Popular Science Monthly 1924-02: Vol 104 Iss 2

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saa JAN 1 1 1924 PERIOD: AL Rous. , : Teaer. or micu, ©5°2 FouNDED MoO ESRUARY Most Wonderfully Illustrated Magazine in the World a @

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2 | PopuLaR SCIENCE MONTHLY Most Wonderfully Illustrated Magazine in the World FEBRUARY, 1924; Vol. 104, No. 2 25 cents a Copy; $2.50 a Year I Published in New York City at 225 West Thirty-ninth Street | ns ROM Seattle comes an interesting query: F “For some time I have been working on an idea that I believe will lead to an important scientific discovery. But I am dis- couraged because my friends give me the laugh. Is it worth while to keep on trying?” The writer says his investigations show the world has a real use for his product and that it can be manufactured at a reasonable cost. And, he adds, he has the mental equipment to see his idea through. * * S IT worth while to keep on _ trying? Turn to: page 31 of this issue. Read Mr. Francis Jehl’s story of Edison. People, scien- tists of repute and his friends, jeered at his idea of an incandescent lamp. And even as they jeered he was lighting his little work- shop with his lamps. Today the world that jeered cheers at the Mention of his name. to face derision. In Next Month’s Issue My Fellow Scientist —The Rat—The fas- cinating story of how a scientific investigator, by experimenting with rats, discovered valuable new facts about diet and its relation to health and longer life. Private Conversations by Radio —A glimpse at approaching marvels of radio communication, as forecast by Jack Binns, America’s foremost writer on radio subjects. Mechanics in the Jungles — The start- ling adventures of Capt. Frank Hurley, noted British explorer, whose knowledge of mechanics proved an invaluable aid in the wilds of New Guinea. Your Headlights and ‘Your Safety — Simple tricks of adjustment that will insure your car against disaster in night driving. Success in the Backyard Garden — An expert’s timely suggestions for planning, planting, and growing the summer crop of vegetables. And 200 other fascinating articles and pictures CIENTIFIC achievement and inventive ac- complishment frequently mean the ability It is human nature to oppose that which we do not understand. Worry over the sneers of the heedless only wastes the spirit’s substance. Such worry only increases your problems and _ leaves you weaker to handle them. Refuse to heed such taunts and they will cease to annoy you. * * POOR inventor once waited forfour hours outside the office of Commodore Vander- bilt, the railroad mag- nate. He had an in- vention he wanted to sell for $10,000. Fi- nally Vanderbilt said: “Tell that man I have no time to waste on fools.”” The inventor was George Westing- house. His invention was the airbrake. Such a rebuff might have chilled the heart of a weakling. But West- inghouse believed in his idea. And, it is said, Vanderbilt’s sneer only %* %* EMEMBER Robert Fulton. He and his steamboat were the butt of countless jokes. A widely known British marine engineer “proved” by mathematics that the idea of running a boat by steam, independent of wind, was “preposterous.” But before the ink was dry on his published forced him into grips with his problem, the conquest of which brought him millions. * * [F YOU are sure of your idea, have the curiosity to find out about things and the energy to overcome obstacles. It is always worth while to keep article, a steamboat had landed in Eng- land. The laughter of skeptics infused zest into Fulton’s task, and it was he who had the Jast laugh. | POPULAR SCIENCE MONTHLY Issued monthly. Single copy, 25 cents. Yearly subscription to United; States, its possessions, and Canada, $2.50; foreign countries, $3. Entered as second-class matter Dec. 28, 1918, at the Post Office at New York under the act of March 3, 1879. Entered as second-class matter at the Post Office Department, Canada. Printed in U. S. A. Copyright, 1924, dy the Modern Publishing Co. The contents of this magazine must not be reprinted without permission. H. J. Fisher, President; R. C. Wilson, Vice-President O. B, Capen, Secretary and Treasurer on trying. Concen- trate all of yourself on a worthy purpose. Don’t be too modest. Close your ears to ‘jeers and say to yourself—IT CAN BE DONE!

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lode! VI t, one ctor. bining =tector to plug up for pt the th the 2t pro- autiful stru- y of POPULAR SCIENCE MONTHLY SO Go PJD > weed ee mm reo per pee, }eea Pua pe © as =e @« eet ™=eee ‘es Ce re 6 ae LAA. Bged me & © 6 jae of { ©OK.&H. SIR WILLIAM BRAGG, one of England’s leading scientists, at work in his laboratory at Uni- versity College, London, with his wonderful instrument called the ‘X-ray spectrometer,” by means of which he is attempting to fathom the secrets of the mighty, infinitesimal atom. He is one of the world’s scientists who, through researches into the con- struction and action of atoms, are revolutionizing the study of phys- ics, making it possible to study the nature of the universe from the smallest particles of matter DR. LEANDER TOMARKIN, a young Swiss biologist, recently announced the discovery of a cure for pneumonia. He calls his remedy “antimicrobum,” a chemi- cal compound that is said to have reduced pneumonia mortality from 35 to 2 per cent. He is shown below in his laboratory at the Holy Ghost Hospital in Rome, where he is reported to be testing a remedy for tuberculosis Dr. Leander Tomarkin the Hour bd VEE: ¥ FRIDTJOF NANSEN, D.Sc., D.C.L.; Ph.D., F.R.G.S., world-famous Nor- wegian arctic explorer, author, educator, scientist, diplomat, and winner of the Nobel peace prize in 1922. He now is a leader in organized effort to rehabilitate the war-devastated nations of Europe, and in this interest recently visited the United States on a lecture tour SAMUEL WESLEY STRATTON, B.S., D.Sc., new president of the Massa- chusetts Institute of Technology, and for 21 years director of the United States Bureau of Standards, declared, in a recent statement, that “‘there is a great and growing need for men trained in methods of investigation as applied to the industries,” and that “we need men skilled in physics and chemistry, who can appreciate problems that are to come with industrial progress.’”? On the en- gineer and scientific investigator, he said, depends largely the commercial and in- dustrial progress of the United States In Science CHARLES GREELEY ABBOT, D.Sc., astrophysicist of the Smith- sonian Institute, Washington, D. C. With the aid of a giant, 100-inch reflector at the Mount Wilson observatory, California, he has succeeded in measuring the heat of stars to the hundred millionth of a degree. Doctor Abbot is shown above with a sensitive heat-measuring instru- ment called the “pyrheliometer,” which he invented for his re- searches. It is based on the same principle as the little black-and- silver vanes, revolved by light, often seen in opticians’ windows J. WALTER FEWKES, Ph.D., LL.D., director of the Bureau of American Ethnology, Smithsonian Institute, Washington, D. C. He has contributed largely to our scientific knowledge of the races of men that have inhabited the American continent, especially the Hopi Indians and Cliff Dwellers. He is shown below examining a piece of bread more than 500 years old, dug from Indian ruins ye Dr. J. Walter Fewkes »ee* P@@q ats LEA keene meed bees need -ee-s

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POPULAR SCIENCE MONTHLY SUMNER N. BLOSSOM, Editor February, 1924 Edison, the Man An Old Friend’s Intimate Recollections of the Great Inventor OU probably read in the newspaper the other day that Thomas A. Edison had sent for an old Michi- gan fiddler, Jep Bisbee, to come East so that phonograph records might be made of the jig tunes he had played for Edison, Henry Ford, and Harvey Firestone when they were on their camping tour last summer. For me there was a great deal more in that story than the papers printed. That Edison had not forgotten a promise made half a year ago to a casual acquaintance of his vacation jaunt who wanted to hear his tunes on a phonograph, told me that he still remains the same thoughtful man he was 45 years ago, when I started working for him as a lad of 18 in his his- toric laboratory at Menlo Park, N. J. great-hearted, - considerate, We read so much of Edi- son as the electrical wizard and the world’s greatest in- ventive genius, that most of us, I fear, have lost sight of the fact that he is a human being as well—a _broad- minded, sympathetic, kindly man who reads the news- papers to see what his fel- low men are doing, who en- joys a clever joke and a good cigar, and who derives as much wholesome fun out of life as any man alive. A Thoughtful Man That little incident of the old Michigan fiddler is typi- cal of the Edison- I know, the man who always is look- ing out for others and trying to make them happy. It brought to my- mind the memory of my first meeting with him and thesurprise I got to find him the very op- posite of the-cold, austere _ scientist I had pictured him. I had been reading law at the office of Grosvenor P. Lowery, counsel for the - Western Union Telegraph © Company. -He noticed that my principal*interest lay in briefs concerning electrical patents. One’day he asked me about this, and I: ad- mitted that I was more in- terested in electricity than By Francis Jehl RTY-FIVE years ago, Francis Jehl, then 18 old, went to work for Thomas A. Edison as-a labo- ratory assistant. Mr. Edison at that time was experi- menting with the incandescent lamp and had a staff of seven men. Mr. Jehl is the only survivor of that staff, the only man living except Mr. Edison who saw the birth and development of the lights we all use today. Mr. Jehl has been in the Edison organization since the day in 1879 when he was chased into Mr. Edison's office . by a pet bear the great inventor kept in the yard of the lamp works. He now is connected with the Edison Museum in New York City. He has been in constant touch with America’s greatest inventor for nearly half a century, and knows his chief as few other men are priv- ileged to know him. inlaw. Mr Lowery knew Thomas Edison as the inventor of the stock ticker, the quadruple telegraph, and other devices bought from him by the Western Union. He was convinced of Edison’s genius and om, te Me long, awed. Lahrer Q | An unusual portrait of the great inventor as he appears today had been quietly enlisting the financial backing of such men as J. Pierpont Morgan, E. G. Fabbri, Robert -F. Cutting, and Henry Villard for Edison in the latter’s experiments on a new type of electriclamp. He gave me a letter to Edison, and one day I took a train to Menlo Park to present it. Menlo Park, then as now, was an obscure little hamlet on the Pennsylvania’ Railroad, a few miles from Rahway, N. J. People who have traveled on Pennsyl- vania trains between New York and Philadelphia doubtless have seen the station as they whizzed past. The main street was all but deserted that day as I hurried toward the white-painted, house that was Edison’s laboratory. I was thrilled, and more than a little two-story frame I was about to see the greatest inventor in the world! More than that, Mr. Lowery had told me that Edison was agreeable to my joining his laboratory force, if I could qualify. You can imagine how my heart was thump- ing; how I was besieged by fears and misgivings as to the sort of impression I might make on Mr. Edison. Edison’s “Pet Dog’ As I approached the front porch I caught sight, of a great shaggy mass lying under a giant hickory tree beside the house. “Ah!” I thought. Edison’s pet dog!” It occurred to me that I might win some slight favor with Mr. Edison if I could make friends with his dog, so I thrust out my hand to pat the animal. The next instant I was rushing up the stairs of the laboratory, the worst scared young man who ever had entered the place. For the animal un- der the tree was a brown bear. It was chained there; but I didn’t take time to ascertain that fact. I just ran. I forgot all my carefully rehearsed speeches, forgot everything I had planned to impress Mr. Edison. I 31 “Mr.

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32 POPULAR SCIENCE MONTHLY me eee me NY ee — — = — The historic laboratory and lamp factory at Menlo Park, N. J., where in 1879 Edison and his assistants manufactured the. first incandescent lamps in the world dashed into his laboratory, pant- ing and dishevelled, looking ap- prehensively behind me for the beast which I felt must be at my heels. I had intended to be dignified. Instead, I was funny and, I fear, ridiculous. Mr. Edison laughed heartily when I burst in on him, but it was a laugh that endeared him to me forever—a sudden, swift revelation of his character. There was no ridicule in the laugh; no trace of enjoyment of a boy’s embarrassment. It was just a wholesome, hearty, spontaneous burst of merriment such as any comical happening might cause. “Well, son,” he said, ‘‘did the bear chase you in? Don’t let that bother you—you’re not the first one.” In an instant I was at my ease, and within a very few minutes arrangements had been made for me to join Mr. Edison, an association that has continued without interruption to the present day. Six others besides myself were at the laboratory, aiding Edison in his experi- ments with the incandescent lamp. He was entering his thirties then—an earnest young man with a determined, purposeful face, crowned with that same mop of hair that is silvery now. We worked. Mr. Edison had a faculty for getting things done and for keeping his force inspired with the same enthusiasm that actuated him. . Yet not one of us ever thought of him as “‘the boss.”” For he was no driver. He had—and has—executive ability—a faculty for handling men in a degree pos- sessed by no other man I ever have met. Sometimes it would take half a day to “8 ‘otis j ln 1a named “Dot” and ‘‘Dash.”’ Edison, the inventor’s father. article, is the third man from the left in the top row A group picture of Edison surrounded by members of his family and his laboratory assistants, taken in 1879. Beside 4 him are his two children, Marion and Thomas, Jr.—nick- a joke. The Edison of 1879, described by the writer as ‘‘an earnest young man, wit! a determined, purposeful face’ The white-haired man is Samuel Francis Jehl, author of this PSter.. Here, 45 years ago, the writer of this article, then a lad of 18, went to work for Edison and took part in his early struggles for recog- nition and commercial success mount a filament in a lamp—and then it wouldn’t work. The man who had done the work often would be discouraged to such a point that he was ready to give it all up—to leave the de- velopment of the incandescent lamp to somebody else with hardihood enough to continue such unsatisfactory work indefi- nitely. That mood, though, never lasted long when Mr. Edison entered the scene.. His eyes would twinkle as though the un- successful experiment were just “Well, now,” he’d say, ‘‘we’d better try that again. Maybe this time we'll find out what’s wrong with it.” And that’s the way the incandescent lamp was invented—experiment after ex- periment; tireless search for the reason for failure; attempts to correct mistakes. And always the indomitable spirit of Edi- son triumphed over setbacks and discour- agements, inspiring his assistants with faith in his purposes and confidence in his ultimate success. You have read that Edison is a tireless worker. No man ever worked harder and more relentlessly than he did in those early days. And by the magic of his per- sonality he kept us all working with him, heedless of discomfort or fatigue, inter- ested only in the work we were doing, and reluctant: to leave it -until -it. was: done. Night after night we stayed at the labor- atory until the gray light of the new day drifted in through the windows. Mr. Edi- son would toss a few books on a bench or (Continued on page 140) BSS TT

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POPULAR SCIENCE MONTHLY 33 Exploring World’s Greatest Cavern One of the great cham- bers of the Carlsbad Cave, shown above, is more than half a mile long. Columns range from the length of a needle to heights greater than 100 feet. The ceiling is more than 300 feet high The slow seep and drip of mineral solution through incalculable ages shaped the weird archi- tecture shown below. Drips from the vaulted ceilings built up the dark stalagmite rising like a pillar in the fore- ground, and the stalac- tites that hang from the ceilings like huge icicles ITH fantastically beautiful rock formations and _ cathedral-like chambers glittering in a hundred shades of color, this vast cavern near Carlsbad, New Mexico, is believed to be the largest ever discovered. Although its existence had been known since 1901, when swarms of bats were seen to fly from a hole in the side of a hill, it was only recently that its interior was explored by scientists of the United States Geological Survey. A small party, headed by Dr. Willis T. Lee, entered the lofty chambers while seeking to discover why waters im- pounded in dams along the Pecos River disappeared underground. One of the enormous rooms was found to be half a mile long and a quarter mile wide. Except for millions of bats, the great Carlsbad Cave shelters no animal nor vegetable life. In the early morning and late afternoon the echoing darkness is vibrant with the beating of their wings as they dart among the grotesque formations Below are shown two massive columns rising to a height of 70 feet above the floor of the cavern. They are dark green in color. Unusual formations of smaller stalagmites, ranging in color from light cream to dark brown, are shown at the left center Se Sl Saeed - Pe Cage ideation on SS ape pe eet snes Sea te ot OLS EMS RRS SEE SEER NELL LLED OP COLLIE EEC oie RT eT OR sete ns RE — tess nC eee ~aprrare ont Pa yt xm Li pieeta eet 4 os Poa gre ase ! B 4 hy i Bk + He re * eS 5. 48 AY a i SRE He wa sya ah hai a8 ET

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ee acre EY ae an a perenne — 34 POPULAR SCIENCE MONTHLY uA How the Followplane, gigantic seaplane cruiser to be constructed at Cleveland, Ohio, will appear when completed. This drawing is based on the designers’ plans. The giant liner will be 170 feet long, and will be designed to carry 100 passengers and 2!4 tons of express freight Whole World in Race for Supremacy in the Air By Donald Harris HE swiftly moving airplane of today, with its one or two spe- cially trained occupants, soon may share its dominance of the air with the slower-moving commercial liners and the more versatile helicopters of tomorrow, just as the specially constructed racing automobiles of 20 years ago moved over to give road room to the utilitarian cars of today. Epochal Advances in Aviation Epochal advances in aviation are in progress. The air flivver already is here. The helicopter and the gigantic air cruiser for freight and passengers are on the way. In France récently M. Oehmichen flew for nine minutes in a helicopter designed by him, rising 35 feet and circling a course. This set a record in vertical flight, more than trebling the best previous feat. A few weeks later, in another type of helicopter, the Marquis Pescara accomplished a flight of nearly six minutes. Throughaut France heli- copter development is receiving the en- thusiastic attention of the most eminent aeronautical de- signers. In England and Germany, tiny planes analogous to low-priced automo- biles enjoy the focus of expert attention. In the United States, birthplace of the airplane, giant planes, such as the TILTING WING FOR FORWARD MOTION army’s Barling bomber, and great dirigi- bles; such as the navy’s Shenandoah, have become the goal of our most distinguished designers. Among the latest developments in these countries, remarkable are the Halley helicopter in France, shown on the cover of this issue, and the gigantic Followplane aerial cruiser to be construct- ed in the United States, the design of which is shown in the drawing at the top of these pages. The new helicopter designed by Charles Halley, a noted French engineer, con- ceivably may revolutionize aeronautical design. Although this machine exists only as a model, the radical yet apparently sound departures embodied in it have engaged the keen attention of experts everywhere. A_ successful helicopter would obviate the need for flying fields. Helicopter hangars on _ office-building roofs would make it possible for business men to commute 100 miles by air and to land the distance of an elevator ride from their offices. On the Halley machine two bell-shaped wings are attached to a car resembling an airplane fuselage. Two motors in this car drive two propellers revolving in a aR eye IN ABOVE £ a, vertical plane on each side, drawing air from above the machine and driving it against the curved under surfaces of the wings. By deflecting the air downward, the wings exert an upward push. .Com- bined with the suction obtained by draw- ing air from above, this push is said to raise the craft swiftly and vertically. Tilting the wings ejects the air from the propellers rearward as well as down- ward. This, the inventor claims, pro- duces sufficient force both to keep the craft aloft and to drive it forward. Directed by Controlled Air Currents In addition to the steering lever, there is a vertical control lever that opens and closes openings in the center of each curved wing. When these holes are opened, part of the air driven against the wings will escape, lessening the vertical propulsion. A wider opening is said to cause the machine to hover, practically motionless. And, finally, a still wider opening, the inventor claims, will cause the machine to descend. It is claimed also that the parachuteshape of the wings makes the Halley helicop- ter comparatively safe, even if the motor should fail. WINGS DEFLECT AIR DOWNWARD The huge Follow- OPENINGS plane air cruiser, rE TTON VERA designs of which were completed re- nat ik Ee AIR AGAINST CU cently by. Thomas R. MecMechin, once Diagrammatic views, side and rear, of the revolutionary parachute-like helicopter Aatenel by Charles Halley, French engineer, and pictured on the cover of this issue. Its principle con- sists of drawing air from above and driving it against the wings to produce upward motion a Zeppelin en- gineer, and. Lt. Ar- thur Dennison, for-

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mer United States Army designer, truly is a remarkable machine. This gigantic freight and passenger plane, by far the largest ever seriously projected, is to be built at Cleveland, Ohio. It is to be all of metal, 170 feet long, 26 feet from keel to top. It will contain 2500 square feet of floor space and will fly with six staggered pairs of wings, each with a span of 61 feet. : Six engines, of 900 horsepower each, will drive six propellers. These engines will be paired, only two operating at the normal cruising speed of 125 miles. The other four will be reserves. It is estimated that a speed of 200 miles an hour could be attained with all six engines operating. This aerial giant will be a seaplane, capable of rising from and landing on water. The great length of the wings and their staggered arrangement, combined with the weight of the plane, is expected to allow the machine to travel through severe weather with no more than a very slow roll. All combustible supplies will be carried in an airtight compartment, which can be flooded instantly with car- | bon dioxid in event of fire. POPULAR SCIENCE MONTHLY The engines embody numerous radical departures in internal combustion design. They will burn fuel oil, a feature that is expected to reduce their operating cost. It is claimed further that they cannot baekfire. Power is transmitted to the propellers through a hydraulic system. When completed, the great air liner is expected to shorten the traveling dis-

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eSSE4 RY Dy ; tance from New York to London to less than 24 hours, at the normal cruising speed of 125 miles. An American states- man couldleave Washington one afternoon and keep a speaking engagement in Lon- don the next evening» Chicago and New York would be only six hours apart. Itis estimated that a $35 fare would make the craft pay a profit on this route. For the transatlantic journey, a fare less than $150 would be adequate, it is be- lieved. At least 100 passengers and 2144 tons of express freight could be carried. Staterooms with berths will make night travel feasible, and dining ac- commodations will be provided. Pas- sengers will not need to remain in their seats throughout the journey, as in small passenger planes. Even dancing space could be provided, the designers say. Because of the all-metal construction and fireproof compartments, smoking can be allowed. The Halley helicopter and the Follow- plane both represent new mile posts in man’s swift conquest of the air. Other aerial models await only the working out of constructional details. ‘

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The new helicopter invented and operated by M. Oehmichen, shown in flight during a recent trial near Valentigney, France. The machine rose 35 feet on a citcular course, remaining in the air for nine minutes, breaking all previous records for vertical flight. The inset shows the inventor at the controls A SANE ST “5a, ne = + SREY Bar ate Sit octet avr sce be 0 2. Site Sle AeA os vie < ~ EET LN EAR LER ROET ONS 7 . ' ‘ e “ seta A

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36 POPULAR SCIENCE MONTHLY Your Senses—and Common Sense Second Article in from a blind man, who keeps a news- stand near my home. When I tell him what papers and periodicals I wish, without hesitating he selects them from the rack and hands them to me. He always makes correct change for me instantly from a pocketful of coins. In the several years I have been patronizing him I never have known him to make a mis- take. I cannot but admire the skill and accuracy with which that blind newsdealer, despite his in- firmity, carries on his little busi- ness. People often explain the ap- parent mystery of it by saying that nature has compensated him for his loss of sight by sharpening his other senses, especially his hearing and touch. But that is not true. Under test by the esthesiometer, an instrument for estimating delicacy of touch, a blind man is shown to be no more sensitive than the normal person. For example, the blind man is not at all superior in recognizing, as two separate sensations, two needle points that prick his skin at points very close together. He has learned, though, to pay attention to minute differences in feeling and to recognize them, and he knows through practice what he expects to feel. Thus he is able to differentiate unerringly the pennies, nickels, dimes, and quarters in his pocket, and the magazines and news- papers on his stand; things which all of us could do quite as well if only we would concentrate on using our senses as they should be used. How We Neglect Our Senses Neglect of the unused resources of our senses is one of the great handicaps we place upon ourselves. Have you ever taken your watch from your pocket, glanced at it, and then, a few seconds later, found yourself unable to tell an- other person the time? Can you at this moment, without referring to your watch, write down the numerals on the dial exactly as they appear? Try it and see. Unless you have heard of this test before, I venture to say that in the thousands of times you have looked at your watch you have failed to observe that there is no numeral 6; that the place that numeral would occupy is filled by the second dial. Again, if there are Roman numerals on your watch, I wonder if you have ob- served that instead of “IV” the numeral is inscribed “IIII’’? Do you know the color of the eyes of the person who sits beside you in your office or stands next to you in your shop? Can you tell with what words the govern- ment marks the value of a 25-cent piece, or on which side of the coin they appear? These are things that you have had ] BUY my newspapers and magazines Bereft of sight and hearing since childhood, Helen Keller (at the right) and Willeta Huggins, 17-year-old Chicago girl, have achieved distinction by developing the sense of touch to an amazing degree. They are shown above in conversation. Miss Keller “‘hears’”’ by placing her finger tips on the girl’s lips, while Willeta understands what Miss Keller says by placing the finger tips on her chest and sensing voice vibrations hundreds of chances to observe. You may say they are not important; yet ob- serving them in a way that would imprint them indelibly on your memory is a process that requires no effort if you have trained your senses to work for you as Nature intended they should. Such train- ing in observation is an invaluable aid to successful achievement. If you have not trained your senses to Testing an automobile engine in the plant of a Detroit automobile company. By concentrated “The Story of the Mind” By James J. Walsh, M.D., Sc.D. record accurately every impression they receive, you have placed an insur- mountable barrier before the store- house of your mind. For the senses are the gateways of knowledge; the only entrances by which the mind can receive the stimuli, without which, as I pointed out in the previous chapter of this series, the mind will not work. Only through impressions re- ceived by your senses can your brain store up the facts and infor- mation that mean skill at your trade, expertness at your profes- sion, scholarship in education, @ trained mind for life. The oldtime philosophers had a maxim well worth recalling: “There is nothing in the mind except what was beforehand in the senses.” What they wanted to emphasize was that we are not born with ideas. We have in- stincts designed to enable us to live, and reflexes intended to pro- tect us against dangers in early life; but we have noideas. They have to be acquired. It would be mighty handy for some of us if we could inherit the education of our parents, and, beginning with that basis, add more. Dr. Oliver Wendell Holmes praised Emerson as the seventh genera- tion of an academic family, yet that hereditary quality did not add to Emer- } aii a ee | training of his sense of hearing, the skilled mechanic who makes the tests has learned to detect the least flaw simply by listening to the sounds of the running engine through a stethoscope

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son’s possibility of mental de- velopment, much less confer education on him at birth. His environment, undoubt- edly facilitated his education, but his heredity did not. Your father and mother both may have known Greek well, or mathematics; but that will not make it any easier for you to learn either mathematics or Greek. On the other hand, your ancestors may have been un- educated drawers of water, hewers of wood, or tillers of the soil for many genera- tions; yet it is pos- sible for you to make ducks and drakes of the scion of an aca- demic family who chances to start his education at the same time you do. In other words, what you know, what you learn, what you eventually amount to, are a result of what you yourself acquire through your senses. Hence, the necessity for training the senses. ‘In early life the untrained senses are almost useless. The child reaches out to grasp the moon because its senses have not yet been trained to perceive that, though the moon is very bright, it is too far away to be touched. The Chinese Train Their Senses A little later in life this same child, as a result of experience and training of the senses, may be able, with one glance at a skyscraper, to tell you how high it is within a foot or so. They say that when a Chinese carpenter is summoned to make repairs, he looks at what has to be done, then goes back to his shop and cuts the boards so that they will fit exactly into the portion that is to be repaired. He has trained his sense of sight to give him exact knowledge. I know a real-estate man who can go through a large building and tell you, when he comes out, the exact size of the rooms and how they are situated. An exceptional man? Not at all. He merely has trained his senses to POPULAR SCIENCE MONTHLY Tea tasters employed to grade imported teas and for the collection of customs duties, require a highly developed sense of taste. perceive things accurately, and his mem- ory to retain whatever they taught. Go into a telegraph office and listen to the busy clatter of the receiving instru- ments. It all seems a meaningless jumble of sounds to you, yet the operators sitting beside the instruments are ticking off on their typewriters the meaning of those sounds in ordinary English at the rate of more than 100 words a minute. Can they hear any better than the rest of us? Not at all. On the contrary, their hearing often is worse than the average, because the constant effort is a strain on the delicate hearing apparatus. They merely have trained their sense of hearing to catch the meaning of those sounds. After all, this is no different from learning a foreign language. Above: A _ psycho- logical test in judg- ment of space varia- tions for the young man who is to enter an engineering shop At the left: Inspect- ing finished artificial leather as it comes from the coating ma- chinery in a factory at Newburgh, N. Y. The trained vision of the girl inspector de- tects the smallest flaw in the moving sheet of the fabric They command high salaries accordingly 37 When the telegraph was invented, a cumbrous printing apparatus for record- ing the signals went with it. This was extremely slow in operation. An enter- prising telegrapher trained his sense of hearing until he could recognize the differ- ence between the sounds of dots and dashes and_ those made by the ma- chine, and thus read the message correctly. Concentration It proved an im- portant discovery and trebled the value of the telegraph at once because it permitted messages to be ex- changed three times as rapidly as before. This is the sort of thing that concen- trated attention to any sense will achieve. There is a very credible story of a country storekeeper who was able to tell the different solid colors—at least so far as red and blue and white and black were concerned—by touching the cloth. It seems almost impossible that such deli- cacy of touch could be acquired, yet there are considerations that make us ap- preciate exactly how it is done. If you were to take small squares of red, blue, white, and black cloth of the same weight and material and spread them out on a windowsill over a freshly fallen layer of snow, with the sun shining on them, the snow beneath the four different colored squares would melt in varying times. _The black cloth would be the first to touch the windowsill. The reason for this is that black absorbs all the rays of the sun and reflects none; therefore it takes up more heat than the other colors. White reflects all the rays of the sun and not a little of the heat. That is why light-colored clothes are more suitable than dark clothes for wear in the summertime and in tropical countries. Red absorbs more light and heat than blue. Can You Feel Color? The storekeeper had learned to differentiate among the four colors of cloth by the differences in tempera- ture which they acquired from their varying power of absorbing and re- flecting heat. It required extreme concentration of attention to accom- plish his purpose, but then concen- tration is the only key that will un- lock the gateways of knowledge that lead to the mind through our senses. What that man did, you yourself have done many times in less degree; but, because you can see, because the necessity for further development of your sense of feeling did not impel you, you failed to acquire the excessive refinement of sense that made this merchant’s feat seem so remarkable. Groping in your desk in the dark, for example, you never would mistake for an ordinary pencil a hollow tube of metal, shaped like a pencil and | b bh f oe ce ee * ee se asa nee wa io eS Pe io BS ET ss cingage tere Rees = waite Messe stent! F pt oa ends ERS Te ese EA hasnt DE Se eed RS BER SED RE ae # RR ita LENE KT , = restnine sat, sg z ha gant NERS A en ay pe tam aa he ah

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pereaceseemiy es emesesomaaa phe ge eat et ete oe apis fies i athe SEES Seibel meee poeta aa at —e SF ese 38 possibly of the same weight. The metal feels distinctly colder than the wood of an ordinary pencil. Similarly, you would recognize, at the first touch, the difference between a conventional pencil and a patent metallic pencil. You can tell at once whether an object is of metal or of wood, of stone or of composition, by the difference presented to your sense of touch. Important though your eyes undoubtedly are, you do not de- pend on them if you wish to de- termine whether a column in a church is of stone or of some composition. You touch the column with the tips of your fingers and recognize almost at once the difference, through the intensity of the cold sensation presented to you. Of course, there is no actual difference in temperature. Analyzing Touch Sense If a pencil and a metal tube have been lying on your desk together for several hours, they are both of the same tempera- ture—that is, the temperature of the room. But, since metal is a better conductor of heat than wood, the metal tube carries heat away from your hand faster and you note this fact at once. Hence the immediate recognition of the difference between them, though they may be of the same shape and weight and present POPULAR SCIENCE MONTHLY We have a sense for cold, another one for heat. We may lose one without losing the other. We have a sense of pain, too, which we may lose without losing our sense of contact. Some years ago I saw a man enter the Salpétriére Hospital in Paris suffering from a badly burned finger and thumb. He had become engrossed in conversation with a friend and had per- senses of touch, each no more connected with the others than the eye nerves are connected with the hearing. This discovery is of real practical value to us. It shows us that what we call our sense of touch, which we regard simply as a blunt purveyor of sensations, actually is capable of being trained to bring us the most delicate details of information and to serve as a highly useful aux- iliary to what may seem the senses of sight and hearing. The powers of the blind news- dealer I have mentioned illus- trate vividly the really amazing possibilities that lie in full use of the sense of touch. Probably more remarkable still is the familiar case of Helen Keller, who, deprived of both sight and hearing by an attack of sickness in babyhood, and _ seemingly fated to remain a hopelessly ig- norant and dependent human being, successfully completed a college course, won a doctorate of philosophy and has achieved distinction as a writer and lec- turer. All of this she accom- plished entirely by means of her sense—or senses—of touch. Triumph over Blindness Laura Bridgman, the young poetess of Buffalo, is another blind and deaf person who has triumphed over the cruelties of ~~ A 4 2 * 2 A. ey bt Vib exactly the same feeling of smoothness to the hand. The same thing is true of the pillar made of plaster and the pillar made of stone. Nature has provided you with ©vu.&U. Mrs. Alice Foote MacDougall, the only woman coffee grading and blending expert in America, at work in her office in New York City. Fifteen years ago Mrs. MacDougall was a penni- less widow. ‘Today she is at the head of a large retail and wholesale coffee business which she built up by her own efforts largely through training and developing her sense of smell nature through training of the sense of touch. It will be re- membered, too, that Homer, one of the first and greatest of the world’s poets, undoubtedly was blind. So was the great Milton. But the usefulness of the sense this wonderfully sensitive and versatile faculty of recognizing different objects through their different physical characteristics, merely by touching them. Such qualities as smoothness, shape, weight, and temperature transmit their individual messages to the touch. Doesn’t this fact cause you to wonder whether what we call our sense of touch may not be actually several senses? This is precisely the conclusion that psychologists have reached as a result of recent research. Instead of the five senses that long-established tradition credits to us, modern psychology says we have actually 25 or more, each inde- pendent of the other, each performing its own individual functions with regard to the assimila- tion of impressions which, when stored away in the mind, become knowledge. Nerve Telephones There are at least 25 differ- ent nerve endings that pick up information at the sur- faces of the body and carry it to the brain, where it is regis- tered. And each of those nerve endings will pick up only one kind of informa- tion for transmission and no other. We have, for example, no less than six senses of touch. mitted a lighted match to burn his fingers. He did not feel the burn, and was unaware of it until he smelled his burning flesh. An affection of the spinal cord had cut off some of that man’s sensory nerves on their way to the brain. Heat brought no sensation to his fingers, although he could distinguish cold, and could tell one famil- iar object from another by feeling them. His case supplied the most startling ex- ample I have encountered of the fact that we have at least a half dozen different I seieseinsrenesenesinenmemersitite nism A psychological test to determine concentration and span of attention. The subject is required to concentrate on one job, at the same time giving attention to other details about him—in other words, to “‘attend to many things at once’—an important requirement for success of touch is not confined to those who are deprived of other senses. I know a cloth merchant who can tell the value of cloth to within a few cents a yard by feeling it. He can tell how many threads it contains to the inch. He knows instantly whether the material is pure wool or wool mixed with cotton; whether it is pure silk or one of the recently invented artificial silks; whether it is loaded with metallic salts that add appar- ently to the body of the material but make it likely to crack and to be short- lived in wearing. He knows the strength ~ of the fiber, whether it is short or long. This knowledge he has acquired only as a result of persistent training, for he en- tered the mercantile field as a clerk and had no previous ex- perience in any other field. His sense of touch is no better than that of the average human being, but he has learned the priceless habit of concentration and attention. Study Your Impressions He has learned to inter- pret aright the impressions his senses of touch receive as he fingers a bit of cloth, and to remember those impressions so that he recognizes them in- stantly when he encounters them again. (Continued on page 145)

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POPULAR SCIENCE MONTHLY 39 Amazing Photos of the Atomic Universe A sh neem nena ey ' 1. Two views of a collision of an alpha particle (helium) with an oxygen atom. The shorter fork shows the trail of the deflected atom. Science, exploring the world of the infinitely small, has found that an atom is a tiny solar system in which concentrated electric charges, called ‘‘electrons,”’ revolve at a velocity of 93,000 miles a second about a central nucleus, as the planets about the sun 4. The passage of X-rays through the air. A narrow beam of X-rays liberates electrons from atoms of matter. In each‘atom there are from one to 92 of thesetiny worlds aor meng 6. Alpha rays in the air from polonium, a radioactive substance discovered in 1898 by Madame Curie. These two spectacular photographs of mysterious radioactive emanations were taken at right angles to each other By courtesy of Sir Ernest Rutherford, F.R.S. Photographs Nos. 1, 3, 5, | . Sir Ernest Rutherford, é , F.R.S., president of the British Association for the Advancement of Science and Yu Muse { bet 5 RO pi ad ARR QA HT Ih 3. Two views showing collision of an alpha particle with a hydrogen nucleus. The left fork shows the track of the nucleus. Scientists say it would take a million times a million times a million hydrogen atoms to equal in size the smallest visible speck that can be weighed in a delicate chemical balance; yet here is an actual photograph of the movement of a portion of such an atom j KL AL o one of the world’s foremost 7 + i 4 authorities on radioactivity. \ ¥ i 5 In his experiments he plays , | j £ with atoms as other men til , play with billiard balls. Lif! a The amazing photographs OE EE reproduced here through his 5.. Two views of a collision between an alpha Courteny,. illustrate his dis- particle and a helium nucleus. Since both have coveries in a world invisible the same mass, the defleétion forks are equal to ordinary microscopes 2. Path of an alpha particle shot out from an atom of radium emanation. Ruther- ford’s experiments have revealed that the rays given out by radium and kindred substances are of three ° different kinds—called ‘alpha, beta, and gamma rays” —and have proved that the alpha rays shot out by radium are none other than atoms cf helium ga. 7. Collision of an electron with a nucleus of an atom and with other electrons—comparable with a collision between our world and the sun 8. A very weak X-ray, showing electrons liberated at an angle with its path. Although an atom is so small as to be almost incomprehensible to man, an electron is far smaller; yet it obeys orderly laws of the universe and 6 by Mr. Blackett; Nos. 2, 4, 7, and 8 by Mr. C. T. R. Wilson ' { i 1 | ae | ae ba i $ ‘ 4 y | ae i) ee ; | if} ? if } 4 vil | qi ‘he ie ; 2 1 ola i i a thee YO en AO - da 2 aa ee oe ee eee

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naddetebemunae iat ay emuctitperes a ticnarmcryes arth tar eS ARETE TSN Pos 40 _ Astronomy from the Cellar How a Busy Man Makes the Stars His Textbook POPULAR SCIENCE MONTHLY An Interview with James Hartness, ex-Governor of Vermont By Raymond J. Brown “y , YHEN I was Governor of Ver- mont, there were times when the affairs of state assumed pro- portions that seemed overwhelmingly im- portant. At such times I would go to my telescope and look upon other worlds; then the affairs of men on earth, their in- trigues, their ambitions, and their en- deavors, became trivial. Then the seem- ing importance of this world, the states and nations of which are marked off by definite, narrow lines, paled into insig- nificance in comparison with the vast worlds that lie beyond us; worlds that have no boundaries; worlds whose infi- nite size we cannot comprehend. Earth's Affairs Seem Insignificant *‘Whenever my troubles get too much for me, whenever I begin thinking that I am carrying a heavy burden, I find solace in my telescope. Properly enough, it is always. the small end of the instrument that points toward the earth. A few minutes’ gazing into the wonders of the skies, and my affairs are reduced to their proper proportion in the scheme of the unfathomable universe. They become inconsequential, unimportant; hence, why should they annoy me?” Thus does James Hartness—prolific inventor, successful selfmade business man, former governor of his state, recipi- ent of honors for useful scientific achieve- ment—describe the unique philosophy of life that has come to him from pursuit of his hobby of astronomical observation “from the human standpoint.” An Underground Observatory Going underground to look at the heavens may seem like a strange anomaly; yet that is exactly what Mr. Hartness does. For on his big hillside estate at Springfield, Vt., he has constructed the strangest astronomical observatory in the world—a subterranean cave of concrete, containing a half-dozen rooms fitted up as laboratory, library, study, office, and retiring and storage rooms. Connecting with his home by a 200-foot tunnel, the cave ends with the observation chamber, a concrete structure from which juts a cast-iron revolving turret that holds his telescope. In this turret, which is an adaptation of the revolving turret of a battleship, Mr. Hartness conducts his studies of other worlds. There he is shielded from inter- ruption and from distraction by annoy- ances of the world in which he lives. His observatory is little short of revo- lutionary from the standpoint of the or- thodox astronomer. In fact, when his first rough plans were shown to astrono- mers and makers of optical instruments, they shook their heads gravely and as- sured him that it couldn’t be done. But Mr. Hartness, who had something more than 100 inventions to his credit at the time, merely listened to the objections and built his observatory virtually as he had planned it. Later he had the satis- faction of hearing from his critics that his instrument produces results that compare favorably with astronomical apparatus of large observatories. In the cosy study of his subterranean retreat, Mr. Hartness, a tall, wiry, grave- faced man, with kindly eyes, told how oe nc tat , laf : zg ay . Ao, Neti ES ae ks 27m 'y RR x CONNECTING Soy Bes WITH RESIDENCE Aa >: @ = 13 ae LEVEL Se EVN ee agra . aoe os = <n ye NN SEN nS FE ELLER Z 2 LE x Ls aS <a = Z Z LILLE IK ee Sy, ON NOE <¥ ya 4 am VN = . \\\ \ wk \ w\ N \ * \ * at TUNNEL GFT. 41N. HIGH 4FT. WIDE AND 200 FT. LONG CONNECTING ES . WITH RESIDENCE WATER PIPES, WIRES UNDER FLOOR

TELESCOPE

v i ELECTRIC AND POWER \)if AMES HARTNESS standing beside the telescope of his unusual under- ground observatory at Springfield, Vt. In the accompanying article he vividly describes the benefits he has derived from his hobby —astronomy from the cellar. The valuation he places on this hobby is remarkable considering his widely diverse achievements. Starting as a machinist’s apprentice at the age of 16, he now is at the head of a machine manufacturing con- cern doing a business of $10,000,000 a year. In addition, he has been governor of his state; he has taken out more than 100 patents; he has served on state, Federal and international commissions; he formerly was president of the American Society of Mechanical Engineers; he is an author and lecturer, and he has been honored for his achievements in the world of invention by universities and scientific societies. And yet, above almost everything else, he prizes his hobby. His advice to every man is to acquire a hobby as a means of supplying a balance for the mind OFFICE UNDER OBSERVATION — = CHAMBB

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— er through astronomy— an accidental hobby with him—he found both happiness and a philosophy that helps to carry him over the rough places. “Astronomy,” he said, ‘‘has given mea better conception of where we are and where we are going. Probably I can make this plain by telling of a little incident that happened _re- cently. “A visitor to my home was telling me of a European trip from which he had just returned. Hav- ing been abroad many times myself, I natur- ally was interested, and offered a few ex- periences from my own travels. I fear both of us became somewhat boastful, as men often do when telling of the strange : places they have visited in their lifetime. ‘My little granddaughter, who was in the room with us, seemed quite unim- pressed by our talk. And at last, as my visitor finished a description of an odd little village in a-remote section of the Alps, she suddenly exclaimed: ““*That’s nothing. Grandfather and I have seen heaven!’ “T could not bring myself to reprove her, because what she said was so close to the truth. We had seen heaven—many times, through my telescope. We had brought the celestial bodies close to us— POPULAR SCIENCE MONTHLY Interior of the remarkable underground observatory, showing ex-Governor Hart- ness seated at his turret telescope. In this cavern chamber the observer is shielded from winter cold and from summer insects, as well as from interruption in his work or rather had approached a little nearer to them. We had seen with our own eyes what an infinitesimal mite of dust is the earth we live on, and how comparatively unimportant in the general scheme of things are the inhabitants of the earth and all their works. “Consider Antares, the biggest star astronomers have measured. Its diameter —the distance across it—is 400,000,000 miles—more than four times the distance between the earth and the sun! Or take Betelgeuse, with a diameter of 242,000,000 miles. Why, if either of those stars were D a * m&: ' DER OR oy mM ttf! 7) ae ie 3S a PASSAGE, — =~ tueentid © e x (NUNN : © STUDY = Senso a> ‘ah e C= —) C3 a , te S = WORK SHOP | Pe OND , i ; - . — > t ; «-«Sifaiiaiaaiaaitasl* At the right: Interior of aE A i the comfortable under- ground study.~ Here Mr. The section draw- Hartness, removed from ing on these two pages the everyday world of shows the complete layout of worry; quietly pursues his the underground observatory, hobby, journeying by tele- »» Tooms, and passages scope to “the vast worlds ire. = 4i to find its way into our solar system, our earth and the other planets would be swept away before it as the wheat stalks fall beneath the reaper! And we of the earth consider our affairs important! “That is what the child meant when she spoke of seeing heav- en; and in the years in which I have pur- sued my astronomical observation hobby, no phrase that I have heard better describes its thrill and its use- fulness. “The bodies in the heavens that we see as mere pinpoints of light, actually are larger and more mag- nificent than our sun; and it is inconceiv- able that on those bodies or on other bodies revolving about them there are not intelligences vastly higher than ours; intelligences that may have solved in part even the mysteries that we on the earth strain to understand as we peer into the beyond through our futile instruments. “That is a conviction that is bound to seize any one who spends some time on astronomy, not from the mathematical standpoint, but as a wholesome, human avocation, a way of stimulating the im- agination. “The units of measurement we employ on the earth—feet, yards, and miles— (Continued.on page 147) I IR OT REG we PRK LOL TTT Wy Pt senna eat te Be 2 / | a1 ‘ oy eee ii if if PRT CLERICAL Yan Mig GE NRE RAST OTE PIE ES OPE Rt RO ESE RI PARR Btn el Pe Yi biconepiiret! mass tbe Doe ERSE Le een A ER oy ee

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42 POPULAR SCIENCE MONTHLY Machine Prints 30,000 Photos Daily Automatic Production of Finished Pictures from Negatives Designed to Give Rapid-Fire Camera Service

HIGH speed pho- / A tographic print- ing machine, which, in point of out- put, bears about the same relation to the ordinary method of printing that the print- ing press does to the pen, has been perfected by a Chicago manufac- turer. Any one who has done photographic work or who has seen contact prints made probably can appreci- ate the amazing capac- ity of a machine that can produce 4000 fin- ished prints in an hour —more than 30,000 in a day. Though designed pri- marily for commercial work, in the rapid-fire production of prints for photographic news services and similar enterprises, this ma- chine, it is said, can be adapted quite readily to the uses of concerns doing de- veloping and printing work for amateurs on a large scale. Combined with a suit- able drying process for negatives, a ma- chine of this sort would make it possible for amateurs to paste their pictures in the album a few hours after they had snapped their cameras. Machine Performs Eight Operations Not only does the machine expose photographic prints at remarkable speed, giving to each the varying intensity and duration of light required, but it develops, rinses,. fixes, and washes them, counts them out and sorts them with absolute accuracy, and prints descriptive matter on the backs. All this is a continuous operation, which resembles in a way the action of a printing press, and in which the negatives, contained in a frame, cor- respond to the type. The sensitized photographic paper is led into contact with the negatives from a huge roll, much as print paper is brought into contact with the type casting in a cylinder press. Automatic printing and developing machines have been in use in motion- picture laboratories for some years, but, the development of a similar machine for still pictures presented many diffi- culties, chief of which was the fact that, unlike the celluloid film of the movies, photographic paper stretches. A series of rollers, however, has been incorporated in the machine to take up all stretch in the paper and hold it taut as it passes. Prints of several negatives, of course, are made-at one time. A lamp house, containing twelve 100-watt lamps, sup- plies the light, which may be adjusted in intensity and is automatically regulated

and wash the prints.

ROLLERS TAKE UP STRETCH iN PAPER ] i hf : i J | eed Pd feet PRET tears hae -— | sly “4 % eal ‘\ Then the paper is led into a hardening bath, rinsed again -under forced spray and auto- matically; wound up, all surplus water being removed by a powerful wringer. The roll of wet paper then is transferred to a drying machine, con- sisting of two gas- heated drums and three silver - plated, gas - heated rollers. The sil- ver plating on the roll- ers produces a_ high gloss finish in the prints. When the roll is dry, it is slit by hand into lengths of four feet, from which the sepa-

The new automatic developing machine, showing the exposed sheet of sensitized print paper passing from a roll in an endless sheet through compartments that develop, fix. The paper moves over rollers that take up most of the stretch GAS-HEATED DRUM SILVER-PLATED H ROLLERS The drying machine. Here the wet paper containing the prints passes over gas-heated drums. After drying, the paper is carried into contact with silver-plated rollers that give the prints their fine glossy surface between one tenth of a second and three - seconds, according to the length of ex- posure required. After printing from the negative, the paper passes into a developing tank, the development being controlled by a bar that raises or lowers the paper as it goes through the bottom roller. From the developer the paper passes to an acid rinsing bath that stops development, after which it is fixed in a hypo bath. Next, six spray washers, operating under high pressure, wash the prints thoroughly. rate prints are cut bya power cutter. The machine is said to have proved efficient and practical in opera- tion, and it is estimated that it can accom- plish more work than 15 men. The high-speed printing operation is conducted in rooms much more brightly illuminated than the ordinary photo- graphic darkrooms. All work is done in a yellow diffused light. Possibly it is well to explain that this machine does not develop negatives— that is, films or plates as they are taken from the camera after exposure. Its pur- pose is solely to make prints from these negatives after they have been developed in the customary way, but a tremendous saving in time over the usual methods of printing is said to be accomplished.

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How the negative is inserted in the print- ing machine. Twelve 100-watt lamps make the exposure on the roll of print paper

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a. eo Rw v | mm | POPULAR SCIENCE MONTHLY Says Dr. Paul Kammerer: The Leopard Can Change His Spots And Fathers Can Pass Their Good Characteristics to Their Sons By Lane Stuart T acquired char- acteristics—the deft fingers of the musi- cian, painter, or skilled arti- san; the ingenuity of the in- ventor, the wisdom of the statesman—can be passed on from father to son is the amazing message _ recently brought to America by Dr. Paul Kammerer, biologist, of the University of Vienna. An Enthusiast I called on him the day after he arrived in this coun- try. I found him confined to his bed in a New York hotel, the victim of a recurring fever contracted on one of his early exploring trips in Africa; but even his sickness could not diminish his enthusiasm once he was on the subject of his life work—the endeavor to prove scientifically that the highest qualities we have built into our lives can be passed on to future genera- tions. Doctor Kammerer has reached his revolutionary conclusions after almost 20 years of scientific experiment with lower animals. He has grown eyes in blind newts. He has given to land toads the physical character- istics and habits of the water- dwelling branch of the species. He has changed the D color of the spots on a sala- mander’s back. Eventually, he says, he hopes to prove that the leopard’s spots can be changed in the same way. Changes Permanent He has caused certain amphi- bians to alter their breeding habits. And these new char- acteristics, produced by’ pa- tient scientific work on suc- cessive generations, he asserts, are made permanent, and are transmitted by their posses- sors to their progeny, on and on. * Darwin; leading universities. branch of life invariably ap- ply to all others—plant life discoveries of medical science are the result of scientific work on the lower animals— guinea pigs, rats, and rabbits. Science derives its principles regarding life from the lower animals, then works gradu- ally to man. Proof from Animals “It is on this method of scientifie research that I base my conclusions. I cannot prove absolutely that the characteristics acquired by one generation of man will be transmitted to the next. Pos- sibly I never shall be able to do so. Man’s span of life is too long for one investigator to observe facts regarding several generations. With the lower animals we can do so because they are short-lived —five or six generations live and die in a decade. My hope, though, is to prove this principle of the transmission of acquired characteristics in the lower animals so con- clusively that science must accept it ag being true of man A Second Darwin? R. PAUL KAMMERER, biologist of the Univer- sity of Vienna, has been a storm center of scientific discussion ever since he first announced his revolutionary doctrine of “‘short cut evolution’’—the theory that a son directly inherits the acquired characteristics of his father. Scientists of world-wide reputation have hailed him as the greatest biologist of his time, the logical successor to others of equal standing have been skeptical, and a few have called him a misguided enthusiast. The attention of the world was focused on Doctor Kammerer when, about a year ago, 50 professors and students at.Cambridge University invited him to England to demonstrate his theories. And now he comes to America to lecture to our The accompanying interview is presented in the belief that whether you agree with Doctor Kammerer or not, you will be interested in his theories. to the same degree. “Long after I was con- vinced by my experiments that it was true, I was grati- fied by a striking corrobora- tion in the findings of Dr. Richard Semon, a German scientist. Doctor Semon dis- covered that a child before birth bore callouses on its feet, near the big toe and, the heel, where its ancestors had developed them through many generations of walking. Seeking More Evidence Callous growths on the feet certainly are an acquired characteristic. This is the only instance I have heard of where the principles I am seeking to prove seem to ap- ply to the human race. One case, of course, is not conclu- sive. But others will come to “These,” he explained to me, “certainly are acquired . characteristics, not natural ones. Take the proteus, or blind newt. This animal for centuries has inhabited the dark cav- erns of the seas. It has had no need for eyes, and its eyes have become mere rudi- mentary organs under its skin. I exposed Successive generations of newts to red light—constantly, night and day—and at last a newt appeared whose eyes had pushed through its skin. Moreover, this characteristic was transmitted to the next generation. “If this transmission of acquired char- acteristics can be effected with some animals, I am convinced that it will apply to man as well. Principles applying to one light; ot that I feel certain. “It is not in the transmis- sion of purely physical characteristics, however, that the human race is chiefly concerned. I hold also that mental, ethical, and moral characteristics, once acquired, can be made inherent. I be- lieve that every deed, every happening not only leaves an indelible imprint on the individual but is transmitted to the and animal life alike. The - re reer se Aaa Wiis ARTS oA ch lad Deana EG . - — — eos initia ae ee Jeliacibilh dad Weide REPIIIEY Fie F863 SE , 4 ¥ fa . ‘ ie wh owt

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eb gn a arnt A ani ne ane OSE Sa een Oye, hey ao kar athe Salpaees peter Mg SEE Ne he 44 offspring. Hence, I believe, too, that favorable characteristics produced in one generation through normal life and wholesome environment can improve the human race and result in marvelous prog- ress from generation to generation. “This is more than eugenics. I may call it eugenics from a positive standpoint, rather than from a negative one. That is to say, instead of seeking to improve the human race by the elimination of bad qualities in succeeding generations, I hold that the improvement should be brought about by inducing positive, good qualities which will be transmitted to the offspring. This, of course, is a matter for the future. I can only hope to point the way. “Science long has recognized that cer- tain animals acquire a color similar to the color of their surroundings. For example, the hair of certaix rats in the deserts is sand-colored. Every one knows of the white-furred animals that inhabit the polar regions. I seek to prove that the acquisition of these colors is due to the animals’ direct imitation of their surroundings. Further, I hope to prove that their bodies are altered in form and struc- ture, and that these changes are not characteristic of the lower animals alone, but of mammals as well, and probably man. Color Changes Inherited “In experiments with sala- manders I have shown that specimens forced to live on a yellow background eventually become almost yellow and that their progeny is yellow at birth. Likewise, salamanders that have lived on a_ black background become almost entirely black, and the next generation is black as well. By plac- ing land toads on an island in a warm aquarium through which cool water was flowing, I caused them to plunge into the water to escape the heat and to acquire, in time, the characteristics of the water- dwelling toads, including pads on the feet. These characteristics have become per- manent and have been transmitted to the next generation. “Strange to say, I have noted that the acquired characteristics become stronger and of greater hereditary power than the original, or natural characteristics. Prob- ably I can make the reason for this clear by a simple analogy. A man is more conscious of new shoes on his feet or a new ring on his finger than of old shoes or an old ring he has been wearing for years. That is because the new articles irritate. New Qualities Gain Force A somewhat similar sort of irritation is caused in animals by a new physical characteristic, because it is unfamiliar. And the acquired characteristic, because it is constantly making its presence evi- dent, exerts a stronger force in propaga- tion than the old characteristics. “Dr. Francis B. Sumner, of California, by placing rats in cold and warm rooms, has caused the animals to vary in the heaviness and texture of their coats. He also has performed experiments that have indicated that color changes in animals POPULAR SCIENCE MONTHLY Salamander confined on black soil, showing growth at one year intervals and pro- nounced ten- dency toward blacker color Salamander confined on yellow _ soil, showing changes at one-year in- tervals and increasingly lighter color Both of the salamanders, the growth of which is pictured above, were descendants of a fire salamander confined on yellow soil during its life come about through evolution- ary changes through many gen- erations. My contention is that the evolution is shorter; that the changed characteristics are ac- quired by one generation and transmitted to the next, after which they are permanent and will remain so until change of environment causes other changes. These two photographs show the results of the remarkable experi- ment in which Doctor Kammerer claims to have grown eyes on a blind newt to prove the inheritance of acquired characteristics. At the left is the eyeless newt that inhabits dark sea depths. right is a newt that has grown eyes after successive generations sub- jected constantly to red light. The eyes have pushed through its head are due in large measure to the animals’ adaptation to their surroundings. That is to say, color changes are due not merely to the survival of those animals that in colorings are best fitted to live in their particular surroundings, but to more or less rapid acquisition by the animals of the color of their surroundings. “These changes—in color, form, struc- ture and traits—biologists generally hold Doctor Kammerer at work in his labora- tory, examining a rat with which he is experimenting to prove his_ theories “It is a long step from my ex- periments to the formulation of principles that may be applied At the to man. I am_ convinced, though, that some day we shall have well-defined laws regarding the transmission of characteris- tics in the human race. We shall know how favorable characteristics may be ac- quired and how they may be passed on. Then the world always will be assured of leaders in the arts and sciences.”’ Doctor Kammerer is a slight man of 48, an ascetic in appearance. He is a musi- cian and composer and the author of a dozen books and innumerable scientific papers; yet his revolutionary theories have met with slight encouragement from the scientists of his native land. When he sought the right to lecture at the University of Vienna 12 years ago, the scientific paper that accompanied his ap- plication was rejected summarily, and the application denied. A little later, though, this same paper was awarded the Soem- mering prize, his country’s most coveted award for distinguished scientific work. Called to English University « Then the University of Vienna sought out Doctor Kammerer, making place for him as lecturer. Yet he had to live, support his laboratory and buy biological speci- mens, on about $150 a year. Then he was called to the colors. After the war, he no longer was able to maintain a laboratory, and the pursuit of his work seemed hopeless until, about a year ago, he-was invited to lecture before a group of scientists at Cambridge Uni- versity, England. There the attention of the world was drawn to him, and his present visit to America is the result.

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he on life ition- ' gen. ; that at the e ac. | and after t and ge of other Ly eXx- on of oplied inced, - shall irding eteris- know be ac- d on. red of of 48, musi- on tific eories , from ure at o, the is ap- id the ough, Soem- veted work. ought ce for pport speci- le was ble to uit of out a pefore | Uni- ontion 1d his ‘to lend themselves to pearl POPULAR SCIENCE MONTHLY Fish Planters to Make Our Rivers in Pearls Yield Fortunes Here is the channel cetfish of the Mississippi, one of our fresh-water fishes upon which young pearl-producing mussels feed and thrive By Robert E. Martin CIENCE soon will place millions of Me dollars in the inland streams of the United States, there to be gathered by any one who desires. This amazing announcement was made recently by the United States Bureau of Fisheries which, through scientific propagation of fresh-water mussels, plans to make dozens of rivers throughout the land yield rich harvests of wealth in pearls. During the last year the streams of the country are estimated to have given up $15,000,000 in these gems, produced by natural means within the shells of mussels that lie along the bottoms of rivers like the Mississippi, and the Black River and White River in Ar- kansas—streams that have been dragged by pearl fishers for years. Science Enriches the Pearl Market But this enormous annual wealth in fresh-water pearls is small, say govern- ment experimenters, compared with what may be expected from scientific methods of increasing pearl production —methods that will be adopted this year as the result of long experiments by the Bureau of Fisheries with 500 varieties of mussels found in the Mississippi Valley. In from four to six years they expect a crop of pearls that will surpas$ in treasure the richest “strikes” made in the gold- fields of California and Alaska. The experiments of the bureau were conducted at its station at Fairview, Ia. Of the 500 varieties of mus- sels tested, 40 were shown culture. Many of these, it was found, could be stimu- lated to the production of larger and finer pearls. The fact that single pearls worth $25,000 already have been produced naturally and taken from the streams of the country, gives some in- dication of what may be ex- pected with scientific prop- agation. The spawn of the mussel is a parasite. It attaches itself to the gills and fins of certain fish, particularly catfish and bass. Unless it can find this lodgment and feed upon the tissues of the fish, it will die. In from nine to 24 days, depending on the species, the mussel is developed suffi- ciently to drop away from the fish and sink to the bed of the river. There, after several years’ growth, the mussel produces its valuable pearls. The plan of the govern- ment is to procure the spawn under favorable Inoculating a fish with embryo mussels. Water containing the embryos is poured into the gills. The inset shows how the young mussels attach themselves to the gills, feeding upon the tissues Government fishermen rescuing fishes that have been stranded in land- locked sloughs along the Mississippi after the spring floods. they are returned to the river, these fishes will be inoculated with embryo mussels so that they may yield a great pearl harvest A microscopic photograph of embryo mussels, future producers of priceless pearls, which Uncle Sam’s scientists are propagating for commercial use conditions and to see that the spawn has its opportunity to thrive by attaching itself to fish. This will be done by inocu- lating fish that are left stranded in shal- low water when rivers recede after spring floods. Salvaging these fishes by plac- ing them back in the rivers is a work carried on exten- sively by the Bureau of Fisheries, millions of fish being rescued by govern- ment men every year. The method of inoculating the stranded fish with mussel spawn will be either to place them in water con- taining the spawn or to pour the spawn-filled water directly into the gills. The Bureau of Fisheries already has spread mussel spawn through 350 miles of the Mississippi between Iowa and Mississippi. It is estimated that the yield of this sowing will be not less than 3,000,000 mussels, many of which in five years or so will contain pearls. The mussels are gathered by drag- ging the bed of the river with blunt hooks. Then they are subjected to heat sufficient to cause the shell to open without ruining the pearls. After the mussels have been inspected for pearls, buttons and other or- naments are made from the shells, or they are ground up to serve as chicken feed and fertilizer. The largest pearls found in United States rivers in- clude one weighing 103 grains, taken from the Black River, Ark., in 1904, and one weighing 68 grains, from the Wisconsin shore of the Mississippi in 1907. These sold respectively for $25,000 ‘ and $15,000. The record catch for a month contained pearls worth $300,000, taken by Wisconsin fishermen. Before 45 SSSA TEA ON SO A RED I: ANE LASTS ARE TOPE HMPA ETE — - , — cae — . , - pasty as nel Ce ee cheat SE TES EA SAAR AN OE CASA Re DRS v ” (ae ae 5 | { i { if iq if pce ot a wpa Ping thee AS ech a Sos tennant meee Se d - r r cuiaapep bigaind canjucimpuniintcss r eee

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' be rf “4 i fi tr Roar Putting Plants to Work on POPULAR SCIENCE MONTHLY the Night Shift Science Speeds By Newton Burke EARS ago, through the development of artificial light, science made possible the 24-hour day in industry. Now, through the same agency, science is putting plants, like human workmen, on the night shift. For scien- tific research has revealed the fact that certain plants may be grown by electric light. Subjected to artificial light after nightfall, these plants are found to be hur- ried to maturity with double their normal speed and to acquire as well a vigor equal to, and possibly greater than that of plants grown under natural conditions. Growth Is Doubled In a six weeks’ experi- ment conducted recently by the Westinghouse Electric and Manufacturing Co., in a greenhouse at Baldwin, N. Y., 12 varieties of flowers and 12 of vegetables were sown. Half of the plants, in addition to being exposed to the sun during the day, were bathed in the light of six 500-watt electric lamps for five hours each night. The other half received only the light and heat of the sun, being shielded from the rays of the lamps by oilcloth curtains. At the end of six weeks, Professor Hugh Findlay, of the Department of Agricul- ture, Columbia University, who was in charge of the demonstration, found that some of the plants that had been kept working night and day were about twice as far advanced in growth as those that had received only the sunlight. These were plants that bear broad leaves—a characteristic enabling them to absorb the extra light in larger proportion than plants with smaller leaves. The experiment has been hailed as a useful, practical discovery that can be applied immediately in commercial greenhouses to make growers more independent of weather vagaries as affecting the light and heat of the sun. Even more astounding are the experiments in scientific plant culture recently undertaken in a plant laboratory established at Yonkers, N. Y. There 30 scien- tific workers actually are manu- facturing every climatic condition that might affect plant growth. There, too, plants are being put on the night shift, but they are iat Up Nature’s Food Factories Left: A cyclamen grown under sunlight and elec. tric light. Right: Ap. other cyclamen, planted at the same time and grown under sunlight Speeding up the growth of plants under the rays of powerful electric lights during recent tests conducted by the Westinghouse Electric and Manufac- turing Co., 72 a greenhouse at Baldwin, Long Island. Julius Heinrichs, veteran florist, who superintended the tests, is shown above measuring the plants being supplied as well with tropical tem- peratures and with humidity as desired. Atmospheric conditions are being manu- factured artificially by injecting into the air of the greenhouses the carbon dioxid that the plants require in larger quantities than nature provides. The ultimate purpose of the Yonkers laboratory, known as the Thompson Institute for Plant Research, is to con- serve and improve the food supply of the world for future generations. The insti- tution has been established by funds pro- By inclosing healthy aster plants in these glass cages, then introducing a different species of insect into each cage, ex- perimenters at the Thompson Institute for Plant Research discovered that the plant disease known as “asters’ yellows” is carried by the brown leaf-hopper, a very tiny insect vided by Colonel William Boyce Thompson, of Yon- kers, noted mining engineer, financier, and _ philanthro- pist. Several years ago Colonel Thompson recog- nized an alarming possibili- ty that the hand of famine might some day be laid on America, the land of plenty. He foresaw that within 25 years at the rate our popu- lation is growing, the farm- lands of the United States, -under present methods of cultivation, will be taxed to their limit of production; in other words, that the yield of the farms will be barely equal to feed the 140,000,000 or 150,000,000 people who will then be in the country. Patriotic Research He determined to do his share to increase the native crops of America so that this country need never be dependent on the rest of the world for food. The result was the establishment of the Thompson Institute, which bears the same relation to the world of plants that the Rockefeller Institute for Medical Re- search bears to mankind. Control of the diseases of plants and improvement in methods of cultivation, comparable with the sanitary measures by which modern science has bettered the living conditions of man and addedto his span of life, have been awaiting the efforts of just such a pathfinder. The Thompson Institute will stand midway between the State and Federal agriculture experiment stations, busied with solutions of immediate practical problems, and the universities and colleges where botany departments are devoted to pure science. Its research work practical end in view of eventually bettering and increasing the food supply of the world. The institute occupies a nine- acre plot, and comprises a quad- rangle of laboratory buildings and extensive greenhouses. One labora- tory building has been completed at a cost of $700,000 and now houses 30 scientific workers. These include not only plant experts, but chemists, microscopists, bacteri- ologists, and specialists in other 2 (Fe ne Be te a RP EQN ON ere ncaennsaeeenaaes od eee | will be conducted always with the . *

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Bat’ Ss Zo Og- ili- ine ity. 25 pu- rm- tes, i to ion; the | the 000 e in » his tive that r be f the osult f the the that Re- and tion, sures 1 the o his Torts jpson 1 the ment ns of , and where voted work h the . ually y food nine- quad- 's and tbora- pleted ~ | now These s, but ucteri- other related branches of scientific research. The laboratory equipment includes the world’s most improved apparatus for plant research. Individual labora- tories are provided for the experimen- ters, each laboratory having electric cur- rent of 110 and 220 volts, vacuum pipes, high and low steam pressure, gas, re- frigeration, and compressed air as standard equipment. «There are dark- rooms for photographie work, refriger- ating chambers, and a microchemistry laboratory. In one of the greenhouses “sunlight” can be maintained at night, as in the Columbia University ex- periment at Baldwin, by swinging a crane that sup- ports a bank of 42 1000- watt electric lamps above the plants. But electricity, although making possible a night shift for plants, sup- plies only a poor imitation of sunlight; for, while the sun gives 37 per cent light and 63 per cent heat, elec- tric light gives only 7 per cent light and 93 per cent heat. The tremendous heat generated by the lights in this greenhouse would be sufficient to bake the plants under cultivation as well as to make it impossible for any one to enter. So the POPULAR SCIENCE MONTHLY & 5 7 ms ss ee TR Wilk a4 47 pathologist at the institute, constructed about 25 glass cages—greenhouses in miniature—in each of which was placed several healthy aster plants. Insects then were introduced into the cages, a different species in each. Soon it was observed that only in the cage con- taining specimens of the brown leaf hopper, a tiny insect not much larger than a mosquito, did the plants de- velop yellows. This determined the car- rier of the disease. The next step will be to find the causative agent, which may or may not be a protozoan—a single cell of animal life that has its first stage of being in the insect carrier. That found, the next problem will be to produce a plant capable of resisting the disease. It is interesting to note that the method used to determine the carrier of asters’ yellows was almost identically the method em- ployed in discovering that yellow fever was trans- mitted by the mosquito. In fact, there is a remarkable similarity between the dis- diseases. Plant research offers un- limited fascinating possibili- ties for food conservation. heat of the lamps is ‘“‘fil- tered” by causing their rays to pass through two glass plates between which is flowing constantly a stream of clear, cool water. Still other greenhouses are provided with roofs of “‘spectrum glass’’—especially colored glass that absorbs the ultra-violet and other rays of the sun detrimental to the growth of plants. Under these roofs plants have been found to develop with double their natural speed. An investigation during the last six months to determine the carrying agent of “‘asters’ yellows,”’ a virus disease that attacks asters, indicates the sort of prac- tical work the institute will carry on. Be- lieving that this disease was transmitted by insects, Dr. L. O. Kunkel, plant The new $700,000 building of the Thompson Institute, nearing com- pletion at Yonkers, N. Y. Heré 30 scientific workers will use the world’s most improved laboratory equipment to study plant diseases and their How the addition of a “‘night shift” with artificial light increases plant growth. The cucumber plant lettered 6-A and the lettuce plant, 7-A, were grown under both artificial light and sunlight, while the cucumber, 6-B, and the lettuce, 7-B, were grown under sunlight only. The upper picture shows Dr. William Crocker, director of the Thompson Institute for Plant Research and one of the foremost botanists in America The loss through plant diseases of a single bushel of wheat from an acre may not seem appalling at first glance; yet if a single bushel is lost from every one of the millions of acres that are under cultivation, a tremendous blow is struck the world’s food supply. Conversely, adding one bushel of wheat to the yield of an acre may not appear to be an accomplishment of enormous im- portance, yet the wheat crop of Canada has been increased 20,000,000 bushels a year by this means. It is toward this end that the energies of the scientists at the Thompson Insti- tute are being employed. The director of the institute is William Crocker, one of America’s foremost botanists, famous as the discoverer of ethylene. Re cure. The inset shows the founder of the institute, Colonel William Boyce Thompson, noted mining engineer, financier, and philanthropist, who is doing a patriotic work in endeavoring to increase America’s food yield eases of plants and human’ cs tk: RT j y a 5M wer eae Fee 7 izpateneny teas + ~ Bese pee a oq ane Sd fee eT . a te eh th A RL NA EINE RNa ne tas tang ‘ve splat eel ees ha fer La ae. | aa aes 5 t~ ars 4 seslScee

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Na 8 2a Sea en 48 POPULAR SCIENCE MONTHLY My Plan for Cheaper Homes W orld-Famous Inventor Offers Novel Method of Building Distinctive “‘Custom-Made”’ Dwellings of Concrete Slabs By Simon Lake EARLY every- body has felt the pressure of the housing shortage that has existed in the United States for several years. At a time when this shortage was most acute, there occurred to me the possibility of developing a new type of dwelling— one that admitted of speedy. construction and less costly materials, yet one that could be erected by a small number of men. From Ships to Houses It may be remembered that during the war con- ke ee (42 | = ‘RB: Architect’s drawing of a distinctive dwelling such as Simon Lake says can be built of concrete slabs by his new process. Stone walls, slate-shingled roofs, ~ and other exterior decora- tions can be produced; he says, by placing a veneer of the desired material on the slabs as they are cast ment recently studied my new method of house- building, indorsed it en- crete was proposed as a substitute for lumber or steel in the construction of ships and that a num- ber of ships were built of this material. I took out some patents for concrete ships having double walls to make them suitable for carrying grain, and it was only natural to apply this con- struction to houses. I built my first ex- perimental house in 1918 and also built a number of test slabs. Out of that experiment has come a new plan for house building based un the use of reinforced concrete slabs made in standard sizes for all parts of the house. These slabs are hollow, so that a layer of air acts as an insulator between the inner and outer surfaces; insuring coolness in summer and warmth in winter. A Practical Concrete House I have now completed what I be- lieve to be an entirely practical method of manufacturing concrete houses of any type, from a small sea- shore bungalow to a skyscraper, ac- cording to any plans that may be drawn, with any sort of exterior finish or decorations that may be specified, with any sort of interior arrangement of rooms; houses that are rainproof, moisture-proof, cold- proof and heatproof, earthquake- proof, and all but indestructible. Moreover, I believe these houses can be built for approximately half the cost for which brick houses could be erected by the usual standard method of construction. Small houses of the bungalow type can be put up like Aladdin’s palace, virtually overnight. This may sound like a flight of slab is said to be equivalent to 2000 bricks. and the slab may be used in construction on the following day after it is cast Casting one of the reinforced concrete slabs for a Lake-constructed house. One fancy, but I assure you it is not. Plans of construction and manufacture have been worked out scientifically. The strength of construction has been tested by muni- cipal experts and has exceeded their re- quirements. Model houses have been built and have withstood a variety of drastic tests. In this connection it may be well to mention here that a scientist investigating earthquake and fireproof construction of houses on behalf of the Japanese govern- Casting requires only a few minutes, thusiastically, and is tak- ing the details of my process back to Tokio with him. The essential differ- ence between the new plan of con- struction I have evolved and my former experiments in the building of ‘“‘one- piece” houses consists in the fact that, while the early houses were ready made, those that I plan to build now may be custom made. That is to say, the pro- spective home owner need not be limited in choice to a fixed number of “ready made” plans, but may have his house built according to his architect’s plans, no matter what the style of architecture or of exterior finish. Homes by the Wholesale IMON LAKE, world-famous inventor of submarine boats, here describes a novel method he has devised of constructing distinctive houses of a wide variety of dimensions and architecture from precast concrete slabs of standardiged sizes. That building methods of the sort are considered quite practicable is shown by the amazing project recently announced by Henry Ford of erecting a whole city of 30,000 cement and wooden houses on a 5000-acre tract near the Ford plant at Dearborn. The homes Mr. Ford purposes building are to be constructed according to a plan perfected some time ago by Thomas A. Edison, which permits 12 different types of cement houses to be molded in the same set of forms. How tremendous a job is the simultaneous construction of 30,000 homes is apparent when we realize that they would be about capable of accommodating the population of such cities as Des Moines, Ia., Albany, N. Y., Paterson, N. J., Reading, Pa., Nor- folk, Va., Salt Lake City, Utah, and Spokane, Wash. The house may beconstructed on the lines of a Dutch Colonial cottage, a modern American mansion, a square city house, or a factory building. It may have stucco walls and a tile roof, brick walls and-a polychrome slate roof or a fieldstone basement with upper floors shingled. It may be painted, it may be treated to give the effect of marble, or it may remain undisguised and unadorned concrete construction. For Decorative Effects The distinctive decorative effects are produced by placing a ‘‘veneer” of the desired material on the surface of the slab when casting. The effect of a heavy roof of slate, for example, is obtained by installing on the slabs slate shingles only a sixteenth of an inch thick. The effects of tile, brick- work, or stone are produced similarly: Once installed, the ‘‘veneer’”’ becomes an integral part of the slab itself. In my plans for building custom a a ae a a ae aL ee ee a is co cer tt Be ee Ck [ee eee

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Wa ied se- on- ak- my kio on- ner ne- at, de, ro- ted dy use ins, ure the YB are It of, ate rith be the ain ete cts er”’ ace ect dle, abs ck- ‘ly. nes om made houses I am making use of the well known manufacturing principle of stan- dardized parts. The units of construction are slabs 12, 16, 20, or 24 feet in length and up to 10 feet in width. Those lengths are used because I have found them con- venient and best adapted to the various types of houses. The 10-foot width was adopted because that is the maximum width of slab that may be transported safely on a flat car. The slabs are to be cast in a central plant, carried to the location of the pro- _ posed buildings, and lifted into place by derricks. One wall slab, of the 10-by-20- foot size, which can be cast in a few min- utes, is equivalent to 2000 bricks. Since the “setting” of the concrete can be speeded by a special process I have de- veloped of circulating warm air through its hollow interior, the slabs can be in- stalled on the second day following their casting. That this method of construction should POPULAR SCIENCE MONTHLY be cheaper in labor cost to the unit of area than the build- ing processes com- monly employed is apparent. A further saving in this par- ticular is effected by the use of derricks to lift the units in place. Since by using the slabs we start with a saving of at least 50 per cent on materials, I feel confident that the efficient application of my process can result in a 50 per cent cut in the This drawing shows how the inventor foresees the application of his method of constructing ‘‘custom-made”’ slab houses to large-scale subur- ban development. The slabs would be transported to the development site by railway, lighter, or motor truck and carried to each house site by a traveling derrick running on tracks. In building a house the derrick also would lift the slabs into place. All excavation would be done by mechanical shovels, as shown. At the left: Testing carrying strength of the walls of a small house constructed by the Lake process. The weight on the roof is 31,000 pounds, equivalent to 765 pounds a linear foot 49 against moisture and air leakage. These units also might be utilized on a steel skeleton in the construction of sky- scrapers. Several test houses constructed entirely on these plans have withstood shocks and jars when being transported from place to place by motor truck, greater by far than the strain put on any structure in Japan in the recent earthquake. I have estimated that for $3500 it will be possible to build a seven-roomed home of the type that has recently come into great popularity in sub- cost of a house. Except for purely decorative features in- side or out, the houses I have planned would be of slab units through- out from foundation to roof. Wooden or other flooring, if desired for decorative effect, would be laid over the con- crete floor slabs. The units would be joined by a patented method, which would make the completed structure virtually one _ piece, effectually sealing it Demonstrating built house is that the Lake- earthquake-proof. The truck carrying the house has slipped into a deep rut, subjecting the building to a strain that the in- ventor says is greater than that ex- erted on any structure in the Japan- ese quake. The house was unharmed urban developments. This is much less than a good quality frame house of the same sort would cost almost any- where in the United States. And not only will the new process enable the home-builder to obtain a house at half the cost of other type dwellings, but also it will save him practically all cost of upkeep and repairs, assuring him of a home that should stand for many generations, cise.

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jaa et Dern s cement Sterne So aetrh tent eahete te fore ke SONS EAE. LE SEER Ea eee RS ee nS ince at eS e Sih ame = Uy POPULAR SCIENCE MONTHLY A MOVING SCAFFOLD FOR PLASTERERS HE sight of four plasterers suspending their work for an expensive period while they moved their staging, gave toa foreman for the Aberthaw Construction Co., Boston, Mass., an idea for the elimi- nation of this waste in transportation. On two sets of light wheels, taken from concrete buggies, he mounted a working platform, as shown above. The plasterers move this rolling platform from place to place by pushing against the wall with their hands. Combination Bed and Easy Chair OMBINING the functions of easy chair and bed, a newly invented fold- ing armchair with an ingenious. ar- rangement of fit- tings and compart- ments under the seat is designed especially for use in the small modern apartment, or for invalids. By pressing a lever, the occupant can adjust his position to any desired angle. A bookrack, writing-table, and medicine ‘chest keep all the more necessary com- forts within easy reach. The two front legs of the chair slide forward. How the folding chair is converted into lounging chair and bed. Pressure on a lever adjusts the back’ to any de- sired angle. Note the handy com- partment beneath SNOW MACHINE LOADS AS IT SHOVELS OUNTED on | a track-lay- ing tractor, this powerful snow loader, perfected at Aurora, IIl., is de- signed to remove snow quickly from -city streets. The manufacturers claim it will load a five-ton truck with eight cubic yards of snow in 2% minutes. While a powerful shovel plunges into the drifts, the endless belt conveyor car- ries the snow up- The tractor conveyor loading snow into a truck as it is shoveled ward to the truck. conveyor and © Midget Washing Machine Weighs only 30 Pounds A MIDGET electric washing machine that can be stored in a bureau drawer between washdays has been in- vented for apartment dwellers and others who find the standard sized machine too large. It is cylindrical, six inches in diameter and 22 inches long. With the elec- tric motor, which fits in the top, it is said to weigh only 38:0 pounds. The ma- chine is placed in a corner of a tub, wash boiler, bath- co ae a tub or sink : A holes thr hich filled with hot — water and the soiled clothing. A four-bladed centrifugal pump in the lower part of the cylinder, into which water flows through small holes, ejects a vigorous current that swirls the clothes, cleaning them. This current has a jet pressure of five pounds to the square inch. It is claimed that 10 . minutes’ operation suffices to clean a tubful of clothes. Spring Churns the Butter with Little Urging USPENDED from a 12-inch spring, this ingenious self-operating churn is said to turn out a batch of butter in five minutes. The cylindrical container, held between two wooden strips by long thumbscrews, is hooked to the spring which, in turn, is attached to a rope tied to a convenient beam. Once set in mo- tion, the churn needs little urging. The churn and its ingenious spring suspension ee em oS eo THK TO fit eal an. — 2 Pp ae ze, ot cot tes ct te _ fer) ao =o Jd ct

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al Yr, all is 10 . ‘to an upright Socket Holder Converts Vase into Lamp RNAMENTAL vases may be con- verted instantly into attractive elec- tric lamps by the insertion of this newly invented socket attachment. Within wide limits, the fixture will fit any size vase. Should the receptacle be desired for flowers, the attachment may be with- drawn. Trophy cups can become dis- tinctive utilities. Two spring clips press the inner walls of the vase so firmly that the vase-lamp Inserting the socket attachment in vase may be picked up by the top. No boring and no weighting with sand are necessary. The cylinder shown between the two clips is a two-pound weight that brings the center of gravity beneath the mouth of the vase, stabilizing the lamp. Safety Stand for Smokers Won’t ne Ashes ERE’S a smoker’s stand that can’t fall over or spill ashes, and that extinguishes lighted matches and stubs dropped into it. The weighted base causes the stand to return position when tipped. Any- thing dropped in the ash re- ceiver falls into the hollow base, where lack of oxygen extinguishes tobacco embers and burning matches. It is claimed also that the base retains all stale tobacco fumes. POPULAR SCIENCE MONTHLY 51 The huge swimming pool nearing completion World’s Largest Swimming Pool 1000 Feet Long AN $80,000 swimming pool, said to be the largest in the world, has been completed in a 60-acre park at San Fran- cisco in the hope that it will serve as an attraction to bring the Olympic games to America. Measurements of the great tank are standardized for official aquatic contests. It is 1000 feet long and 100 feet wide, with the exception of a central portion 50 yards wide to provide for a racing course across the pool. At one end is a diving pit 14 feet deep. The rest of the pool ranges in depth from three to nine feet. A 16-inch steel pipe line will bring 5000 gallons of water a minute from the we Calking seams in the concrete floor Pacific Ocean, thus keeping in constant circulation the 6,300,000 gallons in the pool, which will be emptied by gravity. The concrete floor is formed in sections, with one-inch seams between each section, permitting the concrete to expand without cracking. To prevent the salt water from leaking through them, the seams are calked with oakum and poured with plastic asphaltic cement. This Strong Box Sounds Burglar Alarm — burglar who lifts this steel strong box will be surprised. Immediately a loud electric bell will start clanging and the racket won’t stop even if the box is replaced in its original position. A lever inside is thrown to set the alarm. A metal pin, capable of oscillation, projects from the bottom of the box, as shown in the illustration. When the alarm is set and the box is resting on a table or in a drawer, this pin presses against the supporting surface. The slightest disturbance of the box causes PAPER COVER sinsanile AU the pin to close an electric circuit that actuates the bell alarm, which rings until the spring is unwound. O PROTECT motor cars stored for the win- ter, shielding them from the fine dirt and dust that in- jure the finish, this easily adjusted cover of strong, heavy paper has been introduced by a manufacturing concern in Shelby- ville, Ind. The covers are made in various sizes to fit standard cars, and are designed oa Zz a to serve both the individual owner * or the dealer. This paper auto cover can be folded into a small, compact bundle PEN tre ae er re ee ere eee ys ; . oe

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52 PANTOGRAPH ARMS ae ene fips ait eee AREA Secu. Shiite Sgt Oey as au anor tioae rael RECISE measurement of the human heart is said to have been made pos- sible by this X-ray pantograph apparatus in use at the British National Hospital for Diseases of the Heart. It is called the “orthodiagraph.” POPULAR SCIENCE MONTHLY MACHINE DRAWS DIAGRAM OF HEART, ACTUAL SIZE HUMAN HEART MEASURED BY X-RAYS As the X-rays reveal to the operator the outline of the heart through an obser- vation disk, he traces the outline with an indicator. To the indicator is attached the arm of a pantograph, which draws a diagram of the heart, actual size. Portable Swing Lifts and Moves Patients Fey Aline may be moved in comfort by this simple device. A canvas seat is placed beneath the patient, who is raised in a sitting position on the bed. Attached to the ends of the seat are two sprocket chains running through support- ing arms to sprockets turned by a hand crank. By turning the crank, the atten- dant lifts the patient from the bed. The apparatus moves on casters. > = = == = ROR ELS Ps fist sont 5 he oad Turning a crank lifts the patient Tension Wheels Cut from Solid Steel Disks A NEW type of tension wheel for auto- mobiles, smart in appearance and said to possess advantages over the com- mon wire wheel, is popular in Europe. The wheel of lattice construction is made of two members stamped from solid disks of an especially light steel. Thus, tightening of individual nipples to adjust the tension of spokes is obviated. Since the wheel is made of two stamped disks, the tension naturally is distributed evenly. It is claimed that because of the special steel construction, it is stronger, lighter, and more resilient than other types. WATER-GLASS, mixed with boiling water to the consistency of syrup, can be used effectively as a cleanser for clothes, dis- colored dishes, marble, or enamel ware. ‘shanks of jaw This Handy Tool Sharpens Razors or Knives ; SIMPLE. implement for sharpening razors and knives, devised by Rockwell A. Loomis, of Guatemala, consists of a tubular handle with a threaded socket in which are inserted the members. Each jaw holds a sharpening stone. ! The blade of the knife or razor is in- serted in a V-shaped opening between the jaws and drawn across the stones. The abrasive stones are detachably mounted so that coarse or fine stones may be used. Useful Garage Truck ‘Tas handy truck, built low so heavy objects need little lifting, and fitted with rugged ball-bearing wheels, is designed to save time and muscle in the auto- repair shop, Moving an auto engine Grocer Candles a Dozen Eggs at a Time ““NANDLING,” the process by which light is made to reveal the devasta- tion wrought by an egg’s age, recently was made conveniently available to his house- wife patrons by an enterprising grocer. His device, an observation chamber built of old boxes and containing an elec- tric light, bares all egg secrets. Testing a dozen eggs at once

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18 an unusual type of “runabout” electric crane recently has been in- troduced into British factories and engi- neering works. It derricks, hoists, and travels under its own power, and it can penetrate into any corner of a manufac- turing plant inaccessible to a fixed crane installation. The machine might be compared with a giant hand, ever ready to do heavy work, such as lifting a heavy casting on to a lathe, or taking steel forgings from a fur- nace to the machine. Be: on an entirely new principle, Crane Carries Own Power Unit Cranes usually used for such purposes have long wheel bases, and consequently are clumsy and difficult to handle. These difficulties have been overcome in the new crane by combining lifting gear and chassis in a compact unit. The crane is supported by four pairs of wheels. The front and back wheels serve for steering, while two pairs of side wheels are for turn- ing the crane. These side wheels do not swivel. They are driven by electric motors suspended from the chassis, acting through a reduction gear. When turning, the motors are con- nected in such a manner that they turn in opposite directions; so that the crane turns on the spot about its own axis. For turning, the front and rear wheels are placed at right angles to the side wheels. The hoisting and derricking operations are accomplished by a single motor driv- POPULAR SCIENCE MONTHLY This traveling crane can penetrate into factory corners inaccessible to a fixed crane ing rope barrels through spur-and-worm gearing. A new brake mechanism is fitted to the clutches through which the lifting gear is driven. When the clutch is being withdrawn, the brake is applied gradually from the start, and vice versa when clutch- BA of the 12 important scientific facts embodied in the answers to the questions asked below may come in handy for you some day. You may be the only one in a group to know one or more of them, when the questions are raised. A sure and ready answer will bring you the respect always accorded the man who knows, the man who understands the principles that un- derlie and animate the world about him. Or you may have occasion to put some of them to highly practical use. Under- standing the principle of the fireless fireless cooker? music? closer? Sa times? — HOW MUCH SCIENCE DO YOU KNOW? 1. What is the difference between coal and diamonds? 2. Why does the bleeding from a cut soon stop? 3. Why does food continue to cook after being placed in a 4. Can the songs of birds be written down as we write other 5. Why is it cooler on a mountain top, though the sun is Is it true that a drowning person always comes up three 7. What is the safest stimulant? 8. What is the speed of thought? 9. Why is the water of the sea salty? 10. How can you make air hot without applying heat to it? 11. How does the phonograph reproduce sound? 12. How do fireflies produce their light? cooker, for example, might enable you to improvise one on a camping trip. These “Monthly Dozens’”’ that appear in each issue of POPULAR SCIENCE MONTHLY are an easy and fascinating course in science, a course with the zest of a game. Test your knowledge of science with these questions. When you’ve done your best, turn to page 150 for the correct answers. _ You'll be surprised at the amount of real satisfaction and practical value you will gain from this knowledge of the sim- ple facts of science. ingin. This is said to save a great deal of current. In addition, the motor is auto- matically stopped or started when the clutch lever is operated. Current is supplied by a storage bat- tery that also acts as a balance weight. Smoker’s Reading Lamp Has Ashtray Attached OR the man who likes to smoke while he reads, this combination ash re- ceiver, cigar rest, and match receptacle is attached to the base of a portable read- ing lamp that will clamp on a table edge, a chair arm, or almost any convenient rest. The device also is adapted for ecard playing, for the lamp when clamped re- quires only a few inches of table surface and the ashtray is below the table level. RL oP a ne ‘ Lamp and ashtray attached to table

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Pedder gag a abe KIER. baaen bey, eid BSeRY HEE AS aN AT ae ESE bites Ted biShie-e ncaemingeticae SUES POPULAR SCIENCE MONTHLY Harvester Tops, Digs, and Loads Vegetables OPPING, digging, and loading beets economically and rapidly, this in- genious farming machine, invented by Joseph Wolny of Sheridan, Wyo., is said to do work that formerly required the labor of from 20 to 25 men. Its per- formances promise a wide utility in the great sugar-beet fields of the United States. The machine is said to be effective also in handling other root vegetables, such as carrots and turnips. Four revolving knives and one sta- tionary knife, the latter fastened into two flowing guides, constitute the topping mechanism that is adjustable to any height. A plowlike arrangement digs Rear view of the vegetable harvester, showing - how beets are dumped from loaded container the beets and a conveyor carries them toa box at the rear. When this box is full, the operator pushes a lever and the con- tents are dumped in a pile. Mechanical Servant Cuts and Cores Oranges UTTING and coring oranges or grapefruit quickly and attractively, this light, handy new machine is designed especially for the housewife who takes pride in equipping her kitchen with time- and labor-saving mechanical servants. It is claimed to work with five times the speed of hands. A pair of curved blades is arranged ingeniously to give an up and down as well as a circular motion. The fruit is held just beneath the blades in a cup that forces it upward. The machine may be clamped easily to the edge of a table. Smallest Motor-Driven Woodworking Lathe A NEW single-speed bench lathe, said to be the smallest woodworking lathe with motor-driven headstock, is being manufactured for the smaller turning operations that make up the bulk of the work in nearly all woodwork- ing shops. The lathe is intended for work up to six inches in diameter and operates at 3400 revolutions a minute. It weighs but 203 pounds and can be moved with fair ease. It is 46 inches high and 40 inches long. The sub-base is open, serv- ing as a holder for tools. An entirely inclosed one-third-horsepower motor drives it. The midget lathe, showing headstock motor This Handy Tool Combines Wrench and Pliers (\OMBIN- ING a pair of pliers with a monkey wrench that can be ad- justed instantly without turning the usual knurled wheel, this unique tool has been de- signed espe- cially for home use. When . used. . as a wrench, the jaws are ad- justed to the object they are to clamp and the toothed tip of the pliers handle is en- gaged in one of the depressions of the corrugated strip beneath the lower jaw. This holds the jaws firmly in place. Desk ‘‘Ferris Wheel’’ Holds Pencils, Pens, and Ink oes as a compact and handy container for office materials, the | Ferris wheel device shown above has been designed to save time and annoyance for the business man. Extending between the two wheels are four bars, each suspending two ink bottles in two holders. Two troughs, one on each of two other bars, hold pens and pencils. These, like the Ferris wheel cars, cannot tip. At the base of the device are six covered cups that serve as containers for pen points, pins, paper clips, and similar small articles. A drawer seven inehes wide, two inches deep, and 15 inches long receives papers. The wheel is so balanced that it will remain stationary in whatever posi- tion it is placed. ‘*Tin Hats’’ Worn by Miners RMY “tin hats,” designed to turn shrapnel in battles of the World War, are now being used as head protection against rock and ore in mines of Califor- nia, West Virginia, and Oklahoma.

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ers turn W ar, stion lifor- A Rapid Envelope Sealer for Office Use i te small but efficient envelope sealer is designed for use in offices where a more expensive device is not ad- visable. It is but a trifie larger than a fountain pen. The handle contains enough water for sealing 1000 envelopes. Attached to the handle is a pan containing a felt pad that moistens the glue on the envelope flap as the sealer is drawn along it. A presser _foot, immediately behind the pad pan, presses down and seals the flap. It is claimed that 60 envelopes a minute can be sealed with the device. Guard Attachment Aids in Spraying Paint PROTECTION of machinery, stock, windows, and other surroundings while adjacent surfaces are being sprayed with calcimine, whitewash or similar paints, is said to be possible through the use of a newly perfected guard attach- ment for the paint sprayer. This guard, it is claimed, makes the spraying machine a superior tool for painting walls and flat surfaces, or for oiling large floor spaces. The swing joint and nozzle work inde- pendently of the guard, and the nozzle may be focused at any angle. This per- mits of spraying trees and shrubbery. The paint spray with guard attachment ER ERO EE BR TOS _ POPULAR SCIENCE MONTHLY MOVE TOWN TO BUILD A RESERVOIR HE entire town of Ameri- can Falls, on the Snake River, Idaho, is to be moved by United States government engineers in the course of building what is to be the largest reservoir in the country; for the projected stor- age basin will cover deeply the present site of the town. Eighty-three thousand acres surrounding the town are to be inundated when the project is completed. ae oS Ce Tee mre oe “eS - = "o_o | na? coal ' ie Above: View of the Snake River, near American Falls, Idaho, which will supply water for the huge reservoir. At the left: Part of the town of Ameri- can Falls which will be moved to make way for the government pro= ject. When the reservoir is com- pleted, 83,000 acres will be inundated This gigantic reservoir will have a capacity of 1,500,000 acre-feet of water, and will involve an expenditure at present estimated at more than $12,000,000. Chemical Drawings Made Easy by Templet O AID scientists, students, and draftsmen to produce neater and more accurate drawings in which chemical apparatus appears, this novel celluloid templet or drawing guide has been de- vised. The figures are punched through. Using this templet, one inexperienced man can make a hundred diagrams while an artist working freehand is completing one or two. Typewriter Records Voice MPROVING on the dictation phono- graph commonly used in_ business offices, Martin Bandli, a Swiss inventor, claims to have perfected a machine that will typewrite dirert from the spoken word, thus doing away with the necessity of first dictating to a phonograph and then passing the record on to a typist for transcription. A speed of from 90 to 100 words a minute—about as fast as the average man can !dictate—is claimed for the new ma-, chine, which is operated electrically. Mechanical Page Turner for Armless Readers = difficulties experienced by armless persons in turning the leaves of books or magazines and in holding down the pages have been overcome to a large ex- tent by a simple mechanical finger with a rubber tip. Holding one end of the device between his teeth, the armless reader manipulates it so that the tip gains purchase at one corner of the page. When used to hold the page, the instrument rests on the tip and the two legs. Turning a page with rubber-tipped finger a Mot oe i eth { if ER Wit «i hk i ° | # ; isdegeclheeeat lad snc te eR Ra asi mat ceca igiagt rw

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POPULAR SCIENCE MONTHLY Mow to Kill Your Radio Troubles And Silence the Howling Demons of Noise By Jack Binns America’s Foremost Writer on Radio LICKETY-CLACK, Rat-tat-tat- C tat, bing, bang, E-e-e-e-yow-e-e, crack! This is not a sample of the new type of jazz orchestra, but merely a weak imitation of what a radio receiver can do when it rears up on its hind legs and ‘“‘tells the world.” There are two types of troubles that can be experienced with a receiver that . is not working properly. The first is the presence of a whole orchestra of noise demons. The second is the total ab- sence of sounds or noises of improper value of the grid leak. The remedy is to try grid leaks of different values till the right one is obtained. A steady humming noise usually is caused by near-by power lines or lighting circuits near the aerial or lead-in wire. The remedy is to erect your aerial as far as possible from such lines and as nearly as possible at right angles to them. A loose connection or open circuit in the grid circuit of the detector stage often will © cause a sharp drumming noise that can be eliminated by checking up the grid circuit connections. Whistling or howling noises may be due any kind. SSS x > —z —* == Fig. 5. To assure good con- With the possible exception | - " tact springs of the tube socket of the demon static, there is | Every Noise Has a Meaning \ and tube prongs, bend up the no reason why a properly || ong 8 Gown shove Ralls caielies. haahl wnt IS chart will help you locate your radio t function properly without \ troubles, if you use the noises you hear as a \ F noise or trouble, giving clear, guide. Tack it up for handy reference, pene 4 eyo| pose is 2 distortionless signals from e method use y some ) stations within its receiving NOISE TROUBLE ‘) makers of variocouplers or’ Le range. Crackling Static, run-down batteries, poor variometers to lead out the i wiring connections, or defective connections from the rotor x The Commonest Troubles rheostats and condensers. \\ windings. a Whistling, Too much regeneration, too A lead from the rotor wind- f What, then, are the exact howling many turns in tickler coil wind- ing never should be soldered 4 causes of the varieties of ing, - poorly designed trans- \\ or otherwise fastened to the : trouble that bring grief to formers, transformers too close shaft of the rotor. Flexible : almost every radio fan at together, oe we Bae: 4 = wires should be connected ie some stage of the game? First, - capacity, overloading of tu \\ - with the ends of the windings ‘ M let’s see if we can’t put our Sharp Loose connection or open circuit and the free ends connected - &: fingers on the most common Drumming in the grid circuit of the de- with the outside binding posts Pi of the trouble-makers, de- tector stage. or connections. Where a hol- i termine their locations, and Machine-gun beat Incorrect value of the grid leak. low tube is used as the shaft, : expose the secrets of their Steady humming _—_ Usually caused by near-by power these flexible wires can be noise-making. Afterward, - \\ lines or lighting circuits near the run from the inside of the - Dy Fee we'll discuss the means of guarding against them in de- signing and constructing our receivers. All trouble usually can be traced to defective No noise at all aerial or lead-in wire. Poor aerial or ground. rotor, through the hole in the tube, and out through the end of the tube to the binding posts or outside connections. » = go SSeS 2 ~~ _ ee ~— ion ee *~ parts, poor construction, or unskilful operation. If you get crackling to too much regenera- tion, too many turns in the tickler-coil winding, poorly designed trans- A whistling noise changing in pitch without any adjustment of the receiver is caused by a neighbor tuning in his single-circuit regenera tive set, with the circuit in an oscillating condition. The noises, the first thing to formers, location of only remedy is to find out who operates do is to determine yg transformers too close to the troublesome set and convince him that whether they are caused = yo. TMETER each other, improper _ he should use a double-circuit set or tune by static or by the set. OR LAMP routing of wires so that in his present set with the tube filament This can be done easily grid and plate wires run turned down as low as possible. by listening in with aerial ea closely parallel to each and ground disconnected. e— other, body capacity: ef- When You Hear No Sounds If that eliminates or FIG.2 AERIAL INSULATOR fects when the hand is " cuts down the crackling noises; the trouble is due to static. If the noise pérsists with aerial and ground disconnected, you may absolve the static imp from all blame. Many of the irregular crackling noises in a re- ceiver are duetorun-down batteries, poor wiring con- nections, and defective rheostats and condensers. FIG.4 Fig. 1. How to test for open circuit between aerial and lead-in Fig. 2. Test for short circuit brought near the con: — * trols, neglect to use a fixed condenser across the primary windinz of . the first. stage . trans-. former, and overloading of tubes. The remedy for most of these troubles is ob- vious. Capacity effects practically can be elim- inated by making sure that the rotary plates of Don’t let noises discourage you. The fan who gets noises at least gets some- thing, even though it is unwelcome. He is better off than the fan who expectantly turns on the juice, plugs in the phones, and hears—nothing. One of the most common vauses of “no noise at all” is a poor aerial or ground. Be sure before you make any changes in your set that the trouble is not due to this cause. You can do so by making the tests illustrated in Figs. 1, 2, and 3, using the test circuit shown in Fig. 4. A steady, regular, between aerial and aerial sup- tuning condensers are A voltmeter with graduations reading staccato beat note, some- ; port wires hey connected with the _ up to 30 or 35 volts will be found suitable what like the steady Fig. 3. Test for open circuit grounded or batterysides for all purposes in testing. In connecting patter of a machine-gun, often can be traced to an in strap lead-in Fig. 4. Voltmeter and battery test circuit, with testing points of the circuits in which they are used. Another the voltmeter in the circuit, make sure the positive pole of the meter is connected

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POPULAR SCIENCE MONTHLY — — = | he | de A VS we Wy WY we . or Ww oT @ Ww We Re hy us ™ SS & WN OP 2 SS Ww YW aOR OM pon _ (Ge % \- i a - r or i ial sapiailiimenbaaniniaicaliaa™ ccdtintiieileadaaicaaaaatiteT muiiatisbicinatadiienintiliie Pot a shade : ARTS AI Ce = — sai Ny --- PSASNO RE SCTE: The Radio Imps’ll Get You if You Don’t Watch Out ERE are the noise imps of radio—the whole orchestra of howling, squealing, whistling, crackling, pounding demons that play havoc with radio reception, spoil the fun, and ruin your temper unless you can track them to their lair and silence them. Greatest bugaboo of them all is static, the un- conquered, who grinds his crackler in your ears while he laughs in your face. The home.of the whistlers, squealers, and howlers is to be found in tuning elements and transformers of poor design, in faulty wiring or unskilful operation. Other cracklers usually are found hiding in run- down batteries, poor wiring connections, defective rheostats and condensers, or in dust between con- denser plates. The machine-gunners of the crew have their head- quarters in the incorrect grid leak, while the anvil chorus of the blacksmiths comes from dust in the condensers and from weak batteries. Fase ae a ee em See al eg iret = MDa: 2K BE »é 35 x ea eee ay ~S ee 9 2 sina nes * ir hee ws er ri oS i pee ete Fed iepaiore eianes eons ries Yeo a een ay ir rs . “ : “ — a = seas ee eg - 5 , vc 7 - “ " ~ a my aoe i DR a Paes Fee w _— See Se eo Ajai o 2 = ‘a eh hedge ahi ewes ayo ag en ee ue SS ae ee Oe * Se ee arn ean: ae RIE Re une 2 alee: ‘ ¥ = can fy hie eee aad ee A a p Seise RRS. ancl teBaim ete a Gianioasigiat maaliie asap) sa aaa Mad tat oe rN GP IR ett BAAR TE Ee ie |

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{ ny i S fa j Ee Bae pte Maa > wy L POSER Shaw ad oy i aes ODN en ap 58 with the positive pole of the battery by touching the free end of the meter with the negative terminal of the battery. If you get a reading, the meter is connected properly. If you do not, reverse the con- nections to the meter so that you get a reading when the free end of the meter is connected with the negative of the bat- tery. Testing for Ground Connection To insure a good ground connection, you can make a temporary connection to another ground and then insert your test circuit between your regular ground and the temporary ground. If you get a read- ing, the ground connection is all right. Another way is to test around the ground clamp and see that the ground wire is making a good contact through the clamp with the ground. Many fans, especially beginners, often forget to connect aerial and ground when testing. A common source of trouble is poor contact of tube prongs with socket springs. Before connecting the sockets with the set, the springs should be bent up as shown in Fig. 5. A wise precaution is to bend up these springs every so often and clean off the ends of the tube prongs with a fine file; so that they will make a good contact with the springs. Another source of trouble in tube sockets is loose binding-post connections with contact springs. Screws and binding posts always should be tightened before the socket is connected with the circuit. So much for those who are experiencing difficulty with receivers already con- structed. Forestall Trouble Later On In radio an ounce of prevention is worth more than a pound of cure. Test- ing the parts before connecting them may take time, but it will save you more time, temper, and embarrassment later on. A few simple tests often will prevent any possibility of trouble after the set is built and ready to operate. First of all, test your batteries. This can be done easily in the manner illus- trated in Fig. 4, by touching the two test points together. If a 2214-volt B battery gives a reading of less than 15 volts, throw it away and get a new one. Coils can be tested by connecting one end of the coil with one test point of the test circuit, as shown in Fig. 4, and the other end of the coil with the other test point of the circuit. The volt- meter should show a steady reading. Where the coils of transformers are being tested, a lower reading will be obtained because of the resistance of the coil. The important thing, however, is a steady reading. All coils of variocouplers, variometers, and transformers should be tested in the manner described above and as shown in Fig. 6. Each coil of every trans- former should be tested sepa- rately. The primary-coil ter- minals usually are marked P and B, and the secondary-coil ter- POPULAR SCIENCE MONTHLY whether there is any connection between the two coils, is to touch one test point to one terminal of the primary coil and the other test point to one terminal of the secondary coil. To make sure that the windings are not connected with the core of the transformer, one test point should Fig. 6. How totest the transformer for open circuits, by using the voltmeter and battery be touched to the core or case of the trans- former and the other test point touched first on one terminal of the primary, then on a terminal of the secondary. No read- ings should be obtained during this test. The binding posts and screws of rheo- stats and other parts should be tightened Fig. 7. Before connecting the rheostat with the circuit, tighten all connections as shown up carefully before being used in the cir- cuit. Neglect of this precaution often is the cause of troubles impossible to locate later on. Condensers should be tested as shown in Fig. 8, one test point being connected with one terminal of the condenser and the other test point with the other con- denser terminal. While the test circuit is connected, the rotary plates should be re- volved. During this operation, the needle should not falter. If it does, it indicates that at some point the rotary plates are touching stationary plates or that dust is short-circuiting the plates. If the short circuit is caused by dust, the spaces be- tween the plates should be cleaned by blowing through them; if by touching plates, the rotary plates should be straightened carefully. Rubbing contacts, either in vario- coupler, variometers, or variable con- densers, should not be relied upon. The best method is to connect the leads, ter- minals, or parts with soldered flexible connections. Provide Stops for Rotors Stops should be provided to prevent rotors of variocouplers and variometers and rotary plates of condensers from being turned through more than one revolution. If this is not done, the leads will be twisted or broken, or the insulation worn off, causing short circuits. Fixed condensers, especially the grid condenser, should be tested to make sure that there are no short-circuited condens- ers. When the condensers are connected between the test points, the voltmeter should show no reading. Jacks contribute a large portion of the troubles in amplifier stages. In double- circuit jacks, poor contact of the inner springs with the outer springs often are the cause of no signals or, at best, weak signals in the amplifier stages. Make sure before you connect the jacks that they are free from this fault. Testing Circuits for Opens After you have connected the set, test the various circuits for opens before con- necting the batteries. In the plate circuit, for instance, touch one test point to the plate terminal of the socket, and the other test point to the positive B battery con- nection, to make sure that there is a com- plete circuit between those points. The same should be done with other parts of the cireuit. Before you jump to the conclusion that something is wrong with your set, try vari- ous values of B and C battery voltage, since the correct values are important if distortion is to be eliminated. If you don’t get results after making tests and checking up your wiring, you will find it an actual saving in time and temper to take the whole works - apart and make the tests on the apparatus as I have described them. Don’t try to make all the tests, wire up the receiver, and get good results alin one evening. It simply can’t be done. NFAT month Jack Binns will tell of the most recent progress in the development of secret radio and of the possi- bilities of private wireless communication. Don’t minals are marked G and F. Another test, to determine Fig. 8. This illustration shows the method of testing the condenser for short circuits, using voltmeter and battery miss this timely articleon the discoveries of the day.

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e VS Ww Cr ~- @ 1e er re ak re ost yn- ‘it, she 1er ni- m- ‘he of hat ari- ge, t if ing you and rks the bed sts, get ing. ck the in sret ssiI- less on’t 20n jay. POPULAR SCIENCE MONTHLY 59 Evolution of an Eg¢ in the Movies By Charles F. Herm Formerly of the American Museum of Natural History, Inventor of the Motion- Picture Camera to Photo- graph Embryo Life HE untiring eye of science is the motion- picture camera. The human eye has its limit of endurance. That means, of ccurse, that a scientist ob- serving a delicate but slow process beneath the micro- scope cannot see the full se- quence of the process. But the motion-picture camera does not tire. It sees, and records, the most minute details. We have al- ready traced, without a single break in the sequence, the 3. The embryo at the age of 56 hours. The camera is driven by a time clock that auto- matically photographs a motion picture of the embryo’s progress every few seconds 1. Fertilized egg prepared for photograph- ing, with sealed window in the top of the shell for observation of the growth within 2. Interior view of the same egg, showing the growing chick embryo only 24 hours old Me es *: weer eget enn 4. The embryo at the end of 10 days. The top picture shows Doctor Herm mak- ing these remarkable embryo photographs with his newly invented movie camera 5. At the end of 20 days. Here the embryo is shown almost fully developed, imprisoned in the shell from which it must free itself 6. Beginning to hatch. The small crack at the top of the shell shows where the chick is just beginning to pick its way through 7. The camera now gives a complete picture story of the hatching, showing how the chick breaks the shell a little at a time 8. Hatched. Still weak and wet, the new- born chick has chopped its own way out 9. Thebabychicken! From the first stir of life in the shell, the camera has recorded a continuous story of the processes of in- cubation to preserve for scientific study first stir of life within a fertile egg. We have traced | the life history of germs in: segregated living tissue! My movie photographs of the growth of the embryo within the egg, some of which are reproduced here, were ob- tained by focusing the “‘time- condénsing”’ camera into the egg, through a small window cut in the shell. It has required six years of my time to adapt the motion- picture camera to scientific uses. But now I know that the life history of disease germs will be solved; and I dare to hope that the camera may solve science’s greatest enigma—the development of embryo life. BOM RO: Aa gS

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60 POPULAR SCIENCE MONTHLY : ew Mechanical Servants Invented ‘dadddaslidduddealjdddausdddadddduMaecr EEL «wo , 1 ~ y wy ‘ a SSO RS " MDidbilh Foot pressure on a lever swings open this sanitary refuse can. A counterweight swings the can back under the cover thi Mido A twist of this little cutter is said to remove the shell clean- : ly from the top of an egg by i means of toothed spring jaws In the battle to protect clothing from moths that destroy more than $100,000,000 worth of goods yearly, this household all-metal clothing vault has been devised. Itis airtight. Within it garments are fumigated by chemicals that are said to kill the larvae as well as the moths ‘“Lddddatdbdcdcdcdddaddcdddddddddéddddééééi} LOLOL OOO Mh 3 ee YW g Here is a splashless colander. The under part of the cover has a perforated disk that presses the water from the contents. The de- vice also can be used as a baby’s bottle sterilizer This wire egg rack is designed to prevent eggs from cracking when ae inserted in boiling water. The fi handle attachment spares the fingers. The device is collapsible SQ EES [Rr Turning an indicator on this metal needlecase to the desired number, then tipping the case, delivers the size needle you want This dusting mitten can’t slip off, it is claimed, because of glovelike compartments inside SOW This combination sifter and ash- { can is said to be dustless. A pail ‘s er “Ulla filled with ashes is inserted in ' . : t the lid and covered by a sieve. Dishes are washed simply by turning Turning a handle revolves the pail A small electric heater attached to an | the handle of this machine containing electric fan can be usedfordrying thehair, boiling water and washing powder drying clothes or heating a small room al

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POPULAR SCIENCE MONTHLY ol Lighten the Housewife’s Tasks Boiling eggs without water is the feat claimed for a small electric cook- er and toaster. The eggs are placed in a perfo- rated container between two heat reflectors that radiate the heat evenly Used _ safety razor blades that otherwise ont would be thrown away fit in this ingenious potato peeler almost instantly, insuring a keen edge always. A safety guard over the blade protects the thumb of the worker hy Pressing a_ spring lever beneath this hot-pan lifter en- gages the jaws on Backaches are eliminated from iron- ing day by a newly perfected Instead of flying into the face of the electric ironer that can be operated the edge of the pan housewife, fish scales roll from while the housewife sits in a chair. under the blade of this scaler A roller controlled by an electric button is said to iron clothing of all ee : kinds, even starched garments , ’ s " Here is a midget electric range An easily adjusted gear mechanism that can be plugged into an driven by a small motor turns ordinary apartment wall socket the ice-cream freezer with ease | i ] A wrench for removing preserve- ; A small hand colander consists jar caps without breaking them One of the newest conveniences for the of a perforated semicircular plate and for lifting jars from boiling small apartment or home is an electric with a flange to hold it close water, consists of a_ gripping ironing machine that folds back out of against the edge of a pan when spring band with plier-like handles the way into the kitchen or hall closet water is drained from vegetables

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62 POPULAR SCIENCE MONTHLY Science Nears Tomb of First Man Fossils of Mongolia May Reveal Secret of Life By Truman Stevens [ise bre by the success of Expedition Starts Soon to Solve Age-Old Mystery important scientific treasures unearthed were 25 dinosaur eggs, some of them containing embryo dinosaurs. A number of eggs were found in the nest where they were laid more than 10,000,000 years ago. This discovery was the first revelation science has had that dinosaurs — huge lizard - like

their previous expedition, so startlingly productive of finds of tremendous scientific significance, a band of American scientists this spring will guide their motor cars again into the great Gobi Desert of Mongolia,

seeking to wrest from the bosom Dy eieaie eae enna ah a tell as, Sw eee of the creatures that walked the earth of the earth a scientific solution dinosaur egg (below) is eight inches; the diameter 2 4/5 inches. eons before the dawn of history of the supreme mystery of Note its elongated shape as compared with the oval hen’s egg —laid eggs and cared for their nature—the origin of man. (above), which is about 214 inches long and 17/16 inch in diameter young as do the tiny reptiles The expedition will be led by that we know today. Moreover, Roy Chapman Andrews, of the —— — en =a when the rocks about the nest American Museum of Natural es mw - = neu i gave forth 70 skulls of the History, who returned recently dinosaur Proteceratops, the layer from Mongolia after two years of the eggs and ancestor of the of exploration that resulted in great horned dinosaurs that once what have been called the most inhabited America, they sup- important and spectacular dis- plied incontrovertible evidence coveries of their kind. that Mongolia and the Rocky Mountains once were connected America and Asia Linked by land. In other words, in the early age of mammals, America These discoveries, scientists and Asia made up one continent. say, prove indubitably that North America and Asia at one The Birthplace of Man? time were linked by land, and supply all but direct evidence The explorers reason that that central Asia was the since the Mongolian plains once fountainhead from which sprang fed the ancestors of the animals human life. That Central Asia of America and Europe, the was the source of most of the ancestors of man likewise must other forms of animal life now have lived there. on earth the recent expedition Picture a hyena, more than proved virtually beyond ques- twice the size of a horse, with

tion A nest of fossilized dinosaur eggs found on the Mongolian plains. ayjaw spread of little less. than I “ h hf ™ f The eggs probably are just where they were laid more than : d bl fd ° n the search for evidence 0 10,000,000 years ago. Other eggs were discovered in the rock @ yard, capable of devouring a the birthplace of man, the ledge shown in the center of the photograph. The fossilized bones man almost in a gulp! That is scientists will seek the fossilized of a prehistoric dinosaur were found a short distance away. The the sort of creature that stalked bones of primitiv e men believed explorers assumed this huge reptile to be the one that laid the eggs through the American-Asiatic to have lain buried in the Mon- continent when man first ap- ey1° hotos tes f th sas golian rocks for millions of years. All photos courtesy of the peared on earth. The expedition That the bones are there, the Natural Hise, aad brought back with it the skull members of the expedition are of this enormous animal. certain. Larger still, though probably “I believe unquestionably not so dangerous, since it was a that Mongolia will yield the vegetable-eating animal, was remains of primitive man,” the rhinoceros of that period. said Mr. Andrews recently, The expedition also ex- speaking through courtesy humed the skull of one of the American Museum of these—the largest land of Natural History and mammal known to Asia Magazine, joint science. sponsors of his first Twenty skulls of a expedition. ‘‘We did huge beast that science not exhume the bones knows only as Titan- of the progenitors of otheres- likewise were the human race on discovered, additional our initial exploration evidence that Amer- simply because we ica and Asia once did not reach the were united; for the proper strata of rock. first fossilized speci- We learned much as men of this beast was we searched, how- found some time ago

ever, and I am con- i ™ a... biti temncen NaS, in South Dakota. fident that on our Quite as amazing in next trip we shall get Restoration of the giant browsing rhinoceros which, as far as science knows, was the its relation to the h 99 largest mammal that ever walked the earth. It was as large as a locomotive. Its fos- ird h that there. silized skull was exhumed in Mongolia by the Andrews expedition and has been placed weir changes a Probably the most on exhibition at the American Museum of Natural History, in New York City the land mass of the

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at ice als he ist an ith an is ced tie ap- ion cull bly sa was ex- one and to fa nce an- vere ynal ner- nce the eci- was ago ig in the that the earth has undergone since the beginning of creation, was another find—a vast deposit of fossils of invertebrate sea creatures. These indicated that a wide sea-way ex- tended straight through Mongolia in what geologists call the Permian times— when most of. the northefn hemisphere was below sea level. Nine Tons of Fossils Found The expedition obtained countless specimens of living animals, birds, fishes, and reptiles. In all, more than nine tons of fossils were exhumed, the largest col- lection ever taken by any expedition in a single season. In addition, a vast area was mapped, important ‘geological dis-' coveries were made, and the longest’ geological cross section ever completed in reconnaissance was executed by the scientists in their preliminary survey of the country. Ten years’ work, says Mr. Andrews, was accomplished in two summers of five months each, made possible by the fact that the expedi- tion traveled in motor cars— supported by a caravan of 75 camels. These carried gas- oline, food and other supplies to the camp sites. Thus the expedition used one of the oldest and one of the newest methods of transportation known to man. The automo- biles covered from 125 to 150 miles a day, and amazed the natives, whose laden camels : can negotiate only about 15 miles in a day’s travel. “Our expedition,” says Mr. Andrews, ‘‘was a triumph of American enterprise—not so much on the part of us who performed the work of ex- POPULAR SCIENCE MONTHLY & ploration as of those who made it possible. It was an American, Professor Henry Fairfield Osborn, president of the American Museum, who in 1900 advanced the theory that the origin of life might be found in central Asia. It was character- istic of the adventurous spirit of the American business man and his interest in science that $200,000 was advanced to back that theory. Our equipment was supplied us. Our way was made smooth. We had only to achieve our objective.” Walter Granger preparing a fossil for ship- ment. He is strengthening it with paste bandages, made of flour and old clothes Left to right: Prof. Henry Fairfield Osborn, president of the American Museum of Natural History; Roy Chapman Andrews, leader of the expedition, and Walter Granger, chief paleontologist, standing on the rim of a pit from which a large number of dinosaur bones were unearthed. Are the bones of original man close by? Pushing the expedition to its successful completion, however,;-was by no means as simple a task as Mr. Andrews modestly pictures it. The scientists met with no thrilling adventures, he declares; yet it is a matter of record that on several occasions the-members of the expedition were attacked by the giant, savage dogs that infest the country, probably the fiercest creatures on earth. The dogs feed almost entirely on human flesh, due to the Mongol custom of casting the bodies of their dead out on the plains. On one occasion a pack of fourteen of these savage brutes attacked Mr. and Mrs. Andrews as they slept in the open at night. A lucky shot from a small- caliber rifle killed the leader of the pack, and, while the other dogs devoured their fallen leader, Mr. Andrews was able to get a larger rifle and kill enough of them to send the whole pack scurrying away in panic. Venomous vipers, that constantly lodged themselves in the shoes, socks, and clothing of the explorers, constituted another danger with which the expedition contended. At first the explorers en- countered hostility from the natives, who 4 z re Heat os once ie coe a ae —_——_ ed Dinosaurs as they appeared in prehistoric ages—a_ scientific restoration from fossilized re- mains. This huge lizard-like creature measured from 60. to 80 feet from head to tail. The figure in white shows the comparative size of a man could not believe that an expedition of more than 30 members, traveling in “‘wind cars” (chi-churs), would in- vade the country for any such absurd purpose as to “hunt-bones.” This hostility was not manifested in any violent form, and it subsided rapidly when the natives understood that the quest of fossils actually was the foreigners. The leader of this epochal expedition is a slender, schol- arly appearing, soft-voiced, and gentle-mannered man of 39, a zoologist, whose place, one would say, would be in university halls rather than in pushing perilous ex- ploration through unknown lands. Yet since 1908 he has spent more of his time in adventurous research in remote re- gions of the world—Alaska, Borneo, Corea, China—than in civilization. Un- til he was placed in charge of the expedi- tion into Central Asia, his specialty had been hunting whales. He was the only naturalist who devoted himself exclusively to that thrilling and hazardous quest, and he has faced death many times. Search Will Last Five Years And now Mr. Andrews is eager, im- patient even, to return to Mongolia, where he will give five years to complet- ing his search for what he calls the “‘paleontologic Garden of Eden.” No expedition of history—not even the numerous heroic dashes for the North Pole, or the first daring voyage of Co- lumbus—ever was fraught with more thrilling and dramatic possibilities than are contained in the prospect of bridging the gulf of millions of years and solving for man the riddle of his origin. only. purpose of the white’ ee —— al oaeyS x ee eee a ccna SSE —=—s —— Se ree is a bees es wna Bere» pb Bata yt es \lieieoih tiagi pians-2ts SS ~ Seen nen Sete eae et te = eg ie Sate ee el a ge Peal hl ~ ~ “3 x Sentek eB Rr a mn oe ee

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POPULAR SCIENCE MONTHLY

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STEAM shovel mounted on endless treads recently solved uniquely a knotty problem confronting a contractor who, in building a gasoline filling station, found it necessary to move a 15,000- gallon steel storage tank, weighing nearly six tons, a quarter of a mile. Because of the enormous weight of the tank and its large dimensions—25 feet long by nine feet in diameter—ordinary hauling meth- ods were out of the question. A steam shovel near the scene gave the STEAM SHOVEL CARRIES HUGE TANK contractor his inspiration. After the dipper and dipper handle of the shovel had been removed, a chain cradle placed around the tank was made fast to the sheave block. The now shovelless shovel easily lifted the tank clear of the ground. With a man walking beside each end to prevent undue swinging, the great tank was carried the quarter mile and placed in a 12-foot excavation. The entire operation required, it is said, less than one hour.

MECHANICAL LOADER IS LABOR SAVER ae ara on the seesaw principle, a loading truck invented in Germany is said to enable one or two workmen to accomplish the work of six. Containers weighing half a ton can be handled by one man, aided by the machine, it is claimed.

A steel frame supporting a skid, con- sisting of a series of roller bearings, is mounted seesaw fashion on a stout sup- port that rests on a three-wheel truck. The loading frame or skid has at one enda platform that rests on the ground to receive the load. Theworkman, turn- ing a crank, raises the loading skid until the end opposite the load is lower than the ful- crum of the seesaw. The load then rolls down the rollers of the skid to the car or truck. The loader can be wheeledeasilyfrom placetoplace. During loading it is held sta- tionary by brakes.

Above: The skid ele- vated to an inclined position, permitting lifted barrels to be rolled on roller bear- ings to the truck. At the right: Loading a packing case on the lift platform. When the operator turns a crank, the pivoted see- saw skid is elevated to the slightly inclined position shown above

How to Shut: Off Water in Repairing Faucet Eigen problem of the leaking water faucet is one that presents itself occasionally to almost every home owner. Usually the cause of the leak lies in a washer that has become worn. To replace it with a new washer is a simple job; but first the water must beturned off or the pres- sure in the pipes re- duced. In case it is found im- possible to shut off the water from the house, a plan recommended by experts is to turn on all the faucets in the house. This will reduce the pressure sufficiently to permit work on the damaged faucet. Electric Motor Drives the Old Farm Pump

Reduced pressure per- mits work on the faucet

Well pump with electric motor attached bie of electric power on the farm has progressed to a point where even the old-time hand pump is driven by motor. Designed especially for this purpose, a newly perfected motor of one quarter or one half horsepower, inclosed by a rust- resisting metal box, drives the pump at 35 strokes a minute. The length of the stroke can be adjusted,to accommodate various well depths and cylinder lengths. Either alternating or direct current can be used. A pushbutton starts and stops the pumping. The mechanism can be in- stalled in an hour, it is claimed, and soon will pay for itself in saving the time and labor of the farmer.

THE Editor will be glad to supply, wherever possible, the names and ad- dresses of manufacturers of devices mentioned in this issue.

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elf er. La the s is ise. tly | the otor. se, a rr or rust- p at the date ths. ; can stops e in- soon } and pply, ad- vices Every Pile of Tin Cans Is an Iron Mine 7 sorry procession of empty tin cans that passes continually through your back door to ignominious oblivion soon may be knocking at your front door in the form of brackets for your walls, sash weights for your windows, griddles for your kitchen stove, and grates for your furnace. In a series of experiments recently concluded by the Northwest Experiment Station of the Bureau of Mines, Seattle, the Great American Can has been con- verted successfully into synthetic iron for any use to which ordinary pig iron can be put. The millions of cans that are wasted each year (from 160 to 200 are used by each of the 25,000,000 families in the United States) contain very little tin. All but one per cent is iron. The problem of salvaging them heretofore has been the difficulty of separating the tin from the iron so that the latter might be used. The melting temperature of tin is 232° C., while that of iron is 1560° C. Attempts to melt all the tin off proved unsuccessful. But the Seattle experi- menters overcame this limitation by adding scrap iron to the metal obtained from melting the can scrap, thus reducing the proportion of tin by diluting it. Heavy sections and thin crnamental POPULAR SCIENCE MONTHLY wee s nae Above: A sea of tin cans waitingX\to be used and thrown away. Right: The laboratory where cans are converted into usable iron castings were made of the new metal. It was found to be amply soft, and to yield properly to a carbon drill or lathe. Small Tractor Converted into Power Shovel HE small tractor can be converted quickly into a diminutive and mobile power shovel when equipped with a’ recently patented attachment consisting of a broad shovel, holding half a cubic yard, and fastened to the front and rear axles of the tractor. The machine is especially useful on small jobs such as digging cellars, ditching, loading wagons or shoveling snow. Power for raising and lowering the shovel is. supplied by the tractor engine through a pulley attached to the right side of the tractor. A steel rope passing around a drum at the rear, operated by a trip lever beside the driver, manipulates the shovel. The driver sends the tractor forward in low gear. A lever lowers and raises the shovel as required. Tractor-power shovel used for excavating One Man Controls Great U. S. Dreadnaught blige n brain of Uncle Sam’s mighty dreadnaught Colorado is in the little room shown above. From it every movement of the great war-ship can be governed by one man through a mar- velous electrical control system. The long levers control 30,000-horsepower electric propelling motors. The short handles control the throttle valves of giant steam turbines. These turbines drive electric generators that provide the power for the electric motors. The motors, in their turn, drive the great propeller shafts. One-man control is the last word in the navigation of battle-ships. Heretofore six.men have been required as a control- room crew. Car-Drawn Mower Cuts Weeds along Tracks i apeiron along the tracks of an inter- urban trolley company of Rock- ford, Ill., caused considerable trouble and expense every summer, until an employee of the company hit upon the idea of hitching a mowing machine, of the type commonly used on the small farm, to a trolley car and hauling it over the right of way. By the new arrangement, the mowing machine is equipped with flanged wheels to fit the tracks and the tongue of the machine is attached to the rear of a car. As the mower is hauled along the tracks, the cutting blades can be raised or lowered.

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Pe he * mad Spent ARSE ROT ste gS y3 Z Ee pede t eer . an ame * —.s i" > =" } i Wl POPULAR SCIENCE MONTHLY DIGS AND LOADS BY COMPRESSED AIR Fs a UNUSUAL digging machine that combines the processes of shoveling and loading is finding its way into hun- dreds of mining and construction jobs. It is operated and driven entirely by compressed air. The speed of the loading can be con- trolled so as to throw the material to the farther end of a long car, or merely to drop it into a short one. The mechanical shovel will dump its load into the center of the car from any position, even extreme right or left, it is claimed. Compressed-air power is applied through direct thrust cylinders. Three control levers successively crowd, dig, and dump the shovel. The two middle cylinders, acting as one, which do the main digging, are provided with cataract oil escapement plunger pis- tons. This arrangement is declared to give a steady and controlled but fast movement, from the first of crowding to the last of dumping, permitting no build- ing up of pressure and consequent jump- ing, or throwing out of the load. Penny-in-Slot Elevator PENNY-IN-THE-SLOT automatic elevator recently has been invented. Inserting a coin, the passenger enters the car and presses a button displaying the number of the floor he wants. The car automatically stops at that floor. BOY LIFTS HALF A =o ss H GEAR HIS novel form of hand lifting gear, by which a small boy may raise half a ton weight as high as 100 feet, has been devised by an Eng- lish manufacturer. The apparatus is operated by turning a_ short handle, bolted to a sprocket wheel. This wheel has one less tooth than the in- ternal gear with which it is connected. The in- ternal gear consequently advances slightly farther than the external wheel as the latter is revolved. This difference is utilized in winding a chain that lifts the desired load. Braking and lowering are contPolled by a drum and pawl mechanism that prevents the hoist from overrunning when the handle is released. A comparatively slight force applied to the handle will suffice to raise a great weight. The device finds its principal use in warehouses, ga- rages, motor works, and on small craft. Useful Hand Vise Lathe for Shop or enn ESIGNED> especially for garage own- eau ers, . {3 auto Ray owners, farmers, ‘ and machinists, a small but ver- satile hand vise lathe, recently invented, will make from bar stock such ar- ticles as milled studs, setscrews, cap screws, pins, and many other special screws and studs with- out using an en- gine lathe or automatic screw machine. The tool also winds wire springs with any pitch de- sired. Bar stock up to and including one inch in diam- eter can be handled. Any required length of screw, stud or spring can be made easily, it is said. Perfect accuracy is claimed. Since the device is hand-fed, the operator can make a fine or heavy cut as the occasion requires. BAR STOCK HELD IN , VISE The hand vise lathe A New Comparator Gage NDICATING to the thousandth of an inch any variation of a piece of work from a precise standard, a new comparator gage has been designed to supplant the snap and limit gage in repetition or pro- duction work. . The. gage is set so that if the work measured is exactly standard size, it will give a-zero reading. The slightest devia- tionsfrom the standard areshown onadial. ADJUSTABLE HEAD ANVIL 2 The micrometer gage and its measuring dial In operation, the dial is turned back sufficiently to allow the work to clear the head of a measuring spindle. The spindle is held by an automatic brake. As the work being measured touches a releasing button, the brake is released and the measuring spindle is rotated by a driving spring until it contacts with the work. In this contact position it is locked and the reading appears on the dial.

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cy od, ut an rk tor she ro- rk vill ia- al. ck he lle he ng he ng In he cs wit ENDLESS TREAD ENGINE PULLS POPULAR SCIENCE MONTHLY SLE D 67 i a SS a aes TRAIN OF LOGS This logging sled train is hauled over the snow by a steam locomotive running on endless treads. The engine pulls 15 “‘cars’’ DREDGING WITH A CHAIN OF BUCKETS 5 hee alternative of a costly winter shutdown or the almost as costly use of an army of horses and drivers is cir- cumvented by a northern lumber com- pany through the use of endless tread steam engines and sled trains. Fifteen heavily loaded cars of logs can be hauled at a time over the snow by the steam tractor, which equals the work of 60 teams and their drivers. Moreover, the engine burns wood, while the horses ate costly oats. The main body of the engine runs on endless treads and the forward part is shod with sleds. The cars run on sleds. An engineer, a fireman, and four lumber- jacks can operate one of the trains over the long distances from forest to mill. Offset Drill Bores Holes in Awkward Places A» OFFSET drilling attachment has 4% been perfected by a ‘concern in Bridgeport, Conn., to overcome a diffi- culty that mechanics often encounter— that of drilling and counterboring holes in unusual and out-of-the-way places where the usual machines will not serve the purpose. The attachment is so arranged that it may be swiveled around the center of the drill press spindle to the most convenient position. The rotation of the drill spindle is transmitted to the vertical drilling tool at the end of the offset through a square shaft. The extremely small distance between the tool point and the top of the offset arm permits operation in the most cramped ‘corners. PERATING on the endless chain principle, this new dredger is said to represent a distinct improvement over the usual suction type. Digging buckets in an endless chain move about a huge shaft that is lowered diagonally into the water through a well in the bow of the dredging barge, as shown below. .A huge arm carrying a chain of buckets is lowered through a well in the bow NEW DIESEL ENGINE HAS -DISK DRIVE A RADICAL departure in Diesel + 4 marine engine design is found in a new crankless, ‘two-cylinder machine utilizing the principle of the oscillating disk to transform reciprocating into rotary motion. Each of the two cylinders has two pistons, one at each end, attached through ball-and-socket joints to the oscillating stroke, when a jet of oil is shot into the cylinder and mixed with air. The power stroke of the pistons in one cylinder forces the pistons of the opposite cylinder together, compressing and ex- ploding the gaseous mixture. Pressure of the pistons on the sides of the tilted disks operate the drive shaft. disks or thrust plates. While the pistons of one cylinder are mov- ing inward on the compression stroke, those of the other cylinder are moving outward on the power stroke. The intake is on the power \ OSCILLATING DISKS Above: General view of a light and powerful marine Diesel engine of the new type, show- ing hand lever for pro- ducing initial oil pres- sure. At the left: Plan of engine, showing ar- rangement of cylinders and oscillating disks that exert a thrust on the drive shaft

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ee _ permit sto POPULAR SCIENCE MONTHLY hl MEW SS BW. SW W\QQ*H\{\&UEAAW NN Airplane Transports Carrier Pigeons UCCESSFUL use of the airplane’ in transporting carrier pigeons was demon- strated recently at an aerodrome at Bourget, near Paris, France, where a machine espe- cially designed for the purpose arrived safely from Ghent, Belgium. The upper photograph shows the pigeons be- ing released. Part of the immense pigeon house in the fuselage is shown at the left. This method insures good cage ventilation. A Shave at High Speed by Motorcycle Barber O LONGER need the hurried busi- ness man slash ruthlessly at his face in the mornin¢ in a desperate race against time to catch the 8:20 train. A motor- cycle barber shop, in which he can enjoy all the comforts of a clean shave by an expert barber while he speeds along the streets on the way to his office, is the latest motorized novelty to be introduced at Los Angeles, Calif. The customer sits in a motorcycle side car, which is equipped with an extra seat for the barber just behind the driver’s seat. A small electric heater provides plenty of hot water for the shave. A regulation barber pole surmounts the hood of the sidecar. The motorcycle barber shop: Giving the business man a clean shave on the way to work. Note barber pole in front of car First Prize, $20 By John Boyd, Flint, Mich. 5 jason I had an opportunity to go on a bench job in an auto- mobile factory, I determined to make good. My mettle was challenged, be- cause my predecessor had been unable to produce up to expectations. I analyzed the problem. Of the four operations involved on each piece, the second and third caused the trouble. The second was to loosen a nut on a bolt, it being necessary to hold the bolt head. I drove a socket wrench into the wooden bench. Thus I could put the bolt head into the socket and have both hands free for loosening. This cut in half the time required. The third operation was to turn a collar held by this bolt until it was alined with a second collar. The first invariably was stuck with dried paint and had to be hammered into place. I made a U-shaped bracket and set the collar in it. Then I could turn the casing in the collar, which was equiva- lent to turning the collar itself. CONTEST WINNERS TELL HOW THEIR INVENTIONS PAID The prize-winning letters in the POPULAR SCIENCE MONTHLY contest, ‘“‘What a Small Invention Did for Me’’ Second Prize, $10 By C. R. Mullin, Minneapolis, Minn. [N THE newspaper office where I began as a printer’s devil, the press was used long after the size of the paper had outgrown it. The capacity of the press was an eight-page paper, but. 12 pages was the usual size and special editions often were much larger. This meant that the paper had to be printed in two parts, one being in- serted in the other by hand. The room was very small, so that it was seriously crowded at press time by this work. Carrying the papers into another room would have been too costly in time. So I picked up an old tape roller and the necessary tapes around the shop and built an extension on the -outlet of the press. This carried the papers to an extra table, about two feet away. As the papers came from the press with the proper edge toward the workers, two persons were able to do the work of stuffing. This required but one table. Third Prize, $5 By Howard W. Reid, Detroit, Mich. RACs week our plant accumulates 1000 pounds of yarn through which are twisted strands of copper wire. To salvage this by hand cost $13,000 a year. I mounted two drafting rollers on a special frame. To each of these were fitted two grooved pulleys. A roller that could be moved at will was placed upon the drafting rollers. Back of the pulleys was a set of rotary rollers, fiber covered and mounted on a hollow shaft. This shaft had a grooved pulley, behind which was a sheet-iron protector with a hole directly opposite the hollow shaft. Beneath the roller mounting were the drive mechanism gears and a small motor. Web bands served for drives. The yarn was hooked in a wire eye- let and dropped down as the other end was passed into the rotary roller and started through the drafting rollers. This kept the yarn from being tangled by the whirling of the rollers.

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World’s Largest Vacuum Tube Perfect Model ~ HE world’s largest vacuum tube—a. complete working model: of- the well known dry cell tube that brought radio’ within the grasp of the average American: —was constructed by an electrical manu- facturing concern for display purposes. With its filament lighted to full brilliance, it presents a most attractive picture. It need hardly be mentioned, however, that the electricity it consumes requires a source of current far beyond the limit of such a dry cell as is used in a radio receiver. Just try to picture the size of the radio set in which several tubes of these propor- tions could be operated. Giant model of dry cell radio tube Doctor Says Auto Driving Makes Us Pigeon-Toed S A result of continual automobile driving, Americans are becoming pigeon-teed, according to the statement of Dr. Carl Hunt, of New York City, after extensive research to determine the cause of a marked tendency to “toe in’”’ on the part of a large percentage of the population in large cities. Complaints of pains in the right foot, which are be- coming common, also are attributed by him to the same cause. “Automobile drivers are developing 2 new form of foot trouble that in many cases becomes actual deformity,” says Dr. Hunt. “Ever since the advent of the foot accelerator, my car-driving patients, in ever increasing numbers, have com- plained of pains in the outer side of the middle third of the. right foot, par- ticularly when walking. In most cases I have found that with correction of the position of the foot on the accelerator, manual manipulations, simple exercises, and properly fitting shoes, the trouble has disappeared.” ‘ POPULAR SCIENCE MONTHLY Brothers Hike across Bay on Water Shoes | ements across San Francisco Bay recently, A. N. Sheldon, inventor of ingenious water shoes that made the feat possible, with his brother scored man’s latest conquest of the water. These shoes are 10 feet long and 14 inches wide, and of pontoon construction. They are walked with much as one walks with snowshoes. A top framework prevents the pontoons from spreading sidewise, at the same time accommodat- ing the alternation of thestride. Handle- bars aid in steering the course, which, although slow, is said to be safe and certain. The decks of the “shoe pontoons’”’ are covered, except for four small openings just large enough for the two operators to insert their feet. Bicycle saddles mounted on the frame- work enable the walkers to rest. = y Side and frgnt views of the water shoes FOREFATHER OF MODERN SUBMARINES ERE is one of the world’s first sub- marine boats, built in 1864, by Messrs. Bushnell-Rice and Halstead of New Jersey, and now one of the relics on exhibition at the Brooklyn Navy Yard, New York. It had a speed of four knots and was propelled by hand. A crew of 10 men was carried, although it was only 28 feet long and nine feet high. The cost was $60,000. The first successful submarine vessel was by David Bushnell in Americain 1775. The hande-propelled submarine, built in 1864, on exhibition at the Brooklyn Navy Yard, N. ¥. - a

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POPULAR SCIENCE MONTHLY Sree eee TING sunlight to an in- tensity sufficient to melt ore, this reflecting apparatus, perfected recently by William Thomas, Los Angeles physicist, formerly an engineer with Thomas Edi- son, seems to mark an advance in the attempt to harness more sun energy. The sunlight strikes sixteen 30-inch O LOCATE and rescue lifeboats or other small craft lost from their mother ships in fog or storm, a simple underwater signaling system has been perfected. It consists of a portable direction finder for the mother ship, and a sounding device, also portable, for each small craft. The direction finder, which is lowered into the water, is an inverted metal Y about four feet long. A rubber bulb at the end of each arm receives and trans- mits the signals to the ears of thé listener through stethoscope binaurals. CONCENTRATED SUNSHINE MELTS ORE panes, each set at such an angle that the rays are reflected, considerably concen- trated, upon another set of panes oppo- site. From these the rays focus on a spot six inches square. Thus, the heat normally distributed over 24 square feet is concentrated to fall upon an area of 36 square inches. UNDERWATER SIGNALS RESCUE BOATS The sounder consists of an inverted metal cup at the end of a metal rod. The cup end is submerged, and the upper end of the rod is struck with a hammer. The sound waves thus produced are said to carry several miles under water. Above: Lowering the V-shaped direction finder into the water. The upper inset shows how signals are sent by striking a metal rod attached to a submerged sounding device. At the right: Listening to signals Carbonic-Acid Gas Said to Fertilize Gardens [NCREASES in vegetable yields rang- ing from 35 to 175 per cent are said to have been achieved recently by German agricultural experts through the use of How the size of potatoes was increased by fertilizing them with carbonic-acid gas carbonic-acid gas as a soil fertilizer. Since carbonic-acid gas is formed in combustion, waste gas from a mine and foundry near Essen, Germany, was used in the experiments. After being purified, this gas was led through pipes with per- forations to hothouses and open fields. In both cases astonishingly favorable re- sults were reported. Much more rapid development and a 70 per cent increase in yield are claimed to have resulted from supplying the gas to cucumbers. Tomatoes were said to _ be increased 275 per cent. Largest Camera Lens Used to Photograph Stars NE of the world’s largest cameras was made recently by the United States Bureau of Standards to photograph astro- nomical observations. It is six feet long, four feet wide, and 2% feet high. It uses plates 11 by 14 inches. The lens is said to be the largest photographic camera lens ever manufactured in the United States. Ocean Currents Measured by Floating Bottles NOWLEDGE of the direction and speed of ocean currents is of great importance to navigators. Since it is difficult to measure these directly, the United States Hydrographic Office accom- plishes it approximately by means of what are known as “bottle papers.” These are small paper slips with directions for their return to the proper authorities printed in several languages. Sealed in bottles, they are given to ships’ captains, and thrown overboard. On them are writ- ten the time and place they are launched. After months or years they return to Washington. One drifted nearly across the Atlantic and back.

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Potato Bugs Speared to Death by Enemies As.) the devastating potato bug, the United States Department of Agriculture is marshaling an army of enemy soldier bugs, popularly known as “stink bugs.” Every time a potato parasite clashes with one of these deadly antagonists, potato plants are just one bug safer. For the soldier bug usually wins. Advancing to the attack, he jabs a spearlike beak into a soft spot in his prey’s armor. Barbs at the tips of the jaws keep the spear inserted. The doomed potato bug at first feigns death, then begins a frantic scrambling over obstacles to shake off its assailant. Exhaustion finally leaves the potato bug at the mercy of the soldier bug’s appetite, which sates itself on the blood and juices of the victim. Soldier bug feasting on potato bug Jolting Machine Tests Strength of Boxes Ng canpenpipoerdes the bumping and sway- ing of a moving freight car, a machine recently designed by the Forest Products Laboratory of the United States Depart- ment of Agriculture, tests the strength of box containers for merchandise in trans- portation. A table to which the box being tested is attached moves backward and forward on wheels over a distance of several inches. The wheels roll on rails at each side. The shaking effect may be varied by accelerating or slowing the machine. Testing a box on the shaking table POPULAR SCIENCE MONTHLY 71 Clock Shows Movements of Planets and Satellites N AMAZINGLY intricate 10-dial astronomical clock that records mi- nutely the movements of each planet and satellite of our solar system has been in- vented by Oswald Schulz of Berlin. Since each of these bodies has a char- acteristic set of movements, this is an astonishing mechanical achievement. The clock has no springs and operates only while the crank shown at the side is turned. The upper illustration shows the stripped mechanism. The lower records the eclip- tic rotation of the moon about the earth. L This dial shows the movement of the moon around the earth. Top: The solar clock, un- covered, showing the intricate mechanism The inventor demonstrating his sun engine Sun’s Rays Bottled to Drive Steam Engine _ CONVERTING the energy of sun- light into the energy of steam with an ingeniously contrived reflector, Bernard A. Grossman, a young New: York physi- cist, believes he has found a method of bottling solar energy for use on a large scale in producing cheap power. The reflector consists of a series of para- bolic mirrors arranged in such a way that they concentrate sun rays upon a small boiler, producing steam. The energy thus produced, Grossman declares, may be translated into electrical energy by run- ning a steam engine and generator. Crime Suspects Tested by Detective Machine UILTY secrets are said to be bared unerringly by a delicate “third de- gree’ apparatus invented recently by Dr. Albert Schneider of the University of California. The suspect places the forefinger of each hand on contacts from which run minute wires to a capillary electrometer, an arrangement of glass tubing. Through one tube runs a fine thread of mercury. Fluctuations of the mercury are said to betray the suspect. Doctor Schneider and his crime detector Ae SERN SS nin ae on a y Sth EES en ae ir eres

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iS © van i FFmpeg a fam ts nin aoe POPULAR SCIENCE MONTHLY ROAD LINES SIMPLIFY 4 k-th auto brakes is made easy for the motorist by traffic authorities of Hartford, Conn. Just outside the con- gested area of the city, on road stretches selected because they are smooth and level, offering little possibility of collision, are painted the testing directions and white lines shown above. ELECTRIC SPARKS per blue-green flash of a sparking elec- tric trolley, piercing a fog, inspired an idea that has developed into a power- ful fog-piercing signal light as a safeguard to navigation. R. C. Douglas, a San Francisco jewelry salesman, is the inventor who saw the flash and who realized the possibility of using quickly drawn out electric sparks for effective fog-signal lights. Today the results of his ingenuity and patience are found on San Francisco ferries and pier- heads, guiding ships through the fogs. The lights are said to penetrate dense fog mor2 than 1000 feet beyond the reach of the eye, locating passing vessels. A motor-driven gear mechanism in a hooded space at the top of the light raises and lowers a thick electrode upon the up- turned tip of another electrode. These two electrodes form the make-and-break point of a 110-volt electric circuit. The periodically formed gap is drawn out or widened two or three inches as the current BRAKE TESTS The lines are 20 feet apart. The driver is to cross the first line at exactly 15 miles an hour, applying his brakes full force at the instant of crossing. If he stops at or short of the second line, his brakes are in sound order. The lines and directions are repainted at necessary intervals. AS FOG SIGNALS is leaping it. The flaming arc becomes remarkably active as it seeks to fill the widening space, simultaneously creating a penetrating, flashing fog light. Douglas is continuing experiments with his invention, in an effort to increase still further the intensity of the light and thereby extend its usefulness. Above: The in- ventor, with eyes protected by mask and goggles, experi- menting with his new fog signal light to increase the in- tensity of electric flashes At the left: One of the lights set up on a pierhead at San Francisco to: guide ferry-boats and other craft during heavy fogs Camera Range Finder for Sharper Photographs A PHOTOGRAPHIC range finder, us- ing the principle that served gunners in the Great War, has been perfected in England. It is claimed to insure sharp photographs under favorable light condi- tions irrespective of the size of the camera lens aperture. The invention is contained in a small metal box three inches high and seven eighths of an inch square, compact enough for the vest pocket, yet easily attached to a camera. Looking into the finder through the top aperture; the photographersees two misplaced halves of an image, like those in the lower illustration. An adjusting Above: The range finder attached to a camera. Below: The reflected image of a distant dirigible. Range is determined by bringing the halves of the image together screw at the side of the finder is manipu- lated to justify the halves. The distance of the object from the camera then can be read off on a scale and the camera focused accordingly. Within the finder are two mirrors, one above the other. The bottom mirror is fixed, while a smaller one at the top is movable, and-is adjusted by the screw. Each mirror reflects an image of a portion of the object to be photographed. If the mirrors are parallel, the two reflections do not fit together. . By turning the adjusting screw until the top mirror is at the correct angle to make the images fit, a pointer records the exact distance of the object that is being photographed. Corrugated Blade Slices Potatoes for Frying PPETIZ- ING lat- ticed potatoes for frying — potatoes cut in thin corru- gated _ slices like the two shown in the illustration— can be made speedily with a handy cutter that rests on the top of the kitchen table After the potatoes are peeled, they ar: forced with quick strokes against a shar, corrugated cutting blade.

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r rs ed rp di- Ta en gh to gh wo ng til er le rp Fishing Gun Casts Line without a Rod OTORISTS, campers, and _ hikers who may want to fish, but who do not wish to include a more or less cum- bersome rod in their equip- ment, may enjoy the sport notwithstanding, through the invention of a rodless casting reel that has just been put on the market by a New York manufacturer. This may be described as a fishing gun contain- ing a spring that shoots the line from the reel when a trigger is pressed. The fish may be played from the reel as with a rod. Accurate casting is possible from the shores of bays, lakes, or streams or into the surf, the makers declare. The device is especially useful for those who desire to fish from boats. It weighs 19 ounces, is 9% inches long, and has a capacity of 80 yards of line. The alu- minum handle is hollow to permit the stor- ing of bobbin, sinker, flies, and hooks. If desired, a rod may be used. Shoe Shining Made Easier by Portable Cabinet HE new portable shoe-shining cabinet shown below has an inclined corru- gated rubber rest surface for the foot, a polish container that swings out to a handy position, a two-headed dauber brush and a double wool polisher with a reversible leatherette to protect the hands. The cabinet is opened from the side by unlatching a simple catch. Four rubber feet on the bottom prevent scratch- ing the floor. aes One of the chief advantages of the out- fit is its compactness. Nearly every person has used one of the old-time, clumsy shoe boxes that was about the size of a small chair and always in the way wherever it was placed. The new box, when not in use, can be put out of sight under a table or in a closet. i rh - pueeenenanoes | The outfit, showing compact cabinet POPULAR SCIENCE MONTHLY 73 OR centuries houses have been ex- panded by horizontal extensions. But now a schoolhouse in Washington, D. C., is being expanded upward. The entire roof, 150 feet by 75 feet, of the two-story CHOOL ROOF TO ADD A FLOOR Thompson grade school, has been jacked ; up 12 feet to permit the building of a third floor. The plan is said to have proved most practicable and economical. New Rustless Mailboxes Made of Brass O RESIST the destructive, rust- producing effects of salt-tinged air, brass mailboxes are being introduced in a number of coast cities. Whereas such air is said to destroy the usual steel box within three years, the new brass recep- tacles are claimed to be immune to its action. This resistant quality of brass makes it unnecessary to paint the new boxes the familiar green. The photograph shows New York’s first brass box, on Broadway near Wall Street, being initiated. THE Editor will be glad to supply, wherever possible, the names and addresses of manufacturers of de- vices mentioned in this issue. Electric Hammer Has Single Moving Part ‘AN ELECTRIC hammer with only one moving part has been designed for use by mechanics, builders, and manu- facturers. The power tool will drill a one- inch hole three inches deep in concrete in one minute, it ig claimed, and can be operated on slightly less current than would be required for an electric iron. Alternating current is necesary. The hammer strikes 60 blows a second, while the operator pulls a trigger. The single moving part is a hardened steel hammer that moves back and forth within a bronze barrel. At each end of the barrel is a coil of wire. These coils alternately become temporary magnets as the alternating current passes through them, driving and withdrawing the hammer, Using the electric hammer as a riveter Sar genes Be mare : DATARS. ee Te ~ aS erence sexeeer ns One eon ‘ for — Se ao yer ee eae ee eee SSRN. Sa sae MLSE MAMET LG Re ASN PRET ANTE ES pamtrer jews 3 rk Ps Ti

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jaelinm” ee EE Yee, UF ARNE S ent aah, 26 EE RNR LS MN 74 Feeding the Crowds x POPULAR SCIENCE MONTHLY by Machinery Behind the Scenes in a Modern Restaurant By Edward Woodward S YOU have sat in one of our great modern restau- rants or hotel dining- rooms during the crowded lunch hour, have you not marveled at the apparent ease and swiftness with which the wants of hungry hundreds are served—all at once? On every table, beside every place, are the inevitable bread and butter. Who bakes the hundreds of loaves? Who cuts the thousands of slices? Nearly every one has ordered po- tatoes. Who is the gal- ley boy that peels them? The answer is—ma- chinery. Mechanical science has replaced hand labor in modern restaurant kitchens, just as it is replacing drudgery in the modern American home. Consider the single item of bread in a restaurant that feeds, say, 400 persons at one time. You can imagine what an army of bread slicers would be re- quired to serve such a crowd quickly. Yet a machine oper- ated in large modern restaurants cuts 200 slices a minute—or a slice for every one of the 400 in two minutes! This electrical device takes loaves 24 inches long and cuts them with such nicety that !all slices are of exactly the same thickness. Bread-Making Is Automatic And while the bread is being sliced, another machine cuts dozens of little squares of butter at a single pressing. In fact, a remarkable apparatus _re- cently invented for use where large numbers of sandwiches are required, not only slices the bread, but neatly butters each slice in the same operation! In the most improved bread-making equipment the entire process is auto- matic from the time the dough is pre- pared in the kitchen. First, a divider and scale mechanism weighs and cuts the dough to the proper size. Another machine then rounds the dough and passes it on to a third apparatus, which kneads it until it is light and fluffy. A molder gives the dough its final shape, and it is ready for the ovens. The latest automatic electric baking apparatus has an output of from 1600 to 3200 loaves an hour, yet requires only | CONVEYOR BRINGS RAW FOODS TO COOKING RANGES Part of the kitchen in a New York hotel. Note the power-driven con- veyor, above the heads of the chefs, that carries raw foods to the ranges At the left is shown a re- One of the newest types of automatic electric bake oven, in which bread baking is reduced to simple timing control into little individual pitchers, an ounce at a time. At every meal, po- tatoes, like bread, are demanded in enormous quantities. An auto- matic machine peels three pecks of potatoes in three quarters of a minute. This apparatus is a great cylinder, the bottom of which is a re- volving disk. The in- terior is lined with spe- cial concrete facing. As the potatoes are whirled around swiftly in the cylinder, they are knocked against the sides. The impact re- moves the skins in small flakes without bruising the potatoes. Asmall stream of water plays continually on the vegetables, washing markable new machine that not only slices loaves of bread, but butters each slice in the same swift operation away the residue. Car- rots, turnips, onions, and other vegetables are prepared for the two attendants to operate it. Here the science of baking becomes simply a matter of timing. ~ When one loaf is baked, all are baked, and all are uniform in quality. This is made possible by automatic temperature control. Not so many years ago, breakfast— the regulation American morning meal of cereal, eggs, toast, and coffee—was one of the greatest problems of the restau- rant owner. Today, machinery has made it one of the simplest. Toast, that formerly took a long time to prepare and required much individual attention, now is made at the rate of a dozen pieces at a time on an electric grill that auto- matically turns the pieces when they are brown, and toasts both sides evenly. Eggs, that must be boiled an exact number of minutes and half minutes, according to the individual taste of each patron, now can be cooked in a machine that dips them in boiling water, times them, and automatically takes them out of the water when their time is up. Coffee can be made 40 gallons at a time—enough to supply 600 diners. Cream for the coffee is measured au- tomatically by a machine that pours it pot by the same type of machine. For nearly every different way of serv- ing potatoes there is a special machine. A motorized masher that operates like an egg-beater whips and mashes them at the rate of a peck a minute. Another machine slices the potatoes in uniform pieces for French frying. Two Hundred Cakes a Minute Cakes, pies, and other pastry that once tried the skill of every cook, can be turned out by the dozens at the press of a button. An automatic sponge-cake beater will beat 30 quarts of cake batter to feathery consistency. And when the electric oven has baked the batter to an even, appetizing brown, another machine drops the cakes out at the rate of 200 cakes a minute! Pie crust is made by a motorized roller. And when the pie is in the dish, before it is put in the oven, a machine presses the rim of the crust down evenly _ and clips off the extra dough, while still another machine marks and crimps it. These are just a few of the marvels of scientific cookery as it is practised today. Others are shown on the opposite page.

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POPULAR .SCIENCE MONFHLY Above is a typical view in a_ great modern restaurant during the lunch hour. To feed these hundreds of per- sons all at one time requires not only ingenious auto- matic machines that turn out food in large quantities, but also high-speed conveyor systems to carry food and dishes from the kitchens to the im- mense dining room Below is a new heavy-duty dish- washing machine, said to have a capacity of 12,000 pieces an hour. It does the work of an army of cleaners. The soiled dishes, in racks, are inserted in the machine. In a few seconds they are thoroughly scoured ’ ELEVATORS TO FLOOR KITCHE) ORDERS RECEIVED AND TRANSCRIBED HERE At the left is the soup kitchen of an up-to-date restau- rant. The soup is cooked in a battery of enormous ket- tles, where the heat is controlled auto- matically, and is drawn off through spigots at the bot- tom of the kettles into serving buck- ets. These kettles hold enough soup to feed a thousand To save time and economize in space, elevators and other conveying apparatus are employed to carry food from kitchens to service- and dining-rooms on other floors. This kind of ma- chinery has made it pos- sible to prepare the food on several floors and to serve it in the dining-room without the slightest loss of time Below: Silver-cleaning appa- ratus. The silver is cleaned b; burnishing. It is immersed in a bath of small steel particles— highly polished balls and pins— that reach the otherwise inac- cessible parts. These polish without wearing away the plate exes SILVER-POLISHERS a ag nent ? cr pee a

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me ROE Seer PEE PSA CERO — pmpepage eer T et AES IE AT a. EOLA Ry RSE = 2 76 POPULAR SCIENCE MONTHLY . ENGINE SUPPLIES phicambaiacsiin FOR sche incnshociaaa GEARSHIFT N AUTO- MATIC gear- shift, oper- ated by vacuum supplied by the en- gine and regulated by buttons at the rim of the steering gear, has been de- veloped by a Pitts- burgh manufacturer and recently offered to motorists. Unlike electric shifts and other sub- stitutes for the standard lever, this new method requires no additional power installation, beyond that already sup- plied by the motor. It is said to be quick, safe, and easy of operation, insuring proper meshing of gears under any condition of driving and permitting a selective shift. A pipe connected with the intake mani- fold supplies the vacuum by which the shifts are made. This pipe is connected with a series of cylinders, corresponding to first, second, third, and reverse gears. To shift gears, the operator presses one of a set of buttons at the steering wheel, cor- responding to the gear desired. This button operates a valve that causes the motor to withdraw the air from the cylinder that controls the movements of the gear. When the clutch pedal is pushed to the floor and released, the gear mechanism is unlocked and the desired shift made. By the vacuum control system it is possible to prepare for anticipated shifts in advance. Then movement of the clutch pedal will make the necessary shift with- out the need of removing the hands from CAP REPLACES CON} L LEVER Above: The driv- er’s control mech- anism of the vacu- um gearshift, show- ing selector buttons for first, second, third, reverse, and neutral in a valve box close to the wheel. The layout of the entire vacu- um system is shown in the diagram CLUTCH PEDAL This is said to fur. nish much faster and more certain control of speed and a quicker “‘pick-up,” Stripping the gears by forcing them to engage at improper speeds jg said to be impos. sible with vacuum control, since the operation is per. formed automati- cally. The valve box contains five but- tons for three for. ward speeds and reverse and neutral, It is impossible to shift to reverse acci- dentally, since the neutral button must be used first before it is possible to put the car in reverse. The apparatus, it is said, can be in- stalled in a _ few hours by an experi- enced mechanic on any car having se lective transmission. VALVE BOX ON STEERING POST the wheel, which means additional safety. When the motor is idling, sufficient power is generated, it is said, to permit the shift to be made from neutral to first speed with surety, even on cold days when the lubricant in the transmission case is stiff and sluggish. By partly engaging the clutch after one shift has been prepared, and then setting the button for the next shift, it is possible to engage the clutch and then pass at once to the next speed by pressing the pedal and engaging again. It requires no al- teration of _ the instrument board, steering post, or floor controls. A one-inch hole in the flooring to permit the entrance of the pipe from the valve box is the only alteration necessary. The gear lever is of course re- moved, and in its place is installed a pol- ished cap that may be removed to lubn- cate the transmission. The manufacturers assert the vacuum gear control costs nothing to operate, since the power required to operate it is present in the automobile engine. Cut- Outs 1 Test wk Plugs \ , 7 HEN an auto engine runs unevenly, the avera.e motorist short circuits the spark plugs successively with a screw- driver to locate the faulty cylinder. But if more than one misfires, the “‘shorting’’ of one plug at a time may not sufficiently slacken the rotation to locate the fault. G. C. Beck, of Spokane, Wash.; has devised wooden-handled wire levers that can be attached permanently to the spark plugs situated beneath the igni- tion wires. When all but one of thelevers are moved to bring the ends in contact with the iron shells, but one cylinder can fire. Mr. Beck says that if all cylinders are thus tested independently, the dead cylinders are certain to be discovered. AUTO DRYDOCK SPEEDS REPAIR WORK _ ACCOMPLISH greater speed in automobile repair work, as well as greater convenience for mechanics and motorists alike, a garage owner in Boston, Mass., has equipped his shop with an in- biles in need of repair enter the “‘drydock” from the street level, and run along the elevated tracks. In the repair shop they are elevated about three feet. genious automobile drydock built of steel channel beams. This innovation makes it possible for mechanics to~- make repairs—such as mending broken springs — beneath the body of the car without the use of jacks. The drydock is built of channel beams riveted and bolted to form a series of runways. The beams are spaced so that auto- mobile wheels will fit into the channels and run along them. The arrangement is such that automo- Channel beams form “‘drydock’’ and runway for automobiles vf get aut gra vel cra alv

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‘T to fur. faster certain ed and k-up,” g the forcing age at eds js impog- acuum e the ) per. /Omati- lve box > but. ee for- $s and eutral, ible to se acci- ce the n must before to put erse, atus, it be in- a few experi- nic on ing se- nission, no al- the or floor looring e from eration irse re- | a pol- » lubn- ‘acuum perate, te it is RK ydock” ng the yp they riles and Engines Balk T bie ’s a Sure-Fire Way to Keep Your Car Running Smoothly in Winter By F.A. Platte Instructor, Department of Physics, Columbia University INTER—frozen radiators and j balky engines. Nearly every motorist thinks of them to- gether. But why should the pleasure of automobile driving vanish with the mi- grating birds? Is there no sure-fire pre- ventive for the frozen radiator and the cracked water jacket? Can’t we count always on hearing the purr of the engine after a single push on the self-starter? For every car there is an effective way to avoid the most common of wintertime woes. First, let us consider the cooling system and its troubles. All freezing can be avoided if a proper mixture is main- tained in the radiator and its connections. There are many varieties of anti-freezing mixtures that can be bought or made. Some are effective, others injurious; but it is safe to say that denatured alcohol mixed with water is the most successful for general purposes. Find Lowest Winter Temperature Denatured alcohol will not freeze until the temperature falls to 200 degrees below zero. A mixture of water and alcohol will freeze at a temperature correspondingly higher, depending on the amount of water used. Find out how low the ther- mometer usually falls where you live; then consult the following table to deter- mine what ratio of alcohol to water you should use: Temper- Alcohol Water Specific - ature Gravity 18° F, : part 5 2/3 parts .9820 12° 3% -9740 0° i ig 3 -9625 % below 1 -9578 20° below - 1 i % -9475 Before filling, inspect the radi- ator and joints for leaks. Repair FROZEN HE NO CIRCULATION THROUGH PIPE ‘POPULAR SCIENCE MONTHLY When Radiators. Freeze _ these and find out how much liquid the system will hold. Fill up the radi- ator with water, then drain it off through the petcock at the bottom. Measure the drained water with a quart measure and remember the quantity as the figure to be used as long as you operate the car. The average content of radiator and water jacket is 35 quarts. This would require 15 quarts of alcohol in a locality where the lowest temperature is zero. Now close the petcock, pour denatured alcohol into the radiator and fill it up with water. Of course the mixture will not last indefinitely. The radiator should be inspected and filled every day just as in the summer. Some motorists mix water and alcohol in the original propor- tions and continue to fill with that mix- ture. This is wrong, for it will cause the radiator to contain nearly all water in a short time. This is due to the fact that 77 . The freezing breath of Winter holds no terror for the motorist who has prepared his automobile for the lowest temperatures alcohol boils away at a lower temperature than water, namely 171 degrees. If you find that you require the addition of a quart of liquid, it may be that most of the replacement must be alcohol. A sure method of making additions cor- rectly is to rely only on a hydrometer, an instrument that determines the specific gravity of liquids lighter than water. When inserted in the mixture of the radia- tor it will tell exactly the proportions of water and alcohol. In making readings, the temperature of the mixture should be about 60 degrees; otherwise the hydrom- eter will not register correctly. A method often satisfactorily employed is to make replacements with a mixture containing 75 per cent alcohol. In general, this will keep the alcohol content high enough. Wood alcohol should not be used. It is harmful to. the rubber and metal connec- tions and its fumes injure the eyes. aiceinemieeemeiia Vi ear st mea * casio ae x Grain alcohol is effective but too This diagram shows how to determine the proper mixture of al- cohol and “I wonder what’ can be the trouble?” asked the puzzled winter driver, as his engine balks and he sees steam coming from his radiator. Without warning, the water passing through the cooling coils of the radiator has frozen at the bottom, cutting off circulation in the cooling system. Meanwhile the heat from the engine boils the impounded water at the top of the radiator, as shown in the diagram water by means of the hydrometer (at ea... Tracing the lines from thermometer readings (at left) gives the correct hydrometer readings in specific gravity Seip nS Se ee EE He er eaten \ ne ony a RY A MT PTL Ty RR: enn —aaepnenrnae ~yer come general SONA Ail as pate Eo ERS APTI GE BE TIT set gt eet gees % een ee

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78 a ON rns ech GS he AA eat niamelinatie mnt s Nt ou oe ee expensive. All the alcohols give off offensive fumes when heated, but de- natured alcohol fumes are mild and non- injurious. In very cold climates it may be advis- able to use a half and half mixture of glycerin and denatured alcohol. Glycerin does not evaporate so easily as alcohol. Its disadvan- tage is that it is difficult to remove in the spring when changing back to water. Don’t Use Kerosene Kerosene sometimes is used as an anti-freeze liquid, but it is not satisfactory. When heated, it becomes dangerous. It boils away rapidly and gives off an offensive odor. Calcium chlorid will stop freezing, but it will also stop the car; for it eats away the solder and copper or aluminum in the radiators. Ordinary salt can be used in an emergency. In addition there are patented products on the market for stopping freezing. Many of these are good and will work as well as the denatured alcohol mixture recommended. Radiator covers will help also, by protecting the liquid from wintry blasts. If your radiator has been taken care of according to the directions given, the next consideration should be that of quick starting. Too often, when you turn on the ignition and step on the self starter, the engine fails to budge. What is wrong? The trouble usually is that cold gasoline vapor from the carbureter strikes the cold walls of the cylinders, condenses, and forms puddles on top of the piston. This liquid cannot explode. No matter how often you shoot a spark through the plug, your engine will remain dead. The easiest way to avoid this difficulty, of course, is to keep the car warm in a heated garage. POPULAR SCIENCE MONTHLY consisting of a small airtight tank holding about a quart of priming fluid. From this tank a pipe leads to the inlet manifold. Another pipe leads to a control pump on the dash. Operating the control injects a small amount of the priming az A few drops of petroleum ether, injected into the petcock of each cylinder with a priming gun, is an effective means of starting A primer with dash control provides an easy means of quick starting on a cold day fuel into the inlet manifold. From there it is sucked into the combustion chambers, firing at the first spark. Another method is to keep a smal] bottle of petroleum ether and a priming gun in your toolkit. When the engine refuses to respond, shoot a few drops into each cylinder through the petcocks near the spark plugs, or into the float chamber of the carbureter. You will be surprised at the effect. In tem- perate climates a mixture of half ether and half benzine will be found to work well. Ether Aids Starting Some motorists add _ three ounces of ether to every five gal- lons of gasoline in the tank. This will aid in obtaining proper vaporization for starting. To aid further in vaporization it is well to open the throttle when turning off the ignition in stop- ping the car. In this way the vapors will be drawn into the cylinders without burning, remaining there until you are ready to start again. Also cover up the hood of the car when you put it into the garage in the evening. Enough heat will be retained in the engine to prevent the cylinders and carbureter from becoming too cold. In spite of all of these precautions, trouble occasionally is encountered in starting, by reason of the fact that gaso- line will not pass through the carbureter. This usually is because a drop of water has frozen over the opening leading into the bow! of the carbureter. Even though the gasoline used may have contained no water, the cold bowl of the carbureter may condense enough water vapor from the air within to cause a drop to accumulate. Make an inspection for this trouble before you decide to tear the engine apart. Since warm gasoline will assist greatly in starting, But you cannot take the garage along when you go downtown and park your car at the curb. Undoubt- edly the simplest way to assure quick starting under all circumstances is to prime the engine with some fuel that is lighter, more volatile, and more easily fired than ordinary gasoline. Priming Fuels Among the satisfactory fuels is a high grade gas- oline such as used to be available as motor fuel in the days before refiners lowered the grade of gaso- line. This high-test fuel may be obtained from drug stores or from the large oil companies. Another prim- ing fluid that manufacturers have been producing in re- cent months is known as “petroleum ether,” differing little frgm high test gasoline. The easiest and most con- venient method of priming is to insta]l an equipment OUR Cylinder Valves—There are two valves for every cylinder; one to admit the ex- plosive mixture and the other to release the burned gases. Open- ing and closing are regulated by the action of cams attached to a shaft that conforms in its turning with that of the main shaft, with which it is connected through gears. As the cam turns, it raises and lowers a small piston called a “tappet.”” The vertical motion of this tappet is transferred to the stem of the valve, causing the latter to be raised from its seat when it should be open and lower- ing it when the port should be closed. A spring surrounding the stem serves to keep the valve stem pressed against the tappet during this movement. In order that the valve may seat properly, the tappet must be separated from the stem when in its lowest position. The amount of this air gap varies in different cars from the thickness VALVE UR VALVE DOWN many means have been re- sorted to in order to heat the carbureter. Electric heaters, reflectors or even electric irons have been used successfully to accomplish this result. Electric heaters are of tissue paper to one sixteenth inch. a CLEARANCE E’ , TAPPET available on the market to keep the carbureter and _ the manifold warm while the engine is idle, utilizing current from the battery. ARE your head- lights dangerous? Do you realize that a blinding glare in the eyes of the other fellow may bring a _ - catastrophe to you — and yours? In a remarkably usable article in next month’s issue Mr. Platte will tell how to .make simple adjust- ments to assure safety to yourself and others in night driving.

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three e gal- This roper To it is when stop- y the > the ining iain. when ning. ngine ireter tions, od in gaso- reter. or has o the th the d no * may he air ulate. oefore e will rting, en re- - heat ectric even 1 used nplish ; are arket r and while lizing ry. ead- ous? mata the ther goa you ably next Mr. w to fust- ifety ‘hers POPULAR SCIENCE MONTHLY New Inventions for Auto MMA MAW Equipped with a con- trol lever within easy reach of the driver’s fingers, this auto light dimmer has the ad- vantage that its me- chanical parts are inclosed in a_ steel housing. Installation requires no hole boring nor rearrangement of the lighting system A radiator cap that swings aside when the radiator is to be filled is said to be theftproof and to prevent jarring of the motometer. Turning a knob on one of the wings permits the cap to slide- up and swing to the side Operating the spotlight from within a closed car is possible with a new lamp inserted in the windshield and controlled by the driver by a pistol grip and trigger switch. The device is inserted in a hole bored in the glass and held firmly by broad metal flanges This folding automobile lamp can be placed in any position on the car where illumination is needed, and is attached by means of a ring and a U-shaped spring clamp at the base Crawling under the car is said to be un- necessary in operat- ing the jack shown above and at the right. Turning a Resiliency of pneumatic tires is claimed for this spring wheel designed for heavy, solid-tired trucks. Short leaf springs radiate from the hub thumbscrew at- taches the jack to wheel rim and hub The jack in operation. Its broad base is brought to rest on the ground simply by driving the car slowly forward or backward 79 Comfort Three numbered dial rings below the steer- ing wheel spider con- trol this new com- bination safety lock. Setting the combina- tidn with the rings locks and unlocks the steering post when a small lever is lifted A combination rear view mirror and parking light is an unusually useful auto attachment. Turn- ing the mirror to face downward automatically switches on the light at- tached to back of mirror. The switch is concealed in the bracket arm" —, SS Se . pers Se ee i ees aera ga DEES OE rae ee re are eer Serer ont eer - - - ee ee 2 Ne erg EE ATES TIENEN MX SOE Ae? pa Bart > Sota yee 2 rer Ailey ste ceed

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ath ea A NS 2 eee Sh IEC aSik Seles aaa apm TE oP es « aa 4 aj 4 ‘ : i] ad , ig ¢ + # ; z a 7 a 2 F Aad te a SAE RET Pie : pepe i POPULAR SCIENCE MONTHLY Handy Kinks for the Auto Owner , Y HENEVER spark plugs are car- ried loosely under the seat or in the toolchest, it is often found that the porcelains have been cracked. A safer and more convenient method is to carry the spare plugs on a rack fastened to the dash under the hood (Fig. 1). A wooden strip, bored with holes to receive the threaded ends of the spark plugs, is fastened with wood screws under a bent strip of sheet steel, which has slots to Pig. i. Holder for spark plugs Y¥ under hood receive the con- tact screws of the plugs. COMBI- NATION parking and trouble light, — easily made in _£043.01,uAMP CORD the home work- SEAT IMA shop, is shown in Fig. 2. A flange attached to the side of the body supports the tee extension of the lamp, which is held in place by a wing screw. The 1%-in. opening through the flange allows a 20-ft. length of lampcord to be passed in underneath the seat with- out lifting the cushion. A switch may be installed integrally with the lamp or a separate switch may be placed on the dash. 1/// ENDER Fig. 2. Trouble light fy SPRING 77 SHEET BRAS 4 Fig. 3. Clip for cup A SPRING clip fastened to the grease 44% cup as shown in Fig. 3, will prevent the cap from becoming unscrewed and falling off. The clip is held in place by the stem of the cup. | poaeaerme of a tail lamp to light is sometimes caused by a short circuit in the ground circuit when the frame of the car is used as the ground. This is more apt to happen when the lamp is mounted on the tire carrier. Running a wire from the lamp bolt back to the frame of the car will show whether this is the trouble. HE ignition locks on automobiles seldom are designed to make the car completely thiefproof. Knowing the con- struction of the various types of ignition locks, criminal mechanics readily ‘find means to wire around them and start the car without the aid of a key. However, by inserting a secret breaker in the circuit, as shown in Fig. 4, it is an easy matter to outwit the thieves. One of the wires from the battery is led to a car is parked, it is necessary only to take out this plate to break the circuit. F THE fins of a tubular radiator are badly bent, they can easily be made even and straight by using the tool shown in Fig. 6. This is a sheet of steel plate, doubled over at the center so as to leave the edges about 1/16 in. apart. Thetoolshould beabout12in.long. When fins have been broken out, they can be re- WIRES To BATTERY METAL PLATE Fig. 4. Theft switch Pig. 7: Bracket useful for testing spark plugs WIDTH TO SUIT SPARK PLUG — S rN Efi en Fig. 5. When stuck in a mud hole, a machine can be raised to solid ground by fastening a short length of wood or heavy pipe to the rear wheels is SPACE SHEET STEEL OS DOUBLED OVER MISSING FINS REPLACED WITH THIN SHEET METAL STRIPS’ Fig. 6. Straightening and repairing radiator fins screw in the jamb of one of the doors before passing to the general system. A second screw is situated about an inch from the first one and is connected with the wire leading out. A small notch is made in the wood slightly above the upper screw to hold the hooked end of a small metal plate. Closing the door holds the plate firmly against the heads of the two screws and the circuit is closed. When the placed by thin sheets -of brass soldered in place and straightened. fins have been alined, the radiator can be given almost the appearance of a new one by painting it with a coat of black paint diluted with turpen- tine. F°® testing spark plugs rapidly and without danger of being shocked the holder shown in Fig. 7 has been found satisfac- tory. It is simply a piece of steel or brass with a hole drilled in one end and a slot in the other end large enough to fit the plug thread. The bracket is held under a cylinder head bolt in such a position that all leads will readily reach a plug held in it. ‘ / SOLDER SPOUT TO CAP BREATHER,» Fig. 9. Oil spout APERED cotter-pins in pump-shafts, generator couplings, and in the engine of an automobile are frequently located where a hammer or other tool cannot be placed so as to permit of driving them from below. Many times the mechanic will drive them from above and they will fall into the engine pan. Figure 8 shows a quicker method of removing such pins. i ies detachable oil spout shown in Fig. 9 is made of a small piece of tin soldered to an extra oilcan cap from which the top has been cut. The spout is used for pouring oil without waste into the breather tube of an auto. After all the ¢ a c I t V ¢ f ] 1 I } i i re ee a

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’ are nade tool steel as to part. Vhen e€ re- icket ul for ting ark ugs thin rass in nd led. . the een the n be ost ance e by with lack ited en- ing lugs ind ager the nin een fac- iece rass ole ther ead. ider 2ads afts, gine ated t be hem anic will OWS ins. . in T tin rom out into

The POPULAR SCIENCE MONTHLY 81

Home Workshop Arthur Wakeling, Editor

Sewing Cabinets Home Craftsmen Can Build tive Priscilla sewing cabinet, which costs little for materials and re- quires no elaborate joinery, is an ideal piece of furniture for construction in the home workshop. If you have a place in your home for such a cabinet—and in most homes a corner of the living-room, if not a special room is set aside for sewing—it will well repay you to build one. Don’t let the turned pogts and stretcher deter you, because if you have no access to a lathe, you can have them turned quite reasonably at any car- penter shop where there is a lathe, or at one of the small woodturning shops to be found in all cities and many towns. Many requests have been re- ceived from readers for a magazine article or a blueprint on a Priscilla or, as it is sometimes called, a Betsy Ross sewing cabinet; and the general interest among home workers in this type of project is in- dicated by the fact that the now Te especially dainty and attrac- famous Home Workshop Blueprint . Mi is No. 1, a sewing table, issued exactly two years ago, is still in great de- mand and hundreds of copies are being sold. It is true that Priscilla cabinets can be purchased for small sums in department and furniture stores, but there is no comparison between the average cheap commercial cab- inet and one made by hand from genuine selected walnut or mahog- any along lines as structurally and TRAY Ya 4 Ya" 10%

POST 19%"x 154" An alternative design for a modern sewing cabinet, which does not require any turnings artistically sound as this cabinet. Com- mercial cabinets, unless of the best qual- ity, will deteriorate with age; this cabinet, if built and finished properly, will actually

improve and gain with passing years the richness and beauty of surface that dis- tinguish fine heirlooms and antiques. As an additional aid for those who wish to build the cabinet, a blueprint (No. 31 in the Home Workshop series) with full size details has been prepared and can be obtained for the nominal charge of 25 cents to cover the cost of blueprinting, handling, and mailing.

This useful and beautiful Priscilla cabinet in genuine mahogany or walnut will grace any sewing room So little material is required that it will pay to use walnut or mahogany. The case itself requires stock about 7/16 in. thick. A board or two should be obtained sufficient to cut the two sides 10 by 1434 in., the two ends, 1114 by 18 in., the two lids 53% by 16 in., anda strip for the top center 2 by 16in. The posts or standards require 2 pieces 134 by 134 by 10% in., either solid or glued up from %-in. stock, and the stretcher requires a piece 114 by 14% by 14 in. Each pair of feet is cut from one piece of %-in. stock 4 by 8 in., and the handle requires a piece 7% by 134 by 101% in. The rest of the stock need be only 4 in. thick. The bottom of the case is 6 by

le" 578 << PO GIO I~ md) Vv. ‘2 p BOTTOM OF-TRAY 74 Xo"x 92" \ sv | 7 ayy! 3 posts 7s, Dy A. STRETCHER Va" DIA. HINGED COVER

Construction of Priscilla sewing rd box with main dimensions and details of the important joints : 1434 in.; the bottom of the tray, 6 by 9% in. The sides of the tray are 114 by 103 in.; the ends of the tray, 1144 by 54% in. The long divi- sion in the tray is 114 by 9 in.; the center division 1144 by 5% in., and the tray rests or slides are 4% by 14144 in. To reinforce the bottom, 2 pieces 34 by % by 1414 in. are fastened underneath the long edges. Besides these parts of wood, four brass 1 by 1 in. hinges, as well as nails, screws, dowels, and glue are required. Note the tongue-and-groove construc- tion of the case joints, between both the sides and the ends and between the ends and the bottom. The stretcher is tenoned into the posts, and the feet are attached to them with dowels. If for any reason turnings cannot be obtained easily, the modern sewing cabinet illustrated in the left-hand col- umn is an excellent alternative design. The essential dimensions and details are (Continued on page 122) ee

ian ee ie NE aay ne

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et ove Siete he aS SERIO NE Ey Reins i plement oe AS sig tee sittin. ee - / EA TRAAMY 5 ae DA REAEEAEE O Yee ASRS Paid wy ee is es Sa sepatoerises tit Fy aR Saati i BA HO ARN NR 2 cs Rs « i ~~) eats wt 7. pater om = HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Didieue Ski Sleds Provide Healthful Sport \ N THEN you're pilot of this chummy tandem scooter (Fig. 1) and the other rider swings up behind after pushing off, you can be sure of a speedy joy ride, right side up. If good staves are not available, ski material must be steamed (see Howard Greene’s article on skis in last December’s POPULAR SCIENCE MONTHLY) and, when partly cooled, wired to posts, as shown. The front post is shaped from a 38-in. length of 2 by 3 in. stock, 31 in. of which is rounded off to 2-in. diameter. Cut the rear post 9 in. long, and square one end for a distance of 2 in. To each post, center and fasten a shoe with finishing nails sunk into the bottom. A mending plate is riveted beneath the toe and heel of each shoe, the end holes being left free for the wire. For stringing a shoe, 7 ft. of wire is needed. It is passed through screweyes set 1 in. below the shoul- der of the posts, as indicated. The runningboard is 5 by 38 in. Center one post hole 3 in. from the front end and make a slot 4 in. long in the other end for suspending the rear post. Before inserting the long screw pivots, round off the shoulders of the rear post so that it can swing backward and forward. The seat framework is built of 2-in, wide strips. Cut the middle upright 22 in. long and center to the runningboard with a corner iron 17 in. from the front. Cut the rear strip 25 in. long and hinge one end to the top of the post as shown. Two more strips 24 in. long form the foundation for the front seat. One can be 2 in. longer, if desired, to make a rung for supporting a horn. The seat board is 7 in. wide and 20 in. long, the seat proper being approximately 7 in. square and the remainder being trimmed to 4 in. wide. Center a hole for the front post 2 in. from the front end. The rear seat board is 23 in. long, with a square seat. The forward part is 5 in. wide. It is fastened to the upright 16 in. above the runningboard with a long screw 3 ex" 5 uDER wf 4 _—_— x At Fig. 2. The ski coaster, which is built easily and cheaply because the double-end runners can be sprung into shape without steaming at each side. The hand grip is a 12-in. length of broomstick secured in holes cen- tered 11% in. from the ends of the strips supporting the front seat. For steering aids, split a 2 by 3 in. piece into two 12-in. lengths, 114 in. wide. For the foot-piece bend 14 in. of the ends of a 6-in. strap-hinge clip as shown, and insert a wedge between the parts, securing it with a nail through each middle screw hole. Fig. 1. the details. BOARD FOR BENDING LEDGE HINGE By Roland B. Cutler The handle-bar is 14 in. long, clipped at the top of the post with a 4-in. strap hinge. Under the end of the front seat construction, 4%¢-in. hardwood plugs or dowels key the post to the frame. Bore the holes for them at quarter points around the post and allow the plugs to extend 1 in. to support the three seat members. The list of materials for the scooter is as follows: 2 wide barrel staves, or 1 board % by 7 in. by 10 ski material of similar ft size 6 ft. of 2 by 3 in. studding 1 light strap hinge, 4 in. 1 light strap hinge, 6 in. 1 corner iron, 4 in, 1 hinge butt, 2 in. 4 mending plates, 4in. 4 screweyes, 1% in. 1 doz. screws, No. 12, 244 in. 2 doz. screws, No. 7, 1 in. 8 rivets, No. 9 14 ft. soft galvanized wire, No. 12 The light, springy coaster (Fig. 2) is geared up to ski speed and will shift into “high” at one push of a toe accel- erator. Although only 5 ft. long, it will not limp under any overload, for it’s built for business as well as speed. The hardwood stock required is as follows: 2 shoes, each % by 3 by 66 in. 2 ledge pieces % by 3 by 66 in. _ 16-ft. length of flooring, 3 by in, 2 beams, each 1 by 4 by 15 in. 4 posts, each 1 by 2% by 7 in. The hardware necessary 1s: 4 light strap hinges, 5 in. 8 light T-hinges, 3 in. 16 stove bolts, 3/16 in. by 1 in. 5 doz. screws, No. 6, 1 in. 26 ft. galvanized wire, No. 12 4 corner braces, 4 in. 8 mending plates, 3 in. ¥ doz. screweyes, 1 4in. 1 doz. screws, No. 8, 1}4 in. Shoulder each end of the beam 114 by 3 in. long and fit the shoulders into 1 %-in. deep mortises in the posts. Fasten posts and beams together with screws at each side, as shown in the left-hand detail. Under each beam place two 4-in. corner braees. To the lower end of each post attach the flap of two 3-in. T-hinges. Note the screweye inserted through one hinge for wiring. The tandem scooter completely assembled and some of Note how the rear shoe is pivoted to runningboard Nail the ledge pieces over the shoulders, centering each post 15 in. from an end. Set this frame on the shoes and locate the end holes in the hinges for wiring. These wire holes are centered in the shoe about 2 in. apart. Midway be- tween the posts, make two pair of holes 6 in. apart, and in the ledge, center one wire-hole above each pair. Loop 13 ft. of wire, with equal ends, through a screweye at one end and then wire as shown, keep- ing the ledge and shoe parallel. Tap all bends in the wire to fit snugly, and cut into the edge of the ledge for the wire to pass. Secure this wiring in the opposite screweye. A 5-in. strap hinge connects the end of each ledge and shoe. A stove bolt is passed through the end hole of each strap, and a 3-in. mend- ing plate is used in place of a washer on the inside. Trim the shoes to about 4 in. thickness and bolt the hinges only to them. To bend and to hinge the ledge, use a thick piece of beard, as shown at the right. Notice the large hole in which the end of the hinge flap must rest, flush with the under side. Bolt the end of the ledge to one of the hinge screw holes. With this ‘“‘squeezer’” drawn over the ledge, the end hole of the flap can be located, and the fastening made as to the shoe. Thé middle seat -boards are 50 in. long, and the side boards are 40 in. long. Special Line Holder Aids in Fishing through the Ice a a all raenute pi G r A A So i If an old chair cannot be found, this holder can be made easily from other material HOSE who have tried the ordinary and not entirely satisfactory ways of holding the line in ice fishing, will find use- ful the line holder illustrated. To make one like it, hunt up a dis- carded chair and cut off a length of one of the turned legs, as shown, leaving parts of two spindles connected with it. A sharp point for the holder is provided by inserting a nail, about 2% in. of which is allowed to protrude. File the head end to a sharp point and provide a ferrule, if possible. When ice fishing, let down your line to the right depth and jab the spike into the ice. When your bobber begins to dip, signaling a bite below, the holder can be instantly seized.— ROBERT PAGE LINCOLN. es IE ALOE EI

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C rs, id. te ig. he ye- les ne ual ne ep- ige his the ond nd- her ; to the ige, own urge inge ider e to Vith the can 1ade seat ards

Ider rial inary ays of d use- a dis- one of arts of »vided in. of le the vide a line to ito the o dip, can be NCOLN.

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 83 Saving Money in Building a Small House By R. J. Stephens N building a home, few of us plan far ] enough ahead. We find later that we should have had a breakfast room, more attic space, or something equally expensive or perhaps impossible to add. If you are short of funds when you build or buy your home—and who is not?—plan so that you can add to the house without detracting from its grace- ful lines and without giving the additions the appearance of an afterthought. If you are thinking of building this spring, start at once to make as complete plans as possible. It would be folly to suggest one ideal type of a small house; yet, countless as are the excellent plans furnished by various agencies in the building industry, many prospective home builders are unable to decide on just what they want, or, having decided, eventually find a lot of changes they would like to have made. As regards the small house, it goes without saying that the two-story type is the most economical. It doubles the floor space on the same foundation and under the same roof. It is better to have fewer rooms and at least one large living-room in which to “‘live’’ and receive your guests than to cut up a house into little rooms or cells, as indicated by the two typical plans below. A large living-room can be acombination living-room, — where wheelbarrow trestlework would otherwise have to be built around the forms. On a level lot the idea works even to better advantage. The idea is not to haul the mixture after mixing, but to arrange so that the concrete can roll right off the mixing board into the forms practically by gravity. For foundation work, I have found it sufficient to turn the dry mixture only once and then to apply plenty of water.

TARRED FELT

SCREEN FRAME. OUTSIDE CASING

dining-room, and even

Fig. 2. Above:

bedroom.

Every time you add a partition, you have added four corners to your floor space, which are good for nothing except to set a piece of furniture in; at the same time you have

Five building suggestions that are simpler than the standard con- struction. Fig. 3. At left: An un- usually easy way of making porch piers and frame

cut off air and light, added further expense, and in some instances made the house more difficult to heat uniformly. Cheap as is a concrete foundation, it can be made cheaper by a little common sense in building it. Concrete work is hard and yet I have seen many men mixing their material far away from their forms, hauling the extra weight of water, “ slopping it all over, losing lots of it, and

= A BEDROOM i 2 is«K x =e DRESSING Oo fh ~ ROOM : am, 4 ae BREAKFAST ALCOVE ~s. LivingRooM = —_ \

Fig. 4. Typical bungalow plans, the one at the left having all the advantages handling it twice instead of once. Build the mixing board, if possible, so that it is lipped over the edge of the forms (Fig. 5). This practically cuts the labor of mixing and pouring in half. The illustration shows the method used where there is a high exposed wall and

In Fig. 3 is shown an easy method of constructing porch foundations and frame- work without wasting any time making unnecessary calculations. Cut the four outside joists according to the length and width of the porch and nail them all . square and level with the aid of two temporary 2 by 4 in. supports. Nail braces across the corners to hold the frame square and then construct the forms for the piers from 8, 10, or 12 in. boards at the outside corners. A few nails set at random inside the joists at the corners will help: strengthen the work when the concrete is poured. You will see, also, that the joists rest on square shoulders of the piers, which is excellent construc- tion. A small house that is to be set on a foundation of piers can be laid out in the same way. Wide drop siding, which is quite popu- lar in many parts of the country, can be imitated at a considerable saving, as shown in Fig. 2, by using ordinary ship- lap, one’ of the cheapest varieties of lumber. Being much heavier than regular drop siding or clapboards, it can be applied over good tarred felt directly to the studs and does away with the neces- sity for using sheathing, when the building code allows. This is a substantial saving in both time and material and yet makes a house warm enough for any moderate 4

climate. In such construction it is, of course, necessary to set the door and window frames before applying the siding. The casings should be shimmed out with lath so that the ends of the siding will not project beyond them. The simple construction of garage doors shown in Fig. 2 involves mak- ing only simple saw cuts. If the joints are close and put together with screws, such a door will need no braces to prevent its sag- ging. The sash used in this door is the reg- ular 32 by 32 in. sash sal- vaged from government cantonments and _ usually obtainable at second-hand lumber com- panies for about $1.25 each. Note also the use of common barn door hinges, which can be purchased for about 10 or 15 cents each. If hinges are selected that will open back to 90 degrees, one leaf can be placed on the inside of the door jamb, thereby making the hinge look like a regular garage door hinge. This type of door is illustrated in Fig. 1. In an article published in the January, 1923, POPULAR SCIENCE MONTHLY about my home, I showed a proposed extension of a porch and this photograph indicates how the extension was finally completed with a garage below. By opening a base- ment window, the garage can be heated sufficiently in winter. The porch above the garage is finished in pergola effect, which makes it cooler in summer and does not shut out the sunshine in the winter from the triple window that opens on it. The ease with which this addition was made was due purely to foresight in planning. An easy method for building porch and stair railings is shown in Fig. 2. Prac-

and garage addition

Fig. 5. Labor and often scaffolding can be saved by this method of mixing concrete tically no nails are exposed and there are no places to catch and hold the moisture. The 1 by 3 in. strips are first nailed to the spindles, and afterward the strips are nailed to the 2 by 4 in. bottom rail and the 2 by 6 in. top rail. Since such (Continued on page 139)

Ses aay a ares

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84 HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Making Your Loudspeaker Talk Up An Easily Constructed Two-Stage Amplifier that Can Be Added to Any Ordinary Radio Detector O SINGLE piece of radio appara- tus, with the exception of a de- tector unit, is of greater value to both listener-in and experimenter than a two-stage audio-frequency amplifier unit. By adding such a unit to a standard detector circuit, the strength of the in coming signals can be built up to a point where a loudspeaker can be operated with sufficient volume to fill a large room and, under favorable conditions, an entire house. It is then no longer necessary to distribute a pair of phones to each person until the assemblage takes on the aspect of a convention of telephone operators. Distant stations usually come in best on earphones when a single stage of audio- 8 frequency amplification is used with a detector unit. When a good aerial is used, two stages of audio-fre- quency amplification added to a detector circuit will bring in on a loudspeaker, loudly and clearly, stations 500 and more miles away. The two-stage unit enables the experi- menter to add amplification to any of the various types of detector circuits he wishes to try out without the necessity of incor- porating two stages in each set. If care is exercised in the construction, no difficulty will be experienced in its operation. Most of the trouble in ampli- fier circuits is usually due to the use of faulty parts, not properly tested before being placed in the circuit; to the incor- rect location of parts and wiring, or to slipshod methods of construction. Standard Circuit Is Used Before attempting to build the unit, read over carefully Jack Binns’ article on troubles and their prevention, appearing elsewhere in this issue. m< oe — soe nd eo ' The circuit used in this unit is the standard, tried and tested audio-fre- queney amplifier circuit shown in the wiring diagram. A 7 by 10 in. panel was used for this unit, but if you can spare the space, a7 by 12 in. panel will make it easier to construct and perhaps give slightly better results. A standard transformer coupling is used, the first stage being coupled to the detector circuit with a high-ratio audio- frequency transformer, while the second stage is coupled to the first stage with a standard amplifying transformer of low ratio. The ratio of the first transformer, C, may run as high as 10 to one, but that of the second transformer, J, should not be higher than about five to one. Two low-ratio transformers can be used, but two high ones are not advised. The trans- formers should be mounted so that they are at right angles to each other. Placing them at opposite corners will separate them interaction between circuits. Separate rheostats are used for each as much as possible and reduce By Joseph Calcaterra of POPULAR SCIENCE MONTHLY’S Radio Staff tube, this arrangement being more desir- able than that in which one rheostat con- trols both tubes. The type of rheostats and tube sockets used will depend on the type of tubes used in the unit. D is a .001-mfd. fixed condenser. Three double- circuit jacks are used, the first, H, is for Without tubes and batteries 1 ~ 2oee = ouaiaN om) - | JQ 4 ° {Vv eee

if ° | | : Ea | this ampli | | | fier costs a ak | an aed | about $15 Q jo PR iS iT 1 ,jasart] _ | | +] | UULE ke —— as “Ca . y —¥)1)1)0{a\0)0 1448} — BATT +

Wiring dia- gram of the two - stage unit (above) and views of the front and rear of the panel (at right). The letters on the large photograph correspond with those on the wir- ing diagram the the the plate circuit of the detector stage; second, G, is for the first stage, and third, L, is for the second stage. This is the best arrangement when the unit is to be used with a detector circuit that has no jack. If your detector has a single-circuit jack, substitute a double- circuit jack, eliminating the necessity of using jack # in the amplifier unit. Should not use jack E, the P terminal of transformer C is connected with binding post A, and the B terminal of the same transformer is connected with binding post B. Two posts should be added to the de- tector unit, opposite posts A and B of the amplifier unit. The top post of the de- tector unit, opposite post A of the ampli- fier unit, should be connected with the inside spring of the detector jack that makes contact with the outside spring connected with the plate terminal of the detector tube. The bottom post of the detector unit, opposite post B of the am- plifier unit, should be connected with the you

inside spring of the detector jack that makes contact with the outside spring connected with the B battery. The fixed condenser, D, is left as con- nected between post A and the positive of the A battery. Since the negative of the B battery is automatically connected with the fila ment circuit through its connection with the filament circuit in the detector unit, no connection for the negative of the B battery is provided in the amplifier unit. This is to eliminate any possibility of shorting the A battery. If, for instance, the negative of the B battery were con- nected with the negative of the A battery in the detector unit, connecting the nega- tive of the B battery with the positive of the A battery in the amplifier circuit would short circuit the A battery. The same type of tubes used in the de- tector circuit should be used in the ampli- fier circuit; use 11)4-volt, 3-volt, or 6-volt tubes throughout, or special circuit arrangements will be found necessary. This unit can be used with the detector unit described last month, if the same type of sockets, rheostats, and tubes are substituted. lt would be advisable, however, for greater convenience in connecting the two, to change the battery connections of the detector unit to the back of the set and place the phone postsso that they are opposite the input terminals of the am- plifier unit. Posts M and N are used to enable you to connect a loud- speaker or additional ampli- fier with the unit. A general idea of th method used in routing th connecting wires for greatest efficiency can be gained by studying the photograph of the unit. Since the parts and terminals in the diagram correspond with the same markings in the photograph, the beginner can follow the wiring of the unit without trouble and gain experience in reading wiring diagrams. How to Use the Unit No trouble will be experienced in wiring the unit if the connections are made ac- cording to the following directions: First connect the top spring of jack F with post A. Then connect the inside spring, which makes contact with the top spring, with the P terminal of transformer C. The bottom outside spring of jack FE is connected with post B, while the inside spring, which makes contact with the bot- tom spring, is connected with the B ter- minal of the transformer. A wire is next used to connect terminal F, of socket F with post O and another (Continued on page 110) e

fir

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led that pring » CON- sitive ery is . fila- _ with unit, the B unit. ity of tance, 2 ¢on- attery nega- ive of -ircuit 1e de- am pli- -Volt, tubes ircuit found d with eribed e type and It wever, ace in ehange ons of e back phone posite he am- ised to a loud- ampli- yf the ng the reatest ing the e parts espond graph, of the erience wiring ade ac- jack E inside the top sformer jack E 2 inside he bot- . B ter- srminal another

POPULAR SCIENCE MONTHLY 85

Be < oN Se ee =, as |

Book on Wood Finishing _—

y Ee A ul th { ; bias ) 1

Our book gives complete instructions for finishing all wood—hard or soft—old or new. Tells how inexpensive soft woods may be finished so they are as beauti- ful and artistic as hard wood. Explains just what materials to use and how to apply them. This book is the work of experts—beautifully illustrated in color— gives covering capacities—includes color charts, etc. Fill out and mail coupon

below for a FREE copy. JOHNSON’S Johnson’s Wood Dye has many uses, for both the artisan and amateur. Architects and contractors specify it for coloring woodwork and flooring in new buildings. Painters and decorators, use it with equal Satisfaction on new and old woodwork of all kinds. Housewives delight in it for doing over old furniture and for coloring reed and wicker baskets, etc. Manual training teachers and pupils use it for finishing their models. Upholsterers, furniture repairers and cabinet makers find it “just the thing” for their work— old and new. S. ©. JOHNSON & SON, Racine, Wis., U. S. A. (CANADIAN FACTORY—BRANTFORD) “<The Wood Finishing Authorities’’ WOOD DYE Johnson’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. Made in fourteen popular shades all of which may be easily lightened, darkened or in- termixed. Full directions on every label. a | S.C. JOHNSON & SON, Dept. P. S. 2, Racine, Wis. € “‘The Wooe Finishing Authorities’’ est paid, your Instruction Book on veautifying. E Please send me free Wood Finishing and HH) »» ] MY DEALER IS ] MY NAME % ADDRESS. ry City Ge States isco

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6 POPULAR SCIENCE MONTHLY

How Expert Mechanics Save

SP AMAMAY

Secrets of Success in Handling Taps and Dies HAT’S the matter over here, / Bill?” called Tom at the No. 9 tapping machine. “I’ve just broken another tap—the third this morn- ing—and I don’t know what is causing 1 Pada Old Bill machine and crossed over to where Tom was gazing perplexedly at a handful of broken taps. Just a glance gave Bill the solution. The work holder had slipped a trifle out of alinement, not enough to be obvious, but, nevertheless, sufficiently to make the tap run to side and break. When the work holder was again located centrally with the tap, all trouble on No. 9 ceased. shut down his one Just as Tom, a pretty thoroughly experienced mechanic, was confronted with a tapping problem he could not solve, so many of us go about our work wondering why taps break, dies are ruined, and threads are torn. A few of Bill’s suggestions to his fellow workers eliminated much of the tapping trouble in the shop where he worked. “Not half of the so-called mechanics know how to lubricate a tapping job,”’ was 3ill’s criticism at one time. Most men use common machine oil for all hand tapping. On steel and boiler plate one should use a mixture of lard oil and white lead of the consistency of thin cream. It is well to have a can of this lubricant on hand at all times. Cast iron and brass are best tapped dry. Whenever a lubricant is absolutely necessary with these metals, kerosene is the best to use. Lard oil, sperm oil, \

| \ s Ss Ss 4, s 2 3 a Ss Es CIRCLEY —Y

COUNTERSINK ? ROOT DIA Layout for a die, the first holes drilled and large detail of the top and bottom chamfers diameters must be maintained. A reduc- tion of the amount of metal removed makes the threading operation much lighter at a very small sacrifice of the strength of the thread. In fact, a die and (Continued on page 98) i]

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\ / rad- raw ard- igh- the ired - die ‘ool, ly a tal. laim and. able tool line=- pro- arge ‘umM- tools Lipu- d of and with is to izon- irate one- “eads > tap light ) and their in be f ac- float 0 the ee oe ; rear rtain by a n the read, 1 hole | ZA and fers MFER CESS reduc- moved much If your work calls for a Tap Wrench, be sure you pick up a Starrett No. 93 or the larger 93C. Both offer several ad- vantages in general tap and die work. The body is cen- tered enabling the workman to use it on lathe centers or upright drilling machines to start the tap straight. The jaws and knurled clamping nut are heat-treated. Write today for the free Starrett Catalog listing and describing more than 2200 fine tools. Ask for No. 22-"W." POPULAR SCIENCE MONTHLY 87 Charles — “What’s the print allow you, Bill?” *“Two thousandths under — nothing over.” “With no chance to fit and try and a fine chance of getting fired if you spoilit. AllI got to say is its a good thing you own a set of Starrett *‘Mikes’.”’ THE L. S. STARRETT CO, The World's Greatest Toolmakers—Manufacturers of Hacksaws Unexcelled ATHOL, MASS. Em Vr" 226444465455 445 O22 2448 22 O ee eee oe we eee Ly ad bh bd bb bbb BA Ad ddddeh ds, of the ie and

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88 BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY Shortcuts for Men Who Work with Tools IPE-FITTERS and _ repair men usually carry their tools about in portable toolboxes of open design. While an old box rigged up with a leather strap for a handle will answer the purpose, the one shown in Fig. 1 is neater and will prove handier. The slanting sides elimi- nate the dark corners where small tools have a tendency to hide themselves. The legs raise the box out of the litter too often found on the floors and elevate the tools to a height where they can be conveniently reached. A HANDY adjustable support that . will find many uses around the shop is shown in Fig. 2. old materials, the screw It is made entirely of com- ing from a dis- carded piano stool. The pipe is cut to the de- sired length and fitted with a flange at end. The pipe is then drilled at the other end with several holes to anchor the babbitt. The screw is babbitted in place. By rais- ing a burr on the thread with one Bar support a chisel, the . Cc screw will cut LATHE DOG into the bab- bitt enough to make it turn freely. The pipe should warmed at end before bab- bitting, to pre- vent its blowing ay | out before cool- ies ~ a ing. A V-block Fig. 3. Holding rod rigidly is fitted to end of the b =] one one piano-stool screw as shown. T IS almost impossible to cut a heavy thread with a hand die by holding the work in an ordinary vise, as the rod will turn in the jaws. By fastening an ordi- nary lathe dog to the work, as shown in Fig. 3, and allowing it to bear against the side of the vise, no difficulty will be en- countered in holding the work rigidly. lathe dog for A made from a dis- carded pulley by elongating the bore as shown in Fig. 4 and securing a drive pin to one of the spokes. The dog is equal to, if not better than, the common type, as the pulley rim prevents the lathe operator’s clothes from catching in the driving lug. Moreover the dog is better balanced than the type ordinarily used. SATISFACTORY light work can be "T°HE drilling attachment shown in Fig. 5, was devised for drilling between the flanges of an I-beam where the usual ratchet wrench was too long to permit of its use. There are many places where such a drill will work to advantage. norrrTrnrmnm orrrna sea ee ee es A square bar of steel is drilled to ac- commodate the drill and fitte’ ith a set- screw to clamp it fast. The epposite end is tapped to receive a pointed setscrew with which pressure is exerted on the drill. An open-end wrench is used to turn the drill. The same fixture can be used to tap the holes after drilling. “eas the purpose of assembling quickly a large number of cap screws, the special screwdriver bit shown in Fig. 6 of = Fig. 4. Safety lathe dog Fig. 5. For drilling TO BE FILLED CAVITY Sia Babbitting a worn-out bronze bushing Fig. 8. was designed. A split collar engages the head of the cap screw and prevents the blade from sliding sideways. The ends of the collar clamp the screw and permit of inserting it in the screwdriver bit previous to threading it in the hole. The screwed connection allows the collar to be removed when it is necessary to grind the edges of the blade. A locknut prevents the collar from working loose. FFSET socket wrenches can be made to operate more easily by adding a bent handle as shown in Fig. 7. A tubular section of brass or iron, from 18 to 20 in. long, is bent into the proper shape to form a crank and one end is riveted to the wrench. A door knob-or other knob is attached to the other end. © eatin riage bronze bushings ca readily be redeemed by relining the interior with a good grade of Babbitt metal. The worn bushing is chucked i1 lathe and bored to 1 in. larger than t} shaft. The bore should be rough and t} size is not important. This bore is thi tinned by using solder and soldering pas heated with a blowtorch. After it has been tinned, stand it up right on a metal plate and place in its ce ter a piece of smooth steel a trifle smalle: than the shaft, as shown in Fig. 8. Clamp the steel piece upright and center thi bushing. Then heat the bushing with the blowtorch and drop pieces of Babbitt metal into the cavity. The metal w melt and up iY cooling, the ae babbitt and bronze will lb: knitted by thi tinned surfac When co knock ‘+ ft mandrel, chu the bushing a lathe, and ream to proper size. LOCKNUT Nw THREADED NDIRECT daylight car often be utilized in dingy rooms to improve working condi- tions for drafts- men or mechan- —— SCREW-DRIVER Fig. 6. Screwdriver bit TUBES ics who have to pin depend — upor their eyes a great deal. This Scuet yas accom- WRENCH plished by on¢ engineering company by s vering 15-i1 wide strips ol plate glass and placing them or the window sills so as to reflect daylight against the ceiling, which was enameled white. The walls were repainted a lighte color and the improvement was such that artificial lights were greater part of the day. RIVETS’ Fig. 7. Wrench handle unnecessary the A N OPENING die can be used it 4 emergency to clear the burrs off the damaged threads on hardened or semi- hardened shafts. An ordinary die will no! do the work because it is difficult to start it, but by placing the open die over thi end, closing it on the good threads, a then backing it off, the damaged threads ean be cleaned. OR removing broken studs and bolts, special tool can be made from a left- hand twist drill, ground to a taper to giv the sides a small amount of clearance The end is cut square and then annealed rehardened, and drawn until it has be come a light blue. Drill a hole into the broken stud larg enough to allow the tool to be started ani then run it in with a tap wrench until i takes a grip.

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is Ss )6Ca lining abbitt od in an tl nd the s the r past it up- ts cer smaller Clamp er the ith the Sabbitt al wil 1 up BR, the t and vill be by the urfac« cool, t chuck ling » and proper rect tht can utilized rooms rove condi- drafts- 1echan- have to upon yes al. This cc on- by one -ering v by sil- 15-i1 rips of ass and them or laylight rameled i lighter ich that ry the od ina 3 off th yr semi- will not to start yver the ids, and threads bolts, é n a left: r to giv’ earance nnealed has be: ud larg rted ani . until 1 POPULAR SCIENCE MONTHLY 89 *T HZ AIR 15 Ut bk. OFF SEEING Ss Y O-U Sree) A oN “| ieee _~ ~ 2S AL TY Eww “en , Eveready ‘Three’ arene 414 volts, three distinct uses. Length, 4 in.: width,1 3% in eight, 3 in.; weight, 140 At all reliable radio deale rs is ‘“C” Battery isa Wonder Worker OU can make the loud speaker re- tions on the label and in ‘How to Get the spond with a new fullness and Most Out of Your ‘B’ Battery,” a booklet naturalness of tone. You can save money. on “B” and “C” Batteries, sent free on by adding months to the life of your “B” request. 3atteries. These things you can do by This triple-use battery can also be using the new Eveready “Three” as a “‘C’”? used as an ‘“‘A”’ Battery in portable sets. Battery. Light and full of pep. Its third use is as a You already have an “A” Battery for ‘‘B” Battery booster. the filament and a “B” Battery for the Use the Eveready ““Three’’—a tested plate. A “C” Battery is connected to the product of the world’s leading electro- third element of your vacuum tube, the chemical battery laboratory. It serve grid, affording a control that is marvelous more radio uses and effects more econo- in action on audio frequency amplifiers. mies than any radio battery heretofore Asa “C” Battery the Eveready “Three” developed. prevents distortion and excessive flow of If vou have any battery problem, Radio current from the “B”’ Battery, lengthen- Battery Information Headquarters will ing its life. It is a wonder worker that solve it for you. Write G. C. Furness, saves its small cost many times over. Manager, Radio Division, National Car- Connect it in your audio frequency ampli- = bon Company, Inc., 116 ‘Phompson Ave fier and note the difference. Full direc Long Island City, New Yorl NATIONAL CARBON COMPANY, Inc., New York—San Francisco Headquarters for Radio Battery Information CANADIAN NATIONAL CARBON CO.,, Lit EVEREADY Radio Batteries -they last longer

Page 66

BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY

90 ee ee ee g . . = ——— | Angular Dresser Saves Time in Truing Grinder Wheels ' [‘ THE average shop not equipped with means for dressing angularly the :

wheel of a surface grinder, the usual method is to clamp a parallel to an angle iron and run the diamond block up and down on this. Not only is the accuracy | | eeeat to obtain by such a method, but | it is a tedious job. By constructing the fixture illustrated, 7a File for Every Purpose — | the operation of dressing wheels is simpli-

ANY \ \ ————

\\\

SE

] you can ais 1, . < 4: = BU HING DRIVE FIT a S CT é” 44 - ew, a { C) e Key OLE WITHOUT : i 4 : 4 = Bu ON AXIS e | oe eye 5S" ‘ier a a i8°THDS. K— 5" ' ' v= 5" ‘! rE CG ty al d Details of base, back plate, axis bar, adjusting fixture, and the necessary bolts So much depends upon good files and proper fied materially. The top and sides are methods of using them, that every young made square so as to permit the use of a . 1 h f fil bevel protractor for setting the axis bar. mechanic should master the art o Ing as The axis bolt, which is forced into the bar EZ a necessary step to the job above. in a press, is made so as to fit the bushing 7% in the back plate tightiy. Whenever the a Among the thousands of kinds of NICHOLSON joint becomes too loose to remain fixed, y Bilas neil ao dike: Seow every purpose — which, | the bushing can be renewed. The T-slot ; ~ ‘ ; . 5 . ae because of extra sharpness, greater uniformity and GRINDING yf longer life, assures better results. ai Sp WHEEL Take your Hardware Dealer’s tip—he nm. “LE eee knows which NICHOLSON Files you “eT need. And NICHOLSON Files are all ready to go to work, requiring no PING breaking in. a 5 ae ric CHUCK Providence, R. ley V. S.A. angular wheel to finish a forming tool NICHOLSON FILE CQ, | . | Grinding duplicate pieces and dressing an ' | } | passing through the axis bar is utilized for Rey Ls | clamping after fine adjustments are made Frve [ Sc y ee ae ir: by means of the adjusting fixture screws. |

For fine work the fixture can be set by rie Cc U S A means of a sine bar. arges: Mea 5 ° T} — xt ne Oy worlg (TRADE MARK) re whole fix ure, excepting the axis mate (Continued on page 94) | Se = | ; ree) |

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POPULAR SCIENCE MONTHLY 91 « fer Economical Transportation ) / ed | = te he = ] lal a zle Superior os : Utility Coupe ut *6 : 40 )li- fo. b. Flint, Mich f 7 Is F The Small Famil i y The world’s lowest priced _ it has all the airiness of an high-grade closed car open car in summer. exactly meets the require- The plate glass windows re ments of the small family. are extra large. The wide a d 4 m : oors make it easy for - Father uses it daily going h Te: “ ot El a k mother to enter or leave “a _ = _ © WOrk. with baby in her arms. . Evenings and Sundays it ; ; Finally, and most impor- holds the young family ay tant, its low price and low - comfortably, protecting maintenance costs make it ~ baby from winds, storms feasible for the family of ) and cold in winter,and yet modest income. Chevrolet Motor Company, Detroit, Mich. Division of General Motors Corporation or — ianaointten a i nie Neates sereatnorerins | Prices f. 0. b. Flint, Michigan Dealers and Service Stations every- by two Canadian plants give us the | Superior Roadster - - - $490 Commercial Cars where. Applications will be consid- ee eanety te | Ce Uniling Couns - =. O00 Suaetor Light Delivery - 5 | ret Pom highgredadectenonly xis make a Superior och - i - = 795 Utility Express Truck Chassis 550 for territory not adequately covered

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92 Mr. B. M. Oliver, of St. Louis, Heating ae Expert, has in- 2 vented a New Kind of Heat which gives Three Times the ~ Heat of Coal. | DON'T BURN POPULAR SCIENCE MONTHLY A Amazing New Invention Does Away With Dirty Coal and Wood. Gives Three Times the Heat in Any Stove or Furnace O longer is it neces- sary to pay exor- bitant prices for coal and wood—or to face the uncertainty of actual coal strikes and_ shortages. No longer is it necessary for any woman to give her best strength and energy in endless back- breaking servitude to a hot, mussy heater, cook stove or furnace. No more dirty, heavy coal and wood to carry and lift—no more clouds of ashes to breathe or back-breaking scuttles to empty—no more fires to build, bank or watch—no more heat- ing problems—no more cold rooms in Winter—no more frozen, bursted furnace pipes— no more suffering from lack of quick fires in uncertain Fall and Spring—and no more wor- ries about coal shortages, poor quality or high prices. An amazing invention ends all this forever and makes any type of cook stove, heater or fur- nace, an automatic heater that can be regulated to any tem- perature by simply turning a valve. The wonderful inven- tion of Mr. B. M. Oliver, fuel expert of St. Louis, hasnow been perfected so that there is a model that can be installed in any coal or wood stove in one minute’s time, and then actu- ally gives 3 times the heat of coal if wanted—or can be regulated to a tiny flame by the simple turn of a little valve. And at a cost any family can afford, any hot air, hot water or steam furnace can be converted into an automatic oil burning plant, without noisy motors, without electrical connections, without any moving parts. Cheap, Clean, Simple Mr. Oliver calls his inven- tion the Oliver Oil-Gas Burner because it uses 95% air and only 5% oil (the cheapest fuel there is), turning them into an actual gas that burns with an No ve m mc an he or no

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tu- ‘oal ted ple at rd, am 1to nt, yut rut on - 1er nd uel ito ith

an intensely hot, clean flame. No wicks, no smoke, no odor. Fits All Stoves Without Change Mr. Oliver’s wonderful in- vention is made in 16 models to fit any kind of cook _= stove, heating stove or furnace. No holes to drill, no bolts to fas- ten,nochanges WEGYEVOT. 1 Oe Suaply-setsin © "ee. Beet « firebox. Abso- lutely safe. It lasts a life- time. No wonder housewives are clamoring for this wonderful device. No wonder Mr. Oliver receives letters like these: Mrs. W.N.Spencer, of Conn., writes, “The Oliver in my _ heating stove works like magic. It is wonderful to have quick heat and no work.”’ Mr. Elijah Mc- Clease, of Va., says, “It works fine. All my friends want one. I will get their orders.” A let- ter from Mr. S. K. Pedro, of S. Car- olina, says, “Beats all other burners seen in this coun- try. A sensation.”’ Mr. George Flynn, of Michigan, writes, “It is cleaner, cheaper, hotterand steadier than coal or wood. Only cost me $5 for two months.” Perfect Heating Guaranteed r

The Oliver burner makes any range a gas stove—on Now, once and for all times, do away with household dirt

Fits all types of Hot Water, Hot Air or Steam furnaces, without changes to your present plant. POPULAR SCIENCE MONTHLY and drudgery. The Oliver in your stove, heater or furnace saves hours of work, thousands of needless steps. Already Oliver burners are installed in over 150,000 homes. Their per- formance has been so thor- oughly tested that Mr. Oli- ver will abso- lutely guaran- tee perfect heating forany Oliver burner you install.

Coupon Brings Free Low Price Introduc- tory Offer Send immediately for the Free Attractive Booklet, “New Kind of Heat,’’ which tells all about this amazing foo

new __—siinven- tion, shows yae T 1] ‘ “ j p omens exactly how it ee works and ~<a, how it is dif- ferent from all other burners. Thecoupon below will bring you this information absolutely free, without obliga- tion. And if you mail the coupon at once you will be in time to re- ceive Mr. Oliver’s very Low Intro- ductory Price. You should have your Oliver in- stalled immedi- ately. By act- ing quickly, by sending in your name at once you will be entitled to Mr. Oliver’s Special 93 Low Price whether you buy now or later. So get this coupon in the very first mail. Agent Makes $215 in One Day — More Agents and Distri- butors Wanted Mr. Oliver is also looking for agents, salesmen and distribu- tors. Oliver agents are making fortunes. F. B. Bentley, of Phila., says, “Ye gods! some seller. I made $215 today.” J. Carnegey, S. Dakota, writes, “Making $1,000 a month.” A. M. Russell, Conn., $258 per week. Mrs. Selder, Kans., made $100 a month, spare time only, in her own home. If you want to earn $50 a week spare time, or $200 a week full time, write for FREE Sample Case Sales Plan. [If you can swing a whole territory and want $15,000 to $50,000 and more a year, wire for sales plan. Address Mr. Oliver personally at ad- dress below. OLIVER OIL-GAS BURNER CO. B-54 Oliver Building, St. Louis, Missouri Canadian Distributor B-54 Oliver Bldg., Toronto, Ont. Oldest and Largest Manufacturers of Oil-Gas Burners in the World

; 4m i Sizes to fit all heating stoves give warm room at once—no_ waiting for fires to come up. It Brings Free Low Introductory Price Offer! OLIVER OIL-GAS BURNER CO., B-54 Oliver Bldg., St. Louis, Mo. Gentlemen: Send me your free book, ‘‘New Kind of Heat,’’ and your Special Low Price Introductory Offer. I am in- terested in a burner for Coal —, Heating Fur tange Stove ' Wissen ser Address aere ee a Co oO If interested in selling in full tim or spare time check in square here.

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ANDVARNISH Linduro Enamel Vernicol Stain Automobile Color Neptunite Varnish With these four splendid products in your house you will be prepared to put a permanently beautiful finish on any piece of work you may make. The Lou e Brothers Dealer in your town can supply you u ith one or all oj these products. re of a (Beautiful Finish When the manual labor is done on a medicine chest, table, swing, flower-box, or any useful article for the house that your hands have con- trived—when it is time to apply the finish—then choose wisely so that the finish will enhance the beauty of your handiwork. And whether you want to finish the piece with varnish, stain or enamel, you will find among Lowe Brothers Paints and Varnishes a product expressly made for that purpose—a product that you can be sure will produce a finish of lasting beauty. For fifty years.Lowe Brothers Paints and Var- nishes have been used by the amateur workman and craftsman furniture finisher. There is one dealer in your community—The Lowe Brothers Dealer—who can supply you with these famous products. Visit this dealer. He will not only supply you with a specifically prepared paint or varnish, but he will give you expert advice as to how to use it. THE LOWE BROTHERS COMPANY Dayton, Ohio Toronto, Canada BRANCHES IN PRINCIPAL CITIES Factories Goat PAINTS &VARNISHES BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY Angular Dresser Saves Time (Continued from page 90) bolt, is left soft and must be ground all over. The T-slotis cuton amilling machine by means of a circular attachment or it can be done on a spiral head. The back plate and »as2 plate can be either cast iron or machine steel.— HENRY S. LARABY. Special Reamers and Cutters Constructed in Two Parts PECIAL reamers are often useful in the machine shop. Figure 1 shows a tool for drilling and countersinking at one operation. A piece of round steel is shouldered at one end, drilled through the center to fit the drill, and cut in half through the center. It will accommodate three sizes of drills, such as 3/16, 7/32, and ly in. A cutting bevel is ground on the | edges of the reamer and the drill and Yy 3, ROUND Ung’? Ron soo FiG.3, A drill and countersink, a cutter for pointing rods, and an end mill reamer are clamped together in a drill | chuck. The split reamer adds to the rigid- ity of the drill and reduces breakage. Figure 2 shows a two-piece pointer that would be difficult to make in one piece. Before making the cutting edges the reamer is cut in half, and each piece is finished separately. An end mill—also made in two sections —is shown in Fig. 3. A hole passes down through the center of the tool into which an iron rod of any desired length may be placed to space the halves properly. When working on tenons that are to be finished at a definite length, the rod will act also as a stop.—O. W. MIELENz, | Philadelphia, Pa. On Next Month’s Schedule N INSPIRING article on suc- | cess in the shop, by M. E. Dug- gan, one of the best known pattern- makers in the United States. W. Burr Bennett, an automotive engineer, describes a connecting rod reamer that is useful for the small automobile repair shop. Other articles of practical value to the shopman will be ‘‘Making Inserted | Blade Lathe Tools,” ‘‘Fitting a Small Tool Vise with a Dual Purpose Base,”’ “A Depth Gage for Simultaneous Drilling and Spot Facing,” and ‘‘A Hammer Impact Key Puller.” ‘Making the Most of Boring Tools’”’ and ‘‘What a Machinist Should Know about Hardening,”’ are two longer fea- tures scheduled for early publication. % BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY

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all ne it ick ast ie rs irill pid- hat | ece, the | e is ions own nich | y be rly. » be will SNZ, mt betes CD bee O your pipe. POPULAR SCIENCE MONTHLY 95 Get this, men- Acomplete assortment of the world’s finest smoking tobaccos — sent to any smoker anywhere— on 10 days approval new idea for Pipe-Smokers: 12 famous tobaccos, packed in ahandsome Humidor—shipped to you ‘irect to help you find the soul-mate for @ GUARANTEED BY Ske Se . aa 4 OST men have written - their | John Hancocks on a lot of “dotted lines.’ But, if you’re a pipe- smoker, we'll wager that you’ve never signed a fairer, sweeter con- tract than the little coupon at the bottom of this page. Justa few strokes of your pen—and you can end your quest of years for a perfect smoking tobacco—drawing dividends for life in unalloyed pipe- satisfaction. But we are getting ahead $150 ) >st for s\ ‘agi ASX Tes allel these If you were tot saccos 11 ull size al “b ~ raeeie cost would De: of our story. -) . Ae F mar x0 rr h et a Phe average aT" 1 CyubeOt © °F = Leb re om pipe - smoker aperial Cube C ul Im} seh, Cul 35 isthe greatest W une é g ' Old Eng oi, ee is little experi- 7 on menter in the Tee a world. He’s williLatakia = °° “ae forever try- Louisiana Pernque Toral - $35 ing a “new ‘um dor Sample J ” * But throws seca one, Co nfi- von Gunny of exch dent that some day he’ll find the real affinity for his pipe. Knowing smokers as we do—and knowing tobaccos as we do—we felt that we'd be doing a friendly turn for everybody if we found a way to settle this question once and for all, to the satisfaction of every smoker. So we created the Humidor Sampler. Intoa bright red lacquered humi- dor case, we have packed an assort- ment of twelve famous smoking tobaccos—covering the whole range of tobacco taste. To test these 12 tobaccos is to go the whole route in delightful pipe tobacco experience, trying out every good flavor and aroma known to pipe connoisseurs. There are myriads of different brands of smoking tobaccos on the market. But of them all, there are 12 distinctive blends which, in our opinion, stand in a class by them selves for superlative individuality of flavor, aroma and smooth, sweet, even quality. These twelve decisive blends—the twelve “primary colors” of tobaccos —have been selected for the Humi- dor Sampler. When you have tried these twelve, you have tried the best; POPULAR SCIENCE MONTHLY if your tobacco-ideal is to be found anywhere, it must be one of these. Ten-Day Approval Offer We are eager to send the Humidor assort- ment to any smoker, anywhere, on ten days’ approval, Send no money. Just sign and mail the coupon. That will bring you the Humidor assortment direct from our factories to your den. When the postman brings the package, de posit $1.50 with him, plus postage. If a ten-day try-out of these tobaccos doesn’t give you more real pipe pleasure than you’\ © ever ha 1 be fore, be sides revealing the one pe rfect tobacco for your taste—the cost is On us. Simply return the Humidor, and you'll get your $1.50 and the postage back pronto— id pleasantly. The coupon is rvant; use It. your cbedient ee eee ae ee Baltimore, Md, Please send me, on 10 days’ ape proval, one of your Humidor Samplers of —= . twelve different smoking tobaccos. 1 will pay postman $1.50 (plus postage) on receipt —with the understanding that if I am not satisfied I may return Humidor in 10 days and you agree to refund $1.50 and postage by return mail, = Name ae Address —_ Note:—If you expect to be out when post- man calls you may enclose $1.50 with coupon and Humidor will be sent to you postpaid.

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96 Another Popular Pexto Item— Samson Ratchet Bit Brace with Ball Bearing Chuck and Head.

Good Tools Make Good Work Easy— =e =— No. 30 Box Joint Plier Drop forged steel, raised cutters, square opening in back, perfect fitting joint, easy action.

1819 Original Snip F< ged from best grade steel, they have given satisfaction for over one hundred years Fa

Ke

Sy 4

1 tee} No. 91! Hammer Drep forged steel, heat treated and tempered, excellent finish and properly balanced.

No. 3 Solbar Screw Driver Forged steel bar runs entire length. Fluted hard- wood handle sex urely held. OR To take pleasure in your work you need good tools, tools that will do the job required of them. PEXTO Tools are backed by over a century of tool making ex- perience. They are of first class quality and fully guaranteed. The line consists of Bit Braces, Auger Bits, Squares, Chisels, Ham- mers, Hatchets, Pliers, Monkey and Pipe Wrenches, Angle Wrenches, Screw Drivers, Snips, Compasses, Pruning Shears, Dividers, Calipers, Pincers, Soldering Coppers, Nail Sets, and many other small tools. Booklets covering our important lines are available for free distribution. PEXTO TOOLS are carried by practically all progressive dealers. WORTH WHILE TOOLS The Peck, Stow & Wilcox Co. Southington, Conn., U.S. A.

BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY

Shut-Off Pedal and Pilot Light Improve Shop Blower HE blower in a shop is usually the cause of much annoyance, either be- | cause the gas is turned on when not in use, | thereby causing waste, or because it is out | and matches are not handy for lighting it, | By attaching a pilot light and pedal | control to it, as illustrated, this waste | and delay are eliminated. A spring is | attached to the handle of the cock, as | shown, to hold it closed, and a wire is led

SPRING-CLOSED GAS-COCK PEDAL. To turn on this blower, the pedal is pressed down and caught under the bracket from the handle to a pedal. By pressing down the pedal and hooking it under a bracket on the floor, the gas is allowed to | flow to the burner. When the pedal is | released, the spring closes the cock. A pilot light is led out to the nozzle from the gas pipe in rear of the main sup- ply cock. A small cock in this line regu- | lates the amount of gas flowing to the pilot at all times so that there is always a flame available when the blower is needed.

Calipering Flanged Work N EASY way to measure the thickness of a web difficult of ac- cess is that illus- trated. First,make prick-punch marks on the legs of a pair of outside cal- ipers, as shown. | Pass the points | over the flange and | set them against the surfaces of the web. Then seale the distance Y. Now remove the calipers, move the legs together until the punch marks are Y distance apart, and the distance between ‘the points will represent the thickness of the web X.

| Dust ona concrete floor can be pre- | vented by painting it, when perfectly dry, with boiled linseed oil thinned with gasoline. Several coats should be given until the surface is glossy.

im Vn

RETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY

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sht 7 the r be- 1 use, is out ng it. pedal Waste ng is k, as is led sed essing der a red to dal is 10zzle 1 sup- regu- o the ays a eded. 2 web. PMove r until apart, ts will ee P ore- rfectly d with given HIRAM PERCY M GHAS: H. STEWA MacMillan’ s Link with | Civilization | A Paragon Radio Receiver is the most dependable link between MacMiuillan’s cour- ageous explorers and a civili- zation eager to hear of their POPULAR SCIENCE MONTHLY AA HEBERT TAEASURER SCHNELL, TRAFFIC MANAGER K. B. WARNER Sacrarany LO OERELAY E mAson’ ip LEAGU Tet wis Anarene en AXIM, PRESIDENT RT. Vice-PRESIDENT THE AMERICAN: AGAIING ccussivEay TO EXECUTIVE HEADQUARTERS HARTFORD CONNECTICUT OFFICIAL ORGAN: @ st Kenneth B Warner, Eviro® Experimental Radio Station OBP Prince Rupert, B C Canad. September 6th. 1925-6 Adams Morgan Company Messrs. ntclair, Ne J- Upper lo Pear Sirs:- am very pleased with thé s another victory I have advised you pefore that I be interested to results of my "PARAGON APPARATUS® but here i for "PARAGON APPARATUS" which 1 feel you will knowe The MacMillan Arcti Maine on June 23rd. on bd c Expedition which left wiscassett, oard the radio equipped Schooner "Bowdoin® planned to keep in touch with the outside world by amateur radio. This they were able to do until they got North of Disco Island, Greenland. After going North of that point nothing was heard of the expedition. And all f{nterested became worried at the ship's apparent silence. The Chicago Radio Laboratory on thie cate of the receiving apparatus aboard the first amateur to get into come I have had Arctic Expedition. This prize RA-10 Regener=- the ARAGON Type munication with the the honor to win doings. ative Receiver an ‘ Read this letter from Jack arnsley whose Paragon Re- ceiver has been picking u these vitally i a ‘ ‘ally important mes- sages, picking up every one, and gettingevery wordclearly. A Radio Receiver could have i ave no higher recommen- Since first ge expedition (who are bour, which is ten Longitude 72.30 We a complete the oe Bulletins on ParagonRadio roducts are yours for the asking ADAMS-MORGAN Co. 18 Alvin Avenue, Upper Montclair, N. J. consider this quite 4 to be able to adv d PARAGON Type echedule with the operator an list of amateur c "Bowdoin" from July ea all of these messege tting into communic in winter quarters of st) on September Tih. 1 d have copied one from then that the expedition nh dation. When you consider of amateur stations in the Arctic but that my the only one with whom they have been able to communicate, I PARAGON APPARATUS" and am glad record for ise you how pron DA-2 Detector-Amplifier. September g to their ation with the *Bowdoin™ frozen in at Refuge Har- Greenland Latitude 78.30 Northe have had 4 working 600 word and one d to the New York World, from the expedition and total of 546 calls) by 20th. and have forward destinations. as heard hundreds station has been addresse aratuS. q D Y trol 4 L eating ee ly C re 2 Jey al am of my receiving PP D 7 SIDITIT AD CHKILDAT'L ACMA LIT 4

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98 BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY Then and there He was Convinced— There was a mechanic who said he could get other tools than “Brown He Could & Sharpe.” — “cy? , N; = e He said, “I'll try a new Microm- He Did eter of another make. He thought that this other tool would be just as reliable as a It Wasn’t Brown & Sharpe. His work was not as good—and He was dise the tool was to blame. satisfied Finally he made up his mind to buy a Micrometer that he knew He has used he could rely on—and it was a it ever since 3rown & Sharpe. BROWN & SHARPE TOOLS are made in the largest factory of its kind—their accu- racy, improved design, long life and quality have made them the “Standard of the Mechanical World.” Catalog listing over 2,000 different tools, with discount sheet, sent on request. Send for it today. BROWN & SHARPE MFG. CO. PROVIDENCE, R. I., U.S. A. Success with Taps and Dies (Continued from page 86) a tap will cast up and burr the metal so as to make practically a full thread even though a small allowance on tap or die diameter has been made. It is essential that the right kind of tap be used for a particular job. Taps are made with two, three, and four flutes | in the smaller sizes and six or eight flutes | for the larger diameters. For extreme | accuracy a gun tap, with only two flutes, | should not be used, but occasionally a | gun tap will work well on a difficult, rough job. The effect of the various kinds | of taps on different work should be studied. Spiral fluted taps clean out the | chips nicely and all other taps should | have proper hooks on the cutting teeth to afford chip room, Accurate Taps Essential Most careful workers have their own particular set of taps which they keep standard on the leading teeth and main- | tain with a back taper. Such taps pull | easily and cut accurately, while a tap with | a reverse taper will choke and pull hard, | making an imperfect thread. Such me- | chanics never use a tap or die with broken | teeth except in an emergency and then | only after the teeth have been ground down. Neglect to grind the broken teeth almost always results in torn’ threads. There are occasions where even a | damaged tap or die is not availabie. | Lucky is the man who in this emergency | can speedily make a tap for finishing a | rush job. | In making either taps or dies, tool steel of the best’ grade should always be used, For a plug tap a piece of steel of the proper width and length is cut off, chucked in a three-jaw scroll chuck and filed tapered for a distance of about three | threads at the lower end. From that point it is back tapered (smaller at the shank) about .001 in. an inch. If a lathe is not available, the taper must be made | as nearly correct as possible by hand. The thread is then cut with a die opened | up a small amount, and a second cut is | made with the die set at the actual size. | | Soda water or compound is used as 4 | lubricant so as to obtain a high polish on | the finished surfaces of the threads. Finishing and Hardening Taps | | After deciding on the number of flutes, | take a three-cornered file and gash them | in roughly. A round file should then be | used to finish the flutes accurately. In this way the flutes can be made deepest at the lower end, running shallow at the junction of the thread and shank. The tapered or chamfered threads at the lower end are backed off and a flat or square is filed on the end of the shank for the tap wrench. The tap is now ready for hardening. Hold it in a hot flame (Bunsen burner and heat to a bright cherry red. Then quench it in lukewarm or cool water, dipping the tap in vertically and stirring in circles, beginning with the smallest rotary motion possible and gradually increasing the circles. In this way all (Continued on page 100) a

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POPULAR SCIENCE MONTHLY 99 a es ‘al so even / r die| | f tap S are flutes | | flutes | } Teme | lutes, | lly a | icult, | kinds | ve lemperature it the | = Control on THE SIXTH SENSE keep main- OF INDUSTRY $ pull > with hard, HEN the farmer’s wife spun her own yarn and then h me- VW. wove the cloth, the human sense of feeling was roken sufficiently accurate for deciding when the wool had | SIX SENSES then | the right amount of “moisture content” to be made into eS e* Tycos y Jeeling But with the development of wool manufacturing on a 1s. large scale—and all the allied textile industries—the human . S eing ren a | sense of feeling had to be replaced with something more in the Home e ilabie. | § accurate —something infallible. H ° | | Cre : : Pelt 6 Dyeos O fice Thermometer earing gency | This infallible sense so essential to the textile industry An aid in promoting human ling a | the second greatest industry in the country —has been found = Sm ellin | in Tycos—the sixth sense of industry. Fycos Bath Thermometer gJ Ys) ° e ° e Po enabl mu to get t mo . I steel | No longer is the dyeing and preparing of wool, silk, cotton — good irom your bath. Tastin used : Z TREES EGE ee : sats g SOU, and linen for manufacturing purposes dependent on the work- Keo of the man testing the ‘moisture contents” of these materials by sean nit ae see, Candy and t off, feeling them. Thermometer, Sugar” Meter, —- k and By supplying a scientific and exact method of determining an COOknw. [ycos - three | temperature and moisture contents Tycos Temperature In- Jyreos Wall Thermometer . that struments have reduced to an exact science the conversion fo help you maintain a tem- } is vg z = = - . perature in your hou con- at the of animal and vegetable products into textiles. ducive to good health emperature lathe | In every manufacturing process Tycos Instruments for Fees Quality Compass: Con trol made | Indicating, Recording and Controlling Temperatures have J show you the right way in id. taken the guess out of manufacturing. The use of Tycos pened | Instruments insures the uniformity of results that is necessary Tycos Fever TI sesmnereters cut is | to success in manufacturing and selling on a large scale. Patani iat itieliaabiaies ] size. | Tyeos Stormoguide Fees IT ygrometer | ‘orecasts the weather twent fo enable ou to keep the as a] four hours ahead with depend humidity of the atmosphere in ish on | Manufacturers able accuracy. your home correct at all times. : | What do you make? What is your problem of applying Your dealer will show them to you. Ask us, Tycos “the sixth sense”’ to your manufacturing processes. For = on a postal, for booklets on any of the above. 1p every process—in any industry —requiring heat control there | is a type and style of instrument in the Tycos line that you ——— : flutes, | need. Frecs and the MEDICAL Profession them | Write us and literature on any instrument or type of in- Jeos Sphygmomanameter, Pocket and Oflice type en be | strument will be sent you promptly. Or, if you prefer, our Tyeos Urinalysis Glassware, . y Y oh = . ~ y I , - - ‘ y. In experts will advise you in the application of ‘‘the sixth sense’’ Freos lex er Phermometers, eepest in your plant. Bulletins on request. at the | , The Canadian Plant Lj ¢ : } ; tthe Sees BUILDING Taylor /nstrument Companies Jat or TORONTO Main Office and Factory nk for ROCHESTER, N. Y., U.S.A. \ Let ; = ening. urner) | § nll, Then { “ ws water, FF tirring nallest dually ay all | INDICATING + “RECORDING + CONTROLLING ee

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100 BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY Success with Taps and Dies (Continued from page 98) sides of the piece will cool evenly without | warping the metal. | The tap will then be as hard as glass and must be tempered. Hold the tap with | a piece of wire, one end of which is | wrapped around the threads, and pass the whole length of the tap through the flame, allowing the shank end to get the most heat. The shank will first turn yellow and then a straw color, the color going down toward the threaded portion. This can be observed best if the shank and the inside of the flutes are polished. When the end of the tap shows a straw color, quickly dip it in cold water. Taps hardened and tempered in this way will have hard cutting edges and tough shanks and bodies. + The general method of making tapered and bottoming taps is the same as for the plug taps described. The difference lies in the tapering of the blank. The tapered tap has the lower end turned straight for three threads, then tapers for six threads and is straight except for a _ .001-in. back taper the rest of the way. The bottoming tag has a chamfer on the lower ) thread only. Steps in Making Dies RATCHET # BREAST DRILL : ‘ 7 this When making dies, a layout five or 10 1; " c " times the size of the actual tool should - be made first. This diagram then is 1g t weig t reduced to actual size and traced on the breast drill See how easy the two- speed ratchet mechan- ism works. Changes of speed and changes of motion are made by a turn of a dial. Frame of aluminum alloy. Holds round-shank drills 0 to 14 inch, The Goodell-Pratt catalog describes each of the 1500 Good Tools. Write for it—free. Goodell-PrattCompany Greenfield, Mass., U.S.A. Zant Makers of Mr. Punch GOODELL PRATT 1500 GOOD TOOLS blank. Before laying out on the blank, the latter should be sawed and faced on both sides to the thickness required. The first holes drilled are the chip clearance holes. These then are plugged tightly with soft steel plugs, each one being a driving fit. The central hole is drilled then and reamed to size, taking care that the diameter agrees absolutely with the root diameter of the thread. The chamfer of the lower end should taper out in three threads, while that on the upper end includes one thread only. The die then is tapped with a taper tap starting at the bottom or tapered side of the die. Lard oil provides a good lubricant for this operation. The finishing cut should be made with a bottoming tap. A weakening hole next is drilled and the saw slot is cut from the inside, leaving a thin bridge on the outer circumference for the purpose of holding the metal rigid during the hardening process and preventing the die from warping. This bridge is filed away when the die has been tempered. Countersinks then are made in the saw slit and one side to receive the points of the side and set screws respectively. At this time the chip hole pins are driven out and the rear of the lands are backed off with a flat file. The hooks or lips of the cutting edges then are touched up and clearance is filed on both top and bottom chamfers. The die is now ready for hardening. Wrap a piece of wire around the thin section of the die and heat the die to a | cherry red. Quench as in the case of the tap and draw the entire die to a deep straw color. The temper can be improved (Continued on page 102) HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

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id its ly. en ed of up nd 1g. iin ya che ep ed POPULAR SCIENCE MONTHLY 161 *, asleep or awake SUIMOIp skemye as,A£ay} i ur Man’s whiskers, like the troubles of people who live beyond their means, are always growing. Clocks may stop, lecturers may pause to consider, but, day and night, as long as he lives, man’s whiskers are always growing. —From “The Hair Apparent,” Part I, Chap. IV. 0 C) CCEPTANCE of the fact that a facial briar patch is not likely to contribute to a man’s success in scientific pursuits, in business, in love, or in any other worthy endeavor is spreading rapidly. Most professional men, as well as most business men, now shave daily. This is the only means of keeping man’s always growing beard in proper subjection, No matter how heavy your beard may be, or how tender your skin, you can shave closely every morning, and be comfortable, if you lather with Colgate’s “Handy Grip” Shaving Stick. It makes shaving easy, and always leaves the face cool and refreshed. The “Handy Grip” and metal container will last for years. After your first shaving stick is used up you can buy Colgate “Refill” Sticks for the price of the soap alone. It is not uncommon for a Colgate Shaving Stick to last for a year or more in daily use. Colgate’s “Handy Grip” Shaving Stick i$ unequaled for put- ting comfort, convenience, and economy into the daily shave. OLGATES having Stick “HANDY GRIP’AND REFILL Pas parece ONAN POPT)TLAR SCIFNCE MONTRHIY 12

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Williams

OMPARE the Williams’ cap with any other. There’snothinglikeit.Com- pare Williams’ in any and every other way: You’ll like its lather —un- cannily swift in the way it softens tough beards. For years the envy of other shaving soap makers. You'll like its purity—no col- oring disguise is needed in Williams’. It is a natural white. You’ll like its soothing effect —no complexion soap in the world is more beneficial. And last, there’s the Hinged Cap! Add to your Williams’ shave this “extra dividend” of a cap that you can’t lose. Then compare.

Youcan’t lose this cap Shaving Cream Have tried Williams’ Velva ? The

you Aqua new scientific formula for after-shaving use? Sample free. Write Dept. 102 The J. B. Williams Co., Glastonbury, Conn., The J. B. Williams Co., Ltd. (Canada), 1114 St. Patrick St., Montreal E19-100 PAGES FREE

this “ I arnin You, too, can make work in the whole motor car ine baaers Auto Painting Over 2,000,000 new cars each year— 13,000,000 cars in use need repainting in 12 months. Only trained men can do this. Factories, dealers, custom shops, all bid- ding for men. Demand exceeds supply everywhere. We Fit You for Big Pay in Few Weeks This thoroughly equipped school auto pli ints structi gtheh ighe st paid -approved by big teaches you in 8 to 12 weeks rsonal in m by experienced, practical auto painters. Every brane h covered. You can hold high-pay job or run your own shop—be the head of big business. GET FACTS JODAY Write us today for facts about this wonderful trade ind our me sthods. Don’t delay! This is the greatest opportunity in any industry, Write today for details— then you be the judge. DETROIT AUTO PAINTING SCHOOL 1408 Van Dyke Avenue Detroit, Mich.

104 ‘world. 40 diagrams o

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HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Success with Taps and Dies (Continued from page 100) by repeating the operation several times. The weak section of the die should then be drawn to a deep blue, taking care not to change the temper of the lands. The bridge is also drawn blue and is later filed away. The blue temper increases the tenacity of the steel and makes the weak section act as a spring. Correct proportioning of a die in rela- tion to chip room, lip angle of the cutting edges, and the proper backing off of the chamfered portion of the thread are highly | important features in the making of successful cutting and wearing dies. All small taps and dies should be marked with their sizes before hardening. ‘Slip’? Flywheel and Gear Will Prevent Tool Breakage Oeprictene! repairs and lost time can some- times be prevented by fitting a pro- | duction machine with a slip drive along | the lines illustrated. | Hundreds of dollars weresaved bysuch a revision in design of an automatic machine similar to a press, which had a heavy fly- wheel keyed to the drive shaft. Whenever the work caught or a foreign body dropped into the tools, the expensive set of tools was ruined and the machine placed on the |

idle list. These breakdowns have been | ORIVE rr, STOP PLATE LEATHER ~ | FIBER ree G

/ disk SET PIN | 4K STEEL PLATE SCREW) Oe ADJUSTING 2 ft te NUTS F ng . SPRING iN ve fe / eo

SLOTS IN Pak SPRING pisc Typical installations of friction drive that slips when subjected to any unusual strain eliminated and all later machines have | been similarly equipped. The driving flywheel in this case had a | good-sized hub that was faced off on both | to which | leather disk, was | mounted on the inner side of the wheel | and held in place on the shaft by a key | and setscrew. A leather-faced steel disk | sides. A cast-iron stop plate, was riveted a !4-in. was floated on the shaft on the outer side of the wheel hub as shown. forced against the hub by a large spring washer formed from !<-in. steel and tem- | pered. To improve the springing quali- ties of this dish-shaped disk, four slots | were made in it. A large nut on the end of the shaft was brought to bear against the spring disk. The grip tension can be adjusted so that the flywheel will carry the load, but | will slip when a blank or other object gets | In other | instead of the | caught and binds the tools. words, the flywheel “‘gives’’ tools, which means longer tool life. The illustration shows a “slip” gear mounting that is practically the same ar- rangement as the flywheel mounting de- scribed, except that a heavy coilspring takes the place of the dish-shaped spring disk.—C. M. WILcox.

This disk was |

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yr > ae f ro

POPULAR SCIENCE MONTHLY

nee { " >. New York's Grand Opera ~ one of the many events enjoue

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To measure the success which Magnavox engin- eers have accomplished in the design and manu- facture of Magnavox products, remember that they have been sold in far larger quantities than any other radio units in the world. Magnavox Reproducers horn and 1 stage of amplification R2 with 18-inch curvex horn $60.00 $59.00 R3 with 14-inch curvex horn $35.00 A2-R consisting of electro-dynamic M1 with 14-inch curvex horn. “abt € with eae: prs Requires no battery for the field. a nw ne Nn ene $35.00 $85.00 Magnavox Power Amplifiers Al—l-stage . . . . . $27.50 A1-R consisting of electro-dynamic AC-2-C—2-stape. . . . $55.00 Reproducer with 14-inch curvex AC-3-C—3-stage. . . . $75.00 Magnavox Combination Sets Magnavox Products are for sale at Registered Magnavox Dealers everywhere. Write for new 32-page Magnavox Radio Catalogue. THE MAGNAVOX CO., Oakland, Calif. New York Office: 370 Seventh Avenue Perkins Electric Limited, Toronto, Montreal, Winnipeg, Canadian Distributors

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104 POPULAR SC{ENCE MONTHLY In high quality receiving sets, the vacuum tubes — This symbol the heart of their of ua protection fine performance — bear the name Radiotron and the RCA mark . Be sure to look for this identification when, you replace your tubes. —y., icsailli\ Pil itsasgant i | A ——— ty . ) 7 SS Radiotron Radiotron WD-12 . Radiotron UV-199 ; } \) Radiotron UV-200 Radiotron UV-201-A Send for the free booklet that describes all Radiotrons and Radiolas. Radio Corporation of America re en Sales Offices: | 233 Broadway, New York 10 So. La Salle St., Chicago, Ill. 433 California St., San Francisco, Cal. RADIO CORPORATION OF AMERICA Dept. 112 (Address office nearest you Please send me your free Radio Booklet. Name Street Address Cit R.F.D REG. U.S. PAT. OFF. wn a ee

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HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 105

iif a ee ane — _— Ty How to Make a Set of Accurate | Yj, Cast-Iron Surface Plates Se I E y By Henry S. Laraby ee id hh V ery PRECISION surface plate is a lux- ury seldom found in the small shop. | , This is, of course, due to its high cost and | to the notion that accurate surfaces are | dificult to produce. For years I, too, | ljabored under this impression, but finally | decided to put my odd moments to better use by making a set of three. Once the | pattern is completed and the castings are | yi, 3 Corner of ,\4 » he A} =" the Earth Science isWatching and

2, TAPER _4"WAX FILLETS ‘22 Working to Disclose the 32 TA 4 \NAX Fi i) > a . . . ‘ i is T verse through his amazing scientific achievements. nN meg nage At last this romance is yours—told for the first time in one flowing story 1 | u yt : that throws open to you the whole wonder world of science. F =—J 4 = i

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. Because every man, woman, and child in America ought to know about this epoch-making work, the publishers have prepared, for free distribution, a most interesting and strikingly illustrated bro- chure that tells the wonderful story of The Outline of Science. \Vith four plates in full color and over thirty half-tone pictures of scientific marvels it shows how this splendid work tells of all the miracles of science since the beginning of time —how it reveals for you The Ro- mance of the Heavens; Man’s Rise From His Earliest \nces- try; Marvels of Insect, Plant, Ani- mal, and Bird | ife; Miracles of Elec- tricity, of Chemistry, of Aviation, and a thousand more things of absorbing in- \

FINISHIN i NAIL OF RIBS RIBS CROSS UNTIL FINAL ASSEMBLY A condensed as- sembly view of details of an 18 by 24 in. surface plate is shown above. Allow- ance has. been

: : re » indeed, is , st amazing ine ta Os 2 terest. Here, indeed, is the most ama ing mensions for the story ever written: the cream of the world’s shrinkage of the scientific genius. Don’t fail to get your copy castings. At the of this splendid booklet with its remarkable story and fascinating pictures. It entails no cost or obligation on you whatever. The coupon brings it immediate ly. Mail it now. G. P. PUTNAM’S SONS Dept. 138 2 West 45th Street New York right are shown the three steps in scraping the plate to a true surface

made from it, the plate can be left for those hours when work is slack. The pattern is made of white pine. Ten strips 25 in. long are planed accurately to a size of 1 9/16 by 15/16 in. Two other | strips 134 by 15/16 by 25 in. are made to serve as side strips, being slightly wider so | as to allow for truing up the top when | o, Cal. completed. These are now laid side by side with the grain running in the same direction lengthwise so that the top can be planed properly. Also, the end grain | should be reversed on every other strip to prevent warping of the whole when glued together. The strips are then glued to- 6 Se are gether and allowed to harden. The top ae Sa OE . ey Ma | next is planed on one side. = =3 : (Continued on page 106) This Coupon Brings Your Cop G. P. PUTNAM'S SONS, Dept. 138, 2 West 45th Street, New York. Send me by mail, without cost or obli gation on my part, the free booklet with sur color plates and over thirty half ne illustrations describing The Outline of Science.

EC he Char

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Aa CSSLLLRION Y BS 782 Priceless Service Despite fire or storm or flood, a telephone operator sticks to her switchboard. A lineman risks life and limb that his wires may continue to vibrate with messages of business or social life. Other telephone employees forego comfort and even sacrifice health that the job may not be slighted. ‘True, the opportunity for these extremes of service has come to comparatively few; but they indicate the devotion to duty that prevails among the quarter-million telephone workers. The mass of people called the public has come to take this type of service for granted and use the telephone in its daily business and in emergencies, seldom realizing what it receives in human devotion to duty, and what vast re- sources are drawn upon to restore service. It is right. that the public should receive this type of tele- phone service, that it should expect the employment of every practical improvemert in the art, and should insist upon progress that keeps ahead of demand. ‘Telephone users realize that dollars can never measure the value of many of their telephone calls. The public wants the service and, if it stops to think, cheerfully pays the moderate cost. where letter — get ment plan Furnaces KALAMAZOO S Rochester Avenve AMERICAN TELEPHONE AND TELEGRAPH COMPANY AND ASSOCIATED COMPANIES BELL SYSTEM One Policy, One System, Universal Service Write for Free Bargain Catalog Someone orders your rangefromthe factory regardless of you buy. Why not get factory prices yourself and . save money? It is easy to deal with Kalamazoo—simply write a quick, safe delivery. Long free trial.Less than $15 down brings any Kalamazoo range on easy pay- 200 or more styles and sizes— porcelain enamel, steel, cast iron, malleable construction. Special offer for limited time only , too—for any size home. Write today. TOVE COMPANY Kalamazoo, M ADD $5.00 a DAY to YOUR PROFITS with a TORIT ACETYLENE TORCH No. 13 For radiator repairing, general soldering, light braz ing, heating, battery repairing, etc. Produces instant hot flame, works rapidly Furnished with 4 differen ps and soldering copper, enabling you to do a wider saa ak a \- range of work USES ACETYLENE ONLY A splendid use for discarded auto acetylene tanks, Many owners make the Torit No. 13 pay for itself in a single day 5 tubing and lorch with 4 different tips, soldering copper, 5 ft. onnection for auto acetylene tank $7.50 Order today from your jobber, or St. Pau! Welding & Mfg. Co., 164 W. 3rd St., St. Paul, Minn. How to Make Surface Plates (Continued from page 105) The ribs also are made of white pine. three being 2 3/16 by 34 by 17% in., and three, 2 3/16 by 34 by 207 in. These are planed down to the dimensions shown on the drawing of the finished plate, and notched half way. The ribs are then glued and nailed to the smooth side of the top and the other side is planed, the sides are squared, and a taper is made on the edges all around the top. The dimensions of the top now wil be sufficiently large to allow for shrinkage Next, smooth off the bottom edges of the ribs, sandpaper the pattern and shel lac over all. After a day, put 14-in. fillet; of wax around the rib bases and give two more coats of shellac. Finishing the Iron Castings The pattern is now ready for the foun- | dry, where three castings of gray cast iro: should be made. distinctive markings before any work o1 them is done. First the plates should be planed as accurately as possible. Then castings Nos 1 and 2 are trued up by means of a straight edge and scraper. One of them is coated with Prussian blue or red lead and the two are rubbed together. In this way th ee high spots can be located and removed | equal to half the error is scraped off each. | with a scraper. Leaving No. 1 aside for the moment, repeat the operation with 2 and 3, but do not scrape 2 at all. By comparing 3 with These should be given | | any errors are detected and an amount | Continuing in this way, rescrape 1 and 2, then 3 and 2, finally checking with 1 and 3. | This is continued until all three check. How the scraping should be done is in- dicated in Figs. 1, 2 and 3, on page 105. By this method a careful workman can make three very accurate plates in his leisure moments. Jig for Drilling Handwheels 7 simple jig illustrated is for holding | a handwheel while drilling holes in the rim. The taper key is removed and the wheel is placed on the center pin. TWO PINS ORILL BUSHING TAPER KEY HOLDS WORK Three pins locate the handwheel accu- rately and a taper key holds it in place Two | pins then are placed in seats in the jig to hold the wheel by bearing against one of the spokes and the key is driven in, thus | locking the wheel. guide the drills.—J. H. MOORE. HARD silver solder of low fusing point that is used extensively by one of the largest electrical companies is com- posed of 34.36 per cent copper, 49.24 per cent silver, and 16.4 per cent zine. Borax is used as a flux. Two drill bushings } ab m¢ ney sta an( col an bes for of pos VOL ad are sta fill =— |!

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nd are on ind to her da the | will ge. | of he] lets two Nos ight ated the the yved lent, | | it do | with | Ount | | ach. | id 2, | id 3. ding | n the 1 the T wo | Qa ig to ne of thus | ings | | | | using | y one com- 4 per sorax POPULAR SCIENCE MONTHLY 107 : A Perfect Glareless Headlight At Last Distributors—Agents and Dealers—Can Make $3,000 to $15,000 or More a Year The Detroit Safety Headlight Devices ) absolutely solve the greatest menace to auto- mobiling—the headlight glare. This is a new, simple device and fits any model of any ear. Installed easily and quickly by anyone. Used with low priced plain glass lens. It They sell on sight Appeals to fairness a demonstration sells anyone. strated in store, home or on ear. adds style and dignity to any car. It absolutely concentrates the light down on the road, not up in others’ eyes. Drive with all the courtesy of the road with bright lights on. The glare is positively eliminated. Will last a lifetime. Will not rust, corrode or deteriorate. Meets every legal requirement. They are the best headlight devices made and stand any test. Detroit Safety Headlight Devices Sell On Sight {asily demon- Sold on 30 day trial—_never taken out. no one wants to drive others to death in ditch. Owners urge others to buy. See illustrations as to installation and effect. Exclusive Territory—Newspaper Advertising—Installed Free Exclusive territory granted to right men-—we run newspaper advertising and arrange for Free in- stallation by competent garages. Printed matter and eards also furnished. We want men in every county who can handle men and sales and make from $3,000 to $15,000 or more according to territory. We have a special Bonus Offer of Syndicate Shares to those who take territory at once. This offer cancels itself when 100,000 fully participating shares are allotted. FREE—One Set. Free Introductory Advertising Offer One set of Detroit Safety Headlight Devices in a neighborhood makes everyone want them. It’s the best kind of advertising for our representatives. There- fore, for a short time we will sell two sets for the price of one ($2.00) or one set at wholesale price of $1.00, postage paid. Buy two sets, sell one easily at $2.00 yours will be free. This offer is open to everyone to advertise the devices. When territory Representatives are appointed offer ceases—so act now. Easily in- stalled by anyone. Get literature— clip FREE coupon, fill in, pin $1 or $2 bills to coupon act quickly NOW. Motor City Syndicate Offices: 1217 Book Bldg., Dept. 42 Detroit, Mich., U. S. A. Motor City Syndicate Offices: 1217 Book Bldg., Dept. 42 | Detroit, Mich. | Gentlemen: Without obligations, please send literature of Detroit Safetv Headlight Devics Send such offer as I have marked below. | Ly ACA RIE TEE EE kc 04 hn RES Kew w cpreid ad waewes 3 Weise COPOPYT 06 ws anevne see ee ba Mee oe ws eee bees Madi oHeN r Make Pe CER 6 0s 4 6640 00 HONS HEWES Model . Year | Make of other car a : Model Year Fill in both for $2.00 offer. | Are you interested in Bonus Offer?........... 0.0. c cece eee eereees , Just use Dollar Bills if sending money | Enclosed $ for ofter as marked above. These to he | mailed postage paid. | PORNO fi sh cca S Sin oop: wana. « ©. e aueve mom Riera doers NE eee oR Re me te eee | Rotates inis kot arta gtx devs ape lag ni ua WU ona Stat...

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] ae

“Sp YANKEE” Bench Drill Does Your Thinking for You — SD

\ ] \ u have To do 1S to set your work and turn the crank. The “Yankee” \utomatic I ric- ti Feed runs drill down to contact. Then the drill is fed i c roper rate a d with the | right pressure, by the “Yankee” — | \utomatic Ratchet Feed. It does away with drill breakage from inaccurate hand-feeding. \utomatic thi ff prevents jamming No. 1005 illustrated two peeds 3 1av cl u } holding drills up to ! inch. Entire ength, 28 inches. No. 1003 one speed; 3-jaw chuck, holding drills up to 14 inch. ITntire length, 1834 inches. Some other “YANKEE” Tools Ratchet Chain Drills Ratchet Tap Wrenches Ratchet Screw-drivers Plain Screw-drivers 1', to 30 in. blades Ratchet Hand Drilis Ratchet Breast Drills Vises, base Bench remov- able Dealers everywhere sell ‘*‘ YANKEE” Tools Write for FREE BOOK North Bros. Mfg. Co. Philadelphia, U.S. A. "YANKEE" TOOLS Make Betlov Mechanica

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

Unique Steam Engine Is Simply Built from Cheap, Easily Obtainable Parts O BUILD a small steam en- gine is the ambition of almost every home worker at some time or other. There is a peculiar fascination aboutengine build- ing, even if the finished model serves for no other purpose than a curiosity or toy, but the majority of amateur mechanics are hampered because of lack of tools and material and the difficulty of making patterns for castings. Here is a model engine, however, that requires no castings and no machine work. It is made mainly from pipe and pipe fittings with a few hand tools that are in almost every home workshop. A bench vise, breast drill, light hammer, a few files, small taps, and small drills are

By Frank N. Coakley cv | flange on each side of the piston to hold the ring in place. Common twine can be used as a packing for the stuffing box The crosshead is made from a piece of brass, 14 by 9/16 by 5/16 in. thick. A 1¢-in. hole is tapped in one side and an- | other 1!¢-in. hole drilled through the side for the connect- ing rod. A groove filed on both sides of the crosshead 3/16 in. wide to receive slides is that are fasten- ed with screws to the center

body of the engine. The center body of engine is made from a piece of 1»- in. pipe, 1% in. long. This pipe is threaded at both ends, and the cyl- inder is connected

Made with hand tools described on this steam engine page, looks necessary, and the parts can be bought cheaply at hardware and ten-cent stores. The cylinder proper is made from a piece of 14-in. pipe, through which a 5¢-in. reamer is run to give a smooth finish. This pipe, which is 15¢ in. long, is tapped for 3y-in. pipe or °4-in. standard plugs at both ends. The pipe plug used as the top cylinder head is filed down to !4 in. in thickness and the square end also is filed down to leave only enough for a wrench hold when removing the top head. The bottom head also is made from a 3¢-in. pipe plug. The square end is removed entirely from this plug and a !,-in. hole drilled %, in. deep and tapped for the stuffing-box gland. The gland and bot- tom head are drilled for a !<-in. piston rod. The piston rod is threaded at each end, one for the crosshead, the other for the piston. The piston is made from a !,-in. length of brass rod 5, in. in diameter. A short length of 1/16-in. fuse wire is used as a piston ring. This allows for a small mainly from pipe and pipe fittings, this small and runs expensive models that can be bought in the large stores w:.th the center body by a !.-in. pipe cap tapped for a 14-in. pipe plug. When as- sembling at this point, care is to be taken that both like one of the parts are properly in line with each other. This center body is provided with two openings opposite each other. They are 7/16 in. wide by 114 in. long and are made by drilling 7/16-in. holes on 13/16 in. centers and filing away intervening metal, preferably with a round file. The crosshead gibs are at right angle to these holes and are held in place by two !,-in. round head machine screws. These side holes are necessary for assembling the gibs, crosshead, piston rod, and con- necting rod. The connecting rod is made from a piece of 5/16-in. square steel 17 in. long. After filing the top or small end to the desired shape, and drilling a 14-in. cross- head pinhole, a saw cut is made about 15in. long. This is done to enable one to spread the ends, so that the connecting rod’s upper end will straddle the cross- head. The lower end is filed to 3/16 in. wide le 5/16 in. thick. Two 3/32-in. are drilled for the connecting-rod rap bolts. The connecting-rod brasses can be made by clamping the pieces of P a and leit holes ol

for bea mu line con ings k hole | and side adv and | sari T rolle diar pin The witl T and allo and spril the hole W ches it. havi one For hole: view in tl bety At betw This the 1 Ju a ho! suit tapp stear Win tapp TI The for t groo W mode engir plete engir How for p now mont

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ilt ts ide of d the ce of ry ath d an- | e side a engine. ar body ; made p of |o- L% in. pipe is t both the cyl- inected center | -in. tapped n. pipe en as- at this is to be t both roperly th each ith two hey are and are mn 13/16 rvening e. The to these ro l¢-in. ese side ling the nd con- from 4a in. long. 1 to the n. cross- je about le one to nnecting 1e cross- in. wide 3/32-in. etin g-rod i brasses pieces of ———————— | from a piece of 114-in. extra-heavy pipe | flange are used for connecting the whole /and 1%-in. holes are drilled through the | side of the plugs to act as oil holes. | sarily, at right angles to the shaft hole. | one side to fit the side of the cylinder. | holes are drilled, as shown in the sectional HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY brass together and drilling a 3/16-in. hole for the crankpin. These brasses are held in place by the connecting-rod straps. The crankease of the engine is made 21/16 in. long. A 1% to 1)4 in. bushing is used as a connection between the center body of the engine and the crankcase. One end of the 114-in. pipe is tapped for the 114-in. bushing, while a standard thread is used for a square 1!4-in. floor flange for the base. The four holes in the with the wooden base. The 114-in. pipe is drilled and tapped 15/16 in. from bottom to center of holes for 3¢-in. pipe plugs. These plugs act as bearings for the crankshaft. Again care must be taken to drill these two holes in line with each other, as it would cause considerable difficulty if these two bear- ings were out of alinement. Each of the 3¢-in. pipe plugs has a 14-in. hole drilled through for the crankshaft, It is advisable to file both ends of plugs smooth and parallel with each other and, neces- Crankshaft and Eccentric The crankshaft is built of 14-in. cold rolled stock and two disks 1 5/16 in. in diameter by 3/16 in. thick. A 3/16-in. pin is riveted between these two disks. The eccentric is fastened to one of them with the high side opposite the crankpin. The eccentric moves the valve rod up and down through a small shoe, which is allowed to ride on the face of the eccentric and is held there by a small compression spring. The \-in. valve rod is bent to the proper angle so as to line up with both holes and is threaded at both ends. While not hard to make, the steam chest has the most work connected with it. The piece next to the cylinder and having the ports is made of brass, filed on For the top and bottom ports two 1/16-in. view. The exhaust port is a 3/16-in. hole in the center of the block, and central between the upper and lower steam ports. At least 14 in. of metal is to be left between the steam and exhaust ports. This distance governs the stroke length of the valve rod. The center section of the steam chest is ahollowed out piece of brass of a size to suit the cylinder section. A hole is tapped on the upper side for a -in. steam pipe. The lower side is - drilled 's in. for the valve rod and drilled and tapped for the valve rod stuffing box. The flywheel is 3 or 314 in. in diameter. The wheel from an old valve can be used for this purpose. The pulley can be either grooved or plain, about 1 in. in diameter. When assembled and adjusted, this model is a husky 54 by % in. steam | engine and, for its efficiency and com- pleteness, perhaps the cheapest small | | engine that can be built. How to make an especially fine table for playing the fascinating Chinese games how so popular will be told in next month’s Home Workshop. To locate the trouble —use your flashlight! Use your flash- Keep an Eveready at Tie a tape around it and hang where it will be instantly convenient. Use it for safe steps in the emergency and all the time. No fire hazard. Don’t fumble—keep an Eveready Flashlight in your room. Another in your garage for looking over the car at night— and use on the road. Keep all your flashlights loaded with Eveready Unit Cells and you will have plenty of bright, LIGHTS out—something wrong! light to locate the trouble. the top of the cellar stairs. white light when and where you need it. If you have a flashlight not in use, get it out and reload with Eveready Unit Cells; long-lived cartridges of brilliant light. Buy them from any electrical or hardware dealer, drug, sporting goods or general store, garage or auto accessory shop. When you buy new flashlights, be sure they have EVEREADY stamped on the end. EverREADY means the highest standard of flashlight quality, and Eveready Unit Cells give more light longer. Prices from 65c to $4.50 complete with battery —anywhere in the U. s. A. NATIONAL CARBON CoMPANY, INC., New York, San Francisco Canadian National Carbon Co., Limited. Fact oryand Offices: Toronto,Ont. EVEREADY FLASH LIGHTS iy BATTERIES ~-they last longer No. 2692 Ever: two-cell 109 rdy alu mint flashlight compli te with battery 75c— anywhere in U. S&S Ae EVEREAD UNIT CEL! | | >I A F ee LASHLIGHTS — —— ®NAL CARBON © iW voen » * a EvergADY Uwnir CELLS make all flashlights better. Eveready Unit Cells fit and improve all makes of flashlights. Eveready Unit Cells come in two sizes to fit every tubular case flashlight. Know the Eveready size that fits your case. Then you can buy new Eveready Unit Cells without bothering to take your flashlight along Eveready Unit Cells mean brighter flash lights and longer bat- tery life. the

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110 The cross-gram cut 15 the test that proves this plane’s mettle HE Sargent Auto-Set Bench Plane has a reputation for coming through the thousand odd jobs that develop at a busy work bench, without a murmur or a moment’s hesitation. Its unusual cutting keenness— across or against as well as with the grain—will surprise you. Its all around dependability and sim- plicity of adjustment have gained for it, everywhere, that real affection which craftsmen feel toward tools which never fail them. SARGENT Auto-Set Bench Plane SARGENT Steel Block Plane The auto-set feature permits the removal, whetting and re- placement of the chromium steel cutter in the shortest possible time. Furthermore, in doing this it is not necessary to change the original adjustments. Ask your hardware dealer to show you the Sargent Auto-Set and the Sargent Steel Block Plane for smaller jobs. You'll find they are made of lasting ma- terials, perfectly fashioned and finely finished. Both are worth having. Drop us a post card for the Sargent Book of Planes, which contains detailed information concerning them. SARGENT & COMPANY, Hardware Manufacturers 50 Water Street, New Haven, Conn. SARG. a NE Jools & } far dware 5 A Gerstner CHEST is valuable to MACHINISTS and Saw Filing Pays Buy a Foley Saw Filer and ‘*Five-in-One”’ ade of alu m white ¢ ellulc vid. e ved and ado spted by colle thIn tions, $1.50 o athe Tr ‘ 4 Catalogue Free Gilson Slide Rule Co. .Niles,Mich. a1. Patente TOOLMAKERS 25, dependent, profiable business € Os yrite today for Catal revi a a Pig mm Territory open to pte cman od it saves from loss and ( parties. damage. Write for free { FOLEY SAW TOOL co catalog. - 3613 Portland Avenue H. GERSTNER & SONS 502 Columbia St., Dayton, 0. COEEAPOLTS, ONIN. ” Te %, “WONDER” COLD PIPE, idge "One’” Slide Rule = \ss>r> > TUBING & BAR BENDERS Standard of the World HAND and MOTOR Sreeatee 14 Sizes of Machin What it costs to bend «it our way. Per bend. 1’’ pipe 5 cents 4°" pipe 25 cents 2'’ pipe 10 cents 6 pipe 60 cents 8'’ pipe $1.00 Send for Catalogue. AMERICAN re BENDING MACHINE CO. 51 Peart St. Year to Pay Boston, Mass. | 90 volts. HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Making the Loudspeaker Talk Up with Two-Stage Amplifier (Continued from page 84) wire to connect terminal F, of socket k with the wire just mentioned. One terminal of condenser D is con- nected with the wire connected with post A and the other terminal of the condenser connected with the wire connected with post O. A wire is next used to connect post P | with the No. 2 terminal of rheostat H and the No. 1 terminal of rheostat J. The No. 1 terminal of rheostat H js then connected with the F, terminal of socket F, while the No. 2 terminal of rheostat J is connected with the F, ter- minal of socket K. The G terminal of transformer C connected with the G is then terminal of socket F, while the F terminal of the transformer | is connected with binding post Q. Next connect the top outside spring of | jack G with the P terminal of socket F; | the inside spring, which makes contact with this outside spring, with the P ter- minal of transformer J; side spring with binding post R; and the the bottom out- | inside spring, which makes contact with | the bottom spring, with the B terminal | of the transformer. Final Connections and Batteries Now connect the G terminal of trans- | former J with the G terminal of socket K. The F terminal of the transformer is then connected with post S. The P terminal of socket K is connected with the top outside spring of jack L. The inside spring, which makes contact with the top spring, is connected with binding post M. ; The bottom outside spring of the jack is connected with binding post 7’, while the inside spring, which makes contact with the bottom spring, is connected with binding post N. The batteries are easily connected. The positive of the A and the positive of the C batteries are connected with binding post O. The negative of the A battery is con- nected with binding post P. Leads from binding posts R and T are tried on various taps of the B battery, varying from 45 to | 90 volts, until best results are obtained. Leads from binding posts Q and S are tried on various negative taps of the C battery until the best values have been obtained. Although good results can be obtained even though the values of C and B bat- teries are not absolutely correct, best re- sults are obtained only when these v values are just right. It will pay in the long run to spend some time in trying various combinations until best results are obtained. The A battery used will, of course, de- pend on the type of tubes used. The total value of the B battery used for both the detector and amplifier should not exceed The C battery should have value of about 7 volts. The tapped por- tion of a small B battery will usually do very well. The positive 22 14-volt terminal is used as the positive terminal of the battery, while the taps are used as the negative taps. strik strai tend such will spee | a col alat mak % il 20-g lin. W | spine | grinc | sligh slots back Tl dam or pi Da F } & with mete tell amp: dry tach to it ing aga bind the a illus’ A regis 18 { pere: Cells only conn and how five | Ay. l pa and Two atel; —

Page 87

kUp. i cet Kk con- l post lenser with ost P T and | H is nal of 1al of ’ 2 ter- Ss then | socket | ormer | ‘ing of | ket F; | ontact | P ter- n out- | nd the | t with | rminal | ries | trans- | ket K. is then nected 1. The t with inding e jack | | while ontact d with d. The | f the C 1g post is con- | ls from | various | n 45 to | tained. | S are | the C | re been | otained B bat- rest re- values 1d some is until rse, de- he total oth the exceed | have a ed por- tally do is used patter). ive taps. Hurling Ice Comet Is Novel Sport for Skaters We this ice comet is swung on the end of a rope and released, it | strikes the ice and scoots away in a straight line on two of the fins. tended to be aimed at a suitable target, such as a pumpkin. Over smooth ice it will travel several hundred feet at great speed. Cut the hardwood spindle 7 in. long and 2'5 in. in diameter, and taper one end to The completed ice comet (at left) and method of sawing the fins or runners from sheet steel (below) | aconical point, which can best be done on |alathe. Then grip the wood in a vise and make four saw cuts parallel with the axis 14 in. deep and equally spaced. From 20-gage sheet steel, cut four fins, each 11% | in. wide and 1 in. less in length than the ispindle. The front ends are curved on a grinder. Then the long edges are chipped slightly with a chisel and driven into the slots. A large screweye is turned in the back end for fastening the rope. The wood should be protected from dampness by two coats of shellac, varnish, or paint. —D. V. H. Dashboard Ammeter Is Useful for Testing Dry Cells g YOU havea fj car equipped : with a dash am- meter, you can tell the exact amperage of a dry cell by at- taching wires to it and hold- ing their ends |against the binding posts of the ammeter, as illustrated. A cell that registers from 18 to 30 am- peres is good. Cells that give connect with new cells, can be connected and used in an emergency. One dead cell, however, will reduce the current in the five good cells to next to nothing. A VARNISH for wallpaper can be made of 1 part borax, 1 part flake white shellac, and 20 parts alcohol by weight, strained. Two coats will make the paper moder- ately washable. It is in- | § only five or 10, while not good enough to HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Et 111 Is There Such a Thing Asa 100 Percent Perfect Chisel? HERE IS. We can make A 00 percent perfect chisels for cutting lead, concrete, nickel, steel, cast iron or anything else if we know in advance to what use the tool will be put. To make an all-purpose Chisel, however, we must secure a per- fect “average temper” at the cutting edge so that it will cut all materials exceptionally well, without dulling too quickly. This we have accomplished through the Vichek Process of tempering Vanadium alloy steel of a spec- ial analysis. The Chisel edge has extraor- Vichek tem- pering is neither too hard to dinary resistance. cause chipping or too soft to allow the edge to turn. In Vichek Chisels up to seven- sixteenth inchstock sizewe increase the size of the cutting edge by one-sixteenth of an inch, and in those from one-half inch to one inch stock, by one-eighth of an inch—added strength; greater cutting surface. Vichek Cold Chisels are splen- didly proportioned. With relation to size of stock, cutting edge and length, they are in correct balance. All Vichek Tools are designed and made as carefully as our Cold Chisels, of the finest steel. They are tools of tremendous vitality, which means long life. THE VLCHEK TOOL COMPANY, CLEVELAND, OHIO EASY TO SAY VELCHEK VLCHEK TOOLS __ MADE BY THE WORLDS LARGEST PRODUCERS OF TOOL KITS - “Experiments With 110-Volt Alternating Current’’ | ERE at last is a book that gives a practical working knowledge of the alternating current. The only way to gain a thorough understanding of electricity is by direct personal experiment. How | a practical knowledge of the alternating current can be gained in an interesting and inexpensive way is shown. The knowledge that comes from experiment is of vastly more value than that acquired from the performance of the stereotyped series of battery ex- periments usually described in books on Alternating Current. 256 pages, 135 illustrations. Price, postpaid, $1.75 | POPULAR SCIENCE MONTHLY 225 West 39th Street New York City How To Make Things Electrical Have the fun of doing it your- | self and save half the cost This book gives directions for making hundreds of electrical appliances and devices for the home, the shop and the garage. The simple directions and many drawings make the work easy. 429 pp. Price, $1.50 postpaid POPULAR SCIENCE MONTHLY | 225 West 39th Street, New York City

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1i2 HOME WORKSHOP DEPARTMENT OF I OFULAR SCIENCE MONTHLY

Decorative Weatk »--Vanes MAKE MORE BONES ¢ that Tella. sry | By Ernest Bade, Ph.D. PROFIT IN 4 MONTHS! V EATHER-VANES may often tell a story in addition to the direction of the wind. For instance, a hunter might have a flock of geese flying over his house, a sailor, a metal ship upon a metal ocean,

Atkins *‘Non-Breakable’’ Hack Saw Blades

EORGE ALEXANDER of Pennsylvania made $3000.00 in 4¢menths making and selling CRISPETTES with this outfit. (Nov. 7th, 1923), Jacob Gordon, New Jersey, (November 2nd, 1923 says: ‘Profits over $4000.00 in 2 months’’! Mesner of Baltimore $250.00, in one day! M. L. Cronen, Ohio, (November 3rd, 1923), writes: “*Doing big business—sold over 200,000 packages Crispettes last year’’. Mrs. Lane, Pittsburgh, says: “Sold 8,00 packages in ONE day’”’. We Start You In Business Crispettes easy to make, easy to sell. We furnish everything — complete outfit, secret formulas, raw materials, full directions, wrappers, etc. No expe- rience needed. Little capital starts you on road to wealth. Open a retail store of your own. Sel] wholesale to groceries, drug stores, etc.

66. Best Blade After being cut out with 99 a chisel, the ver Sse ornamental vane is piv- oted on an Build a Business of Your Own

' , , = : | Crispettes sell fast everywhere. Everybody likes Phat’s what you'll say if you'll try iron rod so | | them. They’re a delicious confection. We'll tell \tkins ‘‘Non-Breakable’”’ Blade in that it will | you how to build a business of your own. Start vour hack saw frame, next time you swing freely now, in your Lown. . . : in the wind have a difficult job of metal cutting. With these blades you can cut faster Profit $1,000 a Month Easily Possible

, Send for illustrated BOOK OF FACTS. Tells how and easier, and avoid blade breakage. many people in small towns and big cities are mak hey -e de of speck + celecte ‘ ancier. ¢ c nti be eee ing big successes of Crispette Business. on hae, Phe y are made of specially elect d a dog fanc ier, a dog pointing to the w ind, ns oc paca Ange “abs ger pewe hae aeay steel and tempered by an exclusive or, as illustrated, a setter flushing a bird. mation. It’s FREE. Write now. Postal brings it gas and oil process which gives them Such weather-vanes are easily made i a harder, keener cutting edge and a from thin sheet tin. zinc. or iron. First LONG EAKINS COMPANY 4 tougher. more flexible back. That’s e 4 . . . 7 247 HIGH STREET SPRINGFIELD, OHIO : igs api — draw the silhouette of the desired design -| y the reason these blades have greater upon paper and transfer it to the metal ; : 0 aper an “anster UE cutting capacity, hold their edge Peart ¢ . . ! shop information, Every ay tie ay holes are drilled or punched in these so i? rd 5 NOV ™ ' — m ie: piu that the whole will pivot easily on a strong Je or 1 ° V1 your . : ee ier epries iron rod. The rod is fastened to the roof name and address on the margin of é thi , il j or some support exposed to the wind. Executive Accountants command big salaries. Thousands of fir this page and mail it to us. WI ; . } need them. BS eg Boo ee U.S. ei > > Tes y= é =) as Le are earn ni ra o oro Ms ! nen t u¢ W eat 1er-vane as yeen ss raing $3.0 ° gi ee a vom. | ve t ein yout mecoupting poe E. C. ATKINS & CO., Inc. mounted, it is advisable to clamp another | Epa tain genic } c troller and Instructor, University o yiece of metal around the rod to represent | aiso former Director of the Illi fC. P. A of the Dept. D-20, INDIANAPOLIS, IND. I 1 | ] tt N TI I t | National Association of Cost Accountants” He js aosiated by 2 a eer 4 ¢ ¢ 7 € > > > € | ff « < ’s c netitu @ Makers of Silver Steel Saws and Tools an arrow anc . ac c er 4 ‘. nis par | Toecanans. Low tuition les—aaey eoalkey Write now forinformati (¢ ontin ued on page 113 ) LaSalle Extension University Dept. 283- H, Chicag4 = The Largest Business Training Institution in the Worl

114 HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

Page 89

- ge a 1ia made isell ng » 192 3), id, 1923), Mesner Cronen, Yoing big ettes last old 8,000 s 'e furnish ulas, raw No expe- m road to wn. Sell wn ody likes We'll tell wn. Start Possible Tells how *s are mak- hows how, able infor- | brings it it. PANY D, OHIO finished che estnut -16, and 1-2” amer wrench. — e thread is U.S.S tavery low figure atisfied custome: istrating our fu Ss oe. fass., U.S.A. of teachin vill give tree ae iitar, Banjo, Man- Jan jo- Guitar abs0- small charge for ; vel No obligation St., Chicago, tl gps PERT AN of fi Thonsande, {= u ae Ee mai! ! ve accounting poe begin. zd c or Castenholz oe “ity ‘of Mlinois) nd 0 assis b : nerican Institute @ now forinformat™. 283-H, Chic on in ‘the World Sak Made to Be Beaten! That’s what production-rec- ords are mostly for—to step- ahead and improve on. The records of Veeder Count- ers say “Come on!’’ to thema- chine operator. They impel him toscore, and score higher ! It’s the same when developing a machine: the best record to date becomes merely a rec- ord to beat—when your gains register on a COUNTER The Set-Back Rotary Ratchet Counter below is for machines such as presses and metal-stamping machines, where a reciprocating movement indicates an operation. Registers one for each throw of the lever and sets back to zero from any figure by turning knob once round. Supplied with from four to ten figure-wheels, as_re- quired. Price with four figures, as illus- trated, $11.50—subject to discount. (Cut less than 1% size.) Set-back Revclution Counter of similar model, $10.00 (list). Speed Counter 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 !5 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 you’d like to see—and maybe apply. The Veeder Mfg.Co., 44 Sargeant St., Hartford, Conn. HOME WORKSHOP DEPARTMENT OF POPTI AR COCIFNGCE VWONTUDIV need entire length of the the arrow points toward the north. Strong Folding Chair Made with completely wrecks camping chairs. | braces between the seat and the legs Mak: ( inued from page 112 be 4 Decorative Vanes only small, one eighth of the | vane being sufficient. It should be so attached to the rod that Framework of Band Iron N AUTO and camping trips, I find | useful the collapsible chair illus- trated. Although it weighs only 5 lbs., it will sustain about 300 lbs. and is sturdy enough to stand the abuse that so often The The completed chair and sectional view showing dimensions and method of folding details of construction are made the illustration. The tie rods are !{ in. The are pivoted to the seat frame by means of 14 by 34 in. cap screws, riveted for a loose fit. The back and seat are made of 14 by 2 in. slats fastened to °4-in. strips on each side. The arrows show’ how the folds. in diameter. seat Tilting Shelf for Oilcan CONVENIENT rack for “ tainers can be made by fastening the can crate on a diagonal piece in the corner of the garage, thus keeping it out of the way and facili- tating pouring the oil. The crate bottom hinged to crosspiece that the center of the can will be situated nearer the cor- ner. This will cause the can to rest against the wall when not in use and yet allow it to be tipped forward with one hand, while the other holds the measure, If a crate is not available, to fit the can. is the sO To pour oil, the can is swung forward WHEN the pivot bolt of an iron pump or the pins of a door hinge become loose, it is advisable to try giving them a half some, turn. This will usually take out it not most, of the play.-—L. M. clear in HOME WORKSHOP DEPARYMENT OF POPULAR SCIENCE MONTHLY oil con- | one can be made | roune PRENTISS VISE ERE’S just the tool vou need for your work bench during winter months—a Prentiss Vise \ll those little iobs VO have been planning to do will be easier when you have this handy tool Its strong jaws, deeply serrated, will hold objects of any shape, or size The jaw faces are interchange ible, and when worn may be re hewe¢ d in a lew me ments The Prentiss Bull Dog Vise has swivel base, enabling you to turn your work at any angle—a great convenience for working in small space. See a Prentiss Vise at yout hardware dealer's on a_ display stand. If he doesn’t have them in stock fill in the coupon and mail today. PRENTISS VISE COMPANY 106-110 Lafayette St., New York City ~ Patent Self Adjusting Jaw | lesigned to hold pieces of ay hape Prenti | Prentiss Vise Company 106-110 Lafayette St., New York City Please tell me the name f t nearest

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HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

114 Now for the hook-up HE radio set builder's eves Celoron, a bakelite product, has shine with pride as he inspects high dielectric strength. It is ap- his drilled Celoron panel. He has proved by the U. S. Navy Depart- done a good job. The finely fin- ment Bureau of Engineering and ished Celoron panel reflects his the U.S. Signal Corps. good workmanship. He is ready to Special-sized Celoron panels are mount his instruments and make cyt to order from sheet Celoron. the final connections. Standard Celoron panels come cut A Celoron panel insures good — and trimmed, ready to use, in these looks to the radio set. Celoron — sizes: panels are finished in black, oak and mahogany. Each Celoron 4 ox > - 6 pe As x 3/16 panel is wrapped in a dust-proof 3 _ 12 “i Ay: 7 j ol - y + glassine envelope to protect its 4—7x14x316 8—12x 18x 3/16 lustrous surface. Grit can not 9—7 x 26 x 3/16 scratch it. Hands can not finger- ° ° , Write for « i ‘resting OOK LE “Gel- print it. You are the first to un- Heaing Pea "Right Ho a aca ot ut ‘ . y the gn OOR- < ye ree Wrap It. upon request. To radio dealers: Send for special dealer price list showing standard assortments Diamond State Fibre Company BRIDGEPORT (near Philadelphia) PENNSYLVANIA Offices in Principal Cities In Canada: Diamond State Fibre Company of Canada, Limited, 245 Carlaw Avenue, Toronto ( ’ CONDENSITE N

the theory and design of amateur wireless transmitters and receivers, the construc- tion of transformers, high voltage con- densers, spark gaps, aerials, masts, and receiving sets for long and short wave receptions. 330 pp. Fully illustrated Price $2.25. POPULAR SCIENCE MONTHLY 225 West 39th Street, New York City The Wireless Experimenter’s Manual E. E. Bucher HIS book thoroughly covers the entire field of amateur radio work, including

Practical Amateur Wireless Stations This book contains best sugges- tions of thirty-three experiment- ers on building, installing and op- erating experimental stations for radio communication. Profusely illustrated. 137 pp. PRICE 75c¢ POPULAR SCIENCE MONTHLY 225 West 39th St., New York City, N. Y.

| Unique Plant Stand Has Trellis | | | | |

Support for Bird Cage By_Stacy E. Matthews NE of the pieces in a dining-room set I recently built for my home is the three-in-one plant stand illustrated. It is distinguished from the average flower box by the trellis work and hanging bird cage, and yet, with all its novelty, it is not difficult or expensive to construct. The materials, which cost me about $3, are as follows: 1 pe. 14% by 10 in. by 29 in. white pine, clear 1 pe. % by 91% in. by 8 ft. white pine. seconds 1 pe. % by 12 in. by 3 ft. 1 in. white pine, seconds 1 pe. % in. by 10 ft. 2 in. band iron 47 lineal ft. % by % in. redwood strips 8 lineal ft. 4% by 1% in. strips, any wood 4 14 by 1% in. carriage bolts 20 3/16 by % in. stove bolts 1 pt. paint any color desired First rip the four posts 144 by 15¢ by | 29 in. and dress them to 11% in. square.

Much as it differs from the conventional plant stand, this attractive piece of fur- niture is easily and _ cheaply made Lay them off in pairs to be plowed—!, | by 1% in.—for the sides and ends. After | plowing, taper the posts on the inside | edges only from the bottom of the | plowed groove to 1 by 1 in. square at the | lower ends. Next, cut the two side panels, 91% in. wide, 36 in. long at the bottom, and 35 in. long at the top, and the two ends, which are 91% by 12in. The bottom, 14 by 12 by 36 in., must be cut out for the | posts at each corner and fitted in from underneath. Then the 4 by 14 in. strips are fastened with finishing nails to hold up the bottom. The foundation for the lattice-work is | the strip of band iron. Beginning near each end, drill a series of 3/16 in. equally spaced holes about 7 in. apart. Then after fastening one end in the box, gradually spring the other until it is arch shaped and bolt the second end in place. Next bolt a pair of 4 by % by 14 in. red- wood, cedar, or cypress strips to each of the remaining holes in the band iron. The first pairs of strips will probably have to be specially fitted in the box. The out- side ends of the strips are finally bolted together to form a diamond design. The (Continued on page 115) oe

be | Oil | th ch ror an | Mm co &@ fF wet &A

Page 91

Allis n set s the It lower + bird it is ict. ut $3, —— lear onds seconds

ational of fur- made wed—!» | s. After | 1e inside | of the | re at the le panels, bottom, the two 2 bottom, | ut for the | in from | in. strips s to hold e-work is ning near 1. equally rt. Then the box, it is arch | in place. 14 in. red- ‘o each of and iron. ably have The out- lly bolted sign. The )

memes | | | | | | | | | HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

Unique Plant Stand (Continued from page 114) spring for the bird cage is fastened to the central point of the lattice-work. Several coats of paint should be given and for best results the last coat should WOODEN STRIPS e Ae Va" X 778K 14" ~sQ BAND ane Yo'x4'x2-

| / PANELS | V2" THICK BOTTOM % THICK |» '4"x 12" CARRIAGE BOLTS ae —— 3'- >" Details and dimensions of the flower box and trellis, which cost about $3 be well rubbed with pumice-stone and oil. The floral spray is a painted motive that appears on the buffet, serving-table, china closet, and tea wagon of the dining- room set. A central stenciled ornament and plain line border would perhaps be more effective for general use.

Complete List of Blueprints NY one of the blueprints listed below can be obtained from POPULAR SCIENCE MONTHLY for 25 cents. The Editor will be glad to pro- vide, upon request, information rela- tive to tools, material, or equipment. Blueprint Service Dept. Popular Science Monthly 225 West 39th St., New York GENTLEMEN: Send me the blueprint,or blueprints, I have checked below, for which I in-

GLOBE... <.. .: cents in stamps or coin: No. Title Price jg ae 25e C 2. Smoking Cabinet..... ....... pe 3. Book Trough End Table......25¢ O 5. maccmen Cabinet... . oc. esc 25c 6. V. T. Radio Receiving Set..... 25c ee ae. 25c #9 9. Arbor with Gate and Seats..... aoc. tC) ee 5c O 11. Bench and Tilt- Top Table..... 25¢ 12. Electric Washing Machine..... asc 6) RSs RUN ak ei eet ethled 6 eo '0 25c 14. Toy Train, Horse, and House. .25c_ | 15. Home Workshop Bench...... 5c 16. Inlaid Radio Cabinet. ase. { 17. Cedar and Mahogany Chest...25c | 18. Telephone Table and Stool.....25c 19. Grandfather’s Clock. <ewseee. bl 20. Wimt TO BGK... ccc ee ccs 25c O 21. Colonial Writing Desk........ 25e 22. Girl’s Cabinet and Desk....... 25c 23. Pergola Garage.............. 25¢ (] 24. Gateleg Table eect 25. Sailing Outfit for Canoe..... 25c 26. Baby’s Crib and Play Pen.....25c 27. Kitchen Cabinet Work Table... 25c 28. Pullman Play Table 7 ade 29. Toy Tea Cart, Garage. etc. ....25c 30. Tool Cabinet, Bench Hook, etc. 25c 31. Priscilla Sewing Cabinets 25¢ LES et aA ae ORD Poe Oe Bae MEM REET ame eer (Please print) RE FSACAONG baila paver a avauy ie aloes iaieiand es Gis baa eee

115

Ousitier Ducon Socket Plug DusiLieR MiCADON ‘The Standard Fixed Condenser\ _

DusBitiER VARIADON Variable Mica Condenser SO convenient The Dubiler Ducon is the stand- ard socket-plug. It takes the place of the cumbrous, unsightly antenna. Simply Screw the Ducon in any lamp-socket and connect it with the radio set. Not only are the broad- casting stations heard clearly, but tuning 1S sharper. Dubilier Condenser and Radio Corporation 48-50 West Fourth Street New York

Dusiier DuraTRan Radio Frequency Transformer

TWENTIETH CENTURY Book of Recipes, Formulas and Processes This book of 800 pass is the A mine of informat up-to- most complete Box f Rec pes date in every respect Con- ever published Hints He Ip tail al mmense imber of Practical Ideas and Secret Pr rmulas that ¢ ! ought esses covering every branch f | to have that are not found the useful arts are given. | other work. Price, $4. 00 Popular Science Monthly, 225 W. 39th St., New York

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HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

HEAP FUEL Burn NurGas — ’

Stove [| iea an ed =, No More a twist of Coal Bills |=

—No Wood Chopping =< No Dirt or Drudgery P-TO-DATE homes are being built without coal bins. There’s an easier, cleaner, better way to cook, heat and bake. Slips into any heater or range in a jiffy A simple little device known as ‘‘NU-HEAT’”’ that slips ina jiffy into any stove, heater or range, takes one part of coal oil (kerosene) and mixes it with twenty parts of free air. This makes ‘‘NU-GAS,”’ a cheaper gas than city gas. Has twice the heat of coal. A Warm House On Arising Don’t shiver on cold mornings while building a fire. All you do is turn a tap—you have intense, glowing cheerful heat almost instantly. Warms coldest rooms in few minutes. As much heat as you need on ‘‘blizzardy’’ days, or just enough to be comfortable on milder days. Better Cooking and Baking Coal and wood A heat are never (, steady.Oventem- _/ perature is con- | gtantly changing. That ruins many a baking. But the new method gives you steady, even, dependable heat ALL THE TIME. As much or as little as you need. 30 Days’ Free Trial Absolutely safe. And anironclad guar- antee insures that you’ll be delighted with this freedom from coal drudgery— this clean, economical way to cook, heat and bake. And you may have one of these devices on 30 days’ free trial. Information Free? Investigate this remarkable new way tosavecoal bills—get better baking results—cut housework in half, and have the warmest, cleanest, coziest home in town. Just say ‘‘send

AGENTS Drop everything for this amazing money- maker. Every woman wants one as soon as she hears the low price. Make $50 to $200 a week full or spare time. Ask information free.’’ Special In- about ‘‘agents “pro. troductory low price offer if you | Position.’” Our per : en sonal co-operation, write at once. Mention if you have heater, range, furnace. Send coupon or postcard today. Wade Hill Mfg. Company Dept, B-41, St. Louis, Mo. Saeseseeane WADE HILL MEG. CO. Dept. B-41, St. Louis, Mo. Send me information showing how NU-HEAT operates and why it is the latest, best and cheapest of all gas-making devices. Explain Special Intro- ductory Low Price Offer. protected territory and free sample case offer,

I have Heater ( ) Range ( ) Furnace ( ) a a aes se ae me Ea |

A Golden Rule Insures Your Success with Tools TY UNTO your tools as you would have done unto you, if you were a tool. This is the golden rule as applied to tools. It also can be applied with good effect in the Chinese or negative form, “‘do not unto others,’”’ and so on. Proper cleaning and _ lubrication, to- gether with correct sharpening and re- pairing, always pay. One of the most important tools used in the home or shop is the hammer. How

CORRECT ANGLE RIGHT SHAPE AND LENGTH BAD SHAPE AND E| JOO SHORT

Handles must be fitted to hammer heads at a slight angle, as shown, somewhat exag- gerated in the upper drawing does our rule apply to the hammer? Well, use it as it should be used, always hitting with the head and never the side. Keep a good strong handle in the ham- mer, and never use a hammer with a cracked handle. The handle should be of the proper shape and length. To have a hammer in perfect balance, insert the handle so that

the central axis through the head stands | at a slight angle to the vertical axis of the handle, with the driving head a trifle low. If a handle is inserted in a reverse fashion, with the head standing high, it will be awkward to use and handle. This is illustrated somewhat exaggeratedly for the sake of clearness. If a hammer face chips, have it annealed slightly. A hammer that chips is dan- gerous to use, and if the chips are large and deep, discard the hammer altogether. Many a weary back and arm can be spared if the saws are kept well set and sharp. Lack of a saw set is no excuse for | not setting the teeth of an otherwise good

a = STRAIGHT PEEN HAMMER —_— Using a flat spot on the rear vise jaw as an anvil for setting the teeth of a dull saw saw, because the top of your vise will serve as a place to set your saw. rear jaw, where the straight, flat surface verges into the radius of the rear sloping surface, file a small flat, as illustrated. This flat should be at an angle of from 5 to 7 degrees. Lay the saw on the vise jaws (Continued on page 117) On the |

GET A HOBBY MAKE MODELS Start a Home Workshop ‘‘Model Making,”’ by R. F. Yates, de- scribes the construction of gas-model engines, steam-engines, locomotives, boats, dynamos, turbines, railroads, guns, etc. Thirty chap- ters are devoted to models of various nature. It will help you to become a better me- chanic. It will help you to do hard soldering, soft soldering, lathe work, tempering, drilling, pattern-making, etc. This is a book every amateur or professional mechanic and model maker should have. *‘Model Making”’ describes real engineering models, not toys. 400 Pages, 300 Illustrations. complete, easily understood. paid, $3.00. Popular Science Monthly 225 West 39th Street New York Practical, Price, Post-

OFT |BROS.& CO. £858 | | Cash or Credit © We import Diamonds direct from Europe and sell direct 4 mail—a great egy to you. SEND H| FOR CATALOG. very thing: oy explained. Over 2,000 illustrations. CREDIT TERMS on ali ¥ : One-fifth down, balance divided into ayments within eight months. e is Gorved tion’’ Diamond Ring illustrated is Solid 14-K Green Gold, Dia- »mond set in White Gold. Bridal Blossom design. Wedding Rings to match. . I 18-K Solid WhiteGold, 17Jewels, $29.75 y Ie KSolidWhiteGold. 15Jewels $24.85

Easy Terms on best engine built. Burns kerosene,distillate, gasoline or gas. Change ower at will. Equipped with the famous WICO agneto. Other sizes, 2 to 25 H-P.—all styles. F RR E E + Write today for my Big Engine Book -"Sent free—No obligation on your part WITTE ENGINE WORKS * 2221 Oakiand Avenue, - KANSAS CITY, MO. 2221 Empire Building, - PITTSBURGH, PA. ARITHMETIC oF ELECTRICITY A practical treatise on electrical calculations of all kinds reduced to a series of rules, all of the simplest forms, and involving only ordinary arithmetic. 200 pp. Price, $1.50. POPULAR SCIENCE MONTHLY 225 W. 39th St. :: :: NEW YORK

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de- yines,

:mos, ‘hhap- ture. me- ‘ring, ling, ional ‘ering ‘tical, Post- ily , York

vided into mond Ring zold, Dia- | Blossom con 9 s. Change us WICO yles. gine Book. your part. ¢ Te ITY, MO. RGH, PA. RICITY ge ee 50. NTHLY y YORK

HOME WORKSHOP DEPARTMENT UF fOPULAR SCIENCE MONTHLY

Golden Rule Insures Success (Continued from page 116) and with a straight peen hammer, peen each alternate tooth to the bevel of the filed spot. Turn the saw around and repeat the process on the remaining

straight teeth. If carried out carefully, this little trick will enable one to make a good job of setting saws, although it is | easier for an amateur to use a regular saw set if one is available. Before jamming your saw through an old piece of lumber, look the piece over to | see whether there are any nails or screws

| irons. hidden beneath the surface. If you do hit a nail, stop immediately, to save the saw teeth. Turn the piece around and saw the remaining distance nearly through from the other side. Keep your plane irons sharp, and when grinding them do not try to hurry the job by robbing them of clearance. An iron to be ground properly must have a fairly

_— STEADYING

SINGLE END WRENCH

PROPERLY ars IMPROPERLY [CZ Using single-end wrench when tapping in a tight place and sharpening planes and chisels

long, thin edge. A hurried job will result in a blunt, thick edge, which will not cut freely. If a plane blade is nicked by coming in contact with metal, it will leave a raised line on the finished work, and therefore should be reground at once. Chisels should be ground like plane They should never be used to open tin boxes, scrape off paint, and other jobs that dull the cutting edge. When « bit hits a nail or screw, one or more of its three main parts are affected: The lips are burred, the cutting edges dulled, or the center feed screw ruined. While it is possible at times to fix up a ruined bit with a file, it usually will nct function as it should. Use caution and examine the wood carefully before sinking a bit into it. When driliing the harder metals, such as steel and cast iron, stop immediately when the drill starts to squeak or smoke excessively. If one persists in forcing a smoking and squeaking drill through a hard piece of metal, the result will be a burnt-up drill. At the first sign of a drill’s becoming dull, remove and resharpen it; then reduce the speed of the drill press and jack up the feed. This is done to get under the glazed surface at the bottom of | the drilled hole; that done, the remainder of the hole can be finished as usual. , When cutting scale either on cast iron | (Continued on page 118)

Only 50 days Between You and Big IV in AUTOMOTIVE ELEC Come to Chicago or Train at Home for this New Field that covers 78% of AUTOMOBILE TROUBLES

‘ ¥) ey Four Times His Former Salary **I was making $40 a week as Head Bookkeeper when I took up your training. Last week I made $175 and hardly a week passes in which f don’t make at least $160. No labor either. I locate the trouble and the

117

mey

Makes $1000 a Menth ‘I trained with you 7 weeks, Then I —— os right to work with a big gara Averaged abou $150 a week. After 8 weeks opened my own shop, Find it eisy to get any price I choose to

mechanics do the work. eam Cleariag oree C18 Gs **HENRY L, LUDLOW, Indiana’’ **w. C. ELLERD, Neb.** OU’'’D probably be willing to take a four year bookkeeving job into an income of $175 a week college course if you could earn $132.00 a week as Automotive Electrical Expert; when fellows when through. But you don’t have to. FOR who want to be their own boss, like Ellerd, clean YOU CAN BE READY IN FIFTY DAYS to earn up $1000 a month; everybody simply HAS to that much and more, just like any number of my agree that Ambu Training can't be beat Get my former students are doing. Get my book that gives book and see the proof. the facts and figures. Big Jobs Onen Get Out of ihe Grease d , I know w hi it a demand t for my graduates. This fascinating new profession is clamoring for men, I know what remarkable earnings they are mak- Garage and Repair Shop Owners can get all the ing. I know how employers are glad to get their ordinary mechanics they need. services. Ihave hundreds of letters Mechanics can learn in a shop, but that show how Ambu_ graduates Auto-Electrical Experts are studyv- QUALIFY “make good.” I'll send you copies trained. That’s why shops can’t get of them; tell you to write these the man who knows automobile For One of These fc rm er pupil let them tell you electricity. And yet they have to a what a fas iting, easy polennes have him. Auto-owners will no Big Pay Jobs it is. In free book I show you longer pay for 10 hours’ service $132 a week is not out how you ca get paid big for while an ordinary mechanic fiddles of reach for Automo- headwork, not handwork; how to around trying to find what is wrong. tive Electricians. Fas- get out of the grease lifting labor, When you consider that 78% of all iprora work. Lng etc., which the ordinary mechanic automobile troubles are electrical heavy Wak is 90°, has to do, troubles you'll realize why the car 5, chit ne or dicaetind . l } : eadwork an owners are combing the market and 10 handwork. Get FREE Book for experts. My free book will Automotive Electricity sive you some surprising facts. is a Profession, not a very g is ¢ la 1 in 1ark- 5 7 : I al Trade. It offers every oy ech ee *] yr book t Ree srg = man the road to quick adie cye-Op S UUOe the il be a No Experience success. revelation to you. | It shows how my late ire ¢ all ‘expert whether Best of all, you can get in this big they come to classes here in Chicago pay profession in 50 days—without knowing about or LEARN IN SPARE TIME AT HOM E. electricity or automobiles beforehand. If you Get it at one It is free. If you act quick you'll also can read and write, you can succeed. We teach be able to take advantage of a most unusual short- you everything in a practical, brass tacks way,° time offer 1 am making. Mail coupon today. which my book explains fully. Cc. J. BUCKWALTER, Pres. oe 2 - Amazing New Way to Train ° 9 y AMBU ENGINEERING INSTITUTE | -° y > ta ad =) 2 > f = ry > 7 ad Whe n the government needed Auto-Electrical Dept. 42 a <0?" ay Experts for the war there was no time to waste. sight oot: ott <o® Men had to be trained 100% right and sent out 2632 Prairie Avenue = 14 * Vyattic We ow ive almost overnight. The man who invented the CHICAGO a BP ERE pyle? oBged . sF Onn 50-day method was the man to whom Uncle Sam Z ae de une act? 9 (ct OR \a\" went for help. Results were amazing. Never before had such a thing been accomplished by any- one. A complete, practical, thorough training in 50 days. So remarkable that after the war, and at a great cost, it was made available to Ambu students only. Ambu has even improved on the original plan by not admitting more than 20 men to a class. No other school does this and the smaller the class the more you learn. When my graduates are grabbed up at big ‘ salaries; when men like Ludlow jump from a $40 a week

How to Get A Position with the U.S. Government Thousands of appointments are made yearly. Good salaries—short hours—liberal vications. Positions open now in Washington and other cities and in Alaska, Porto Rico, Hawaii and the Philippines.

Write to-day for 48-page FREE BOOKLET on CIVIL SERVICE, which tells you how you can get a good-paying position with the United States Government. INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7676-C, Scranton, Penna.

| 597 Inter-Southern Bidg.

Perfect hearing is now being re- stored in every condition of deaf- ness or defective hearing from causes such as Catarrhal Deaf- ness, Relaxed or Sunken Drums, Thickened Drums, Roaring and x Hissing Sounds, Perforated * Wholly or Partially Destroyed \ Drums,Discharge from Ears, etc. Wilson Common-Sense Ear Drums “*Little Wireless Phones for the Ears’’ require no medicine but effectively replace what is lacking o1 defectiveinthenatural eardrums. They are simple devices, which the wearer easily fits into the ears where they are invisible. Soft, safe and comfortable. Write today for our 168 page FREE book on DEAF- NESS, giving you full particulars and testimonials, WILSON EAR _DRUM CO., Incorporated Louisville, Ky.

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118 HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY oto “Built First to Last“ Build your Radio Set Compact for EFFICIENCY ECONOMY PORTABILITY NOTE the small sizes of these remarkably efficient and far famed radio parts. Picture the individuality of a Coto Compact set. Insist that your dealer sup- ply you. If he fails you, write us at once. New Coto Compact Moulded Variometer Size only 314 x 134 x3%4in. In moulded bakelite. Stator is hon- eycomb wound. Pigtail connec- tion to rotor. Range 200 to 600 meters. Base or panel mount. $5 Type 8000.. New Coto Compact Variocoupler Companion piece of the Variom- eter. Size only 3'4 x3 x3%*4 in. Range 200 to 600 meters. Base or panel mount. Pigtail connection to rotor. Type $5 = 9000 .. Trine 9.90 New Coto Compact Air Condenser with Vernier Only 2 7/8 inches square. Rotor Plates soldered to shaft. Stator plates soldered to supports. .0005 c 001 $6 Mfd. Mfd. Other Coto specialties are Coto- gtip Tube Sockets, Honeycomb Wound Coils, Tapped Radio Fre- quency Transformers, Audio Fre- quency Transformers. Typ $5 Type $2.50 4,000 COTO-COIL CO. 87 Willard Ave., Providence, R. I. Branch Offices: Los Angeles, 329 Union League Bldg. Minneapolis ,Geo.F. Darling, 705PlymouthBldg. Atlanta, C. P. Atkinson, Atlanta Trust Co. Bldg. In | for oiling a piece of machinery. | throw out the old oil, rinse the can with | kerosene, and refill with fresh oil. Golden Rule Insures Success (Continued from page 117) or steel, always remember to use a slow speed and a heavy feed. Water makes an ideal lubricant for cast iron scale, while kerosene is used on steel castings. When trying to tap a drilled hole in a cramped place, it is often necessary to use a single-end wrench. This invariably causes trouble, as the one-sided pull makes it hard to tap straight and the tap is apt to break. To overcome these diffi- culties, pull the wrench with one hand and brace the tap with the other hand in a reverse direction to the pull of the wrench. A slightly rounded chisel edge (for metal) will not break as quickly as if straight across. The straight-ground chisel, if not held squarely, will receive the full force of the blow at one spot, while the rounded point will center itself. Never use oil out of an old tramp oilcan Rather Keep all of your tools clean and well | oiled to prevent rust and deterioration. | It is always a pleasure to reach for and | use well kept and perfectly conditioned tools.—JoE V. RomIG. Tilting Porcelain Top Doubles Size of Kitchen Table N Y KITCHEN table can be extended 4 when necessary to seat six or eight persons, and yet ordinarily it takes up no more room and is just as convenient as any other kitchen table. The extension is an extra porcelain top, | obtainable in any ordinary size at depart- The table with the ex- tension _por- celain top down (at right), and with the top raised and supported by legs that slide out from un- der the table proper (below) ment stores. It is fastened to the back of the table with two loose pin hinges and can be removed entirely by taking out the pins. When in a raised position, this top is supported, as shown, by extra legs and side rails that slide out from under- neath the table proper. — GEORGE DRASCHE, Long Island City, N. Y. REMODELING old furniture is a profitable pastime. Captain E. A. McCann will tell what he has accomplished in an in- teresting article next month. Squab Book FREE Squabs selling at highest prices ever known. Greatest market for 20 years. Make money breeding them. Raised in one month. We ship everywhere our famous breeding stock and supplies. Established 23 years. Write now for big illustrated free book, How to Make Money Breeding Squabs, PLYMOUTH ROCK SQUAB CO. 616 HSt., Melrose Highlands, Mass. GROW TALLER! ") §§ INCREASE YOUR HEIGHT Develop your Physical Beauty. Natural, simple Method. Will increase your height and improve your appearance. Write for Free Booklet. Dept. F. THE NATURAL METHOD BUREAU, Atlantic City, N. J. No Joke To Be Deaf I make myself hear after being deaf for 25 years with my Artificial Ear Drums. I wear them day and night. They are per- fectly comfortable. No one sees them. They stop heaa noises. Write me and I will tell you a true story, how I became deaf and me - howl make you hear. Address. Geo.P.Way é Artificial Ear Drum Co., inc. 86 McKerchey Bidg. 1 Woodward, Detroit, Mich. Get More Eggs— Save Feed How to cull poor layers—simple, easy-to-apply methods, outlined in new Free Book,“Dollars and Sense in the Poultry Business,” insures bi egg yie id and saves feed. aoe illustrated. written by ‘TE. > Quisen thori ore- Ee. AMERICAN POULTRY SCHOOL. Dept. 1822 Kansas City, Mo. a= Start Little Mail MeNigge §60Order Business Oty 4-) Home employment evenings. FREE BOOK Beginner’s Outfit furnished. Also tell you easy way to get Agents to sell your novelties. Book sent free. Pier, 553 Cortland St., New York ARTISTS EARN BIG MONEY =e Turn your talent into money. We can teach WZ you drawing in your home during spare time. s'? Well-trained artists earn from $40 to $200 a week. Thousands of publishers and advertisers need the work of good artists. The MODERN METHOD is an easy way to learn to draw original pictures. Write today for full particulars showing opportunities for you. State your age. MODERN INSTITUTE OF ART Dept. 42 7 East 42nd Street, New York City Wrestling Book FREE Learn to bé an expert wrestler. Know scientific wrestling, self-detense, and jui-jiteu. splendid physique, and have perfect ealth. Join is popular school end learn by mail. The famous world’s champions—the marvelous Frank Gotch and Farnier Burns easily and quickly learned at home by mail. Men ESTLING [earn ail the selence 4 and ‘ricke, ey s jam A FOR HEALTH big men with ease. Accept this wonderful offer NOW. Send for tree book today, stating your age. tarmer Burns School of Wrestling, 1782 Ramge Bldg., Omaha, Neb. Save 35 to 60% on all standard makes— Underwood, Royal, Rem- ington, etc. ihe machine thoroughly rebuilt and GUARANTEED. Try five mg at our expense before you uy. WRITE at once for Free Descriptive Circular and Spe- § cial Low Prices. i ane Wynn Typewriter Exchange 22,2075 "Hs: * Become More Efficient through coursesin Mathematics, History, English, Chemistry, Psychology, Education, Busi- ese and 35 other subjects which the University ives by mail, They command credit toward a achelor degree and may be begun at any time. The Aniversity of Chicago 25 Ellis Hall Ti. HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Earn writin, for pu terial teache sells Spare mark: Ame Office

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ed the is an today State al Wn BAC K—* j\ WA \ BACK OF DOOR | WELZ a | yi Z ZA \\\\\ \ 7 | J The Home Workshop chemical cabinet and method of making the joints and door

pieces 114 in. apart, beginning about 6 in. from the bottom and ending 4 in. from the top. Round the edges, as shown, to a per- fect quarter round, after the parts have been nailed and glued together. Bead or round the edges of the back and, after squaring the case, nail on the back. The door frame may be doweled or nailed together with 3-in. finishing nails. The edges of the back of the door are rounded and the back is fastened in place

with brads after the door frame has been squared. A panel molding improves the appearance of the door, but is not essen- tial. Two plain boxes with fronts 4 by 6 in. and two with fronts 5 by 6 in., all not more than 514 in. deep, may be made to form small bins for the bottom compart- ment. The cabinet may be hung with the long edges horizontal, if preferred, pro- vided chains are used to hold the door when open; the back of the door then serves as a sort of worktable. Beside the material indicated in the illustration, a dozen shelf pins, a lock, a | knob, and hinges are required.

Spiral Tsatie: Screw Driver No. 61 an Achievement It has stood up under every test.

119 new/ | Pe ener

OR two years we've been perfecting a smooth-working, sturdy and handsome _ Spiral

Ratchet Screw Driver. No. 61 will meet all your screw driver require- ments and do it ina bet- ter way. The last word in screw drivers—ask to see it in your own / hardware dealer’s. i Works three ways; locks tight in position; spiral action for driving or withdrawing screws 3 right or left hand ratchet action, extended or closed; rigid screw driver, extended or closed. Mark- ings on sleeve indicate each action. Specifications: steel, accurately machined; Spiral nuts,manganese bronze; Ratchet Pawls, tool steel, hardened; Handle, stained hard- wood: Blades (3), special steel,each blade individually tested; Locking device, absolutely rigid in action; Length, ex- tended, bit inserted — 20'4 inches. Spiral or rod, All exposed parts high!y polished and nicke! plated. MILLERS FALI.S COMPANY Millers Falls, Mass. 28 Warren St., New York 9 So. Clinton St., Chicago Manufacturers of Mechanics’ Tools, Hack Saws & AutomobileTools MILLERS FALLS TOOLS 121

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Kind words from a smoker in far Australia A more modest manufacturer might not print this letter. Nevertheless rhe ‘ siastic N theless, when an_ enthusiastic pipe-smoker thousands of miles away takes his pen in hand to say something nice about Edgeworth, a _ breach of modesty on the manufacturer’s part should be forgiven. “Chetwynd,” Copeland Road, Beecroft, New South Wales, Australia Larus & Brother Co., Richmond, Virginia, U. Gentlemen: >. A. Perhaps you are somewhat surprised to receive this letter from Australia, often re- —— to in E ngland, our Mother Country, **‘Down Under. y have noticed in some of your American magazines that I subscribe to, testimony in praise of your splendid tobacco. It has occurred to me that, as one of the many smokers of the Edgeworth in this South- ern Continent of Aus- tralia, I can also add my testimony and apprecia- tion of your world-wide- known and excellent to- bacco. [t must be over twenty years since I first tried your ‘Edgeworth Extra Higl Grade Pi a¢g Slice ; My tobacco nist, one of the leading tobacco nists of Sydney, had a trial con signment of the Edgeworth to test the taste ot his customers. Just at time I was smok- ing several kinds of high-grade im but somehow I could that porte 1 tobac cos not get any of ig that exactly pleased my taste. Some brands were excellent for a while, and then deteriorated. But from the first purchase of your Edgeworth I have found it absolutely of the one uniform standard, aa any change during the whole twenty-odd years | have been smoking it. I have been so satisfied with it that I have never purchased any other make. I have induced a great number of my friends and fellow officers to try Edgeworth, and most of them have the same high ion of it that I have My wish is that your per and continue nowned Edgewort! nin opu company may pros- manufacture the re and that I and fellow smokers of this “Fair Australia’? may be spared to a good, ripe old ‘age to enjoy your fragrant weed Yours sincerely, (Signed) Thos. Skellett For free samples of Edgeworth—gener- ous helpings of both Edgeworth Plug Slice and Ready-Rubbed—send a post- ecard with your name and address to Larus & Brother Company, 59 South 21st Street, Richmond, Va If you will also include the name and address of your regular ‘‘tobacconist,”’ your courtesy will be appreciated. To Retail Tobacco Merchants: jobber cannot supply you with Edge- worth, Larus & Brother Company will gladly send you prepaid by parcel post a one- or two-dozen carton of any size of Edgeworth Plug Slice or Ready-Rubbed for the same price you would pay the jobber. If your Giant Noise- kine Rattle Can Be Heard a Mile OR any festive occasions when the average boy deems a large amount of noise absolutely necessary, this giant noise-maker will be found infinitely safer than revolvers, toy cannons, and other dangerous explosive devices. It can aa ] HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY CLAPPER The rattle assembled and disassembled, and details showing how the five wooden parts are shaped be heard easily a mile away, yet any boy can make it with the simplest tools. Oak is perhaps the best wood to use for durability and loudness. The shape and sizes of the five parts are made clear in the illustrations—JOHN H. SCHALEK, Pittsburgh, Pa. Getting Rid of Old Glue N REGLUING joints that have been previously glued, a good job cannot be done unless the old, hardened glue is re- moved entirely. In many cases it is ex- tremely difficult to scrape off the glue. For instance, a piece often is split so that the surface presents an intricate series of ridges and hollows, which must fit to- gether accurately. To clean off the glue on such a joint use a stiff brush nail-brush will do—and hot water. This will do the work effectively and leave the surface in the best possible condition for re-joining. Allow the wood to become thoroughly dry before making new joint. DO YOU LIKE TO DRAW? CARTOONISTS TRAINED BY W. L. EVANS MAKE MONEY Some of the cleverest cartoonists are former students. They had no experience bef: enrolling, but worked at the lessons during their spare time and found CaArRTOONIs) Evans’ MetHop “easy to learn’”’ and are now making good money. It is not hard to learn to draw originals when shown in a practical way. The School is recommended by well known cartoonists because they know the students are handled right. If you like to draw and want to be able to sell your drawings, send a sample of your work (either a copy or an original) and let us see what youcando. We will send you the port- folio of cartoons and full details about the school. The Course is NOT EXPENSIVE THE W. L. EVANS SCHOOL OF CARTOONING 825 Leader Bldg., CLEVELAND, OHIO Reduce Your Waist in 10 Seconds You can pukuaite do it now with the ‘Won- der’ Health Belt. It will take only the time required for adjusting the belt around your waist to accomplish this reduction and to bring relief from the strain of excess weight, which your abdominal muscles are carrying. You will be agreeably surprised at the im- mediate relief from bodily fatigue and dis- BEFORE AFTER You will know the satisfaction of comfort. having a well poised figure. And, best of all, fat begins, at once, to depart. Then good healt! muscular tissue replaces it. In a month or so, y can take from 4 to 6 inches off your waist. THE ‘“‘WONDER”’ HEALTH BELT will do these things. It is scientifically constructed from strong, light-weight fabric. Easily adjusted and easily washed. TRY IT AT OURIRISK We will send this Wonder Health Belt for 5 da trial at our risk. Send your name, address and present waist measure. If no tape is handy cut a piece of string to the proper size and mail it to u When postman delivers belt, deposit only $1.00 with him. If 5 days’ using proves it helps you, send balance of $2.00 in full payment, otherwise return and get your dollar back without question. Send today. WEIL HEALTH BELT COMPANY, INC. 102 Hill Street, New Haven, Conn. BURN w.ceGAS tngous 2! COAL STOVES Change yourcoalor woodstove .“"y, AGENTS into a gas stove in 3 minutes, ;? 4 WANTED A Child can doit. Burn kero- sene Vapor Gas— hotter than coal or wood and costs less. Safe and simple. FREE TRIAL Just turn a valve and get even heat instantly. No ashes, no dirt, no smoke, no wood to chop or carry, No fires to build and feed. No fuel wasted. Cooks and bakes better. No damage to stoves. Makes its own gas from common coal oil, cheapest, cleanest fuel. Guaranteed five years. Money back i again if not satisfied after 10 days’ trial. Write for FREE folder with proof and SPECIAL OFFER. SIMPLEX UTILITIES MFG. CO. 215 Simplex Bidg. 1428 No. Wells St., Chicag®

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HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 121

Toy Coaster Wagon Is Motorized for Nine Dollars INE dollars was all it cost to turn a toy coaster wagon into the “auto- mobile” illustrated. The gasoline engine,

which had once driven a washing machine, was bought at a second-hand store for five dollars; the coil, from an old Ford, cost only a trifle, and the battery, at three dollars, was one of the heaviest expendi- tures. The engine is attached to the bottom of the bed near the rear end of the coaster. nown its are = \t Coyne ‘work } us see op a | E $65 to $200 E SHOOL A Week, Or Go In Business : For Yourself And Make 2 A gasoline engine from an old washing machine 3500 to 15 000 iD, OHIO propels the coaster smoothly on paved roads 9 a a Without one gree A of advance payment let us A Year plz in your hands to s to examine, t - spect, _to stuns, to approve, . re og Be aster It drives one of the rear wheels by means = = wae St Be Gon Shed piece in watch creation. A watch guarantee > 9 7 7 to last a lifetime, which passes the most rigid of cog wheels and a chain taken from an Pe hah ay pnerment ~ = eben ger ‘the Greet Hente = ym Swed old bicycle. The whole world of electricity is open to the pres System, and other great American trunk lines. The handlebars and post of the same — pon = thes oe plhonndn dig, Reape oe pe Page 12 of our Watch Book broken-down bicycle serve as the steering * re the greatest outlay of elec: is of Special Interest to You gear, the prongs at the bottom of the a everything from door belis to power plants. Act tat anise. lane: waoke: ioe = 2] ré ras av “ aay fac & ee Gane a ace cc machine runs well on sidewalks and paved ting, mater’ tastahetions, eutgnastie wort’ waa money down—a wonderful offer. streets.—B. F. CLARK, Hutchinson, Kan. hundreds of electrical jobs. That's why we can SANTA FE WATCH COMPANY train you to become a Master Electrical Expert. 280 Thomas Bldg. Topeka, Kansas 21 ; ~ — — Home of the Great Santa Fe Railway) One Man Raises Old Fence Posts No Books No Lessons No Classes , ———_— = ee ee ee ee ee eee eee e of again Santa Fo Watch Cor with Powerful Puller You Do Actual Work i e 280 Thomas Bldg., Topeka, Kan. k realt! : : ra ‘ } wy ae , The Coyne practical course includes no books, 1 80, You gee ae Warne See Seen see _oenenn 1. Tippecsnee County, printed leongus or uscleas theury. We train Jot ON Mansy Dawn "Gtas on the Santa Fo Ind., uses the homemade puller illus- to work with your head and hands on the same BELT Special Watch 7 r kind of electrical apparatus as you will find ‘‘out : : 8. trated for raising posts. The discarded inthe field”. Age, lack of experience or educa- nstructed z . X tion is no drawback. Our students range from adjusted wooden tongue is mounted on two old 16 to 60 years of age. Coyne gives yeu Sree & Life ~ . oe * ae ‘ - ¢ hai Scholarship which enables you to stay as long as binder truck wheels and a hook and chain you want without extra charge or return later for r 5 days more practice, and assists youtoa sition after ‘nan and : oe Ml Ee oe graduation. We also include Free a jo course, — | eo | Earn while you learn! We help students nly $1.00 | to secure jobs to earn a good part of their you, send | living expense while studying. ise return | mn. Send 1 e vic, || Something New! /” / Send for Free Book onn. I py the a Renenes 10 Send the coupon today for the Big Free Book Bre Knit we ‘dngic Dn ss a Da which shows the Great School of Coyne and a ia “eit Ser cy cra ad 6 iy reat part of our massive electrical equipment. a onde enna! l Here’s proof that When you read the enthusiastic letters of Coyne , wither . 7 sr age s we have a oe graduates, you will be convinced that the only making potas EL LONGCORE, zs place to get a practical training is in the q Lanta tic rosea, Shabedie made $14 in five’ faa School of Coyne. for only $1.00 or can be jena K, Nebr., averages usedas a premium with 2 $1.00 per hour every working VE Aare: vs gs day. MRS. MOSER, Pa., says | Electrical $3: 20 fine house. it is easy to make $10 a day } , AGENTS caltiea® with our line. Some good territory | . WANTED j still open, but write quick for terms Endorsed by Electrical Industry i and free Outfit offer. ———— - Cc. H. STUART & CO. . P Long 968 Union Street Newark, New York 1300-1310 W. Harrison St., Dept. 13-62 Chicage, Ill, Mi | Pest ena eeees sees ase eee

SPORTS SODIES for FORD and CHEV. 490 at $34. Sy | Made of odds and ends, this puller saves

the time and labor of digging posts + Coyne Electrical School, Dept. 13-62 itesize @@ , i H 1300-1310 W. Harrison St., Chicago, Ill. Bh abet 8 <b UNDER : Dear Sir: Please send me free your big catalog —You =~ SLUNG are fastened to the lower end so that the Gnd Sell particulars of your special offer. ee tp chain can be fastened around the post. ee laa bode ae 75 By throwing his weight on the other end | : Penn naaesy i eaeseneeesatae idee mon coal oil, piles jae are manufacturers and our quantity production of the pole, the farmer pulls up the post H BERGE pikitintntadtdudnndmebnatinns athe ye eer raables ws bo quote cnceptional bow | rices, Our unique faster and easier than it could be dug out 8 ECIAL OFFER | foija cr ive partieutars on ek “ow vo] | by hand.—J. C. ALLEN, West Lafayette, | § -......--------------------- ------------ ae CENTRRE AUTO SUB N'GO. Dept. 122, Lousvute. xy.) | Ind.

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122 MECHANICS’ HANDBOOK

330 PACES More than 300,000 sold ANDIEST book of its kind ever written. Pre- pared by experts under the direction of the Interna- tional Correspondence Only ¢ Schools. Written in lan- guage that you can undere- stand. Note this partial list of subjects: Weights and Measures; Easily Under- stood Mathematics; Formulae; Mensura- tion; Belting; Hydro-mechanics; Strength of Materials; Boiler Design; Care and In- spection of Boilers; Horsepower of Boil- ers; Chimneys; Exhaust Heating; Machine Design; Horsepower of Engines; Boilers and Pumps; The Slide Valve; Belt Pul- leys; Rope Belting; Cylinders and Steam Chests; Electricity; Currents; Wiring; Dynamos and Meters; Batteries; Cable Testing; Compass Surveying; Curves; Leveling; Etc. Just mail this advertisement with dollar bill and your name and address, and this 330-page I. C. S. Mechanics’ Handbook or any of the other I. C. S. Handbooks that you want will come to you by return mail. — ee ee ee INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7675-C, I enclose $ . for which send me, the Handbooks marked X, at understood that if I _am_ not entirely satisfied I may return any or all of them within five days and get my money back. 0 MECHANICS’ HANDBOOK Oo Automobile Handbook O)Radio Handbook ) - lectrical Handbook LjSalesman’s Handbook {JChemistry Handbook L]Advertising Handbook (JBuilding Trades HandbookL/Bookkeeper’s Handbook Scranten, Penna, postpaid, $1.00 each. It is Natne Address

LOOK FOR THE RED RING ON THE LUDEN -YELLOW BOX MENTHOL COUGH OROPS GIVE QUICK RELIEF $25.00 in Prizes See top of page 6 in front of book for details

Sewing Cabinets Built at Home (Continued from page 81) indicated. The posts are 13% by 13% by 2514 in., plowed to take the plyw ood pron panels, which are 4 by 10% By 18 in., and the back panel, which is 4 by 12% by 18 in. The top drawer hie # is 34 4 by 314 by 1134 in.; the center drawer felted 34 by 2 by 11 34 in., and the bin front 34 by 10 by 1134 in. "The drop leaf is ae ported by an ornamental iron bracket or a hinged wooden bracket. In finishing either cabinet, the wood | should be stained, filled, and given several coats of thin white or orange shellac, each rubbed with pumice-stone and crude or raw linseed oil. Several coats of good fur- niture wax can then be applied, if desired. For a varnished finish, stain and fill the wood and give one coat of white shellac and two or three coats of varnish, rubbing the last coat with pumice-stone and oil. Both the cabinets were designed by George F. Kaercher especially for Popu- LAR SCIENCE MONTHLY. The complete working details and bills of materials are contained on a single large blueprint Mo. 31), which can be obtained by sending 25 ce nts to the Blueprint Service Depart- ment, POPULAR SCIENCE MONTHLY, 225 West 39th St., New York.

How to Cover a Ceiling with Wallboard Single-Handed NY one who has attempted to cover a ceiling with wallboard, especially with large sheets of heavy gypsum board, knows how difficult it is, even with a or two. I have overcome the usual difficulties, however, by the simple expedient illus- trated. Take two boards about 6 in. wide and as long as the room is wide. Hinge one end of each board to the plate or studding, spacing the boards apart about one third the length of a sheet of wall- board, and below the ceiling, the thickness helper

: ae =f ss 7 A i r J > —= — " le.) | |= ae: ena 08 iT PVH IC | RIC CIAIE \| j\ \ { L - | Ne I ee a= iN Scr == i

qt Wry wh a, = } F } x if ~ ; ome +) | bo% / Rid ie | ii 1 / Biwi 1 WI The sheets of wallboard are hoisted to the ceiling on two long, hinged boards of the wallboard. Nail a cleat on each board about 3 ft. from the free end. A rope is tied around the free end of each board about 2 ft. from the end of the board and passed over pulleys attached to the joists or rafters above. The wallboard sheets are then placed | on the two boards and drawn up to the | ceiling. The loose ends of the rope are tied to spikes driven in the studs. It is then comparatively easy to shift the wall- board sheets into position and nail them. A piece of flooring as long as the room is high, with a short piece nailed on the end in the form of a T, is a help in shifting the M. VANSLYKE, Jacksonville, Fla.

sheets. seas

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY ——

Earl Roberts, tenor-banjo artist with the famous Westphal \\ Orchestra, Columbia recordart- \\ ists, uses and endorses the New Gibson Mastertone Banjo. You, Too, Will Appreciate the New Gibson Mastertone The same qualities of this tenor-banjo which have captured artists in the great recording orchestras will win you, whether you take up the banjo for pleasure alone, or for the wonderful opportunities for profit which it affords. No instrument is more popular today than the banjo. Only in the Gibson Mastertone can you obtain the Gibson Rim and Ball Bearing Tone Tube Constructi The Gibson Tone Projector and the other exclusive ( son construction features which make it easier to play, marvelous in tone quality and carrying power, anc absolutely dependable. FREE BOOK. Send for your copy and details of Easy Payment Plan on any Gibson instrument, including Tenor-Banjo, Mandolin-Banjo, Guitar-Banjo, Cello- Banjo, Mandolin, Mandola, Mando-Cello, Guitar, Harp-Guitar and Mando-Bass. Mention instrument when writing. 205 GIBSON MANDOLIN-GUITAR CO. Parsons Street <alamazooe Michigan

Pewre,teach ART Meyer Both ¢ ompany, the largest Commercial es Organization in the World offers you an unusual opportunity for practical training, based upon twenty-three years of success. This nationally known organization each year produces and sells to advertisers over 15,000 commercial drawings. Meyer Both in- struction is the difference between successful fact and experimental theory This well paid profession eq\ ally open to men and women. Home study instruction. Get Facts Before You Enroll in Any School Ask the Advertising Nianager of the leading news- papers in your city, anywhere in the United States, Canada, England or Australia about the Meyer Both Company—let them tell you about us. Write for our illustrated book telling about the success of our students—for one-half the cost of mailing—four cents in stamps. MEYER BOTH COMPANY Department of Art Instruction Michigan Ave. at 20th St., Dept. 35, CHICAGO, ILL. Note—To Art and Engraving Firms: Secure practi- cal artists among our graduates. Write us. MAKE INTO vane FORD tiie SPORT CAR Other types down to $3.50. Famous sure fit, life- size patterns and picture instructions show any, can easily convert your Ford into this fast, saucy Sport Car as hundreds have done with @ few S th of material from the

ONLY ip0

, | Keen, Clasey ~ .4 Up-to-the-Minute rides wonderfully easy. Order NOW while we can make 9006 delivery. Send 5c coin for ere ne orearene of Sport Bodiet, *Jifdy’’ Tops an *Gosum KUEMPEL CO., 526 ~-seliletec+ Bidg., Guttenberg, lowa

th

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A te the mnie hich have estras will r pleasure for profit the banjo. ybtain the mstruction, usive Gib- ier to play, ower, and ‘ils of Easy including jo, Cello- >, Guitar, nstrument CoO, Michigan argesi yn in the rtunity for three years rganization tisers over Both _in- cessful fact ssion equally on. ny School leading news- in the United ustralia about let them tell terial from the vare store. No need to lay uP the car. The *PAL’’ with ‘conical des wheel pa ns, Pre sted tal ’Streamiine ir only $6.40) de- red. Built low can make #00 f Sport Bodies, enberg, lowa SO HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Improving a Porcelain ntaine | Used for an Aerial Lead-In HE porce- lain tube ordinarily used as a bushing for insulating the radio lead - in where it enters through a win- dowsash,frame, or window board, can be improved BOLT AND NUT TUBE / / SASH/ /RUBBER | / PORCELAIN | IRON WASHERS The airtight bushing greatly by running a threaded copper rod or ordinary bolt through it, as shown. Rubber and iron washers at each end make the tube practically airtight and no cold air or rain can come in around the | wire. —IRWIN E. WALTON, Bantry, N. D. Spring Suspension Protects Vacuum Tubes from Jars | oe mounting radio vacuum tubes flexibly, the most practical scheme I | have found is that illustrated. Four brass | springs are wound from spring wire, ob- tainable at hardware stores for about 10 cents a spool. COILED The springs serve as connecting, wires shock The ends of the springs are soldered to the four terminals of the socket, and in this way they provide connections and absorb- ers at the same time. This method of tube insur- ance is well worth the trouble, especially in portable sets. It should be remembered, too, that a vacuum tube, after being used to some extent, should not be placed in a portable set without first protecting it in some such way, since the filament becomes brittle. —CARTER FISKE, New York. Thawing Frozen Auto Radiator with Engine Heat FROZEN 44 radiator often can be thawed out in an emergency by reversing the fan and blowing the hot air sur- |rounding the engine through the radiator framework. Loosen the nut that holds the fan arm in po- COVERED RADIATOR sition and lower this arm sufficiently to allow the belt to be crossed. Then raise the arm until the belt is tight on its pul- leys and fasten it in place. When the en- gine is running, the hot air will be blown against the radiator cells and any will soon be melted. ice THE soldering iron is a useful home tool. In next month’s Home Workshop, Henry 5. Laraby tells how to solder and Dr. E. — | | Bade discusses solders and fluxes. 123 | Sears, Roebuck ana. ‘The Worlds Biggest Mail Order House 3,000 OHMS Head Set Atlast—the inexpensive, efficient head set you've been looking for, and only $2.98! Makes clear those distant signals. Fits your head as comfortably as your cap. Com- plete with six feet. of good grade cord. Excellent workmanship. Order NOW! Shipping weight, 14 Ibs. Shipped from CHICAGOor PHIL- ADELPHIA store. $ 57AB9220—. ... fee | der Direct From This Advertisement Save On All Radio Supplies Our big FREE Book shows hundreds of bargains in radio supplies and complete sets. Highest quality apparatus. Satis- faction guaranteed. This new, ar woe 3 cist of tells “‘How to Build an Aerial.” Complete list broadcasting stations. Many new ‘‘Hookups Write today! Ask for Radio Catalog No. 91P98. Mail This Coupon NOW Bn See RE | | RS Sears, Roebuck and Co. hicago — #£Philadelphia Send me FREE Radio Catalog No.91P98 ooo ocean - i eee : sousnsonaiainee State Box No.... OMNIA WONTON sco cc se cocsecancethcteeooace AE OSE een ene $25.00 in PRIZE See top of page 6 of this issue for full details. T IS HERE! The most wonderful heating appliance of the age. Burns a low test oil for fuel. Cheaper than coal. Eliminates dirt, soot, ashes, and work required in coal burning furnaces and boilers. Can be installed in any type of furnace now in the home. We Want a Representative In This City to supervise the demonstration, sales and in- stallations of HART OIL BURNERS. No experience necessary. We teach you. Very little capital required. An established dealer preferred. Every Hart Oil Burner backed by manufacturers guarantee. 34 years in business. Wonderful money-making opportunity. Write Immediately For Full Particulars HART O1L BuRNER Co ee PEORIA — ILLINOIS =

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124 HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY A RAILWAY. a EARN UP TO 750

Cardboard Carton Forms Simplest Toy Stage By H. S. Trecartin T DIFFERENT times I have made

Expenses Paid two ‘‘picture theaters,’’ as the chil- =e ete Per Month dren call them. These seem to give them » a more lasting pleasure than do most of their 1020 Gmpiere Many toys. Children love to cut out the color- ea ea ae T ful and often really beautiful pictures from Lo wd Sp eake? ee ; Chances magazine covers and advertisements, and

e e ques “sé e at fr for for such prints this ‘‘theater’’ furnishes an Enthusiastic to t! attractive setting. how Advance- , —is the only word that deseri ot Most of the materials can be had for the ‘ only word that describes pe ates sacl iain “anaemia sige ht those radio critics who have chosen Vv ; wil ng, Gnd wasever = 0 be bougn Morrison Loud Speaker. For them U | In This will not cost more than 30 or 40 cents. Radio has taken on new delights. 31 { © ° ’ ° ° 3 1, jy lhe whole job can be done in an hour’s 3right stars of the musical comedy _— / Uncrowded time with a knife and a screwdriver. stage, famous lecturers and singers aud s The stage is made of a strawboard car- all are theirs no matter where they 23 Profession ton or packing box. The flaps on one side live—every night as long as they mis ~ | are turned in at an angle to form the care to stay awake. — Stanley W. Dress writes: “I have worked Real it pre ran without annoying vibra- 2: as a Traffic Inspector for some time and a , tions as soft or loud as you please—that de- aS a Prafhic I ispecto bg bao oy ‘ ; UPPER FLAP ~~, 77 WINDOW FRAME scribes Morrison attached to your phonograph wt have found it the most satisfactory and ~ FF. : ae : : ’ : . tone arm or used with a horn. pleasant work that I have ever been en- ¥ x meee: : 37 gaged in. The hours are short. In some / T\\ CURTAIN | $] 00 27 placés I work only five and six hours while ' NW? ff , Win ROO — ‘ Bi in others I work eight hours. I have never 4 \ Gy y ‘ That’s all Morrison costs re worked over eight hours. ' NY / CURTAIN, | complete with 5 foot cord exat ; fw a ba? _ Nickel Plated Model ee — A S Many Opportunities To Travel my This perfect little loud speaker has no rivals. : ‘This work has satisfied one of the anfbi- Mi k& \' co you your money back if you don’t tions of my life and that is traveling. There om’ or cations ae ’ : is no other work that gives more oppor- A220 Ask for descriptive 2 color catalogue. 9% tunities to travel than that of a Arey i) DEAI aan t: Traffic Inspector and at the \\\\ | | TI — fio f. a pect ‘ » to rec in x f on ae ASR HH housands Of new radio fans have receivir — is interesting and in a -- BULBS ~~ Py I ] Hi sets—Christmas presents. “So one needs v CcUlve es i “| ees mammal | NI a Morrison Loud Speaker. We will show you DEO! I can recommend the course “WINGS -= = A Ill how to merchandise Morrison. Ask | us for thin to anyone seeking a position that geese « our plan at once. is tl pleasant and profitable and to ~—" ae er rect ts proc wd BOTTOM FLAP--’ ‘PLAN MORRISON LABORATORIES, INC. ing ‘fe h _— is no — of he 341 Jefferson Ave. East - DETROIT, MICH the ha or the eng si “6 me - Children enjoy displaying colored pictures cut phon to it equires so Httle cr ones eltorts from magazines in this easily made theater = = cost and no one need tay at home to study it. | The Course can be studied during spare | " time and any person witn a common school 7 = p mi . so - A M t Effi t 7 | education pe easily make a success of it.” . Pp “rigs a — Fak " the = side Is | a0S icien 00 P, ; P eR ; es } cu : oT 2 a piece Ol Window ¢g ass. HOME WORKSHOP POSITIONS GUARANTEED | Electric lamps, placed behind the The MON- mi. | wings, are hidden from the audience, but ARCH Jr. - . | . MAIL COUPON== === === | ~ eth preg Re ee er ae WwW. B. & J. E. BOICE ; a STANDARD BUSINESS TRAINING INSTITUTE ie stage may be decorated Dy pasting | pepe. P.S.2, 1730 Norwood Ave., Toledo, Ohio BUFFALO, N. Y. colored paper or wallpaper over it, or by ) Send me, entirely free, Booklet No. D-64, giving | painting it with oi] or water colors. A ; full parti lars about course in Railway Trafhe In- | cloth curtain should be provided; it may ; ‘aia | roll up on a rod or, better, be pulled each ‘A a way from the center by two strings, car- No ried around to the back. Ma = ‘ AC TL ick eenEe bi seh ue esanusk ones ee Two cheap porcelain lamp sockets are ee ] 2 Ox (Continued on page 125

ee |

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ibes sen lem hts. edy Pers hey hey ibra- + de- raph vals. lon’t iving 1eeds you S for NC. MICH rool small nventors, mpletely ni-quick ns. t. Bed— 2S > Mace ler price, L CO. y, Ohio ofit shines ines six ma- ‘rand buffer. ing, dadoing HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY The Opinion of To find out what influences ambitious men and women to enroll with the American School, an advertising agency sent outa questionnaire to one thousand names, taken at randomfrom ourstudent rolls. The answers to three of these questions show very clearly how our School is regarded by our students, both before and after enrolling. Why Students Inquired About ur Courses 31.5% wrote only to the American School, be- cause our advertisements impressed them more favorably than the advertisements of other home study school 27.0% had heard of the American School before. 23. 7%, answered several home study school ad- vertisements, so they could select the best. 15.1% were recommended to our school by a friend or acquaintance who had taken one of our courses. 2.7% inquired for various other reasons. Why Students Considered Taking a Course With Us 37.4% wanted to qualify for better positions. 22.5% wanted assistance in their present work. 20.7% wanted more information on the subject for which they enrolled. 11.2% wanted to prepare for college entrance examinations. 7.4% wanted to “brush up” on subjects previ- ously studied. .8% enrolled for various other purposes. Whos, Students Really Think ut Our Courses 97.2% say our courses are “Good.” 1. 4% say our courses are only ‘“‘Fair."’ 1.4% ,,8ay Our courses are “Not what they ex- pected.” When you take the average opinion of 1,000 people, selected at random, about some one thing, oe will get a definite idea as to the worth of the thing. The average opinion of these 1,000 people is that our courses are O. K. Do you need further proof? If you want to get ahead and are consider- ing a course of practical training, you will find that the American School is the best place to get that tre 1ining. From us you will get the best grade of training at the lowest cost. And further— Our Money-Back Guarantee Protects You You cannot lose when you enroll with us. If after you have finished your course -~ ~~~ you are not absolute- iy satisfied, if you do not believe that the training we gave you will help you to get ahead, just write us and we will refund to you every cent you American School The American School is not a money-making cor- poration, but like resident schools and colleges, is chartered strictly as an paid us. Mark the J ‘‘Educational Institution, coupon. Your re- not for profit.’ quest for information More than 200 famous puts you under no engineers and educators prepared the special in- struction papers for our students. For overa quarter of a century, Big Engineers, Educators and Business Men have recommended the American School. They know that = long experi- ence as an educational in- D Dept. G-275 stitution guarantees better rexel Ave. and training at less cost than 58th St. can be given by any school Chicago Sok conducted for profit. » U.S. A, obligz 4. and no AGENTS WILL BOTHER YOU. American School COURSES TAUGHT American Schoo Dept. G 275, “tery Ave.& 58th St., Chicago. Gentlemen: Please send me full information on the subj ject checked. It is understood that this request places me under no obligation and that no agents will bother me. -Architect |B 1ilding Contractor or Carpenter \utomobile Engineer \utomobile Repairman -- Civil Engineer \dvertising Manager Business Manager -Financial Manager -Sales Manager -Cert. Pub. Accountant Accountant & Auditor ': Bookkeeper -Draftsman & Designer Electrical Engineer Ge *neral Education .. Personal Analysis .. Lawyer . Machine Shop Practice .Photoplay Writer -Mechanical Engineer -Shop Superintendent -Employment Manager Steam Engineer . Foremanship .Sanitary Engineer .. Surveyor (& Mapping) .. Telephone Engineer .. Telegraph Engineer - High School .. Fire Insurance Expert . .Wireless- Radio . Business Law . -Undecided — a | Cardboard Carton Forms Stage Denial (Continued from page 124) set behind the wings and connected with lamp cord carried through holes punched in the box to a socket switch. A drop cord from any house-lighting socket can be connected with this, if electricity is available. It will be just as easy, how- ever, to connect up small dry-cell lamps and then the batteries also may be placed inside the stage. Radio Soldering Copper Reaches Easily into Tight Corners OW to solder connections in awkward corners is a problem that frequently confronts the radio fan who builds his own sets. It is a great aid in such cases to have a soldering copper made as shown #% COPPER ROD 5° STEEL Because of the heavy body this small solder- ing copper retains its heat for,some time by inserting a copper wire or rod into a steel, iron, or copper body about 34 in. in diameter and from 3 to 5 in. long. A handle of any convenient length is then fitted to this head. The bulky part of the head retains enough heat to keep the point warm for a considerable time.—J. D. Connecting an Extension Cord with Your Radio Phones HE broadcast listener often wishes to share his headset, but finds it incon- venient because of the shortness of the cord between the two receivers. This is overcome without rewiring the phones by using two extensions preferably made of silk-covered wire of flexible tinsel. The original cord is cut about 5 in. from one of the receivers, the cuts not being faa] made exactly opposite each other. To 9 / rama o—— SNAP | / FASTENERS EXTENSION CORD QRIGINAL CORD Diagram showing how the telephone cord is cut and two long extensions are inserted each of the four wire ends thus produced is soldered one part of a large size snap fast- ener. The interlocking parts of the fast- eners are soldered to the ends of two 10-ft. lengths of the new single cord, which can be purchased by the foot. One must be careful not to mix up the connections. Usually a cord with marked insulation runs between the receivers, connecting them in a series, while a plain insulation is used on the cord from each receiver to the terminals. The new cords can be neatly sewed together in places with green silk thread to match the in- sulation.—KarL L. MartTIN, Cleveland, Ohio. GET INTO THE NEWEST PROFESSION— “Laboratory Den- tistry.”’ Biggest op portunity for success of century, because there are ten times as many jobs as men to fill them, because there are a dozen cities crying for Laboratories for each EXPERT capable of operating one! 60,000 DENTISTS NEED LABORATORIES! Only a few hundred Laboratories in all the U.S.—most of the m in Chicago and New York. Dentists can’t afford to do their own mechanical jobs. They can buy the services of a Laboratory Expert at $3.00 an hour and sell their own time at $6 to $15 an hour, and they want better, quicker, service than they can get now! OPEN A LABORATORY of your OWN! Jow Wilk of Chic ago started a couple oft years ago ALONE. Today he employs 60 Experts and his Laboratory is one of the biggest in the U. S. Boos in Minne- apolis is reported to em- ploy 125 men and to clear $40,000 to $50,000 a year. You can start your own Laboratory with as little as $100 investment. EARN While You LEARN! Day students make all or part cost of course by part-time night work Night students can find plenty ol good iobs in Chicago “ to see t hem Learn to make el Rubber Plates, a Bridge Work, Crowns, Metal Base Dentures. Inter- esting Catalog FREE! Catalog ° tells you how quickly and easily you can get ready, how hun- dreds of others haveSUCCEED ED! Tells you how you learn / infew months BY DOING ACTUAL LABORA. ro RR ¥ JOBS under k world's B greatest Mechani cal Dentists! Brings you hen FREE R. R.FARE offer and other big induce a ments. Write for free catalog today! os McCARRIE SCHOOL OF | MECHAN- ¢ AL DENTISTRY ¢ Dept. 302, Sa and 36 W. patel St., Chicago TT TTririee ee??? tet tld Pi McCarrie School of Mechanical Dentistry Dept. 302, 34 and 36 W. Lake St., Chicago Without obligation please send me your FREE R. R Fare Offer and free catalog with complete information about how I may become a Dental Laboratory EXPERI NGG acicaxcnnssawesvoveddines St. No. or R. F. D.

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Y/- Mahoganite Has the beauty of polished mahogany | AHOGANITE RADION Panels have a satin-like finish comparable to that which age and a skilled cabinet maker give to mahogany. MRadion Dials and Knobs can also be had in Mahoganite to match. Insulation PANELS 18 The Supreme Miniature Cedar Chest Sewing Boxes Find Ready Sale HILE con- fined to the house matism, with rheu- I made use of my spare time in building miniature cedar chest sewing boxes from pieces of Ten- nessee cedar left over from large chests. They were made exactly like large chests, but lined with silk and with small pockets in the ends for spools and ribbons and were finished in the natural color with varnish. Being more or less of a novelty and very attractive, they sold at a good price, so that I dispose of all I can make.—EARL ForD, Bangor, Me. —— A cedar sewing box Old Auto Hub Serves as Useful Bench Fixture ORN out and discarded auto parts often can be worked up into ser- viceable tools for the home workshop. A | handy fixture of this kind is illustrated. A rear wheel hub from a smashed wheel is obtained and the side carrying the hub cap is faced off flush with the surface of the flange. This leaves the main part of the hub with a tapered bore, into which 4 BENCH PLATE i ve) PARTLY Pd ' k FACED OFF \iteasreant “LAG SCREWS A rear wheel hub forms swivel mounting for bench V-block, and riveting anvil plate, fits the tapered end of the axle. The hub is screwed to the workbench. Tools such as a bench plate, a V block, a bent riveting anvil and the like, each fitted with a rear axle shank, can be Stock Sizes | placed readily and quickly in the socket | 6x7 7x21 | 6 x 10: 7x 24 6 x 14 7x 48 6 x 21 9x 14 7x9 10 x 12 7 12 x 14 7 12 x 21 14x 18 20 x 24 Look for this stamp onevery cnn ae panion (A) Pa’ substitutes and pato 1 RUBBER CO.NY. imitations, AMERICAN HAR American Hard Rubber Co. 11 Mercer St. New York / and revolved into the most convenient position. As the threaded end of each | tool shank projects through the bore of the | hub, an upward tap with a hammer will knock it out. The castings for the bench plate and the V block are bored for a press fit over the turned end of the axle. Refinishing an Old Table A* I was passing a furniture store re- “ cently, I saw a black drop-leaf table, | with clusters of flowers painted on the leaves. This gave me the idea of removing the dingy finish from an old gateleg table | of my own and painting it with Japan | black, a flat color. I then cut pictures of flowers from a magazine and pasted them HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Sell your snapshots You can make your camera self-supporting by selling your pictures to “Popular Science,” Mr. J. G. Pratt, of Washington, D. C., tells in a recent issue of The Camera, how he has made his camera pay for its upkeep. This is what Mr. Pratt says: “Every red-blood American finds him self at times in some little difficulty which he overcomes by the inventiveness of his own brain. These ideas are worth money, and if you will but take a photograph or make a sketch of the thing in hand and send it to the right publishers, you will not only have the satisfaction of having overcome the difficulty, but more often than not will receive a fair size check for your trouble “For instance, the motormeter on my car insisted on wearing out the fiber washer, so that if screwed down tight, it would point forward instead of crossways. This I cor rected by drilling a small hole in the lower flange, threading it and inserting a set screw It worked fine, and I not only had the satis faction of eliminating an unpleasant imper fection in the car, but a photograph of it brought me a check from Popular Science.” Popular Science Monthly is always ready to buy live photographs at good prices from amateur photographers. These need not necessarily concern the results of your own ingenuity. The shops and factories in your town, the hardware, automobile accessory, radio and department stores are constantly showing new mechanical devices that would | be of interest to Popular Science readers. | Your neighbors are rigging up ingenious | homemade appliances to aid them in paint- ing their houses, operating their cars or radio sets. Good photographs of things of this sort, taken to show the operation of the devices in human hands, are always in de- mand by Popular Science Monthly. So be on the lookout for a chance to make snapshots. Send them to The Camera Editor, and if they can be used we will promptly send you a check. Camera Editor PoPpuULAR SCIENCE MONTHLY 225 West 39th Street New York Be the First to Use Smooth-On No. 1 and Get the Credit for the Saving! MOOTH-ON stops leaks in auto radiators, burst- ed water jackets, gear cases, tanks, heating boilers and radiators, tanks, water, gas and steam pipes, ete., in one simple application. Keeps bolts, nuts, grease cups, hub caps, etc., from loosening and dropping off.— Makes handles tight on tools, kitchenware, door knobs, canes, etc.—Joins iron, bri lead, aluminum, wood, concrete or glass t each other, and holds well in many pla where nothing else can. Needed inevery home, autoand workshop and when used as di rected makes big savin s stops many nuisances. 144-page Repair Book FREE if you mention this magazine and This Book Seven kinds of Smooth-On are on the center of the table and on the | leaves. The table was given three coats of varnish, the last coat being rubbed down with pumice-stone and water. SMOOTH-ON made each for specific purpose Get Smooth On No. 1 in 6- 1-lb. or 5-lb. tin at nearest hard- REPAIR ware store BOOK SMOOTH-ON MFG. CO. Dept. 58 574 Communipaw Avenue Jersey City, N. J. wreath UEC TT TCM Trek he) hUM™ TI SOTA eee AaTeethUCUM ET Um AM FTF AM COSYIMIATSVY | 6CRCASAATOTIV EY 1 th an ar de th: lat ly tul in tin thi Wil the be: ge) esc por enc cul ard thi of the vio duc ade to her sto

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I Ots porting cience,” C., tells v he has >». This him- which of his loney, iph or 1 send t only rcome ot will ible. ly car ner, so point I cor- lower screw. : satis imper- 1 of it lence.”

ys ready ices from need not rour own Ss in your iccessory, onstantly lat would - readers. & ingenious in paint- > cars of things of ion of the ys in de- y- : e to make Camera 1 we will NTHLY Jew York AL = qs

nd steam ication.— ub caps, ng off.— ~henware, ny places > autoand ised as ai vin s and e 0k magazine »0th-On are c purpose J in 6-02., earest hard- [FG. CO. y Avenue NN. as

POPULAR SCIENCE MONTHLY

if e , “What Do Chiropractors

HE temperature of a normal human body is approximately 98.6 degrees. You may sit in a room the tempera- ture of which is 80 degrees, or go out of doors when the thermometer registers zero and your temperature, if you are in health, will not vary a single degree, because, resi- dent in your body is an intelligence that generates, distributes and regu- lates the heat of the body, and instant- ly adapts it to the change in tempera- ture. If you start in June to take a plunge in the lake every morning and con- tinue it every day until December, this same power resident in the body will intelligently adapt the body to the seasonal change in temperature. This innate power gave the polar bear his long hair, that he might live in the land of eternal ice, and the gentle deer his speed, that he might escape his less swift foe. It is this power that in the struggle for exist- ence gave wings to the birds ani cunning to the fox, spots to the leop- ard and strength to the lion. It is this power that elongated the neck of the giraffe so that he could reach the high-hanging foods and for ob- vious reasons webbed the feet of the duck and goose. This inborn power adapted the stomach of the carnivora to a meat diet, the stomach of the herbivora to a vegetable diet, and the stomach of man to both.

ROM ANY ENT CHIROPRACTOR re ac. Te om 5 Aad F COMP o

b (~Vevl, y CY My WY esi \\) maintains its vigor and then —_ | j lets the house in which we live decay. During all the circling three-score years and ten it coordinates the physical functions, heals the body’s wounds, mends its breaks, adapts it to the change of season, occupation and pursuit and performs the miracle of changing common food into living, breathing, sensate bone and flesh.

slowly This power develops the body from a blastoderm to its full growth in thirty-five years; for ten or more it It laughs at all our efforts to locate it or to imitate its work and yet

HUMAn some people, because they cannot find ~ BRAIN — it, weigh it or measure it, question OR its existence and say “Vital force is Dynan? gsc aa On i a chemical phenomenon. Call it what you will, it’s there—a rose by any other name is just as sweet.

This “power within” Chiropractors call Innate Intelligence and all their philosophy, scienre and art is built upon this fundamental fact. They teach that “Innate Intelligence” func- tions through the brain and nervous system, and that disease is but the abnormal exysression of one or more of the nine primary physical functions. Any pressure of a harder tissue (bone) upon the soft nervous tissue, impairs the conductivity (function or work) of that tissue and results in disease. All that is necessary for a complete res- toration to health, is that the imping- ing tissue be adjusted to normal posi- tion, which permits the nerve again to function normally, Scientists call the modus operandi of the the law of adaptation. professions engaged in getting the sick well, chi- ropractors alone recognize the exist- ence of the thing itself, and the law of its expression, through the nervous system. “power within” Among the DEFINITION » he practice of Chiropractic consists of the palpation and adjustment,with the hands, | of the movable segments of the spinal column to normal posi- | tion for the purpose of releas- | ing the prisoned impulse, That is the reason Chiropractic suc- ceeds where all other methods fail.

ae <—_ Write for information regarding Chiropractors or Schools to the Universal Chiropractors’ Association Davenport, Iowa, U.S.A,

—) ———

—_— *

aS oo

See All Rights Reserved

Page 104

128 [ | ¥ i Ss . A ii es '| MU-RAD LABORATORIES 8 * evan the greater heights of this la- test Mu-Rap achievement, larger possibilities for radio entertainment are brought within your reach. The new MU-RAD RECEIVER MA-15, com- bining the famous Mvu-RAD simplicity of operation and electivity, with loud Guaranieed ae 1000 Ail Inc. 11 Fifth Avenue Asbury Park eB speaker volume and clarity, is designed specifically for long ranges, with only a two foot loop. ance. of Three stages of radio frequency ampli- fication, with detector. “say Volt-meter for instant and Well balanced appear- readings “B” battery condition. | strips of cloth and left to dry. | later drilled through both leather and A Coal-Saving of at least 20% is Guaranteed to every user of the Guaranteed in this case means just what it says. There’s no hokum about it, no “ifs” or ‘buts.’ Properly attach the CROWN Fuel Saver to the feed door of your heating plant and we guarantee you an actual saving in fuel of at least 10° —or 7 will refund your money without question Many users of the CROWN obtain fuel savings up to 50% Over 10,000 satisfied users of the CROWN ar tting more heat, steadier heat and cleaner heat They are cutting down their coal bills ! to eliminat- ng smoke and deadly gases; and_ re- ducing the number of trips to fire the furnace What the CROWN is The CROWN is a small device which may be ea bolted to the teed door ot any type heating plant without injury to the door The CROWN (see illustra- tion provides by means natural dratt, an auxiliary supply of hot air over the surface of the fuel bed This hot air (oxygen burns the rich gases that are ordinarily lost thru the chimney in the form of ‘‘smoke.”’ The CROWN turns this “‘smoke”’ into intense heat and assures almost perfect combustion. CROWN /ue/ Saver la Easily 1 AT FROM PER! MECOMBUSTION »> attached d ‘ Sy pp DAD, to the feed door of any heating plant The CROWN FUEL SAVER _ works automatically. There’s nothing to take care of; nothing to get out of order It is easily installed without putting out your lurnace hre. Write today for details Don't put off learning about. the amazing it-produci ind guaranteed coal-saving power f the CROWN Fuel Save Write today for details and prices and tor our In- teresting free booklet ‘‘Making the Coal Look Lik 30 cents.” As the CROWN ct s ~ give name and make ot heat i! plant and approximate size of grate, CROWN FUEL SAVER CO. 12 N. 10th St., Richmond, Ind. Distributors Wanted—Write for interesting profitabl proposition, Every home, business house and factory a prospect HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY a Leather Improves Traction of Small Iron Pulleys SERS of power-driven often find that belts that run on ; ing machines, which drive several sha through one belt. In such cases the sma iron pulleys can be made to grip the be] better if they are covered with leathe: ¢ . | Select a good piece of leather belting of suitable thickness and cut it so that when | it is wrapped about the pulley, it wil JOINT RA-~-COPPER RIVETS A piece of leather belting is cut to fit the pulley and fastened to it with sunken rivets short by 14 in. or more. sewing-machine belts. the face of the leather. Then soak it will stretch over the pulley. Wher place, it is bound with cord or narro iron and rivets placed as shown.—J. R. Seating a Small Ball Valve N MAKING or other valves where the moving pa is a steel or bronze ball, the importa: thing is to get the valve-ball well seated, | so that it will bear evenly all around ar be proof against leakage, yet free to move without sticking or binding. A simple and excellent way to attai this result is to form the seat first with countersink or specially ground tool having an angle of about 65 machinery leys of small diameter slip considerably, This is especially true in the case of thresh ts L\@i of | ne Fasten the ends with wire belt hooks, such as are used on Space the hooks evenly and hammer down the ends below the | leather in water for a few minutes so that Holes ar “ea small ball check valves, rt ~.HAM MER 3 of a | t |g put bend is a help ing while small work Mis ak squal is lar for su lean b la ben }a foo i—W. How T! CC ihas p |mute can | lroom. | i i | t d y a degrees, and then COPPER lightly hammer OR BRASS the ball into the ie seat, using apiece - VALVE BALL Mu of copper or soft ,--VALVE SEAT | brass as a buffer UYijpi4 bahia between the ball ¢ \l 16 | and the hammer. ° and ; | To be on the / tot | safe side, do not Hammering the ball iT use the ball with makes a perfect seat or sol which the seat if it is was made for the actual valve, but use 2 wie b Ff e fresh one, hammering it in as before, bul very lightly. good seat in brass. Nothing is gained by making the be ing surface too wide. A seating widt! 1/32 in. is sufficient for a ball 3/16 ir | diameter. A SERVICEABLE scraper for delicate ¢ | sures may be made from a draftsm: | broken ruling pen. This method makes a ver’ ar ing Simply grind to ‘ yveal or Spri Sprin: ofFast Ls! i bietur frame struct Wor id ras | knife edge the edges of that part of th#yitho blade remaining intact.—J. G. F. Bridg

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HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 129

= —_ i 4 Extra High Bench Is Convenient | | for Delicate Work hinery oF et I straightened up one day to

yn pul- relieve my back while constructing srably, |}. a delicate piece of cabinetwork, the idea thresh. |f. of a high bench suddenly came to me. I

shafts |) built one at once and now do the majority e smal] of my small he belt | puttering jobs ther, |§ at it. ting of | The bench is t when |) 3 ft. 9 in. high, will be |}, just right for me to rest my 5 elbows without bending. This aul is a wonderful FSO" if help in steady- | ing the hand = while doing Pa) small, difficult iwork. The top is about 3 ft. square, which

it the ; eae is large enough Doing w ruin: ; / ; riven Seen eee ae reeourin Build your own Radio Set! — can be done on — —and save half the lab es te €NCS Bia bench of this height. I have also placed “~and save half the labor customarily mgm: afoot rail about 12 in. from the floor. involved. Is below fi: F. MESSENGER, Stillwater, N. Y. The panels are completely drilled, and pie igor’ the parts are simply fastened with screws ;so that How to Make a Practice Mute and nuts. Then iy | 73 A oe for the Violin Any circuit desired may be employed. Rates wae pas practice mute for a violin was We have eight different types of panels. her and a — = The crystal black panel finish, together a | mute in position the tones of a violin with the concave dials, lend a pleasing ‘an hardly be heard in an adjoining effect — the absence of knobs giving a Talve Rey clean, flush appearance. © valves A metal tube is soldered on the top of You can build, or buy, a cabinet to suit ring part ordinary metal violin mute to take a your individual taste. nportant plug, which is shown partially withdrawn. it enetel ” In this case the yund and | - plug is a sec- aa tion of bar sol- der, but lead to attain would be as at with @ suitable. : The plug must fit per- HAMMER fectly; any vi- bration causes OPPER an unpleasant OR BRASS quality of tone. we I have found a = a eth z = a ee Gdikig tanceed EISEMANN MAGNETO CORPORATION JALVE - : partly withdrawn construction of William N. Shaw, President ae ae tube and plug 40 THIRTY-THIRD STREET, BROOKLYN, N.Y. y, (1/16 in. smaller at one end) desirable, o and it is well to wrap one thickness of Z soft paper around the plug. the ball The plug may be soldered in the tube

rfect seat soldered directly to the top of the mute, ifit is to be used for practice work only; but use af Ut by making the plug removable, the ales hutymute may also be used when desired as | kes a very§#2 ordinary mute.—LEsLIE H. PHINNEY, | Springfield, Ill.

arn to Mount Birds |) Learn at home to mount birds, ani- I pargain us jelicate era i ure frames, eet ally ° when the A new automatic and self-regulating device has | YA Why Pay Full Prices ‘ elle ‘tames are small and delicately con- been invented by John A. Stransky, 2063 Fourth Costs Nothing To See Any Diemond onat draftsm2” dstructed. The needles will not split the | St.. Pukwana, South Dakota, with which auto- Len, hone

g the bear ng widt!

||| Thie $/4—1/16 Ct. perfectly cut diamond, a snappy, blazing solitaire, at $42.65 among || bargains ‘in our lists. See the many big am- }} azing values some as low as $60.00 per A Carat, other higher per Carat bargains. This 75 year oldest largest Thamond banking

| bil } yy: 40 57 | il } Latest list n. Ne. cost to you aunt yr] | to ‘ . mobules have made trom to 5/ miles on a gallon }) ates Penn 55 foe, on pans. en ree. ik th ty ae can be a ssed “— place | of aapaiins. It es all cores — peavents | Detatt fives cab loam values. Cun'autoed. x: Ithout ammering.—ALBERT ORTE, spark plug trouble and overheating. t can be || Explains unlimited exchange vrivilege 3. F Bridgepe rt, Conn. oi installed by anyone in five minutes. Mr. Stransky | || JO% BeRoy&Sons, . 472700Roy Building oi. ) ( Opposite Post Office Pittsburgh, Pa. ————————— ae wants agents and is willing to send a sample at his own risk. Write him today,—Adv,

Page 106

MAZING NEW The Canadian Pacific of Easy Payment. This meet paymen Railw iy Offer make Under year's free and interest this use of the land without any interest. Alberta the vields of 50, 60, over previ 75 and 80 bushels were returned. »us years with equally high yields. NO TAXES ON IMPROVEMENTS Taxes are moderate and there are no taxes on livestock buildings, improvements, implements or personal effects. Good markets, modern schools, roads, churches, amusements make farm life in Western Canada desirable and attractive. Irrigated Jands in Southern Alberta are also for sale upon the same amortization terms as our other farm lands. Unfailing water supply, administered under Government direction. Full details on application. M. E. THORNTO s you a Farm Home in Western Canada on a New Plan S$ it pos sible to own a farm home without taking all profits to its and leaves a surplus for comforts and enjoyments. PAYMENTS EXTENDED OVER 35 YEARS— FIRST YEAR FREE USE OF LAND plan “5 you pay down is 7% of the purchase price- will be amorti: zed on an easy payment plan of 34 equal, annual payments which makes the second payment fall due two years after the purchase of the land, which is figured on the basis of 7% (including principal and interest) of the balance of the cost of the land. chase of 160 acres costing say, $3,000, the down pz ayment will be $ commencing at the end of the second year, will be $195 get clear title to the land—unless, of course, you wish to pay sooner, which is your privilege. CANADA’S 1923 CROPS BEAT ALL RECORDS In 1923 the wheat crop of Canada exceeded the 1922 crop by almost 100,000,000 bushels. average yield was 26.5 bushels per acre and there were many individual cases whe re ‘Shese enormous yields on moderate priced land even at average prics for farm products have placed many farmers on YOU CANNOT BUY UNTIL YOU IN order to trips from points Chicago and West will leave on Single fare plus $2.00 for the arrange on this new so easy that you can own your own farm home— instead of renting. SUPERINTENDENT OF COLONIZATION ° Room442, Canadian Pacific Railway Bldg., Calgary, Alberta HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY OF a) For exz ample, on a pur- 210 and the annual payments, At the end of 35 years you will —One The balance of principal A 30. In Other crops showed a corresponding increase he highroad to success. VESTIGATE You must inspect the land before buying in judge its fertility. Special inspection Tuesdays each month. round trip. Let us Send for complete information amazing plan. These terms are the first and third details. and FREE SPORTING GOODS CATALOG Write for our wholesale prices on football, basket ball and base ball, athletic goods. Free D & M rule book on all sports. Wholesale Distributors of Athletic Goods AMERICAN SPORTING GOODS CO. Jacksonville, Ill. AT YOUR DEALER’S COUNTER Buy a good Head Set. Good Head Sets must have Powerful Magnets, Powerful magnets ensure sensitivity, great volume of sound and true tonal quality. rhe power of Head Set magnets is easily te sted at your dealer's counter. Unscrew the cap on the ear piece. Place the thin circular diaphragm on the counter. & Hold the ear piece above it and see how far the . magnet will pick up the diaphragm. “a rhe farther the the magnet, pick up, the more y agit and the better the Head §S 1 Stromberg-Carlson Head Set will pick up its diaphragm at least one- fourth of aninch, Will yours? Stromberg Carlson Telephone Mfg. Co. ROCHESTER, N. Y. IAs Clear zen" Shin. Your Skin Can Be Quickly Cleared of Pimples, Blackheads, Acne Eruptions on the face or body, Barbers Itch, Eczema, Enlarged Pores and Oily or Shiny Skin. Write today for my FREE BOOKLET FREE ° ‘A CLEAR-TONE SKIN,” telling how $1000 Cash says! canclear your skin of the above blemishes. cured myself after being afflicted 15 years. E.S. GIVENS, 153 Chemical Bidg., Kansas City, Mo. Protect your tools A — fron th eft. Write any name,engrave Se Udy any gn on meta mic i like t or pen il. Co pre- a pai! anywhere nte restir ge des scrip tive circula free W.rite to-day Agents war iL. Arkograph Pen Co., 481-A East Couch St., Portland, Oregon “Worlds _Greates Written 2-Year Guarantee Your Proof of Performance START NEW YEAR RIGHT Thousa nds of Popular Science Monthly Readers will profit by this amazing offer They will buy tt famou = year guaranteed World Battery at » lowest price ever quoted, They will get their Find of a na TAbhes ind a B"' Battery or a nickeled Auto Spotlite FREI And they get the best battery built, with 2-year ironclad guarantee. Compare These Prices yunt for Cash with Order Radio Prices Special 2 “oo Five Per Cent Diace Automobile Prices Volt Storage Pi it- . 11 Plate - Ford, Chev., Mitche t. Elgin, Veli of 6 i . rdere e, Regal 6 Y Frank., Brise and Crow- 6 , Elkhart 6 Volt, 1 n 5 (rive year and model of car 6 Volt 14( reo ps. - 16.00 neon NO MONEY clip this ad. and mail with ecify w i be sh ipped t atte’ ang at the * Battery and and send your or « Get the ** Spo itl lite ¥ RE oy Clip the ad WORLD BATTERY CO. 1219 So. Wabash Ave., Chicago, IIl. : ickele Your Choice **°. JF — Dept. 7, Spotlight ser Battery and Hydrometer 4a Home Workshop Chemistry Simple Formulas that Fl Will Save Time and Money ——_—— F THE drying oils pounding and diluting paint, linseed used in com- oil is the most important. Before being incorporated in varnishes and paints, it is usually boiled and almost always diluted with turpentine. This makes it dry more rapidly, and it therefore serves as a drier, The best way of diluting paint is to add turpentine (spirits of turpentine will do), The addition of gasoline or petroleum, which is sometimes used, or benzol (benzene) is not to be recom- mended. They are just solv- ents and, Putty of linseed oil and having no precipitated chalk body, they evaporate, while turpentine oxidizes to a resinous product, which aids in holding and covering the surface. Five colors are required for mixing any ordinary shade of paint. These are black, white (zine white or white lead), lemon yellow, carmine, and Prussian blue. Mix- | ing a little black in the white gives a gray shade, although a trace of blue may be | helpful in accentuating the gray. Blue | and carmine give violet; yellow and blue, | green; yellow and carmine, orange. In| this way any bright or dull shade can be | mixed together in a few moments and | thinned with the turpentine and linseed- | oil drier. After use, clean paint brushes at once | with plenty of soap and water. If the brush is hard, let it stand overnight in a thick soap solution and clean next morn- ing. If the brushes are | rocklike, soften by plac- ing them in a glass or porcelain vessel con- taining 1 lb. of sodium carbonate (about 25 cents worth) in 11}% qt. | of water, which should | be kept lukewarm for about a day. The soft- ened brush can then be cleaned with soap and water. When it is nec- essary to keep a unl- Boiling a drier formly delicate shade, | it is best to clean the! brush further with benzol. | By boiling raw linseed oil (10 parts) with manganic peroxid (1 part) that has been thoroughly dried and placed in a bag | in the oil, a good drier is obtained. It can be taken as a rule never to add too much drier to a paint. A teaspoonful or so is sufficient to a pint. | Not long ago I required a drier imme: | diately and could not buy any because (Continued on page 131) i loc it i pos a st —I In b don one, by s D the nish The han can brus is dy

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hop y 1s th Time Money eee 1 Cf y m 2 drier, | to add | ill do) -oleum, | and alk Zes 1 hold cing Wie ind b nge. e can be ents -linseed- ym- | linseed | being ts, it is diluted any | e black, | , lemon ie. Mix- S a gray | may at re | | oa | ing be slue lue, | In | and | , at _ If ight xt morn- ushes are | the | in a n by plac: | . glass or | ssel cone | yf sodium | bout in 1}% qt. | ch should | & 25 | qt. warm for The soft- in then be soap and . jt is nec- | ep a uni- | ite shade, | clean the if (10 parts) | ) that has} od in a bag | ed. It can too much ul or rier imme- iy because | 1) so is —— a | Home Workshop Chemistry | (Continued from page 130) the day was a holiday. I placed less than half a teaspoonful of manganese borate, which I happened to have, in a pint of linseed oil, and brought the whole to a slight simmer for a quarter of an hour. When it was cool, I had a drier that would dry in 24 hours. It proved also to be an excellent and practically colorless varnish. A paint made up with white lead re- quires a slight amount of drier, but a drier is not added when red lead is used as a color, for red lead imparts drying proper- ties to linseed oil. When a non-tacky sur- face is essential, as for floors and chairs, a drier made with a lead preparation, such as red lead or lead acetate is to be pre- ferred over the manganese type. Raw linseed oil, which dries much more slowly than boiled oil, may be mixed with precipitated chalk and kneaded to a dough to form a putty that remains soft for quite a time. Runningboard Trunk for Long Auto Trips ee long auto trips, this runningboard trunk has proved most useful. It is 10 by 18 by 30 in., made of 14-in. white pine and covered with medium-weight imitation leather. The lid is 6 in. deep in front and 2 in. deep in back. The corners and edges are bound with zine cut in strips 34 in. wide and fastened with brass- This imitation leather-covered auto trunk fits the luggage carrier on runningboard | | | headed upholstery nails. One or two suit- case fasteners hold the cover shut, and a bes and handles can be added, if it is desired. |. W hile the trunk might be made larger, it ls commodious enough for average pur- poses and has the advantage of fitting into astandard runningboard luggage carrier. | —HARoLD JAcKSON, Kankakee, III. | | Improving a Cheap Paintbrush by Setting Hairs in Varnish | AT. TIMES, when a good paintbrush is not at hand and the work to be done does not warrant the purchase of one, a cheap brush may be made to serve by setting the hairs in varnish. Dip the brush so as to submerge all the hi air and work out the surplus var- nish while holding the handle down. Then let the brush dry for 24 hours, handle down and hair up. A wire holder can be made in half a minute to hold the p brush in this position while the varnish | 1s drying. —L. W. FEAGIN. HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY The home completely wired is ready for every convenience and comfort that Electricity can fur- nish. The book — “The Home of a Hundred Comforts” tells how to plan for a com- pletely wired home. Thousands have sent for it. Write for your free copy. Address Section P. 2 Merchandise Department General Electric Company Bridgeport, Conn. Super-service Wide-awake radio fans refuse to miss a good program because of storage battery weakness. For super-service they keep the battery fully charged from the house cur- rent with a Tungar. Likewise they use Tungar to charge the auto battery at home. The result is longer battery life and more “pep” —plus convenience. In homes with electricity Tungar recharges the run-down radio or auto battery over night at a saving. Sold by Electrical, Auto-accessory and Radio dealers. Tungar operates on alternating current. Two sizes $18.00 and $28.00 (60 cycle). East of the Rockies. GENERAL ELECTRIC 48-2 A $500 Cash Prize is offered for the BEST SECOND VERSE TO “REMEMBER” Those wishing to compete may receive a free copy of this song and rules of contest by addressing EQUITABLE MUSIC CORPORATION 476 State Theatre, N. Y. C. $21 ordering « factory says yu will =e Ree gp from -. Price, Ind, engines. reet, Magee Bidg., MAKE BIG MONEY Put Yourself on Easy Street Learn th trade and 1 ter the art of making beautiful sparkling, highly poli h v3 1arble, granite, agate, and turquoise, faced brick, buile dine blocks, oe table tops monuments and kindred products from common Port! and cement at one tenth cost. For full partic culars addr Master Cement Worker of the Worid, 433 W. 46th St. Los Ange les, Calif. STUDY AT HOME Become a lawyer. Legally trained men win high posi- tions and big success in ean ness and public life. Greater opportunities before. now than ever _— deps ende ent—be a $3, 000. to 310, ‘000 Annually We guide you B.. by Lao RC on, roa train at home during spare time. records anc letters from LaSalle at te SSmctedod to the bar in various states. Degree of LL. B. conferred. Thou- eands of successful students enrolled. Low cost, We furnish fall text material, ny E. ourteen- volume Law Libra: ary. Get cor valuable 126-p ‘Law Guide’’ and *‘Evidence’* books FREE. Send for thea NOW. LaSalle Extension cehvacetees Dept. 283-L, Chicago easy terms.

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HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Send for Andrews he knows—!”’’ “Seems to me that every time a tough problem comes up around here we al- ways send for Andrews. “Do you know why? It’s because he doesn’t guess at a thing—he knows! He studies those I. C. S. textbooks every chance he gets, and I want to tell you it has made him a valuable man for this firm. “This is the last time I’m going to ‘send for Andrews.’ For when he comes in to-day, he’s going to stay in. From now on he’s going to sit right in this office as my assistant. I wish I had more men like him.” OW do you stand in your organiza- tion? Are you a guesser? Or do you know? Make up your mind to-day, that you, are going to get the special training that you must have to get a better job and a larger salary. One hour a day, spent with the Inter- national Correspondence Schools, in the quiet of your own home, will prepare you for the position you want in the work you like best Mail the Coupon To-day! too, INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7673-C, Scranton, Penna, Without cost or obligation on m y part, please tell me how I can qualify for the position o in the subject before which I have marked an X BUSINESS TRAINING COURSES [] Business Management (1 Salesmanship jIndustrial Management LL) Advertising Personnel Organization LJ Better Letters _})Traffic Management (1 Show Card Lettering Business Law C] Stenography and Typing Banking and Banking Law {_] Business English Accountancy (including C.P.A.) (] Civil Service Cost Accounting CL) Railway Mail Clerk Bookkeeping {_] Common School Subjects Private Secretary (_) High School Subjects Spanish D French C) Illustrating TECHNICAL AND INDUSTRIAL COURSES (JElectrical Engineering 0 Architect [ jElectric Lighting () Blue Print Reading [ }Mechanical Engineer He ontractor and Builder [}Mechanical Draftsman Architectural Draftsman Machine Shop Practice Concrete Builder Railroad Positions Structural Engineer [}Gas Engine Operating Chemistry () Pharmacy Civil Engineer Automobile Work Surveying and Mapping 8 Agriculture and Poultry Mathematics Airplane Engine Metallurgy 06 Mining Steam Engineering () Radio Name Street Address City Occupation Persons residing in Canada should send this coupon to the international Correspondence Schoola Canadian, Limited, Montreal, Canada Th V tP k EF simple and e es 0c e concise method BOOKKEEPER 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 and business man, by F. M. size 3 x 6 inches, artistic cover, $1.00 post paid. POPULAR SCIENCE MONTHLY 225 WEST 39th St., NEW YORK novice Pay ne; 160 pages, | squares Inlaid Serving Trays Made with Cigar-Box Wood By M. W. N ATTRACTIVE serving tray with an inlaid effect can be made by saw- ing the wood of cigar boxes into small pieces and gluing them on a thin base to form a pattern. Tear apart several cigar boxes and re- move the paper covering by soaking and scraping. It will be found that some boxes are of cedar or similar wood having a beautiful grain, while others are poplar or other white or nearly white wood with very little grain. Sort the pieces of wood Lowry An‘ inlaid” bottom before framing Ghouns and a tray with another pattern (below) according to color and grain, and dry thoroughly. The usual size of these trays is 11 by 17 in. The pattern should be worked out to conform to these proportions. A good way to start is with a panel of dark wood in the center 3 by 9 in., which will leave 4 in. on all sides to be filled in. The de- sign can be worked out with alternating light and dark woods in squares, triangles, rectangles, and other shapes, according to the designer’s fancy. A few sheets of cross-section paper are a great aid in laying out the pattern. Let the large repre- square inches and fill in by shading the portions that are to be dark wood. The direction of the grain can also be indicated, Detail of tray mold- and a good ing and _ handles working plan made. When one gets started, numerous patterns suggest themselves. For the base on which to glue the pieces, select three-ply veneer or a piece of thick, heavy pasteboard or wallboard about 14 in. thick. This should be left a little larger (Continued on page 133) sent Beautiful Rocker Over 1000 other Cozy Home Furnishings Latest styles Just what you need now. Save big money at our low Factory-to-Family prices, Pay as little as §3 down; a year and ahalfto pay balance. Get all your Furnishings at once—pay as youuse. Thousands buying this new way Big Catalog FREE “Larkin Book of Bette or Homes.’ Shows everything for parlor orch, dining-room, bedroom, kitchen argain Prices on famous Symphonol Phonographs. Also Symphonic Pianos Player-Pianos in genuine Mahogany, Wal nut, Fumed Oak. Free trial. Up to 4 years to pay. Satisfaction or money back Check below article interested in, (1 Home Furnishings O Pianos or Players 0 Phonographs Cut out thfs adv.—write TO-Day for FREE Book. up to New Spring Ltthttt CO tac. Dept. 240, BUFFALO, N. Y. Peoria, Ill. Chicago, Ill SEND NO MONEY 2 GENUINE PeTETIaTN LS ss m3 Each (Cut Stones— No Chips) Solid Gold $25 14 Kt. White Gold Top, Gold Initial or Em- blem Inlaid in o Genuine a ¥ 6 m 8 W ee Hope Ruby 7%: «i Sit Es CAN ALSO BE HAD IN GENUINE BLACK ONYX Can be had in all initials (Old Eng- -3 lish); also in all * lodge emblems. Send size of finger and ring will be sent for inspection. Buffalo Jewelry Mfg.Co., “The Mail-Order House” Dept. A, Brisbane Bidg., Buffalo, N. Y. mdk35 2g Weeki Make $75.00 a week and up, selling our fine made-to-measure,all-wool suits at $31.50 retail, direct to wearer. Biggest values — Positively sell onsight. Biggest commissions paid in advance. We attend to delivery and collections. 6 x 9 swatch samples—over 100 styles all one price —furnished FREE, Write at once. W. Z. GIBSON, Inc, “chert 161 W. Harrison St., Dept, B-25 oneane a. BLANK CARTRIDGE PISTOL tection against Burglars, —” & Dogs PRICES as fife Ts takee ¢ reece ity 31,00 post- whnje pabrice sesaces” by express, SOc per 100. d Johnson Smith & Co., Dept. 56, Racine, Wis. F

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for iful cer styles {ny ] ohn Davey organization “| | needs young men up to shings Vv way EE Better parlor itchen ings John Davey’s organization, The Davey Tree yers Expert Co., Inc., has a limited number of open- ings for ambitious young men between 20 and 30 years of age, single men preferred. The opportu- 0-DAY nity is unusual, offering good pay at the start, permanent e mployment in the Davey organiza- tion, and thorough scientific training in the pro- fession of Tree Surgery Advancement rapid, according to merit. The work is fascinating, of- fers chance to travel extensively, and association with fine fellows. Only clean, red-blooded young Americans, lovers of the outdoors, need apply. Write, giving full information to The Davey Tree Expert Co., Inc., 55 City Bank Bldg., Kent, Ohio. J ewel - | Bur aoa i Any Letter ntlees you e diamonds Only sf 2° Down The 21-Jewel Burlington fs sold to yon at a very fow price and ms the very x epecens terms of $1.00 d down—tres’ equmnation— wed ¥ payments after acceptance. Send today for Send for te most complete watch book ever ook produced esigns and engravin 3 bean- dfally tees S a 1OWiite for it today, It is free, A letter or a postcard will Burlington Watch-Co. Beptas-e2 chicane Big Value for 10 Cts. 6 Songs, ag and music; 25 Pic tures Pretty Girls; 40 Ways to Mak Money; 1 Joke Book: 1 Book on Lovi 1 Magic Book; 1 Book Letter Writ ing; 1 Dream Book and_ Fortune Teller; 1 Cook Book; 1 Base Ball Book, gives rules for games; 1 Toy Maker Book, Language of Flowers; 1 Morse Telegraph Alphabet; 12 Chemical Experiments; Magic Table; Great North Pole Game; Conundrums; 3 Puzzles; 12 Games; 930 Verses for Autograph Albums. All the above by mail for 10 cts. and 2 cts, postage. seinon SALES CO., Desk 161, South Norwalk, Conn. [MAKE MONEY - AT HOME OU CAN make $1 to $2 an hour writing show cards at home in your spare time. Quickl and easily learned by our new simple pain wr § 0 canvassing or soliciting. Weshow you how, guarantee you work at home no matter where you live and pay you casheach week. Full par- ticulars and booklet free. Write to-day. MERICAN SHOW CARD SYSTEM LTD. Authorized and Fully Paid Capital, $1,000,000 206 Adams Bldg. Treen,’ Canada cine, Wis. F HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Inlaid Serving Trays (Continued from page 132 than the tray is to be and should be tacked around the edges to a wide board, so that it will be held straight until the bottom is finished. When the selected wood has cleaned and dried, it is cut with a miter box and fine backsaw into pieces of the desired shapes and sizes. The edges are smoothed off with fine sandpaper. The pieces are then glued to the base, care being taken that they fit quite closely, with good joints. They must be braced from the sides till the glue sets or they will creep apart. Where a line of small pieces are put on next to a large piece, it is best to put on the small ones first, as far as possible, as it is easier to fit the one large piece than the many small ones. When the glue is dry, dress off the sur- face with a sharp plane until smooth. Finish with fine sandpaper, and oil or wax the surface. Wax brings out the grain beautifully and gives the wood a very rich appearance. The edges are then trimmed to the correct size. Tray Frame and Handles The framing can be done by any picture-frame maker, who usually will have molding suitable for this purpose. If it is desired to have the whole tray handmade, the molding can be made from been birch, maple, gum, mahogany, or walnut strips 2 in. wide and 34 in. thick. Cut a rabbet along one edge to receive the bot- tom of the tray and bevel and round the inside edges. Leave outer edges straight. The handles are cut in the end pieces by boring two 34-in. holes 234 in. apart from outside to outside and chiseling out the wood between. Put the frame gether and varnish with mahogany or walnut varnish stain, finishing with a coat of clear hard varnish. Then insert the bottom under a piece of glass, fastening it in with tacks. The under side of the should be covered with felt. to- whole tray FEATURES FOR MARCH How to make— A neutrodyne radio receiving set. Inorder to obtain the best and clearest article yet written on assem- bling a neutrodyne set, PopuLar ScrenceE Monrtury turned to Prof Louis A. Hazeltine, the inventor. He has lent the services of John F Dreyer, Jr., Chief Engineer of the Hazeltine Research Corporation, for the preparation of this important feature. A Chinese game table. Now that “punging” and “‘chowing” have be- come one of the most popular indoor amusements, George F. Kaercher has designed an especially convenient and attractive table for playing the game and it can be made at relatively small cost. New furniture from old. A built-in buffet. A combination bench saw, boring and molding machine. Also there will be, as usual, articles in practically every field of interest to home workers. will be the talk of all your friends if built with Kellogg radio equipment. Volume, clarity and satisfaction will reward your efforts. Every’ Kellogg radio part is accu- rately and carefully built for its specific purpose. Every piece of metal, insulation, etc., that goes into the making of the completed parts is the best that money can buy. Kellogg Rheostat 6 or 25 ohms The popularity of $1.50 Kellogg at the Chi- cago Radio Show proves that the demand is for a high quality prod- uct in radio as well as in everything else. Demand Kellogg and know you are getting the best— Kellogg Transformer experimenting with 4tol or 34tol jnferi P niles or 372 inferior apparatus $4.50 distr is expensive and discourag- ing. If your dealer can- not furnish KELLOGG write or Kellogg Variocoupler With Coil, $13.00 , f wire us his name and address. Kellogg 43 Plate Variable i y fa) Condenser a ug ‘ " head fier HEY With Vernier a ae Sy $8.79 (Trade Mark) Built and Guaranteed by KELLOGG SWITCHBOARD & SUPPLY COMPANY CHICAGO, ILL.

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136 134 Your Choice 75c a Week We have cut the price one-half No matter what your occupation, one of the home study sets listed below will quickly fit you for a better job and bigger pay. Any set you select will be sent for seven days’ examir ation, and if you decide to buy you may pay the rock bottom price at the rate of only 75ca week. But you must act now! The rising cost of paper and binding materials won't permit us to continue the present low prices much longer. The books are the work of recognized author- ities They are written in plain, easily understood language, by recognized authorities, and contain hundreds of photographs, diagrams, tables, etc.,that make difficult points as sim] le as A-B-C. Hand- somely nd durably bound in half or full morocco leather (ex xcept as noted), end prtincale in gold, Pay-Raising Books At Greatly Reduced vhiaueam Business Management, 8 vol., 2500 pz Lge 1000 pictures. Wi e579. 56.., .. Vow 7 $29.80 penny and Centendtinn, 5 vi ‘olume . 138 pages, 1000 pictures. Was$37.50, N« 19.80 Civil Rnqinocring, 9 volumes, 3900 pages, 3000 pictures. Was $67.50 .Now 34.80 Electrical Engineering, 8 volumes, 3800 page 600 picture Was $60.00..Now 29.80 Automobile Engineering, 6 volumes, 2600 pages, 2000 pictures as $45.00..Now 21.80 Machine Shop “saber 6 volun ies, 2300 page 2500 pict . Was $45.00..Now 21.80 Steam and Gas Enginee ring, 7 volumes, 3300 pages, 2500] ires. Was$52.50, Now 24.80 ae and Renctios W ith reading course), 13 olumes, 6000 pages, illustrated. Was $97 50 ....-Now 49.80 Fire Prevention and Insurance, 4 vols., 1500 pages, 600 pictures. Was $30.00, Now 14.80 Telephony and Telegraphy, 4 volun 1728 pages, 2000 picture Was $30.00 LC a ee oe 14.80 Sanitation, Heating and Ve ntilating, 4 volumes, 1454 pages, 1400 pictures. Was | BS re Now 14.80 Drawing, 4 volumes, 1578 pages, 1000 pic- tures, blue prints, etc. Was $30.00..Now 14.80 Send No Money Shipped for 7 days’ Trial Yes, we'll gladly ship any set right to your home or office upon your simple request. Pay only ship- ping charges when the books arrive. Don't send a penny until after es have used them seven days, then remit only $2.80 or return them at our expense. Pay balanceattherateof $3.00a month—75c a week. Act now—while these splendid books are being offered at 20% to 50% less than regular prices. This offer is open to every person within the boundaries of the U. S. and Canada. Grasp your opportunity— fill in and mail the coupon now. American Technical Society, Dept. X-220, Chicago , American Technical Society, Dept. X-220, Chicago, U.S. A. { | Please send me set of cane | for 7 days’ examination, shipping charges collect. | 1 will examine the books thoroughly and, if satished, | will send $2.80 within 7 days and $3.00 each month, | until I have paid the special price of If I decide not to keep the books, I will notify you at once and hold them subject to your order. Title not to | pass to me until the set is fully paid for I a i lg tienes isms il tiara bac | | ee erecccccccccececcececece~---- | Employed by ony ROAR I HOME HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY i Keeping the Home j Shipshape How to do the odd jobs that save time, temper, and money To INSTALL a transformer for op- erating a doorbell with electric current from the lighting circuit, first determine the voltage of the line (usually 110 or 220 volts). Then buy a transformer that is suited to that voltage. The voltage on the secondary or door- bell side of the transformer may be six or 12 volts or two or three different volt- ages. If the latter type is obtained, it will be possible to draw one voltage for one purpose and an- Doorbell Transformers to all connections of a similar sort wires should be cut longer than necessary and the extra amount wrapped several times about a pencil toform a coil. Then, if a connection should break, there stil] will be enough wire to reconnect without making another splice or using new wire. One of the best places for the trans- former is on the under side of the first- story floor, if the home has a basement. Since it does not require attention, it js out of the way there and when properly installed is perfectly safe and foolproof. Many installations, the other for another purpose—as 12 volts for the doorbell and 24 for a 24-volt motor. Therubber-covered wires leading from the transformer shown in Fig. 1 go to the light- ing line. The bind- ing posts on the top are for the bell con- nections. This photo- diagram shows a standard hook-up of transformer, bell and button. however, are made in the fuse box when the box is of sufficient size for the purpose. How a small trans- PORCELAIN TUBES Thy T a | Hii iH Wit ‘pg LU SBESTOS a To conform to the requirements of the Board of Under- writers, the following points must be observed and in making the installation: All joints or splices on the line side must be soldered after the wires have been scraped, then wrapped with rubber tape and the whole covered with friction tape. The transformer must be placed on a sheet of asbestos of approximately three times the area of the base of the trans- former and, while not absolutely neces- sary, the wires leading to the bell should be rubber-covered. When making connections (this applies Fig. 1. earried out Photo-diagram of the doorbell cir- cuit using a transformer instead of batteries former, such as the one just de- scribed, can be installed in a box of its own is TRANSFORMER indicated in Fig. Fig. 2. Transformer Ae The coffee in asbestos-lined can can, which has a tight cover, is fastened to the wall with screws. The inside is lined with asbes tos and porcelain tubes, or bushings, are used where the wires pass through the tin, at least for the lighting circuit. OW do you keep your home ship- shape? For the best letters containing practi- cal, novel, and ingenious ideas on this subject, Poputar Scr—ENcE MontTHLy will give a first prize of $25, a second prize of $15, anda third prize of $10, and will purchase at space rates as many other contributions as are available for use in the Shipshape Home columns. Take for your title, “How I Keep My tome Shipshape.”” Tell your own ex- perience—what you actually do in the way of woodworking, painting, and varnishing, wallpapering, plumbing, and $50 FOR SHIPSHAPE HOME IDEAS of your house or apartment and describe them in such a way that other readers | will be able to make profitable use of the same methods. This isa contest intended primarily to help the other fellow. Keep your letter short—not more than 400 words. Inclose photographs or pen- cil sketches, if possible, to illustrate the ideas or methods. | The competition will close February 20. The winning letters will appear in the June issue. The contest will be judged by the Board of Editors and their decision will be final. Unavailable letters will be returned if accompanied WORKSHOP DEPARTMENT OF POPULAR SCIENCE inv me! avo sto] rep: 7 gra par teri air | cas due the ter of | duc five thei wit} box resu roor T by ¢ the patl stov piec crac help fi usag shay man woo cTOss reme kept wher back For close weds hold W Set { ordir Wooc W upon hand | push boar to th hot | heay Push some the like. Don’t simply catalog a number _ by stamped and self-addressed envelopes of odd jobs. Pick out one or two of your Address Shipshape Home _ Editor, | own ideas that have been particularly Poputar Science Monrtnty, 225 West successful in reducing the upkeep cost 39th St., New York. MONTHLY

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ort) the 2cessary several Then, ere still without eW wire, e trans- he first- isement. on, it is properly ol proof. llations, made in x when sufficient purpose. all trans- sformer ned can wall with th asbes hings, are ough the uit. LS escribe | ‘eaders | of the tended re than or pen- ate the -bruary pear in will be id their railable ypanied relopes Editor, 5 West close to the edge of the blade. not be tapered down. HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 135 The Shipshape Home (Continued from page 134) deena mr “- Stoves and fur- Repairing naces frequently de- Furnaces velop cracks and these sooner or later involve costly and troublesome replace- 'ments. This expense often may be avoided or indefinitely postponed by stopping the progress of the crack and repairing the break as soon as they appear. The photo- graph shows part of the in- terior of a hot- air furnace with cast-iron air ducts resting on the firebox. Af- ter a few years of service, the ductsdeveloped five cracks at their junction with the fire- box, with the result that coal-gas escaped into the rooms above through the air pipes. The progress of the cracks was arrested by drilling a small hole just a trifle beyond the limit of each one and in the line of its path. These holes were tapped for 14-in. stove bolts, which were used to hold pieces of heavy galvanized iron over the crack. Furnace cement under the patches helped to make them gastight. The furnace has survived two winters’ usage since being repaired and is in good shape.—O. S. MARSHALL, Springfield, Vt. Two patches inside hot-air furnace SkiLt in the use of both wood and iron planes has to be acquired. A great many men earning their living with woodworking tools cannot clean up a cross-grained, brittle piece of wood ina thoroughly workmanlike manner. Tearing the wood is perhaps the most common fault of the home worker. This means that rough places are left on the surface, especially around knots. To remedy this the cutting blade must be kept sharp. It must have the right taper when ground in the first place and the back iron must fit down tightly and snug. For fine work the back iron should be The wedge or cap iron must fit tightly and hold the blade firmly and solidly. With a sharp, properly adjusted plane set fine, any one should be able, with ordinary care, to clean up cross-grained wood, When planing, pressure should be put upon the front of the plane with the left hand. The right hand is used only for pushing, except at the very end of the board, when the pressure is transferred to the rear handle so that the wood will If a plane were heavy enough, it only would need to be Planes and Planing | Pushed, but as chey usually are light, Some pressure is required, and practice soon teaches how much this should be. If, after taking a few strokes, the plane chokes up, it will be because the above Precautions have not been taken or be- (Continued on page 136) NTIS TRADE MARKS COPYRIGHTS PROTECT YOUR IDEAS ANY NEW article, machine, design or improvement thereof, or any new combination of parts or improvements in any known article which increases its efficiency or usefulness, may be patented, if it involves invention. If You Have Any New Ideas which you feel are useful, practical and novel, take prompt action to protect your rights. If you have invented any new machine, or new combination of parts, or improvement, or any new design or process, SEND DRAWING, MODEL OR DESCRIPTION of it for intormation as to procedure to secure protection. Write Today for Blank Form ‘Record of Invention”’ USE THE COUPON attached, and immediately upon its receipt I shall send you this form to be returned to me with drawing, description or model of your idea; promptly upon receiving your idea I shall write you fully as to procedure and costs, DRAFTING and SPECIFICATION ROOM of CLARENCE A. O'BRIEN, Registered Patent Attorney, Washington, D. C. No Charge for Above Information All communications are held in strict confidence. My personal, careful and thorough attention is given to each case. I offer you efficient, reliable and prompt service—based upon practical experience. Highest references. WRITE TODAY for free book ‘‘How to Obtain a Patent.’’ This book will give you valuable information. and it may save you much time and effort. Send for it NOW. My practice is devoted exclusively to United States and Foreign Patents and Trade Marks. Write me freely, frankly and with full confidence; it is very probable that I can help you. Write TODAY. LARENCE A.OBRIEN REGISTERED PATENT ATTORNEY MEMBER OF THE BAR OF SUPREME COURT OF UNITED STATES, COURT OF APPEALS DISTRICT OF COLUMBIA, SUPREME COURT DISTRICT OF COLUMBIA, UNITED STATES COURT OF CLAIMS, Practice Confined to Patents and Trade Marks 88-B Security Savings & Com’! Bank Bldg., directly across street from U.S. Patent Office, Washington, D. C. CLARENCE A. O’BRIEN, Registered Patent Attorney, Washington, D. C. 88-B Security Savings & Com’l Bank Bldg., directly across street from U. Patent Office. Please send me your free booklet ‘‘How to Obtain a Patent”’ and blank f of Invention”? without any obligation on my part. NAME ADDRESS... (Write clearly) HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 137

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HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 2] Jewel ~ Extra thin TUDEBAKER The Insured Watch © > Direct from the Maker Ca ~~ Zale vA mga PRSIEEE TRY woe Ui “ff } ‘ Ty \ Nf | As0 AF 10°) New CF Ean ied BS: Model) eres Extra Y ENT FOR pown! Only $1.00! The balance in easy monthly payments. You get the famous Stude- baker 21 Jewel Watch—Insured for a lifetime; a choice of 54new #4 Art Beauty Cases; 8adjustments, ae including heat, cold, isochronism 7 and 5 pos itions—direct from the maker at lowest prices ever named on equal quality : Write today for FREE BOOK of Advance Watch Styles. Fine Chain FREE! For a limited time we are giving away FREE with every Studebaker Watch a beautiful pattern Stude- baker Watch Chain, Write now while offer lasts, Mail Coupon for FREE Book of Advance Watch Styles Send at once and get a copy of this bbok—FREE! See the newest, beautiful, advance styles in Stude- baker Art Beauty Cascsand Dials. Read how you can buy a 21 Jewel Studebaker Insured Watch di- rect from the maker—save big money—and pay for it on easy monthly payments. Stal for our free book. It Write! will post youon watch styles and watch values. Send coupon at once. Get Free chain offer today while it lasts, Studebaker Watch Co. The Shipshape Home | (Continued from page 135) cause some imperfection in the mouth of the plane holds the shaving instead of allowing it to curl out easily. By careful observation the cause often may be found and remedied. If you find slight marks or lines on the work, it will be because the cutting iron did not have the corners slightly rounded when sharpened. This always should be done.—A. E. E opr PLumMBING _ repair Repairing bills often can be avoided if the home Flush Tanks worker will take the time and trouble to do the work himself. Recently our plumber condemned the flush tank in our bathroom and said that a new one would have to be installed at a cost of from $15 to $20. I was con- vineed that I could make the old tank work practically as well as new with about an hour’s work and 10 or 15 cents expense. Our ball valve was of the old type with rubber collars that continually stretched By making and let water leak through. VALVE. LEVER ~*-NEW RUBBER BALL ~~--VALVE SEAT Two. simple repairs to a flush tank that saved a $15 or $20 plumbing bill the sheet-brass guide shown, I was able to substitute a rubber ball of the standard type. Another difficulty was that the float would not always act certainly, the plumber’s diagnosis being that the valve parts were so worn out as to be useless. The difficulty really was that the valve lever jammed against the socket of the float lever when the float had reached a certain point while rising. This was remedied quickly with a round file, so Dept. 232 South Bend, Ind. ae STUDEBAKER WATCH CO. Dept. 232, South Bend, Indiana Please send me your Free Book of Advance Watch Styles and particulars of your $1.00 down offer, EPP EPS Te Ear OTERO re A RS Se cue awning wad. coed woe ee Mawes Ra ele we vbl ee ee State.. who derive larg. est profits know and heed certain simple but vital facts before epplyi ng for Patents. Our book Patent-Sense gives those facts; free. Write Lacey & Lacey, 648 fF St., Washington, D. C. ESTABLISHED 1869- Superior Automobile Trouble Light Only $1.00 postpaid or C.O.D. if you wish. Made of the highest grad naterials, furnishe d in either single or double contact, complete ith 10 ft. cord, 2 c.p. bulb, guard and socket. Order yours today. INSTITUTE MFG. CO., Dept. 302, 311 Main St., Worcester, Mass. that there was ample play between the two levers. The parts were not worn out at all and the flush is now good for a life- time’s usage.—O. S. M. A COILSPRING about 2 ft. long and 1 in. in diameter is useful in cleaning the clogged trap of a sink, lavatory, or bathtub. Pull out one end of the spring until it looks like a corkscrew, and make Cleaning Traps Fits Anywhere HE same range of reception for whi you now require a 100 foot or lons aerial—infinitely improved upon by t Warren Radio Loop that fits into a co pocket. Interference eliminated. Sele and tunes with remarkable ease and accu racy. All enclosed by Bakelite shield Four compact sizes for every purpose. The best known—the best liked. Write for the name of the nearest Warren dealer and Bulletin U-102 A TYPE FOR EVERY SET Type-A-737 (300- 700 meters) 6 inches ane nae s é 10 irectional Type-A- bea ai 5s “1000 meters) 6 inches square— non- $ e 12 al Type-B- 2537" C800. 700 meters) 18 inches square— direc $20 Type-BL- 2520 (2 300. na, 000 meters) with honeycomb coil mounting, 18 inches square—directional - $25 Send for Bulletin U-102 V-DE-CO RADIO MFG. CO. Dept. O, Asbury Park, N. J. a loop in the other end large enough so that a wooden rod or peg will slip through it. Then use the spring as an auger and | screw it into the trap through the clean- out opening. You can fish almost any- thing out of the pipes by this means, and it will sometimes save a plumber’s bill.—L. W. Freacin, Long Beach, Cal. To the Man With an lea I offer a most comprehensive, ex- perienced, efficient service for his prompt, legal protection and the development of his proposition. 7 | Send sketch, or model and description, | } Fe ae ee my for advice as to cost, search through “% m™ prior United States patents, etc. Pre- }ay liminary advice gladly furnished with- }® out charge. oo ca My experience and familiarity with & various arts, frequently enable me to [ff fe . 4 . vd * Fc accurately advise clients as to prob- 5 i able patentability before they go to rhe k any expense. a i" @ Booklet of valuable information and form |! tae «for properly disclosing your idea, free on aes | i bm request. Write today. bon 4 4 1% RICHARD B. OWEN | ' Bs Patent Lawyer f 6 Owen Building, Washington,D.C. 2276-D Woolworth Building New York City = aa greene ere nn Cheape pest Way to Go 2} to work orschooland recreationison it a Ranger bicycle. Choice of44stylesand f sizes. 30 Days’ Free Trial. Express prepaid. if desired. Saved 12 2Months to Pay time and carfare easily meets the small payments, Parts, equipment — et half usual rices.Send no money. Write, for our remarkable factory prices and marvelous ead Bree achitede © BUCHSTEIN’S FIBRE LIMB soothing to your st1 strong, cool, neat, !" Easy paym¢ toa for free catalog Guaranteed 5 Years Send for Catalog Today deformities P. BUCHSTEIN CO., 610-3rd Ave., So. Minneapolis, M sh mM: co sti ar ea

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i ee ex- |}s his }}# the i# tion, ough Pre- with- with ne to prob- z0 to form ee on for al deformities Ainneapolis, Mins Old Fountain Pen Barrel Supports Spider-Web Coil NEAT, serviceable, well-insulated support for a spider-web coil can be made from a discarded fountain pen. The pen and cap parts A and D are discarded. The penholder B is cut off as shown at line E-E. The detail F shows how the 5/16-in. panel is drilled. The holes will have to be shallower if the panel is less than 5/16 Fastened to a radio panel, the barrel of an old pen forms the coil support in. thick. Detail G indicates how the pen is bolted in place with a French oval head machine screw. Care should be taken to file off the corners of the nut so that they will come slightly below the root diameter of the threads K. This is so that the nut will not interfere with screwing on part C. The detail J suggests one coil arrange- ment, which may be modified to suit the inductance to be mounted. The type of coil used by the author is a self-supporting Reinartz inductance.—FRANK W. HARTH. Plumb-Bob Level Aids in Grading and Ditching aaa laying out ditches, terraces, fence rows, and the like, and measuring short distances, the level illustrated serves very well and can be quickly and cheaply made. The device is like a huge fixed divider or compass, with two 12-ft. legs made of straight and strong wooden strips. These are fastened exactly at right angles to each other and braced by a crossbar. A plumb-bob hangs from the juncture of the legs, as indicated and the cord swings opposite a scale marked for a few inches on both sides of the center of the cross arm. These graduation marks en- able one to give a ditch, terrace, or row a certain amount of fall by moving one of the instrument legs to higher or lower ground until the cord hangs directly in front of the desired mark. When it is necessary to measure short distances or lay off fence rows, the bob How the level is made and used should be removed. Then hold the level in both hands and swing it so as to de- scribe a series of semicircles, as in stepping off a line with dividers, but be careful, of course, to go straight. Only approximate results can be obtained this way, but they are accurate enough for ordinary farm | purposes.—B. KENNEDY, McCool, Miss. | » i ae lana hala HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY NO CHARGE FOR R O F F E a ® EXAMINATION AND #“ INSTRUCTIONS. HAVE YOU AN IDEA? YOUR FIRST STEP before disclosing an in- vention the inventor should write for our blank form bé . yy This should be Record of Invention signed and wit- nessed and returned to us together with model or sketch and description of the invention for examination and instruc- tions. No charge for the above information. Our Three Books Mailed Free to Inventors Our Illustrated Guide BOOK How to Obtain a Patent Contains full instructions regarding U. S. Patents. Our Methods, Terms, and 100 Mechanical Movements illustrated and described, Articles on Assignment or SALE OF PATENTS, Patent Practice and Procedure, and Law Points for inventors. Our Trade Mark Book Shows the value and necessity of Trade- Mark Protection and gives information regarding Trade-Marks and unfair com- petition in trade. Our Foreign Book We have Direct Agencies in all Foreign Countries. We secure Foreign Patents in shortest time and lowest cost. SPECIALIZATION Our Staff The field of invention is so vast that it is impossible for any one to become an expert in all the different classes of invention. For this reason Victor J. Evans & Co, employ a number of patent lawyers and expert draftsmen who have been selected for their special knowledge and ability in certain lines of invention. RADIO AND ELECTRICAL CASES A SPECIALTY All communications and data submitted strictly confidential. THE VALUE OF YOUR PATENT Will depend upon the skill and care with which your case is handled. neither time nor pains to secure the broadest possible patents. We spare We shall be happy to meet inventors in person at our offices or to advise them by letter, and they are at liberty to write us any time they desire information. careful consideration, an honest opinion and a prompt reply. Their plans will receive We have a personal interest in the successful outcome of every case we handle, and inventors can rely on receiving the highest grade of work and the most thorough service from us, WE REGARD A SATISFIED CLIENT As our best advertisement, and will furnish to anyone, upon request, lists of clients in any state for whom we have secured patents. Highest References—Prompt Attention—Reasonable Terms Free Coupon “—-WRITE TODAY: leeletenls | VICTOR J. EVANS & CO. Patent Attorneys New York Offices Philadelphia Offices 1007 Woolworth Bldg. 714-715 Liberty Bldg. Chicago Offices, 1114 Tacoma Bldg. Pittsburgh Offices 514 Empire Bldg. San Francisco Offices, Hobart Bldg. Main Offices: 760 Ninth Street, Washington, D.C. Gentlemen: Please send me FREE OF CHARGE your books as described above. el ... Address oo a ot ot a os os ol

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ere er RADIO Seoeeeeeeeel a ] | | | | CUNNINGHAM | PATENT || | RADIO TUBES NOTICE | | C-301A 5 Volts 1-4 Cunningham tubes are | | ampere filament, $6.50 covered by patents || C-299—3 Volts .66 amp | dated 11-7-05, 1-15-07, | Dry Battery Det. and | 2-18-08, and others | Amp . $6.50 | issued and pending 1] C-300 5 Volts _G is Licensed for amateur, || | Content Detec tor, $5.00 | experimental and en- || > 11 “ note sey teeta! | tertainment use in || “ee oe cy ee eand | vadto communication || Amp.Special Base, $6.50 | Any other use will be | jj C-12—Similar to C-11 hig : “i : | || withstandard buse, $6.50 an infringement, —_— eed Type C-301A gives gre tion with only ', Amp A, l, TUBES eater Power Amplifica-

Filament Current For Every Make of Receiving Set a cenneghan | the entire country today Cunningham Radio Tubes are recognized as the ideal tube for use in all makes of Radio Receiving Sets. The famous Cunningham C-301A Amplifier shown above is a high vacuum tube designed for use as an amplifier and detector containi: a new Tungsten Filament, the characteristics of which are long life, low power consumption, low operating temperature and greater amplification than any previous amplifier tube. Home Office: ASJu ; ~/' 182 Second Street 154 West Lake St., Chicago

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is fully explained in our new 40 page **Radio Tube Data Book.’’ Copies may be obtained by sending ten cents in stamps to our San Francisco office. Zio e This tube has a standard four prong base, and the glass bulb has the same dimensions as C-300 and C-301 rhe filament current is only one-fourth of the filament current of the previous type of Amplifier tube and it is, therefore, possible to use four of these tubes in a set without exhausting the storage battery any faster than when using only one f the previous types of tubes. The care and opera- tion of each model of Receiving Tube 30 Church St., News York

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We HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY ce Saving Money in Building | (Continued from page 81) | a a balustrade is set in place after it is | nd constructed, surplus should be allowed It for fitting. vill Another useful idea is the method ta | |shown in Fig. 2 of reversing plowed | window jambs of the double-hung type ° ‘he for use in casement or French windows. tal, | This idea can be used for windows open- Seven fy-Six } ears ApS | ing either in, as shown, or out, and is ise. much cheaper than the usual form of f P ® construction. t One other useful “kink’’ is shown in O rac (Ice | | Fig. 2. I have often found it necessary ; to make splices or mitered joints, and this HE firm of Munn & Company filed its can be done quickly and accurately by ; 3 . , : nailing the two pieces to be joined to- first application for a patent in 1846, and for gether temporarily and making a cut seventy-six years has endeavored to keep pace at random through both of them. This . . : : : ‘ . . a e . alli alaeneicatan a oileck 0k. with the inventive genius of the United St tes An experience of many years is at your disposal. Simple Wire Guards Prevent If you have an invention which you wish to Wringer from Jamming patent, send your sketches or model together IGHT pieces of clothing and linen with a description of your device, explaining | -~ often stuck to the wet rollers of the its operation, and you will receive prompt, LTS | power wringer on our electric washing | . ts | machine. They would wind around until courteous attention. ° | the machine jammed and this sometimes | * | tore the cloth and broke buttons, as well | Write for our Handbook on as putting much unnecessary strain on the gears. PATENTS To overcome this difficulty, I attached | four strands of No. 18 copper wire with | A full and complete booklet on Patents, Designs, Trade- and | | Marks, Foreign Patents, Copyrights, Labels and Patent ay, | | Office Practice with an explanation about our methods, , terms, etc. a. All communications strictly confidential een Keepin touch with the inventions of the world by reading are 414 SCIENTIFIC AMERICAN =| The MONTHLY MAGAZINE with a special appeal a to every man of inventive genius. Recent rulings of the -in. Patent Office, descriptions of the latest patented inven- in. | tions, legislation and court decisions affecting patents, pon | | are noted in this authoritative publication. RIN } The guide wires stop light articles from | MUNN & COM PANY clinging to the roll d clogging th i nging to the rollers and clogging them | Patent Attorneys | ° ° ° screws as shown to guard the upper and | 683 Woolworth Building, New York City lower rolls. After they were in place, I | Scientific American Bldg., Room 3, 625 F Street, Washington, D. C. dis- started the wringer and screwed the | “14: . c . we : 801-D, Tower Building, Chicago, Ill. nia- | upper roller down tight. The wires cut 02 H Blde.. S F : “al > an into the soft rubber about 1/32 in., enough | " anert Hidg., Sen Francisco, Cal. t on to hold them in place. > of | The device has worked well not only on our Own wringer but on several others eing | to which I have applied it. The wires do le is | no damage to the clothing and the buttons = - 7 — ee a ae iat SO ' will not catch if they are turned in as is —— 9s always required in using a power wringer. yf | —WALTER T. MARKowskI, Camden, N.J. NV ENTO RS PROTECT | OUR IDEAS ‘Combination Ink-Pencil Eraser Send for our Guide Book, HOW TO GET A PATENT, A | Removes Rust from Knife and Evidence of Invention Blank, sent Free on request. Tells VASE HAVING a gold penknife, the blades of our terms, methods, etc. Send model or sketch and description of which were becoming ruined from your invention and we will give p—- - = -------------—- e+e == ---| non-use and rust, the writer cleaned the our opinion as ¢o its patentable } ei | as steel with an ordinary combination ink- nature. _ le of | pencil eraser. The rust quickly vanished { ee hed, | ep being rubbed with the ink part of RAN DOLPH i co. Sein eect the eraser, and the pencil part of the . i | eraser polished the blades. —ic. M4. | Dept. 130, Washington, D.C. : «™ a

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140 SMASH Your Way Through to SUCCESS! ! FE’S race is to the STRONG. The fittest survive. The weakling perishes. Your Success in business, in society, in all the re- lations of life, depends fundamentally on your Physical Health and Strength. If you have some physical weakness gnawing at your vitals and robbing you of the very essence of success, you are a beaten man. You Can WIN Life’s biggest prizes are YOURS if you have the Physical Power to DE- MAND them. Where do you stand? Are you Lionel Strongfort a_ business drudge—one The Perfect Man of the ‘Yes, Sir’ boys, humbly taking orders from others who haven't half your ability but who DO have a surplus of Health and Energy? Or—Are you the fighting, pla: ig, DOING sort of MAN—the man who leads and directs other men—the man who is respected and looked up to by men and women alike? Are you? You CAN be It’s EASY My amazing discovery of the workings of Natural Forces makes gaining of glorious health and physical strength EASY—and as natural as breathing. By my methods, YOU can acquire perfect Health, Lion-like Strength, and com- a lling Personal Power. I can help you as I have co ped thousands. I will put you on the high vad to MASTERFUL Achievement. I will put oe punch and power in you that will enable you to smash your way through to Success. I build men scientifically through STRONG- FORTISM, The Modern “er ice of Health and Strength. Results are stounding—almost mit cu lous. I have lifted thoueendeal men from the deep pit of failure and despair and shown them how to gain Health, Strength and Vitality. No matter if you are weak, ailing, nervous or the victim of some stubb rn chronic ailment, I can put you back in the game and give you the fire and energy of Physical P erfection, Startling Book FREE STRONGFORTISM—the that makes physical and mental super-men out of weaklings that makes business giants, social successes and leaders in trade and commerce out of weak, disease-racked, discouraged, hopeless men, is fully described in my new book, ‘‘Promotion and Conservation of Health, Strength and Mental Energy.’’ Let me send you a copy of this F RE I book, beautifully illustrated from living figures — ed with startli facts. Fill out the Free I ition Coupon and send to me TODAY with ‘ten cents (one dime) to cover mailing cost. LIONEL STRONGFORT Physical and Health Specialist Dept. 1360 Newark, New Jersey em ee nee eee ee ee CONSULTATION COUPON—Absolutely Confidential Lionel Strongfort, — ~ ay Sa N. J. VI send me 3 rig § ag . Tenclose ten cents (one dime) "tox Ret Send me special information on subjects mark: a (x) below without Science Colds Despondency Catarrh Skin Disorders Too Fat Debility Too Thi orpid Liver Tc Muscular Development Stomach Trouble t Cl t Strength I ; Bz “i Blood Ruptur “create ness Lumbago Constipation Neuralgia i i ies na la eesti einainiemieee POPULAR SCIENCE MONTHLY peceanitimmcsines Edison, the Man (Continued from page habit of saying at such times. a short nap with his assistants. istic, I would say, sense of humor. —if a funny side happened to develop. Ludwig Boehm, from Bonn, Germany. the vacuum. Boehm retain it. the bulbs be t air could reach them. A “Brilliant Idea’’ Wasted with a merry twinkle in his eye. we ought to get a patent on that.” “And how,’ manded, out any air to use in the blowpipe?” “There you are,” feigned chagrin. show him some reason why it done. inventor nowadays.” the phonograph, afreerun of thelaboratory. He natured, the typical thrifty Scotchman. izing various substances tos fall on MacKenzie’s heavy, red beard. yet!” a wisp from the whiskers. Seotchman’s hair Served as a burned with a peculiar reddish glow. “And what would you expect, of the light, (Continued on page 141) table, roll his coat about them for a pillow and lie down to sleep for an hour or two. “A soft bed spoils a man,’ he had a He might have gone home to sleep, for he lived only a short distance from the laboratory, but it was characteristic of him, of his thoughtfulness and considera- tion for others, that he preferred to snatch Besides his enthusiasm, his energy, his inventive genius, Edison’s chief character- always has been his No work ever was too serious for him to see the funny side of it In the spring and summer of 1879, I re- member, the bulbs we were using in the lamp experiments were being made by an expert glass-blower Edison had dis- covered that the lamp filaments were more durable and the light more brilliant when filaments were inclosed in a high yas experimenting to find the best method of obtaining a com- plete vacuum and then sealing the bulb to One day some one suggested to Boehm in the — of Mr. Edison that taken up in a balloon to a height above the atmosphere where no “That’s a good idea,”’ said Mr. Edison “T think the practical Boehm de- “are you to seal the bulbs with- exclaimed Edison in ‘A man can’t advance a brilliant idea without somebody trying to can’t be There’s not much chance for an When I heard that Edison was bringing old Jep Bisbee from Michigan to fiddle for I was not at all aston- Mac- ished, for Edison always has been most loyal to his friends. Thus, J. V. Kenzie, the old Scotchman who had first taught Edison telegraphy, used to stay at Menlo Park for months at a time and had was good- happy-go-lucky—anything but He used to stroll about the laboratory or sit beside the stove telling excruciatingly funny stories in Scotch, German, and_ Irish dialects. One day when Mr. Edison was carbon- serve as a basis for lamp filaments, his eyes happened to “There’s something we haven’t tried he cried, and as he spoke he plucked “The Edison-MacKenzie” lamp, as Mr. Edison styled the bulb in which the old filament, boys,’ Mr. Edison asked us, pointing to the color “when we’ve used such fiery We vancement of inventions, of C onception,” — - -THIS F ORM- DON’T LOSE YOUR RIGHTS [| TO PATENT PROTECTION Before disclosing your invention to anyone send for blank form *‘EVIDENCE OF CON- CEPTION”’ to be signed and witnessed. A sample form together with printed instructions will show youjust how to work up your evi- dence and establish thesame before filing ap plication for patent. As registered patent at. torneys we represent hundreds of inventors a! over the United States and Canadainthead Our schedule of fees willbe found reasoni able, The form “Evidence sample, instructions relating to obtaining of patents and schedule of fees A se - upon reque st. Ask for them,—a post card will do. PATENTS AT ELT MARKS LANCASTER 274 Ouray Bldg. WASHINGTON, D. C. Originators of forms “‘Evidence of Conception.” 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 te $1.00. Send for free book “WHAT TO INVENT”’ containing Suggestions to Inventors as to In- ventions Needed. We invite manufacturers to address us regarding inventions they want. WORLD PROGRESS PUB. Co., INC. Room 202 Victor Bidg. Washington, D. 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Write for Sam- Be Duta , Maney Mak- Proposi American Products Co. %—i 238 American Building, Cincinnati, Ohio You've heard your oe . neighbor praise the Path- WAL er, the wonderful weekly ROS SS news on story Magazine with over half @ million subscribers. Unbiased digest of national and world affairs. Chock full ofjust the kind of read- ing you want. Fun, fashions, question box, books, health— entertainment and instruction forall. Exciting serial and short Sash Send 15c (coin or stamps) today for thio big $1 paper 13 Money back if not satisfied. Sample copies free. PATHFINDER, 591 Langdon Sta., Washington, D.C. POPULAR SCIENCE MONTHLY Edison, the Man (Continued from page 140 whiskers as those?” That Edison, famous for his industry and energy, should have possessed real affection for so carefree a man as the old Scotchman is not remarkable. To Mac- Kenzie he owed, in a way, a tremendous debt, for Edison’s first electricity came from the tutelage which the Scotchman had given him in teleg- raphy. Nor was it merely to personal friends that Mr. Edison displayed loyalty and kindness. To his employees he always was the most considerate of men. After I had been at Menlo Park for about a year I was attacked by malaria. We were busy at the time, and I made no mention of be- ing ill, but tried to fight off the illness while I worked. One day, though, Mr. Edison called me aside. “Francis,” he said, “I’ve noticed you haven’t been looking well of late. I think you ought to go to Asbury Park and stay three or four weeks. That ought to fix you up.” Not only did he relieve me from my duties at the laboratory for a month, but penses of my vacation at the seashore. The Inventor as an Organist The youngest of us was no more lively than Mr. Edison in his moments of laxation. He enjoyed nothing better than a good rousing song. Few people prob- ably know it, but in those days at Menlo Park, Mr. Edison was more than a fair performer on the organ. After our mid- night lunch at the laboratory he would stroll to the organ at the end of the long room, and soon our voices would be ring- ing out in the popular songs of the day to his accompaniment. Boehm, the glass- blower, sometimes could be coaxed to play the zither and sing quaint German songs. One of the laboratory boys was an excellent mimic. He had an imitation of the original Edison phonograph, with the tinfoil records, which never failed to elicit peals of laughter from Mr. Edison. Sometimes Hussy, postmaster of Menlo Park, or Davis, the innkeeper, would join us at these midnight revels. One night Hussy, who sometimes might exaggerate a wee bit, began to tell his life history. Incident followed incident, but the rator showed no signs of weariness nor of reaching the end of his story. Mr. Edi- son, who was somewhat deaf even then, sat by, apparently paying no attention to the speaker. Suddenly, though, he out a piece of paper, scratched some figures on it, and then looking up, said: ‘‘Hussy, how long are you going to keep nar- took on working? Up to now I’ve figured that you’ve been working more than 150 years! Isn’t it about time you took a vacation?”’ This was said in an even tone, appar- ently with perfect good humor, yet we who knew him best saw that Mr. Edison was vexed by the old postmaster’s lengthy autobiography. For he always resented being imposed upon or having his credulity taxed even in small things. Mr. Edison’s self-confidence was su- (Continued on page 142) introduction to | he gave me the money to pay the ex- Wins a Welcome You are welcome everywhere with a sweet- toned Buescher Saxophone. It is an in- fallible key to social popularity. 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Edison, the Man (Continued from page 141) perb. The present generation, accus- tomed all its life to obtaining light by the simple act of pressing a button, probably will have difficulty in imagining the ridi- cule and criticism that met Edison’s efforts to develop the ancestor of the electric lamps that light our homes. It is even more difficult to believe that some of the foremost scientists of the time went so far as to call Edison, in effect, an ignorant and deluded man. But criticism, no matter how bitter, bothered him not at all. He was certain that eventually he would solve the problem of producing the incandescent light, and his faith in hime self made him impervious to the attacks of his critics. Typical of the criticism of Edison by the scientists of those days was that of Sylvanus P. Thomson, a great English electrician, who spoke of Edison’s “airy and made the positive state- any system of lighting de- pendent upon incandescence would fail. Not only that, but he proved it to the satisfaction of many! Unmoved by Critics’ Attacks W. H. Preece, electrician to the British Post Office Department, one of the great- est English electricians, and a pioneer in wireless telegraphy, pledged his reputa- tion to the assertion that Edison’s idea was a ‘‘mere chimera’? and was doomed to ignominious failure. Mr. Edison likes to remember that Preece later became one of his warmest friends and staunchest admirers. Other scientists declared it absurd that a man like Edison, who was ‘not even a mathematician,” should pre- sume to set himself to the solution of prob- lems that had baffled learned scientists. None of these attacks, however, ever brought from Edison a reply or a counter- charge. Reporters from the New York, Philadelphia, and Boston newspapers were besieging the Menlo Park laboratory constantly, laying the latest charges of his critics before Mr. Edison and seeking to arouse him into making a sensational statement in reply. Usually he warded off the questions of his visitors diplomatic- ally. Sometimes he became a little im- patient. One day he said: “I’m not working at the electric light for the sake of making a public exhibition of it, nor for the sake of announcing each step I take. I am working for a company, the Edison Electric [luminating Com- pany, and my only business is to supply that company with a perfect system of electric lighting.” ignorance,” ment that

He knew he would be successful, and he knew as well that his success would be the most formidable answer to his critics. Not that he was entirely careless of criticism. On the contrary, to read every line printed about him and | his work. It supplied him, I believe, with | a spur, driving him on to increased efforts. | Whenever any of us would come across a particularly savage attack, Mr. Edison would read it; then he would smile and say, ‘‘Never mind, boys. They’ll not only be reading by incandescent lamps soon, (Continued on page 143) } } | | } he was eager

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jenanacee rs! pes more 5 times eed No ex- deliver mu eve;ry are time. erms and 1, Ohio g show ing.—A % quickly RySLeTI. ch you 21106 NO e. T. 3-B F a. # Edison, the Man (Continued from page 142) _ but they’ll be running their elevators and sewing machines, and cooking their meals | by electricity, too!” I never saw Mr. Edison discouraged— not even in the days when, after experi- | menting with platinum lamps, he gave | them up and sought again to develop a carbon filament. At that time people were fond of comparing the incandescent lamp with the Keeley motor. Mr. Samuel Insull, now head of the power industries of the Middle West, who once was Edi- son’s secretary, however, tells of one time when the inventor became pessimistic. “Sammy,” Mr. Insull says Edison asked him one day, “do you think you can earn a living again as a stenographer? Because, if you do, I think I can earn my living as a telegraph operator. That will make us certain of having something to | eat anyway.” | That was in 1883 when Edison had started a lamp factory and the whole future of the Edison light system de- pended on its success. And it was a matter of financing a giant project, not of developing an invention, that had brought doubt of success to Edison’s mind. Lack- ing sufficient capital, Edison nevertheless | had plunged into the business of manu- | facture, because he aione possessed suffi- | cient faith in the future of electric lighting ;to do so. Though it was costing him | between one dollar and one dollar and | fifty cents to manufacture each lamp, he | had taken a contract to sell lamps at 40 | cents apiece! Scant wonder that he saw visions of starting all over again as a | telegrapher in order to live! Edison’s Critics Silenced He and Insull, though, attacked their apparently hopeless task with courage and determination. They pored over accounts and managed to meet the payroll somehow until Edison had placed his factory on a sound economic basis. At last the tide turned. The public woke up to the fact one day that the Edison factory was actually paying dividends. Edison’s critics were silenced! Problems equally difficult confronted Edison while erecting the first permanent commercial central electric-light station in the world in Pearl Street, New York City. Here again his indomitable perse- verance overcame apparently insurmount- able obstacles. Mr. John W. Lieb, now rice president of the New York Edison Company, was the first electrician of the Pearl Street station and participated in those stirring events. While Edison was establishing these | stations, there were times when all of us at the laboratory worked 36 or 48 hours at a streteh—sometimes longer. For the revolutionary undertaking necessitated the development of many inventions. |The electric transmission line of those days was a single circuit, supplying cur- Tent to are lamps connected in series, which meant that when one lamp got out of order every lamp in the circuit went dark. Yet even at the height of the work, (Continued on page 144) POPULAR SCIENCE MONTHLY 143 DIRECT to you from our Factory Big Saving in Price Yes, we will iin you this Genuine Underwood Rebuilt in our own factory just like new for ONLY $3 down—NOT ONE CENT More Until you have tried the machine 10 full days at our expense Write Right Now and learn how it is possible for us to ship you this Underwood Type- writer upon our free trial plan and our direct-to-you money. saving methods. Get the full de- tails now—just sign the coupon and mail today. Get all the facts > then decide. No Obligation —to buy. You don’t have to order. 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hat | Learned About Old Age Byram C. od A.M., L.L.D. t+ RTAIN facts about old age, recently dis- closed to me, consti- tute the most start- ling information I have ever received. I am 40 years old my- self. I had begun to wonder if I would soon begin to “break” —to lose my old-time pep and aggre ssive- my stamina and resistance to disease. I wondered if 1 would soon be subject to the class of ailments which seems so prev- alent among men past 40. Then through a mutual friend, I made the acquaintance of a member of the American Associa- new

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I have learned that 65° _ Ol all men a— a certain middk age have a dis ord ro little gland, called the prostate. And aoe tate disorder is not only the direct cause of much distress, often necessitating oper- ation, but it ‘lisplays itself in many parts of the bods mental as well as physical. Common Middle od Ailments Here is an im int iu il 3 which heretof.ce have been oe fa for ranted ld sree a: Brees scdek in back, le ind feet, frequent nightly risings nervousness and irrité ibility and frequent dizzy spells indicatir igh blood pre Ire; ind | learned how, by a istonishingly simple new method, that these disorders would be eliminated in many instance in a short time, without drugs or operation—a treatment that reaches this glanc directly —yet convenient that any can apply it I 10, 000 Men Find Relief But most ing ; find that 10,000 men have iL ready found relief. Statesme bankers, law t tor ever! sector or the ¢ intry are using and g th method. I read many let- ters. One was trom a man in Colorado. 73 year S my age,” | wro et for years I suffered w { tate trouble Used medicine to no 73 Year Young avail—had p hope when commended yur t t- ment.”” Just in 73 ye ld being restored | 1 and buovan t youth! And it is within the reach of ever Phe are no drug b ] All Explained i in FREE Book If y< ure é with any dis mention 1, if you have tipatior prostate trouble, you s l 1 for a vitally interesting free book, written by tl scientist, called “Why M vy Men Are Old at 40.""— It de- scribes this splendid treatment and shows how you m regain mu thful vigor and be free from certait di yt “ ; obligation, But write at « tl nited. Simply Daiigiilicieb Wieeaneh Commun, Steubenville, Ohio, the concern s for the author, mail request t¢« 4030 Main St., that is distributing these book

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Edison, the Man (Continued from page 143) Edison never was too busy to see any one who sought him out in his isolated New Jersey retreat to discuss an invention or some other ambitious undertaking. His own experience had taught him the value of encouragement to a pioneer. His own progressiveness caused him to be eager to foster progress in any direction. His kind- liness made him always willing to help others. Early in 1879 Lieut. G. W. DeLong, of the United States Navy, who was making preparations for a voyage of arctic ex- ploration, came several times to Menlo Park. Edison became so much interested in his plans that he designed a small dy- namo, some incandescent lamps and an are lamp for his ship, the Jeanette, which was being refitted for the expedition by James Gordon Bennett. Since the ship had no steam engine that could be used for the purpose, Mr. Edison designed the little dynamo to be operated by man power—in shifts of two men. “The boys ought to keep warm up in the arctic, turning that,’’ he observed to Lieutenant DeLong when he showed him the dynamo. A Visit from Sarah Bernhardt All of us who worked in the laboratory wrote our names on the paper insulation that was wound on the armature. And somewhere beneath the arctic seas names have lain for almost half a century, for the Jeanette never returned. Distinguished visitors almost without number found their way to the Edison laboratory even in those early days, for, although scientists were skeptical about the success of the incandescent lamp, Mr. Edison had won fame with other inven- tions, principally—so far as the public was concerned—the phonograph. Sarah Bernhardt was one of the visitors of 1880. We were accustomed to seeing Mr. Edison reserved, shy, even, in the presence of strangers. There was little shyness in his manner, though, as he ex- plained the workings of the phonograph that day, a fact which requires no explain- ing to anyone who ever has seen the Divine Sarah swaying vast audiences in the theater. time, the voice of an _ internationally famous artist was recorded on the talking machine. Madame Bernhardt was transported with amazement when she heard her own incomparable voice and accents repro- duced by the record. “C’est grand! siasm. I cannot believe that any of his achievements than the great ¥rench actress bestowed upon him that day. Moreover, was that day! our | C'est grand!”’ she ex- claimed again and again in frantic enthu- Thomas Edison ever received more rapturous praise for I am quite sure that no words he ever heard pleased him more. Since then the world has worn a path to his door, but never in its journeys to the doors of the great has the world numbered among its pathfinders any one more gra- | clous or more charming than Bernhardt

And that day, for the first

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ily DO ing ice iT me. it al. N ticu- aaa _—— and BOUT D FORD bullet Nose Choice of ors. Send lete Catalog Bodies, Ac- and Speed quipment. m factory. POPULAR SCIENCE MONTHLY 500°, AGE ENT PROFIT Genuine Gold Leaf Letters GUARANTEED TO NEVER TARNISH For store fronts, office windows, Bank windows, Office Doors, Panels, Board Signs, Trucks, Auto- mobiles and = Glass Signs of all kinds Anyone can put them on and make money right from the start without previous ex- All you have to do is to show the letters are very attrac- Letters costing sell for 25c. One agent says: ‘Your Letter are the best thing I have seen in years: I have made $125.00 the first week and still going strong.’"’ Paul Clark says: ‘Smallest day $28.70."" H. Gilder made $835.00 in six weeks. $60 to $200a Week GENERAL AGENTS— It is easy to appoint sub-agents for this line. We pay you 20% perience. your samples; tive and easy to sell. 31K cash commission on all orders we receive from local agents appointed by you anywhere. We allow you 50% discount your own orders. You can sell to nearby trade or travel all over the country, as you please Large demand for window lettering everywhere. Write today for free sample, full particulars and liberal offer to general agents. Metallic Letter Co., 433-AN. Clark St., Chicago on biphi, Ind. 5 SQUARES IN 4 TOOL TRY, MITER, OCTAGON, all in one handsome Blade locks instantly and automatically a at ANY ANGLE desired. Conve- m nient, accurate, a time-saver. # Always ready. Strong, du- rable, simple. If you use a saw you need this SIMORE “Lightning Change” ee With 41% or 6 incl h ble ide $3.75 With 7 % inch blade, postpaid $3.90 Mo: ey order or your check acceptable. Your money back if not satisfied. BEVEL and PRO- TRACTOR Square tool, Dealers are invited to write for our aeopenvon this and other Simore “‘Lightning-cha1 tools. The Combination knife and screwdriver ‘is a sure |} seuer, THE SIMON & SKIDMORE MFG. CO. Dept. 5-2 Santa Ana, Calif. “DON’T SHOUT” “T hear you. I can hear now as well as anybody. ‘HOW?’ With THE MORLEY PHONE. I've a pair in my ears now, but they are invisible. I would not know Ihadthem in, myself, only that I hear all right.” The Morley Phone for the DEAF is to the ears what glasses are to the eyes Invisible, comfortable, weight Anyone can adjust it. Over one hundred thou- loss and h cand roe armless, Write for booklet and testimonials, Dhitadainht Senses and Common Sense (Continued from page 38) Ninety-nine men in a hundred, feeling a piece of cloth, and receiving just as many touch impressions from its temperature, texture, roughness or smoothness, would pay no attention to them, just as they probably would fail to observe whether the dials of their watches contained Arabie or Roman numerals. And those 99 men would remain in the crowded ranks of poorly paid routine workers, while the hundredth man became a textile expert at a high salary. I have seen expert machinists gaging the thickness of metal pieces almost as accurately as with a micrometer by feeling them. Others achieve the same degree of accuracy with their eyes. Especially gifted men? Not at all. Merely men who have learned the habits of attention and of interpreting their sensations correctly. At the beginning their jobs depended on this faculty, and in time the habit of attention, instead of being irksome, became com- paratively easy. If you drive an automobile in one frequently, you probably learned to judge speed and distance. Cer- tainly you can distinguish between a speed of 25 miles an hour and 30 miles an hour without consulting the speedometer. A few years ago you could not do this. The faculty has come to you because you have trained your sense of sight uncon- sciously while motoring. or ride have Senses Improve with Use This illustrates vividly an important consideration—that the improve with use. Moreover, the consciousness of possessing senses that are trained and so can be depended on to transmit accur- ately to the brain the impressions they re- ceive, brings the self-confidence that is certain to lead on to greater achievements, Through the senses we obtain knowledge, and knowledge is power. The carpenter reaches into his chest and without looking draws out the tool he wishes to use. Training of his sense of touch has taught him to differentiate un- erringly between the feel of the handle of a chisel or some other To a layman the ledger of a commercial enterprise seems merely an unfathomable jumble of figures. To an accountant’s trained eye, though, it tells a vivid story of the state of the concern’s health. I might multiply examples of the sort without number—ordinary persons who excel their fellows by no natural equip- ment of talent, but who have acquired a high degree of useful skill simply through senses tool. business practice and the use of their senses. Typists, linotype operators, printers, musicians, draftsmen, artists, lawyers, surgeons, dentists, writers, workers in many fields of science—all these win suc- cess in the degree to which they develop one or more of the senses. Touch, eyesight, and hearing probably are the senses most generally employed in the more familiar forms of human deavor. But even the sense of smell, so little developed in the ordinary man and regarded by him as extremely unimpor- (Continued on page 146) en- THE MORLEY CO., Dept. 797, 10S. 18th Street, ? HIGH SCHOOL COURSE IN TWO YEARS YOU ARE BADLY if you tack HANDICAPPED High School 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 Thiscourse, 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 ftdle 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 a Dept. H275 P Drexel Ave. and 58th St., Chicago)# American School Dept. H275 Drexel Ave. & 58th St.; Chicago Send me full information on the subject checked and how you will help me win success, ...... Architect .. Building Contractor ....Automobile Engineer ...Automobile Repairman Civil Engineer .. Structural Engineer Business Manager Cert. Public Accountant ....-Accountant and Auditor ..... Bookkee per ..Draftsman and Designer Electrical Engineer Electric Light & Power ...General Education Vocational Guidance ae Lawyer ......-Machine Shop Practice Photoplay Writer ....Mechanical Engineer .. Shop Superintendent ..Employment Manager Steam Engineer Foremanship .emanitary Engineer ... Surveyor (& Mapping? Telephone Engineer Telegraph Engineer High School Graduate Fire Insurance Expert Wireless Radio --Business Law nna Undecided ea CO A PEN PO OEE ELA eee —_ Address eccceeccscervann-b

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148 146 Drawn from actual photograph of student doing ha time electrical work tricity Make Bis Moncy How would you like to earn two or three dollars every evening after school and pre- are yourself for a fine big job at the same _ time? iere’s the opportunity of a lifetime for you fellows who like Electricity. Begin right now to prepare yourself for a regular man’s size job in this fascinat- ing field. Your chances for a big success are simply wonderful—the pay is big ($70 to $200 a week) and advancement comes swift and sure. K will Train You at Home With my easily learned, sparetime Electrical Course I will train you at home like I havetrained hundreds of other boys who are now big successful men. It will not inter- Loo fere with your school work and k What you canearnmorethanthesmall | This Boy cost of the course doing odd elec- Is Doing trical jobs in your spare time.The Course pays foritself. I will show you ino toget this work and how to doit. Some of my boy students make $10 to $15 a week this way. Tools, Apparatus and RadioCourse FREE Send me the coupon below andI will tell you all about the big out- fit of tools, apparatus and instru- ments and a new Radio Course that Iam giving to my students for alimited time. I willsend you my big interesting Electrical Book and a sample lesson, too— all Free. You will be tickled with the things I willsend you Free. Mail the coupon right now. L. L. COOKE, Chief Engineer Chicago Engineering Works “Although the School term {is com- ing to a close, and I am pretty busy with my examinations, I manage to keep up with my electrical studies and work. “I guess I forgot to tell you lam now {n business for my- self. Am doing fine, but owe it all to you. If it had not been for your Course, I, being under age. could not have secured my li- cense in this town. But I got it, and now have all the work I cando,averaging $20 to $30 a week, thru spare time work. ‘I went out on a job tonight after school, on which I made $3 and bro rought ome another on whic th I made $2.50— $5.50, for 4 hours’ work and no material furnished by me. ROGER SMITH, 1216 Chestnut St., Greenville, N.C” Dept. 532 CHICAGO Use This “FREE OUTFIT” Coupon L. L. COOKE, Chief Engineer, Chicago Engineering Works, Dept. 532, 2150 Lawrence Ave., Chicago Send me your Free Outfit Offer, your big Electrical Book, Sample Lesson and particulars of your Electrical Course and Free Radio Course, This will not obligate me in any way. Dea ichian a iestiiniis le otieoiasneitcbi Address. Planning a NEW HOME? Let these Books be your Guide. Beautiful Cali fornia Styles, with Pic tures and Plans for all- climate homes. “All. American Homes’. > 10 SPECIAL OFFER: Send $2.50 for any three Books and Ga- rage Folder. y back if not satisfied. 7% Spz Anish. English ,some 2fa amily, $1 **The New Colonials'’ Roo ms—$1 alows’’ Rooms—$1 **Little Bungalows"’ Mone Houses—3, 4 and 6 Rooms—$1 E. W. STILLWELL & CO., Architects, 110 Calif. Bldg., Los Angeles 60 Haaeas 6 to 10 West Coast Bun: 50 Houses—6 and 7 POPULAR SCIENCE MONTHLY Senses and Common Sense (Continued from page 145) tant so far as practical life is concerned, is used by many persons with such nice powers of discrimination that they not only make a good living, but often repre- sent a vital link in the affairs of important industries. Tea tasters and testers of tobacco, foods, perfume, and beverages are only a few of those who utilize their trained sense of smell for their own benefit and the benefit of mankind. But, you may say, how does all this apply to me? taster; it is not necessary for me to be able to estimate the thickness of materials by my sense of touch. Ihaveajob. My work is all cut out for me. Are you satisfied with that job? Don’t you want to advance beyond it? There is no surer way for you to win promotion than by sharpening your senses through exercise. If you are an office worker, for exam- ple, your sense of sight, your sense of hearing, several of your senses of touch are called into play. If you are a sales- man, the same senses are used by you, with greater rapidity, because your work is less of a routine nature and you are constantly confronted with the necessity of solving new problems. If you are a manual worker, your senses of touch and sight are your bulwarks. Conscious Use Trains the Senses Learn to use these senses consciously. If you are looking at a thing, don’t satisfied to let that thing merely happen across your vision like a flash “of light. See not only the thing itself—its size, shape, and color—but perceive and record the things surrounding it and their rela- tion to the principal object. Hear things, smell things, touch things, taste things in the same manner. Muster every you can in obtaining your impressions of an object, whether it is a column of figures in a ledger, a bolt of cloth of a new pattern, a blueprint draw- ing, a letter. Sense it in terms of other things with which you already are famil- iar. That is how the textile expert gages the value of materials, how the physician diagnoses the illness of his patient, the machinist estimates the size of ma- terials. Learn to concentrate. These few words are the key that will unlock the wonderful storehouse of hidden powers in your mind. If you will concentrate—on your plea- and hobbies well on your your senses will train themselves. Your eyes are eager to see, your ears to hear, your other 25 or more—to perform their functions. They will develop if you will give them free rein by cultivating the habit of attention, a thing which because it offers so many advan- tages and much profit to you, you should be prompted to do through the ex- ercise of that greatest sense of all—com- mon sense. be sense sures as as tasks senses SO In next month’s article Doctor Walsh will tell why we are what our habits make us, and how we can make and break our habits. POPT)].AR SCIFNCK VWUONTUIV I have no wish to be a tea | | direct and your order will be promptly filled, but they must record their impressions | how | i ee PLUG-JACKL a pair of | 4 $F] O° MURDOCK Fae HEAD P re 6 best in C.) raato AT ALL RADIO DEALERS If your dealer cannot supply you send money WM. J. MURDOCK COMPANY 345 Washington Ave., Chelsea, Mas Woe have positions open now that will pay from $45 to $100 a week. We aro organizing a sales force to introduce the Cole Visible Gasoline Gauge, a low-priced, scientifically accurate strument for Ford and Chevrolet cars. Prevents running out of gas. Guards against short measure. Fits on instrument board—always in sight. Big selling records ule VE ‘ be MAKE $50 THE FIRST WEEK We want one man in each coun- ine fauge/ . ay ty. Our campaign is just beg Capital is not necessary. We help you start. Ter- ritory going fast. Write to THE STEMCO ENGI- NEERING CO., 118 Webb St., Dayton, 0. RN MONE’ EA AT ome you can make $15 to $60 weekly in your spare time writing show cards. No canvassing or soliciting, We instruct you by our new simple Directograph System, supply you with work and pay you cash each week. ‘rite today for full particulars and free booklet. WEST-ANGUS SHOW CARD SERVICE LIMITED Authorized Capital $1,250,000.00 63 Colborne Building, Toronto, Can. DON’T WEAR A TRUSS BE COMFORTABLE— Wear the Brooks. Appliance, the modern scientific invention whic fis es gy sufferers immediate re= ief. It has no obnoxious springs or pads. Automatie Air Cushions bind and oe re pearend ai aie ay arts. o salves or plasters. Durable eap. Sent on trial to prove its worth. Bee MR. C. E. BROOKS ware of imitations. Look for trade-mark bearing portrait Pat “9-913; $-1-17; ning. ™ 7-16-18: 10-19-20. the anc bou om: ven obs the som and the and signature of C. E. Brooks which appears on every Appliance, None other genuine, Full information ard booklet sent free in plain, sealed envelope, BROOKS APPLIANCE CO., 230 State St., Marshall, Mich “LIGHTING FIXTURES” Ready to hang. Direct from manufacturers Completely wired including glassware. Send for Catalogue No. 24 and Dealers’ proposition. ERIE FIXTURE SUPPLY CO. Desk A, Erie, Pa. und “

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RS | money ly filled. PANY, , Mas that will We are introduce Gauge, 2 rate olet cars. Guards nstrument g rect rds. ST WEEK sach coun- ust begin- necessary. art. Ter- . Write to ) ENGI- co., Dayton, 0. ur spare nvaseing 0.00 ES 4 ive 3 . E. BROOKS ring portrait -ars on every ormation ar arshall, Mich icturers d including No. 24 and sition. JPPLY CO. , Pa. URES” | | mense distances of the universe. Astronomy from the Cellar (Continued from page 41) give us no clear perception of the im- Even to say that the sun is 93,000,000 miles away from us cannot convey a definite impression to the inhabitants of a planet only about 8000 miles in diameter, to whom an airplane journey of 3000 miles in a little more than a day seems almost incredible. “How can we comprehend, then, that some of the stars of the Milky Way are more than one hundred thousand trillion miles away from us? Write this number on a piece of paper—100,000 followed by 12 ciphers—then try to picture the dis- tance in terms of any earthly measure- ment, such as the breadth of the Atlantic Ocean. Of course, this gives you no com- prehensible picture, but don’t let that dis- courage you. Astronomers have been trying unsuccessfully for centuries to comprehend the awful distances of space. Even using the light year—an astronomi- cal unit equivalent to about six million million miles—they are unable to picture understandably the sublime abysses of the worlds beyond. “Astronomy has been my hobby for many years. I have pursued it unceas- ingly and with ever-increasing enthusi- asm. There was a time when I believed there was no room in my life for anything but my work. I had taught myself to work constantly, every hour of the day. “And then I made the important dis- covery that, commendable and important though industry may be, a man must have some other interest beyond his work. The Telescope Opened His Eyes “T took up yachting, and for several seasons it served its purpose of taking my mind from my business eares. Then, returning from a business trip to Europe one summer, I was unpleasantly shocked to find that my eyes no longer were able to pick up distant objects at sea as‘they formerly had been. Astronomers and others frequently had described to me the wonders of the heavens, and I decided then that if ever I was to see those won- ders it was time to start. So when I landed in New York I bought a telescope. “That instrument opened my eyes to the marvelous sights the heavens offered, and before I knew it I was unescapably bound to the fascinating study of astron- omy. However, there were certain incon- veniences connected with astronomical observation as I was conducting it. In the warm weather mosquitoes made it a somewhat heroic undertaking. In the fall and winter the cold winds chilled me to the bones. For self protection I built my underground observatory. “In designing my observatory I was helped rather than hampered by my lack of technical knowledge of approved methods. I produced an observatory that suited my purpose, even though ex- perts told me my methods were wrong. The observation chamber and the tunnel connecting it with my home were the first units completed. The tunnel carries water and heating pipes and electric wires (Continued on page 148) POPULAR SCIENCE MONTHLY ‘The hook~ 147 Fee ee tetas ae tg nr ape wee hag * up that~ eliminates battery trouble Some radio fans are still slaves to their batteries—lug them to service stations every time they need recharging—allow them to spoil many evenings’ entertainment by*running low. Other fans—and they’re quickly coming to be the vast majority have found new economy and convenience in the GOLD SEAL HOMCHARGER, the world’s best as well as its most popular rectifier. for a nickel. With it any radio or auto battery can be charged at home overnight Simple, dependable, practically silent and absolutely safe. Beautifully finished in mahogany and gold. Approved by Underwriters. UNQUALIFIEDLY GUAR- ANTEED. Over 150,000 now in use. WHY PAY MORE—OR GET LESS? Why buy a 2 or 3 ampere rectifier without ammeter requiring from 40 to 50 hours to charge your battery and costing twice as much to operate when, for the same price you can secure the genuine 5-ampere GOLD SEAL HOMCHARGER which does Insist on the GOLD SEAL Accept no substitute plate and carton before pure hasing No other charger is just as good on seeing our registered trade mark, the GOLD SEAL, on name a better job in one-third the time and at half the cost. Fitted with high grade ammeter (eliminating guesswork) charging cable and battery clips—no extras to buy. by all good dealers—$18.50. For sale Insist RADIO FANS—ATTENTION! FREE atc station in the world. Ask your dealer for a free copy of the HOMCHARGER international list of broadcasting Contains call letters, location, name and wave length of nearly every broad« asting DEALERS—JOBBERS! Prepa re for the big HOMCHARGER year ahead by writing today fora copy of our elaborate mer« handising plans In it is illustrated many attractive sales helps that will enable you to get your share of this business. Che Automatic Electrical DevicesCo., 131 West Third St., Cincinnati, 0. ex Largest Manufacturers of Vibrating Rectifiers in the World» GOLD SEAL HOMCHARGER Stop Using a Truss STUART'S PLAPAO- PADS are different from the truss, being mechanico chemico applicators made self-adhesive purposely to hold the distended muscles securely in place. No straps, buckles or spring attached cannot slip, so cannot chafe or press against the pubic bone. Thous — ive successfully treated them Reduced = celves at home without _ Reduced Fac-Simile hindrance from work—most Fae-Simile Gold Medal ohstinate cases conquered Grand Prix Soft as velvet—easy to apply—inexpensive. Awarded Gold Medal and Grand Prix Process of recovery is natural, so afterwards no further use for eben ee We prove it by sending Trial of Plapao absolutely Write name on Coupon and send TODAY: FREE Plapao Co., 790 Stuart Bldg., St. Louis, Mo. TTT ST ST Tere Te TTT TTP ET Te —$—$_—— LE This set has beautiful solid mahogany, wax finished cabinet and greatly adds to the appear ance of any home Consists ot a regenerative tuner, detector and two stages of amplification, with built in loud speaker rhe tuning circuit is licensed under the Armstrong | Patent No. 1,113,149 and due to th particular method of winding Crosley coils it is exceptionally selective ifficient room inside cabinet for dry batteries, making a complet If-contained long range receiving out fit. Has phone jack for tuning with head phones Crosley multistat; filament vitch Crosl moulded condenser, beautifully engraved formica panel. Uses all kinds of tubes Price $125. Prices do not include batteries or tubs If your dealer cannot supp! ou order direct mentioning his name THE PRECISION EQUIPMENT CO. Powel Crosley, Jr., Pres 217 Vandalia Ave. Cincinnati, Ohio

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148 POPULAR SCIENCE MONTHLY

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Nearly every man wants a gun in the house—he feels better able to protect his family. We are able to offer these Genuine Astra guns at special prices because we bought before recent tariff raises became effective. Really fine finished, hard hitting. Use standard < direct from U. S. importers. guns, beautifully ammunition. Order alibre—7 shot—C . 25 ¢ . 0. Q. Automatic. 8.95 25 calibre—7 shot—Astra Automatic, 9.96 25 calibre Astra with triple safety. 10.35 32 c alibre—10 shot Astra, extra magazine. 16.95 32-20 and 38 cal. swing-out cyl. revolvers. We guarantee every gun against defective work- manship; brand new; of Drop Forged Steel Through- eut. Before buyisg any weapon INSIST on this guarantee. SEND NO MONEY unless you wish. State model desired—pay postman on delivery lus postage. Satisfaction guaranteed or money re- ‘unded. Write for new firearms catalogue. CALIFORNIA TRADING CO. Dept. 12. Terminal Bidg., Los Angeles, Cal. CRE =

Astronomy from the Cellar 147) to the observatory, and also provides protected passageway. (Continued from page a “T have added to the observatory from | time to time, until now I have a complete underground bungalow. out and the size of the chambers, by the way, bear quite a striking similarity to th | tomb of Tut-Ankh-Amen. “Of course, having become tremen dously interested in astronomy myself, would like every one else to share my in terest. It is most gratifying to me to know that 18 young men in Springfield have built their own telescopes, which they carry up the mountains to pursue astronomical observation. “Tf people only knew the thrill and | stimulation of a telescopic journey into other worlds, I am sure that when building their homes they would open a window to the sky before opening one to the street. | | Why have a window through which you can see only a dog fight or a few persons | passing along the street when you might

| have one that will show you the vast depths of space and the stars and planets that lie there? There is no special back- ground of education needed to undertake an intelligent study of astronomy in a human way; merely a capacity to appre- ciate and to make comparisons between things of tremendous magnitude and | things that matter little. “T was talking of astronomy to a young man whom I met on a train recently. | tried to make clear to him its wonderful interest and its thrilling possibilities, even foralayman. He listened tome, thensaid: Schoolbook Astronomy Fooled Him ‘Well, if that’s astronomy, they fooled me badly when I was studying it in school! My book on astronomy had a lot of funny diagrams, and hazy pictures of stars with | long names and some problems in spheri-

cal trigonometry. I hated it!’ ‘‘Many schools approach the teaching The general lay- |

of astronomy from the wrong direction. | Looking at a picture of a star bears about the same relation to seeing the star itself through a telescope as looking at a friend’s picture bears to having the friend beside you, talking to you. See here.”’ Mr. Hartness turned an electric switch | and immediately on the four walls of his study appeared four life-size pictures—a young woman, alittle girl, an elderly man, | and President Coolidge and his family. | Mr. Hartness smiled and pointed to an odd instrument that stood beside his desk ‘‘A projector,” he explained. ‘I find that by projecting the pictures of my family and friends in life size on the walls they are brought nearer to me than if | merely had their photographs framed and hung there. That illustrates in a way what I mean by the difference betwee | seeing a star and seeing a picture of one. “One of the valuable lessons we can take from astronomy is the necessity of staying on the job. Our earth and all the greater and millions of years. well might follow!’’

and lesser bodies beyond have _been traveling unceasingly and unfail- ingly through the same orbits for millions | They never falter in their course—an example that all of us | John |

| thir | fam | trat — rr prin | expl | Illus M Floy lead steir Gn Inve Illus Ci I. kK Univ Hou Es Alfre Su Theo Tran and | Cour Eli ter, \ | Co Meth AB: Socio Maer A and ( W.W the Ir nolog Gree; Fu revise A i? Hale R véeG

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i POPULAR SCIENCE MONTHLY 149 i Columbia

A resumé of new books on science and invention | Recent Publications | |

oe mets ; : euiv. | [| to iustrated. E. P. Dutton & Co. Binding Posts on Columbia Ignitor at no extra cost. to an | Conservatism, Radicalism and Scientific | desk. | | | Method, an essay in social attitudes, by | NATIONAL CARBON COMPANY, INC. F and} | A. B. Wolfe, professor of Economies and | New York San Francisco of my | Sociology, University of Ohio. The | CANADIAN NATIONAL CARBON CO.. Limited > walls | Macmillan Company. Factory and Offices: Toronto, Ontario in if | A Textbook of Physics (eighth edition) ed and | and General Physics (second edition), by | a way | | W. Watson, revised by Herbert Moss, of for tween | the Imperial College of Science and Tech- of one. nology, London. Illustrated. Longmans, —Motor boat ignition —Running toys es ms Green & Co. —Gas engine ignition —Telephone and telegraph sity 0 . : pee ree oe all | Furnace Heating, by William G. Snow, —Tractor ignition —Lighting tents and out- d have | Tevised and enlarged. U. P. C. Book Co. —Starting Fords buildings unfail- | America in Spitzbergen, by Nathan ne Sane dln edeeten nillions | || Hale Dole. Marshall Jones Company. —Buzzers —Heat regulators r falter | ; aly oe : —Ringing burglar alarms —Electric clocks aes. | Reactionism, The Science of You, by —Calli s —Radio / John D. Boyle. G. P. Putnam’s Sons. Calling Pullman porters adio A

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150 POPULAR SCIENCE MONTHLY ReduceTubesby Half With Erla Synchronizing Transformers

Tl=3 are Vacuum Yubes Vacuum Yubes inERLA Duo Ql 2 —_ as Ordinaril Reflex Circuits Employed — 3 ome , eae

Increased amplification and elimination of distortion inevitably follow installa- tion of Erla transformers. Reflex and cascade types. $5 Nation Wide Loud Speaker Reception With Only Three Tubes Greater range and volume with fewer tubes than ever before are attained through Erla Duo-Reflex circuits, using Erla synchronizing radio and audio transformers. In Erla circuits, tubes do triple duty, as simulta- neous amplifiers of received radio frequency, re- flexed radio frequency, and reflexed audio fre- quency currents. Through accurate superimpos- ition of currents identica! in phase and frequency, by means of Erla synchronizing transformers, this triple function is flawlessly performed, resulting in tremendously magnified amplication without distortion.

Erla audio transformers add tremendously to the purity and volume of any receiving unit in which they are used. Ratios 314 and 6to 1. $5 Even one tube provides excellent loud speaker reception over a wide range; two tubes blanket the zone ordinarily covered by four; while three tubes bring in stations on the loud speaker from coast to coast. Other notable improvements, contributing vitally to the superiority of Duo-Reflex circuits, are the Erla fixed crystal! rectifier and Erla tested capacity condensers. Combining advanced characteristics for reflex work with unduplicated uniformity, they are indispensable to complete stability and purity of reproduction. 16. er's name.

Crystal troubles vanish on installing an Erla_ rectif- er. No siiainat wianived. Proof against jolt and jar. Lasts indefinitely. List $1 Jobbers — Sweeping success of Erla circuits fosters con- tinually increasing demand or Erla products. rite for terms and discounts. Detailed diagrams and descriptions of Erla Duo- Reflex circuits are presented in Erla Bulletin No. Ask your dealer, or write, giving your deal- Electrical Research Laboratories Dept. F 2515 Michigan Avenue, Chicago L A

Motorcycle Bargains aaa a4, Bet SAVE 25% to 65% NAY, on Slightly Used and Rebuilt Harley-Davidson, Cleveland, Side , } Cars, Johnson Motor Wheels, Evans Power Cycles, Bicycles. Send for Free Bargain Bulletin an Money Saving Message, hundreds of bargains supplies, accessorie AMERIC “AN. MOTOR CYCLE CO 2047 W. Chicago Ave. CHICAGO listing hn used, rebuilt and new machines, Dept. 226

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MAKE BIG MONEY CHARGING BATTERIES Small casi Bom yack brings you MB 8 hour charging uttit. Easy terms of only $20 monthly et ‘your profits nice surplus besides. Thirty day free trial on money back guarantee lets you try HB outfit at our risk. You can easily make $150 to $300 monthly. Start now to make rofits with HB 8 hour -s weed charger. rite today for Bulletin 32 HOBART BROS. co. nce with Box P2 Troy, Ohio

~ j{ blood. As soon as blood gets out of its ‘proper channels in the veins and arteries,

Here Are Correct Answers to Questions on Page 53 | 1. Coal is impure carbon. Diamond is | pure carbon, crystallized. That is, dia- monds have their carbon atoms arranged in a definite form, rigidly fixed. 2. Because the blood clots. a material called fibrin, This is due to which is in the this fibrin begins to form a solid clot or curd. This clot stops up the holes where the blood vessels were cut.

3. Food keeps on cooking as long as it is | hot. The fireless cooker merely keeps it | hot by preventing the loss of heat. 4. No. Our system of writing music is | rather artificial. Out of the millions of | possible notes, musicians have selected | about 120. These selected notes make up the “scales.” The songs of birds often contain notes that are not in this arbitrary system, not because they are higher or lower, but because they fall in between two of our selected notes. 5. The air on the earth holds the heat in, much as the glass of a hothouse holds the heat inside it. On a mountain the air is thinner and does not hold the heatinso well. 6. No. The number of times he comes up, if at all, will depend on his strength, on the weight of his body, on whether the water is salt or fresh, on the currents, etc. 7. When you are tired, two or three lumps of sugar dissolvedina glass of hot water and drunk on an empty stomach make an ex- cellent stimulant. It is harmless except to those who cannot eat sugar. 8. It is the speed with which nerve mes- sages can be passed around inside the brain. This is very great. The speed of nerve impulses, you remember, is 404 feet a second. Suppose you think of an idea so complicated that it requires 100 succes- | sive nerve messages from one side of the | brain to another. Ali these 100 messages | can be carried and the thought can be completed in less than a tenth of a second.

. Because during millions of years the rains have been wearing down the land and carrying the dust and sand from it into the sea, and enough of it has accu- mulated to make the sea salty. 10. Compress it by a pump, like a tire | pump. Remember that heat is really the motion of the atoms vibrating back and forth. When you compress air, you push | its atoms closer together. This makes | them hit against each other more often | | and makes them vibrate faster. The record is made on a disk of soft wax. Thesound from the musician enters the horn and makes the needle vibrate. | This vibration causes the sharp point of the needle to make a series of tiny micro- scopic marks on the bottom of the wax groove in which it is running. These marks are an exact picture of the sound. When an ordinary hard record is made from this soft wax one, it contains these same marks. When you play it, your needle runs over these marks and they make it exactly reproduce the sound that made the marks on the wax. | 12. It is a mixture of two chemicals with oxygen that produces the light. One of the chemicals is used up in the process and perhaps both are. It has been impossible | | to duplicate these chemicals.

Page 127

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Page 128

26 MONTHLY You Are Wanted For a Better Job That was the good news they brought him just a few short months ago. Then, he held an ordinary job working long and hard on small pay. Today he is a, high salaried Draftsman earning nearly $100 a week. How did it happen? It isn’t a long story because it’s all so simple,— so easy. You can do just what he has done if you'll start by reading every word—clear down to the coupon that marks your way to better pay. It all started one evening while he was sitting at home— reading. He saw the advertisement of the COLUMBIA SCHOOL OF DRAFTING and he knew it was his op- portunity to earn from $50 to $100 a week, in an un- crowded field with a big, sure future. He sent in the coupon. Later he enrolled for the COLUMBIA course. loday he's making real money His brain is working, as well as his hands. He's standing on the threshold of a brilliant future with all that it means—independence money—success—happiness. MADE $275 } x TRS IN 3 DAYS He recently received $275 for one dri wing that he made in spare time in three days. HOW ABOUT YOU? Are you working up hill or down? Count the money in your pay envelope next pay day. You'll find the answer there. MAKE $50 to $100 A WEEK. vou to be an expert home by mail. now PROMOTION IS QUICK. WE'LL QUALIFY YOU for a high-salaried position in the Drafting field and keep you in touch with openings for Draftsmen in the big COLUMBIA will train Draftsman in your spare time at There's lots of room for you if you act machine shops, industrial plants and United States Gov- ernment departments. Men who start as Draftsmen are often advanced to Chief Draftsmen, Chief Engineers, Production Managers and so on. GET THE RIGHT TRAINING. Mr. Claflin, the founder and director tands personally in back of the COLUMBIA SCHOOL OF DRAFTING. Jou spend no time in long-winded theories—useless and expensive to you You start on actual drawing work the day you reccive your first lesson. YOU NEED NO PREVIOUS TRAINING. The course is easy to understand and easy to fellow Many students are qualified even before they complete the course. SUCCESS CALLS MEN OF ACTION ONLY If you are a man of action clip the coupon now and show that you are a man of action. Keep right on top of this oppor tunity to make real money. Don’t go looking for a pair of lear the coupon off and mail it right now. Get d now ---=- —FREE BOOK COUPON- = —— ~ [ cou MBIA SCHOOI OF DRAFTING Sts., N. W., | cissors start Dept. 2307, 14th | Washington, D. C and 1 Please send me without charge your free illustrated | book on Drafting, telling me how I can secure your 1 complete Home Study Course and your help in | | securing a position as Draftsman. We professional to keep when you complete with our cours Drafting outfit. It the give you Free, *, this is yours Course. WHAT WE GIVE YOU PRACTICAL PROBLEMS. You are carefully coached in practical Drafting work. WE HELP YOU GET A JOB. We help you get a position as a practical Draftsman, as soon as you are qualified. PERSONAL INSTRUCTION AND SUPERVISION THROUGHOUT THE COURSE. You receive the per- sonal instruction and help of Roy C. Claflin, President of the COLUMBIA SCHOOL OF DRAFTING and a practical Draftsman of many years’ experience. DRAFTSMAN’S EQUIPMENT. We furnish you witha full set of First Class Drawing Equipment and Drafting Instruments as shown in the picture below when you en- roll. You keep both sets on completing the course. CONSULTATION PRIVILEGES. You are free to write us at any time for advice and suggestions regarding your success. DIPLOMA. The diploma we give you on completing the course attests to your proficiency as a Draftsman. It is an ‘“‘entering wedge" to success. FREE SUBSCRIPTION TO DRAFTING PUBLICA- TION, “THE COMPASS." You are given free a sub- scription to our helpful, inspiring publication, ‘‘The Compass.” U. S. CIVIL SERVICE COMMISSION NEEDS DRAFTSMEN The following are a few of the many positions open in Government Departments from time to time. The salaries are starting salaries, subject to increase. Practical- ly all of them carry a bonus of $240 a year additional Architectural Designer, $4,000 Chief Draftsman Naval Aircraft Factory, $15.04 per day. Ae — autical Draftsman—Field Service of Navy Dept., $5.20 to $12 per day. Send in this coupon today. FREE BOOK Immediately on receipt of it we will send you our book, ‘‘Drafting—Your Success”’ which tells about Drafting and its opportunities for you as well as the special easy ntethod of learning Mechanical Drafting through COLUMBIA methods. THE COLUMBIA SCHOOL of DRAFTING Roy C. Claflin, President Dept. 2307, 14th & T Sts., N. W. Washington, D. C. Learn Music Make More Money Never before euch a demand for musicians as now. Not enough trained people to supply the positions open at theaters, clubs, hotels, amusement parks, orchestras and private entertainmentseverywhere. Big salaries waiting for those who can qualify. Learn to play an instrument and double or triple your earning power. Many musicians make as high as $200 weekly. Learn at Home—In Spare Time! By the University Extension method, you can quickly and easily master any instrument. Experte will teach you by mailin yourspare time. Nospecial talent or previous study required. Thousands suc- cessful through this training. Write and mention instrument preferred. Postcard bringsinformaticn. University Extension Conservatory 702 East 4ist Street, Dept.914 Chicago, Hl. 28 DETROIT SHOW CARD STUDIOS 807 Dinan Building, Detroit, Mich. Dear Sirs:—Without further obliga- tion please send me your FREE illus trated book giving full particulars how I can make $15 to $50 a week at Home in my SPARE TIME, WITHOUT CANVASSING. 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arly, oklet suild- ee 1 po- ry 1 any ir line > Grip ‘ourse, Sioux * store gents, Neil- lumbus oppor- ce un- stective Send utchung ir us af Penne I ouis, Mio ir Issues, latemala, ets 50% We buy np Com- ee America. u, Cuba, )0 hinres nan, 5949 Colorado ————$—— approval ». ¢ aaa f coins for coins, 10 Mass ae 1.50; 500 go. $$ applicants TT r approval ond Stree! -aiccaeeciainae Lists free ————— zo, Nyassi- to approv | ix, Arizona ~ 5 Mulberry, i 72c for & to approve 2 Atlanta, —— tamp Paper —- | applicants g Slaughter aa yroval. Rev ba ae 1.600, $1.5! — aa Browne, & ——— unities How to Discover and Correct POPULAR SCIENCE MONTHLY 2/ Your Weak Points What is holding you back? on all six. A Pelmanist is alive. and they all know that they can’t expect full, maximum power and speed from an engine that is “missing,” or choked with carbon. The moment a “knock” or a “‘pound” appears, they have it fixed. But thousands of these same Americans go around with their much more valuable brain- machinery groaning and creaking for lack of a little intelligent attention and care! They try to make the grade of success with the WILL-POWER cylinder not firing at all or with a sooty spark plug in the PURPOSE ylinder. Or may be they are not getting the help they could from CONCENTRATION, OBSERVATION, IMAGINATION, or MEMORY. And the worst of it is that they don’t know where the trouble is! They just go knocking” and “hammering” along through life, wondering why they can never catch up with any of the BIG rewards that always keep disappearing just ’round the turn of the road ahead. Only a “well-tuned” brains gets what it means Orn ten million Americans drive cars, Perhaps you have the idea that you lack WILL-POWER. So you set out to develop it. But, even if you succeed, it isn’t going to bring you the rewards you want—not all by You also need keen OBSERVATION to see opportunities, lively IMAGINATION to make use of them to your advantage, steady Ci INCENTR. ATION and strong MEMORY to solve the problems sure. to arise, and, most of all, an inflexible PURPOSE to accomplish your desire. Think of the man or woman you admire for achievements, and see if.this person ak in any one of these faculties. It is re than likely that he, or she, has a well uned brain engine—running sweetly along ways giving maximum power and speed ys getting the most out of life. sis the ideal of Pelmanism, but nearly ‘million happy Pelmanists in all parts of the vorld fact that ( d are living witnesses to the Pelmanism is more than a mere beautiful ideal. It is actually a process for tuning up all e mental faculties and making them work 'ovether for the greatest self-development pos- ‘ible to each Pelmanist. Is your mental engine missing on at least two cylinders? That this wonderful system is both practical and fascinatingly easy to learn is proved by the thousands of enthusiastic endorsements that the Pelman Institute is constantly receiving from students of Pelmanism. Here is what Mr. Ray Pedro, California, writes: “I have put the Pelman course into practice by going after the things I needed to achieve advancement. I have built a new home for myself and family; have developed a Hovey, of San YOUR BRAIN IS LIKE THIS ENGINE Check right now the ‘‘cylinders’’ where you feel that your ‘‘compression”"’ is poor Purpose Observation Will Power Imagination Concentration 1 Memory and broader lines of thinking a secured a position mucl ore adapted t ice and capabilities. I feel repaid for starting the course.” Mr. A. Gillespie, Vice-Pre i Peabody & Company, manufacturers of taste for study, and have best ex > & Collars, says: “Had I known at 30 what Pel Imanism has taught me since 50, many things in my life that were difficult would have been easy. If you have bat a spark of ambition or if you erely dissatisfied with the returns you are getting yur outlay of effort, subscribe for the Peln And Mr. C. B. Claflin, a merchant in Philadelphia, Pennsylvania, sums it all up the words: “TI have practically revolutionized my life by taking this course.” ; ; The Pelmanist as a business man is never far from A Pelmanist’s brain hits That is why over 650,000 of them are climbing the hills of Business *‘on high." opportunity. He sees it in places where the average eye yper training has SI rpened h Ss bse rva- ther mental faculties. He has a purpose mows he can “ Imagination cond he 1s His con is power achieve his aim ire strong; his w ill “captain of his s pul!’ Learn the “team-work” of the mind Lack « mention of all the benefits Pelmanisn your life, as easily and certainly as the Pelman Institute has prepared a free box \ y startle and amaze you. It shows how and wl is the only system of teaching ever devised for developing a/l the mental powers at time Whether ief glimpse of Pelmanism has attracted you or not you feel that you are weak or lack ing in some v: ntal attribute, or not—you should at least send for this remarkakle record and outline of Pelmanis t tual achievements, and its boundless possibilit Send Now for This Free Proof Pelmanism actually give s student New minds for old” d it does it in thr to Six nths, throug! ethod so novel, fascinating and that you look rward to each new lesson as you would to a pleasant V ig in the theatre You do not obligate yourself i ny way by sending e coupon b br you a copy of the nish free | t explair Pelmanism from start to h, and th of the ost convincing, untar letters fr Pelmanists, showing how this rkabl hod rev itionized their ves and for- une mea incre ng their earning capacity One f 1 t successful st es that | nt for tt book er t 3u € VI s that P ur is r er ur t { it 1 c I I r t lver was “the w t f lif it ll pa 4 to find t Pe ’ to 2.x ug 1 ink I t t elt improveme urse A eaithy cur Pe m pened t ent cted WW ly valuable benefit Send t ( while vou fe k ie it N il upo you. You risk n I and may uN galt than you ¢ possibly ) The Pelman Institute of Americ: Dept. 873 2575 Broadway New York y The Pelman Institute of America t Dept. 873, 2575 Broadway, New York i I want you to show me what Pelmanism has actu 1 Jone for nearly a million people Please send 1 your free book Chi places 1 nder no obligat 4 j Nar é Addres 1 1 Stat

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702 East 4ist Street, Dept.914 Chicago, Hil. a on pages 8 to 25

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28 POPULAR SCIENCE MONTHLY F= Gi. O< THE NEW "NATIONAL SET ‘i You Hear These Wherever You Go! These Great New Fox Trots Arcady An Orange Grove in California Roses of Picardy Sittin’ In a Corner

These Great New Song Successes

I’m Sitting Pretty In a Pretty Little City If the Rest of the World Don’t Want You

Linger Awhile , . : When It’s Night Time In Italy, _ ge yee — It’s Wednesday Over Here sa ~s a entucky, sure As Mamma Loves Papa, Papa Loves nipped Mamma When Lights Are Low “ 2 I Took the Fift h d These Wonderful New Waltzes °° Dolla 2 ry Sleep Stay Home, Little Girl, Stay Cielito Lindo (Beautiful Heaven) Home

Most Popular Fox Trots Son S and Waltzes On Eight 10-INCH Double Face Records A Sensational Offer! Here is a complete library of the new- i FOR ALL How Can It Be Made? anteed manufactured of highest quality and biggest hits in the music world. 16 wonderful songs, fox trots and waltzes that are sweeping the country, the most popular songs of TODAY, played by wonderful orchestras, sung by accom- plished artists. The most wonderful phonograph record bargain you have ever seen, made possible by quantity production and direct selling. Every record 10-inch size. Every record guar- est material, and to be satisfactory in every Way. These are the songs that are being sung, whistled and played everywhere; fox trots and waltzes that are being danced to all over the country; that are right now, today, the biggest hits on Broadway. Do not miss this wonderful opportunity; remember that these are brand new 10-inch records.

NATIONAL MUSIC LOVERS, Inc. Try these wonderful records in Dept. 1033, 218 Wést 40th Street, { your own home for 10 days. Note New York | the beauty of recording, the clear- ease st .f ys’ , ~ollectic ery latest songs = * - “ Se Please send me for 10 days’ trial, your collection of 16 very latest songs, 4 ness of tone, the catchiness of the tune, the wonderful volume of music. 5e€ fox trots and waltzes, on eight double-face ten-inch records. I will ve pay the postman only $2.98 plus delivery charges on arrival. This is | how durable and smooth these records are. You will wonder how we can gi not to be considered a purchase, however If the records do not come s = - : J ym- Up to my expectations, I reserve the right to return them at any time | uch a tremendous bargain. Quantity production, and selling direct- ee within 10 days and you will refund my money. (Outsid U. S., $3.50 factory-to-you; that is the whole secret. This is the greatest selection ot 1its on a eee , ever put out at one time, and this low price makes it the biggest record b: ae : Name..------ w------- wane eee e een ee-e- ever offered. Send no money now. Just mail coupon or letter. Give the postm : : 1 $2.98 plus the few cents delivery charges. Then plz iy all the records on your own Tl Address ’ 5 I 1 machine. If not pleased, return the records and we will refund your money plus $2 City State | postage both ways. This offer may never be repeated, so mail coupon at once fer If you like the ‘gre at songs from G ramd Opera you may also care * ° ad ? to have four of the most popular airs ever written, La Donna e | chi Mobile from Rigoletto; Madiey of Piiratore songs; Habanera from N & ] M +. I Its Carmen; and Soldiers’ Chorus, from Faust. All beautifully sung by t | . rreat artists, with full orchestra. If you care to have these Grand | a 10na uSsIC overs, nc. Im: Opera Songs, in ADDITION to the set listed above, place an 4 in | ™ Th — square at left. The price is only 89c for all four se iections. SOLD ONLY with the set advertised above—not sold separately. ] Dept. 1033, 218 West 40th Street, New York City cla

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les ‘wDle to each Pelmanist. The Pelmanist as a business man 1s never tar trom eo 1 City State POPULAR SCIENCE MONTHLY 29 Machines that Mark New Aerial Progress Giant Airplanes and Odd Helicopters to Conquer the Skies > THE LAST WORD IN NAVAL AIR ARMAMENT is the huge torpedo carrying airplane shown in full flight above. This machine, a Napier bi- plane built for the British navy, is said to represent a reduction in size, as compared with other types, without in the least sacrificing lifting capacity Ty Mii HERE IS THE WORLD’S LARGEST HYDROPLANE, recently completed at St. Raphael, France. The machine is a huge double “ biplane weighing 10 tons and driven by four motors of 1000 horse- powereach. The great streamlined body forms a spacious air coach handsomely furnished for passenger transportation. This body is built on a broad pontoon capable of riding the waves in the roughest weather. Note the unusual arrangement of the four wings in pairs FHQAQUQH WOK x ANNONA We UW d@deiildddddddiucecmpyfiy records 1 days. Note g, the clear: music. Se we can give direct- -from- ction ol hits cord bargain the postman OU.&U. n your own THE LATEST CONTESTANT for the money plus $250,000 British Air Ministry prize, of- ~ THN SAT AEN ee pon at once fered for a practical vertically rising ma- A HELICOPTER BUILT ‘ON "AIRPLANE LINES has sien chine, is the Omnivator, pictured above. designed by William J. Beach, author-inventor, of Australia and Its two side propellers are designed to New York City, who is shown above demonstrating a small Ce imitate tie movement of a bird’s wings. model of his invention. The upward movement of the strange ° The inventor, E. P. Johnson, of Chicago, machine is said to be produced by revolving planes acting on City claims it will fly backward or forward a series of four shutter-like planes that stabilize the machine

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POPULAR SCIENCE MONTHLY

Built to Grace a Drawing Room he

Grebe Broadcast Receiver Type CR-12. A 4-tube Re- ceiver combining Regen- eration and Tuned R.F, $1750 (Accessories extra) “There ie no calamity " HAT delight for all in the ever-fresh ae vase Sete Serine programs during the long, wintry PE too evenings to come. Today’s broadcasting Roce uot thy ncigitber's better than yesterday’s; tomorrow’s more ——<—<" fascinating than today’s. Tune in on this Oo; de if realm of entertainment, with a REBK, ro" Receiver Supplied in two types, each an Instrument 4 of rich, dignified beauty—the product of more than ten years of skillful development.

CR-12 is a 4-tube Instrument in which are com- ’ bined Regeneration and Tuned Radio Frequency é Amplification. 9) 3 CR-14isapopularly-priced3-tube dry cell Receiver employing Regeneration. The sockets accom- modate UV-199 or C-299 tubes without adapters. Both have beautiful wal- nut cabinets, employ - concealed dry batteries and are extremely sim- ple and economical to operate. Ask your quality dealer for a demonstration, or write us for full particulars. Nee i A. H. GREBE & CO.,, Inc. Van Wyck Blvd., Richmond Hill, N.Y. Western Branch: 451 East 3rd Street, Los Angeles, Cal. ae Grebe Broadcast Receiver Type CR-14. A3-tube Re-

(Accessories extra) U. S. Pat. No, 1,113,149

For wan For wan Forwan Allfor t 4 at a cr lives o needles No | was pl tention of the which 1 annour Shenan Lk After

ceiver ofexcep- tional value $] 10° Licensed under Armstrong

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