Popular Science Monthly 1920-12: Vol 97 Iss 6

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300 Pictures of Inventions and Discoveries DRAWN BY J. DUNCAN GLEASON 25 CENTS

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a O : YW au ec you Enjoy more this th Xmas an MURAD? |

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=| y >| | a Popular Science Monthly No Power Loss. ~ 7 with Champion Gasket HAMPION Patented Copper Asbestos Gaskets have been scientifically de- signed in conjunction with our virtually unbreakable No. 3450 Insulator to form a gas-tight seal under all conditions. This effectively guards against spark plug leakage, a common cause for engine weak- ness and uneven running. Champion” Spark Plugs give you the many outstanding advantages of the un- surpassed research facilities of the great Champion institution. Naturally, Champion Spark Plugs have won adoption as standard equipment on more automobiles, trucks, tractors and engines than any other make of spark plug! There is a Champion Spark Plug specially designed for your particular type of gaso- line engine. Order a set from your dialer today. He ~ can supply you. - Be sure the name Champion Gs on the Insulator and the ‘World Trade Mark on the Box Clihmpion Spark Plug Company, __ Toledo, . Ohio. - / a : Pas Charispion Spark Plug-Company of Canada, Limited, Windsor, Ontario “8, .4

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Mee ae ge aS race ntoe— by wariar Rp ane seer oe ee! Sa ETNIES EA, pate. ele! ema” SN A NORRIE Li COE ASE IE CNEL LOGE I I, we ched al aren eaasilasoe deontlinae THIS REGISTERED TRADE-MARK 18 INDELIBLY STAMPED IN THE END OF EVERY BOARD OF TRUB “TIDEWATER” CYPRESS. LOOK FOR IT. CY PRE: ESS tens Eternal” is one of the very best woods for doors,-both inside and “outside, because it does not shrink and swell’ as much as many other woods. And many persons of taste think that. CYPRESS has a hand- ‘some pgrain, one that may be brought out and beautified in the finish. CYPRESS is growing in popularity, both with architects, investors and “private citizens.” Jt must be because it deserves to. Yr Among the 43 SPECIAL NOTICE: Sone ‘F the INTERNATIONALLY STANDARD CYPRESS POCKET LIBRARY, the following volumes contain matter bearing on the above subject—viz.,- Volumes 31, 33 and 39. Volume 1 contains full U. S. Government Report and complete list of ell volumes. Any or all of these will come promptly on your request FREE. Let our “ALL-ROUND HELPS DEPARTMENT” help YOU. Our entire resources ‘are at your service with Reliable Counsel. We invite correspondence with a serious purpose in tt. Southern Cypress Manufacturers’ Association 1249 Perdido Building, New Orleans, La., or 1249 Heard National Bank Building, Jacksonville, Fla. SPECIFY AND INSIST ON ‘‘*TIDEWATER’’ CYPRESS IDENTIFIED BY THE CYPRESS ASSN.’S. REGISTERED TRADE-MARK. IF IN ANY DOUBT, PLEASE WRITE US IMMEDIATELY. THIS REGISTERED TRADE-MARE IS INDELIBLY STAMPED IN THE END OF EVERY BOARD OF TRUE ‘TIDEWATER’ CYPRESS. TAKE NO OTHER. Ss € Ss a Ss é SIX Cg M A M A MM Ai jain ~~ M A os Meas Ree US Derm Tur Markee US Pedram «- Terres oom * Ran US Rome , ss ee eee a wah rity te % 4 te Dia : fe = ra tv: Popular Science Monthly | | ZOpular Science Monthly DEC., 1920 Volume 97-No: 6 Important to Readers Owing .to the paper short- age, the number of printed copies of POPULAR SCIENCE MONTHLY is limited. To insure getting your maga- zine regularly, you should place a standing order with your newsdealer, or send us your yearly subscription of $3.00. AERONAUTICS Five Miles High in a Tank. ................ 21 Wireless as an Aid to the Airplane........... 31 Monoplane Wings Support Twelve Men...... ra Propelling an Airplane by Kicking the Air. ... 47 Rocking Wings for the Airplane............. 58 When an Airplane Collides with a House...;>. . 66 Measuring the Thrust of a Propeller....... .. 66 Down Comes the Steeple................... 67 INDUSTRIAL PROGRESS The Man of the “One Best Way”..........: Ms $8 The Fountain Principle Applied toa Brush.:. 36 Cleaning All the Keys at Once.............. 36 Scraping Paint by Machine............ pe Re 4 A Safety Wrench for Drop-Doors............ 37 Posts that Tighten Fences.................. a. | The Wind Generating Electric Power... 2. >.. ! -37 Illumination Makes Visible some Rameislees. 38 American Rivalry in Dyes...............-.. 39 PURSURI UDWERG «56s co cp oes Fcc se cee 40 Hinged Sides Quicken Car Unloading........ 40 The Garbage-Can as a Source of Wealth...... 40 Testing Dyes by Ultra-Violet Light.......... 41 Illuminating a Line of Type....... geal a Rae 41 She’s a Brute for Strength. ................. 50: Electricity Stuccos the Walls............... 50 A Scrap-Bucket in the Floor................ 50 The New Baby Crane... 600.0. cee ceceewes 50 How to Thaw Frozen Pipes........ SR, ee 50 The Voice of the Thunder God..:........... 51 This Electric-Light Plug Fills a Great Need... 51 A ““Wordometer”’ for the Typewriter...:..... 51 Twine that te Part Paper... .:. 3. ccc steass OR Where Is the ‘“‘Old Man”’................. 52 (Continued on page 4) Copyright, 1920, by the Modern Publishing Company POPULAR SCIENCE MONTHLY is issued monthly. Yearly subscription in the United States, $3.00. Canada, $3.50. Foreign, $4.00. Single copy, 25 cents: Advertising rates on application. Forms close the twentieth of the second month preceding date of publication. Entered as-second-class matter Dec. 28, 1945, at the Post Oface at NewYork under the act of March 3, 1879, . Entered as second-class mat- ter at the Post Office Department, Canada. The contents of this magazine are copyrighted and must.not be..reprinted. without permission. a Hered President; R. C. Wilson, Vice-President; 3. Capen, Secretary and Treasurer. __ Modern Publishing Company 225 West Thirty-hinth St. ‘New York City

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Popular Science Monthly December, 1920; Vol. 97, No. 6 25 Cents a Copy; $3 a Year Waldemar Kaempffert, Editor ——SSSS== Published in New York City at 225 West Thirty-ninth Street coamaad Five Miles High in a Tank Showing how lack of oxygen produces aviators’ brain fag CROSS-EYED, one-legged man ~*~ of sixty may be a good sea-cap- tain; but a twenty-five-year-old dyspeptic will be a failure as an air- pilot. Because a man has flown a few times he is no more fitted to be an air-pilot than a fourteen-year-old girl who has taken a few piano lessons is justified in competing with Hofmann. Who is fit to guide a flying-machine through the air? The Germans in the early days of the war used to select their flyers from the cavalry. English athletes and polo-players proved to be good airmen. Some of our best flyers were once automobile and motorcycle racers. But the rigorous test of war proved quickly enough that athletic prowess and a good physique are not enough. Sometimes weedy, pale clerks proved to be better men in the air than trained By Walter Bannard athletes who had learned to handle a flying-machine. As the war progressed it became apparent that recruits for the flying service must be scientifically selected. The fate of an army depended on the character of the men who fought at great heights, photographed the enemy positions, or watched the fall of shells. Moreover, it was an expensive business to train a flyer and then to find him unfit. It is said that it cost the American government as much as $50,000 to fit a man to fly; but the figure must surely include the damage sustained by the training airplane. At all events, it was known long before we entered the war that the British lost 95 per cent of 21 their airmen, not from bullets, but from physical defects. A taint of epilepsy, the slightest tendency to vertigo, persistent headache, nervous- ness, and easily induced fatigue were sure to prove the undoing of a brave man in the air. So it came about that applicants for the air service were systematically studied, both psychologically and physically, to discover latent disabili- ties. Men were whirled in chairs to test their sense of equilibrium; their eyes were examined; their family his- tory was inquired into; their chest expansion was measured; their height and weight were noted. If all the ideals set up could have been met by any of the applicants, Apollo would have seemed an imperfect weakling in comparison. As a matter of fact, many of the men who were rejected The Pachon oscillometer is used to measure the tension of the arteries; with and without arti- ficial oxygen, at different alti- tudes. The instrument is a modification of that used by physicians to measure blood pressures € Mirzaoff-Boyer

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Ea. by our own army entered the Cana- dian Royal Flying Corps and gave a good account of themselves. Not so long ago the conscience of a United States Army medical officer troubled him because he discovered , that the best flyer in his camp had flat feet! Another flyer of unquestionable ability had slightly defective vision in one eye. Two medical examiners have been known to scratch their heads for half an hour because an ap- plicant, acceptable in every other respect, had a chest expansion one quarter of an inch less than the standard. Now that we have entered the period of commercial flying, it becomes more than ever necessary to determine the - fitness of a man to pilot a flying machine. What is wanted is not that extraor- dinary product, the ace, but a high average type. It is doubtful whether much reli- ance can be placed on the whirling- chair test. Psychological tests, how- ever, are certainly important. It takes a man from nineteen hundredths to twenty hundredths of a second to make up his mind to carry out an act -in an,emergency—his. reaction time. This reaction time may be delayed by fatigue, drugs, and excesses. On the other hand, it is found to be some- what lower at times in men who are physically fit than in others. After a man loses his head there is usually no time for correction in the air. Hence the French may be right in rejecting an applicant who is too slow by even the infinitesimal part of a second. When a pilot loses his head, he may move the throttle the wrong way; he may keep his engine running full speed when he should throttle down; he may switch off the power entirely when he needs all the speed that he can command. Brain Fag Breeds Indifference Fatigue—above all, brain fatigue— may prove as fatal as a poor reaction time. When the brain is fagged out the man has neither the power nor the reason to decide and act. This is probably due to the many impressions received by the brain during flight. He feels alone. He is not afraid. He is simply appalled by the enormity of the enterprise in which he is engaged. Helpless, stupefied, he awaits events Fopular Science Monihly and takes little part in the control of his machine. It is altogether likely that fast pas- senger-carrying airplanes of the future will fly at altitudes far above those at which the highest battles were fought in the air. We are told that above an altitude of thirty thousand feet and more the winds are in the nature of planetary swirls into which a machine should be guided in order to gain an advantage in speed and in economy of power. Now, the human organism was evolved to live on the earth, not above it. As aman goes up, the total quan- tity of air in a lungful decreases. He must breathe faster. At nineteen thousand feet he inhales only one half the amount of oxygen and nitrogen that he breathes at sea-level. At less than twenty-five thousand feet the lack of oxygen becomes distressing. The human organism has the ability of adapting itself to changed condi- tions, but only within limits. How far it can thus compensate itself de- pends on the man. Before the flyer’s limit of compensation is reached, he feels dizzy. Yet heis perfectly happy, although he has lost his faculty of judgment and has passed into a con- dition of partial or total unconscious- & Mirzaoff- Eoyer This is the tank that is used at the Aerotechnical Institute of Saint-Cyr, France, to test prospective air-pilots. On | the next page the interior of the tank is shown. In the background is a pump by means of which some of the air is removed within the tank so as to produce conditions similar to those at high altitudes

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December,. 1920 or thirty thousand feet The man who wants to become an aviator takes his seat within the tank. Air is pumped out to any desired de- gree. Thus the man is artificially elevated to ten, twenty, ness. ‘I’m all right,’ he says as he flies along at fifteen or twenty thou- sand feet. But the tests show that every one of us is affected more or less at such heights. It takes longer to judge and to act; it is harder to read an instrument. Positions of objects are misjudged. Pain itself loses some of its poignancy. Excessive fatigue, nausea, and vertigo assert themselves. For these reasons the oxygen tank has become an indispensable part of the high flyer’s equipment. All the recent records of Rohlfs and Schroeder were made with the assistance of oxygen. It is not impossible that in the high-flying passenger-carrying air- plane of the future the crew and the passengers will sit in hermetically sealed compartments filled with oxygen supplied from tanks. Otherwise pas- sengers must wear oxygen masks. Often a pilot crashes at the end of a rapid descent. He has no recollec- tion of what happened; he lost con- sciousness and was actually asleep. This is highly significant; for this is a state that is induced by an ample sup- ply of oxygen or fresh air at full pres- sure after a period of degradation. It is a phenomenon often met with by students of the low-oxygen problem. It occurs in a wide variety of condi- tions—in miners escaping damp, in city firemen after coming out of smoke, in the older type of submarines on opening the hatches after submer- gence, in persons who are given oxygen after overexertion on a mountain and after low-oxygen experiments in the laboratory. But in none of these con- ditions are the consequences so serious as for the aviator. The Value of the Oxygen Tank Oxygen plays such an important part in flying that one of the most important tests of physical fitness consists in discovering how a man will behave when he is partially de- prived of it. The man is not carried up into the air to be tested, partly because it is unnecessary to do so and partly because the conditions there are against scientific observation. He is placed in a tank from which some of the air is pumped. Thus it is possible to climb, barometrically speaking, to any desired height. 23 The man in the picture wears an oxygen mask, so that he is quite comfortable, even though he may be in an atmos- phere equivalent to that of five miles altitude. instruments record his condition Bic! 2 © Mirzaofi- Boyer Various These tanks are now employed by the medical officers of all armies. By their means the truth about a great many airplane accidents has been de- duced. The subjects vary in every conceiv- able way. The man who has a “weak heart’”’ is usually found at the bottom of the list; he can stand very little oxygen reduction, At the other ex- treme is the man whose powers of compensation are so good that he can “go up’ in the tank to twenty-five thousand feet and show but a slight change in adaptability from the normal, In these airtight testing chambers, or tanks, from six to ten men can be tested at a time, if need be. Oxygen can be inhaled from a tube, with the resu't that, although the artificia! altitude may be thirty thousand feet, the faculties are normal. The effect of high altitude on the heart, breath- ing, and nerves without oxygen can be noted. All the effects of a fall are obtained by allowing the air to enter the tank rapidly. Thus the baro- metric conditions, that obtain during an actual flight can be imitated.

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Scan Rk Be NTT Ge = ci Cnaipettsnird ese capita ner eather NIN A TT SM a = eel Na ne, a ain ce arin, Aaa ara Aan de Poputar Scrence Monthty Trapped in a Sunken Submarine > How I drilled through steel for eight | hours to save the crew of the S-5 By William G. Grace Chief Engineer of the Steamship “‘ General G. W. Goethals”’ engineer of the Alanthus HE bell in the engine- | room rang with the signal to stand by, which meant that I was wanted on deck. When I got there, I found the cap- tain looking hard at a ship that was standing off on our starboard side. To men familiar with the sea, a ship is just a ship, but this one had something strange about her. It looked as if something was strung al- most upright across her bow. “‘What’s that against her bow?” asked the captain, handing me the glasses. I looked carefully, but the light was none too good —it was getting close to six o’clock in the evening, and the best I could make out . from our distance was an object that looked like an airplane strung over the ship’s side and resting in the water. “That’s no. airplane,” said the captain. “She wouldn’t have an airplane in that position.” Then, as we drew closer to the vessel, the startling truth became known. An Inveried Submarine Inclined at an angle between 60 and 80 degrees was the unmistakable body of a submarine, stern sky- ward! As we came closer, a voice called through a meg- aphone: across the water from the Alanthus,- the ship that was standing by the submarine: “There are forty men im- prisoned in this submarine. Come help get them out. They’ve been in there rine. teen inches. with his assistant for eight hours. about two o’clock in the morning the chisel had cut the space between the last of the holes. S-5 Chief Engineer William G. Grace, of the General G. W. Goethals, has given the Popular Science Monthly a graphic account of the part he and his assistant, R. McWilliams, took in the rescue of the crew of the S-5. The Secretary of the Navy has pre- sented a gold watch to Captain E. A. Johnson, master of the Alanthus, the first ship to reach the disabled subma- Chief Engineer C. Jacobson and Chief Engineer Grace will also receive a gold watch, while Captain E. O. Simson and Assistant Engineer McWilliams are to receive binoculars. It was a man’s job to drill through tough steel the number of holes neces- ing. sary to make an opening eleven by four- Engineer Grace worked. At break all records. William G. Grace, who tells the story of his rescue of the had been working. As soon as we realized the situation, Assistant Engi- neer McWilliams and I snatched up the tools we thought would be requiredi We took several chisels, a steel hand-drill, and an “old man.” This is just a pet name for the drill-post necessary to press the point of the drill firmly down upon the hard steel plate. An electric hand-drill with: out a feed screw would have been useless; we should not have had the strength to press it down upon this tough steel to cut the holes. MeWilliams and I climbed down a ladder from the bow of the Alanthus and took our place on the slant- ing plank. The rise and fall of the swell made of our scaffold a very unstable place, but it had to do. How the Submarine Sank Right here I shall stop to tell how the submarine happened to be in such a fix. It was about fifty-five miles off Cape Henlopen when Lieutenant-Com- mander Cooke gave the order for a “crash dive.” This is a maneuver that fol- lows a long, swift run on the surface, and is merely a practice in quick submerg- It had been success- fully tried the day before, but this time it promised to Every man was at his place, the hatches were closed, and the air ballast was forced out as the water rushed in through the water doors. The submarine no thirty-seven hours already and can’t hold out much longer. Bring what tools you will need. We haven’t got anything but a hammer.” We were about thirty miles off the Delaware breakwater, and the sea was calm, though there was the usual ground-swell always to be found on the open water, no matter in what part of the world one may be voyaging. The propeller rods and screws of the sub- marine were high and dry. The cap- tain of the Alanthus had leashed one of the rods to his ship in case the sunken boat should slip from her present position. A rope was fastened entirely around the body of the sub, and to this was tied a plank, which made a kind of scaffold upon which the 24 sooner began to sink than something was found to be wrong—the bow was settling faster than the stern. A quick inspection soon disclosed the terrible fact that one of the ven- tilators had refused to close and that the water was flooding the forward living spaces. Every effort to close the air-intake valve failed, and the bow of the

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December, 1920 , -Y, - How They Saved the Trapped Crew of the S-5 When the S-5 went down, her bow struck the bottom at a depth of 255 feet, and her crew was forced to take refuge in the cramped quarters far up in the stern of the boat. Here they were imprisoned until Engineer William G. Grace, of the steamship General G. W. Goethals, succeeded ia drilling holes to make’an oval opening eleven by fourteen inches in diameter in the stern. The gasoline vapors and chlorine-tainted air poured out of the holes, almost stifling the men as they worked in the open air. A small hose connected with a pump on board the Alanthus was run through the small opening that the imprisoned crew had at first suc- ceeded in drilling, but the amount of fresh air it was able to supply was insufficient. The imprisoned seamen were then hoisted to the deck of the Alanthus nn

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X\ ; struck bottom at a depth of about hundred and sixty-five feet. Water had rushed into the torpedo- room at the forward end of the boat, completely flooding it. In the control- room at the center of the boat, and also in the motor-rooms, there wa3 water. Something had to be done, and that quickly. Finally the mischief-making ventila- the hard sandy bottom of the sea. The temperature inside of the com- partment, even when the holes were admitting a small amount of fresh air, must have been close to 110° f. Although quickly exhausted, work- ing in darkness in foul air, by relieving each other at frequent intervals the Pepular Secence Monthly could they get by this crude device— but they imagined they were getting it, and that, strange though it may seem, helped them. This is how I found them when MeWilliams and I crouched upon the plank, trying to cut into the tough steel with a diamond-point chisel. It did not make a per- ceptible impression inthe tor was closed, and an effort was made to start the air-salvage system. The water had reached the storage batteries, and not only had it put the pumps out of com- mission, but deadly chlorine gas was being generated. The men were choking with -the bad air and fumes, though most of them had donned gas-masks. The lights had been ex- tinguished with the flooding of the batteries. The submarine, being flooded in the forward compartments, was tilted bow downward at a sharp angle. The commander figured that, the depth of the water being one hundred and sixty-five feet and the length of the boat more ‘‘crash dive.’’ Could It Have Been Avoided? Could an automatic device have prevented the S-5 from submerging with her ventila- tors open? Down went the submarine in a But the outboard air-valve from the control-room was open, and the water rushed quickly into the ventilating system, finding its way through the induction valves and flooding the torpedo-room and forward living quarters. A device that would make it impossible for a submarine to submerge with any of her ventilators open would be the best way to prevent future accidents of this kind. Various devices have been tried without success. best alternative is to see that all the ventilators are closed before the boat submerges. than two hundred feet, the stern must be prac- tically above thesurface. Herelay the best chance of rescue. The boat it- self was acting like a long buoy, mark- ing above the sea’s surface the place where it had sunk. Trying to Drill to Daylight The gradual increase in the chlorine drove the members of the crew toward the stern of the boat. They sealed the bulkhead of the compartment into which they were crowded—forty men breathing the same foul air, smothered in total darkness, choking with the fumes of gasoline and chlorine! There was just room for one man to stand above the others in the narrow space at the stern of the boat, and here it was decided to attempt to Grill through to daylight. The blast of foul air that came from those holes nearly overcame us as we worked. The odor of gasoline vapor indicated that it would have been un- safe to have used an acetylene torch to cut through the steel, even if we had possessed one. Mixed with the hot gasoline vapors was the occasional irritating whiff of chlorine, for some of this deadly. gas was still leaking into the engine-room, where the men were standing on the bulkhead partition. Two hundred feet, or thereabouts, of the long boat was below them slanting downward, water-filled, and resting on men succeed- ed in drilling a row of holes five eighths of an inch in diameter along a line seven inches inlength. For weary hours they worked, and then the drill was damaged beyond further possibility of use. Through this small aper- ture the crew succeeded in poking a rod at the end of which they had fastened a bit of cloth, and with this they tried to signal a ship that they could see through their peephole. Their spirits sank when it passed without seeing them. The “Alanthus”’ to the Rescue At last, after being in their terrible predicament all night, the steamship Alanthus caught sight of them and came to the rescue. But the Alanthus had no tools aboard except a heavy sledge-hammer, and with this the en- gineer of the Alanthus succeeded in denting inward the strip that the men had drilled in the thick steel plate. Through the hole was run a hose attached to one of the ship’s pumps, and an effort was made to pump air into the compartment, Not much air 26 steel, which tomeseemed the toughest material I had ever encountered. A little later, by hold- ing the drill with all my strength against the side of the plate, I managed to drill through, making a hole large enough to get a bolthead fixed to hold the base of the drill- post. With the radius per- mitted by the arm of the drill-post I was able to bore a number of other holes, changing the posi- tion of the ‘‘old man”’ as the limit of the swinging arm was reached. We Break Through - Working hard and persistently from sunset until about 11 P.M., I succeeded in getting two thirds of the holes neces- sary to complete an oval fourteen by eleven inches. This was the size of the opening that would be large enough to let even a large man get through. By two o’clock in the morning the sledge-ham- mer and chisel had com- pleted the task, and the plate was actually removed. The groans of the nearly stifled men, the sounds of their vomiting, and the outrush of putrid air, all inspired us to work like mad. With the removal of the plate, the actual work-of rescue began. One by one, the half dead, stupefied seamen were drawn out of their tor- ture-chamber. One by one, they were hoisted in a canvas sack to the deck of the Alanthus. But for the clear-headedness and courage of the crew of the submarine, not one but many of the imprisoned forty would have perished. They have only their coolness and the in- trepid guidance of Lieutenant-Com- mander Cooke to thank for even a possibility of their rescue. To Captain E. A. Johnson, master of the Alanthus, and Captain E. O. Simson, of the General G. W. Goethals, as well as to my assistant, R. McWilliams, they owe their good fortune fully as much as to my own effort. The Popular Science Monthly D eepcmcmesceconoge a ee in ol -~ de tr m-th wilt tohh oar tt et fC aatamh tatent tu

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December, 1920 Here Are Some New Jobs for the Automobile Jack This man did not possess a_ vise. So he made one by adjusting a jack and a block of woced in a doorway Stoves are heavy, but not too heavy for an automobile jack to lift. Next time you have to scrub the kitchen floor, jack up the legs of your stove and make a good job of your cleaning Window stuck? Take two thin boards and a jack; adjust them to position shown here and work the handle New York’s Machine-Gun for Mobs NEAT little gun, weighing only seven pounds altogether and measuring two feet in length, is the latest acquisition of New York’s police department. The little terror spouts forth huge .45-caliber bullets at the rate of fifteen hundred a minute as long as the magazine holds out. With its high rate of fire,—higher than that of the fastest of speeded-up machine-guns used on airplanes,—its small size, and the ease with which its fire can be controlled, the ‘“‘sub- machine gun,”’ as its inventors call it, is without doubt the most formidable firearm in existence. The gun, as made for use in America, fires the caliber .45 automatic army pistol cartridge. The bullet, nearly a half inch in diameter, weighs 230 grains, or eighty grains more than the bullet of the service rifle, and is nearly double the weight of the bullets com- monly used by the police in their revolvers and pistols. The velocity of the bullet is low, and the extreme range when the gun is pointed at a 23° angle is only fourteen hundred yards, but it is far more efficient than the service rifle bullet at the moderate ranges of one or two blocks at which rioting would take place. The re- coil is low, and in spite of the light weight of the gun, it is very easily controlled. The ammunition is fed to the gun either by a flat box magazine holding twenty shots and projecting below the line of the gun, by a disk magazine holding fifty shots, or by the same type holding one hundred shots. The fire is controlled by the trigger. One December, 1920 By Captain E. C. Crossman shot can be fired by pressing the trigger and quickly releasing it, or the entire magazine may be discharged, or any number of bullets in between. The gun may be furnished with a stock and fired from the shoulder, but in its form for use on mobs or other “‘spray’’ work it has only two grips, one for the right, the other for the left hand, and it is fired from the level of the waist. The writer has fired one a number of hundred rounds, and, with consider- able experience with the two types of weapon, finds the little submachine gun much easier to control in firing The adopted by the New York police department, spouts bullets at the rate of fifteen hundred a minute; one shot would riddle an escaping automobile “submachine gun,” recently 27 than the better known heavier sixteen- ‘pound “‘light’’ Browning automatic rifle used by our troops in France. At from fifty to one hundred yards it is no trouble for one at all accustomed to the gun to riddle a man, while the entire front of a mob could be swept away from one curb to the other by a single burst. The gun has only a dozen parts, astonishingly simple when compared with the simplest of Browning’s auto- matic rifles. Any tyro can take it apart for cleaning and repairs without the use of a tool. The greatest effect of the gun with mobs would be through its moral suasion. When it is fired there is simply a roll of shots, a veritable roar, beside which the machine-gun with its five or six hundred shots a minute sounds as slow as a minute-gun. The empty cases fly in an unbroken stream from the ejection port. One burst over the heads of a mob not too ugly, and therefore not deserving of sudden death, would result in its instant and speedy dissolution. Fired at an escap- ing automobile, at which the pop- ping of the average policeman’s revolver is as effective as a bean- blower, it would riddle the car and ‘those within it. The gun was invented by Com- mander Blish; of the United States Navy, and General John T. Thomp- son, retired, formerly Assistant Chief of Ordnance of the Army, and during the war chief of the Small Arms Division, which gave to the Army the millions of resigned British rifles, known as our Model 1917.

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tata ioe af are tla tae Ane PID te ME ee a eT OS peeneeigieneaceresnerenraneree stay rete vnesretater vy essere YS eT ee ae Ts Twins, Triplets, Quadruplets—Why ? Heredity, which plays a very important part in our lives, also affects our birth AS environment or heredity the con- alike. Heredity wins out. trolling interest in the lives of twins? Let us consider twins in general. Fraternal twins, who There develop from unrelated are two kinds—identical twins and fraternal parent cells, are not twins. Identical twins come from one single necessarily alike. Each cell, which in the process of development one inherits the partic- happened to break in two and continued to ular family traits with cevelop in two separate halves. Fraternal which his original cell twins, on the contrary, come from two wasendowed. They may Gistinct, unrelated cells that for some reason’ be of different sex, dif- began to develop at the same time. Identical twins are very much alike. acter, size. They come from the same tiny parent cell, whichso marvelously contains character- istics and traits of both the father and mother. Investiga- tion shows that iden- tical twins are not only alike physically, but. that they are also alike physiolog- ically and mentally. They often care for the same foods, like the same people, get the same diseases, even though living in different places, have similar hand- writing, similar tastes, hobbies, and abilities. The iden- tical twins pictured on these pages all tell the same story. Some of them have been living in differ- ent environments all their lives, yet they feel, think, and act ferent complexion, char- Pe ee . ¥ Popular Science Monthly Once more You might almost think this a freak photograph showing the same person twice, so alike are these twin brothers. The one on our left is the Rev. Edwin C. Brown, a Congregational minister His brother’s name is Edgar, and he is a bookkeeper. Both were born with defective eyesight—one in the left eye and the other in the right. They walk alike, have simi- lar tastes and body weaknesses The oranges and the girls are twins—all from California. The only difference we can see between the girls is that one shows a little more of her teeth than the other. They recently entered a beauty contest three survive. Even in the case of triplets, one or two of them is very apt to be frail and frequently does not survive. The higher the form of animal life, the smaller the num- ber of young at birth. Certain species of fish lay thousands of eggs atatime. Rats, mice, cats, dogs, rabbits, and guinea-pigs are prolific breeders, pro- ducing from three to twelve offspring heredity and not environ- | | These are the Grosvenor twins. ment scores. Is twinning inherited? Is a woman who is a twin more apt to give birth to twins than a woman in whose family no twins have occurred? Statistics show that twinning is apt to recur in certain families. In some families the proportion rises to twenty per cent. It is certain that twinning is not accidental, but de- pends on certain con- stitutional factors of the parents. Occasionally triplets are born, and there are They on record cases of four, at a birth. Sheep, cows, horses, and J divided the highest honors at Amherst. One of them is the builder and director of the National Geographic Society and the other is an assistant attorney-general five, and even six chil- dren at a birth. But it is very rare that more than 28 Mrs. Vera De Mott, of Battle Creek, Michi- gan, and her twin. Which is which we do not know. Though living apart since they were three years old, their characteristics have remained similar

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December, 1920 elephants, however, seldom have more than one offspring. It is a case of quantity versus quality. Single off- spring are usually much further de- veloped than individuals in a large litter. The young of mice and rats are without any hairy covering, whereas the lamb, calf, and foal are covered with hair. Their eyes are open and they are able to walk. Kittens and pups are hairy at birth, but they can- not see nor walk. In most species the number of young in a litter is indeterminate. The Texas armadillo, how- are so much alike that their mother often washes one of them twice and lets the other go unwashed. They are so attached to each other that they are actually unhappy when separated. They become hungry and sleepy at the same time. Both of them are clever acrobats and work for the movies side by side. The Ploger brothers, of Owosso, Michigan, look alike, weigh the same, have identical voices, similar tastes for operatic music, but differ in their taste for mathematics. Thus one is a machinist and the other a commercial man. Rose and Louise Briot lived to- gether for the first eighteen years of their lives, needing no other chums. Since then their lives have varied greatly. One is a widow and lives in the West near her children and grand- children. The other lives in Chicago and has no children. In spite of their different environments, they remain very much alike. As girls they often voiced each other’s ever, is fairly constant in the matter—producing four young at a birth. They are ‘‘identical’’ quadru- plets, all coming from the same original cell. Man and the armadillo are practically the only ani- mals that give birth to “‘identical”’ groups. Thorndike, the well known psychologist, says that you can’t definitely tell by looking at a pair of, twins whether they are identical] or fraternal. Fra- ternal twins often resemble each other very closely. But at birth the difference is plain. Identical twins are surrounded by a com- thoughts, and now- their letters cross repeatedly. Decidedly different are the Cooper twins, who live in Newark, New Jersey. They are four years old, and yet one of them is twice as large as the other. The larger boy has long, thick hair that needs the attention of a barber. His brother still has a baby- like fuzz on his head. The American Genetic Association is making an effort to secure greater knowledge of twins by actually studying them. More than six hundred twins have generously offered themselves for the purpose, and the results mon vascular envelope; fraternal twins have sepa- George and John Seiffert, of York, Pennsylvania, They are eighteen years old, and thus far along in are most interesting. Each pair of twins has are ‘“‘identical’’ twins. their history their likes and rate envelopes. Thus their heredity is the dislikes on almost every ye pe: xy tell — heabie Robert and Frank same; that they look subject have showed no of them furnish vatuaple Michel, five-year-old boys, alike is readily seen. signs of difference physiological information. Making the Railroad Crossing. Safe RADE crossings of railway lines and automobile roads are dan- gerous enough in daytime and clear weather, but at night and in foggy weather the customary means of pro- tection (bars and light signals) are often insufficient to prevent serious ac- cidents caused by human carelessness. The bar-and-light sig- nal of warning shown in the illustration has been tried with success in Germany. The bar con- sists of a light retal tube long enough to reach across the road. It is painted in contrasting colors to attract atten- tion. The bar is hinged to a post at one side of the road and when not in use is in a vertical posi- tion. When a railway train is approaching, the bar is tilted to a hori- zontal position until its free end rests in the fork of the post on the oppo- site side of the road. In daytime, if the air is clear, the con- spicuously painted bar will give suffi- cient warning to automobilists to prevent accidents. The light signal, which is used at night or in foggy weather, consists of a square lantern securely clamped to the middle of the bar. A powerful acety- In the daytime the bright colors of the bar warn the traveler of danger, and at night the brilliant light serves the same purpose 29 lene light within the lantern illumin- ates the two glass faces of the lantern, and displays in strong contrast the crossing symbol in dark outline, as shown in the picture. The burner of the lantern is con- nected by means of a small-gageslender tube with the steel tank in whichthegas supply under high pres- sure is kept. This tank, which holds enough acet- ylene for several days, is attached to the end of the tube, together with the counterweight and a device which controls the flow of gas to the burner. When the bar is not in use and there- fore in a vertical posi- tion, only enough acety- lene is supplied to feed the small pilot flame in the lantern. When the bar is lowered, the gas valve to the illuminat- ally opened, the gas enters the burner and is ignited by the pilot flame. ing burner is automatic- '

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A Ss RN A PON AT, i | . #4) Wireless Guides the Aviator through Fogs ' Oulside Passengers Rubber Sushenders hrolecting inslrument from shock rr ja , ows = Aeucoonelll (Tw ( ky © Modern Publishing Cc. When an aviator flies above a fog-hidden or cloud-hidden landscape, the matter of landing becomes hazardous. How is he to find himself? The radio direction-finder comes to his rescue. There are two methods of applying this remarkable wireless device. On the left-hand side of the above picture is seen an airplane asking its position from two ground stations which are in communication with each other and the machine. The angle and intensity of the wireless received from the airplane establishes its distance and direction © 30 Direction -Finding Aerials arranged tn pian a cross along rear Shars of wings and above and ve or : vous fuselage Tubes lgading nsfrumenis ERIOR or STATI from each station. A brief calculation enables them then to inform the aviator where he is. The second method (illustrated by the airplane near the right-hand center of the above picture) shows the aviator determining his position by his own calculations. His in- struments tell him the direction from which the ground signals come. This is accomplished by three loop-aerials, one mounted fore, another aft, and the third crosswise along the wings of the airplane. Two ground stations are sending continuous but different signals, easily distinguished Drawing by S. W. Clatworthy De sti kn ing fig dir otk you col the the dis fog pla air tra ou’ she to tu de wil the wi

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December, 1920 Wireless ERE you ever lost in an airplane, at sea, in a forest, or on the streets of a strange city? If so, you know there are just two ways of find- ing out where you are. One is to figure it out for yourself by noting the direction of two landmarks, and the other is to ask somebody else to tell you. Before the days of radio you could find out only if you could see the two landmarks or be seen from them, unless you were within calling distance. Now it can be done in a fog or. above the clouds. The pictures on the opposite page show how air- planes may use either method. The airplane on the right-hand side illus- trates the first method of figuring it out for yourself, and that on the left shows the second method. Both Depend on Radio Both methods depend upon a phe- nomenon of radio receiving. If one uses a loop of wire as an antenna for receiving, he will find that when the plane of the loop points toward the station that is signaling, the signals are best received. When the loop is at right angles to this direction no signals can be heard. For all po- sitions between these two the signals as an Aid to the Airplane By John Stuart may be heard, and they get stronger as the loop is turned away from the right-angle position. = In the right-angle position both vertical wires are equally distant from the signaling station and are always affected alike. If the current induced in one vertical by the ether wave is up, that in the other will also be up. The currents in the verticals then neutralize each other, leaving no cur- rent in the loop to affect the detector of the radio receiver. This is shown by the middle picture on the left. This picture of a direction-finding station shows two fixed triangular loops instead of one that can be ro- tated. The currents from these loops pass through two small coils in the box shown immediately below. These coils are set at right angles, like the loops. There is also in the box a third coil which may be rotated. In it the currents in the two fixed coils induce a current. This induced current is then led to the detector. The movable coil, under these conditions, acts just like a single loop antenna and so gives an in- dication of direction. In the first method for navigating an airplane, the radio operator calls two land stations and asks them to tell him where he is. Each of these finds on his position with a direction- finder and reports his angular position. The upper picture on the left side shows how the radio stations in England operate to locate an inquiring airplane. From .the two diroctions the pesition of the airplane is known and its operator may be informed. The Direction-Finder as a Compass The other method has recently: been demonstrated in England by the Mar- coni Company. It is illustrated by the picture on the right side of the page. The ‘radio operator on the airplane finds his own position by observing his direction from two fixed land sta- tions, which are always transmitting but sending different signals, so that’ they may be distinguished easily. The loops are mounted, one fore and aft and the other crosswise along the wings of the airplane. The coil-box used on the airplane is of the same’ type as that for land stations. By plotting his direction from the two’ stations the airplane operator finds where he is. He may also use his direc- tion-finder as a sort of compass and maintain his flight in any direction. Turn Your Car Over with One Hand Working on automobiles in comfort means O longer is it necessary to get out and crawl under the automobile to repair it. With one hand you can turn your automobile over! Here is a device that has a track and a small windlass to pull the automobile from the floor to the track. It is equipped with simple appliances to hold the machine so firmly that when it is over- turned there will be no strain on the chassis. When the automobile is thus in place, a child can turn the handle of a crank that causes the car to rotate at any desired angle. What a relief to see the workings on the underneath part of one’s automobile without having to lie. flat on one’s back on the floor! An inclined runway, or skids, lead from the floor to the longitu- dinal tracks forming the base of the cradle, A small windlass draws the car up on the cradle, and there is a small crane that can be used to lift out the engine when necessary. The entire equip- ment weighs less than fifteen hundred pounds; it is made of “knock-down” parts that can be quickly and easily assembled. Special jacks are provided that enable one to take off the front or rear wheels while the car is being which may be placed anywhere without be- ing braced or an- chored to the ground. The equipment weighs less than fifteen hundred pounds. A wind- lass draws the car up on the cradle over an inclined runway $1 better repairing rotated. The repairman, instead of lying on his back under the car, sits down and comfortably reaches the parts that require his attention. It is a scientific fact that a person in a comfortable position is more efficient in any work than when he is straining physically while working. It is es- timated that at least, four times more work can be done in a given time by making’ use of the device that turns the automobile over. ; The man who works in a’garage finds in this. new .device a preventive of many unnecessary aches and pains. It is almost _un- necessary to observe that liability to ac- cident is considerably reduced owing to the careful inspection * made possible by the use of this adjustable Tse automobile rack. ee = i ;

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sneer say venesrreervsninteee personas ree eeecin ARO SH REO Ry poeepeorentrest tay “oi rerererres LE paren: Popular Science Monthly How Furs Are Made into Garments They’re hard to sew and hard to clean Preparing animals’ skins and manufacturing them into fur coats and muffs and neckpieces has grown into a huge industry re- quiring a high order of skilled workmanship. The padding and lining of a garment must be*sewed to the skin, and the stitches must not show on the outside. How is it done? A special sewing-machine needle is used that pierces the skin only half way When your coat gets that worn, scraggly look, you take it to a furrier to have it “‘glazed.” What does he do? Scrubs your coat with water and a stiff scrubbing-brush; and when it dries, it is soft and smooth. Of course, it’s all in the way he scrubs ieee stretched a a , \liad PoP 1 Tae A) Shaping a fur collar is not so easy as it may appear to be. The collar has to be into shape. This is done by nailing it to a board, where it is left for several days 32 Furs are cleaned by the use of sawdust and sand. Above you see a furrier putting a handful of sand in a large revolving drum. Then he will put in the muff, close the drum, and turn on the switch. The fine grains are forced into the fur, removing the dirt Dec

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December, 1920 How the Big Searchlights Are Tested Light is measured by a “photometer”: these pictures show what it is and does This huge scale measures the diameter of searchlight beams. It is located 2300 feet from the searchlights. - The shed at the right houses a photometer Left: The front of the integrator. It has a diameter of 110 inches and ‘is provided with an_ iris shutter, which adjusts the open- ing to the diameter of the search- light beam under test. The in- tegrator is on wheels so that it can be moved easily Right: The-business side of the integrating photometer at. Sche- nectady. A photometer measures the candlepower of light sources. The integrator is a_ reflector. - which-collects the light and pro- * jects -it into the . photometer. The measuring unit of the_pho- tometer is at the center of the in-_ tegrator, where the light from the © searchlight under test is collected and its candlepower measured Ne ae Beams of light are directed through these big holes to cut off all the stray light. By-‘‘stray light” is meant light that is not ‘part of the beam itself. If this light reached the integrator, it would be im- possible to calculate the beam’s actual candlepower A military searchlight of the fortification type is shown at left. “At the right. is a.sixty-inch portable army light. The air of the photometer room is kept as free from dust as possible by suction fans and .air-filters. Dust interferes with results The big lights out of doors for testing under __ actual operat- ing conditions

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Se ae isa aap meee eat Uy AE ETS A AE (NRE Ne paeraral oreo Sn Sr arse er verona “Oe PRORNO ETSY NTIL I talked with Frank B. | | Gilbreth, I never suspected that the ordinary motions we make in going about our every-day affairs could become a subject of fascinating interest. “All human activity,” says Gil- breth, “‘is a matter of motions and de- cisions.”” All of us, even the experts, make needless motions, or wrong mo- tions. We suffer unnecessary fatigue because we don’t perform our usual tasks in the One Best Way. Finding the One Best Way Frank B. Gilbreth is a consulting engineer. His specialty since 1911 has been scientific management. He probably knows more about human motions and the causes of fatigue than any other man living. When Gilbreth graduated from the Boston public schools, he prepared to enter the Massachusetts Institute of Technology, intending to become a contracting engineer. But he changed his‘mind. It had oc- curred to him that he could learn more about management by getting out into actual. construction work than by staying in the classroom. He had an idea that the By Fred C. Kelly only way to handle problems of man- agement competently was to know a few of the trades with which he might have to deal. So he started in and learned twelve different trades before he called that part of his edu- cation complete. When he began, as a mere young- ster, to learn various trades, Gilbreth found that a big obstacle to his plan might be the time required to become proficient in each one. The only way to overcome this was to learn a trade more rapidly than the average appren- tice could learn it. One of the first things he attempted to learn was to lay bricks. . Now, bricklaying is. one of the old- est of trades—dating back. two or three thousand years prior to the birth of Christ. There are even historical data on which to base a belief that bricklaying is at least seven thousand yearsold. And yet, as Gilbreth noted, in all those seven thousand years it had improved, as to method, scarcely at all. Gilbreth studied the methods of various bricklayers—t he poor workmen and the best ones, and he stumbled upon an astonishing fact of great importance and significance. He found from the lazy man! Most of the chance that he could learn most - Popular Science Monthly The Man of the “One Best Way” How Frank Gilbreth studies men and their ways improvements in human motions that eliminate unnecessary movement and reduce fatigue have been hit upon, Gilbreth thinks, by men who were lazy—so lazy that every needless step counted. Another important thing Gilbreth noted was that the so-called expert factory workers are often the most wasteful of their motions and strength. Because of their energy and ability to work at high speed, such men may be able to produce a large quantity of good work, and thus qualify as ex- perts, but they tire themselves out of all proportion to the amount of work done. “Men were still working on scaffolds with the bricks and mortar on the same level as their feet,”’ he says, “‘in- stead of on scaffolds with an extra row of planks, so that the materials could be level with their hands.” Imagine the waste of energy in bending over to the floor every time one picks up a brick or a trowel of mortar, when the entire operation could be accomplished without moving anything except the arms. The Great Inertia of Habit Why had there been so little im- provement in methods? Simply be- cause of the great inertia of habit. As an example of how awkward it is to make a slight change of_habit ar method, suggests Gilbreth, try taking a cup of coffee and a doughnut, with the coffee in the left hand and the “The One Best Way of performing an act is a matter of rhythm and the saving of effort,” says Frank Gilbreth. _ Gilbreth has studied the motions of baseball-players, fenc- ers, pianists,.and.workers of all kinds, and has concluded that there are fundamental laws of motion applicable to everything from shaving yourself to removing an appendix et @ A Cees eet OU lO a a a ee eee ae

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en ia 2 December, 1920 doughnut in the right hand. If you think such a revolutionary change in habit will not upset you a bit, just try it! Unless you’re careful, you’ll find yourself with your hands crossed and your brain in a whirl. So, Gilbreth worked out an entirely new method of bricklaying, which makes it possible for a man to have bricks served to him at the level of his breast, to avoid the useless bending. A whole book could be written on just this subject of bricklaying and how Gilbreth revolutionized bricklay- ing practices. Gilbreth. makes a _ motion- picture of a master mechanic, a handkerchief-folder, a tatter, a champion baseball batsman, or an expert fencer, for example. A specially contrived clock, the hands of which record time down to the millionth part of an hour, also appears in the picture to indicate the elapsing time, which is necessary because the crank of the camera or that of the pro- jector cannot be turned at pre- cisely the same rate. Gi!breth has only to study a film to tell you to the hundredth part of a second how long it took to make a motion. The cyclegraph, on the other hand, consists simply of a small electric light fastened to an arm, a leg, or a head. On an ordinary photo- graph of a man so equipped streaks of light appear as his arm, leg, or head are moved—the path of the motion. The cyclegraph helps out the motion-pic- ture machine; it reveals much that the machine cannot reveal. It synthe- sizes motions; the motion-picture machine merely analyzes motions. After years of study, and by means of his moving-picture machine and the clock with split seconds, Gilbreth has learned that all speed champions, whether typ- ists, bricklayers, o oyster-openers, skilled wrappers of bundles in mail-order houses, or sealers of tin cans, have certain motions in common. They proceed from one motion to the next with the minimum of changes of direction. They have rhythm where an un- skilled worker might have jerks. In short, every good motion is based on two factors: rhythm . and. economy of effort. Gilbreth has learned the mo- tions of skilled fencers, pianists, famous golf-players,. surgeons, baseball - players, and - others. And ‘he found not only what mo-~ tions different’ experts make, but precisely. how. much time each: motion > requires. © In © _photo-~- graphing differerit _ ‘members - of the New ‘York: baseball. teamy, he™. learned;; among ~~ other things, * that the speed of a ball hurled at many methods. high table. head; shoulder, an arm, or the batter by the pitcher varied from 210.07 feet a second, or two and two fifth miles a minute, to a velocity of two and four fifths miles a minute. Scientific management, says Gil- breth, may be applied to one’s every- day household affairs in scores of ways. Even in so simple a matter as getting To measure the distances of motions, Gilbreth uses This picture shows one of his pene- trating screens erected in the plane of the edge of a It passes through the arms and head of the man, in this case Mr. Gilbreth himself. Double exposure is responsible for the effect produced. The screen is carefully ruled, so that motions may be re- ferred to it for exact measurements dressed or undressed, there is a wrong way and a One Best Way. “Few persons realize,’’ maintains Gilbreth, ‘‘that clothes which are never pressed, but are properly folded, or hung up, each night, will look well longer than clothes which are pressed occasionally, but never folded or hung up.” Gilbreth has proved by actual demonstration that if a man’s clothes are laid out in the order in which they Gilbreth - devented the cycdigsiagl in order to study “human, motions. An électric lamp is attached to the 35 a foot. It moves with the Bupha he sees 3 na Rater: oe heb mare photo- be ~ The’ streaks -o ton the ey an yz c by. a ; reveal: the motions weré } cyclegraph is applied to a typist are to be put on, he can dress himself in less than half the time it will take if he has to stop and hunt each article as it is needed. In other words, it is economical to hunt up “‘other’”’ clothes all at once, when the mind is on such a search. Nearly everybody, by the way, falls into definite habits about getting dressed and undressed. Most of us take off the same shoe first every night—and usu- ally, for some reason, it is the left shoe. Watch yourself and see if this isn’t true. We uncon- sciously follow a regular order in taking off our clothes. One man may take off his collar before removing his shoes, and another may do just the opposite.’ But the point is that he is almost certain to follow always the same sequence. It is interesting to learn just how Gilbreth cut down his shav- ing and face-washing time from twelve minutes to.two. In the first place, he discovered that he can shave more rapidly with one make of safety razor, but more closely with another. So he uses the first razor for “‘the first time over,” and finishes off with the second model better adapted for close work. His most impor- tant time-saving method of all is the use of a brush in each hand for ap- plying: the lather. “Otherwise,” he says, ‘‘your left hand is idle at your side. If it is employed in scratching your leg or in any useful purpose whatsoever, well and good; but if it is doing abso- lutely nothing, why not put it to work?” Now, Gilbreth doesn’t take all this seriously except as an object lesson. He doesn’t advocate a Save Shaving- Time Week, or anything like that. Still, the difference between twelve minutes and two in the morning is not to be sneezed at. Little items like these do not matter much, of course; and.they are mentioned here solely. : be- cause they serve as examples of the effect of habit, and because they show how possible it is to conserve time even in the sim- plest every-day processes. . Right here somebody will ex- claim: ‘‘Goodness sakes, ‘how terrible it would be to live with a man like that—who even washes his face according to a system.” But the truth is that Gilbreth is no crank and he wouldn’t be bad to live with. He is an easy- going, big fellow with twinkling eyes and a-sense of humor, and his purpose in shaving and wash- ing his face systematically is not to save time, but to learn some- thing that he can use as.ans Object . lesson, inorder: to interest ‘people show: « fotned “Yn this photograph the ” “tr saving- time where-it is of gen- uine importance.

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Danae nol ode eR rare ort st sagereptinaprenne ie. = - Pe eae foe sh Oleinetencsl epegnenes-chepensensaemarearsswtne Seno ee fp ener bra fan” AF IGS RT RN RR SO CA RS tN me eS nn nA NN S eekarsen > Popular Science Monthly The Fountain Principle as Applied to a Brush ERE’S a new fountain brush which feeds like a fountain pen. It can be used for cleaning clothes, blacking and oiling shoes, blacking stoves, cleaning typewriters and type- forms, veneering furniture, and many other uses also fall within the scope of this serviceable fountain brush, the handle of which is filled with the polishing liquid. To feed the brush, all that has to be done is to press it against some solid surface. This will release suffi- cient liquid to do the work. When taken from the surface, the brush automatically goes back into normal position and the feed-valve closes. Hitch Dobbin by His Own All the Keys Cleaned at One Fell Swoop AN invention for cleaning the keys of a typewriter, adding-machine, and other forms of key-actuated ma- chines, has been patented by James W. Pennewill, of Silver City, New Mexico. It consists of a piece of heavy cloth cut lengthwise through the middle portion into eight strips, each about a_half inch in width, and separated from each other by a space of about a quarter inch. These flexible strips, arranged over the keys and drawn back and forth from side to side, will clean the tops of the keys. To clean the flat rods under the keys the strips are twisted and inserted against the rods. Riding a Bicycle Over a Right Leg N° longer need the driver of a restive horse carry a heavy weight around with him to fasten to the bridle when he leaves his horse standing. The photograph below shows a method of hitching which is both simple and effective. A strap of the right length is attached to the shafts or tongue of the vehicle and is Bnapped-to-a shorter strap, which passes around one -of the front legs of the horse. The horse is thus prevented from taking a step-forward. ; .. When not in use, the strap is thrown back into the front of the vehicle. _ This invention does away with the old weight-and-bridle connection. The usual ,way ‘of hitching a= horse requires either the use ofa hitching-post. or the cumbersome carrying of a hitching- weight. The new way dispenses with both, or; rather, with the weight, since this mo- tor-driven age: has banished the hitching- post almost entirely from the streets. And All to Photograph a Factory from on High OME TIMES airplanes have been em- ployed to fly over industrial plants to obtain suitable bird’s-eye views; remark- able kites have been built to take a camera up over a factory for the purpose of getting the “‘whole thing’’ in the picture; but this is a tall tower erected to permit a photog- rapher to mount his camera in such an elevated position that just the desired point of view of a certain group of manu- facturing buildings can be pictured. The company’s riggers put up a simple structure which resembled the single mast of a ship. . Up to the “crow’s nest” climbed the camera-man. Needless to say, there was a funny feeling in ‘the pit’ of-the photog- rapher’s stomach’ when: he stood on top of his lofty perch, but it did not prevent him from obtaining a successful camera’s-eye view of the immense works. Railroad Track Ran CE has produced an ingenious inventor who decided to make use of the railroad-tracks when strikes put the trains out of commission. With the aid of a specially contrived frame and three small wheels he has con- verted his bicycle into a vehicle that will run on the smooth steel rails, thus giving him the advantages of considerable speed and small expenditure of energy. The surface of a metal rail offers less resistance than the surface of any but the finest road-surface.- The additional: weight of the frame and the small wheels ngust be taken into consideration, but to offset this the inventor has the advantage of a direct line which is graded perfectly. A railroad does not ordinarily twist and turn as:‘much as a road, nor are its-grades as frequent or as steep as those encountered in the. ordi- nary country road. : Under normal conditions the law will not permit any.one to make use of.a rail- road right of way.

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December, 1920 Scraping Paint by Machine AFTER a summer of hard rain the paint on most automobiles looks dull and dead; whereupon the owners often send them to the factory to be repainted. But, before a new coat of paint is baked on, the old one must be removed. Until recently this has been a long, tedious job. Now there is a machine that will do it in an hour. A gritty paste is first smeared over the paint, and then the machine shown above is moved across it. There are two feet, or kickers, that move alter- nately backward and forward. They are actuated by compressed air. A Safety Wrench for Drop Doors HE workman who releases the heavy drop-bottom door of a freight-car with an ordinary wrench is always in danger of having the wrench swing back at him and break his wrist: But there is now a new . wrench — shown above — in which this dangerous fea- ture has been eliminated. A ratchet and pawl inside the head of the wrench ab- sorb. all the motion. The socket itself is a part of the ratchet member. _ This. new wrench is made entirely of steel and’ has an average tensile strength of sixty-five thousand - pounds. . cylinder formation. A Dearth of Pullman Cars [N the days of. plenty, before the war, even Pullman cars were numerous. Between the years 1905 and 1915 there was an increase of seventy-six per cent in their number, with a smaller increase of forty-four per cent in the number of passengers carried. But in the past five years the tale is very different. There has been a fifty- four per cent passenger increase and only a four per cent increase in the number of cars. This state of things will explain, in some degree, the lack of accommodation on even the best equipped railroads. Put the Wind to Work Generating Electric Power M?°st of our power is obtained from fueltoday. But fuel—coal, gasoline, wood, alcohol—is becoming scarce. A French inventor has suggested that we return to the use of wind for motive power. He has invented a new type of wind- mill for the purpose. Instead of using vanes that radiate from a common center, he uses vertical ones in They are set at such an angle that they will always catch the wind, no matter how gentle it may be. If the windmill has an electric generator attached to it, each time the vanes go round the armature will be turned and a storage battery charged. Thus on exceed- ingly windy days enough electricity will be generated and stored to make up for the small amount generated on days when there is little wind. te ane = ‘Get Up!”’ Says the Record “BREAKFAST is ready!” You grow very tired of saying that, year after year, to the various members of your fam- ily. Why not let the talking-machine say it for you? There is now a clock that, instead of ring- ing an alarm bell when it is set, will release the phonograph lever. A special household record is now made. There are on it all the various sayings which you repeat every day: “Breakfast is ready”; “Hurry up— you'll be late,”’ and so on. When the clock releases the lever, the words of wisdom pour forth. Posts that Tighten Fences (CCRANKING up is all that is needed in order to tighten wire fences when posts-like the one above are used. . Ten holes are drilled in the post and the fence wire is run through them. The post can turn, but it is held fast by means of a ratchet. Should the wire sag in the course of time, the post ean be cranked up to the next notch at one jerk. iron-and in concrete, and will last. much longer than wooden posts. They may be ‘spaced twenty feet apart and yet give she fence sufficient strength. The posts are made both in |

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Ape RT Low fo? ay Fe eae en te cnc ee ihe vee 4 RIT RRR ne PE Shakespeare vs. Les-Angeles’ EH UG B*v'olumes ‘weighing — several hundred pounds each.’ are here'shown. They are filled with “nothing but names. Names of what, you ask? Names of people who visit Los Angeles every year. The Chamber of Com- merce of that city claims that over five hundred thousand tourists visit their city every year. The number of daily visitors ranges from one hundred to twelve hun- dred. Each of the big books contains’ the names of over a million persons on four hundred pages measuring twenty inches by two feet. The thickness of each volume is about fifteen inches. And now that the fair city of Los Angeles has all of these names, what is it going to do with them? Perhaps Los Angeles wishes to show her rival, San Francisco, the exact number cf visitors to the more southern town. It is obvious that she does not share Shake- speare’s scorn of a mere name. WEEE ELE) Illumination Makes Visible Some Comparisons ECOURSE (to __ illuminated graphs as a means of pre- senting its case to the public was taken by a Chicago electric-light company. On a big electric sign over :the entrance to its office- building, the changes in cost of food and clothing, fuel, taxes, and electricity ‘since 1896 are com- pared, to the great advantage of the last named-commodity. The cost of clothing and food from year to-year’is' represented by the top‘line, which rises grad- ually until’ 1904, when it shoots upward. Fuel and taxes, big factors in the cost of producing electricity, are also seen to have initgased: steadily, =>- °° The cost of eléctritity: te the consumer, however, has had a general downward trend. An Old Water-Tower Becomes _ a Home ‘THis man lives high, but he has de- feated the high cost of renting. There was an old water-tower that had not been in use for years near the farm on which: he lived. He decided ‘to buy the place and fix it up to live in.. The picture shows what a good job he made of it. Set in the center of alarge isadieieeiihiee: with its picturesque stairway and ivy- vines, the tower looks like a little castle in some foreign land and very few people would guess right off that it is situated somewhere in New York state. The platform around the top of the tower is used as a porch. Electric lights, running water, steam heat and all the other conveniences of the modern city home are included in the equipment of this house. Popular Science Monthly One Good Bath Deserves Another [Tt is necessary to wade through this pool be- fore you can walk up the stairs. People who bathe in the ocean al- ways carry part of the beach with them into the bathing-house. A Western bathhouse owner had trouble keep- ing his place clean, and he hit upon the idea of placing a small pool out- side the door in which the bathhouse patrons could take a final wash before entering ‘to dress. This helped to keep the place clean and also to keep the sand out of the patrons’ clothes. The cement pool is supplied with plenty of fresh water, and means are provided to keep the sand cleared from the bottom. All of the stairs leading into this modern bathhouse have a pool at the bottom. This arrangement insures a clean bath- house, free from the annoyance caused by the presence of sand on the floor and else- where. People leaving the place do not suffer from sand in their shoes, as is gen- erally the case. It’s a Water-Escape Ladder Provided for Deer N operator at the power house of the Hetch-Hetchy water supply, in California had an op- portunity not ordinarily afforded a photographer. He had his camera ready just at the right moment to catch a deer climbing up the ladder installed across the aque- duct which carries the water to the intake power house. Sure of his footing, the animal made his way carefully up’ the narrow boards, instinct preventing him from making the graceful leap that one might expect of a sur- prised deer. This ladder is placed in position so:that the deer: that come to drink and. by accident fall into the water, can escape. Strug- gling. in the water, the animal soon finds that he can climb up on the steps.

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December, 1920 The Barracuda and the Blimp We sit on board a ship and fish blindly for hours? Perhaps there are some fish in your vicinity and perhaps there are not. Ina blimp, however, you are able to see into the water and you can spot a school of fish without any trouble. Above you see some men blimp-fishing in San Pedro harbor, near San Diego, California. They were sailing at a height of forty feet when they sighted a school of barracuda. They stopped the engine, let the blimp drift, and, as fast as they could, hauled in the fish. American Rivalry in Dyes }YEN in the matter of dyes, American manufacturers are cutting in on Ger- man monopolies. Phthalic anhydride, an important dye intermediate, is now made in America by a new process which enables manufacturers to sell it for forty-five cents a pound; Germany charges seven dollars 2 pound. Atmospheric air is used in making phthalic anhydride from naphthalene in our country; but the German method ne- cessitates the use of sulphuric -acid and mercury. Bottle-Caps Do Their Bit T= crown bottle-cap, used by home brewers, has a rough, corrugated edge that will cut into the hardest ice. Nail a bottle-cap to the heel of each shoe, as shown below. When you reach your destination, you pull the cap off. 7 Photograph Yourself in a Mirror O outdoors and take your camera. Place a mirror with its back to the sun and stand in front of it. Focus the camera on your image and pull the trigger. You will then have taken a picture of your- self at your best. Of course the camera will show, too. If you-suffer from self-consciousness, no one will ever.guess it when your picture is produced. A Fish-Shaped Padlock peeioees are not exciting things to make, so it is not surprising that an English; locksmith—for the sake . of..va- riety—-made.a-padlock in the shape of a fish,-'-The--keyhole- is ‘located- just below ‘the*ipills,-.and the jaws ;do,.the. locking. When the fish gets lockjaw, nothing will cure it but the proper key. The locksmith who made-the fish bears’ the name Chubb. So he simply copied a real chubb fish to make his lock. Moving-Day for the Mummies HICAGO’S famous Field Museum is changing its locality. Dummies, dino- saurs, butterflies, and sea-dragons were carted away in box cars,. motor-trucks, and wagons. A special track connecting the old museum with the main line of the railroad was constructed so that the heavier articles could be hauled away. Although the moving was carried out in an orderly fashion, it presented a scene that looked like the wildest disorder. Mixed with the animals were Egyptian tombs, mineral collections, birds, - fish, antiques, armor, and statues... Many of the more delicate objects had to be care- fully crated so that no harm. would befall them in transit. Moving-day for a museum costs mkihy thousand dollars. Imagine the surprise of a trainload of cows -should they cross the path of ‘some - wonderful Greek statues or prehistoric creatures. Seeing Little Things of the Sea SOME parts of the bottom. of the sea are very beautiful, as j. the picture below will tell you. This, picture represents .a small section of a sea model’ that has’ been: constructed in the American Museum. of Natural His- tory, New York. The model, wonderfully. made of blown glass and wax, is fifteen thousand times as large as the original small section from which it was constructed. It is known as the Bryozoan Group because of the tiny sea mats and mosses which it depicts. —

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sane baci teleatina tual =o spe ve em ee, gree ae = ene ge FT TL a eal =o aS Seer vate a paeueney ecae~ seep sta Tolakcalaeninmcstilanitl, ita Soin tine ee spe niente tani -_ Snr eT tig Mie api espns ee oxen 5 ane Ae ube - Straining Sewage before It Enters the River P-TO-DATE cities are careful about their sewage systems. They do not let sewage pipes empty directly into the rivers—at least not in Germany. The city of Dresden has a system by which the sewage water is strained first, so that no particles larger than two milli- meters are allowed to escape. The straining is done by large revolving drums like those above. The sewage water passes over them and all heavy particles are deposited on the faces of the drums. Brushes constantly cross the drums and carry off this residue, which is later shipped to farm lands for fertilizing material. The water goes on its way and is finally pumped into the river. Hinged Sides and Peaked Floor Quicken Car-Unloading pr BEIGE STRAINS promptly unloaded would relieve the congestion in many of our large cities and would increase the number of working hours of the trains themselves. But can the work of unload- ing coal-trains, for instance, be speeded up? Germany has found a way—her coal- trains unload themselves. Each car is- placed over a pit and the side bolts are re- moved. A lever is turned and all four sides flare outward. The coal slides off the peak- shaped floor of the car into the pit below and in a very short time the car is empty. This method requires the labor of one man only, and occupies but three minutes of time, thus releasing a freight-car in short order, . ‘ : Be , ay y : : ‘ . = . ‘ws SS . — We cs: a : eh eee eee ey ee An Electric Lamp that Has Two Bases MANY rooms are equipped with bat. a . single . electric-light socket—bath- rooms and bedrooms, for instance. Thus you are unable to do two electrical things in the room at the same. time. The lady who wishes to curl her hair at night must perform this. unattractive _ operation - in some more unsuitable place than the bath- room or her bedroom. But now there is a double-base electric lamp that will pass on some of the current it gets to another implement. The bases are at opposite ends of the lamp, as shown above. Those heavy lead wires that give the lamp its current enter at one end of the lamp and continue right on through, coming out at the other end. The fila- ment is tapped off from them. There is no tip to this lamp, and so the air had to be exhausted from it by means of a tube concealed in one of the bases. New electrical household appliances are constantly being invented and there are not sockets enough in most houses to accom- modate them all. If you want an all-electric breakfast, you need at least three sockets, and perhaps a light besides. Also in the kitchen or laundry sometimes you would like to conduct several electrical jobs at once. These new lamps will help you out considerably. : 40 -— = * Popular Science Monthly A eT Photo by the Bureau of Markets The. Garbage-Can as a Source of Wealth A MODERN King Midas,- by making use of chemistry, might-amass a huge fortune from’ the waste’ products -of our cities. In Washington, the garbage is collected in demountable wagon-bodies ' and conveyed: by train to the place of disposal. Chemists are studying the value of re- coverable products from garbage, not only fats being recovered, but also-fertilizer. Chicago, in 1918, yielded about 4,000,000 pounds of grease, that sold:for 11.57 cents a pound. The fatty material obtained from the garbage collected in Washington, D. C., was priced at 13.5 cents, and statis- tics from the Food Administration estimate $3,000,000 as the value of grease recover- able from the waste of twenty-four cities. This Gasoline Engine Is Handled by a Chauffeur ° HE locomotive below has neither an engineer nor a fireman; nor does it in- dulge in the use of coal. It contains a six- cylinder two-hundred-horsepower gasoline engine, and is one of many gasoline,coaches used where traffic is light. It can be run by any automobile driver. It is eighty feet long and is divided into four sections. The rear section is for passengers—fifty of them. Next is the baggage-room, then the smoker, and lastly the engine-room. As the wheels rest on smooth tracks, it is possible for the en- gine to attain a speed of thirty miles an hour. Dec at. int riv tre jus in eig he mewmasg © sl a —

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December, 1920 - 7 eee en SP ee A Speed Boat that Looks Like a Whale ELOW the bend in the river is heard the roar of a gasoline engine working at high power. In an instant a curious object leaps into sight, and the fishermen along the river-bank are amazed to see a large boat, that resembles a whale in shape, traveling at great speed, and apparently just skimming the surface of the water. This is a new speed boat, a German invention, capable of making seventy- eight miles an hour. It is equipped with a 200-horsepower engine. The evolution of swift motor-boats has been rapid in the past decade. Only a few years ago a motor-boat capable of making a rate of thirty-five or forty miles an hour was considered a wonder. Now fifty, sixty, and seventy miles are expected of the fastest of these craft. Perhaps it will not be long before we shall see them travel at one hundred miles an hour!: To Keep the Milk from Boiling Over GERMAN inventor has conceived a method for preventing milk from boil- ing over. A metal plate, slightly convex, is placed on the bottom of the pan in which the milk is heated, with the convex side up. A chain, connecting the handle of the con- tainer with the metal] plate, facilitates the removal of the disk. When the milk begins to boil, the plate at the bottom vibrates. If no attention is paid to this signal, the milk will continue to boil, but without boiling over. The metal disk prevents the explosive generation of steam at the hottest spot of the bottom by absorbing part of the heat and distributing it over a larger surface. When steam bubbles form, they seek to escape by raising the disk. After the bubble has escaped, the disk drops to its original position until another bubble is formed. ER : werk: ‘ il w ~ the visible violet. Testing Dyes—A New Job for the Ultra-Violet Light [ID°ES the color of your new’ silk dress endure the test of sunlight? If so, the probability is that the silk was tested for the fastness of its dye before it was put upon the store counter to be sold. Science has discovered that the short light-waves carry the greater part of the energy that is transmitted with light. The vibrations that are too small to be seen are found in the spectrum just beyond These are called the “‘ultra-violet,””’ and they constitute one twentieth of the sun’s energy. They are exceedingly active chemically, as can be shown by taking photographs with this invisible light. But ordinary glass absorbs much of the ultra-violet, so special means must be employed to prevent this absorp- tion if one wishes to make use of the ultra- violet. As the rays are quickly effective in pro- ducing chemical changes of a certain kind, they can be used to determine the lasting - quality of dye colors. A special type of mercury-vapor lamp, which transmits as much as seventy per cent of the radiaticns, has been satisfactor- ily: employed in testing the colors-of:silk: _}f- In a few “minutes it accomplishes results © |) that could otherwise be obtained only by . days or weeks, even months, of exposure of . the silk to sunlight. Only dyes that resist the action of ultra-violet rays should be used in coloring fabrics. 41 Monoplane Wings Support Twelve Men NTERED in the recent’ Gordon- Bennett Aviation Cup Race, in Paris, was a little monoplane whose wings are exceedingly strong. It was the Dayton-Wright entry. It carried a 250-horsepower motor with which a speed of more than two hundred miles an hour was attained. One remarkable feature of this mono- plane is the absence of all struts and wires, thus lessening its resistance to the air. The curve of the wing provides great lifting power. The contestants in the race demonstrated the marvelous speed that can be attained by single- seater machines. These are the “hor- nets” of the air, calculated to dart with incredible speed here and there, harass- ing the enemy in aerial warfare. It is difficult to bring down an or- dinary war-plane traveling at one hun- dred miles’an hour; these ultra-rapid targets will exactly double that difficulty. Illuminating a Line of Type for the Typewriter HIS is a clever idea—very clever. Guess again—you are wrong. It is not simply a‘device with which to copy one line ata time. It is an attachment for such a device that illuminates each line. This attachment does not refiect the light directly into the stenographer’s eyes. Its inventor, Robert M. Searle, of Rochester, knew far too much of the science of light to make such an error as that. It merely illuminates the line, which is seen through a long, thin magnifying- glass. A tubular electric light of special construction sheds its rays on the line to be copied. A ray-filter prevents the harmful red rays from reaching the paper. No matter what the time of day, this lighted line is always on duty. Not only does it relieve eye-strain, but it also increases production. Human beings cannot work faster than their eyes will permit. Better sight, better work.

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i a ca a Popular Science Monthly UT two million eight hundred thousand people on an island, give them houses, subways, surface ears, factories, stores, and all the equipment of a city—but fail to pro- vide a means of reaching these people with the materials with which their factories can work, fail to give them fuel and food—and the vast population of. the isolated island will perish. The means of conveying material, food, and fuel to the citizens of the island- city is of utmost importance. Man- hattan island must be hooked up to the United States, and many plans have been suggested to accomplish this ambitious purpose. The great arteries of circulation, the railroads, extend to the shore across the river, but, with only one exception, they do not bring their trains of freight and passengers directly into Manhat- tan. All the material carried by these outside lines must be transferred and rehandled before it is conveyed across the river to be distributed. This in- volves expense which is reflected in the cost of living. Long Island and Man- hattan are connected by bridges as well as tunnels. Why have we. waited so long before attempting to bridge the Hudson? The Man with the Vision In the city of New York is a man who for thirty years has held a vision so splendid that few have had the im- agination to appreciate it. He is Dr. Gustav Lindenthal, consulting engi- neer. His vision centers in a solution of New York’s transportation problem, one feature of which is the building of a great bridge across the Hudson river. it is an undertaking .which.offers far greater difficulties than were. .en: The main span of this gigantic bridge across the Hudson river will be feet in diameter. The weight of the metal in this bridge will be so Connecting Manhattan Island Gustav Lindenthal’s splendid promises to bring to reality a countered in building any of New York’s present bridges. The Hudson river flows serenely along the western edge of the island of Manhattan. From the north it comes, and the early settlers called it the “North river.”” To build a bridge across it in the vicinity of New York would be a simple matter if the bed- rock bottom of the wide stream were not so deep. To reach the basic under- lying rock the builders would have to bore downward through from 250 to- 350 feet of silt and mud. To build a pier in the middle of the stream would be an impractical task, owing to the great depth to which the construction would have to go before reaching the rock base. Besides, gov- ernment regulations would prohibit an obstruction in an important water- way. A feasible alternative is the construction of two piers, 600 feet high, one on each side of the river, resting there on the easily accessible rock. These piers will carry the cables to support a great span, 3200 feet long and about 200 feet wide, twice the length of the main span of the Brook- lyn bridge. The weight of steel in this bridge would be enormous. In fact, the weight. of the main span of more than half a mile is such that the heav- iest joad crowded upon it isa mere 42 nothing in comparison. Mr. Linden- thal has remarked that the string of heavily loaded trains and vehicles crossing the bridge would be no more, as an addition of weight, than a pro- cession of flies walking along a heavily loaded clothes-line. Railway Tracks on a Double Deck The chief purpose of the bridge is to bring the New Jersey railroads into the heart of Manhattan. Fourteen tracks on a double deck would accomplish this purpose. Eight of the tracks would be used for freight and passenger trains, while six of the tracks would be used for trolley-cars or traction trains. Besides, there would be two broad driveways for motor vehicles and two promenades for foot passengers. The weight of the rails for the tracks on the main span alone would amount to searcely less than 1200 tons, -but this again is insignificant: compared with the weight of the steel girders, trusses, and cables. Four wire cables, encased in non-corrosible envelopes eight feet in diameter, would be re- quired to suspend the massive frame- work of the bridge. The cables sup- porting the Brooklyn bridge are but fifteen inches in diameter. To say that the span of this huge Ponular Science Monthly ee —— Sa es

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Derember. 1920 Décember, 1920 . ree, bridge is eet in length does not convey tl mental picture of it. The Woolworth Building is the world’s tallest building. It is 792 feet in height—a tower of steel encased in masonry and concrete. Stand four of these structures on top of each other, and you can form a vague idea of the massive steelwork required for the construction of the main span of this titanie bridge. Instead of carrying its own weight skyward, this colossal load of metal must be suspended by cables in a horizontal position. The bridge itself is but a factor in the scheme to relieve congested transpor- tation in the port of New York. To complete the chain it will be necessary to connect the bridge terminal at Fifty-ninth street with a terminal at the Battery, the tip end of Manhattan island. This would constitute a belt- line of elevated railroad tracks over which the trains could pass on their way back to New Jersey through a pro- posed tunnel at the Battery. A great central union station is also a part of the plan. Ten thousand cars of freight could be moved over this route every twenty- four hours, and six million motor vehicles. could cross the bridge in a year. The suggested system of financ- ing the whole’ enterprise does away 3200 feet long. It will be supported by: four steel-wire cables in cylinders eight enormous that all the traffic that can be crowded upon it will be negliglble with the United States bridge to span the Hudson vision of thirty long years with the necessity of delaying traffic to collect tolls. Automobiles would have an easy access to Manhattan from New Jersey, and by making use of the present East river bridges would have a direct passage to Long Island. No less than eighteen tunnels under the North river would be re- quired to accommodate the traffic which would pass over this single great bridge, and the cost of that number of tunnels would be at least two thirds greater than the cost of the bridge. A Monument to Our Age The building of a massive structure of steel across the Hudson would be a fitting monument to our Age of Iron. Its completion would mark a new wonder of the world, ranking as an engineering undertaking far above the construction of ‘the Pyramids. Its service would be to the humanity of future generations, though nothing could be more appropriate as a monu- ment to the heroes of the late war. In ancient times bridges were built as monumental structures. Why not have this modern enterprise a “Hudson River Memorial Bridge’? Massive arches of sculptured stone forming the bridge approaches would carry out the idea and visualize the part our coun- 43 ‘ try took in the world war. Hidden within the bridge structure would be the arteries of transportation, reaching from beyond the Palisades and bring- ing into the heart of New York the materials necessary for the life and industry of its millions of inhabitants. What could be more splendid than a “living monument,” rather than one purely ornamental and lacking a vital contribution to humanity? ' But how is the money to be raised for such an enterprise? That is the question which has been the chief con- cern during the thirty years since the idea was realized to be a mechanical possibility. How the Project Is to Be Financed Mr. Lindenthal’s scheme is as unique as it is feasible. It overcomes what he considers to be the greatest obstacle in the way of accomplishing the actual building of the huge sus- pended roadway across the river: “The communities on each side can pay their share in the form of yearly rentals,’ says Mr. Lindenthal; ‘‘so also can the railroads. The respective shares can be adequately determined to cover operation, interest, cost of main- tenance, and taxes.” A separate terminal organization would act as agent and trustee for the Federal Government, while private capital, realizing the advantages to be con- ferred, can be relied upon to come for- ward with the required funds for build- ing, equipping, and operating the vast project. ‘Cooperation between the railroads, the city of New York, and the communities on the New Jersey side, and ‘the Federal ‘Government, will assure this method of bringing to life the vision of thirty years.

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pemerese? 6% a A I soar sens ead pat ce hae on haere eminent ae pevarasn coy seeecenedee siete ar a Na —_ ~ = ana mane ae rs Sse ot 20 ae A a HD POO at oo ~ p-eerenamepatns et ipiapt aot mecmeenmarnnne heaier ein ah er iarhigetie ete epee oem apace NE ee a ae wo | 4 : i Popular Science Monthly Your Four Million Pain Spots How you can locate them by simple tests ET before a blindfolded S man a basin of ice- water; tell him that the water is very hot, and that he must quickly dip his finger-tips in and out. He will actually believe that he has plunged his hand into hot instead of cold water. Place two needles about one-quarter of an inch apart in a piece of cardboard and lightly touch his exposed skin without permitting him to see how it is done. There are spots on his body where he can not tell whether one or both points are being pressed upon his skin. By separating the points, or making them closer, his ability to tell whether one or both points are touch- ing him, will vary through an astonish- ing range. Cold, warmth, touch, and pain, are the four sensations produced by nerves whose ‘“‘receptors’”’ lie in the skin, or just beneath it. Some nerves termin-" ate in bulb-like bodies which differ in form, those of one type being receptors for cold, while those of another type receive the stimulations of warmth, though the sensation of warmth arises from the effect upon the cold bulbs, as well as upon the receptors of warmth. The free nerve ends which do not ter- - minate in these bulbs or masses are those which convey the sensation of pain. The sense of touch is also carried by a separate nerve- By Latimer J. Wilson An instrument like a balance scale is used to measure the amount of pressure required to produce the sensation of pain tips quickly into ice-cold water and as quickly removing them. The free nerve-endings which receive the sensation of pain are distributed widely over the whole body. But there are areas which are more densely “‘spotted”’ with them and where pain is more keenly felt. The pain spots are particularly numerous in the cornea of .the eye—the transparent surface that covers the iris and pupil of the eye. The smallest splinter. of metal or bit of glass that finds its way into this covering produces the greatest pain. Comparisons in Body Sensitivity Measured in numbers by which comparisons can be made we might say that the top of your head is about eight times more sensitive to pain than the back of your body. Numerical “weights’”’ rate the forehead’s sensitiv- ity to pain as 1.3; the right temple, 1.0; left -temple, 1.3; right -thigh toward the abdo- men’s surface, 4.3; left hand, palm side, 6.2; right heel, on the side of the sole, 7.0; and the back, 8. Thickness of skin and the extent. of the sub-cutaneous tissues largely determine these differences. But the left side of the body is gen- erally more sensitive to pain than the right. Special instruments have been de- vised for finding out the spots of touch and those of pain. Electrical methods have also been used for this purpose, but the results obtained by electrical means do not agree with those of * mechanical methods. One of the simplest ‘‘pain-finders”’ is a small scale-like device by which weights can be added to press a sharp point into the skin. Difficulty has been encountered in making the sub- ject discern the difference between mere discomfort and actual pain. The pain threshold, that wavering uncertainty which barely marks the merging of consciousness into pain, in- creases in definite realization in curi- ous proportion to the area of the skin exposed to the stimulation of pressure. Thus an instrument which affects a minute area of the palm of the hand and which produces consciousness of pain with a small weight, would with nearly five times that weight affect similarly an area twenty-seven ending. ‘The nerve-endings are distrib- uted over the whole body in mi- croscopic dots, forming little groups in a given area. It is es- timated that there are between two million and four million pain spots on the body, while there are five hundred thousand spots of cold: and an equal number of touch spots. There are only thirty thousand warm spots, and since one depends upon them for the sensation of exterior warmth, he must stand close to the fire on a cold day. Cold Spots Predominate The five hundred thousand cold spots also respond to the stimulus of warmth, but their response is that of cold and not warmth. This curious fact may times as large. Variance in Sensitivity The tips of the fingers are par- ticularly sensitive to touch, but the degree of sensitivity varies considerably in different people. A man whose hands are rough and whose finger-tips are thick, feels touch less keenly than a pianist. Fingering the strings of a violin tends to make the tips of the violinist’s left hand less sen- sitive than are the hands of a musician who plays an organ or a piano. Each finger differs in sensitiv- ity, and there is often a consider- - gers of each hand. On the inside of the cheek little pain can be felt because of the lack of the nerve- fiber endings. Spots of cold are explain the confusion which often arises in attempting: to distin- guish between hot and cold, par- ticularly when dipping the ‘finger- e+ Touch the skin of the forearm with one or both prongs of a hairpin and see if the person can tell whether one or both is ~used, - Pressure ‘on a hair is strongly felt — 44- particularly numerous on the inner surface of the eyelids, on the white of the eye, and on the forehead. These spots quickly -— om of able difference between the fin-. te | nt — > na ara tee Bara

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December, 1920 respond to the sensation of falling temperature. The hairs on the body might be compared with levers exerting pressure on the skin, thus increasing its sensi- tiveness to touch. Lightly press the: tip of one finger upon a clear space on the forearm, then barely touch a hair rear this spot and note the difference. The single hair irritates a smaller area than the finger-tip and thus a lesser pressure is required to stimulate the end of the nerve. A touch is so keen that the points may be barely separated to be felt sepa- rately. In others, the points will have to be very wide apart to be distin- guished as two separate centers of pres- sure. The results differ.in individuals, and the tests are used in psychological experiments, especially in criminology. A sudden increase in. temperature causes pain, while the same degree of heat if gradually attained causes no pain. It is just the opposite with pain from pressure. The sudden impact of a bullet deadens the sensations and no pain is felt; while the gradual pres- sure of a knife causes pain. Emotion Deadens Pain A nervous impulse of emotional character also deadens the sensa- tions of pain and this explains why one may receive a wound during light pressure with a needle-point is more effective than the pressure exerted by the end of a match, because the latter affects a larger area. Some of the Experiments -In this connection it is interest- ing to consider the experiments . which have been conducted with the aid of instruments to deter- mine the curious effect known as “dual cutaneous sensitivity.” Two fine points, two needles in a cardboard support, or the fine points of a small hairpin spread about one-quarter of an inch apart, serve to demonstrate the effect. When these points are gently pressed upon the skin of the arm, forehead, finger-tips, or back of a person who cannot see emotional conflict without know- ing it. Such a condition is ac- counted for by the fact that the nerve-ends receive the stimula- tion, but the nervous impulses do not reach the seat of the nerve to convey a conscious condition. This is illustrated by lack of sen- bility to pain during hysteria. Why is it that persons some- - times feel pain in an amputated hand or foot? Such are called “propagated” pains. They orig- inate in the trunk of the nerve, but are felt in the nerve ends. Some pains are associated with parts of the body to which they may not be accredited. This is due to a transposition of the “nervous impulse,” and can be illustrated by ‘‘pain in the knee caused by toothache,” or pains in the head from intestinal trouble. In this case the false effect is due them, he may not be able to dis- tinguish whether one or both of the points are used. In some places the sense of The back is less sensitive than the forearm or the forehead. It is often difficult to detect the ‘im- pression of one prong of the hairpin from that of both prongs unless they are wide apart to an excitation of the brain areas that are aroused usually only from the sensations received at the ends of certain nerves. Why Aren’t We Killed by Hailstones? HE hailstones shown in the accom- panying photograph did not break any records, and neither, so far as we can learn, did they break any heads. This leads us to propound a question that has fretted us for many a year: Why don’t these aerial bullets kill people? One answer, of course, is that they do. We have searched the literature of meteorology, and we find that Sir John Eliot, late director of the Meteorological Service of India, once published descriptions of all the hail- storms recorded for a long period of years in that coun- try, which seems to be more subject to severe visitations of this character than any — other part of the world. In about half a dozen of these Indian storms human be- ings were killed by hail. In one case, in the Moradabad district, May 1, 1888, it is said that 250 persons thus perished. But such occur- rences are, apparently, almost peculiar to India, and very rare even. there. There is only one record of death by hail in Europe. We do not know of any in the United States. The velocity attained by a falling hailstone can be gaged by the fact that, even when falling obliquely, hailstones have been known to pierce a pane of glass with a clear, round hole, like a bullet-hole, leaving the rest of the pane intact. They have also been found imbedded in the soil of a mea- Hailstones that fell at Lake Minnetonka, Minnesota. Some of the stones were fifteen inches in circumference; some looked like clusters of crystals; some like round, smooth balls. Most of them were shaped like a tomato 45 dow to a depth of a foot and a half. A severe hailstorm that prevailed in Maryland, June 22, 1915, was remark- able not only for the fact that the newspaper reports considerably under- stated the size of the stones, very many of which were actually as big as a baseball or an orange, but also because —again the mystery!—nobody was killed or badly hurt. Describing the storm as it prevailed at Annapolis, Dr. O. L. Fassig, of the United States Weather Bureau, wrote in the Monih- ly Weather Review: “It is rather remarkable that such a shower of stones lasting from fifteen to twenty minutes and passing over a city with a popula- tion of approximately ten thousand, should have caused so little personal injury. The writer heard of only two men who received scalp wounds of sufficient severity to require hospital treatment.” More than “‘rather’’ re- markable, we should say; it requires elucidation.

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erring names gersen ie wessirrenee~ | eond-—peaamaense etree SATS SISA AION SEO 9S 37 i porerend eerie Somteaseneaeied seer entartemmreemnineenternites = Popular Science Monthly Killing a Bear with Electricity An adventure that might have been disastrous but for quick thinking T was a small ] power plant hidden away in the foothills of the western range of the Rockies. Three men ran the plant, Edwin Green, Robert Egerton, and William O’Day. O’Day was away repairing the line. Egerton had gone to a town six miles away for fresh supplies, leaving Green alone. It was a lone- some place. Yet so little was there to fear that there was not a car- tridge in the house at thetime,though Egerton was to bring some back with him. There was nothing to . steal, and as for wild animals— nothing bigger than a rabbit had been seen in the neighborhood for three months. Everything about the plant was running as bars. smoothly as clock- work. Green took out a book and sat down by an open window to read. It was the first warm day since a hard winter. Suddenly the air became warmer, and Green heard slow, heavy breathing. Outside the Window “Even to this day,’’ says Green, “I have wondered why, after I distinctly perceived this, I waited nearly a full. minute before looking up. Perhans I was so interested in my book that I imagined it was the horse I was reading about that was breathing so close to my face. But, whatever I imagined, my thoughts suddenly changed when I looked up and saw a huge grizzly bear standing outside the window, not two feet away, with his head pointing directly at me. “Fortunately—very fortunately fo me—the windows were barred and the door was closed; but I was so taken by surprise that it took me a few min- By C. B. Horsley The bear roared, coming down with his front feet on the iron There was silence as every muscle tautened, then the bear fell in a lifeless heap utes to realize that I was not in im- mediate danger. The bars were extra heavy and the door was also heavy, with a strong latch on it. When I realized that I was safe, I began to laugh at my fright, for I had knocked over several chairs and a table in my hurry to get away. The bear, however, did not go, as I at first expected he would, but began walking up and down in front of the building. He even put his front feet up to the bars of the window in his attempts to get in.” The affair now took on amore serious aspect—that of a siege; es- pecially since the bear seemed greatly infuriated when Green tried to frighten him away by throwing things at him or by making a noise. ‘At the end of an hour the bear seemed as little inclined to leave as Green was to go out and make him. Green began to get worried. Egerton was due back very soon, and he carried no gun. Moreover, he 46 would come by the back of the house and would not be able to see the bear until he was practically upon it. Some- thing must be done. There was no way for Green to warn him, since there was no opening or win- dow of any kind in the back part of the house. As the time approached for Egerton’s return, Green’s anxiety increased. He searched frantic- ally for some kind of weapon’ _ that would kill the bear, which was striding restlessly up and down out- side the window. He could not take a chance on any- thing that would merely wound the animal, for in that case it would be doubly dangerous to anybody within its reach. Finally Green decided on a plan. Although the house was built of brick and concrete, the bars of the windows were entirely embedded in wood. This would serve very well as an insulator. He connected one wire, leading from a terminal of one of the transformers, with the bars of the win- dow, and the other wire he grounded. The End of the Adventure The next time the bear came in front of the window, Green seized a bam- boo fishing-pole and started poking him with it. This maddened the animal to a fury. He let out a roar, and, rising up on his hind legs, came down with both of his front feet against the iron bars. There was not a sound, not a whimper. Every muscle in the bear’s body went tense for a fraction of a second. Then he relaxed and fell limp to the ground. Such a terrific electric current was too much for any grizzly to endure.

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December, 1920

Propelling an Airplane by Kicking the Air How Meélot would use blasts of burnt gas and air VIATION engines utilize at most thirty per cent of the fuel value, and at low airplane speeds the pro- peller screw and the engine jointly drop to twenty-five per cent of their maximum _ effi- ciency. There is there- fore left only seven and one-half per cent of effi- ciency for the condi- tions which are normal for getaway and uncom- mon for landing, the two most important and ticklish phases in the operation of an airplane. To have useful power left for this condition, as well as for maximum speeds, large engines must be used, and, as. they must be at the same time of little weight, they are delicate

* Air and finels are.shot <gdtaliuositly sisider high compression, By Marius C. Krarup COMPRESSED AIR in proportions regulated by_a needle-valve;.into a fireproof FIRE- PROOF r | LINING eae = LP MIXING AND FUEL ~% = L_! IGNITION CHAMBER

‘combustion chamber. . way it is s fired by. a spark: plug, to ‘ start the engine eT ceiving motion from the latter. This is repeated with increasing expan- sion and diminishing ve- locity at each of the fol- lowing cones. In the last one, which is much the largest, the whole mix- ture of gas and air finally leaves the apparatus with such thrust and reaction as may be accomplished by this method. - In this mechanism sev- eral points are of special interest: Thesmall bore of the blast-pipe in the combustion chamber must cause a very high * back-pressure in the lat- ‘ter, and this may operate on the continuously fed - fuel and air as compres- sion of the explosive charge operates in an or- icdinary° automobile en-

and need constant and ; expensive attention to. keep . toe, ins reasonably safe working order. . At the recent Aeronautical Show i ‘in Paris, a propulsion engine, developed * by F. Melot, was the most. radical. exhibit. Melot’s idea is intended to get away from the enormous, waste

“leaying the: ‘engine, impinge’ “against. _its <own. vanishing. wake: with ° small: resistance: ~ “To have ‘the blast. oietate asaj piercing the atmosphere al aS projec jog is the one _ tk

and risk in operation of aircraft which\ ; used’ present methods involve. . . According to Meélot’s plan, ihere is provided a simple engine, ‘which, by continuous combustion of any liquid fuel, or even powdered coal, produces a blast of burnt gas and hurls it against the atmosphere to the rear with such high velocity and peculiar motion that the atmosphere cannot get out of the way very fast, wherefore the struc- ture in which the blast engine is mounted goes forward instead, by re- action from the resistance met in the atmosphere. Producing Atmospheric Resistance The important part is to make the blast whirl and spread before it leaves the engine in the most suitable manner for producing atmospheric resistance, and while very little is known on this point as yet, it is probable that not only must the blast have high velocity, but it must also be made to whirl around a partial vacuum along its axis (as a tornado is believed to do), into which partial vacuum of conical shape the atmosphere will be continu- ously forced from behind by atmos- pheric pressure. On any other sup- Position the jet or blast would, on

resistance met The mass and t dae 0 therefore of secondary i ciding results only when the other factors mentioned are equal. In all previous experience with jets of gas, air, or steam, the results have been poor, because those other factors were wholly neglected. The Melot propul- sion is only a first step in the better direction. Air and fuel are shot continuously under high compression and in pro- portions regulated by a needle-valve into a fireproof combustion chamber. Here it is fired by a spark-plug, to start the engine. The exhaust passes out of it by a small blast-pipe or nozzle, which projects freely toward the mid- dle of the first of a series of conical ex- pansion tubes, and there discharges a thin stream, equal to the muzzle. ve- locity of rifles. The conical tubes are shaped and spaced as shown. Owing to the blast velocity and the hot gas expansion, air is siphoned into the forwardly flaring mouth ofthe first cone, aided by the forward move- ment of the machine, and mixes’ its volume with that of the jet while re- 47

| dogs. not * fall ; second, eq

_ “gine. This may be vital a2) “for efficiency. On the . other andl to feed air and fuel against “thepressurein the combustion chamber must. require a special engine for this urpose:: How much reaction of value or the: propulsion can be derived di- setly fromé the emission of the jet is one of ‘the knotty questions. If: “the® ‘initial velocity of the jet below 1100 feet a fal-to that of sound waves, in the large expansion tube, there is, according to other experiments, a likelihood of wave motions and strong reactions. Better at Low Speeds? It is stated that the trial machine which was exhibited in Paris devel- oped 30 horsepower, at a relative speed in the atmosphere of 164 feet a sec- ond (about 107% miles an hour) and produced a propulsion thrust of 100 ‘pounds. But these figures are meager and give practically no information on the important question of how the thrusts are affected by speed. From the nature of the machine it seems likely that it would operate much better at low than at high speeds. If the figures were thorough. 7 favorable, more of them would have been given, The high relative speed of 10714 m.p.h. may have been determined by wind- tunnel or laboratory tests. The thrust of 100 pounds figures out 30 horse- power, however, at this speed. The weight of: the ‘machine is given as 1.1 pound per brake horsepower. It. is about 5 feet long. ©

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peas nape - vapee spire sasan eo reeatree st proms Le an alae a a rare i Popular Science Monthly “The Earth Trembled; the Heavens Dropped” Showing what is behind those realistic noises we hear in the theater No theater is complete without a wind-making machine. Here you see two of them, which register wind near, far, coming, and going, as well as whistling and howling Crash! A great tree falls in the’ --- A shot’is heard in the distance. The blow of a rattan rod on a leather cushion was what you really heard before they brought the hero in ‘on a_ stretcher distance. The real crash-was the knocking of wooden slats against - a block. As the man turns the handle the slats. strike the block os. You’d never suspect dried peas " of having theatrical aspirations; ~ : yet they have. “This: great‘ wheel is. filled with’ them.* -When the handle - is , turned, - they, rattle against a screen and sound like rain She makes a noise like a horse. ~ When the hero gallops away, she stand; behind the scenes and registers beating. hoofs by means of .a pair of horseshoes mounted on wooden blocks Sheepskin may be used for dignified diplomas, or ittmay: °° be used as a thunder-maker. ‘The skin is stretched over a square oak frame and attendants pound on it ao yi 438 Popular Seience Monthly

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December, 1920 And the law allows you to use them if you don’t show any after effects ‘ If you tell a little boy not to get his feet wet, he'll run for the nearest puddle. Grown-ups are just-the same: ; many .people who never drank beer ‘ and wine now do a rushing brewery business in their own kitchens Homemade Kicks beer came to life—and so did he i H : 4 Snuff is in vogue once more. If you chew some until it becomes a soft paste, and keep it under your lip, you will soon feel as you did when you drank wine like water December, 1920 ‘A glass of near-beer—that’s what the man above ordered. And when he got it, he poured twenty-five drops of tabasco sauce into it. The That bottle of lemon extract has unlimited possibilities. Empty it out, except for a teaspoonful, and then fill it up with near- beer. See if you don’t get a shock Wines may be made at home, provided they are kickless. Here’s a recipe: boil ten pounds of ripe dates forty-eight hours, put the juice in jars, and bury the jars for twelve days. Then see what happens 49 If you run-apples through a chopper, strain the juice, let it stand till it ferments, and then drink it, you will suffer more pleasure than pain. It’s against the law

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werner in ens wee OE IT SIN AE Ta a ee abana be ap a er fod me con Ne OS A NL AT EEE PAREN Ro RA TRAE Neary I ON eter lip eat ate IS Lo Popular Seience Monthly She’s a Brute for Strength UST think of eighteen straining horses in a row, and you will get some idea of the power carried by this boat. It is the Maple Leaf, one of the English contestants in the recent inter- national motor-boat races. Although this boat carried four en- gines, it lost the race. Miss America, with her two engines, was an easy win- ner. Engine trouble prevented the Maple Leaf from winning the race. Four engines are all right when they are running, but they are worse than only two when they yo wrong. It isa case of more engines, more trouble. Miss America gave very little trouble, while the larger boat needed attention. Electricity Stuccos the Walls ODERN §sstucco-workers_ discard the old method of laboriously put- ting on the stucco by hand. They make use of a recently devised ma- chine, that weighs only thirty pounds, but that has a capable motor, and that can be connected with any light-socket. It puts the stucco on a wall at the rate of one and one half square yards, one quarter inch thick, in one minute! Not only is it a useful device for build- ers, but it serves as a life-saver in mines, where the rough surface is made more safe by a protective coating applied with the machine. This machine also stops leaks in mine- shafts and air courses. A Scrap-Bucket in the Floor bm floor-sweeper in this machine-shop has an easy job. When he sweeps up the valuable metal scraps left by the bor- ing-mills, lathes, and grinders, he does not have to stoop to scoop them up. He sweeps them directly into this huge bucket, which is placed in the shop floor. When the bucket is full, along comes a crane, picks it up, and takes it to the scrap-metal car, where it is dumped. Such a bucket effects a great saving in shops where several carloads of metal scraps are salvaged every week. A very heavy cover is placed over the bucket when it is in position, its rim flush with the floor, so that the factory trucks may pass over it without doing any injury to either the bucket or the trucks. The bucket is large enough to hold the sweepings of several days before it is necessary to dump it. ‘It has a capacity of several tons. Although very substantial, the bucket is not heavy. 50 The New Baby Crane SMALL crane that can be rolled around a shop to pick up heavy pieces of metal or other objects has recently been invented. It gets its power from a storage bat- tery that it carries around with it. A chain is placed around the object to be moved; then two hook-blocks, attached to the crane by cables, are hooked to the chains. Next the motor is started. Slowly the cables wind around drums and the burden is lifted off the floor. In this way one man can handle weights that would otherwise require many men to manipulate. How to Thaw Frozen Pipes =o of running the risk of set- ting your house afire with a blow- torch when the pipes freeze, it is now pos- sible to thaw them with electric power. Here is a device as simple as an elec- tric iron, which uses just about as much current. By merely attaching it to the frozen section it soon heats the pipe suffi- ciently to start the flow of water. It is possible to thaw out pipes fifteen feet in length. The base of this ‘‘pipe-thawer” is made of cast iron and the cover is of pressed steel. It is easily carried from place to place. Every up-to-date plumber should have this useful article among his equip- \ ment. Dotan Satanane - Bi aatiites

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December, 1920 Don’t Tremble ; This Is Not a Bomb O, this is not a bomb, although it may look like one. It is a protective case used to transport radium. The radium is placed in a hole in the center of a thick lead crucible. Why lead? Because lead does not permit the passage of the radium rays, and in this way the person in charge of the transportation of the substance is protected from injury. Certain of the rays from radium produce a peculiar and dangerous burn, resembling an X-ray burn, which is prac- tically incurable. ~ For the Canoeist—the Gun that Folds Up SHOTGUN would be much easier to carry if it could be folded. And why not fold it? The picture shows one method of doing it. The barrel and stock are hinged together and may be doubled up so that the muzzle rests against the butt-plate. The gun remains in a fixed position, however, unless a side lever is pressed. You will notice at once that the stock of the gun has been hollowed Hark to the Voice of the Thunder God ‘TBE giant. horns arranged around the top of this speaker’s stand have loud- speaking telephone receivers at their small ends. The voice of the speaker below is directed into a special transmitter. From this point it passes through an amplifying apparatus before it reaches the receivers at the top of the stand, where the articula- tion is flung far and wide to the great crowd. : In this way a single speaker can address as many as forty thousand people in a single gathering. The importance of this new device as an aid especially to politi- cians and other orators cannot be over- estimated. Abe Lincoln was satisfied to get upon a stump and address a few hundred people. But times have changed and present-day stump speakers demand huge audiences. A ‘*Wordometer’’ for the Typewriter VERY time you hit the space-bar on a typewriter you have written a word. The little counter shown in the picture below records the number of times you hit the space-bar, and in this way counts the number of words that you write. It is claimed that the little device never makes a mistake. It is just the thing for short-story writers. When they have finished a story, they do not have to go through it labo- riously to count the words—they have the result at their elbow when the last word is written. The “‘wordometer” is not foolproof, however. - If the space-bar is manipulated for paragraphing, it will record the movements as words. This Electric-Light Plug Fills a Great Need AVE you ever tried to put an electric plug in the socket with a small glass shade attached to it? If you-have, you will certainly be able to appreciate the usefulness of this little device which has recently made its ap- pearance on the market. It saves time and temper, and costs only a small amount of money. It is one of those things that have been needed for a long time, but no out. This reduces the weight without weakening the weapon. The gun can be _ instantly swung into position when game is sighted. It was invented by a canoeist who was in the habit of going on long cruises. He had already tried various kinds of shotguns, but had found them all un- wieldy. The one he invented has a_ twenty-four-inch half- octagon-shaped barrel and it shoots a forty-four-caliber shot cartridge with surprising force and accuracy. This new shotgun is entirely practical for small game or for miniature trap-shooting.. The side lever that is used for folding the gun also controls the loading or extracting of shells. one seemed to have the ambition or the inclination to manufac- ture it. It is really an ordinary plug with an extension. It can be used in connection with an elec- tric toaster, iron, motor, heater, or vacuum cleaner. In such cases, it can be attached to the cord after removing the old plug. A few minutes” labor with a jackknife and a small screw- driver will provide you with this time-saver. . Without it, it is oftentimes necessary to remove the light shade before the plug can beinserted. This is not only troublesome, but there seem to be few people who succeed in getting the shade back in its place before they drop and break it. | a, ae

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’ ORR I yn a wae i A YG ENN, el SANS RY fem RS mp a Ne Sa en new ne oe neresructomwersesitners pet Lon tamer tesserae as TY 9 hen emo reenter mnenry m A RII SANTEE RI MIN Te Sapcgaanmnnioyien sed eee a ae oes - Popular Science Monthly Four Legs for the Vacuum Bottle SINCE nothing is to be gained by crying over spilt milk, care should be taken not to spill it at all. But if your milk is in a vacuum bottle, it is very apt to spill. That is why H. C. Downey, of Spring- field, Ohio, has invented a stand for vacuum bottles. The stand is a four- legged metal device which is fastened around a bottle with a leather strap. It can be adjusted to fit bottles of all sizes. Cutting Uniform Slices of Bread a you can slice a loaf of bread so that you don’t end up with a triangular knob, then perhaps you don’t need a _ bread-slicer. But most of us are not ex- pert in the art of cutting bread. It is for the inexpert that Mr. W. H. Garlock, of Seattle, Washington, has ‘invented the _ bréadslicer shown above. It consists of a corrugated wooden base on which the bread stands. A_ metal To drain the bottle, fasten it upside down in the stand. Such a stand as this will also be of ines- timable value to campers, automobile par- ties, and fishermen. Twine that Is Part Paper A HARVESTER will start across a field of wheat and in a short time leave be- hind it a trail of wheat stalks bound neatly in sheaves. It clips them, stacks them, binds them, and drops off the finished - bundles. For the binding process the best quality of twine must be used. Twine that is rough and not sufficiently strong is very apt to hold up the whole job. But the best quality of twine is very expensive to-day and farmers do not like to pay. for it. Now, however, there is a machine for twisting paper into twine. The paper gives it the necessary smoothness without impairing its strength. For this purpose the rougher fibers may be used, and in con- sequence the twine made from it is cheap. Huge Photographs for Movie Backgrounds HEN the fair heroine of a motion- picture looks out of her window in the play that is being screened, she may be looking at a giant photograph instead of at a real scene. It is often less trouble and expense to obtain a photo- graphic enlargement from a small “‘still’’ negative than to travel a distance to get a suitable background, or to have a back- ground painted. Mr. Shipman, of Los Angeles, California, has devised a way to make huge enlarge- ments from small films or plates. His method is not disclosed, but it is very successful, as can be seen by the illustra- tion, which shows a girl standing beside one of the enlarged photographs. A bril- liant source of light is required, unless a very sensitive emulsion is used, in making ordinary enlargements of great size. Where’s the ‘‘Old Man’’? Be hire superintendent’s wanted on the *phone!”’ What’s the best and quickest way to spread this news when the ‘old man”’ has lost himself in the factory? In England signaling by lights is favored; it is more “refined’”’ than the noise system used generally in American factories. In an English factory, when Mr. Smith is wanted, a switch is turned on and a red light glows in all departments of the factory; other men have other colors. The scope of ears, however, is greater than that of eyes. We can hear noises that come in ali directions. If Mr. Smith is _ wanted, why not make a noise: that is different from the general noise of the factory? Give him one ring; Mr. Jones, two rings; and so on. 52 cover fits over the base, and slots in it guide the knife as you cut. By adjusting a stop at the end of the wooden base, you are able to vary the thickness of the slices. The Gun that Shoots Gas PS hreamany up or I’ll shoot!’ You level | your pistol at the astonished burg- lar. But suppose he failed to hold up his hands and made a dash for safety—would you really shoot him? Most people are filled with horror at the thought of killing a human being; they would rather let him escape. And burglars take advantage of this. But now there is a pistol that shoots a suffocating gas instead of a bullet. You aim it at the burglar, pull the trigger, and paralyze him completely for the time being. The gas is held in the handle under high pressure, and, when released by pres- sure on the trigger, will shoot. : The pistol was invented by a French- man named Trousson.

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December, 1920 A Portable Kitchenette WO rooms and kitchenette— you pay dearly for that kitch- enette these days. Why not supply your own? Here is one that comes in the form of a handsome cabinet, adding to the appearance of any dining- room. When you open it—top and front—you find on the top shelf a fireless cooker and two plain cookers, all operated by electric- ity supplied from a regular house- plug. A rheostat enables you to con- trol the amount of heat that goes into the cookers. Making a Tiny Circus MAKING a tiny circus, complete in every detail, is the hobby of Arthur Thorpe, of St. Louis, Missouri. He is shown below in the midst of some minia- ture animal wagons that he has already completed. At present there are sixty of these pieces, but he intends to raise the number to eighty-five before the year 1921 is past. He has made all the necessary tents. Besides the Big Top, there is a horse tent, three dressing-tents, a blacksmith shop, a cookhouse, and a dining-room. The entire circus, from tents to sawdust, is located in a corner of Mr. Thorpe’s back yard. © Kadel and Herbert Germany’s Porcelain Money (GERMAN marks have so depreciated in value that .the silver in them is practically worth more than the coins themselves. ; In consequence of this, the Germans are considering the use of porcelain in future mark-making. A five-, a three-, and a two-mark porcelain coin, submitted to the German government, are shown above. A porcelain factory in Meissen, which formerly manufactured beautiful vases and dinner-sets, has been making porcelain coins. for the city itself, and has also on hand an order for three hundred thousand twenty-pfennig pieces for the railways of Hamburg. This factory is perfectly well equipped to manufacture coins for the entire government. On the Trail of a Drill [DURING the war, the geophone, a listening instrument, made it possible for our men to determine the exact position of German mine-workers. The instrument has been used in coal- mines for locating entombed miners. It can also be used for getting the exact loca- tion of 9 diamond bit when deep holes are drilled. When the bit has reached a depth of a few hundred feet, it is hard to tell whether it is following the exact path laid out for it. By using the geophone, how- ever, it is possible to find all three dimen- sions of a bit with fair precision. - The Hair-Cut Electrical HE barbers’ strike and the subsequent high cost of hair- cutting need not worry you if you can get an electric hair-cutter. No great amount of skill is needed to operate the machine, and your wife could cut your hair for you. Unfortunately, the machine was invented in Germany, and it may be hard to get. Below are some German chil- dren having their-hair clipped in the most up-to-date manner. New York’s Volcano FIRE that had all the earmarks of a voleano was raging recently in New York city. It erupted in some filled-in land near Van Cortlandt Park. Half burned coal and ashes were used as the filler and the accumulated gases under- neath exploded. In spite of heavy rains, the fire continued to burn for weeks, giving off strong sulphur fumes all the time, to the mystification and alarm of passers-by and near-by flat- dwellers. The ‘newly laid sidewalks be- came red-hot and the fences were burned. The bed of coals burning fiercely gave off tremendous heat and made many a man with a coalless cellar very sad.

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B.A Aaa ae Ne Ne Renee rm Pot N NROE ME RN Fake eS A ES RT Sammy Sma : OPE, IDF oenroreeceoneasipeaarnast Popular Science Monthiy © Keystone View Co. Up to Its Tubs in Ice A STOVE almost completely submerged in ice is a strange sight. How would you feel if you visited your summer home in winter and found your stove in such a plight? That was the experience of some people who had a cottage near Old Orchard Beach, Maine. The pipes had burst and the water flooded the entire first floor. Sofa-pillows, pots, pans, and various other household furnishings were caught in the flood and held fast in the ice, which was several feet thick. From the appearance of the tubs, stove, dining-room chair and table in the picture above, the rooms look as if they were arranged for legless occupants. Newspapers from Slot Machines HERE is a certain exclusive suburb which does not approve of newsboys. They’re too noisy, you know—might dis- turb the baby or the cat. So the exclusive residents buy their papers from slot machines placed on various corners. The required number of pennies are dropped into a slot at the side of the particular paper wanted, as is shown below. This action releases a crank and the paper drops through an opening in the bottom. When a paper is sold out, a sign tells you so. If you haven’t the correct change, the ma- chine will make it for you. me etic elena | | | | Combining the Driveway with the Walk ONCE a Los Angeles man bought a new Colonial house with a small garage at the rear. There was neither a driveway ‘leading to the garage nor steps leading to the house entrance. The house was so new that only the lawn in front had been finished. It was up to the owner to finish the job. But labor and building materials were costly, the owner was not a rich man, and he had already spent several thou- sand dollars on the venture. So he developed an entirely new scheme. He built his driveway and sidewalk to- gether, putting a flight of short steps, two and one half feet wide, between the drive- way strips, making the whole a solid piece of cement work. At each side he built a retaining wall to hold the lawn earth in place. At the top of the steps a narrow walk branches off, leading to the front porch of the house. The general scheme is decidedly ef- fective, and the owner says he saved con- siderable money in labor and material by building in combination rather than by putting in a separate driveway and walk. A picture ofthis “driveway with steps in place of the usual grass strip is shown above. 54 Buy a Tree and Save a Forest - D° your share to preserve our forests,”’ says Mr. A. Kraft, of Oakland, Cali- fornia. And then he tells one way to do it —by using the combination Christmas tree, hat-rack, and clothes-rack that he has invented. Just one tree-trunk is needed for all three and it may be used for years. Several small holes are bored init. When you use it as a hat-rack, you put short pegs in these holes. On washday you take the short pegs out, put in long ones, and hang your wet clothes on them. When Christ- mas comes round, you “procure’’ some pine branches from somewhere and fit them in the holes. One tree, only, need be sacrificed for all your household hanging operations. : A Shoe-Shine in Your Vanity Bag FIRST aid to dusty shoes may now be “ found’ in vanity bags. Possessed of such aid, a woman, after crossing a dusty road, presses a button at the side of her vanity bag and out jumps a felt pad at the end of a wire spring. By bend- ing over slightly she is able to brush off her shoes, and proceed on her way re- shined. She compresses the spring of the pad-in-the-box and tucks it out of sight. “‘Where are these dusty roads?” you ask. In England; the invention is an English one. But it will undoubtedly find its way to this country.

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December, 1920 A Little Scent Sweetens All the Air ERE is a deodorizer de- signed to hang on the wall. In it is placed a sweet- smelling volatile liquid that continually evaporates, filling the air of the room with a pleasant odor. The liquid lasts for several days. When it is exhausted, the supply can be replenished from a bottle furnished with the de- odorizer. A stopper placed in the opening will prevent evaporation if the room gets too “‘sweet.” When the housewife is He Made His Own Stop-Watch CE champion C. J. Cooke, of Washington, D. C., wished to time his daily swims in order to see how his speed improved. But nearly every time he swam, there was no one around to hold a stop-watch. He couldn’t very well take it with him, so he invented a clock that would serve his purpose. He took an old alarm- clock, removed the spindle that held the wheel opposite the escapement wheel, and cooking cabbage or when Limburger cheese is on the menu, this device will be more than wel- come. A New-Yorker who uses the sub- ways during the rush hours suggests using deodorizers as a means of making travel more comfortable. Here’s a Duplex Book - A LEVER is shown at A in diagram 7.”’ When you read it, you start looking through the book for diagram 7. It may or it may not be on the same page. How much simpler it would be if diagrams and reading matter were always in front of you at the same time. In the new double book shown below, invented by a German engineer, this is the case. The pictures and diagrams are in a book by themselves. This book, together with the book of reading matter, fold inward and become one when not in use. This Beautiful Arch Is Made of Bamboo Trees HE Botanical Gardens in Rio de Janeiro are the finest in the world. Not only are they very beautiful, but in them there are many strange growths of great interest to scientists. Among these interesting phenomena is a remarkable arch of bamboos. The trees grew so rapidly that they were unable to stand erect and they bent over in the form of an arch. Just beneath this arch of bamboos there is a bubbling brook with a path at its edge. It is a charming spot, and is visited and enjoyed by people from all over the world. — ; There is another famous arch in the Rio de Janeiro gardens. It is formed by two rows of enormous palms that bend toward each other at a height of one hundred feet. put in its place a much longer spindle. The wheel’s revolu- tion speed was thus changed and the minute-hand became a second-hand. He noted the time when he plunged into the water, and again when he came out of it, thus keeping his own time. Chess-Playing by Wireless HESS-PLAYERS aren’t the least bit sociable. If one were in Berlin and the other in The Hague, they could con- duct their game just as well, provided that each knew the other’s moves. By means of a new device, two champion players tried this recently. A piano key- board with white and black notes, repre- senting the squares on the chessboard, was connected with a wireless sending station in each city. By pressing down a key that corresponded with a certain move, a wire- less signal was given, and this was sent on to the player in the other city. € Mirzacff

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Popular Science Monthly } joe —_ 7 aera » es he aa RESISTANCE GRIDS —{, taseny nics, cremate terete ae : A , a = ~ Sens ft ee ‘ ‘ ©; 4 Re NeOr & ate - | a SS A AOR AY ATL TE SERA MS ey. iS BND | { anne encennenenerenecce Sn FORCED DRAFT CONTROLLER FOR HEATER eo ee Se ’ y } Au. noel es i a — ELS _- EERE SL > ~ a * ae S Se ‘ka een ~ Copyright, 1920, by Modern Publishing Co. } Like a trolley-car this huge electric locomotive, which hauls trains over the Cascade and the Rocky mountains on the Chi- cago, Milwaukee & St. Paul Railway, can be controlled from either end. Hence turntables are not required at division points In front of the engineer, at each end, is an “apparatus cab,” filled with resistance coils, through which passes the 3000-volt current, controlled from the engineer’s levers through solenoid switches. The front section, or “apparatus cab,” is closed when the engine is running. If a man were thrown against the coils while the engine is rounding a curve, he might be killed. The central passage accommodates a man, who can make repairs when the locomotive is idle Remar aie anen oh 56 The electric locomotive needs no tender filled with fuel. It can run one thousand miles without overhauling; for there are no ashes to dump, no flues to clean, no boilers to inspect. Its horsepower is about 3500, so that it does the work of four steam locomotives Over the Rockies HE steam-locomotive boilers of the country generate, al! told, 50,000,000 horsepower. One quarter of all the coal mined in the United States is thus consumed. This total horsepower is, just about equal to the water-power that ‘is going to waste. Hence, if water-power were used to operate railways, 150,000,000 tons of coal would be saved annually, and an army of mine and railroad workers would be released for other em- ployment. Despite these well known facts, the electrification oft our rail- roads has been a slow process, due chiefly to the fact that the problem of substituting electricity for steam involves not merely the employment of another kind of locomotive, but the adoption of a fundamentally different method of train propulsion. Railroad electrification has received an enormous impetus now that the Chicago, Milwaukee & St. Paul system has banished steam entirely from its Pacific coast division. The total electri- fied main-line trackage is 700 miles, so that the United States becomes the possessor of the longest electric railway in the world. The road extends from Harlowton, Montana, to the Pacific coast, crossing on its way two mighty mountain ranges, the Rockies and the Cascades. Fifteen water-power stations make available a combined electric horsepower of 410,000, so that, in a sense, you are carried by a waterfall as you travel over the mountains. Electric operation has reduced by twenty-two and one half per cent the number of trains and by twenty-four and one half per cent the average time per train. It has improved operating conditions, so that nearly thirty per cent more tonnage can be handled electrically in eighty per cent of the time formerly needed to handle the lesser tonnage by steam-engines. The capacity of the road has heen thus increased about fifty per cent. Of the locomotives that have made these marvels possible fifty-one were designed and built for the Chicago, Milwaukee & St. Paul railway by the General Electric Company. There are sixty-one of them all told, including passenger, freight, and switching engines. They have released for service no

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December, 1920 POUICK-ACTING CIRCUIT BREAKER MAIN CIRCUIT Mi Mi, Ce AOA (Ee Ba 2, OR gm eee ee Re Oe Ce ee SS REVERSE 7 MAIN CONTROL CIRCUIT ee een eee ee ee eee eee ee Ee eee ee ee gee ee we oe It hauls a 960-ton, twelve-car passenger-train on a two per The over-all length of the locomotive is 76 feet, its total weight cent. grade at twenty-five miles an hour; the steam locomotive 260 toris. Between the leading 3-axle trucks at each end are would make only twelve miles. On the level, the electrically two 8-wheel driving-trucks. The train hauled by the locomotive hauled train makes an average speed of sixty miles an hour is heated not electrically but by steam from an oil-fired boiler on a Waterfall fewer than 162 steam-engines and have effected an annual sav- ite ing of 300,000 tons of coal and of 40,000,000 gallons of fuel oil. ee its, HEADLIGHT The electric locomotive takes its current from an overhead as. wire like a trolley-car, not with the usual pole and wheel, but with an ingenious double trolley, called a “pantograph” after the drafting instrument of the same name. The pantograph always insures perfect contact. The locomotive never “gets off the trolley.” Current at 3000 volts—the highest direct-current voltage em- ployed in railway work anywhere—is taken from an overhead wire. But the huge electric locomotive must not be regarded as a magnified trolley-car. It embodies so many new ideas, both L - in railroading and electrical engineering, that it marks a new epoch in transportation and in locomotive building. The low-tension currents used on a street-car (600 volts) can be handled directly by the ‘‘controller’ of the motorman. But in the case of this 3000-volt current the controller in the engi- neer’s compartment operates certain ‘‘banks’’ of electromagnetic switches (solenoid switches), and these in turn feed the current to the motors. The electric locomotive returns power on the down grades. The speed slackens. The motors (not the brakes—for they are not needed) assert their control. The grade becomes steeper. As the engineer scans the dial before him, he sees the trembling pointer slawly reverse its motion—creep, point by point, in the opposite direction. The motors, now converted into generators, are giving back current to the power line! The air-brakes are used only to stop the train at stations and in emergencies. “Regenerative braking,” as it is called, is not electric braking. From the overhead wire the electric current passes to the It is electric speed control. The motors on the down grade pro- engineer’s control levers. A glimpse of the interior seems duce an electric current when the armatures are revolved, and bewildering, with its ammeters, gages, and speed-indi- the recovered current is restored either to the railway’s power yor Big on yas with the devices required to — line or to the power company’s transmission line. In the latter na codliean sediaeane to bag eas se Boveniy m pla case, the restored current automatically sets back the power plexity. Yet, to the engineer who presides over the “ sole- company’s meters and credits the railway with the amount of the noid switches,” through which the current is relayed to the regenerated current. Electricity keeps its own books! motors, all this is like reading a thermometer aia §«=6S eee

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Popular Science Monthly Rocking Wings for the Airplane NSTEAD of traveling around the earth in eighty days, it will be pos- sible soon to make the trip in eighty hours if airplanes are built according to the latest discovery. The practical result of the discovery that F. Handley Page has made by means of wind- tunnel experiments concerns the “‘aero- foils,”’ the wings and air-surfaces of the machine, showing that these can be driven through the air more than twice as easily as heretofore with only one third the horsepower. An albatross will soar along behind a ship for days, hardly ever flapping its wings. How it manages to find sup- port in seemingly still air and keep up its gliding flight is an unsolved secret that the Association Fran- caise Aeérienne is assidu- ously trying to discover. In the Early Days The Wright brothers per- formed their first glides at Kitty Hawk, North Caro- lina, in a stiff breeze that was blowing up their in- clined surfaces—a veritable sliding downhill on the air. Finally they made a motor sufficiently light and power- ful to push the machine fast enough against the wind to keep it in the air and at the same time drive it forward over the ground. Instead of sliding downhill and gradually losing elevation, as it did when gravity was propelling it, the method of flight was reversed and the planes or wings (aerofoils)—set at an angle of seven or eight degrees—tended to run up an incline on the air. As this inclined plane of air was not solid, it was constantly pushed down as the machine passed over it, and the latter followed a horizontal course. By depressing the tail, the angle of the wings became greater, causing the lift to increase and the machine to ascend an inclined plane of air. The power of the motor is exerted through the propellers to overcome the ‘head resistance, or “‘drift,’’ of the ma- chine and its wings, and hence to push or pull it forward against the wind. When the angle of the wings with the horizontal is reduced, the head re- sistance becomes less and the machine fiies faster. In starting and alighting, an angle of ten degrees or so develops a great lift as well as big head resist- ance, and causes the machine to take By Stanley Yale Beach off quickly on the one hand, or to land at a low speed and soon come to a stop on the other. When in flight, by reducing the angle to two or three degrees, the drift drops off and the speed increases rapidly. Instead of the power required to drive increasing as the square of the speed, the latter may be very appreciably increased with the same horsepower. This may be one solution of the Handley Page discovery. At any rate, its value has been demonstrated by the airplane of George Lanzius, of New York, who built during the war several machines which the United States government failed te use. Equipped e a mI . Wa ? The Lanzius biplane, whose wings rock upon steel tubes passing through their ribs, thus changing the angle at which the wings are directed in flight. High speed can be — with low horsepower when the angle of incidence is sma with a 400-horsepower Liberty motor, a 34-foot-spread biplane of this type took off with a two-degree angle merely in a run of but 500 feet, and kept steadily rising as it traveled faster and faster on a straight course. It covered two and one half miles in thirty-five seconds. This without using the in- creased angle of incidence to start. Varying the Angle of the Planes By an ingenious arrangement, the angle of the planes of the Lanzius machine may be easily varied in flight. It may be reduced to zero degrees, and even be made slightly nega- tive. In this way the head resistance may be progressively reduced and the speed increased. With higher speed, less area of supporting surface is required in the wings. There have been a number of schemes to reduce the area in flight, 58 9 == Yea steel frame of the Lan- zius biplane. The wings turn slightly about the long and short steel tubes upon which they are mounted at the center of pressure but none have been operated success- fully to date, so far as the writer knows. Professor Langley always maintained that the law of the square of the speed did not hold, and that the higher the speed and less the angle, the less the horsepower required, or that with the same horse- power one could fly at tremendous speeds. Other Experiments Henry A. House, who per- formed the Maxim experi- ments in England twenty- four years ago, agrees with him, and maintains that if a plane falling to earth from a great height de- velops a speed of three hun- dred miles an hour or more under the pull of gravity, it is also possible to make it do this horizontally when pulled by a propeller. The latter will have to be of the variable-pitch type to cause it to pull constantly at continually increasing speed, but by seeking high altitudes where the air is lighter—at 33,000 feet it is about one half the density—the head resistance is so cut down that extremely high speeds are possible. Experiment has shown that the shape of the engine is highly important as regards head resistance, as is also the proper pointing and streamlining of the nose of the body. For great ele- vations an airtight body resembling a submarine will be used, in which the pressure will be kept at atmospheric. This will contain the engines as well as the people. Mr. Lanzius has designed such a craft with many sets of his variable- angle planes on each side. It is a veritable air leviathan, capable of flying around the earth in eighty hours instead of in the eighty days required by Jules Verne.

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December, 1920 Thirteen Billion Suns— Living and Dead How astronomers measure the universe By Abbé Théodore Moreux Director of the Observatory of Bourges, France lying plan of distribution. When You Look at the Stars From the days of the ancient Chaldeans, astronomers have wondered not only how many stars there are, but what is the under- Abbé Moreux takes up these two questions in this article. He is not only a practical astronomer (he is the director of the Observa- tory of Bourges, in France), but he is cone of the great French popularizers of science. OOK at the sky on a moonless night. There arches the Milky Way, a broad, phosphorescent ribbon that encircles the whole sky. In the telescope it appears as an ac- cumulation of stars that defies our imagination. But, even with the naked eye, it is easy to distinguish what seems to have escaped the ancients— that the number of stars in the heavens increases aS we approach the Milky Way. Sir William Herschel, the first astronomer to make use of truly powerful telescopes, cap- able of grasping the light of the _ fainter stars, found the Milky Way literally composed of clouds of stars. He wondered what might be the sun’s relation to such a vast assemblage of stars. He believed that we were placed in the*middle of a uni- verse shaped like a disk. Through the effect of perspec- tive, these stars in the disk appear to be in greater number if we observe them diamet- rically across the plane of the disk. As our eyes turn in a direction away from the plane, the stars diminish in number. The whole seem- ingly fantastic conglomera- tion is what we call the uni- verse, and it is composed of about one bil- lion stars, all suns like ours, stage of evolution that is more or less advanced. In addition to the stars that seem to crowd around the plane of the Milky Way, telescopes show other objects no less interesting. Globular swarms of stars and strange, misty shapes which we call nebulae are also found near the plane of the galaxy. Do they form part of our universe? That question Sir William Herschel decided that this was the shape of the universe, the sun occupying a place in the great assemblage of stars A chart showing the distribution of stars, clusters, thank f th ‘ and nebulae in the universe. The large dots remote e plane of the and all in a from the Milky Way represent the spiral nebulae galaxy. 59 The astronomer Proctor placed the sun in the center of the great galactic circle confronted scientists for more than two centuries—and still confronts them. At the time of Herschel, nebulae, like star clusters, were considered too distant to be defined into separate points by the existing telescopes. Both were thought to be masses of stars like the Milky Way. As telescopic power was increased, many of these misty ob- jects were seen to be composed of myriads of stars, and this led to the conclusion that perhaps all nebulae were thus consti- tuted. Thus originated the fan- tastic theory that these bodies were other universes, or “cosmic islands” in the vast ocean of space. But in 1864 it was discovered that a large number of the so- called nebulae were gaseous bodies, vast masses of material destined to form worlds.. This induced astronomers to adhere to their original theory that the nebulae belonged to our uni- verse. But as the number of these misty patches of light increased as more powerful telescopes were used, it was found that the greater mass of them seemed to be collected at the points of the heavens re- mote from the Milky. Way. Thestellar clus- ters, however, were found in the regions near

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Popular Science Monthly, The Abbe Moreux, Theologian and Scientist Abbé Théodore Moreux, director of the Observatory of Bourges, France, early became interested in the stars. Though he is best known as an astronomer, he is also dis- tinguished as a geologist, a chemist, a mathematician, a physiologist, and a physician. With all this profound knowl- edge, he is yet simple and modest. He was one of the first scientists to conclude that the sun is the great weather-maker of the earth, and that solar disturb- ances are directly connected with the earth’s cataclysms. He predicted the great earthquake that devastated the region 60 about San Francisco, and has since made other important predictions. His early investigations disclosed many strange facts about sunspots, those gigantic disturbances that are known to affect the earth’s magnetism. He tells us that the universe is vastly greater than was imagined by the ancients. ‘““We know,” he says, “‘that among the bright stars are many that are comparatively dark. These semi-extinct suns, in the dark cemetery of space, counted with the estimated number of bright stars, provide a grand total of twelve or thirteen billions of living and dead suns.”

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December, 1920 The relations of the star clusters and nebulae to the Milky Way be- come evident by their distribution in space.. The mystery seemed to clear away when rough estimates showed that some of thenebulae, like that of Andromeda, were nearer to us than the most distant stars. : According to: Simon Newcomb, the eminent American astronomer, the disk in the midst of which we are placed is so enormous that light rays have to travel from ten thou- sand to fourteen thousand years to traverse its diameter, traveling at the rate of 186,000 miles a second!. The spectroscope, an instrument that spreads the light of a bright body into a ribbon of color, was then invented. Not only did it permit— us to analyze the substances that glowed in the stars, but it indicated in which direction the stars were moving in our line of sight. Light, somewhat like sound, travels in ‘“‘waves,”’ or oscillations. When the body emitting the light is coming toward us, the waves are crowded toward the blue end of the spec- trum. When it is going away from us, the waves are drawn out toward the red end. The effect is illus- trated in the approach of a swift automobile when a continuous blast of its horn is sounded. The pitch rapidly rises until the automobile passes, then the pitch falls. The short sound-waves of high pitch correspond to the short blue waves of light. This is called ‘“‘Doppler’s principle.” Measuring the amount of change in the spectrum of a star, its speed of approach or recession can be determined: The ancients considered the stars as “fixed” in space! Their average rate of motion is 22.5 miles a second.. But there are some stars, such as the bright Arcturus, whose motion is: greater than a hundred miles a_ second. The power of attraction of all the stars in our universe would not be sufficient to account for so high a rate of motion. That being so, whence came these stars? If they came from other universes beyond, then the old astronomers must have been right. The nebulae farthest from the Milky Way are of a spiral form, somewhat re- sembling a burning pin- wheel. More than half a million nebulae have been disclosed by photography, and many of these curious masses are traveling through space at a speed equal to that of the stars. This would give new weight / star masses. A rich region. of stars in the Milky Way. Dark rifts stretch across .the glittering background in a singular and perplexing manner to the theory of cosmic islands. Our own galaxy probably resembles these spiral- nebulae as seen from remote _ Tegions.. The sun occupies a place com- NORTH SOUTH Abbé Moreux places the sun near the center of the great In the margin can be seen the constellations through which the galaxy extends in its gigantic circle around the heavens 61 paratively near its center. The speed of our “‘cosmic isle’ is 1040 miles a second! Recently Dr. Shapley, of Mt. Wilson Observatory, has measured the distances of clusters and nebulae, and has shown that these mysterious objects are farther-away than the Milky Way. The nearest star clus- teris at'a distance of 20,000 light: years, and the most distant more than 200,009. From these recent dis- coveries we find” that we must expand by-a vast de- gree our former estimate of the size of the Milky Way, which the astronomers of the nineteenth century had enclosed: in too. tight a circle. According to mod- ern conception, the sidereal universe forms an enormous sphere 300,000 light years in diameter. The poles of this sphere are occupied by the spiral nebulae. The equator is occupied by the disk containing the stars, around which are massed the star clusters—our solar system among them, about 60,000 light years from that gigantic formation.

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Bread without Flour The grain, robbed of its husk, is made directly into dough READ has been the staff of life for thousands of years, as the Bible testifies. But in the passage of cen- turies no one has attempted to change the general process of bread-making. The grain has been ground to flour and the flour has then been turned into dough. This intermediate flour stage is un- necessary, says Mr. Gross, a German scientist, whereupon he brings forth a new and startling bread-making proc- ess which entirely eliminates the flour stage. And what is more, the dough contains the valuable albuminous mat- ter found in the bran without contain- ing the indigestible cellulose husks. Goats are the only animals that can digest cellulose; that’s why they'll eat everything from newspapers to nuts. When a human being eats bread which contains these cellulose husks—and most bread does—he is trying to do as the goats do. He fails to digest them, however, and as a result his system is irritated. And now for the huskless process itself. The grains encased in their thin shells are dropped into a trough con- A special machine cuts the kneaded dough into pieces of uniform weight. Another ma- chine molds them and, when baked, they are all of the same size, a method fol- lowed by most bakeries This is Mr. Gross, the German who invented the new method of handling grain. He spent twenty years working on the process before he perfected it By Dr. Alfred Gradenwitz taining hot water and are given a strenuous shaking for about half an hour. By this time the shells, or husks, have been detached from their grains and are ready for separation. Whereupon the entire contents of the shaking-trough are dumped into a reservoir containing a continuous sup- ply of clear cold water. The heavier grains and albuminous matter drop to the bottom, while the indigestible husks and all impurities float on the surface, forming a dark layer. Compressed air is turned on. It stirs up the husks with such violence that they are carried away by the ever moving water. At the end of ten min- utes they have completely disappeared and the grains can be seen at the bottom of the reservoir through the transparent water. How the Grain Becomes Dough A trapdoor in the bottom is released and the grains drop on a rolling-mill below. They pass over a series of granite rolls and are crushed till they form a fine homogeneous dough, ready to be made into bread. Salt, leaven, and water (if necessary), are added to the dough. But in most cases the grains have absorbed enough water in the husking process to make the addition of water unnecessary. The dough is now ready to be kneaded. This is done by means of the usual mechanical mixers. A special machine cuts the kneaded dough into pieces of the proper weight, and a molding-machine gives them their shape. They are baked in quantity in an electric oven. One man can manage this entire process Popular Science Monthly himself; in fact, one man can take care of a large-sized plant. The loaves of bread made by this method look just like ordinary loaves, as is shown by the picture to the left. But your digestive system will know the difference. It Took Twenty Years to Perfect Mr. Gross, the inventor of this flourless process, spent twenty years working on it before he perfected it, and the results have been even better than he expected. Not only is the bread highly digest- ible, but a greater quantity of it can be made from a certain amount of grain than can be made by the old process. From one hundred pounds of grain one hundred and forty pounds of bread can be made by the Gross process; whereas only one hundred and eight pounds can be produced by the usual grinding process. And the time of dough-making is greatly re- duced. Half an hour after the grain is dumped into the shaking-trough it emerges in the form of dough. This husk - removing machine consists of a shaking-trough and a cleansing reservoir. The trough is filled with hot water and the grains are thrown in shaking loose the husks The huskless grains are crushed through a series of granite rolls (shown here), coming out at the bottom in the form of a fine dough, ready for use Popular Science Monthly

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December, 1920 December, 1920 Sharpening Drills by Machine HIS compressed-air forge is capa- ble of doing the work of several blacksmiths and their helpers. The new machine is largely used in sharpening bits used in rock drilling. A short time ago this work was done by hand. Where large excavations or tunnels were being made, several black- smiths had to be on hand to keep the bits sharp. One man and one machine now sharpen the bits as fast as they are dulled. The hit is heated in the forge and The Paint-Sprayer AINT-GUNS and _ paint-sprayers are constantly being invented, and yet we continue to see the hand painter on the job, complacently drawing his large wages each fair day. Why is it that the sprayers and guns do not flourish more rapidly? One reason is loss of paint; another is the spattering on surfaces not to be painted; and, besides, the paint is apt to get a chalky consistency due to the evap- oration of oils while still in the air. There is, however, a new paint-gun designed to over- come these objections. The nozzle has two openings —a central one for paint and an annular one around it for compressed air, whose pressure is sixty pounds per square inch. This sur- rounding air carries the paint to the surface and is so powerful that the paint can’t break through it. Thus it is neither lost nor spattered. The paint is released in bulk. Hence the oils in it do not dry before they should. placed under the plunger of the com- pressed-air machine. A _ blast of air under high pressure forces the plunger down to reform the business end of the bit. The drill ends can be sharpened with this machine as fast as they are heated in the forge. With one man watching the forge and another feeding the machine, the work of seven or eight black- smiths can be performed. Where extensive excavations are be- ing made, there is always an abun- dant supply of com- pressed air to oper- ate the sharpening machine. This is a com- pressed-air drill- sharpener. By its use two men can do the work of eight black- smiths. It elim- inates the clum- sy old-time forge that Can’t Spatter guards it against wind and dirt, while it also guards the surrounding terri- tory that does not need paint. Even in the heaviest wind this paint- sprayer can be operated successfully. And when there are dirty surfaces to be cleaned, the painter can use the com- pressed-air jet for the purpose. It is obvious that the cap worn by -the girl above is both sanitary and a_ precaution against accident to her long hair This girl’s hair was caught in a machine and pulled out by the roots because she wore no cap while working at her machine Safety Caps Protect Factory Workers ANY of the thousands of women who went into factory work during the war are remaining because of the good wages. One look at the picture above will explain why some form of cap.is neces- sary for every woman factory-worker. The girl in the lower picture did not wear her cap. As a result a handful of her hair was torn out by the roots. If she had worn her cap, she would have saved her hair and - avoided much pain. Yet the usual cap is uncomfortable, hot, makes the hair fall out or turn gray, and causes severe headaches. To overcome these disad- vantages, a self-ventilating cap has been devised. It weighs only one quarter of an ounce and is made from a combination of large and small cotton mesh in- stead of the closely woven material generally used. It is carefully patterned and cut so that it will fit over the head and hair easily and will always keep its shape. This cap may also be laundered, and it is fur- nished in white for candy and food-products fac- tories, bakeries, and the like, where it lends a de- cided air of cleanliness and efficiency; or it may be had The wall of air that com- pletely surrounds the paint / / There are two openings in the nozzle of this paint-sprayer— a central one for paint and an annular one for compressed air 63 in. brown, a_ serviceable shade for machine-shops.

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Popular Science Monthly New Jobs for the Phonograph It whirls other things just as easily as records This man made some wooden candlesticks; when they were stained and ready to be polished, he placed them on the phonograph turntable and held the polishing- brush firmly in his hand = eS —— ss | Lee Sey Place a glass containing a drink on a stand fitting over the center pin. Attach a stationary arm with an ad- justable lever to the phonograph. The lever will stir up the drink as the glass revolves “Help! Help!” shouts the record when a burglar opens the door. A string is tied to the door-knob and the * release lever of the machine. When the door opens, the record yells for help Why pay to have your nails polished when you can shine them yourself without expending any energy? Simply attach a circular buffer to the turntable and pull the starting lever b ee Seal . The cleaning of silverware is always a bugbear to the housewife. By smearing the turntable with polish the phonograph can be used to shine all the knives and forks You can buy plain white dishes and some gold paint. Place each dish on the turntable of your machine and hold the wet brush against the edge when you turn on the power 64

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December, 1920 A four-legged chicken be- comes scientifically inter- esting when examined by the X-rays. This chicken was five hours old when the X-ray picture was made by Cox-Cavendish To See What’s Inside Have an X-ray photograph taken St wa a A radiograph (by the Cox- Cavendish Electrical Company, of London) of a cake of chocolate ‘showing pieces of wire and a staple in it. We hope these were ;mixed in the cake for X-ray purposes and not by accident “Y ape b i) . weg a ie — Nf & ‘ .. ie ‘ $ Poy be . o : 2 - eS a : ; ‘ae y : 3 2 ae, : ~ : = a 4 mae > = % et .. si a . aS SEES: wa X-rays can now be made in a second or two, instead of waiting twenty minutes for their light to affect the photographic plate. Below is an automobile tire with the X-rays shining through it, contributed by the Cox-Cavendish Electrical Company to the Rontgen Society’s recent exhibit in London. The canvas fabric can be seen through the rubber tread Of special interest to botanists were these radiographs of roses, fuchsias, fern leaves, and other leaves, made by Dr. Robert Knox, of London. The application of the rays to plants facilitates the diagnosis and study of plant diseases Here is Dr. W. F. D. Chambers’ X-ray photogtaph of an ammonite. parently consists of a homogeneous~ Although a fossilized ammonite ap- mégs;¢the stays discriminate ‘between the shell -and -the filling material 65 You can have an X-ray picture made of your watch to see what is wrong with it, as this one by Cox-Cavendish shows. X-rays penetrate cvery substance except lead K a el a Radiographs of metals dre im- portant. This picture, made by Cox-Cavendish, is of a weld ina steel bar, showing imperfections in welding. The white marks are air spaces. The rays can penetrate half an inch of steel

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The Card Tells the Price bes order to: keep the customers’ memory informed of the rising cost of milk some dealers are now using a_ clever device. The information is printed on a strip o cardboard in which a hole is cut at one end. When a bottle of milk is left at a house, one of the cards is slipped over the neck of the bottle. The customers have no excuse for claiming that they did not see the notice, for they must remove it from the bottle when they take it into the house. When an Airplane Collides with a House — trying to get into the air after a stop at Omaha, Nebraska, the tall weeds in the field through which a metal airplane was ‘“‘taxi-ing’” acted as a brake. When the machine otherwise would have been high enough in the air to clear all near-by obstructions, a series of telephone wires and a house loomed just ahead. The result is shown in the photograph reproduced below. One wing of the monoplane was dam- aged and its running gear was torn off. Captain ‘“‘Eddie” Rickenbacker, who was one of the passengers, was the only one hurt. He described his injury as a “‘severe fracture of the straw hat.” A Headlight for the Walking-Stick ANY man who walks along a dark country road at night needs both a stick and a flash-lamp. The man who rides in taxicabs or on the top of buses needs a light when he looks for change to pay his fare. Here is a walking-stick that combines its natural advantages with those of a light. A small flash-lamp is fixed in the handle of the stick. The handle is hollowed out to accommodate the battery, while the lens and the small electric bulb are fixed in the tip of the handle. This same principle might be applied also to umbrellas, as a convenience on dark, wet nights. A Self-Closing Two-Way Gate Sawer is a gate that swings on a centrai post which has a short iron rod in- serted at top and bottom, the top rod pass- ing through the lintel of the gateway, the bottom rod working freely in a block set in the ground. The gate is hung by two chains to the lintel, the fastenings being on each side of the center post of the gate. The center post rises as the gate opens. The principle of gravity could scarcely be more satisfactorily applied to a simple contrivance for every-day use than it is in this contrivance. Popular Science Monthly a ee: He Makes His Rounds on Skates MAEING the round of inspecting fire hydrants, the policeman who has to cover a long beat may find himself slipping on his job when the streets are covered with ice. A policeman in Columbus, Ohio, got around the difficulty by directing his slipping to a purpose. With skates on his feet, he found that he could make bet- ter time covering his rounds than when he walked on a dry pavement. If, by chance, he should meet a thief, he would have the advantage in a chase over icy pavements. How the Thrust of a Propeller Is Measured HE air-screw or propeller of the air- plane, while far from being in an ex- perimental stage, is still subject toscrutiny by inventors. Not only are improved methods of manufacture being studied, but the shape and power of the propellers are also being examined and tested, in the hope of reaching greater efficiency. One method of testing is that shown below. The propeller is attached to a car which runs on rails ‘that offer the least resistance. But the car is attached to an overhead device which enables the ‘‘pull’’ of the propeller to be accurately measured. This makes it possible to compare propel- lers of different types. © Mirzaof-Boyer

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December,:1920 * A Palin Support _ for the Beginner HERE you see a pen- “#4 holder support that teaches you the proper way to hold a pen. It is made of spring wire and has a loop at each end. One loop fits over the little finger which rests on the table, and the other fits over the holder. The length of the wire between them is sufficient to keep your fingers from becoming cramped. You are forced to hold the pen loosely and thus you write smoothly. The loop that is placed about the pen- holder can be adjusted to any position you desire, thus changing the angle of the holder. Is there anything in that idea of one’s penmanship indicating character? Irrigation by Horsepower in the Holy Land AMASCUS, one of the oldest cities in the world, is far behind the smallest American desert town in the matter of irrigation. Instead of using a pump for raising the water from the river, a team of horses aided by a windlass does the work. A leather bag is lowered into the river, where it takes on a load of water. Then the horses are driven forward. As a re- sult, the ropes that are attached to their harness and passed across the windlass draw the bag up to a level with a trough that leads to a ditch. The bag is tipped, the water;runs into the trough and into the > oe ox irrigation-ditch. © Underwood & Underwood Down Comes the Steeple to Thrill **Movie Audiences”’ [IGETNING has always been a great enemy of church steeples. A glance at this picture would tend to make one believe that the airplane will also do its share in destroying steeples. Not so, however, since this picture is of another “movie” thriller. The church steeple is constructed of very light mate- rial, so that there can be no danger of damaging the airplane. In case of a real argument between a real church steeple and a real airplane, the airplane would be sure to lose. ° This stunt was not accomplished with- out any danger, however. Few movie stunts are. When the airplane struck this steeple it was traveling at high speed—probably from sixty to seventy miles an hour. At this tremendous speed the aviator was taking a great risk by allowing his machine to strike anything, no matter how frail or delicate. When a machine is traveling at this high speed, it does not require much to upset its balance and dash it to earth with its occupants. Neatly Bringing a Soft Collar Together ORE and more do men wear soft collars the year round. The soft ones are comfortable, easy to put on—but they do not look as well as the stiff ones. Some people object to buttons and buttonholes that hold down the ends. There is now a slip-on fastener that clasps both ends. firmly and holds them down close to the neck- band. The fastener consists of a slightly curved bar with a double loop at each end.’ The space between the sides of the outgoing loop is so small that the collar edge can barely be slipped through it. Once inside, the edge is held firm. These fasteners have been made in various metals and designs to suit every taste. An Automobile Made of Luggage TAND a hatbox on its side and it looks not unlike one of the disk wheels with which some cars are adorned. Then there is the trunk with the curved top; does it not resemble the hood of an auto- mobile ? The proprietor of a Berlin leather goods store noticed these similarities, and de- cided to build an automobile out of his wares. Hatboxes, suitcases, “‘grips,’”’ and satchels were used chiefly. One small satchel made an excellent tool-box and was placed on the running-board. When this luggage-made automobile was finished, it was placed in the window of the store and attracted crowds.

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A Motor Snow-Plow for Sidewalks VERY one is familiar with the small gasoline - engine lawn - mower as it speedily travels around the large lawns of city parks in summer. We may wonder why such a device has not before been adapted as a snow-plow to clear the side- walks after a winter storm. The man who has to swing a shovel in the hard work of getting the snow cleared away from a long stretch of pavement will certainly appreciate this invention. Em- ployed by a traction company, it serves well to clean off the street corners where the cars stop, making a wide path for the passengers who are waiting for cars. Easily portable and easily controlled, this hand snow-plow can combat the heavy masses of a formidable snowbank, and-in . ’ cleaning sidewalks is very efficient. Rover Makes a Clever Caddie N Airedale will make a very capable caddie if he is trained to carry the golf-sticks and to “stick” around. Golf is such a leisurely played game at times that one’s caddie may stray away and not be at hand when most needed. A dog is more likely to stay close to his master, and as the burden of sticks is not a heavy one, the animal will not be in- humanely treated if he is required to make himself useful instead of merely: lazily present. This particular dog caddie actually has become an enthusiast of the game. At every shot his attention is on the alert, and he watches the play with the keen : eye of a connoisseur. Not only that. His mistress never loses a ball, for the dog’s eyes follow it attentively, and running to thespot where it lies, he waits for his mistress to come up and take another shot. One of Our Bird Veterans of the War Ce pigeons won distinction by heroic service in the great war. Some of the bird members of the pigeon section of the Signal Corps were killed or wounded. In charge of the twelve thousand pigeons were twenty officers and 542 enlisted men. The miile-a-minute speed of the birds enabled them to convey messages from inaccessible places. At St. Mihiel, 567 American homers were used. Twenty-four out of 202 were killed when released from tanks in action. One of the homers used in tank work, “President Wilson,”’ with his leg shot off, flew through fog and rain, and heroically won official commendation. This hero was one of the veterans exhibited in St. Louis at the convention of Rexall drug- ‘gists in September. The Wood Used to Make a Sunday Paper f tw principal cause of the present paper shortage is the fact that no satisfactory substitute has ever been found for spruce wood. It is said that one great New York news- paper devastates ninety acres of spruc timber every day. Ten years ago the United States pro- duced all its paper pulp. Today it im- ports two thirds of it, and our spruce for- ests are dangerously near extinction. The big Sunday newspaper above weighs nearly two pounds, and the approximate . amounts of the materials in it are shown beneath it. They are one ounce of bleach- ing powder, two pounds of coal, one ounce of sulphur, one and one half ounces of un- slacked lime, red and blue dyes, and three pounds of sprtice wood. If the paper is to have a smooth finish, rosin and. other materials are added as “‘sizing.”’ 68 Popular Science Monthly A Headlong Flying Leap on Skates AKE PLACID, in the Adirondacks, holds a peculiar charm for the winter sportsman. The hills afford an oppor- tunity for skiing and skijoring, while the smooth surface of the frozen lake invites such games as curling and hockey. But skating meets the all-round popular de- mand, and to Lake Placid in midwinter come the world’s champion ice-skaters. Stunts such as jumping, dancing, and ice-acrobatics are much enjoyed by the crowds of visitors. The photograph above shows Earl Palmer, of Plattsburg, New York, in the act of making a daring jump over three barrels. This took place during the con- tests for the international championships. From the attitude of the skater’s body the “‘landing’’ looks precarious. Good Tops Make Good Barrels Fy you ever try to get a barrel-top off without making kindling-wood of the barrel? It is a trick that most people cannot do with an ordinary barrel. With the barrel shown below it is differ- ent. It is not necessary to use a sledge- hammer on a barrel with a wedge top. The top is made in three pieces. The middle piece is wedge-shaped, and when it is pushed in between the other two pieces, they are forced into place, where they remain until the center piece is taken out. Ponular Seience Monthly,

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December, 1920 Setting Small Jewels in a Watch HEN it is necessary to use a mag- nifying-glass to see distinctly the tiny jewels that every good watch con- tains, one is naturally curious to know how such minute objects are set properly in their places. These tiny jewels must be ground in precise geometrical forms and exactly set, to be useful. ; A jewel-setting tool, the invention of Carl Culman, of Maplewood, Missouri, is a device to help the watchmaker. It is so constructed that one jewel may be set in without interfering with another that is already in place. In appearance the jewel-setter resembles a cross between a surgical instrument and a pair of pliers, but it is like neither. It can be used in various operations in repairing a watch or a clock, where very small objects and delicate work must be handled. Messrs. Winter and Water, Nature Sculptors URING the cold weather a water-main broke and sent up a spout of water about eighty feet in the air. Of course, the water had to come down. It fell and quickly froze in beautiful festoons along the limbs and branches of the trees in the neighborhood, making grotesque shapes of silvery whiteness. In the morning sunlight, the ice glittered and sparkled, and the sight of a group of ice-trees in the heart of a city attracted crowds of visitors. é It was the extraordinarily intense cold that caused the water in the main to freeze and the expansion of the water caused the pipe to burst.’ But the pressure of the water in*the main was too strong for the resistance offered by the ice-plug—so the spouting water shot high above the pave- ment. © Kadel & Herbert A Clock that Literally Tells the Time AVING studied the matter for sixteen months, Vincent Pinto and his son Joseph, of Philadelphia, invented a clock that talks. The old saying that “time will tell’ is now areality. The clock speaks the time instead of striking the time at certain intervals. It can be made to speak at any time dur- ing the day; but for convenience the model clock has been regulated to speak every quarter of an hour. A few seconds before the minute-hand reaches the quarter hour, the mechanism is set in operation and an- nounces the time with an appropriate or humorous remark. For instance, in the morning it serves as a reminder to get up. At seven o’clock, besides announcing the time, it can be made to say that breakfast is ready. At four thirty in the afternoon it will remind mother to prepare dinner. At eight in the evening the children may be reminded that they should be in bed. The entire mechanism of this useful attachment may be condensed to fit into an ordinary table or mantel clock. Rubber Tire Patches Make Good Rubber Heels MAEE your own rubber heels and toes from tire patches. All you have to do is cut down the patches to fit, and glue them firmly to your shoe, and they are all ready for service. -You will probably never want to use the patches on your inner tubes, anyway —it is so much easier to pay a quarter or a half dollar to have a tube patched at a garage than to do the job yourself. Toe patches have become quite necessary since women have taken to long-pointed shoes. After a few weeks of use the points become dull and worn to a wafer at the extreme point, and either new shoes or patches become necessary. These tire patches are likely to be useful in various other ways around the house. That leaky hot-water bag can be made whole; likewise the hose of the bath-spray or the garden sprinkler. Now Is the Time to Make Your Own Ice A TRESTLE carrying a device similar to a lawn-sprinkler, so that the water is sprayed across its top, makes a satisfactory midwinter ice-machine. The water will freeze in successive layers as it trickles over. When ice may be properly stored, there is no better way to take advantage of winter to obtain a fresh, clean supply of it. The swinging or rotating motion of the sprinkling device will distribute the flow of water so that it will not form the ice all in one spot. The ice shapes that are created from such tiny particles of water may thus be made serviceable when stored -away for next summer. When a fine, misty rain freezes upon the branches and bushes, the garden and the woods both become places of beauty. Now it is possible to create artificially the same effects. ee TOON

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A Steel Punch and Bender ee man who would punch holes in a steel bar, or who would bend strips of metal, needs a machine that has great strength of construction, and that can be easily manipulated. Here is a steel punch and bender that can be changed from one to the other without loss of time. Hand levers apply the pressure to the bars holding the various tools. If the machine is to be used as a punch, just slip the punch and die holder with the bolt in the slot, and from all sides the punch is visible to the workman. More than one punch and die may be clamped in the machine at one time. A Sled that Is Propelled by Hand [‘ some parts of Europe farmers use spikes to provide a means of motive power for crude sleds. The spikes are dug into the ice and thus a man can propel himself over the smooth surface of the ice. The device is a simple application of that now. employed -by arctic explorers in motor-driven sleds. There the smooth runners enable the vehicle to slide with least resistance, while iron-spiked wheels, or “‘caterpillars,’”’ propel it along by engag- ing the ice in a firm grip. Safety First for the Man Who Oils the Machinery Dp” you ever hear about the man who tried to oil machinery while it was running, and who stood upon the top of a stepladder to do it? Well, the ambulance got him first, and then the undertaker came for him. The ladder slipped on the oily floor and the machinery did the rest of a disastrous job. To prevent such accidents there is an oil-can having a long extension which en- ables a man to stand upon the floor and reach every part of the machinery that requires oiling. A long spout connected with the can, arranged to send the oil up to the top of the spout, is the handy equip- ment that should be installed in every factory. The Coal-Stove Unadorned A COAL-STOVE should be as plain as possible. Isinglass windows and nickel-plated trimmings simply admit air through the joints. As the air seeps through the joints and cracks, the heat within the stove is decreased. A coal-stove, chosen at random, was tested by one of the members of the American Society of Heating and Ventilat- ing Engineers for the amount of carbon- dioxide directly over the flame and in the chimney. Nine per cent of it was found over the flame and only four per cent in the chimney. In preparation for a subsequent test, all the air leaks were then sealed up with cement. The second test revealed eleven per cent over the fire and eight per cent in the chimney. | 70 Popular Science Monthly A Spring Hanger for Clothes NEW metal clothes-hanger upon which one can quickly dispose of the garments in a closet has been invented by John L. Lyman, of Easthampton, Massa- chusetts. This hanger differs from the ordinary clothes-hook in that it embodies a device by which the article placed upon it is held in a spring grip. It takes up the minimum of space and permits a number of garments to be hung upon it. The device consists of a single piece of wire having a suitable amount of resiliency to grip the garment by spring tension. It can be placed in the panel of a door or attached to a shelf. Bobsledding When There’s No Snow = Switzerland many people have put wheels on their sleds and enjoy all the thrills of coasting down hills even though no snow has fallen. In fact, many sleds are made originally with wheels instead of runners. The chief objection to snowless coasting is the danger of spilling. You land on hard, dry, resisting dirt, and are very apt to bruise yourself or at least ruin your clothes. Snow, on the contrary, is usually harmless, unless it is frozen hard.

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December, 1920 No Fire on This Locomotive ** A N odd-looking locomotive,” you will say. It is a locomotive without a fire. How does it run? By steam, of course. The steam is not generated on the locomotive, but in a separate boiler located in the yard. The boiler of the little locomotive is used only in storing steam. Steam is pumped into the loco- motive under considerable pressure. This finds its way into the cylinders through a valve which reduces the steam pressure to about one third the pressure in the boiler. This method of locomotion pre- vents the buildings about the yard from getting dirty and also elimi- nates the fire risk, which is most important. Hercules in the Locomotive Shop VW HEN locomotives are repaired, it is no longer a case of getting out and getting under. That is too much trouble. The modern method is to raise the loco- motive. Hydraulic pressure is used in lifting the locomotive from the floor of the shop. A large locomotive can be placed on the lift and hoisted up a distance of five or six feet in a few minutes’ time. This hydraulic hoist is capable of lifting a weight of two hundred tons with ease. Hoists of the same design, but having six posts instead of four as shown, are made to lift a weight of three hundred tons with- out groaning. The six-post hoists are used with long locomotives, so that no strain will be imposed upon them. a ATU Visit rs Ps 4 Repairs Overhead Wires HERE is a new way to get into the air to repair overhead wires for trolley- cars. This tower is comparatively light in weight, but it is so constructed that several men may work on the platform without danger of it collapsing. It is trussed in the manner of a bridge. When the tower is not in use, and during trans- portation, the upper half is telescoped into the lower half and the whole thing is allowed to drop slowly until it comes to rest on the bottom of the truck carrying it. In this way it can be carried from place to place without trouble. The whole structure can be brought to position by one man. It is necessary only to control the motor, which motion is “transmitted to the tower through a train of gears. When the tower is brought to an upright position, the upper half is raised by power to the height desired. A New Tower for the Man Who A World’s Champion [2 above and you will see the world’s fastest typist. She has copied one hundred and fifty-one words in one minute. This is a speed of more than two and one half words a second. Attention must be given to details to attain such a record. For instance, the typewriter | should be fastened securely to the desk without the drop-bed feature. The drop-bed tends |. to increase vibration, and this interferes with high speed. The typist should have a fixed back chair with her knees braced against the desk to keep her the proper distance from the machine. This Is a Busy Little Car | ‘T car pictured below is used in a great chemical plant. It is kept busy measuring out large quantities of the dif- ferent ingredients that enter into the proc- ess. It is driven electrically and runs about the yard measuring out so much of this and so much of that. The large kettles carried on the upper deck of the car are the measuring units. They are filled up and lifted off with the electric derrick mounted on the top. While this may appear to be a crude method of measurement to those who are accustomed to smaller units, it is accurate enough for use in the production of large batches of various chemical products. This car is used in a by-products coke plant. lata!

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Popular Science Monthly Fighting the H.C. L. By exercising a little a few hours to home other ways of reducing

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By drilling a small hole in the nearest steam-radiator, threading the hole, and from it conducting a pipe ending in a swivel arm to the kitchen sink, Hugh E. Westfield, of Rockland, Massachusetts, obtained hot water all winter at small cost. The flow of steam is regulated by a valve above the swivel arm

Left. With a coal- or wood-burn- ing stove in the cellar, Charles E. Upton, of La Fargeville, New York, defies the coldest winter blasts. He conducted the stove- pipe through the kitchen floor, carefully protecting the wood- work, and connected the pipe with that of the kitchen range. It meant greater economy Right. Three or four sheets of newspaper, folded once and then rolled tightly and twisted to- gether, make a good substitute for wood in kindling a fire in the stove or grate. William J. Albin, of Oakland, California, who sug- gests this method of saving fuel, finds that paper rolls burn slowly and give much heat

Percy L. Anderson, of Wilmington, Delaware, saved fuel by From an old railway-car stove H. M. Beach, of Fort transforming a small coal-stove in his cellar into a hot-air fur- Plain, New York, improvised a hot-air furnace. He nace. He put a tin box around the stove, conducted a hot-air surrounded the stove with a tin jacket in a walled-in pipe through the floor of one room, and put a register around space 6 by 6 feet. Around the pipe he placed a drum the smoke-pipe in another room communicating with the room above ee Sie an) Dee.

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December, 1920 at the Cellar Furnace ingenuity, and devoting tinkering, you may plan living expenses When the hot-air furnace in his cellar is in use, Jacob A. Ruof, of Philadelphia, saves much coal by heating the water for kitchen use in pipes which form a loop in the fire-box of the furnace. At such times the gas-heater connected with the water- tank is not required at all Left. By utilizing the waste heat in the chimney, William H. Morin, of Oxford, Massachu- setts, achieved a considerable saving of coal that would have been required for heating the _water for kitchen use. He placed the water-pipe’in the chimney, connected the upper end with the kitchen faucet, and the lower end with the supply-pipe Right. For the purpose of sav- ing fuel, C. L. Meller, of Fargo, North Dakota, set up a sheet-iron drum in his living-room and con- ducted the hot gases in the chimney through the drum by connecting it below the floor and near the ceiling of the room with the flue With a discarded rain-pipe, eight feet long, and the flame of a gas-burner in the living-room, William L. Wray, of New York, kept his family warm when a cold day found him without coal. By filing a hole in the lower part of the burner he made it a Bunsen burner By connecting the hot-water tank in the kitchen with a radiator in the room above by means of pipes, Arthur Johnson, of Ironwood, Michigan, * heated that room comfortably without extra ex- pense throughout the cold season, when the kitchen range was in constant use

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Popular Science Monthly Fresh Fish from Sea to Door by Motor-Truck To make the motor-truck serve your business efficiently make a study of the handling and transportation problem OTOR-TRUCK transportation M is so new, as compared to the other forms of rail and water transportation, that the prudent busi- ness man will do well to make a thor- ough study of his transportation problem before he in- stalls trucks in place of By Joseph Brinker portation problem will enable the busi- ness man to decide whether trucks can be made to save him money in his haulage or delivery. If the first analy- will speed up the truck, cut the idle time to a minimum, and make it not twice but three or four times as efficient as the horse-wagon. Again, it may be that demountable bodies will solve the problem—bodies that can be rolled off the truck chassis or

horses, or substitutes highway for rail or water shipments. The need for this study is due to the fact that the motor-truck cannot be run on_ horse - pace methods and achieve its greatest degree of economy. A Truck Must Give methods. horses go out. The Difference between Horse- Wagons and Motor-Trucks Too: often business men attempt to install motor-trucks in their businesses on horse-pace The trucks simply come in when the Because motor transportation and horse haulage are inherently different, the greatest economy of trucks cannot be secured if lifted off by a crane or derrick. Although it is not often considered, the method of handling the goods just before they are loaded on the trucks or unloaded from them has a great deal to do with the efficiency of truck the merchant simply introduces the new form of operation. Double Service delivery for the old without other changes that : will speed up the handling and loading of the Study the Loading On the average, goods to the same degree as the truck speeds up Problem First truck equipment will the actual delivery. ; cost approximately In this article, the sixth of the Popular Science For example, if the double the horse - Monthly series on truck transportation for .the goods haveto bemoved wagon outfit to carry the same load. There- fore, at the outset, irrespective of the higher operating costs, the ‘truck must do twice as much work as the horse in order to perform the work at

business man, Mr. Brinker shows what excep- tional economy may be secured by the use of trucks if sufficient study is given to the particu- lar haulage problem under consideration. loading and unloading means bodies; to secure the utmost efficiency the use of | trailers may even be necessary. : demountable | on hand trucks over a long distance from the point where the load is made up to the tail- board of the truck, . there is liable to be considerable delay in loading. Meanwhile the truck is standing Rapid

the same cost per ton, load, or package, as the case may be. Owing to its inherent speed, the truck, in ninety-nine cases out of a hundred, can do twice the work of the horse equipment—pro- vided it is kept moving and used as a vehicle instead of a warehouse on wheels. Only an advance study of the trans- BRINE-TAN a

N. DE-MOUNTABLE ion The latest plan to deliver fish to the kitchen involves the use of 134-ton trucks. sis of the problem shows that the trucks will be standing still for the greater part of the working day, some means must be provided for reducing the idle standing time. Sometimes it may be self-dumping bodies for un- loading, and overhead hoppers with chutes for loading bulk material, that COOLING PIPE COILS _AIR-TIGHT DOORS )

a 74 - idle, thereby reducing the amount of work that it can do in any given time. Similar delays are caused when the loaders have to lift the goods in placing them in the truck body. Delays of this nature may be avoided by the use of small industrial electric trucks to move goods from the points of pick-up to the tail-boards of the trucks. These ms <i, Loaded from the local warehouse, the fish are péddled from house to house. The trucks have glass doors, so that the fish inside may be seen

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December, 1920 | SHOVELING ri NET INTO BRINE-COQLED BODIES i SRINE-CIRCULATING PIPES ST TT ———— The hatchways of the fishing-smack between the foremast and the mainmast are so arranged that four truck bodies can be carried in the boat to the fishing-banks. Doors at the tops of the bodies are opened, and the fish are pitchforked directly into the truck bodies small electrics carry much more than a man can push on a hand-truck, are speedier, and are not subject to human fatigue. Various Ways to Speed Up Loading If such vehicles are not suitable, spiral gravity chutes may be employed to get the goods quickly from the upper floors to the shipping-room from which they may be moved directly to the truck without lifting by gravity roller conveyors. . f , Industrial trucks and roller con- veyors may also be used successfully to get the goods off the trucks quickly and back from the edge of the plat- form, so that the next truck in line may unload without delay. Trailers may be employed to ad- vantage in many instances, permitting greater loads to be carried on each trip, with on!.7 a small increase in initial investment and operating ex- pense. Then again, besides the auxiliary equipment, it may be a combination of all three — quick-loading cranes, demountable bodies, and trailers—that will solve the problem most effectively. This proved to be the case after a thorough study of, the distribution of fish over the highway, as: told in the accompanying story and illustra- tions. At the present moment the distribu- tion of fresh fish for short distances by motor-truck is but the germ of an idea, which, however, must be worked out La4 (uv in greater detail before perfection can be reached. It has certain advantages under favorable conditions, especially at a time when the railroads are unable to move goods quickly because of terminal or other congestion. The sponsors of the plan do not claim that the motor-truck can compete with the railroads for the distribution of all fish. Where the Motor-Truck Is Valuable In their own sphere of long-haul shipments under ordinary conditions, the railroads are supreme. They can move fish or other goods much more economically than any other means known. For short-haul ship- ments, especially in periods of railroad

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embargoes and other delays, however, the motor-truck has certain advan- tages, the principal ones of which are to get the fish delivered quickly and to save handling. In the saving or reduction in the number of handlings, the opportunities of the truck are enhanced by the development of a new form of refriger- ator body in which the goods carried never come into actual contact with ice, but are kept cool by means of cold brine circulated through pipes inside the truck body. By this body it is possible to keep a load of five tons of fresh fish at any desired temperature by the use of not more than two hun- dred pounds of ice a day, whereas several times this amount of ice would be required were the fish. packed in between layers of ice in the usual way. A still further reduction in the num- ber of handlings may be made by the adoption of the demountable unit-body idea, which has been used with such great success in recent years for the delivery of groceries, paper, and other commodities. Truck Bodies in Fishing-Smacks Save Time in Handling The whole plan, from the time the fish are scooped out of the water in nets until they reach the table of the housewife, is shown in the’ accom- panying illustrations. The first new idea in the proposal, outside of the fundamental one of using trucks, is to change the hatchways of the fishing-smacks between the foremast and the mainmast, so . that four of the truck bodies may be carried in the boat to the fishing- banks. The fish caught, doors in the tops of the bodies are opened and the fish pitchforked directly into the truck bodies. The latter are arranged longitudinally and side by side, with horizontal parti- tions or shelves in them, so that the fish on the bottom are not crushed by the weight of those above them. Since each body can carry five tons, the small fishing-smack will be able to bring home twenty tons of fish to the catch, although it is probable that a future development of the idea will result in the design of a boat that will carry eight or more bodies simultaneously. When the catch is made off the New England coast, and it is de- sired to ship. fish west to Buffalo and points beyond, the boats would find it ‘most’ convenient to run to Boston, where there are through rail connections to the West by way of Albany. If it is desired to ship to New York, how- ever, the boat may make some nearer port, where the filled bodies may be lifted off and shipped directly by truck over the _high- way. In either case, some unloading means must be provided, such as an ordinary derrick, at the point of call, so that the bodies may be hoisted out. of the hull and placed on either a railroad flat-car or a truck. The bodies are so proportioned that two of them may be loaded upon an ordinary freight platform car. Only one body can be loaded on a five-ton motor-truck, but a second body may be carried on a trailer behind the truck, so that for long hauls the total load will be ten tons. So far, one handling is avoided, the fish having been transferred directly from the boat to the freight-car or motor-truck. Under the _ present scheme they would have to be first unloaded into an ice-house and then into a refrigerator freight-car or the truck body. At the end of the haul, another handling may be saved with the new system in that the truck may proceed directly to the place of business of the consignee, or the bodies may be taken from the freight-car and put on trucks without having to pass through an ice-house. Meantime, the fish have been kept fresh without icing, and are just as good as when taken out of the sea. A i § FISHAGROCD Pate wO BODICS TO ONE CA (FOR LONG SHIPMENTS® wh of er 4 Popular Science Monthly Up to this point there have been no steps in the truck distribution scheme that are at all impossible. But what about returning the bodies? When salt-water fish are shipped West by rail, it is intended to use the same bodies to bring back fresh-water fish from the Great Lakes, so that the bodies will be working in both direc- tions. This would of course be impos- sible with the bodies mounted on trucks that run along the Eastern sea- board; but even these bodies on the return trips may be utilized to carry canned goods, which cannot be con- taminated by fish odors in the body itself. Carrying Fish from the Sea to the Housewife The last step in the plan to get the fresh fish to the kitchen of the con- sumer is to employ smaller trucks of from one to two tons capacity. From the local warehouse, these trucks may be loaded and the fish peddled from house to house. As can be seen in the illustration on page 74, these smaller trucks may have glass-sided doors, so that the fish inside can be seen. Such a plan would help to popularize the service, since every one who saw the truck would know that it was carrying fresh fish. The motor-truck bodies, laden with fish; are hoisted out of the smack, placed upon the chassis of a waiting motor-truck, and then carried over the highways to their destination Popular Science Monthly

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December, 1920: A Pulverizer Plant More than One Hundred Feet High CID phosphate fertilizer is one of the essentials of modern agriculture. The designers of the gigan- tic mill shown in the picture below decided to employ gravity to convey the pulverized phosphate rock through thelaststep §€XCLONE.. in the process of produc- ing acid phosphate by lift- ing the powdered rock up through the pipes to the “eyclone collector,” which is more than one hundred feet above the ground. The bucket - shaped machines are the pul- verizing mills that re- duce the phosphate rock to powdered form, after which it is forced up to the top of the plant by means of sev- eral blowers. Each of the pul- verizing machines has a minimum capacity of four tons of pebble rock an hour, re- ducing it to a fineness that al- lows it to pass through a_two- GROUND ROCK? CONVEYORS Jersey City’s water-supply pipe, which rests on the bot- tom of the Passaic river, in process of construction An Under-Water Water-Pipe ERSEY CITY’S water-pipe line lies twenty- six feet below the surface of the Passaic river. The submerged pipe has an inside diameter of six feet and is more than four hun- dred and fifty feet long. It weighs about a ton a foot. How did it get there? First, a trench was dug on shore and a _ launching-way laid on it. * As the pipe was built it was supported on cars that ran on tracks in the trench. When the tracks reached the water’s edge, two parallel trestles were built, and the pipe was further supported by cars that ran on top of each trestle. When hundred mesh the pipe was finished, it was sunk and weighted The world’s largest pulverizing plant employs screen. gravity in the process of producing acid phosphate down with cast-iron blocks. The Telephonic Eye Betrays the Burglar HE newest foiler of burglars is the ‘“‘telephonic eye,” invented by Dr. Oscar Hannach. What makes the telephonic eye so sensitive and efficient is the fact that no mechanical agency is re- quired to operate the apparatus. The faintest beam of light is sufficient to set it working. In fact, the vital organ is a sele- rium compound cell of truly un- equaled sensitiveness to variations of light. It infallibly signals the presence of any undesirable visitor, as well as the series of current impulses into the telephone line, thus lighting the sub- scriber’s call, group, and pilot lamps at the telephone exchange. The tele- phone girl on duty notes the signal and immediately transmits the alarm to the police station. The same apparatus, how- ever, lends itself to a multitude of combinations and applica- tions. An electric bell may alarm the porter or guard; a flashlight may photograph the intruder; an automatic device may, at the very moment the alarm is given, bolt all the doors and windows and light When a burglar enters a darkened room and operates his flashlight, or even lights a match, the telephonic eye will be affected and will flash an alarm to either the police station or the telephone exchange December 1920 The new telephonic eye is made of sele- nium and is very sensitive to light changes outbreak of fire, at the telephone ex- change or police station. All you have to do, on leaving home, is.to let down the blinds in any room to be especially protected, and to turn the switch of the telephonic eye. Un- able to operate in the dark; an intruder must use a lamp or lantern. But, even if he burns only a match, the apparatus automatically throws a 17 all the lamps in the house. Should a mischief-maker cut the wires, he would obtain a result diametrically opposed, to his intention. . The apparatus is set in operation automatically by any accidental or voluntary disturbance. The slight glow of an incipient fire obviously has the same effect as the lighting of a match or lamp, so that the apparatus is also a fire-alarm.—Dr,. ALFRED GRADENWITZ. i | \ | BY |

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You’ll never burn your hands while taking pots off the Stove if you use the detach- able handle shown above. The arms of it are so curved that they will grasp any pot securely Housekeeping Made Easy Popular Science Monthly The bristles in this metal toothbrush can be taken out, cleaned, sterilized, dried, and then replaced ready for use again. They are very strong and will stand a number of baths Many a woman has fallen and been hurt while hanging clothes on the line. Don’t take any chances; buy one of these extension pulley-lines which enable you to do the hanging indoors. You can remove the extension arm when you're finished, and close the window When you put meat into this chop- per, you don’t have to press the meat down with your fingers. There is a pressing lid operated by a han- How tired your hand gets when you hold an egg-beater steadily for sev- eral minutes. Why not bolt it to a bracket on the wall when you use it? dle. This chopper cuts and grinds oe Heretofore ash-trays and smok- ing-stands have ignored pipes, while providing parking space As gaslight is thrust aside by electricity, 1 ; many gas-mantle protectors are without for cigarettes, cigars, and jobs. Fill one with bits of soap and matches; this stand has accom- ¢ c attach it to the hot-water faucet when modation for a pipe you are going to wash dishes . The bulb form of atomizer has a German rival. The hollow handle is a pump which, when raised, will suck up the liquid, and when lowered will force it out The carpet-sweeper is father to the new table-cloth cleaner shown here. It is made of silver, has an ebony handle, and carries a small revolving brush beneath a — a ae ae ee ee ee

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December 1920 Keeping Up with the March of Science Facts for the man who wants to know How Airmen Use Oxygen HEN an airman ascends to heights greater than twenty thousand feet, he is sure to use oxygen. He carries it in liquid form in a vacuum tank provided with a mechanism to control the evaporation. The liquid may be electrically heated to accelerate evaporation; or a heated rod of copper or aluminum in the liquid may be used; or the liquid may be siphoned out into an evaporating chamber from which the gas is conducted through tubes to the airman’s mouth. Flowers that Serve as Food REMARKABLE tree in India is known by the natives as the mowra and by ourselves as the ‘‘Bassia tree.’”’ Of its three varieties one produces the butter-seeds that have been much used in the manu- facture of margarine, soap, etc., in Europe. Another tree of this interesting family furnishes a flower: that is rich in sugar. The natives in the centrak provinces use it as a regular food: The flowers of the “butter tree” are not eaten,.but a syrup is prepared by boiling them down, yielding a sugar of about the quality of date sugar. The flowers of the mowra are globe- shaped and of a pale cream-color, and are collected when they fall upon the ground in the early hours of the morning. A Bassia tree will give about three hundred. pounds of flowers in a year, and from a ton of the dried flowers chemists can produce ninety gallons of ninety-five per cent alcohol. Have You Euphoria? i takes a doctor to give a high-sounding name to a well known phenomenon. “Euphoria” means “feeling fit.”” It is as much a physiological fact as scarlet fever. Nature makes it worth while to be alive simply through euphoria. The joy of mak- ing a good tennis stroke, the delight that a woodsman gets in the open air, the artist’s rhapsody—all are due to euphoria. Why do we drink aleohol—when we can get it— or smoke tobacco? To affect euphoria. When a lunatic thinks that he is Napoleon and demands the homage due an emperor, he has euphoria in its worst form. Too little iss known about euphoria. Since it can be affected by drugs and chemicals, who knows but it may have its seat in some gland? A Rival of Acetylene A NEW gas has been developed from the manufacture of alcohol which can be compressed to 3500 pounds to the square inch and stored safely in steel tanks. It has a pleasant odor and has no harmful effects of its products of combustion, and it also gives better cutting results through thick metal. The high temperature reached by a flame of gas used for cutting. metal de- pends largely upon the power of the gas to liberate heat faster than it is absorbed and conducted by the metal to be cut. Of course, the gas must have also a high heat- value, which it is able to maintain. Carbon, not retarded by some other element in the process of cutting, is the chemical agent in a gas which produces the most rapid com- bustion. The successful cutting gas should contain a large percentage of carbon, should be unsaturated, should be combined with the lowest proportion of slow-burning gas, and should have a high rate of combustion. The new cutting gas meets these conditions second only to acetylene. It is obtained from processes in the manufacture of alcohol. A temperature of 6200° F. can be reached with the new gas, compared with 6800° F. for acetylene. What New York Eats | inwinck thousand cars of eight leading fruits and vegetables are consumed annually by the seven million people who live in the metropolitan district. These cars would make a train three hundred and seventy miles long—from New York city ‘to Rochester. New York consumes about fifteen per cent of the total quantity of apples, potatoes, cabbage, onions, tomatoes, -straWberries, cantaloups, and peaches shipped each year. In the four years from 1906 to 1909, inclusive, 195,354 cars of these products were received at New York terminals. This is a yearly average of 48,838. These quantities do not include the vegetables brought into the city by trucks. Coal-Mine Explosions HE power lines that supplied one of the mines in the Pittsburgh district needed repair, and in consequence the mine shut down over Sunday. In the meanwhile the lines were repaired. As soon as the power was restored the ventilating fan was turned on, and shortly afterward the switch that controlled the underground sections was thrown in. There was a deafening roar— the gases in the mine had exploded! The cause of the explosion will always remain a mystery. But it seems probable that a short circuit on one of the lines caused a spark when the power was switched on. The gases that had accumu- lated while the fan was not in operation readily ignited. Keeping the Subway Dry Ul serenen passages are always difficult to keep dry. Water from various sources seeps in. In New York a large sum of money is spent yearly to keep the subways dry. Automatic electrically driven pumps are used. -Water that leaks in collects in a sump 9 which is provided with float switches. When the water in the sump passes a cer- tain level, the float switch closes the electric circuit and the motor is started. Where the subways pass under the river, emergency motors connected to high- capacity pumps are used to prevent flood- ing. These pumps are also automatic in their operation. Earthquakes in Panama ere hundred and fifty-seven earth- quakes were recorded by automatic instruments installed in the Canal Zone from 1906 to the end of 1909. This is not so alarming as it may seem. Even a Northern city like New York has its tremors every year, although they are too slight to be felt. The most important disturbances, as far as the Isthmus of Panama and the Canal are concerned, are those that originated less than two hundred miles away; but these no one noticed. Tin, an Abused Word "EN is a loosely used word. Sheet metal of any kind is usually referred to as tin—from “tin” cans to “tin” lizzies. Pure sheet tin is not in general use, and never will be, because the metal is not abundant enough. The tin cans used to hold food-stuffs are really made of sheet iron. Iron itself rusts when exposed to oxygen. Tin is not affected in this way. To make sheet iron cans safe to use, they are immersed in a bath of molten tin. In this way a thin film of tin is caused to adhere to the iron, protecting it from rust. At present tin sells for about ten hundred and fifty dollars a ton. If cans were made of tin they would be too expensive for general use. The Poisons co! Animals M22RE progress’ has been made in studying plant poisons than animal venoms, obviously because plants are fixed and can be gathered in great numbers. As many as twenty thousand serpents had te be captured by a single explorer in order to obtain enough venom of the species to make all the analyses required. Similarly, the examination of bee poison means the capture of 200,000 bees and the isolation of their venomous juices. As a result of these modern researches, it is now concluded that there are two great classes of animal venoms—those that contain nitrogen, and those fhat are free from nitrogen. There is a close re- semblance between non-nitrogenous plant and animal poisons. Cantharides (“Span- ish fly’) is found in a few bugs and in some plants. Some serpent poisons find their chemical counterpart in plants. It has been proved that animal poisons do not belong to a new class of chemical e SS oe ‘ aes yee teers chr ei of gy RWS Nee ETM SS a ta ee

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compounds. Some day they will be made artificially in the laboratory for medicinal purposes. In some snakes a venom is found, for instance, that has an effect on the heart like that of digitalis. - Making Garbage Profitable te! these days of strenuous conservation New York city calmly spends three million dollars a year for dumping five million dollars’ worth of garbage into the sea. And yet, methods of garbage reduc- tion have been improved until now it is possible to obtain a high percentage of valuable products from garbage. It will yield at least four per cent of grease and fifteen per cent of tankage. At present prices grease is worth about four- teen cents a pound, and tankage is worth fifteen dollars a ton. If New York would build a reduction plant, garbage would become profitable. Oil from Corn | a people know that corn contains oil. A valuable cooking oil is now being recovered from corn. it is really a by- product of the manufacture of certain stable corn products. With the great corn crops in this country, tremendous quantities of corn oil can be manufactured. This oil is a very good substitute for cottonseed oil. Many bak- ers now use cottonseed oil because the production of corn oil fluctuates. How Lightning Kills UCMBERS of cases of death by light- ning have failed to reveal any direct effect of the passage of an electric current through the human body. The evidence indicates that death was caused entirely by shock. The result is psychological rather than physical, the shock inducing heart failure or other organic disturbances. - Sometimes strokes have been fatal to a mother although the child in her arms was unharmed. Persons under the influence oi a drug or intoxicated seem to escape. This seems to indicate that the psychological element is an important consideration. Making Soles of Rubber HERE are about one thousand shoe manufacturers in this country, and their average daily output of shoes is rated at more than two million pairs. What a huge supply of leather is demanded, if all of these shoes are to have leather soles! But in the past five years attempts have been made, with more or less success, to find a suitable substitute for leather. Soles made of fiber and rubber, molded to the de- sired shape, give the most promising results: It is estimated that there will be a daily ‘demand :for at least 686,466 pairs of rubberized soies, if the desires of the public are met by enterprising manufacturers. Only about three and one half per cent of this demand is now being met. Various fiberized soles have already demonstrated their worth, both in army and in civilian life. The man who would walk. on a smooth roof without slipping, who would climb rocky ledges, and who would find comfort in walking can testify to the value of the composition sole com- pared with that of leather. Noxious Gas in Mines wee an explosion occurs in a mine, there is often the urge of immediate rescue of men who have been imprisoned. Following the catastrophe, some parts of the mine become choked with noxious gases, and through these the dangerous trail of the investigating party may lead. It is then necessary to equip the men with an oxygen-breathing apparatus, and the maximum distance that can be traveled with the best supply is five thousand feet. That is, one can travel safely two thousand five hundred feet and back on a level stretch unencumbered by obstructions. But danger lurks for the men who try to go farther than their limited supply of oxygen will permit. Three miners were recently killed in trying to travel two thousand four hundred feet on a supply of oxygen that was intended for a duration of forty-five minutes. The slope down which they lugged the forty-pound ap- paratus had a twenty-five-degree incline. They probably made good time going down, but the climb back with their heavy outfit was too much and the supply of oxy- gen was exhausted before they could reach fresh air. Are There Other Universes? 1* there one great universe at least ten times larger than was formerly believed, or are there numbers of island universes similar to that to which the sun belongs? Astronomers are seeking the answer. Some contend that the Milky Way contains virtually all of the stars, star clusters, and nebulae, forming a gigantic circular disk 30,000 light-years across and 3000 light- years thick. Light travels 186,000 miles a second, so that a “‘light-year’’ is an enor- mous distance. Modern investigation seems to indicate that there is a galaxy of stars ten or more times larger than the Milky Way, ana that beyond this galactic universe can be dimly seen, through the largest telescopes, innumerable other “island” stellar sys- tems. These distant universes are so remote that only a mere trace of them can be discerned. Fruit Butter by Vacuum E are all more or less familiar with apple butter; but apricot, peach, quince, and grape butter are known only to those of us who have lived abroad. Euro- pean immigrants coming to this country hanker after these fruit butters, and the de- mand for them has led to the development of a new vacuum process for making them. Undersized or overripe fruit is used for the purpose. It is washed, crushed, pitted, and then sent on to finishers, who remove the skins and tough fibers. The resulting 80 Popular Science Monthly pulp is diluted with water, and is pumped into storage-tanks, whence it is fed to a spherical vacuum-tank. The tank is filled and then closed. Steam coils within revolve and agitate the watery pulp, while small brushes attached to the coils scrape the bottom to prevent burning. Because of the heat the water constantly evaporates and the butter forms. The vapor passes off through a pipe at the top of the tank and the butter is drawn off at the bottom. The Crows in Oklahoma T= cawing black crows prevalent in Oklahoma during the winter have recently been the subject of extensive in- vestigation to determine the extent of the damage they do. It was found that during the fall and winter months the birds feed principally upon grain, peanuts, and pecans, when these are available. At other times animal offal, weed seeds, and insects are their diet. It is estimated that at least ten million crows remained in the state during the win- ter, and that one bushel of grain daily was consumed by each thousand of the birds. This makes a grand total of $1,200,000 loss in grain during the winter months. A number of methods of getting rid of the birds have been contemplated, one of which is shooting them as a winter sport. On Which Side Do You Sleep? - A CCORDING to Professor Hans Guen- ther, 28.5 per cent of us sleep on the right side, 22 per cent on the left side, and 14.5 per cent on our backs. When we lie prone on our abdomens, it is, as a rule, because we are sick. The same holds true for other unusual positions. Why do most of us sleep on the right side? Probably because the stomach can empty itself better in that position. lf the habit is formed of sleeping on one side, it is probable that in time the body will lose some of its symmetry. Barbers know that the growth of the hair on the head and the chin is retarded on the sleeping side, presumably by pressure. A Prehistoric Niagara? eplamnanieee aig conducting the work of excavation for the new Welland ship canal have unearthed what seems to have been a prehistoric Niagara. The ledges that have been uncovered in a width of 400 feet are in steps of about 25 feet total drop. Then for one hundred feet the rock has a sharp downward slope to what must have been the brink of the ancient waterfall just seventy-five feet below the crest of the uppermost ledge. At this point the great current leaped into a chasm hundreds of feet below. Unmistakable signs of wearing through the action of water are indicated by the surface of the rock. For countless cen- turies this prehistoric Niagara must have cut its passage from Lake Erie to Lake Ontario, and then for countless years must have remained buried under the accumu- lation of ages. Pamiular Smoenro Manthh,

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December, 1920 Multiplying Man’s Power by Machinery This automatic lathe, with one setting up of © a pair of magazine tool-holders, will make as many cuts as would five machines with but one cutting-tool each Placed in position, this automatic lubricator for the flanges of loco- motive or car wheels will protect them and the rails from excessive wear in rounding curves Two men operating this dump- ing-truck of forty-three cubic feet capacity handle as much coal in a given time as was formerly handled by six labor- ers, each using a wheelbarrow with four cubic feet capacity With this staybolt cutter one man can do the work of twenty-five-men cutting off staybolts with chisels and hammers. clip 1200 bolts to the right length. It is per- fectly balanced and its position can be changed by a touch of the operator’s hand This electrically actuated routing machine is employed for cutting the grooves for steps, shelving, window-frames, and other purposes. It does as much work in a given time as a small army of men with saws and chisels In an hour it will Spot-welding machines were introduced dur- ing the war rush at the shipyards. They increased the production of ventilator cowls Automobilists will be in- terested in this new timer grinder driven by hand or engine power. It weighs only seven pounds and may be easily attached either to a shop bench or to the running-board of an automobile What the yard locomotive is to the freight-yard of a railroad, a truck like that shown in this picture is to the:factory, shop, or freight depot: It is strong, easily operated, practically fool- proof and will haul big loads A most useful help and time-saver in a shop or mill, especially where heavy loads must frequently be moved, is a platform truck, equipped with a small, powerful crane operated by a small motor

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er eo It seems almost incredible that the small caterpillar tractor shown here could pull the truck loaded with a huge ten-ton tank over rough ground; yet it ac- complished that task, apparently without the slightest difficulty This grease-cup has no detachable parts to lose. The spring- metal plunger exerts a uniform pressure and makes the cup suitable for grease or oil / | Popular Science Monthly Do You Own a Car? There is always something everywhere inventors are Take a test-tube of glass, put in it a few discarded phonograph needles. and some., gasoline, and. you have a spark-plug cleaner. Put the plug against the _ opening of the tube and > shake it — Here is shown how close-ups of automobile scenes are made with the motion-picture machine. operator is placed with his camera on a paeem's in front of the radiator The Carry a small horseshoe~ magnet in your tool-box. It is very convenient to hold your small trouble ‘lamp on motor, fender, hood, or any other steel or iron part of your automo- bile while making repairs This tiny automobile, the property of a “movie” star, is probably the smallest ever built. It has a twin-cylinder motorcycle engine and can make eighty-five miles an hour bs ih inde ae 1 fr a eS ek ioe i Throughout Great Britain gasoline—or “petrol,” as it is called there—was until recently. obtainable only in two-gallon tin cans like those shown in the picture. Ameri- cans are now introducing modern tank stations With the extension tire-rack attached ‘to the one-tire rack fur- nished with your car, you may carry either one tire or two on the rear of your auto- mobile 82 How much did you pay for your car? Never mind ‘how much! Now, look at the magnifi- cently equipped automobile shown in the picture. With all its accessories, it cost its owner a trifle more than $25,000 Popular Science Monthly

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December, 1920. Find New This fan- belt is made of fiber, leather, and metal. The links of fiber and metal bear the strain of the pull, while the leather takes care of the friction A tool-chest that may be carried on the running-board of the automobile. When opened, its door, supported by braces, forms a convenient work-table Ideas Here new in the automobile field; contributing novel features don’t do it. There may be a motorcycle officer watching for offenders from behind a wall or tree with a periscope All the comforts of home, including sleeping quarters, kitchen, pantry, and sitting-room, are combined in this automobile equipped for overland tours PERE You may think it safe to do a little speeding, but MARGUETTE 40827 In an industrial parade in the Middle West this truck, with its unusual load, created great inter- est. It carried a half-size model of a freight-car, complete in every detail, resting upon a miniature track This picture shows a new tire vulcanizer recently placed on the market. Its construction is unusually simple, yet the appa- ratus is effective and durable Tools that have become greasy and dirty, when used in repair work, may be quickly cleaned by placing them on the grating of an Oven and burning off the grease December. 1920. TE pate Here is an emergency repair-truck, equipped with lathe, drill-press, grinder, welding apparatus, forge, a separate motor, and all necessary tools; it is used by big concerns to repair trucks that have become disabled 83 When this automobile lock is closed, it fastens the gears jn reverse position and clamps on the emergency brake. The car can neither be driven nor towed without breaking the lock

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With this hand reamer you can true up the bearings of your crankshaft on the road if necessary An Emergency Reamer VERY automobile repairman has a demand for a portable tool with which crankshaft bearings may be trued up in an emergency in the car or on the bench. Truing up a set of. crankshaft bearings by turning on a lathe is a more costly and slower method. The hand reamer shown in the illustration consists of a handle and split locking-ring in which the cutting tools are inserted. Its maker claims that with the tool an average mechanic can true up a worn or out-of-round crankshaft bearing to within an accuracy of less than one thousandth of an inch in approximately twenty minutes. Popular Science Monthly Watermarking the Radiator MONG the newest innovations in the marking of automobiles for identification is a “‘watermarked’’ radiator. The process by which the watermarking is ac- complished was invented and patented by L. G. Hanmer, of New York city. The watermarking is done by increasing the size of certain predetermined cells in the radiator by an expansion process after the cell structure has been as- sembled ready to be dipped into solder. This difference in the sizes of the cells gives the impression of the light and dark cells that makeup the trademark or monogram. the actual expansion so of the cells is ex- panded, the remain- der or back half of the radiator struc- ture being entirely homogeneous. Under certain light conditions and from certain angles, the watermark is scarce- ly discernible; while under other. condi- tions it appears very clearly. One is enabled to judge for himself of this alternate visibil- ity and invisibility of the watermarking by moving the illustra- tion quickly from one angle of vision to another at different distances. In of the cells, only the front half inch or Have your radiator front marked like the one shown here to make your auto- mobile more attractive and easier for you to identify Saving Time in Coupling Tractors and Trailers N the four-wheeled trailer the entire trailer load is carried on the four trailer wheels, with none of the trailer load supported on the framework of the pulling vehicle, as is the case with the two-wheeled semi-trailer. The loss of time in connecting the four-wheeled trailer has occurred in backing the truck up to the trailer, so that the bolt or jaws of the connect- ing drawbar might fall or lock. into place. This operation has required two men, the truck-driver to back up his truck, and a helper, to guide together the drawbar attached to the trailer with the locking member on the truck. There was always danger of the helper being mashed be- tween the rear end is a lever pivoted to one side of the truck frame at the rear. The length of the lever is such that when it is swung toward the center of the truck, it carries whatever is fastened to it directly into the jaws of the waiting coupler. Instead of having to back his truck to within an inch or two of the forward end of the trailer drawbar, and then have a second man make the connec- tion, the driver merely backs his truck to within twenty inches of the proper coupling distance. Then he dismounts, places the front end of the drawbar coupling link over the stud at the end of the pivoted lever, returns to his seat, and backs his truck. The lever automatically carries the coupling link into the jaws of the coupler on the truck, which lock. The lever is thrown free from the coupling and held out of . the way by a spring. The whole operation may be com- pleted in about two minutes’ time by the truck-driver. While the ability of any wheeled or other vehicle to pull more than it can carry is well known by the every-day examples of the railroad train or the tug-boat, the application of this prin- ciple to the motor-truck and trailer has not always worked out satisfactorily because of theloss of time in connecting and disconnecting. This problem has of the truck and the front end of the trail- er if the driver were careless or there was any misunderstand- ing as to signals. Both of these ob- jections can he over- come by the adop- tion of a new form of safety coupler, as shown in the ac- companying illustra- tions. The new fea- ture of this coupler When the coupling is completed, the drawbar is automatically dis- connected from the guide lever 84 This shows the drawbar engaged in the lever which ‘guides it to the coupler been solved in the case of the semi- trailer by the adop- tion of the self-cen- tering fifth wheel and similar devices. It was not, though, until the advent of this new coupler that any apparatus had been devised to cut the loss of time in connecting and dis- connecting a four- wheeled trailer. Paonular Seienre Moanth)a

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December, 1920. This Oil-Cup Works Automatically NE of the latest designs in oil-cups is automatic in operation and yet occupies no more space than the ordinary grease- or oil-cup. The cap is hinged, not to the side of the cup, as might be expected, but to a central valve inserted in a cup-shaped piston. In outward appearance the cup is much like any other. . As soon as the cap is removed, the difference becomes apparent. When the cap is opened, the piston is forced upward by a coil- spring underneath. This unseats the center valve and permits oil to be injected into the space below the piston from an ordinary oil squirt-can. When the cap is closed, the piston is forced downward - against the compression of the spring by the center valve by reason of its being hinged to the cap. This forces the oil down into the bearing to be lubricated: at a pressure of between two hundred and three hundred pounds to the square. inch, or sufficient to force all foreign matter fromthe bearing. The oil. is, “automatically fed

In one minute you can change your touring-car to a limousine, protecting you from wind or rain A Convertible Automobile Body PROMINENT English aviation expert has developed a unique type of convertible automobile body. This body is simplicity itself. Aside from a folding top, the rear quarters of which are closed, it has a three-section glass part through the center valve by a felt «<n e that completely encloses the sides of the body, when un- wile ok the’ tr at e of a few drops 2 “the nit — py “i folded. This glass portion folds into the space of the center day, thus assuring ‘constant-lubri- filled. When closed, it section, just as the familiar triple mirror does, and then the cation, even though the cup‘is not. feeds oil to the bearing three plates swing down into a compartment provided for touched from the time it is first utomatically under them in the side of the body between the doors. When filled until it has become empty. pressure unfolded, each glass panel fastens securely in its respective position, the side sections to the doors and the central part to the top. It is claimed that the transformation from open to closed form or vice versa, can be accomplished in about sixty seconds. epi +t ; s

The Paving Machine with Caterpillar Traction HE latest adaptation of the cater- pillar type of creeping tread to a commercial: product is on a street- paving machine. Because the creeping tread is- interchangeable with the ordinary wheel traction, the machine takes on a dual purpose in that it can be used in countries having alternate dry and wet periods. The change from one form to the other may be made readily. The creeping tread is of the tri- The Tool that Tightens: Anti-Skid Chains *~ SLOTTED J. (HOLDS Tike CHAIN LINKS)

OMETIMES, when a motorist has

angular type with three wheels inside, This combination tool may be rege? a eT ae vig tven two at the ends and one in the center at used for tightening automobile difficul ae " the top, where it serves as a tightener chains or for removing a tire- ifficult matter. to close the two ends The triangular shape of the teenie casing from its rim of the chain without getting out every screwdriver or pair of pliers he has in his toolbox. This is because the chain must be stretched evenly around the tire and fitted fairly snugly before the snap fastener can be closed. ~Thé riew tool shown herewith was designed. for the very purpose of mak- ing this task easier. It consists of a handle with two pivoted jaws at one end. The ends of the chains are slipped into the slots in the ends of the jaws, and the handle given a twist, when the two ends of the chain are brought together for easy attach- ment. Aside from this use of the tool, the curved end of the handle may also be This new type of street-paving machine can be changed from employed to remove a tire-casing from a wheel drive to a creeping-tread drive in a few minutes its rim. 85 permits the bucket to swing close to the machine with- %. out coming into nee contact with the Nid eee treads.

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THERMOSTATS The rapid rise in temperature causes the thermostats to ring a bell before a fire in the room gains a dangerous start Trapping Fires Automatically GES .ago primitive man worshiped fire. In the world to-day there are the remnants of a fire- worshiping race, but to the civilized world fire is both a blessing and a curse. When it gets beyond the control of man, it is a demon of destruction. Ten thousand lives and $250,- 000,000 in property are annu- ally sacrificed to the fire demon in the United States. Another $250,000,000 is annually spent to keep up the necessary appa- ratus to fight fire. Aspark, scarcely visible, may start a conflagration that 7 sweep away # whole city. tA fire de- tector that promptly sounds the alarm would agar enable a quart of ‘”* water to accom- plish what scores of powerful streams from the hose might fail to accom- plish a few hours later. An automatic fire-alarm that aera upon the principle of the rapid in- crease in temperature due to a fire in the room, instead of depending upon sufficient heat to cause the fusion of soft metal alloys, has proved itself valuable in giving notice of a fire before it gets beyond its easily extinguishable stage. Ordinarily a fire-alarm depending upon alloys, soft solder, bimetallic compositions, etc., requires a rise of temperature of from 110° to 250° F. By the time a fire has raised this-degree of heat it is an agent of destruction. With the instrument shown here, the burning of a newspaper in a room having a floor space of five hundred square feet is sufficient to cause the alarm to be given. It operates the instant the air close to the ceiling be- comes heated at the rate of 4° F. a minute, AIR VENT Popular Science Monthly Insulator in the Dark—Conductor in the Light N insulator is a substance that will not permit the passage of an appreciable amount of electric current. A few substances are perfect insulators in the dark, but when light falls upon them, their electrical resistance changes rapidly. In some instances, current is allowed to pass with perfect ease. Such substances are said to have photo-electric prop- sitiiniaeie erties. The element THALLIUM. selenium has very COMPOUND marked photo-elec- tric properties. When ‘} it is caused to form meneame part of an electric { snes CON- circuit, no current will flow while it is in the dark. Imme- diately a light fails upon the selenium, its resistance is low- ered and current flows. Advantage has been taken of this property in the perfection of burglar alarms’ and _ the __ PLUG, CONNECTION =. at transmission of pho- tographs over wires. A substance has The light-sensitive thallium compound is mounted in a glass tube. It is far more been discovered that sensitive than selenium and is far more sensitive should prove of great value photo-electrically in studying faint variable stars than selenium. This substance has been called thalofide. It is composed of the ele- ments thallium, sulphur, and oxygen. It was dis- covered by T. W. Case, a physicist, living in Auburn, New York. The thalofide is mounted on a The heat inflates a thin @uartz disk and placed in an evacuated red glass diaphragm that closes an bulb. So sensitive is this cell that its electrical electric circuit, which resistance will drop fifty per cent when it is-exposed rings a bell. The ordi- to a light source of one candlepower at a distance nary heating of air in a ; ae onan “wh Get ones ee of one foot. If its resistance were ten thousand alarms ohms in the dark, it would fall to five thousand upon exposure to this small amount of light. Harnessed to His Car, Sictree reosey reac : He Won’t Fall Off: F you are atrolley-car traveler, you will appreciate the hardships and risks of a conductor’s lot. He must climb around a step full of people to collect his fares, hold on by one hand, and constantly run the risk of being thrown off. But John Udall, of Weston, On- tario, has invented a protective har- ness that should do away with the dangers of a conductor’s job. This * harness is strapped around the con- ductor’s body and then attached to a: chain. The chain has a small carriage at its upper end that moves in tracks. As the conductor walks along the step the chain moves with him. : Should he be hurled off the step, He won't be hurt if he is thrown off he will swing at the end of the the step. He is harnessed to the car chain and remain unharmed. 86 Povnular Science Monthly

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December, 1920 aan Icy BRITANN ECTVENTHA EL vest ora >, a Se eS re ne et WOMENS £ ~ pte lA ee. Wang, Shea? a an he & elite Paces. he he ee. ee ei a Bal ¥ 2 BC de Coa Ns ao te Fy thee . « ened oi, raged ta eR he i é ; r Pe se 7 a I oe é: en Me occ ae Lae ne! id wo , Oe a 4 + ao a HAT is this New Idea that saves $65 and brings the Encyclopaedia Britannica easily within the reach of thousands of new homes? Think of it! $65 saved on the very latest edition of the genuine Encyclopaedia Britannica—the famous Reference Library you have al- ways wanted. Yes, this tremendous sav- ing is made possible through this New Way in Book Making! For this New Way has produced the “Handy .Volume Issue”—just as hand- some, even: more handy—and page for page, picture for picture the same as the ‘“‘Cambridg2 University Issue’’—yet at $65 less. But this big saving is not all. Just $1 brings this great 29-volume work into your home. Small monthly payments (amounting to only 14 cents a day) make the rest easy for you. So that now, through the Néw Way in Book Making, the won- derful Encyclopaedia Britannica is within reach of everyone! Only $1 down brings this world-famous Reference Library into your home! The Encyclopaedia Bri- tannica furnishes you with an interesting teacher on any subject you wish to read about—generally a famous authority whom the whole world knows, and who tells you, clearly, simply and thoroughly, just what you want to know. The Britannica gives you the answer to the thousand and one questions that newspapers, lec- tures, sermons and books prompt in your mind. It helps you push yourself ahead in your business and also gives you valuable information on busi- nesses relating to yours. In its almost 29,000 inter- esting pages are the facts that your children need to know—and are always asking for. It puts you in touch with the interesting people of the world, with their work and their ideas. It makes every- thing you see, read and hear more interesting and gives you hundreds of live topics to talk about. In short, the Encyclopaedia Britannica offers you ; apa CHEN) sara ENCES EncrcuameD NC sarang | TANNeN BRAN % niventn c &. DITION n ~~ i lt 2 ‘ eR dS A dea « he ad ia a at ~via, New Idea Saves You on Encyclopaedia Britannica Now Easy to Own the Britannica No need to hesitate any longer about the Britan- nica! No longer need you déprive yourself of the famous reference work you have heard about since a child and have always wanted. . Nothing the world has ever learned or that you want to learn ever seems beyond it! The history of all nations, the geography of all countries, the story of the development of all religions and philosophies, all sciences and inventions, the principles of mechanics and engineering, the salient features of art, litera- ture and industry—virtually a daily useful library of handbooks on architecture, music, business, sewing, foreign trade, agriculture, chemistry, education, electricity, interior decorating, languages, physics, law, politics, manufacture — everything. And now you can easily own the very latest edition of this famous reference work—in a form that would do honor to a millionaire’s library! Through the New Way in Book Making this “‘Handy Volume Issue’’ saves you $65. Why 140,000 Families Are Proud Owners! How does this New Way in Book Making give you exactly the same edition—page for page; picture _ picture—yet at $65 less? _ How could it‘ put 44,000,000 words, 41,000 separate articles, one-half million indexed facts, and 15,000 illustrations and maps—yes, put all these in clear readable form into 29 beautiful “‘Handy Volumes’’ which altogether weigh only 45 pounds? ly $1 Do that powerful capability of talking, thinking and acting from solid | acts which no person can dispute. Mail Coupon for Booklet Send no money to us now! Let us send you, postpaid, our interesting booklet explaining how easy it is now to own the very latest edition (the eleventh) of the Encyclopaedia Britannica. The coupon is all you need send now! Whether you are a business man, lawyer, clerk, doctor or farmer, a nurse, housewife, business woman or teacher—no matter what your field of endeavor, how old you are or where you live—you need the Encyclopaedia Britannica. rn now how you can save $65 on the “Handy Sears, Roebuck and Co., Chicago 8 No type was set for this ‘Handy Volume Issue.” Thus was eliminated a task that would have taken 55 typesetting machines over seven full months! Instead, a separate photograph was made of each of the 28,708 pages of the larger paged ‘‘Cambridge University Issue.’’ Each page was reduced. in size to 85% by 6% inches—the convenient and practical size of the ‘“‘Handy Volume Issue.”” The margins were made narrower, but this kept the type clear and readable. .Then copper printing plates were made from these clear new photographs. And at one stroke was saved the entire, tremendous job of setting again in type over 44,000,000 words! But that was only one of the savings brought by the New Way! 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Learn how $1 puts the entire 29-vol- ume set into your home . for examination without obligation to buy—and how you can make small monthly payments amounting to only 14 cents a day. Mail Coupon for our interesting 136-page illus- trated book. Do it today. Sears, Roebuck and Co., Dept. 19L, — Til, Gentlemen— Please send ‘me tpaid your interesting illustrated 136- e boo ‘a ing about the “Handy Volume Issue” of the Encyclopaedia Britannica—and about your $1.00 down, a | monthly payment plan This request obligates me in no way. Petes 66 sic ete che ted sameuepodesoudraens nag Bo: ciety tenance eel NGibs cccens OOMBis as ovnes Street ING sc oe vc Sésivebceweredevcccpebdodevene® °

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See aaa Sen I Popular Science Monthly Gliding over the frozen and smooth surface ofa large pond, lake, or river with lightning speed in a sled with motor-driven propeller is a fine winter sport indeed equally delightful for young or old ~ How te Build an Icemobile Make your iceboat. independent of the fitful power of the wind HE ice-yacht is in its element in a brisk wind; when the air is calm it has to remain at a standstill. That is the one disadvantage of sail-pro- pelled: boats operating upon either water or ice. But for the man who can procure a small engine, the freakishness of the elements can be discounted, and high speed attained upon the ice—‘“blow high, blow low.”’ Independence from atmospheric con- ditions adds to the pleasure derived from this sport, A typical ice-boat body i is used for the foundation of this icemobile and an air propeller is. utilized.to drive it. The air propeller is used for many rea- sons: because it eliminates the problem of traction upon the ice, gear-shift and differential complications, -and offers a simple means of driving direct- ly from the engine. With a propeller of suitable proportions and an engine capable of: giving sufficient speed, much exhilarating sport may be en- joyed on smooth ice. Common sized lumber and standard iron pipe, as well as the standard Ford supplies and specifications, are designed to be used throughout. This means that the cost is kept low and parts are readily obtainable. The engine is the only costly part. But if the second-hand automobile market is watched closely, engines possibly past road usefulness may be purchased at a trifling cost. They may be used in this craft to advantage, in spite of small defects that would render them undesirable as automobile engines. Of course, the better the engine, the better the results. The drawings are made to the By E&. B. Rotbing ai een of.a Ford: engine, but any other engine may be used. The engine-bed’ and power-transmission arrangements will have to be altered somewhat. However, this i is not diffi- -cult. It is best to: purchase the propeller, as.most amateurs will find it a-su prisingly cifficult task to make one. The Backbone : This i is the foundation of the entire * craft and also serves as the engine- bed. ‘The main part is composed of two lengths_of..clear spruce or white pine 15 ft. long, 8 in. wide, and 2 in. thick. Five ft. from one end, taper the two pieces down to the ‘opposite end, so they measure.4 in. wide. Next insert a piece of clear grained SIDE ELEVATION TILLER ROD CONNECTING \ RUNNER BRAKE LEVERS .) | *f PLANKING) SUPPORT TILLER = at ES = an Bb ii 5 aks ft - c= | ee 2 i TILLER ROPES TO STEERING PUST q ss PLAN R Don’t you think that the icemo- bile, of which two views are here oak or ash 20 in. long by 3 in. wide by 2 in. thick between the two 8-in. ends of these backbone timbers, and secure it by two 8-in. lag-bolts ‘inserted threugh the sides of each timber. The oak piece should come flush with the bottom edges of the long timbers. Reenforce their union by bolting a metal plate to each piece at both sides , (underneath). This is shown in Fig. I, and.leaves a space for the radiator 5 in: deep. Five feet in the rear of this front cross-piece insert a sécond piece A 20-in. long and 8 in. wide, fastened by lag-screws.in the same way. Now cut out a wedge-shaped piece of hard wood 2 ft. long and_of suitable shape to fit between the 4-in. ends of the two sides when they are sprung together against it.in the rear. The smal] end of. the wedge should be about 2 in. thick. Bolt, the sides to it as. shown. Three feet back of timber A insert a third piece (8) of hard wood 8 in. wide and 2 in. thick and long enough to spring the sides out in a gentle curve toward the rear without forcing them apart between the two front cross- pieces forming the engine-bed. Use lag-screws to fasten this also: Bore a 1-in. hole in the wedge block 18 in. from the rear end for the rudder- post to rotate in. Next build a platform of matched boards 5 ft. long and 3 ft. wide upon the rear of the backbone. Lay this lengthwise and support it by three cross-timbers of 2 by 3 in. mortised into the top edges of the backbone timbers so as to lie flush with their shown, would make a trim little craft? top edges. The rear end of the platform 88 ee Fees [on ee py gece ) Se

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December, 1920 Kodak as you go. Eastman Kodak Co., Rochester, N. Y., Zhe Kodak City

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bears against the forward end of the wedge. The sides is a support for the forward runners, and is composed of a piece of lumber similar to the stock used in the backbone. It is 8 ft. long, 8 in. wide, and 2 in. thick. The runner guides at each end consist of two blocks of 2 by 4 15 in. long bolted to the under side of the cross-plank with carriage-bolts. (See Fig. 2 and side elevation.) Bore a hole through the 7 GUIDES OF 2x4 METHOD OF ATTACHING FORWARD RUNNER FIG! FIG2 METHOD OF ATTACHING RADIATOR TO FORWARD END OF BACK BONE —. . FiMBERS be == /U-SHAPED HANGER ka t = a SHOWING HOW CROSS-PLANK IS ATTACHED TO BACK-BONE WITH STRAP-BOLTS FIG4 CASTELLATED NUT PIVOT BOLT FIGS NOTCHED FOR STRAP BOLT DASH ace eae on | STEERING RUNNER AND DETAILS =e = 3 END OF r ENGINE 215" Nut |b Sd = rn | a | ..] UNIVERSAL JOINT aa tre = = KNUCKLE MALE END NGINE BED FIGS R T ——- / SHOWING HOW UNIVERSAL ENGINE FRAME BOLT HOLE THRUST “ JOINT 1S USED TO BEARING TRANSMIT POWER TO FIG6 PROPELLER SHAFT Study the illustrations, Figs. 1 to 6, carefully for the details cf construction of the framework bearinz the engine and of the method of attaching the runners center of the blocks for the pivot bo!t in the runners. Insert a strong eye- bolt in the rear edge of the cross-plank close to each pair of runner guides. The two forward runners are made of oak 30 in. long, 4 in. wide, and 1% in. thick. The forward end is shaped similarly to a sled runner, and the bottom is shod with half round strap- iron. Bore a hole, to match that in the guides, in the center and 1 in. from the top édge. Pivot them to the space between. the guides with 5¢-in. bolts, locking.the nuts. The _ steering runner is of similar dimensions and construction, except the mounting. The hole is bored 2 in. below the top edge, and is_ pivoted between the. legs wrought-iron hanger. This can be made by any blacksmith. Use a . ¥%-in. bolt for pivoting. Drill a 1-in. hole in the shoulder of the hanger, and insert a 1l-in. steel bolt to act as the rudder-post. Square the top end of this bolt about 2 in. down to take the tiller. The rest of the assembly is shown in Fig. 3. Insert it through the hole in the backbone and take up on the adjustment until the rudder turns easily but not loosely. The spring shown tends to keep it at a tension and to some extent acts as a shock-absorber. The tiller consists of a piece of oak 2 ft. long, 4 in. wide, and 1 in. thick, with a square hole in the center to fit over the squared end of the rudder- of. a U-shaped - _ joint back in place. post. Tnis is held in place by a large cotter-pin inserted through a hole in the post. Provide two holes in the ends of the tiller for the steering-ropes. The body is assembled by clamping the cross-plank to the front of the back- bone by means of four strap-bolts, as shown in lig. 4. The plank:is set under the backbone, the center of the plank coming 20 in. from the front of the forward cross-piece of backbone. Use washers and nuts under the plank, and take up on these occasionally so no undue play will occur. Place two wire stays with turn-buckles between the ends of cross-plank and the sides of backbone as shown. These should be tightened occasionally. Place a dashboard, made of oak and kraced as indicated, just forward of the front end of the platform. This is used to support a wind-shield of any desired style and as a support for the steering column. _ Two bucket seats of conventional design can be placed upon the platform staggered as shown, so the driver will be slightly forward of the passenger. ‘These can be tipped slightly back if Cesired. Engine-Bed and Power Plant The engine-bed is composed of the forward portions of the backbone timbers and the end cross-piece.. The dimensions are shown in Fig. 45. This is the right size to take a'Ford engine without alteration. The two side supports bolt to the frame 31 in. from the front, and the front support bolts to the front cross-piece togéther with the crank bearing. Remove the engine from the chassis, and cut off the drip-pan just behind, the forward support. First mount .the radiator between the sides exactly 45 . it was in the chassis (Fig. 1). . Then set the engine in place on the. bed. Strap the crank-bearing (Fiz. 1) to the cross-piece in the exact center, and include the forward engine support with it. Then bolt down the side supports, using bolts to ¢o through the timbers and bolt underneath. Next, set up the dash, 31 in. back from the inside face of radiator. Support this by two triangular sides of sheet iron (as shown in the side- clevation sketch) to hold it rigid as well as to protect the engine trans- mission. Secure the top of the radiator to the cash with the tie-rod. All other engine installations are made just as in the original chassis. Remove the universal joint and alter it as shown in Fig. 6. This consists of cutting off the shaft- housing and shaft just below the drive- shaft bushing. About 2 in. of shaft should project from’ the housing. Place on a thrust bearing a suitable sprocket, and secure with a lock-nut. Before doing this, however, cut a hole in the. center of timber 4 in line with the drive-shaft in the engine trans- mission, and then set the universal Bolt it to the 90 Popular Science Monthly timber through the holes in the housing shoulders formerly occupied by the rear radius rods. Take care that the sprocket -runs perfectly vertical and at right angles to the engine-shaft. The propeller-shaft runs in a frame mounted directly over the engine (tig. 7). This is made of 1-in. iron piping, and can be either made square by joining the sections by elbows or can be made more upright by using 45° connections. This is optional. This frame supports, a length of 1)%-in. pipe running horizontally and directly over the engine. Inside each end of the pipe is forced a shouldered bushing, 1 in. inside diameter. A pair of metal collars fit around each end of the pipe and also hold the flattened ends of the standard ends between them, as shown. Bolt the collars and frame ends together. Insert an oil-cup in the top of each top collar and extend it down through the bushing. The length of this pipe and height of the standard will depend upon the length of the shaft and the length of the pro- peller. The propeller mounting is shown in Fig. 8 and need not be described in detail. The end of.the shaft sup- porting the propeller must be squared and have a shozlder back of the rear disk of the mounting. Between the rear disk and the bushing is a thrust bearing. The nut on the end of the shaft must be cecurely locked. Use six bolts to connect the disks. They must be long enough to pass through the hub of the propeller. The shaft must be of a length to allow the propeller to clear the radiator -cuP OIL-CU corre TIMBER v a XY STEERING BLOCKS: FF © coLuMN BUSHING : FLATTENED * METHOD OF WASHER aoe \ FIGS SUN proms SHAFT CENDARDS AND ARRANGEMENT ANGLE |RON OF BEARINGS TAC OrLeR , MACHINE 6 SCREWS TILLER ROPE LEVER ON STEERING POST Eee > FIGS 0 WASHERS DETAIL OF SHAFT AND PARTS DETAIL OF BRAKE ARRANGEMENT FIGII Details are given here of the propeller- shaft bearings, the method of attaching the steering column, the power transmis- sion by sprocket-wheel, and the brake by at least 3 in. and to allow the sprocket on the opposite end to come Cirectly over the sprocket on the en- cine-shaft. The propeller-shaft is 1 in. in diameter. When the shaft, bearings, and stand- ard are all assembled, bolt the sides of the standard to the sides of the engine-bed, as shown, being careful to get the propeller-shaft in exact line. Also be sure that the shaft is high enough so that the propeller tips will clear any obstructions. Use sprockets and chain heavy

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_ December, 1920 Where Mechanical Genius has solved the problem of LIGHT WEIGHT and DURABILITY N THEINDIAN Scout, INDIAN engineers have given to the motorcycle world a powerful, sturdy and com- pact machine that is extremely light in weight and that has already established itself as one of the wonders of motorcycle development. But, while light weight was the guiding line of Scout construction, it did not tempt INDIAN engineers to sacrifice durability. In every mechanical member of this newest INDIAN wonder from the unit powerplant with its unusually high horse-power output down to the’ pressed-steel mud-guards, there have been incorporated the same factors of safety that, for years, have made the name Powerplus a by-word for trustworthiness. ’ Go to your INDIAN dealer today and look over this latest Indian mar- vel. It will appeal to your mechanical sense because it represents the very latest achievement of the world’s foremost motorcycle engineers. It will appeal to your sporting sense because it is a thoroughbred. HENDEE MANUFACTURING COMPANY Dept. 38 Springfield, Mass. The Largest Motorcycle Manufacturers in the World Indian Scout Model G-21 91 ce

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ae eee Published in the interest of Elec- trical Development by anI nstitution that will be helped by what- ever helps the Industry. A saving you can't afford Building a home or a factory is every bit as hard as building a derby hat. But man, while content to pay for the hatter’s skill, has a lurking desire to plan his own structures, to play the roles of architect and director of construction. And a home made building is generally about as dashing as a home made hat. Interesting, to get out pencil and ruler and to cover sheet after sheet with designs after our own ideas. But an expensive diversion. Cheaper to line up a set of Bohemian vases and throw rocks at them. It’s a shock to finish the house or factory ~ and find we’ve forgotten a point in fire pro- tection that costs a thousand dollars to fix. There are pitfalls, discouragements and re- morse for the average owner who builds alone. Enter the old adage, ‘‘Cobbler, stick to thy last.”’ oe At a'small fraction of the cost of our own ill-starred experiment the best engineering brains in the country will work for us. They will do the job and do it right, down to the last electric light and switch. Whether it be a home where artistry, building skill and liveability are to be fused into one; whether it be a problem involving a most specialized department in a technical industry—the architect and the engineer bring a seasoned and unbiased judgment to the task. After all, how much better to set two minds at work on the problem—one the architect or engineer, and the other yourself —each contributing to the solution. And this is aside from the economy of it. estern EjJecfric Company No. 13. Western Electric—an organization whose products and services apply alike to all fields where electricity is used—in the power plant, in the shop, on the farm and in the home. Popular Science Monthly enough to bear the load and keep them well lubricated. Use a propeller between five and six feet long, and choose sprockets geared to turn it about 1500 r.p.m. when the engine is turning over about 1000 r.p.m. Any further increase in the speed of the engine will tend to rack it. Furthermore, greater speed of the propeller is dangerous. Mount the propeller on the shaft and test for alinement to make sure there is no side play or wabbling due to shaft looseness. This may be ad- justed by tightening or loosening the hub bolts as required, tightening all when the propeller turns true. Controls Mount a gas-tank inside of the engine dash and connect it with the carburetor. The steering-wheel and post of.the car can be used as shown. Run the post through a hole in. the dash and through another in the- timber B. Two diagonal blocks, made.” by sawing a short 2 by 3 across diagonally, and nailed to each side of the timber, give a bearing for the retaining washers as shown in Fig. 9. Run the steering-ropes (or wires) through the sides of backbone over pulleys and connect them to an up- right on the steering column (Fig. 10). This will turn the craft to the left when the wheel is turned to the left, similarly to a ship’s wheel. Fig. 11 shows the brake. This is a supplementary piece of steel riveted or welded to a brake-lever mounted on the side of the backbone near the driv- er’s seat. Connect this brake-lever by a small iron rod with the one operating the clutch of the engine. By removing the ratchet from the forward one, the action can be con- trolled by the rear one. When pulled back, it forces the brake into the ice and at the same time pulls out the clutch, running the engine free. This method is.used in starting so the pro- peller will not revolve when the engine starts. When the driver steps aboard, he releases the lever easily, and the clutch engages, turning over the pro- peller and gradually pulling the craft under way. When he wishes to stop, he pulls upon the brake-lever, dis- engaging the clutch, and brings the craft to a halt by digging the brake into the ice. Spark and throttle controls can be used as usual by extending the control rods to the wheel. Searchlights can also be used if desired with a switch at the wheel. When starting the engine, make sure that the brake is set so no acci- . dent may occur through the suddenly revolving propeller. Use the icemobile on a large expanse of ice where the most enjoyment can be had by long runs. Since it is capable, under good conditions, of attaining good speed, a small lake would not offer adequate opportunities. - Make turns slowly and use the full

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December, 1920 THE TEACHES TRADES Army Automotive School Army Motion- Picture Studio S YOUR JOB as good as you ‘want? Or does it take all your time to earn a living—with no chance to learn something better or see new places or faces? In the army a man can learn to be a mechanic, a carpenter, a 4 Y ‘ Y Ss g 7 / Gf = 4 Mi. CN on %: x a rN G ‘\ j ; \ GJ is A SOE LEE i: OEE ag painter, a scientific farmer—a skilled man in almost any occu- pation. While he’s learning, he’s earn- ing a good living—and he gets out of the old rut and into new, broad- ening surroundings, EARN, LEARN anv TRAVEL

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pi TT Sa stn Sete | | It pays to put Underwear money into “Hanes” —bigger value longer wear and greater comfort ! ELASTIC KNIT UNDERWEAR Hanes Guarantee “We guarantee Hanes Underwear absolute- ly—every thread, stitch and button. We guarantee to return your money or give you a new garment if any seam breaks.” OR years “Hanes” winter underwear for men has proven itself to be the national underwear standard; its sales exceed any elastic knit underwear! Its popularity extends from coast-to-coast! “Hanes” wins on merit! -It is not fancy underwear, but it has, enduring quality in its Hanes-spun yarn, in its “Hanes” dirécted workmanship! -And, its warmth, its service and its comfort cannot be exceeded at the price! Your confidence in every “Hanes” garment, in every “Hanes” thread and stitch can never be misplaced! “Hanes” guarantee proves that! ' $$]. JANES” underwear is made in heavy and medium weight union suits and heavy weight shirts and drawers. The medium weight union suit, new this year and illustrated in this advertisement, is of exceptional interest to every man who works indoors. It is made of full combed yarn, is silk trimmed and carries the yellow Hanes label. ‘“Hanes” Union Suits have the tailored collarette that fits closely and will not gap; closed crotch staysclosed; an extra gusset gives extra thigh comfort; buttonholes will not stretch, and last the life of the garment; pearl buttons sewed on to stay; elastic knit cuffs and ankles hold their shape; flat unbreakable seams. Shirts have the snug fitting “Hanes” elastic knit collarette, sateen vent and elastic knit wrists. Drawers are cut roomy and have the durable “Hanes” 3-button sateen waist band. ‘‘Hanes”’ for boys Put the boys into “Hanes” Union Suits—the biggest value in quality, wear, warmth and comfort for boys ever sold at the price. These boys’ suits duplicate the men’s Union Suits in important features with added fleeciness. They stand the stiffest wear and the hardest wash. - Made in sizes 20 to 34, covering ages from 2 to 16 years. Two to four year old sizes have drop seat. Inspect these remarkable “Hanes” garments at your dealer’s—at once. If he cannot supply you, write us. P. H. HANES KNITTING CO., Winston-Salem, N. C New York Office: 366 Broadway Warning to the trade: Any garment offered as “Hanes” is a substitute ' unless it bears the “Hanes” label. |New Susnanor=\ 01 VL want ko year donts Naiaseek Vnitr Suit Popular Science Monthly power of the engine on straightaways only. On extremely cold days do not use the cooling fan, as the draft from the propeller will be sufficient to cool the engine; a cover may even be nec- essary. Speed depends upon the condition, r.p.m. of the engine, and size and pitch of the propeller; but thirty-five or forty miles an hour should not be hard to obtain under even adverse condi- tions. How to Clean a Clogged Fountain-Pen SELF-FILLING ‘fountain-pen is often filled with ink that is not absolutely free from sediment. An occasional rinsing of the reservoir will aid in preventing the clogging of the Use a fine needle for cleaning the feed duct of your favorite fountain-pen feed duct to the pen, but the small duct into the barrel of the pen very often becomes clogged. In case of a clogged feed, secure a small, fine needle, and push this under the gold pen and up along the feed duct, into the ink reservoir. Then rinse out thoroughly with water and you will find that your. pen will again work properly.—G. W. GREENE. Compressing Piston-Rings to Enter a Cylinder HE illustration shows a simple and very satisfactory way of com- pressing piston-rings so that they will enter an engine cylinder easily. The piston is slipped into the cylinder as far as the first ring. Some _§sash- cord is fastened to one of the cylinder head studs, wrapped around the pis- iid idl ate ton-ring, and ria mast Aleta ing pulled up tight. Ger. Here is one way The ring is _ of doing it thereby com- pressed: evenly all around and will enter the cylinder quickly.—VAN ALLEN LYMAN. CYLINDER WALL Popular Science Monthly

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December, 1920 Moper R ADAM PERIOD 2d Seo ra08e 4 ifs Plated Reid Parts oak Let Us Send You a SILVERTONE Phonograph for Two Weeks’ Trial in Your Home Without Expense to You E WANT you to try one of these beautiful SILVERTONE Phono- raphs in your own home for two weeks without a cent of expense an ae obligating you to buy if you are not fully satisfied with the instrument. Select any SILVERTONE Phonograph shown on this , fill in the order blank and mail it to Sears, Roebuck and Co. today. We ship SILVERTONE Phonographs on two weeks’ trial. You _ absolutely no risk, nor do you o te yourself in any way by taking SILVERTONE on trial. All we ask you to do is to give the honograph test. Examine its mechanical features, ca cabinet work h. Try it with any disc record’ you desire, and note its beauty of tone and fidelity of reproduction. Give it every test necessary to prove the truth of our claims for it. d then compare the price of the SILVERTONE with that of any whe phonograph of the _— size, beauty and musical excellence, at the end of two weeks’ trial, you are not fully satisfied with the SILVERTONE, 4 you do not believe that it is in eve wey the equal of any pho: honograph on the market selling at prices f rom 25 to r cent higher than the SILVERTONE, simply notify us and we will take away the phonograph at our own expense and will refund any transportation and cartage charges you have paid. The two weeks’ test will not have cost you one cent nor placed you under any Saedien Play as You Pay—Very Easy Term: Tf, after two weeks’ trial, you are fulty satisfied with the SILVERTONE and desire to keep it, simply send us the first monthly "hie amor and then the same amount each month until the total is a he amount of the monthly payment on each instrument is shown under illustrations. Compare our terms with’ those offered on any other fs Aenea of the same high quality. The small monthly payment required on even: the highest priced models makes it easy for you to own a really fine instrument without incurring a heavy financial burden. This Liberal Selling Plan Is the Best Guarantee ‘ of SILVERTONE Quality We know that the SILVERTONE Phonograph fs right in every respect—mechanically, musically and in des: and finish. That is why we can offer them on pa ana beral no money down trial basis. We know that ‘ou get a SILVERTONE gape = in your eon or two weeks’ trial you. will be convinced of high quality and will agree with ~ that | it is the eet Phonograph on the market a ear the same price. We have sold over "005 SSILVE RTONE phonographs, and the unanim ue pra f their owners is the most convincing proof of ‘SI VERTON E quality. Plays All Disc Records The SILVERTONE convertible tone arm is so structed that it permits the playing of any make — dise record, either vertical or lateral cut. It is almost as easy to adjust the a for different types of records as it is to change needles, Size of Cabinets The Model H Cabinet is 453% inches high. The others are illustrated in proportion. MAIL YOUR ORDER TO THE NEAREST ONE OF OUR FOUR STORES. SEARS, ag gs AND.CO. 91P90 Date 1 a. me the SILVERTONE Phonograph which I have marked with an (X), You may shi without any obligation on my part to buy unless I am perfectly satisfied. ny obligation trial, I dudde 6 & keep and use the instrument, I will send yom oe few = for the phonograph and od the same amount each month until paid in full; then th RIVER TONE becomes my prope uld I decide, after two weeks’ ‘tal, that the SILVERTONE is not satisfactory, I will notify Pa... “or you are to give me instructions so that I may send ei ao = at your expense, You are also to return to me any transportation and car charges I ha have always been Yaithfu in ng my obligations and om making this statement for the purpose of inducing you to grant me these terms, and I give you my pledge that you may feel safe in trusting me to pay as agreed. 1 Sign R F. D. Box Here (Sign your name hcre plainly and —— If under age, some member of your family who is of age and responsible should sign this order with you.) Pastoffice. County. State. Shipping Poiat County. State I have been located in if less than 5 years, this town since. give former address. My business, occupation Do you wish shipment made or profession is. by express or freight? REFERENCES— (Please give names of TWO references.) ame Address Business or Occupation Woehiat oa cater Phonographs to all parts of the U.S. We donot accept orders from foreign countries. Model H. O Mahogany. “Model R, Ol Mahogany. O Walnut. O) Fumed Oak. Price, .00 Payment, $7.00 a month, “Model O) Mahogany. O Walnut. Price, i Price, $2 $7 $29 a month. oO sodden O) Walnut. C) Fumed Oak. Pri $22: Payment, ef. a month, WT ==} ot SE Roepuck belo a Cron ro} sb Cor toto me Philadelphia: Seattle:-Dallas._

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The day’s duties and the day’s doings take on a new significance following a joy-spin to work on a Columbia in the fresh air and sunshine of a dewy morning. The open road and the woods never are so inviting, so exhil- arating, on Sundays or holi- days, as when a Columbia pilots you. and put those saved sums on its purchase price. Get that 1921 Columbia now. See the various models at your dealer’s today. Write for a 1921 Columbia Catalog. Ride a bicycle—a Columbia. Live, save, be strong, healthy —do your share toward giving that greater efficiency and promoting that greater pro- duction the nation so truly needs. There is a model and a price for every individual preference—for you, for the wife, for the kiddies. Westfied Manufacturing (Co. 45 Lozier Ave., Westfield, Mass. You never realize how stiff rail- road and trolley fares are until you buy a Columbia

a

CUT YOUR OWN HAIR—EASIER THAN SHAVING PATENTED to insure a firm grip on the stem and to prevent injury to the head of the stem. Then a narrow strip of fine _emery- cloth should be wound around” the j stem, as shown in the illustration, and seesawed by alternately pulling the two ends, moving the strip up and down at the same time. Usually afew strokes will suffice to clean the stem and make it bright. The emery-cloth should not be drawn too tightly. After the stem is cleaned, the face of the valve should be wiped carefully with a cloth dipped in kerosene, to remove every trace of dirt. Then it should be lubricated and replaced in the cylinder. Mixing Acid and Water for the Battery F the storage battery requires a new solution, it should be mixed out- side and then poured in the battery tank. Chemically pure sulphuric acid has a gravity around 1.84, and to ob- tain the required gravity, 1.300, before putting it into the cells, it has to be mixed with water. Measure out two parts of the acid to five of water, and mix them thor- oughly in an earthenware or glass container, which is proof against the action of strong acid. Pour the acid into the water in a small stream (not the water into the acid) and allow the solution to cool before pouring it into the battery.

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December, 1920 Yours fora ‘‘ Merrier’’ ‘You Can Build Hundreds of Models MECCANO Toy Engineering for Boys Beam Engine ITH Meccano you can build hundreds of fascinating models in shining steel and brass—and, with your dandy Meccano Electric Motor, make Bays them run like real machinery. No study. Follow the simple directions Beet and, before you realize it, you have a wonderful Crane like the one above. ~ _ Turn the crank handle and the model will work; or run it with your electric motor. ox eC Hon) - + ~ FD i) Manual of See These Instructions with each outfit. And, Oh, whata thrill of joy it is to ¢nvent new models —to see your own ideas take form in steel and brass!. By all means, tell Dad you want Meccano for Christmas. Send for FREE XMAS BOOK Contains the inventor’s entertaining story of Meccano. Illustrated with numerous interesting pictures of models and boys building them. The kind of a book a boy likes to get wrapped upin. Just the thing to help you and Dad to pick out your Christmas outfit. Merely write us your name and address and it will be sent you in the next mail. Get yours good and early, Tower Wagon GIVEN IN PRIZES FOR BUILDING MECCANO Outfits AT YOUR DEALER’S MUTI. > av tu orn ech atembansma sic $1.50 Wille inn 2 cols daveeuheateient 3.00 And up to $40.00 Motors Electric, Reversing..... . $4.50 Electric, Non-Reversing. 3.00 Clockwork Motor....... 3.00 Transformer............ 3.25 Outfits and motors sent prepaid on receipt of price if not at your deal- er’s. X ogtfits-and motors slightly higher in Canada, MODELS MECCANO COMPANY, Inc., Division K, 71 West 23d St., New York, N. Y.

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~*~ Boston

Easy to Buy Easy to Send ‘A joy to Receive for quality, efficiency and durability

en, Women and Children The world’s standard $2.50 and up at best dealers THREE TYPES: Regular. Safety and Self-Filling... . k. Waterman Company 191 Broadway, New York — 29 South State St., sp arenciagll rancisgo

CONSTRUCTION RENT MOTORS, 4 A. E. Watson. This book contains complete instructions fo OF SMALL ALTERNATING CUR- r building small alternating current » CONSTRUCTION OF INDUCTION COILS AND TRANSFORMERS, Tells .. Full of practical note d instruction. yaand the how. Little is left to Sons work. Ope i ‘ i ri i d d core tran : # With those of the very best mamufacturers-and they eat be’ | sejuction book ‘on the whole subject this que tw hard to beat for the worked out by the amateur for making useful instruments. . siete 0 SS COM Fully illustrated. Price Postpaid, $1.25. adiciiis 111 POPULAR SCIENCE MONTHLY POPULAR SCIENCE MONTHLY 225 West 39th!Street lew York 225 West 39th Street New York

A few hours’ interesting work saves many dollars— gives you a fine machine exactly suited to your ideals—better than many machines costing much more. Plays any record. We furnish complete, simple plans and diagrams—anyone can understand them—-motors, tone arms, case material, everything required, and full instructions. F.C. Strong, Can- ada says: ‘Please send me one of your circulars, ‘How to Build Your Own Phonograph,’ as I would like to make one. Mr. Gallie has built one and if he hadn't told me that he hac made it himself I would haye taken it for a $150 model.” Listen to this from Charles F. Mancke, Wash.: ‘Received the two outfits, and am well pleased. I built one machine for myself and took an order for one for $175. I now have mine done, and it has a wonderful tone. I would not take $200 for it.” We are the originators of the home building idea. Our customers always succeed use Our pi System are easy and clear. No special skill necessary. Make Big Money Building Phonographs Ask for Our Sure-Fire Plan and Free Blae Print Offer You can meke hundreds of dollars easily, Ask us. We tell you how and he We have started many others. We can start you. Pleasant, easy work. N. J. Adams, Michigan, says: “Just sold my phonograph which I built from your plans and parts at nearly $100 profit. Only took about a week working evenings to build it. Those who have heard it Say that it is better than phonographs they have seen and heard at $200."' Become a Home Dealer—Wonderful Plan ition ys pe ready built

Get our FREE Blue Print Offer WANTED FOR OUR DEALERS Wr) bok Peck

Popular Science Monthly Leveling Liquids with an Automatic Siphon T is often very convenient to have an automatic siphon that will re- move liquids to a certain level and maintain that level although more liquids should subsequently be added. Such a siphon consists of a lead tube about 10 in. long bent as shown in the _ illustra- tion. The loop at A is at the level at which the liquid is to be kept. A small air hole is also made at the top of this loop. After the siphon has been started it will continue to function until the liquid falls to its normal level. Should the liquid rise again it will automatically drain off the surplus liquid.— ERNEST BADE.

This automatic siphon keeps liquids at acon- stant level An Experiment for the Flash-Light Photographer HIS experiment requires practi- cally no apparatus and gives im- mediate and startling results. It is simply short-circuiting the 110-volt house current with a piece of No. 36 wire. This does not blow a fuse, be- cause the current ‘blows the smallest wire in the entire circuit. A practical use for this experiment is to set off flash-light cartridges. These usually are supplied with a slow- burning fuse; but in some cases it is difficult to prevent the subjects from ‘moving while the fuse is burning noisily. A very quick way is to drop a short length of the:No. 36 wire in one of the cartridges. When all is in readiness, the photographer simply snaps on the house current, and the picture is taken.—PHILIP A. WALL. Setting Machine Screws in Thin Metal HERE are many cases where it is desirable to tap a machine screw into thin sheet metal with some assur- ance that the screw will hold, though the metal is too thin to take sufficient thread to be of a any practical use. The de- sired end is easily accom- By punching a tapping hole in sheet metal, - surface is obtained to plished. Punch the hole for the take a good thread screw with a punch that will force the metal aside, forming a sort of short cylinder, which will be long enough to take, a few threads and hold the screw reason- ably well. The best kind of a punch to use is one with a sharp point, a long bevel, and ashank the diameter of the tapping hole.

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December, 1920 The playthings of today make the men of tomorrow Ives mechanical and electrical trains, and Ives steel boats with their long running motors and screw propellers, will teach you all about the big business of transportation. You lay the tracks and install switches, signals, stations cnd tunnels. The trains are just like the real ones—with long, powerful engines or electric locomotives that whizz over the tracks and beautifully painted passenger and freight cars. Ives boats include ocean liners, tugs, yachts, destroyers, Se submarines and U.S. Merchant Marine steamships. Write for our finely illustrated book, ‘“‘Ships and Shipping,” and a big booklet on trains, full of information and finely colored plates. Both sent for 10c in stamps, to pay postage and packing. The [ves Manufacturing Corporation 191 Holland Avenue Bridgeport, Conn.

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| ; i I i i } What do you know about bicycles, anyway ! E’VE shown the Kokomo Bike Book to hundreds of ‘‘regular fellows’’—riders of many years’ standing — and nearly all of them have found some new and really valuable facts in ““The Bike Book.” They’ve been glad to learn how to pedal their bikes more easily, ways to properly clean them, and what constitutes good bicycle tires. We got the book out, first to be helpful to our rider friends, and second to remind them of the worth and good- ness of Kokomo Bicycle Tires. Until the supply runs out, we ll be glad to send a copy to anyone who asks for it. KOKOMO RUBBER COMPANY } 40 S. Main Street KOKOMO, INDIANA sy r ~. 0 wt a, “Contributors to Cycle Trades of American Advertising Campaign.” , E 4 LONG © L2/F= BICYCLE FLRZS Popular. Science Monthly Things I Made that Reduced the H.C. of L. How some readers of the Popular Science Monthly sought to solve the vexing problem T is highly significant that the over- whelming majority of the answers received from readers of the Popular Science Monthly in the prize contest “How to Beat the H. C. of L.,” launched early in the year described mechanical appliances for heating the air in rooms, shops, or houses, or for providing hot water for domestic pur- poses. So great was the numerical prepon- derance of answers aimed at the re- duction of the cost of fuel that the announcement of the decision of the contest was reserved for the December number, as most appropriate for the descriptions of the various fuel-saving devices. The first prize, consisting of $50, was awarded to E. S. Cook, of Alpena, For his method of providing hot water in the kitchen by simple means, E. S. Cook, of Alpena, Michigan, was awarded the first prize of $50 Michigan, for his meritorious method of providing a hot-water supply in his kitchen at a trifling cost. Mr. Cook first of all placed a coil of copper tubing, taken from an old water-heater, in the fire-box of his heating furnace. One end of the coil he connected with a pipe leading to a homemade water-tank placed near the kitchen ceiling; the other end, by means of another pipe, with the hot- water faucet of the kitchen sink. R. J. Hammond, of Huntington, Long Island, earned the second prize of $25 by describing how he reduced the high cost of shoes. He bought from a junk dealer an old automobile cord tire that was past mending, split it, and made from this almost indestruct- ible material soles for his shoes, old as 100 Extending the life of his shoes by pro- viding them with soles cut from an old cord tire, won for R. J. Hammond, of Huntington, Long Island, $25 well as new. These soles were cemented and tacked to the leather soles. With his description of the method employed by him for heating two rooms with hot water from the kitchen range, William Skeggs, of London, Ontario, Canada, earned the third prize of $15. He laid a 1-in. feed-pipe from the water-front of his range to an expan- sion tank holding about two gallons in the attic. From that pipe he con- ducted the hot water or steam by ‘means of T connections to two old radiators in adjoining rooms, and from the bottom of the radiators the water was led back to the range in a return pipe provided with a drain-cock. Another answer, although it was not awarded a prize, is so meritorious that it deserves honorable mention. P. C. Henry, of Conover, North Carolina, William Skeggs, of Lon- “~~ “ don, Ontario, earned the third prize of $15 with his method of heating two rooms by hot water from the kitchen range

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‘ December, 1920 describes how he built a hearth in his’ back yard from a pile of old bricks left over after the remodeling of a building. On this hearth, which did not even have a chimney, he heated the water in a sterilizing tank large enough to Using a pile of old bricks for building an open hearth for sterilizing fruit and _ vegetable preserves merited honorable mention for P. C. Henry, Conover,N.C. hold thirty cans of one-quart size. This sterilizing hearth he used with ex- cellent success for preserving fruits and vegetables grown in his garden during the season. Ten other answers selected as par- ticularly meritorious from among the numerous replies received from con- testants will be found on pages 72 and 73 of this issue, entitled ‘‘Fighting the H. C. of L. at the Cellar Furnace.”’ Here Is the Standard Scale of Tire Inflation HERE is no use worrying about the small discrepancies in the inflation pressure tables of the dif- ferent tire manufacturers. They are all near enough for all practical pur- poses. Some of the manufacturers will tell you to put 60 pounds in a 30-by-3 l«- inch tire, whereas others will vary. this to 55 or even 50 pounds in some instances. There is also a difference between the proper pressure for fabric and cord tires, the latter requiring a lower pressure than the former. Therefore the standard scale of in- flation pressures and loads as adopted by the Tire and Rim Division of the Society of Automotive Engineers is a most convenient bit of data to keep, as it gives the recommended pressure for any size of cord or fabric tires, and saves you the trouble of refer- ring to as many different charts as you have different makes of tires on your car. Here is the scale: FABRIC TIRES Corp TIRES Maxi- Corre- Maxi- Corre- mum sponding mum sponding Tire Load to Air- Load to Air- Size a Tire Pressure a Tire Pressure feet 375 45 400 40 84%.. 570 55 600 50 S- cs eee 65 850 60 4%.. 1100 75 1200 70 5.... 1500 = 85 1700 80 Trained Hands Serve Trained Minds Don’t Let Your Boy Grow Up All Thumbs! RUSSELL GREEN RIVER WORKS CARVING SETS are Ideal for the XMAS GIFT Knife of finest stee!—in 6’’, 8” and 9” sizes, and is tempered to hold the edge. beautiful stag handles, with sterling silver fer- rules. Ask your dealer for No. A-7541-E Carving Set. The three pieces have. No defect is so obvious as the untrained hand. You know a lot of men right ‘among your friends and acquaintances who lack that knack of doing things requiring the slightest manuaf skill—they are clumsy—all thumbs—and it is alla matter of early training of the fingers. ; A mn AT IilHl l ui i l | Give your boy IR SSELL BARLOW KNIFE aiid WHITTLER'S Kir It will afford him more real fun than anything else you can think of and teach him that knack of doing things which you admire so much in the “handy YOUR BOY WANTS A KNIFE Here’s your chance to give him one and direct its use along lines which will be of real benefit to him in man.’ after life. To stimulate interest in the Art of Whittling, the Joun Russert Cutiery Co. will award My $250.00 IN CASH PRIZES for the fifteen best examples of whittling done by boys with an ordinary pocket knife. silver and bronze medal awards, too. open to every boy in the land !i Ask your dealer about this Big Whittling Contest, and the Whittlers’ Club—your boy will want to join both! Price Complete $1.00 Each Kit Contains: One Russell Barlow Knife Soft Pine Whittling Sticks Whetstone Whittlers’ Manual Membership i in the Russell Whittlers’ Club Whittlers’ Club Button— to prove it to the boys. There will be gold, This contest is / Joun Russert OutteRy (p. Green River Works TURNERS FALLS, MASS., U. S. A. wn al and a So Roe ee CLM A i a Sa a aS aa

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IVER JOHNSON AUTOMATIC REVOLVER SAFETY

«See, it can’t go off aucidentally” “The only way to discharge an Iver Johnson is to pull the trigger (1) all the way back. This action raises the lifter (2) which forces the hammer (3) to cocking position. When lifter is at its highest point, the hammer covers the firing pin (4) and at this position the hammer is released, striking the lifter, which in turn strikes the firing pin.” No impact can force the hammer against the firing pin. Thus the world-famous slogan ‘‘Ham- mer the Hammer.”” And that is why women are not timid about having an Iver Johnson in the home. Drawn tempered piano-wire springs keep the Iver Johnson permanently alive and alert. And the perfect rifled barrel speeds the bullet straight as a streak of light. Choice of three grips: Regular, Perfect Rub- ber, Western Walnut. IVER JOHNSON’S ARMS & CYCLE WORKS 343 River St., Fitchburg, Mass. $9 Chambers St., N.Y. 717 Market St., San Francisco

If your dealer hasn’t in stock the Particular model you want, send us his name and address. We will supply you through him. Three Booklets—One or All Free on Request “A’’—Firearms; “‘B’’—Bicycles; *“C’’—Motorcycles

Iver Johnson Bi- cycles are world- famed for easy : idi. trength, Iver Johnson Single and riding, s A Double Barrel Shotguns yt nee os eardens combine accuracy and to suit everyone dependability. ud y sf

YOU Can Do YOUR Own | | Learn How toWrite] SOLDERING and All Short Stories ther is: 1 eman M etal eoamenggiee for short stories, photoplays and w ~* articles. es eo how = ith and o no be rea ese sabaanl our cong course. The wl % gn inating and takes only-a few your spare hours. 5 ; d details of our Limited 1 —j 4 $ Write for Free Book pete ofier. N a ainiaine. < ‘a me HOOSIER INSTITUTE, S.S.Dept. 1789 Ft. Wayne, Indiana a Spe s z | 4 2 i“ } ¥4 n A PASTE \ % 2 % = THAT TURNS 88.3 = es 815 to $25 on the model INTO METAL tr Zz Rn”, - WHEN HEATED [eae a ress ‘Tomier tine eat, Delivered A match will doit. Requires no , ee 9 Haercic te: ie S | Seen wes hanew dee one 3 “uestyere Me | Wired ore ee SOLDERALL CO., Dept. A, wes oan ware to i esthiy parm — 129 SUSSEX AVE., NEWARK, N. J. res ete navel eric TQOMBINATION SET ¢4 50 aeBtS a sider ects with mar Dealers Send for Quantity Prices rn Look for Trade Mark “SOLDERALL."" | Beware | Mead:

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Popular Science Monthly To Make Cardboard Models of Engines OST designers of machinery find that to lay out the movement of the device is to invite a good deal of work with a considerable loss of time. This is true of all classes of designing, whether the device is just ordinarily complex or very intricate, or whether it is a monster engine to be used on an ocean’ greyhound, or merely a small model of such an engine. In order to determine the action of the engine through all the cycles of its com- plicated movements, a drawing must be made of each and every phase. Even though a finished drawing is not required, these drawings must be laid out in the same plane. After a number

Cardboard models like this clearly illustrate the movements of the ngue pistons of layouts have been made, one on top of the other, the result is one of confusion rather than of simplicity and the.complete cycle of action is difficult to follow. To make a finished model takes time and costs too much, especially when the design that is being worked out is a new idea and may or may not be practical. In that event it surely would not be desirable to go to the expense of having a finished model constructed. So why not make a

This shows the pistons of the V-type engine pictured above in a different position model of paper? It will answer the purpose and will tell the story quicker than any other way. A model made of cardboard is shown in the accompanying illustrations. The model in this instance is that of a V-type automobile engine. - No attempt is made at showing contour, the idea in mind being merely to illustrate the movements of the dif- ferent parts. In making this model,

© tS oe “4 mh —s A — =o J TH oa un- sek Be 6G oe 6

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December, 1920 thin but stiff bristol board was used. A piece of heavy cardboard served as a foundation on which to build the rest of the model. The cylinders were made by cutting some of the cardboard away at an angle and bending up slightly. The sketch (Fig. 1) illustrates this. The cylinders can also be made by pasting two thicknesses of. cardboard together, leaving about 1/16-in. overlap as shown in Fig. 2. The pistons, which were of a single thickness of cardboard, could easily slide back and forth between the cylindet walls. The bearings for the connecting-rods were made as shown in Fig. 3. The piece A, which really is a true bearing, was slightly thicker than the connecting-rod, which per- mitted sufficient play for the rod. The crankshaft was made of two disks, one connecting-rod being fitted to the top disk and the second con- necting-rod being fitted between the CUT AND TURN UP Dh = _PISTON CYLINDER FIG. CYLINDER mse OZ FIG2 PISTON SS FIG.4 GUARD-RING - The diagrams shown here illustrate in detail the exact manner in which the various parts of the engine model are cut out of bristol board and put together two disks as shown in Fig. 4. The crankshaft assembled was fastened by the same method as the connecting- rods. A circular ring guard piece was pasted to the back of the foundation so that when the crankshaft was turned there was no binding of parts. To operate, a stylo was inserted in a hole in the top connecting-rod and the crankshaft was then revolved. Every degree of revolution of the crankshaft could then be studied along with the action of the various other parts.—FRANK HARTH. Watch Your Storage Battery in Cold Weather OTORISTS who use their cars all winter should be careful to see that their batteries are kept properly charged. A battery that is allowed to deteriorate or become even partially discharged is far more likely to freeze than one that is kept in good condition, as may be readily realized by comparing the following freezing- |. points: Specific Battery Freezing- Gravity Condition Point 1.280 = Full 70° below zero 1.260 14 discharged 60° below zero 1.210 1% discharged 20° below zero 1.160 34 discharged zero 1.120 . Empty 20° above zero am your razor- Joy in Shaving — lies in Perfect Confidence an yourself, And that is all there is to the simple, pleasant, gentle- manly art of shaving. Thirteen years of practical demonstration in the hands of more than two million confident users, furnishes that full confidence I have felt necessary for the right advertising of the onders Vlagor Simplicity is its charm—cutting the beard quickly and easily, without scraping the skin, is its peculiar merit. Ease of adjustment, perfect cleanliness, iightness, firm- ness, beauty—and the $1.00 it costs—are contributing elements to your joy in shaving. Shaving with an Enders Safety Razor is ‘Just like wiping your face with a towel.’’ Enpers SALes CoMPANY, 17 Battery Place, New York ENDERS SELLS FOR $1.00 with six blades of the best quality Swedish-base steel. Packed in a black Keratol box, velvet-l'ned. Extra blades—package of 5—35e. FOR SALE BY BEST DEALERS-EVERY WHERE

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’ Bisjclogh Neng Does Dad Remember? If dad will just think back to his boyhood days—if he'll just remember how much he wanted a bicycle—and how much fun he had when he actually got one—he won't let you be disappointed again this Christmas. ' Good, healthy fun—quick, convenient, econom- ical trips to school or work—wholesome, boyish | companionships—'no boy wants to be “the boy without a bike.”

q Write today for your dealer’s name and copy of we book she handsome new 1921 Dayton catalog No. 44 showing 8 witheur models for men, women, boys and girls. reputation Dayton Bicycles

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* THERE'S MONEY INIT” =A=LEARN TELEGRAPH Y= yore ___-_MORSE AND WIRELESS—-—-— ee SP Ga © 6 CRED: oe On GEES. @ ow eee eee ees oe we eee et Oe in half usual cost, with the wonderful TEACH YOURSELF automatic Transmitter “THe. OMNIGRAPH. Sends orse Continen' messages, speed, expert anv gy evo ae ‘by U. S. Gov't. and leading: Universities, "Colleges and Teie- graph Schools. 4 styles. Catalog free. OMNIGRAPH MFG. CO., Dept. H., 26 Cortlandt St., New York. 104

Popular Science Monthly Secret Marks Aid the Identification of Cars T is believed that at least one auto- mobile out of every dozen manu- factured and sold is stolen. How many stolen machines are ever re- covered by their rightful owners, is another question. Good locking devices, or thief sig- nals, are not to be despised. They are a sure protection against depredations by meddlesome men and boys, and will cause the automobile thief so much trouble that he will look for a car that is easier to take away. Where several cars are parked, this will not be hard to find. Comparatively few cars are left well locked, and many stand without being locked at all. Owners sometimes forget to take the switch- key with them, leaving it in the switch-lock. Should a professional automobile thief get your car, he will take good care that you will not recognize it should you see it again. You know it now chiefly by its license plates, car and engine numbers, and a few scratches, dents, and slight peculiari- ties. He discards the license plates, changes the engine and car numbers, and obliterates every mark by which you might identify your car. Caution is his middle name. He likes to tear down several cars of the same make, and reassemble them so that no two of their principal parts will be found in any one car together. He has looked everything over with great care, to see whether your initials are hid- den under a washer, or whether there are prick-punch holes anywhere con- cealed. Lest you identify some scratch or dent, he may use new fen- ders and repaint the car. If you could make a decisive identi- fication of a body, frame, engine, gear-case, rear axle-housing or front - axle, you would stand the best kind of a chance to take that car away from a crowd of claimants, even if your markings could be found on but one of these parts. How near can we come to a system of invisible markings, unlikely of chance duplication, and readily dis- coverable by the owner or some one authorized by him? ‘There is safety in numbers. Several markings on each part make it less likely that all can be obliterated. Take, for an example, the following memorandum of a secret mark: “734 in. horizontally to the left of center of the right engine suspension bolt, scrape off the paint and find a drilled hole filled with lead.” If you have several such marks, carefully recorded, on different parts of the frame, your identification will become more positive, as it is. highly improbable that two or more of these marks would be accidentally duplicated by some other person. Many other methods of marking

the car will suggest themselves to the

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December, 1920 inventive owner. It must be re- membered, however, that secret iden- tification marks are worthless unless they are carefully and exactly recorded and a record of them pre- served.—HENRY R. THAYER. Using a Dial Indicator as a Sweep Tester HE common practice of attacking a pointed sweep to the spindle of a drill-press or lathe to test the trueness of the table or faceplate has the disad- vantage that it is rather difficult to see by eye whether the point is actually touching; in fact,-it may be just clear- ing or pressing with considerable force. Chalking may relieve this, -but it sometimes is difficult to chalk a smoothly surfaced table. The better way is to mount a dial test-indicator upon the sweep, for then “the exact measure that the table is out may be directly read. The illustration shows an adjustable; sweep made up for a heavy drill-press. LATFIE FACE-PLATE SWING MADE . TEST OF BENT-UP So: os | DRILL-PRESS PLATE TEST By using a dial indicator on the lathe the trueness of the faceplate may be exactly ascertained The vertical piece is tapered to fit into the spindle sleeve and is drilled through at right angles near the bottom for the horizontal rod which carries the dial.: A set screw holds the rod in place. For a small light drill-press provided with a nut, a piece of steel rod may be bent up to suit, the vertical end being held in the chuck. In testing lathe faceplates, an adapter may be made to fit the tailstock quill, drilled at right angles for a rod like the first one anda set screw put in to clamp the rod. The adapter should make an accu- rate, scraped fit into the tailstock taper, driven in rather tightly, and then the tailstock serew slackened off. just enough to loosen the adapter so that it will turn rather stiffly. The indicator may be set at any distance out on the rod.—H. H. PARKER. Home Soldering Made Easy with a Good Flux OES your wash-boiler leak? Close the leak with solder. Small sol- dering sets are sold for a trifle and are very useful in the house. A solution of sal ammoniac and borax makes a good soldering fluid, particularly for copper and brass. For tin the resin- ous flux supplied with the soldering- set may be used. ‘Scrape the surfaces ‘cous film. _It clings to teeth, enters crevices and well before soldefting.:° * © Never Sleep ‘With a film-coat on your teeth Millions of people on retiring now combat the film on teeth. They fight it day by day. And those glistening -teeth seen everywhere now form one of the results. You owe yourself a trial of this new teeth-cleaning method. Dentists everywhere advise it. The results it brings are all-important, and they do not come without it. What film does Your teeth are coated with a vis- Feel it with your tongue. stays. And dentists now trace most * tooth troubles fort. . The ordinary tooth paste ens not end film. So, despite all brushing, much film remains, to cause. stain, tartar, germ troubles and decay. Watch the You will see and feel results from Pepsodent which brushing ~ never brought you heretofore. A week’s use, we think, will amaze you. One ingredient is pepsin.. One mul- tiplies the starch digestant in the sa- liva, to digest all starch deposits that cling. One multiplies the alkalinity of the saliva to neutralize mouth acids. Two factors directly attack the. film. One of them keeps the teeth so Papsadé ant REG.U.S The New-Day Dentifrice A scientific film combatant com- bined with two other modern req- Now advised by leading dentists everywhere and supplied i uisites. by all druggists in large tubes. 105 It is the film-coat that discolors, not the teeth. Film is the basis of tartar. It holds food substance which ferments and forms acid. It holds the acid -in contact with the teeth to cause decay. Millions of germs breed in it. They, with tartar, are the chief cause of pyorrhea. Ways to combat it Dental science, after years of re- search, has found effective ways to fight film. Able authorities have proved their efficiency. Together they bring, in modern opinion, a new era in teeth cleaning. These five methods are combined in a dentifrice called Pepsodent—a tooth paste which complies with all the new » requirements. And a ten-day tube is now sent free to everyone who asks. teeth whiten highly polished that film cannot easily cling. Watch these effects: Send the cou- pon for a 10-Day Tube. Note how clean the teeth feel after using. Mark the absence of the viscous film. Note how teeth whiten as the film-coat dis- appears. The book we send explains all these results. Judge what they mean to you and yours. Cut out the coupon so you won't forget. 10-Day Tube Free“ THE PEPSODENT COMPANY, Dept. 21, 1104 S. Wabash Ave., Chicago, Ill. Mail 10-Day Tube of Pepsodent to | ee Only one tube toefamilyy »

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Training For Service What science and engineer- ing have done to develop the mechanical efficiency of the telephone, specialized training has done in the development of workers. Plant engineers, linemen, directory clerks, toll. operators, equipment installers, electrol- ysis engineers, trouble hunt- ers, line repairmen, test table operators, chief operators, con- tractagents, building engineers, line installers, exchange repair- men, plant inspectors, trouble operators, fundamental plan engineers, draftsmen, estimate clerks, exchange operators, cable testmen, equipment in- One Policy spectors, wire chiefs, traffic engineers, galvanometer men, cable splicers, facilities engi- neers, surveyors, information operators, switchboard install- ' ers, accountants, testmen, su- pervisors, station repairmen, equipment engineers, directory operators, statisticians, ap- praisal engineers, routing op- erators and scores of other skilled employees are specially trained for the exacting work of providing telephone service. Throughout all work of tele- phone construction and opera- tion there is a ceaseless en- deavor at mastery of service that makes for improvements beneficial to the public. AMERICAN TELEPHONE AND TELEGRAPH COMPANY AND ASSOCIATED COMPANIES i One System Universal Service And all directed toward Better Service Electrician’s Wiring Manual By F. E. SENGSTOCK, E. E. contains all the information needed for the proper installation of light- ing and. power systems in houses and other buildings. This manual is writ- ten in simple, plain English by an lectrical Engineer with many years’ experience on the Chicago Board of Underwriters. Profusely illustrated and contains many tables and for- mulas. Pocket size, flexible binding, 448 pages. Price, $3.00 postpaid. POPULAR SCIENCE MONTHLY -- 225 West-39th Street New York City : °225 West 39th Street Experiments with 110-Volt Alternating Current By J. D. ADAMS Here at last is a book that develops a prac- tical working familiarity with the alternating. current—the form in which electricity is use in every home. The author shows ee this can be done in an interesting and inexpensive way. ‘ The only way to gain a thorough understand- ing of electricity as it is used commercially is by direct personal experiment. The knowledge thus gain is of vastly more value and im- portance than that acquired from the. perform- ance of the stereotyped series of battery exper- iments so uniformly described in the text-books. 256 Pages, 135 Illustrations Price, Postpaid, $1.75 Popular Science Monthly ~ New ‘York 106 Popular Science Monthly A Combined Burglar Alarm and Keyhole Lighter F you are at home and any one at- tempts to turn the knob of your front or backdoor, a bell will ring. If you come home late in the evening, turn the knob yourself and a flash- light appears from the interior, dis- playing brightly the location of the keyhole. Such is the operation of a small outfit which will cost the maker not much more than one dollar and take but an hour’s time to construct. You may. be able to purchase the following four things at a local five- and-ten-cent store: (1) A two- or three-point battery switch mounted on a wooden base; (2) A small flash- light battery; (3) a small flashlight bulb for same, and (4) a small electric buzzer or bell. If you succeed in this, the balance of the cash will purchase sufficient wire to make the connec- tions. On the inside of the door, take off the little plate or disk through which the doorknob handle ‘protrudes. To do this it is necessary to take out the little screw which holds the knob in place, removing the knob and then the plate. From a piece of heavy tin, cut from an old tin can, make a pointer arm (see Fig. 1) having a square hole in the center, as the rod which holds the knob is usually square. This tin may be materially strengthened by soldering one or two (one on each When you return to your home late at night, you will find the illuminated keyhole very welcome side) Chinese copper pennies to the base. In this case it may be necessary to do some slight filing on the interior of the square hole so that it will fit the square rod. Placing the pointer on the rod, the latch remaining in normal position, place two round-head upholstery tacks on each side of the extremity of the pointer in the door, so that if the handle is turned the least bit -either

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December, 1920 way, the end of the pointer will come in contact with the head of a tack. These four tacks should be connected by a fine copper wire before being driven in completely, the wire ex- tending through a small drill-hole to the edge of the door (see Fig. 2). The plate, if hallow, can now be replaced over this contacting device. If it is made of wood, it is an easy matter to cut a Kole of sufficient size to allow | free movement of the pointer. If the plate is solid metal and flat, take out the entire handle rod while counter- boring a hole with an extension bit, CHINESE PENNY UPHOLSTERY TACKS WIRE te | These diagrams and sketches show the detail of the combined burglar alarm and keyhole illuminator large enough to sink the pointer and tack-heads so they will not come in contact with the plate when once replaced. About 1 in. should be sufficient. Ten or twelve inches above the handle of the door, cut in from the edge a space large enough to ac- commodate the flashlight battery. In my case the battery was 24 im. long, 1% in, wide, and 5% in. thick, and I allowed 1/16 in. for variation of the thickness and }% in. for variation of the length and depth.. Two pieces of heavy tin whose width is about 4 in. shorter than the thickness of the battery and whose length is the same as the depth of the hole cut for the battery, of copper wire before tacking the strips in their respective positions shown by Fig. 3. A couple of tacks through the smallest end hold the strips in spring tension and the battery is slipped into position between, making contact at top and bottom. A round-head screw from the inside of the door holds the battery from jarring out. Just below this battery pocket, but on the inside of the door, mount the are bent at right angles | about 3% in. from one end. On the , underneath side of the smallest end | of each piece solder one end of a piece | | Reksb gn Automobile TractorandFlying HENRY J. RAHE Founder and President HAVE saved 34 years o: e over 2 million dollars in building up m Z , until now it the greatest and most roficient Automotive Fraining Schoolin ex- mce, Floor Showing the greater size and importance of the Rahe School with its floor space idealized into 20-story skyscraper building. Ra Business OME to the Rahe School—the world’s old- est and greatest Automotive School—and get into a steady, big paying business. Make your- self sure of a steady, big income. -The 9 million Automobiles, Trucks and Tractors now. in use have got to be kept up and running. Thousands more of Rahe Trained men are needed for that right now in every section of the country. Prepare yourself here in 6 to 8 weeks, and take your pick out of thousands of high-pay positions now waiting for you. Or open nara own business in any one of the 50,000 places now callmg for new shops and sales agencies. As a Rahe Trained man, you always-have the advantage over all other men not trained here. 38,000 men already Rahe Trained are better trained men. They know the best and quickest way .to learn the business is school. I always have more calls for men than I have students, 1e School 2 Million Dollars Invested AUTO—TRACTOR— AIRPLANE 14th Year—38,000 Graduates \ tu ), he thousands of Rahe Trained men now in business aS Nut for themselves in every State are always sending WS yt. to me for more Rahe Trairied men than I can Sif, furnish. By coming here, you get preferred , or for a good job, or for a busi- ness of your own immediately upon leaving the school. Four (4) big buildings (equal to 20-story skyscra 0; big tractor farm and big flying field. mplete and thoroug training in every branch of the business. Plenty of oppecsanys to earn partlivin expenses while in school. Hundreds o men are doing this every day. Low-Priced Life Scholarship Now. ree talog Before you arrange to 4 Fi Ca go to any school, visit ~.) this School. If you can’t come | ' now, do the next best thing —sen@for my 84-page free catalog. The coupon below willdo, Catalog shows ful- ly by photographs how you learn best here—how you are sure of the best ‘ opportunities after your Rahe Training. HENRY J. RAHE Mail This Coupon ': *pccial tuition illustrated catalog giving proof of graduates’ success and ubowe fi ing the many opportunities now open. All sent FREE.

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enaeee Raps ee nag - marten trance in ate prapernery oo merrencnnesees Fume ee 9 “Wey mee Mechanical Engineering

Learn at Home! Employers everywhere are locking for men with mechani- cal ability. Splendid salariesand rapid advancement are offered. There is an easy, delightful way in which you can learn right at homein spare time. For 30 years the International Cor- respondence Schools have been giving men and women just the training they need for success in mechanical engineering and more than 200 other subjects. Hundreds of thousands have. stepped into good positions through I. C.S. help, but never were opportunities so great as now. Let the I. C. S. help you. Choose the work you like best in the coupon below, then mark and mail it today. This doesn’t obligate you in the least and it will bring you information that will start you on a successful career. This is your chance. Don’t let it slip by. Mark and mail this coupon now. ——_“. gy before you. You are taught every good blow used in the ring, when to use it, moa to land it, and how to guard against your opponent’s ows To develop your speed, you practice three rounds of shadow boxing daily, using such scientific blows as the Mike Donovan Double, the Jack Dempsey Triple, the Bennie Leonard Triple, the Fitzsimmons Shift, etc. Then comes instruction in Jiu Jitsu—how to disarm an opponent with pistol, dagger or club, how to stop a kick, how to break a strangle hold on your throat,-’etc. The Wrestling Lessons eo the tch Toe Hold, the Stretcher Scissor Hold, e The Health hoon: ob od designed to build strength and endurance—not simply muscle—and include the Colon Exercise, a remedy for constipation, and Synthetic Breath- ing, a great lung developer and aid in curing nervousness. Other features are a history of 69 great prize fighters, with their cng (tells inside stories not generally known, their pet blows, etc), lessons in Mass Boxing, an article on training, and a copy of the new International Sporting Club’s Boxing Rules. here are 246 illustrations—some course, eh? Sent Free on Approval We send the.entire course (6 books) on approval. Order eow, and pay for it on the 15th of next month ($5 in the , $6 in Canada, $7 in foreign countries). If you don’t like. the course, return it in 10 days, and that will end the matter. But you'll keepit allright! Mail the coupon now. Marshall Stillman Assn., Suite F-112, 461 Fourth Ave., New York eseeseewaunwawe: COUPONee ew ee masa = Marshall Stillman Association Suite F-112, 461 Fourth Ave., New York You may send me your complete course in Boxing and Self Defense, including extra inateaction described above. I give you my pledge that you may feel safe in trusting me as agreed, and that | wil $8 ($6 Canada; $7in foreign countries) for the course on the 15th of ant month or return it in 10 days after I receive it.

f you can keep your spine straight and strong. Then avo can nffintain in perfect health and vigor the vitality and energy of man body. ou can side-stcp old age, stiff joints and nerve trouble Mf yo you will. FREE BOOK. THE TEN-SION COUCH CO., 505 Superior Building, CLEVELAND, OHIO.

IT MAY SEEM IMPOSSIBLE BUT HERE IT IS POPULAR MUSIC _ written and arranged in ragtime form with all that wonderful left hand bass that you love to hear and above all would love to play. After years of concentration on this particular style of PIANO PLAY - ING, this is our first offerin: Hundreds of letters are pouring in every day asking us for pumbers. All trieks of ragtime piano playing will be found in our publica These copies are easy to read and easy to play. Upon reer eet of 30 cents we will ae mail you a copy of this number entitled, “‘THE DAY THAT YOUR PROMISE COMES TRUE’’ Send for this oo fox trot and when you play it for your friends they’li think ragtime was just born in you PHIL LOMBARDI’S RAGTIME MUSIC co. 1321 Flatbush Avenue, Brooklyn, New York. SIMPLE WIRELESS TELEPHONES AND HOW.TO MAKE THEM. An elemental book on the ape oe construc- yon and use of - are stem of wireless y. Price, 5 cents pos —_ ok Department, POUL ar Science Monthly, 225 West 39th Street, New York City _t

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December, 1920

’ Have a Business of Your Own In addition to the handsome salaries and quick advancement offered by employers everywhere in the auto industry, there is a wide-open opportunity to start a business of your own. Ten Million or more automobiles, trucks and tractors throughout the United States and Canada have created a tremendous demand for garages, repair shops and service stations. Thousands of openings in good territory are awaiting you: Very little capital is required when you know your business. Many of our graduates take good positions and save a few hundred dollars, then start business for themselves, while many others go right from our school into business. You can dothe same regardless of your age, education or your. past experience—if you have the ambition to go ahead. Make $500 a Month and More Hundreds of our graduates (many of whom knew nothing of automobiles or tractors before training) are now making $5,000 to §10, 000 a year. Many of these merrhad-little or no capital. Here are a few examples from our thousands of successful graduates: with more business than he + handle with three men. Se} Before training at M.S. A. S.,H. A. Bradley of Cleveland, was a shippi J. S. Steckel of ee Ill., was a loom fixer at $18.00a week. He Seanad at the M.S. A. S. and now he has a garage of his own paying a profit of over $100 a week. Tony Oandres. Austin. Pa., was a common laborer. Now he has a garage W. F. Harms of Eldridge. Iowa, was a farm hand at $35.00 a month. Today. after — at M.S. A. S. he has a garage business and three helpers; profits are $506 a mont! Before training. Byron Hulton at Floyd, Va., was working for $40 a month. Now he has a half interest in a garage business that pays a profit of over $1,000 a month. clerk at $12.50a week. Now ‘he has a business of his own in Cleveland, monthly profits over $500 a month. C.F.S Soe Chy. Ia., was working by the day. Now his profits run $520 a month i gm a Marten Vander Bie and F. <=. Dulyes of Holland, Mich., M.S. A. S. graduates, have one of the best garages in Western Michigan. All Leading Manufacturers Endorse Our School latestfequipment for our students’ instruction. The thoroughness of our methods, the completeness of our equipment and the competency of our gradu- ates are well known in the Auto Industry. Such factories as Packard, Maxwell, Hudson, Chalmers, Hupmobile, King, Buick, Oldsmobile, Paige, Federal, International Harvester Co., Emerson-Branting- ham, Moline and many others endorse our Courses, employ our graduates and furnish us with their In fact, many of the leading manufacturers assisted in outlining our courses. S, What We Teach HUDSON MOTORYCAR COMPANY y DETROIT. MICH.US.A. Automobiles and Tractors. Wyuii¢Gni castor The Michigan State Auto School in our opin- 1 business from A to Z. Very thorough and complete training is given institution of its kind in the ion, is the | ng Bg nye EA its method of | in electrics, starting, lighting, ignition, wiring, testing, repairing, in- cluding batteries, etc. Our equipment and: instruction are positively the best obtainable. _ We give actual factory experience in assembling, block testing, bearing scraping, valve grinding, road testing, etc. Complete and F T; I i arm fractor Instruction. (oroch instruc tion in the principles, construction ani operation of automotive equip- ment used onthefarm. Lighting plants. stationary engines, tractors, their care and repair are part oi the M.S. A:S. Rezular Course. Tractor Course includes actual work on M.S.A.S. Eighteen Acre Farm, “ ey Complete training for operating a Tire Repairing. tire repair shop or for production work ina tire factory. Course includes retreading, vulcaniz- \, ing, all types of cord tires, etc.

Anyone can learn by our factory —- factory endorsed methods. M.S. A. training covers every point of ree rh and practice required of a successful auto- motive expert. We have recommended a great many stu- dents to them and the results were satisfactory. The Michigan State Auto School ranks high- est in the standard of schools. Its equipment and personnel is second to none. This school is considered one of the most efficient schools in the country. If you intend to visit any school, then by all means choose the best one. The Michigan State Auto School, so far as we know is the best. You will make no mistake by entering for a course. Yours faithfully, HUDSON MOTOR CAR COMPANY, Service Department

Dertror. Nice. US.A.. The Michigan State Auto School enjoys a very enviable en tation and is men one of the best of its kind in the United States. Have no hesitation in recommnndies it in every par- ain, Yours very tru’ wih CKARD MOTOR CAR COMPANY. CC SEND THIS COUPON TODAY MICHIGAN STATE AUTO SCHOOL 2 Bldg., 687-89-91 Woodward Ave., Michigan, U. S. A.

®

Oxy-Acetylene Brazing, Welding and Cutting Complete training in structural and repair work. duct a business of your own successfully. Big 124 page Catalog. i REE shows actual pictures of on | school Sy rn | hes y= ul vdye tg eg? insive tet to learn | the business in Detroit a | the Auto Industry. Use the coupon now. a 5 G u West Progressive Auto Schoolin America”— ‘tn the Heart of the Auto Industry” The M. S. A. S. can teach you how to con- Tells complete story— para ed letters from factories and grad points out the MICHIGAN STATE AUTO SCHOOL eee Detroit,Mich,U.S.A +"

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Te nae ae a ae ee et $100 00 A WEEK’ Making. fe) fe) , Tires ME CHAS. EVANS, aca Cars penter, past fifty, laid aside saw and hammer, learned Tire Sur, ay within two weeks, nowhas thriving Surgery Station shown above. Averages 7100 a week. Alwayshasmoneyin ket. Never pinched for ready cash. n’t have to wait for ay days. Money flows in ose hour of day. It’s a proposition can handle, me equip a E Station for YOU. Learn Tire Surgery—the n tire repairing method. The QUICK ee BETTER way for repairing old, worn, ragged and torn casings. Adds $,000 to ,000 mileage. I teach you in fourteen short days. Show you how to be SUC- CESSFUL MANAGER. ell zo uu to build BIG TRADE quickly. Giveyou pointers that make you SUCCES SFUL rom VERY START. I put you into auto a gh mel ee that makes millionaires. DIRECT LINE for SPEEDY" RAISE i in HIGHLY PROFITABLE FIELD. Nothing can stop you. Need noexperience. Nospecial qualifications. .No high education. Age makes no difference. $3,000 to $5,000 Year oaverage | earnings. Many make more. Chan sensational success never Seven million cars ae oor the country, Twenty-eight million ti constant use. All are aan down, being cut, omnont, bruised EF and gashed ! ce a Cones of thousands roll- ing in ; YOUR SHARE: of this ENORMc D ‘to . T iG SCHANCE ! Amoney-makin you cannot afford > overlook! Full cost you red | Get Facts’ Fillont Coupon m3 Write name and address plainly. Mail i it qiek a4 sant = big, interesting book Read —_ others have Be Read ae YOU GAN Find out how to be own boss. whe oe YD Lo not for hours you work. Ow easy you can get into big paying, permanent business, ab ll out coupon—and SEND TNOW! “ ocd Tire & Equipment 794 Capitol Aves lodianepolig MR. M. HAYWOOD, Pres. P Havwood Tire & Equipment Co., . 794 Capitol Ave., indianapolis, Ind. Dear Sir—I_ want to get into big paying business quick. Please send me your propo» gition at once. Yours truly, Wood will bein demand this winter. You can eee big money with the Phillips One-Man Drag Saws 15 to 35 Cords Dail Fells trees — makes ties. Engine also runs other _ farm machinery. a ran my Phillips Saw one day and made $386.80 sawing stove wood lengths. All done with one anya te gw ak A. Coverdale.”’ Just send name—a ecard willdo—for free folder and money saving prices. PHILLIPS DRAG SAW MFG. CO. 765 Phillips se Menens City, Mo, | © cash art as- signments, MAGAZINE lessons and articles on Cartooning, Designing, Illus- trating, Lettering and Chaik-Talking. Criticises amateurs’ work, Full of in- formation for artists and art students. Satisfactory or money refunded. 20c a copy, $1 a year. Send $1 NOW, Thrift Stamps Taken G.H. LOCKWOOD, Editor, Dept. 613, Kalamazoo, Mich. ) Publishes How to Construct a Small Farm Tractor SMALL tractor that can be built in the farm shop is shown in the _illustrations. It can be constructed mostly of parts of old farm machinery and other scrap material. It is driven by a 12-hp. motorcycle engine. It can do all the work that could be done by one horse, such as plowing with one plow, harrowing, cultivating, and pulling fairly heavy loads. Being equipped with a belt pulley, it can also be used to pump water, saw wood, run dairy machinery, charge the batteries of a lighting system, run an ensilage cutter, corn-huller, or any other belt- driven machinery. The frame of the machine is of 24% by 4 in. ash, put together with 14 in. bolts. The corners are strengthened with angle-irons made of 3 by 1% in. iron. All dimensions are given in the plan view. The bull wheel is made of two old mowing-machine wheels bolted together with 14-in. lengths of 2 by 4% in. L-shaped angle-iron. The wheels are mounted on a 114-in. shaft, which is provided with aioe bearings. The bearing mounting is shown in Fig. 5. The bearings are made as dust-tight as A motorcycle engine and some parts of old machinery will help make a prac- tical tractor for use about the farm possible by a heavy leather washer at each end, held in place by a steel washer which is turned with a shoulder so that it can be fastened to the shaft. The driving-gears have a 1-in. face. They are mounted on 11/-in. shafting with babbitt-lined _pillow- blocks for bearings. These are made dust-tight in the same manner as the roller bearings. The ratio between the gear on the bull wheel and the driving-gear is four to one. The two outside gears should be 12 in. in diameter. The small gear on the belt-pulley shaft is 3 in. in diameter. The clutch on this shaft can be con- structed as shown in Fig. 1, but if this type is used, it will be necessary to have an engine which is equipped with a clutch so it can pick up the load gradually. If an old automobile clutch can be obtained and mounted on the belt-pulley shaft a plain sprocket can be used on the engine. The shaft should turn at one half the engine speed. The method of fasten- ys. ee 1 , “ a 2 — es 110 Popular Science Monthly ; poh ¥ i) Homé Trainat 4 Yjjjwre YF ybtddbid Let Your BUSINESS TRAINING Be of University Grade The urgent need of business today is for high-salaried executives, managers and de —- mental specialists. Under the alle lem —— you can get, in your spare time at home by mail, under expert guidance, training which parallels qotusl boon practice. The Univer- sity’s staff of 1750 people includes 450 business authorities, sacamien and assistants ready at all times to give prompt counsel and advice to enrolled members on any business question or problem. This is a service not obtainable from any other educational institution. Write your name and address at the bottom and mail today. We will send ull = mS le ined men; also our interestin, k, a Years’ Pro- Sug w cost and convenient onthly terms whishanvenoaeneneed. Mone refunded if dissatis fied upon completion o: course. More than 225,000 have enro oa Find out what LaSalle training can do for you. Check an and mail the coupon | NOW. TLaSALLE EXTENSION | UNIVERSITY Dept.i283-R FP ser sero a. Gentlemen: Send without obligation to me infor- mation regarding co’ course. indicate eel also 0 copy of yourinteresting Ten Years’ Promotionin One.’’ OHigher Agrounting OBanking and - mecoal DCoaching for C. P. A. & ORemaes Letter OBusiness Management soa aw OTraffic Management — (Commercial Spanish Foreign and Domestic F Expert Bookkeeping OLaw—Degree of LL. B. O Effective Speaking OCommercial Law OBusiness English OPersonnel and Employment Management Present Positi Name..... eececece evcccece Address.........0...coccccccccccccscces eeococececceeeese TWENTIETH CENTURY Book of Recipes, Formulas and Processes This book of 800 pages is the most complete Book of Recipes ever published, giving thousands of recipes for the manu- facture of valuable articles for every-day use. Hints, Helps, Practical Ideas and Secret Processes covering every branch of the useful arts are given. 10,000 Practical Formulas—The Best Way to Make Everything A book to which you may turn with confi- dence that you will find what you are looking for. A mine of information, up-to-date in every respect. Contains an immense number of formulas that every one ought to have that are not found in any other work. Price $4.00 Popular Science Monthly 225 West 39th Street, New York

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December, 1920 ing the driving sprocket to the shaft is shown in Fig. 4. The sprocket is bolted to a gear which is fastened on the shaft by a key or set screws. The belt pulley is eight inches in diameter with a 5-in. face. The rear wheels are 16 in: in diameter. Steering-gear details are shown in Fig. 2,.and the rear wheel fork-in Fig. 3. Fig. 6 gives a rear view RING SCREWED TO B, FIG.2 " DRAW-BAR © FIG3 Details of the steering gear and the construction of the forks of the rear wheels are shown here of the steering gear and also shows the position of the drawbar. If desired, a long crosspiéce can be used at the rear of the frame and the wheel forks attached to it 4 ft. apart so the machine can be used to cultivate between rows 2 ft. apart. The seat and the rear wheels can be obtained from old farm machinery. An air-cleaner must be fitted to the engine. One can be bought from a tractor dealer. This is important, as an engine which is constantly sucking SPROCKET BUSHING CF 5" PIPE . GEAR HZ yt mo aexy IRON AXLE FIGS These diagrams illustrate the method of fastening the driving sprocket to the shaft and give a rear view of the tractor - in dust will run for about a week and then be ready for a rest while new | cylinders and pistons are being fitted. A cooling fan is mounted on the right-hand outside frame piece. The fan can be driven from the belt- pulley shaft. The gasoline tank is mounted on scrap-iron standards on the center frame crosspiece as shown in the elevation.— CLIFFORD A. BUTTER- WORTH, Winter Weather Is Very Hard on Tires INTER-TIME is a hard period for automobile tires. Because of changing temperatures, standing in the freezing cold part of the time and kept in a warm garage at others, even tiny cuts in the tread are more apt to E.W. Puckett astonish vou. of students and graduates know Dobe salary. I train you personally. 1 as you would get it in a real job. I give you my And I train you until (now get the full A moaning of this) unt! you are qualified a first class draftsman and uniil or ina AF ane —- Lt . eae i and experienced as Send Coupon } forFree Book No matter what plans you have for the future. Get this great book—‘“Successful.Drafts- manehi Find out about the simply marvelous . opportunities. ahead now. How. the world needs _draftsmen; engineers; architects and builders. — What great salaries and possibilities there are! Send Pn for my book today. Chief Draftsman Dobe a 1369, 4001 Broadway, Chicago, Ill. notcher, HE IS SELLING GOODS OR SELLING HIMSELF. Se: Send today for the booklet, “HOW TO DOUBLE YOUR INCOME IN , 43x Xo, ONE YEAR.” It’s FREE—Use the Coupon. Fill it out and mail to Lo or THE PUCKETT METHOD CORPORATION CERF SF E. W. PUCKETT, President 354 West Wayne Street, Fort Wayne, Indiana MAIL IT TODAY >> rage every word and my hundreds pe ie promises. First about that $3,600 make you qualified to draw $3,600 per year like scores of ay other graduates aredoing. I give you practical drafting room work. Learn to Sell Yourself F SALESMANSHIP is the basis of all success in life. doesn’t mean that you must be a: Salesman, but it does mean that you must constantly use SALESMANSHIP i in order to get to the top in whatever you are doing. Every successful man has already learned how to sell himself—to sell his time, his personality, his talents, his energy, Don't be satisfied to be only fairly successful, It is easy, when PUCKETT METHOD OF SALESMANSHIP” reveals the secret so clearly that you can start straight toward the goal of success as soon as you center your attention upon v4. it. It costs you nothing at all to learn all about this F wonderful method of selling yourself at a fi I CLAIM THAT ANY MAN WHO WILL STUDY AND APPLY THE PRINCIPLES OF THE PUCKETT METHOD TO HIS “S. 4 LIFE FOR ONE YEAR, WILL DOUBLE HIS INCOME, WHETHER PAG Trained Until You Get Job That's My Offer- S ‘ofer Tknowh That’s the word for this greatest—most magnificent Drafting offer! I know-how far my offer inode all ay tery’ I Chief Draftsman Dobe Everything just man-to-man attention. FREE outs And more—I give you a whole set of drafting tools the minute you become my student. You get every tool Sool ype need. A masniicees $25.00 instruments with which to build wor success in Grottenemaio. “Rémember—the draftsman goes ay and up to the fabulous incomes engineers architects. “Chief Draftsman Dobe Dept. 1369, 4001 Broadway, Chicago Without ar book," Succesofu whatsoever please mail your man- ship”, and fu Il particulars ut your liberal “Personal Instruction” offer to few students. PIE. 3. cceveecestionweedea sevtideddevéctn NYS iH sotic asiibéokemenbeascnle sere eeesesese ees ees es eseeee~ This Be a top- you know the secret. “TH re whict. will

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aS ey {im ara ee ; a \1| sm) . C4 - a, iis = — WE pasos = ss fi Free Trial © you may have any instrument with complete musical outfit, for a week’s free trial at home, No obliga- tion. Return it at our expense after tria! if you wish. Outfit includes velvet lined case, self instructor, music andall accessories at factory cost. A tremendous saving. Convenient Monthly Payments lees diten ferlnmmen of uh, Werte Send Coupon for Beautiful New Catalog Every {instrument known {illustrated with price, easy terms and trial blank. Catalog absolutely free. Write today. The Rudolph Wurlitzer Co., Dept. 1789 117 E. 4th St., Gincinnatl 0.7829 S.Wabesh ca. - Chicago Send talog illustrated in color full de- tails of ¥ on eens Sutbte cod toon celal ard easy payment offer. * Name Address or (State instrument you are specially interested in.) men wanted everywhere. Big “Write Today ‘DIRECT FROM THE FACTORY TO YOU FOR $13.50 - This genuine waterproof raincoat, com- bining all qualities of the highest-grade garment, the final achievements in style, durability, ventilation, design and material, DIRECT FROM THE FACTORY TO YOU BY PREPAID INSURED. PAR- CEL POST. With the signing of the armistice and termination of our Government contracts, we found ourselves stocked with a large supply of material and, having lost our civilian patronage, we decided to sell PEERLESS RAINCOATS direct from the factory to you. Man’s model shown is double-breasted, with in- verted pleat down back, belt all around, buckled wrist fastenings, outside patch pockets, convertible col- THRU. AN IDEAL mas morning. of last issue regulation ARMY state chest measurement. Money Back Order NOW direct from Dept, 2, 80 BRANFORD PLACE NEWARK, NEW JERSEY lar and built so that NO WET CAN GET CHRISTMAS GIFT Here's your chance to geta bargain for yourself or an ideal Christmas gift for your rela- tives or friends. A gift of this kind is sensib':, inexpensive and bound to be appreciated by the recipient. Upon re- ceipt of your remittance and instructions, we will send a Peerless Raincoat direct to the desired person for Christ- We still have a limited supply RAINCOATS which we are closing out at $8.50. Also Woman's Model, $12; Boys’ and Girls’ Model, $7. Belted leatherette coats for men and women, $24. When ordering | Satisfaction Guaranteed or The Peerless Company AGENTS WANTED FA LEARN AUTOS AND TRACTORS | Wonderful opportunities constant- « lygoffered trained men; we train u thoroughly to start your own usiness or make good money as motor expert, driver, shop fore- man, etc. 5000 graduates making g00d. S Catalog Free. ~ Cleveland Automobile School, 1821 E. 24th St.,JCleveland, Ohio. ge Td Learn Piano! a eri 4) This Interesting Free Book fy shows how you can become a skilled player q Music | of piano or organ in your own home, at one ost. Dr. Quinn’s fae ing of te ‘Conservatories. ul 26 years. complete piece i: key, within 4 les: ‘understand. Fully illustrated. For begin- ners or teachers, old or . Al music . Diploma gran Write today for 64-page free book. ‘‘How to Study Music’’. M.L. QUINN CONSERVATORY, Studio ZL, 598 Columbia Road, Boston, 25 Mass. Every Bicycle a Motor Cycle By using a STEFFEY ATTACHMENT Fits any ordinary bicycle. truss. diamond or double- bar frame. Easy to attach. Thoroughly PRACTI- Sy CAL and SUCCESSFUL. Send stamp for circulars. Play chords at once an sons. Scientific yet easy to W entific Box- ing in your own home. ”” Thousands are now doing it. Just _ send me_ your name, age, occu- pation and address and I will send you my Free Book- let explaining ex- actly what my \ course contains. i Dept. W Gibbons Athletic ? Association Metropolitan Theatre Bldg. ST. PAUL MINNESOTA TS ARTY LY) | YS + 112 Popular Science Monthly develop into big holes than in summer. Particles of ice and snow will lodge in the little cuts, and when the car is put in a warmer: place, this ice will thaw, wetting the fabric and leading to a gradual disintegration of fabric and tread. When. the moisture again freezes, it serves to do further damage. Thus the alternate thawing and freez- ing develops small tread cuts into serious tire maladies. It is best to fill up all cuts with tire dough, keeping out water as much as possible. There are several excellent preparations in the market to heal tread cuts,-and if applied strictly according to direction, the cuts are effectively sealed against the deleteri- ous effects of winter driving over wet and icy pavements. How to Make an Overflow for the Drain-Pipe SIMPLE and effective overflow which removes the lower bad water without discharging the upper fresh water can easily be installed. It consists of the usual drain- pipe reaching to the level at which it is de- sired to :keep the water. Over this: pipe a larger pipe is fitted which extends a short ‘distance above the overflow. The lower ex- tremity has a large opening. The water en- ters this hole from the bot- tom, rises be- Two pipes set up in the manner shown will tween the outer enable you to get ridof and the inner bad water in the drain pipe, and, when it has reached the top of the shorter pipe, over- flows and is carried off in the usual way. This device is inexpensive and eas- ily set up without special tools, and farmers as well as dwellers in the suburbs will find it very useful. How to a ee Small Articles Quickly MALL articles, like expander pins, etc., can be quickly case-hardened by plunging them, at bright-cherry heat, into a box containing cyanide of potassium crystals, and then quench- ing the pieces at a dull-red heat. Cyanide of potassium is a deadly poison and should be handled with great caution. The operations of case-hardening should be performed in the open air, and the operator should stand on the side from which the wind blows. D

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December, 1920 eee PO NRE ELA RABE! AABEAELBEE “Keep Your Eye on Jim!” “It’s not alone what a man does during working hours, but outside of working hours—that determines his future. There are plenty of men who do a good job while they’re at it, but who work with one eye on the clock and one ear cocked for the whistle. They long for that loaf at noon and for that evening hour in the bowling alley. They are good workers and they'll always be just that—ten years from now they are likely to be right where they are today. “But when you see a man putting in his noon hour learning more about his work, you seea man who won’t stay down. His job today is just a stepping-stone to something better. He’ll never be satisfied until he hits the top. And he’ll get there, because he’s the kind of man we want in this firm’s responsible positions. You can always depend on a man like Jim. “Every important man in this plant won out in the same way. Our treasurer used to be a bookkeeper. The sales manager started in a branch office up state. The factory superintendent was at a lathe afew years ago. The chief designer rose from the bottom in the drafting room. The traffic manager was a clerk. a ane: CORRESPONDENCE SCHOOLS =i our Cat EBGinaen LSALESMANS HIP Elecerte and ADVERTISING a ae Retiweys Bh Wiadow Trimmer —_—o_— = —— === TEAR OU ee a I | Telesreoh Engineer Show Card Writer ‘‘All these men won their advancements through. spare time study | mEouaniea, VENGINEER Rilirosd Treiamen with the International Correspondence Schools. Today they are | M hine Shop Practice ce oa... earning four or five times—yes, some of them fen times as much | Ge Engin oy P money as when they came with us. | FSecveziag and Mapping Stcnographer and Typist “That’s why I say that Jim there is one of our future executives. Keep your ertinn ooee se Sere ncowunaant eye on him. Give him every chance—he’ll make good!” | [{Marine Engineer Railway Accountant Employers everywhere are looking for men who really want to get ahead. If you | RCHITECe. Soop ENGLISH want to make more money, show your employer that you’re trying to be worth Architecture! Dre Cutieer Common § Schoo! Subiece more money. If you want more responsibility, show him you're willing to prepare | Concrete, Kali yourself fo. it. | Seructural Eagineer Sstoabats Sitios For 30 years the Internationa Correspondence Schools have been training men ee ee once, and women right in their own homes after supper, or whenever they had a little | Bcnesst DORISULTURE a tho time to spare. More than two million have stepped up in just this way. More | Mathematics Pealtry Kalsing than 130,000 are studying now. Ten thousand are starting every month. Can you Name. afford to let another priceless hour pass without making your start toward some- | Present thing better? Here is all we ask—without cost, without obligation, mark and mail | Street aon this coupon. It’s a little thing that takes but a momeat, but it’s the most impor- and No. tant thing you can do today. Do it now! | City State. Canadians may send this to

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They work | naturally f and form |. no habit aD They work naturally and form no habit naturally and form no habit One twist of mouth piece cleans this pipe of smooth-smoking Italian briar. Aluminum draining canal does the trick. $1 postpaid; cash or money order. THE S & H COMPANY Wilkes-Barre, Pa. P.O. Boz 254. Do You Work in a Factory? $10 to $25 a Week for an Hour a Day We want a representative in every factory in the United States. You can easily earn $10 to $25 extra each week by using an hour a day of your spare time. Write to-day giving the name of the factory where you are employed. POPULAR SCIENCE MONTHLY, 225 W. 39th St., New York Make Your Single Sockets Double Workers Have a place to attach your Electrical Appliances without disturbing bulbs. Light and Power or Light and Heat from every single electric socket. At your Dealer’s fo? 350 Kt EAcH © “Every wired home needs three or more”’ BENJAMIN ELECTRIC MFG. CO. Chicago San Franc: Quality Dominant (a: New York isco You feel the need of exercise. You haven't time. 15 min- utes use of Pandiculator equals 2 hours in gymnasium. Gives you punch p, and vigor. The lazy man’s gym. 32-p. booklet FREE. The Pandiculator Co., 343 Advance Bldg., Cleveland, O. ARMATURE AND MAGNET WINDING By Horstman & Tousley A necessary book for electricians. Full facts and dia- grams, $1.75 postpaid. POPULAR SCIENCE MONTHLY, 225 W. 39th St., New York Make $10 to $30 per Day at VULCANIZING with Anderson Steam Vulcanizers. Better tire repair- ing and retreading at one-tenth the usual cost. Bi profits for thousands owners. We not only supply the Anderson Steam Vulcanizer and Ander- son Retreader, but we teach you how to use them, and how to build up a successful business in your town, with little capital. There are Anderson Schools of Vulcanizing in 33 states. There's oo eng one near you. rite and we will tell you all about it. : he course requires five to ten on and costs $35.00. If Jou buy an Anderson Vul- p canizer the course does not cost you a cent and in addition we pay $5.00 per day expense money because we sell the work you do while teaching you. Don’t miss this opportunity. Write today. ANDERSON STEAM VULCANIZER COMPANY 101 Williams Building Indianapolis, Ind., U. S. A. 114 Popular Science Monthly An Adjustable Handle for a Small Mirror HE illustration shows a novel arrangement for holding a small mirror securely. It is designed to be 4 PIN— A piece of tubing, a pencil clip, and a pocket mirror make an excellent arrange- ment for use about the machine-shop carried in the pocket and is invaluable for shop use. The handle is made of a piece of ordinary brass tubing. A small pin clamps the mirror at the top as shown. The bottom of the mirror is held in place by a pencil or fountain- pen clip.—J. W. Moore. How to Make Rings of Equal Areas IVIDING a disk into a num- ber of rings all having equal areas can be accomplished by a long and tedious mathematical process—if one knows how. But it can be done just as accurately and agreat deal faster with a ruler and a pair of compasses. Lay out the circle and draw a radius line— that is, a line mN from the center to the cir- cum ference. Constructing rings of Find thecenter equal area becomes a simple matter if you use this geometrical method of the radius and from that describe a semi- circle touching the center of the big circle and the circle itself. Divide the radius into as many equal spaces as the desired number of circles, and from each division point erect a line per- pendicular tothe radius and cutting the semicircle. Then proceed to draw the rings, each of which must cut the intersection of a line with the semi- circle. This done, all the rings will have the same area, and the area of the central circle will be the same as that of any one of the rings. If you wish to obtain exact results you will have to draw carefully.

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December, 1920 An Inexpensive Aquarium Air-Pump HEN animals are kept in a salt- water aquarium it is absolutely essential to aerate the water thor- oughly, to make it possible for the fish to live in it. For this purpose some kind of an apparatus must be procured. But these devices are all expensive and quite intricate in design. Therefore a man with a hobby for ' =: . eee es, Vee) aquaria and aquatic life will certainly / Ae Be : ee ae appreciate an apparatus simple in : ee Aa & a? aa | | construction and easy of manipulation. ort eilirt saenineiis My. im ¢ i. h, ‘ All that is necessary for such a a > . BI & \\ me pump are two large, heavy bottles both of the same size, some rubber tubing and glass tubing, two rubber stoppers, and three metal pinchcocks. Bore two holes in one stopper and three holes in the other, and arrange the tubing as shown in the diagram. The rubber tube C connects the faucet A This simple apparatus will efficiently solve the problem of aerating the water for your salt-water aquarium with bottle D. The pinchcocks are The water swirls | placed at G, E, and B. slotheetae dene Now let the water run into the bottle 8 motion four | D. The water will force the air from in the cana this bottle into the reservoir E. When washer. D is full of water, the faucet is turned , off, the pinchcock B is closed and G is opened. There is now one atmosphere in bottle F. When pinchcock E is opened, the water will be forced out of Au ——— 7 ~— bottle D through the long glass tube io age 0 : gleaming copper tub of the into the rubber tubing H and into the 1900. Out they come, snowy sink by the remaining pressure in the white and fresh as new, to bottle D. As soon as the water begins adorn baby’s chubby, pink to run out of the tube H, open cock E person / so that all of the water will siphon out of the bottle. The tubing J leads to the aquarium to be aerated. I'm the jigure 8! Pi oe EE nS Re TET Ta N fact, everything can be washed in the 1900, even heavy sheets or A tales Sellen OR tak cnly blankets. The cleansing, soapy water rushes back and forth through clean the water, but will keep it in the clothes in that magic figure 8 movement, swishing through them with circulation, which is a very impor- every motion of the tub! ‘This figure 8 movement is the magic exclusive tant consideration in a salt-water feature that makes the 1900 the perfect washing machine. aquarium.—ERNEST BADE. And there are no parts in the tub to cause wear and tear, or to wrench off buttons. The swinging reversible wringer works electrically, and the A Graduated T-Square for entire cost of running the 1900 is only a few cents an hour. When you Section Lining think of the 1900 remember that magic figure 8! : N drafting or engineering drawing, If you want to know more about the 1900, send for the interesting book, the process of section lining is very George Brinton’s Wife, a boox of fiction with some surprising facts included tiresome, especially as care must be sen ane create sass| IQOO CATARACT WASHER difficult task. A very simple yet efficient method | THE 1900 WASHER CO. Pre gen A ne es of maintaining accuracy in the spacing | 206 Clinton St., Binghamton; N. Y. $57 Yonge St., Toronto of section lines is to graduate the upper edge of the T-square to correspond 115

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Step Up toa Better Job! That better job and the bigger pay that goes with it—the job you want—is within your reach. It’s only a step to the really big jobs rom where you are. That step is simply ‘“‘knowing how.” The practical books for self-training descri _ will give you that “know how.” They are the by which you can reach the job you want. me of the best authorities in the world wrote these books in plain, everyday language. Anyone who can read and write English can understand them. Thousands of pictures, dia: s, ete., make difficult points as plain as day. Over 1,000,000 volumes have been eold, Pay-Raisin$ Books at Greatly Reduced Prices Automobile es tT 6 volumes, 2600 pages, ry and Contr en . Gaim gp rw $29.80 Carpentry an nm ay nm volumes, 2138 pages, "Too at Bonvod $37.50. cinubeebiebiphinsteccssterel ow 24.80 Civil Eneineering, ~- ee 3900 pages, 3000 pic- |___Fan RR ien aa: ow 39.80 Accounta and Business Mana yy" 7_vol- umes, pages, 2000 pictures. as $52.50. Now 29.80 Fire Prevention and Insurance, 4 volumes. 1500 pages, 600 pictures. Was $30.00..............cs0000 _ 19.80 Electrical Engineering, 8 volumes, 3800 pages, 3000 pictures. as $60.00... ‘Now 34.80 Machine gy yoo 6 volumes, 2300 pages, 2 2500 pictures, Now 29.80 Steam and Gas En wyincortng. 7 volumes, 8300 p 2500 pictures. ow 29.80 Law and Practice (with reading gouzaed, 13 aoe, 6000 pages, illustrated. Was $97.50................ Now 49.80 Tele ny and Teyesrenhy. 4 volumes, 1728 28, pictures, Was ow 19.80 Sanitation, Heating aa Venttioting 4 volumes, 454 pages, 1400 pictures. Was $30.00.............. Now 18.80 Drawing, 4 volumes, 1578 pages, 1000 pictures, bios prints, etc. Was $30 19.80 Send No Money Shipped for 7 Days’ Trial Write the name of the books you want on the coupon and mailit today. We will send the books at once, express collect, and you can use them just as if they were your own for a whole week. If you decide you don’t want to keep them, send them back at our expense, 75¢ a Week If you like the books, as thousands of other men have after examination, just send us $2.80. You can send the balance of the special _re- duced price the same way— each month (75 cents a week). Step up to a better job with bi Ker a4 MAIL THE COU- It’s your first step. AMERICAN TECHNICAL SOCIETY Chicago, U. S. A. Oe ANE NT EE TS CC ATT American Technical Society, Dept. XX-209, Chicago, U.S.A. | i nick caceasnbbennséncnenebvn l for 7 DAYS’ examination, shipping charges collect. [ I will examine the books thoroughly and, if satisfied i will nend $2.80 within 7 days a each month until I have paid the special price Of @..............0....scsessesseeesesesee If I decide not to keep the Sas I will return them at your expense within one week. | | Address,, | Ee eee i (Please fill out all lines.) with the desired spacing, as shown in the illustration. Except in very small drawings, sec- tion lines are never less than 1-16 in. apart. For general work, 3-32 in. is possibly the most practical distance for spacing the lines. The upper edge of the T-square should be divided into spaces of 3-32 in. for general work. An- other square | SPACES For should then SECTION LINING be placed OO alongtheedge —S= = of the T- ——— square, and lines, corre- Mh, aaete oa > onding 34 to . mi eins are ; the division great help in marks, drawing sec- scratched into tion lines its surface by means of some _ sharp-pointed in- strument. If any special spacing is desired for a certain type of work, that distance may be used instead of 3-32 in. Great care should be taken not to scratch or mar the working edge of the T- square, the lines being scratched only on top.—J. EDWARD WHITE. Improvising a Simple Level on the Job FTEN a rough leveling of some surface is needed when a large level is not available. The writer has often used the following scheme for leveling and found it to be as accurate as that obtained with a spirit level. Take two pieces of wood about 4 ft. long and nail to a short piece of plank, such as the two pieces D and E, and nail to the piece G. Nail a crosspiece F between the two legs as shown. Fasten a screw-eye to the piece G and hang from it a piece of string to which PLUMB From a few strips of lumber, a string, and a plumb this serviceable grading level may be made is fastened a plumb-bob or any heavy piece of metal or wood that will keep the string taut. Now place the frame in a vertical position with the two legs resting firmly on the foundation. Mark with a pencil the place where the string passes the crosspiece F at the point A. Then reverse the position of the legs upon the same foundation and mark at the point of the string intersection with F at B. Then take the rule and measure the distance between A. and B, and at the center of this distance make a permanent line C. Now when 116 Popular Science Monthly BE AN AUTOMOTIVE EXPERT! XPERT Automobile and Tractor Me- . chanics are in demand everywhere. Well trained men earn big money. YOU can qualify for these positions. We teach you by daily actual practice under skilled instructors. Experience in training thousands of mechanics for U. S. Govern- ment. Course include all branches of automobiles, tractors, welding and tire vul- canizing. Day or even- ing classes. Our free catalog tells how we train men to occupy ex- pert automotive posi- tions. Send for your copy now. Motor Institute, Inc, 2698 University Avenue S. E. Minneapolis, Minn. and tells the truth; now in its 28th year, This paper fills the bill’ with- eo We has become but $1 : year. If] the World’s Capitaland the Pathfinder is you want to keep You posted on what is is | like shies in the inner the * on the | council with those who a, snoid the eorid '3 destiny. @ or money, this is your means. a“ want a paper in your home Na Hons wx - oman reliable, entertain- ing. ‘i rr the Pathfinder is you would appreciate ‘a pa- typ ts e clearly, Ca ital: Ry a ioe to to fo show how that you might like such thfinder on tee Wine 10c does not repay ws, e are win ipa foyer in Sta tm. Washi Address De. AN EASY WAY TO MAKE MONEY -:: on a small salary, Be independent. Go in ny: a re pairing business. One man says “‘I made $60.00 the first Others average $200 to $500 a month. Very little capital needed. yy plentiful. Bn Syaterist & pos- sible customer. No experience need e teach you, SHALER Tire Repair Outi roved Wrapped Tread Method a Udy iy one “vulea: ning +o ne - boy can use it. It’s the only vulcanizer that has Automatic Heat Control, and can’t undercure or overcure a ‘tire. uires no watching or regulating. FREE Book aA, to Open a Tire Shop.** ells how to make money. Dow't delay. Write vo Boy Violin, Hawaiian Guitar, Ukulele, Guitar, Mandolin, Cornet, Tenor Banjo or Banjo Wonderful new system of teaching note music by mail. To frst Pupils in each locality, we give a $20 superb Violin, Mandolin, Ukulele, Guitar, Hawaiin Guitar, Sultan, eam, Sees a ieercunbeubes lately free. Very small charge for lessons only. We guarantee sac- harge. Complete outfit free, Write now. No obligation, SLINGERLAND SCHOOL OF MUSIC, Inc., Dept. 27, CHICAGO, ILL. Y DONT YOU we THe: “WORDS FOR A Sonc| wa. mee you ALONG mposing the music FREE and ublishin same. Send poems today. pl + LENOX vO... 271 W_ 125th Sty NX. )Golden Gem f Adding hoch rae » (ECE aye mented calculations | stationer. | rte Sou ro oe Trial ¢ }> Pd aaaese: ns WE n/t ine |e New ork Agency Agents wanted Crier og :

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December, 1920 the frame is placed upon a perfectly level place, the string should be in line with C. In leveling up surfaces it is only UL, pont THAT HOLDS 1TSf9 SHAPE necessary to get the plumb-line to Oo 00 OO intersect at the mark. When making $7-00 $3,00 39 == & $10 — SHOES the level, it is necessary to have the FOR MEN AND WOMEN two feet rest upon two surfaces, one to be considerably higher than the you ~— rig ed en other. The side legs may be of uneven th lengths and nailed together at any WANS lhe bestknown angle.—B. F, DASHIELL. : or OF ROV INS ae 5 aay inp 8 x world. They are {¥ sold in 107 W.L. ' Douglas stores, . direct from the factory to you at only one profit, which antees to you the best shoes that can be produced, at the lowest possible cost. W. L. Douglas name and the retail price are stamped on the bottom of all shoes before they leave the factory, which is your protection against unreason- able profits. W. L. Douglas $9.00 and $10.00 shoes are absolutely the best shoe values for the money in this country. They are made of the beet and finest leathers that money can buy. They combine quality, style, workmanship and wearing qualities equal to other makes selling at higher prices. They are the leaders in the fashion centers of America. The stamped price is W. L. Douglas personal guarantee that the shoes are always worth the price paid for them. The prices are the same everywhere; they cost no more in San Francisco than they do in New York. W. L. Douglas shoes are made by the highest paid, skilled shoemakers, under the direction and supervision of experi- enced men, all working with an honest y C wi} determination to make the best shoes for 3) exp HUIS» the price that money can buy. = Cm Oey, SSM (= uN OO MN Qi ines Un) W.L.DOUGLAS SHOES a MASTERPIECES F SHOE DESIGNING J Mi ua! Old Materials Made This Useful Forge HE man who made the forge shown below uses it often on his ranch, where he does all his own blacksmithing. The forge is made entirely of old materials. The fire-pan was made from the bottom of an old cookstove. Two legs 30 in. long, made of 2 by 2 in. lumber (rescued from the kindling- pile), and two legs 42 in. long, made from 2 by 4 in. stuff, are securely braced. A sheet-iron guard placed on * tz : 4. ay TAU NMA AENEAN UR EDERSALLUE OAL Wg —™ 4" HOLES SRS OH CIRCLE OF SMALLER HOLES este aa ean C ¥ w; ae METAL BOX OR CINDERSPIT CETTE CAN SUV SLIDING DOOR @ ‘W. L. Douglas shoes are for sale by over 9000 shoe dealers besides ourown stores. If your local dealer cannot supply you, take no other make. Order direct from factory. Send for booklet tellinghow toorder shoes by mail, postage free. This forge, made entirely of old materials is the clever invention of a rancher 124 Spark Street, Brockton, Mass. © stamp le. Be fire-pan helps to control the fire. —— ee ae: = @ Sale. > covetul to io see The fan is made like the fan of | gqgqqqqmmmunununnnuunnnununininN fanning-mill, and is contained in a metal-covered drum which confines an the air current and carries it to the Youc Save ‘$50 sone o metal box that serves as a cinder-pit, gute top frame yourself. ° UTI — ving W.. President one end and part of one side above the las shoes. winekt meen brripg WD plai ainly $7// asic ss a Co. We make these recovers to x * the top being bolted to the fire-pan. $8.46 sivts etme ofan | | fl Notwithstanding that there Care must be taken that this joint is Para pestPld isetreetons: ‘Roof snd quar: | | Fae eg different kinds of an airtight one, as immediately above || iie'same: rear and model number of rout areaneol R.. 1- ¥ ee ee roca this metal box are the perforations in || LIBERTY TOP & TIRE CO.. Dept. ES. Cincinnati, o.| | | viable reputation for quality the fire-pan for the draft. \/e",) and serbice or given so much The bottom of the cinder-pit i| a= | satisfaction to closed with a sliding metal door. The om AA. large wheel was taken from a worn- EA OK A out washing-machine and belted to a KH ‘LVS small pulley on the end of the fan- Be PG Se oO SIE 2. SoZ shaft. A three-point lever carries a aA SOEi SE cx OE little pulley which acts as a tightener Reo’ Cluster Metal Shingles, V and is held taut by a coil spring. free: Sinus. Waltearas Faint, Sai vanieed Rack. The metal used in the drum and at tock Bo oe ee metal box is old 12-gage black iron, Edwards “‘Reo’’ Metal oo taken from old smudge-pot covers cost less; outlast three ordinary roofs. No painti that had gee their days of useful- ao ness.—R. D. SHULTIS. Why ? Because the webbing of fresh live rubber feels better and wears longer. teed rot, fire rust, ligh A Mirror Aids in Placing New Phonograph Needles . ARIOUS makes of phonographs on the market are so built that | faniDs Mare. Co. Sampies & the reproducer cannot be turned Roofing Book

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aa eben oe ee peices meena NPE EINER ma ARENT DRT IN me Tn NEY meee, HHA

manners nye teenfeenme Teen nt Ys Sn Ht be Poona Pee se iit tw — wn pa ae ac A a Tate Ze hristmas GIFTS Saw * CREDIT | AN XS J - Sa. Wl $145% wt s : - > f-0 - & As} a ft 4 Pe oR ? a. \ cd

2325- #302 Illustrations in this adver- tisement are reduced in size about one half. A postcard brings our Cat- alog 273 Send for it Today, addressing Dept, 273. ‘“ROYA 10 Months to Pay The Royal Way HORTAGE of ready money need not prevent ou from giving your oved ones the Xmas Gifts they long for —buy on Credit. The cost of a cheap, tawdry,imitatiengift will go far towards the payment of a enuinearticleon The oyal Credit Plan. Rare Xmas Values We have a large stock of the most beautiful and desirable Diamonds, Rings, Watches, Toilet Sets and other Gifts. These are rare Holiday Values at amazingly low prices. Buy Now For Xmas The Xmas rush and consequent mail conges- tion will soon be upon us. Make your selec- tion NOW and to be sure of getting exactly what you want on time, you can buy now as well as later, for in buying the Royal Way, you have Ten Months to Pay No money in advance. Order now—pay 20% upon examination and balance. in ten equal monthly amounts. See and examine any selec- tion. Then, if pleased, send first payment and the balance in easy monthly installments. Money prompily refunded onany unsatisfactory pur- chase, if returned within 10 days. Liberty Bonds accepted. 10% discount allowed for cash. New Royal Catalog FREE Send for it TODAY Dept. 273 Describes and illustrates in beautiful halftone re- production, all of our rich values in exquisite Xmas Gifts. Tells ex- actly how to take ad- vantage of our confiden- tial credit plan. Low Prices We buy in large quantities and give you rock bot- tomprices. Lower than you could buy for cash from your jeweler. Order At Once to get the advantage of thesewonderful Xmas bargains, WATCH co, ESTAALISMEL

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DIAMOND ©) 35 Maiden Lane - New York

around and up so the operator can see to put in a new needle. Instead, he has to feel underneath for the needle socket and put the new one in by that means. This difficulty can be relieved by placing a small pocket - mirror on the top of the cabinet so it will be di- rectly beneath the reproducer when it is brought back in the starting position previ- ous to placing THAT TTT TTT

By looking in the mirror you can see the needle onanewrecord. socket and easily insert Then, by _ the needle looking in the mirror, when the reproducer and tone- arm are raised, the needle socket can be seen without having to twist your | neck out of shape in an attempt to look up from underneath. If desired, the mirror can be set permanently into the cabinet by gouging out a socket for it in the wood and securing it in place with screws. A Sacking Device that One Man Can Operate NEW device for holding sacks during filling should save backs and a lot of useless adjectives for one compelled to work alone. It consists of half a pickle barrel with the end knocked out, andattached tothe

The barrel holds the sack and serves as funnel side of the bin or granary where most convenient with asmall block of wood. Five or six nails, driven through the sides of the barrel from the inside and pointing at an upward angle when the barrel is in place, holds the sack in position during the filling. The sack is pulled up over the bottom of the bar- rel as shown, and the nails hold it. This should be at the right height from the floor to allow filling of the sack, and yet so that the sack will touch the floor, preventing any weight from coming on the nails and causing tearing.—DALE VAN HORN. 118 Popular Science Monthly es ay Why use = —=s in a hee = Wood? ae turnavalve to cook or heat THE OLIVER OIL-GAS BURN Does away with coal and wood — Cheaper. Makes your stove or range a gas stove. Gives more heat. Keeps your e warmer. No fires tomake. No ashes, dirt, amoke, odes. chopping,

shoveling -- ing coal or wood. Sa mary your Po ott bake bett. better, =, “fm i. : @ over stove, simply oe fre bes box, casily, sipped fn'g in [x phy y abeoket ely safe. Lasts lifetime Coal-oil (kerosene)

-_ meal owt ven even wy 2 instantly, t whether you “burn ‘coal or ‘wood, | "Sold r mone arantee trial, Wane fer” FREE li literature and. special introductory price. AGENTS WANTED (References Required)

— No . loney eH, it re Typewrite the NEW Way Totally new system based on mastic Finger Tremng” practicedaway from — See First shows a Send postal for 32 page plains why New Way ae bringyou — spee rie accuracy, Increased salary. Write NOW

10 Easy Lessons

when to use gna vainly. ina in Ts in sextettes, or band; how Send free Saxaphone book and ey ee ee BUESCHER AND INSTRUMENT CO. Block, Elkhart, ind. '$Music Lessons | -UNDER MASTER TEACHERS

A Complete Conservatory Course B Mai a home i music tennene gubee erican and European te Ss. — rsed by Paderewski. Master teachers guide ‘and coach one Lessons a marvel of simplicity and completeness. Any Instrument or Voice 23 course Jou are interested in—Piano, Hi ’ Music, Violin, Cornet, Mandolin, & i —and we will send our FREE CATA el) ins vocal courses, UNIVERSITY EXT ENSION CONSERVATORY 6332 Siegel-M: yers Bidg. _ Chicago.

Dece up : use. time whi half well that loac tire teni wee con tak oe ee ee ee ee ee Oe el ne

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December, 1920 An Automobile Jack that Is Quick Acting T is possible to prolong the life of automobile tires if the car is jacked up as often as possible when not in use. During the night, and at other times when the car is in the garage, which usually represents more than half of the time, the car might just as well be raised from the floor, saving that much weight on the tires. Extra’ load is not only removed from the tires, but any tendency toward flat- tening of the shoe and making its wearing qualities uneven is lessened considerably. A set of homemade jacks will not take long to make, and once made and put to use, wiJl much more than pay for themselves in a few months. The construction of the jacks is simple. A 6-ft. length of strap iron 34 in. in thickness and 1 in. wide is re- | quired for each jack. This is bent | nearly double in the center, and each | end provided with a right-angle turn and four inches turned to slightly more than right angles with the length of the jack. A block of wood, prefer- i lon Ags FIRST SECOND POSITION POSITION These four jacks will relieve the tires of the weight of the automobile Sw ably hard wood, is cut from a 2-by-6 about 10 in. in length, and a notch cut in one end as shown to fit the under side of the. wheel-hub. This is then bored for a 44-in. bolt an inch from the other end and holes to match drilled through each side of the jack at a height which will place the bottom of | the notch on a level with a point about the center of the wheel-hub. It will be necessary to taper the block to fit the two sides of the jack and allow the bolt to be fitted tight. The feet of the jack should be spaced far enough apart so that each can be placed on one side of the tire. The illustration shows how the jack is used. The first position shows the feet of the jack placed tight against the tire with the notch of the wood block against the under side of the wheel. When the top of the jack is pushed in toward the wheel, the action raises the wheel about 2 in. and trans- fers the weight from the tire to the hub. The feet afford sufficient bearing to enable the car to stand rigidly when four jacks have been applied and remove all possibility of its shift- ' | | i floor.—DALE VAN Horn. . ing to one side and back to “a He feels the relieves rheumatic | aches and pains EEP Sloan’s Liniment ik handy to put the “feel good” back into the sys- tem. All it needs is just one trial—a little applied without rubbing, for it penetrates—to convince you of its merit in relieving rheumatism, sciatica, lumbago, neuralgia, lame mus- cles, stiffness, bruises, pains, backaches, strains, and the after-effects of exposure. ets quick The congestion is scattered, Warming relief promptly, cleanly, without 7 effort, economically. You be- come a regular user of Sloan’s 35+ Liniment, adding your enthu- 70+ siasm to thousands of other friends the world over, who keep it handy in case of need. At all druggists. applies with- out rubbing pours Sloan's into palm ie / “DON’T SHOUT” “T hear you. Ican hear now as wellasanybody. ‘How?’ With THE MORLEY PHONE. I’vea pairin my ears now, but they are invisible. I would not know I had them in, myself, only that I hear all right.” The Morley Phone for the DEAF is to the ears what glasses are to the eyes. rtable, weigh and harmless. Abyone can adjust it. Over one hundred thousand sold. Write for booklet and testimonials. THE MORLEY CO., Dept. 797. 26 South 15th Street, Philadelphia. HIPFITTERS, Structural Workers,Carpenters, Bricklayers, Mechaaics ,Ptumbers, Pipefitters, Boilermakers, Sheet Metal W can earn more money if they know how to read Blue Prints. By our method, we train you in a short time. Write for sauane B. ee trade. We also teach Drafting. a tsman! Earn money. Books and tools FREE, Write for ~ Gc COLUMBIA CORRESPONDENCE SCHOOL Eat. Dept. 43, Drexel Bidg., Phila., Pa. 1904 f 119 Established 1810 110 Years of Making

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evstincnrra etiam emery ps merurenrmvienicerentataaeennietiy Terapeintnpearmnctsee et aapenieerertmeare Ses tamer its So EE a Ae NE I ER ETL “When Jo has the Groust That’s eg a cough with a vy a so hurry for usterole and rub it in sight over the chest and neck. How it will tingle at first and then grow ever so cool. And how it will - reach in and penetrate ri nt to the s It will sipate al the stuffy con- estion which causes that cking cough. Why shouldn’t grand- mother swear by Musterole for colds and coughs? It is betterthan amustard plaster as that was in the ol days. And the explana. tion is this: Musterole is made of oil of mustard and other home simples. it penetrates under the skin, down tothe part. Here it generates its own heat, and this heat disperses the congestion. Yet Musterole will not blister. Musterole, on the contrary, feels delightfully cool a few seconds after you apply it. Try Musterole for Bobby and Helen and Dorothy’s croup—and for your own cough, too. Try it for rheumatism—it’s a regular router out of all congestions. Always keep a jar handy. Many doctors and nurses recommend Musterole, 35c and 65c jars—$3,00 hospital size. The Musterole Co., Cleveland, Ohio BETTER THAN A MUSTARD PLASTER WARNER'S “scromaric> 32 “THE CAL PISTOL =e That is cheats eee Hits QUICK ae oe vee —s wGattoebest and sare at least JAM \camaad Ss & @ & & $5 Get a Warner “infallible” Automatic and teach the women how to plug the bull’s eye. Target shooting is intense, exciting Sport Excellent training for nerves and eyes. Teaches self ay ee contidence and familiarity = weapons. ooter Says :‘‘ Your ‘infallible’ Pistol ae ar aes you claim and more. I put a shots in bull’s eye one inch in diameter at distance of twenty-five feet with the pistol. The accuracy of this arm is unsurpassed by any regardless of price.’ . S&S. Hoffman, 157 Oakwood Avenue, Orange, N. J. FREE LESSON OFFER An authority has prepared for us, a set of six lessons on the Art of Pistol Markmanship. These lessons are of marvelous value in the use and care Of a Warner“‘infallible’’ Automatic. Write today for illustrated cir- cular and terms of Free Lesson er. KIRTLAND BROTHERS 96 Chambers St. ( Dept pf ) Con inc. New York How to Throw Lines Over High Objects ECENTLY, in line construction, workmen had occasion to get a very small line over high wires. The line which was to be sent over was, of necessity, very light, and some means was necessary to get it over without breaking. The thread at- tached to a stone, if thrown over, might injure the glass win- dows on either s de, and so the job was done in the following fashion: Two gallon- can covers were procured and the two held together with the rims outward. The thread was knotted and the knot wedged between the two disks and the rest, some hundred feet, coiled about the rim. This was held in the manner shown and easily cleared the wire in ques- tion.— DALE VAN Horn. rim of two can-covers, and you will easily throw it over a high wire Make a Safety Spark-Plug Carrier Box OW often has the motorist carried his spare plugs in the tool-box rolled loosely in an old cloth, only to find in an emergency on the road that the spark-plugs have shifted about in the tool-box with wrenches, etc., and every one has a broken porcelain insulator? The illustration will serve to show how this is overcome. This carrier box is made from three pieces of wood the coverofwhich piece of wnee TUBE is made from Ascot a few inches of an old inner tube. Drill out the largest piece of wood that is to take the screw por- tions of the plugs, the di- ameter being such that the threaded end can be screwed in, making its own thread in the wood, which should be quite soft. After passing the plug down with a wrench the first time, the impression will be plain enough to render further use of the wrench unnecessary. The end pieces are not in the way of the fingers when one is inserting or re- moving a plug, and they afford pro- tection to the plug porcelains and terminals. C pLUG THREADED IN Spark-plugs may be safely carried in a carrier like that shown here 120 Coil your string about the , You can easily learn Modern Ballroom Danc- ing now in your own —no matter where you live—by the famous Peak System of Mail Instruction Fox-Trot, One-Step, Waltz, Two- Step and latest Ballroom dances taught. Courses constantly revised to include the newest dance ideas. We Guarantee the Peak System to teach you to be an easy, graceful and accomplished dancer. Equally successful with beginners and with dancers seeking to improve, and learnthe latest society steps. New Diagram Method: Theresult of forty years’ practical experience. , Easily and quickly learned. Thou- ~~ ~"™ sands taught successfully. I can teach you. Send Today for FREE Information: Write at once for surprisingly low offer. William Chandler Peak, M. B., President The Peak School of Dancing, Inc. Established 1880 Room 116 821 Crescent Place Chicago Shoot Without Noise Qvoid Gomerbonee. 3 Giackine. njoy quiet shooting, a anytime. Use the new ffodel 190 1926 MAXIM SILENCER Price, .22 cal. $7.00. Gund 6c in stamps for catalog and BOOK. LET of astonishing experi- ences of Silencer users. 91 Homestead Ave. Hartford, Conn. and ttre ter ts and mice. ets : c's die ein a. house.” 3,200 mek of the % K. W. 1 bone ee a eT type vgs oo power, large overload capac safety” ty spark aap ate are we of Packard you will pm ra t ——— a under govern- Write forour Bulletin on bowed Transformer. Warren, | WirelessIransformers New Big Wo, 1420p. Wises | and 100 pp. Electrical Catalog Wireless catalog —~y" for 12¢ and electrical catalog for 6c. You may deduct this amount on first $1.00 purchase. Catalog not sent other- wise. Anby wireless amateur will tell you itis the one catalog to have. As an encyclopedia of information it is invaluable. The largest and most elaborate radio catalog pub- lished. Values that cannot be duplicated elsewhere. THE WILLIAM B. DUCK COMPANY The William B. Duck 212-214 Superior St. TOLEDO, OHIO

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December, 1920 A Lard-Can May Be Used to Dry Fruit in HE common 50-lb. lard-can, which may be bought at almost any grocery for forty cents, can with a very little work be converted into a cook- stove evaporator for the drying of fruits and vegetables. With three circular trays that fit inside, it has a capacity of 10 lbs. or more at one filling, and when a steady fire is kept in the stove, the drying will be com- pleted in five or six hours. Such cans are from 12 to 15 in. in diameter; the trays may be made of simple wooden hoops with bottoms of wire screening like that used in a coarse sieve. Six inches from the bottom of the can four holes are punched in the side and strong cross- wires put in to support the bottom tray. The other trays are each supported by cross-sticks that rest on the tray beneath. In the top of the can and also around the side near the bottom, a number of small holes are made to provide for a free circula- tion of heated air through and about the trays of fruit. The bottom of the can may be cut out or it may be left as it is without any difference in the results. HOLES IN TOP. WOOD HOOPS \WIRE SCREEN iii : : 76 pul \(reer Lae

TWO CROSS WIRES CROSS STICKS’ A lard-can makes an ex- When the —cetient’ fruit dryer or traysare filled evaporator. Three cir- withthesliced cular trays fit inside fruit and placed in the can, the material in the bottom tray, being nearest to the ‘source of heat, will naturally dry first. When this is removed, the next tray above is placed at the bottom. Then the first tray should be refilled with green fruit and placed on.top. Thus the fruit in the trays encounters increasing temperature as it is moved down each time, result- ing in a more uniformly dried prod- uct than when left in one position. An evaporator of this kind will take up little room on top of a range, and the drying may be done while the stove is used for baking; a few hours every day. The product will be much superior to that dried in the sun, and no damage will result from insects.—H. F. GRINSTEAD. A Quick Way of Tightening Loose Flywheels T is common practice for the me- chanic who undertakes the job of tightening a loose flywheel, in instances where the flange of the crankshaft is bolted to the flywheel web, to ream holes in the flange and fit larger bolts. : Instead, he could save time by

For “DAD” and the BOYS QOMETHING you would never thinkof! An inex- pensive gift giving year ‘round comfort to the man who gets it—the Parkroger Collar But- ton Gift Box, containing four of the famous

| Renee meee neeneccmll’ ATMS “"PARKROGER ABSOLUTELY ONE-PIECE COLLAR BUTTONS The man who receives this gift doesn’t miss trains hunting collar buttons, or find himself suddenly without one. He has a button always at hand. Remember these are the famous PARKROGER ABSOLUTELY ONE-PIECE Collar Buttons. Made ofa single piece of metal, gold plated on both sides. Base can’t wear loose and come off as with other buttons. PARKROGER Buttons can’t stain or poison the skin. The Gift Box sells for $1.00 at all jewelry and men’s furnishings stores. PARKS BROS. & ROGERS, INC. Providence, Rhode Island Makers of the famous JIFFY LINKS Separabie Cuff Buttons

)— BY eG Florsheum _. e SHOE }§ WE cannot afford to make disappoint- ing shoes, and you cannot afford to buy them. Our reputation is worth too | much to us; and your comfort, satisfaction | and money are worth too’ much to you. i We've kept on turning out Florsheim rE quality—you can keep on enjoying it. Iv te» i» a» eth» ie

= Consider the wear not the price \ per pair. Look for the name— N The Florsheim Shoe. Write for \ booklet “Styles of the Times.” ~ i = Cal CE = > + ent eh» aa» ab, « AO « a ~ l= > ~<A == OE «ak kG -e e , aae

4 ten ests THE FLORSHEIM SHOE COMPANY Manufacturers Chicago

The Rainbow—Style M-55

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fos encase thin ate ett mh eH ay naee Sm sion aheacaminolenanlalibt-in agers i ad 6a ey ON Mat ON Mi a reheat

ABill-Fold for Every Purpose You can put system in your pockets with an “American Gentleman” bill-fold. It com- bines neatly and compactly 12 features that are useful every day. (See picture.) Strongly made of genuineleather. Stitched through- out, no edges pasted. Choice of black or tan. There is a distinctive look to the “American Gentleman”, It is a bill-fold to be proud of. Buy one for$1.50 at any deal- er’s. Or send$1.50with your dealer's name and we will mail you one postpaid. Charles K. Cook Company, Inc. Dept. D, Camden, N. J.

Dealers—write for profitable dealer proposition Makers of Cigar Cases

[earn Mechanical Drawing EARN $35 TO $100 A WEEK AS AN EXPERT DRAFTSMAN We will train you by mail, in your own home through our practical Home Study Course in Mechanical Drafting. By our imp’oved method you will learn Drafting as you would in actual practice in any big drafting department. When you finish this course you will be qualified, as an experienced draftsman. to step into a position paying $35 to $50 a week to start with oppo-tunities for advancement to position of Chief Draftsman paving $5,000 or more a year. he practi- cal knowledge of drafting which we will give you may prove the stepping stone to position as Chief Engineer or Mana~er of Production at a much higher salary. Our graduates ae alwaysindemand. Big cone eras employ them regularly at ood salaries. because they KNOW—because we produce rst-class professional ae A ay WRITE TODAY FOR FREE CATALOG telling what we have done for others and w hat we can do for you. It will open your eyes to Your Future in Drafting. ROY C. CLAFLIN, Pres., COLUMBIA SCHOOL OF DRAFTING, Dept. 1204, Washington, D. C.

wi 55 90c an Hour Introduce “‘Sodereze.” A new wonder. A wy, pure solderin paste iorm. Workslikemagic. isp Stops all leaks. For mending water buckets, ¥ cooking utensils, milk pails, water tanks, tin roofs—everything including granite waro, y i, agate ware, tin, iron, copper, zinc, etc. Quick Sales—Nice Profit Everybody buys. Housewive, me- chanics, electricians, jewelers, plumb- ers, tourists, automobilists, etc. No leak too bad to repair. Just apply a = little *‘Sodereze,” light a match and that’s all. Put upin handy metal tubes. Carry quantity right with you. Write for sampleand special proposition to agents. AMERICAN PRODUCTS CO.,2:2:2 American Bldg., Cincinnati, Ohio

reaming this flange with a quick taper reamer, trimming a bushing for each bolt, and boring to fit the old bolt with the outside of the same taper as the reamer. One saw-cut is made through

PLAN VIEW DETAIL OF TAPER (O) BUSHING eel 724 SHAFT FLANGE YeSAW CUT HOLES TAPERD WITH oe |

The bolt pushing down the bushing pulls the crankshaft flange tight against the flywheel and holds it permanently the bushing, allowing for expansion, and then the whole is screwed up, set- ting up snugly occasionally by tapping lightly with a hammer.—P. P. AVERY. Roll Your Ladder Instead of Carrying It HAT is the use of carrying a long ladder on your shoulder or dragging it through the streets when two small wheels fastened to the legs near the base will make it a wheel- barrow? The illustration shows how a painter put to further use the rear wheels of a worn-out express wagon, original- ly belonging to his young son. The wheels were left on the squared axle, | which was just long enough to reach across the bottom of the

Wheels on that clumsy ladder. The ladder enable you to axle was secured push it about easily with two light : strips of strap iron fastened in the manner shown.—DALE VAN HORN. To Protect Automobile Tires and Tubes HE automobile tire and its accom- panying inner tube are the vital parts to be considered on a long tour or in the usual day’s run. To keep them for use in emergency cases on the road is a thing to be appreciated by all owners and drivers. A few suggestions are well worth considering, inasmuch as they are offered from practical ex- perience. To keep the inner tubes safe and free from injury during driving, they should be protected against moisture, dust, and grit, as these affect them to an unlimited extent. To prepare a tube for storage, remove the valve- 122

Popular Science Monthly Hang Pictures on Needle Points. By a simple twist of the wrist, place Pictures Charts or Drawings, on any surface with Moore Push-Pins Glass Heads—Steel Points

x Harmonize with any color scheme; can be used over and over. For heavy Pictures, Mirrors, Hanging Bookshelves, etc., use MOORE PUSH-LESS HANGERS, Brass finish. “The hanger with the twist.’ Samples Free. Sold everywhere by Hardware, c per Stationery, Drug, Photo Supply l pkt. and Department Stores. MOORE PUSH-PIN CO., 11-12 Berkley Street, Philadelphia, Pa.

iibondes Sor comfort Every pair Sei inats

MADE AT SHIRLEY M ASSACHUSET

Send Us Your iin and We’ll Send YouaLachnite Don’t send apenay. dost say: “‘Sendmea Lachnite mounted in asoli goldring on 10 days’ free trial.’’ —— a mail it prepaid right to your home. When it - r ey F fal ae Mg mey pomeed the ring f or ays. ua, OF any friends can tell it from a diame it back and we will’ return your deposit, But if you decide to buy gaa ag te until $18.75 has beenpaid. Write Today $573 polid gold ri gold ring 3 Fing yoo @ arias Indice ee men’s). Be sure to "Harold Lachman 204 Se. Pearia Su, Dep. 1789 Chicago 1 LAV 7 BECOME AN LL.B. an is the only law school in the U. S. which conducted a ndard resident school and gives its students or ae oo | the same instruction by mail. We are legally qualified and authorized to confer the of Bachelor of Laws— B.—by correspondence. Over 450 lectures deliveredin classrooms and especially revised for our students aa alarge corps of prominent, practicing lawyers. Our Law Library consists of 24 volumes ‘bound into 12 books) of Students” ard Text Books, pre: at an enormous cost exclu- sively for the use of our students by one of the largest and most reliable law book —e in America. Written guar- antee to prepare gradua pass bar examination. 00 course in Oratory and Public Speaking given free. Thousands of successful graduates. of its kind in America. Established in 1910. Write today for Il for ae omy Catalog which will give you the Facts— the Proof— the Evidence. Hamilton College of Law, 507 Aaecrmi Bidg., Chicago “Lighting Fixtures” Ready to hang. Direct from manufacturers. Completely wired including glass- ware. Send for new No. 18 catalogue. ERIE FIXTURE SUPPLY CO. Desk A, Erie, Pa.

We pay $7.00to$18.50 and upa pair and express charges. Big Profits. We furnish guaranteed high grade stock and buy all you raise. Use backyard, barn, cellar, attic. Con- tract and Illustrated Catalog Free. STANDARD FOOD AND FUR ASS’N 407C Broadway New York

fe e2

SHAW MFG. CO., Dept. 4612 GALESBURG, KANSAS

Page 107

December, 1920 spring and -plunger from the in- side of the valve-stem, and roll the. tube up so that all the air is expelled. Holding it still compressed, re-insert the valve-plunger and screw it up tight, after which, screw on the valve- cap. The tube then will lie absolutely flat and should be folded as shown in the illustration, and an elastic band made from a strip cut off the end of an old inner tube around it, as shown. One at each end will make a complete job. The tubes should be carried in a wooden box with corrugated card- board tacked to its inside walls. An ordinary skate-strap will be best for locking the box. The tires are the next in line. To be kept in first class condition a tire should be kept in a position as near its real diameter as possible, and to pro- vide for this a rack should be made on SECOND OPERATION eG=lea—, Fl RST OPERATION ZY | F a> = RUNNING-BOARD Lz) If your spare tires and tubes are taken care of as described in this article, you _ will have no trouble from them the running-board of the automobile to hold the tires. The illustration shows a few suggestions as to how this may be done. To make either one of these, use ordinary gas- or water-pipe 1 in. in diameter, with an elbow and long nipple on the one for the spare wheel, and a T and flat-iron bracket with several holes for up-and-down adjust- ments for the spare-tire bracket. This accommodates tires from 30 in. to 36 in. The difference in size is taken care of by raising or lowering the bracket on the T and replacing the bolt. Secure the tire by a heavy leather strap passed through the ends of the bracket. Fasten the flange to the run- ning-board by bolts.—P. P. AVERY. Polishing and Weatherproof- ing Brass Surfaces OR quickly scouring and yolishing and, at the same time, weather- proofing brass a preparation is recom- mended, which is composed of three parts of oxalic acid dissolved in forty parts of hot water, to which are added 100 parts of powdered pumice-stone, two parts of oil of turpentine, twelve parts of soft soap, and twelve parts of fat oil. Shake well before using. ACCOUNTANT $7,000 TO $15,000 AUTOMOBILE ENGINEER $4000 TO $10,000 123 That is what Albert Foster wrote us eight- een months ago, and he goeson: “I’m tired of being bossed for $25 a week. I wanta He-Man job with real pay. I want to get into the $100 a week class. Tell me how to do it.” We showed him how. Today he has a He-Man job and He-Man pay. We tell of his experience because it’s typical. WHAT ARE YOU? A man who is up and doing, getting real money, or are you simply marking time on $25 or $30 a week? $100 jobs don’t go begging. If you want one you’ve got to go after it. Are you satis- fied with your present condition in life? If you are, we have nothing to offer you, but if you want one of these real jobs with big pay, then we can help you and help you in a hurry. A REAL MAN with a real man’s pay is what you want to be, and we will show you how. Without loss to you of a single work- ing hour, we will show you a sure way to success and big pay. A large number of men in each of the positions listed are enjoying their salaries because of our help —we want to help you. Make a check on the coupon against the job you want and we will help you get it. Write or print our name on the coupon and send it in today. oo will be under no obligation. American School of Correspondence Dept. G-975 Chicago, U.S. A. Ue oe (IMERICAN SCHOOL of CORRESPONDENCE Dept. G-975 Chicago, Il. Explain how I can qualify for position checked : 3 —Architect — Accountant and Auditor — Steam Engineer $5,000 te $15,000 $2,500 te $7,000 $2,000 te $4,000 e ——Building C Draf and Designe, — Foreman $5,000 to $10,000 $2,500 to $4,000 $2,000 to $4,000 q — Automobile Engineer ——Electrical Engineer —— Photepisy = $4,000 to $10,000 os $4,000 te $10,000 $2,000 te $10,000 a a ike en at Ed — Sanitary ee i ae $2,000 te $5,000 —Civil = —ehs ——Telephone Engineer 7 000 te $15,000 ~7*$5,000 te $15,000 $2,500 te $5,000 Fl e 5 Enek Seechenical Engincer __Telegragh $4,000 te $10,000 $4.000 to $10,000 $2,500 co $5,000 ca a i Manager —~. Shep Superintendent —.. igh Schoo! Graduate a $5,000 to $15,000 $3,000 to $7,000 in two yeare — » Public A A —.Fire insurance eS $7,000 te $15,000 $4,000 te $10,000 | $3,000 te 310,000 Name § @ Address bd (cence camcancancocancaneasommomeds Pe SM hi OO SIS nn Sl 2 at i i — roses

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yma Seal i i aa ENE ae Paine ames Ne PE SPCR

i Ns /

AUTO - - WHEEL SAILING. What fun you'll have with this new amusement. Attach a Fae «| sail to your Auto-Wheel Coaster %, or Auto-Wheel Convertible Road- : ster. The roller-bearings are the a same as _used on automobile

wheels. That’s why the name **auto-Wheel” means so much. The Auto-Wheel carries 1000 Ibs. The roller-bearings will not crack or chip as old-fashioned bali-bearings do. The November ‘Auto - Wheel Spokesman”’ tells how to make a sail for your Auto -Wheel wagon. Send for it. Organize an Auto- Wheel Club FREE caps to members. Special Captain’s cap. FREE Auto-Wheel ) Bank. Just send names of three coaster dealers in your town, a which ones sell the coaster with the name “auto - Wheel" on the sides.

a Coaster Co.Inc.. Sled _ 157 tae Stree N. TONA WANDA, N.Y. In Canada: Preston, Ont. Export Office: 365 a Ee Street, New York

NTH a RIDING AROUND-— Railway Traffic Inspection is Easy, Pleasant Work. Travel—broaden your- self—something new every day. Hun- GET PAI dreds of men needed. You are ready after 3 months home, spare-time study. Position Guaranteed. Any Man Over 18 Years Old can put himself into this responsible profes- sion. Earn $110.00 monthly to start, all expenses paid. Steady, fascinating work with bigger rewards ahead. No books to buy. Moderate fee prepares you. Money refu wre 4 position not secured. YOU TAKE NOR “acest NOW Profession is still young with many fine op- portunities. Make your decision now, this minute, to send for all facts and judge for yourself. Send for Free Booklet D-221 Standard Business Training Institute Buffalo, N. Y.

EARN ENGINEERING Expert electrical engineers are being paid

fabulous salaries. Thousands needed to- day. Wegive you. personal and thorough training — practical, technical, courses three months totwo years, under expert engineers in electricity, steam, gas, auto, armature winding. drafting, etc. Extensive laboratory and shop equipment. Nota trade school. Enroll anytime. Do not judge us by size of ad but write for free illustratedcatalogue, FINDLAY ENGINEERING COLLEGE Greatest of its kind

001 indlene Avenue Kansas City, Mo! Ciwif__-...._ 7

Refinishing Shoe Toes that Are Cracked or Worn HEN the “boxed”’ toes of shoes get scratched or scuffed so that the ordinary polishing will not restore the original appearance, a great im- provement can be made by applying shellac. Rub the shellac on with a rag and rub it off again, so that there will not be a

Y i — ~~. . ee ee le Ue he

When shining seems to do your shoes no good, perhaps some shellac rubbed into the toes and heels will brighten them up thick coat. If necessary, rub on a second coat when the firstisdry. This will not affect future polishings. ° Shellac cannot be applied where the leather is subject to bending, as it will crack; but on the stiff toes or heels it is very satisfactory. Brass Tools for the Making of Fillets N making patterns for castings an important point is to make all inside angles rounded or ‘“‘filleted’”’ in order to avoid the tendency to start a break at a sharp angle. An excel- lent way to make these fillets is to use a mixture of putty and shellac press- ed into the corners and smoothed off to the re- quired radius. Thisisa sticky mix- ture, and about the only kind of tool that will work with it is one of polished brass, The end of the tool should be spherical. Good tools can be made for this pur- pose by mounting polished brass balls, such as are made for valve seats and the like, on steel rods with handles. The diameter of the ball will determine the radius of the fillet. 124

FILLET _ PATTERN

The filleting mixture is pressed into the cor- ners of the pattern by this instrument Popular Science Monthly ehte am Cet ea Kana Gifts Now Only are ry cents a day ay) No Money i JUST send yourname and address for our 128 pase Christmas book of argains in diamonds, watches and jewelry. Millions of dollars worth of jewelry from which to choose your Xmas gifts. Your selection sent on your ee ; uest, without a pen own, If you don’t think it 4 the biggest bargain have ever seen, sen “it back at our expense. If 78 keep it you can pay at the rate of only a few cents a day. 8% Yearly Dividends Youareguaranteedan8% yeerlyincrease in value on all diamond exchanges. Also per cent bonus privilege. Write Today for Xmas Catalog Send your name and ad- dress now. No obligation. on Charge coon > is great collection ° Se men a J MLYON ee 1 Maiden Lane, New York N.Y.

Build This Car This nif! BL what 5 y little car

TYPEWRITER EMPORIUM C FREE CATALOG Siv6 ano Wcnetr in cuss, ii Either pin illustrated made with any 3 letters s) and 2 figures, one ortwo colors enamel. Silver plate, 250 ea., $2.50 doz. Sterling silver, 50% ea., $5.00 doz, Write for new catalog. . io BASTIAN BROS, CO. 287 Bastian Bidg.,

+ Rochester, N.Y,

o> FIBRE LIMB soothing to your stump— strong, cool, neat, light. Easy payments. Braces ¥ for all Guaranteed 5 Years deformi- Send for Catalog Today. ties.

$4 or $5 wit’Buy A Standard, Guaranteed

em With Every Modern Writing Convenience Write Today For Iustrated Circular Explaining Try-Bcfore-You-Buy Plan SMITH TYPEWRITER SALES CO. (Harry A. Smith) 306 —218 No, Wells St.,Chicago, Uli, DEAFNESS 1S MISERY I know because I-was Deaf and had Head Noises for over 30 years. My invisible Antiseptic Eas S Drums restored my hearing and ogee Head <a * and will do it for you. They are Tiny Mega Cannot be seen when pg Effective when ee is caused by Catarrh or by Pertorates, Partially or Wholly Destroyed Natural Drums. BL to Rut ine easy to take out. Are “Unseen expensive. Write for Booklet and my pal statement of how I recovered my hearing. 4. O. LEONARD Suite 301, 70 5th Avenue « « New York City

Ponular Smoenre Manth):

as

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December, 1920 Discovering Worn Insulation in Automobile Wiring HERE are some very simple devices that one may make at home that greatly simplify the lo- cating of short circuits, open circuits, “‘grounds”’ in the various wires on the automobile. The device herewith con- sists of a pair of ordinary awls, a wire loop, and a test lamp. The object in view is to bridge over the imperfect electrical circuits and in this way locate them. Each of these awls are to be connected to the AWL> TESTLAMP (AWL ghost circuits and other electrical troubles can easily be located with this CABLE BEING TESTED testing device wire with a lamp, as shown, that will indicate whether the circuit is broken or complete. The points of the awls are to be inserted through the insulation of the wires under test. It should be remembered that in the testing of wires where there is no current in them it will be necessary to provide some means of supplying [ current, and batteries connected to this device serve to accomplish the end in view.—RONALD L. PRINDLE. An Easy Way to Take Bitter Medicine EDICINE that is disagreeable to take can be swallowed with a minimum of unpleasantness by using the simple apparatus shown in the accompanying illustration. A piece of glass tubing, corked at The wire holds the tube of medicine in the glass. Upon tip- | ping the glass, the SY, medicine flows down | your throat with the water one end, is suspended by a wire in an ordinary glass. Water is placed in the glass and the medicine in the tube. Then the patient drinks the water, and the medicine pours into it as it goes down, and is hardly tasted. Any clean wire may be used for the purpose, but for sanitary reasons it is preferable to use silver or nickel wire, which resists corrosion. Bits Hope seh Y SS) V~ / SG Tat 7 rtsOf Men | ii MY rare = BOOK | Ae 7 ee PROVESA | COEKENS . EVELATION 1 TO You" EALTH. oy Sait INN 1 Neg AW AZZ My Appeal Is Not Only To The Hopeless But To All Who Want To Be Well And Strong WANT every man who is at all unhappy, who lags behind in the procession, who fails to attract the opposite sex— I I want them all to try Strongfortism. done for thousands. you. I know what it has I know what it can do for others—for I honestly seek to help you—to help the whole world— by putting into the hands of as many human beings as possible my wonderful tried-out-and proven system, knowing that I will be blessed and acclaimed by everyone who guides by the simple rules of life I lay down for men and women. I Come To You With Encouragement Whether you are or suffering from STRONGFORT The Perfect Man SEND FOR THIS BOOK Right Away I know I can confer upon you in- estimable benefits—that’s why I want simply wrongly-nourished, or over-worked, indigestion or constipation; or one of the many feeling they are condemned to a life of misery and despairing of ever being happily married or just an over-worked brain-fagged business man—I come to you with hope and assurance, confident that I can build you up into a human being that will have the right to feel he is ‘“‘in the image of his Maker.” The Strongfort System accomplishes its marvelous transformations in men without the use of drugs or medicines and without in- terfering with your every day mode of living. You'll Feel Better Day By Day I will guarantee you will feel better, be better from the day you adopt Strong fortism as your mode of life. And day by day you will feel a new life, an awakened spirit, growing power, an increasing desire to be up and doing, an ambition to achieve —in other words the feeling of health and power and manliness—the feeling that is Godlike, the right of every man—the thing that raises the human being above the brute. FREE CONSULTATION COUPON Absolutely Confidential Me. Lionel Strongfort — Dept. 137, Newark. N. J.; Personal—Please send me your book ‘PROMOTION AND CONSERVATION OF HEALTH, STRENGTH AND MENTAL ENERGY,” for postage on which I enclose a 10c. piece (one dime). Send me special information on subjects'marked X below, without in any way obligating me. to give you an insight into my won- olds ig tee ere > Radaiaiindiiciaias derful method by sending ye my . --Sqterrh Ben ne f Bee Strength, highly interesting and valuable booklet : “Asthma : Billo usness ne Felling Ha “ec : . , ty Pos -. Wea Promotion and Conservation of Health, | sstnine " tsafeeciae’ | thge’™ i oe nness e ervousness ee a ea: Strength and Mental Energy. ‘ , ..Rupture |.Poor Memory . Round Shoulder Don’t lose a minute. Sit right a ‘ } non pees ” -Luna Troubles 4 . tis .- Gastritis .. Fema rder down, clip the coupon in the corner of *‘ Noureigta .. Heart Weakness. "Weak Back this message and mail it witha 10c. .Flat Chest ..PoorCirculation .. Muscular . ; . : | Deformity .. Increased Development piece to my address. I will act (describe) Height . . Advanced Course promptly—you'll devour the truths .. Insomnia . Successful . Healthy Children found in my book and you'll seeat once § ‘Flat Feet that a new era of life is within your . Short Wind Marria . Manhood Restored . Easy Childbirth Here mention other subjects not listed above PS gts ete fr Ns RR a ea oe LIONEL STRONGFORT Siac dete cchaew aout COnendek chndnee erat Physical and Health Speciali st “sae ; eee eee TT Qecmpeiivine is icasiescic esas Dept. 137 rewemg PU. Be Bagi... coke cccse ce Mlblbelec eesareiekea es 125 i] | I i 4 i | }

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eo ater O38 Se SS en cant eM i ee oe carbene aoa Electricity Learn at Home There is a wonderful opportu- nity right now for boys who like electricity. Boys who are ambi- tious and will train themselves in Spare time can step into good posi- tions and get experience that will give them a real start toward suc- cess in life. Good salaries are offered with rapid promotion. For 30 years the International Correspondence Schools have been training boys for success in electricity and over 200 other sub- jects. They will help you prepare ‘right at home for a position in the line of electrical work you like best —or in any other work that ap- peals to you. Thousands of boys, through I. C. S. training, have stepped into fine jobs, but never were opportunities so great as now. Let the I. C.S. help you. Choose the work you like best in the coupon below, then mark and mail it today. This doesn’t obligate you in the least, and it will bring you information that may start you on a successful career. This is your chance. Don’t let it slip by. Mark and mail this coupon zow. — —— ——= == ==TEAR OUT HERE = «— «—e coe oo INTERNATIONAL CORRESPONDENCE SCHOOLS BOX 7605 B, SCRANTON, PA. Explain, without obligating me, how I can qualify for the position, or in the subject, before which I mark X. ELECTRICAL ENGINEER Electrician Electric Wiring Electric Lighting Electric Car Running Heavy Electric Traction Electrical Draftsman Electric Machine Designer Telegraph Expert Practical Telephony MEOHANIOAL ENGINEER Mechanical Draftsman Ship Draftsman Machine Shop Practice OHEMICAL ENGINEER SALESMANSHIP ADVERTISING MAN Window Trimmer Show Card Writer Outdoor Sign Painter RAILR OADER ILLUSTRATOR DESIGNER BUSINESS MANAGEMENT Private Secretary BOOKKEEPER Stenographer and Typist Cert. Pub. Accountant Toolmaker Traffic Management Gas go Commercial Law CIVIL ENGINEER GOOD ENGLISH Surveying and Mapping MINE FOREM’N OR ENGR ARCHITECT STATIONARY ENGINEER CIVIL SERVICE Railway Mail Clerk Architectural Draftsman Textile Overseer or Supt. PLUMBING AND HEATING AGRIOULTURE Spanish Sheet Metal Worker PoultryRaising Freneh Navigator Automobiles Italian Name = bs 7-26-19 Present Occupation oe Street and No. City State - The Microphone Will Enable You to Hear a Fly Walk ITH a tramp, tramp, like the footfalls of a regiment of soldiers, a fly goes walking along; with a roar like the shouting of some mighty giant, the faint murmur of a human voice is reproduced; far away from the scene a person listens to the plans of a secret conference. These things and more may be accomplished by the use of the micro- phone, that instrument which was so | useful during the war in detecting enemy submarines, in discovering raid- ing parties and in revealing secret mining enterprises of the enemy in No-Man’s land. Contrary to what might be sup- posed, it is very easy to make, and if there is access to a wireless or tele- phone receiver, the cost is little or nothing. From much experimenting with microphones of all kinds I have BATTERY PENCIL LEAD | RECEIVER CARDBOARD SOUND-REFLECTOR If you have a telephone receiver you can easily make a sound magnifier with a few odds and ends found that the instrument described in the following paragraphs is one of the best, both for simplicity of con- struction and effectiveness. The only materials needed besides a receiver are a cigar-box, a piece of pliable cardboard, an electric-light or battery carbon, the lead from a pencil, and the blade of an old knife (the blade from an old case-knife will do very well). The first thing to do is to procure a large and deep cigar-box and remove a thin piece all around the top of the box. - with the exception of a piece at each of the corners which are to be used as legs. Then turn the box upside down and make a groove in the top so as to fit and glue in the knife-blade. A few inches from this place the electric- light or battery carbon. Next cut the cardboard and glue it to the cigar-box. This acts as a sound- reflector while the cigar-box turned upside down acts as a sounding-board. The microphone is now practically finished. All that remains are the connections, which are very simple and can be easily made as shown in the upper illustration. When everything is properly connected, put the receiver 126 Popular Science Monthly CAN YOU think of a simple, practical idea that will fill one of the many re- quests we have on file for new inven- tions? It may mean a fortune for you. Thousands of things are needed RIGHT Now. Your brainscan help. Send to- day for our great new book—“‘Invene tions and Trade Marks, Their Protection and _ Exploitation’’ and learn more about making money from ideas than you ever knew before. It tells many things that are wanted, too. A postal will do— it is free. We help our clients, PATENTS seach uke AY ADVERTISED none others possess. — For SALE FREE Beene In INVENTION And book at once. MANUFACTURING SUPPLEMENT. AMERICAN Published for the man with an idea INDUSTRIES, INC. Send for free sample 201 Patent Dept., copy. One year’ssub- WASHINGTON, D. C. il scription 50c. To the Man With an Idea j I offer a most comprehensive, ex- perienced, efficient service for his prompt, legal protection and the development of his proposition. Send sketch, or model and description, for advice as to cost, search through prior United States patents, etc. Pre- liminary advice gladly furnished with- out charge. My experience and familiarity with various arts, frequently enable me to accurately advise clients as to probable 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 Woolworth Building, New York City ib cna BOM hi Sih OE eis WRIA. ei “WILLIAM C. LINTON Consulting Engineer and Patent Attorney “Inventor’s Adviser’’ Mailed free on request. Gives full information as to Patents, Trade Marks and Their Cost OFFICES 364 UNIVERSITY ST., Montreal, Canada. PATENTS TRADE-MARKS COPYRIGHTS Send for our free book of patent information Beale & Park 25. S:cstinnen.2. ¢ 916 F ST. N. W., Washington, D. C. ~ How to Make Wireless Instruments A little book that fully describes the construction of spark wireless instruments and apparatus. Just the thing forthe amateur. Illustrated. Price, postpaid, 25¢. Book Dept., Popular Science Monthly 225 West 39th St., New York City weeaeam om ot & =e 4 _ —_ a Bee eee 6 | lO

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al

as described above. 127

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dias winliamrenineeuritncinelons ese enaE EO TET IT AAS SER Y SE NTE Sates et a POCPLUDUDAUTAUOADAC EUAN EULA AUHAT UATE EAU POT eee ee eee ee eer TC AMC EM Tei ULL banuuls 1222 PATENTS PROMPTLY PROCURED TRADEMARKS REGISTERED Send disclosure of invention, design, or trademark for actual search of U. S. patentsand novelty report. Validity and infringement investigations. Patent and trade-mark suits prosecuted and defended anywhere in the United States. Discriminating clients appreciate my efficient service. No literature will be sent you, as this is a professional service. information and advice given regarding each individual case. Specialize in prosecution of pending cases that have been previously rejected by the Patent Office. Specialize also in unfair competition litigation before the Federal Trade Commission. George P Kimmel. Master of Patent Law ANAOYANULANTEUDANELNETATEUUU TAME UTAH S Individual and Personal. Specific Z NDUUUUAEQUUUCLOOLUOCTONUOAYUUTENUOOUUHOUUOU PANU TAPPED HA SOUNNOANNATUOUUUAFUUUUADUUNAAUAUUUU TUE PATENTS F YOU HAVE AN INVENTION which you wish to patent you can write fully and freely to Munn & Co. for advice in regard to the best way of obtaining protection. Please send sketches or a model of your invention and a description of the device, explain- ing its operation. All communications are strictly confi- dential. Our vast practice, extending over a period of seventy years, enables us in many cases to advise in regard to patentability without any expense to the client. Our Hand-Book on Patents is sent free on request. This explains our methods,: terms, etc., in regard. to Patents, Trade Marks, Foreign Patents, etc. If you are a reader of SCIENTIFIC AMERICAN you are probably aware of the fact that it has a special appeal to the inventor. Each issue contains a description of a large number of recently pat- ented inventions. Pending pat- ent legislation as well as the most recent rulings of the Patent Office and the courts are considered in its columns. MUNN & CO. SOLICITORS OF PATENTS 683 Woolworth Building, New York 624 F Street, Washington, D. C. Tower Building - Chicago, Ill. Hobart Bldg., 582 Market Street, San Francisco, Calif. - —--—- a a es Book on Patents Before applying for a patent write for a Free Copy of our: book ‘‘How to Obtain a Patent,” which contains valuable information and advice to inventors. Ittells how to secure Patents. Send a model or sketch of your invention for our ‘‘Evidence of Conception” form and our opinion of its patentable nature—Free. Twenty: years’ experiencein patent matters. Write today for your FREE BOOK. 4849 Talbert Bldg., WASHINGTON, D. C. LL ll ls A a i en ll ti I. T. S. Patents Five years ago, practically without capital, J. G. | Tufford, Elyria, Ohio, and his associates Smith and Ingwer started business with the now well-known | I. T. S. Rubber Heel under the Tufford U. S. and foreign patents obtained through Lacey & Lacey. Fourteen tons of these heels are now produced daily. The profits already amount to many hun- dreds of thousands of dollars and foreign patents have been sold to the extent of $550,000.00. That demonstrates the financial possibilities even of an extremely simple invention of merit properly patented. Read PATENT-SENSE “dhe Book for Inventors & Mfrs” By Return Mail FREE. Write } LACEY LACEY. Dept.u-s ARMATURE AND MAGNET WINDING A necessary book for Electricians. By Horstmann & Tousley diagrams, $1.75 postpaid. Popular Science Monthly Full facts and 225 West 39th Street, New York Earn $2.00 per $2.00 an Hour hour in your Spare Time. Write Subscription Manager, Popular Science Monthly, 225 West 39th Street, N. Y. PATENTS SECURE A PATENT, send for Our Guide Book, HOW TO GET A PATENT, sent Free on request. Tells our Terms, Methods, etc. Send model or sketch and description of your invention and we will give our opinion as to its patentable nature WIE. opiceecittee ate necsiaetecoae RANDOLPH & 8, SAMMI sce cihnceensioeonsnilcedl 130 F St, N. W., | Washington, D. C. naa ee MEADE i caeasdinntbal IF YOU HAVE AN INVENTION and DESIRE TO LEARN HOW TO ee eee Popular Science Monthly ment when it is turned, so the me- chanic must govern himself accord- ingly. Ordinarily only a very slight bend should be made. : A Safety Clip for Your Spectacle-Case OW many times have you carried your spectacle-case in an outside pocket, only to have it fall out and break the glasses when you bent over? This is a very costly habit and one that can easily be avoided if you will adopt the following idea: Obtain a pencil clip, one of the ordi- nary kind will do, and flat- ten it out with a hammer. Then bend the two edges in- ward and drive these two ends through the cover of your spectacle-case, clamping the two ends as soon as they are inside the case. With this little device the case can be slipped into any pocket and clamped tightly by the clip. Best of all, it won’t drop out and cost you good money for new glasses.—J. W. MOORE. SECTION Attach an ordinary pencil-cllp to your spec- tacle-case and prevent it from dropping out of your pocket A Novel Way of Locking a Garage Door LOCAL automobile dealer utilized the angle-iron on the edge of his garage door to form part of the locking arrangement. The hasp was fastened 1 the inside heSR eee DOOR CLOSED i Push the hasp through a slot in the angle-iron from the inside of the door and make the locking. arrangement much stronger T of the door and in locking was pushed through a slot in the angle-iron. The padlock was then secured as shown in the illustration. Of course, this method can be applied only to sliding doors of the type most in use at the present time.—JAMES M. KANE. — ime cc ew eee a OUlCOe

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December, 1920 Making It Easy to Work with Limit Gages HEN using the gage shown in NV the illustration, the mechanic need not know the dimensions to which he is working, and often does not. He is told to make his work sufficiently small to pass one of the limits and too large to pass the other. He may not care what the real value of the dimensions is, and yet the system of gaging has proved remark- ably accurate and resulted in greater speed of production than when the attempt is made to work to a single known dimension. This is not strange when we consider that no measurement can be abso- lutely correct. The best that can be said of any measurement is that it is a close approximation. Even if a piece of work were absolutely correct one The machinist is told to make his work sufficiently small to pass one limit of this gage and too large to pass the other limit moment, the changes of temperature would cause variations very shortly. Besides, obtaining a correct measure- ment costs time and money. It can not be done in a few seconds, even approximately. Therefore why at- tempt the impossible? That is about the conclusion which has forced itself upon the minds of scientific men. Experts are required to make expert measurements, and hence it has been found more profitable to have the experts set the gages than to leave such work to new and perhaps inexperienced hands.—H. C. RIDGELY. Don’t Perfume Your Artificial Ivory ADIES are attracted to the beautiful imitation ivory toilet- ware now sold extensively for toilet- table accessories. 9 Unfortunately, perfumes have their place also on toilet-tables. Perfumes contain a high percentage of alcohol. In order to avoid mental anguish over the marring of her beautiful hairbrushes, mirror-backs, combs, hair- receivers, and so on, she should under- stand that alcohol is destructive to the surface of her “ivory’”’ toiletware. Imitation ivory is a product of cot- ton. It is a pyroxylin plastic and is attacked by alcohol. There is a cleaning cream on the market especially intended to be used on artificial ivory. It will remove slight scratches and stains and restore the luster of dulled surfaces, but perfume is apt to permanently discoior the articles and forever ruin their beauty. Reports Of Secret Service Operator 38 LEARN HOW THE MODERN DETECTIVE SOLVES THE MYSTERIES OF TODAY These reports are more interesting than fiction. They show you Human Nature RAW, NAKED and UNMASKED—exactly as it is. They give you INSIDE details on actual cases, show you exactly what the detec- tive did, hour by hour, and how he worked on the motives of men and women to solve the problems intrusted to him. These reports are FREE. Geta set at once, study them at home and learn what to do to fit yourself to take up this fascinating profession, and, as a trained, experienced operator Make $5,000.00 to $10,000.00 a Year Modern Secret Service work requires a knowledge of Finger Print Science. This is a splendid profession in itself offering great opportunities to live men and women. : a3 oe ee by our seesliied, a course—AT sain r e guarantee your success in this study by a CASH BOND, and you should lose no time learning about FINGER the brilliant possibilities it offers you fora PROFESSIONAL PRINTS CAREER. With the establishment of country-wide Bureaus, as endorsed by the Big Identification Associations, thousands —* of Bureau Chiefs will be needed at fine salaries. Get the FREE reports and our big FREE book describing this profession—at once. Write TODAY. University of Applied Science, Desk 9209, 1920 Sunnyside Ave., Chicago, III. Please send Reports and Book on Finger Prints, at once, sealed, prepaid and FREE. gab AI ORY, To be successful, whether on the farm or in the city, you’ve got to know motor mechanics. Our highly skilled master mechanics give you a practical, ‘‘horse sense” big shop training instead of a one-man course. You learn—by doing—everything about the care, repair and operation of auto, truck, tractor, stationary gas engines and aeroplane mechanics. No text books or unnecessary lectures. No education or experience necessary. No age limit. Learn Here in 7 Weeks Our big shop standard methods give you thorough complete training in shortest time. You can stay as long as you want. Learn where you work with the most modern equip- ment and motors of the latest design, including the Liberty Motor. Our Test and Trouble work alone is worth the price of the entire course. Our graduates are recognized everywhere as exceptionally competent workmen. Thousands are holding fine positions or making money fast running their own garages. Life scholarship privileges— further instruction, help or information about new developments in gas motors at any time, without extra charge. White students only accepted. Special Business Course or a thoroughtraining in modern methods of shop records and management as part of regular course. Y. M. C. A. Membership to students —swiming pool, boxing, wrestling, etc.—no extra charge. Send for it today. It tells all tani = Frank D. Hennessy, President — Iowa State Auto & Tractor School 769 Nebraska Street, Sioux City, Iowa “The Quality School’’ Pronounced by Official Inspectors - “One of the best in the country” é , 4 ° é LJ $ + «ité E-, ’ A TRACTOR OPERATIO Hennessy Iowa State Auto & Tractor School (3) 769 Nebraska St. , SiouxCity,lowa Please send FREE Book een as ace rina Os : President & Manager * I A RS ce

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~ ae abbas < SLA Am NT cent PRN eNO OL TS ARN, TA MRIS 6 hee RR te Pmt r a

HIGH SCHOOL COURSE IN TWO YEARS You Want to Earn Big Money! And you will not be satisfied un- less you earn steady promotion. But are you prepared for the job ahead of you? Do you measure up to the standard that insures success? For a more responsible position a fairly good education is necessary. To write a sensible business letter, to prepare estimates, to figure cost and to compute interest, you must have a certain 7 amount of preparation. All this you must be able to do before you will earn promotion. Many business houses hire no men whose general knowledge is not equal to a high school course. Why? Be- cause big business refuses to burden itself with men who are barred from promotion by the lack of elementary edueation. Can You Qualify for a Better Position We havea plan whereby youcan. We can give youa complete but simplified high school course in two years, giving ou all the essentials that form the dation of practical business. It will prepare you to hold your own where competition is keen and exacting. Do not doubt your ability, but make up your mind to it and you will soon have the requirements that will bring you suc- cess and big money. YOU CAN DO IT. Let us show you how to get on the road tosuccess. It will not cost you a single working hour. Weare so sure of being able to help you that we will cheerfully return to you. at the end of ten lessons, every cent you sent us if you are not absolutely satisfied. What fairer offer can we make you? . Write today. It Costs you nothing but a stamp. American School of Correspondence

American School of Correspondence Dept. H-975 Chicago, Ill. Explain how I can qualify for positions checked. ... Architect. — 000 to $15,000 "$5,000 to $15,000 .. Buildin, Contractor. .-.-Mechanical Engineer. 5,000 to $10,000 $4,000 to $10, ...Automobile Engineer. .... Shop Superintendent. $4.000 to $10,000 $3,000 to $7,000 ...Automobile Repairman. ees < 000 1 Fi G00 $2,500 to $4,000 |‘ ...Civil Engineer. --.. Steam Engineer $5,000 to $15,000 000 to $4,000

-.. Structural Engineer. ....Foreman’s Course. .000 to $10,000 $2.000 to $4,000 pe Manager. . Piston Writer $5.000 to $15,000 A to $10,000 ter cone Public Account- -- Sanitary oo $7,000 to.$15,000 7 to $5,000 a. te: ahd Auditor. .--. Telephone omy $2,500 to $7,000 $2.500 to $5,000 ...Draftsman and 00 to $4,000 -.. Pelegraph Engineer. ...Electri linet H h School Grad gpg ect - ig 00! uate. 41000 to $ $10, 000 Inu two yours.

Mamaia a ucation. ne In one year. $3,000 to 10,600 Rake ok, Cocco ees 0<600cnccceseeeees

Popular Science Monthly Have You a Step-Saving House? The Popular Science Monthly will pay ninety dollars for the best answers OW do you save steps in your home? What arrange- ments or what appliances have you made that save time and reduce work’ that would otherwise have to be done by hand? The Popular Science Monthly wants to know just what practical and useful things can be constructed to make every house a step-saving house. For instance: a con- cealed laundry chute would interest us, if it weren’t so old; a space-saving cupboard—another old one. No patented or marketed appliances will be considered. The Popular Science Monthly offers three cash prizes— a first prize of $50, a second prize of $25, and a third prize of $15—to be awarded in accordance with the rules set forth below. Rules Governing the Contest . (1) Contestants are not limited to the number of step-savers and. time-savers, but only one method can possibly win the first prize, only one the second, and only one the third. The contest is open to everybody. (2) The method must be shown clearly either in’ a photograph or in a drawing. If a drawing is sent in, it need not be made by a skilled draftsman. It is sufficient that it should be _ intelligible. While pencil sketches will be con- sidered, contestants are requested to-make their drawings in ink on heavy white paper. The views should be sufficient in number to set forth the writer’s. idea very clearly. The contestant’s name and address should appear on each sheet of drawings. (3) The - drawings -or- photo- graphs must. be accompanied ‘by ~—— - a description, preferably type-. written, in which the method is | clearly given. It must be written on one side of the paper only, and it should not be more than 500 words in length. The name and address of the contestant should - appear in the upper left-hand corner of the first sheet of the written description. (4) The drawings and descrip- tion entered by contestants must be received by the Popular Science Monthly not later than 5 p. m., on Friday, December 31, 1920. (5) The judges of the contest will be the editors of the Popular Science Monthly. 130 (6) The first prize of $50 will be awarded to the contestant who, in the opinion of the judges, has suggested the best method for saving steps in the house. The second prize of $25 will be paid to the contestant who sub- mits a method next in merit. The third prize of $15 will be paid to the contestant who sub- mits the method third in merit. (7) The winners of the contest will be announced in the earliest possible issue of the Popular’ Science Monthly. A description of the methods which win:the three prizes offered will duly appear in the pages of the Popular Science Monthly, together with the names of the winners. (8) The editors of the Popular Science Monthly shall have the . Tight to publish meritorious:manu- scripts which do not win a prize. . The -regular space rates will be paid to the contestants who sub- mit the manuscripts thus selected. (9) When a contestant submits more than one method, the de- scription and drawing by which each is set forth must be sent as a separate unit. (10) Manuscripts or drawings will be returned to contestants if stamps are enclosed. (11) Send drawings and specifi- cations to the Editor of the Step- Saving House; Popular Science Monthly, 225 West 39th Street, New York City.

Decei

A T b ee ae eS ae a ee ee

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December, 1920 A Light-Reflector from a Tin Can HEN a reflector is wanted in a hurry for use: with:-an incan- descent light, one that will serve the purpose very well can be made from an old tomato can. In fact, the result is rather surprisingly good if the can is If You are an bright and clean inside. Simply split A tin can makes an excellent reflector. The can is simply split open and turned back Apprentice— You take your problems to the STAR- RETT BOOK FOR MACHINISTS’ li peli It helps you to solve them. But, if you’ve completed your time. and are a MACHINIST—the old problems no longer puzzle you, but there are new ones that DO. They’re answered in Volume II of -this series, THE STARRETT DATA BOOK FOR MACHINISTS. Four editors, each an expert in his field, have selected its tables and formulas. “es. Gear-cutting feeds, power transmission =m . data, strength of materials, etc.—you'll find these and many more in. its 180 pages. Bound in red Athol leather. Size 41% x 7. Price 75c. Get either of them at your dealer’s, or order directly from us. Catalog No. 22 ‘‘W”’ is a handy reference the can down one side, cut out one end, and in the other end make a hole into which the lamp socket will fit tightly. Turn baek two wings from the split. Set them at the angle that seems to throw the light best. That is all there is to it. The illustration shows the idea quite clearly. Finding the Right Key Made Easy OME time ago I was put to the daily necessity of using two latch keys to reach and enter my room. It happened that there was no light near either door, and as there was but little difference in the keys it was very annoying at times to find after in- finite trouble that the wrong key had been _ inserted in the fugitive keyhole. To overcome this trouble I drilled a 3/16-in. hole in the upperside of the key tothe outside door, the side by which it was at- tached to the key ring. To Fai LARGE KEYsRING a LATCH=KEY book. Sent free upon request. THE L. 3. STARERETT COC. The World’s Greatest Toolmakers Mfrs. of Hack Saws Unexcelled ATHOL, MASS. THE BOY ELECTRICIAN Practical Plans of Electrical Apparatus for Work and Play with an Explanation of the Principles of Every-day Electricity. $2.60 Postpaid, POPULAR SCIENCE MONTHLY, 225 W. 39th St., New York THE MODEL T FORD CAR Its Construction, Operation and Repair, Including the Fordson Farm Tractor, F. A. Lighting and Starting System, Ford Motor Truck. Price $2.00 Postpaid. POPULAR SCIENCE MONTHLY, 225 W. 39th St., New York NEW MOTORS ee — C., 220 v. Gd-.,1750 R.P.M., Complete with hase and pulley. %0P. - $46.50 Tar. - $66.50 2uP. - $86.50 3uPp. $98.50 5p. $1650 Generalors sl table for all lighting. Battery Chargii ind Po ov. tou ---$19:50 1Sv.,10amp $26.50 40v,6amp.-- $31.50 Reo ee 110 or 220 volts, D. C., eee oP M. With bone pulley end starting box. 1/4 B.S. $28.50 Wf HP. tus tet $2850 Vaur. -- tue -- 2 aP. noo R rp tenatas UL ae. $28.50 V4 W218 ing $28.50 Va ian . $46.50 if Kismat $54.50 1 kere . $7450 2 Kramtinte $126.50 $58 50 - $82.50 - $124.50 Here is a way to arrange a bunch of keys so that the one you use the most will automatically pre- sent itself to your search- ing fingers whenever you pull your keys out of your pocket and the proper latch key automatically . the regular hole in this key I fastened the in- side door key by asmall link. Then I had but to take the bunch of keys from my pocket presented itself.—J. J. LANKEs. 110 v, 2% amp. $31.50 110 v, Samp. -- $52.50 40 v, 12 amp. -- $52.50 . 110 v, 9% amp. $67.50 40 v, 25 amp. -- $67.50 110v,18amp. $116.50 40v.,50amp. $116.50 110v,26amp. $156.50 110v,50amp. $238.50 A Bie Sup. -- $142-5C mitt $106.50 54P. - - $218.50 WRITE FOR CATALOG. BARGAINS IN MOTORS AND GENERATORS Ih SPECIAL 3 etigte- - 9146.50 gu: ‘WP. — $188.50 H.P.ic.o: SP. 1750 RPM, 4 cord, plug and SHIPPING TERMS: 22.2". MANUFACTURERS’ DISTRIBUTER Stews. $116.50 CHAS. H. JONNSTON, Box 44, West End, Pittsburgh, Pa. oll orders. ena with Bil of Ladiog ettached by tresght, . 131

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You are paying for these books even though you dont have them The difference between what you CAN EARN with their help and what you DO EARN now is the price you pay. With the money you ought to get but don’t, you pay for any set several times over. Every month you can earn enough extra to pay for the set you need. These books bring the expert advice and the most modern approved methods of the world’s greatest authorities right to your home. They explain everything you ought to know— they will fit you to get more money out of the work you are doing now —they will fit you to hold a better job—the job you want but have never been able to get. Read our FREE examination offer below, that brings the books to you without cost and guaran- tees your satisfaction. Pav-Raisin$ Books at Greatly Reduced Prices Acceuntancy and Business Management vols., 2700 pages, 1000 pictures. Was $250. Now $29.80 Caappetey and Contractin 5 volumes, q188 1000 pictures. Was $37.50.. 3 24.80 Civil Engineering. 9 volumes. 3900. a 3000 pictures. Was aa Yow 39.80 Electrical Engineering. 8 volumes, 4100 pages, pictures. Was Most sicaucacee Now 34.80 Automobile Engineering. 6 volumes, 2600 pages, 2000 pictures. Was $45.00........ Now 29.80 Machine Shep Practice. 6 volumes, 2300 pages, 2500 pictures. Was $45.00........ Now 29.80 Steam end Gas Engineering. 7 volumes, 3300 pages, 2500 pictures. Was Te Now 29.80 Law and Practice. (with reading course) 13 volumes, 6000 pages, illustrated. Was $97.50. Now 49.80 Fire Prevention and Insurance. 4 volumes, 1500 pages, 600 pictures. Was $30.00.....) Yow 19.80 be an, ye Lng omy 4 volumes, 1728 pages, 2 $30.00 pictures. access NOW 19.80 Sanitation, Heating and Ventilating, 4 vol., 1454 pages, 1400 pictures Was $30.......Now 18.80 Drawing, 4 volumes, 1578 pages, 1000 pitares, blueprints, etc. Was $30.00............. Now 19.80 Send No Money Shipped for 7 Days’ Trial Write the name of the books you want on the cou- pon and mail it today. We will send the books at once, express collect, and you can use them just as ifthey were: your own for a whole week. If you decide you don’t want to keep them, send them back at our expense. ‘Only 75 Cents a Week |- If you like the books, as thousands of other men ‘ have after examination, just send us.$2.80. You can \sehd the balance of the special! reduced price the same way—$3.00 each month: Start right now and fit yourself fora better job and bigger pay. The better job will be looking for you if you do. Be ready to meet it when it comes. SEND THE COUPON NOW. American Technical Society, Dept. X209, Chicago, U. S. A. American Technical Society, Dept. X209, Chicago, U.S.A. | Please send me set of for 7 DAYS’ examination, shipping charges col- | lect. I will examine the books t oroughly and, if satisfied, will send $2.80 within 7 days and $3 each month until I have paid the special price of | Ri. . vbsaede If I decide not to keep the books I will return them at your expense at the end of one week. | rrr ere eee eee eee eee ee ee eee ee ee ee Se nde renew ab ddiba 0 vets coagicsee (Please fill out all three lines.) eseee How and When to Cut Your Canary’s Claws F the cage of a canary is supplied with thin resting-sticks, the birds will often develop various infections of the foot. Such sticks do not give the bird a safe resting-place. They should be removed and replaced by larger, oval, not rounded, twigs which the bird cannot encircle with its claws. The claws often grow abnormally long and hooked, then the birds be- come entangled in the wire mesh of the cage and dothemselvesinjury. Splint- ered claws are also often met with; A canary’s claws must be manicured as well as your own finger-nails. Here is the right way to do it and keep your bird healthy these, when they break off close to the flesh, cause wounds and swellings. Other claws bend and grow backward so as to enter the flesh. This causes: infections. Under all these circum- stances the claws must be cut back. Take the bird in your left hand so that it lies on its back. Encircle the neck with thumb and_ forefinger. Gently lift the foot, being careful not to touch the nails. Hold against the light. Cut the nails with a sharp pair of shears where they are still opaque and just below the transparent section which is filled with blood. When held in such-a position the transparent section of the claw can be easily recognized. —ERNEST BADE. e-- | A Circular-Saw Attachment to Hasten Production STOCK authorization order called for about 1000 whitewood boards from 6 to 10 in. wide and about 2 ft. long, but only \% in. thick. These boards had to have a )-in. slot all the way around the edge and be about 4 in. deep. At first it was a problem, as many of the boards were green or warped, and many, as the slot was cut, had a ten- dency to curve a trifle and break off or cut through the remaining 1/16-in. side wall. Many times I nearly cut my finger until I devised a scheme to hold and feed the boards to the saw. A piece of %{-in. pine about 6 in. 132 Popular Science Monthly PAT ds i Th A Tf , SEND THIS a (A | DON’T LOSE YOUR RIGHTS TO PATENT PROTECTION Before disclosing your invention to anyone send for blank form **‘EVIDENCE OF CON- CEPTION”’ to be signed and witnessed. A sample form together with printed instructions will show youjust how to work up your evi- dence and establish thesame before filing ap- plicaticn for patent. As registered patent at- torneys we represent hundreds of inventors all over the United States and Canada in thead- vancement of inventions. Our schedule of fees willbe found reasonable. The form ‘‘Evidence of Conception,”’ sample, instructions relating to obtaining of patents and schedule of fees ones — request. Ask for them,—a post card will do 274 Ouray Bidg. WASHINGTON, D. C. Originators of forms ‘‘Evidence of Conception.” PATENTS Booklet Free Highest References Promptness Assured Best Results Send drawing or model for preliminary examination of Patent Office records : and report as to patentability All Business Given Prompt and Proper Attention WATSON E. COLEMAN, Patent Lawyer, 624 F St., Washington, D. C. Intensely evo: booklet free. Wonderful results. E. GYDE CO., Washington, D.C. Charge Batteries-Make Your Own Light po Bn on ae Tights for as as low pe at and —— the same charging batteries 2 of $10 *6 to month Hine shaft or SSS Small Payment Puts This Money-Maker in Your Garage or Shop Balance on easy terms. Profits pay fer out- fit. Absolute Money-Back Guarantee. Ask our ——— nt about pr oper s size for in this ad to your letterhead zeds write TODAY for information. Hobart Brothers Company, Box S-126, Trey, Ohio FOR THE INVENTOR About to take out a patent and planning to make it pay dividends we have a prospectus that will place inventions on a profitable footing. Send for your copy now. BAFF PATENT LAW OFFICE 311 Main Street, WORCESTER, MASS. GET BIG BUSH OFFER ’ ee County Onty four and De Laxe six. Don’t wait. Write today BUSH MOTOR O0.,Uihenge, taste, Bent.et: Bush Temple Damiilar Nmonree Manthl., ges 5 W =} as) ee ee ae ae a a Ud Or

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é e ; a i

December, 1920 wide and 12 in. long was cut at an angle of 45°. Slots about 6 in. deep and about )¥ in. apart were cut in the

; SLOTTED “La 4 GUARD | = -I<t + SAW DETAIL OF GROOVE

Rig up a fingered guide-board like this to protect your fingers from the circular saw end with the grain. This board was then clamped to the saw-table and the boards fed to the saw. These artificial fingers kept the board in-place and did a much quicker and easier job than I had ever been doing.—THERON -P. FOOTE. Electrifying the Ford Tail- and Dash-Lamps - N ingenious arrangement for elec- tric dash- and tail-lights, for which current is delivered from the magneto, is shown-in the illustration. It is important to use lamps of the correct voltage. Examine the head- light bulbs and use lamps of the same voltage for the dash- and tail-lights. Most Ford cars use 6-volt head-lamps, but in some of the later models 9-volt head-lamps are fitted to cooperate with the 18- volt magneto. If the correct lamps are used, there is very little danger of their burning out, as the

DASH SWITCH MAGNETO bu? TERMINAL vice DASH (CO LAMP 6v.2cRr : TAIL aes < GROUND on FRAME It is difficult to light the tail- and dash-lamps on a Ford. - Why not elec- trify them?

-sum of the resistance of the two lamps in series is high, and most of the current generated passes through the headlights, which have a lower resistance. Glass Drill Made from a Three-Cornered File DRILL for the purpose of drilling holes in plate or window glass is made in a very short time from an old three-cornered file. The file, which may be 4 in. long, or of any suitable size, is ground down on the flat surfaces on an emery-wheel so that it has a rounded head and a blunt point in the center. Be careful, when grinding the file, that .you do not burn it and there- by lose the temper. After it has been ground, sharpen the surfaces on an oilstone much as- you would the knife of .a plane, but giving the file an up-and-down motion at the same time you are giving it the. back-and-forth movement; so that the entire. surface is sharpened in one operation. Be sure

__ The ’ Sargent ‘Auto- Set Cuts True Cuts Fast SK any carpenter about the Sargent Auto-Set Bench Plane. Inquire about its cutting qualities and about its auto-set feature. He will tell you that it is a dependable tool with a big _ time-saving improvement in the self-adjusting sets. The cap and clamp of the Sargent Auto-Set Bench Plane are fitted together as one piece, with a set screw to regulate

Sargent Cylinder Day and Night Latch Put it on doors—inside and outside, front and back—that you want securely barred. An ordinary mortise lock is “easy pickings,” but a cylinder latch keeps the intruder outside. “Press the button” to dead lock the bolt or hold it back, as de- sired. “Pull the button” to re- lease the bolt. Self-locking— closing thedoorsprings the latch.

55 Water Street the position. Another set screw ad- justs the cutter. May be taken down for whetting in a few seconds and assembled as quickly. Cutter and cap go back ex- actly in the same position as before. Made in six sizes: smooth or corrugated bottom; fore, jack, smooth or jointer patterns. Send for descriptive booklet, SARGENT & COMPANY Hardware Manufacturers New Haven, Conn.

SARGENT

LOCKS AND HARDWARE

High Frequency y, Anpersts, Its Construction and Practical Application By Thomas Stanley Curtis. The most comprehensive and thorough work on this interesting subject ever produced. 1920 edition—275 pp,—Price, $3.00 postpaid. Popular Science Monthly 225 West 39th Street, New York Shop Practice for Home Mechanics By Raymond Francis Yates. The book Ay nothing that wall Be of use to these whe use tents ¢ to tiose who wish to learn the use of t 314 pp —309 illus. Price, $3.00 postpaid. Popular Science Monthly 225 West 39th Street, New York

Page 118

You are paying. for these books even though you dont have them The difference between what you CAN EARN with their help and what you DO EARN now is the price you pay. ith the money you ought to get but don’t, you pay for any set several times.over. Every month you can earn enough extra to pay for the set you need. These books bring the expert advice and the most modern approved methods of the world’s greatest authorities right to your home. They explain everything you ought to know— they will fit you to get more money out of the work you are doing now —they will fit you to hold a better job-—the job you want but have never been able to get. Read our FREE examination offer below, that brings the books to you without cost and guaran- tees your satisfaction. Pay-Raisiné Books at Greatly Reduced Prices Acceuntancy and Business Management vols., 2700 pages, 1000 pictures. Was $52.50. Now $29.80 Capone ton at Contractia 5 volumes, 2138 pictures. Was $37.50.........Now 24.80 Civil Eaginesr in 9 volumes. 3900 es, 3000 7.50 ON pictures. Was $67.50.............. Now 39.80 Electrical Eadinseria 8 volumes, 4100 pages, 3300,pictures. as $50.00 OO. csc scsccacs OW 34:80 Automobile Raginecring 6 volumes, gece pages, 2000 pictures. Was $45.00........} 29.80 —— Shop Practice. 6 volumes, nen 2500 pictures. Was $45.00........Now 29.80 Steam end Gas Engineering. 7 volumes, 3300 pages, 2500 pictures. Was a aa. Now 29.80 Law and Practice. (with reading course) 13 volumes, 6000 pages, illustrated. Was $97.50. Now 49.80 Fire Prevention and Insurance. 4 volumes, pages, 600 pictures. Was $30.00.....) Yow 19.80 we > Ay ® Tebetreghy 4 volumes, 1728 pages, pictures. ere Now 19.80 Sanitation, Heating and Yontttocing, 4 vol., pages, 1400 pictures as $30.......Now 18.80 Drawin at. 4 youmes. 1578 pages, 1000 eaneees. blueprints, etc. PED Sa ccccnencciied 19.80 Send No Money Shipped for 7 Days’ Trial Write the name of the books you want on the cou- pon and mail it today. . We will send the books at once, express collect, and you can use them just as if they were your own for a whole week. If you decide you don’t want to keep them, send them back at our expense. ‘Only .75.Cents a Week | If you like the books, as thousands of other men ‘ have after examination, just send us.$2.80. You can |sehd the balance of the special reduced price the same way—$3.00 each month: Start right now and fit yourself fora better job and bigger pay. The better job will be looking for you if you do. Be ready to meet it when it comes. SEND THE COUPON NOW. American Technical Society, Dept. X209, Chicago, U. S. A. rican Technical Society, Dept. X202, Chicago, US.A. | American Technical Society, Dept. X209, Chicago, U.S. | PD MIE. ok 655 Soc es cnwwn wens for 7 DAYS’ examination, shipping charges : col- | lect. I will examine the books t oroughly ‘nd, = satisfied, will send $2.80 within 7 days an i month until I have paid the special i ny ot | A Pree If I decide not to keep the books I will- | return them at your expense at the end of one week. | ce (Please fill out all three lines.) How and When to Cut Your Canary’s Claws F the cage of a canary is supplied with thin resting-sticks, the birds will often develop various infections of the foot. Such sticks do not give the bird a safe resting-place. They should be removed and replaced by larger, oval, not rounded, twigs which the bird cannot encircle with its claws. The claws often grow abnormally long and hooked, then the birds be- come entangled in the wire mesh of the cage and dothemselvesinjury. Splint- ered claws are also often met with; A canary’s claws must be manicured as well as your own finger-nails. Here is the right way to do it and keep your bird healthy these, when they break off close to the flesh, cause wounds and swellings. Other claws bend and grow backward so as to enter the flesh. This causes: infections. Under all these circum- stances the claws must be cut back. Take the bird in your left hand so that it lies on its back. Encircle the neck with thumb and_ forefinger. Gently lift the foot, being careful not to touch the nails. Hold against the light. Cut the nails with a sharp pair of shears where they are still opaque and just below the transparent section which is filled with blood. When held in such-a position the transparent section of the claw can be easily recognized. —ERNEST BADE. e-- ide Civcular-Saw Attachment to Hasten Production STOCK authorization order called for about 1000 whitewood boards from 6 to 10 in. wide and about 2 ft. long, but only % in. thick. These boards had to have a 1%-in. slot all the way around the edge and be about 14 in. deep. At first it was a problem, as many of the boards were green or warped, and many, as the slot was cut, had a ten- dency to curve a trifle and break off or cut through the remaining 1/16-in. side wall. Many times I nearly cut my finger until I devised a scheme to hold and feed the boards to the saw. A piece of 34-in. pine about 6 in. 132 Popular Science Monthly PAT NTS U.S. 4 | DFOR . LU ! SEN THIS FORM DON’T LOSE YOUR RIGHTS TO PATENT PROTECTION Before disclosing your invention to anyone send for blank form *‘EVIDENCE OF CON- CEPTION”’ to be signed and witnessed. A sample form together with printed instructions will show youjust how to work up your evi- dence and establish thesame before filing ap- plicaticn for patent. As registered patent at- ‘ torneys we represent hundreds of inventors all over the United States and Canada in the ad- vancement of inventions. Our schedule of fees willbe found reasonable. The form ‘Evidence of Conception,”’ sample, instructions relating to obtaining of patents and schedule of fees ont aoe request. Ask for them,—a post card will do PATENTS ANDO 274 Ouray Bidg. WASHINGTON, D. C. Originators of forms ‘‘Evidence of Conception.” PATENTS Booklet Free Highest References Promptness Assured Best Results Send drawing or model for preliminary examination of Patent Office records and report as to patentability All Business Given Prompt and Proper Attention WATSON E. COLEMAN, Patent Lawyer, 624 F St., Washington, D. C. Intensely interesting booklet free. Wonderful results. E. GYDE CO., Washington, D.C. Charge Batteries---Make Your Own Light Tag Listing ond Date Cheon, oa Of $100 to ee Operat: month Fine-shaft or =. Balance on easy terms. Profits pay for out- fit. Absolute vent sb Guarantee. A our Service Tope it about proper size for your needs. ie of to your letterhead aed write TODAY '! a information. Brothers Company, Box S-126, Troy, Ohio FOR THE INVENTOR About to take out a patent and planning to make it pay dividends we have a prospectus that will place inventions on a profitable footing. Send for your copy now. BAFF PATENT LAW OFFICE 311 Main Street, WORCESTER, MASS. GET BIG BUSH ere f ‘e wait! as spare. time ‘ean \ make ° Feirojusee, oat County Onty antec. Bush fight four and De Luxe six. Don’t wait. Write today! BUSH MOTOR CO., Chicago, Ulinois, Dept.si11 Bush Temple ene ICN et oe mK NO et a4 2 ™ Ss tO hae oO - a ae ee ree) PR oD m= ct Se kL -¥y te my Ot et 85 oR CF

Page 119

SL he RCN CIS SALE NEES DROIT

December, 1920 wide and 12 in. long was cut at an angle of 45°. and about )% in. apart were cut in the

" SLOTTED ~~ 3 r) GUARD | oo -it -—SAW DETAIL OF GROOVE Slots about 6 in. deep |.

‘Rig up a fingered guide-board like this to protect your fingers from the circular saw end with the grain. This board was then clamped to the saw-table and the boards fed to the saw. These artificial fingers kept the board in place and did a much quicker and easier job than I had ever been doing.—THERON -P. FOOTE. Electrifying the Ford Tail- and Dash-Lamps - N ingenious arrangement for elec- tric dash- and tail-lights, for which current is delivered from the magneto, is shown in the illustration. It is important to use lamps of the correct voltage. Examine the head- light bulbs and use lamps of the same voltage for the dash- and tail-lights. Most Ford cars use 6-volt head-lamps, hut in some of the later models 9-volt head-lamps are fitted to cooperate

DASH SWITCH MAGNETO

with the 18- TERMINAL volt magneto. 38) - If the correct TAL LAMP lamps are used, there is very little danger of their burning out, as the

It is difficult to light the tail- and dash-lamps on a Ford. - Why not elec- trify them? -sum of the resistance of the two lamps in series is high, and most of the current generated passes through the headlights, which have a lower resistance. Glass Drill Made from a Three-Cornered File DRILL for the purpose of drilling holes in plate or window glass is made in a very short time from an old three-cornered file. The file, which may be 4 in. long, or of any suitable size, is ground down on the flat surfaces on an emery-wheel so that it has a rounded head and a blunt point in the center. Be careful, when grinding ‘the file, that you do not burn it and there- by lose the temper. After it has been ground, sharpen the surfaces on an oilstone much as. you would the knife of a plane, but giving the file an up-and-down motion at the same time you are giving it the back-and-forth movement; so that the entire. surface is sharpened in one operation. Besure

. The ‘Sargent Auto- Set Cuts True Cuts Fast SK any carpenter about the Sargent Auto-Set Bench Plane. Inquire about its cutting qualities and about its auto-set feature. He will tell you that it is a dependable tool with a big _ time-saving improvement in the self-adjusting sets. The cap and clamp of the Sargent Auto-Set Bench Plane are fitted together as one piece, with a set screw to regulate

Sargent Cylinder Day and Night Latch Put it on doors—inside and outside, front and back—that you ‘vent securely barred. An ordinary murtise lock is “easy pickings,” but a cylinder latch keeps the intruder outside. “Press the button” to dead lock the bolt or hold it back, as de- sired. “Pull the button” to re- lease the bolt. Self-locking— closing thedoorspringsthelatch.

patterns. 55 Water Street the position. Another set screw ad- justs the cutter. May be taken down for whetting in a few seconds and assembled as quickly. Cutter and cap go back ex- actly in the same position as before. Made in six sizes: smooth or corrugated bottom; fore, jack, smooth or jointer Send for descriptive booklet, SARGENT & COMPANY Hardware Manufacturers New Haven, Conn.

SV Nim

LOCKS AND. _ HARDWARE

High Frequency Apparatus, Its Construction and Practical Application By Thomas Stanley Curtis. The most comprehensive and thorough work on this interesting subject ever produced. 1920 edition—275 pp,—Price, $3.00 postpaid. Popular Science Monthly 225 West 39th Street, New York Shop Practice for Home Mechanics By Raymond Francis Yates. The book omits nothing that will be of use to those who use tools or to those who wish to learn the use of tools. 314 pp —309 illus. Price, $3.00 postpaid. Popular Science Monthly 225 West 39th Street, New York

toil sie so aheeeiice E ENGINE “eae Potion rag Saw +

prices on all ofa Heh nals Write for ts um ith Beeiaicdten tae Magnete . a ecess. erose Ps hn te Y " Touest priced H, 4 Ignith ion Engine 4 Sold Bold Direct-Bi z Saving--Cuick § Service. ue Page “WITTE ‘ENGINE WORKS

ere

Page 120

Try This \Ried Devil een i1¢ oT nee Wrench Set on the most stubborn nuts —and you’ll agree that it’s made to stand up under the hardest usage. Made of open hearth steel, heat-treated for strength. Denil REG.U.S.PAT. OFF. Mechanic’s Wrench Set Recommended for auto- mobile, gas engine or me- chanical repair work of any kind. There’s a size wrench that will tackle any size nut up to 1’. Every tool guaranteed. Five wrenches in a set— each set, in a neat khaki ‘case that can be rolled up and put in the coat pocket or the tool kit. At all dealers, or if not, send $1.00 for ““Red Devil” Wrench Set No. 91. Send for Tool Booklet. Smith & Hemenway Co., Inc. 264 Broadway New York, N. Y. Manufacturers of Pliers, Glass Cutters, Chain — Hack Saw Blades and Frames, Auger "Screw Drivers, Cold Chisels, Neil ullers, Lock Washers, etc. to have the three edges and the point sharp before attempting to drill a hole. Place the drill in the brace and moisten the surface of the glass that is to be drilled, with a little kerosene or tur- pentine. The author has found tur- pentine to give the best results. Always keep the drill wet with turpentine or kerosene to avoid chip- ping of the glass. Drill the hole half way through the glass and then com- mence on the opposite side. This will overcome chipping and cracking if you are to go entirely through the glass. Sharpen the drill frequently.—PAUL J. KORDEs. A Flexible Pipe Made - of Inner Tube FLEXIBLE tube or hose for con- ducting water can be made of an inner tube with the aid of a piece of spring wire wound into a spiral. Wind the wire about a spindle a trifle larger than the inside of the | tube. It should take the form of a large spiral spring. Then force it into the inner tube by screwing exactly as you INNCR TUBE Such a pipe can be used for conduct- ‘ing water or air where very little pressure is generated. If much pres- sure is exerted in the pipe, it can be kept from expanding by winding a second coil outside. By wrapping the outside with tire tape, the same strengthening effect can be produced. SPIRAL SPRING Here the inner tube is transformed into a flexible pipe with a piece of spring wire The Most Efficient Part of an Automobile HERE are hundreds of moving parts on an automobile or motor- truck, but none works so hard and so efficiently as a universal joint. Sucha joint is necessary on the propeller shaft extending from the clutch to transmission and from the transmission | to the rear axle, as the case may be. Universal joints are known to operate ‘at over 98 per cent efficiency, which cannot be said of any other part of an automobile doing such strenuous work. The universal joint, as its name indicates, allows for free or universal movement of the propeller shaft. It is like your thumb which you can wiggle in all directions. A universal joint takes the power of the engine and transmits it to the propeller shaft, and at the same time this joint may be constantly moving, first in one direc- tion, then another, but usually it moves up and down because the rear axle keeps moving up and down over the road. The propeller-shaft angu- larity varies according to the relative movement of the rear axle, and were it not for the use of universal joints, the 134 would a screw. |, = ; t ) end tore articles Popular Science Monthly Our Catalog has fostrated pages of Diemond Row Gialog hae Pine » Diamond Ear Screws, Bian nd Scarf Pins Watches, Wrist Watches, Brace- Brooches, Bar Pins, Chains, Pearl Beads, Silver- oaderfally showy assembled Solitaire ware; also our wonde Diamond Clusters, select will rename all shipping Prepaid, "Vou eee and exam: ine the article in your own hands. Di d Rin For Christmas ings Sent Cased in Handsome Ring Bor, Ready for Presentation wild iy, ull, wy wre, °c taires and Cluste ters, latest est. popular plata plain taires jus’ Rings, and fancy engraved m mmogutings The G Yellow se reen or Bat God. weer aot ion, see Catalog. Priced at $85, $125, $150, $200, $250 4x } CREDIT TERMS 2o2zri=i ox ory, d pA talog, tak gelestions, and and have as many To the Gash & ayers, While our prices aro lower than the cash prices ons of other co. we make a discount of eight Seecen ss for r cash in fu fuil fa. advance 4 or on delivery. is Accepted. LOFTIS BROS. & CO. THE NATI NAL CRE EWELERS Dept. G-871. 3 Seeoy hd Y: Ses iLt, STORES 1 IN LEADING. CITIES oo= oe Ss — BUYS A us " Mandolin, ( Gultar-Banjo, Mandola, Mandolin-Banjo, Mando-Cello, Harp-Guitar, ee & Entertain Your Friends r Gibson now. ¥% la, wie of the Su tine Gay. me pb irjende willbe surprised and vin > about Wm. Place, Jr. fswe: Bes ee oie Bskcet ih ieiseant {fener Bante fh ot y" Gibson Mandolin- ae Guitar Co., 0 Mandolin-Banjo [) Cals Banke ‘¢ 492 Parsons St, Name Kalamazoo, 1 Aad + Mich, U.S.As sure you have checked instrument. ~ “ - oe ; : | t Oo, >TO bh AM 2 me: S® eee,

Page 121

December, 1920 shaft would -bend.or break and hence could not transmit power. It is remarkable how this part stands up even when owners forget it. Most ! owners do not know wiat..a universal joint looks like because it never gives any trouble, but the wise owner will not allow joints to go without grease. Grease is easily injected through the - filler opening by means of a suitable grease-gun. The joint should not be filled completely—one third full is sufficient.—H. A. TARANTOUS.

- Repairing a Broken Lug with a Washer N emergency repair for a lug broken in tightening up an outlet water connection for an automobile, is shown in the accompanying illustra- tion. These connections are usually cast iron, and in putting in the bolts an A washer in- serted over a broken bolt-hole on a lug will enable you to run the car until the broken part is replaced

\ i BREAK IN FLANGE extra twist will frequently crack them. The repair was made simply by inserting a large washer under the ‘boit-head when the gasket was in ‘place;- and screwing down solidly. ‘This repair will carry over until a ‘suitable replacement part can be obtained.—GEorGE L. LUERs. How to Make a Double Center Punch HE writer: had a lot of machine pieces given him to center punch. The holes were all the same distance apart, so to save laying them all out, and probably. making them inaccurate- ly, he invented the: double punch shown in theillustration. With it, all that Was necessary was to lay out the first hole on the piece of $"D1AM

. Beat the Coal Shortage with the OTTAWA

Cords a Day!

Ap 310 Saw , R Does pag of DB, Gutsa- t y fl ~ 10 to —— / minute nea Used by the U. 8. Newly Invented bbe Government Clutch j aon —— Schools — - an = Stops — IY Saw Engine uns On — £4 Wife

hk Pat. Applied For Plenty of Fuel For Yourself and to Sell At High Prices! Log Saw and make big money. Cut your entire winter’s fuel supply quick, then make big profits saw- ing wood for others and selling wood in nearby towns. Provides cheapest and most plentiful fuel at a cost of about 1144c a cord. Do the work of 10 to 15 able- bodied men at one-tenth the cost with the OTTAWA [OG SAW Cuts Down Trees—Saws Logs By Power Pulls Over 4 H-P. Makes 310 saw cuts a minute. Direct gear drives saw—no chains to tighten; no keys; no set screws. 4-Cycle Frost Proof Engine with counter balanced crank shaft. Oscillating Magneto Ignition, no batteries ever needed, and Automatic Governor with Speed Regulator. Uses little fuel, Easy to operate. As easily moved by one manas a wheelbarrow. When not sawing, engine runs pumps, feed grinders, etc. 30 DaysTrial.Every Cash or Easy Terms. Get our OTTAWA shipped on 30 = payment plans of purchase and _ find days trial. Must fulfill out how easy it isto own an OTTAWA 10-year Ottawa Guaran- Log Saw. It will soon pay for itself. tee. For nearly 20 years Any man with logs tocut can not afford we have been selling to be without this Log Saw, and he can direct from factory to soon own it under our wonderful sell- users, saving them thou- ing plan. sands of dollars. Now over 10,000 satisfied fFpee Book! Send your name and address users all over the world. Special Offer. Use oncoupon below so that the coupon and send at —_—you will receive full de- once for Special Offer tails on Special Offer 1921 and Low Direct Factory Improved OTTAWA Log Price. Don’t delay. It Saw. ole. cur Sue ai costs nothing to inves- page book. Shows how thousands of OTTAWA

tigate. Just send your name and address on the

f lete in- users have paid for @gae2 eae : my stat tg ane pel their log saws in a or f MAI L TH is (8), | ' introductory offer. few weeks. Ottawa Mfg. Co. yg 1803 Wood St., Ottawa, Kansas, Please send me Special Offer and a Free Book on the Ottawa Log Saw. 4 OTTAWA MFG. COMPANY 1803 Wood St., Ottawa, Kansas. Address. .,.+++ CHO COSCO CRO CCC COC C ECCS a —pRanumunaenasancacal

—- metal. Setting iS ue | the punch in ie AC $ /4 hole No. 1, a pe The two points of this blow wasstruck center punch make éven which made spacing of a row of holes at No. 1 punch marks possible and 2. The punch was then set in No. 2 hole and another blow struck which made No. 3 hole the correct distance away from No. 2. The procedure was repeated until all the holes were made. Con- siderable time was saved by adopting this scheme. This double center punch will be found advantageous when it is nec- essary to make evenly spaced punch- marks for drilling rivet-holes in boiler- plate.—J. W. MOORE.

| ARMATURE WINDING. By Davip P. Moreton. This book covers the theory of armature winding and the prac- tical application of these principles to the winding of various types of armatures. The book is profuse'y illustrated with wiring diagrams and photographs of coil winding apparatus and is a thoroughly modern treatment of the subject. rice, $2.60, postpaid. Book Dept. Popular Science Monthly 5 West 39th Street, New York ntry and Mechanics for Boys An excellent gift for the boy who likes to make things. Directions for making playground and camp equipment, models, mechanical and electrical toys and gifts, etc. Price, $2.65, postpaid Popular Science Monthly 225 West 39th Street New York Wireless Taught By Mail - "4

. SC) rare Se OPERATORS NEEDED NOW — GOOD PAY — RAPID PROMOTION Men and boys needed for Merchant Marine, Big Land Wireless Stations, Railroad and Telegraph Companies, Commercial Concerns, and Lake and Ocean Steaimships. Salaries to start $125 a month plus-Room, Board, and Laundry, which means a total of $200 or —o— SN more a month. One of our recent graduates is getting $6000 a ‘year. Chance to see the world or locate in land station in America: COMPLETE COURSE BY MAIL. Some of our students have actu- ally passed the commercia! examinations in ten weeks. One student secured his license in eight weeks. Start studying NOW in spare \ time at home. We furnish FREE to every student, an automatic transmitter and receiver, which sends vou messages just as you would receive them from a distant station. You receive this instrument after your enioliment; it becomes your personal roperty upon completion of our course. Write today for FREE BOOK of particulars. | feet) NATIONAL RADIO INSTITUTE, Dept 390, Washington, D. C. SS “0s _ ~

4 » -

EE SI ES

Page 122

Check Up the Human Factor Your machine is human in the manner that it depends on human skill and ibection to get the production that is in it. Though the quality of its con- struction be the best, the quantity of its production varies with the skill and industry of its operator. This. efficiency of the human factor is what you want to check up with a COUNTER —for it decides whether. you’re © gétting out of your machine a full return for the money and brains put into it. Fhe small Revolution Counter below registers one for a revolution of a shaft, recording a machine operation, or product. Though small, this counter is very durable; its mechanism will stand a very high rate e making i especially suituble for light, fast- ning machines, and most adaptable to experimental work. If run backward, the counter sub- tracts. Price $2.00. (Cut nearly full size.) The Set-Back Rotary Ratchet Coun- ter below is for the larger machines, such as punch presses and metal-stamping machines, where a reciprocating movement . indicates an operation.

Registers one for each throw of the lever, and sets back to zero from any figure by turning knob once round. Supplied with from four to ten figure-wheels, as required. Price with four figures, as illustrated, $11.50—subject to discount. (Cut less than %4 size.) There’s a Veeder exactly suit- able for the type of machine you’re interested in; write for new illustrated booklet. The Veeder Mfg. Co., 44 Sargeant St., Hartford, Conn. When the Wind-Shield Rubber Wears Off HEN the rubber on the wind- shield wears off or is lost, you will find it very convenient to replace it with a piece of rubber tubing about 3in.in diameter with as heavy a wall as you can purchase. As shown in the il- lustration, it will be necessary to by over 96 manu- facturers. Eusy to 1, simple to operate, no maintenance cost. Guaranteed for 10 years. In eingie Tone and Chime. Ask your dealer or write BUELL MFG. CO. Cottage Grove at 30th, - - Chicago Pilliod TOOL CASES EXCEL Machinists, Tool Makers and Cafpenters find them most satisfactory in construction, appearance, service and price.

Booklet describing 20 styles _ on request. The Pilliod Lumber Co. Dept. A, Swanton, Ohio

Power Benders THREE NEw M MODELS chines {pat} sloctrtcally, oper= elec ated t zis from 1 inch tod inted ont = We Ly 6 wk ‘acture TEN other sizes, hand operated to bend from 1-8 to 6 inches. American Pipe

Manufacturers—51 Pearl Street, BOSTON, Mass, U. S. A. 9 CORDS IN 10 wo

BY ONE MAN. iets Ems! - THE WOODE, Saves money and backache. Send for K catalog No. B138 showing low

rice and latest aed rma First order gets agency. Feiding Sawing Machize Co.. 161 West Harrison St Chicago, Ui The Midget Slide Rule wall ai divide ~ ty 5 pumbers, ~w Cleartone Phonographs 954-00 to $200.00 Retail Our Sundry Dept. offers Needles 38c per thou thousand. Motors S13 35 to "sigite once ich. a topes Be Gos edch.” Recorde, ‘Needics, ain sprin fs nable prices

Write r 84- catalogue, the only one of its kind in “America, iHustrating 33 different styles of Telking. M chines ‘and over 600 different Phono- graphic Parts. "LUCKY 13 PHONOGRAPH COMPANY

Export Dept. 503G, East 19th Street, New York

more Perhaps

Page 123

Sa ae RAN \ December, 1920 i i H ‘ ' scraped through the other. The pipe connected to. the vacuum hose carried | away the loose carbon as fast as it was ‘removed with the scraper. I found that this method enabled ’ me to do the work much more rapidly. ‘It has a second advantage in that it - leaves the combustion chamber ab- . solutely clean, and there is no danger ‘of leaving a deposit of carbon or dirt . . ! to score the cylinders.—F. G. J. To Evenly Space and Ink Lines in a Hurry HERE the mechanical drafts- man has been given a job which ' necessitates ruling many evenly spaced ‘ ‘jines in a hurry, the little cardboard ORAWING-BOARD T-SQUARE _. Alittle cardboard pointer attached to the T-square will enable you to draw evenly spaced lines quickly attachment shown in the illustration will be found to expedite the work. ._ First. cut a piece of ‘cardboard the .. Shape shown and attach it to the end of . THREADED IRON ROD TUBE “the T-square with thumbtacks. By: ‘setting the pointer against the line already drawn and moving it down. after each line is drawn, the lines will be found to be perfectly spaced. Adjustable Centers for Small Lathe-Work HE most difficult thing to finish in the lathe is a tube. To do the work right, a mandrel should be fitted, but this takes time and the mandrel costs more than the job is worth in the end. ‘The writer has found that it. pays to keep a goodly supply of thread- LATHEDOG % NUT Seana TrIREAD SPOOL END 2, This shows the jig with the spool ends with a tube in place spools on hand. The ends of these spools are cut taper, and by sawing off the ends and slipping them over a round iron rod, an adjustable arbor or mandrel is obtained which can be used for tubing from 1% to 1 in. in diameter. The holes are always cen- tered with the taper and the tube finds its own center as soon:as it is clamped into place. ; BRICK TROWEI DISSTON SAWS AND TOOLS Every Home Needs Some of These Tools Good. tools— Disston Tools—for eyery job around the house. Tools of Disston-Made Steel hardened and tempered for the particular use of the individual tool. Tools that do all the. work, they should instead of demanding un- necessary effort to offset their short- comings. Tools that expert artisans use — hence the best for the average house- holder. Sold by good dealers everywhere. Write for full information. HENRY DISSTON & SONS, Inc. General Offices: Philadelphia, U. S. A.

Page 124

—_ for new catalog our ertor Sedat Sheer inists — ae es Seeeuses WRENCHES, LATHE DOGS, CLAMPS , TOOL HOLDERS, FILES, CALIPER GAUGES- J-H-WILLIAMS SCO. TRICHARDS ST- BROOKLYN -N-Y. 7VULCAN ST: BUFFALO -N-Y:- 1007 W-120ST- CHICAGO - ILL:

- The Best Way to Drill a Triangular Hole AN you drill a hole larger at the bottom than at the top? In answer to this question we say ‘‘ Yes,” provided you use the ingenious device illustrated here. The shank of the tool has a slot cut in it to which is at- tached a slanting blade. This blade is about ¥\% in. thick and is pivoted with a pin to the shank of the tool. You can swivel this cutter, or blade, to any desired angle you wish, then having ob- tained the de- sired angle, you fasten the cutter in its correct position by the set screw.—J. W. MOORE.

Cutting a hole larger at the bottom than at the top sounds -impossible Here is the way it is done Increasing the Usefulness of a Wagon Wrench EFORE the advent of the auto- mobile this type of wrench was very common. It fitted two sizes of nuts, and there its use ended. I an that a few cuts of a hack- saw will extend its sphere of use- fulness. Two sections are cut out of the end, as in Fig. 1. One can be cut a trifle smaller than the other, in which case small nuts of two sizes can be

ioned in this way it can also be used to turn a How ‘the old wagon T-headed valve wrench can be brought key. — up to date again When pivoted upon a stout nail it will act as an emergency wire stretcher. It can be used as well for making a uniform kink in wire, so as to take up the slack.—_ JAMES M. KANE. A Copying Idea for the Photographer AVING a 5-by-7 camera and desiring to make full-sized copies of a batch of old 5-by-7 prints, nothing seemed . easier .than.to set. up and shoot. But right°then my troubles ‘started—the “camera -was fitted with -- 138

Popular Science- Monthly

Electricians’ Knife and Tweezers We can meet dealers’ demands at once and offer attractive quantity prices Write for description MATHIAS KLEIN & SONS, Mfrs. CANAL STA. 3, CHICAGO

handled. Fash- |.

Deafness Perfect hearing is now being re- stored in every condition of deaf- ness or defective hearing — causes such as Catarrhal Deaf. ness, Relaxed or Sunken Drum Thickened Drums, Roaring an <: Hissing Sounds, _ Perforat Ee Wholly or Partially Destroy eS oY; Drums Discharge from Ears, etc. Wilson Common-Sense Ear Drums “Little Wireless Phones for the Ears’? require no medicine but effectively replace what is lacking or defective in thenatural eardrums, They are simple Serica, Seren the wearer easily fits into the ears where ey areinvisible. Soft, safe and comfortable. Write today for our 168 page : FREE book on DEAF- giving you full particulars and testimonials. WILSON EAR = CO., Inc ted * 247 Inter-Southern ‘Louis KY. ASBESTOS We are miners and shippers of Crude Asbestos in any quantity. We produce all grades at our world famous BELL ASBESTOS MINES, in Canada. We also card fibres, spin yarns, weave cloths, and make all sorts of Asbestos products. For anything you want in Asbestos, turn to KEASBEY & MATTISON COMPANY Dept. S-4. AMBLER, PENNA., U. S. A. Owners of the world’s largest Asbestos Mines USE HB MOTORS FR, Sturdy Boll Bearing Elect Meee —Amole capacity, smooth-running and eco- uire little or no attention nder absolute money- back 2 One oe. Cash payme plan your staila on. Simply “state machinery you h re operate, current avilable, etc.

Ask for Tnformation on HB battery Gpansers. lighting cote ang nerators. oday fo rmation. HOBART BROTHERS CO Box S125, Troy, Ohio Make °80t0°300 Weekly

Selling Eagle Sawing Machines Every timber owner needs on’. Powerful, fast- cutting, one-man, log saw. A demonstration sells it. Representatives making big money every- where, Exclusive territory free, You can make $2.00 An Hour sawing wood curiae demonstra- tions. Write T: for fall — formation and_our special lo agent’s prices. Big opportunity. Eagle Sawing Machine Co., Dept. 481 Kansas City, Mo. GERSTNER TOOL CASES are attractive, compact, practi- cal; will serve exactly the use for which you buy a Case—to have greets. convenient viace for your Tools. Absolate satixfaction guaranteed. Catalor showing 30 Styles Yand sizes, free H. Gerstner & Sons ‘1000 Columbia Street Dayton Ohio

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December, 1920 a lens of 8%-in. focal length, while the bellows extension was only 12 in. Now, it is one of the fundamentals of photography that, in order to obtain a full-sized image of an object, the lens must be placed twice its focal length from the plate. As twice 814 is 17, I was some 5 in. on the minus side. For a while it looked as if I would have to be. satisfied with smaller -eopies or else build a 5-in. extension on my lens mount, when the great idea broke and saved the day. I bor- rowed a lens of 534, mounted it on a spare lens board, and the rest was mere routine work. s While the 534-in. lens would not: have covered a 5-by-7 plate at the ordinary extensions used in land- seape work, it gave even illumination. to the corners (and probably be- yond) when drawn out to a distance of 114% in.—FRANCIS M. WESTON, JR. A Way to Remove Stubborn Nuts Quickly HEN a nut becomes rusted, it is a very difficult job getting it off the bolt or stud on which it is set. To use a hammer and chisel usually results in the nut being made worthless. Being up against such a proposition and wishing to save the nut, which ‘was a special thread, we made a novel WRENCH HOLE A few blows with a hammer on this type of wrench will remove the most stubborn nut wrench as shown in the illustration. The hexagonal part of the wrench was set over the nut and a few good blows with a hammer given it. Off came the nut. So good was this idea that we _ adopted this style wrench for all such ’ jobs.—J. W. Moore. ' How Street Curbing Injures the Tires HERE is one bit of carelessness of which nearly all motorists are guilty at times, and which, unfortu- nately, is almost a habit with many. That is the practice of driving the tires against street curbs—most commonly in backing the car—so that the side walls and the fabric are bent. It pays to avoid these little bumps carefully as one of them may easily weaken the fabric to such an extent that a blow-out will result. Don’t park the car so that the front wheel is snugly jammed against the curb, because when you are ready to leave you may find it impossible to rexelesd ARE PRATT Amateur Bench Lathe No. 125 For a Variety of Work ORK out your ideas on this practical little lathe. It will handle a wide range of work. In fact, with its many possible attachments it gives you almost a complete shop in your own home or laboratory. It will take work up to 12 inches in length, with a swing of 7 inches. It is furnished with an adjustable Tee Rest, a Slotted Face Plate, a Saw: Arbor and a Drill Chuck of 0 to -inch capacity, with a No. 1 Morse Taper Shank. The Tail Stock has both lever and screw feeds. This useful machine has all the good features which characterize the Goodell-Pratt line of 1500 different tools. The same skillful workmanship, the same care- ful selection of materials, the same simplicity, utility and sturdiness are just as evident in this lathe as they are in any other Goodell- Pratt Tool. Let your dealer demon- strate what a serviceable machine this lathe is. And don’t delay writing for a more complete description. Complete pocket catalog sent on request. GOODELL-PRATT COMPANY

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What dors BROWN é&& Geuenstet= he want for Chiiehmas , Low is the time to be thinking of those little gifts which make Christmas a day of gladness ayd good-will. For ausetul gift to the mechanic or the techy for the holidays what could be nore appropriate thar) a good toal? Your dealer carrivs Brown & Sharpe Gols. Sisk to see the line of WMicroneter Calipers i ~ ca Gift Cases . Note the in finish and remember that seventy years experience quarantees | {ein accuracy, If your dealer cannot supply you, we'll be glad to send Catalog No,28 SH: APE ie os ae ric = ival student hone R. How to ke and Use it POPULAR ——— tase hich 225 West 39th Street ate: oy Frequency Apparatus, a By THOMAS STANLEY CURTIS, 69 pp., illus. Price, 50 cents. New York — > Every Monarch Lathe is a standard, the same quality construction is found throughout the Monarch Factory pro- month and one year. Each year there are pur- Lathes than there are lathes: built by any other high grade manufacturer. Write for-Catalog. The Monarch Machine Tool Co. 108 Oak Street Sidney, Ohio duction of one day, one [> chased more Monarch a electrical, rope, air- plane, piano, pipe- organ, flat, hoops, bale-ties, tacks, nails, barbed-wire, concrete re - inforce- ment. springs, net- ting, wire fences, steel posts, trolley-road wires, and rail bonds, wire wheels, auto-towing cables, horse-shoes. Illustrated Books Describing Uses, FREE American Steel & Wire Co, °-B=sts5V-F,and@ SA. Statement of the Ownership, Management, Circulation. etc.. required by the Act of Congress of August 24, 1912, of Popular ficlonas T° published monthly at New York, a . for a ae , 1920.- State of New thea law , deposes and says that he is the Business Manager of the "Popular Science Monthly and that the following is, to the best of his knowledge and belief, a true statement of the ownership, management, etc., of the aforesaid publica- tion for the date shown in the above caption, required by the Act of August 24, 1912, embodied in section 443, Postal Laws and Regulations, printed on the reverse of this form, to wit: 1. That the names and addresses of the publisher, editor, managing editor, and business managers are: Pub- lisher, The Modern Publishing Com any Inc., 225 West Thirty-ninth Street, New. York, N Editor, Waldemar Kaempffert, 225 West Thirty-ninth Street, New York, N. Y. anaging Editor, Waldemar Kaempffert, 225 West Thirty-ninth Street, New York, N. Y. Business Manager, . Capen, 225 West Thirty-ninth Street, New_York, N. 2.—That the owners are: The Popular Science Publishing oo mpany Inc., 225 West Thirty-ninth Street, New York, tockholders of Popular Science Pub- ag 3 Tana: Inc., Henry J. Fisher, 22 William Street, New York, N. Y.; Oli ver B. Capen, 225 West Thirty-ninth Street,New York, N. Y.; Robert Cade Wilson, 683 Spri: 8 field Avenue, Summit, N.J.; Waldemar Kaempfiert, 225 West Thirty-ninth Street, New York, N. Agnew, 22 William Street, New York, N. Y.: Susan D. tise, 22 William Street, New York, N.Y. 3.—That the known bondhoiders, mortgagees, and other security holders owning or holding 1 per cent. or.more of total amount of bonds, mortgages, or grt securities are: Importers 7 Traders National Bank, 247 Broadway, New York, N. Fisher, 22 William Street, New York, N. y. 4. ange the two paragraphs next above, giving the names of the ow ners, stockholders, and security holders, if any, contain not only the list of stockholders and security holders as they appear upon the books of the company, but also, in cases where the stockholder or security holder appears upon the books of the company as trustee or in any other fiduciary relation the name of the person or corporation for whom such trustee is acting, is given; also that the said two paragraphs contain statements embracing affiant’s full knowledge and belief as to the circumstances and conditions under which stockholders and security holders who do not appear upon the books of the company as trustees, hold stock and securities in a capacity other than that of a bona fide owner; and this affiant has no reason to believe that any. other person, association, or corporation has any interest direct or indirect in the said stock, bonds, or other securities than as so stated by him (Signed) O. B. CAPEN, Business Manager. orn to and subscribed before me this 17th day of September, 1920. rthur A. Blauvelt, Queens County—2767, New York County-639, New York Reg. 1 (Seal.) My commission expires March 30, 1921. 140 Popular Science Monthly turn the wheels away from it. If you do find yourself in this predicament, and all efforts to turn the wheels sufficiently to effect a getaway prove of no avail, put the jack under the center of the front axle and raise it a few inches. Then push the car away from the curb and off the jack. The slight drop won’t hurt the car and it will get the inside wheel far enough away from the curb to make it pos- sible to maneuver your way clear. A Holder for Varnishing Casting Patterns ATTERNS for castings are var- nished all over with shellac varnish. The parts that are to be reproduced in metal are finished with black shellac and the core- prints, which make the re- cesses in which the cores are placed, are fin- a been ished in orange Three sherv prongs stp shellac. hold it until the varnish In order to_ is applied hold the pat- tern while applying the varnish the tool here shown is very convenient. It is simply a handle with three thin, sharp prongs that are thrust into the wood just enough to give a hold. When the work is finished, a rod is thrust through a hole running the length of the handle and the pattern is pushed from the holder. PUSH-ROD PRONGS To Protect the Handle of Your Percolator HE wooden handle on your coffee percolator can easily be protected from burning off at the bottom by attaching this small protector, which deflects the heat from the bottom of the handle. A small piece of aluminum, brass, or copper will answer the purpose if bent into the shape W Pcecovator HANDLE «Shown in the illustration. It is attached to the handle by bending the 4 outer flaps over o> unes| the top of the This small metal pro- lower handle tector preventsthefire @nd braced se- from burning the per- curely. colator handle This was found to be very efficient, and if the same is done to your percolator, it will prolong its life considerably.—H. E. MENDE. What the Small Vise Will Do O owner who does any repairing L or tinkering with his car should be without a small vise. Next to such indispensable tools as screwdriver, wrenches, and pliers comes a small ee =a a. ee fk ae ee > ch 2h t=etee 22 2h 4 Sr etc aa Tr =e Fe met eee AF = et eS AO Oe —“ et rt CO oO.

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December, 1920 metal vise. You can buy such a tool as we have in mind for very little money. Get one that has a spread of 3 or 4 in., and you will wonder how you ever got along without it. This size is better than a larger one for the reason that for all ordinary work its spread is amply large, and it is much easier to manipulate a small tool of this kind than a large and cumbersome affair. The big thing about a vise is that it grips—acts like an extra pair of hands when you have more things to hold than you have hands. A small vise also can be used advantageously in place of a pair of pliers for straighten- ing wires, cotter-pins, and similar articles, and it has a great deal more straightening power than can be exerted by hand with the pliers..- For compressing small springs a vise. can also be used handily sometimes. Another Use for the Old Inner Tube N the summer hot air is apt to arise from around the pedals of an automobile, and in the winter it it is liable to be decidedly chilly. To be able to ex- clude these dis- agreeable gusts of air may not seem easy, but here’s the way to do it. Cut out a sec- tion of old inner tube and make a slit down the middle long enough to allow A piece of old inner tube tacked around the pedal to be the pedal prevents Worked its full hot and cold air from distance. Slip striking your feet the slit over the pedal and down the ‘shank and tack it to the under side of the floorboard. The rubber will always hug the pedal shank close enough to keep out the drafts, and yet will not in- terfere with the operation of the pedal itself. —WINDSOR CROWELL. PEDAL: INNER TUBING : Te Select Speedometer Gear Sizes HEN you change from normal size to oversize tires, it will be necessary to change the speedometer gear if you want the instrument to read absolutely accurately. The rule to follow is that the number of teeth in the large speedometer gear—the one attached to the road wheel—must be twice the diameter of the tire in inches. For instance, if your car is equipped with 32 by 31% in. tires, the speed- ometer gear should have 64 teeth. But if you put on the oversize tire that fits the same wheel, 33 by 4, the large speedometer gear should be changed to a 66-tooth size. ITVAVLETTNL: | | i

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“HURWOOD” Screw Drivers Unsurpassed for Strength and Durability Blade, Shank and Head— one piece of special steel, finely tempered. The blade cannot turn in the handle. The assortment illustrated above is well worth your at- tention. For instance—No. 21 shown at the extreme right of the pic- ture—blade only 1% inches long, just fits the vest pocket, a strong little Driver and very handy. Also No. 60—shown at the left—only 15% inch blade, but with a big sure grip handle. For heavy work into close cor- ners it cannot be beaten. Used by Plumbers, Machinists, Mill- wrights, etc. Nos: 51, 52 and 53—called MACHINISTS’ DRIVERS —big, broad tips for large screws and extra large shanks for heavy work. Nos. 5114, 5214 and 5314— also Machinists’ Drivers, have hexagon nut on shank for" use with a wrench. ae No. 54—Note the DOUBLE GRIP, also the hexagon fea- ture for wrench. With the latter Driver one can turn anything. We make many other drivers. See Catalog No. 34S. At All Hardware Dealers STANLEY Rute & Lever Co. New Baitain, Conn. U.S.A. Popular Science Monthly Knurling on the Small Lathe By H. H. Parker HE amateur sometimes is unable to finish small parts of his home- built apparatus in a workmanlike manner because he lacks the proper equipment to knurl the edges of small adjusting screws and nuts, the handles of tools and other pieces of brass or steel. Satisfactory knurling may be performed with simple apparatus on almost any small speed lathe or screw- cutting lathe, and the knurls them- selves are all that it is really necessary to purchase. These come in a large variety of patterns, straight, angular, and crossed with coarse, medium, and fine pitch, straight, convex, or concave faces, as well as more complicated and fancy patterns. For all-around work the medium-pitch diamond-pattern straight-face knurl is perhaps the best. A concave-face ‘woes straight-cut pattern is useful for finishing small binding - screw thumb- sn able pressure is required, and this will be especially hard upon a small lathe. A special type of holder containing a swiveling head and two knurls is in the market, and while this would be an improvement for use upon a medium or heavy lathe, the side pressure is still present. The way to overcome this difficulty is to use three (or perhaps two set diametrically) knurls and a self-contained means of applying the pressure, thus balancing the device and removing the strain from the lathe. Many forms have been devised for this purpose and Fig. 3 suggests one that can be built up from bar stock and which has a wide range of _adjustment. The pressure is applied to the work by means of the wing-nut and the’device is entirely independent of the lathe-car- riage. Another way would be to make three adapters to clamp to the jaws of a universal lathe-chuck and hold the chuck in the tailstock FIGI. nuts and similar . by. means‘ of a small work. It | a is specially made should beremem- ean adapter fitting bered that the i i oe ROOK into the tailstock harder the ma- / o ERR quill; the. pres- terial to be FiG.2. FIGS. sure would then knurled or the os be applied by the coarser the pitch ‘ regular ~ chuck- of the knurl, the key. more power is re- WEST QD —_rovusting roves) Frequently quired and the ss ad fr : = upon knurling a greater the strain — ae 4 2S. piece of work, the on the lathe. otter or} pitch, instead of In regard to , / appearing like holders, the ‘a lo Ol! 00g O00 Fig. 5, for in- simplest is that — oe stance, matching shown in Fig. 1, FIG.3. the knurl, is a split or forked : end drilled for Fig. 1. the knurl-pin and provided with a wooden handle at the other end. Such a_ holder may be bought or is easily constructed at home and is suitable for a small speed lathe, either foot or power driven. The work should be held in a chuck and driven at high speed and the holder applied by hand, using a T-rest as in wood-turning.' The pin should be oiled frequently. By bring- of Fig. 4 | ing the knurl up under the work with the holder resting on the rest, the necessary leverage may be obtained. If the lathe is provided with a slide rest, a simple holder, shown in Fig. 2, holding a single knurl, may be made. The lathe is first set in motion and then the cross’ slide moved up until the knurl- presses against the work, care being taken to set the holder at right angles to the lathe-bed. Though satisfactory work may be performed with these holders using one knurl, it can be seen that there is always a cer- tain amount of strain upon the lathe- spindle and cross-slide, since consider- 142 A hand knurling-tool. Fig. 2.A single knurl tool post-holder. Fig. 3. Ad- justable knurl-holder for a lathe. Fig. 4. As work sometimes appears. Fig. 5. As it should appear. Fig. 6. Explanation much finer, some- thing like Fig. 4. This is a puzzling difficulty until we stop to think that knurling is something - like cutting a gear—if the gear blank is not turned the proper diameter, the last tooth cut will overrun the first. ad This is what happens if the work to be knurled is not the right diameter— the knurl teeth will overrun,and form a series of fine pitched teeth. \It is, however, not worth while” trying to figure out the correct work diameter, for this does not happen very .often and when it does, the - trouble is usually obviated by taking® ‘a light cut over the work to remove the marks; then apply the knurl again as usual. As knurling increases the diameter of the work’ over the points of the ridges, it is a means often-used to make a pin or bushing fit which was formerly too loose in its hole, and this is often the only way to correct a piece of work turned down too small. Decer mean: per c and |

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December, 1920 A Startling Memory 141 Ca That You Can Do How I learned the secret in one evening. It has helped me every day HEN my old friend Faulkner invited me to a dinner, party at his house, I little thought it would be the direct means of getting me a one-hundred-and-fifty per cent. increase in salary. Yet it was, and here is the way it all came about. Toward the close of the evening things began to drag a bit, as they often do at parties. Finally some one suggested the old idea of having everyone do a. “stunt.” Some sang, others forced weird sounds out of the piano, recited, told stories, and so on. Then it came to MacDonald’s turn. He was a quiet sort of a chap, with an air about him that reminded one of the old saying that “still waters run deep.” He said he had a simple “stunt’’ which he hoped we would like. He selected me to assist him. First he asked to be blindfolded securely to prove there was no trickery in it. Those present were to call out twenty-five numbers of three figures each, such as 161, 249, and so on. He asked me to write down the numbers as they were called. This was done. MacDonald then astounded everyone by repeating the entire list of twenty- five numbers backwards and forwards. Then he asked people to request numbers-by posi such as the eighth number called, the fourth number, and so on. Instantly he repeated back the exact number in the position called. He did this with the entire list—over and over again, without making a single mistake. _Then MacDonald asked that a deck of cards be shuffled and called out to him in their order. This was done. Still blindfolded, he instantly named the cards in th eir order backwards and forwards. And then, to further amaze us, he gave us the number of any card counting from the top, or the card for any number. You may well imagin e our amazement at Mac- Donald's remarkable feat. You naturally expect to see a thing of this sort on the stage, and even then you look upon {ft as a trick. But to see it done by an everyday business man, in plain view of: every one, blindfolded and under conditions which make trickery impossible, is astonishing, to.say the least. * * * * * * * ON the way home that night I asked Mac- Donald how it was done. He said there was really nothing to it—simply a memory feat, the key to which anyone could easily learn in one evening. Then he told me that the reason most people have bad mem ories is because they leave memory development to chance. Anyone could do what he had done, and develop a good mem- ory, he said, by following a few simple rules. And then he told me exactly how to do it. At the time I little thought that evening would prove to be one of the most eventful in my life, but such it proved to be. What MacDonald told me I took toheart. In one evening I made remarkable strides toward improving my memory and it was but a question of days before I learned to do exactly what he had done. At first I amused myself with my new-found ability by amazing people at parties. My “memory-feat,’’ as my friends called it, surely madea hit. Every one was talking about- it, and I was show ered with invitations for all sorts of affairs. If anyone were to ask me how quickly to develop social popularity, I would tell him to learn my memory “feat’’—but that is apart from what I want to tell you. The most gratifying thing about the improve- ment of my memory was the remarkable way it helped me in business. Much to my surprise I discovered that my memory training had liter- ally put a razor edge on my brain. My brain had become clearer, quicker, keener. I felt that I was fast acquiring that mental grasp and alert- ness I had so often admired in men who were spoken of as.‘‘wonders” and ‘“‘geniuses.’”’ _The next thing I noticed was a. marked improvement in my conversatio powers. , habit of calling me in whenever he itions, ; . my memory Formerly my talk was_ halting and disconnected. I never could think of things to say until the conversation was over. And, then, when it was too late, I would always think of apt and striking things I “might have said.” But now I can think like a flash. When I am talking I never have to hesitate for the right word, | the right expression or the right thing to say. It seems that all I have to do is to start to talk and . instantly I find myself saying the very thing I want to say to make the greatest impression on people. It wasn’t long before my new- found ability to remember things and to say the right thing at the right time attracted the attention of our president. He got in the wanted facts about the business. As he expressed himself to me, “You can always tell me instantly what I want to know, while the other fellows annoy me by dodging out of the office and saying ‘I'll look it up.’ ”’ * a ae I FOUND that my ability to re- member helped me wonderfully in dealing with other people, particularly in committee meetings. When a discussion opens up the man who can back up his statements quickly with a string of definite facts and figures usually dominates the others. Time and again I have won people to my way of thinking simply because I could instantly recall facts and figures. While I’m proud of my triumphs in this respect, I often feel sorry for the ill-at-ease look of the other men who cannot hold up their end in the argument because they can- not recall facts instantly. It seems as though I never forget anything. Every fact I now put in my mind is as clear and as easy to recall instantly as though it were written before me in plain black and white. We all hear a lot about the importance of sound judgment. People who ought to know say that a man cannot begin to exercise sound judgment until he is forty to fifty years of age. But I have disproved all that. I have found that sound judgment is nothing more than the ability to weigh and judge facts in their relation to each other. Memory is the basis of sound judgment. I am only thirty-two but many times I have been complimented on having the judgment of a man of forty-five. I take no personal credit for this—it is all due to the way I trained my memory. a tt SS. e- 6 SB 8 (THESE are only a few of the hundreds of ways I have profited by my trained memory. No longer do I suffer the humiliation of meeting men I know and not being able to recall their names. The moment I see a man his name flashes to my mind together with a string of facts about him. I always liked to read, but usually forgot. most. of it.. Now I find it easy to recall what I have read. Another surprising thing is that I can now master a subject in con- siderably less time than before. Price lists, market quotations, data of all kinds, I can recali in detail almost at will. I rarely make a mistake. My vocabulary, too, has increased wonder- fully. Whenever I see a striking word: or ex- pression, I memorize it and use it in my dictation or conversation. This has put a remarkable sparkle and pulling power into my conversation and business letters. And the remarkable part of it all is that I can now do my day’s work quicker and with much less effort, simply because my mind works an = = and I do not have to keep stopping to look things up. Al this is extremely ‘eatist ying to me, of course. But the best part of it all is that since er first attracted the attention of our president, my salary has steadily been increased. Today it is many times greater than 3

it was the day MacDonald got me interested in improving my memory. Sy £2 8 os Se Oe @ HAT MacDonald told me that eventful evening was this: ‘‘Get the Roth Memory Course.’’ I did. That is how I learned to do all the remarkable things I have told you about. The Publishers of the. Roth Memory Course— The Independent Corporation—are so confident that it will also show you how to develop a remarkable memory that they will gladly send the Course to you on approval. You need not pay a single penny until you have examined the ‘Course and found that it fully lives up to all the claims made for it. Send no money. Merely mail the coupon, or write a letter, and the Complete Course will be sent to you instantly, all charges prepaid. If after ex- amination you decide that you do not want to keep the Course, then return it and you will owe nothing. On the other hand, if you find, as thousands of others have found, that the Roth Memory Course will do wonders for you, then merely send five dollars in full payment. You have always wanted a good memory. Now you can have it. Remember, you pay no money until you have proved that the Course will benefit you. You have everything to gain and nothing to lose by taking immediate action. So mail the coupon NOW before this liberal offer is withdrawn. Independent Corporation Dept. R-7712 319 Sixth Ave. New York FREE EXAMINATION COUPON Independent Corporation Dept. R-7712 319 Sixth Ave. New York You may send me the Course or Courses checked below. Within five days after receipt I will either remail them or send you $5 for each in full payment, except as noted. Roth Memory Course ($5) Super-Salesmanship ($5) [] By David M. Roth [] “By Arthur Newcomb Drawing, Art Cartooning Practical C in Per- [] "Coarse ( ) < [] sonal Efficienc; $5) By Chas. Lederer By Edward E. Purinton How to Read Character Money-Making. Account af Bight ($8) System and Finance By Dr. K.M.H. kford Course 5 By Wesley W. Ferrin P Shorthand ($5) [_] wreesteuct ee . (] ereseeter, WN ha aN 245 ole ne. device ccdan s@ebepine Se by p ecmcen eS ES EPS PT EE Pe ee

| _ a

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Get the facts about ‘the-Chicago ‘‘Tech’’ courses in Drafts-. manship (or any of the other big-paying professions listed on the coupon) which youican master quickly by, spare time study *’ Salaries. paid draftsmen* today, are the highest in. history because trained men are scarce. to go around and hundreds of big jobs waiting: of all kinds—mantfacturers, architects, railroads, electrical’ at home.

Not.enough experts Industries plants, etc.—need proficient mén for their drafting depart-. ments. Experts in this profession,earn $60 to $150 weekly.. No matter what you are doing, this is your big chance. We- will send you without obligation or expense a Free Test Lesson (read details of this liberal offer below). See how well qualified you are before you spend a cent. today. Look into thése opportunities’ Learn how a Chicago ‘‘Tech”’ course will make you the man chosen from among many. Clip that coupon—NOW!

Experts Teach You the Methods They Use The Chicago “Tech” method trains-you under experts who will equip you for an important position in the shortest practicable time. You learn exactly the. methods which they use in their own practical work. They prepare you to rank with draftsmen of long experience.

aot [Send BREE Tat Courses You Can Master Quickly If you want to take up and master quickly any other technical study, the ber of professions that pay handsome salaries. If you can not come to the col- lege, you will get the same course—the same thor- ough individual instruc- tion by mail. No matter Test. ‘Bottle-Caps Do Their Bit. ....... 6 ‘Legs for the Vacuum Bottle 18 Practical coupon above lists a num- * give you the training re- quired in men who aim to hold important executive positions, Why plod along and be content to - take - orders from men who know the “Hows” and “‘Whys” of a big job? You Aave it in you to Give orders, once Shows you how well qualified you are for draftsmanship. Other schools ask you to enroll and send money first. We send the free lesson first. Read it—practice the exercises—no obligation. De- cide for yourself whether you want to the course or not. FREE OUTFIT With our home study course is included a complete set of high gate instruments, drawing board, . -square, etc. me as leadin: where you live, your les- sons are directed and every exercise examined and corrected by experts. Every point is made clear. You learn just what you need to know from prac- tical men who familiarize you with the things that make you worth a darge

your trained knowledge

draftsmen use. Credit _ i you already have an outfit. salary. With the prac-

gives you the confidence to assume charge of the men who do the actual work, The training in Draftsmanship which you get from Chicago ‘‘Tech” experts fits you to step right out and earn a big salary. : tical knowledge gained - from a Chicago ‘Tech’ course,.you will be the man wanted—be- cause you know why things should be done and how to do them, You can start ata good salary. and. win quick promotion. ~~ 2 Find out how. hun- g . Decide Today—Then ACT [indcut how hun; men have paved the way to high positions merely by using their spare time to prepare’for bigger work. Just nut Xin the square on-the coupon opposite the course you want to know about—sign and mail thecoupon. This information costs you nothing—so act today. Chicago Technical College CLIP THE COUPON NOW CHICAGO - = 4

Popular Science. Monthly The Gun that Shoots Gas .................. Newspapers from Slot-Machines......... ... Here’s a Duplex Bodk .................-- te Over the Rockies on a Waterfall Bread without Flour... .... 2.) .0....veccees Sharpening Drills by Machine.............. + The Paint-Sprayer that Can’t Spatter...:.... sSafety Caps Protect Factory Workers........ A Self-Closing Two-Way Gate Irrigation by Horsepower..................- Good Tops Make Good Barrels Setting Jewels in a Watch beeen Vonr Owns Bee. 5. 5 Te ce ee estce A Steel Punch and Bender.................. Safety First for the Machinery Oiler....:.... No Fire on This ROPDONOREMR 5 fish 3's. or0ss's : ).....0:.....05 Moving-Day for the Mummies. ... Rie 8 Bs 3 Seeing Little Things of the Sea.............. ‘An Electric Lamp with Two Bases....:..... To Keep Milk from Boiling Over............ Connecting Manhattan Island with the U. S... Killing a Bear with Electricity.............. Don't Tremble; This Is No Bomb.......... Cutting Uniform Slices of Bread... . 2. 2... Huge Photographs for Movie Backgrounds. . es The Hair-Cut Electrical... .. 24)... .. A Portable Kitchenette............. 25>..3 ee SS 2S) ee pe Oe SS a Germany's Porcelain Money................. ES Se Oe Buy a Tree and Save a Forest............... A Shoe-Shine in Your Vanity-Bag........... Combine the Driveway with the Walk....... Scent Sweetens All the Air................. The Card Tells the Price............. eiehaerse A Headlight for the Walking-Stick........... He Makes His Rounds on Skates............ A Penholder Support...... eo ees Neatly Pinning a Soft Collar................ The Wood that Makes a Sunday Paper...... One-of Our Bird-Veterans........... ena ee aa A Clock that Literally Tells Time........... Rubber Tire Patches Make Good Rubber Heels _ The Coal-Stove Unadorned................. A Spring Hanger for Clothes.,.............. A World's Champion..... ENCE Fe aa Sie tsa ps: aus The Telephonic Eye Betrays the Burglar... .. Keeping Up with the March of Science. ...... Some New Jobs for the Automobile-Jack....... Turn Your Car Over with One Hand.......... This Gasoline Engine Is Handled by a Chauffeur A Boat that Looks Like a Whale............ An Automobils Made of Luggage.....-...... A Motor Snow-Plow for Sidewalks........... Rae ae @ Deley Latte Car... 5. 8 oc chee ee Saving Time Coupling. Tractors and Trailers. . | Watermarking the Radiator................ The Tool-that Tightens Anti-Skid Chains .... A Convertible Automobile Body.... : © Sint Sox arc The Paving Machine with Caterpillar Traction |, This Oil-Cup Works Automatically........-. ’- He’s Harnessed to His Car...........-.. SA An Insulator and Conductor in One........-

1231 Chicago “Tech” Bldg. ILLINOIS Trapping Fires Automatically..............-- (Continued on page 6) & O NTENTS—Continued MOTOR VEHICLES AND ACCESSORIES

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ae ee ee ee December, 1920 Was $100 Now $64 In these days when the . cost of many things is higher than before the war, it is a distinct con- business- economy to offer through more direct selling meth- ods such a great and de- cided saving on so popu- lar a typewriter as the tribution to Oliver, Over 800,000 Sold Send No Money! No money in advance. Notacent! Simply make your request via the coupon below if you want this brand new Oliver Typewriter for five days free trial in your own home or office. Use this Oliver for five days as if it were your own. Type all your letters or any other work with it. Put it to every conceivable test. writer on the market. Compare it for simplicity of For beauty of finish. For ease of operation. For speed. For neatness of work. Then construction. Famous Users of the Oliver Columbia Grapho- phone Co. Otis Elevator Company National City Bank Boston Elevated Railway Hart, Schaffner & Marx U. S. Steel Corpo- ration AmericanBridge ~ Co mpany National Cloak & Suit Co. Compare it with any $100 type- For $64 you can now obtain the Save $36 identical Oliver Typewriter formerly priced at $100. We are able to save you nearly half because of our radically new and eco- nomical method of distribution. During the war we learned many lessons. We found that it was unneces- sary to have such a vast number of traveling salesmen and so many expensive branch houses throughout the country. We were able to discontinue many other su- perfluous sales methods. Result—we can afford to sell at $64 the very same Oliver formerly priced at $100. Mail the Coupon Now Check the coupon to get the Oliver for five days free trial in your own home. If you decide to keep the typewriter‘ you can pay for it on terms so easy that you won’t miss the money—only $4 a month. If you prefer to.have further information before ordering, fijl in the coupon for our free catalog. Clip the coupon now and mail at once. “OLIVER Typewriter Gmpany 1109 Oliver Typewriter Bldg., Chicago, Ill, tg... TT \UeRttttnitaaay { { A Finer Typewriter at a Fair Price if after 5 days free trial you do not wish to keep the typewriter for any reason whatsoever, simply send it back to us and you won’t be out one cent for the free trial. If, on the other hand, you decide that it is the finest typewriter, and you wish to keep it, then pay us at the easy rate of only $4 a month. This is the open, free trial offer we make to you on the Oliver to let you see for yourself that if any type- writer is worth $100 it is this splendid, speedy Oliver No. 9, our latest model and the finest we ever built. Feseeeee ese ee sees eee ese see Sees eseee * THE OLIVER TYPEWRITER COMPANY ' 1109 Oliver Typewriter Bldg., Chicago, Ill, 3 Ship me a new Oliver Nine for five days free inspec- a tion. If I keep it, I will pay $64 at the rate of $4 per *g month. The title to remain in you until fully paid for. 4 My shipping point is os 8 This dees not place me under any obligation to buy. If I @ choose to return the Oliver, I will ship it back at your 2 expense at the end of five days. v Do not send a machine until I order it. Mail me your | book —“‘The High Cost of Typewriters— The Reason fiand the Remedy,” your de luxe catalog and further in- § formation. Name pi seissiaiansldiiial Street AAGAress ...........-...cc.--cceccecscecsereneccoeesessnenen nee == SS

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) BE A CERTIFICATED } ELECTRICIAN © | WILL TRAIN YOU AT HOME Prepare NOW, and be ready ina few months to earn your $65 to $175 A WEEK The country needs thousands of trained, Certificated Electricians to fill good positions—and at big pay. __ It's alla matter of knowing how, and I will teach you by my up-to-date, modern instruction. Youcanlearnat home, without interfering with your regular work, by my highly successful method of Home Instruction in Practical Electricity. A Real Position Like This—for YOU My book, “HOW TO BECOME AN EXPERT ELECTRICIAN,” has started thousands of young’ men on the way tosplendid success. A new edition of this book has just been printed. I want every young man interested in Electricity to havea copy, and will send you one, ABSOLUTELY FREE AND REPAID. Write me today. How I Train My Students As Chief Engineer of the Chicago Engineering Works I know exactly the kind of training a man needs to enable him to get and hold good positions, and to earn big pay. I have trained hundreds of men who are hold- ing splendid electrical positions. Many are now success- ful Electrical Contractors. I give each of my students personal attention andacomplete and thorough training. I give him a SPLENDID ELECTRICAL OUTFIT FREE, and much of the training is done by actual work. When my students graduate and receive their certificate they are ready for a real.position. But still more, at any time you wish -you can come to our splendidly equipped Electrical Shops for special training.. No other school.can give you this. - AReal Opportunity for YOU Wishing is never going to make your dreams cometrue. You've got to study—to-Jearn. A man is worthonly $2 or $3 a day from: his neck dawn—and no more; but there i is no limit to what he can be worth from‘his neck up A trained mind is what. gets the big pay., Its this ier Se that you neeti, and T can train you ina-‘few months: - Are you ambi- tious to make a real success? Then send me-the ~ a ibesaond ‘Electrical Outfit Free ~ To every student T am giving a splendid Electrical Outfit of standari size cal Tools, Instruments, Materials, etc., absolutely. free. . Furthermore, to ‘every. Electricai Student.I give a truly valuable surprise that I can- _. not explain here. : Free Employment Service Iam ‘continually receiving: requests from employers te send them trained Electrical men. I: — my » students to secure good’ positions: I keep in oo Eng. touch with them for years. helping and advis- Cooke. ing them in every possible way. : WRITE NOW—DON’T DELAY. D pt Delay never got you anything. Action is 30Y ca a counts. _ Se get Sunnyside started now. rite me or sen Aue - a ei this coupon right NOW. ¢ L. L, COOKE, Chief Engineer CHICAGO ENGINEER- ING WORKS Sir: Send at once - fully prepaid and entircly free complete particulars of your great offer for this month. DEPT. 30Y MOIGE o cicccccpcovccbcccesecee e 1918 SUNNYSIDE AVE., CERCAGO, Address. ......... ecccccccccccces oeee READ WHAT MY STUDENTS SAY: “I would not take 1,000 dollars and be with- out your course. If I did the years ahead would only be like the few that have passed.” —H. Swiger, Wallace, W. Va. “Have been made Chief Electrician for the Michigan Carbon Works. Give your course all the credit, and am doing fine.""—A. F. Klemz, Detroit, Mich. —— - “You will be pleased to learn of my promo- tion to Chief Electrician. It was your course put me where I am. Although only a little over half through your lessons, I have had my wages raised from $75.00 to $375 a month, and expect to do better before Iam through.” —H. E. Wolf, Columbus, Ohio. “During May I made about $65.00 in my spare time. I can hand you the credit because when I started I knew NOTHING about Elec- tricity.""—L. Randell, Ironton, Minn. “When I enrolled—I knew nothing about pay ny Today I am the gbos st paid saat man for the Massena Se & Power Co.”"—C C. Burkhart, Massena, “‘When I enrolled I was skeptical. Now Iam convinced you have a fine method of teaching and can, and will, do all you say.’’—John McGee, New York ‘Ci ty. . **My gross income this week from spare-time work was $60.25. Of this amount I paid out $18.75 foi matertes: leaving a net gain of $41.50. Added to m regular wages ($35 a week) I made this week $76.5 Your Course has, therefore, already doubled my income.”—A. N. Lacey, 1379 Main St., Toledo, Ohio. “‘When I enrolled with you I was only able to make $75.00a month. Today, thanks to' your splendid lessons, I am in business for myself, making over $400.00 a month.""—A. Schreck, enix, Arizona. “In the past ten years I've been doing a lot of studying, both by correspondence and through text books, but never — ws I a able to learn as I have with you. ’—J. Ham, Chief Electrician, Albrigh’ ¢ ‘Goal ce. Tunnelton, Ww. Virginia. —_—_—_— “Four months after receiving my first lesson was made Mine Electrician, at a salary of $250 a month to start, an increase of over $100 over what I had been previously able to earn. And your Course is entirely responsible for my suc- cess.’"-—Robt. C. Dawson, Berryburg, W. Va. “When I starte1 your Course I knew nothing about Electricity. Now, fifteen months later, thanks to you and your splendid Lessons. I not only am considered an Expert, but I am in cha-ge of 6 sub-stations. But better yet, in these same fifteen months I have had 7 increases in salary. I cannot recommend your Course too highly —it couldn't be better." —H. F. Happoldt, 1116 W. Sauphin St.. Philadelphia, Pa. “I am still holding that position with the M inneapolis Steel & Machinery Company, se- cu *on your recommendation.”—A. Swan- son? Minneapolis, Minn. “The outfit is wonderful, so much better «than I expected, and I must say Iam more than * plea with -same.”"—F. X. Droege, Coving- ton. Ky. ““Must.compliment you on the very thorough instruction given in motors and motor mainte- —— I am an old hand at this work and know tien things are well handled.”—B. G. Dahl, . Fort Ferry, N. Y. - Your Course of Study has done a great deal for me. When I enrolled I was working for somebody else, but now I am in business for myself, a Licensed Electrical Contractor, and have five men and a helper working for me.”"— Jos. A. Stueber, St. ‘Louis, Mo. Ae yy onl: now a L’ lectrical me and in business for 5. eg averaged $20 to $30 a week on work done after school hours, on on — days.’’—Roger Smith, Greenville, Complete Letters Sent When You Write Me 46, and ¢ and still in school, I am 6 Popular Science Monthly CONTENT 'S—Continued NATURAL SCIENCE Why Aren't Wé Killed by Hailstones? An Arch Made of Bamboo Trees .’. Thirteen™ Billion | Buns. :... Winter" and Water, Nature Sculptors. . PICTORIAL PAGES How Furs Are Made into Garments How the Big Searchlights Ate Tested “The Earth Trembled; the Heavens Dropped” Homemade Kicks New Jobs for the Phonograph v3. To See what's Ifside Fechting the H.-C. L. at the Furnace. ousekeeping Made Easy,” .. . Multiplying Man’s Power * Machinery.. Do ‘You Own a Car? A RE ree SPORTS AND: “PASTIMES —~ A Neéw Way of Riding the Railroad One Good Bath Deserves Another The Barracuda and the Blimp The Gun that Folds Up. .- Making a Finy Circus He Made His Own Stop-Watch Chess-Playing by Wireless A Headlong Flying Leap on Skates A Sled Propelled by Hand Bobsledding when there's No Snow PRACTICAL WORKERS How to Build an Icemobile How to Clean a Clogged Fountain-Pen Compressing Piston-Rings To Clean Valve-Stems Leveling Liquids with a Siphon Reducing the H. C. L A Tire-Inflation Scale To Make Cardboard Models of Resincs , Your Storage Battery in Cold Weather Using a Dial Indicator as a Sweep Tester Home Soldering Made Easy A Burglar Alarm and Keyhole Lighter A Small Farm Tractor Winter Weather Is Hard on Tires Making a Drain-Pipe Overflow How to Case-Harden Articles An Adjustable Handle for a Mirror How to Make Rings of oo Areas An Aquarium Air-Pump.. A Graduated T-Square Old Materials Made This Useful Forge To Throw Lines Over High Objects A Safety Spark-Plug Carrier Box A Lard-Can Used to Dry Fruit In Roll Your Ladder Instead of Carrying It To Protect Your Tires and Tubes Refinishing Worn Shoe Toes Brass Tools for the Making of Fillets Worn Insulation in Automobiles An Easy Way to Take Bitter Medicine. . The Microphone Enables You to Hear a Fly Cutting Large Holes in Metal Plates........ A Surface-Gage Wrinkle.................... A Safety Clip for Your Spectacle-Case....... To Lock ae Garage Door... os... 0 ccc cscs Working with Limit Gages................. Don’t Perfume Your Artificial Ivory A Light-Reflector from a Tin Can =; Adjustable Centers for Small Lathé-Work. The Way to Drill a Triangdlar Hole’. Increasing the Usefulness’ of a. Wagon xenoh - . A Copying Idea for the‘Photographer. . - sa pag A Way to Remove Stubborn Nuts. ...... : How Street Curbing Injures Tires. ..... sik . For Varnishing Casting ‘Patterns’: PEE To Protect the Handle of Your, | Percolator . What the Small Vise Will Do. > ........... Another Use for the Old Inner Tube........ Speedometer Gear Sizes................... Knurling on the Small Lathe.............. a ey eee eee ew ee te eee eeeene Rover Makes a Clever Caddie... : “ : * : : : ; : ae An Experiment for the Flashlight Mitegmaiiaie Secret Marks Aid the Identification of Your Car An Attachment to Prevent Deor-Slamming : ; ; Improvising a Simple Oe aes A Mirror Aids in Placing Phonograph Needles. A Sacking Device that One Man Can Operate An Automobile Jack that Is Quick Acting.. A Quick Way of Tightening Loose Plywhests. _ 8 Weatherproofing Brass Surfaces . e at edi "2s Have You a Step-Saving House?...., he ee Finding the Right Key Made Easy.......... How to Cut Your Canary’s Claws.......... A Circular Saw Attachment Hastens Production Electrifying the Ford Tail- and Dash-Lamps. - Glass Drill Made from a File, .:...:7....... Flexible Pipe Made of Inner “Tubes! 2273002... The Most Efficient Part of an Automobile. Es Repairing a Broken Lug with a:Washier..\....... How to Make a Double:Center Punch... .... ; When the Wind-Shield Rubber’ ‘Wears Off... ‘ Combining a Flagpole with, Advertising. . os a The Vacuum Cl¢anér in a New. Role eer a ena ; To Space and Ink ‘Lines i ina Hurry’ Pe ak es ’ C1) 05 08 & ig Pet eek terete ied 2A... lee VP elk Ti T Ti Ti Oaa

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a a ee ee ee ee ee WONN = =O PES SSS SSS SONATAS SSS December, 1920 ike Big Money Any Young Man, Mechanically Inclined, Can Quickly and Efficiently Fit Himself to Earn Big Money by the SWEENEY SYSTEM. Thissystem of practical instruction teaches men to be mechanics and experts in all branches of the automotive industries. Only at the SWEENEY SCHOOL can you get this system which has been endorsed by government and technical experts everywhere, and proven by years of success and the testimony of 35,000 graduates. Sweeney trains by having you do the work with your own hands. Hand, eye, and brain are trained together. Previous experience is not needed. Books are not used. Learn in 8 weeks and then step out into a big paying job with unlimited possibilities. We're ready for you and a bigger and better jab. $150 to $400amonth The Million Dollar Sweeney School is pre- paring men to earn from $150 to $400 a month in the Automobile and Tractor busi- ness. Take the TIRE business for instance. Big money in that. I teach you the whole business thor- oughly. How to sell. How to repair. How tv make tires. Howtotakeafew _ ‘cents’. worth of Junk and make-a $35 tire. | The state of Missouri alone bought $25,000,- 000 worth of tires last year. The going’s good. Bean expert. No previous experience needed—if you are mechanically inclined the Sweeney System trains you in 8 eeks. PICK YOUR JOB Farm Mechanics $100 to $200 mo. COME TO THE SWEENEY SCHOOL OF AUTO, TRACTOR and Aviation Mechanics if you really wish to be a trained Expert and to work on the most modern machinery; come today for to- morrow never comes. Pack your grip and let’s go. . | FACTS ABOUT THE | SWEENEY SCHOOL Over 187 acres shop and operating space. Over 1 Million Dollars invested. Equipment alone worth over $350,000, of which $50,000 machine shop and aviation equip- ment has just been pur- chased. Over 1,200 students and FARM BY MACHINERY cee Ts 9 {5.500 Lay dk ovva'nsns oni $125 and up 35,000 graduates. On our great Tractor Farm you learn Gheutloure sor. 2c000000000000000 000008 and ap 250 instructors and em- by actually handling over 18 different eoeecececesesrecetesescece u : Repair Men... piovboleniuebsses es sstlg&S per hour $30°000. a eee se makes of Tractors. You learn all See, Bees about pond ee ee on any CSE ee meEie ciples of lighting plants, how to Garage Manager...... 0-0 cseeeesssecceeee $3,000 a year fix up any motor or truck, in general all machinery on the farm is simple and easy to the Sweeney Graduate. If You Are Discontented remember that you can not suc- Rta ceed unless you like your work. But if you like it you find it easy to make good. If you are mechanically inclined write me today. But, if not, don’t bother me. You don't need books. You don’t need education, but you do need a.natural liking for mechanics. I teach you by WORK. You use tools not books. I made a success out of a deaf and dumb man. But unless you are willing to get grease and grime on your hands you can’t learn here. For this is the school of practical experience. ca GET ONA TRAIN—LET’S GO. One-third of our men A ft come here straight off—without long TRADE’ correspondence. I guarantee to refund your railway =F fare, round trip, if you find a single misrepre- & sentation. Simply tell me when you will \ arrive, and you'll find your name on the bulletin board, class as- signed, tools ready for you, room waiting you. Only white 4 students accepted. PACK YOUR GRIP AND LET'S GO. SS Earnestly yours, aS EMORY J. SWEENEY, Presiden:. NS LEARN A TRADE~ EMORY J. SWEENEY, President 801 Sweeney Building, Kansas City, Mo. Send me free your 72-page catalog and Sweeney School News and tell me of the opportunities in the auto and tractor business. h SCHOOL OF AUTO-TRACTOR-AVIATION 801 SWEENEY BLDG. KANSAS CIFY.MO s ARTIST PRE REET

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Rate 30 Cents a Word. Advertisements intended for the February issue should be received by December Ist. MOTORCYCLES, BICYCLES, SUPPLIES AUTOMOBILES AND ACCESSORIES WANTED 7 Pay MOTOR DUPELIES Bach 8 oot Sted- CASH: Paid! if you want all your goods are worth, MOTORCYCLES $40.00 up: Side Cars, Evans Powel Serve. Cae lac, Overland, E. mail us discarded jewelry, gold crowns, bridges, Johnson ‘Motor Wheels, and other light, motor ood Buds MM Faiseeens Sistas Special high . platinum, magneto and contact attachments Send for ow Bie Bergsia and our tension 2 and 4 cyli ts. We 1.00 to $25.00 per set for false teeth oney Saving Message to Motorcyclist™ (illustrated). and gas head lamps, ken or oe sent by return mail. Packages held tes will 3 Ld you money, on pao side cars, Dicycles, ggnerators Sales Dept. ‘Seek bee “Pieswureh, Benmyt. 1 gnustectory, Bend ve the ola o. United States vide aeeellons: Siaser Coehe Comeesy, pa ay Smel 5 si. ipvat, your ser servi ieeiioas Motor mpany, AUTOMOBILE Parts for all of manufac- hg bt and steam electric USED Motorcycle Bargains: Indians, Excelsiors, Har- turers’ list price. connecting cam shafts, | drills, motors, ete 4 cash Pres ne good | leys. $40.00 up. Singles | = twins. Overhauled, rebuilt Famed meg oes and gears. Our new cata- material. Johnston, West Pennsytvania. and tested by experts. Shi “We furnish and guaran- leoay pa Parts Bulletin now ready. Exe et ——s — food. Send stamp for Bis Free List. Largest "Motorcycle to-day. Service satisfaction era? , ng WE. pay ighest prices enenan platinum, ces. er, Desk otorcyc Bro = . Poitis old false teeth, gold or sliver or ae in Western America,” Denver, : ores ar Vuleanining auto tires isa growing and profitable ds and Stamps. them to us to-day by re- : aok tol business. learn. Instruction book, $1. ra turn mail. Goods returned in ten days if you ia foe "Advertising “Ra Rate Folder. oa . S $50 to s8006 1 ls free. Equipment Co., 17 Canal, The Ohio Smeiting & Refining mpany, 238. Lennox some reall t facts which will prove. interesting cinnatl Ohio. Building, Cleveland, Ohio. ~~ v: le to you ty Prodi How ‘You Can Use TENTS—Write for Free Illustrated Guide Book LIVE wire manufacturing company desires of | know, wouldn't you? er fed Advertisi sing and Lvidence of Conception Blank. Send model-or sketch merit to develop and market. Royalty basis or hase ; 2 (Concent Seen. "Sead mabgels patent outright etal Blettner 7% ee ee Popular Science Sronthiy, O28 West 39th Street, New able nature. fi hest references le Jackson Boulevard, Chicago Reason a Victor J. Evans & Company, 189 Ninth, Washington, D AUTO-TOP and seat. covers, $7 up, pares post, prepaid. Easy to apply. Catalogue and samples free. Auto Equip- ment Company, 20 Canal, Cincinnati, Ohio. BLUEPRINTS—aAutomobile generator armatures. See Charles Ghittenden. A Big Advertiser Speaks ad under “Electrical.” SPEEDSTER and - bodies. Re our own— i LES ; Bre, Te nherth Chine tl 8 Syatem sath _— Popular Science Monthly, INSYDE Tyres, inner armor for automobile tires. yeevense _pencees and blowouts; doubles mileage of any tires. free. Accessories pera ee Details American Co., pase T-1 Cincinnati, Ohio. NEED-A Windshield Cleaner, one rub keeps glass clear => hours, from rain, ste itieet and fog. Fastest selling auto accessory Agents— ig profit. Auto Owners’ Supply Company, Davenport, a, NOTICE to auto owners using five inch tires and under. My invention will give at least twenty thousand miles per tire, eliminate blow outs, reduce punctures ninety per cent. Cost -¥ exceed half ice of one tire.. You ——e = _———. Absolute guarantee or money “2% lustrated instructions. send send = to B. F. Spencer, Box 213, Los Angeles, Californ 15% to 20% more power, %/ less gas and no carbon when the air is moist as it is = Gh. ~] Get these results So." Practionhty ‘as a “Conigtete capetigned’ te c: z! no e le = structions $1.00. Satisfaction or mone. refunded. Cari Laidlaw, Graettinger, Iowa. FORD ACCESSORIES FORDS start easy in cold weather. Will run 34 miles wi ourself. Big ‘antee; em, Gave trial; Au Frietio FORD Valve adjusters make your Ford engine abso- lutely Let gw = ore power, saves gasoline. ice com- = set $1.00. Leitner Mig. Gonlpany. 4430 Bernard, cago. $2.50 will bring you the Best tire holder for Fords. Carries two tires. Has locking device. Dealers wanted. Struthers Mfg. Company. Peoria, Illinois. MR. ADVERTISER: Ask sotag Se a copy of the “Quick-Action Advertising Rate Ider.” It contains im; acts which will prove mares . It also tells “How You Can Use ence Monthl Ra, a You'd like to know, —s as ee Classified Advertising, gal onthly, 23! 235 West 39th Street, New WELDING AND. SOLDERING WELDING apparatus for all purposes. Small payment, ge e to ten ing. Write ton mechanic needs « one. te to-day. interesting. Bermo Welding a Boder's Rapids, Iowa, U.S. A MOTORS, ENGINES, MACHINERY eMart, Motors and ares yh. c. $26.50, \% h. p. 50, 4, h. p. $67.50. isattery nn a ting and moving poenene one phases of curren Promp t P'Ganeery. Wholesale prices. Write for late a Address Motor Sales Dept. (14), West End, Pittsburgh, y a 4 ELECTRICAL ELECTRICIANS, Wiremen, Linemen, send your name and address for descriptive literature of our Modern Blue Print Chart Method of a Wiring. Over 350 ical diagrams. Electrical Wiring Diagram Company, x B173, Altoona, Pennsylvania. MAKE Dry Batteries. Simple, - instructions, _— blue print, 25 cents. Dir les Company, Bath, aine. BLUEPRINTS—Electrical connections. Alternating and direct current motors, transformers, rheostats, con- llers, compensators, automobile generator armatures. samples A.C.25c. Particulars free. Charles Chittenden, atthews Avenue, Kansas City. Missouri. EXCHANGE SWAP baa Three months, dime. Circulates rT Circulars mailed, Advertisements, cent 8 225 West 39th Street, New York City. Gentlemen: Our experience in the classt- fied columns of Popular Science Monthly has been very satisfac- tory. The results received have been from high-class specialty salesmen who are the only kind that can sell our high-grade line of products. We manufacture a line of food products and toilet preparations that are above the = average, require both men and women of ability to sell them, and we have found that we get this class of people as the result of our advertisements in -your classified section. Needless to state we will use Popular Science Monthly regularly. Very truly yours, AMERICAN Propucts COMPANY This well-known concern is undoubtedly one of |the biggest classified advertisers in America. today, and it is reasonable to as- sume that they are experts in the matter of selecting the proper type of medium to carry their message to the public. - They maintain a most complete system for key- ing their advertisements, which enables them to tell:at a glance exactly what each advertisement, in each issue of each publi- cation is producing. The fact that they haven’t missed a single issue of Popular Science Monthly in over five years should answer YOUR questign—* Does it Pay?” Classified Advertising Manager POPULAR SCIENCE MONTHLY 225 West 39th Street New York City AVIATION THE comity School of Aviation announces ‘a~ new. mn correspo! ough radaing 1 ay Pract ical aeronautics. Amer Aviation, Dept. 1899, 431 South, Deatbore Street, Chieago. INVENTORS desiring information write for our Free Illustrated Guide Book and Evidence of Co tion Blank. Send model or sketch of invention for our 0) pale 3 Ld patentable nature. ighest_ references. Reasonable terms. . Victor J. Evans & Gengnay, ts. inthe Washington, D. C. BUILD the Star Jr. Biplane. font stamp for Circular “Pp.” Chicago ‘Aero Werks, 326 River. Quick-Action Advertisements continued on page 10 MANUFACTURING WE.do ers Soe Gold, Bliver, Nickel, Brass and ogee, Somes ~ ML manufacture your:article either tract basis. in large production write us. When on your owe work you are always welcome ‘at our 8 bench. enning Mfg.” Company, 1775- East 87th Street, Chovelnnd, Ohio. . FORMULAS DEPENDABLE formulae for Automobile, Toilet and Food 8; including Industrial Processes. Lists 2c. Ind ‘Methods Bureau, 1B West 34th Street, New y. York Cit; 500 FORMULAS. Trade Wrinkles, Secrets, Discoveries. All oe. —— money-makers. Lis free. Every- —~ B Edgar James, 315 Bousias, -Indianapolis, 1,000,000 FORMULAS. Trade secrets: 1016 pages $2." ‘Ideal,’ 5501-PS, North Robey, Chicago. LONDON Jack's stovepipe and aipany, cleaner formula 25c. Charles Dynes, Winchester, Indian: SHOE Polish Formulas =} ane. Street, Brockton, Massachuse FIFTY crackerjack formulas—no impractical antiques— automobile specialties, enamels, porns. ce cements, etc., fifty os cents. wore on Specialty Bureau, P. O. Box 406, "Brooklyn, ew Yor L. Allen, 566 Main DRAWING INSTRUMENTS 200 COMPLETE sets of Mechanical ‘grawing instru- ments must be Sacrificed regardless of the cost. These mechanical drawing sets must be sold within 30 days—at less os wholesale —. You will oo the wholesaler’s profit and the retailer's. t by tak is wonderful opportunity now. If youd a eed #e will get the biggest bargain ever offered i draving instruments. Send .for our illustrated p part oe ediars National In- Fremnt Company, 4517 North Lawndale Ave., Chicago, no! LABORATORY AND CHEMICAL SERVICE EXPERIMENTAL -Chemistry ‘set for young people. 28 chemicals and 12 pieces of: apparajus. in wooden box with book of instructions and e ments. Everything the very best quality. Price $5 $5.50. -Stamp for illustrated lists. Bathe .~ a Company, Desk. 6, 5214 Woodland Avenue, Philadelph MODELS AND nso SUPPLIES PATENTS—Book free. Send sketch for. Opinior of atentable nature. Talbert & & Talbert, 4848 albert Build- ng, Washington. D. C. Cae oF al brie ponte and model supplies. Send te stock of brass gears and m for catalogue M.—The Pierce Model’ Works, 1837 North Karlov Avenue, Chicago, Illinois. MR, ADVERTISER: Ask _ to-da: “Quick-Action. Advertising Rate for a copy of the older.”’ contains mi meperent ‘facts which will prove interesting and vahi le to you. It tells How You Can Use Popular Science Monthly Profitably. ou'd like to know, wouldn't you? Advertising. M Popular Science Monthly, B28 West Sot Street, New ork. AMERICAN MADE TOYS ers on small scale and Religious desi and other toys and Novelties. chance for industrious peop ~ by BF Leap come ow business. Enormous demand for cheap field and great future all over United States and foreign countries: Experience or tools not ie complete hour. Casting -$3.00 ‘up. Powe buy these a geben, prices. Attractive prices offered for oods. strictly business proposition. No one need apply unless he means business. Booklet — ee ‘furnished bea We have no sales agents and we warn and Toy = M —, anufacturing Com- pany, 32 Union Square, New Y'

Page 135

_ December, 1920 21 Ruby and Sapphire Jewels to the Second to Temperature to Isochronism te Positions . 25~ Gold Strata Case Genuine Montgomery Railroad Dial New Ideas in Thin Cases The @ url ington TheWatchmakers’ Masterpiece Jes think of it! Only $3.50 per month—a great reduction in watch prices direct to , : n Zs = Hi you—a 21 jewel adjusted watch at _rock- : ima | } bottom price. Indeed, the days of exorbitant 2 Nea cc y y) watch prices have passed. See It First You don’t pay a cent to anybody until you see the watch. You don’t buy a Burlington Watch without seeing it. Look at the splendid beauty of the watch itself. Thin model, handsomely shaped—aristocratic in every line. Then look at the works! These you will see the masterpiece of the watch maker’s skill. A perfect time-piece adjusted to \\ JA \ positions, temperature and isochronism. oe, Cle Practically every vessel in the U. S. Navy has many Burling- “ Tr ton watches aboard. Some have over 100 Burlingtons. The e ee weet A 4A victory of the Burlington among the men in the U.S. Navy —— is testimony to Burlington superiority. Send Your Name on This Free Coupon Get the eee Watch iF dae axe coun innings cam ana) came GUD aD aE eam sending thiscoupon : y g -* Burlington Watch Co. now. You will know a lot | more about watch buying 19th St. and Marshall Blvd. when you read it. You will i Dept.1369 Chicago, IIL re able to eo on | Please pend me —mithout ob ion and @ over - pri watches full explanation of your cash or $3.50 6 which arenobetter. Send the I month offer on the Burlington. coupon today for the watch | book and our offer. : Burlington Watch Co. 19th St. and Marshall Blvd. , Dept. 1369 Chicago, Illinois | Canadian Office: 338 Portage Ave., Winnipeg, Man. 1 PETITTTITITiT Tete iii tii) re BAMPEB .. nacre sis coveveccee ccccccccccsccees

Page 136

AUCTIONEERS Quick-Action Advertisements continued from page 8 PRINTING, ENGRAVING, MULTIGRAPHING - Popular Science Monthly POULTRY AND LIVE STOCK

ADCrSSa ES and Bankers make Be pe mone teach both. Free catalog. Missouri A Rae School, Kansas City.

DUPLICATING DEVICES MULTIGRAPH Letters build business. nomical and effective ph Prin Low rates: careful work; service. Multig Letter Company, 241 Pourth Avenue, New 833 FT. LABELS, $2.50. Seve 30 all. Wolf Labels, Se Latte var cis Wo Adareosing.

“MODERN” Duplicator—a Busi Getter, $2.25 up,

klet Free. Pittsburgh, Pennsylvania.

FOR THE HOME

GRANDFATHER'S Clock Works $5.00. —_ BR. Own cases from our free instructions. Everybes a hall clock. You can mone good profit bui ding artistic clocks for your friends. e replace My gl og = in old clocks with works chimes at savin: prices. Write for folder a ing the most beau iful Sook ever sold at $35.00. Clock Co., Nicetown, Pennsyl- vania.

..2iR. ADVERTISER: Ask to-day for a copy of the Quiek-Aetion Advertising Rate Folder.” It contains some real ly im) t facts which = yore inveresting and valuable to you. It also tells * w You Can Use Popular Science Monthly Profitabl Y You'd like to know, wouldn't you? Man: ange asified Advertising, Popular Science Monthly, 225 West 39th Street. New York. LETTERHEADS $2.50 thousand. Samples free. Quality Print Shop, Marietta. Ohio. GOOD Printing Reasonable. Machine composition, automatic es presses, automatic coven machinery. We print Get our ~‘ noe raus, Kraus Building, Mil waulee. Wisconsin CITY printing at country prices. Write for samples and prices. Royal Printing Company, Sugarcreek, Ohio.

“LITTLE WONDER” Crown Capping Machines -_ to every housewife, equal in efficiency to expensive poe machines. Fastest sel Agents, Dealers, write. Mincke, Dept. C., Alhambra, California. MR. ADVERTISER: Ask wey for a copy of the ge Advert —— Rate Folder.” It contains some — t facts which will prove interesting and a= =. It also tells ‘ ‘How You Can Use oo Science — yay A Hema be wouldn't Feutes alae ce Monthly. 2 225 West Son Street, New York.

STAMPING NAMES

MAKE $19.00 Hundred Stamping Names checks: Send 25c for sample and instructions. Ps K A Company, Cohoes, New York.

MISCELLANEOUS -

MASTER KEYS, $1.00. Opens hundreds of diff BETTER printing for less money! Send od ay ares package of samples of hundreds of items e user 0 ting is interested in. These comers worth. Gatlers, will sent for 10 cents to pa pay penen est Fantus Com- pany, 525 South Dearborn Street, ‘Chi cago. GUMMED labels! Rubber ene Catalog free. Edward Harrison, ‘‘Printing,’’ Baltimor

RA poultry A rabbits—we how. Grea rabbit b ay 25c. $1. ; bots a ‘ <- Poultry Rg DE Bat coe : nple

FOR MEN AND WOMEN

MEN or bi ee ng oy Profits Selling Guaremsend Free ee nw = * ue al ‘or etree a uo % Dept. H0e, Attics New York” @ —

wos a a ag pag opportunity. good pay, travel. te C. T. Ludwig, 424 Westover Bldg,, Kansas City,

GENUINE Inhdian Dames —Wnoleanis. Gilham, Highland Spring,. Californ’ ee. “SEXUAL Philoso * 12c. Clear, ific, authori- a tisfies. Fred B. Ka

tative, comopléte essmann, Lawrence, Massach a ee ee annem. gotsinoting work. Ex ce un ulars Write. American etective System, 1 Broadway, New York. SEX books for advancei adult penieate and fessionals. The most authoritative e books including Kisch, Forel, Krafft-Ebing, etc. Send for list. Modern” Book Socie ty, 5 Hanson Place, Brooklyn, New York City, Desk 16.

MR. ADVERTISER: Ask to-day for a copy of the Be ayn Advertising Rate Folder.” It contains some real Wy im t facts which = prove interesting and valuable to you. . It also tells * How You an Use Popular Science ~~ gg Aha ee OO You'd like to know, wouldn't Classified’ Advertising Popu Popular Se Science Monthly, “325 West 39th Street, New

SAVE 60% on engraving by using our Non-Plate ving Process. 50 wedding-invitations, engraved, with double envelopes, $6.75. 100 visiting cards engraved, ja post; . Office statio: , bus! announcements, Samples and prices furn upon request. Alden Non-Piate pam Company, 15 Avon Street, Boston, Massachusetts

wm i The world's most te ag set of keys. Master Ss. Comenny, 34 Manhattan Building, Milwaukee, AVOID Income Tax Worry and confusio! Use Ley’s Ready Records duri HR aes $1.50 Complete. Copper Journal, Hancock, Mi ELECTRICAL Langa, aay Machine, $3, and $7. Catalogue for stamps. J. H. Temke, 1019 he * Psm., Cincinnati, Ohio. a mapa Indian's recipe for growing hair; tonishing Proof box mailed for 10 cents. ‘John Hart Brittain, 50 East 32nd Street, BA-118, New York. DID You Ever Lose Your Keys? Found yourself in- convenienced didn’t you? Su Supply yourself with a Devil's Combination Master .Key,.w y actual test has opened hundreds of locks, and will prove very Fae in ah-emer-

ency. By mail, + ad Urich Key Company, Dept. B, ilwaukee, W: MANSFIELD'S “automa Water god has made fortunes for man y make Send for pememers to win Mansneld. 7 od Victoria Road, New righton, England. IMMUNITY from infection. Use L-Wood Sanitary cov for closet seats. Package containing 6, 15c so .- L-Wood, 460 Madison Avenue, Albany, New ork.

PILES—For the latest scientific treatment write Elite eae. * cana 1004 Lawler Avenue, Auston, Chicago,

a ay a penne ggg G. B B. Pract ob Ms Madison Street, Cortland, New York. PR haf i! ates Bg + a oes Washington, D. C.

50,000 4-page, 6x9 circulars, Warren's Paper, $135.00. Other fh aa proportionate. Times Printery, St. Francis-_

ADVERTISING SERVICE

ADVERTISING prepared and placed — pd Letters, circulars, booklets written, ifustrated and e Doug las Wakefield .Coutlee, 1A West -34 th seen New MEN—Get Vital Strength. Retain youthful vier. Wonderful results Intensely interesting booklet free. The A. Gyde Company, Washington, D. C.

DOGS, BIRDS, PETS

READ the Rabbit Journal, St. Francis, Wisconsin. Two years, $1. Trial Subscription 25c. FERRETS all kinds, price list free Glendale Ferret Company, Wellington, Ohio. me Collies and old English shepherd dogs. ~— ages. Rabbits, nm gs thoroughbred stock. Send 10c [ list of what you want. W.R. Watson, Box 225, Oakland, Iowa.

e EDUCATIONAL AND INSTRUCTION

SR ARSOA. Drawing mnty taught by mail. Fifty cents each lesson. Pay as you learn. No = er ex- pense. mplete drawing cuttit, valued at $20. with the course. One hundred genuine blueprint , B.. send for full particulars and sample lessons. Albany a nal ga echanical Drawing, Dept. ‘‘A,”” Box 84, Albany, LINCOLN-JEFFERSON University, Home Study in College, Theological, Law, Music, Pharmacy, ee and ———_ Schools, Leading to degrees. Lock B x 239G, cago Banos increased. ~ Learn Berling’s mathematical syste ce $1.00. Box 635, Indianapolis.

1,000 Advertising Headlines and Showcard Suggestions. Inspiration for advertisers. Mailed on receipt of 50c. ——— back if you return book. Richards School of Advertising, 4305 Cottage ‘Grove. Chicago. SPECIAL! Inch display advertisement 150 magazines thrice $15. Globe Syndicate, Atlantic City. ADVE TISE in 24 big Iowa dailies, 25 words $10.00: “They Pu Advertisers Guide, free. Union Advertising, Baltimore Building, Chicago. RICHARDSON'S Agency writes sane, sensible advertis- ing. Folder free. Evanston, Illinois.

GLASS SIGNS for rooms, furnished rooms, boarding, dress-making, cafes, restaurants, banks, . offices, door name plates, house numbers, glass signs made to order. Write “or x list. Penn Glass Sign Company, Fort a rkansas.

LLS Water, liquids, = drinking purposes—half Bs, hour. $15 — European Supply, Box 1682, ttsburgh, Pennsy POULTRY Feeder, New Fig ages No waste. Sanitary. hia and Mash Form L. Kelly, Saranac,

—— keys 50c. Open over wwe hundred locks. Used J Shestivet, <a estate, mbers. Cn7 four tt ange Eo dreds. , Loc mith, Box 2 Wolf Point, FB BARD WOOD -SLOORS —-. en Tenevaee —_ & re- oe own floors. Instructions and formulas tell w, also care of floors. Price $1.00. Post Office Box 775B, Cnicago. Illinois.

TELEGRAPHY

TELEGRAPHY (both Morse and Wireless) and ~ egg 4 Accounting taught quickly. Tremendous demand. salaries. Great opportun: ties. Oldest and aay ee m.. A established 46 years. All expenses a . Dodge's Institute, K Street, Vale

ADDING MACHINES

MARVELOUS new Automatic — Machine. Re- tails $12.50. Work equals $300 machine. Five-year-guar- antee. Write for trial offer. Calculator Corporation, Dept. P, Grand Rapids. Michigan. THE SESAME adds to 9,999,999. 25c. B10. Tay- lors Falls, Minnesota.

STAMMERING

dnt a 28 My simple and nateres Method will correct your impediments. Instruction individual. Samuel E. Robbins. 246 Huntington A venue, Boston. ST-TUT-T-T-TERING and Stammering cured at home. Instructive booklet free. Walter McDonnell, 59 Potomac Bank Building, Washington, D. C.

INVENTIONS FOR SALE om nar. PING tool for binding wire onto hose. Most samt eo on the market for the proces. Write for description. and model, b field. Sell cheap. Wm. 8. Houghton, Mi MR. ADVERTISER: Ask toda lor a copy of the Ha eg ae ae Rate F Ln * It contains ocmee spely. ime facts which will ag J interesting and valuable 7s + ly. Proatab ay tt ve ou Can Use a onthl wouldn't quidn't. you? | M ork. 10

“West 39th street,

i

18 WORDS in 100 Magazines, $1.00. Lists Free. Stan- ford Corporation, Lancaster, Pennsylvania. 1000 CO-PUBLISHERS wanted! Terms—Registration, $3. Globe Syndicate. Atlantic City. SALES Problems Solved. Complete facilities for marketing your article at a = Evans & Dubes, Fairbanks Building, Springfield, Ohio. we CONCORDIA Magazine, rly, 2D Water Street, York, Pennsylvania. Advert: rates 4 cents a word, four times 12 cents a word. TO reach.the best paid workers in Michigan in Grand

Rapids, Saginaw, Muskegon and Battle Creek try the list Samet by "the Michigan Associated Labor Press. One cent a w cash. One and one-half cent if charged. Cc. O. Taylor, 61 Market Avenue, Grand Rapids, Michigan.

LETTER SPECIALISTS

THE Secret of Writing Successful Letters revealed to you by Ad-Man Davison, the highest-paid letter writer in the world. Wonderful 976-page instruction course, including 500 successful letters. For Free Booklet address Desk 60, Opportunity Press, 681 Fifth Avenue, New York.

MAILING LISTS

NEW List. Guaranteed. $1.75 per 1000. Drake, Hitchcock, Oklahoma. DON’T miss this offer! You get new business, quick cash ae using fresh names mail order buyers, Pes pene September, 1920, farmers, rural folk, 2500, $5. trial 300, $1. a, 1, Martinek 10 Company, 405 Avenue, New Y

OFFICE AND FACTORY EQUIPMENT

sealing Machines Bought Soig aia Revue, Guaranteed achines ug! Omice Device Company, 154A, West Randolph, Ghicago” MULTIGRAPHS, Addressograp!'*, Duplicators, Sealers, Folders, less than half price. Guaranteed one year. Pruitt ADDRESSOGRAPHS, Multigraphs, Duplicators, Fold- ers, Sealers, ht. Sold with Guarantee. Office Device Exchanee. $03 Baltimore Building, ehicago. *

TYPEWRITERS AND SUPPLIES

MANUFACTURED typewriters at reduced Shitued. for 5 days’ . Write for our Catalog No. 25 and save money. Company, 58 West Wash- ington Street, Chicago.

FOREIGN LANGUAGE STUDY

ee ANISH tical individual aes y correspondence, $7. 00 onthly. re fe 1.2 Seadte, 180 Broadway, New York. (Established Quick-Action Advertisements continued on ae 12

MAKE Big Money. Earn $10 to $25 daily. Be a show card writer. Fascinati profession. Enormous demand for window, show and advertising cards and signs. Won- derful course of instruction shows how to become expert. Given FREE to those who buy our assortment of Nobema Art Colors. Write at once for details of remarkable offer. ee , aeameeel Corporation, Dept. 2, Pleasantville, ew Yor SPANISH—Spontaneous Method. You and I exchange letter in Spanish every day. Inexpensive, Particulars free. Guillermo Hedin, 3509 Franklin Avenue, St. Louis, Missouri.

PICTURES AND POSTCARDS

SPECIAL—Twenty clever, classy, assorted postcards ee meeoeke. Swanson, 1205S Kansas Avenue, Kansas y, Kansas EVERYTHING in itcards. Live-wire list free. Worth-while samples 2 Mention Cn ne to aterves. Mutual Supply Company, Bradford, Pennsylvan JOIN Live Postcard Club. Membership ace 10c. Harvey Teeple, Decatur, Indiana. JOIN the Western Post Card Club. P. Hunan. Man- ager, Elk, Washington. MR. ADVERTISER: Ask to-day for a y of the “Quick-Action Advertising Rate Fo der It contains some really important facts which will prove in teresting and valuable to you. It also tells * ‘How You Can Use Popular Science Monthly Profitab a You'd like to know, wouldn’t you? Manager Classified Advertising, Popular Science Monthly, 228 West 39th Street, New

PATENTS FOR SALE

PATENTS on two small metal novelties, for juvenile use, for sale. Alfred Plauschinat, 1725 North 19th Street, Philadelphia, Pennsylvania. PATENT 1297399, wish market or sale same outright. George Pratt, Box 1700, Richmond, Virginia. FOR SALE—Patent outright or royalty, Automobile Fender; new safety device to protect lives. : itkenfeld, 1823 Bergen Street, Brooklyn, New York. WE have a few practical money-mak in ventions = sale or trade. Adam Fisher Mfg. Co., 183B, St. Louis,

GAMES AND ENTERTAINMENT

FOUR Magic Catalogs and Samples—l5c. Gilmagico, Morgan Park, Illinois. CHALK TALK, Illustrated in colors. Fine rag pictures. Lecture for pictures. Price eens 00. R. H. Johnson, 4514 South 20th Street, Omaha, Nebraska

POR ig Catal . Magicraft Ce E., Box Oost, Detratt, Salhi, ae ia Jokes, Books, Pictures Big catalog for stamp. United Sales Co., Springfield, Fiilinoie

TRICKS, Feetes, zeabea Plays, Wigs, Mind Reading Acts and Sensational Send ‘stens me & catalogue. = Magical Company, eet. 400, Oskhosh. Wisconsin. AMES, puzzles, magic wicks, F peste. Thadaene free. Pastime Circle St. Louis, Missouri 125 CARD Tricks, and how to do them. 25c. United Sales Co., Springfield, Illinois.

Qo fh = ws ww AF ce loc no alt the tw eas | ae an pla tha tho on anc wal

Page 137

December, 1920 Why Live An Inferior Life? ‘Your Success Guaranteed A Subtle Principle of Success HIS SUBTLE PRINCIPLE in my hands, without education, without cap- -- ital, without training, without experience, and without study or waste of time and without health, vitality or will power has given me the power to earn more than a million dollars without selling merchandise, stocks, bonds, books, drugs, appliances or any material thing of any character. This subtle and basic principle of suc- cess 7 ires no will power, no exercise, no strength, no energy, no study, no writing, no dieting, no concentration and no conscious deep breathing. There is nothing to prac- tice, nothing to study and nothing to sell. This subtle and basic principle of suc- cess does not require that you practice economy or keep records, or memorize or’ learn to_do anything, or force yourself into any action or invest in any stocks, bonds, books, or merchandise. This Subtle Principle must not be con- fused with memory systems, ‘‘will power” systems, Christian Science, psychology, magnetism, thrift or economy, nor should it be confused with health systems, auto suggestion, concentration, ‘‘personality,” self-confidence or opportunity, nor should this Subtle Principle be confused with ini- tiative, mental endurance, luck, chance, self-analysis or self-control. Neither should this principle be confused with imagination, enthusiasm, persuasion, force or persistence, nor with the art or science of talking or salesmanship, or advertising. No one has yet succeeded in gaining suceess without it. No one has ever succeeded in failing with it. It is absolutely the master key to suc- cess, prosperity and supremacy. When I was eighteen years of age, it looked to. me as though I had absolutely no chance to succeed. Fifteen months altogether in common public school was the extent of my education. I had no ‘money. When my father died, he left me twenty dollars and fifty cents, and I was earning hardly enough to keep myself alive. I had no friends for I was a negative and of no advantage to any one. I had no plan of life to help me solve any problem. In fact, I did not know enough to know that life is and was a real problem, even though I had an ‘‘acute problem of life” on.my. hands. I was blue and despondent and thoughts of eternal misery arose in my mind constantly. I was a living and walking worry machine. I was tired, nervous, restless. I could not sleep. I could not digest without dis- tress....1 had.no power of-application. Noth- ing appealed to me. ‘Nothing appeared worth doing from the fear that I could not do anything because of my poor equipment of mind and body. J felt that I was’ shut out of the world of suc- cess and. I lived in a world of failure. I was such a pauper in spirit that I blindly depended on drugs and’ doctors for my health, as my father before me. I was a “floater’”” and depended on luck for success. The result of this attitude on my part was greater weakness, sickness, failure and misery as is always the case under similar conditions. Gradually my condition became worse. I reached a degree of misery that seemed intolerable. I reached a crisis in my realization of my failure and adverse condition. Out of this misery and failure and pau- perism of spirit—out of this distress— arose’ within’ me a desperate reaction—'‘a final effort to live’’—and_ through. this reaction, arose within me, the discovery. of the laws and principles of life, evolution, . personality, mind, health, success and supremacy.. out of this:misery arose within me the discov ery of the inevitable laws and principles and sickness and inferiority. Also- failure.

When I discovered that I had uncon- sciously been employing the principles of failure and sickness, I immediately began to-use the principles of success and supremacy. My life underwent an almost immediate change. I overcame illness through health, weakness through power, inferior evolution by superior evolution, failure by success, and converted pauperism into supremacy. ‘

I discovered a principle which I observed that all successful personalities employ either consciously or uncounsciously. I also discovered a principle of evolution and be- lieved that if I used it, that my conditions would change, for, I had but one disease— failure, and therefore there was but one cure —success, and I began to use this principle and out of its use arose my ambition, my powers, my education, my health, my success and my supremacy, etc., etc. You may also use this principle of suc- cess deliberately, purposefully, con- sciously and profitably. Just as there is a principle of darkness, there is also a principle of failure, ill health, weakness and negativeness. If you use the principle of failure consciously or unconsciously, you are sure always to be a failure. Why seek success and supremacy through blindly seeking to find your path through the maze of difficulties? Why not open your ‘‘mental eyes’’ through the use of this subtle success principle, and thus deliberately and purposefully and consciously and success- fully advance in the direction of supremacy and away from failure and adversity? I discovered this subtle principle—this key to success—through misery and neces- sity. You need never be miserable to have the benefit of this subtle principle. You may use this success principle just as suc- cessful individuals of all time, of all countries, of all races, and of all religions have used it either consciously or unconsciously,:and as I am using it consciously and. purposefully. It requires no education, no preparation, no pre- liminary knowledge. Any one can use it. Any one can harness, employ and capitalize it, and thus put it to work for success and supremacy. Regardless of what kind of success you desire, this subtle principle is.the key that ‘opens the avenue to what you want. It was used by Clemenceau, Mozart, Marshall Field, Mendelssohn, Sarah Bernhardt, Copernicus,

,

I = Galli-Curci, Confucius, Nordica, Mohammed, Melba, Cicero, Cleopatra Demosthenes, Alexander Aristotle, the Great, Plutarch ison, Christopher Newton, Columbus, Wanamaker, Vanderbilt, Phil Armour, Marcus Aurelius, Andrew Carnegie, Pericles, Frick, Lycurgus, Elbert Hubbard, Benjamin Shakespeare, Fraoklin George Washington;

and thousands and thousands of: others—the names .of successful men-and women.-of-aH times and> of all countries and of all religions, and of all colors, make a record of the action of this Subtle Principle oi Success. None of these individuals could ‘have succeeded without it—no one can succeed without it—no one can fail with it. f Every one realizes that human_ beings owe a duty to each other. Only the very lowest type of human being--is--selfish to the degree of wishing to profit. without helping .someéone. else... .This ‘world . does: not contain very: great numbers’ of: the: lowest and most selfish type of human beings. Almost ef VYIL WG DOE BE TS 7 Se. ot 8* mit 11

everyone, in discovering something of value, also wants his fellowman to profit through his discovery. This is precisely my attitude. I feel that I should be neglecting my most im- portant duty towards my fellow human beings, if I did not make every effort—every decent and honest effort—to induce everyone to also benefit to a maximum extent through the auto- matic use of this subtle principle. I fully realize that it is human nature to have less confidence in this Principle because I am putting it in the hands of thousands of individuals, but I cannot help the negative impression I thus possibly create. I must fullfll my duty.to each member of humanity just the same. < I do not urge anyone to procure it because | offer it without any obligation whatsoever. I urge everyone to procure the Subtle Principle of. Suecess because the results it holds in store for each indi- vidual are great—very great. This subtle principle is so absolutely powerful and overmastering in its influence for good, profit, prosperity and success, that it would be a sin if I —— to myself and used it only for my personal enefit. So sure am I of the truth of my statements— so absolutely positive am I of the correctness of my assumption and so absolutely certain am.I that this Principle in your hands will work wonders for you— that I am willing to place this Subtle Principle of Success in your hands, at my expense, without-any obligation whatsoever, on your part. You will recog- nize the tremendous value of this Principle within less than thirty minutes—in fact, almost immediately, as you become conscious of it, you will realize its prac- ticability, its potency, its basic reality and its power and usability for your personal profit, pleasure, ad- vancement, prosperity, success and supremacy. Thousands of individuals claim that the Subtle Principle of Success is worth a thousand dollars of anyone’s money. Some have written that they would not take a million dollars for it. You will wonder that I do not charge a thousand dollars for the Subtle Principle of Success—for discl osing this Principle— after you get it into your possession and realize its tremendous power and influence for your success and supremacy. I, myself, have derived such tremendous results —amazing results—from its po wer, that I want every man and woman to have this key to success, prosper- ity, wealth and supremacy. T his is why I am willing to send it to any one—to any address, without any obligation whatsoever—this Subtle Principle of Success is yours to keep, yours to use for the attain- ment of your success, happiness and supremacy. Remember you are under no obligation what- soever, to pay or to return anything to me. The Subtle Principle of Success is yours to keep. You would never forgive me, and I could never forgive myself, nor could the creative forces of the Universe forgive us, if I failed to bring you to the point of using this subtle principle of success. You would never forgive me if I failed to do for you that which you would do for me, if our positions were reversed.

You want success of some kind. This is your op- portunity to get it—to get what you want. Write your address on the form below, or write me a postal or a letter, asking me to send you the Subtle Principle of Success without any obligation of any kind whatsoever, on your part,and you will re- ceive by return mail:the Subtle. Principle of Success —a Principle of supremacy—the key to your every success—the equal of which you have never seen. ALOIS P. SWOBODA, 814 Berkeley Bidg., West 44th Street, New York City te Ne Say RN SUN RR SR ee eR Ee ALOIS P. SWOBODA, 814 Berkeley Building, West 44th Street, New York City You may send me at your risk and expense, the Subtle Principle of Success. F promise you and myself to help myself to the utmost through the Subtle Principle of Success. promise to-accept the Subtle Principle-of Success with an eager and open mind for my gdvantage: I am above seventeen years of age and I am sincere and honest in my statements and promises. It is u tood- that-1 am not obligated to return or to pay for the Subtle Principle of Success. PD i 6c eannebwd ccticcsecogmatevadwenes evant (write plainly) Address.........0+2eeeeseneeereeeteene Peer CMF cicig c nvpe cece scccvcnnnty vc cagesgds ecievis pss tp.see Raa Ts, . ich ate @ Ob Cee cee San «ele aie Note—The above statement in Popular Science Montht is absolutely guaranteed in every way to be as vopeenemted.

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PHOTOGRAPHY AND SUPPLIES Quick-Action Advertisements continued from page 10 REAL ESTATE—FARM LANDS

MAIL us 20c with aay ¢ size film for Covciaperens, and six velvet prints. Or send six negatives any size and 20c for — % grits. Or send 40c for one 8x1G mounted qoianlee pt perfect service. Compang, 212 Bell Avenue, Roanoke, Virginia. FILMS, developed Se roll, prints 3e each. Photo Ser- vice, 929 McMillan, Cincinnati, Ohio. DISABLED Soldiers Photo Compan pany. 3654 North Halsted Street, ~. Films A aan c. Trial prints

MR. ADVERTISER: Ask to-da' & copy of the eS Action Advertising Rate older. It contains 2 Aye yay facts which will prove interesting :. ., 183 A, St. Louis, Missouri.

THE G. = 2 Manufact no. Special Ma 717 1 Svpemere Street, Cincinnati, Ohio. yo Models, Patterns , Tools, Metal Star Contract Siadewaten. INVENTORS: Complete service for commercializing eet oe ay. Benjamin Jonap, Marion Building, Vv!

PATENT ATTORNEYS

PATENTS. If you have an invention which you wish to patent you can write fully and freely to Munn & Co., for advice in regard to the best way of obtaining tection. *Please send sketches or a model of — inven’ and a description of the device, explaining its o) tion. All communications are strictly confidential. ur vast nee. extending over a of seventy years, enables us in many cases to ad in regard to ——w without any expense to the client. Our handbook Patents is sent free on a This — our methods, terms, etc., in Oo Patents, ho. ale arks, Foreign Patents, etc., fentine American” tains Patent Office Notes. Decisions sof linterest, 19 investors —and particulars of recen' tented inven Munn & Co., Solicitors of aT Pantene 624 Woolworth Bi Building, New York, and 625 F Street, Washington 0, Illinois; Street, San

obart cisco, California. ATENTS—Herbert Jenner, Patent At porary and wR onal as 622 F Street, Washington, D. C. I report if a patent can be had and its exact cost. Send for circular.

PATENTS, trade-mark, co 4.954 Charges v reasonable. Metzger, ~ Washington, D “— PATENTS Prom tly procured— eee d service. Frighest. ret . -. Moderate fees. efficient < sketch panna for aotianl search and advice. of Patent Law, 38-M Loan & Trust Building. Washington, D. C.

ees tan rotate it trade mar 2 — efor the prot — experiencei, prompt service for ae pswbestian and development of your ideas. Prelim! ~advice gladly furnishei without charge. Booklet =| min ~ Ey fovon ak i ‘Ov ay os ashington, "D. C., “a 22762 wen or Woolworth Building, New Yor “EXPERT Personal Patent See Write for instructive pooases “Patent Protection.”’ Lloyd W. Patch, Washington,

AGENTS AND SALESMEN WANTED

TAILORING Agents Wanted—Big complete sam outfit and case, A omg J 200 large cloth nn 3-price lists and needed re canvassing, or use tn store, free to top Mt $25.00 to $50.00 8 week: may make more. Wri to-day for free elegant outfit to Olesale special offer on a suit for y f and full Sornntien: See our won- a : = " everything years. very garment made measure—ev guaranteed and at itny prepaid. _ Just send a American Woolen Mills Company, Dept. 1407, Chicago. gee Tyres, gs ae ie g potenti b ven an pa Sag outs; double mileage of an: Liberal Details free. Acceasories profits. American co ‘Dept. 97, Cincinnati, Ohio.

AGENTS —Seaty in come. ie. manufacturer of Handkerchiefs and Dress Goods, etc., wishes representative in each locality. Factory to consumer. Bi profits, honest : Be. spare time. Credit given. Send for New York. M fg. Co., 24 Main Street, Brooklyn, ORR TS ake $50 weekly taking orders for a selling Goodyear raincoats; hundreds of orders wai dt gt. E time; ‘we deliver and collect; sample coat : ency. oeeereys. Mig. Com- pany, Tsa7 Ge Gosdyenr untaing. Kansas City, Missourt. EN ising Signe, cpa werywher ae oe be ev le l= mond Co., Buffalo, New Y ‘3 f

“WRITERS: Stores, poems, wanted for publication. see 2 ss ee ipa ene Ine especially for inventors and authors. Yor, $100 Copy, 10c. sockinns, South Dakota. F 12

.

PATENTS—Send for free book.- Contains valuable in- Send | of your Be for Free 7 == its Datentable nature & Tal ree ears ce. bert. bert, 462d 4624 bert Building, Washington, D. C. Quick Action Advertisements continued on page 14

SELL World's Greatest Auto Invention; no more storm blurred windshields; gh Felt works wonders; one rub keeps clear 24 mountings: fits ; whirlwind seller at $1.00; 00; Vetter made $75 first ty Mfg. Co., Dept. 306, Toledo, O}

--- me om at). Sat’ ob tat Ot ee Af. te Bete 4

Page 139

—- = weet ve t Veer & oer ‘.“show you’’ basis. “fore you pay me a cent. December,.1920 tea _Five Days to Prove ty uw WU se I Can Raise Your Pay I’ve done it for thousands of others. do it for you. MEAN just what I say. There’s no trick or catch about it. Give me five days and I'll prove that I can get your pay raised for you. I'll do it ona You get the proof be- You've. probably heard of me. My name is Pelton. Lots of people call me ‘‘The Man Who Makes Men Rich.” I don’t deny it. I’ve done it for thousands of people—lifted them up from poverty to riches. There’s no sound reason why I cannot do it for you. So let’s try. Now, follow me carefully. I’m going to tell you exactly how to do it. I’m the possessor of a “‘secret’’ for which men have been searching since Time began. There’s no need to discuss the whys and the wherefores of this “‘secret.’’ Suffice it to say that Jt Works. That’s all we care about—IJt ‘Works. Over 400,000 men and women the world over have proved it for themselves. Among them are such men as Judge Ben B. Lindsay; A FEW EXAMPLES Personal Experiences Among over 400,000 users 3 of Will” are such men a6 Judge ey Supreme a reme Ie Parker; Wa Tiss Fang, Ex- J ustice ar er ~ U.S. Chinese Ambassador; | Goy. McKelvie, Assistant Postmaster Gen- eral Britt; Gov. oa of Nebraska; Ge ral Man- tice mol fa Welle. ee — Co.; E. St. Elmo Lew of Detroit; Gov. Sart, "of Michigan; and many others of equal of Nebraska; Wu Ting Fang, Ex-U. S. Chinese Am- bassador; Gov- wer: prominence. ernor - Ferris, of $300 Profit. frem One Tichi . Dire Wcding _Michigan; and ‘thousands of others of equal prominence. Some of the things this “secret” has done for people are astounding. I would hardly be- lieve them if I hadn’t seen them with my own eyes. Adding ten, twen- _ ty, thirty or forty dollars a week to a man’s income is a-mere nothing. “The result from _one day's study netted me $300 cash, I think it a great book and would not be without it for ten times the. cost.’’—Col. A. W. lke, Roscoe, So. “Dakota. Worth $15,000 and More “The book has been worth ..more than. $15,000 to me,” —Oscar E. Sheppard. Would be Worth $100,000 “If I had only had it when I was 20 , ears old, I would be worth $100,000 to-day. It is worth a hundred times _ the price.’-—S. W. Taylor, F med Santa Fe Ry., Milans, ‘ex. - From $100 ~ $3,000 a Month “One of our boxe who read Power of Will elore he ‘came over here jumped f $100 onth to [- ’ $3,000 the first month, the That s merely won rize pad the . Ben “aleamamahip fe th playing at it.. Lis te.”—Private Les! his :, Still A. E. F., France. gtd A young” matin - as I’m willing to tell’-you the * I can doubtless If I can’t then it won't cost you a cent the East had an article for which there was a nation-wide demand. For twelve years he ‘‘puttered around” with it—barely eking outa living. Today this young man is worth $200,000. He is building a $25,000 home—and paying cash for it. He has three automobiles. His children go to private schools. He goes hunting, fishing, traveling, whenever the mood strikes him. His incomeisovera thousand dollarsa week. In a little town in New York lives a man who two years ago was pitied by all who knew him. From the time he was 14 he had worked and slaved—and at sixty he was looked upon as a failure. Without work, in debt to his charitable friends, with an invalid-son to support, the out- look was pitchy black. Then he learned the “secret.” In two weeks he was in business for himself. In three months his plant was working night and day to fill orders. During 1916 the profits: were $20,000. During 1917 the profits ran close to $40,000. And this genial 64-year- young man is enjoying pleasures and com- forts he little dreamed would ever be his. I could tell you thousands of similar in- stances. But there’s no need to do this “secret” itself. Then you can put’it to-work and see what it will:do for you. I don’t claim I can make you rich over night. Maybe I can—maybe I can’t. Sometimes I have failures—every one has. But I do claim that I can help 90 out of every 100 people if they will let me. The point of it all, my friend, is that you are using only about one-tenth of that wonderful brain of yours. -That’s why you haven’t won greater success. Throw the unused nine-tenths of your brain into action and you'll be amazed at the almost instantaneous results. The Will is the motive power: of the brain. Without a highly trained, inflex- ible will, a man has about as much chance of attaining success in life as a railway engine has of crossing the continent with- out steam. The biggest ideas have no value without will-power to ‘‘put them ‘over.’’ Yet the will, altho heretofore en- tirely neglected, can be trained into:won- ‘derful power like the brain or memory and by-the very same sae aes s @x- €rcise and”use., eres: a “ 4 y aeane Oo ens Siies poth@etrast A ocr fowl ‘ profit on a $4.00-sale. _-Name., 2S. re If you held your arm in a sling for two years; it would become powerless to lift a feather, from lack of-use.- The -same is true of the Will—it becomes useless from lack of practice. Because we don’t use our Wills—because we continually bow to circumstance—we become unable to assert ourselves. What our wills need is practice. Develop your. will-power and money will flow in on you. Rich opportunities will open up for you. Driving energy you never , dreamed you had will manifest itself. You will thrill with a new power—power that nothing can resist. You'll have an influ- ence over people that you never thought possible. Success—in whatever form you want it—will come as easy as failure came before. And those are only a few of the things the “‘secret’’ will do for you. The secret is fully explained in the won- derful book ‘‘Power of Will.” How You Can Prove This at My Expense I know you'll think that I’ve claimed a lot. Per- haps you think there must be a catch somewhere. But here is my offer. - You can easily" make thousands— you can’t lose a penny. ‘ Send no money—no, not a cent. . Merely clip the coupon and mail it tome. By return mail. you'll receive, not a pamphlet, but the whole “‘secret”’ told in this wonderful book, ‘‘POWER — OF WILL.” Keep it five days. Look. it. over in your home. Apply some of its simple teachings. If it doesn’t show you how you can increase your income many times over—just as ‘it has for thousands of others—mail the book back. You will be out nothing. But if you do feel that “POWER OF WILL" will do for you what it has done for over 400,000 others—if you feel as they do that it’s the next greatest book to the Bible—send me only $4.00 and you and I'll be square. If you pass this offer by, I'll be out only the small But you—you may easily be out the difference between what you're mak- ing now and an income several times as great. So you sag you've a lot—a whole lot—more to lose than I Mail the coupon or write a letter now—you may never read this offer again. Pelton Publishing Company 14-W Wilcox Block Meriden, Conn. Se A SNS EEE EE EL CRN SINCE RN RRS RR NS NR PELTON PUBLISHING COMPANY, 14-W Wilcox Block, Meriden, Conn. You may send me “Power of Will’’ at your risk. I agree to remit $4.00 or remail the book to you in five days.

Page 140

AGENTS—Make a dollar — hour. Sell Mendets, a — patch for tree. Collet ~s leaks in all utensils. lette Mfg. Company, Dept. package 467, ya —-4 New $40 to $100 a week. Free samples. Gold let any one can put on windows. Big demand. beral to general agents. Metallic Letter Company, 431A North Clark, Chicago. AGENTS —Gomething nt Our Eradium (Lumi- nous) Crustiix, ac ~~ f shines the dark... Startling! Mysterious! Wonderfu Enthusiasts follows every demon- stration. 150% profit on every sale. Sole manufacturers. i Ser poration, i263 West 63rd Street, Chicago, inois. MEN and Women—Become independent—own your business, experience fee my selling our.$6,000 Acci- dental Death, $30.00 Accident, $25.00 Sick W 'y Benefits, Guaranteed steady in- $10.50 yearly, amounts $5.50. come from renew: $250,000 deposited = en "De partment. Registration Dept. 8. =. N.J VULCANIZING Auto , ane promis business jally new. book i. lants le jaa] $50 up MGatalog ‘tree Company, 149 Canal. Cincinnati, O 0. SALESMEN wanted to sell Electric Cigar Lighters and Moisteners. Salary or Commission. You carry stock or we ship direct. Write for Special Offer. Drake Manufacturing Company, 220 Grand, Milwaukee, Wis- consin. HAVING sold re gd of a household appliance in New England a Sa seprensntetizes, we wish District Man anegers to > open open other territory. ome work. a side tory assignments Paying upw $5000.00 yearly. Reeves Company, 51 Broad “Boece Milford, Connesileut. AGENTS and General hy py traveling a profit instead of a loss. Go from i A town selling household necessities and securing n ke Write. Big income on your own and tary agents’ work. rite quick. Duo Company, Dept. B16, Attica, New Yor THE PROSPEROUS Agent is a Davis Agent. Line u for the b' ee yo seek I Yigg oreh 50% d 200% for you. Davis Products Co. Meee. Bl 51, Chicago. BIG Money and Fast Sales. Initials for his auto. You.charge $1. Ten orders daily easy. Write for_particu free Dept. 47, samples. American Monogram Company, East Orange. New Jersey AGENTS make 500% profit handling auto mono- grams, new patriotic pictures, window letters, transfer flags and d novelty signs. Catalog free. Hinton Com: mpany, Star City, Indiana. MAN in each town to refinish chandeliers, brass bem, automobiles, by new method. $10 daily without capi or experience. Write Gunmetal Company, Avenue Decatur. Illinois. PATENTS. Write for Free Illustrated Guide Book. ce Med stanton Rew natere est references. omp Victor J. Evans & Co., 174 Ninth, ee ington. D ‘ SALESMEN, high grade, for state and county ae cies; practical device rings electric bells forever yithout batteries; made by a manufacturer. — e a pon rl es idl, po Rm «5 -—! and previous terr! r ly ass experience easential. Betts & Betts Corporation, Betts Building, 42nd Street, New York. AGENTS: rofits. Best and cheapest window letters made. Easily ~ Ay Dime br five samples. Particulars free te Company, 1115 nd Avenue, New York. SIGN Agents to represent us in your locality: unlimited field. Samples free. Interstate Sign Company, Dept. A, 2620 North Halstead Street, Chicago. aa gage a A or traveling. necessary. for list of lines and Tall fence un- particulars. Prepare in 8) wn to earn the big salaries—$2,500 to $10, "100 a@ year. Employment services rendered members. National en's Training Association, Dept. 1268S, Chicago, [linois. AGENTS: _ Sell rich looking 36x38 tngarted $1.00 each. Carter, Tenn., sold 115 in 4 days; —_ t $57. You can do same. tite for sample os — — plan; exclusive _— Sample rug by i post prepaid, |$ $1.39. * Condon, importer. 12 pharl 1 Street, $5.00 Daily a Fates Puddings, ree, te eee, Tae Articles, e Sample free. ‘“Taymor,” 115th Street, yew York. KEROSENE Burners for Furnaces, Cook and Heating —— Economy Mfg. Company, 616 West Monroe, cago GET our plan for monogramming automobiles, trucks, hand ianeeas and all similar articles by transfer method; canarias unnecessary; exceptional somes. Motorists, Accessories Company, Mansfield, an = WHISKEY, Brandy, Rum, ne, Wines, 50 Other Non-Alcoholic Flavors for Sods t untain, foods. etc. Out-selling all others on the market. One salesman’ sold over a thousand dollars worth in one week. Write a" for particulars and proof. Make these —F Ry. get Ccotusive now. Crouch, Che Broad- way, New York. 500 AGENTS wanted at.once for Mitchell's Magic Mar- vel Washing Com: % profit; enormous repeater. Washes clothes ies _spotlessly clean ae —— fifteen minutes. One thousand a Astounds and delights every woman. Nothing else like it. Nature's q Se py EA no wa, see acid, or wax. tee the sale f Seman on a pon Aen f guaran 0! a4 xclusi ve Own your own business fou oom cannot fail to make b' money. Baker. — made Lag a last a, x for free sample and p roof. Hurry, ‘hi Ff is chance. Le Mitchell & Company, Desk’ 301, 13 iia) East 61st, Shicago pe ee of spices, bg finest toilet soa persone, toilet an» Sheokutely free_to pond our refund .» Dept. 615, St. Lou Missourl, AGENTS wanted for automobile alties, three big sellers, patented, big profit. no competition, every owner a prompenk, Rubber S Grips, Lu ig Lamp Brack- ets and others. Fracto alty , Mantitacturers, 161 Massachusetts Avenue, Boston, usetts MR. ADVERTISER: Ask to-day for a a a of the Rn ye Advertising Rate Folder Saf c — and id. valuable to you. It also tells “* How You Cah Use Science aay 2 Profitably. S ge Fs like to wouldn't you? Advertising, Popular Science ae... 225 West son Street, New ‘Quick. Action Advertisements cantinued on page 16 Quick-Action Advertisements continued from page 12 ONE sale a day means $200 per month. Five a day— $1,000 per mon elous new Automatic Adding Machine, equals $300 ——. Five-year guarantee. Write quick for protected terri and tfial offer. Calculator Corporation, Dept. 0, Grand ichigan. Popular Science Monthly AGENTS make big money because sales may be made in ps pane. Our modern aids to home sanitation have an appeal cannot be resisted. A brush, mop or duster oa ka Liberal commissions and "good territory. scge Brush Company, 136 Clark Street, Free- es | EASY, pleasant work vf mocenie. shop men, clerks, during spare hours, pay qotare to their ge Also want time. Big w: assured. ovelty “Gatiory give full 27 Bar Street, Canton, Ohio. : AGENTS—Best seller; Jem Rubber Repair for tires one tubes; supersedes vu ag ge at a savi = over per cent; put it on cold nizes itself in two minu’ and is guaran to a the life of os aa “4 tube; sells to every auto owner and dealer. sabia Saat OS SOOT neue ells mazon Ru * D Philadelphia: Pennsylvania. E $30.00 next opis. Speederator for ceiling ik Tike wildfire. Used b: Moto cials. Makes ord run like a Packard. Stops yt a bucking. Put on on quick—instant satisfaction. Sell.ten to twelve a “day >... 2 profits and exclusive. territory. Write uick Yor ormation. Address ee in Company, 1072 Soyeuse Building, Detroit, SALESMEN—Side or main line, to sell Lowsericed 6, pan for Sihene —_ Po a gen tires, 30x3 non-ski on : other proportion. -ma! agit for live wie Master Tire Co., mongy=m aking qicbigan, Chicago. AGENTS, big prone selling famous Keen-O Polish and Rug. Cleaner. thing new, som les and particulars 350° Keen-O Polish Company, 1 Avenue, Ke- nosha, Wisconsin. BIG PROFITS selling auto owner needs them. trouble. Exclusive territory. Company, 14 Station C, Omaha, SIGNS for stores and offices. Entirel easily made. Chicago Sign System. T: a River Bireet Chicago. g : 26 River Stréet, “FLOWER ER Pood Necklaces” fast every state. Los tH ts AGENTS: Sell our accident and sickness policies in your $5000 death, a? weekly benefit. Pre- n t sellers, want agents ood Bead Comoe. 230 East 30th Street, Dept. 5-6. Newark, New Jersey. DON'T read this unless you want a Bee proposition. Combination Fn and Clutch Pencil case, heavy metal, each wi co peeket oe clip. Big joke and for actual Sells at sight for $ nd for ee, Agent’ 8 — Ay me or more 35c os elt profit. sam) and agency. Ash Novelty ompany, Tot Xenia Avenue, Dayton, Ohio. WA made entirely of heavy copper, on - Prices $30 OO and - pegs “ey respectively. express apt e same day we -. Ideal for vaigtiling water for automobile uses and drink References: reets, mana, f Boyer & Co., Omaha, Nebraska. SELL poo les. Everybody and -buys the “Business Guide.” Bryant cleared ‘Sooo in July. Send oor sam le, Its tree. ichols Company, Box 1B, Naper- ville, Thin é GET our plan for games 4 Spon Ry = at home. No canvassing. Quality eq ~ at “- Lo rice business—quality profits. doing 3 A ne | ae rae Company, 1212 Spon Building, Elkhart, : EASY .Oilers for. Ford .Engines Deaters and’ Agents. Sam & ‘Company, Woodward Building, Washington, D. C. FOOLPROOF paint-varnish remover, money back few York. Martinek 10 Company, 405 Lexington Avenue, pen: get into the wonderful tailoring agency business, bis pee rofits taking orders and your-own clothes free. We ¥ fine sample outfit and everything free. No ex- orme7 need rite today. Banner Tailoring Co., t. 754, Chicago. py? mpeplalty. aoe 25c. undreds. Building. yphiadel hia. WORLD'S fastest ogee auto spteeeny! tributors wanted; write y. GL San Diego, California. 350% profit. Klean-Rite Magic Washin: Compound. tiasheo Clothes without grin Sells 25¢, ou make 19¢. Samples free. Bestever Products Company, 253-P, Belleplaine, Chicago. LUMINGOS ee La ae any article visible in the dark. Bottle, 50c. Guaranteed. Sample, particulars for “Red” camp. Illuminant Company, 744LP North Lock- wood, MR. ADVERTISER: Ask to-day for a copy of the PR ag yo Advertising Rate Folder.” It contains some really important facts which = prove interesting and valuable to you. It also tells “ You Can Use Popular Science Monthly Proftably.” You'd like to know. —. ou? -M Classified Advertising, P Popular Se onthly, 225 West 39th Street, New or’ make ‘“‘Easy Money”’ for Universally needed. e $15 daily. 202 Pennsylvania County dis- W. Spring Oiler Co., lence STOCK in pocket, $10.00 profit. Norisk! Don't have to buy. Sample, Quarter. Try it. You ought to! Returned if you don’t ‘olen to try. V. B. Company, Pearl River, New York. WATER STILLS, made ¢ vagy! 4 co ;, two gallon capacity, $25, four lion, 695 3% distilla- tion of all liquids. Gekace given Richard & Company, 200 Broadway, C310, New "York die BIG a ee © oors, Sestres., etc., $1.00 brings ections for making b t. oil varnish at $.75 per gallon. C. Parker, Box ose Beusic Washington. WERE You Ever Offered A G Bried You can Aluminum Ware and poy: ne money age | take large orders and proven quality. are guaranteed Selling ex- perience not poseamnes - we rofitable work for “workers.” Address Hitchcock-Hill mpany, ys 220, Chicago, Illinois. Reference: Any Bank or press mpany. BIGGEST—Best Money Maker Guaranteed—Wonder- ful Proposition. Big Holiday Success. Only Safety Razor Cannot Cut Yourself, $1.00. Standard Safety Razor Corp., Pittsburgh, Pennsylvania. AGENTS to Travel by automobile to introduce our fast selling popular priced household necessities. The greatest line on earth. PMake $10 aday. Complete outfit od automobile furnished btn to workers. rite tony for exclusive territory. merican Products Co., 235 American Bidg., Cincinnath Ohio. MAKE: $50 Daily—Something New—400% By Free Sample. Business, Professional Men re-order Retails $2.00. Your Profit $4.00. Write for State 1 Rights quickly. Headquarters, Drawer 596, Hartford, Connecticut. aaa: We $6 a day taking orders for New erogas “Burner. ts any stove, Burns coaloil. perience or capital required. Work apare ¢ time rite for a ng sample. Thomas Mfg. Co., Class 2661, Dayton, O) { chusetts $1. Write for agency: ‘Magee = ee ae eS ld Ay Boa G necessary. ne Oo orld’s e Grocery houses (c: tal over $1,000,000.00) wants ambitious men in your locality to sell direct’ to consumer nationally known brands of an extensive aes of groceries, paints, roofings, lubricating olls, foods, etc. a on — ee ~ EA ¥ Write unty lesired. John Sexto Sule, Illinois. “LITTLE WONDER” Crown Capping Machines sell to every housewife, equal in comolency” to rs T Power — Fastest sellers. Agents, cke, Dept. F, Alhambra, California. AGENTS Sensational Hit. New Rubberized G Aprons; attractive; Be ea rapid seller; i aberncaly Eyre & Lee, Box 152 Station, Pittsb vania. Dept. 78. today. |, xton & Company, 363° West t linois Stree . $6000.00 A YEAR is your profit from 4 sales a da ;Davia- son sold 96 one week. No superienes needed. Alad- din light is a sensation wherever introduced. 5 times as bright as electric. Won Gold Medal. Farmers have the money. they need this light and 9 out of 10 will buy. ie, Souervamey in small towns and suburbs. Excellent evening seller. No Capital Required. A, = -¥-x trial. Write for agency proposition while territory stl = — Mantle Lamp Company, 524 Aladdin $15.00 DAILY —_ 2 the New Amberoid Unbreakable Combs; kind you can hit with a hammer; write for whole- ale prices J. Bucknam, Box 2792, Boston, Massa- AGENTS wanted to sell the famous “‘Flexedge’’ engine valves that are guaranteed not to pit, warp, leak, crack or need regrinding. Automobile owners buy them readily ——— and are . Ca financial investment. They are grein: ment by prominent ae of automobiles and y buildcrs of oil burning e es. attractive proposition awaits your request. 8. . Ve Co. 706 Townsend Street, Chicago. AGENTS: Something brand new. ‘“‘Liongrip”’ Safety for a. All families want them. 10c brings seine. A. iggins Mfg. Company, Bar Harbor, Main MEN and women agents wanted to sell a household article which is far superior to similar and extensively advertised devices. It sells easily at tS -50, costs 75c. Our agents sell 15 to 30 a day ann $10.00 to 320. 00 a day. Good article for crew manag Ladies can easily sell to neighbors and friends. mend. 75¢ for a sample prepaid. Free catalog of other dent sellers. Ls popnanes Sot to establish — ent permanent Foz business Lafayette Brush Mfg. Company, 1034 Rising Sun Avenue, Philadelphia, Pennsylvania. ay Spark ee od Transformer. All Cars. More Less Gas. Large Profits. Get our prices. pred. s ‘Manufacturing Company, 2246 North Central Park, Chicago. R. ADVERTISER: Ask to-day for for a copy of the sqeek- Anion Advertising Rate Folder.” It contains some really im You Use A You'd like to Classified Advertising, “West 39th Street, New know ? Popular Science Monthly, 22 AGENTS! Side-line ween! ange is the fastest selling novelty ever prod Perfect qometoune pocket =. and clear lighter. * Sells to cigar, drug, sta- tionery, novelty, mags punch board trade, etc. Send $5.40 for samp le a Money back guarantee. The Art Metal Works, Dept. S., Newark, New Jersey. I WANT 100 men and women quick to take orders for Comer —— and waterproof aprons. Every’ y buys. McCrary’s profits last year were $5,218. ‘New vies wonderful pargains—direct from manufacturer to wearer. — made $523 in thirty days. Tremendous profits or you. $2,500 a year for three average orders a day. $10a a A for your spare time. No Celiv Pad collecting. No capital oo nay furnish qvere® oe ge = a yay coat. Write quick for lib off: Com Dept. 0-41, Dayton, Ohio. AGENTS wanted to sell our.25 light acetylene gas gen- erator; fully guaranteed; cheap; safe and reliable. rite Daniel Zimmerman, Magley, Indiana. HELP WANTED DETECTIVES earn big money. Great demand. Travel. Experience unnecessary. We train you. Particulars free. va se. American Detective System, 1968 Broadway, New BE a ee travel. Write C City, Missouri. STOP daily grind. Start silvering mirrors. Auto head- lights, tableware. Plans free. Clarence Sprinkle, Dept. 95, Marion, Indiana. GET on the St I tell you how! Send stam yo Stage Book and particulars. A. La Delle, Angeles, California. BE a Mirror. Expert, $3-$10 a day; spare time home at- first; no capital; we train, start you making ang sil- ing. mirrors, French method. Free - pros us. Derr, Pres., 579 Decatur Street, Brooklyn, Zz. FIREMEN, ee. Baggagemen, $560-9000. Colored Porters, railroads everywhere Experience unnecessary, 830 Ratlway Bureau, East St. Louis, illinois. MEN—Age 17 to 45. agg od wes oi Travel, make secret investigations, reports. Salaries, expenses. American Foreign Detective Agency, 321, St. Louis. Excellent o rtunity, good pay, T. Ludwig, 424 estover Bldg., Kansas for in- x 557,

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December, 1920: Secrets of Selling that Make These Men 10000 aYear Star Salesmen Some Amazing Stories of Quick Success T is hard to believe that a man who has been working for years in a routine job at small pay could almost over-night step into the $10,000 ..a year class. Yet that is just what many men have done and are doing today. That such big success could come-so quickly and so easily seems almost incredible. If I should tell you that one man who had been a fireman on a railroad stepped from his old job to one that paid him $10,000 a year, you would be inclined to doubt the truth of my statement. But I can show you the man’s own story. And ‘that is only one instance. I can show you many more. And perhaps the most surprising part of it all is that these men were just average men. They came from all walks of life, from all fields of work. They had previously been clerks, bookkeepers, mechanics, farm hands! Some of them had never earned more than $60 a month—some of them had .drudged for years at. dull, uninteresting work with- out prospects of anything better in life. And then, in one quick jump, they found themselves earning “more money than they had ever thought. possible. Suddenly all their dreams of success, position, and financial independence came true. The Secret of Their Success What was responsible for their remarkable rise to the ranks of the big money makers? What did they do to lift themselves out of the low pay rut and step to magnificent earnings? The answer is very simple. These men decided to get intothe great field of Selling—they learned about Send Me Your Name I have shown hundreds of men how to step from small-pay jobs into the bi money class in one quick jump. $10,000 a year—yes, and more—has come to men as a result of writing tome. Just let me send you the whole amazing proof— entirely free of cost or obligation—J. E. Greenslade, President, N.S. T. A. how to become Star Salesmen and fitting them into positions as City and Traveling Salesmen. Through its help hundreds of men have been able to realize their dreams of big opportunity, success, wealth and independence. Men without previous experience or special qualifications have learned the secrets of selling that make Star Salesmen —for Salesmen are not ‘‘born’’ but made, and any man can easily master the principles of Salesmanship through the wonderful system of the National Sales- men’s Training Association. Anyone who is inclined to doubt that this is so has only to read the stories of men who tell in their own words what the Associa- tion has done for them. Here are just a few examples: J. P. Overstreet of Dallas, Texas, who was formerly on the Capitol Police Force of Washington, D. C.., states: ‘‘My earnings for March were over $1,000 and over $1,800 for the last six weeks, while last week my earnings were $356. The N.S. T. A. dug me out of the rut where I was earning less than $1,000 a year and showed me how to make a success.” C. W. Campbell, of Greensburg, Pa., writes: ““My earnings for the past thirty days are $1,562 and I won Second Prize in March, although I only worked two weeks during that month.” What These Men Have Done You Can Do It will not ‘cost you a penny to learn how you, too, can become a Star Salesman and take your place among the big money makers of business. Whatever your ambition may be—$5,000, $10,000 or more a year— find out about your great opportunity in the wonderful profession of Salesmanship. See how the N.S. T. A. can open to you the way to a big selling job, to the wonderful opportunities in this fascinating pro- fession—why salesmen are always in demand—why they receivesomuch more money than men in other ‘fields of work. And they became Star Salesmen! Probably if you had told any one of these men that it was possible for him to become a Star Salesman he would have laughed at the idea. If ‘you had told him that it was not only possible, but that it could be done in his spare moments at home, without interfering with his work, he would have dismissed your statement as being too absurd to be even considered. For you must ‘remember that most of those men had never had a day’s experience in Selling —they had no special qualifications for Salesmanship—no thought of ever becoming Salesmen. What Makes a $10,000 a Year ~ Star Salesman? As a matter of fact, these men who are today reaping-such handsome rewards as Star Salesmen, would probably be working still as clerks, book- keepers, mechanics, etc., if they had not learned about the National Salesmen’s Training Associa- tion’s. system -of Salesmanship Training and Free Employment Service. This is an organiza- . tion .of top-notch Salesmen and Sales Managers formed just for the purpose of showing men Into the Big Pay Class in One Jump! Earned $524 in Two- Weeks ps had never earned more than $60 a nth. Last week I cleared $306 and thie: week $218. we have done wonders for me.—Geo. earns. 09 W. Pa Place, ew aay City, O I Now Earn as High as $100 a Day I took your course two years ago. Was earning $15 a week clerking. Am now selling many of the largest firms in the U.S. I have earned more than $100 te ‘a day. You secured me my position. Our Sales Manager isa grad- uate of yours.—J. L. DeBonis, 1628 S, Crawford Ave., Chicago, Ill. Earned $1,800 in Six Weeks As soon as I received a letter’ from you and your literature, I knew that I was on the right track, and very soon after I anatber fora position as a Sales- man to one of the firms whom you in- formed me were in need of a Salesman and to whom you had recommended me. My earnings for March were over $1,000 and over $1,800 for the last six weeks, while last week my: earnings were $356. The N.S.T.A. dug me out of a rut where I was earning less than $1,000 a year and showed me how to makea success.—J. P. Overstreet; Dallas, Tex. prosperity and a life of fascinating work, travel, contact with influential men. Just mail the coupon or write, and you will receive, without cost or obligation, proof of what the remarkable sys- tem of the National Salesmen’s Training Associa- tion and its FREE EMPLOYMENT SERVICE can do for ‘you. “In addition a great book on Salesmanship will be mailed to you without charge, You owe it to yourself to read of the quick and brilliant success that others have achieved and of the opportunities that await you in the field of Selling. Mail the coupon or write today. National Salesmen’s Training Association, Dept. 15-W Chicago, Ill., U. S. A. me —— Sebnemeel wee _— Ronamemell Sener tented — —— — -_ National Salesmen’s oS a jation, Dept. 15-W, Chicago, Ill., Send me Free Proof that you can make-me a Star Salesman and tell me how you will help me land a selling job. Also list showing lines of business with openings for Salesmen. This does not obligate me in any way. PRUE ne Oops wcnehsegenesasseeteseons Mr « eth ee we BE May WO Hier iV; oa PPR Ay. 91.635 Bi cia es een ose

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100,000 High-Salaried Men Needed! (os es e in a new uncrowded ‘or your trained services? ment olan you a field filledwith —— nities now easy for you to grasp. Never has such a chance come to ~ and it ma ear come again. 100,000 high-salaried Traffic men are-needed at once, to handle efficiently the tremendous amount of traffic which is crowding the railroads and steamship comperion, to ca- pacity. $3,000. to $5,000 a year is gladly paid. And now comes to you the opportunity to quickly obtain one of these fine traffic positions. Exchange Your Spare Time For A Big Traffic Job Now through the American A iati you receive the help of many of America’s greatest managers in preparing for this fascinating of the need for traffic these f. experts of the Association's staff are eager to put you on their list to be trained for one of big positions open. shippers and ship owners are literally crying for trafic men. Y6u don't have to quit your present job in order to prepare for one of these positions. Such men as T. Albert G Gantt, Traffic Manager, Corn Products Refining Company: William Scott Cowie, American Freight Board a i G. Lutz, Vice President, Chicago & Alton R. oc nearly 200 others of equal prominence train nt quickly and thoroughly in your spare time ‘ale @ cost so trifling that any ambitious man can easily take advantage of this great opportunity Traffic Men Earn Big Money Because They Save Their Firms Big Money It is easy to understand why traffic men are in such need and why they receive such big salaries. A traffic man recently saved his concern $24,000 on shipments to their new plant in Chattanooga. Another saved $9,751 in shipping 66 carloads in two weeks. Another saved his firm $36,000 by applying ee apa rate on 1,500 cars from Pittsburgh to Traffic Experts saved an automobile concern .000 in ten — A traffic expert discovered that freight rates paid by the Meeker Coal C were legal,..but Pace ey A ruling secured from the Interstate Commission resulted in a refund of $122,000. » An‘oilshipper in Kansas was losing over $30 every day—$799 monthly—because he = not =, .of certain mre vee regulations entitling him to tes. ———- Is it any wonder that the traffic experts who can save. their e and ¢ doliare in freight wthmas are highly paid? Such knowledge can almost dictate its own salary, MAIL COUPON FOR FREE BOOK “Swap” your spare time for a big traffic job: Mail coupon now*for — book. Explains why firms all over th d traffic men to handle thes. ship dhipping and traffic problems economi- cally-a: Yently. Gives full Tateraiities. about opportifities open to you and how you can earn $5,000 a year sod more ia this interesting profession. This free book* open your eyes to & new, un- crowded Drofession = tee eager ~ wd trained services as to pay you big | mood or Coupon “today.” i "ASSOCIATION Chicago, Ill.

Dept. 14iz, abe American Commerce Association, Dept. 1412, 4043 Drexel Blvd., Chicago, Ill. Please cond me nen obligation, your new book, “A New. Profession."" and tell me how I can qualify for Traffic Management.

Add.

en

; ¥ 1 i. aA

5

Quick-Action Advertisements continued from page 14 Sens wanges. 1 want 0 few mate man so tain 28 nD poor dd. Leet month and more. Big demand. Splendid Learn quickly at home, Let me send you Lesson. Address: les M. Director, “chicago. Technical Building, ‘Ga , , SILVERING mirrors, French te taught... Easy to immense proses. — Kage 3 irror Works,

RAILWAY traffic tampesters earn from $110 to $200 per month and ex vel if desired. Unlimited ad- vancement. © age limit. We co you. Positions fur- guarantee. for Booklet Ou -18, Standard Business Training Inetitate Buffalo, New Yor! tentable ature free. Sélid sketch for free opinion yt — & Talbert, 4846 Talbert Build: = an an Expert Penma device guides corrects your writing in few Gaye. Complete Saving Free, Write Mr. Ozment, 52, St. Louis, Missou MEN- wanted for Detective Work. Write J Ganor, Former arama Detective 115, St. Louis, Fae WRITE Paetogions: $50 eath. Experience unneces- ary; V free to beginners. Producers’ League. 194,

BIG demand ser for graduate electrical ickly under Electrical Engineer. orough y Methods. Small Expense. Albert Wood Wicks, E-E. Dept. 1777, 431 South Dearborn Street, Chicago. BE A DETECTIVE—Big Pay; nice work; write Wagner, 186 East 79th, New York, Dept. 226. into - went tailoring agency business, % fo ere and your own elothes tree We te today. Banner T Teltering oi Co. Cards and S'

wri ence needed. 55, Chicago.

WaNzeD at once, Show Writers or those with artistic taste eas and make — at home or travel “Miller, 2050 msterdam Avenue, New York.

BUSINESS OPPORTUNITIES

“PATENTS—Book free. Send sketch for free opinion

tentable nature. Talbert & Talbert, 4847 Tal et balla. , Washington, = = 100 FIN beautifully beep mnccrae Saale GB aeee ball leveland Ohio. : “SUBSTANTIAL manufact ition wants le men to am ee branch and manage salesmen. to $2000 necessary. Will allow expenses to itimore Bal as caplned, Address Mr. Clemmer, 603 N. Eutaw S&t., Baltimore, Md. me Big Money making-marble, onyx,-agate, tile, etc., ore beau Rifak and less than one-tenth cost of genuine. Marble and other fancy face brick, $15 thousand sell for $75. Cost of Ly | reduced 25 ttle capital to start. Money-back ae tee ii in 1 with “4nstructions, Send for list of products and sample. years ey P. ‘O. Box 213, Los Angeles, California. ARE you satisfied with the success you in the past? If — ve our am eo 5 Seemee and positive that Sur 5.0 220.00 with its money mak —,. Bn pede to y~ 00 annual premium accident pore sold to men and.women—16 same rate. Million h American ‘0 °308 sox cera Walnut surest sFaseiiete Fe —— vania.

Registered A oe Pree 5 fervce for fhe pro- or, Booklet of or ~~ 4, Owen Buildi hard B. Owen, 44 ate anon DO. or 2276-Z Woolworth Building, New — EXPERT Chemist will furnidh Formula and Trade Secrets in all lini Lists free. L. Cummings, Ph.D., Gordon Avenue, “Syracuse. New aS VULCANIZING ame Tires growing and profitable Instruction qpecety Be to learn. - Book $1. lants $50 uD. free. Equipment Cstalogue Company, 151 Canal Street, Cixcinnati, Ohio. BE a detective. Excellent o porvunif travel. Write C. T. Ludwig, 424 City, Mo. DOLLARS i a in your backyard. No mushroom See. - Particulars Metz, 313 East, 89th, New ork.

> good pay, dg., Kansas

Details free. American Automobile Acces” sories Co., Dept. — Cincinnati, Ohio. “ep | Property, Farm Con 1838D StL ts_| 60 Agents wanted. ra Established 35

Popular Science Monthly tn EEE 9 pow busines. Barn $3,000 *, 58, 008 voarty in professional fees making specialty; everywhere with EY gt can mn attend oo: ensey S aaeaee by or at liga a ye = to buy, ob I ating, soll soleiting of agency. 5 idress ‘Step en- son Laboratory, 15 Back Bay, Bos 2 usetts.

WE start in busi furnishing hing. Men and women, $30.00 to $100.00 | soe Rd xy o perating our “New en Coote Candy Factories here portunit letime. Booklet tree. H. Ragsdale Compa pany, East Orange, New Jersey. $3,000 fo $10; $10, O00 a of tate ~ {introduce wag -“c b sete. Sales cam: campaign ' tree to je qualified. 1 Few Gollere al makes big, quick money. FireX Company,

— and. practical in veltions. Trade Sell ee rights. 1 Pn Louis, M ‘ DON’T miss this offer! ~ You affor new Salieen. quick _ cash returns, using fresh names m pn gh buyers, Ecomplied led * printed ae 1920, al f trial 300, 00. Martinek 10 Gompany, 405 Toeteaien Avenue, Fw Yor! MEN. on into ~~" bap - | tottering gency Ags 4 Po fine sample outa —_ = ver free. N Write hs H Srerything tree. ee vo expert

ence needed. $56. Chicag: seaneis and Heating Men thinking of going into business for themselves soon, can hasten that time by at once to Niebuhrs” Plumbers Business Bureau 105 Street, La Crosse, Wisconsin, Se regarding financing

for confidential ounting, estima

START A Lucrative Business Your Own. Wi teach you how to establish successful col. eon anfor you. no . Walter 4,523 .43 ‘as sends wa rm statement showing earnings of .$8,039.0 for March. O. H. Overholser, net commissions 1.51 net. Such tart now in spare — Pointers,” an where 4, seo others a have. —. “Pointers,” w plan. merican lec- tion servios 7 7 State ‘street, ‘Detroit, Michigan. EACH $4 for material makes $75; then each $75 makes $1,400. Easy to start this — new chemical business. 20,000,000 for steady customers. STEWART, 1106 Empire Building, Birminghst, Alabama. START a cleaning, dyeing, and pressing a - your own home. Taree promis. Details free. A. A. Barnes, x5m; Helena, Ar SEND. for free ye “How to Succeed in Real Estate Business State occupation. Mac onald Cooperative Realty Company, San Diego, California. DRT RInC TORS. and poe be you want to handle _a real, liv Then write at once and secure the: ‘local sales rizats tor ‘pened Steel Auto Lugs. They are almost a necessity where bad roads are found. A driver having a set of thes2 lugs need never fear the — kind of road. Simply attach to rear wheels and away go. Can apply in less than a minute. Takes any —— ile or truck out of mud, holes or ditches. Retails for $8.00 a set of four. Handsome commissions to dealers. an oppor- tunity to make a lot of mone (It’s some satisfaction to always have traction.) Samp! e set will be furnished if de- sired at retail price. Address World-Over Sales Company, 505 Fifth Avenue, New York City. * MAIL Order ‘Business +" your. opportunity, Breniser’s Famous Handbooks.teach how .to‘start.small, grow big. Sell merchandise, service ideas; ~enormous profits. Spare time to. begin. Be gomplote set,.11‘books $2.5 337 M.. Walnut, Street, Philadelphia. riptive eatalogue and b and big baton’ interest’ ting mail order information 25c.

- “STAMPS” AND COINS

51 = stam) also ‘packet & unused, gem ship set, 2 scar “Sige nites berge - 81: 3. 8S. revenue, Derforation gauge and price lists. All for 9c. ecu ~ Fennell Stamp Co., Dept. C., Fullerton Bidg., Be Louis, “Migsouri. , 270% $% size, “Normap

wOALIEORNIA bold. quarter - size, 53c. cent logue 10c._.. Shultz, King pit - Be Finest. Approval ae 50% to

pany, Dept. 55, St. Lou

MAN ‘or Woman, materials that, cost equipment. Call or” or Ey for Aimed Anderson: 3: Vulcanizer Company, 2302 Grand Avenue, Kansas City, MR. BUSINESS MAN—would you Uke ou like to. be repre-

pag hh yd FE DS ‘k Office Sa ohne then ie thie cages ti meee or am a eee erences with order to M. Ellis, 1 0 Riverside Avenue, Newark, New Jersey. USED Corres den Courses all oe 801d. (Courses bought. Tee Mountain, *Piscah, Ala’

FOR sale—old established mall order meaut ing business. For particulars address Pioneer nuraciring Racine, Wisconsin.

INVENTORS—My clients know ag step taken = prosecu' their ap) Plications. Bookle' . bee ob ‘arner berley, 20 ‘National Union Blag., juest.» Washington, D.C ““NEW Goods, Mail Order and Agents Samples 15¢c; Catalog 2c. 2c. Harvey Teeple, Decatur, Indiana.

STAMPS, 20 All Different, 3° cents. _. Mention paper. Quaker Stamp Co., Toledo. Ohio. $2 to $600 paid for hundreds of old cies dated before 1895. Send 10 cents at once for new illustrated coin value book. Size 4x7. It-may mean ad fortune. Clarke & Co., Coin Dealers, Box 76, LeRoy, 17 varieties Bulgaria stam low priced stamps free. Nassau Street, New York City. - STAMPS—50 varieties, Transvaal, ‘Brazil, Peru, Ome. Mexico, etc., and Album 10c. 50 différent U. 8. 1,000 hinges, 12c. 1,000 mixed, 40c. List free ¥ stamps. C. Stegman, 5949 Cote Brillianter Si St. Louis,

'20c. List of 7,000 varieties hambers Stamp Co., 111C,

“STAMPS—0 different British Guiana, China, Jamaica, Pi Venezuela, ones 10c; 1,000 all different, fine collection in itself, $5.00 ‘ep we U. S., 30c; 1,000 hinges, 10c. Agents wanted. vist free. I buy stamps. L..B. Dover, Longmont, Ga jorado.

paid. Swanson Bros. 500 Pee No La La Salle St., Chicago. tg mir inky peftablo Busine. “Wei iweits

ORT card Stree faising — avaee. zea et ei Ge ie ver, Wisconsin. ERE ee -¥ 16

: — | A — 60 all feces. ~ 3 ge ag A 7 E $30 a week evenings @ small ma collectors ‘an pe toe. Mo weden mps posta, Pree DE ws Booklet tells how. 2c postage. Al me eee Wy ‘oledo Stamp Company, Toledo, Cohoes, New iy hs Ohio, U.S.A. . WENTIETH Century Book of Recipes, Fonkans OL! coins, e Tall eelling catalogue of coins for od - contains 0,000 items tems ‘covering a broad list | sale, -free: Gatalofte quoting ing prices id for coins, ten of sub It is a money pa ay too, for many o the cents: - William 101-A Tremont Street, Boston, formulas < d° aes made ~~ foundation for a F omall b Massachusetts. ness at h bound. - Price, $4, pos 19 DIFFERENT pretty, unused French manials, 10c. Nickles, es Florida Avenue, Washington, D

x P Collector's Album, spaces for a Zz 106 afta aig et starhps—1000 peelable hinges. Millim page catal of packets and sets. ont these salah’ =: for 50c. ware hie L. Crinns, 930 West Onondaga Street, Syracuse, New York. 100 stam . 10 different French-Colonies 10c. Lists R Buckéy, 712-A Bowen, Dayton, Obio.

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December, 1920 Let these fifteen world- famous auto engineers help you intoa big paying job. They can doit. The Library of Automobile Engineering written by these men will tell you everything you need know to earn $50.00 to $100.00 a week or more in the auto game. Start right now. More men are needed—thou- sands of men are needed to keep the country’s eight million cars in good going condition. Over 75,000 sets of these great books have been sold on our no-money-down-easy-payment-plan. See our free offer below. AutttoBooks 6 Volumes SENT FREE No matter if you don’t know a thing about automobiles now, you can learn the auto game backward and forward with these books to help you. They explain everything. They turn every make of car inside out—show you how it is made—how to repair it—how to keep it in good con- . dition—how to go into the garage business for yourself. 6 big books bound in flexible American morocco contain- ing 2600 pages of money-making facts and more than 2000 pictures, blueprints and diagrams, Anyone who can read can understand them. Send NoMoney You don’t have to pay one cent in advance. Just mail the coupon and use the books for a whole week in your home or shop—then decide whether you want to keep them or not. If you like the books, send us only $2.80 in seven days and $3.00 each month until $29.80 is paid. If you don’t like them, just ship them back at our expense and you won’t owe us acent. Along with each set goes FREE a membership in this society, worth $12.00. Mail the coupon now, before the membership is filled. ® Thec is all ed. Se i. 2 Mail Coupon Now the Sooke tans , eden anye 7 — “ Learn All About Automobile Motors —Welding— Motor Construction —Re- pair—Carburetors and Settings— Valves—Cooling— Lubrication — Fly- Wheels— Clutches — Transmission— Final Drive—Steer- ing— Frames— Tires—Vulcanizing — Ignition —Start- ing—Lighting— Shop Kinks—Gar- age Design and Equipment—Elec- trics—StorageBat- teries—Care and Repair of Motor- cycles and Trucks — Gasoline Trac- tors and How to Repair Them. 128 Buetrie "Wiring enema Diagrams 4. thing. This is our guarantee that you will be satisfied. There is no risk on your part. Mail the coupon ERICAN » . ne Ae . ide to ’ h Dept. olume wiiect If 1 decide th the $29.80 . Auto th ect. Please S¢ dime a month ut examina ey: ithin 7 da wit e Reference «++ ring for mobile Engineer al think Ica onl return the! a

Page 144

$2,500 to $5,000 a Year Earn big pay and win swift promotion! Get out of the rut and qualify for a real, big pay job! Be an Electrical Signal Engineer. Op- ge =e 5 in this big, new field are unlimited. work is simple and easy to master—we teach you at home in Tw spare time. FREE if it You het Mout A complete drafting set with special drawing instruments, triangles, curves, etc.—als0, com- plete signal outfit with model miniature rail- .2 > in 32 LDSOres St No need of from one to four years to me a master ectrician. You get intensive, individual and practical instruction in res ed ae Bi ad od Electrical Experts Earn Big Pay Greatest demand for trained Electricians in America’s history ht now. Other trades taught too in the aT COYNE TRADE SCHOOL. o"Hrafting, EB iotion Picture Operating — all in short ane. unde: experts. Many stadents. earn money while learning. be ny i tw de ‘ pelt he —_ — ie unity. Opportunity

Begin mabe 0 ee pore for My FREEB BOOK fee ay at home dur- ings 38 Fo BGO ys

2 stamp to Day postage. F. W. Tambiya,” = Ridge Bldg., Kansas City, U.S.A. STAMMERING Complete and permanent cure effected at Bogue Institute. Aninstitution wit ith national patronage, forstammerers —v; Founded 1901. Scientific treatment—combines eegaen TY] brain with speech organs. th ful endorsed by me profession. 70 page book with ful -foallstammerers. Address BENJAMIN N. BOGUE, President -673 Bogue Building, Indianapolis, Ind.

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a at your fingers ends Know the facts in Electricity. They mean more money and better position for you. Hawkins Guides tell you all you need to know about Electricity. Every important electrical subject covered so you can understand it. Easy to study and apply. . A come plete, practical working course, in 10 volumes. ks are pocket size; leather covers. Order a set toe H Al look over. WKINS GUIDES HA PAGES $1 A VOLUME 4700 PICTURES $1 A MONTH These books tell you all about Magnetism — Induction — Experiments— Dynamos— Electric Machinery — Motors— Armatures— Armature Windings—Installing of Dynamos—Elcctrical Instru- ment Testing—Practical Management of Dynamos and Motors—Distribution Systems—Wizing—Wiring Dia- gra ign Flashers—Storage Batteries—Principles of Alternating Currents and Altcrnators—Alternating Current’ Motors—Transformers—Converters—Rectifi- ers—Alternating Current Systems—Circuit Breakers —Measuring Instruments—Switch Boards—Wiring— Power Li Telephone—Telegraph— Wireless— Bells— Lighting— Railways. Also many Modern Practical Applications of Electricity and Ready Reference Index of the 10 numbers, Shipped to You FREE o until you see ee the books. ligatiom tojpuyrusiees you are satisfied. aie —and get this great help lib and see if it is not worth th #00, 00,to you—you pay $1.00 a mont for ten months or return

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——, mailed f — Popular Science Monthly pir ‘Earn Your Way Through College Cra here to America’s greatest institution of electrical education where for years ambi- tious men from all over the world have been earning their way while learning. Most of our students earn_their, way by our “Earn. While You Learn” plan. You spend part of your time at the school, = at a good paying electrical position secured for you y our Free Employment Bureau. bd me gg ons intensive xpe

training. You can become an Electrical rt in one year or learn an electrical trade in six months. ELECTRICITY cisco: This.is an electrical age. Billions of dollars are invested in this great industry. Hundreds of thousands of nfen are em- ployed init. But the expansion has been so pe 71; yecent that there exists today a great shortage of TR NED, SKILLED men. Such men can command large no bo in whatever line of electrical work in which they specialize. Get into this great field of work now! There never was a better time. Write Quick for Free Book Mail postal or letter today for full particulars of this great school, how you can come here and secure an electri- cal education while earning your way. See for yourself the wonderful methods of this institution with is years of success behind it—1500 students—hundreds of successful gtaduates. Don’t delay! Make your request today. SCHOOL of ENGINEERING OF MILWAUKEE America’s Greatest Institution of Electrical Education 910-373 Broadway, Milwaukee, Wis. Copy this Sketch and let me see what you can do with it. Many newspaper artiste earning $30. to $125.00 or more per week were trained by m b ag vod “= sonal individu = 4 mail. PICTURE. “CHART make original drawing easy to learn. nd sketch of Uncle Sam with 6c in stamps for sample Picture Chart, list of successful students, examples of their work and evidence of what YOU can accomplish. Please state your age. f Illustrating & Cart ing TheLandonSchool 215; schofeldBldg.Cleveland,O. STAMMER 1 stammer attend no stammering school till you get my large Face book entitled “STAMMERING, Its Origin and The Ad- vanced Natural Method of Cure,” bound in cloth and stamped in Pure gold. Ask for special tuition rate and a FREE copy of “The Natural Speech Magazine.” Largest, best equipped and most successful school in the world for the cure of stammering, stuttering, etc. No sing-song or time beat. Write today. The North-Western School, 2335 Grand Ave.; Milwaukee, Wis: Learn in Spare Time to be a CIVIL ENGINEER Earn $1500 to $5000 Yearly Here’s your big chance te be- come a full mange Civil Engineer! With this set o ks you can fit yourself to make big money, in the greatest outdoor profession gaze onearth! Offer fully explained in Med coupon. Good only within bound- £4 aries of the U. S. and Canada. ? Great Books eS FREE 75c a Week : ou keep them a after ays’ FREE TR _. Nine big leather-bound whens 3900 pages, 534x8 inches; 3000 plates, maps, diagrams, etc. Written by Say ‘8 greatest’ civil engineers. Books tell you ALL ABOUT Surveying; highway con- struction; railway engineering; earth work; spsci- fications; estimating contracts; bridge engineering ; masonry; reinforced concrete; water supply ;

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| December, 1920 “Today I dropped in for a last word with the boys at the office. And as I saw Tom and Dave there at the same old desk it came to me suddenly that they had been there just so the day I came with the firm four years ago. was my first job and I took it as a matter of course. But after a few months I began to realize that [ was nothing but a human machine, doing things that anyone could do, | and that I couldn’t expect to advance that way. “So I had a talk with the manager and I’ll never forget what he said. ‘If you want to get ahead, put in some of your spare time getting special training along the line of your work. We want men who care enough about their | future not only to do their work well but to devote part of their spare time to preparation for advancement.’ | “That very night I wrote to Scranton and a few days later had started studying evenings at home. Why, do you li} know, it gave me a whole new interest in our business? In a few months | was given more important work and | more money. Since then I’ve had three increases, six months ago I was put in charge of my department, and now | my big chance has come—I’m to be manager of our Western branch at $5,000 a year! “Tom and Dave could never see any sense in my studying nights “When I started here I was put at a desk and given certain routine things to do. It | ae ee oes ee cee cee TEAR OU i with business, ‘They had the same chance I had—they could have BOX 7603-B SCRANTON, PA. in the subject, before which I mark X. ELECTRIOAL ENGINEER SALESMANSHIP Electric Lighting and Railways ADVERTISING Electric Wiring Window Trimmer up to one of the best jobs in our business. It just shows what spare ; ia : : | time training Ww ill do. Telegraph Engineer Show Card Writer ! —they said eight hours a day was enough for any man to be bothered INTERN ATIONAL CORRESPONDENCE SCHOOLS | | | | been big men in the firm today, But they stood still while I went —{_ Ezplain, without obligating me, how I can gualify for the posi- foremen, superintendents and engineers; carpenters have become architects and contractors; men and boys have risen from nothing at all to splendid positions of responsibility —because in spare hours at noon and at night they have learned to do some one thing well. If you want to make more money, show your employer you’re trying to be Gas Engine Operating OIVIL ENGINEER Surveying and Mappi ping MINE FOREMAN OR ENGINEER STATIONARY ENGINEER arine Engineer Ship Draftsman ARCHITECT Contractor and Builder . Telephone Work Sign Painter Every day men who have let the International Correspondence Schools help MECHANICAL, ENGINEER Railroad Trainmen i i iti j i Mechanical Draftsman j TIN them are moving up to more responsible positions and bigger salaries. Clerks aes Gon tenes bated | have become advertising, sales and business managers; mechanics have become Toolmaker BUSINESS MANAGEMER? Private Secretary BOOKKEEPER Stenographer and Typist Cert. Public Accountant TRAFFIC MANAGER Railway Accountant Commercial Law GOOD ENGLISH Teacher worth more money. If you want a bigger job, show him you’re willing to Rechihocment Dealieman Gomneten Soe} Suttec toon PLuSmine ane NevTING croMOnIbe OPEmATING PLUMBING AND A A ’ ; ; ‘ : * Sheet Metal Work Auto Repairin | There’s a simple easy way to do it. For 30 years the International Corre- ee ee fact, ee spondence Schools have been training men and women right in their own homes CHEMIST AGRICULTURE JE] French | whenever they had a little time to spare. More than two million have stepped Mathematics Poultry Raising 6) Italian | up in just this way. More than 130,000 are studying now, ‘Ten thousand are Name | starting every month. a a i Can you afford to let another priceless hour pass without finding out what i. } the I. C. S. -_ do for you? Here is all we ask—without cost, without obli- a gating yourself in any way, mark and mail this coupon. — tate “ send to 7-26-10 ——————————— ; ane ee ee Sufernational Correapens Sonoo! "Montreal, Canada

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Popular Science Monthly Let Boss Gloves work with you AKE them your constant companions in all hand work. Boss Work Gloves are a comfortable necessity in dozens of odd jobs about the home. In shop or factory, Boss Gloves protect the hands from dirt, grease, and minor injuries. They are especially valuable to garage men, and all who work around automobiles. Made of the finest quality white canton flannel, Boss Work Gloves are tough enough for the most rugged jobs. Yet, their exceptional flexibility makes delicate work possible. - Sizes for men and women, boys and girls—in ribbed, band and gauntlet wrists. Ask your dealer for them. THE BOSS MEEDY — The world’s favorite THE BOSS XTRA HEVY—The world’s cham- work glove for odd jobs around the pion heavy-weight handwear for rough house and garden, and all light hand- work. Made of the finest grade of extra ‘work. Made of the best quality, me- ° heavy canton flannel. ne Sees eanten Belaeet. THE BOSS WALLOPER—This is the super THE BOSS HEVY — The best bet for all work glove. Strong, flexible and built work that requires a strong, wear re- for rugged work. Made of the high- sisting glove. Made of the very best est quality, heaviest weight canton quality, heavy weight canton flannel. flannel. The Boss line includes highest quality leather-palm, jersey, ticking, and canton flannel gloves and mittens. The Boss Manufacturing Co. Kewanee, IIl. This Trade-mark identifies NZ genuine Boss Work Gloves ee) Trade Mark Be sure it is on every pair you buy a a

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December, 1920 2 ULTONA it 4 PLAYING A BRUNSWICK RECORD iy WITH hd REMOVED TRETONE AMPLIFIER a “ could pa - font than offer a superior phonograph HILE the Brunswick Phonograph has won its great prestige because of its many advancements, it has likewise won its place because of the con- fidence of the people in the House of Brunswick, a concern known for nearly a century in American industry. For such a concern, with its heritage of experience, to produce an ordinary phonograph was unthinkable! In the Brunswick Method of Repro- duction are included some of the epoch- making improvements that have won fresh applause for phonographic music. This method has brought an instrument which the most critical prefer. The Brunswick has taught people that all phono- graphs are not .alike. Tone quality has be- come a new issue. To obtain real and lasting satisfaction, make comparisons. Hear this remarkable Brunswick. Become acquainted with its superior tone and its overwhelming ad- vantages. See if you agree that it brings finer tone. Remember that The Brunswick plays every make of record better. Ask to see how our all-record reproducer, the Ultona, does it. Hear how it brings out every beauty of a record. Visit a Brunswick dealer, ask for a demonstration. Then judge the tone, also the finer cabinet work for which Brunswick has long been fa- maus. Ask al- so tohear Brunswick Records, which can be played on any phono- graph with steel or fibre needle. THE BRUNSWICK-BALKE-COLLENDER COMPANY General Offices: 623-633 S. Wabash Ave., Chicago Branch Houses in Principal Cities of United States, Canadian Distributors; Musical Merchandise Sales Co. Mexico and Canada 719 Wellington St., West, Toronto

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ie "@ o = ae: O Scenario Writing on the Spot f 4 This is how Mr. Van Loan, a lead- ing photo playwright—author of . “The Virgin of Stamboul”’—impro- vises whole scenes when emergency demands quick thinking and while the director awaits the “‘script.’® $50, with carrying case fold it up —Take it with you —Typewrite any. ee little machine ed | have ever seen” ‘nary impetus Corona has given the general CORON The Personal Writing Mac Popular Science Monthly 66 ~__ certainly the Switcel New } Divisi S the story goes, the players ‘‘on location’’ waited while the director telephoned for help; and Van Loan came many miles on a motor cycle, his Corona slung from his shoulder, to re- write the scenes or produce new ones. Later he said to a cameraman: ‘‘Corona is certainly the handiest little machine I have ever seen!’ Thus in unexpected ways is seen the extraordi- practice of typing. It has swept aside limitations : of weight and bulk and made typed corre- be spondence, manuscripts, memoranda and reports universal. Not only can it be used anywhere, but its fifty-dollar price, coupled with its sur- prising scope of operation, has rendered its use as economical as it is satisfactory. Consult Your Telephone Book for Nearest Corona Dealer Built by CORONA TYPEWRITER COMPANY, Inc. GROTON, NEW YORK TRADE MARK 144

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Blue Buckle OveFrAlI/s “Strong -for-Work”’ Switching on the New York Division ofthe Pennsy TRADE MARK UNION MADE eg V.5.Pet.0re NE pair of Blue Buckles will prove they give you more comfort, wear and serv- ice than you ever bought in any overall. Blue Buckle OverAlls and Coats are thor- oughbred quality—from collar to trouser cuff. You can depend on Blue Buckles union workmanship; on the tack stitched pockets and seams to prevent rips and tears; the solid reinforced backband not to give or split; the broad elastic suspenders to stay put. Make Blue Buckles your work-day stand- by. You'll find Blue Buckles the biggest- value-work-rig in America. Ask your dealer for Blue Buckles Jobbers Over All Co., Inc. Lynchburg, Va. Largest manufacturers of overalls in the world

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Wili there be a Victrola in your home this Christmas ? If any one thing more than another can add to the joys of Christmas, it is music—and the Victrola can bring into your home, any music you may wish to hear. The Victrola is the one instrument to which the great- est artists have entrusted their art—an unanswerable acknowledgment of its artistic achievements. Moreover, the Victrola is the only instrument specially made to play the records which these great artists have made. Christmas day and any other day through all the years to come, the best or the newest of all the world’s music may be yours to enjoy. By all means get a Victrola this Christmas, but be sure it is a Victrola and not some other instrument made in imitation. $25 to $1500. Victor dealers everywhere. Victor Talking Machine Company Camden, New Jersey

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