Popular Science Monthly 1921-07: Vol 99 Iss 1

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4. :, Measured for Your ‘by Camera—sSee

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APPLY TODAY FOR THIS PLAN BOOK ~ FREE and look for the Cypress Arrow on every board “RIGHT OFF THE TOP.” THE Woon er, 1 WELL,—WHY SHOULD A GARAGE s BE HOMELY? This one isn’t—(Is it?) The man just driving out (in the picture below) is the owner. He looks well satisfied with the fact that he has enhanced the beauty of his grounds at the same time that he has protected his car. BELOW The picture shows how your garage may look if you will allow us to send you, with our compliments, and with no obligation at all, the Complete Working Drawings (on sheet 24 x 36 inches) including full specifications — enough for any good care penter to build from. Perhaps you enjoy such work yourself. If so, you can’t go wrong. It might even be possible to remodel your present gar- age on these lines. If you do so, of course you will know what kind of lumber to buy. “‘If you build of Cypress you build but once.’? You know “The Wood Eternal’’ is the champion pergola lumber—does not tend to shrink, swell or warp like. so.many woods— takes paint and stain beautifully, but does not need either, except for looks—lasts and lasts and lasts and lasts without them. (See U. S. Govt. Rept., reprinted in full in Vol. 1, Cypress Pocket Library: Just mention that you'd like that book, also—Vol. I). “Pergola-Garage” The Cypress This Pergola-Garage is AN ADDED SUPPLEMENT to the 9th big reprint of VOLUME 28 of that home- lovers’ guide, counselor and impartial friend, the famous Cypress Pocket Library. It’s FREE. Will you write? When planning a Pergola, Mansion, Bungalow or s} ‘With CYPRESS you BUILD BUT ONCE. Let our ““ALL-ROUND HELPS DEPARTMENT” help YOU MORE. Our entire resources are at your service with Reliable Counsel. SOUTHERN CYPRESS MFRS’ N 128 Fl Bal Noy Qa tae NN = INSIST ON TRADE-MARKED CYPRESS @T YOUR LOCAL LUMBER DEALER'S, IF HE HASN'T IT.LET US KNOW, - 2 , ping porch, r b Popular Science Monthly —— Popular Science Monthly JULY, 1921 Volume 99-No. I CONTENTS AERONAUTICS Helping the Aviator to Find Himself How Sandbags Save Aviators’ Lives It Is a Seat and a Parachute FOR THE FARMER Picking Cotton by Machine A Machine for Planting the Small Garden The Tractor as a Stump-Puller One Engine for Cultivating and for Churning. . Clasp the Grafted Bud A City Advertising Idea in the Country Hams Smoked the Modern Way Both a Weeder and a Cultivator Grinding Bone for the Chickens Feeding Hogs by Railroad What the Farmers Are U The Air-Driven Pick Is Fa ommunity Ice Cleaning Stony Land by Machinery..... bones he Long-Armed Lawn- A One-Man Road-Grader HOUSEKEEPING MADE EASY Buy a Cabinet for Your Phonograph....... books Stops Boiling when Coffee Is M Beware of Argentine Ants............ She Boils Potatoes in Her Hat An Electric Stove on a Pedestal Temperature and Time Told Send the Clothes to the City Laundry It Folds Like an U Folding Screen Chair for the Garden Clock Makes Memory Eoeening, Canennenney . te Flowers in Burnt-Out Electric Bulbs 66 When Not Used, This Coat-Peg Hugs the Wall 66 Ribbon Woven by Hand ona Tiny Loom...... 67 Plants Will Flourish Here Coke Deodorizes Your Icebox INDUSTRIAL PROGRESS Kill Molds on Lumber by Steaming Pig Iron Made without a Blast Fugnace 420 Hammer-Blows a Minute How a Repelling Arc Regulates Itself Another Tueuar to Lighten Freight-Yard Work Lifting and Weighing Famther Shipments that Write Their Adventures 4 ee Money Out of the Bamboo Shoot Butting the Coal-Cars They've Found a Use for Old Shells Twisting the Wire’s Tail......... Welding by Machine Seven Thousand Products from Coal Make Your Own Rope Electric Machine for Reseating Boiler-Tubes. . Two and a Half Miles of Rope in This Hoist. . Shifting Belts without Danger Another 100,000 Horsepower from Niagara..... Breaking Up the Cream In Milk Carrying Telephone Wires Leggings to Protect the Foundry Workmen... Putting Tools Where bag 4 Are Needed Electric Lights from the Water System Air- or Steam-Driven Tugger Tubes Cleaned with Bullets Below Is a Man Pushing 100,000 Pounds Artificial Pearls Made in America... How Much Zinc Is There? A A Motor-Driven Grinder Cleans Castings...... (Continued on page 4) Copyright, 1921, 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, 1915, at the Post Office at New York 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. H. J. Fisher, President; R. C. Wilson, Vice-President; O. B. Capen, Secretary and Treasurer. Modern Publishing Company 225 West Thirty-ninth St. New York City

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Popular Science Monthly July, 1921; Volume 99, No. 1 25 Cents a Copy; $3 a Year Published in New York City at 225 West Thirty-ninth Street = Curing Disease with Ultra-Violet Light Rays This treatment is coming widely into use By Philip Schwarzbach IGHT, as a healer of ills, has been fromrheumatism. He wasgivenajob of it, and those who were in any way used by people throughout his- that necessitated his working near an afflicted stayed close to the light; they tory. The early Egyptians and arc light of great intensity. Inashort too were helped. Romans took sun baths when they time his rheumatism disappeared com- It was soon realized that the are were suffering from disease, believing pletely. He told his fellow workmen light was much richer in ultra-violet that it was the heat in the sun- rays than sunlight—but it also light that helped them. Sun baths are still somewhat in vogue, but we know now that their stimulating effect is due to the chemical action of sunlight, not to its heat. White light is a composite. A beam of sunlight, as you know, can be spread out into a spectrum from infra-red to ultra-violet. The infra-red rays are the warm ones; they possess very slight chemical properties. The ultra-violet rays have strong chemical properties. And the ultra-violet rays (rays that cannot be seen) are ultra in this respect. Science has proved that the chemical rays are the ones that cure. Hence it be- hooves sufferers to get as much ultra-violet ray treatment as possible. Why the Sun Will Not Do Will the sun fill the bill? Not very well; its rays must pass £. through{the various gases that | surround the earth, and these | gases tend to absorb the ultra- _ violet rays. Hence, when the rays reach us, their chemical powers are not very strong— except in high altitudes. Artificial light, therefore, has had an injurious effect on the skin. The heat rays in the arc light had to be removed before it could be used intensively. Niels Finsen, one of the pioneers in ultra-violet-ray history, found the way to do this, and made it possible for the arc light to be actually pressed against the skin. Besides helping to cure such systemic diseases as rheumatism and gout, the arc light is very helpful in cases of tuberculosis. It inhibits the growth of tubercle bacilli, even though it does not always cure the patient. The Value of Quartz The arc light, however, is rather out of fashion. to-day. Its place has been taken by the quartz mercury vapor lamp, which is more effective and more economical to operate. Unlike glass, quartz is almost completely transparent to ultra- violet rays, and it can be heated to a very high temperature without danger of injury. The passage of an electric current through mercury vapor gene- rates ultra-violet light. By means of a quartz tube the cavities in the head can be been resorted to for producing » / ‘ penetrated, and internal as well ultra-violet rays of any great . as external treatment can be intensity. The electric arc was Catarrh is a difficult disease to cure; but under ultra- given. The picture on this page the first tried. In connection violet ray treatment the patient improves rapidly. shows a patient receiving ultra- with this an interesting story is Here a physician is administering ultra-violet ray violet ray treatment for catarrh told. There was a certain work- treatment by means of a quartz pencil. The rays have b f t cil old. a chemical effect on the nasal cavity, killing bacteria y means ol a quartz pencil. man who had suffered for years and improving the blood condition Not only is the treatment pain- 15

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Instead of removing diseased tonsils, in many cases ultra-violet ray treat- ment is now given. After a few seconds the disease germs are killed less, but it is not at all dangerous. Results are obtained quickly without any violent reaction. What is the secret of this violet-ray treatment? Why does it help cure all kinds of ailments? The answer that Dr. George W. Crile gives to these questions is that it raises the index of a patient’s metabolic efficiency. Metab- olism is the constant building up and destroying of the cells of the body. The process is continuous, and should occur regularly and equally. The amount of destruction should always equal the amount of rebuilding. When this does not occur, disease of some sort sets in. Take, for example, the disease known as dropsy; it occurs when the body takes in more water than it throws off. Many Diseases Are Cured Ultra-violet rays, as has been men- tioned before, are rich in chemical properties; hence, when they are turned on the body, they agitate the cells. Asa result, the cells regain their metabolic equilibrium and proceed to function properly. And now let us consider the various diseases and ailments that are cured by this treatment. In the first place, ultra-violet light has a very soothing effect on human beings. If you are overworked, worried, nervous, or under severe mental strain, the action of the rays will relieve the congestion in your body and greatly refresh you. The most valuable work that the ultra-violet ray does is in connection with tuberculosis. A victim who is suffering from chills, fever, and severe body pains will find that these disap- pear after afew treatments. His appe- tite will improve, and he will grow stronger and heavier. As the treat- ments are repeated, his skin will be- come tanned, changing in time to a copper color, and then to a deep brown. Do not be alarmed; the darker he be- comes the better he will feel. Anemic people, who are in danger of getting tuberculosis should have ultra-violet ray treatments regularly; they will improve the composition of the blood and help ward off the dread disease. Poor circulation and low oxidation are also helped by ultra- Picking Cotton by Machine It works five times faster than the hand LTHOUGH we have grown used to machines on the farm, there is one agricultural operation that has for years baffled the inventors’ skill—that is, the picking of cotton. Even in this day of machinery, cotton the world over is generally harvested by hand. But an American engineer has re- cently perfected a cotton-picking ma- chine that reminds one of the machine clippers used for removing the wool from sheep. The picker head, contain- ing three drums rotated by a flexible shaft from the tractor on which the apparatus is mounted, is attached directly to a large flexible tube through which the picked boll of cotton is drawn by suction from a small blower also carried on the tractor. A part of the equipment is a container for the harvested cotton, in the form of a large box or an ordinary sack. The big flexible tube leads to this container. The operator simply holds the picking head against the cotton-boll and the machine does the rest. First the boll is caught by the brush- carrying drums in the head, and their rotation pulls the fluffy sub- stance through to a third rotating member having prongs on it, which comb the cotton free of any part of Here is the picker head, with three drums rotated by a shaft from the trac- tor on which the apparatus is mounted 16 Popular Science Monthly Rheumatism is promptly relieved by ultra-violet ray treatment. The rays pass through a quartz lamp and are di- rected at the diseased part of the body violet rays. Neuritis, lumbago, colds, influenza, pneumonia, asthma, nasal and pharyngeal infection, ulcers, boils, and various skin diseases improve after treatment. Persons who have a tendency to baldness should seek the ultra-violet ray specialist. In all branches of medical science the ultra-violet ray lamps are coming into use. They check the increase of injurious bacilli, thereby helping to cure many contagious diseases, and frequently they eliminate the necessity of an operation. The operator holds the cotton-picking machine against the cotton-boll, and the picked boll is sucked through a tube into a sack the stalk or leaves that may remain with the cotton after it has come this far into the head. The sectional view shows clearly how the device works. Drive for the rotating drums in the nead is by means of a flexibly jointed shaft driven by a small garden tractor. The maker of this implement claims that one person operating one of these pickers can harvest five times as much cotton in a day as he could if he did it by hand.

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The Pons-Winnecke Comet Will Almost Hit the Earth © Modern Publishing Company ACCORDING to early calculations, the present orbit of the Pons-Winnecke comet was expected to col- lide with the earth in June. On April 10 Professor Barnard, of the Yerkes Observatory, located it, and later calculations indicated that the expected collision would not occur. Even should the earth pass through the head of the comet itself, there are reasons for concluding that nothing would happen beyond a great shower of meteors. It is affirmed that comets’ heads are not solid, but represent a huge flock of small meteoric bodies and 17 Drawing by >ciiven Bolton earthly substances, often displaying an illumination of electric origin. In the past the earth has encountered more than one tail, and probably that of Halley’s comet in 1910, without damage. A comet’s tail is so rarefied that it totally vanishes when close to or touching the earth. Our atmosphere acts as a safeguard against the intrusion of meteoric matter by dissipating most of it into vapor before it has time to reach the surface of the earth. Other- wise an encounter with a comet’s head might make matters decidedly uncomfortable

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HEN disease has taken firm hold on the breathing apparatus, it becomes necessary to aid nature by carrying germ-destroying agents di- rectly to the seat of the trouble. In normal respiration, air invariably laden with germs and impurities is drawn into the lungs by the expan- sion of the chest, which causes diminution of the air pressure in the lungs. All the air thus inhaled does not, as a rule, penetrate to the deep-seated regions. Dr. Arnold Gschwend, a practitioner in Paris, has con- ceived of a plan for introduc- ing pure air charged with vapors of disinfectant medica- ments into the lungs under pressure. One of the pictures accompanying this article il- lustrates the boiler plant in which the steam for the atom- izers is generated. Another Inhaling Medicine The latest method of treating tuberculosis disinfecting vapors are administered through a tube that the patient holds in his mouth during the treatment. Dr. Gschwend’s sanatorium has almost none of the appearance of the ordinary doctor’s plant. Separate compartments accommodate the pa- picture shows patients taking inhalation treatments. The HERE has been developed and patented by Guyon F. Greenwood, of Quebec, a metallurgical apparatus for the production of iron that avoids many of the disadvantages of the blast-furnace. The essential features are the reduction of iron oxide by means of carbon with the exclusion of air in an electric resistance furnace sand at a temperature and pressure favoring the production of carbon monoxide, the latter being used as fuel in a gas engine and generating electric energy utilized in . heating the electric furnace. The process is carried out as illus- trated. The electric resistance fur- nace produces coke from coal, and this is fed into another furnace from a hopper and preheated by the hot exhaust gases from a gas engine. The fuel for the engine is obtained from combustible gases from the coking of the coal. The gases pass through a scrubber before they reach the engine. Ore and flux, to- gether with the coke, are fed into the electric furnace, the ore and flux being preheated in the hopper by the heat in the exhaust gases from the gas engine. The electric furnace is maintained at a tempera- ture of about 750° C. and at a slight vacuum without the admission of oxygen. The iron oxides are re- duced without producing a slag; the result is carbon monoxide, which is The boiler plant in Dr. Gschwend’s inhalatorium in Paris; here is generated steam for treating patients Pig fron Made without a Blast-Furnace used as fuel for the gas engine, which in turn drives an electric generator that supplies the furnace with current. The raw iron is fed into the lower electric furnace, where the impurities are slagged off. A minimum amount of heat is wasted and sufficient power is developed by the gas engines to fur- nish the electric energy for the electric furnaces. The production of iron with this process is carried to the point of refining. Popular Science Monthly ei A patient taking the latest treatment for tuberculosis; back of the screen is the ap- paratus for charging the steam with medicine tients, and in each one is a stool, also an inhaler jutting out from ascreen. Back of the screen is located the apparatus for charging the steam with medicines, and provision igs made for measuring and regu- lating the temperature of the vapor, the percentage of dis- infectant, and the pressure deemed necessary in each case. Kill Molds on Lumber by Steaming OLDS thrive on warm, moist wood. In a dry-kiln molds often obstruct the circulation of air through the pile. The Forest Products Laboratory found that the _ surest method of stopping this growth is to steam the stock at 170 or 180 degrees for about an hour. This kills the mold, and at the same time the satu- rated air prevents such rapid surface drying as would eventually injure the wood. COAL HOPPER ORE AND FLUM 2 ‘HOPPER PEAT aia COMBUSTIBLE GAS oe (HN) Hi a Sonat | : | : BAN Al | BS | ee ri i ee rf ‘ bie! é eee | $ ; +. : = sf u OG GAS SCRUBBER ELECTRIC COKE “FURNACT MONOXIDE FUEL me F — ) 44 4 { " w= GASTO/ | | ' ENGINE TO ENGINE > ELECTRIC {RON SMELTING FURNACE Se 6 © 601.0 © 6.6 4 et eGo. These electric furnaces are used in the reduction of iron ore. The inventor of this system claims that this method will be able to compete with blast-furnaces in localities where electric energy is cheap 18 re = a ij

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July, 1921 No longer are coins counted and packed by hand. This machine does the work. There are auto- matic stops that lock the feeding mechanism when a_ predeter- mined amount has been reached Several girls were formerly em- ployed to operate the transfer- counting machines shown at the right. Now, however, the trans- fers are weighed in a lot, instead of being counted one by one: it is more economical Dimes, nickels, pennies, and metal tickets are shaken through this machine. The tickets drop through the first screen into a tray. The next screen removes the dimes, the third the pennies, and the fourth the nickels Counting Transfers and Cash Fares 420 Hammer-Blows a Minute MECHANICAL hammer has been invented that can deliver as many as four hundred and twenty blows a minute when speeded up. The strength of the blows may be varied by adjusting a spring.- As this spring is pulled upward, the blows become lighter; when the screw is turned down, the blows become heavy. Differently shaped noses for the hammer, and anvils to correspond with them, may be used for special purposes. In the illustration on the left the operator is shown hammering out a concave piece of metal from a fiat sheet. To do this he uses a convex anvil and a concave hammer. With skilful manipulation pieces of sheet metal may be formed into prac- tically any shape when the proper hammers and anvils are used on the machine. The compressed air required to drive the hammer is delivered under a comparatively low pressure. The machine may be driven for a few cents a day. 19 Transfers and coins are sepa- rated by means of a vacuum de- vice that sucks up the trans- fers. Formerly the slow grav- ity system, shown above, was used. The contents of the fare box were dumped into a screen that was agitated by hand; the coins fell through, ‘ieaving the transfers Is the Population of the Earth Increasing ? OMEBODY has reckoned that if the earth’s population had in- creased 41% per cent every hundred years since the birth of Christ, by now there would not be standing-room left on the globe, including all the islands. Yet England and Wales in ten years increased their population 161 per cent, and the increase in the United States has been much greater. The earth’s population at the pres- ent time is about sixteen hundred million. Different parts of the earth vary greatly in the matter of density of population. Certain portions of China, the Ganges valley, and parts of _ Europe are too crowded for comfort. On the other hand, large tracts of Central Asia, Russia, the Americas, Africa, and Australia could accommo- date many more people. The Turks by their religious fanati- cism have caused devastation in the last five hundred years in the valley of the Danube, in Macedonia, Asia Minor, Syria, and Mesopotamia. These countries, as a result of massacre and famine, are dried-up deserts.

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Popular Science Monthly How the Pyramids Would Be Built Today Applying modern engineering methods INETY million cubic feet of stone sprawled out over thir- teen square acres and reaching nearly five hundred feet into the sky, makes up the tomb of the tyrant, Cheops. A hundred thousand naked slaves toiled for twenty years in the blistering Egyptian sun to build this pyramid. Hordes of dark-skinned men pulled, tugged, and hauled under the sting of the lash. Great stones moved slowly, inch by inch, foot by foot, into their place high up on the pyramid. For centuries the sand-laden winds have pitted its face. But the miracle in stone stil] stands as an enduring mohument to the bold engineering spirit that willed it into being. It is indeed a stubborn triumph over na- ture—the fulfilment of a passion for gigantic undertaking. For four thou- sand years the mighty shadow of this imposing mass of stone has crept across the still valley of the Nile, the red sun blazing behind it. We can picture great masses of brown men tugging at the stubborn stones, the whip snapping at their heels and the hot desert breezes fanning their sweated brows. Wecan see in our mind’s eye the inert stones responding reluctantly to their taut muscles. It was not a scene of wild disorder, of shrieking whistles, throb- bing engines, and shouting men. It was merely the inhuman application of man-power to overcome the dead resistance of tons and tons of stone. How Did They Do It? How did ‘this ancient people pile up this colossus? No one really knows. Herodotus and Diodorus, who obtained their information from ancient Egyp- tian priests, have given us a credible description. Many modern theories are modifications of the engineering data disclosed by these writers. Limestone was the principle ma- terial used. This was quarried about twelve miles from the site of Cheops’ pyramid. It was cut in large blocks by an ingenious application of one of the most elementary laws of physics— that of cubical expansion. A deep groove was first cut into the stone by the use of tools that are today ridic- ulously crude. Wedges of soft wood were then forced into these grooves. Boiling water poured on the wedges caused them to expand and this expansion broke off a huge block of limestone. This wearisome process was repeated thousands of times by slaves. The huge stones, obtained with so much trouble, were then loaded By Raymond Francis Yates Drawings by Charles L. Morgan on sledges and hauled away to the building-site. Historians have long believed that these ancient builders used a long earthen ramp or incline up which the stones were dragged by thousands of slaves. This ramp was added to as the work progressed, gradually in- creasing in height and length. When the last stone capped the pyramid, the ramp must have been about five hundred feet in height and several miles in length. To build such a ramp has caused engineers to wonder A laboring mass swarming like ants at the base of a half-finished hill. A theory has been advanced that the Egyptians finished 20 if the Egyptians may not have used a simpler method. A modern engineer, who recently investigated this subject, has rejected the ramp theory as being utterly impractical. He asks, ‘‘Why should the Egyptians have thrown up a huge earth mountain to build another smaller mountain of stone?’ He sug- gests that the incline of the pyramid itself was used in hoisting the stones in place. Details of Construction This method will be better under- stood if a brief account is given of the general construction of the pyramids. the outside of the pyramids as the work pro- gressed. Huge stones were drawn up the sides by ropes pulled by thousands of men

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July, 1921 The stones were placed in layers, step fashion. The steps were filled in with a triangular-shaped piece of granite, leaving a perfectly smooth incline. Were the blocks of stone hauled up this incline with long ropes pulled by slaves? This is the modern engineer’s hy pothesis. But how should we build the pyra- mids today? In lower Broadway, New York, an ironworker foreman steps to the edge of the structure, waves his hand to an engine operator twenty stories below, and a five-ton girder mounts skyward. Imprisoned steam or a current surging through an electric motor would have literally tossed the limestone blocks of the pyramids into the air. We Should Use Concrete With modern devices we could build a pyramid in a year. There is no doubt that concrete would be used jn its construction. This would take the place of Egyptian limestone. An enormous concrete-mixing plant would be erected. This would be capable of handling thousands of tons of concrete aday. A great steel tower, or several of them, would then be built. Fresh concrete would be rushed to these by a multitude of bucket conveyors from the concrete-mixing plant. The con- crete would be whisked to the top of the towers and from this point it would flow down like water to the walls. would run down for months, and up, up, up the great pile would go. The interior of the pyramid might be filled with broken stone or sand. The steps outside the wall could be filled with triangular pieces of granite without engineering difficulty of any kind. Given a year’s time, only one thou- sand men would be necessary to build a pyramid today. They would prob- ably receive a wage averaging $4.00 a day. This would total $1,200,000. The cost of labor in the building of the pyramid of Cheops totaled only $200,000. This is what it cost to feed the one hundred thousand slaves for a period of twenty years. Times have changed. Today there would be no continuous period of unremitting labor = Seer om, Le Sea 4 - BA ’ SS ‘ ee Ao (yD —_ wane Zo This illustrates one of the older theories of the construc- Some engineers believe that they built long earthen ramps and pulled the granite and tion used by the Egyptians. Unending streams of concrete _ Today, provided with modern equip- ment, a thousand men could build in one year the pyramid that took a hundred as in the past. When the pyramids were built, the slaves followed out an unmerciful grind from early morning until the sun had set. Today ma- chinery would do all the hard work. All the forces we control would figure in the construction of the pyra- thousand men twenty years to build; construction would be largely amatter of mixing, conveying, and pouring concrete mids today. Electricity, chemistry, and steam would take the lead. Every unit of our engineering knowledge would take its part. We have gained invaluable experience in the carrying out of great projects, many of which are aS marvelous as the pyramids. 21 limestone blocks up the incline. been several miles long. Traces of ramps are left about the smaller pyramids, but none near the larger ones Such a ramp would have

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© Modern Publishing Company Drawing by G. H. Davis Launching a Life-Boat by Tractor It was at the Hunstanton station of the Royal National Lifeboat Institution in England that the idea of using the caterpillar tractor to launch life-boats was evolved with such success that now twenty English life-boats are being provided with this means of launching. ’ The tractor is driven by a 35-horsepower gasoline engine, and the life-boat on its carriage is connected with the tractor by a rigid steel pole. A water-tight casing protects the vital parts of the engine when it is submerged in four feet of water. . When the tractor, drawing the life-boat, reaches the water’s edge, it is uncoupled. It then passes around to the stern of the boat, and by a special arrangement of ropes and pulleys launches the iife-boat. Four men and one tractor can do the work ordinarily accom- plished by ten horses and ten men

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July, 1921 Launching Life-Boats by Caterpillar Tractors Modern methods save time where it counts most TANDING on the seashore on a fine day, it is difficult to believe that a great storm is approaching from beyond the horizon: that in a few hours great waves will be racing in with a howling tempest of wind, break- ing with almost irresistible force, flinging tons of water on high, and sweeping the shore in swirling masses of foam. But all this is known at the life-boat station, where the storm signal is hoisted. As it grows dark the wind increases to a gale, and watchers on shore are at last startled by the burst- ing of a colored rocket out at sea, fired by a ship in distress. That sum- mons must be obeyed—and obeyed quickly, for there are human lives at stake. Rapidly members of the crew make for the boat-house. The call goes forth for horses—ten powerful crea- tures. Then occurs the almost in- variable delay of collecting them from local stables—delay that may result in the bravest efforts being made too late. At last the horses are harnessed to the under carriage on which the life- boat is mounted, and proceed to draw their seven-ton load down to the water’s edge. Now comes the task of hauling it into the seething breakers By P. J. Risdon. English correspondent for the Popular Science Monthly —a procedure often resulting in drown- ing or such injury as to necessitate the destruction of valuable animals—small wonder, when one thinks of the poor brutes battling with the waves, slip- ping on seaweed-covered rocks and boulders, and floundering in deep holes. It seems strange that only recently has the idea of applying motor traction to the launching of life-boats been developed with practical results. The honor for the development is due to the engineers of the Royal National Lifeboat Institution of England— whose efforts have resulted in success- ful trials of the caterpillar tractor illustrated on the opposite page. This tractor is driver. by a 35-horsepower gasoline engine. Hunstanton, Nor- folk, where several varieties of beach exist, was selected for the trials. The first tests were something like those to which the ‘“‘tanks’’ used in the late war were subjected, and included the negotiation of sand-dunes and the mounting of vertical faces of rock. The life-boat and carriage were se- cured to the tractor, which made light | . work:of-its task, drawing its load across the sand at a speed of six miles an hour. As will be seen, the connecting attachment is a rigid braced steel pole or strut, hinged at one end to the tractor and at the other end to the boat-carriage. When the first effort at tractor launching was made, the carburetor and magneto of the engine were not properly protected, with the result that the engine stopped and the mechanic and another man _ were marooned on the submerged tractor, and had themselves to be rescued! Subsequently a water-tight casing was provided effectually to protect the vital parts of the engine when sub- merged in four feet of water. The modus operandi is as follows: The tractor draws the boat and car- riage down to the water’s edge. It is then uncoupled, when it passes round to the stern of the life-boat and pushes the carriage out into the water. By means of a special arrangement of ropes and pulleys the tractor then hauls the life-boat off the carriage and launches it. Twenty life-boats in England are being provided with this practical device, which ought soon to supersede the antiquated method of horse launch- ing, since four men and. one tractor can do the work of ten horses and ten men far more rapidly, safely, and efficiently. How a Repelling Arc Regulates Itself HE inventor of a new electric furnace has em- ployed a principle that makes his device unique. A repelling are is used. The layman can understand the principle by considering the electric arc light used to illuminate city streets. Here an electric current is caused to flow across an air-gap formed by two carbon electrodes. The carbons are first brought together and then separated. When they are brought together a spark is produced, and the heat of this spark causes carbon vapor to fill the gap when the carbons are brought out of contact. Carbon vapor is a good con- ductor of the electric current, and the current continues to flow across the gap, generat- ing terrific beat and a great amount of light. This furnace operates on practically the same principle. The electrodes TILTING COUNTERS WEIGHT ELECTRODESS MELTING FURNACE | AND LOWERING ; ELECTRODES — } t é we The electric turnace with repelling elec- trodes. When no current is flowing, the electrodes come together. When the cur- rent is turned on, the electrodes repel each other and an arc is ‘“‘drawn’”’ be- tween them 23 CABLES FOR RAISING ADJUSTABLE WEIGHT ae or the carbons, however, are not mounted in the same manner. They are balanced on knife-edges, with counter- j weights attached to the upper ’ ends. When no current is flowing through the furnace, the elec- trodes come together. When the current is turned on, the electrodes repel each other and they fly apart, an electric are appearing between them. The repelling of the electrodes is caused by the ‘‘flow forces’’ of the electric current. The are is_ self-regulat- ing, since an increase in the amount of current flowing across the arc will cause an increase in the flow forces, which in turn move the electrodes farther apart. By adjusting the weights on the ends of the electrodes the arc may be regulated within wide limits. This furnace has been found especially useful in the non-ferrous iron industry.

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Popular Science Monthly Be af Re The smoke is led through a shaft and through a shower of water, which precipitates the soot and cinders; they are then conducted to the sea UPTAKE Giving the Smoke a Shower-Bath N order to do away with smoke from ships’ funnels, an Italian invented an apparatus consisting of a slightly conical doubled-walled shaft, placed in the lower part of the funnel. The space between the walls is divided into two compartments. Warm water from the condenser is conducted into the lower compartment, while the upper one is supplied with cold water furnished from a force-pump. The smoke enters the shaft at its lower end and passes through a shower of water, warm in the Jower part and becoming cold in the upper part. This causes Smallest Pass HE tiny Eskdale railroad, running between Ravenglass and Boot, in England, is not a toy railroad, though it looks like one. It was origi- nally constructed for mineral traffic, but is now much used by sightseers in the lake district, and from Boot many delight- ful excursions may be made. The gage is only fifteen inches, and the rails, designed for’ heavy traffic, weigh forty pounds a yard. The little loco- motives are a triumph of engi- neering skill.. The boiler is six feet six inches long, the working steam pressure 130 pounds. There are two types of cars. One, for summer use, is roofless and the other is enclosed. a gradual cooling of the gases, while the shower of water pre- cipitates the soot and fine par- ticles of cinders carried with the gases. The water enters the shaft through small openings in the side, and also forms a ring or curtain at the lower end through which the smoke from the furnace passes before it can reach the funnel. The water is collected into a conical basin and is conducted to the sea. enger-ITrain Another Tractor to Lighten Freight-Yard Work ee. sheet of steel no larger than a large sheet of cardboard, and not much thicker, can be moved about by one man without much trouble. But how about fifty of these stacked together? The old way to unload a freight-car containing these sheets of steel was to use a truck hauled by a number of men. Now the small tractor does the work in a simpler and easier manner. It does away with all the hard tugging and the straining of muscles. With greater speed it pulls the trucklcad of sheet steel across the freight-house floor, and hurries back for the next load. Thirty years ago there were only 809,981 sheets and plates of steel pro- duced annually in this country, while to-day there are more than seven million. Think of the tremendous amount of energy required to accomplish the moving of so many sheets and plates of steel! No wonder that an easier way had to be found. With the greatest ease the little trac- tor pulls a truckload of steel sheets When and How a Ship Is Arrested ID you know that if a ship’s debts are not paid the ship can be ar- rested? Even though it is not actu- ally the ship’s fault, a writ is nailed to her mast, a watchman is sent on board, and the ship is not allowed to move until her debts are paid. The creditor must, however, be sure of his case; if not, the ship’s owner may sue him for delay and loss of use. There- fore the usual procedure is to send the owner several warn- ings, as by watching the ship- ping-lists the creditor can fol- low aship’s movements. If the owner makes no response, the warrant for arrest is issued, and the ship must submit to her fate. There are on record cases in which crews have been com- pelled to order the arrest of their own ship at the end of a Built originally to carry minerals, this tiny railroad voyage in order to collect their is strongly made; it is now patronized by sightseers wages. 24 ric an. or Tt ARG hi ee ME = 88 Ju

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July, 1921 Music in the Zoo HE old saying that music has charms to soothe the savage breast may be true in some cases, but a recent demonstration at the Central Park menagerie in New York city failed to prove its truth in the case of caged’ animals. When some musicians, playing wind and string instruments, appeared be- fore the cages, the animals sat up and took notice—at first. Then most of them became restless. The large crowd of onlookers may have had something to do with their excitement, as well as the noisy jazz, which seemed to arouse the animals. According to Dr. E. L. Scott, of the Department of Physiology of Colum- bia University, one of the scientists present at the experimental demon- stration, the results‘as a whole did not indicate that the musical noise had any very pronounced effect, although the behavior of some of the animals was un- usual. The polar bear ex- hibited astonishment when the trombone and clarinet began a duet. The bear at first sat up in the attitude of a dog when it begins to howl. Its jaws opened, and there was a nervous, trembling movement of the cheek muscles, and he looked as if he would like to howl if he could. Instead, he stood up and began to sway excitedly from side to side in a curious kind of dance. A small tame wolf in an adjoining cage at first ran into its den under cover, then came out and ran wildly around, panic-stricken. The elephant was the most inaif- ferent of all the animals. perhaps sagacious enough to know at once that the whole thing was a joke. That a dog is keenly sensitive to music is well known, but what are the emotions aroused?’ Does it howl for joy or for pain? Are some primitive emotions wakened that touch its racial memory and bring back the mystical terror of the wilderness, the same emotions that make a wolf howl in the wistful loneliness of the moon- light? These are questions that future ex- periments may help to solve. i Playing music had little visible effect on this elephant, who accepted sweet strains and jazz with stolid indifference Lifting and Weighing at One Operation HOWN at the right is a “‘load-and-look”’ idea. Bulk merchandise is usually sold by weight, and speeding up the weighing has always been a problem. With the crane scale here shown a manufacturer may load his freight-cars or -trucks and weigh the merchandise at the same time. , This scale is hooked on to the crane. A hook on the scale then accommodates the chain that binds the goods together. In this way the lifting and the weighing are done at the same time. While the load is being tt ? placed on the freight-car a clerk jots down the weights. Each scale is equipped with a tare beam that automatically deducts the weight of chains, hooks, boxes, and the large lifting electromagnets. $ — A es ns ——— ——— 3 . ee He was Here is a small hand-propelled sowing- machine that can be used to plant one, two, or three rows with littie effort A Machine for Planting Small Gardens HEN seeds are to be planted in beds or rows, it saves time to use a sowing-machine. The illustration shows a type that may be used for planting in one row or in several paral- lel rows. It consists of a container divided into compartments. Each compartment has an opening at the bottom, the size of which can be regulated according to the size and quantity of the seeds. The container rests on spiked wheels and is pushed by means of a handle. Part of a Rib for a Nose ECENTLY an_ operation was performed on a man whose nose had been so injured that he was unable to breathe properly. First the broken section of bridge bone that caused the ob- struction in the nose was re- moved. The next step was to cut a bit of bone from one of the man’s left ribs, and to in- sert it.in place of the bridge that had been removed. When the physicians had completed the operation, the patient’s appearance was so changed, and so much for the better, as to make bim almost unrecognizable. He could By attaching this big scale to the crane that lifts the load to the freight-car, the goods can be weighed while being loaded 25 breathe perfectly, and his health was therefore improved. Alto- gether the operation was a great success.

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Popular Science Monthly Discovered: a New Phenomenon of Electrical Attraction It will lead to interesting industrial developments attraction has been discovered by two young Danish engineers, A. Johnsen and K. Rahbek. It is a discovery that will eventually lead to new commercial and industrial devel- opments, since it has been found pos- sible to apply the phenomenon. At present we are familiar with two forces of attraction that are electrical in nature. We have magnetic attrac- tion and electrostatic attraction. Let us imagine (the illustra- tion in the center of the page will help us) that we have a slightly curved sheet of metal. This metal will be covered on one side with a semi-conducting sub- stance, such as gelatine. Close to the surface of the gelatine an- other flexible piece of sheet metal is arranged. The terminals of a 440-volt generator are connected with the metal plates. The one that is not in actual contact with the gelatine (in this case the aluminum foil) will be drawn toward the gelatine with con- siderable force. The passage of an infinitesimal fraction of an ampere from plate to plate through the gelatine will cause this attraction. The action ceases when the current is turned off. This attraction is the new force discovered by the Danish engineers. A NEW electrical phenomenon of

GELATINE Mi- ‘ CONDUC How the New Force Is Applied , ’ BRASS PLATE A number of semi-conducting conpuctor substances may be used in place of the gelatine. Agate and slate have been used successfully. The diagram shows an agate disk that forms part of a special electric relay. This may perform any mechanical function when the current in an electrical circuit (of which it forms a part) is either

ELECTRIC GENERATOR By Alfred Gradenwitz turned on or off. When the current is on, the metal disk will be attracted to the agate disk, and it will turn with it. When the current is turned off, the attraction will cease and the agate disk will separate itself from the metal disk. The arrangement is really a clutch con- trolled by this new form of attraction. A telephone receiver has been de-

Messrs. A. Johnsen and K. Rahbek, the young Danish scientists who dis- covered the new force of electrical attraction described in this article

WEIGHT ~OPERATED CIRCUIT CLOSER

The arrangement used for the demonstration of the new at- traction is shown at the left. The diagram at the right illus- trates an electrical relay or clutch based on the new principle WIRE TO BRASS DISK (MOTOR DRIVEN) THIN METAL METAL cone) jew veloped by the use of this new prin- ciple. A constantly rotating metal core is covered with gelatine. A thin metal band is pulled tightly over this. One end of the sheet-metal band is connected with springs that keep it taut, and the opposite end is connected by a thin wire with a diaphragm mount- ed in a receiver. The fluctuating cur- rent from a telephone transmitter is allowed to pass through the gelatine on the cylinder. The attraction be- tween the gelatine and the metal band varies with the current. The springs are constantly pulling the metal in one direction, while the attraction between the band and the revolving drum (that va- ries with the voice currents) is trying to pull it in the opposite direction. This causes the metal band to vibrate in sympathy with the voice currents, and the voice will be reproduced at the dia- phragm. Only a Small Current Needed The intensity of this new force of attraction is tremendous, con- sidering the small amount of cur- rent necessary. The passage of 1,000,000 amperes from plate to plate -through the gelatine will cause an attraction sufficient in intensity to overcome a weight of nearly two and one quarter pounds. The new phenomenon may be better understood by reference to the attraction that exists between the plates of an electrostatic condenser. These are drawn toward each other with a force that increases in- versely as the square of the dis- tance. Reducing the distance one third increases the force nine times. The same law appears to hold true for this newly dis- covered attraction.

TELEPHONE RECEIVER

{ WIRE: TO METAL BAND HALF-CONDUCTOR CYLINDER (MOTOR-DRIVEN) Sl

WIRE CONNECTION Sa re,

METAL CORE TENSION SPRINGS “motor Here is the new telephone receiver that operates on the newly discovered principle of electrical attraction. or agate-covered revolving cylinder. A metal band is pulled taut over a gelatine- The attraction between the cylinder and the band is caused to fluctuate by the varying intensity of the voice currents 26 7 ie i

July SI eee ae ae” ee ee ee ee Or re

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July, 1921 Shipments that Write Their Adventures How the barograph can be used in business By John Edwin Hogg HEN a barograph is spoken of, most of us think only of a deli- cate little instrument that is used for recording altitude. A baro- graph is nothing but a _ recording barometer. Recent experiments have revealed that it is possible to use the barograph as an aid to commerce in the production of records of every form of travel by land and air, com- puting the average time consumed in any given journey, and tracing the movements of delicate and costly ship- ments. The range of the commercial appli- cations of the barograph has been widened by a series of experiments conducted by Dr. Ford A. Carpenter, of the Department of Meteorology and Aeronautics of the Los Angeles Cham- ber of Commerce. Numerous baro- graph records have been made covering trips by airplane, automobile, horse- back, afoot, by train, interurban elec- tric, free balloon, dirigible, and almost every other practicable medium by which human beings and merchandise travel on land and in the air. Barograph records have been worked out to such a degree of accuracy that a glance at them suffices to tell just what method of travel was used. Similar records, if applied to shipments of costly merchandise, or to merchandise where the element of time consumed in transit is of great importance, will show us just how the shipments were handled. Twenty express packages might be sent out, each consigned to a different destination, and to be forwarded by different modes of travel. If a baro- graph were placed in each package, and the records compared after reaching the destinations, we could tell instantly which parcel traveled by airplane, which one by train, by motor-stage, or other conveyance. Time and Siliiitiad Recorded The elements with which the barograph deals are merely those of time and elevation. The spaces between the vertical lines of the record represent time, and the spaces between the horizontal lines represent elevation. The clock mechanism may be calibrated to operate for twenty-four hours or more. Let us suppose that we wish to record the movement of so valu- able an express shipment as a motion-picture film. A barograph is set in motion, and wrapped with the package in New York. The 44 _— —— —+~—4 4B Bake A barograph record. Spaces between the vertical lines are for the time record, and those between the hori- zontal lines for elevation. A clock mechanism controls the length of time for its operation, which may be twenty-four hours or longer mechanical record of its travels begins at once. If the package lies in the express office for half an hour before it is taken to the train, the fact will be registered. The barograph places a dot on the chart every two minutes. During the period that the shipment remains stationary fifteen dots will be placed in a horizontal line across the paper, because during the interval of half an hour the instrument will regis- ter a dot every other minute at a stationary elevation, which will be shown as sixty feet—assuming that sixty feet is the elevation above the 4 : a he A barograph is enclosed with each package sent on an express journey, and the instrument keeps a record of its travels, which is read when the package is opened 27 vrs ¢ 9 012) 234 3 ee kia ‘ hve, 4 RS Rid 69 191] hs Courtesy San Liiego Union The word “‘barograph” immediately reminds one of aviators; but a barograph is nothing but a recording barometer, and Dr. Ford A. Car- penter, of Los Angeles, conceived the idea of applying it to industry ‘sea of the New York express office. If the package is then put in a wagon to go to the railroad station, the in- strument will immediately begin regis- tering time with relation to the vary- ing elevations that the wagon is driven over. The speed with which the dots ap- pear with relation to the changes of elevation indicate whether the pack- age traveled in a slow-moving wagon or a motor-truck. If the package then lies in the railroad station for half an hour, the barograph will record another thirty-minute period at a stationary elevation. It Even Keeps Tab on the Trains! Just as soon as the parcel is under way in the express car, the barograph begins registering time in relation to railroad elevations. At the end of the journey we have simply to compare the barograph record with the railroad time-table to discover whether the train was on time when it reached its destina- tion. Similarly, if the train was an hour late at Buffalo, but arrived at Detroit on time, that fact will be clearly shown on the chart. Since it is safe to assume that no two cities in which the train stopped will have identically the same eleva- ‘ tion, and that the barograph has recorded the length of time of the stops, and the contours of the earth between stops, there is no possibil- ity of mistaking the identity of the cities represented by the stops when reading the chart. If the record is taken between points where the earth’s contour is rugged, the chart will show numerous prominent and sudden changes of elevation.

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Popular Science Monthly Staging the Jutland Naval Battle for the. “Movies” Drawn by W. B. Robinson, by courtesy of the Ideal Film Renting Company and the British Instructional Films, Ltd. s Paae The Jutland’ Film" in the making. July, After the ei s have been moved orward Yie™ofan inch, smoke is added “aind the operator makes a half-furn of the tiandle of the camera. = it ome TH! naval battle of Jutland was one of the few great events of the war in which the “movie” man did not figure. A moving-picture producer of England decided to re-stage the battle with the use of tiny models. It was a tremendous task, since every detail of the move- ments of the German and English fleets had to be carried out. Mathematicians were called in, and every movement made by the models had to be carefully calcylated. Each boat was moved only a sixteenth of an inch at atime. A certain maneuver of the English fleet required eighty thousand movements of the vessels by. hand. Only sixty feet of film was required to record this movement, which took several days to carry out. Tiny chemical pellets were used to get the effect of a burning vessel. These were set off with a match. The gunfire was produced by blowing smoke through small tubes. The board upon which the battle was staged measured eight feet square. Each of the tiny models em- ployed was scaled down to the proper size. The camera used in taking the pictures was placed above the “battle” to get the effect of an aerial view

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July, 1921 Teaching Tricks to a Dog It’s easy, but it requires infinite patience By Latimer J. OY RUSH, of the Ringling R Brothers and Barnum & Bailey Circus, can train a dog or a monkey in six weeks. In the “big- gest show on earth’’ the audience sees a fluffy little dog balancing himself up- right on a slack-rope. The dog puts his fore feet upon the rope,’ then mounts it with his hind feet, and for an instant balances himself on all fours. At a word from his master he stands upright, cleverly keeping his balance on the swaying rope. How did he learn this trick? ° First he was taught to stand upright on the floor— an easy trick taught to many dogs. Then he was made to stand upright on a large rope stretched upon the floor. Rush holds a thin light cane and speaks to the ani- mal in a firm tone, but with- out a trace of anger. A dis- play of anger spoils the work of days; for dogs and mon- keys are very high-strung, temperamental creatures, quickly responsive to the moods of people. When the dog had learned to stand up on the rope on the floor, the rope was elevated a short distance. Great patience was now required to keep him balanced. He soon found it more difficult to stand upright on the slack- rope than on a rope laid on the ground. After half an hour of failures the dog for a moment succeeded. Then Rush patted him. Occasion- ally after a successful exhibi- tion Rush gave the dog a small piece of meat, a lump of sugar, or something as a reward. In the case of Jocko, a big baboon, the reward was literally a ‘“‘chew of tobacco.” “How did you teach Joe [a monkey] to ride a bicy- cle?” I asked Rush. “Well, Joe was first taught to sit upright in a small chair. Then he was taught to sit upright in a little tri- cycle, his feet tied to the pedals. As the tricycle was pushed around the room, Joe learned the art of pedal- ing. Next he was placed on a small bicycle, a guide-rope attached to the collar around his neck. This guide-rope, which I held, kept Joe - moving in a circle. After Wilson a few mishaps the monkey found that he could stay aboard by balancing himself, and that it was easier to keep his balance going around in a circle than in going straight. Finally the rope was removed and Joe rode around by himself. Three stakes painted white were planted in a row, and Joe was piloted by the guide-rope Monkeys and dogs are high-strung and tem- peramental. Their trainers must never show any trace of anger A dog, unlike a cat, does not naturally climb a ladder: the dog here shown was taught the feat by degrees Each dog was taught his part of this ensemble trick; then the four were brought together for their act 29 so that he would circle around one after another. “Joe! Joe! Joe!’ com- manded Rush, pulling gently on the rope on the side he wished the monkey to travel. When the guide-rope was removed, he still gave the same commands, simply the word ‘“‘Joe!’”’ firmly uttered. He always stood in front and on the side that. indicated the direction to be followed. Finally Rush could stand in one spot and give the com- mands and the monkey would obey. He remembered what was wanted of him. Dogs and monkeys can be taught tricks when they are about a yearold. The train- er wanted to teach Joe how to juggle plates. First, Rush sat him on top of a tall stand and leashed the collar-rope so that Joe could not get very far away. Then four wooden blocks about an inch thick and five inches long by three inches wide were tossed at Joe one after another. At first the monkey warded them off to prevent them from striking his face. Rush continually commanded, *‘Joe—Joe,”’ each time throwing a block. At last Joe caught one of them, and Rush patted him affection- ately on the head. Within half an hour, after Rush had made about forty trips pick- ing up the blocks, Joe caught all four of them. The first attempt to teach him to jug- gle was declared finished. Joe was pat- ted and kind things were said to him. Then he was given a raw sweet

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ain Popular Science Monthly Staging the Jutland Naval Battle for the “Movies” Drawn by W. B. Robinson, by courtesy of the Ideal Film Renting Company and the British Instructional Films, Ltd. oF 5 The JUuHand’ Film nid the Ebiee awe boon totale er Ihe Ships have been moved forward ieokan inch, smoke is added the operator makes a half-furn of the fandle of the camera. = it oo Moving each ship forward Vet ofan inch. "THE naval battle of Jutland was one of the few great events of the war in which the “movie”? man did not figure. A moving-picture producer of England decided to re-stage the battle with the use of tiny models. It was a tremendous task, since every detail of the move- ments of the German and English fleets had to be carried out. Mathematicians were called in, and every movement made by the models had to be carefully calculated. Each boat was moved only a sixteenth of an inch at atime. A certain maneuver of the English fleet required eighty thousand movements of the vessels by.hand. Only sixty feet of film was required to record this movement, which took several days to carry out. Tiny chemical pellets were used to get the effect of a burning vessel. These were set off with a match. The gunfire was produced by blowing smoke through small tubes. The board upon which the battle was staged measured eight feet square. Each of the tiny models em- ployed was scaled down to the proper size. The camera used in taking the pictures was placed above the “‘battle”’ to get the effect of an aerial view BAA taf — PLEAS torn

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July, 1921 Teaching Tricks to a Dog It’s easy, but it requires infinite patience By Latimer J. OY RUSH, of the Ringling - Brothers and Barnum & Bailey Circus, can train a dog or a monkey in six weeks. In the “big- gest show on earth’”’ the audience sees a fluffy little dog balancing himself up- right on a slack-rope. The dog puts his fore feet upon the rope, then mounts it with his hind feet, and for an instant balances himself on all fours. At a word from his master he stands upright, cleverly keeping his balance on the swaying rope. How did he learn this trick? ° First he was taught to Wilson moving in a circle. After a few mishaps the monkey found that he could stay aboard by balancing himself, and that it was easier to keep his balance going around in a circle than in going straight. Finally the rope was removed and Joe rode around by himself. Three stakes painted white were planted in a row, and Joe was piloted by the guide-rope stand upright on the floor— an easy trick taught to many dogs. Then he was A dog, unlike a cat, does not naturally climb a ladder; the dog here shown was taught the feat by degrees made to stand upright on a large rope stretched upon the floor. Rush holds a thin light cane and speaks to the ani- mal in a firm tone, but with- out a trace of anger. A dis- play of anger spoils the work of days; for dogs and mon- keys are very high-strung, temperamental creatures, quickly responsive to the moods of people. When the dog had learned to stand up on the rope on the floor, the rope was elevated a short distance. Great patience was now required to keep him balanced. He _ soon found it more difficult to stand upright on the slack- rope than on a rope laid on the ground. After half an hour of failures the dog for a moment succeeded. Then Rush patted him. Occasion- ally after a successful exhibi- tion Rush gave the dog a small piece of meat, a lump of sugar, or something as a reward. In the case of Jocko, a big baboon, the reward was literally a ‘“‘chew of tobacco.” “How did you teach Joe [a monkey] to ride a bicy- cle?”’ I asked Rush. “Well, Joe was first taught to sit upright in a small chair. Then he was taught to sit upright in a little tri- cycle, his feet tied to the pedals. As the tricycle was pushed around the room, Joe learned the art of pedal- ing. Next he was placed on a small bicycle, a guide-rope attached to the collar around his neck. This guide-rope, which I held, kept Joe Monkeys and dogs are high-strung and tem- peramental. Their trainers must never show any trace of anger Each dog was taught his part of this ensemble trick; then the four were brought together for their act 29 so that he would circle around one after another. “Joe! Joe! Joe!’ com- manded Rush, pulling gently on the rope on the side he wished the monkey to travel. When the guide-rope was removed, he still gave the same commands, simply the word “‘Joe!’’ firmly uttered. He always stood in front and on the side that. indicated the direction to be followed. Finally Rush could stand in one spot and give the com- mands and the monkey would obey. He remembered what was wanted of him. Dogs and monkeys can be taught tricks when they are about a yearold. The train- er wanted to teach Joe how to juggle plates. First, Rush sat him on top of a tall stand and leashed the collar-rope so that Joe could not get very far away. Then four wooden blocks about an inch thick and five inches long by three inches wide were tossed at Joe one after another. At first the monkey warded them off to prevent them from striking his face. Rush continually commanded, *‘Joe—Joe,”’ each time throwing a block. At last Joe caught one of them, and Rush patted him affection- ately on the head. Within half an hour, after Rush had made about forty trips pick- ing up the blocks, Joe caught all four of them. The first attempt to teach him to jug- gle was declared finished. Joe was pat- ted and kind things were said to him. Then he was given a raw _ sweet

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potato. At this he grunted loud approval and went into his cage to enjoy it. There is no use telling a dog or a monkey in long sentences what is wanted of him. Call- ing merely his name, but in a tone of voice that demands obedience, is what counts. The tone of voice carries more weight than the meaning of what is said. The trainer should know from the start just what he wants his charge to do. Any uncertainty in his own mind only confuses the creature. Rapid success in training depends upon making the animal understand what is wanted by repetition until he gets it firmly fixed in his head. Later it becomes merely a mat- ter of memory and association. A good performance is asso- ciated with reward; a bad one receives censure in tones that are unmistakable. But there is no inhumane treatment; no exhibition of bad temper. Monkeys respond quickly to the instinct of self-preservation. Joe was riding his bicycle in a wide curve, and realized that collision with a box near the wall wasimminent. Ashe approached the box he threw out his arm and warded off the blow of im- pact. In this differs from the clumsy bear. bear would have ridden full force Photography Comes to the A HIRTY-TWO,” mumbles the tailor as he wraps a measur- - then he tackles another spot, and another. No wonder men hate to have their suits made to order. Now, however, with the aid of a camera and a chart, your measurements can be taken at two clicks. back to the camera and then you have your side view taken; from these two pictures the tailor makes your suit. The chart is built like a blackboard, ruled off with white lines two inches apart, running vertically and horizontally. The camera is always at a fixed distance from the chart, and you ing-tape around you; stand on a white cross in front of the chart. White tapes around the body aid the tailor in his calculations. How does the tailor calculate the actual circumference of your body at various places? He takes the front and side dimen- sions, adds them to- gether, divides the number by two, and multiplies the results by 3.1416—the num- ber in mathematics that denotes the ratio of the circumference of a circle to its diameter. particular the monkey No longer need you be measured minute- ly by the tailor; instead, you may have your picture taken against a chart and then let the tailor figure you out It required days of | endeavor to _ perfect this act. After each successful step the trainer rewards the animals into the wall without any attempt to save himself. Would you like to teach your dog a few tricks? Watch the dog- and monkey- trainer who has had a score or more years’ experience in training small ani- mals. There is just one thing that is A essential, and that is patience, without that, all hope of success is futile. First you turn your , 30 Popular Science Monthly Valuable Fertilizer Found in Austrian Caves USTRIA is a country of many caves. It has been discovered that in many of the eaves among the Salzburg Alps, especially the Dachstein and Tennen ranges, the floors were piled high with natural fertilizer. The origin of these piles of or- ganic matter is ascribed to the remains of the bones and excre- ment of prehistoric animals, most of which are covered with deep layers hundreds of years old of bat guano. Besides these masses of enormously rich fertilizer the earth beneath them is strongly impregnated with a readily solu- ble phosphoric acid. An expert declares that ‘‘the exploitation of even a small fraction of this fertilizer should produce material of sufficient value to cover Aus- tria’s entire war debt.” The Austrian government has passed a law declaring these masses of guano to belong to the government. Unfortunately, this material, in spite of its richness, cannot be delivered immediately to the farmers whose lands are crying for food, since it contains certain substances that are in- jurious to plant life. Chemisis and physicists must study the deposits to determine the best method of extracting the useful elements. id of the Tailor The back view and the side view are photographed and from these the tailor calculates your measurements eT ee =e mw — TH — ee r= —_ | | ~~ Re

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SS Oe eal ast Risse ak A July, 1921 To Tell One Typewriter from Another By Alfred Gradenwitz HE issue of many legal cases turns on the author- ship of a given sample of type- writing. Now, though by no means a hopeless task, the identification of typewriting affords incomparably greater difficulty than that of hand- writing. According to Profes- sor W. Scheffer, a microscopist who acts as legal expert in such cases, the first step is t§ ascertain the general type of -writing—Roman, Gothic, © italfes, imitation of handwrit- - ing, etc. Then comes a closer analysis, partly by means of the microscope. It should be considered, in this connection, that a given sample is the product of a num- ber of different factors. Apart How the letters of a typewriter appear under a powerful magnifying-glass. The examiner can bring out very small details of construction, valuable in identifying typewritten manuscripts. In determining typewriting the personal factor is im- portant —the varying strength and tni- formity of touch and the speed of the typist—and also the ribbon structure from the form of type, the mechani- cal arrangement of the type levers and letters and differences in the arrangement of the various letters of a given machine should be taken into account. Then comes the per- sonal factor—the variable strength and uniformity of touch and the 2. a a speed of the typist—and, finally, the structure of the ribbon, which is liable to alter the form of indi- vidual letters. In investigating the letter types of a machine, the expert can resort to one of two methods: He can inspect the types by means of a magnifying-glass, either in their natural position or after removing them. The second method, generally preferred in fixed-type machines, consists of removing the ribbon and substituting a sheet of high-class carbon paper. This will bring out How the small a looks on three different machines. Although they appear alike at first glance, the scientific examiner would be able to demonstrate their difference by actual measurement nan” man Words made on two machines of the same manufacture. The type on one alined perfectly, while that on the other did not. This is important in the identification of typed documents The spacing between the letters depends upon the mechanical construction of the typewriter. By writing upon this carefully . ruled surface, the difference in type spacing may be determined the most delicate details in the shape of the types. The A in most machines with a horizontal A-lever shows a de- cided tendency to strike double. When the A stands beside a letter with a vertically swinging lever, its relative position may be higher or lower, according as the typist is writing quickly or slowly or striking hard or soft, and the same may occur in connection with other letters. The relative position and alinement of letters, therefore, does not allow the kind of machine to be ascertained, though it may afford a useful clue as to the identity of the typist. Professor Scheffer also uses a special gaging process. On the basis of the dimensions of the cor- responding parts of the machine, as ascertained by the most careful measurements, in conjunction with measured samples of typewriting, he prepares a photographic grating into which the writing of a given machine fits exactly. If, now, the sample at issue, on being covered with the grating, is found to fit into it accurately, there is evidence of the sample having been written on a machine of the same make. Listening to Heartbeats by Radio HYSICIANS in New York city may now listen to their patients’ hearts beating in San Francisco. The heart produces a delicate sound that may be heard by a person placing his head on the patient’s chest. he vacuum tube that makes pos- The part of the apparatus shown above is used in magnifying the sounds of heartbeats. It can be connected with a distant patient and the heartbeats heard perfectly. A special telephone transmitter is laid on the patient’s chest, as shown at the left 31 sible the Jong-distance listening just mentioned is a new stethoscope. It amplifies the sound of heartbeats elec- trically, and they may be made so loud as to be almost deafening. A special telephone transmitter is placed on the patient’s chest. This is connected with several vacuum tubes that am- plify the current, so that it may be fed into a telephone circuit or a Jarge wire- less telephone-transmitting outfit. When medical men meet, the heart- beats of a patient may be made Joud enough to be heard throughout a large auditorium. Two hearts seldom beat alike (there is no sentiment about this), and medi- cal men can often diagnose certain ailments by simply listening to the heart action.

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Making Money Out of the Bamboo It rivals American sweet corn in flavor and grows at the rate of a foot a day By Captain H. P. Sheldon 3 vy “ao Sy GIANT grass four inches thick that grows a foot a 4 day until it is fifty feet high such is bamboo. Its sprouts rival our sweet corn in succulency and flavor; its towering stem will furnish timber to make furniture, fans, and fishrods, tent-poles, trel- lises, and toothpicks; its graceful outlines and green and golden beauty rival that of the white birch. Is it any wonder that the Bureau of Plant Industry of the United States Department of Agriculture encourages the cultivation of this fast-growing Oriental immigrant? You first encounter bamboo as an edible in that Chinese dish known as chop suey. It is a mor- sel of firm, wholesome texture and delicate flavor, cut from the tender sprout. Hitherto America has re- lied upon imported preserved bam- boo sprouts, but now we may have the fresh home-grown article direct from our own plantations. For the bamboo is already. flourishing in several American groves, the oldest of which is near Savannah. Another profitable grove is located at Avery Island, Louisiana. The plants were intro- duced first by a Cuban rice-planter some thirty years ago, and later, in 1902, David Fairchild, a plant explorer for the United States Department of Agriculture, succeeded in introducing other sprouts. The bamboo finds our Southern climate and moist soil friendly, and there now remains no question as to the adaptability of the giant grass in the Southern Atlantic, Gulf, and Pacific states. One plant will form a grove, for it grows and spreads much in the man- ner of its smaller cousin, asparagus. It needs no cultivation whatever, once it is established. An acre of bamboo will produce one thousand sprouts each year for forty or fifty years. A few days ago, Secretary of Agri- culture Meredith received a package of edible shoots from a Louisiana plantation that Mr.. Fairchild started. Mr. Fairchild, sponsor of the new industry, and perhaps better informed on bamboo than any one else in America, says this about bamboo culture: “The high food value of the bamboo shoots—about equal to that of the onion—their earliness as a spring vegetable, the fact that permanent plantations can be established and that the timber from the uncut shoots has an increasing market value, makes me confident of its successful introduction into American horticulture.” In preparing the shoots for the table the brown stripped off, the tender sprout sliced outer husk is Ao y ae “ ie Six years ago Rufus Fant planted a bamboo shoot on his property at Anderson, South Carolina. Here you see him standing in the grove that grew from that original plant Here are the shoots, ready to be cooked. They are cut into small pieces, boiled for an hour, and then served with a butter sauce lengthwise, and boiled for an hour in salted water. It 32 The small shoots have a delicious taste and are very healthful. Here you see a plateful of shoots that have had their husks re- moved. One of the shoots, how- ever, is still in the husk is served with drawn butter. A description of its industrial value would run into as many paragraphs as a treatise on the value of our native pine—but there is this difference: genera- tions of man must come and go while a pine sapling reaches ma- turity, but the bamboo achieves the same result in a space of months! Its hollow construction and impervious surface make it useful for drainage and water pipes and for any framework requiring extreme strength com- bined with lightness and -resili- ency. The long fibers are ex- tremely tough and pliable and are well suited for basket-weav- ing and barrel-hoop making, etc. The plant-loving people of the Far East have long recognized the peculiar, graceful beauty of the bamboo as a feature in their landscape grouping; its’ slender height, delicate coloring, and feathery foliage are unusual.even in a tropical landscape abounding in variegated plant life, and as a place in which children can play, no other spot can rival the deep green shade of a bam- boo grove. This chair is made entirely of bamboo grass. The grass is hollow, strong, and yet flexible; hence it is excellent ma- terial from which to make furniture

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nd na- July, 1921 Photography Becomes a Detective Two glass plates superposed show what paper has been taken from your desk UPPOSE that a complicated ma- S chine is to be drawn—a new type of locomotive. Suppose that the designing engineer modifies the con- struction from time to time. He changes the position of a connecting- rod here at one time, or the position of a lever at another time, dispenses with a gear, inserts a spring where there was none before. Perhaps it becomes nec- essary to make a new set of drawings. The changes indicated may be so slight that only by the most minute comparative study is it possible to determine what changes have been made. So, too, during the construc- tion of a huge office building or a bridge. What progress has been made from day to day? Mere inspection will not supply the answer. Mr. M. H. Stillman, of the United States Bureau of Standards, has de- vised a simple photographic method that makes it easy to spot these slight changes in drawings or structures at once. Take a stone wal], for example, a rather loose structure of almost in- What Stones Have Been Shifted in this Wall? Here (on the left and on the right) are two photographs of the same stone wall taken at different times. A few stones have been mis- placed and a soft felt hat placed on a stone was removed before the second picture was made. Study the photographs and see if you can detect the difference. The hat will help you. Look at the black photograph just below and you can detect the changes at once The Telltale White Streaks and Spots From one of the negatives of the two photographs appearing at the top of this page a glass positive was made. This positive was placed over the other negative so that all details registered. Where they do not register, white streaks and spots appear on the print here repro- duced. These white streaks show what stones have been displaced or removed. A soft felt hat, for ex- ample, was removed after the first photograph was made. It appears as a white spot on this picture discriminately piled rocks following a general line. Suppose that stones are added or removed. Mr. Stillman makes a photograph of the wall on one day and then another photograph on some following day. From one of the negatives he makes a positive on glass. This positive is placed exactly over the other negative and a print is made. At once the changes are revealed by either dark or light patches against a uniform background. If no changes have been made, the light portion of one plate registers with a corresponding dark area on the other, and conversely. When changes have been made between exposures, the lack of correspondence between the dark and light regions of the positive and the superposed negative are at once apparent. It is readily appreciated that by this method hours of pains- taking labor can be saved. Apply this method to a _ desk laden with papers and books. You can tell at once whether any one has shifted them about or removed some of them. It is often useful to follow the progress of a building in the The first and second photographs were made at different . bd =! } Ea course of construction by showing the amount of work’ times. The third photograph, made in accordance with done during any interval of time at the beginning and end of which photographs are taken. shown in these three photographs This application is the principles explained in the article, indicates by means of the white spots what changes have taken place between the interval when the first two photographs were made

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Popular Science Monthly The Tractor as a Stump-Puller EW uses for the farm tractor are con- stantly coming to light. The picture above shows an Iowan farmer pulling up a small tree with his gasoline tractor. When the driving wheels are properly shod to give positive traction, the machine makes short work of hauling the trees up by the roots. During the war, when dynamite was un- obtainable, the resourceful tractor owner decided to press his machine into this service, and now he would not think of ridding his land of stumps or trees in any other way. It is much cheaper and safer than dynamite. It is a constant source of wonder to farmers how they managed to get along before the tractor was invented. Certainly they had to work harder. Resuscitating the Drowned by Machine 6 resuscitate persons who have been drowned or who have been otherwise asphyxiated, the chest is rhythmically compressed. Sometimes the victim of asphyxiation dies because the would-be life-saver is ex- hausted and is forced to give up his efforts. A German physician has now invented a machine that makes it possible to continue attempts to induce breathing for an in- definite period without placing a strain on the opera- on its sup- tor. The as- porting base phyxiated from a hori- person is placed upon a_ stretcher and __strap- ped to a sup porting cushion by means of canvas breeches. The stretch- er is tilted zontal to a vertical po- sition and the compression of the lungs is brought about by the changes in the position of the body in tilting. Paddles Made of Metal for Swimmers gpemgersaetige edd of Roman conquerors are these shield-shaped paddles. But they are not intended for the gentle art of self-defense; they are meant to increase a swimmer’s speed, in emulation of the webbed foot of the duck. It is very simple to understand that a flat surface, not too heavy, will offer a more effective resistance to water than the hand, and that a person would be propelled through the water with much greater speed by using these paddles. They are made of tin or aluminum, the rolled edge giving the needed strength. On the under side are two loops, also of metal, through which the first and third fingers are thrust. If you would like to increase the power of your swimming-stroke, here’s your chance. Harnessing the Wind yo ago, wind power was commer- cially possible. It simply had to be, since there were few other sources of power. Today we get most of our power from coal and a great amount from water. Palestine is not favored with either coal or water power, and Dr. I. M. Mayersohn is now studying the problem of wind power to determine whether or not it will be possible to run the industries of Palestine with wind-motors. He has collected inter- esting data on wind motors in Europe. Examination of four hundred and- seventy- seven installations was made. Eighty-seven per cent of these had worked satisfactorily for periods up to eighteen hundred years. Wind-power in- stallations are now made in Denmark for the gen- eration of electric power in small communities. 34 Trailers for Limousines Pa Ave you noticed that the trailer has left the farm and gone to the city? It appears nowadays behind the limousines belonging to the very best families. In shape it resembles an ancient chariot. What is it used for? Carrying trunks, suit- cases, and other pieces of luggage. People with limousines are always going some- where. The trailer has solid wheels with hard rubber tires that are well able to stand the strain caused by heavy trunks. Each wheel has a corresponding mudguard that keeps the trailer clean. Usually this very useful accessory to automobile equipment is painted to match the limousine with which it is used. Note the strong coupling-bar that connects the trailer with the limousine. Buy a Cabinet for Your Small Phonograph Least you buy a phonograph, the price is governed as much by the case as by the mechanism. As a result, many people buy cheap cabinetless phonographs at first, and then wish later that they had not been so economical. Now they are able to buy empty cabinets into which they can drop their small machines. The woman in the picture is shown placing her machine in one of these cabinets. One advantage of this idea is that the phonograph can easily be moved. a! Se) a” a!

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OD Gl OO SS ts Se ait \ July, 1921 It Stops Boiling when the Coffee Is Made “TS the coffee done?” That’s a hard question. to answer. Now, however, there is a coffee- pot that stops functioning when the coffee is done. The pot is divided into two sections, separated by a metal partition. Through its center runs a tube, and at the top is a compartment resembling a per- colator. The water is placed in the lower compartment; as it is heated it rises in the tube, flows - through the coffee, and drops into the upper compartment. This process continues until there is no more water in the lower half—the coffee is done. Of course you must be on hand to remove the pot from the stove. A Bird’s Nest Built in a Pair of Shears S Bee: tiny Bewick’s wren who built the nest below chooses to dwell near farmhouses in many parts of America. Sometimes it will build its nest in an old straw hat hung in an out-of-the-way nook, a_ rusty bucket, or an old shoe, and one nest was seen in a tin can that lay in a barrel of trash in a farmyard. The nest here shown was made of hay, weed stalks, and feathers. It was placed between the blades of the shears that rested on a rafter. Aside from the music with which these diminutive birds please all listeners, they rid gar- dens of some of the worst pests to agriculture, and boys should be taught not to destroy them. Each Motorist Ferries Himself To is a ferry-boat on the Thames, England, that has no Charon to guide it from one bank to the other. It was built to enable motorists to get across without taking the usual roundabout trip, and it is operated by the motorist himself. The boat measures fourteen by twenty feet, allowing plenty of room for even very large cars. , It has in its side a slot through which a chain passes. This chain runs from bank to bank and fits over the teeth of three cogged wheels. A large fly-wheel operated by the motorist himself, as shown in the picture below, sets these cog-wheels in motion, and as a result propels the boat across the river. Suppose the boat is at the other side when a motorist wishes to use it. There is a winding wheel at each bank that enables him to draw the boat toward him. Butting the Coal-Cars no butting coal-cars up an incline, a big railroad uses a mechanical billy-goat. The “goat’”’ is attached to a long cable, which is wound upon the drum of a power- ful hoist. This hoist does not even groan when it is pulling up a 60,000-pound load. It is sheltered in the shed over the trestle. When the car is emptied, the billy-goat escorts the car down the incline. When the bottom is reached, it lets go and suddenly drops into a small valley between the tracks, the empty coal-car rolls on, takes a flying switch, and goes over to the empty track. The Lincoln Highway’s Surfaces oer highway from the ‘Atlantic to the Pacific, open to lawful traffic of every description’’—this was the plan of the originators of the Lincoln High- way. In pursuance of this plan, in seven years’ time $31,284,520 was spent in im- proving the road. It is interesting to note that the builders have used the most suitable material for the various sections of the country to be served, and that there are no fewer than twelve types of surfacing employed, beginning with 422.34 miles of concrete, and ending with 3.3 miles of sand. American Fruit in China 6 per quarter of all the people in the world live in China. And there is not enough fruit in the country to supply them all. Hence Japan and the United States are both selling fruit there. In the picture below you see a fruit-store in Peking. The fruit has been arranged to good effect by the three smiling ven- dors. Apples, oranges, lemons, and grapes that were grown in the United States are sold there. Until recently the people of the upper classes were the only ones who were able to buy fruit. But the wage- earning ability of the Chinese laborers has been slowly increasing of late years, and American growers anticipated an ever- increasing market in China. But, alas, for the poor Chinese, the failure of their own crops will prevent them buying anything more than the merest necessities for some time to come. aa &\ ARABS PMSURRSAL FARRBAS! 3 med a

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Sets _ are used. Popular Science Monthly Back and Forth as It Sharpens the Blade SUALLY it is when a man is in the greatest hurry to shave that the razor-blade is found to be dull. That is the time the little sharpener shown above will come in handy. No leather or rubber belt or wheels The blade is clamped in a little vise and the sharpening substance is moved back and forth over the edges. The sharpening element slides on a small rod mounted over the razor- blade. A few strokes of the sharpener will put a dull blade in fit condition to shave a king. And a man no longer You Can Stick Pins in This Self-Healing Rubber Ball ERE is a ball that is bullet-proof, pin-proof, and dog-proof. It is made of very live rubber with a light coating or skin like that on any other rubber ball, while the interior is made of spongy rubber. A glance at the above picture will convey an idea of what the ball will! stand. If the dog gets the ball—as dogs often do—and chews on it for a while, no harm will be done. A ball inflated with air will not stand such abuse. A tiny pin- hole will allow the air to leak out, and the ball at once loses its resiliency, at the same time losing its value as a play- has to remember to take those old blades to be sharpened; he is now in- dependent ot outside help. An Adding-Machine for the Blind N attachment for an adding-machine 4% has been invented, with the result that the blind can very easily learn the tricks of such a machine. The original design is the invention of a blind man, J. R. Oastler, and all of the necessary details have been worked out under his instruction. The in- vention is an attachment that can be added to a standard portable machine and is in the shape of an auxiliary set of keys. The keys are alternately concave and flat, and the operator works easily and quickly, his fingers flying over the keys as if he had perfect sight. The usual glass over the numerals has been removed and the original figures fitted with the Braille system. One Engine for Cultivating and for Churning ICTURED above is a garden cultivator that not only cultivates all garden crops, but that also churns, digs potatoes, serves as a cream-separator, mows lawns, pumps water, and runs a grindstone! It weighs two hundred and eighty-five pounds when fully equipped. Its engine develops two horsepower and runs from four to eight hours on one gallon of gasoline. As a cultivator it is guided down the garden where the rows are twelve inches or more apart. It can work between rows two feet apart. and can be converted into a lawn-mower. Beware of Argentine Ants RGENTINE ants are such pests that when they decide to invade a house, two minutes after the table is set, it may look like the one below—completely overrun! In spite of their South American name, these ants are found in the United States— they were introduced years ago on coffee ships landing at New Orleans from Brazil. If tape is soaked in bichloride of mer- cury, dried, and then wound around the legs of chairs and tables, the ants will go elsewhere. thing. This unpuncturable ball, or rather, a ball that heals itself, is very popular. The Weeping Doll eis you have tears, prepare to shed them now,” says Mary to her doll. Where- upon she squeezes a bulb that is concealed in the doll’s back, and two large tears gush forth from the doll’s eyes. Such is the new crying doll recently in- vented by George J. Hoefler, of Stapleton, New York. The doll’s head is entirely hollow and watertight, except for two small holes in the eyes. A large cork fits in the neck and through it runs a tube that terminates out- side the doll’s body. A bulb is attached to the end of thetube. Thus, if the doll’s head has a few inches of water in it, drops will ooze from the eyes when the bulb is squeezed. \ \ ea : - Wee af

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July, 1921 This Fountain-Pen Winds Up Like a Clock HIS fountain-pen “winds” up like an eight-day clock. It will draw a line two miles long before its supply The Red Cross Above the Ship FA OSPiTAL ships of to-day must wear a red cross not only on the side and stack but on top. This is to guard against attack by hostile air- craft. In the picture below you see the large cross of the U.S. S. Relief, an oil-burning hospital ship. By day its coat of brilliant red paint makes it plainly visible from above, and at night it is constantly illuminated, as are the red crosses on the side of the ship’s hull and smokestack. The ship is four hundred and eighty-five feet long and has a beam of sixty-one feet. There are eight decks in all, and they are connected by three elevators. The laundry on board will handle ten thousand pieces of wash a week, of ink becomes exhausted. It requires a lot of writing to make a line a mile in length. The ink is drawn into the pen in a new way--it is pumped in. A little red handle at the end of a piston is pulled in and out several times until the reservoir of the pen is full. Fountain-pens in general have caused a lot of swear words to be “sworn,” but this little pen has taken its place among the better behaved pens that write when you want them to. Clasp the Grafted Bud HEN a bud is grafted to a tree, the resulting wound must be bandaged until it heals. But this bandaging process is diffi- cult and slow. Vincent Tollis, of Clifton Springs, New York, has invented a “‘budding-clasp” that is operated with all the simplicity of a clothespin. It is made like the familiar spring-clasp clothespin—the grooved sec- tion clasping the young tree instead of the clothesline. This section is hollowed out to accommodate the bud, and the ends of the spring are firmly joined. , To Save the Lives of the Children of France gaia the war the French government has issued almost hysterical appeals to the populace, offering prizes for large families. This has had some result, but not nearly enough. Why? Because the question of infant mortality was not taken into consideration, and apparent gains were short-lived because nullified by the large death rate among children—from 15 to 20 per cent in children in their first year. It is the statement of a high medical authority that by cutting down infant mortality France could add one hundred thousand to its population yearly. The more intelligent of the population is asking, therefore, what is the use of rearing large families if their lives are not safeguarded by the utmost efforts of the government. In response to this question, the Minis- try of Health is making distinct efforts to give mothers better care, and to surround new-born infants with every pessible pro- tection against disease and death. This, in our opinion, is the right track—salvage rather than mere production. 37 ! a } PACKING? {RING NOTCHES KB | | BODY _ Hi (4.5 SHELL u | They’ve Found a Use for Old Shells ILLIONS of shells of all sizes were left over from the war. An Englishman has invented a small hydraulic jack that can lift ten tons. It is made from a 4.5 high-explosive shell, and the ram from an eighteen-pound shrapnel shell. The detachable head of the 4.5 shell is divided into two pieces just a little forward of the shoulders that normally screw on to the body. The portion that screws into the main body of the shell is bored out to a suitable diameter and re- placed to form a gland and guide for the ram. - Twisting the Wire’s Tail VERYBODY is familiar with those flat pieces of cardboard or wood that can be transformed so quickly into boxes. Some of the boxes are bound with wire. This wire must be fastened securely together at the ends. While a pair of pincers would serve, the resulting twist is easily undone. Knowing this, S. F. Bauwens, of Rockaway, New Jersey, has invented a wire-twister resembling a _ brace-bit in form, but in place of the bit is the twister, with jaws to engage the wire, and cut it, after which the twist is pushed down flat.

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Use a Headlight at the Piano ERE is a headlight that is literally a head light. It is a light that you wear on your head. The wires and battery are concealed in a bandeau worn around the forehead, and the light itself stands out in front. This lamp was probably invented after the idea of the miner’s lamps, that has also been adopted by physicians, surgeons, and dentists, its especia! value to them being that both hands are free. Thus you are provided with a flash-lamp that does not have to be held in the hands. The picture above shows a girl playing the piano by the light of her lamp; she is well able to see the keys and music, although the rest of the room is dark. An Electric Light for the Use of Firemen ITH his old oil lantern, the fireman always took a great chance when he entered a gas-filled room. An explosion might occur. The fireman’s little electric flashlight shown below is perfectly safe in every way. The switch is conveniently located near the handle. The beam of the light may be spread or concentrated. When working in dense smoke, the beam may be concentrated to give it the proper penetrating power. It is safe to say that these electric lan- terns will before very long entirely displace the old oil lanterns that are seen to-day, even on the most up-to-date fire-fighting apparatus. The life of a fireman is perilous enough, and his equipment should include only the best. ON AND OFF Carry Your Bath-House with You IVING in a country of five hundred lakes, Virginia W. Collier thought: “Why can’t I invent a portable dressing cabinet?” Here was a real automobile need. Her first thought in the plan of folding and of carrying the cabinet compactly was sug- gested by a box-kite. From this idea she developed a similar structure that would stand on end, firmly planted by its spiked uprights in the ground, with an X at the top to give it support and maintain its form. Then came the task of making the uprights jointed so that the whole structure would fold into smaller dimensions. This resulted as in the cabinet shown, the whole folded and carried in a case the length of half the uprights. Where Your Time Goes Seon man accomplish much in his three score years and ten? Some interest- ing calculations have been made to find out what a man does with his time. Basing these calculations on sixty years (counting out the first ten years of life as the period in which the subject receives more or less help in these duties), somebody with a flair for figures has made the chart below. The average man, according to this chart, spends 11 months in dressing; eating, 5 years, 5 months; working, 16 years, 8 months; sleeping, 21 years, 8 months; he spends 7 months in church. The chart even goes into the details of tooth-washing and shaving, and arrives at the conclusion that there is left for pleasure 8 years and 11 months. Popular Science Monthly She Boils Potatoes in Her Hat HOULD your hat be made of non- inflammable material, you can use it to cook your lunch in, says the woman in the picture above. She turned her hat upside down, filled it with water, and placed it over a small alco- hol stove. When the water reached the boiling-point, she dropped in two potatoes. Later she added some eggs. When eggs and potatoes were cooked, she emptied the water out of her hat, wiped it dry, and put it back on her head. Her lunch then was ready. Of course, the hat is made of fireproofed material. Would it not have been easier, though, for her to have carried a small pot with her? Buried in the Air on the Island of Vancouver N a small settlement on Vancouver Island, the natives used to bury their dead in a singular manner. “Bury” is hardly the word, since the corpse was not put below the ground, but was elevated high above the ground, on or in a column of cedar. m Besides the moss-covered figure at the top of the pillar, a corpse may also be found resting inside the door at the back of the carved figure, and there is another corpse in the panel below. According to the natives’ belief, these poles were set up as protective fetishes in their lifetime, and, very consistently, they chose them as a safe resting-place after death. Today most of the natives of this tribe follow the Christian religion.

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July, 1921 A City Advertising Idea in the Country “TOR SALE.” When you hang up _£ this sign in front of your house, the people who pass by are the only ones who will see it. And if your house is on a quiet street the chances for selling it are not good. A Los Angeles man found himself in this predicament—his house was on a hill about three blocks from the main road. What did he do? He bethought him- self of city advertising displays, where the need for standing out from sur- rounding high buildings has induced ad- vertisers to use the roofs. This man built a ‘‘for sale” sign out of boards and erected it on the roof of his house. The letters were painted white, and since they were four feet high they could be plainly seen from the main road. Hams Smoked the Modern Way LD-FASHIONED smoke-houses in which pork was either cured or burned up with the house are being replaced by a less dangerous and more sanitary smoking- stove. This stove is made of metal, and is mounted on wheels. It has a large oven in which the hams, bacons, and sausages of ten hogs can be cured at one time. Beneath the oven there is a drawer in which cobs and bark are burned. The smoke rising from the fire passes through cooling tubes into the oven, and out the chimney. After sixty hours of this smoking the pork is completely cured. CHIMNEY~p 4 COOLING RADIATOR Both a Weeder and a Cultivator HIS device, a big help to the small farmer, is a weeder that cultivates as it weeds. It is adjustable in width, so that it may be used between rows of plants placed any reasonable distance apart. The weeding teeth are attached to two arms which may be adjusted to any angle. As the teeth pull through the ground they turn the earth over, and also pull the weeds up as they go along. The teeth of the weeder-cultivator are tilted in order to overcome the tendency to come to the surface as the weeder is pulled along, Acetol, a New Motor Fuel ETROLEUM is not going to last forever. The supply is now getting low. Other sub- stances may be used, but it has not been necessary to de- velop the other sources while there is plenty of gasoline. Far-sighted investigators have been at work on this problem for a long time. S. W. Blake, an English experimen- ter, has developed a fuel which he calls acetol. Acetol is added to a mixture of alcoho! and acetylene. It increases the absorbing power of alcohol for acety~ lene from three to four times. It may be added to alcoho! in any proportion and in this way a fuel suited for almost any purpose may be prepared. The inventor proposes to obtain the alcohol used from the sweet potato, which can be cultivated very easily. 39 FOR HOOKS AND LINE HOLLOW HANDLE Giving Trees a Start in the World Scientifically EPOPULATING denuded forests is a job that falls to the United States Forest Survey; and it is done in the following manner. The seedlings are kept in a nursery during the first two years of their lives; then they are trans- planted to the ground. In the picture above you see the trans- planting process. The young trees are placed in grooves in a board that is seventy-five inches long and that will accommodate fifty young trees. When all the grooves are filled, a second board is snapped into position over the first one, and the entire thing is put into a furrow in the ground. As the young trees grow, the boards gradually sepa- rate, and thenceforward the trees are left to shift for themselves and get on as best they can. Combined Cane and Fishpole IMPLY unscrew the handle of the cane shown below, take from the hol- low interior two sections of rod, attach them to each other and then to the end of the cane, and you have a fishing-rod. On the large handle there is still a smaller handle. By turning the small one you open two doors at either end of the large one and take your tackle and worms from the hollow cases within When your fishing is over, you simply | replace your rod in the cane. Joe Kozlowski, the inventor of this fishing-pole, is a Pole himself, and he lives in Toledo, Ohio. If you happen to be both a fisherman and a cane-carrier, then you will be able to appreciate this invention.

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Popular Science Monthly Twenty Minutes with Edison on the Typewriter ERSISTENT rumors have been afloat that Thomas Edison invented the type- By Raymond Francis Yates certainly marvelous the way the typewriter manufacturers writer. As a matter of fact, credit for this should go to C. Latham Sholes, who started his experiments on a “‘writing- machine” in 1867. Nobody is more anxious to have this matter straightened out than Mr. Edison. Sholes was not the first man to conceive of a typewriter, but he was the first man to “‘reduce it to practice,’ as the patent attorneys say. It was in a dingy little machine-shop in Milwaukee that Sholes and his associates developed the typewriter. It was no small job to build such a machine in those days. The alinement of the keys and the shaping of the parts was a stupendous job. Six years of hard work brought the typewriter to a usable state. It was a big, clumsy thing, but it wrote, and wrote fairly well. Sholes made a brave attempt to manufacture and market the machine. He spent every cent he had in the world. A man by the name of Densmore helped Sholes in his struggles and bought an interest in the patent. Finally, realizing that the venture should be placed in the hands of a big manufacturer, Sholes and Densmore made an agreement with the Reming- tons, at Ilion, New York. From that Here is Mr. Edison posed beside the first practicable typewriting machine, which he says he did not invent moment the typewriter swung into commercial life. A few weeks ago I called on Mr. Edison, lugging into his office the original Sholes machine, which I had borrowed from the Remington Com- pany. I wanted to ask the “Old Man”’ some questions. “Do you recognize theold machine?” I asked. “Yes,” hesaid. “It is the same type I worked on. I remember the hard time I had getting the keys in aline- ment. That was a nasty job. It is Two or three of these tourniquet-belts will hold splints in place when an arm or a leg is broken. One of them may also be used as a sling to support the injured arm A Belt that Is Also a Tourniquet (Right) The first step is to hook the ends of the belt to- gether above the injured part of the body; in this case it was the man’s arm (Above) With a quick jerk of the hand the lever is swung over to the locking po- sition. Once locked it~ will hold until the lock is opened 40 get the keys in perfect aline- ment to-day.”’ “T understand Mr. Sholes called on you years ago. Did he come to you for advice?” ‘‘No, Sholes did not come to me for advice. He simply called as a brother inventor. Sholes was a remarkable man. I believe it was back in 1873 that he called on me.” “Mr. Edison, do you know that some people credit you with the invention of the type- writer?”’ I asked. “That is wrong,” he replied with emphasis. ‘‘Sholes in- vented the typewriter, and he deserves all the credit he gets. Most inventors don’t get the credit they deserve,’’ he added. “T did practically nothing to improve the machine —al- though I built twelve of them for D. H. Craig, who had obtained the right to manufacture them from Sholes.”’ “Do you believe that we will ever be able to simply talk to typewriters and have them respond with automatic writing?’’ I asked Mr. Edison. “No, I don’t,” he answered. “A sound-controlled typewriter would be operated by the sound waves produced by the human voice, and since no two men would set up the same disturb- ance, I believe it would be a very im- practical arrangement.” (Below) Next, the belt is pulled tight. It passes over a_ roller which is part of a locking lever; hence it is pulled in the direction from which it comes (Left) The tourniquet is so strong that it can be used suc- cessfully over a shoe, provided the man apply- ing it has suf- ficient strength isn, #soe

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July, 1921 Electricity is at last replacing steam in the driving of trawlers. generators, which in turn, supply the current to electric motors that propel the ship Diesel engines drive electric You See Here the First Electric Trawler HE first electrically propelled trawler has been built. It carries two large and powerful Diesel engines, which are directly connected with two generators. The generators, in turn, supply current to an electric motor, which drives the trawler. This motor is connected with the propeller-shaft, and it may be controlled from the pilot’s cabin, where the necessary switches are located. From this point the boat can be started, stopped, and reversed. The driving motor is a 400-horsepower machine that pushes the clumsy boat through the water at fair speed. The reader will probably wonder why the boat is not propelled by the Diesel engines direct instead of using them to turn electric generators, which then supply the driving motor with power. Of course, engineers are forced to admit that some power is lost in this transformation of energy, but to offset this they are able to point out advan- tages that make it worth while. Flexibility of operation is one of the advantages claimed. The trawler may be reversed from full speed ahead to full speed astern in a few seconds with the electric drive. This may be done from the pilot-house. Smaller electric motors may also be 41 used on the cranes and hoists for han- dling material. This speeds up the handling of material, and in the case of the trawler this is important. All of the big battleships that are now being built in this country are provided with steam-electric drive. In place of the Diesel engines, which are not built large enough for this purpose, and which are unsuitable for other reasons, steam turbines are used. These are connected with big generators, which in turn drive the large 8000-horsepower motors connected with the four pro- peller-shafts. The steam turbines produce 40,000 horsepower.

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Popular Science Monthly Is It a Diamond or a Piece of Glass? Every young man should learn these tests “Let me see some dia- mond rings,” says the brave young man below. He chooses a_ beautiful stone —but how can he be sure that it is a real dia- mond? Let him try some of the tests shown on this page If the merchant objects to your giving the diamond rough treat- ment, try this: Look at a black dot on white paper through the A real diamond is so hard that practically nothing will affect it. You can warm a diamond, cover it with borax, and drop it in cold water. It will come out un- scarred; an imitation diamond, on the other hand, will break in pieces diamond and a piece of glass. If the dot seems blurred or ap- pears as several dots, the ‘‘did- mond”’ is a fake A drop of wa‘er will retain its globular form when placed on a real diamond; you can move it gently with a pin. It will spread if the stone is counterfeit Here’s another way to test a stone in order to see whether it is a real dia- mond or not. Drop some hydrofluoric acid on the stone; an imitation dia- mond will dissolve eriecgcss Scrape a nail-file along the edge of a diamond. What happens? Nothing, if the stone is d genuine. An imitation stone, on the other hand, would soon show the scratches Drop a diamond in water. You can see it plainly; that is because its index of refraction is so different from that of glass and of water. A glass stone would be barely visible 42 Ff a a. ne | ae tae

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July, 1921 an entire street is slowly sinking beneath the surface. The earth is settling into the cavities that are located hundreds of feet below. This settling or readjust- ing process will re- quire many years Here

Brick buildings are more sensitive to changes in their foundation levels than are wooden build- ings. Some day this big church will go down in a mass of dust and broken bricks and glass. Already great fractures can be seen in its side where the body of the church joins the tower

These buildings have suffered badly. In certain parts of Scranton you may wake up in the morning and find the door- and win- dow-sashes sprung to such an extent that they cannot be moved up or down

They Built Their Houses on Coal-Mines And this is what happened in Scranton

a fe -* f 4 " mF “< . Pe! y oh ; ‘ ag! be ee!

A total wreck! Here the buildings are reduced to a mass of splin- tered wood and stone—a property damage costing millions. seems to be nothing to be done to prevent further loss There Mother Earth respects neither homes, churches, nor ceme- ceries. Here is a vault gradually sinking to its doom. Within a few months it will be out of sight. It stands over one of the ex- hausted veins of a once prosperous coal-mine 43

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Speeding Up the Hairdresser AIRDRESSING has not escaped the efficiency net, and recently a number of tests were given in a school for hairdressers, the object being to speed up that occupation. The tests proper were preceded by a written test to ascertain the pupil’s mental elasticity aside from her pro- fession. Then delicacy of touch was tested by means of what may be described as an “elastic scalp.”’” This was done by asking the candidate to comb strands of hair suspended by the most sensitive elastic springs. Any pull at the scalp was registered by an elec- trical recording drum. Another apparatus recorded the number and adequateness of those turning motions of the wrist, which are of paramount importance in waving, their rate being gaged in fractions of a second, while the maximum possible angle of rotation was read at the same time. Another attachment recorded the number and degree of uniformity of the minute vibratory motions in the use of curling-irons. The point aimed at in any case is an imitation as close as possible of the actual process, no special training being required. In order to test the pupil’s ability to perform coordinate movements with both hands, she was asked to This machine, used in testing the efficiency of prospective hairdressers, is called the ‘‘elastic scalp.’’ Strands of hair are suspended by very sensitive elastic springs, and the motions of the person combing the hair are registered on an electric drum An attachment for recording the minute motions followed by the hair- dresser in using curling-irons Popular Science Monthly thread a number of wooden balls on a rod in a given order as quickly as possible, the time of performance being registered. The accurate simul- taneous motion of the two hands, so important for handling the comb and curling-irons in waving hair, was tested by asking the pupil to perform with both her hands certain pre- scribed motions indicated by a chart, any deflection from the pattern being checked. Resistance to fatigue of the arm and hand muscles was ascertained by ergometer tests, the possibility of compensation by practice being ex- amined at the same time. The re- tentive powers of the mind, most of all the taking in of visual impressions shown in rapid succession, is tested by special experiments. The discern- ing of delicate color shades is also ascertained by asking the pupil to sort strands of hair, while her per- sonal taste and sense of form are gaged by having her pass on a number of patterns. The apparatus and processes above described have been found to yield invaluable services in connection with the training of persons wishing to follow the profession of hairdressing and passing the initial tests for aptitude. Register Important Documents on Moving-Picture Film “ OUNTY courthouse burned to the ground; valuable records lost.”” With nearly three thousand county courthouses in the United States, it is not surprising that this announcement appears. repeatedly. What about those valuable records— deeds, mortgages, marriage licenses, land titles, birth and death certificates? They disappear completely. Now, however, a system has been devised for keeping records of these records. Photographs of the records are taken on a moving-picture film, and the film is filed away. If desired, enlarged prints can be made from the film and duplicate record books kept. A thousand volumes, containing six hundred pages of records each, can be photographed on a film, which, when wound up, will measure but eighteen inches in diameter! The photographing machine con- sists of a glass-topped table under- neath which the deed to be photo- graphed is held in place by springs. The camera is mounted on a frame at the back of the table. It is placed so that the lens points down and is directly over the table-top. The camera runs on tracks and can be moved up or down, according to the size of the picture wanted. Electric lights and reflectors are placed on both sides of the table shining on the glass- covered record. The camera is loaded with a reel of moving-picture film that is operated by acrank. It holds two hundred and fifty feet of continuous film, which is enough to photograph six thousand pages of records. The film of each This is the machine that photographs important records on a roll of film 44 That small roll of moving-picture film she holds in her hand contains nega- tives of all the pages in the seven large record books. Should the volumes be destroyed, duplicate pages could be made from the film volume is placed in a metal box, labeled, and sealed with paraffin. The box is then placed in a vault. Should the original records be lost, burned, or stolen, prints could be made from these films that would show every mark, erasure, signature, and indentation that appeared in the originals.

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10 QD & 1 PM b&uO Cs tf oT \X, he st, be ld "e, he July, 1921 Rival to the House-Boat HE house-boat has a rival in the new house-car; both can be moved with ease from place to place. The house, as you see, is mounted on an automobile chassis. When you feel like moving to a new location you throw her into gear and step on the gas. No landlords, no land taxes—an ideal condition! : The house-car shown was built by a Californian. He and his family of five live in it all the year round, moving A family that lives all the year in their house-car. It is electrically lighted and heated. When the family wishes to move, father cranks the engine Photographs © Kadel & Herbert This is the kitchen end of an auto- mobile house. There is running water in the sink and oil in the stove. Bedroom, living-room, and dining-room are interchangeable from place to place when they want a change of scenery. The bungalow is electrically lighted and heated and has a com- plete plumbing system. The driver’s seat can be made up into an upper and a lower sleeping- berth. The other mem- bers of the family, three in number, sleep in one large room of the bunga- low. This room can be changed into a dining- room, a kitchen, or a living-room. There are plenty of cupboards and lockers in which to hide things when they are not being used. Couple Up the Trailer as You Go AVE you ever watched the little tractor that goes around on the freight-house floor, picking up the trailers loaded with boxes, packages, barrels, or crates? To couple on these cars it was necessary for a man to follow. the loaded train, doing the coupling by hand. Now this work can be done by an autematic coupling device. The driver backs his train up to the car that is to be coupled on, and the iron tooth of the coupler jaws snaps down over the coupling bar of the trailer. The work is done more rapidly than by hand. As the train of “picked up” cars moves to the spot where all the cars are to be left, the driver merely operates a lever, which uncouples the first car, leaving the string of cars where de- sired. A man with an iron bar uncouples every other but the last ear. COUPLING-. _LINK trailer is an iron bar so bent that it is readily seized by the eoupler of the motor-car, or the opposite end of a trailer. The automatic coupler itself consists of an upper and lower jaw. A hooked “tooth” held by a strong spring clamps down in a slot in the upper jaw. A chain attached to this “tooth” connects with the lever at the driver’s seat, and by it the clamp can be readily raised to release the coup- ling-bar of the first trailer. | CHAIN TO |OPERATING L \(TO UNCOUPLE) The automatic coupling device is at the rear. It is attached to one end of each trailer car. At the left is shown how the bent clamp, or ‘‘tooth,” operates 45 This welding-machine will weld the bottoms in metal pots of any size diameter Welding by Machine NEW development in electric welding is a welding-machine with electrodes that rotate. This machine will produce a continuous weld on metal kettles and pots of various sizes. Continuous welding met with little success before the introduction of this machine. The trouble is eliminated in this machine by separating the weld- ing from the feeding motion. [he motion of the revolving elec- trodes is intermittent. The weld made is allowed to cool before the weld is continued. In this way a series of welds is obtained that produce a con- tinuous seam. With the machine illustrated, kettles of various sizes may be accommodated without any changes in the adjustment of the mechanism. A “Wireless-Wire” System of Communication T has been found that a wireless or Hertzian wave will follow a conducting medium when it is given the opportunity of doing so. The Telefunken Co., of Germany, has developed a commercial system of communication in which the high- tension transmission lines are used to guide the radio waves from one point to another. It will be understood that the waves are not conducted by wires in the usual sense of the term. The wires merely guide the waves and cause them to follow certain courses. This is done while the lines are carrying very high voltages.

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E have just come to realize that coal is valuable for no less than seven thousand substances use- ful to society.¢ Only one tenth of the product is converted into these thousands of invaluable compounds, which means an annual waste to the United States of two billion dollars of coal by-products. The Koppers oven is the latest for decomposing coal into its crude com- ponents, from which about seven thousand compounds may be obtained. Each oven has a capacity for ten tons of coal, which is carbonized for about twenty hours. Batteries of ovens are arranged in series, daily consuming thousands of tons of coal. The coal is fed into the ovens by a charging wagon, which runs on top of the setting.

How the Ovens Operate The hot gases from the ovens pass via ascension pipes into a dry collecting main and through water-coolers at a temperature of about 33° C., thereby condensing the water and most of the tar. The remaining traces of tar are removed by passing the gas through an extractor. The gas is then reheated by exhaust steam to a temperature of about 70° C., and is passed into a saturator containing sulphuric acid, where all of the ammonia is absorbed. Jn the coolers the ammonia liquor and tar separate by gravity. The am- moniacal liquor thus produced is dis- tilled with steam and lime and the ammonia joining the main gas stream is also recovered in lead-lined satur- ators filled with sulphuric acid, where the salt is precipitated, removed, centrifugalized, dried, bagged, and shipped. It may seem roundabout first to cool ‘ ; 12,000 CUBIC FT. | GAS FUEL 25 LBS. AMMONIUM SULPHATE m | 2.5 GAL.TAR a i 06 GAL TOLUOL '\ Py 025 LIGHT sell 4 4 4] 0.12 GAL. \w alia HEAVY : SOLVENTS 4 ¥ “

ey <

2 LBS. PHENOL possible seven thousand compounds

Valuable products contained in a ton of coal. bination of these products with other substances makes Seven Thousand Products from Coal By 1. Newton Kugelmass

Popular Science Monthly

.

» Se COAL | / TAR AND AMMONIA SEPARATING TANKS AMMONIA LIQUOR TAR r : ; = S | 4 a TAR TO DISTILLING } LANT (, = “ =»: STORAGE TANK

FUEL TO OVEN

Coal is placed in an oven and heated without air.

i ai

ee AMMONIA STILL

x

' \, VAGARHEE)

“hem em aa AGA GA): re)

~«—— ILLUMINATING GAS TO CONSUMER

As a result, the volatile substances in the coal pass off into the system that sepa-° rates one from another and puts them in marketable condition the gas and then reheat it, but this pro- cedure has been found the most desira- ble from every standpoint. First, it is easier to extract the whole tar at a low- er temperature than at a high one. If, in particular, the coal contains much chlorine, ammonium chloride would be produced, and if this were not re- moved from the gas, troubles would ensue, owing to the de- composition of this substance in the _ saturator, causing .a_pro- duction of HCl or hydrochloric- acid gas, de- structive to the lead linings. Be- The com- sides, the gas carries a large quantity of water vapor. On passing through the saturator the gas would give up some of this water and so dilute the bath as to make the formation of solid sulphate difficult. In the present pro- cedure, the gas, instead of depositing water in the saturator, actually carries water from it, thereby aiding the for- mation of the sulphate of ammonia. Recovering the Benzol To recover the benzol, the gas as it comes from the saturators is cooled to 24° C., and then washed with straw oil (petroleum oil of a specific gravity less than 0.875 at 18° C.). After washing, the benzolated oil, containing about 2.5 per cent benzol and its homologues, is run to a light oil still at 135° C. Steam drives off the light oil vapors

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— July, 19%1 COKE OVEN ont i “ee TAR-FLUSHING TANK AMMONIA VAPOR, Lis { EXHAUSTER |] | \ Cd : t L ro € REMOVES FINAL TRACES OF TAR FROM GASES GAS REHEATED Smonrerse rt De FINAL COOLER > | REMOVES FINAL TRACES OF ACID GAS WITH SULPHURIC ACID TO FORM AMMONIUM SULPHATE WATER SEPARATED FROM AMMONIUM SULPHATE FERTILIZER TO BENZOL DISTILLATION PLANT, “3 One valuable product recovered is illuminating gas, which is obtained in large quantities. The entire process can be followed by studying the diagram on these two pages from left to right that pass to a condenser, and the wash oil is returned to be used again. From the condenser light oils pass to a fractionating boiler still, where 90 per cent of the benzol, toluol, etc., is reclaimed. For chemically pure com- pounds a further washing with acid and caustic soda is performed and that product again distilled. Illuminating Gas Produced The gas is tanked in the holder, a constant source of reserve. About 50 per cent is used to reheat the ovens and keep the boilers going; the rest is passed through boosters and sold as impure gas or purified and sold as pure gas. The tar from the separating tank is forced by pumps to the tar-distilling plant. First, it goes through a de- hydration in thin films under partial pressure, and then through a fractional distillation to produce the ten crude components. The stills are horizontal, cylindrical, set in brick with a protect- ing arch under the still bottom. The vapors are condensed in a long worm, arranged as a rectangular coil in an open tank. The condensing water is heated throughout. The condensate is collected in small tanks, where the oils are observed and measured. From. these the fractions are discharged into receiving tanks and thence pumped to storage-houses. The several fractions are light oil or crude naphtha, middle oil or carbolic, heavy oil or creosote, anthracene, and tar or pitch residue. The light oil distillate (from 1to4 per cent of thetar) yields benzol for solvent, dyestuffs, nitrobenzines, sulpho-acids, azo-benzols, explosives, aniline, resor- cin, phenol; pyridin for denaturing; 47 solvent naphtha for xylols; heavy naph- tha for para compounds and varnishes; carbolic acid for phenols and cre~ sols, disinfectants, explosives; toluols for dyestuffs, toluidine, and explosives. A Few of the By-Products The middle oil distillate (from 5 to 15 per cent of the tar) yields carbolic acid for phenols and cresols, synthetic resins, plastics, salicylic acid, dye- stuffs, organic compounds, picric acid, explosives, aspirin, flavorings; neutral oils for paint-thinners and _ stains; lampblack; naphthalin for organic acids, insecticides, naphthols, etc.. The heavy oil distillate (from 14 to 30 per cent of the tar) yields carbolic acid for phenols, cresols, disinfectants; wood preservatives; anthracene for lubrica- tion, organic compounds, dyestuffs, and timber preservatives; lampblack, etc. The residue beyond all the distilled fractions is refined tar and pitch.

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An Electric Stove on a Pedestal . Sonccmeelgie can be found in stoves as well as in other things. There is an electric heater that is mounted on a pedestal in windmill fashion and is so light that it can be carried from place to place. Four elec- tric burners radiate from the top of the pedestal and they are all controlled separately. When you wish to use them, you swing them into horizontal position. The picture above shows one of these stoves with one of its burners in action. If none of the burners is being used, they are turned vertically so that the stove takes up very little room. In the winter- time, the burners can be used for heating. Playing with Lightning § Gen~ is what a discharge of 1,660,000 volts looks like when it breaks down the resistance of an air-gap of 111 inches. There is a deafening roar, a great flash, and the smell of ozone as the terrific discharge crashes across the gap. This spark is only 111 inches long, and represents a voltage of one and one half millions. What voltage must a bolt of lightning represent when it is several miles long? Of course, there is no way of measuring the voltage of lightning, but scientists believe that the pressure reaches many trillions of volts. The picture below was taken at Leland Stanford Junior University, where Professor Harris -J. Ryan is conducting research work along this line. ; Courtesy ‘‘Journal of Electricity” © Keystone View Company A Book that Is as Tall as a Man ROBABLY the largest book ever printed, when the matter of bulk alone is considered, is John James Audubon’s “The Birds of America,’ published be- tween the years 1827 and 1838. But when the size of the page is the only con- sideration, perhaps the largest book in the world is the one shown in the picture above. As you will see at a glance, it is a book of maps. It was put together in the sixteenth century, and contains some forty pages, protected by a stiff cover. Contrast this with the tiny inch-square volume, called ‘‘Brilliants,’” brought out some years ago by Theodore De Vinne. Its pages contained poems set up in ‘“‘Bril- liant’’ type, said to be the smallest in existence. The huge book above is one of the treas- ures in the University of Rostock. Popular Science Monthly They Tried ‘‘Sail-Cars’’ in 1831 wer very long after George Stephenson applied the steam-engine to railroad trans- portation in England, the Balti- more and Ohio Railroad made a unique experiment in which a “‘sail-car” was run on rails. Like a small boat, the car was equipped with a square sail hung from a mast in its center. The flanged wheels were in- tended to hold the car on its course while the wind propelled it down the track. Sails had so long been used as the motive power for ships, that it was not unnatural that inventors should seek to apply them to land transporta- tion. Make Your Own Rope A NEW rope-making machine has re- cently been placed on the market by an Ohio company. With this machine you could weave your own rope out of binder twine. Three strands can be.woven into one, making very strong, tough rope. It is almost impossible to tell where the rope is joined. Several short pieces of rope can be made into one solid piece. The machine also makes rag rugs, sash- cords, shoestrings, automobile tow-lines, rope and wire woven together, and a hun- dred and one other things that cannot be bought in stores. Five pounds of binder twine will make one hundred feet of one-inch rope.

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' ‘ew Aw July, 1921 Much Needed Bedclothes Support for Invalids Grinding-Machine for Reseating Boiler-Tubes os holding bedclothes away from a patient’s injured limb, a ee new boiler-tubes has been made very much easier support has been invented by Laura M. Dobbins, of Orange, New Jersey. The device has wire arches connected by light longitudinal brace-wires. The bars at the base are provided with rings at their four ends to which cords may be secured to hold the device in place. The ends of the cords are secured to the bed-frame. In cases of patients suffering from burns or scalds on the limbs or body, the device is of the greatest practical service. The device is so constructed that it may be folded practically flat, thus permitting of its being carried or stored conveniently. It Tells Time and "THE automatic watchman pictured below never goes to sleep, and is always on the job, ringing a gong and flashing a light when a train or trolley is approaching. When the train reaches a certain point on the track, a circuit is closed and the bell rings and the light flashes. This warns automobiles and wagons of an approaching train. signal is automatically turned off and is ready to sound and flash a warning when the next train approaches. Temperature OOK at this clock and you see not only what time it is, but also how hot or how cold is your room. Often tem- perature is more impor- tant than the time. But why not hang an ordi- nary thermometer be- side the clock? An ordinary thermom- eter will simply tell the temperature. It will not indicate whether the temperature is going up or down; but this little recording thermometer will. vex Its construction is ex- tremely simple and one of the cards over which the needle draws the record of the tempera- ture changes will last a week. Thus you can look over the record and know the past week’s temperature. Send the Clothes to the City Laundry from the Country A LITTLE “house in the country— just the thing for the summer. Make the housework as easy as possible by having bare floors, and using paper napkins and doilies. But clothes and bed-linen must be laundered, and of course the little house is not equipped with stationary tubs, and there isn’t any visible help in the neighborhood. What is to be done? Ship the clothes regularly back to the laundry in the city in suitcases—the kind recently invented for this very purpose. In these cases one side is reversible, carrying a place for the name of the laundry on one side and the name of the customer on the other. This Crossing Signal Acts Like a Watchman TROLLEY CONTACTORS yw _# After the train has passed, the with the use of the little electric grinding-machine shown above. This device quickly removes soot and scale from the caps and nuts of boilers and reduces the time necessary to produce a‘perfectly steam-tight joint. It leaves a highly polished, smooth, accurate surface that may be relied upon. No great skill is necessary in handling the device. A workman of average inte!- ligence may produce a surface that would be envied by a man capable of the very best hand-work attained by years of con- stant practice. Two small wooden handles on each side of the motor enable the workman to hold and guide the little machine. / mde (UNDER SWEAT BAND) —_ | mma Keeping a Felt Hat in Shape OFT felt hats soon lose their shape if they are not equipped with some sort of shape- retainer. Every time you tip your hat or take it off or sit on it accidentally, the felt weakens. Above you see a felt hat into which a metal backbone is being plaged. It was invented by Henry Rust, of Hope- well, Virginia, and con- sists of two steel wires held together at the ends by flat pieces of sheet metal. These wires are very flexible and will fit snugly beneath the two peaks of the hat, keeping it in shape neatly and invisibly and without any inconvenience to its wearer.

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wa 1 boo PRN eee ae eee Ape ens geese ‘ stalled Popular Science Monthly Grind Bones for the Chickens D? you keep chickens? If you do, you will be interested in this bone- grinder, which may be in- in the coop or woodshed. Bones left on dinner-plates are saved, and after they are put Spraying Perfume on the Passers-By OU never know whether you like a thing until you try it. Take perfume, for in- stance. One whiff is enough to let you know whether you like it or not. through this little crusher, they come out in a pulverized condition suitable for the chickens. The grinder is small but sturdy, and as a grinding unit it is indeed powerful, con- sidering its size. The grinder element is turned by a crank, while the bones to be ground are held against the revolving member with the lever shown. After the bones pass through the grinder, they drop into a little pan in the base of the machine. Making Concrete Rough A ROAD-BUILDING engineer, John B. Hittell, thought of the idea of building an asphalt road with a concrete base. It was necessary to roughen the concrete while it was impressionable, so that the asphalt covering would cling to it more tenaciously. A small roller with steel rings attached to its surface was used. Two men, one on each side of the road, drew the roller back and forth across the road with two ropes in the manner illustrated below. Thus the necessity of treading on the soft concrete was avoided. Two and a Half Miles of Rope on This Hoist ig one hundred and forty-five people were placed in a huge bucket, this gigantic hoist would be able to lift the load at a speec of thirty-two hundred feet a minute. It is a husky brute, the largest of its kind in the world. It is driven by a large steam-engine. The rope, which drops into the mine-shaft where the hoist is used, coils itself around the huge drum shown above. The rope capacity of the machine is 13,300 feet— over two miles and one half. With the aid of this hoist the ore from the mine is rushed to the surface as fast as the miners can mine it. Speed is a great consideration in mining to-day, and this hoist will certainly speed up the work in any mine. How Watches Are Cleaned 3 of the large watch factories of the country has a standing order with a bakery: for forty loaves of bread to be delivered each day. What for? To feed its workers? Not at all. quire it. Somebody discovered that fresh bread is the best material for cleaning watches. Reduced to the consistency of dough, the bread easily absorbs oil and takes up minute pieces of foreign matter that might chance to be lurking about. It is the watches that re- 50 A Chicago manufac- turer, realizing this, de- cided to give passers-by the necessary whiff. He inserted an electric fan in his glass show-window, and placed a felt disk, saturated with perfume, behind it. As the blades of the fan revolved they sent the perfume-laden air into the street. Hogs Fed by Railroad ECAUSE a jerkwater railroad company failed, a California rancher bought an eighteen-ton steam locomotive, some small flat cars, and five miles of regulation track. On one of the flat cars he mounted a wooden tank having one thousand gallons capacity, and in it he placed agitating paddles operated by the locomotive. What does he use the tank for? Mixing hog feed. The feed is dumped into the top of the tank from a second-story platform and is mixed thoroughly with water, the revolving paddles reducing it to a sloppy mixture. The railroad track is laid along a central feeding alley on both sides of which are hog-feeding troughs so arranged that each animal is provided with a private dining- table. The front-end of each pen is equipped with a swinging gate that is operated by a trip lever: When the lever is tripped, the gate swings outward at the bottom and rests against the outside wall of the feed-trough. This gives the hog access to the feed. At the side of the tank-car is an extend- able metal feed-pipe that terminates in a four-inch rubber hose. A lever controls the opening or cutting off of the supply. rT. i i a yv F

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July, 1921 The Mirror that Sees Double Bt¥ is a sort of periscopie mirror. With it you can see yourself from two different angles. Women can arrange their hair, men can see whether or not their collars are soiled in the back or they can more carefully examine their recent haircut. When the double mirror is not in use, it can be folded up compactly and placed in pocket or hand- bag. It is light in weight, serviceable, and dur- able. By properly arranging the mirrors, which are provided with swivels, it is possible to see things that could not be seen otherwise. The flat mirror is adapted to reflect a full front view, while the convex mirror is adapted to reflect a reduced full Shifting Belts without Any Danger N ACHINE belts must be shifted from one pulley to another. A perfect alternating action of the upper and lower belt guides essential to shifting belts on cone-shaped pulleys is performed by this belt-shifter. The action is ob- tained without springs or friction-produc- ing mechanism. The complete shifter is supported and alined by the connecting-shaft. Universal brackets permit its application to almost any machine without drilling holes over- head or in the machine. The belt-guides of the device are held firmly sidewise by an automatic gravity lock. He Built a Car in the Kitchen LBERT PELZEL is an automobile mechanic. He decided to build an automobile, but had no workshop; so he used the kitchen. The motor and wheels were bought in a motorcycle shop. The hood was taken from an extinct flivver. The body was made from the roofing of a wrecked freight-car. And the entire car cost less than a hundred dollars. How will Mr. Pelzel get it out, of the kitchen? By taking off the wheels and axles, and lowering the body out of the window. front face of the viewer. PIRAL GR ATE MRR R ~ ws (Re What the Farmers Are Up Against OW to make his life work pay in the face of what the Department of Agri- culture calls “‘hazards of production’— that is the problem that faces every farmer. What are these hazards? Plant and animal diseases, insect pests, predatory animals, rodents. In 1919 field diseases, the Department reports, were responsible for the loss of millions of bushels of oats, corn, potatoes, and wheat. Wheat rust is a powerful enemy of the farmer of the Middle West. Science has found that the fungus responsible for this disease gets its start in the spring in the barberry plant. A campaign has therefore been started throughout the country to eradicate the barberry. If you are an American farmer, you may rest assured that your government is doing everything in its power to make your business a success. If you want advice, write to the Department of. Agri- culture, Washington, D. C. An Unusual Way to Signal the Taxicab IN England a certain hotel em- ploys an unusual method of hailing a taxicab. It might be called a semaphore system. When a cab is not wanted, the signal is down and out of sight. When a cab is desired, the string is pulled from inside and the semaphore goes up. A passing driver.sees it and stops his car. Express companies in this country use a similar system. They provide their patrons with a sign to place in the window. Weeds Killed with Chemicals AILROAD engineers do not like grass or weeds to grow between the tracks. They spend many thousand dollars annu- ally to prevent and destroy the weeds. The chemical weed-destroyer pictured sprays a deadly (deadly to weeds) chemical on the weeds that effectively prevents their growth. This is found to work better than the mechanical weed-pulling devices that have been used by the railroads heretofore. The chemical used is clean, odorless, non-explosive, and harmless to the skin if it is washed off in a reasonable time. 51

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Popular Science Monthly i A cross-sectional view of one of the big turbines. The water rushes into the circular casing, spends its force against the runner, and passes out through the center generator. Mounted on the shaft of the turbine runner is the revolving member of a 37,500-horsepower electric The water drops 210 feet before it rushes into the turbine casing. The three generating units of this installation produce more than 100,000 horsepower Another 100,000 Horsepower from Niagara HINK of astraining line of horses extend- ing from New York to Philadelphia and you will have a good idea of the amount of power fur- nished by one of the big electric generators recently installed in one of the large power plants at Niagara Falls, New York. Each of these spinning giants produces 37,500 horsepower. Water-power is generated by permit- ting a great volume of water to fall from an upper level to a lower level. In this case the upper level is the Upper Niagara river and the lower level is the Lower Niagara river. The difference in height at the point where Produced by three giant generators the water is alowed to drop through the gigantic penstocks or pipes is about 210 feet. A power canal runs around the falls and brings the water to the mouths of the large penstocks at the brink. A solid column of water 1514 feet in diameter rushes down the penstocks at a speed of about three miles a minute. At the end of the great steel pen- stock tons and tons of water spend their force against the blades of a tur- bine wheel. This wheel revolves in a horizontal plane, and connected with 52 the upper end of its shaft is the revolving member of the big electric generator that converts the kinetic energy into electric energy. The water rushing into the penstock is caused to whirl around at a terrific pace. It rushes out at the center and passes into the river. A huge valve is located at the bottom of the penstock, and the water passes this just before it rushes into the turbine. This valve is hydraulically operated and electrically controlled. The big valve, weighing several tons, is moved forward merely by closing a switch, when it cuts off the flow of water in the penstock.

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— 7 ee _ Q wee Co FN i a eS OBS SS @ ct July, 1921 The lookout presses a button, which immediately releases the life-buoy The Life-Buoy that Flares in the Water * AN overboard!” Hearing the cry, the lookout presses a but- ton. Several life-buoys drop to the water. As they strike, torches flare. These buoys are of copper; fastened to opposite sides are metal rods that have at one end perforated compart- ments containing calcium carbide. The rods turn on pivots. As the cal- cium carbide comes into contact with the salt water, the acetylene gas gener- ated bursts into flames, which usually lasts until the buoys are picked up. © Kadel & Herbert Metal rods on this life-buoy become torches when the buoy hits the water Trolleys ROLLEY-TRACKS are very much in the way. Hence the trackless trolley- car is now coming into use. The car gets its power from an overhead wire by means of the usual trolley-pole. The motorman must steer the car, as well as control the power and brakes. His job is harder than that of an automobile driver, for he must make his ear follow the straight and narrow path under the wire—if not, the pole will break away. Strangely, one of the first of these advanced trolley-cars appeared in Tokio, where the jinrikisha is still in vogue. The car itself is not unlike our American trolley-cars; it has, however, a large wire fender in front to catch Can a trolley-car do without tracks? This picture answers the question. In the motorman’s box is a_ steering- wheel that keeps the car in place be- neath the wire 53 All the Thrills without the Danger F you have felt the high cost of airplane rides to be a serious bar to pleasure, here is the airplane railway for you. You board this lifelike-looking airplane comfortably from a platform reached by a that Have No Tracks stairway. The airplane swings out into the air in a most realistic manner —if you do not notice the track. The track, however, is important. It is a monorail that firmly supports the airplane anybody who fails to get out of the way. In Bradford, England, an- other trackless trolley-line is in operation. The cars look like two-story buses, and have the usual hard rubber tires. The current passes through an electric motor, which drives the rear axle through sprocket wheels and chains. How, then, is the current from the trolley-pole grounded? By means of a second trolley-pole, which carries the current back to a second wire, on to the power house. When tracks are used, they carry off the current. One advantage of the trackless sys- tem is that it eliminates blocking.

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oo pears 2 eta es te RE EI Pate 1 5 ED nar ete nA RI mem Sn Popular Science Monthly Helping the Aviator to Find Himself With the assistance of the chronometer and sound waves By P. J. Risdon English correspondent of the Popular Science Monthly NE of the principal difficulties that confront an aviator is that of ascertaining his position and altitude when flying through or above clouds or in foggy weather. Another is to locate a flying-field and to land there in a fog. Since, in employing aircraft for business and mail-carrying, flying must go on in all weathers, means must be found in cloud or fog, and that his altitude is 1100 feet. His altimeter may register a height of 3000 feet from his base station, so that, without knowing it, he has reached hilly country. He now fires a detonator, and (ignoring for the moment the difference between the speed of sound in cloud and in clear varying in length according to their distance. The detonations at different stations may vary in quality or in- tensity, to lessen the risk of confusion. The upper left-hand figure on the opposite page indicates the position of an airplane ascertained in this manner. A, B, and C are three stations, and the black dot indicates the position of the airplane. for doing so in safety. The great advances made in the adaptation of wireless telegraphy and telephony to aircraft have temporarily over- shadowed the possibilities of sound-ranging, but Professor G. H. Bryan has recently re- vived the subject. His report merely outlines his scheme of applying sound so that an aviator will know his position and altitude at any moment. The scheme comprises two elements. By means of the first, an aviator following a recognized air route would be directed by sound signals re- ceived from base _ stations established along the route, the correct interpretation of which would enable him to take his bearings every minute and thus know within a rea- sonable margin the course he is pursuing. The second element is based upon the time taken for the This shows the method of cali- brating the dial of the aviator’s chronometer. chart. The text will tell you how this helps the aviator to find himself in a fog or rainstorm when he cannot see the ground If it were on the ground, the three curves of the 4-, 5-, and 6-mile radii would all inter- sect at one point, which would be its position. But since it is not on the ground but in the air, the sound waves rise, forming, as it were, an imagin- ary irregular pyramid with a triangular base. By drawing lines from the intersections of the curves perpendicularly to - lines joining the stations, it will be found that they inter- sect at the position of the air- plane. Itisthen merely a matter of trigonometrical calculation. Enter the Chronometer But Professor Bryan does not expect an airman to per- form trigonometrical feats. He proposes a simple device by means of which the second- hand of the pilot’s chronometer will indicate his position in re- gard to the three base stations. sound of an explosion, caused by the pilot on or just beneath the machine, to reach the earth and rebound to a receiving instrument on the airplane. At the present time an airman has no means of ascertaining his height. His altimeter records only his height above sea-level, and is set according to his base station. Conse- quently, unable to see around or below him, he may at. any moment foul rising ground or buildings. Detonations produced by the pilot himself would render him independent of ground signals. Can Sound Be Depended Upon? Expert opinion is divided as to the practicability of effectually guiding aircraft by sound. Only experiment can determine to what extent accuracy would be impaired—for instance, by banks of cloud of varying depth and density and with gaps or “holes’” in them. Let us suppose that a pilot is flying air) the sound will take two seconds to reach. the earth, rebound, and be de- tected by. his microphone. Assuming the speed of-sound to be 1100 feet a second, he will thus know his altitude. By firing a succession’ of detonators he will keep himself ac- quainted with it, and fly accordingly. At present sound signals from the airplane are picked up by receiving stations, from which guiding wireless messages are then despatched and received by the airman: Professor Bryan proposes to make the airman independent of wireless. He there- fore proposes that along every air route there should be established stations that will emit sound signals at inter- vals of one minute. The stations will be spaced several miles apart, and arranged triangularly, that is to say, so that straight lines joining any three of them will form a triangle. As the airman proceeds, he receives these sound signals at intervals of time, 54 All the chronometers at. base stations and on the airplanes wouid be set to standard time. Around the second-dial of each pilot’s chro- nometer would be circles graduated in miles. The distances apart of the cir- cumferences represent heights in feet, the graduations round the innermost circle represent horizontal distances at ground level, and the graduations of the other circles represent horizontal distances at various levels up to, say, 33,000 feet. Now, all the stations would send out their sound signals at an exact minute, and according to his distance from each station the sound would take more or less time to reach a pilot. If by his altimeter or by the method already described-he had ascertained his alti- tude to be 2200 feet and then heard a sound signal just as the second-hand of his chronometer pointed to two seconds past the exact minute, he would know that he was over the station, because the sound would take two seconds to reach him. vy , ny . a >. a -

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July, 1921 4-MILE RADIUS spay es: GER Es ee em “ es a - othe { ee SECTION. HOW AN: AIRPLANE MAY FIND ITS ALTITUDE BY TAKING SOUNDINGS WHEN THE. “TSPUprer SURFACE OF CLOUDS ta 3S a ee ti - mg 2 kek © Modern Publishing Co. ——— = Drawing by G. H. Davis Guiding Airplanes by Explosions Recorded on a Chart This system of locating an airplane is based upon the time taken for the sound of an explosion, set off by the pilot of the airplane, to reach the earth and rebound to the airplane. The altimeter now used merely indicates the height of the machine above sea-level. The airman can locate himself by receiving sound waves set up by three sound-producing stations Tt. S0aa7 55 arranged in a triangle. These stations would be placed several miles apart and they would emit signals at in- tervals of one minute. As the airman proceeded he would receive this sound signal at intervals, varying according to its distance. By watching the chart of his chronometer, the air- man can determine his exact position

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sae a Sp ma ee ee anes SE a Popular Science Monthly & The Government’s Method of Testing Tires N° mercy is shown when automobile tires are tested at the Bureau of Standards. Tires are purposely run until they are fit for nothing but the scrap-heap, but the data that such tests make available are worth many times the price of the tires used up in the tests. The tire-testing machine shown above was désigned especially to measure the power loss and energy dissipated by heat generated in the tire through friction and slippage? With this arrangement, the pressure of the tire against the wheel with which it is in contact may be measured. Live Wires Covered by Blanket pnt mid ltren have recently turned their attention to the protection of electrical workers, and many devices that reduce the hazards have found their way into the market. Below is an insulating blanket to be used to cover ‘‘hot’’ wires and prevent accidental contact when a workman is making repairs on wires adjacent to the live wires. It is simply placed over the live wires and clipped together at the bottom with two pins to prevent it from falling to the ground. Bed 9 se = Cd oo a — It Folds Like an Umbrella A= makes grown folk sleepy, so it is not surprising that babies want to go to sleep soon after they reach the beach. But how can you protect a baby at the seashore from flies, ants, and other insects? Above is shown a new collapsible canopy that will fold up and fit in a narrow case just as if it were an umbrella. When ex- tended, it is large enough to accommodate a child. The net that entirely covers the frame will keep out all flies and bugs. Such a cover as this will relieve parents cf much worry when taking the baby to a picnic or to the seashore. How Small Is a Hummingbird? [ase two young ruby-throated hum- ming birds represent the smallest species of feathered life inhabiting eastern North America. They were found one June day in a sugar-maple tree in Penn- sylvania. The discoverer, standing by almost without breathing, saw the mother bird bring her babies food, thrust her long beak down the throats of each youngster and empty her beak of the nectarous juices that she had carried from a flower-garden. The young birds were photographed near a fifty-cent coin to show their size. Strangely enough, when the picture was being taken, the little birds thrust out their slender tongues in rapid succession. 56 © Boston Photo News Co. Breaking Up the Cream in Milk “QHAKE well before using.” That holds good for milk as well as for medicine. If milk stands an hour or so, all the fatty, creamy part rises to the top, leaving the watery part below. Now, however, there is a machine that will break up the cream globules so thor- oughly that they can never combine again. Thus the richness will be distributed throughout the milk. There are four agate needle valves on the machine through which the milk is forced at high speed. As it rushes through a valve the fat is broken up. — Tickets Printed While You Wait E know the world moves fast. So do ticket-sellers of some European rail- roads. They print your ticket while you wait. You tell the man your destination, and he disappears for a few minutes and re- turns with your ticket, having printed it in the meantime. He hands it to you while the ink is still fresh. With railroad rates and schedules chang- ing as they do nowadays, this ticket- printing machine has filled a much-felt want. There is no wastage, since every ticket is printed to correspond with the conditions to be met at the time it is printed. ; ewe poe Gs ey , gee 2 a

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—. = -—-. = July, 1921 The Air-Driven Pick Is Easy to Use S the old ‘“hand-driven” pick doomed? Here is a modern pick working as mod- ern things should work—by compressed air. This old man has thrown his hand-pick away. His air-driven pick is especially efficient at tearing up old asphalt pavements, and it is seen at work in the picture. With it a man can dig up a square yard of pavement in three minutes. Only a small fraction of this amount could be dug up with an ordinary pick. In fact, it often re- quires this time to dislodge a . single piece. Any _ ob- servant per- son must be Putting Tools Where They Are Needed NY automobile driver will testify that garage me- chanics spend most of their time going back to the store- room -to get the tools they need. To obviate this, a truck has been devised by a Los Angeles garage-owner that is equipped with every tool that could possibly be needed in electrical “trouble-shoot- ing” and repair work. This is really a complete store-room in itself, being arranged with drawers for supplies and tools and other necessary apparatus. It is mounted on wheels and is easily moved to aware that compressed air is making rapid strides in industry. It would be difficult to estimate, however, the amount of labor-saving it has accomplished. France’s Population Normal in Seventy Years? pRAnce lost several million men during the war. Professor O Richard Strong, of Harvard, claims that it will take France Leggings to Protect the Foundry Workmen from Burns JORKMEN in foundries are con- stantly handling molten metal, and precautions should be taken against the serious burns that frequently occur. A drop of metal will penetrate clothing and scorch the flesh. Leggings made of asbes- tosized duck have been found very effective in preventing-injury. The material is highly glazed and the molten metal will not cling to it. The leggings worn by the men in the picture above are constructed around spring-steel frames; there is an inside and an outside covering. The leggings snap on. the car to be repaired. The mechanic has any tool he wants right at hand. The picture below shows this useful truck. Chickens Singed with Acetylene NE of the most recent uses for acetylene is for singeing chickens. It is said that the acetylene flame, properly used, seventy years to bring her population back to normal. Which performs this operation in a small fraction of the time usually means that in the year 1991 France will have a population that will compare favoravly with the population she had before August, 1914. A reduction in population means a reduction in income. It would be interesting to know how much the war cost France with this item included in the actual expense. required, that it removes the last vestige of feathers from the fowl, and that the burning off is accomplished without scorching the skin or heating the delicate flesh. This is no more remarkable than the use of acetylene in remov- ing paint from canvas, which is done without even the slightest injury to the fabric. He Carries His Own Telephone Wires INES of communication are established in the vast wooded tracts of forest preserves by means of fine wire carried on portable reels. Lightness is of prime importance, for the lines must sometimes extend consider- able distances, especially when a fire is being fought; the progress of fire-fighters must not be hin- dered by any lack of communi- cation. In order to make means of communication more certain, the United States Forest Service makes use of small reels such as the one shown in the illustration. The forester can carry it without impeding his progress, and he unwinds or winds up the wire as he follows the trail, looking out for indications of fire. Folding Screen Chair for the Garden REEN trees, blue sky, golden sunlight—for all these it is easy to give thanks; but cater- pillar, ant, and mosquito have a habit.of distracting one’s thoughts from higher things and dictating a swift retreat to the screened porch. Which is one reason why Stephen Stransky, of Darby, Pennsylvania, invented his screened chair. It is a very com- fortable chair, for besides being screened, it has arm-rests, a book- rest, and rockers. As if this were not enough, the chair, rockers and all, can be folded up into a com- pass not much larger than an ordinary door. The hinges are of the removable pin type, so there is little diffi- 7, Arf @ 57 culty in unfastening the parts.

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Popular Science Monthly Protect the Ice-Cream Cone CE-CREAM in the cone is good eating, the cone as well as the cream; but many people throw the cone away because they know it has been handled. Now, however, there is a cone-holder that protects the cone both from too much handling and from dust. This protector is an oblong case made of metal and glass, and it holds fifty cones. Three sides of the case-are of glass; the fourth and the cover are of metal, hinged together. When there are no customers present, of course the case is closed. But while business is going on, the metal cover and one side are opened as shown in the picture above. There is a narrow perforated shelf at- tached to the front of the case in which filled cones are placed ready to be eaten. In this manner, the danger of disease from germs is considerably lessened. How Sandbags Save the Lives of Aviators Repel airplanes by the sandbag method is a very severe method, to be sure. In fact, it is testing them to death. Hundreds of little sandbags are placed on the wings until they crash under the load. At this time the aeronautical engineer may find just where the first sign of weakness manifested itself. Then he gets out his slide rule and mathematical tables, and figures out a remedy. Oftentimes it is merely a matter of ten- sile strength, or it may be a matter of faulty design. In any event, the sand- bag weight test brings out the point of weakness, wherever it may be. Of course, this method of testing is not applied to every new machine. It is used only when the first machine of a new class has been made. Moving a Large Camera Piano Fashion O large was a color-process camera bought recently by a Washington, D. C., engraving plant that it would not fit in the elevator of the building. Four men, operating a block and tackle, raised the camera to the roof and lowered it through the skylight to the fifth floor, where the company has its operating-room. The camera takes a picture thirty inches square, the bellows are more than ten feet long. The camera is equipped with a special stabilizer frame to obviate risk of damage to the immense plates by reason of vibration during exposure. The camera will be assigned to do color jobs for the federal government, and is already engaged in producing the colored designs of the official publication of the United States Chamber of Commerce. The lenses of the apparatus are complete, with filters for blocking out colors on two,- three-, or four-color half-tone assignments, permitting accurate reproduction of oil and water-color paintings. - The machine, including accessories, cost approximately three thousand dollars. The brilliant illumination that is focused on the object being reproduced has twice the strength of the light available for a camera twenty by twenty inches in size. Beauty at Any Cost Mest of the apparatus of a beauty parlor looks like instruments of tor- ture, at least to the unaccustomed eyes of a man. It is safe to say that some of the results obtained have been at the cost of physical discomfort. The device pictured above admits steam to the lady’s face, which is enclosed in a “steam-box.”” The moisture at a comfort- ably hot temperature expands the skin and improves the circulation of the blood. The result of the treatment is said to be a marked improvement in the complexion. An indicator outside the box shows the temperature within, and the steam is ad- mitted gradually until the right degree is reached. All Conveniences on This Life-Raft IFE-RAFTS for ocean-going vessels are as numerous in design as are the designs of non-refillable bottles and rail joints. Below is still another, however, that appears to ‘‘fill the bill.’’ This raft is a square wooden framework, and at each corner is a water-tight tank fitted with a patent air-shaft for the accom- modation of passengers. Between the tanks are chambers for the storage of food, clothing, heating appliances, a sail, and wireless telegraph apparatus. The raft is placed upon the deck of the vessel, and in the event of a shipwreck it is simply rolled off into the sea. The picture shows the inventor trying a model of his raft on the Thames river at London, Eng- land. White mice were used in the experi- ment,

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ity or- | of the of am n a yrt- and » be on. the ad- e is ssels the rail ver, ork, rank -om- the ood, and the ‘it is ‘ture f his Eng- peri- July, 1921 A Megaphone-Fan for the Baseball Fan i dees swing at it like a gate!’ shouted the exasperated fan through a small cardboard mega- phone. He was hot under the collar, so then he opened up the megaphone, slipped it in a wooden frame, and fanned himself with it. The batter, in the meantime, grew peeved, swung at the ball, and scored a run. Whereupon the fan who was fanning himself recorded the run on the back of the fan. Do you get it? This combination megaphone, fan, and score-card was invented by George K. Asano, of Dalhart, Texas. Make Your Bed in the Car RICES charged by hotels have caused many an automobilist to make his own bed. But when you are touring all day you really should have a comfortable bed at night. There is now a regular spring-bed that can be erected in a few minutes inside of the car itself. One end of the bed-spring is clamped to the back of the car. The other end is attached to the wind-shield by means of iron triangles. There is practically no strain on the wind-shield, for ropes extend from the opposite angles of the triangles to the front mud-guards. The pull in each direction is the same. Efficiency in Hay-Wagons WO men, after driving this hay-truck from the farm or railroad-station, can, unaided, deposit their bales in a loft. The structure of the truck is shown clearly in the illustration. While the chassis is of the regulation type, the body is a hay-carrying model. The part that is - unusual about the motor-truck is its lifting apparatus, which, with the action of two powerful arms, will lift the body and its contents six feet above the chassis. When the wagon is empty, the arms slowly fold and the truck resumes the ap- pearance of an ordinary truck. With such equipment labor is not such a serious matter with the farmer of to-day. Mining for Gum es for gum is a great industry in the North Island of New Zealand. It is not chewing-gum, however, but a resin varnish gum that is the residue from pre- historic forests. This fossilized resin is only a few feet below the earth’s surface, and the ‘‘miners”’ dig it out with pick and shovel. This is a sort of free-lance occupation, and many men have made small fortunes in this digging. The gum has many uses, the principal of which is in the manufacture of varnish. —. Bene “ena; i ~f- Electric Lights from the Water System HEN the faucet is turned on, water flows through the pipes. If the moving water is allowed to pass through a small water-motor or turbine, a certain amount of power will be generated without lowering the water pressure undesirably. A French scientist named Colar- deau has invented a system for generating electric current, and feeds it to a storage battery every time the water in the house is turned on. The current in the battery accumulates from day to day, and may be used to light several small lamps. Of course, this method supplies only a small amount of current. Air- or Steam-Driven Tugger | be industry there are a hundred and one uses for the little machine shown below. It is a jack-of-all-trades when it comes to tugging and lifting. It may be used in place of a hoist or a horse, since it will both pull and lift. Here it is shown lifting a wheelbarrow of bricks up to the fifth story of a building under construction. It is fed with com-, pressed air, although steam may also be used. There is nothing to do but pull over the throttle. The machine is small and so powerful is it that it is used to move loaded freight-cars when the switch-engine is not available. oa 10907

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ee ee eo Bat i ee Ls APSA as eres Ki ns 2 ee ET tT aT I I A > 5 aha _/ =z 5 FUNNEL FOR RECLAIM THE BULLETS WASHED DOWN One man moves a hose across the ends of the condenser tubes. Compressed air shoots the rubber plugs through Tubes Cleaned with Bullets OW much time would it take one man to clean out nine thousand long metal boiler tubes? It would be such a task that the power plants where surface condenser tubes had to be cleaned formerly put six or RUBBER YY BULLET ) / eight men at work on the job, and even then it took a long time, for the men had to do the work by hand. Generally they used rods, running them in and out of the tubes until they were clean. Steam turbines need these condensers to produce the py exhausted. vacuum, the smaller the steam consumption and the greater the amount of fuel saved. Clean tubes insure high heat transmission and con- sequently a maximum vacuum. Thou- sands of gallons of water are pumped through the cooling tubes of the con- denser, and small particles of debris finally coat the inside of the tubes. This coating acts as an insulator, and must be removed. One workman can now clean the condenser with rubber plugs equal in “number to about 25 per cent of the number of tubes. He places one plug in the end of each tube. Then he takes a hose that has a quick-acting é CONDENSER wire brushes attached to long re How the rubber ‘“‘bul- lets’”’ are forced through the metal boiler-tube ‘ compressed air; vacuum into which the steam is_ water also can be used The higher the for propulsion ceivers NOZZLE = ae The microphone and _ bat- teries are carried in a leather case. This is called the ‘“‘Tom Thumb” of telephone re- er, a consideration to Popular Science Monthly cin) Lhe Telephone for the Deaf LECTRICITY has aided deaf people before this time, but this time it comes in the form of a tele- phone receiver so diminutive that it fits into the ear. It is the “‘Tom Thumb” of telephone receivers. Its size, although it might tend to reflect on its efficiency, does not affect it in the least. It reproduces speech perfectly. The diaphragm of the little receiver vibrates very close to the ear-drum, and a person would have to be extremely deaf not to hear it. A very sensitive mi- crophone and _ batteries are used in connection with the tiny receiver. These may be carried about in a small leather case. The microphone is a sensitive telephone _ transmitter. It picks up the sound waves and transmits them to the receiver, which is located against the deaf per- son’s ear. © ; The entire equipment is light in weight and serviceable and efficient in action. Also it is not unsightly as to cause em- barrassment to the wear- business men and women. Six Thousand Trees in a Bale HE United States government, as guardian of 174,261,393 acres of national forests, is replenishing de- nuded woodlands at a rate of seven thousand acres annually. Seedlings are nurtured in screened beds, 150 trees to the square foot, with as much jealous interest as is evidenced by the professional nurseryman whose busi- ness is fruit-tree propagation. The government nurseries are maintained in the forests of valve, and moves the nozzle across the openings containing the rubber “‘bullets.’”’ Either compressed air or water serves to shoot the bullets through the tubes under a pressure of eighty pounds. A bucket placed under the drain-pipe at the bottom of the condenser catches the plugs. Each plug can be used 250 times or oftener. Special plugs containing an abrasive mixture in the rubber can be used in cases where a hard scale is en- countered. By the new method a vacuum two tenths higher can be obtained than with the hand method of cleaning, and a saving of more than 75 per cent in the cost of the work results. As guardian of its national forests, the United States government annually ships millions of seedling plants to denuded woodlands. trees aré compressed in this baler, which allows of sending six thousand pine-trees in a single unit 60 Young the West, from which the seedlings are distributed throughout the United States for reforestation of @ supervised area equal in dimensions to four states the size of Iowa. The largest of these tree-yielding beds, the Savenac nursery in the Lolo national forest of Montana, can pro- duce three million plants a year. The oh, young trees are baled o and shipped to widely separated parts of the country. The govern- ment baler, — here shown, has a capacity for compressing within single units for ship- ment, six thousand Western white pines. Community Ice Y running its own plant, Lindsay, California, cut its ice-bill in half. The Chamber of Commerce bought a local plant, sold stock to three hundred _ citizens, and the secretary of the Chamber took charge. In its first season the plant manufactured one thousand tons of ice, at a saving of thousands of dollars.

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ly his le- It ze, 10t “he tle ery im, ave not mi- ries ion ver. ried cher one one sup. and the ated per- nent and ‘ient ; not jear- 1 to men. s are nited vised tates lding Lolo pro- The baled ‘idely yf the vern- here acity rithin ship- sand pines. \ue plant, ut its ber of plant, ndred ry of plant dtons sands July, 1921 How an Under-Water Steam-Whistle Is Produced HEN you talk, you cause the air between your mouth and the ear of your hearer to pulsate. Like air, water can be made to pulsate. If you strike a bell on the water, the sound will travel much farther than in air. Hence, many ships. are equipped with bells, which are sounded under water and which are much more efficient than fog-horns. Two English scientists, Mr. Gerald Stoney and Mr. Tel- ford Petrie, conceived the idea that it might be possible to produce sounds under water by steam. After many dis- heartening experiments, they succeeded in devising a very efficient under-water steam- whistle which is an extremely case of the Stoney-Petrie steam-whistle the sound can be heard four miles away. The steam-whistle consists simply of a steel disk having a hole in the center for the pas- sage of a steam-jet, and sup- ported on opposed knife-edges at two points on a circle. The steam spreads out like a mush- room as it strikes the flat sur- face, the hotter central core escaping through the hole. The mushroom travels back away from the flat surface in the form of a ring or disk of bub- bles. The ring collapses, but the onward rush of steam forms another mushroom as the previous one disappears. This happens with - great rapidity. Thus a musical note convenient and cheap appara- tus for producing loud, pene- trating under-water tones, Of course, these under-water tones, whether they are created by a bell or a steam- whistle, cannot be _ heard merely by putting the ear close to the water. An in- strument called a hydrophone picks up the sounds. In the Clearing Stony Land | In the first under-water steam-whistle a_ steel disk, with a hole in the center, is supported on opposed knife-edges at two points only. Part of the steam shot against the disk from a nozzle passes through the hole; the rest mushrooms and then collapses. The al- ternate rising and falling of the mushroom pro- duces a penetrating note (a) Steam mushroomed by disk. Hot central core -passes through hole; (6b) Mushroom travels ‘back from disk in form of a ring of con- densing bubbles; (c) Ring collapses on and around the nozzle; (d) On- ward rush of steam forms mushroom is produced by a series of pulses or blows of steam. It is not the vibration of the steel disk that produces the sound, but the rapid action of the con- densing steam. This amounts to ringing water on water, just as we would ring iron on iron. Stereopticon Changes Pictures Automatically by Machinery A useful apparatus that will clear land of stones without any back- breaking hand work VERY farmer who has a rocky pasture will be glad to know that there is now a stone-gathering rake that can be hitched to a team of horses and do the work almost automatically. This invention of a Bohemian engineer is made up of several rotat- ing rakes, which bite into the soil to a good depth, lifting up any stones in the earth and depositing them in a receptacle extending across the back of the apparatus. The oper- ator merely drives the horses. Taslas 1007 HE stereopticon has been modern- ized in the form of an automatic machine that takes the projected pic- ture out of the dark-room and permits This automatic stereopticon is designed for commercial display principally; the slide is first thrown on a mirror, from which it is reflected on the front screen 61 its use for displays in show-rooms or windows. The perfected machine shows any number of lantern-slides up to fifty in continuous rotation in the daylight or night. The pictures change every seven to thirty seconds either automatically or by the pres- sure of a button. The machine is made with two sizes of screens, respectively sixteen by fifteen inches and twenty inches square, and may be operated from an ordinary lighting circuit at a cost of four cents an hour. The machine has retained its boxlike form, with closed sides, back, and top and bottom, with a screen in front at the top. The development has taken place in the mechanism inside for automatically picking up each slide in turn and elevating it so that its image may be thrown on a mirror at the back of the box and then reflected to the front screen seen by the observer. The slides are held in order on a slanting framework and picked by a hinged mechanical finger device. One thirtieth horsepower operates the slide- selecting finger apparatus and a condensing system for day- light projection.

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at aN Peddlers from Petrograd to Cairo | Anything, even alligators and stoves, sold in the street Popular Science Monthly His monstrous key-ring and mysterious tools On his head this peddler of Naples carries stoves, pots, They are held to- gether by cords, and must be separated when one of their company is sold and pans. On hot days in the streets of Florence you will see Italian women peddling The fans are not like our fans, but are circular in shape, varying in size fre “as era: SASS MF EIS pronounce him an hon- est Polish locksmith In Spain there is a great demand for turkeys. Here is a merchant and his mule with a load of live turkeys In spite of unsettled conditions in Ti Warsaw, people are still buying i sponges, presumably to wash with. j Here is a man who sells nothing but ; sponges and makes a fair living at it Balancing a stuffed alligator on his head and carrying a turtle, this hopeful peddler roams the streets of Cairo. He sells other things—chiefly beads 62 Evidently canes are fashionable in Constantinople, judging from the picture above, where all sorts of canes are shown; also the Turkish peddler sticks to his fez

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July, 1921 From tiny pieces of gutta-percha they grow to the finished sphere Golf-Balls and How They Are Made India-rubber thread -is wound around the taped ball with the help of a small winding-machine. The oan — rollers revolve, carrying the ball This is the first event with them, while the operator of a golf-ball’s life: guides the rubber thread rubber tape is wound around a piece of gutta-percha. The winding is done by hand. In the wind- ing the embryo ball becomes round The rubber ball is fitted into one of the gutta-percha shells and then placed in a heated mold. It is capped with a second shell and ‘the other half of the mold; _ it comes out a ball A coat of paint is the last thing that a golf-ball re- ceives before going into Service. The painting is done by hand, and care must be taken that it is put on evenly. If not, the ball will follow a swerving course when it is played The gutta-percha shells into which a rubber ball is fitted are stamped out in this machine. When heated to the tem- perature of boiling water, . gutta-percha becomes soft and im- pressionable The mold _ that unites the various parts of a golf-bail has small hemi- spherical protuber- ances on its inner surface.. Thus, when the ball is re- moved, it is covered with depressions

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SEER MME ENE SF SST FE NCAT RIOT OS TNE MEE a er eens FETE SS TR SR SF TREO PRP OT A 5. = SE ne eae P oo sun Betelgeuse is By about 354,000,000,000,- 000,000 miles distant from the earth. A distance of one two hundred millionth of an inch has just been measured. Our imagination is help- less when faced with such tremendous figures. In the one case, man’s unit of measurement, the inch, is hopelessly large; in the other case its smallness makes it utterly insignificant. A millionth is the thousandth part of the thousandth part. A millionth of a mile would be less than one seven- hundredth of C. A. Briggs and Raymond F. Yates that one current superimposes itself upon the other current. But what effect does this have on the frequency of the current in the second circuit? We must not think that the frequency of the first current would be added to the frequency of the second current. Instead, we get what might be called a “beat note” in the circuit. This beat note will have a frequency that will be equivalent to the difference in the fre- Popular Science Monthly Measuring One Five Hundred Millionth of an Inch There is a machine that does this with perfect accuracy When the condenser becomes “charged” (full), it discharges. The capacity of a condenser de- pends largely upon the size of the metal plates and the distance between them. The larger a condenser, the longer it takes to become charged and discharged. Therefore it affects the frequency of the circuit of which it forms a part. Now, the circuit we are considering is extremely sen- sitive to a change in capacity, and if the plates of the condenser are moved a distance as small as one two hundred an inch! With these staggering figures in mind, let us set out to see how a five hundred millionth of an inch is measured with perfect accuracy. We must first under- stand what is meant by an alternating electric eurrent. The current that lights our homes may have a “frequency” of 25, 60, or 133 “‘cycles.”’ This simply means that the current travels first in one direction and then in the opposite direction 25, 60, or 133 times would scientist. How a Fly Bends a Half-Inch Steel Rod MAGINE a steel rod one half inch in diameter and twelve inches long. held horizontally with one of its ends in a vise and a fly on the opposite end. Would you believe that the weight of the fly It does, and with the electrical measuring system here de- scribed it is possible to record the distance! This work in ‘‘ultrameasurement’’ has been done by Prof. R. Whiddington, an English With this system a distance as small as one five hundred millionth of an inch may be measured. bend the big steel rod? Imagine this rod millionth of an_ inch, there will be a noticeable change in the frequency of the beat note. We see, then, that our measuring device is really an_ electrostatic condenser. The Condenser in Action The plates are in a frame, and one plate is provided with a meas- uring-tip. Pressure on this tip changes the dis- tance between the plates, and this in turn changes the frequency of the (cycles) a second. Such currents are called low- frequency currents. By the use of special apparatus, electric currents of small strength have been made to alternate ten million times a second. Alternating currents of high fre- quency may be generated by that wonderful little Aladdin’s lamp called the vacuum tube. It is unnecessary to explain its operation. We shall simply keep in mind the fact that with the aid of vacuum tubes we obtain electric currents of very high frequency. What Is Electric Induction? Let us imagine two electric circuits, each containing a vacuum tube. The vacuum tube in one circuit will be pro- ducing a current with a frequency of 100,000 cycles a second, while the tube in the other circuit will be creat- ing a current with a frequency of 101,000 cycles a second. Now, when two electric circuits are brought to- gether, the current in one has a ten- dency to “induce” itself in the other circuit. This is the phenomenon of “electric induction,” and in our case the 100,000-cycle current-in-one.circuit will induce itself in the circuit with the 101,000-cycle current. What happens then? We shall see quencies of the two currents. It will have a frequency equal to the differ- ence between 100,000 and 101,000 cycles, or one thousand cycles. The frequency of any electric current - depends upon the values of inductance, capacity, and resistance of the circuit in which it is flowing. Any changes, even the slightest, in these values will change the frequency of the electric current. Thus, if we in- crease the resistance (the opposition to current flow) of a circuit, the fre- quency of the current will be lowered. If we change the capacity, the fre- quency also changes. Now we are going to center our attention on capacity, since it is through a change in the capacity of the electric circuit before mentioned that the measure- ment of small distances is made pos- sible. First, what is electrical capacity? All we need to know is that a large part of the capacity of the circuit we are interested in is represented by two metal plates separated from each other by a non-conducting medium (in this case, air). Such an arrangement con- stitutes an electrostatic condenser, and an electrostatic condenser has a certain “capacity” to store electric energy. 64 circuit in direct propor- tion. The. change in frequency is recorded in numbers on a frequency meter, and from this is computed the distance measured. The tremendous sensitivity of this device brings us into a new world. When a penny is laid on a table-top, this device is able to measure the bend in the wood due to the weight of the coin! A piece of steel is like a quiver- ing mass of jelly. We can watch it ex- pand from the heat of the body of a fly walking on it. Such a measuring system could never be applied in a practical way. However, the sensi- tivity can be regulated, and before long we may have a practical measur- ing system that will be accurate to a five hundred thousandth of an inch— which is plenty! The present arrangement is so sen- sitive that work has to be carried on at night to prevent interference from the city traffic. The measuring condenser may also be employed as a very sensi- tive indicator of sound. The sound waves of the air impinging against the movable condenser plate will cause disturbances in the circuit and if a receiver is used in place of the fre- quency meter, sounds of very small magnitudes can be detected over tre- mendous distances.

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sic his ‘Id. op, ond the rer- ex- fa ‘ing na nsi- fore 3ur- oa “a 3en- n at the nser nsi- und the ause if a fre- mall tre- July, 1921 FREQUENCY METER + variaatee | % R CONDENSER ‘H_OBAITERY _ MILLI-AMMETER ne “a AMMETER., 2 RHEOSTAT 00 TO | LEVER SYSTEM Wh MICROMETER” INSULATE £ NUT SEGMENTS (iN METAL pe AT} >} i MEASURING CONDENSER FIRST CAR _ Measuring a-Millionth of an Above is a practical electrical measuring device for shop use that is sensitive to one one millionth of an inch. It is so designed that it can be manipulated by a workman without any knowledge of electrical or physical laws. A lever system with a ratio of 100 to 1 is used in Inch in the Machine-Shop connection with the measuring condenser, which is shown mounted at the end of the steel bed. A de- pression of the plates in the measuring condenser causes a change in the frequency of the circuit, which is indicated by the frequency meter on the top Here is the circuit in which the ‘‘beat notes” are produced and am- beat note, is included in this circuit. The change in the fre- quency of this note is caused by the varia- tion in the distance between the plates of the condenser’ con- nected in the circuit below IN INDUCTANCE COILS CONDENSERS a of the cabinet FIXED INDUCTANCE COILS CONDENSER ae eee PLATE \ VACUUM TYBE plified. The frequency GH ( INSULATION ] meter, which measures amie 1 the frequency of the 7 ‘ MEASURING CONDENSER INSULATED LEAD IN METAL SHEATH A sectional view of the measuring condenser is shown here. One plate is equipped with a pro- jection that comes in contact with the article to be measured. As the plates approach each other, the frequency of the circuit will be changed. Here the condenser is shown con- nected with the rest of the apparatus FREQUENCY METER VACUUM TUBES —*--——_- ji te pote : 100,000 CYCLES AEE THT A 101,000 CYCLES tg) ‘ae fi | | ———e 7 | lies VARIABLE CON DENSER = ee, ae 4 The diagram below shows how the current in one circuit is super- imposed upon the cur- rent in the other cir- cuit; and at the -side is shown the resultant beat note that is pro- duced by this action. The frequency of this beat note is a measure- ment of the depression of the plate in the measuring condenser Fhe. ee hee" Bn RESULTANT BEAT NOTE

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Radio Sets This Timepiece igoake people are not aware that the big government radio station at Arlington, Virginia, sends out the correct time every day. This is done by connecting the master clock in the United States Time Observatory with the radio-transmitting apparatus in the station several miles away. Every time the clock ticks, it closes an electric circuit in the radio station, and an electric impulse is sent forth. T. S. Casner has developed a clock that is controlled by the radio impulses sent out at Washington. It is corrected every day by these mysterious impulses. It can be used as a master clock, so that it will control any number of separate timekeepers. Popular Science Monthly Clock Makes Memory It Is a Seat and Training Unnecessary ATENTED by an Iowa man is a “reminder clock’ which, if it comes into general use, may make memory training unneces- sary. The face of the clock is like that of any ordinary clock, but the lower part has a scale. It is eight inches long and is marked from 1 to 90, each numeral representing a minute. A movable thumb lever is on the dial. Suppose you want to soft-boil an egg. Set this lever opposite 3 just after drop- ping the egg in the boiling water. When three minutes is up, an alarm bell rings. In photographic studios, where timing is so important in develop- ing, this clock is invaluable. Flowers in Burnt-Out Electric Bulbs ‘TAke any burnt-out lamp and a pair of pliers. Hold the metal part in a flame, and slightly turn the metal screw-cap with the’ pliers until it comes off. Then break the wire. File through and break off the crown holding the glass rod with its filaments. Just below the ridge that connects the rod with the bulb is a heavy ring of glass. Care- fully round off all corners of the heavy crown in a flame. Brass or iron strips are used to make the stand shown. Below Is a Man Pushing 100,000 Pounds HE is rolling a weight of more than one hundred thousand pounds along the track, but he would not be able to do it if the axles of the flat-car were not provided with a new type of roller bearing. The inventor of this new axle claims that the saving in power required to move the car runs as high as 50 per cent. It would be hard to believe this unless one could see one man rolling such a tremendous weight over the tracks. Under ordinary circum- stances it would take at least sixteen men. to move a car loaded with the same weight. This well illustrates the great difference between sliding and rolling friction. a Parachute ae above is a new airplane safety parachute that serves as a seat for the aviator when it is not in use. Strapped to his back in the usual manner, it is arranged so as to hang out of his way. When he takes his seat in the airplane; the folded parachute becomes a cushion. Should any accident occur, the flier has only to step out of the plane, pull the ring that opens the parachute, and descend in safety. No further adjustments are re- quired. That the parachute is a very present help in time of need, the airman is willing to testify; it is more valuable to him than the lifebelt is to the sailor. When Not Used, This Coat- Peg Hugs the Wall A NEAT little peg is fastened to the wall with three small screws. It is made in several metals, is spring-controlled, hug- ging the wall until it can be of use, and then it will hold a hat and coat with ease. As soon as the garments are removed, the peg springs back to its original position, which is a distinct advantage where the hall is narrow or where space must be conserved. Hung on a door, the peg might serve very well as a knocker; and screwed to a desk, wouldn’t it make a good paper- weight? D ~ ga a a ale Poa Go RS ea

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July, 1921 Dictating Letters Through a Horn | pctengeeconanl you are wondering what is the reason for the large horn on the desk of the business man shown above. It con- nects him vocally with his stenographer, whose desk is in the next room. When he wishes to dictate a letter, he talks into the horn, and his voice rings out of a similar horn on his stenographer’s desk. The end of each horn is covered with a parchment drum that is held firmly in place by a steel band. A taut wire is stretched from drum to drum, and across it all the vibrations caused by the voice are carried. If the wire is not taut, the device does not function properly. This contrivance did away with a great deal of running back and forth. Signals from the License-Plate ye another scheme for making auto- mobiling less dangerous. Cut the numbers out of the rear license-plate and place a piece of transparent paper in back of it. Connect up a red and a green light behind the plate in such a way that the red light will flash when you step on the clutch or brake, and the green light will flash when you remove your feet. On a dark night this will be very useful. The Lawn-Mower with the Long-Reaching Arm RESIDENT of St. They Climb Over Live Wires with This Ladder henge iy only thirty-three pounds, and with the advantage of folding into a compact load for transporting, this safety ladder for linemen is one of the newest electrical workmen’s accessories. The ladder is held out from the pole by two supports pivoted to crossbars set in the back of the ladder. There are three of such bars at the top, middle, and bottom of the ladder, and the supports may be set on any two bars desired. A treated rope is used as a diagonal brace, its length being adjustable relatively to the supports. The construction provides ample protection on a 110,000-volt line. Ribbon Woven by Hand on a Tiny Loom ERE is a small model of the usual large hand loom. It is used for weav- ing small- things—ribbon, for instance. And it has been found that ribbon made in this fashion lasts much longer than ordi- nary machine-made ribbon. Only a few shuttles are used, and the silk is brought down from them to the weaving platform. Here it is interlaced with strands from cross shuttles and then ““packed.”’ The packing consists of forcing the threads together so that the resulting rib- bon will be smooth and straight. It is said that ribbon made in this way will last for years. The same is true of lace that is hand made. Life-Boats Carry Wireless N the Olympic, which sails between Southampton and New York, two special life-boats have been added to the equipment. They are twenty-eight feet in length and will accommodate thirty-six people apiece. Both boats are motor-driven and are fitted with a wireless outfit. Under ordi- nary conditions they will be able to send and receive messages within fifty miles. Bootblack and Customer Are Separated by a Partition Joseph, Missouri, Theodore J. Kallauner, had two twelve-foot-high terraces in front of his house. Every time he trimmed them with the mower, risking his limbs, if not his life, ke became convinced that something ought to be done about it. As you see, Mr. Kal- launer did something. The long handle permits him to stand at the top of the terrace while mowing it, and the adjustable shorter section, with the slot at top for the handle of the mower, allows the mower sufficient leeway to pre- vent its jamming if sud- denly brought up at an awkward angle. This at- tachment can be used on any type of hand lawn- mower. HE bootblack in the picture on the left polishes shoes without ever seeing the face of his customer. The customer sits on one side of the par- tition and the bootblack works on the opposite side, a situation that does notencourage conversation. The bottom of the par- tition is cut away so the customer may place his feet on the foot-rests. The customer does not have to climb up tothis seat, knocking over bottles and cans on his way. The little doors in the partition are used to make change and to pay the bootblack. The partition certainly ought to be useful to the bootblack when he smears up a customer’s clean __} white socks.

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SEE Sete, BROKEN POTTERY OR STONE Plants Will Flourish Here I" you would bring the small cuttings of geraniums, fuchsias, and roses to maturity, heed the advice of the United States Department of Agri- culture. First build a window-box and cover it with glass. In the bottom of this box place some broken bits of pottery and stones. On the top of these place some clean sand free from clay or de- caying organic matter. Place the cut- tings in this, and give them plenty of sunshine and water. “Plenty of water’’ does not mean drowning them. As the roots start to branch out, the glass cover should be partly removed for ventilation. Measuring the Heat of Fruit The Blind May Now Enjoy Football pene who have lost their sight usually de- velop the hearing faculty to an unusual degree. This enables them to get a great deal out of life in spite of their apparent misfortune. A blind man probably gets more enjoyment from a concert than a seeing man possibly can. But a blind man at a football game is at a disadvantage. He can hear the crowd yell, but he does not know what it is all about. Joseph Gibbs, a Scotchman, has invented an in- genious apparatus that will enable a blind football fan to follow the developments of the game with sur- prising accuracy. Little wooden men are used to mark the various positions of the players. If a per- son with sight keeps the blind person informed as to the plays, the latter may obtain a very good idea of the progress of the match by arranging the men on his board accordingly. Popular Science Monthly How Much Zinc Is There? H°’ to test the galvanized surface of iron pipes is a new discovery. This new test will determine the weight of zinc on a unit area of gal- vanized surface regardless of convolu- tions or corrugations. Dr. Allerton Cushman has found that by collecting the hydrogen gas from any known area of surface, the weight may be deter- mined. A small container filled with hydro- chloric acid is cemented to the pipe to be tested. When this acid comes in contact with zinc, hydrogen is evolved and the gas passing off is collected and measured. It is then easy to find the quantity of zine on the surface. Goat Decoy Traps Leopard RESPIRATION chamber for bees? What is that, you ask. It is used to study energy transformations in the ripen- ing of fruit and the wintering of bees. The chamber is provided with an especially de- signed calorimeter, an instrument to meas- ure the quantity of heat produced. The respiration chamber and _ calori- meter are used in research on food storage and the arrangement has made possible the accumulation of considerable data along this line. Artificial Pearls Made in America 1 hype preted every woman has her string +‘ of pearls—artificial ones. They may cost fifty cents or fifty dollars. How are they made? By coating the inner surface of thin glass beads with a paste made from fish-scales. Formerly they were manu- factured chiefly in France. The fish-scales were bought from Russian fishermen. But during the war the United States Bureau of Fisheries developed a substitute for the Russian fish-scales. The scales of shad and sea herring have the delicate color of Oriental pearls. This silvery coating was removed from the body of the scales and made into what is known as “‘pearl essence.” The herring and shad found in Chesapeake Bay give the best. The pearl essence is a pastelike substance that will adhere to any surface. When it is smeared on the inside of thin glass beads it will harden like cement. How are real pearls formed? The present belief is that a small parasite bores its way through the shell of an oyster. The para- site is killed by the oyster, which imme- diately proceeds to cover the parasite. This covering process continues until a pearl is gradually formed. Jewelers make a distinction between artificial and imitation pearls—the former are more expensive. 68 ow is shown an Indian leopard- trap. A live goat is confined in the trap, protected by strong bars. The trapdoor is raised a few feet from the ground by a lever resting on a crossbar above, while the lower end of the lever is attached to a rod stuck into a plank, raised off the ground, inside the trap. The decoy bleats and the leopard, in attempting to get at its prey, treads on the lever and the heavy door falls into position. His next public appearance is as a captive.

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July, 1921 Courtesy of the U. S. Bureau of Fisheries Salmon Eggs Hatched by the Million T= United States Depart- ment of Fisheries is busy raising fish eggs, so that we may continue to enjoy eating fish. In the great fish-hatcheries ~ maintained by the government countless millions of fish eggs are protected every year. When they reach the proper growth, they are placed in the water to fight for a living themselves. Above you see a tray of sal- mon eggs that have been under expert care for several weeks. It is only one of many thou- sand such trays. labor ordinarily necessary for this task. A One-Man Road-Grader NCE two teams of horses and at least two men used to be required to level and grade roads. Now we have the one- man machine, which does the job in half the time and never gets tired. Like all modern devices of this nature, it is, of course, driven by gasoline. The single operator manipulates all the levers that control the cutting blades and also takes care of the engine. All the con- trols are placed at his elbow. If you live in a community where it is the custom for each man to contribute his share of labor toward keeping the roads in con- dition, it will pay the men of the neighbor- hood to get together and purchase a one- man road-grader and reduce the time and 6 Be This MaetessEuivin Grinder Cleans Castings Ae is a new departure in hand-grinding outfits. Although nothing that re- sembles an electric motor is seen, there is one present. The motor is so constructed that the grinding element, which is made in the form of a ring, is attached to the moving ele- ment of the motor. The motor is very strong, a small one of the induction type and capable of great speed. It is held in the hands and the grinding-wheel is allowed to revolve in contact with the rough castings that have to be cleaned. Let Concrete Harden Thoroughly id concrete is not given sufficient time in which to harden before it is used, it will wear out rapidly. But what is suffi- cient time? An expert tells us that ten days are barely enough. If this is extended to twenty days, the concrete will give 40 per cent better service. During the hardening period the surface should be kept warm and moist; a covering of sand that is sprinkled daily will serve the purpose. Concrete floors over which heavy hauling and trucking is to be done will become rutted and cracked if put to use before being thoroughly hardened. Carrying a Gun by a Trousers Button ERE is a gun-carrier that will minimize the chances of accidents, besides allowing the sportsman the use of both hands. It is in the form of a single suspender, fastened by a trou- sers Jutton at the back left side, from where it is drawn over the right shoulder. As you see, the suspender is composed of a strap and two springs, a larger spring in front and a smaller at the back. These springs afford the resiliency needed to prevent the gun’s hanging as a dead weight from the shoulder. The suspender holds the gun by the lock; thus the butt rests under the armpit and the barrel is pointed downward— the only safe position for a gun not in use. Coke Will Deodorize Your Icebox HOULD you put milk and cnions in the same refrigerator, the milk will soon absorb the onion taste and become very disagreeable. Butter is another substance that is quick to absorb smells and tastes. And yet, one can’t have several refrigerators. What then? Place a small box of coke or charcoal in the corner of the refrigerator. It will act as a deodorizer, absorbing all kinds of smells, and will keep the food wholesome. Especially in warm weather is this precaution necessary. The coke or charcoal should be changed every three weeks, for in that time it will have become thoroughly saturated. The Accommodating Seat with a Spring HILE this stool was built primarily for dentists, it is clear that the housekeeper, bookkeeper, and others will find it useful. One of the chief features of the stool is a hollow stem pro- vided with a ratchet for the purpose of adjusting the height. This ratchet is con- trolled by a spring handle that also serves for carrying the stool from place to place. Some one remarked that the stool seemed almost to think, so responsive was it to every least motion of the person who occupied it. That responsive- ness is due to the heavy spring that rises from the base, and which, while giving ample support to the sitter, adjusts itself instantly to any position desired.

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Look this page over: you may find just what you need

Ovens are usually large and require consider- able heating before they are ready for use. Now, however, there is a small electric oven for baking small things. It fits over an electric heater

) Keystone View Company

There is now a plug that automatically turns off the current when an electric iron reaches a temperature of 400° F. The picture shows the marks left by an iron with a plug and an iron without

Popular Science Monthly

Here is a substitute for the electric toaster. It is an alcohol toaster. A small alcohol-lamp fits in the stand and, when it is lighted, gives out sufficient heat to toast bread

) Keystone iew Company

The ravaging effects of dish- water on hands led to the invention of the _plate- holder shown above. Pin- cers grasp the plate; you dip the plate in the water, holding it by the handle If you squeeze a tube of tooth-paste by means of a thumb-screw at the right, you will get more out of it. The end of the tube is thrust through a bar that the thumb-screw turns

< ee SR URE TORE OT PEEL:

The bookcase above is really not a bookcase at all. Behind those impressive bindings is a phonograph. But why be so secretive about a phonograph?

This small stove fits in the large coal-stove, and is very useful in summer. A small fire in the large stove will thoroughly heat the small one

At all

Instead of knotting the ends of the clothesline, use the metal holder shown above. By means of a slip- catch it holds the line firmly If you fry doughnuts in very hot fat and also place them in a wire cage, your doughnuts will be crisp but not at all greasy 70 This mustard-jar has a spout from which the mustard oozes; you press a kneb at the top whenever you want the mustard to flow

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July, 1921 Keeping Up with the March of Science Facts for the man who wants to know Square Coins for Australia HE square coin is coming into use in Australia. Before long all of the round Australian halfpennies will be called in. There are two good reasons for minting square coins. They pack better when they are boxed, and very little metal is wasted when they are cut out of the sheet. In the case of round coins, considerable metal is left that must be smelted over again. A New Paper-Filling Clay A NEW clay for paper filling has been found by the research workers of the Forest Products laboratory. It is very useful in giving a printing surface to paper. In the past, all of the clay used in this country for ‘‘loading”’ paper was imported. The American clay was found in the West, and it has been found an excellent substi- tute for soap. The workers at the Forest Products laboratory found that it produced a beau- tiful grade of paper when it was mixed with English china clay. The mixture produces a more velvety surface than where the English clay alone is used. Blood Rains on Monte Carlo Ts people of Monte Carlo were terri- fied recently when the rain brought down what they believed to be blood. Superstitious persons thought that some- thing terrible was about to happen. There is a scientific explanation for nearly every unusual thing in nature. Scientists were not long in giving a reason for this phenomenon. They pointed out that it was due to the red sand of the Sahara desert. The clouds had become saturated with the sand and it was carried to Monte Carlo before the clouds precipitated their moisture. What Colors Mosquitoes Like N the world-wide battle with mosquitoes very little attention is paid to the ques- tion of color. However, experiments have proved that the mosquito has a marked fondness for certain colors, and an almost equal aversion to others. For instance, a person wearing white shoes and stockings will be bitten on the ankles once while a person wearing black shoes and stockings (other conditions being equal, of course) will be bitten twenty-five times. Ifa black and yellow dog are together, it will be noticed that, while the black dog will suffer torments from the attacks of mosquitoes, the yellow animal will be troubled but little. The experiments that determined accu- rately which colors are most liked by mos- quitoes were conducted by an English scientist, under the auspices of the Liver- pool School of Tropical Medicine, and covered a period of seventeen days. Boxes, lined with rough cloth of various colors, were so arranged that newly bred mos- quitoes, upon emerging from the water, could enter whichever box most attracted them, care being exercised to see that no box was in any way more desirable than another by reason of greater light or shadow. At the end of the test period, 108 mosquitoes had entered the navy-blue box, 90 the dark-red box, 81 the reddish-brown, 59 the scarlet box, and there were 49 in the black box. There was then asharp drop to 31 in the slate-gray box and 24 in the olive- green. Violet, leaf-green, and dull blue attracted respectively 18, 17, and 14. Pearl-gray drew but 9, pale-green 4, light- blue 3, ochre and white 2 each, orange 1, and pale yellow or khaki none at all. Houses 7000 Years Old EOPLE lived in Switzerland more than seven thousand years ago. We know this because a drought in -Greng, near the Lake of Morat, revealed the remains of a prehistoric village. The level of the lake went down to such an extent that the bot- tom was exposed in many places. The ancient dwellings were built on piles driven deep into the mud. The huts on the piles were made of wood and clay. Straw, reeds, and rushes formed the thatched roofs. Numerous relics made of stone, cop- per, bronze, and iron have been dug up from the mud. Bones of all the common animals have also been found. It would appear that the people who occupied these humble dwell- ings were civilized. Aluminum as Strong as Steel HREE small thin plates of steel will be balanced by nine similar squares of sheet duralumin, an alloy of aluminum that can now be made as strong as steel. Experiments conducted in the laboratory of an airplane company at Keyport, New Jersey, have succeeded in producing a quality of duralumin that is non-corrosive in salt water. It is of great value in the construction of flying-boats. How was the “light-weight” aluminum compound converted into a giant of strength equal to the ‘“‘heavy-weight” champion, steel? Mainly by the method of heat-treatment, annealing and tempering at certain temperatures and for certain periods, was the result obtained. Tests were conducted at intervals after the heat- treatment to show the effect of aging. It was found that, 120 hours following the heat-treatment, the duralumin stood a tensile test of 59,700 pounds to the square inch with a_ hardness. of 25.2 per cent. 71 Artificial Leg Affects Watch (5° watches lose in accuracy by ex- posure to a magnetic field. A war veteran working in a watch factory found it difficult to keep his watch right. Knowing something of magnetism, it occurred to him that the steel in his arti- ficial leg might be magnetized. He experi- mented and found this to be the case. He went to an electric-light company and had his leg demagnetized. After this treatment his watch kept perfect time. Charting River-Bottoms HARTING the bottoms of rivers and creeks is just as important as charting their courses and shore-lines. A device is used that will draw the profile of a river-bed. A few years ago river-beds were charted by sounding. The new device has few parts and it is absolutely fool-proof in its operation. The line is drawn by placing a pencil at the end of along rod. The oppo- site end of the rod is provided with a wheel that rolls over the bottom of the river. The variation in the bottom of the river is traced accurately, and by noting the depth at chosen intervals of time, the bottom of the stream may be charted. Modernness of the Ancients WE have only to turn back the pages of history to discover that the an- cients had some very modern notions. Mr. E. W. Hulme pointed out before the Newcomen Society, recently organized in England to study the history of engineer- ing and technology, that in the great Palace of the Two Axes in Crete there was a system of water-carried sewage and terra cotta socketed drain-pipes that could not be paralleled in Europe prior to the eighteenth century. Identified by Veins A hen the finger-print method of iden- tification has come into use, several other methods have been suggested. An Italian scientist has suggested the use of the veins in the hand. He has found that the veins are different in different persons. The veins are easily seen when viewed with a source of light that has no red rays. The mercury-vapor arc light is suitable. The Strongest Wood HAT is the strongest wood? Some would say oak, but African teak is much stronger. Jarrah and greenheart wood are heavy and strong, and oak is found to compare more favorably with them. Willow, poplar, and spruce are first

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aS Seba e e ~—vonoens | |

Be! $ among the light woods that find wide use. Balsa wood is the lightest wood that is known. A cubic foot of African teak weighs eighty pounds, while a cubic foot of willow weighs but thirteen pounds. When sub- jected to a strain test, African teak did not break until 855 pounds was reached. A piece of ash of the same size broke at 690 pounds. Coffee Painted to Order RAZILIAN coffee-dealers will paint coffee any color desired. There is black coffee, brown coffee, yellow coffee, blue coffee, and green coffee. The health authorities of some countries will not permit the entrance of painted coffee. Its entrance is not allowed in the United States. However, many of the South American countries prefer colored coffee, and certain states in South Africa also like to use coffee colored to suit their taste. The coloring matter is applied in big revolving cylinders provided with paddles. Each cylinder holds about six bags of coffee. Vegetable coloring matter is used. Truth about Sea-Serpents eee often bring in lurid stories about the great sea-serpents they have seen in their travels. It is safe to assume that many of these stories are manufac- tured. It would not be well to say that all the stories are untrue. An instance of a manufactured story is the one about the octopus caught by the sailors of the steamship Caronia, last April. The story had it that ten sailors attempted to overcome the monster, which put out a tentacle for every sailor. All the news- papers printed this story, which had come in by wireless. When the ship reached port, it was ascertained that the ‘‘octopus’’ would easily fit in a matchbox! Professor J. A. Thomson, lecturing be- fore the Royal Institution in London, described the giant fish that sailors have dubbed the “‘sea-serpent.”’ It is known as the oar- or ribbon-fish, since it is flat like an oar. The ribbon-fish often reaches a length of twenty feet. When it is attacked by an enemy, it shoots several feet out of the water. Its great length gives it the ap- pearance of a serpent. Dirty Bulbs Are Dangerous Be OCTRIC lights will not reach a dan- gerous temperature if the glass bulb is kept clean. A clean bulb allows the heat to radiate into the air and this keeps the tempera- ture normal. The accumulation of dust ‘and grease on the outside of the bulb tends. to- in- sulate the hot filament and prevent the escape of heat. This causes the tempera- ture to reach a dangerous degree, since this dust is often brought to the ignition point. The moral is: Keep the electric lights in your home well dusted. Sparks Cause Explosions’ RECENT premature explosion in a quarry, resulting in the death of nine men and the injury of several others, was directly traceable to a spark from a steam- shovel working under the face directly in front of the hole being loaded. This acci- dent and similar accidents on record in the Bureau of Mines indicate the neces- sity for pointing out the dangers in quarries of explosives from sparks emit- ted from steam-shovels and locomotives, and making recommendations for greater safety. In the Canal Zone, a steam-shovel un- covered a misfired charge of dynamite. While the dynamite was being picked up, the steam-shovel continued working near by. A spark from the shovel set fire to some loose dynamite spilled on the ground from the broken cartridges. This fire was transmitted to a hole that was being loaded close by, and caused a premature explosion. One man was injured. World’s Longest Penstock FULLY, Switzerland, has a hydroelectric plant that receives its supply of water from an Alpine lake seven thousand feet above sea-level. The plant is two thousand feet above sea-level, and the water drops five thousand feet before it finally reaches the wheels in the power-house. A long steel pipe, or penstock, carries the water from the upper level to the water- wheels in the power plant, where twelve thousand horsepower is generated. When the water reaches the end of its long jour- ney, it is traveling at a speed of 590 feet a second. This is the longest penstock in use in the world. Uses of the Coconut-Tree HE inhabitants of the Dutch West Indies depend almost entirely upon the coconut palm for the necessities of life. They make use of every part of the tree, from the roots to the leaves. Roots are used in the preparation of medicine, and the hard wood is used in the construction of homes. The sweet sap of the tree is made into sugar and the big leaves are used to make baskets. The stiff ribs of the leaves are made into brooms, and the undeveloped ribs make a delicious dish when properly prepared. The nuts are used for medicine, when partly ripe, and the milk makes a good tonic for certain ills. The husks of the nuts are shredded and made intorope. The hard shells make good cups and fuel, and the meat of the nut is an excellent foodstuff. Traffic Laws for the Sky i ipa YORK city has already set down rules for traffic in the sky. ‘“‘Drive to the right”’ is one of them. Aviators must also keep two thousand feet above the city, except when landing at places especially provided for that purpose. Nothing may be dropped from an air- 72

Popular Science Monthly plane, and stunting is absolutely forbidden. In a case of forced landing, it must seek an open space where it will not endanger life or property. Lighter-than-air machines have the right of way over heavier-than-air machines. Violation of any of these rules makes the aviator liable to a fine of fifty dollars or a jail sentence of one year. Of course if there are air laws that can be violated, there must be an air police force to see that the laws are obeyed. Why Not PerfumeYour Food? PERFUMED cookery—that is the latest novelty in the preparation of food. It has been tried in Paris. Chicken with lily- of-the-valley sauce and veal cutlets with old rose! Jules Mainstave, the inventor of the new perfumed dishes, claims that the high purity of manufactured perfumes makes them perfectly safe to use for this pur- pose. But how appetizing do you think the odor would be? Would it appeal to a hungry man as does the aroma of roast beef or broiled steak? For poets, musicians, and actors, prob- ably yes; but for hungry men—no. Wire Mesh for Roads T= British army in Egypt has used chicken-wire in the construction of roads. Loose sand was smoothed and leveled and then covered with chicken-wire, which was firmly pegged down. The passage of troops or motor trans- ports seemed to affect the road very little, while the passage of animal-drawn vehicles damaged the improvised road badly. However, it was possible to make repairs quickly and the road was easily kept in good condition. Of course this wire-mesh road was purely a temporary expedient for the military. The old Romans still hold the palm as the champior. road-makers of the world. Many a foundation of the roads they made is still in use in Europe, the surface alone being modern. How Copper Is Hardened ANY inventors have labored inces- santly trying to harden copper. Their research work has been in vain. The hardening and tempering of copper was a process that was believed by many to have been a lost art—presumably lost by the Egyptians. Copper is hardened to-day, and there is absolutely nothing mysterious about the process. Mechanical working will produce hard copper. Hard-drawn copper is available as well -as hard-drawn copper tubing. The process of drawing this cold copper through a die hardens it considerably. When copper is alloyed with other metals, it is also hardened and great quantities are used in the workaday world.

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~~. FF a FF i wer ™ fu 2g- er. he ba ve she . iS she ard ble ng. per her eat lay July, 1921 This is both a_ screw- driver and a hammer. As a hammer it is useful for small work and as a screw- driver it is all that can be desired. It is of steel When this triangular “drill’’ is placed on a milling machine, it is able to bore square holes of practically any size. The body is triangular in shape and it cuts fast and accurately Combination speed-in- dicator and stop watch. The ordinary speed in- dicator or “revolution counter’? must be used with a watch. An en- terprising manufacturer has combined the two _ A tool-holder without a set screw. Only a very small piece of tool steel is needed. This is held firmly in place at the tip of the tool These large storage-tanks for enamel keep out the dust and dirt, so that the mixture is held at the proper specific gravity. The big tanks furnish the supply for a large automobile factory TWO-CHAMBER NOZZLE i Here is a mixing nozzle. It is connected with a source of two liquids. After passing through the spiral members they meet in the mixing chamber When a switch is half turned, the switch tongue is liable to be broken or split by the trolley passing over it. This switch is held securely, either half turned or straight, with a spring and a cam 73 Here is a heavy knurling ma- chine that produces a knurled surface on work that does not need to be placed between cen- ters. It is power-driven and the operator manipulates only the lever Do It with Machinery © Some of the labor-saving appliances pictured below may help you in your work The man is using pliers that have round grips for working with round ob- jects. Ordinary pliers are unsuitable for round SELF-CENTERING REAMER Above is shown a floating tool-holder. It holds a reamer in the lathe. When a hole is ‘‘reamed’”’ out, the reamer must fol- low the hole. This holder causes. the reamer to do this RIVET HOLES SEPARABLE NALF LINK } RIVET HOLES Should a link in a chain break, a new one can be inserted with this device in less time than it takestotell. Itisa very practical ‘‘miss- ing link’’

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Mud-Guards to Protect the Man on Foot Inventions submitted in a French contest In muddy weather a metal disk, with brushes along the edge, is attached to the hub of each wheel. Thus the mud is caught in the brush The guard, in this case, is made of rub- ber. If you have any doubts about its abil- ity to prevent the mud from. shooting outward, look at the disk of the wheel; it received all the splashing that the pedestrian was spared gee RRAE Ie tA aR YE a LO PYRE ILS If you look closely you will see that there is a rubber shield along the outer rim. This shield is another type of mud- guard for protecting the passer-by Photographs © Kadel & Herbert Muddy water hits this metal protector with such force that it shoots out ’ backward. The man at the side is saved, but how about the one who steps out behind the car? Popular Science Monthly Here is a mud-brush that is attached by wires to the hub. The spokes of the wheel show through; hence the brush is not con- spicuous. It catches all the mud that the regular mud guards at the sides of the car fail to get Four-Cycle Engine Piston-Valve HE valve shown in the picture is intended for a four- cycle internal-com- bustion engine, al- though in many respects it resem- bles the slide-valve of a steam-engine. It controls the intake, compression, pres- sure, and exhaust strokes of the engine, and contains fewer parts than the pop- pet valves in present use. The cylindrical valve-chamber is made integral with the engine-cylinder casting. Two cylin- der heads on the piston-rod of the valve are so spaced that the chamber be- tween them alternately receives the gas from the intake port, or the ex- haust gas from the engine. The move- ments of the valve are guided and positively determined by a cam, the EXHAUST PORT Noiselessly this valve, which has no springs and is operated positively by a cam, controls intake, exhaust, and pressure of gas in the engine cylinder raised margin of which engages be- tween two rollers at the end of the piston- rod. There are no springs and few movable parts in this valve. Its action is positive and its move- ~ ments are always accurately timed. As there are no springs, the valve operates noiselessly; and as there is no spring pressure to overcome, there is a considerable saving in the power neces- sary to operate the engine. Practically all wear is confined to the cam, which con- sists of a single piece and can easily be re- placed by a new one from time to time. In the accompanying illustration the cylinder is shown as an integral part of the engine casting and placed parallel with the engine cylinder. 74 This Oil-Cup Makes Lubricating Easy UBRICATING an automobile is 4 extremely messy and disagree- . &§ able work. The unpleasant features of this work are reduced to a minimum by the force oil-cup illustrated below. To fill the cup, lift the slidable cover until the filling hole in the container is exposed, fill the reservoir with heavy oil by means of a squirt-gun, and push the cap down so that the opening is closed. When the cap is pushed down, the oil is forced under pressure to the parts requiring lubrication. The cup is dirt-, dust-, and rust-proof. SLIDING CAP FELT WASHERS “—~TO BEARING — >> This oil-cup is easy to fill without soil- ing the hands, and by pressing down the. cap the oil may be forced to any bearing or other part that requires lubrication

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Tr is i is i, 1e July, 1921 Automobile Wheels Are Now Made of Plywood HE newest development in auto- mobile and motor-truck wheels is one made of layers of wood, glued to- gether under great pressure. The wheel is of the disk type, and is com- posed of seven thin circular slices of wood, the grain of each piece running counter to the next one. This process of lamination makes the complete disk into a strong, non-separ- HH], LAMINATIONS able, non-warpable, she but resilient whole, ‘i — which is claimed to be 1 At able to withstand 100 per cent more side strain than the spoke wheel. The weight of the new wheel is ap- proximately the same as the spoke wheel. Any standard de- mountable rim can be used the same as on the spoke wheel. The { RIGHT-ANGLE m. TIRE-VALVE D STANDARD RIM, hub construction is the same, except that a right-angle tire- valve is provided. Motor-trucks and automobile wheels are being con- structed of ply- wood Motor-Polishing the Car RACTICALLY no “grease” is necessary when this new polishing machine is put to work. It works fast and covers many times the area that could be covered by a man using a polishing-cloth. By its use one man can polish seven cars a day. Compressed air is used to drive the mechanism. This propels two feet, or “kickers,’”’? which work in opposite directions. All of the parts are made of an aluminum alloy that makes the machine light and easily handled. One man can polish seven automobiles a day with this air-driven polisher This doctor has just called up his office and is recording the calls that have come in The top of the car will serve for the placing of the wireless antennae re- quiring merely a post at each corner Equip Your Car with. Wireless NY enclosed automobile can now be equipped with a wireless tele- phone outfit. The instrument on this automobile will work successfully up to five miles and use only a small part of the automobile battery’s current. You can hear as plainly as over the tele- phone. - The young men in the pictures above found that it is not necessary to have antennae high up. Their experiments proved that the wires stretched around the top of the automobile were success- ful in picking the sound waves out of the air and they then solved the an- tennae problem by running four paral- lel copper wires around the top of the car on six-inch posts fastened to the corners. They grounded the set to the automobile engine as is done in air- planes. It is an easy matter to sit in a car thus equipped and ring up one’s home, provided you are within the five-mile zone. Putting a Camel in the Automobile LLING O. WEEKS, a professional aviator, worked for five years on his device for automatically keeping the automobile radi- ator full of water before it was perfected. It consists of two main parts, a tank anda float-controlled valve, con- nected with piping. The tank is placed ver- tically at the bottom of the dash under the engine hood and is piped to the radiator overflow pipe. The tank thus catches, condenses, and holds all steam and water escaping from the radiator. The float-controlled valve is at- tached to the top tank of the radiator under the engine hood and is connected by tubing with the intake manifold of the motor. As the water-level in the radiator lowers, the float-controlled valve opens, permitting the motor to create a partial vacuum in the top of the radiator and draw back sufficient water from the vertical tank to refill the radiator. As soon as the radiator is again filled, the float in the valve rises and shuts off the motor suction until the water again lowers in the radiator. The vertical tank carries a reserve 75 TO INTAKE MANIFOLD H hameeien RADIATOR CAP OVERFLOW TO TANK When the radiator runs low, but before the water is exhausted, a whistle warns the driver supply of water and is fitted with a whistle that, when it blows, warns the driver that the supply of water in the tank is exhausted. «This occurs before the radiator runs low, so that the engine is always protected against overheating due to loss of cooling water. In creating the suction in the upper part of the radiator, the float-valve also feeds into the intake manifold a very slight amount of moisture, which tends to increase the engine power, when converted into steam by the high explosion temperatures, as well as to prevent the formation of carbon with all of its attendant harm to both the spark-plugs and the cylinders.

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a - EO ROR LIT LE OE OTR IE SET PET SRS pr POEM Hate abe Sh ATT TIE TRAE See er eeernnrerecars ee re a ARETE on RRS ees in hata Fen AS A in 0 RET TIT RR. Items of Interest to the Automobile Owner and Driver Popular Science Monthly Here is a tire-chain device te . that does not pull the chains but connects them. A double-lever tool forces the chains together, leav- ing plenty of play for Z locking them : The air-chuck slips over the air-valve, gripping securely and locking itself on, avoiding waste of air from the compressor. To release it, you push up a small lever CAST-IRON SPRING~- RRESSED PADS In treating scored and out- of-round cylinders, this lap- ping tool is very efficient. Two springs assure pressure of the pads against the cylinder wall Heretofore accelerator pedals have been made for men’s boots; here is one made especially for the smaller shoes of women; it can be used on any car MASTER CYLINDER ™® BRAKE PEDAL FRONT Oll- OPERATED PI PES — In replacing the broken cells of storage-batteries, the old-style steam-box has been displaced by a battery steamer that generates steam in four minutes. It is oper- ated by gas or kerosene, and the steam is conducted to the battery by hose DISTILLED WATER XY An American brake that is operated hydraulically instead of by rods and levers. The four-wheel brake en- ables the driver to stop a car in half the usual length This steamer not only takes care of the steaming processes required for the bat- tery, but the tube at the left of the steamer goes up into another container, creating distilled water for the service station 76 COMPRESSION FLANGE __ VALVE-SPRING A tool designed especially for removing valves when they are located in the head of the motor instead of in the side. The compression lever can be attached at different points of the upright A fan, attachable to the hub of metal wheels, that consists of three paddles, which throw the air against the steel rim, cooling it Y HIGH AND LOW) WATER GAGE Mounted on the instrument-board with the speedometer and clock, this device warns the driver when the water in the battery is low or when the battery is run down

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ly July, 1921 When You Want Expert Advice About Your Car N these pages of ideas about automobiles ered, and we invite you to write to the Auto- and motor-trucks the Popular Science mobile Editor and let him advise you. Monthly endeavors to help its readers solve If you wish to know more about the devices problems of maintenance and repair. But pictured here, or if you want to ask questions, there must be special cases that are not cov- write. Some answers are given on page 79. oT ig If ir ‘o a On the left is a new funnel cap. A wisp of steam warns when the engine becomes over- heated. The funnel as seen on the right may An anti-theft device at- be swiveled to receive tached to a front wheel, a supply of water pads protecting the wood- work. It is a noise-mak- ing device, caused by the lock coming in contact with the roadway This is said to be the largest motor-truck ever made. _ Al- though its capacity is no more than three tons, it can carry at one time two hundred and sixty barrels, arranged four rows high and five wide ED for | Fitting into a recess on If you are subject to icy the inside of the left front neuralgia caught from the door, the tool-tray here “drafts’’ on the neck, buy de. shown makes the tools one of these new neck an instantly accessible wind-shields, and slip it ent beneath your collar Attach this device to your al spark-plug to increase the ‘ss “ Made of pressed steel, this engine power by sending vaih collapsible pump is easy an electric current through to operate owing to the system that equalizes the leverage with the pressure the spark-plug in one in- tense spark instead of in many weaker oscillations When the wheel squeaks because of loose spokes, there is a com- pound that is claimed to per- manently tighten the spokes A new make of car provides a place for stowing away the side curtains of an automobile in the back of the front seat All kinds of electrical equipment may be tested by the instruments contained in this new battery-testing stand which is the invention of a Chicago man 717 poe 7yr }. tang

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a RAHN AT Saray Pee TS sage dntaiieaethanicas: cieendumer dames e-alerts ai a ee ee ps . = By BF, Se, f 5 A spray-tank carried on a trailer is efficient in large orchards; the machinery is driven by the tractor motor FILLER /PLUG Spraying the Fruit-Trees 4, ae f i toy INLET STRAINER | rom a Trai HE combined tractor and spray- ing-machine pictured above has been used with great success recently in large orchards of the West. The spray-tank is hauled on a trailer in the rear of the tractor, while the spraying machinery, driven by the tractor motor, is attached to the forward end of the tractor. This machine is more powerful than the older devices operated by gasoline motors. Orchardists maintain thatthe fluid thus forced on the trees in a fine spray is more effective than when it is applied in drops. The hybrid machine is considered practical for use, especially in large commercial orchards. HINGED AIR TUBE BUBBLE 7.0. DEFLECTORS Vibratory Motion of the Car Feeds the Oil. ECENT attempts of automotive engineers to eliminate grease from chassis lubrication have brought out many different types of thin oil lubricators, of which that shown at the right is the newest. i. By feeding to the fuel mixture a supply of air saturated with water vapor, it in- creases the engine power and reduces the.carbon deposit This device works on the splash sys- tem, the vibration of the car forcing a small amount of oil over the edge of a reservoir in much the same manner as cator works on water is spilled out of a saucer. Oil is ll —. not fed to the bearing when the car re- ce li fl mains stationary. The feed when moving car forc- moving, however, is directly propor- ing oil in small tionate to the amount or degree of wee ver etimetinn the reservoir As shown in the accompanying sec- tional view, the oiler consists of a cylindrical bowl with a screwed-on cap. As the cap is screwed down it forces down a rod in the center of the bowl. This rod extends through the bottom of the bowl and acts as a valve to permit the oil to flow down through a plug into a saucer- shaped reservoir, which with the plug forms an automatic level seal that prevents the oil from flowing over the edge of the saucer when the car is standing idle. When mov- ing, the oil is splashed over the edge of the saucer and down into the bearing, more oil from the cylindrical bowl above flowing down and taking its place in the saucer. BEARINGS This oil lubri- 78 Popular Science Monthly | Automobile Fuel Moistened NE of the best worked-out examples of the several devices now on the market for humidifying the air mixed with the fuel vapor fed to the automobile engine is shown below. Its purpose is to feed to the fuel mixture an auxiliary supply of air uniformly saturated with cool water vapor, which tends to increase the engine power when the water vapor is turned into steam at the moment of explosion and to reduce the amount of carbon deposit through a chemical combination of the oxygen of the water and the car- bon into a gaseous product of carbon monoxide or dioxide. Its special feature is a floating air-sprayer, the purpose of which is to supply the water vapor at a uniform rate. This is accomplished by spraying a stream of air into many fine bubbles at a constant depth below the surface of the water so that these bubbles always rise through the same depth of water whether the water container is full or nearly empty. This tends to effect perfect vaporization. One filling of the water-con- tainer is sufficient for four or five hundred miles of average driving. The apparatus consists of two main parts—the water-container, which is mounted on the front side of the dash under the engine hood, and a needle-control valve, mounted on the panel-board within the driver’sreach. The filling trough at the top of the container is designed to permit the convenient pouring of water from any position. The container is read- ily drained through a petcock at the bottom. OUTLET ae AIR PIPE —— —_——______ [omy ? VALVE-STEM PERFORATED AIR TUBE ~~ AIR PIPE TO ENGINE —) The Amphibious Tractor T first glance the object in the stream looks like some strange boat. It is one of the new government tractors for carrying a 75- millimeter gun. The Ordnance Department calls this creeper tractor the water-nymph. The ignition wires, distributor, and spark-plugs are waterproofed with a special compound and the carburetor is water-tight. The eight-cylinder engine exhausts directly into the water. The vertical pipe on the side is an extension of the intake pipe, and any stream of less depth than the height of the pipe opening can be forded. The water-nymph, so called because it can ford. a stream; it is a creeper tractor mounted with a 75-millimeter gun

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ral air is an ter oks the 75- ‘per res, fed r is ists n of han July, 1921 What Is Your Running Alinement? To reduce tire wear, measure the action of your automobile wheels HEN automobile wheels are out of proper alinement, the result is excessive tire wear. Most corrective methods, however, have measured the alinement only when the wheel was stationary. This is not sufficient to reduce tire wear, because the tire does not wear when the wheel is stationary, and because the true or running alinement may vary considerably from the station- ary alinement. Millions of dollars in excessive tire wear have been wasted in the United States, because there has been no convenient method of meas- uring running alinement. Wheel misalinement occurs as a result of wear in the steering mechanism, wheel-bearings, ete. If wheels are allowed continually to bump into the curb, misalinement is produced, as well as when improp- erly adjusted tie-rods connect the front wheels. It was by noticing the sand pushed to one side of the wheel track when running a car over a beach that the full significance of the difference between stationary and running alinement was realized, and led to the invention of an instrument to SENDWISE MOVABLE ALINEMENT PLATE When an instrument of this kind is placed near the door of a garage, every car enter- ing must pass over it, and if the wheels are out of alinement a bell rings MASTER AND ALINEMENT ALINEMENT PLATE TWO SETS OF ROLLERS” Showing the mechanism inside of the alin- ing machine. As each wheel passes over the plate a set of rollers transfer to the dial a faithful indication of its alinement measure a car’s running alinement. The instrument, consists of two parts, a plate over which the wheel is run, and a dial to indicate the de- gree of misalinement. It may be used with cars having either pneu- matic or solid tires, and is made in a large size for permanent location in the runway of a garage, and in a small portable size for mechanics. Both sizes work on exactly the same principle. The part over which the car wheel is run consists of two plates, the upper one of which moves over the lower on two sets of rollers as the wheel passes over it. The movement of the plate aetuates a lever connected with the master hand on the dial, which in turn operates two smaller hands, one moving to the left and indicating how much the wheels are toed in, and the other moving to the right and indicating how much the wheels are toed out. The hands remain stationary in the positions as set by the master hand until the reading is taken, when they may be returned to zero by pressing a lever. The top plate and rollers are au- tomatically brought back to their original positions. Why Disk Clutches? Q.—What have been the fundamental causes behind the growth in popularity of the wet and dry metal disk clutches in auto- mobiles today as compared with the type used almost exclusively several years ago?— D. F. G., Reading, Pa. A.—The advantages of the multiple dik type of automobile clutches as compared with the cone design may be briefly summed up as greater ease and smoothness of operation; less liability to get out of order; greater compact- ness and a reduced spinning tendency due to less inertia of the driven member due to lightness and small diameter. Block Engine Castings Q.—What are the advantages and disad- vantages of casting automobile engines in block as compared with casting them singly or in pairs?—K. L. H., Peoria, Ill. _ A.—Engines with four cylinders cast in one piece are more compact and generally lighter in weight than when cast singly or in pairs. Because of the greater compactness, there is greater engine strength and rigidity. Because of the large size of the one casting as compared with the single cylinder, greater care must be exercised in the actual foundry or casting work. If one cylinder is cracked or out of true in a four-cylinder block, the entire block Write to Us About Your Motor Troubles If you have a motor-truck or automobile problem, let the Automobile Editor solve it must be scrapped. Greater care must also be exercised in designing the water manifolding around the cylinders so . that distortion due to unequal heat dissipation is eliminated. Proper Brake Clearances Q.—What fis the proper clearance to allow on external-contracting automobile brakes? —F. G. G., Cleveland, Ohio. A.—On most brakes the clearance generally allowed varies from 1/64 to 1/16 inch all around. It is necessary that the clearance be the same all around the drum to prevent binding or rapid wear of the brake lining. Irreversible Steering-Gears Q.—What ie meant by an “irreversible’’ steering-gear?—G. F. O., Yonkers, N. Y. A.—An automobile steering-wheel is said to be “‘irreversible’’ when the same power exerted to turn it at the wheel will not turn it when applied to either one of the front wheels or when the steering-wheel is not turned by the ordinary road wheel impact. The de- gree of “irreversibility” is determined by the reduction between the steering- worm and -gear. The greater the re- duction, the less reversible the gear. When Trailers Pay Q.—How can you tell whether or not it will be an economy to haul a trailer behind a motor-truck in certain kinds of work in order to deliver greater loads?—H. J., New York. A.—Each proposed installation of trailers must be studied alone. Speed, roads, and grades are the three most important factors to be considered. “When Motor-Truck Trailers Pay,” published on pages 79, 80, and 81 of the Popular Science Monthly for March, 1921, will enable you to decide. Cooling the Engine Q.—What are the advantages and disad- vantages of the air-cooled car as compared with the water-cooled type?—J. S., East Orange, N. J. A.—The advantages claimed for the air-cooled engine are its light weight; freedom from leaky water connections and frozen radiators and pipe lines, and higher engine efficiency or fuel economy by reason of the high operating tempera- tures, tending to vaporize fuel more completely. Among the disadvantages claimed by those who favor the water- cooled engine, are the need for greater care in operation; tendency of pre- ignition when the engine is run for an extended period and at high speed, and lubrication troubles. 79:

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ae Protecting the Battery from Mud and Water N some cars the battery is exposed to the mud and water thrown by the wheels. On such cars the top of the battery quickly becomes covered with mud. That this condition does not tend to lengthen the life of the battery is shown by the fact that some of the manufacturers provide a means Keep your battery in good condition with this little cover; it will save money of preventing mud and water reaching the battery, by placing a cover over it or plac- ing it-under the seat. Owners of cars with unprotected bat- teries may protect them in the following simple manner. Fasten thin boards or pieces of tin to the bottom of the foot- board, so that the battery is surrounded by them. These should be long enough to reach 6 in. or more below the top of battery. All the mud thrown by the tires is then intercepted before it has a chance to reach the battery.— PAUL GorRTON. Bent Fenders and Bodies as Good as New "THE tool shown in the appended sketch was devised for the purpose of removing bulges and bends in the fenders and bodies of automobiles with the least damage to the paint and without the tool marks so com- mon to jobs done with the usual hammer and blocks. This tool consists mainly of two steel forgings about 4 ft. long, linked together at one end with a crossbar at the end of one OPERATING , aa" SLIDING BLOCKS AM iy —> essa PADDED BLOCK Bent fenders make a car look old; keep the fenders on your car in shape with this simple tool part. A screwbar midway of the length of the forged arms, with a threaded nut and lever, has for its purpose the closing up of the arm ends. Padded wooden blocks are arranged to be made adjustable. In use the single block is placed on the reverse side of the bend or buckle, which is the place of least resistance, and the opposite blocks at the extremities of the bend. Pressure applied through the screw then returns the meta to its former condition, frequently with but little resort to additional means. The steady application of the pressure and the pads on the blocks protect the paint without further disfigurement to the body.—G. A. LUERS. An Old Piston Turned into a Lathe I" became necessary, a short time ago, to reface the valves of my automobile engine, so I decided to transform an old automobile piston into a lathe for refac- ing the intake and exhaust valves. I drove the piston-pin out on one side, made a strap to go around it and engage in the valve-stem key-seat so that the valve could not move endwise. Boring two holes in the top of the cylinder, I fastened it to blocks. I cut out An old piston can be made to serve as a lathe; it is a useful addition to the garage two sides to make room for the pulley and attached a tool-rest. A facing tool or a small flat file, ground on a slight bevel, could be used.—HIRAM BRACE. How to Repair a Cracked. Water-Jacket Preteen water-jackets should be promptly repaired by putting a patch over the crack. To prevent the extension of the crack under the patch, a tension patch should be applied, the screws of which are set at an angle of about 10 degrees to the surface of the jacket. The holes for the screws that hold the patch in place should be drilled with great care at an angle of about 10 degrees. When the screws are put in and tightened, they will draw the edges of the broken parts together, making a secure joint and pre- venting any extension of the crack. The use of countersunk head screws is advisable, as this affords a seat for the screwhead.—G. A. LUERS. CRACKED CYLINDER HEAD PATCH DRILLED AND USED AS ATEMPLATE WLU) TENSION METHOD A cracked water-jacket is a knotty problem to the motorist; here is a simple way of making a repair 80 Popular Science Monthly Let the Automobile Pull Itself Out of the Mud FROADS in the country are by no means always in perfect condition. Every driver of an automobile who has attempted cross-country tours, especially after an ex- tended period of rain, knows that the / Another way of getting out of the mud: hitch the car to a tree and the motor does the rest danger of becoming stalled: in the mud is ever present. The device shown here, which is the work of an inventor in the southwestern part of Missouri, where muddy roads are frequent, offers an excellent suggestion. In front the car has a spool or spindle on a horizontal shaft on which a long piece of cable is coiled. The spool can be rotated by a worm and gear, driven by the engine-’ shaft: When the automobile becomes stalled in the mud, the cable is unwound, the free end is fastened to a tree, telegraph- pole, or some other fixed object. The engine is coupled to the worm shaft and started, winding up the steel cable, thus effectually pulling the car out of the mad.—C. A. BRIGGs. Repairing a Broken Rear- Axle Housing eo the rear axle housing of my automobile broke, I repaired it in the manner here described and illustrated. Before beginning the repairs, I wired the broken parts together by drawing wire STRIPS SCREWED ON HOUSING MACHINE = SCREWS BRAZE AROUND BREAK AND ALONG STRIPS IRON STRIP — mk 40 r9 9 9 9 Of I% V4 HOLES~ } — * ; a F eeemecerim sername PN Y6, One of several methods of repairing a broken rear-axle housing is here illustrated tight from one brake drum to the other. Then I drilled and tapped several series of 14-in. holes in the housing, three on each side of the break for each of the strips that were intended to hold the broken parts together. The strips, of which I used four, were 8 in. long and %% in. wide and 3/16 in. thick. In each of the strips I drilled six holes 4 in. . in diameter to match the holes drilled in the housing. The strips were screwed to the housing—and then I brazed all the way around them.—A. J. WIESINGER. Popular Science Monthly

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ly ns Ty ed X= he d is the cern are eon e of ated rine-" mes und, aph- haft able, t of re | my n the i the wire CHINE REWS STRIP ill 1% —U ON Yo. Fa -re other. ries of 1 each s that parts were 8 thick. Yin. | in the to the e Way « July, 1921 Make a Door-Check and Save the Wall | Fanarced constructed and very practical is this door-check to prevent the knob from coming into contact with the wall. It may be made from a block of wood (prefer- . ably soft) 4 by a 3 by 1 in. At ig the top cut out — a piece 1 by 34 . in. and \ in. deep. Cut the block in the shape shown in the illustration. Take an old rubber heei and cut from it a block of about 34 to 1 in. by 3%in. Glue this into the slot and paint the door-check the same color as the wainscot- he |" To prevent a door from injuring the . ' wall ing to which it should be at- tached by screws.—M. J. SILVERSTEIN. A Drain-Spout Made from an Old Tire paom a quarter section of an old tire I improvised a drain-spout as shown in the illustration. I selected the best quarter of a tire and cut it carefully so as to obtain asmooth sec- tion at right angles. One end of the tube was slipped over the lower end of the leader pipe QUARTER and securely wired q SECTION Of to it. The spout =~ TIRE was in every way as % S satisfactory as one made of tin orth galvanized iron.— fow the drain-spout LEON ADELMAN. was constructed WALL OF BUILDING Building a Goofah from an Old Auto Tire esos you not know what a goofah is, I will inform you that it is one of those primitive boats of circular form used in the Orient for carrying luggage, goods for the market, and even persons on the rivers and in quiet shore-protected parts of the sea. The illustration clearly elucidates the con- struction of this boat. An old tire, which, however, must be air- tight, forms the floating frame or gunwale. i, . Although this boat resembles a_ large drinking-cup, it is perfectly safe in smooth water \ ! == ll July, 1921 The body of the boat consists of water- proofed canvas that is sewed to form a bag of the same diameter as the tire and deep enough to accommodate one person in a crouching or sitting position. The upper part of the canvas bag is lapped over the tire and securely sewed. The bottom of the boat is formed by a piece of board cut round. The lower edge of the canvas bag is lapped over the edge of the boat, and cemented to it. The boat is collapsible and light enough to be carried on long trips.— JAMES A. MONTGOMERY. Workbench Cast-Offs Make a Turn-Buckle F a turn-buckle is needed, one can be constructed from parts found about any workbench. Procure a stove-bolt of the size desired, fit it with a nut, and find two large washers that will slip easily over the bolt shank. Drill two holes in each washer, exactly opposite each other. Then make two loops STEEL WIRE Ms WASHERS— rd STEEL WIRE. A long stove-bolt with its nut, two washers, and two ends of heavy steel wire are the constituent parts of this improvised turn-buckle - of steel wire about the shape indicated, slip the two ends of these loops into the holes in the washers and rivet them. Assemble these various parts as illus- trated in the picture above and the turn- buckle is complete.—L. B. ROBBINS. One Method of Removing Fumes from the Air I paernnay and buildings in which fire- engines are housed invariably contain air that has been vitiated by the fumes of combustion from the exhaust of the engine. LUMA \\\)i he LIP OVER ” ws HOSE TO S CAP. EXHAUST PIPE OF ENGINE OUTSIDE y OUTLET Y 4 FLOOR~ —H 2" PIPE FASTENED TO CEILING CELLAR ; The ventilator here illustrated will pre- vent the fumes from the exhaust of the engines from poisoning the air in the garage or engine station Here is a method to remove the noxious gases from the atmosphere. A 2-in. pipe should be laid under the floor and past the outer wall of the fire- house. The end of the pipe inside the fire- house should have an extension at right angles through the floor. This ext@nsion should be placed so that it penetrates the floor at the place immediately underneath the exhaust of the engine. The pipe is connected with the exhaust by a rubber hose that slips off the exhaust whenever the fire apparatus leaves its quarters. The end of the pipe outside the building may be extended to the roof, or to some place high enough to produce a draft that will carry off the gas. $1 Making a Swing from a Discarded Tire WE all remember the swing hung from a gnarled‘apple-tree out on the farm where we spent our earliest summers. A modern equivalent of the old-time swing is made from an old discarded automobile , = re Pore Boys and girls will get a great deal of fun out of a tire swing tire, provided it is not in too bad a con- dition. The tire forms a more comfortable seat than the narrow board of our early ex- periences, and the young rider can cling comfortably to the rounded sides. Suspending the tire from a single rope permits of a variety of gymnastics, the rotating motion being very popular with the small boy and girl—LEoNn ADELMAN. Rubber Mats from Pieces of Old Tires pd you have some old automobile tires, you can make good use of them by making one or more mats for the porch or front hall. First, make a rectangular frame of heavy iron wire. Galvanized wire is better than . é P LIGHT PIECES OF plain wire, as it WIRE. OLD TIRE will not rust. Onn nna Then strip all the AMMO Inn heavy rubber a! parts from the PJWUWUIUICICICICICS fabric of the tire and cut the rub- ber in pieces 1 in. square or larger, also cut an equal number of small- er pieces 1% in. square. Punch twosmall parallel holes through each large and small square and string them, alternating small and large pieces, on two wires. Twist one end of the wires around the heavy wire of the frame, stretch them across, and make them taut by twisting the other end around the oppo- site side of the frame. According to the size of the frame 10 or 15 rows like this will be required which should be so spaced that about 14 in. space is left between the pieces of rubber. It is advisable to use galvanized iron wire also for stringing the rubber pieces. The accompanying illustration shows the ap- pearance of the mat.—E. T. JONEs. rR NEAVY WIRE Old automobile tires may be utilized for making this mat i } f i i ane SNE ETE SE /

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te ——s —o ais " Ree Gh aT : : > —— ee ne ere Se nN sce mE AS aig RENT - - = — coment : renee te em fh How to Make an Adjustable Head T-Square OU can make an old T-square into a most useful adjustable head instrument, as shown in the illus- tration. First remove the blade from the head and true up the edges with a fine set plane, sandpaper, and a true straight edge. Then attach a square plate of thin brass to the end of the blade by four small flat-head machine screws or copper rivets, being careful not to split the blade during the operation. Then drill plate, blade, and head, making a hole about 4 in. or 3% in. in diameter, to take a short Here is a way to transform your fixed head T-square into an adjustable one that can be used at any angle boit and wing nut. Place a washer under each end of the bolt and the device is complete. The blade may be trued up again at any time by removing the wing nut and head.—H. H. PARKER. Improvised Eyeglass Chain from Paper-Fasteners STRONG wind, such as is en- countered on a boating-trip or automobile tour, makes one wish for some means of holding the glasses on. It was just such a strong wind that caused this emergency. chain to be evolved. One man happened to havein his pockets some fasteners, one of which was straightened out as shown. A loop was then bent in one end with the aid of the automo- bile-kit pliers. sy PARR a ae then shaped by aot hand to fit the 7) wearer's ear. wap Four fasteners oma were found to se be long enough to stretch from the earpiece to the glass. This will keep the wind from blowing off your glasses Would You Like Extensions on Your Telephone? HEN a private desk-type tele- phone is installed, the instru- ment is placed as conveniently as possible. Yet itis often desirable to telephone from several points. An old audion socket and bulb can be made into a good extension by connecting the three wires from the telephone to i:2 bulb base and three wires from the bell box to the sockets, with a socket located at every point where it is desired to locate the tele- AUDION SOCKETS RCD YELLOW GREEN a [ lal ; a o lo} Z. These extensions may be used only in connection with private telephone lines phone—for instance, at the desk or sewing-room during the day, in the living-room in the evening, and near the bed at night. The only important point to watch is that the base and sockets are con- nected so that the color of the wires is preserved throughout; for instance, always red to red, and green to green. The accompanying illustration shows the scheme.—V. H. Topp. An Easily Constructed Fountain for the Lawn HIS fountain has a double bowl or basin formed by placing a high- voltage insulator about 18 in. in di- ameter over a \4-in. pipe that is con- nected with the water-line. On the end of the pipe is a coupling having a small nip- ple and over this is attached an automobile- tire dust-cap, which is pierced with many holes about as small as the point of a pin. This cap fits down to the shoulder of the coupling. wi) 3A, {SAKA \ LAX ya) aN AUTOMOBILE TIRE DUST Although made of simple material, this fountain is at- tractive To Prevent Shoes from Losing Their Shape VEN the most expensive shoes soon lose their attractive appear- ance through wrinkles and cracks that form above the heel part as the result of the constant bending and creasing in walking and careless han- dling in the removal of the shoes. The forming of these creases may be prevented to a great extent by placing what may be call- ed an invisible shoe-horn in the heel, as shown in the illustration. This support may be made of thin spring steel or the same kind of leather of which the count- er is made and it will stiffen the back of the shoes sufficiently to prevent creasing. THIN. STEEL The steel preserves the shape of the shoe 82 Popular Science Monthly Homemade Exhaust Fan for the Lathe Y the aid of a desk-fan a device may be constructed for removing by suction the dust and small particles of grit and grindings that otherwise would fill the air around the grinder to the detriment of the workmen oper- ating it. The fan, which is reversed, furnishes the suction and draws the dust and metal powder through a funnel-shaped metal hood. The rubber hose, ending in a scoop, leads from the hood to a point just below the grinder. All dust particles are suckediin through the hose and are drawn toward the fan. They REVERSE FAN RUBBER HOSE —_> scoop aang ELECTRIC GRINDER Like a vacuum cleaner, this device will suck in the dust and grit from the grinder are stopped, however, by a fine screen in front of the fan and can be removed from the screen from time to time by gentle tapping. This device has been used with re- markable success on a machine for grinding typewriter cylinders. But that is no reason why it should not be equally successful in cases where other materials are ground.—N. G. NEAR. Putting Up a Simple Treilis for Runner Beans N the accompanying illustration is a simple trellis that can be made in a shorter time than is usually re- quired for such trellises, and that will be as effective as any. Two posts are set at the ends of the rows, and a wire stretched taut be- tween them at the top and bottom. Cord such as binder twine is then wound around the two wires in such a ype mm y CORD Nw tan as UL POST WIRE POST An easy method of constructing a trellis for training runner beans way that nearly vertical sections result as shown. | If the cord is spaced about a foot apart, it will be found to be as effective as woven wire or especially prepared frames, and at a cost that is trifling. The posts may be simply stakes driven into the ground far enough to withstand the stretch of the wires, and, at the end of the season they may be stored away.—DALE VAN HOorNn.

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i i ilt ot ve ed ces id, July, 1921 Triangle that Gives Vari- Sized Cross Sections. ANY draftsmen have need for a small and compact cross-sec- tioning device. The one illustrated is easily made from two celluloid tri- angles at a saving of expense. A 45° triangle is cut as shown, the length and depth of the recesses de- pending upon a6 y the size of the SS triangle. A smaller triangle of the proper size is then cut as shown in the NO, illustration, the YY Severaldifferent length of the spacingsmay be projections and obtained with — these triangles their respective recesses being determined by the spacing of the lines that it is desired to draw. At least five different spacings can be secured by turning the inner piece. In use, the palm rests on the lower left-hand corner of the large triangle and the forefinger is inserted into the hole of the smaller one. By alternately moving one and holding the other triangle down, even spacing of the ruled lines is thereby secured.— WILLIAM MELAS. Place a Mirror to Throw Light on Your Work VEN in well lighted shops it is sometimes difficult to obtain good light on inside work on a lathe or other machine. Such cases. would fre- quently be helped by ob- : taining the re- LIGHT quired light by reflection. en The picture illustrates the method which was used in one particular case to illu- minate the in- terior of a tube of metal on whichsome interior lathe work had to be done. The mirror was fastened to the tailstock of the lathe with a universal jointed bracket, so as to reflect either the light from a lamp or the rays of the sun into the interior of the work.—JOHN HOMEWOOD. With this mirror light may be thrown on the work where it is most needed A Decorative Flower-Box for a Window UNGALOWS, front porches, and summer cottages may be made very attractive by this window-box. Plan a box about 6 in. deep and the same width as the window. Fillit with plenty of good rich soil. Then plant a few pansy plants, a bunch or so of Shasta daisies, some mignonette, etc. Now take several ordinary baling. wires, which will be about the right length for the purpose, when cut in two parts. Bendthe wire, as shown _BALING WIRE in the illustra- =F tion, in designs == to suit your taste. Use fine wire to fasten ; the wires to- 9 gether. This 4 gives the effect of wrought-iron work and is most attractive, even before the flower run- ners entwine them. Give the wood a coat of gray or green paint and the box is finished.—M. A. OSBERG. Climbing plants make this window- box very attractive A Tinting-Tile Made from Developer Tubes LASS vials, test tubes, and es- pecially developer tubes make ideal tinting-tiles. Any hard wood of the desired length, several inches wide, Using a Clamping-Nut Saves Time UPPOSING it is required to clamp work of varying Jengths upon a screw arbor, much labor can be saved by making the clamping-nut as shown in the accompanying illustration. First tap it as usual, then bore a hole larger _ than tap size through it at an angle. The nut may then be slipped upon the arbor through the bored hole of the nut over the threading until it straight- ens itself against the work, whereupon Architects and artists will find this homemade tinting-rack very useful in their work and an inch thick will serve as a base. Into this a sufficient number of holes are bored, 34 in. deep and a trifle larger than the diameter of the tubes. Both sides of the wood may be grooved to hold brushes, etc. The base colors in corked tubes are placed at various intervals, and the other tubes, half filled with water, are used to hold the tints of the concen- trated colors. A medicine-dropper is a handy medium to transfer the colors.—A. SCHAAL. Have You Tsied to Draw on Glass? O write on a glass surface it is necessary to impart a certain de- gree of roughness to the surface. After repeated trials of various rougheners, a varnish of sugar was found to be the best method of obtaining this roughness. Equal parts of white and brown sugar should be dissolved in water until the solution has a consistency equal to that of athin syrup. Alcohol is added as a drier, and the varnish applied to hot glass plates. 83 CENTERLINE 47~ OF BORE « FIRST TAP BORE HOLE LARGER THAN TAP SIZE AT ANGLE SHOWN Much time and labor may be saved by employing the clamping-nut described and illustrated here the threads will mesh and the nut will hold as well as any other kind. To take off the nut, simply loosen it until the threads may be thrown out of mesh.—R. F. POHLE. To Pour Acid from Carboys without Spilling ERE is a self-explanatory illus- tration of a simple method used by a battery-charging station in south- ern Missouri to empty the large acid carboys in which battery acid is shipped. Distilled water is also re- ceived in similar containers. Before this tipping device was used, several REVERSE SIDE OF Ay TRUNNION = o> Som ~OLOCK OF With simple tools this cradle for tilting carboys can be made from a few strips of lumber carboys were accidentally broken, and there was always a good deal of waste in trying to remove a small amount of acid or water from the carboy. This apparatus was made of soft 1 in. by 4 in. timber, but it could be improved by making the swinging cradle of strap iron, which would give added strength.— VERNON G. Cox.

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aS ET SS ee Oa eae e > aee A Handy Acid Cup Made from an Insulator HERE acid is used in bench;work at the repair-shop, particular care should be taken to provide a container that cannot easily be tipped over or broken. Acids are very de- structive and \ when spilt. on GLASS a bench may if INSULATOR cause gréat \ damage. , An excellent acid cup can be made from an insulator for CONE- SHAPED TIN RIVET electric wires set In a cone- This acid cup is not shaped base easily upset made from a piece of heavy tin, as shown in the illustration. The in- sulator cup is not attacked by the acid and the broad and heavy base gives it stability. Holding the Window at Any Desired Height OST windows have but two stops for the window-bolts, and hence can be raised but two heights. From a strip of strap iron about 1 in. wide and ) in. - thick can be made a stop that will make it possible to raise the window to any desired height. goit CORRUGATED STRIP Such strap iron can be obtained at any shop where galvan- ized sheeting is sold or used. The _ strap iron can be easily bent into corrugations to receive the win- dow-bolt, and- countersunk — holes should be bored at each end to receive the screws for a securing a ae line 7 . The belt engaging The bolt should the strip holds the be fastened to ~~ window the face of the Ae lower window-frame.—W. W. PARKER. Nuts Must Fit in Order to Be of Service Tae users of machinery should always bear in mind that an ill-fitting nuttis practically of no value, and should never be used. A nut with 12 threads to the inch may be placed upon a bolt that has 10 threads to the inch, and, according to the thickness of the nut, may be put on all the way or only part of the way. If it is forced on, the threads of the nut as well as of the bolt will be ruined. The pic- ture illustrates that in a case of this kind only one thread can be in contact and that ae not all the way around, — because of the different pitches. If the nut ONLY PLACE OF USEFUL CONTACT What happens when the nut does not fit . a diameter is so thick that another thread comes in contact, the second contact will be on the opposite side of the thread. It j obvious that the nut that holds merely part of one or two threads offers no seé ity. The thread is easily stripped and the nut slips off. - It should also be remembered that nuts that are too large, even if they have the same thread as the bolt, are objectionable. They hold only by the sharp edges of the threads, which are easily sheared or broken off.—N. G. NEAR: rn Ferrules from Short Lengths of Pipe Spewepd pieces of well-pipe, if driven on the heads of tent-stakes will prevent them from splitting when they are driven into the ground. The pipe should be cut into pieces 2 in. long with a hacksaw. The pipe should be of to correspond with the size of the tent-stakes; 114- in. pipe is large enough for small stakes, while larger ones re- quire a pipe of 2 in. in diam- eter. The heads of the tent stakes should be trim- med to fit the pipe and should have a shoulder about 2 in. from the top of the stake. As the wood may shrink, it is advisable to drill a hole through the stake head and the ferrule, insert a nail, and rivet it at both ends, to prevent the ferrule from slipping off. im | SHOULDER Tent-stakes should be protected by ferrules Build a Boat Driven by an Air Propeller [ITTLE boats driven by air propellers may be put together in a few minutes. The hull should be of soft light wood, preferably white pine, and it must be cut in the manner shown. It should be ‘carefully sandpapered and shellacked so that it will offer little resistance to the water. The rubber band is held by a hook made of strong wire at one end, and the bearing for the propeller is also made of a strong so that he may pull it back after the propeller has stopped piece of wire. These wire supports should be placed in the block so that the balance will not be destroyed. They must be mounted exactly the same distance from each side. The propeller used is of the type employed on model airplanes. 84 oe et a? > not be thrown away. Popular Science Monthly Domestic Usefulness of an Old Auto Switch LD automobile switches that have out- - lived their usefulness in the car should If your house is wired for electric light, some .of. these switches may be © used to advantage for controlling the electric - light connections in various parts of the house. There are many other uses that will suggest themselves to the amateur home _ electri- cian. The switch may also be used on an elec- tric toaster, per- colator, or an electric iron. An electric switch has many uses Ice Bills Reduced by a Submerged Cooler T a local ball park drinking-water was supplied from a tap from a city main, but it was always too warm to be palatable because the pipe-line was laid too near the DRAIN TO SEWER: This shows how the water in public drinking-fountains may be cooled dur- ing the hét.#eason at a small expense i ; surface of the ground. The water had to be iced before it could be used. : The system. illustrated here was? finally hit upon and gave satisfaction. It saved 50 per cent of the previous ice bills. A Saddler’s Needle as an > Engraving-Tool AVING consented to cut a friend’s initials on the handles of his um- brellas, I found that I had no engraving- tool. Pressing a saddler’s or bayonet needle into service, I improvised an en- graving-too! as illustrated here. I drove the eye end of the needle into the short wooden handle, then cut off the point of the needle and ground it as shown at B. Fig | The first cut A - should be made with a twisting motion, leaving a zigzag mark as shown in C. The cuts are later smoothed out.—J. M. KANE. Fig.2. , How a= saddler’s needle became an engraving-tool Za ee | LS: Sa

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July, 1921 BEST RETAIL TRADE Frode Mark Reg US Pot Of and Foren Countries It is your Guarantee of No Underwear is “B. V. D.” without This Red Woven Label wee Value and Satisfaction ft .¥ neem: acannon iam sacenaaattinn = ves ae as E ‘6 ” ; sa B.V. D.” Underwear developed an entirely new principle which completely revolutionized summer underwear. The foundations of the world-wide popularity of “‘B. V. D.” Underwear are value and satisfaction. The “B.V. D.” ideal of service is expressed in the durable fabric, made in our cotton mills, and in every successive stage of manu- facture—the result: proper-fitting, comfort-giving, long-wearing Underwear—‘‘B.V. D.” ~ “B. V. D.” Sleeveless Closed Crotch Union Suits (Pat. U. S. A.j Men’s $1.50 the suit, Youth’s $1.15 the suit. THE B. V. D. COMPANY NEW YORK Quality Ever Maintained “B.V. D.” Coat Cut Under- shirts and Knee Length Drawers, goc the garment. TIaly. 1921 THEB.V D. CO.

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AERTS LE SA I AES OT TE EFT SLOT ET TT LIES TSS ETT TTA TITEL ETS A 9 7 SBE PP ONS Tn ER Wear Rubber Cuffs in Handling Meat OUSEKEEPERS, butchers, or trades- men handling goods that are liable to soil their linen and clothing will find it practical to wear protecting cuffs. A small section of an inner tube may be used as Anybody that has to do messy work may protect his shirt sleeves by wear- ing cuffs made from an old inner tube shown in the illustration. If desired, a longer piece may be employed to form an oversleeve reaching to the elbow or beyond. These rubber cuffs can be kept clean by washing them from time to time with soap and water.—C. A. BLACK, JR. An Old-Time Brace and Its Construction pee among the interesting relics of Revolutionary days resurrected from the trash-pile in the attic of an old building was a brace that had evidently been made by a black- smith for use in his own shop. Its form and construction are clearly shown in the illustration. Of particular interest is the ingenious method by which the maker solved the problem of providing the brace with a swiveling hand- rest. The illus- tration needs no further explanation. The shank of the drill or auger is fitted into a square hole of the tool arm of the brace. qa Observe the clever construction of the handrest How to Make a Bow-Gun without a Bow HE bow-gun without a bow described here will shoot arrows a considerable distance. It is easily constructed and re- quires only materials found about any home work-bench. First to be made is the gun-stock. This is whittled or sawed out of a piece of soft, straight-grained wood 36 in. long and about 1 in. thick. The barrel should be left about 4 in. wide and a 1-in. slot, parallel to the edges, should then be cut through the center and for nearly the entire length of the barrel. Leave 3 or 4 in. of solid wood at the end. Groove the top edge with a gouge. - The carrier, or that part which propels the arrow, is illustrated in detail. This consists of two square pieces of wood about 4 in. each way. Each should have a rib, intended to travel in the gun-groove. A third piece of wood is screwed across the tops of the two sides. Insert a screw-eye in the front edge of each side piece of the carrier. On their under side the side pieces of the carrier should be connected with a U-shaped piece of stiff wire. The carrier should slide back and forth easily upon the barrel without coming off. Next, insert a screw-eye on each side of the barrel at the end and connect these with the screw-eyes on the carrier by stiff springs from curtain-rollers. The shorter these springs are, the farther they will force the arrow. The trigger, shown in detail, is made from a common strap hinge of suitable size. Curve one end to form the finger-hold. The other, long end, should be bent to form at its end. Slots on each side of the hinge = 36" | sTOP> SLOT s y SPRINGS TRIGGER FLAT SPRING —_ HOLE FOR STAPLE : a, STRAP HINGE TRIGGER DETAIL A a RI CARRIER DETAILS TRIGGER WIRE FEATHER-——&_ LM, ine LEAD Narrow | = a 24 ——' The distance to which the weighted arrow can be shot depends on the strength of the spring will allow a staple to hold the hinge on the under side of the gun-stock. Make the arrows about 2 ft. long, round- ing and smoothing them well so they will slide easily in the groove. Wind lead around one end and tie a feather at the other. The best balance will have to be determined by experiment. The gun is operated by pulling back on the carrier until the latch hooks behind the trigger. Insert the arrow in front of the carrier, put the gun to the shoulder and pull the trigger. This releases the carrier, which shoots forward by the pull of the springs, and drives the arrow to the desired target.—L. B. ROBBINS. - A Cabbage-Cutter Made from a Spade A VERY useful cabbage-cutter can be made from an old spade. In the first place, a wedge-shaped portion is cut from The sharp edges of the V sever the cabbage from its stalk the spade, as is shown in the picture. - The edges of this are then sharpened with a file. In using the cutter, the open part is pressed against the stump of the cabbage. When this is cut through, the cabbage falls on the spade and can then be tossed into a cart.—S. LEONARD BASTIN. 86 Popular Science Monthly Real Butterflies Beautify the Serving-Tray is very easy to make an ornamental glass-covered serving-tray. The only requirements are an ordinary plain glass- covered serving-board, some absorbent cotton, some dried grasses or silk from milkweed pods, and a few butterflies. When the butterflies are caught, they are placed in the fumes of ether or any Arranging the material that goes into the making of the decorative tray other medium that quickly kills them. As soon as possible after they have been caught they should be spread on the spreading-board so that all parts lie sym- metrically. Here they remain for one or two weeks until they are perfectly dry. When the butterflies are ready for use, take the tray, remove the back and place the cardboard backing upon the table. On this cardboard spread out a thick layer of absorbent cotton as evenly as possible and cover the cotton with a piece of silk. On this silk place a few grasses or milkweed seeds arranged artistically. Then take the butterflies from the spreading-board, care- fully remove the pins, and lay them or the silk as desired. When this has been accomplished to the satisfaction of the worker, take the glass The completed glass-covered tray is not only useful but very ornamental and carefully and gently lower it upon the butterfly-covered silk. Lift up the entire - design and place it in the frame. Gently but firmly press it down so that the back fits snugly into the grooves of the frame, and nail in place. For greater strength it is advisable to back up the cardboard with a thin piece of wood covering the entire frame.—E. BADE. To Lubricate Fine Watches and Chronometers Oo” suitable for lubricating the bearings of fine watches and chronometers has heretofore been obtained almost exclu- sively from the maxillary fat of the por- poise. The cost of this lubricant is about $250 a gallon, which is almost prohibitive, notwithstanding the fact that only minute quantities of the oil are used. Recently a thoroughly satisfactory oil for this purpose has been obtained from petroleum by a new process and its cost is insignificant compared with that of the porpoise oil. a) eee a on ah

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July, 1921 A Multiple-Cup-Boiler Solar Engine HE illustration below shows a boiler for generating steam enough toruna small turbine. A number of semicircular partitions or bulkheads are placed along the bottom, dividing it into a number of compartments or cups. With these, the boiler may be tipped at a considerable angle, yet expose a maximum amount of water to the heat. In building the boiler, a cylinder of sheet metal is cut in two, and ends and bulk- heads fitted into one half, then the second half is soldered to this. The boiler is put into a long glass jar hung from a metal rod ( = REFLECTOR FIG.4. This apparatus demonstrates the heat-pro- ducing powers of the rays of the sun and over a parabolic reflector. The illus- tration gives a suggested design for the toy turbine to be run by this boiler. After a run, the water remaining in the boiler should be poured out. It may then be refilled with the exact required quan- tity.—EDWARD R. SMITH. How Rope-Twisting Is Done in India OPE-TWISTING is one of the industries of India, where jute is grown for that purpose on a large scale. Little modern machinery is used in this industry, but the results are quite satisfactory. The illustration shows the ingenious apparatus employed for giving the rope a EVOLVING PINDLE Alternately pulling the two ends of the rope coiled around the spindle gives a continuous rotating motion to it continuous twisting motion by alternately pulling the two ends of the rope coiled around the twisting spindle. It is a curious application of well known mechanical principles. They Have Found A better way to clean teeth Dental science has found a_ better way to clean teeth. Modern authorities approve it. Leading dentists every- where advise it. Millions of people already employ it. A ten-day test is offered to anyone who asks. Get it and see the delight- ful effects. Learn what this new way means. Combats the film You feel on your teeth a viscous film. It clings to teeth, gets between the teeth and stays. The tooth brush, used in old ways, does not end it. So nearly everyone has suffered from some film attack. Film absorbs stains, making the teeth look dingy. It 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 pyor- rhea. Thus most tooth troubles are now traced to film. New-day methods After diligent research, methods have been found to fight film. Careful tests have amply proved them. Now they are being very widely adopted, largely by dental advice. PAT OFF... Pepsodéen REG.U.S. The New-Day Dentifrice A scientific film combatant, whose every application brings five desired effects. Approved by highest authorities, and now advised by leading dentists everywhere. All druggists supply the large tubes. NIA SEE LIOR ELITES ITN DIE 87 The methods are embodied in a den- tifrice called Pepsodent. They can thus be twice daily applied. And to millions they are bringing a new dental era. Important effects Pepsodent combats the film in twe effective ways. It also aids Nature in three ways which faulty diet makes essential. It stimulates the salivary flow—Na- ture’s great tooth-protecting agent. It multiplies the starch digestant in the saliva, to digest starch deposits that cling. It multiplies the alkalinity of the saliva, to neutralize the acids which cause tooth decay. . These things should be daily done for better tooth protection. See the benefits Send the coupon for a 10-Day Tube. Note how clean the teeth feel after using. Mark the absence of the viscous film. See how teeth whiten as the film- coats disappear. Watch the other good effects. Judge then by what you see and feel and know. Decide if the people in your home should brush teeth in this way. Cut out coupon now. 10-Day Tube Free “* THE PEPSODENT COMPANY Dept. 786, 1104S. Wabash Ave., Chicago, Ili. Mail 10-Day Tube of Pepsodent to | eee ee ee ee ee ee ee 2 Only one tube to a family

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(Se aE ARQ RMSE ST — RINE KP RTE BIAS KES RET SSR Se PRN a ea a SE a ee eee PTET CS eke > * ree FRE RETR 2 Sai - LS Oe LD A eee ee Seas he BRS “one ne epee oe ee eS y ey oF *50.a week ce) (overs dulce Mechanically Inclined Good Pay for You in Auto Business Hundreds of good jobs paying around $50 a week are open for Swee- ney trained men. Garages, repair shops, welding or vulcanizing shops, automobile agen- cies, etc., have written to the E.J.SWEENEY | Sweeney School PRESIDENT asking for compe- Se 2S aN SAE Tae ean ae tent mechanics. The Sweeney School at Kansas City is the world’s largest and most famous auto and tractor school. It trains men in eight weeks by the Sweeney System of Practical Experience. This system under Mr. Sweeney’s direction turned out over 5,000 army mechanics during the war. Many thousands of Sweeney trained men hold responsible and profit- able positions in the automobile business. An interesting feature of this training is that no previous experience is required. No books are used and everything is taught by working with your own hands. It is so simple that a deaf and dumb man learned to be a good mechanic in eight weeks. The Sweeney School publishes a great number of applications from garages, repair shops, etc., asking for men. ‘“‘I want a head mechanic and will pay $50 a week’’ writes one concern. ‘‘Want two mechanics. Pay 60 cents an hour. Please wire,’’ writes another, LEARN IN 8 WEEKS tut SWEENEY SYSTEM Mr. Sweeney publishes a - beautifully illus- trated 72-page catalog that tells all about opportunities right now in the auto and tractor business. He will send this free without any obligation, together with the Sweeney News, an interesting paper and full information about the demand for trained men. This literature plainly shows how any young man mechanically inclined who is willing to work hard for a few weeks can fit himself not only for a job, but for real success in life as owner of his own business. There are many opportunities in both city and rural districts. Simply send name today for free catalog to E. J. SWEENEY, President, Sweeney School, Auto, Tractor and Aviation, Dept. 878, Kansas City, Mo. MAIL THE For Big Free Catalog Mail This Coupon EMORY J. SWEENEY, President Dept. 878, Sweeney Building, Kansas City, Mo. Please send me free without any obligation on my part your 72-page catalog and your Sweeney School News. Tell me of the opportunities in the Auto and Tractor Business. ee ee ee Paddle Your By E. STRONG, serviceable, inexpensive canoe can be easily built by any one who is handy with his tools. The first mat- ter to be decided is the length de- sired. This will depend entirely upon the number of persons the The graceful lines of the canoe is to carry. ©@noe are shown here For two persons a 12-ft. boat is sufficient. The determined length of the finished craft is laid out in the keelson, which should consist of a 34 by 134 in. piece of cypress. To this are attached the bow and stern pieces, which are sawed out of a cypress board 4 in. in thickness. These pieces should be uni- formly curved and are attached to the keelson with brass screws as soon as cut. Two bulkheads are then cut out and attached to the end of the keel and to the bow and stern pieces. Then the center rib or crosspiece is made from three pieces of wood mortised together. This is also screwed to the keelson in the exact center of the boat. Two more ribs must be made in a similar manner and attached halfway between bulkhead and center rib. Now the rib-bands or strips to which the canvas is attached, are placed in water and saturated for one or two days so that Putting in the rib-bands; the last oper- ation before the canvas covering is put in its place Popular Science Monthly Own Canoe Bade they become soft. These consist of 14 in. by 1 to 114 in. pieces, about 14 to 15 ft. long for a 12-foot canoe; for a larger canoe longer pieces must of course be used. When these pieces have become soft and can be bent easily, they are attached to the stern piece, bent to the bulkhead, then around the ribs, and to the bow piece. Care must be taken while bending and attaching the pieces with screws that the edges do not split off. After the strips have been attached (eight will be needed), the overlapping ends are cut off flush with the bow and stern. Now the canoe is ready for the canvas. This should be in one piece. Tack the center of the canvas to the keelson, stretch it firmly over the center ribs, and tack it in place with copper tacks. Con- The wet canvas should be tightly stretch- ed over the ribs of the canoe before it is tacked down with copper tacks tinue to tack the canvas in place along the ribs and the gunwale and stretch it as tightly as possible in all directions. If the canvas is heavy and difficult to stretch, wetting will limber it up. All wrinkles must be removed, and the canvas should fit tightly over every part of the frame. When the canvas is in place, a keel piece is placed upon the keelson on the outer part of the canvas. This is a piece of 34 by 1%% in., and it is screwed directly to the keelson through the canvas. It must run the entire length of the boat. When the canvas is dry, apply a coat of white lead rich in oil. The second coat con- sists of a thicker mixture, while the final coat should be quite heavy, but still run freely off the brush. How to Aline Shafting Pulleys HEN a belt connection is to be made from a pulley on a main shaft to a pulley on a countershaft, great care must be taken that the pulleys are in perfect alinement, or other- wise the belt will not remain on the pul- leys. A ‘simple yet square that is at right angle with the shaft. If the two shafts are parallel, the angle between the wire and the countershaft should always be aright angle. This could be ascertained by the use of try-squares. If | the angle is not a right angle, the posi- highly effective method of obtaining accurate alinement is shown in the accom- panying illustration. PULLEYS A large try-square is placed against the main shaft and a MAIN SHAFT ieee tion of the counter- shaft should be changed to make it parallel to the main shaft. The pulleys are placed on the two shafts to coincide PTT See - == with the position of - i string or wire is tied to. the shaft and stretched to the other shaft so that it will This illustrates the be in perfect contact pulleys on parallel with the arm of the square and wire 88 the wire. me ie os This method is much more direct and method of alining simple than methods shaftings by try- requiring complicated measurements. es Fe Oe — le One, Ser en

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t we me DO ee or OD 6 mOoonrwct Od tf an en July, 1921 —— July. 1921 How to Make Your Own Section Liner r you do not possess a section-liner in- strument of the rather expensive kind, a perfectly practical one may be quickly im- provised for use in connection with a This section liner costs nothing and is as serviceable as an expensive one draftsman’s angle (either 30 degrees or 45 degrees) as follows: From thick cardboard cut an angular piece the exact shape of the central opening of the ‘‘angle”’ to be used, then cut from one of the edges at right angles to the T-square a strip equal in thickness to the spacing desired between the section lines. In using the device, hold it as shown in the accompanying drawing and move both the device and the angle along the T-square alternately in the same manner as with all section liners.—EVERETT ROGERS. A Jig for Accurately Slotting Valve-Stems O facilitate the accurate slotting of engine valve-stems, the' jig illustrated here was employed in a repair-shop. The jig consisted essentially of a bar of cast iron, in the form of a square prism. Three holes A were drilled along its length, the diameter and depth of the holes being Kla> % ORILL—a! ve fap \ a With this jig valve-stems may be cut with accuracy | determined by the dimensions of the valve- stem. In addition, five %-in. holes were drilled vertically, their centers being lo- cated as indicated in the illustration. Operation of the jig was as follows: Place the valve in the first hole, and drill first vertical hole. Remove the valve and Place it in the second hole, insert a pin to line up with the hole previously drilled, and drill the second hole. Repeat the opera- tion, remove the valve, and with a round file, cut through the three holes drilled. places far apart are brought together, to the t convenience and advantage of the Public and to the certain destruction, in time, of a host of pett jealousies, blindnesses and prejudices, by which the Public alone eal always ae eee sufferers. From Charles Dickens’ Preface to Pickwick Papers. The Advance _ of Understanding Even romance of sixty brief years ago could not imagine the great advance heralded by the passing of the stage coach. The railway and telegraph were coming into their own; but the telephone had not been so much as dreamed about. standing; and to eliminate the “host of petty jealousies, blind- nesses and prejudices, by which the Public alone have always been the sufferers.” Then came the telephone. And with its coming time and distance are swept away and a hundred million people are mad> neighbors. Yet the wise men of that day saw the imperative need. They saw the value of every step which brought people into closer communication with each other. . They knew this to be the one way to increase under- Places far apart are brought together by 34,000,000 con- versations a day over the Bell System. “BELL SYSTEM” AMERICAN TELEPHONE AND TELEGRAPH COMPANY AND ASSOCIATED COMPANIES One Policy, One System, Universal Service, and all directed toward Better Service SAVE 25% to 60% RAISE RABBITS e GRAFLEX-KODAKS and GUINEA PIGS FOR US °9 Cameras and Lenses of eve Gesctiption. ; new. Save mone Ww now for Large genie. —¥ uickly. We sup- Equal to new. Save y. Write now ly stock and buy alt you raise. Our ATH lies Free Bargain Book and Catalog ; | @ illustrated book ‘Common Sense Rab- wr listing hundreds of agp. prnsablge fe bargains in slight. bit and Guinea Pig Raising,’’ Contract ly used a new supplies. and Prospectus lic, teils you how. Quarter! lee oe) goods sold on 10 ¢ ays Free Trial. "a, I , 20¢ Both > Rook if not satisfied. ake no chances a 9 1 25e. — cde deali: ith ETc Weailhave boss bas (h phot graphic business over 18 years. now. OUTDOOR ENTERPRISE CO. CENTRAL CAMERA CO., Dept. 67, 124 S. Wabash Ave.. Chicego __ SED Live Stock Dept. 508, Kansas City, Mo. LAUNDRY SUPERINTENDENCE AND MANAGEMENT There are 10,000 Laundries in this country. Properly qualified Superintend- ents and Managers are needed. The Power Laundry Cooperative Course trains men in two years, half time spent in actual laundry work for wages. Other Intensive Two Year Day Courses INDUSTRIAL MECHANICAL ENGINEERING INDUSTRIAL ELECTRICAL ENGINEERING ARCHITECTURE INDUSTRIAL ART For ostehin announcement write the OHIO MECHANICS INSTITUTE Dept. B Cincinnati, O. 89

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PS EIA OL PE DOLE RT ONION A IT NP ae a ag ere ey SS ERR RRR. ee IIR poe RR RSI A * ARR R o = pee —— - SE eee ee PATENTED U.S.A. FOREIGN PATENTS PENDING & Very LIGHT ano VERY sTRONS Do You Own a Car? DELUXE light weight, cast iron pistons will increase the power, speed and flexibility of any motor and at the same time use less gasoline and oil. They also reduce repair bills by eliminating vibration. Thousands of motorists in every part of the world are proving this every day. DELUXE PISTONS ARE 40 TO 50% LIGHTER THAN STOCK FACTORY CAST IRON PISTONS The weight is saved and strength gained by their patented scientific reinforced construction. Note the rein- forcing ribs under the head and down the skirt. These reinfgrcements give the piston much greater strength. The reinforcing ribs also serve to carry off heat, insuring a cooler running motor. The DELUXE piston has much less expansion than either aluminum or heavy cast iron pistons. They can be fitted close. Write for booklet giving full information. Supplied standard or over-size for more than 800 makes of automobiles, trucks, tractors, airplanes, motorcycles and marine engines. Patented and Manufactured by CLARK-TURNER PISTON CO. Station C Los Angeles, Calif. For Sale by All Good Dealers and Repair Men. “Success in Music How To Win It” L=t Sousa, Pryor and eight other world-famous musi- cians tell you secrets of their success; how to discover and cultivete your musical ‘ ‘bump”’; double your income and pleasure playing in band or orchestra. FREE TRIAL Any Instrument Conn instruments are used by - world-famous artists. Known every- ig, where as easiest of all to play. Try any instrument o obligation; easy payments when you buy. Send coupon for free book and details of free trial plan. iD) eee Ge Mm ==) =) E| CS = 732 Conn Bldg. Elkhart, Ind. Agencies in alll large cities ‘we Lg 8 8 F FF C. G. Conn, Led. 732 Conn Bidg., Elkhart, Indiana. Gentlemen:—Please send: me ‘‘Success in Music” and details of your free trial plan. (Mention instrument.) Name Street or Rural Route—_ City, Counry—__ State Instrument ——_ Standard Underwoods 5-Year Guarantee Yes, this “ogame Standard Visible Writ- ing Un + we new ~ * S$ ie) rebuilt, at , yours fam Paty 3. 60down and then easy monthly payments, s FREE T. . days at viel s at o \. Send now for 10 Da Boney ack for ee Dargain gS 0.2145 48 yt TyPEW! Pomun gs Shipman Building pe Popular Science Monthly A Compressed-Air Engine of Cigar-Box Wood | iene flywheel for this compressed-air engine should be made from two disks of cigar-box wood 5 in. in diameter, nailed together with the grain of the wood at right angles. The crank-wheel is made like- wise, but is only 2 in. in diameter. Both wheels are held on a wire shaft 4 in. long. A piece of a steel knitting- was a hand type °4 in. in diameter and 5 in. long. The upper end of the piston- rod was drilled to take a small nail that makes its bearing upon the crank-wheel as shown. The valve, which allows the air to enter and leave thecylinder at just the right time, is a plunger on a small needle makes a good shaft. The base is the end of a cigar box, being 5 by 2 in., and the two upright supports are the sides of the box, be- ing 8 by 2 in. One side has to be removed from its original position and nailed in place halfway along the end. A brace 21!%4 by 2 in. is nailed across the top of the two supports. The bicycle pump that is used for the cylinder has a 1;-in. brass pipe soldered to its lower end with a hole drilled through its side to wire that works back and forth in the valve-pipe. The piston is made by winding cotton thread upon the wire until it just fits inside the pipe. The valve wire is 3 in. long and is pivoted to the lower corner of the valve- rocker triangle. This triangle is 2 in. along the horizontal and 2)4 in. along the vertical side. It is pivoted at the corner to a support. A rod connects the outer corner of the triangle with an eccentric pin on the flywheel. It will be readily seen how fit over the hole in the base of the pump. This valve-pipe is 4 in. long. The cylinder rocks back and forth as the crank-wheel turns on its valve- pipe as a pivot, and the manner in which the pipe is held by its two supports is clearly shown. The valve-pipe should be 15 in. from the base. The pump used Boys can learn a great deal from this primitive model the engine runs by com- pressed air forced into the pipe at the base cf the cylin- der. The valve is carefully adjusted so that just as the piston starts up, the plunger allows air to enter the cylinder and also cuts off the air just as the piston starts on its downward stroke.—F. E. BRIMMER. How to Etch Your Name on Tools ECHANICS should learn how to etch their names on tools. outfit is shown in the illustration. prises a bottle of nitric acid, some asphalt varnish, a medicine dropper, a stylus, a piece of chalk, and a small water-color brush. A little paraffin will also be necessary. The stylus is made of a small piece of doweling with an old phonograph needle in oneend. A small hole slightly smaller than the phonographic needle should first be drilled in the doweling so that the needle can be inserted without injuring its point. Another sty- lus is made with a flat point. This point is made of a small rod filed off flat at one end. When nickel is to be etched, a mixture of equal parts of sul- phuriec and nitric ASPHALT VARNISH acid should be used. Such a solution is known as aqua regia. First clean the surface of the metal to be etched, and be sure that it is free from all traces of grease. Now paint over it a thin film of asphalt varnish. Permit this to dry until it is just beyond the tacky stage. Now grind up a little chalk and mix it with the water. Paint this over the black surface with the paint-brush. Allow this to dry. The black surface will be made ‘white and pencil marks can be made upon it. The design, initials, or name to be etched upon the tool is now sketched out with a pencil. When this is done, the stylus is used to scratch the varnish be- neath the pencil marks, exposing the bright metal. Now build up a little wall of paraf- fin around the initials. With a medicine dropper suck up a little acid and drop it 90 A little etching It com- into the letters, forming a little pool. The acid will immediately attack the metal, causing bubbles to rise. When the bubbles cease to rise, suck the acid off with the dropper and replace it with fresh acid. It will be necessary to do this several times before the acid will have a chance to etch a deep letter. When the worker is satisfied that the letter is etched deep enough, he should wash the tool under the faucet. The asphalt varnish is then scraped off and the tool cleansed with an oily rag to prevent rust. It should be said here that the sulphuric acid will work more rapidly if it is diluted with water. Hydrochloric acid may also be Careful mechanics will mark their tools. This describes a method of etching used very effec- tively. This method of etching can be ap- plied for other pur- poses. For instance, if the worker has a disk to cut out of hard-tempered stock, he can apply the asphalt varnish, scratch a circle with a set of dividers, and pour the acid in as before. If the supply of acid is replenished several times, the disk will eventually be eaten out.—CARL ROYER. FLAT STYLUS Imitating Hard Woods Is Not Very Difficult 1* is worth knowing that soft woods, treated with oil stain finished over with two coats of varnish or varnish and wax, can be made to resemble closely light or dark oak, cherry, mahogany, walnut, or mission oak. The work does not require any exceptional skill and the: - result is invariably well worth the effort.

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‘y wr Ve Cre wa 3 mam OD ( oF ( CO he iY Coa mS LP i} er id ly y> es he: . July, 1921 Cooling Drinking-Water on the Farm Wo = coming of warm weather, the proper cooling of drinking-water on farms and in localities where the water supply is held in elevated tanks, becomes an interesting one. After a few hours under the heat of the sun this water becomes tepid and often unpalatable, even after running through underground pipes. But if you possess an old discarded well, or cistern, the problem loses much of its terrors. At a depth of about 20 ft. water in a well retains a temperature of about 45 to 50 degrees, and with greater depth the temperature be- comes lower. So, by running the supply of water from the tank into a well of suffi- cient depth, and leaving it there long enough, it will be cooled to the same tem- perature. Make up a coil of pipe of the same size as that used in the supply line for the house. This coil should be as long as possible, to give a large cooling surface, but should also be constructed with an eye to letting it down the well without difficulty. Each layer of the coil is in the shape of a square and is composed of four equal lengths of pipe and four elbows. Thread them tightly together, using white lead at all of the joints. The last elbow of each section should be inclined just a trifle so that the first pipe ~-SUPPLY FROM TANK PLAN OF COIL The cold water in the well chills the warm drinking-water from the ele- vated tank before it reaches the house of the next section below can be set in place without bending. At the end of the top section and the end of the lowest section arrange two elbows with their openings pointing upward into which are threaded two pipes of equal length. These pipes must be long enough so that when the coil is lowered to the bottom of the well the tops of the pipes can be con- nected with the supply and outlets a reasonable distance underground. Polished Table-Tops Ought to Be Protected NOTHING will ruin a polished table-top more quickly than placing hot plates and dishes on it without adequate pro- tection by a heat-insulating mat. If you have a table with a highly polished top, it will be wise not to depend on individual mats, but to provide a water- proof and heatproof pad large enough to cover the whole table. These pads placed under the table-cloth protect the polish from injury and mean a considerable Saving. KITCHEN q+ TOGAN COTTAGES and SUMMER HOMES For the lake, mountains, or shore. Write us for catalog “Away from City Cares.” It tells you how Togan Cottages come completely built. TOGAN - STILES 1624 Eastern Ave. Grand Rapids, Michigan Keristered 4 } Trade Mark "Iz . MUSICAL ENSTRUMENT MAKING 4 200 YEARS OF NY instrument sent with compete Andee outfit, for a week’s free trial at home. No obligation, Return it at our expense after trial if you wish. Outfit includes velvet lined case, self instructor, music and all accessories at factory cost. A tremendous saving. Monthly Payments A few cents a tiny | will pay. 2 hogy = instruments nown all over the world for artistic quality. Every in- strument known, ay pianos Victrolas included in this Send for Catalog All instruments illustrated with price, easy terms and free trial blank. Catalog free. No obligation. Send coupon now, 117 Eas Street, Cincinnati, Ohio The Rudolph Wurlitzer Co. 338: 3298 Wabash Av. ’Chicagort20W- “toase. NewYork Send me your new catalog illustrated in color with details of Warlitzer Complete Outfits, free trial and easy payment offer.

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A SAT RA Gp TI rene, PRES = ey — are aS A ITE TI LEN BIG Sendo GET A HOBBY MAKE MODELS Start a Home Workshop “Model Making,’ by R. F. Yates, de- scribes the construction of gas-model engines, steam-engines, iocomotives, boats, dynamos, turbines, railroads, guns, etc. Thirty chap- ters are devoted to models of various nature. It will help you to become a better me- chanic. It will help you to do hard soldering, soft soldering, lathe work, tempering, drilling, pattern-making, etc. This isa book every amateur or professional mechanic and model maker should have. . ‘Model Making’ describes real engi- neering models, not toys. 400 Pages, 300 Illustrations. Practical, complete, easily understood. Price, Post- paid, $3.00. Popular Science Monthly 225 West 39th Street, New York — 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 To Keep Dust Out of the Air-Compressor HEN the efficiency of his air-com- pressor began to decrease after having been in use for two years, the owner of a gasoline and air station examined the compressor and found the pipes and tank. filled with dust. As this dust had obviously been taken in through the intake valve, the proprietor decided to put in an air-filter. To the intake valve of the compressor he fastened a 3-in. nipple of 1-in. pipe, on the end of which was an elbow. Fastened to the elbow was a 214-in. pipe-cap, drilled and threaded so as to screw on to the come! a ELBOW INTAKE VALVE = oS NIPPLE | PIPE CAP. ee WIRE MESH | MACHINE SCREWS 22 PIPE 5" LONG CURLED HAIR —+ WIRE MESH MACHINE SCREWS] Filtering the air at the intake of the air-compressor will preserve the effi- ciency of the machine for a long time elbow. Into this cap he screwed a 5-in. length of 214-in. pipe. This pipe had been drilled and threaded to take ten 6/32-in. machine screws, each about !4 in. long. These machine screws were placed five in a circle around the circumference about 14 in. from each end. Disks of fine wire mesh were cut to fit snugly the inside of the pipe and were held in the pipe by the pro- truding machine screws. Between these disks was placed a quantity of curled hair. New hair should be substituted about once every sixty days.—THERON P. Foote. Using a Suction Syringe for Oil RUN my motorcycle at no cost to me for lubricating oil, simply by using what other people throw away. In almost every case, there remains a quantity of oil in tin oil-cans, even after the most careful straining. By unscrewing my motor-horn bulb and attach- | ing to it a length Wy of engine gage- glass tubing, I recover the re- maining oil just as easily as does a syringe take “> up the ink in fountain-pen fill- ing. Any one can make such a suction syringe in a few min- utes.— GEORGE H. HOLDEN. RUBBER BULB oi Enough oil is left in emptied Oil-cans to lubricate a motor- cycle 92 Popular Science Monthly Operate a Used Car Business! Make from $50.00 to $500.00 on Every Deal The Used Car Business offers UNLIMITED POSSIBILITIES for ambitious men, and is a field that is not crowded. If you can drive a car you are fully qualified to enter this most profitable and fascinating vocation. I will send you my complete pr:nted instructions, ‘‘How To Operate A Used Car Business,”” upon receipt of $3.00. By using my instructions you operate without investing any canital. Benefit by my five years’ experience and BE YOUR OWN BOSS. Send Today. PERRY J. SPENCER 116 Atlas Street, Akron, Ohio Why Be a Wall Flower ? Now youcan learn dancing, in your own home, by mail from the greatest dancing instructors in the country. No longer need you stay at home or sit idly by at parties and dances. Join the fun. TRIAL 2 5 LESSON Cc Learn dancing at home with Mov- ing Pictures. Moving Picture Machine free. Instructions and diagrams teach you every step. Just follow the pictures. Any- one can learn. Teach the children. Waltz, Two Step, Fox Trot, One Step and the new College Rock. Address ARTHUR MURRAY SYSTEM OF DANCING Dept. 47, 290 Broadway, New York m PERFECT HEARING! THERAPHONE Ear-Tuned Ear- pieces insure perfect hearing with- out effort. Powerful and Distinct. Ideal for noisy places, deaf, busy and nervous people. Save time and energy, Efficient and practical. Affixed in a minute. Endorsed by men of affairs. Check or C. O. D Satisfaction guaranteed. State make of phone. (Specialty Salesmen Wanted) THE EVOLUTION PHONE COMPANY, Inc. 2a 48-NE Greenwich Ave. New York City Print Your Own cards, circulars, labels, tags, menus book, paper. Press $12. Larger $35. Job Press $150 up. CUTS EX PENSEIN HALF. SMALL OUTLAY. Pays for itself in short time. Will last for years. Easy to use, printed rules sent. Print for others, BIG PROFIT. Write factory TODAY for press catalog, TYPE, cards, paper,envelopes, THE PRESS CO., 0-33, Meriden,Conn. $3 Now! (\ = N= 6 3 ES fe): Motorcycle Bargains SAVE 25% to 65% on Slightly used and Rebuilt Motor- cycles, Side Cars, Johnson Motor & Wheels, Evans Power Cycles, Bicycles. Send for Free Bargain Bulletin and «3 Money Saving Message, listing hun- dreds of Bargains in used. rebuilt and new machines,su pplies, accessories, etc. AMERICAN MOTOR CYCLE CO. Dept. 702, 2047 W. Chicago Ave., CHICAGO IN POP-CORN CRISPETTES Meisner, $250 in one day. Shook, $311 one day Sept. 1920. “eee, Erwins boy (going to school) > makes $35 every Sat afternoon. — eave $6 wilde $25. . xk! io theory o guesswork! Actual proven record of successes. Send for booklet, Long Eakins Co., 747 High St., Springfield, Ohio LEARN AUTOS AND TRACTORS Wonderful opportunities constant- » ly offered trained men; we train ae thoroughly to start your own usiness or make good money as motor expert, driver, shop fore- man. etc. 5000 graduates making good. NI Ws ‘ Catalog Free. A ~ . Cleveland Automobile School, \ > d | Sa A “MMM 1821E. 24th St., Cleveland, Ohio. Secure a Motor-Cycle at a Low Price by putting a Reliable Steffey Motor on your wheel. Easy to attach. Costs less to run than an expensivé mo- tor-cycle. If you write at once you can secure one at the low factory price. Send stamp. STEFFEY MFG. CO., Dept. S, 5025 Brown St., Phila., Pa.

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July, 1921

A Holder for Rewinding Motor Stators A SERVICE company in Massachusetts uses an interesting device to facilitate holding motor stators during rewinding operations. The device consists of a

ia

How the motor frame is temporarily held on the bench during the rewind- | ing operation tiexible metallic holder constructed of a piece of strap iron. The piece of iron is about 28 in. in length BOLT and is bent into the shape of a U clamp with its upper ends held in place by adjust-

c Ka - dee

—_—_-— — / 1 SNe

Champion Transformers Decrease gasoline con- sumption—give greater power—reduce carbon deposits. They can be at- tached in a few minutes and fromthat time you will have a sweet, smoothly running motor which starts easilyeven in zero weather. YOUR MOTOR PUMPS OIL? “DON’T WORRY! The intense, hot blaze at your plug, due to the Transformer, explodes every particle of oil and gas, giving greater power, and leaving no carbon. DON’T BE FOOLED BY RE- PAIRMEN who tell you that the transformer is not practical. THE CHAMPION TRANSFORMER is not only practical, but it isthe only oxygen burning system of ignition onthe market. Burn more oxygen and less gas! THE CHAMPION TRANSFORMER IS A PERFECTED ARTICLE —the result of fourteen years’ ig- nition ‘experience. It is sold on a money-back guarantee, which comes with every set. Thespecial gauzeco veringoverelec- trodesisa patented fireproof feature. Champion Transformers are suit- able for any engine that uses a spark plug. able rods and bolts. The lower end is bolted to the bench. The whole outfit forms a receptacle with adjustability to a wide variety of motor frames ranging from 6 in. to 9 in. in diameter. Its simplicity is its recom-

h il of : : bg + mendation.— ALLEN P. ity construction CHILD. 1 . . “ s Spring Clothespins Useful in rb e . Patching Tubes st -" TY spring type clothespins are of ad- “4 : vantage for use in patching inner tubes. 8. Secure the tube by means of these to a mM. stiff piece of metal or board tacked on the

edge of the work-bench and the hole to be

CLOTHES- PINS

Spring clothespins are a useful acces- sory in the shop for holding inner * tubes in position while they are un- 4 dergoing repairs 3 Sy

D a covered is held in position for cleaning the own surface with sandpaper and holding it y as ° : ore- securely while the cement is drying. >. When the patch is applied, it has a tendency to curl up at the edges unless = some weight is placed on top of it. Cut — two square sections of thin board or metal, ce place one under the patch and the other over, apply these clothes-clamps and the ron tube can be laid aside with the assurance <a that the patch will stick tightly against the — tube. When a tube is punctured while ve driving, this clamp can be put on and the tube rolled and placed in the toolbox with- Pa. out delay.—G. A. LUERS.

ZINN Attach them yourself. A you need is two minutes and a par of pliers. Over 100,000 satisfied customers are now using Champion Transformers.

i For Pleasure Cars, Tractors, Motorcycles, Gas Engines SEND NO MONEY Write us today and give us your name and address; also the kind of car youdrive. Wewill send youaset of Champion Transformers by parcel post. Pay the postman $1.50 for a four-cylinder set or $2.00 for a six-cylinder set and the Transformers are yours. You also get a free booklet written by ignition experts which alone may save your usual Spring repair bills. THE VAN KERR CO., Dept. 82, 3160 N. Clark St., Chicago

‘a

World-Sweep of Wireless Brings You Big Opportunities!

World’s Fastest Growing Field Opens Big Opportunities to You On land and on sea wonderful o ie gg are eagerly looking for YOU. urely this World-Sweep of Wireless holds a real message for those who want to cash in big on a fascinating, uncrowded field filled with amazing opportunities. A $20,000,000 American corporation has been formed to establish wireless stations in every part of the globe. The U. S. Merchant Marine operates over 30,000 vessels. Wireless is a neces- sity on ships. Huge wireless stations are springing up all over the world. Saint Assise, France; Bordeaux, Ville Juif, and Lyons, France; Japan; Peking, China’ Geneva, Switzerland; Shanghai, China; Fiji Islands; Warsaw, Poland—and these are but a few. Many railroads are calling upon wire- less to dispatch trains and carry_on communication. The Lackawanna, The Louisville & Nashville, The Canadian- Pacific, The Nashville, Chattanooga & St. Louis, are some of them. Brokers, Bankers, Merchants, .News- papers, Manufacturers and other busi- ness concerns are calling upon wireless. John Wanamaker, Goodyear Rubber Co., Chicago Tribune, Standard Oil Co., NewYork Stock Exchange, are onlya few. Farmers are gas Market and Weather reports daily by wireless in all sections of the country. New wireless stations are springing up in every part of America. Belfast, Me.; Cape May, N. J.; East Pittsburgh, Pa.; San Francisco, Cal.; Helena, Montana; Seattle, Washington; Mobile, Alabama —tbese are but a few. The Federal Telegraph Co. is estab- lishing a complete chain of stations on the Pacific Coast. Daily wireless service between the United States and Japan is in full opera- tion.——St. Johns, New Foundland, is operating a large service. South America is planning to estab- lish a chain of stations at Rio de Janeiro, Asuncion, Buenos Aires and Montevideo. One single American concern offers wireless communication between the United States and France, England Germany, Norway, Denmark, Sweden, Finland, Poland, Honolulu and Japan. And these are only a few of the ex- amples showing how Wireless expan- sion is spreading over the whole earth. It brings you amazing opportunities— and you can now easily grasp them.

93 Wireless Expansion is Sweeping Over the World Like Wild-Firel Big ae Are Open Now On Land and On Sea. Share Big-Pay Field. A Wonder You Can hem and the Amazing Future Offered by this Fascinating ful New Invention Makes Wireless Amazingly Easy for Anyone to Learn—At Home in Spare Time. Now Easy to Learn At Home in You yourself know about the enormous world-wide strides Wire- less has made in a few short years. But do you know that now YOU can easily share the amazing op- portunities that have eo up? Do you know that YOU can now quickly and easily learn Wireless at home in your spare time? A fas- cinating big-pay field that you can put your heart into is eagerly calling for you. And now—no matter whether you are already a wireless amateur or whether you are totally unfamiliar with Wireless at the present time—you can _ speedily qualify fully for the wonderful future Wireless offers you! Which for You—Land or Sea? Do you long to visit every nook and corner of the world? Or would you rather locate in a land station near your home or in another section of the country? Wireéless offers you your choice. On the sea fine op- portunities are offered, with the chance to see the world as an officer with luxurious quarters and good pay. From the land, too, comes the call of Nhe new forces that have formed to make Wireless the great- est means of communica- tion in existence. Just a few of the items showing this amazing sweep of ex- pansion are shown here. Amazingly Easy for Anyone Through our remarkable atented invention, the atrometer (given without extra cost to each student), and our interesting home- Spare Time stitute was the original and is today the oldest and largest wireless school in America teaching wireless by mail. This Institute is officially recognized by the U.S. Department of Com- merce, its diploma is given official credit, its name heads the list of schools recommended by the Ship- ping Board. Hundreds of its students have been graduated and have en- tered this uncrowded field. Special Opportunity Now Open The urgent need for operators and the calls which come to us for our students prompt us to make a special offer open to new students for a limited time. Through this special offer your enrollment will be accepted at a special rate and you will receive without extra cost our new course in Wireless Telephony. Mail Coupon for FREE BOOK Tt costs. you nothing to get our interesting illustrated booklet, ‘Wireless, the Opportunity of To- day.’’ Mail coupon today for this booklet and for full facts about our special Short-Time Offer. Fill out coupon now—then mail it today! NATIONAL RADIO INSTITUTE, Dept. 87, Washington, D. C. RUSH THIS FREE-BOOK COUPON National Radio Institute, Dept. 87, Washington, D. C. Send me your FREE book, “Wireless, the Opportunity of Today.”’ your Home Study Course in Wireless Teleg- raphy and your special Short-Time offer. ell me about study course, the National Radio Institute makes it Ee ee se Cocccecccnccececoe easy for any one to learn Wireless at home in spare © Address........ VevuevVececes avew Retasee me. The National Radio In- § City......... oe +9 <Necwceniecnce

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a CRY 2

Evans, carpenter, ast 60, now MAKING $100.00 a week in shop shown here. Gibbard of Mich., age 62, Leseaeal TIRE SURGERY, has shop ‘in small town, writes: ‘Cash receipts for May, June and July; 1920, $30,000.00."" LWA ywooo's EF . is easy to learn. I will teach you in two weeks, Within thier 5 ce 8 roe re started on road to fortune. Car owners EVE HERE demand this NEW repair meth- od, as it DOURLES life of Tires. 28 million tires wear- CT USAND MORE Tire Sur- d badly. ~ MAN can succeed R EASY step into automo- bile industry —the field that bas made men rich. It put $6,000.00 Hy aoe for John W. Blair, Rite. in 12 00 for Fie ming, of a- others afer, re ‘gmone vin this perpere’s for YOU, Investigate! Get dc- Send coupon

Pres., co. 1276 Capito! i ianapotte, Dear Sir: Send full details’ oF Trent cone as I want to get into big paying business quick. Fo Name

ae

NAVARRE— Quality Binocular— Special Price, $37.50 ERE is your opportunity to get a high grade binocular at a low price. Standard 6 power 30 m/m—specifications adopted by all armies in World War as most efficient under all conditions. Ad- justs to strength of each eye. Extremely light. Made by master craftsmen. Beau- tiful satin finish; heavy leather, velvet- lined case; will attract attention any- where. Genuine GRAF LENSES. Only instrument constructed of brass—no clouding of lenses as is the case with ordi- nary aluminum-frame instruments. War contract cancellation price—$37.50—in- cluding war tax. Sent C. O. D. or upon receipt of money order for 3 days trial. Money immediately refunded if you are not entirely satisfied. THE NAVARRE COMPANY 607 J. M. S. Bldg., South Bend, Ind.

anes factory to youFREE « Easiest riding, most comfortable wheel 7 built. We'll ship it to you on approval. \ You'll want it sure when you see the . 18 exclusive features of the splendid 1921 model electrically equipped BIACK BEAUTY

unr Big eolor-illustrated catalog shows large (a variety of styles—describes features Ne ON fully. Choose the wheel and we'll ship aes prepaid on approval without rost. A small deposit and LLAR ‘A WEEK makes it yours. Our direct factory price saves you money—a sav- ing you cannot afford to overlook. 5 year guaranty and 6 months’ ac- cident insurance with every wheel. Send now for big color- illustrated ptm. Ba it’s FREE! Haverford Cycle Company Established 25 years Dept. 387 Philadelphia, Pa. be a Black Beauty Owner Agent

Popular Science Monthly How to Make a Double Socket 2 tee make your own double socket, secure fiber board not more than 1/16 in. in thickness. Cut this in oval shapes—two of them, making them 2% in. in length. Next cut some soft brass as shown in

BEND THIS TAB

o _~ UP AT RIGHT A ANGLE | < oO \ FIG.1

BEND THIS TAB DOWN AT RIGHT q _

ANGLE DRILL HOLE HERE F162 | The first step is the cutting out of the metal base Fig. 1. Cut another piece of brass 14 in. in width, and bend as in Fig. 2 In each of the two pieces of fiber cut four rectangular holes 4 by 14 in., two at each end. The holes at each end should be 3. in. apart, and the distance between the two groups of holes 15/16 in. Five little brass fasteners that can be flanged at the bottom, and the screw portion of an old electric socket complete the necessary equipment, as shown in Fig. 3. Now fasten the screw socket to one of the fiber boards with the brass fasteners, then place the small brass piece in the center of the fiber so that its crooked end is in the center of the socket, and its curved end projects in the opposite direction. Then fasten the larger brass piece so that the tab at its square end also projects through one of the holes through the fiber board into the socket, and its tab at the rounded end projects in the opposite direction, parallel to the tab on the small brass piece. Now fasten the two fiber board pieces together and flange the fasteners. One picture shows how an electric light and an electric toaster may be used from one socket. Half of the plug of the toaster is pushed through the two end holes of the fiber, and the screw portion of the plug is then slipped over the metal contacts.

Here the parts are illustrated before they are assembled

To the left the assembled socket with the top removed; to the right the complete socket with a bulb and service wire Using an Enlarging Camera in Artificial Light VEST-POCKET camera of 214 in. by 314 in. size is one of the greatest com- panions that one can have. Opportunities present themselves at the most unex- pected moments and, when one has a good lens, some re- markable pictures can be procured that are certainly worthy of enlarging. It is out of the ques- tion to carry about a camera making a 5 by 7 in. picture when one is engaged in other means of making a livelihood. The writer is a great believer in the ‘‘Take it small and enlarge’’ slogan, and has been experiment- ing for one year with an enlarging camera, using artificial light. The greatest trouble the writer experi- enced was in getting good illumination. When opal glass or ground glass was used, it took from twenty to twenty-five minutes to get a print on bromide paper. This was a very drawn-out process and required a lot of patience. After using up an enormous quantity of ground glass, opal glass, and electric- light bulbs, the writer tried a condenser consisting of a glass bottle with a spher- ical body. This bottle was filled with water to which were added a few drops of copper-nitrate solution which produced a@ greenish tint and seemed to geatly increase the actinic value of the light. Behind this globe was placed a 50-watt Edison opal bulb, and back of the light a reflector from an. old-style automobile 94

~ Camera, condenser, light, pre reflector must be accurately alined to obtain good enlargements lamp. Bromide prints are now made in from 1% to 10 minutes. Care must be taken to have camera, condenser, light, and reflector all in line, otherwise the prints may be lacking at the corners. The picture will illustrate the arrangement of this apparatus. For determining the length of ex- posure required for various negatives, a rack is made on which are placed about six negatives of various density, each negative marked with the time exposure necessary. All one has to do then is to compare the density of the neg- atives to be enlarged with those on the rack and expose accordingly.—-GEORGE BENDER. Take Care of Nickeled Automobile Parts HE owner of an automobile should not be too vigorous in polishing the nickeled parts of his car, otherwise, after a few months, the brass or steel will show through. In caring for these parts use only the same polish as is used for silver articles and rub only sparingly. Wiping afterward with an oily rag will prevent tarnishing and pre- serve the thin nickel coating for a long time. Parts that are not handled much may be protected from tarnish by coating them with metal Jacquer.—G. A. LUERS.

Page 87

ng aX - for on ed yes ty, ve she eg- ick ER. not led few OW the and rith yre- ong nay em

July, 1921 SEO 21 Jewel Illinois ¢ The greatest watch value ever offered. Unequalled for beauty, accuracy and relia- bility. 21 ruby and sap- phire jewels—adjusted to positions, temperature and isochronism, 20 year gold-filled case. 10 Days Free Trial Wear it for 10 Days at our risk. Note its absolute exactness. If at the end Of ten days you are not satisfied, just send it back at our expense. Knife and Chain Free We are offering for a limited time this handsome gold-filled a chain ABSOLUTELY FREE. Just send your name and address. The watch, chain and knife come to you, prepaid. Give the expressman $8.50 as a deposit, if after 10 days, you do not wish to keep them, return at our expense; your deposit will be refunded instantly. Trial is absolutely free. If you keep the watch pay $3.40 a month until full price of $42.50 is paid. This splendid watch will cost you less than ilcaday. Act atonce. Address Dept. 471-M. Capital $1,000,000 “THE HOUSE OF QUALITY CAPITAL $1,000,000. L:W-SWEET INC. 1650 -1660 BROADWAY, NEW YORK

akeYour Bike FW y Coycey unset: FASY to do and at low cost. Your old “foot power’”’ bicycle can be quickly transformed to a speedy, easy-run- ning high power Motorcycle with the Shaw Mcetor Attachment. Fits any men’s bicycle of any make or size. Chain drive model can be attached in less than an hour. boy can put it on. No special tools or knowledge necessary. SHAW hectic Thousands in use. A light weight 2% H-P motor of wonderful efficiency. Simple to attach. Everything furnished complete. Every owner enthusiastic, All materials are guaranteed. Get one NOW. . PREE Write at once for Free Book and Low Direct Factory Price on the Shaw Attachment, also the Shaw Motor-bicycle--a complete power machine at a low price. SHAW MANUFACTURING CO. Dept. 1467 Galesburg, Kansas Saad

INUNUAVUVUUUUUAYOUUUUAUOU USACE Trained Auto Salesmen Sell Motor Cars—Trucks—Tractors Get into this interesting business which is growing so rapidly and paying big rewards for ability. There isa shortage of trained salesmen—a big demand for the man who knows how to get the business. We offer a complete course covering the entire field from getting prospect to closing sale. Can be easily mas- tered. Inexpensive. Previous auto experience not necessary. Send for details today. LESLIE-DONALD COMPANY 15 West 37th St., New York, N. Y. TNUULUUUUUNANAUAUA AUNT CARPENTRY

By GILBERT TOWNSEND, S.B. A practical treatise for the use of carpenters and wood- workers on simple building construction, including framing, roof construction, general carpentry work, and exterior and interior finish of buildings. 58 pp., 368 ills. Price, $2.10.

Popular Science Monthly, 225 West 39th Street, New York A Swiveled Water-Pipe for Garage Purposes SWIVELED pipe connection with the hydrant as is shown in the illustration is of advantage in the garage for filling the radiator and for washing the car. The connection consists of two lengths of pipe about 1 in. in diameter, joined by means of four standard elbow fittings and a short coupling. This is attached to the water- main lead brought up about 3 ft. from the floor, with the cut-off valve placed on this pipe. The water-main is usually located in the end of the garage farthest from the entrance. The swiveled pipe will permit of swinging the end over the filling cap of the radiator FILLING + mene £ >, ‘itl: 4 a . N ’ 4.9 vs

POSITIONS FOR WASHING CAR

ee tT Qe ee ere.

\" PIPE AN FITTINGS D SECTION OF GARDEN HOSE 4 IL GARAGE =! Where much cleaning and washing has ~ to be done, as in the wagon-shed or garage, this swiveled pipe will be very useful

and this is filled without splashing the water over the floor, shoes, hood, etc., by simply turning the water on. A 4-ft. section of garden hose is ample for use with this extension when washing the car. The hose is fitted with a screw connection that may be readily unscrewed. When the Pedal Faces Are Worn Smooth ye the faces of the clutch and brake pedals are worn smooth after a period of usage, an uncertain foothold is experienced that is still worse when the shoe sole is slippery wet. Two methods are suggested for improv- ing the faces of the pedals under these conditions. The first is to use a diamond- point chisel and strike a number of rough- ening spots across the smooth faces of the pedals. This can be done without remov- ing the parts; simply chip spots about 14 in. apart to make the surface stand out. Another meth- od that is ad- vised is to secure short ends of brake - lining to each of the pedals with small screw- bolts at eachrcor- ner. Thesections of brake - lining provide a good gripping surface for the shoe that makes the opera- tion of the brake and clutch posi- tive in either wet or dry weather. ROUGHEN WITH DIAMOND- POINT CHISEL

Several methods of rejuvenating old and worn pedal-faces 95

43% Complete

One Girl does the Work of 50 Typists 75 good, sharp form letters a minute. This is what can be done in your own office by any stenographer or office boy, with a ROTOSPEED STENCIL DUPLICATOR This machine prints anything that can be typewritten, hand written, drawn or ruled. Not only form letters that exactly duplicate the typewriter type— but bulletins, ruled forms, price lists, notices, menus and .ards. There is no type-setting, no cuts, no trouble and no delay. 1,000 Copies for 20c This machine saves almost the entire cost of form letters and a big percentage of printing bills. It isused by thousands of manufacturers and merchants for sales and collection letters, factory and office forms. It is used by professional men, banks, schools and churches. Price— $43.50 The Rotospeed has a semi-automatic feed, self-adjusting impression roll and six other exclusive improvements. There is only one model and no acces- sories. It is not sold through salesmen and you save all other selling expense by dealing direct with the factory. Our Free Trial Offer We offer to place the Rotospeed in your office on trial, completely equip- ped for all kinds of work and with suf- ficient supplies for 24 different jobs. The machine must sell itself. Write for our proposition and the Rotospeed Booklet. Let us show you how others in your line of business are increasing their profits and saving expense the Rotospeed way. Just sign and mail the coupon or pin it to your letterhead. THE ROTOSPEED CO. 560 East Third Street Dayton, Ohio MAIL NOW! The Rotospeed Co. 560 East Third Street Dayton, Ohio Please send me booklet, samples of work and details of the Rotospeed free trial offer.

POPS H HEHEHE SHEE ESE EE EEE eoveese

Page 88

Po Sean Heb ISR ae foe et rer gr eee oe oe FIAT pa ERAN ah gles FRA i iy he az RI ar ere een nye Do You Know How to Save Money On Your Automobile? Here are the best books on operation and repair The Model T Ford Car Its Construction, Operation and Repair, Including the Fordson Farm Tractor, F. A. Lighting and Starting System, Ford Motor Truck. By Victor W. PAGE. 410 pp., 153 illustrations. Price, $2.00 The Modern Motor Truck Its Design, Construction, Operation and Repair. By Victor W. PAGE. Treats on all types of motor trucks and industrial tractors and trailers and considers all types of trucks, gasoline and electric, and all varieties of truck bodies. 800 pages, 750 illustrations. Price, $5.00 Motorcycles, Side Cars and Cycle Cars Their Construction, Management, and Re- pair. By Victor W. PaGeE. Describes fully all leading types of machines. 500 pp., 350 ills., 5 folding plates. Price, $3.00 Automobile Ignition, Starting and Lighting, with Questions and Answers. By CHARLES B. HAywarpb, M.S.A.E. A comprehensive analysis of the complete electrical equipment of the modern automo- bile. 1,024 pp., 740 wiring diagrams and ills. (including 128 blueprint diagrams). Price, $3.75 Storage Batteries Simplified Tells how to charge, care for and rebuild storage batteries. Also outlines their in- dustrial uses, including how they are used in central station’ standby service, for starting automobile motors, and in ignition systems. 208 pp., illustrated. Price, $2.00 Aute-nobile Repairshop Shortcuts Contains over 1,500 time and labor saving methods and devices that have proven ex- ceptionally helpful in repairing or adjusting engine clutches, gear-sets, running gears and bodies, etc., and in managing and equipping shops. Here is the opportunity to study the methods of over five thousand experts who were all striving to find a better way to do some job and to shorten the time required to do it. 1,500 illustrations. Price, postpaid, $3.50 Automobile Repairing Made Easy By Victor W. Pace. A thoroughly prac- tical book containing complete directions for making repairs to all parts of the motor car mechanism. 1.056 pp. Price, $4.00 Popular Science Monthly 225 West 39th Street New York City Popular Science Monthly For Measuring Iron Pipe, Try This Gage N order to save time and insure accu- racy in measuring the sizes of pipes in dark places, difficult of ac- cess, the pipe gage described below was made. It will instantly give the conven- tional standard sizes of standard wrought- iron pipe from %-in. to 2'%-in. inside di- ameter, these sizes being most commonly used. In order to make this gage, it is neces- sary to know the cor- rect outside diameters of pipe from %-in. to 2)4-in., and for the benefit of the reader and prospective maker they are given in the following table of equivalents. win. = 40in. lin. = 1.31 in. Win. = 54 1n. 14% in = 1.66in. 3% in. = 67 in. 1%in. = 1.90 in. 4%in. = 841n. 2 in = 2.37 in. 34m. = 195 in. 2% in. = 2.87 in. Procure a piece of sheet brass or copper 4 in. wide and 5!% in. long and 1/16 in. thick. The plan of the gage can be laid off on either the metal or a paper template. First lay off a center line and at a point 14% in. below the top make an intersecting mark. At the other end of the metal, or 414 in. from the mark above, measure 114 in. on each side of the center line and then connect these points with the first point laid off. These two lines are the lines A and B on the diagram accompanying this article. Now take a compass or pair of dividers and set them to a diameter of .40 in. or radius of .20 in., which is the outside diameter of -in. standard pipe. Placing the needle-point on the center line, make a circle so that the circumference co- incides exactly with the two lines A and B. This point can only be found by manipulat- ing the compass until the points required coincide exactly. Now set the compass to diameter of .54 in. or a radius of .27 in. Xa « This diagram shows how to mark the gage before the filing of the notches 96 Here is clearly illustrated the method of correctly using the gage for the 4-in. pipe size and, moving slightly down the center line, make another circle in a like manner. Proceed likewise with the rest of the diameters up to the 214-in. size. See plan of the template here- with. Draw radii in.each » Of the circles so laid , out and perpendicu- lar to the two sides or lines A and B. These intersections are the points of con- tact for the pipe when it is placed in the gage for measure- ment. When they are laid off properly there will be ten of these points on each leg, one for each pipe size, 4% in. up to 2% in. Cut out the gage with a fine hacksaw to the shape given in the drawing, being careful to follow the lines A and B care- fully and not cutting inside of them; it would be better to cut a little outside the lines and then smooth down carefully with a file later on. Use a “rat- tail’ file to file out the spaces between the measuring points on the legs of the gage. In use, this gage is simply placed over the pipe to be meas- ured and the reading taken at the point where the pipe fits. Numbers corresponding to the usual pipe sizes 4 in. to 2% in. should be punched or stamped with steel letters or number dies on the sides of the gage. If it is preferred, the markings and num- bers may be etched in the metal with nitric or hydrochloric acid and the etched parts filled in with black varnish or black- ened with chemical stain.—B. F. DASHIELL. The gage should fit a 1-in. pipe like this Use Old Tire Rubber for Insulating yu working on an electric line running alongside of a road, the writer experienced considerable trouble by leakage on the high tension wires. Finding an old tire on the road, suggested to him the idea of using parts of the rub- ber for insulating purposes. It proved success- ful and by em- ploying pieces of the old tire for insulating the in- sulators, theleaks along the line were stopped. — J. G. SIMPSON. HIGH TENSION eachiioea PIECE OF OLD TIRE Leakage prevented on wires by tire rubber

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Cw wwe a * we © BR tt — ~~ © 8&8 BD he al be TS N- th ed k- ne she by ing im yN R e

July, 1921 Renew All the Balls When Some Are Broken HEN a broken ball is found in a ball- bearing the frequent practice is to ubstitute one new ball for the fractured me. This is an incorrect practice and the esult is that the new ball, which will be everal thousandths of an inch larger than BEARING-BALL Ax

itil SMALL = SQUND BALL |

ar ____ IMPERFECT

Sound sessticaalhs will bounce into the box, defective ones will fall short those adjacent to it in the bearing, will carry practically all of the load. Either the excess load will cause the larger ball to cut the seats of the raceways or the ball will be cracked, due to the over- load. Renew the entire number of balls as an assurance from more extensive repairs. The balls are far less expensive than the races, and it is therefore economy to dis- card all the old balls, unless one can be secured by testing with micrometers for the exact size. A test of steel balls consists of dropping them on a faceplate. A ball with a hardening crack will rebound but little, if at all. To determine more accurately the hardness of the individual balls, roll them down a fixed incline to strike a faceplate, setting a small box a distance from the end of the incline for the balls to rebound and fallinto. Any ball that fails to bound the distance from the end of the incline to the container is either soft or cracked and it is unwise to place it in a race.—G. A. LUERS. Changing a Folding Rule into a Screwdriver FTER I had broken a number of pocket rules while trying to use the end for turning screws, I made an attach- ment for my 6-in. scale that is shown in the illustration. The hardened and tempered

FIG.1. With this attachment your folding rule can be turned into a screwdriver tool-steel screwdriver point is clamped to the seale by a knurled screw. To prevent the screwdriver from cutting the pocket I made a guard of a piece of cold rolled steel. When not needed, the attach- ment can be taken off the scale and carried

separately.— W. BuRR BENNETT. GREAT SCOTT VAPORIZER

Sh aa 30% to 50% Saving of Gas Perfect Lubrication No Carbon

Easier Starting |

Gk EAT

VAECK (ZEK FATE JULY ¢ |

saa Less Heating of Motor 7 PAR

GUARANTEE bs ee $100 in additi spphshcnteams. Reding inal investment to any purchaser Pa CREAT “SCOTT atisnent who can prov an in any of the following claims 1—To gir <7ot0 0% additional mileage per gallon of gasdline over that secured by standard equipment. amg es lubricating by using less oil and grease 3—To eliminate all or a large percentage of carbon. 4—To make starting easier in the coldest weather. — Less heating of all parts of motor due to absence of carbon. NOTE. The above guarantee will be carned aut to the letter on condition the user of the GREAT SCOTT VAPORIZER complies with the instructions which accompany each VAPORIZER GREAT SCOTT VAI ZER CO.,INC. Grand Rapids, Michigan 5O Norris Bidg.

and

AutoOwners Made for Write us if your dealer can’t supply FORD Z you. We'll see that os ERLAND Z you get a Vaporizer. ‘Oo Zg Dealers a on. Write for exclu- Z sive agency inyour NASH district. We assist G.M.C, by scialee to you ee inquiries from our RAL advertising. UNION Z,

From 75% to 100% More Mileage Per Gallon Carbon, heating of motor, defective lub- rication, hard starting and minimum mileage are the results of poor quality of gasoline obtained today. Great Scott Vaporizer eliminates all this trouble. Does away with impure gasoline mixture to enter motor. Sold under an absolute $100 and money back guarantee to carry out above “5” points. Works automatically. No moving parts. Cast aluminum construction. Easy to put Sold at leading garages and accessory stores Great Scott Vaporizer Co. 30 Norris Bldg. Grand Rapids, Mich.

Seat” _ residue by re-refining before allowing SVAN VAAN AAA ANA TAA CAMA Write for further information. RAS Ze Sh LAL, LU LLL LL Lh LL,

. New Big No. 15-225 pp. Wireless Catalog Wireless catalog mailed for 12c in stamps or coin. Any wireless amateur will tell you it isthe one catalogue to have. Asan ency- clopedia of information it is in- valuable. The largest and most elaborate radio catalog pub- lished. Values that cannot be duplicated elsewhere. THE WILLIAM B. DUCK COMPANY 224-228 Superior St. TOLEDO, OHIO

Build This Car This nifty little car driven by gasoline can than ever, ister Daria to build thie lnd's cor SYPHER MFG. CO., 174 Sypher Bidg., Toledo, Ohio Wale Build and Fly Model S® Aeroplanes Build a Model A like a real one. Drawings and Building ro FI Instructions you can easily buil exact, 3ft. Gubticates of Big Aero. lanes. Send now for Drawings and nstructions for the one you wil! build: Curtiss i -2T raining *Plane, res Battle ines Naval Seaplane, Curtioe Military Tractor, Bleriot en ~ cn Nieu- port Monoplane, ‘Taube Monoplane Catalogue of IDEAL Model (Postpaid renee: a and a” ePnee: 5c Postpa Ideal ae Supply Co. . Houston & Wena Sts. N.Y.C.

opie yy will fly With AL poate

nt tn a fow houreet home you can easily be- ones homers, fistiet en, ep, Fox-Trot and all y Anns dance d.

WOLFE’s pnt DANCE STUDIOS Buitding, Kansas City, Missouri.

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SER IE: EAT I OE I ETE A SE TP LE CTI ETN OE RUSE

REEF AEE PRG SEE a BEATE op alnin BBE TEE pe a ee Fearne emer om ep

Canadian |) ay National "cysrem! FRailways oe AG

CANADA Calls Youl Vacation Land of Ideal Summer Climate Hay fever is unknown in this clear, pine-and-balsam scented air. Unlimited territory to choose from—cloud tipped mountains and rugged foot hills inviting exploration; wide valleys of woods and streams and wild flowers; turquoise lakes with sandy beaches; the restful relaxation of camp life or the luxury of the finest hotels. In Canada, your Ideal Vacation is realized: Al- gonquin Park — Muskoka Lakes — Great Lakes Cruise—Georgian Bay—Lake of Bays—Kawar- tha Lakes— Timagami— Nipigon — Quetico— Minaki—Lower St. Lawrence and Maritime Provinces. Fishing, boating, bathing, golf. A summer play-ground in the great out-of-doors. Jasper Park, Alberta, and Mount Robson Park, British Columbia, embrace the scenic mountain wonders of the Dominion. For full information write Canadian National or Grand Trunk Railways at any of the following addresses— Ask for Booklet E, mentioning districts that interest you. ea 294 hyn ay > New York, 1270 Broadway alc, 101 mber 0} Pittsburg, 505 Park Bldg. Commerce Bldg. St. Louis, 305 Merchants Soe. ae <td Laclede Bldg. incinnati, 406 Traction Bldg. Detroit, 527 Majestic Bldg. —_ Cor. 4th and Jackson ‘ty, 7 2 z ‘Eacharey Bldgs "7 San. Franciaco, 689 Market Minneapolis, 518 Second St. Ave., Sout Seattle, 902 Second Ave. Fishing, Hunting and Camping Real fishing and hunting in virgin streams and unspoiled big game country in NOVA SCOTIA, NEW BRUNSWICK, QUEBEC, ONTARIO, ALBERTA and BRITISH COLUMBIA. For full information write G. T. Bell, Passenger Traf- fic Manager, Grand Trunk Railway System, Montreal, or H. Melanson. Passenger Traffic Manager, Canadian National Railways, Toronto.

“Reo” Cluster Metal Shingles, V-Crimp, Corru gated, Standing Seam, Painted or Galvanized Roof- ings, Sidings, Wallboard, Paints, ete., direct to you at k-Bottom Factory Prices. Positively greatest offer ever made. Edwards ‘‘Reo” Metal Shingles cost less; outlast three ordinary roofs. No painti airs. Guaranteed rot, fire, rust, lightning proof. Free Roofing Book Get our wonderfully low prices and free samples. We sell direct to you and save you all in-between dealer’s No. 198. =

vSs re er = ‘LOW PRICED GARAGES

‘| —__—_______ HrotrootSwacargen set od ol upany place. Send postal for Garage Book, showing styles. {IN Yqut) ae el HE EOWARDS MFG. Co., ¥48-798 Pike St., Cincinnati, 0. Roofing Book

How to Prevent a Rubber Floater from Swelling AVING found cork unsatisfactory as materia! for a floater in the flush-box of a toilet, I decided to use rubber. I found that the rubber ball, being constantly sub- merged, would swell at least 14 in., causing it to strike the overflow pipe which in turn pre- vented proper seating. By placing a small copper band around the ball as indicated in the illustration, I prevented the swelling of the ball and it proved satisfactory for several years.— ERNEST OFELDT.

— BALL COPPER BAND The copper band prevents the ball from swelling Spirit-Level Insures an Even Saw-Cut FoR a guide in the even cutting of small but important work, such as dove- tailing and the like, fit your saw with a spirit level. An ordinary glass spirit level, enclosed in an odd length of suitably sized gaspip- ing, is all that is needed. At each end of the pipe, cut the tube down about 1% in. on one side; then cut

When horizontal cuts have to be made, a spirit-level is a great help halfway across, some 1% in. from the ends, so that when opened they form the lugs, as shown. If the accessory is to be a permanent fixture, drill each of the lugs, and the back stay of the saw, to take a rivet or small bolt.—GEORGE H. HOLDEN. Protect the Young Plants Against Cutworms 1S lave the spring and early summer the cutworms cause great damage in gardens and on truck-farms. They love the tender plants and feast on them wherever they can find them. The picture illustrates a method of pro- tecting your plants from cutworms by a paper barricade. A piece of paper is rolled in the form of a cylinder or cuff. The over- lapping ends of the paper are fastened to- gether with paper-clips. Then a 3-in. rill or ditch is dug around the plant, the paper cylinder is placed in the cir- cular hole, andthe soil is replaced. This paper bar- ricade will effec- tively protect the plants, provided, of course, that it is put in posi- tion early enough. —KE. BADE.

Cutworms cannot climb this barrier 98 Popular Science Monthly: Oh You Skinny/ Why stay thin as a rail? You don’t have to! And you don’t have to go through life with a chest that the tailor gives you; with legs you can hardly stand on. And what about that stomach that flinches every time you try a square meal? Are you a pili-feeder? Do you expect Health and Strength in tablet form—through pills, potions and other exploited piffle? The only way to be well is to build up } your body—all of it, through Nature's } methods — not pampering the stomach. It is not fate that is making you a failure; it’s that poor emaciated body of yours; your half-sickness shows —_ in your face, and the world loves healthy people. So be HEALTHY— STRONG—VITAL. That's living. Mention the ailments upon which you wish Special Information and send with a 10c piece (one dime) to help pay postage on my Special Talk on Thinness and my es motion f Health, Strength and "t put it off—send for my free book low. LIONEL STRONGFORT Physical and Health Specialist vhetedeet tee Dept. 345, Newark, New Jersey

NTERS, Shipfitters, Bricklayers, Structural, Concrete and Sheet Metal Workers, Electricians, Mechanics, Plumb- ers, Pipefitters, Boilermakers —can you read Blue Prints and hold a big job? If not, learnhow. It will help you hold your job—it will get youa better job—it will increase your earning peck: Write for Catalog B, stating trade, DON'T DELAY—it means more money! BE A DR AFTSMAN Earn $35-$150 Week Draftsmen are in dema nd. Books and tools FREE. Write for Catalog G. DO IT TODAY! Columbia Correspondence School £st.1904 Carroll Dept. Drexel Bidg., Phila, Pa.

(aes OES

“DON'T SHOUT” Apyone can adjust it. Write for booklet and testimonials. THE MORLEY CO., Dept. 797. 26 South 15th Street, Philadelphia. “T hear you. Ican hear now as wellasanybody. ‘How?’ With THE MORLEY PHONE. I'vea pair in my ears now, but they are invisible. I would not know I had themin, myself, only that I hear all right.’ The Morley Phone for the DEAF is to the glasses are to the eyes. Invisible, comfortable. weightless and harmless. Over one hundred thousand sold.

ears what

quality Cartridges .22 cal., shipped express 50c per 100. . Blank LIBERTY SPORTING GOGDS CO., Gox 782, Bept. 599, CUICAGO

EARNENGINEERING Electrical and Mechanical Engineers receive fabu- lous salaries. Thousands wanted. months to 2 years. Practical-Technical training under experts. Not a trade school but a Practical-Technical College teaching electricity, steam, gas, auto-electric, armature winding, drafting. Extensive laboratory and sho i t. Degrees awarded. Day and night sessions. Enroll any time. Don’t judge us by size of ad. Write for free catalog. FINLAY. ENGINEERING COLLEGE, 1002 Indiana Ave., Kansas City, Mo. :

eS ee ee ee ee —— oo aw | | Be Your Own Boss! ! In the outdoor amusement business. Our games earn big money anywhere people congregate for amusement. Parks, Carnivals, Fairs, Home-comings, Reunions, etc. Pleasant, easy work. Noexperience necessary. Small i investment, big, sure profits. We have made hundreds of people independent. Write today for literature. PENN NOVELTY CO. | 908 Buttonwood Strest, Dept. B. Phila., a

Page 91

sold. eIphia. L

os

(9 oF 4 or 5 Om itt ites nee eam o=

July, 1921 EAS To Play To Pay

(None genuine without this trademark) True-Tone Saxophone opens the way for you to greatly in- crease your income, opportunities, popularity and pleasure. Easiest of ail wind instruments to play 4 —you can learn toplaythescale {4 in an hour and in a few days (§ be playing paneer airs. Prac- jure tice is a pleasure. Tells you when to use Saxophone Book Free Saxophone — singly, in sextettes, or in regular band; how to Sranepepe cello parts in orchestra and many other things you would like to know. ° You can order any Buescher instrument Free Trial and try it six days. without obligation. If perfectly satisfied, pay for it on easy p ts to suit your convenience. Mention ‘the instrument interested in and a complete catalog will be mailed free. (26) BUESCHER BAND INSTRUMENT CO. Makers of Everything in Band and Orchestra Instruments 3126 Buescher Block, Elkhart, Indiana

The Boy’s Work Room Where charts, diagrams, drawings, pictures and other things are to be displayed you avoid injuring the walls when you use ‘Moore Push-Pins Glass Heads—Steel Points A twist of the wrist places them firmly in position. Use Moore Push-less Hangers for heavy pictures. Hold up to 100 pounds. Suggest a use and we'll send samples free. Sold by Hardware, Stationery, © per Drug te Photo Supply Stores ] 5 oa every where “ Master Keys These five different keys are the only set of its kind to insure your safety and. serve for emergencies. They open and test thousands of different door and padlocks. When you are away or asleep how safe is your lock? Or should you lose your keys canothers open? It’s better to know than worrv or be sorry. Don’t delay; only, $1,00 for complete set with novel key chain.

Repairing a Plane Having a Broken Set-Screw a peng iron planes of the class shown in the cut, are commonly rendered useless by the wearing out of the thread of the cast-iron set-screw, long before the cutter is worn out. A new set-screw may be in- serted in the following manner: Remove the curved clamping-iron from the plane, place the point of a 44-in. twist-drill at the threaded hole and drill clear through the iron. Obtain a 14 by 11 in. round-head stove-bolt with a nut. Make a sheet-metal tongue of the shape shown in the small cut and solder the nut to it. It will be seen that a right-angle bend is made in the tongue to assist the solder in

If the set-screw of your plane is broken, the tool may be mended as suggested here holding the nut. The hole for the bolt is drilled in the tongue before the nut is soldered on. The tongue hooks into the opening of the curved iron lever and keeps the nut from turning. - The dimensions of the bolt given are for one to be used with a small plane, say a 7-in. plane.—C. H. PATTERSON. A Flexible Grinder without a Flexible Shaft Kgresndiahoming grinders with flexible shaft- ing extending to the cutting-wheel are convenient for various sorts of work in the shop or garage. A grinder with some of the flexibility of this type can be constructed

oo — ——— ——————

WROUGHT-IRON PIPE

i DRIVE- SHAFT IRE. CABLE x. PIPE. CAP GRINDINGr WHEEL This arrangement gives great flexibil- ity to the grinding-wheel without a flexible shaft from practically any electric motor with an extended shaft running in a small support- ing wrought-iron pipe. The motor is suspended from thé shop ceiling by means of a wire that is hooked to the motor, while the shaft extension is free to be moved to the desired grinding job. With this arrangement a motor of any size is serviceable and the pressure from the grinding-wheel is not transmitted to the motor bearings. Hooks over the several benches in the shop will permit movirg the motor to any

MASTER KEY CO. #Merhsttsr Side:

desired location.—G. A. LUERS. 99 QQHavana iduins SECONAS

st Made of Imported Havana H from our own plan- Picadura, tations in Cuba— same quality tobacco used in 15c cigars, They’re not pretty, no bands or decora- tions, but you don’t smoke looks, Customers call them “Diamonds inthe rouch”

Send money with order or pay on arrival. NONE SOLD After August Ist at This Price and Not More Than 100 to One Smoker Money refunded if you don’t receive at least double value. When order- ing specify mild, medium or strong Your check accepted. Our references, Dun or Bradstreet’s or any Bank. To Each Purchaser of 100 Edwin’s Genuine Havana Seconds, we will extend the privi- lege of ordering, for $1.25 addi- tional, one of Edwin’s ‘‘SAMPLE CASES” containing one sample cigar each of our 12 Best Sellers— all Bargain Values—priced up to $30.00 per 100. Include this in your order—it’s the biggest sam- ple value ever offered.

geaese mention cience EDWIN CICAR CO. 25352-2558 THirnp AVENUE Largest. Mai! « > New Yorx City Order Cigar House In The World, THAT TIRESOME DAILY GRIND BE A RAILWAY = TRAFFIC INSPECTOR EARN UP TO $250 per Mo. Fascinating, professional Work When ordering, h Popular

yf Travel—see the country. All expenses paid. Meet big offi- cials, Splendid opportunities. Position Guaranteed at $110-and- expenses per month to start after 3 months spare-time study. Any average man can qualify, and soon earn up to $250 per month. Enter this new profession. Very moderate fee, refunded if position not obtained. 1500 Men Needed at once! Write, today for free Booklet D-228 Standard Business Training Institute Buffalo, N. Y.

“THE Vest Pocket Lawyer’’—Here at last—in a single volume—a complete la w course—clearly] analyzed in under- standable English. It is a daily guide—a manual of refer- ence for the business man—the law student—the justice of the peace—the notary public—the farmer—the clergyman—

the merchant—the banker, the doctor. 360 pages, 112 legal forms. Price, postpaid, $1.50. Book 3 Poepu. Science Monthly, 225 West 39th Street, New York,

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IWant My Boy to be ““Somebody”’ You, as a Mother, know better than anyone else how dearly i ? | you hold your boy’s future. You want him to reach the top —earn a big position with an income in proportion. Your ambition for his success is the most natural thing in the world. Encourage him by showing your in- terest. He will do anything for you, his Mother, and you'll be proud of him and his success in after years. } Thousands of Mothers Know What We Have Done forTheirSons We can do the same for yours. Call him to your side right now—read the list of positions open to him, with the | big pay they bring. Ask him which Bit) | position he would like best. Then mark the coupon and mail it to us today. We will send you a book taking up the subject in which you are interested and telling of the wonderful successes other Mothers’ sons have made. Ask- ing for it doesn’t obligate you in any , ) way. It will not cost youa penny be- i yond the price of a postage stamp. Men AE RR

j Mail the coupon today. : 4) . Bi American School oy Dept. G-B, 75 Chicago, U. S. A. 4 SPS SS Sl A A A A A A Fk o AMERICAN SCHOOL es Dept. G-B,75 Chicago, U.S.A. LM My boy wants job checked; tell us how to get it. H |) ) iii Architect jf... Lawyer $5,006 to $15,000 t j «sae, 202000 to $15,000 | ...... Mechanical Engineer lL) iii fe Building Contractor 84,000 to $10,000 Hi 5,000 to $10,000}... Shop Superintendent |) } Ri feo meso 5 83,000 to $7,000 Fs : Oo B Di ...«..Automobile Repairman | ***** menaad Cn oF | sot pe 7000 tO $4,000 | Steam Engineer sna Civil Engineer 000 to $4,000 $5,000 to $15,000 op egy er Structural Engineer --+--Foreman’s Course 000 Bit $4,000 to $10,000] py. $2,000 to M4, || a rn Business Manager | --- jotoplay dy 000 i __ $5,000 to $15,000 a TLL, .—l VD a Certified Public Ac- | ---" weed » yr Ria countant $7,000 to $15,000 Teleph. __ to $5, Ti Accountant x4 AnBitor, soteee elep one ‘B00 to $5,000 | . ) ee jer Draftsman & Designer ee Telegraph wagloces Mt J 0 $4, D 0 90, a eo Electrical Engineer _| ...... High School Graduate 1. $4,000 to $10,000 4 In two years . 4 csseod General Education | ...... Fire Insurance Expert i In one year $3,000 to $10,000 if q : Name. a Bi Address...

Buttoning a Drawing-Board to a Music-Stand HAve you a light music-stand with a revolving and adjustable top? You may use it as a support to a drawing-board by following the directions here given. The two parallel buttons on the under side of the drawing-board are placed so an mace THIN STRIP LE BE S574 3 Ht} \\| | ZA tuys, | HW ttAp yu | A |

MUSIC

3 = STAND TOP DRAWING BOARD Four turn-buttons on the under side of your drawing-board will make a drawing-table of your music-stand that they fit tightly against the two oppo- site sides of the music-stand top. Four buttons are fastened to the battens by means of wood screws and washers so as to engage the four corners of the supporting top of the stand and hold the drawing- board in place. If the battens should not be thick enough for the top of the music-stand, they can be made higher by placing thin strips of wood or pasteboard under them. How to Make a Hot-Water Bag from a Tube i you have an old inner tube for which you have no other use, you may take part of it for making a hot-water bag. A small hose-nozzle with a tight fitting screw cap is cemented into an opening cut in the tube. The ends of the bag are closed by cement- ing them. Such bags are always useful and it will be found advanta- geous to convert several pieces of the tube into hot- water bags, in or- der tobe prepared Hot-water bags are for emergencies. easily made from —C. A. BLACK. old inner tubes

ENDS CEMENTED A Superior Photo-Print Drying-Frame ISHING to dry some photographic prints more rapidly than could be done by drying them on cheesecloth, I con- structed a frame for the purpose, which gave very good results, allowing the prints to dry well and at the desired speed be- cause of a circula- tion of air superior to that obtained when drying on cheesecloth. \ The frame is S"woop strips ‘sTRING made of 1/28-in. Prints dry quickly wood strips and on the network of _ is 2 ft. long and string stretched 1 ft. wide, latticed over the frame over with twine. Thesize mentioned was the most suitable for my particular need, but where requirements are differ- ent, it may be altered.—H. K. Capps. 100 PHOTO PRINT

Popular Science Monthly 3 tc ; 1s | 400% MONTH ‘OU can now quickl: alify for a good paying job Ye the Auto snd Tractor eld. At our great: ag son you learn in a few weeks how to Mo tine just and repair all UCKS an makes of AUTOS, TRACTORS, GAS ENGINES. - Big Salaries for Trained Men Miweanes, Motor “cehoot wave: theme DONT LET WOUR jwauke: 01 e OPEORTUNITY SLIP 1 Special Low Tuition NOW! FRE A fine Kit of 28 tools worth $17.60 is given to every- one who enrolls now. They are yours to take hom vanpecamamcmeas Vi ¥ our new **Making You Master of the Auto.’’ Get full ijecmation. A letter or e wi 5 SPECIAL OFFER. tu MILWAUKEE MOTOR SCHOOL Dept.si02 . 555 Downer Av. Milwaukee, Wis.

ON CREDIT oS, WATCHES 5 ~~ Gis Send For Catalog t > \) y F-> DIAMONDS es, WIN HEARTS bY Special Bargains “ in Diamond Engagement Rings and Solid Gold and Platinum W Rings, Diamond-Set ; Alsoa splendid assortment of the & mew engraved, pierced Rings, # White and Green Solid Gold, fine brilliant Diamonds; Dia- frond La Vallieres, Bar Pins, earl Bea@se Scarf Pins, Cuff Links Watcaes, Wrist Watches, ete, Send \ today for Catalog and make your see lections. We pay all shipping charges. \ Credit Terms ny cogent ——— down, balance in eight equal amounts, payable monthly. LIB BONDS ACCEPTED. SOF TIS !='ss oes = BROS& COLE «STORES tn LeaviNa civics

NY <

~) AUTO OWNERS Save half of your tire cost by using ry ool +4 o-

AA) Double-Mileage, Double-Tread ey Tires, Guaranteed 6O0CO Miles. ie ry} We lead, others try to follow. ee. They are reconstructed of highest rr) ie material — hardly ever blow s4) out. They are only guaranteed for ath miles, but have run from 8000 ey to 10,000 miles. Order today at bY these low prices: es Size Tires Tubes RPA 30x38 05.50. $1.60 'e &; eee eer, 1.75 es | RR 6.76..... w-» 1.85 ete § 32x36. 7.00. 2.00 hPAY 3ix4 00 2°25 ry 32x4 25 2.40 33x4 8.50 2.50 34x4. 75: 2.60 BR iicccstsoscense | RRR 3.00 x4hg 11.00. 3.15 ID icoex.ecaseecin 11.50..... 3.40 x5 75. 3.75

RELINER FREE WITH EVERY TIR Send $2.00 deposit with each tire ordered, balance res shi C.0. D. ped subject to your examination. State whether S. S. or Cl., plain or non-skid is desired, All same price. By sending full amount with order you cap save 12per cent—our speci -with-order discount. DOUBLE MILEAGE TIRE & RUBBER biel 2035 W. Harrison, Dept. 102, CHICAGO, ILL.

Save more than half. J/f2% Big Stock of New and direct from U.S, ; Every article positively guaranteed. : HUNDREDS OF BARGAINS Army Blankets, shirts, shoes, raincoats, breeches, overalls, blouses, underwear, boots, puttees, army tents, paulins, camping outfits, etc., all at prices way below cost. SEND TOD AY FOR BIG FREE BOOK fully ~~ v # illustrated; contains prices on Gover you cannot afford to miss. 9) die Co., Dept. 113 Kansas City,Mo. World’s Largest Dealer in Army Goods (Est. 1908)

Page 93

bl ila ‘Ss te July, 1921 Why Not Build a Toadstool in the Garden? ITH a modicum of skill and artistic taste any owner of a garden can build an attractive giant toadstool to ornament some shady nook among the trees. , The stem may be made of natural wood, either with or without its bark, or of cement molded to resemble the stalk of a toadstool. On top of this post the um- brella-like structure of wood is placed that is afterward covered with lichen or moss- ee ty ‘J + This giant toadstool, fashioned by human hands, lends an oddly pictur- esque touch to the garden covered bark, preferably the grayish bark of the white birch. If the top of the giant toadstool is large enough, it will serve as a shelter against sun or rain.—FELIx J. KOcH. Folding Trestle Jacks for Paperhanger or Builder NE form of trestle that the writer observed a paperhanger using re- cently, is of especial advantage for the reason that it folds and is readily trans- ported in a small car. It consisted of two half-trestle jacks joined at the center by two strap hinges HINGES —| SMALL HOOK AND SCREW- EYES Paperhangers will find this folding trestle strong and easily carried and held open by means of a screw-eye and bent rod catch. The construction of this trestle is simple. Hinges of practically any size can be used, and when folded these can be readily piled up upon each other, occupying very little room. Inasmuch as the trestle can .be made any height desired, the idea would be of equal use for the builder. Similarly in halls or places where public suppers are held, these trestles would serve as sup- ports for the table-tops and could be con- veniently stored in closets when they were not in use.—G. A. LUERS. nearer to men : in East and South. and Tractor Business Make a good business deal! Get the knowhow of Auto Mechanics in 6 to 8 weeks at this greatschool. Top sal ing for your Rahe Trained Skill. fae Trucks, Tractors, etc., must be kept going. Their owners lack the knowhow on repairs. ney will pay you big money for your Rahe Training as an expert Auto Mechanic. Get a High-Pay Job Quick! My advice to any man 16 positions wait- he 8 million cars, years and up is to get into Rah the Auto Repair Business right now! Pays highest and needs most men. Most other trades are overcrowded and are cutting down wages. Auto Flying tear School nati brings @ Rahe Training™ Saves railroad fare. You train your hands by do all kinds on real autos of Don’t say you can’t—that you are not mechanically in- clined. Nearly 40,000 men are Rahe Graduates, Few gge= had any Special Bent for mechanics, Yet Rahe trained F— men hold high-pay jobs and are in business for them- selvesin every state, You-will make good! Start now! Catalog Free! ing actual trouble shooting of makes and models. No Special Schooling Needed —Youlearn | Get my fine 68-page Free Catalog. Shows New preferred opportunitiesopen to you and proofs School Wy Ff eraduates’ success. All Freel Write today! in Cincin- Address School Nearest You HENRY J. RAHE Dept. 2885 Kansas City, Mo. Cincinnati, Ohio easily here. Step, Waltz and latest ‘‘up-to- Peak System of Mail Instruction. New Diagram i music needed; t! uccess absolute! informatio’ WILLIAM CHAND Room 40 4 LER 737 Broadway, , Learn to Dance YoucanlearnFox-Trot,One-Step, Two- * the-minute’’ so- ciety dances in your own home by the wonderful 8 y guaranteed, Write for § aiTerms, Send today for . n 8 ingly low offer. PEAK, M.B Fn ae “4 vein eac i u end “+ the new Mellinger Extra-Ply, fice Seeate ~~ Gic seconde). . Shivoss Pies Ce LINGER TIRE & RUBBER CO. - MELLIN le ME 1004 Oak St., Kansas City, Me. To the Man With an Idea }} I offer a most comprehensive, ex- 7 § 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 tq any expense. Booklet of valuable information and form for property disclosing your idea, free on request. rite today. RICHARD B. OWEN Patent Lawyer 6 Owen Building, Washington,D.C. 2276-D Woolworth Building, New York City se NO FOR Ni THIS FORM DON’T LOSE YOUR RIGHTS TO PATENT PROTECTION Before disclosing your invention to anyone send for blank form *“‘EVIDENC CEPTI E OF CON- ON” to be signed and witnessed. A sample form together with printed instructions will show youjust how to work up your evi- dence and establish thesame before filing ap- plication for patent. As registered patent at- torneys we represent hundreds of inventors 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 sent upon request. Ask for them,—a post card will do. PATENTS AND TRADE MARKS 274 Ouray Bldg. WASHINGTON, D. C. Originators of forms “Evidence of Conception.”

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IF YOU HAVE AN P AT E ye T ty INVENTION and DESIRE 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. t l PEED 605455665050 s 6b bbb dS6 6USESES A OkEE SSE RSS RANDOLPH 9G COQz 0 srnmer...nccccccccccccccccsccsseseseece 130 F St. N. W., Washington, D. C. . a al ee TO LEARN HOW TO prcccococssss----

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.

PATENTS Send us sketch or model for patentabilit upinion and exact cost of patent. Our boo “How to Obtain a Patent” Sent Free on re- quest. It tells how to apply for Patents, Trade Marks, Foreign Patents, Copotiakta, etc.; gives information on Patent Procedure; tells wh should know. Th ds of L clients, are our references. CHANDLEE & CHANDLEE, 25 Years‘ Experience 425 7th St. Washington, D. C.

at every inventor ‘3, who are our

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, IIl. Hobart Bldg., 582 Market Street, San Francisco, Calif.

4 A Hand-Book of Essen- PATENT-SENSE tial Information and Advice relative to Patents, Trade- Marks; Assignment, Sale or Licensing of Rights; Abstracts from Leading Decisions; State Laws on Patent and Trade-Mark Property. FREE! Write LACEY & LACEY Dept. B, Washington, D.C. Established 1869 PATENTS Secured Prompt Service. Avoid dangerous delays. Send for our “Record of Invention” form and Free Book telling How to Obtain a Patent. Send sketch or model for examina- tion. Preliminary advice without charge. Highest references. Write TODAY. J. L. Jackson & Co., 169 Ouray Bldg., Washington. D. C. Free shite onPATENTS < information and advice to inventors on securing Patents. Send model or sketch of your invention for Free Opinion of its patentable nature. Prompt service. ‘20 years experience. Write today. TALBERT & TALBERT 404 TALBERT BLDG.,Washington,D.C. PATENTS TRADE-MARKS COPYRIGHTS Send for our free book of patent information Beale & Park ss5.St<¥titen,2- ¢:

SIXTH EDITION

Popular Science Monthly Fitting a New Top on a Steel Rod Tip _ fears the tip of a wooden rod breaks, it is not difficult to whittle it down and put on a new tip. When a steel rod breaks at the tip, it means a nice job of

y Three stages of mending the tip of a steel fishing-rod are here illustrated soldering and guarding against melting one of the guides, should the rod get too hot. The method I used was to stuff paper in the joint to keep the tip in position, wiring the guide to prevent its coming off. After successfully soldering the tip in, I removed the wire clamps that held the guide.—JAMES M. KANE. Simultaneously Releasing Two Bolts of a Trapdoor ” the accompanying illustration a method is shown of simultaneously releasing the two bolts on a trapdoor so as to permit the door to swing down on its hinges. The mechanism was copied from that of the trapdoor of the old gallows in Bucks

7CAN YOU. think of a simple, practical idea that will fill one of the many ree quests we have on file for new invene tions? It may mean a fortune for you. Thousands of things are needed RiGut 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, t00. A postal will do— SX it is free. PATENTS ADVERTISED For SALE FREE In INVENTION And MANUFACTURING SUPPLEMENT. Published for the man with an idea. INDUSTRIES, INC. Send for free sample 201 Patent Dept., copy. One year’ssub- We help our clients, Without charge, to get the dollars out of their ideas—having facilities none others possess. Advice free. Don't delay—get the , book at once. AMERICAN

WASHINGTON, D. C. i scription 50c.

102

Pull the rope, and the bolts, simul- taneously released, will let the trap- door fall County, Pennsylvania. The lever that pulls back the two bolts resting on cleats in the frame of the door is operated by a rope attached to its free end. Cotter-Pin Holes Found without Loss of Time | O locate cot- ter- pin holes quickly, punch' a small hole on the end of the bolt just over each end of the cotter-hole so that when the holes are hidden from sight when drawing up the machine parts, the punch marks on the end of the bolt will show the di- rection, and the Mark the end of cotter-pin can be’ the bolt to show fitted without loss the place for the of time. cotter-pin

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it Ss

July, 1921 To Dist 5: Sneath Mintek on Aluminum yee tries to put a good finish on the surface of aluminum is prob- ably very much disappointed with the result. The writer offers this suggesticn, feeling that it will be of help. He employed an ordinary block-plane used in the regular manner, just as if a sure face of wood were to be planed. The secret

With an old block-plane and some kerosene, you can give a smooth finish to aluminum is to use kerosene as a lubricant. Plenty of the oil is applied and the plane will work nicely. Of course an old plane should be employed for this work as it does not im- prove the blade.—CARL ROYER. New Type of Oil-Heater for Metal Work HE oil-heater described here was de- signed for use in a railway car-shop. Oil and air are admitted through separate pipes that join a few inches from the i; WIPIPE 25°SLEEVE B WIPIPE CLAMP 2 GLOBE VAWWE he eh

pani’ (O) a ee THREAD

—} Details and dimensions of the oil- heater described are shown here burner. The flow of air and oil is regulated by two °¢-in. globe valves. The burner itself is a tube into one end of which a 3%-in. tube carrying the oil and air is threaded. At the base of the tube a number of airholes are provided. Inside of the burner tube a narrow tube forms a coil shown in detail in one of the illustrations. As will be seen, the flames of the burning oil heat the coil and hence increase the efficiency of the burner. By means of flexible connections the position of the burner may be changed as necessary and the flame may be directed to any point desired.—JosEPH K. Lona.

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PATENTS 2a FREE OPINION AS TO Sent FREE on Request Contains full instructions regarding Patents, Trade-Marks, Foreign Patents. Our » Methods, Terms, and 100 Mechanical Move- ments illustrated and described, Articles on Patent Practice and Procedure, and Law Points for inventors. OUR TRADE MARK BOOK Shows the value and necessity of Trade-Mark Protection and gives information regarding g unfair competition. OUR FOREIGN BOOK We have Direct Agencies in all Foreign Countries. Write for our illustrated Guide

Book on Foreign Patents. SPECIALIZATION Our Staff The field of invention is so vast that it is impossible for any one man to become an expert in all the different classes of invention. Only those practically skilled in the class to which the invention relates are capable of rendering efficient service. For this reason Victor J. Evans & Co. employ a number of patent lawyers and mechanical experts who have been selected for their special knowledge and ability in certain lines of invention. Each case is placed in charge of experts in the classes in which the invention relates. THE VALUE OF YOUR PATENT Will depend much upon the skill and care with which your case is prosecuted in the United States Patent Office. This work will receive the benefit of skill and experi- ence acquired by a long and successful practice. We spare neither time nor pains to secure the broadest possible patents that the inventions will warrant. That every case entrusted to us receives our best efforts, and that our work is done consistently, skillfully and thoroughly is evidenced by the many unsolicited letters of commenda- tion that we receive constantly from our clients. We will furnish upon request lists of clients from any State in the Union for whom we have secured patents. Our New York, Philadelphia, Pittsburgh, Chicago, and San Francisco Offices Owing to the growth of our business we have established for the benefit of our clients Branch Offices in New York City, Philadelphia, Pa., Pittsburgh, Pa., Chicago, Ill., and San Francisco, Cal. These branch offices being located in these large commercial cities, together with our Main Office located near the U. S. Patent office, in Washington, enables us to more promptly handle the business of our clients, particularly as the branch offices are in constant touch with the Main Office and fully equipped to handle patent business in all its branches. : Highest References—Prompt Attention—Reasonable Terms

VICTOR J. EVANS & CO. Patent Attorneys New York Offices Philadelphia Offices Pittsburgh Offices 1007 Woolworth Bldg. 135 S. Broad Street 514 Empire Bldg. Chicago Offices, 1114 Tacoma Bldg. San Francisco Offices, Hobart Bldg. | Main Offices, 760 9th Street, Washington, D.C. Gentlemen: Please send me FREE OF CHARGE your books as described above.

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SP ECIAL OFFE PATENTABLE NATURE Before disclosing an invention, the inventor should write ) for our blank form ‘‘Evidence of Conception.” This should be signed and witnessed and if returned to us to- gether with model or sketch and description of the inven- tion, we will give our opinion as to its patentable nature. Our Three Books Mailed 2 Free to Inventors \ : WY Our Illustrated Guide BOOK Y HOW TOOBTAIN A PATENT i i 3

| ; y '

7,

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ees errant aaa ra 2a eS: AE US aS TUT ibngedinadaaictmneibr smeared = ia. ee ee Sree ot ti ei 1 1 | i Using Bull- Dog Die- — No. i pire sizes \% to 1% Pipe-Threading right and tight the first time STER Bull-Dog Die-Stocks are built for absolute accuracy. You can repeat exactly duplicate threads indefinitely. At the end of each cut the dies open, the tool is lifted off without running back and the turn of one lever resets the dies instantly to exact size. For details, ask your supply house or write The OSTER Manufacturing Company f 2100 East 61st Place, Cleveland, 0.,U.S. A. Are Found Wherever Lathes Are Used Schools and Colleges use them for ia a instruction purposes; Automobile Man- ufacturers, Makers of Small Tools (who require work of minute accuracy), Machine Shops large and small, many other industries, even hotels and de- partment stores, are using Monarch Lathes with universal satisfaction. Monarch Lathes are built with all the latest improvementsand many exclusive features, in many sizes to meet all lathe work requirements —the small shop handling only light work, or the largest shop or plant where the heaviest work is done. Monarch Lathes are reasonably priced within the reach of every prospective purchaser. Write today for catalog and price list. Schools write for our special school proposition The Monarch Machine Tool Co. 116 Oak Street Sidney Ohio WANTED—A Representative in every fac- tory in the United States. Popular Science Monthly, 225 West 39th Street, New York. Providing a Safe Place for the Bicycles HOWN below is an illustration of a rack that I constructed in my garage for the accommodation of several bicycles. It is made of 3%-in. pipe, 31 in. high from the floor to the elbow, and 414 in. from the © aed * eth This shows a safe and reliable method of parking a number of bicycles in the garage wall. : The pipes are placed 2 ft. apart, leaving enough space to prevent the bicycles, resting against the uprights, from becoming scratched or otherwise injured while putting them in or while taking them out.—F. RESCHKE. Emery-Cloth a Substitute for Oilstone A PASSABLE oilstone in emergencies is that made with a piece of fine emery- cloth and a few drops of machine-oil. Lay the strip of emery-cloth on a flat surface, pour on the oil, and rub it over the surface with the finger. Allow the oil to penetrate before using. Finding my- self without an oilstone recently, I employed tlis makeshift and found it satisfac- tory. It is not as economical as ‘the, real accesso- ry, of course. In case of neces- sity, however, it is not a bad substitute.—GEORGE H. HOLDEN. New Uses for the Old Family Nutcracker east well regulated family possesses at least one nutcracker, usually slumbering in a kitchen drawer and resur- rected only during the holiday season. The old nutcracker, however, is not quite so limited in its usefulness as people seem to BLOCK If you have no oil- stone, emery-cloth will do When nuts are not in season, the old nutcracker may be used as a wrench for pipes or nuts think. It can be used to advantage as a small pipe-wrench or for tightening nuts, bolts, gas-jets, etc. The picture illustrates the use of a nutcracker as a _ nut- wrench.—W. A. JACKSON. 104 well — ~Popular Science Monthly To Make an Underground Telegraph Set Tas little equipment can be used to carry on communication without wires over a distance. of 20 or 30 ft., depending upon the power of the induction coil used. It will serve for all practical purposes up to the distance mentioned. Four tin or galvanized-iron plates about 2 ft. square are required. Brass or copper plates would be better but cost much more. A brass rod is soldered to each one of these plates and they are then buried, occupying the positions shown in Fig. 1. If a 1-in. spark-coil is used, the two sets of plates may be placed about 30 ft. apart. The plates of each set are placed about 10 ft. apart. They should be buried in soft, damp earth about 4 ft. deep. When they are put in place, a little salt should be placed over them before the earth is filled in. A bag of charcoal could also be used to n th RECEIVE TRANSMITTE? an 7 ya y WENA \— METAL PLATES” Here the proper method of Fig. 1. placing the metal plates is illustrated advantage, as a little of this material placed about the plates will make possible a much better earth connection. The tops of the brass rods that project from the ground should be threaded to receive a nut. Connections are then made with the instruments inside the house. The receiving apparatus is of the simplest type possible. It is shown in Fig. 2. A telephone inductance coil used in connec- tion with a small telephone receiver com- prises the receiving outfit. The required connections are shown. Every connection should be made as well as possible because very weak currents are used. The transmitting set is also shown in Fig. 2. A spark-coil is used. This may be of any size, the more powerful the better, Fig. 2. The wiring shown here is for a telegraph set with a single receiver and a key at the transmitter end as the signals will be stronger and they may be sent over greater distances. A few dry cells and a key are all that is needed in addition. When the key is pressed at the transmit- ting station, the impulse will be heard in the receiver at the receiving station. If communication is to be carried on, it will be necessary to have a receiver and a trans- mitter at each end.—W. C. ROYER.

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eS ng d. to er al le ct to le ay ry it- in If vill ns- July,'1921 Build a Smokehouse as an Investment ARMERS who keep hogs will find that a smokehouse for curing hams, shoulders, and bacons is a profitable investment. A hillside is the best location. The fire- place, a cubical space 3 ft. long, 3 ft. high, and 3 ft. wide, should be made of cement from 4 to 6 in. thick. An iron door should be provided for introducing the fuel. Near the top of the chamber there should be an opening for a 4-in. smoke-pipe leading up- ward to the smoke-chamber, which on small farms may consist merely of a barrel or hogshead. A perforated cover should be provided for the barrel. The pipe through which the. smoke is conducted from the fire-pit to the curing- house or -barrel may be of cement, stone- ware or terracotta with a diameter of ap- proximately 4 or 5in. The cost of the mate- rial is small and the construction is simple. For fuel, green hickory, maple, or any hard wood should be used; never pinewood Every farmer should build for himself a perforate Top smokehouse similar to this ‘I CEMENT TOP Y rand eae WHESNMG\ 4 a eee ~ ge: UE ae : ? y —= ; SMOKE PIPE: 4 = 4° T.C. PIPE ” i 6'- 0" | HA---FIRE PIT JETT ide-WALL OF STONE. BRICK OR CONCRETE "NGRADE GYIRON FIRE DOOR or any wood that contains resin. The meat should be smoked from 36 to 48 hours, unless it is to be kept a long time, when the smoking should be continued much longer. Using an Old Tire in the Chicken-Yard ELOW is illustrated a method of utilizing an old automobile tire for making a combination chicken-feeder and drinking-pan. The tire should be cut in halves all the way around, one half to form the water-pan, the other the feeding-trough. The water-pan is elevated by resting it on a cylinder of sheet metal. The feeding- trough forms the lower part. A cone of —— SNEET METAL HALF TIRE x FOUR BOARDS EQUALLY SPACED SCREWS SPACE TIRE With a little trouble one of these feeding- and watering-troughs for chickens may be made from an old tire Sheet metal is so arranged that between it and the wall of the supporting cylinder of the water-trough there is room for the grain supply for the chickens. The grain trickles through a narrow slit into the feeding-trough, taking the place of the grain in the trough as it is eaten by the chickens. Four wooden boards, cut to fit the curve of the tire, are placed, equally Spaced in the trough, to give support to ma BrOWNGLSHARPE MAcHINIsTs Tools You will invariably find the modern mechanic in every shop using Brown & Sharpe Ma- chinists’ Tools. He knows that they have won for him the reputation of being one of the best mechanics. The seventy years experience that enters into their manufacture, com- bined with Brown & Sharpe quality are his guarantee that he has obtained the best tools procurable. Send for catalog No. 28 listing over a thousand tools BROWN & SHARPE MBbBc. Co. PROVIDENCE. R.I. the rubber.—C. E. Kin. TOOL CASES EXCEL = eg : Machinists, Tool Makers and y es ’ ‘ Carpenters find them most Concentrated G NT Soft Drink Extracts 29 Get the Money Something new—just out—nothing else like it—Concentrated Soft Drinks—just add sugar and water and serve. Many different kinds—orangeade, wild cherry, grape, etc, Best summer seller ever in- troduced. Everybody, young and old, every home, church fair, picnic, etc., isa sure customer. Hustlers coining money. in : appearance, service and price. Immediate shipment. Booklet describing 20 styles on request. The Pilliod Lumber Co. Dept. A, Swanton, Ohio Sell Our bh (apr , ‘ © One bottle makes 32 glasses. than Icaglass. Guaranteed pure. Small package—carry it right with you. Noex- perience needed—show it—sell it. Act quick—don’t wait—spend one cent and make hundreds—send.a postal TODAY. AMERICAN PRODUCTS COMPANY, 5314 American Bldg. Cincinnati, Ohio ing Fixtures” Ready to hang. Direct from manu- -facturers. Completely wired in- cluding glassware. Send for Catalogue No. 20 ERIE FIXTURE SUPPLY CO. Desk A, Erie, Pa. ONE MAN SAWS 40 CORDS svoetton A DAY! Write today for Special Low Factory Price and Big FREE Book on OTTAWA Log Saw. Does 10 to 15 men’s work Friction Clutch lets you stop and start saw with engine never stopping. Strictly aOne Man Outfit. Mounted on wheels. Runs belt machinery when not sawing. Over4@ H-P. 310 Saw Cuts a Minute! 30 Days’ Trial. Cash or Easy Payments. 10-Year Guarantee. Special Offer Now! Free Book! Send Today! OTTAWA MFG. CO., 190) Wines atone $100 TO $200 A WEEK is the money that dozens of our men are making right NOW! We can put you in their class in a few weeks’ time—make you your own boss—and show you how to earn more money than you ever made before. Here's the secret: BE A TIRE MAN Get into this big-money game with an Adams- Barre Machine. You can do everything from vulcanizing to retreading and rebuilding old tires and making them as good as new. oot lessons by me of o Heres h soume at one | our fully equipped schools. work can be guaran- ase teed. Write us now for fuil details. nent The Adams-Barre Co., 1244 N. High St., Columbus, 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 105

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sas FT — Soeur pene natant = pers eS TAS LE AE, PETE CES ARNT LE NED IS RET CEI IT IS see ers SE SE I A EACLE TEE PAK EES: | a _ " ; rT | ~ @é ya \"'s STANLE HAMMERS are friends of more real mechanics than any tool in the world TOI vy) ND a Stanley Hammer usually identifies its owner as one who takes pride and interest in his work. Go into your hardware dealer’s today and feel the comfortable grip of a Stanley Hammer. You'll start your Stanley Tool collection right then and there. Send for booklet 5-G Tre Stancey Ruce& Lever Pant THE STANLEY Works New Britain, Conn. U.S.A. WEALTH, HONOR, RICHES Do not depend upon opportunity or intellectual brilliancy of any kind, because it is well known that uneducated people often acquire great wealth, while cultured and talented people remain in poverty. Again, they do not depend upon capital, because many men with capital lose what they have, while others with no capital acquire phenomenal wealth. Law governs every form of light, heat, sound and energy. Law governs every material thing and every immaterial thought. Law covers the earth with beauty and fills it with bounty. Shall we then not be certain that it also governs the distribution of this bounty ? We have published a remarkable little book, giving the conclusions of science concerning these laws, which we will send _for only 10 cents. Master Key Institute, 258 Howard Bldg., St. Louis, Mo. mei FAC / \ zaeee F model comerien. BS, Cole Tis Sa lf .: oe ‘amous aid, FOR i! Wh: \YS TRIAL. Select biescle and KN a eult—cash or eqsy payments. and iN be “a: ives cau x otrat belt tees Va i¢ an PS \ ND NO _ REE Ranger Uatatee ood A ha EF terms. Mead ees chit agar a: — This Coaster Generates Its Own Light HE drawing gives a fair idea of the manner in which a coaster is rigged to supply a light when speeding over the side- walk. A small electric dynamo of 4- or 6- volt capacity is secured by screws to the rear end of the body so that its pulley will When the coaster is running it gener- ates its own electric light be in line with a drive pulley that you will clamp to one of the rear wheels. This drive pulley should be 6 in. in diameter and may be sawed from !4-in. lumber with a sharp compass saw. The hole in the center of this pulley will need to be sawed out large enough so that it will slip on the hub and four 14-in. clamp-bolts should be used to secure it to four spokes of the rear wheel. The circumference of this pulley must be grooved with a jackknife so that it will hold the cord belt con- necting it with the pulley of the generator. On the front —=O == of the coaster a Wy small 4- or 6-volt ‘ane SEZ electric lamp should be secur- ed with two screws to corre- spond with the voltage of the generator. VAY Showing how the dynamo is hitched to the wheel of it.—F. E. BRIMMER. Boot Protector for the Man Who Digs ween digging, the novice often finds that the spade hurts his foot and also does damage to his sole. This may be pre- vented by the use of a protector. A piece of wood is cut to fit the instep of the boot. To this is nailed a strip of canvas or burlap long enough to come up round the sides of the boot. At the ends of the ma- terial are fixed tapes by means of which the burlap is tied into position. On the face of the protector (the part that will come in contact with the spade) a piece of tin is nailed. The wood protects the sole from the edge of the spade 106 DYNAMO This lamp should be placed a little to the right or left of center so that the steering handle of the coaster will not be right in front Popular Science Monthly Mechanical Drawing Instruments Pree Pp G.OO Prepaid . See — ae rsa ieee Write for free Booklet. GOLDEN GATE COMPANY 4331 North Oakley Ave., - = - Chicago, III. ALIN This is an opportunity of a life-time to build up an automobile business of your own. Exclusive territory, no investment required. Write today without fail. ae! LKUUUUUUUNUUAN AAA $372 in 17 Days Mr. C. J. Weeks, 2319 Lydia Ave., Jacksonville, Fla., easily made this money by selling Sparko-Gaps! $100:in Less Than One Week Irving Laighton, Vineland, N.J., reaped this harvest by _ selling Sparko-Gaps! George A. Norton, of Vernon, N. Y., earns big Mr. E. Schuster, of Brooklyn, N. Y., sold eight the first day. SPARKO-GAP Government-Approved) This is what it is and what it does, A tiny device that you fasten to the top of the spark plug. Itincreases engine efficiency 37 per cent. The only device to intensify spark. Approved by the United States Government. Thousands of Sparko-Gaps being sold every day. Large guaranteed profits. SPARKO-GAP CO. Remy PONY: IAL cooking in summer a shoveling -- carrying c in use over 10 zeore, in fire box, easi lifetime. Makes its ow: money-back itee--30- AGENTS WANTED. THE OLIVER OIL-GAS BURNER Makes pleasure yeu want it—not a minute longer than you need it. Does away with coal and wood—cheaper. Makes your stove or range a gas stove. No fires to make. No ashes, dirt, smoke, odor, chopp' oal or wood. Makes your stove bake better, cleaner, quicker. Thou n’t c lipped in or out, absolutely safe. its sow n gas from coal-oil (kerosene) at small cost. Gives even heat instan’ rms tly, turning valve. Saves money, time, | by simply FREE literature and special introductory price. BIG MONEY. Oliver Oil-Gas Burner & Machine Ce., gest Mfr's Oil Oldest Larg r -Gas Burners. 2007-G PINE STREET, ST, LOUIS, MO. In Your Stove instead of a task. Heat when Saves hours of a 3 sands ange your stove, just sits rn. der for nished, all parts cut to exact fit. ny one ca’ board, upholsteri The Central Auto Supply Co. Only $45.00 For This Job Complete may can plet assemble this job. Complete with hood, radiator shell, instrument 0 ng. me’ parts, wood parts, bolt screws, etc. Fiat radiator shell furnished made up. Designed low with lack of wind resistance. Price set up $90, “Re ~ Not Paper Patterns il Parts Complete e ther particulars on request. Eng. Dept. 122 Louisville, Ky. these instruments. rite today and our FREE OFFER. Address:— MODERN PHONOGRAPH SUPPLY CO. 313 So. Clinton St. Build This Phonograph Yoursell ~ TREMENDOUS SAVING IN COST Easy, fascinating work, with our SIMPLIFIED PLANS. We furnish blue prints, di 5 it wo Chicaco, itt. the name, year and m our catal You Can Save *50.00 We mgke these recovers to fit $6 55 all makes and models of cars. be Any person that can drivea and up Parcels Post Paid ters sewed together with rear curtain, fasteners, welts and tacks. All complete. Give us el number of your car and we will send you and quote you exact price. ¢ with 1 LIBERTY TOP & TIRE CO. Dept. E8, Cincinnati, O. By recovering your old auto top frame yourself. car can put iton. We furnish instructions, Roof and quar- ‘BOWLEGSaniKNOCK-KNEES’ ma UNSIGHTLY == Wh 5 SEND FOR BOOKLET SHOWING PHOTOS OF MEN WITH AND WITHOUT The Perfect Leg Forms ¢ PERFECT SALES CO.,140 W.Mayfield Ave., Dept. 45, Chicago, Ii.

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2 a Ren: FF RSW — r- aa July, 1921 Active Boys Will Like This Toy Mp ZY Little boys are fond of running and this toy lends additional zest to exercise F you have a little boy not older than five or six years, you can give him great pleasure and welcome exercise by building a push-wheel like that illustrated here. The construction of the toy is made so clear by the illustration that no further description is necessary.—EMILE LE BEL. Keep Your Golf-Balls Clean and Dry HEN the holes in a golf-course are full of water after a rain, a piece of wood, a staple, and a piece of string are all that is needed for making a simple device to keep the ‘“‘holed’”’ golf-balls clean and dry. The next time you go to the golf-course, take a small ruler with you and measure the diameter of the holes. Mark off a circle on a piece of wood, using half the Fastidious golfers should carry one of these ball-protectors in their bag for use after a rain width of the hole as the radius. The wood can then be sawed round with a hacksaw, following the line made by the compass. It would be well to saw inside the line, as the piece of wood must fit the hole loosely. Drive a small staple into the center of the wood, and attach a string to it. When your ball is near the hole, and you expect to put it in on the next shot, lower the piece of wood into the hole. The ball can be taken from the hole by pull- ing out the piece of wood by means of 1/7, HP Motors $13.50 We offer 3000 quarter Horse Power ALTER- NATING CURRENT MOTORS of the very latest type, 110 volt, 1740 RPM, 60 Cycle single phase at $13.50 each FOB Chicago. May be attached to any light circuit in the home or power circuit in the factory. Remarkably simple in design and sturdy in construction. Fan-cooling ventilation system prevents overheating. These motors carry the Manufacturers ONE YEAR GUARANTEE against mechanical defects and are shipped to purchaser, ready for use in original container just as received from factory. Satisfactory performance guaran- teed, or money refunded. AT THIS EXCEEDINGLY LOW PRICE CASH MUST ACCOMPANY ORDER, SPECIAL PRICE ON THREE OR MORE MOTORS OF $13.00 EACH. These Motors are Ideal for use in the home on washing or ironing machines, or on the bench; in the garage or machine shop or any place where one can be used. They are quiet cool running, efficient and practical —with a very small chance of getting out of order. OUR SUPPLY AT THIS PRICE IS LIMITED TO THE ABOVE NUMBER GET YOURS BY SENDING IN ORDER NOW. Single terminal—with cord and plug—Non- Reversible. Double terminal—can be reversed from out- side — cord and plug not furnished. Northwestern Electric Company 410-420 So. Hoyne Ave., Chicago, Illinois the string. ARTHUR GOLDENBAUM. AGENTS—SALESMEN —SALES MANAGERS EXCLUSIVE TERRITORY ON NEW INVENTION Will you listen when opportunity knocks? Fortunes have been made in new automobile inventions. Grab this one quick. Your minutes are like dollars—don’t waste them now. Read—investigate—then act. The Speederator for Ford cars is a new inven- tion that makes any Ford run like a Packard. Stops stalling—bucking and motor racing. Gives a smoothness to Ford driving that is wonderful. And just think— Speederator is put on without boring holes or special tools of any kind. Any Ford driver can put one on complete in twenty minutes. Never wears out—never needs attention—operates automatically. Sells like lightning. Old Ford drivers say best and only necessary Ford part. Get full information. This is not a ready made fortune but it is the opportunity to secure the exclusive sales agency for this new invention. Don’t take our word—get the proofs. Just be honest with ‘yourself and investigate. Let the money you make talk from now on. Smashing records of success will show the way; Helton, Utah, sold six hundred in five weeks—profit $1,800.00. Crist, N. Y., sold 23 first day—said would have sold more if he had had them—now averages more than 400 a month—profit, $1,200.00. McAllister, Ills., say, sold four first afternoom. He is now using 100 a week. These straight-from-the-shoulder-facts point the way. Hoover down in Ohio sold 29 in one day, profit $87.00. Benke, Mo., averages 200 a month. Campbell, Tenn., 1,000 a month. Crandall, Iowa, put on thirty sub-agents in one week. Dryden, Calif., sold 150 in ten days. Grace, Hawaii Island, 200 in two weeks. Teeters, Mich., first three dozen in ten days. We say you can make $55.00 TO $300.00 WEEKLY selling the Speederator. Best article to advertise itself you ever saw. Once on a car the driver will never let you take it off. Sales are made fast and furious. Boyer, Penna., made $72 first day. Cook, N. Dak., 150 sold first two weeks. Cahan, Ariz., 72 in two weeks—$216.00 ear. Join the ranks of successful men in this work. NO EXPERIENCE NECESSARY t ~ ~ show us that you mean business and are ready for usiness and we will show you how. But first, make ais prove these facts. We have nothing to apologize for. The Speederator is a grand success—you can make money fast if you have the territory—so get busy now. Write to-day for the necessary information and see for yourself. Don’t delay—plenty of good territ left—if you area hustler you can have money in the ban THE GREATEST FORD INVENTION _inafew weeks. Just write—now—to THE PERRIN METAL PARTS CO. 1098 Hayward Building, Detroit, Michigan 107

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LE Se LS SEAS ES AT LL TIS TTS ETI NS TE A TR EET ST TNT TEER NT ee ee ae et Alte 5 aS: ge ee ie, oo. 6 home ANNA This shows the handiest way to find revolutions- per-minute of a shaft or fAlywheel—using a RAO SPEED COUNTER Hold the Speed Counter light- ly against end of revolving shaft; the spindle of the instru- ment will turn freely, allowing you to deliberately center point of counter on revolving shaft. When the second hand of your watch comes to0, press on the end of the counter and it will instantly begin to count. At the end of the minute remove pressure and the count stops instantly—the register is auto- matically disengaged by a spring clutch—giving you the exact R. P. M. without man- ipulating with a_ stop-watch. (Cut less than 14 size.) The Veeder Speed Counter enables you to keep motors, engines, gen- erators, line shafting or machines operating at efficient speeds. Price, with two rubber tips (as il- lustrated) $3.50. Ask for the Veeder booklet, showing production counters, hand tally count- ers, speed counters and other count- ing mechanisms. The Veeder Mfg. Co., 44 Sargeant St., Hartford, Conn. Giving Greater Leverage to the Socket Wrench HEN socket wrenches of the brace type are to be used in a shop for tightening or loosening large nuts or bolts, it is sometimes desirable to increase their } EXTENSIONS , RIVET PIPE RiveT By lengthening the arms of the wrench, greater leverage is obtained for turning large nuts leverage. The illustration shows how such increased leverage was obtained in a repair-shop. The two parallel arms of the brace were cut as shown and the severed. parts united by pieces of iron pipe driven on the severed stumps and held in place by rivets. For Homemade Toys Use This Wood-Saw Se farmer toys at home, I had a great deal of woodcutting to do. As I did not wish to purchase a bandsaw, I rigged up an old sewing-machine as shown in the BEARING SAW_& SPIND WOODEN LE ODEN PULLEY With the aid of an old sewing-machine stand you can easily rig up a service- able circular saw illustration. A block was attached under- neath the table to support the spindle screw, which is shown in detail. A wooden pulley, forced on the spindle, is connected by a belt with the wheel of the sewing-machine. The spindle carrying the circular saw was made of part of an auto- mobile axle.—J. H. MOORE. A Cotter-Pin Extractor from an Old File BY following the suggestions given in the illustration, a useful cotter-pin ex- tractor may be made from an old file at a trifling cost. Bend the tang of the file in the form of a hook, then heat the other end of the file to red heat and bend it as shown by blows with a hammer. HEATED _— AND BENT If this tool will not extract a refractory cotter-pin, it will take dynamite to dislodge it 108 Popular ®cience Monthly This warn e0-Day Test—Lifetime Guarantee zodneation all other sizes—3, 4, 6,8, 12,16, 22 Big Ton P. You buy direct, C Cash oreasy p pay- ments. 4 oth. bonds face value. Any sizeor style outfit you want. Big Engine Book, FREE. WITTE ENGINE WORKS 2227 Oakland Ave.. Kansas City, Mo. 2227 Empire Bldg., Pittsburgh, Pa. BE YOUR OWN BOSS. MAKE MORE MONEY With little capital, you can establish a business in your own home town and make $10 to $30 per day with Anderson’s Steam Vulcanizers. Better work, less cost and bigger profits. There are Poasraon schools in 84 states, one is near you, Better ehootineg plus finest equipment makes Anderson tireologists successful. We teach you the famous An- derson method of vulcanizing and the operation of t derson Super-Heated Steam Vulcanizer and Retreader. Takes 6 to 10 days in school und costs $35. If at any time bh buy an Anderson Vulcan- zer, we refund your $35 and ‘ pay you $5 per day for each of the 10 school days, because we sell the work you do. We will tell you how to make money, rite today. ANDERSON STEAM VULCAIZER co. 101 Williams Bldg. Indianapolis, Ind. NEW MOTORS ‘scr STANDARD MANUFAGTURERS PROMPT DELIVERY ALL SIZES UP TO SH-.P. We Specia'ize In Small Motors & Generators ALL PHASES AND FREQUENCIES IN STOCK AT ALL TIMES Largest exclusive Mail Order Small Motordealers in the world. CHAS. H. JOHNSTON, Box HL). West End, Pittsburgh,Pa. J Prveonsn” 1750 R.RM. P: Pe H nD 7B / ; JS Special Quantity Prices: Write For Catalog. TO FORD, OVERLAND 4, CHEVROLET POWER-SPEED 490, and DODGE OWNERS ae The most complete and instructive peek ever published on Prolenging the Life Increasing the Power, Speed, and En- durance of automobile motors. Explains where aeroplane and racing motors get eir amazing power, and tells how the power of the above motors may creased tremendously. Whether you drive a Passenger car, Truck, or are a **Speed Demon’’ you will find ‘this book intensly interesting. Also contains use ful tables and data. Free fo ort ing. TTAWA TAWA of eS devel you og ee any cueing. Ottawa, Kansas. Write today. OTTAWA 951 King Street, Ottawa, =F i N Made in many styles, protect tools for Machinists, Tool Makers, Car- penters, Electricians, Plumbers, . and Auto Mechanics. Request « wales —price—name of dealer | and * faction or Money-Back’ UNION TOOL CHEST CO., 4 22 Mill Street, Rochester, N. Y. s Mechanical Drawing Instruments Be prosperous and successful—Create your own ideas and inventions. Get one of these splendid outfits of drawing instruments at less than cost. 100 complete sets will be offered only—our chal- lenge offer is ready for you now, Don’t Miss It— write to-day for attractively illustrated particulars— FREE. NATIONAL INSTRUMENT COMPANY 4518 North Lawndale Avenue, Chicago, Ill.

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TO OM a July, 1921 A Coil-Spring Winder of Simple Design A SPRING winder of simple construc- tion and which will wind a spring the length desired is illustrated below. The outside shell is a piece of smooth- bore pipe twice as long as the spring is to be and with an inside diameter equal to the outside diameter of the spring. The winding-rod is of solid steel, the diameter of which is the inside diameter of the spring. In other words, the space between the rod and the inside of the shell is equal to the thickness of the spring wire. Cut a slot in the sheil as shown—its dis- tance from one end being equal to the intended length of the spring. Then, drill a small hole in the rod to meet the slot [ HANOLE qr | SPRING LENGTH IRON ROD Coil-springs can be wound with speed and precision with a homemade winder when the rod is inserted in the shell. Pro- vide a thread on the end of the projecting portion of the rod to which may be attached a crank or power pulley. Insert the wire through the slot and into the hole in the rod. Then turn the rod, pressing it lightly toward the back of the shell. The wire will turn on the rod and be carried back uniformly until the hole in the rod, carrying the wire, emerges from the rear of the shell. Then the wire is snipped at both ends and the spring is finished. Using a Mirror to See Who Is at the Door . average housewife does not like to open the door to book-agents, peddlers, or beggars. It is often a great convenience to know who is at the door. By the use of a little mirror arranged at an angle of 45 [nnocenmmnenanincmras a wih Aue . a WB \ To the busy housewife this telltale mirror is a boon degrees outside the window, this is made possible in many cases. It all depends where the door is located. If it is at the side of the house, this mirror may be placed outside the kitchen window. Any one at the door will be plainly visible in the mirror, while the person on the inside cannot be seen from outside. AQ Years of Progress with Fine Tools Use Starrett 20 years ahead of wireless-- In 1880, Starrett Tools were first made. Ma- chinists had been using them for twenty years when Marcon flashed his first message through the air. Because of their unvarying accuracy, Starrett Tools have had a big share in the development of the wire- less. Machinists who build the great engines and dynamos for the big overseas wireless stations, have learned through constant use that Starrett Tools are always right. Forty years’ experience in making fine tools and an unchanging standard of quality and precision—that’s what you get when you buy a Starrett Tool. The Starrett Catalog No. 22 “W” shows 2100 fine tools. Write for a free copy. THE L. S. STARRETT COMPANY The World's Greatest Toolmakers Manufacturers of Hack Saws Unexcelled ATHOL, MASS. CONCRETE ON THE FARM AND IN THE SHOP This new book illustrates and describes in plain simple language many of the numerous appliances of concrete within the range of the home worker. Price, postpaid, $1.00 BOOK DEPARTMENT, POPULAR SCIENCE MONTHLY 225 West 39th Street, New York THE REAL ESTATE EDUCATOR. This book gives a most comprehensive yet most concise arrangement of useful facts about buying, selling, leasing and sub-letting of Real Estate, contracting for erection or repairs, mort- gaging, transferring, insuring, etc. Cloth, 256 pages. Price, $2.00, Postpaid. Cold Pipe Bending Machines Standard of the World Bends all sizes Pipe from in. to 8 in. and or mo- tor operated. Models E&F i Send for Catalog Standard Pipe Bends 1” to 6” pipe, in stock for immediate delivery. AMERICAN PIPE BENDING MACHINE CO. 51 Pearl Street BOSTON, MASS. STEEL SCALES WOOD RULES. RELIABLE ASK YOUR DEALER Send to us for Catalog No, 12 rms urn pote CONG SAGINAW, MICH. How to Run a Lathe An 80- page book for 10¢ Postpaid, Coin or Stamps. 9” Lathe..... 11” Lathe..... SOUTH BEND LATHES For the Machine and Repair Shop REDUCED PRICES ote cee $215.00 | 13” Lathe............$365.00 wo aiewtntacy $275.00 | 15” Lathe............ $450.00 16” Lathe............ $525.00 South Bend Lathes are made in eight sizes, 9-in. to 24-in. swing inclusive. Established 1906 SOUTH BEND LATHE WORKS 433 MADISON STREET, SOUTH BEND, IND. Free Catalog

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——_—= = “Red Devil’’ Pliers made in 100 styles -one for every need. Known and used throughout the world. Style 1024~6% inch shown here. From dealers or from us, $1.25. Red Devil Corrugated Lock Washers Stay Tight! 4 Six points of contact, which means no vibration, no rattling under the hardest service. Re- duce wear and tear, insure longer life and greater safety to parts where applied. It requires 114 turns to loosen them, while others loosen with a 34 turn. ‘Red Devil’? Lock Washers have 662% greater efficiency. Hold on like grim, death. Used wherever nuts and bolts are subject to vibration—on auto- mobiles, trucks, tractors, station- ary engines; marine engines, lighting sets, wind mills and all farm implements and machinery. Made of manganese steel, oil- tempered. Put up in bags in assorted sizes from 3/16” to 5%”, in the following quantities: 30 in a bag, 15c; 60 in a bag, 20c; 90 in a bag, 25c. From dealers or from us. The Mechanics’ Tool Booklet is yours for the asking SMITH & HEMENWAY CO., Inc. Manufacturers of **‘Red Devil’’ Tools 264 Broadway, New York, N. Y. “Red Devil’? Glass Cutters — the glaziers’ standard tools of the world. ‘‘It’s all in the wheel.”” Made in 40 styles— one quality. No. 024 shown here, from dealers or from us, 20c. A Powderless but Not Noiseless Cannon A SIMPLE, safe, and inexpensive toy cannon is made as follows: Plug one end of a length of gas-pipe and screw a spark-plug either through this plug or near it. On top, near the plugged end, screw in a priming-cup similar to those sometimes used on balky gasoline engines. To use the cannon, pour a little gasoline into the barrel (the exact amount will de- pend on the size of barrel, etc.), close the This cannon will provide enough noise and excitement for a safe and sane Fourth of July cup, and ram your load into the muzzle. Now, if the mixture is right, all you have to do is to connect the spark-plug with an induction coil or other source of high potential current, and the shot will be fired.—G. G. STEVENSON. Slow Developing of Films for Amateurs end * good results can be obtained with cut films in plate-holders by the follow- ing slow developing method. Use a weak bath and hang the film at the side of a glass jar by means of a spring clip, with the gel- atin side out, using, say, two films for a jar. With three jars in a_ light-tight box, and holding six films, the lat- ter can be put in place in the morning, and four hours later, or at noon, they will be found developed, and can then be put in the fixing-bath, while six more films are placed in the jars to be removed late in the afternoon. The operation can be repeated during the evening, and as many as 18 films a day can be thus treated. A diamidophenol developer is used, with 10 per cent bromide. The use of the jars make the films curl, but they will soon re- sume the flat shape.— FRANCIS P. MANN. SPRING CLIP Try this method for developing cut films Sediment Cleaned from a Water-Jacket OMETIMES motor-boat engines and even stationary engines collect sand or sediment in the water jackets through the circulating pump. In time the cooling of the engine is impeded and serious over- heating may result. One way to remove any such collected sediment is as follows. In the outlet pipe, close to the cylinder 110 Popular Science Monthly head, imsert a shut-off valve. Then at the lowest point of the water-jacket drill and tap a hole for a fairly large petcock. During normal running the shut-off valve in the outlet pipe is kept open and the petcock is kept closed. When suspi- cious of a deposit of sediment in the water-jacket, COCK INTAKE start the engine a ee and open the ment out of the petcock. Then, water-jacket and not until then, close the shut-off valve in the outlet pipe. This forces the cooling water around and around in the jacket and thoroughly flushes out any collection that may have occurred. When the water is clear, upen the shut-off in the outlet first, then shut the petcock. Be careful not to shut the petcock before opening the outlet, other- wise the pump might create sufficient pressure to crack the water-jacket and ruin it.—L. B. ROBBINS. VALVE IN WATER Use This Special Screwdriver for Close Places SCREWDRIVER that was made for the purpose of removing electric con- tacts from coils and switches under the cowl- board of an automobile is shown in the HEXAGONAL accompanying il- APERTURE Y KNURLED, /ustration. Oppo- site thescrewdriver on the handle is a hexagonal open- ing for loosening the small terminal nuts. As is shown, this tool consists of a knurled disk with a short screw- driver blade riv- eted into the disk. This tool is suit- able for places in which the screwdriver with a long handle cannot be used. The knurled face affords a good grip for tightening or loosening a screw.—G. A. LUERS. For close-range work this screw- driver is very useful How to Prevent Meat from Being Scorched HEN meat has to be boiled for a long time, it often happens that the water boils away and the part of the meat touch- ing the pot is scorched. This can be pre- vented by the Oe en eee ee — a | . use of theshield ‘ ~— A i illustrated here. ¢ fe “at | It is simply a See oe disk of tin or agateware with three or four little feet that raise it about 14 in. from the bot- tom of the pot. The disk should loosely fit the pot, and should have a number of holes for the circulation of the boiling water. The perforated plate will prevent meat from scorching

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t n it e [- it id or n- vl- he il- yer sa on - ing nal m, ists isk 2W- ‘iv- isk. nit- in idle rds ga ite at ad July, 1921 Heavy Dumb-Bells Built of Pipe Fittings DUMB-BELL of variable weight for heavy-weight lifting can be con- structed of pipe fittings by any one with a mechanical turn of mind. No dimensions are given, as the length of the handle and size of the bells will vary. The handle is of 1-in. iron piping of the desired length. This must be threaded at each end for nearly the length of the bell. First, serew on a locknut to the end of the thread. Next comes a pipe-cap of large size. Into this fit a piece of large pipe about a foot long. A second locknut holds that in fixed position. Slip a loose-fitting FILLING HOLE aerate a H J RETAINING DISK LARGE DIAMETER AND LOCK NUT PIPE ) CAP Athletes in training for a systematic development should try dumb-bells like these disk over the threaded end of the handle pipe and thread on a third locknut back of that. The barrel is then completed by fitting on a second cap. This construction is shown in detail. There are,. of course, two such bells, one at each end of the bar. When the dumb-bell is fully assembled, drill a 14-in. hole in the barrel cf each, and close it with a wooden plug. As the athlete increases in strength he may in- crease the weight of the dumb-bell by tak- ing out the plugs and inserting BB shot. When enough have been inserted, screw down the disks upon the shot. Holding Round-Headed Bolts while Cutting Threads c iperhaped in the accompanying illustra- tion is a device that is used for holding 34 by 214 in. countersunk head-bolts while the thread is being cut in the bolt-cutter. The holder is made of machine steel, case- RING OR PIN This jig is valuable in shops where round-headed bolts are threaded hardened, and is securely clamped in the jaws of the bolt-cutter with the slot in a vertical position, and extending ahead of the jaws. A bolt is then inserted into the slot, either from top or the bottom, and pushed forward into the countersink. The hardened key is then placed into the slot until its ring or pin rests on the holder. This brings the knife edge of the key into line with the bolthead. The screw at the rear is then tightened, causing the knife edge of the key to sink into the head of the bolt and preventing it from turning. To remove the bolt, the screw is loosened and the key lifted out; when the bolt is pushed back, it will drop out. grade of special steel; absolutely dependable. ‘“Vulcan”’ Heavy Service C Clamp 34 to 12-14” capacities . “Asgrippa’”’ Medium Service C Clamps 4 to 18” capacities “Light Service’’ C Clamps 2 to 12” capacities BROOKLYN 7 Richards St. CLAMPS that CLAMP ILLIAMS’ lines of Superior Clamps for every purpose are drop-forged from a tough, strong all are heat-treated after forging to increase their stiffness and strength. There is no guesswork whatever about their quality. All tools bearing Williams’ At your dealer's: ask for Machinists’ Tools Book DROP —FORGINGS. «i often cheaper than castings — always far superior — J. H. WILLIAMS & CO. “The Drop-Forging Peaple’’ BUFFALO 7 Vulcan St. St. Catharines, Ontario trade mark, @, are ‘Vulcan”’ Tool Makers C Clamps 1 to 4” capacities ‘“Vulcan”’ Machinists’ Clamps 114 to 414” capacities ‘Vulcan”’ Strap Clamps, 6 styles for planer, lathe, shaper, etc. CHICAGO 1007 W. 120 St. Descriptive Astronomy By E. M. Moulton. A study of the earth, sun, moon, and stars, with a simple explanation of the principles of astronomy. Price, postpaid, $2.6 Popular Science Monthly, 225 West 39th Street, New York City AN EASY WAY TO MAKE MONEY 22: on 48 small salary. Be Sadependens._ Go Go in aed A, rr: pairing business. aie man cove made $60.00 the first ay.”’ Others a > See Se $500 month. Very little Say necded. "Tas plentiful, “Ev aygeeetes @ pos- sible customer. No experience need e@ teach~you. SRALER Tire Repair Gul can’t undercure or oe a no wa FREE Book **How to O Tire sl I ‘el how to make — "tdelay. Write quick. C. A. SHALER co. 2106 Fourth St. Weupun, Wisconsin lll The Boy Craftsman Tells how to design and make many useful things. suggestions for indoor and outdoor pastimes. Price, postpaid, $2.65. Popular Science Monthly, 225 West 39th Street, New York City Gibson lnstruments Mandolin, Mandola, Mando - Celle, , Tenor-Banjo, itandolin - Banjo, Cello-Banjo, Guitar-Banjo, Marp- Guitar, Mando-Bass Many e ‘ .\> Easy to Play Easy to Pay LaSY [0 Pay Select your Gibson now. You can soon be playing the music of the day. Your friends will be surprised and delight- fully entertained. Let us help you organize a Gibson Orchestra in your community. You can in- crease your popularity, income and pleasure by playing for Concerts, Enter- tainments, Charch’/ Affairs, etc. A small down payment and then $5 a month will soon pay for a Gibson and will fur- nish you with wholesome, year-’round entertainment. If you have an old instrument, w® will make liberal allow. ance on a Gibson. Write Today for + fase Book, Catalog, Free Trial Offer, information about Wm. Place, Jr. Book and the instrument you prefer. GIBSON MANDOLIN-GUITAR O00. 487 Parsons &t., Kalamazoo, Mich., U. 8. A. eevee . eee ee

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mb NLY., The Kodak ¥ i 2) Y x 8 ee so = cS . E o ~ a 3 os Fa SSE See -£__- SET Up ane REE a EEE AE — wr * gy gree te er ee oe mae Came att