Popular Science Monthly 1921-05: Vol 98 Iss 5

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TECHNOLOGY copy Popular Science Monthly May, 1921; Vol. 98, No. 5 25 Cents a Copy; $3 a Year Waldemar Kaempffert, Editor Published in New York City at 225 West Thirty-ninth Street 4a Stunting as a Profession Would you do the things described in this article? ARK CAMPBELL, the aero- M bat, and I were seated at the * roof’s edge of a new twelve- story building in lower Broadway, Los Angeles. From our position we could see the swirling mass of people on the ground below. Since early morning they had been there, gazing upward and waiting, waiting patiently for the airplane behind us to slip off to safety—or death. Frank Clarke, the stunt pilot who was going to fly the airplane, strode over. Briefly he stood beside us, glowering down at the sea of upturned faces, then turned back to his airplane, where a mechanic was warming up the engine. The crowd below awoke to the fact that their long wait was about to be rewarded. Arms pointed upward to where the wing projected over the street. “Cameras ready?” shouted the mo- tion-picture director through his mega- phone. “All ready, sir!’’ came the response. The dirigible overhead gave a slight dip to signify that the cameraman aboard her was also in readiness. Clarke, jumping into the pilot’s seat, ran up his engine to make sure that it was mechanically perfect, then pulled shut the throttle. The f 20 FT. GROUND Follow the arrow from A to F; that’s how the airplane accomplishes a stunt landing known as the ‘whip: stall’ By Fred Gilman Jopp mechanic kicked out the chocks be- neath the wheels and leaped back to safety. “‘Ready — cameras!”’ director. The dull, droning hum mounted, rose, grew rapidly in volume and power; the tail snapped into the air; and the airplane rolled quickly along the ninety-foot wooden runway. Thirty feet from the edge of the building, the wheels rose free of the roof; then, with a sharp jump upward, the air- plane took the air like a bird. Soaring easily aloft, it banked sharply to the right, zoomed over a near-by tower, roared the and was off to the hangars with the grace of a bird. Others may flirt with death by climbing about an airplane in mid-air, but Campbell jumps for an airplane in flight. True, he uses a parachute, but his stunt is hardly less perilous because of that. When less than 175 feet from the ground, he climbs back upon the tail, casts his parachute into the air, and lets go. The parachute that he uses is one of the best in the world, and the United States army has contracted for the entire output of the factory. It is || Campbell stands on the train going at eighty-five miles an hour, and Clarke flies above him, trailing a ladder, and then Campbell grabs the ladder 21

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—__—_ Campbell weighs 175 pounds; thus when he crawls out on the end of the wings, great skill on the part of the pilot is needed in order to balance the plane strapped on his back in a small pack. A pull of the cord on his left shoulder releases a small ‘‘chute,’’ which in turn pulls out the large para- chute. Campbell is also the only man, living or dead, who has ever jumped from an airplane to a train and back again. “T did this stunt in. Califor- nia,” he says. ‘‘The train and airplane were both making a speed of eighty-five miles an hour, and I made both jumps to and from the plane to the train by means of a rope ladder and nerve.” Recently Campbell was doubling for a motion-picture in which he had to fight another man on the wings two thousand feet in the air. His opponent, striving. to make the fight realistic, struck Campbell with an _ honest-to-goodness monkey-wrench harder than he intended, knocking him senseless from the wings. He fell one thousand feet before Popular Science Monthly This loss was caused by an accident in which he attempted to turn a full loop under a trolley wire. A guide wire to the trolley pole tore off the left wings yet he managed to jockey his airplan« into a vacant lot before it crashed and dislocated his shoulder. Thus, you see, his title of “flying fool’ is wel earned. He is the first pilot to leave the cockpit with a man on one wing and to work back upon the tail to fly the airplane by operating the rudder with his feet and ‘‘flipping’’ the contro] wires by hand. He isthe originator of airplane changing without a ladder, and claims the only tail-spin in history coming down tail first. Carrying two men on the right wing is his latest stunt. And now both Campbell and Clarke are figuring on a movie contract in which Clarke is going to pick up Campbell from a descending parachute. For a final thrill Clarke leaves / Here they are—Clarke, the stunt pilot, on the left; and Campbell, the aerobat, on the right the ground in a sharp zoom, climbs one thousand feet in a half circle of the field, then descends in a sharp slant to his point of take-off with his engine full on. Twenty feet from the ground he pulls back the ele- vators and shoots straight up- ward in a_two-hundred-foot climb. At the peak of this climb his airplane is virtually motionless. Suddenly it be- gins to slide back upon its tail; but the weight of the engine pulls the nose downward, and within a nose dive it straightens out three feet above the ground, the tail swinging back and forth. Kicking the rudder straight, Clarke drops her to earth in a perfect landing. The Tractor in the Factory RACTORS have found another place to work. They are not only useful on the farm, but in the factory as he became conscious enough to pull the cord of his ‘“‘chute.’’ well. Building contractors have also been quick to apply The parachute didn’t open until he had dropped six hundred feet farther. The remaining four hundred feet to earth was made in without losing consciousness. Campbell weighs one hundred and sev- enty-five pounds, and when he gets out on the edge of the lower wing it takes unusually fine manipulations of the con- trols to keep the airplane bal- anced. The slightest miscaleu- lation by Clarke would hurl the machine into a tail-spin, mean- ing almost certain death at the low altitudes in which these daredevils work. Frank Clarke, the stunt pilot, is twenty years old, and is one of the few men who have actu- ally taught themselves to fly. In the past three years he has lost only six weeks of flying. safety, and Campbell grinned as he told about it. His opinion is that any one can fall to earth the little tractors in hauling work about a large job. In fact, the small gasoline tractor is always on the job where there is any hard work to be done. It pulls and tugs loads that would require several men to move them. The tractor illustrated is the common farm type with the engine controls placed in the handle. The handle of the fac- tory cart is fastened to the back of the tractor and the ‘‘chauf- feur” sits on the front of the cart holding the tractor handles. In this way he guides the little train in and out the isles of the shop. The gasoline tractor is offer- ing real competition to the electrically driven type that has The farm tractor is coming into use in the factories. come into use during the past Here is one pulling a truck in a big shop 22 few years.

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May, 1921 ‘ Bulkhesd ¥: S yueer Boiler an tas Rooms © Modern Publishing Co. Drawing by S. W. Clatworthy Pulverizing Coal on Board the Ship It Feeds A BRITISH tramp steamer has recently been equipped with an apparatus that handles the coal from bunker to furnace, pulverizing the fuel on the way. It has been found inadvisable to grind up the coal on shore, owing to the tendency of pulverized coal to absorb moisture rapidly, cake badly, and become highly explosive. The great advantage in the use of. powdered coal lies in the fact that. an inferior quality of coal may be used in pulverizing. Even ‘‘sweepings’’ may be used when thus reduced. It is claimed that 40 per cent of waste may be used without lowering the effectiveness of the coal. The reduction in the boiler-room staff, with the corre- sponding saving in wages, is the same as that on board oil-fired ships. In view of the present shortage of oil, many shipping men are welcoming this new method of fueling ocean-going ships

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Popular Science Monthly Ear Books for the Blind A great invention that makes it possible to produce an entire book on a single phonographic record GREAT hu- A manitarian work has been achieved by Dr. Max Herz, of the University of Vienna. Dr. Herz, who is almost blind; has devel- oped a device that means much to every sightless person. A complete pho- nographic edition of Shakespeare may soon be avail- able for sightless people at a cost of fifty cents. The records necessary for this reproduction could easily be placed in the pocket, and the machine for their reproduc- tion, which is a miniature phonograph, could almost be placed in a biscuit-box. Imagine the contents of a novel placed on a small phonograph record measuring about eight inches in diam- eter! Such a record could be manu- factured for two or three cents. A single record would offer hours of amusement for a blind person. The application of a novel principle has made Dr. Herz’s ‘“‘typophonia”’ possible. Vocal sounds are not re- corded, because the recording of such sound requires too much space. The twelve-inch phonograph record in use to-day contains space for the registra- tion of comparatively few spoken words. Dr. Herz has not resorted to the spoken word. In its place, he has brought into use a new telegraphic alphabet made up entirely of various combinations of dots. The Morse telegraph code is made up of dots and dashes, the dash being a prolonged This operator is preparing the perforated tape that is used to control the electric mechanism that records the characters upon the wax disk of the master record By Raymond Francis Yates The electrical apparatus that transfers the characters from a perforated tape to a wax record that is later used as a duplicating master record. Dr. Herz is shown at the left sound, while the dot is a much shorter interval. In the typophonia alphabet no use is made of the dash. Dr. Herz uses two or more dots instead. These are grouped closely so as to follo:v one another in rapid succession. The result is like a number of dotsslurred. This device greatly simplifies the alphabet and makes it possible to record more words. The typophonia record is prepared in a very interesting manner. It was in the system of recording that Dr. Herz was confronted with a problem that taxed hisingenuity. Fortunately, he had 2 faithful assistant who helped him to carry out the details. To translate a book into the typo- phonia code, a paper tape is first pre- pared. The preparation of this tape is strictly mechanical. It passes through a perforating machine that is operated by a trained typophonist. The oper- ator strikes off the typophonia charac- ters with a mechanical telegraph-key. A cutting device responds to the manip- ulation of the key, and produces corre- sponding perforations in the tape. An ingenious apparatus has been developed to transferthesubject matter from the paper tape to an impression- able wax record. The perforated tape moves between two electrical contacts, which meet when a hole in the tape is reached. The meeting of the contacts closes an electric circuit, and this causes a properly regulated current to surge through an electromagnet mounted over the slowly revolving wax record. The current passing through the electromagnet moves a recording needle that is in contact with the revolving record. The move- ment of the needle is recorded as a dot, or a series of dots, upon the record. The tape rushes along at a compara- 24 tively high speed, while the record revolves slowly. Many hundreds of yards of tape are required to fill even a small rec- ord. When the re- cording process has been com- pleted, the record is powdered with graphite to render its surface con- ducting. It is then hung in an electrolytic bath, and metal is de- posited on its sur- face. In this way an exact reproduc- tion of the wax record is made in metal. The metal record is the master record, and, by the use of a hydraulic press and hot wax, as many duplicate records as are desired may be made. The reproducing machine that ren- ders the subject matter on the records audible is a phonograph of special de- sign. No spring or electric motor is used to turn the record. This is done by hand at a slow rate. The needle moves over the record at a speed of only a fraction of an inch a second. The speed can be regulated to suit the reading capacity of the user. The hands of the user turn a wheel mounted horizontally underneath the turntable carrying the record. This wheel is geared to the turntable through a train of gears with the proper ratio. Unfortunately, the typophonia is not yet available for general distri- bution. It is Dr. Herz’s aim to in- terest a philanthropist who will finance the manufacture of the device and sell it at cost. Reading ear books with the typophonia. The records are turned slowly with the hand at a speed that meets the hearing capacity of the person using it ee yee May, i We TN re i bee sten alves ade Vhen lows but vé Rac prevel New | ingeni small arrans warni functi recelv would Wh specié turn | ratus. trols the s nals * os

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May, 1921 Water Starts Radio Alarm }N recent years the fire hazard in factories has ® stems. lows the water to flow. preventing such damage. function during the night. ratus. This automatic sender con- trols a small radio outfit, and when the system is disturbed, radio sig- nals are immediately sent out. VALVE - OPERATED SWITCH Se ial i been greatly reduced by the use of sprinkling The water is started by automatic alves that are normally kept closed by a plug ade with an alloy having a low melting-point. Vhen this is heated slightly, the alloy melts and Fire is thus quenched, but valuable goods may be damaged by the water. Radiotelegraphy is going to find another use in William Dubilier, of New York city, has solved the problem by an ingenious application of radio. He would installa small radio-sending outfit in each factory, so arranged that it would automatically send a warning signal when the sprinkler started to The signal would be received by a central station, and a messenger would be despatched to turn off the water. When the water starts to flow in the pipe, a special device closes an electrical circuit, which:in turn sets in motion an automatic sending appa- AUTOMATIC SENDING APPARATUS Since hiccoughs are caused by the spasmodic contraction of the diaphragm, pressure on the dia- phragm may cure them TO VALVE -OPERATED| | | |¥0 LOOP INDUCTION | [ANTENNA — COIL * ih ay | sparn cap [aie fESeae? a 5 - =§ ¥ i =~ ; ond 7 Spans IS AUIOMATIC TRANSMITTER CONDENSER 7 TUNING) INDUCTOR The radio equip- ment used to call assistance. Water passing through a valve operates the radio outfit > LOOP ANTENNA a“ AUTOMATIC SPRINKLERS a glottis. As the air way you reach the Water flowing 1n the sprinkler system causes a radio outfit to call help from a central station interest in its cure. to contract? this nerve becomes the resulting noise is the hiccough. Health Commissioner of New York city, suggests that if you prevent the contraction of the diaphragm you will usually prevent the hiccoughs. fingers under the v shown by Dr. Copeland in the picture above. Now comes the question The disorderly nerve that causes the diaphragm to contract may be quieted by pressure on the fifth cervicular nerve Hiccoughs—the Cause and Cure ITHOUT warning you are attacked by hiccoughs. Per- haps you try holding your breath or looking at the ceiling while you swallow desperately. There are many other hiccough ‘“‘cures,”’ but few of them get at the heart of the trouble. A hiccough is caused by the spas- modic contraction of the diaphragm, accompanied by the closing of the rushes up, the epiglottis drops; and Dr. Copeland, You press your ictim’s floating ribs, in the manner In that diaphragm. Some months ago New York city experienced a mild epidemic of hiccoughs, which explains Dr. Copeland’s what causes the diaphragm The agitation of a nerve connected with it. When a man has drunk too much alcohol, for instance, poisoned, and hiccoughs result. Reviving Dead Tennis-Balls with a Pump HERE is one thing that will bring a dead tennis-ball back to life—air. But how can air be in- jected into a tennis-ball so that it will stay there? By means of an instru- ment that looks and acts like a hypo- dermie syringe. The tennis-ball itself must be specially made. Before the felt cover is placed around the inside rubber ball, a small lump of soft rubber is attached to the inner surface of the ball. The needle of the syringe is in- serted at this spot, and the handle is The arrow points to where the pump needle is inserted. A knob of rubber beneath prevents air from escaping 25 pushed down. In this manner the rubber ball is given the proper degree of inflation. When the needle is withdrawn, the air pressure within causes the soft rubber to close over the hole. Next the felt cover is ad- justed and a dot or small cross on the cover marks the spot where the needle was injected. After the ball has been in use awhile it loses some of its resiliency and needs an additional charge of air. What then? You insert the needle at the marked spot and push the handle

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Popular Science Monthly —~ 15000 FT 10000 Fl. _—______—_—- > 6 NEW MEXICOS One Cloud’s Energy Equal If the energy that is stored in clouds could by any means be converted into usable form, the world would have at its service one more source of power. A cloud is a mass of material so light that it floats in the atmos- phere; yet its particles were put there by the expendi- ture of energy, and this means just that much power to be put to use if it could be harnessed. It has been estimated that the total weight of a cloud 5000 feet above the ground, and measuring to that of Six Battleships 10,000 feet in diameter, would be equal to some 200,000 tons when condensed In tropical countries, where gigantic cumulus clouds reach into lofty mountainous heights, the actual weight of such a cloud might balance that of six battleships like the New Mexico. In the past year or two much research work has been done in an attempt to wrench from nature new sources of power 26 May, 1 Ta: dr by fre ‘ies WI f ene that e! isable service Hov power can re cloud light t ocean, suspel Never! there and t weigh put i much V Col sand fiftee! measi eter. cylin dome the te Fo sider havir The 7 be t' This thun and that exarr TI evap surrc¢ carr leav grad oute 7 biun the ' of | divi and B woo to t Popular Science Monthl; M

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May, 1921 Every Cloud Is a Power HE mass of a great thunderhead drifting across the sky, illuminated by frequent flashes of lightning, car- -ies within itself an immense amount £ energy, or power to do work. [If all that energy could be converted into a isable form, we should have at our service a new source of power. How can there be great weight and »ower where material is so light that it can remain suspended in the air? A cloud is indeed a mass of material so light that it floats in the atmospheric ocean, an “iceberg’’ of vapor wholly suspended and submerged in the air. Nevertheless, its particles were put there by the expenditure of energy, and the force capable of lifting the weight of the material of the cloud has put into the mass just exactly that much power to do work. What a Thunderhead Weighs Consider a mass of vapor five thou- sand feet above the ground reaching fifteen thousand feet skyward and measuring ten thousand feet in diam- eter. It is not a mass of exactly cylindrical form, but irregular, and dome-shaped or ‘‘mushroomed’’ on the top. For convenience we may _ con- sider the cloud as a gigantic block having a square base and oblong sides. The volume of such a mass would then be two thousand billion cubic feet. This is not a mass too great for a thunderhead. Some clouds are larger, and others scattered smaller masses that on the whole, would surpass our example in size. The warm air drank in the moisture evaporated from land and sea. The surrounding pressure of cooler air How ORKING from the outside in, when studying a tree’s growth, the bark is the first consideration. It is of a corky nature and is composed of dry dead leaves. The bark protects the tree against evaporation and out- side injury. Beneath the outer bark is the inner bark, which is soft and moist. It carries the food that is prepared by the leaves to all parts of the tree. Very gradually, this inner bark becomes the outer bark. The next layer, known as the cam- bium, is where the actual growth of the tree takes place. It is a thin layer of living cells that divide and sub- divide, forming on the inside wood and on the outside bark. Below the cambium we find sap- wood, which carries sap from the roots to the leaves. Heartwood composes Ifnes 1007 By Latimer J. Wilson caused the warm mass to ascend like a hot-air balloon. You can see these thunderheads mounting skyward on a warm summer day. The rising speed averages more than one hundred feet a minute, and is gradually reduced as the top of the cloud reaches the point where it is cooled to the degree of the surrounding air. The process of cool- ing under pressure ‘squeezes’ the moisture out of the heated air, and, in the form of minute globules formed on dust nuclei, it drifts in the currents. The cloud assumes various shapes as the transition takes place.. Often the top of the thunderhead bursts out in surprisingly beautiful mushroom forms and stands in the sky like a vaporous toadstool reared in an interval of a few minutes as if by magic. The rising atmosphere really cools by the work of expansion, and this occurs as the pressure decreases. But within the cloud violent forces are at work. The pressure of -sur- rounding cooler bodies of air rush into the forming mass with the strength of ahurricane. The globules of water are massed together into drops of rain, and these are hurled upward with the cur- rents. Sometimes they are carried high into the region of freezing tem- perature and are congealed into ice. The lumps of ice fall, and then a severe hailstorm descends beneath the thun- derhead. The friction resulting between the violent elements of disturbance pro- duces fields of static electricity and lightning flashes from point to point in the cloud. Hence the name ‘‘thunder- head.”’ It is thought that the elec- to Tell the Age of a SAPWOOD OUTER AND INNER BARK >’ , ae yy Ty yn} : ae x Yy Vp

How a tree tells its history; the “cambium”’ shows the years it has to its credit House trical energy is due to the separation or rupture of the raindrops them- selves. Assuming the cloud to be composed of water vapor to the point of satura- tion at freezing, the total weight of the condensed cloud would be about 200,491 tons. <A battleship the size of the Iowa displaces 43,000 tons of water. The cloud then would have the displacement of four ships the size of the Jowa. If all of the water in such a cloud were suddenly precipitated upon the ground, imagine the fury of the cloudburst. Tons of Moisture Lifted This vast amount of water would normally be spread over an area nearly two miles square. But imagine the deluge if all of the water in the cloud could be converted into a single channel and poured as through a funnel on one small spot upon the landscape! It is interesting to conceive of the subtle force of nature that can lift this huge load of material to the height of the cloud. Working against gravity, the sun through its warmth evaporates the moisture from land and sea, and without the aid of man is able to lifi tons of invisible moisture high above every square mile of the earth's surface. Here, then, is an _ inexhaustible source of energy, if we could but har- ness it. Only that part of the water that collects upon high places, moun- tain basins and plateaus, are we able to use. The waterfalls from the clouds offer unheard-of opportunities which are yet far beyond the reach of men. Tree the next layer in most trees, not every tree has heartwood. In the very heart of the tree is the pith, around which the first woody growth is formed. From this heart of pith extend rays, connecting the pith with the various layers of wood and the bark, and also storing up food. Each season’s growth is known as an annual ring. Count these rings and you have the age of the tree. It is important, particularly in the United States, that the owners of land containing an appreciable number of trees should become familiar with the various species—their value as lumber or for shade, also the age at which it is best to chop them down. And it is well to remember that for every tree that is chopped down another one, or even more than one, should be planted for the use of those who come after. though

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i WA i ™ Every beaver dam, it has been estimated, costs the state ninety dollars, the beavers destroying valuable trees to carry on their work Why Beavers Must Go IX years ago there was no sign of beavers in the Adirondacks. Today the forest is full of them and their work is everywhere. This comes as a result of restocking the Adirondacks with thirty-four beavers in 1906 and 1907. There are from ten to twenty thousand dam-builders in almost every watercourse and lake. Rangers of the Conservation Commission of New York state have inspected 587 dams, which flood 8681 acres of forest land, covering with water $51,425 worth of valuable timber. It is estimated that every beaver dam costs the state ninety dollars. The destruction will increase rapidly. cherry, and other trees, many of which are a foot or more in diameter. They girdle and kill many larger ones and flood many acres, thus drowning the roots of priceless timber, es- pecially pine, spruce, and bal- sam. Something must be done to curb the destruction. This will probably be accomplished by means of an open trapping season next year. It is inter- esting to remember that when the white man came there must have been more than a million beavers, for the simple mind of the redskin associated the beaver with the creation of the world and revered the creature too much to kill it. The invention of the steel trap about 1794, and the use of castoreum as a bait, together with the great demand for beaver hats in that period, took a terrible toll of animals. By 1895 there were probably not more than five beavers in all New York state. Then in 1895 the legislature of the state protected beavers The beavers cut birch, poplar, Popular Science Monthly Removing Ashes with Steam STREAM of steam, moving with sufficient velocity will carry considerable solid matter along with it In this respect it acts exactly like air. An ash-conveyo that is nothing more nor less than a heavy pipe wit! steam flowing through it, is now in use. This pipe run under the ash-pits, and the ashes are dumped directly int this. The steam, traveling at high velocity, whisks th ashes away, carrying them to a hopper outside. Th, ashes are emptied from the hopper directly into th trucks that carry them away. This is a quick, dustless, inexpensive operation. Ashe are very abrasive, and machinery used to handle the: does not last long. Let } ASH RECEIVER By the wheelbarrow methox a man may load and whe: approximately 200 pounds o ashes a distance of 100 feet ir, five minutes; 2400 pounds a hour; 934 tons in an eight hour day. With the steam jet conveyor the same un skilled laborer will move th same tonnage of ash in one an: one half hours. A steam pipe passes under the ash-pits and the steam carries away the ashes, depositing them in a hopper outside the boiler-room As Substantial as the Pyramids OTHING is more unsightly than a huge struc- ture of corrugated iron. At Ishpeming, Michigan, there were two such monstrosities in the shape of shaft-houses belonging ) to an iron company, and their | appearance became worse and worse, until it was very plain that something must be done about it. Work had to be continued while reconstruction was going on It was decided that the best way to accomplish the re- form was by concreting the shafts. The concreting started in the summer, but cold weather set in before it was completed, | and the sand and cement had to | be heated before it was poured. Then the fornis were allowed to E stand until spring. The result was entirely satis- factory. Thetwo shafts, which are located conspicuously on a hill, at a distance strangely resemble the Pyramids. Head- frames of this character are more cheaply constructed than are steel frames, and the up- keep is comparatively low. There are no bolts to be kept by law, and a few years later their homes and dams as well. After concreting a corrugated-iron shaft-house of an iron-mine of the hematite class 28 tight and of course no painting is necessary. Ma J ( not ror ne T Joh a st mal leng abo Joh firm plac han nec left opp C stro wis! ing leas hig] I psy scie wat ane cor doe still Cou he mal lear pro! A con mys cent - G Anc tha righ It? CoV us j \ dow han Wit out to | saw han The a to fork ing tone the the to |

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RM ja tid .d- ire an ip- Ww. ‘pt ng ——— Be aso 3 May, 1921 What Is Johnny Coulon’s Secret? All the strong men of France have tried -OHNNY COULON is still an un- J solved mystery. When he wills it, not ‘fall the king’s men”’ can lift him from the ground—and he weighs only ye hundred and eight pounds. These are the regulations that Johnny demands before he will allow a strong man to tackle him: the strong man must face him, stand at arm’s length, and then take hold of him above the hips and yet below the ribs. Johnny, in the meantime, stands firmly and erect on the floor, and places one or two fingers of his right hand on the left side of his opponent’s neck over the carotid artery; with his left hand he touches the pulse of his opponent’s right hand. Can he be lifted? Not by the very strongest man in France—unless he wishes it. Then, without visibly mov- ing or changing his position in the least, he allows himself to be lifted high in the air. Is the cause of this strange power psychical or physical? Physicians, scientists, and psychoanalysts have watched Johnny repeat this perform- ance in Paris until his sides have be- come painfully bruised and grazed; his doctor has ordered him to stop. And still they do not understand him. Coulon himself says that by his contact he stirs a certain nerve fluid that makes his opponent powerless. The learned men who are studying the problem do not believe this. All kinds of experiments have been conducted in an effort to solve the mystery. Thinking that perhaps the center of gravity of either Coulon or Blow Music Is Produced from ‘O to the tool-box and get your J saw. Perhaps it is a musical one! And there is no sound sweeter than that which can be drawn from the right kind of saw. How do you play it? Ford Hanford, the man who dis- covered the saw’s musical powers, tells us its secrets. When he wishes to play, he sits down, crosses his legs, and places the handle end of the saw between them. With his left hand he firmly grasps the outer end of the saw, so that he is able to bend it at will. Next he gives the saw a sharp blow with a felt-covered hammer-——and then the music starts. The blow makes the saw vibrate with a tone that suggests that of a tuning- fork. By bending the saw and chang- ing the curvature, he produces other tones after a blow has been struck and the saw is still vibrating. As long as the original vibration lasts he is able to play a phrase by bending the saw Johnny Coulon puts the fingers of his right hand on his opponent’s neck near the carotid artery and touches with his left hand the man’s right wrist pulse, and remains immovable his opponent was displaced, Professor Charles Nordmann asked Coulon to remove his fingers from his opponent’s neck and to lean first backward and then forward. In both cases he was easily lifted. Next a chain of three men tackled him. Coulon touched the first and third on the neck and pulse, while the middle man tried to lift him. Both By holding the ends of the saw firmly and hitting it a sharp blow with a felt hammer, vibrations result that cause the saw to pour forth music 29 in vain to lift him end men touched the middle man on the wrist—but Johnny could not be moved. Yet, when Coulon placed his fingers on the neck and pulse of a strong man who attempted to lift a man other than Coulon, he had no power over the strong man. There were found to be several con- ditions under ~vhich Coulon’s power diminished— it his fingers were wet, if his feet were not flat on the floor, or if a piece of paper were placed between Coulon’s fingers and his opponent’s neck and wrist. Professor Nordmann finally came to the conclusion that Coulon exerts some physiological and psychological force. It is not like an electric current or like any other force known to physiologists. When Houdini, the great American strong man, was asked what he thought of the Coulon stunt, he said fervently: “It’s hokum!” He claims that Coulon is playing tricks on the French scientists. ‘It’s the principle of the fulerum,”’ said he; ‘‘a matter of leverage.”’ Coulon is in stable equi- librium and his subject isn’t. Coulon keeps his subject at arm’s length to get the best advantage of the leverage. “Furthermore,” says Houdini heat- edly, “the trick has been played be- fore.”’ This is true. There was Lulu Hurst, and then Annie Abbot. Both of them were vaudeville performers who did the same thing. Miss Abbot, we find, weighed ninety-three pounds, yet she challenged the men in her audiences to lift her. a Saw into different positions. It took hours of practice to obtain satisfactory tones. He sits on the stage of a New York theater and, with his partner, Mr. Myers, thrills the audience that listen to the “Greenwich Village Follies.’’ The saw he uses was not specially made; he selected it in a hardware store after trying out several of them. The music it gives is loud enough to reach every corner of the theater. A bass viol bow well resined, Mr. Hanford finds, will produce even better music than the hammer. He draws it swiftly across the smooth edge of the saw, repeating the process whenever the vibrations die down. The incredulous think that Mr. Han- ford produces the music by means of an instrument placed in his mouth. He has perfect control over the saw, but says that his left hand soon be- comes tired because of the strain to which it is subjected.

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Popular Science Monthly Revolutionizing the Glass-Blowing Industry The change from lung power to machine in the ancient art of glass-making reads like a romance N 1894 a man stood on a chair with | a glass-blower’s pipe in his hands, the lower end of which rested ina bowl of molten glass. He was trying to prove to a second man that glass- blowing by machine was possible. As he blew into the cold end of the pipe, he lifted it, causing a cylindrically shaped bubble to form at the opposite end. The other man promised to supply the money necessary to de- velop the machine. An_ industrial romance had its birth. John Lubbers was the man on the chair. He showed the world how to make window-glass by machine. He created a new art from the hopeless debris of an old one—that of producing glass by hand and lung. James A. Chambers, president of a glass com- pany, was the man who had faith in Lubbers’ ideas. Before Chambers met Lubbers he had made a comfortable fortune in the glass business. He was the first man to introduce the Belgian tank: glass furnace into the United States. Lubbers was a glass-flattener by trade and an experimenter of the most persevering type. Some people would call him a genius. The simple truth is that he worked, worked, worked. He was so obsessed with his idea—that of manufacturing window-glass by ma- chine—-that he did not have time to think about failure. Making Window-Glass the Old Way The history of making window-glass has no authentic beginning. The vellow pages of a book published in 1639 tell how the art was practised before that date. There were few changes made during the passing cen- turies. It remained for John Lubbers to blaze the new trail. In the old process of blowing win- dow-glass cylinders by hand, the work- er takes a long wrought-iron pipe with a bell-shaped opening at one end and a plastic mass of hot glass attached to it. He blows with his mouth into the opposite end of the pipe, and by careful manipulation causes a glass cylinder to form. By reheating this glass bubble and continuing the blow- ing, a cylinder is finally produced that may be as long as seventy inches with a diameter of twenty inches. When the cylinder has cooled, it is broken away from the pipe, and a crack is produced along its entire length, so that it will flatten out when it is placed in a suitably heated furnace. Cooling, polishing, and a few other minor operations bring the flattened By Raymond Francis Yates glass to a marketable condition. This is the old process. By this time, probably, you have figured out a method of blowing glass cylinders by machine. Just attach an air-pump to the end of the pipe and blow the glass bubble by compressed air. Why didn’t somebody think of this before? The fact is, many people had thought of it before, but they did not realize the obstacles that stood in the way. When Lubbers stood on the chair showing James Chambers how glass cylinders could be blown by machine, he promised to be doing it in this way within three months’ time. Ten years later he had assembled a machine that gave some promise of success. By that time nearly three million dollars had been spent in experimenting. A powerful union of glass-blowers at one time controlled glass manu- facture in this country. They dictated their hours, wages, and output. Their organization was so strong that no one could learn the trade unless he had a relative who was in the work. The glass-blowers’ union heard of Lubbers’ work. His life was in con- stant danger. But Lubbers was not a coward, and he vowed that the union should not stand in the path of progress. James Chambers formed a company to carry on the experimental work. John Lubbers, the uneducated glass- flattener, rolled up his sleeves and went to work on one of the most per- plexing problems that has ever en- gaged an inventor. He little realized what faced him; nor did Chambers know that it was going to lead him to financial ruin. Their greatest asset was faith. An experimental plant was built at Allegheny, Pennsylvania. Lubbers was in his glory—he was striking into the unknown with nothing to guide him. Three months slipped by. Then six months. His promise of success with- in three months came to nothing. The first machine was crude. The ordinary glass-blowing pipe was em- ployed. This was hung vertically over a pot containing the molten glass, and at the upper end of the pipe a hose was attached through which a stream of low-pressure air was forced. The pipe traveled slowly upward as the glass cylinder became larger. Commercially, this machine was ab- solutely impossible. It was found that cylinders could not be blown any larger by this method than by hand 30 and mouth, and those that were blown were worthless. They were thick on one side and thin on the other. Cooling strains also developed in the glass as it passed from the liquid to the soiid state, so that ‘t was abnormally brittle. The outer surface of the glass, which was in contact with the air, would cool by radiation before the inside had set. This hard crust of glass on the outside prevented the natural process of expansion when the inside cooled, causing molecular strain that made the glass very sensitive. The cylinders were not only blown “thick and thin,” but they were also blown in a corrugated fashion. There was a breathing effect within the cylinder that caused this; but at the time that was not known. Poor Lubbers was beset with many other discouraging difficulties. Taking care of the glass that remained in the pot after drawing a cylinder was a baffling problem. The bath of glass had to be melted to a perfectly uni- form temperature before it could be drawn successfully. To remelt the glass in the pot took time. The Patience of Job Lubbers was a patient man. One by one, he overcame the obstacles. Little by little, his experiments pointed out the right path. It was found that the air forced into the cylinder had to be kept at a uniform pressure. A small hand-valve was fitted to the apparatus, and the air supply was graduaily regu- lated as the cylinder was drawn. The results of this makeshift were lament- ably bad. Val)ves of every type were used, but the regulation was entirely too coarse. Finally an automatic valve was developed that effectively increased the pressure of the air as the cylinder became larger. The corrugations remained in the cylinders despite the perfect regula- tion of the air. Lubbers, who was not a scientific man, could not determine the cause. After six years of experi- ment, the mystery remained un- solved. Lubbers placed a vent-hole in the closed-air system, so that the excess air could escape. This was a master stroke: it worked like a charm. The corrugations were entirely elimi- nated. The art of blowing window- glass by machine was brought from a bare possibility to a fairly practical stage. By the use of a suitable shield, which protected the glass bath, and a small refractory ring that floated on the surface and through which the glass

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May, 1921 cg PERATORS " = a ai F K | VARIABLE Ps AIR VENT i i * BRyiaae = et SUPPORTING hi FRAMES GAS-BURNERS2@& aa * oe After Centuries Glass Is Now Blown by Machine This is the interior of a modern window-glass factory. Here great glass cylinders are blown by compressed air. The molten glass is held in a reversible refractory pot that is heated by a gas flame. This pot is filled with glass from a “tank furnace.’’? The blow-pipe is lowered into the molten glass contained in the pot and a carefully regulated supply of compressed air is then admitted to the pipe while it is slowly raised. As the pipe travels upward, a glass cylinder is gradually formed. A variable air vent maintains the proper ratio between the volume of compressed air admitted and the growth of the cylinder. This regulation is absolutely necessary to produce a cylinder of uniform thickness and diameter. As the glass cylinder moves upward, it is exposed to the outside atmosphere and it “‘sets.” After the cylinder is completely drawn, it is broken from the blow-pipe and hauled down. It is then cut into short lengths with an electrically heated wire and the lengths are placed in the flattening furnace after they are split from end to end. In the flattening furnace, the glass cylinders flatten out into a big sheet of window-glass, which is later cut up into the standard sizes

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Popular Science Monthly In the older process of window-glass manufacture, glass-blowers place a ‘‘bait”’ blowing with the mouth they produce a cylinder about four feet long. must be reheated several times before it reaches maximum size was drawn, the process was brought another step toward success. Chambers exhausted himself finan- cially. He had spent two hundred and fifty thousand dollars, and at this time called in some business associates. The work went on until 1901. At the end of this period a million dollars had been invested. Were the experi- menters discouraged? Not at all. They decided to discontinue the ex- periments at Allegheny, and lease a larger plant at Alexandria, Indiana, where the work would be carried on approximately a commercial scale. Success Slowly Approaches It was at this time that Lubbers found it necessary to give three dif- ferent speeds to the upward travel of the crosshead that carried the blow- pipe. In blowing larger cylinders, the glass at the bottom started to cool ap- preciably at the end of the draw. To compensate for this, three different speeds were used, so that a cylinder of uniform longitudinal thickness would be produced. The speed was finally brought un- der control by the employment of a magnetic clutch on the hoist that lifted the crosshead. But the struggle was not yet over. Thick and thin cylinders were still being drawn, and no one knew why. The time required between the drawing of cylinders was too great, and the process could not be brought to a commercial basis until this difficulty was eliminated. One of Lubbers’ helpers, a man named Thornburg, invented and pat- ented what has become known as a “double reversible pot.’’ This was really two pots arranged back to back, just as if we put two dishpans together, bottom to bottom. Molten glass was ladled into the upper pot, and the cylinder drawn; then the pot was turned over and fresh glass ladled into the upper one, while the one pre- viously used was exposed to the heat of the furnace underneath. In this way the glass left in the pot after a draw was completely melted out and the operation made continuous. In 1903 it was decided to abandon the plant at Alexandria and _ start anew at Gas City, Pennsylvania. After Chambers had spent his last dollar in the work, a powerful com- bination of glass manufacturers took control. The experiments were carried on as secretly as possible, but mem- bers of the glass union heard of them. Realizing that their control of the industry was jeopardized, they left their jobs and went into the employ of companies that were not financing the new process. The glass combination did not close down its new plant. They went ahead and installed machines that were pro- ducing 80 per cent waste! Sheer in- dustrial bullheadedness. A number of plants were equipped with 20 per cent efficient machines, and the work went $2 on the end of a blow-pipe, and by This work is so slow that the cylinder on. Lubbers ate, slept, and thought in the glass plant. Like Pouring Money Down a Hole Two or three thousand dollars were lost every day. One veteran glass manufacturer, whose _ invest- ments ran into the hundreds of thou- sands, declared he would sell his in- terest for a square meal. Lubbers was almost at his wits’ end. Perfect cylinders were drawn merely by chance. The real trouble was a difference in surface tension brought about by slightly different temperatures in va- rious parts of the bath. Lubbers knew nothing about surface tension. H¢ had. a watchful eye, however, and noticed that the cylinder usually traveled over the surface of the bath as it was being drawn. He finally hit upon the simple idea of initially ad justing the bait to, the one side of th bath in the opposite direction to that in which the cylinder was traveling. The impossible happened. A succes- sion of perfect cylinders was drawn. Lubbers had conquered. Develop- ment work went on rapidly. In 190’ the glass combination actually began to make money. Its books showed a net profit of forty thousand dollars. Today two thirds of the glass manu- factured is made by machine. Cylinders blown by hand reach seventy inches; blown by machine they reach forty feet!

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it by Va- ew He nd lly ath hit ad th: hat ng. »eS- a lOp- 90! gan od a ars. nu- ach anne May, 1921 TERETE “Hello, Central! Give Me the Mauretania” Soon we shall be able to take the telephone rcceiver off its hook and ask the operator to connect us with a ship halfway across the ocean. When this is possible, the operator will connect your telephone with a_ powerful radiotelephone station. At the telephone wire will be connected with the radio phone apparatus, and the voice will be wafted over the seven seas. On board the ship, another radiophone station picks up the message, and routes it through to the friend with y WOE | exchange to the radiophone station, this point the voice is hurled into space. The home or office telephone be heard at the opposite end, whether he be in Hongkong or Berlin the radiotelephone station whom you wish to speak | ELECTRIC-VALVE VOICE- ALEXANDERSON HIGH 7 | [ CURRENT AMPLIFIERS FREQUENCY ALTERNATOR TUNING Hif A HELLO! | | TO CHARGE AY ~ a) / ANTENNAE. ¥ | -~ % ~~ | | as | 4a \ | SWITCHBOARD IN - I TELEPHONE EXCHANGE I This diagram shows how it ‘‘works.” || We speak into the receiver, and the’ is simply connected to a powerful ' voice passes through the telephone radiophone equipment. The person at the other end of the ‘line’ can which may be miles away. From _ also speak into the transmitter and Z

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WING eco REFLECTIONS i 74) cal ~— 6, secre oe ee tp meer ec sees te ae ee ————————— Catching the Eye to Advertise Hair-Cuts | ERE is a new adaptation of the barbers’ ancient sign. A _ re- volving pole of red-and-white-striped glass containing electric lights is re- flected in a number of oblong vertical mirrors arranged in a concave curve behind the pole. The invention is that of Peter Zarella, of Boston, Massa- chusetts, and the optical illusion produced is that of a series of ascending spirals. Both the top and bottom of the pole and the reflections are cut from view by strips of ground glass. Placed in a window or in a street show-case, such a sign is sure to attract attention. A fiftieth-horsepower motor supplies the power. House Delivered by Motor-Truck “CEND me one of your four-room houses, C.0O.D.”’ A strange order, but it is possible that before long you may be giving that very order yourself. A French engineer is now building complete houses, which are placed on wheels and delivered to your lot by motor-truck. An average price for a house is $835. There are two floors, connected by a staircase. The four rooms include a kitchen and heating plant. The house is eight feet wide and fifteen feet high. The upper floor can be lowered for traveling, and the house becomes nine and a half feet high. This is achieved by sliding walls. Built on Stilts, It Cast an Unlucky Shadow T Soochow, China, an American oil company had all the ground for its building, except for one small square. The owner refused to sell because the building to be erected would cast an “unlucky” shadow on the next lot, which he also owned. The Yankee manager almost despaired, when a Chinese assistant heard of the difficulty. He visited a geomancer—a sort of soothsayer, supposed to interpret the wishes of the natives—and returned with a drawing of a cheap bamboo tower which was put on a spot selected after an entire day spent in pacing and measuring. No sooner was the structure completed than the owner of the coveted property called on the manager of the oil company and offered to sell. The reason for the Chinaman’s speedy change of mind was that the bamboo tower was so placed as to cast an “un- lucky”’ shadow on the house that occupied the desired lot. Popular Science Monthly This Battery Works Only When Needed RY cells have never been very successful when used in con- nection with fiashlamps. Storage cells are impossible. A new cell has been perfected that uses lead and zinc elements. It is really a wet battery of radical de- sign, and it is so arranged that the active chemical comes in contact with the plates only when the light is in use. When the light is tipped upward, the electrolyte drains off the plates and runs into a separate chamber, where it remains until the light is tipped back into position. When the electrolyte reaches the plates of the battery, current is generated, When a Ship Runs on the Rocks NLY battleships are built to withstand the test that the Scarpa, shown below, is called upon to withstand. It is not a deliberate test of stanchness. The Scarpa ran on the rocks off the coast of Ireland. Like most merchant steamers, only about half an inch of steel plating constitutes the Scarpa’s hull. It is easy for the waves to pound her against the rocks and to puncture her plating. A battleship is built with more than one hull, one inside of the other, not to mention a honeycomb of cells in the bottom. It would not pay to build merchant ships in the same way. A mo ste he cyt po tar the W) wil hir thy Or ac on ter th th dr. st oil

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May, 1921 He Rounds Up Steers on a Motorcycle T the “round-up” in a “bull-dogging contest’”” at Mason City, Iowa, a motorcycle won the honors of the day. The object of the game is to catch the steer by the horns and twist his neck until he falls, then quickly tie him before he has a chance to get up. The tandem motor- cycle far outdistanced the cowboys on ponies in the contest. Daring Jim Lynch, a cowboy riding tandem with S. J. Snyder, who was driving the machine, performed the dangerous feat. When the steer was running neck to neck with the riders, the cowboy sprang upon him and seized his long horns, quickly throwing the animal. Machine-Oil that Sells Itself 1% spite of so-called ‘“‘crime waves,” store- keepers grow more trusting every day. One of them—he sells sewing-machines and accessories—permits his customers to wait on themselves at the ‘“‘machine-oil” coun- ter. They select their bottles of oil and then drop the proper amount of money through a slot; it lands in.a locked drawer. The oil counter is a converted dresser, and it stands conspicuously in front of the store. The bottles of oil are arranged across the top, as shown in the pic- ture, and the coin- box with its slot is located in the center. Here’s the Giant Among All the Pencils OMETHING § different—that’s what many actresses hunt for. One of them decided to own the largest usable pencil that she could have made. Hereitis. It measures twenty-six inches in length and one inch in diameter. There is a real eraser at the end and real lead throughout. The lead is made from a graphite com- pound similar to that used in drawing- pencils. It was hydraulically forced through a special sapphire die and came out in the form of a shoe-string. It was straightened and dried, during which process it was subjected to a heat of two thousand degrees. Graphite, from which pencils are made, is imported from Mexico and Ceylon. A Snake-Charmer’s Secret OW does the snake-charmer charm? That’s one of the questions we’ve always asked ourselves. And now an English doctor tells us one of the secrets. Take the case of the cobra, for instance. It is a very venomous snake, yet the snake- charmer is not harmed when bitten by one. The secret lies in the fact that the charmer “‘milks’’ the cobra before he allows himself to be bitten. He makes the cobra bite into a piece of meat, thereby expelling two thirds of the poison in its poison gland. When the charmer allows the snake to bite him immediately thereafter, there is not enough poison left in the gland to do any harm. What is the next step? The charmer makes the snake bite a fowl while he squeezes the remaining drops of poison out of the snake’s‘gland; the fowl dies, and the charmer wins the confidence of his audience. 35 Protecting a New Road from Sun and Rain at poured concrete must be pro- tected from the sun and rain. The sun causes it to dry out too rapidly, and this is liable to produce cracks. The rain washes the fresh concrete away. To protect a newly built road, the road- builders first lay canvas on the surface. This is to keep the rain off. A covering of straw is then laid on the canvas. This protects it from the hot sun. The straw is wetted slightly to prevent the road from drying too quickly. The road is protected in this way as fast as the concrete is poured, so that there is no danger of having to do the work over again. Taxis Hailed by Slot-Machine AXICABS are always hard to find when it is raining. The man in the picture below is dropping a coin into the slot, and in a few moments a cab will rush up to the curb for him. This is the new way of calling taxicabs in Germany. When the coin is dropped into the slot, an electric circuit is closed and a lamp flashes at the taxi headquarters. This lamp tells just where the waiting per- son is, and a cab is despatched to the location.

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* * ‘ ae 5 tag? He Is Telephoning from the Pole . is now easy for fire departments to telephone from the fire-engine in the midst of fighting a blaze. The fire department at Glassboro, New Jersey, has a lineman on its crew who has rigged up a device that can be used wherever there are overhead telephone-wires. The equipment consists of a double length of covered telephone wire, about fifty feet long, with clasps at one end for hooking to the wires, and a portable tele- phone at the other end. When the fire crew gets out of reach of the regular tele- phones, all they do is climb the nearest pole and hook on the connection. To Hear the Baby Cry gameerapl-ipe vary in regard to the treat- ment of a crying baby. Some let the baby cry; others rush to pick him up. A father belonging to the latter class worried considerably because he could not hear his child cry at night! The child slept a distance from the father’s room. What did the father do? He had three loud-speaking telephone transmitters in- stalled over the baby’s crib and a receiver placed over his own bed! Euphorbia—the Porcupine Plant VERY singular desert plant has re- cently been discovered in British East Africa. It is known to botanists as Ku- phorbia eustacei, and often exhibits a most remarkable habit of growth. Like so many other plants that thrive in dry locations, this euphorbia produces long spines that practically cover it. Hence the plant bears an astonishing resemblance toa porcupine. Indeed, a traveler coming suddenly upon the plant, finds it difficult to believe that he is not looking at one of these animals crouching between the rocks. There are many other instances in which plants and animals resemble each other. The butterfly, for instance, often has the same coloring as the flowers among which it lives. Thus nature protects it from attack. No More Trains Will Pass Over This Bridge HE last train has passed over this bridge. Engineers have warned that it is unsafe. It is a unique bridge, too. There is not another like it in the world. More than 3,800,000 feet of lumber was used in its construction. It stretches across a valley that is thirty-two hundred feet long. The bridge is 118 feet high. It is situated near Camrose, Alberta, Canada. Wooden trestles are out of date and un- safe. The rolling stock of the railroads is becoming too heavy for the old wooden trestles. Steel is now considered the best trestle-building material. Long ago it replaced wood. Popular Science Monthly . © Kadel & ae | Herbert ‘‘Scooting’’ Among the Natives in South Africa HO invented the wheel? Probably some caveman. At least, history does not record the date. The wheel was probably invented all over again, as far as this black boy is con- cerned, when he used his ingenuity to make a scooter for himself. He baked clay in earthen pots, first placing the bamboo ‘‘axles” in the center. The wheels were then attached to two bamboo rods and the first South African scooter had its birth. Above you see its dark little owner on his way down a hill. He deserves a lot of credit, for he is a real inventor. Canned Tennis-Balls EAD tennis-balls are worse than useless. What makes a ball go dead? Atmospheric conditions very often. However, if tennis-balls are canned— hermetically sealed—when manufactured, they will be as good as new when opened. This has been done recently in shipping tennis-balls to China. Heretofore the balls have lost much of their resiliency because of the long ocean voyage. But now, they are not affected by the journey. Whi R* woul was | upon the j train A | engil collis So was rolle thro most and from char N kille i} for s He’ a Sa fron eye) ver clos slop bar bae cye

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May, 1921 What Wrecked This Jungle Train? I ECENTLY, in Indo-China, not far from Saigon, a big-game hunter had wounded a large bull elephant, which he was unable to follow up. The beast came upon the railway where it passed through the jungle, and, scenting the approach of a train, charged down the track to meet it. A bend hid the elephant from the engineer until it was too late to avoid a collision. So great was the shock that the engine was thrown completely off the track. It rolled over on its side. The tender was thrown across the line, and the two fore- most cars were also derailed. The engineer and fireman escaped injury by jumping from the cab just before the elephant charged. Nobody was hurt. killed outright. The elephant was Comfort and a Motorcycle HE American user of motor ‘‘scooters”’ is perfectly willing to sacrifice comfort for speed; but not the average Frenchman. He wants to sit on a backed seat instead of a saddle, and he likes to stretch his feet in front of him. The result? His motor- cycle is a strange affair. The wheels are very small and the body of the machine is close to the ground. The steering-post slopes toward the rider so that the handle- bars are easily within his reach as he sits back in comfort. The result is a motor- cycle rather than a scooter. One of these motorcycles is shown in the picture below. It will attain a speed of thirty- five miles an hour and eats up a little over a gallon of gasoline in that time. Oe ct atte aad Pm Erected in Memory of a Beloved Elephant N the photograph above a tower of un- usual design is shown. It stands near the deserted city of Fatehpur Sikri, British India, at one time the capital of the Mogul emperor Akbar, who ruled over a greater part of India from 1555 to 1603. The structure is known as the Hiram Minar, or Deer Tower, and it was erected by the Emperor Akbar in mem- ory of a favorite elephant that died on the spot now occupied by the tower. The monument is seventy-two feet high and is ornamented on the outside with hundreds of imitation elephant tusks. It is said to be the only monument erected to an elephant. It is not unsusal, however, for the inhabitants of Eastern countries to do honor to the elephant. In Siam it belongs only to the king. It is baptized, and fetes are given in its honor, and when one. dies, it is mourned for, just as we mourn for our loved ones. In India the natives have a great reverence for the elephant because of its intelligence, which to them seems uncanny. 37 Iron Pipe All in One Piece EW people realize what an important thing welding has grown to be. Today ‘ it has a thousand and one uses—all of °- them of great value to industry. Above is a gigantic iron pipe with an elbow that is made in one piece. This was made possible through welding. All the joints of the pipe are carefully welded to- gether, producing a single piece. The re- sulting pipe was so large and unwieldy that special means had to be provided for its transportation. This pipe was planned to be used to help’ in the canalization of natural streams in Germany. A few years ago the construction of such a large pipe would have been extremely difficult. A pipe like this is now made ina few weeks. Twenty years ago, it would have taken months to turn out such a job. Four Children at One Desk “Q MALL children are interested in each other; they are chummy,” says Mr. G. Rankin, a school director of Munhall, Pennsylvania. Whereupon he invents a chummy four, in the form of a desk. It is square, has four legs, and to each /eg a swinging stool is attached, which is spring supported and vertically adjustable for different sized children. Thus four chil- dren may sit at one desk. Besides the chummy element, this new desk takes up very little floor space, it 1s easily cleaned. A class of forty pupils arranged about these table-desks occupied less than three eighths of the space required when single desks were used.

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Popular Science Monthly es , - je — — - —_ = ins “ — _ ee nt aga al = 2 ~ te © Keystone View Company Into the Sea on a Bicycle ICYCLE riding, like any other sport, becomes mo- notonous in time. An Italian rider, however, has discovered a way to make it very exciting. He rides along the water-front, and whenever he sees a spring- board that is several feet above the watér, he rides right off it, straight for the water! His bicycle drops through the air, and as it goes he pedals rapidly. Thus, when it hits the water, he is able to keep it from sinking for a few seconds. He wears a life-saving suit, and in a short time he and his bicycle are back on shore, wet but happy. Ice-Skates Made of Bone ie the twelfth century steel was un- known. And yet the people of that time skated whenever there was ice. What were their skates made of? Bone. The leg bones of animals were used. They were tied to the feet by means of thongs, after being properly shaped and sharpened. Since the skaters were not able to make any speed on these skates, poles were used. © Kadel & Herbert Airplane Wings that Fold for Greater Speed za airplane is like a kite in this: it needs wing surface to rise from the ground. Hence all the big weight-carrying machines have large wings. On the other hand, large wings mean air-resistance in flight and a consequent reduction in speed. Airplane designers knew all this as soon as flying became practicable. They talked of reefing wings—wings that could be partially folded up in flight. Now comes a Frenchman who builds a machine with a wing that can be reduced in area. The big wing consists of three sections. The top and bottom sections can slide to a certain extent over the middle section. With full wing spread the speed is only thirty-seven miles an hour; with minimum spread, one hundred and twenty-four miles ~ an hour. Grandjean, the French aviator, made the test. © Keystone View Company Pumping Sand for the Engine WE are just learning how to make use of com- pressed air: every day brings a new application. The rail- roads are now making use of it in filling the sand domes of their locomotives. The sand is stored away in an air-tight cylinder in which a pressure is maintained. A pipe carries the sand to the dome, and the locomotive takes on sand in the same way that it takes on water. The fireman places the end of the pipe over the filling hole, opens the valve, and sand rushes in under pressure. It now takes seconds to fill a sand dome where it used to take minutes. To Photograph a Movie Battle yore is the angle of view afforded the moving-picture photographer when he takes to the air. But airplanes are too swift for “close-ups” and so it is necessary to make use of the ‘‘blimp.”’ Marshall Neilan, the director who staged “‘Custer’s Last Fight,’’ found that a gas-bag of 35,000 cubic feet, supplied by 200-pound metal containers, could be profitably em- ployed, even when it required two freight- cars to transport it 2200 miles to the scene of the battle. From the car of the blimp semaphore experts wigwagged the director’s instruc- tions to the actors on different parts of the field. In one case the “blimp” traveled slowly over the scene at thirty-five feet from the ground, obtaining “‘close-ups”’ of unbroken continuity. © Kadel & Herbert Popular Science Monthly Ma sen¢ lear sign nav outt SIX of t bes the rev¢ tion surf circ! key whe sent By keys grou T G see —tl stre nigh o’ el the | A The care Ame boal goes for t chile The toot drea . May, |

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it- ne ic- he ed ve ng ws May, 1921] Wireless Telegraphy with the Code Left Out T= learning of the Morse code is tedious. Here is a little automatic sender that obviates the necessity of learning the code. A Frenchman de- signed this apparatus for use in aerial navigation. The operation of the wireless outfit is reduced to the manipulation of the six keys. It is by pressing various combinations of these keys that different messages may be sent. A wind-driven distributor is placed on the front of the airplane. This is a revolving metal disk with proper combina- tions of dots and dashes mounted on its surface. From this point six electrical circuits run to the keyboard. When one key is pressed, a single dot is sent out; when two keys are pressed, two dots are sent out. The other keys represent dashes. By pressing the proper ccmbination of keys, the code signals may be sent to the ground stations. This Dentist’s Office Travels to the Patient (yee municipalities have always been models of fatherliness. They see to it—at least, they did before the war —that people behave themselves; that the streets are kept clean, that nobody makes night hideous with piano-playing after ten o’clock, and that everybody gets a seat in the street-cars. Apparently the system is still operating. The eity of Dortmund, for example, takes care of children’s teeth. To be sure, American cities do that, too, through their boards of health. Dortmund, however, goes farther than we do. It doesn’t wait for the children to turn up. It goes to the children with a dentist’s office on wheels. There is no escaping the tooth-yanking and tooth-filling process that boys and girls dread. © Kadel & Herbert He Fills His Suitcase with Light A SUITCASE full of incandescent lamps for the photographer’s lighting effects is a novelty. A stand supports the open case, and when the socket of the wire is attached to the house circuit a brilliant illumination suitable for photography in- doors is obtained. This is particularly convenient for “home photography,” where the subjects must be taken amid indoor surroundings, and where the ordinary illumination is usually poor. To prevent a harsh glare of light, a curtain of thin silk crepe is super- posed before the lamps. ..Chinese Eggs Shipped in Straw N America we ship eggs in crates, a very safe and economical way. The Chinese prefer to follow their ancient custom of shipping them in straw. A bird builds its nest of weeds and straw and that protects the eggs, so why not use straw as a means of packing them for shipment? Besides, wood is so scarce in China that wooden crates would be too expensive. So the Chinaman uses long straw beds, wherein the eggs are placed and separated by braided partitions of straw. The Airplane Engine Cooled in a New Way LAT radiators of the automobile type for airplanes are not the best for the purpose. When the airplane is flying at high speeds, the flat surface offers resistance tothe motion. Here is Lamblin’s radiator, which is worked out on new lines. This radiator can be placed anywhere. Its cylindrical form has many advantages. For instance, the cooling tubes containing water can be made long, narrow, and flat. The cooling air sweeps rapidly through the open cagelike device from one end to the other. Hollow tubes of thin sheet metal are used, and they come together at each end in a ring-shaped water-chamber. The water enters the rear chamber by pipe, flows through the different tubes, emerging at the front chamber, which has an offtake pipe. A second set of inwardly projecting tubes is also used. The outer tubes are connected by three small water-tubes that also bind the whole together. Caging the Corn to Foil the Greedy Rat ATS, traps, poisons, and ‘“‘other agents too numerous to mention”? have been used to fight the rats that infest corn-cribs and annually consume millions of bushels of corn intended as cattle-feed. Yet, with all this drastic war, the loss of corn due to rats has been increasing rather than diminishing. Little wonder that farmers are welcom- ing the “rat-proof corn-crib.’”’ It is made with sides of woven steel, a steel roof, steel floor, and steel doors. The crib comes in sections, ready to set up. All the farmer does is to lay a concrete foundation and erect the building on top of it. The cribs absolutely rat-proof, for rats cannot gnaw through steel nor climb up smooth steel surfaces. The crib is also fireproof and the corn keeps better in it. yy Ma Ys 1921

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Popular Science Monthly Across the Atlantic in a Forty-Five-Foot Boat After looping the North Atlantic, the tiny yacht weathered the worst of the winter’s heavy gales UR cruise in the Typhoon from Nova Scotia to England, and back to New York via France, Spain, and the Azores, was made pri- marily for the fun of the thing. There was no burning scientific conviction to justify it, By William Washburn Nutting knock-down that had put our mast- heads in the water, and, having come through this experience unscathed, our confidence in the design and construc- tion of our little ship was absolute. white. The long, gray, sweeping seas of the day before became confused irregular, and wickedly unstable. We were running under storm tri- sail, a small sail, heavily roped; and to make steering easie1 and to check our prog nor any thought of finan- cial gain. To be sure, there was an_ interna- tional motorboat race at Cowes on the tenth of August, and it was this we took as an objective; but, as far as we were concerned, we needed no excuse other than the one of sport. Picking your course across great stretches of ocean by your own (newly ac- quired) skill with the sextant, pitting your wits against the big honest What the Little Typhoon Did Ty phoon is a forty-five-foot auxiliary ketch, designed by William Atkin after suggestions by the writer, and built at Alexander Graham Bell’s laboratory in Nova Scotia. England on the eighteenth of last July, reach- ing Cowes in twenty-two days. New York in November, after a run of thirty- two days from Ponta Delgada in the Azores, where she had arrived from England via France and Spain. She sailed for She- reached ress as we shot down the slopes of the seas, we had put out a long line astern. But by mid- afternoon it was appar- ent that we could not carry even the trisail much longer. I was at the wheel. An occasional crest came over the quar- ter, flooding the cockpit and filling the slack of the trisail. Our speed was becoming dangerous. We put out a second line on the end of which was a large bucket; but even forces of nature, feeling your way with lead-line, possibly through fog and darkness, into strange places that the travelers of trodden paths never experience—these things, we think, are worth the time, the expense—yes, even the hardship and actual suffering—that are bound to be a part of any such undertaking. We don’t recommend taking chances with the North Atlantic in the middle of November, and we do not recom- mend crossing on the fiftieth parallel at any time of the year, as we did on our record passage to Cowes; but we hope that the small boat and its possibilities for cruising will come into its own. Weathering the Gale It was on the seventeenth of No- vember, the twenty-ninth day from Ponta Delgada, that the big blow came. Typhoon had _ weathered many a gale before in her seven thousand miles at sea—one off the Newfoundland coast, another in the Channel, and a blow near the Azores that sent eight American Shipping Board vessels into port for repairs. And we had just come through a two days’ ‘‘nor’easter’’ that we felt was the last word in weather. On the first day of this blow, running before it under full jib and mizzen, we had overtaken a three- masted schooner hove to, shot by her at fifty yards, photographed her, and left her wallowing astern. On the second day we had received a We felt that the Atlantic could do nothing further. But we were mis- taken. On the morning of the seventeenth, when the temperature indicated that we were drawing out of the Gulf Stream, the wind hauled around to the southwest and blew in a succession of hard punches, increasing in intensity until the sea was a driving mass of William Washburn Nutting, skipper of the Typhoon, the forty-five-foot ketch that last summer made a record trip under sail from Newfound- this failed to retard us sufficiently. I decided totry the sea-anchor, which we had never yet had occasion to use. What a Sea-Anchor Is Like The purpose of this device is to hold the ship’s head to the wind when conditions are too severe to carry sail. We brought it up from below, a great canvas bag, pyramid-shaped, with a mouth six feet square into which heavy wooden shears were fitted to hold it open. Huddled in the cockpit, we lashed the shears in place, made a pig of lead ballast fast to one of the arms, and then bent on the cable, land to the Scilly Isles in fifteen days 40 May, J hi we Vi. ‘Sb which a fair! order levers Wt and I life-li trisai mast, legs, the ec came weste pits. riggil big o agair embr sea-a the v the ¢ the \ and wate Burt Hi dow! little As t] loo’ an close hang I man was Jim and Ren I ye who F boa way dow the Dol to s thre ing wat

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y ot id- May, 1921 which previously had been led through a fairlead on the end of the bowsprit in order to obtain the extra seven feet of leverage. When everything was ready, Fox and Dorsett were instructed to put on life-lines and go forward to lower the trisail. Fox had reached the main- mast, to which he clung with arms and legs, and Dorsett had jumped out of the cockpit to join him, when a big sea came over us, jerking away my sou’- wester and burying Fox to his arm- pits. Dorsett, clinging to the mizzen rigging, shouted, ‘“‘That was a hell of a big one, skipper!’’ and started forward again along the waterway. Hookey, embracing the mizzenmast, held the sea-anchor from going overboard by the weight of his body. I crouched in the corner of the cockpit and clung to the wheel. Then the big crash came, and we went down under tons of solid water. Buried in Water—but Staggers Up How many seconds we were rolled down, I can’t say, but finally the good little ship staggered to her feet again. As the water poured off us, I looked to loo’ard and there, sixty feet away, in an acre of froth, was Jim Dorsett’s close-cropped head, his sou’wester hanging from its string around his neck. I realized that it was impossible to maneuver the yacht in such a sea. It was equally impossible to swim for Jim in sea-boots and heavy oilskins, and there was no time to take them off. Remembering the lines trailing astern, I yelled and gesticulated to Dorsett, who made for them. Fox also had been washed over- board, but he had regained the ship by way of the mainmast which had come down on top of him. He now lowered the trisail. As we reeled down past Dorsett under bare poles, he managed to seize one of the lines, but it slipped through his grasp. It was an agoniz- ing moment for us on the Typhoon, watching him, now under water, now Jim was overboard! How many seconds we were rolled down, I can’t say, but finally the good little ship staggered to her feet again. We could see Jim’s close-cropped head in an acre of froth, his sou’- wester hanging from its string around his neck visible and each time farther from the ship. The line to which he clung was not the one with the _ bucket, and I feared that every moment he would reach the end; but finally, turning on his back, he was able to hold fast, and we got himin. With the aid of a boat-hook we pried him higher. Then we got a leg over the gunwale and I determined that at least we would have that leg. Finally after more tugging, he was aboard. The Sea-Anchor Line Parts Passing Dorsett below, we turned him over to Dillaway, who had been battened down in the cabin through the ordeal, and prepared to throw over the sea-anchor. I had theories about sea-anchors, but 1 was not at all certain that it would be possible to hold Typhoon’s high bow to the seas without some bit of sail aft to act as a weather- vane. Asa precaution, we had brought out our little spitfire jib, which is mounted on a steel luff-rope, so that in case the sea-anchor proved insuffi- 41 cient we could hoist it on the mizzen and trim it flat. Finally we got the bag overboard, but I can’t say just how effective it would have been; for as the strain came on the line it parted like a piece of twine and we were leftlin the trough. Then I realized that, for the ten minutes or so that had elapsed since the knockdown, Typhoon had taken care of herself perfectly in spite of the seas that crashed aboard. So, leaving her to her own devices, we went below, drew the companion hatch, opened a bottle of cognac, sang some songs, and turnedin. And came through without mishap. In weathering the blow that delayed the Aquitania and wrung the S.O.S. from many a giant ship, Typhoon proved that a small boat can be as seaworthy as a big one.

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By installing gigantic machinery in railroad yards it is possible to unload grain by the simple operation of tipping Unload the Car by Tipping OUR machines for unloading grain from railroad-cars to grain elevators have been installed in a new Penn- sylvania railroad elevator at Balti- more. An operation that it took four men forty-five minutes to accomplish can now be done in ten minutes by three men. : When a car is hauled into position by a “barney” elevating arrangement, it is clamped in place on a tipping table erected on a cradle. The tipping table tips the car longitudinally, 30 degrees, while the cradle tips it end- wise 45 degrees, first one end up and then the other. Another feature of the machine is a “‘door-opener,”’ which pushes the door of the car, filled to the brim with grain, backward without breaking it, and is equipped with a ‘“*hopper”’ into which the grain drops. Underneath there are traveling belts that convey the grain into the bins. Peach-Stones as a Substitute for Coal EACH-STONES—all during the war we saved our peach-stones and dropped them in barrels that were placed in convenient spots. Some of the stones were subsequently used in making gas-masks. But many tons of them were left over when the war ended. What’s to be done with them? Use them for fuel, says the New York Coal Exchange Peach-stones have about 80 per cent of the heating value of coal. And they are being sold now at one dollar per ton! With coal both searce and expensive, it is expected that peach- stones will become very popular. They can be used in the furnace, in the kitchen stove, and in the parlor grate. other. seems ridiculous. working? Mi Se f- y By switching the fire from room to room, one can snatch a few minutes’ rest Popular Science Monthiy One Stove Heats Four Rooms O carry a small gas or oil stove is an easy mat- ter when you want to heat first one room and then an- To take a glowing fireplace from room to room But why should a whole house be heated, when all that con- cerns you at the moment is the one room in which you happen to be sitting or Besides, coal is expensive these days, and never too plentiful. P. B. Martyn, of Airdrie, Seotland, solved the prob- lem to suit himself by in- venting a concrete cylindri- cal chimney into which js fitted a rotatable cylinder con- taining four fireplaces. the center of the house where all of the four rooms meet. Mr. Martyn places the stove within the chimney, and turns it so that the heat is radiated by the fireplace of the one The clever idea of a Scot for revolving the fireplace to the spot where it is most needed throughout the day The chimney occupies a place in room that needs warming. There are many days when a warm fire in the grate will take away the keen edge of the frosty air. Once the room is heated it will remain com- fortable for a long time. On such occasions the whole house can be heated with the use of a single fire- place, thus saving three fires and the coal they would consume. Brackets on the side of the fireplace conveniently hold the kettle of hot water and the teapot. Thus the domestic hot-water supply is switched around to the room where the after- noon tea is to be served. On a very cold day all of the fireplaces may be used simultaneously. Digging Trenches Eight Feet a Minute UCKETS whirl around and dirt flies! With this digger, a trench about one foot wide and four and one half feet deep may be dug for a distance of eight feet every minute. The buckets are on a circular frame that bring them in contact with the earth. They bite in and fill them- selves. When they reach the top of the frame, they are inverted and their contents fall on to a chute and slide into a wagon. Two large sheet-iron plates follow the cutter wheel to prevent the banks from falling in. The cutter wheel is turned by the powerful gas engine placed on the front that gives the machine such an old-fashioned look. The buckets on this circular frame bite into the earth, fill themselves, and when they reach the top, they are inverted and empty themselves 42 hov the wir tau Fol dru are vio ma go the kin Dr diff rev sid she the stil ser the aff exe me thi the pla “'teé sul im] wa the soo an sm rar rat the

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e yt 1e r- ye ir le May, 1921 Learning to Crate and Box in School F you want to learn how to box and crate, what kind of wood is best, how to nail the crates or boxes to make them strong, how to strap, to bind, or wire the boxes, go to school and be taught. In this school (that of the Forest Products laboratory) is a large drum into which various kinds of boxes are put and thrown about with a violence that no truck-driver could match. Students watch the material go to pieces under the strain. Then they learn how to make the strongest kind of boxes and crates for shipping. One subject is studied each day. Drop tests are made to show failures of different types of boxes; drum tests reveal the behavior of pieces on the sides and ends. Tests are made to show the relative holding power of These men are learning to box and crate. When different kinds of nails, and the effect of using green lumber for boxes. Then the various methods of strapping are illustrated, and the influence of the grade of lumber is shown. The student leaves the school knowing how to send freight safely and economically. But why is this so important a subject worthy of so much at- tention? In 1919 one group of railroads expended just $103,078,862 for lost and damaged freight. In one month twelve Western cities re- fused or repaired 43,738 packages. It is estimated that there is a daily loss to shippers and manu- facturers of at least $500,000. their six-day course is finished, they will help save millions of dollars a year Broken Limbs Exercised in Bed VERY important detail, in treating fractures, especially those of the thigh, is that of preventing stiff joints. Exercises are usually pre- scribed, but these are carried on after the patient has left his bed, when the affected area is so stiff as to make exercise very painful. Dr. O. Ansinn has recenly devised a means of giving exercises in bed, before this stiffness becomes pronounced. In the case of a broken leg, the limb is placed, not in plaster-of-paris, but in a “tension” dressing, on a jointed plank support, which, when manipulated, imparts to the leg all the motions of walking. The first time this apparatus is used, the nurse operates it; but the patient soon learns how to work it himself. Dr. Ansinn has in addition invented an automatic apparatus actuated by a small electric motor or by a hydraulic ram. The patient himself controls the rate of speed as well as the starting and the stopping of the apparatus. He himself manipulates the motor that works the apparatus for exercising his broken leg 43 Siamese dances inspired Florence Meehan to make this little dancing figure She Dances to Anything the Record Plays HE latest phonograph novelty is a dancer who illustrates the record as it plays a dance. About a year ago, Florence Burgess Meehan, of Chicago, saw the native dances as they were performed for her in the palace of the King of Cambodia. She had many pictures made of these-dancers. In Java she found a Malay workman who was able to make reproductions of the dancers. This model she brought back to America, and worked out a model that could be operated by hand. Then the idea of placing it on a talking-machine suggested itself, and now it is possible to witness a Siamese dance while listening to any dance record. A jointed lever connects the small wire passing through the head with a wheel that touches the record. As the record turns, the lever moves. Another notched wheel connects with another lever connected with the body. This makes the figure dance. Seventy Pounds of Meteor Every Day UR planet is getting heavier and heavier! How does that happen? Because of the meteors that are con- stantly falling on it. You may not have seen any of them fall, but the earth isalarge place. Ina year eleven thousand four hundred and thirty-five tons of meteors fall! This gives an average of seventy pounds per minute. Much of this tonnage comes in the form of fine meteoric dust that settles all over the earth. However, a large meteor—too big to burn on entering our atmosphere—falls occasionally. Several years ago one of them fell in Iowa and exploded on hitting the earth. Over five thousand pieces were picked up and some weighed over four hundred pounds.

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Popular Science Monthly » May, The New Art of Self-Defense _ Mental, physical, and moral perfection is the purpose of Professor Jigoro Kano, who has improved jiu-jitsu into jiudo A man standing evenly bal- Learn how to trip your man anced on both feet is like an —that, too, is part of Pro- upright pillar. A push—and fessor Kano’s new art of he is down jiudo ; : P ‘ When an opponent seizes your When one or both hands are held wrists, how would you break his down, free them simply by a quick hold? See the next picture upward movement The finger-tips are weak. This is a good reason for making your opponent use them ® soem sae It’s no use trying to upset a much heavier man. What’s the solution? See the picture on the right. When the weaker man, keeping his own balance, pulls the stronger forward, using only part of his strength, he reduces the odds against him. Re- taining half his own strength he has the advantage over his opponent A quick pull and a quick } as turn around your hip and your opponent is unbalanced and thrown. And then—but see the picture at the right. Then he is easily tossed over on his head ee | When an opponent strikes with his right arm extended and his right leg forward, strangle him by pulling him : forward and twisting him around The picture on the left shows aman trying to give a swing- ing blow from the side; in that case you duck and grab his arm. The blow is warded off and the opponent is pulled out of balance. At 44 the same time, by a quick upward movement of the leg and by falling down, the op ponent is pitched over your head so that he comes down on his back—see the picture on the right Pamlae Saence Mamthl,, a =

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a May, 1921 Running a Circus by Motor ae teat wet hh 4 mh | a * bh) jie te ih ee % ) af a an e.. This clown is one of the “live” actors, caught in the act of welcoming the public to the circus Clown pantomime in real life adds to the interest of the mechanical circus, but when the motor is started and the dummy performers begin to do their acts on the stage, the live clowns step aside Here are some more living members of the motor-run circus. The entertainment had a long run in one of New York’s big department-stores, where it was exhibited free daily This circus is operated by electricity. There are thirty-eight near-life-size figures — jugglers, clowns, tightrope walkers — and eighteen acts of a real circus. The show was built by W. F. Larkin, of the Wanamaker _ store, New York Before the motor is start- ed that operates this cir- cus, a procession of clev- erly made-up clowns takes place. So lifelike are the dummy actors that one might suspect the living actors in the procession of being opera- ted by motor 45

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(area =. oe Making a Mailbox Out of a Barrel GO peers his inventive genius, a farmer took a barrel, an old dish-pan, and a forked limb, and made himself a mailbox to protect packages from the weather. The end of the barrel was first knocked out and a piece of the side wall! of the dish- pan was cut to fit over the opening in the barrel to act as a protection against rain. The end of the forked post was put in a hole and tamped in to make it solid, and the barrel nailed between the forks. A piece of the barrel-end was nailed on top of the barrel on which is written the owner’s name and rural route number. The Machine Rotates and Plates E use many things in our daily lives that are electroplated with nickel, copper, silver, or gold. The plating- machine shown below will help to speed up production and make cheaper the plated things we buy. The parts to be plated are hung from a metal wheel that revolves in the center of a series of anodes. The anodes are revolved in the opposite direction. This arrangement allows a higher current to be used, and the heavier the current is, the more metal may be deposited within a certain time limit Catching Fish in New Guinea with a Spider’s Web reer spin their webs with the object of catching flies and other delectable insects. If a spider could speak, he would * doubtless tell you that it is a long, tedious job, but worth while in the end. Imagine the feelings of the spider of New Guinea when he returns to his web and finds it gone—stolen by cannibals! Mr. Spider hears a splashing in the brook near by. He goes down, and there he sees a woolly-headed man-eater catching fish with the web he had so carefully spun but a few hours before. In New Guinea the spiders are as large as hazel-nuts, and they have great hairy dark-brown legs about two inches long. The webs they spin are often six feet in diameter and are very strong. The natives soon found this out, and they set up long bamboo sticks, looped at the end, in places where the webs were thickest. When the natives returned next day, their fishing-nets were ready for them—several unsuspecting spiders having spun their webs on the bamboo loops. Popular Science Monthly With This Plow a Horse Is Not Necessary 8 pet you ever hold down a horse-drawn plow? It is real work. Here is a one-man plow invented by a German who had some plowing to do, but who did not have a horse. In fact, his little plot of ground was so small that the use of a horse was not worth while. That was just what made his invention practical. It can be used to cultivate small pieces of ground. The one-man plow works with a lever action. When the lever is pushed forward, the plow-blades dig in and also move forward. Radio Messages Between Cities As Avon THOMPSON of Chicago sends a radio message to Mayor Hylan of New York. Within twelve minutes’ time the message is placed on Mayor Hylan’s desk. It would take a much longer time to establish telephone connection. Radio works fast. That is why the cities of New York, Cleveland, Detroit, and Chicago decided to carry on their official business by radio. This rapid service is carried at a smal! expense, and no time is lost waiting for an “open” wire. It may not be long before all of our large cities are ‘‘connected”’ by radio. © Underwood & Underwood M ays 19: ———=—— io = a ban. , Ce! CE) this The ce tues of | business braska, | and oth made no ment thi: hogs are The t1 portunit for prote blasts al sunshine Gi NE ce sight a ball, a putter, sightin ford, o By r dial on head, justed locked thumb use, th and ca the pl lowed elemer the pr be ma howev this p mittec

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May, 1921 Ha iz we Cement Wallows for Pigs CEMENT structure is the home of this family of hogs. The cement piggery emphasizes the vir- tues of sunshine and cleanliness in the business of raising hogs. Iowa, Ne- braska, Kansas, Missouri, Ohio, Indiana, and other pork-producing centers have made notable progress in providing equip- ment that would explode the theory that hogs are simply born filthy. The truth is that hogs are given no op- portunity to be clean. Comfortable barns for protection during the nights of chilling blasts and sanitary wallows for days of sunshine, constitute a well ordered piggery. Golfers Use Sighting-Rod on a Putter (= of the chief requirements for suc- cessful ‘‘putting’’ in golf is to aline or sight accurately the head of the putter, the ball, and the hole. Above you see a putter, to which is attached an adjustable sighting-rod, invented by Edward Hart- ford, of Deal, New Jersey. By means of a graduated dial on the top of the club- head, the rod can be ad- justed to any angle and locked in position by a thumbscrew. When not in use, the rod can be removed and carried in the handle of the putter, which is_hol- lowed out. The sighting element is so designed that the proper club balance will be maintained. We doubt, however, whether the use of this putter would be per- mitted in most golf clubs. Increase the Efficiency of the Lawn-Mower VERY man who cuts his own grass will be interested in a lawn-mower, for which the inventor claims that it will cut grass more easily. Its cutting edges are longer than those of the ordinary lawn- mower, although they do not require any more space. This feature is made possible by crimping the cutting edges. “Tt will cut easier and handle taller grass,’’ the inventor claims, but he fails to mention how he would sharpen the blades. Marines on a Goat-Hunt O densely populated with goats had a part of Catalina Island, California, be- come, that they were a menace. The farmers recently appealed to the commander of the Pacific fleet for help, and he detailed a squad of marines to attack the goat enemy. In a three-day fight nearly six hundred goats were killed, and a number of mascots were captured for ships of the fleet. It is said that many thousands of dollars were saved through the cooperation of the marines. 47 Gather Corn by Machine HE mechanical picker is a_labor- saving device, first introduced in the states of Illinois, Indiana, and Iowa. This picker plucks the ears of corn from the upstanding stalks and deposits the grain in a wagon that keeps pace with the machine. Old men or boys can operate it. Three men and three teams can cover seven acres in a ten-hour day. Two wagons accompany each picker, one unloading while the other is being loaded. By covering seven acres a day, each acre yielding fifty bushels, the machine harvests 350 bushels. Courtesy of the American Bible Society Reading with the Tip of the Tongue \ ILLIAM McPHERSON was super- intendent of a large stone quarry in Colorado. A blast, for which he was not prepared, blinded him and blew off both his hands. Confined in solitude, McPherson suffered only as one used to activity can suffer—until he heard of a blind woman who had discovered that when she kissed the Bible she could discern the raised letters with her lips. This gave him an idea. A friend taught him the alphabet in raised letters that he could read with his tongue. A frame holding a Bible with embossed words has a shelf arranged with pulleys, so that a mere touch of the elbow is sufficient to raise or lower it.

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Popular Science Monthly This Purse Looks Like a Book URING the “crime -wave,” anything that iooks like a pocket-book is attractive to the eyes of the purse-snatcher. Hence the ruse of a genuine book to camouflage the pocket- book. The covers of a volume may hold memorandum leaves, or they may merely enclose an open space in which bills are carried. In his search for money the thief will probably respect such an_ innocent-looking object as a mere book. Here Goes a ‘‘Monocar,’’ a One-Seated Motor "T“HE vehicle illustrated below represents an attempt on the part of Brown and Roper, young English engineers, to solve the problem of a single-seated vehicle with the comfort and protection afforded by a car that has all the handiness and economy of upkeep of a motorcycle. Starting with the idea cof evolving some- thing different from the ordinary motor- cycle, the inventors have achieved a ma- chine that has all the stability of a car at slow speed. Two small trailer wheels are provided for use in slow city traffic, but on the open road a touch of a lever lifts these trailer wheels and full speed is available. The front wheel is steered by means of parallel reins attached to the steering-head. A spring seat is placed low, aft of the gasoline-tank; and the feet of the driver rest on comfortable spring footboards. Make a Lobster Stand on Its Head NDER the hard shel! of the lobster’s bac! are exceedingly sensitiv: nerve centers. When thi part of the shell, the “cara pace,” is stroked or rappe: with a stick a hypnoti state is induced. The effect is probably similar to tiring the retina and optic nerve of the hu- man eye by keeping a per son that is to be hypno tized looking steadily at 2 bright object. Apparently a lobster i always willing. When he is thus subdued, he can be stood head downward and will stay that way for five or six minutes. Wooden Pipes Are Still Used ITH the increased use of concrete, steel, and tile pipe, it is difficult to believe that large wooden pipes are still able to offer competition. One thing is in their favor, among others, and that is resistance to the influence of heat and cold. Blistering heat or biting cold does not affect them in the least. This big forty-two-inch wooden pipe looks like a huge snake stretching itself across the prairie. It acts as a siphon in the Sunnyside Project of the United States Reclamation Service. Many of these big pipes are made of California redwood. This wood is fast disappearing, and before long the manu- facturers of wooden pipe will have to be satisfied with cheaper wood. The Wisdom of the Sparrow bf she early in the spring, before the leaves are fully grown on the trees, the house sparrows build their nests. Thus the nests are plainly visible to passers-by. A few years ago Washington declared war on these birds, and as a result the nests were ruthlessly torn down. Nets were thrown over vine-covered walls and the luckless birds within were captured. Did this persecution scare off the birds? Not at all. The following year they were back again—but not a nest was to be found! They built their homes outside the city. Japan’s Greeting to the New Year ie Japan this is the year 2581, and it belongs to the tenth year of the period entitled Taisho. On the day that marks the beginning of the new year, the Japanese children put on fantastic masks and have as much fun outdoors as do the children of any American city on Thanksgiving Day or Hallowe’en. The Japanese masks are grotesque and look clumsy; but they are made of paper -and are therefore light. The curious quality of these masks is in the work of the color artist. But Japan is a country of artists, and whatever the Japanese do is managed from the viewpoint of how it will look. Symbolism also plays an _ important part in the masks. They represent the figures of tradition, and many have a special meaning, other than just being grotesque. Ponylar Seience Monthira M% } H yest sp States vey m with a of the x the mo at whi ever | mainta expert climb entails in 4 diffieul cided large t year’s aleale but pl install Tipy W. can br and ti in fift So1 cars 0 six-ho the ¢ When perfe pushe car is turnil

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ee ok May, 1921 The Largest Rain-Gage N OUNT WAIALEALE, of Kaui, i Hawaiian Islands, is the rain- jest spot on earth. The United States Geological Sur- vey measured the rainfall with a gage. The summit of the mountain is probably the most inaccessible place at which a rain-gage has ever been installed and maintained. Only the most expert mountaineers can climb to it, and the visit entails a three-day trip. In order to meet this difficulty, the Survey de- cided to install a gage so large that it would hold a year’s rainfall. The gage placed on Wai- aleale in 1910 had a capacity of 600 inches, but proved too small. The present gage, installed in 1920, holds 900 inches. Tipping the Whole Freight-Car bP dhe place three men in a car to shovel out coal, when the entire car can be clamped in a frame, given a twist, and turned over? A day’s work is finished in fifteen minutes. So rapidly does this tipper work that ten cars of coal can be handled in one hour. A six-horsepower motor turns the tipper, and the coal falls into the big bins below. When the car is righted, the rails are in perfect alinement and the car is pulled or pushed away to the “empty” track. The car is clamped to the tipper during the turning. headlights. At Four, He Owns His Own Sedan RWIN KRESSER, Jr., isfour years old, and he owns a sedan car that fits him snugly. motive power, it is exactly like a large sedan. Irwin has to pedal in order to make his ear go. There are headlights, lights on the dashboard, an electric heater, a speedometer, brakes, a horn, a winter top, and a summer top. another person besides the driver. The body and the disk wheels are made of aluminum; tin drinking-cups painted black serve as The car is three feet high, six feet long, - and will make a speed of three miles an hour if the driver pedals as fast as he can. The joys experienced by the driver of a flivver when he passes a high-powered car are nothing to Irwin’s as he tries to keep up with his father’s car. Five Years of Fires EARLY a billion and a half dollars’ 4 worth of property has been destroyed by fire in the United States during the last five years. New York state is the chief sufferer, her losses being a tenth of the total. Pennsylvania comes next with a loss half as big as New York’s. Illinois is third, New Jersey fourth, and Massa- chusetts fifth. What are the chief causes of this tre- mendous waste? Statistics show that de- fective electric wiring heads the list; next comes matches—smoking (do the ‘‘antis’”’ know that?); and the third cause is de- fective flues and chimneys. Stoves, fur- naces, boilers and pipes, lightning, spon- taneous combustion, sparks on roofs, and petroleum all help the bad work along. Except for the There is room for Baby-Carriages for Fishers HERE is a man in Redondo, California, who wheels a peram- bulator to the dock every time he goes fishing. Minding the baby while he waits for a bite? No; his perambulator contains fishing tackle and assorted bait, arranged neatly in drawers and on shelves. There is no child present. At the front of the per- ambulator there is a seat on which the fisherman sits while he angles for small fish. At the back of the perambulator there is a bracket that holds a large fishing-pole set for large fish. A small cement garage houses the peram- bulator when it is not being used. There is a drop-door to the garage, which when let down serves as a runway. Off with the Barnacles! VERY year millions of dollars are spent scraping the barnacles off ocean-going vessels. Inventors have long striven with the problem of removing barnacles by machine without taking the ship out of water. At last a machine that appears to have some promise has been developed. A long revolving brush, with wire bristles, is lowered into the water and brought in touch with the ship’s sides. This is driven by powerful electric motors that are thoroughly protected from the water. When the brush revolves, barnacles fly.

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Popular Science Monthiy Not Grass but Green Concrete I ATHER than struggle with lawn- mowers, weeds, and worms, Mrs. Woodward, of Los Angeles, had a con- crete lawn built around her house. It is painted grass green, and from a distance it can not be distinguished from real grass. What is more, the concrete is perfectly smooth and makes a good outdoor dance floor. The concrete lawn needs very little attention—just a coat of paint once a year and an occasional washing. There are circular openings in it, and real flowers are planted in them. One Reason for Oil Shortage? ( IL-BURNING vessels to the number of 635 were in use in the United States in the year 1920. Has the increasing use of oil on vessels had anything to do with the recent acute shortage at Atlantic coast ports? It has been suggested that in order to conserve oil for use in the merchant marine, where it shows great savings in greater dead-weight capacity, it would be a good plan to dis- courage stationary plants from using it. Although He’s Blind He Runs His Own Drug-Store HIS blinded soldier manages to run his own drug-store and make a comfortable living without having had to learn a new trade. How does he know the difference between a bottle of sulphuric acid and a bottle of toilet-water? He does not need to smell them; he uses the Braille system of raised letters. Every bottle, and the various com-: partments containing the different articles dispensed by a druggist, are labeled with Braille letters. © Underwood & Underwood aa" Rackets of Laminated Wood UITABLE material from which to manufacture tennis-racket frames is becoming scarce and there is a consequent increase in the percentage of bad rackets. The Forest Products Laboratory at Madi- son, Wisconsin, has been working on a method of building rackets entirely of veneer. The picture shows several steps in the manufacture of these frames. The veneer is glued in wide strips, including cross- banding of a darker-colored wood that appears as dark stripes on the frame when the large piece is cut into sections. From this point the process of manufacture is the same as for solid construction. Your Skin Tells Your Age NE way to tell whether you are getting old is to hold the back of your hand with its fingers outstretched and with the other hand pull up the skin. If it quickly snaps back into place, you are young. If it comes down slowly and stays puckered in a ridge, you are old, no matter how few the trips you have made around the sun. “One is as old as his skin,’’ because the skin is kept in health by the gland in the neck known as the “‘thyroid.’”’ To this gland the blood goes to be relieved of cer- tain poisons. © Keystone View Company The St. Lawrence Boat Store “PD ANKRUPT merchandise legally stolen from all parts of the U.S.A.” This startling announcement is painted along the side of a boat that travels the St. Lawrence river. Pirates on board? No; honest men who buy merchandise at bankrupt and auction sales and sell it cheap. Their boat is their store. This boat is towed from place to place. In summer it is usually around the Thousand Islands; in winter near Ogdensburg, New York. The inside is fitted up like a store. Controlling Humidity in Shops ‘ A N apparatus for the “conditioning” of 4 air in shops has been evolved by the Forest Products Laboratory at Madison, Wisconsin. It consists of a small cabinet in which water-sprays suck in the air, cool it, and moisten it. All this is preparatory to bringing the air to the temperature desired. This is done as the air leaves the chamber, by a coil, the steam supply of which is controlled by a thermostat located at the outlet. Can You Concentrate on Five Things at One Time? ERE is an apparatus that decides whether you can concentrate your mind on several things at once. It com- prises five U-tubes of mercury, which is made to rise and fall at a variable rhythm. The subject must control the mercury in the tubes to keep it level. To do this, one must concentrate on five different im- pressions at once. The subject keeps his hands on five knobs, each corresponding to a tube, and when the mercury rises beyond the mark, he presses down that tube’s knob, withdraw- ing his hand when the mercury moves.

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May, 1921 Carry Your Table to the Picnic (= you a motorist, an engineer, a \ camper, a nurse? Then you will ,doubtedly be interested in the folding .ble invented by P. J. Risdon. It is ry light in weight and when not in use ill fold up into an oblong package that easures fourteen by thirty by one and half inches. When it is opened, this table is five feet long and will accommodate several people. The legs of the table have spikes their ends that sink into the ground ind give the table firm support. Thus t is very useful for serving meals out- aoors. In a hospital, the table will span a patient’s bed so that it can be used for eating, writing, and supporting books, nd is especially useful during the trying riod of convalescence. Famous Brains Now Shelved N the Museum of the School of Medicine, in Paris, can be seen a number of models of distinguished brains. Note the mold on the second shelf from the top, the second from the left. It is the brain of the famous scientist Berthelot. Within its convolutions originated the meth- od of proving that organic compounds, such as fats, sugars, and other substanees, could be synthetically produced without the inter- vention of some mysterious vital activity. Next is the brain of Gambetta, the famous French statesman, while on the same shelf, the fourth from the left, is the mold of the brain of Troppman, a noted French criminal. Courtesy of the American Museum of Natural History Is This Frog Blowing Bubbles? ‘Ts little green ‘‘spring peeper’’ that lives in the marshes of Long Island sends out his voice so loud at night that it can be heard half a mile. The photograph above, by Dr. Frank Overton, of the American Museum of Natural History, was ob- tained by flashlight. The frog in- flates a thin membrane in his throat, and this serves to intensify the sound. The pouch is inflated through small openings in the frog’s mouth. There are other frogs that use this “resonator,”’ and the sounds vary from a coarse ker-r-raw, to a note that equals the bluebird’s song. Removing Moss from Canals HEN moss grows in canals, it “soon causes trouble. Yet how to remove it? George E. Stratton, of the United States Reclamation Service, offers several sug- gestions. If there is plenty of time, the canal can be dried out; the sun will kill the mossy growth. When the moss is stiff, submarine saws will cut it. Dragging the bottom with a harrow is sometimes resorted to, but a chain is more effective. Thirty-three miles of canal were dragged with a chain at a cost of nine dollars a mile. Keeping the Grinding-Wheels Continuously Wet HOWN below is a grinding machine equipped with a small pump that pours a stream of kerosene on the cutting surfaces of the three wheels. This tends to keep the tools cool and save them from wear. High-speed tool steel is very easily “burnt” if it is allowed to remain in contact with the grinding-wheel too long. When kerosene or water is used to keep the tool cool, grinding is facili- tated and all danger of damaging the tool is avoided. The kerosene runs off the wheels into a big pan, where it is again picked up by the pump and forced back into the piping system. Three wheels are used on the machine, one for coarse work, one for medium, and one for fine work. Into the Hippo’s Mouth © tees “Mogul,” a hippopotamus long a resident in New York’s Central Park Zoo, was wild and fierce. He thought nothing of overturning hunters’ boats as an interlude to his morning’s bath, and if the hunters waited long enough, he would finish their adventures then and there. But Mogul has reformed since then. He is now a proud exhibit of the keepers. The picture tells its own story of their con- fidence in his gentleness. Nevertheless, when this particular keeper was preparing for his sensational act before the camera, he instructed quick.”’ our photographer to ‘shoot

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Popular Science Monthly Hats of Wood and Paper They appear just as attractive as the more expensive spring hats Why pay twenty-five dollars for a hat when you can get one for twenty-five cents? A cardboard frame covered with crepe-paper and trimmed with paper fruit will develop into a pretty hat that costs but a quarter © Kadel & Herbert © Kadel & Herbert ’Tis fortunate for this young woman that Hansel and Gretel lived long ago; for her hat is made of candy. We hope it doesn’t grow sticky when the sun shines on it ‘Don’t sell your old newspapers to the junkman,”’ says Miss Arcadie Fleming, of Dover, Delaware. “They make excel- lent dresses and hats.’’ She is shown here wearing’ her newspaper hat © Kz sol me sal hi str ha gre for © Kadel & Herbert Yellow pine shavings were shaped and given a coat of milliners’ var- nish. They make a very becoming hat, and look, at first glance, like gold- colored velvet As long as the aristolo- chia vine blooms, this girl will have a new hat every day. She plucks one of the large leaves, turns it upside down, and drapes it on her head Crepe-paper hats come in all styles. They may be stiff and tailored, or profusely ruffled—and they cost only a quarter or so! \ t ¢ \ I t I . a I

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May, 1921 E © Kadel & Herbert Here you see a_ blind soldier. His dog — for- merly an idler—has for- saken a life of ease to lead him safely through city streets. The dog wears a harness to which a handle is attached; the master grasps it firmly as the dog forges ahead Kadel & Herbert Dog’s Life Dogdom has its laborers and its idle rich just as humanity has He does so much motoring, you know. Fearful strain on the eyes; hence the spectacles ce ie see Sai op © Kadel & Herbert Why does this dog carry a parasol? Not to protect his complexion from the sun, as one might suppose he does it for business S reasons. Advertisements are painted on the parasol and on the dog’s jacket; he is paid a regular salary for parading through the streets each day A sudden rise to fortune often affects one queerly. This dog, res- cued from the streets by a theat- rical man, is now a star, and he finds he must be manicured at least once a week What is one horsepower equal to? In this case it equals one dog- plus one man-power. When the horse that formerly hauled the cart passed into the beyond, his master could not afford another. He har- nessed his dog to one shaft and carried the other one himself © Kadel & Herbert This dog knows ship’s time as ‘‘bells.”” He rings the hours and half-hours by pulling the bell-rope with his teeth Here’s a dog that hears more music in a day than the operator in a moving-picture theater. He draws a street organ around town and stops in every block; the minute he stops the music starts. Surely there are some days when he feels like breaking loose Hy Kadel & Herbert

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Popular Science Monthig; with a crash. dollars to fell this stack T would be exciting to see a 210-foot concrete stack, weighing two hun- dred tons, fall to the ground with a crash. That is what happened in the city of Spokane. The city engineers were called upon to bring the stack to the ground, and a short time after the order was received two hundred tons of concrete and steel lay sprawled out, a bent and broken mass. A new building had been erected a short distance away. If the stack had been allowed to fall on this, great damage would have been wrought. On the other hand, if the stack fell to the south, several thousand dollars’ damage would have been done to the Two hundred tons of concrete and steel brought down It cost two hundred and fifty-four down. It was a tough job to bring this big concrete stack Sixty-five holes had to be drilled in its base on the side toward which it was to fall How They Felled Spokane’s 210-Foot Stack railroad property. fall “just right.” Before work was started to weaken the base of the stack, an attempt was made to attach a heavy rope to the top. A gun to shoot the rope over, used by the fire department, was pressed into service, but the height was too great. A light scaffold one hundred feet high was built inside the stack. A hole was cut through the concrete, and a heavy anchor carrying a three-quarter-inch cable was hoisted. This was connected with a windlass on the ground, which could exert a pull of twenty tons. The workmen then hacked at the It simply had to base of the stack with their chisels and hammers. They drilled sixty-five holes around the base on the side toward which it was to fall. Several small charges of dynamite were then put in place and exploded. The stack listed several inches, but refused to fall. A hurry-up call was sent in for oxyacetylene torches. The exposed steel ribs were cut. Still the stack insisted on standing. Another charge of dynamite was set off. This was the last straw. The great mass of concrete and steel started to sway. Slowly, then with increased speed, the stack moved earthward. There was a crash and all was quiet. Electromagnetic Clutch Regulates Its Own Power WO Englishmen, Messrs. Davies and Soames of London, are the in- ventors of an ingenious electromagnetic clutch that can be used automatically to regulate the electrical output of a generator or the mechanical driving power of a motor. There is no me- chanical connection between the driv- ing and driven parts of the clutch only magnetic attraction, the extent of the magnetic force exerted being in proportion to the electric current passed through the electromagnetic coils. The device is particularly valuable in instances where the generator of a motor- generator set is suddenly overloaded or short-circuited. Under such an extreme con- dition, the clutch has its mag- netic pull automatically cut down, so that there is slip- ping between the driving and driven parts, preventing damage to the generator windings. It is therefore very desirable for machinery that is subject to sudden overloads or shocks that would burn out or otherwise damage electrical units not equipped with the clutch. The clutch could also be used to pro- tect machinery likely to be jammed, such as anchor-winches, capstans, and winding drums. Briefly, the clutch has two main coils, one in the driving member and the other in the driven member of the MAGNETIC COILS 54 The clutch has two main coils, one in the driving mem- ber and the other in the driven member of the mechan- ism; the driving member’s coil attracts the other mechanism. Initially only the driving member’s coil is energized, thus at- tracting the driven part magnetically and pulling it around with it. Sup- pose the clutch is used for a connect- ing-link between the shaft of an electric motor and that of a generator. As soon as current is taken from the generator—that is, as soon as some electrical load is put on it—the coil in the driven part of the clutch is energized also. This has the effect of opposing the magnetic pull of the coil in the driving part of the clutch, and hence the resulting mag- netic force seeking to make both parts of the shaft rotate together is lessened. When the generator’s elec- trical load exceeds a certain amount, the opposing mag- netic actions of the two coils neutralize each other and there is no longer a driving connection. This, therefore, slows down the generator until its load is normal. Then the coil in the driving part again dominates. lode

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lodern Publishing Company ATER pumped under a boat embedded in the muddy bottom will help to raise her. From a fire-and-salvage tug above the wreck a hose runs down. Through a larger “‘discharge”’ hose refuse mud and water is sucked up. A diver guides the water-hose down to the bottom of the hull embedded in the mud. The strong current of water from the nozzle bores a hole in the muddy bottom. Work- ing from the opposite side of the wreck, another diver Carries a guide-rope to which are attached the hawsers,

55 Drawing by S. W. Ciat which must be passed around the hull to lift the boat. The monitor, or ‘‘water-gun,’”’ which forms part of the usual equipment of the fire-tug, is dismounted, placed upon a platform, and lowered. The method was first used with complete success in raising the blockships at Zeebrugge. These vessels were heavily weighted with concrete and deeply embedded in the mud. Captain Sir F. W. Young, of the British Admiralty, successfully accomplished the work } orth

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Popular Science Monthly Curing the “Bad Eye” Habit Professor Scott’s machine to speed up slow readers NARLY in the year announce- kK ment was made that the educa- tional department of Spring- field, Massachusetts, had decided to increase the reading capacity of the school children; and that Professor Colin A. Scott, head of the Depart- ment of Education at Mount Holyoke -College, would Cirect the work. Strange as it may sound, Professor Scott is accomplishing his purpose with the aid of a machine—a device of cogged wheels and sliding shutters and speed controls that might be called an “eye-jolter.”’ Early tests showed that the reading capacity of both children and adults varies greatly. It was proved that if 22 per cent of all the people in the United States cannot read at all, there are probably not more than 25 per cent who find any comfort in reading even the newspaper. Graduates of high schools were able to read material as difficult as the ordinary news items at the average rate of 310 words a minute. Some read as slowly as 150 words a minute, while others progressed as rapidly as 450 words a minute. Those who read more rapidly, it was found, were usually able to give as good an account of what they read, and of course a longer account, than those who read more slowly. Ultimately Professor Scott found that the rate of compre- hension was a large factor in determining speed reading. Another point made clear by the tests was that certain me- chanical habits are formed by children, and that some of them interfere with both speed and comprehension. Among them was the habit of fully pronounc- ing words mentally while read- ing silently. The rapid reader never does this, although he can not get along without some pronunciation. He telescopes or slurs kis words, a great advantage in silent reading, but a drawback in that it tends to make the individual a slipshod speaker. The next step was the determination that the rapid reader had a great positive advantage, chiefly because impressions passed before his mind quickly and crowded together into one focus, thus unifying within the span of a few seconds the different elements that went to make up a thought. Then Professor Scott gave his atten- tion to the movements of the eyes as they pass over the material read. “The reader,” he says, ‘usually By Raymonde G. Doyle Professor Scott exposes a section of printed line, covers it up, and ex- poses the next section: if the pupil reads slowly, the machine is geared up to a higher rate of speed— literally ‘‘jolting’’ his eyes along The top photograph records the movements of an eye reading a magazine line. The dots and hesitant lines at the left indicate difficulty in starting. The well defined shifts show that the line was read in four sections. The lower photo- graph shows the reading of a newspaper line (half the length of the magazine line). After one false move, the eye traveled over the line in six jumps, taking about twelve letters at a jump assumes that his eyes glide evenly over the line unless he should be stopped by something not properly seen or under- stood. Accurate observation, how- ever, shows that this is not the case. ‘‘A good reader takes in twelve or thirteen letters in one glance. In order to do this, the eyes rest for a fraction of a second, usually about one third of a second. They then move rapidly to the next section, and so on. “These sections doubtless overlap somewhat on the edges and are of slightly irregular lengths. The eyes move a certain distance and then stop, whether the distance moved is exactly the same as on the previous section or not. The line of travel is along the 56 upper portion of the line, but the center of the resting-point may be, not a letter or a word, but a blank space This makes no difference to the vision, since it is a certain section that is seen, not successively, but at once. In an ordinary newspaper line, a_ rapid reader will make only three stops, and will thus be reading about 350 words a minute. A slow reader, on the other hand, makes as many as seven or more stops and reads perhaps only 160 words a minute.” As a result of his highly important observations, Professor Scott has drawn the conclusion that about half of the slow readers continue to be slow even when the material read could be comprehended by them much more rapidly. Not lack of comprehension, but the persistence of a “bad-eye habit,’’ prevents their reading rapidly. At this stage of his work Professor Scott began to see a glimmer of hope. He invented a machine to correct the “‘bad-eye habit’’ of slow readers. Professor Scott’s machine ex- poses a section of printed line as it would be seen by a good reader, covers it up, and exposes the next section at whatever rate may be found comfortable for the pupil. If, however, the pupil reads slowly, the machine can be geared up gradually, almost imperceptibly, to a higher rate. The machine has proved that the shutting off of an exposed section of a line, the exposure of the next section, and so on, does not interfere with the creation in the reader’s mind of an im- pression of what he has seen. The impressions “overlap,” and the full import of the text is grasped easily. Now, if the reader had been left to struggle along in his own way under the handicaps of a mechani- cal defect in eye movement, what would have happened? Undoubtedly he would have hesitated and lingered on this one line, and divided it into four or five or possibly six sections. But the abrupt shutting off of the first section of the line compelled him to shift his eyes to the next. Literally, his eyes were ‘jolted’? along when his own inclination was to go slowly. Gradually the eyes become ac- customed to being forced to jump ahead, and they jump of themselves. The reader becomes oblivious to the motion of the shutter, and at the end of six weeks is able to read without it at about the same rate as with it. Popnular Science Monthly OQ petw tone vatel large tide | Th ther the v cient twen anch This cente In there of th tides Th suffic powe The The 1 at le: A chan provi large throu loop traf end ( be p mani side dam heigl

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May, 1921 Will the Tides Light London? By P. J. Risdon N the Severn river, England, at () high spring tides the difference between high and low water amounts to nearly fifty feet. At ordinary high water the river can accommodate the largest ocean-going vessels; at low tide such vessels cannot navigate. The suggestion has been made that the river should be dammed to retain the water at a minimum depth suffi- cient to form a locked basin of twenty-seven square miles, affording anchorage for fleets of steamers. This would result in a new shipping center; a new port would develop. In conjunction with this scheme, there is a proposal to utilize a portion of the immense potential power of the tides. The water available is declared sufficient to generate 500,000 horse- power ten hours out of twenty-four. The estimated cost is $150,000,000. The tidal power derived would return at least 5 per cent. on the outlay. A viaduct is to cross the main channel, and in this viaduct a lock is provided, capable of passing the largest vessels. As the locking through of ships would delay traffic, a loop viaduct is provided, so that traffic could be diverted. At each end of the lock a lifting bridge would be provided. The ships would be manipulated by electricity. Oneach side of the channel below the lock a dam would be constructed to the height of high spring tides. In the portions of the dams lead- i : a bs Drawing by G. Bron we 1 ‘ 1 t j 6 Aours /ater y , | j Turbine workin n i || with mmgunted few “ r s e . es Ses is Ss ; n : B Ea p High Tide ee — Gus S. 3 oo a le | At the left is illustrated the action of Severn’s tides on aturbine: There is enough water to gen- erate 500,000 hp. a day viaduct ing to the lock would be placed water turbines. The turbines would be operated by varying water pressures, as work would begin with a head of only a few feet, increasing to thirty feet at low water. The turbines would operate electric generators. In the section marked B in the diagram above, enormous automatic water-tight gates would be _ pro- vided, capable of opening upstream only. Suppose a tide to have reached the level of the water above the dam; the pressure thereafter would be greater outside the dam, and would force the gates open, allowing the tidal water to flow up- stream and raise the water level in the basin to high-tide level. With ebb tide the pressure would be re- versed, and the gates would auto- matically close and retain the water. In the neighborhood of Tintern 57 A. Concrete dams B. Automatic gates operated by the tide C. Highway and railroad Ship lock Shipping wharves Lake ten miles away Future development areas : D. water- | F G (ten miles away) is a lake to which it is proposed to bore a tunnel, forty feet in diameter, through solid rock. The object is to enable the generating plant, in a power house on the banks of the river Wye (when the power demand is less than the power gener- ated), to pump water to the lake, whence it would flow to turbines in the power house and be used for gene- rating electric current during high tide, when the other plant would be idle. As the electricity generated would be far in excess of local demands for many years, it is to be converted to high-voltage current and transmitted to industrial areas. [It is within the bounds of possi- bility that a man in London may glance at the electric lamps in his house, and reflect that they are con- suming current indirectly generated by the moon in mid-ocean.

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Popular Science Monthly Egyptian Mummies Made in America This mummy hasn’t many teeth, but he has horns that will give many a tourist the night- mare. The Egypt- ologist, however, is not impressed by the horns The more hideous the mummy, the better tourists like it. Hence the American manu- facturer is well pleased with the plaster mummy head he is holding in his hand. By careful painting he is able to give his mummies the proper long-dead hue With his shirt sleeves rolled up and a straw hat on his head, this unromantic business man wraps linen around the emaciated legs of the “mummy” he made They haven’t enough mum- mies in Egypt to satisfy the curiosity of tourists. Hence this plaster-mummy maker is given plenty of work to do. When he finishes one, he ships it in a box on which is written, ‘‘Handle with care” It may happen that an American sometimes travels many hundreds of miles to be thrilled and horrified by mum- mies manufactured in his home town “Flying Express” 8 a s Seoernn NOVEL aerial railway, or flying express, has been devised by Francis Laur, of Paris, France. Its structure perhaps more nearly approximates that of a suspension bridge than any other structure with which it might be compared. on its course. 58 From the elevated rails there depends a cigar- shaped aerial railway-car, which at its forward end carries a substantial airplane propeller of the puller type, by means of which the car is propelled The structure is entirely of metal. nav pur imp A bas lan mus fast 71 wit. mor La y: ing La side dist hav ma: bee tor: to rise ele’ pla I ma hoi pla har gul five Th cor ] oth ars not als d an —yy9r

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May, 1921 : HE aircraft carrier is one of the : most important developments of 4 naval war. With aircraft for spotting a purposes a battleship’s gunnery was a improved 30 to 40 per cent. An aircraft carrier must be repair base, fuel base, and launching and landing platform for airplanes. She must have speed, for the fleet is only as fast. as its slowest ship. The former collier Jupiter, equipped with the electric drive, has been re- modeled to carry planes, and renamed Langley. A large deck is required as a launch- ing and landing platform. So the Langley ejects her smoke through the sides by tubes that carry it aft before discharging it. All modern ships must have masts for radio equipment, and masts that telescope into the ship have been fitted to the Langley. The eleva- tors that take the airplanes to and from the platform rise so that the floor of the elevators is flush with the platform. Below the platform is the main deck on which are hoists to lift seaplanes and place them in repair-shop or hangar. This is also the gun-deck upon which four five-inch guns are mounted. The quarters for the ship’s complement are located here. Below this deck lies an- other on which are the hang- ars, Where all the seaplanes not under repair are carried, also the repair-shop. A crew of twelve officers and a hundred and seventy- Mother to the Seaplanes By Graser Schornstheimer nine enlisted men will be carried in addition to the aviation comple- ment. The Langley will probably carry thirty airplanes. Both land and sea types will be used, divided into these classes: fighting planes, scout- ing planes, scouting and spotting planes, torpedo planes, and possibly some bombing planes. The Langley is probably too slow for the duties she is expected to per- form. All battleships have a speed of twenty-one knots; the Langley has but fifteen. The position of the aircraft carrier with the fleet is in the smoke screen. Then it can help ward off destroyer and submarine attacks and make the scouting planes more efficient. For this service a ship needs every knot of speed that can be given her. —_ —— — y a To be an aircraft carrier a ship must have a large, clear deck, and she must have speed enough to keep up with the fleet He is receiving radio messages with a small apparatus that looks like a book It Isn’t a Book, But a Radio Outfit I ERE is a radio outfit ar- ranged in a flat box. The man puts up a small aerial, on a cane, takes out his ‘‘book,”’ adjusts his receivers over his head, and combs radio mes- sages from the sky. He “tunes” his outfit to different wave-lengths by adjusting the covers of the book. When the book is wide open, the radio equipment is ready to receive from stations with long wave-lengths. When the book is closed, the outfit is tuned to receive messages from small amateur stations. Signals have been received over a distance of 300 miles. to Carry Passengers and Mail between Lille and Turcoing uaib eset |: as investigation. This novel system of locomotion has been approved by the Commission Interministérielle, which was nominated by the French government to make an Construction has already begun on a line running between Lille, Roubaix and Tourcoing. rapid transportation. tion? 59 The line is designed for the transportation of passengers and mails, being constructed to provide But why all this complica- Why not an airplane or airship service be- tween the points bridged by this elaborate structure?

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Popular Science Monthly Microscope and Telescope Too With one instrument you can either see the mountains on the moon or magnify a spider to the size of a cat UPPOSE that there were an instrument that is both a telescope and a microscope. Suppose that at a distance of twenty-nine feet you could with its aid read small print in a dictionary, or see the individual hairs on a mouse twelve feet away, or identify plants on a wall a quarter of a mile off. All this the wonderful Davon micro- telescope does. To understand just how it accommodates itself miracu- lously to distance, you must understand the principle on which both the tele- scope and the microscope are con- structed. In order to realize the advantages of the micro-telescope we have to con- sider the limits of ordinary telescopes. Disregarding, as we may, complica- tions and refinements, a telescope con- sists essentially of an object-glass at one end and at the other end an eye- piece that is but a microscope. The object-glass focuses the image of an object upon the microscope lens by which it is magnified. The propor- tioning of the parts limits the range of an ordinary telescope. A_ telescope designed for observing the outer planets would not be suitable for studying insect life at ten yards range. The Davon Micro -Telescope A microscope consists of one or more magnifying lenses, called the ob- jectives, which magnify and project its enlarged image upon the eye-piece of the instrument. Every one who has used a powerful microscope is aware that an object can be examined under it only in a given plane. Consequently, specimens for examination have to be specially prepared. For instance, for the microscopic examination of metals, sections of the metal with perfectly flat surfaces By P. J. Risdon English Correspondent of the Popular Science Monthly garden wall and you see a spider a few yards off magnified to the size of a large cat. To do these things, simply turn a screw. Owing to the depth of focus of the micro-telescope, that is, its equal mag- nification, at the same time, of the different portions of an object, a fractured section of steel, or mineral, any object, in fact, is simply placed in position and examined with a mag- nification of from thirty to ninety diameter, at a distance of from one to three feet from the object. The depths of the cavities are brought into view, as well as the protuberances. The instrument consists of an or- dinary microscope to which is fitted an extension piece that is virtually the telescope, except that the microscope itself constitutes the eye-piece. There are two different extensions, known as the long- and the short-focus attach- ments. The long-focus attachment enzbies the instrument to be used for objects at any distance exceedi’.z six feet, to infinity. Thus eithci the moon cr an object on the other side of the room may be examine’, tne mag- nification being variable up to sixty diameters. The short-focus attach- ment is for microscopic observation at distances of from one to three feet. Each attachment consists of a tube fitted with an object-glass and a series of ‘‘stops’”’ or hcled diaphragms that have the effect of sharpening the im- age. Any standard microscope can be converted into a micro-telescope by fitting either attachment into the rim. With the short attachment you can examine microscopically anything that, because of its size or shape, could not be examined either with a microscope or a telescope. For mere examination of objects both near and far a self-contained instrument may be obtained resem- bling a small pocket telescope thirteen inches long. For indoor work this may be mounted on an ordinary stand; for field work it may be held like a telescope or mounted on a tripod, or screwed to a tree or post by means of a gimlet attachment. When used on an ordinary stand, a flat mirror clipped to the end of the telescope enables high angle views—for instance, the moon overhead. A Camera Is Part of the Equipment Whatever can be seen through the micro-telescope can be photographed. A camera forms part of the equipment, The eye-piece of the microscope and its tube are removed, so that the mag- nified image of the object is focused directly on to the ground glass. The super-microscope (as distinct from the micro-telescope, in which the microscope magnifies an ‘‘air’’ image of a more or less distant object, which is formed on the plane of the microscope stage by means of the telescope lens employed) deals with an image formed in the air, of a near object such as a microscopic specimen. This ‘‘real’’ image is obtained through a micro- scope objective that takes the place of the telescope objective. The result of magnifying by a microscope the image formed by another is remarkable. The distance between the object and the objective is increased. Considerably great depth of focus is acquired, and not at the expense of the definition. Further, about twice the magnifica- tion that any given microscope object- ive is supposed to stand is obtained by means of the have to be prepared and etched with acid. Other ob- jects are prepared by flatten- ing them out, or alternatively the focus of the microscope has to be frequently altered, to enable the different parts of the surface to be examined successively. Now comes the Davon micro-telescope, a combina- tion of a microscope and tele- scope. Range and depth of focus are obtained at one and the same time, which is abso- lutely impossible with either instrument alone. Turn it on super-microscope. By substi- tuting a camera for the eye- piece tube and eye-piece of the microscope, photo-micrography is simplified. Photographs of metal fractures at life size, metallography up to fifteen hundred diameters, and photo- micrography to three thousand diameters has been taken in this way with most excellent results. In the fields of science and commerce the micro-tele- scope and _ super-microscope should prove invaluable to metallurgists, mineralogists. geologists, botanists, engineers, the moon and you will see its mountains. Turn it on the A photograph of a diatom taken with the super- microscope; it is magnified three thousand diameters 60 surveyors, doctors, and to the intelligent public generally. May, — an Se

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—_— mm (> ctr Pen dD wR + May, 1921 MICRO -TELESCOPE FOR BENCH WORK Shading Phoograph of House taken at%4 mile adistence with ordinary Camera. erver usifig vice Type Fy eye , ON ee ISTO LEICSCOPESG th athachment for Freing to a tree. Miia Carriage Rail Oak bench Operator photographing disfan? mountains with the Micro-Jelescope Super Camera. haus! Drawing by G. H. Davis. © Modern Publishing Co. The Telescope that In the wonderful new Davon micro-telescope, a telescope is converted into a microscope merely by separating the lenses and applying a microscopic attachment. When a camera is attached to it, photo- micrographs may be taken. Attached to a tree, as Same view faken by witht Micro-Telascops distance’ 3 4 I72) ’ Camere Seer. a Is Also a Microscope shown in the center picture, it can be used as a telescope. As a photo-microscope the instrument photographed the house shown in the detail picture at the right at a distance of three fourths of a mile. photograph taken by an ordinary camera Compare the Photographs courtesy L. Davidson & Co 61

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© Ewing Galloway J Seesawing on Wheels HEN children seesawed ten years ago, they were quite content to sing about Marjorie Daw—and get nowhere. Now, however, they like to travel. And the result? The moving seesaw. It was invented by Carl Gebert, of New York city, and is shown here traveling down Fifth avenue As the boys on the ends swing up and down, the motion is im- parted to gears that are con- nected with the large wheels. Thus, the faster the boys swing, the faster they move. There are wooden crosspieces mounted above the small guiding wheels that the boys use for “‘pushing off.’ Eskimos Now Eat Cooked Fish EEDING fish to Indian and Eskimo children is one of the tasks of the Hay River Mission, located near Great Slave lake, in the northwestern part of Canada. The Indian and Eskimo children in the neighborhood are little savages and like their fish raw. But the missionaries are teaching them to eat it cooked. The picture below shows how the fish are cooked. Poles are driven into the ground, and pieces of cleaned fish are stuck on the ends of the poles. A fire of pinewood is built under the fish. Two in a Side Car HE motorcycle is the poor man’s automobile. It is growing in use and popularity every year. The side car has increased its carrying capacity and added a touch of com- fort for those who would like to ride without straddling the machine on a rear seat. The side car, however, has always been a one-person outfit. Here is a side car built for two. There is plenty of room for the passengers to ride in comfort. The spring suspen- sion gives the machine the riding qualities of a small automobile. It is not improbable that this side car will threaten the taxi’s great popularity. American Eyeglasses in Mukden URING the past few years—especially since the opening of government schools in 1907—there has been a large demand in Mukden for eyeglasses. The students, who form no small part of the residents in the larger cities, have taken chiefly to wearing spectacles. The violent wind-storms of the country also make goggles welcome as a protection from the dust. Most of the eyeglasses found in the Japanese shops are of American manu- facture, which the natives seem to prefer rather than the small-lensed product that is manufactured by the Japanese. Popular Science Monthly Driven by an Airplane Propeller ORE than twenty years ago Count von Zeppelin buil his first giant dirigible airshi To determine whether the pr: peller that had been designed would drive his airship at a cer- tain speed, he mounted the pr: peller on a launch. The pro- peller churned, not water, but air, just as on a dirigible. A queer vehicle recently mad: its appearance on the streets oi Los Angeles. An automobil engine drives a large air pro- peller, which is enclosed in a kind of cage. The air-screw, by “boring” into the air, pushes th machine along, thus indirect}: utilizing its power. ‘6400 Miles to the North Pole’”’ ie books on polar exploration, authors are sure to tell you that “‘we erected a cairn to mark our position.” The cairn is a kind of signpost, built of stones or wood from the sleds. Ali these signposts are of interest, but this one especially, because it was built by the late Admiral Peary on that trip when he actually reached the Pole, after a struggle of twenty-three years. Captain Godford Hansen, leader of a Danish expe- dition, stumbled on Peary’s cairn, and no doubt found it useful. To him it meant ‘400 miles to the North Pole.” May, _ "4 ¢ 4 : : Loe W NQU Sta decide or ‘‘sti Tw betwee were t. and a five tl tically mined lateral blocks spring Vari the st differe rollers ing-bl« the arr Plz De a leather days o on the encase are no flated. The mobile of cor adapta is exer is used In t tangle of the momer danger footbal victims bump « of any

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May, 1921 What Is ‘‘Still’’ Friction? NQUISITIVE men of the Bureau of Standards, Washington, D. C., recently decided to make a few tests on the static or ‘‘still’’ friction of ball bearings. Two large ball bearings were placed between two steel blocks. The blocks were then placed under a testing-machine, and a pressure of from five hundred to five thousand pounds was applied ver- tically. The friction present was deter- mined by the force required to produce a lateral motion of the ball between the blocks as measured by means of a tubular spring balance. Various forms of raceways were cut in the steel blocks, and ball bearings of different sizes were employed. Two rollers were placed under the lower test- ing-block to add stability and to prevent the arrangement from falling out. Playing Football on Bicycles ICTIONARIES say that a football is a large india-rubber ball encased in leather. Such were the footballs of earlier days of the game. To-day they are built on the plan of automobile tires, and, while encased in the same tough material, they are not solid ecres of rubber, but are in- flated. The great pressure exerted on an auto- mobile tire shows how strong is a cushion of compressed air. Here, in the new adaptation of football, no such pressure is exerted. The front wheel of the bicycle is used to send the ball toward its goal. In this game, one can imagine what a tangle of wheels must occur when a number of the riders rush together at an exciting moment, although it is doubtful if it is as dangerous as either Association or Rugby football, which each have a long list of victims to their credit. But what is a bump or a sprain to a good outdoor game of any kind? { © Keystone View Company ‘‘Entrance for All Soles’’ O reads the sign that appears over the doorway of a New York store. You wonder at first whether the owner really means ‘“‘soles’”’ or “‘souls,’’ and then you notice that the doorway itself is cut in the shape of a sole. The store is one in which shoe-repairing and shining are done. And the sole-shaped entrance is cut out of white cardboard. It is very noticeable and has attracted many people to the store—which was exactly what the owner wanted. The canny storekeeper made other plays on the word ‘“‘sole,’’ as you see. Saving Helium for the Future CCORDING to Richard B. Moore, 4 chief chemist of the United States Bureau of Mines, the United States is richer in helium than any other country. She is taking steps to conserve the supply, having built two plants, one for experi- mentation and the other for extracting helium from the natural gas. Helium is valuable in filling balloons and dirigibles. It is non-inflammable, and therefore safer than hydrogen. It Holds the Telephone-Book si HERE’S the telephone-book?” Most of us have asked that ques- tion many times. Telephone-books should have a fixed place in the world— especially in the world of business. In the picture above you see a new holder that can be fastened to the side of your desk. It keeps the book entirely out of the way when it is not in use. Yet, when you wish to look up a number, all you have to do is swing the holder to your side and raise the curved handle at the bottom. The book will automatically open as you raise it to a horizontal posi- tion. On releasing the handle, the holder will lock itself in that position and remain there until you have found your number Then you press a small button near the handle. Is He Dead or Alive? HE Nubian crocodile, like his com- panion of the jungle, the lion, is reputed to be the most vicious of his species. The captive shown in the picture below is a fine specimen of those that frequent the Ganges river in India, where they were considered sacred and were treated with respect and awe, even to the extent of the natives flinging their babies to them as a fitting sacrifice to the river god. Millions of years ago crocodiles were undoubtedly native also to England and France; their remains have been found in fresh-water deposits and near the mouths of supposed rivers. This specimen is dead, though he is to all appearances very much alive. The photograph was made by James Ricalton, of Maplewood, New Jersey, who has spent many years in the wilds of Africa.

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Popular Science Monthly

Mount the Flashlamp in a Holder HE handy little flashlamp becomes handier when it doesn’t have to be held in the fingers. To train the light on a certain spot, yet have both hands free, is an accomplish- ment afforded by the metal clamp recently invented by William Waegel, of Reading, Pennsylvania. The holder can be attached to almost anything, or it can be laid on the ground and the light turned in any direction. Not only can a flashlamp be used in the holder, but it can be used to hold an ordinary electric lamp. The holder consists of a metal clamp carrying a pivoting device. $30,000,000 in a Chair N the Shah’s palace at Teheran may be seen the celebrated Peacock Throne, shown in our photograph, and valued at more than $30,000,000. It was taken from the Grand Mogul at Delhi by the victori- ous Nadir Shah. It is in many ways a curious and wonder- ful article, virtually a single chair, upon which the Shah sits when he holds diplo- matic receptions. The wood is of the finest ebony, and most elaborately carved, and ornamented with sheets of gold on which are enamels, fantastic birds, and chimeras set with precious stones, culmi- nating in a diamond sun.

How Mount Vesuvius Looks through a Telescope AN active volcano, such as Mount + Vesuvius, is one of the most interest- ing spectacles afforded to the eyes of man. Like any dangerous cataclysm, its bursts of flame and explosions of “lava bombs”’ are safer to witness from a distance than near by. Here the telescopic camera comes in with advantage. The photograph shown above was taken in September, 1920, through a camera equipped with a telescopic lens. The opening in the side of the crater, through which the smoke and poisonous gases issued, is more than a mile and one half in diameter. An observatory on a near-by ridge, supported as a national in- stitution, has taken a continuous record of each phase in the eruptions of .Vesuvius for many years. When the wind is favorable, it is sur- prising how close one can approach the dangerous field of Vesuvius. But with a telescope one does not have to await the change of direction of the wind. © Keystone View Compaay

Courtesy of “‘Western Electric News” Saturday Night in Japan a Serious Matter E have been told thai the United States ha: more bath-tubs to the squar mile than any other country but even some of us can re member the Saturday-nigh bath in the kitchen. Crudea it was, the old kitchen was comfortabl in the warm glow of the fire. Contrast with this the discomfort oi taking a bath in Japan, as shown by th: picture. Note the small stove and th: drainpipe flue that releases the smoke just on a level with the washed one’s head. The tub itself looks leaky, and the rough edgy makes one shudder. Taking a Vapor Bath OR administering vapor baths in con- junction with electric-light baths, and for controlling the apparatus at will, Winfred S. Clum, of Wilkinson, Indiana, has devised a cabinet equipped for either gas, alcohol, or electric heat. The boiling system consists of a supply tank that holds a gallon of water, which is automatically supplied to a boiling-pan. The heating element is located within the heat-chamber. It is easily controlled. The apparatus is used for the treatment of rheumatism, neuritis, neuralgia, obesity, blood-pressure, and various lung and bronchial affections.

_ BOILING~ SRIPANS

ELECTRIC TL SoPA CI

May

Lal M parts is an Prod Gl proot virtu cleav of ch new | only Dr meat an | nous are n easily TI G 4 Ti grap turn being TI mecl Tray the r shuff labor there If days use ( the | ture for <

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May, 1921 || Glue Made of Blood NV ANUFACTURING a new glue from 4 blood for use in welding airplane parts and in plywood exposed to moisture is an achievement credited to the Forest Products Laboratory. Glue made from blood is more water- proof than the casein glues now in use, a virtue that is especially desirable in the cleavage of woods exposed to the dampness of changing atmospheric conditions. The new glue will hold together layers of wood only 1/125 in. thick. Dried blood albumin is received from the meat-packing establishments. Fresh blood can be employed only when the slaughter- houses and glue-manufacturing facilities are not far removed; for blood coagulates easily and decomposes. This Egg-Turner Is of Simple Construction ~GGS for hatching are always collected 4 in cold weather to avoid freezing. The poultryman shown in this photo- graph has built a homemade device for turning the eggs when large numbers are being saved for hatching. The illustration clearly shows’ the mechanical details of the turning-rack. Trays expose the eggs to the warmth of the room; otherwise the eggs would require shuffling with the hands. The rack is a labor-saving device for handling eggs where there is a temperature of from 50° to 60° F. If the collection is stored for only a few days, a turnover is unnecessary. Daily use of the turning -rack is recommended by the United States Department of Agricul- ture if the eggs are to be retained in storage for a week. Ordinarily, commercial egg- cases will answer the purposes of a turning device. © International Film Service Practising Golf-Strokes in Front of a Mirror HE ambitious beginner in golf ner- vously takes his stand, and swings at the ball with the grace of an old-timer. After the dust clears away, he finds the ball un- disturbed at his feet. The onlookers enjoy the show, while Mr. Beginner feels like crawling into the sand- box. A lot of embarrassment may be saved by learning to hit the ball indoors before any attempt is made on the links. By practising in front of a mirror, the beginner can train himself to really hit the ball. When he does hit the ball, a big net catches it. aa) Carriers that Preserve Fruit ANANAS become. discolored when bruised and the discoloration spreads; hence the banana becomes uneatable. Frank Schmitz has invented a banana carrier that guards the fruit from harm. It consists of a burlap sack that is fastened to the inside of a cylindrically shaped crate. The inventor tells us that this carrier can be used for at least a hundred trips. The crate is made of elm strips held together by heavy hoops. The sack is sewed to the crate with twine at each inter- section of each hoop andstrip. The mouth of the bag is located well within the outside hoop. Thus the bananas inside the bag do not come into contact with any solid sub- stance that might bruise them. 65 , eliminating the § There are air holes in the padded palm to More Space in the Theater GREAT and noble act for suffering humanity was achieved by the man who invented this theater seat. Did you ever sit on the end seat in a ‘‘movie”’ theater and manage to see all of the pic- ture? If you did, you had a wonderful piece of luck. Usually, just as the villain is choking the poor, defenceless girl, in comes a lady with five children to file past you. The kids walk all over your new shine and then you try hard to smile cheerfully when the lady begs your pardon. This new seat has an opening cut in one side. When people pass, it is only necessary to turn and place your legs in the opening. This leaves plenty of space for people to pass you. The Ball Can’t Drop Out of This Glove “H E’S muffed it!’ The crowd groans as the second-baseman fails to hold the fast ball that shot his way. The speed at which the ball travels creates a cushion of compressed air in front of it. Thus, as it reaches his glove, the compressed air causes the ball to rebound. Major Robert H. Young, of the United States Air Service, has invented a baseball glove that swallows this compressed air, creating a partial vacuum in the glove and tendency to rebound. which flexible tubes are attached. These tubes have their outlets in the sides of the glove. There are valves at the ends of the tubes that prevent air from entering.

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Popular Science Monthly This Is an Electric For Setting Off Hair-Clipper OUR hundred and thirty clips a minute that is the speed of this hair-clipper. The man who dislikes the ‘‘feel’” of hand clippers sneaking up the back of his neck will certainly be interested in the sensation this machine will produce It gives him a combination massage (because of the rapid vibration) and hair-cut. A small electric motor attached to the handle of the clipper drives it A worm reduction gear is used The entire outfit weighs slightly more than a pound, so it behooves the operator ta make haste. Carrying a Dairy Aboard Ship HE owner of a Swedish freighter de- cided to take a trip on his vessel. He wanted to take his children also, and the question of milk had to be considered. The children had to be supplied with fresh milk every day, so their father decided to take two cows A cowshed was built on the upper deck, and two good Swedish milch-cows were placed in it. They crossed the ocean with- out suffering, and gave their full quota of milk each day. The picture below shows that the cows had found their sea-legs and were at home on a sloping deck. Fish Taken Alive to Canneries NCE herring are caught, they must be transported tothe cannery. If the net in which they were caught were towed to the cannery, many fish would be dead be- fore they reached their destination. If they are taken from the water and placed aboard, then it is necessary to handle them twice. When this newly developed barge is brought into use, a great mass of fish may be transported to the cannery with ease. The stern of the barge is open. The sides and the bottom are covered with.a heavy net. The net in which the fish are caught is dumped into the barge. The barge is then towed to the cannery. America’s Wealth in Poultry Ar you eating more than half an egg a day? If so, you are getting more than your share of the product of the nation’s poultry-yard. According to a recent estimate, there are in the United States 599,000,000 fowls. These produce annually 1,921,- 000,000 dozen eggs, worth $1,179,000,000. The average value of eggs is one third that of corn, and half that of wheat, and the same as cotton. the Dynamite LASTING machines have always been very heavy. Here is a small light one, weighing only thr2e and one quarter pounds. It is so small that it may be placed in the pocket and carried from place to place When the handle is given a sharp turn, a momentary current of great strength is generated. This is sufficient to set off five or six charges of dynamite when they are connected in series. The little blaster is just the thing for the farmer. It saves the trouble of a fuse. Shock-Absorbers for Piers HEN a 10,000-ton vessel ‘‘leans”’ against a pier, strains are set up in the pier and the vessel. The strains in the pier often result in damage. An engineer of a shipping company in Los Angeles developed a pier shock- absorber. A strip made of several large timbers is placed along the edge of the pier. This is separated from the pier by heavy springs similar to those used on the trucks of freight-cars. When a vessel bumps into this, all the strain is taken up by the springs, and damage to the pier is in this manner prevented. May; I Co ; | j \ hy S i be TOI fo! ones. small It is ¢ in the It quen! hund MOVE Infa tank Tok the g tne € syste Tg gallo back

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we eS re ere rH May, 1921 Smaller and Cheaper 7OU can get plenty of second-hand cars for four hundred dollars—but not new ones. However, there is now a car, a very small one, that costs even less than that. It is a three-wheeler, the single wheel being in the rear. It is very simply made and is conse- quently very light, weighing about one hundred and fifty pounds. The gears that move it are fully exposed to the public eye. Infact, so is the engine and the gasoline tank. Why, then, is there a hood in front? To keep up appearances, undoubtedly. As the gasoline feeds directly from the tank to the engine, there is no need for a vacuum system that might easily get out of order. The tank is a small one—holds about a gallon of gasoline—and is attached to the back of the driver’s seat. Save Your Safety-Razor Blades NCE again that cast-off safety-razor blade fills a long-felt want. This time it goes into the making of a handy cigar- cutter—handy because it will fit a man’s vest pocket. The construction of this cigar-cutter is very simple. Two pieces of papier-mdché cover the blade, which is held in place by an eyelet. In the center is the hole that accommodates the tip of the cigar. There is a safety catch at one end of the cutter. © Keystone View Company Hooking the Motor-Car Speeder CALIFORNIA speed cop is constantly on the lookout for motorists who are exceeding the speed limit or otherwise transgressing the rules of the road. When he spies a driver who is not pursu- ing the even tenor of his way, he gives chase on his motorcycle. If the car-operator re- fuses to stop on command, the officer speeds up—sometimes sprinting at a fifty- mile-an-hour gait—until he comes along- side the fleeing motor-car. He hooks one end of a short tie-rope to the automobile, the other end of the rope being secured to the handle-bars of the motorcycle. The rope is just long enough to hold the bicycle against the running-board so that it coasts along and permits the oflicer—if necessary—to step from his seat to the running-board. Why Not Take Your Music Comfortably ? Lightning Punctures a Pavement HIRTY-FIVE thousand volts will en- able a current of electricity to jump across an air-gap of one inch. The average bolt of lightning, which is purely an electrical discharge, is about one mile and a half long. How many volts does it represent? Several tril- lion volts is about as close an estimate as can be made. This terrific discharge has a powerful rupturing force. Evidence of this is shown in the photograph. The stroke of lightning bored a hole in the pavement about one half inch in diameter and continued on its way. A high héat is generated at the instant of impact that may reach several thousand degrees, and it is well not to be standing near. other. able. twenty-five records. records without getting up. IVANS of today are enormous pieces of furni- ture with very wide arm-rests at the ends. Why not put these arm-rests to use? A Western manufacturer suggests phonograph in one and a case for records in the Neither phonograph nor record-case can be seen unless the tops of the arm-rests are raised, as shown in the picture below. The sound-box of the phonograph has its opening in the front, but it is covered so that it is not notice- The record-case will hold one hundred and Thus you can play that many Pa Y Bil meas ce ee un WFe Te eu tibu fe bb Ban Bu hed bu Bee wh building a "bart | bg No Puddle Here HAvE you ever had on a nice clean pair of white shoes and tried to get a drink of water from a public fountain located in the center of a big puddle? Well, here is a little idea that will avoid the formation of a puddle by taking care of the over- flow. This very simple de- vice has saved a certain municipality the expense of installing an expensive drainage system, also the inconvenience of ditches in the city streets. A large piece of tile pipe : is placed around the foun- Hh tain and the space between — is filled with sand. The water flows into the sand and seeps away into the ground.

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A clever idea! Walter R. Rousar, a reader of Popular Science residing in Schuyler, Nebraska, has placed a drawer in the staircase. In this, his wife places all the linen used down- stairs. A good step-saver Mrs. George L. Paustian, of Davenport, Iowa, has arranged a faucet near her gas-stove to save her the labor and the steps necessary to carry the heavy wash-boiler from the sink across to the stove Not necessarily a step-saver, but a labor-saver—the vacuum cleaner quickly drys the kitchen floor. The second prize of twenty-five dollars was awarded George Benders, of Jersey City, New Jersey, for this WATER-PIPE Wheels on the kitchen table enable the housewife to move the table to her work instead of taking her work to the table. Winfield M. Bayer, of Hartford, Connecticut, is responsible for this simple, common-sense idea re anaeet Ny at tit al a so ee ALS VALVE FROM" 4 yy * i C. S. Caldwell, of |[Birmingham, Alabama, finds this idea saves him many a weary step when he is doing the garden chores 68 Popular Science Monthly Some Ways to Save H. C. Rowell, winner of the first prize in the Popular Science Monthly’s Step- Saving Home Contest, con- structed a hydraulic lift to bring coal from the cellar. G. Benders, winner of the This idea will save steps and labor. The coal-hod and the wood-box are placed on casters. The hod may be rolled eliminating much lifting VAWES I HANDLER | FstOn ea ee Hi us’ Here is the idea that won the first prize of fifty dollars. H. C. Rowell, of Hudson, New Hampshire, suggests in- stalling a simple hydraulic lift to carry fuel from the cellar. The city water sys- tem has plenty of pressure for this use tf) se Va bl at th W) i j _—

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May, 1 921 Steps in the Home second prize, found that the vacuum cleaner will dry the kitchen floor. C. R. Trim- ble, a New York top-floor- apartment dweller, meets the milkman every morning with a hoist A board attached to the gas-stove ac- commodates the kitchen utensils where they are needed. E.G. Eggensperger, of St. Paul, Minnesota, entered this idea A single telephone for both floors. This is the idea of George Lee, of Chicago. It saves steps and time. Any good home mechanic can install the device in a few hours and by this means save many steps for every member of the household Miss Edna Purdy, of Chicago, has found this to be a real step- saver. She has brought an old bicycle wheel into use as a pan- Do you know what is in your and kettle-holder. By simply attic? Keep a list of the things revolving the wheel she can take down any kettle or other utensil without moving you put away. Consult it when you are searching for some article that promises to be useful — It looks simple, but it does the trick. The sponge absorbs the water from a leaky valve. The water evaporates from the C. R. Trimble, of New York city, won the third prize with this idea, which will be appre- ciated by people living above sponge and helps to keep the the first floor in apartment room at the proper degree of houses. He meets the milkman humidity every morning with this hoist Niu? / ae sy) = i : ’ WATER-TIGHT FILLING DOORS Hy asnes-REMOVAL Se poor ASHES | (THROWN OUT) S. Senam, of Calgary, Alberta, Canada, built an outside coalbin that serves the furnace and the stove and takes the steps out of delivering coal 69

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— This device will measure a taper in less time than it takes to tell. Tapers are difficult to measure with ordinary tools, but both speed and accuracy will be acquired with the use of this measure not in use. Wood absorbs moisture, and moisture causes wood to warp. This warping is espe- cially damaging to wooden patterns. Now aluminum leaf—aluminum beaten out into very thin sheets—is used to cover the expensive wooden patterns. It prevents the absorption of moisture busy feeding it. on a swivel, Here is a rough boring and milling machine of new design. The boring spindles are mounted directly opposite the milling cutters, The revolving table is driven by compressed air This crane travels on a track that can be raised when It can be used in an inclined position to lift cargo off vessels Four fuses in one. When the fuse “blows.” it is simply turned one quarter way around and an- other fuse is brought into place 70 A horizontal disk-grinder that will keep one man It has four vises, which revolve While one casting is being ground, the operator is attaching another In big rolling-mills, taking the freshly drawn wire from the spools has always been a problem. Now comes the -spool that shrinks in diameter so that the wire may be lifted off without trouble Popular Science Monthly and Machines Discovering torn sprocket- holes in motion-picture film. This machine is also used to discover films that are out of register on the screen. With this device one person can inspect many thousand feet of film in a day, thereby making it a valuable access- ory to motion-picture studios A portable boring-bar that bores cylinders on the job. It is at work here boring out a steam-engine cylinder. It is attached to the cylinder with clamps a - Ma 5 A part like and peel V of a sod ultr whe dry Yet wat 71 ing cou has mo lize pre be

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=—sS oT asked AN A Pied Se ny eee tlle cit. May, 1921 Keeping Up with the March of Science Facts for the man who wants to know Semsathine Mew in Scil NEW soil substance has been dis- 4 covered by the United States De- partment of Agriculture. It is a gelatin- like material that is very plastic when wet and resembles resin when dried. It has been named “‘ultra-clay.”’ When analyzed, it appears to be a silicate of alumina combined with iron, potassium, sodium, magnesium, and calcium. The ultra-clay has been added to loose sand when moist, and made into briquettes; on drying, it has become tremendously strong. Yet, when the briquettes have been put in water, they have fallen to pieces. The Department of Agriculture is mak- ing a detailed survey of soil all over the country. At present one third of the land has been investigated. However, since mountain and desert land will not be uti- lized for agricultural purposes at the present time, this part of the work can be eliminated. Eat and Grow Hair “TAT and grow thin” is a slogan that may soon be supplanted by “Eat and grow hair.’’ Internal application, it has been found, will:-make sheep’s wool grow quicker, longer, and stronger. If keratin— a substance in the body that forms the chemical basis for hair—is duplicated as far as possible and fed to sheep, their wool will increase. Mr. N. Zuntz, the chemist who has been experimenting with keratin derivatives, tried them on himself, and found that his hair responded. Both the hair on his head and in his beard grew faster and thicker. However, if this sort of thing were carried too far, the keratin-eater might find him- self turning into a gorilla-like creature. Why Not More Parachutes? NE of the officers of the R-34, the his- toric dirigible that crossed and _ re- crossed the Atlantic ocean in 1919, recently made the statement before the Royal Aeronautical Society in London, that dur- ing the war 750 English officers and 800 Frenchmen had saved themselves from burning observation balloons by means of parachutes. Had the war lasted longer, said Commodore Maitland, all aircraft would have been equipped with para- chutes. How does it feel to drop a mile or two through the air from a dirigible, or even from a lesser height when an observation balloon has been shot to pieces? The sen- sation is unpleasant, says Commodore Maitland, but the experience is not danger- ous. Some men prefer to dive head first, and some to drop feet first. The anxious moment comes when landing. The parachutist never knows on what he will alight. Trees prove a safe enough bed in summer, when they are covered with foliage, but they are “horribly spiky” in winter. The sea is positively delightful to land upon—‘‘like jumping on a feather- bed, only nicer,” according to Maitland. How hard do you land? About as hard as when you jump four to five feet. After these revelations there seems to be no very good reason why every flying- machine and _ dirigible should not be equipped with parachutes. Don’t Waste Gas regen gas-bills are sometimes caused by unsuspected waste on the part of the consumer. According to a paper issued by the Bureau of Mines, 80 per cent of the gas received is wasted. How does this happen? In many cook- ing and heating appliances the position of the gas flame is incorrect. In cooking, the point of the flame should touch the pot. If it does not reach that far, heat is wasted; and if it licks the sides of the pot, gas is wasted. Then again, if the mixture of gas and air is incorrect, a yellow flame will result. This contains very little heat and will turn the pot black. A non-luminous blue flame con- tains the greatest amount of heat. Saving Old Red Corpuscles IPHTHERIA serum and many other serums are made from the fluid part of horses’ blood. A healthy animal is bled, about thirty-six quarts being taken from it in a week, and the blood is allowed to stand until the red corpuscles have settled at the bottom. The fluid is then drawn off, and the red corpuscles thrown away. Dr. W. J. Penford, director of the Aus- tralian Commonwealth Serum Institute, considered this a tremendous waste, and he tried injecting the red corpuscles into the horses again. The result? The horses are able to form corresponding fluid rapidly, and a greater amount of blood can be removed from them. Instead of thirty-six quarts, forty-eight quarts can be removed ina week. The composition of the blood is not affected by this forced formation. Rain the World Over HAT happens to rain after it falls? Some sinks into the ground, some evaporates, and some drains off through rivers into the sea, carrying tons of solid matter with it. In actual figures, 29,347 cubic miles of water fall on the earth in a year. And as one cubic mile of water weighs more than four billion tons, the -total weight is enormous. About one fifth of the total rainfall is carried into the ocean, and it takes with it almost three billion tons of solid matter. 71 Leather from Yeast es EN parts of yeast containing fifty per cent water’’—when a recipe calls for yeast, you immediately think of “home brew.”’ But in this case it has to do with synthetic leather and rubber. The yeast is mixed with one part of glycerine and six tenths part of tar. When this is properly mixed, six tenths part of glue is dissolved in it, and the whole is treated with formal- dehyde, heated, and pressed into molds when hot. If rubber is desired a low exerted, whereas if leather high pressure is exerted. pressure results in a soft Para rubber. pressure is is desired a A very slight material like How Worms Taste “ ANIMATED noodles” is the term ap- + plied to one of the favorite dishes of the Mono Lake Indians of southern Cali- fornia. They are literally the kind of worm that little Willie adjourned to the garden to eat. Dr. J. M. Aldrich, of the National Museum, ate some of this food, and he describes it in the following language: “They taste like linseed oil. When properly prepared, they look something like a date, but the odor is slightly more pungent.” We are not clear as to what the doctor means by “‘properly prepared,” but we feel almost sure we would not like them. Turning Sewage into Power ROM Australia comes a plan to generate a septic gas from the sewage of towns. The British Ministry is investigating the claims of the inventor as to the yield from this source. Analysis of the gas shews that on an average it consists of 60 per cent methane, 17 per cent nitrogen, 8 per cent hydrogen, 14 per cent carbon monoxide, and 1 per cent oxygen. Experts declare that there is no reason why, properly controlled, ad- vantage should not be taken of the bacteri- ological action of sewage in septic tanks. Tests made to determine the horsepower developed in engines resulted very success- fully. Don’t Destroy the Vitamines A BRITISH physician recently put 4 forth the novel theory that one of the causes of chronic malaria is a diet contain- ing an insufficient vitamine content. In his opinion, British housewives are too much addicted to boiling vegetables, and even fruit. Overboiling destroys the valua- ble vitamines. He points out that the French thrive on raw fruit. Members of the Lister Institute working

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children of to the same cause an Although sufficient among the undernourished Vienna ascribe epidemic of scurvy. vegetables were provided to supply vita- mines in the proper amounts, the epidemic was unabated. Investigation finally placed the responsibility on overcooked vegetables and the dietitians recommended steaming. What Alcobronze Is OSSESSING the luster and color of gold, stronger, tougher, and harder than ordinary bronze, a new alloy of copper and aluminum bids fair to have a wide use. The new metal has been named alcobronze. It is stated by its sponsors that the new alloy can be wrought, forged, or rolled without deterioration. It also resists the action of the air, acids, and salt water. This makes it particularly suitable for forgings, propellers, and other ships’ parts. Oil Shells to the Rescue IL thrown on the waves will calm them. Hence it has been suggested that oil shells be fired from life-line guns in the coast guard stations, to calm the waters around stranded ships. If the oil shells are hurled well to the windward of a ship, and are made to ex- plode on contact with the water, the oil will soon drift around the ship and make it possible for a life-boat to be launched in safety. : An ideal oil shell would be one that could carry a gallon of oil. Clouds that Airplanes Make N airplane, flying high, will form a 4% cloud. The temperature is very low, particularly at a height of thirty thousand feet. The atmosphere is often saturated with vapor, and it needs some disturbing influence, such as an airplane, to start clouds forming. At Munich, recently, an airplane was flying at a height of thirty thousand feet. In front of it the air was clear, but behind it formed an ice cloud thirty miles long. Lost—Five Billion Dollars HE indestructibility of the standard precious metals, gold and silver, is demonstrated, says Dr. George F. Kunz, by the finding, at various times, of treasures of gold in earthen pots dating from five centuries before Christ, which are abso- lutely as they were when they came from the mint. Gold and silver have been used for coin- age for twenty-five centuries. There have been used at times, as mediums of ex- change in various parts of the world, corn, rice, salt, cocoanuts, dates, shells, shark’s teeth, and wampum, but these have had a local value only. Up to the present time in the world’s history, seventeen billion dollars in gold has been mined, of which five billion has been lost, leaving twelve billion dollars in circulation and in the arts. Taking the Dust Count OW much and what kind of dust flies in the air of a particular industrial plant? This is a question that can be answered only by a minute examination of - the dust, which is called “taking the dust count.” To determine how unhealthful the air dust of a particular plant process may be, after the composition is ascertained its effects are interpreted by standard tables prepared by the United States Public Health Service. This knowledge is very important, inas- much as certain amounts and kinds of dust seriously affect the lungs and predispose the workers to tuberculosis and other diseases. Two Lives for Stationery 7 VEN the best and most expensive letter-paper is considered worthless after it has been written on with pen and ink. It ends its existence in the fire or in the ash-barrel. A German inventor, stimulated by the scarcity of paper of any kind in his country, has patented a method of reclaiming used writing-paper. The sheets are passed in rapid succession through four baths, the first consisting of 25 parts of water, 214 parts of oxalic acid, and 2!% parts of glycerin, all by weight. The second bath consists of 25 parts of water in which one quarter of one part (by weight) of perman- ganate of potassium is gradually dissolved. To make the third bath, 2% parts (by weight) of acetate of lead are gradually dissolved in 25 parts of water. The fourth bath is a solution of sulphate of aluminum in water. After the paper has passed through the four baths, the paper is squeezed between rubber rollers to remove the liquids con- tained in it, and is then dried and smoothed out, being run between hot rollers. Crushing Germs to Death H-4t ultra-violet light, ozone, and high-frequency currents are all death- dealing forces to microbes and bacteria. High pressure has recently been added to this list by Professor B. H. Hite, of the University of West Virginia. When a pressure of 315,000 pounds is brought to bear upon a bacteria-infested substance, there is nothing left but a harmless mass of protoplasm. The appli- cation of this tremendous pressure in no way alters the taste of the substance treated, whether it be milk, cider, or grape juice. No microorganism has yet been found that is capable of withstanding 315,000 pounds pressure; many perish under 100,000 pounds. Professor Hite’s mechanical process of sterilization is very simple. The germ- bearing substance to be treated is placed in a steel container or cylinder built to with- stand the high pressure used. A piston fits into this cylinder, and the high pressure is applied to the opposite end of this. Milk treated with this germ-destroying process retains all its flavor. Pasteuriza- tion of milk brings about an unnatural 72 Popular Science Monthly taste that is objectionable, and kills the vitamines without which disease would be produced. While, from the laboratory standpoint, the system has been a success, Professor Hite is not sure at this time that his high- pressure process can be applied commer- cially. The Perfect Climate RE _ health’ resorts healthful? Pro- fessor Robert D. Ward, of Harvard University, declares that it is fortunate for the general health that most of us cannot afford to visit the resorts. He follows up this strange opinion with the following explanation: ‘The best cli- mate for most people most of the time is one that has frequent moderate weather - changes, fairly marked annual and daily variations in temperature, a reasonable amount of cold during a part of the year, a refreshing variety in the way of cloudiness, and sufficient rainfall to provide enough moisture for the growth of grasses and crops.” Professor Ward confesses sadly: “There is no such thing as a perfect climate.” When It Rains Money VERY farmer knows that a drought destroys crops worth millions. But has the farmer ever calculated the money that is put into his pockets when the rain- fall is abnormal? One inch of rainfall above three inches in July increases the value of the corn crop by $160,000,000 in Indiana, Illinois, Kansas, Iowa, Ohio, and Nebraska. When the July rainfall averages less than 3.4 inches, the yield of corn averages ten bushels less an acre than when it is more than 4.4 inches. The increased value is about $250,000,000. The increase in the value of the wheat crop in the Dakotas, California, Washington, Kansas, and Nebraska is represented by $15,000,000 for each inch of rainfall above four inches in May and June. Now you know why the grain speculators watch the weather reports. New Airship Fabric Needed A ZEPPELIN airship, as every one knows, consists of a metal frame within which from fourteen to nineteen balloons, filled with gas, are caged. The frame is covered with a fabric that is trans- luscent but not transparent. A beam of sunlight can penetrate to some extent through both the outer frame fabric and the fabric of the inner balloons. The result is that the effect of a greenhouse is produced. In other words, the green- house acts as a trap for heat. And so it is with an airship. The gas is heated and expands. If the expansion is too great, it must blow off to prevent bursting of the balloon fabric. Why has not some one devised a light woven fabric that is not transluscent? Perhaps an opaque fabric could be pro- duced. The fact that Edison has produced nickel thinner than paper, and had a book printed on it, suggests possibilities. i meade Ecka wan aan Cn

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May, 1921 Samsons of the Twentieth Century i Herr Glasser, pride of the German circus, proves that he has more horsepower than the automobile to which he is tied. The motor is running in low gear, yet this man prevents it from moving. — tp tarareene snare: —, all “ Herr Glasser seems to enjoy being run over by an } 0 peat Here’s another strong man—Karl Moerke. Though automobile; one of the occupants of the car appears he’s short and stout, he is able to lift a four-hundred- more worried than he. Glasser finds it stimulating. pound weight with his shoulders How about his ribs? They are not even dented © Kadel & Herbert © International Film Service Piano-movers are always husky individuals. It takes James White, of Massachusetts, takes the bit between at least two of them to move a piano. Yet here you see his teeth and pulls a touring-car down the street. He M. Verhaert, a Frenchman, lifting four pianos—3000 wears a leopard skin across his chest—to denote pounds—at one time strength, undoubtedly

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Phe ee on than a minute. ELEVATING LEVER ELEVATING FRAME WORK The other plunger is blunt-ended and serves to close the link of the new cross-chain after With the help of runways, this new and simply operated dumping body is specially adapted to loading freight-cars It’s Easier than It Looks _ the aim of making a few parts do the work of many, a motor-truck maker has developed a dump- ing body that can be tipped in the usual manner, or raised and tipped at the same time. it has been insert- ed into the side chain. If youhave kept account of time spent in mending chains, you will re- alize the value of this machine. The new body is elevated by a hydraulic hoist, the additional elevating mechanism consisting of an extension elevating frame with a main elevating lever framework pivoted to the elevating framework at its midpoint and operated by pull rods and cables from the hoist. A body of this type is especially adaptable for work where the load has to be dumped at a height from the ground, as in chuting coal into shed windows or hoppers, dumping con- crete into mixers, or depositing garbage into tanks or vats. Helping the Gasoline to Be Doubly Effective NE of the newest devices for vaporizing gasoline in automobile engines consists of an aluminum heat jacket that connects the carburetor with the intake manifolds. An opening at each end of the jacket connects with a like opening in each of the exhaust manifolds. With the first explosion of the engine, hot exhaust gases are forced through the jacket. The thin walls of the jacket allow the heat to be transferred to the gasoline, which enters the superheated vapor- izing chamber and is drawn into the cylinders, a highly volatile gas. p ‘ y i 4 | CARBURETOR | q 2 q C QV) P2745 Wa) | exaust © fj} GAS g > WD > INTAKE TO ENGINE ~~ This tilting headlight, designed to reduce glare, is tilted by the auto- mobile engine. It is controlled by the driver from the automobile’s instrument-board By utilizing the exhaust gases, gasoline enters the cylinders in the form of a volatile gas 74 Popular Science Monthly Rapid Mending of a Skid-Chain EPAIRING automobile skid-chains has hitherto been done by hand with pliers and a hammer. Gevised machine is almost automatic in action, and will insert a new cross-chain in place of a broken one in less It is claimed that the machine and one man will do the work of six men without it. The apparatus consists of two plungers mounted in a frame fastened to the top of a bench. moved back and forth by a lever extending through the bench and operated by the foot of the mechanic. One plunger is sharp-ended, and serves to cut the link of the broken cross-chain where it connects with the side chain. A recently The plungers are This little machine quickly inserts a new cross-chain in place of a broken one in less than a minute The Automobile Engine Tilts the Headlights ORMERLY an automobile engine merely propelled the car. Later its power was harnessed to drive the generator; to charge the storage bat- tery for lighting and starting; to drive an air-pump for inflating tires; to operate a horn, and to work the vacuum fuel-feed system. Now comes an inventor, Samuel F. Arbuckle, who makes use of it to tilt the headlights downward to eliminate headlight glare. Each headlight is operated by a small bellows inside of the bow] of the light, the bellows being filled and emptied of air by the partial vacuum created in the engine by the suction stroke of the pistons, operated by a system of rubber tubing and copper piping leading from the bellows to the top of the engine-cylinder block and to a control lever mounted on the instru- ment-board. The inventor of this new lamp has contrived to tilt the reflector portion of the lamp by utilizing the engine suction. The movable reflector and its com- ponent parts may be operated and controlled from the instrument-board even when entirely removed from the lamp-shell and held in the hands. When in the tilted position, the lamps brilliantly illuminate a space twelve feet wide directly in front of the car with none of the dazzling rays of light extending more than forty-two inches above the level surface on which the car stands at a _ point seventy-five feet or more ahead. In the upward position, the lamps illu- mine the road and the sides of the road for two hundred yards. May, 19 F you the ford s grind know t procedt one va With t machir valves grounc the m only f¢ ent, 0 other way. The sists carry] rack, turne hand] forth engin ratus block clam perm back TI spin 7 hea’ of | pen ope ma. one wei pot the an of mo sto pre

Page 55

, w@ OS KY wy ww DH. ~~ W@W Se SS 6 CC Grinding All the Ford Valves in One Operation F you have watched the mechanics in a Ford service station grind valves, you know that the usual procedure is to grind one valve at a time. With the use of a new machine all eight valves may now be ground at once. While the machine is made only for Fords at pres- ent, new designs for SPAN NER HOLES AW VALVES with the machine, is placed under each valve. While all of the valves are ground at the one setting, the actual grinding is not all done at the same instant, since only two of the valves will be down on their seats at one time. When the remaining valves are off their seats by rea- other cars are under way. The apparatus con- sists of a framework carrying a steel-tooth rack, a series of eight bronze gears turned by the rack, and an operating handle to move the rack back and forth. After the cylinder head of the engine has been removed, the appa- ratus is fastened down to the cylinder block by means of dowel-pins and a clamping-nut on a hinged bar, which permits the framework to be tilted backward to examine the valves. The eight gears are carried on short spindles surrounded by coil springs Industrial Truck for Foundry Haulage HIS electric truck for handling castings from the molds to the heat-treating ovens has the advantages of low operating cost, mechanical de- pendence, and great mobility. It is operated by a storage battery and makes about four hundred trips on one charge. It carries covered pots of castings, weighing as much as four thousand pounds. These pots are picked off the floor and carried to the oven by an elevating platform at the front end of the truck and run by a separate motor drawing its current from the storage battery that feeds the truck- propelling motor. Instead of grinding one valve of your Ford engine at a time, you can grind all at once with this little machine shown tilted back gear-spindles and having small disks with projec- tions at their lower ends. Since the framework is turned upright about its hinge, these projections fit into the two depressions in the head of each valve. Then, as the gears are revolved about their axes by the movement of the rack, the valves are turned. Before the grinding is begun, each valve is smeared with a coarse grinding compound, and an_ under-the-valve spring, twelve of which are furnished LEVER This new safety stop for Fords, in- vented by a Syracuse engineer, does not depend entirely upon the skill of the driver STORAGE BATTERIES DRIVING WHEELS. b ELEVATOR RNOTE POT OF ge METAL OFF FLOOR) |. 7 +” Electric industrial trucks are not new, but this one is a great improvement over the earlier ones 75 Here the grinding machine is valves, showing the ends of the son of being pushed upward by the cam- shaft, the spindles of the gears are pushed upward against the coil springs surrounding them and thrown out of mesh with the rack. Thus the machine automatically picks out those two valves to be ground and turns them on their seats so that the grinding from the compound actually grinds them in place. After being ground, a half turn on the starting handle of the engine will turn the camshaft a quarter turn and thereby seat the two valves next in order to be ground. Make Driving Easier by This Safety Stop SYRACUSE engineer, George G. Porter, has devised a safety stop for Fords that makes it possible to thrust both pedals forward as far as they will go when a sudden stop is to be made. This action is secured by fitting a lever to the clutch pedal. When the pedal is pushed downward out of high gear, the forward part of the lever comes into contact with a stop. Concurrent application on the brake pedal stops the car. The safety stop is also of assistance in starting or reversing. When the car is not in motion, the clutch pedal is held in the neutral position by a cam actuated by the emergency brake lever. Without such a stop, the operation of starting the car is to push the clutch pedal forward sufficiently to take up all the slack in the parts, but not enough to throw in the low gear and hold it in this position while the emergency brake is released. With the safety stop this action does not depend upon the driver. He simply pushes the pedal down until the stop comes into play. Then, while the emergency brake is released, he re- leases the pedal slightly and rocks the foot forward and upward so that the toe engages with the latch and moves it forward to raise the end of the stop lever. This allows the clutch pedal to be pushed forward into lew gear.

Page 56

Popular Science Monthly

Some New Ideas for the Automobile Owner and Driver

Spare tires should be protected from air and moisture, which cause rapid deterioration of the rubber. Painting tires with a liquid preparation re- cently invented is an effective protection easily applied

carry extra water, gasoline, and lubricating oil. The carrier shown here has three contain- ers, held together by steel straps, and fastened to the running-board On long tours it is prudent to |

A development of the motor- cycle side-car is the taxi shown here, in which the unprotected side-car has been elaborated into a closed cab giving ample protection from the weather

What the stethoscope is to the physician, the electrical instrument shown here is to the mechanic trying to detect and locate engine defects of the automobile

With the formidable drop fender for automobiles and motor-trucks here shown, the inventor hopes to reduce the number of fatal accidents to ORE W-THREADED pedestrians on streets and ih RE VALVE country roads f

FAN-SHIFTER SPRING

Screwing down the nut that holds the valve-stem EXPANSION - ei of the inner tube is tedious, owing to length of <Y LINDE stem and smallness of thread. This machine = . does the work in a few seconds

When an engine back- fires while being cranked, it means a broken arm or wrist, unless the operator is an expert. The catch shown here stops the crank from moving in the wrong direction

To prevent curtains sagging and flap- Glaring sunlight may be kept out of the

This fan has revers- / ible blades that will § blow hot or cold air : through the engine ; radiator as required. The blades are shifted by an arm ; that is actuated by : a thermostat

PPAR. sche etalon ra

ping and being worn out by the curtain- eyes of the driver by a curtain in front rods, the rod thimble here shown has of the windshield. It is raised or been invented. It can be attached lowered by a lever connected with without tools the frame

—————

pe a eae See ee

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-vers- t will ld air ngine uired. are arm d by pint iba Aces May, 1921 Do You Want Advice About Your Car? OUBTLESS you have received many a hint about the care of your automobile or motor-truck from the Popular Science We realize, however, that special cases require special advice. invite you to send your problems to the Auto- Monthly. We therefore ask questions. answered on page 80. mobile Editor, who will be glad to answer you. If you wish to know more about the devices pictured on these pages, or if you would like special automobile advice of any sort, You will find some inquiries ? INVERTED PENDULUM ON VALVE HEAD SELF-CLOSING VALVE » When the automobile is still, this inverted valve- cone shuts off the oil A radiator of hexagonal brass tubes with double walls two thirds of their length “DOUBLE WIRE- q/ TESTING'CORD -_ With the small electrical tester illustrated here, wiring circuits of automobiles, motor-boats, telephone lines, etc., can be effectively tested. A lamp, a buzzer, or a tele- phone microphone will betray any defect or short-circuiting Only when the automobile is in motion will this simple oil- cup feed oil to the bearings. The oil is splashed against the top of the cover, flows down to the tip of the inverted cone, and drips through the Y feed-pipe to the bearings TO BEARINGS 1997 i Small mirrors mounted on ball-and- socket joints are used advantage- ously to illumine the dials of the various indicators on the instru- ment-board of the automobile at night. They reflect the light of the cowl lamp on the dials | Los Angeles boasts of the garage shown above. You may drive your car into the garage and repair it yourself, or you may hire a mechanic to do the work, paying so much for space, tool rent, or labor hire, as the case may be There is safety in this type of speedometer, which is mounted on the steering-wheel and has graduations and figures painted with a radium compound so that it may clearly be read on the darkest night 77 be ee ——— ann The centering device for lifting-jacks which is here shown consists of two plat- forms movable in grooves at right angles to each other. Heavy loads may be moved short distances with the aid of this device This indicator shows if your engine is becoming over- heated. The apparatus is wired to a thermostat at- tached to the engine. Nor- mally it shows a green light, which is supplanted by red if the engine gets too hot By connecting a condenser with the radiator, the loss of water by evap- oration will be greatly reduced, as the steam is changed to water in the condenser and, having been cooled, is drawn back into the radiator, keeping up a continuous circulation

Page 58

SLOTTED GUIDES HOID GIA TO HC OLA PLATES IN PLACE ~

In this new truck body the glass is carried vertically; slotted guides and _ other safety arrangements are pro- vided as indicated F all kinds of fragile com- modities handled on motor-trucks, that commodity which is probably most sub- ject to breakage is plate-glass in large sheets for windows. Plate-glass com- bines great bulk and awkward shape with extreme fragility. It is because of these conditions that the adaptation of the motor-truck to this class of work has for so long remained a prob- lem to body-builders. The main difficulty in the construc- tion of a satisfactory body for handling glass has been to get the floor of the body low enough to remove the glass without lifting and without placing

Here Is a Truck that Was Built Especially to Carry Plate-Glass

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esis ee <a LONG RUNNING-BOARD A Chicago firm has successfully solved the problem of carrying plate-glass with this truck specially designed for this kind of transportation the truck frame beneath the rear axle. The underslung frame has many dis- advantages and has never proved en- tirely satisfactory. The problem has at last been solved by a Chicago plate-glass company by mounting the body directly on the frame of the truck so that the body floor is only thirty-two and a fraction inches above the ground when the truck is loaded. The distance between the body floor and the ground is just the normal height of a man’s hand, so Measuring the Farm Tractor’s Work NTIL the development of the work-measuring instrument that is shown herewith, the farmer had no means of telling whether his tractor was performing all of the work that could be expected of it. If he decided that a three-plow tractor was most suitable for his requirements, he had to take the manufacturer’s word for it that the tractor purchased could pull three plows without putting undue strains upon the tractor. He had no ready means of determining whether the tractor could pull four instead of three plows under his particular soil conditions and thus do one quarter more work, or whether he should use only two plows. With the new instrument he need not rely on guesswork. The instru- ment consists of a coil-spring connec- tion between the tractor and the im- plement that it is pulling, be it plow, harrow, or other tool. The pull re- quired to haul the implement js re- corded on a dial that forms a part of the instrument, and each dial is gradu- ated by previous tests according to the maximum pull that should be delivered by each individual tractor. The reading on the dial may be seen by the tractor driver while sitting in his seat, so that he may tell at once whether or not the tractor is over- loaded. The dial is further connected with a release that automatically breaks the spring connection between the tractor and the tool it is pulling when the pull exerted reaches a predetermined ex- cessive amount. For some makes of tractors, one of the instruments may be set to release for two, three, and

How the instrument is placed on the tractor: it records the pull on a dial 78 Popular Science Monthiy

The truck is no wider than an ordinary motor-truck, and the floor is only thirty-two and five eighths inches from the ground that the plates may be loaded and unloaded without lifting. The sheets of glass are car- ried vertically instead of hori- zontally, and not one of the sheets carried during the first year’s opera- tion of the truck was broken. Carry- ing the plates vertically makes it pos- sible to get the largest size into the body, although the latter is easy to maneuver because it is of ordinary width. The plates of glass are kept from shifting while in the body by slotted guides with felt-covered ends that press directly against the glass, as indicated in one of the accompanying illustrations. This measuring instrument tells the driver how hard his tractor is working four bottom plows at 4000, 5000, and 6000 pounds drawbar pull, which is the average maximum pounds pull that should be exerted by the tractor before releasing. The instrument has an added advan- tage in that the use of coil springs provides a cushion to take up starting strains otherwise transmitted to the tractor.

May,

one J the t him. Ta three groce try t depa smal his | or tk mair are | Causi tain tons grea’ truc! othe cost keep who kno\ trut! T truc whil sma ing | mile

Page 59

"= ee — -S_ SS

| May, 1921

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owned truck in the hollow of his hand. Because the driver is the one person who is actually with or on the truck, success or failure lies with him. Take any owner who operates two or three trucks. He may be a retail grocer in a large city or a small coun- try town; a florist; a laundryman; a department-store owner; or even a small manufacturer. No matter what his business, if he operates one, two, or three trucks, his problems of truck maintenance are the same. And these are his most important problems; _ be- cause the cost of operating and main- taining any truck, from one to five tons in capacity, is yearly equal to or greater than the initial cost of the truck, its body, and equipment. In other words, it is not so much the first cost that counts, as it is the cost of keeping the truck running. Any one who owns a passenger automobile knows from experience that this is the truth. The same holds good with the motor- truck, but to a greater extent, because, while a passenger-car is in use only a small part of the year, a truck is work- ing every day and covers a far greater mileage. "os driver holds the individually Pay Only for Actual Repairs The owner who operates one, two, or three trucks cannot afford to hire an extra man to look after the trucks or build a garage or machine-shop where vehicles can be given the mechanical attention they need. The fixed charges represented by the cost of a man to look after the trucks and a mechanic to repair them would be too great when spread over from one to three trucks, even though it might be good business January February

yy OL) a sta U j (, [iN oF aw R

Men who operate a fleet of trucks usually employ a mechanic to look after them; if there were ten or fifteen or more trucks in the fleet. Because of this, the owner is forced to keep his trucks in a public garage, or in a building on his own property if such is available, and to depend for repair work upon the local truck- dealer or manufacturer’s branch from which the trucks were originally pur- chased. This is the cheapest method in the long run, because the owner pays only for the actual repair work done, which includes the actual cost of the work and new parts installed plus the profit of the dealer or branch agent. This would be less than the salary of a mechanic employed all the year round, because the maintenance work on two or three trucks could not possibly keep such a mechanic busy for the year. Some truck-owners have been able otherwise to solve the problem by utilizing intermittently the services of a mechanic in their own manufactur- ing plants or shops, or of a private mechanic who has time to spare. Other owners have taken advantage of the truck-maker’s offer to send an in- spector once a month or more to go over the trucks and make a report on their condition. Still other owners have been able to secure a driver who was enough of a mechanic to adjust and repair the trucks when his own truck was not engaged. But such repairmen are few and far between. It is the consensus of opinion, derived from the experiences of a great num- ber of users, that the driver should drive and the mechanic should repair. In many cases this decision has been reached only after bitter experiences in which drivers who claimed to be mechanics have tinkered botched the work so that more money was spent ————

lk tet PE Au? : JAP

May June July

March April =) VOIR (2 3 SVORE || svorRe || SToRe TT

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and <= =" It’s Not the Cost of the Truck, But— The cost of keeping the truck running By Joseph Brinker but the owner of one, two, or three trucks is dependent on his drivers to watch out for signs of wear than if a real mechanic had been em- ployed in the first place. But, no matter in what manner the maintenance is provided for, the solu- tion of the problem always reverts to the driver and the degree of care he gives his truck day after day. No mat- ter what the business of the owner, be he grocer, florist, or manufacturer, his main interest is in selling groceries, flowers, or his manufactured product With him trucks are but a means to an end, although they play an important part in helping to show a _ business profit at the end of the year. No One to Check Up the Driver As soon as the driver leaves the store or plant, he is out of the sight of the owner. The driver is then in complete charge of an expensive piece of ma- chinery. Whether the driver over- speeds at times and loafs at others, jams on the brakes suddenly, lets in the clutch too quickly, does not change speeds properly, or concentrates the load at one point, the owner cannot tell until the repair bills come in, unless he employs some form of daily driver’s report, which will indirectly indicate trouble before it actually occurs. So, in truck repair, the most difficult work is not the actual maintenance, but the inspection or report that indi- cates what parts should receive the mechanic’s care. With a large fleet the owner can afford to hire an in- spector to collect this information for him; but with only two or three trucks he must find some cheaper method ot obtaining the same data. It is the ounce of prevention instead of the pound of cure that cuts the cost of truck maintenance. A stitch in time, which eliminates a squeak October November Dece mber

By constant watchfulness, the wise motor-truck owner keeps his truck or trucks moving eleven months of the year, and uses August, the slack month in business, for repairs 79

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before it has become a rattle, is what keeps money otherwise spent for main- tenance in the owner’s s pocket. Just how important it is to eliminate the small ailments before they can grow into big troubles can be shown by one instance: Imagine a truck costing two thousand dollars, and which, through indifferent care on the part of the driver, has worn out in three years. In depreciation it cost $666 a year. If, by good care, the same truck were made to last five years instead of three, the annual de- preciation would be only four hundred dollars a year, or a net yearly saving of $266—enough to pay the driver’s wages, at thirty dollars a week, for almost two months! This is worth saving; but how? Daily Report Card Here again the owner must de- pend on the driver; for, while he may know little or nothing about the con- struction of his truck, he is in a better position than any one else to report on its behavior. Experience has shown that the best method to get this infor- mation from the driver is by the use of a driver’s daily report-card. For the owner operating two or three trucks the report-card must not be made too simple. If it is too simple, the driver may omit reporting some small ail- ment that would be caught by the in- spector in charge of a large fleet. The driver, in the case of the small fleet, must become kis own inspector. But, because he is not a trained mechanic, the type of questions that he must answer on his report-card should be made simple and general, rather than specific and _ technical. Suppose, for example, the owner asked the driver to answer questions on the card such as: ‘‘Are the valves seating properly?” or “Do the magneto or dis- tributor breaker points need adjust- ment?” In nine cases out of ten, the driver could not intelligently answer such questions because of bis lack of me- chanical and technical knowledge. But if he were asked: ‘‘Does your engine lack power?” he could imme- diately answer “Yes” or “‘No.” At first glance this question might seem entirely too elementary and the an- swer of no value. But if the driver re- ported that his engine lacked power, Popular Science Monthly to the more intelligent owner it would at once set up a train of thought as to the reasons for loss of power, which might include leaking valves, improp- erly adjusted breaker points, broke spark-plugs, too lean fuel mixture, in- adequate lubrication, and other cause: Questions that Save Money Such questions as: ‘Does your clutch engage smoothly?” ‘‘Are your brakes working properly?” and ‘Dos your truck squeak and rattle?” can hy easily answered by the driver and ye: definitely reveal the condition of the truck. Clutches that grab and brakes that are worn need immediate atten- tion, and squeaks and rattles indicat: a lack of lubrication just as surely as i! a sign inscribed ‘‘We need oi!” hung from every bearing. were It is such questions as these, and others asking the mileage run, the gas- “Are the oline and oil used, and grease-cups full?’ empleyed with maker’s chart bearing or part is to be oiled or greased which are the prevent excessive motor-truck main tenance costs. showing when each “stitches in time’”’ that Soda to Clean the Radiator Q.—Please tell me how I should use soda to clean the circulating system of my en- gine?—K. M., Paterson, N. J. A.—Mix ¥% lb.-soda and 5 gals. water. Strain the solution and then pour into the cooling system, which has been previously allowed to drain out. Run the engine fora few minutes and drain out the solution. Next, pour in some clean water, run the engine again, and drain it out. After this draining, add more water and run the engine as usual. Kerosene Will Remove Carbon Q.—Will kerosene remove deposits of car- bon on cylinders if admitted in the air intake or carburetor while the engine is running ?—G. M. D., Akron, Ohio. A.—Kerosene introduced into the in- take manifold will tend to loosen the carbon in the cylinders if the carbon has not become too hard. Too much kerosene should not be introduced at a time or too often, as it is liable to cut the lubricating oil. A Tire Gage for Compression Q.—In several of your back issues I have noticed drawings showing the use of a tire gage inserted in the engine petcock to in- dicate the a pressure. Will you please tell me if the use of a tire gage in this manner will give a correct compression pressure?—M. M., New York City. A.—The use of a tire gage in the man- ner you mention will give the correct compression pressure if the tire gage is correct and the engine is turning over at a good rate of speed when the gage is used. Proper Clearance for Pistons Q.—What is the proper clearance of cast- iron pistons in automobile engine cylin- ders?—R. X., Detroit. A.—Piston clearances vary in gray cast-iron pistons from 0.003 inches for each inch of the cylinder bore at the head of the piston to 0.002 inches be- tween the first and second rings, and to 0.001 inches on the lower portion of the piston. Two- vs. Four-Cycle Engines Q.—Please explain why the two-cycle motor, used almost exclusively in the first automobiles, has been superseded by the four-cycle type.—J. B., Chicago, III. A.—The four-cycle gasoline engine has superseded the two-cycle engine for automobile use because, through the greater development of the former, it consumes less fuel for the same power, is more flexible, and is subject to less trouble with cooling, lubrication, and carburetion. Fluxes for Soldering Q.—Will you kindly tell me what are the best fluxes to use for soldering weer to brass parts and brass toiron parts.—K. C. B., Kalamazoo, Mich A.—The most tomeaianel workmen prefer borax and sal ammoniac, the for- mer being employed when the job isa difficult one, such as soldering a small part to a large container, which tends to extract much of the heat of the solder- ing-iron. Either borax or sal ammoniac removes all the foreign substances from Write to Us About Your Motor Troubles If you have a motor-truck or automobile problem, let the Automobile Editor solve it the soldering-iron and makes it pos- sible to cover it thoroughly with a coating of lead. Detecting Acids in Oil Q.—Will you please advise me whether there is any simple method of telling if there are any acids or alkalis present in lubricants such as used on trucks and automobiles.— D. S. H., Philadelphia, Pa. A.—Litmus paper is the most simple test for the presence of acids or alkalis. Commercial litmus paper may be pur- chased at almost any drug-store. Blue litmus paper when immersed in_ the lubricant will turn red if any acid is present. Similarly, red litmus paper will turn blue if any free alkali is present. Why the ‘8’’ Runs Smoothly Q.—Please explain in simple terms why an eight-cylinder engine is smoother running than a four-cylinder engine.—S. G., Brook- lyn, N. Y. A.—The eight-cylinder engine is smoother running than the four be- cause it gives four explosions per revo- lution of the crankshaft as compared with but two explosions per revolution of the crankshaft in the four-cylinder design. The power impulses transmit- ted to the crankshaft are more fre- quent in the eight-cylinder engine and this tends to reduce the necessary weight of the flywheel, the purpose of which is to keep the engine running smoothly from one power stroke or ex- plosion to the next. 80 | fay, The ‘THI i kn du: mour ps, lect small ind tl equip} power cleane troubl premi: combi tainec Ass stallec will | Secon cheap build made rivete ings stant drivil kee A shou moti fron T can sho] tion hau: ben shee spec for | pipe by 1 und allo

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‘fay, 1921 The Vacuum Cleaner in the Small Garage T= owner of a small shop or garage knows the amount of trouble caused dust and dirt, especially if he does any amount of wood-working. If shavings, ips, and other refuse are allowed to lect, it is easy to lose tools and other small articles, good work cannot be done, and there is danger of fire. If the shop is equipped with a small motor of 14 horse- power or more, a stationary vacuum cleaner can be installed without much trouble; if no motor is at hand and the premises are wired for electric lights, a combined blower and motor could be ob- tained. Assuming that a motor is already in- stalled in the shop, the first thing necessary will be to obtain a small fan blower. Second-hand blowers may often be bought cheaply, or, if the shop-owner wishes to build one himself, a blower case could be made of galvanized sheet iron, soldered and riveted together. The impeller and bear- ings could be bolted to a separate sub- stantial base. Provision must be made for driving the blower at the required speed, SHOP PARTITION

EXHAUST

SLIP JOINT LEATHER ORT RUBBER PLAN VIEW SLEEVE EXHAUST BIN FLEXIBLE JOINT rd INTAKE PIPE ’ RUBBER EA eee “HAFLEXIBLE CORNER NOZZLE BENCH —~y JOINT SOLDERED H JOINTS } GALVANIZED «¥ |RON CONE

GALVANIZED IRON NOZZLE

Pay ~ VACUUM HOSE This arrangement of a suction cleaner will be found practical in most garages which for a small one is in the neighborhood of 4000 r.p.m. As lar ge a blower as possible as determined by the power at hand, should be installed. A 1/16-horsepower motor will drive one having an impeller from 6 to 8 in. in diameter. The blower is placed so that the exhaust can be carried out through the side of the shop into the open air, but in such a posi- tion that the piping, both intake and ex- haust, can be as short and have as few bends as possible. Light tin or galvanized sheet-iron piping is used, though there is no special objection to using regular iron pipe for the exhaust line. All joints in the intake pipe must be tight and this is best insured by running solder around them and testing under air pressure, if this is possible. To allow a certain am ount of flexibility to the inlet pipe and yet keep it airtight, one or more rubber or leather joints may be in- Stalled so as to allow a greater “reach” to the cleaner hose and nozzle. A length of Inner tube about 8 in. long is suitable, or Sieet rubber or leather with cemented joint can be used. The sleeve is bound to the pipe with a wrapping of copper or soft iron wire. At the lower end of the intake pipe a long cone, made up of sheet galvanized iron or tin, is soldered. A sleeve soldered to the small end of the cone takes the cleaner hose, which is one of the regular pieces of equip- ment of the electric vacuum cleaner and may be bought separately in about a 9-ft. length. The nozzles used can be bought also, but can be easily made from galvanized iron. The illustration shows one with a square end for reaching into corners. How I Made a Temporary Valve-Spring Repair AVING broken an exhaust valve- spring on my motorcycle when I was miles from a repair-shop, I hit upon the following simple and effective way of re- pairing the dam- age. Taking from

xj the toolbox an iron washer hay- ing an _ outside diameter slightly

——£ Cee BROKEN <— —=— / SPRING p& WASHER larger than the coiled spring,. I placed the wash- er between the two sections of the spring, let- ting the valve- CY stem pass through the hole in the washer. This apparently operated as well as a new spring; in fact I rode the motorcycle several hundred miles before replacing the broken spring with a new one.—H. E. PAGE. Old Tires Used for an Anti-Skid Device cy the various ways to utilize worn-out pneumatic tires, one of the most satis- factory and practical is to cut them up and use them instead of chains as anti- skidding devices. To utilize the | tire as a chain, first make about eight or ten clips —four or five for each wheel —as shown in the il- lustration. These consist of pieces of band iron about 14 in. by 6 in. long, with a 5/16-in.hole drilled in each end and bent as shown with about a 1-in.

BROKEN SZ SPRING How a broken valve- spring was repaired

p~< opening. Then a SECTION OF/ 5/16-in. machine- OLD TIRE bolt is inserted in These strips grip the ground and prevent skidding the ends and the clip is complete. Then the good part of the tread is cut into strips about 114 in. wide and long enough to go around both the tire and felloe and project about 2 in. The clips described above are used to fasten the ends of the strips as well as to hold them in place.—S. O. NAFZIGER.

81 A Warning Light Means a Hot Engine ELOW is an illustration that shows a homemade and very effective hot-motor alarm. Any car owner with a little mechan- ical ability can easily build one. The sketch shows a section of the radiator at the top of the water chamber. The main tube of the thermostat device is made of bakelite or one of the impregnated bakelite fibers that is water and steam proof. The top of this tube is threaded into a bracket which is in turn soldered into the neck of the radiator. The lower end of the tube is also threaded into the mercury chamber which is made of fiber. This chamber is locked and made leak-proof with a nut. At the upper end of the tube is the contact which is provided with an extension con- tact of brass and which is also led out through a brass ribbon and soldered to the supporting bracket, thus making a ground connection on the ear. After the device is assembled the copper tube is soldered in place and a wire led out through it to a small lamp on the dash. The circuit is made through the battery circuit on the car as shown. The mercury chamber is threaded on to the thermostat- tube so that the device can be adjusted. This is accomplished by submerging it in boiling water and then setting it just a trifle short of making the circuit. In other words, when the water in the radiator reaches the boiling temperature, the motor CONTACT MOOD : | remnesa- HERMOSTAT DEVICE = L COPPER TUBE } | b g- WIRE Paes! a aa —il|—————- } DASH BATTERY MERCURY TOP OF RADIATOR TUBES

Iaaiconsinsaealagd When the engine becomes overheated, the driver is warned by the flash of the dashboard lamp

is dangerously overheated and needs atten- tion. At that point the mercury is so ex- panded that it rises in the tube and com- pletes the circuit, thus lighting the lamp. Find a Special Place for the Tire-Gage PLACE for everything includes a + place for the tire-gage, and instead of searching around the toolbox under the rear seat of the automobile for the tire-gage, take a small con- tainer such as a NAIL, shaving-soap y

ut a secti yh TIRE box, cut a sec tion I GAUGE out of one side Me and with a nail ; ? CUT OFF box . tool fasten the inside the se omtpaner METAL compartment. CONTA af The tire-gage, when placed there, can be lo- cated instantly when air is to be put in the tires.

Keep the tire-gage where you can find it

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Carry Chicken Wire on Your Motor Trips N certain parts of the United States you will find some pretty bad roads. Some of them are almost impassable for motor- cars in wet weather. A party of motorists encountered a section in a Western state where the soil was sandy and their heavy touring-car had considerable difficulty negotiating the roads, particularly as the ground was still wet after a heavy rain- storm. In many instances the sandy soil was so soft as to come up over the tires Wire fencing, such as used around chicken-yards, will enable an auto- mobile safely to cross muddy spots on soft country roads almost to the hubs, often preventing suffi- cient traction to enable them to keep going. i But the driver was of the inventive type and he hit upon an idea that may be of value to you when you encounter almost impassable roads. He obtained a roll of chicken wire wide enough to cover the tread of the car. Whenever a bad spot was reached, one of the car occupants proceeded to unstrap the roll from the rear of the car and stretch it over the bad piece of road. They would run over the wire and laugh at the deep mud lying in wait for those less ingenious. The wire prevented the wheels from sinking, acting on the same prin- ciple as snowshoes do when traveling over drifts.—F. G. JOppP. A Fastening for the Garage Door \ HEN building a new garage, many 'Y ecar-owners are at a loss to know how to fasten the bottom of the large swinging- doors with which are usually equipped. The fastening shown in theillustration has proved sat- isfactory and convenient. In pouring the cement floor, a short length of pipe was placed nearthe doorway garages and slightly to one side of the center. The pipe was placed This is a good fast- in a_-vertical ener for the swing- . position, its up- ing garage door per end_ being set flush with the top of the garage floor. The bar was made of a piece of round stock, the diameter making a sliding fit inside the pipe. One end of the bar was tapered and the other bent at right angles to form a handle. It was secured to the inside of one of the doors by means of two mild steel loops in which it could either turn or slide. When the door was being opened or closed, the bar was kept from dragging by a block at its upper end on which the handle rested. To lock the doors the handle was turned at right angles, so that it cleared the block and dropped into the pipe. The other door was then closed and locked to the first from the outside. A piece of pipe may be driven into the ground at such a place that the door can be held in the open position by the same bar.—L. R. BUTCHER. That Annoying Window Rattle Can Be Stopped PP SaqUenrLy the windows of a sedan or coupé will rattle, to the annoyance of the driver and other occupants. Loosening the guides or frames and moving them closer to the window will take out the rattle for a short time, but the results are only temporary and the windows are so difficult to open that a second person is necessary to go outside the car and push them in so they may be lowered. In the illustra- tion a_ simple attachment is shown that will silence the win- dow and also assist in opening it without assist- ance. It con- sists of a flat steel spring such as a piece of spring from an old alarm-clock or a corset steel. Put two holes through one end The pressure of the spring prevents a window’s rattling and screw this to the outside guide or frame so that the tension of the spring will push the window toward the inside of the car. This will hold the glass securely, and when it is desired to lower the window, the spring, pushing in, will press the glass free of the ledge while it is being lowered with the strap.—G. A. LUERS. Keep Your Brakes in Good Condition TOPPING to consider that your entire safety, especially in heavy traffic, de- pends upon the reliability of your car’s brakes, there is food for thought. Safety demands that the brakes be kept in the pink of condition. First, they should bind tightly and surely when pressure is applied, and be free and ride clear when the pedal or lever is re- leased. A brake shoe that binds when released, produces constant friction and makes hard running, besides wearing out the brake-lining. Slipping of the brakes is_ primarily caused by poor adjustment, oil between the surfaces, or worn linings. Poor adjustment can be remedied easily. Oily surfaces can be cleaned by taking out the shoe and cleaning with gasoline. Then the source of the oil leakage should be traced back and stopped. Oil generally 82 Popular Science Monthl) comes from the rear axle. A new washe will usually rectify this trouble. If the bands are too worn to allow an: readjustment, they will have to be re-lined Fabric linings are to be preferred to thos of leather, as the latter are apt to quick! burn out from the heat generated by cor stant application of the brakes. Sometimes, when the brakes are applie the car has a tendency to skid to one sid. This is an indication th at one wheel is bein braked while the other still runs free. Th» brake-rods should be inspected and the difference in adjustment equalized. Squeaky brakes usually indicate dirty linings. These should be cleaned with gasoline—then roughened with a _ wire brush. The dirt must be entirely removed from the pores of the fabric and a new sur- face presented to the brake-drum. Little lubrication of a brake-lining necessary—yet a few drops of thin oil once every few thousand miles will clear away any dirt and maintain a soft surface toward the brake-drum. Oil t he hinges, cams, etc., connecting the brake-r ods with the bands to reduce squeaking, c hatterings, and un- due wear. In the readjustment of your brakes, it is important to watch for the proper clear- ance. This can be any where from 1/16 to 1/64 in. all around. If the band clings to the drum at any point after sufficient clear- ance has been gained e verywhere else, then that particular point must be sprung slightly away from the drum by inserting a screwdriver or similar instrument between it and the drum.—L. B. ROBBINS. A Superior Tightener for Wheel-Chains CHAIN-TIGHTENER as illustrated “+ can be made in a few minutes from materials bought for a few cents at any repair-shop. Or, better yet, get down the box of odds and ends; possibly you already have all the material necessary. To make one set (two wheels) you will need: 12 to 15 feet of No. 8 wire. 4 springs 4 to 5 in. long, 1% to 34 in. in diameter. 12 small harness snaps. 4 harness rings, 34 to 1 in. in diameter. Select and snap in six snaps at equidis- tant points on the outside runner chain Cut and twist in wires as shown, making them long enough to clear the hub of the Chains cannot slip and chafe if they are held tight in the manner shown wheel. Hook the spring to the wires and tighten them, making them short enoug! to give a good tension on all three points o! contact. Repeat this for the other half of th« wheel and the arrangement will appear as shown in the illustration. Always place the tongue of the sna} toward the inside in order to protect it from stones, ete.—J. D. KING. roma spe Pree "rete Ye Raa ees [ the mak parture meé hod and ec rod of with it at the the bes said tk rod cc results. six Or one pé averag The being | tip sec piece : which castin; Exp tain w butt p ferules having center and tl ened. By center piece The hickc Y-in. while piece eylin¢ Don b Bs he ator, buildi sawdi ing a ceede Tw select inside all sic Th and move with heat- as sh Was to b the l the s

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——_— Se D | a= a x — To BD mae cs La —_ a (a a y 3— xa 64 t ——— ss

Double your pleasure in fishing by using a casting-rod of your own make fit in the butt piece of the rod. This is of hickory. A piece can be obtained in any lumber-yard. The illustration (D) shows the two pieces of the rod, the tip and the butt. The end of the butt piece that is fitted into the handle piece is 16/32 in. for 1 ft. of its length, then it tapers to 19/64 of an inch. Sink it in snug and tight and touch it up with glue so that it will stick. You will now have arrived at the point that is shown in B. The illustration (C) shows the butt end of the rod completed. In wrapping on the

At one end of the refrigerator shelves are provided on which to place dishes of shelves erected at icebox, on which preparatory to icebox. This crude refrigerator has been found to be scarcely less economical of ice than a first-quality manufactured article, and has proved generally satisfactory to its owner.—CURTIS RALSTON. of the could be set them in the one end dishes arranging Safety First in Opening Powder-Kegs EVERAL disastrous explosions have occurred—one at Sublet, Wyoming, which caused the death of six miners from driving a sharp-pointed hard-wood wedge through the top of a steel powder- keg. Experts assert that there is sufficient heat generated in driving the wedge to ignite black powder; that any method employed to puncture powder-kegs is ex- tremely hazardous and should be avoided. Opening the bung of the keg is the only safe practice.

»<- 83 green fishing-line, brush on a good grade of glue and soak the line with glue, too, so there will be no coming off. The butt cap fits snugly over the wound portion and is held firmly in place with two screws, one on each side, and one in the end if desired. The reel seat is then slipped over the 4-in. cylindrical portion and also is pressed home so that it covers the winding. Brush well with glue on the wood under the reel seat. Enough of this protrudes so that the bottle- neck taper fits over it, also to be screwed in place. When selecting the reel seat and the butt cap, remember that both are of the 34-in. grade, with the bottle-necked taper to match the reel seat. Since the action of the rod is thrown on the tip piece of the rod, it is well that that piece be of a high-grade material. Enough to say that bethabara is the best material to be had. A stick of 1/22-in. stock, 45 in. in length, will cost you probably 75 cents, and can be had from any well-supplied sporting-goods firm. See to it that this stick is straight grained and free from worm holes and rot places. The thickness of the rod is indicated in the drawing (D) at every 10-in. point. You will need a tiptop offset guide and three guides between the reel seat and the tip, one 5 in. below the jointing place in the center; the next one (proceeding toward the tip) 14 in. from that one; the third one 9in.fromthetip. To join the rod together, a male and a female ferule is needed. These should be of the 21/64-in. size. Select the capped and welted form. Every Garage Should Own This Distilled-Water Carrier O fill a battery from a large container of distilled water is not always con- venient. The practice of pouring distilled water from one container to another before the battery is supplied should be discour- aged as it permits of impurities getting in. The accompanying illustration shows a carrier with a l-gal. bottle that can be con- veniently carried from car to car. The sup- porting frame is made of 1/16 in. by 1% in. strap iron and riveted as shown. Four up- rights and a circular band make the frame. A handle may be fitted to two of the up- rights. The wire handle from an old pail will serve nicely. The stand is made of a wooden block to which the frame is screwed. A recess is turned into the block as shown. A block of rubber is fitted into this recess. This block of rubber is recessed to take the neck of the bottle, and a hole is drilled in the center of the recess large enough for a 14-in. rubber tube to pass through. The

pot c tube must be ce- Sma _- WATER BOTTLE mented into the BE CLAM rubber block in BOVE WATER order to prevent sa leakage. The Aox'/2 ria tube must be TUBE long enough to RUBBER reach to the top 4 BLOCK of the frame. If

WOODEN the tube is /BASE h : y/ clamped to the CEMENTED = top of the frame when not in use, a valve will not be required. Convenient for carry- ing water for filling batteries

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Popular Science Month'y Producing Queer Effects by Double Printing This composite picture was made by combining the two other pictures as described below ANY queer and amusing effects in photography may be _ pro- duced by masking, silhouetting, and double printing. The picture of a giant hen appar- ently taking a ride in an old fashioned automobile was produced in the man- ner described here, and will suggest other interesting combinations that may be obtained in the same or in a similar manner. The first picture shown is a com- bination of the second and third pictures. For making the prints, any of the commercial printing-out papers may be By Cora Hamilton used. The third picture shown was first printed very lightly. Then the negative was removed and a negative of the hen was placed in the frame so as to bring the picture of the hen in its place over the automobile seat. After a short exposure both pictures showed on the print, which was then ready to be used for the masks. The picture of the hen was carefully cut out of the picture with a sharp knife, leaving an opening representing the shape of the fowl. Then both parts of the cut-out were exposed to the sun to blacken them. Neither toning nor fixing was necessary. The negative of the car was next placed in the frame and the hen sil- houette was placed in the proper posi- tion between the negative and the sensitized paper so as to block out that part of the picture where the hen was to be. After the print was dark Biddy’s portrait was transferred to the print of the runabout by silhouetting it A Simple Force Pump Made from an Atomizer FORCE pump that is very useful for all sorts of small and light jobs can be made from the rubber bulb of an old atomizer. Take the rubber bulb, with the thin rubber tube to which it is at- tached; push a piece of bath hose over the rear end of the bulb and secure it in position by means of a tin strap and a nut and bolt, asin Fig. 1. You now have a complete force pump, the bath hose acting as intake and the thin tube as delivery. The pump can be still further im- One or two atomizer bulbs can be used for making a footpower force pump proved by adapting it so that it can be driven by crank or pulley, as shown in Fig. 2. Figure 3 shows a still further re- finement by means of which an al- most steady flow of air or water is obtained. Keeping Razor Edges Free from Rust PT HE writer has found by actual ex- perience that oil positively helps to keep razors sharp, whether they be of the ordinary or the ‘“‘safety’’ type. The best to use is a light and abso- lutely pure oil. An excellent manner of using it is to put it into a medium- sized bottle. In the small end of the cork make a cut with the small blade of a penknife; into the cut introduce absorbent cotton, previously rolled into a ball, to form a sort of dauber. Apply lightly the edge of the razor-blade to the moistened dauber. 84 The picture of the old-fashioned run- about that formed the foundation of the composite print enough, it was removed from the printing-frame and the negative of the hen was put in the frame. The mask from which the hen picture had been cut out was placed on the nega- tive so that it covered everything but the picture of the hen itself. The masked print was then placed face down on the negative so that the hen fitted exactly into the blank space of the print. Next the frame was ex- posed to the sun until the hen print was approximately as dark as the rest of the print. After toning and fixing the: print, the picture as shown was obtained. Insure an Attractive Show- Window HIS novel attraction for a show- window can be made out of pipe- fittings at smallexpense. The pipe is of 3¢-in. stock. At points a and b in the stem a hole is drilled which should be no larger than the shank of a pin. It is from these two holes that the gas escapes to the tees on which are fast- ened the man- tles. To adjust the mixing of the air and gas the tees should be moved back and forth until the mantles burnthebright- "yw" Vy .. ST. p> : 4 : The sn The gas is blown throug! Ing 1S S€H-€X- small holes into the tube planatory. above the lamps Seer" i Peete ‘an acted ons es Pek a i MN 2) CS A

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May, 1921 ‘gees , ; one : ec RNG — 7 | - : : | Temperature i. Our eEVerydad Y life. : —temperature frequently determines where you : shall live. —temperature always determines what you should eat and wear, how warm or cool the home should be to insure personal comfort and good health. of J the FE [the FF THERMOMETERS \ yy The | . had § ega- tell the temperatures so you may KNOW what to a | do and HOW to live: e a “ee E The 7ycos Health Thermometer shows you the tem- jo E Seca, "& perature of your home so you may dress according fi e ol DoS Neg oa tei ice am “aN r Prevents ‘pee a SG hae Oak to the weather. swig ed Fever unnecessary Orin 4 - as OEY My qn ~ Tk . ) rest ff Thermometer The Tycos Fever Thermometer enables you to keep an on the xing ff Seams See sse watch over your health—to KNOW when you are doctor. was threatened with illness rather than imagine—to make intelligent records for the doctor—to save yourself Worry. E The Zaylor Home Bake Oven Thermometer, Home 23 Candy Maker’s Thermometer, Sugarmeter, Deep _— # Fat Frying Thermometer give you temperatures pipe- that assure uniform cooking in the preparation of wre | food, candy and delicacies under the most favorable Conserves food ites : eee conditions. through preven- TaylorHome Bake The T B oe de . tion of mistakes ; | OvenThermomoter e T'ycos Barometer indicates changes in the weather in cooking. ei Stet from twelve to twenty-four hours in advance so you f 5 can be prepared rather than be taken unawares. ae ip ty . mt ro — FF Every householder should have these 7’ycos Temper- | ature helps. Ask your dealer or write us direct for peo | interesting booklet. : TO MANUFACTURERS ba There is a Tycos Temperature Instrument—indicating, or ee — recording, controlling—for every type of industry and 7 Makes You in- a every process in industry where temperature control is ae dependent -ssential, : oe of the Weather Tycos Barometer atts man.,: Taylor Instrument Companies ROCHESTER NY. Eee There's a 7ycos or Jaylor Thermometer for Every Purpose

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Factory - built, Low-priced. your dealer. oOGAN GRAAGES

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(RESIDENTIAL 16 N. Ashland Blvd. Chicago | Unsurpassed facilities for a com- cation. Distinguished Faculty. Modern and extensive laboratory equipment } arge clinic Gymnasium dormitory ends “— ents’ aid dept. Chicago's op- portur ty for we elf help unlimite i. Enter | quarte ith Yea plete Scientifie Chiropractic edu- } | ty term. 1

A TOGAN GARAGE For Your Car durable construction; fully equipped, ready to use, complete. And you can erect it yourself if you prefer. This model size 10 x 16; $156 plus freight. We deliver your garage to your lot through SEND FOR CATALOG TOGAN-STILES GRAND RAPIDS, MICHIGAN

VASE FORD 'NiQ SPORT CAR Patens Other types down to $3.50. Famous, sure fit, Red-i-Kut Kut 56:40 lite size patterns and simple_ instructions show all details. You can easily convert your ae into this fast, saucy speedst as hun dreds have’

material from hardware store No -_- lo lay up the car al’ with disc al * a terns only $6.40 deliv- ered. Built low, rides)

Keen, Classy Upt to the minute ws mnderfully easy. Or er NOW from this ad We will send “gr Pressed Metal Streaming Rear which makes fine finish. Sez; c coin for prospectus Kuempel ale 205 Engineering Bldg.,

Guttenberg, lowa

MACHINE SHOP WORK guide to the most improved methods of modern shop practice, including the construction and use of im- proved tools and machines, the use of various hand tools, the lathe and lathe tools, and the methods of screw cutting, taper and eccentric turning, etc. 360 pp. 401 illus. Price, postpaid, $2.60 Popular Science Monthly, 225 W. 39th Street, New York

Tooth Brush

Popular Science M onthly Utilize the Sun to Blow a Steam Whistle SOLAe engines have been built by many inventors, but most of these were ex- pensive and complicated, quite beyond reach of the amateur. The illustration shows a solar whistle such that any boy can make, provided hx knows how to solder. The apparatus i: made of a reflector, a boiler, and a whistle First the reflector is built, the wooden frame of which is shown in Fig. 1. It parabolic, not semicircular, curve should b:

In Fig. 1 the construction of the para- bolic mirror is explained; in Fig. 2 the support of the boiler, and in Fig. 3 how to draw a parabola carefully drawn, then cut with a spoke- shave, jackknife, or jigsaw. Figure 2 shows a method of drawing a parabola. A and A, B and B, C and C, etc., should be of equal lengths. To this curve a surface of brightly tinned metal is tacked. The sides of three large coffee-cans have been successfully used for this purpose. A length of heavy wire is fastened to one end of the cross frame, Fig. 3, to hold up the boiler, the glass casing of which is shown in Fig. 5. At this point, the heating ability of the reflector should be tested and its focus or local zone determined. The day must be clear, with a temperature of eighty or

above. Smoked glasses had best be worn cama) ple \GHERMOMETER AIR SPACE FIG.4 FIG.5 Here is shown how the boiler is tested and how it appears when fully equipped with filling-tube and whistle as the glare of the reflector is blinding. In a protected corner the reflector is set up facing the sun. It should be moved so that the rays converge just over the center, adjustment being made by passing a piece of white paper through the local zone. The glass jar is then fixed in the wire frame and a thermometer placed in the jar, Fig. 6. In five or ten minutes it should read at least 230° F. In place of the thermometer a black metal vial filled with water may be placed in the jar. It should boil in two or three minutes. The cylindrical tank or boiler to be placed in the jar has a filling-tube fitted

sms Br

May, with é can. solder eylind de id A st tc € pipe in § be cle cap h better attem tin sl Usel 2 rin either bells these perso @)PUSIA Leen Sary \y owe LO { ay a Se llag mav ealic . =) 15% A Le} ‘ \ () d t 1! : turn ( Sa MN lam

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\y 1d a ry a ji nm In up at PY, ce ar, ld he ith ld be May, 1921 with a secrew-cap cut from a discarded oil- can. This tube and the steam-pipe are soldered to the lid of the jar and hold the cylinder in position. With a coating of dead black enamel the boiler is complete. A steam whistle from a dismantled toy engine is soldered to the steam- pij e, Fig. 5. in general, the glass of the casing should be clear. An olive-jar with a metal screw- cap has served very well. The boiler had better be too small than too large. No attempt should be made to polish the shiny tin surface of the reflector. Useful Wiring Diagrams for the House T is frequently desirable to be able to ring the same bell from a single cell by either of two push-buttons or to ring several bells from. the same battery. Simple as these propositions may sound, to many persons they present quite a puzzle. The RELL BELLU = BATTERY @)PUSIA PUSIA BUTTON BUTTON ‘a S SCLL J BELL PUSH BUTTON PUSH BUTTON ls | l O MUU DRY CELLS PUSI| BUTTON U ° PUSH BUTTON e FRONT BACK POOR DOOR @—+t BELL DRY CELL | reont DRY CELL a dy y200k lates. Door & | ‘ These diagrams illustrate the wiring for single or multiple bells; the second diagram shows the double control of a single lamp accompanying diagrams show the neces- sary wiring and are self explanatory. Another diagram shows how it is possible. to turn on a lamp at one end of a eorridor and turn it off at the other end. As the diagram stands, the lamp is lighted, but it may be turned off from either end and relighted from either end. It makes no ifference in which direction one passes through the corridor, the switches will always work. Passing from S to S, and extinguishing the lamp at the latter point. upon returning it may be relighted by turning switch S, into its original position, ( another person following in the ime direction may always relight the amp.—-F. L. DARROW. m— “Just like 2,000,000 shavers proved this statement before En- ders was ever advertised. wiping your face with »~ atowel ™ SAFETY RAZOR Your Shaving Troubles Simple-Safe-Sanitary Needs no adjusting. instant use. —together in three. Ends Ready for Apart in one second Wr Gnrdlorsr Enpers Sates Company 17 Battery Place, New York ENDERS SELLS FOR $1.00 with six blades of the best quality Swedish-base steel. Packed in black Keratol box, velvet lined. Extra blades, package of 5—35 cents. INCANADA—Razor, $1.50. Blades, 50c. FOR SALE BY BEST DEALERS EVERYWHERE Blades—Hand-stropped, Hand- tested ;

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Popular Science Month : M To Bore Rectangular Hole:

through Metal our amateur worker frequently has 1 3 . cut a square or rectangular hole throug B le: a steel bar, as when making a boring-bar «+ 4 lay fly-cutter with an inserted cutting-to 4 er The common way is to drill a series of ho! 7 I cutting into each other and then chip awa E pe the corners with a cold chisel and finish | th filing. Unless the worker is a skilled mechani — it is difficult to turn out an accurate and ing smooth piece of work, but if the hole is | roughed out as accurately as possible by the | . means described above, but a little under E . size, it may be given a good finish by fore- | ing through a hardened steel block, or FF Ins “drift,” the exact size of the hole, ina vise, — ls if nothing else is at hand. , The drift can be filed up from a piece of tool steel and then hardened and tempered, or made by breaking off the end of a flat or square file and grinding to shape, taking care not to draw the temper while grinding. COAS t la TO CLEAR DRIFT —~ Don't fail to tell your dealer that you Ride a Bicycle _ want that new bicycle equipped with a re Corbin Coaster Brake! That’s the dead-sure way of guaranteeing N th yourself positive brake control as long cn pl as the bicycle itself remains in use. The Corbin Brake is standard J —- th ee: ee , or optional equipment on the BRASS j Sa No jolting or jarring the wheel to pieces following makes of bicycles. Snnpess m when you slow down or stop suddenly— Insist that it be equipped on PACKING slight pressure gradually lessens the yours: speed; pressing just a trifle harder Dayton DRILL AND CHISEL) brings an easy, smooth, complete stand- Snell OUT CORNERS still—vitally important in traffic. National i — How the problem of cutti q or ee ee , . World ow the problem of cutting a rec- ‘e Made by . orbin ~pionec rs in the bast Pcie tangular hole through metal can be ness—twenty years of faithful service Admiral solved is described and illustrated } et behind it. Don't merely ask for the Henderson I m Corbin—make sure you get it. , m a the rear, but never toward the front edges, i Fred St. Onge’s famous booklet, 7 for this would cause the drift to act as a “oT ‘tt Say Adlake id Ca vei The Art of Bicycle Riding, lver Johnson wedge and bind in the hole. a ee Emblem A heavy machinist’s vise will be the most is CORBIN SCREW CORPORATION Pierce convenient means of forcing the drift pl : iii ih eae eal Pope through the roughed-out hole, but if too A nen Hardware Cor} iota Succe eat Cleveland much pressure is required, it indicates that f we panies ye Se Es See an ner an excess of metal is being cut out by the | AC Branches: New York Chicago Philadelphia —and others drift, and to prevent its binding or break- ing, the work should be removed and the & drift forced out backward and the hole LSS a A packing-sheet of brass or copper is | Oh Boy ae This Car placed between the drift and vise jaw, and This nifty little car x = | KEROSENE fateh las in order to allow it to be forced all the way oariven yy Bsoll . lh built 1h odeedth aaa Bt BB ot through the work, the latter is supported ) oy. New 1921 Durable, Powerful, Reliable, Mas- by a saddle on that side. The saddle is y plans, big sive. Built to last; to do ‘hard, OP 4 al ger, better heavy work, Uses Cheapest Fuel. made by drilling or boring out a block 0 Path rated. Lowest Prices. "3 Months Trial. Easy Terms. cast iron to fit the work and then sawing it or build- izes to 22 H- asy to start 0° crankin ° ‘ ili « " j ive ing plans Gaaeten, OB weer Gaemeeane.’ biset oraatiogd Gncine in half and drilling a hole through it togive | ; jlistof parts ever built- Engine book free. A postal brings it. clearance to the drift. Lacking a saddle of | showing how . . . r to build this Iad’s car. mt te Gee Se Ce. this kind, an ordinary V block may b« SYPHER MFG. CO.. 174 Sypher Bidg.. Toledo. Ohio 4

made to serve the purpose by letting the end of the drift through. Then packing : te inserted between work and vise jaw so that ; +} 2/Feet\m ONLY : : | the drift may be forced farther out. A soft = LONG E99 & steel block will also be required back of the t} eT y ENTS = drift to force it all the way through th ACHROMATIC TELESCOPE MADE UPON NEW oo PRINCIPLES. work, unless this was itself made longs

YOU WANT

JUST WHAT

Positively such a good Telescope was never sold for this price before. Eastern Telescopes are ‘ ‘ j awav f made by one of the largest manufacturers of telescopes in America; we control entire oc tion: and the rear portion ground away f 2 measure closed 8 inches and open over 214 feet in 4 sections. They are nicely brass bound, with clearance. d) scientifically ground lenses. Guaranteed by the maker. Every sojourner in the country or at the ee E 5 f ‘end 0) A seaside resorts should certainly secure one of these instruments, and no farmer should be without _ If the drift is properly constructed, th 1D) one, The scenery just now is beautiful. A Telescope will aid you in taking views. Objects are , ‘ . 2 : . a a: re’ brought to view with astonishing clearness. Sent by mail or express, safely packed, prepaid, for hole roughed out nearly to size, and lard~« Ul only 99 cents. Our new Catalogue of Watches, etc., sent with each order. This is a grand offer or other lubricant applied, the resultin and you should not miss it. We warrant each ee just as represented or money refunded. rill ¢ h secure ‘ 4 , Send 99 cents today. To dealers 6 for Four Dollars hole will be as smooth and accurate a : si EASTERN NOVELTY CO., DEPT. 24 172 E. 93d STREET, NEW YORE. could be desired.—H. H. PARKER. 88

Popular Science Monthly fF May

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ges, as a nost irift too that the eak- the hole r is and way rted le is k of ng it give le of y be the ng is that soft f the . the long r fi , the “d-o ting ea May, 1921 How to Save the Cost of Scaffolding Timber Gore time ago the slate roof of my house needed repairing. When I learned that it would cost me twenty dol- lars or more for the scaffold that would enable the roofers to do the work in safety, I tried to find a way to avoid this ex- pense. The pictures show how I made this possible by means of a roof jack, The board, resting in the gutter, pre- vents the ladder from sliding which I improvised and attached to the ladder in the manner shown. I used a board about 2 ft. long, and bored 2 holes in which I put a heavy wire, fastening the ends of the wire to a rung of the ladder. When placed in position on the roof, the board would rest in the gutter and prevent the ladder from sliding down the slanting surface. The ladder would safely support the weight of two average men.—D. L. MERRILL. A Hardwood Chuck for Machining Small Gears OME small cast-iron gears were re- quired to be bored out to a larger diam- eter and faced off, and as no suitable equip- ment was at hand, a hardwood chuck was made up for the purpose that would prove suitable for other small parts besides gears. ; Two hardwood blocks were used, one being permanently bolted to the lathe face- plate, with one edge even with the line of ADJUSTABLE BLOCK WOOD SCREW TO LOCK CARDBOARD SHIM | — FACE a In an emergency this hardwood chuck was used in boring and facing gears FIXED BLOC the lathe centers. Then another was bolted to this by means of two long bolts through the edges of both blocks; card- board shims were put between the blocks before tightening the bolts. Two holes, larger than the bolts to be used, were drilled through the second block and bolts put through it and the faceplate and tightened up. Next, a hole slightly larger than the de- sired bore of the gears was drilled through May, 1921 A Surprise Awaits you in this ten-day test This is to urge that you brush teeth for ten days in a new way. Combat the film. Bring other good effects. The whiter, cleaner, safer teeth will be a delightful surprise. To millions of people this method is bringing a new era in teeth cleaning. It combats film One object is to fight the film— that viscous film you feel. This is the teeth’s great enemy. It dims the teeth and causes most tooth troubles. Film clings to teeth, .gets between the teeth and stays. The ordinary tooth paste does not effectively combat it. So night and day it may do a damage which few people have escaped. It is the film-coat that discolors, not the teeth. Film is the basis of tartar. It holds food substance which fer- ments and forms acid. It holds the acid in contact with the teeth to cause decay. Millions of germs breed in it. They, with tartar, are the chief cause of pyorrhea. Despite the tooth brush, all these troubles have been constantly increasing. New methods now Dental science, after diligent re- search, has found effective film com- batants. Able authorities have amply proved them. Now leading dentists, in PAT OFF Pepsaodent REG US. 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. Europe and America, advise their daily use. The methods are embodied in a den tifrice called Pepsodent. And millions of people have already adopted it. Watch these desired effects Pepsodent combats the film in two effective ways. Then it leaves the teeth so highly polished that film-coats can- not easily adhere. It also brings other effects which modern authorities desire. It multi- plies the salivary flow, as certain foods would do. That is tooth-protecting agent. It multiplies the starch digestant in the saliva, to digest starch which otherwise cling and may form acid. It multiplies the alkalinity of the saliva, to neutralize the cause tooth decay. Nature’s_ great deposits acids which Thus twice a day it brings to users unique tooth protection. Send the coupon for a 10-Day Tube. Note how clean the teeth feel after using. Mark the absence of the vis- cous film. See how teeth whiten as the film-coat disappears. Read in our book the scientific reason for each new effect. Do this now. It is most important, both to you and yours. It may lead to life-long benefits which you cannt afford to miss. Ten-Day Tube Free” THE PEPSODENT COMPANY, Dept. 579, 1104 S. Wabash Ave., Chicago, II. 10-Day Tube of Pepsodent to Mail

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Wouldn’ t he Down He was putting in long hours at unskilled work. His small pay scarcely lasted from week to week. He saw other men promoted. Then he learned the reason. They had special training. He made up his mind to get that kind of train- ing. He sent to Scranton a coupon like the one below. That was his first step upward. The reward was not long com- ing—an increase in salary. Then he was made Foreman. Now he is Superintendent. It just shows what a man with ambition can do! What about you! You don’t have to stay down. You can climb to the position you want in the work you like best. The way to do it is easy—with- out obligating yourself in any way, mark and mail this coupon. — ame TEAR OUT HERE = — = INTERNATIONAL CORRESPONDENCE SCHOOLS BOX 7623-B SCRANTON, PA. Explain, without obligating me, how Ican or the position, or in the subject, before which I mark X. ELEOTRIOAL ENGINEER SALESMANSHIP Electric Lighting and Rys, ADVERTISING Electric Wiring Window Trimmer Telegraph Engineer Show Card and Sign Ptg. Telephone Work Railroad Positions MEOHANIOAL ENGINEER ILLUSTRATING Mechanical Draftsman Cartooning Machine Shop Practice BUSINESS MANAGEMENT Toolmaker Private meeneary Gas Engine Operating B Co 4 CIVIL ENGINEER BOOKKEEPER. Surveying and Mapping MINE FOREMAN or ENGR fits crcroepaphes and Typist STATIONARY ENGINEER TRAFFIG MANAGER Marine Engineer Railway Accountant Ship Draftsman Commercial Law cater boar} GOOD ENGLISH Contractor and Ballder Common Schoo! Sabjects CLjdrehitectural Drafteman CIVIL SERVICE catered y wet Railway Mail Clerk Structural Engineer AUTOMOBILES PLUMBING AND HEATING Mathematics Sheet Metal Worker Navi 0 C)spanish Textile Overseer or Supt. AGRICU LTURE [(Citeacher cell Poultry Raising C)Banking Name Business i-t-20 ABETOSS cee Present Occupation Street and No. City State Canadians may send this coupon to Inte rnational ———- Schools Canadian, Ltd., Montreal, Ca the center line of the blocks to give clear- ance for the boring-tool and then a recess the diameter of the gear and the depth of the required gear face was turned. The second block was removed, also the card- board shims, the gear placed squarely in the recess and the bolts tightened, thus causing the gear to be held accurately for boring and facing. To prevent any possibility of its slipping, a brass wood screw, with its end turned down to fit between two gear teeth, was put through one block. The gears were then bored and faced down even with the sur- face of the wooden chuck.—H. H. PARKER Emergency Thread-Cutting on a Large Pipe THREAD-CUTTING tool as shown can be made from any available block of wood and faced with a sheet of brass or copper at the opposite side from the cutter. The thread-cutter can be borrowed from a die with detachable blades of lesser diameter if the lead is right, otherwise a part of a flat file or small piece of tool steel can be tooth- cut with a triangular file and tempered. When set in the block, it is backed up with a wedge or tapered file for setting it out as the thread is turned. It is advisable to COPPER Wood SECTION With this improvised tool, made of a block of wood and a steel cutter, threads may be cut in large pipes start the thread with a triangular file making two cuts around the part to definitely mark the lead of the thread. When this is done, the thread can be rapidly turned and the size made to con- form to the surrounding part, with the adjusting wedge provided. Similarly, threads that are turned oversize and will not enter can be readily made to size with this method.—G. A. LUERS. Keeping the Wind-Shield Free from Rain ERY few motorists like to drive in the rain, but sometimes it is necessary. At such times, one of the worst things to con- tend with is the rain-blurred wind-shield. A very good way.to overcome this annoy- ance is to carry in one of the car-door pockets a small bottle—about 4 ounces— of a mixture of glycerine and alcohol, about half and half. When it rains, wet a cloth with the solu- tion and rub it down a narrow strip, on the outside of the wind-shield, just wide enough for you to have a good range of sight. Don’t cover the whole shield with it. The water will not remain on the coated glass, which will afford a good enough vision. As soon as the rain stops, look through the uncoated glass beside the coated panel. This saves your wiping off the glass every few minutes.—F. G. Jopp. 90 Popular Science Monthly To Play To Pay EAS (None genuine without this trademark) # ‘True -Tone Saxophone A Buescher True-Tone Saxophone opens the way for you to greatly in- crease your income, opportunities, pepeierity, and pleasure. Easiest of ail wind instruments to play —you can learn toplay thescale §4 in an hour and in a few days {4 ie } be playing popular airs. Prac- a tice is @ pleasure. Tells you when to use Saxophone Book Free Saxophone — singly, in sextettes, or in regular band; how to transpose 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. it perfectly satisfied, pay for it on easy payments 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 AN EASY WAY TO MAKE MONEY -2:::: plod along on a small salary. Be independent. Go in the tire res geiring business. One man says ‘‘I made $60.00 the first —— average $200 to $500 a month. Very little eanital need Jobs plentiful. Every motorist a pos- sible customer. No experience needed. We teach you, SHALER Tire Repair oat nent Wrapped Tread Method by Tire Manufacturers mt. wor’: as the big high priced vulcanizing outfits. A boy can use it. It’s the only vulcanizer that has Automatic Heat Control, and can ‘: undercure or overcure a ‘tire. Requires no watching or regulating. FREE Book **How to Open a Tire Repair Shop.”* It tells how to make big money. Don’t delay. Write quick C. A. SHAL ER co. 2104 Fourth St. Waupun, Wisconsin Free to Writers | WONDERFUL BOOK—read about it si Tells how eas:ly Stories and Plays are c¢ — written, perfected, sold. How many - fa Ww 10 don’t DREAM they can w rite, suddenly spake FH find it out. How the Scenario Ki ngs and th & Story Queens live and work. How bright men © and women, without any special experience, i learn to their own amazement that their sii i plest Ideas may furnish brilliant plots for Plays ha and Stories. How one’s own Imagination may si provide an endless gold-miae of Ideas that bring Happy Success and Handsome Cash Pa Royalties. Ilow new writers get their names into print. How to tell if you ARE a writer. Ps How to develop your ‘‘story fancy,'* weave clever word-pictures and unique, thrilling, realistic plots, How your friends may be your worst judges. How to avoid discouragement and the pitfalls of Failure. How to win! This surprising book is absolutely , free, Nocharge. No obliga- tion. Your copyis waiting for you. Write forit now. if istaddress AUTHORS’ PRESS, Dept. 2, , AUBURN, NEW YORK SAVE 25% to 60") on slightly usec GRAFLEX- KOD. AKS y Cameras and Lenses of every description Equal to new. Save money. Write now for Free Bargain Book and Catalog ating | hundreds o ce oney-saving bargains inslight und ne cameras and supplies. Al ‘foods sold on 10 days’ Free Trial. alone: y vack if not satisfied ou. take no chan dealing with us. We have been in the pho graphic business over 19 years. Write now. CENTRAL CAMERA CO., Dept. 65, 124 S. Wabash Ave., Chicago al mone onal monthly ‘pavinents on Our Easy ry. iM. aren oO coal ia to, “at their boys along. SRY TO RIDER wholesale a that Cpeedlgg or ty aie nt: ws orna, WwW aula, parts an i ires cau equipment, athalfretailprices, neon, NO SROnEY = ay write today for big Ranger Catalog and marvelous prices and terms. Cc e ecial~ Mead ‘ic company see Dollars in Hares We pay $7.00to$1 8.50 and upa pair ind express charges. Big Profits. We furnish guaranteed high grade stock and buy all you raise. Use backyard, barn, cellar. attic. Cons tractand Illustrated Catalog Free. STANDARD FOOD AND FUR Xa 407C Broadway York wh fro wit sep ma ar on ba fla ri

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—— ption ow for talog May, 1921 Transforming an Inner Tube into a Gun-Case to an old inner tube in good condi- tion a serviceable gun-case can be made which will protect the gun and spare parts from possible injury from rain or contact with hard objects. If the barrel of the gun cannot be separated from the stock, the case can be made without difficulty. One end of the inner tube is closed, the other end that extends beyond the stock of the gun is turned over and fast- ened with a strap riveted to the tube to pre- vent it from becoming lost. To carry the case, a shawl strap may be riveted to the tube. If barrel and stock are sep- arable, the tube may be bent in U shape, one part of the U serving for the barrel or barrels, the other for the stock. Both compartments are provided with flaps, closing the ends securely, and the case is carried by means of a shawl strap riveted to one of the legs of the U. INNER TUBE Two types of inner- tube gun-cases Emery-Wheel Dust-Catcher Made of Baking-Tins DUST-CATCHER for use with a 4% jeweler’s or dentist’s emery- and buffing-wheel can be cheaply made of two baking-tins in the manner shown. Buy a shallow cake-tin and a bread-tin of the same width. Invert the O5READ bread-tin, which is the deeper, over the cake-tin and solder these inverted ends together so the LE POPU Te top tin formsan angle as illus- trated. When this is set under the wheel, the dust will be caught by one or the other and deposited in the bottom. For dentists, who use much platinum, gold, and silver, this is an idea that will facilitate the saving of the precious metal dust.—L. B. ROBBINS. EMERY WHEEL CAKE TIN—— The dust of ground metals will be col- lected by the pans Protect Overalls in the Battery Room N the storage-battery repair-shop or charging station, the splashing of the sulphurie acid rapidly eats holes in the workman’s overalls or jumper. Acid will not attack wax or paraffin and for this reason the clothing can be protected with a thin coating of these substances. To apply the protective coating, either heat the wax or paraffin enough to melt, and dip the garment into this, or dissolve the paraffin in gasoline, making a thick solution into which the clothes are im- mersed and afterward allowed to dry Some Styles $14 } fused and uncertain values, you can depend on Florsheim qual- ity. There is an unchanging stand- ard of value in the Florsheim Shoe. The name in every pair Shoes $12 - Oxfords $11 | "THE FLORSHEIM SHOE Co. Manufacturers Chicago The Hampton —Style M-63. Spring booklet “Styles of the Times” on request. thoroughly.—G. A. LUERs. Straddle This Saddle—and Go! | Start your motor, swing on to the comfortable this Cleveland, open the throttle, and you are on the way to where you want to go. The light, sensible, well-bal- anced, quiet and powerful Cleve- land cuts out railroad and trolley saddle of fares, and puts town and country at your command, to go where you like, for work or recreation. The only single chain, direct worm drive motorcycle made. Low center of gravity makes safe and easy to control. It is simple, powerful, durable, economical. Gives better than 75 miles to the gallon of gasoline. Automatic lubrication, 26"x3" tires. The cheapest and most comfortable individual transportation avail- able. Price $275.00 f. o. b. Cleveland See Your Dealer or Write Direct For Catalogue THE CLEVELAND MOTORCYCLE COMPANY CLEVELAND, U. S. A. 91

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It’s aWDC TRIANGLE THE GENUINE BAKELITE Every puff proves that no better ipe can be P Shad Wm. DEMUTH & CO. NEW YORK World’s Largest Makers of Fine Pipes BE YOUR OWN BOSS. MAKE Pp. 4 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 Anderson schools in 34 states, one is near you, Better schooling plus finest equipment makes Anderson tireologists successful. We teach you the famous An- (AePENTERS, 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, learn how. It will help you hold your job—it will get youa better job—it will increase your earning capacity. Write for Catalog B, stating trade DON’T DELAY— it means more money BE A DRAFTSMAN Earn $35-$150 Week Draftsmen are indemand. Books and tools FREE. Write for Catalog G. DO IT TODAY! Columbia Correspondence School Est.1904 Carroll Dept. Drexel Bidg., Phila, Pa. | | | derson method of vulcanizing and the operation of the derson Super-Heated Steam Vulcanizer and Retreader. Takes 5 to 10 days in school and costs $35. If at any time you buy an Anderson Vulcan- izer, we refund your $5 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. Write today. ANDERSON STEAM VULCANIZER CO. 101 Williams Bldg. Indianapolis, Ind. GUARANTEED si TUBE FREE SeP~ 16.000 Tires bought during the recent tire panic and now Sy \, offered te you at greatly reduced prices. This lot includes tires that are rebuilt throughout, slightly used cord and fabric tires and reconstructed tires that were guaranteed by the manufacturers for 5,000 miles. A Standard Make Tube Free with Each Tire Ordered 28x3 ..$5.75 31x4..$9.00 32x414..$10.25 36x44. .$11.90 30x3 ..6.35 32x4.. 9.10 33x4%.. 10.50 33x5 .. 12.00 30x3%.. 7.15 33x4.. 9.50 34x4%.. 10.70 35x5 .. 12.25 $2x33z.. 7.60 34x4.. 9.75 35x4%.. 11.40 37x5 .. 12.75 No Special Discounts to Dealers or Agents Buy your summer tires now. Order today and save ‘ money. State straight side or clincher. Send $2 } deposit with your order and tire will be shipped ; balance C.O. D. Orders will be filled promptly until our limited supply is gone, so order today, before it is too late. Chicago Tire Sales Company 67 Vincennes and 39th St: Chicago | 92 everything.—J. N. PARKER. Popular Science Monthly Vibration Eliminated when Copying Plans T= author had occasion to copy, by means of photography, some two dozen drawings and book illustrations; this work had to be carried out in a large library next to a main street. When the plates were developed, all out- lines were found to be blurred instead of being quite sharp, as in the originals. Some negatives showed this fault more than others, while a few were fairly sharp, quite good enough for the purpose for which they were intended. The drawings were copied again, this time at home, but a special equipment was used to eliminate vibration in camera and easel. A stout board about % in. thick was taken, its upper side planed smooth, and a suitable hole drilled through it to take the camera screw. The board was about 4 ft. long and 1 ft. wide; but this ’ 5 : 5 RUBBER CEILING RUBBER 9 CORD coRD ———4 ciated EASEL | WORK | , BOARD7 If the camera and the object to be copied are mounted on a swinging board, the photographs will be clear depends upon the size of camera employed and must be tried out in every case. In each corner of the board about 1 in. from each side, a hole 1/16 in. in diameter was drilled and through this a strong cord was drawn. This cord should be about 3 ft. long and it must fill the hole entirely; it must be a good fit. A couple of knots were tied at the end of the cord; to the other end a short length of rubber cord was fastened; about 6 in. in length will do. If no rubber cord is handy, the rubber bands used to hold small pack- ages will do excellently. Four hooks are next driven into the ceiling. They should be the same distance apart as the holes in the board; the rubber ends are fixed to the hooks and our repro- duction table is ready for work. The camera can now be placed in posi- tion, and we can copy the most intricate drawing, feeling sure that no vibration will affect the sharpness of our negative, for the rubber bands absorb the bulk of the vibra- tion; the rest only moves camera and easel, but in this case they are moved together and at exactly the same rate, as both rest upon the baseboard.—C. A. OLDROYD. Chewing-Gum Will Stop Leaks in Shoe-Soles TEPPING on second-hand chewing- gum is usually very annoying, but one day I found a piece sticking to a hole that had just come in the sole of my shoe. I didn’t remove the gum and it very effectively sealed the edges of the broken leather and protected the under sole for several days until I was able to have it patched. Apparently there is a use for cexprers MATION ing pli wi tin str co’ ca

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k & 5 pee sa een I a May, 1921 Broaching a Hole without a Broaching=-Machine HE method here illustrated and de- scribed is of special value to the small shop or experimental laboratory equipped with only the ordinary light machinery. Figure 1 almost explains itself. A roached hole may be practically any shape. The hole shown in the box tool \lustrated is square. The first operation is to drill and ream A, say % in. for a -in. quare hole. The two bars to be used for the frame of the hole should be made as Here is a simple method for broaching a hole without a broaching-machine shown in Fig. 2, and planed true at surfaces marked B, and then bolted together. The two should be long enough to allow for bolt- ing and turning a little longer to allow for trimming. After the pieces are turned to a diame- ter slightly larger than the hole in the body pieces (say .002 in.), they may be placed on a milling-machine table. The ends of the pieces that have been left square can be used to line up the pieces and will also prevent them from rocking. This work may also be done on a lathe equipped with a milling attachment. When the grooves are cut, the pieces may be cut off a trifle longer than the body hole, to allow for trimming, as shown in Fig. 3. The snuggest and firmest fit can be ob- tained by shrinking the pieces into position. This is done by heating the body piece, thereby causing the hole to enlarge. This will actually permit a piece larger than the hole itself to be fitted more easily than by a driving fit alone.—F. W. HARTH. Save a Backache When Sowing Seeds \ HEN sowing small seeds in beds, where ordinarily there is much reach- ing, good, even distribution is easily accom- plished by using a tin-can seeder. Any round tin can, so long as it has a tight-fitting cover, will do. Cocoa and _ baking-pow- der cans are the commonest types available. The cover of the can is perforated with many round holes, the size varying with the particular seed to besown. This tin can is attached by the bottom toa strong, stiff stick two to four feet long. In use, the seed is placed in the can, the cover screwed tightly on, and the stick and can held with the perforated cover down. } COVER PERFORATED —~ Avoid a backache by using this seeder W. L. DOUGLAS neil Fri°$8.00 SHOES “2822 “Rect Wotemnsne L0.00 || “Resin Suse? $6.00 FOR MEN AND WOMEN THE STAMPED PRICE IS W. L. DOUGLAS PER- SONAL GUARANTEE THAT THE SHOES ARE ALWAYS WORTH THE PRICE PAID FOR THEM ll They are the best known shoes in the world. Sold in 107 W. L. Douglas stores, direct from the fac- tory to you at only one profit, which guarantees to you the best shoes that can be produced, at the lowest possible cost. W.L. Douglas name and the retail price are stamped on the bottom of all ij shoes before they leave the factory, which is your protection against \, unreasonable profits. YOU C CAN ALWAYS SAVE MONEY BY WEARING W. L.DDOUGLAS SHOES SOLD DIRECT FROM FACTORY TO YOU AT ONE PROFIT W.L.Douglas shoes are absolutely the host shoe values for the money in this country. They are made of the best and finest leathers that money can buy. They combine quality, style, workmanship and wearing qual- ities equal to other makes selling at higher prices. They are the leaders in the fashion centers of America. The prices are the same everywhere; they cost no more in San Francisco than they do in New York. AFFIRM: THAT W.L.DOUGLAS SHOES~.GIVE ME THE BEST . VALUES. FOR MY MONEY IN STYLE COMFORT an? SERVICE W. L. Douglas shoes are made by the highest paid, skilled shoemakers, under the direction and supervision of experienced men, all working with an honest deter- mination to make the best shoes for the price that money can buy. Cc A UT l O N eee oan berine ba and price is plainly stamped on the sole. Be care- ful tosee that it has not been ” tah or mutilated Ho Ga y, W. L. Douglas Shoe Co., 7124 Spark St., Brockton, Mass. cece ccc oateh Big AC, .. J NJOY the thrill and excitement yee bait-casting ans sling W.L.Douglas shoes are for sale by over 9000 shoe dealers besides our own stores. If your local dealer cannot supply you, take no other make, Order direct from the factory, Send for booklet telling how to order shoes by mail, postage free, Needle Points Instead of Tacks and Nails You can hang and rehang hundreds F of pictures, drawings and other light weight things to the walls of your room, without injuring plaster, wood- work or paper, by using es, by casting for em with the South Be ad Reel which entirely eli iminate Moore Push-Pins | f back- lashes, snarls and tang} Our bo« “The Days ot Real Sport,” tells tried and Glass Heads, Steel Points Suggest a use and we'll send SAMPLES FREE Sold by Hardware, Stationery, per | Drug and Photo supply stores 1 Cc kt everywhere pat. MOORE PUSH-PIN CO. 11-5 Berkley St., Philadelphia | ALTE TET ELE LE EGS IEEE BI TEAL along in the reflections of the shore. An occasional dip of the blade keeps you moving. For an “Old Town Canoe” floats as lightly as shadow. It responds instantly to the slightest pressure of the paddle. And built into every “Old Town” is a strength that makes it last for years. Write for cata- log. 38,000 cances in stock. $67 uv from proven casting methods. Shows complet« ) f South Bend Tackle line of Reels and Baits. A postal brings it FREE. 0; x SOUTH BEND BAIT CO. // yf ~ 14509 High St. South Bend, Ind. }/ (16) ey : —__— ; a Brissy = on 99 OLD TOWN CANOE CO. 1195 Main Street Old Town, Maine, U.S. A. dealer or factory.

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” —t (= — _ SS = =a x Finish This Picture Fill in the missing lines. See how close you come to the orig- inal drawing. The above pic- ture was drawn by Student Wynn Holcomb. We have a great number of students and graduates whose work appears in magazines and newspapers all over the country. Can You Draw? If you like to draw write for our book. Read about our new method Home Study Course in cartooning, illustrating, designing. Learn at home, by mail, in spare time. Become an Artist Illustrators, Cartoonists, Commer- cial Artists make big money. You can earn $25 to $100 a week and more. Learn under personal direc- tion of Will H. Chandlee, famous newspaper, magazine, advertising artist of 30 years’ successful ex- perience. Book and Outfit Free Complete outfit free to new stu- dents. Write for handsome book, “How to Become an Artist.”” Tells what Course includes, shows many drawings made by Director Chandlee and many students. Write Postal NOW Don’t miss our book. Even if you have no previous knowledge of drawing, our Course will enable you to become a successful car- toonist or illustrator. Many students earn money while they are learning. If you are ambitious to get ahead, to earn more money, write for our free book and special offer now. You can do as well as our other successful students! Write now for free book, ‘‘How to Become an Artist.” Mail letter or postal. Washington School of Art, Inc. Room 1618 Marden Bldg., Washington, D. C.

To Make an Umbrella Drain-Stand ‘THE picture shows a useful article that a boy can make out of material offered by a discarded wooden bedstead or other old piece of furniture. A study of the per- spective view will make the joining and construction clear and furnish necessary dimensions. First mark out and saw the sides. If you wish to make the three-cornered hole in the center of each, you must bore three 14-in. holes and saw the intervening part with a coping-saw. A serviceable saw may be purchased for twenty-five cents. Figure 4 shows how each end piece is mortised to the corner uprights. This joint is glued. Figure 2 shows how the top cross piece and uprights are fitted together. It is a very strong and neat joint, but requires considera- ble patience to get an accurate fit. The half cuts are made with a back-saw and the wide wood chisel. The baseboard fits between the front and back pieces. Figure 3 is an en- larged view of this ar The finished stand joint. is ornamental and Fancy wooden __ useful pegs or large metai hooks may be used as rests for the umbrel- las. Glue is used at all joints. I think liquid glue is the handiest for amateurs to use. In assembling this drainer, the sides and corner uprights are first put together, the top and bottom cross-pieces and the Mine FIG.4

Popular Science Monthl); = eo a. MakeYourBike aMotorcycle 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 Motor Attachment. No third wheel! Fits any men’s bicycle of any make or size. Chain drive model can be attached in less thanan hour. A boy can putit on. No special tools or knowledge necessary. SHAWiict..: Thousands in use. A light weight 24 H-P motor of wonderful efficiency. Simple to attach. Everything furnished complete, Every owner enthusiastic. All materials are guaranteed, Get one NOW. FREE 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.1465 _. Galesburg, Kansag “DON’T SHOUT” “Thear you. Ican hear now as wellasanybody. ‘How?’ With THE MORLEY PHONE. I'vea pairin my ears now, but they are invisible. I would not know I had them in, myself, only that I hear all right.’’ The Morley Phone for the DEAF is to the ears what glasses are to the eyes. Invisible, comfortable, weightless and harmless. Anyone can adjust it. Over one hundred thousand eold. Write for booklet and testimonials.

THE MORLEY CO., Dopt. 797, 26 South 15th Street, Philadelphia

KENNEBEC CANOES Please send today for your copy of ournew illustrated book showing the best models of canvas covered canoes made, including SPONSON, the Unsinkable Canoe sailing, and war canoes for clubs and summer camps ; row boats and all boating accessories. me) 4m BOAT AND CANOE CoO. 9 R.R. Square, Waterville, Maine. “SAFEST TO USE”

a [4] A | ie) ° 12} |] | aL "ie eee we | 22 | § | 2 Fr | a) oO 5” coe ‘ r % * | = zobrssphssoogyec | ’ i

on 7" FIG.2 | F An amateur carpenter will have no dif- ficulty in making this piece of furniture middle upright come next, and lastly the bottom face piece and floor. A metal pan should be used to catch the drip. Holes are bored for the wooden pins, which are }4 in. in diameter and 4 in. long, and they are also glued in place. The floor is screwed from the under side to the ends. The finishing is a matter of choice. For new, hard wood like oak you will need in the order named, a thin coat of stain, then wood filler, then stain, then either varnish or wax. If used on aside or rear porch, two coats of green wagon paint would be appro-

priate.—H. ADLON. 94

LEARN AUTOS AND TRACTORS Wonderful opportunities constant- ly offered trained men; we train you thoroughly tostart your own business or make good money as motor expert, driver, shop fore man, etc. 5000 ae ore making good. Catalog Free. Cleveland Automobile School, 1821 E. 24th St. » Cleveland, Obie. AGENTS We need special agents to travel A\ by Automobile introauciug our great line of Nationally-advertised Pure Food Products, Soaps and Household Necessities. Here is an opportunity to earn $6 to $12 a day, all or spare time GW and obtain an Automobile FREE besides, Write at once for full particulars. Address AMERICAN PRODUOTS CO. 2977 American Bldg., Cincinnati, 0. a Build This Phonograph Yourself TREMENDOUS SAVING IN COST Easy, fascinating work, with our SIMPLIFIED PLANS. We furnish blue rints, diagrams, motor, cabinet. pieces ready-built es etc. You don’t need to be a cabinet-make: A few hours yrtgp oe and you will have . fine in- strument at e-quarter ay Ba ular retau price, AGENTS MAKE MONE ing and selling ‘hese instruments. wee enday for full details and our FREE OFFER. A ddress:— —— —— SUPPLY CO. 8 Springer Building

May, 1

313 So. eaten St. CHICAGO, ILL.

Panular Seience Monthly

Profi ry*HE i be % valve fi or iron h ndy, D ely. feet of slip OV sm ill « pump. By ¢ ment c pipe is of the point 2 then fi and a top of has bh valve above betwe end < andar 2 in. | The set or bench desire lon ¢ pared ing t tight, ing a each upper! with ; lengt dered rubbe bicy¢ hole solde Te and | forge has esca] betw esca) valv been oper the ; are plae side B disk the top cin¢ the is b Gi H gus ens me en pe CO) an th

Page 75

May, 1921 Profit and Pleasure in This Homemade Forge r = material required for this forge will be an old flower-pot, a gallon can, a valve from an old oil-stove, and some brass oriron tubing. If there is an old oil-stove handy, the pipe found on it will serve nicely. Besides this, you will need a few fect of rubber tubing large enough to slip over the pipe, two strips of tin, a small quantity of cement, and a bicycle pump. By observing the drawing, the arrange- ment can be clearly seen. A length of the pipe is run through the hole in the bottom of the pot, the upper end extending to a point 2 or 3 in. below the top. The pot is then filled with concrete mixed rather thin, and a small basin hollowed out about the top of the pipe, asshown. After the cement has become thoroughly hardened, the valve mentioned above is screwed between the lower end of the pipe and another length 2 in. long. The pot may be set on top of the bench or any place desired. The gal- lon ean is. pre- pared by solder- ing the cover on tight, and punch- ing a hole through each end. The upper hole is fitted with another short length of pipe sol- dered in tight, and the lower end of the rubber tubing fitted over it. An old bicyele-tire valve is inserted through the hole in the bottom of the can and also soldered tight. This can serves as an air-pressure tank and holds a supply of air for use with the forge. The tire valve prevents the air that has been pumped into the tank from escaping in that direction, and the valve between the forge and the tank allows it to escape through that passage only when the valve is open. After a supply of air has been pumped into the tank, the valve is opened to the proper point, thus regulating the air blast to the furnace. The tin strips are to support the tank and hold it in place. A convenient place will be at the side of one of the legs of the bench. Before starting a fire in the forge, a small disk of wire screen should be cut to fit into the bottom of the concrete cup, over the top of the inlet pipe, to prevent ashes and cinders from dropping into the valve. Then the forge is ready for use. For fuel, charcoal is by far the best.—DALE R. VAN Horn. SCREEN

FLOWER POT CONCRETE

\ 1) 2 eR i Hi mm OLD TIRE VALVE ih a= TO BICYCLE a’ PUMP This forge will be of practical service RUBBER TUBING

GALLON CAN TIN STRIP Guard Against Deterioration by Rust AVE you ever noticed how quickly rust eats a hole through the mud- guards, hood, or body of your car after the enamel has been worn or knocked off, ex- posing the metal to the action of the ele- ments? It pays to keep a little can of automobile enamel of the color of the body finish ready to touch up any bare spot as soon as it ap- pears. It may not look just as well as a complete new coat, but it will prevent rust and at the same time look much better than the rusty spot.

Wireless Operators Wanted At Once—-For Merchant Marine, Commercial Land Radio Service, Radio Supply Factories, U. S. Navy, Government Service and Aerial Mail. National Radio Institute experts will teach you Wireless at our home by mail, through fascinating course of copyrighted essons and our famous automatic Natrometer SALARIES UP TO $3,5000 A YEAR Exceptional opportunity for ambitious men for promotion to the higher branches of Radio. Our graduates are qualified as Senior Operators, and besides Room and Board, receive $125 a month to start, which altogether means more than $200. Positions to which they can promote themselves are as follows: Supercargo and Wireless Operator 175 a month; Radio Mechanic—$1,500 to $2,000 a year; Radio Aid—$6.00 to $8.00 per day; Radio Inspector—$1,500 to $3,000 a year; Radio Engineer—$6,000 and more a year; Radio Draftsman—$7.00 to $10.00 a day. You can learn wireless the National Radio Institute way, quickly and easily, by mail right in your own home, in your spare time. No previous experience or training Is necessary. With our help you can quickly qualify for first grade govern- ment license and a fine position U. S. DEPARTMENT OF COMMERCE RECOGNIZES N. R. I. and allows its graduates 5 to 10 points credit when taking the examination for First Grade Government License. This school heads the printed list of reputable Wireless Schools recommended by the U. S. Shipping Board TRAVEL WITHOUT EXPENSE If you are eager to travel, anxious to visit foreign countries, and increase your knowledge of world affairs, Wireless offers the chance of a life time On shipboard you are rated as an officer You need not travel unless you wish, but may secure a position at one of the many ever increasing land radio offices. NEW AUTOMATIC WIRELESS INSTRUMENT FREE In addition to all necessary text books and other equipment with which we supply you, we furnish FREE to every student our marvelous new automatic Natrometer, which transmits Wireless messages in 600 different combinations, and can be regulated to operate at any speed from 1 to 30 words a minute. it is complete with phones, etc., and is sent you in a neat carrying cas« This instrument is operated entirely without the use of aerials and is used exclusively by the National Radio Institute to teach Wireless at home in the scientific way

Natrometer becomes your personal property upon completion of our course SEND FOR FREE BOOK Write to-day forF REE BOOK “Wireless the Opportunity of To-Day,"’ containinginteresting and valuable information. NATIONAL RADIO INSTITUTE Dept. 568 Washington, D. C.

Print Your Own cards, circulars, labels, tags, menus book, paper. Press $12. Larger $35. Job Press $14) up. CUTS EXPENSEIN HALF. Bam 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 PPESS CO., D-33, Meriden, Conn.

OteExe 2.65 3 EF fe):

e . “Success in Music b4 99 How To Win It Has... Lt Sousa, Pryor ~~ and eight other world-famous musi- cians tell you secrets of their B success; how to discover and cultivate Z your musical ‘“‘bump”’; double your income and pl: asure playing in band or orchestra. FREE TRIAL Any Instrument Conn instruments are used by world-famous artists. Known every- where as easiest of allto play. Try any instrument FREE. No _ obligation; easy payments when you buy. Send coupon for free book and details of free trial plan.

—< 1,

532 Conn Bldg. Elkhart Ind. Agencies in all large cities is & Fe FF FF FG C. G. Conn, Ltd. §32Conn Bldg., Elkhart, Indiana. Gentlemen:—Please send me ‘‘Success in Music’? and details of your free trial plan, (Mention instrument.) ee Street or Rural Rouse City, County— uenen Sumie Instrument ———

\ E-PRACTY MEN SiaMAKE MONEY! Hundreds Have Found Greater income and Prosperity Through This New Profession, The Hovey System of Tire-Practy is the surest, quickest and easiest way to learn the tire repairing business. This Complete and Easy -to- follow Training System has standardized the tire repairing practices of the world. It has been recognized and recommended by the majority of the coun try’s biggest tire companies. It Goes Right to Your Home The Hovey System brings to you a knowledg of the best practices for effective and profitable tire repairing. It goes right to your home Simple charts and clear diagrams make every step of the way to a profitable business easy and pleasant to follow. It shows you how to repair all makes of cord and fabric casings, tubes, pneumatic truck tires, bicycle tires and motor- cycle tires; it gives you business-building plans and systems.

It makes you a profit-making link in the chain of Hovey Tire-Practy stations. The Hovey System is World-wide in Operation. Write today for plan booklet Dept. 3 THE HOVEY EXTENSION SCHOOL Akron, Ohio, U. S. A.

Page 76

Your Choice 75c a Wee With every set is included — FREE a Consulting Membership which gives you the privilege of submit- ting your perplexing problems to a corps of experts for an entire year. This Consulting Membership regu- larly sells for $12.00. No matter what your occupation, one of the home study sets listed below will quickly fit you for a better job and bigger pay. Any set you select will be sent for seven days’ examina- tion, and if you decide to buy you may pay the rock- bottom price at the rate of only 75c a week. But you must act now to get the consulting membership along with the set free. These books are the work of recognized authorities. They are written in plain, easily understood language, by recognized authorities, and contain hundreds of photographs, diagrams, tables, etc., that make diffi- cult points as simple as A-B-C. Handsomely and durably bound in genuine American Morocco and stamped in gold. Pay-Raising Books At Greatly Reduced Prices Accountancy and Business Management, 7 vol., 2700 pages, 1000 pictures. Was $52 50... ; . Now $29.80 Carpentry and Contracting, 5 volumes 2138 pages, 1000 pictures. Was $37.50. Now 24.80 Civil Engineering, 9 volumes, 3900 pages, 3000 pictures. Was $67.50 .........1 low 39.80 Electrical Engineering, 8 volumes, 4100 pages, 3300 pictures. Was $60.00 ...Now 34.80 Automobile Engineering, 6 volumes, 2600 pages, 2000 pictures Was $45.00....Now 2480 Machine Shop Practice, 6 volumes, 2300 pages, 2500 pictures. Was $45.00...Now 24.80 Steam and Gas Engineering, 7 volumes, 3300 pages, 2500 pictures Was $52.50, Now. PRES ate co nooiem ie arse . 29.80 Law and Practice (with reading course), 12 volumes, 6000 pages. illustrated Was Me eee eis Le Ue nc we Sige .Now 4980 et Prevention and Insurance, 4 vols., 1500 pages, 600 pictures. Was $30.00 Now 19 80 Telephony and Telegraphy, 4 volumes, 1728 pages, 2000 pictures. Was $30.00. Now 19 80 Sanitation, Heating and Ventilating, 4 volumes, 1454 pages 1400 pictures. Was BID 6 sce e-0 eet ee .Now 18 80 ——e 4 volumes, 1578 pages 1000 pic- tures, blue-prints, etc. Ww as $30.00...Now 1980 Send No Money Shipped for 7 Days’ aie Yes. we'll gladly ship any set right to your home or office upon your simple request Pay only shipping charges when the books arrive Don't send a penny until after you have used them seven days, then re- mit only $2.80 or return them at our expense. Pay balance atthe rate of $3 00 a month—75c a week. Act now—while these splendid books are being offered at 20% to 50% less than regular prices. This offer is open to every person within the boundaries of the U.S.and Canada Grasp your opportunity— fillin and mail the coupon NOW! American Technical Society, Dept. X-205, Chicago | American Technical Socty, Dept.X-205, Chicago, U.S.A. | American Technical Society, Dept.X-205, Chicago, U. S. | Please send me set of.. | for 7 DAYS' examination, shipping charges collect | I will examine the books thoroughly and if satisfied will send $2.80 within 7 days and $3 each — until | I have paid the special price of decide not to keep the books I will notify you - af. and hold them subject to your order Title not to pass to | me until the set is fully paid for REFERENCE How to Protect Stopcocks on a Gas-Stove MALL children who have access to the kitchen during cooking operations are liable to cause accidents by playing around the gas-stove and mischievously or acci- dentally turning some of the stopcocks on or off. The writer, aware of the danger, constructed a shield, shown in the accom- panying illustration, to protect the stop- cocks of the gas-stove from the busy little fingers of his children. The shield is made of galvanized iron with rims of the same material soldered safety de- mands that the stopcocks of the gas- stove be protected Where there are children, over the sharp edges. It is attached to the feed-pipe of the stove by 3 ring hinges of heavy wire. At one end is a wire hook by which the shield can be fastened in position. The picture clearly illustrates how the curved tin cover fits over the handles of the stopeocks and makes it practically impos- sible to reach them without swinging back the shield.—LEROY C. SCHENCK. Preserve Your Papers with This File N almost any desk will be found at least one of the ordinary files on which papers and memorandums are stuck for future reference. In many cases the paper that is wanted will be found at the bottom, making it necessary to remove all the papers to get to the one wanted. Quite often the papers are torn or the point of the file passed through an important figure or word, making it almost illegible. If the file shown in the illustration is used, it can be attached to any desk with- out defacing it in the least, and it eliminates the disadvantages named above. A piece of spring wire is bent into the shape shown. The large loop gives the neces- sary spring to the file. The filefastens to the under side of the desk ledge by means of a wood screw passing through a small loop in the end of the file and screwing into the ledge. The paper-finger also has a loop in the end and is smoothed up to prevent any sharp points from tearing the papers. In use, the paper-holder is raised slightly and the paper shoved under. The tension of the spring will press the arm down, A clip like this may safeguard valuable papers clamping the papers tightly to the desk. 96 Popular Science Monthly ' on) i " y A al Pg a . From factory to you — FRE Easiest riding, most comfort- able wheel built. We’ ilship to you on approval. You'll surely want it when you see the 18 exclusive features of the wonderful 1921 model electrically equipped BIACK BEAUTY There’s a large variety of models to choose from. Pick the one you like best. We'll ship it to you express prepaid on approval. A small deposit and a DOLLAR A WEEK makes you the owner. Our direct factory * price saves you money. You get a liberal 5-year guarantee and 6 months’ accident policy with every wheel. HAVERFORD CYCLE COMPANY Established 25 years remarkably low ept. 385 Philadelphia, Pa. prices. Send for it Be @ Black Beauty Owner Agent —NOW Big new catalog in colors—FREE Something every boy needs. It shows everything a bicy- cle rider wants at BIGGER PAY-SURE WORK We can help you get both—quickly—just as we have done for hundreds of others. We take only a brief time to fit you for a Government position. Short hours. Good pay. No lay-offs. Regular promotions. An- nual vacations. New pension law creates many vacancies throughout the country this year. Position guaranteed, or your money back. Write Today for Big Free Book. Tells all about Government positions you can fill—and how togetone. Ask for Book HO WASHINGTON CIVIL SERVICE SCHOOL 4095 Marden Buildin Washington, D. . GOODYEAR TREAD Tires Cheap! Biggest Tire Bargains Ever Offered 6000 Mile Guarantee Size Tires Tubes 30x3 $13.50 $2.25 30x3% 15.50 2.50 32x3% 17.00 2.65 31xt 18.12 2.75 32x4 19.96 2.85 33x4 20.70 2.95 34x4 21.04 3.10 34.4% 26.30 4.50 35x4% 27.26 4.75 36:4% 27.60 5.00 35x5 31.30 5.25 37x5 32.70 5.50 ORDER NOW. Discount of 5% when fu! amount accompanies order. CROW TIRE SUPPLY 203 W. 58th St. , New York City, N.Y. $$ rx»S»)) YoucanlearnFox-Trot,One-Step, Two- Step, Waltz and latest ‘‘up-to-the-minute”’ so- ciety dances in your own home by the wonderful Peak System of Mail Instruction. New Diagram Method. Easily learned; no music needed; thousands taught successfully; success absolutely guaranteed. Write for Speciat Terms, Send today for FREE we and surprisingly low offer. WILL GHANE LER PEAK, M.B. o137 Broadway, Chicago, tt, The most wonderful and only set !of keys ot its kind Chey open and test thousands of different locks. They have satisfied thousands of purchasers. and are used and recommended bv locksmiths janitors detectives and They are unequaled as a useful, convenient Send $1 U0 for set and novel key chain other great key users and household article MASTER KEY CO. milwaukee, wis. IN POP-CORN CRISPET TES BiG. ne hOD eI Se Meisner, $250 in one day Shook, $311 one day Se opt. 1920. Erwins boy (going to school) makes $35 every Sat afternoon. Erwin says $6 yields $28. No theory! Noguesswork! Actual proven record of successes Send for booklet, Long Eakins Co., 547 B. ee ae ana Ohio Write the Words for a Song We write music and guarantee to secure publication by a New York Music Publisher Our Lyric Editor and Chief Composer is a song-writer of national reputation and has written many big song-hits Submit poems on any subject. Weex amine them free. BROADWAY STUDIOS 249 Fitzgerald Building Broadway at Times Square New York, N. Y. is us othe the for t ib held the end whi espe a som 4 breé gal T witl into sma vial int rese BASE BOAT BRAS HEL ARE CLI Th ict ind att one sire

Page 77

sts Ri ae saree

May, 1921 Making an Air Thermometer for Experimental Use CAPILLARY tube of not over 1 mil. bore, or a regular thermometer tube, is used and the bulb blown at one end, the other end being left open. The length of the tube can be 6 to 8 in., allowing some for the bulb. To blow the bulb, the end of the tube is held over a gas flame until red hot. Then the pliable glass is pushed up to thicken the end and form a mass of material from which to form the bulb. Blowing this, especially to a large diameter, requires some practice and skill, but should the bulb break, the glass can be melted together again and the attempt repeated. The tube is mounted on a wooden board with the bulb at the top, the end extending into a small glass reservoir made from a small-diameter test-tube or from a medicine vial with the top cut off. Grooves are cut in the wood block for the bulb, tube, and reservoir; these are held in place by brass

BASE BOARD BRASS SHIELD BRASS CLIP TUBE

BRASS "LIP

GLASS RESERVOIR | 2 | BRASS /\ {2 D

CAPILLARY TUBE WITH BULB BLOWN ON END

l=

This air thermometer is not an actual temperature recorder, but it will show slight variations as well as a real ther- mometer clips, and as the bulb is exceedingly fragile, it is a good plan to protect it with a brass shield cut to shape as shown. Mercury, while it is the most permanent, would be too heavy for use in an air ther- mometer of this kind; alcohol, dyed red, is suitable, though water would answer the purpose. To fill the tube, the bulb is held in the hand for but a few seconds to warm it slightly and expel some of the air. Then if the end of the capillary tube is quickly in- serted into the liquid in the reservoir, some of it will be drawn up the tube as the air cools and contracts in the bulb. Should the liquid fill the tube and run up into the bulb, it must all be driven out by warming the bulb again and the operation repeated until, under normal conditions, the colored liquid stands about two thirds up the tube. A little experience of this sort will quickly lemonstrate that the larger the bulb and the smaller the bore of the tube, and the ighter the liquid used, the more sensitive will be the action of the thermometer. The reservoir being open to the air, evaporation will occur to some extent and the liquid must occasionally be renewed. This instrument, not being intended for an actual temperature recorder, but only to indicate small changes, no scale is shown attached to the board, though an arbitrary one could be very easily used if so de- sired.—H. H. PARKER.

and Tractor Business Make a good business deal! Get the knowhow of Auto Mechanics in 6 to 8 weeks at this greatschool, Top salary positions wait- ing for your Rahe Trained Skill. The 8 million cars, Trucks, Tractors, etc., must be kept going. Their owners lack the knowhow on repairs. They will pay you big money for your Rahe Training as an expert Auto Mechanic. Get a High-Pay Joh Quick! My advice to any man 16 — i. << years and up is to get into the Auto Repair Business right now! Pays highest and needs most men. Most other trades are overcrowded and are cutting down wages. Rahe 2 School | = | No Special Schooling Needed —Yo)ean —— : : = easily here. 4 You train your hands by oe actual trouble shooting of 4 all kinds on real autos of all makes and models. Don't say you can't—that you are not mechanically in- clined Nearly 40,000 men are Rahe Graduates. Few had any Special Bent for mechanics. Yet Rahe trained men hold high-pay jobs and are in business for them- selvesin every state. You will make good! Start now! Catalog Free? Get my fine 68-page Free Catalog Shows preferred opportunitiesopen to you and proofs

School of graduates success. All Free! Write today! in Cincine ‘ Address School Nearest You nati brings “@e HENRY J. RAGE Dept. 2883 Rahe Training *% Kansas City. Mo.

Cincinnati, Ohio nearer to men in East and South. a Saves railroad fare.

° New Big No. 15-225 pp. e 4 6©Wireless Catalog CATALOG NONE ; - Wireless catalog mailed for 12¢ The Wilbam B. Duck Co in stamps or coin. Any wireless ake $10 Lo $20 dally l Make Show Cards, Signs, Ad- epiaheyy Sars . . z vertising Posters and Glass Signs. Big demand! Inter- — amate ur will te ly ou It 1s the one esting, profitable profession. Easy to learn in few weeks ANE TCL catalogue to have. As an ency by unique novel method; something new! Our wonder- clopedia of information it is in- ful 50-lesson course includes individual instruction by valuable. Thelargest and most correspondence from expert artists; total cost only $15 elaborate radio catalog pub- Every student given $15 assortment of finest ‘Mill . , erine’’ c rs é shes— k LE! lished. Values that cannot be 2 cre one eee ree duplicated elsewhere. SEND NO MONEY receive complet 1 ree ¢ v THE WILLIAM B. DUCK COMPANY and $1 weekly for 12 weeks. Success guaranteed or ‘mone y refund 224-228 Superior St TOLEDO OHIO ed. Earn enough first week to pay for course Send TODAY Empire AB Institute, 2050 Amsterdam Ave., New York, N. Y incertae maa | Sy! | ol eS E T i l you may have any instrument with complete musical outfit. tor a week’s free trial at home. No obliga- tion. Return it at our expense after trial if you wish. Outfit includes velvet lined case, self instructor, music and all accessories at factory cost. Atremendous saving. Convenient Monthly Payments A few cents a day will pay for instrament and outfit if you decide to keep it. Wurlitzer instruments are known aij over the world for artistic quality Send Coupon for Beautiful New Catalog Every {instrument known fllustrated with price, easy terms and free trial blank. Catalog absolutely free. No obligation. Send this coupon now. The Rudolph Wurlitzer Co., Dept. 1785 | 117 E. 4thSt.. Cincinnati_O —329$.Wabasb Ave. Chicago | 120 W. 42nd St.. New York, N. Y. Send me your new catalog {illustrated in color with fail te- } talis of Worlitzer Complete Outfite and free trial and casy j payment offer.

Registered __ i DNR cececessesnnntanccnscencnsnnsssnsnasconccnsens

; 29 : Address sie A 3 ra : OE Srpesat MAKING H ee - = colar * Shae , ved Wurlitser Co. | (State instrument you are epecially interested in.) 97

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Electricity Learn at Home There is a wonderful opportunity right now for young men who like electricity. If you are ambitious and will train yourself in spare time you can step into a good position and get experience that will give you a real start toward success in life. Good salaries are offered with rapid promotion. For 29 years the International Correspondence Schools have been training young men for success in electricity and over 200 other sub- jects. They will help you prepare right at home for a position in the line of electrical work you like best —or in any other work that appeals to you. Thousands of men, through I. C. S. training, have stepped into fine jobs, but never were oppor- tunities so great as now. Let the I. C.S. help you. Choose the work you like best in the coupon below, then mark and mail it today. This doesn’t obligate you in the least, and it will bring you information that may start you on a successful career. ‘This is your chance. Don’t let it slip by. Mark and mail this coupon mow, [ ae = i —=—=—< <<a oa ” TEAR OUT HERE cme eee wee = oe INTERNATIONAL CORRESPONDENCE SCHOOLS BOX 7624-B SCRANTON, PA. Explain, without obligating me, how I can Seepeer the position, or in the subject, before which I mark X. ELECTRICAL ENGINEER SALESMANSHIP Electric Lighting and Kys. ADVERTISING Electric Wiring Window Trimmer Telegraph Engineer Show Card and Sign Ptg. Telephone Work (JRailroad Positions MEOHANIOAL ENGINEER ILLUSTRATING Mechanical Draftsman Cartooning Machine Shop Practice BUSINESS MANAGEMENT {ay ned Operating ie Semuiary a CIVIL ENGINEER Sot epmeepondent Surveying and Mapping MINE FOREMAN or ENGR a STATIONARY ENGINEER TRAFFIC MANAGER Marine Engineer Railway Accountant Ship Draftsman Commercial Law eee ete blanc GOOD ENGLISH ontractor and Bullder Common School Subjects Architectural Draftaman CIVIL SERVICE Concrete Builder Structural Engincer Railway Mail Clerk

PLUMBING AND HEATING ce ence Sheet Metal Worker athematics " Textile Overseer or Supt. Navigation $ panish CHEMIST AGRICULTURE Teacher Pharmacy Poultry Raising §|_)Banking Name Present Business Int-2t Occupation _Address Street and No. = City State

Canadians may send this coupon to International Correspondence Schools Canadian, Ltd,, Montreal, Canada

Another Way to Get Fresh Air ESIRING to use a one-time parlor as a sleeping-room, it became necessary to obtain more adequate ventilation, es- pecially for the summer season, there being but one double-sash window and one large single-sash window that could not be opened. The owner proceeded to take the sash out, hinge it to the outer window-frame and arrange a rope and pulley to lift the

By putting the single-sash window on hinges as here shown, it can be raised to any angle for ventilating purposes window out to any desired angle, or clear to the porch ceiling. Three 3-in. butt hinges, one screw- pulley, one sash-pull, about 10 ft. of window-cord and an awning line-cleat were the necessary materials.—R. A. FRANKLIN. To Keep Insects from Your Food-Basket NTS and bugs have an annoying way of getting into the lunch-basket dur- ing picnics. Here is a plan by means of which the food may be kept safe from attack. Get a piece of stout wire about 18 in. long. Then secure a can lid, or the lower part of a can, and bore a hole in the center of the bottom. Pass the wire \4 | through this hole SA] ; and solder at iI 2 \\ about its middle. Bend each end of the wire in the form of a hook. One of the hooks is attached to the branch of a tree and the other supports the bas- ket. Keep the ¢ — tin filled with f water, and there is a barrier across which no _ insects can pass to reach Insects crawling down thelunch-basket. the wire are stopped by — S. LEONARD

Popular Science Monthly bat eS xX ALiznite ¥ .Is Yours w % for the F 4% Asking No.

Keep it 10 Days Free Wear a LIZNITE GEM RING and . the envy of Let yous, friends. See if you can tell it from a high Driced § piemond, ae ame, aadcees and maber of ing 799 aise aarone. gf esse with ail the aia and sparkle of the finest diamond will be sent you by return mail. Select the one you like best: No. 1—$21.50 2—$17.50 8—$15.50 No. 4— 15.50 6— 12.50 Size must be included when ordering. oe hen LIZNITE GEM RING « comes bang man $4.50, balance '$5.0° mostly aus a paid. beck ax ‘aime voy 4 a } Geta Pyrat vt ng we THE LiZniTe GEM Company “The House of Quality and Pri Dept.511— 1268 N. Welle St.,Chicago, Itt.

the water in the can BASTIN. 98 Convert Your Bicycle Into a Motor Cycle by using the Steffey Attachment PRACTICAL — SUCCESSFUL —RELIABLE. Fits any frame. In use over 21 years. Lowest factory prices. Send stamp for N circulars. STEFFEY MFG. CO., Dept. S, 5025 Brown St., Phila. Pa.

F sentative in each co to use Y end sell the new Mellinger Extra-Ply, Up hand made tires. Guarantee Bond for Uf, 8900 Miles. (No seconds). Shipped, pre; a id on approv: ‘ample sectionsfurnished. Dono boy until you net our Special Direct Prices. Writ $ MELLINGER TIRE & RUBBER C%, - 1004 Oak St., (Kansas City, Mo.

You Can Save *50.00 By recovering your old auto top frame yourself. We make these recovers to fit $6 55 all makes and models of cars. a Any person that can drivea an car can putiton. We furnish instructions. Roof and quar- Parcels Post aid ters sewed together with rear curtain, fasteners, welts and tacks. All complete. Give us the name, year and model number of your car and we will send you our catalogue with samples and quote you cxact price. LIBERTY TOP & TIRE CO. Dept. E8, Cincinnati, O. Wh ] yy continue to Send for (free) illustrated 200-page book. It tells how Stammering and Stuttering can be quickly cured by the most Advanced Scientific Method in the wor'd, THE LEWIS SCHOOL 56 Adelaide, Detroit, Mich. a

Raise Silver Foxes Easy toraise. Larger profits than any other live stock rais- ing. Stands strictest investi-

gation. Recommended by Government. Four different plans. One will suit you. — Complete description sent free. Ask for it today. C. T. DRYZ, Box 1013, EAGLE RIVER, WIS.

CLASS PIN S| FREE CATAIDG five tec wcneuh o ceel Either pin illustrated made with any equal amount of lettering, one or twocolorsenamel, , , s.2| Silver plate, 25¢ ea., $2.50doz. Sterling silver, “a : ant 50c ea., $5.00 doz. Write to-day for newcatalog. & BASTIAN BROS. CO. 288 Bastian Bidg., Rochester, N.Y. xc

Motorcycle Bargains __. mt SAVE 25% to 65% Biyhy on Slightly used and Rebuilt can” cvcles, Side Cars. Johnson Motor #4 Wheels, Evans Power Cycles, Bicycles. Send for Free Bargain Bulletin and ~ Money Saving Message, listing hun- »—) dreds of Bargains in used, rebuilt and “AN) new machines,supplies, accessories, etc.

AMERICAN MOTOR CYCLE co. Dept. 502, 2017 W. Chicago Ave., CHICAGO Hardening, Tempering, Annealing and Forging of Steel By J. V. Woodworth h A Sok ow poencere ge geet yes for the successful ardening and tempering of all steel tools. 320 s, 250 illustrations. Price $3.00 rae. oF POPULAR SCIENCE MONTHLY, 225 W. 39th St., New York

offer poor sort the f will 1 show prov' was t six. { mad tied whic slack lake pulli edge

fast will the spre of t bay the ace Sta pow aral abl; mot lene pre} the tot rep nap the of t $0-( the did the

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May, 1921 Sunshades and Branches to Attract Fish HE inshore waters of lakes bereft of bottom vegetation, weeds, ete., that offer shelter and protection, invariably ar: poor fishing-grounds. If vegetation of on: sort or another is brought into such waters the fish will be attracted and good fishing will therefore be the result. The drawing shows a method of attracting fish that has proved successful in ten lakes in which it was tried. A float is made of boards or old pkanking six feet across and rounded. «Helés are made in its center to permit a rope being tied to it. To this rope is tied®a weight, which is dropped to the bottgm* A little slack is given the rope so t#at when the lake is wavy the float will riee well without pulling up the stone anchor. Around the float nails are driven into the edges at intervals. To these, wires are Can You Measure Up to Her Vision of Manhood The foundation of your- success and happiness in the home, society, business, everywhere lies in a strong, healthy, vigorous body, filled to the brim with vitality and robust health. Weak, sickly, anemic misfits have no chance in the battle of life. They can never win because they haven't the strength, pep and vigor to get started. Sympathy for weakness is polite contempt. You don’t count if you are not physically fit. The strong, healthy, vigorous man is the popular man—the man whom everybody wants fora friend. Success is the Gift of the Strong— physical weaklings must take what is left over and fall back with the defectives and tail-end failures. Make Yourself Physically Fit Let me make a real man out of you—a super-specimen of physical and mental perfection—let me show you how you can be true to the best that is within you and develop your powers to the utmost, Possessing supreme health and strength, you will have the whole world within your reach. You owe it to your Maker, to your parents, your family—yourself—to make your life worthwhile. You were not placed on this earth without a purpose. It was not understood that you would lead an aimless, useless life and end up a mental and physical failure. You must do your full duty to your Creator and to Civilization. You can be the man you should be the man you have always wanted to be. Let me help you with TRONGFORTISM Bowers of branches suspended in shallow waters will attract the fish fastened. Branches, preferably some that will reach nearly to the bottom, are tied to the wires so that the whole forms a wide- - spreading cluster of greenery. If a number The Modern Science of Health Promotion of these floats = set here and there in a Strongfortism has lifted thousands of weak, ailing, impotent, dis- 1 bay, the fish will soon be attracted to couraged men out of the bog of hopelessness and despair and placed | them.—R. P. LINCOLN. them on the Straight Road to Health, Happiness and Prosperity. | Strongfortism has aided Nature in overcoming such ailments as C: | , tarrh, Constipation, Indigestion, Rupture, Nervousness, Bad Bslood, 4 Moth-Balls Are Useless STRONGFORT ed saory Weaknesses and Bad a om results vat ° cc ing and a USING 1e JOC y, otrongtiortism Nas restore¢ 1e Wiane- ‘ as Fuel-Savers — hood they thought lost forever and gave them renewed confidence, d vitality, ambition, success and fitted them for the joys of a healthy happy life. se! can do OTH-BALLS may keep the bugs out the same for you, irrespective of your age. occupation or surroundings. J guarantee of your overcoat and furs, but, according to the United States Bureau of Send for Niy Free Book 4 pap oe eto Standards, they are of no use in aiding the My free book “Promotion and Conservation of power of your automobile engine. Health, Strength and Mental Energy,” will teach you $ The market has been flooded with prep- | how to get rid of your nagging complaints, It arations that smell like moth-balls, prob- will point your way to real Health, Happiness Mr. Lionel Strongfort Dept. 302, Newark, N. J Please send me your book, “PROMOTION AND CON- SI RVATION OF HEALTH, STRENGTH AND MEN- TAL ENERGY," for postage of which I enclose a 10c piece (one dime). I have marked (X) before the subject in which [ am interested . ik alle. « and Success. Asking for it, does not obligate you ably taste like moth-balls, and perhaps Met in any way. Just fill out the Free Consultation ' moth-balls. At least they are a naphtha- | c oupon, mentioning the items on which you want lene product, as are moth-balls. These special information and send to me with a ten cent p, preparations are highly recommended by piece (one dime) to help pay postage, ete. I'll Obesity Insomnia Gastritis Z the manufacturers and dealers as an enemy do the rest. Send for my book Right Now. Headache Short Wind Heart Weakness 4 s $s as J I i I Thinness Flat Feet Poor Circula- y ; " acoli 2PAcG Rupt St h tion yi} to the high cost of gasoline, but the success | I ~mneae Disesdece Skin Disorders os, reported by the users is not due to the i Neuritis Constipation Despondency i Colds Increased Weaknesses Catarrh Height Bad Habits Asthma Pimples Falling Hair Hay Fever Blackheads Weak Eyes a, ° e Neuralgia Biliousness Round Shoulders a naphthalene st all, but to compliance with Physical and Health Specialist Eslcny . iealgueen’ | tsomphueakion m ee for the adjustment | Denartment 302 Newark, New Jersey “sent Poor Memory Development a . % arriage heumatism sreat Streng — In testing out a number of the various | ,Srecial Notice: Lignel Stronalort the Worlds id so-called gas-savers, the bureau found that ist has achieved wonderful results with the Prin- re they had no appreciable effect on the econ- | ciples of Strongfortism. Thousands of his pupils Occupation om omy of an engine, but that some of them soneasteeslt aes — one — 250 did seriously affect the valves by fouling | #“'7°C Unéer nts gutaance. oe enjoy — lent reputation in his profession and can be them. alk depended upon to do exactly as he promises. 99

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Earn $2500 to Be a Signal Engineer Qualify at home in spare time for a big position as Signal Engineer. Get into this great new field of fascinating work where quick success, swift promotion and a high salary await you. Rail- roads everywhere need men who : understand Signal Engineering and SIGNAL ENGINEERING electrical safety devices Book FREE Send quick for big illustrated Book on Signal Engineering and details of our great Free Outfit Offer and our wonder- ful svstem of training which includes a Complete Course in Practical Electricity and Mechanical Drafting. Send postal to day. Don't delay! Get it now! DEPARTMENT OF SIGNALING, Dept. 1206 1924 Sunnyside Ave., Chicago Ill. $500 REWARD Jor TWO HOURS WORK In answer to a request from the Chief of Police, Warren Biglow, the Finger Print Expert, arrived at the scene of the daring robbery of the O— Company offices. $6500.00 in currency was gone. Not a single clue had been found. Almost immediately Biglow turned his attention to a table which had been tipped up. The glossy mahogany showed an excel- lent set of finger prints. The thief might just as well have left his calling card, To make a long story short, his prints were photo- graphed, and matched with those of “Big Joe” Moran, a safe blower. Moran was caught and con- victed on Biglow’s finger print proof. The money was recovered and a $500.00 reward given to Biglow, in addition to his fees—as pay for his two hours’ work. Be a Finger-Print Expert Learn at Home in Spare Time No more fascinating work than this—and big rewards go tothe EXPERT. Thousands of trained men are now needed. The Finger Print work of governments, corporations, police departments, detective agencies, banks, and individuals, has created a new profession. Many experts earn $3000.00 to $10,000.00 a year. And now you can easily learn the secrets of this new science in your spare time-—at home. Any man with a common school education can become a Finger Print Expert in a short time. FRE Finger-Print Outfit and Large Illustrated Book We are making a special, limited offer of a complete Professional Finger Print Outfit, and a Course in Secret Service Intelligence, both absolutely FREE Mastery of these two professions offers you a bril- liant career. Write quickly for illustrated fre« book on Finger Prints which explains this wonderful training in detail Don't wait—mail the coupon NOW. You may never see this announcement Address UNIVERSITY OF APPLIED SCIENCE Desk 1205 1920 Sunnyside Ave., Chicago, III. UNIVERSITY OF APPLIED SCIENCE Desk 1205, 1920 Sunnyside Ave., Chicago, III. Gentlemer Without any obligation whatever send me your new, fully illustrated, FREE book on Finger Prints, and your offer of a FREE Course In Secret Service Intelligence. again. Name sees es ° Age Address ee ee ee State Weaving a Chair Seat from Tire Strips COMFORTABLE chair bottom may be made of strips cut from an old automobile tire. The method is as follows: Cut the beads from an old tire and then cut it into strips about 1 in. wide. To do this the tire need not be cut in two, but may be cut into one spiral strip. The rubber can be peeled from these strips and sold as junk in the usual way. The fabric can be peeled apart in one or two ply. When this is done, we are ready for work. Select a chair that has had a split or cane bottom. Double one of the strips back about 1 in. and tack it to the under side of the rung, close to the post. Bring the strip over the rung and wrap it around once if desired. Cross to the opposite rung from the top and come around under the rung from whence we started. Leave a space between the strips about equal to the thickness of the fabric strip. The whole bottom is covered one way with the strips. When it becomes necessary to splice, use split rivets and cut 7 the strips so that all splices come underneath. Weave a second 7 , lot of strips across, ' securing their ends wf as described. The } bottom may be woven in squares, or if a neater jobis desired, the cross strips may be put under two and over two for the first row, the second row divid- ing the first pair and then put in as the first row, under two and over two, as shown in the picture. Before the last strip is woven in, excelsior or other padding material may be stuffed in the space made by the rungs, but this is not necessary as the seat will not sag even if not stuffed.—E. E. LAMB. noth - | E E { © of This is one pattern that may be woven from tire strips Bore Holes in Wood with a Chisel-Pointed Nail HE reason so many screws are driven in with a hammer is often because no small boring-bit is available for making holes for them. Some workmen, in an emergency of this kind, will take a nail of suitable size, drive it in part way, withdraw it with a claw-hammer, and insert the screw in the hole thus made. A more workmanlike method is to grip the nail in the jaws of a brace and use it in the same way as you would a bor- A wire nail will ing-bit. With a little extra pres- drill a smooth hole through wood “a sure on the brace, the nail will make a hole as_ rapidly as a bit and, in some cases, with less dan- ger of splitting the wood. Where there is danger of splitting, be- cause of the hole being required near the end of the board, the nail should be ground, cr filed, to a chisel-point, as shown in the accompanying illustration. As a matter of fact, if there are many holes to be bored, it will pay to grind the nail in this manner, whether there is danger of splitting or not, as the chisel-pointed nail cuts, or scrapes, its way through, while the common pointed one merely pushes the fibers apart. 100 Popular Science Monthly Do you know that Clear-Tone —the wonder-working lotion —used like toilet water — Clears Your Skin of Pimples, Blackheads, Acne Eruptions, Enlarged Pores, Oily or Shiny Skin? Hlegant after Shaving. Indispen- sible for sensitive and refined women. GUARANTEED to banish eostentiy blemishes easily and quickly, and leave the skin clear and smooth. “A Clear-Tone Skin’’ This Free Booklet tells how you can easily and quickly at home obtain a clear skin, free from all blemishes, like Nature intended you to have. Thousands of copies of this interesting books are distributed every month. Clear -Tone isnot a cure-all ora mail-order treatment, but a scientific, reliable SKIN LOTION, perfected after 15 years personal experience by Mr. E. S. Givens, who knows every embarrassment one has to suffer with a bad complexion. Endorsed and prescribed by physicians, druggists, and thousands of enthusiastic users, and sold on a direct and posi- tive guarantee of satisfaction or money back! The marvel of Clear-Tone is that it clears the com- plexion so quickly, no matter what the cause. Clear -Tone 52s had an unpre- cedented success as evi- denced by thousands of voluntary letters written by men and women who had very bad blemishes and tried various soaps, ointments, and doctors without relief. Read These Letters! From U. S. Hospital-- ‘‘Find myself improving wonderfully. Any one I see that has skin trouble your wonderful Clear-Tone will be recommended.”’ Chas. A. Rein,U.S. Hospital 41, Staten Island, N.Y. From a Barber--‘‘Have been abarber for 30 years and never saw anything as good as Clear-Tone. All barbers should know about it.’ Otto Van Burin, Kansas City, Mo. From a Musician--‘‘I am obliged to be in public a great deal and my complexion was a great embar- rassment. Clear-Tone improved me so greatly that I strongly recommend it.’’ C. H. Lindeman, Steu- benville, Ohio. From a Lady--‘‘I cannot thank you enough for all the ood it has done me. One bottle has cleared my ace wonderfully.’’ Miss Mary Yonks, Haver- straw, N Y. From a Soldier--‘‘It is certainlywonderful.’’ Louis Langer, Troop F, 3rd Cavalary, Ft. Ethan Allen, Vt. From a Flyer--‘‘Cleared my face of Acne.’’ H. J. Howald, N. H. Station, Pensacola, Fla. People Amazed--‘‘Has cleared my skin completely of pimples and blackheads. Everybody who sees meis amazed.”’ KR R. Wilson, Pearson, Ga. a Thousands of Others--men and women--praise Clear-Tone. We'll gladly send copies cf most in- teresting testimonials. FRE Simply send name today for FREE booklet, ‘‘A Clear-Tone Skin’’ mes telling how I cured myself after being afflicted for 15 years, and my $1,000 Guar- antee to clear your skin of the above blemishes. E. S. GIVENS, 153 Chemical Bidg., Kansas City, Mo. a cai SR

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May, 1921 ee pe ivi aig renee Tuan CON Wy» NATIONAL | ‘BEDS = » orm S e 2

ON CREDIT i vis oy in Diamond Rings Solitaires, Clusters. ‘| Latest plain, engraved and pierced mountings. The | Diamonds are magnificent gems, set in White, Green [5 and Yellow Solid Gold. See Catalog. Priced F at | $85, $125, $150, $200, $250 WP | SendforCatalog| Wrist Watches , # 128 pages of bargains. | See Cataloe for Wrist 4 Whatever you select will] Watches — Silk Ribbon : {3 be sent prepaid by us. You| and Extension Link | see and examine the | Bracelets, warranted for \- article rightin your own | 20 years, priced from $22 hands. If satisfied, pay | up; Solid Gold, $29.50 up. one-fifth of price and keep a WATCHES | it, balance in eight equal Piri eal 1 pb na | amounts, payable monthly. Liberty Bonds Settee _LOFTISBROS.&CO. | THE OLD RELIABLE CREDIT JEWELERS Dept. N-871 108 N. State St., Chlenge, nm. | STORES IN LEADING CITIES p OR” ve LLL NNR ERLE OK

“Reo” Cluster Metal S Shingles, v- -Crimp, isse gated, Standing Seam, Painted or Galvanized Roof- SS. Sidings, allboard, Paints, etc., direct to you at Rock-Bottom Factory Prices. Positively greatest offer ever made. Edwards ‘‘Reo” Metal Shingles cost less; outlast three ordinary roofs. No paintin orrepairs. 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 Cage Ask for Book oa. ° = ew eRe er ete, erences

LOW PRICED GARAGES * Lowest prices on Ready-Made Fire-Proof Steel Garages. Set upany place. Send postal for ; Garage Book, showing styles. THE EDWARDS MFG. Co., 548-598 Pike St., Cincinnati, 0.

i Learn to Play the Violin In Your OWN HOME Our method of teaching is so simple, plain, and easy that you beginon a piece with your first lesson. In half an hour you can play it. Complete course under personal direction of Prof. A. Hinchcliffe, a musical director and violinteacher of prominence for the past forty years. Low price includes Violin, Bow, Case, Chin Rest. Rosin, runing Pipes for all strings, extra set of strings and complete conservatory course of instruction. Special arrangement for lessons if you have your own instrument. Satisfaction guaranteed. Write to-day for full particulars—free ! First Hawaiian Conservatory of Music, Inc. Dept. 239 233 | Broadway, New York City

“Lighting Fixtures” Ready to hang. Direct from manufacturers. Completely wired including glass- ware. Send for Catalogue No. 20 ERIE FIXTURE SUPPLY CO. Desk A, Erie, Pa.

To Obtain Transparent Ground Glass for Focusing XNROUND glass has two different sur- faces. One is smooth and even and the other is rough and minutely hilly. The hilly side of the glass makes it valuable for photographic focusing. But the image thrown on the glass is not always as sharp as we desire it. How is the object to be sharply focused? The ground glass can be taken out and ordinary window-glass substituted, and then accurately focused with the aid of a hand-lens. But when one has done this a

Good Pay for You in Auto Business Hundreds of good jobs paying around $50 a week are open for Swee- ney trained men. Garages, repait shops, welding or vulcanizing shops, automobile agen cies, etc., have

written to the

E.J.SWEEN EY Sweeney School PRESIDENT asking for con pe-

74 or $5 wii"Bhy A Standard, Guaranteed

With Every Modern Writing Convenience Write Today For Illustrated Circular Explaining Try-Before-You-Buy Plan SMITH TYPEWRITER SALES Co. (Harry A. Smith) 306 —218 No, Wells St.,Chicago, Il,

If you use a ground glass for focusing your camera, improve it by providing a clear window in it dozen times or more, one realizes how much time is wasted by this method. The rough side of the ground glass, when a film of water is placed on it, becomes as transparent as window-glass and one can focus through the film of water. It is better still to place a drop of Canada balsam in the center of the glass on the rough side and carefully place a micro- scopic cover glass on it. This makes the center of the ground glass perfectly trans- parent.—E. BADE. Spherical Lathe Centers for Cutting Tapers HEN long tapers have to be cut and there is no special attachment pro- vided, there is only one method left to set the tailstock over in accordance with the angle of the taper and cut with the \} [ E ig Cutting tapers on a lathe with conical centers will soon wear out the centers and make the work inaccurate object in that position. The effect on the conical centers with which all lathes are equipped is highly unsatisfactory. Figure A shows the position of the work in hand, held by the tailstock in perfect alinement with the headpiece. Figure B shows the wearing effect of the point of the set-over tailstock against the sides of the conical recess. 5 It is evident that there is great wear on the conical recess that requires frequent adjustments of the tailstock spindle. The 101

The is the auto a in eigh of Pr: under out over 5,000 army mechanics during the war. Many thousands of Sweeney trainec able pe Ani is that No books are used and everything ts 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. Che numbe repair want 1 wet two m Ple ise LEARN IN 8 WEEKS THE Mr. Sweeney publishes a beautifully illus trated 72-page catalog that tell all about opportunities right now in the auto and tractor business. He will send this free without any obligation, together with the Sweeney News, a1 1 ‘resting paper and full information about 1e demand for trained men This literature . 1inlv 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. 876, Kansas City, Mo.

For Big Free Catalog Mail This Coupon EMORY J. SWEENEY, President Dept. 876, Sweeney Building Kansas City, Mo Please send me free without any obligation on ect part your 72-page catalog and your Sweeney School News Tell me of the opportunities in * Auto and Tractor Business Name P.O r of applications from garages, a head mechanic and will pay $50 k’’ writes one concern. ‘‘Want tent mechanics. Sweeney School at IKKansas City world’s largest and most famous nd tractor school. It trains men it weeks by the Sweeney System ictical Experience. This system Mr. Sweeney's direction turned 1 men hold responsible and profit- sitions in the automobile business. nteresting feature of this training no previous experience is required. Sweeney School publishes a great shops, etc., asking for men. “‘I echanics. Pay 60 cents an hour, wire,’’ writes another. SWEENEY SYSTEM state

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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 CAN YOU {/ think of a simple, practical idea } @ that will fill one of the many ree quests we have on file for new inven- tions? It may mean a fortune for you, Thousands of things are needed RiGut Now. Your brainscan help. Send toe 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— it is free. PATENTS ADVERTISED For SALE FREE We help our clients, Without charge, to get the dollars out of their ideas —having facilities none others possess. fice In INVENTION And book at once. 5 MANUFACTURING AMERICAN SUPPLEMENT. INDUSTRIES, INC. mar tblished for the Send for free sample copy. One year's sub- 6cription 50c¢ 201 Patent Dept., WASHINGTON, D. C. MAKE MONEY AT HOME You can make from $1 to $2 an hour writing show cards in your spare time, quickly and easily learned by our new simple method. o canvassing or soliciting. We sell yur work and pay you cash each week. Full particulars and booklet free. Write today. AMERICAN SHOW CARD SCHOOL 206 Ryrie Building, Yonge & Shuter Streets, Toronto, Canada angle of the taper, owing to the effects of the wear, constantly changes and the cut becomes inaccurate. An English mechanical engineer suggests as a remedy the use of spherical centers as illustrated in Figs. C and D. The end of the tailstock is provided with a cup-shaped recess into which a ball of hardened steel fits with accuracy. Instead of the conical recess that usually forms the center of the The effect of taper-cutting with the tail-stock out of alinement is shown object to be turned, a similar cup-shaped recess is sunk in the end of the piece. Figure C shows the position of the parts with the tailstock in perfect alinement with the center of the headpiece. Figure D illustrates the relative position of the parts in cutting a taper at a considerable angle. As will be seen, there is no interference and no probability of excessive wear that might disturb the angle of the work while the cutting is done. Paper Boxes for Domestic Use Are Easily Made tet anrtebod you are in need of a paper box and cannot find one already made of the required size and shape. By following the directions illustrated in the accompanying diagram, you will be able to make your own paper boxes tight enough to hold solids, even in powder form, and if made of paraffined paper, capable of hold- ing liquids. First ascertain the exact dimensions of the box you need, then mark on a sheet of oe FOLD BACKA~ Yon 7) FOLD DOWN ' FOLO ON DOTTED LINES ! ' " } j ‘ Paper boxes folded as illustrated here form useful containers very stout packing-paper or paraffined stock, a line for folding in accordance with the diagrams in the lower part of the illus- tration. After all the lines necessary have been drawn, crease and fold the paper as shown in the upper part of the illus- tration. It is obvious that the dimensions of the box may be varied to suit the requirements in each case, once the principle is under- Popular Science Monthly BOOKS ELECTRICITY Electrician’s Wiring Manual By F. F. SENGSTOCK, E. E. contains all the information needed for the proper installation of lighting and power sys- tems in houses and other buildings and com- pletely covers the field of inside wiring and construction im accordance with the new National Electrical Code. Profusely illustrated and contains many tables and formulas. Pocket size, flexible binding; 448 pages Price, $2.50 Experiments With 110- Volt Alternating Current By J. D. ADAMS Here at last is a book that develops a prac- tical working familiarity with the alternating current—the form in which electricity is used in every home. The author shows how this can be done in an interesting and inexpensive ay. The only way to gain a thorough understand- ing of electricity as it is used commercially is by direct Ppersonai experiment. The knowledge thus gained is of vastly more value and im- portance than that acquired from the perform- ance of the stereotyped series of battery exper- iments so uniformly described in the text-books. 256 pages, 135 illustrations Price, postpaid, $1.75 Armature Winding By DAVID P. MORETON A practical analysis of armature windings for direct-current and alternating - current machines, including rules and diagrams for reconnecting induction motor armatures; pro- fusely illustrated with wiring diagrams and photographs of coil-winding apparatus. This volume is particularly adapted for the purpose of home study and self instruction. 204 pages, 232 illustrations, flexible binding Price, postpaid, $2.60 Small Motors, Transform- ers and Electromagnets By H. M. STOLLER, B.E., M.S. detailed methods Unique, typical complete designs and actual construction Practical, tells how to rewind used motors for changes in voltage, speed, frequency, etc. Authoritative, yet simply written, and equally valuable for the amateur, repair man and elec- trical engineer. giving 328 pages Price, postpaid, $3.10 POPULAR SCIENCE MONTHLY stood.—PETER P. LEMBO. 102 225 West 39th Street New York City nead loose head engin Co rer of pu is to better harm and a

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,. @ Fy Vw” led ds for etc. ally lec- LY May, 1921 Automatic Coolant Feed for a Drill-Press "T*O-DAY all shops use a ‘‘coolant’”’ of emulsified oil or in some few cases straight lard oil for cooling the drill and aid- ing the cutting in drill-press work. One of the disadvantages of the usual gravity feed x pump feed is that the operator will go away from the machine at night and forget to turn off the oil, causing waste. The illustration shows a device designed by the writer to overcome this trouble and to put such apparatus in the automatic It is designed to be attached to the spindle of the drill-press. A is the tank or receptacle proper of cast iron bored out to take the spindle, and held up in place by a set screw. FP are two copper tubes of %- inch diameter soldered on one end to the needle-valves C, the other end leading to i) | it ‘| | | | \ PRILL PRESS fill (|| SPINDLE = siil/i_ | Il | \ class. a = COOLANT ye. eee Ze The cooling oil, supplied to the feeders by centrifugal force, will be fed to the drill only when it is working the drill. These pipes are secured to the tank A by clamps £. D is a filler plug for replenishing the supply of coolant. The action is as follows: Start the ma- chine and as the spindle starts to revolve, the centrifugal force throws the coolant out to the largest diameter of the tank, thus overcoming the force of gravity and forcing the coolant against the ports of the needle-valves CC, from whence gravity W. Burr BENNETT. acts. Avoid Shellac and Save the Cylinder-Head Gaskets “T° HE copper-asbestos gaskets used under the heads of detachable head motors, invariably stick so solidly when these are put on with shellac, that removal of the head for cleaning out carbon necessitates loosening the bolts or nuts holding the head on about two turns and starting the engine to shake or lift the head sufficiently to remove. A more satisfactory and correct method of putting on these cylinder-head gaskets is to coat each side with cup grease or, better yet, graphite grease. This does not harm the gasket and a positively water- and air-tight joint is certain. @ VICTOR J. EVANS & CO. Patent Attorneys Philadelphia Offices 135 S. Broad Street Chicago Offices, 1114 Tacoma Bldg. —— ow a ee oe ee ee PATENT SPECIAL OFFE TRADE-MARKS COPYRIGHTS FREE OPINION AS TO PATENT ABLE NATURE 3efore 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. Countries. Our Three Books Mailed Free to Inventors Our Illustrated Guide BOOK HOW TOOBTAIN A PATENT Sent FREE on Request Contains full instructions regarding Patents, Trade-Marks, Foreign Patents. 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 l'rade-Mark Protection and gives information regarding unfair competition OUR FOREIGN BOOK We have Direct Agencies in all Our Foreign Write for our illustrated Guide Book on Toreign Patents. SPECIALIZATION Our Staff The field of invention is so vast that it is impossible for any one man to become an Only those practically skilled in the class to which the invention relates are capable of rendering efficient 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 expert in all the different elasses of invention. lines of invention. the invention relates. sery ic e. For Each case is placed in charge of experts in the classes in which 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 ence acquired by a long and successful practice. to secure the broadest possible patents that the inventions will warrant. We spare neither skill and experi- time nor pains 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 bene fit of our clients Branch Ill., and San Francisco, Offices in New York City, Philadelphia, Pa., Pittsburgh, Pa Cal. , Chicago, These branch offices being located in these large commercial cities, Office located nearthe U. S. Patent office, in Washington, enables us to more business of our clients, particularly as the branch offices are in constant Office and fully equipped to handle patent business in all its branches. Highest References—Prompt Attention— Reasonable Terms New York Offices 1007 Woolworth Bldg. as described above. 103 Pee Address... a i ns lets dele aici da, adil nie ea ae eal ae a ee ee ae together with our Main promptly handle the touch with the Main Pittsburgh Offices 514 Empire Bldg. San Francisco Offices, Hobart Bldg. Main Offices, 760 9th Street, Washington, D.C. Gentlemen: Please send me FREE OF CHARGE your books

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will give our opinion as to its patentable nature. RANDOLPH & CO. 130 F St, N. W., Washington, D. C. PATENTS Booklet Free Promptness Assured Highest References 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 of model for patentability 4 opinion and exact cost of patent. Our book mm ‘How to Obtain a Patent” Sent Free on re- quest. It tells how to apply for Patents, Trade Marks, Foreign Patents, Copyrights, etc.; gives information on Patent Procedure; tells what every inventor should know. Thousands of Inventors, who are our clients, are our references. CHANDLEE & CHANDLEE, 25 Years‘ Experience 425 | 7th St. Washington, D. C. PATENTS SECURE A PATENT, send for Our Guide Book, HOW TO GET A PATENT, sent Free on request. etc. Send model or sketch and description of your invention and we IF YOU HAVE AN INVENTION and DESIRE TO LEARN HOW TO Tells our Terms, Methods, potter ee -- —_—_ = a n 4 vs) real ical 4 || I. T. S. Patents Five years ago, practically without capital, J. G. Tufford, Elyria, Ohio, and his associates Smith and Ingwer started business with the now well-known I, T. S. Rubber Heel under the Tufford U. S. and foreign patents obtained through Lacey & Lacey. Fourteen tons of these heels are now produced daily. The profits already amount to many hun- dreds of thousands of dollars and foreign patents have been sold to the extent of $550, .00. That demonstrates the financial possibilities even of an extremely simple invention of merit properly patented. Read PATENT-SENSE “dhe Book for Inventors & Mfrs” By Ret M LACEVELACEN, Bee tet nC YOUR PATENT ATT’Y To be most e mc ient must be a man of various parts. In Att’y W. E. Baff you find the rare combination of proven tech nic: al skill protecting inventions, coupled with first hand knowledge of marketing thereof gained Ask for booklet. BAFF PATENT LAW OFFICE 311 Main Street as an author of a standard work. 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. Cc. THE BOY ELECTRICIAN Practical Plans of Electrical Apparatus for Work and Play with an Explanation of the Principles of Every-day Electricity. $2.60 Pi sStpa ud, POPULAR SCIENCE MONTHLY, 225 W. 39th Street, New York DFOR SI GENO =i fait= el DON’T LOSE YOUR RIGHTS TO PATENT PROTECTION i Before disclosing your invention to anyone B send for blank form **EVIDENCE OF CON- }! CEPTION” to be signed and witnessed. A sample form together with printed instruc tions will show youjust how to work up your evi- B® 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. Oursche dule of fees & willbe found reasonable. The form ‘Evidence of Conception,”’ sample, instructions relating to obtaining of patents and schedule of fees Mm sent uponrequest. Ask for them,—a post card ® will do. PATENTS AND NV TRADE MARKS 274 Ouray Bldg. WASHINGTON, D. C. Originators of forms ‘Evidence of Conception.” Worcester, Mass. ontains valuable information and advice to inventors on securing Patents. Send model N\\ or sketch of your invention for Free Opinion Meemal| of its patentable nature. Prompt service. - 20 years experience. White today. TALBERT & TALBERT 4911 TALBERT BLDG., Washington, D.C. THE MODEL T FORD CAR Its Construction, Operation and Repair, Including the Fordson Farm Tractor, F. A, Lighting and Starting System, Ford Motor Truck. Price $2.00 Postpaid. POPULAR SCIENCE MONTELY, 225 W. 39th St., New York To “a Man With an Idea I offer a most comprehensive, ex- perienced, efiicient 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. =f e My experience and familiarity with 2 — i; “ ————— — —~ * . oy, a aa ne EN ET ee = : » various arts, frequently enable me to accurately advise clients as to probable patentability before they go to any expense. Booklet of valuable information and form x for properly disclosing your idea, free on rf request. Write today. RICHARD B. OWEN i Patent Lawyer %f 6 Owen Building, Washington,D.C. |} { a 2276-D Woolworth Building, } is New York sive Popular Science Monthly A Wooden Aspirator for Cistern Draining A “Y” aspirator that may be used to drain a cistern with the city pressure is very useful, but it is impossible to get the fittings unless one makes a pattern and has a casting made and machined. I made one by drilling a piece of pine scantling as shown. In working position the double end of the Y is up, and the single end down. The hose FAUCET —>s op ad U/ fi Y /, fA rose UY St Lp OSTRINVZ stction With this homemade aspirator you can empty your cistern through the sink drain by turning on the cold-water faucet that leads to the cistern is connected with one of the double branches and the hose connected with the supply line to the other. When the water is turned on, the force of the stream rushing down with pressure will suck the air out of the hose leading to the cistern, producing a vacuum, and the cistern water will rush to fill the space and thereby run out. The water will be drawn out of the cistern as long as the city supply is turned on. Force the rubber hose into the openings of the wooden Y and seal with putty.—JOHN L. DOUGHENY. Develop Your Muscles with a Piece of Old Tire “HE rubber fabric of tires possesses great resiliency and, in accordance with its thickness, offers greater or lesser resistance to bending. This quality may be utilized by budding athletes for the devel- opment of the muscles of their hands. Cut a piece about 5 in. square from the thickest part of the old tire, place it in your Bending a piece of rubber from an old tire as shown here will strengthen your grip if practised systematically hand as shown in the illustration, and bend the rubber by closing your hand as far as possible. You will find that the rubber offers considerable resistance, and at first it will tire your hand to bend the rubber even a few times —C. E. ETCHES. An The tc aS SIV the be with w cloth 1 Ra the ter draft tion, 1 inside Th as to ating The « side ¢ arran a posi fan, t a reli Mal A. untw flapp pel tl prine rubbi hook Tr eran and § At vhi rd

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May, 1921 An Iceless Refrigerator for the House HE arrangement shown is made of a 3-in. pipe frame, covered with cloth. Ihe top pipes on which the cloth is hung has small holes drilled about 4 in. apart on the bottom sides. When the can is filled with water, or the city water turned on, the cloth becomes saturated with water. The Rapid evaporation of the moisture in the cloth of this cabinet causes the temperature within to fall draft from the fan creates a rapid evapora- tion, which greatly reduces the temperature inside the cloth. The frame is made triangular in shape so as to present the greatest possible evapor- ating surface to the draft from the fan. The opening in the cloth is made on the side opposite the fan. The shelves can be arranged to suit the individual need. With a positive draft assured by use of an electric fan, the arrangement shown will prove to be a reliable cooler.—F. G. KOPER. Make This Mechanical Toy Fish that Swims A MECHANICAL swimming fish can be 4% made with very little trouble. The untwisting of a rubber cord causes the flapping movement of the tail so as to pro- pel the fish through the water on the same principle as used by the real fish. The rubber cord or band is stretched between power circuit in the factory. Single terminal— with cord and plug—Non- Reversible. SPECIAL PRICE ON MOTORS OF $13.00 EACH. washing cr ironing machines, 410-420 No. Hoyne Ave., 1/, HP Motors $13.50 We offer 5000 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 Remarkably simple in design and sturdy in construction. F ventilation system prevents overheating. These motors carry the Manufacturers ONE 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. THREE OR MORE These Motors are ideal for use in the home on or on the bench; 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. in the Northwestern Electric Company Fan-cooling YEAR Double terminal—can be reversed from out- side cord and plug not furnished. Chicago, Illinois “BOWLEGSandKNOCK- KNEES" | UNSIGHTLY SEND FOR BOOKLET SHOWING PHOTOS OF MEN WITH AND WITHOUT The Perfect Leg Forms PERFECT SALES CO.,140 W.Mayfeld Ave., Dept. 45, Chicago, il. TREMENDOUS SAVING IN COST Easy fascinating work, with our SIMPLIFIED PLANS We furnish bhue prints, diagrams, motor, ‘cabinet pieces, ready-built horn, etc You don’t need t e a cabinet-maker. a few hours acaemeuing and you will have a fine in strument at one-quarter the regular retail price, GENTS MAKE MONEY making and selling these instruments. Write today for full details and our FREE OFFER. Address:— MODERN PHONOGRAPH SUPPLY CO. 558 Springer senens 313 So. Clinton St. CHICAGO, ILL. Build This Phonograph Y ourself hooks on two spindles. The front spindle has the shape of a crank that comes out of the fish’s mouth and serves for winding up the rubber band. At the other end is a crank-shaped piece SWINGING TAIL RUBBER BAND - , HINGED This toy fish is propelled through the water by the motion of its tail, atwisted rubber band supplying the power that rotates when the rubber band un- ‘inds, and this produces the back-and- rth motion of the fish’s tail. The end of the crank works in a loop of vire in the shape of a slot, so that the revolving movement of the crank produces ‘ to-and-fro movement of the hinged wire part, as will be readily seen in the drawing. in this wire frame is mounted the tail, which flaps back and forth so long as the ATwo-Cavity Mold doing the work of eight cavities —A Single Cavity Mold doing the work of four cavities. No reducing shelle—heat apeted direct to raw rub- ber—perfect cure. Instantly changed to take from 3 in. to 5% in. tires, cord or fabric. and at the same time maintaining full steam pressure without the use of steam hose or gasket. Overcomes ‘“‘buckling’’—Tires cannot stick in the Mold. Saves you labor, time, space, fuel and money. An absolute necessity in every up-to-date Vulcan- izing establish ment. SEND US YOUR OLD EQUIPMENT We take used equipment as part payment on this latest invention. What equipment are you using? Write us for offer on ‘‘trade-in. A MODEL FOR EVERY SHOP No shop too large or too small—They all need this quick-working, acc urate curing, marvelous machine that does the work of eight cavities. Write us for descriptive matter and prices on this Super-Vulcan- izing Machine—its wonderful work producing pos- sibilities will astonish you. MAKE MORE MONEY We have under operation well managed schools to teach Tire Repairing. There is one near you—- Write for address. Many towns are in need of “WESTERN” trained men to make thousands of dollars repairing tires. You can be this man. Let us tell you how easy it is fora “WESTERN” trained student to own the leading shop in his town — How you can become a successful business man. Drop the pa ag punching time clocks—Don't be bossed—be boss. Write tor our plans to establish ‘ a shop of your own and address of nearest school. GENERAL OFFICE AND FACTORY: Main Schools and Factory Branches Located at: ord untwists. The Super VULCANIZER DOES THE WORK OF EIGHT CAVITIES WESTERN RUBBER MOLD CO., 313-325 No. 3763 Woodward Ave., Detroit, Mich. Crawford Avenue, Chicago, I). 15 N. Summit St., Akron, Ohio 105

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Ey Pieniinn THUY National System

CANADA Calls You! 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—Geor gian Bay—Lake of Bays—Kawar- tha Lakes Timagami — Nipigon — Quetico— Minaki—Lower St. Lawrence and Maritime Provinces. Fishing, boating, bathing, golf. summer play-ground in the great out-of-doors. Jasper Park, Alberta, ar id 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. Boston, 294 Washington St. Minneapolis, 518 Second Buffalo, 1018 Chamber of Ave., South Commerce Bldg. New York, 1270 Broadway Chicago, 64 West Adams St. Pittsburg, 805 Park Bldg. Cincinnati, Traction Bldg. St. Louis, 305 Merchants Detroit, 527 Majestic Bldg. Laclede Bldg. Kansas City, 710 Railway San Francisco, 689 Market St. Exchange Bidg. 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. H. Melanson. Passenger Traffic Manager, Canadian National Railways, Toronto.

Gibson Instruments Mandolin, Mandola, Mando - Cello, Guitar, Tenor-Banjo, Mandolin - Banjo, Cello-Banjo, Guitar-Banjo, Harp- Guitar, Mando-Bass —

ae “< . 4s Select your Gibson now. ak 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, Church 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, we will make liberal allow. ance on 8 Gibson. Write Today for Free Book, Catalog, Free Trial Offer, information about Wm. Place, Jr. Book and the instrument you prefer GIBSON MANDOLIN-GUITAR OO.

Easy to Play, tf ‘(Easy to Pay

485 Parsons &t., Kalamazoo, Mich., U. 8 A.

Finding New Uses for Old Things What use have you for some of the “junk” in the attic or cellar? Popular Science Monthly will pay ninety dollars for the best answers HERE is the old baby-carriage, the old stove, the old bureau, the trunk, and the leaky’ wash-boiler. The attic also contains old phonograph needles, safety-razor blades, carpets, curtains, chairs, tables, picture-frames, hat- boxes, etc. Have you been able to save money and add a convenience to your home by pressing some of these things into service again? If you have, you probably had tu get the household tool-kit out to help you. Sit right down now and tell Popular Science Monthly what changes you made and how you made them. It makes no difference what you changed, as long as it wasold. You may win one of the prizes. The Popular Science Monthly offers three prizes for the best answers— a first prize of $50, a second of $25.00, and a third of $15.00. These will be awarded in accordance with the rules outlined below. Rules Governing the Contest (1) Contestants are not limited to the number of ideas, but only one method can possibly win the first prize, only one the second, and only one the third. The con- test is open to everybody. (2) The use of the old piece of junk must be shown clearly, either in a photograph or in a drawing. If a drawing is sent in, it need not be made by a skilled draftsman. It is sufficient that it should be intelligible. While pen- cil sketches will be considered, contestants are requested to make their drawings in ink on heavy white paper. The views should be sufficient in number to set forth the writer’s idea very clearly. The con- testant’s name and address should appear on each sheet of drawings. (8) The drawings or _ photo- graphs must be accompanied by a description, preferably type- written, in which the method is clearly given. It must be written on one side of the paper only, and it should not be more than 500 words in length. The name and address of the contestant should appear in the upper left-hand corner of the first sheet of the written description. (4) The drawings and descrip- tion entered by contestants must be received by the Popular Science Monthly not later than 5 p. m., on June 15, 1921. (5) The judges of the contest will be the editors of the Popular Science Monthly. 106 (6) The first prize of $50 will be awarded to the contestant who, in the opinion of the judges, has suggested the best use for an old piece of junk. The second prize of $25 will be paid to the contestant who sub- mits an idea next in merit. The third prize of $15 will be paid to the contestant who sub- mits an idea third in merit. (7) The winners of the contest will be announced in the earliest possible issue of the Popular Science Monthly. A description of the ideas that win the three prizes offered will duly appear in the pages of the Popular Science Monthly, together with the names of the winners. (8) The editors of the Popular Science Monthly shall have the right to publish meritorious manu- scripts that do not win a prize. The regular space rates will be paid to the contestants who sub- mit the manuscripts thus selected. (9) When a contestant submits more than one idea, the descrip- tion and drawing by which each is set forth must be sent as a sep- arate unit. (10) Manuscripts or drawings will be returned to contestants if stamps are enclosed. (11) Send drawings and specifi- cations to the Editor of the New Uses for Old Things Contest, Pop- ular Science Monthly, 225 West 39th Street, New York City. Popular Science Monthly

tor tne ing Sm™ 4©

Page 87

May, 1921 An Electric Blower for the Blacksmith Shop N electric fan was employed on a blacksmith’s forge to relieve the black- nith from turning the blower by hand. Four stove-pipe elbows were cut in half, dered together, and used as the casing r the fan blades. More stove-pipe was ised to convey the air to the forge. To egulate the pressure of the blast, a slot was it in the side of the pipe, just wide enough +» let a flat piece of tin slide through. This »iece of tin was provided with a handle for the purpose of moving it in and out. A

An electric fan will supply a steady draft to the forge fire, leaving both hands of the blacksmith free gate, projecting from the pipe at right angles, was fastened on the pipe just over the slot. This gate supports the slide when it is pulled out and allows the maxi- mum pressure of air to flow through to the forge. By changing the position of the slide, the fire in the forge can be regulated to suit the mechanic. This arrangement leaves both hands free to use tongs or any other tools that may be wanted. When the gate and slide is placed near the floor, it can be operated with the foot.—R. C. SMITH. Improvise an Extension Wrench for Large Work Op reengg meer plumbers or steam- fitters, though well equipped with tools, are confronted with the difficulty of removing pipe joints too large even for their largest wrenches. The accompany- ing picture illustrates how a wrench of in- adequate size may, in an emergency, be extended to grip the large screw joint. A piece of stout wire is looped around the mov- able part of the jaw of the wrench, while the other ends of the wire are firmly twisted around the rocker of the handle. By “WIRE this expedient the capacity of the wrench can be ex- tended easily from 14 in. to 1 in., ac- STILLSON cording to the size WRENCH of the wrench and the diameter of ae aan

A makeshift, useful in the pipe. — WM. an emergency JACKSON.

Learn Mechanical Drawing Men Needed Salaries $35 to $100

Are you earning less than $35 a week? Can you reasonably expect your present position to pay you $35 to $100 a week in the near future? If not, this offer will interest you. We offer to qualify you for a profession which, at the very start, pays higher salaries than the average man receives. We offer you the best personal service obtainable. We offer you personal instruction in mechanical drawing and teach you expert Draftsmanship in your spare time, at your home, by mail, in the same practical way that you would learn it in any big Drafting department. We offer to qualify you for one of the many high salaried positions in the Drafting field, and to keep you in touch with openings for Draftsmen in big machine shops, industrial plants, manufacturing concerns and United States Government Departments. We guarantee to start you on real Drafting work at once qualifying you as a thoroughly trained professional Draftsman, capable of succeeding from the very start. One of the many outstanding features of our training is that it qualifies you in an unusually short time.

I personal y stand back of the Columbia School of Drafting—founded directed and owned by myself and guarantee the training given by it to be abgplutely as represented The work of each one of our students has my personal superv sion We seek ‘Quality students rather than ‘‘Quantity,”’ as our proposit on & of the highest charaeter in every respect Roy C. Claflin, President.

Become a Chief Draftsman You cannot make a mistake by taking up mechanical drawing. The field is not crowded, nor can it be. No single profession to-day offers better opportunities. The great need for trained Draftsmen continues to increase. Each step forward in mechanical develop- ment creates a need for more trained Draftsmen. Promotion in this: field is sure and certain. Men who start as Draftsmen are often advanced to Chief Draftsmen, Chief Engineer, Production Manager or other high salaried positions. There is a constant demand for our graduates. We cannot supply them rapidly enough. Many of them are accepted even before they complete their training. This unusual demand for “Columbia” Trained Men is explained by the fact that our students enter upon actual drawing work the day they receive their first lesson. They spend no time with unnecessary preparation or useless theory. : The Largest Institution Specializing in the Training of Draftsmen Teaches You Mechanical Drawing at Your Home This is the mechanical age in world history. The day of big opportunities for technically trained men is here. Especially is this true in the case of Draftsmen, on whom the mechanical industries of America and the entire world depend. On no one profession does the continued development of machinery so nearly center, With the training which we can give you at your home, your service will always be in demand, at a pre- mium, in this permanent, highly paid field.

Drawing Instruments Furnished . We supply our students with complete Send In the Coupon Today drawing equipment. A professional draw- It brings to you full particulars of our proposi- ing outfit 1S furnished. together with a tion Your future depends upon what you do ss »e , adi . : : ' now. We cannot begin to tell you here, in so few highest grade set of Drafting instruments wens. Of the wivantiers aad you wy thie for your permanent use. unusually practical course in up-to-date mechanical drawing If you are in earnest and desire to learn a big-paying profession, we urge you to act now by returning the following coupon We will imme- diately send you our book of information, ‘‘Your Future in Drafting.’’ which tells of our new method of teaching mechanical drawing and outlines our offer to you fully. No Previous Training Necessary As our students are put into actual practice at the beginning, they grasp the essentials of drawing quickly. The lessons supplied are thorough, clear, and easily understood even by those who have r oom me — SEND THIS COUPON TODAY —<-<-<<-=— had no previous technical training of any kind. | No previous experi- COLUMBIA SCHOOL of DRAFTING Dept. 1403, 14th and T. Sts., WASHINGTON, D. C. ence or special education is neces- sary. Without obligation to me, please send me your illustrated book on Drafting, telling how I can secure your complete home COLUMBIA SCHOOL study course and your help in securing a position a Draftsman. of DRAFTING

Name ine eee PeevETrer ee. frre Roy C. Claflin, President Dept. 1403, 14th and T Streets as WASHINGTON, D. C. PPE ; .. State.

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~ 99 Double Ration P. meridaoetertatenecnes * Thy Baby 99 Double Action D aval a volver Oe Sis sodd cothine email oles e \Gammurtooe

sore ver and light we . wits ith the essential feat- Kee nites and e A HANDSOME yo MOST EFFECTIVE WEAPON scall emp Be varie just as ew the mn servics r e he pe you, can bt buy. aid Know bow to Measures but and 6! use it, and there is no safer or better op 4% inches long le th is ly great feature is its -. —a young men ad ladies. The illustration gives an idea of its’ gopeprance. but it must be seen and used to be thoroughly appreciated. The nab Ds used is the tandard 22-calibre cartridge obtainable anywhere, The operation of the charging mechanism is cei well rapid and ab- solutely reliable; six wel aimed chow can in as The revolver is very well con sm dm with finest nick- el plated, Suted pied and cylinder,and it wolahe ¢ ~ t 41-20) price of voiver ts ts sonity = sent immediately b: i, po tpaid, receipt of amoun! Ap inany eceventont deren, If with Peart Handles add $2.75. Cartridges- express only - 0c per 100.

Revolver Catalog Free Blank Cartridge Pistel 222 Calibre Real Revolver Style This well made and effective Pistol § is modelled on the pattern of the latest type of Revolver, the appear- ance of which alone is e' h toscare a burglar, ‘while when loaded, it will robably p rove just as effective as revolver with real bullets, withou the anger to life. takes the standard .22 Calibre Blank Cartridges, that are obtainable mosteverywhere, Even the most timid woman can use it with perfect safety and crigtten 0 thief cad ye risk to herself_or one else. can Save ty: it lying yoy Uitpest the di anger attached to = evolvers arge numbers aroun uly. Ms ell made, nickel finish. hes OnLy 3 so ad etter make and supe hens ‘orS stpa foes ik raaeaeaies = cents per Eanied ve ome P.0. Box 782, CHICAGO prices \_ Wf * . 50c and Write for So $1. OO Catalog FREE. aid, ADDRESS ORDERS TO ILLINOIS “SPORTING GOODS Co, _| Dept.187—

air method is mak- ingmen RICH! Chas. om Evans, carpenter, . past 60, now MAKING $100.00 a week in shop hown here. Gibbard of Mich., age 62, learned TIRE SURGERY, has shop ‘in small town, writes: ‘*C sash receipts for May, June and July, week through the mail. Tubes 1920, $30,000 guaranteed. New, strictly fresh stock. is easy to learn. I will teach you in two weeks, Stock PriceofTires Tubes Stock PriceofTires Tubes Within thirty days you're started Binet to fortune. Car 30x3 ..$ 9.60..$1.90 324 ..17.10..$2.80 owners EVERYWHERE demand thi 3 NEW repair meth- 30x3"/, 11.40.. 1.95 33x44 ..17.60.. 3.00 d, as it DOURLES life of Tires. 2 million tires wear- ies ee ee 344 ..17.90.. 3.10 ingdown DAILY. ONE THOUSAND M ORE Tire Sur- 32x3/2.. 12.80.. 2.20 35:41...21.50.. 3.50 frosded beady. N can succeed 31x4 16.80.. 2.50 36x4'/2..23.40.. 3.80

Send No Money All brand new tires TOQ0"sexr wire excw rine WE SAVE YOU MONEY Thousands of Satisfied Users We sell one car load of tires a . It’sa erg! EASY step into automo- i that bas made men ri ‘ot $8,000.00 for Fleming, of New vithin years and ~ Be undreds of , . There’s money fn this business for YOU, Investigate! Get de- tails. Send coupon at once for the FREE book. Shipped same day as order is received ©. O. D. with privilege of examination. 5% Discount for cash with your order. Sent at our risk, not yours. Don’t buy used or the so-called double tread or sewed-on tireswhen you can buy brand new high-class, 7000 mile tire, with a written guarantee from usatsuchlowprices. Order at Once. ACKSON TIRE COMPANY

1006 Jackson Bivd. CHICAGO, ILL.

Haywood, Pres dTire & 1275 Ca my + lndianapo Dear Sir: Send full details of Tire urgery. as I want to get into big paying business quickiy Name. lis, ind.

zB min your stove Se 5 listantly THE OLIVER OIL-GAS BURNER Does away with coal and wood—cheaper. Makes your stove or range a as stove. Heat when you want it—not a minute longer than you need it. o fires to make. No ashes, dirt, smoke, odor, chopping, shoveling -- carrying coal or "wood. Saves hours of work: Makes your stove bake better, cleaner, pong ‘Thousands n use over 10 years. Doesn ’t change your stove, simply sits in fire box, easil slipped {n or out ebeckatats safe.

PATENTS TRADE-MARKS COPYRIGHTS Send for our free book of patent information

804 ft. hing Lasts lifetime.’ 18 different models. Makes its own gas Beale & Par F St., Was ington, D. C. from coal-oil (kerosene) at small cost. Gives even heat 16 S. Broad St., Philadelphia, Pa. instantly, much or little, by simply turning a valve. Saves money, time, labo or. Sold under as mon oer. -back guarantee--30-day trial. Write for literature and special Wesedestery price. BUILDING AND FLYING AN AEROPLANE By CHARLES B. HAYWARD. A practical handbook : : x covering the design, construction —_ {operation of aero- Oliver Oil-Gas Burner & Machine Co., planes and gliders. 150 pages. Price, Oldest, Largest Mfr's Oil-Gas Burners in World, Popular Science Monthly, 225 West joth , a= New York 2007-E Pine Street, ST.LOUIS, MO. AGENTS WANTED. BIG MONEY.

me Only $422 Puts this Handsome Adjusted Gold Watch into Your Pocket Here is the biggest watch value in all America. Use this hand- some, thin-model, high-grade Illinois gold watch while you pay for it in easy \ installments. NO RED TAPE, NO DELAY. ust send us $4.50 and we ‘ send you the watch—20-year, plain-polished Gold-filled case—21 Senate —Adjusted to Positions, Temperature, Itsochronism, 16 Size. 50 Send us only $4.50 and we will send $450 a ont you this beautiful watch, transporta- tion prepaid. We Guarantee every one of these watches for accuracy and durability—they are all scientifically adjusted, carefully tested and examined before leaving our establishment Others ask cash. We allow 10 months credit. Our Special Introductory Price Only $45.00. Send only $4.50. Pay balance $4.50a month for 9 months. Get this beautiful, accurate world-famous Illinois Watch. Free Colored De Luxe Catalog Soy25 oa et at our

EA AS YOU PAY ALWAYS - - ON TIME -

“ “a big variety. Write today to Dept. 471-K ear , A = se0,00 ~<a: 7” L.W.SWEET, Ine. po,27 2ussof Seat*’s,,, NEW YORK

108 Popular Science Monthly Gold-Plated Brooches Made from Beetles URING the summer months many vacationists make a hobby of col- lecting beetles and butterflies that they usually mount in fancy frames against a background of cotton. While this practice is quite interesting in itself, something more useful could be made of these speci- mens. One concern in New York gold- plates these beetles and solders pins to them, so that they may be used as necktie pins, brooches, cuff-links, earrings, or hat- pins, etc. The first thing to do after the beetle is caught is to place it in a bottle of cyanide. This will kill the insect immediately. It is taken out and placed on pasteboard to dry The drying process usually takes three or more days, according to the size of the bug.! Remove the beetle from the drying- board and tie a piece of cotton around it attached to a piece of glass. This latter is to act as a weight, as the beetle itself will float. Dip the beetle in a solution made up in the proportion of one ounce of silver nitrate to a gallon of water. It is taken out

Gold-plated beetles form attractive pins, brooches, and medallions after three minutes or more and the excess allowed to drain back into the silver-nitrate solution. It is dried by exposing it to a strong source of light. Procure a bell jar, such as is used by chemists, and hang the beetle from the top of the jar. In the bottom of the jar is placed a saucer containing a few pieces of ferrous sulphide; over this is poured some dilute sulphuric acid. Hydrogen sulphide is generated that converts the silver nitrate on the beetle to sulphide. The reason for this procedure is that the silver nitrate is affected by the plating solution (being solu- ble therein), whereas the silver sulphide is not so affected. After this process is finished, the beetle is given a slight rinse in distilled water and it is ready for the gold-plating solution. A simple and inexpensive gold-plating solu- tion consists of gold fulminate 27 gr., potassium cyanide 4 oz., and water 1 qt. Any piece of gold can be used as anode, but it must be perfectly clean. Wrap around the beetle a stout piece of copper wire, which forms the cathode and is placed in the gold-plating solution already described. The beetle remains in this for at least three hours. When the desired thickness of gold has been reached, the beetle is taken out and wiped dry with a piece of chamois and a pin is soldered to it. If the beetle happens to be quite large, a safety-pin will do. The soldering should preferably be done by 2 jeweler.—SAMUEL WEIN.

I . ~ ND + ot ot

Popular Science Monthly \lau

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ly | May, 1921 le FF An Electric Bell Tells when | ’ Baby Is Restless m' hy A \ OTHERS need have no fear of baby ol- q 4 crying itself sick unnoticed on the ty front porch or in the back yard, if a simple a = contrivance is attached to the carriage to Wh ia ce start a bell ringing as soon as the baby be- bd ng comes restless. ci- ; The contrivance consists of an impro- 66 One - d- vised electrical contact to be attached toa a bell circuit. The contact may be made to Pj 9 99 ie it iece. is Bt “CAUSE the collar le. button made of a single , is piece of metal wears longer. ry It is better value than the “ee button with separate base of that may wear and fall off. ie “PARKROGER 4 ITRIY IR. ACE i ABSOLUTELY ONE-PIECE up COLLAR BUTTONS rer ut are the only buttons made from a single piece of rolled gold plate When baby is restless, the movement of the carriage rings an electric bell poison the skin. gold on both sides. Positively no base to wear loose. Can't stain or And made in a variety of styles to fit every man’s needs or fancy. —_ the individual style of carriage, but the Guaranteed to satisfy or a new button free. Ask your haberdasher or writer made one which works very well. jeweler for PARKROGER. On a block of wood about 3 in. square attach a spring in spiral form, about 14 or PARKS BROS. & ROGERS, INC. 34 in. in diameter, to which is attached one PROVIDENCE, RHODE ISLAND. wire of the circuit. An appropriate hook or means of easily slipping this block on or off the carriage should also be provided. Then attach the other wire of the circuit by a wood screw and washer to an ordinary ws wooden clamp. The clamp is so placed as L a to come directly over the spiral spring and the slightest shake of the carriage will cause a contact between the washer on the clamp and the spiral, causing the bell to ring wherever desired.—J. J. GINSBERG. Makers of Parkroger ‘‘Jiffy Link’’ separable cuff buttons. Why Not Weave a Mat from ess That Old Tire? ate ya the country where the roads and foot- paths are sometimes muddy, a good foot : : by mat is needed for the front porch. The old aoe AY py = 4 [Op auto tire makes an excellent mat for clean- EMPL” te - ae aes “TL ©, e j Y is ing mud from the soles of shoes. On we As. a ft 45 _ i a | ‘ of The old casing, after being cut in two at 2% 7 Meas \ me the weakest point, is cut into strips about 14 2 | } . g ide | in. wide and as long as the sound part of wr : ate the tire will admit. All rubber that will for | adhere to the fabric is left on. A is : The base for the mat can be made from ‘ lu- theend of a pack- Wh fi ees STRIPS OF OLD TIRE ing-case or a piece Ly pay carrare “4 7 ie Se br Le Ride to and from workon point” ball bearing construc- : . an Iver Johnson Bicycle. tion, both cones on one axle, d it boards properly You'llfeelbetter,sleepbetter, always in alignment. Every A cleated together work better, and save money. bicycle guaranteed satisfac- u- will answer. The Iver Johnson Bicycle tory. gr., The strips are is built with truss-bridge Iver Johnson Truss-Bridge qt. nailed tothe edge — —— hie “ Roadster Bicycle, $60. Other but igh carbon nickel steel; models, $47.50 to $75. (No “WOODEN PLANK pe hy il drop-forged parts; two-piece extra peed rge rocco vial Twisted strips of an ms. ha ta crank set; and new “two- Brake.) dis | old tire make a mat and nailed to the Write today for free Bicycle Catalog B ” Illustrated book- ady othe edge. Ifthe let on Iver Johnson Firearms “A” also sent if requested for strips are twisted about three turns as Iver Johnson’s Arms & Cycle Works, 343 River St., Fitchburg, Mass. 1871-1921 they are brought over the face of the base- 99 Chambers Street, New York 717 Market Street, San Francisco ( Plt has board, the mat will be more satisfactory. — and Spaces of 14 to 34 in. should be left be- a pin tween strips. Where the strips lie flat on The Iver Johnson is ; to the baseboard, nails should be driven | ee ms or an The through and clinched on the other side. If | cambine accuracy and Tics one ya 3 strips are not twisted, they should be ae ‘wr Quick ys om nailed about every 4 in.—E. E. LAMB. i 109 7] \fan. 192]

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HIGH SCHOOL COURSE IN TWO YEARS You Want to Earn Big Money! Ard you will not be satisfied unless you earn steady promotion. But are you prepared for the job ahead of you? Do you measure up to the standard that insures success? For a more responsible position a fairly good education is necessary. To write a sensible business letter, to prepare estimates, to figure cost and to com- pute interest, you must havea certain amount of preparation, All this you must be able to do before you will earn promotion,

Many business houses hire no men whose general knowledge is not equal to a high school course. ? Because big business refuses to burden itself with men who are barred from promotion by the lack of elementary education, Can You Qualify for a Better Position? We have aplan whereby youcan. We can give you a complete but simplified high school course in two years, giving you all the essentials that form the foundation of practical business. It will prepare _you to hold your own_where competition is keen and exacting. Donot doubt your ability, but make up your mind to it and you will soon have the requirements that will I Bring you success and big money. YOU CAN DO IT. Let us show you how to get on the road to success. It will not cost you a single working hour. We are so sure of being able to help you that we will cheerfully return to you, at the end of ten lessons, every cent ou sent usif you are not absolutely satisfied. hat fairer offer can we make you? Write today. It costs you nothing but a stamp. AMERICAN SCHOOL wooo H-575, Drexel Ave. & 58th St., Chicago z C.D CED O CEED © GED © HED © CHIDO Ga. intron School! Dept. H-575, Chicago, Itt. y Explain how I can qualify for position hehe @ ...... Architect #5,000t015,000) ...... Lawyer $5,000 to $15,000© Buildin Contractor wanned Mechanical Engineer 000 to $10,000 84,000 to $10,000 w... Automobile e Engineer Shop Superia hale aa ° A nee @3,000 to $7,000 ° ernses Avtomobiie R As § 500 to $4,000)...... ~ Enon cd er x § 09

- orga Civil Engineer $16,000! . 0 $10, to ..Ste eoeeed Structural Engineer = Engineer $4,000 6 000 to $10,000 Foreman’s Pye ere ‘den ager |” $2,000 to 4,000 © Certified "Ad muy ssid Sanitary Engineer - s,000ff tant _cogntant $7,000 po = seeeee Telephone Ener ° 500 to $7, 0 $5,000 wisi Draftsman & Designer Pees . han $2,500 to $4, ,000 $2,500 to $5,000 = Electrical Engineer: -+ High School Graduate & °. 000 to $10,000 In two years @ evveed General Rapeotion .....Kire Insurance Expert | In one year $3,000 to $ eats © Name. Address....

Has Your Circular Saw a Safety Strip? spite of the fact that state laws require, and factory rules compel, the use of safety devices on all dangerous machinery, workmen are still losing fingers and hands because they will not use the guards that are provided for their own protection. The usua! reason given for not using these guards is that they are in the way, and that they require time to adjust. Especially is this true in the case of a saw bench or circular saw, where a great per- centage of accidents happen when the operator is cutting narrow strips. Then the guide is so close to the saw that it is impossible to hold the strip safely with the fingers; and an ordinary stick or board will not do the double duty of pushing and holding down at the same time. A thin piece of basswood or some other tough, fibrous wood, cut as shown in the diagram, will give the workman a chance

$ BASSWOOD

A work7 | Many a finger will be saved if the sawyer uses this safety device to cut very narrow strips without endan- gering his fingers in the least. And this safety pusher is not in the way; neither does it require time to adjust. The hooked portion prevents slipping, while the end puts pressure downward; and the shape permits a firm hold above the guide.—ARTHUR M. HAHN. Endow Typewriter Ribbons with Longer Life RIBBON will give trebled service if renewed occasionally in the following manner: Into a small bottle pour about a tea- spoonful of light machine-oil. Then add the same quantity of ink. The ink used for stencil duplicating devices is the best be- cause it does not dry rapidly. Pour in 2 teaspoonfuls of gasoline or alcohol and then shake the bottle to mix the contents. To renew the ribbon, apply this mixture with a small brush to the ribbon as it moves through the machine. The ribbon can be turned from one spool to the other with one hand and the fluid brushed on it with the other without disturbing the typewriter. This is best done at night. The ribbon should then be tightly rolled on the spool, so that the fluid will be evenly distributed, and left till.morning. The oil is used in the renewing fluid to “moisten” the ink stil in the ribbon and, as it will not evaporate, it serves to keep the ribbon in good condition. The ink used tends to brighten up the color and strengthen the print. The gasoline or alcohol is used to dilute the mixture so that it can be brushed on easily and also tends to more evenly distribute the ink remaining in the ribbon. It evaporates soon after it is applied, but accomplishes its purpose. 110

Popular Science Monthly GMILLIONS $ IN PRoFITs HAVE BEEN MADE BY INVESTORS IN LISTED STocks YOU-CAN-LEARN their-METHODS-8e SYSTEMS Havent you noticed the fact that weolthy people seemed mare successfull in there investments, than others? There is a ‘Reason for their Success und it les in their Know lege of the principles, governing the profi tale trade wm Stocks and secu vee. \€-You- ) yoU can invest even a Smal . with as much Chance of profit asa milbonaive. f have gathered together the rules and systems used by the experienced traders in S@curities. ‘These I nave Sumpletied aud condensed into aseries of books, Covering a Course jn investment, They mean Bic Prorits “You ! Write Now! for Free Particulars INVESTORS PUBLICATIONS Ca

561 Spitzer Bldg. Toledo O.

RUBBER FIDE S E TREAD we } nary of high grade re- mstructed tii Built for 6,000 Miles wd eg All with genuine Goodyear Miller and Firestone new Treads bought direct from the fac- tory at smashed ces. Do not confuse these standard high grade mew tread tires with sewed or patched ones. Our speCial high pressure steam curing , Process gives new long mileage service and new appearance. SEND NO MONEY 1 un’, only after examination at express office. wrapped section for ins fter ex- mination, if you are not fully

tremen: 1s bargain vale wretern ship- ment and we will refund your money.

x 14.25 34x4% 14.75 35x4% 15.60 36x4% 16.25 33x5S 16.75 35x5 17.50 37x58 17.75 Stent ard-Make Taube WITH EAC yirite Laue f HUDSON TIRE CORPORATION Peoria and Harrison Sts. 141-4 Chicago, tll.

AUTOMOBILE BOOKS AUTOMOBILE REPAIRING Made Easy. By Victor W. PAGE. A thoroughly practical book contain- ing complete directions for making repairs to all parts of the motor car mechanism. 1,056 pp. Price, $4.00 DYKE’S AUTOMOBILE AND Gasoline Engine Encyclopedia. The most complete automobile instruction book on the market. It not only gives diagrams, trouble charts, etc., but enables you to instantly locate the particular trouble on hand. Also a complete treatise on _ trucks tractors, motorcycles, airplane en, gines, including the Liberty engine- (Parcel Post weight, 5 Ibs.) 95. pages—over 3,000 illus. Price, $6.46 Motor Annual Back Numbers Fully illustrated handbooks of new accessories for Motor Vehi- cles, of devices for decreasing cost of operation and increasing eff- ciency, and of practical ideas for the owner, dealer and repairman, com- piled from the PoPpULAR SCIENCE MONTHLY. Motor Annual, 1918, Motor Annual, 1919, Motor Annual, 1920, QO JC JC DW W bo mmm

Popular Science Monthly 225 West 39th Street | New York City

\lay;

—— saa? — 2085 2

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May, 1921 Learn to Dance at Home Lecrn all the new steps. Equip yourself with the finest of social graces. This wonderful new Movie method of Dance Instruction simplifies and makes instantly clear every aspect of the Dancing Art. It comes to you from America’s foremost authority on Ballroom Dancing, the in- structor who has successfully taught thousands in person and by mail. Let him teach you. The Good Dancer is Always Welcome Social life revolves around the graceful swaying of laughing, joyous couples lilting through the modern dances. And if you are correctly taught, the art of dancing is easily and quickly acquired in your own home. Sample Lesson 25 Cents Just to give you an idea of how remarkable and practical and simple this New Method is. Ad- ditional lessons $.50. Send $.25 for sample lesson today—and learn how easily you can master the art of fine dancing. A. M. SYSTEM OF DANCING Dept. 45 290 Broadway, New York

AUTO OWNERS Save half of your tire cost by using Double-Mileage, Double-Tread Tires, Guaranteed 6000 Miles. We lead, others try to follow.

Ys) They are reconstructed of highest 4) grade material — hardly ever blow s4) out. They are only guaranteed for id 6000 miles, but have run from 8000 to 10,000 miles. Order today at these low prices: eo A Me p10. nei

SCAND HERERAEABENE

; mT

j Size Tires Tubes is 66.50 Soe $1.60 el | DH " 6.75... "1185 Sgiiz .. 9.00... .. 2.00 Saee? . 8.00... .. 2.25 = Sic — ee .. 2.40 = icy . 8.50... , 2:50 ic = .. 2.60 23; -..» 10.00 3.00 ss -.. 11.00. 3.15 ED) eae 3.40 ~ 7x5 12.75 3.75

RELINER FREE WITH EVERY TIRE Send $2.00 deposit with each tire ordered, balance C. 0. D. Tires shipped subject to your examination. State whether S. S. or Cl., plain or non-skid is desired. All same rice. By sending full amount with order you can save E per cent—our special cash-with-order discount. DOUBLE MILEAGE TIRE & RUBBER CO. 3245 Ogden Ave., Dept. 102, CHICAGO, ILL. Deafness wt Perfect heating is now being re- MA Stored in every condition of deaf- ness or defective hearing from * causes such as Catarrhal Deaf- ness, Relaxed or Sunken Drum Thickened Drums, Roaring and. sx Hissing Sounds, | Perforated, ga Wholly or Partially Destroyea Pass 2 Drums,Discharge from Ears, etc. Wilson Common-Sense Ear Drums ‘Little Wireless Phones for the Ears’’ require no medicine but effectively replace what is lacking or defectivein the natural ear drums. They are simple devices, which the wearer easily fits into the ears where they are invisible. Soft, safe and comfortable. Write today for our 168 page FREE book on DEAF- NESS, giving you full particulars and testimonials. WILSON EAR DRUM CO., Incorporated 673 Inter-Southern Bldg. LOUISVILLE, KY. eT ee eee eee Standard Underwoods 5-Year Guarantee

much less than factory price, yours for$3.0)down monthly payments. 10 Days FREE Trial Try it for 10 days at our risk. & first slipping a J paper card on the How a substitute ‘Screw to prevent screw was made the solder running on the thread while soldering, the screw being held by a pair of pliers during the sol- dering.—JAMES M. KANE. 111

Extra Money and a Bigger Job Ahead He lives in Maryland and he is just one of thou- | et ey sands of enthusiastic United Y. School students. Though he has not yet completed his home study Course in Accountancy, he says ‘‘What I have already learned has made it possible for me to earn quite a bit of extra money auditing books for local business concerns outside of my regular hours. So of course I am enthusiastic.” This young man had been devoting spare hours to his home-study course considerably less than a year. Yet he is already reaping a return, and there is a bigger usefulness immediately ahead of him. His case is just one of many examples of the value of the United Y. M. C. A. Courses. These Courses are of the most concise and practical nature, built to meet the needs of ambitious young men who have only spare hours for study. Often the special knowl- edge that they afford enables a student to earn enough money while studying his course to pay its full cost. And this may prove true, whether the course is drawing, designing, management, foremanship, advertising, electrical: or mechanical engineering, core respondence, salesmanship, etc. The United Y. M. C. A. spare-hour courses are the result of many years experience in helping ambitious young men to put more into their heads. Last year the Schools aided more than 107,000 young men to increase their ability. Now, with correspondence instruction added to day and evening classss, the Schools have facilities to help many more thousands. The United Y. M. C. A. Courses are offered at most reasonable prices. Our platform is “‘the most service for the least money.’ Our earnest instructors are glad to hear from and to help every ambitious man.

The list below suggests only a few of the more than 200 courses. Check the subject that interests you most and learn how you can use spare hours to qualify yourself to earn extra money, to prepare for more congenial work, to qualify for a bigger job, to grow to bigger manhood and to assume larger re- sponsibility. It costs nothing to get this information and it may prove a real turning point in your life. The demand today is for trained men—for special ability. Pre- pare to meet the demand. Send This Inquiry Coupon UNITED Y. M. C. A. SCHOOLS Dept. 8MY 375 Lexington Ave., New York City I am interested in the position or home-study course I have marked. Please give full information Salesman Bookkeeper Stenographer Civil Engineer Business Law Surveyor Better Letters Electrical Engineer Business English Electrician Factory Management Steam Engineer Foremanship Machine-Shop Practice Mechanical Engineer Plumber Draftsman Farm Motor Mechanic Illustrator Architect Advertising Building Contractor Accountant Agricultural Courses Auto Mechank Poultry Husbandry Radio Operator Mathematical Courses Concrete Engineer English Courses Banking Foreign Languages Man

Addre

Learn About the Y.M.C. A. Standards in Correspondence Instruction

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ORGET ~ your ' pedals. Attach ly powerful, compact : ROLLAWAY _ to ™ your bicycle. Ride in comfort—any- where —up hill — through traffic— across country. Come home rested, refreshed and invigorated. ROLLAWAY gives positive, dependable power. Balances _per- fectly over front wheel. Weighs less than 25 pounds. Runs 100 to 150 miles on gallon of gas.

= LESSthan one-fifth cent per mile to operate. It’s a wonder for low cost, economy and pertormance. Learn more about this splendid motor. Be Our Salesman We want representa Send for circulars.

tive in yo 4 ROLLAWAY ells on sight. Cyclists amazed Easy spare time work. Big ommissions pac Few hours’ work quickly pays for your m r Wr NOW for exclusive terri- tory Send AT ONCE for splendid proposition The Rollaway Co. 513 Shepard St. TOLEDO, OHIO TRADE MARK

ONARG Are Found Wherever Lathes Are Used Schools and Colleges use them for 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 improve ments'and 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 Ifst. Schools write for our special school proposition The Monarch Machine Tool Co. 116 Oak Street Sidney Ohio

Popular Science Monthly Adapting a Small Lathe for Shaping By H. H. Parker WELL known lathe stunt is the cutting of a keyway by placing the shaft between centers, setting the tool upon its side in the toolpost and then moving the carriage back and forth by hand, feeding the tool in a little after each cut. This is a slow and inefficient method, but the prin- ciple is capable of being elaborated by the addition of a few attachments that will convert a small lathe into a hand-power shaper able to handle a large variety of light work. The application to a medium or large-sized lathe would be hardly ih, practicable, unless int a special light car- riage was built, for the regular carriage, MARDWOOD

so that the tool cannot be fed in beyond this depth. The mandrel must be capable of rotation by hand between cuts, but during the cutting it is clamped by a steady rest or other means. The tool being set in a tooth space of the master gear, it is withdrawn by means of the cross feed and then gradually fed in while taking a cut on the blank; if the mandrel is securely held, the whole depth can be cut until the stop is reached, without injuring the master gear. Then the tool is set at the next tooth space and so on until all the teeth are cut. ee By removing the a cross-feed screw and reversing the wood block, facing the

being rather heavy, would require most of the muscular power of the opera- tor to move it back and forth. The illustrations

Jj? m BACK i CARRIAGE BOLTS, “PLAT E <_ Nam.)

lever around parallel to the lathe-bed, as indicated by the dotted lines in the illustration, a trans- verse motion of the tool-block instead

show a hand lever as fitted to an old 10-in. Barnes lathe, but no dimensions are given, for these, of the carriage may be obtained, for end shaping of work held in the faceplate, though in this case

as well as construc- the link stud must

tional details, would differ with every make of lathe. An oak plank is mor- tised to fit over the lathe-bed and clamped to it by means of two iron or steel plates, one of which is removable; the sleeve being used only to bring the clamping-nut within convenient reach under the bed. A long iron or steel lever is pivoted at the rear end of the oak plank and at about 12 in. from the fulcrum a short link is bolted which in turn connects with a stud bolted to the carriage. Two or more links, of different lengths, may be provided for work requiring short or long strokes. If possible, the carriage hand wheel or ‘handle and pinion should be removed, as the device will then be easier to operate. The work is held between centers and the tool upon its side in the tool- post, as de- seribed above, the feed being given through the cross-feed handle. Gears and ratchets — suffi-

ae: rath é=.

ciently accu- || Sos «(CON rate for many _ || =e purposes, may Vaal be cut without a special index by mounting a master gear of the same diameter and number of teeth as the one to be cut, on a mandrel beside the blank. A tool is shaped to fit as accurately as possible in the tooth space of the master gear, while in the tcolpost and while in this position, a stop is placed on the tool slide 112

This attachment to the lathe will cut keyways as well as gears and ratchets with sufficient accuracy

be attached to the tool- block instead of the carriage. A small shaper head, built with a shank to he clamped into the tailstock barrel, will further increase the usefulness of the lathe-shaper equipment. In using this device, the work would be clamped to the tool-block and moved back and forth under the shaper tool, the latter being provided with a vertical slide similar to that found on a regular large shaper. The _ illustration shows a miniature shaper head built up without castings, with a vertical move- ment of about 1 in.; a small clapper block relieves the tool on the reverse stroke. If possible to remove the key in the tailstock barrel, the shaper head may be rotated to any angle. A further ad- dition would be an angle plate or column to bolt to the tool-block, sim-

Other attachments that will increase the usefulness of your lathe for shaping are here illustrated ilar to the lathe milling attach- ments. This would be pro- vided with a vertical slide of substantial construction ]

that would earry the shank of the shaper head just de- scribed. Such a device would allow the work to be held be- tween centers on the faceplate, on a small table or vise bolted to the lathe-bed, or to the lower portion of the tailstock if of the “‘set-over’’ pattern, the barrel being re- moved. The latter forms a most conveni- ent table for clamps or a small vise.

duc’ suck evel grol T ins pose sun thes ver} are A or ! soil dry chic tiliz put the its ¢ V plac hav be | T evel plac foor soil are are 60 po) le an thi

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~ wm & ct > eB ae TS a mo. ws S- 1e id Ly id ld e, se st ne id to er ch Id ye- all to May, 1921 Water-Lily Culture for the Garden ie is curious that the culture of the water- lily has only recently begun, considering what a wealth of material this beautiful vegetation offers. With the introduction ff the Victoria regia the cultivation of water-lilies had an added impetus. The need of planting our lakes and ponds with aquatic flowers other than the white lily spurred gardeners to attempt the pro- duction of flowers with variegated colors such as red, blue, and yellow. 'Now every year brings new varieties to the fore- ground. These ornamental flowers are cultivated in small ponds especially dug for this pur- pose or in barrels sawed in half and then sunk into the soil of the garden. Under these conditions water-lilies will develop very satisfactorily if the proper varieties are chosen. All water-lilies, whether they be tropical or native, require a heavy rich soil. Sod soil is to be recommended when clay and dry cow manure is added. Guano or chicken manure is the best possible fer- tilizer for barrel culture. The fertilizer is put into the barrel and then spread before the soil is put in. This will aid the plant in its development. Weak plants or rootstocks should not be placed in deep water. After the plants have become stronger, the water level may be raised. Tropical water-lilies should be replanted every year, especially when they are placed in barrels, for their demand on the food supply has made the soil barren. The soil should have a depth of approximately Even a small lily-pond will add an attractive touch to your back yard 6 to 8 in. and should be regulated by the thickness of the rootstocks to be placed in it. The water should have, after planting, a depth of 4 in., later twice or four times as much. It should not be forgotten that the majority of water-lilies bloom less in deep water than in shallow water. The overwintering of the tropical varie- ties takes place through the development of bulbs in contrast to the northern varie- ties, which produce rhizomes. In their natural habitat water-lilies live through the dry season in this state. When the bulbs form, one must be careful to see that they are.fully developed. About October they are taken out of the soil, the leaves are re- moved, and the longer roots cut off. They are kept dry for nearly a week, then they are washed and placed in water of about 60° F. Winter-hardy plants can be kept in the pond or other container if it has a sufficient depth to prevent the frost from penetrating and killing the plants. Water-lilies kept in barrels must be placed in frost-free places for the winter months. In May, at which time the plants awake to a new life, they are again brought out.—E. BADE. 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 afternoon. 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 mont! 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 wy $55.00 TO $300.00 WEEKLY . | selling the Speederator. Best article to advertise itself you ever saw. Once ona 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. ey Ariz., 72 in two weeks—$216.00 clear. Join the ranks of successful men in this work. NO EXPERIENCE NECESSARY Just show us that you mean business and are ready for business and we will show you how. But first, make us 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 bus; now. Write to-day for the necessary information and see for yourself. Don’t delay—plenty of good territory left—if you area hustler you can have money in the bank THE GREATEST FORD INVENTION in a few weeks. ust write—-now—to THE PERRIN METAL PARTS CO. 1094 Hayward Building, Detroit, Michigan SHEET A manual of practical self- C A R H E-; N | R z instruction in the art of pattern drafting and con- By GILBERT TOWNSEND, S.B. ener mal a A practical treatise for the use of carpenters ing skylights and roofing, and woodworkers on simple building con- cornice work, etc. struction, including framing, root constru 272 pp. 370 illus. tion, general carpentry work, and exterior WORK Price, postpaid, $2.60 and interior finish of buildings. 258 pp., > 368 ills. . 9 Popular Science Price, $2.10 Monthly POPULAR SCIENCE MONTHLY W. Neubecker 225 West 39th Stret, New York 225 West 39th Street, New York ave /2 on (oncreteMixer Load on one side and unload on the other. Easiest tomove. Lightest. Simply built---'4 less parts. No exposed worting parte. Shaft revolves in bath o oil.{Does or of $500 mixers. Perfect mix. Mixes over 3% cu. ft. batch in less than a minute. Great labor 6aver and money maker. «OT TAW, Concrete Mixer 30 DAYS TRIAL--10 Year Guarantee, Backed by largest Log Saw and Engine factory in the world. It must make good. Cash, or easy payments, aes BOOK, show- san power or hand mixers our lowest prices on request. Get them to- ag. Know these prices ore you choose eny concrete mixer. TTAWA MFG. CO. Unless OFT Stone Street * KANSAS L Autos & Fa $100 to $400 earn Tractors rn Per Month Sots cad Rte Retneeslek ana bright totarein he truction, you can learn to operate, adj east and repair -all makes of Truc 5 ned Autos, Tractors, cks and Gas Engines. cluding. complete automotive electricity. w tuition now. work with actual tools. rite at once for particulars A fine Kit of 29 tools given to eryo ho enrolis now. 'Se ee book. Get full informaiton, MILWAUKEE MOTOR SCHOOL, Dept.3 105 555 Downer Ave., Milwaukee, Wisconsin ide aRané¢er g thefinest bicycle Sciscth built any w my reat ead ot oe — 44 heey ts SAVE ‘sit to $25 $2, Zour were, onthe to n. int for r bicy: oy iat = Companyitis | elie enieage eS Ove 8 the Other OTTAWA ; FOR 8000 MILES SERVICE and guaranteed against defects for 5000 miles. Not a Sewed, Patched or Retreaded Tire—but a sturdy fabric casing rebuilt of new materials, which we are confident will give mileage equivalent to a cord tire. Standard non-skid, geared-to-the-road tread, of new live rubber same as drawing. * A Brand New Tube berg hey Ramen Tire Ordered—Good Tires backed by real ‘uarantees cannot be sold any cheaper. ° 28x3 - $7.30 31x4 $10.95 32x4% $12.55 36x44 $14 50 Bees e O40 32x4 11.30 33x4% 13. 35x5. 15.59 3. 37x5 . 15.60 init i 30x34 .. : 9.10 33x4 11.75 34x4% 1: 32x3% SS.only 9.70 34x4 11.95 35x4% 1406 } State SS. or y. Aa SEND YOUR ORDER TODAY with $2.00 Sj) deposit. Tire shipped balance C.O.D., with section left unwrapped for examination. If not satisfactory, deposit will be returned’in 1. = FIELD TIRE & RUBBER CO., Dept. 191, 28th & Wabash Av., Chicago i) Jonnie oucn

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4 ’ 7 BS meds heey OneMan Saws 40 Cords aDay i

At a Cost of 1c a Cord! Send today for Big Special Offer and Low Direct Price on the OTTAWA, the One- Man Saw, the first made and sold direct from factory touser. Greatest laborsaver | 4 H-P. and money-maker ever invented. Saws | needed. OTTAWA [OG SAW Cuts Down Trees—Saws Logs By Power Patent Applied For —

any size log at the rate of a foot a minute. Does the work of moved from log to log or cut tocut as any wheelbarrow. gine has balanced crank shaft—pulls over Magneto equipped; no batteries

NAY ie snr! of0GU = Fi) Sa SNe Cuts Down Trees Level with Ground Leaving No Stump. ten men. As easily 4-Cycle Frost Proof En-

; jever controll- Special Clutch of ch abics you tostartand stop saw with en- ginerunning. Automatic Speed Governor. Easy to move, costs less to operate. When not saw- ing, engine runs_pumps, feed

‘ mills and other machinery. Pulley furnished. =e Cash or Easy Payments Shipped direct

Write at once for . Free Book and Low Price. for itself as you use it. See the OTTAWA at work on your farm once and you will never give it up. Thousands in use, every owner a booster market, Send today for FREE BOOK and Special Offer. ? OTTAWA MFG. CO., 1805 Wood St., Ottawa, Kans. from factory. e ‘\30 Days Trial No waiting—no delay. Lett — LA OTTA

Asaw yourlogsandpay 10-YEAR GUARANTEE. . Out-saws any other on the

TAKES THE IRE OUT OF TIRED TT X10 high a stand very quickly puts an ache in arms and shoulders. A low stand develops stiff 1 between the shoulder blades. KS and pains

Tired typists are cross, make costly mistakes, cre- te office friction. With the “Satellite’’ Adjustable Typewriter stand, each typist works with machine at exactly orrect i Hours of maximum efficiency are prolonged. Time savings as high as 20% reported by users of ‘Satellite’ stands—better work, more of it, finished in less time. CONSTRUCTION : Cast metal base large, noiseless casters con- ains accurately machined screw column on which is set the new metal adjustable top. Elevating hand wheel quickly sets top at any desired height. Correct design gives a solid, substantial table, light in weight and easily portable. This attractive effi- cient equipment pays foritself quickly. Aliso ethcient for adding and billing ma- chines, auto- graphic registers and other me- chanical office- equipment. Some Prominent Users : Larkin Co. (612 stands) Pennsylvania R. R. Standard Oil Co White Motor Co. Illinois Steel Co J. P. Morgan & Co General Electric Co

Lukens Iron & Steel Co Dayton Laboratories Corp. and thousands of oth: rs.

Sold on 30 days free tria See it. use it, then judge for your- self. Write today for prices, illustra- ted literature and complete informa tion ADJUSTABLE TABLE COMPANY Dept. G. Grand Rapid, Mich.

((heapest Way to Go: : to work, to school, or for fun and recreation is on a Ranger Bicycle. Choice cf 44 Styles, colors and sizes, fave 610 to #25 on Dinect From-the- Factory shipment. 30 Days Free Trial, shipped on approval. We pay the express both ways if not accepted. on installme AQMonthstoPay i t des eae Saved time and carfare easily meets the small monthly payments. Parts equipment—half usual retail prices, 7 I r es Send no money. Write for big, illustrs Cycle Company {°°."4"2 Mead &'5.: Chiago frees sft N

Tapes and Rules ACCURATE ASK YOUR DEALER Send to us for Catalog No. 12

SAGINAW MICH.

in the-.center. Around. to the btdy screws. Popular Science Monthly Make an Attractive Lamp for His Den i iver body of this lamp is made of four 14-in. boards fastened together to form a tube 7 in. square at the base and 5 in. at the top. sOpenings are cut in the boards for lighting the lamp and to add to its beauty The square opening at the top is covered with/a lid that has a hole 2 in. in diamete: It is marked C in Fig. 3 2 top, fasten plain molding, B. The ' --- is made of four strips joined a: in Fig. 4 * The strips forming it are screwec with round-headed brass T: > shade supports, Fig. 5, aré

Price $6.00 Value of Drawing Instruments $25.00. Special offer to advertise. Write for FREE catalogue.

| GOLDEN GATE COMPANY, 4331 North Oakley Ave., Chicago, Il. FOR’ ALL PURPOSES STANDARD MANUFACTURERS NEW MOTORS oe": ALL SIZES UP TO 5SH.P. We Specia!ize In Small Motors & Generators ALL PHASES AND FREQUENCIES IN STOCK AT ALL TIMES IVE Me Orde? Sma | Motor talk Largest excl

YA HP bycinty (i ha Special Quartity Prices Write For Latnlog.

inthe world. CHAS. H. JOHNSTON, Box EZ}, West End, Pittsburgh,Pa.

within the range of the home worker BOOK DEPARTMENT

Popular Science Monthly, 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 Price, postpaid $1.00 225 West 39th Street, New York

How to Run a Lathe An 80- page book for 10c Postpaid, Coin or Stamps

Established 1906 SOUTH

OD” Bimtiee... isc. Sa” Eiaties...... SOUTH BEND LATHES For the Machine and Repair Shop REDUCED PRICES seseen $215.00 03° Cimthee .. ....0 0 0<0e. Sees See! Oe SS ree $450.00 ol eee $525.00 South Bend Lathesare made in eight sizes, 9-in. to 24-in. swing inclusive. Free Catalog BEND LATHE WORKS 433 MADISON STREET, SOUTH BEND, IND.

Why not make an ornamental lamp? Here is how it can be done

also screwed in place. The shade frame is made of oxidized copper strips averaging 2 in. in width. The inside ends are bent into hook form to receive and hold the art- glass filling. Figure 6 is a section of the side. The copper strips are riveted together, and when the work is completed, should be nicely lacquered.—T. ADLER. A Very Simple Way to Lock a Nut - replacing a bolt on a piece of machin- ery, it was desired to provide some means of locking the nut in place. The bolt was not long enough to allow the use of the ordinary lock washer, and on account of clearances it was impossible to use a longer bolt. The improvised washer shown in the illustration was used with good results. Aeross the bot- tom face of the nut, a slot was filed aboyt 3/16 in. deep. -The surface against which the nut<fitted was treated in a similar way, the slot being chipped to about the same depth. A washer was’ cut from light sheet metal to fit the’ bolt, its outside djameter the same as the distance across corners on the nut. Theenut was tightened in the usual way. The metal of the washer was then forced into the grooves with a small punch. The nut was locked securely from turn- ing either way and proved entirely satis-

Ore of the simplest ways of locking anut

114 factory.—L. R. BUTCHER.

all AS al: cle pr tu K

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ww e is ring vent art- the her, d be yck hin- ome The » use ount se a lown ition rith bot- the filed in. rface 1 the was milar t the from , its tance ; was tal of oOVves turn- satis- May, 1921 y because we secured ar en “ous lot of Qaly Men’s Fine Dress Shirts from su. overstocked manufacturer can we offer them at-+this amazingly low price. _We claim this great bargain cannot be | matched anywhere in America. And to prove it we sindly send them to you without one pee in advance, After ongentantion if you’re not convinced —don’t take them. It won’t cost you a cent tosee for : yourself that this is a world beating Send No Money! Made of finely woven Supertex Percale in the ate. Bee pany i. in smartest colors. Cut extra i Rin coat ~— Double soft French Cuffs. Pearl fal in Exe lently made in every detail, they have a snappy. dressy, appearance and give splendid wear. H guaranteed fast. Why pay $3. 00 each for such shirts pg you can get afer postage on arrival? i Just send your name, cag ark and neckband ef size for three of these wonderful Dress Shirts. Pay only $3.43 and val, our ee low price for Bd —— only. Your money back if you are not. fect! Sizes 14 to 17 neckland. STATE YOUR SIZE. | OAVID STRONG COMPANY Dept. W1095 Chicago 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 Circular-Saw Attachment for Bench-Grinder HE sketch shows a useful attachment for a small hand-power bench-grinder that converts it to a hand-power circular saw and the home mechanic will soon find many uses for one. The grinding wheel is removed and a small saw clamped in its place; usually a packing collar will be required to make up for the narrow width of the saw. A saw- -table is made up of steel or iron plate about )% in. thick, or, lacking this, a maple or other hardwood board will answer the purpose. This table is made tilting by screwing two legs at its rear end and a slotted bracket at the front end. The bracket is bolted, with a thumb-nut, to the grinding-rest bracket provided with the grinder. As the legs rest directly upon the bench, to allow for any unevenness of its surface, a cap screw is screwed into the lower end of each leg and to obviate the use of locknuts, the legs are split and pressed together before inserting the cap screws. They will then enter tightly and will not work loose. For light sawing, this being all that the attachment is designed for, the table will be firm enough, though if thought necessary, the legs could be attached to two small angle brackets screwed to the bench, thus anchoring the table at three points. A guide-plate, preferably with an angular as well as a parallel adjustment, will be GU! DE-PLATE TILTING — GUIDE- GUIDE-PLATE, \ TABLE ) PLATE \ BRACKET ADJUSTING SCREW ADJUSTING y BRACKET SLOTS FOR ANGULAR G SPLI ADJUSTMENT OF GUIDE-PLATE ee Cee = =F =F ScREWFOR | ¥ ADJUSTMENT tf _ BOLT GUIDE - Cold Pipe Bending Machines Standard of the World Bends all sizes 4% of pipe from Le in. to 8 in. Hand or mo- Models tor operated. E&F Send for Catalog Standard Pipe Bends 1” to 6” pipe, in stock for immediate delivery. AMERICAN P:PE BENDING MACHINE CO. 51 Pearl Street BOSTON, MASS. =PROTECT GOOD TOOLS= Good tools deserve a Union Chest. ™ Styles and sizes forall mechanics. mM Quartered Oak, Plain Oak and Covered. Write for catalog and prices. UNION TOOL CHEST CO., Ino 24 Mill St., Rochester, N. Y. G13) Smgl] Cash Payment Starts You Making Big Profits Charging Batteries BUY YOUR HB CHARGER NOW Just a little cash brings you a money-making HB outfit—almost a year to pay balance on easy monthly § terms. Sizes for 10, 16, 32 or 70 batteries. Money- back guarantee. Write for information on size you need. HOBART BROTHERS COMPANY, Box S 57, Troy, Ohio You Can Clear s150 to 5300 a Month capacity.—H. H. PARKER. ———=/ PLATE HERE o a LEG 7 SAW TABLE aw Ror STeEt PLATE ———) 5 GUIDE-PLATE BRACKET If you have a hand-power bench- grinder, you may easily convert it toa circular saw for small work needed, and an easily constructed one is shown. The plate itself is of steel or hard wood and is held vertically by means of two brackets bolted to it. The long horizontal bracket arms are slotted so that the guide- plate may be slid along the table axially with the saw and clamped in any position. To allow of angular adjustment, two slots are also cut in the saw-table through which the bracket bolts extend. These allow of the table’s being shifted around at an angle with the saw. Another way to rotate the guide-table would be to remove the bolt from one bracket and allow the table to swing on the other as a pivot. As but one bolt and a thumb-nut are needed to attach the saw-table to the grinder and one more nut to clamp the saw in place, it will be seen that the attachment may be quickly set in place and removed, and for intermittent, light, accurate sawing, such a device is much simpler and more compact than a power-saw of greater 115 The Logic of Williams’ Superior Drop-Forged Tools BETTER TOOLS MAKE BETTER WORKMEN BETTER WORKMEN increase PRODUCTION INCREASED PRODUCTION lowers COSTS LOWERED COSTS increase PROFITS There are no better tools WILLIAMS’ than HENCE TOOLS PROFITS WILLIAMS’ INCREASE Williams’ Superior standard lines of Drop-Forgings and Drop- fully described in books, any of request: stock Forged Tools are the following which will be sent on Drop-Forged Wrenches Wrench Sets Machinists’ Lathe Dogs Clamps Tools Caliper Gauges Tool Holders Pipe Wrenches and Vises J.H. WILLIAMS & CO. “The Drop-Forging People” BROOKLYN BUFFALO CHICAGO 7 RicHAarDS St. 7 VuLcAN St. 1007 W. 120TH Sr. St. Catharines, Ont., Canada DROP-FORGINGS often cheaper than castings —always far superior—

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Veeder Trip Cyclo meter, having extra dial which sets back to sero, to indicate mile- age made on each oh f in addition to total. Price, $3.00. Raceiili the Miles for the Bicyclist The ‘bike’ equipped with a Veeder makes a_ record of miles you ride. You watch it register as you ride—reading the distance you put behind you—getting a record to show for your trip. ROR CYCLOMETERS were as universally favored by bi- cyclists of 25 years ago, as they’re esteemed by the younger generation today. Thousands of men have the name “Veeder” stamped on the memories of their boyhood, by the little instrument that registered their ability to “‘cover the miles.” Illustrated at left is the regular model cyclometer for bicycles—familiar the world over. The instru- ment is dust and water- proof; has no spring in the mechanism; cannot “‘skip”’ or register too much. The figures are large and close to the dial—easy reading from the saddle. Regis- ters up to 10,000 miles by tenths of a mile, then repeats. Price, $2.00. Veeder Cyclometers include models especially made for motorcycles; built stronger than the regular bicycle cyclometer, and designed to withstand the vibration and shocks of high-speed motorcycling. Price, $3.50 and (Harley-Davidson model) $4.00. A little booklet giving all the points and illustrating all the models of Veeder cyclometers, 1s free for the asking. You may also like a copy of the Veeder Counter booklet, showing counting mechanisms for other than bicycle purposes. The Veeder Mfg. Co., 44 Sargeant St., Hartford, Conn. HE cost of getting photo prints made continues to rise, encouraging the ama- teur to do his own printing. With the ordinary printing-frame this is a slow process; by using some form of box printer the time is greatly reduced, but not every one has the ten dollars or more to spare for such a device. The writer, finding himself in just that position, got together a collection of odds and ends, and made the printing-box shown in the illustration. As will be seen in Fig. 1, an old packing- box was the starting-point in the con- struction. A piece of glass was found just wide enough to fit in the groove in which the sliding lid works. Strips of black paper taken from a printing-paper package were pasted to the glass so as to form a mask. Several of these masks, of any desired size and shape, can readily be made if one has some pieces of picture glass and a cutter, but only one, of course, is necessary for one size of camera. The glass mask is inserted as shown, and the box-lid is brought up against it; this prevents all light from getting out of the box, so that unused paper can be kept at hand, uncovered, while printing. Two electric lights are required, taking current from the 110- or 32-volt house- lighting system. The printing is done by an ordinary 25-watt clear tungsten lamp aor a edit W ates Here the homemade photo-printing box is shown with the glass slide open to disclose the printing-frame placed directly under the glass; in Fig 2 a tubular lamp is shown, but there is no necessity for using this particular shape. To the right is the second lamp, which is to serve as a red light to assist in placing the film and paper for printing. If one cares to expend seventy-five cents for a standard ruby lamp, it will be a little more convenient, but the writer uses an ordinary 25-watt lamp with two thicknesses of red ribbon around it, and finds it entirely satisfactory. The keyless socket for the ruby lamp is held loosely in place by catching the cord leading to it in a screw hook; a staple would do just as well. A key socket is used for the printing-lamp, and is fitted snugly into a hole cut in the end of the box. The hole should be located at a distance of 4 to 8 in. from the top of the box, depend- ing upon the size of the pictures to be made. The center of the filament should come under the center of the open space in the mask. The socket should be placed, and the mask made, with this condition in view. The two sockets are connected, in parallel, to a cord running to an attach- ment plug. While using the outfit, the ruby lamp remains lighted continuously; when a film is ready for printing, the key ll Popular Science Monthl, Build Your Own Photo-Printing Outfit By Curtis Ralston socket is turned on for the required number of seconds. For holding the paper and film agains the mask, one may use the back of printing-frame, if it is of the right size, « an old bath-towel, rolled up evenly an fastened with a safety-pin or two, pressed firmly against the glass, holding t} print and film in close contact. The rig! hand holds this pad, while the left operates the printing-lamp key socket. In the box illustrated, the filament about 41% in. from the glass, and th: average time required for printing is abou 3 seconds. Four or five prints can be ex- The printing-box open to show the arrangement of the two lamps, one a safe light, the other for printing posed every minute. For timing prints, probably the handiest way, in the absence of a metronome or other timing device, is to count “‘thousand and one, thousand and two,” ete.; by comparing your counting with the second-hand of a watch, you can easily learn to count seconds in this way. Certain precautions must be observed. If the box is small, and the lamps are left on very long, the wood will get very hot For the sake of safety an asbestos lining may be used. The ruby light should b« turned off now and then while getting films and paper ready for printing. Keeping the Mud Out of the Bearings LAD who twice daily supplied the people in his neighborhood with news- papers found that the mud and water that worked into the bearings of his bicycle wheels soon wore them down to such an extent that they needed new cones and balls. To protect his wheels he cut washers of soft felt and fitted them over the bolt that runs through the axle of the wheels as shown. These washers were so soft that they in no way impaired the efficiency of the wheel, yet they were absorbent enough to take up ' what water and soft mud ran dow! the spokes. Once a month o! so, the washers were removed an: washed out, an again put on. The illustration show the washers at- tached to the hu! of the front wheel Felt washers will keep water and mud out of bicycle bearings May, ] C |= rol made- rolling cones | angle ( rately leavin; form ¢ two di procee boards V groc Tos hill, be end of higher Of ¢ the lay the up As the suppol line Al ts £ ~, FIG.1. Thi: but slopes of the the cor lower |] The determ most fF some o handy, by qu ing the anythi eter, h on the the dis found » other. necessé¢ length, sides rr where | eter of other e cone to TI MM’ belts e belts u that be conditi That used. Same ir a belt because affectec cement laundri IS satur Popular Science Month; May, .

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; May, 1921 How to Construct a Climbing-Cone Puzzle T= mechanical illusion known as a rolling or climbing cone can easily be made by any one possessing a lathe. The rolling body, Fig. 1, is a double cone (two cones base to base), with sides forming an angle of 45 degrees. This should be accu- rately turned froma piece of hard wood, leaving a pin projecting at each end to form an axle. The cone is placed across two diverging boards, Fig. 2, and at once proceeds to roll along the edges of the boards until the ends of the axle drop into V grooves cut to receive them. To all appearances the cone is rolling up- hill, because it starts at the narrow, lower end of the boards and rolls to the wide and higher end. Of course, the wooden cone really obeys the law of gravitation like everything else, the upward movement being quite illusory. As the cone rolls along the edges of the supporting boards the axle moves along the line AB, Fig. 2, and as will be seen, this line e FIG.be FIG.3 d This double cone seems to roll uphill, but that is only an illusion slopes downward toward the diverging end . of the boards. So the center of gravity of t the cone is really moving from a higher toa " lower level all the time. g The size of the double cone will naturally e determine all the other dimensions, and as g most people will probably make this from some odd piece of wood that happens to be handy, no useful purpose would be served by quoting exact measurements. Assum- ing the cone to have been made, and to be anything between 3 in. and 1 ft. in diam- eter, hold two laths in a slanting position m on the table, varying the gradient and also "i the distance between them until the cone is t found to travel easily from one end to the i. other. Then get some one to make the n necessary measurements as to _ height, d length, and distance of separation. The sides must be as far apart at the wide end, f where the notches are made, as the diam- t eter of the cone, and close enough at the e other end for the thick middle part of the cone to rest upon their edges.—H. T. GRAY. n There Are Steam-Proof f Belt Cements S MANY engineers are firmly of the opinion that lacing must be u8ed on belts exposed to steam, as, for instance, belts used on pulleys in laundries, etc.; that belt cement will not hold under such conditions. That all depends on the kind of cement used. Not all belt cements are made of the Same ingredients. Steam will not dissolve a belt cement made on a pyroxylin base because it is waterproof, therefore it is not affected by moisture. The use of such ’ cement is strongly advisable in dye-houses, ] laundries, and other places in which the air is saturated with steam. May, 1921 40 Years of Progress with Fine Tools -all Richmond turned out.” When America’s first electric trolley cars were run in the streets of Rich- mond, Va., in 1887, the whole city turned out to watch them. Even then, when electric cars were the newest sensation, machinists had already learned that the rame of Starrett on a tool meant unfailing accuracy and long service. The highly-skilled mechanics who build the electrical machinery of today know that they can depend upon Starrett Tools—on the Star- rett standard of precision that never varies. 2100 fine tools—with forty years of “know- ing how” behind them—are described in the Starrett Catalog No. 22“W.” Write for a copy. It’s free. THE L. S. STARRETT COMPANY The World's Greatest Toolmakers Manufacturers of Hack Saws Unexcelled ATHOL, MASS. : Immediate shipment Booklet describing on request. Dept. A, Pilliod TOOL CASES EXCEL Machinists, Tool Makers and Carpenters find them most satisfactory in construction, appearance, service and price. 20 styles The Pilliod Lumber Co. FINLAY Swanton, Ohio Electrical and Mechanical Engineers receive fabu lous salaries Thousands wanted 3 months to 2 years. Practical-Technical training under experts Not a'‘trade school but a Practical-Technical College teaching electrieity, steam, gas, auto-electric, armature winding, drafting Extensive laboratory and shop equipment. Dewrees awarded Day and night sessions Enroll any time. Don't judge us by size of ad Write for free catalog =a I EERING COLLEGE, 1002 Indiana Ave, Kansas City, Mo LATEST OUT. =Log and Tree Saw Now. you’can get the latest WITTE Arm Swing, Lever Controlled, Force Feed Log Saw for sawing up logs any size. Movés like a wheelbarrow—goes any- where—saws up-hill, down-fill or on level. Cuts much faster than former rigs. Oper- ated by a high power, frost~ -proof WITTE 4-Cycle Engine Costs only 25 to50 cents a day to oper- ate. Double the powerneeded for saw- ing logs ortrees. Perfectly balanced rig- Can be used for belt work. New WITTE Tree Saw At low cost additional you can now get the new WITTE Tree Saw Equipment — changes Log Saw to Tree Saw. Saws down trees any size Send ay Log and Tree Saw Gutetes. oi this Complete Log Saw O. B. Kansas City, Mo. ees Pitteboron Pa., add $6.80 Don’t buy any Log Saw, Tree Saw or Buzz Saw Outfit until you have seen the new WITTE. Lowest priced Guaranteed rig on the market. Cuts much faster than for- mer rigs. On tests we cut 2-ft. log in 90 seconds. Treesaw cuts ’em close to the ground. Goes anywhere. We are making a special earertetes: price NOW—So write at once for complete description of _ wonderful outfit FREE. BRANCH BUZZ SAW $23.5 WITTE Engine Works 2226 Oakland Ave., Kansas City, Mo. 2226 Empire Bidg.. Pitsburgh, Pa. . ea ge ur

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Is Yours a Quality Kit? The progress you make in the shop is de- pendent on the qual- ity of work you turn out. High quality work calls for high quality tools. Good Work Means Advancement Therefore see that the tools you purchase are accurate, durable and of known relia- bility. Good tools are a worth-while invest- ment. Brown & Sharpe Tools are designed by men who have studied your requirements— practical men who have anticipated your most exacting de- mands. Brown & Sharpe tools are good tools. Catalog No. 28 describes our complete line of machinists’ tools. You'll also find many pages of useful information for daily reference. Sen? for your copy today Brown & Sharpe Mfg. Co. PROVIDENCE, R. 1, U. S. A. Popular Science Month; Removing Gears with a Puller ELOW are illustrations that show the construction of a device which will be found useful around the small shop or garage for pulling gears, pulleys, or collars off shafting and a variety of similar work. The body of the puller is made of a piece of square cold-rolled steel, drilled for the clamp-screw bushing and slotted as well as drilled for various sorts of pulling arms. As there would be considerable wear in the threads of this kind of a fitting, a removable nut of bronze or gun metal is shown, being made a drive fit into the body and held by a small set screw. In case the bushing wears, it may be driven out and a new one substituted. The screw has a square head for a wrench and it would be well to harden the head as well as the point. Sometimes the point will bear directly upon the work; at other times a thrust block interposed would be best. Two types of thrust blocks are shown, one with a flat face, either roughened or smooth, and one with a V-groove for bear- ing against curved surfaces. The small DST oc CLAMP SCREW - BUSHING Pi fe CHAIN PULLER PLAIN THRUST BLOCK’ © — ' ! ' i 4 ' ' ' tr ee a i i. rast deck PLATE FOR DRAWING PULLEY OFF SHAFT, ETC. MAKE IN PAIRS Jiggs for removing gears, pulleys, or collars from shafting ends of the thrust blocks are drilled to take the end of the screw and are slit in four places with a hacksaw. A groove is turned just above the point of the screw and the slit ends of the thrust block slightly bent in so that it will spring over the screw point. The pulling arms are made in pairs; one form is a plain hooked type filed from flat bar steel with the upper end drilled for a pin. Another kind is a hook bolt, the nut and washer bearing upon the top surface of the body and the bolt extending through the groove. Such arms may be adjusted for unequal lengths, if required. Another form is the plain eye-bolt; either the eye is held by a pin through one of the drilled holes in the body, the bolt extending through the part to be drawn off and secured by nut and washer, or the bolt may be reversed, the eye being secured to the work and the nut bearing upon the body as in the case of the hook bolt. Sometimes a couple of chains are more convenient than solid arms; the upper links may be held to the body by pins or by eye-bolts. Chains are adapted to irregular shaped work or for pulling a part at some 118 distance from the clamp screw. A ste] plate yoke frequently is useful, especially the center is drilled for slipping over a shat: and the arms are drilled for the bolts ser -- ing as pulling arms. Such a yoke may slipped behind a pulley or gear and the pa°t removed without danger of damage t} might occur if the arms were attach: directly to the rim. Another illustration shows a pair clamp blocks and two bolts serving as ar: —_ — = ct = 72 CLAMP SCREW oe L SLIDING BLOCK SECTION AB -— EE My PULLING MAGNETO BALL RACES '] TEEL CLAMP BLOCK “OR bres es = TYPES OF PULLER ARMS CLAMPING BLOCKS This clamp-block is very useful for pulling ball races from magneto shafts and attached to the clamp screw block. One block slides and is drilled for a bearing to take the end of the screw; the other is drilled and tapped for the arms. Work is clamped between the fixed and sliding block. To conclude, a small fitting is shown that has proved very convenient for pull- ing the ball races from magneto shafts. It is in two parts, bolted together and bored out to take the race, over which it is clamped while the puller arms fit into the end notches. Such races are difficult to remove, with- out injury, unless some special fixture of this sort is used.—H. H. PARKER. A Dust-Cap to Protect the Machine-Oil Hole | Ieveseriadengde! that is to be operated in locations where much dust prevails should have the oiling holes well protected from the outside air. This is generally pro- vided for, but in the case of farm machin- ery the manufacturers sometimes overlook the importance of this item. Following is a simple cap that can be quickly fashioned out of materials usually lying about any machine-shop or farm work- bench. Cut enough round disks of stiff leather to cover the re- quired number of oiling holes. Have them large enough so they lap well over the edges—about | in. in diameter, if possible. Punch a sma! hole in the center of each one. Now take as many small cotter-pins as necessary and cut them off so that whe thrust through the caps, the ends of their tines will not quite touch the shafting i the bearing. With small pliers, bow t!: tines outward as shown. They will then OIL HOLE The cap keeps dirt out of the oil hole have to be forced gently into the hoe and will successfully hold the cap down in place.—L. B. ROBBINS. May, J rr HE | is W the sun in this 1 water, © culatior By a boots iz in comf all the they Ww from tk The by mez tending makes of a flu side an strip tc there is no mat agent. The feet fre Esté rubl swung strikes course proces well as Var AS that vy aroun especi and f¢ the he bits, i cover. until requir Sure 1 remov be asc thick so tha it whe from 1 to coo put t with benzo Wh which off th impu These bottle Popular Science Monthly Popula

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ied oa May, 1921 Air Currents Dry Wet Boots Quickly T= great drying agent of the universe is warm air in circulation. Of course the sun and a hot stove may heat air and so in this way indirectly aid the absorption of water, but it is the dry, warm air in cir- culation that really does the work. By a most simple process I can dry wet boots in half an hour so they may be worn in comfort, and in a few hours I can take all the moisture from the wettest boots so they will be as dry as the day they came from the store. The photograph shows how this is done by means of a strip of roofing-paper ex- tending down inside each boot leg. This makes of the inside of the boot something of a flue and the air current goes down one side and comes up the other. Without this strip to partition the boot into two parts, there is no circulation of air, and dead air, no matter how warm, is never a good drying agent. The boots should be hung three or four feet from the ground, where they may be Our New Trade Mark! STANLEY Establish air circulation in your wet rubber boots and they soon will be dry swung a bit by the wind and where the sun strikes down upon them to heat the air. Of course a slight breeze aids in the drying process. Strips of wood or bark will doas well as the roofing-paper.—F. E. BRIMMER. Varnish Made from Hard- Rubber Waste GOOD flexible varnish can be made out of wasted bits of vulcanized rubber that will come in handy for general use around the home and workshop. It is especially valuable in waterproofing shoes, and for cementing patches on automobile tires and worn rubbers. To make it, proceed as follows: Place the hard rubber pieces, broken into small bits, in an iron pot that closes well with a cover. Put the utensil on a hot coal fire until the rubber is melted, which will require about five or ten minutes. Make sure that every piece is melted before removing the pot from the fire. This can be ascertained by stirring the mass with a thick wire. Next grease a sheet of metal so that the molten rubber will not stick to it when cold. Then take the melted rubber from the fire and pour it on the metal plate to cool. Break up the mass into pieces and put them into a bottle, filling the latter with either rectified oil of turpentine or benzol. When the mass is completely dissolved, which may be accelerated by shaking, pour of the solution carefully so as to avoid the impurities always found in hard rubber. er usually settle to the bottom of the ottle. 4 Danvlar Serence Monthly Good Carpentry Begins With Good Tools Stanley Carpenters’ Tools are the world’s standard—the best, and, therefore, the cheapest tools you can buy Stanley Carpenters’ Tools are preferred not only in the workshops of the world, but in the Manual Training Schools and in the homes as well. Always ask for Stanley Tools, and be sure you get them. Look for the Trademark Write for Catalog 7E THE STANLEY Rute & LEVEL PLANT. THe STANLEY Works 4 New Britain, Conn. U.S.A. Wy Xs Vee 5 N WG — | SOX \ > AX 119 RedDevit | & REG.U.S. PAT. OFF, That’s all you need to know about a plier This is your assurance that each tool is made as well as care, experience, finish and the best workmanship can make it. Each tool drop forged of tool steel—scientific- ally designed—individually tempered and tested. “Red Devil” Pliers are high quality tools, not high priced. Look for the trade mark on each and every one—it’s worth your while. Red Devil/ 16 Bar nee Slip-Joint Plier No. 1024 The right pair of pliers for household repairs, for wiring up the engine, and for light work of all kinds. Handles fit the hand without pinching— the thin nose fits in tight places. Beautifullv nickel plated. At all good hardware dealers, or if not, send $1.10 for ‘“‘Red Devil’’ Plier No. 1024—6% inch. size. WRITE TODAY FOR FREE TOOL BOOKLET SMITH & HEMENWAY CO., Inc. Manufacturers of ‘‘Red Devil’’ Tools 264 Broadway, - - - New York, N. Y. ‘“*Red Devil’? Glass Cutters are made in 40 styles—the glaziers’ standard tools of the world.

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Reg.U.S.Pat. Off. ““As hard as fire and water can make them”’ —The Disston file-maker Disston makes between sixteen and eighteen million files a year. Some weigh a tiny fraction of an ounce. Others 135 Ibs. Some are for a lady’s fingernails. Some for gigantic chunks of steel. The supreme test of a good file is in filing the teeth of saws—steel cutting steel. And nearly a half-million Disston Files are used yearly in making Disston Saws—“‘the saws most carpenters use.” No wonder Disston Files eat through the work in quick time! No wonder the experienced filer enjoys the feel of a Disston File as it bites into the toughest metal! Disston Files are Disston-made from the steel to the packing case. They are of good, true steel, “as hard as fire and water can make them.” Send for new free booklet, “The File in History.” HENRY DISSTON & SONS, INC. Philadelphia, U.S.A. Popular Science Monthly A List of What Disston Makes And in these Saws, Tools and Files is that quality found in “The Saw Most Carpenters Use" Back Saws Band Saws for Wood and Metal Bevels Buck Saws Butcher Saws and Blades 404 Circular Saws for Wood, Metal, and Slate Compass Saws Cross-cut Saws and Tools Cylinder Saws Drag Saw Blades Files and Rasps Grooving Saws Gauges—Carpenters’ Marking, etc. Hack Saw Blades Hack Saw Frames Hand, Panel, and Rip Saws Hedge Shears Ice Saws / Inserted Tooth ‘ Circular Saws Keyhole Saws Kitchen Saws Knives—Cane, Corn, Hedge Knives—Circular—for Cork, Cloth, Leather, Paper, etc. Knives— Machine Levels—Carpenters’ and Masons’ a a IMianarels Milling Saws for Metal ca? Mitre-box Saws Mitre Rods One-man Cross-cut Saws Plumbs and Levels Plumbers’ Saws Pruning Saws Re-saws Saw Clamps and Filing Guides Saw Gummers Saw-sets Saw Screws Screw Drivers Screw-slotting Saws Segment Saws Shingle Saws Slate Saws—Circular Squares—Try and Mitre Stave Saws Sugar Beet Knives Swages Tools for Repairing Saws Tool Steel Trowels—Brick, Plastering, Pointing, etc. Veneering Saws Webs—Turning and Felloe This is a partial list. There are thousands of items in the complete Disston line. DISSTON SAWS TOOLS FILES) | Popular ’

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Popular Science Monthly ak ai) Uae Ve

The Victrola is to music what gold is to commerce —the one final standard of value. When, in selecting an instrument for your home, you choose the Victrola and Victor records, the whole world confirms your judgment. Victor records and Victor in- struments are one. Each is made to operate with the other and no | other combination can be made to : | produce as satisfactory results. .

This trademark and the trademarked word ‘‘Victrola’’ identify all our products. Look under the lid! Look on the label! Victor Talking Machine Co. VICTOR TALKING MACHINE CO. Camden, N. J. Camden, N. J.

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ae fe PAG tion Popular Science Month/, Popular Science Monthly JUNE, 1921 Volume 98-No.6 Important to Readers Owing to the paper short- age, the number of printed copies of POPULAR SCIENCE MONTHLY is limited. To insure getting your maga- zine regularly, you should place a standing order with your newsdealer, or send us your yearly subscription of $3.00. CONTENTS AERONAUTICS News by Parachute : Straight Up from the Ground Air-Travel Rates Ten Years’ Airplane Development Shooting Ducks from an Airplane Airplanes Guided by Undersea Cable Caproni’s Transatlantic Flying-Ship FOR THE FARMER Spraying the Chicken-Coops for Mites Rock and Keep Cool Pareeeen cae ako Comb the Cranberry Bushes............... 4. Sieve on the End of a Hose.. Killing the Flea-Beetle ste wie es Ice Bought by Slot-Machine...... Fattening Chickens by Machine........... Electricity to Keep Milk Fresh. . Water “Pumped” with Endless Belt he Foreign Crops in the United States........ Sheep Haul Farm Produce Sie tag Imitating the Spider's Web to Catch Flies. .. Weeds and the Law Blankets Protect Alfalfa... . This Little Pig Went to Market . Seed-Sower Like a Hand Organ............ Chicken Farming by Electricity........ Fertilizing Air with Carbonic-Acid Gas Right and Wrong in Strawberry Picking... . Eggs Dipped in Boiling Oil Keeps Them Fresh Beans Four Feet Long } Give the Lawn a Clean Edge. Quicklime for Dynamite. . Pe eee Warming the Water for Tropical Lilies. .... A Simple Seed-Corn Tester The Corral Travels with the Animals (Continued on page 4) 2 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 tlie 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 permis 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 is sh tricks butts to do. Thi able in six numb amou time. tractc quart less t doing Th ured “pull’ tractc effort the w itself, of th This to on drawl to 3§