. At least, it is obvious that if the tube composition is of a type that tends to increase the high-frequency resistance, then the thinnest insulation would naturally give the greatest re- sistance, because it would allow the wire to come that much closer to the coil form. The Popular Science Institute of Stan- dards Radio Laboratory is now planning a series of tests on coil forms made from different kinds of material and the results of these tests will appear in a future issue of POPULAR SCIENCE MONTHLY.

Recent Publications Concerning the Nature of Things, by Sir William Bragg. A thorough explana- tion, making clear to the layman, through simple experiments and homely illustra- tions, the structure of atoms, gases, liquids, and crystals. Illustrated. Har- per & Brothers. Roper’s Questions and Answers for Steam Engineers and Electricians. What a capable engineer should know. A hand- book enlarged and brought up to date. David McKay Co. Aspects of Science, by J. W. N. Sullivan. Essays explaining the fascination of science for the layman as well as the specialist. Alfred A. Knopf. Man and His Affairs from an Engineer- ing Point of View, by Walter N. Polakov, M.E. Williams & Wilkins Company. Workshop Gauges and Measuring Ap- pliances, by L. Burn. Isaac Pitman & Sons. The Painting Trade Handbook, by A. Ashmun Kelly. A full synopsis of practi- cal information, most useful to house- painters. Illustrated. David McKay Co. The Personal Equation, by Louis Ber- man, M.D. Why one man is a genius and the next a nonentity. The influence of glands in determining individual char- acter. Illustrated. The Century Co. The Wonders of Electricity, by A. T. McDougall, B.A., B.Sc. Isaac Pitman & Sons. Henley’s Workable Radio Receivers, by John E. Anderson and Elmer H. Lewis. Complete instructions for the construc- tion of many of the standard forms of radio receivers. Illustrated. Henley Pub- lishing Co. Pioneer Inventions and Pioneer Patents, by Frank Keiper, M.E. Pioneer Pub- lishing Co., Rochester, N. Y.

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99 And Almost His Life— Before Learned

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

A e E N T Ss — mee ‘Dulendid prods, for special offer.

See page 17.

Page 106

WuRLIIZER Couldn’t Play a Note— nova] 000 a week “Bill Carola”’ Landa s J J e Read Bill Carola’s story in his own words— **When I sent for your catalog, I wanted a Tenor Banjo, but I hesitated a long time as I didn’t know a note of music. I finally decided to try it a week, as you offered, and at the end of that time I found I could pick a few notes. Then I started the correspondence course you furnished, and in seven months, even before the final payments on the Banjo were due, I had taken my place in a professional orchestra. Now I am making $100 a week, three times what I made as aclerk. Two of my friends made money with their instru- ments after five months practice, one a drummer and the other a saxophonist, and neither could play a note when he started. I wish everybody knew how easy it is—anyone who can whistle a tune can learn to play a musical instrument.” Bill Carola New Offer Learning to Play Made Easy We now furnish FRE with every in- strumenta Free Scholarship Certificate. This scholarship entitles you to free tuition in one of the foremost correspondence schools of music in the country. Whether you want to learn to play for profit or only for pleasure, this Free Scholar- ship will make it surprisingly \ easy for you. Free Trial Easy Payments You may have any Wurlitzer in- strument for a week’s free trial in yourown home, No obligation to buy. Payments are arranged in monthly sums,a fewcents a day will pay for your instrument. |}, Worlitzer instruments arethere- | \) sult of 200 year’s experience in musical instrument building. Famous for artistic quality, rich tone value and fine workmanship. Used {in the finest bands and orchestras throughout the world. Free Book Illustrates and describes every known musical instrument—over icles. offers on complete outfits. Special prices direct toyou, We also give you Free Tri our plan and special Free Scholar- ship Otter. ‘No obligation. Send Coupon Tod Rudolph Wurlitzer Co., Dept, C-178 IE th St, Cimcignati 329 So. W: Ave., Chicago 120 W. 42nd St. New York 250 Stockton St., San Francisco kk on Musical Inst: ts. iis ‘your Bree Tris Seay Payment plan and. Free Scholarship offer. No obligation. Name. Address City State. Instrument ......------..-- » (State instrument in which you areinterested) POPULAR. SCIENCE MONTHLY August, 19% of rheostat G. From the other terminal of rheostat G run a wire around under- neath variable condenser D to the remain- ing filament terminal of socket J and from there to the remaining terminal of socket K connecting, also, with binding post No. 5. After this you should connect the lower terminal of coil B with the stationary plates of variable condenser D, and con- nect the other terminal of coil B with the rotary plates of condenser D. Continue this wire to connect with the wire that — 134" 2%e——_4 3 mE ee] = o-- s vz -o-+ se os 4 7 a + bee ~@—L) aan Lye 3" —— 3" Ye" be 7 a Fig. 8—The panel diagram, with the exact measurements for laying out and drilling holes joins the positive filament terminals of sockets J and K. Now run a wire from the other end of the stationary plates of condenser D to one terminal of grid condenser E and connect the other terminal of condenser E with the grid terminal of socket J. EXT, connect one terminal of coil C with the wire from rheostat G that goes to the filament terminals of the sockets. Connect the other terminal of coil C with condenser F and run a wire from the other terminal of condenser F down to the plate terminal of socket J, with a branch over to the P terminal of audio transformer H. Now connect the grid terminal of transformer H with the grid terminal of socket K. After this you can run a wire from the plus-B terminal of transformer H down to binding post No. 6 and continue it on to binding post No. 7. Then connect the plate terminal of socket K with binding post No. 8. Connect one end of coil A with the wire from the filament terminal of socket K, which also is connected with the rotary plates of the condenser. Complete the wiring by eonnecting the other end of coil A with binding post No. 1. To put the receiver into operation, connect the antenna wire with binding post No. 1 and the ground wire with binding post No. 2. The A battery is connected with binding posts Nos. 3 and 4; the positive terminal with No. 4. The B battery is connected with binding posts Nos. 5 and 6, the positive with No. 6, and the head-phone cord tips should be clamped under binding posts Nos. 7 and 8. Ifthe cord tips are marked “ positive”’ and “‘negative’’ by means of a thread in one cord, be sure that this tip is clamped under No. 7. Turn the rheostat all the way off and place the tubes in sockets J and K and the grid leak L in the clips on condenser E. Now turn on the rheostat G until the tubes A Compact Two-Tube Receiving Se (Continued from page 67) ————_ are. burning faintly and then tune the with the dial on condenser D and the knob on the shaft that turns coil C. Be guy that you keep the knob that controls the angle of coil C turned back to the Point where the receiver does not howl. "THE efficiency of any receiver depend; on the antenna you use and if you are a long way from any broadcasting station, the higher and longer the antenna the better the results you will get. ie building the case for your complete port. able outfit, it will be well to figure on a coil of flexible wire about 100 feet long ang if you find that there is no location for ay antenna as long as this in your camp, then make the antenna as long as possible with the unused portion of the coil rolled up tightly at the far end of the antenna, A good ground connection is just ag important as a good antenna. A piece of wire thrown into a near-by brook or lake is the best obtainable. If you are not near water, then a very fair ground can be obtained by laying 100 feet of wire on the ground underneath the antenna, or you can drive an iron rod into the ground, The frame of your auto also will give fair results as a ground connection and if you are using the storage battery in your car to light the tubes in this portable set, no special ground connection with the frame of the auto will be necessary. Fig. 9—View from the right end showing clearly the hook-up of the tuning condenser ‘‘Bottling’’ Wireless Messages IRELESS messages now can he ““bottled”’ and preserved indefinitely, it is claimed, as a result of a new German; invention. A long steel wire wound ona spool serves as a record. By means of a motor this wire is passed through a power- ful magnetic field, which varies in inten- sity according to the transmitted impulses. In traversing this field, the wire is mag- netized and the various sounds literally are “frozen” upon it. The magnetized wire can be reversed and run past a soft iron core which, in turn, is magnetized, creating a field of magnetism itself. The wire duplicates the fluctuations impressed upon it and gives back through telephone receivers the sounds originally made. New Finish for Autos UTOMOBILES now can be refinished quickly by spraying on, with com- pressed air, a very durable finish made of much the same material as that used for the backs of imitation ivory toilet articles. ® This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17. august, 1 a8 poss are ba plates patter} practic battery The equipn speake Do not just tE spacin speake from ¢ and if the wl Like ratus, ligent troubl some to she Re H cu gure 4 howe’ insula chemi to ele 000,0 of pl inch game inch s 000 n dista1 ’ TS pel pins : of th great the T 20,00 ANTS agric slowl prod ants, reinf REM. histo unde form velt | whic PAR’ chick for 1 ment

Page 107

Ugust, 195 Set ie the the leno) Be Sure trols the - Point depends d if you \dcasting antenna, get. In ote port. ure on 4 long and on for an ible with ‘olled up enna, © ; just as . piece of k or lake are not id can be re on the » OF you round. will give on. and if rin your able set, with the ry. ne x : Summer’s the Time to sages can be finitely, German) nd ona ans of a | power- n inten- npulses. is mag- literally metized t a soft netized, lf. The pressed lephone ide. S finished th com- made of used for articles. been developed by the U. S. a eveloped by the U.S. Navy August, 1925 Overhaul Your Set (Continued from page 68) ossible, means that either the plates gre badly sulphated or that the positive plates are going to pieces. A storage A pattery can be overhauled, but it is practically as economical to buy a new battery. ; The sound-producing part of . your equipment—the head phones and loud- speaker—should be left strictly alone. Do not try to take them apart or try to ad- just them except, of course, for the usual spacing adjustment fitted to many loud- speakers. This rule does not prevent you from carefully inspecting the flexible cord, and if you find the fabric broken or frayed, the whole cord should be replaced. Like any other piece of delicate appa- ratus, a radio receiver responds to intel- ligent care and it pays to watch for troubles that may stop your reception gome evening just when you are trying to show friends how well your set works. Resistance of Water Found HE resistance of water to electric currents increases in the same mea- sure as its purity. This does not mean, however, that absolutely pure water is an insulator. It has been determined that chemically pure water offers a resistance to electric current which is 45,000,000,- 000,000 times that of copper. A column of pure water .039 inch long and .039 inch square in cross section offers the game resistance as a copper wire .039 inch square in cross section and 27,000,- 000 miles long—more than 100 times the distance from earth to moon. What Becomes of Pins? 'T SEEMS almost incredible that each person in the United States uses 200 pins a year, yet according to the output of the 10 large factories supplying the great demand for pins in this country, the United States now uses more than 20,000,000,000 pins a year. Ants do not like castor oil, for Brazilian agricultural experts have found that the slowly burnt seed of the castor-oil plant produces fumes that not only kill the ants, but prevent the nest from being reinfested. REMAINS of a hitherto unexplored pre- historic city of the cliff-dwellers buried under water when Roosevelt Lake was formed by the erection of the great Roose- velt Dam were exposed by recent droughts which lowered the lake level. PaRT of the heart muscle of an unborn chicken has been kept alive in a test tube for 14 years, according to the recent state- ment of Dr. M. J. Sittenfield of New York. FRENCH chemists have developed an artificial resin from which panels for radio sets are to be made. A NEW ‘air-cooled engine for small air- planes to be flown from ships at sea has POPULAR SCIENCE MONTHLY Balkite Battery Charger. Cnarges 6 volt “‘A”’ storage batteries. Price $19.50 West of Rockies $20 In Canada $27.50 An unfailing 119 Balkite ‘‘B”—re- places “‘B”’ batter- ies and dry cells. Operates from light socket. Price $55 . In Canada $73 power supply for both circuits. Hereat last is an unfailing power sup- ply for your radio set. Balkite Radio Power Units furnish constant uni- form voltage to both “A” and “B” cir- cuits and give your set greater clarity, power and distance. The Balkite Bat- tery Charger keeps your “A” storage FANSTEEL battery charged. Balkite“B” replaces “B” batteries entirely and furnishes plate current from the light socket. Both are based on the same principle, are entirely noiseless, and are guaran- teed to give satisfaction. Sold by lead ing radio dealers everywhere, alkite po Units BALKITE BATTERY CHARGER — BALKITE “B” PLATE CURRENT SUPPLY Manufactured by FANSTEEL PRODUCTS CO., Inc., North Chicago, Illinois — rere Oye NK CARTRIDGE PISTO JOHNSON SMITH & CO, Dept. 400 Racine, Wis. Have You AN INVENTION? If so the WORLD PROGRESS will show you how to Protect and Profit From Your Ideas Sample copy free. One year’s subscription 40c. Send for free book “WHAT TO INVENT” containing Suggestions to Inventors as to Inventions Needed. We invite manufacturers to address us regarding inventions they want. WORLD PROGRESS PUB. CO., INC. Room 202 Victor Bidg. Washington, D. C. Length closed 3% in. This clear, accurate, powerful 6 Power Pocket Telescope (Genuine Wollensak) $2 Postpaid with 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 not thoroughly satisfied. BOSTON SPORTING GOODS CO. Dept. Q, 80 Boylston St., Boston, Mass. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17. OF BROS.& CO. fi8 DIAMONDS WATCHES CASFior CREDIT SoZ SEND FOR CATALOG a ¥A— Over 2,000 bargains in Diamond-set a Jewelry, Watches, etc. Sent pre- CANS) paid for your FREE Examination. R\ Catalog explains everything. ={ “\ Money back if not satisfied. ve WRIST, ~ WATCH ILTON No, 992, 21 ene. Gold Ried 34. Voe ee ree 8 Sere Hors td eaeerecdl in tale, OB ment of $5.50, thon *122a Week LOFTIS BROS. & CO, National Jewelers Dept. C871 108 N. State St., Chicago, til. Stores in Leading Cities RADIO FANS—Kiosdey night trom 71073 Friday night frem 9:30 to 10, Centrai Standard Time. Loftis Bros. & Co.’s hour of music.

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POPULAR SCIENCE MONTHLY ‘Brdlestat PERFECT FILAMENT CONTROL for ALL Tubes without change of connections fe a ial Buy your Bradleystat Angee from nearest dealer Improve your Radio Sef with noiseless filament contr . ‘Tre present trend in radio receivers is toward greater refinement in tone quality, selectivity, _and simplicity of control. This accounts for ne growing popularity of the Bradleystat and other Allen-Bradley periect radio devices. The graphi e disc construction eliminates the scratchy, noisy operation obtained with wirerheostats,and it pros vides an unequaled range of control for all tubes | The “one-hole mounting” and the small size of the Bradleystat permits quick and easy substitu tion for other rheostats. Try a Bradleystat, tonight, and enjoy the ileal : perfect control that makes tuning a pleasure. ~ Allen-Bradley Co. Electric Controlling Apparatus 293 Greenfield AB Milwaukee, Avenue Wis. Manufacturers of graphite disc rheostats for over twenty years y? Bradley Co. 1 293 Greenfield & © venue Milwaukee, Wis. Ke Please send me your g — Oo latest literature on the @ | 4 } Allen-Bradley line of ’@ radio devices, Yes on es we en on es 08 GS Om em % © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 17. Printed by Art Color Printing Co., Dunellen, N. J.