Popular Science Monthly 1923-12: Vol 103 Iss 6

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v= eRe prea acing -has a diameter of 400,- DECEMBER, 1923; Vol. 103, No. 6 25 cents a Copy; $2.50 a Year YOUNG fellow in our town used to have an exaggerated opinion of his own importance. He talked a lot and said little. Now he thinks a lot and talks little. He has been reading and thinking of recent revelations of science in the world of the inf- nitely large and the infinitely small. Such thought is good to reduce the ego of mortals. * * POPULAR SCIENCE MONTHLY Most Wonderfully Illustrated Magazine in the World Published in New York City at 225 West Thirty-ninth Street tem, so small that no human eye has ever seen it. Electrons, concentrated electrical charges, revolve with a velocity of 93,000 miles a second about a nucleus as the planets revolve about our sun. One thousand million million million of these electrons equal the weight of a single cigarette paper. A scientist explained that if one imagined an atom having a diameter of a mile, an electron moving NSIDER our stel- lar system, the Milky Way. It con- sists of millions of stars, In Next Month’s Issue The Story of the Mind—First article || P°* in it would be as large as a dining-table and the nucleus the size of a * * alongside of which our in an unusually helpful psycholog- sun, a giant compared to ical series by James J. Walsh, M.D., EAR’ the atom the earth, is but a dwarf. Ph. D., famous American surgeon apart and you will Antares, the largest star and psychologist. find it veritably alive yet measured, larger even than Betelgeuse, 000,000 miles. Our world, with its diameter of 8000 miles, compares with it about as does an anthill with the Wool- worth Building. ET in the depths of space are many other systems, perhaps larger than ours. If by some chance the earth Harnessing the River Jordan—How Science, in its restoration of the Holy Land, today is carrying out ancient Biblical prophecies. Jack Binns on Radio—An under- standable and usable article on the heterodyne receiver by the foremost writer on radio in America. ang Your New Car—Mechanical im- provements in the 1924 automobile. A practical article that will help you make your selection. And 200 other fascinating articles and pictures with a prodigious force. It has been pointed out that the electronic en- ergy in a glass of water is sufficient to propel the Leviathan to Europe and back at top speed. Science, inseparable twin to harness this tremen- dous power. One day it will do the work of the world. ok 1 should collide with one of these tremendous celestial bodies, it would disappear as quickly as a snowflake in a blast furnace. Romance is there—the romance of the infinitely big. And there is mystery, too—the | mystery of the un- known and the in- tangible. See Special Christmas Offer on page 88 - ON THIS planet, where a_ thousand miles is a great distance and the head of a pin is small, it is difficult to comprehend the infinite. We are in something of the position of moths, attracted by an arc light, striving to under- stand electricity. But * * OMANTIC also is the atom. Its wonders are invisibly small. Each atom is a miniature solar sys- 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, 1923, by 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 the ego. that for the young And _ they ises of world. POPT)I ap CHLKIDAICOR asnarm of Romance, is striving ~ -¢ a > oT -_oae «i stories of these won- — ders serve to reduce They did © man in our town. — lp men — understand the prom- — science for the future of the

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POPULAR SCIENCE MONTHLY 27 — } peea > eed - PSe¢ >@@« -ee¢a AK wt — LiA. > oe @ »eo = Paes peo be @a@ @ & 8 Men of the Hour in the Field of Science He as Timely Glimpses of 3 Master Craftsmen Who . 9 | Are Busy in the World’s = 3 | Workshops of Progress : i seen é irges, nt | cond : bout j aq : hon ae ee ee OO illion in ingle vat if rofa ving ge as | the ° ¥ of a : atom @) ¢ 1 will alive force. el DR. CHARLES P. STEINMETZ, world-famous electrical wizard. : d t ° In a recent remarkable prophecy of the world in 2023, he declared \ ou that we are on the threshold of an age that will witness a greater Cc en- , flowering of man’s ingenuity than the 100 years through which we t have just passed. He predicted that the time is coming when there Lg water i) | will be no long, back-breaking drudgery and when people will work ‘ el the 5 \ not more than four hours a day. rope | : me D | F. J. TURQUAND, London : : Bie 1 mining engineer (seated riving below), has perfected a deli- B cate instrument to test milk -men- by making impurities audible Jay it : over the telephone. He is shown demonstrating his ap- f th ) € paratus which, he says, ' is valuable also in de- & * tecting deadly choke damp in coal mines, thus preventing disastrous usand : } | is pin is finite. PROF. C. HAM- \ noths, B MOND, astronomer of , de the Naval Observatory, under- Washington, D. C., work- y. But ing- at a six-inch transit ‘ circle with which he tells : > won- the accuracy of time. He : reduce claims to have proved DR. RALPH H. McKEE, wy die that, clocks dn. aot ran Professor of Chemical En- “y } faster at night than in the gineering and Chemistry at | young 0 Columbia Univérsity. He town. i by —— has developed a new ¥ - method of manufacturing Db men _. “intarvin,” an artificial fat, ‘prom- — : the new remedy for diabetes { ‘Pp : discovered by Dr. M. Kahn. ce for if oe aye AE (ae 4g fs pi canon Sa cn el

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SS ee SS Se ee Ol POPULAR SCIENCE MONTHLY ar 49 wuy7 brought Menc ore to desire 15 natural ™ he ear sounds nos th or t asant ant than ere are ple as ounds @ Music + EE ION PASC NUT Sn vismte om

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POPULAR SCIENCE MONTHLY SUMNER N. BLOSSOM, Editor December, 1923 Will the ZR-1 Discover a Polar Paradise? HEE is one of the most astounding stories of scientific possibility ever published. Commander Green’s exclusive article has all the pungency of romantic fiction; at the same time it is founded on the scientific observations of a veteran arctic explorer, and ipa ovine ~~ fascinating gel _ praramy D Not since the days of Columbus has any venture held such power of grip- . metas ia a ping the world’s imagination as the proposed voyage of the ZR-1. noe’ Pg tho x coats he = In the issue of POPULAR SCIENCE MONTHLY for November, 1920, the North Pole next summer, it will prove, accorde prophecy was made that “‘a huge dirigible of the Zeppelin type will enable the ing to Vilhjalmur Stefansson, famous arctic explorer of the future to study the geography of the poles in a really scientific explorer, “one of the turning points in history” way.” Now this promise is to be fulfilled in the projected transpolar flight of the new navy dirigible next summer. What will be the outcome? Commander Green’s entrancing picture of a balmy polar paradise repre- sents, he says, simply a tremendous possibility of arctic aeronautic explora- tion. In his article he sets forth the facts as he has gathered them. Whether you agree with his theory or not, you will find it absorbingly fascinating. By Lieutenant-Commander Fitzhugh Green, U. S. N. N THE proposed transpolar flight of the huge new navy dirigible, the ZR-1 (the Shenandoah), next sum- mer, lies the most thrilling possibility that ever faced a single body of explorers: In the center of the unknown area of the Polar Sea may be discovered a vast continent heated by subterranean fires, and inhabited by the descendants of the lost Norwegian colony of Green- land! So wild is the idea as to tax the ™ most gullible im- ° agination. Yet it is vividly en- couraged and supported not only by history and tradition, but by the searching test of scientific analysis. — Witness the astounding facts: Within boundaries of the Polar Sea spreads the greatest unexplored area on the surface of the globe: 1,000,000 square miles on which no human eye-has gazed! Look at the map on page 31. Most of this enormous wilderness lies on the Alaskan side of the Pole. On the European side lies’ Iceland at a point corresponding roughly to the center of the unknown area opposite it across the top of the world. This fact is significant. Experts are in nearly unanimous agree- ment that a new arctic land will be found by the ZR-1. Doctor Harris, the tidal expert in Washington, D. C., long ago declared that the data he had worked out from polar ocean currents all.convinced him that the existence of a large land-mass near the North Pole ‘is indisputable. Add to this the array of evidence geologists adduce on the basis of terrific voleanic-activity along a well-defined line leading up the. North Pacific, through the: Japanese archipelago and the fiery Aleutians, and onward toward the Pole. This seismic axis plotted on the globe nearly bisects the unknown area of the Polar Ocean. Further, were this line swung through 180 degrees, it would touch Iceland, one of the most fiercely voleanic spots on earth. Another signi- ficant fact. Will the ancestors of the Lost Colony of Vi- kings who mysteriously vanished from Green- land centuries ago be found inhabiting a steam-heated polar continent? Eskimo tradi- Tae Gat ~~ Sapermeeg re teepaieateeepe I - Specs te rete es ere ne oe aged nt # ee Se easet a =* Ps RRS SEER ae Sac nero ones ~ Se i a Se Sad speasiec cakes SS ee yee RON Aga POSE OES

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30 POPULAR SCIENCE MONTEILY

Still more: Not meny years ago, in a particularly open season, the American whaler, Captain Keenan, reported he saw land northeast of a Point Barrow. Peary, from Cape Thomas Hubbard, sighted distant Such evidence is The new already peaks northwest. incontrovertible. continent seems within our grasp! So much for the land-mass. Now for its probable inhab- itants. Eric the Red dis- covered Greenland in 985 A.D. He brought back glow- ing tales of grassy fiords, long sunlit days, game-infested hills, ice-pans groan- ing under their bur- den of fat seals, bays teeming with fish.

Vikings Prosper Colonization be- ganatonce. Andso true did Eric’s bright tale prove that the Vikings greatly prospered. In the archives at Bergen may be seen today the receipts for their princely contribu- tions in ivory and oil to the ill-fated Crusades. The last ship known to have re- turned to Norway from her arctic col- onies arrived in the year 1410. We read that it brought a rich cargo; that its re- port was of happy, thriving Norsemen back north; of health and growing inde- pendence despite their rigorous environ- ment. Then, as in 1914, Europe became a shambles. Plague and war swept civiliza- tion. Pestilential disease ran a ghastly race with a horde of human murderers. Greenland fell out of the minds of man. Even the sea route north was forgot- a Lost Colony a World Riddle Dark ages passed. Slowly Nature bred again in men the will to search her world for knowledge and for wealth. Greenland was rediscovered. Hans Egede estab- lished the first modern settlement there in 1721. But the grim report he made was tragic beyond belief: The Norwegian colony, 10,000 people— perhaps 100,000—had, to a man, mysteri- ously disappeared! “The greatest riddle in the history of the world,” it has been called—the baffling mystery of the lost Norse colony. Where did they go? Where didn’t they go is a question more easily answered. Not to sea in ships, for they had but one or two; and Greenland, lying above the tree-line, gave them no timber for building more. Not slain by Eskimos, for Eskimos are the most peace-loving people in the world, knowing nothing of the art of war. Not, U. S. N.,

writes Commander Green. Lieut.-Com. Fitzhugh Green, from a_ photo- graph taken in the Arctic An Adventurer in the Icy Desert TH my own eyes I have seen in Greenland the ruined stone houses of the lost Norwegian colony,” “With Donald B. MacMillan I have tried to reach the polar continent, believed to lie in the Polar Sea north of Canada.”’ As an arctic explorer of wide experience, Commander Green—now aid to Admiral Williams, President of the Naval War College at Newport, R. I.—has made an exhaustive study of the fascinating possibilities of discovery of which he writes. his graduation from the United States Naval Academy at Annapolis, he joined the Crocker Land Arctic Expedition as en- gineer and physicist in 1913. 31% years in the polar regions. In the spring of 1914, with MacMillan and two Eskimos, he sledged more than 1000 miles up across Ellesmere Land and out into the Polar Sea in search of land that tidal experts insist must lie in this million square miles of unexplored area. They also explored an unknown portion of Axel Heiberg’s Land. Grand Fleet in European waters. Following The next year, after their relief ship had become imprisoned in the ice of Smith . Sound, Commander Green, with two other members of the expedition, sledged south, passing down the uninhabited portion of the Greenland coast and reaching the Danish colonies five months later, in the spring of 1916. Reaching New York by way of Copenhagen in the autumn, he joined the Atlantic Fleet on regular duty. The following spring he became Flag Lieutenant to Admiral Rogers in command.of the division of United States battleships attached to the British they say, even to this day, “‘in the direction of the coastal _ trail-route north.” This route is that taken © by our American expedi- tions. Peary, Kane, and Hayes all used it. It always has been the easi- est route as well as the most productive of natural food in seal and walrus. For our-explorers it has been a hard trail. But for the Norwegian colonists whose forebears had spent 10 generations north of the arctic circle it must have been less difficult to travel than were the west- ern plains for our Ameri- can pioneers. Lured Northward Picture the terrible situ- ation in which the de- serted Norsemen in Green- land found themselves: No outlet for their trade. No source of supply for the little but indispensable luxuries of life. No access to friends and families back home. _ A generation—two, per- haps—of heartbreak .nd He spent

like Europe, swept by some dread germ of awful virulence, for germs don’t thrive in polar regions. What then? Examine the Eskimo tradition: It paints in vivid terms the White Men swarming suddenly north to a wonderland the natives long had known. Because of evil spirits, no Eskimo had ever dared this trail. “The land is warm; is clothed in sum- mer verdure the year around; is popu- lated by fat caribou and musk-ox. It lies,” of longing; unhappiness goading the younger men to travel northward. Perhaps a route to southern lands lay that way. Suddenly like a bombshell breaks upon the weary colony the wonderful news: ‘“‘We’ve found a polar paradise! Sun- shine! Game! Grass! One moon’s easy journey north! A short lap on the sea ice! Come!’ What had they to wait for? A century had passed since the last ship sailed. The last man who had seen a real Norwegian had died. The homeland was but a myth. So they “packed and, singing songs, departed,’ the native legend puts it,

Washday in Iceland, where hot springs and Green, to believe that Iceland has a geo-

a —_ we fn am 2 Ge ont

boiling mud abound. An engineering scheme for steamheating the whole island by harness- ing its steaming’ geysers has been projected recently. It is no idle dream, says Commander

graphical mate on the opposite side of the Pole—a polar continent of mild climate and luxuriant vegetation, warmed the year round by hot springs and geysers.

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to this tion of il-route t taken © expedi- 1e, and it. ne easi- as the natural walrus. it has But for slonists d spent rth of t must cult to e west- Ameri- ard le situ- he de- Green- selves: - trade. oly for ensable ) access amilies vO, per- ak und ppiness er men oute to (Ss upon - news: Sun- "$s easy the sea -entury d. The ‘wegian 2 myth. songs, juts it, RAE? POPULAR SCIENCE MONTHLY Our artist’s conception of the discovery of a possible “‘polar paradise”’ by the ZR-1, based on Commander Green’s imaginative article. This land, the explorer believes, may be about the size of the state of Pennsylvania, and may be encircled by a lofty, volcanic range of “suddenly to the northward.” They never returned. This fact is not at all surprising if what we think is true—that they found a land of milk and honey in the very cen- ter of the polar pack. And it is perfectly logical to suppose that their descendants will be. found up there next summer by the dirigible ZR-1, in dramatic isolation. Go back to the scientific data on which we base this amaz- ing assumption. Iceland’s collection of volcanoes is unsurpassed. She has 107 major craters within her tiny limits, and thousands of minor ones. Ice- land’s climate is tem- perate despite its arc- tic situation. The peace, the health, and . the prosperity of Iceland’s inhabitants were sustained by its natural warmth dur- ing the 200 years of isola- tion from Europe that. it suffered at. the same time and. for the same reasons that the Greenlandic Norse- men were deserted. ? ' Moreover, Iceland’s lava flows are..by no means always from, conventional craters. The greatest of PACK ICE WM 14 How the barrier moun- tain range of the new land may appear from the distance mountains buried in eternal ice and snow. Behind a veil of fog may lie a fertile plateau where heat from hot springs, geysers, and boiling pools defies the cold. The illustration shows the possible habitations of the modern descendants of a vanished race of Norsemen them have come quietly from fissures in the level land. We may deduce that subterranean fires smolder near the surface. It is not uncommon for the inhabitants to be forewarned of eruption by sudden melting of the snow and ice. Hot springs and boiling mud _are found in every part of Iceland. There has been projected an engineering scheme for heating the whole island by harnessing its steaming geysers. In this con- nection it is interesting to compare the mean annual tem- perature of Iceland— 34° F.—with that of Green- land at the same latitude— minus 15° F. During the summer Icelanders enjoy a VAPOR rf FERTILE PLATEAU :. —— , = 4e/ ad) : 7 Yj 4 CES hd hi f This map shows the proposed transpolar air route of the ZR-1: from Alaska to Norway. Cutting the distance to European and Asiatic capitals from 11,000 to 5000 miles, this route would pass across what many geologists believe to be an unexplored polar land on the opposite side of the Pole from Iceland. The curving dotted line indicates the possible route which the “lost Norsemen” may have followed to this imagined arctic wonderland period quite comparable to that of our own New England States. Averages run up to 60° F. It is no idle dream to claim that Iceland has a mate across the way. Geo- graphical twins are common on our globe: Cape Horn and the Cape of Good Hope; the Mediterranean and x tle Caribbean; islands fz - off Alaska and Japan; Y AS », and so on. P GOR” (Turn to page 136) > VOLCANO So - W117. PACK ICE Commander Green’s own idealistic drawing, showing a cross section of the imagined arctic continent —an undulating. fertile plateau, steam- heated by hot springs, geysers, and boiling pools and rimmed by a volcanic range of mountains. Behind this barrier rises a veil of vapor

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32 POPULAR SCIENCE MONTHLY Can Man Rob Earthquakes of Their Terror? | By R. E. Martin HILE Japan clears the wreckage of Le, the cities of Tokio and Yokohama, leveled by the recent earthquake, the forces of science a are being marshalled to find a way to pre- vent repetition any- where on earth of what is now known to have been the most terrible disaster in history. SOUTH ATLANTIC Not that science OCEAN hopes to prevent other earthquakes. These Si TASMANIA 97 Y= NORTH PACIFIC OCEAN NEW ZEALAND, the friction between the blocks, something will give. They will buckle, and the buck- ling will correspond in a way to the move- ment of the earth’s crust that causes an earthquake. The most unsettled part of the earth’s sur- face is the’ western shore of the Pacific Ocean. Here the crust is being thrust up- ward, giving rise to steep slopes. It was such a buckling of the cataclysms of nature undoubtedly are due to structural changes in the earth itself, and are consequently be- yond the power of man to control. But science does expect in time to remove the chance of any such terrible loss of life and prop- erty as marked the Japanese catastrophe. Means of forecasting earthquakes so that the inhabitants of a threatened area may flee in safety before the quake arrives, and the construction of earthquake-proof buildings—these are the goals toward which science is working. In the opinion of leading scientists the day is not far distant when people may live in larger security in places like Japan where earth- quakes are of frequent occurrence. 4000 Earthquakes a Year The tremendous importance of this task in which some progress already has been made is evident when we consider that 160,000 earthquakes actually have been catalogued and that about 4000 earthquakes are felt each year in different parts of the world. Probably the most important work that has been done in the observation of the causes and nature of earthquakes has been accomplished since the beginning of the twentieth century. Previously all earthquakes were generally regarded as being of volcanic origin. Scientists now believe that most earthquakes are caused by wrinkling and slipping cf part of the earth’s crust, caused by strain resulting from shrinkage of the more plastic in- terior of the earth, contortion of the earth’s strata, or changes in pressure in the crust itself. However, in some cases, subterranean volcanic action is believed to have been the cause of certain quakes. The crust of the edtth may be consid- ered as a relatively thin skin or rind of rock, about five miles in thickness. As stone broken in a quarry splits along certain definite lines, so this outer cover- ing of the earth tends to split along lines of weakness which geologists know as “faults.” Variations in pressure—which may be caused by the weight of moun- tential disaster. The black lines mark earthquake zones that girdle the world, forming narrow belts of po- Note that the United States, except for the Pacific Coast, appar- ently is free from danger of quakes. The most unsettled part of the earth’s surface is the western shore of the Pacific Ocean. This map was prepared by Prof. F. Omori, head of the Imperial Earthquake Investigation Committee of Japan, who nearly two years ago made the forecast that severe shocks would ,be experienced within How the recent earthquake in Japan split and crumbled the Tokio- Yokohama high- way near Kawasaki, opening great gaps tains or of the water in theocean— cause move- ments or dislodge- ments between the sec- tions of crust, which, of course, are constantly seeking to remain in equilibrium. The situation may be compared with a row of building blocks, laid side by side and sub- jected to pressure from bovn ends. When the pressure becomes too great to be resisted by ARM SHAKES BUILDING HORIZONTALLY & POPULAR SCIENCE MONTHLY earth’s crust along the cracks believed to ex- ist in the bottom of the Tuscarora Deep, off the coast of Japan, that caused the recent disaster, according to theories so far ad- vanced. The proximity of the Japanese coast to this great trough-like “deep,” which goes down more than five miles, and the numerous earthquakes experi- enced by Japan, lend weight to the theory that pressure exerted by this tremendous volume of water is the cause of such dis- turbances. Earthquakes under the sea are called seaquakes. So tremendous are the waves that they can travel at a rate of four or five hundred miles an hour, and still be detected after a journey of more than 10,000 miles. Earthquakes are known to have oc- curred in the east- ern part of the six years LEVERS PRODUCE To test the ability of vari- ous types of buildings to withstand earthquakes, Professors B. Mano and A. Inokuty, of Japan, have invented the engine- driven sheking table shown above. A model building is placed on a platform that is vibrated horizontally and vertically by means of eccentrics and levers to duplicate typical earthquake movements VERTICAL VIBRATIONS ee ee ee ee ee ee ee | ee ee. oe eo en |

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S tween ething y will buck- ond in move- parth’s ses an settled ’s sur- estern Pacific e crust it up- ise to [t was of the ng the to ex- 1 of the p, off Japan, recent ing to ir ad- panese deep,” miles, experi- theory endous ch dis- called waves four or still be e than % kes are ave oc- ie east- of the ZB 4 y ODUCE RATIONS r of vari- dings to hquakes, ano and POPULAR SCIENCE MONTHLY L 47 oo , | eer ‘ ABR nes ie Senta me sah es eam tsar cele m ci A SUDDEN FRACTURE United States at various times, but science scouts the notion of any quake of a devas- tating sort ever visiting any but the west- ern coast of America. Following the Japanese shock, Dr. Bailey Willis, emeritus professor of geol- ogy at Stanford University, asserted un- equivocally that man and not nature is to blame for the disastrous consequences of earthquakes in localities like Japan, Chile, and California, which are known to be in the earthquake zone. His statement was based on observations in Chile, where he had been investigating causes of earth- quakes for the Carnegie Institution of Washington, D. C. He pointed out that it is not the earthquakes themselves—the actual ground tremors—that cause the frightful loss of life, but the events that follow the quakes—the falling of ma- sonry, the fires, the floods from reser- voirs and similar things. “To construct a house that will with- stand an earthquake is not difficult if you can command the right materials and good carpenters,’ says Doctor Willis. “A point that has not been recognized generally by architects @r engineers is that it is the earth that moves, while the house tries to stand still. If you could put a ball bearing between your house and its founda-. tions, it would be safe in time of earth- quake. This idea is embodied in every instrument for recording earthquakes and was applied many years ago by Sir John Milne to the construction of a A scene of appalling devastation along the waterfront of Yokohama, following the terrific earthquake and tidal wave Scientists believe now that most earthquakes are caused by the of September. lieved to be the result of WHAT’S INSIDE THE EARTH Recent study of earthquake waves has led to new scientific discoveries indicating that the earth’s interior may be divided into three definite zones—a rigid, elastic outer shell; a semirigid metallic intermediate zone, and cen- tral non-rigid core. This theory is deduced from seismographic records showing that the course of earthquake waves through the earth is curved toward the surface; therefore that the earth is denser and less rigid at its center. The three zones of the earth’s interior are indicated in the illustration, which shows how volcanic outbursts throw up millions of tons of dust that travels entirely around the earth SURFACE WHERE WAVES CHANGE k:. | COURSE "4 SEMI-RIGID RIGID SHELL NON-RIGID COREL... DEADENS SOME je WAVES POPULAR SCIENCE MONTHLY fracture and slipping of the earth’s crust as the earth contracts (see diagram at the left). Some quakes, however, are be- volcanic action, as shown at the right VOLCANIC ACTION NS lighthouse in Japan. I believe it can be introduced successfully in some combina- tion of bearings, springs, or shock absorb- ers. “For the ordinary house a broad ditch packed with cobblestones on which there rests a well braced frame of heavy beams Would not be a bad substitute. It would allow the ground toslide around under the house, which could be jacked back into position with reference to such unstable things as trees, garden walks, and roads at your convenience.” Doctor Willis adds that the displace- ment within the earth that results in rock slips that science now regards as the cause of earthquakes is developing below the surface for months before the quake occurs. This displacement usually does not actually reach the surface, but produces vibrations or waves that can be recorded by special instruments as a means of obtaining forewarning of the coming quake. The vibrations travel great distances at high velocity before they die out. “The instruments will have to be set up in many places,” said Doctor Willis, “‘and records kept for years be- fore the science of predicting earth- quakes is set on a firm basis. I think it is not at all unlikely that in the future earthquakes can be predicted much as the weather is predicted now. Warnings can be sent to threatened districts and measures taken by the populations to save themselves.” subterranean jon yet Saab Die ebait GBs pr Sect ial lees te Se tes ett : ; cepacia St i cit eT pT a i aC SES phistsc terete ont et Foca Saree Neer Shi Oe

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seepamtepenne : 5 \ i mrt eI SITS POPULAR SCIENCE MONTHLY The Story of the Mind The Most permet tise Serzes Ever Published By James J. Walsh, M.D., Ph.D. S A physician I have always been inclined to think that whenever anybody dies of typhoid fever, somebody ought to be hanged, because there has been criminal negligence somewhere; some one has permitted contami- nating materials from a typhoid patient to get into the food or drink of a healthy person. Banish Fear and Ignorance It is the same sort of crime for human beings to allow their efforts to be palsied by dread of failure. it is criminal to allow the initiative to be hampered by lack of confidence; to restrict the dis- play of energies just because of a lack of self understanding. This can be prevented by realizing that what one individual can do, others can do, and that the only reason for failure is lack of knowledge of : personal powers and neglect to use them. | “But how may I acquire this knowledge?”’ you may ask. The answer is simple—through psy- chology. And what is_ psychology? Psyche is a Greek word, meaning “mind,” and logia is another, meaning “knowledge.” Psychology—frequently misunderstood and generally cloaked in long, mysterious words—is simply knowl- edge of the mind. One of our newest sciences, it has a more intimate personal appeal and offers a wider application in practical usefulness to you and to me than almost any other science, old or new It brings us knowledge of our own minds—the way in which they work, their powers, capa- a firmly knitted mass that proved irresistible ir action. It took the crisis of early 1918, when the fate of nations and the future of civilization seemed to hang by a thread, to bring forth all the latent power within him. If it had not been for the Civil War, our own great General Grant would have sunk into a nameless Dr. James J. Walsh writer of textbooks on tactics and strat- egy. That was all. But he proved to be one of the greatest men of history, capable of lending something of his own soul to millions of men and of welding them into grave after a commonplace and almost useless life. As it was, he proved one of the greatest leaders of the world’s history. War afforded the opportunity for Foch and Grant, but it did not make them. These men knew themselves. They knew the en- ergy and power that was hidden within themselves. And they knew how to use these powers. Therein lay their greatness. Every Task a Test We can’t all lead armies, but every task in our daily lives affords an opportunity to do something a little better than we ever have done it before, or to do it in a new way. We succeed or we fail according to whether or not we know our own mental _ Starting line in a foot race, only one can win, though they all have had equal training and practice in running. The winner possesses natural advantages in speed and stamina that training and practice will not supply to the others. But through training and practice, through developing the best there is in them, all 10 probably have learned to run faster than any of those who watch the race from the grandstand. So it is with psychology. Learning to draw on the hidden powers of your mind and to put them to use may not enable you always to outstrip those >. powers and how to use them. ; Of 10 men who crouch at the bilities, possébilities, and shortcomings. And, what is with superior mental gifts. But undoubtedly it will give more important, it shows us how to make practical use of this knowledge—how to find greater happiness, health, and power through our hidden mental resources. Why Men Fail A great many men fail in life, not because they lack talent, but because they fail to employ their minds prop- erly; because they do not realize or use the qualities they possess. When critical emergencies arise, men often prove to have hidden genius for leadership and unsus- pected power of accomplish- ment. Who ever heard of Marshal Foch before the war? Only a few professors of military science who knew him as a N ABSORBING story, which in its won- derful scope staggers imagination itself, is ‘‘The Story of the Mind,’’ to be told by Doctor Walsh, beginning in the next issue. On this page the famous American surgeon and psychologist tells why he is writing the series for POPULAR SCIENCE MONTHLY. In it for the first time a scientist of distinc- tion will tell us in simple, non-technical words that may be grasped by anybody, how to obtain happiness, health, and power through the hidden resources of the mind. Doctor Walsh’s psychology is the psychology of business, the home, and every-day life. With fascinating fact and parallel he demons strates that we may put our thoughts to work for definite external ends. And—he shows us how to do it. Doctor Walsh’s first article, ‘“The Machinery of the Mind,”’ will appear in the January issue of POPULAR SCIENCE MONTHLY, on sale at your newsdealer’s, December 10. puldinpmenbenesind cose: teas Sundeenteabiaiesieaeanad terre POPULAR SCIENCE MONTHLY you a tremendous advantage over those who merely sit by idly, unconscious of the well- spring of power that is within themselves. Psychology the Key The aim, then, of practical psychology, or the knowledge © of yourself as applied to your- ~ self, is to enable you to bring out and use what is best in you. An understanding of it may mean the difference be- tween succéss or failure in your life. Psychology is the key that will open the door to the wondrous storehouse of hid- den powers contained in your — mind, and in the series of — articles that I am about to begin in PopuLAR SCIENCE ~ MOonTAaLY, I shall endeavor to put that key in your hands.

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ion. It ons and to hang e latent been for General 1ameless - almost > proved 's of the ortunity t did not n knew the en- ; hidden ad they powers. S. est nies, but ily lives ' to do than we or to do icceed or ether or . mental em. h at the ace, only r all have ractice in possesses | stamina ot supply ning and the best bly have of those indstand. arning to our mind ot enable will give dvantage ely sit by the well- is within Key practical nowledge d to your- 1 to bring is best in ding of it rence be- sa failure in » key that r to the se of hid- ed in your series of — about to _ SCIENCE endeavor — our hands. By John S. Seymour, Formerly United States Commissioner of Patents AM to select the 10 greatest inventors ] of modern times, and in doing so my guide and chart necessarily must be the history of past achievements as re- flected in present-day civilization. When mankind began on earth, hun- dreds of thousands of years ago, there was no knowledge of fire or of pottery, of the bow and arrow, of domestic animals, of iron or of writing. There was no articulate speech. In the progress through savagery and barbarism, this knowledge was ac- quired little by little, and with it came the beginnings of civilization. From the time of the revolutionary dis- covery of fire the progress of invention was steady but unspectacular until 400 a tremendous impulse to civilization. These discoveries were gunpowder, the mariner’s compass, paper, and the print- ing press, the Copernicus demonstration that the sun, and not the earth, was the center of the solar system, and the dis- covery of America. Pathfinders of Modern Progress Then began the era of modern progress. From this era I have selected the 10 in- ventors whom I consider the greatest, basing my judgment on their work—its utility, originality, and its permanent value in meeting the needs of mankind. These 10 greatest, all of whom have lived within the last 150 years, are: Eli Whitney Charles Goodyear Samuel F. B. Morse Alexander Graham Bell Nikola Tesla Cyrus Hall McCormick Wilbur Wright Here we have the creators of the cotton Elias Howe Sir Henry Bessemer Thomas A. Edison pasion 5 gin, the vulcanizing rubber process, the telegraph, the telephone, the reaper, the sewing machine, the quantity production of steel, the incandescent light, the alter- nating current, and aviation; inventions great in themselves and each of them stepping stanes to.greater benefits to. men. years ago, when a series of discoveries gave ~ POPULAR SCIENCE MONTHLY The 10 Greatest Inventors And What They Have Given to Modern Civilization 35 gt Eli Whitney’s cotton gin dates back to 1793, 50 years before the telegraph of Morse, the sewing machine of Howe, the vulcanization of rubber by Goodyear and the reaper of McCormick. Among the 10 immortals of modern in- vention Whitney was the pioneer, not only because he invented the cotton gin, but POPULAR SCIENCE MONTHLY because he led the way in a development from which most great manufacturing enterprises of today draw their life blood —the standardization of parts. Firearms were the principal mechanical contri- vances of Whitney’s day. They were made almost entirely by hand, and no two cor- responding parts were exactly alike. Whitney was the first to realize that by making duplicate parts interchangeable for repairs, an appalling waste in material and labor would be eliminated. In achiev- ing this end, he paved the way for the quantity production of watches, motor cars, and thousands of mechanical articles in use today. Whitney’s invention of the cotton gin was original and basic and useful. The cotton that we use today in myriad forms and fabrics, would not be ours in the huge quantities we need and at prices we can afford to pay had not Whitney’s genius prepared and lighted the way. Father of the Rubber Industry To Charles Goodyear we owe our mul- tifarious use of rubber—waterproof shoes and clothing, fire hose, combs, insulation for electric wires, rubber tires, and even golf balls. . Prior to Goodyear, the treat- ment of rubber was primitive, faulty, and unsatisfactory. In. hot weather the rub- ber became too soft. In cold weather it was too hard. Daniel Webster, describing his experience with a rubber cloak and hat, made prior to Good- year’s discoveries, said: “I put the cloak outdoors one cold day, and it stood alone. This inter- ested me and I tried placing the hat on the top of the coat. The effect was __ strikingly lifelike and pas- sers-by, seeing the effigy on the outside, thought it was myself 37

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mE WEN | ; eS TES se es mono -kitchen stove. and hailed me in a neighborly fashion.” Chance played a part in Goodyear’s success. He accidentally placed a piece of rubber mixed with sulphur on the Instead of melting in con- tact with the hot iron, the mixture be- came hard. Subjecting the hardened specimen to further heat altered it not a bit, nor did it lose its flexibility when left outside the house in the winter air until morning. The problem of vulcanizing rubber was solved and Charles Goodyear earned his place among the great path- finders of human progress. A chance conversation played its part in furnishing the world with the electric telegraph, uniting the ends of the earth, pulling down the barrier of time and bridging a thousand gulfs. How Morse Conceived Telegraph At the age of 40, Samuel Finley Breese Morse was a successful artist. Returning from Europe in 1832, after a trip abroad to widen his knowledge of art, he heard a fellow passenger describing a recent elec- trical experiment. An electric current had been passed through a chain and bright flashes of light were visible among the links. To Morse, though untrained in science, -occurred instantly the thought, “if electricity can be made visible it can be employed to carry messages.” Before the ship reached New York, Morse had evolved the general scheme of the Morse Code, and had even named the invention he intended to make some day, the “telegraph.” As he left the ship he said to the captain, ‘If you hear of the ‘telegraph’ some day as the wonder of the world, remember that the discovery was made on your ship.” In January, 1838, his first message was clicked off over three miles of wire stretched about the room in which he ethtmmttieinienisaeneini ——_ — POPULAR SCIENCE MONTHLY worked with his associate, Alfred Vail. On May 1, 1844, when the Baltimore and Washington line had been completed, Morse signalled the nomination of Clay for President to the national capital, where the news was received with amaze- ment. Morse lived to the age of 81, and saw the earth engirdled by wires. No man holds a more secure place among the great. Alexander Graham Bell is the real father of the telephone, while Reis, Edi- son, Gray, Dolbear, Berliner, Hughes, Blake, and others are supporting con- tributors. Others had the interrupted current; Bell had the continuous undulat- ing current. It is incorrect to say that the telephone transmits speech. It transmits only a small, silent, continuous variable electric current and thereby at the receiving end Ir POPULAR SCIENCE MONTHLY a a a -s speech is reproduced by the vibrations of a diaphragm. In his application for his fundamental patent in 1876, Bell said nothing about transmitting speech nor reproducing speech at a distant point; his invention up to then was concerned with the reproduction of pitch and music. Then some one accidentally spoke into the transmitter and to the astonishment of all, the words were reproduced at the receiving station. The telephone was complete before it was known that it could reproduce speech. Once regarded as a toy, it has experienced an amazing growth, more intensive in America than anywhere else. Today there are 14,000,- 000 telephones in the United States averaging 35,000,000 messages a day. McCormick's Reaper Was Sneered At Through the reaper of Cyrus Hall McCormick the world gets its bread. Yet when this machine was first exhibited at the World’s Fair in London, the public smiled dubiously and the London Times ridiculed the contrivance as ‘‘a cross be- tween a circus chariot, a wheelbarrow, and a flying machine.” McCormick’s father had tried to de- velop a reaping machine and the son be- gan work on a reaper during his boyhood days. By 1831 the younger McCormick had developed a ma- chine that cut six

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= a tions of a . for his 3ell said 2ech nor it point; oncerned id music. oke into nishment d at the one was that it regarded amazing ica than 14,000,- 1 States a day. eered Al us Hall sad. Yet ibited at 1e public yn Times cross be- slbarrow, d to de- 2 son be- boyhood 1831 the ‘Cormick ed a ma- t cut six acres of oats in one afternoon—equivalent to the work of six men with the scythe. Forty-six other inventors before Mc- Cormick had attempted to develop a mechanical harvester and had failed. Cyrus Hall McCormick levelled the ob- stacles and made a device that was revo- lutionary and epochal. The descendants of his first reaper still harvest the grain crops of the world. Howe and His Sewing Machine Circumstances were a powerful factor in the invention of the sewing machine, the greatest of all labor savers for the home. Elias Howe was lame and sickly. His wife contributed to the family in- come by sewing. Unable, because of his health, to relieve her from her irksome labor, Howe sought to lighten it by de- vising a machine. To imitate the motions with which a woman sewed he produced a _ needle pointed at both ends with an eye in the middle, which worked up and down. But after repeated failures Howe saw that the machine should have characteristic mo- tions of its own. In applying this thought, Howe made use of the shuttle with which he had become familiar in working with the looms of the mills. At last he evolved a lockstitch ‘from the shuttle and gave the world the first POPULAR SCIENCE MONTHLY successful sewing machine in April, 1845. The number of useful articles made cheap and available by the sewing ma- chine runs into the thousands. Few in- ventors of all time have performed a more useful work than Elias Howe. The machinery of today that produces the food we eat, the clothes we wear, the cars we ride in, the offices and factories we work in, the rails on which we travel, is linked with the epoch-making material in the world’s history—steel. Steel in small quantity was the posses- sion of mankind for many centuries. But —____— 4 quantity steel marked the beginning of a new era—the modern age of steel. This age was born of a boy’s fondness for cast- ing mixtures from type metal. That boy was Henry Bessemer of England. Through his persistent genius he became the in- ventor of the Bessemer process of convert- ing pig iron into steel and by that inven- POPULAR SCIENCE MONTHLY 37 tion takes his place among the great. This idea of converting iron into steel originated in Bessemer’s efforts for devis- ing heavier projectiles for cannon. The remark of an army officer that heavier projectiles would be of little value without stronger steel for the guns, stirred Besse- mer on to experiments with molten iron. Soon he discovered that when a mass of molten iron came into contact with air un- der specific conditions, the carbon content, and therefore the hardness of the metal, could be controlled : It was only a short step to the comple- tion of the process of converting pig iron into steel by forcing air into the molten metal, a process that brought steel into every-day use, in quantity, and created the modern industrial giant with its rail- roads, bridges, ships, automobiles, and skyscrapers. Paralleling the age of steel is the new age of electricity, which, though still in its infancy, already is remaking the world, linking states and nations with networks of quick communication, lighting homes, supplying conveniences and labor-saving instruments and carrying the power of rivers and streams to turn the wheels of industry and to run our trains. Cheaper Power from Waterfalls Until recent years the factory had to be built alongside the waterfall. This in- volved. expensive transportation of prod- ucts to distant markets. Now a turbine and a generator at the waterfall may sup- ply cheap power to a factory a hundred miles away, and to hundreds of interven- ing small power users. The possibilities of electricity in the next century baffle the imagination; but we have the word of no less an authority than Charles P. Steinmetz that they will far eclipse the achievements of the last hundred years. _ (Turn to page 137) és a? 39 *

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aerer ERAT RIN 1 : | j Pe) i Al { i ! Power and Light from the. POPULAR SCIENCE MONTHLY Limitless Winds By F. A. Platte Instructor, Department of Physics, Columbia University entire force of the wind for power produc- tion. In the picture at the top of this page the wind is blowing from the direc- tion of the observer. Under the same conditions in any other type of windmill a developments in methods I: THE light of present-day of capturing and utilizing natural sources of power, most persons probably look upon the windmill, devised by man some time prior to the twelfth cen- tury, as hopelessly obsolete, except in isolated sections. Yet, in the opinion of leading engineers, this is far from being the case. Improved windmills, they say, not only are valuable ad- juncts to modern power-gener- ating devices, but they possess individual merits of their own. In fact, they are so useful for many sorts of power work that they may find more extensive use in the future than in any period in history. May Drive Locomotives A striking example of the possibilities of the modern windmill is found in East Prussia, Germany. There 11 windmills of the type pictured on this page have been con- structed recently to supply electric power during the exist- ing coal shortage. So efficiently have the wind motors operated in supplying current for elec- tric light and to run irrigation machinery, that steps now are being taken to use wind-gen- erated power to drive locomo- tives of a local railroad that was forced to suspend be- cause of the nationwide coal shortage. The power generated by revolution of the windmill wings turns a dynamo, and the energy produced is held in storage batteries. This method of transforming the power of the wind into electric current has been employed before in this and other countries, This photograph shows one of the giant windmill power stations established in East Prussia to generate electricity for light and power during coal shortage. They may be used to run railway trains the wind wheel would be on the observer’s side of the tower. The design of the wings is simple yet original. Every known scientific fact regarding windmills -and wind motors was taken into consideration in Our artist’s conception of the. wind-motor system, showing the inside of the power plant and transmission lines their construction in order to produce maximum power from minimum air movement. The wings were designed by a noted manufacturer of airplane propellors, and were tested in the aerodynamic. laboratories at Géttingen, Germany, before installation. Moved by Light Breeze A breeze barely sufficient to stir the leaves of the trees will set the great wings in motion, although the circle they de- scribe is almost 60 feet in diam- eter. Once started, they will continue to revolve as long as there is the faintest movement in the air. A normal wind will produce about 40 horsepower and a strong wind 70. On days when every other windmill near by is still, those of the new - design are supplying power. Aningenious “brake” pre- vents the arms from turning too rapidly in a gale. At the tip of each arm is a disk that rises from centrifugal force as the speed of the wings increases and opposes their motion. The faster the wings turn, the farther out these disks extend, so that no matter how strong the wind, the speed of the wind wheel is always kept within reasonable bounds. The towers upon which. the arms are mounted are about 50 feet but the wind motors -con- structed in Germany. are unique in many important particulars. For one thing, the new windmill, unlike all other types, requires no indicator, or tail, to keep it headed to the wind, and its blades always present their maxi- mum surface to the wind. Its wind wheel is self-adjust- ing. Such an effect is pro- duced by having the blades turn about a revolving wheel. that rests on ball bearings and automatically keeps.its axis at right angles to the direction of the wind. This feature permits the wind wheel to utilize the ‘(Wind Power a Substitute for. Coal’’ AMES LORING ARNOLD, professor of electrical en- gineering at New York University, commenting on the . German wind motors described on this page, says: “Utilizing the wind as a source of electric power is entirely feasible from an engineering point of view. electricity, of course, would vary according to the prevalence of wind, but the energy produced could be handled exactly as in the automobile, where the generator speed varies with the rapidity with which the car is moving. That is to say, the intermittent power could be led into storage batteries from which electricity at constant voltage could be procured for motors and lights. “The principal reason why we have not utilized the wind for the production df electric power in America is that the installation of windmills is expensive when compared with cost of coal and water plants. us of constant power. But should coal become too expensive or should there be a dearth of it such as now exists in Ger- many, we might have to turn to intermittent wind power.”’ The supply of Also, coal and water assure high. They are cylindrical in shape, built of iron and cement. The construction cost of the wind motors is said to be relatively low, considering the amount of power they. produce. American and Eu- Topean engineers are watch- ing the new method of har- nessing the wind with eager interest. They see in it a valuable auxiliary to our present methods of produc- ing electric power. A resident of East Cleve- land, Ohio, who lights his home with power generated by a windmill of a different type, described on page 69 of this issue, testifies to its = za = —~s = -_ POPULAR SCIENCE MONTHLY as a ' efficiency and economy. ik ne Ne aN ie ai ele ti Bs pages Cage ee ene Sie WES ee

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strong wheel ounds. $ are 0 feet ndrical yn and ost of d to be dering r they nd Eu- watch- of har- eager nit a o our roduc- Cleve- its his erated ferent age 69 to its y- Rd a! as ee Apia atats MMOL POPULAR SCIENCE MONTHLY eg poll Divers Battle Hungry Sharks to Spear Sunken Gold - THIS picture our artist portrays vividly the dramatic adventures of divers in their hunt for the $30,000,000 of golden treasure that dropped into the ooze of the ocean bed when a German submarine sank the White Star liner Laurentic off the Irish coast during the war. Battling ferocious sharks with knives, 90 feet below the surface of the sea, these _ intrepid deep-sea hunters have succeeded in recovering all but 30 bars of the gold bullion that was being carried to American bankers when the Laurentic went to the bottom. As they grope among the bones of the sunken ship, the divers use a sensitive divining spear, with galvanometer dial attachment, to prod for the golden bars in the mud and silt. Whenever the spear. POPULAR SCIENCE MONTHLY strikes a metal object, the clocklike dial aboard the salvaging ship Racer, indicates whether the spear point is touching gold or a base metal such as iron. The diver then receives his directions by telephone from the salvaging ship. The gold bars, as they are located, are raised in a tub. In this way nearly 3000 goid bars, worth from $5000 to $10,000 each, have _ been salvaged from the deep. ~ cate Baliey Mind Lich Re Con aie pT CT a ESTA nel ane Re Reali ee 2 ‘

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POPULAR SCIENCE MONTHLY His Hobby—a ‘Two-Mile “Vest Pocket” Railway How W. Cecil Gage ae a a hey Road from Odds and Ends By Raymond J. Brown G case years ago W. Cecil Gage, then an insurance broker in New York City, attempted to retire from busi- ness. He removed toa country estate at Fishkill, N. Y., and prepared to settle down to the life of a country gentleman. But his attempt to retire proved unsuccessful. Through an odd combination of cirecum- stances he has gone into the railroad business. He owns and operates probably the most re- markable railroad in the world —a complete miniature sys- tem, with two miles of track. And every inch of that track, every one of the nine pieces of rolling stock that pass over it, he built himself almost entirely from secondhand ma- terials. An Economical Road The gasoline motor that drives the locomotive, the car wheels—narrow-gage trucks of the type used for mine cars— and the strap-iron reinforce- ment on the wooden rails repre- Approaching one of the eight switches of the “Cecilwood Vest Pocket Railroad.” The rails are made from two-by-fours from a dismantled henhouse, while the ties are i from floor beams of the same building W. Cecil Gage at the throttle of his eight-horsepower gasoline locomotive, taking members of his family for an afternoon ride HERE was a time,’’ says Mr. Gage, ‘“‘when I wondered what value my friends could derive from their endless pursuit of golf, fishing, photography, working with tools—whatever it was they rode as a hobby. Now, though, I understand; for from my railroad—my first and only hobby—I have taken more enjoyment and valuable recre- ation than anything else ever has given me.”’ sent the only purchase Mr. Gage made in the construction of his railroad. Every- thing else—cars, rails, ties, switches, and the single trestle that bridges a brook— is made of discarded lumber and metal, picked up around the estate. Started as a convenience and pushed to completion as a hobby, the Gage narrow- gage road, which its owner calls the “Cecilwood Vest Pocket Railroad,” now is a commercial enterprise, paying sub- stantial dividends from passenger fares. At the same time it serves its original pur- pose of supplying a swift and convenient means of carrying farm products, fuel, and similar materials around the Gage estate. From every part of the country surround- ing Fishkill, by motor, foot, trolley, rail, and ferry, almost a constant stream of persons of all ages pours into Cecilwood to make the circuit of the big Gage farm in the tiny cars. Mr. Gage estimates this year’s mileage winter supply of firewood on midget flat cars record of his little road to be well above 10,000. The Vest Pocket Railroad owes its construction to the difficulty Mr. Gage encountered in dis- posing of the ashes from his household furnace during his first winter in Fish- kill, when he found it necessary to carry the ashes about a quarter of a mile to dump them. Although he never before had tried to build any- thing, he con- structed a little car, similar to a > Se ‘oe S KN To railroad flat car, in which to haul the ashes. Then, because uneven ground made the oper- ation of this car decidedly un- successful, he conceived the idea of running his car on rails. These rails he constructed of “‘two-by-fours” that had formed the framework of a dis- mantled henhouse, and he mounted them on ties sawed from the floor beams of the same structure. During that winter his ash car, which he pushed back and forth with a pole, did valiant service. Mean- while the ashes were utilized as ballast for the newly con- structed tracks. In the spring Mr. Gage extended his tracks another quarter mile or so and built a second car. Both of the original cars are still doing freight service. The necessity of conveying farm products, fodder and fuel $ te the various parts of the estate caused Mr. Gage to extend his ther until at last there was so much JC. B|_ STATION eters Here is a diagrammatic bird’s-eye view of the com- plete two-mile system of the “Cecilwood Vest Pocket Railroad” as planned and built by Mr. Gage. It in- cludes half a dozen stations, eight switches with signals, four grade crossings with warning signs; bridges, a ticket office, a turntable, a car barn and a roundhouse ‘made from a_ henhouse rail lines still far- at ER A PT aT poe C » a 4? POPTLAR SCIENCE MONTHLY ee ae ee ee ee

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witches of Railroad.” fours from he ties are > building vhich to because he oper- edly un- ved the on rails. structed at had of a dis- and he S sawed | of the ng that hich he ) with a ». Mean- utilized vly con- e spring s tracks r so and h of the 1 doing nveying and fuel of the sed Mr. tend his till far-" at last 30 much track that a locomotive was necessary. For a power plant for this locomotive, he bought an _ eight-horsepower gasoline motor of the type used to operate railroad hand cars. This proved successful in operation, and soon the task of extending and improving his little railroad became Mr. Gage’s absorbing hobby, occupying all his spare time. Little by little the road grew during the six years that followed, until now it has two miles of track, five passenger cars, two flat cars, a freight car, eight switches, four crossings, equipped with warning signs; a turntable, a snow plow, a ticket office and a half dozen stations. At night or during severe weather the rolling stock is run into a long chicken house, which serves as an adequate ‘‘roundhouse.” A Marvel of Amateur Workmanship The entire system is a marvel of careful, patient workmanship and ingenuity in utilizing waste materials. It is especially remarkable for the fact that it was con- ceived and built by a man who had no previous skill nor training in the uses of tools. Mr. Gage asserts that he never could have done the work for pay; with him it was a fascinating hobby—a labor of love—and in consequence it received his best efforts. Two of the cars are constructed of the wood formerly used to board up the win- dows and doors of the Gage home in New York while the family was away for the summer. The other cars were made of old doors, packing cases, and the partitions of demolished farm build- ings. Since Mr. Gage did not possess a ma- chine shop he had tc “7 call on a Fishkill garage and the local blacksmith for aid in gearing POPULAR SCIENCE MONTHLY Pe A weg Til wae (TT Mette NUS? Shee ===> = =4GRADE |= Z —~ 1CROSSING| Beginning with a quarter- mile line, over which he transported ashes from the cellar of his home, Mr. Gage gradually expanded his rail- road until today he has two miles of narrow-gage trac} ! fave - he Fa, * av = 5 Rae FH HEN HOUSE B 7 eS! ee the motor of his locomotive to the axle; but all the rest of his railroad Gage and his locomotive on the tiny “roundhouse” turntable. Note the automobile spotlight that serves as the rear light; also the pipe smokestack represents the work of his own hands, aided by an ordinary kit of car- penter’s tools.. The rails, 14 inches apart, are painted and tarred and protected on their inner top edges by strap iron. Except for the metal strip they are of wood. Comfort for the passengers is assured by elliptical springs on which the seats are mounted. The cars are about five feet long. Each is mounted on four eight-inch wheels, the axles being set close together to enable the cars to take curves without overturning. 41 HILL STATION — =~. SS SES ‘ PICNIC GROVE} Sse BRIDGE | ey Lt E TTLE BRIDGE STATION Although several thousand per- sons have made the trip around the Picturesque Gage property in the Vest Pocket Railroad, there never has been an accident. For a time Mr. Gage limited the list of his passengers to relatives and friends. The general public got its first chance to ride on the Vest Pocket Road at a church picnic held on the Gage property. After this the fame of the railway system spread so rapidly and so many persons appeared with requests for “rides,” that Mr. Gage decided to accommodate all comers who were willing to pay the tariff. Finds Happiness in His Hobby “It wasn’t the money I did it for,” he says, “but with my road earning a little, I felt sort of justified in spending all my time on something that was merely a hobby and plaything. My railroad is the first real hobby I have ever had. There was a time when I wondered what value my friends could derive from their endless pursuit of golf, fishing, photography, working with tools—whatever it was they rode as a hobby. Now, though, I under- stand; for from my railroad—my ‘only hobby—I have taken more happiness and enjoyment than anything else ever has given me.” So now the Vest Pocket Road runs on a definite schedule every day. And since Mr. Gage is at once engineer, conductor, passenger agent, traffic manager and re- pair crew, he asserts that the “retirement” which he went to Fishkill to find is largely figurative. Operating the train and keeping the system in repair engage him from morn- ing to night, seven days a week. He declares that he has less leisure time now, in his‘ “retirement,” than at any stage of his businees career. DDI AD CMIGAIS'R ASOOAIT LT V , . H } i | I it So SE eee ee areeeqenaet

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amTCL een aoe eee machen rons 42 POPULAR SCIENCE MONTHLY GIANT EXCAVATOR DIGS FROM ABOVE LY RN Pe RRS seers * Fr XTRSORDINARILY rapid excava- tion is accomplished by this giant dredging machine recently invented in Holland. Instead of working in the hole and passing up the diggings, as does a steam shovel, its scoops go down in an endless chain after the earth and bring it up, emptying it into waiting cars. METAL GARAGE WELDED TOGETHER Y THE ingenious use of old ma- terials, a novelty in building con- struction was effected in Miami, Fla., recently when a garage was built on a Unfinished building, showing tube frame HOUSEHOLD GARBAGE INCINERATOR HE malodorous and none too health- ful garbage can totters on its back- yard perch. No longer, it seems, need garbage accumulate to be carted to the public incinerator. A newly patented household incinerator consumes garbage in your kitchen as fast as it appears. This remarkable heater creates a temperature as high as 1200° F., suffi- cient to destroy ali combustible house- hold waste, wet or dry, animal or vege- table. This intense heat is made safe for the kitchen by insulation consisting of a thick asbestos lining and an air space between the outer and inner walls of the heater. After the garbage is burned, the residue is a small quantity of odorless and sanitary ash, which may be kept in the incinerator until enough has accumulated to justify emptying it. It is claimed that five cents’ worth of gas is sufficient to destroy a bushel of garbage, the time required being less than one hour. On the issue of economy alone, the invention is a success. framework of old boiler tubes electrically welded together. Not a bolt nor a rivet was used in the entire building. The roof of corrugated iron and the sheet-iron sides were welded to the skeleton. This building, which is 18 by 36 feet, is shown here while under con- struction. It is planned to erect a similar building 50 by 150 feet in ground dimensions. THE day is coming when diners will absorb electric vibrations instead of food, according to the prediction of Dr. Francis A. Cave of Boston, Mass. We'll eat our meals by attaching to our bodies apparatus connected with electric wires, he says. Intense heat burns up all garbage Soapstone Electric Iron Conserves Heat A NEW type of electric iron has been designed to conserve heat by taking advantage of the heat-storing qualities of soapstone, a substance once used for foot-warmers, bed-warmers, etc. The ironing surface of the invention is a relatively thin metal sole, surmounted ELECTRICAL CONNECTION PLUGS STUDSS,.- SOAPSTONE HEATING my, ELEMENT The iron with soapstone heating element by a soapstone block into which the heat is conducted. A close contact is meatless between the soapstone and the metal sole. To protect the housewife’s hand from burns, Insulation protects the housewife’s hand a layer of air is inserted between the cover and the soapstone, preventing excessive radiation of heat upward and sideways through the cover. It is claimed that after a seven-minute connection the plug may be removed and ironing continued for 45 minutes. Red Flags Do Not Anger Bull, Says Scientist Bue are color blind; therefore, wav- ing a red flag before a bull arouses no more anger in him than waving a pink, green, purple, or white flag. Such is the statement of Dr. G. M. Stratton, head of the Department of Psychology, University of California, after a six-month investigation of the sub- ject. When Doctor Stratton and his assis- tants waved red flagsin the faces of bulls and other animals, the reaction was one of curiosity only. He is positive the entire bovine family is devoid of color sight. S IF fulfilling Old Testa- ment prophecies, mod- ern science is preparing to harness the River Jordan to rejuvenate Palestine — the Land of Promise. This gi- gantic engineering project will be described dramatically in next month’s issue.

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"On » is been taking ualities sed for ition is ounted APSTON@ EATING ELEMENT? ment 1e heat etween e. To burns, hand en the renting rd and minute ed and iser t 2, Wav- arouses a pink, G. M. ent of fornia, he sub- iS assis- of bulls one of . entire rht. ta- od- to | to the gi- ect lly This vise stand is made port- able by collaps- ing the legs oe Portable Vise Stand Has Collapsible Legs HIS portable vise stand, designed to save steps for plumbers and steam- fitters handling lighter sizes of pipe, con- sists of a stout plank firmly supported by braced collapsible metal legs. The wide spread of the legs affords steadiness while cutting or threading pipe. A hinged pipe vise is attached to the plank. Four-Deck Stove Saves Heat Ds heat that usually is wasted up the chimney, a new type of stove permits gases formed in com- bustion to escape only after they have given up all their heat. After passing beneath the primary cooking surface the heated gases are circulated through a series of metal boxes, the tops of which serve as_ successive cooking surfaces. From the third box the gases pass up the chimney. POPULAR SCIENCE MONTHLY AIR GUN PASSES WHITE HOT RIVETS HE danger from white hot rivets, speeding from the tongs of the heater boy and sometimes eluding the bucket of the passer, has been eliminated by the perfection of a pneumatic rivet- passing system, in which the rivets are shot by com- pressed air to their destination through a flexible metal hose. Pneumatic pass- ers now in service can send rivets for a distance of 150 feet. The metal hose may bend around corners be- tween the passer and the discharge end without stop- ping the passage of the rivets. To start a rivet Above: Starting a rivet on its way through the metal tube. At right: The receiving terminal, showing how a cushion- ing disk receives the ‘ insured prompt The new four-deck . heating system ap- plied to cook-stove (above) and heater (at the left) on its way, the impact of the heater boy drops it upon a balanced check valve that allows it to fall into the admission end of the hose. Then, when he presses on a pedal, a blast of compressed air is re- leased from a reservoir, blowing the rivet swiftly to the other end of the hose. Meanwhile the quick expansion of air tends to cool the hose. rivet Reaching its destination, the rivet enters a receiving chamber, where a cushioning disk prevents it from being deformed by the sudden impact. Besides assuring safety for structural workers, the pneumatic system eliminates the usual waste of misdirected rivets that are seldom picked up and used. CABLE CARRIES MAIL ACROSS STREAM AN inventive farmer living in a rural district of California has delivery of his mail, at the same time performing a kindness to the letter carrier, by constructing the novel mailbox car- rier shown here. To reach his home, mail must be conveyed across a river 300 feet wide, and in times of high water the nearest crossing is more than a mile away. Cable lines and an old-fashioned bicycle wheel converted into a pulley, solved the problem. The mailbox is suspended from a carrier cable by means~of two small wheels attached to the top of the box. The lower part of the box is attached to a second cable running over the bicycle wheel pulley. Thus, when the operator turns the pedals of the wheel, the box is carried across stream along the top cable. After the mail carrier has deposited letters in the box, it is: hauled back, coming to rest inside a heavy strip of tire iron bent over a post: A fence prevents stray cattle from running into the cable lines. POPTIT AR COIBAISCER RAANAIT EY Vv At the left is shown the mailbox being conveyed across stream on carrier and pulley cables. Below: The pulley, made from an old- fashioned bicycle wheel, and the mail- box carrier system a“ HAT My Hobby Has Done for Me,”’ is the title of an unusual article by Arthur Stringer, popular American novelist, to appear in next month’s POPULAR SCIENCE MONTHLY. His hobby is—well, see the Janu- ary number.

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ployees of industrial and com- POPULAR SCIENCE MONTHLY Nine to One Your Eyesight Is Pulling You Back ‘By Guy A. Henry General Director, The Eyesight Conservation Council of America a book in the most interesting part of your evening’s reading because your eyes would not “carry’on,”’ you are one of the fortunatefew. Even so, the chances are at least nine to one that youhave defective eyesight. This statement may startle.you. You may ceny—probably indig- nantly—that you ever had any trouble with your eyes. You may say that they have always seemed ade- quate for your use. But, provided that you are more than 21 years of age, the chances are even greater than nine to one that some degree of trouble is there, whether you know of it or not. For it is only up to the age of 21 that this proportion holds true. Beyond that age, the prevalence of eye defects in- creases, until at the age of 40 scarcely a man or woman has perfect eyesight. But you needn’t be unduly alarmed. Science knows all about your difficulties, even if you are unaware of them yourself, and has provided ready relief in the shape of proper glasses. You I’ YOU never have had to lay aside That eyesight influences the efficiency of the mind has been determined by this test with the Galton Bar, a device that measures ability to perceive small differences in length While chatting with him I learned the reason for his ill humor. He had just had his eyes tested and had been informed that glasses would supply the only remedy for the headaches and fatigue that had been annoying him. “Glasses!” he growled to me. “I don’t need glasses any more than I need crutches! I’m not an old man—only 38. That eye man is an idiot!” My friend’s attitude is typical of that Even more numerous than those who know they should wear glasses and will not are those who are una- ware that they need glasses. A person whose eyes have been defective since early life is likely to remain ig- norant of the defect un- less he is informed of it. Accustomed to seeing things blurred and in- distinct, it never occurs to him that his visual pictures may be differ- ent from those of other people. Recently a man of about 35 told me that the best years of his life had been wasted as a result of his failure, through ignorance, to correct a defect in eyesight. As a schoolboy he had been “‘backward.”’ Later he had shown little aptitude for work, drifting from job to job until the war came and he was drafted. An army examiner discovered that he was suffering from a severe case of astigmia. Proper glasses were provided and he saw the world through different eyes. As a result, since this man’s discharge from the army he has become an expert machinist. He is making up the may not even need glasses. Probably a little rest for your eyes now and then and the cor- rection of some of your habits in reading or working may rid you of small defects that, while not warranting the wearing of glasses, may be responsible for head- aches and other disorders of a nervous character. Eye Strain Is Wasteful If your troubles are thus lightly corrected, you are to be congratulated. Statistics cover- ing a long period of years, borne out by a recent investigation among more than 10,000 em- mercial concerns, show indubit- ably that not less than 66 men and women out of every 100 you know are so crippled by defective How to Save Your Eyes ID you know that severe eye strain may cause you to use up fully half the vital force intended for all the organs of your body, draining the resources of your mind, your muscles and your nerves and producing severe fatigue? To avoid misuse of the eyes, with its consequent ill health, medical science offers these suggestions: Don’t read or work in insufficient light. well-illuminated places avoid the glare of lights shining directly into your eyes. Don’t read on street cars or buses. Rest your eyes at the first sign of fatigue. Be sure that your work is not at an uncomfort- able angle with the line of eyesight. Have your eyes examined by a competent prac- titioner for the correction of physical defects. Don’t refuse to wear glasses if you need them. deficiencies in his education by studying at night, and is slated for advancement by his employ- ers. All of this he might have accomplished years ago had any one discovered his handicap. Common Eye Troubles You may wonder why I lay stress on the use of glasses. I do so because they are the only sure means provided by science to aid the five common eye troubles In that are due entirely to physical defects in the structure of the eyes. These are: Far sight—caused by the eye- ball being too short. Near sight—caused by the eyeball being too long. Astigmia — caused by the transparent front of the eye curving more in one direction vision as to cause an appreciable economic waste. There is no physical defect that contributes more directly to inefficiency and is more responsible for waste of vitality, effort, time, and ma- terial than bad eyesight. Not long ago I met on the street a man whom I have known for years, an execu- tive of a large insurance company. Usu- ally good-natured and happy, that day he wore a black scowl and his greeting was anything but eordial. displayed by many persons in his position. They resent being told they need glasses. They feel they are being classified with the aged and the infirm. They fail to understand that glasses are the only means that science provides of correcting certain defects in the physical structure of the eye, from which many persons—be- tween 25 and 60 per cent, according to the findings of school examiners—suffer either early in life or later. ase pone seen than in another. Natural chanyes in the eye, occurring some time after 40 years of age, and usually necessitating the use of glasses for reading and other near work. Eye strain, resulting from the extra work that we compel our eyes to do in an effort to contend with insufficient and flickering light, glare and too long periods of near use without intervals of rest. These errors in many instances are serious, causing headache, eye ache, and -.~ Various nervous disturbantes.- Moreover, ~— i a

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1t se who ses and re una- glasses. 2s have e early nain ig- fect un- ed of it. ) seeing and in- r occurs $ visual e differ- of other man of me that ; of his asted as failure, lefect in ad been vn little b to job drafted. t he was stigmia. he saw ischarge 1 expert zg up the ition by is slated employ- ht have had any icap. ubles y I lay es. Ido nly sure ce to aid troubles physical 2 of the the eye- by the by the the eye direction the eye, 's of age, use of r work. he extra do in an ent and y periods ‘est. aces are che, and if the condition is permitted to endure for years, partial or total blindness may re- sult from cataract, a disease that authori- ties agree frequently is the direct result of continued eye strain in the earlier years. The abuse that the eyes of the average person receive has increased in the last couple of generations to a degree beyond estimation. Artificial illumination and the resulting pressure of modern commercial and industrial life are largely responsible for this increase. One naturally would suppose that modern improvements in artificial illumination would have made it somewhat easier for the eye to support its additional burden. But such is not the case. POPULAR SCIENCE MONTHLY XAMINATION of thousands of school children in the United States has revealed that between 25 and 60 per cent of the defective vision from which practically all of us suffer, comes during our schooldays, largely through faulty illumination. In the workshop, with its artificial illumination, 66 men and women out of every 100 are handicapped in their work by defective vision. Bad eyesight is directly responsible for enormous waste of energy, time, and material. Examine the two photographs below—one showing how a watch appears to normal eyes; the other, how it appears to defective eyes— and you will understand why many ' of us, accustonied from childhood to seeing things blurred and in- distinct, go through life in ignorance of the faulty vision. better than too little. Poor light will cause strain even to a normal eye, while there is little danger in over illumination, provided it is not accompanied by glare. The most common form of glare is that resulting from light shining directly into the eyes. Glare is the greatest danger of artificial light, and may be minimized by shades and the use of proper glassware to modify and ‘diffuse thelight. Barelightsshould not be tolerated. The slightest sign of fatigue, such as drowsiness or smarting of the eyes, is a warning for you to rest your eyes. That there is a definite connection be- tween the eyes and the stomach is in- dicated by the fact that The average eye has been un- able to keep pace with the demands resulting from the extraordinary development in such illumination of the last 25 years. It has resented the additional work that has been placed upon it, and the result has been disorders, many of which people do not attribute to their eyes. Conserve Your Eyes We cannot, of course, re- duce the speed and pressure of modern life even in defer- ence to so important a thing as our eyesight. There re- the nausea accompanying “car sickness” is attribut- able to the unnatural move- ments of the eyes caused by the vibrations of the car. In fact, general health and the eyes are closely associated. Defective eyes frequently are the cause of many disorders. Science Offers Hope Even though the eyes of most of us will not register ‘normal’ in examination, our plight is by no means hope- less. The human body always has managed to adjust itself to changing conditions of life. mains, then, only one thing to do—make the best of mod- ern conditions and learn how to use our eyes and not abuse and misuse them. The first thing I should ad- vise is periodic examination of the eyes by a competent refractionist — some one skilled in the science of mea- suring the human eye. Cer- tainly you should have your eyes examined if you have never done so, for you may be contending unaware with eye strain, near sight, far sight, or astigmia. But avoid those who offer treatment by mail. When using artificial light, see to it that the illumination is sufficient. What appar- ently is too much light is If one of these watches appears d'stinct, the other blurred, your eye- sight is normal. If both appear blurred, your eyesight is defective frie POPULAR SCIENCE MONTHLY eG Lf ,f The adjustment, though, re- quires time. We of this gen- eration are forced to bear the burden of a sudden change in our mode of life, caused by the demands of modern life and the recent development in the science of artificial illumination. That our eyes have not yet contrived to adapt themselves to the new . conditions is not remarkable. But they will—if given time. If people will take care of their eyes, use them and not misuse them, and exercise judgment and reasonable pre- ‘cautions, it is quite safe to predict that, despite the strain and pressure of our modern life, our eyes will not grow worse, but grow better. 47 Sg e| - mE eT ES SET oa Hi

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vWHA ua anes wa WRM HARE WH or The new safety system for bank vaults. Accidental locking of the door automatically summons aid. A tank supplies oxygen until rescuers arrive POPULAR SCIENCE MONTHLY If You Were Locked in a Bank Vault HAT if you were locked acciden- tally behind the thick walls of a steel bank vault? Can you im- agine the horror of shouting vainly for help; the agony of the long night hours of waiting, with hope ebbing and the torture of slow, suffocating death creeping upon light within the vault. This light illumi- nates a card on which are printed in- structions, at the same time revealing an oxygen tank close by. The accidental locking of the door also flashes an alarm signal, summoning police detectives. Acting on the printed instructions, the involuntary prisoner twists a stopcock on the oxygen tank, permitting the life- giving oxygen to escape into the vault ata pressure not exceeding 10 pounds. In very small vaults the prisoner puts on a mask connected with the tank; but in larger vaults the oxygen is allowed to you? The frequency, in recent months, of such tragedies with their untold mental and physical suffering, has led Alfred C. Bossom, a New York architect, to in- vent an automatic oxygen releasing device designed to save the victims of acci- dental imprisonment from suffocation. Mr. Bossom has supplied full specifica- tions of his invention to American. safety organiza- tions, and the first complete apparatus now is being in- stalled by an Ohio safe com- pany in the new building of the Texas Bank and Trust Company, Galveston, Tex. In the new safety system, dramatically pictured above by our artist, the locking of the vault door automati- cally switches on an electric HOW MANY OF THESE QUESTIONS CAN YOU ANSWER? VERY mail brings us scores of questions on mechanical and scientific subjects from Popu- LAR SCIENCE MonrTu ty readers. While the questions touch on every phase of science, mechanics, and natural history, there are numerous duplications and from those, as indicating the widest general in- terest, have been selected the following twelve. Our Information Editor has compiled thousands of answers to questions submitted by our readers. From these, other ‘“‘monthly dozens” will be pub- lished every month in Popuar SciENcE MonruLy. How many of these questions can you answer correctly? To test yourself, answer each one of them to the best of your ability. Then turn to page 139 and read the correct answers. See how near you can come to a -perfect score. You’ll find it an interesting game, and at the same time you'll be absorbing valuable knowledge. I. Are there any creatures that live forever? 8. Are modern men less healthy than pre- 2. Can submarines receive radio messages? historic men? 3. Why does soap help to remove dirt? 9. Where did the Red Indians come from? 4. What is the cause of earthquakes? 10. Why does food continue to cook after it is 5. Are there special brain foods? placed:in a fireless cooker? 6. Whyis Maine colder than France, although 11. What happens in your brain when you go about equidistant from the equator? to sleep? - 7. Why cana bird stand ona charged trolley 12. How strong must an electric current be to wire without getting a shock? cause death? escape directly into the room. A telephone permits the prisoner to commu- nicate with his rescuers. Asmall tank, it is claimed, will supply sufficient oxygen for the prisoner for at least 12 hours. Many recent instances of imprisonment in bank vaults have escaped public notice, according to Mr. Bossom, only because they have not resulted fatally. In nearly every one of these accidents the victim, when released, has been in a state of collapse after a night of terror. In one recent case, a young clerk who was locked in a trust company vault at Paterson, N. J., had torn his finger nails and bruised his body by beating on the thick walls of his chilled steel prison. POPULAR SCIENCE MONTHLY

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POPULAR SCIENCE MONTHLY “Flower Show” of the Deep bo eee fee a em SXWNAAQQAAQQ DHHEMMAMAARBI BWW Wy No more beautiful form of life is to be found than the Plumose Sea-Anemone, white, gray, or delicately pink. Scientists at the’ Heligo- land station say that specimens of this species floating to the surface have attracted even the bees with their flowerlike appearance The Sagartia, or Widowed Sea-Anemone (be- low), so called because it lives a solitary life, 2 ce : : resembles some exotic tropical plant. Its Here is a deep-sea taxi ride—a slow moving Sea-Anemone being beauty is a trap, for each of its delicate ten- transported on the back of the comparatively swift lobster tacles is a poisonous barb that seizes and stings to death any smaller creature within reach A’ THE bottom of the sea the plants it ————— are animals. Strange though this may seem, science proves it to be literally true. Vegetation is to be found only near the surface of the ocean. The flower-like life of its vast depth$, rivaling in beauty the choicest products of the greenhouses and cultivated gardens of the land, is animal life. The remarkable pictures on this page were photographed by scientists of the biological station at Heligoland. Ex- traordinary patience and skill were re- quired to get the subjects, in all their natural beauty, into shallow water where light could penetrate. WOM Y MMM oe 6 ig li This might be mis- taken for a beet, or . “4 At the left are two Sea-Cucumbers, possibly an_ onion. * among the strangest of all strange Actually, though, it is ‘ a “se : | ocean creatures. They are cousins a photograph of the es to the Starfish, shown here paying Compass Jellyfish, “ them a friendly visit, and to the with opalescent float- Se tree Sea-Urchin and the Sea-Apple. ing veils of unusual Chinese epicures frequently pay beauty and coloring high prices for Sea-Cucumbers Ce Sr RMI = ARAN ti SRN SB ARR NT PS PS: aM a S * POPULAR SCIENCE MONTHLY Their work showed a perfec- In ordinary photography—except in

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POPULAR SCIENCE MONTHLY Badect Actors in the Movies Camera Shows Wonders of Microscopic World By Louis H. Tolhurst MAGINE tossing a 120-ton locomo- tive up on your back and walking off with it! You could do it if you had the strength, in proportion to your size, possessed by the ant. This has been demonstrated in my work with insects incidental to photographing them for the screen. You have seen an ant crawling along the ground carrying a chip, breadcrumb, or some other burden that was a*dozen times its own bulk, and probably you have wondered just how much that ant could lift in comparison with yourself. I was interested in this, so I made an experi- ment. Coaxing an Ant I pent the better part of three days recently trying to coax an ant to move a fragment of match stick that would correspond in size to a telegraph pole for us. The ant paid no attention to me and I was about to give up when it easily picked up the stick and carried it away. This convinced me that the insect could lift a much heavier bur- den, so I fashioned a tiny telegraph pole, tied it in the middle with a piece of grass, suspended the ant from a loop of string and after repeated trials succeeded in induc- ing it to take hold of the grass bridle. The ant lifted the pole clear of the table with its mandibles—with its teeth! Con- sidering the weight of the ant, that pole represented a burden of 240,000 pounds, or 120 tons, for you or me! Consider a crew of workmen swarming over a building carrying a few bricks at a time, while puffing engines with der- ricks swing the heavy girders into place. Then consider ants of the stature of men, with their tremendous strength mag- nified in proportion to their increased size! The ants would have no need of derricks. They would handle steel girders as we handle toothpicks, each insect would be capable of carrying a carload of bricks up a ladder! Man’s prowess would be insignificant in com- parison. Wonders of the Insect World There is an old saying that the man who lives in the world of the telescope lives in a very small world, while he who lives in the world of the microscope lives * in a mighty, majestic world. Scientists who recently photographed the sun can attest to the first half of the saying and I am a firm believer in the latter half. For 10 years my work has

Shdéienatink insect ‘‘actors.” Louis H. Tolhurst, of Los Angeles, Calif., at work with the apparatus he has invented to make microscopic movies of insect life Here is

You have seen the house spider dangling at the end of his string, and probably you have observed how fast he ean move with it. I have spent hours watching spiders build their webs. One day I destroyed a web and the spider quickly rebuilt it. I did this again and again and the spider demonstrated he could spin almost as fast as I could destroy. His speed interested me so much I determined to find out just how fast he could work. In order to do this I rigged up a minute spinning wheel that could be turned as fast as the spider could produce his silk. Waiting until the spider emitted a tiny strand, I fastened it to the spinning wheel and started turning the crank. The faster I turned the faster the spider worked, until he reached the speed of 280 feet of silka minute. And two skeins of linen thread, about 600 yards in all, was once considered a good day’s work for a human operator at a spinning wheel! Then I watched bees building their yy

All photos courtesy Principal Pictures Corp. Highly magnified view of the dramatic in- sect movie photograph above, showing a common red ant lifting a miniature tele- phone pole with its mandibles. If a man had the same strength in proportion, he could lift a 240,000 - pound* locomotive consisted almost entirely of observing and photographing insects, first in still pictures and recently on motion-picture film, and the better I become acquainted with my insect subjects, the more I marvel at their wonders and capabilities. The strength of the ant was a revelation to me, but that was only one of the wonderful things I learned about insects. The spider, for example, demonstrated that as a spinner of silk he was much more pro- ficient than man with his old- fashioned spinning wheel.

POPULAR SCIENCE MONTHLY

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combs. Their work showed a perfec- tion undreamed of by human effi- ciency experts. Each bee knew exactly what to do and did it without waste motion. Scientists will tell you that the bee, in building the cells in his comb, uses angles that employ to the best possible advantage the amount of wax he has to work with. No mathematician ever has been able to improve these angles. Who knows but what the bee understands mathe- matics that would baffle even Einstein? The same holds for the common ant. Indeed, some scientists go so far as to place the ant next to man in intelligence. They point out the ant’s ability to build homes, to keep farms, cattle, slaves, and cows to be milked; to make war in well organized battle for- - mation; even to get drunk and dope itself with drugs. _Temperamental Insects While there is some doubt about any such intellectu- ality on the part of insects, there is no doubt they have one characteristic in com- mon with mankind. That is temperament; Human stars of the screen are proverbially ca- pricious. It is somewhat of a distinction, then, for me to be able to claim that I am producing pictures with a company of players that for whims, wilfulness, dis- inclination to work, and general ability to exasper- ate the director has no equal in the many studios of the great motion-picture industry. - You probably have seen spiders in the act of eating flies. I know I have. But when I wanted to film one in the act, I found myself up against it. I offered my spider fly after fly, but he would not eat. Spider Film Star Is Coy It took me nearly two weeks to coax him to eat. I believe he actually went hungry rather than do what I wanted him to do. And I spent nearly a week getting the spider to spin silk for me after I had built his spinning wheel. After the experiment was over, he POPULAR SCIENCE MONTHLY 49 In ordinary photography—except in very close work—a variation of a few inches, or even a few feet, will not throw the subject badly out of focus. But when the subject is invisible to the eye and must be magnified thousands of times in order to be photographed, you can see that a movement measured in thousandth parts of an inch would be sufficient to destroy sharp focus. On this account it was necessary for me to develop a lens capable of 100 variations of focus within the thickness of a human hair. This may seem almost incredible. Consider, though, that in photographing the micro- scopic life in a drop of water confined between two glass plates, the distance between the two plates of glass is microscopically so great that the swimming organisms farthest away from the lens are actually out of focus! Using Heatless Light Correct lighting, too, fur- nished a problem, for light from ordinary sources suf- ficient to illuminate my “scenes” contains enough heat to kill my actors. So it was necessary for me to develop a virtually heatless light. I do not claim, of course, to be the only in- ventor of heatless light, but my method is the only one that I have found satisfactory for microscopic motion photography. The ferocious looking house spider above demonstrated that as a spinner of silk it is more proficient than man. The lower photograph shows the spider feeding a tiny spinning wheel at the rate of 280 feet of silk a minute! animals can be. Special apparatus is re- quired for the work, and, since suitable apparatus was not available, I had to develop it myself. Probably the only part of my equip- ment that would be at all familiar to any one versed in motion-picture pro- duction is my camera. That is an or- dinary studio model, although it is mounted on a permanent platform and the film is turned by an electric motor, somewhat after the fashion of the cameras used for making film titles. The rest of the apparatus is especially de- signed for my needs. I cannot claim to have made any discoveries in entomology as a result of my motion-picture work. But my camera has enabled me to bring to the eyes of every one the absorbing events of the kingdom of insects that heretofore scientists alone have been able to view. Parasites in the Ant’s Eye I have made one-reel pictures of the bee, spider, and ant; but so far have scratched only the surface. In studying the ants I found that in some cases they have parasites on their eyes, tiny organ- isms living in their own tiny world. Such revelations make me wonder whether there is any limit to the built webs all over the studio. As I said before, it took me three days to induce an ant to pick up a bit of matchwood, but when I threw such a stick into a hill of ants on which the camera was not focused, they fought to carry it off. Of course, tiny crea- tures such as the mem- bers of my picture com- pany cannot be set up and. photographed as human actors or large HINK of an ant the size of a man and with the strength to lift 240,000 pounds and you have some comprehension of the fascinating interest which Mr. Tolhurst finds in his daily work. eye! Educated for the bar, this young California scien- tist has brought science to motion pictures and the wonders of insect life, hitherto to be observed only under microscopes, before the eyes of every one. Read his story of the strange things seen in the world of the infinitely small. You wonder how man became the dominant creature in the world! nicety of nature’s work. First the tiny ant, then its smaller eye and then complicated little mites with eyes of their own living and dying in that And who can say that science will not dis- cover even smaller crea- tures living in the eyes of these parasites? The lives of the in- sects are full of mystery, charm, and human ap- peal. No one will ever exhaust their interesting possibilities. QO ncn ctin totic.” ee LEE toyrieay A nae — pained! POPULAR SCIENCE MONTHLY EE ee eee I SE aaa NS aaa a i in - iriemenaee is res 5 = = = CS eee a a a eR a eR Re gg ten tle aap ata min Sa reat ee us Lee ey ES recharge areal ee a en Stes ee ; ~aegueneee

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POPULAR SCIENCE MONTHLY

eres the resistance of plate glass by means of an artificial 125-mile gale created by the whirring propeller of a motionless airplane was the feat per- formed recently at the Curtiss Flying Field, Pine Valley, N. J. An SE-5 plane, equipped with a 220-horsepower motor, was used. A sheet of plate glass five by six feet

and one quarter inch thick was placed directly behind the tail of the machine in such a way that the blast developed by the propeller would be directed against it with the least possible diffusion. The glass showed no trace of injury after the test. The velocity of the gale was mea- sured by calculations involving motor revolutions, propeller pitch, and slippage. A Disappearing Fan for the Home

The fan blades extended for use

A™ ELECTRIC fan, the blades of which disappear into an electric- light chandelier when not in operation, is the invention of Clarence W. LeVelle of Wichita, Kans. The fan is formed of curved blades pivotally attached to a rotating plate concealed behind the casing of the chandelier. From the casing lamps are suspended in artistic arrangement. When not in use, the fan blades. are swung back by spring controls into a con- cealed position.

Fingernails Grow 27 Yards ROM a Swiss scientist comes an an- nouncement that the average man of 50 has 27 yards of fingernails in his life- time. He says that children’s nails grow faster than those of adults; thumbnails faster than little fingernails. Fire Pump Driven by Ford Engine A SMALL, portable pump attachment for Ford cars, driven by the auto- mobile engine, recently has been per- fected for use in pump and attachments requires about an hour and a half. Thereafter it may be connected or disconnected in two minutes.

Simple Spool Device Aids in Developing Photos ACILITATING the work of the ama- teur or professional photographer, this simple film-developing device con- sists chiefly of two spools, mounted on spindles. Each spindle is attached to a vertical support, and the film to be de- veloped is carried on the two spools.

BE LIP es

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< Developing a roll of films held on spools The upper spindle has a handle so that the film may be revolved. The vertical support is vertically adjustable, so that a film strip of any length can be accommo- dated. A semi-cylindrical basin just under the bottom spool contains the de- veloper or other solutions, so that the revolving film passes through it. Thus the operator can stand in a practi- cally erect position while handling film.

construction and road work, fire protection, and ir- rigation. When the engine is running at a speed of 18 miles an hour, the pump is said to have a capacity of dis- charging from 200 to 250 gallons of water a minute at a pressure of 20 pounds. It will lift water by suc- tion to a height of 26 feet. The first installation of the a en

52 An auto, with pump attachment, lifting a stream of water

i a Rs i

Family Strong Box Has Combination Lock PREG fingers cannot disturb valu- able documents if they are locked in this fire- and burglar-proof safety box recently designed especially for family use by a manufacturer in Fulten, Ill. The box has a special combination lock, with dial control.

New Gum for Varnishes “¢@NUAPINOLE” is a tree from which a new gum is taken in Mexico. It is reported to be of such quality that it may be used in making the finest varnishes.

POPULAR SCIENCE MONTHLY

Twin "Twnewritere Decode Maccadgec | aE : al

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spools > that ortical that a mmo- just he de- at the oracti- y film.

valu- ked in y box ily use nation 1eS hich a It is it may hes.

Umbrellas Tested by Wind

@o ££ Gs teaon Fas. ten: 296s. Support with Basin Keeps Christmas Tree Fresh HIS Christmas-tree support fits any tree, preserves it from withering, and restricts its tendency to shed needles. It will hold a tree weighing 250 pounds, it is claimed. The four legs of the device, spreading enough to al- low a container of water to stand between them, raise the tree several inches from the floor. Thus, although the base of the tree extends into the water, it does not rest on the dish. This supply of water keeps the tree fresh. A wingnut adjusts the holder to the size of the tree butt, and holds the tree securely. Screw holes in the legs permit fastening them to the tree. When not in use, the holder folds into a small, compact shape.

The air-pressure rifle High-Pressure Air Rifle for Marksmen gel marksman can practise with a new high-pressure air rifle recently put on the market. It has the full range and penetration of a high-powered fire- arm. The rifle is 22 caliber and will kill all sorts of small game at 100 feet. A plunger rod with a button that pro- trudes from the end of the gun, works back and forth in the gun barrel. Air is compressed in a chamber by placing the muzzle of the gun on the floor, holding the plunger rod button firmly between the soles of one’s shoes, lifting the gun until the rod is out full length, and then bearing directly down. The number of strokes pumped in the gun determines the force of the shot. Inexpensive pellets are used as am- munition. There is nothing in the gun to wear out and the only care necessary is an occasional oiling. POPULAR SCIENCE MONTHLY

51

E. S. Wilson, government chemist, with 38 samples of heutlos liquor under test Peril in Bootleg Poison Revealed EN to one odds against the man who patronizes the bootlegger were re- vealed recently when 38 samples of illicitly sold liquor, bought in 15 cities, were analyzed by Government chemists at Washington, D. C. Portable Welding Outfit Carried like Knapsack N OXYHYDROGEN burning and welding apparatus that can be carried on the back of a workman like a knapsack has been invented in Germany. Heretofore it has been necessary to use two heavy steel tanks and long hose to convey the gases to places difficult of access. Sometimes the hose has been cut in confined spaces with serious results to the workmen. The new outfit consists of two small steel tanks, one containing liquid oxygea; the other, liquid hydrogen. Pressure of the gases is controlled by valves. A third control regulates the mixture of the two gases for the flame. Only two of the 38 proved to be whisky of pre-prohibition grade. One was pur- chased in Boston and one in Washington, D. C. Two were passable synthetic gin, from Cleveland and Los Angeles. The remaining 34 samples were poisonous.

England Has Snauie Plane Carrier HE first vessel in the world especially designed as a ficating landing field and airplane carrier, the Hermes, was put through protracted and comprehensive tests by the British Admiralty. The carrier is capable of a speed of 25 knots. In the body of the Hermes are two hangars with room for 20 planes. The funnel, observation tower, wireless apparatus, and operating quarters all are placed far up in the bow, allowing for a spacious flying deck extending more than three fourths the length of the vessel. Planes are elevated from their hangars to the flying deck by electric lifts and cranes.

The ne shiphains siguusbell Hermes, showineigdhtous landing field shad ye

a <i as pees onl eet Por Naa a ee tances cr ce asl censaitine eS a re ee eaetant permeate appaneiioesstt 5 lta eget oe i ct pea gene Sy : if | { | | i / ? see sates

POPULAR SCIENCE MONTHLY

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52 POPULAR SCIENCE MONTHLY Twin Typewriters Decode Messages B*. A simple ad- justment, a message typed on one of these type- writers can be made to appear on a sheet of paper in the opposite type- writer in any one of 280 codes. Similarly, a mes- sage in any one of these 280 codes can, by the same sort of adjustment, be decoded on a sheet of paper in the other type- writer. The ma- chines can be x me Pa operated long The remarkable typewriters are joined > a network of wires distances apart. This Shaving Brush Will Soap Itself ORKING on the principle of the fountain pen, this remarkable new fountain shaving brush can be filled with an ever-ready supply of shaving cream. When nct in use the brush is inclosed ia a removable cover that protects the bristles. The brush may be regulated so that any desired quantity of soap or cream is forced into the bristles when required. This is accomplished by aa ingenious plunger arrangement. This feature elimi- nates waste of shaving cream. The~ brush reservoir holds enough shaving cream for more than 70 shaves. When the brush has , been charged with ae shaving cream, the bristles are dipped : i into water and the ear dae \ { soap solution is then BRUSH HOLDER SOAP HOLDER ——_ worked up on the N AUTOMATIC washing and steril- face as with the ordi- - izing machine for glassware, for use nary brush. Filling the fountain brush. The parts are shown in inset in restaurants, is electrically operated. Its capacity is 700 glasses an hour. The glasses are conveyed by a circular New Tractor Wheels Protect Roads _ motion to a cold-water spray to remove refuse, then to a hot alkali wash for A TRACTOR grip cleansing, then to another cold spray to wheel, which is remove excess alkali, then to a sterilizing said not to injure solution that destroys bacteria, and roads, has been in- finally to an electrically heated hot-water vented by Calvinand rinse that assists the drying. The glasses Nelson Davey, of require no handling once they are placed South Vienna, Ohio, on the tray of the sterilizer. and .was_ recently seinen successfully demon- strated by them. Anarrowsteel band exactly as high as the grip bands edges the inner and outer cir- cumferences of each wheel. When the wheel operates in a field, these edging bands sink into the earth and permit the grip bands to come into use. On a hard road the edging bands : = =i keep the grip bands : The new tractor wheel Godinaty cheated wheel from making traction. This machine washes 700 » Nei comer Twin ont Takes Movies and Stills at Once A otion pictures and still pictures can be taken simultaneously, and focused by one finder with this Siamese- twin camera. Above is shown Frank S. Wilton, of Huntington Park, Calif., in- ventor of the camera, with which he photographed a large part of the film, “Hunting Big Game in Africa.” The motion picture part of the camera is fitted with four lenses, including a tele- photo lens for taking close-ups of wild game. Electric Machine Washes Glasses Automatically nmRrmmMmrTrrTrAar Oo Trearcrn -asceaarrewrre =e

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shes lly _ steril- for use erated. circular remove ish for vray to rilizing 1, and t-water glasses placed burly Umbrellas Tested by Wind from Airplane Propeller O MAKE sure his umbrellas would not be turned inside out in any ordinary storm, an inventive umbrella manufacturer decided to subject them to airplane wind tests, which are the severest wind tests known. An open umbrella, held before a seven- foot tunnel through which the wind was drawn by a 420-horsepower Liberty motor, withstood a wind strain of 34 miles an hour before collapsing. As the umbrella was subjected to the full force of the air current, it was stated that in actual use it might stand an even greater wind. At the velocity of 34 miles an hour the operator had difficulty in holding it. The manufacturer claims to have been able to ner the strongest umbrella known. Testing an umbrella in wind tube ‘‘Murder-Tree’’ from Brazil VERITABLE “murder tree”’ called clusia—an ogre from the tropical forests of Brazil—is a new attraction at Kew Gardens, London, England. With aerial roots it strangles every tree near. Birds deposit the clusia seeds on branches of neighboring trees. From the seed, roots grow toward earth, throwing out branches that envelop their victim. POPULAR SCIENCE MONTHLY oan ee nth er ercks " The river dredge and its Diesel engine First Diesel-Electric Dredge Economizes Fuel ESS than half the normal amount of fuel is said to be necessary for the operation of a new dredge at work in the Columbia River at Longview, Wash.— the first pipe-line dredge in the world to be operated by Diesel-electric power. Fifteen barrels of fuel oil are required in 24 hours to operate the 525-horsepower Diesel engine, which in turn runs an electric generator to drive the electric ma- chinery of the dredge. A steam-power dredge of approximately the same power and capacity requires 40 barrels of oil a day for her furnaces. At present prices this is said to represent a saving of more than $50 a day. The dredge was designed specially for shallow digging by James H. Polhemus, general manager and chief engineer of the port of Portland, Ore. It is capable of moving 225 yards of material through a 15-inch pipe-line in an hour. It is the smallest of a number of dredges engaged on a lumber mill and town site project, in which more than 12,000,000 yards of material will be moved. On such a huge project the saving that the Diesel-electric engine is said to effect will be considerable. Safety Bumper Has Canvas Stretchers NJURY to a pedestrian struck by an auto ~ equipped with this automatic safety bumper is practi- cally impossible. Contact with the pliable front guard rail of the auto- mobile causes two arms to spring out and draw the per- son struck on to two canvas stretchers, so de- signed as to pre- vent sharp contact with any part of the car. Sunder arms craw the pedestrian onto the canvas stretchers 3] og RE \. / Portable Electric Hoist Saves Manual Labor A PORTABLE and easily operated electric hoist, that permits one man to do the work of several, has been per- fected by a Philadelphia concern for shops Hoist is ccusiaieh with one Sete and factories where bulky materials and machinery must be moved quickly and often. The device consists. of a standardized chain hoist of steel, electrified by a heavy- duty motor, which may be adapted also to standard chain hoists already in service. A hanging controller is operated by one hand, leaving the other hand free. to guide the load. Where current is not available, or if the power fails, the hoist may be operated by hand as an ordinary block. : POPULAR SCIENCE MONTHLY

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SE Power from th POPULAR SCIENCE MONTHLY dreamed of turning to practical use the elec- tricity that now is consumed by destructive lightning bolts. M. Jules Guillot, a French inventor, has _ per- fected a machine to utilize . this latent power. He bases his experiments on the theories of static electricity proved by such scientists as Franklin, Lord Kelvin, and others. Accord- ing to these theories, static is produced by the motion of the earth around its axis through the non-conducting ether. This motion causes the earth itself to become charged negatively, while the air around it is charged both negatively and positively. Since like charges repel each other and unlike charges attract each other, the atmosphere’s negative charges are thrown away from the earth’s surface while the atmosphere remains as a _ positively charged blanket. The difference of potential between the positively charged air and the negatively GS areamed of long have ZA8 e Sky May Light Our Homes charged earth constitutes an unused source of electric energy. Since the amount of this difference depends on the distance from the earth of gas particles forming the atmosphere, Guillot has es- tablished his experiment station upon the summit of Mont Blanc in Switzerland. At the station there are two antennae, The complicated apparatus used by M. Jules Guillot at the summit of Mont Blanc, Switzerland, to draw power from the air a one extending toward the f equator, the region of max- imum density of the positive charges; the other consisting of a number of iron points extending vertically upward. The positive ions are at- tracted by the antennae pointing south and build up a charge upon a plate in the machine. A second plate is connected with the vertical antennae. Because of the difference of potential, this second plate absorbs a certain amount of negative ions that ordinarily would be repelled from the earth. Thus it is ence of potential or volt- age within the machine that will cause a current to flow from one to the other when they are short circuited. Instead of trying to use the voltage for this purpose directly, the charges are led off through step-down transformers. It is claimed by the inventor that in this way he has been able to keep ten 50-watt lamps burning, utilizing only the static electricity of the air. Measuring Flowing Quality of Oil Tits measurement of viscosity, or fluidity—that property of lubricat- ing oils having to do with their resistance to flow—always has been a troublesome one to engineers. The most widely used instruments for measuring viscosity have been suited only to labo- ratory use and the involved computations necessitated have made them highly unsatisfactory. Now, however, comes an extremely simple instrument that is said to de- termine fluidity far more accurately than The new measuring outfit any device so far invented. It consists of a cup of steel or cast iron, provided with a hollow stem that forms a thermometer pocket extending into the metal of the cup. A steel ball fits into the cup. The concave surface of the cup has three minute projections that prevent the ball from making complete contact and also regulates the thickness of the film of fluid under test. In taking a measurement of the fluidity of an oil, the steel ball is dropped into the oil and picked up by pressing the The time it takes for the oiled ball to fall from the cup measures fluidity of oil cup on it. Fluidity at the temperature registered by the thermometer in the handle is determined by the length of time required by the ball to fall. Formerly viscosity was measured by the length of time required by a certain volume of oil to flow through a tube. BLUE-EYED men make the most bull’s- eyes, according to United States Army statistics, which show that of 1000 men qualifying in military marksmanship, 605.41 have blue eyes and 394.59 brown. POPULAR SCIENCE MONTHLY He Studies Microscopic Life in Yellowstone Geysers Te sort of life that may have swarmed in primordial seas is being studied in the hot springs and geysers of Yellowstone Park with an extraordinary combination of high-power microscope and motion-picture camera. Most scientists believe that, when geologic time was young, the earth’s crust and its waters were extremely warm. They believe that only special forms of life could exist in those ancient seas. The present studies, under the supervision of Dr. R. B. Harvey of the University of Minnesota, shown above, seek to de- termine whether the microscopic creatures in Yellowstone’s hot waters are similar to those ancient creatures, and to learn, if possible, the biologic secret of their heat enduraace. possible to establish a differ- | c+ oq -™~ het DO oes et Oct OD ODD UTS ee a a er

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1eS ird the of max- positive nsisting | points ipward. are at- ntennae yuild up late in nd plate vertical of the al, this . certain ons that repelled ius it is a differ- r volt- ne that to flow er when tage for ; are led formers. that in eep ten 1g only c Life ers y have is being ysers of ordinary croscope » When h’s crust > ‘warm. ‘orms of as. The rision of arsity of to de- reatures . similar to learn, of their

Engine Crews Endangered by Gas in Tunnels N ARTICLE in the September issue of POPULAR SCIENCE MONTHLY called attention to the danger to public health in carbon monoxid gas from the exhaust pipes of automobiles. Now the Depart- ment of the Interior, after an extensive investigation, has reported another grave menace—the possible asphyxiation of locomotive crews by the same poisonous

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Poisonous carbon monoxid gas from engine stacks endanger the crews gas from the engine stacks while passing through long tunnels. The most satisfactory solution of the problem, according to experts, is to supply air to the engine crew through respirators attached to the air-brake pipe line of the train. These respirators consist of fun- nels connected with the pipe lines by rub- ber tubes and held by members of the engine crew near their faces. Valves con- trolled from the engine cab regulate the flow of air for normal breathing. The pipe lines supply pure air for 30 minutes. Electrical Bath Cure LECTRIC baths are made possible by a novel electro- therapeutic appa- ratus developed by two physicians of Newark, N.J. The patient is placed within a magnetic field in a cabinet, where he may be sweated, baked, or bathed with elec- tric light, accord- ing to the treat- ment his ailment requires. At no time is he in con- tact witha primary electric circuit, as only induced cur- rent is used. _ new cloth is said to cost far POPULAR SCIENCE MONTHLY -

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U. S. Has School for Hay Inspectors A TRAINING school for Federal hay inspectors, the only institution of its sort in the world, has been opened in Au- burn, N. Y., under the direction of the U.S. Department of Agriculture. Completing their training, these in- Grass Fabric Made by Bacteria ITH bacteria for assis- tants, Jonas Brolin, a textile engineer of Oakland, Calif., is said to have man- ufactured a fabric as fine as linen from China grass. The less than those for which it is a substitute. The grass is soaked in tanks of water over which are spread bacteria that re- produce with astonishing rapidity. A cubic inch of water is said to contain 2,000,000,000 of them soon after they are introduced. The bacteria attack the gum and resin on the grass fiber. When the gum has been separated from the fibers, the grass is removed from the tanks and dried. A machine next softens and subdivides the fibers, pre- paratory to the spinnirig and weaving. These final processes use regular cotton- manufacturing machinery.

spectors are distributed throughout the hay producing sections of the country, to issue certificates upon hay that meets Federal standards. The men are shown above at work in the school grading hay according to the government standard.

Above: Sam- ples of the new *finen’’ fabric, pre- pared by bacteria. At the right: A bale of China grass from which the fabric is woven

Snowflakes as Patterns OOK at your necktie and see if it has an unusual design. Perhaps that design was suggested by a snowflake. “Snowflakes are used by silk manufacturers extensively as patterns,’ says Wilson A, Bentley, speaking of his article for next month’s POPULAR SCIENCE MONTHLY. “‘Jewel- ers fashion delicate designs from ideas they get from snow- flakes. Even biscuit makers transfer Nature’s handiwork to their cookies.” Mr. Bentley’s is a remark- able story of a farmer whose fascinating hobby made him famous. It is full of the won- der and romance of science.

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POPULAR SCIENCE MONTHLY

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2 ‘ 2 een ane POPULAR SCIENCE MONTHLY Evolution—A Universal Law Concluding Article in “The Story of Man and His World”’ By E. E. Free, Ph.D. HE subject of evolution is like this round ball that we live on and call the earth—it is so vast that no man can see more than a little of it at once. To any single human eye the earth seems nothing but a broad, flat plain more or less wrinkled with moun- tains and_ scratched here and there with lakes or rivers. A Limited View Similarly, it seems to many people that the theory of evolution means merely an idea of the bodily origin of man; that it is the story of how this won- derful body of ours has been developed in the course of millions of years out of simpler and more _ primitive kinds of creatures. This really is, of course, one of the things that evolution means. It is the story of the evolution of man that we have been telling, in the main, in the pre- vious chapters of this serial. But this is only a very small part of what is included and implied in the idea of evolution. The whole theory of evo- lution is as much more than man as the whole earth is more than your dooryard. It is probably the grandest and most far reaching idea ever grasped by the human mind. The idea of evolution may be defined, as I have explained in a previous chapter, as the idea of change. Things alter as time goes on and become new things. The unending panorama of growth and alteration is the universal law of life. All Things Change Continually Unliving as well as living things change. The earth changes. Mountains are worn down. Rivers alter their courses. The oceans advance and retreat. Ice sheets spread and disappear. The eternal hills are not eternal. The fixed stars are not fixed. Everything in the universe—man and man’s ideas, the world he lives on, the sun that warms him, the stars that he looks up to and wonders at in the sky, even the chemical elements that make up the machine that man calls his body; each and every one is in continual change. “Permanent” things seem permanent to us only because we live so short a time. If a lifetime were a billion years, we should see the mountains melting before our eyes, the stars racing across the sky, the earth heaving and wrinkling under us. 58 Seashell Makes Effective HOW INVENTIONS EVOLVE The first typewriter of 50 years ago would be unrecognizable today. The telephone, the dictation phonograph, the bookkeeping machine and other results of scientific evolution have transformed the modern office This is the greater theory of evolution, the theory that not man alone, nor living matter alone, but everything is chang- ing, moving, producing something new. Everything everywhere evolves. Let us take a familiar example—the evolution of inventions. Many people remember the first telephones; a few re- member the first typewriters; - nearly all of us remember the first automobiles or the first airplane, with the Wright Brothers riding out in front of it on a little board, like some one perched precariously on a window- sill. Compare these recol- lections with present-day realities. Inventions, ma- chines, human: devices of all kinds obey the universal law. Not even so simple and satisfactory a thing | as the buttons on your coat remain the same for 10 years in succes- sion. This is evolution. Think of the history of transportation. The first men were their own wag- ons; when something had to be moved, they carried it themselves. Then some one learned how to catch wild oxen and make them into beasts of burden so that one man, using his brain to direct the muscles of his ox, could carry more weight and could take it farther in a day. Soon some other genius invented a drag of poles to slide along behind the ox and still more weight became trans- portable. Finally, men learned how to make wheels and wagons that rested on them and how to catch horses that could move faster than oxen and go farth- erin a day. And today we have tamed gasoline to replace the horses on the highways and steam to_ transport things still longer dis- tances over rails. Life's Inventions What is this but evo- lution? The ancient slime specks, you re- member, at first were not able to move them- selves about at all. Then presently they invented muscle fibers so that they could twist themselves through the water. Next they invented a stiff rod down the back so that the muscles could twist them more violently and move them faster. They then began to swim like a fish. Gradually, invention by in- vention, they moved ashore and learned to creep and to walk. Some of them have even learned to fly. How similar this is to the history of the human inventions that have given us our present means of transportation. This universality of evolution is evident in every human activity. We can trace, for example, the history of the cultivation of the soil, step by step, from the most ancient way of stirring it with a forked stick down to the latest modern cultiva- tors that pull a score of plows by gasoline. Ceocaay U.S. Radium Co. RADIUM EVOLVES—How radium is prepared for many uses, including illumination of familiar radium watch figures (inset)

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W in a day. er genius z of poles r behind till more e trans- ally, men to make yons that em and h horses ve faster go farth- nd today 1 gasoline horses on ys and transport nger dis- ils. ontions ; but evo- e ancient you re- first were ove them- at all. tly they scle fibers yuld twist ough the 7 invented ie back so. uld twist ind move n to swim on by in- id learned chem have sory of the ven us our mn. is evident can trace, -ultivation . the most 1 a forked rn cultiva- y gasoline. . S. Radium Co. many uses, res (inset) We can trace weapons of warfare in un- broken sequence from the hurled stone or swung club of the caveman to the poison gas and airplane bombs of modern destructive science. Even cookery is a traceable evolution from the ancient hot stone dropped into the stew with the bones. Fountain pens and fluid ink are direct descendants of the earth-smeared thumb of the prehistoric cave painter. We still have two buttons on the backs of evening coats because men used to wear a sword belt that had to be held up behind; an evolutionary vestige this, quite com- parable with the fact that we still have an appendix inside the human body. Ideas Are Subject to Change Nor is invention the only place where evolution is evident. Ideas, too, ure sub- ject to evolutionary change. Think, for example, of what men believed from age to age about the place and support of the earth in space. In the beginning they thought it was a flat thing like a saucer floating in a universal sea of water. A few people, more curious or imaginative than the rest, asked themselves what the water was resting on and found no answer except the mythical ones of a great ele- phant or a broadbacked turtle or some gigantic strong man like Atlas. On some creature like this the whole universe that we know was supposed to rest. But as time went on, these ideas changed. Men perceived that the earth was really a round ball, the center of the universe. The heavens revolved around it. Then ideas changed again. We believe now that the earth, far from being the center and focus of everything, is but a tiny speck revolving around a mighty sun which is itself a mere speck in the inconceivable vastness of space. And that the evo- lution of these ideas is still going on, that what we think about space and about the nature of the universe is about to change again, is evidenced by the theories of Professor Einstein with which the scientists are now so much concerned. Other examples of the evolution of ideas are visible in those that we call social customs. Consider table manners, for ex- ample. The cave man merely grabbed what he wanted, dipping his hairy fingers in the pot or snatching bones out of the fire. Even so recently as three or four centuries ago most of our ancestors ate from a common dish, slicing off with daggers such morsels of meat as struck their fancy. Evolution has been much at work since then, and lest you ae 0.8" ae 8 ae THE EVOLUTION OF shee... ll is ctrikingly illustrated by this comparison of the ancient ox cart with the modern motor truck ees ~ POPULAR SCIENCE MONTHLY 57 think these matters of social custom un- important in world history, remember that few crimes are punished so unfail- ingly or promptly, either by business or by society, as crimes against custom, the crimes, for example, of guzzling coffee from a saucer or of eating with your knife. It is not in the least an exaggeration to say that if one is unable to acquire such table manners as one’s social surroundings demand, this may be an even larger factor in the prosperity of the individual and in the survival of his offspring than was a weak backbone to a creature in the stage of evolution between the worm and fish or am un- sure eye to the monkey who was on the way toward an ape. It is quite pos- sible that the scientists of 10,000 or 20,000 years i eee a. IF YOU COULD LIVE A MILLION YEARS you would see this mountain melt away under the rains and snows of the centuries. Not only the very earth itself, but our uses of its natural forces, are in evolution. Compare the modern wonders of electricity with Benjamin Franklin’s kite that pulled electricity from the clouds, paving the way for a new age of scientific marvels from now, when they come to look back on the 10 centuries of the millennium in which we are now living, will hold its most important evolutionary event to have been the growth of those social ideas and customs that scientifically we describe as humanitarianism but which find their real and everyday expression in what we call politeness. (Continued on page 140) Beginning Next Month The Story of the Mind Most fascinating and useful psychological series ever published in a magazine By James J. Walsh, M.D. Famous American surgeon and psychologist Read his preface on page 34 of this issue oD eee ot a aa an pe ms aaa pa a iP ESE aT POPULAR SCIENCE MONTHLY Tiunins C\eile... sien Nlarve Cantare 59

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een 58 Seashell Makes Effective Loudspeaker Horn peony emg of radio apparatus, seek- ing a form of loudspeaker horn that would be small, ornamental, and at the same time produce a large volume of sound, are said tohavereceived valuable sug- gestions from the accidental use of a seashell as a horn by a radio enthusi- ast in Atlantic City, N. J. Desiring a loudspeaker for his portable set, but finding the horn too bulky, he attached the shell to the loudspeaking telephone and was astonished by the result. Although the shell was only a few inches long, its peculiar shape gave it acoustic properties that caused it to produce as loud and perfect tones as had been obtained from a larger horn. Remedies Inaccuracies of Variable Condenser Egaere inaccuracy in the spacing of the plates common to many of the pres- ent forms of variable condensers has been remedied by one manufacturer by making the spacing collars of the condensers an integral part of the condenser plates. By this form of construction accurate as- sembly and rigidity are assured. How to Avoid Grounding of Your Aerial EE STORE you try your radio set, make sure that there is no chance of any part of your aerial being grounded by touching or swinging against any grounded object. When no signals are received, the trouble may be due to the fact that the wire leading from the aerial to the set is touching the wire going from the set to the ground. To eliminate this trouble, use insulated wires for leads to and from the set. Interior of the farm bureau radio broadcasting station at Centerville, Ia. Farmers Own Broadcasting Station | | Soretepr yes the mails and the telephone too slow in distributing daily market information, progressive farmers of Appa- noose Cour.ty, Ia., have established the first radio broadcasting station to be op- erated by a farm bureau organization in the United States. The station, located at Centerville, and known as XYZ, is equipped with broadcasting and receiving sets of the latest type. More than 100 farmers’ receiving sets in the county listen each noon to market figures, news, descriptions of new farm methods and entertainment. C. W. Clarke, county agent, reports the innova- tion an unqualified success. Loop Aerial Folds into Neat Package ‘Ts increasing popularity of portable radio sets for camp. and touring use has brought forth many types of portable aerials. The most satis- factory of these is the loop aerial type that can be folded into a compact pack- age. Although this aerial is as effi- cient as any of the standard loops, it can be folded into a package slightly more than a foot long and having a total weight of only 2% pounds. The supporting frame of the loop aerial collapses, the wires are looped together and all inserted in a cylinder. Truck Carries Radio Band in Parade POPULAR SCIENCE MONTHLY CIENCE has created a rival for the marching band. In a recent Cin- cinnati parade a large fire engine chassis bore this giant radio receiving set, which supplied band and orchestra music for the marchers.

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iving sets arket farm W. LOVa- ide or the t Cin- engine eiving hestra POPULAR SCIENCE MONTHLY Tuning Coils—the Nerve Centers 59 of Radio Reception Various Forms of Inductance and Their Advantages By Jack Binns Radio Editor of POPULAR SCIENCEMONTHLY HE most important rule for the radio fan to learn in building his own set is that in the re- ception of broadcast wave lengths inductance is more important than capacity. Since inductance is obtained from coils of wire, and capac- ity from condensers, it fol- lows that he will have to use as much of his coil and as little of his condenser as pos- sible. For that reason I am devot- ing this month’s article to a consideration of various forms of inductances and their uses in radio circuits. Many Coil Types ‘The different types of coil in use are almost too numer- ous to mention in detail. Among them undoubtedly are still many of the old- fashioned single and double slide tuners. These invari- ably consist of a coil of enameled wire wound upon a tube of very large diameter. As a rule a brass rod is fast- ened above this coil, and a brass slider so arranged that it will run along the rod from one end of the coil to the other, making contact with the coil wire along a strip where the insulation has been scraped away. With such a coil simple vacuum tube circuits can be made without the use of a condenser, because in the in- ACCOMPANYING RADIO Using her piano wires as an aerial, Miss Frances Mayer, of New York City, easily brings in broadcasted radio music which she accompanies on her piano. Careful tuning of her radio set and skill as a pianist are required for this unusual feat efficiently wound coil itself is considerable distributed capacity. The simplicity of The wiring diagram in this form of coil makes it an ideal one for Fig. 1 (below) shows one the beginner. Its disadvantages include of the most elementary its excessive amount of distributed capac- forms of a conductively ity and the general inefficiency of the winding and contacting. The simplest form of circuit with such a tuner can be made by joining the aerial to the active end of the coil, and a ground wire to the slider. The vacuum tube will be joined to an A and B battery in the usual manner. A wire should be carried from the aerial side of the tuner to the grid condenser, and another wire from the positive side of the A battery to coupled double-circuit vacuum tube receiver, using a two-slide coil as a tuning element . the ground terminal. Tuning then is accomplished by run- ning the slider up and down the coil until the required number of turns are obtained. A variation of this form of tuner is a similar coil with two sliders attached, as shown in Fig. 1. The addition of the second slider converts the coil into am auto transformer, making possible the con- struction of a double circuit. The connections in this case will be the same as above, with one exception. Instead of carrying the lead from the positive side of the A battery to the ground, it will go to the second slider. Such a coil allows slightly greater selec- tivity than the single slide tuner. Slide or Switch In these tuners the brass slide takes the place of the switch in the variocoupler, The object is to bring into action a definite number of turns of wire. Probably the most efficient instrument ever devised for varying inductance is the variometer. The advantage of the vari- ometer lies in the fact that it affords a means of continu- ously varying inductance without any of the losses that affect other coils, such as ‘‘dead-end”’ losses, or capac- ity effects in leads to switch points. The cuits. ‘ae als Above is shown the same type of circuit as in Fig. 1, with a variometer _ substi- tuted for the two- slide tuning coil. The variometer supplies a continuously vari- able inductance ad- justable within small limits, thereby in- creasing the _ effi- ciency of the set simplest possible connections can be made to it, and these can be extremely short, a very valuable factor in vacuum tube cir- It will give excellent results, for ex- ample, if it is connected between an aerial and ground, as shown in Fig. 2, with a vacuum tube connected with it in the manner I have described for the single slide tuning coil. For fine tuning of inductance, the variom- eter cannot be sur- passed. Its disadvan- tages are the difficulty of winding it and the limitations of induc- tance changing range. In constructing the in- strument, shellac never should be used to bind the coils in place, nor should the wire be wound on heavy form- ers. A fairly efficient variometer can be made with two honeycomb or duolateral coils con- ERIN PS POPULAR SCIENCE MONTHLY 61

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60 POPULAR SCIENCE MONTHLY Figure 3 shows the most elementary type of in- ductively coupled double-circuit hook-up in which a vario coupler is used as the tuning element. Variable condensers can be added in both the primary and secondary circuits to increase the efficiency Fig. 3 generative set using the variocoupler, or in one using honeycomb coils, it may be y necessary to reverse the connections with the tickler coil in order to get good re- sults. A variation of the vario- Se a ‘f An elementary type of single-circuit regenerative receiver is shown in Fig. 4. The stator coil of the variocoupler is used as the coil common to both the primary and secondary circuits, while the rotor coil connected into the plate circuit is used as the tickler coil to provide regeneration nected in series on a two-coil mount. coupler is a coil arrange- ment, somewhat resembling it, but with two rotor coils inside the outer tube, as shown in’ Fig. 5. Such an instrument permits the use of a double circuit receiver with regeneration. One of the rotors can be used as the secondary coil; the other as the tickler coil for regeneration. In this case it is best to connect a vari- able condenser across the that the rotor coil acts as the feed-back agency. In this case the tube can be set into a state of oscillation by increasing the degree of coupling between the two coils, provided the rotor has sufficient induc- tance in its turns. The outside (or stator) coil of the vario- coupler is connected with the aerial and ground in the manner described for the circuit shown in Fig. 3. The grid circuit secondary coil. The condenser should be of as small a capacity as is practical. Now we come to a method of obtaining regeneration that has found great favor with radio fans, and one that is very efficient on short wave reception—the so- called “tuned plate circuit.”” This circuit takes advantage of the internal capacity of the tube. It has two main forms. One consists of Varying the coupling between two such coils will give a variometer effect. As soon as the radio fan has mastered the single circuit, he will desire to proceed to a more selective receiver, which prob- ably will be by means of a variocoupler. In simple double circuits, such as that shown in Fig. 3, where no condenser is used in the aerial circuit, it is imperative that two sets of switches be used, one for single turns, the other for groups of 10 turns. With the variocoupler, much of the tuning is done by varying the coupling between the rotor and stator coils. It will be observed that in every case the inductance of the rotor coil is fixed so far as the number of turns of wire is concerned. In the case of the simple double circuit a variable condenser should be joined across the rotor coil in order to get the full amount of effi- ciency. In tuning, the smallest pos- sible amount of the capacity of the con- denser, consistent with good results, should be used. Another Double Circuit Receiver Another method of obtaining a double circuit receiver is by- means of honeycomb or duolateral coils. In this case a two-coil mount is necessary, and two condensers are imperative. The condenser in the aerial circuit will Here the actions and qualities of the circuits shown in Figs. 3 and 4 above are combined. The stator and lower rotor coil produce the circuit shown in Fig. 3, while the regenerative action described in Fig. 4 is produced by the upper rotor a variocoupler with a condenser joined across its secondary, and a variometer in the plate circuit. The other has a variocoupler with a variometer in series with its secondary and another variometer in the plate circuit. Three Tuned Circuits In either form there are really three tuned circuits, each of which is placed in a condition of resonance with the in- coming wave. The feed-back of energy between the plate and grid circuits is obtained from the capacity coupling existing between the grid and plate in- side the tube. N NEXT month’s article Jack Binns will tell of im- portant new developments in the super-heterodyne receiver, popularly known as _ the ‘‘Rolls-Royce of radio.’’ ~ be connected in series with the coil, while the condenser in the secondary cir- cuit will be shunted across the coil. The results to be obtained from regen- eration are so advantageous that no fan will be content long to operate a straight non-regenerative receiver. In the case of regeneration, inductance is of extreme im- portance. There are two effective methods by which regeneration can be obtained; first by electromagnetic coupling, and second by electrostatic coupling. Elec- tromagnetic coupling is the most efficient and the most practical. It consists of feed-back action obtained through some form of coupled coils. Electrostatic coupling is obtained from capacity feed- back. To a certain extent, it can be ob- tained by the simple process of joining a variable condenser across the grid and plate terminals of the vacuum tube. The simplest form of efficient regenera- tive circuit yet developed employs a . variocoupler, as in Fig. 4, in such manner is connected with aerial and ground at both the switches, as in Fig. 4. The plate cir- cuit runs from the plate of the tube through the rotor _coil and the phones to the positive side of the B bat- tery. To many fans using hon- eycomb coils the idea of a regenerative receiver with only two such coils has not occurred. Yet such an ar- rangement is quite feasible. The advantage lies in the ease with which inductances are inserted in the circuit to meet any wave-length con- dition. Honeycomb coils have another great advan- tage, in the efficiency of their winding and design. In the single-circuit re- Original form of the Armstrong tuned plate circuit type of regenerative receiver. The circuit is the same as that shown in Fig. 3, with the addition of a variometer in the plate circuit. This produces regeneration by tuning the plate circuit into resonance with the grid circuit POPULAR SCIENCE MONTHLY , £ -_ yr) , ££ Tr T_T

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POPULAR SCIENCE MONTHLY 61 ng the : 1e using e e may be a %, O a e a 1 In ‘se the \ » tickler . y rood re- fy e vario- irrange- embling or coils ube, as Such an the use receiver One of used as |; the coil for his case | a vari- ‘oss the ~ Colored feathers are tied to a ould be fishhook to imitate a living al fly. Much skill is required to " ti a select and shape the feathers aining at favor is very —the so- s circuit capacity insists of or joined riometer er has a — = LIFELIKE FLIES, with | steel fish hooks for back- bones, are created with astonishing skill by Mr. and fs Mrs. J. H. Hornfeldt, of Ps Ridgewood, N. J. They are lly three 4 shown above in their work- is placed ‘ shop, fashioning feathers h the in- to supply expert anglers of energy with the indispensable lures ircuits is coupling CROWS AND BLACKBIRDS plate in- ARE DOOMED at the Experi- mental Farm of the U. S. De- partment of Agriculture, Arling- ton, Va. There the oldtime i scarecrow has been supplanted article by “Dad” Garrett, who in spite of im- of his 80 summers, is a crack onts in shot. “Dad” is shown at the left >ceiver preparing to bring down one of a cele vs the winged pests with his gun AN ARTIST IN GLASS is Her- man Miller, who makes lifelike glass models of strange undersea animals for the American Museum of Natural History in New York. He is shown above inserting mi- nute glass feelers in rotifers. By these feelers or suckers, the strange, leechlike creatures attach themselves to marine plants } bs | | ir . a a PAINTING TINY INSECTS, Miss Eleanor T. Armstrong car- ries on a strange profession in the National Museum at Wash- ington, D.C. Her subjects “sit” for her under the microscope POPULAR SCIENCE MONTHLY 63 pe ae I»?*1 ree nt WRr7yte# Ff fy

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62 Better Methods for the Housewife POPULAR SCIENCE MONTHLY This convenient lifter for taking eggs and vegetables from boiling water is in the form of pincers with hoop- shaped jaws that slip over the surface of the object to be grasped Stationary brackets for food choppers that catch in aprons can be replaced by this fold- ing bracket that will fit any kitchen table. By unscrewing a thumbnut, the device eo tk —e \~—~ =k @D cot a OL oO can be folded away an cm Glee Oh” oo od COU eee ooteo oweoelC mlC lC CU UCU Among the latest electrical appliances for the boudoir is a small motor-driven machine to which can be attached vari- ous implements either for manicuring or hair drying. For hair drying the device is mounted on an adjustable stand and a fan is attached to the shaft This appliance removes or tightens screw tops on jars or bottles. Tightening the wire cable around the top by press- ing the lever removes the cap. Turning the device in the op- posite direction tightens it The lid of this kettle locks into bracketed holders on the rim. The lid is held in place tightly while the kettle is tipped to drain water from its contents When opened, this combination ironing board and clothes chest offers two boards, one large and one small; a tilted rack to hold damp- ened clothes, and two shelves to re- ceive the clothes after they are ironed Pressing a button starts an electric motor that spurts water over the dishes from a revolving metal cone This unique four-story cooker util- izes heat usually wasted. Each of the four pots heats the next above An unbreakable metal top for perco- lators is said to improve the coffee 64 POPULAR SCIENCE MONTHLY the oil in small atomized particles with the 8. There should be automatic controls from the particular burner you are con- air before combustion. The result is that to start and stop the flame. sidering. A coal fire needs less chimney eee te ee ee. Doan, eee lame, A O?] and air feeds chould he easilv ad- area.

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‘s for that in be fold- able. _— vice away imney Coal or POPULAR SCIENCE MONTHLY Oil Fuel Which: A Few Pointers about the Heating Problem in Your Home By Collins P. Bliss Professor of Mechanical Engineering, New York University a room just as clean as will a $50 vacuum cleaner, yet housewives are using brooms less and less. The reason is obvious. A vacuum cleaner stirs up less dust; it does the work in vastly less time; it is operated easily and it leaves no pile of sweepings to be gathered up. The comparison between domestic coal furnaces and modern oil burners is very similar. Where oil fuel is used, no clouds of dust come up from the cellar to injure health; a sup- ply of heat is ob- tained easily and maintained evenly with little trouble, and the disagreeable job of cleaning out the ashes is elimi- nated. Oil as Fuel The question often asked is, “Can I use oil satisfactorily as a fuel in my home?” You certainly can if the proper equipment A FIFTY-CENT broom will sweep Ox the market today are many oil burners that will work equally well in a five-room home or a 25-room dwelling. On the other hand, there are burners that will not work at all success- Burners that have aaunet been found to work satisfactorily appear at first to be very complex. Such varts as fans, motors, and thermostats give one the idea that they are difficult to operate. This impression is erroneous. The aver- age woman thinks nothing of driving a car with mechanism more complex than that of the oil burner. The clutch, brake, gearshift, and other parts of the automo- bile are as nothing to her. Why should she not be able to handle an automatic oil burner just as easily? Attempts to simplify oil burners have not, to my mind, proved successful. I be- lieve that future development will be along the line of improving the present successful burners equipped with positive fuel feeds and with automatic controls. The next few years will see a development in oil burners as remarkable as has been se development of automobiles since 1905. “What advantage has an oil burner over coal?” is another question. MAKING THE CELLAR LIVABLE is installed carefully. ‘THESE two pictures show how one home owner, by installing an oil burner, transformed his furnace room from a dingy place of dust and ashes into an attractive, carpeted billiard and play room. At the right: The cellar as it was, lit- tered with ashcans and ashes, and marred by an ugly coalbin. Above: fully. The same cellar with its installation One advantage is convenience. For ex-’ ample, a thermostat, located in the living room, registers the temperature in the house. When the temperature drops be- low a predetermined mark, an electiic control is operated, the burner lights auto- matically and the furnace generates heat. Similarly, when the temperature is too high, the burner automatically shuts off. This automatic process continues day and night whether any one is in the house or not. Oil Burner Saves Many Steps Obviously there is no need of going into the cellar to shovel coal into the fur- nace every little while, nor is there night banking of fires and a cold house in the morning. Then, too, there are no ashes. All the oil burns without soot or smell. The gases go up the chimney and no residue remains. Houses that today require the services of a man to remove ashes can save the cost of his labor by installing an oil burner. A good oil burner, properly installed, can be operated just as cheaply as a coal furnace. From 140 to 150 gallons of oil in actual use are re- quired to give heat equivalent to that produced by a ton of coal. At 91% cents a gallon this is equiva- lent to about $14 a ton. With coal at about $16 a ton at present, it is apparent that oil is cheaper. Installation Cost Of course, the original investment with interest must be considered. A coal- burning furnace in a seven-room house can be transformed to an automatic oil-burning furnace forfrom about _ $600 to $800. Yet the saving in fuel over a period of years will go a long way toward paying the principal and interest of this investment. Then, too, it is not unrea- sonable to assume that coal prices will continue to mount as in the past and that they may climb soon toward $20 a ton. At such a figure it is ab- solutely certain that oil would be the more _economical fuel. To install an oil burner all that is nec- essary is to remove the grates of the coal furnace, insert the nose of the burner and fasten it in place. A careful survey should be made to see that there are enough radiators or regis- ters to give heating surface sufficient to heat the house. At the same time the most advantageous location for the ther- mostat should be determined. This is im- portant because a direct draft of cold air or direct heat from any source will cause the thermostat to register falsely. Another question often asked is, “What type of oil burner shall I buy?” As I said before, numerous types of oil burners are available; they fall under three general classifications: vaporizing, air atomizing, and steam atomizing burners. In the vaporizing type, oil is fed by drops to a burning vat or bowl, lighted with a match. A jet of air produced by the chimney draft impinges on the sur- face of the oil, supplying the oxygen for combustion. No attempt is made to mix POPULAR SCIENCE MONTHLY | | er een gene ee t ens a Ser 65 if peesom + «~~ , tie L, > phen Tt... fk Ss

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64 the oil in small atomized particles with the air before combustion. The result is that much carbon often forms, causing large chimney losses and a poor transfer of heat. While these burners will work well in places where the natural draft is good, they cannot without pre- vious test be applied suc-

POPULAR SCIENCE MONTHLY 8. There should be automatic controls to start and stop the flame. 4. Oil and air feeds should be easily ad- justable. 5. The burner must fit the furnace. A big burner in a small furnace will only

from the particular burner you are con. sidering. A coal fire needs less chimney area. 7. The flames from the burner must not strike an unprotected surface and so burn out the boiler flues, tubes, or other parts, The oil burning system

cessfully to every type of house furnace. utilizes the principle that air and minute particles of oil form a highly combusti- ble mixture. The air is pro- vided either by means of electric fans or an air com- pressor. The air is shot from a nozzle at great speed, sucking oil from another nozzle close by. The oil is broken up into small par- ticles and the mixture is ig- nited, either by a gas pilot light or by an electric spark

Observe These Points Thesteam atomizing type but uses superheated steam as the carrying agent. “‘Which type and which particular burner should be selected?” is the final ques- tion to be answered. Since there are a number of differ- ent burners that will work well, it is well to observe the following points: 1.. There should be a posi- tive air supply, provided by compressed air, fan, or

[ EXTENSION FILL = The air-atomizing type pf IN ALLEY B REGULAR FILL BS

: ne =< ae plug Typicai installation of an oil-burner system, showing location of oil How to Insure against Danger N THE use of oil as a heating fuel in your home, a few simple precautions are offered by experts, as follows: inci 1. . Be sure the apparatus is installed in accordance with ye lg tenet epee regulations of fire underwriters and city ordinances. 2. Inspect the system daily. If a pilot light is used, see that the tip is free from carbon. Never use a naked light in hunting forleaks. 3. Before starting the burner, be sure all flues are clean and dampers are open wide. 4. Keep the furnace room free of papers, rags, and other rubbish. 5. Don’t allow unignited oil to spray or drip from the burner into the furnace. 6. Don’t allow any person to experiment with the apparatus. 7. Have the entire system thoroughly overhauled at the be- ginning of each heating season, preferably by the company that installed the burner. includes two tanks, the burner, piping, and electric wiring. A large storage tank varying in capacity from about 200 to 1130 gal- lons, is buried outside the house. City ordinances re- quire adequate protection of this tank. Some localities require a one half to one foot coating of concrete. In other places a covering of sand and a slab of concrete are deemed sufficient. Be- fore purchasing a burner it is well to investigate the local ordinances regarding the installation of furnaces, For Oil Storage Oil from the buried tank is led to a smaller tank of about 60 gallons in the cel- lar. Here again some city ordinances require that the oil be pumped into the cellar instead of using gravity. Many ships long ago dis- carded their coal bunkers and substituted oil tanks. Then factories, large office buildings, and apartment houses fell in line. Thou- sands of such installations are now in operation. In

steam. 2. There should be a dependable source of power control for auxiliaries, such as gas or electricity. waste fuel and in time injure the furnace. 6. The chimney of your house should be large enough to take away the gases all these plants, the boiler rooms look as spick and span as hospital operating rooms. It is only a question of time when oil will replace coal in many homes also.

Storm Sash Opens when Window Is Raised [LIFTING a window, if it is equipped with the clever device shown here, simultaneously lifts the storm sash, thus eliminating the extra effort usually re- quired to raise and fasten the storm sash indepen- dently. The secret of the device lies in two lifting arms fastened to the inner sash and ex- tending to the storm sash. The outer ends of the arms are fitted with roller bearings that run on tracks attached to the side members of the storm sash. Thus, as_ the inner window is raised, the storm window swings out.

Six-Story Building Moved by Six Horses. S* Los Angeles horses recently accom- plished the astonishing feat of moving a six-story brick building, weighing 11,000 tons, for a distance of 125 feet. They did it with the aid of a series of tracks over which the structure moved on rollers. The building housed a hotel which had to be moved from a site purchased by Los Angeles for municipal buildings. Nineteen double tracks, a total length of a mile, were used. Forty-five lines of cable, totaling 8100 feet, and three cap- stans conveyed the power supplied by the horses. The cable, tracks, and capstans were so arranged that the six horses pulled with a strength equal to that of 5400 horses, a multiplication of 900. The moving was, of course, 900 times slower than it would have been with 5400 horses pulling. Fourteen hundred jacks were used. The distance covered in any day was 40 feet.

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are cOn- chimney nust not so burn er parts. system ks, the electric storage capacity 130 gal- side the ances re- ‘otection localities one foot te. In ering of concrete nt. Be- ourner it vate the egarding furnaces, age ‘ied tank - tank of 1 the cel- ome city that the the cellar avity. y ago dis- bunkers iil tanks. rge office partment . Thou- tallations tion. In she boiler pick and iS. when oil 3; also. eS. three cap- lied by the i capstans rses pulled it of 5400 900. The nes slower 400 horses used. The as 40 feet. How to Fix Your Plumbing First Aid Methods Any Householaer Can Use when Water Pipes Leak or Burst in Winter POPULAR SCIENCE MONTHLY By John H. Schalek, M. E. O MOST of us the plumb- ing systems in our homes are like our teeth—we do not realize that we have them until something goes wrong. Then, when something does go wrong, we are quite helpless. Even the handy man who does a little carpenter work and painting about his home and perhaps tinkers with his auto- mobile rarely will: attempt to repair his plumbing, simply because he thinks that plumbing work is difficult and mysterious, requiring a very special kind of skill and unusual and complicated tools. This is not so. Nearly any man, with the com- mon tools found in almost every household, and without special mechani- cal skill, can do his own plumbing repair jobs. Most of these are emer- gency jobs—such as mend- ing leaks that develop suddenly, endanger- ing valuable furniture, rugs, wallpaper, and other household possessions. Every man should know how to give first aid in such cases as these. It is no more sensible to permit a serious leak to ruin your house furnishings while you try to sum- mon a plumber than it is to let blood flow from a cut in your hand while you wait for your doctor. Turning Off the Water The first thing the amateur plumber should learn is how to turn off the water supply to the house. In many modern homes a shut-off valve, similar in appear- ance to the shut-off valve of a steam radiator, will be found beside the water meter. If there is no shut-off valve in the house, the water supply may be turned off at the curb box. This box usually will be found near the street curb at the front of the house. If the position of this box is not known, often it may be located with the aid of an ordinary compass. First find the place in the cellar where the water pipe enters; then, following the line of this pipe and holding the compass as close to the ground as possible, walk slowly to the curb. As you approach the iron curb box, the needle or disk of the Locating the curb box with a compass.- The compass needle is deflected as you approach the iron box CU’LL be surprised as you read this article to discover that you don’t need to be even a halfway mechanic— you hardly need to know one tool from another—in order to doctor the inevitable plumbing ills about your home. simple. terms an expert mechanic tells just how to do it quickly and effectively. This is one of the most helpful of the articles appearing in POPULAR each month, telling the amateur how to do odd jobs around ‘the house. You'll discover much real recreation and enjoyment in iearning how to ‘‘fix it yourself.” SCIENCE MONTHLY In The first step in an emergency —turning off the water in the curb box. One full quarter off the water with a key. The water supply can be shut off from certain pipes by turning the valves found ‘beneath sinks and. wash- bowls, or in the cellar. If you do not know what pipes in your plumbing system these valves control, try the valves one after the other, and tag them against possible emergencies in the future. Faucets and other valves that leak be- Severed Pipes Easily Joined ‘water. sent 88, After cutting the broken water pipe, insert each of the severed ends in an or- compass will be de- [occu flected and it is then a simple matter to un- cover the box and shut Hammer each severed end over the union; join the half unions turn shuts off the average cock cause the washer has become worn, waste an almost unbelievably large quantity of Leaking at the rate of only 10 drops a minute, the ordinary faucet will waste about 200 gallons of water in a year. Two leaking hot-water faucets will cost the householder at least a dollar a year in gas alone—enough to pay for £0 good washers. To replace a faucet washer, first shut off the water from the house. Then close the faucet tight. Next unscrew the large nut connecting the handle with the body of the faucet. When this nut is free, un- screw the faucet by the handle. If the Screw Is Corroded When the core of the leaky faucet is out, look at the small screw that holds the washer in place. If the screw appears to be badly corroded so that it might break off when the screwdriver is applied, cut the washer out with a sharp knife and take the screw out afterward, using pliers if necessary. Trim the new washer around the edges until it fits closely into the recess in the core. Then replace the screw, screw in the core of the faucet as far as it will go, and tighten the large nut. Leaks at pipe joints—joints where the pipe screws into couplings, unions, and other fittings—are due to strains cr ex- cessively worn threads. Unscrew the joint and smear a little thick paint, tar, or other heavy oil com- pound on the external thread—that is, the thread inserted in the joint. If this should not stop the leak, coat the thread with a low melt- dinary half union. Then chip off the tongue of the union as shown above How three sections of pipe are joined tightly by ordinary pipe unions ing point paste solder and heat with a flame until the solder has a re a PII REET EE : / | 4 | ¢ | : i, ; | POPULAR SCIENCE MONTHLY ¢

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66 melted; but do not permit the solder to fill up the threads. It is well to have some lith- arge about the house. This is a yellowish powder that may be ob- tained at any hardware store. Mixed with boiled linseed oil, it forms a thick paste that can be used on pipe threads to make them tight. Leaks in pip- ing due to rust This simple emer- gency leak clamp is made of a_ small stick, a wire, a stone wedge and a piece of rubber. Hammering the wedge toward the wire fulcrum brings pressure on the rub- ber covering the leak and freezing are repaired more easily than is generally im- agined. When the emergency arises, two or more machinist’s clamps, obtainable at hardware and often at five and ten cent stores, a piece of ordinary rubber gas tubing split longitudinally and a piece of heavy sheet iron will stop even very se- rious ruptureseffectively. Iftheclampsare not available, anordinary strap hinge and a large carriage bolt will prove effective. An emergency leak clamp, successfully used by gas companies on gas lines holding more than 200 pounds pressure to the square inch, also has been used satisfac- torily to stop water-pipe leaks. Making the Emergency Clamp All you need is a piece of wire, a piece of soft rubber, such as gas tubing, auto shoe, or inner tube, apiece of iron to act as a lever, and a piece of iron or wood, prefer- ably in the shape of awedge. The farther the wedge is driven in, the greater will be- come the pressure on the rubber packing. A piece of rubber large enough to cover the burst section of the pipe and wrapped tightly on the pipe with heavy twine or wire also is a satisfactory way of repairing leaks temporarily. Contrary to popular belief, it is im- practical, if not impossible, to repair a leaking lead pipe by soldering. The pipe must be severed and rejoined. Since exceedingly skilful manipulation is required to cut the pipe at the point of leakage and wipe the joint, the fol- lowing method will prove the simplest for the average man: Cut the lead pipe with a saw. Select an ordinary pipe union large enough to allow the lead pipe to slip through readily. The tongue of the half union A split washer, screwed in through the leak hole, holds the head of the stove bolt inside the boiler so that it can’t slip through POPULAR SCIENCE MONTHLY Two ways to stop a pipe leak temporarily. Above: A piece of rubber large enough to cover the burst section of the pipe is wrapped tightly with heavy twine or wire. At right: Ordinary gas tub- ing and a piece of heavy sheet iron are fastened about the broken pipe with machinists’ clamps is chipped, sawed, or ground off. One severed end of the lead pipe then is in- serted in the union and the end hammered over the union seat. The same oper- ation then is performed on the other end of the pipe and half union. After both pipe ends have been fastened in the union halves, the ends are brought together and coupled by the union ring. In cases where the rupture is large, so much of the lead pipe must be cut out that it will be found impossible to bring the ends together. In this case two unions are needed. A piece of lead or iron pipe of suitable length is inserted between the unions, bridging the gap between the pipe ends. Unions of this size may be bought for about 50 cents each and a job for -Two Simple Ways to Mend Small Holes in a Boiler WOMB S WAG Smail holes in the boiler can be stopped either by insertihg a tapered wooden plug or by fitting a stove bolt, as shown above which a plumber would charge $10 actu- ally can be done for less than one dollar and a half. When a hot-water storage tank de- velops a leak, most householders consider it beyond repair. But a small hole can be stopped easily by driving a tapered plug of white pine or walnut into the hole. The writer knows of one case where a plug in- serted three years ago is still doing service. The plug should have a very gradual taper with the entering end almost as sharp as a needle. It is driven in with a hammer after it has first been soaked in water and the projecting end cut off within half an inch from the tank surface. Where the hole in the tank is one quarter inch in diameter or larger, a most «effective and workmanlike repair job can be made by using a stove bolt, two inches or more in length, a nut, a rubber washer, and two iron washers. Split one of the iron washers with a cold chisel. Slip the head of the bolt through the hole. Now place the split washer over the bolt and slide the washer ’ against the boiler. Holding the _bolt end firmly in one hand, screw the washer in through the hole with the other. Once the washer is inside the tank, the head of the bolt cannot be pulled out. All - that is necessary then is to put the rubber and iron washers on the protruding bolt and screw the nut tight. Cover All Exposed Pipes Leaks resulting from the bursting of frozen pipes cause much plumbing trouble at this time of year. Water pipes should not run in exposed walls. If you have such pipes in your home and they are ac- cessible, they should be wrapped with sheet wool of a thickness of not less than three inches. But the surest way of pre- venting pipes from freezing is by shutting off the water at night and at other times when the house is without heat. After the water is shut off, the pipes should be drained at faucets, drains and flushes. If the house is left vacant in the winter, about two quarts of kero- sene should be poured into closet bowls and a pint into each sink, washbowl and bathtub to prevent the traps from freezing and bursting during the severe weather. These are plumbing jobs that every man should be able to do. Performing such simple repair tasks yourself will save you money—not only in plumb- er’s bills but in house furnishings that easily might be ruined even by a very small leak. Parts of the stove bolt plug shown at the left—a-~split iron washer, rubber washer, unsplit iron washer, bolt and nut 1 & POPULAR SCIENCE MONTHLY aed i, @ @

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actue dollar ik de- nsider can be d plug 2. The lug in- ervice. radual ost as with a ked in ut off urface., is one a most ob can inches washer, Split with a 1 of the Now ver the washer ling the » hand, shrough side the ie bolt it. All n is to on the t tight. 2S sting of trouble 3 should su have rare ac- ed with ess than r of pre- shutting er times After ; should flushes. _ in the of kero- » closet ‘h sink, prevent bursting at every rforming rself will 1 plumb- ings that yy a very

Autos in China Must Wear Mud ‘‘Splashers’’ RDINARY mud fenders are not suffi- cient in China, for the law there requires that pedes- trians, as well as a car and its occupants, be protected from the splashing of mud. Accord- ingly, all auto- mobiles in China are equipped with “splashers’” on all four wheels. Each splasher consists of a strap- iron frame hung from the axle and en- circling the wheei, from which hangs a heavy fringe of fiber or leather long enough to touch the ground.

POPULAR SCIENCE MONTHLY

A MODEL of a helicopter from plans drawn in 1843 by Sir George Cayley was constructed recently by Paul Garber, custodian of airplane models in the Na- Remodels Helicopter Invented 80 Years Ago

tional Museum at Washington, D. C. The design, although conceived years before an airplane flew, is strikingly similar to those of recent helicopters.

Broadcasting in the Jungle ‘Ts is a broadcasting station in the South American jungle—an amaz- ingly noisy signal drum hollowed out of a log and used by the Tucanos for main- taining communication when hunting.

Playing with Thunderbolt HE scientific experiment of passing more than a million volts of electricity through one’s body ordi- narily would ter- minate one’s scien- tific career. But Earl Holm, asenior at the University of California, Ber- keley, Calif., here is shown perform- ing that experiment with impunity, manufacturing thunderbolts as nonchalantly as might ancient Vulcan. The secret of his apparent daring lies in septuple in- sulators on which the ‘operating’ chair rests. Hi

Strange Spider Monkey and Its Baby Captured

ee ice a celine = é - Ee. re pater 7a. Gah . \ ‘ * Eee — annsretjaion cae Ps . as pn pment aided NER i. Ss rae \ os ni = : ward Sean ne norman te

, eee rae

HIS spider monkey with her baby, which is said to be the only one in. captivity, recently were pre- sented to the San Diego, Calif., zoo by a detachment of United States marines stationed at Nicaragua. Thespider monkey is so called on ac- count of its ex- tremely long, slen- der limbs and long tail. These are constantly em- ployed in climb- ing.

| This Pig Walks on 26 Toes

N A Nebraska farm recently a pig with 26 toes was born, one of a litter of seven, the others being normal. Both front feet are double, and the left hind leg terminates in a veritable cluster of toes.

a OF aa | * POPULAR SCIENCE MONTHLY 69

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68 Reservoir 6 Rinse with many times the terrible destructive force of those that proved so deadly in the closing months of the Great War are being developed in experiments at Camp Meade. The illus- tration shows a lately evolved model splintering trees on the testing ground. Not all of the experimental work is with fighting tanks. Tanks that can transport large guns, ammunition, in- fantry, signal apparatus, construction ma- terial, safely and rapidly for miles over A forest of columns, 35 feet high, supports the enormous roof POPULAR SCIENCE MONTHLY Roofed like a Cathedral HIS covered reservoir of reinforced con- crete, an unusual piece of construc- tion on account of the magnitude of its dimensions, was completed recently for the waterworks of Cleveland, Ohio. Its enormous roof, approxi- mately 1000 feet long and 500 feet wide, consists of groined-arch pan- els, supported by a forest of thick col- umns. Standing within the Bald- win Reservoir, one could readily im- agine himself in a great cathedral. The volume of concrete used in making the units —walls, 1196 col- nanns, 2208 groined-arch pan- els, and as many sections of floor slab—amountedto 104,100 cubic yds. Uncle Sam Builds Huge Army Tanks ground deeply pitted with shell holes and blocked by obstructions are vital to the success of the terrible fighting tank. “BALSAM wool,” a new heat insulator and sound-deadening material for build- ings, excelled only by human hair and sheep’s wool in insulating efficiency, is prepared from pulp, wood bark, and sulphite screenings. It is flexible and resistant to fire and water. It weighs only 253 pounds to 1000 square feet. eee Toothpaste Tubes Filled by Machinery He’ machinery puts toothpaste, cold cream, and shaving cream into the tubes is pictured above. The empty tubes, in sockets, run on an endless band under a nozzle, where they are filled with the cream preparation drawn from a vat. After the filling, they are carried to a sealer that clamps to- gether the open ends, bends them over, and stamps them into a tight seal. The tubes are held in place by the semi- circular metal strip shown at the left until they are directly above a chute, which conveys them to a packing box. Automatic Car Coupler Saves Injury to Crew How the two coup- ler units work HOOK INTO SLOT APRON LIFTS HOOK SPRING ~~ N AUTOMATIC safety coupler for mine cars has been perfected to lessen the number of casualties caused by the crushing of hands and bodies of workmen in making up trains of cars and later in uncoupling them. The coupler is made in two sections, one fitting on the rear of the car and the other on the front. When two cars thus fitted are rammed together, an apron on one section of the coupler raises a hook on the other. This hook immediately drops into a slot in the first apron. Sufficient play is allowed in the hook connection to prevent breaking of the — coupler due to impact when the train is started with a jerk. WHEN soft coal is burned in the furnace, soot can be removed quickly and easily from flues and heating surfaces by throw- ing a pound of common salt, thoroughly dried, on the burning fuel bed. Immedi- ately upon charging with salt the furnace becomes filled with dense, white fumes. ‘POPULAR SCIENCE MONTHLY

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Filled paste, cold n into the run on an vhere they reparation illing, they clamps to- hem over, seal. The the semi- t the left » a chute, ng box. upler 1rew > two coup- its work - oupler for rfected to caused by bodies of of cars and o sections, ar and the ) cars thus 1 apron on a hook on tely drops the hook ng of the © ne train is e furnace, and easily by throw- horoughly Immedi- | he furnace > fumes. This Milk Bottle Uncorks at the Bottom MILK bottle that uncorks at the bottom, making it possible to draw off the milk while retaining the cream in the bottle, has been invented by Ray Dunn, of Tipton, Ia. The bottle has a_— small opening at one edge of its bot- tom surface. This opening normallyis closed by a cork to which is at- tached a cord or tassel. When the cork is pulled out, the “milk will flow from the bot- tom of the bottle, thus making it easy to empty and solving the problem of separating the milk from the cream. The hole also assists in cleaning the bottle, which is filled in the usual way. To MAKE sure that a ring or other piece of jewelry is gold, drop it in nitric acid. Neither gold nor any precious stone will be harmed. The acid quickly attacks imi- tations, whether they be of precious stones or of gold. Windmill Supplies Light ‘fying when viewed | Y INSTALLING a windmill on his roof, a resident of East Cleveland, Ohio, lights his home almost without cost. The windmill consists of eight per- pendicular “sails” attached at top and bottom to circular, revolving frames. These are connected with a special one- kilowatt generator. The windmill is about 15 feet high and 50 feet above the ground. * POPULAR SCIENCE MONTHLY 69 Above: A diamond- bearing river bed ex- posed by diverting the stream from its course. At the right: Crush- ing blue clay from the mines to expose the gems for gathering How Kimberley D WO methods by which the diamond, king of geras, is thieved from Nature’s treasure chests are revealed by the illustrations above, showing scenes in the famous Kimberley district in British South Africa. The larger picture shows a diamond- bearing river bed exposed by diverting thestream. Such streams carry diamonds down their course much as many Western streams in the United States bear down nuggets. Claims are staked out in the dried bed, 50 per cent of the value of the discoveries going to the Government iamonda: Are Nee 4 . sj and 50 per cent to the claim holder. As in placer mining, virtually no digging is necessary, many of the stones lying on the surface. The smaller picture shows a tractor crushing clods in a blanket of blue clay that has been brought up from the diamond mines and spread over the ground. This clay lies weathering for a year, during. which it is plowed and smashed frequently. The conditioned clay then is taken to a separating mill. Barbed wire charged with a deacly electric voltage guards the field. Manufacturing Lightning in Movies ‘THs machine produces flashes of lightning for moving pictures. The flashes are quite harmless, but are realistic enough to be terri- r slaaiel on the screen. The apparatus, which is of wood, is wired like a street arc lamp, except that several carbons are used instead of only two. About a half dozen of these are fastened to an up- right arm and a single large carbon to a _ projecting arm. The latter can be moved back and forth by the attached rope. When the single carbon is brought oe Fd jee . flash of light is produced, registering with spectacular effect on the moving picture film. ee in’ contact with the group, a great. © Keystone The arclight machine that produces dazzling lightning flashes 1 | | | J DYODITIT AD CM'IBAIS’YC’ RAPA tt

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a hc AR BO ON ps ee ares yi te ran cee ne es : ae lig ptadiik a Sener ‘POPULAR SCIENCE MONTHLY A UNIQUE type of fire hose nozzle, which, in addition to throwing a stream on a fire also supplies a curtain barrage of water to protect firemen from the heat, has been developed by a San Francisco concern. A recent demonstration proved that the umbrella-shaped screen of water nullified the effect of the heat sufficiently How the special nozzle, at left, throws an umbrella- shaped water screen Nozzle Throws Water Barrage for Firemen to permit firemen to insert the nozzle into a tank of burning gasoline. Also, the pro- tecting stream, by cutting off the supply of oxygen from the fire, caused it to be ex- tinguished almost instantly, a thing it would have been difficult to accomplish with the ordinary solid stream. Using this nozzle, one man can handle a line carrying 150 pounds pressure. Springs to Heat Iceland pte rae eg is planning to utilize its natural hot springs and geysers in place of coal to heat the whole country, according to reports from Bergen, Nor- way. Preliminary plans call for wooden pipe lines to carry the hot water from the springs to the cities. Rocker Quickly Converted into Wheel Chair ONVERSION of a rocker into a wheel chair is accomplished in a few min- utes by clamping to its base the special set of four wheels as shown below. The small rear wheels turn in any direction for steering. The foot rest is adjustable and the front wheels can be locked in posi- tion. A nurse evolved the invention. A wheel chair made from a rocker Novel Megaphone Amplifies Voices of Singers E; W. CORNELL, of Adrian, Mich., has designed this strange megaphone for use by singers. The large flare of the funnel is said to furnish amplification of tone without distortion. The peculiar face piece was devised to produce clear enunciation by permitting normal use of the face and mouth muscles. The appliance is said to be particularly good for church singers and broadcasting. Says We Can Signal Mars HAT it is entirely possible for the earth to signal Mars by means of signal lights produced at high altitudes by airplanes is the belief expressed by Dr. A. M. Low, an English inventor. By chemicals, he says, there are ways to produce signals of sufficient size to be readable on Mars, if intelligent beings live there. Wireless, he says, is impracticable. Because wireless waves travel in curves, he observes, it is hard to hit the target. One-Man Ice Saw Driven by Auto Engine N INGENIOUS ice saw driven by an automobile engine cuts nine inches deep at the rate of three feet a second. It is the invention of S. E, Kurtz, of Sac City, Iowa. The saw is connected directly with the crankshaft of the auto engine, eliminating the transmission. Because of its lightness, automatic spring saw hoist, and automatic gage fingers, one man can cyerate it. Hope for O. D. Uniforms , te American Chemical Society is attempting to perfect a domestic dye that will make the faded O. D. uniforms of General Pershing’s men look alike in color. [Safety Candle Holders for the Christmas Tree ERSONS whose homes are not wired for electricity may use _ lighted candles for Christmas-tree decoration with comparative safety, thanks to a device invented by a Pittsburgh man. This con- sists of a series of extensible metal arms. Fastened to the trunk of the tree, they hold the candles beyond the branches and decorations. The arms may be adjusted to any angle, and they are fitted with pans to catch the drip from the candles. The ap- paratus may be used also for electric lights. Arms hold candles away from tree POPULAR SCIENCE MONTHLY

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‘iven iven by ts nine e feet a f S. E. with the ninating ightness, itomatic e it. aw Drms ciety is astic dye forms of in color. s for 2@ ot wired lighted ‘ion with a device ‘his con- al arms. ee, they ches and to any pans to The ap- ic lights. "© Key. stone Gas Stove Placed in Tub Heats Bath Water OB fasscessnpapta an odd design of .gas stove, a German inventor has de- vised a quick method of heating water for the bath. After the bathtub has been filled with cold water, the gas stove is placed in the tub until the water is hot enough. The design of the stove permits a maxi- mum of heat to be transmitted to the water without danger of explosion or ex- tinguishing the flame, for the flame jets are in the upper part of the stove and the lower part is watertight. Handle of Wa!king Stick Serves as Flashlight HE difficulties and hazards of walking over rough roads by night are greatly lessened by this ingenious combination of : walking stick and flashlight. A battery and lamp are set in the handle of the stick, the lamp being at- tached in such a way that it appears to be only a metal cap for the handle. The pushbutton activating the lamp is located inconspicuously under the han- dle. Finding small change, reading house numbers, or looking at one’s watch are illustrations of the invention’s usefulness. Aspirin Freshens Flowers 8 ee best way to revive withering flowers is to dose them with aspirin, according to the announcement of a French scientist. He claims to have dis- covered that an ordinary aspirin tablet dissolved in warm water will freshen the most delicate cut flowers in vases. POPULAR SCIENCE MONTHLY Bathers —— by Novel | Lifeline 71 HREE drown- ing persons were rescued re- cently from what is said to have been one of the roughest surfs ever recorded on the Pacific coast by a remarkable _tor- pedo-shaped life- saving buoy that enabled the res- cuers to carry a life-line to the per- sons in distress. The device has a range of 1000 feet from shore and weighs but 25 pounds. Two persons, only one of whom need be a swimmer, operate the apparatus. A reel containing 1000 feet of sounding wire is suspended from the shoulders of the man on shore. It is attached also to a wide belt about his body so that the strain of pulling in the reel is distributed. Connected with the reel by a sounding wire is a cylinder, with torpedo-like ends to cut the water. The wire connects also Concrete Granary Filled by Motor A CONCRETE granary and corncrib, scientifically ventilated and contain- ing a motor-driven elevator that fills it automatically, has been designed and con- structed by F. W. Benjamin, on his farm at Bloomington, IIl. While the building follows the design of the familiar silo, it is constructed of con- The rescuer swims with the hae attached to reeled line ‘The concrete granary end its storing machin- ery, showing motor-driven elevators that convey corn from the wagon with a barnes worn by the second man, who swims out with the buoy to the vic- tim. The cylinder has great buoyancy and, it is said, can be carried nearly twice as fast as the standard carry life- buoy. If the wire becomes entangled in sea- weed or wreckage, the rescuer releases a snap swivel that frees him from the wire and swims in, using only the cylinder. crete staves. On two sides of the building the staves are supplied with vent holes that permit the air to circulate through the stored fodder and prevent it from spoiling. Under the structure is a passageway large enough to admit a horse and wagon or motor truck when the fodder is being stored. ‘The corn or grain is dropped from the rear of the wagon into a trough, whence elevators convey it up- ward and store it automatically»when a motor is started. The fodder is re- moved from the crib by gravity. The designer of the granary points out that it is fireproof, ratproof, and does not have to be painted. Buildings of this sort are adapted not only for the farm, but may be used also for the storage of coal and similar materials. POPULAR SCIENCE MONTHLY 73

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f t . q a a

72 POPULAR SCIENCE MONTHLY World’s Biggest Torch-Cutting Job

heat of an acet- ylene torch, the 27- inch solid steel shaft shown here was cut in two in about 15 minutes recently in a railroad yard in Los Angeles, Calif. This is said to be the biggest job of acetylene cutting ever undertaken. Sixteen tubes of oxyhydrogen gas were consumed, maintaining a constant tempera- ture of 3500° F. Protractor and Depth Gage Combined in One RECENT contribution to the list of time-saving machine tools by a con- cern in Athol, Mass., is a combination protractor and depth gage in which the protractor arm serves as the blade of the depth gage. Any desired angles can be laid off or measured and the depth of machined channels can be determined. ‘When thedevice is used as a pro-

tractor, any angle in one half a circle can be laid off with the blade, and the angle of a piece of work measured. For use as a depth gage the blade can be set at any length within six inches. When thus used, a set-

Above: Measuring the depth of a slot in a machined casting with the adjustable protractor-depth gage

screw is loosened and the blade set to project any dis- tance below the protractor base. Lining up the blade along the 90° mark at the top insures accurate measure- ment.

I ;< M in i } | At the left: How the protractor arm Serves as the ‘blade of the depth gage. For adjustment, the set- screw is loosened and the blade set to any desired depth DEPTH IEASURE et SS mS ee ee

Combination Machine Tool Cuts Two Ways

Roughing and finishing with two-way tool 74

Tae novel machine tool and holder, designed for cutting on both the for- ward and return strokes is the recently patented invention of a Chicago shop foreman. The device is equipped with two cut- ters, one a roughing tool, and the other a finishing tool. On the forward stroke the finishing tool rides over the work while the roughing tool makes a cut. On the return stroke the operation is reversed. Finally, when the tool-holder has been fed: all the way, the surface of a casting or other work is finished.

DEVELOPMENT of a new system of mak- ing iron castings from “long-life molds” has been announced by a carbureter manu- facturing company of Detroit, Mich. The new mold, it is reported, will produce six two-pound castings a minute. NDER the fierce’

Setting hand saw with rotary tool Hand Saws Set in Minute by New Rotary Tool A ROTARY saw set recently patented is said to set a hand saw accurately in one minute. Guide bars hold the saw in place and an adjustment at the bot- tom, by a turn to the left or right, ac- commodates the particular width of the saw being set. Different set wheels are required for saws with varying numbers of points to the inch. These are changed easily. Drawing the set once the length of the saw completes the setting.

Barrel-Header Is Driven by Oil Pressure N ENTIRELY self-contained barrel- heading press, driven by oil pressure has been devised by a Florida man. A pump supplying the pressure is mounted directly on the base of the machine and connected by ‘a short nipple with the base casting. In this casting are oil passages and a rotary valve controlling the operation of the plunger. The oil reservoir is cast into the base of the machine. Two operating pedals raise and lower the press.

POPULAR SCIENCE MONTHLY

ce ea tee es Ee OOP BOC

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; G recently com tests tool nute yl tented urately he saw 1e bot- ht, ac- of the ‘ed for ints to easily. of the n by barrel- ressure 1. ure is of the nipple ing are rolling The oil of the ise and recently completed in the laboratories of the United States Forest Service at Mad- ison, Wis., have ex- ploded the theory held by builders that knots in timber necessarily impair seriously its sup- porting strength. By means of a huge ma- chine that applies a vertical pressure of 1,000,000 pounds and is capable of receiving timbers 30 feet long and 12 inches square, it was demonstrated that knots have virtually no influence on the stiff- ness of timbers, and so, little effect on the column strength. This discovery, the laboratory officials say, is of immense importance, since many thousands of dollars now are wasted an- nually in building operations by discard- ing knotted timbers or using timbers larger than is needed to support a load. The results of the recent tests, however, do not mean that knotted timbers are to be deliberately sought, since knotted timbers come from the upper portions of trees, and have less density and elasticity than wood from the lower trunk. In the tests Southern yellow pine was demon- strated to have a column capacity as high as 432,600 pounds. million - pound New Adjustable Drill for Metal or Wood A NEW adjustable tool for cutting cir- cular holes in sheet metal, wood, or fiber has been perfected by a tool-manu- facturing con; cern in Cincin- nati, Ohio. A lead hole is first drilled by a cen- tral drill, to which the tool- holding frame is attached. On this frame slide two cutting blades, which can be adjusted to cut holes from one to four inches in diameter and up to seven-eighths inch deep. The frame of the tool is of malleable iron, while the two cutting blades are of tool steel, ground and tempered. Adjust- ment is accomplished by means of two knurled thumbscrews. A scale on the metal body aids in obtaining accurate diameter dimensions. The tool is especially useful for work on automobile dashboards. Ts editor will be glad to supply, wherever possible, the names and addresses of manufacturers of devices mentioned in this issue of POPULAR SCIENCE MONTHLY. A short column of yellow pine under tremendous pressure in the POPULAR SCIENCE MONTHLY 73 Million-Pound Pressure Proves Strength of Knotty Wood test machine The massive construction of the timber-test- ing machine, capable of ex- erting a million pounds pressure, is shown at the right. The ma- chine weighs 150,000 pounds Huge Steam Shovel Is Hill Climber TEAM shovels of such size that man- ufacturers never before attempted to mount them on anything but standard railroad trucks recently have been suc- cessfully equipped with traction wheels, giving them extreme mobility and the ability to ascend and descend steep slopes easily. The shovels are’ hauled by the forward wheels, driven, by powerful shovel engines, and steered by rear wheels. Above: A steam shovel mounted on traction wheels climbing the steep side of an 80-foot pit in a stone quarry at Elmhurst, Ill. At the right: The same shovel at work in the quarry In a quarry near Chicago a shovel 85 feet long, with traction-wheel equipment recently descended into and climbed out of a pit 80 feet deep. Such a feat would have been all but impossible for the same machine on tracks.. At a Pennsylvania quarry a huge traction wheel shovel was moved in one day a distance that under the old track-laying methods would have occupied at least 10 days. A _ shovel mounted on traction wheels also was suc- cessful in replacing a derailed dump train on the tracks in a few hours in a Michigan quarry. Engineers say traction wheels for the mounting of large shovels possess many advantages over railroad trucks, including greater mobility, easier accessibility to the face of an ex- cavation, elimina- tion of tracks and consequent lowering eect AION Cc ge etme wat POPULAR SCIENCE MONTHLY 75

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, Fa 74 POPULAR SCIENCE MONTHLY Relief Springs Smooth Rough Roads ” » \epamargrncel springs of a_ distinctly new type that are claimed to give Pullman-car ease on the meanest road, may be attached to most makes of auto- mobile at small cost. The rear auxiliary relief spring is com- posed of double transverse, straight BODY SUPPORTED ON ROLLERS teeta 809 ing, 4 ‘ Se, : Teh 8 The rear auxiliary relief, showing double transverse springs with roller bearing joint, and roller bearing body support Views Scenery in Auto gebrratagge an who may wish a closer view of attractive bits of landscape, or who have a leaning toward amateur astronomical investigation, will be inter- ested in the homemade automobile tele- scope that a Vermont man has attached to the windshield of his car. The instru- ment is mounted on a ball-and-socket bracket, permitting it to be set in any po- sition to observe earth or sky. An eye piece with a half-inch focal length enables observations to be taken without getting into uncon.fortable positions and alsomag- nifies the images in the telescope 40 times. The telescope has a 3 %-inch mirror with a focal length of 20 inches. Pe ee ec N laminated springs. These are secured to- gether at their centers, with a roller-bear- ing oscillating joint between. Each end of the upper spring is connected with the side frame by a roller-bearing device, and each end of the lower spring is held in contact with the main side springs by a rubber - padded stirrup with a ball bearing between the springs. This gives a frictionless connection and al- lows a great range of spring or axle movement. It pro- vides also a three- point suspension for the rear of the frame. It is said that this arrangement reduces the effect of end thrust move- ment andsidesway and will damp out sharp rebounds. ‘Telescope Daredevil Says Front Seat Is Safer A NOVEL theory as to the relative safety of the front and rear seats of an automobile is offered by J. H. Van Normann, a circus daredevil of Bridgeport, Conn. He asserts that the rear of the car is more dangerous to ride in than the front, and claims he proves it by the way in which he performs the thrilling stunt shown here. According to Van Normann, centrifugal force willhurl out the occupants of the rear seats in an accident, just as he is hurled 50 feet into a net by this agency when his bicycle finishes its descent of a long in- cline and shoots off into space. The photo- graph shows how the front of the bicycle falls and the rear rises as he performs the spectacular feat. Van Nor- mann’s stunt leap, demon- strating how rear of bicy- cle rises , anc DOPTITAR CLIEFNG'K MONTH VY Arrow indicates position of the recording dial Checking on Trucks O KEEP track of the movements of motor trucks or delivery wagons, a Cleveland manufacturer has devised the ingenious dial recorder shown here. It may be attached to the dashboard, be- neath the seat or to any other convenient part of the body. A dial of paper surfaced with wax, on which are marked the 24 hours of the day, divided into 10-minute intervals, is con- tained within the case and attached to clockwork that causes it to make a com- plete revolution once in 24 hours. The case also contains a pendulum that swings from side to side with the sway of the car. To this pendulum is attached a sapphire-pointed stylus that scratches the waxed paper as it moves. Moving along the edge of the dial, this stylus records when the car was moving or at rest. ae) Auto Engine Cooks Meal while You Ride N OVEN attachment for automobiles has been perfected by James E. Z. Fowle, of Preuss, Ore. The oven has a compact rectangular casing, shaped so that it will seat snugly over the exhaust manifold of the engine. The top carries two rods terminating in hooks that engage over the radiator stay rod, thus holding the oven securely. Coffee, stews, and boiled eggs may be prepared while the car is in motion. Hot cakes or fried eggs can be cooked on a hot plate at the bottom of the oven.

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vements of wagons, a levised the 1 here. It board, be- convenient th wax, on of the day, als, is con- ttached to ake a com- Ts. Julum that he sway of attached a scratches e dial, this as moving Meals e itomobiles mes E, Z. ven has a shaped so e exhaust inating in iator stay securely. 3 may be tion. Hot d on a hot POPULAR SCIENCE MONTHLY 75 How to Enjoy Your Car in Winter By George A. Luers, M.E. _ Noted Auto and Mechanical Engineer my home one morning early last December I saw a neighbor stand- ing at the curb. He was gazing with A I was walking down the steps of pained expression at his automobile, a “smart car of a well known make, aaa only a few months before. As he heard me approach he looked up and pointed silently toward the front of the car. Water was pouring from the bottom of the radiator in a flood. Radiator Was Only Half Drained “Frozen, eh?” I observed, for the night before had brought the first really cold weather of the year. “No,” he denied. “It can’t be frozen. I haven’t used the car in a week, and I drained the radiator the last time I put the car away. I noticed it was leaking when I started to back out just now. I can’t understand it.” I stepped to the front of the machine to examine it. The core—the honey- comb-like center—of the radiator was split where it joined the lower tank and along the fissure was a strip of ice. I puzzled for a full minute before I found a possible explanation; and, when I questioned the car owner, my guess proved to be correct. Instead of actually draining his radi- ator in the only way in which it can be done thoroughly—by removing the plug at the bottom of the lower tank—my neighbor had attempted to draw off the water by turning the cock beneath the water pump. This had permitted the water to flow from the upper part of the radiator, but because the cock is on a level with the lower tank, this tank had been left full. The water had frozen when the temperature fell the night before. As a result a new radiator core was necessary before the car could be used again and this meant a heavy repair bill. Freezing Water Is Common Trouble My neighbor’s experience is a typical instance of the sort of trouble into which ignorance, inexperience, and carelessness often bring motorists during cold weather. Operating an automobile during the winter is a different thing entirely from driving the same car in milder seasons. The automobile has been improved in a thousand ways since the days when every owner put his car up for the winter, but not yet can it accomplish the transition from relatively warm weather to cold unless it is prepared for the change. Everybody knows that water freezes, yet the most frequent cause of trouble and expense to the winter driver remains the freezing of the water in the cooling systems of cars. The man who lets this happen deserves little sympathy. You know when cold weather may be ex- pected, and you should prepare your car for it in advance. Before the first cold weather comes drain your radiator at night. Better an automobile in winter is a different thing entirely from driving the same car in summer. An automobile is like a human being—to weather the transition from warm sunshine to the snow and ice and freezing temperatures of winter it must be prepared for the change still, fill it with an alcohol or other non- freezing solution. It is better to pay for a few pints of alcohol which you really do not need than to be forced to pay a bill Preparing, Your Car HERE are important. pointers to observe in preparing the body of your car and its accessories to weather the snow and ice and bitter cold of winter: ~* TOP Repair breaks and untacked seams. CURTAINS Replace broken or discolored glass. WIND- Fasten bolts,- oil SHIELD hinges and provide a wiper. DOORS Adjust lost-motion devices, oil latches and hinges. BODY Tighten frame bolts and dash bolts. FENDERS’ Tighten nuts on brackets and braces. | PAINT Enamel bare spots | and use wax polish. GENERATOR é CARBURETER # - 4 CLOSE COLD-AIR RISABES ADJUST THE NEEDLE VALVE ADJUST THE TO SUPPLY GENERATOR ADDITIONAL TO CHARGE AT FUEL A HIGHER RATE How to make car How to save starting easier your battery for a split radiator, broken pump, or cracked water jacket. There are many anti-freezing com- pounds that you may use, but denatured alcohol is as efficient as any and is probably the most easily obtained. A proportion of one-fifth alcohol to four- fifths water will prevent freezing at temperatures above 15 degrees, while 2 mixture of half alcohol and half water will not freeze above 34 degrees below zero. Since anti-freeze solution is some- what expensive, it is well to prevent loss by leakage by inspecting the hose con- nections, gasket and pump packing and renewing any of these which may require it. As a further precaution a leather radiator cover is valuable for retaining heat when the engine is idle. Some Ordinary Winter Precautions Cold weather also affects lubricating. Oils will congeal in the winter, making the engine and transmission stiff. This requires much additional power from your battery in starting, and tends, of course, to discharge it. Light grades of engine and gear oil should be used in winter unless, of course, the manufacturer of your car expressly advises against this. The lighter oils will remain more fluid than heavy oils in cold weather and con- sequently will reach bearings and gears more readily. Tire trouble, too, is frequent in winter. Chips of ice cut the casings; water from melting snow seeps into the cuts, freezes and rapidly destroys the rubber and carcass. You will do well, then, to start the winter with a set of new tires, to make frequent inspections and to repair cuts as they develop. A set of good tire A TODO Ha I ee 8 Re POPULAR SCIENCE MONTHLY

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76 chains for use on icy, snow-covered or sloppy highways is, of course, an es- sential. In addition to caring for such details as these, a thorough inspection of the car to detect and correct possible me- chanical defects should precede its winter use. In the winter you need all the power your motor can develop. Be sure POPULAR SCIENCE MONTHLY their heat rapidly in cold air. This loss of heat must be compensated for by adjusting your carbureter for hotter mixture. The needle valve or nozzle should be opened wider to supply the extra fuel needed. Leakage in the air inlet of the car- bureter and failure of the ‘‘choke’”’ to close the air inlet properly will give you On the market are many appliances designed to aid you in starting your car in cold weather — primers, electrical heaters for the carbureter, and similar apparatus. One of my acquaintances even carries a thermos bottle filled with hot water, which he pours over the car- bureter when he is ready to start his car. Most of these devices really do make starting easier, but, if you have there is no loss of power through made your car right mechanically leaky compression or worn valves. If the motor turns over easily on compression strokes, it is a sign of leaky compression which should be corrected by a new set of piston rings. Then inspect the valves and guides. If they are worn, they should be replaced. When the Lubricant Congeals Congealed lubricant in your transmission case will make the action of your transmission slug- gish. To compensate for this, adjust the sliding gears for free movement and increase the ten- sion of the clutch springs. When the highways are covered with snow or ice, your brakes are under an exceptionally heavy strain. For safety in winter driving, be certain that your brake linings are not worn. If they are, have the brakes relined before you risk driving your car. The brakes should be adjusted loosely for winter driving, so that grit, thrown against them from KNOW YOUR CAR NON-VIBRATING COIL Your Spark Plugs—The sparks that jump across the gap between the points, or terminals, of the spark plug are produced by a high-tension induced current in the manner shown in this diagram of a typical ignition system. Low-voltage current from the battery is led through the ignition switch to an induction coil, which “‘steps up” the electric voltage from six to more than 5000. The battery current passes from battery to coil, then to interrupter, through ground and back to the battery. The high-tension current, induced by the coil, passes through the timer, across spark gap, through ground and back to the coil. before the winter season, you prob- ably will not need them. Flooding the carbureter is an easy way of starting some makes of cars, but is wasteful of gasoline and tends to form carbon. You can make starting easier for yourself by preparing for it when you stop your motor. Pull your choker rod out and open your throttle the instant you shut off the ignition. This places a heavy charge of fuel in the engine. Since the first movement of the motor adds to this charge when you press your starter pedal, the chances are that the car will start on the first turn. Special Care Is Needed Driving and traffic conditions vary so much in different sections of the country that it would be useless for me to attempt to suggest rules of conduct to be observed on the roads during the winter. Especial care is necessary, especially when snow wet roads, will not wear the linings out too fast. Sharp turns are dangerous in winter, because of slippery traction. For this reason your steering gear should be adjusted so that the lost motion in the steering wheel will be slight—not more than an inch. The steering gear should not be made so tight, however, that the wheels cannot ‘be swung instantly to counteract the least tendency to skid. Driving in and out of frozen wheel tracks and over- banks of snow subject the wheel bearings to heavy strain. Examine the bearings before using your ear for the winter and replace bearings that are worn too badly to be adjusted. The engine and cooling system lose RELINE BRAKES AND ADJUST LOOSELY BATTERY FULLY CHARGED ( trouble in starting your car when the en- gine is cold. Replace any worn or leaking parts in the air inlet and adjust the choke to close fully. The difficulty of starting even me- chanically perfect cars in winter tends to wear out the battery quickly. The generator can be adjusted to charge the battery at a higher rate. The average motorist probably will do well to have this adjustment made at a good service station. It is probably safe to say that a generator adjustment that will charge the battery at the rate of 20 amperes when driving at 30 miles an hour will be about right for the average car. RENEW PISTON RINGS AND VALVES : WHEEL BEARINGS ADJUSTED TIRES FREE OF CUTS, AND CHAINS PROVIDED or Aiacamnent ADJUST CLUTCH SPRINGS AND- TRANSMISSION GEARS prams Pe eas « DRIVE SHAFT AND TORQUE ROD CONNECTIONS SHOULD BE TIGHT or ice is on the highways, reducing friction between the tires and the road. Your car cannot climb the steep grades that it ascended easily when the roads were dry; there is a tendency to skid when descending hills or making turns. Watchfulness is necessary both on the roads and in the garage during the winter; but if you will exercise intelligent care, you can drive your car with just as much safety and enjoyment as in summer. RE you planning to buy a new car this year? In mak- ing your selection don’t fail to look over the new improvements in 1924 designs which will be described in next month’s issue. STEERING GEAR SHOULD BE DEPENDABLE. BuT NOT TIGHT RENEW HOSE, GASKETS, PACKINGS, AND’PROVIDE RADIATOR COVER CARBURETER SHOULD NOT LEAK AIR AT CONNECTIONS This diagram shows the necessary adjustments of various parts of the automobile mechanism to meet the requirements of safe and comfortable driving during the winter months DODTIT AD COUIPAIS’'ER AACYVAST LST V

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POPULAR SCIENCE MONTHLY 7 “~ 1 'T'heNewest Aids to Better Motoring lectrical . similar ces even with hot the car- tart his do make ou have 1anically ‘ou prob- Flooding r way of ‘ars, but 1d tends g easier g for it or. Pull nd open ant you is places | in the ovement Danger of accident in s charge entering or stepping from starter a car in the dark is that the avoided by this three- turn. lens step lamp _ that illuminates the openings d d of both doors, the run- cca ningboard and ground Valuable automobile robes or coats can be safeguarded from theft by this clamp lock. An adjustable plunger, locked by a key, causes the contact points to grip the robe like a vise ynditions sections vould be ampt to t to be ; during care is en snow reducing }and the he steep vhen the y to skid turns. h on the e winter; nt care, as much ner. buy a Heavy loads can be n mak- carried behind the car fail to on this combination fe t bumper and luggage omen s rack designed for such vill be uses as carrying milk | ; issue. to market. The rack eee é ; af This tire chain is said to be unusu- is built of angle iron These safety light signals are ally effective in preventing skidding, controlled by a _ two-way and to be very easy on the tires switch on the dashboard. Upper picture shows rear signal; lower, front signal These two photographs show the operation of an ingenious expanding luggage carrier that folds to the size of a suitcase when not in use. The carrier is supported by the spare tire that swings down to a horizontal position on hinges at the rear GEAR LE-BUT IT This extension on the gas lever of a We vuildddlddddlddiudscMlllllllllddbd Ford car holds a pushbutton that In this friction shock absorber, steel makes it possible to dim the lights of A tubelike footrest serves as a con- blades attached to the axle move the car without removing your hand venient container for the tire chains. between leaves of specially treated from the wheel. The extension also The container also may be used friction material attached to frame facilitates control of the gas lever as a gasoline or water container dd hc iitllallllUt ides Cdllllddde d POPULAR SCIENCE MONTHLY 79

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Labor-Savin tion illustrated in Fig. 1, an auto steering wheel of the usual fixed type can be converted into a hinged or tilting wheel. This applies, however, only to a car on which the spark and gas quadrants are not mounted on the wheel. It is particularly useful in converting an old car into a sport model. The wheel spindle is cut off and slotted to form a hinge joint and an extension fastened on, asshown. This extension is threaded for a large wingnut. A key prevents the wheel from slipping. B' THE relatively simple modifica- WO nails and a block of wood are used to make the simple tester for spark plugs shown at Fig. 2. A hole is bored near the end of the block, as indicated, and the nails are driven in at an angle so thatthe points will be about Y in. apart. In use, one nail is touched against the terminal nut on the spark plug, while the other is placed against the metal base of the plug. —F. M. P. SPARK PLUG Fig. 2. Spark tester Y PUR- CHAS- ING a 50- gal. drum of gaso- line, the car owner can save from 2 to 5 cents a gal- lon. The main objec- tion to buying gasoline this way is the dif- ficulty of handling the drum. This can be overcome by provid- ing two brackets, as shown in Fig. 3, to support the drum at a level corresponding to that of the delivery truck. Tworollers are set in each bracket in such a way that the drum can be rotated without diffi- culty. A large filling bung is drilled, tapped, and fitted with the usual metal spigot, and, once made, this special cap is kept for each new barrel of fuel. To pour the gasoline, the drum is turned over until the spigot is in a convenient position, and afterward is rolled back with the spigot at the top, so that there will be no leakage. Lubricating oil drums can be handled in the same way.—A. C. T. ANN TN TS homemade creeper illustrated in Fig. 4 is unusually comfortable be- cause the upper two fifths of its bed is hinged so that it can be raised when neces- Fig. 7. Cheaply made radiator filler POPULAR SCIENCE MONTHLY sary to support the workman’s head and shoulders. The materials used in con- struction are short lengths of narrow pine flooring, a pair of 4-in. strap hinges, four ball-bearing casters, and a 5/16-in. nail rod about 40 in. long.—R. A. FRANKLIN. END OF WHEEL SPINDLE i : (0) _—> i WINGNUT STEERING WHEEL J TILTED POSITION fm ee Fig. 4. An adjustable rest for the head and shoulders makes this garage creeper un- usually comfortable for work under car Fig. 9. S spreader ring SPREADER IN US REMODELING an old style auto it is sometimes a puzzle to know where to carry the storage battery. One way is to fasten one of the many commercial bat- tery boxes to the runningboard. Another is to place the battery under the back seat, if space allows. Perhaps the best idea is to arrange suitable brackets under the floorboards. To fit the angle-iron supports properly to the car frame, the work should be done, if possible, at a time when the body of the car has been removed. Once the iron 5 Kinks for the Autoist cross pieces are in place, as shown in Fig. 5, they cannot work loose. Note that they are bolted or riveted to the top flange of the frame. This is so that the drive-shaft tube will clear them better, but if there seems no danger of the tube’s striking the irons, perhaps they can be bolted to the lower frame flange, which makes it unnecessary to remove the body. N IMPROVEMENT upon the ham- mer or punch method of cutting bolt holes in gaskets is to use a tool made by welding a \4-in. ball bearing to a length of 4 or \%-in. rod (Fig. 6). When the gasket has been put in place, the ball is laid on each hole in succession and struck sharply. One blow cuts a clean hole. —B.S. R. HE radia- tor filler in Fiz. 7 isa real labor saver for the home garage. It is simply a 3- or 4-gal. bucket with a hole drilled or punched near the bottom. In the | ole is soldered a short piece of iron pipe. This is con- nected by means of a lengthof light, flexiblerubber hose about 1 ft. long with an elbow that serves as the filling nozzle. The joints are made with some hose clamps or wire. A hook sol- dered to the elbow fastens over the rim of the bucket and holds the hose up when the pail is being filled or carried.—J. L. BRACKETS —1}}!! Fig. 3. Drum brackets CO motorist uses a simple glare de- flector made as shown in Fig. 8. The deflector is a green celluloid disk fastened with a small screw and washers on the in- side arm of the windshield wiper. Since the wiper is arranged to move across the windshield, and the glare disk can be swung around in a circle, it is possible to place the deflector quickly in any position desired.—J. N. T. - ANY garage where Ford cars are overhauled, the spring spreader shown in Fig. 9 will be found to save much time when removing or placing the spring shackle bolts. Two bars, one with a U-bend, are connected with a turn- buckle and the ends are pointed to fit back of the spring eyes.—L. B. C.

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ist 1 in Fig. te that the top chat the better, e tube’s can be » which 1e body. ne ham- ing bolt nade by ength of e gasket laid on sharply. low cuts n hole. a { radia- yr filler . Tis a labor for the garage. imply a | 4-gal. t with a rilled or ed near ottom. » Lole is ereda piece of pipe. is con- ed by } of a of light, erubber about 1 ag with ow that as the nozzle. ints are 2 with > hose ips or ook sol- to the fastens the rim ip when —J.L. lare de- 8. The fastened 1 the in- Since ross the can be ssible to position ‘ars are preader to save cing the ne with a turn- d to fit POPULAR SCIENCE MONTHLY 79 ome Workshop Arthur Wakeling, Editor Making To AKING toys for the kiddies’ = Christmas is the most en- elas’ | joyable work that comes ‘ into the home workshop. Every | man who is in the least handy with tools likes to build playthings. It | | | is fun to put them together; they | always seem to turn out success- fully; and they are immensely ap- preciated by the children. This is especially true when the toys are so interesting, sturdy, and easily constructed as_ those _ il- lustrated—a toy tea cart and game table, a miniature garage, and a bunny wheelbarrow. These were designed especially for POPULAR SCIENCE MONTHLY, and the work- ing details, prepared by George F. Kaercher, are given in full in Home Workshop Blueprint No. 29. Although essentially a girl’s toy, the tea cart can be used by the entire family as a portable game table. On the tray—either on the face or on the back, as preferred—is painted a checkerboard. The table can be used also for many other games, and its chief advantage is that it can be wheeled about from room to room or carried up and down stairs. The tea wagon can be made of white- wood, pine, cypress, or any other wood that is easily worked. It is 18 in. wide, RAFTER ROOF BOARDS 11X23 X24" BOARDS 18"X18"X" This large toy farage is built of wooden strips covered with wallboard 2 ft. long, and stands 2 ft. high. The table top is 34 by 18 by 24 in.; and the drop leaves are cut from pieces 34 by 7 by 24 in. The back posts are 14% by 14% by 21% in., and the front posts are the same stock, but only 17 in. long. The main top rests on a mitered frame Sturdy home- made toys that form fine Christ- mas gifts Although a girl’s toy, this tea cart can be used by the whole family for games made of two pieces 34 by 244 by 22% in., and two pieces % by 2% by 16% in. The lower shelf is % by 15% by 21% in., but itis just as well to use 11%-in. stock, if it is at hand. The heavy shelf rein- forces the construction, and it is essential in building toys always to make the parts as strong as possible. The top side rails are % by 3% by 201 in., and one end rail is % by 2% by 13 in. The drawer front is the same size as the end rail. The sides of the drawer are % by 2% by 14 in., the back 4 by 1% by 12% in., and the bottom 4 by 13% by 12% in. The two runners are % by 1 by 19% in., and the two guides, 4 by 4% by 14in. The two drawer rails are % by 2 by 138 in. The table leaf braces are cut from pieces 54 by 4% by 6) in. and are hinged to the side rails. The wheels are cut from pieces 1% by 10 by 10 in. They can be lightened by a cut-out design, as shown, or they can be left solid. Baby carriage or toy express wagon wheels, or any other kind of small wheels can be used, if at hand. The front axle is 1144 by 1% by 19 in. The small back wheels are cut from pieces 34 by 2% by 2% in., and turn on wooden pins 1% in. long and % in. in diameter. The two handle brackets are cut from one piece % by 6 by 9in. A %-in. dowel 15% in. long is used for the handle bar. The tray bottom is % by 16% by 21% in. with sides 4 by 1% in. mitered round. Two washers for the front wheels, one drawer knob, two drawer stops 4% by % by 1 in., two tray, handles 9/16 by % by 3% in., rubber or felt tray feet, screws, nails, and brads are also needed. Mortise and tenon and doweled con- struction is preferable because of its strength, but the parts can be nailed or screwed together with much less work. Small angle irons, mending plates and box corners can be used to advantage in strengthening toy furniture of this type, ys to Delight the Kiddies BOTTOM 974x124 x Ze t he Eg . A ‘ - = GUY IR Ox eS Gi a ea Uf pj a io NES ° 30 s | screw-2'2x Ke The bunny wheelbarrow makes a certain hit with the younger children when the joints are merely nailed or screwed together. The simplest method of finishing the tea wagon is to give it one or two coats of enamel undercoating, or flat white paint, and one or more coats of enamel. It is advisable to use only the best materials in (Turn to page 107) POPULAR SCIENCE MONTHLY 81

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pet ete ae emma ee HOME WORKSHOP DEPARTMENT: OF POPULAR SCIENCE MONTHLY for Christmas How to Make a Radio Set OTHING could be more in keeping with the Christmas spirit this year than the presentation to the household of a good, reliable radio set. The joy that such a gift will bring to every one in the family is certain to be lasting. The radio set offers a solution to the question, “How can we make evenings at home enjoyable enough to compete with the club and the movies?” For ease of construction, simplicity of operation, ‘and general all-around effi- ciency the double-rotor type of tuning unit has few rivals. Why it has not en- joyed greater popularity is hard to under- stand. A tuner of this type is the heart of the two-stage receiving set illustrated. A rear view of the unit is shown in the photograph of the back of the set; the front view is illus- avoid confu- trated in connection with 0m: the Pho- Front and rear views of the set. To 3 : aphs were Jack Binns’ article on = oo! before page 59. wivine n> Two rotors, one at piled. Note each end of the stator jical panel tube, are used. The and the double rotor secondary coil of the cir- tuning unit cuit is wound on one rotor while the tickler coil, used to provide re- generation, is wound on the other rotor. Taking into consider- ation the selective fea- tures of double circuit tuning, combined with the great signal strength obtained by regenera- tion, the receiver de- scribed this month is one of the most compact and efficient it is possible to construct. The circuit provides for three coils, a primary, a secondary, and a tickler coil, placed in inductive relation with each other. The primary coil consists of 63 turns tapped at every seven turns, with a 23-plate con- denser placed across the coil to provide closer tuning. The coil is made of No. 20 s.c.c. wire wound on a tube 4 in. in diam- eter and 414 in. long. A Condenser Tunes the Secondary The secondary and tickler coils are fixed inductances consisting of 50 turns of No. 24 s.c.c.. wire wound on 31%-in. rotors. A 23-plate condenser, placed across the secondary coil, is used to tune the secondary circuit. It is not necessary to adhere strictly to the dimensions given if the tubes, rotors, and wire mentioned are not obtainable. The stator can be of any convenient size from 3 to 4 in. in diameter and of a length ¥ in. greater than the diameter of the rotors that are to be used. The diameter of the rotors can be from \% to 1 in. less than the outside diameter of the stator tube. The wire used can vary from No. 20 to No. 26 single or double cotton covered and the number of turns used on the rotors can vary from 30 to 50. In the illustration, A and B are the aerial and ground posts respectively. C and R are 23-plate Vernier variable By Joseph Calcaterra Of POPULAR SCIENCE MONTHLY’S Radio Staff HRISTMAS is the high-water mark of the broadcasting sea- son. Operas, concerts, plays, vau- deville turns, dance music, lec- tures, sports—every imaginable form of entertainment is then ‘in the air.”’” You can enjoy it all if you assemble this exceptionally fine two-stage tickler coi! feedback receiver designed by Mr. Calca- terra as the ideal Christmas set. condensers. D and Q are rheostats, being of 30 ohms resistance for the new 3-volt, .06 ampere tubes or of 6 ohms resistance for any of the other standard tubes. E is a standard inductance switch pro- vided with nine switch contacts. Switch stops marked S are provided at each end of the contacts to prevent the switch arm from slipping off the outside contacts. F is a grid leak of 1 or 2 megohms, and G, a grid condenser of .00025 mfd. H, N, and T are tube sockets. The G terminal of the H socket, one of the F terminals of the N socket, and one of the F terminals of the T socket are hidden from view. I and O are standard audio frequency transformers. I may bea high ratio trans- former, but O should be a low ratio one. J and P are double-circuit jacks, while S is a single-circuit jack. K is the primary winding; L the tickler winding, and M the secondary winding. U1, U2, U3, U4 Us, Us, and U7 are binding posts used for battery connections. The general location of the instruments on the panel and baseboard is clearly shown on the photographs. The size of the panel is 18 by 7 by 3/16 in. The base- board is 17 by 6144 by % in. The thick- ness of the baseboard is not important. No difficulty in making the proper con- nections will be experienced if the direc- tions given below are followed carefully: A single wire is used to connect the be- ginning, No. 1, of the primary winding K with the No. 2 or stationary plate ter- minal of condenser C and the aerial post A. Another wire is used to connect the ground post B with the No. 1 or rotary plate terminal of condenser C. The No. 1 terminal of the condenser is then con- nected with arm E of the inductance switch by a flexible wire connection. Now connect each tap of the primary winding K, beginning at the first tap from the beginning or No. 1 end of the winding with its respective switch contact. The end of the winding, marked No. 2, is used as a tap and con- nected with the last switch point of the in- ductance switch. Connect the No. 1 terminal of grid con- denser G with the G terminal of socket H. Then connect one end of a wire with the No. 2 terminal of the grid condenser; lead the wire straight up toward the top of the set until it is at a height on a line with the No. 2 terminal of con- denser R; and bend it toward that terminal and fasten the end of the wire to the terminal. One of the leads of the secondary coil M is then con- nected with the wire men- tioned in the last paragraph at a point where the wire passes over the rotor shaft. If a combination grid con- denser and leak is not used, one terminal of the grid leak should be connected with one terminal of the grid condenser and the other terminal of the grid leak connected with the other terminal of the grid condenser. Next connect one of the leads of the tickler rotor winding L with the top spring of jack J and the other lead from the same winding to the P terminal of socket H. Wiring the Filament Terminals Run a wire connecting one F terminal of each socket with binding post Uz. The wire can be run along the back edge of the baseboard, but make sure that it cannot make contact with any of the other bind- ing posts. If bus-bar wire is used, it should be covered with spaghetti tubing. The other lead from rotor winding M can now be connected with the wire men- tioned in the last paragraph, the connect- ing wire being run diréctly back to the wire connecting the F terminals of the sockets-or to the F terminal of socket N, to which the wire mentioned in the pre- ceding paragraph is connected. A wire is then used to connect the No. 1 terminal of condenser R with the F ter- minal of socket T to which the wire con- nectige one of the F terminals of each socket with binding post U2 is connected. An insulated wire, bared only at the (Turn to page 126) i i le || 6 | i ee

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* as | How You Can -arefully: t the be- inding K late ter- rial post nect the or rotary ‘he No. 1 hen con- ductance tion. primary tap from winding t. The 2, is used nd con- the last of the in- tch. he No. 1 rrid con- sh the G ocket H. t one end 1 the No. the grid ead the ht up ‘set until line with of con- t toward isten the erminal. ; of the shen con- ire men- aragraph the. wire or shaft. rid con- ot used, grid leak with one ondenser rid leak al of the s of the the top ad from minal of inals terminal Te. The ge of the t cannot er bind- used, it | tubing. iding M ire men- connect- k to the s of the ocket N, the pre- he No.1 e F ter- vire con- of each nnected. at the Small odd pieces of modern furniture make welcome Christ- mas presents for the home. You yourself can easily make them for your family. There is no particular trick to constructing porch swings, tables, telephone sets, etc. Furniture, woodwork and floors of your home can be made to harmonize if a little taste is used in finishing them. You can easily refinish dingy, shabby, scratched wood. Our method involves practically no expense. All you need is a little time—a brush — and JOHNSON’S WOOD DYE. POPULAR SCIENCE MONTHLY 81 Give a Beautiful Finish To Wood-Craft Presents Johnson’s Wood Dye is very easy to apply—it goes on easily and quickly, without a lap or a streak. It pene- trates deeply, bringing out the beauty of the grain without raising it—dries in 4 hours and does not rub off or smudge. JOHNSON’S WOOD DYE Johnson’s Wood Dye is made in fourteen beautiful shades, all of which may be easily lightened or darkened—full di- rections on every label. In Wood Finishes you get just what you pay for. If you buy cheap brands you may be sure they are manufactured from cheap raw ma- terials, cheap labor and the com- pleted job will be a disappointment and the finish will not stand up. The Johnson Line of Artistic Wood Finishes is complete—it includes Johnson’s Wood Dye—Paste Wood Filler—Enamel and Undercoat— Permacote Wall Finish—Floor and Sani-Spar Varnish—Prepared Wax —and everything necessary for your ( furniture, floors and trim. If you are building or remodeling you should have our book on refinishing. The finish of your floors and interior trim is a matter of great importance, for a beautiful piece of -hard wood may be absolutely ruined with the improper finish, whereas an ordinary piece of wood is a pleasure to the eye if well finished. FREE-This Book on Home Beautifying This Book tells how to finish wood in artistic stained and enameled effects. Gives practical suggestions on mak- ing your home artistic, cheery and inviting. Tells just what materials to use and how to apply them. In- cludes color card—gives covering capacities, etc. Use coupon below. “The RAPER TREATMEN | PROPER TE FLOORS. (a : i wooDW ORK and S. C. JOHNSON & SON, Dept. PS 12 RACINE, WIS. (Canadian Factory—Brantford) Please send me free and postpaid your Instruc- tion -Book on Home Beautifying and Wood Finishing. 4 The best dealer in paints hereis........... Se ARE...) bee | f MY: NAME... .. +0000; sanemeeousboacnges i MY ADDRESS .......seseecererreereeeers i CITY & STATE. .... cei ec cree ee tneer eevee i

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i Rs eo ar af eine ion” « 2te meena te ROE i POPULAR SCIENCE MONTHLY Better Shop Methods. How Expert Mechanics Save Time and Labor Short Cuts in Laying Out Machine Work By Joe V. Romig Tool Designer and Builder ANY short cutsare possible in lay- ing or lining out work in the ma- chine shop. Presumably theregu- lar layer-out and the shop foreman know most of them, but the machine hand or floor hand, no matter how much experience he has had in his Fig. 1. Laying particular specialty, often runs out, the hhori- into all sorts of difficulties when The piece is he is called upon to lay out work. It goes without saying that any mechanic who attempts lining out for other workmen must be familiar with the use of machine tools in general and have been “through the mill’’ sufficiently to know just what operations are necessary and their proper order to complete the work in hand. The main problems in laying out are these: To mark and check the work accurately and speedily, and to do it in such a way that the machinists will be able to follow through the various steps without themselves having to check and measure for obscure markings, un- certain checking points, and unindicated fly lines. The layer-out can, indeed, do much to simplify the work of the machinist. First of all, the lines and punch marks should be easily distinguishable. On rough work this*can be accomplished by coating the metal with a whitewash composed of equal parts of lime and powdered chalk mixed with water to a thin paste and spread over the work with a soft bristle brush. On extremely accurate and highly polished tool work, it is more desirable to give the surfaces a coating of copper. _ This is done by e— E applying a so- lution of blue a —_ a | at vitriol and dis- | |’ r = Dp. ictilled water, “ee ae care being taken . — a first to remove | i i 5 all grease and . dirt. The cop- | L ML — | per is easily re- moved after the completion of the work by rubbing the sur- face with fine emery paper or cloth. For laying out, the machinist should become accustomed to having a particular set of tools available at his bench so that he will not have to search through his tool chest after he has started. There should be light and medium weight hammers, dividers from 4 to 12 in., micrometers, Fig. 2. Diagram illustrat- ing layout o ang casting _ trammel sets suitable for both small and then turned for marking the vertical lines large diameter work, with suitable divider and caliper feet and also a set of ball feet for work with holes in the center, and a surface gage. Then, too, he should have at hand an accurate tape line, several scales of different lengths, scribers, prick punches, squares, and a bevel protractor, as well as a center head and other tools. In all laying out, the surface plate plays a most important part. On it the work must be blocked up perfectly true and level. A careful study of the blueprints must be made and the rough dimensions of the work checked to see that no great discrep- ancy exists. If any part of the casting or forging is scant of metal, the lining out must be very true to save the stock. Often when the casting or forging is faulty on one side, the lining out should be such as to take off as much metal on the faulty side as possible. Surfacing Cut Sometimes Necessary In iron castings, where there is plenty of stock -for finishing but the metal ap- pears to have air holes, it is well to have a surfacing cut made first to show how deep the defects are. Since the starting points in laying out a piece of work are the under side of flanges, the outside of bodies, and other surfaces that are not to be machined, these should be checked carefully and all differences should be divided so as to make uniform the thickness of flanges and other parts. Thus in Fig. 2 the dimension A is first checked and estab- lished so that the flanges at the extremi- ties of B will be equal. Then comes the determination of all center lines. The master horizontal center line is scribed all around the work with a gage. If there are a number of bosses, lugs or flat surfaces to be worked to accurate distances from the master center line, their distances are scribed horizon- tally before turning the work, as in Fig. 1. The work is next turned so that the master center line runs vertically to the surface plate. The work is blocked up true as before and a line is scribed across to serve as a reference line from which the remaining lines can be located. On all lines marked out make light center punch marks at short intervals so that if the lines are rubbed out, the punch marks will serve instead. Center punches, it might be added, should be long and slender at the pointed end so that they will not obstruct the view of the lines that are being punched. When a hollow casting is to be machined, it is customary to in- sert a wooden plug and scribe arcs on it from the edges to mark the center. A clearer intersection can be obtained if a square piece of tin is fastened to the plug at the center. This is done by bending over two corners of the tin at right angles to the surface and driv- ing these points into the soft wood. The arcs on the tin will be more clearly defined than on wood. From the center thus established it is possible to run a fly line; in fact, any ex- perienced shop foreman will insist that all machine workers run a fly line on every piece they have to turn. This facilitates the progress of the work after it leaves their hands. It requires but a minute extra when the work is still in the lathe, but saves much time later, as well as in- suring greater accuracy. When in the lathe the line A is cut with a fine pointed tool as shown in Fig. 3. Referring to Fig. 2, the distance E is projected from the previously established See % 1 CHUCK cts 7~ TOOL ee A Fig. 3. Running a fly line on a circular piece of work in the lathe with a fine pointed tool center line. Then the distances D are laid out, giving the center line of the side flange. Such dimensions as C, the thick- ness of the single flange, are neglected entirely when both surfaces_of the flange de@not require machining. While the piece above described is a simple one, it serves (Turn to page 84)

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» worked to ster center d horizon- s in Fig. 1. o that the ally to the plocked up ibed across 1 which the nake light ntervals so the punch d. Center led, should he pointed ot obstruct t are being ng is to be ary to in- scribe arcs » mark the section can > of tin is ater. This ners of the e and driv- rood. The rly defined lished it is ct, any ex- ist that all > on every facilitates r it leaves a minute the lathe, well as in- en in the ne pointed tance E is sstablishéd -_ . circular +h a fine D are laid f the side the thick- neglected the flange e the piece », it serves POPULAR SCIENCE MONTHLY Choose your ‘mike’ CAREFULLY F there’s one tool in your kit that should be right in every detail it’s the Mi- crometer. vs Get a Starrett and you can’t go wrong. Here are some of the features that help to explain the preference of two generations of machin-’ ists for these fine Micrometers. EASILY READ—notice the large Barrel and the- clear-cut distinct graduations. SLEEVE ADJUSTMENT—a recognized triumph in tool design. Easier and more exact than the usual anvil adjustment. IMPROVED RATCHET STOP—a wonderful aid to accurate gaging. STARRETT PERFECTED LOCKING DEVICE—a slight turn of the MICROMETER nut locks the spindle firmly. No. 226 These calipers meet the de- mand for accurate gagesat a low price. Supplied singly or in sets (combinations from 1 to 6 inches) as de- sited, Starrett design, workmanship and finish assure you of a Micro- meter that is not easily sprung, is simple to adjust, and is good for years and years of reliably accurate service. You can’t go wrong on a Starrett. THE L. S. STARRETT CO. The World’s Greatest Toolmakers—Manufacturers of Hacksaws Unexcelled ATHOL, MASS. USE STARRETT MICROMETERS The Starrett Catalog will help you select the Micro- _ meter best suited to your fequirements. Mailed free —ask for No.22 “W" POPULAR SCIENCE MONTHLY

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84 BETTER SHOP METHODS DEPARTMENT OF POPULAR No. 185 Automatic “Mr. Punch.” Length, 10 inches Nall ‘ “ ste, wietcepent BR Acme No. 111 Automatic Screw-Driver Length, extended, 18 inches Give him a tool for Christmas Here are two of the best tools made—for handy men, for men who work with tools, for boys who build things. Each is packed in a Special Gift Box—all ready to present on Christmas morning. The Goodell-Pratt Automatic Drill, ‘Mr. Punch,” bores holes—any size from '/1. to '/¢4 of an inch. In the handle are eight different size drill points. You get the one you want by turning the top cap. Fit the point into the chuck. Then you push and Mr. Punch twists. The hole is made in a jiffy. The Goodeli-Pratt No. 111 Automatic Screw-Driver also turns work into fun. You just push, and the screw sinks in. Three tool-steel blades—hardened, tempered and polished —are included. Ask Your Hardware Dealer These Goodell-Pratt Christmas Gifts are sold by hardware stores everywhere. If your dealer hasn’t them, order direct from us. Price of each tool is $2.50. Mr. Punch says: ‘‘Do your Christmas Shopping at the hardware stores.’’ GOODELL-PRATT COMPANY GREENFIELD, MASS., U.S. A. Galimith GOODELL PRATT SCIENCE MONTHLY Laying Out Machine Work (Continued from page 82) to show the sequence in which the opera- tions of laying-out are to be performed. In general it may be stated that individ- ual parts are usually laid out complete in themselves. When many pieces are to be made alike, a templet is commonly used and the work is done in jigs and fixtures that are themselves laid out to conform to the templet. The templets are made of thin sheet plate. When locating points on the circumfer- ence of the fly line, it is often found that an accumulation of errors caused by the slipping of the divider points and the springing of the legs gives an appreciable difference in location. In fact, if an at- | tempt at division is made by spacing around the circle with consecutive posi- tions of the dividers, no two measure- ments will agree exactly, even though the workman may use extreme care. The better way is to divide the circumference into fours with two lines at right angles through the center and then re-divide into eighths and sixteenths in the same way until the proper locations are arrived at. Often this will not give the proper number of divisions and the start must be with sixths. This can be accomplished by using the radius as a chord on the dividers for dividing into sixths and proceeding as before. A table of chords is given in most handbooks and will be found invaluable in obtaining accurate results. Disks of lead are sometimes used to plug holes so that the center can be marked for scribing lines with the dividers. The disks can be compressed or stretched to fit. Marking Holes for Drilling Holes that are to be drilled are often laid out with two or three circies inside the drill size circle. These circles are punched at several places, as the oil used on the drill dims the scribed lines. The advantage of the extra circles is in show- ing if the drill is running out before it has cut to its full diameter. If it is running out, it can be coaxed back by means of a chisel. Many machinists find difficulty when it comes to lining out large work, for then the piece must be leveled up on an accu- rate surface plate andalevel must, in part, take the place of the square. Be sure that the surface plate is not misused. More- over, the plate itself should be carefully leveled. Plumb bobs are used to level up clumsy work. Cylindrical work is first centered and all other points are squared or leveled from these centers. After this the plumb bob is used to transfer the center to the opposite face. When using’a long straight edge to transfer through the plumb bob to a lower surface, it is good practice to clamp it to the upper flanges. Any straight edge or square is liable to move unless it is clamped in a true and accurate position. Rather than project an angle from a smal bevel protractor with a scale or ‘straight edge held against the leg, lay out the bevel on a circle and divide a quarter 1500 GO OD TOOLS (Turn to page 86) 86 BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY r ee ai:

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| NEw POPULAR SCIENCE MONTHLY — INDISPENSABLE! ines a Vork This Household Guide enables you to select the right Paint, Var- nish, Stain or Enamel for a given purpose. Don’t take chances. ie oO era- 7 ef . . = S ave th is Pa g e for reference with your family, your painter and the individ- Sherwin-Williams dealer. aplete in ; ure to be nly used i > — HOUS EHOLD GUIDE conform made of e e a o e e e For Painting, Varnishing, Staining and Enameling - "cu - Pp i =. TRA an — fe IMPORTANT: Each of the products specified below bears our name and trade mark BS MARE | by the i and the ‘4 TO PAINT TO VARNISH TO STAIN TO ENAMEL reciable Use product named below | Use product named below j Use product named below | Use product named below ‘ S-W Auto Enamel: for the | S-W Auto Enamel Clear: S-W Auto Enamel: assorted f an at-. : AUTOMOBILES ...... man who paints hisowncar a colorless varnish colors - spacing AUTOMOBILE TOPS|| S-W Auto Top and S-W ve posi- AND SEATS ..'...... .. Auto Seat Dressing 1easure- es House Paint: a full oil Old DutchE Rs : gloss utch Enamel: full gloss ugh the BRICK....... sreseseeees SW’ Concrete Wall Finish: for outside exposure Th dull finish e e S-W Handcraft Stain: iference Flat-Tone: the washable, flat Scar-Not Varnish : for wood- perudins for , 7 ] CEILINGS, Interior. .:.6.. oil paint , work only; such as beamed ceil- new hard wood Enameloid: assorted colors angies ings, ete Floorlac: varnish = “a 4 : r combined, new or old woo ide into ; Rexpar Varnish: weather re- -: ‘ Old Dutch panne ; byes, sa Pee Exterior ....«. |] SWP House Paint: sisting, for porch ceilings, etc. S-W Oil Stain: for new wood ep ibe gloss or rub- ve S aris cals e 2 paint, resists weather be with Scar-Not Varnish: gloss Sage a a see hed by DOORS, Interior........ |] SWP House Paint: fi ey _ — yy ge S-W Handcrafe Stain: i Enameloid: assorted colors ee - 1¢: oO i iri i lividers without rubbing Preach cia ding as i Rexpar Varnish: ; ‘ Old Dutch Enamel: white, in most Exterior ...ccces SWP House Paint: — resisting spar S-W Oil Stain: for new wood wy, Sem Atay interior nt . lable in SWP House Paint: FENCES Metalastic(iton or wire only) S-W Preservative Shingle 4 ‘ cvccce eeecesccees S-W Roof and Bridge Paint: Stain ise oO for rough wor : - i int: - ish: Floorlac: ish and S-W Inside Floor Paint: can be FLOORS, Interior (wood)... s © ecm Mar-Bat Rabe mo heel-proof a 2 - the enamel-like finish «nich: SWC Floor Finish: tines Sees fe open coe | Detel tenes trees S-W Porch and Deck Paint: To properly finish woodwork E loid: d ive Scar-Not Varnish: loorlac: rnish. and stain a shite, FURNITURE, Indoors.... poyee Bi 7 inte hard usage i Tonkin’ . P ON Een eee rubbed ren fi g Porch ..... Enameloid: assorted colors i pe weather S-W Oil Stain: for new wood Enomeloid: assorted colors ae i hingle | Old Dutch E I: , often ee oF Saree SWP House Paint: a Eoin oF ay ali cabatlag ney . inside i nee iNet Varnish: S-W Inside Floor Paint: es are LINOLEUM ............ sti ny Stee pao A nie the pattern z the enamel-like finish il used RADIATORS ....+0.-.+ |] $-W Alunaimnem a Gold Enomeloid: sseored colors , The Paint show- ROOFS, Shingle ...... S-W Roof and Bridge Paint: S-W_ Preservative Shingle ° US ER eer Metalastic: _ it has Composition, ...... Ebonol: black coal tar paint inning SCREENS S-W Screen Enamel: S-W Screen Enamel “eee D To keep attractive i int: i lac: - ‘ as of a A aR S-W Family Paint: Rexper Varnichs Floorlacs ‘inside use) a var- | Enameloid: assorted colors Flat - Tone: the washable, flat Old Dutch Enamel: white, when WALLS, Interior (Plaster or oil paint gray, ivory; glossor rubbed r then Wallboard).........- SWP House Paint: E a 4: ’ accu. a full oil gloss nameloid: assorted colors re > ' Handcraft Stain: | part Scar-Not Varnish: tel ye for | Old Dutch Enamel: white, e th t SWPH Pai . bao a 4 wd be rub- new hardw gray, ivory; dull or gloss, ( a : 4 louse int: gloss ‘0 a dull fin ‘3 ; : istocrat of enamels, spec- M aarti eterna Flat-Tone: fiat oil paint Velvet Finish Varnish No. § WS ek wood ted 4 cadena pons a ore- 1044: dries dull without lac: for new or old wood; | Enameloid: assortéd colors efully rubbing a varnish and stain combined 5 lumsy NOTE: Best results can be had Copyright, 1923, wi by following the fully pre- Ns The Sherwin-Williams Co, tered pared directions on labels. cA VL L | lA Mf. IS COVER veled THE lumb = VARNISHES ° aa {i o the “i alm ae | 4 aight Set _ ob to y | a C yas Mark on the ‘‘Household Guide” the particular surface or article you have in : Sen Painting, Varashings sraimeliag of staining problema in your house, not covered By 5 n or staining p x = move the Guide. write = X move extensive Guide will be found at the store of your Sher- urate win-Williams dealer—prominently displayed—a part of service. Write for free booklet B450 with complete Send 50c (65c in Canada) for Household Guide are helpful information Home Painting Manual, 177 pages, = Dm a I ag Re Mpeg er eg gs enameling. aluable whether you do the comple on the 4 ; : t. B. 435. For cheerful, satisfac- For permanence an le or Te “seeew”' dee om work yourself or employ a master painter. published. Address Dep or tory walls beauty ‘i = THE SHERWIN-WILLIAMS CO., 601 Canal Rd., Cleveland, Ohio f arter : TA eee Ae 4 2eeeee eo ae le Oe. eee ee

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Crossroads of Conversation Could the telephone directory in the hands of each subscriber be revised from hour to hour, there would be no need for the information operator. But even during its printing and binding, thousands of changes take place in the telephone community. New subscribers . are added to the list. Old ones move their ‘places of business or of residence. Though their names are not listed on the directory, these subscribers must be connected by the highways of speech with all others in the community. To supplement the printed page, there must be guides at the crossroads of conversation. Such are the information operators, selected for their task because of quickness and accuracy, courtesy and intelligence. At their desks, connected with the switch- boards in central offices, they relieve the regular opera- tors from answering thousands of questions about telephone numbers that would otherwise impede the rendering of service. If they are unnecessarily asked for numbers already in the directory, service is retarded. “Information” stands for the most complete utilization of telephone facilities. “BELL SYSTEM” ‘AND ASSOCIATED_COMPANIES. One Policy, One System, Universal Service, and all directed toward Better Service AMERICAN TELEPHONE AND TELEGRAPH COMPANY A place for every Tool and every Toolin a GERST- NER Case will save both money and Tools. A style size and price to suit all trades. Catalog free. Save Your vents $3 cash Buys Typewriter N\: Ses WRITE at once H. Gerstner & Sons a — bein ae Be 345Columbia St., Dayton, Ohio | Wynn Typewriter Exchange %3 21 Reliance Bide. Laat Wonderful opportunity for men and women. Thousands of appointments now in every city of the country and in Alaska, Porto Rico, Hawaii and the Philippines. Write for FREE CIVIL SERVICE BOOKLET, which tells how to get a position with the U. S. Government. . “~INTERNATIONAL CORRESPONDENCE SCHOOLS WORK FOR UNCLE SAM “The best employer in the world” Good salaries, short hours, liberal vacations. Positions open Box 7667-C Scranton, Penna. ——., Laying. Out Machine Work (Continued from page 84) segment into the number of spaces neces- sary to give the bevel required. Be careful when studying a print to get the right side of any angular work and ascertain whether the angular position is taken from the vertical or horizontal. The first line scribed with a center head should be checked by reversing the head and scribing another line through it. If the head is off or the scale is loose or out of true, a double line will show. The same is true of lines drawn with a square. Parallel lines drawn with other than surface gages or height gages should be projected by swinging arcs from the first line. Finally recheck all layouts with the utmost care. Water Still Cheaply Made for Auto Repair Shops A WATER still is a necessity in auto repair shops and often a convenience in the home. A simple and yet efficient still can be made and used in any place where a source of low-pressure steam can be obtained; in other places the hot-water tanks can be converted into steam generators with but slight alterations. In the latter case a steam line is inserted in the top of the water tank with a low-pressure steam gage and a safety valve that will blow off at 10 pounds. The water is kept below the COLD WATER @@—>>--SAFETY VALVE INLET LOW PRESSURE 3 - STEAM GAGE TO FAUCETS —> ul = “Ss. COPPER : ee STEAM LINE --% Sy 1 // WATER GAGE H WATER x Ti fins 1O-GAL °° rH OILCAN h lt DISTILLED me HEATER WATER fm2".> 35 Diagram showing a typical installation using steam from hot-water boiler | COOLING | WATER INLET line shown in the illustration, its level being indicated on the water gage at the side. The still itself consists of a 10-gal. oilean with the top removed and a copper coil. The steam is led through the coil, where it condenses and the dis- tilled water flows out of the end of the coil, which projects from the tank near the bottom. Cooling water is led into the bottom of the tank and an overflow pipe is soldered to the tank near the top. Any source of low-pressure steam will work well. Steam-heating systems and steam-pressure cookers properly equipped with valves and gages may safely be used in conjunction with this still.— JOHN H. SCHALEK, Pittsburgh, Pa. IN THE absence of borax, powdered glass makes an excellent flux for brazing. Heat the glass to redness, drop into cold water, and pulverize.

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Vork es neces- nt to get ork and sition is ital. iter head the head h it. If or out of ‘he same re. 1er than 10uld be the first with the i for in auto venience efficient ny place eam can ot-water » steam ations. line is ter tank e and a f at 10 slow the AUCETS - a COPPER Coit. f OVERFLOW SOLING ATER INLET lation boiler its level ye at the . 10-gal. and a ough the the dis- d of the ank near led into overflow the top. eam will ems and equipped afely be ; still._— iY red glass brazing. rop into POPULAR SCIENCE MONTHLY Type RB-2 Price $135.00 Announcing a New Paragon Receiver —the Ideal Family Christmas Gift What could be a more wonderful Christmas gift than a radio receiving set that you know is the best that money can buy? Think of the pleasure it will bring to every member of the family, young and old. Think of the happiness it will mean ™ to you every night of the year. PARAGON Radio Receivers are famous as the three circuit pioneers which have proved their superiority by eight years of practical operation. The newest PARAGON, pictured above, is the last word in sensitivity and selectivity. The superiority of this type over all other classes of receiving equipment has been thor- oughly proved by the long list of distance records which it holds. Included in these rec- ords are the reception of the first trans- continental amateur message, the reception of the first trans-Atlantic message, and the unbroken communication which it has main- tained with the McMillan Expedition frozen in above the Arctic Circle. The operation of the new PARAGON Radio Products is yours for the receiver is so materially simplified that even in the hands of a novice it equals in every way the performance of the older type in the hands of an expert. You need only switch on the tubes, set the “ calibrated dial and turn two other dials that automatically give you their proper position for the reception of any given broadcasting station. In appearance it is an addition to any home. All cabinet work is of mahogany with a brown mahogany finish. All metal parts showing, inside as well as outside of the cabinet, are nickel plated. 98% of the wiring is invisible. The whole outfit is compact, neat, solidly built, and finely finished. It is the ideal Radio receiver and the ideal holiday gift. i Dealers: We believe in the pro} distribution of Paragon Radio Products. An illustrated Catalog of Paragon me se oie the sreuee eeee Role dealers, who will arg solicit and serve the consumer in the sale of asking. Paragon Receivers. lf interested, write us for details. ADAMS-MORGAN CO., 18 Alvin Avenue, Upper Montclair, N. J PARAGON Reg. U. S. Pat. Off. RADIO PRODUCTS

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BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY Another Addition to our RatchetScrew DriverLine No. 59 +: es hear people say, “I can’t seem tofindaratchetscrewdriverstrong enough for the kind of work I do.” Maybe you’ve said it yourself. If so, don’t waste time. Stop in at the near- est hardware store and ask the man behind the counter to show you this new MillersFallsRatchet ScrewDriver No. 59. It is made especially for electricians, gunsmiths, mechanics and others whose work demands a screw driver more rugged than the regular type. Same design as our popular No. 63 line of ratchet screw drivers. Your kitisn’t complete without this tool. The more you use it, the better you’ll like it. Specifications : Ratchet Pawls—Tool Steel. Ratchet frame—cold roll- ed steel. Handle—hardwood, high- ly polished. Shaped to hand. Thumb rest at lower end. Diameterofratchet—7in. Length of blade—1%% in. Ratchet springs —spring steel, Blade — highest qualit screw driver steel, hard- ened and tempered. Exposed metal parts pol- ished and nickel plated. Diameter of blade—5{, in. Cabinet type. Length overall—64 in.

Ratchetoperates either to right or left by turn- ing shifter ring. At 0 it becomes a solid screw driver.

MILLERS FALLSCOMPANY Millers Falls, Mass. Manufacturers of Carpenters’ Tools, Hack Saws and Automobile Tools

MILLERS FALLS TOOLS ee TPE SG otal

Tilting Table for Milling Tapers AS THE milling machine has no arrangement by which the table can be thrown out of the horizontal, it is often useful to have a special tilting table for tapered work, such as taps, reamers, and the like. The table should be as wide as the index centers with which it is to be used. By bolting irons to the table, all kinds of tapered work can be done. The angle of tilt is determined accurately by means of a sine bar. If the taper wanted is out

— Le \ WCSEM TILTING en aol

GOR AS WIDE > | TO SUIT BOLTS AS INDEX HEAD a | OR TONGUE IN BASE ee BASE OF INDEX ta Mit ko HEAD a - =i fa be— 3 —o

| 23 SHORTER THAN "FILLING

7 —— ta ee . H “@Q- ree PRR eee 1 By Henry S. Laraby

of range of the elevating screw, one side of the table can be blocked up. The edge of the table has been left clear of the rib usually found on tilting tables; this makes it easier to clamp work to it. Another improvement is the finishing of the under edges parallel to the top. i} : While the table shown here is made with castings, smaller tables are made of machine steel.

u 2 OP t-pah--- nbs ogo se cE Pe T--TRT “Eis ‘5 20| ‘BOLT HOLES’ ra : rs | ieee a SEAR Lye aE — = ‘ ae Mi x9 THDS, | ri SS 8 ry op te tt a INSERTED TONGUES +

TO FIT MILLER SLOT” 6° OR WIOTH OF INDEX HEAD BASE] .« £) § xIITHO) , : 7 eT 25 a TONGUE INSERTED TO) =O TB FIT MILLER SLOT

The tilting table set up on a milling macaine and deiails of the parts

SCIENCE MONTHLY? two subscriptions as follows: be gift subscriptions. POPULAR SCIENCE MONTHLY 225 West 39th Street, New Yorx

A Gift for Yourself WEY not give yourself a year’s subscription to POPULAR You know that’ in POPULAR SCIENCE MONTHLY you will get the most fascinating reading published, and will get it promptly every month delivered to your home. If you also give a year’s subscription to some good friend, we will make a very attractive special Christmas offer. You can have POPULAR SCIENCE MONTHLY delivered to a friend for one year at a cost of $2.50—or even less if you order One Subscription . . ... . ~ $2.50 Two subscriptions only ... . One of the subscriptions may be your own, or both may If you wish more than two subscriptions add $2.00 for each additional subscription. A gift card announcing your gift will be sent to each friend to whom you give POPULAR SCIENCE MONTHLY. Send your order early—use the order blank below or, if you prefer, an ordinary sheet of paper. Write the address plainly. Wor Gees. ... seer

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S evating of the pen left 1 tilting ap work is the ‘allel to is made e made LAR der 1 give blank eerece seeeee eee ee cee eeee

POPULAR SCIENCE MONTHLY ~~ ek 32-Piece sists of 2 Bread Pans om —

No Money Down \ Not a penny now. Just mail the cou yu Kitchen Set—it is FREE. Use both sets 30 days on Free will send you this splendid complete 82-piece Aluminum | Triai, and if not more than satisfied, send them back and we Cooking Set, and aa the Free 10-piece Combination | will refund your ee.” and pa tion both ways. transporta Kitchen Set. When the goods arrive make first payment | If you keep them, for the e iembins Set, a little of only $2.00 on the Aluminum Set. Pay nuthing See the saduth. "Roup the Kitchen Set as a gift from ectaiant Complete 32-Pc. Aluminum Set a | and FREE Kitchen Set 10-PIECE = zee is Hartman’s famous special, selected set of FREE KITCHEN SET eavy fer ge Aluminum Ware—a complete cooking | “note

— ht to handle, easy to clean, always bright absolutely free with 2 A mth ny ge ge o-" plo Will wage chip, crack or rust, So durable Potato Masher Con pees

tee it for life. 32 utensils—everything | measuring Spoon F ro ets for baking, boiling, apes, £ frying. Just } ‘<*

read the list above. You want and need everything | ‘Ail have white enameled handles and hang on there. Yourkitchen o a th — wall rack, keeping them conveniently at hand, really can’tappreciatethissplendidsetuntilyouseeand ee ee ee a ne acoue mn use it. Then a you willrealize what a wonderful bargain HARTMAN beoe eS tie itis. And without aay *s cest_shestately free—you | Sena and t a Combination Kitchen which gives you 10 utensils with white handles—all hung in a row—where you can reach them easily. 22 Foe mim Cosh St No. 1TEEMAT, recs Hartman gives the | Aluminum Set on arrival. Rien Serie E. Nearly a Year to Pay write mms iberal y farasodare ice ink UE no setiadt wil sho bat tecegnd sh rol’ enter aoe erendane mercantey Wes of te Kan Sek ee es it ou only and pos on iva th (Chis on the Aluminum Set—nota penny to pay at any time on the owes SRA SER TON Se Name tchen Set). Then, if after 30 days’ trial you decide to keep it, pay a ioe every month. Take nearly a year topay. Order by No. 417EEMA7, Price for Aluminum Se sane. - No money down. $2 2.00 and postage on arrival.’ Balance $2.00 monthly, 10-Piece Kitchen Set is FREE. | oecapetion anna nner z R. F. D., Box No. a Don’ cto gy Bete, Tees while this offer holds good. pete ie Girest ond Mast... ee ail the Coupon penny’s risk. W. while you can get the Kitchen Set Free | or Street and No.

HARTMA J FURNITURE & CARPET C0. op Recmbrenr sg emma ane atm TT Dept. 5852 fits’, Siac CHICAGO J gena shipment to

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HE Peck, Stow & Wilcox Co. has been making good tools for more than 100 years. These tools formerly branded P.S.& W. Co., now branded PEXTO, are of the highest quality and are FULLY GUAR- ANTEED as to workman: ship and materials. 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 Company Southington, Conn., U.S. A.

BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY

Micrometer Stop for Lathe 4 TERY often it is desirable to control the travel of the lathe carriage within closer ranges than can be ac- ' complished with a non-adjustable stop | fastened to the frame. By constructing such a stop body as shown so that it wi!l hold a commercial micrometer head, and bringing the carriage to a stop against this, it will be found that the limits can be fixed much more accurately. The micrometer head should fit snugly in the hole provided for it, but the tension stop screw should be adjusted so that it REAM TO FIT MICROMETER HEs _ VW) /) Yf LY / ry

A micrometer head clamped to the lathe bed serves as an accurate stop will not bind the thimble and prevent it from revolving freely. The distance between the block and stop body, as well as the notch in the block, should be designed to fit the lathe ways. When the draw screw is turned to the right, the biock is drawn down the 12-degree incine and clamps the stop in place. The micrometer screw can then be turned so that the proper travel limit will be established when the stop screw on the carriage bears against the head. Care must be taken not to bring the lathe carriage against the micrometer with too much force.

Flexible Gas Hesitdine Torch Fok bench use the gas burning torch illustrated has several advantages. Because of the direct connection through a flexible metal tube with the gas line, the torch can be lit more quickly than a regular blowtorch. The flame is adjusted through the spreader and the intensity is controlled jointly through the gas AIR REGULATOR PINNED -” COLLAR,

AIR REGULATOR BRASS ie yy SHEET STEEL‘ FLAME SPREADER Sa For bench use this gas torch gives an easily regulated flame the moment it is lit », WOODEN NGTH OF s. OS *- HANOLE FLEXIBLE METAL GAS TUBING petcock and the air inlet valve of the torch itsélf. The body is a brass tube fitted to a wooden handle with small thimbles. The air inlet is a sleeve fitting the center tube snugly, holes being drilled through both. The flame spreader is made of one piece of steel, as shown.

For Pleasure or Profit Every man has a er from which he derives either pleasure or profit—or bo Through a better job, more quickly, more easily done, the man whose hobby is work- ing in w or soft metals can get more pleasure and more profit from work done on a Boice-Built Bench Machine The Pony Bench Machine shown here combines six machines in one: Saw, sander, drill, grinder, polisher and buffer. It saws 1- inch stock with ease, and does miter- ing, dadoing, tenoning, etc. Easily driv en by 4-hp. or 1/3-hp. motor. Boice-Built machines are in use in thou- sands of shops, both industrial and private. An Excellent Gift for Man or Boy As a gift nothing could be more appreciated by the man or boy who likes to work with wood and soft metals. It will bring years of pleasure and profit to the recipient. Sold on a positive guarantee. Every Boice-Built Machine is sold with a ten day trial money back guar- antee. The complete line of Boice-Built Bench Machines in- cludes larger Bench Saws, Bench Band Saws, Bench Lathes, Bench Drills, Bench Jointers, and Motors. Write today ee! completely descriptive circular on any of these ma- chines, W. B. & J. E. Boice, Dept. P.S. 12, Toledo, Qhio ‘rice without CAuck Pony Bench $3250 Machine

Mads of selected hardwood, fabric ‘evened. vas lined. $imetat size Pies tetera to pier esis, 3 VAC =REE RA Can receive 1C0 miles and more. RUSH ¥oux Dame o learn nth Radio

ta ube ABSOLUTELY FREE dey, fo" Pike Wai Y Co. se Denti” 231 Duane St.,N.Y.C.

Labor, Belt tele mya Celeleh ge | “DETROIT” WIRE HOOK, STAGGERED GRIF BELT LACING Complete outfit including Ip k Time Power, Money ng too post paid §5. Lace bicits for 19 an nct | BT -3 6 fo} 4 ae 31-3 b ae OF: Cel <5 at Ore Detroit, Michigan StopForgetting Make Your Mind an in- dex ox Stet wale you select

Prof. HENRY DICKSON Dept. 929 Evanston, ill.

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es either ob, more is work- and more J ine bines six isher and es miter- ¥4-hp. or -in thou- r Boy y the man ietals. It ‘ipient. oice-Built ack guar- chines in- ‘+h Lathes, ‘ite today hese ma- lo; Ohio uthout cK 19) POPULAR SCIENCE MONTHLY 1 The “A” Battery’s Power in Your Radio Receiving Set THIS IS NUMBER TWO OF A SERIES HE sole purpose of the ‘‘A”’ Battery in your Radio Receiving Set is to furnish current to heat the filaments of the tubes. And this can be done satisfactorily only by an “‘A” Battery that supplies an adequate _ steady current. Anticipating the popularity of the dry cell tube in Radio, and realizing that it required a Dry Cell capable of standing up under service conditions differing from what dry cells are called upon to meet in other fields, the National Carbon Company developed the Eveready Radio Dry Cell specifically for this new use. A dry cell gives its maximum service only when designed especially for the work it is intended to perform. There are for dry cells several uses which are so alike that one type of cell serves for all. This is the field covered by the ignition or general purpose dry cell. The conditions encountered in. Radio are different from the conditions grouped together under the term “general purpose.” And while the general purpose dry cell performs well as an “A” Battery, it was found possible - to produce a Dry Cell “‘A”’ Battery capable of delivering more service on Radio loads. Thirty years of dry cell experience and an immense research organization resulted in the superior Eveready Radio Dry Cell. One of the outstanding features of this special cell is that while it will last much longer when used as an “A” Battery, it is no larger than the standard dry cell. The increased service life of the Eveready Dry Cell ‘‘A” Battery greatly offsets the slight increase in cost; so this battery is not only the best, but it is the most economical you can buy. “‘The Story of Eveready Dry Cell Radio ‘A’ Batteries,”” which tells how to use Dry Cells to the greatest advantage with the vari- ous dry cell tubes now available, will be sent to you free on request. * * * * The “A” Battery gives power to your Radio Re- ceiving Set. Eveready Batteries— especially made for Radio—serve better, last longer, give better results. POPULAR SCIENCE MONTHLY Note: This is number 2 of a series of informa- tive advertisements which will appear in this’ magazine. They are designed to help users get the most out of their Batteries and their Radio Sets. If you have any battery problem, write to G. C. Furness, Manager Radio Division, National Carbon Company, Inc., 1146 Thompson Ave., Long Island City, N. Y. POWER for Your Radio Set Eveready Dry Cell Radio “A” Battery (No. 7111) Directions and wiring diagrams on the jacket tell just how to use this battery with the differ- ent dry cell tubes, This special Radio Cell is also available in two and four cell multiple batteries for receiving sets employ- ing from two to four WD- 11 or WD-12 tubes. Other Radio Batteries Eveready Storage “‘A” Batteries— best suited for fila- ment heating of all Radio Tubes not especially designed for dry cells. The quality storage battery with the long life plates, $15 to $20. Eveready “B”’ Batteries—the life of your Radio. Eveready “Three”? Battery—3 cells, 3 purposes. Manufactured and guaranteed by NATIONAL CARBON COMPANY, Inc. EVEN Radio Batteries —they Jast longer

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The Supreme Insulation RADION Panels are easiest fo drill, saw or engrave with simple tools at home 18 Stock Size ‘Panels Furnished in 18 stock sizes. 6x7 7x21 6x 10% 7 x 24 6x 14 7x 48 6x 21 9x 14 7x9 10x 12 7x10 12x 14 7x12 12x21 7x 14 14x 18 7x18 20 x 24 Radion, being an insu- lation material especially made for wireless use, has the lowest phase angle difference, lowest dielec- tric constant, highest re- sistivity and supreme moisture, gas and acid repelling properties. Send 15cfor sample test piece of RADION pane! 2x3 in. Try it with your own arill. American Hard Rubber Co. 11 Mercer St., New York RADION Panels -Dials-Knohs -Sockets-Insulators C7 & & Be, BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY Extension Arm Aids Draftsman in Drawing Large Work LL draftsmen who have used small drawingboards know how difficult it is to scribe radii, the centers of which are beyond the edges of the board. In such cases a detachable extension arm is a great aid. The device illustrated consists of a clamping fixture and a soft wooden arm. Two pieces of steel with a spacer between are riveted together and a thumbscrew How the arm is used for scribing a large arc, and details of the clamp is used to clamp the fixture to the drawingboard wherever needed. The arm itself is pivoted between the steel pieces by means of a screw and spring washer. The tension should be adjusted so that the arm will remain quite firmly wherever placed.—C. M. WILcox. Direct-Setting Scriber Extends Range of Machinist’s Square B* MEANS of the simple attachment shown, an ordinary square is con- verted into a direct-setting scriber that will be found useful when scratching a center line on work that is strapped on a planer table and in many other places where the work is not easily accessible. The drawing explains itself, but it should be noted that the beveled, cutaway setting edge is in the same plane as the scriber retaining hole. Thus, when the set- ting edge is brought to its predetermined position and clamped by the thumb- screws, the scriber point will be the same ul of. iey 8 tr tod ue DETAIL OF ATTACHMENT \5 - ) « 2 == DETAIL OF ROD PLANER TABLE Readng on scale shows actual height scriber point above table distance from the bottom of the square as the reading on the scale indicates. By substituting a rod milled as shown in the detail in place of a scriber point, the device can be used as a direct-reading sur- face gage, wherever circumstances permit. In difficult locations, when the special rod cannot be used, the difficulties may be overcome through the agency of a com- mon curved point, the contrivance then being used as surface gage. - for THIS MONTH Hedgehog Transformer......... a LS te SE a aaaaeaes “= Battery Test Clips (each) ...... 05 ago Tubs Adanter.....5....... Licensed Neutrodyne Parts .... Rheostats, 6, 25,40 ohm ....... -69 Variocoupler or Variometer , (180 degree) each ........... 1.2 Erla Reflex Transformer...... a aes M urdock 2000 Ohm Phones..... 3.65 Jewell Lightning Arrester ...... 98 Cico Two-way Plug ........... -49 Cockaday Coil, each..... Contact Points or Switch Stops, per dozen....... Special Prices on Tubes, Magnet Wire, etc. Clip this List—Check I Want. Re el ag Tanto Ra Your Order will be Filled by Return Mail Postage Free--Satisfacti on or money back FANS sikdains FREE “The Biggest Little Lathe Built” THE MONARCH Junior Engine Lathe 9-inch Engine: Lathe Here is a sturdy, small engine lathe built with the same quality construction that has made MONARCH Lathes standard the world over. Guaranteed to do any small work any other lathe will do and do it with 1/1000 of an inch ac- curacy. It will fit in any shop or home work room. Easy to learn to operate. Write for Free Catalogue of MONARCH Lathes which are built up to 30-inch swing. ¢ THE MONARCH MACHINE TOOL CO. 401 Oak Street Sidney, Ohio How To Make Things Electrical Have the fun of doing it your- self and save half tine cost This book gives directions for making hundredg’- 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. POPULAR SCIENCE MONTHLY 225 West 39th Street, New York City Price, $1.50 postpaid BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY At rock-bottom prices you get the efficien: sets costing three times as much. Users tell us that Miraco Radio frequency receivers pick up stations from coast to coast. rate either on dry cells or storage battery. lid mahogany cabincte—fineat workmanship throughout. Order direct or send for bulletin. : DEALERS —write for proposition quickly—it’s a winrer. THE MIDWEST RADIO COMPANY Main Street Cincinnati,

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POPULAR SCIENCE MONTHLY a post card— Address Dept. 5-R and we will send you free this 52 page catalogue of radio sets and parts. It also contains explanation of radio terms, map and list of broadcasting stations and much radio information, including ith an explanation of successful hook-ups er. and circuits. ork You will be amazed at the low prices Ward’s quote. A complete tube set S= having a range of 500 miles and more, | including tubes, head set, batteries, and antenna equipment, as low as $23.50. This catalogue contains everything for the expert and amateur. Complete l sets and every improved part for building sets, all the most up-to-date de- | . vices—at the lowest possible prices. 7 - Headquarters for Radio Montgomery Ward & Co. is headquarters for Radio, selling everything direct by mail without the usual “Radio- profits.” Why pay higher prices? Ward quality is the best and the prices will often save you one-third. Everything sold under our Fifty Year Old Guarantee,—Your Money Back if You Are Not Satisfied. Write today for your copy of this complete 52-page Radio Book. cm ig Write to our house nearest you. Address Dept. 5-R Chicago Kansas City St. Paul Portland, Ore. Ft. Worth Montgomery Ward @ ©. The Oldest Mail Order House is Today the Most Progressive t f Et : OS, EE a aD

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ji | nr" 94 BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY Inspect it— point by point Brown & Sharpe Micrometers are made in the largest factory of its kind in the world, from the finest material, by skilled workmen. The highly accurate Micrometer Screw is made on our own special machines. Improved Design is worked out from ac- tual requirements in our large plant. The Spindle fits the hub. The Clamp Ring is a Brown & Sharpe Invention. The Adjustments for wear are the best yet devised—although wear after many years of use is scarcely perceptible. The Finish of the micrometer is distin- guishing and in keeping with the superiority of the Tool. In our previous advertisements we ex- lained three points of Superiority of rown & Sharpe Micrometers. The first of these is the Precision Measuring Screw made on our special machines. The second point of superiority is the Clean Cut Graduations. he first graduating machine in America was a Brown & Sharpe. The third point of superiority is the ac- curate Fit of the Spindle and Anvil testi- fied by the many Brown & Sharpe Microm- eters in use 30 or 40 years and giving faithful, accurate service today. Now we invite your inspection of the complete superiority of Brown & Sharpe Microme- ters, point by point. BROWN & SHARPE MICROMETER CALIPER No. 8 The Standards we use are our own—and obtained from the Government Bureau of Standards. Inspection is exacting—here experience !s again a factor—we made the first micrometer in America. The Brown & Sharpe Measuring Ma- chine is our own product and measures to one-one hundred thousandth of an inch. The Brown & Sharpe Micrometer measures accurately and wears long. Don’t ask for a micrometer—demand Brown & Sharpe. Our Small Tool Catalog describes the com- plete line of Brown & Sharpe Tools. You may want a copy of ‘“‘The Micrometer’’ also—a little text book of valuable information, Write for them today. & SHARPE MFG. CO. Providence, R.I., U.S. A. BROWN Standard of the World. HAND and MOTOR OPERATED 14 Sizes of Machines What it costs to bend pipe our pipe 5 cents ‘ cents 4’° pipe 25 * pipe 10 cents 6’’ pipe 60 cents 8’’ pipe $1.00 eee | WORKRITE| NEU TROFORMER (Licensed under Hazeltine Patent No. 1450080) HIS instrument is made up of one WorkRite Variable Condenser and one WorkRite Neu- trodyne Transformer mounted together. It is correct in every detail. WorkRite Neutrodyne parts will make your set efficient and reliable. Use all WorkRite Parts. WorkRite Neutroformer-____-_--_- $5.50 WorkRite Neutrodyne Trans- 0 Bia Sl RS 2.00 150 KI WorkRite Neutrodon____________ WORKRITE NEUTRODYNE WORKRITE 50 NEUTROFORMERS 9 ff « WORKRITE = NEUTRODONS Panel chart and complete instructions ORDER YOUR KIT TODAY! THE WORKRITE MANUFACTURING CO. 1810 E. 30th St., Cleveland, Ohio Branch Office, 536 Lake Shore Drive, Chicago) PIPE BENDERS Saw Filing Pays Buy a Foley Saw Filer and Setter and establish an in- » dependent, profitable business. Write today for FREE Catalog. Territory open to interested parties. | FOLEY SAW-TOOL CO. 3613 Portiand Avenue MINNEAPOLIS, MINN. The Ideal Gift For Your Radio Friend $15.0 F. O. B. Cleveland Type 6 charges 6 Volt Storage Battery from any 110 Volt 60 Cycle lamp socket at aver- age rate of 6 amperes, or over if battery needs it. Scarcely a gift you could think of will bring more genuine appreciation than the satisfac- tion obtained from an F-F Battery Charger. Buy from your dealer. If he cannot supply you, write for literature or enclose remittance covering express or postal charges on 9 Ibs. IT’S FREE—Write for Bulletin No. 17. The France Mfg. Co. 10417 Berea Road Cleveland, Ohio ; Pioneer Manufacturers of Patented Battery Chargers ro — Ol A ee ee eee aa Extractor Pulls Stubborn Roller Bearing Sleeves and Bushings 3 UREENGS and bearing sleeves can easily be removed from their hous- ings by means of the extractor shown. A hollow threaded sleeve is cut longi- tudinally for three quarters of its length with two slots at right angles to each other. The sleeve is then fitted with a PLATE OVER END OF HOUSING When the outside nut is turned, the threaded sleeve expands and pulls out the bushing bolt, one end of which is upset to form a cone. After the sleeve is slipped into the bushing, the expanding screw is drawn tight by turning up the nut, which bears against a plate over the end of the housing. As the pressure is increased, the threads of the sleeve firmly grip the bushing, which is pulled from its seat. Fluted versus Star Drill ‘T#® star drill is generally used by electricians, plumbers, steamfitters, and other mechanics to drill holes in con- crete, brick, and stone. When it be- comes dull it must be sharpened by a blacksmith who has the necessary dies and dollies. When used by hand, it also An neta eam “ serene A 5 TOOLS TO FLUTE DRILL A typical fluted drill, which can be sharpened easier than a star drill has the objection, to my mind, of requir- ing more force than necessary, because the center cutting edges tend to retard the cutting. A tool easily made in the ordinary blacksmith shop, that will drill rapidly and, I believe, with less effort, is the fluted drill illustrated in detail. The flute, which allows the dust to clear itself during drilling, can be made without dif- ficulty by using ordinary splitting tools. The point of the bit is shaped the regular chisel pattern.—J. C. LAMoN, Alcoa, Tenn. ay POPILAR SCIENCE MONTHLY

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POPULAR SCIENCE MONTHLY 95 ler igs | Can 10Us- n. A MAGNAVOX ongi- nail Products each ith a VERY condition in the art of radio reproduc: tion is most successfully met by Magnavox apparatus. Reproducers R2 with 18 inch horn $60.00 R3 with 14 inch horn $35.00 M1 with 14 inch horn; for dry battery sets . $35.00 the - e , 2 d ls le _ Combination Sets “ has Qik sd AY 4 Ca vOxe A1-R consists of Magnavox ; m fr & = Reproducer with 14inch_ fk % Pipes ead » horn and l-stage Am: ‘4 3 lrawn plifier e e e e $59.00 b a A2-R same with 2-stage >ased, Amplifier a $85.00 ip the sg Power Amplifiers Al-One-stage . . $27.50 od by AC-2-C-Two-stage 55.00 ;. ia itters, Pe ae AC-3-C-Three-stage 75.00 _ by a Radio users will be sent y dies new 32-page Magnavox Rav it also dio Catalogue on request. alo s a + , ee ie ~ said , ‘Magnavox brings you the Uoice of All Christmastide del HE Art of Radio Reproduction is enjoyed by every Magnavox owner. Despite the ever-increasing quality and variety of Broadcast Programs, many a receiving set gathers dust unlamented because of insufficient sensitivity or an .unsatistactory “loudspeaker.” H q : Every Magnavox owner is a master of the art Magnavox Products can be had of good dealers equir- of radio reproduction—the ‘results obtained everywhere. ecause by the use of Magnavox Reproducers and retard Power Amplifiers cannot be equalled with ap- THE MAGNAVOX COMPANY P | paratus constructed in the ordinary way. Oakland, Calif. inary apidly The special attention of dry battery receiving New York Office—370 Seventh Avenue is the set owners is called to the new Magnavox Re- Perkins Electric Limited —Canadian Distributors _ producer M1, illustrated above. Toronto, Montreal, Winnipeg i =|| | MAGNAVOX PRODUCTS re ‘ ee oon There. is a Magnavox for every receiving set 1 SSE... POPULAR SCIENCE MONTHLY 97 a , i

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“‘Red Devil’? Rapid Boring Auger Bits are 33 1/3% easier boring, have 10% greater clearance, and bore with or against the grain of any wood. Style 2400—10/16 in. shown here, 75c. PLIERS 100 Styles—One for Every Need PAIR of “Red Devil” Pliers multiplies by many times the num- ber of useful things you can do about the house, shop, factory, garage. Hanging pic- tures, turning nuts and bolts, mending vac- uum cleaners or sew- ing machines, amateur % plumbing, etc. Forged of steel, and distinctly superior in de- sign. Just a few of the 100 styles shown here. Slip Joint Plier No. 1024 (Shown at =) For all around use. The thin nose ets into tight corners. Sip joint gives wide range to gripping jaw. Wire cut- ter and screw driver add to the number of things you can do with it. Sizes 5% and 6% inches. 6% inch size, $1.00 a pair. Side Cutting Plier No. 50 14 About as useful a tool as 4 any mechanic can own. Powerful cutting edges. The standard electrician’s plier the world over. Sizes 4, 5, 6, 7, 8 inches; 6-inch - size, $1.10 a pair. Combination Plier No. 999 For handling nuts, pipes, wire. Heavy enough for use as a hammer. Ideal for heavy work in_ general. Sizes 6% and 8} inches, 6 \%-inch size, $1.00 a pair. “Red Devil” pliers are on sale at all dealers—ask to see the complete line. The ‘Red Devil’? Me- chanics’ tool booklet is a handy reference guide for users of good tools. Send for it, it’s free. SMITH & HEMENWAY CO.,Inc. Manufacturers of ‘“‘Red Devil’’ Tools 264 Broadway, New York, N. Y. Yq wy ‘Red Devil’ Glass Cutters— the glaziers’ standard tools of - the-world. ‘‘It’s all in the wheel. ; Made in 40 styles. ; No. 024 shown here, } i | How to Make an Improved Die Clamp HIS die clamp, which will hold 12 by 12 in. pieces, is an improvement on the old ‘“‘crab” clamp still widely in use. With the crab clamp, the legs diverge whenever large pieces are inserted, and the leverage becomes correspondingly weak. With the clamp shown, the legs remain parallel, the base of the die rests firmly upon the legs, and a powerful direct pressure can be brought to bear “tie t= 17% i. ia A =le- ie ibs y ei dgnt Ed T © ws ‘ = A 4 + i + ft 3 et 1 lee | ? a: Bt | ee eORM ie AND PUNCH ||. € ef 2? Vania at TAP % x10 THD. | del ae! chet ttle se ek %> pte t | — ie ket es le “he har , « ” ne W% 1% PIN Caen Lo IOUSSTHDS. PIN GROOVEI,™ HOLE-~-1/2> é “2% : Hed gee ket — a %r uta a For large work this heavy clamp is supe- rior to the ordinary “crab”? clamp upon the upper surface at any point across it. The legs are loosely suspended from the cross piece so that the clamp can be adjusted for dies of any width up to the maximum. If made half the size shown, the clamp would be a valuable addition to any machinist’s toolkit for general work. | Expert Mechanics Teli How They Save Labor “I'VE got some excellent shop ideas from your magazine,”’ is a state- ment that appears in one form or | | another in many letters from our | | readers. That is because the best | | mechanics in the country write for Poputar Science Montnury. If you are a mechanic, it will pay you to read the Better Shop Methods Department regularly... The January. issue has ar- . ticles by Laraby, Romig, Luers, Wheeler, Wilcox, Wicks and others, whose names are sufficient to guarantee the value of the material. Loud Speaker Radio Satisfaction True enjoyment of Radio begins when you and your family can sit comfortably in your living room and listen to all broadcasting reproduced in Clear, Full Volume. No annoying rattles, no harsh vibra- tions, no need for constant adjusting and fussing. Morrison Loud Speaker gives-you that kind of Radio satisfaction and pleasure, when attached to either your Phonograph or Horn Attach the Morrison Loud Speaker to the tone arm of your phonograph—takes only a moment—and you have the benefit of the excellent phonograph sound box. Or attach it to any horn. A little dial on the back of the Morrison Loud Speaker adjusts the tone from soft, mellow notes to full-volumed, clear notes. : There is nothing to get out of order. Any one can us2 this wonderful radio unit with the same perfect results as an expert. Satisfaction guaranteed—or your money back. Price complete with 5 foot cord el $10.00 he a $15.00 Order from your dealer, or send direct to us if your dealer cannot supply you. DEALERS If you are interested in one of the fastest-selling Radio units on the market, write or wire for our proposition— it is interesting. Write for Illustrated Catalog. MORRISON LABORATORIES, Inc. 341 Jefferson Ave., East Detroit, Mich. The Wireless Experimenter’s Manra! E. E. Bucher _y HIS book thoroughly coy- Bers the entire field of «ma- teur radio work, includin, the theory and design of amateur wireless transmitters and re- ceivers, the construttion of transformers, high v6ltage con- densers, spark gaps, aerials, masts, arid receiving sets for long and Yhort wave recep- tions. 3309 pp. Fully illus- ePrice $2.25. | Practical Amateur Wireless Stations This book contains best sug- gestions of thirty-three experi- menters on buildigg, installing and operating experimental stations for radio communica- tion. * Profusely sllustrated..-.137. pp. PRICE 75¢ POPULAR SCIENCE MONTHLY 225 West 39th St. New York City, N. Y. BETTER SHOP METHODS DEPARTMENT OF POPULAR SCIENCE MONTHLY

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J ollo Boys]

t sug- »xperi- talling mental unica- 37. pp. INTHLY k City, N. Y.

POPULAR SCIENCE MONTHLY 97

~ LOTS OF TOYS OYS make wonderful models of bridges, cranes, derricks, wind-mills, skyscrapers, railroad signals, Ferris Wheels and machinery. Erector is not only the best fun in the world Gilbert Erector is hut it is splendid training. the only steel Construction To ‘ . ‘ sear Gallas This famous Construction Toy will square Girders delight any boy this Christmas Erector is the only actual structural steel toy. Every part is scientifically proportioned and correct in design. The boy who owns Erector or any other Gilbert Toy is made a member of Gilbert Engineering Institute for Boys, without cost. He can win valuable prizes, degrees and diplomas in this great Fraternity of American Boys. THE A. C. GILBERT COMPANY 222 Biatchley Avenue, New Haven Conn.

= ei salience a

THE A. C. GILBERT CO. 222 Blatchley Avenue, New Haven, Conn. Send 10c to-day for Gilbert Year Book for 1924. Chock full of inter- esting articles for boys, chemical experiments, athletic sports, tricks, useful items any boy can make, story of great engineering feats, etc., as well as a complete catalogue of the many Gilbert:Toys. ; Enclosed find 10c. Send me Gilbert Year k for 1924. Gilbert Erector No. 4 THE most popular set. In addition to hundreds of parts it contains a sturdy Electric motor to operate cranes, draw bridges and machinery models.

Name....... ’ SII nso xnrek vase ; ee ta ae eR ee ae tS PS AE aN CR Oe @ 2 28 © 2.e@ Bee @ eee @& 22 eee"

POPULAR SCIENCE MONTHLY- — a ont. e<4

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In Gift Boxes Almost any man or boy will be glad to get a “YANKEE” Tool for Christmas; and it is exactly the gift to make a mechanic happy. For quick screw-driving, a man needs the “YANKEE” Spiral Ratchet Screw-driver o. 30. (Ilhustrated.) To bore holes he wants a “Yankee” Automatic Push Drill No. 41. For work on his car give the motorist a “YANKEE” Rat- chet Breast Drill No. 1555. Makes easy work of jobs that other drilling tools won’t do. Does he build radio sets? “VankEE” Ratchet Hand Drill No. 1530 is just the tool he needs. Anybody who works at a bench will value a “YANKEE” Vise No. 1992. Swivel base. fa Then there is the“ YANKEE” Tool Set No. 100—a full set of screw-driving tools, with attachments for drill- ing, etc. Solid oak case. SID, See the “YanxeEe” Tools in Christmas Boxes, atyyour:-hardware dealer’s. He will help you in your selection. “Vankee"’ Tool Book.sent free on request. 6 AM % NORTH BROS, MFG. CO., BhHadelphiia, U. S. A. “YANKEE” TOOLS Make Betliv hant “io die ,base is of the swivel type. A Making a Height Gage Base for a Vernier Caliper A SUBSTITUTE for a Vernier height gage, which is one of the more ex- pensive small tools in the shop, can be made from a Vernier caliper. All that is ‘ necessary is a firm base and a scratch blade. The base is tool steel, hard- ened and ground. Its length should be pro- portioned to the size of the caliper jaws > to insure stability. The base is fixed to the sta- tionary jaw of the caliper with a tapering clamp, as shown. The screw that draws down the clamp must be located exactly in the center of the base. The scratch is clamped » to the movable jaw with “ the point projecting well beyond the end of the base. VERNIER 1) CALIPER / SCRATCH STRADDLES CURVE OF JAW r—| BS RUNOUTS ‘ i N \M‘BC?C?—7HW PR “ LU il How the scratch point and base are made and attached to an ordinary Vernier caliper \ Flat Face Vise Fixture Is Useful in Filing Thin Work , ? FILING thin parts of brass or steel, the vise fixture illustrated, which is used by a Washington, D. C., mechanic, is a distinct aid. It is simply a flat steel plate, with a vertical extension to be gripped in the vise jaws. Several deep- oe TEEL PLAT a © STEEL PLATE an The work is fastened with C clamps toa table held in the vise ' throated C clamps are used for fastening the work to the face of the rest. The work is turned about as required to finish any part of the face either by shifting the clamps or turning the vise about, if 29%, size for the flat plate for average use is 6 by 10 in. Pieces - per - Hour Tell You Straight Are you getting ahead with the practical development of your machine? : Are you getting larger pro- duction with each change in design or working adjust- ment ? Is the operator of the machine getting his methods down fine? Your answer lies in the number of pieces per hour—recorded al- ways reliably by 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 wit!i from four to ten figure-wheels, as quired. Price with four as tlle trated, $11.50—subject to discount. (Cix/ less than V% size.) Set-back Revol/is,, Counter of similar model, $10.00 (lis: ThissmallRotary Ratchet © «\:::ter (No. 6) counts reciprocating 1 of the lever, as required ‘« :nallmachines, When the lever J is moved " 7 through an angle of 40 to 60 degrees, the counter regi ters one. e further the lever is moved, the higher the number registered. A complete revclution of the lever registers ten. This coun- ter can be adapted to no end of counting urposes, by regulating the throw of the ever. Price, $2.00. (Cut nearly full size.) Small Revolution Counter, also $2.00. Ss 0" Everything you could ask in a counting device is shown in the 80-page Veeder booklet. Ask for this fine free book. The Veeder Mfg. Co., 44 Sargeant St., Hartford, Conn. —— | a (iirc it! gy a j Lor PODTFI ap CIBPAIS YC AsMATPRrY i Pie 4 a =] Ae

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t FR a ong 1 Gee How three IHREE boys sat disconsolately on the edge of the pond back of the old mill on the Jenkins’ place. All week they had been building a rail- road in the sand along the banks. They had leveled, and dug, and built up until they had the bed laid for a whole transportation system. There were grade crossings, and bridges and freight yards and even a tunnel. While along the edge of the pond Wally had built docks and ferry boat slips. But as Bob said, ‘“‘What good is a railroad without any cars?”’ “Why all the gloom, men?” said a pleasant voice behind them. The three boys locked up to see Mr. Jen- kins, Bill’s father. Bill explained the lack of “rolling stock’’ for their railroad. ‘Well!’ said Mr. Jenkins, ‘‘Why don’t you fellows chip in and get track and trains? In New York,‘I’ve seen some beauties that operated by electricity. They were exact duplicates of the big ones that run‘on the Central.” “Chip in?’ asked Wally, showing empty pockets, ‘‘Chip in what?” “My golly!’ said Mr. Jenkins. “Anybody’d think you fellows were cripples. When I was a boy, if I wanted anything bad enough, I just went out and earned the money and got it. I know Bob there could make some money if he’d saw that big pile of wood I saw yesterday out in the back of his Dad’s place. Wally can. pick the apples down in the orchard and I’ll find something for Bill to do. Get busy and see what you can earn. And then I’ll tell you what I'll do! I'll give you a dollar for every dollar you earn. How’s that, fair enough?”’ “Oh boy!’ Bob cried. “Let’s see that orchard,” said Wally. “Let’s go!’ shouted Bill, getting up in a hurry. First meeting of the R. W. & W. A MONTH Iater, the first meeting of the R. W. & W. Railroad (R— Robert, W—William, W—Walter) was held. Mr. Jenkins collected the money the boys had earned for the railroad. Wally had seven dollars, Bill eight and Bob ten. “That makes twenty-five dollars,” announced Mr. Jenkins. ‘‘And now, as I said I would, I’ll match your capital with the same amount.”” He took two new ten dollar bills and a five from his pocket and put them with the boys’ money. “Total capital of the Railroad—fifty dollars.” *‘And now, gentlemen, if you three will meet me tomorrow morning early, we'll all go into New York on the eight o’clock and purchase ‘rolling stock’ for the railroad.’’ They buy “rolling stock’’ WHAT A day those four had in the city! POPULAR SCIENCE MONTHLY - boys built a railroad Mr. Jenkins took the three boys down to the Ives Display Room in the Fifth Avenue Building at Madison Square. On great tables, which ran all around the big display room, were complete railroad systems. Powerful electric engines, perfect models of their big brothers on the Central, thundered along with mail coaches and Pullmans. A freight engine rumbled by, pulling a long line of flat cars, tank cars, and cattle cars, and in the rear a caboose. The boys looked on wide-eyed .and noticed that each car was a perfect model of the real thing, even down to the monograms on the cars, which showed the cross of the Santa Fe, the seal of the N. Y. C. & H. R., the red and white circle of the Canadian Pacific. There were semaphore signals, which showed red and green lights. Cross- ing signals that rang a warning bell as the Flyer approached. Trestle bridges, tunnels, freight and passenger stations, telegraph poles and street lights. In fact everything that you have ever seen in a big railroad. There was a shriek from Wally. “Oh boy! Look at these.’’ He had found a big table on which were ocean liners, freight steamers, submarines, tug boats and racing yachts. ‘‘Gee! Couldn’t we have some ships, too?’’ ‘*How about it, boys,’ suggested Mr. Jenkins, ‘‘couldn’t we make Wally Captain of the Port and let him handle the ocean transportation?”’ Everyone agreed to this and Wally, with the professional eye of a sea cap- tain, picked out a liner, a tug boat for hauling freight, and a diving submarine for harbor defense. The grand opening A WEEK later, down behind | .. « mill, there was a scene of ten -ite- On November 30th, at 8:30 P. M., Mr. H. C. ep wi "7 sive radio talk. “The Fun of Playing with Trains,”’ Station W.E. / *. -, Wavel .gth, 492 meters. POPULAR SCIENCE MONTHLY ment. Lined up on the bank were Mi and Mrs. Jenkins, Molly—Bill’s little sister. Ambrose—the colored man who cut their lawns, and Rags, the dog. Bob knelt on the ground beside a switch. Wally fussed with the moor- ing ropes of a liner which rode proudly beside her pier. Bill fastened an Amer- ican flag to the halyards on a pole. All along the bank, ran the new rail- road’s tracks, gleaming in the sun. The semaphore signals showed “Clear track ahead.”’ ‘‘Ready!’’ cried Bob. ‘*Ready!”’ answered Wally and Bill. Rags barked. Mr. Jenkins waved his hat and Mrs. Jenkins her parasol. Am- brose clapped. Molly shrieked. Then Bob turned the switch and out of the door of the old mill rolled the Flyer, headlight gleaming, parlor cars lighted. Along the bank it flew, round curves, through tunnels, over bridges. Then came a long freight loaded with lumber and gravel for ‘‘overseag.”’ Down to the water front it went and there stopped alongside a pier. ‘ **How about the R. W. & W?”’ shouted Bob. **Yea!’’ hollered Bill'and Wally and Mr. Jenkins and Ambrose. Suddenly little Molly began to cry as though her heart would break. ‘“‘Why, dear, what’s the mat*cr?” asked Mrs. Jenkins. “I wish I was a boy,’’ sobbed Molly. And after all you couldn’ t blame her much—could you? - oe ee oe ee ee ee ee ee ee ee ee oe oe oe oe THE IVES MANUFACTURING CORP. +& 205 Holland Av: Bridgeport, Cona. | tT «close 10c for which please send me ! , >. ew smashing 28-page book shes shows how to build an Ives Railroad. vo will also tell me about the Ives Fleet i oO l NOM ..cececceccecccccsccoverseesseerese 4 i DAE, von cnewcececeetsowete eeeeeeeeee Q i CHEF... oc ce rccccsccesve State...... eocee t

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designs. rugged than any other. Wrenches *.Tools ON’T senda boy to doa man’s work—or an inferior wrench to tackle a nut or bolt that’s hard to handle. Make sure that the wrench or tool you select for that difficult job is a Mossberg. Each Mossberg Wrench is designed and built for a particular job—and the Mossberg idea is to have that wrench do the job a little better Hence the use of chrome manganese steel throughout the entire line—the one piece, solid construction of the majority of Mossberg Wrenches—the exclusive Ask your dealer to show you Set No. 1900—three socket wrenches with twelve openings. construction of wrenches—they are typical of the Mossberg line, in economy, strength and simplicity. Note the these Lamb Street, *“*Four-Way”’ Socket Set Attleboro, Mass. POPULAR SCIENCE MONTHLY The Home Workshop, Continued How to Rebuild a Broken-Down Car By Ray F. Kuns Principal, Automobile Trade School Cincinnati, Ohio HE frame of the old car again is suspended from the springs. The wheels are again on the axles. The transmission system is installed again on its bearings, and the engine, separated into its component parts, is lying on the bench. Before reassembling the motor, look carefully at each part. Allow no worn bearings, bent valve stems or other de- fective elements to escape your attention. First of all, get a new set of gaskets to replace the old ones. Look at the oil lines and the oil pump to see that there are no obstructions. Then replace the valves, taking care that they are put into the block in the same order in which they were removed previous to grinding. The intake valves must fit the guide well in order that there will not be any leaking of air into the cylinders. The valve guides should be inspected and repaired, if they are found too loose. Now for the pistons. If you have had to rebore any of the cylinders, make care- ful measurements of the new diameter. Piston rings about .005 in. oversize should be selected and at least the two top rings should be replaced, for heat and wear un- doubtedly have reduced the tension of be clearance with a feeler gage while tting piston ring into place the old rings. Be sure that all parts are covered with a film of oil before being replaced. Broken or worn valve lifters should be replaced with new ones, as they might become a source of much trouble. If the valve has worn a hole in the top of the adjusting screw, reface the screw on a grinder so that measurements with an adjusting gage can be made. An important point to remember is that the timing gears must be replaced in a definite position. If you have followed the directions previously given, you will have the gear marked. The flywheel markings will assist in checking the setting of the timing gears. You will now have the engine complete and setin the frame. The next step will be the addition of the accessories. Inspect the carbureter float for leaks by placing it in boiling water. A hole will be easily discernible. If there is some liquid within, punch two holes in the Ready for the Road This is the last of three articles telling how Mr. Kuns rebuilt: the 1918 roadster six shown above. It cost $75 and the materials for repairing it, including paint, top, and tires, totaled $135 float, drain off the gasoline, and solder the holes shut. A cork float, if very old, may have become soggy. Test its floating qualities before putting it back in the carbureter. The vacuum tank float must be ex- amined in the same way. Scale will sometimes form at the bottom of the tank and dirt may lie loosely near the outlet. After cleaning the parts and.seeing that the valves work easily, assemble the tank, being sure that the gasket is good and the tank airtight. Wash out and clean thoroughly all gasoline lines and the main supply tank. Run a fine wire through all small nozzles and passages to remove any obstructions that might be there. The gasoline system should then be clean from tank to cylinder. Put it to- gether and start on the ignition system. Dismantle the generator and inspect the wiring and other visible parts. See that the brushes are in good condition and £ a = si DN 2 ants oe The engine partially reassembled after the worn parts have n replaced and the whole thoroughly overhauled : replace any that are not good. In making replacements, be sure that you sand them in to fit the surface. See that the insulation is not worn out at any point. A bit of tape added here and there will help. J It may be necessary to remove the commutator, turn it on a lathe, and cut the mica between the segments down 1/32 in. below the surface to prevent the brushes frem riding on them. This can. -be done with a hacksaw blade. Then ‘(Turn to page 102) LISYAsLE WOOP LHCII MnO PAPTAALATT ME NMMFITIE AM CMFEATSOR aewsrrarvrrrry «ur

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ng ter she ng ar the , may ating n the e@ ex- » will » tank utlet. + that tank, i and ly all tank. ozzles ctions en be it to- rstem. ct the 2 that 1 and t you e that t any e and re the 1d cut down nt the is can: Then Lionel ‘‘Multivolt’’ Transformers give unlimited power at very little cost. They are best for operating Lionel Trains. Safe— efficient — economical. Insist on Lionel Accept No Substitute POPULAR SCIENCE MONTHLY RIGHT and early Christmas morning you and your boy will be running his Lionel Train, en- joying the thrills of the world’s most fascinating and educational toy. Lionel Trains and Miniature Rail- road Equipment are exact reproduc- tions of those used on America’s leading railroad systems. Lionel Locomotives are powerful enough to haul a train of twenty or more cars around curves, through tun- nels, over bridges and across switches. The realistic Lionel equipment in- cludes Crossing Gates that automati- cally lower as the train approaches and raise as it passes by. Electric Block Signals flash ‘“‘Danger’” and “Clear Track Ahead,” while Electric Warning Signals ring at the crossings. All Lionel Locomotives, Cars and Accessories are of steel construction THE LIONEL CORPORATION 48-52 East 21st Street Dept. 15 “Standard of the World’”’ Since 1900 Merriest Christ ae of Al and practically indestructible. For 23 years Lionel Electric Trains have been electrically and mechanically perfect and fully guaranteed. They are attractively finished in rich enamels and baked like automobile bodies. You can buy a Lionel Electric Train Outfit for as low as $5.75. Or your boy can start his Lionel Railroad System with a larger locomotive and track and add to it. A Lionel Outfit is good for years and years of fun and happiness so there is real economy in buying it. Lionel Trains can be operated from any light socket with a Lionel ‘“‘Multivolt” Transformer —or from dry cells or storage batteries. You can see Lionel Trains in operation at the best toy, hardware, electrical, sporting goods and department stores. Send for the new 48-page Lionel catalogue— a handsome book showing the complete line in colors. It’s free. New York City HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 102 101

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134 102 HOME WORKSHOP DEPARTMENT OF PGPULAR SCIENCE MONTHLY ‘the best book I've ever read on wood boring tools’’ “Tt contains the very information I’ve often wanted, but didn’t know where ‘to get. Your complete de- scription of bits and augers and the simple explanation of how and why they “‘bore,” have made plain to me the reasons for the birth of the Bor Family.” The above is only one of the many unusual comments received on our new catalog. In fact, it is more than a catalog—it is a practical working manual on the selection, use and care of bits and augers. If you haven’t a copy, write today, giving name and address of your hardware dealer. To Hardware Dealers: You, too, should have a copy of this book. If you haven’t received it, send us your name today. Address Dept. 112 The Irwin Auger Bit Co., Wilmington, Ohio Originators and sole manufacturers for more than 30 years, of the Genuine Irwin Bits and Augers. The IRWIN Bit Reg US. Pat Office How to Rebuild an Old Car. (Continued from page 100) see that all bearings are in good condition and put in a good supply of grease and oil before reassembling the generator. Test the generator with a battery to see whether it will run as a motor. If this works, it is reasonable to assume that it will work as a generator. ning on the engine, the third brush can be When run- set and other regulations made so that an amperage of from 10 to 14 is obtained on @ 6-volt system and from 5 to 7 on a 12-volt system. In the same way inspect and repair the starting motor, but do not undercut the commutator. If the ignition is of the battery type, inspect the distributor, coils, and other parts, testing each carefully. New points The carbureter taken apart, ei and inspected, ready for reassembling are frequently necessary on the distribu- tor, but if they are only pitted, they may be honed or ground down to a new and true seat. It is well to renew all high and low tension wires, as the added expense is negligible as compared with the in- creased efficiency of the system. If a magneto is in use as a source of ignition, it should be completely dis- mantiled and all brushes and moving parts ‘carefully checked. The points on the breaker mechanism of the magneto are platinum and very expensive. They are also softer than the tungsten used in battery distributors and are easily filed to a new seat. Test the reassembled — to see that it will generate properly. To do this, run a wire about the terminal screws on the distributor board and back to within Y in. of the frame of the magneto. When twirling the rotor by hand, a spark of sufficient intensity to jump the gap should be pro- duced. Now con- nect all wires from genera- tor ormagneto to spark plugs and call the ignition system finished, for the battery is something that cannot well be repaired at home. It should be sent to a battery shop for recharging before being installed in the car. The water pump, as a rule, does not require much attention, excepting that (Turn to page +i The engine timing gears HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Coal too High? Science Says’ ‘Burn Free Air’ New Discoveries Make it Easy to Keep Homes Warm in Coldest Weather No more paying exorbitant prices for coal. No more hauling and chopping wood. No more shiv- ering in wintry weather waiting for fire to be built. Wonderful new device Nu-Heat takes one part of coal oil, or kerosene (the cheapest fuel known) and combines it with TWENTY parts of air (the only FREE fuel). Makes a cheaper gas than city gas. Gives : as intensely hot, cheerful flame almostinstantly.Warms the largest rooms on *“plizzardy” morn- ings in a few minutes, ROOMS WARM IN 5 reg send steady heat for perfect baking. Fits an: stove, range or furnace, Stop handling coal | wood and cleaning out ashes, dirt, dust and soot, vernment Experts and Domestic i nares as. you haverange,heater, Wade Hill Mfg. Co. Dept. Z41 St. Louis, Mo. Statement “ the Ownershi; » Seanamemens, Circulatio: etc. the Act of ugust 24, 1912, of Sopular Science re ubiiahed month monthly at New York, N. Y., for Octo 923, te of New York, County of New York, ~~ Be and for the State and county person ap- O. B. Capen, who, ha duly sworn ac- t he is the Business Science Monthly and that the following is, to the best of his knowledge and belief, a true statement of the o' apa etc., of the aforesaid publication for sh le we above > caption, required by the Act of A 443, Postal Laws an printed on the reverse of this form to wit: a Bd. the names and addresses of the publisher, e‘lito r aneens —. and business managers are: Pub- lisher, The blishing Compeny, Inc., 225 West Thirty-ninth Street New Yor! Editor, Sumner N. Blossom, 225 West ipNirty math Street, New York, N. Y. M Editor, Sumner N. Blossom, 225 West Thirt; ninth Street, New York, N. Busin' Ak, oO. B. Capen, 225 West Thurty-ninth Street, New York,'N. Y. = Com the evans ae waned ‘opular ng Com Py, ne. York, Nv Y ¥,_ Stockholders of Popular | Science Publishing fore AY > Siery public, in aa oe . bondholders, mortgagees, other security holders owning or holding 1 per cent or more of the total amount f S . — —- ori — paragra next above, names of the owners, stockholders and security holders, if any, contain not only the list of stockhold security holders as they appear upon_the coe of 4 company, but also, in cases where the security a appears upon the books of the company hol that of a bona Treason to believe person, association, or corporation has any interest direct or indirect in the said stock, bonds, or other securities than as so stated by him. (Signed) O. B. CAPEN, Business Manager. Sworn to and ubscribed before me this 19th day ‘of September, 1923. Paul M. Bone. (Seal) My Commission expires March 31, 1924. than fide owner; and this affiant has no SPORT BODIES for FORD and CHEY. 4s0at § J s Vv Vv nm = oa oe tet oS & 2 oh ot

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: HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 103 ? How to Rebuild an Old Car (Continued from page 102) : occasionally it may be necessary. to re- 99 place the packing. Back off the two nuts and replace with new pump packing. Also see that the paddle is not loose on Keep its shaft " . L No The painting should be carried on at Shiv- the same time as the assembling so as to a ae give the several coats ample time to set. t fuel Each unit should receive one or two coats ) of gray or black enamel. Then the body ) as should be placed where dust cannot settle on the soft painted surface and rubbed down thoroughly with No. 00 sandpaper. Flow one or two coats of good body enamel. The toy and curtains should be given a coat of top dressing and the leather upholstering should receive a coat of seat dressing. It is a good plan to loosen the covering, webbing, and padding and stretch all parts tightly if the top is not

‘sapona too worn and can be used again. The al and i soot. advise -Gas, . top e air. VE one or free tion if Co. » Mo. aotien, ' ~ ainsi ar Th * ddi d bbing of h bile, tn pent re adh: aa coal ae pov: Be * Tn ac- at the surplus material can be cut away and the elief, a ° ° ste., of edges bound with new gimp and welt, held mm ote : in place with new tacks. ations, With the car completely assembled, the ' ~~ first thing to do is to see that all cotter 5 West keys are secure and no parts have been ta ; ner N. N.Y. left off or are loose. Then put a man on "OB. the crank and another on the starter. Sad: Be sure that there is a sufficient supply nen of good oil in the crankcase before start- - , Ne ing. If the engine starts, but splutters n, 683 and coughs, do not be too alarmed, for ° Toe a little running will take that out of the The compact, convenient and Se Oe | secs lh ee hence oe complete Portable Typewriter. none. ° ag the the air intake of the carbureter so that Sold by over 3,000 dealers and rs and the piston and upper part of the cylinder R . b h < will receive proper lubrication. emington ranches every- —— If the oil pressure gage on the dash steo ts shows no pressure, prime the pump after where. Easy payment terms van stopping the engine, ‘TGA Fun cold if desired. Send for our illus- a water into the radiator, drawing off the i bons warm water through the bottom petcock. trated For You—For Every- te Continue to run the engine slowly for 9 af bonds, about two hours with the water running body « Address Department 6/ sncew. an through the radiator. Shoot a little oil day ‘of through the carbureter occasionally. If

the engine seems exceptionally stiff, place ¥ . a quart of lubricating oil in each 5 gal. We believe we make the best typewriter ribbon of gasoline for the first 300 to 500 miles. in the world—and its name is PARAGON Do not drive over 25 miles an hour for at least 500 miles and replace the oil at the end of the first 100 miles, again at the end of 250 miles, and thereafter every 500 or 700 miles. e ‘urea wees! Kemington Portable directions given in the last two numbers of POPULAR SCIENCE MONTHLY, you

CL or as FeO AOR GEIS sly i «

should have a first class, reconditioned ‘ P q car that will serve you well for another Remington Typewriter Co., 374 Broadway, New York 1 | 25,000 miles.

WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 105 HOME

, 4 SS | eo ee memeanpme ae aaeE-lC( LT Lh

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el 104 DELIGHT Your Boy Xmas Day with a genuine U. S. Combination Phone and Buzzer Set Every boy will be delighted with this in- strument. He cen learn the Radio code with the tele- § stretch- in a ~ wie to $12.50 his neighbor’s house or into another room, practice with his friends, The phone trans- mitter for voice is equal to any phone made and is combined with the buzzer telegraph sending set, using the same wire. The in- strument was used by U.S. Army in the war. The ones we are offering have never been used, Light weight, with carrying straps for Boy Scout camp work, Schools, etc. All you need*is a 322 Burgess Battery and some wire, These instruments cost the govern- ment over $50.00, yet we are selling them for $12.50 each. Order two for complete set. Complete Telephone Instrument a? These are army $50 Field tele- value e hones, never Ravine been used, made by the Western Electric Co. for receiving and transmitting. They couldn't be built for $50.00. For homes, between house and gar- age, or on the farm, for mines, lumber camps, schools, churches, lodge rooms, office and fac- tory use, for contractors—any place where wire can be run over your own property, this instrument will prove of untold value. The material and workmanship have passed govern- ment inspectors; there is nothing better; the govern- ment sold them because the war was over. Here is heya opportunity. The leather case alone is worth $12.50 Easily moved about. You can-install several phones on one wire and ground, or two wires if you prefer; can be used with either dry cell or No. 703 Tungsten Flashlight Battery. Nothing to buy but battery and wire. Full instructions with each instrument at the unheard of price of $12.50 each. Order two for complete cet. Get your friend to buy one and hook up with yours. Both these items are sold on a positive guarantee of your money back if you are not satisfied. The supply is limited and we cannot get more. Sent C. O. D. if desired. Orders will be lied in order received. Financial Reference, Uni- versity State Bank. J. J. WATSON & CO. 640 Hearst Building | CHICAGO, ILL. = peremcamresicee eo oo RTL AT 106 cgnee Will Save Time and Money B* TAKING one simple precaution, the home worker can insure his var- nish finishes lasting a long time in their original clearness and beauty. Just brush a little denatured alcohol on the wood be- fore the filler or varnish is applied. This will ‘‘kill” any possible bad effects caused by albumen and thus lengthen the life of the varnish. The albumen content of a wood is the chief source of trouble in the disintegra- tion of varnishes. An open grained wood contains far more albumen than a close grained specimen and therefore a varnish lasts for a greater length of time on a close grained wood. Since some of the shellacs, substitutes for shellac, as well as certain varnishes and some fillers contain free alkali in the form of potash, this potash, on coming in contact with the albumen, forms a white, brittle compound that has a destroyihg influence. For this reason, if for no other, only the best varnishes on the market should be bought. In removing varnish from old furniture, however, the presence of al- bumen.in the wood and in the oil sometimes used in compounding finishes, isan aid. It makes possible the softening and easy removal of the varnish by potash, sodium carbonate, and other alkali. All that has to be done is to dissolve one of these substances in water-so as to make a strong solution and then soak the var- nish thoroughly with the aid of a rag or sponge. After a few minutes, the varnish will be soft enough to be easily scraped away with a blunt knife or scraper. Oak sometimes gives trouble because it contains tannin, a very active substance that has a softening effect on some var- nishes. It has good points, however, when certain types of water stains are used. The softer gums and, to some ex- tent, shellac seem to have a softening effect on woods containing tannin. A teaspoonful of potassium chromate, an ounce of which is usually sufficient to keep on hand for all purposes, dissolved in a pint of water is an excellent yellowish brown water stain that is quite lasting when brushed on oak, walnut, mahogany, and other woods containing tannin. But this stain can not be used on pine, fir or cypress, since these woods contain enly minute amounts of tannin. A silver gray stain is prepared by first dissolving a teaspoonful of pyrogallic acid (the photographer’s pyro, obtainable through dealers in photographic supplies) (Continued on page 105) Removing softened var- nish with a scraper ' Home Workshop | Chemistry Simple Formulas that , teresting style—now yours for only 50 cents a ‘ volume. + Seinen ee a HOME WORKSHOP DEPARTMENT Or POPULAR SCIENCE EVERYBODYS LEGAL ADVISER Clearance Saleg © BlGsooks daw 2 HE biggest book bargain of your life! Act quick and you can have this wonderful | Law Library at a saving of two-thirds of the former price. Think of it—an encyclopedia of commercial law, written in a fascinating, in- Handsome Law Library Reduced From $10.00 The entire range of commercial law is covered in these six splendid, full size volumes. There are chapters on ownership, deeds, landlord and tenant, corporations, insurance, marriage, divorce, bank- ruptcy, domestic relations between employer and employee. Every conceivable phase of commercial law is covered in these six books. 1300 Pages Full of Valuable Legal Advice With these wonderful books in your library you are always prepared for any legal emergency. You are sure of your legal rights. You need never make any costly, embarrassing mistakes. No more fees to lawyers! In a single instance these books can save many, many times the small first cost. At home or in your office they prove valuable friends. Send No Money Just write a letter or postcard—without a penny in advance. The six volumes will be sent for 5 days’ examination. Deposit with postman only $2.98 (plus few cents postage) infull payment. Within 5 days you can return the books and get your money back. But we're sure that once you examine and read these handsome volumes you'll never want to part with them. Write NOW before the edition is gone, NELSON DOUBLEDAY, Inc. Dept. H-2512, Garden City, New York We Teach COMMERCIAL Meyer Both Company, the est Commercial Kn wet atetaens a 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 equally open to men and women. Home study instruction. Get Facts Before You Enroll in Any School Ask the Advertising Manager of the leading news- pers in your city, anywhere in the United States, re tod England or Australia about the Meyer Both Company—let them tell youabout 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 $1., Dept. 35, CHICAGO, ILL. Wote—To Art and Engraving Firms: Secure practi- w clkaaen aie MONTHLY

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ant to tion is iC. York $e HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY ——— Home Workshop Chemistry ‘(Continued from page 104) in a glass of water, and applying with a brush. When dry, a second coat is given by dissolving a teaspoonful of ferrous water. A bluish black stain can be prepared by mixing a half teaspoon of potassium per- manganate, a half teaspoon of potassium bichromate, and a teaspoon of pyrogallic acid together with a quarter of a teaspoon of ferrous sulphate dissolved in a glass of water. The color can be deepened on in- creasing the quantity of pyro. Then the color will approach that of ebony. To prevent the wood from roughening, it is first moistened with water, allowed to dry, and is sandpapered. The water stain will not then raise the grain. All water stains must be left at least 24 hours to dry, during which period the color will de- velop and deep- en. Then the wood may be slightly oiled with a_ very small quantity of linseed oil, and, when this is dry, it can be shellacked or waxed. Turpentine stains are seldom perma- nent; they quickly fade away. In making a shellac varnish stain, it is always best to color the alcohol to the de- sired shade before the lac is added. Many spirit soluble dyes and vegetable coloring matters, such as saffron (yellow), sandal- wood (dark red), madder (reddish brown), tumeric (orange yellow), and ana- line dyes, may be used. The wearing qualities of a varnish de- pend upon the hardness of the resin and the liquid in which it is dissolved. For the best results it should be applied only to smooth, clean surfaces; it should not be put on too thick, as it becomes waxy, and not too thin, as it then shows no gloss. A cheap floor varnish consists of 1 pt. turpentine in which 1 lb. common resin is dissolved by gentle heat. Then 2 qt. of boiled linseed oil are added. An- other varnish, more durable and just as easy to make, consists of 34 Ib. alcohol soluble manila copal, 4 lb. purified shellac, 34 lb. Venetian turpentine, and 1% gal. alcohol. If the Venetian turpentine can- not be obtained, ozonized or oxidized tur- pentine can be used, but under no condi- tion employ the substance usually sold in paint stores as turpentine or spirits of tur- pentine.—ERNEST BADE, Ph.D. Mixing an ebony stain for woodwork - ALTHOUGH wood that has to be stained and finished with shellac, wax, or varnish must always be sandpapered with the grain, it is often much better to finish pine or whitewood that is to be painted by rubbing it with sand- paper diagonally or across the grain. The tearing of any very spongy and soft wood may be prevented by giving the wood a coat of size made by mixing hot water with a small quantity of glue. Do not rub the sized surface too rapidly or the glue sulphate (green vitriol) in another glass of | ‘oto. "Built First to Last” SS will soften and gum up the sandpaper. it WHER IER axuneetl You Double the Fascina- tion of Radio when you build your own set. You find it comparatively easy to equal and usually surpass the best results from your neighbors’ ready made sets. And what a thrill to ’ reach out hundreds of miles across hill, stream and mountain range per- haps and bring in the distant sta- tions in full rich volume. All. this with your own personal set! It’s a triumph you’ll talk about. Coto for Efficiency, for Compactness, for Value plein eda OC OEROO SS 8 New Coto Compact Air Condenser with Vernier Just as rugged and efficient as it looks and only 27% inches square on the panel. Constructed ona metal base for rigidity. Insulated with scientific care. Stator plates are soldered to three posts for rigidity and low losses. Rotor plates sol- dered to shaft. Built right to serve you many years. rs 3505 3 3510 000s Mid. 92 ol Mia. 0 Reliable Dealers Always Recommend Coto Quality Dealers value the trade of those who insist on Coto Quality. If your dealer fails you, send us his name and we will see that you are sup- plied. COTO-COIL CO. 87 Willard Avenue, Providence, R. I. Pacific Coast Branch: 329 Union League Bldg., Los Angeles, Cal. Northwestern Branch: Geo. F. Darling, 705 Plymouth Bldg., Minneapolis, Minn. Southeastern Branch: Cc. P. Athineen Atlanta Trust Co. Bldg., tianta, HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY New Coto Compact Moulded Variometer Size only 34% x1%x3%. In moulded bakelite. Stator is hon- eycomb wound. Range 200 to 600 meters. Base or panel $5 mount. Type 8000....... New Coto Compact Variocoupler Companion piece of the Vari- ometer. econ sata in. — 200 to aay meters. Coto Special Audio Frequency Transformer Turn ratio of 3 tc 1. Coto quality The Original Honeycomb Wound Inductence Units Popular low priced favorites of the amateur experimenter. Allow easy variation of coils to get all wave lengths. Sold mounted or unmounted. Coto Tapped Radio Frequency Tr ‘ormer Efficiently covers. the whole broadcasting range because it is owitsh. Type 5000A.. 7-90

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———————— ee —t ————— . Oe ee! Sma HOME WORKSHOP DEPARTMENT OF PUPULAR SCIENCE MONTHLY ° a Write for a copy today pe PON request, our latest radio catalog will be sent gratis to those interested in constructing their own receiving sets. The outstanding feature of our parts, aside from their excellent electrical characteristics, is the unusua! method of mounting and time saving in wiring. All parts are illustrated and described in detail. EISEMANN MAGNETO CORPORATION WILLIAM N. SHAW, President General Offices and Factory: 40 33d Street, Brooklyn, N. Y. HEN “bedtime stories” and fairy tales are shown on the wall—when the whole family can enjoy snapshots, postcards and the like—you’ll realize what an entertaining Christmas gift is a Bausch & Lomb HOME BALOPTICON Ask your dealer. Booklet on request. Bausch & Lomb Optical Co. Rochester, N. Y. New York Washington Chicago San Francisco London Handle for Lowering Upper Sash of Kitchen Window FoR raising and lowering the upper |. sash of the kitchen windows, I -have installed pivoted sash handles in our home, as shown. In most kitchens the upper sash is fre- : quently lowered to let out the heat, steam, and fumes from the cooking, but it is usually difficult to do this without the aid of a stick, especially if OPERATING ffl! POSITION Hil Ht The dowel-rod handle is pivoted to a small brass bracket on the upper sash there is a sink, table, or other furniture in front of the window. The handle illustrated is made from a 54-in. dowel rod slotted at one end and pivoted to a bracket made from a piece of 13-gage brass. The wood is stained and varnished. The rod is just long enough to push in on the top of the lower sash and it there- fore serves as a lock when the window is closed.—W. T. MARKOWSKI. Old Tire Serves as Trough for a Grindstone [NSTEAD of constructing a drip or the usual trough beneath the 30-in: power grindstone il'ustrated, the owner used an old 40 by 8 in. tire picked from his junk pile. He first cut off the beads with a sharp, heavy knife, forced through the fabric with a hammer. Then he cut the tire in two and rounded off the ends of one of the halves. This half was mounted beneath the stone by nailing it to one of the posts that Not only is the tire a good trough, but it also prevents water from sp shing support the bearing. As an additional support for the tire, a frame of thin strap iron was made as shown. There is about 1 in. clearance between the bottom of the stone and the inside bottom of the tire. This idea works well. The tire extends so high about the grindstone that it serves as a guard. Practically no water is thrown out and lost.—PERRY D. WILSON. fnishi handl enam' HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

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HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Making Toys for Christmas (Continued from page 79) ne . finishing, as the enamel should be of a in oa kind that can stand considerable rough handling and washing. If a first class enamel of the color desired cannot easily be obtained, get a good white or cream enamel, and tint it with artist’s oil color in tubes, which can be obtained in any color. The checkerboard should be laid out in pencil on the tray top or bottom, the latter being better if the table is to be used only occasionally for games. Make it. 12 in. square and color the squares al- ternately red and black with a reliable oil paint. The toy garage is a boy’s toy. It can be used either as an independent play- thing or regarded as an addition to a doll’s house, if the children have one. It is intended as a companion piece to the doll’s house described in the Home Work- shop a year ago, and detailed in Home Workshop Blueprint No. 14. 20 in. long, and 18 in. high. The sides are 1214 by 19% in. wallboard, and the front and back 18 by 18 in. The corner posts are 114 by 1 by 12% in.; there are 14 rafters 34 by 34 by 10% in. and a crown % by 1% by 23 in. The front doors are two pieces of wallboard 3 by 10 in., and the side door is 34 by 6 in. Small strips of 14-in. stock form the trim for the garage and doors. How to Finish the Garage The garage should be neatly painted and the trim picked out in appropriate harmonizing or contrasting colors. To furnish the garage with a toy auto, for successful results in radio receiving. Celoron is recoguized by radio ex- perts as the best material for insula- tion purposes. Its high dielectric —— makes it the ideal panel ma- terial. Used by leading manufacturers Many of the leading manufacturers of radio equipment use Celoron in making their standard parts. It is ap- proved by the U. S. Navy Depart- ment Bureau of Engineering and the U. S. Signal Corps. Celoron Radio Panels come ready- cut in eight standard sizes, selected to meet the needs of the set-builder. Each panel is neatly wrapped in glassine paper to protect the handsome surface. The size you want— the insulation you need bee don’t need to wait while your panel is cut to order when you get ready to build your radio set. Just go to your dealer and ask for a Celoron Radio Panel. He will give you, with- Celoron panels are readily worked with ordinary tools at home. They are easy to machine, saw, drill, and tap. Ask a radio dealer for one of the fol- lowing standard sizes: x . out a moment’s delay, the exact size 1—6x 7x4 5—7x18x 3/16 Wood strips and wallboard are used in you want. And—what is more impor- 2—7x 9x4 6—7x21x3/16 building the garage. It is 18 in. wide, tant—you get the proper insulation 3—7x12x% %T—7x24x3/16 4—7x14x3/16 8—12x 18x 3/16 We also furnish Celoron in full sized sheets and in tubes, and can cut panels in special sizes when desired. If your dealer hasn’t yet stocked Celoron panels, ask him to order for you, or write direct to us, indicating by num- ber the size you want. Send for free booklet “Tuning In On a New World” is the title of a booklet we have prepared especially for the radio fan. It con- tains a list of the leading broadcasting stations in the United States and Can- ada, an explanation of symbols used in radio diagrams, and several popular radio hook-ups. This booklet will be sent without charge, on request. To radio dealers: Write for special dealer price list showing standard assortments Diamond State Fibre Company use one of the larger and better com- mercial toy cars or carve a body from soft wood and fit it with four wheels and a “‘spare.” BRIDGEPORT (near Philadelphia) PENNSYLVANIA The little wheelbarrow is a toy for the ‘BRANCH FACTORIES AND WAREHOUSES smaller children, very easy to make when BOSTON CHICAGO SAN FRANCISCO the pattern for the sides is laid out. Painted up realistically, it makes a pretty toy. At the same time it has all the advantages of a regular wheelbarrow from the standpoint of the small boy, who likes nothing better than to cart his possessions around from place to place. The sides are cut with a compass or keyhole saw (or a fret-, band-, or jigsaw, if available) from pieces 34 by 10 or 12 by 3034 in. The bottom is % by 934 by : 121% in.; the headboard % by 6% by 4 81% in.; and the tailboard 34 by 2% by * Offices in Principal Cities In Canada: Diamond State Fibre Company of Canada, Limited, 245 Carlaw Avenue, Toronto CELORON STANDARD RADIO PANEL : 12in. The axle is 14% by 1% by 9% in. i and should be of hard wood. ‘The wheels 60% ofMarket Price ; are % in. thick and 8 in. in diameter. F ¥ Two iron rods about 5/16 in. in diameter dreds re) f Dia monds. lth) i and 10 in. long, with nuts, hold the head oe " together, and one rod 1414 in. long, the Paes tail. Full working details and complete lists of materials for all three toys are con- tained in POPULAR SCIENCE MONTHLY’S Blueprint No. 29. This can be obtained from the Blueprint Service Department, POPULAR SCIENCE MONTHLY, 225 West | defectiveinthenatural ear drums. 39th Street, New York, for 25 cents. A | wheretheyare vt fe. Soft, s complete list of blueprints. previously Ne aay for cnt 168 page FREE book on issued is printed on another page. HOME WORKSHoOp DEPADTASEAIM A. ..

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snc eA ETE 108 HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Your yy Xmas Gifts From | Sweets Deluxe it and pay only 1/5th of the price. 10 MONTHS NEXT YEAR TO PAY THE BALANCE. a Working Drawings for Useful and Novel Christmas Gifts peepee a large variety of designs for useful Christmas gifts in this month’s Home Workshop, you will find some unusually attractive pieces of furniture, toys, and other gifts listed below among POPULAR SCIENCE MONTHLY blueprints. Note particularly the Pullman play table (No. 28) and the toy train, horse, and house (No. 14); the kitchen cabinet work table (No. 27) and the kitchen cabinet (No. 5); the gateleg table (No. 24), the Colonial writing desk (No. 21), the sewing table (No. 1), the smoking cabinet (No. 2), and the two-stage radio receiving set (No. 6). Having a good drawing or design to work by is half the battle. It will do more to insure success in your home workshop than any other single item. The ten- dency of many amateur mechanics is to start out to build something with little more than a general idea of the design in their mind or at best a very rough sketch. As a result, there is no efficiency or method in the construction, time is wasted in checking up details that should have been foreseen at the very beginning, and the builder’s skill and patience are tried. All this can be avoided by having a fully detailed plan in the beginning and a list of materials. For any project other than the most elementary, the home worker will find it is best to make a careful drawing and list of materials, or to make use of blueprints such as those in the Home Workshop series. Complete List of Blueprints a one of the blueprints listed below can be obtained from POPULAR SCIENCE MONTHLY for 25 cents. The Editor will be glad to 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- close...... cents in stamps or coin: No. Title Price KR } "Se eee 25c 2. Smoking Cabinet..... ....... ic 3. Book Trough End Table...... 25c 5. Kitchen Cabinet............. Cc \> 6. V. T. Radio Receiving Set..... 25c 8. Shaving Cabinet............. c B Feed — Gate and Seats..... 25c wing 5c 11. Bench and Tilt-Top Table..... 25c 12. Electric Washing Machine..... 25c 13. Tea Wagon =. aaa 25c 14. Toy Train, Horse, and House. .25c 15. Home Workshop Bench...... 25c 16. Inlaid Radio Cabinet......... 25c 17. Cedar and Mahogany Chest... 25c 18. Telephone Table and Stool... .. 25c onooooooooooOooOoo0oOo0o000000000 John Davey needs young men John Davey’s organization, The Davey Tree Expert Co., Inc., has a limited number of openings for ambitious young men be- tween 20 and 30 years of age, single men preferred. The opportunity is unusual, of- fering good pay at the start, permanent employment in the Davey organization, 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 w:th finefellows. Only élean, 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, Make Your Own RADIO. Receiving Set Use a blueprint of this two-stage regenera- tive receiving set with two stages of ampli- fication, which, under favorable conditions, if . long high aerial is used, will receive 500 miles. The blueprint is easy to understand and contains working drawings, instructions, and bill of materials. Price 25 cents Radio Map of the United States With Dictionary of Broadcasting, Govern- ment and Commercial Stations, Call Letters, Wave Lengths, etc. Price 35 cents Popular Science Monthly 225 West 39th Street New York City 'CE.. : SPECIAL XMAS SERVICE 20. Flat Top Deak... -2..-20.28e nee ee ee ne oe 21. Colonial Writing Desk... ..... 25c é . Guarantee Value 22. Girl’s Cabinet and Desk 25c ee eae Mamend. A: trees: 23. Pergola Garage..............25¢ cobeecad ietly S peeaning nig Swe aaa 26 Gatelon Tale... 5... ccs coves 25¢ FA gape Aer a Sweet Di 25. Sailing Outfit for Canoe....... 25¢ Xmao ies Ever 3,000 ap- 26. Baby’s Crib and Play Pen..... 25c erything;; on 27. Kitchen Cabinet Work Table... 25c es is credit | ; for it 28. Pullman Play Table.......... 25c UM ae . A OE 29. Toy Tea Cart, Garage, etc. ....25c THE HOUSE OF QUALITY itnitie ae! | | Name........... ican’ print ° ‘SWEET act ee a as 1650-1660 BROADWAY, NEW YORK City and State a cis pth Sila wiih: edo hoa hsb enee ® ad TT ponents ee ete Pn a al ne i a, ee ee ee | |=

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avey nber men , of- nent tion, pro- apid, , Of= ation une oply. ie hio, J & era= npli- ons, and and ern- ers, Sasi te Rigas Sepiigten TO ORL: a Using Steam from House -Boiler to Heat Water HEN a steam-heating plant is used to heat water for the house water system, the usual practice is to place a coil of pipes at one side in the combustion chamber. This is objectionable because in small ‘firepots one side of the water jacket is made less efficient and the coil itself is often in the way when the fire is being stoked. The heating device. illustrated was made to avoid these difficulties, and it gives a very quick and hot flow of water. It is made from ordinary pipe, pipe fittings, and copper tubes. The ends of the large pipe are closed and suffi- cient tubes are placed in it, as shown, to give WII. _ wn i SSSSSSS SSS COPPER HOT-7 PIPE: A-} COLD WATER -~ WATER JACKET r“ CONNECTION bette “DRAIN Heating device (above) and general arrange- ment the water heating plant (below) the same area as the area of the outlet pipe. The space around these tubes is connected with the water jacket of the boiler by a short pipe, as indicated. Therefore water at very nearly steam temperature constantly surrounds the copper tubes. Cold water enters the tubes from the bottom and in passing up through them becomes hot. This heater is connected in the usual way with the storage tank, except that the pipe leading into the tank just above the center is an improvement over the regular method.—PauL H. ByYEr. Capping Tool Handles WOODEN tool handle can be fitted easily with a leather cap. Cut off the top squarely to form an even bearing for the leather and then cut a piece of sole leather to suit. Glue this to the top of the handle and fasten with half a dozen shoemaker’s tacks. The end of the wood can’t come through a handle of this sort, and if carefully made, it will last for years.—B. Y. HOME WORKSHOP DEPARTMENT OF POPULAR: SCIENCE MONTHLY 109 & Charges Radio and Auto Batteries at Home Over Night = For a Nickel! For a friend who owns a radio set or automobile, what could be more appropriate than a gift which would eliminate the inconvenience and expense of taking his battery to a service sta ev time it requires rechar The _ se aetton occa esiaa aaa oo. It charges SOLO. SM oon SE tc storage battery in the simplest, quickest and most * Giolent Pannen nop = sible. Connects to an lamp socket—operates silently—requires no watching. Fully automatic in operation—absolu safe. HOMCHARGER’S TEN Potts OF SUPERIORITY 1. Simple—Only one moving and wearing part, 6. Fool-Proof—Can be operated by anyone. ae after thousands of hours use for Attach to lamp socket and connect battery $1.00. Will last a lifetime. either way, Ks will always panes. grade Efficient—Uses less than one-half the current ammeter eliminates guess wor % of any bulb or liquid type rectifier. Will charge 7. Safe—N guy! ofshock orfire. Tested and apy tadio or automobile battery for a nickel. pect wg Gives R ene re val aoe 3. Qutte—Se8 high charging rate of 7 amperes Mey Be minates long waiting fot battery to become overheat or injure bettery. charged. Will charge any “A” or “B™ battery 8. Beautiful—Mahogany and Gold Finish. t, or three ti fast 2-ampere 9. Unqualifiedly Guaranteed. rot gata atari | ae 10. Populasty Priced—Retails at $18.50 com- ete ($25. .00 Canada).. No extras to buy. id nS all dealers. FREE BROADCASTING LIST. Ask; dealer or write direct for end pow ym ml List of Broadcast Stations, tinuous operation—prevent sticking and stop- and Cir Describing the Gold Hom- er. ping. DEALERS! JOBBERS! GOLD SEAL HOMCHARGERS in their attractive ——e oF weg, en ane ying to be “*best sellers’’ = the votes big hag i ve eae for our elaborate merchan then prepare to get your share of this business’’. machine. 4. Clean—No expensive bulbs to break or acids to spill or replace. No acid fumes. Charges without muss, fuss or bother. 5. Dependable—Tungsten contacts insure con- charger Xmas Insist on the GOLD SEAL ACCEPT NOSUBSTITUTE. Like all good products, the HOM- Sas has been widely imitated. No other er is just as INSI on seeing our registered trade-mark, the 5 SAL” on nameplate and carton before purchasing. he AutomaticElectrical DevicesCo., 131 West Third St./Cincinnati,0. co Largest Manufacturers of Vibrating Rectifiers in the World Cleary; Silas || Binge Bistieeda hen boptos o ace or body, Barbers Itch, Enlarged Pore and Oily. or Shing Skin $1000 Cash says reset sears em E.S. GIVENS, 153 Chemical Bidg., Kansas ae. ee eectiInD NEPARTMENT OF POPULAR SCIENCE MONTHLY iil

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“I’m making real money now” EE that coupon? Remember the day you urged me to send it to Scran- ton? lt was the best thing I ever did. “Mr. Carter called me in to-day. Said he’d been watching my work for some time—ever since he learned I was study- ing with the International Correspon- dence Schools. “Then he asked me if I thought I could take over Bill Stevens’ job. I told him I was sure that I could—that I had had that goal in view ever since I started my I. C. S. course. “IT start to-morrow, Mary, at an in- crease of $60 a month. It’s wonderful how spare-time study helps a man to get ahead.” Fo thirty-one years, the I. C. S. has been helping men to win promotion, to earn more money, to get ahead in business and in life. You, too, can have the position you want in the work you like best. Yes, you can. All we ask is the chance to prove it. Without cost, without obligation, just | mark and mail this coupen. INTERNATIONAL CORRESPONDENCE $CHOOLS Box 7665-C, Scranten, Penna. Without cost or obligation on my part, please tell a how I can qualify for the position or in the subject before which I have marked an X: BUSINESS TRAINING COURSES Business Management Salesmanship Industrial Management Advertising Personnel — Better Letters rafic Manageme Show Card Lettering Business Law Stenography and Typing Banking and Banking La Business English ccountancy (including C. P. A.) () Civil Service Cost Accounting Railway Mail Clerk Bookkeeping Subjects Private Secretary High School Subjects DO French Dlustrating TECHNICAL AND INDUSTRIAL COURSES Architect Blue Print Reading Contractor and Builder Architectural Draftsman Conerete Builder Structural Engineer Chemistry Pharmacy ——— ork lane Engines Agriculture and Poultry Mathematics Occupation............. Persons residing in Canada should send this coupon to the International Correspondence Schools Canadian, Limited, Montreal, Canada Big Value for 10 Cts. S'Songs, wei rds and music; 25 Pic- tures mtty aes 40 nba ts: to Make Money; Joke Book on ve; i Mabie Book, i Book Letter nes 1 Dream Book and For- tune Teller; 1 Cook Book; 1 Base Ball Book, gives rules for mes; 1 gee Maker Boo! uage of Flowers; 1 Morse Telegraph Alphabet; 12 Chemical Experiments; = Table; Great North Pole Gleme; 1 Conundrums; 3 Puzzles; . 30 Verses for Autograph Albums. All the above by mai! for 10 cts. and 2 cts. postage. ROYAL SALES CO., Desk 130, South Norfolk, Conn. HOW TO CONDUCT A RADIO CLUB Covers parliamentar; apeacedure, indoor and outdoor experiments, 5. le receiving sets, vacuum tube amplifiers and detectors and many other subjects. 225 West jad New York City Craftsman’s Table Lamp Has Art Glass Shade By James Ellis ‘Tas table lamp, because of its sim- plicity of line, displays to unusual ad- vantage an art glass shade. The pedestal and shade frame can be made of mahog- any, gum, or any wood that can easily be worked, and they can be put together with very few tools. If the lumber is bought, a %- in. board about 2 ft. long will make all the parts. The base may be cut from a thicker piece or glued up from thin stock. It is chamfered on the upper edges and has a mor- tise to receive the column and a hole for the lamp cord. The column is made of four pieces glued together, mainly so that the recess for the socket can be worked out with less trouble, but it can be shaped from a solid, glued- up piece. A regular pull socket is used, but the brass outer shell is discarded and the fiber cdver is glued in the socket recess when the column is assembled. A hole for the chain is bored through one of the sides. The wiring is carried through a The lamp is of ma- hogany and red art glass PULL-CHAIN it RECESS. LAMP CORD Side and top views of the lamp and details of the base, pedestal, and arms central hole to the base before the column is glued together. At the top of the column four slots are sawed, one at each corner, to take the arms that support the shade. These arms are made tapered and are set into the column at a slight angle. (Continued on page 111) HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Jazzy Sax Without Practice . No Lessons Sweet Jazzy Tone Anyone can play this imported Jazzy Sax ae Ag right away. No but a knowledge of music ae _ requir no les- strument. sons, ’Play by Glistening, numbers instead polished of notes—play brass with nickel mouth- piece. Looks like a regular ere the same size. if you wish. Al directions and 30 songs freel Be popular at parties, dances, picnics, by notes or ear ] Beautiful, clear, ringing tones and de- lightful har- mony. No need to spend $85 when you can own a Jazzy ‘ ”9 “This is I played t Easy to P lay y ptt ee a, "—V. D. aft Chi o, Ill. I find your Jazzy Sax is very Au} lay.’ gi Lemke, Apple- = — You, too, delighted with your Jazzy Send No Money 30 Free Songs arrive, bey the postman only $5.98 plus a y the songs right away. oan penny. Satisfaction guaranteed or ube the the * eee is limited——so don't t aelay. es --Send This Coupon Today ——o " FERRY & CO., 75 W. Van Buren Street, | Dept. 1785, Chicago, Ill. ! 1 | Please send me at once your Jenny Sas Sax and 30 Free t Songs. On arrival I will deposit $5.9 us postage | a oT a with the postman. If Iam not ah ey the instrument and you will refund my money. id ; talk about to insult intell Sea How to Make and Use a Small Chemical ~Laboratory By RayMonp Francis YATES. The treatise covers all of the essentials of elementary chemistry. The second part of the book is devoted to chemical and electro-chemical _ . experiments. Price, 75cents | Popular Science Monthly | 225 West 39th Street New York ~ .~3 TD me heed a 05 wee Se ~~ fF re ok ah 112 HOME WORKSHOP DEFVADTAALCAIT An names

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tl emical ersallof ' part chemical 75 cents lew York . laid out full size on paper. The main Craftsman’s Table Lamp (Continued from page. 110) Although it seems rather formidable, the shade is really not difficult to make. If a protractor or bevel is not among the tools available, the frame should first be angies are cut at 60 degrees and the joints are made in the fashion of a half lap, the tongues being % in. thick. The cutting is done on the inside, where the glass goes. The outer angles can be planed, but the inside will have to be finished with a chisel. The shade frame is assembled by gluing together two panels and letting them dry before putting on the connecting pieces. LOWER BAN 2 a 7 JOINT LEAVES ME “SQUARE RECESS gf FOR CORNER POSTS How the pieces for the shade frame are cut out and put together If the lengths have been laid off accu- rately, and the angles cut carefully, they should go together without any troubie. They should be clamped and left over- night for the glue to harden. Since all of the bands are made the same length, it is necessary to trim off the ends of the bands glued first, so that the re- maining bands will go on properly. A file is a most useful tool for the delicate fitting and lapping, as the depth of the laps is only \% in. A place on the bench is cleared off for the final assembly, so that the corners can be tried with a square and thoroughly checked for trueness before the joints are clamped or tied together. At each corner of the shade a small piece of wood is glued to take a small wood screw passing up through the end of each arm. The lamp should be stained and finished as desired before the glass is set. The glass is bought cut to the exact sizes and is put inside the shade with small nails, wood screws, glazier’s points, putty, or sealing wax. HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Special Offer ‘sa children’s ing and thing on small month- ly payments, no risk. We stand beck of this Com; =m prices in ~~ 6 stores — coupon no -00. Don’ be too late for this Offer. Send the NO Elmer Richards Co. Dept. 1789 W. 35th St., Chicago, Ill. well satisfied men \ Heavy Sweater . Send only $1.00 withthe coupon for thisAll-Wool —heavy, jum- bo sweater. Money back instantly if you ask for it. Order NOW! Hea Pure Wool This le abergue pelea. | Men Tes we hd wool. Heavy rope stitch. Largo ioned shawi collar. Twolarze fines . Close knitted wrist- Jets. Ivory buttons to mat Sg Sa fall ter Liat Fer by the credit, do. Ei g you need in clothing or and you paz sa small monthly sums, Open a account with us. No charge for credit. One price y dependable qualities. SSS SRSRSRECRER ESE S SERRE eee esses Elmer Richards Co. Dept. 1789 West 35th Street, Chicago, Ill. I enclose $1.00. Send ~_ * Wool Sweater No. F-12. j-oeeneee= Color. * a I pees setietes when 5 coccinn Mie swentes 5 can re- urn it an my paymen rr Otherwise, I will fe ised terms, $1.00 wi J will Pay, ate $1. coupon, $1 06 The Radio Guide Will Tell You— What radio equipment © you will n How you assemble your receiving set How to adjust the set for Signals What radio stations you can hear How to make a crystal detector receiving set How to make a vacuum tube detector set Important tricks and trouble spots in radio Glossary of principal radio terms What you can hear with a radio set How wireless speech is possible A picture story of how radio works _ The Standard RADIO GUIDE May Save You %5% to 50% A every question of the radio beginner or the man who wants to know more about radio before he begins. Every difficult point is made doubly clear by photographs and diagrams. Price, post paid .. . . . 50 cents POPULAR SCIENCE MONTHLY 225 West 39th Street New York City HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

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112 HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Use Atkins “‘Non-Breakable”’ Hack Saw Do Your Work Faster — Easier RY an Atkins Non- Breakable Blade in your hack saw frame. It will saw the toughest metal faster and easier than ordinary blades, hold its cutting edge longer, and will not break. There’s a reason. These blades are made of selected steel, and are hardened and tempered by an exclusive gas-and-oil process, which gives a hard, keen cutting edge and a tough, flexible body. You can eliminate dosses of time and money due to breakage of brittle blades by using Atkins Non-Breakable Hack Saw Blades. Prove it for yourself. Send ten cents and tell us what metal you want to cut, and we’ll send you a sample blade. Saws for Every Use When you need a_hand saw, citcular saw, band saw, pruning saw, metal cut- ting machine, or any saw for cutting wood or metal—there’s an Atkins product that will save time, money and labor. Write for free booklets on the saws you need. On Saws This book is full of help- saw user and buyer. It shows the right saw for every purpose and contains suggestions that will save you time, energy and money. Write us for your copy, NOW. E. C. ATKINS & CO., Inc. Dept. D-20, INDIANAPOLIS, IND. Makers of Silver Steel Saws and Tools aaa HOME WORKSHOP DEPARTMENT OF POP ful shop hints, and tables.” Worth dollars !to every ~ Old Electric Lamp Makes Novel ““Crystal’’ Gazing Globe CSB ¥eraL gazing globes, sometimes used by seers and mind readers, cost from $5 for the cheapest glass to $500 for the larger, highly polished crystal ones. An excellent substitute, which can be made in the home workshop almost without cost, will give just as much amusement as an expensive globe and can be easily ‘‘doc- tored” to pro- vide mysterious “‘visions.”’ The writer made the “crystal” illus- trated from an old, sphere- shaped, tipless electric light globe. The cop- per shell at the end was re- moved and a tiny hole was filed into that part of the globe formerly covered by the metal. Air was admitted gradually so as to avoid breaking the bulb. A ring was then filed around the socket part, next to the globe, and the sphere shaped part broken off by gently tapping it. Fitted and glued to a turned The “‘crystal’’ globe wood base, the sphere forms an excellent | gazing globe. The diagram shows how a special base was constructed to give entertainment to friends. It was made of a 4-in. length of cardboard mailing tube, covered with black velvet and glued to the wooden base and to the globe. Inside the tube is a small flashlight battery which supplies current to a light when a button switch, concealed under the velvet, is pushed. The light illumines a_ transparent ‘picture and causes it to appear in the PART OF ELECTRIC-~__ LIGHT BULB y vett J _-7*” COVERING OPENING“ PICTURE. SUPPORT ~~=TRANSPARENT WITH OPENING PICTURE CONCEALED "ELECTRIC BULB ae switch =~" a “ CARDBOARD,” _ ORNAMENTAL TUBE ~ BASE. Hidden flashlight causes mvatic F materi- alization to appear in globe globe, as if. a materialization in a séance. The opening beneath the globe for the reflection should be small and hidden as much as possible by the velvet. A picture to suit the “medium’s” purpose is drawn on glass or celluloid or a transparent slide, as for a magic lantern, or is made from a photograph. BEFORE putting a paint brush away wash it thoroughly with kerosene, and while still soaked, wrap it in waxed paper. Use turpentine, gasoline or bezine to wash -it out before using it agaim”” No Money Down While other watch dealers are raising their prices, asking you for larger monthly payments, and mak- | ing payment terms harder for you to meet, we are offering you our new model Santa Fe Special, no advance in price, no money down, easier terms and smaller monthly payments. WE realize the war is over and in order to double our business we MUST give you pre war inducements, better prices, easier terms and smaller payments. Adjusted to Positions Adjusted to Temperature Adjusted to Isochronism Adjusted to the Second Thin Model. All Sizes Without one penny of advance payment let us place in your hands to see, to examine, to inspect, toad- mire, to approve, a real masterpiece in watch crea- tion. A Watch which passes the most rigid inspec- tion and measures up to the exacting requirements of the great Santa Fe Railway System, and other great American trunk lines. Page 12 of our Watch Book is of * Special Interest to You Ask for our Watch Book free—then select the Watch mR, . would like to see, either the fomone Santa Fe Special or the 6 position Bunn Special, an let us explain our easy payment plan and send and watch express prepaid for you to examine. No Money Down. Remember—No money down— easy payments buys a master timepiece—a 21 Jewel guaranteed for a lifetime at about half the price you pay for a similar watch of other makes. No money down—a wonder offer. SANTA FE WATCH COMPANY C.80 Thomas Bidg,, Topeka, Kansas . (Home of the Great Santa Fe Railway) é A Letter, Post Card or this Coupon Will Bring“ My Beautiful Free Watch Book SANTA FE WATCH CO. 80 Thomas Bidg. +» Topeka, Kansas alae send me your new Watch Book with the 4 understanding that this request does not obligate me in any way. re at RI ~ ¥ * sth pe a agence eats etc. Only re reserves | Ss rage roan quality ality PROFESGIONAL Sare- ULAR SCIENCE MONTHLY - In Your Home Our marvelous prac- tical tet My a- . ite Ni PARAMOUNT W MFG. FG. COMPANY , Mass., U.S. eee

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ements d other is of © ect the ;|:shallow enough so that, when placed on Radio Receiving Set Fits Well in Sectional Bookcase cGy radio fan solved the problem of providing a neat and convenient cabinet for his radio receiving set by put- ting it in one compartment of his sectional bookease. A 1-in. thick wooden base- board was stained ebony black, and the composition panel was attached to the base with short brass screws. The set was A convenient place for the radio set. The loud speaker, if used, can be placed on top of the bookcase the bookshelf, the sliding door of the compartment could be shut. Being placed in the third tier, the set is just the right height for comfortable operation. The cavity to the right of the panel is utilized as a storage place for the head phones, and a hook screwed to the end of the bookcase supports wires that run to the batteries. The batteries are placed in a neat box, stained and var- nished to match the bookcase. When adjustments are necessary, the set is pulled out bodily and placed on a table.—J. R. Cheaply Made Bins for Nails, Screws, and Hardware wate home workshops and garages have not a sufficient number of bins or drawers for small parts, such as bolts and nuts. An economical way of CUT-OFF CORNERS IGAL.CANS ‘ 4 t Empty oilcans with a corner cut off make handy containers in the home workshop making containers for this purpose is to cut a corner off empty one-gallon cans, as illustrated. This is easily done with a can HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY stations. Price $5.00 Write for booklet on radio-frequency DUBILI @ DEV The DUBILIER Duratran— Amplification on all wavelengths HE Dubilier Duratran is the su- preme radio-frequency trans- former. It amplifies powerfully and uniformly over all the wave- lengths now used by broadcasting At all good dealers amplification DUBILIER CONDENSER AND RADIO CORP. 48-50 West Fourth Street, New York ER ICES Dubilier Mi- cadon (Fixed Condenser) Dubilier Va- riadon mica variable con- denser. oT Oe CBS BREE ABT $25.00 in PRIZE See top of page 8 in front of book for details Learn AUTO PAINTING ‘THE best paid profession in the indusiy—* ri- ence not necessary. We teach everything A to Z in 8 to 10 weeks. rom More men are needed. Now you can Factories are call for men tart je ati , nce of d your own with no | eomag ens od Send than — opener and tin snips. er eel oune. maak lore. Our special couse press The handle is used as a pull for the bin oh you toc aan seore profession. Personal and also provides a place where a label can poeeer:: ermmeaggin Ail information free. cessful Traffic Men. Special plan to belo pay DETROIT AUTO PAINTING SCHOOL our tuition. Post course F E. be glued. Shelves may be arranged to The pioneer, the largest and best Eta Ses in U.S. A. Weite today for fell formation, oa hold any number of cans.—J. E. 1471 Van Dyke Avenue IT, MICH. Fa ) , Sapent Fate aot HOME WORKSHOP Fr 1 DEMAND INCREASING D $50 to $300 a Week. With the energetic revival of business activ- ities, the demand for men trained to handle“ iC DEPARTMENT OF PQPULAR SCIENCE MONTHLY , »

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HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

Camping Out at Home with a f ‘Fireplace Cooker THOSE who have an innate desire for campfire cooking, I suggest an occasional meal prepared on a tripod over 4 the flames in the fireplace. Try this fora picnic Sunday supper or for that luxurious night when the maid is away. The tripod is nec- essary because modern fireplaces, although quite com- mon, rarely have cranes. It is simply a triangle of iron with 7- or 8-in. sides mounted on ; The iron tripod legs that have a slight outward spread for steadiness. The legs may be 4, 5, 6, or more inches high. You can have the stand made by your local blacksmith. This tripod, which can be placed right over your fire, supports three pans, one on each corner. With a lively blaze to cheer you, you can cook whatever you wish and broil steak over the coals beside.—A.D.P., Hindman, Ky. Shed-Roof Brooder House Serves Double Purpose i el als

The FLORSHEIM SHOE Men who appreciate the finer things of life look upon THe FrorsHem Suos as one of the requi- sites of daily comfort and correct appearance. The Rodney —Style M-131 Most Styles $10 Booklet “‘Styles of the Times” on request THE FLORSHEIM SHOE COMPANY CHICAGO

eg PovEray raisers who are planning to i. build new chicken houses will find a useful suggestion in the accompanying illustration of an up-to-date shed-roof brooder house. It was recently designed and built by the Poultry Husbandry Divi- sion of the Bureau of Animal Industry,

Prices Reduced On All Standard Make TYPEWRIT ERS LowestPricesinYears |. 2 <n Mewihehtpeuyanise Aye Try this beautifal. 14 Mais math pions

Bea sten, liver, ete Easy Terms f2” than rent each at and own @

n potiad after 10 daye trial Solendad tor gifts = Cterietmes, Birthdays, etc. THE BRITMOR CO., Dept. PSM. 286 Fifth Ave., New York City

Now, you can saw 15 or more Fastest sawing: easier cords of wood each day with stftinany weather. 4H-P KER sila abtuap ae. Saw. With uae Shipped quick from nearest to you of @day. Send for SPECIAL OFFER, now. "i2© branch houses at low —, NEW MODEL: 222142 OTTAWA 4 in 1 1: tnformation, Shout the S—BUZZES UP BRANCHES oh Rn ne 7 Saws Woes) 4—DOES BELT WORK lOG SAW ry-to-User Offer! and te 8 FREE 82-Page er

and the interior wit er stove (below)

= The outside of the poul hemi toheess , r ’ United States Department of Agriculture, for experimental use at the Government poultry farm, Beltsville, Md. The house is 10 ft. wide in front and 14 ft. deep. It can be used for laying hens as well as for brooding purposes, so is espe- cially valuable on farms where chicken raising is more or less of a side issue. When used_as a brooder, the chickens are kept near the stove for the first two days of their life-——S. R. WINTERS. pa er Sut. Send your name ra ~ e Get, BiG Facto SS = sega — a

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ith a » desire rest an od over is fora xurious is nec- cause eplaces, te com- have simply of iron r §-in. ted on lave a tward may be an have ksmith. d right , one on (0 cheer rish and Le D.P., Serves ning to l find a panying ned-roof lesigned ry Divi- ndustry, choot » (below) riculture, vernment nt and 14 1g hens as 0 is espe- 2 chicken issue. » chickens . first two ‘ERS. HOME WORKSHOP Simply Made Concrete Strongbox Safeguards Valuables By George A. Luers T= advantage of having a fireproof and, if possible, secret container in the home for deeds, notes, valuable papers, jewelry, and silver plate, can hardly be overestimated. Any one who has been through a fire or suffered a burglary knows the dollars-and-cents value of a good strongbox. The small deposit boxes available at banking places are best of all, of course, but relatively few householders find it convenient to use them for every- day purposes. To make up a serviceable small safe deposit box of concrete is not difficult and it will be fireproof and, if well concealed, Wy | ag CELLAR WALL lpliddha REINFORCING WIRE I gt aie FORM FOR INTERIOR OF BOX Cut-away view of the completed strongbox and the wooden forms practically burglar-proof. A basement wall location is usually best. If the box is built into a wall it cannot very well be removed from the building, and if it is concealed with a screen or shelving, it is not likely to be discovered by any outsider. A 2-ft. square excavation, about 3 ft. deep, is made into one of the walls at the desired location. A box form is con- structed of wood to form the mold for the interior of the box; this is about 15 in. square and 30 in. deep. The cavity itself serves as the outer mold. The concrete mixture should be quite rich in cement, the proportions being about one part cement to two parts sand. In pouring the box, the forward top sec- tion of the form is left off; the concrete is then poured in and tamped, and the final filling is made at a small aperture above the edge of the top of the form after the top piece is put on. To do this properly requires some care and the mixture must be quite liquid, in order to prevent any “‘voids’’ being left in the concrete. In many cases it is easier to dig down through the earth from out- side, if the distance is not great, and fill the back part of the form from above. In fact, various expedients can be adopted in pouring forms of this type. Meshed wire is used about the front of the box to (Turn to page 116) KENYETH SARKNESS What This Book This book will teach you elementary and ad- vanced radio—with hardly any effort en your part! Kenneth Harkness wrote this book with you in mind. He realized you have absolutely no use for radio books full of complex equations and in- volved statements. At the same time he knew you don’t want to read a book which is too simple and elementary—which doesn't teach the things you want to know. So Mr.. Harkness wrote his new k in your language—the language you use every day; the language you understand. His fills an open gap in radio literature. He ex- plains advanced radio—hitherto understood by mathematicians only—yet he explains it in simple easily understood English. He sits right down with you and explains in easy-to-grasp language the big important things in radio you always thought were too complicated to understand. In the first part of his book the author leads you step by step from the elementary laws of electricity to the advanced principles of radio reception. His arguments are so skillfully worded; his explanations are so simple and understandable that you will quickly and easily learn how modern radio receivers operate. In the second part of his book he will tell you how to build receivers—with all the details of con- struction. He doesn’t leave anything to your imagination. He tells you exactly how yoy can build your choice of 5 different types of modern radio receivers. With 175 diagrams, drawings and action photo- graphs each consecutive step in the “f A construction of these receivers is un- Oo folded for you with the graphic clears ness of a talking moving picture. The very first day you start reading SEND NO MONEY JUST MAIL THIS wee ccnencosesocoucocewesgUreNecces this book you will feel yourself growing in knowledge. Everything is so de- lightfully clear; each subject is taken THE RADIO GUILD, Inc. sete 34th St., New York, N. Y. Please sei lineation,” laining the theory po Finan F that if I am not absolutely satisfied I can OP rg mag Ape new Kenneth Harkness book ‘‘Radio Frequency Am- A. gh ey of radio reception in simple language. When” the boo! ives I will depoak $1.25 (plus a few cents postage) with the postman. It is may return the book within five days after receipt and you will refund my money without question. NePianc we ctbehs teeigeds sds nticnns eendeawnee Pe Aare. ood Sa cn ane dee eG omcaty (Orders from Canada and other countries outside of the U.S. are payable $1.50 cash with order.) DEPARTMENT OF PQPULAR SCIENCE MONTHLY 115 This Amazing Book MakesRadioEasy It _it explains to vee in easy-to- anguage the theory of pase reception from A to Z. It tells you everything you want to ow about radio—answers all your questions. It shows you how you can easily build at very low cost a new easy-to-operate one tube radio receiver which runs a Joud- speaker! It also shows you how to build four other types of mod- ern luxurious radio receivers. If you already have a radio re- ceiver this book will tell you how to add a Radio Frequency Ampli- fier and thereby make your set receive stations thousands of miles away. This astonishing book actually tells you how you can banish in- terference from your receiver. All the latest developments of the radio laboratories are dis- closed in this remarkable book written by Kenneth Harkness, ae Engineer of the Radio Guild. Examine this amazing new k and judge for yourself. Mail the coupon below for your copy today. ‘Means To YOU up so smoothly and simply that you will clean forget you are actually learning advanced radio—actually learning all about the operation and construction of the latest types of radio receivers. Special 5-Day Examination Offer You've always wanted a real live, practical radio book like this. You can have it for the asking —without paying a cent in advance. In fact, we are so confident that you will be delighted with this book that we will send it to you for 5-days’ examination and let you judge for yourself! Just fill in and mail the coupon below. Don’t send any money—pay nothing until the book is actually in your hands. When the postman arrives deposit with him the full price of the book—only $1.25 plus a few cents post- age. Examine the book for 5 on Read it from beginning to end. See for yourself how it expands your knowledge of radio, Learn all about the re- markable receivers Mr. Harkness describes. If you are not absolutely satisfied, if you do not feel that the book is all that we claim and more—send it back and we will promptly refund your money. That’s fair enough, isn’t it? You take no risk—you've nothing to lose and everything to gain so mail the coupon today and get your copy by return. Don’t delay—you may forget or misplace this advertise- ment and thereby miss this great opportunity. Do it now while you're thinking about it. P. 3.—12-23 HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 117

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ee as “ - - - - - — — _ . siete . . —_ “a ~ DA ER AOE Nt ea SY Se sete — ‘ é 116 HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Price Cut 4 On World’s Greatest Reference Books Latest Edition Let experts work for you—in these books you will find the most remarkable collection of practical job experience and vital knowledge that was ever assembled in book form. More than 200 of the great- est engineers, lawyers, business men, and practical experts—all of them men who have gone through the mill—give you in these books a lifetime of val- uable inside information on the line of work in which you want to get ahead. Make their knowledge and experience your own. Let them show you all the newest methods—the best ways of doing things. This very minute you may be up against some tough problem—if you had these books you would solve it instantly. Send the coupon for A Week’s Free Trial Just fill out the coupon and we will immediately send you any one of these libraries express collect. Read the books over carefully. Test them out thor- oughly for seven days. If you do not want them, send them back at our expense. If you decide that they will do for you what they have done for 280,000 other men to whom they brought more money and success, pay $2.80 within one week and $3.00a month thereafter ‘until the special price is paid. This amounts to only 10c a day. Mail the coupon NOW if you want a bigger, better job and bigger pay. Free Consulting Membership A resident staff of from 15 to 20 practical experts is waiting to solve for you any difficulty that you may have. letter or a wire to Ameri- can Technical Society will bring you an immediate an- q swer and the solution to Your Choice problems, This advise: ory staff of practical men 75c a Week plus your working and na erence library will enable ‘ you to handle successfully Carpentry and any jobin your line. These 1 the latest 5 vols. Contracting —was. men know al $37.50 now____._-- 19.80 methods and the Bewest = ‘2 vols. American Law best ways of doi: ag th and Practice (includi Let this pay-rais: =| sulting staff be YO LENT PARTNER, This free consulting membership offer is good for a limited $45.00 a. pore and can be vols. Civil ob eel ring withdrawn without was $67.50 now--_ _.34.8 notice, vols Business Manage- Send No Money ‘ment—was $52.50 now “42 RR RE aE 29. Here is your opportunity vols. Steam and Gas if you want to earn more Eagincerins — was money. Remember we are 24.80 taking all the chance—you vols. Sanitation, Heating pay nothing until you are and Ventilating — was thoroughly convinced that 00 now-.-.---- 14.80 these books will help you vols. Fire Prevention to greatly increase your and Insurance—was y. Isn't this about the $30.00 now---...--- 14.80 fairest proposition that was vols. Modern Machine ever made you? $45.00now..--.-.-21.80 American Technical .00 4.80 Society 4 yols «Drawing — ae Dept. X-920, Chicago, Ill. © A.TS. 1923 SE Se eee eae ee ee ean & AMERICAN * c Saomisames SOCIETY, Dept. X-920, C at lease send me a set of for seven days’ FREE EXAMINATION, shipping charges collect. I will examine these ks thoroughly, and if satisfied will send $2.80 within seven Gasp and $3. month until I have paid the special price of $-.--.- If I decide not to keep the books, I will return them within one week at your expense. It is understood that if I keep the books | am entitled to a FREE Consulting Membership in the American Technical Society. con- R SI- ard ‘oO $97.50 now_-_-__.-- 49.80 vols. Applied Electricity —was .00 now - .29. vols. Auto Engineeri —was ‘ase aro 6 A O a ee i ee ad vaccckans. bankas ot employer as reference.) Simply Made Concrete Strongbox (Continued from page 115) prevent the concrete from cracking and breaking out. A wooden form is made for the door, as indicated, and meshed wire is used as re- inforcement. The hinges and hasp are set in place as the concrete is poured, so that they are cast integrally. These parts are wrought-iron fixtures of heavy construc- tion, such as are used for barn doors. The pin parts of the hinges, which enter a wall section, are wrapped with wire and the ends are left protruding into the form, so as to make a solid bond into the con- crete. After the concrete has hardened or set for a period of two weeks, the interior and door should be finished with paint. Lin- seed oil is used for the first coat, followed by one or more coats of any good paint and a final coat of white enamel. A good strong padlock serves as the lock. If the casing and door have been made carefully, with the concrete thor- oughly mixed and reinforced with wire, and the hinges and hasp set to match up evenly, the box will prove a tight, safe, and commodious receptacle for the small valuables that are not infrequently a total loss through fire or burglary. Leather Flap Protects Padlock from Snow and Ice ALTHOUGH the better grades of pad- locks are designed to withstand ex- posure and abuse, they will last longer and be easier to handle if protected with leather or rubber flaps, as shown. Even in the most severe weather, these pro- tectors prevent the padlocks and hasps from becoming frozen and caked with ice and-snow.—F. J. A. To Clean Household Brushes RISTLE brushes should be washed with lukewarm water and a little ammonia, although borax or soda can be used in place of ammonia. Cleanse the bristle part thoroughly, shake out, and let the brush dry in the sunshine. Dipping the bristles in a strong solu- tion of alum will make them stiffer —R.C. rating cee —And comprehensive, too. The new Valley Battery Charger, Type ABC, charges all Radio storage batteries— 2-volt peanut tube batteries, 6-volt A Batteries, and 1 to4 B Batteries. Also charges 12-volt batteries, Plugs into regular electric light sock- et. Uses a negligible amount of cur- rent—a dime’s worth for an average charge. Unfortunately, production is limit- ed. Don’t miss out, and don’t buy another until you have seen the Valley Type ABC Charger. At all good radio dealers. VALLEY ELECTRIC CO. 3157S. Kingshighway St. Louis, Mo. a glance through the Unbreakable parent Valve Cover amount of air in tires. AiR-GAGE ‘iv Tubes peg bd sg to almost every car owner because th tolif a ete eet oe a ear owners. Our million dollar : - factory 500 more pees Bt ie bow the Paul fan will asa an bi a cubes best ness without Write for Free Today, THE PAUL iL RUBBERCO., Bcat. 54, Salisbury, N.C, ADD $5.00 a DAY to YOUR PROFITS with a TORIT ACETYLENE TORCH No. 13 For radiator repairing, general piieine, light braz- ing, heating, battery repairing, etc. Produces instant hot flame, works rapidly. Furnished with 4 different tips and soldering copper, enabling you to do a wider range of work. TE oe eee Paul Welding & Mfc. Co. 164 W. 3rd St., st. Paul, Mivn. HOME WORKSHOP DEPARTAIENT OF DPOpriraD crorairn4n + sat tis aha se 2 ta

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HOME WORKSHOP DEPARTMENT OF. POPULAR SCIENCE MONTHLY | Adding Humidifiers and Wicks to a Hot-Air Furnace F YOUR furnace is of the old-fashioned hot-air type, it probably has only one small waterpot and that in the bottom of the furnace. This is too low to get very warm and therefore does not supply a sufficient amount of moisture to humidify the air properly. Since dry air at 80 degrees is not as healthy and does not feel as warm as air at 70 degrees, or lower, with the proper amount of moisture, it is important to add additional humidifiers. This can be NEW WATERPOTS ASBESTOS PAPER \ fm Bai if eth il h at wii =F TT y il il 1° mi see ne vw jy Y/// % UM WW ] |! I ' tn Mo i HOT-AIR CIRCULATION OLD WATERPOT WITH WICK ADDED Two water pans are added high up in the furnace jacket, provided with asbestos wicks done without great expense if the furnace man, while overhauling the furnace for the winter, places another waterpot or two close to the top of the furnace jacket. Have him also make asbestos wicks for each waterpot, as shown. If you can do the work yourself, so much the better. The working of these humidifiers is obvious. The’ ééld air is heated and in passing up is deflected around the wicks, absorbing from them a _ considerable amount of moisture. Care will have to be taken to fill the waterpots at least once a day, as in actual operation it was found that these wicks suck up and throw off at least 2 or 3 gallons of water a day.— JoHN H. WAcK, Toledo, Ohio. Bicycle Tire Tread Prevents Oilstone from Slipping T° PREVENT my oilstone from slip- ping on the bench while I am sharpen- ing plane irons and chisels, I have tacked to the bottom of the case strips cut from an old bicycle tire. Rubber from an old auto shoe, a number of small rubber head nails or screws, or almost any form of rubber will serve the same purpose and make it unnecessary to hold the stone in the view, Sian ———|\f +7 DIAMOND saving time.— HAROLD A. oe a, Pa a WAT Cc Ei |S oO , Oe ©? OO Broadway~New York HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

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Give Him His and win his everlasting gratitude by presenting him witha Conn instrument! For a Conn not only enables him to develop his musical talent; it gives him wholesome fun and companionship with fellows of his kind, develops a real spirit of team-work; in a word, builds character. Besides this pleasure and popularity, many boys earn their college expenses and more with their musical ability. His Conn instrument inspires a boy to do his best, because he knows it’s exactly the same as those used by the foremost artists in the world. And the easy playing qualities of the Conn, the beautiful tone, fect scale.and reliable action make practice a pleasure, speeding his progress. With all their exclusive features Conn instru-" ments cost no more. Send now for “FREE BOOK and details of Free Trial, Easy Payment plan on any Conn instrument — cor- net, saxophone, trombone, clarinet, flute, any wind instrument. Conn is the only maker of every instrument used in the band. Mention instrument. Conn Dealers and Agents Everywhere C. G. CONN, Ltd., 1232 Conn Bldg. Elkhart, Ind.

WORLD'S LARGEST MANUFACTURERS OF HIGH GRADE BAND AND ORCHESTRA INSTRUMENTS CULTIVATE YOUR MUSICAL BUMP

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

Butterfly Wing Table Makes Charming Christmas Gift By Stanley W.* Blanchard ‘THis little table is a beautiful piece for any hall or odd corner, especially if placed underneath an antique mirror, with candles at either end, and a vase of flowers or an old-fashioned tray with a candle snuffer in the center. It has such charm and individuality that it will pay, many times over, for the trouble of mak- ing. It is especially suitable for a Christmas gift. A little lower than the average table, it will be found useful beside the comfortable chairs of the living-room for tea or games. The table, when folded, occupies a space only 12 by 30 in. Any good wood will look well in this table, but as its lines are Colonial, a dull or hand rubbed mahogany is, to my mind, best suited. Any of the methods of

- Ng " ee ~~ ell ——— ee This ornamental table measures only 12 by 30 in. when it is folded finishing antique furniture described in the May, 1923, issue of POPULAR SCIENCE MONTHLY may be used with excellent results. The mortise and tenon construction is well within the ability of the average home worker. The only screws used are those holding on the table-top and hinges. The most difficult part, in my estima- tion, is the making of the rule joint forming the hinge between the leaves and the top. This can be made quickly with a combination molding plane, if available. Any one who never before has made this kind of a joint will do well to make an experimental joint first on the edges of two waste boards, and actually mount the hinges. In putting on the hinges, the one big thing to be observed is to have the center line of the hinge coincide exactly with the center line of the quarter-round part of the molding. If this is done and the joint is planed true, it will work smoothly. It is not absolutely necessary to use this joint. The edges may be left square and hung by hinges in the usual way, but the rule joint adds a craftsmanlike finish. The edges of the top of the table and of the wings should be well rounded. The wooden pivot on the bottom of each wing, as well as the top metal pivot, should be lubricated with graphite before being put in place. (Continued on page 119)

Laye Layer Stromberg-Carlson Head Set Coils are wound \ a layer at a time with a wrapping of tough in- 4 sulating material between layers. This high grade construction is revealed by sawing through a section of a coil taken from the— It’s the only Read set construction which will stand up under the high plate voltages now prevalent for loud speaker hook-ups. Therefore, it’s the only head set construction | , which ensures permanent sensitivity. It’s a construction which is an exclusive fea- ture of Stromberg-Carlson Head Sets.

Insu

Stromberg Carlson HEAD SET

Ask Your Dealer j Stromberg-Carlson Telephone Mfg. Co. / ; ROCHESTER, N. Y.

with an ASTRA } Automatic will cost little Home Protection Nearly every man wants a gun in the house—he feels better able to protect m ay © hn are able to = these { nuine ra guns at special prices i because we bought before recent tariff r raises became effective. Really fine guns, beautifully finished, hard hitting. Use standard ammunition. Order direct from U. S. importers. $7 15 25 calibre—7 shot—C. O. Q. Automatic. 8.95 25 calibre—7 shot—Astra Automatic, 0:98 33 <n 10 shot Astra, extra magazine = re—10 sho extra m: ; 6.96 32-20 and 38 cal. swing-out cyl. revolvers. We guarantee every gun against defective work- manahi ; brand new; of Drop Forged Stee! Through- out. fore buying any weapon INSIST on this guarantee. SEND NO MONEY unless you wish. State model d i—pay postman on delivery lesired. lus e. Satisfaction guaranteed or money re- Rinded. rite for new ‘firearms catalogue. 4 CALIFORNIA TRADING CO. Termina! Bidg., Los Angeles, Cal. nh hk Dept. 112,

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Small Butterfly Wing Table (Continued from page 118) The holes in the top stretcher for the metal pivots are bored slightly deeper than the length of the pins to aid in assembling or removing the wings if it is ever necessary to do so. By turning the table upside down the metal pins of the wings will fall to the bottom of the holes,

% ORILL ooo FOR METAL PIVOT amen h yo! e—— 17% = yy THicK

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PHANTOM TOP vIEW

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Top, end, and side views of the table and details of the wings and rule joints thus partly freeing the wings, which may be drawn to one side to clear the top stretcher. Then the wing can be drawn from the bottom socket. If the holes in the wings for the metal pins are counter- sunk, as for .a screw head, it will aid materially in replacing the pins when the table is right side. up.

Time-Saving Scale for Making Half-Size Drawings N° infrequently a home worker or mechanic finds it necessary to make a half-size drawing when he has not a special scale graduated for that purpose. An ordinary scale graduated in sixteenths and thirty-seconds can be converted into a special scale by gluing or tack- ing to it a strip of heavy white paper, on which the figure 1 is marked at a point matching up with the 4-in. graduation; figure 2 at the 1-in. gradua- tion, and so on. The time taken to convert the scale will be more than made up in the actual draft- ing, as it eliminates mental divisions otherwise necessary and lessens the chance of error.—C. M. W.

STRIP OF PAPER How the paper strip is marked

Tapping a Hole Oversize’ ECENTLY I found it nec- essary to tap a hole out to 25/32 in. and not hav- ing a tap this size, I first tapped the hole with a 34-16 thread tap. Then I placed a piece of 1/32-in. soft tin on the top edge and ran the tap in again. This did the work well.—R. T.

A useful “‘kink’’ for rough work

( INGERS, bands, orchestras, speakers, organists, humor- ists—an unlimited host of per- formers are yours to command when you own a Tuska Radio. A simple adjustment of dials, and you can choose between them. Dozens of programs are in the air. Your Tuska will bring in whichever entertainer pleases you best and shut out all others. Tuska owners are not obliged to tinker incessantly and add devices to correct construction | 5 Grows : Each set in this increased pro- faults.. Their pleasure is un-, marred by troubles. Every Tuska set is finished with ex- acting care by painstaking New England workmen—the best that live. Then it is examined and tested on distant signals by

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 119

RaDIO Tuska Popular No. 225 3-bulb Regenerative Receiving Set. Piano finish mahogany cabinet. Amplifier switch. Concealed bind- ing posts, Armstrong circuit, li- censed under Patent No. 1,113,149. Price $75, without bulbs, batteries or loud speaker. Ask for special circular No. 19-D, describing this set. .

our entertainers are ready inspectors who are keenly critical, Both manufacturing and testing are under the per- sonal direction of C. D. Tuska, a pioneer radio engineer. For a dozen years before general radio broadcasting be- gan, Tuska-made instruments were famous among radio ex- perimenters for skillful design, superb workmanship and high efficiency. In the past two years, the demand for Tuska Radio has grown enormously. duction of to-day is as per- fectly built as the finest Tuska instrument ever made—and yet, the prices are remarkably moderate for high-grade radio receivers. Ask any first-class radio store to show you one of the models of Tuska Radio, priced $35 upward. THE C. D. TUSKA CO., Hartford, Conn. Ogden, Utah, receives Troy, N. Y. “In one evening, using Tuska 225 with one amplifier only, I received 19 stations, including San Francisco; Calgary, Alberta; and Troy, N. Y. Conditions were not abnormal, and the same stations were received again last night. W. D. GARNER.”

Picks up Davenport the first time he tunes. “I never had my hands on a set until my Tuska came Saturday. First evening, I tuned in Pittsburgh, New York, Richmond, Ind., and Davene- port, Iowa, It certainly was great. WM. PARSONS, Salisbury, Conn.”

\. Music Lessons is At Home With Celebrated Teachers oeaay. ot anew method, Long established School now

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Chicago, Illinois | Dept. B

E19-112 PAGES CATALOG "ss One of the largest ou stocks in the world. 40 diagrams of latest Hookups. DEALERS ALL OVER THE U.S. Making big rrofits handling-our supplies, 24-hour service. Goods shipped: same day order received.

. ’ 107 E. 13th St, Kansas City, Me.

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

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HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 433 Have plenty of clean heat. Save 20 to 50°/o on your coal bills. Equip your heating plant with a CROWN FUEL SAVER and learn what winter comfort means. Over 10,000 satisfied users of the CROWN are getting more heat, steadier heat and cleaner heat. They are cut- ting down their coal bills 1/5 to 1/2; eliminating smoke and deadly gases; and re- ducing the number of times they must fire the furnace. care or attention. Never gets of natural draft, the hot oxygen to burn the rich gases that rise the chimney as “smoke.” this waste into intense heat and The CROWN does its work without any The CROWN fits the feed door of any heating FREE book let plant (see illustration) and provides, bed. These gases are ordinarily wasted going up The CROWN turns perfect combustion. The CROWN may be easily installed without putting out your furnace fire, P WARM (his winter out of order. by means 30 cents.’ (air) necessary from the fuel mate size of grate. Distributors Wanted. assures almost Begin your ‘‘coal and money saving’’ NOW. Write for details and price of CROWN and for ‘*Making the coal bill look like As the CROWN comes in 4 sizes give name and make of furnace and approxi- High-grade men can build profitable businesses in their com- munity. Write for interesting proposition. CROWN FUEL SAVER CO., 12N. 10th St., Richmond, Ind. BDO eral TERLIN 5210 » NEW LOW PRICES—SAVE 1/3 5 ay, Slats how buy cn cradit atlowsrptnes DIAMOND Fm ie be | ARK ROW WORL Bates stig FORK). =>. wed BOYS! used with above for Bird R FAILS. which A p= ves full instructions on riting [Invisible Ink], 12 Money of sigh NE ROY. NOV. 43 VENTRILO, a little instrument, fits in a. Shing nea “a 10 BIG te, sey Pod MAGIC all for (0 LARGEST ie: obeel Mail fe ein =. See. BOYS! e can use it. dise © 83 i PAG GE “BOOK Ventril OF on 2 3 Desk 1951Y Magee Bidg., OTTAWA MANUFACTURING co.. 1951Y King St., Ottawa, Kansas. Pittsburgh, Pa. le and objects miles a Telescope ag new lh ~~ +y' ‘4 tniles away.”’—Mrs. ¥ 3-Ft. Telescope , on land or sea, out over 3 feet Useful and Entertaining (in Five Sections) close. Wonder "3 mp, eral hy = ee "Saw ProvineBtown as clear as if in front of me."’ “gPrce OFFER! While they eS st HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Phonograph Operates Novel Christmas Tree Flasher By R. H. Kasper IN LIGHTING a Christmas tree, the chief aim is to produce a novel and pretty effect. This is usually done by arranging various colored lights and, if possible, by providing an intermittent flashing arrangement. The flashing can be taken care of quite easily by the simple phonograph-driven flasher jllustrated. It gives a greater number of combinations than the ordinary flasher and at the same time requires no electric motor. The metal turntable of the phonograph is removed and replaced with a wooden disk carrying a number of brass screws that project on both sides. As this disk revolves, the screws form contacts with WIRES TO LIGHTS WOODEN DISK CONTACT POINTS teow eee FIBER BUSHING CONTACT POINTS BRASS SPRING CONTACTS With only four strings of lights, this ingeni- ous flasher gives 15 different combinations brass springs arranged on both sides in a holder, as shown. The number of brass springs or contacts carried on the upper and lower boards of the holder depends on the number of lights used. One contact is required for each string of lights. Four strings will be sufficient for the average home tree. It will be seen that each screw that passes through the spring holders is insu- lated by two fiber washers and a fiber or rubber bushing. This may not be abso- lutely necessary but is done as a matter of precaution. Each contact on the upper contact board is separate and carries a wire to a string of lights. On the hower contact board the screws are connected with each other by a wire. This makes it unneces- sary to provide a wire for each contact on the lower board. The method of fastening the contact boards is merely a suggestion, as much depends on the type of talking machine used. As it would not be desirable to (Continued on page 121) screw them in place, they may be held in’ -s ~~ = © © 5 bee

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raph oden crews disk with rmi- ons ina acts is of r of | for ll be that nsu- r or bso- or of tact toa tact 2ach Ces t on tact uch hine » to d in’ Ss ath sae ee

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

Phonograph Operates Flasher (Continued from page 120) position by weights, by placing them in- side the cabiret and using soft wedges, or in any way that suggests itself. When a screw on the disk passes be- tween an upper and lower spring contact, the electrical circuit is completed and the lights light until the screw runs off the contacts. The method of laying out the wooden disk is made clear in the illustration. There are four circles, one for each con- tact. The number of divisions of the plate depends on the number of color combinations desired, the limit being set by the number of strings of lights em- ployed. With four strings it is possible to produce 15 different combinations. This is done by using each string separately, and then two or more strings in combination. The screws are set in the disk in the same manner as in the spring holders ex- cept that there are no connections, the screws serving merely to connect the upper and lower spring contacts between which it passes. The speed of the disk is reduced as far as possible with the adjust- ment provided on the machine and the friction of the contact reduces it to a still greater degree. The method of arranging the lights is optional. All the lights on one string may be of the same color, or they may be different. Experiment will determine which gives the most pleasing effect in the decoration of any given tree.

Making an Auto Steering Wheel Spider and Hub [F A larger steering wheel is to be fitted to an automobile, or a wheel has to be made for a homemade motor vehicle, the construction of the spider and hub can be easily accomplished. Secure a wooden rim of the diameter desired and then turn up a piece of cold-rolled steel shafting to the proper diameter to form the hub. WOOD RIM ----,

How the hub and arms are made and put together to hold the wooden wheel Slot it in three places, as shown, the slots being just deep enough to give the spider arms a Solid anchorage. The hub should have a keyway to fasten the wheel to the steering column. The arms proper are made of flat steel stock, neatly tapered off. Three arms, if strong enough, are sufficient, although four lighter ones also make -a-good looking job. A hole for a wood screw is drilled and countersunk in the eye end of each; fle other end is drilled for 14-in. oval counter- sunk head screws. The arms are then bent to the required angle. The corners of the arms should be neatly beveled off and the metal painted with black enamel.

Earn Big Money Learn the Automobile U 0

WN STATION

work necessary on the thirteen mil- lion automobiles in the U.S. A. alone! Elec- trical systems, engines, etc., tires to be repaired and replaced.

to be maintained, batteries and

NO TTipenT TIRE Think of the wonderful opportunities for a shop of your own. There are mot nearly enough trained men to do this work right. Why not get some of this hued ) good money yourself? Thousands of graduates of the Michigan State Automobile School (all over the world) are now successful in good jobs or in shops of their own. Age, education, or experience make no difference. Youcan be successful too if you will get M. S. A. S. practical training now. Unlimited Opportunities For Trained Men Get the right start. Come to Detroit and learn the business thoroughly. Study automobiles, engines, trucks, auto electricity, tractors, farm lighting plants. Learn on best equipment, all in good condition, up- to-date. Our engines are ready to run, our electrical systems are kept in A-1 condition,—no useless junk to look at but not fit to learn on. You are taught under factory endorsed methods by expert instructors. A thorough complete course that slights nothing. Plenty of time in every department to learn right. R. L. Beck, Pa., writes: ‘‘My wages have been increased What Our Graduates Say 300% in two years since getting M. S. A. S. training.” M. B. Gill, Idaho: “‘I am now foreman of my shop, have doubled my salary and am turning out far better work than before I took your course."” J. I. Mayes, Kansas: “‘I have saved $100 every month since taking your course.’’ Vanderbie, Holland, Michigan, writes: “We have the Durant agency and are the busiest place in Holland.”” Thomas, Pa., ‘Three months after graduating I became foreman of the Dodge garage at $200 a month.”” Nelson, N. Y., (seventeen years old when he graduated) writes: “I have five men work- ing for me.’’ Greve, California, ‘Last year’s business bought us a nice little home and we have started buying another this year.’’ These are not exceptions. They are just average fellows, no better than you. You can do it too. Come To DETROIT—The Auto Center Here you have wonderful advantages. Visit the great plants, Ford, Dodge Cadillac, Packard, Lincoln, Hupp, Hudson, Studebaker, Paige, Buick, Rickenbacker, many others. These great companies fully endorse this school altho they have no business connection with it whatever. Their letters of recom- mendation have been written by their executives who have seen our school, inspected our methods, em- ployed our graduates, and furnished us equipment for instruction. ’ They tell you to come here because they know our course is right. This is the only aut bile sch in the world which has this endorse-

ment. It all means real opportunity to you to get ahead. Packard says: “We recommend M.- S. A. S. in every particular.” Dodge: "A diploma from M. S. A. S. helps get jobs with auto dealers." Cadillac: “Most complete school in the country.’ Others say the same. Take their ad forever after for your Be A TRAINED MAN,—SUCC d for it and you will be sure you're right. Be MS A. Ss. training. START NOW! M.S. A.S. MONEY BACK GUARANTEE We guarantee to qualify you for a position as chauffeur, repair man, demonstrator, auto siocteicinns. garage man, automobile dealer, tractor mechanic and operator, or farm ting expert, paying from MICHIGAN STATE AUTOMOBILE SCHOOL ligh $1500 to a year.or refund The ‘‘Old Reliable” School in Detroit, the Auto try. your money. Autos, Auto- We Teach: ity, Center. Endorsed by the Auto Indus’ ejectholty A. G. ZELLER, President, Trucks, Tractors, Tire Repair- 592 Auto Bidg. Detroit, Michigan ing, Battery Repairing, Weld- PeF SSS SS SESS FSSC ssseueuses irig, Machine Shop. nd the a . a Mail Coupon Today coupon to day for our big, fully illustrated catalog. : Michigan State Automobile School , 592 Auto Bidg., Detroit, Mich, s Gentlemen: s Without expense or obligation to me, please send s your big catalog and tell me more about the oppor- g tunities for me in the automobile business.

© NO osscde denne i cckcccccdthns sent tA ied oce > sonncthane woacmaitemieaon. * PO 8c, otic big =c <didd poate ~ aaa ethew State..... * (Do you wish to start your M. S. A. S. training

See top of page 8 in front $25.00 in PRIZES vet tortnis A green COMPLETE The Finest Tubular Skate and Shoe Made Used by the World’s Greatest Amateur and Professional Skaters. For Sale by All or Direct from Factory. Factory and Salesroom Dept. PS, 2846 W. North Ave., Chicago, Ill.

=e. —. WORKSHOP 'DEPARTMENT OF POPULAR SCIENCE MONTHLY

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122 To Sales Managers, and otherexecutives or employers of men A sure-fire Christmas remembrance for the ‘“‘go-getters’’ The man-to-man gift should be some- thing of a friendly, masculine sort— and something that doesn’t presume too much upon personal tastes. Men don’t like to be sentenced to wear neck- ties, searf-pins, or other adornments of another’s choosing. As the ladies have not, as yet, taken up pipe-smoking, pipe- tobacco remains ‘‘he- stuff.” Noth- ing up-stage about it, either; since the first Indian pipe-of- peace, tobacco has been a sym- bol of democ- racy and the brotherhood of man. No harm is done if some lucky fellow gets two or three jars of tobacco from different friends. Duplicates are wel- comed. The more, the merrier Christmas. Edgeworth is so generally liked that it’s a safe, sure-fire present for men. In the glass humidor jar it keeps in condi- tion indefinitely. These 16-ounce jars are sold at $1.65 at all tobacco stores; but if your regular dealer hasn’t enough of them, we offer- you this painless plan, just to relieve the pressure on Santa Claus: Send us $1.65 for each pound jar of Edgeworth to be sent out, a list of the names and addresses of those you wish to remember, together with your personal greeting cards. We will pack each jar in an appropriate Christmas box, enclose your card, and send them all off in plenty of time to be delivered before December 25th. Personal—If you are not personally acquainted with Edgeworth, we will be glad to send you free samples—generous helpings both of Edgeworth Plug Slice and Ready Rubbed. Kindly address Larus & Brother Company, 59 South 21st Street, Rich- mond, Va. If. you will also include on your postcard the name and address of your regular tobacco dealer, your courtesy will be appreciated. To Retail Tobacco Merchants: If your jobber cahnot 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. HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE Building a Realistic Toy Theater By Ernest Bade, Ph.D. T IS Christmas and the room is dark. A square of light is seen through the door; this reveals a miniature stage. Slowly the curtain rises. A tropical shore is seen in the white light of the Southern sun. The sky assumes the fiery hues of a tropical sunset. The sun sinks below the horizon, while a rosy light ripples upon the quiet ocean swell. The waves move! Slowly the scene grows darkcr, and the curtain falls. Such is a scene that can be played upon this tiny stage. A number of settings arranged with tiny cardboard figures will illustrate any play or story, such as “Robinson Crusoe” or “The Sleeping Beauty.” First obtain or make a box approx- imately 5 in. high, 12 in. long, and 14 in. Setting up the two stage Sneen which rest in sockets fn th box wide. The lid is hinged at the top of one of the wide and long sides, but before the hinges are attached, make two light squares, each open on one side, as shown. Use thin strips of wood for them. The larger one is made so that it just fits within the box, while the smaller is about 4 in. shorter but just as wide. Next cut two slits in the front of the box so that the tall U-shaped, wooden frame fits snugly, and place a little bracket on the bottom of the box so that the frame will be held firmly. Do the same at the back of the box for the shorter U. Three parallel grooves are then cut into the top of the box cover. These are 14-in. wide and are placed at equal distances from each other. The first is placed about 1 in. from the back of the box, the second two thirds of the’ way from the front and the last one third of the distance from the front. Now fasten the hinges to the box and place the legs of the two U-shaped pieces in their holes, the larger one being, of course, in front. Cut two strips of wood so that they just fit between the two frames, and also groove these to correspond with the grooves on the stage. These two braces or bars are then provided with sheet-tin hooks taken from a tin box. Eyes to fit these hooks are fastened to the top of the uprights. This completes the woodwork. For the proscenium use 2 streng, stiff piece of cardboard or wallboard. Care- fully paste some wallpaper, pictures, or (Continued on page 123) MONTHLY The New Gibson Tenor Banjo is featured in Bob Miller’s Steamer Idlewild Orchestra Play the NEW Mastertone The new Gibson Tenor Banjo, preferred by players who know famous dance and cause of its marvelous tone, ‘ is now being adopted by recording orchestras be- ‘easy playing” and absolute dependability. All the tang of real banjo tone with clusive Tone the man all the kr added musical quality, ing power and vibrancy, due to the ex- onto, athechmente ate ane SCIENTIFICALLY CO. mal — world’s sending sas ted instrumen: in making this supreme instrument. BASY PAYMENTS onany Gieon instrument ‘ul carry- Gibson Rim and Ball “tig Tube construction, the bi, rovement ever made in banjos. re Tone Projector takes place of oes and gives beng ard d easier pla: and eliminates Pipying Sibson ‘fe few of knowledge and experience of the nufacturers of fret- has been oe Z erage Tenor en tar Banjo, Cell Bacio, Mandolin. Mandola, Mando- lo, Guitar, uitar and Mando Bass. Send Coupon NOW or Free Book ot ont complete in- “formation, mentioning instru- tN ERE. GIBSON MANDOLIN-GUITAR Co. 1205 Parsons St. Kalamazoo, Mich. Please send me complete information about (Instrument) Name. Street or R. R. P. O Pek Hf interested in becoming a teacher-agent check ( ) 164 dieuent "Bde. Decent Ae U.S.A. _EABN MONEY AT system, pay you cash reece work, Write P YOU an make 53 $6 wey in your spur ne can | We Smmtruce you by ur, ew simple Dir = WEST- sy 0 td SHOW CARD SERVICE LIMITED 63 Colbenne Building (Oita each w anh yoo od wegen Toronto, Can. 124 HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY qiitionmieny: ewemie Septet rig, rit TRE eS a si

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peseraiy sebdenionti Q

| Building a Realistic Toy Theater

street

(Continued from page 122) designs from magazines, and a few colored papers together to make some kind of an -ornamental arrangement around this frame, leaving a clear stage opening 8 in. wide and 7 in. high, which is’later cut out. It is well to use two pieces of cardboard for the arch, joining them together with a strip of calico pasted on the back. The proscenium is made from carde- board and covered with wallpaper and colored cutouts

This will permit folding so that the pro- scenium can be packed away in the box when the stage is to be put away. The front of the box is concealed by an- other cardboard strip 5 in. high and about 20 in. long. This is also in two parts so that it will fit into the box. The curtain is just back of the prosce- nium and consists of a piece of cloth with a picture pasted on it. It is weighted on the bottom with one or two pieces of iron wire. Near oneend a cord is firmly fast- ened for raising or lowering the curtain, the cord winding around the roller. The roller is held in place like any window- curtain shade. The side scenes and backgrounds can now be made. Each background must have two side scenes to match, cut from cardboard about 11 in. long and 9 in. high. The opening in each side scene may be the same as the stage opening, that is, 7 by 8 in., although it is better to make it about 1 in. larger each way. The backgrounds also are 9 by 11 in. They may consist of some sim- ple scene cut from magazines or books, showing rural land- scapes, in- teriors,

scenes, har- bors, and the _ like. The back- ground must fit in the last. groove of the stage and of the upper bars; the side scenes fit the other grooves, so that all can be pushed in and pulled out easily. When a number of scenes have been prepared, a few figures can be mounted on cardboard and cut out. Placed on the stage in small wire brackets, small plays (Turn to.page 124) The complete stage, showi: the Shale background a | le scenes

Diteenesntiil

day for Ill

HOME WORKSHOP ‘DEPARTMENT OF POPULAR SCIENCE MONTHLY Wouldnt you like to wor this LO ton | yeier at it! Aslight pull of a lever and away up into the air it were ten pounds. SOrOx © Kx you like. Et ae Se SOOOCOOOL ©, pleasure. WE o SOO, x

— ttt e te ee ee 8 lf Q S

swings 10 tons as though Every bit of the fun of working this crane is yours, if you have Meccano. You see, Meccano parts are real engineering parts and that makes your crane work just like the bigger ones. whenever you want to, you can take your crane to pieces and build a tower, a battleship, a bridge, a fire-escape—anything MECCANO Toy Engineering for Boys Send for This New Meccano Book It describes Meccano and tells interesting things about model building. Every page a Free, if you send names and ad- dresses of yourself and three chums. No. 65 after your own name for reference.

And just

Put

MECCANO PRICES No. 00 Outfit builds 40 models—$1.00 No.0 “ “nm * —20 Nol “ “ 105 = 6 6 2 os «4s 24 2 2 gd

LLL.

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E SENSATIONAL SAL.

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| MAKE, MONEY -: AT HOME 15 to 50 Dollars a Week for Your Spare Time. No Convaceing. Ex- ence Unnecessary. ite to- ustra Booklet and Free Working Outfit. UNITED SHOW CARD STUDIOS, 807 Dinan Bidg., Detroit, Mich.

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

LADIES RING a ,/

Harold Lachman Co., v2.33 "Sess.

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124 WS WN \\: WY ~\ AN AORN Zs AA See | WW NN RAY RWS SS RRA \ ee | inYour Own Home You may now have an: any known musical instrument for a week’s free trial in your own home. Play it as muchas you wish. See how easy it isto learn. There is no obligation to buy; noexpense forthetrial. You may return the instrument at the end of a week if you decide not to keep it. }} Wurlitzer instruments are known the i} world over for unusual tone quality and 1] excellence of workmanship. They are used by the greatest musicians, bands, and orchestras. Easy Payments If you aside to bay, the Wariner pion males it ony for you to own the instrument you Payments are conveniently in —e monthly sums--a few cents a will pay. Special combination offers on complete outfits — velvet lined case, = z you peed” — in- structor, etc. — everything you need at prac- tically ast cost of the instrument alone. , epee am jor mnomm mentation 8 ee es trai in tee’ colors. Gives you low- rices an the arli The Rudolph Wurlitzer Co., Dept. 1789 W. 42nd St., New York © 250 ae , absolutely free, nee aoe new illustrated of musienl ine trements SR ene me 5 eae Sy eotrement in myown home at your nse, and Name 2 | 117 E. dis SL, Gacmali 329 So, Wabash Are. Clee oa Stocklon St. San ‘Framcisce catalog any how tke plan seakesit easyfor metobuy. 3 Noobligaton. Address. City.. @ Pe ee netrument (State instrument in which you are interested.) HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Building a Realistic Toy Theater (Continued from page 123) can be performed with these figures. Almost all the backgrounds can be made transparent and quite a number of them can be made movable. A rising moon can be made by cutting a 1-in. strip out of the cardboard sky from the horizon to the top of the picture. Take a piece of black paper about 1 ft. in length and cut it 1 in. wide. In the center cut a small round hole to represent the moon. Paste two strips of cardboard along the cutout in the background, to form a groove for the black paper. Light the back of the stage with a lamp or a flashlight and gently pull the strip of black paper up- ward. This will give the effect of the rising moon. Other effects to be obtained are the lighting up of windows, lightning flashes, twinkling stars, moving waters reflecting the rising moon or setting sun, rainbows, and the like. Elaborate cutouts can be glued to netting, which can be used to aid in many novel stage effects. To increase the effect, small toy electric lights may be added. These can be worked either through a transformer or by a set of batteries. There should be at least two footlights —a blue light and a white light—and two droplights, the first being placed just in front of the first scene and the second in front of the second side scene. By using a dimmer or rheostat connected with the white lights, the lighting can be lowered gradually until the one blue light left burning gives the effect of night. These lighting devices greatly increase the charm of the model theater, especially if the backgrounds have been made transparent. Yardstick Set in Bench Serves for Rough Measurements [2 EFEATED handling of a rule at the woodworking bench can be avoided to some extent by inlaying a yardstick in the top of the bench near the front edge. When the carpenter who devised this method wishes to measure a few feet of ie pn 5 f, % . Siseitenots a length of molding with a ’ ruler inlaid in the bench top stock, particularly of the molding and | lighter materials which he mostly handles, he simply runs it close against his bench parallel with the ruler and marks off the length.—FRANK -V. FAULHABER, Brooklyn, N. Y. Copyright 1928, Rudolph Wurlitzer Co. SEND NO MONEY ; 2 GENUINE DIAMONDS ss iss Each — Stones-No Chips) Genuine BX 6 MS BY HopeRuby ss seeyiecet ep seiner Can be had in coy x all initials (Old English); also in all lodge em- blems. Send size of jinger and ring will be sent for tuspection. Buffalo a Mitg. Coc, **The Mail-Order House’® A, Brisbane Bidg., Buffalo, N. ¥. THE NEWEST SIMORE TOOL « »”? eng oe e Combination KNIFE and screwdriver -- a keen ateel knife blade, and two screwdriver blades in the handle -- blades selected and pro- duced by gravity, the knife blade can never fold or turn and injure you, change blades in two seconds. % ThisCombination muta and screwdriver sent you post id for only le .25, check o = ney order. 225 tool ofits kind, ideal for radio — = fans, carpenters, motorists, PREPAID for household use. Order TODAY. Dealers are invited to write for proposition on this and other Simore tools Dept. 512 The New Ace Type 3 B A new member of the Ace family selling for which is equal to a combination of the Ace T and the Ace two-stage amplifier. Like the Ace V it is manufactured under Armstrong U. S. Patent No. 1,113,149. This set is new, but months of re- search work have brought it to a high degree of perfection. Out-performs receiving sets costing great deal more. A filament switch eliminates ne- cessity of turning out rheostats when set is not in use. A person hearing a broadcasting station pe turn off the set by throwing switch and come later without retuning. A telephone jack is between first and second stage of amplification. This is for a use of who desire to use head phones of loud speaker. Crosley Multistats, universal fila- ment pons se rheostats for all makes of Price $50 : ? tubes, also are used in the Type 3B. The Precision Equipment Company Powel Crosley Jr., Pres. 1217 Vandalia Avenue, Cincinnati, Ohio 4 FREE RADIO BOOKI ; An easily understood explanation of Radio written by Powel Caer re fer President of Crosley Mfg. Cincinnati, and The Decor Equipment Co., Cincinnati. Write today for this Booklet. Ca CROSLEY MANUFACTURING CO. 2217 Alfred St. Cincinnati, O. HOME WORKSHUP DEPARTMENT OF POPULAR SCIENCE MONTHLY & SKIDMORE MFG. CO. THE SIMON pig —e wm «st Th =

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one oe Baie an teller

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

Fairy Figures Form Novel Christmas-Tree Stand (ERIEEAAS trees in Europe, where so many of our Yuletide customs origi- nated, are usually gathered and sold with the roots attached. They are then set up in a large pot or tub, according to size. This has advantages, from a picturesque standpoint, over the American practice of mounting Christmas trees on a stand of two crossed sticks. More novel than either method is to have some pixies or fairies holding the tree upright. Three or four of these, as shown in the accompanying illustration, can be cut from thin wood (three-ply paneling is best) with a fretsaw or a sharp

Cut from plywood and gaily painted, these figures make an attractive support for the Yule Tree knife and painted as decoratively as possible. These figures do not require a solid base; a diagonal brace between them will be ample. Flat pieces may be nailed to their backs, if desired, to make it easier to attach them to the tree trunk. Another method is to make the figures like big dolls, but with stiff wire along the legs and up the backs, passing out through the shoulders and round the stem of the tree, with perhaps a sash right around them all for a lower support. Make the figures large enough to form a steady support, say 18 in. high for a 6-ft. tree.—E. A. M.

FEATURES FOR JANUARY O MATTER what | particular aspect of the home workshop interests you most, you will find ex- ceptionally useful articles relating to it in next month’s Poputar ScrENcE MonTHLy. First there are the prize-winning letters in the recent tool contest. Then, for the woodworker, there are articles on how to build an ideal home workshop wall cabinet for tools and a combination bench hook, miter block, and shooting board; on weatherstripping your home, and on rebuilding a pedestal dining table. interested in outdoor sports will find arate it ws ood plans for a non-tipping bo and a racing skate sail. ’ For the children, there is a child’s kitchen cabinet; for the typist, a cheap method for making rubber keys. Similarly, for the autoist, the radio fan, and the metal worker, there is a great wealth af helpful material.

American Flyer’ Railroads and “Structo” Automobiles Here’s great news, boys and girls—this year we have made more “American Flyers’’ than ever before, so every Toy Store in your town can get a suppiy, We are also selling “‘Structo Autos’’—you can buy them ‘‘Ready Buil¢’’ or you can get them “‘Knocke ! Down’’ and put the parts together yourself. Remember, The American Flyer Company GUARANTEES all trains to be electrically and mechanically perfect.. If any Toy Store hasn’t got the “‘American Flyer or “‘Structo’”’ outfit that you want we will ship any of the trains, autos or equip- ment illustrated, post-paid on receipt of cash.

A full line of both electrically and mechanically operated ‘American Flyer” Miniature Railroads at t.c best Toy Stores. Take this Magazine to vour Tey ) ave and ask to see these Trains

a Lf =| Lk a8 | oie es 4 wowmmmeene Fese LUT Nemeneeenee Ne se 8 ae No. 1221—Electric Engine, with headlight, 8 inches, 3 double-truck cars, 614 inches, 14 pieces of track; semaphore, station, tunnel; rheostat and track connection. Length fas of train, 31 inches. Price, delivered, $11.00

No. 2—Mechanical Engine, with brake and piston rods, 6% inches, tender 4 inches, cars 54% a nes, 7

gage car has sliding doors; 10 pieces of track; No. 44 track, 103 inches; length of train, 24}4 inches. PA - °° delivered, $2.65 STRUCTO” i Rentoaee aterpillar | & Be. 33 ” Tractor STRUCTO Complete as De Luxe Auto pr Redinedge oF Complete con- harrow attached 1 struction outfit Operated by a —all parts ready poweees motor. ut tcgether. No. 13—Mechan- (-FREE A. G. Mohaupt, Radio Engineer, -<™ os id 4, a Se eee! q17

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ee ee 126 HOME WORKSHUP DEPARTMENT OF POPULAR SCIENCE MONTHLY What Moler System Means to You Everywhere there is a big demand for Moler trained barbers. Our national ad- vertising educates the public to the NEW EASY TRADE Lifts Men out of Small Pay Jobs Are you Satisfied with your Job ? Have You got all the Money you Want ? if Not, “a for My Big New Free Bock ind learn how to Earn $50 to $150 Each Week No matter what you are doing now, no matter how much your present earning is, our amazing new system of training for the barbering profession is a sure and steady source of bigger earnings. Learn in a Few Weeks—Double Your Income Put yourself in the big pay class. Get expert training under the Moler System experts. master of a trade in which there are not enough highly skilled men to fill the jobs now open. The Moler System gives you a practical, super-training in barbering. Just a few hours a week for a very short period and you get a thorough training under the personal direction of Moler experts. Fis Paid Profession Moler System. It makes you the sought- after barber in your locality. It keeps your chairs filled and turns profits into your pocket. of a national institution which assures steady, profitable business. Through no other method can you get this. Easy Work—Always Busy— Big Pa commissions in addition to salaries. Moler System graduates are in great de- mand and have no trouble in securing good jobs. Start today—in a few short weeks you'll be earning $50 to $150 safety, cleanliness and comfort of the a week. ” ” s® Our illustrated book that we mail free tells how we enable ‘ou to earn while 1 You as graduate area part Obs ‘how we on tonne we take you just as you are, make your life’s work easier, better ying and more independent. cities. We have one near you. As owner and chief instructor of the Moler System, I know y exactly the kind of training a man needs to get the steady busirfess and big earnings. A trace that enables you to traveland $3,500t see the world—one that pays in tips and in their owe. Write Today! Nearest Branch Moler System of Colleges 33 Branches Moler System of Colleges ° : 1ST Third Ave. New York, N.Y. 110 S, 14th St, Omaha, Neb. Pree SE 0102). oo aps vane te 20 40 105 S. Wells St. — Chicago, Ill. 513 E. Water St. Milwaukee, Wis. ‘(WRITE NEAREST BRANCH) } 810N. Gth St. St. Louis, Mo. 1005 Canal St. w Orleans, Please send without obligation your Free 544 Main St. Kansas City, Me. 23 N. Forsyth St. Atlanta, Ga. Booklet C and full information. 206 E. 4th St. Cincinnati, Ohio 80 N. 2nd St. Memphis, Tenn. i 215 Huren Rd. Cleveland, Ohie 910 Main St. Dallas, Texas N 045 Cass Ave. Detroit, Mich. 712 Franklin Ave. Houston, Texas RE id. i ins apenas sos bea Sees y 1229 17th St. Denver, Cole. 727 W. Commerce St., San Antonio, Texas Address 5 ey etre wil SaMins oles se ete a Write for Free Book . how we put you into the best city shop on easy payments. In fact, how We have 33 branch schools in I Give You a Real Training Hundreds of my students are now earning o $8,000 a year. Many own the biggest and best shops Squab Book F REE 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 H St., Melrese Highlands, Mass. @ 4) )\ 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 before enrolling, but worked at the lessons during their spare time and found CARTOONIST Evans’ MetHop “easy to learn’’ and are now making g 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 you cando. 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 Leader Bidg., CLEVELAND, OHIO 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 224 W 39th St. :: ss NEW YORK PRICES cur $50,000.00 Reward Dead or Alive Toronto, Can., Millionaire Missing BE A DEFECTIVE 2¢,2 Finger Print Specialist. Learn Scot- land Yard Methods. Experi- ence not necessary. Write to- day for FREE illustrated booklet United Detective Training Ass’n, 807 Dinan Bidg., Detroit, Mich. A’ tone OR! $3. ond “e easily convert your #13 Heats pat- sed 39} i HE KURMPEL C0. 524 ee A Radio Set for Christmas (Continued from page 80) points of contact with the binding posts, is then used to join the contacts numbered 1 of rheostats D and Q with binding post U:. The No. 2 contact post. of rheostat D is then connected with the remaining F terminal of socket H, while another wire is used to connect the remaining F ter- minals of sockets N and T with contact post No. 2 of rheostat Q. By means of these connections, rheostat D is used to control the filament current of the de- tector tube in socket H, while rheostat Q controls the filament current of both am- plifier tubes. Now connect the P terminal of trans- former J with the inside jack spring of jack J, which makes contact with the outside spring, to which one of the leads from rotor winding L is connected. The other inside terminal of the jack is con- nected with the B terminal of trans- former J and the remaining outside ter- minal is connected with binding post Us. The F terminal of transformer J is connected with binding post U,, and the G terminal of the transformer with ter- minal G of socket N. How to Wire the Jacks The P terminal of socket N is connected with the top outside spring of jack P and the inside spring of the jack, which makes contact with this spring, is connected with the P terminal of transformer O. Binding post Us is connected with the bottom out- side spring of the jack, while the inside spring, which makes contact with it, is connected with the B terminal of trans- former O. The G terminal of transformer O is then connected with the G termina! of socket T, and the F terminal of the same trans- former is connected with binding post Us. The wiring of the set is completed by con- necting the top spring of jack S with the P terminal of socket T and the bottom spring of the jack should be connected with binding post U7. The type of A battery employed will, naturally vary with the type of tubes that are used. Best results will be obtained when a soft six-volt tube of the UV-200 or C-300 type is used as a detector and hard tubes of the C-301-A or UV-201-A types are used as amplifiers. If a soft tube is used as a detector, rheostat D should be of the Vernier type. In this particular set, however, dry cell tubes of the UV-199 or C-299 type are used throughout and give excellent results, both- for distance and strength of signals. The minus or negative terminal of the A battery is connected with U:. The positive of the A, the negative of the B, and the positive of the C batteries are connected with binding post Us. If a soft tube is used as a detector, the 22 «- volt terminal of the B battery is connected with binding post Us, while if one of the hard tubes is used as a detector tube, the 45-volt terminal of the B battery should be connected with that binding post. The leads from binding posts U; and Ue are tried on various terminals of the C battery until the best value of the grid (Continued on page 127) sed a

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as sts, is bered y post eostat ling F r Wire F ter- ntact ans of ed to ie de- stat Q h am- trans- ng of h the leads The 3 con- trans- e ter- st U. ’. I is d the h ter- ected P and nakes 1 with nding n out- inside it, is trans- ; then ocket trans- st U 6. y con- th the ottom ected 1 will, s that ained 200 or hard types ibe is ild be icular V-199 t and tance of the The he B, S are If a 22 le- ected of the e, the hould , and the C > grid A Radio Set for Christmas (Continued from page 126) bias on the grids of the amplifier tubes is obtained. Binding posts Us and U; are tried on various terminals of the B battery varying from 45 to 90 volts. The operation of the set is very simple. The adjustment of the wave length of the primary circuit is obtained by adjusting the tap switch E and the condenser C. The wave length of the secondary is ad- justed by means of the condenser T. The variation of coupling between the second- ary and the primary circuits is obtained by turning the rotor M, while regeneration is controlled by turning the rotor L. Radio Inductance Switch Has Hidden Contact Points HE radio inductance switch _illus- trated has all contact points at the back of the panel. The form on which the switch points are mounted is cut from fiber, or seasoned wood coated with hot paraffin. Its FIBER SOLDER SwiTCr ARM - TO NUT This switch is mounted on the panel so that no screws or switchpoints are visible dimensions depend upon the number of contact points. Two holes are drilled for the machine screws that hold the switch clamped to the back of the panel and a recess is also cut to make room for the nut that fastens the switch in place. The arm is sweated to the nut and shaft to make the opera- tion thoroughly certain. Quickly Made Hangers that Save Closet Space "TROUSER hangers of the usual type occupy a good deal of space when ‘hung on hooks in a clothes closet. Much of this space can be saved by making hangers as shown. They lie flat and the room they occupy, whether in use or not, is almost neg- BOARD OR WALL-~ + ligible. fest eng The hanger _—— . proper consists of a piece of hardwood about % in thick, 1 in. ‘ wide, and 10 in. How the hanger is made Jong with a hole bored in one end. The hanger is attached by means of a loose-fitting roundhead screw to the wooden strip that supports the closet shelf or to the edge of the shelf itself—anywhere it will go. The other end of the strip is fastened under a screw hook. HOME WORKSHOP DEPARTMENT OF POPULAR ‘SCIENCE MONTHLY Tube Efficiency Is Trebled. With Erla Synchronizing Tronsioraee Vacuum tube doing double duty as am- plifier of received Ve fashe cecki as relay or single- andreflexedr f.cur- duty amplifier rents,withErlasyn- chronizing radio transformer Perfect synchronization of received and reflex of currents make Erla radio transformers indispensable in reflex work. ist, $5 Rectified radio frequ and vohanal Gedio (ssweaing vadkvantnaliiee Exla audio rmers. List Price, $5 cuits. is uniqu for reflex work. List, $1 = £ERLA Dept. F Jelbove~Unenampled sales a a are crea! leadership in res and manufacturing. Write for liberal terms an unts Vacuum tube doing ceived and reflexed Hi | radio frequency “an currents, with Erla : synchronizing ra- dio and audio transformers bitten oh tered \\E 4 Responsible for the unduplicated efficiency of Erla reflex circuits is a basic Erla discovery of vital and far reaching importance. Discordance and instability in reflex circuits, it has been ascertained, are due directly to failure of transformers properly tosynchronize received and reflexed ‘currents having the same phase characteristics, in their simultaneous passage through amplifying tubes, Obviously, if the lag between such currents were as much as 180°, forces would be zero, resulting in an absolute canceling of signal strength. Any intermediate lag, on the other hand, results inevitably in the generation of amplified distortion. Erla scientists solved this problem by designing radio and audio transformers of an entirely new and special type, positively assuring perfect syn- chronization of received and reflexed radio fre- quency, as well as rectified radio and reflexed audio frequency currents, This achievement, enabling vacuum tubes suc- cessfully to do triple duty, as simultaneous amplifiers of radio frequency, reflexed radio fré- quency and reflexed audio frequency currents, marks one of the most importarit advancements of recent years. For complete details, ask your dealer for Erla Bulletin No. 14, describing and illustrating per- fected Erla one, two and three-tube reflex cir- Or write us, giving your dealer’s name. Electrical Research Laboratories the net result of their opposing 2515 Michigan Ave., Chicago $25.00 in PRIZE - be of page 8 in front book for details “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 Ihad themin, myself, only that I hear all right.” The Morley Phone for the DEAF i to the care what Invisib! ’ eyes. Invisible tose, ond parmiges._ Anyone it. Over one hundred thoo- THE MORLEY Co., Det. 7 TOT, 26 8. 19th Street, Phit:deiphia ee eat Oe ae —- amntimmmn@aw eo a2tao% eeEeweee we Car Owners Wanted

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Let me send you this great book. Learn all about the wonderful electrical industry and how you can easily learn to earn $3,500 to $10,000 a year. BE A CERTIFICATED Electrical Expert EARN $70 to $200 A WEEK No matter what kind of work you are doing now, or how much you earn, Electricity offers you more— a better job and bigger Pay is waiting for you. Trained Electrical Experts (not common screw driver electricians) are in great demand at the high- est salaries-ever known. The opportunities for ad- vancement and a real success are amazing. The enormous growth of the electrical industry snaps up men faster than they can be trained. Fo aer $9,500.00 to $10,000.00 tear I will train you at home in your spare time to earn this fine big pay. In just afew short months you will be ready for a wonderful job that I will help you get. Lack of education or experience doesn’t bar anyone. My simplified, up-to-the-minute, easily learned course, backed up with my 20 years of en- gineering experience, guarantees your success. * OUTFIT FREE Electrical Tools and Material I will give you free a whole outfit of electrical tools, material, measuring instruments and a real electric moter—not toys, but the real things such as no other school has ever offered before. I will start you right in after your first few lessons doing practical werk, in a practical way—work that will By you extra money while you are learning and from $3,500 to $10,000 a year when you are trained. SATISFACTION GUARANTEED I don’t merely promise you these things—I guarantee them. I send you a signed bond guaranteeing to return your whole tuition fee—every penny you pay me—if you are not 100% satisfied after finishing my course. Mail Coupon Now Send me this coupon and I will mail you a $45.50 credit check (for limited time only). My big illustrated book and the “Vital Facts of Electrical Machinery,” including my Free Outfit Offer. Mail the coupon today while the special reduced price is in effect. L. L. COOKE, Chief Engineer Chicago Engineering Works Dept. 539 CHICAGO Se te ee ee eS ee eae, 1 L. L. COOKE, Chief Engineer t 1 Chicago Engineering Works } Dept. 539, 2150 Lawrence Ave., Chicago, Ill. ' t Send me free and without oes on my part | your book ‘‘How to Become an Electrical Expert,” i J your Free Outfit Offer, Proof Lesson, and all particu- , lars of your course, including the $45.50 Credit Check. i ! ne REE eal ag Ra Rg AIRE a ER 9. A ! f ' ES ei a 2 i i ei ard: ee ee a ee eet E oe oe ow oe oe oe ee we ee we ow oe ee oe ee oe oe ow os ol Heating Plant Repairs that Will Save You Coal By Dale R. Van Horn ITH coal at top prices this winter, it will pay you to see that your house- heating plant is in first class condition. To get every dollar’s worth of heat out of the coal, the heating system must be in good repair. It has been proved time and again that uncovered pipes, or pipes from which the insulating ma- terial has been re broken, some- Fig. 1. Mixing asbestos times resylt in cement with water for a fuel bill 20 or a 25 per cent higher than otherwise would be necessary. Burned-out flues and disintegrating chimneys are a fire hazard, yet the flue pipes are often allowed to rust or corrode clear through in spots before they are re- placed. Broken grates, besides prevent- ing perfect combustion, often allow small unburned chunks of coal to drop into the ashpit, adding to the fuel cost. These are only a few of the urgent reasons why the heating plant should be thoroughly in- spected each year. The purpose of pipe covering is to pre- vent heat losses as much as possible before the heat reaches the radiators or the hot- air registers. The common practice is to cover hot-air pipes with sheet asbestos or cloth covered with an asbestos prepara- tion, and hot water and steam pipes with either honeycomb material, especially prepared for the purpose, or an insulating composition. It is well to remember, however, that dead air spaces are the best insulators of relatively low temperatures, and solid insulation is best for pipe at relatively high temperatures. Hot-air flues ought, therefore, to be (Continued on page 129) 128 HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 21 Jewel ~ Extra thin STUDEBAKER The Insured Watch ENT FOR O@ Down | Only $1.00! The balance in easy monthly payments. You get the famous Stude- baker 21 Jewel Watch—Insured fora lifetime; a choice of 44new Art Beauty Cases; 8adjustments, including heat, cold, isochronism and 5 positions—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 Studcbaker 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 book—FREE! See the newest, beautiful, advance styles in Stude- baker Art Beauty Cases and 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, Me 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. Dept. 2312, South Bend, Ind. TUD WATCH CO. a ty South Bend, Indiana Please send me your Free Book of Advance Watch Styles and particulars of your $1.00 down offer. Name eeeeeeeeeeeeeeeeeeeeeeeeeeeeee eee eeeee Address...cccccceses oe. 600 0 cotceed cece suees City. ...0. deken en tem bin . State.. eeeeeseece ———— HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY DON’T WEAR A TRUSS BE COMFORTABLE— Wear the Broo! ppliance, the modern scientific invention which ives rupture sufferers f ef. It has no obnoxious springs, pads, Automatie Air Cushions and draw No salves or plasters. Durable. Sent on trial to prove its worth. Be- were of attations, Look 5 trade-snark beari and signature of C. E. Brooks whic pears on ev Ap fiance, None other genuine, } Full information ‘and booklet sent free in plain, sealed envelope. BROOKS APPLIANCE CO., 230 State St., Marshall, Mich. The Real Estate Educator. This book gives a most comprehensive yet most concise | arrangement of useful facts about buying, selling, leasing and sub-letting of Real Estate, contracting, for erection or repairs, mortgaging, transferring, insuring, etc. Cloth, 256 es. Price $2.00, postpaid. Popular Science Monthly, 225 West 39th Street, New York City. a

Page 107

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HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

Heating Plant Repairs (Continued from page 128) covered with corrugated insulating ma- terial or asbestos at least 14 in. thick. They can, nevertheless, be insulated to a considerable degree with muslin cut to the proper width, the edges sewn together, and then covered with asbestos cement. The cement is mixed with enough water so that it can be applied with a brush. Two or three coats should be given. A

Fig. This tin-patched smoke pipe echads a makeshift repair that is wasteful and hazardous still simpler and less costly process is to paste asbestos paper sheets over the pipes. Steam or hot-water pipes can be covered with asbestos cement with little difficulty. The cement is mixed (Fig. 1) to a sloppy consistency. A square of tin, free from rust, such as from a tomato can, is then wrapped about the pipe in the form of a cone (Fig. 2) with the largest opening up- ward (or, if the pipe lies horizontally, forward). With one hand the cement is forced into this, and with the other the tin is slowly moved along. The covering comes out of the small end in a compact, smooth mass. While it will not stand rough usage, the cement will remain in- definitely if left alone. Such a covering, even for large pipes, will not cost more than one or two cents a foot for material. By wrapping cloth about the insulation immediately after it is applied and press- ing the fabric into the cement, a more durable surface will be obtained. An easier method is to buy honeycomb insulation in sections. These are at- tached by strips of cloth or tin collars. Even the most expensive covering, when applied by high-priced labor, is an econ- omy because of the coal it will save. Covered pipes also prevent possible radiator repair bills. Last winter an im- proper in- stallation cost the writer $25. The pipes leading toa north bed- room radi- ator were of small diameter and un- covered. The total distance from the boiler was 34 ft. During a cold snap this radiator froze and burst five sections because of the excessive cooling of the water before it reached the radia- tor. The pipes should have been at least 1} in. in diameter and covered.

Fig. 4. Pasabline worn boiler insulation with cement

(Turn to page 130)

TOM BROWN Six Brown Brothers Saxophone Sextet Victor Records

BEN SELVIN Director Selvin’s Orchestra Aeolian Vocalion Records

DAN RUSSO Director Oriole Orchestra Bronewiek Reco. ds

Thousands Now Find It Easy to Make Their Own Music Everyone has a perfectly normal desire to produce music, but heretofore people have not had the time nor patience to study — The making of music was the privilege of the talented ew. But now it is different. With this wonderful new Saxophone Buescher has made music a universal accomplishment, and has placed it within the possibility of practically everyone. See How Easy It Is The new Buescher Saxophone is a marvelous instrument. It is one of the most beautiful of all musical instruments—by the range and wealth of its tones it takes the place of almost every other instru- ment—yet it is so perfected and simplified that it is the easiest of all instruments to play With the aid of the fret three lessons, which are sent free (upon re- quest) with each new Saxophone, the scale can be mastered in an hour; in a few weeks you can be playing popular music. Practice is a pleasure because you learn so quickly. You could even take a place in a band or orchestra within 90 days, if you so desired. Wins a Welcome Everywhere You are always welcome with a sweet-toned Buescher Saxophone. Thousands of men and women of all ages, have found it an infallible key to social popularity. For home entertainment, for church, school or lodge affairs, the Saxophone is the most popular and adaptable i in- strument. Saxophone players enjoy, also, many opportunities of earning money. They are always in demand for dance orchestras. Prove What We Say—in Your Own Home You may order any Buescher Saxophone, Cornet, Trumpet, Trom- bone or other Band or Orchestral Instrument and try it six days in our own home. Easy terms of payment may be arranged if pre- erred. Mention ~ ee incerested in and a complete cata- log will be mailed fr: A Resiarkshls Saxophone Book—F ree! We have prepared a very interesting book on the history and de- velopment of the Saxophone. It tells which Saxophone takes violin, cello and bass parts and many other things you would like to know, Also illustrates first lesson. It is sent free on request. Just send a postcard or clip and mail the coupon. BUESCHER BAND INSTRUMENT CO. Everything in Band and Orchestra Instruments 3199 Buescher Block, Elkhart, Ind.

Saxophone THESE FAMOUS SAXOPHONE PLAYERS 1 eqeonioes Band Instrument Co. True Tone 129

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POPULAR SCIENCE MONTHLY

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“We pay him $100 a week” *“ a ND he’s worth every cent of it. Camé here several years ago asking for a job. He got just that—a small job at a small salary. “Then I Sorpot about him—hardly knew he was on the payroll until one day I got a letter from the International Corre- spondence Schools telling me that he had enrolled for a course of home study. It was remarkable the way he went ahead. “We pay him $100 a week now and he’s going to be earning even a larger salary some day. I wish we had more men like him.”

How do you stand when your employer checks up his men for promotion? Does he think of you? Is there any reason why you skould be selected? Ask yi these questions fairly. You-must face them if you expect advancement and more money. One hour after supper each night spent with the I. C. S. in your:own home will prepare you for the position you want in the work you like best. Yes, it will! Put it up to us to prove it. Without cost or obligation, just mark and mail this coupon. ~ INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7664-C, Scranton, Penna. Without cost» or obligation on my part, please tell me how I can qualify for the position or in the subject before which I have marked on X: BUSINESS TRAINING COURSES Business Management Salesmanship Industrial Management Advertising Personnel Organizatior, Better Letters Traffic Management Show Card Lettering Business Law Stenography and Banking and Bankinz Law Business English Accountancy (ine):uing C.P.A. Civil Service Cost Accounting, Railway Mail Clerk Bookkeeping Common School Subjects Private Secretary High School Subjects Spanish O French Dlustrating TECHNICAL AND INDUSTRIAL COURSES

E)<ctrical Engineering Architect Wlectric Lighting Blue Print Reading Mechanical Engineer Contractor 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 Airplane Engines Metallurgy O Mining culture and Poultry Steam Engineering () Radio Mathematics Name.......... Street 8-3-23

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Occupation Persons residing in Canada should send this coupon to the International Correspondence Schools Canadian, Limited, Montreal, Canada The Real Metal Solder in Paste Form SOLDERAL : Introducing Our New SOLDERALL BLOW TORCH of Heayy Solid Brass indispensable in the Home,Garage and to the Electrician. For solder- ing Radio, House Wiring, Jewlery, ignition, Kitchen, Utensils, etc.

Heating Plant Repairs (Continued from page 129) If any part of the sheet-metal smoke pipe to the chimney is rusted through, that section should be replaced. If there is any danger of other portions breaking away within a year or two, the whole sec- tion should be replaced. Never, under any circumstances, should one be satis- fied with a makeshift repair like that shown in Fig. 3. Here a piece of tin has been wrapped about the hole and held with wires, but several openings will hamper the draft and there is always the chance of a spark getting outside and causing damage. The chimney, moreover, should be in- spected from top to bottom. Where the mortar has cracked or a brick worked loose, repair it with a hard plaster of Port- land cement mixed with lime. If the top

i SER Fig. 5. Exposed piping like this is a cer- n indication t pe is being wasted needlessly by the owner of the plant of the chimney has begun to disintegrate, remove the loose brick, take the measure- ments, and build a concrete cap on the ground. The forms are set on a smooth surface, centered, and filled with rich con- crete, with reinforcing at the corners. The top should be beveled. After the con- crete has thoroughly hardened, hoist the cap to the roof and set in place on the chimney top with mortar. Clean out all dirt and soot from the furnace. Inspect the grates and, if neces- sary, replace any worn parts. Go over the covering, patching any places where the asbestos has been worn or- broken off (Fig. 4). Asbestos boiler covering, which can be purchased from any plumbing sup- ply house, is quite adhesive when applied to warm surfaces. Always heat the boiler before using it. If any large surface is to be covered, apply the first coat with a trowel or throw it against the boiler. After the first coat is thoroughly hard, put on a second coat smoothly with a trowel. A good finish can be given by a third coat of one-half Port- land cement and one-half asbestos cement, and this can be improved still further with a coat of white lead and oil paint. Make sure that the gages work prop- erly. Then fill the fuel box with fuel and see if everything goes all right. Specific information regarding any special repairs can be obtained from the dealer from whom the plant was purchased. A heating plant is often condemned when, as a matter of fact, the owner is at fault because of having attempted to save money by putting ir. too small pipes or pipes that were not covered. No heating expert is needed to tell that the heating

plant partly shown in Fig. 5 is wasteful. WeN “ie : | FOR PEND THIS FOR 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. | sample form together with printed instructions will show you just how to work up your evi- dence and establish thesame before filing ap- plication for patent. As regis d patent at- # torneys we represent hundreds ofinventors all over the United States and Canada in the ad- vancement of inventions. schedule of fees willbe found reasonable, ‘The form “Evidence of Conception,” sample; instructions relating to obtaining of patents and schedule of fees ont i request. Ask for them,—a post card: 274 Ouray Bldg. WASHINGTON, D. C. Originators of forms “Evidence of Conception.”

To the Man With an Idea fit I offer a most comprehensive, ex- 4 perienced, efficient service for his prompt, legal protection and the development of his proposition. Send sketch, or model and description, for advice as to cost, search through prior United States patents, etc. Pre- liminary advice gladly furnished with- out charge. My experience and familiarity with various arts, frequently enable me to accurately advise clients as to prob- able patentability before they go to any expense, Booklet of valuable information and form for properly disclosing your idea, free on request. rite today. RICHARD B. OWEN Patent Lawyer 6 Owen Building, Washington, D.C, 2276-D Woolworth Building New York City

Ae I Lk RA ERNACRE TC MRT

HOME WORKSHOP DEPARTME NT OF POPULAR SCIENCE MONTHLY

Page 109

POPULAR SCIENCE MONTHLY 131 [PATENTS ma SPECIAL OFFER FREE, OPINION as To PATENTABLE NATURE EB : saben disclosing an invention, the inventor should write for our blank form ‘‘Record of Invention.”’ ‘This should be signed, witnessed and returned to us with model or sketch and description of the invention; we will give our opinion of its patentable nature. Our Three Books Mailed Free to Inventors Our Illustrated Guide BOOK Chicago, IIL, Office HOW TO OBTAIN A PATENT = berms = Full instructions regarding U. S. Patents. Our Methods, Terms, and 100 Mechani- cal Movements illustrated and described. OUR TRADE MARK BOOK Shows value and necessity of Trade Mark Protection. Information regarding Trade Marks and unfair competition in trade. OUR FOREIGN BOOK We have Direct Agencies in Foreign Countries, secure Foreign Patents in shortest time and lowest cost. ALL COMMUNICATIONS AND DATA STRICTLY CONFIDENTIAL INTERFERENCE AND INFRINGEMENT SUITS PROSECUTED New York Office — a ~~, 4 « q \ — > ¥ >> “2 . Bhi. tin te Aa. a Bee Reo - - y “ « ¥ - von: ERAN Pittsburgh Pa., Office __ Suite 514 Empire Bidg. VICTOR ‘BUILDING’ 724~726 NINTH ST.NW. Philadelphia, Pa., Office _ Suite 714-715 Liberty Bldg. U.S.PATENT OFFICE rof. 5 and Spree eaileeee ae . - View from 9th and F Sts. comer of U. S. Patent Office showing location of Victor Building " ‘ Highest References Prompt Attention Reasonable Terms “, ) VICTOR J. EVANS & CO., Patent Attorneys vest Main Offices: 760. 9th Street, N.W., Washington, D.C. FRE E Gentlemen: Please send me FREE OF] CHARGE your flo., books as described above. > COUPON Name... COC e eee H ere eee EEEEES COC OHHH SELES EEE EEEEEES San Francisco, Cal., Office : PI Ui cti on icc S pi denlinde ois tsene ebhoeteder shane sain : Suite 1010 Hobart Bldg. A lp ee ee ee we ee ee ee ee ee 0 ee es es es eye HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 133 ¥g To Make a Pair of Skis

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Sees seth Cieninaemeeeone eee

x inning Sureof to doubt Himsel His Luck At the Age of 40

¥ A Big Out of Luck Success At the Age of 60 a Down and Wel Out Pivsiles q pared. He planned his mw that never came, could ¢ find plenty of it waiting. % really most important 4 good luck by sending in

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Do You Believe in Luck ? Thousands waste the best years of their life waiting for some “stroke of luck” to make them successful. Two men starting exactly alike as babies with the same kind of attention—then as boys with the same advantages of education—then as oung men feeling around for a start in iie—enek then after the final test as

men, one is a failure, the other a big suc- cess. Isitluck? No indeed. Luck vs. Self The one who succeeded believed in himself. He grabbed his opportunities as he sawthemand made good because he was pre- ogress ote by step and tted himself with special training for the line of 7 work he wanted to follow and liked the best. The other fellow—the failure — blinded by his un- reasoning belief in luck onlysay: *‘That man sure was born lucky.” There Is No Luck Luck is exactly what you makeit. Thereisan old saying—“T hose who have —get.’” The more you go after and get for yourself instead of waiting for “luck” to come, the more good fortune is forced on you. Those who are pa- tiently waiting f or some- thing good toturnupare invariably disappointed in life—those who know that they can make their own good fortune always Stop Idle Dreaming Take action and make your dreams come true. Make up your mind to be a success in that line of work or profession you like best—get the special training that will fit you. Dothisand you will make your own good luck. But remember, the big thing isto be prepared—to have the special training that will enable you to make use of the many oppor- tunities that will surely come your way just as soon as you have un- bounded faithin yourself. Now take the first and step in making your own the coupon. This puts you under no obligation and no agents will bother you. American School Drexel Ave. & 58th St. Dept. G975 Chicago ©AS. 1923 |

you American School, Dept. G 975 Drexel Ave. & 58th St. Chicago Send me full information on how Ican best suc- eee eee ee eeeseeeeeeseseeese ain rite in here what line of work or profession like best) This request is to put me under no obligation and no agents are to bother me. (Use margin of this magazine if you need more space

ce

HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY How to Make a Sportsman’s Pair of Skis By Howard Greene YOU are interested in skiing, which is becoming more popular every win- ter, you can make quite easily a pair of skis that will look well and give excellent sport. The raw material consists of a spruce board 6 ft. 6 in. long, 8 in. wide, and % in. thick. The length is a ‘good average; a tall man will need a little more and a short man a little less. Mark two lines across the board, one 2 ft. from one end and the other 3 ft. 6 in. from the other end. Have the mill or a woodworking shop, if possible, saw a taper from these lines to the ends, so that when planed smooth the board will be \ in. thick at the end of the long taper and 4 in. thick at the end of the short taper. The board next is ripped down the center. Then a groove is cut down the center of each piece, extending to within

a = 0 ‘ 4 a «2. 1 ~ 6-6 ak — a! 3 t —S= 12"—>}-—_——3'6 > i v2 Re — = BOTTOM-” TOP --“y ns ——_| Ee }

- FH ve diagrams showing how a spruce is tapered, cut, gresved and bent . 16 in. of the thin end, which is to be the front. The groove is made on the bottom —that is, the side opposite the tapers. The mill can do this sawing and grooving in a few minutes, but it would take hours to do by hand. Plane and sandpaper the bottoms per- fectly smooth, and smooth up the grooves with sandpaper on a rounded block. Work down the wood on the top of each ski until the edges are rather thin—about half the original thickness—while the center is left almost full thickness. Do this in front of and behind the 12-in. part that has been left the full thickness of the original board. Finish with fine sandpaper and cut the points. The skis are then ready for bend- ing. Make a bending form on a bench or heavy plank, as shown. Soak the wood in very hot water for three or four hours. This may be a problem, but perhaps the bathtub can be used. In that case the full length cannot be immersed at once and it will be necessary to reverse the skis every half hour or so, keeping wet cloths around the exposed wood so that it will not dry. This will prolong the soaking consider- ably. Steaming is better and quicker, and a small steambox fed with steam from a kettle is so easily made and used that it is worth the trouble. Clamp the skis on the form with strips of wood extending across both at once. See that the points are supported for their (Continued on page 133)

CAN YOU think of a simple, practical idea that will fill one of the many ree uests we have on file for new inven- east It may mean a fortune for you, Thousands of thingsare needed Ricut Now. Your brainscan help. Send to- day for our great new book—“‘Invene tions and Trade Marks, Their Protection and Exploitation’’ and learn more about making money from ideas than you ever knew before. It tells many things that are wanted, C00. — @ postal will do— Ot in free.

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To Make a Pair of Skis (Continued from page 132) full width, to avoid splitting while drying. Allowance should be made for the spring- ing back of the wood when removed from the form, say 1 in. extra for the long curve of the body and 114 in. for the point. Allow plenty of time for drying; a week is not too much, and damp weather will retard the drying. When dry, give all but the bottom two coats of spar varnish and rub the bottom with hot beeswax, polish- ing it well with a rag. There are several types of foot harness, and any kind that strikes the fancy may be copied. The one shown, however, METHOD OF BENDING '‘ / PLANK OR BENCH The form for bendi one simple design for the skis and 1e foot harness || 7588 8 mow works very well and is easy to make. The toe straps are fastened at the sides with long brass screws with round heads and copper washers under the heads, or they may be passed through slots cut through the wood. The heel straps are riveted to the toe straps with copper rivets. A pole can be made of either spruce or hard wood; spruce is lighter and strong enough. It may be from 14% to 1% in. in diameter, and of a length to suit the user. A good length is about 5ft. The usual ring may be made from a large, ise VO ry is heavy brass curtain ring, attached to the staff by four leather strips. Wet the leather, pass it around the ring, and rivet - it so that it will hug the ring as tightly i as possible. Bind the other ends of the P strips to the staff with fish-line or the like. ere When the leather is dry, it will shrink ~ and hold hard on the ring. Then give 4? it a good soaking with neat’s-foot oil. : Drive a brass ferrule into the other end of the staff, and put in a long, heavy wood aS screw to the full depth of the threads. oa Cut off the head and file the shank to a sass point. re Cheap Photo Film Clips = XCEL- fom LENT clips aids for photo films = pyncuep can be made NUMBER-~~ ; cheaply from know ordinary brass —_ showcard hang- ape ers. About half L869- the loop of each hanger is cut wonton out, as shown, with a pair of scissors. These hangers may ) be used to suspend films in the tank for development, in the fixing bath, in the oR hay washing tank, and finally on the line for oman] drying. If desired, the hangers can be 24 numbered with steel stamps, so that the films can be readily identified.—J. A. M. $25.00 in Prizes HOME .WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY a er er a TRADE oe 2 8 Oe ee ee oe WIG 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, invention. may be patented, if it involves If You Have Any New Ideas which you feel are useful, practical and novel, take prompt action to protect your rights. arts, or improveme: If you have invented any new machine, or new combination of ew design or NG, rocess, SEND DRAWING. nt, Or any n ODEL OR DESCRIPTION of it for information as to procedure to secure protection. Write Today for Blank Form ‘Record of Inyention’’ USE THE COUPON attached, and immediately upon its receipt I. shall send ou this form to be returned to me with dea; promptly upon receiving your idea and costs. drawing, description or model of your I shall write you fully as to procedure No Charge for Above Information All communications are held in strict confidence. M and thorough attention is given to each case. I offer you e prompt service—b: WRI personal, careful cient, reliable and upon practical experience. Highest references. ased TE TODAY for free book **How to Obtain a Patent.’ This book will ive you valuable information, and it may save you much time and effort. Send or it NOW. Trade Marks. Write me freely, fran My ractice is devoted godntoety to United States and Foreign Patents and M y and with full confidence; it is very prob- able that I can help you. Write TODAY. CLARENCE A. O’BRIEN, Registered Patent Attorney, Washington, D. C. 345 Security Savings & Com’! Bank Bldg., directly across street from U. S. Patent Office. oo wee eee wee eee ee ee ee oe CLARENCE A. O'BRIEN, Resistered Patent Attorney, Washin 345 Security Savings & Com’! Bank ‘on, D. C. Idg., directly across street from U.S. Patent Office. Please send me your free booklet ‘‘ How to Obtain a Patent”’ and blank form ‘‘Record of Invention’’ without any obligation on my part. (Write clearly) | See top of page eight in front of book for details s e 8 r Radio Phone Receiving for everybody. Written in non-technical terms by nine specialists. pages. Fully illustrated. Price $1.50. Pooular Science Monthly, 225 W. 39th St., New York PATENTS | TRADE-MARKS, COPYRIGHTS AND PATENT LITIGATION Write for advice and instruc- tions how to proceed, costs, etc. ‘ Hand Book with illustrations of 100 Mechanical] Movements sent free on request. ALBERT E. DIETERICH Patent Lawyer and Solicitor Successor to Fred G. Dieterich & Co. 60 Ouray Bidg. WASHINGTON, D. C. PATENTS BOOKLET FREE HIGHEST REFERENCES PROMPTNESS ASSURE! BEST RESULTS Send drawing or model for examination and report as to patentability WATSON E. COLEMAN, Patent Lawyer 624 F Street N. W., Washington, D. C. SECURE A PATENT, Methods, etc. certbocoeresemecvae seve tgeeaneaseeesv.e coos ecee eo ee 60 8 eee eee eee eee eee eee PATE NTS TO GET A PATENT, sent free on request. Send model or sketch and description of your inven- —_—_ ae eee eee eee = =» tion and we will give our opinion IF YOU HAVE AN } INVENTION and DESIRE TO LEARN HOW TO send for Our Guide Book, HOW Tells our Terms, HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY

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EARLE E. LIEDERMAN as he is today Call the Undertaker! What’s the use of living when you're only half alive? You get up in the morning and you don’t have the pep of a jelly fish. Your work is a burden and life has ceased to give you a thrill. You don’t seem to get anywhere and nobody cares whether you do or not. What’ s the use, fellows? Call the Undertaker, for you're dead and you don’t know it. A New Life Stop! It’s all wrong. There is another life right here before you. A mew and a better one. A life that is full of thrills and sun- shine. Every day opens new worlds to con- quer, new joys, new friends and lasting ones. Come with me and let me guide you toit. I have a system that knocks those gloom bugs higher than a kite. I’ll put pep in your old backbone that will make you feel like a jack rabbit. I'll put a spring to your step and a flash to your eye so that your own friends won't know you. Health and Strength That's what you need and that’s what you get. ome on now, pull in your belt and throw out your chest. Take a good deep breath of that pure air that’s all about you. Give yom heart a treat with some rich blood. You will feel so good you think it’s your birthday. "Drop me a line and I'll show you how to doit. I’m going to put a chest on you that will make your old ribs strain with the pressure. I’m going to change those skinny arms and legs of yours to a real man’s size. You will have the strength and vitality to do things ‘ou never thought possible. Come on, fellows! — usy. I don’t promise — things—I them. Are you with me? Send for My New 64-Page Book “MUSCULAR DEVELOPMENT’”’ It contains forty-three full page photographs of myself and some of the many prize winning pupils I have trained. Some of these came to me as piti- ful weaklings, imploring me to help them. Look them over now and you l marvel at their pres- ent physiques. This book will prove an impetus and a real a to you. It will thrill you through and through. All I ask is ten cents to cover the cost of wrapping and mailing and it is yours to keep. This will not obligate you at all, but for the sake of your future health and happi- ness, do not put it off. d today—right now, before you turn this page. EARLE E.LIEDERMAN Dept. 1312, 305 Broadway, New York EARLE E. LIEDERMAN Dept. 1312, 305 Broadway, New York City The Shipshape Home How to Do the Odd Jobs No HOME work- bench or tool cab- inet is complete without a number of files of different sizes and shapes. For an all-around set of files for the home, I should suggest the follow- ing: 10-in. flat wood file 10-in. half-round wood file 10-in. hand file, second cut 10-in. hand file, smooth 6-in. hand file, smooth 8-in. pillar file, second cut 10-in. half-round, second cut 6-in. half-round, second cut 6-in. round, second cut 6-in. handsaw file, double cut, second cut. This set with handles would cost, I estimate, about $7. It goes without say- ing that it is economy to pick out the best files that can be obtained. A dollar or two more doesn’t count in this case, as poor files will not last very long. The files listed will cover almost any job the home Files and Filing worker will be called on to do, whether re- pairs, making new articles, or sharpening garden and other tools. In use a file should always be kept bit- ing; that is, cutting. If the file is allowed to slide half-heartedly over the work, it soon becomes dulled or shiny. On wrought iron or soft steel greater pressure is re- quired to prevent it from glazing or slip- ping than on cast iron or steel. To file a narrow surface straight re- quires considerable practice. When the file begins its stroke, the downward pres- sure exerted by the left hand holding the outer end should be at its maximum, while a minimum pressure is given by the right hand, which holds the handle. As the file advances, the pressure from the left hand decreases, while that of the other hand in- creases. After considerable practice, one is able to regulate the pressure on each end of the file unconsciously, so that any “rocking” motion of the file is prevented. Amateur mechanics sometimes find confusing the various names used in e— : iH i @ i te tA ay ) wy, ss 3 WY. ea Ui ME gi °).wyse ! / . Cs x ‘iy ‘li fe 5} - Vulcan Rubber Cemented Shaving Brushes True friends of shavers and razors. Easy shaves and smooth skins, Bris hair and handles never part com. eld with pure rubber vulcanizedashardas granite. pa ny eater meng Lo a singly in packages. Infe cannot come from — Send for Illustrated Literature John L. Whiting-J. J. Adams Co. Bosten, U.S.A. BrushManufacturere for Over! 14 93 Years and the Largest in the World YOU CAN PLAY THESE IMMEDIATELY! A Remarkable Bargain for Lovers of Music Here’s your chance to own a musical instrument you can really play. Ne Mecossary; an can SEND NO MONEY —merely your name the an on - Plays real music in and receiv: clear, mellow esl atthet sue OF th 3 by Lp be sent with allCanadian fo: eign orders. Combination Offer $6.61 for both. of Uku- andolins, > Vi THE dein STUDIOS 212 Fifth Avenue, New York fireproof = re silient A composition material easily applied in plastic form over practically any kind of floor. Laid about % inch thick. Imperial Floor does not {7 crack, peel or come loose from foundation. A 7% continuous, fine grained, smooth, non-slipping [7 surface. No crevices to gather grease, dirt, dust, [7 disease germs or moisture. ye Ideal Floor for Kitchen, Pantry, Bath Room, 7% Laundry, Porch, Garage, Restaurant, Theater, Hotel, Factory, Office Building, Railroad Station’ Hospital—wherever a beautiful, substantial floor 7 is desired. veral practical colors. Full in- formation and sample FREE of your first and second choice of color. Imperial Floor Co., 166-168 Halstead St., Rochester, N.Y. A Success for 15 Years HAIR GROWS! Dear es i seer Secession 10 ae. for which describing files. Terms such as “mill,” When our Vacuum Cap is used a oO oO sen t part wh atever, a copy of your Iatest book, “i Muse “flat,” and “half-round,” refer to the few minutes daily. Sent on 60 days’ cular Development.” (Please write or print plainly) shape or style, that is, the cross section. FREE trial at our expense. Stops Sie The cut is referred to by two sets of terms. falling hair and dandruff. Science aaah ae aris One refers to the character of the teeth, combined with common sense. No ‘ aes 9p te > drugs or electricity. A postal brings pore’ which may be “single cut,” ‘double cut, illustrated booklet. ait “rasp cut.” “i CORT ES bene ee a a (Continued on page 135) Modern Vacuum Cap Co. 400 Barclay Denver, Colo, es sah gh RR en 136 URIs cy 8 ai a RD ERR CREO ECE POPULAR SCIENCE MONTHLY | TI “coa “smi coar: roug and and roug roug ye et = Od Od

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d d ir 1° © Be d n HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY 135. The Shipshape Home — e (Continued from page I34) The other designations are for the de- gree of coarseness of the teeth—“rough,”’ “coarse,” “bastard,” “second cut,” “smooth,” and “dead smooth.” The coarse and bastard cuts are used .upon rough and heavy work; the second cuts and smooth cuts are used for finer work and for finishing work that has been roughed down by coarser files. The very rough and dead smooth are seldom used. A file that has one of its edges or sides smooth is called a “‘safe edge file” and is used in filing in corners where only one side of the corner is being worked. Files are cutting tools. They should never be thrown into a drawer or be allowed to come in contact with each other or any hardened metal. Keep them in a rack at the back of the bench, each in its own hole, or in a shallow drawer, separated from each other by partitions. Buy your handles when you buy the files and get good ones. Bore a small hole in each handle to a depth equal to the length of the tang; then counterbore this hole halfway in with a drill or bit of a diameter equal to the thickness of the tang about three quarters up from its point. Drive in the file tang by means of a block of wood held on the file end and struck with a hammer. Never strike a file with anything hard if you value your face. When buying files and handles, get what is called a “‘file card,” a sort of brush with stiff wire bristles, used for cleaning the files. Don’t allow your files to rust or rub together. Files are the most abused tools in the world and yet among the most use- ful. You can’t get along without files, and they cost money, so take good care of them.—HENRY S. LARABY. Wuen a window- Fi Ixing Shade shade roller refuses Rollers to hold, dust some talcum powderon the “live” end roller, as shown, and work it under and around the latches. Tal- cum powder or or- dinary toilet pow- der is made from soapstone and is a dry lubricant. It is advisable not to use oil, which will collect dust and in time make matters worse.— E. W. CORNELL, Adrian, Mich. : In REMovING old Removing varnish from floors Varnish and other woodwork with varnish re- mover, the work may be speeded up and lightened by using an ordinary squeegee, such as is used by window washers, instead of steel wool or ascraper. If the varnish remover is applied generously, almost all of the old varnish may be removed in this way by going over the floor once. The squeegee is used as in cleaning a window. | wn 10 GCraatact Invantarc PATENTS Seventy-six Years of Practice HE firm of Munn & Company filed its first application for a patent in 1846, and for seventy-six years has endeavored to keep pace with the inventive genius of the United States. An experience of many years is at your disposal. If you have an invention which you wish to patent, send your sketches or model together with a description of your device, explaining its operation, and you will receive prompt, courteous attention. Write for our Handbook on PATENTS A full and complete booklet on Patents, Designs, Trade-.. Marks, Foreign Patents, Copyrights, Labels and Patent Office Practice with an explanation about our methods, terms, etc. All communications strictly confidential Keepin touch with the inventions of the world by reading SCIENTIFIC AMERICAN : The MONTHLY MAGAZINE with a special appeal to every man of inventive genius. Recent rulings of the Patent Office, descriptions of the latest patented inven- tions, legislation and court decisions affecting patents, are noted in this authoritative publication. MUNN & COMPANY Patent Attorneys 683 Woolworth Building, New York City Scientific American Bldg., Room 3, 625 F Street, Washington, D. C. 801-D, Tower Building, Chicago, Ill. 602 Hobart Bldg., San Francisco, Cal. J have averaged °7000 Per Year for Three Years—Have Made Over $90 PROFIT in One Day’’ That is the statement of Frank DePries, one of our live-wire resentatives. Keeton of M ppi made $252 on first sale. Vickers of Alabama made wae ee mee wei Conant quit a $6,000 job to ‘We have a plan to work and ambitious to make some real money, our whereby our You need no experience, as we train you without cost for work. No pn pe can get a great capital required. tod territory going fast. Better write us at once. addition to their THE FYR-FYTER COMPANY the pla —autokt 1714 Fyr-Fyter Bldg. Dayton, Ohio POPULAR SCIENCE MONTHLY 137 — Se eee aoa a eet oe ——=y |

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URDOCK. HEADPHONES $420

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MULTIPLE PHONE PLUG JACK (Cord Tip Type) Enables you to have 4 pair of headphones connected at once. GET ONE. AT ALL DEALERS WM. J. MURDOCK CO. 345 Washington Ave., Chelsea, Mass. Sales Offices, Chicago and San Franci A New MURDOCK Product ]

Warren Radio Loop, Cut Away to Show Construction, RADIO

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Is There a Polar Paradise? (Continued from page 31) It is no speculation of wild improbabil- | ity to picture a polar paradise like some | titan emerald in its alabaster setting. At Disco, Greenland, orchids warmed by natural hot springs blossom out of doors | through the bitter sunless winter months! Weighing carefully all the facts avail- able, we may set the area of the new land at about 50,000 square miles, or roughly the size of the state of Pennsylvania. Its perimeter is bulwarked by a quake-dis- |) torted range of mountains buried in eter- nal ice and snow, and rearing 10,000 feet into the sky. Twisting fiords penetrate |! the ragged ice-gnarled coast. Just inside the mountains hangs a veil of fog, the vapor of contrasting tempera- tures. For here we may imagine the as- pect changes sharply. Heat from a nether world defies the cold. White of snow and ice shades swiftly to the green of verdant pastures, and gold of wooded uplands. We come upon a level clearing on which are spread symmetrically half a hundred human habitations. Tall men magnifi- cently built and clad in short and bright- hued loosely fitting blouses are moving leisurely about. Mingling with them are comely, fair-haired women in dainty smocks. Laughing children dash here and there among the shrubbery. No savages are these descendants of the vanished colony. Indeed, we shall be mistaken if they are not far in advance of our own smug selves in culture, learn- ing, deportment, and social refinement. They have harnessed natural energy to an amazing’ degree. They know the truths of other worlds. They have mastered the secrets of health. May Revolutionize Commerce Yet we need not be swept away by too sanguine a view of what the ZR-1 may find. There are other features savoring more of cold, hard facts than of romance. For instance, a polar air route cuts the distance to European and Asiatic capitals from 11,000 to 5000 miles. A vast volume of commerce and traffic will be deflected from America toward the Pole. No matter what the land may be which lies close to the Pole, it will control the Polar Ocean strategically. Appreciation of this fact is evidenced by Amundsen’s an- nouncement that his next great effort to be first across will include three planes. And there are whispers that two other powers are grooming entries for the race. Alaska then must come into her own. She will gather population and stand as an arctic service station to passing planes. The ZR-1 may get away by early June. The weather then is calm; the daily tem- perature just above the freezing point. After her 6000-mile flight from Lakehurst to Point Barrow, from which she will eventually take off, there must be a period of final grooming; possibly a trial or two out over the icefields. And by the Fourth of July, 1924, we should know the answer to this most, thrilling of all man’s geo- graphical conundrums: Does a polar paradise exist? And, if so, are the vanished Norsemen there?

mAnTT sam COIBRAIS'CD ANAT LOST YV

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»babil- | > some | ig. At | ed by | doors | onths! avail- w land ughly ee ce-dis- |. 1 eter- | 0 feet etrate & veil apera- he as- nether w and rdant which ndred agnifi- right- oving m are lainty ‘e and of the ill be vance learn- ment. ry to y the have y too may oring ance. ts the pitals lume ected which 1 the ion of ‘Ss an- rt to lanes. other race. own. nd as ssing June. tem- oint. hurst will eriod r two ourth uswer geo- af so, Edison, the creator; The 10 Greatest Inventors (Continued from page 37) In the amazing development of uses for electricity, two names stand out among a score of modern miracle workers. They are Thomas A. Edison and Nikola Tesla— Tesla, the man of visions. Nearly a thousand patents have been credited to Edison. But the single inven- tion of the incandescent light would have entitled him to a place on the roll of the famous, for he has illuminated the world with a lamp that rivals sunshine in bril- liancy and that is safe and convenient. This same invention paved the way for the vacuum bulb and long-distance radio. Like Bessemer, Edison started on a career of research and’ discovery during boyhood. For rescuing the little son of a station agent from an oncoming train he was taught telegraphy by the grateful father. His first patent in 1868, when he had just passed his twenty-first birthday, was for a mechanical vote recorder. Two years later, drifting into New York City without a penny, he invented the stock ticker that he sold for $40,000. With this fund he set up a little shop of his own at Newark, N. J., where he produced the quadruplex telegraph, saving millions of dollars in constructing telegraph lines. But it was in his laboratory at Menlo Park, N. J., established in 1876, that Edi- son gave to the world his most useful dis- coveries. Here he produced the first phonograph, and here in 1879 he placed his first incandescent light in a circuit and burned it for 40 hours. Three years later, at the age of 35, he put into operation the world’s first life-size experimental electric railroad. Edison has entered every place where men work and has lightened labor and made life more worth while. Edison’s Most Useful Discoveries -Following Edison and carrying forward his work of harnessing electricity for the uses of mankind, comes his friend and admirer, Nikola Tesla. In the discovery of alternating current power transmission, Tesla has carried to. our very doors the energy of nature, split up into fractions of horsepower or grouped in thousands of horsepower, and distrib- uted almost without loss. Tesla, standing at the turning point from the past to the future, has announced definitely that power soon will be transferred by wireless for commercial uses, lighting homes and driving airplanes; that wireless lights will be as common on the farms as ordinary electric lights now are in our cities. He asserts that even now he is ready to transmit 1000 horsepower without wires with a loss of not more than five per cent in transmission, and he assures us that the day is not far off when we shall be able to go anywhere in the world—to the moun- tain top, to the Arctic, or to the desert— and set up a little wireless equipment that will give us heat to cook with and light to read by. Born in what formerly was Austria- Hungary, Tesla from early youth was moved by the desire to harness the forces of nature for the service of mankind. It (Turn to page 138) POPULAR SCIENCE MONTHLY if THERE ft TSALL RIGHT ya Now! + 35A—104D "GLa Mb iia IT RECHARGES YouR BATTERY OVER NIGHT” | wiTH YOUR OWN § ELECTRIC CURRENT Full radio tones will not come from “empty” radio batteries Even the finest radio instrument will not give results unless the battery is doing its full duty. For complete and satisfying reception from near and far, no other combination equals the reliable storage battery and the Tungar for keeping it tuned up. With Tungar in the house you are prepared for perfect reception always, without having to move the battery aninch. You renew again and again with Tungar and your regular elec- tric light current. Tungar attaches wherever there is a lamp socket or a convenience outlet. Just turn it on and leave it, any time, day or night. Its cost of operation is low. There are no mov- ing parts to get out of order. ' For years motor car owners have used Tun- gar for charging their automobile batteries. See one at any good electrical shop, or write for literature. Address Section P 12. Merchandise Department General Electric Company Bridgeport, Connecticut Tungar Battery Charger. Oper- ates on Alternating Current. ; (Prices east of the Rockies) 2 Ampere Outfits Complete— $18.00 5 Ampere Complet $28.00 Special attachment for charging 12 or 24 cell" B” Storage Battery—$3.00 Special attachment for charging 2 or 4.volt “A” Storage Battery—$1.25 Both attachments fit either Tungar POPULAR SCIENCE MONTHLY The very things you need. Latest styles. Factory -to- Family prices. Save big money. Furnish a room or whole home. Aslittle as $3 down; a year or moreto pay. Also Pianos, Players, Phonographs. Cut out this adv.—write TODAY, for new “Larkin Book of Better Homes”’, ne oe" Our No. 12 Automobile Set box contains 6 camp Sas the 8S. A. E. thread, rhs Special 5 Size Tap and Die Set, Only $3.00 premarin emebes ns urnished in our ed dies (4, B16, UAL Eg "), ‘= oe ee Send us yout order a ese tnd bu oe of wt satisfied customers send you one of our circulars oor full ce WORCESTER STEEL PRODUCTS og Dept, M. 29 Union Street, Worcester, Mass., U. S, A.

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BOXING, Jiu-Jitsu, OWN rice again. Now you can get D the areas Marshall Stillman Course for $1.97. It teaches you how to feint, duck, block and hit like a professional. It con- tains all the secrets of the ring. A pugilist says: “Your course is a most valuable assis- tant to any cne whowishes to become either a real prize fighter or an amateur boxer.” All that is needed to master the Marshall Stillman rse is persistence. Every movement is described so clearly you have no difficulty in understanding it. You are taught expert blows such as Corbett’s Left Hook; Fitzsimmon’s Shift; the McCoy Corkscrew; the Demp- sey Triple. Jiu-Jitsu and Wrestling are also included. You are taught bone-breaking holds, how to take a gun, club or dagger from a ruffian and break his arm, how to render an opponent helpless, break a grip on your throat, or baffle a man who tries to kick you. A 96-page book containing the lives of famous pugilists with many little known stories is included FREE. . =e POPULAR SCIENCE MONTHLY SEND NO MONEY Fill out coupon and we will send you course. Hand the postman a temporary deposit of $.97 and send us the re- maining $1.09 in 10 days if satisfied. Otherwise return the course and we will return your deposit. MARSHALL STILLMAN ASSOCIATION Dept. 1123-M, 42nd St. and Madison Ave., New York You may send me on approval the Marshall Stillman Course. I will deposit 97 cents (plus actual postage) with the postman, with the understanding that if, after 10 days, I wish to return the course, I may do so and my money will be instantly refunded. If I keep the course I am simply to send you $1 in final payment. Canadian and foreign orders must be accompanied by cash ($1.97 U. S. funds) subject to money back guarantee if not entirely satisfactory. ZF ‘Pred genuine UNDERWOOD inder- " m ayments, or if convenient, pay cash. way you get the wo ds standard typewriter at a big cash saving. WHY PAY RENTAL? Be a 8 rs e offer same three models of the Underwood P ee -Emporium IPMAN-WARD MFG. 2149 Shipman Sid¢., CHICAGO by return mail Bargain Offer No. 2149 a Standard Visible Writing Underwood. is is — an order and does not obligate y. Poh Zz : ee Be Sie Te ew ish et EP 8 ¢ ° v sn | a g 0 yj -) Fy Ps | 140 The Practical Gift Projects a_ better, wy clearer, more direct light exactly where you need it—in home, office, store, studio, workshop, laboratory. Adjusto- Reg. U. S. Pat. Off. Solid brass; a quality product through. out. -Clamp is felt-lined. Can't scratch, 5 year guarantee. Sold by all live dealers, If your dealer cannot supply you, order direct, : S. W. FARBER, 141-151 S. Fifth Street, Brooklyn, N. Y. Prices in U.S. end Canadi, bi . i enamel finish, $5.50. West of Mineiisign! iver tae Eien Fou, Too, Can Piszy the geome HAWAIIAN. GUITAR. Just as the, After Your 2ST LESSON You Will Pl«: “ALOHA”. We Guarantee That— ina’ the natives do! Only Four Motions— and Ne Master Them Quickly 1 ecanattor that g short period of practice and you withave mustered this w: Hpowest mask. Com lcte course of 52 lessons includes FLEB waiian Guitar, necessary picks, steel bar, etc. Noextras. No Previous Musical Knowledge Neces never read note in your life--if haven't lar this wonderful! you test knowledge of music can the even the can quickly and positively teach you ar ngtrament: Bon'tbe just a listen Hawatian Guitar The 10 Greatest Inventors (Continued from page 137) was soon after he had come to America in 1888 that through a large electrical con- cern he was able to manufacture his induc- tion motor and to introduce on a large scale his. system of alternating-current transmission, which since has _ been adopted universally. His single achievement in the long- distance transmission of power places him definitely among the greatest inventors the world has known. In the last few months man’s mastery of the air has been demonstrated dramat- ically by a non-stop airplane flight across the United States, by the successful in- auguration of transcontinental air mail, by the trial flight of the dirigible ZR-1, and by the amazing speed records of more than four miles a minute. These achievements are reasons enough for adding Wilbur Wright to the list of the immortals of invention. By his im- agination, by sheer daring, and by patient and undiscouraged experiment, Wright has opened the limitless sky to our use. The flying machine had its beginnings in a simple toy—a device of cork and bamboo driven by rubber bands—that was given to Wilbur and Orville Wright by their father. They called it a bat. Failing to build a bat that would fly, they turned their attention to kites. The flying machine was the ultimate result. While the brothers worked jointly, it is to Wilbur, the elder of the two, that we must give chief credit for the airplane. Because of his work, today such wonders as wireless control of pilotless airplanes are in sight. Other Names Worthy of Honor It would be unjust to be silent concern- ing James Watt and the steam engine, or Marconi and wireless telegraphy, even though I do not include them in the list of the 10 greatest. Marconi hardly can be called an originator, since he adapted and applied the discoveries of the great Hertz, and since Preece, an Englishman, demon- strated a low-frequency system of wireless communication before him. Likewise, Gutenberg, the accredited father of print- ing, was foreshadowed in China centuries before. Fulton, Franklin, Westinghouse, Mergenthaler, De Forest, Stevens and the screw propellor; Hyatt, the discoverer of celluloid; Otto, the developer of the gas engine; Lake and Holland, creators of the modern submarine; Allen A. Canton, who has succeeded in deriving power from disintegrating atoms into electrons—none will deny the right of these to a place among the immortals. Yet, although they cannot be called imitators, they are not strictly originators. The inventions for which they are famous do not possess the epoch-making, widespread utility that marked the work of the 10 whom I have called the greatest. With all these achievements we have only scratched the surface. Far greater inventions than the imagination can pic- ture are on the horizon. For every new discovery, for every problem that is solved, a host 6f others await to be grasped by the inventive mind of man. POPULAR SCIENCE MONTHLY —T— ee ee, hhlCUC*” ae 5

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.in on- uc- rge ent pen ng- im ors ery at- in- ail, R-1, of ugh > of im- ent ght ngs and hat ight bat. hey The it is we une. Jers ines ern- , Or ven list n be and rtz, 10n- less vise, ‘int- ries use, and erer gas s of ton, rom 1one lace ugh are ions ility m I 1ave ater pic- new t is » be n. Here Are Correct Answers to Questions on Page 46 1. Scientists believe that the tiny one- celled animalcules that live in ponds and ditch waters are plant-animal creatures that lived on earth before the animal and plant stem of evolution became divided, 2. The wireless waves are ether waves. They pass through water, earth, and all other kinds of matter in much the same way as they do through air. Wireless sig- nals will pe down through water and can be picked up by apparatus inside the sub- marine just as if it were on the surface. 3. Soap contains a material that has the ability to stick very tightly to things. It creeps over their surfaces as a film of oil will creep over the surface of water. When you wash your hands, a very thin film of this material creeps all over your hands next to the skin. It even creepsin under- neath any particles of dirt that happen to be sticking to your skin. It pushes these loose and the water washes them away. 4. The earth is shrinking slowly and this puts a good deal of strain on the surface rocks, especially in parts of ‘the earth where the rocks are being forced up into the mountain wrinkles. Sometimes a few layers of the rock break under this strain and the rocks on one side of the break slip up or down or sidewise. The shock of this slip makes an earthquake. 5. No. It used to be believed that certain foods, especially fish:and other foods con- taining phosphorus, were especially valu- able for the gray matter of:the brain. This is not believed any more. Brain cells apparently use the same kinds of food ma- terials as all other living cells do. The best way to feed your brain well is to keep your body in good health. 6. Because of the currents in the ocean. Off the coast of Maine there is a cold cur- rent coming from the polar regions and flowing southward. It cools the air and makes the climate colder. Off the coast of France there is a warm current—the Gulf Stream. This gives a warmer climate. 7. Because the bird is touching only one wire. No electric circuit is completed. 8. No. If anything, they are more healthy. Prehistoric skeletons, as well as the mum- mies of ancient Egyptians, show they suffered from many of our diseases. 9. We are not sure, but it is probable that they migrated from- Asia across the Behring Straits thousands of years ago. The easternmost point of Asia was prob- ably connected then with Alaska by a land bridge that since has been submerged. 10. Food keeps on cooking as long as it is hot. The fireless cooker merely keeps it hot by preventing the loss of heat. 11. Many of the little nerve fibers in the brain that connect one brain cell with an- other get disconnected temporarily so that the messages between the cells cannot move about as freely as when we are awake. Some stop altogether. Others continue to move in a rather uncertain way, and this is what causes dreams. 12. There is no exact limit. It depends on the way the current passes through the body, on how long it lasts, on the general health, and so on. coe mere | there is no danger from the usual house light circuits of 100 to 120 volts. POPULAR SCIENCE MONTHLY POPULAR SCIENCE MONTHLY a aes ees ees ee «ee: es ee | es sees 3 ees ee ae + ee + ce «eee «eee + eee + Sens Sees seme seers ceeee eee ee an ae ep sabre sabi, comes cae Teaser team Aw iEMC THE CHEMICAL OUTFIT HALUETA THEE LAREN Vhitj pueetniie? io vsae a gana 44 lggaana ane pesaoere! MUNIN OO TESS TURTLES { # hee ee. eo =. ees ee MITTIN EO MLL EEO CE COO OOOO CC STC Boy Chemist! ANY boy can be an amateur chemist and perform hundreds of in- teresting chemical experiments, just like a real chemist. You can test the things you eat, wear and use every day; make ink, soap, dyes and many other useful things, and get reliable and practical knowledge of the most absorbing science there is today—the Science of Chemistry. You can also do lots of wonderful chemical tricks that will puzzle all your friends, Select from These Chemical experimenting is the most fascinating thing you _ever Five Dandy Outfits did; there is always something new : and different to do every day. 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Without cost or obligation on my part, please ‘ell me how I can qualify for the position or in the subject before which I have marked an X: BUSINESS TRAINING COURSES Business Management Salesmanship Industrial Management Advertising Personnel Organization Better Letters Traffic Management Show Card Lettering Business Law € Banking and Banking Law Business English Accountancy (including C.P.A.) 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Send for catalog illustrating Oxo-Gas appliances for all purposes where coal is used. We have openings for General Sales Managers and distributors. Only those who can finance themselves considered. GLORIA LIGHT COMPANY 108 N. MAY ST. CHICAGO, ILL. Evolution—A Universal Law (Continued from page 57) Science itself, being merely a tissue of known facts and accepted ideas, is sub- ject to evolution. In primitive medicine, for example, it was customary to cut a hole into the skull in order to relieve head- ache. The idea, one imagines, was to let out some spirit or other evil creature who was believed to be producing the pain. These ideas have evolved. We think differently nowadays about the cause of headache and we treat it, we feel sure, more successfully. Yet it is probable that the physicians of a few thousand years from now will look back on the medical theories and practices of 1923 with the same curious pity that we feel for the savage surgeons who cut into living skulls to let the demons out. But the evolution of ideas and of cus- toms, like that of human inventions, be- longs really to the evolution of life. The body of man has evolved and his mind with it. To prove that evolution is a universal law we must produce evidence more fundamental than this. We must show that evolution applies to non-living matter as well as to living matter. Can this be done? Evolution Applies to the Stars It can. One of the greatest achieve- ments of modern science is that it has been able to prove'within the past 20 years that evolution applies not only to life and to all products of life, but also to things as life- less and as fundamental as the stars and the chemical elements. If you take a telescope and go off ad- venturing with the astronomers into the depths of space, you will find that all the stars you can see are great suns like our own sun, many of them, in fact, much larger and hotter and mightier even thaa it is. All these star-suns belong, the as- tronomers find, to a single series, like the children of one family. But the family of stars has one great difference from a family of children. The youngest stars are not the smallest ones, but the largest. The baby stars, born only a few billion years ago, are tremendously big. The old, old stars, millions and mil- lions of years old, are small and shrunken and nearly dead. What happens to the family of stars, the astronomers believe, is about like this: The first stage of a star, so far as we now know, is probably what is called a dark nebula. This is merely a vast cloud of very thin gas or dust spread about in a certain part of space. It sends out no light, so it looks dark. Gradually this cloud draws itself together into a more or less globe-shaped mass. As it does so, it becomes hot. It begins to shine. It en- ters the first visible stage of a star, a baby star in years, but a giant star in size. One of the stars that is in this stage is the great red star called Betelgeuse that forms the shoulder of the hunter in the constellation of Orion. The size of this star was measured recently by the astron- omers at the Mount Wilson Observatory, and it was found to be so vast that if it took the place of our sun, the entire orbit (Turn to page 141) Not toys—but high “grade practical instruments for orchestras. pare or Jazz Greatfor solo work at ge ov Legion gatherings or home entertain- we Anyone can play with a few simple lessons, fa-aiehed with eae a genes? Mando-uitierp’'* ‘usical'saw Wolner'tes® Tela Fe ceistihes, you can’t lary ¢ Free Trial et tee teeters atom om , BY sac MUSSEHL © WESTPHAL JAMONDS Guararilée a a a oo 8 Featieen INN boy ire Pal 21 Jewels, A: SS em 4 “FATHER ealtions, Gad Alle be 21 Towel, ‘Aiiosted a LOFTIS BROS. & CO. National Jewelers iT eal 108 N. State S au. tores in Leading Cities nesceaaes Ww. F. YOUNG, Inc. 350 Lyman Street Springfield, Mass, INettelaolhal- te THE ANTISEPTIC LINIMENT AGENTS: 56 iii Ss o.8 sf } me eo K OD aes Oe A MHyQ_O eB a> om a hUrltlCU

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Evolution—A Universal Law (Continued from page 140) of the earth would lie inside it. Yet the matter of the star is very thin. It is a bubble of highly rarefied gas rather than a solid ball like the earth, or a globe of dense gas, almost liquid-like, such as we believe our sun to be. What will happen to this young giant star as it grows older we cafi foresee, we believe, from the present condition of other stars. It will grow smaller and denser and at the same time hotter. After a while it will be a brilliant white star like the dog-star Sirius. Though it will continue to shrink, it will stop grow- ing hot. Instead, it will cool off a little and its light will become more and more yellow. Presently it will resemble our sun, which is a star past the first vigor of youth and well along in middle age. Finally, as it cools off more and more, Betelgeuse will become still smaller, more and more red- dish in color, less and less brilliant, more and more dense. In the end it will be alto- gether dark and probably solid. Every Star Is Changing Every one of the thousands of stars that you see in the sky and each of the millions more that the astronomers have counted on their telescopic photographs is believed to represent a definite stage in this development from a dark gas cloud. There are many details of this evolution that we still do not know. But of the fact that stars change there can be no question at all. : And with the chemical elements the proof is just as sure. A distinguished and sincere opponent of the theory of human evolution, Mr. William Jennings Bryan, has argued that if evolution be true of life, it ought to be true of everything, and that since (as he believes) it is not true of the chemical elements it cannot be con- sidered true of life. It is unnecessary to pause over the weak logic of this argument—the obvious pos- sibility that evolution might be true of life and still not be applicable to every- thing. The evolutionist need not quibble. He can accept the argument on Mr. Bryan’s own ground. If the theory of evolution is to stand or fall, as Mr. Bryan argues that it must, on the question of its applicability to the chemical elements, it will stand and Mr. Bryan should accept it. For the chemical elements do evolve and science has proved that they do. The outstanding example of this chem- ical evolution is the element radium. The peculiar properties of this element—its continual emission of heat, the rays from it that affect a photographic plate, its ability to make the air about it a conduc- tor of electricity, its curative properties in disease—all are due to the fact that the atoms of radium are in evolution. Radium belongs, in fact, to a series of no less than 27 chemical elements that make up a known evolutionary series. The first one, the original parent element (so far as we now know) of the entire series, is uranium. Uranium changes after a while into another element called Uranium X, this into a third and so on for four changes. The fifth element is radium. (Continued on page 142)

POPULAR SCIENCE MONTHLY 141

OU want to make more money. You want to do the work you like. You hope to be in- dependent, to be your own boss. Perhaps you want to travel and see the world. Vou want to get out of the rut. You want a job witha real future. Then learn about the opportunities that exist everywhere, at home, in your own town, on rural routes, state highways, cities, etc., offering every choice of climate and living con- ditions, of starting your own business, asa garage or tire service shop. Auto mechanics are needed everywhere, and men who want to travel and see the world but don’t want the responsibility of owning their own place find jobs at $50 a week and up quicker than any other line of work. Over sixty thousand men have proved this to be true, and over twenty thousand are running their own business. These are the interesting figures from the records of the world’s greatest and most successful trade school, the Million Dollar Sweeney Auto School at Kansas City. How to Be Sure of a Steady Job I am teaching the most practical, most profit- able, easiest learned trade in the world. I am teaching white-collar boys from cities who want to get into overalls, and boys from the farm who want the bigger opportunities and advantages of city life. I am teaching coal miners, factory em- ployees, unskilled laborers of all kinds, men who want to quit being wage slaves whose job a strike or bad business or employer’s whim can termi- nate without warning. Who want a chance to be independent, make real money, and own their own business. I refer you to sixty thousand men who found the way to success by sending for my catalog. The Sweeney trained men are ready to HOLD GOOD PERMANENT JOBS. To be partner or owner in a garage. To be independent. To be in business for himself. He is not working in a factory that may close down overnight, on a railroad where a strike may put him out of business, in a coal mine where labor troubles may send him to the bread line. He has CAPITAL in his head and hands. Be Your Own Boss Of the 60,000 Sweeney Graduates I estimate that 20,000 of them own garages, tire shops, vulcanizing and service shops. It is easy to start in business for yourself. Then you don’t have to bow down to some employer and do work you don’t like. I say work for yourself, then you are not bothered by strikes and lockouts or factories closing down. OWN YOUR OWN BUSINESS. Work for yourself with enthusiasm, not drudg- ery. It’s the yearning of every young man to BE HIS OWN BOSS, and Sweeney makes it possible. Sweeney trains men in eight weeks in the Auto and Tractor business, and you don’t need pre- vious experience. The man who writes for my CATALOG has taken the first step towards his OWN BUSINESS, Towards independence and prosperity. It’s just your own lack of energy and enterprise that’s holding you back! Trust yourself. I will show you HOW EASY it is to be a man of standing and importance in your town. A Billion Dollar Business The AUTOMOBILE BUSINESS is America’s greatest industry. It em- st twice the capital of the National anks in the United States. In 1922 peo- ple paid ONE BILLION, FOUR HUN- DRED AND NINETY MILLION DOL- LARS FOR TIRES, and over SEVEN HUNDRED MILLION DOLLARS for partsandaccessories. Yet this great business is just beginning. In ten years there will be over 23 million pleasure cars alone, That is about one for every family. Trained mech- anicsareindemand. Hundreds of thousands of them are needed not only as mechanics but as salesmen, garage owners, tire repairers, dealers, demonstrators, chauffeurs, etc. — The smart man will QUIT his job and iearn

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DEAD Tt we. bo Send me YOUN Presse Gusiness- the Auto a SURE TRADE. He will BUILD A BUSINESS OF HIS OWN. He will be independent and not at the mercy of strikes, depressions, and circum- stances beyond his control. : There was never a time when a man should con- sider his future and plan to put himself on a sure foundation more opportune than TODAY, Don’t be a wage slave! _ In thousands of localities there are opportuni- ties for garages, repair shops, tire shops, sales agencies. Radio offers similar independent oppor- tunities. Own your own shop. Stand on your own feet! How can you get into this great business? What Others Have Done There are opportunities everywhere, Other fellows with money are often looking for trained men to handle the mechanical end as partners. Look at Clayton Eden’s nice garage at. Ains- worth, La. Clayton says: ‘“‘We operate the leading garage, Have all the business we can do. Also handle Hudson, Essex and Buick cars. Owe my present success to the wonderful training received at the Sweeney School.” Roy A. Atkinson sent me this letter from Everett, Mo. ‘‘Worked on a farm,” says Roy. ‘‘At:nineteen had only $14.00. Got father to send me to the Sweeney School. Three days after I came home I fixed a neigh- bor’s Ford car. That was my start. Today this garage is worth $4,785.00. My business takes three men to handle. I never worked in any other garage. I used m Sweeney training. If you want to get that start, do as did and go to the Sweeney School.” Look at John Boyer’s garage at Milford, Ill. John ay ‘‘Having a good business; busy eff the time.” an far off Australia S. A. Noller writes business is What these boys have done YOU can do. If xou like mechanics, write me today for m big free Catalog. Mail the coupon today or post will do. What Is the Sweeney System? The oe | System is the practical way—the only way to learn if you want to get into the Automobile business at the least possible expense of time and money. It is easy—requires no previous education—no books —only ei he weeks’ work. Our way of training is in- teresting in the extreme because it is so praci'‘l; no esswork toit. Just like a boy told me this ino: ning. e said: ‘‘I really ought to go home and help ti.< old man with his crop, but I never had so much fun ai worked as hard and learned more in my life.’ he couid spend six months here and every day learn something new. Get this Free Catalog If interested in betteri: your condition, imply send name today and get a free copy of my new - trated 64-page cataloz and a free copy of the interesting Sweeney News; also many pictures sho men at work and play in this world-famous school. I will also tell you about a special new offer I am making, and some interesting opportun- ities in this line of work. ere is no cost, no obligation, no one will call on you, or bother you. Nocolored students accepted. Just send name today to E, 3: oeoumey, President, SWEENEY AUTO AN peatinly | ang? sgumaaae °. Dept. 1258, Kansas City, ane sem gue OL en ae Sweeney, SWEENEY. Chyy, MO ust in oney ss ynities EN: Mresjigotion of one CR TALO Gl

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Evolution—A Universal Law. | (Continued from page 141) | Then when radium changes, it produces a’ || gaseous element called niton. This, too, evolves and changes into another element, a solid one this time, and so on until we reach an element which, if it changes at all, does so so slowly that we have not yet proved the change. This final element is lead. No one believes, however, that lead is really final or unchanging. It merely changes so slowly that we have been un- able, as yet, to detect the change. We already have, indeed,some evidence that it does change. Not only lead but all other chemical elements have been found to possess in a very slight degree the same properties that make radium so remark- able. Radium produces much heat, but all kinds of 1aatter produce a little heat. Radium gives out powerful rays, but all kinds of matter give out feeble rays of the ; same kind. It is probable, therefore, that A MONUMENT TO all kinds of matter are undergoing evolu- SCIENTIFIC RESEARCH es tion, though an evolution much slower CUNNINGHAM VACUUM TUBES, built by one of the world’s than the change of radium. largest manufacturers with unlimited resources, are the product ¥ of years of research and development work by that great scientific organization, the Research Laboratory of the General Electric a 2 Benjamin F; ranklin’s I nsect Story ompany. ro The development of the special filament used in the two new Cunningham Tubes, type C-301-A, and C-299, is truly a monument In an often quoted letter of Benjamin to the scientific skill of that organization and the ability of its Franklin he speaks of those insects that engineers. . " . ay : > ame ey ay , Senture of ate Semone. is its pypperty x* Aish stectoan — . live only for an hour or two in the summer emission at a low tempcrature. i ts i i S i i i greatly increased output, with only a fraction of the filament power esa and he imagines one of these to. he casey sumed by previous types. ing to its companions the appearance of Patent Notice: Cunningham 14 Ampere Filament Current. the world. The flower on which all of ered by patents, dated 11:7-05, 1-15-07, Mutual Conductance 700 Micronzhos. them lived was, quite evidently, eternal. Licensed for amateur, experimental and Through the length of a long life, urged entertainment use in radio communica- tion. Any other use will be an infringe- CUNNINGHAM RADIO TUBES the oldest of the insects, the flower had not C-301A— 6 volts } amp. Amplifier been observed to change. There were, ment. 5 C-299—3 volts .06 amp. Dry Battery De 5 Fy and Am 6.50 moreover, ancient traditions that through ° C-300—6 Volts Gas Content Detector... 5. ° ° ° fe C-11—1.1 Volts .25 =<} D many generations of previous insects i Det. and Amp. Speci

dep ae heey wail Mii cia aeatten ee gin cial Base 6. C-12—Similar to C-11 with standard base 6. _— _— been i“ anny cape ant we é such a thing as change be thought of in ee ee es gg feng ee oy ‘ mane York City NY. this pleasant perfumed plain? : Now we, who feel sometimes that we live so long and so importantly, have but little longer tenure of this pleasant earth SCETRTITE Hotel of ours than had the tiny insect of his = ae Position flower. Things that seem to us unchang- (4 , ve, Waiting ing may be no more so, in reality, than isa AUK,

ee i“ - re flower, if only we grant time enough for be them to change. Evolution is not a rapid ——- 7 process as men count time. It has re- quired long and able investigation, the accumulation and study of innumerable facts, in order to discern it atall. — But this is not because evolution is con- own , cealed. It is because man lives for such a Living Exp enses Paid little while. Even the whole billion years There’s an enviable, pleasant, big-paying posi- of earth history into which ‘we have tion waiting for YOU in one of America’s fine | | Crowded the origin and evolution of life is hotels. Wonderful opportunities. for advance- but a moment in comparison with the ment to executive positions. vastness of time. . You Can Qualify THE END (either man or woman) for one of the many positions to be filled by our graduates. Meals and often rooms provided; chances to save unex- FOR FURTHER READING celled. Previous experience unnecessary. » N THE evolution of the chemical elements Take the First Step Now see “Within the Atom,” by John Mills, (D. van _ Get particulars regarding the Hotel Opera- Nostrand Company, New York, 1922). The tion and Management Course prepared by ex- conclusion that all kinds of matter are slightly perts, giving you practical hotel training in a few radioactive rests, in the main, upon experiments by weeks’ spare time. When you graduate we will Prof. R. A. Millikan announced in several scientific gladly put you in touch aap ulna fain in ean ga lectures but not yet published in full. I know of no with hotels now asking for Standard Business comprehensive and non-technical book in English S. B. T. I. graduates. TP oe y= on the evolution of the stars. An excellent brief Write for Bulletin of J gina me oo ne account is “The New Heavens,” by Dr. George positions open. Mail the I firing fall information about Ellery Hale, probably the most distinguished living coupon NOW. otel tion and Manage- | astronomer. It is published by Charles Scribner's By ploy- | Sons, New York, 1922. A good short article on STANDARD BUSINESS ; stellar evolution, by Isabel M. Lewis, was pub- TRAINING INSTITUTE yg Name----------- v---» | lished in the Scéenttfic.American for July, 1923. Carlton Court, Buffalo, N.Y, # Street ae!

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COS emperature Control crisp, evenly colored crackers that are now to be had in every food store in any part of the country aren’t the result of chance. They are made by the millions—yet whenever y you buy them, whether in North Dakota or in New SIX SENSES i Mexico, Connecticut or California you know they ‘ ne will be of the same dependable quality. V7 a Sti n g Be In the old days no two crackers tasted exactly Mm rib- alike. They were made by bakers who depended on S eein g ‘ their sense of taste. Naturally they varied in taste . —and quality. Fee li n g nak Today the sense of taste in manufacturing has ‘ , “ d been replaced by the sixth sense of industry —Tycos. Tycos in the Home Hea ri ng not Certain temperatures, exactly regulated and ac- ie a curately controlled, are required in making crackers Tyeos Office Thermometers S m ell ing ’ —and all other food products that are baked, boiled, An aid | in promoting hu- ugh roasted or otherwise cooked before they reach the icioahane aed a nd on cts public. Drcos Bath Thermometers ul d ‘ ‘ ; : To enable you to get the Ty co Ss in This exact regulating and control of heat required See ee oe 'y in baking is supplied by Tycos Instruments. ; g is supplied by Ty Sine minn se Temperature we These instruments are more than human—they Bake Oven Thermometer. but work automatically —there is no guesswork in man- See ete Th ete Control. th ufacturing when they are used. Tycos Instruments of accurate results ‘in re ensure the uniform quality that is essential to any esa his product that has a big sales volume. Tyeos Wait Thermometers * Se a ees se acc ian Forecasts the weather for MANUF ACTURERS Ke , twenty-four hours ahead fycos Quality Compasses with .dependable accu- pid What is your problem of applying the “sixth cake ssekunblen a roe re- sense’? to your manufacturing? For every process ain Feos Hyerometer the requiring heat control or regulating—in any in- Fycos Fever Thermometers a ee oe bee ble dustry —there is a type and style of instrument in Oe aaa in every monphhere i your home the Tycos Line that embraces over eight thousand 4 3 on- varieties of heat control, indicating and recording Your dealer will show them to you. Ask us, on a ha instruments. postal, for booklets on any of the above. ars Write us and informative literature on any in- % ave strument or type of instrument will be sent prompt- TYCOS and the MEDICAL Profession eis ra ly. Or, if you prefer, our experts will advise you on Jos Sphygmomanameter, Pocket and Office type the how money can be saved in your plant by the appli- Zeos Urinalysis Glassware. Zeos Fever Thermometers. Bulletins on request. cation of Tycos Heat Control. Canadian Plant TYCOS BUILDING Taylor /nstrument Companies : Main Office and Factory TORONTO ran | | ROCHESTER, N. ¥., U.S. A. CANAD

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yh. A | ‘ ligt Be Fay. ue . i A SS oe r ; % ‘ | 7 : + wi wis a @ 7 ‘ | } : | bo i9 4 f ei ——- - y, oy : ae a . é ae f & y, + ye, _ 7 wy) Q\ xy —— \ fi } bat 3 fi \ e % ; % cf, (Pt 4 Now is the time to select your Victrola for Christmas Victrola Instruments and Victor Records are so much in demand for gifts that there is a shortage every Christmas. Place your order now while all the twenty-one instrument styles at from $25 up and complete record stocks are available. Ask your dealer or write to us for illustrated catalogs. ~wictrola His SusTeNs vores” * Look under the lid and on the labels for these Victor trade-marks Victor Talking Machine Company, Camden,N.J._

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