Popular Science Monthly 1925-01: Vol 106 Iss 1

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Prd POPULAR SCIENCE MONTHLY SUMNER N. BLOSSOM, Editor January, 1925 George Eastman—Greatest Amateur Photographer The remarkable story of an idea worth millions—How a young bank clerk took the mystery out of a magic art and put cameras in the hands of every one—What we may expect from photography in the future BOUT 47 years ago, a young man of 24 became seized with an idea regarding a hobby to which he had been devoting all his spare time. By day this young man was book- keeper in a savings-bank in Rochester, N. Y. By night and on his holidays he was a scientific experimenter, al- though he would scarcely have ap- plied that name to himself. His hobby was photography, which at that time, in 1878, offered fewer inducements by far to a young amateur investi gator than avia~ tion, say, does now. In fact, it may be said there were almost no amateur photographers in those days. Pho- tography was a deep mystery to the ordinary per- son, a sort of black magic. Taking a single picture was very often a day’s By Raymond J. Brown loading of the camera had to be per- formed in darkness, it was necessary that he carry a lightproof tent or shelter whenever he ventured to take landscapes or other outdoor photographs. A heavy view camera, an awkward Taking a Picture in the Olden Days—A Silhouette tripod, quantities of chemicals and a bucket of water were added details that made the luggage of the photographer of 1878 about equal in weight and bulk to the camping gear of the well-equipped automobile tourist of today. Now, the idéa that the young man in Rochester conceived about all this was that the photographic proc- ess was needlessly complicated. He knew the pleasure that he had derived from pursuit of his hobby; he assumed that others would find equal pleasure in it if only the tedious, almost overwhelming dif- ficulties of its prac- tice could be eliminated. And since no one else appeared eager to simplify photog- raphy, he decided to attempt the thing himself. So he hired a little room over a shop and began to ex- work, and required such fine skill and expert knowledge One of the first attempts to make a photograph, in the early eighteenth century. The subjett to be ‘“‘photographed”’ sat between the source of on a board. , His shadow blocked off a certain proportion of the light rays, and as a result his profile in silhouette was left on the paper. periment. The results of and such elaborate, costly and cum- light and a sheet of sensitized paper fastened This image, however, faded in a few minutes those early experi- ments you see everywhere about bersome equipment, that the few who had mastered the art were glad to capitalize their knowledge by util- izing it professionally. The photographer, for example, had to be a practical chemist, capable of taking a sheet of glass and several bottles of chemicals and manufactur- ing a “‘plate’”’ on the spot by the com- plicated wet-collodion process each time he wished to take a picture. Since this work and the subsequent How I Use My Copy of PopuLar ScIENCE MONTHLY LIST of the names of the prize-winners in the contest announced in our October issue will be found on page 4 of this issue. you. They supply one of the most thrilling romances of modern busi- ness, one of the most inspiring chron- icles of scientific achievement of all time. For within two years the young man in Rochester was manu- facturing one of the best of the early dry plates that eliminated much of the unwieldy equipment of the photographer. Within five years he had paved the way for the motion picture and for 33 if

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34 the enormous present-day popularity of amateur photography by the substitution for the glass plate of a roll film of paper. Within 10 years he had produced a camera with which the novice, aon his first attempt, could take good pictures simply by pointing the camera at his. subject and pressing a button. Moreover, he had added a new word to the language— “kodak,” which he coined himself and First Folding Kodak Produced in 1892, it made a four-by-five picture, and was heavy and cumbersome compared with the trim’kodaks of today which you’ll now find defined in any dictionary as “‘a portable camera for taking instantaneous photographs” —an honor which rarely if ever has been accorded to the copyrighted trade name for a commercial ar- ticle. Within 11 years he had made commercially practicable the pres- ent cellulose film. Within 13 years he offered a camera that could be loaded in daylight. Within 20 years it is safe to say that there was searcely a person in the civilized world who had not made “snap- shots” or been the subject for **snapshooting.” Today it is virtually impossible for anybody anywhere to pursue his daily activities without en- countering in one form or another some of the far-reaching develop- ments that can be traced directly to the experiments that the young man in Rochester instituted in his laboratory almost a half century ago. You can’t walk through the streets of the smallest village or the greatest ‘city, go on a rail- road journey, automobile tour, or boat trip, take a Sunday afternoon walk or a summer vacation with- out encountering kodaks. If you don’t see them in use, you see them displayed in an amazing variety of stores, or you see kodak pictures in your home, or in your office or shop. There are upward of 200 illustrations in this magazine, and a goodly portion of them are reproductions of kodak pictures made by amateur photographers. Probably you own a kodak yourself; if not, it is likely that some member of your family does; certainly you would find it difficult to name three families of your acquaintance in which there is not at least one. When you go to the movies, the pic- tures you see are direct results of that POPULAR SCIENCE MONTHLY young man’s experiments of 47 years ago, for he made possible the photographic film, and now makes practically all the motion-picture film used in America. That you can see your way to your seat in a motion-picture theater now, instead of stumbling around in the dark as you used to do, is due to the fact that methods of showing pictures in lighted theaters were devised in his laboratories. You can thank him, too, in large measure for the excellent clearness of the movies you see today, for it was scientists in his employ who taught the theater owners the proper kind of screen to use to ob- tain the best values in pro- jection. Results both direct and in- direct of those early experi- ments likewise are felt today in dozens of fields only re- motely connected with pho- tography—in industry, medi- cine, and diverse branches of scien- tific research. De- % The First Real Portrait Ever Taken Above is a reproduction of the earliest sunlight picture of ahuman face. It is a daguerreotype of*Miss Dorothy Catherine Draper, and was taken by her brother, Prof. John William Draper, M.D., LL.D., of the University of the City of New York, early in 1840. The subject had to sit motionless in bright sunlight for about six minutes, in strik- ing contrast with the instantaneous photography that is possible today velopments springing from those experiments were of signal use, too, in the late war—in the per- fection of naval camouflage, in aerial photography, in the train- ing of airplane gunners. In fact, the ramifications and by- products of those attempts 47 years ago to simplify the making of photographs are so amazingly complex and extend in so many different directions that merely to catalogue them probably would take as much space as this entire article. You may have noticed that I have not yet mentioned the name of the man of January, 1925 whom I write. Probably I might refrain from doing so entirely without fear any one’s failing to know exactly whom } mean, for the development of no other art, science, or industry probably is gg inseparably linked with the name of one man as is the development of photography, particularly as it affects the amateur, with the name of George Eastman. And yet it is surprising to what a limited degree any knowledge of this man, be- yond the fact, of course, that he is at’ the head of one of the world’s great com- mercial enterprises, has traveled beyond his home city of Rochester. ()TRER great inventors, other great industrial leaders, other great philan- thropists—and George Eastman is all of these—are known widely, quoted widely, pictured widely. But the personality of George Eastman has remained screened behind the results of his labors—a fact that becomes the more astonishing when you meet him, for he is an affable, color- ful, buoyant, amazingly youthful man whose enthusiasm for the accomplish- ments of the enormous plants and the vast army of workers that are now the Eastman Kodak Com- pany is as lively as was his interest: in his own experiments when he to make the practice of his hobby. easier for himself and others. There was a vibrant ring in his voice and a glitter of pride in his keen eyes as he showed me, in his office in Rochester the other day, the latest triumph of his great fac- tories—the ciné-kodak, a compact, entirely foolproof motion-picture camera for amateurs, the operation of which is so simple that it makes tuning a one-tube radio receiver seem like a scientific achievement by comparison. Nor do I make that assertion by hearsay. Though I would not call myself even an amateur photographer, I went out and made pictures with the camera—good pictures—and pro- jected them on the screen a few hours later with the projecting machine that is part of the outfit. There is a reason why Mr. East- man should be especially interested in this machine. For him it links the The Father of the ‘‘Brownie’’ The original Eastman kodak of 1888— father of the present-day ‘‘Brownie,’”’ which it resembles. Compared with the pocket folding kodaks of today, it is somewhat crude and clumsy; yet compared with the cumbersome equipment that confronted the amateur prior to its appearance, it was a . marvelous achievement of inventive genius was just a young bank clerk trying janua

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POPULAR SCIENCE MONTHLY Eastman at His Hobby—Taking a Picture with His New Amateur Movie Camera This is one of the few photographs for which George Eastman has posed. It was taken especially for Popular Science Monthly in the garden of his home in Rochester, N. Y., and shows him operating the latest triumph of his great factories—a compact, foolproof motion-picture camera for amateurs. This little machine, representing five years of research, he says, has at last fulfilled the dream of ‘‘movies in the home.”” In the 47 years since the time when, as a young bank clerk, he began experimenting with cameras, Mr. Eastman has revolutionized photography and has estab- lished one of the most remarkable industrial enterprises in the world; yet he still classes himself as ‘‘an amateur photographer.” Today, at the age of 70, he retains the enthusiasm of the amateur and the keen interest in scientific progress that have marked his achievements, and that have built up his wonderful organization. “I often buy Popular Science Monthly,” Mr. Eastman told the author of this article. “I want to keep informed on new developments in science and mechanics, and Popular Science Monthly enables me to do so in an easy and interesting way” present with the past; it does for motion pictures exactly what he did for still pictures when he produced the first kodak in 1888—so simplifies their making that the veriest novice can take good pictures from the start. “This little machine,” said Mr. East- man, “‘represents five solid years of re- search. People have been talking for several years about ‘movies in the home’ as an interesting possibility of the future. Now that the ciné-kodak is here, the future has arrived in that respect. Any- body who can read a set of simple in- structions can make perfect motion pictures with this machine; can make them, too, at one-fifth what it costs for the mere developing and printing of an equivalent length of standard film. “ HEN we first made kodaks, we had a slogan, ‘You press the button; we do the rest.” We might well revive that for these machines, for we are equipping some of them with electric motors to turn the film, which makes pressing a button all the operator need do. We develop the film without cost. We don’t print it, for that has been made unnecessary by an ingenious process re- cently developed in our research labora- tory whereby a negative film can be reversed and turned into a positive ready for projection. “Tt is this that has made possible the ciné-kodak for home use. Without this process, the cost of making motion pictures undoubtedly would be pro- hibitive for the ordinary amateur. Now, though, any one can chronicle the de- velopment of his children, record his vacations, picturize any event he may wish in motion pictures that he can see in his own living-room whenever he (Continued on page 141)

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36 POPULAR SCIENCE MONTHLY January, 1925 When Men Race with Death to Make the Air Safe The story of a hazardous sport that has joined hands with science in amazing tests of speed and skill—How a plane is launched from an airship—Amateur flights point the way to a new day of safe, practical, and cheap air flivvers In an instant, a dot high up against the heavens becomes a glistening pair of wings, shooting down at the ground, almost straight, at incredible speed. No one knows how fast; some say 300 miles an A TINY speck grows in the sky. By Peter Vischer hooked under the car of an army dirigible, was released and took the air. The same dive, the same straightening out and the same soaring away into the distance marked this feat, so graphically shown on the cover of this magazine. promise for the success of commercial aviation. They can visualize ‘‘ feeder” lines for cross-country dirigible liners. A dirigible going from New York to Chicago, for instance, could take passen- gers for intermediate points and could set them aground with- hour; some say 450. No one knows. Just before the ground is_ reached, when it seems as though this whizzing streak must be crashed to earth be- fore your eyes, it straightens out and with a thrilling and awe-inspiring grace speeds off into the distance, far and away. That’s airplane racing. A hazardous sport, you say. Hazardous, yes; no man is so fearless of death, so utterly contemptible of death, as is the airplane racer. A sport? Yes and no. HE men who race in airplanes don’t consider racing a sport. They look upon it as scientific research. Speed, speed, and more speed. It is abso- lutely necessary, they believe, for the proper development of aero- nautics, not half so much for the hanging up of new records as for the study of strains and stresses. Through the ap- parently reckless stunts of racing, pilots and designers learn how airplanes may be expected to act under all circum- stances. Consider again the swishing dive of the air racers. The spectators at the recent International Air Races at Wilbur Wright Field, Dayton, Ohio, were thrilled when a small messenger plane, City of Skyscrapers Attacked from the Air The destruction of a model City of New York in 30 minutes by air raiders was the startling spectacle that closed the recent International Air Races at Dayton, Ohio. This illustration shows the aerial bombs bursting among the Not only can an airplane be started from a dirigible, but it can return to its perch by means of an automatic attaching device. Future-looking aeronautical en- gineers see in this new development great city’s skyscrapers, and in the air the exploding shells from anti-aircraft guns. was staged as a demonstration of the deadly effectiveness of aircraft as weapons of modern warfare, and imagination supplies its horrors out delaying the straightaway flight of the mother ship. In the same manner new passengers could be taken aboard. Maneuvering mes- senger planes to and from dirigibles, how- ever, takes more than ordinary skill. Here again racing proves its value. It teaches pilots how to handle their machines under the most trying cir- cumstances. S° THE people who go to air- plane races — and some 50,000 went to the recent meet in Dayton — may look upon racing as a sport, but racers don’t. They look upon racing as a serious occupation, so necessary that life is not too much to risk for it. And once in a while a life has to be given. At the Day- ton meet, Capt. Burt E. Skeel, as fine a pilot as the U. S. Army had in _ its ranks, gave his life to racing. Captain Skeel was diving for the start- ing line in the Pulit- zer Race, the world’s premier event for air- plane races, when he met death. His plane, a Curtiss R-6 racer, one of the fastest machines in the world, was dropping out of a leaden west, diving for the starting pylon, going at a speed greater than any that ever had been recorded. Suddenly, as his plane was The spectacle

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1925 rcial der” ners. k to ssen- id set with- the rht of . In r new d be mes- >» and how- than Here roves aches andle under y cir- ople air- - and nt to et in look as a racers look as a on, So life is 0 risk in a to be Day- Burt ine a iS. : > Sts s life 1 was start- Pulit- orld’s or air- en he plane, racer, vorld, living speed been was . have been most gratifying. January, 1925 POPULAR SCIENCE MONTHLY 37 A Parachute Jump Above: One of the many thrill- ing sights of the Dayton Air Races—a para- chute jump from one of a number of planes in flying formation. The parachute can be seen in the distance, at the lower center of the photograph, with two planes hovering on either side of it dashing toward the ground, it was seen liter- ally to fall apart. A wing dropped off, and flut- tered to the ground like a piece of paper. The entire fuselage of his plane burst into fragments. The en- gine, and with it the courageous Skeel, plunged toward earth, landed in a swamp, and buried itself feet deep, throwing huge clods of earth for hundreds of feet. Curiously enough, despite the tremendous hazards of speed racing == = = : Plane Launched from Airship At left: A small army messenger plane hooked under the car of the U. S. Army dirigiiie TC-5, ready to take the air. This was one of the amazing feats per- formed at the Day- ton races. Not only can a plane be launched from an airship, but it can return to its perch by means of an auto- matic attachment protected and do not suffer at high speeds. There is a limit beyond which no man will be able to go, of course; but: just what that limit is, nobody knows. One of the most daring of all the speed pilots is Lieut. Russell L. Maughan, a one- time Pulitzer Race winner. He takes corners within 20 feet of the ground, often within six feet, with his plane in airplanes, Skeel’s death was the first fatality in a Pulitzer Race. The results, on the other hand, Americans hold the world’s speed record as a re- sult of the Pulitzer Races, a record established in 1923 by Lieut. A. J. Williams of the U.S. Navy, known to thousands as ‘‘Al’’ ever since he pitched baseball for the New York Giants. Williams went at the rate of 243.67 miles an hour, a mark no European machine has been able to approach. HERE wasn’t a chance of beating Williams’ mark in the 1924 race, be- cause there was no new machine in the race. Lieutenant H. H. Mills of the army won in a Verville-Sperry racer, a mono- plane that looks like a darning-needle, but he couldn’t make it go any faster than 216.55 miles an hour, which is almost 380 miles slower than the record of Lieutenant Williams. Airplane designers are satisfied that the speed limit by no means has been reached. Captain Skeel before his death said he was certain that 300 miles an hour on the straightaway would be done within a very few years. He said that a machine able to go 265 miles an hour already had been designed. A speed of 300 miles an hour on turns is a courageous thing even for a flier to predict. When a plane takes a corner at terrific speed, the centrifugal force draws the blood from the pilot’s head and into his feet. For a moment things go com- pletely black and a pilot is to all intents and purposes unconscious. Yet the pilots can do it if the planes can, aviators say. We are building our planes so well now that the pilots are well virtually vertical. He makes spectators gasp for breath. Yet he, too, believes that the speed limit by no means has been reached. HOSE who witnessed the recent inter- national air races may well appreci- ate what 265 miles an hour means. They saw Lieut. John A. Macready, crack American flyer, who participated in the non-stop transcontinental flight, go up in a Wright machine 20 years old, the second built by the famous brothers. It looked as though Macready was taking his life in his hands, the Wright machine was so frail. It seemed nothing but a bundle of bamboo sticks tied together with a bed-sheet. It went up so wabbly, faltering and wavering, until it looked as though any moment it would come down in a heap. But it didn’t. (Continued on page 144)

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An Air Hero—Hold How a Mechanic, N MOMENTS of extreme danger at sea and on land—when wrecks, col- lisions, or conflagrations have seemed imminent—there have been numbered countless heroes who have stuck to peril- ous posts to safeguard the lives of men and women intrusted to their charge. But few more daring or courageous than the young airplane mechanic who, to save his pilot and passengers from possible disaster, climbed out on the wing of a POPULAR SCIENCE MONTHLY ing the Brea Dangling from Wing, Saved His Plane giant Croydon-to-Paris passenger plane, and there held fast to a broken control for 40 minutes, until the plane landed. The great machine—one of those en- gaged in regular passenger service across the Channel—was flying high over the English countryside, when without warn- ing the control arm of the engine car- buretor broke, cutting off the gasoline. Instantly the mechanic crawled out on the lower wing of the plane in an attempt to repair the break. Finding this impos- sible, he decided the only thing to do was to hold the broken control. Thus, with one leg hooked about a strut of the plane, the other dangling over the edge of the wing, he hung on grimly minute after minute while the liner sped toward its airdrome. In the illustration above, our artist has thrillingly portrayed the reckless courage of this hero of the air. January, 1925 lon

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1925 ° OS- Vas ae] ing the has age January, 1925 POPULAR SCIENCE MONTHLY 39 A Thrilling Search for Wealth in the Wilds of Alaska Geologists Survey Resources of Oil and Metals in Far North By Norman C, McLoud from the wilderness of northern- most Alaska a little band of gov- ernment scientists after seven months of thrilling adventure and hopeless isolation in the heart of the frozen North. They had penetrated into the terrifying bleak- ness and desolation of the last remaining frontier of the American continent to measure its potential wealth—to survey the region for oil and precious and useful metals and to seek possible routes for transporting these valuable deposits to the doorway of civilization. The party was composed of geologists and topographers of the United States Geological Survey—four scientists and four assistants. Throughout their journey the treacherous hand of. danger con- stantly reached out to snatch them; and the least mischance might easily have brought serious consequences. Breaking ice blocked the river channels through which they traveled, and imperiled the frail sides of their canoes. The dogs that drew their supplies ate more than they , FEW weeks ago there emerged could haul in the sledges. Bitter cold— .- the kind that ‘‘runs out of the bottom of the thermometer’’—sapped their energies and gnawed at their morale. HEY set up their instruments and made their sketches with fingers that were stiffened and all but useless from the awful cold, with eyes blinded from the dazzling snows. For a period that most of us would have deemed intermin- able, they were marooned, with scant ra- tions and no avenue of escape, on a bleak island in the Arctic Ocean. For weeks their only fresh food was won by skilful marksmanship that brought down an occasional bighorn sheep. Their return to civilization was accom- plished only through a chance encounter with a government vessel cruising the Alaskan shores in search of shipwrecked sailors, after they had completed a 150- mile canoe trip through the icy, turbulent waters of the Arctic Ocean. In his steam-heated office in Washing- ton—a retreat that offered a startling contrast with the barren region he had just left—Dr. Philip S. Smith, leader of the ex- peaditi-on, sketched for me, a few days ago, a thrilling chron- icle of the ad- ventures of his party. Doctor Smith is a geologist, a stalwart giant, with a record of a dozen years or more in the Alaskan wilds. Second in command to him was Dr. J. B. Mertie, another six-footer of long experience in pursuing scientific in- vestigation under the most hazardous conditions. The other members of the party, too, were vigorous, outdoor men, chosen for this dangerous work because they possess the unusual combination of scientific knowledge and_ skill, with ability to cope with the ravages of Nature in her cruelest moods. The goal of the The Leader of the Expedition Dr. Philip S. Smith, geologist and stalwart giant, who led the government expedition into northernmost Alaska. He has spent a dozen years tramping Alaska’s wildernesses and ex- ploring uncharted rivers. He is in field togs explorers was the area known as Naval Petroleum Reserve No. 4, an area as large as the combined states of New Hampshire, Vermont, Massachusetts, Rhode Island, and Connecticut. Within the 35,000 square miles of this region pre- vious perfunctory surveys had shown un- mistakable evidence of oil and mineral wealth that invited American develop- ment, so the area was created a Naval Reserve last year and the Geological Sur- vey was directed to establish its possibili- ties. The region explored by Doctor Smith and his comrades stretches for 300 miles or more along the shores of the Arctic Ocean and extends southward into the lofty and rugged peaks of the Arctic Mountains. — expedition attacked its objective from the south, following a plan and an itinerary that Doctor Smith worked out a dozen years ago. Once they moved from Tanana, Alaska, from whence the start was made late last February, they were entirely “‘on their own.” They could hope for no help from those they had left behind; on their own careful preparations, their own vigilance, their own hardihood—often their own luck— the success of the expedition rested. “‘Our basic supplies had to be carried from the starting-point,’’ Doctor Smith told me. “‘It was essential that we should figure on complete independence. We hoped, of course, that we should find it possible to supplement our food supply by fishing and hunting, but we could not count upon it. We knew that we should see no human being from Tanana to Point Barrow, the northernmost tip of Alaska—a distance scarcely to be mea- sured in miles, but gaged by the time between March and September. “One item that will emphasize the re- quired attention to detail was the carrying of strips of wood for use in repairing our canoes in case of damage. We knew that much of the country we should traverse was practically woodless, and that if repair strips were wanted, they would be wanted mighty badly. Experience showed that we were right, and the strips saved the expedition more than once. “The supply train was a formidable procession, consist- ing of six teams of 15 dogs apiece, un- der the guidance of several whites and Indians. This train preceded the survey- ing party, which traveled with four addi- tional dog teams of similar size. ‘“‘The supply train carried three or four tons of supplies. In the selection of the outfit we were compelled to give careful consideration to what should be taken and what should be omitted. An outfit may easily become unwieldy. Take, for example, the item of food for the dogs. Each animal will eat two pounds a day. For 150 dogs this means a daily consump- tion of 300 pounds. A team of 15 dogs

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will haul from 1000 to 1500 pounds. This shows that the team will eat the equiva- lent of its load in from 33 to 50 days. te" ated ask me why we did not take more men, so that it would be un- necessary for us to work like stevedores. The answer is simple. Each man in- volves a burden of approximately 100 pounds in the items of clothing, bedding, cooking apparatus, and general outfit, to say nothing of three pounds of food for daily ration. Each additional man easily may become a factor of weakness.” The supply train started from Tanana about the middle of Febru- ary, followed a few days later by the outfit that a gentle sense of irony prompted the voy- agers to designate One of the government explorers standing beside a dog sled that carried supplies for the expedition into Alaskan wilds. Smoked glasses shield his eyes from the brilliant glare of the summer sun on the arctic snow as their arctic ‘‘ passenger train.” The freight crew had been carefully instructed in the mat- ter of the route to be followed and the system of leaving sup- plies along the journey for the passenger outfit. Under this well laid plan the advance party dropped a week’s supply of food at every six-day interval. The cache system worked with clocklike regularity. Wher- ever it was necessary for the freighters to double on their trail, leaving part of their burden for a second trip, cut branches of trees or shrubs furnished the basis and the covering for outdoor “‘ warehouses” which protected the supplies from predatory creatures. For the six-day intervals, however, it was deemed desirable to provide greater measure of precaution. The supplies for the passenger outfit were left suspended in trees after they. had been packed in small cloth sacks inclosed in water- proofed canvas bags. GOON after the surveying party over- took the freighters, it was found possi- ble to make the passage toward the north by proceeding up one of the tributaries of the Alatna River. This important dis- covery of a pass opened new possibilities for penetrating northern Alaska, and will doubtless play its part in future develop- ment of the isolated district. The pass penetrates the mountains at an elevation of more than 3000 feet, in the midst of peaks extending as high as from 6000 to 8000 feet. When it was determined that the freighting could be handled by the per- manent organization, the freight crew was dismissed and permitted to return to Tanana. At this point the expedition established

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veying. Old lines were picked up and the work was pushed into the Naval Reserve. The technical men carried on topographical surveying. The geologists conducted a study of the rocks, the measurement of sections, and kindred activities. In this work the members of the party traveled in groups, leaving the main camp for several days at a time. ‘At times the tem- perature was severe,” Doctor Smith told me.

its first base camp and began actual sur-

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The shaded portion of this map shows the loca- tion of United States Naval Petroleum Reserve No. 4—35,000 square miles of wilderness charted and explored for minerals and oil January, 1925 “To the geologists this was of little mo- ment, for they could keep moving. To the topographers, however, it was anothen. story. These men had to work in the open and each of them was compelled to occupy exposed positions from which he made his observations, the records of which had to be drafted with bare hands, “T HAVE seen the engineers draw con- scientiously for a few minutes at a time and then spend many minutes get- ting their fingers into condition to bend, Some of our trip was made in temper- atures colder than 50 degrees below zero, Until May first the night temperature’ was always below zero.” During the occu-; pancy of the first base camp, active operations were con- ducted for moving forward into the oil reserve before the melting of the snow should make it impossible to use the dog sleds for transportation. The men not actively engaged in surveys devoted themselves to transferring supplies across the snowfields into the Colville River region, north of the mountains, where a second base camp was established somewhat later. Late in May the snow rapidly disappeared, and by May 28 a small amount of water was run- ning by the camp. On the last day of the month, the expedition abandoned its winter camp and started downstream in boats. As canoeists the voyagers found their problems those of ice instead of snow. When the ice breaks in arctic streams, there is something appalling in the method of dissolution. The break comes with a mighty roar and rush. No sentry is needed to detect the opening of navi- gation, for the roar, Doctor Smith told me, is loud as summer thunder. Below: The rugged Arctic Range across the southern border of the Naval Petro- leum Reserve. The explorers found a pass through these grim mountains | gale navigation at the point of em- barkation offered problems of its own. For some distance the stream was extremely shallow and the men of the ex- pedition worked their passage even more vigorously than with the passenger train of the snows. There were many places at which the boats could not be floated, and the work of dragging the craft over ob- structive bars required that the voyagers wade constantly in icy waters. The ex- perience was one to make a lasting impression. ‘““We were successful in keeping our heads out of the water,” Doctor Smith told me; “‘ but at times that was about all.” Fifteen miles below the winter camp the voyagers reached open water. For the purpose of covering a greater survey- (Continued on page 145)

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', 1925 - € mo- 10ther. n the led to ich he ds of lands, V con- sata S get- bend, mper- ’ ZrO, rature® below occu-; first active: e con- loving he oil 2 the snow to use ation. ved in res to 3s the River tains, D was ipidly 28a $ run- e last dition p and their snow. eams, 1 the comes sentry navi- 1 told f em- f its n was he ex- more train ces at l, and or ob- yagers 1e ex- asting gy our Smith tall.” camp For irvey- January, 1925 POPULAR SCIENCE MONTHLY al Strange Jobs of Unusual People Here are six folks who never find their work monotonous s 4 Jay Bruce, offi- cial mountain- lion hunter for the State of Cal- ifornia. So far, he has bagged 206 lions, there- by saving thou- sands of deer and other game Straightening rifle barrels is the business of William H. Airs, of Whitneyville, Conn. He has straightened barrels for Roosevelt and “Buffalo Bill” Joseph Taylor, of Pipestone, Minn., is one of the few surviv- ing Indians who knows the art of cutting stone pipe from soft, red clay All through the winter, while storms are lashing Cape Cod, Therton Crowell & builds several thousands of them, and when spring ap- - proaches he paints them. sits in his little shop at Dennisport, Mass., and Mr. Crowell is shown above with a number of whittles out toy windmills. Every winter he his unusual windmill models that sell readily Teaching canary birds to sing by playing to them on a flute is one of the occupations of Mrs. Edward Smering, of Atlanta, Ga., who - conducts a bird hospital. Hun- dreds of birds are sent to her for treatment and training. She de- clares that the voices of the song- sters are improved by their trying to imitate the high flute notes A veritable Saint Patrick is James Morris Beck of Fredericksburg, Va., who makes his living by catch- ing snakes for circuses and museums. He has been in the business 28 years, and claims to have caught more snakes than any other man in Amer- ica. While he says he fears no living reptile, he has concocted a_ special remedy for snake bites

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POPULAR SCIENCE MONTHLY January, 1925 What Your Dreams Mean A noted authority explains the mystery of sleep—Why folks dream of falling from dizzy heights, of flying through the air, or wandering unclothed—How sleep fancies can be made to order—Unusual stories of the eight most familiar dreams By James J. Walsh, M.D., Ph.D. consulted me after dreaming that he had fallen 15 stories from the roof of a high office building. He had awakened just before he struck the ground. The man frequently dreamed of falling, it seemed, and he had heard it said that if ever one hit bottom in a falling dream, the shock would mean instant death. Was it true? Of course such an idea is ridiculous, but then, thousands of people believe that fairy tale. I should like to have reas- sured my patient with indisputable facts, but his question could be answered only with direct testimony. If any man has died from the shock of landing at the bottom of a dream precipice, he has not had the chance to tell us about it. My traveling man’s dream was easily explained. It was nature’s alarm clock to let him know that his legs were getting an insufficient supply of blood. He had eaten a heavy meal just before retiring, and the weight was pressing on the big artery over the spine, interfering slightly with the blood going to the limbs. This produced the same sensation experienced in descending in a fast elevator. Gravity being interfered with, he was catching up with the blood being pumped into his legs. The result was a feeling of being without foundation. A TRAVELING salesman recently ASKED him, too, about the condition of his bedsprings, for probably more than half of all falling dreams are incited by the dreamer turning over and sliding into a depression in the bed. Further, I learned that about a week previously, my patient had been watching a daredevil perform hair-raising stunts on the edge of the roof of a high office building. He had been deeply impressed by the danger of these spectacular feats. Then when. he experienced the falling sensation, the thoughts recently associated with it came readily in the form of a dream. Many persons are afraid of their dreams. Superstition has more power in this field than in almost any other. It is because human knowledge of dreams has come so slowly. For thousands of years scientists have been attempting to pry beneath the darkened glass that has ob- secured this mysterious function of the human mind, and even yet, they some- times have to answer, “I do not know.” In the last 20 years we have made more progress in understanding dreams than in many centuries before. We are at last seeing possible answers to the recurring questions of mankind: ‘“‘ What are dreams? What causes them? What do they mean?” ® Our most recent and significant experi- ments all point toward external causes for dreams. Thought processes, it is assumed, are going on all the time in our brains, at night, as well as during the day. The more complex functions, such as judgment and reasoning, ordinarily do not take place in sleep, allowing think- ing to take the form of loose associa- tions. Recently science has taken dreams into the laboratory in an attempt to analyze them and determine their causes. Experi- ments with drugs show a definite rela- tionship between external causes and dreams. They show definitely that dreams can be made to order. © seb physician gave a woman patient a grain a day of extract of the pitui- tary body to build up her blood pressure. After 10 days she began having very pleasant and satisfying dreams. Before, her dreams had been trivial, but now she began traveling to foreign lands, as she had always wanted to do. Everywhere she went, she saw beautiful landscapes in colors. When the treatment was altered and adrenalin, another gland extract, was substituted, at once a change came over the nature of her dreams. They lost their colors and became terrifying, filled with violent quarrels. Chemists and physicians know that in normal anger or fear the human body secretes adrenalin from the suprarenal glands. This sécre- tion makes our hair stand on end, a cold sweat appear, and the skin look like goose flesh. The experiment I have just mentioned showed that adren- alin treatments produced the same effect in the patient’s dreams. An overdose of insulin, the newly discovered gland secretion, was found to pro- duce the same feeling of fear. Maurey, a noted French psycholegist, first suggested that a physical cause was re- sponsible for dreams. He told of one of his own dreams as an example. Just before going to bed he had been reading about the horrors of the French Revolu- tion. When he fell asleep, he dreamed that he, too, was taken to the guillotine. His head was fitted on the block. Down came the gleaming, keen-edged knife, swiftly and more swiftly. Then, to his intense agony, it hit him and he woke in a cold sweat, to + find that a light curtain rod had fallen and struck him squarely across the neck. The falling rod did not just happen to hit him at the dramatic moment. The rod hit him first, he reasoned, and as this sensation penetrated his consciousness, the events about which he had been read- ing recently flashed into his mind. Thus it is that most, if not all, of our dreams can be traced to an external physical cause coupled with an association of ideas born of our waking experience. XAMINATION of thousands of dreams experienced by thousands of dreamers, has enabled us to learn that the most common dreams are eight in num- ber. And every one of these can be traced to some physical cause. The most common dream of all is said to be that of wandering about with in- sufficient clothing. In this, almost always the dreamer wakes to find that the bed-clothing has fallen from him, leaving some part of his body uncovered. Most of us have dreamed of running after something, a trolley-car, for example. After watching a daredevil perform hair- raising stunts high up on the cornice of a city skyscraper, a salesman acquaintance of Doctor Walsh dreamed he was falling 15 stories. In this remarkable article Doctor Walsh explains the association of ideas and the external physical causes that produced this terrifying dream that most of us have experienced either in one form or another Janu It is are ever you car | wak with agai A falli: is le by ° with sciol dow

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January, 1925. It is terrible; for in the dream your feet are fastened to the ground. Exerting every muscle and breathing as hard as you can, you make no progress. The car disappears in the distance. Then you wake, to find that your nose is stuffed up with cold and you are out of breath— again an actual physical sensation. | ging common dream is that of flying. Its cause is similar to that of falling. When you sleep, your diaphragm is less active and more breathing is done by the chest. Some slight interference with normal respiration causes con- sciousness of the chest moving up and down in quick, rhythmic movements. To POPULAR SCIENCE MONTHLY You have been lying in one position so long that the skin has become numb and no contact is felt with the bed. Feeling light and without contact with the earth, you dream of flying. Since the invention of airplanes, dreams of flying have increased. Our dreams may use any material stored up in our brains. All of us have many images of airplanes and other aircraft at call. With dirigibles now soaring over our heads, dreamers will add rides in airships to their list of interesting experiences. The dream of food, another common experience, usually can be traced to the sensation of hunger. I attach so much importance to this stimulus that when a man asks, ‘“‘Why do » I dream?” I often reply with the ques- tion, ‘‘When, or what did you eat?” Ernest Shackle- ton, the British ex- 43 plorer, has told me about many of his dreams in the South Polar regions— most of them about food, all of them due to acute hunger. Once, with two com- panions, he was separated from the rest of his party. Each of the half starved men had three large crackers a day. They ate these slowly, reaching out after every crumb. One night, then, Shackle- ton dreamed that he was at the Lord Mayor’s Banquet in London. All the viands for the entire meal were on the table at once, quite contrary to the usual custom. Shackleton was just ready to take the first mouthful, when he woke to find himself with a painfully empty stomach, on an iceberg in a frozen land. N OLD Persian legend tells of a man called Barmecide who used to torture victims, kept three days without food or water, by setting before them empty dishes and asking them to partake of the appetizing delicacies that he described. Most of those who “feast with the Bar- mecide”’ in their dreams could avoid this unpleasant experience by drinking a glass of warm milk before retiring. Dreams of murder and death usually are traceable to indigestion. A piece of cheese has been responsible for many a . nightmare. In such a dream one feels something seriously wrong, and in at- tempting to find an explanation for it, memory brings out from the storage house, the brain, the most terrifying images laid up there. So, too, any alter- ation of the blood supply to the teeth, or dental decay, may bring a dream that you are in the dentist’s chair. If, in early life, you have taken your school work seriously, you probably dream often of taking examinations. Men have told me that as much as 50 years after graduation, they have dreamed of examinations, and of being asked ques- tions they cannot answer. This often is caused by anxiety over the next day’s tasks. There is a sensation of unrest, and the dreamer, seeking some reason for it, associates it with an occasion when such uneasiness was felt—examination day at school. This type of dream is frequently experienced by doctors, law- yers, and other professional people who often are asked many questions. Ts amazing ability of the memory to produce long forgotten thoughts and images was vividly demonstrated in an experience of a friend of Samuel Butler, English novelist. This occurred in his waking hours, but it has particular bearing on dreams. The young man, 25 years old, tore the quick of his finger on a sliver. As he felt the pain, he remembered that he had had the same sensation at another time. It was when he was seven years old. He had poked his finger in a hole in the bed, in which a bolt had once fitted, and in doing this he had hurt his finger. He remembered that at the time he had picked up a piece of paper and had stuffed it in the hole. Then his thoughts started on a different channel. About that time a five-pound note had been lost in the house and never found. Suddenly now, 18 years later, there came the thought, ‘Perhaps that bit of paper I stuffed into the hole was the (Continued on page 150)

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] POPULAR SCIENCE MONTHLY January, 195 The Show of Your Lifetime To Be Seen during Total Eclipse of the Sun January 24 THIS PART OF SUN I$ OBSCURED fROM NEW ORLEANS BY MOONS- DISK MORE OR LESS EN- (PON, IN PARTIAL ZONES LIGHT SHADOW RING,OR PENUMBRA © of / | SUNS DISK DARK SHADOW ENTIRELY — RING,OR OBSCURED IN UMBRA TOTAL ZONE These diagrams explain what will happen during the total eclipse of the sun, January 24. Passing between sun and earth, the moon will cut off the sun’s rays. The small diagram immediately above shows how the sun’s face will appear in zones of total and also in zones of partial eclipse Rexnaaraticimees 4 ! *DULUTM ad a BUFFALO - TOTAL ECLIPSE. _ NEW ORLEANS - PARTIAL ECLIPSE; 67% NANT @QurrALo 67% PATH OF TOTALITY AVERAGES 100 MILES WIDE The illustration at the top shows the position of the moon between the sun and earth during the eclipse. At Buffalo, N. Y., where the ,axis of the moon’s shadow strikes the earth, the eclipse will be total; at New Orleans, 67 per cent. The path of total eclipse, as well as the percentage of eclipse in vari- ous sections of the eastern United States, is shown in the map at the left i By Henry M. Hall F, AT nine o’clock in the morning on I Saturday, January 24, you suddenly find the light so poor that you cannot read your newspaper or go on with your work, or whatever it may be that you are doing, don’t be alarmed or annoyed. Rather, consider yourself fortunate. Get out of doors as fast as you can, supplying yourself with tinted eyeglasses if you have them, and look up at the eastern sky. There, awaiting you, will be the greatest free show you probably ever will see—a total eclipse of the sun, a celestial phenomenon so infrequent that not one person in a thousand the world over sees one during a lifetime. Indeed, total eclipses of the sun are so very limited in geographical distribution over the earth that the coming one will be the first to be visible in the parts of the United States from which it may be ob- served since long before the days of electric lights and automoblies. HAT astronomers call the “path of totality’’—the places in which the sun will be entirely obscured—begins, for the coming eclipse, at sunrise in northern Minnesota, near the Canadian boundary, northwest of Duluth, with a width of about 84 miles. Sweeping south- eastward, with the staggering speed of about 30 miles a minute, this great celes- tial pencil mark will pass over Esca- naba, Mich.; Buffalo, Watkins, Bingham- ton and Poughkeepsie, N. Y., and New Eclipse Time-Table F YOU live in or near one of the representative cities listed below, cut out this time-table for reference on January 24. It will tell you the percentage of totality where you live, and the local time at which the mid-point of the eclipse occurs. The figures are from the U. S. Naval Observatory, Washington, D. C. Percentage of Local Place Magnitude Time New Haven, Conn. 100 9.20 Ithaca, N. Y. 100 9.04 Poughkeepsie, N. Y. 100 9.16 New York, N. Y. 100 9.15 Buffalo, N. Y. 100 8.51 Syracuse, N. Y. 99 9.07 Albany, N. Y. 99 9.18 Cambridge, Mass. a9 9.32 Philadelphia, Pa. 98 9.07 Cleveland, Ohio 97 8.37 Urbana, IIl. 91 8.02 Des Moines, Iowa 90 7.38 Topeka, Kan. 83 7.26 Atlanta, Ga. 80 8.12 Oklahoma City, Okla. 74 7.14 Jackson, Miss. 72 7.43 Austin, Tex. 61 7.07 Haven, Conn. The path gradually widens, reaching a breadth of about 115 miles at Poughkeepsie. HESE cities are all close to the center line of the shadowy ribbon. So, if you live within, say, from 30 to 40 miles north or south of a line drawn through them on the map, you can see the eclipse if you wish, and if the weather is clear. Sweeping across Connecticut, the path will pass over the Atlantic, maintaining the same general direction until it reaches about latitude 40° N., longitude 55° W., where it will attain its greatest width, and change to a northeasterly direction, sweeping up over the North Atlantic until it loses itself at sunset about halfway between Iceland and the Scandinavian peninsula. A word about eclipses in general; then let us picture what you will see if you are fortunate enough to be in the path of the coming eclipse. An eclipse is simply a more or less com- plete darkening of the face of the sun or of the moon. The first is caused by the passage of the moon between the sun and the earth; the second by the passing of the earth between the sun and the moon. Because the ever-changing relative posi- tions of the sun, moon, and earth recur in a strictly periodic or cyclical manner, the (Continued on page 146) Janu

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ary, 198 1e widens, niles at 2 center », if you s north hem on if you he path itaining reaches bB° W., ith, and rection, de until ialfway inavian l; then you are 1 of the ss com- sun or by the un and sing of » moon. e posi- ecur in er, the ienuary, 1925 POPULAR SCIENCE MONTHLY 45 These Boys Are Expert Mechanics Amazing Products Prove Youthful Skill in the Workshop | igAtabese3 before have children received such thorough training in mechanics as they do in the schools today. Almost by the time they are out of kindergarten they are learning how to use simple tools such as the fretsaw, and this education progresses through the higher grades. Yet the boys of today, not content with school training, are establishing their own workshops at home. Here they are doing amazing things in mechanical construction and invention, as shown by the pictures on this page. For example, there is Stanley Eintracht, a 17-year-old inventor of east London, England, who employs eight men in his own workshop. He is shown at the right with one of a his latest inventions—a radio set contained in a model of ah “Felix the Cat.”’ Another of his inven- tions is an ingenious ‘‘mother’s alarm’’ that will ring whenever the baby cries. At the age of 11, Kel- vin Vanderlip 2d, son of Frank A. Vanderlip, New York financier, is an expert in the use of carpenter tools, the lathe and circular saw. He is shown below ope- rating a bench saw At the left is a model town, com- plete even to tele- phone lines, built by Glenn MacEl- roy, age 12, in his back yard at Cin- cinnati, Ohio. He made the buildings all of cardboard The Good brothers of Los Angeles, Calif.,—Roscoe, age 19(right), and Wallace, age 17, have established a profitable businéss and national fame as builders of model ships STATA SATA eo ra Louis Cantenot of Dijon, France, is an expert astronomer at the age of 14. He has made many remarkable in- struments, including his _ telescope

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46 POPULAR SCIENCE MONTHLY Rear Motor Machines Designed to Split the Air “The cart before the horse’ well describes one of the most recent of European speed crea- tions (above). For in this car the power unit, including engine, clutch, gearbox, differ- ential and radiator, is located at the rear, while the seats for driver and mechani- cian are near the front, between the axle centers An Egyptian sportsman, Prince Djelaleddin, is making a bid for world speed records with the machine shown at the right. This car, designed by the prince, is driven by an eight-cylinder engine. Another new European racing model with power plant and radiator at the rear. This small, bullet-shaped car, of German make, is said to attain a speed of 116 miles an hour, although the cylinder volume of its six-cylinder engine is less than a Ford’s. The maximum engine speed is more than 5000 revolutions a minute A speed of 168 miles an hour— close to three miles a minute —was made by Malcolm Campbell, when he broke the British ‘flying kilo- meter’ record recently in the powerful car shown below. This record, which equals airplane speed, was established on the smooth sands of Pendine, in Wales easseeagees oe ell January, 1925 Jant Newest Marvels of the Speedway | 7

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‘y, 1925 January, 1925 POPULAR SCIENCE MONTHLY 47 YY! The Atom’s Amazing Secret of Power near Solution? Efforts under Way to Unloose Limitless Stores of Energy — 7 - mere fact that no one N A laboratory in Sheffield, England, I a scientist is working on what may be the most dangerous experiment in the world—in an effort to release the tremendous power locked in the atom. Apprehension is felt by the country folk about; there is an attitude of tense watchfulness and hidden dread. The experimenter stands by an electrical ap- paratus, reaches out, and turns a switch. For many months Dr. T. F. Wall, noted engineer of Sheffield University, has been doing this. He is attempting to disrupt the atom and release its energy by means of an extremely powerful magnetic field. Some day, possibly at a terrible mo- ment, the great current of electricity which he is loosing through that simple motion, may accomplish the end toward which he is working. The result no man can prophesy. Will there be a gigantic shock, a blind- ing flash, swallowing everything? The destruction of the world? Will the terrific energy of a single atom be com- municated to adjoining atoms until the world, the stars, the whole universe are reduced to electricity? One instantaneous whiff of energy released with a terrifying detonation, and after that—nothing? Or will that mo- ment be a quiet one, with a man standing there motionless, awed by the realiza- tion that he has dis- covered the greatest secret of all ages—a method for releasing and controlling the gigantic forces be- lieved to be impris- oned in the atom. OST of those working with ~ the atom today offer reassurances. There will be no cataclysm, they say. As man learns how to release the atom’s energy for his own use, he will learn, also, how to control it. But the knows is enough to explain in some de- gree the fears some people express. Consider a body so minute that 6,000,000 like it could rest on the point of a needle... This is the atom—the atom that scientists are tearing to pieces and hope to find alive with power beyond human conception. By G. B. Seybold In a pint of water there is enough of this mysterious power to drive the Leviathan across the Atlantic and back! World’s Greatest Riddle HE United States Bureau of Standards recently asserted that the most outstanding scien- tific accomplishment of the dec- ade is the exploration of the atom. Atoms are at once the smallest and most wonderful things in the world. Everything in the uni- verse is made of them. They are so small that 6,000,000 of them could sit on the point of a needle. Yet many scientists believe that each tiny atom is literally alive with power beyond human conception. There is energy enough in atoms, they say, to run the wheels of the world. Other investigators are less credulous, believing that atomic energy is found only in radioactive sub- stances and will be forever out of the reach of man. In nearly every part of the world men are exploring the atom, seeking to capture and harness its tremendous power. Dr, T. F. Wall, noted engineer of Sheffield University, in his labo- But this force, so tremendously de= structive, could also be the greatest bene~ factor of mankind. Enough of it to. rum the machinery of the world indefinitely. Enough in a chunk of mud-to run an automobile for weeks! A vast untapped force to make coal, oil, and all other exist- ing sources of energy obsolete!. Enough to do the work of the world, to change civilization on this earth! The modern view is that everything in our universe, including ourselves, is made up of atoms, each comprising a nucleus with a number of electrons whirling about it in fixed orbits, just as planets revolve about the sun, at a tremendous rate of speed, as great as 93,000 miles a second. No one ever has seen an atom, and no one ever will, for we see only by means of light, and the atom is so small that it escapes detection by the vibration of light waves. No microscope, no matter how powerful, ever can help us. If a drop of water were magnified to the size of the earth, an atom in the liquid would appear the size of a baseball. Consider the Yale Bowl an atom, and an electron speeding in it would be the size of a gnat. HE nucleus is still smaller than an electron. Give the atom a diameter of one mile, and an electron in it would be as large as a dining-room table. Then place a pea in the center of the table. That represents the nucleus. The number of electrons in an atom and the structure of its nucleus determine whether ‘the substance is-gold, iron, or some other element. In all except the simplest atom, that of hydrogen, the electrons revolve around the nucleus in successive rings. Those traveling in orbits nearest the nucleus: revolve with the greatest speed. When any of these electrons are forced, out of their path- ways, dragged ° far- ther away from the nucleus, a_ great amount of energy is released. Some of the energy of mo- tion that the fast whirling electron had in its own orbit is lost when the elec- tron jumps, and this ratory experimenting with the apparatus he devised in attempts to disrupt the atom and release its en- ergy by subjecting it to a powerful magnetic field lost energy is re- leased in the form A child could hold in the palm of its hand a metal brick containing enough explosive energy to blow up Los Angeles! In an ordinary motor-truck could be carried enough concentrated energy to level half a nation! of waves. If the nucleus of an atom; can be attacked and destroyed, the whole atom can be disrupted, causing the elec- trons to be shot out of their orbits. This actually can be seen in the case of radium by a remarkable instrument that photographs what is happening in the

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48° interior of an atom. As particles flying from radium pass through a gas, they electrify atoms in their path, and small drops of moisture forming on these make a trail of mist, which can be photo- graphed. Thus, though the atom itself will forever remain invisible, its travels ean be observed readily. ‘TBs photographic apparatus has re- vealed that a radium atom behaves just like any other atom for one or two thousand years—its electrons traveling in fixed orbits around a nucleus—then sud- denly it explodes, throwing off a new atom, that of the gas, helium. And in this process, when the particles are being shot off at high speed, the radium is being changed into lead. Transmutation of matter is taking place. The: high speed electrons in the atom, explains Doctor Wall, are like electric cur- rents, and produce in the atom _ intense magnetic fields of such strength that hitherto it has been impos- sible to produce any- thing as great by artificial means. But, if it were possible to produce a magnetic field as powerful as those in the atom, and this field were impressed on the atom, he argues, the orbits of the electrons would be so disturbed that the structure of the atom would be broken down, and some, or all, of its energy would be re- leased. Doctor Wall has obtained a magnetic field 20 times more intense than any ever known before, by »inding several lay- ers of thick insulated copper wire around a small tube of steel. This is immersed in a large glass tank filled with transformer oil, and huge quantities of electricity are discharged through the oil-immersed copper. The result is that an extremely powerful oscillating electric current flows in the coil for a small fraction of a second, pro- ducing a correspondingly intense mag- netic field, which passes through the steel tube. For a minute fraction of a second, the apparatus is capable of permitting an equivalent of 200,000 horsepower to be supplied to the coil. This intense mag- netic field is impressed at regular inter- vals for days, weeks, and even months, on the material whose atomic structure it is desired to change. Steel was used as the material for the first test, because it was discovered that any change in the positions of electrons in the atoms of steel, alters the magnetism of the metal, either weakening or strength- ening it, thus forming a valuable guide to what is going on. As an incidental result of this experiment, a way may be DISTURBED em en ee ELECTRONS | How Doctor Wall is trying to release the energy of atoms in a steel tube by surrounding the tube with a tremendously powerful mag- netic field. According to the accepted modern theory, each atom is composed of a nucleus around which whirl electrons in fixed orbits at terrific speed, as shown at the right, much as the- planets revolve around the sun. Doctor Wall believes that by dragging them out of their orbits he can free their energy of motion in the form of power waves POPULAR SCIENCE MONTHLY found to improve definitely the inherent magnetic qualities of iron and _ steel, which, in itself, would be of tremendous importance industrially. So far as Doctor Wall’s work has pro- gressed, a remarkable phenomenon has been observed. At some stages the dis- charge current in the coil around the piece of steel increases to an enormously greater value than would be expected from calculations. An instability of cur- rent is being reached, which means that the strength of the magnetic field is in- creasing beyond all expectations. With a further increase of power, the strength may go on increasing without limit, until the dramatic moment arrives when the atom is shattered. Doctor Wall now is modifying his ap- paratus so that it is expected to give at least twice the strength of magnetic R. WALLIS TRYING TO FORCE ELECTRONS FROM THEIR ORBITS BY MEANS OF AN INTENSE MAGNETIC FIELD o- MAGNETIC FIELD January, 1925 the atom. While the English scientist jg trying to pull electrons out of their orbits by producing a great magnetic field, Dr, Gerald L. Wendt of the Phvsics and Chem-: istry Department of Pennsylvania State College is attempting to do the same thing with heat. In his experiments he is using a temperature of 60,000° F., which is six times as hot as the heat of the sun, and 20,000 degrees hotter than the hottest star. This is obtained by using 100,000 volts of electricity. The American scientist places a tung- sten wire in a vacuum tube through which he shoots energy, in the hope that more energy will come out than went in, and that the tungsten will be trans. formed into helium. _ Transmutation of metals is seen to be linked closely with’ the problem of how to release atomic energy. For when one element is changed into another, accord- ing to the theory of modern science, it means that one or more electrons have been added to or sub- tracted from each of its atoms. And when this happens, the elec- trons moving into their new orbits re- lease energy. NTENSE heat was responsible for the reported transmuta- tion of mercury into gold recently by Pro- fessor Miethe, of Ger- many. By subjecting quicksilver to tre mendous heat in an electric furnace, one of the 80 electrons in the quicksilver atom was dislodged, he explained, leaving a nucleus surrounded by 79 electrons, which is the structure of the gold atom. When this electron was forced from its orbit, energy was released. field obtained in any of the previous measurements. ; [t IS conceivable that we may learn shortly how to get at the power that some day will enable us to hold the engine of a motor-car in One hand. Instead of the tons of coal we buy every winter, we may release the energy contained in a two-pound lump, knowing that there is enough there to heat a large house at a comfortable temperature all winter. Great as is the interest in thé efforts of Doctor Wall, the experiments of others are attracting equal attention. In fact, one hundred trained minds in several countries are working patiently, with different methods to harness this tre- mendous power. To one or the other of their laboratories may come success at any moment. Scientists working in America agree with Doctor Wall that it will take some tremendous force, something much greater than anything we now have, to disrupt Recent experiments of Doctor Nagaoka of Tokio University, Japan, who is said to have succeeded also in obtaining gold from mercury, are being watched closely by those trying to learn how to release atomic energy. Dr. Robert Andrews Millikan, the dis- tinguished American explorer of the atom, is attempting to discover the secret by studying the tremendous changes taking place in the stars, where physical condi- tions often transcend those of earth. Sir Ernest Rutherford, President of the British Association for the Advance- ment of Science, doubts that great stores of energy exist in every element, but believes that this is true only in the radio- active substances, radium and thorium. But, if we could find some way to quicken the exploding process going on in radioactive substances, so that the whole cycle of their disintegration could be confined to a few days instead of being spread over thousands of millions of years, Sir Ernest thinks that these elements would be valuable sources of energy. Ja o@wes da LHL!) Zaaes sos Ja er of eS,

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ary, 1925 ientist ig 2ir orbits ield, Dr. d Chem.- : ia State me thing is using ch is six sun, and hottest 100,000 a tung- } through ope that went in, e trans- en to be f how to hen one changed - accord- heory of nee, it one or ns have 0 or sub- each of nd when the elec- 1g into ‘bits re- neat was e for the nsmuta- ury into by Pro- , of Ger- ibjecting to tre it in an ace, one slectrons icksilver slodged, leaving rounded 1s, Which re of the When n was ts orbit, released. ePriments iversity, icceeded ury, are rying to py. the dis- 1e atom, pcret by s taking il condi- th. dent of .dvance- it stores ant, but le radio- rium. way to roing on hat the mn could of being of years, slements orgy. January, 1925 POPULAR SCIENCE MONTHLY 49 An Idea Worth $10,000 How a Child’s Play Developed a Profitable Invention By Roger B. Hull are not hard to find when we open our eyes and look around. The working idea for a new toy that has made me a clear profit of $10,000 and repaid the entire cash investment in the past year, was right under my feet for months before I saw it. One Sunday afternoon my children were playing on the floor with toy auto- mobiles, as they had done countless times before. When my little daughter stopped her ‘‘yellow taxi’? at the umbrella stand and stood there turning an imaginary crank, out of sheer curiosity I asked her what she was doing. “Why, I’m filling my car up with gas, daddy.” [= for money-making inventions A toy filling station! In all the years , that automobiles—touring-cars, trucks, taxis, and busses—have been furnishing models for popu- Roger B. Hull is a Wall Street attorney by profession. But the invention that he began as a pastime has grown to a business of such proportions that he has had to establish separate offices to handle it. In a year, more than 2,000,000 of his toy gas stations have been distributed by chain stores lar toys, no one had ever realized the possibilities of a miniature filling station. Im- mediately I saw how it would add to the delight in toy autos to have somewhere to run them and something to do when they got there. It was a good idea; I was confident of that. But I never possessed any pronounced mechanical bent. Besides, I was busy with my law practice, and turning the thought of a toy gas station over in my mind occasionally was as far as I got for two years. Then one winter I began spending my evenings whit- Beverly Hull, age 9, playing with the toy gas sta- tion, the inven- tion of which net- ted her father a clear profit of $10,000 during the last year tling out a model. It was fascinating work. My fin- ished wooden model had a rubber friction drive to run the gas indicator up and down, and was equipped with a rubber hose. The shaft of the crank projected slightly from the side, and clicked against a bit of steel as it turned, thus providing the necessary noise. I had discovered that a toy must have action, noise, and imagination to capture a child’s interest. But I still knew so little about the cost of materials that in working for a cheap toy, I had built an expensive one. In my spare time I called upon toy manufacturers and asked them to recommend a_ practical mechanic who could help me put my wooden model into materials that would make it practicable for production as a cheap toy for big distribution. In this way I eventually The toy filling sta- tion as perfected for the market (left), and the first wooden model that Mr. Hull made by hand found a mechanic who had been a toy manufacturer. Together we devised a new mechanism using a ratchet wheel and pinion, and he made the dies for a tin model. The first tin gas station looked splendid in comparison with my crude whittling, but it ran too well. There was no noise. Our problem finally was solved by placing the indicator on a tiny ‘‘ washboard” that moves up and down as the crank turns. Making the ratchet wheel and pinion movement loose enough to let this corru- gated tin strip slip a little with each turn of the crank produces the desired racket. Then, as a ‘‘safety” feature, we added a spring to hold up this strip, so that the child can turn on and on without injury to the toy. When the crank is reversed and the indicator goes down, the spring gives the same protection at the bottom. INDING a cheap substitute for the rubber hose line presented consider- able difficulty. But twine, with a tin ferrule on the end to give the impression of a hollow interior, finally was adopted as the next best thing for a 10-cent toy. I first offered this novelty to the large refining companies as an advertising medium. They were skeptical. So I went to see the toy buyer of one of the largest chain-store corporations in the country. And I may add that I haven’t needed to worry about distribution since. From the moment he saw that little gas station, he knew it would sell. The idea I picked up off the floor already has grown into an incorporated concern for the toy station and other novel playthings suggested by the games of my children and their playmates.

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50 POPULAR SCIENCE MONTHLY Huge “Water Wings” January, 1925 Float Resurrected from the watery grave of the German battle fleet in Scapa Flow—a destroyer floated by two huge balloon pontoons that are fastened to the bow of the ship, one balloon on each side ~ cs Lifted and held afloat by mammoth “water wings,” the weed- covered destroyer is towed ashore to be broken up and sold as scrap. Each of the balloon pontoons is capable of lifting 150 tons Cheating Davy Jones. This photograph shows a salvage crew removing heavy fittings, turrets, and guns from the dilapidated decks of one of the German destroyers raised after five years in the sea ACING constant danger and thrilling adventure in the murky FR depths of a naval graveyard, the crews of a salvaging com- pany are engaged in raising the surrendered German battle fleet that was scuttled by its own crews at Scapa Flow, north of Scotland, on June 21, 1919. FLOATING DOCK ‘ LEANN Pe ta. a, PART OF GERMAN SUS MARINE, DOCK ADAPT ED FOR SALVAGE PURPOSES How the scuttled destroyers are raised by cables from two halves of a surrendered German submarine-testing dock. Lifting cables hooked into portholes of the sunken ship are manipulated by hand winches operated by balanced teams of men on each side of the dock Of 51 war-ships sent to the bottom, the salvaging company purchased from the British Admiralty 24 destroyers and the two great battle cruisers Hindenburg and Seydlitz. The illustrations on these pages show the spectacular methods by which Davy Jones already has been cheated of a number of Ger- Ja aan f

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25 any is by Ger- January, 1925 POPULAR SCIENCE MONTHLY 51 BRIDGE OF DESTROYER ASOVE WATER PONTOON WITH In the first attempt to raise the destroyer V-70 by this method the heavy cables snapped under the weight of the destroyer and the tons of water in which it was sunk, their broken links raking the decks of the pontoons and endangering limbs and lives of the workmen man destroyers, including the S-131, the V-70, and the S-53. By one method huge balloon pontoons are deflated, submerged, and attached to the sunken ship. Then the air is pumped into the odd céterpillar-like bags, which lift the vessel slowly to the surface. A second method, pictured in the center illustration, utilizes a Scuttled German War-Ships One of the greatest tasks is that of raising the battle cruiser Hinden- burg, which rests upright on a sandy bottom in 60 feet of water, its turrets and funnels above water and its decks awash at low tide ; ay) The foredeck of the German destroyer S-131 after five years’ im- mersion, showing gun incrusted with marine growths. Note the solitary seagull standing on one leg on a dilapidated davit This immense chain cable was snapped as easily as a daisy chain by the tremendous dead weight of a sunken destroyer. The man in this weird picture is exhibiting one of the cleanly broken off links reconstructed submarine-testing dock surrendered by Germany as a basis for lifting operations with cables and winches. The floating of the battle cruisers Hindenburg and Seydlitz probably will be attempted next spring by closing all sea inlets of the sunken ships and pumping out the water.

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52 By Truman Stevens in Toulon, France, not long ago, sat a man suspected of counterfeiting. Half a dozen police officers were questioning him closely, but his glib an- swers, apparently made with the utmost frankness, were plausible enough to be quite disarming. True, he admitted, he had served a prison term for counterfeiting, but he had learned his lesson and reformed. He was now law-abiding, satisfied to earn a meager living in his café in Marseilles. More than five years had passed since last he had seen a [: THE office of the Prefect of Police Dr. Edmond Locard, director of the police technical laboratory, Lyons, France, and his microscopic camera which has _ solved some of the most baffling mysteries POPULAR SCIENCE MONTHLY January, 1925 Crime Mysteries Bared by the Microscope Sherlock Holmes Outdone by New Science even in specks with which the section had been flooded? Vainly the police sought to make him confess. The man denied everything, and at last the prefect gave a sign that the questioning was at an end. ‘*Before you depart, though,” he said to the man, “‘our physician will examine you. Merely a little precaution in the interest of public health.” Happy that he had carried off his part so successfully, the man submitted will- ingly to the perfunctory examination by the physician; then departed after bid- ding his inquisitors an extravagant fare- well and expressing the hope that they would be successful in catching the counterfeiter. ‘ The man got his wish, for two days ern nae Amazing stories of how a modern detective, armed with an instrument that magnifies 50,000 times, finds murder clues of telltale dust later the police called at his café and again took him in custody, and this time his protestations of innocence availed him nothing. For the police had evidence that eventually resulted in his conviction. He himself had unwittingly supplied it during the physical examination, in a tiny specimen of wax which the physician had taken from his ear! HIS bit of wax had been forwarded to Dr. Edmond Locard, director of the police technical laboratory at Lyons, who had photographically enlarged it with his microscopic camera, a device of his own invention, which has proved of incalcu- lable aid to the police in unraveling some of the most mysterious crimes that have occurred recently in France. Magnified 225 diameters, or more than 50,000 times, the speck of wax showed telltale streaks of printer’s ink, particles of dust readily identified as from a litho- graphic stone, and traces of characteristic crystals of a chemical used by engravers, undeniable evidence that the prisoner’s story was a fabrication. And this was only a single instance of the amaz- ing uses to which the Locard microscope printing press or an en- graver’s tool. How, then, could the police suspect him of any part in preparing the spurious 100-franc notes Particles of iron, chemical crystals; and dust in a speck of wax taken from the ear of a suspected counter- feiter and magnified 50,000 times by -the super-microscope. This photo- graph was accepted and used as important evidence in the man’s trial Magnified 50,000 times, a speck of dust beaten from the clothing of a Parisian suspected of counterfeiting nickel one-franc pieces revealed these nickel alloy shavings. This evidence led to conviction after he had offered a most convincing alibi recently has been put in the detection of crime. Centuries ago it was con- sidered good police practice (Continued on page 147) Jan —— ooanodceas'd a

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ry, 1925 nce fé and is time availed idence riction. lied it , ina ysician ‘ded to of the s, who ith his is own icaleu- y some t have ‘rance. neters, times, howed inter’s -eadily litho- aces of B01 2 ravers, that was a nly a amaz- Locard r has tion of iS cOn- ractice 7) January, 1925 POPULAR SCIENCE MONTHLY How to Build a House thas Will Save Half Your Coal Surprising new tests show that with an inexpensive overcoat frame walls resist cold as does 16-inch brick By Newton Burke Ts winter the people of America will waste not less than $100,000,- 000 trying to heat their homes, this amount representing by a conserva- tive estimate the value of about 8,000,000 tons of coal that experts say will have been shoveled unnecessarily into Ameri- can furnaces or stoves. This reckless extravagance means an actual loss in dollars and cents to every one in the country, for you share in the waste, whether you buy coal to burn in your own furnace, or help defray the need- lessly large coal bill of your landlord in the form of rent. Most persons who stoke a furnace through the winter— their own or some- body else’s—learn to use coal economically. Also, the average home heating plant is not only efficient, but literally fool- proof. Whence, then, comes this appalling waste, amounting vir- tually to half the domestic fuel bill of the nation? ECENT scientific investigations, which uncovered the which will prevent the furnace heat from escaping outward, and conversely also will keep the hot rays of the sun from making the house overwarm in summer. It has been determined that a house of good frame construction, with a single inch of efficient heat-insulating material in its walls, will be protected from the cold of winter and the hezct of summer as effectively as though its walls were of brick 16 inches thick or of concrete 26 inches thick! Moreover, such a house will save its occupants money in coal, not waste, place the blame on the wholly unscientific methods employed in con- structing most of our dwelling houses. The average dwelling, the investigators assert, is so built that only between 40 and 50 per cent of the heat of the coal consumed in its furnace is utilized to make the house comfortable for its inhabitants. The rest is lost in leakage through walls and roofs —particularly the latter—and this condi- tion of unscientific construction involves practically every type of house, from the modest bungalow to the big apartment house or hotel. The investigators have determined, among other things, that at slight addi- tional expense—-the cost of one winter’s coal supply in the average case—a house can be so constructed that the cost of heating will be cut in half. The secret lies in supplying insulation for the walls and roof; heat-resistant materials, such as cork, sawdust, or wool, sheathing and _ shingles. investigation shows that a house of good frame construction, with a single inch of efficient heat insulating material in its walls, A Felt- Sina Gianmanem for the Home Insulating the walls of a frame house by placing a lining of asbestos felt between the Recent scientific only because it will require less fuel to operate the furnace, but because a fire need not be started so early in autumn, nor be kept going so late in spring. The heat of the sun, too, can readily be called into service as an auxiliary furnace for a properly insulated house with conse- quent saving of coal. Indeed, one inves- tigator, James Govan, an architect and inspector of hospitals for the Ontario Gov- ernment, states without reservation that under proper conditions, the sun alone can be used to heat a house comfortably through the whole winter! This, he de- clares, can be accomplished by placing the house with full exposure and an abun- dance of windows to the south and supply- ing adequate protection against heat losses on the other sides and in the roof. will be protected from winter cold and sum- mer heat as effectively as if its walls were of brick 16 inches thick, or of concrete 26 inches thick. A house so insulated, tests show, may reduce the winter coal bill 50 per cent and shorten the furnace-using season for you That this amazing suggestion is en- tirely practical I can testify from personal experience. Last winter I called on a friend who had just moved into a new home in Washington, D. C. The heating plant had not yet been installed, and yet the house was warm merely from the sun. Moreover, my friend and his family occupied the house without discomfort during a whole week of severe weather until the furnace was ready. This house, of course, was insulated against heat losses and had adequate storm sash and weather stripping. NDEPENDENT investigation of the subject of heat conservation through insulation has so established its im- portance that re- cently a central com- mittee was formed under the auspices of the National Re- search Council to in- vestigate fully every phase of the question. Serving on the com- mittee are chemists, physicists and _ en- gineers representing the United States Bu- reau of Mines, the Bureau of Standards, the engineering de- partments of Har- vard University and the University of Michigan, as well as large industrial or- ganizations. Through the work of this committee the findings of previous investigators un- doubtedly will be crystallized and standard construction methods pointing the way for the Ameri- can householder to cut his yearly coal bill in half, will be worked out for various types of houses. Meanwhile, though, let us see what scientists already have found out. Both walls and roofs have been found responsible for the escape of heat, espe- cially the roofs, because warm air rises. Evidence of this is found in the rapidity with which snow melts on the average housetop even in severe weather. The old theory that a dead air space between walls is sufficient to prevent the escape of heat has been disproved. The investigators found, on the contrary, that hollow wall construction aids the escape of heat through convection—that is,

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54 movement of the heated air in the wall spaces, the hollow construction supplying a sort.of chimney through which the hot air rises as rapidly as it is supplied by the heating plant.’ é. Saee way to utilize dead air spaces in walls scientifically is to break them up so that, instead of having one great hollow wall extending from cellar to attic, you have a very large number of tiny dead air spaces separated by heat-resist- ant materials, preventing the warm air from traveling from one to the next. The simplest and most economical way to supply these is to pack the hollows be- tween walls tightly: with wood wool, pure wool, mineral wool,;-hair felt, cork board, STUDS-WOOD SHEATH AND OROP SIDING - W PLASTER INSIDE. « STANDARD QaD SHEATH ~ TWO-BY-FOUR 11% TONS ANTHRACITE COAL ATSIGATON — 4180 How Insulation Cuts Coal Bills This illustration, based on actual tests at the Armour Institute of Technology, Chi- cago, shows the amazing extent to which winter coal bills can be cut simply by in- sulating the walls of a frame house of standard construction. Three inches of wall insulation and four inches in the ceiling reduced the winter coal consumption from 1134 to 4% tons, a difference in cost between $180 and $72, or a saving of 60 per cent rock cork, or various manufactured products that can be utilized for the pur- pose. A wide variety of materials is available, the only requirements being that they be poor conductors of heat, unlikely to be- come breeding places for germs and ver- min, and easy to handle. Since most heat-stopping materials are little more than refuse, they can be purchased cheaply. This is why the investigators say that any house under construction can be insulated effectively for a cost not exceeding half of one year’s coal bill. However, insulating the walls alone will not suffice. It has been determined by scientific test that in a house with walls insulated by four inches of mineral wool and its roof protected only slightly, the saving of heat effected by wall protection is largely offset by the loss of heat through the roof. Even though both walls and roof are insulated, loose windows, poor workman- ship in installing windows and doors, and lack of weather stripping and storm windows may cause leakage sufficient to make heavy inroads on the coal supply. ~BUILDING PAPER LATH AND LIME POPULAR SCIENCE MONTHLY © Failure to apply wall sheathing, and the use of green lumber, which in drying opens cracks in the plaster and works out of place, likewise may undo the good done by-insulation. In a well insulated house, equipped with storm sash and weather stripping, covering the furnace pipes with asbestos effects a further saving in fuel. The foregoing may be taken as the high points of the several investigations of the insulation question conducted in this country, Canada and Norway. Specific instances of the experiments through which these results were achieved are even more significant. Professor James T. Peebles, of the Armour Institute of Technology, Chicago, STANDARD CONSTRUCT _AMSULATION 7-677 18) bs) " ANTHRACITE COAL ATFIGATON — £72 studied in the laboratory the problem of heating a detached bungalow, 26 by 32 feet, with a 10-foot ceiling, through 200 days with an average outdoor tempera- ture of 33 degrees. For 16 hours each day 70 degrees was to be maintained within, and 55 degrees during eight hours’ sleep- ing time. HE first house was built of two-by- four studs, with walls of wood sheathing, building paper, and drop siding, and with wood lath and lime plaster inside. The ceiling construction was wood lath and lime plaster on the lower side of wood ceiling joists. Single windows were used, and there was no attic flooring. With this construction, which is recognized as standard, 1114 tons of anthracite coal at a cost of $180 were required to heat the house. With the addition of two inches of in- sulation between wall studs, and three inches in the ceiling, only 614 tons of coal were required, the cost dropping to $100, while with three inches of wall insulation and four inches in the ceiling, the coal consumption was only 41% tons and the coal bill only $72, the price of coal being $16 a ton. Quite as remarkable results were achieved in a study of a brick house of the same size and plan. Three inches of in- January, 1925 sulation in the side walls and four in the ceiling resulted in reducing the yearly coal bill from $117.50 to $49.60. Recent tests performed by scientists of the United States Bureau of. Standards yielded results equally amazing. In these tests standard types of wall construction — were reproduced in the laboratory, and their heat-resistant qualities determined, Here, too, it was demonstrated that properly installed heat-resistant materials in the walls and roofs of dwellings will enable the owner to reduce his annual fuel bills by 50 per cent or more. TWO-YEAR test of 27 small houses sponsored by the Norwegian govern- ment and completed recently added to STANDARD CONSTRUCTION WITH 2° OF INSULATION BETWEEN WALL STUDS AND 3" IN CEILING 6/4 TONS ANTHRACITE COAL AT#HIGEATON — #100 iw? — = the evidence regarding the importance of insulation. These houses were of uni- form design, identical as to ceilings, floors, doors and windows. The only variation was in the type of walls. A single electric heating plant served them all in regulated quantities. A frame house, containing heat insula- tion in the form of a four-inch layer of sawdust covered with a single sheet of asphalt pasteboard, made the best score in economy of heat and retention of heat, despite the fact that other houses were of brick, cement block, reinforced concrete and similar sturdy construction. This test also demonstrated the amazing fact that a frame house, properly insulated, is heated more efficiently and economically than a brick house, according to conclu- sions drawn by Prof. Andrew Bugge, of the Norwegian Technical University. Professor F. B. Rowley, of the Univer- sity of Minnesota, is another who has demonstrated that heat loss is reduced by insulation. One-half inch of insulating material placed between the studding of a wall constructed with inside plaster, sheathing, tar paper, and drop siding, Professor Rowley reports, will effect a saving of 26 per cent in heat loss. You would search in vain for a bank that would give you a mortgage on your home at four per cent. Yet the saving on your coal bill that you can effect through insulation of your home easily may repre- sent the difference between a rate of six per cent and four per cent on a mortgage. ~~ tm Ome em ODO Ot

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ry, 1925 in the yearly tists of ortance insula- ayer of Goliath of By Fritz Blocki HE simple principle of physics that causes air bubbles to rise to the surface of water has been applied in the design of a mammoth new type of lock for lifting ships of large tonnage from one level to another in a canal. The photograph above shows a model of the new invention, which attracted much attention at a recent technical exhibition in Berlin, Germany. It is the work of George Ollert, inventor, and Hans Rott- mayer, architect, both of Berlin, and was designed for use in the Welland Ship Canal between Lake Erie and Lake Ontario. Two of the locks, they calculate, would take the place of the series of locks now in operation in the canal. The invention is designed to lift ves- POPULAR SCIENCE MONTHLY Locks for Ship Canal Mammoth Water-Towers to Lift 25,000-Ton Vessels sels of 25,000 tons, in addition to the 60,000 tons representing the weight of the water-filled trough or basin that holds the ship, and of all movable parts of the lifting mechanism. Each of the four large towers shown in the picture are filled with water, and at the top of each is a giant air-filled float supported by the water. Extending downward from the four floats are four rods suspending two cross beams that support the large steel lifting trough. This trough has gates at each end. The arrangement is such that the pressure of the water on the floats in the towers exactly balances the combined weight of the water-filled trough and the ship. Thus the trough really acts as a cradle floating on the water contained in the four towers. On each side of the lock, between the large water-towers, you will observe a smaller tower. Both small towers are used for the actual lifting process. Each contains a piston connected at the lower end with a cross beam supporting the lifting trough in the middle. Since the ship, resting in its floating cradle, is held in suspension, lifting the load is accomplished simply by forcing compressed air against the pistons in the central towers. Lowering is accomplished in a similar manner. Of the two locks designed for the Welland Canal, one would be capable of lifting a ship 131 feet; the other to a height of 207 feet. The structures would be of reinforced concrete. The larger one would be 688 feet long and 574 feet high.

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Artificial Sunlight to Make Weak Children Strong Secrets of health found in violet rays—The X-ray for every- POPULAR SCIENCE MONTHLY January, 1925 day jobs—Other important new developments in science S A result of amazing experiments A recently completed at the Uni- versity of Maine, scientists believe there has been put in their hands a means of controlling the dread bone disease, rickets, the chief cause of bow legs and of other more serious deformities of the limbs from which children suffer. These experiments, conducted by Dr. C. C. Little, president of the university, and Dr. W. T. Bovie, professor of biophysics at the. Harvard Medical School, in cooperation with the General Electric Company, were performed on a flock of 233 chicks. They demon- strate the importance of sunlight in human health, particularly as a factor in the physical development of young children. , The chicks were divided into three groups. All were given the same diet, but one group was kept in natural sun- light, the second in natural sunlight pass- ing through window-glass, while the third was kept in natural sunlight and exposed at intervals to strong ultra- violet rays from Cooper-Hewitt lamps of fused quartz. The first group of chicks developed normally. All of the second group— those that received the sunlight through window - glass — de- veloped rickets. Those of the third group in 10 weeks reached the same stage of physical de- velopment that those raised in natural sun- light only attained in 12 weeks. The conclusion drawn from the ex- periments is that the ultra-violet rays of the sun exert a most tremendous influence on bone growth. This is amply substanti- ated by the larger growth of the chicks that received direct application of the ultra-violet rays, and by the development of _rickets by the chicks raised under window-glass, which screens out the ultra- violet rays of the sun. Further evidence was supplied by the fact that the rickety

chicks were speedily cured when sub- jected to ultra-violet ray treatment. And science, of course, seeks to apply the re- sults of the experiments to the prevention and cure of rickets in children.

Capt. A. I. Eagle of the U. S. Army Air Service, filling a tank on his plane with sand preparatory to the recent rainmaking tests Science also sees in the results of the experiment an explanation of the fact, long known, that between 97 and 100 per cent of the children born in the summer and autumn develop rickets in some de-

The Weak and the Strong This photograph shows the amazing effect of ultra-violet rays on the growth of young chickens. Both chicks are four weeks old, from the same brood and raised under iden- tical conditions, except that the larger and healthier chick was treated 15 minutes daily with ultra-violet rays. The small chick lived under natural sunlight filtered through window-glass, which eliminated the ultra- violet rays. Babies deprived of outdoor sun- light, experimenters say, are similarly affected

at Bolling Field, Va., gree by the following spring. Through the winter the mothers of recently born children fear to subject them to the bitter cold; hence, the babies re- ceive their “‘sunshine” in glass-inclosed

when aviators suc- ceeded in entirely dispelling a series of clouds by blasting them with electrified sand porches, or from behind closed windows. That more children are not crippled permanently by rickets from this cause is due to the fact that the beneficial effects of ultra-violet rays on the growth of the bones are apparent almost imme- diately when children kept indoors dur- ing the winter are subjected to the direct rays of the sun. It makes no difference what portion of the body receives the sun- light; the effect of the rays is trans- mitted through the whole body. Fused quartz does not absorb the ultra- violet rays. It is so expensive to produce at present, though, that it is unlikely it will soon find general use as a substitute for window-glass, even for a purpose so important as the prevention of rickets. It is in the cure of rickets through appli- cation of ultra-violet rays, artificially produced, that science hopes the experi- ments will bear greatest fruit. Blast Clouds with Sand N MAY, 1923, POPULAR SCIENCE MONTHLY announced the success of early attempts to produce rain and dispel fog by shooting electrified sand from air- planes into clouds, forecasting the com- mercialization of the process for the bene- fit of mankind. A few weeks ago the first public applica- tion of the scientific rain-making process since its announce- ment in this maga- zine was made at Bolling Field near Washington, D. C. Two planes, piloted by Capt. A. I. Eagle and Lieut. W. E. Melville, succeeded in “shooting down” a series of overshadow- ing clouds. The process used was that described a year ago last May. It was worked out by Dr. Wilder D. Ban- croft, professor of physical chemistry at Cornell University, and L. Francis War- ren. Mr. Warren describes the process briefly thus: “We fill sand tanks on the planes with 120-mesh silica sand, the planes being equipped for charging the sand either positively or negatively by the turn of a lever. The sand, im- pinging upon the charging plates or falling through charging nozzles, is scattered by

Jar the tiv és =< c 84 a a ae ee ae a ee ee oe

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ry, 1925 .e ry: rindows. crippled is cause eneficial growth t imme- ors dur- e direct fference the sun- 3 trans- 1e ultra- produce likely it bstitute ‘pose so rickets. h appli- tificially experi- ind SCIENCE 2cess of d dispel rom. air- he com- he bene- ind. A igo the applica- cientific process nounce- ; maga- ade at d near D.. «Ce piloted [. Eagle W. ECE. eeded in wn” a shadow- ss used escribed st May. l out by ). Ban- sor of ‘istry at versity, is War- Warren process id tanks 2s with ‘a sand, harging yatively nd, im- r falling ered by January, 1925 the air and driven back by the propeller. “When a cloud is found to have a posi- tive charge, we scatter negative particles at the extreme top, and vice versa.” The ‘Crazy Gas’’ Scare Sip py ahaa LEAD fumes, or ‘“‘crazy’” gas, which was declar- ed responsible for Looking through Walls How the new portable X-ray equipment is used by workmen to locate pipes and wires within a house wall POPULAR SCIENCE MONTHLY animals, it reports that the danger to the public from breathing lead in the exhaust of automobiles is “seemingly remote.” Dr. Yandell Henderson, professor of applied psychology at Yale, one of the greatest authorities on the action of gases on the human body, disagrees with this. It is not only very dangerous when handled in concentrated form, he says, but the exhaust of ethyl gas diffused the deaths of five work- men at the Standard Oil Company manufacturing plant at Bayway, N. J., re- cently, has aroused a storm of controversy. Besides the fatalities, 36 men _ were taken to the hospital for treatment, several showing symptoms of insanity. The Standard Oil Company has discontinued manufacture of the compound tempo- rarily. Chemists have known tetraethyl, a compound of lead and alcohol, since 1854, but the discovery of its value as an _ anti-knock compound for automobile gasoline is recent. It is diluted with 1000 parts of gasoline, the final product sold being known as ethyl gas. The extent of danger involved in the compound falls under three divisions: Danger in the manufacture of tetraethyl lead; danger in handling it, and danger in using it. In the manufacturing process, it is handled in concentrated form. It is sold in pure form to garages and filling stations, where it is then added to the gasoline. Any hazard to the consumer would come in inhaling the exhaust of engines using it. The Federal Bureau of Mines is in- vestigating all three classes, but has announced its conclusion only on the last. As a result of 10 months’ investigation of the effect of the gas on various types of through the streets, offers a grave public menace. If a woman cleans her gloves in ethyl gas, she may be poisoned, made in- sane, or killed, he asserts. Dr. E. E. Smith, of New York City, a toxicologist of 40 years’ experience, says that tetraethyl-lead gas is a menace only in large industrial plants. Thomas Midgely, Jr., who discovered the process of making the compound, testified that he had worked with it for two years without suffering any harm. X-Rays Put to New Uses OB ec tet ragigeers you have seen a plumber poking blindly into a clogged pipe seeking the cause of a stop- page, or an electrician “fishing” for a wire 57 through a hole in a wall where he intends to install an outlet. Such haphazard operations are necessary no _ longer. Neither need builders trust to their in- stinct in seeking the location of a floor beam, nor must jewelers make guesses in determining the genuineness of precious stones. For there was devised recently in the laboratory of the General Electric Company in Schenectady, N. Y., a prac- ticable, portable X-ray apparatus, that weighs only 20 pounds and is operated merely by plugging into an ordinarly electric-light switch. ; The new device was developed by Dr. W.D. Coolidge, inventor of the Coolidge X-ray tube, and is designed expressly for practical use by workers in trades that ordinarily do not employ the X-ray. It is equally adaptable to emer- gency or permanent use in the scientific laboratory, or by the busy physician or dentist. The new X-ray machine is carried complete in a leather- covered wooden container, seven by eight by 10 inches, about the size of a one-tube radio set, which in appear- ance it somewhat resembles. Remarkable X-ray of a wall, revealing elbow in pipe and nails U. S. Leads in Telephones B iinearsbemsr een pride may be felt by the American who considers the latest statistics of the telephone industry. The United States wins the international tele- phone championship by possessing 63 per cent of the telephones in the world. European countries have less than half that number—26 per cent, while the re- maining 11 per cent are found outside of Europe and the United States. Omaha, Neb., leads the world with 28 telephones to each 100 persons. The next 10 cities are, in order: Stockholm, Swe- den, San Francisco, Minneapolis, Denver, Washington, Los Angeles, Chicago, Toronto, Cincinnati and New York. Paris, France, appears twenty-third in the list, and London twenty-fourth.

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POPULAR SCIENCE MONTHLY | The airplane hanging between two houses after crashing into the one at the right Safety Basket for Balloons Stays Afloat FLOATING basket for balloons has been invented to lessen two of the greatest dangers encountered in balloon accidents. Most aeronauts who have lost their lives by drowning, have done so either because the basket of the balloon sank, or became entangled with ropes leading to the gas bag. In the new invention two airtight chambers, having great carrying capacity, are attached to the outer wall of the basket. When not in use these are com- pressed like a folding camera and held in that position by a rope. If the balloon falls into water, the aeronaut need only cut the rope and the chambers are ex- panded by inrushing air. The chambers are reinforced by strong spiral springs. The other unique The balloon basket with floats attached, and showing safety releases feature of the in- *\| vention is the ease | with which the iy ropes leading to the net may be re- leased. These ropes terminate in eyes that lock in catches around the upper edge of the basket rim. When a lever is turned, the catches are re- leased so that the ropes all can es- cape at the same time, and _ thus avoidany tangling. January, 1925 Plane Crashes into House and Hangs from Roofs Paley since an airplane with pilot and one passenger recently crashed into the front porch and upper story of his home, Ralph Sweigart, of Dayton, Ohio, has wished that he did not live quite so close to the McCook Flying Field. Both of the fliers were seriously hurt and much damage was done to the frame building, as well as to the plane. After the crash the plane hung sus- pended between the house it had struck and the roof of the house next door. Aerial Photographers Wear Oxygen Masks oe taking map pictures miles above the earth, Uncle Sam recently has equipped his aerial photographers with the elaborate apparatus shown above. At the left is the equipment that sup- plies oxygen to photographer and flier in the rarefied atmosphere above about 20,000 feet. At the right is the latest type of aerial camera that has proved capable of taking remarkably clear photo- graphs of the earth from an altitude of nearly six miles. : Odd “Flying Bathtub” Airplane Wins Race and Climbs 2500 Feet HE “Flying Bathtub” is the appro- priate name given to an odd looking craft that recently won the Rickenbacker race for light planes. Ever since it was first flown to the McCook Field at Day- ton, Ohio, by its designer, Etienne Dor- moy, atechnical engineer, it has attracted much attention. The body of the monoplane, which resembles a tub, is connected with the tail piece by rods and wires. The absence of a fuselage gives the plane its appear- ance of extreme frailty. Twenty-four feet long, it weighs only 380 pounds and makes 50 miles on a gallon of gasoline. The gas tank is located on the under side of the wing, just above the pilot’s cockpit, and holds only two gallons. On Dormoy’s ursv trial flight in the Bathtub, he reached an altitude of 2500 feet. | A plane without a fuselage. The ‘‘Flying Bathtub’’ at McCook Field, Dayton, Ohio Jan We the tol she Isl sto Sasso s’ i a

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ase fs t and into f his Ohio, ite so Both much ding, sus- truck lear above y has with ve. C sup- ier in about latest roved yhoto- ide of et January, 1925 Famous Old Whaler Wrecked by a Hurricane A ANY a cruise full of adventure was made in the old whaling bark, the Wanderer. Every fisherman up and down the New England coast knew her, and told stories of the good old days, when she was in her glory. Now she is on the rocks of Cuttyhunk Island, Mass., swept there by a terrific storm. Piece by piece, she is going to her burial in the Atlantic. The famous old whaler, last of her line, had barely left New Bedford, Mass., on The whaler Wanderer on the rocks what was expected to be her final voyage —a cruise to the south Atlantic—when a hurricane hit her. During the gale the bark dragged her anchor and drifted toward Cuttyhunk. Seeing that she was headed for the shoal, the crew abandoned her to her fate, and every wave carries her nearer to her doom. POPULAR SCIENCE MONTHLY Trains “Swim” through a Flood in Boston | eee pulled by an engine through a flood was the unusual experience of passengers on trains that entered Boston recently following a severe storm. The switchman had to don his hip boots in order to wade out from the traffic tower across the submerged tracks to give instructions to the engineers. While the railway service was crippled tem- porarily, the flood soon subsided. Auto Makes a Call HIS is not a photograph of a trick scene in a motion-picture film, but the rec- ord of an actual impromptu eall made at the home of T. J. Quirk in Portland, Ore., by a woman driver who lost control of her car. Instead of stopping at the curb as she had intended, she stepped on the gas, and the car climbed the front porch steps and crashed into the living-room. In spite of the damage to house and be =e ES re BF An unwelcome guest. This car climbed the front steps and entered = car, no one was injured, except for the shock to the driver and the members of Mr. Quirk’s household. This Aviator Picked a Soft Spot, but His Plane Was Wrecked After the crash—the wrecked plane covered with hay after plowing into the stack HOUGH the aviator who made a landing recently in a haystack near Roslyn, S. Dak., escaped without so much as a bruise, his airplane was wrecked as a result of the collision. The hay was very loosely packed. For this reason one might think that the plane would have been able to plow through or ride over it without damage; but planes are de- signed to withstand only certain definite stresses, and are of necessity easily demolished in a collision. The accident was caused by striking the topmost branches of a cottonwood tree as the plane—a homemade machine, designed and built by the flier—ap- proached the ‘ground after a successful flight. The hay that was knocked from the stack fell back upon the wreckage and almost buried it, as shown in the accompanying photograph. -

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4 v2 .. - nll NEW machine, known as _ the “otheograph,” has been installed on a section of railway track at Erie, Pa., to give a graphic record of the downward pressure and lateral movement of loco- motives and railway cars passing over a certain section of track. The device makes a chart of these forces for any or all of the wheels of the vehicle used in the test. The otheograph consists of 25 special Strain on the Rails Charted and Miecasused POPULAR SCIENCE MONTHLY 5° ties covering about 50 feet of track. These are laid in place of the usual wooden ties so that the roadbed remains similar to its condition before the adding of the machine. The forces exerted on each tie as a locomotive or train passes are measured by sets of heavy springs. These are connected with a recording arm that draws a chart for each wheel on a paper cylinder. Power Plant Roof Holds Two Tall Chimneys ESIRE to economize space and building cost recently induced the owners of a power plant in Montville, Conn., to superimpose two 160-foot chimneys, each weighing about 750,000 pounds, on the structural skeleton of the power house, instead of following the usual method of erecting the chimneys directly upon a ground foundation at some distance from the building con- taining the heating plant. The ground surrounding the power house was needed for the storage of coal and no part of it could be spared for the chimneys. Moreover, it was desired to carry the tops of the chimneys to a height of 250 feet above the ground, and by placing the stacks on top of the build- ing a considerable saving in the cost of construction became possible. Each of the chimneys has an outside diameter of 15 feet 6 inches at the bot- tom and of 11 feet at the top. The mini- mum inside diameter is 10 feet. In the lower 50 feet a four-inch fire-brick lining is used. Each chimney rests on a con- crete mat 18 inches thick placed on an octagonal frame of steel girders. These girders are supported by the steel col- umns of the building structure. The lower sections of the chimneys are anchored by vertical steel rods, 114 inch in diameter, spaced about 18 inches from center to center and passing through the concrete base to the steel framework of the building. The roof of the power house does not come in direct contact with the chimneys. The lower part of each chimney passes through an opening in the roof, which leaves a space of SORE CIE ROR Se TO Two 160-foot chimneys on roof of a Montville, Conn., power plant about eight inches between the chim- ney and the roof curb. A concrete apron overlapping the curb was cast ' in a recess around ’ the chimney. The space between the roof slab and the chimney is utilized for ventilation. CERTAIN tropical hard woods are so dense that they will not float in water. They are transported on rafts of bamboo. January, 1925 Huge Generators Built for Nippon Power Plant "THE two largest vertical water-wheel driven generators ever built for for- eign service recently were completed by the General Electric Co. for use by the Nippon Electric Co. of Japan. Each generator weighs approximately 500,000 pounds. Both will be placed ina new power plant known as the “‘ Kanidera Station,” located about 180 miles inland from Osaka, a seaport and the industrial center of Japan. Power will be utilized from the Miya River at a head of 445 feet, and 1500 feet of water every second will be necessary to supply the water wheels driving the gene- rators. The current will be transformed from 11,000 to 154,000 volts by two banks of transformers. One of the two immense water- wheel generators built in the United States for the Nip- fon Electric Com- pany of Japan. Note its huge size compared with that of the men. At the left are the transformers de- signed to step up the plant’s voltage Chicago Factory Builds Its Own Water System NABLE to obtain water from the city mains in Chicago, Ill., a large manufacturing plant near that city re- cently built a unique but effective water system of its own. It consists of an un- derground pumping station 357 feet below the surface, connected by pipe lines with 10 wells, from 1200 to 1500 feet deep. The pipe lines run through properly reinforced tunnels. Sinking the shaft through water- bearing seams, driving the _ tunnels through falling shale, locating the wells and connecting them with the tunnel sys- tem were some of the difficulties en- countered by the builders. All but two wells were found within the limits of the headings, eight feet wide, and these two had drifted in drilling. Jat

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Ty, 1925 t for it r-wheel for for- ted by by the imately ed ina anidera inland lustrial 2 Miya 00 feet sary to e gene- formed yy two

two ater- rators Inited Nip- Com- apan. e size with men. ‘e the de- Pp up "Itage s Its aT mm the a large ity re- 2 water an un- t below es with p. The nforced water- tunnels e wells nel sys- ies en- ut two s of the ese two

January, 1925 House Cut in Half to Make Two Dwellings “DIVIDED household” accurately describes a family in Atlanta, Ga., which recently had its large house split into two parts. While the division was taking place, domestic duties were carried on with difficulty. The family ate breakfast in the north half, but before noon the gas and water in that side were out of commission, so they had to dine in the south side. The house was a large building with stucco finish, which caused difficulty in breaking it neatly. By skilful carpentry the structure was sawed clear through the middle, from roof to basement. The left half will remain on its present foundations, while the right half is moved several hundred feet. The raw

Two sections of the divided house faces of the two sections will be remodeled and rebuilt in symmetry with the whole, to produce two complete and attractive homes. Magnet Machine Picks out Clinkers; Saves Coal JLECTROMAGNETS of great power are used in new types of fuel-saving machinery to pick the clinkers out of the unburned coal. Successful tests of these machines recently were completed under the supervision of the U. S. Bureau of Mines. The principle underlying the new type of clinker separator depends on two simple facts: first, that clinkers and coal do not fuse and, second, that practically all clinkers contain a little iron and are therefore weakly magnetic. The new machines pass crushed furnace wastes under electromagnetic drums, which lift out the magnetic clinker particles and permit the non-magnetic coal to pass on, to be returned to the bins. Savings well worth figuring may be effected by salvaging unburned coal from furnace wastes, government experts say. One well known combustion engineer estimates that the average amount of combustible in the refuse from a large stoker-fired boiler plant is about 15 or 20 per cent.

POPULAR SCIENCE MONTHLY

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World’s Speediest Grain Elevator ‘THE city of Baltimore, Md., is about to set in operation what is claimed to be the fastest grain elevator in the world, in- corporating many new and interesting features. Only eight minutes will be re- quired to unload a car of grain, and only six minutes more to weigh the grain and transfer it to storage bins or to waiting ships into which it can be reloaded at the rate of 150,000 bushels an hour. Through the use of electrical signals and controls, only 77 men will be re- quired to run the plant. One man may control the loading of eight vessels simultaneously, the grain being carried out on belt conveyors. The new elevator cost $5,500,000. Its storage capacity is 4,000,000 bushels and there is provision for erection of storage

The top illustration shows pier from which four ships may be loaded at once, and the lower shows the new grain elevator tanks capable of handling 6,000,000 bushels more. The accompanying pho- tographs show the concrete storage bins or tanks with a capacity of 4,000,000 bushels, and one of the new piers from which four ships can be loaded at one time. The belt conveyors run overhead in the inclosed galleries, carrying the grain directly from the storage tanks to the end of the pier, where it is loaded into the ships.

New Tractor Excavator Sets Speed Record | HEN a new excavating device re- cently invented by a Californian was given its first practical test, it proved its merit by breaking all speed records for rapid removal of earth. The task con- sisted in excavating a sump hole or reservoir, 80 feet long, 40 feet wide, and approximately seven feet deep, near an oil well at Ventura, Calif. One man and a tractor, together with the patented excavating scoop completed the job in 40 hours, a task which would have required 10 days’ work for 10 men and 16 horses. The principal feature of the de- vice is the manner in which it is hitched to the tractor. Bya single controlling handle, the tractor operator, without

can load the scoop with earth, transport it to any desired spot without spilling its contents, and dump the dirt there. This ¢ excavator can dig square corners im- possible to excavate with horse-drawn graders. During the 40 hours which the excavat- ing required, the machine made 1800 trips and removed 900 cubic yards of earth.

leaving his seat,

The new excavating scoop, showing attachment to tractor, and controls

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POPULAR SCIENCE MONTHLY ¥ ge i oie oa a tess * & & co a -_ ea E ALL make beasts work for us, but the Japanese go one better. They force birds to help swell the family bank account. They have taught cormorants to fish for them. Rings around the necks of the birds prevent them from swallow- Japanese Make the Birds Fish for Tian ing the fish that they catch in the sea glades and the Tama River near Tokio. The fishermen, sitting at ease in their boats, control the movements of the birds by leashes, which they hold in their hands. Bicycle-Boat Skims Waves at High Speed Sysop the principles of speed boat and bicycle, an Englishman, George R. Stevenson, has invented a foot-propelled water bicycle that is said to be very successful and to attain high speed. The device consists of the usual [bie 8 The water-cycle and its builder bicycle frame with three pontoons, one on the end of the front fork, and one at each side of where the rear wheel ordi- narily would be. Motive power is supplied from the pedals through gears and a propeller shaft, the pedals driving a small pro- peller located at the rear end of the shaft. The shaft runs through and is sup- ported by a projection of the frame in the rear. Each of the rear floats that sup- port most of the weight is five feet long, one-foot beam, and eight inches draft, while the front member is four feet six inches long with the same beam and draft. The front float is pivoted so that it will ride over waves instead of bucking through them, thus tending to keep the bicycle-boat on an even keel in rough water. The machine is said to have towed a 16-foot dinghy carrying six persons. January, 1925 World’s Largest Crystal Spheres on Exhibition HE two largest flawless crystal spheres in the world recently were exhibited at a large department store in New York City. One of them measures nine inches in diameter and the other just fifteen-sixteenths of an inch less, Their weights are 500 Troy ounces 13 pennyweights, and 493 Troy ounces 17 pennyweights, respectively. The value of the pair is placed at $50,000. The spheres were brought to New York from China, where they were cut from a perfect Burma crystal with a Ae : ote = fea i d : 4 al EMPEROR EMPRESS The two largest crystal spheres small metal hatchet. The work required infinite patience. This fascinating crystal substance always has held a charm for people of all ages. In the Far East and in Europe in ancient times it was supposed to be ice in permanent form. In Japan small crystals were said to be the breath of the Great White Dragon, while the larger ones were supposed to come from the Violet Dragon. The crystal is emblematical of purity, in- finity of space, patience, and persever- ance. A Practice Putting Green on the Carpet As A means of keeping up one’s golf putting ability during the winter months and to af- ford a_ practice device that may be used anywhere, a putting board re- cently was devised. This consists of a cast aluminum plate that has a regulation size putting hole in its center. It rests on the floor at an angle from 15 to 25 degrees. At the top is a trough for catching balls that miss their mark. When the ball is **sunk” in the hole, another trough turns it out. The ‘‘green’’ though corrugated rubber matting is said to be preferable to insure accuracy. may be of any floor covering, al- An indoor putting match, showing the artificial inclined ‘‘green’”’ Janu recel Ti leng than The sign, tow!

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ry, 1925 tal on crystal y were tore in 2asures » other h_ less, ices 13 ces 17 - value » New sre cut with a } equired bstance le of all rope in e ice in d to be dragon, osed to . The ty, in- 2rsever- r is said curacy. reen”’ January, 1925 Huge Electric Sign Has Letters 50 Feet Tall OUR thousand lamps are required to F illuminate a gigantic electric sign recently erected in Philadelphia, Pa. The sign is 250 feet long, nearly the length of a city block, and weighs more than 50 tons. The letters are 50 feet high. The power required to illuminate the sign, it is said, would supply light for a town of 6000 people. One of the sign’s 50-foot letters POPULAR SCIENCE MONTHLY © Keystone Children “Go Motoring” in Bicycle Trailer A HANDLE-BAR seat may be all right, but two small children in Winthrop, Mass., have something better —a bicycle trailer, which they consider the latest in comfort and luxury. Their friend, Harry V. Grandin, hitched a pair Cold Baths in Lake Depths Fatal to Fishes —— may die from a cold bath, according to a report made by Prof. ; Frank Smith of the Zoology Department of the University of Illinois to the U. S. Bureau of Fisheries. This conclusion was based on a series of experiments with fishes in water of varying temperatures. Professor Smith conducted his studies at Douglas Lake in the northern part of Michigan. There are a number of deep ‘ places in this lake where the water does not circulate and therefore becomes much colder than the layers of water immedi- ately above, so that the thermometer will show a drop of several degrees in two or three feet. Fishes of several species, lowered to varying depths in wire cages, remained alive if kept above the cold depths, but died if they were left in the region of low temperature. Chemical analyses of the water showed that there was much less oxygen dissolved in the cold water than in the warmer layers, and also that other chemical conditions at the lower level were unfavorable to life. The “Tigon”’—Latest Oddity in the Zoo EET the “‘tigon,” a new member of the animal kingdom. With a lion- ess for a mother and a tiger for a father, this new arrival at the London Zoo bl His mother was a lioness and his father was a tiger shows resemblance to both. It takes after its mother for the greater part, but tiger stripes can be seen on his shoulders and legs, though not strongly marked. When it first arrived in London from India, the animal was called a Ciiger,” im the belief that its mother was a ti- gress and its father a lion. It was bred and presented to the zoo by the Maharajah. of Nawanagar, bet- ter known as Ran- jitsinghi, the cricket player. The Maharajah is said to possess more millions than he ever can count, and he delights in discovering curios- ities and making them known to the world. of wheels to the back of his bicycle, then asked them to take a ride. The construction of the “‘turnout” is so simple that any father could make one for his children. All he needs is willingness to provide the man-power to run it. Somersaults 900 Miles MAY a queer thing has been done to win a wager, but few as odd as that chosen to be performed by a Dutchman named Takkenberg, who is traveling from Amsterdam, Holland, to Marseilles, France, a distance of 900 miles, by somersaults. Takkenberg has completed a large part of his journey, which began on November 12, 1923, and must be com- pleted by February 12, 1925. He covers from three to four miles a day. The Dutchman calculates about 2,000,000 somersaults will cover the journey.

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Elevator Serves Hilltop Community With an opportunity to divide a beautiful hilltop into residence lots, providing he could make them accessible, an enterprising property owner of Hollywood, Calif., constructed the outdoor community elevator pictured above. A tunnel into the hill gives access to the base of the shaft, where an automatic electric elevator carries passengers to the hilltop —a distance of about 75 feet. Near the top of the tower a door leads to a walk connecting with the hilltop street, as shown at the left. Above the door- way is an observation room in the tower. Near the tunnel entrance is a group of garages, seen at the right, one for each home

64 POPULAR SCIENCE MONTHLY yOdd Things People Are A Community Elevator—Italy’s Super-Skyscraper—} Guaranteed to keep small children from crying while having their hair cut, this automobile chair re- cently was installed in a barber shop in Mt. Carmel, Pa. For the From Nova Scotia to Rome in a Canoe Paddling 1350 miles down the Atlantic coast from Nova Scotia, L George H. G. Smith, of Toronto, Canada, recently entered New York Harbor in his 15-foot canoe, completing the first leg of a contemplated voyage from America to Italy, traveling at 30 miles.a day. To fulfilla wager, Smith is on his way to Rome to call on the Pope, the entire journey, with the exception of crossing the Atlantic by steamer, to be made in a canoe An Auto Barber Chair January, 193

~<a thrill of being allowed to steer the car and toot the horn, who wouldn’t submit to the barber’s clippers? The : idea originated with , Harry Phillips. The ‘ little automobile can be swung in a circle and raised or lowered

oo, A Replica of Hudson’s Ship Celebrating the 315th anniversary of Henry Hudson’s landing in New York, an exact replica of Hudson’s boat, the Half Moon, with the explorer and his crew of 20 on board, sailed up the Hudson River recently and made a landing in the presence of thousands of cheering spec- tators. In the larger photograph Hud- son and his men are seen just before lowering the gangplank. Reginald P. Bolton, shown in the round photograph, took the part of the hardy English ex- plorer in the pageant. When Hudson went up the great river that now bears his name, in the Half Moon, he was looking for a northwest passage from Europe to China, but turned back on reaching the point where Albany vow is

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iuary, 1995 Tre er— g allowed - car and orn, who mit to the yers? The ted with ps. The obile can 1 a circle r lowered s Ship ersary of ew York, boat, the r and his 1e Hudson ing in the ring spec- aph Hud- ist before ginald P. otograph, nglish ex- 1 Hudson 10w bears » he was age from back on 1y DOW is Doing and Making January, 1925 POPULAR SCIENCE MONTHLY 65 The Largest Boot—Walking on Wheels A Six-Foot Boot Here, at last, is an ap- proach to one of the seven-league boots of fairy lore—a _ giant boot six feet tall, recently dis- played at a shoe and leather exhibition. The old woman and her family really could have got into this leather house. - Three babies could go to sleep in its toe alone. Beside this huge specimen are four of the smallest shoes ever made, with a pair of rubbers to match. Hours of painstaking workman- ship were required to pro- duce the little shoes, which are exact replicas of those of ordinary size sa Sis ted He Walks on Wheels Walking on wheels saves energy and gives all the pleasure of skating, according to a Swiss engineer who fits wheels to his shoes when go- ing-to work, as pictured above. -. The’ skates are fastened to the sien . shoes with t ee. ; HN ‘clamps’ and . a SS = braced”: by rigid anklets SP pw ene cect 08 ees ie gener about: nd aereene came ome oes mapecnce aan smote a Oregon Man Strikes Gold in His Back Yard Fee dei Italian Skyscraper to Overtop Woolworth Building America will lose one point of distinction when the world’s tallest skyscraper is completed in Rome, Italy. This building will have 88 _ stories and will be 1100 feet high—308 feet higher than the 51-story Woolworth Building in New York City. It will be used as a great community center. It will have 4500 rooms, 100 halls, a huge theater, a concert hall, gymnasium, swimming-pool, and libraries ‘ # Se This photograph might be used to illustrate the old story that ‘ teaches that the pot of gold en ; lies near at home. The hero, who lives at é ” Grant’s Pass, Ore., went out in his back Invents ‘‘Love Comb yard one morning recently and discovered The latest fashion in hair adorn- gold. In the picture he is seen examining ment is the “love comb,” carved the riffles in which the tiny specks of gold elaborately by hand in wood and accumulate. If this story has any moral, painted to represent love scenes it is not that we should all dig up our from famous plays. The inventor is back yards, but rather, that it might pay Miss Lettice Apperley, 18 years old us to move our belongings to Grant’s Pass

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66 POPULAR SCIENCE MONTHLY Cigarettes Now Are Sold in Slot Machines Sot machines for matches and candy and other items are a familiar sight in America, but slot machines for small boxes of cigarettes proved quite a curi- One Golf Club Replaces Usual Heavy Bagful O ELIMINATE the burden of carry- ing a heavy and unwieldy bagful of golf clubs, F. E. Ganders, of Walla Walla, Wash., has invented a universal golf club with which he says the whole game may be played as expertly as when the usual set of clubs is carried. The new device resembles a midiron, but the blade may be swung into any position, instantly converting it into a driver, mashie, putter, etc. This is made Driver, mashie, niblick and putter clubhead possible by a V-toothed sleeve on which the blade is mounted. This operates on two gear-shaped members that are inside the sleeve. To set the blade at any one of its various positions it is necessary merely to pull back the sleeve so that the gears may be set as desired. Releasing the sleeve locks the blade automatically. A Museum of Buttons N PRAGUE, capital of Czecho-Slo- vakia, is a button museum in which, it is said, every type of button ever manu- factured is displayed. The museum is the only one of its kind in the world. Some of the buttons date back 3000 years B.c. osity to a party of United States sailors in London not long ago. Several different varieties are offered so that all tastes may be met. A coin in the American sailors buying their cigarettes from English slot machine slot and a turn of the knob quickly furnish whatever is wanted. Matches also are carried in the machines. These machines are particularly convenient to the smoker after the regular shops are closed. THIN sheet metal, used in making toy houses, now is being employed in Budapest, Hungary, in build- ing real dwellings. Four-room bunga- lows covered with metal veneer can be built in 24 hours, it is said. New Burglar Alarm Is of Simple Construction HEN a door or window, equipped with one of these new re- movable burglar- alarms, is moved by the stealthy burglar, a bell rings so loudly that he probably will be frightened away. The con- struction of the device is unusually simple, having no locks, bolts, nor wiring. It is eight Bell burglar alarm inches long and the complete apparatus weighs one pound. The burglar stop consists of a jack. When the upper arm is bent inward by opening the door, the button of a bell attached to the lower arm is pressed. The bell rings as long as the door is open. January, 1925 Disappearing Bag Handle Lessens Chance of Theft A HANDLE on a traveling bag is a standing invitation to thieves, says the inventor of a new loop bag handle that disappears at the owner’s will. Any one who has tried to carry a bulky traveling bag the handle of which has been broken off, appreciates the difficulty of the task. It slips and it slides and sometimes it falls. At least if there were two bags side by side, one with a handle and one without, there is little doubt which one a thief would choose to carry away. The loop handle is made of steel and folds inside the bag when not in use. The handles are made to fit any standard frame and can be put on in place of the regular loops by an adjustment that takes but a few minutes. False Teeth Made of Steel ROM the steel that once was used in making big guns, the Krupp works of Germany now are manufacturing single and double rows of enameled steel false teeth. At present eight -dentists are em- ployed in this new department, and it is reported that the steel teeth are becoming increasingly popular because of their durable construction. Rainproof Motorcycle Shed Is Collapsible SPECIAL ga- rage for the motorcycle is one of the latest novel- ties to come from Germany, where the motorcycle has replaced the auto- mobile in many cases because of its economy. The miniature garage is made of galvanized iron and is weather-, fire-, and burglar- proof. Protection from thieves is as- sured by special locks. Collapsible motorcycle garage is weather-, fire-, and burglar-proof Janv thi eng col res ele ani usi las

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lle ft is a says andle ulky 1 has culty ; and were andle loubt carry l and use. idard f the takes teel . ed in ‘ks of single false em- | it is ming their pion January, 1925 Bachelor’s Collar-Ironer Is Useful in Emergency Hé WENT to the dresser, but no clean collars were there. To meet this predicament, an all too common one, a device has been invented that will enable a man hurriedly to wash out a collar and iron it in a minute, with results like those obtained in the laundry. The washed collar is placed around an electrically heated cylindrical form and another heated form is placed over it. Collars can be more easily shaped by using this device, it is claimed, and will last longer than if ironed with a flatiron. New Dry Polish Replates Silver or Nickel ee saiee with a dry polish that comes in cake form, is the latest method of replating worn silver or nickel ware. The method does not involve the use of mercury or acids, usually employed, but is based on the principle of frictional electricity. The action of the dry powder is like that in an electric battery. The silver or nickel is in fine form as in an electric battery solution, and is deposited on the object being polished, when electricity is produced by rubbing. ‘sory shop and POPULAR SCIENCE MONTHLY 67 Baby-Carriage Speeded Up by Self-Starter USHING a baby-carriage is usually a joy, but sometimes, particularly if one lives in a hilly town, it is real labor. An English minister, the Rev. Percival Mackenzie, saw no good reason for using man or wo- man power for what could be ac- complished by ma- chinery. So he went to a second- hand motor-acces- procured an auto- mobile self-starter, which he attached to his baby’s car- riage. It is so geared that, while there is no danger of excessive speed on the level, the perambulator will climb a hill with ease. Any motor-car, whether for grand- Miniature Vacuum Cleaner a Boon to Travelers T THE end of a long motor trip, when his clothing is covered with dust, the mo- torist would best appreciate the value of a newly manufactured vacuum cleaner in- stalled in the auto- mobile and run by the car’s motor. The cleaner is good, also, for cleaning carpets and the upholstery of an inclosed car. Its equipment in- cludes 10 feet of rubber tubing, which is ample to reach all corners of the car. The dust is collected in the handle of the nozzle, and may be emptied at the end of each cleaning operation. The cleaner in use Automobile Engine Runs a Washing Machine O SAVE his wife the stren- uous exertion of a washday, an ener- getic New Jersey husband backed his car up to the washing machine, jacked up one rear wheel until it came in contact with the drive wheel of the washer, andstarted the engine. The result was a motor-driven washing machine in which a friction drive was substi- tuted for gears or How the automobile engine was hitched to the washing machine belts. father or baby, must have a license. Observe the white label containing the number of this vehicle at the upper center of the carriage body. ©OK.&H. The self-starter is hung on a frame under the baby-carriage Less than 50 years after Edison pro- duced the first practical model, more than 350,000,000 incandescent electric lamps now are in use in the United States. The annual demand is more than 200,- 000,000. : Electric Lawn-Trimmer Saves Back-Bending Cr of the latest garden conveniences is an electric lawn-trimmer. The machine was invented by T. W. Martin, of North Hibbing, Minn., and consists of PP ud i ws. New lawn-trimmer equipped with motor a device similar to a hedge-trimmer, mounted on two wheels and run by an electric motor. Power for the motor is supplied from the regular house current by means of a cord, sufficiently long to enable the machine to be used at any corner of the lawn. Increased speed and greater con- venience are claimed for the device.

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POPULAR SCIENCE MONTHLY January, 1925 A SMALL army of workmen was re- quired to hoist into position the giant hands of the largest clock in the world, installed on top of a factory in Jersey City, N. J. The minute hand alone weighs a ton, and is more than 27 feet long. Minute Hand of the World’s Largest Clock Weighs a Ton In place of numerals on the clock face, which is 50 feet in diameter, there are great oblong blocks, black in the day- time, which flash with electric lights at night. By means of the lights the time can be ascertained by a person across the Hud- son River from the factory—more than a mile away. Two freight cars were required to transport this unique timepiece from the factory in Connecticut, where it was made. The photograph, showing work- men sitting on the minute and hour hands, gives an idea of the Alex, at 70, Tosses a Sapling N SCOTLAND, athletes contest at sports worthy of the great clansmen re- nowned in legend, history, and song. Alexander MacIntosh, an athlete well in his seventies, is shown tossing the caber, a sort of young telephone pole. Those who think this feat simple should get a good- sized sapling and try a few tosses to see how far they can throw it. , Mountain of Shells F YOU ever have won- dered what becomes of all the oyster shells, this picture will furnish part of the answer. It shows a mountain of shells at one of the world’s greatest oyster ports in Baltimore, Md. Most of the shells are finely ground and converted into chicken feed. Climbing a mountain of oyster shelis Alexander MacIntosh, 70-year-old Scotch athlete, tossing the caber Would Build Steel Homes in a Few Hours REMARKABLE solution to Great Britain’s housing problem recently was offered by Lord Weir, prominent Glasgow iron and steel manufacturer, in the form of mass production of standard- ized steel houses which, he declares, can be erected in a few hours. To demonstrate the practicability of his proposal, Lord Weir has erected near his factories in Glasgow a workingman’s three-room house of steel which, he says, can be built under the mass-production plan, for $1500, exclusive of the cost of the land and sewerage. He adds that after the concrete foundations are com- pleted, the house can be erected in a day. Standardization, according to the plan, will meet the shortage of skilled labor. Even the piping will be made in standard lengths and screwed together instead of being soldered. The framework of the experimental house is of wood, to which are bolted steel plates. All the factory-produced pieces are numbered for ease in assembly. Between exterior and interior sheets of steel is a felt lining for insulation purposes. The outside steel shell is painted, while the interior steel walls are lined with beaver board. The roofing is fireproof. astonishing size of this New Jersey landmark. Primitive Japanese Water- Wheel AU day long, with the hot sun beating down upon his head, the Japanese boy pictured below turns the paddles of a primitive water wheel with his feet, diverting water from the main irriga- tion canals into the ricefields. The wheel is placed at right angles to the main canal, and the turning of the paddles laps some of the water into the side ditch. While Japan is one of the most modern of countries in some respects, in others she is most primitive. Japanese farmers still use the implements most favored by their great-grandfathers. It hardly seems possible that in this age of electricity, manpower should be employed in such an arduous task as turning this water-wheel. Japanese boy turning a treadwheel

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ary, 1925 > thana ired to rom the it was g work- id hour , of the lis New anese el ith the x down apanese irns the e water iverting . irriga- cefields. at right nal, and paddles ter into 2 of the itries in ers she ers still by their seems ctricity, such an r-wheel. January. 1925 POPULAR SCIENCE MONTHLY AS THE first rays of the rising sun come to change the chill of a desert night into the heat of a burning day, this long line of camels is seen on the shifting dunes of the Sahara. It is the Egyptian Camel Corps, the terror, throughout the country, of all bands of outlaws. The eo cenon Carnal Corps—a Terror to ‘Guilawe of tad Desert Vast as the desert is, one might suppose that here it would be easy for a caravan robber to flee to. where he could not be followed. But the Camel Corps of native Egyptians, officered by British, know all of the secret hiding-places in the great wilderness of sand. As in the case of the Canadian Northwest Mounted and our own State Constabulary, it sometimes takes weeks of searching, but few are the criminals who ultimately, are not dragged back to face the law. Notice the long shadows cast on the sands by camels and riders. Three Hens Hatch Eagle’s Egg D Bee egg of a golden eagle, taken near San Diego, Calif., by Guy O. Glazier, of the San Diego Society of Natural History, required the services of three ‘‘biddies”’ to incubate it. When the pa- tience of one hen was ex- hausted, Mr. Glazier put an- other on the job. It was 41 days before the eaglet pipped the shell. A Face in Rock OMETIMES we have to tax our imaginations to see odd resemblances to ani- mals and human beings in rocks that enthusiastic guides point out to us. But any one would see instantly the remark- able resemblance to a man’s face in this natural rock formation at San Carlos Pass, Calif. This rock is similar to the celebrated formation in the White Mountains in New Hampshire, which is known as ‘‘ The Great Stone Face.”’ The rock face at San Carlos Pass Boctsnad by a Frenchman, this flying machine resembles a huge insect ‘Odd Manpower Airplane Flaps Its Wings A STRANGE flying machine, powered by the arms and legs of the operator and resembling an enormous insect, has been designed by a French inventor. It weighs 100 pounds and has a wing surface of 300 square feet. Above two wings, arranged like those of a bird, is a fore and aft fixed flying sur- face. Other smaller fixed surfaces curve out from the lower part of the machine. The two wings are flapped leisurely by the flyer’s arms. The machine is mounted on a bicycle, which is steadied by two small additional wheels. Pedals drive the propeller at 400 revolutions a minute. Big Tree for Chinese Junk Ts big stick of the year shipped from the Pacific Northwest lumbering region was 137 feet long and 42 inches in diameter at the butt. On an order from a shipbuilder in Shanghai, the tree was selected after a search of three weeks. It is to be stepped as a mast in a large Chinese junk plying the Eastern seas. The stick weighs 19 tons. On a board basis it contains 12,618 feet—which would be sufficient wood to build a good sized house. Cottage Is Finished in Seashells GRAseenee usually are considered beautiful but unsubstantial articles. It remained for an Englishman to demonstrate that they can serve as a unique and durable building material when ‘used in the proper manner. The photograph below shows the first seashell cot- tage, built on the English coast near Hunstanton. The entire surface of the exterior is set solidly with all kinds of seashells of many colors, picked up from surrounding shores and set in a cement composition. The result was a brilliant and most unusual stucco in which any number of designs could be incorporated at will. For cheapness and attractiveness the dwelling makes an ideal small cottage for the seashore, its builder declares. It has become a show place. Seashore cottage with shell exterior

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Rubber-Tire Steering Wheel Offers a Firm Grip NE of the useful new accessories de- signed for the comfort of the motor- ist is a rubber tire that is slipped over the steering wheel. It is said to make driving more pleasant by affording a sure grip for the hands; also, because rubber is a poor conductor of heat, it is less likely to make the driver’s hands cold and numb in winter weather. The device is a miniature tire and is easily slipped over the rim of the wheel. The elasticity of the rubber keeps it firm all around, and prevents its slipping, while ‘the ‘“‘tread”’ provides an effective grip for the driver’s hands. POPULAR SCIENCE MONTHLY January, 1925 Auto Pulls Itself up for Repairs FOR doing away with the troublesome job of crawling under the car when- ever repairs, oiling, or greasing needs to be done, an ingenious self-raising plat- floor. The car is driven on, and when it reaches the end of the track, the power from the rear wheels raises the platform and the car to a height of six feet. This is done by a Platform and car elevated by power from the engine. At right: Treadmill mechanism form recently has been perfected for use in garages and repair shops. The device consists of a steel frame with raising mechanism. Whenina lowered position, two rails that serve as tracks for the car are level with the New Headlight Control for Night Driving \ a; a newly in- vented mounting for Ford head- lights it is pos- sible, simply by touching a lever under the steer- ing wheel, to tilt the lights so that they throw their full beams di- rectly on the pavement in front of the car, making night driving considerably easier for everybody concerned. The device consists of a special tilting bracket on which the lamps are mounted, — When thrown downward, headlight beams do not cast dazzling glare these brackets being connected under the hood with a small lever bolted to the steering post just under the steering wheel within easy reach of the driver’s hands. Water Pump Attachment for the Small Car How the new water circu- lation pump is installed in the cooling system of a Ford car i agen water circulation pump for Ford cars is said to insure a perfect supply of water for the cooling system at all times. It is easily attached to the cooling system within a few minutes, the regular Ford hose being used. No new holes are necessary and a strong supporting bracket is designed to do away with all vibration and rattling. By keeping the water system in perfect circulation, carbon deposits in the engine are said-to be lessened. A saving of alco- hol in winter also is claimed as one of the advantages of the invention. "THE Editor will be glad, wherever possible, to supply the names and addresses of manufacturers of devices mentioned in this issue of POPULAR SCIENCE MONTHLY. form of treadmill that is geared to a worm gear at each corner of the frame. The revolving car wheels move the treadmill, and the gears thus raise the car. It is lowered in the same way. ‘ Economy of space and elimination of an incline are the chief advantages claimed for the device, which can be used to advan- tage even in a small private garage. SYNTHETIC motor fuel made from lignite, coke, and water was tested for automo- bile use with successful results during the recent Liquid Fuel Congress in France. France has large deposits of lignite and turf, from which almost unlimited quan- tities of this new fuel might be produced. Handy Reaming Tool Makes Valve Seats Tight T°? ASSURE compression-tight valve seats when you do your own valve grinding, a new valve seat reamer will be found handy. The tool is said to cut rapidly, removing carbon deposits and other irregularities, at the same time fac- ing the seat perfectly at the proper angle. It is said a few turns will quickly cut a smooth, clean face on the seat, effecting a saving of time in grinding the valve itself. How the new valve-seat reamer is used as, a, a oT i> nts ee Leak ee oA a eae

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when ower form by a dmill toa each ame. g car

imed lvan- mite, omo- g the ance. e and yuan- uced. kes valve valve ill be » cut and > fac- ingle. cut a ing a itself. sed

January, 1925 POPULAR SCIENCE MONTHLY Motorists in 36 States Pay $50,000,000 Gas Taxes OTORISTS of 36 of the 48 states in the Union now are paying a tax of from one to three cents a gallon on the gasoline they use for fuel in their cars, 17 states having adopted bills author- izing a gasoline tax during recent sessions. Since in the states that levy a tax on gasoline about 6,000,000 cars are regis- tered, using at a conservative estimate 2,604,000,000 gallons of gasoline a year, about $50,000,000 will go to the trea- suries of the states every 12 months from

VERMONT wn N. DAKOTA st 1¢

Shaded portions show the 36 states that have gasoline taxes, and the rate in each case automobile owners, or more than eight dollars a year for each car. The only states that do not tax gaso.ine are Massachusetts, Rhode Island, New York, New Jersey, Ohio, Minnesota, Iowa, Missouri, Illinois, Michigan, Ne- braska, and Kansas. Michigan legislators passed a bill pro- viding for a two-cent tax, but the bill was vetoed by the governor. In Massachu- setts the legislature authorized a two-cent tax and the bill was signed by the gov- ernor; but a protest from the required number of citizens led to the suspension of the new law until the voters express their will in a referendum in 1925. Seven gasoline tax bills have been in- troduced in a single session of the Ohio legislature, but the question of imposing a tax has been referred to a special com- mittee for investigation. Minnesota has passed a law authorizing a constitutional amendment that will make possible the imposition of a gasoline tax in the future. The Arizona legislature sought to increase the present tax of one cent a gallon to three cents, but the bill was vetoed by the governor. The states that now levy the tax and their present rates, are shown in the shaded portions of the map.

Air Filter for Carburetor Saves Repair Bills A “PELT throat” for carburetors is said to keep practically every bit of dust and grit from entering the engine through the air intake. The air filter can be fitted over this intake in various ways, according to the make of car and type of carburetor, so that all the air consumed by the carburetor first passes through a series of thick felt pads. As the pads catch the grit the excess dirt shakes off through the bottom of the filter. The device is inclosed in a specially perforated outside shell drawn from sheet aluminum and is equipped with a flexible hose of galvanized steel. The device, it is claimed, also controls the temperature of the air, muffles car- buretor noises, and greatly reduces carbon deposits in the engine. It is said to pro- vide positive protection from gritty oil, which causes scored cylinders, burned-out bearings, and large repair bills.

How air filter is adjusted to carburetor Long, Trailing Loads gern trailing loads, always difficult for the truck-driver to manage, are handled with ease by a new Belgian trailer that has a side seat attached to the From this a second driver rear trucks.

Steered at Both Ends steers the rear end from the left-hand side of the load. The idea is similar to that employed on fire towers and ladder apparatus in modern fire departments, except that the seat is placed beside the load and slightly below it, instead of above it. The photograph at the left shows a truck with the new steerable trailer hauling a load of long tele- graph poles through the nar- row, tortuous, streets of a Bel- giantown. Notice the small boy tak-

A second driver at the rear trucks aids in steering the load ing a free ride.

Valve Adjustment Made Easy for Mahone as B* USING a newly invented valve- adjusting dial, any car-owner is said to be enabled to adjust his own valves— a job that the average mechanic often does wrong—and to have a motor that neither rattles, clanks nor pounds. Each notch on the knurled dial repre- sents one thousandth of an inch. Simply by turning this with the thumb and finger, the car-owner can make the finest adjust- ment. By keeping the valve clearance just right, he can save gas, increase power, get the highest motor efficiency, and save bills for replacing valves burnt out from improper adjustment. A gage is furnished with every set to show the correct valve clearance. The adjusters are available for 13 standard makes of cars.

Vie valeets adjddted by knurled dial

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a y Belt Holds Child Safely in Automobile Seat oo the baby is bouncing around on the seat beside her, threatening at any moment to fall, no mother can give her undivided attention to the steer- ing-wheel. To enable her to be a better driver, a belt has been invented that holds children from one to eight years of age in a comfortable position on the front seat of an automobile. It passes around the child’s shoulders and across the chest, then is fastened at the back to the seat. It can be clamped quickly or released from the front seat. The child is thus prevented from climb- ing out of the seat. Know Your Car eo sal rt your car is in con- tinual use or not, it should be cleaned at regular intervals. Cool water is best always, though cold water applied when the car itself is in a cold place may injure the varnish. Never wash the car in bright sunlight or turn the hose on the body directly or under pressure. The stream should be transformed into a spray or the nozzle removed. Use clean water and change it fre- quently. The top should be cleaned first with tepid water, using Castile soap if the dirt is thick, and drying with chamois skin. The body should be washed with the sponge dripping wet, allowing the excess water to run down the panels in order to loosen the dirt so that it will wash off more easily. If the mud is caked on to the finish, don’t try to rub or scrape it off. Let a slow stream of water run over it and soak it off. After this preliminary, a new sponge and clean water should be used for a second washing. The car should be dried by using a damp chamois skin which has been rinsed in clear water and wrung nearly dry. POPULAR SCIENCE MONTHLY H° water for shaving anywhere, any time, is the luxury available for the man who carries a new compact water heating set and shaving outfit in his traveling bag. The set consists of three pieces—a small spirit lamp, a can for extra fuel, and a cylindrical can that fits A Hot-Water Shaving Outfit for Travelers January, 1925 the lamp and in which the water is boiled, The water container, fitted with folding handles, is just large enough for the shaving-brush to be immersed. The whole outfit is very compact, the lamp and spirit container both folding up into the cylinder. —— The complete hot- water shaving out- fit is shown in use at the right: water container, spirit lamp, and fuel con- tainer all can be packed in the can, as. shown above New Anti-Glare Spectacles for the Motorist YE shades in spectacle form are the la- test in anti-glare shields for mo- torists. The eye- pieces in the up- per half of the frame are made of a semi-trans- parent unbreak- able material in green or amber, while the lower half is empty. IRON staircases in the library of the British Museum recently were given a coat of rust, by means of chemicals, to make them less slippery and so safe- guard employees. Red Best for Signals ED, the traditional danger signal, proved itself to be the most easily distinguished of all colors at a distance, in recent tests for visibility of traffic sig- nals conducted by the U. S. Bureau of Standards. Green came second, while blue ranked a poor third. Ordinary rail- road yellow lights, it was found, often are mistaken for orange or red. The observations were made at dis- tances of 600, 900, and 1250 feet. Automatic Jaws Catch Mail from Trains MAIL-CATCHING device for ex- changing first class mail matter to and from moving trains has been de- signed so that it works automatically without the attention of clerks while the mail is being transferred ‘‘on the fly.” It also does away with damage done to the mail when bags are thrown to the ground or under the wheels. The new device consists of mechan- ical jaws that take the place of the familiar iron hooks on the side of the mail car. Similar jaws are attached to a newly designed post beside the tracks. When mail is to be transferred from a moving the post is caught in like manner by the jaws on the car and immediately swung inside. ; The entire operation may be set in ad- vance without needing further attention from the clerks. train, the bag on the car is hung on its holder’ by means of a ring. In passing the mailing post the ring is caught by the jaws and the bag thus trans- ferred. A bag hung on Model of the ingeni- ous mail-catcher, showing how the bag is caught from a moving car by auto- matic jaws (above) and how the car picks up a bag in a similar manner (left) Jar ha: al thi CcO% pre ke SW am

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1925 led. ding the rhole and ) the f the ven a ils, to safe- signal, easily tance, fie sig- au of while y rail- en are it dis- by the swung in ad- tention ingeni- vatcher, the bag rom a y auto- (above) he car ag ina er (left) January, 1925 POPULAR SCIENCE MONTHLY Automatic Attachment Turns Music Pages HE troublesome task of turning the ¥ pages of a music score and thus in- terrupting the playing is done away with by a recently patented music-turner that may be adapted to either the piano or music stand. For the former, the device consists of a rack with turner attachment, consisting of a wire frame with clips that hold the page to be turned. This device is con- nected with an attachment under the The knee control attachment for turning pages at the piano is shown above. The diagram at the right explains the operation of the device when applied to a music stand. Clips on a wire frame are fastened to the page of music which is turned by pressing a pedal keyboard and operated by the player’s knee. The operating connection is made by means of cord and two pulleys fas- tened at the end of the piano. Pressure of the knee against the attach- ment pulls the cord. This pulls a music clamp, which turns the page. The apparatus may be used on a music stand by attaching the pedal to the base, and running the cord along the bottom of the rack. TOP VIEW OF CENTER PULLEY WIRE AND pac. f SWINGS OVER TO LEFT THE fact that diamonds cling to lubri- cating grease in water, while pebbles and semi-precious stones roll off, has been made the basis for a new machine called a “‘pulsator,”’ which picks diamonds out of material in which they cannot be seen by human eyes. Rubber Skin Saves Fruit A PRACTICAL new process for pre- 4+ serving tropical fruits, other than bananas and pineapples, so that they may be shipped long distances, recently has been discovered. The fruit, gathered a little before it is ripe, is smeared with a thin coating of rubber latex which, when coagulated, forms a protective skin. The process of ripening is slowed up, it is said, keeping the fruit in good condition. Headband Visor Designed for Tennis Players OR tennis enthusiasts and _ other sportsmen, an athletic visor headband has been designed to keep hair and per- spiration from the face. It con- sists of a broad elastic band that fits any size head, with a visor to protect the eyes from the sun. This visor. is lined underneath with green, which is restful to the eyes in the glare of the sun. Ten Children Can Ride on “Seesaw” Swing A NEW type of outdoor swing for children, known as the ‘“‘rock-a-bye”’ swing, is said to afford a great deal of amusement and exercise to the young- sters. Almost any one could build it. It consists of a plank capable of holding 10 children. The plank is suspended on iron hangers that allow it to swing back and forth. Bars at How the ‘‘seesaw”’ board is slung from pipe supports each side enable the children to stop or start the swing at will. A safety catch keeps the board from being swung too far for safety. The apparatus is made of galva- nized pipe so as to withstand the roughest treat- ment from the chil- dren and all kinds of weather. The pipe can be joined easily. 73 Small Charcoal Stove Can Be Carried in Auto NY food that may be broiled, boiled, or steamed can be prepared on this convenient new steel camp-stove, which burns charcoal for fuel. Its total height is only seven inches, so that it may be packed easily inthe automobile. Utensils for steaming and boiling are placed on top of the stove. A foot pump helps provide a draft to get a good blaze started. The metal case in which the stove is carried contains, also, a compartment for extra fuel. Five cents’ worth of charcoal is said to be sufficient to cook a good meal for six persons. After the meal the stove can be packed away quickly. How Much Do You Know about Science? "THE following 12 questions deal- ing with fundamental facts of science were selected from thou- sands. of queries that have come from our readers. How many of these facts do you know? Answer the questions to the best of your ability, then turn to page 149 and see how nearly you were right. A dozen more questions will be published in next month’s issue. 1. How does a submarine keep from turning over under water? - When does the heart rest? . Why does it not hurt to cut our hair or our finger-nails? . How many different chemical elements are there? Why is snow white? . What is the metric system? Why do wires have to be used to carry electricity? . How far is the farthest star? . Why can’t you skate on glass if it is smoother than ice? 10. Why do we know that the earth is not made of rock all the way through? 11. Why do hard lumps of clink- ers form in a furnace? 12. What is a magnet? SA oI oo orn eo

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74 POPULAR SCIENCE MONTHLY January, 1925 How I Lead the Greatest The Remarkable Story of a Physical Director Who Gets NY morniné at seven, if you tune in Station WOR at Newark, N. J., you will hear the voice of A. E. Bagley, physical di- rector of the Newark Y. M.C. A., leading the setting-up exercises of the most remarkable gym class in the world—an invisible radio class numbering anywhere from 50,000 to 500,000 persons. This is the story of how hedoes it, told in his own fascinating way, and containing many useful hints that you can apply for better health and greater happiness. By A. E. Bagley HERE was a song that was very popular during the war, especially in the training-camps. It repre- sented a sleepy doughboy paying his respects to the bugler whose call awakened him at dawn or there- abouts. Some day I’m going to murder the bugler; Some day they’re going to find him dead} I'll amputate his ‘‘Réveillé,”’ And step upon it heavily, And spend the rest of my life in bed! That’s the way the song ended. No doubt you remember it. Of course, it was a comic song. And yet I suspect that many per- sons who heard it, and not a few who sang it, took the sentiment it expressed more or less seriously. For there long has existed an opinion that the most cordially hated thing in the world is. an alarm clock; that the great majority of people would be supremely happy and perfectly contented if only they were per- mitted to stay in bed every day as long as they pleased. You can’t prove it by me! On the con- trary, I’m ready to raise my right hand and my voice and tell the whole listening world that people do not ‘‘hate to get up in the morning,” as the song I just quoted had it. They like to get up, and they do it cheerfully and willingly. I HAVE always had that opinion. Many years of conducting gym classes con- vinced me that the average person is by no means Jas lazy as is generally sup- posed. And how I know that I’m right is because about 50,000 entirely representa- tive Americans and not a few Canadians have told me so in the last few months. Moreover, those 50,000 practise what they preach, for they and at least double as many others, living between New Brunswick on the north and Georgia on the south, and central Ohio on the west and the Atlantic coast on the east, for almost half a year have been getting up at the stroke of seven every morning except Sunday to let me direct them in physical exercises over the radio. Mine is the world’s largest gymnasium class. Just how many members it has, I do not know. There are 50,000 anyway, ‘ because I have received letters from that many. At the WOR radio station in Newark, N. J., from which I conduct the exercises, it is estimated that letters ordinarily are received from less than 10 per cent of the listeners-in to any broad- cast feature. So there may be a half- million people who go through the exer- cises with me every day. I hope there are —I hope there are twice that many, even though the thought of two million arms being raised and a million bodies bent as I call the commands for the exercises into the microphone rather frightens me. For it is encouraging, gratifying and stimulating to know that even the 50,000 who have written to me are willing to Much of the phenomenal success of the morning radio exercises Mr. Bagley attributes to the piano accompaniment played by Fred Harnett, who is pictured here leave their beds earlier than was their custom and go through the exercises for the benefit of their health. PROPERLY enough, we start proceed- ings by ringing an alarm clock. It’s the biggest alarm clock we could find, and the sound of its bell, issuing from a loud- speaker, I’m told, is sufficient to awaken the soundest sleeper. The mother of a large family in Massachusetts wrote me: “T used to be at my wits’ end trying to get my husband and my boys and girls up in the morning. Now, though, I just get up and turn on the radio set. None of them is able to sleep after WOR’s alarm clock goes off!’ Then, after the conventional announce- ment from the studio, we start the fun, The exercises illustrated here were selected from those given by Mr. Bagley to his radio class, as a group suitable for keeping the aver- age person in health. Chest legs. and shoulder developer. 3 and 4—Exercise for thigh and 5—Thigh and leg flexion to relieve constipation. Waist reducer and body vitalizer 1 and 2— 6 and 7— Janu

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y, 1925 NF st ets s their ses for roceed- It’s the and the 1 loud- awaken er of a yte me: ying to 1d girls , L just None of 3 alarm 10uNnce- he fun, January, 1925 POPULAR SCIENCE MONTHLY 75 ym Classes in the World Thousands of Folks Up at 7 O'clock to Exercise by Radio for that’s exactly what I try to make the exercises. The one thing I want to avoid is having my “early birds’’ look on their morning exercises as a painful duty, for exercise, taken as a duty, loses half its beneficial effects. So, when I can, I tell a little joke, ‘or indulge in a 4 \ little nonsense to liven “The thought of thousands of arms being raised and thousands of bodies bent as I call commands for exercises into the micro- phone, rather frightens me,”’ Mr. Bagley confesses. Here he is at the microphone of Station WOR, leading the world’s greatest gym class to piano accompaniment things up. We use the studio props— “crickets’’ and other noise-making con- traptions—to represent creaking joints or splitting pajama legs while we’re doing bending exercises. The other morning I told the class I was going to carry the piano up to the studio roof so that the radio operator could do the exercises with us. With the aid of ‘‘glass crashes,” thumps on the floor, grunts, and a lively conversation which I conducted with an imaginary janitor who apparently ob- jected to my removing the piano, we man- aged to produce quite a convincing little comedy for our hearers’ benefit. Also, the exercises are all done to music. Fred Har- nett, a young Newark busi- ness mian, is my volunteer pianist, and his lively tunes supply in great part the ex- ; planation of why a. at least 50,000 peo- ple have . become convinced that it is easy to insure their physical health and have a good time simultaneously. I can’t take the space to describe the exercises we do. The little sketches that accompany this article probably will explain them adequately. Try some of them for a few mornings and see how 8—Chest and shoulder develop- side. 12—Body circumduction. The last two strengthen the waist muscles 9 er. 9—Back-leaning rest to strengthen abdomen and back. 10—Arm circles for developing abdomen and chest. forward bend with rotation to 11—Body much better it will make you feel! Tune in on usif you can. If not, whistle a tune, or sing one, or put a record on your talk- ing machine while you swing your arms or bend your legs. At all events, make your exercise play, and not work. HAT’S about all there is to my big gym class, except that twice a week I give a brief talk on various phases of diet and exercise—how they may be em- ployed, for example, to improve the digestion, to reduce or increase the weight, to cure round shoulders, flat chests, or flat feet. That last may be worth noting here, for most people, I believe, are of the opinion that there is no cure for flat feet; that the best that can be obtained is relief through arch supporters, or similar ap- pliances. This is far from being the case. If you have flat feet, you can correct them, as I’ve told my early birds, by simple exercises you can perform while you’re putting on or taking off your clothing. While you’re removing your collar, say, walk around your bed- room on the outer edges of your feet with your shoes off, or try to seize some round object—a tennis ball, for example, or the rung of a chair—by closing your foot around it. A few weeks of this, and, un- less yours is a particularly ag- gravated case of broken arches, you'll probably find the natural arch of your foot reappearing in a most astonish- ing way. BY let’s get back to the gym class. As I said before, I’ve received some 50,000 letters from my early birds. All of the letters I’ve read, many I’ve replied to. In the main, they have supplied the most interesting reading it was ever my good fortune to encounter. The writers have been rich and poor, young and old, men and women. They have ranged from the president of one of the largest public utility corporations in the country, who wrote me a week or so ago to thank me for having reduced his weight 10 pounds, to a boy of 10, who, just after the World Series, wanted to know if I could guaran- tee that exercising every morning would make him ‘‘as good a pitcher as Walter Johnson.” (Continued on page 148)

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76 How to Make Low-Loss Coils ' Easy and Efficient Ways to Do a Difficult Radio Job By Alfred P. Lane IVE cents’ worth of 20-penny nails, a piece of board, a No. 12 twist drill, and a supply of wire are all the supplies you need to make your own POPULAR SCIENCE MONTHLY end bent or a crochet needle will make this easy to do. It is possible now to pull the whole coil off the nails, but it is better to pull out the nails, one at a time, with a pair of pliers. Otherwise you will be almost sure to bend January, 1925 coil can be lifted from the remainder of them. The next step is to fasten the coi] permanently with silk thread. A good way to do this is to use a long needle and sew the thread back and forth, as shown in Fig. 4 at foot of page. The number of

low-loss coils. And such coils, of the basket-weave type, often will greatly im- prove a radio receiv- ing set. This is par- ticularly true if the coils now in your set are wound on heavy cores or if the wire- itself has been coated with shellac or other insulating compound. No fixed dimen- sions are required for low-loss coils to give the best results, and this lack of limitation in size helps the home

nails is not necessar- ily fixed at 15. You can use a larger ora smaller number, pro« vided you choose a number that will re- sult in the staggering of the turns of wire so that a symmetrical winding can be made, Also you do not have to stick to the for- mula, around two; skip two. Another way is to go around one and skip _ two. Figure 3_ illustrates the first turn by

constructor, for it is often desirable to make the coil of some special dimension to fit the design of the receiver you make. In starting the winding of a coil, first you must decide on the diameter, bearing in mind that as a rule it is not advisable to make the coil too small. OIL A in Fig. 1 was wound around 15 nails set in a circle four inches in diameter. The circle was drawn on a seven-eighth-inch board and 15 equally spaced holes were drilled with a No. 12 drill on the circumference of the circle. In drilling the holes, be careful to hold the drill in a vertical position; otherwise the nails, when pushed through the board, will slant. Nail diameters vary considerably, and since it is necessary to have them fit tightly in the holes, you probably will have to discard several nails out of a handful because they are so large that they cannot be pushed through the holes or so small that they wabble around. After you have fitted the nails in the board, you are ready to start winding. The rule may be stated simply: Around two; skip two. Figure 2 shows the first turn around the nails. Continue winding in the same fashion until you have the number of turns you need. Remember that basket- weave coils require more turns for the same wave- length range than ordinary coils because the _ basket- seit iécemeii weave design reduces the isehioats a AROUND ONE internal capacity of the coil. SKIP TWO SKIP TWO When the winding is fin- ished, make a turn around a nail with the wire and cut it off, being sure to leave enough on the end to make connections. Now tie the coil at a number of points with thread or string passed down and back through the openings in the coil. A short piece of wire with one Fig. 1. Three types of low-loss coils made by the basket-weave method

Fig. 3. Two ways of winding low-loss coils. The method at the left was employed in wind- ing coil A in Fig. 1 on 15 nails. The method at the right was used in winding coils B and C

. Ais wound wire. B is wound on 11 pegs with No. 18 t double-silk covered wire and C, on 22 on 15 pegs with No. 16 double silk-covered pegs with No. 22 double silk-covered wire

Fig. 2. How the nail pegs are arranged in the board. The picture shows the first turn of wire around 15 nails being completed the coil out of shape or scrape the insu- lation from the wire. After all but a few of the nails have been pulled out, you will find that the

Fig. 4. How the wires are bound together by silk thread sewed back and forth, these two methods. Col A in Fig. 1 was wound by the first method of No. 16 double silk- covered wire, while coils B and C were wound by the second method. The correct number of nails for one system of winding does not always work with the other, but it is a simple matter to draw the circle first on a piece of paper and go around the proposed number of nails with a pencil line, and you will quickly see whether the winding comes out right or not. Coil B was wound around 11 nails with No. 18 wire, while coil C was wound around 22 nails, using No. 22 wire. This last coil is plenty strong enough to use as an inductance with only a clamp to hold it in place. Aside from the fact that basket-weave coils have extremely low losses, they have other points of advantage. They are so rigid that it iseasy to make two coils, one larger than the other, and mount one inside the other as a radio-frequency transformer, or to arrange matters so that the smaller one can be rotated. The latter scheme will result in a variocoupler or variometer of high efficiency. SOLDERING taps to a basket-weave coil at al- most any point is easy, for the spacing of the wire is such that it is necessary only to scrape the insulation off where it is to be tapped. In constructing radio re- ceivers, the amateur these days is turning out work that rivals the professional job in mechanical efficiency. Yet in appearance the amateur set, as a rule, could be improved. An article on page 90 of The Home Workshop this month, tells how you can dress up your set to give it “‘style.’’ crisscross

~— - et eet A [os alt on alll <n aiieulll a TE «. an?) Tn. a a ee ae tro ete as Pf oH Oo ct = O° eo UW

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iry, 1925 Is nder of | the coil A good dle and ; shown yer of ecessar- 5. You ger ora er, PIO hoose a will re- aggering of wire metrical ye made, 10t have the for- id two; Another . around ip two. | lustrates urn by thods. 1 Fig. 1 und by ble silk- _C were d. The ystem of with the to draw aper and of nails - quickly mut right ails with s wound re. This to use as » to hold et-weave hey have 2y are so coils, one ount one requency rs so that d. The esult in a ometer of aps to a oil at al- easy, for 2 wire is ssary only lation off ipped. radio re- sur these sut work »fessional »fficiency. ur set, as in article shop this is up your January, 1925 POPULAR SCIENCE MONTHLY Will Super-Power Replace Super Receiving Sets? Three new plans for developing broadcast transmission—W hat the new year promises you in radio progress By Jack Binns America’s most popular writer on radio HAT is going to happen in radio during 1925? Nearly every fan has been asking this question; for he wants to know just what kind of a set to buy or build, what kind of broadcasting will be on the air, and what kind of reception he may expect. During the past three years, radio development has been largely in the realm of reception, along the lines of improving receiving equipment. Now every indication points to a reversal of the order. Instead of more elaborate super- receivers to pick up and magnify weak signals, the trend is toward super-broad- casting with power increased so that dis- tant signals ean be brought in by even the simplest receivers. The development of transmission dur- ing the year will be along three well- defined lines, two of which will involve super-power. The third is national broadcasting through the interconnec- tion of broadcasting stations by means of telephone land wires. All three sys- tems will be experimental in character at first, proceeding according to recom- mendations of the recent Third Na- tional Radio Conference in Washing- ton, D. C. Thus, the use of super- power will be subject to immediate cancellation, should the fears of those who say it will tend to create a mo- nopoly of the air materialize. The three plans of transmission are so vital to every owner of a radio set, that I shall outline here what is con- templated in their development. Up to Fifty Kilowatts ‘THE first plan under the super- power scheme involves the erection of high-powered broadcasting stations - at points removed from any thickly populated area. Such stations will be connected with studios in the large cities by means of land-line wires. The Under the regulations laid down by the U. S. Department of Commerce, such a station may employ as high as 50 kilo- watts and will operate under an experi- mental license. This means that the license may be revoked at any moment How the future super-power broad- casting station may appear. The ~\ ve \ limit of power for broadcasting has ime \. beenone kilowatt. Now 50-kilowatt =) : eed stations are projected 2 WS. SSS: ‘ = —= ! te SS = = _s f “A ; first station of this character will be erected by the Radio Corporation of America at some point within 50 miles of New York City; not necessarily in New York State. Just what amount of power may be employed has not yet been decided definitely. A Wider Broadcast Wave Band Increase in the broadcast wave-length band to include waves up to 550 meters and down to 200 meters means that if you are planning to buy or build a new set, you should make sure it will tune in all broadcasting stations within these new limits. The purpose of the increased wave- band is to relieve congestion of. the ether. by the Secretary of Commerce should the operation of the station prove to be a source of interference with other existing forms of radio communication or broad- casting. The amount of power employed will be governed by the field strength of the signals at the nearest large city. The consensus of opinion expressed by the subcommittee at the confer- ence which determined the basis of the new regulations, is that this field strength should not be greater in the city than is the field strength of the present Class B station, one mile away. While no definite plan has been announced, it is under- stood that the Radio Corporation will ex- i periment with vari- ous degrees of power as soon as the new station is erected. In connection with the development of the super-power plan along these lines, should the experi- ment prove success- ful, the Radio Cor- poration intends to erect sim- ilar stations in other parts of the country, so that a com- plete national broadcasting system can be developed. Such super stations probably will be arranged so that all can be connected with a single program by means of radio relays. Many of the independent broad- casters also have announced their in- tention of experimenting with the super-power idea, and a plan has been formulated to interconnect these and at the same time develop an associa- tion for universal programs. High Power on Short Waves HE second system of super-power broadcasting involves the use of short waves far below the range of present-day receivers. This is the sys- tem that has been developed by the Westinghouse Company at KDKA in Pittsburgh, and KFKX in Hastings, Neb. The success of experiments already made have led to the belief that a considerable portion of the world can be linked to one program by means of this system without interfering in any way with the existing local broad- casting stations. The latest experiment was in con- nection with the Firpo- Wills fight when the newspaper la Nacional of Buenos Aires put in a special short-wave re- ceiver and reproduced the short-wave

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78 broadcast of the ring battle from KDKA. The short-wave transmissions of the latter station are received in England and rebroadcast in that country. It is understood that with this system, power as high as 100 kilowatts can be employed, making it possible to cover North and South POPULAR SCIENCE MONTHLY of Commerce Hoover by the Third Radio Conference. Under the new plan the country will be divided into six zones, instead of five, as at present. The material changes are that the northeastern Atlantic States will have stations operating on the same wave — ee Zone 3: 4: Southern central states. January, 1925 Northern central states. Zone Zone §: Rocky Mountain states. Zone 6: Pacific coast states. The new regulations are a_ recogni. tion of the fact that the tremendous jn- crease in the number of first class broad- casters during the America, Europe, and the Far East. Vast Network of Stations ‘THE third system is the inter-con- nection of all ex- isting broadcasting stations by means of a network of land- line telephone wires. The success of this system during the last year in broad- casting events of national impor- tance to all corners of the country is familiar to every radio fan. SCHENECTADY / past year has neces. sitated duplication of wave-length as- k signments on both coasts. Wave Changes HOSE fans who own receivers that permit “‘log- ging’ of dial set- tings will have to ™ hunt all over again ¥ as soon as the new’ wave length changes : go into effect. All broadcast stations } Be A, including — sta- tions originally assigned to 360 The National De- fense Day address of General Pershing, which was heard the length and breadth of the land, and the speech of President Coolidge on the eve of Election Day, when 25 broadcasting stations were joined as one, are striking examples of what may be achieved by a vast national network of broadcasting. A New Zoning System ANOTHER important development in broadcasting that will affect every radio fan during the coming year is the re-zoning of the country in accordance with recommendations made to Secretary The plan of re-zoning the United States for broadcasting, as recommended by the Third National Radio Conference. would be divided into six broadcast zones instead of five, as at present. Six Broadcast Zones instead of Five The country Some of the lengths as stations in Pacific Coast States. This can be done without interference because of the great distance between the stations and’also because there is a time difference of three hours between the two coasts. In the central portion of the country the zone division will be made between the north and south. The new broadcasting zones are: Zone 1: New England, New York City, and Schenectady. Zone 2: Atlantic coast, Metropolitan District to Florida. stations in the northeastern Atlantic States would have the same wave lengths as stations onthe Pacific Coast, thedistances between them preventing interference. Notice that Schenec- tady and New York City are included in Zone 1 meters, is to be abol- ished. All transmit- ters employing less than 100 watts in power will be put withinthewaveband between 200 and 240 meters. Stations us- ing between 100and 500 wattswillbe placed in the wave band of from 240to 280 meters. Stations using a power of 500 watts or more, formerly in the Class B category, will be assigned to waves ranging from 280 to 550 meters. The increase in the broadcast wave- length band to include waves down to 200 meters and up to 550 meters, means that the radio fan who is buying or building a new set should make sure that it will tune in all stations within these limits. Broadcasting Station on a Motor-Truck Makes Tests in Illinois AN ILLINOIS radio corporation re- cently has been eonducting ex- haustive transmission tests within a radius of 40 miles of sources of supply, for it carries its own generating plant, complete broadcasting and receiving equipment and collapsible mast and antenna. A gasoline engine operates a generator while the station is broadcasting so that transmission may be continuous. Chicago by means of a complete port- able broadcasting station mounted on a one-ton truck. The purpose of the! tests is to ascertain at- mospheric and broadcasting condi- tions and peculiari- ties of various local- ities in order to determine the best location for a per- manent broadcast- ing station of high power and _ wide range. The name of the portable station is WJAZ, with a wave length of 268 me- The set is of 100- watt power and it uses four 50-watt tubes. The entire truck is electrically lighted from its own power plant. The antenna mast reaches 53 feet, while the antenna consists of four heavily braided cop- per cables with ex- tremely fine wire. The entire frame- work and body of the truck are grounded at the side of the truck. Only 10 minutes are required to pack the outfit and have the truck under way after signing off ters. It is able to function without any external _re- Station WJAZ, a complete broadcasting plant on wheels. It supplies its own power from a program. will be reclassified. 7 The present Class > Janu: Moi stic rece has ‘ ‘Tt Set, Wil Nev hibi

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y, 1925 January, 1925 POPULAR SCIENCE MONTHLY 79 a adio in Its Oddest Forms oy Receivers Built into Farmyard, House, and Savings-Bank broad- ig the neces- ication th as- 1 both

. Zone ne §; Pacific

nges ns who ceivers “‘log- il set- ave to - again | 1e new hanges © t. All? tations ssified. © Class ©

x sta- | ¢ A three-tube regenerative receiver is nally Mounted on the end of a eS built into this picturesque rural scene. o 360 stick like a piece of The well at the extreme right forms ye abol- taffy, the little crystal the loudspeaker, while the small ani- ansmit- ee _— = has been aptly name a “The Lollipop Radio b t Set,” by its builder, . William L. Wray, of veband New York. It was ex- ~ 10NS us- hibited at a radio fair e placed meters. vatts or itegory, ig from mals, which can be turned on their pedestals, serve as the tuning dials. The builder is L. Abrams of Brooklyn, N, Y.

5 wave- n to 200 uns that Y ilding a V7 Y vill tune -Yyf Complete, even to the tiny aerial above the roof, this miniature cottage really is a crystal set. It was built by John Neis of Chicago, IIl. 1S - engine cation is on may us. ; of 100- - and it 50-watt e entire ctrically 1 its own t. The mast 3 feet, antenna of four ided cop- with ex- 1e wire. » frame- body of k are t the side k. minutes d to pack and have. nder way ning off gram.

One of the larg- . —_— est sets in the < — country, an 18- Lj b +t tube superhet- 4 erodyne, and its pi a builder, H. H. Elmer, of Syracuse, N. Y. He claims to have heard Mexico City, Rio de Janeiro, and other distant points. Note the glass paneled case

Here is one case where radio has been developed into a money-saver. The coin savings-bank with crystal set attached is one of the latest novelties. Above the circular nickel bank are the receiving instruments. The inventor is Tess - Christian of Mt. Lake Park, Md.

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A de Luxe Three-Tube Set- It’s So Simple By James S. Caulfield NE stage of tuned radio-frequency amplification, a regenerative de- tector, and one stage of audio- frequency amplification make a practical, com- mon-sense . broadcast receiver that is both sensitive to distant sig- nals and at the same time highly selective. The circuit includes no useless frills and an in- spection of the wiring diagram and the pho- tographs of the layout of parts will show that it is simple in design. Y SETTING the detector tickler coil D so that the detector circuit is oscillating, this receiver can be tuned by means of the carrier whistle, and yet it cannot radiate be- cause the _ radio-fre- quency tube prevents the oscillations from reaching the antenna. This method of tuning is quick and easy and is preferred by many radio fans. over the entire band of The stage of radio-frequency amplification was incorporated because it increases the strength of weak signals and also acts to prevent radiation. Tuned radio frequency is employed because it gives a fairly even degree of amplification POPULAR SCIENCE MONTHLY 1925 Model added to increase the volume of sound to operate a loudspeaker. The Layout of Parts Fig. 1. Rear view of the three-tube receiver, showing the layout of parts and wiring. The various parts are lettered to correspond with the letters used in the wiring diagram below and in the description of the set in the accom- panying article. At the right is a front view of the panel showing control dials and knobs is not needed. The receiver has been The neutralizing condenser H prevents the tube in the radio-frequency stage from oscillating. The conventional potentiom- eter often used in radio-frequency circuits designed with a sub-panel that permits concealed wiring. Sub-panel construction not only improves January, 1935 that Even the Beginner Can Build It Audio-frequency amplification has been the appearance of the receiver, but it algo reduces the time required to do the wiring, which is certainly an advantage. makes the wiring as direct as possible, thus reducing the length of the wires, And it The binding posts have been mounted on the rear of the sub-panel so that con- nections can be made through the back of the cabinet. standard 7-by-21-inch cabinet. The parts needed are as follows: The receiver will fit the A—input coil wave lengths. Other Vv 5 ee requemiy plate on F etector grid circuit coi types of radio-frequency Bue D—detector tickler coil amplification sometimes HY E and F—variable condensers, amplify much more at : Sc? Gail comtenene bes a one wave length than at (9) wy r () crofarad with clips for . grid leak any other. “ A ba B Ls M P S L H—neutralizing condenser, Regeneration was L = E be = F ua i N : approsiosately 0003 : : | 2 : microfara added to the circuit be- ; 6 P I, J, and K—standard sockets cause it increases the B lx [—i5-ohm rheostat sys ie f th d M—30-ohm rheostat sensitivity 0 e e- N—audio-frequency' trans- tector tube and at the | ri former ‘ « . . —gr : m ms same time improves the he P ele tek” sharpness of the tuning. = } z. = a ye panel, seven by r tickler coil = agg The detecto Fig. 2. The complete wiring diagram of o 7. R—sub-panel, seven by 20 D is used to cause regen- s O inches; seven binding 2 the three-tube set, with parts lettered to cor- DET AMP posts, three dials, brack- eration. | respond with those in the photograph above A BATT B BATT 90 ets, screws, etc. ae a ee acne, OS ac pees a eee eee hag en aera) Sat : 2 - ++ -+ 9 + | | “ ° \ >» | | 5 Tt %- a + + space For 5 i ADDITIONAL AMPLIFIER + a FOR BRACKET |} ALL HOLES DRILLED WITH N27 DPILL UNLESS OTHERWISE SPECIFIED : ry 1 ri +- -—— 7" ‘ Pig. 3. Layout of front panel, with measurements for drilling the holes Fig. 4. Layout of sub-panel. Binding posts are at rear Ja

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ary, 1925 {— ut it also 1€ wiring, And it possible, he wires, mounted that con- ie back of ll fit the Ws: r plate coil ircuit coil r coil condensers, clips for condenser, -000003 lard sockets a tat y trans negohms ck |, seven by ren by 20 en binding ials, brack- PLIFIER January, 1925 High grade parts should be purchased of any standard make so long as they will fit in the space provided for them. Note that the panel layout, Fig. 3, does not include the holes for the screws that are used to mount the condensers. No two makes of condensers have the same spac- ~ ing for the holes, and most manufacturers supply a paper templet so that it is neces- sary to know only the location of the hole for the shaft. HE first part to construct is the input coil A, which is shown at the right in the rear view, Fig. 1. The form for this coil is a bakelite tube, three inches in diameter and 334 inches long. The wind- irg consists of 60 turns of No. 22 double silk-covered wire. A tap should be made on this coil at the twelfth turn from the end that is to be connect- POPULAR SCIENCE MONTHLY the winding in this way to pro- vide space for the shaft on which this coil is mounted. The dimensions of these three coils and the details of the parts needed to mount them are given in Fig. 8. The panel and sub-panel are the next parts that must be prepared. These are parts Q and R and the layouts are given in Figs. 3 and 4, re- Fig. 5. . tion. ed with the ground. The tap is for the antenna binding-post conhection. After the coil is fin- ished, mount it on the rear of variable con- denser E, as shown in Figs. 1 and 6, and then lay it aside until you are ready to start mounting all the instruments. The next operation is to construct the special radio-frequency _ trans- former that consists of coils B, C, and D, as shown in the diagram, Fig. 8. Coil B is made by winding six turns of No. 20 double silk-covered wire on a bakelite tube 234 inches in diameter and 11% inches long. The wire on this coil should be spaced one- eighth inch between wu ole d Tuning In James S. Caulfield tuning in the set that he de- scribes in the accom- panying article. He begins by setting the dial controlling the tickler coil, to throw the set into oscilla- The tuning is completed by adjust- ing condenser dials run a branch to one terminal of the neutral- izing condenser H. The other side of condenser H connects with the tap on coil C. The plate terminal of socket J next is con- nected with one end of coil B, and the other terminal of coil B is con- nected with the ampli- fier plus B binding post and the wire continued around to one terminal of jack P. HE terminals of coil C now can be con- nected with the ter- minals of condenser F. turns. Coil C consists of 62 turns of No. 20 double silk-covered wire on a Figs. 6 and 7. » _yans H b> io Fate TURNS Yl 6 B g, TAP 16TH TURN | TICKLER ¥ ry 4 % VA PRIMARY pay THREAD ee ae Te 1% 44 DF Saas 532 How to Make the Coils Fig. 8. Diagram showing how to build the tickler coil D, the grid circuit coil C, and the radio-frequency plate coil B. Measurements for the rotor shafts are shown in the figures that will be seen at the bottom of the diagram bakelite tube three inches in diameter and four inches long. The winding should be started about half an inch from the right end, as shown in Fig. 8, and a tap made at the sixteenth turn. Coil D is made by winding 21 turns of No. 22 double silk-covered wire on each end of a tube two inches in diameter and 14% inches long. It is necessary to divide from each side. ing of input coil Layout of the set viewed At left note the mount- A at the rear of variable spectively. When you have finished them, it is well to fit the sub-panel to the panel and the panel to the cabinet you have selected for the receiver, for if the panel is a shade too large, it is much easier to file it down before the instruments are mounted on it. Note that there is suffi- cient space at the left end of the sub- panel, as shown in Figs. 1 and 7, to fit another stage of audio-frequency ampli- fication if desired. The brass brackets necessary to mount the-sub-panel can be obtained in any radio store. Fiche you are satisfied with the fit of the panel in the cabinet, proceed to mount the instruments as shown in Figs. 1, 6, and 7. Now for the wiring. Condenser EF is connected across the terminals of input coil A, with the rotary plates, with the ground terminal of the coil. The antenna binding post is connected with the tap on coil A. Now wire the filament circuits of the three sockets, J, J, and K, with the rheostats L and M and the A-battery binding posts, as shown in the wiring diagram, Fig. 2. Next, connect a wire from the grid of socket J with the stator plates of condenser E, and from this same wire condenser E. The mounting of detector grid circuit coil C and detector tickler coil D is shown in the right-hand view Be sure that the rotary plates are connected with the wire that is con- tinued to the filament circuit of socket J. The grid condenser G now can be con- nected between the stator platcs of con- denser F and the grid terminal of socket J. Make this connection just as short as possible. The grid condenser is supported by the wires leading from it. One terminal of coil D is connected with the plate terminal of socket J, and the other goes to the P terminal on trans- former N. The B terminal on trans- former N is next connected with the de- tector B binding post. This completes the wiring, with the exception of the sec- ondary circuit of the transformer N and the plate circuit of socket K. The G terminal should be connected with the grid terminal of socket K and the F terminal with the battery side of rheostat L. The last wire is that which connects the plate terminal of socket K with the remaining terminal of jack P. When the wiring has been completed and rechecked against Fig. 2, connect the antenna, the ground and the batteries. Insert tubes in the sockets, first making sure that the rheostats are on the “off” position. Now turn up the rheostats until the tubes are burning dimly. If squeals or whistles are obtained, adjust the neu- tralizing condenser until they disappear. (Continued on page 150)

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as 82 How to Do without Radio Batteries POPULAR SCIENCE MONTHLY January, 1925 Simple Ways to Run a Set from a Farm Lighting Plant By Alexander Senauke, M.E. HOUSANDS of American homes today are equipped with inde- pendent lighting plants that sup- ply a ready source of power with which the radio receiving set can be connected so as to eliminate the use of special A and B batteries. A number of different makes of farm lighting units are in use in various parts of the country, but all can be divided into two classes—those that use storage bat- teries and those that do not. The POLARITY units that ope- rate with storage le — TO LIGHTING OUTLETS AND FIXTURES RECEPTACLE AND PLUG or the rest of the cells may have to be overcharged too often to keep them up to voltage. Figure 2 illustrates another way of con- necting up that employs a resistance unit to overcome this objection. It is also easier to connect up, since no special wire has to be run all the way from the battery to the receiving set. The table at the bottom of this page gives the value of the fixed resistance that should be used with the hook-up shown RADIO SET Serre een ene TO GENERATOR batteries have been well standardized so far as voltage is concerned, so that the battery of practically every farm lighting unit develops either 32 volts or 110 volts. If your home is equipped with a 32-volt system, you can dispense with all extra batteries for your radio set if your re- ceiver uses only one tube. A multi-tube set, however, requires more than 32 volts, so that with such a set it still will be necessary to use one block of B battery to obtain the correct plate voltage for the amplifier tubes. With the 110-volt system, the voltage will be found ample for all requirements. Figure 1 shows one way to follow to hook up the receiving set to 45-VOLT B BATTERY (NOT NECESSARY ON NO-VOLT CIRCUITS) These diagrams show BS two different hook- 1 es ups for connecting a el a radio receiving set hi with either a 32- = volt or 110-volt farm See lighting storage bat- tery system. The one at the right uses a fixed resistance, the value of which can be determined ad ‘TO BATTERY by the table below RESISTANCE UNIT TO FIT * ° STANDARD in Fig. 2 to cut down SOCKET the voltage for the filament circuit when from one to five .06-ampere or quarter-ampere _ storage-bat- tery tubes are used on either 32 or 110 volts. If the battery is situated a considerable dis- tance from the receiving set, the resist- ances specified for 32-volt circuits may have to be cut down somewhat, owing to the drop in voltage over the line. There is one point that should be men- POLARITY PLUG (NOT NECESSARY ON II0-VOLT CIRCUITS) tioned in connection with the circuit of Fig. 2. Do not turn off or remove one tube from the socket while the current igs turned on, as this would throw an extra load on the other tubes and they might burn out. TORAGE batteries form a source of power supply for radio work that is ideal because the current flow is perfectly even and steady and the voltage drop is so slight between full charge and normal discharge that it does not affect the ad- justment of the filament or plate control, However, when the generator is running to charge the batteries of a farm lighting outfit, there usually is a slight hum, depending on the condition of the gene- rator brushes and the capacity of the bat- tery with relation to the charging rate of the generator. Most of the systems are automatic in operation so that the gene- rator starts charging when the battery voltage drops, indicating that a charge is necessary. If you are going to use a set employing several tubes that would amplify this hum enough to be troublesome, it will be worth while to have the service man from RADIO SET 45-VOLT B BATT. the company that supplied the outfit arrange a switch that will prevent the generator from starting when you are trying to receive. The switch should be placed handy to the radio receiver. Since most farm lighting out- either the 22-volt system or the 110-volt system. No con- nection is necessary to the minus B binding post, be- cause this post is connected inside the set with either the minus or plus A binding post and this connection is already made for you in the battery itself. There is one objection to this ve way of obtaining the filament current that applies particu- larly to multi-tube sets. The extra drain on the first three cells, if the receiver is used constantly, eventually may exhaust these three cells, What Fixed Resistance to Use HE following table, prepared by Alexander Senauke, expert of the PopuLar SciENcE IN- STITUTE of STANDARDs, shows the value of the fixed resistance that should be used with the hook-up in Fig. 2, according to the number and kind of tubes employed in the receiver and the voltage used: .06-Ampere Tubes 32 volts 110 volts 32 volts Quarter-Ampere Tubes 110 volts 1 450 ohms 1750 ohms 100 ohms 420 ohms ize:lU* Sve. * 55 .* 210 3156s lad a.UCS SS si‘ ia 4115 * 440 ‘§ a7 le ** | aS 5 90 * ed , 84 fits are so adjusted that the generator starts long. before the battery has reached the dis- charged condition, holding up the charge in this way for an hour or two will not cause any damage. The diagrams shown here can be applied to all forms of home lighting outfits except those that use a 110-volt batteries. In next month’s issue such outfits will be 66 covered in an article that ‘6 will show you how to use the 110-volt lighting current from the street mains to run your radio set. 6¢é 66 Senerator instead of storage’

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y, 1925 “$ uit of 7e one rent is extra might irce of that is rfectly lrop is 10rmal he ad- ontrol, unning ghting hum, > gene- ne bat- rate of ms are 2 gene- yattery charge sloying ly this will be n from ‘ig. 2 outfit ont the rou are should eceiver. ing out- hat the before | the dis- ding up y for an 1use any vn here orms of ; except 110-volt storage : nonth’s will ._ be le that to use current storun January. 1925 POPULAR SCIENCE MONTHLY 83 An Easy, New Way to Drill Panels Useful Ideas that Will Simplify the Hard Jobs in Radio By Robert E. Martin many anew radio fan tackles with fear and trembling. He feels confident of success so far as the small holes are concerned—those of, say, three-sixteenths of an inch or less; but the big holes present quite a problem. In the first place, big drills cost money, and in the second place the average fan usually does not own a drill brace that will hold drills larger than one-quar- ter of an inch. Yet there are a number of radio in- struments that require holes larger than this in order to fit them to the panel. I happened to be in a hardware store the other day when the proprietor was rearranging some of his stock. Among the pile of merchandise on the counter were some reamers. One long, thin box struck my eye. It was marked: “Taper—1l¢ to \% inch.” As I had gone into the store to buy some big drills to make the holes in a new panel, it oc- curred to me to see what that reamer would do in radio work, so I bought it at a cost of 80 cents—less than the cost of two sizes of the large drills. In Fig. 1 is shown the reamer in operation, as well as the result of an experiment on a particularly tough and brittle piece of bakelite. A row of holes was drilled with an ordinary one-eighth-inch twist drill and then the reamer was inserted in a bit brace and turned into the holes. It ate Dinere: the panel is a job that its way through as if the panel were just so much cheese—and quickly too. No chipped nor marred edges, holes were clean and smooth. It is true that each hole left by the and the Fig. 1. How a standard taper reamer may be used to drill any size hole, from one- eighth to one-half inch, in your radio panel, as shown in the radio panel below Fig. 2. An ordinary pencil eraser aids in close tuning. With the rubber pressed against the panel and the edge of the dial, the pencil is rotated, making minute changes ia the setting reamer has a slight taper to it, but not enough to make any difference for radio work. With one twist drill and this standard sized reamer, you are equipped to fit to a radio panel any instrument that does not require a hole larger than one-half inch. Just try this way of “drilling” the next panel you make. a) ¥ electric-light bulb to reduce the current to the proper value, and the 110-volt alter- nating current from the street mains. The peak voltage on each side of the cycle of 110-volt alternating current is in the neighborhood of 155 volts, so that it ought to be possible to charge batteries up to at least 120 volts by this system. But practically, it cannot be done because of the losses in the rectifier, produced by the high voltage applied to the rectifier when the direction of current is oppc- site to that which charges the battery. The charging system shown diagram- matically in Fig. 3, gets around this difficulty by the use of two rectifier cells so arranged that one side of the current wave charges one half of the battery, and when the current swings to the other direction, the second rectifier cell sends the current through the other section. To charge the battery it is necessary only to clip the wires on the battery as shown and close the double-pole switch. Be careful to connect the lead and aluminum plates as they are in the draw- ing, for if you get them reversed, the bat- tery will be charged in the wrong direction. The rectifier cells should be of one- 25-WATT LAMP For Close Tuning O YOU find it difficult to make those close adjustments of the dials that bring in the distant stations with maximum loudness? Here is a little kink that will give you practically as good results as micrometer dials at a cost of five cents. Use an ordinary lead pencil held as shown in TO HO-VOLT MAINS (ALTERNATING CURRENT) ALUMINUM PLATES Fig. 3. Dia- gram showing hook-up of a simple new method of charging batteries with alternat- Fig. 2, with the rubber pressed against the panel and the edge of the dial. When you rotate the pencil, the dial will turn slowly. In this way it is easily pos- sible to make changes in the setting so small that you can hardly see the dial move. This method is particularly valu- able for use on receivers that are troubled with capacity effect. The pencil keeps your hand a consider- able distance from the panel. Charging B Batteries ‘THE usual way to charge storage B batteries that develop not more than 50 or 60 volts is to place a single chemical rectifier cell in series with the battery, an ing current from 110-volt mains quart capacity and the aluminum plates should have an area exposed to the solu- tion of not more than one square inch. The size of the lead plates can vary from two to several square inches. The electric-light bulb should be the twenty-five-watt size. The solution to be used in the rectifier cells is borax dissolved in pure water until you have a saturated solution. When you have the rectifier completed, it is necessary to hook the three .clips together and allow the electric bulb to burn for about half an hour. This will form the plates and you then can hook the clips on the battery terminals as shown and charge the battery.

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84 POPULAR SCIENCE MONTHLY January, 1925 Twenty-One Inventions The Latest Household Suggestions in Pictures A new portable elec- Troublesome cords are tric ironing machine, eliminated by new elec- controlled by hand tric irons that are used levers, can be set out with an_ electrically of the way easily heated contact base when not in_ use Ss oY ae po ar a - Turning steaks or roasts is sim- plified by this triple-jointed double-pronged cooking fork The teakettle be- low is also a plate- warmer. It has anopening through which plates are placed over the water Te eae wire oven rack provides a convenient means of removing cooking food from the hot oven A labor-saving floor-waxer with long handle. Wax is applied through a cheesecloth cover This handy four -in-one kitchen implement serves to open cans, chip ice, open milk bottles and remove metal caps from _ bottles / From one to six eggs can be boiled at once in this wire basket, which folds to fit smaller vessels Placed over the gas flame, this A trapdoor on the Orange peel is removed in un- circular cooker catches drippings, ashcan cover pre- broken halves by a new curved concentrates the heat, saves pans, vents dust from fly- implement that cleanly sepa- and keeps the stove. clean ing all over the cellar rates the peel from the fruit cnn _ PM ee inne PARR ABs oe ke & = 2. oh D> fae

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1S ires ker with applied cover eggs can ce in this nich folds r vessels in- red pa- uit January, 1925 and How They Add to Every The vacuum cleaner is converted into a wash- ing machine for clothes or dishes by an agita- tor attachment fast- ened to the blower outlet of the cleaner POPULAR SCIENCE MONTHLY to Save Your Wife Work -Day Convenience Here is a compact new washing machine with large capacity. A_ sealed air space be- tween inside copper tub and outside covering holds the heat in. The machine has a swinging wringer at- tachment | Below. is a new baking-dish of special glass, with conicel center for Lorna Dcone cake Two kinds of food can be cooked at once in this two-sec- tion frying-pan yyy Rey \} Floors can be scrubbed and mopped in one operation with pp, this combination brush A wire cage for cut- ting bread into even slices for sandwiches. The knife is inserted between the wires A highly concentra- téd new gas in crys- talline form is con- tained in this new moth preventive A remarkable grinder with at- tachments for stuffing sausages, pressing fruit, and grinding meat A new method of preserving. Just before the glass jar top is clamped over a gummed ring, the air beneath is consumed by flame To prevent offensive cooking odors, and to do away with the heat of cooking, this cabinet has been designed to inclose the stove. A special ventilator built above the stove carries away the odors

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86 POPULAR SCIENCE MONTHLY January, 1925 Is Your Car in Trim for Winter? An expert’s practical hints on how to prepare it for freezing blasts, whether you drive it or store it By George A. Luers AM going to tell you about two | automobiles that I saw during the last year. The first was a smart coupé of expen- sive make. I came upon it one excep- tionally cold day on the main highway be- tween Washington and New York. The hood was up and two men were peering in at the engine. One I recognized as a well- known Washington professional man. The other was the proprietor of a gasoline station situated about a mile from the place where the car was standing. The car had run out of gas on the road, and its owner had walked to the filling station to replenish the supply. In the short time it had taken him to reach the station and to drive back with its owner, the engine This diagram shows im- portant points to safeguard against leaks in preparing your engine for anti-freeze compound: washing. Use sealing compound to repair slight leaks. Tighten clamps every C—Cylinder flange gaskets. Tighten and shellac. outlet hose. Renew if condition is doubtful. two to four weeks. shellac. D—Cylinder head gasket. Flange gasket. Tighten and shellac. Renew if necessary. Tighten clamps every two to four weeks. Packing nuts. Tighten every two to four weeks. Tighten and shellac. J—Pump hose. clamps every two to four weeks. had cooled down and frozen solid, burst- ing the cylinder block. This necessitated a long tow, extensive engine repairs, and loss of the use of the car for a couple of weeks. All because the owner had failed to use alcohol or other anti-freeze mixture in his radiator, assuming that he was secure from danger because he kept the car in a heated garage at night! HE other car I saw a few months later—on one of the first warm days of spring. It was in the garage of a friend of mine who lives in the suburbs of Wash- ington. He uses the car, a medium- priced one of popular make, only for pleasure, and had, so he said, ‘‘put it up for the winter.” That is to say, he had run it into his garage in the fall, opened the radiator petcock to drain the cooling system, and had gone out, locking the garage door behind him. A—Radiator. J—Radiator outlet. and repair large or small leaks with a reliable sealing compound For four months he had not so much as looked at the car, and when he tried to take it out, it refused to run. He asked me to run over and see what the trouble was, and the things I found the matter with that car were plenty! . The storage battery was cracked. The fan belt was broken. The four tires were flattened and weakened from _ supporting the weight of the car. The exposed steel parts of the engine and electrical system were liber- ally coated with rust. Now, these two Clean by B—Cylinder cold and moisture, is quite as bad ag going away on your vacation without locking your front door. Now, strange as it may seem, it is usually better for your car, and it may be cheaper, to keep it in operation all winter than to lay it up. Outside of a slightly larger consumption of gasoline and the cost of alcohol or other anti- freeze compound, it is scarcely more expensive to run a car during the winter than during the summer, while it may be most expensive to lay a car up and have it meet the fate of the one I described above. Also, a car that is in daily use must receive a certain amount of care to be kept running efficiently, while the car that is locked up in a cold, sometimes snowbound, garage scarcely invites attention. i? YOU intend to run your car through the winter, as most people do, you must do three simple things: Prepare the engine for anti-freeze compound, put in the anti-freeze compound, and renew the latter as it evaporates or is lost through leakage. The first of these precautions amounts to little more than seeing that your water circulation system is tight. A small drip during the summer is inconsequential; it means merely adding water from time to time. The same small drip in the winter, though, is likely to run into money, since it is carrying away an anti-freezing mixture that costs you between 50 cents and a § GASOLINE TANK TURNED OFF Tighten and E— . GREASE BRAKE CONNECTIONS, F—Cylinder inlet hose. RADIATOR DRAINED AND STEERING CONNECTIONS - PROTECTED WITH A QUART AND JOINTS i H—Filange gasket. OF ALCOHOL Renew if necessary. Tighten WINDOWS, VENTILATOR Wash clean CAR LOCK APPLIED AND WINDSHIELD CLOSED cars supplied perfect illustra- tions of what noi to do with your automobile in winter, whether you run it, or keep it in your garage. To operate a ear through the winter without preparing it for the ravages of the weather is PLACECARON REMOVE THE STORAGE | APPLY BODY POLISH almost as foolish JACKS OR BLOCKS BATTERY OVER THE PAINT as it would be to try to make DEFLATE THETIRES APPLY THIN COATING yourself comfort- able for the winter in a house without a heater. And to keep your car in the garage for several months without safe- guarding it against its insidious enemies, OF VASELINE OVER THE NICKEL TRIMMINGS If you are storing your car for the winter, the precautions indicated above will save you umnecessary trouble and expense when you bring it out in the spring Qed Oe on er =» & a.™ wea a ke que rad The tail Perc HAL Pere Poun Ne point in t] tion, alco] evap

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rs B d as chout it is ay be vinter ghtly e and anti- arcely luring mmer, ive to et the above. > must -are to while a cold, garage yur car most simple ine for in the renew r is lost -autions 1 seeing system ‘ing the it means m time drip in y torun carrying ure that ss and a § INECTIONS, cTIONS ~ ATOR OSED ——_—__— \ AR ee TD POLISH MINT 1E .e winter, . will save expense ne spring January, 1925 dollar a gallon. Reference to the accom- panying diagram will show you where to look for leaks and how to repair them. Rubber hose connections are the most frequent cause of leaks, and it is usually well to renew these before filling with anti-freeze if they are old or their condi- tion is doubtful. Renewal of the pump packing is another job that should be done be‘ore the anti-freeze is placed in the radiator. It is also well to tighten the hose clamps and pump gland every two weeks or so during the winter, CYLINDER since these parts may APPLY SMALL QUANTITY OF OIL IN EACH ENGINE POPULAR SCIENCE MONTHLY which they are mixed, and that you must make up for this difference when you replenish the suodply. In other words, use a slightly stronger solution than you used when filling the radiator for the first time. Calcium chloride does not evaporate, so that if you use this solution, unless your car leaks considerably, it will be necessary for you to replenish the liquid in the cooling system with water only. become loosened in driving. Small Jeaks in the OF TENSION RELIEVE FAN BELT 87 age, and storage, unless accomplished in- telligently, means trouble. The first thing to do with a car that is to be laid up for the winteris-to drain out the old engine oil and refill with new. This prevents heavy particles settling and clogging the oil ducts. Next, drop a tablespoonful of cylinder oil in the head of each cylinder and crank the engine vigorously to spread the oil on pistons, rings, and cylinder walls to prevent. rust. Drain the radiator etre and pump, and pour a CONTROLS, SPARK-PLUG OF THE quart of denatured al- THREADS AND EXPOSED DISTRIBUTOR cohol into the radiator STEEL PARTS COATED WITH GREASE DRAIN PUMP radiator can be re- paired with a radiator leak-sealing compound. This should be done a couple of weeks before the anti-freeze is used, to give the cement a chance to set and harden. Sometimes the solvent action of the anti-freeze will cause unsuspected leaks to appear. A pound of washing soda dissolved and poured in the radi- ator will wash the dirt and slime from the cooling system and dis- close the location of such leaks in time to DRAIN CARBURETOR AND VACUUM TANK after closing the pet- cocks lest water be re- tained by clogged tubes or pipes. repair them. In addition to the various commercial anti-‘reezing solutions, denatured alcohol, a mixture of half dena- tured alcohol and half glycerine, and calcium chloride, mixed with the water in the cooling system in correct proportions, supply _ effective means of preventing a car from freez- ing. CONNECTIONS HE following tables show the propor- tions in which these mixtures should be used for various degrees of cold. The quantities given are for Ford cars, the radiator capacity of which is 214 gallons. The same proportions should be main- tained, of course, for larger cars: DENATURED ALCOHOL Percentage of Alcohol Quantity Freezing Point 10 1 quart 25° F, 20 2 quarts 15° F, 25 246 quarts 5° F, 30 3 quarts 5° F, below 40 4 quarts 20° F. below 50 5 quarts 35° F. below HALF GLYCERINE AND HALF DENATURED _ ALCOHOL Percentage of Mixture Quantity Freezing Point 10 1 quart 25° F, 20 2 quarts 15° F, 25 214 quarts 5° F, 30 3 quarts 5° F, below CALCIUM CHLORIDE Pounds of Calcium Chloride Freezing Point 5 18° F, 8 0° F, 10 15° F. below Neutralize by the addition of ammonia to the point where the litmus paper fails to turn its color. Your car will lose anti-freeze mixture in the winter through leakage, evapora- tion, or both. If you use alcohol, or alcohol compounds, remember that these evaporate faster than the water with SHELLAC RADIATOR-HOSE for the winter months. XOAT «all exposed metal parts of the engine with cup grease. Relieve the tension of the fan belt, and coat the radiator hose con- nections lightly with shellac to prevent de- cay of the rubber: The various movable parts of the chassis— brake rods, connections, steering-gear parts and the like—should be protected from rust with cup grease. It is not necessary to drain the gasoline tank, but DRAIN: CRANKCASE AND REFILL If your car is in good mechanical condi- tion, the foregoing is really all you need to do to enjoy it through the winter. How- ever, you may live in a region where heavy snows and poor roads make winter motoring impossible. That means stor- COAT STARTING MOTOR AND GENERATOR WITH CUP GREASE Parts of the engine and electrical units that require attention before storing your car The simple precautions to be taken in each case are indicated Winter Driving Hints 1. Be sure that the cooling sys- tem of your car is tight against leaks, and filled with the correct anti-freeze solu- tion. 2. See that the carburetor is ad- justed to a “rich” mixture. 3. Before starting in cold weather, always push out the clutch pedal. This will relieve the drag of the trans- mission on the starter. 4. The instant the engine starts, open the choke partway, and as soon as possible open it fully. 5. Let the engine warm up be- fore trying to drive fast. 6. See that you always have an adequate supply of the cor- rect grade of oil in the crankcase. the fuel line petcock should be closed, and the vacuum tank and earburetor should be drained to avoid leak- age and free:ing if water has collected. The screwed hubs and retaining nuts of disk wheels or demountable wheels should be covered with a film of heavy oil. The axles should be raised and the car set on jacks, paving bricks, wood blocks, or other substantial supports to bring the tires clear of the floor, and the tubes should be partly deflated to relieve the casings of strain. If the garage is damr, it is well to coat the juncture of tire and rim with shellac to avoid the possibility of the rim’s rusting. The electrical system demands especial care. Generator and starting motor should be protected from dampness with cup grease. The storage battery should be removed and should be charged once a month. This is important, for a dis- charged battery will freeze, and even a fully charged battery will discharge through internal leakage when not in use. The distributor head should be li‘ted and the breaker mechanism oiled to prevent rusting. The wiring, however, requires no special protection. If yours is a closed car, close it up tight during storage to protect the upholstery from dust, dampness and vermin. [If it is an open car, put up the top and button all curtains in place. This will prevent top and curtains from cracking, wrinkling, or rotting. All nickeled parts should be smeared lightly with vaseline to prevent tarnish, while a liberai coating of body polish ap- plied without rubbing down will protect the paint against sweating and moisture.

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88 POPULAR SCIENCE MONTHLY Kinks for the Home Garage How to Save Your Time ARAGES are normally narrow and any special equipment placed along the sides cuts down still more the limited space. After fouling his bench with the front wheel hub and tearing down an electric conduit with the opposite wheel, one car-owner made a wheel trough or runway at one side by bolting down “two by fours” as indicated in Fig. 1.

OHNSON, one of my neighbors, who had done an extra good job of washing up his car in the garage one afternoon recently, drove into the garage as usual that evening and, in spite of his brakes, smashed both headlights on the garage workbench. The combination of water and oil was too much for the brakes. Reasoning that rubber would be the best thing to clear the smooth concrete of water, Johnson made a simple squeegee from an old inner tube, strips of iron, a pipe nipple, two nuts and a broom handle, as shown in Fig. 2. An oil pan was made by bending a sheet of roofing BROOM nen

Fig.1. Runway guides car into narrow garage

January, 1925

in Looking After a Car MANY tops of closed cars are snagged by overhanging branches of trees and _ holes 2 or 3 in. long are torn. The repairman would prefer to replace the entire top section, at con- siderable cost, but the owner himself can make an inexpensive and quick repair through the use of a cementless or ‘‘cold”’ patch (Fig. 4). Clean the rubberized fabric with gaso- line around the broken area and apply a patch long enough to overlap the ends of the tear. This should be applied as ona tube, and the patch is dipped in gasoline before placing over the break. It is advis- able, however, to place a weight, such asa flat-iron, over the patch for several hours; VERY car-owner has individual meth- ods of simplifying and expediting repairs. A striking example of this is the case of a motorist who uses ordinary spring paper fasteners in many ways, three of which are illustrated in Fig. 5. Used as a bolt holder,the fastener makes possible the insertion of bolts single handed in

tin into a tray as indicated, the corners being made without rivets or

SAWDUST on the flanges of engine bases, where the worker

difficult places, as &

cutting. PAN BENT UP y Now,afterwash- aT EDGES “~_S J reach the bolt head ing up, Johnson , : Li Ooi % and nut at the # 4 i as - ligh ; quickly sweeps the Fig. 2. Garage floor squeegee and oil pan Fig. 3. Quick-acting jack for light cars same: time. In water off the floor. eREVENTS BOLT HEAD — placing gaskets The pan is filled FROM TURNING —~ (9 under crankcase with sawdust and

SAD-IRON ON PATCH

placed under the —S>= engine to catch the ; dripping oil. When draining the crankease, trans- mission, or differ- ential, the pan is used as a catch basin. These simple expedients result in the floor’s remaining clean all the time. John- son also saves himself the task of wiping up the grease.—G. A. L.

CEMENTLESS PATCH Fig. 4. Patching a top , HE light, quick-acting jack illustrat- ed in Fig. 3 is a great convenience in the home garage. The base, A, is 2 by 4 by 12 in. B, which is screwed or nailed securely to it, is the same thickness as the lever, D. There are two pieces, C, fully 1 in. thick, screwed to either side of B and slotted as indicated. The slots permit a quick, easy adjustment to either the front or the rear axle of a Ford or similar light ear. D should be of ash or other hard, tough wood. An ordinary bolt will do for the pivot, but a %-in. gas-pipe, cut just long enough to go through the uprights and lever and held in place by a light bolt and washers, is better because it affords a larger bearing surface and re- duces friction. The fastening loop, of No. 9 wire, has an eye at each end and is held by a bolt through B.—Howarp E. Goon, Water- ville, Ohio.

ries SS g FS LOWER COVER OF CRANKCASE Fig. 5. Paper fasteners simplify repair work => 46 |

A Wealth of Mechanical Articles in This Issue HETHER you are an amateur ora professional mechanic, a beginner or an expert, you will find many articles of absorbing interest in the following pages—things to build, household utilities, ways to keep your home shipshape, and better methods for the shop. The Home Workshop (pages 89 to 129) this month has 42 articles with 70 illustrations. The Shipshape Home Section (pages 122 and 123) contains three columns of useful household ideas. The Better Shop Methods De- partment(page 94 and pages 130 to 140) has many labor-saving hints for mechanics packed into its 15 articles.

cover plates, it is the gasket with the teners are placed on opposite sides of the cover to hold the cork or felt gasket in line, and it will stay in position while the work of inserting the bolts is going on. By attaching a spring fastener to the lamp cord of the trouble light close to the lamp, it is possible to snap the lamp quickly to any part of the chassis adja- cent to the work. HE electrical difficulties to which a car is subject often are due in part to short circuits and grounds that exist where the wires come in contact with parts of the engine frame or body. Many manufacturers advise that the car be re wired after a period of service to safe guard the electrical system, but the mul- tiplicity of wires makes the rewiring 4a time-consuming job. To eliminate most of this work, one owner of a completely equipped car sim- ply reverses the wires wherever the in- stallation permits. The wire is removed; turned end for end, and reconnected. Any part that is abraded, unduly flexed or weak, is protected by the shifting. Another economical procedure is t0 reverse the wires from the coils to the timer on light popular cars. cannot easily § difficult to aline § bolt holes. Fas- §

> oe oe CoOectojo = ef ™ & mH em Th jh] > ew

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1925 : ‘ ; sat d by holes would ; con- make 1e use gaso- oply a nds of sona 1soline advis- ch asa hours, -meth- editing 3; is the -dinary ways, ig. 5. a bolt astener ible the f bolts ded in Aces, as nges of pases, worker 2asily olt head at the e. In gaskets -ankease es, it is (oO = aline with the Fas > placed ite sides over to cork or t in line, 1 stay in ‘ting the or to the yse to the the lamp ssis adja- which a in part to hat exist tact with y. Many car be re to safe the mul- wiring 4 work, one 1 car sim- pr the in- removed; ected. Any flexed of ng. ; ure is 1 ils to the January, 1925 POPULAR SCIENCE MONTHLY 89 Arthur Wakeling, Editor Construction Simplified for the Amateur Craftsmen OR the home worker F who wishes to build a piece of furniture that is a little finer than anything ordinarily undertaken by ama- teurs, the accompanying de- tails of a Sheraton table have been prepared. The table is one to grace any room. If carefully constructed and well finished in either mahogany or walnut, it will grow richer and more beautiful with age. It is exactly the type of furniture that becomes a prized heirloom. And the very fact that it is put together painstakingly by hand and is the product of the loving labor of many evenings at cellar or attic workbench adds to its intrinsic utility and value. The design is based upon a mahogany table in Sheraton style in the Metropolitan Mu- seum of Art. George F. Kaercher, the furniture-factory superintendent who prepared the working details, has made no attempt to follow slavishly the original. Using the museum piece simply to sug- gest the style, he has adapted the design to the requirements of home construction, simpli- fying it where possible. In size the table is one to commend itself for many pur- poses, especially when space is at a premium, as in a small room or apartment. The top is 2214 in. by 2 ft. 8 in.; with both leaves extended, it is 2 ft. 8 in. by 4 ft. \% in. The height is 2 ft. 5 in. There are two roomy drawers, one in each end. ° There is nothing particu- larly difficult about the con- struction. Any woodworker with reasonable experience in building simple furniture, such as most boys acquire now- adays in their manual-training classes, will have no trouble in understanding the drawings or performing the individual tool operations. Success de- pends, however, upon great accuracy in laying out the stock and fitting the joints. (Continued on page 124) 22%" i Ba @& FRONT Be L® vate ay fog BE gs WF ay | O- ° SHIDE VIEWS -es ASSEMBLY 36 SQUARE OR ROUND AND FLUTED baa VERTICAL + & SECTION THROUGH FRONT WITH ~ ~ DRAWER 777 PLACE STRETCHER SHELF a Ay? oo i ¢ TOP € Sf dL ee ee aie hr DETAIL of ‘ ONE QUARTER. SiH Of STRETCHER. [fii SHELF ~ ~~ Ui SCALE Photo Courlesy ~~» METROPOLITAN MUSEUM OF ART jer LARGE DETAILS ALTERNATIVE“ METHODS of DRAWER CONSTRUCION ~® SHERATON TABLE @ in MAHOGANY o- WALNUT. The DESIGN IS BASED UPON A MAHOGANY TABLE in SHERATON STYLE in the METROPOLITAN MUSEUM of ART. NEW YORK eo--t---->- ' End, side, and plan views of the table, and larger details of the corner construction, ‘drawers, legs, top, leaves, The parts are lettered to correspond with the bill of materials, which braces, and ornamental stretcher shelf. should be studied in connection with the drawings. Any dimensions may be found by using the graphic scales

Page 58

became thoroughly interested in something that was going on at our local station. The look in his eyes when Jim switched over to Kansas City, just to see it he could get them, told us a story we had never before realized. “What selfish idiots we have been,” said Jim to me later. ‘‘ Here we have been doing all sorts of tricks with our sets and never stopped to think that perhaps the rest of the family might like to listen in just for the enjoyment of the programs.” And then the idea came. We de- cided to build Dad a set for himself; a better set than we had ever built; a set good enough to look like a factory set and to work as no set ever worked before. So we built it, with all the skill we could muster. Before we started to make it, we asked Mrs. Smith, our next-door neighbor, to come in one day when Mother was out and tell us where she thought the set should be placed, and what sort of wood finish it should have to match our furni- ture, and similar questions that only a woman can answer. Then Jim, who used to work for a car- penter, built a real cabinet, to take a 7 by 21 in. panel. He made it of oak, carved with a pretty checkerboard de- sign. Then he stained and waxed it with much elbow grease, and put on fancy silver-plated hinges and catches. I was all for going down and buying the parts immediately, but Jim said, ‘“‘No, let’s figure out what color dials will look best, and what sort of panel, jacks, and D* dropped in on us one night and HOME WORKSHOP DEPARTMENT OF POPULAR SCIENCE MONTHLY Materials that Insure a Professional Finish ANEL—Standard, of guaranteed quality. Dials of same ma- terial and finished to match or to contrast artistically. Apparatus—Parts to match in ap- pearance. All exposed metal to be nickel, silver, or gold plated. Wiring—Silk-covered magnet wire, braided copper flexible leads, and tinned cr gold-plated copper bus bar for connections. Bends to be neat and all wires as short as possible. Use only genuine spaghetti. Insert key socket bushings where wires pass through cabinet. Cabinet—Genuine mahogany, wal- nut, or oak, with furniture finish. Avoid—Fiber, pasteboard, cheap rubber, paper, iron, wood (except for cabinet and baseboard), compositions known as ‘‘mud,” friction contacts (except where absolutely essential), cheap spaghetti, apparatus not of standard make and fully guaranteed. ( = / / A D (CC) \\ VS ) LJ YO PHONES? HORN? FIG.1 The average amateur would consider this a good layout, but it has several defects Fig. 1. soon. Let’s get the right trimmings if it takes a week.” I suggested that, as the radio stores are full of splendidly designed sets, all we had to do was to find one with a cabinet like ours, and see what trimmings it had. We found what we were looking for in a Mission oak cabinet. It had a grained panel engraved in white, with lustrous black dials and nickel-plated trimmings. We almost lost our heart to some other color combinations, for there was one set in a mahogany cabinet with a lustrous black polished panel and dials, highly polished jacks and clear white engraving _—_ —a jewel among sets—and another set in an ornamented green leatherette case with an imitation mahogany, panel en- graved in gold, dials to match, and gold- plated jacks and screws. Knowing what sort of dials and panel trimmings we had to buy, the rest was easy. Of course, we were particular to get the best instruments both in efficiency and appearance. We got coils wound with green silk covered wire, condensers designed for low loss, with verniers, and real spaghetti, soldering lugs, and tees. And then we planned the layout. We figured things out about this way: First, the set should come pretty close to filling the cabinet we put it in. And it should fill it all over, not in spots. Second, the front panel should be ‘‘balanced’’— a dial here, another there on a straight line with the first and the same distance from the edge of the panel; a little engraving to fill up a bare spot; and not too much “weight” on either side of the panel. Third, the instruments should be arranged with fair uniformity in the rear of the panel and in such positions that the wiring would be short and direct. Fourth, it should look as neat inside as out. We took our blank panel and laid out on it the dials, jacks, nuts, and so on, in January, 1925 Reeasins Up Your Radio Receiver Secrets of “Style” in Constructing a Good-Looking Set By W. R. Clendinning Designer of Radio Apparatus various positions. Our first trial was of a layout as shown in Fig. 1. Then we found: First, the grid wire would be 9 in. long from the secondary condenser to the grid of the radio-frequency tube. Second, the plate connection would be parallel to the grid wire. Third, the tube sockets and transformers were jammed together at the right end of panel and vet there was a lot of unused space at point marked A. To make a long story short, we juggled with front panel and rear panel layouts tor a couple of days before we drilled a hole in the panel. The last layout is shown in Fig. 2, and has the following ad- vantages: On the front panel, the 3-in. dial with the vernier, that is so neces- sary with the special feed-back coil used with our hook-up, and the two 4-in. dials on each side of it “balance” nicely. Placing the rheostats above the center line of the panel and the jacks in a straight line directly below them, gives more weight to the right side and eliminates the bare space usually found above rheostats in amateur sets. The layout of instruments behind the panel is more satisfactory, for the space is very evenly filled. The grid and plate leads are well separated, and the plate and coupler coil are entirely out of induc- tive relation, as they should ke. The aerial and ground binding posts are on a separate block at extreme left of panel, thus producing short leads to the 4-turn primary. The grid lead is 3 in. long from the feed-back coil secondary to the grid. The plate wiring, started at the plate of the radio-frequency tube, runs _4"DIALY 3"DIAL, _4°DIAL y gonee A | a =~ DD J) () ( O) DET. AMP i277 ae J} ® © r FF tomee PHONES = HORN \_\ ve SECONDARY / FEED-BACK COIL CONDENSER FIG.2 PHONE JACK HORN JACK Fig. 2. The revised design with apparatus and panel conforming to professional standards 4 in. to one side of the feed-back coil rotor, from the other side of the rotor to one side of the plate condenser (which is shunted with the plate coil) and from the other side of this shunt to the detector B- battery binding post, and to the grid con- denser of the second or detector tube. The layout finally being approved, we took our panel to a local engraver and told him to put his best man on the job. He also drilled it for us without burrs. Then came the wiring. This was play. Wherever a wire joined a binding post we used solder lugs and spring washers, (Continued on page 124)

Page 59

January, 1925 POPULAR SCIENCE MONTHLY 91 How to Finish Home-Made Furniture If you have a hobby for making cab- inets, furniture, porch swings, radio boxes, etc., you will find our book on Wood Finishing invaluable. Natur- ally, you want to give your handiwork a beautiful finish. Our Book gives complete instructions. It tells how to stain wood artistically—how to remove old paint and varnish—how to secure a beautiful enamel finish.

of a we

long rid of id be rmers nd of nused » we rear days the mm in r ad- . dial eces- back and of it stats and velow 5 side ually ts. d the ace is plate plate nduc-

posts eft of o the 3 in. | FREE-25¢ Bookon °. st |) Wood Finishing

’ This book gives complete instruc- od It tells how inexpensive soft woods AMP tions for finishing all wood—hard cREATM E Ny may be finished so they are as beau- as or soft—old or new. Explains just FOR FORK tiful and artistic as hard wood. what materials to use and how to ; URNITURE Includes color charts — gives cov- apply them. This book is the work of ries ering capacities, etc. Contains experts—illustrated in color. Con- 2 practical suggestions on making your tains a hundred wood finishing hints. xe ‘S.C JOHNSON E>! home artistic, cheery and inviting. The »Wo “NE, WIS.U.SA RN JACK lards :k coil (Penetrating) stor to Johnson’s Wood Dye is for the artistic coloring of all cheat aaaags ero aeseousee: 1 RACINE, Wis. hich is wood. It is very easy to apply—dries in four hoursand g “<The Weed Pianis name poe teres jon om the will not rub off or smudge—penetrates deeply, bringing § ——S (Canadian Factory—Brantford) r—l B- out the beauty of the grain. Made in 17 beautiful 3 za Please send me free your Instruction Book on Home f ~ ga shades, among the most popular of which are: i i Beautifying and Wood Finishing. I enclose 10c to fj ube. cover postage and wra ing. ed, we 123—Dark Oak 131— Walnut i = i range 129—Dark Mahogany 126—Light Oak 4 MY DUALSR wW........... 5... ncecsscceaee i he job. 127—Brown Mahogany 124—Golden Oak i ARTISTIC - rrs. Order Johnson’s Wood Dye Sinton your dialer by nein a Ww 0 OD PAP INMUC sc cc ccccceccuewnssceseusdaueaauname ' s play. and number. } Fy HES gZ post i NIS PGATONE 6.6.0. vcvcinconccccovcveseecsscssaemuenn g wie S.C. JOHNSON & SON, RACINE, WIS. ced nad Biate 2 8 col : “The Wood Finishing Authorities” Tieiangpusenanceundcessnenassrinsinnseniandiiiiiaae © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS, See page 31.

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92 POPULAR SCIENCE MONTHLY January, 1925 Making and Setting a Door Frame ) J HEN the home mechanic cuts a \V new doorway in a partition, he is confronted with the problem of setting a door frame in the opening; and if he is not merely shifting the location of a door, he has also to make the frame. If the opening is trimmed properly for l-in. jambs, it will be 214 in. wider than the door (allowing 1% in. for the finished thickness of the jambs and 1 in. for plumbing) and 2 in. higher, allowing 34 in. for the head jamb and 114 in. for leveling. A straight-edge 6 ft. 4 in. long is neces- sary. This may be made from an old casing or any suitable board, with both edges straight and parallel. With this test the plumbness of the trimming studs, and with shingle points block the hinge stud behind the hinge positions to plumb- ness. From a board the width of the jambs cut a piece equal in length to the width of the frame inside at the head. Use this piece to serve as a spfeader for QD) ))) 2 BEVEL JAMB EDGES 32" POINT: :, Fig. 3. Shingle points used as wedges, a dado, and properly beveled jamb edges the lower ends of the side jambs and to aid in squaring the opening. Stand the frame in the opening, and, holding the level on the edge of the hinge jamb, plumb it with the wall and tack the top and bottom with 8d. finishing nails. Level the head, and cut off the bottom end of the longer side jamb. If the side jambs are sprung edgewise, the straight-edge By Edwin M. Love Fig. 1 (at left): Plumbing the hinge jamb of a door frame with a straight-edge and a level Fig. 2 (below): Cutting off the end of the shin- gle points or wedges used to block the door jamb out from the stud behind and level must be used to insure the jamb’s being plumb. Drive shingle points between the stud and jamb in one or two additional places, as shown in Fig. 1, until the jamb is straight, and nail solidly to the stud- ding through the portion that will later be covered by the door-stop. Proceed in the same manner with the lock jamb, being careful to block where the lock keeper is to be fastened. If the wall is so much out of plumb that it is inadvisable to set the frame plumb edge- wise, be careful to keep one jamb as much out of plumb as the other, or the door will appear to be twisted when shut. Wedge the bottom of the jambs tightly against the ends of the spreader, nail solidly, and remove the spreader. Block the top jamb and cut off the projecting points of the shingles with a saw, as shown in Fig. 2. Breaking off these pro- jections with the hammer is doubtful economy of time, since the jamb is likely to be knocked out of true. To make a door jamb, cut the stock for the side jambs 3 in. longer than the door. Clean up the face side and straight- en one edge, beveling it toward the back, as illustrated by Fig. 3, so as to insure a tight joint between it and the casing. Gage the stock in width about 3/32 in. wider than the thickness of the partition, rip to width, and bevel the other edge as well. Leaving 1 in. of stock above the head © jamb, dado for the head jamb 3¢ in. deep and just wide enough for the end of the head to fit in snugly. A good method of making the side cuts is illustrated in Fig.4. Tack a short straight-edge across the jamb as a guide for the saw (cutting in the waste wood, of course) and hold another strip lightly against the saw. This insures a good, clean edge. Chip out the waste wood roughly with a chisel and finish with a light cut. Assemble the parts by nailing into the ends of the heads with four 6d. box or finishing nails, and gage a pencil line around both edges a trifle more than 14 in. from the face to guide in placing the edge of the casing. To set a new frame, determine the height of the head jamb by marking on '} E ‘ Fig. 4. Using two strips of wood to guide an ac- curate saw in cutting a dado in a door jamb the wall. Stand the jamb in the opening, and scribe the bottom ends to the floor, being careful to set the scribers for the exact amount to be cut off. This fits the ends neatly to the floor. ARCHED openings will be the subject of the next article in Mr. Love’s in- structive series. A Folding Screen for Your Open Fireplace By E. E. Scott FIRE screen is a neces- sary adjunct to every home fireplace. Be- cause of the high cost of real brass screens, however, many otherwise artistic chimney corners are made common- place by the presence of a The completed brass screen, which cost only $3.50 for ma- terials, is shown at the left cheap black spark arrester de- signed for utility but not for beauty. The cheapest solid brass fire- screens cost at least $2 a square foot and it takes a minimum of 8 sq. ft. for asmall fireplace, that is, one with an open- ing 26 by 30 in. Sufficient material to make a four-section screen of this size Details of can be bought for the small sum of $3.50. Each section of the screen illustrated is 1 by 2 ft. The frames are made of bar stock brass i by 1% in., cov- ered with 12-by-12 brass mesh, \ that is, mesh about as fine as | | fly screen. | OVAL TOP | To make the screen, obtain 24 ft. of bar brass from a hard: f ware store or mill supply house and saw it into eight 24-in. lengths and eight 11-in. lengths. The short pieces wasnitaiied | the screen and sugges- tions for or- namental tops shown at the right HOLE FOR RIVET SILVERSOLDERED BUTTJOINT Voth, are “‘butted”’ against the ends of the long strips to form a hollow rectangle and are brazed together. (Continued on page 118) | | |

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——_— oo January, 1925 POPULAR SCIENCE MONTHLY ln, A A OO OE LG eee eee ee eee eins FARAWAY GETS STATIONS FAR AND NEAR—LOUD AND CLEAR Radio Fans tell of FARAWAY’S Amazing Long-Distance You, too, can own a Faraway with our unique MONEY-SAVING plan 6 CANNOT imagine how you can manufacture these Faraway sets and sell them at your retail prices,’’ writes M. N. Jefferson of Salt Lake City, Utah. Mr. Adamson of Brampton, N. D., says: ‘‘We’re all ‘crazy’ about the Faraway sets and I sell them as fast as I order them.”’ Almost every mail brings some enthusiastic report from a Faraway user. They do not realize that their successful experiences with Faraway are being duplicated night after night by thousands of Faraway set owners all over the country. “The Faraway is the sweetest and clearest set I’ve ever listened to—no tube howls—no distortion—it’s easily tuned and brings in fine volume. I have 143 stations logged so far and get new ones continually,’ writes J. D Shoptaugh of Bellevue, Ky. Operates with Dry Cells or Storage Battery Faraway sets are easily tuned, extremely simple to operate and always dependable. They operate with either Dry Cells or Storage Batteries. The latest improved type of set construction used only on high priced sets is employed. ee SATISFACTION GUARANTEED OR MONEY REFUNDED We guarantee all the things our users claim—namely—clear, sweet tone—fine volume—unusual long distance reception—can be logged—no tube howls, distortion or radiation. For beauty and fine workmanship Faraway sets set a new standard in radio receivers selling under $100—and you'll agree with us when you see it. For Faraway Cabinets are ornamental and massive—beautifully done in mahogany. The panel is finished in dull platinum with all calibrations finely etched in black, So why pay more? You'll wonder like Mr. Johnson how we sell Faraways at these low prices. Our unique selling plan is the answer. Don’t buy your radio set until you see the Faraway. We have a big surprise for everyone who writes for our literature and money-saving proposition. Mail the coupon today. Dealers—Agents Our Faraway proposition offers tremendous possibilities for you. Write quickly for plan and territory. ‘) THE FARAWAY RADIO COMPANY 653 W. Third Street Cincinnati, Ohio Performance Hundreds of Fans say they get from 10 to 37 stations in an evening, from New York to Los Angeles. What they say: **Crazy’’ about Faraway My customers are just crazy about Faraway sets and I sell them as fast as I order them. We readily pick up Boston, Dallas, Frisco, Pittsburgh and many other stations. R. J. ADAMSON, Brampton, N. D. One Sells Another I cannot imagine how you can manufacture these Faraway sets and se!l them at your retail price. I have been interested in radio sets for several years and I recently had the privilege of ‘‘listening in’’ on one of your 4 tube sets and was surprised at the wonderful results. Send me your literature at once as I want to buy one. M. N. JEFFERSON, Salt Lake City, Utah. Got 30 Stations Your 4 tube Faraway is fine. So far I’ve tuned in 30 known stations on the Loud Speaker. Send me a supply of order blanks and literature and expect many more orders. A. E. CRAFTS, Pittsfield, Mass. Frankly, I’m real enthusiastic about your Faraway two-tube set, and you may be interested to know that so far I have been able to get more stations than I can count. Here are some of them: KYW Chicago, WLW Cincinnati, WSAT Cincinnati, WOAT Wilmington, KSD St. Louis, WBAH Minne- apolis, WJAZ Chicago, WOQ Kansas City, WMC Memphis, WHAM _ Rochester, WOO _ Philadelphia, WOS Jefferson City, KGO Oakland, Calif. The range is all that could be expected and every- thing is loud and clear. I am sure I will be able to sell a lot of them in the future. Very truly yours, E. R. CARTER, Forest Hills, L. I. I have been using your 4-tube Faraway Radio set for some time now and I couldn't hope for better results. I have received as many as 21 stations in one eve- ning, including New York, Pittsburgh, Schenectady, Chicago, Havana, Omaha, Los Angeles, Dallas. Although I have gotten between 125 and 150 sta- tions, I continue to get new ones each night. I am 100 per cent Faraway now and I am making a lot of money, as you can see from my orders, selling others. I would be glad to recommend the Faraway Radio to any one at any time. Very truly yours, FRANK A. COLLINS, De Page Courty, Wir field, Ill. 2 tube Bswsm op apd Reweveies $29.50 MODEL F 4 tube set shown in ittustration$ O).50 for use with loud speaker...... IMAIL THIS COUPON! THE FARAWAY RADIO CO. 653 W. 3rd St., Cincinnati, Ohio Gentlemen: Without obligation send me: t ] Your literature and details of money-saving proposition, { ] Agents’ Proposition, [ ] Dealers’ Proposition. 2 ee rey Gity anid States 6... Sci oss crane en os eee © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31. Ss ll | er mney eye en ee 0 eR NE CT LL ALE LE I AA cet Se anne acer nee te a aR wo ie ero ine inne nt Ae err ee eA NT NGsiges ae ~ 4a

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POPULAR SCIENCE MONTHLY Better Shop Methods ai How Expert Mechanics Save Time and Labor How to Handle Rush Repair Work Old Bill Uses Shortcut Methods in By James Ellis Machine-Shop Superintendent P pv seven-o’clock whistle had blown some minutes before. Old Bill came into the shop through the side door, smiling to several of the men as he passed. It was pleasant to see his lathes and planers and drills cutting iron even before the night’s chill was off. He came to a lathe where a large piston was being turned. ‘Looks as though you will have the piston ready by the time Conley gets the crosshead,’”’ he remarked. “T guess I will,’’ the machinist “especially as Conley isn’t replied; here this morning!”’ “What! Bill exclaimed. head. chances. will do,” Old Bill already had been planed. In about two minutes, he was looking for Old Bill. “This job’s_ killed!” he said. “Killed!” Old Bill gasped. ‘“‘Why, that’s for the light plant at Hughes, and we hve to get it out. Let me see what is wrong.” “*Conley has planed it so that we can’t clean up the hole for the piston, for one thing,’ Laten explained, as he showed Old Bill the measure- ments. “And if we could, it is off center another way.” T’S no use to try to save that, boys,” Old Bill said slowly to the group that had gathered. ‘‘This one is good for scrap, and the “ sooner we get the foun- dry making another, the Conley not here?” Old “Where is he? We must have that crosshead!” He pushed his old cap back on his head and looked about the shop to see whom he could best trust to finish the cross- It was an important job, and he could take no “IT guess Bob Laten mused; “he’s young, but he is a careful fellow.” So it was not long before Laten was looking over the job that he was to tackle. He saw the broken crosshead he was to duplicate, and the new one in the lathe. It “Lots of us spoil work,’ said Old Bill, “but we don’t spoil the same thing twice” \! ‘2 better off we are. Bob, tell the foundry I say to make another one today, while I go and get bawled out over the phone.” He had promised certain de- livery on this job, and now he had failed. He would get another casting made, and in the morning he himself would see that no mistakes were made— at least, not in laying out the work. The crosshead is illustrated above. The © bE EDGE DS. —. © a } a BRACE oy LOCATE CENTER OF HUB E The new crosshead Machining January, 1925 old one had cracked and finally broken. In the resulting wreck of the engine, the piston and cylinder head broke. This had put the engine out of commission and a neigh- boring town out of lights. The following day Old Bill was on the job before the whistle blew. He went directly to the foundry to watch the new casting taken out of the sand. Two of his own men were there helping to clean it up. They soon had it in the machine shop and up on the table of a planer, still warm. Old Bill came over with a sketch he had prepared. “Tf Conley had made a little draw- ing of the job, the engine might be running now,”’ Old Bill commented. “It is a mighty good idea to make some sort of a drawing of anything with as many surfaces as this, so that you cansee all the dimensions before you while laying out the job. “We will get the center of the boss end (Fig. 1), so that we will know that we have stock enough to clean up the hole. This is one place where Conley didn’t leave enough. Then we will find the center lines on the other end (Fig. 2). Have to measure from the inside here, though, so that when we are through, both jaws will be the same thickness. “Having done this, we will plane off one of the faces. AND PUT CENTER PUNCH MARKS @ LOCATE CENTER LINES E ON OPEN END THIS DIMENSION LIKE OLD ONE ‘FIRST SETTING The steps followed in laying out and machining the crosshead. SECOND SETTING Speed in handling work of this kind depends upon an accurate layout and a systematic plan of operations Now, Bob, set up the casting so that the center lines we have just drawn are parallel to the planer table. Then draw a center line all the way around the casting with the surface gage.” Old Bill left to attend to other duties. “IT see where Cozxley made his mistake,’’ Bob said to his helper. “He did not find the center line, but set the casting up for the first cut on two parallel strips here (A, Fig. 3). That threw everything out.” By the time Old Bill got back, Laten had planed both sides of the casting to the finished (Continued on page 138) ON’T fail to turn to pages 130-140, where you will find the continuation of the Better Shop Methods Department. ~

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January, 1925 POPULAR SCIENCE MONTHLY 95 re The Best Tools ‘60 Good © n e h jor The PS yn ’ . ip Beginner © *h V- be d. ke ng so ns yb. nd we le. bg n’t the 2). re, th, off the ter e wn : Apprentice Set No. 901 a md When you learned to ride a bike Starrett Tools—the same fine tools you begged or borrowed from one _ they use themselves. In the No. 901 P| eal of the kids an old wheel to practice Apprentice Set you get the start of i on. That is, you did if you were a kit of well-made, accurate tools i Jey wise. that you'll use the rest of your life. if 30b But you can’t learn a trade that The Set is contained in a handsome F per. way. You must have accurate tools nicely finished wood case and is ; the to do accurate work and any me- sold by good hardware stores , 0 chanic will tell you so. That’s why everywhere. Ata price whichisnot /# i a crack machinists advise the young- the least attractive feature of this / if nied ster to start with his own kit of splendid kit. ; i 9 1 Bill Write for Starrett Catalog No. 23‘‘W’’ describing the uses of 2200 (l ~h Fine Precision Tools. Free. iy = THE L. S. STARRETT CO. q ) © World’s Greatest Toolmakers i; Manufacturers of Hacksaws Unexcelled 7426 a ie ATHOL, MASS. a 140, Set No. 901 consists of: No. 11, 6-inch Combination Square complete with Sliding Head and Center Head; No. 117 B, Center Punch i the No. 320, 6-inch Flexible Steel Rule in Pocket Case; No. 390, Center Gage; No. 79, 6-inch Outside Caliper with Solid Nut, No 73, 6-snch were Inside Caliper with Solid Nut: No. 77, 5-inch Divider with Spring Nut, and the Starrett Book for Machinists’ Apprentices, Vol. 1 10ds i © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS, See page 31. if ‘a i iG i= oN

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and the “—_ is cut clean and sharp No fumbling, no guess- work — no flaking or breaking of glass with the “Red Devil” Glass Cutter. Sim- & ply draw the tool ad Vv P : . lightly across the steel wheel pane of glass, and glass cutter makes the diamond expensive and old-fashioned. “Red Devil’’ ‘Glass Cutters It’s All In the Wheel! —each one sepa- rately hand honed and tested — the only one of its kind made. Ask any glazier what he thinks of it. continuous superior to that of a diamond cutter. No. 024— shown here, the glaziers’ stand- ard 20c each. Fix It Yourself with a ‘‘Red Devil’’ Plier You can make and mend hundreds of things with it. “Red Devil” Slip Joint Plier No. 850, with side cutter, is handy for keeping things in order. Drop forged from steel. No. 850— 5 in. $1.35 a pair. Look for the ‘‘Red Devil’’ trade mark on every tool. Then you'll be getting the same tools the skilled mechanic uses. On sale at all hardware dealers. Write for free mechanic’s © tool booklet. SMITH & HEMENWAY, CO., INC. Mfrs. of “Red Devil” Tools 264 Broadway, New York, N. Y. “‘Red Devil’’ Rapid Boring Auger. Bits are 33'3% easier boring, have 10% greater clearance, and bore with or against the grain of any wood. Style 2400—10/16 in shown here. 80c. POPULAR SCIENCE MONTHLY January, 1925 you have a clean, | cut | | ing the west. | They should be By Ernest Bade, Ph.D. N ONE of those long winter evenings when you turn to your workbench for a few hours of amusement, why not build a bird house? It is not too soon to get ready for the return of the songsters, for January and February are the proper months, contrary to general belief, for hanging up bird houses. There is more to making successful nesting homes than one is apt to think. Boxes roughly knocked together and attached in any location that happens to be handy are useless. Even a good bird house will have no feathered guests if it is | hung on a long, thin, shivering pole or in | an otherwise unsuitable location. The birds seem to prefer houses built entirely of wood. The cavity dwellers fancy a house like a wood- pecker’s hole, with a narrow opening at the top and a large oval cavity at the bottom. The entrance hole, however, should be adapted to the size of the bird that is to use it. Bird houses should be hung perpendicularly with the en- trance hole fac- An ideal home for wrens (above) and a starling or wood- pecker house, which must be quite large (at right) fastened rigidly so as not to rock violently in the wind. Chickadees prefer to build in fruit . An open robin shel- ter placed against the wall of a house (above), and a well designed bird house for either wrens or chickadees (at right) Natural house for chickadees (at left); a poor box on too thin a tree, and a comfortable swal- low house’ under the eaves (below) trees where plenty of underbrush is found. The house should be attached about 12 ft. above the ground and partially concealed in the foliage. Underbrush is necessary, since these birds do not like to fly over long stretches of open ground. Birds that dwell in deep cavities, such as bluebirds, require houses that are partially open. Swallows and other re- lated species prefer long, horizontal nesting places. These may be attached beneath gables or eaves of houses, well protected from the rain. Birds may not appreciate architectural efforts, but it is just as well to make their houses neat and attractive. Common sparrows are the enemies of songbirds and should be discouraged. Wrench Prevents Staples from Bending under Hammer Blows N DRIVING the staple for a barn- door hasp, especially if the wood is hard, the sides are almost certain to spread apart, causing annoyance and extra work. This can be prevented by placing a wrench over the sides of the staple before it is driven. Oak fence posts cause the same trouble in driving fence staples, but a thin wrench, car- ried along with the staples and ham- mer, will help. How to drive a hasp staple easily © This seal on a radio cr tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31.

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January, 1925 POPULAR SCIENCE MONTHLY No. 772 45-volt large vertical Price $3.75 pe 8 ces «ge patter one y 8 = p a ert cals 97° asd io jve 108 operating cost 22'4-volt Tuirty years’ experience in the manufac- large ture of dry batteries has enabled us within a the past two years to steadily and greatly : improve dry “B” Battery quality. Ever- Price eady “B” Batteries are now from two to $2.00 three times better than ever before. Eveready “B” Batteries are unsurpassed for endurance, economy and reliability as a source of plate current. These are strong statements, but they have been proved by tests in our own and in independent labora- tories. Check them for yourself on your own radio set. Get Eveready “B” Bat- teries. There is an Eveready Radio Battery for every radio use. Manufactured and guaranteed by . NATIONAL CARBON COMPANY, Ine. Headquarters for Radio Battery Information New York San Francisco Canadian National Carbon Co., Limited, Toronto, Ontario EVEREADY Radio Batteries © —they last longer areolar aw sani ons sli @ This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31. i ae Pea

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| 98 POPULAR SCIENCE MONTHLY

— would Radio d speaker Antenna Window lead in os — Connection wires Mechanic’slabor Hammer Clips Storage battery Nails | Lightning arrester ‘“B’” batteries Screws , Insulators Tubes Staples Y. .

| a pipes a = a = = | , q i \ 7 es - Til , = < Zr | iM ae NUM es What “complete self- contained” ee s the best of fun , we admit, to hook up a_ be as little fuss and bother to you as is humanly adio set, to string ame antenna from tree to possible. This means De Forest D-12 Radiophone ho ouse, to connect your gro soe: wire—at least it —the leader in the field—bearing the imprint of is fun i Meo ss u are mechanically minded. Dr. Lee De Forest, the man whose great invention If, however you want ete to use a radio Paved the way to radio broadcasting. set there are two things of primary importance— As to tone — it is impossible to des cribe the frst, that its tone quality sll be absolutely pure, clean and natural tone quality which this nstru- — and accurate; secondly, ae it shall ment gives. You simply must hear it toot ont DE FOREST RADIOPHONE

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January, 1925 POPULAR SCIENCE MONTHLY, 9 you choose ? DE FOREST D-12 RADIOPHONE Complete in one unit, with everything necessary to use it immediately — all at the one initial cost. Prices according to cabinet finish and batteries. B With dry eae In Fabrikoid cabinet . . - « « $161.20 on se In Mahogany cabinet . . . . 2. « « 176.20 With storage batteries In Fabrikoid cabinet . . 2. . .« «. « $180.00 In Mahogany cabinet . . . . . . . 195.00 means as in De Forest for yourself. And as for convenience, remem- ber these important things: it is self-contained and complete in one unit—usable within five minutes after it enters your home—easily movable from room to room because it does not need to be attached to either antenna or ground. . When you find the De Forest agent in your DE FOREST RADIO COMPANY, JERSEY CITY, N. J. vicinity you find a man who knows radio—a man who has given us his word that he will see that every instrument he sells is thoroughly inspected and properly serviced after the sale. Avail yourself of his help. He desires, as we do, that you should get the fullest enjoyment and satisfaction from your instrument. Also makers of De Forest Tubes, The “‘ Magic Lamp ” of e ~ DE FOREST RADIOPHONE REG. U.S. PAT. OFF. REG. U.S. PAT. OFF. ® This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31.

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Notice how the automatic op- eration of the “Yankee” Rat- chet Bench Drill leaves one hand free to hold the work— a pgreat con- venience. Away goes drilling trouble HE “Yankee” Automatic Friction and Ratchet Feed takes the place of hand feeding. Saves drills. Just turn crank and Friction Feed runs drill down to work; then Ratchet Feed automatically operates and feeds at the proper rate, with the right pressure. Automatic throw-off prevents jamming. ‘“*VYANKEE”’ Ratchet Bench Drill No. 1005. Illustrated. Two Speeds, 3-jaw chuck. Holds up to % in. No. 1003. One Speed, 3-jaw chuck. Holds up to %4 in. “YANKEE” Vise No. 990 For use on bench drills and other machines. True on all sides. Swivel jaw. Jaws 23 in. wide, 134 in. deep. Dealers everywhere sell ‘‘Yankee’’ Tools Write for FREE ‘“‘YANKEE’’ Tool Book “YANKEE” TOOLS Make Betliv Mechanica NortH Bros. Mrc.Co., Philadelphia,U.S.A. | POPULAR SCIENCE MONTHLY January, 1925 By Lawrence B. Robbins HE furnace-man shook his head after inspecting my old hot-air heater. ‘This furnace isn’t even worth taking in trade,” he said. ‘‘Firebox is cracked, casing pretty well rotted out, an’—fact is, she.ain’t much use. Tell you what I’ll do —Il’ll ’low you $10 fer old junk an’—” “Nothing doing,” I expostulated, for I had suddenly become possessed with an idea. To begin with, this particular heater did have a cracked firebox, and so on; but I knew there were ways of mending such things. Then again, the single-pipe or ‘“‘pipeless’” furnace had just come into vogue in our neighborhood. I wondered if I could change this old-style coal-eater into an economical single-pipe furnace. That afternoon I took down the register and the smoke pipes and cut off the cas- ing bolts with a cold chisel, as the bolts had been burned tight after 15 years of exposure to heat. As fast as the scale and soot were re- moved from one see- tion, I inspected it for cracks, which I closed solidly with iron cement. Then I chose the spot in the house for the one big register and proceeded to reassemble the fur- nace directly below it. The ashbed sec- tion was cemented to the floor to pre- vent air from enter- ing underneath and the sections were made gastight at the joints with stove putty. The casing was replaced with new bolts and a gsmali length of wire wound around each one, the use of which will be explained further along. The bonnet, or top conical casing, then was altered. The heater pipe stubs were removed and each opening was closed with a plate of sheet iron with a little tab at each side to hold it in place. The joints were made absolutely ticht with stove putty. The bonnet be- Next, the en- fore remodeling tire circular top of the bonnet was removed, a 38-in. stub clinched in the opening, and the bonnet put in place over the furnace. The method of returning the cooled air to the heater puzzled me at first, but Salvaging a Worn-Out House F urnace atrmnste ae a . 18 DIA. STACK : GALVIRON BOX ini GZ yf i pO" X30: X20" " = ; aS ie 4 WA S cemene 4 f ] | | i WH : ~ NUL p spestos OVER WIRE 12" COLD-AIR PIPES The construction used for connecting the old furnace to a standard single-pipe floor register finally I hit upon the solution. I had the galvanized iron box shown above made at the tin- smith’s. This was nailed inside a 30-in. square opening cut in the floor and placed so that the two 12-in. stubs came at opposite sides of the furnace door. -These stubs ‘were connected with fitted in the bottom of the casing by 12- ‘ in. pipe and elbows, shown in the large photograph. A stack slightly more than 18 in. in diameter and 24 in. high was fitted to The rebuilt furnace, which uses one-third less coal than before it was reconstructed the stub over the top of the bonnet and to the circular ring on the floor register. The register was laid in place and the assembly was complete. The casing was covered with 1-in. mesh poultry wire, pulled tight and secured by the little wires previously mentioned. The netting was covered with an inch of asbestos meal mixed with water to form a thick paste. This was allowed to dry a week and then, after the smoke pipe and dampers had been connected with the furnace, a gentle fire was built and kept going all day. The result was a pure white coating for the entire furnace ex- cept the door facing. A new one-pipe furnace would have cost about $150. I rebuilt the old one in spare time at a total cost of less than $45, including the new register facing, which was $12. Since this change I have heated my house on one-third less fuel and have gained 50 per cent in heat. two similar stubs | © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31. ~s A

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wena w @ WV WV ~~ S = *.. > Oo ~~ ve 15, ich ny ive

January, 1925 POPULAR SCIENCE MONTHLY 101

SLi a ‘2 adiotikes 4

~~ esses and Pictures BY Fleren Cooswerl

vox g THE MAGNA coal ee = A book the whole family will enjoy— sent free on request LLUSTRATED above is the Magnavox E new Magnavox Receiver has assumed a Radio Receiver TRF-5, a 5-tube place of acknowledged leadership among the — “4 tadio frequency circuit encased in handsomely carved mahogany cab- ==4) enduring radio achievements of the year. inet. This set, without tubes or bat- teries, represents remarkable value.

IS, aay ? haea Send me a complimentary copy of ee aaa Aaa a : Radiotikes, the “funny people” of radio. ew York: icago: an Francisco: 350 West 31st St. 162 N. State St. 274 Brannan St. Canadian Distributors Perkins Electric Limited, Toronto, Montreal, Winnipeg

FS) This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31.

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102): POPULAR SCIENCE MONTHLY .- January, 1925 value. many a “cuss word.” particular about their tools. and a joy to use this wrench. Roxbury, Ty Hifi|} In Steel Handle —Eight sizes from 6” to 48” In'Wood Handle =. 8,10, 14 inch TRIMO Turns Anything That’s Tight Monkey Wrench, Chain Wrench or Pipe Cutter ask to see a TRIMO and judge for yourself as to quality and Endorsed by The Popular Science Institute of Standards Keep a Trimo handy. It will tighten up or loosen anything that’s round or square or in between‘ dnd it saves you many a penny, many a minute and The Trimo is built for men who are Superior design and finest materials and work- manship make it a satisfaction to own And it’s really more economical in spite of the few cents saved by buying a cheaper wrench, because insert jaw in handle and all other parts are readily replaceable at small cost so that you can keep it as good as new indefinitely. Your dealer will gladly sell you one. Just be sure and say “a Trimo.’’ Trimont Mfg. Co. Mass. TRIMO Aliging the Wheels of Your Auto | | WAS coming into the city the other day when I noticed the car ahead of me acting in so queer a fashion that I had my suspicions of the sobriety of the driver. The car would appear to be going straight ahead when it would swerve 8 or 10 feet to the side of the road. The driving was so erratic that it was dangerous to at- By Ray F. Kuns Principal, Automotive Trades School, Cincinnati, Ohio - by excessive toe-in or wheels out of alinement. Wheels out of alinement may be too close or too far apart when measured across the front; either is dangerous. What happens to tires when wheels are not properly alined is shown in the picture of the worn tire. The wheels in this case were thrown slightly out of line by strik- tempt to pass. Fi- nally, selecting a place where the road was wide, I did pass and thenstoppedand flagged the driver. He seemed willing enough to stop. He had been in a slight accident and -was still excited. I explained to him ing the curb. While not noticeable in the steering, the damage showed up on the tire tread within a few days. The expert tire man will tell by the feel of your tire treads whether or not the wheels are out of line. Even if that his wheels were out of alinement and that to continue meant a certain wreck. We looked about and found a tough pole. This was placed over the front axle and used as a pry to straighten out the steering-reach rod. As this was pulled back into place, the wheels assumed a position more nearly their natural one. He was then able to proceed on his way with a degree of safety. In this case the wheels were out of line at least 6 in. It is about as safe to drive a car in that condition as to look down the barrel of a loaded gun. A car in this condition will jump beyond the control of the driver instantaneously. Even if a set of wheels is out of line less than an inch, there is undue tire wear and some danger of accident. The illustrations show what is meant drive; Bad alinement indi- cated by tire wear A car with excessive toe-in is dangerous to any misalinement causes tire wear the wear is slight, the sharp edges on one side of the tread pattern will reveal it. In alining front wheels, the first step is to loosen the tie-rod bolt through the yoke at the end of the steering-reach rod and remove it. Since the yokes are clamped on the threaded portion of the reach rod, it will be necessary to loosen the clamp bolt and then turn the yoke on or off, depend- ing on the amount and way in which the wheels are mis- alined. The center of the tires must measure from \% to % in. closer at the front than the rear. Set the wheel on a jack and mark the cen- ter of the tire by - holding a soft lead pencil against the tire as it spins. Measure with a stick. When the proper alinement has been ubtained, the tie-rod bolt is cleaned and replaced, the cotter-key inserted, and the clamp bolt locked tight. TIE-ROD BOLT ; TIE-ROD YOKE Adjusting the yoke Phonograph Record Replaces Noisy Alarm ()** merning, as I was awakened by the rasping call of the alarm clock, I decided to try a new way, so I rigged the old alarm clock to the phonograph and now I awaken to music. The bell is re- moved from the clock. One end of a piece of thread is tied to the alarm winding key; the other end is tied to the starting lever be very light so that it will break when the starting lever is pulled back. A stout string should be attached to the top of the clock to hold it steady. As the alarm winding key in the back of the clock turns to the left, it winds up the thread and pulls back the starting lever. Then the thread breaks, leaving the phono- of the phonograph. The thread should The alarm-winding key winds up a thread attached to the phonograph starting lever ss. graph running.— D. SNAVELY. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31. |i

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1925 January, 1925 POPULAR SCIENCE MONTHLY 103 Radiola Regenoflex Remarkable for its tone quality! Selective and non-radiating. With compartments to hold all batteries. With four Radiotrons : WD-11, and Radiola Loudspeaker . $191. Radiola III-A . ; : A $90, eae. Radiola Super-Heterodyne . . $269, (All these Radiolas complete except batteries and antenna.) e-in ; of eels \ nent rhen r is rhen own The htly trik- Vhile 1 the nage the in a tire y the tire r or s are ven if light, $s on tread ; step h the h rod s are of the || Christmas 7s Christmas =-ROD =||—with a Radiola Dd A Radiola stretches away through the narrow walls of the city apartment. It makes a new world of the old farm kitchen. It reaches out and out, KE and brings home the fun! yoke oe There'll be Christmas carols on Christmas morning. This sombot x Pe of qua’ oa There'll be music and laughter and lectures and - pit OMe 4 vel ~~ sports—day after day—week after week. The new e e e e e e - generation will grow up with a bigger world to live eae e Th ] d e ill e £ WantaRadiolaThis Christmas? in. e older generation will get new joy out 0 A gentle hint does wonders. Send m life. Everybody wants a Radiola! us the name of the relative who anit doesn’t know what to get you, when the top to hold “ a e 4 and we'll mail to him—or her— ck. A “There's a Radiola . for every purse a book about all the Radiolas 1S) : from $35 to $425. It may help. Or send for the booklet yourself ie Christmas ideas. Radio Corporation of America alarm 233 Broadway 10 — ps ae 28 Geary Street y in the New York .. Chicago, Il. San Francisco, Cal. =| Radiola he left, REG. U.S. PAT. OFF. up the d_ pulls starting hen the reaks, » phono- nning.— NAVELY. —— @ This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS, See page 31.

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NEIGHBORS When Ephraim Crosby made a clearing far out on Valley Road and built his house, he had no neighbors. He lived an independent life, producing on the farm practically all that hes family ate and wore. Emergencies—sickness and fire and pro- tection of his homestead from prowlers—he met for himself. Later he had neighbors, one five and another eight miles away. Some- times he helped them with their planting and harvesting, and they helped him in turn. Produce was marketed in the town, twenty miles along the cart-road. Today Ephraim Crosby's grandchildren still live in the home- stead, farming its many acres. The next house is a good mile away. But the Crosbys of today are not isolated. They yep with a nation. They buy and sell in the far city as well as the county-seat. They have at their call the assistance ve services of men in Chicago or New York, as well as men on the next farm. Stretching from the Crosbys’ farm living-room are telephone wires that lead to every part of the nation. Though they live in the distant countryside, the Crosbys enjoy the benefits of national telephone service as wholly as does the city dweller. The plan and organization of the Bell System has extended the facilities of the telephone to all types of people. By producing a telephone service superior to any in the world at a cost within the reach of all to pay, the Bell System has made America a nation of neighbors. AND ASSOCIATED COMPANIES ‘BELL SYSTEM One Policy, One System, Universal Service POPULAR SCIENCE MONTHLY

January, 1925

AMERICAN TELEPHONE AND TELEGRAPH COMPANY |

SIGNS, BANNERS, CARDS

. © # $150 to $3 with the aid of Letter Patterns. Simply trace around a letter pattern

@HOUR BATTERY CHARGING Brings tradetoyourshop. Pays 00 monthly profits. a Only $35 cash brings complete equipment for 8 hour battery sae oy Your big profits eas- and in. Made in a large variety < of carry small monthly y bayments. No etytes and Aan pon nd ne uild a big prices. Send stamp for free samples. John money-maki eer chargi ging best- ©. Rahn, 02433 Green View Av.,Chicago ness. Write for Free. Bulle

Hobart Bros, Co., Box P1, Troy, Ohio

ou be so tind as to add the name of one friends you believer will soon want radio Liberty 11.0.flouse,Dept. A-184, 106LibertySt..N.Y.

Write for our big money saving RECOVER IT $3.85 YOURSELF ND UP Make your car look like aun Made newandsaveabig labor bill. We have been making top recoverings, side curtains and seat covers for li years, We have patterns for all makes, no model too old for us. Easy to apply, poesia cnagie given.

or adio goods 7 ‘Thank yout)

THE LIBERTY TOP & TIRE COMPANY, Dept. E-8, Cincinnati, Ohio

- Home Works aioe ‘Dead Man’’ Anchors Aerial Guy Wires Firmly Any broadcast listeners, confronted with the problem of keeping their aerials up, resort to guy wires or ropes. The amateur’s method of anchoring guy wires, however, is nearly always most unreliable. Stakes driven into the ground should not be considered, as the swaying of the aerial mast eventually loosens if it does not pull them out altogether. The strong and dependable “‘ dead man” or anchor illustrated consists of six pieces of pipe, iron bar, or wood. It will be

Iron bars, pipe or strong wooden stakes may be used in construc’ing this “dead man” found impossible to pull out this anchor even if it is placed in very stony or loose earth. The guy wire or rope is fastened first to the top horizontal bar, passed under the bottom horizontal piece, and then carried to the antenna mast. In a test using a horse to pull against the anchor, spectators were dumfounded to see the horizontal bars gradually bent into a horseshoe shape while the stakes remained in the ground. This anchor also will be of interest and value, no doubt, to campers who have trouble keeping their tents on one spot.— JOHN H. SCHALEK, Pittsburgh, Pa.

How to Waterproof Shellac SHELLAC finish on furniture or woodwork can be made fairly water- proof by the application of two or three coats of banana “‘oil.”” The last coat of shellac must be sandpapered as smooth as possible. Apply the liquid generously with a soft brush such as is used for var- nish, and sandpaper each coat lightly. It dries with a dull finish, but this can be brightened by the application of furniture wax. Many amateur woodworkers are partial to a shellac finish, but refrain from using it because shellac, unless specially treated, turns white from moisture.

ris] This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 3}.

Kg RAE OD, eo EEO SELLE ZZ, a“iagiyys 7g, SLI Z LESS % Y \\ SS \\ N at * \ \ t N \ i ‘ \

Page 73

Sai a oe January, 1925 POPULAR SCIENCE MONTHLY Oh Boy—what fun! Big fights, sports, real mu- sic, talks crammed full of interest. All yours by radio—with a Matched Tone Headset! The Matched Tone makes both ears hear the same sound at the same instant. It gives you every syllable— clear, lifelike,’ vividly real. Get the world’s fun—and get it all— with a Brandes. ||P Drandes. shree at of th as . Navy nA usly ow Matched hed Tone var- Superior "e) | | care. | The name te n be Headset Talker iture : 7 in Canada Ee =| | “—~y} 32.1 to know in ‘Radio ated, C. Brandes Inc., 4925 RRA A OEE AOI a ee © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS . See page 31.

Page 74

106 POPULAR SCIENCE MONTHLY

— X CIR- KIT brings these Greater Circuits In a motor car—the engine. In a skyscraper —the substructure. In a radio receiver—the circuit. The circuit, Erla knew, must be the foundation of finest possible radio. So Erla first evolved those circuits which have ever since been rated inherently more powerful, tube for tube. Today’s trend clearly indicates that Erla Supereflex may be selected in full confidence of continued pre-eminence.

That these fundamentally superior circuits are also easier to construct, with utmost economy, is another Erla attainment, made possible by the Erla CIR-KIT. With CIR- KIT you yourself can construct Erla Supere- flex circuits from genuine Erla apparatus, specia'ly designed to assure most efficient functioning of Erla Supereflex principles. Erla CIR-KIT supplies everything needed, in a factory-sealed carton, sold under war- ranty. Erla Synchronizing Transformers, Erla Miniloss Condensers, Erla Pinecteton Rheostats, Erla Cushion Spring Sockets, Erla Tested Crystals, and all theother matchless Erla units are provided. You can assemble them with perfect results virtually guar- anteed by full-sized blueprints, drilled and lettered panel, stenciled baseboard, precisely locating every unit and connection. There is no soldering, thanks to Erla Solderless Connectors. Pliersand screwdriver alone are needed to bring you the de luxe radio of Erla Supereflex circuits, at lowest possible cost. Erla Push-Pull Transformer is exclusive in cove design and shielding. Indispen- sable for safe operation of high resistance loud speak- ers under full power. $10 pr.

Only the special spring arm, the perfected bearing and winding of Erla Precision Rheostats permit such supersensitiveness. ingle- hole mounting. Price, $1.10. Electrical Research Laboratories Dept. S, 2500 Cottage Grove Ave., CHICAGO and most positive contact, ms ERLA $25.00 in PRIZE The Saw Sold on cose eae Guarantee Backed by a guarantee of satisfaction we have built the largest business in small bench machines in the World. BOICE-CRANE JUNIOR SAW This sturdy precision built machine will saw, sa: miter, rabbet, tenon, and many other operations with ease and accuracy. Saws 14” stock. Driven by % or %h. p. motor attached to any light socket. { Write for Descriptive Catae log on Bench Machines, Jointers and Band Saws. W. B. & J. E. BOICE Dept. P.S. 1 A, Toledo, Ohio

Neatest, most convenient in form, Erla_Autogrip 2- y Phone Plugs assure smoothest connection of tips

See top of page 8 in front of book for details.

‘. January; 1925

Distinctive Colonial ~—a Kanne Constructed at Small Cost |? THE porch of your home is one that would be improved by a so-called Colonial light} you can make the lamp yourself at'a;/fra¢tion of the price that a design of corresponding distinction and decorative quality would cost in an ex- clusive electrical shop. The materials needed are of the sim- plest — sheet iron of about No. 20 gage; an 8 by 8 in. sheet of tin for the reflector; small rivets; a fewsmall round- headed machine screws with nuts; a sheet of window _ glass large enough to cut the seven lights required;

= ' BENDON <__—_—_--- —— = THIS LINE m "a | iC S| fe oe - - ee a A 3 REQ. r = 4% r (ee < it 4R ma Sour - © REQUIRED we REQUIRED ve

— em TIN a —, = ‘s pagan

ie The completed lamp and detail of parts a piece of 34-in. pipe, 1 in. long, fitted with a setscrew, and a piece of 3¢-in. pipe, 14 in. long, threaded at each end and fitted with a crowfoot and standard elec- tric-light socket. The hexagonal glass bottom is held in place by small 1%-in. angles; the side lights are fastened by simple clamps, each of which consists of an angle, a stove- bolt and an ornamental rosette. The ceiling canopy is supported by the short length of 34-in. pipe, which is slipped over and fastened with a setscrew to the main pipe. The ironwork is painted a copper, color with burnt umber to which has been added asmall amount of Venetian red.—

** Largest Makers of Small Bench Machines in the World**

WILLIAM J. EDMONDS, JR.

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31.

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1995 |: °° January, 1925 ~ POPULAR SCIENCE MONTHLY 107 Write today for your free copy of hat z Ward’s New Radio Catalogue Tested and guaranteed Radio equipment sold with- out the usual Radio profits sim- ARD’S Radio Department is head- ed by experts who know and test everything new. Who know by experience what is best—what gives the best service. Our catalogue is prepared under their supervision. It shows all the best hook- ups, everything in parts and complete sets —so simple that you yourself can install them in a short time. Headquarters for Radio Today Ward’s is serving thousands upon thousands of Radio fans who have written for our catalogue, who have been surprised to see how low in price the standard Radio equipment can be sold without the usual ‘*Radio Profits.”’ DON LINE . a a al oe x S th You, too, can profit by writing for a free is Warns Radio Catalogue is a big 68- copy of Ward’s Radio Catalogue. If in- page book—a real reference volume on terested at all in Radio, you should write - quality Radio Equipment. In addition for this hook. See for yourself the savings. to descriptions of sets, parts and hook- ; ups, much matter of general interest to Our 53 -Year-Old Policy 4 every radio fan is included. The book ; PA will prove fascinating to the confirmed For 53 years we hav e sold quality merchan- arts radio enthusiast as well as to the be- dise. We never sacrifice quality to make a ginner. low price. In buying ~adio Equipment at - Ward’s, you are buying from a house of yoo proven dependability. Address our house d elec- nearest you: Dept. 5-R, held in 1e side s, each Mi ‘ESTABLISHED 1872 nee ontgomery Ward &Co. by the hich is e etscrew The Oldest Mail Order House is Today the Most Progressive aly ie Chicago Kansas City St. Paul Portland, Ore. Oakland, Calif. Ft. Worth is bee ; . red.— eel © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31.

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I ean From Big Investors How to Become Independent in Only a Few Years on a Small Salary “For years I thought it ‘money-luck’ by which big investors built fortunes,” a successful investor wrote recently. ‘*Then I was promoted to a position that brought me into contact with the confidential affairs of my employers. I was amazed to discover the secret of their investing—the legitimate methods they had used to build up fortunes in a surprisingly short time with safety!"’ These remarkable methods are fully described in an important book called ‘‘Ali Baba’s Cave Redis- covered,’’ It outlines for you the most successful plan ever developed for the scientific accumulation of money. It tells you how to accumulate $10,000, $25,000 or even $50,000 in a certain length of time. It shows you how you can create a good sized estate through investing in Forman First Mortgage Real Estate Bonds—all without risk or speculation of any sort. Mail the request blank for your copy. It may change the whole course of your life. GEORGE M. FORMAN & COMPANY 105 W. Monroe St., Dept. 831, Chicago Pershing Sq. Bldg., New York 40 Years Without Loss to a Customer MAILED FREE Fi aaa: apere- Ese Real tate Bonds George M. Forman & Company 105 W. “Monroe St., Dept. 831, Chicago, Ill. Please mail me, without cost, or obli ation, a copy of your Free book, ‘‘Alj Baba’s’'Cave Rediscovered.” ees ts ne ee ee ee puvigecabipouss ~ tee ular, a ee POPULAR SCIENCE MONTHLY ' January, 1925 The Home Workshop Hood Conducts into Chimney Dust from Furnace Ashes NE of the dustiest and most dis- agreeable jobs around the basement heating plant is the removing of the | ashes from the furnace to the ash con- tainer. The hood illustrated is a‘simple ‘and efficient method of eliminating practically all of the dust. When you are ready to remove the ashes, place the ash bucket under the hood and open the damper in | the pipe directly above the hood. Close | the draft damper to the heating plant. How the hood is built and connected with the smoke pipe of the heating plant The ashes then can be shoveled unhesi- tatingly into the bucket; arises from them is sucked by the draft | out through the smoke pipe. The hood can be cut out of a piece of | light gage galvanized or sheet iron about | 40 in. square. The edges may be welded together or fastened by a small strip and | rivets. Ten feet of 14 by in. strap iron is cut into four legs of equal length and riveted or bolted to the hood. A damper section of ordinary 8-in. | stove pipe of proper length connects the | hood with the smoke pipe of the heating | plant. When not in use, the ash damper | is kept closed.— WILLIAM F. SANDMANN, Indianapolis, Ind. Preventing Canvas Belts from Slipping on Wooden Pulleys HENEVER canvas beltg run at high speeds on small pulleys, such as are found frequently on threshing machines, corn shellers, hay bailers, and other farm machinery, there is always more or less slip- ping. This is due to the cushioning effect of the air. The air cushions will not form, how- ever, if 14-in.-deep grooves are cut around the surface of the pulley, by holding a saw against it, as shown, at intervals of 1 or 2 in., and holes are bored through the pulley from end to end so as to inter- cept the grooves. Through these channels the air will escape.—GrorRGE MCVICKER. Saale oS = VENT HOLES Vents prevent forma. tion of air cushions the dust that | Clarity 2 Tone mane Kellogg Transform rh i a | HE repro- duction of the highest tones as well as those of thelowerextreme of the scale, with faithful, pure quality is essentially the spirit of Kellogg trans- former design. The lover of better music searches for a rendition simulating the original or- chestra. The ringing tones of brass, the mellowness of wood, the shrill of wind and the fan fare of reed, all in their in- dividual expression. The Kellogg transformer accomplishes this to a wonderful degree because of its perfect magnetic properties accomplished with the silicon steel laminations with- out punched holes This feature, distinctly Kellogg, elimi- nates losses to a greater degree than could be otherwise obtained. A transformer is as good as its absence of losses, Plainly marked terminals, brass shielding, moulded Bakelite tops, perfect | finish, are further quality and design expressions. | Amplify your pleasure with perfect amplifiers. USE—Is the Test & No. 501—4"% to 1 No. 502—3 to 1 © ' Equally efficient. Price $4.50 KELLOGG SWITCHBOARD © SUPPLY COMPANY 1066 W. Adams St., Chicago, Ill. i | | Big Value for 10 Cts. 6 Songs, words and music; 25 Pic- tures Pretty Girls; 40 Ways to Make oney; oke Book; 1 Book on Love; 3 ae Book; Book Letter Writ- 1 Dream Book and_ Fortune Teller; 1 Cook Book; 1 Base Ball Book, gives rules for games; 1 Toy Maker Book, Language of Flowers; 1 Morse Telegraph Alphabet; 12 Chemical Experiments; Magic Age Table; Great North Pole Game; 100 Conundrums; 3 Puzzles; 12 Games 30. Verses for Autograph Albums. All the above by mail for 10 cts. and 2 cts. postage. Fine Tone $2 Oo ae instruments derful new cop grighted Bde of teaching note muste by mail fo frat puoi in eae locality we will give free a S28 rb Violin + eer ulel si. — jan-Guitar Uku Cornet or Banjo- Guitar abeo- doli in. gs - natn. i Very small charge for a “only. +, Four lessons will Seach yoa Sa, pieces. Over 100, wove suscegarel plagers. We Compl olen Devt. nt” Mo sbligation: Slingeriand ‘School ‘of Music, 1815, = St. Chicago, tli. tS] This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31.

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1925 D ¥ January, 1925 aS (CELORON #2 BAKELITE RADIO PANEL Size 7 x 12 MANUFACTURED BY DIAMOND STATE FIBRE COMPANY BRIDGEPORT (Near Philadelphia) PENNSYLVANIA, U. S. A. MAKERS OF CELORON - Diamond-Fibre -VuLcawooD Offices in Principal Cittes tN CANADA. DIAMOND STATE FIBRE COMRBANY, OF CANADA, LTD. TORONTO, CAN, Made aad Priend a U. 6 A POPULAR SCIENCE MONTHLY How to Work and Finish centers of holes through the paper ta the Celoron panel witha pointed instrument. in drilling can be done 2 carpenter's brace or a breds« drill, but. metal-cutting twist drills id be used, not inary in to drill from the front wet the a foc! rit the rubbing all done in one direction, not with a circular motion. Wipe off the panel with an oiled cloth. Will not soften with heat or deteriorate with age uild your set around Celoron Celoron is accepted as the standard insulating material by leading radio and electrical equipment manufacturers. It is the choice of more than a million radio fans. SE a Celoron Panel in the next set you build. Insist on it in the set you buy. The distinctive characteristics of Celoron are its mechanical strength, waterproof qualities, high insulating properties and machinability. Tests have proved that it is the ideal insulating ma- terial. Celoron Panels do not soften with heat or de- teriorate with age as do rubber and composition panels. They do not split, warp, or discolor. They never lose beauty or insulating properties. The more you expect of your radio set the more you need a Celoron panel A Celoron Panel gives you thorough, leak-proof insulation. It guards your instruments against Diamond State Fibre Company ® Bridgeport, Pa., and Chicago, III. Branches and Sales Offices in Principal Cities The oldest and largest manufacturer of vulcanized hard fibre and laminated bakelite materials in the world loss of precious electric current. It improves the appearance of your set. It helps you get the best possible results from your radio hook-up. Celoron Tubing —Celoron tubing has all of the insulating qualities of sheet Celoron. It is used extensively by manufacturers of the best radio instruments. Coils wound on Celoron tubing hold their shape and give the most durable service. Celoron tubing is made in all sizes and diameters. Celoron comes in eight panel sizes and in sheets, rods and tubes. There are four beautiful finishes —gloss black, a dull mat black, mahogany and walnut. Send for FREE booklet We have prepared an. interesting booklet, “Getting the Right Hook-up with Celoron,” which contains many helpful:sug- gestions for building and operating a radio set. Send for one today, giving your dealer’s name and address. Wherever chimneys smoke and wheels turn, there are countless mechanical and_ electrical uses for Celoron and Diamond Fibre. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS, See page 31. CrioroN - ‘CrroRON SFANPORT RADE PART sales easier. 109 When you buy a kit, when you build a set, mount it in the first and only bake- lite cabinet —the new Vul- cawood Cabinet. It will furnish complete insula- tion. Its design and finish will give your set a snappy professional appearance. TO DEALERS: Let your customers know that you handle Celoron Panels. This handsome dis- play rack gets attention—it talks for you—it makes Write for information regarding it. Rae aie seg ged ds

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ee Hf 110 POPULAR SCIENCE MONTHLY January, 1925 USE ONLY A FIBROC PANEL F you want all of the good features a panel must have to be absolutely satis- factory. Get these features in FIBROC-BAKELITE PANELS: —efficiency High dielectric strength assures freedom from distortion. —strength Though lighter than aluminum, FIBROC is stronger than steel of equal weight. —beauty FIBROC-BAKELITE PANELS are made in black or mahogany finishes with either a high lus- trous polish or velvet finish that adds real beauty to the set of which it is a part. —ease of working FIBROC-BAKELITE PANELS can be punched, drilled or cut without chipping. They are readily engraved. They will not warp or cold flow. FIBROC-BAKELITE PANELS are sold in standard sizes, each in individual envelope, by better radio dealers. Ask for them by name. FIBROC BAKELITE is also sold in the form of SHEETS—RODS —TUBES © FIBROC INSULATION COMPANY VALPARAISO INDIANA The Home Works A Tandem-Steered Hill Racer By Dale R. Van Horn HIS racer is de- signed for either winter or summer use on hills. With unusually wide beam, it ‘“‘hangs”’ to the ground and is so light that one boy can pull it uphill with ease. But perhaps its chief charm lies in the fact that it is steered somewhat after the manner of huge city fire trucks with two steering wheels. The body is built of wooden strips and the frame covered with painted canvas or light-weight tin. The snug cockpit is neatly inclosed. If you wish, you can attach an air propeller in front. Any boy handy with ordinary tools will find no difficulty in its construction. Here is a list of the materials required: Two % by 3 in. strips, 11 ft. long. Two 1% by 2% in. pieces, 3 ft. long, for axles. Two 1% by 3 in. pieces, 2 ft. long, for bolsters. Four wheels from 16 to 20 in. in diameter, either all of the same size, or two pairs. Two wooden disks or other wheels for steering. Two broomsticks. Four pie-tins, all of the same size. Four wooden disks 1 in. thick and 1 in. smaller than the pie-tins. A quantity of tongue-and-groove wainscoting or ceiling boards for flooring. About 15 ft. of sash cord or equivalent rope. Two in. bolts, 64% in. long, with washers. Four lagscrews 6 in. long, with short pieces of gas- pipe to fit the wheel hubs unless the wheels already are provided with extra long hubs. Sundry boards for cleats, seats, brake and the rest of the frame. 100 ft. of galvanized wire. Enough canvas or tin to cover the frame. WHEELS FROM 16°TO 20° DIA HINGES BRAKE BOARD PROPELLER UNVIRE WIRE FLOOR —_ “he —l-4" + B14 front of the cockpit, and the third to fit back of the rear seat. These need no exact dimensions, though they should be slightly higher than they are wide. The detail on the next page shows how they are built up and assembled in place. Now we are ready to truss the wires. Run one wire along each side, attaching the ends in screweyes as indicated and running them through other eyes turned into the cockpit frames, about 10 in. from the floor. These wires later form the side of the cockpit. Through other screweyes, run wires from the tops of the frames down to the side pieces near the seats to counteract the pull of the several wires run from each end. The two steering-wheels are mounted upon vertical broomsticks, which termi- nate just under the floor in special V-shaped pul- leys made from the pie- tins. The steering-cord is placed about the pul- leys, and the ends, after being drawn tight, are _ Secured in stout screw- eyes set on the back of the front and the front For winter use runners are substituted for the wheels of this The top and side views appear above speedy racer. . The two 11-ft. side strips of the main frame are held apart at the back and front by flat blocks. That at the rear is a triangular block 2 in. thick, 8 in. long and about 5 in. wide. The side strips are nailed to this with their ends flush. The other ends of the strips are nailed to an- other 2-in. block 12 in. wide and 6 in. long. The sides of both blocks should be curved slightly to fit the general curve of the sides. This can be seen in the accom- panying top view of the car. One axle and one bolster piece, after being bolted together, are attached 18 in. from the front; the other pair are fastened 3 ft. from the back. The bolsters are held by nails driven through the side pieces. Build three frames from 1-in. material, one for the front, another for the dash or of the rear axles, 4 in. from each end. To make the pulleys, set the tins in pairs, bottoms together, and solder them. Cut wooden disks and place one on each side; then drive through them nails long enough to reach through the tin and the two disks. Be sure to close the bottom of the groove clear around with solder so the cord will not force them apart and bind when in use. To insure a positive grip between pulleys and cord, rub the cord with belt dressing. Locate the centers of the pulleys and with an old wood bit, slightly smaller than the broomsticks to be used, bore holes through them. Use glue or two nails, driven at an angle, to lock pulleys and shafts. Now spread the frame sides until they are two feet apart, midway between the ends, and nail.on the floor boards, leaving spaces for the seats, which are built and (Continued on page 111) © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31

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= FRAME FOR January, 1925 ‘Coantinued Sei peti 110) asserr bled as indicated by the seat detail. This done, bore holes for the steering shafts through the floor at the points | indicated and midway between the sides, and support the lower ends by means of wooden strips with a hole through the lower cross piece for the lower end of the ‘| broomstick and with the pulleys between this and the floor above. Nail to the sides, then truss with short wires as indi- cated to offset the pull of the cord. The steering columns should be verti- cal. The steering wheels may be old coaster wagon wheels or wooden disks cut for the purpose, bored and glued or nailed on the upper end. Now finish placing the wires by running them from the ends to the curved upper portions of the cockpit frames, using small staples to hold them. These wires EE Zz. DETAIL OF SEAT ‘COCKPIT ENDS = == = ——— = a — —— == WASHERS A ~ ¢* x24 ei PIPE DRIVEN INTO HUB }~—_—_—— 2'-6" —————_>| Details of the brake, steering mechanism, frames, runners, and wheel assembly give the desired curve to the canvas or further support the tin, if used. Build and attach the seats, and provide the brake, which is made by cutting out a portion of the floor just in front of the rear seat, cleating and hinging it at the forward end and nailing to this trapdoor a short board. This board is held horizon- tally by aspring attached to the rear cock- pit frame. The spring also keeps the hinged portion of floor in place. Yet ata moment’s notice, the rear rider can bring the racer to a complete stop by stepping on this portion of the floor. Lay the covering in three sections. Cover first the front, placing the material on and marking where the cuts are to be made. Then fix the two side pieces; finally complete the rear. If tin is used, the edges can be crimped over the wire edges of the cockpit; if canvas is used, the edges should be sewed tightly over it. (Continued on page 112) “The Saw Makers”’ POPULAR SCIENCE MONTHLY BUY GOOD TOOLS Make this year a S { ip uebakehebetarcral ND S SAWS FILES KNIVES STEEL SIMONDS SAW AND STEEL COMPANY iShicedelelebartiny elie Branch Offices in Principal Cities @ This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31. Established. 1832 eRe RIE TEE TAINO AES RP PIES REET ONS, AT A ai ak a — ~ feee > 4 momen ors arer Seer ee ee ee

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"112 13" x §' South Bend Quick Change Gear Lathe, $354.00 PRICE LIST POPULAR SCIENCE MONTHLY of Our Easy Payment Plan Popul allows you to install a SOUTH ar Sellers . BEND LATHE in your shop, by making one payment with the Sise of | Standard | Quick | order; the balance to be paid hehe | Se | Sw C- month by month, the amount de- pending upon the size of the Lathe. g WRITE TODAY for Catalog ee pee eee 1941.00 No. 82. It shows the complete 11"x 314'| 244.00 | 284.00 line of SOUTH BEND LATHES 13"x 4’ | 292.00 | 342.00 and Attachments and will give you full details of the EASY PAY- 15"x 5’ | 360.00} 415.00 MENT PLAN. 1 ’ a eee SOUTH BEND LATHE WORKS 16"x 8’ | 438.0C | 498.00 5/5 E. Madison St., South'Bend, Ind., U.S.A. 18" x10’ 656.00 | 721.00 SOUTH BEND LATHES OVER 31000 SATISFIED USERS $25.00 in PRIZES Swair'™ tion of cha: It holds its cha cre Idee will find this D battery = boon to } pose away with a great many noiscs 80 often blamed on * Mail your order today. “SEND NO MONEY Jast state number of batteries Banted and we will ship day order is PMs EXTRA OFFER: 4 batteries in series (96 | volts), $ Expresemee fue examining batteries. 5 | © | STORES S PECI A 509 S. State St., CHICAGO, U.S. A., Dept. P. S. 6 E | tera: RADIO For a limited time only, and to introduce this | | Our new 68-page INTRODUCTORY PRICE new and superior Storage “‘B’’ Radio Battery to | i the Putten owe are selling it for $3.50. Regular | Catalog will save you money a Price is $5.50. Yousave $2.00 by ordering | |) on brand new, fully guaranteed, nationally ad- W. A finer battery cannot be built than the | World Storage “RB” Battery turers’ and government surplus stocks, jobber (12 CELLS—24 VOLTS) ten million homes with Radio Sets—and to Sonn prospective oevere— she wortd Storare B’ s wW CcOo!.ce ono nom. , ? a. Sateen Denbeaeten ame tee (alt ine foe ee facturer’s costs. That’s why our catalog is will last for years and can be — at a negligible cost. And you save $2. ing no Eq uipped With A Superior Battery Solid Rubber Case Has heavy duty 21-8in. x 1 in. x 1-4 in. plates and plenty of acid circu: come Extra heavy glass jars allow ready observa- and prevent leakage and scenes ze of current. hile idle, at wg coe vol WORLD 1 BATTERY COMPANY Makers of the famous World Radio **A’’ Storage Battery 1219 S. Wabash Ave., Dept. 80, Chicago, Ill. SAVE $2.00 BY ORDERING NOW? LARGEST RADIO STORES IN AMERICA vertised radio apparatus. We buy up manufac- and dealer bankrupt stocks, etc. Our enormous ts ntl buying power permits us to pay spot cash and s— tless mil- a * Rat- get rock-bottom prices—even way below manu- crammed with thousands of wonderful radio bargains. That’s why we GUARANTEE to save you money. itage. ong distance receptio with order. Send yourorder | January, 1925 | white makes the numbers stand out with | in each truss wire so that any slack can be | taken up without delay. | 2 by 4 and mount it on a shaft supported | grasp the steering-wheels. To turn to the _ wheel to the right, while the rider to the | winter use. Build these in pairs, con- | nected at the top of each end of the run- | you have tested it out, protect all parts | _and held there, the racer swerves from its | path, then continues in a straight line but _ with the machine pointing to the left. | with a coat of paint. Keep the steering | cords tight and lubricate the steering Old Caleater Scesidan Figures for House-Number Plate N ATTRACTIVE house-number plate can be made at little or no cost from a 3 by 5 in. piece of glass and large black numbers, about 214 in. high, cut from a discarded business wall cale#dar. Stick the black faces of the figures to the glass with transparent glue or mucilage. When /\ ary, coat their “|= packs with the -— same adhesive, or, a == better yet, shellac. PAPER oa! Next, apply one or (GLUE ¢ ON BLACK SIDE) more coats of . White or some light-colored paint over the entire back of the glass remem = - Sheet. Figures are black Fasten the plate against white to the building with four uphol- sterer’s brass-headed tacks, driven in until the heads barely touch the glass. The carbon in the printer’s ink, backed by the paint, will remain black for a long time, and the combination of black on exceptional clearness.—F. W. B. Tandem-Steered Hill Racer (Continued from page 111) It will be well to provide a turnbuckle If you wish a propeller, cut it from a as indicated in the side and top views. It should have at least 6 in. clearance above the ground. A propeller only 2 ft. in diameter will spin faster and weigh less than the one shown. Two heoks should be set in the front and a 20-ft. tow rope with rings in each end kept back of the rear seat. To use, two riders take the seats and right, the front rider turns the steering- rear turns his to the left. All sorts of stunts can be accomplished by this racer. For instance, when both steering-wheels are turned to the right Of course you will wish runners for ners by cross pieces. Bore holes through the top edges near the center for the axles and put these on in place of the wheels, using the same lagscrews. When the runners are used, it will be great sport to build a smooth snow track down some steep hill so that it terminates on the shore of a lake or pond. Then, by careful manipulation of the steering ap- paratus, great distances can be covered. As soon as the racer is completed and columns well with hard oil. ee ae Sapa a ee eee © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31. PEER IRI EIT IE TB ‘ . —

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January, 1925 The Home Workshop Useful and: Attractive Benches Constructed at Little Cost MALL benches or stands, that serve many purposes in the home may be made quite easily. I have constructed two attractive benches from a single long board 11% in. thick and 12 in. wide. The way these were made is indicated in the accom- panying illustrations. The four legs can be cut out in each case from one width of the board with a minimum of sawing. The tops are made fe 24" Kft oe av" 15" Wake of bth = 2" The pieces for making this bench are cut from a single wide board without waste simply by sawing the board to length and cutting off the corners, the upper edges being rounded off smoothly. The benches are put together with glue and wood screws and then are painted neatly. In this case the benches were first primed with one coat of flat white paint he 2" + 616-21 oe A low bench, which embodies another type of strong yet exceedingly simple construction and then the ornamental designs, pre- viously drawn on paper, were traced on | them. Several 10-cent cans of different colored paints provided the coloring. The surface was given a final coat of clear varnish.—H. S. TRECARTIN. Straightening Dented Tanks N VARIOUS occasions I have straightened copper floats and re- moved dents from sheet-metal tanks simply by soldering on a number of wires, . as indicated and = WIRES pulling the vessel amy SOLDEREDON _ back to its original shape. After the _ Straightening is * completed, it is a simple matter to remelt the solder and remove the wires.—N. G. N. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. POPULAR SCIENCE MONTHLY 111 Spiral-Ratchet Screw Driver Price $2.50 The improved positive lock-nut permits auto- matic driving or draw- ing; will instantly con- vert it into a ratchet screw driver, or will lock it rigidly for use asa plain screw drivete Beveled edges prevent finger-pinching. ; Automatic Y screw driver | a! | perfected with 1 new features : HIS screw driver sinks a screw with the ; least possible effort. The improved posi- }) tive lock-nut permits automatic driving or , drawing; will instantly convert it into a | ratchet screw driver, or will lock it rigidly ’| for-use as a plain screw driver. Beveled ' edges prevent finger-pinching. } The spiral nuts and the steel spiral are «i made of hardened steel, milled at a twenty ; degree angle. Thus this tool withstands unusually severe strains. A conveniently located shifter knob con- trols the ratchet mechanism. Three tool-steel blades—hardened, tem- pered and polished—are provided. Length extended with blade in place, 18 inches. Length closed, without sarees 10 inches. Weight, 14 ounces. Steel spiral nuts and steel spiral, machined at a 20° angle. What other tools do you need? The Goodeli-Pratt Catalog No. 15 shows the entire line of 1500 Good Tools—many of them particularly adaptable for the home work shop. Write for a copy. GOODELL-PRATT COMPANY » GREENFIELD, MASS., U. S, A. Aochimithe Makers of Mr. Punch GOODELL-PRATT 1500 GOOD TOOLS © See page 31.

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SPEED! and Adaptability You appreciate the way Snap-On Wrenches work— because Popular Science readers know the value of good tools. Get a set for that car of yours —for your truck, motor boat or any machinery you have to keep in repair—and enjoy the tremendous satisfaction of | working with wrenches that will run on or off any nut— anywhere—in the hardest-to- reach place—in jig time. You can hold in one hand all the Snap-Ons you need—Snap- On engineers. have selected the exact wrenches for each stan- | dard make of car—no more or | no less than are absolutely | needed—giving you the maxi- mum in wrench service at a minimum price. You can see Snap-Ons in action in almost any garage Look for the name—without it no wrench is a genuine Snap-On s © Ofap-on Socket Wrenches Snap-On Wrench Co., Mfrs. Milwaukee, Wisconsin eo @Taeeee ee ee eS See ae ee ee ee ees aw ae as & DISTRIBUTORS MOTOR TOOL SPECIALTY CO. 14 E. Jackson Bivd., Chicago Gentlemen: Please send me full particulars about Snap-On Kit te ea car. (If interested lo in Master Mechanic’s Kit, check here weer eee eee eee ee eee ee eee eee eee eee ee eee eee ee eee ee ‘ POPULAR SCIENCE MONTHLY January, 1925 Priscilla Sewing Cabinet Is an Always Welcome Gift FroR your next home workshop under- taking, why not try building a Priscilla sewing-box? It makes an attractive piece of furniture for the sew- ing-room, and being small and light, it can be carried into the living-room, sun porch, or any place where the always Complete List of Blueprints As: 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 250 Fourth Avenue, New York GENTLEMEN: ; ; Send methe blueprint, or blueprints, I have underlined below, for which POND so nesc sd a warecie or cents: No. Title Price eS a ee ae ee. 25c 2. Smoking Cabinet............... 25¢ 3. Book Trough End Table......... 25¢ eS ee ee 25c 6. Two-Stage Radio Receiving Set. .25c 8. Shaving. Cabinet................ 25c 9. Arbor with Gate and Seats....... 25c ce eee eee 25¢ 11. Bench and Tilt-Top Table....... Zoc 12. Electric Washing Machine....... 25c Se ee eee 25c 14. Toy Train, Horse, and House....25c * 15. Home Workshop Bench.......... 25c 16. Inlaid Radio Cabinet............ 25c 17. Cedar and Mahogany Chest...... 25¢ 18. Telephone Table and Stool....... 25c 19. Grandfather’s Clock............. 25¢ ee Se a. 25c 21. Colonial Writing Desk........... 25c 22. Girl’s Cabinet and Desk........ 25c Cy 25c ee i 25c 25. Sailing Outfit for Canoe......... 25c 26. Baby’s Crib and Play Pen....... 25c 27. Kitchen Cabinet Work Table... .25c 28. Pullman Play Table............ 25c 29. Toy Tea Cart, Garage, etc....... 25c 30. Tool Cabinet, Bench Hook, etc.. .25c 31. Priscilla Sewing Cabinets........ 25c 32. Chinese Game Table............ 25c 33. Pullman Dining Alcove.......... 25c 34. Trellises for House and Garden. . .25c 35. Simplified Radio Cabinet........ 25c 36. Rush-Bottom Arm-Chair........ 25c 37. Simplified Bookcase............. 25c SOs MUOTCOEN DOWNS 00 ce nccecc cscs 25c ES Stee Re Tiss ad Uh ae Cie sere eee (Please print) an seas ss Seige ene Rabe sos seuss EIN ec i lo esas Se sw is Sle accumulating odd jobs of needlework may be done most comfortably and con- veniently. Generations of use in American homes have placed the stamp of approval on the Priscilla cabinet. The complete working details and bill of materials for a sewing cabinet of this type are contained in Home Workshop Blueprint No. 31, listed on this page. H. Caldwell, of Toronto, Canada, used this blueprint in constructing the cabinet illustrated. He writes: . My wife, who has wanted one of these for some time, is quite pleased with the result, and declares that it has not a bit of the ‘“‘homemade” look. I am quite proud of this job myself, as it required a little more care than anything that I have yet made, though I would not call it at all difficult. I used walnut, and for a finish filled with a dark filler, gave two coats of shellac, rubbed down with felt and pumice, and then waxed. This gave a very fine satin finish. The new blueprint for this month gives full size details and bill of materials for the table illustrated on page 89. Lathe Grinding Attachment Made from Odds and Ends 1* YOUR home workshop equipment includes a small motor, it can be arranged for plain grinding on a lathe. The motor is mounted on a slotted steel plate, which is clamped under the tool- post washer. The wheel is carried in a special bracket with a shank to fit the toolpost. A front-wheel bicycle bearing is used for the spindle bearing. The outer casings Ril! — i e FACEPLATE 7 rt Sa \ lh » FELT WASHER DUST COVER Grinder in use and details of the spindle, which runs in a simple bicycle bearing co are made from steam pipe, counterbored to receive the ball races. The ends of each casing are turned true in relation to the center line of spindle. The dust caps shown were found in the scrap pile. The shank is forged and drilled to re- ceive the bearing, which is brazed in place after it has been set square and clamped in position. The wheel spindle is driven by belt—in this case a rawhide belt lace. Adjustment of belt and wheel is made by means of the toolpost screw. The spindle may be made longer, for in- ternal grinding, if desired. If a motor must be purchased, it would be better to buy a regular grinding attachment. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31.

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January, 1925 The Home Workshog Using Dowels and Wedges to Make Difficult Repairs por in woodwork that are especially difficult to fasten securely can be held in many cases with dowels and wedges. This method of repair is illustrated in the accompanying drawing, which shows how I have fastened bicycle rims that had split at the joint. This is a fairly common repair, but is rarely made permanently and satisfactorily. To repair a bicycle rim in this way, remove the wheel, take off the tire, and loosen the spokes directly over the joint. Hold the rim in a convenient position, force apart the leaves, and apply a thin film of glue over both surfaces. Place the joint in a vise so that about two-thirds of it is above the level of the jaws. Drill two holes of 5/16-in. diameter at such a point that they will all but penetrate the inside concave part of the rim. The Fastening permanently holes should be 3% a split bicycle rim in. from each end of the joint. Have ready two dowels cut with a dowel plate or turned. Besure they area snug fit. ..They should be 4 in. longer than is required. Through each end of these make two saw cuts parallel to each other and about 1% in. deep. Now make four wedges 34 in. long and 5/16 in. wide. These should be as thick as the saw cut at one end and 1/16 in. wider at the other. Apply glue to the holes through the joint and drive the dowels through the holes until they project equally on both sides, with the saw cuts parallel to the spokes. .Glue the wedges and drive them into the saw cuts. Allow the glue to dry for at least 12 hours and then cut off the projecting dowels and smooth the ends, which may be painted to match the rest of the rim. Retighten the spokes and assemble.—I. H. C. Blotting-Paper on Bottle Neck Prevents Stains on Labels HATEVER care is exercised in pouring chemicals from bottles, a drop or so of the solution occasionally will find its way over the lip of the bottle and destroy or badly discolor the label. By tying or otherwise fas- tening a piece of blotting- paper around the neck of the bottle, any drops that flow Any gverhow is ab over the lip will be absorbed. This prevents the dis- coloration of either label or shelf. POPULAR SCIENCE MONTHLY | | & SHARPE [TOOLS —For the Motor Mechanic Here is an Inside Micrometer that is new. It has a clamp nut that locks the spindle at any reading. The No. 264 takes cylinder bore and other inside measurements from 2” to 8’ by thousandths with ease and precision. —For the Shop Mechanic and Toolmaker A tool kit isn’t complete without one of these handy Adjustable Squares. Blades are interchangeable and adjustable to any length. You will find the reversible blade feature of the Brown & Sharpe No. 554 gives it an added handiness. Another new tool that proves its worth is Brown & Sharpe Thread Tool Gauge No. 577. Adjustable, for cutting tools, from a sharp “V” toa 1” flat. Made with three differ- ent angles—60°, 55°, or 29°—and remarkably inexpensive. —For the Apprentice and Home Mechanic Set of Tools No. 847 is one an apprentice or home mechanic finds that answers his requirements. ‘They have been especially chosen for the requirements of the beginner 4] or home mechanic. This set represents an :: jj outfit of high quality tools at a moderate~ ' | outlay. Tools are fur- nished in a neat, felt lined, leather case which helps to protect them from injury, dust and moisture. Our new No. 29 Small Tool Cata- log lists all the above and over 2000 other tools. It’s a buying guide every tool user ought to have. Copy sent on request. © Brown & Sharpe Mfg. Co. Providence, R. I., U.S.A. ‘Standard of the Mechanical World ’’ © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. . See page 31.

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POPULAR SCIENCE MONTHLY Did you ever notice that the fellow who turns out the professional looking jobs—is a crank about the pliers he uses? Next time you’re around, drop into your hardware store and get the feel of a pair of Klein’s in your hands—then you’ll know. They’ve been standard in big electrical companies for over half a century! Mathias EIN & Sons 5 r[FAHLE wis. minutes — non-explosive — Burns alcohol. Reddy Hot Soldering Outfit consists JOBBERS AND DEALERS: ‘Vrite or wire for attractive Reddy Hot proposition an samples. Display carton of 12. nace for which I enclose $1.50. My dealer’s name is_--........-.-..- TE GG, cncncnccaweecsatsonncs Seer eta Sac ccas esto For Perfect Conductivity :. 2 It is now possible for the im Radio amateur to get tight, clean jointsin his home solderingthat make the per- | ect conductive path necessary in radio work. | Mr. E. D. Fahlberg, former Professor of | Metallography at Wisconsin University and Metallurgical Engineer with Western Electric Co., has developed Reddy Hot, the complete home soldering furnace. Heats iron in two Reday HOT Soldering Furnace and Tested Supplies soldering copper, detachable handle—Fine soldering connie Flo Household Solder—Can Reddy Stik non-corrosive Soldering Flux for Radio—Can Reddy Prest Sal Ammoniac, keeps tip clean—Can Reddy Rub Abrasive Tape. Complete directions. Ask your dealer. If not obtainable we will send di- rect, for a short time only, on receipt of price. E. D. Fahlberg Mfg. Co., Madison, Wisconsin E. D. FAHLBERG MFG. CO., Madison, Wisconsin Send me prepaid one Reddy Hot eee ou = In Licensed by ant “Penden, Radio Manufacturer EUTRODYN eae Other Patents Pending ed sn bey 107 Reg.U.S Pat. Off > é denatured Ask your dealer to show you a Howard 4 and 5 Tube Neutro- of: Large dyne Receiver $450 Write for : folder and wiring diagram. 4 HOWARD MFG.CO. 467 East Ohio St., Chicago January, 1925 Workshop How to Duplicate a Rare Table (Continued from page 89) The exact sizes of each piece are given in the following bill of materials, each item being lettered to correspond with the drawing on page 89. The dimensions are given in inches and the wood is either mahogany or walnut, except as otherwise noted. A Center or main top, 7 by 22% by 32, 1 required B Table leaves, 74 by 13 by 32, 2 required C Legs, 2% bv 214 by 281, 4 required Drawer rails, top, 4% by 114 by 16, 2 required E Drawer rails, bottom, % by 2% by 16, 2 required F Drawer fronts, 74 bv 4 by 16, 2 required G Drawer sides or ends, 14 by 4 by 13 \%, 4 required H Drawer backs, % by 3% by 15 2 required I Drawer bottoms, 14 by 13 by required J Side rails, top, 7% by 614 by 25, tenoned both ends (244% between shoulders of tenons), 2 required K Table braces, 7 by 614 by 26%, 2 required (each piece will cut two braces) L Guides, top of drawers, 74 bv 14% bv 26%, whitewood, 2 required M Guides, bottom of drawers, % by 2 by 25%, whitewood, tenoned both ends (24% between shoulders of tenons), 2 required N Guides, bottom jrunners, 5/16 by 114 by 24, whitewood, 2 required O Stretcher shelf, 54 by 73g by 151% (doweled to legs), 4 required P Dowels, stock, %% in. diameter Q Table-leaf hinges, stock, 134 wide, brass, 6 required R Top fasteners, stock 14 by 34 by 14, iron 12 required —s ow wt ¥ plywood, 2 | S Drawer pulls, stock, brass, 2 required T Wood screws, iron. Two methods of making the drawer joints are shown, but dovetails may be used, if the builder prefers. The legs on the museum table, shown in the photograph, are round and tapered just above the foot and ornamented with reeding or flutes. This construction presents some difficulties and can be avoided by making the lower part of the legs square and tapered, with or without flutes, as preferred. The finishing of a piece like this is of the utmost importance. Stain the wood, fill with paste filler, either walnut or ma- hogany color, apply a wash coat of thin shellac and then build up a smooth sur- face with coats of either shellac or varnish, well rubbed with pumice-stone and oil or water or a very fine grade of the so-called “wet” sandpaper. A dull shellac finish with the addition of several coats of furniture wax is one of the -best for this piece. The table could be made of whitewood and painted or enameled, the flutes being colored deeply for contrast. In that case knobs may be used instead of antique pulls. Tightening Barrel Staves TAVES of dry wooden barrels may be tizhtened easily with a tool made from a broken hoe, as illus- trated. The offset allows the tool to be held away from the barrel at the upper end and this facilitates the work. The lower end has asmall bevel so that it will not slip off the hoop.—I. S. THOMSON, Richmond, Utah. Janu ever you oul ‘ Jt play neec card quir the in s port the the The SHUI pict oth diff car fro. for) Ru poi tha dov nee ape mo am @® This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31.

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January, 1925

The Home Workshop New Mirth-Provoking Card Game Made Quickly from Pictures By Capt. E. Armitage McCann N EW amusements are always in de- mand, both for big parties and quiet evenings at home. Here is a card game you can make yourself and spring on your friends as an entertaining novelty. .To make a set of cards for four or less players, six colorful pictures will be needed. If they are about 8 by 10 in., 10 cards about 24% by 3% in. will be re- quired for each picture. Arrange these 10 cards irregularly on the table and paste on them the picture in such a way that each will receive a portion of it, as illustrated. Then, with the corner of a razor blade, cut through the picture along the edge of each card. The set will fall apart with a piece of PICTURE PASTED OVER CARDS

PORTION OF PICTURE APPEARS ON EACH CARD Diagram showing how a large picture is pasted over 10 cards, and three completed cards picture on each card. Do this with the other five pictures, arranging the cards differently for each set. The game is played by shuffling the cards and drawing and discarding them from the pack. The person who first forms a complete picture is the winner. Rules and a system of penalties and points can be formulated along any lines that seem desirable. Use thin cards and paste the pictures down firmly. Sometimes the edges will need repasting after the cards are cut apart. The cards for the whole pack must be of the same size. If there are to be more players, have more pictures. The game may be made amusingly educative by substituting maps or historical subjects.

New Workshop Features MONG the articles scheduled for early publication in the Home Workshop Department are: Salem Chest of Drawers Simplified for the Beginner in Woodwork, A Linen Cab- inet Made from Packing-Cases, Re- caning Chairs, A Quebec Coaster, Am- munition Press for Snowball Battles, Alarm Clock in Neat Case Resembles Costly Chronometer, and Nail and Hard- ware Cabinet for the Home Workshop.

POPULAR SCIENCE MONTHLY

{ ELECTRICAL E Quip Ng Pes < ra, ae lll? No} Barty ry

iil i q Cg Type 6-D Broadcast Receiver Non-oscellating ~. Non-radiating ET nl f he sr el bi ay Mi iii ~ . 2oe? oe HE real, intrinsic value of the 6-D Receiver can be fully appre- ciated only by making direct, side- by-side tests with other makes.

= | SPECIFICATIONS Circuit: Two stages of tuned cadio frequency amplification, detecter and two stages of audio frequency amplification. Non-oscillating. Non-radi- ating. Astatic transformers used te minimize mutual induction. Tubes: Five in all. Jacks provided for either five or four tube operation. Such comparisons need not be con- fined to sets in the same price-class. The 6-D is the equal, in every de- tail, of many receivers priced $25, $50 and even $75 higher. Batteries: Either storage or dry-cells. Cables : Complete sct supplied for “SA” aud “B" batteries. Wavel engths : 200 to 600 me- ters, with uniform efficiency of reception, Aerial: 75 to x2 feet, single wire. Pond: Aluminum, with attractive crystal black finish. A "ee body capacity shield. Dials: Sunken design. Shaped to fit the hand and permit a natural position in tuning. Rheostats: Adequate resistance for all standard base commer- cial tubes. Condensers: Single bearing, low leakage losses. Sockets : Suspended or cushion springs which absorb vibra- Performance of the highest order, strikingly attractive appearance and moderate price—all these ele- ments of true worth are found in the 6-D. You will note its clarity and the full, generous volume. You will also observe the unusual sharpness tons. of tuning. And the finely carved, Cabinet: Mahogany, with dis- tinctive lines and high finish. Ample space provided for'*B’’ batteries, high finish mahogany cabinet will make a strong appeal.

Price $125.00 without ris) accessories. For sale by reliable dealers. BISEMANN -MAGNETO -CORPORATION General Offices: 105 Broadway; Néw York

coeTteR.oiT ° SAN FRAN CISCO ° CHICAGO

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31.

Page 86

POPULAR SCIENCE MONTHLY January, 1925 J oo Base Mounting ¢ 45° This is the MULTI-PLUG used by THE STANDARD SET CONNECTOR HOWARD, WORKRITE, ZENITH, MU-RAD and other leading set manufacturers. [NSTALL a Jones Multi-Plug and Cable on your set. A plug and cable is to the radio what the socket and cord is to the electric iron—a connector which is efficient, convenient, safe, and indispensable. EFFICIENT because battery, antenna, and ground wires can be connected and disconnected by a single operation. Seven confusing operations reduced to a simple one. It assures perfect contact and is simple to connect. CONVENIENT because it per- mits the moving of set anywhere without disconnecting wires. The eight foot cable allows batteries to be placed in basement or: other suitable place. SAFE because no live ends are exposed and center pin is keyed so that wrong connections are im- possible. INDISPENSABLE. You will know why only after testing out this plug designed to meet the de- mand for an inexpensive yet prac- tical and simple method of con- necting batteries, antenna, and ground. Order from your dealer or direct from HOWARD B. JONES - + + 620 S. Canal St., Chicago © Write for illustrated folder. ae Pld a Super Heterodyn — Xourseltand Save Money/ Experience the thrill of getting all the distant stations with a Super-Het built by yourself. It’s easy with the RECEPTRAD “KIT shown above. It contains all the essen- tial parts with complete instructions. From your dealer or by mail for the remarkably low price of $53.50. Smaller kit containing only the most essential parts $33. Either set will operate _ a loudspeaker on an indoor, outdoor or loop aerial pouBLeatiecron MULTIFLEX KIT The Perfect 4 Tube Circult—Loop Operating Uses four tubes. Two stages of radio frequency, a crystal detector and three stages of audio frequency. No station too distant to be brought in with clear volume. Assembled by anyone in a few hours. Superior to a 5 tube Neutrodyne. $29.50 Containing principal parts. $50 Including all parts. Blue prints of wiring diagrams of both circuits. Just drop us a line giving your dealer's name and address. _ 59 BANK ST., NEW YORK. The Home Workshop A Folding Fireplace Screen (Continued from page 92) If you never have tried brazing, the making of a fire screen presents a good op- portunity to learn, and it is easy. First get a small strip of silver solder and an ounce or two of common borax. The sil- ver is inexpensive, as it is not real silver but an alloy of several metals so blended that their melting point is far below that of brass and yet, when cooled, the joint is so strong that it can be bent without breaking. After it has been melted and cooled, the solder has a yellowish tinge similar to brass. The solder will flow in the flame of a gasoline blowtorch when the metal which is to be joined is heated to bright red at the point of contact. O SOLDER, clamp the two pieces in contact so that they extend over a bench or in a convenient position. Sprinkle on some borax, turn on the flame, and when the brass at the joint has be- come bright red, rub the solder over it until it melts a little. Apply the flame directly until the liquid solder runs bee tween the two pieces of metal; then shut off the gas. In a minute the solder will solidify and make a joint as good as the metal itself. Solder all four frames in this manner, taking care that the corners are carefully squared. When all the frames are made, file off and emery polish the joints and any other places that need cleaning, and prick punch preparatory to drilling. It is necessary to measure only one frame for drilling, as it can be used as a templet for the others. To prepare the brass mesh, cut it care- fully to a size % in. less all around than the outside of the frames, that is 1134 by 2334 in. In order to prevent it from fraying out and to enable it to hold when riveted, a band of solder must be run around all sides. This is easily and quickly done by rubbing soldering paste or painting zinc chloride soldering fluid around the edge and then running a nearly red-hot soldering iron around the edge while holding a stick of solder against the hot iron. Lay the screen on a bench so that it overhangs and rub the hot iron along the upper side until two rows of squares are filled in evenly all the way around. AS THE edge of the mesh will be visible on the inside of the completed fire screen, it should be bound with soft brass or copper ribbon .01 in. thick by 1 in. wide, soldered sufficiently to hold it on one side only and folded over, as indicated. To rivet on the screen, lay it under the drilled frames and mark the proper place for the holes with a gimlet or other sharp tool; then force holes with it through the brass-bound edge. File down the rough edge on the side where the gimlet breaks through. Ordinary auto brake band brass rivets should be used, as these are split, require no washers, and can be headed over quickly. When all the screens have been riveted on, the sections should be joined by rivet- ing on the hinges. (Continued on page 119) r1S) This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See Page 31. nec nex dea sho it e sav re: ar siz lar

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January, 1925

Old Iron Bedstead Converted into an Ornamental Gate HE two ends of an iron bedstead can be used effectively as gates in con- nection with either a wire or an iron fence. An old iron bedstead can be had for next to nothing at almost any junk dealer’s or second-hand store. The ends shown were. bought for 50 cents each. The head end must be cut down so that it equals in height the foot end. A hack- saw will do this, while the castings into

Gates made from iron bedstead ends pur- chased from a junkman for 50 cents each which the bed rails fit can be knocked oft with a hammer. A heavy piece of band iron, from 18 in. to 2 ft. long, as necessary, is bent so that 1 in. extends at right angles at either end. Into each of these short ends a hole is drilled. One of these pieces is bolted to each bed end. Onto the gateposts are bolted or welded short pieces of iron with ends similarly bent and drilled and so -spaced that the two halves of each hinge will fit properly. An iron rod extending from top to bottom holds each pair of the hinges together. To add strength to the gates a sliding shoe of curved iron is provided for each half, fastened by means of a round piece of iron extending into the hollow of each free leg. To lock such a gate a number of devices will suggest themselves besides the one illustrated.—C. L. MELLER.

VARNISHED woodwork that has been neglected can be given much of its old time luster provided it is not stained by the atmosphere. Simply apply furniture wax, rub it in well and polish vigorously. When commercial size is not obtainable readily, plastered walls and ceilings that are to be painted with oil paints may be sized with carpenter’s glue diluted with a large quantity of water.

A Folding Fireplace Screen (Continued from page 118) To give an art brass finish and remove any discolorations caused by soldering flux or heat, scrub the screen all over with a wet brush which has been dipped in powdered pumice. A coat of thin, color- less lacquer will insure the permanency of the bright finish if the screen does not come into actual contact with the fire. If something less plain than a straight top is desired, such as a curved or Gothic top, it will be necessary to cut out the tops from sheet brass with a cold chisel and then file them to the proper shape. A sheet-brass wreath sometimes is added to give a finishing touch. { ! | The Home Workshop| Home Workshop}

POPULAR SCIENCE MONTHLY 119

; sage Er Solves Ever Gift aE Problem f= pu“ AMERIC4,, If He Has a Radio Set Already — It can be made a better one by installing genuine Att-AmeEr- ican Audio Transformers. Two of these instruments, fitted into any set not already equipped with them, will give the receiver greater loud speaker volume with remarkable purity of tone. At-American Transformers are so designed that they amplify fundamentals and harmonics equally, throughout practically the entire audible range. Hence, voice and tones are reproduced faithfully. Give him Att-Americans, the Audio Transformers which, through sheer merit, have become the largest selling transformers in the world. 3 to 1 Ratio, $4.50; 5 to 1 Ratio, $4.75; 10 to 1 Ratio, $4.75. If He Needs a High Grade Receiver— Give him Att-American Super-Fine Parts, and he can build an intermediate-frequency receiver embodying all the most ad- vanced features known in Radio. His set will be the envy of “distance” fans, as well as of his musical friends.

Super-Fine Parts are easily installed. No critical adjustments are necessary. Operation is smooth and flawless. And every part is Att-AMERICAN—ask any Fan what that means in Radio! Sets built with Super-Fine Parts are unsurpassed for selectivity, range, volume, and tone quality. They represent in a very real sense the ultimate in radio broadcast reception. Price, $26.00.

© f ee, : pa” La ALL-AMAX JUNIOR ALL-AMAX SENIOR The ideal gift for the youthful be- The Senior is a complete receiver of ginner in Radio. A one-tube reflex the highest type—a three-tube reflex already mounted on panel and base- with great range and selectivity. It board. Photographicinstructions make comes completely assembled with full wiring the easy task of one evening. * directions for wiring. Price, complete (semi-finished) $22.00 Price, complete (semi-finished) $42.00

‘ rea y RAULANDMEG.CO. The Radio Key Book Pioneers in the Industry “You'll Be Surpri-ed ” Sent LL’ CA ‘ for 10 cents, coin or stamps. A MERI Sf 2668 CoyneSt.,Chicago Largest Selling Transformers in the"World

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31.

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120 POPULAR SCIENCE MONTHLY January, 1993 | Janu The Home Workshop} Old Lace Forms Stencil for Decorative Wall Panels ‘THE latest development in the art of

D whee Ps ap

gS s ( stenciling is to use a piece of old lace ) WA in place of the usual stencils cut from fe pu stencil board. The lace gives exception- TTT ally delicate results when properly used, Es. especially for the wall panels now popular, . f ; > The lace is prepared by giving it a coat ° of shellac to stiffen it. It is fasten of Consider Carefully ed : The parts you select to build your set. Know beforehand that the results will be up to ad ar expectations.. Particular set builders use only Amsco apparatus. They are built and designed by men who really understand radio and are guaranteed to function properly. a Comparison proves their superiority and extraordinary value. SEE THESE AMSCO PRODUCTS AT YOUR DEALER’S pe angers << te LOSS CONDENSER. A laboratory instrument for perfection in set ra uilding. we i 2 AMSCO DUBLWUNDR. Combination rheostat and potentiometer. » MANOA ' vl AMSCO DOUBLE RHEOSTAT. Does the work of 2 old style rheostats. Saves panel heey 4 i space and wiring. \08 Write for interesting literature. Ta Jal , tr |, STENCIL MADE Sp ''S) AMSCO PRODUCTS, Inc., B||||OF LACE: Hy: w Broome & Lafayette Sts., New York : Sa | la

The shellacked lace gives more delicate effects than an ordinary knife-cut stencil firmly against the wall and the color is applied with a stiff stencil brush in the usual way, except that great care must be taken to prevent the design from becom- ing blurred. It is advisable to practise a little before trying the method on a fin-

ished wall. P When dry, the panels are framed with @ panel molding. io Alarm Clock Rings Electric Bells Know that You Can Play ate in Separate Rooms . ability, this famous, free, new US Ne en two separate bedrooms and at the same ~ Holton Talent-Test tells you how : time eliminate the noisy ticking that so ‘ - ti easy it may be for you to win success on annoys light sleepers, I hooked the clock h this easiest-to-learn of all saxophones. gy to an electric call bell system as shown. ar In just a few interesting minutes any unsus- Cal pected gift is brought to view. You determine, @ le

o,8 to your own: satisfaction, how near you really TO OTHER 1At 0 are to new and endless hours of pleasure, social EDICAL authorities agree that 65%, or nearly two- BELL--V ’ eminence, and even increased income if you thirds, of all men past middle age, are afflicted . ( ; 4 a choose. Thousandshavedoneso. Infsirnessto | | sown cause for many of the silments commonly ascribed ALARM KEY | it a yourself, accept this opportunity. | to declining years including, aches in back,* feet and : G } ' in Your request for copy of this booklet brings legs, requent nightly risings, sciatic pains, nervousness * See r] you Appointment, Gard entitling you to the ee ee Sees: Sees St H d alent-Test in the privacyofany | “For a member of the American Association for the | FREE BOOK Holton dealer’s studio, or in | Advancement of Science has discovered a remarkable J t —tells how your own os a yew the — | pote aredicws byerine thet weealty sentores the prostate i test is of our copyrighte phonograp gland to its normal functioning. ready it has been B Fs used by more than 15,000 men—Doctors, Statesmen, ‘, Nr pene <a Teachers _aemageomoe Lawyers, men in every walk of life— \ 6 ° with amazing results. SWITCH- FRANK HOLTON & CO. Elkhorn, Wis. B K c ' America’sGreatestBand Instruments | Roving Y ¥ | R t, 8 Pouny, t \ ; | Mtns eM, =- WALL % : 7] -. a C ‘ | If you will mail the coupon Now ¥ 4 It below you will get, in plain Besid eine bell ite Sieg? he f wrapper, a iree copy of an in- | esides ringing s, this device may i I New Revelation a} j teresting beck, describing this | arranged as a store-window lighting switch t |} new met . t contains tacts | SAXO p H oO N E | ccna man ae know. — j I Y | send immediately, or the | 7 ° % | edition of this ‘book is limited; address | When the alarm goes off, a piece of No. 16 l ss ——2 as aw = eres aw oe ow ews | el ae | ae wee = gage brass soldered to the alarm key re- 1 i | . A ° ; ng ons emma _ Co., a orn, Wis. wl {| THE ELECTRO THERMAL jaa | volves and strikes another strip screwed ] jetermi: talen treet. , Ohio | P it tin tertwaen tae 1) 7 - pa i | to the wooden baseboard. This closes an as : ° Please se a y ation, a copy | ° e e e 1 phone. (Checkif interested in any other instrument): | 4, "cur booklet, “Why Many Men Are Old’ at 40.” | ordinary electric-bell circuit and a hell { 1 Cornet ( ) Trombone ( ) Baritone ( ) Trumpet () | Mai! in plain wrapper. rings in each bedroom. : Name py ame- a aa aa : | One or two switches may be installed ( | Street Address __ QU] Address..........--..-.----------------------- --- | to control the bells. The clock should : ~~ asin I no ns Le eee | be fastened to the base.—W. T. M. | a — 4S Western Office—Dept. 40F, 711 Van Nuys Bldg., Los Angeles, Cal | s

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31.

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January, 1925

Home Workshop Chemistry Simple Formulas that \ Will Save Time ? and Money S

V7 A SOLUTION for re-inking type- writer ribbons consists of the “‘lead”’ of an indelible pencil dissolved in a solu- tion of equal parts of pure grain alcohol and glycerine. Apply to the ribbon with a semi-stiff brush. Ink for labels may be made of equal parts of pyrogallic acid (the photog- rapher’s pyro, not hypo) and green vitriol.(iron sulphate), dissolved in water. The addition of a little gum arabic or tragacanth will prevent any tendency to spread. It is best to varnish the label when marked, using the varnish mentioned last November in this column. A simple ink for writing on blue- prints is made of Y% teaspoon of washing soda (soda carbonate) in 4 tablespoons of water, thickened with gum arabic or gum tragacanth. “Sympathetic”

Splitting es < <e and add- indelible mee Fe ir ee eum pencil }|3& 5 (below) (above) to |i make type- writer - rib- bon ink inks are those that become visible only when they have been treated with light, heat, or some chem- ical. The juice of lemon, orange, or onion, when used as an ink, is invisible, and the characters are developed by heat, applied with a flat- iron. Writings with ferric sulphate are developed by a strong solution of tea or tannin. When paraffin is diluted with benzol and used as an ink, the writing may be read by dusting it with charcoal or smoking it with a candle flame. An etching ink for steel or iron tools consists of about 1% lb. of ordinary rosin, melted, to which is added 1 tablespoon of lard oil—a lubricating oil expressed from lard—and 2 tablespoons of turpen- tine. One or two tablespoons of lamp- black may be added, but this is not abso- lutely necessary. When this mixture or ink is cold, it should be thick. Spread a little on a stamping pad and ink the rub- ber stamp. Press the stamp carefully on the tool to be etched, which must be perfectly clean. Make a border of putty or wax around the design or lettering and pour into this the etching fluid described in this column last August.

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31.

POPULAR SCIENCE MONTHLY 121

The secret of | easy charging — Mayse you think the storage battery a difficult propo- sition. Charging is what used to cause trouble—until we developed The New dilent HO GER Now charging is as simple as ABC. Here’s the HomcuarGer way: Slip two spring clips over the battery terminals, and screw a plug into any lamp socket. That’s all. Go right on using your set, if you want. You can even sleep in the same room with the Hom- CHARGER, it’s so quiet. . So get a good storage battery, the new silent Gotp Seat Homcuarcer, and enjoy radio at its best. Handsome: Finished in mahogany-red and gold. Non-scratching rubber feet. Absolutely safe, absolutely certain, care-free. Unqualifiedly guaranteed. FREE! Ask your dealer or send direct for a copy of the booklet, “The Secret of Distance and Volume in Radio,” containing valuable information as well as com- plete details of the new silent Gotp SEAL HOMCHARGER. THE AUTOMATIC ELECTRICAL DEVICES CQ. Largest manufacturers of Vibrating Rectifiers in the World 131 West Third Street, Cincinnati, Ohio Under the same management as the Kodel Manufacturing Company © 14 GoL_p SEAL HOMCHARGER features (Ee 1—Simple; needs no care. 7—Lasts forever; only one case finished in mahogany- 2—Efficient; costs about 5c moving part, the Tungsten red and gold. to charge the average bat- contact, which can be re- 11—Universal; made in types tery, much less than bulb placed at $1 after many for all voltages of alter- or liquid types of charger. thousands of hours of nating and direct current. Gatch: Wings beltery. up use. Charges all radio “A” and aa _: fl ch alge “4 he 8—Fool-proof; charges auto- “B” batteries, and auto- to full charge Overnight. matically, no matter which mobile batteries. 4—Tapers charge; cannot in- clip is attached to which 12—Quiet; its faint hum can- jure the battery. battery terminal. not be heard in next room. 5—Clean; no bulbs to break, 9—Safe; approved by Fire 13—Unqualifiedly guaranteed. no liquids to spill or pro- Insurance Underwriters. 14—Popular price; sold every- duce fumes. No danger of shock or : where for $18.50, in 6—Dependable; adjusted and fire. Canada $26. Complete, no sealed at factory. 10—Beautiful; sturdy metal extras to buy.

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POPULAR SCIENCE MONTHLY So Many More —Count ’em! When you start to count the product of your machine, you start to get more product. You mean not only to get a count, but to increase the count—and be able to check- up the increase. An initial record of so-many pieces per hour soon leads to so-many more, for the count points the way. It shows what methods, what changes in mechanism show GAJNS— by your COUNTER This small Rotary Ratchet Counter (No. 6) counts reciprocating movements of the lever, as required for recording the output of innumerable small machines. When the lever is moved through an angle of 40 to 60 degrees, the counter regis- ters one. The further the lever is moved, the higher the number registered. A complete revolution of the lever registers ten. This counter can be adapted to no end of counting purposes, by regu- lating the throw of the lever. Price $2.00. (Cut nearly full size.) Small Revolution Counter, also $2.00. The Hand Tally illustrated below is used for counting anything from number of people in a public place, to number of packages in an inventory. In the fac- tory or store it counts stock; in the “open” it may count anything from cattle on a ranch, to poles on a telephone line! Registers one for each pressure of the thumb lever; counts up to 10,000, ‘then repeats. Can be set back to zero from any figure by turning knob once round. Size, exclusive of finger ring, 2 inches greatest diameter. Price, $5.00. Write us about that counting problem of yours—it’s prob- ably solved in the 80-page Veeder booklet; copy free The Veeder Mfg. Co. 44 Sargeant St. Hartford, Conn. dripping of | sins,sinks, and OF Th S rome hipshape | :. COMMON water fau- Leaking eets found in the F aucets home may be one of two types — com- pression or Fuller. The first type makes use of the screw threads for pressure in closing, while the second depends on the leverage of the handle and the attached rods. If a faucet leaks when it is closed tightly, the trouble is with the rubber (or fiber) washer located in the main passage. This washer should be replaced imme- diately, since valve usually is located near the water meter. Every housekeeper should know where it is and how to operate it in case of serious faucet troubles or broken frozen pipes. 2. Open the faucet and let the wate drain out. 3. Loosen the cap (packing nut) witha monkey-wrench or large automobile wrench. To prevent scarring the finish, put a rag around the nut before applying the wrench. 4. Unscrew the valve stem by turning the handle to the left unti a continuous water will add materially to the water bill, a and, what is |g. \ Sez probably p more serious, make stained spots on ba- tubs through the mineral deposits from the water. These stains become _ evi- dent in ashort time and usually are hard to remove. The other type of leak commonly encountered is one that allows the water to spurt out around the valve stem while the water is turned on and sometimes sprays a part of the wall or furniture or wets the operator. It is seldom, however, that a leak around the valve stem cannot be stopped by tightening the cap or packing nut. Washers for both types of faucets ” usually are available at a 10-cent store and always at a hardware shop. The ex- pense is So small that one can well afford to keep one or two washers in store for each kind of faucet, just as extra fuses are provided for the fuse box. To repair a compression faucet: 1. Shut off the water at the valve on the main line leading into the house. This Using rag to prevent wrench marks on faucet ers ae ae 3 5-7 wie Fuller faucet (at left): A, handle screw; B, packing nut; C, cotton packing, which seldom needs renewing; D, rubber ball, which causes a leak when worn; E, ball- retaining nut. Compression faucet (at right): 1, handle; 2, cap or packing nut; 3, packing-nut washer, which rarely gives trouble; 4, main washer, responsible for most faucet leaks; 5, washer-retaining screw 4 IS] This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31. Removing nut on a Fuller faucet with an ordinary pair of pliers it is removed entirely. This is all the disassembling necessary. Now loosen the screw holding the disk washer. If the head of the screw has corroded to such an ex- tent that it breaks, cut out the washer first and tum the screw with a pair of pliers. Fasten a new washer in the recess from — which the old has been removed, trimming it to fit, if neces- sary. A rub- ber, fiber, or leather washer may be used. A hard washer is preferred for hot water and a Soft one for cold. Ex- amine the seat for the washer and make _ sure that it has not become rough where the washer was worn away. If it has, it should be smoothed. This often can be done with a screwdriver or the square end of a narrow flat file. Some faucets have seats that can be replaced with new ones. Put the valve back in place and tighten the packing nut. If the faucet turns too hard, the packing nut has been made too tight. To repair a leaky Fuller faucet: 1. Shut off the water at the main valve and drain the faucet. 2. Disconnect the faucet at the middle joint. This is necessary because the washer is not located on the valve stem and is not accessible from the top of the faucet. If there is no middle joint, the faucet is of the compression type; this is the most obvious distinction between the two kinds. 3. Replace the rubber ball or washer by removing the small nut. Put in new rub- ber and replace the nut. Reassemble the faucet after having examined it for other possible troubles.—E. E. ERICSON. trou strai plish agai tos boai corr surf will [ sma hav at 1

Page 91

Water know ase of nN or Water vith a nobile finish, plying irning until screw an. ex- ut out turn W With r of Fasten washer Tecess which d has noved, 1g it to neces- A rub- er, OF washer » used. washer ferred water oft one . Ex > the sure where has, it can be re end s have y ones. ‘ighten ‘ns too de too 1 valve middle se the e stem of the nt, the this is en the sher by w rub- ble the r other ‘piping makes it : IN REPLACING a Puttying — broken pane of glass, Windows the home worker — usually has little trouble except in making the putty look straight and neat. This can be accom- plished by pushing a piece of cardboard against the edge of the putty, as shown, MON) Wid “uM to straighten it. One corner of the card- board is mitered and used to true up the corners of the putty. If linseed oil is brushed on wood surfaces that are to be puttied, the putty will not readily dry up and fall off.— WARREN SCHOLL, Saint Ignace, Mich. Repairi WHEN a door-knob epairing was pulled off re- Door-Knobs cently in my home, I found that the small setscrew had broken in two. Not having a screw of the right size available at the time, I drilled right through the shank of the knob, re- placed the knob on the spindle and passed a cotter-pin through the holes, as shown. The ' ends of the pin were | bent round on the out- side. The repair was | » ineonspicuous and COTTER-PIN there was no danger of (Pinholdsknob the knob’s coming off again.—D. R. V. H. ; To SHORTEN the Water Supply | aaity job of filling for F urnace the water pan of my . hot-air furnace, I have installed a supply pipe, as illus- ‘| trated. This was done by removing the 34-in, plug in the side of the hot-water tank, which stands near the furnace, and substituting a 34 by \ in. bushing. A short 14-in. nip- ple was screwed into the bushing, followed by a globe valve and 2 lengths of 44-in. pipe con- nected by an ell. The end of the pipe was brought down to about 3 in. above the pan. This additional possible to fill the t : Connections for water pan in a few filling vapor pan seconds.—G. M. ee © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS, POPULAR SCIENCE MONTHLY Five Tube Se Aas Only OneDial to ‘June Just ONE Dial to turn to get coast to coast range. Just ONE Dial to adjust to get perfect tone reception. Just ONE Dial to tune to get the utmost in selectivity. tRE—at last—is a five tube tuned radio frequency Receiver with a distinctive simplicity of design. It is a beautiful set, and with its simple ONE Dial Control it will do anything any other five tube set will do,—and will do it with one setting of the dial! Tunes Out Local Stations—Gets Distance Easy Just ONE Dial to turn on the MOHAWK, and as you turn it you tune in station after station covering the complete range of radiocasting wave lengths. It cuts out the nearby stations with ease and brings in the distant ones clear and distinct. You can operate it with an aerial of any length to give satisfactory results under varying conditions. ° The “~ 5-Tube Receiver Built in a distinctive period type walnut cabinet, it will instantly appeal to the artistic taste of the most critical. Yet its beauty is not “only skin deep.”” The quality goes clear through. Don’t fail to see the MOHAWK—hear it, and try it, before you buy. You might pay more—but you probably wont if you try the Mohawk first. Ask your dealer about the new MOHAWK. If he does not have it, accept no substitute. Write us. Handsome de- F it E E. scriptive folder tells all. Prices, specifications and remarkable results. FREE on request. MOHAWK | ELECTRIC =F CORPORATION | * 2236 Diversey Blvd. _ CHICAGO, ILL. Dealers and Distributors Wanted Everywhere See page 31.

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POPULAR SCIENCE MONTHLY The FAN STEEL. The Balkite Battery Charger is entirely noiseless. It can be used while the radio set is in use. It has no moving parts, vi- brators or bulbs, and has noth- ing to break, adjust or get out of order. It is simple and unfailing in Balkite does not create disturbances in your set or your neighbor’s PRICE $19.50 ‘s) $20 West of Rockies, $27.50 in Canada Tested and Listed as Standard by Underwriters’ Laboratories U.S. Patent 1,495,582 Batte Changer operation. It cannot discharge, short-circuit or damage the bat- tery by overcharging. Besides charging “A” batteries it will also charge “B” batteries of the lead type in multiples of 6 cells. Sold by all leading radio dealers. Manufactured by FANSTEEL PRODUCTS CO., Inc., North Chicago, Iil. Don’t Blame Your Set! If the batteries run down, you’re lucky to get anything but “sounds.” APCO Battery Charger keeps radio batteries alive. Works noiselessly, efficiently, surely, fully charging any radio battery over-night for a few cents. 7% ampere capacity. Pays for itself in six months. Guaranteed one year. Write for circular and dealer’s name APCO MFG. CO. Baker Street, Providence, R. I. APCO BARS ,, for “A” and “B’’ Batteries How to Become a Successful Electrician By Prof. T. O’Conor Sloane. The studies to be followed, methods of work, field of operation and the requirements of the successful electrician are pointed out and fully ex- plained. 202 pages. Price, $1.50. POPULAR SCIENCE MONTHLY 250 Fourth Avenue NEW YORK Tool Cases for Machinists, Car- penters and Tool Makers; none better; thirty styles. Quarter- ed oak and metal cov- ered. Ask for booklet. ve **Built for Service’”’ ~The Pilliod Lumber Co., Swanton, Ohio BARGAIN CATALOG Yours Get it now! Crammed fullofinforma- tion and offers of all kinds of complete RADIO SETS, Accessories Parts and Only $21.95 for 1-tube ol it, receiver parts unas- sembled; often receives over 1,000 miles, Only $53.78 for 2-tube outfit, receiver as- Ver y sembled: often’ receives over ° * miles on loud spe inter esting ! 1,000 aker, ow d $85.09 for 5-tube Neu- trodyne outfit, receiver parts unassembled; has received Eng- land. These prices include all accessories, aerial, etc.--every- thing needed for receiving on head phones. Also, Crosley receivers, 10°/, off. 25 other popular sets away down. It’s easy to do business with us, for this is ““The lio House of Friendly Service.’’ All goods offered subject to examination and approval. No money in advance. ick shipment. We pay transportation anywhere in U.S. tisfaction or money back. Your questions answered free. Get this wonderful catalog — you need it — write today! (And will you be so kind as to addthe names of several friends you believe will soon want_radio goods ?_Thank you !) MAIL ORDER HOUSE LIBERTY Dept. A-164, 106 Liberty St, N.Y.C. IS] This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. January, 19, = ‘ s peel The Home Worksho)| Mason Jar Is Cheap Protecto,| for Exposed Electric Light ‘THE simplest and cheapest way to ite tect an electric light placed jp exposed situation or where it might be broken is to cover it with a Mason jar, » shown below. : A hole is bored with an expansive pit in a square block of wood large enough t, take the cap of the jar. This is Pressed in How the jar is fastened over the electric lamp tightly and held with a few small naik, Inside the cap is placed a thin block, to which the keyless porcelain socket is fas tened. Holes are drilled through the thre parts to take the electric wires, and the whole is fastened in place with nails o screws. The wires are connected, the bulb inserted, and the Mason jar screwed in place as a cover. A MATCH, that has been scraped, partly split, pointed, and moistened, makes a good pair of tweezers for removing par ticles, and expecially turned eyelashes, from the eye. Dressing Up Your Radio Receiver (Continued from page 90) and wherever a wire joined another wire, we used solder tees. Although it required searching around to buy them, we ob- tained nickel-plated soldering lugs and tees to match the bus bar. Instead of using a piece of packing case for a baseboard, we used a highly finished piece of clear wood. Instead of brass brackets, we made brackets from an old aluminum coffee-pot and polished them to look like nickel plate. After the set was wired, we tested it, “shot all the trouble,” and then put it in our cabinet. We drilled the rear of the cabinet and_set in “‘key socket bushings” to lead our battery and aerial wires through, and screwed on the panel with nickel-plated oval-headed countersunk screws (14 in., No. 5), and didn’t let the screwdriver slip once! Dad’s set is now three months old. We are up in the attic every night with the “‘superhet,” listening to the distant sta- tions, but we have a little secret. One night after a dance we tried out Dad’s set for distance, and would you believe it— we had a station that our ‘“‘superhet” gets about once a year. So good workmanship counts in efficiency as well as in looks. See page 31. need macl the mac! illus' clam of 1/ 1 in with bolt righ’ silhc eye, Al

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tector ight y to Pro. d in an ight be D jar, a ive bit Lough ty ressed jn Il. nails, lock, to t is fas. e three and the nails or ed, the screwed _ Partly rakes a ng par- elashes, ceiver or wire, equired we ob- gs and ng case finished f brass an old them to sted it, ut it in of ‘the shings” | wires el with ersunk let the ld. We ith the nt sta- . One 2d’s set ve it— t’? gets ,anship ks. -———$—= January, 1925 ——__ ee ar nr ae The Home Workshop lashlight on Sewing -Machine : "Aids in Threading Needle FTER wearing out my patience in threading the needle of my sewing- machine, I attached a flashlight to the arm of the machine head, as illustrated. The clamp is a strap of 1/16-in. brass, 1 in. wide, held with a pair of bolts and wingnuts. The light is in the right position to throw the needle into | silhouette, thus illuminating its elusive | eye, so that threading it becomes easy.— | PHILIPPE A. JuDD, Portsmouth, Ohio. Auto Tire Improves Sawbuck GECTIONS of an old tire casing fitted over the horns of a sawbuck are a surprising aid in holding sticks of cord- wood in place. The rubber should be nailed on as shown above, so that the slight bulge of the tread is facing in- ward.—C. L. MELLER, Fargo, N. D. Radiator Furnishes Heat and Increases Hot-Water Supply O PROVIDE additional heat in the bathroom and at the same time in- crease the amount of hot water available for washing purposes, an ingenious exten- sion of the water-heating system recently was made in a small house in Washington, D.C. HOT-WATER SUPPLY A hot-water ra- diator was placed in the bathroom and connected as indicated with the IN furnace coils so that it serves as an auxiliary hot-wa- ter tank. The coils in the furnace were increased in size correspond- ingly and a valve was provided for cutting off the heat when not required. Care was taken not to place the valve where it would cut off the supply from the water main to the EXTRA COILS! FURNACE Connections for the auxiliary radiator heating coils and regular tank.—G. A. L. POPULAR SCIENCE MONTHLY é GREATER Veutrodyne EAGLE New Model B 5 Tubes cPRalanced -—Receiverr Good Reasons For Buying The New Model B Eagle Receiver GUARANTEE The warrantee that accompanies every Eagle Receiver fully pro- tects you. Exclusive Eagle Instruments Multiple (filament control) switch, ball-bearing, die-cast condensers, re- volving resistor element rheostat— refinements of the neutrodyne re- ceiver found only in the New Model BEagle. Cannot be purchased ex- cept as incorporated in the Eagle. BALANCE the perfect balance of tube capaci- ties, which is the secret of neutro- dyne efficiency. Assured by expert workmanship and repeated check- ing tests before each set leaves the factory. MODEL BS f A New Eagle Artistic Console Cabinet Price $100 An artistic Console cabinet for the EAGLE in American Walnut or Mahogany, with tume-proof com- partments for battery and charger. EAGLE 26 Boyden Place IS] This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31. Yeccace, “When Mt, ear By: 7 Crt de *s ser 4 Letra) AVOre , meet —coulh “have fount guet une d J Te) ee ee the i ls he eked he thea a yea “Was Ja cta Chawea ook we y ~/ teth tke 2U/ SY Ses Ler tone 1 sons Kettle eo me thaw toon Gaata ia oy eR es eer gs 9 Z ce ht prec to complheated ae ue Se the ae piety Le ‘4h ha operate as rn. ¢r ja hi Le es ye +t a a J Ah wv aie 16 g* all ae iD 4d deecde or the fertogptam / wt e te e hae tat turd the dite te tthe nantes for thet ttatinv. (We mere by pore» neey Leon Cvtri n4yz, ull timea My % hey Hecps me tn tirctac nid, Bhs, 10, ote the ect tater def anonty owl buy, to which Lruplicd, , 6 Coutdse, Acdw te! SE0et-schkeet it wane. a. Ho - tas new Meodil ur 3 oh cs poe BE bk Liaiget “s puret the set _hes woh ; eecate thio wonderful gift uw sh ined EOE poms es ~ tf Morrchert tn Licensed by \oe 3 Fen dene Radio Manviactver y é F | jTR DY r & 3 i RO 2 mn 27. and é Te oe 430,000 2 ey 4nd; — L¢ Other Patents Pending ny Write for Literature sosn SN ) fcr = nt LE R, mv wenn Bee sg . ~ RADIO CO. NEWARK, N. J.

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POPULAR SCIENCE MONTHLY

HIGH SCHOOL COURSE IN| TWO YEARS YOU ARE BADLY if you lack HANDICAPPED fist School You cannot attain business or social prominence, You are barred from a successful business career, from the leading professions, from well- paid civil service jobs, from teaching and college entrance. In fact, em- ployers of.practically all worth-while positions demand High School train-

ing. You can’t hope to succeed in the face of this handicap. But you can remove it. Let the American School help you. BIG FUTURE This course, which has been prepared by some of America’s leading professors, will broaden your mind, and make you keen, alert and capable. It is com- plete, simplified and up-to-date. It covers all subjects given in a resident school and meets all requirements of a High School training. From the first lesson to the last you are care- fully examined and coached, USE SPARE TIMEONLY Most people sdle away fifty hours a week, Probably you do. Use only one-fifth of your wasted hours for study and you can remove your present handicap within two years. You will enjoy the lessons and the knowledge you will gain will well repay the time spent in study. Check and mail the coupon NOW for full particulars and Free Bulletin. American School Desf. H-175 Drexel Ave. and 58th $f., Chicago 290 eh ET A HRN ON ORT CCN LN ON AT A American School Dept. H-175 Drexel Ave. & 58th St., Chicago Send me full information on the subject checked and how you will help me win success. FIT YOURSELF FoR Af | Law

Accountant and Auditor Designer Power

annnnanene

The Home Workshop Turning Off a Water-Heater from a Distance By W. W. Michaux Y PRESSING a button in the bath- room I can turn off the gas water- heater in my kitchen. The remote con- trol system by which this is accomplished was installed for $2. . It saves many steps and much gas, and would be even | more useful in a house where the water-

To a board under the water-heater I | attached an ordinary door-bell with the | | | heater is located in the cellar. | | | | | gong removed. This I connected with a | pushbutton in the bathroom and with another in «% kitchen, as well as with the _ trans- former that supplies the current for the regular door-bell system. Dry cells, of course, could be used in place of the trans-

The control i in the “on” position (at left). Ringing the bellcauses the clapper to strike a spring

which is ep rine former and would give equally good results. I bent one end of a 6-in. length of flat iron at right angles, beveled it off, and filed a small notch init. A coilspring was fastened to the other end and the piece was fastened to the gas cut-off lever, as shown above. The coilspring holds the lever in the cut-off position until it is turned on by hand, when the notch in the beveled end of the iron strip is hooked in a small flat sufficient water has been heated, the button in either the bathroom or the kitchen is pressed. This causes the clapper of the bell to vibrate and hit the flat spring, jarring it sufficiently to release the notch in the flat iron strip. Thereupon the spring pulls the lever to the off posi- tion, shutting off the gas.

Broken Type Cleans Bottles O CLEAN dirty bottles when other methods fail, obtain from a print shop a small quantity of old type. Break it up into small pieces, place them in the bottle to be cleaned with some hot water, or strong lye, and shake well. The sharp edges of the type will loosen hard and stubborn deposits more quickly than lead shot and may be used over and over

again.—H. L. W. convenient position in the | vibrating | catch and free | the lever, |

| | electric | | j | | | | | | | closed by the | (above) | spring attached to the bell board. When |

ree et MAKE and keep your cellar dry by filling cracks and coating concrete or brick walls and floor with Smooth-On No. 7. Excellent also for waterproofing garage, stable and wash-room floors, boiler pits, cisterns, septic tanks, water troughs, foun. tains, duck ponds, swimming Pools, manure pits, etc. Requires about 25 Ibs. of Smooth-Opn No. 7 for each 100 sq. ft. of surface and you can do the work yourself. Smooth-On No. 7 is the only practical waterproofing material that can be effectively applied from inside and to wet or dry surface. Can also be laid in a thicker layer over worn wooden floor for concrete effect and watertight surface that is easily washed and kept free from odors, Sold in 5 and 10-lb. cans and 25, 50 and 100-lb. kegs. Write for Prices and FREE BOOKLET , SMOOTH -ONn — * batteries. Can 4 a kooe of Ser ome case—and ~ ae ee et acid ge of thi this remarkable introductory hands = chal fot fini ah ant be,prefer ‘tan lasted aur the? aie , ome n: e 1 0 2 tery. Be sure to specif. hich ia wan GIVEN FREE

1S) This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31. zo introduce Fn woe eB. St tor Pattery to Public ——__—«s§ =

ek eee pe:

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. J, January, 1925 POPULAR SCIENCE MONTHLY ea . The Home Workshop Sturdy Pedestals and Smoking Stand Built on Craft Lines By J. T. Garver HE characteristic sturdiness of these Dutch craft pedestals and smoking stand will appeal to the man or boy who likes to build furniture. While ‘oak or walnut are always prefer- able, the inexpensive and easily obtained soft woods, such as pine, poplar or gum, if well seasoned, will answer well in the construction of these pieces. The heavy center pedestal in the photograph below is made entirely of chestnut. The parts needed for pedestal A are: 4 uprights, 34 in. thick, 4 in. wide and Two types of pedestals, one heavier than the other, and a smoking stand (at right), and dimensioned details show- ing the sim- plicity of con- struction (be- low) \ TOP RECESSED FOR ASHTRAY £5) ats) ha GLASS ASHTRAY ‘| 2 ft. 74 in. long; 1 standard, 11% in. square and 2 ft. 614 in. long; 1 eight-sided top piece, laid out in a 11%-in. circle, 34 in. thick; dowels, finishing nails, glue and screws. When one upright has been laid out as shown, it may ke used as a templet for the others, as well as the uprights of the other two stands shown. After the top has been cut out, find the center on the under side by drawing cross lines and mark the position of the stan- dard. After placing the dowels in the standard, mark and bore corresponding koles in the top, being careful not to go clear through. With the standard and top in position, bore four slanting holes in the top of the standard, countersink and after applying glue, make a rigid joint by tightening the 114-in. screws. (Continued on page 128) Desens ISARGENT SARGENT Planes have been used for years on construc- tion work from one end of the country to the other. They are fashioned from finest metals, perfectly finished and easily adjusted. They are designed to make short work of the hardest jobs, to stand up under the strain of constant usage. Yet they are so moderate in cost that they should be on every home or school work-bench. PLANES You need the two types The larger is the Sargent Auto-Set Bench The auto-set feature permits the chromium steel cutter to be removed for whetting and replaced with- out changing original adjust- The Sargent Steel Block Plane is great for smaller jobs and cross-grain or knotty surfaces. See both at your hardware dealer’s and write for booklet. SARGENT & COMPANY, ris) 50 Water Street, New Haven, Conn. shown above. Plane. ment. oe N Bench Plane 2 Built for master carpenters .- best for home workshops Manufacturers Sargent Steel Block Plane Sargent Auto-Set _ 10 MINUTES! Banjo sO” G Amazi fae Lean oS ence Banjo or iter. in. 5 io knowledge ~ ne cousary ce pena aes tones yoky ee henly wattached "to to veka ro played “ah Ushers number" Keys. id way. Send for PREE = = Free Book : raat & ing oF N. Halsted St., Dept. 9781, Chicago, Ill. pUass 25¢PIN ae om DIRECT FROM THE MAKER” : , CATALOG FREE & Either pin shown made with any 3 letters and 2 figures. 1 or 2 colors enamel, Silver plate 25/ ea. $2.50 doz. Sterling silver. 40¢ ea.. $4.00 doz. Y BASTIAN BROS. CO. 591 Bastian Bidg., Rochester, N. Y. PLAY A TUNE IN by — cup, ) conte. Send = it today. G. ical s “Engineer, Box B47, Los Angeles,Calif, Paka information about contest in ~~ which you may win a silver Flies Without Motor The GETTINS OCTOPLANE Altitude precord 2020 Ft. Glide Record 5146 Ft. Be tan detailed instruc- tions and license under Pat. 1439232 enabling anyone to build one of these wonder- ful gliders 5 feet long, and sent postpaid for ttins, Aero-Mechani Bevteis-sie 21 Jewels Nothing less than 21 Ruby and Sapphi Le is good enouch for Burlington masterpi Dh am epee } Company ff 9th Street and Marshall Bivd. Chicago, IMinois fe © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31

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POPULAR SCIENCE MONTHLY © Its “voice’”’ is not a phone unit. So Natural You Want to Look Inside for the Performers! You'll be genuinely surprised at the full, round, musical tone of this new Cabinet Audiophone. It is an adjustable electromagnetic device that gives pleasing quality to the most powerful tones, yet is as sensitive as any loud speaker ever built. For distance “fishing,” or for volume on con- certs, it gives you radio at its best. Genuine mahogany. Size 17 x 10 x 1014, just right for top of radio set or phonograph. Price, $30.00 at your dealer’s. Other Audiophones at $25.00, $20.00, $15.00 and $12.50. The Bristol Company, Waterbury, Conn. LOUDSPEAKER TRADE MARK Bristol AUDIOPHONE EG. U. S. PAT. OFFICE 8 — Circular r usefulness! Canadian Factory: biped weave hctisss ff Il fele] | | Vit DWORKING ip saw At last! a 100/ Woodworker © Only $225.0 r compete with motor inch Circular cross cut saw 11 inch Band saw 4inch Jointer, Shaper 10 inch sander Lathe -14 inch swing tre ARKS Cabinet Shop Special is as complete a small shop equipment as you can buy! Everything in one com- pact unit with motor! Just the machine for your home shop —for the cabinet maker—novelty and toy-maker—special furniture builder— for the farmer who makes crates, bee-hives, etc. his own No end to its Complete, or without motor and at- tachments to suit your needs. Write for circular The Parks Ball Bearing Machine Company 1547 Knowlton St., Cincinnati, O. 200 Notre Dame East, Montreal, Can. peptpigurtorecial i | KS FREE | Greatest Catalog | f of Radio |! ee Bargains | upplies, com- te parts for sets, complete sets, etc., mine of very latest information on all circuits, complete list of broadcasting stations and other valuable data. Send your name and address and we'll cend FREE CATALOG. | Our RANDOLPH RADIO co BUILD YOUR OWN RADIO SET All complete parts for the following sets consist of standard advertised guaranteed parts and include drilled bakelite panels and wiring diagrams for easy set construction. , - $ 8.95 Ultra Audion Circuit . .. Five Tube Licensed Neutrodyne 33 One Tube Cockaday .... Three Tube Cockaday . . . Eight Tube Superheterodyne One Tube Reflex. . ... Two Tube Reflex. . . « « Three Tube Reflex . ... Four Tube Acme Reflex .. Five Tube Improved Cockada' One Tube Reinhartz .. Three Tube Reinhartz. . Two Stage Amplifier . Order from this ad and send oe e See eevee FREE SERVICE DEPARTMENT radio engineers will help ou solve all your radio prob- lems, and furnish up-to-date information on set construc- tion, operation and improve- ment. This service is free to our customers. HEADPHONES “Randolph Special” 2200 Ohm moulded headset 59. N. UNION AV, @CUDEICM CHICA © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31. pThe Home Workshop Wire Brushes Made Quickly from Rolled-Up Netting \ X 7 IRE brushes are exceedingly usefy tools in every home, workshop ang garage. They are fitted for freeing ep. gines from dust, dirt and carbon, remoy- ing paint and varnish, scraping insulation from wire, scouring pots and pans in the kitchen, taking off caked mud from ryp. ning gears of autos, cleaning files, anq many other purposes. These brushes may be made easily at very little expense. The brush proper jg wire cloth cut into strips and rolled or folded to the shape desired. The ends of the wires form the “‘ bristle’’ part. Several useful brushes are illustrated, An old wooden drawer pull serves as the handle for the short round brush. The brush part is a long strip of wire cloth about 1144 in. wide. Handle and knob are FOR NARROW SPACES ROLLS OF WIRE NETTING Four types of homemade wire brushes. Many others may be prepared as needed connected together by a strip of metal, which is soldered to the brush and held with small screws or brads to the handle. The method of making the other brushes is obvious. The wire cloth should be ofa mesh to suit the work in hand.—S. W. B. t Sturdy Pedestals and Stand (Continued from page 127) After applying glue to the inside edges, fasten the four uprights to the.standard with long finishing nails. Toenail at the bottom. Set the nails and fill the holes with glue, stain and wood file dust. thickness of the uprights, which are 1% in., and the faces of the inside standard, which are 21% in. The top is 1% in. thick and is laid out on a 12-in. circle. The smoking stand, C, is constructed about a center standard 1 in. wide on its three sides. The top may be round or hexagonal, 6 to 8 in. in diameter, and 34 to 1 in. thick. The wood should be well sanded and all edges chamfered before finishing. A bog | or wax well rubbed. or weathered-oak dye is recommended, followed by a light filler and a flat varnish Pedestal B is similar to A, except the

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1es. led netal, | held indle, ushes e of a W. B. ad ges, idard it. the holes t the 21% dard, Z, in. ‘le. ucted le on ound and 1d all \ bog nded, rnish January, 1925 aS) Unique Safety Lock Opened by a Key Made of Bent Wire OR the door of a boy’s room, the F safety lock illustrated may be made cheaply and easily. It cannot be picked by any one who is not in the secret and it will hold the door against anything but e violence. This is also a good lock for a chest, cupboard, toolhouse, or chicken-house. The lock itself is nothing more than a polt that is shot home by a special wire key. The bolt, which must slide easily in two guides, may be made of wood, although it is far better to use strap iron. The thickness of whatever material is used depends upon the strength desired. For a small lock the strap may be 4 in. long. One of the guides is at the edge of the door; the other is about 3 in. away. The bolt is drilled with 6 equally spaced holes, as shown. When it is shot, it en- The bolt, its guides, and the stops that pre- vent it from slip- ping too far to the right or left The special key (above) and how it is used to throw the bolt (at left) gages a U-shaped opening, also made of iron, or an iron plate and two wooden spacers. The keyhole is placed any distance below or above the bolt; 2 or 3 in. usually is sufficient. The key is a very heavy piece of wire. Beginning at one end, bend Yin. at right angles. Measure from this bend a distance corresponding to that from the bottom of the keyhole to the center hole of the bolt. Make a right- angle bend at this point. Leave 1 or 2 in. and bend again to form a conventional key handle. To open or close the lock, insert the key, turn the end upward toward the bolt, pull the wire toward you, and feel for one of the holes in the bolt. When the end en- gages a hole, turn the wire like an ordinary key and the lock will open or close, as the case may be. No other piece of wire except the special key will open the lock, and no one will suspect the method if the work is done carefully.—E. B. For radio material, see ‘‘Dress- ing Up Your Radio Receiver,’’ page 90, and the regular Radio Department beginning on page 76. “BUILDING AN AERIAL MAST”’ will appear next month. | POPULAR SCIENCE MONTHLY ui | | Engineers develop 129 d this special | panel material for radio ONLY HERE is nothing quite like Radion —‘‘the supreme insulation’ —for real results. Authoritative labo- ratory tests conclusively prove highest insulating characteristics. In the set you build, it may give you just that extra energy needed to tune in a dis- tant station. When you see Radion in a ready-built set, it is usually an evi- dence of general good quality in that set. The beautiful, high-polished finish of Radion keeps out dirt and moisture, which even in little particles on the surface, sometimes cause short circuits and reduce good reception. Radion is the easier panel material to drill, cut and saw. There are eighteen stock sizes, two kinds, Black and Ma- hoganite. Sold universally by dealers who know radio. Better performance will make it worth your while to ask for it by name, and to look for the name on the envelope and the stamp on the panel. Send for Booklet Radion dials to match, also sockets, binding post panels, insulators, knobs, and new Radion Built-in Horn. Our new booklet, “‘Building Your Own Set,”’ giving wiring diagrams, front and rear views, lists of parts and directions for building the most popular circuits— mailed for 10 cents. Send for it today, AMERICAN HARD RUBBER COMPANY 11 Mercer St., New York City Chicago Office: Conway Building Pacific Coast Agent: Goodyear Rubber Co., San Francisco—Portland RADION The Supreme Insulation © PANELS Dials, Sockets, Binding Post Panels, Etc. AMERICAN HARD RUBBER CoO., 11 Mercer St., PS-1 | New York City ] Please send me your new booklet i “Building Your Own Set” for which I enclose 10 cents (stamps or coin). ! Z > 3 TESTS SHOW FORD CAN RUN 60 MILES ON GALLON OF GAS The amazing fact that a Ford can run 60 miles on 1 gallon of gasoline: was recently brought to light through tests conducted by America’s foremost engineers. Great strides have already been made in this direction by the recent invention of a simple attachment which can be installed in a few minutes without any alterations to motor. A. C. Winterburn made 41.4 miles on one gallcn of gasoline after this device was attached. B. O. Weeks, famous aviator and inventor, wants agents and wil: send sample for trial. Write him today at 1304-736 Fondulac Ave., Milwaukee, Wis. rIS} New in principle, new in shape, new in quality of reproduc- tion, price $27.50. Made by the makers of the famous N & K Head I IE Set, Model D, 4000 ohms, UDSPEAKER irice $8.50. TYPE W TH. GOLDSCHMIDT CORP. Dept. C-1, 15 William St., N.Y, © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31. @ Adds as rapidly and accurately as ayy # $300 machine, yet fits the vest pocket. & Mechanically perfect. Easy tooperate —nothing to get out of order. Everyone ™ who uses figures should own one. Counts Up to 999,999,999 Total visible at all times. A pull of the finger clears it. Don’t carry a pocket full of pencil stubs and sera ; paper to do your figuring. Carry a Ve-Po-Ad. . Send no money. 10 Days Trial Just name and ad- * i} dress and we will send machine postpaid. i Pay postman on delivery $2.95. Use it for mi, 10 days to prove it does all we claim. If fm, not perfectly satisfied we willrefund your 4 & money. Limited supply. Send order today. Reliable Adding Mach.Corp.,Dpt. 46 170 W. Washington St., Chicago, Ill. Here’s a money maker. Everybody A = E N T ~ wants one. Splendid profit, rite for special offer.

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WurilIzeR Couldn’t Play a Note— Now Makes $100 a week “Bill Carola’ Landaus Serenaders Read Bill Carola’s story in his own words— **When I sent for your catalog, I wanted a Tenor Banjo, but I hesitated a longtime as I didn’t know a note of music. I finally decided to try it a week, as you offered, and at the end of that time I found I could pick a few notes. Then I started the correspondence course you furnished, and in seven months, even before the final payments on the Banjo were due, I I had taken my place in a professional orchestra. Now I am making $100 a week, three times what I made as aclerk, Two of my friends made money with their instru- ments after five: months practice, one a drummer and the oer e a 5 aphenist, ond metther could play a note when he ih everybody knew how easy it is—anyone who om on wile a tune can learn to play a musical instrument.” Bill Carola New Offer Learning to Play ade Easy We now furnish with every in- strumenta Free Scholarship Certificaie. This scholarship W atitios you to free tuition in one of the foremost correspondence schools of music inthe yoer 6 Whether you want to learn to play for profit or only for pleasure, this Free Scholar- ship will make it surprisingly easy for you, Free Trial Easy Payments You may have any Wurlitzer in- strument for a week’s free trial in — own home. No obligation ae ed are arranged in a a mon sums,a Sowaneie: a day will at or your instrument. Wurlitzer instruments are the re- sult of 200 year’s experience in musical instrument building. Famous for artistic quality, rich tone value and fine workmanship. Used jin the finest bands and orchestras throughout the world. Free Book Illustrates and describes every known musical instrument—over articles. Special offers on complete outfits. Special prices direct toyou. We also give you our Free Tri Easy Payment = plan and special Free Scholar- iD ship Offer. No obligation. ( ji ta) Send Coupon Tod Li Sox Dept. 1781 ee a 30, Gleb in, Claw 120 W. 42nd St. New York 259 Stecton St, San Francisco Send me your Free Book on Musical Instruments. Also 'your Free Trial, Easy Payment plan and Free Scholarship offer. No obligation. Name Instrument (State instrument in ‘which you are interested) , Copyright, 1924, The Rudolph Wurlitzer Co. POPULAR SCIENCE MONTHLY Better Shop Methods. A Small Boring Tool I Have Found Useful ERY often a mechanic has to have the toolsmith forge a tool for boring small holes or threading a special job. The delay and cost of having this done may be avoided if a holder like that illus- trated is at hand. The body and head are made from scrap steel. It is not necessary to machine the sides of the two pieces; just clean them off against the side of an emery BORING TOOL x, * SS ESSN BW FLAT Yep This simple holder is for use with small boring and threading tools made of drill rod wheel. The 45-degree V then is milled or cut with a forming tool in the shaper. Mill the piece for the head to the cor- rect width and depth and clamp it to the body, drilling through the two parts for the rivets. A hole is drilled and tapped in the top of the head for the setscrew. The rivets then are headed and the holder is ready for use. Boring bars and threading tools may' be made of drill rod from 4 to 3 in. in diameter for use in a holder of this size.— Harry E. RIceg, Rutland, Vt. Prizes Offered for Photos of Labor-Saving Tools T COMES in very handy many times in my work about the tool- room,’ writes Harry E. Rice, a reader of PopuLar SciENcCE MonrTHu y, in re- gard to the toolholder described above. If you are a machinist, probably you have used a similar idea. At any rate, you have made useful or unusual tools or fixtures for accom- plishing work that could not be done easily with your regular tools, or with tools you could go out and buy. Send clear photographs of any such tools, with a brief description of their construction and purpose, to the Editor, Better Shop Methods Department, PoputarR ScIENCE Montuty, 250 Fourth Avenue, New York. For each photograph avail- able for publication, PoPpULAR SCIENCE Monrtnty will pay four dollars. | i “ \y A. CUNNINGHAM AMPLIFIER TUBE TYPE C 301A PATENTED RADIO — Sensitive — Selective —Ruggedly Enduring Price the same on all five types— C-301A, C-299, C-300, C-11, C-12. Patent Notice: Cunningham tubes are covered by patents dated 2-18-08, 2-18-12, 12-30-13, 10-23-17, 10- 23-17, and others issued and pending. Licensed only for amateur experimental and entertainment use in radio communication. Any other use will be an infringement, Cunningham 40-page Data Book fully explaini and ag nego of Radio Tubes now available ing care ing 10c in Za to San Francisco Office. jon CHICAGO NEW YORK “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 I had them in, myself, only that I hear all right.” The Merley Phone for the DEAF is to the ears what glasses are to the eyes. Invisible, comfortable, weight- less and harmiess. Anyone can adjust it. Over one hundred thow sand sold. Write for booklet and teatianctit als. THE MORLEY CO., Dept. 797, 10S. 18th Street, Philadelphia DON’T WEAR, A TRUSS BE COMFORTABLE— Wear the Brooks Appliance, the modern scientific invention which fi es rupture sufferers immediate ne ef. It has no obnoxious sp prings of in “5 UBES HOME OFFICE 182 Second Street SAN FRANCISCO pads, Automatic Air Cushions gad ow to: weaved the as ag o salves or plasters. Durable a0. iM Sent on trial to prove its worth. MR. C. E. BROOKS ware of imitations. o % for trade-mark bearing portrait and signature of C. Brooks which appears on — a. None ya genuine. Full information let sent free in plain, sealed envelope. BROOKS APPLIANCE CO., 230-A State St., Marshall, Mici» FREE YourName Me VALU E THEPER PERFECT WRITING INSTRUMENT TheNew Im ed Writes like pencil with -INKOG H ink betterthan good foun- $ j pens. Won’t skip. 4 blot, scratch, teak, coe or all hands, Makes 4 carbons. 14 kt. gold point, shaped like fine lead encil point. Guaranteed. SEND NO MONEY. Pay postman $1 plus postage. bg 1 wanted. INKOGRAPH co. »inc., 189Q Centre St.,New York iS This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31. ma ere anc wh als ter enc pla cor pla to. tap wa adi ver fine 2“ fl fh mn i AT |

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red by 17, 10- nly for | radio ement | ig care ’ send- - portrait on ev! tion all, Micite Better Shop Sine Bar and Parallel Aid in Accurate Tool Work SINE bar’s accuracy is dependent upon the care taken in making it. Several styles are available and they are made in various sizes. The design shown below is my own pref- erence. It is made of tool steel hardened and aceurately ground. The buttons, SURFACE PLATE The sine bar is used in conjunction with a special square cast-iron parallel block which are both the same size, are hardened also and ground. Each is held in place with a short pin that screws into the cen- ter. Holes are drilled and tapped in each end of the bar for locking the buttons in place with a setscrew. The square, cast-iron parallel is used in conjunction with this sine bar. It is planed square all around and then ground to. size. A series of holes is drilled and tapped in one side and the bar is fastened to the parallel with a single screw and washer. Gage blocks can be used to best advantage for setting the angle. The sine bar and parallel make a con- venient set for a toolmaker working on fine tool and gage work.—H. L. W. Simple Pipe-Bending Fixture AX EFFICIENT pipe-bending fixture that can be cheaply constructed is shown below. The fixture may be bolted to a bench or wooden block or moved about as necessary. The base is a piece of cast iron planed on one side. The formers and rollers are! CAST-IRON BASE ' 1'2"X 8X18 The assembled pipe-bending tool and details of the levers and forming rolls made as detailed. Each former is fastened to the base with 2 countersunk head Screws. The stops are riveted to the under side of the formers. The levers may be any suitable length, but short levers are preferable if the fix- ture is to be carried from place to place. Additional leverage can be had by using pipe-extensions. POPULAR SCIENCE MONTHLY Thomas A. Edison and Charles P. Steinmetz in the Schenectady laboratories of the General Electric Company, where Dr. Steinmetz did his great work. Steinmetz The spirit of Dr. Steinmetz kept his frail body alive. It clothed him with surpassing power; he tamed the lightning and discharged the first artifi- Emerson tells howthe mass of men worry themselves into nameless graves, while now and thena great, unselfish soul forgets himself into immortality. One of the most inspiring in- fluences in the life of amodern corporation is the selfless work of the scientists in the laboratories, which it provides for their re- search. cial thunderbolt. Great honors came to him, yet he will be remembered not for what he received, but for what he gave. Humanity will share forever in the profit of his research. This is the reward of the scientist, this is enduring glory. GENERAL ELECTRIC , “WONDER” COLD PIPE, = TUBING & SAR BENDERS HAND and MOTOR OPERATED 14 Sizes of Machines What it costs to bend pipe our way. Fer bend. 7 ino a6 i ae ** pipe Bcents 4°” pipe cents Resa 2’’ pipe 10 cents 6’’ pipe 60 cents 8’’ pipe $1.00 Send for Catalogue. AMERICAN PIPE BENDING MACHINE CO. 51 Pearl St. Boston, Mass. TOOL CASES for MACHI 2 ISTS TOOL MAKERS are shown in our new 1925 catalog. Thirty styles and sizes shown. A postal brings ® the catalog. H. GERSTNER & SONS 513 Columbia St., Dayton. 0. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31. EasytoDraw Cartoons When Shown in the RIGHT WAY Some of the cleverest cartoonists and comic artists learned how_to draw in their spare time by following Cartoonist Evans’ Simple and Easy to Learn Method and are now MAKING GOOD MONEY. Send one of your drawings, and let Mr. Evans see it you have ability and receive the Portfolio of Cartoons and ful! details about the course. It is not expensive. THE W. L. EVANS SCHOOL OF CARTOONING 825 Leader Building Cleveland, Ohie

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~ INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7634-D, 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 an X: BUSINESS TRAINING COURSES Business Management Salesmanship Industrial Management Advertising Personnel Organization OU Better Letters Traffic Management (Show Card Lettering Business Law (] Stenography and Typing Banking and Banking Law CJ Business English Accountancy (including C.P.A.) (J Civil Service Nicholson Cost Accounting Railway Mail Clerk Bookkeeping Common School Subjects Private Secretar High School Subjects oOoooooonooo Spanish French Dlustrating TECHNICAL AND INDUSTRIAL COURSES Electrical Engineering CO Architect Electric Lighting CO Architects’ Blue Prints Mechanical Engineer [j Contractor and Builder Architectural Draftsman Concrete Builder Structural Engineer Chemistry 0 Pharmacy Automobile Work Airplane Engines O Agriculture and Poultry (J Mathematics Mechanical Draftsman Machine Shop Practice Railroad Positions Gas Engine Operating Civil Engineer Surveying and Mapping Metallurgy 0 Mining Steam Engineering () Radio

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QoeCUPAtIOR..0cccecescccccccccecoccecereesesceees Persons residing in Canada should send this coupon to the International Correspondence RA Schools Canadian, Limited, Montreal, Canada

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RAP ett RF REE! ee eee 53.) Por broadcasting stations and other valuable dawn Send . mame and eccees, we pene ee 50c book FREE! F R A \\) wre SaHanA Wil ap pon sabre Seer balee eosiere.and fama \* . GE Pom This service FREE to our customers’ Wrne today’ zt NORWALK RADIO CORP Dept. 54 66 READE ST., NEW YORK CORONA FOUR With standard office keyboard—anoffice typewriter in port- able form. Write for literature. Corona Typewriter Co., Inc. 112 Main St., Groton, N.Y.

POPULAR SCIENCE MONTHLY January, inn,

Special Tool-Holder Aids in Many Boring Jobs HERE are times in the small shop when it is difficult to find a machine to do a boring job quickly. In order to make use of a milling machine or a lathe for this class of work, the boring tool- holder illustrated is useful. At the same time it is considerably easier to make than many other devices that operate on the same principle. The piece to be bored is fastened to the lathe slide or milling-machine table and the tool-holder is screwed to the lathe or milling-machine spindle. Two castings and a screw with an ad- justing knob are required; a single pat- One simple pattern serves for the two castings needed in making the tool- holder

tern will answer for both castings. The back casting is bored and tapped to suit the spindle on which it is to be used. It is dovetailed to a neat sliding fit with a front, or tool, casting. The boss on the front casting should have either a round or square hole for the cutting tool, which is held in place by a setscrew. A 14- or 34-in. screw is used for adjustments and the end of the front casting is tapped to suit it. To assist in setting the tool, inch marks may be marked on both the castings. Start at the center line and mark away from the knob end.—F. N. C.

Bench Vise Used in Milling 6 ike of the simplest ways to use a lathe for milling is that illustrated, which is a method used in a small Washington, D. C., repair shop. A small bench vise is bolted temporarily to the saddle of a lathe carriage in place of © the toolpost. The work is clamped in the vise jaws and the tool is fixed in the lathe MILLING CUTTER IN LATHE SPINDLE VISE SECURED TO TOOL CARRIAGE OF ‘he

The work is held in an ordinary bench vise bolted to the lathe saddle headstock spindle. End mills, face mills, and either circular saws with the usual taper shank or saw mandrels may be used by this method. Practically any shape of milling cut can be made by shifting the position of the work in the vise and using the feeds of the lathe carriage.

IS} This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31.

One of the best ang complet ast on the markets et GENUINE $60 vaiye 1338, For Handy Man ond Mechani With this “little sawmill” you can make your own re- pairs in shop, home, farm or garage. In 1001 Ways it will save its cost many times over. Makes a clean edge on the toughest wood—no planing necessary Rips, crosscuts, bevels, miters, mortises, tenons, or grooves quickly and accurately. Does the work of a skilled mechanic and saves you time, labor and money. MECHANICS’ BENCH SAWS Can be attached to any lamp socket. Weight only 61 lbs. This saw will cut up to 14”. Indispensable to wood workers, carpenters, cabinet makers, pattern makers, model makers, inlaid floor makers, hardwood floor finishers, picture frame makers, farmers printers, radio builders, schools, colleges, homes, ete. All metal. Saw-size 6 inches. Table 10x13, base 7x1{. height 7 inches. Table tilts for beveling 5 degrees left, 10 degrees right. Hinged top for cutting grooves tenons, rabbets. Bearings solid bronze with grease cup lubrication. Guides removable and adjustable rip and cut-off. Sunlight 4% h. p. motor; 110 volts: 60 cycle; 4.5 amps; 1750 R. P. M. Current A, ¢’ Centrifugal switch with auxiliary finger. High grade steel shaft with ground bearing surface. Water and moisture proof insulating material used throughout, Exterior connections to allow change of direction of rotation. Large grease cups with wick lubrication, Bearings of Bunting phosphor bronze metal. COMPLETE OUTFIT $3 A including cord, plug, pul- ley and belt, everything com- $60 VALUE East of the Mississippi plete, ready to attach. The saw furnished with this outfit We pay delivery charges, $38 west of the Missis- is the Disston 6’ Novelty Combination Cross Cut and Rip Saw, guaranteed to run without set. No planing or sanding required after cut- ting. bend ” equipped with extra heavy duty motor guaranteed to handle 50% sippi. We pay Ccelivery overload. charges. SAW TABLE “sacagh <4 aurcheres with 6” saw or -90; we pay delivery charges anywhere in the U. S.-- $22.50 MOTOR This heavy duty Motor can be fur- nished separately for $15.90; Guaran- teed to handle 50% overload; we pay de- $15, 90 livery charges anywhere in the U. S.--. 2 This SUNLIGHT 1/4 H. P. Motor Complete with Cord Piug and Fiat or Grooved Pulley 12" Regular Value $30 We delivery char- kes anywbere ein the 110 volts; 60 4.5 amps; 1780 P.M. Current A. Guaranteed to dle 20%, overload. HARDWARE HEADQUARTERS of Philadelphia Philadelphia, Pa.

le 4 c: o : PAUL J. DEVIT 1101-1113 South 2nd Street,

Containinz a full line of complete outfits and parts at exceptionally low prices. rite immediately to

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va ro th ta hi; sti

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TY, 1925 ) VALUE € LUE hi a 1 Missis- y Celivery . h 6” saw 22.50 | be fur- Guaran- s LIGHT Motor and Fiat d Pulley january, 1925 POPULAR SCIENCE MONTHLY 133 Fpetter Shop Methods. Adjustable Angle Plate for Use on Surface Grinder HE cast-iron angle plate illustrated is for use on a surface grinder in fine tool and gage work. It must be ma- chined and ground accurately. © The plate will swivel to either side through an are of 45 degrees. It may be 4 HOLES- } REAM ~ a A7*. GRADUATE IN ee 2b OSG “yp, - DEGREES gs pic > OCCAST-ARON © This angle plate will swivel on either side through an arc of 45 degrees held on the magnetic chuck of the grinder or fastened to the table with a bolt. Four accurately located holes are drilled in the top surface for pushpins, so that work placed against the pins can be removed and, if necessary, replaced in the same position. The pins are 4-in. drill rods and should be a push fit in the holes. The work is clamped on the angle plate. Box Tool-Holder for Tailstock N QUANTITY production on small studs, screws, dowels, and a large variety of other work made from cold- rolled steel and brass stock in the lathe, the time lost in making tool changes and taking individual measurements results in high cost and slow progress in the work. Tool methods for quantity production are not necessarily a matter of intensive study or expensive construction. Fre- ILLUSTRATING LATHE SET-UP FOR MAKING STUDS SECTIONAL ‘SPECIAL BOX TOOL HOLDER DP A 4 / cb y Y _ How the tool-holder is used and sectional details showing simplicity of construction quently some simple and direct means to set up tools jointly is available. An example of a tool set-up for brass studs is illustrated. The feature is a simple box tool-holder for mounting two tools in the tailstock. One end has a taper shank and the other is cylindrical in shape, with two transverse slots to accom- modate two turning tools, these being held by setscrews. The tools can be removed for grinding, or the position altered as required for turning work within the capacity of the circular opening. At the rear of the tools is a simple stop adjusted by adding washers under the screw head.—A. G. —___ FOUR TUBES—ONLY ONE DIAL ADIO is revolutionized by this new receiver! A four-tube set whose loudspeaker rangeis practi- cally unlimited. Exquisite, na- tural tone. Extreme sensitiveness and selectivity. And extremely simple opera- tion—single dial control. Built as only Paragon sets have been built in the past. But basically new, employing the new non-radiating Para- dyne Circuit. And one third the price you would expect to pay. The new Paragon line includes the new PARAGON TWO, $27.50, a two- tube set of excellent loudspeaker tone and volume from stations within moderate radius. And the new PARA- GON THREE, $48.50, an exceptionally sensitive, fine-toned, three-tube receiver. Ask your radio dealer to show you these new receivers. ADAMS MORGAN COMPANY, Inc. 2 Alvin Avenue, Upper Montclair, N. J. You've heard your neighbor praise this wonderful weekly mag- azine that 3 million peopleread, Unbiased digest of national and world affairs. Chock full of just the kind of reading you want. Sci- > ence, politics, travel, fun, fashions, — question box, books, health—entertainment and instruction for all. Send 15c (coin or stamps) today for this big paper on trial 13 weeks or $1 for 1 year (52issues), PATHFINDER, 559 Langdon Sta., Washington, D.C. ISN SELL RADIO SETS PARTS, BATTERIES, ETC. Big money can be made. Write for our complete big catalog and particulars.—FREE! SPECIALTY SALES CoO. Dept. E, Greeley Street, Milwaukee, Wis. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31. *‘Saws in the Shop,” ‘‘Saw Sense,” “Saws on the Farm.’’ Just send us your name and address and say which of these helpful books you want and we will send it FREE. Write NOW. E. C. ATKINS & CO., Inc. Dept. D-20 Indianapolis, Ind. js Direct from or our factory to wearer. P Easily sold. Over one million gat- " isfied wearers. No capital orexperience g required. Largesteadyincome., Many earn $100. to $150. weekly. Territory now being allotted. Write For Free Samples. ’ _ MADISON SHIRT M’F'RS, £05 Broadway, New York

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134

POPULAR SCIENCE MONTHLY

Electricity Needs Let MeTrain , You to Filla | Big Pay Job (* No matter what kind of work you are doing now, or how much you earn, electricit offers you more—a better jo and bigger Pay is waiting for you. Trained Electrical Ex- perts are in great demand at thehighest salarieseverknown. The opportunities for ad- vancement and a realsuccess are amazing. The enormous rowth of the electrical in- ustry snaps up men faster than they can be trained. Elec- tricity needs you. Electrical Fe c.>. 5 Ore., makes $' @ year Ex jn Automotive Electric: Earny12 a Day ae eal { will train you at home in your spare time to earn this e big pay just like the men whose pictures you see here. In a few short months you will be ready fora wonderful HERBERT DICKER- job that I will help you get. aie Va., ack of education or experi- &°% & year. ence doesn’t bar anyone. My simplified, up-to-the-minute, easily learned course, backed up with my 20 years engineer- ing experience, guarantees your success, Electrical Tools and Meterial I will give you free a whole outfit of electrical tools, material, J. R. MORGAN, Co- measuring instrumentsandarea} lumbus, Ohio, makes electric motor—not toys, but tha $30 to $50 a day in busi- realthing,suchasnootherschoot ness for himself. has ever offered before. I will start you right in after your first few lessons doing practical work in a practical way—work that will y you extra money while youare learning and from $3,500 to $10,000 @ year when you are trained. Satisfaction Guaranteed I don’t merely promise you these things—I guarantee them. I send = a signed bond guaranteeing return your whole tuition fee— every penny you pay me—if you A. SHRECK, Phoenix, are not 100 per cent satisfied af- Ariz. gets over$20 a day ter finishing my cotrse. out of electrical work. Investigate! Mail Coupon Get the Vital Facts. Let me send you _ 2 Sree my big new book on The Future a of Electricity. Let me tell you more about / the “‘Cooke’’ Electrical Experts, ‘ methe Couponbelow, ea 2 ma} dip

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cy ne! NV ants re’s a ar al and turn a nstrate 1 sale, success Oliver ites n use. mplete range, er is a > want ons, to rtising yw you > ER [ON oducts urners , Evel Price $3. rk City Better Shop Methods Universal Milling - Machine Punch for Laying Out Work MILLING MACHINE ARBOR f BRACKET ON STATIONARY (| ? DISK ROTATING DISK é —— , \2 WDZ ROTATING SPRING ze Sa H - tee _PUNC Wii — pisk AND STUD sa IN-ONE PIECE TRANSFERRING “| WORK —? [ oatitiedl =a" This punch serves for marking and trans- ferring points in milling-machine layouts FRE punch illustrated, which is at- ‘tached to the arbor of a milling machine, is a universal tool for laying out work that has been set up for milling oper- ations. It is used for center punching the location of holes, transferring these marks to opposite points, and similar pur- poses. The punch may be set at any angle quite accurately by means of the scale on the body of the tool.— HENRY §. LaRABy, New Haven, Conn. Special Hanging Tongs Speed Work of Case-Hardening HEN only one end or a part of small pieces are to be case-hard- ened and there is a large amount of work to be handled, the method illustrated saves much time. AA|AZy One or two tongs Za “ are made, each with a_ special hooklike handle and a sliding link. The hook fastens Hooxon into one of a series , of holes drilled in a length of 14 by 1 in. iron, and this piece is hung from another length of iron. An elongated slot allows the lower piece to be adjusted up and down. The piece to be Wize, vardened is DD hyeNS gripped in the aR tongs by means of perdepth inleadbath the link. If two pairs of tongs are made, one piece may be heated while the other is being dipped or tempered. ADJUSTING gh SLOT “ Y HOLES } APART © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31. POPULAR SCIENCE MONTHLY Ean It’s Easy to Build a five tube radio frequency receiver when you use the Freshman Masterpiece Kit SELF BALANCED LOW LOSS TUNED ’ FRE: FREQUENCY: KIT WILL NOT ESHMAN FULLY QUARANTEED D THIS TAG OScILLATE | MASTERPIECE | 223i & NUMBER IS ON EVERY BOx 3 MASTERPIECE TUNED RADIO FREQUENCY UNITS Se unuchsn n's etre cer acmaamgencnae YY 7 SO. WIM dee ZI \g : No Neutralizing or Balancing Condensers Required when you build with this kit to produce a radio frequency receiver that will bring in even the most distant stations with the volume and clarity of locals. So selective that stations can be brought in day after day at the same dial settings. A set that will be the equal, if not the superior, to any 5 tube receiver on the market, and what’s more, it’s extremely simple to operate. Kit consists of 3 Masterpiece Tuned Radio Fre- quency Units carefully matched and balanced. Complete with wiring diagram and instructions % 50 for building any 5 tube tuned radio frequency re- ceiver and also drilling template for proper mounting Swe me se fal om GY ee ee Each and every Freshman Masterpiece Coil bears a serial number and Trade- mark—our guarantee of electrical and mechanical perfection. Every genuine Freshman Coil is made of specially insulated wire to prevent short-circuiting, so often caused by inferior coils. For your protection demand only the genuine. At your dealer’s, otherwise send purchase price and you will be supplied without further charge. 106 Seventh Ave., Chas. Freshman Co., Inc., new yvor« a Imperial i Put on like Plaster PATENTS 22sec: | Sento ears ike Iron consistent charge, a , service noted for results, evidenced by many well known -water Pp roof Patents of extraordinary value. Book, Patent-Sense, free. } f i re oO f Lacey&Lacey, 648 F St.,Wash., D.C, Estab. 1869. 2, proo =\resilient BLANK CARTRIDGE PISTOL tection against Burglars, Tramps, & Dogs PRICES ‘4 A composition material easily applied_ in plastic ;, form over practically any kind of floor. Laid 74 about % inch thick. . Imperial Floor does not A crack, peel, or come loose from foundation. A continuous, fine grained, smooth, non-slipping surface. No crevices to gather grease, dirt, dust, disease germs or moisture. Ideal Floor for Kitchen, Pantry, Bath Room, 7; Laundry, Porch, Garage, Restaurant, Theater, § 4 Hotel, Factory, Office Building, Railroad Station, ee 4 Hospital—wherever a_ beautiful substantial floor yw) 4 is desired. Several practical colors. Full in- 9 v7, formation and sample FREE of your first and second choice of color. Imperial Floor Co.,364-366 Halstead St., Rochester, N.Y iia A Success for 15 Years Well made and ef- fective; modelled on latest type of Revolver; appearance alone is enough to scarea burglar. When loaded it may be as effective as a real revol- bac Th \ Price 50c. quality $1.00 Postpaid, Kapaa ) Blank Cartridges, by express, 50c per 100. Johnson Smith & Co., Dept. 281, Racine, Wis.

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136 POPULAR SCIENCE MONTHLY

Re PATENTS— and Patents t is not unusual to find an in- ventor who believes that the degree of protection afforded by a patent depends upon the merit of the invention. Such is not the fact. The strength of a patent lies in the breadth of the claims that have been allowed by the Pat- ent Office. These in turn depend upon the care and skill with which they have been prepared and prosecuted by the patent attorney. w Trademarks are even more val- uable than patents in many cases. It is essential that their registry be placed in expert hands. The standing of Munn & Co., identified with the publication of the “Scientific American,” has been earned in a continuous practice of nearly eighty years before the Patent Office. The facilities and resources they have accumulated in that time are at the disposal of individuals and business houses at fees that are as moderate as conscientious | service will allow. Write for Munn & Co.’s book on | Patents. A succinct and accurate

booklet of information on Patents, Designs, Trademarks, Foreign Patents, Copyrights, Labels and Patent Office Practice. It also de- | scribes the methods and the terms of Munn & Co.

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brass bound lenses. ‘Usefu ane sate miles away.’’-Mrs. h. **Watch my y arrive at school 2 miles eway.’’—Mrs. H **Kead numbers on freight cars mile away, see mppuntsine on : . C._ Palmer. Thousands pleased. A Send No W tite today: on arrival of Big 3 ft ‘Wonder . Telescope, with F FREE rai te lase and 5 Money Strap pa: Postman o onl, $1. as a few Satist fac! FERRY & COP S254 Haisted Sts Dept. 1781, CHICAGO

Sliding V Wased: iene as Counters for Tally Rack \ , 7 HEN drawing gasoline from storage tanks for motor vehicles, an accu- rate check on the amount used can be kept by utilizing a tally rack similar to that used for billiard scores. The rack consists of a length of round iron or steel supported by two wooden brackets that are attached to the wall AM DRAWN wT) REMAINDER PR pened ——— eee WY” <4 Tywes AS MANY SMALL WASHERS AS LARGE ONES

M_ ¢!RON ROD

Designed after a billiard tally rack, this device keeps account of gasoline near the gasoline pump. A number of iron washers, representing the number of gallons in the tank, are placed on this rod. To simplify the counting, every fifth washer is.of larger outside diameter. One washer is moved on the rod for each | gallon of gasoline drawn out. The store- | keeper then can tell at a glance when to | order the main tank.—S. H. SAMUELS.

How to Repair the Worn Rack on a Power Hacksaw HE rack on almost any power hack- saw that has been in use for scme time will be found to be worn down so that it is very difficult to get the ratchet on the vise jaw to catch in the rack. The ratchet generally will be worn off ' until the handle sags enough to allow it to strike on the metal frame with each turn, which also raises the dog until it slips out of the rack. Since the rack is an integral part of the vise, it is usually considered impracticable to However, two saws

A repaired rack attempt a repair. | have been fixed as shown. The casting of rack and jaw was placed in the shaper and the old rack cut out, leaving a smooth slot. A new rack was milled in a bar of steel and bolted in place, a new bolt hole being required at the jaw end. The rack was cut longer than the old one, as shown, so that the end bolt in the frame could be used. Because it had been worn blunt, it was necessary to forge the end of the-ratchet to a better point.— HAROLD E. BENSON.

Smoothing a Lathe Center [% SMALL shops where there is no center grinding attachment, much time can be saved when a lathe center becomes rough through running hot, by placing a little powdered emery on the center before the next job is started. Care must be taken to keep the center up against the work, or the emery will grind all on one side. While this leaves a ring on the center, the method serves well in an emergency, in fact, it will be some time before it becomes necessary to anneal and true up the center.—G. E. S.

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

See page 31.

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POPULAR SCIENCE MONTHLY > an @ VENTORS: PROTECT YOUR IDEAS:WRITE FOR THESE FREE BOOKS : bo > t.—_4 VE -Py we me TRADE MARKS-COPYRIGHTS ANY NEW article, machine, design or improvement thereof, or any combination of parts or improvements in any known article which increases its efficiency or usefulness, may be patented, if it involves invention. If You Have Any New Ideas which you feel are useful, practical and novel, take prompt action to protect your rights. If you have invented any new machine or new combination of parts or improvement, or any new design or process, send drawing, model or de- scription of it for information as to procedure to secure protection.

All communications are held in strict confidence. My personal, careful and thorough attention is given to each case. I offer you efficient, reliable and prompt service—based upon practical experience. Highest references. No / charge for above information. / Write today for free books, ‘‘How to Obtain a Patent’’ and “Inven-<_— tion and Industry” and blank form ‘‘Record of Invention.”’ ie These books will give you valuable information, and they may save you much time and effort. Send for them now. My practice is devoted exclusively to United States and Foreign Patents and Trade Marks. Write me freely, frankly and with full confidence; it is very probable that I can help you. Use the Coupon attached, and immediately upon its receipt I shall send you the form Record of Invention to be returned to me with drawing, description or model of your idea; promptly upon re- ceiving your idea I shall write you as to procedure and costs. CLARENCE A. O’BRIEN REGISTERED PATENT LAWYER Member of Bar of Court of Appeals, District of Columbia, United States Court of Claims; Supreme Court of United States, Supreme Court District of Columbia. PRACTICE CONFINED TO PATENTS, TRADE MARKS AND COPYRIGHTS --------------- FREE COUPON ---------------- CLARENCE A. O’BRIEN, REGISTERED PATENT LAWYER 889A Security Savings and Commercial Bank Building Directly across Street from Patent Office, Washington, D. C. Please send me your free books, ‘‘How to Obtain a Patent” and ‘‘Invention and Industry” and blank form, ‘‘Record of Invention,’’ without any obligation on my part.

IMPORTANT— WRITE OR PRINT NAME CLEARLY.

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31.

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138 A tobacco that never changes, deposes Mr. Bruce Mr. Bruce doesn’t know of the eternal vigilance that its makers exercise to keep | “good old Edgeworth’ unchanged in quality. But it is our conviction that a man buys the next tin of Edgeworth be- because he liked the one before it. Therefore, it is up to us to see that he gets what he is trying to buy—‘‘more of the same.”’ And Mr. Bruce is well qualified to testify on this point. He tells us that he averages better than half a tin a day, and he has been smoking Edgeworth for eight years. Let’s see—that’s something like i461 tins for Mr. Bruce, according to our office ealculator. But Mr. Bruce’s own letter will be more interesting than our com- ments. Here it is: Savannah, Ga. March 14, 1924, Messrs. Larus and Bro. Co. Richmond, Va. Gentlemen: I have been using Edgeworth since 1916 and think it is the best pipe tobacco on the market. The flavor and aroma are distinc- tive; the quality, being the very best, never changes; and as I have smoked nearly every brand of pipe tobacco mac“, I have never found its equal. My pipe is in my mouth nearly every hour of the day, and I smoke continually, using a can in less than two days, but have never felt anv bad effects from Edgeworth. I have the best smoking combination there is—a can of Edgeworth anda BBB curve stem—and these two friends, hav- ing been with me for eight years, are going to be with me as long as I live. Wishing you and Edgeworth the best of success, I remain, Yours very truly, (signed) F. K. Bruce, 705 East 39th St. Let us send you free samples of Edgeworth so that you may put it to the pipe test. Write your name and ad- Brother Com- pany, 101 South 21st Street, Rich- sizes to suit the needs and means of all purchasers. Both Edgeworth Plug Slice and Ready-Rubbed are packed in small, pocket-size packages, in handsome humidors holding a pound, and also in several handy in-between sizes. We'll be grateful for the name and ad- dress of your tobacco dealer, too, if you care to add them. To Retail Tobacco Merchants! If your jobber cannot supply you with 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. dress to Larus & | Better Shop Methods | of the planed faces. | right.” | that far!’ Bob laughed, and went on with | his work. : mond, Va. Edgeworth is | sold in various | planed surface, Bob,’’ Old Bill said. He | ends so that they are the finished dis- | tance G@ (Fig. 8) from the center of the | the lathe,” the first answered. POPULAR SCIENCE MONTHLY How to Handle Rush Repairs (Continued from page 94) dimensions (Fig. 4). He showed Old Bill that he had his center line exactly in the middle of the two finished faces. **Now let us transfer a center line to the took a long straightedge and two squares, as shown in Fig. 5, and drew a line on one “We could take a square and make a line at right angles to this one, but I had rather do it with the dividers, for we are not taking such a chance on something slipping,’’ Old Bill continued. Then he took the dividers, and drew ares on the ends of the jaws, using as a center a point C (Fig. 6) on the center line that he had just drawn. Then he drew another arc on each of the jaws, using as center the point D, that he had made in the beginning. E MEASURED from the inside of the cored recess in the casting and located the point F (Fig. 7), which is the center line of the pinhole. “Set up the casting so that you can plane off the ends of the jaws,”’ he said. “Use these two points E, that we have just made to set up by, and plane off the pinhole. Be absolutely sure that you have the set-up right and that the planer cuts squarely down the face. Check it up again before you take the final cut, and don’t plane off the marks E. Make some more, if you have to take off that much, for we want to be able to know that we are Somehow or other a good many of the machinists in the shop seemed to have business around that planer this morn- ing. They wanted a bolt, or a tool- holder, or admitted that they just wanted to watch Old Bill lay out the job. ‘*He gets those lines drawn just where he wanted them the first time,” one of the interested onlookers said to Bob. **T saw Conley laying it out,’’ another observed, ‘‘and he did not plane that end off at all.’ “*He said that he could do it quicker in ‘“Maybe he could, but he didn’t get When Old Bill returned, he was leading a couple of men with a truck. They were bringing up a big angle plate that was kept in the toolroom to protect it against damage. | “Now, Bob,” he said. | come to a very particular part of the job. | Set up the angle plate on the table, and | line it up with the stroke. Bolt the cross- | “You have head to it so that you can plane the sur- face where the gibs fit on. Put the bolt through one side of the pinhole and leave | the other side open so that you can put in a block of wood and find the center | again. Get the angle that these faces | make with the ends of the jaws, and care- | fully set up the casting. If you make a little error, there is a chance of correcting | it, but we don’t want any error at all. (Continued on page 139) January, 19, ee PENN EUR TEND dip an DON’T LOSE YOUR RIGHTS TO PATENT PROTECTION ii §©«©Before disclosing your invention to anyone Wa send for blank form ‘‘EVIDENCE OF Con. if CEPTION”’ to be signed and witnessed, | 4 Mf sample form together with printed instructions Ma will show youjust how to work up youreyi. ij dence and establish thesame before filing ap. MW plication for patent. As registered patent at. iq torneys we represent hundreds of inventors al] Mm over the United States and_Canadainthead. MW vancement of inventions. Our schedule of fees # willbe found reasonable. _The form ‘Evidence M of Conception,” sample, instructions relati to obtaining of patents and schedule of fees sent upon request. Ask for them,—a post card will do. PATENTS AND NX TRADE MARKS Registered Patent Attorneys in U. S. and Canada 274 Ouray Bldg. WASHINGTON, D. C. Originators of forms “Evidence of Conception.” age - . saa > “~~. . To the Man With an Idea I offer a most comprehensive, ex- }f perienced, efficient service for his if prompt, legal protection and the development of-his proposition. Send sketch, or model and description, for advice as to cost, search through prior United States patents, etc. Pre- : liminary advice gladly furnished with- | out charge. | My. experience and familiarity with various arts, frequently enable me to accurately advise clients as to prob- able patentability before they go to any expense. Booklet of valuable information and form for properly disclosing your idea, free on request. Write today. RICHARD B. OWEN Patent Lawyer 6 Owen Building, Washington,D.C. 2276-D, 41 Park Row Cortland 0721 New York City PATENTS TRADE-MARKS, COPYRIGHTS AND PATENT LITIGATIO Write for advice and instruc- tions how to proceed, costs, etc. 4 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. 681A Ouray Bldg. WASHINGTON, D. Cy PATENTS BOOKLET FREE HIGHEST REFERENCES PROMPTNESS ASSURED BEST RESULTS Send drawing or model for examination WATSON E. COLEMAN, Patent Lawyer 644 G Street N. W., Washington, D. C. | and report as to patentability {© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31. Hot Put a the ot not m you tl H (Bi this 01 setting Then | TW qui castin workil some | ends ¢ with ¢ vent § put a with | spindl again:

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ary, 1995 TS january, 1925 —————_ aan —74 er Shop Methods How to Handle Rush Repairs ‘sok under the boss end, and brace ead to the table so that it will not move. Put on some other clamps, if you think it necessary. Get the distance H (Fig. 9) from the old one, and make this one like it. Be sure and check up the setting before you finish the surface. Then we shall be ready for the lathe. T WAS just a little bit after the usual I quitting time when Bob trucked the casting to the lathe. But he kept on working, for he knew that Old Bill wanted some overtime put in. He put the planed ends of the jaws up against the faceplate with a thickness of paper between to pre- vent slipping. He found a long rod and put a clamp through the pinhole so that with his long rod all the way through the spindle he could pull the casting up tight against the faceplate. When Old Bill came up, Bob was setting the casting from the edge of the faceplate, using his finished surfaces to measure from (Fig. 10). “This faceplate runs true,’’ Bob said. “T tried it before I put the casting up.” “You had better put some clamps around the edges so that you will not have to depend entirely on friction to drive it,’ Old Bill said. “‘I think that if you bore and chase the hole tonight, you will have done enough. There is a mandrel all ready for the crosshead; you can use it to fit the thread to.”’ So Bob completed his setting, and then carefully cleaned up the edge of the piston hole so that he could put up a bull center. “Have to go easy on this,” he said to his helper. “It will be different when I can support this end, but I don’t want to take any chances until then.” He put up his bull center and turned the outside of the boss. He put up a steady rest on the outside of the boss and bored out the hole. Old Bill had given him some good advice on how to get good threads, and he had not forgotten it. | So, a little before midnight, he and his | helper went home. [N THE morning Old Bill came around and tried the mandrel in the thread. “Tt seems to be a good fit, Bob,” he said. “Take it out so that I can see the thread.” “T don’t think you will find any fault with that thread,” Bob said, as he screwed the mandrel out of the hole. “It does look good,” Old Bill com- mented. ‘Now get the pinhole bored so that we can get the pin fitted; then put the shoes on, and we shall be able to ship the job today, all right.” Laten quickly took the casting out of the lathe, and took down the steady rest. He cleaned off his faceplate and put the casting back with the long bolt he had used before through the pinhole. “How are you going to bore that hole with a bolt in it?” his helper asked. “It’s a trick Old Bill taught me long ago,” he said. ‘Whenever there is a piece (Continued from page 138) | POPULAR SCIENCE MONTHLY Have You An Idea? Our Offer: Ne,ch2rse fer, examina- Protect Your Invention Your first step before disclosing or submitting your invention to anyone either for entry in a prize compe- tition or for sale should be to write for our blank form “RECORD of INVENTION” This should be signed and witnessed and returned to us together with model or sketch and description of the invention for examination and instruction and to establish Evidence of Conception. No charge for the above information Our Four Books Mailed Free to Inventors Our Illustrated Guide BOOK How to Obtain a Patent Contains full instructions regarding U.S. Patents. Our Methods, Terms, and 100 Mechanical Movements il- lustrated and described. Our Trade Mark Book Shows value and necessity of Trade Mark Protection. Information re- garding Trade Marks and unfair competition in trade. Our Foreign Book We have Direct Agencies in Foreign Countries, and secure Foreign Patents in shortest time and lowest cost. Progress of Invention Description of World’s Most Pressing Problems by Lead- ing Scientists and Inventors. WE REGARD A SATISFIED CLIENT As our best advertisement, and will furnish to anyone, upon request, lists of clients in any state for whom we have secured patents. Communications Strictly Confidential. Highest References—Prompt Attention— Reasonable Terms of work to be set up and clamped, always set it up and clamp it from the largest | diameter that you can. I am going to | (Continued on page 140) | WRITE TODAY: Free | VICTOR J. EVANS & CO. Patent Attorneys New York Offices Philadelphia Offices Pittsburgh Offices 1007 Woolworth Bldg. 714-715 Liberty Bldg. 514 Empire Bldg. oupon Chicago Offices, 1114 Tacoma Bldg. San Francisco Offices, Hobart Bldg. Main Offices: 760 Ninth Street, Washington, D.C. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See Page 31, Gentlemen: Please send me FREE OF CHARGE your books as described above. I SES 2 A a eee eon ace ga ed a ee Address CECH CSCO :0C46 O64 0.06 @ 6e ee

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EARLE E. LIEDERMAN The Muscle Builder “Thou Shalt Not Kill’’ is the most gruesome commandment handed down to mankind. A man may lie, steal or break any other law and the public will eventually forgive and forget. But tet him commit murder and the cry of everybody is to give him the full penalty—Death! And what is the common excuse of the murderer? INSANITY! Sure, he’s crazy. Any man must be crazy to commit murder. But how about the fellow who slowly but surely kills his own body by neglect? He's the craziest one of all. Stop! Think this over! What are you doing with your own body? Surely you don’t want to be put in this class. But if you are not doing everything possible to prolong your life and keep your body just as clean and healthy as your Maker intended, you are inviting death. You are slowly but surely killing yourself. A New Life Have you ever enjoyed the pleasures of perfect health? Have you ever felt the thrills which accompany a strong robust body? If not, you have nature’s biggest gift awaiting you. That is what I have to offer you. I don't promise to feed this to you in pill form. No, you have to work for it. You can’t get anything in this life without effort. Don't let anyone fool you by telling you different. I’m going to make you work, but oh boy! how you'll like it. After a few days you will feel the old pep shooting through your veins and you will crave your exercises like a kid wants his bread and sugar. Today Is Your Day This is your birthday. Today you start a new life. I'm going to make a real live, ‘‘rip-snortin’,’”’ go-getter out of you. I’m going to expand that chest so it will give your lungs a treat with life-giving oxygen. This will put real vim into your blood and shoot it throughout your entire system. I’m going to broaden your shoulders and strengthen your back. I’m going to put a ripple of muscle up and down your body that will make a big powerful he- man out of you. You wi!l have the arms and legs of a modern Hercules. I'l! clear your brain and pep up your entire system. You will be just bubbling over with vital- ity. You will stretch out your powerful body and shout for bigger and greater things to accomplish. Nothing will be too difficult for you to tackle. Sounds good, doesn’t it? You can bet your Sunday hat it’s good. It’s wonderful. And it’s no idle prattle either. I’m not promising these things. I guarantee them. Do you doubt me? Make me prove it. Come cn. Atta boy. Let’s go. Send for my new 64-page book ‘“‘“MUSCULAR DEVELOPMENT’”’ It Is FREE 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 pitiful weaklings, imploring me to help them. Look them over now, and you will marvel at their present physiques. This book will prove an impetus and a real inspiration to you. It will thrill you thru and thru. All I ask is 10 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 happiness, do not put it off. Send today. right now, before you turn this page. EARLE E. LIEDERMAN Dept. 1301 305 Broadway New York City oe oe eee ee ee ee ee ee ee a a ee ee ee ee ee EARLE E. LIEDERMAN Dept. 1301, 305 Broadway, New York City Dear Sir:—I enclose herewith 10 cents for which you are to send me without any obligation on my part whatever, a copy of your latest book, ‘‘Muscular Development.” (Please write or print plainly.) POPULAR SCIENCE MONTHLY (Continued from page 139) take a little cut off the four corners (K, Fig. 11). the finished face of the casting, and also with the center line. I will turn the cast- ing around so that I can put parallel clamps. “Tf I had put the parallel under the boss, I could easily tilt it a little at one side or the other. If I did that, I should not have the hole square with the center line. Then the man who will run this engine would wonder what made his crosshead brasses run hot.” | Bob had not noticed Old Bill coming | up, and was rather surprised when he felt a hand laid on his shoulder and heard Old Bill say, ‘“‘I wish that all my men would think things out like that, Bob.” When the casting was turned over, trued up, and securely clamped, Laten took a roughing cut through both jaws of the casting. Then, with his protractor, he measured the angle that the tapered hole made with the face of the casting. He set his compound rest to this angle, and bored the hole, both sides of it. He made the diameter about 1/16 in. smaller than the old one. ““Y THINK that this one has been bored at least once to fit a new pin,’’ Laten it was new. And it is much easier to make the pin fit the hole than it is to try to make the hole fit the pin.” Presently he had the hole bored to his satisfaction. He had taken a very fine and smooth cut through it. He took it out of the lathe again, and laid off the holes for fastening the shoes and for the studs that adjusted the shoes. When these holes, and the hole that formed the keyseat to keep the pin from turning, were drilled, he got the shoes and put them on. Old Bill had given him the diameter of the guides on the first little sketch. He set the shoes out so that he had just a fraction to take off. ‘“‘Want to keep all the babbitt here that we can,”’ he remarked to his helper. He was about to screw in the mandrel when the machinist who was fitting the pin came over. ‘‘Let me try it in once more before you put it in the lathe,” he said. “‘I think I have it just about right.” They put the pin in the hole. The streak of chalk that they had put on the fitting surfaces was all rubbed off, show- ing that the taper fitted from one end to the other. ““Now, when you get the shoes turned, it will take only a little grinding to make it absolutely perfect,’’ the machinist said. ‘“‘T am glad that you made a smooth hole.” It did not take long to get the shoes turned off to the proper size. Laten dressed out the oil grooves in the shoes while the other machinist ground in the pin with fine emery and oil. the crosshead were filed off, and Old Bill had looked it over once more to be sure that it suited him. It did. Then they will be parallel with explained, ‘‘so it is larger now than when | Presently all of the rough corners on strips under the corners, and then I shall | have the supports as far out as the | For Christmas- Ask Him For One! On Christmas morning, when the curtains are pulled aside and the trep in all its splendor is disclosed to the happy, expectant children, be sure that among their gifts they will fing a Hohner Harmonica. There’s nothing like good music for Christmas; and there’s nothing like a Hohner for good music. Get g Hohner Harmonica today—50¢up- and ask for the Free Instruction Book, ig ange Ba 7 of copies, write - Hohner, Inc., Dept. N York City. vt 162, If you want a musical treat ask to hear Vic. tor Record 19421, by Borrah Minevitch, © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31. The Coil WITHOUT LOSSES The New UNCLE SAM MASTER TUNING COIL Laboratory tests prove’ conclu- sively that it is the only coil worthy of the name low loss. A Few Features of This Wonder- ful Inductance: i—W ound on moulded hard rubber. 2—W ound with genuineA mbas- sador Litz wire. 3—Eliminates adhesives. 4—One hole mount in thin gold plated compen- sating spring contact. FREE—4% your dealer or send “y © addressed stamped envelope for diagrams of circuits in which this coil can be used. UNCLE SAM ELECTRIC CO. 209 East Sixth St., Plainfield, N. J. RRS 8 oS — 100 200.300 400 500 600 Wave Length (Meters) Phase Angle Difference Henigtanes) so > om Arithmetic of Electricity A practical treatise on electrical calculations of all kinds reduced to a series of rules. $1.50 Postpoid. POPULAR SCIENCE MONTHLY 250 Fourth Avenue New York wishes those he cal theate ing sold f have one-te and | amate to as throu! ment; motio for ve to pli or to. the | in cé that nort! blue sout a sear even togr: scrik just sciel labo the of s wid “ \V lem whi arti get tars mo’ JEN

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ity of all Postpaid. Y New York ee _ George Eastman—Greatest Amateur Photographer (Continued from page 35) and that are equal in quality to ae thown in the best theaters. And he can do all this at the cost of a few theater seats. “ ’s a thought, too, that is interest- ing this connection. Our first kodak sold for $25. For several years now we have been able to supply a kodak for one-tenth that amount that gives larger and better pictures - than those first amateur cameras. It is not unreasonable to assume that home movies will go through a somewhat similar develop- ment; that in a few years you can project motion pictures on the walls of your home for very little more than it costs you now to place a still picture in your album or to have one framed. “ ALSO, motion pictures made directly in natural colors are bound to ar- rive sooner or later. Indeed, the amateur movie-maker of a few years hence prob- ably will make the work of the profes- sional of today seem crude and ridiculous. “Tn our research laboratory 120 trained workers—physicists, chemists, and pho- tographic experts—are laboring con- stantly to bring things of this sort to pass. “‘Find the facts,’ the scientists who are working there always have been told, ‘and the practical application will come as a by-product.’ “That is why investigations of no immediate practical value are going on there constantly. People often are amazed when we tell them we haven’t the slightest idea in the world why we are conducting an investigation of one sort or another. They can’t see the use of Such work. As a matter of fact, it hasn’t any use, which is exactly what Faraday, the great father of electricity, said about his first toy motor. ‘But,’ he added, ‘what use is a new-born baby?’ wT BROUGH their investigations into the fundamental principles of color and light, our scientists were able to tell the navy authorities what colors to use in camouflaging ships during the war— that a gray-blue decreased visibility in northern waters, for example, and that a blue-gray brought a similar effect in the south. “Beyond our own needs, too, the re- search laboratory has yielded rich results even in fields not connected with pho- tography. We issue scientific papers de- scribing our experiments and their results just as the college and government scientists do. We maintain in the laboratory the only plant of its kind in the United States for the manufacture of synthetic organic chemicals that find wide use in industry and scientific research. “WHEN the government was training aviators during the war, the prob- lem arose of teaching them to shoot while flying. The infantryman, the artilleryman or the naval gunner could get adequate practice from stationary targets. The aviator, though, required a moving target in the air. It was ob- (Continued on page 142) POPULAR SCIENCE MONTHLY 141 Buy a Studebaker Direct from the Maher” Latest Style Thin FRE | WATCH ¢ CHAIN For a limited time we are offering a beautiful Watch Chain FREE. Write now while offer lasts. STUDEBAKER Co a7 Down! Just $1.00! The balance in easy monthly payments. You get the famous Studebaker, 21 Jewel Watch—Insured for a lifetime—direct from the maker at lowest prices ever named on equal quality. Send at once for FREE Book of advance Watch Styles. 21 Jewel -the Insured Watch Choice of 54 latest, thin model, Art Beauty Cases in yellow gold, green gold or white gold effects; 8 adjustments, including heat, cold, isochron- ism and 5 positions. Direct to you from the factory —the greatest watch value in America today! W M4 Send at once and get a copy of rite f or Style Book! this book—FREE! See the newest, beautiful, advance styles in Studebaker Art Beauty Cases and Dials. Read how you can buy a 21 Jewel Studebaker Insured Watch direct from the maker—save big money—and pay for it while you are using it. Write for our Free Book. It will post you on watch styles and watch values. Send coupon at once. Get Free Chain offer today while it lasts. STUDEBAKER WATCH CO, Dept. E23 South Bend, Indiana Canadian Address: Windsor, Ontario @ Mail Coupon for Free Book j STUDEBAKER WATCH CO. ~ | Dept. E23 _ South Bend, Indiana Please send me your Free Book of Advance Watch | Styles and particulars of your $1.00 down offer. If you live in Canada send your inquiry to our Canadian office: Windsor, Ontario. Address ...... | i City . State | O Check here for Ladies’ Watch Folder. O Check here for Jewelry Folder. j charge. Dept. 130, NVENTORS your ibe YOUR IDEAS Send for our Guide Book, HOW TO GET A PATENT, and Evidence of Invention Blank, sent Free on request. Tells our terms, methods, etc. your invention for our Examina- -—-- ---- ----=-------- ---.------- tion and Instructions without RANDOLPH & Co. i ieleicoee lene see aceire se ecuhwaa ates, Washington, D.C. Send model or sketch and description of © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31.

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George Eastman—Greatest Amateur Photographer (Continued from page 141) viously dangerous to let inexperienced air pilots shoot at balloons or similar objects trailing behind other airplanes. ‘‘Our camera makers designed a special camera which could be affixed to a Lewis gun. When the trigger was pulled, the object that the shooter would have hit if the gun were loaded was photographed. Synchronized stop watches that recorded the time of each shot on the film per- mitted aviators to engage in realistic but safe practice battles in the air. This was an improvement on the foreign camera- guns, which could only take single photo- graphs from which the winner of the duel cou'd not be a3certained.”’ This laboratory, of course, is only a single unit in the immense enterprise that has grown from the experiments that young Eastman started .in his little Rochester laboratory 47 years ago. In Rochester alone more than 10,000 people help carry on the work of supplying the world with the cameras, lenses, plates, film rolls, photographic paper and chemicals and motion-picture films it requires. (oe plant—Kodak Park, where film, paper, and chemicals are made— occupies 230 acres, and contains 119 build- ings, from which issue, among other things, 150,000 miles of motion-picture film in a year in addition to the kodak film and the film used for professional por- traiture and for X-ray work. Here, Mr. Eastman told me, three tons of silver, one-twelfth of all that is mined in the United States, are used every week in the sensitizing of film and photographic papers. A _ single refrigerating plant there, used for the purpose of maintaining the film rooms at a constant temperature of 70 degrees, yields the equivalent of 4000 tons of ice every day—sufficient for the needs of a city of 200,000 population. The water supply system maintained at Lake Ontario, six miles away, is large enough to serve a city equally large. The electric power plant furnishes 15,000 horsepower to run 4300 motors and light 40,000 lamps. Five million pounds of cot- | ton are used here in a year in making film, | while into the kodaks that are made in the camera works in the city go every year 480,000 pounds of aluminum, 2,000,000 pounds of brass, 1,400,000 pounds of steel, 2,000,000 square feet of leather, and 1,500,000 board feet of lumber. Chemicals and other materials that ordinarily are used only in minute quantities -are handled here in carload lots. Such figures are staggering, especially when you recall that the products they shape all sprang from the experiments of a single young man, who still remains the | active head and guide of the vast enter- prise he founded.

tor though to the majority of those who use his products George Eastman is a name only, here he is a definite, dominating personality, whose hand is constantly discernible in even the re- motest ends of the great business that bears his name. Certainly he is responsible (Continued on page 143)

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rY, IMs POPULAR SCIENCE MONTHLY January, 1925 143 ——. | a ii AUC stn aeRO LE, George Eastman—Greatest DG Amateur Photographer MURDOCK NEUTRODYNE or be (Continued from page 142) ; for the remarkable spirit that pervades | ante, his organization—a spirit of pride and City, Na loyalty that is to be noted from top to ~onla bottom. People stay with the Eastman ? organization. A half-dozen with whom EE I talked had been there a quarter- eT know, or more. te gs there is an explanation of that ding sto ‘it in the cleanly, sanitary, more than 74 oe spirit in t : : tre eet attractive surroundings in which even the UAE S | most laborious work of the organization beg, | jg done; in the extraordinary care to safe- guard the physical health of the workers. Perhaps there is another explanation | in the system of rewards for mechanical nial” _ workers who suggest improvements in the leant | machinery and processes. Perhaps the Poome-j amazing scope of the welfare work carried bi on among the workers of the Eastman on bot | | organization may have something to do Los Angela with it. Perhaps it is in a sense the re- B flection of the spirit of the man who built and endowed the $9,000,000 Eastman Theater and Eastman School of Music in Rochester; who gave $50,000,000 to hos- pitals and educational institutions as “Mr. Smith,” shielding his real identity, until the law compelled the beneficiaries to | make known the name of the donor. FIT 4 wee ui Bmore, Icense: 4 E | ¢ 3 my sevens " ee is your hobby now, Mr. 'N UTRODYN | Eastman?” I asked him after he NNOUNC ng-~ ie U.S Pat: | had traced the progress of the Eastman Omer Patents Pencing organization from its humble beginning to its present position as one of the best- NOTICE The new Murdock 5-tube known concerns in the world. ; a ; éé 7 “I am an amateur photographer,” he Fg tovwn gor! Neutrodyne with “built-in” Loud | replied instantly. ‘‘ For years I made still Murdock Pro- ducts write _ ieuifuly tee | Speaker and “B” battery compart- pictures; now I make movies. This summer I exposed several thousand feet trated booklets ‘ of film on a trip to Alaska.” giving complete | ment—backed by 20 years experi- | An amateur photographer! Th all Murdock ’ ° . who was an hia i there ny = wh ence in making fine Radio Products, _amateurs! The man whose genius put | into the hands of all photographers—from WM. J. MURDOCK COMPANY, 430 Washington Ave., Chelsea, Mass. ‘the children who snap their first tiny | kodaks to the men and women whose skill oT Sid 'has won them international fame—the tools with which to practise the art! @ CHICAGO . Second Prize cogtomaiingeag RADIO PRODUCTS | “Three boy scouts had been spending | - using at hours trying to photograph birds and | Sales Offices: New York, Chicago, San Francisco, Washington, D. C. eee : es A ¢ raking 30 | animals in the marshes. The article on | stem &|‘Wiy Animals Understand) Me’ ‘was | Standard since 1904 eal eagerly read and Girard’s suggestions | gents and opened up a new field of opportunity for ik. Write them. BURN YOUR NAME ON TOOLS “A class of boys raised $20, and with wires the specifications given by Grant Hector, | ARKOGRAF built a ‘Coast to Coast Radio Set’ for a A little crippled invalid girl. | from phot, Write tnd aie, areas “The magazine was then passed on to | | ‘lectticity like writin jan paper with Pe eight pupils who read assigned articles, | B3.b0, prepaid anywhere, ‘Interest. and each gave a three-minute oral report | Shot Guns Breech Loading $4.50 —) j —$—$____ U.S. Cal. 45 B. L. Rifles. Bar- rels cut to 22 inch length. Rebored ing descriptive circulars free. Write smooth for bird shot. to- ents wanted, Bird shot Cartridges for these guns.$3.00 hundred to the Better Engli aR ~~ Sorcpeninemenacened ee eS fe Seagen Cio. | Ball Cartridges $3.00 hundred ; ° _—“__C_CSslsloass— eee )sC«dS@?SCSOC#S3{Baalll Carrtridgees_------------------ ¥ nee during the month the class writes | - © HonEYCoMB COILS Best Gun in the World for the Price . critical Paper on the advertising. The Uni lall Leather Scabbard to hold this gun_..--...-- $,138 4 When the November copy arrives the inductance. Back and |) Krag Sporting Wifles--2-2722222220IIII2-§14.00 aver number will go to the Nevada Co, Ogee mesesees. 1 Ca Gs comes... --..-...8 ining Camp. en c for_ Super Jtility B for bait, lunches, etc. Parcel Het., R. F. and Honey- bahee pce gy lege Se 40c a a and Send for Catalog omplete Catalog. 1627-FB North 10th St. 97 Chas. A. Branston, Inc, W. STOKES KIRK, puitapecenta. pa: l Dept. 9, 815 Main St. Buffalo, N. Y. “Was the current number worth the money? I’ll say it was.”—T. N. KRuUGER, Mexia, Tex. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31.

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POPULAR SCIENCE MONTHLY Nothing Likea BUESCHER True-Tone Saxophone Of Your Own —To play the newest hits. —To play with piano accompaniment. —To play in orchestras. . —To play in bands. —To put life in every party. —To make new friends. —To win a welcome everywhere. —To make you a leader in church, lodge, fraternity or school circles. And it is all so easy. Easy to Play Easy to Pay The Saxophone is so perfected and sim- plified that it is the easiest of all musi- cal instruments to Buescher Saxophone Book FREE learn. With the aid of the first three lessons, which are sent free“(upon re- quest) with each new saxophone,the scale can be mas- tered in one hour; in a few weeks you can be playing pop- ular music. Within Every music lover should send for a copy of this in- teresting book on the his- tory and development of the Saxophone. It tells which Saxophone takes violin, cello and bass parts, and many other 90 days you can things you would like to take your place in know. Also illustrates first a_ band if you de- lesson. Send coupon for = your free copy. Try It In Your Own Home We will send you any Buescher! Saxophone, Cornet Trumpet, Trombone or other orchestra Instrument you may select. You can try it six days in your own home without obligation. Easy terms of payment arranged if desired. Mention the instrument interested in and we shall mail you our complete catalog—free. Buescher Band Instrument Co. Everything in Band and Orchestra Instruments. 385 Buescher BIk., Elkhart, Ind. cotati ienedione gama Buescher Band Instrument Co. 385 Buescher Block, Elkhart, Ind. l Gentlemen: - I am interested in the instrument checked below: y § Sgrophone_-. Cornet... Trombone... Trumpet--- (Mention any other instrument interested in) l | Name... -..--------------. -------------------- | 1 Ce ee ee ee I Town... a When Men Race with Death (Continued from page 37) Macready finally straightened it out, and with its tiny 40-horsepower motor splut- tering away, got it up about 350 feet and flew it mile after mile, then brought it down to a perfect landing. The astonishing strides made in avia- tion since the Wright brothers first coaxed their plane to hop before an incredulous audience, more than a decade ago, was emphasized by what followed Macready’s daring flight. 74 ABOLy had Macready descended when five youths took the air, one after another, in machines of their own manufacture. The first was a spick-and- span little monoplane, painted a bright yellow, with a motorcycle engine as its power plant, piloted by J. M. Johnson, of Dayton. This little ship hopped off with astonishing agility, climbed a thousand feet, and was off in the distance. Right after the homemade monoplane came the most popular machine of all the 350 at the races—dubbed the ‘Flying Bathtub,” because that’s what it looks like. It was piloted by its young builder, E. Dormoy, of Dayton, Ohio, very tense and very proud, as well he might have been, for the machine fluttered unpleas- antly, though it did fly with complete abandon. Three others followed in trim little ships. The five participated in a thrilling 25- mile race, won by Johnson with an aver- age speed of 64.07 miles an hour. A second light-plane race further demonstrated that there is a great future in air flivvers. It was an efficiency race. H. C. Mummert of Garden City, N. Y., won it, flying over a 50-mile course at an average speed of 38.24 miles an hour. He didn’t go very fast, true; but he flew economically. His two-cylinder motor- cycle engine consumed little more than a gallon of gasoline. His gasoline tank had 4.0000 37% Long-Eakins Co, a capacity of 14 gallons, so he could have | flown from New York to Chicago. Now, American aviation has not yet developed either airplanes or motors satisfactory enough to make these light planes a commercial proposition. French and English builders are a bit ahead of us in this. But the time will come when Americans will have developed a light plane suitable for general flying, and cheap enough to attract the average automobile purchaser. HE public, if it knew all the facts about airplane racing, would want to see it continued year after year, until the United States has won for itself an undis- puted leadership in the world of aeronau- tics. That is by no means an impossibil- ity, as a few such facts as these will show: American planes have flown more than 268 miles an hour. They have stayed in the air 30 hours, climbed 10,000 feet in 10 minutes, carried bombs weighing 4000 pounds, reached an altitude of 35,000 feet, crossed the Atlantic, made a non-stop flight of 2700 miles, crossed the continent from daylight to dusk, sunk battleships 70 miles at sea, and have flown around the world. What nation can match that record? How Good The Bristles Fee| The first thing you notice about a WHITING - ADAMS BRUSH is how good the bristles feel. How strong and _ springy they are! Then you notice what a clean- cut, _ perfectly-bal- anced, and “usable” article the whole brush is. Ask your dealer to show you one. WHITING -ADAMS BRUSHES AYS 11 for = Illustrated pre Literatur a Gs Making a Brush G to Last a Lifetime is a Lifetime Job JOHN L. WHITING-J. J. ADAMS CO, Boston, U.S.A. Brush Manufacturers for Over 116 Years and the Largest in the World Jacob Gordon’s Record Making and Selling POPCORN CRISPETTES Gordon was driving a delj wagon. Ira Shook, Flint,t in $365.75 in 1 day. Mrs. Lane, ; Pa., 8000 packages in one day, eee | We'll Start You in Business Furnish secret formulas, raw material, and equi ment. Small capital, no experience needed. B Business of Your Own! No limit to sale of Crisp. pettes. Everybody likes this delicious confection, Write for facts about a business that will make yoo independent. Startin your own town. PROFIT $1,000 A MONTH EASILY POSSIBLE Send for book of facts. Contains letters from others shows their places of business, tells how and when to start, and allinformation needed. Free. Writenow. 147 High St. Springfield, 0, , “Re/ieve . your ~ trouble zone ~ THE NOSE THROAT ak 4 a LUDEN Scotetorts Have You AN INVENTION? If}so the WORLD PROGRESS will show you how to Protect and Profit From Your Ideas Sample copy free. One year’s subscription 40s Send for free book, “WHAT TO INVENT” containing Suggestions to Inventors as t0 Inventions Needed. We invite manufacturers to address us regarding inventions they want WORLD PROGRESS PUB. CO., INC. Room 202 Victor Bidg. Washington, D.C a =% sent. Write for phen, Ba presses, type, fa& etc. THEPRESSCO., F-33, Meriden, Comm ill, SA ( This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31. | aa of — -—- yy = -—. O85 ooh bee — v Lam >) Ss wa nRerg As Re Meter o ct ao & ware csc 2ue wo a

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January, 1925

[== A Thrilling Search (Continued from page 40) ing area, the expedition here divided into two halves, one working east of the river and the other moving through the regions to the west. In this portion of the journey the fallacy of existing maps was fully demonstrated. From here on there was no lack of thrills. Ice cakes were found to have a habit of breaking off and making plunges that kept the navigator on constant lookout for trouble. HE boulder belt was another place of navigation under difficulties. Over an area several miles in width the whole channel of the river was studded by boulders large and small. Through these the canoes had to be lowered by means of tail ropes, handled by the voyagers from uncertain footing on the bank, on the slippery tops of the boulders them- selves, or in the midst of the current. The travelers reached the Colville River after nearly three weeks of such progress down the side streams. The Col- ville was found to be 300 or 400 yards in width, with swift current. Up and down this Colville and its various tributary streams, the surveyors and geologists worked, making maps, gathering speci- mens of rocks and making various tech- nical measurements and observations. Toward the latter part of July both parties began searching for passes » through which to advance to other north- flowing drainage entering the Arctic Ocean. Location of a route was followed ' by one of the greatest portages of the ex- pedition, involving the transport of boats, supplies, and general outfits for a distance of eight or 10 miles across hilly country. This brought the voyagers to canoeing water on the Chipp River. In its lower portion the Chipp River splits into two branches. In following these streams the expedition split into two parties for sur- ‘ veying purposes. ay SEN the expedition was reunited on the south coast of the Arctic Ocean, it remained for the voyagers to make their way to Point Barrow, the northernmost spot on the American continent. This involved a journey of 150 miles westward —a trip undertaken and negotiated in the well-battered but seaworthy canoes. This portion of the trip produced its thrill in the form of enforced isolation on a bleak sandbar for a period of 36 hours. The experience came during a severe windstorm. The force of the gale was such that the canoeists were unable toreach the mainland and unable to continue their progress. A day and a half of imprisonment on this bleak spot left lasting impressions. Ice pursued the expedition to the last. After considerable travel in the open sea, the adventurers were forced at last inside a fringe of sand reefs to escape the vast ice-fields along the coast. Even within sight of its goal the party encountered ice troubles of proportions that made it necessary to cut across the narrow sand spit that connects Barrow with the main- land of Alaska. Barrow was reached August 22. From this point vessel trans- portation to Nome, in southern Alaska, was obtained.

POPULAR SCIENCE MONTHLY

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a “Experience is the Vital Factor in Excellence” GhHhoMPson RADIO i eae THOMPSON COMPANY is the only organization that has been manufactur- ing radio apparatus exclusively for fifteen years. During this time its research labo- ratories have perfected developments which have contributed largely to the advancement of the radio industry. This wide experience, now available in the Thompson apparatus, means A critical investigation of each model will disclose outstanding features of yenuine effect, in artistic appearance, naturalness of tone, simplicity of opera- tion. Radio in the home broadens the scope of human happiness. Every day the broadcast program carries something for every member of the family.

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Kr MURD (Fd GzarkA MU SIO PFANSTIEHL PHOENIX ANDREWS MALONE LEMON AUDIOLA GATES ae ONY ODELL FERRY PEERLESS DUCKS DELUXE SAAL AND MANY OTHERS H BE 3% Pee a ULTREDXNE MICHIGAN POPULAR SCIENCE MONTHLY Jw their lead Thirty-four nationally famous makers of quality sets use Thordar- sons as standard equipment. Thordarson produces more transformers for more leading set builders than all competitors combined. What better evidence is there that Thordarsons are superior? And why shouldn’t they be? They are meade and un- conditionally guaranteed by the world’s oldest and largest exclusive manufacturers of transformers — transformer specialists since 1895! : Follow the lead of the leaders—build or replace with Thordarsons or buy Thordarson-equipped sets. All stores can now supply you. Audio Frequency types in three ratios: 2-1, $5; 344-1, $4; 6-1, $4.50. Power Amplifying (for push- pull circuits), pair $13. Write for latest bulletins—free! New York City, Sept. 25, 1924. ge + Electric Mfg. Co. 0 W. Huron St., Chicago. yn transformers which you supplied to equip the Radio on the schooner Bowdoin stood the extreme temperature of the Arctic without the slightest mishap. These transformers are in exactly the same con- dition today as they were the day they were installed, May, 1923. : Sincerely yaure. (Signed) Yuutd 13 W. yap HORDARSO} AMPLIFYIN UPRANSFORMERS Standard on the majority of quality sets Unconditionally Guaranteed by THORDARSON, ELECTRIC MANUFACTURING CO. e 1895 WORLDS OLDEST AND LARGEST EXCLUSIVE TRANSFORMER MAKERS Chicago, U.S.A. ocK and coal-saver. GUARANTEED Burns Smoke Keep your home— Comfortably and use less coal in doing it EDUCE your coal-bills at least 20% keep your home cozy and warm taching the inexpensive CROWN Fuel Saver to your heating plant. 15,000 homes and business places are benefit- ing by the use of this marvelous heat-producer The CROWN is guaranteed to make at least a 20% fuel-saving or its small purchase price will be refunded immediately. “THE CROWN FUEL SAVER HEAT FROM PERFECT. / COMBUSTION CAPE:X VERNERDAL>) Warm and y at- More than It Brings ’Em In! Get more stations—greater range—bigger vol- ume—finer eee Setseconaene. Lasts forever. The one wt in tuning. Ratio 12 to 1. ick applied to to any ‘shaft. For sale by all Radio alers. If unable to ob- tain from tert enclose $2.60 for w-wh a finish, or $3.50 for De Luxe satin finished gold. January, 1925 The Show of a Lifetime (Continued from page 44) number of solar and lunar eclipses pos- sible in any one year varies. There may be as many as seven eclipses, of which five may be solar and two lunar, or as few as two, both of which must be solar. It is an interesting fact also that eclipses repeat themselves at nearly the same time and place at intervals of 658514 days, or a little more than 18 years. This period is called the “Saros.” It was known and understood by the ancient Chaldeans, and was used by them to foretell eclipses. Solar eclipses are of three kinds—total, in which the sun is entirely obscured; annular, or ring, in which all the sun is obscured except a distinct ring around the rim, and partial, in which only part of the sun is obscured. The first two types always are accompanied by the third type. AND now, in imagination, let us take our position on the morning of Janu- ary 24, at about nine o’clock, not more than 30 or 40 miles from the center line of totality, on high ground if possible. Through our dark glasses we watch the dazzling face of the sun. At the ap- pointed time one edge of the sun becomes slightly flattened, an appearance that be- comes momentarily more pronounced. During the hour or so that precedes the total disappearance, other effects are ob- served. The partially exposed disk of the sun may take on a ruddy or reddish hue, the temperature will fall somewhat, accompanied by increasing wind; clouds will collect and lower. By nine o’clock, totality is approaching fast. Gusts of wind arise. Strange color effects appear. Jupiter, Mercury, and Venus, and some of the brighter stars are seen close by the sun. Weird streamers of light reach out from the sun, and the mysterious ‘‘shadow bands” may be vis- ible. If the sunlight is falling on a plain white or light colored surface near you, watch it closely just before totality. On it you may see the shadow bands—sin- gular, wavy lines of light and shade, traveling along with a variable, undula- tory motion. The exact nature of these phenomena are not yet understood. At the instant before totality you will see the moon’s thunder-black shadow sweeping across the country from the northwest with appalling speed. If at this moment, you glance at the swiftly disap- pearing rim of the sun, you may glimpse ‘“‘Bailey’s Beads’’—shapeless spots of bright light, fringing the extreme edge of the last rim of the sun. These are caused by the last visible rays of sunlight shining through the canyons and chasms of the mountains of the moon. j= id ‘ ki we a Salar array Tym nee ~ SEVEN ae RicEn ma wets pe T THE instant of totality the incom- parable corona of the sun flashes into view; that glorious halo, pearly, soft, unearthly in color, stretching at times millions of miles into space, and to be seen only during the few seconds of The CROWN (see _ illustration) provides an qunitias supply of pre-heated air which burns the 7-Tube Super-Heterodyne gases at are ordinarily wasted in the form of caaiee iving a tremendous increase in heat. for $97.50 The CROWN insures steady heat and plenty of it Receive the parts complete to assemble ¥. on the minimum of coal; less trips to fire the furnace; and a real money-saving over a period of years. Write today for full details and a free booklet, **Making the Coal Bill Look Like 30 Cents.’ C. F. S.Co., 11 N. 10th St., Distributors Wanted—Write for interesting proposition. own set. Coast to coast on an 18-inch Loop, ‘Assemble tt thie 7. 7-tube Microdyne Super-heterodyne on a7x18 in. panel in three hours. Parts complete, including drilled and d panels, condensers, sockets ts, Se necting plugs, cables, etc., with draw’ ms and instructions. ‘Price of cabinet—to fitton application. if _ your radio dealer cannot supply parts for complete o Bet, send check or money order for $97. 50 and name ¢ of your deale er. APEX ELECTRIC MFG. C 0., Dept, 103 1410 W . S9th Street, CHICAGO Richmond, Ind. totality. Then the blue-black shadow departs as swiftly and as silently as it came. You may watch in reverse order the great phenomena. There won’t be another chance to see a total solar eclipse in the United States until 1945. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See Page 31.

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er GS ww vill his Lp- ose of of sed ing the ym- nto oft, nes _ be of low he der see ates January, 1925 [ Crime Mysteries Bared (Continued from page 52) to beat a prisoner until he confessed. With the aid of the Locard microscope the same effect now is obtained by beating his clothes. In Paris recently a man was found dead in a deserted spot. He had been killed by a blow on the head, and all about the place where the body was discovered were evidences of a terrific struggle. A few days after the body was found the police arrested a man who, they ascertained, was an enemy of the dead man. The prisoner stoutly denied his guilt, and the police were unable to shake his story. ib Yigrver! Doctor Locard took thesuspect’s coat, placed it in a sack, and beat it thoroughly. This he did also with the coat of the dead man. The twosamples of dust particles collected by this method were found to correspond exactly when photo- graphed by the microscopic camera. These photographs, introduced in court, went a long way toward convicting the pris- oner. An even more dramatic use of the mi- croscopic camera sent to the guillotine a young Lyons bank clerk for the murder of his sweetheart. This young woman was found strangled in her apartment. The bank clerk, arrested, established what seemed to be a complete alibi. Doctor Locard examined the body of : the murdered girl, and discovered several small scratches on her neck, made by the finger nails of the murderer as he choked her. Next he obtained a specimen of dirt from beneath the prisoner’s fingernails. When this dirt speck was photographed under the microscope, exceedingly minute bits of torn flesh were disclosed. Also, there were blood corpuscles. Most im- portant of all, though, there were small crystals, which Doctor Locard estab- lished as those of the face powder habitu- ally used by the murdered girl. In a recent murder case, the micro- scopic camera in the hands of the police supplied virtually the only evidence against a prisoner—sufficient evidence to convict him. This was a stabbing case, and the police had little to connect the prisoner with it except a possible “‘ motive” —the death of the murdered man was to his advantage. To offset this, the suspect offered a complete alibi. HEN all other efforts failed, Doctor Locard suggested that the hands of the prisoner be photographed under the microscope. When the plate was de- veloped, lodged in the pores of the fingers were found traces of blood from the victim’s body. The prisoner had washed his hands, but, enlarged 50,000 times, the tips of his fingers yielded the unmistak- able evidence that convicted him. In the police museum at Lyons, Doctor Locard has assembled amazing exhibits of scientific crime detection. Here are remarkable finger-prints; one enlarged 16,000 times, the pores of which appear as large as a fifty-cent piece; another print which recorded itself through a cloth glove, and still another possessing 116 characteristics distinguishing the hand of a murderer who stabbed his victim 32 times for the sum of about two cents! POPULAR SCIENCE MONTHLY ‘They Improve Reception | Electrad Audiohm Eliminates Trans- former Distortion Also stops audio-amplifier whistles or howls. Assures a more bal- anced reception of all notes of music and voice. Makes repro- duction free of blur and falsetto exaggeration. You mount the Audiohm across the secondary of your audio transformer. Can be attached in a minute, and without solder. Easy to operate as setting your watch. Fits any transformer—and lasts for years. Buy an Audiohm today and get fine reception. We guarantee re- sults. Price only $1.50. Electrad Variohm Gives That Last Hair-breadth Tuning Permits you to get stations you never heard before. Clears up those stations you have heard only indistinctly. Affords that super- fine tuning which every discrim- inating fan has long been seeking. The Variohm is a good, vari- able grid leak that works with fine precision. Allows much finer variations of adjustment from 4 to 6 megohms, and coarser ad- justment from 2 to 20 megohms. Install a Variohm in your set today —and get the fullest power, clarity and distance from it. Guaranteed. Price $1.25 unmounted, $1.50 mounted. Electrad Audiohms and Variohms are on sale at most good radio stores. © If your dealer doesn’t carry them, order direct, and give his name. ELECT RAD. 428 Broadway, New York City The Midget “‘Five-in-One’’ Slide Rule isa bination M hei Polymet- ric, Log-Log. Binary, Add and Sub- tract Slide Rule, It will instantly add, subtract, multiply and divide any com- bination of whole numbers, fractions, mixed numbers and decimals. Gives every root and power. also Logs, Sines and Tangents. Made of aluminum with scales on white celluloid. Size 4 in. Ap- (Patented 1-17-' Clearze:/ Your Skin Can Be Quickly Cleared of Pimples, Blackheads, Acne Eruptions on the face or body, Barbers Itch, Eczema, Enlarged Pores and Oily or Shiny Skin. Write today for my FREE SOOULET, FREE “‘A CLEAR-TONE Lee | | how cured myself after being afflicted 5 years. E.S.GIVENS, 153 Chemical Bldg., Kansas City,Mo. $15 aDay We want men and women everywhere as local representatives to demonstrate’ and take orders for Comer Topcoats and Raincoats. New offerenables you to earn $100 a week and a Dodge Tour- ing Car. No capital, experience or training needed. Write for details. 18) THE COMER MBG. CO. ‘ Dept. 0-49, Dayton, Ohio \ ae TOURING f CAR - FREE © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31. How to Build CLTRADYNE MODEL L-2 32 page illustrated book with de- ° tailed instructions on drilling, wiring, assembling and operating Model L-2 Ultradyne Receiver. Latest authentic edition by R. E. Lacault, A.M.I.R.E., inventor of the Ultradyne, the most selective receiver known. Write for descriptive circular. PHENIX RADIO CORP. 5-7-9 Beekman St., N. ¥. q a

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148 Oversize focking nots, slotted ‘for screw driver, eliminating use of pliers to tighten Sq] Marge taminated silicon steel. 4 sshell type core. in general the larger the core [ii the better the transformer — [im Federal No. 65 weighs exactly 14 pounds — guaranteeing a fonal quality and modulation \ pre-eminent among trans formers. “Master of Every Note in the Or- chestral Range” is the proven claim of the Federal No. 65 Audio Fre- quency Transformer! Volume without distortion is the basis for the beauty of Federal Tone. From its oversize locking nuts to its heavy brass mounting feet the Federal POPULAR SCIENCE MONTHLY Primary and secondary fed thru hollow screws and dip-soldered making complete protection against breakage or shorts. Only highest grade genuine var- nished cambric tubing used. Black enameled shield, com- pletely surrounding windjngs Heavy nickel plated brass moun- ting feet—2 screw slots and 2 screw holes for mounting. No. 65 Transformer incorporates the same engineering skill that has made Federal the recognized leader in electrical communication apparatus since 1890. Insist upon Federal parts for your “‘pet’’ hook-up. There are over 130 stand- ard parts bearing the Federal iron-clad performance guarantee. FEDERAL TELEPHONE AND TELEGRAPH Co. Buffalo, N. Y. 1S] Boston Chicago New York San Francisco Philadelphia : : . Bridgeburg Pittsburgh Standard RA D | O Products Canada January, 1925 An Ideal ’Xmas Gift! ‘Vacufarm, On the Instrument Board of Your Car Blows Horn when Gas is Low. Tells exact amount in tank. Vacuum Indicator warns of trouble in advance. At your dealers or by Parcel Post, prepaid with complete instructions on receipt of price— $8.90. Installed in 20 minutes. oney back in 30 days for any reason. THE SMITH MOTOR EQUIPMENT CO. 1955 West 77th St. Cleveland, Ohio c .. for Ais Christmas HE Simore’ Screwdriver or Com- bination Knife and Screwdriver make an ideal gift for the man or boy. Model No. 11 has three screwdriver blades; No. 12 has a fine knife blade and two screwdriver blades—both unusually useful and beautiful tools—blued steel handles—best steel in blades. They look the part of a real gift for the boy or man who likes tools—try one on a friend of yours and watch him register joy. He'll do it, too. Model No. 11 only $1.50 and No. 12 for $1.80. Send money order or your check and we will mail post prepaid at once. Each tool guaranteed—your money refunded if not satisfactory. Dealers ave requested to write for our new price list on these tools and the Simore Automatic Trysquare. Boost Simore tools for Christmas. THE SIMON & SKIDMORE MFG. CO. Dept. 5-1 Santa Ana, California How I Lead the Largest Gym (Continued from page 75) Here’s an extract from one I received this morning. It comes from a young woman in western Pennsylvania. ““My mother and I want to thank you for solving one of our greatest problems —my father. He retired from business two years ago, and, until your morning exercises started to come in over the radio, he had been the most miserable man in the world. He didn’t know what to do with his time, and used just to sit around in my mother’s way. Now, though, he’s up at 6.30 every day, so that he won’t miss any part of your program, and he insists that mother and I do the exercises too. What you had to say about the benefit of fresh air and exercise impressed him so much that he now goes out for long walks, works in the garden, or fixes things around the house. I’m sure you’ve added to his life, and you’ve certainly kept my mother from going crazy with him.” One letter like that more than repays me for all the trouble it has been to organize and conduct the class—and I’ve had 50,000 of them. ANN INGENIOUS young man in Ver- mont wrote me that he had attached his alarm clock to the switch of his radio set, so that the set is turned on every morning in time for him to hear our alarm from the studio. Hundreds and hundreds of families of from four to 12 members have formed the habit of doing the exercises together. Here’s part of a letter in that regard from a young woman in New York City: “I’m one of those bobbed-haired ste- nographers that I heard you telling the people to make get up and do the exer- cises. I used to lie in bed and laugh when I heard the others taking their daily ‘physical torture.’ One morning, though, I got up to watch them, and ever since I’ve been helping them loosen the plaster on the ceilings. You’d enjoy watching us. There’s pop, mother, my sister, my brother, and myself, and the baby, who is two, sits on the floor and laughs at us. Please, though, don’t tell any more jokes while we’re doing the ‘front leaning rest.’ The other morning I laughed so hard that I couldn’t hold myself up, and almost broke my nose and spoiled my beauty.”’ gest anybody who sees this be fright- ened from becoming one of my early birds by that young lady’s words, let me hasten to assure you that she, too, was telling a little joke. There really isn’t any danger of broken noses, spoiled beauty or any similar casualties in the sort of gym- nastics that we do. The contrary is true. It will add to your beauty if you’re a woman, and to your health, strength and efficiency if you’re a man, to take from 15 to 20 minutes’ exercise every morning. Tune in on WOR some morning if you don’t live so far West that our seven o’clock will be the middle of the night for you, and I’]l tell you more about it. Or, as I suggested above, try the exer- cises pictured here for a few mornings. You’ll find it the most profitable 15 or 20 minutes you ever spent. For that I have the word of 50,000 people. © This seal on a raJi« or tool advertisement signifies the approval of the INSTITUTE OF STANDAP.DS, See page 31.

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ved ing you 2Ms less ing the ible hat sit ow, hat am, the say cise 2OeS Jen, I’m u’ve bing ays 1 to I’ve Ver- ched adio very arm s of 1 the ther. from ste- - the 2xer- vhen laily ugh, since aster g us. my ho is t us. iokes rest.’ that most ” ight- 2arly t me was ; any ty or sy m- true. re a and m 15 ning. you even light it it. exer- ings. or 20 have January, 1925 POPULAR SCIENCE MONTHLY 149 Here Are Correct Answers to Questions on Page 73 1. It is made so that the top part of it is much lighter than the bottom part. Usually there are also ballast tanks to make the bottom part of the submarine still heavier. 2. It rests between beats. The actual contraction of the heart muscle takes only about a tenth of a second. Then it can rest until the next contraction begins, usually about eight-tenths of a second later. 3. Because neither of them contains any nerves. Pain is caused only when a nerve is injured. 4, Eighty-seven are now known. 5. Snow is made up of a vast multitude of very tiny crystals. Each shiny face of each of these crystals reflects light, just as the cut facets of a diamond do. these reflections from the millions of tiny crystal mirrors combine to make the glistening beauty of snow. 6. It is the system of weights and measures devised by the French Govern- ment in 1795 as one result of the French Revolution. The fundamental unit of the system is the meter, a length that originally was intended to be one forty- millionth of the circumference of the earth. It happened, however, that the figure used for the size of the earth was wrong. One standard meter equals about = feet three inches; 3.2808 feet, tobe exact. 7. Because the wire keeps the stream of electrons together so that few of them get lost. The electricity goes farther in a wire, just as you can pump a stream of water farther inside a pipe than you can if you merely shoot it into the air. 8. The most distant heavenly object now known is a cluster of very faint stars, far too faint to be seen by the naked eye. It is known only by its catalogue num- ber, N. G. C. 7006. Its distance is about 220,000 light-years. In miles this equals the almost inconceivable figure of 1,293,572,675,000,000,000 miles. 9. It is not the smoothness of the ice that makes it slippery so that you can skate on it; it is something quite different. Pressure melts ice a little. When your skate rests on the ice, the weight of your body melts the ice so that there is a very thin’ film of water underneath your skate. You really slide along on this water film. 10. Because it is too heavy. The heaviest known rocks weigh less than 200 pounds to the cubic foot. The earth as a whole weighs 345 pounds to the cubic foot. There must be, therefore, a heavy central core of some kind; many geolo- gists think that it is a core of iron. 11. The heat fuses some of the ashes so that the particles of them stick together into solid lumps. Some kinds of coal leave an ash which is more fusible than that of other kinds. So different kinds of coal vary in the amount of trouble they cause with clinkers. 12. When a piece of iron is treated in certain ways it acquires some unusual properties. It attracts other pieces of iron; one end of it tends to point toward the north as the compass needle does; and soon. Wesay that it is a magnet. Super-Ducon A Major Radio Invention A. C. Type $47.50 D. C. Type $30.00 No more B batteries! The Super-Ducon is one of the most important and valuable radio inventions of the year. It brings many advantages to the set owners. Upkeep expenses are cut. No more of the expense and fuss of installing ‘‘B’’ batteries. No more poor reception due to weak batteries, but 100% performance all the time! Ask your dealer for a copy of the 16-page Super-Ducon Booklet. Dubilier CONDENSER AND RADIO CORPORATION New Hexagon Shaft Insures Condenser Perfection To eliminate fanning, the rotor blades are stamped with a hexagon hole and held rigidly on hexagon shaft. Found in types 3 (plain) and 4 (all - vernier), Celoron End Plates; types 5 @) (plain) and 6 (all-ver- nier), Metal End Plates. 100% GUARANTEED Write for Folder U. S. TOOL COMPANY, INC. 127 Mechanic St., Mfrs. of Special Tools, Dies, Jigs, Automatic Machinery and Sub Presses. Newark, N. J. Home Protection with an ASTRA Automatic will cost little Nearly every man wants a gun in the house—he feels better able to protect his family. We are able to offer these Genuine Astra guns at special prices because we bought be- fore recent tariff raises became effective. Really fine guns, beautifully finished, hard hitting. Use standard ammu- nition. Order direct ‘rom U.S. importers. $7. 75 25 cal., 7 shot ASTRA, C.0.Q. Automatic, 8.95 25 Cal., 7 shot ASTRA, Automatic 9.95 25 cal, 7 shot ASTRA,, triple safety. 10.95 32 cal., 10 shot ASTRA, extra magazine, $16.95 “The Plainsman” Revolver f 32-20 and 38 long cali- bre; except for difference : in calibre, the same gun in weight, size and appear- ance. A regular he-gun, best blued steel, fully guaranteed, ry cree revolver ammunition. Only 16.9 Write for firearms catalogue. We guare antee perfect workmanship and material; every gun brand new; of drop forged steel throughout. Before buying any gun insist on this guarantee. ho money unless you wish. Pay postman on delivery plus postage. Money cheerfully refunded if not fully satisfied. ACT NOW oe Bet these SPECIA', LOW PRICES, WRITE TOD CALIFORNIA a COMPANY Dept. 11 747 Warehouse St., Los Angeles, Cal. © This seal ona radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 31. Sy ee ae APN —

Page 118

POPULAR SCIENCE MONTHLY January, 1925

$$ < ui en a a Tube Set—1925 Model (Continued from page 81)

What will you be doing one year from today?

Three hundred and sixty-five days from now—what? Will you still be struggling along in the same old job at the same old salary—worried about the future—never quite able to make both ends meet—standing still while other men go ahead? One year from today will you still be putting off your start toward success—thrilled with ambition one moment and then cold the next—delaying, wait- ing, fiddling away the precious hours that will never come again? Don’t do it, man—don’t do it. There is no greater tragedy in the world than that of a man who stays in the rut all his life, when with just a little effort he could bring large success within his grasp. Make up your mind today that you’re going to train yourself to do some one thing well. Choose the work you like best in the list below, mark an X beside it, mail the coupon to Scranton, and without cost or obligation, at least get the full story of what the I. C. S. can do for you. ~ INTERNATIONAL CORRESPONDENCE SCHOOLS — Box 7632-D, Seranton, Penna. Wyhest cost or obligation on my part, please tell me how I can qualify for the Y en or in the subject before which I have marked an X BUSINESS TRAINING COURSES Business Management Salesmanship Industrial Management wey Personnel Organization Be Traffic Management Show Card Lettering Business Law Stenography and i Typing Banking and Banking Law Business — Accountancy (including C. "P. A.) () Civil Serv Nicholson Cost Accounting Railway Mail Clerk Common School Subjects Bookkeeping Private High School Subjects Spanish fal French Llustrating TECHNICAL AND INDUSTRIAL COURSES Archit ect Architects’ Blue Prints Contractor and Builder Architectural Draftsman Concrete Builder Structural Engineer Chemistry (] Pharmacy Automobile Work Airplane Engines Agriculture and Poultry Mathematics

Persons residing in Canada should send this coupon to the | International Correspondence Schools Canadian, Limited, Montreal, Canada © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. | ing characters. | more clever than when awake, and talks

Another way to adjust the condenser, and perhaps the best way, when possible, is to tune in a powerful local station and then turn rheostat L out. Now remove the tube in socket J and carefully turn on rheostat L again. If the signals still can be heard, adjust condenser H until they disappear or until they become as weak as possible. Tuning this receiver is simple. Set the right-hand dial that controls the rota- tion of coil D (Figs. 5 and 7) so as to throw the set into oscillation. Then slowly rotate the dial on condenser F until a whistle is heard. Adjust the dial on condenser E until the whistle is as loud as possible and then turn back the right-hand dial slowly toward zero until the detector tube stops oscillating. The signals then should be heard clearly, and slight readjustments of the two condenser dials will bring them to maximum intensity. Whenever you get a station properly tuned in, make a record of the three dial settings and you will be able to find the station at the same point again.

The Eight Most Common Dreams and What They Mean (Continued from page 43) missing money.” The grown man was so curious that he boarded a train and went to the house in which he had lived as a child. The bed was still there, but a bolt had been fitted into the hole. He re- moved the bolt, and there at the bottom of the hole was the missing note! Thus was a long and complicated train of thought started by a sensation. In our dreams we sometimes find similar complexity. So many things happen, and they are so interesting, that we often remark upon awaking from a dream, “It was a regular play.” Often in such dreams, the dreamer finds himself taking the part of one of the lead- He is brilliant, much with great wit. But it is significant that he never can remember this witty con- versation after awaking. He simply has a pleasurable sensation of having been important and clever. This is due to illusion. The same effect would be pro- duced by a large quantity of champagne. FROOkS of dream poems have been written in which thoughts occurring in dreams are printed in black and white, but these were the result of somnambu- lism, which is often confused with dream- ing. Somnambulism, which is automatic ac- tivity of the brain, explains how men in their sleep sometimes work out problems which they were unable to work while awake. This automatic functioning, which is identical with reasoning done in the daytime, except that it is done in an unconscious state, is sometimes very dan- gerous. Working in the night as well as in the day, the brain gets no rest and is soon overtaxed. The clarity of a dream depends alto- gether on the time it takes one to wake up. As thoughts gather around a sensa- tion, they result in a curious conglomera- tion, which you straighten out after waking, unconsciously adding fitting ele- ments to them. After a man tells a dream three of four times, it can hardly be recognized as the same narrative. Ordinarily, a dream lasts half a minute or so, although I have heard persons declare seriously that they have ‘‘dreamed for | hours.” An old man told me recently of a dream of running from Indians. He was back in the valley in which he had lived asachild. He ran for hours, terrified and shrieking, yet the Indians gained on him. At last he felt he was lost, and fell to the ground. His wife was shaking him. “Calvin,” she said, ‘‘you have been asleep for two minutes, and you have been struggling like a madman for the last half minute.” Do dreams mean anything? Thousands of dreambooks have been written and no doubt interest in the subject will persist until the end of time, but if I had to answer the question with ‘‘yes” or ‘‘no,”’ I should choose an emphatic “no.” Since dreams are incited by physical: causes, they often tell of disturbances in the body. Some of these are obvious to the dreamer and some are not. A dream may reveal the presence of an illness of which the dreamer is unaware, since in sleep all of the senses are extremely acute. One of my patients, for example, had a series of dreams that a wildcat was clawing at his throat. I discovered that he was suffering from cancer of the throat. But only in the disclosure of physical disorders or similar things, do dreams have meaning. I have no faith in what are commonly known as “prophetic dreams,”’ those that tell one where to find lost finger-rings and missing wills. I WAS talking recently with two sisters about dreams. One of them said, ‘*Oh, sister knows all about dreams. They were making a race book down at her office, and one of the horses was named ‘Superbum.’ Grace had a dream in which she saw bowls of soup. She went down the next morning and bet her money on Superbum, and, do you know, she won, 15 to one?” What could I say? Soup and Super- bum! Surely an omen! All that I can say now is that that young woman is going to lose hundreds of dollars in her lifetime if she keeps on placing her bets according to her dreams. For every dream of prophecy that comes true, there are 999 that do not. Searcely a ship sails out to sea without carrying on board at least one passenger who has dreamed that that particular ship will be wrecked during the voyage. What chance has one to prove dreams false prophets when such is the case?

See page 31.