Popular Science Monthly 1919-09: Vol 95 Iss 3

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SEPTEMBER

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i GREAT! You'll Say It Is! The New “TEA FOIL” Package! It’s soft and pliable— decreases in size as the tobacco is used'—;tobacco does not cake in the package —no digging it out with the finger. Keeps the tobacco in even better condition than tin. Now, don’t youowe it to yourself to, buy a pack- 3 age and'give Tuxedo a gy trial? — Not quite as much tobacco as in 4 the tin, but— t AN WT? Pe al eS 1 = (Jas ' o @ : \a | fe) a —[———————— 7 = = = — " TVTTIVTTTT TT T QE WAY — the lightest, thinnest, finest, strongest cigarette papers in all the world. Roll a Tuxedo cigarette with RIZ LA CROIX. Finest Burley Tobacco Mellow-aged till perfect Plus a dash of Chocolate J f NoseKnows The Perfect Tobacco for Pipe and Cigarette Guaranteed by te Masvisan {INCORPORATED i

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Popular Science Monthly Waldemar Kaempffert, Editor September, 1919; Vol. 95, No. 3 Twenty Cents; Two Dollars a Year Published in New York City at 225 West Thirty-ninth Street Changing the Course of a River A powerful dredge that sucks |} up the bottom of the sea [J] tie tow of a river the rise and fall of the tides, to project itself to a depth of forty-three feet, and to raise one thousand cubic yards. of clay an hour. The clay is not dumped into a well in the ship, but is carried off through a second pipe, twenty-eight inches in diameter and fifteen hundred feet long, to some point on shore. One triple-expansion engine of 725. horsepower drives the pump and the ship’s propellers. She has a speed of nine knots, and is one of the few suction dredges that is self-propelling. Besides the triple-expansion engine, there is the auxiliary compound engine of 175 horsepower for turning the cutter, and an auxiliary compound engine of 80 horsepower for working the winches. Built in Holland The ship has two cylindrical boilers, each of thirteen hundred square feet heating surface and a working pressure of one hundred and eighty pounds. The dredge was built in Holland for the Australian government, and will be used on Australian rivers; it iscalled the South Australian. The length of the dredge is one hundred and thirty-seven feet, six inches; the breadth, twenty - nine feet, six inch- the flow of a river as it follows its course,—all battling together beneath the surface,—con- stantly disturb a river-bed. Its soil is picked up, swept away, and dropped where the waters see fit. Where- upon man comes along with his dredge, gathers up the soil, and puts it back again. But sometimes changes are desired, as, for instance, when the channel must be deepened. When the Soil Is Soft When the soil that is to be dug up is soft, a suction dredge is generally employed to do the work. A pipe is lowered until it touches bottom. Then a pump, which is attached to the upper end of the pipe, is started. The soft soil is sucked up and dumped into a well within the ship. Later it is carted away. / The dredge on this page is a H// suction dredge, but it is constructed J to suck up hard, stiff clay—a very unusual combina- tion. The pinwheel- shaped cutter at the bow of the _ ship makes this possible. The cutter is at- tached to a shaft that runs up through the suction- pipe. When the pipe f is lowered into the water, the whirling cutter first plows up the clay, which the pipe then swallows. Eight Revolutions a Minute The cutter - head is composed of a set of hard cast- steel knives, and is turned at the rate of eight: revolutions a minute by.a 175- horsepower com- pound engine. It is possible for the pipe The pinwheel-shaped cutter at the dredge’s bow chops up the hard clay of the ocean bed, which the suction pipe then swallows with ease 17 es; depth, eleven feet, six inches. When the dredge was tested she ex- ceeded all expecta- tions. Instead of raising one thou- sand cubic yards of stiff clay in an hour, she raised eleven hundred and twenty-nine cubic yards. And when she was put to work where there was a sandy bottom she sucked up twenty- six hundred tons an hour.

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parninnepipiicanaandas - recorder. Popular Science Monthly \A ARS A * ANXAACAAS RS ee oe ee By turning a fly-wheel a boy can move this greenhouse from plants that no longer need shelter to those that do What—a Traveling Greenhouse? IKE a setting hen that will move from nest to nest when each batch of eggs is hatched, there is now a greenhouse that will move from bed to bed when eath batch of plants no longer needs protection. Of course it doesn’t move of its own accord; but, although it weighs twenty tons, it can be moved by a small boy. In fact, the same small boy can r =e it even when it is weighted down wth an ad- ditional fifteen tons of m:--as the illustration above shows. The greenhouse is raised on wheels that run on tracks placed about six feet apart. To move it the boy turns OR ee Nese WX \ ; * a wheel. Inside the greenhouse are pipes and a boiler for heating it, a cold water supply, a ventilat- ing gear, and every other green- house necessity. When it has sheltered one batch of plants until they are sufficiently strong to battle with the elements, the hinged eaves of the greenhouse are lifted up and fastened in place until the moving to a younger bed is finished. Thus it passes easily over the taller plants. This greenhouse measures one hun- dred feet, and it was invented by Mr. A. Pullen-Burry, of Worthing, England. Recording Both Sides of a Conversation N cases where important conversa- tions are carried on by business or professional men it is often desirable to preserve an authentic record. This has been made possible by the recent invention of an apparatus to be used in connection with an ordinary desk tele- phone and one of those phonographic recorders now extensively used for dictation. In the accompanying pic- ture the apparatus is enclosed in the neat case with the curved receiving horn. For direct dictation the per- son who is dictating speaks into the curved horn. The sound vibrations strike the telephone transmitter, which carries them to a highly sensitive magnetic When a telephone con- versation is to be recorded, the receiver of the tele- phone is placed on top of the case,.as shown in the picture. The weight of the receiver actuates a vibrations from the microphone of the receiver to reach the diaphragm of the transmitter within the apparatus, which in turn transmits it to the re- corder of the phonograph. In place of the regular receiver the person engaged in the conversation uses a watch-case receiver, which, when not in use, rests in a socket in the case. Salt Down Your Peas and Beans O you like sauerkraut? Then you will also like sour beans, peas, beet-tops, and many other vegetables. They may be kept in almost any kind of jug, jar, keg, or tub, for they need no air- tight lids. The souring of the vegetables is due to fermentation brought about by the action of salt. Tale Salt will preserve vegetables; a small amount causes fermentation, while large quantities keep the vegetables fresh string-beans, for instance. You lay a one-inch layer of beans on the bot- tom of a crock, then sprinkle it with salt. Put in another layer and sprinkle that with salt. Keep this up until your crock is three quarters full, using salt at the rate of three pounds to a hundred pounds ‘of beans. Cover the beans with cheesecloth; on top of the cheesecloth place a board and a stone to weight it down. The weight and the salt will extract the juice from the beans and form a brine in about twenty-four hours. Then the cheesecloth, board, and stone are removed, and fermen- tation begins. While it is go- ing on bubbles rise to the surface. As soon as these bubbles cease, the fer- mentation is complete and the crock should be removed to a cool place. To prevent mold, cover the beans with paraffine ' or oil. But suppose you don’t like that sauerkraut taste. Then preserve your beans with a large amount of lever which closes the in- side opening of the curved horn and allows the sound With this instrument interposed between your telephone and your dictation-recording phonograph, you can easily record both sides of a telephone conversation 18 salt or a very strong brine, and they will keep their natural flavor.

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September, 1919 Two Speeds for the Freezer a HAT are you running her in?” ‘“High,’’ comes f= the answer from behind the barn. You listen < for the purr of a motor, but you don’t hear any. Because the men are running, not an automobile, but an ice-cream freezer. Wade H. has invented an ice-cream freezer that, like a Ford, has two speeds, high and low. Asin the case of an automo- bile, high speed means that while very little power is used, and low speed means slow rotation at greater power. I means of two handles, one for each speed. But why should an ice-cream freezer need two speeds? “HIGH SPEED

ICE Gent FREEZER At high speed the shaft revolves rapidly, using little power, while low speed means slow ro- tation at greater power and offer little re- sistance to the re- volving blades. When the ice- cream _ thickens, more power is needed to turn

Why? Stemple, of West Virginia, the shaft revolves rapidly t is operated very simply by you ask. Compare its problems with those of an automobile. When freez- ing is started, the contents of the can are in liquid form

the shaft. Both of the hich gears may be used ried at the same time. This ice-cream freezer has two speeds, both gears can be worked at once Make Your Flashlight Batteries HOSE who have watched the growth of the flashlight industry for the past ten years have noticed two things in particular: the rapid transforming of this article from a novelty into an every-day necessity; and a growing and low, just as an automobile but the difference is, in the freezer SIDE PLATES. Section view of the appa- ratus for lowering the plate growl of discontent at some batteries on the part of the consumer as well as of the merchant. Heretofore you have n more than one battery at a time. For, by the time you were through using the first battery, the other one would have become almost exhausted. Now you can buy a set of six or more cells, and make up - your own batteries whenever a ‘ you care to doso. You can | 4 send a set to a friend in France or distant China, and he can make his own batteries when the package arrives. Full instructions accom- pany each battery set and it is easy to make any kind of battery by following them. It is in the perversity of things that batteries gen- erally give out when they are needed most. What a convenience it would be to be able to make one any time you needed it. ot been able to buy

Here is the complete set. The battery can be made and assembled in the space of just a few minutes. A simple mixing of chemicals is the secret of this very useful idea 19

Taking Bumps Out of Roads The T-bar by which the plate is lowered into place rests on forms in the road. The plate is attached by threaded nuts and moved up and down by thumb-nuts . ON’T take that road, it’s full of holes,” a fellow motorist tells you. Whereupon you ask your- self once again why a fairly new concrete road should have developed holes in so short a time. Perhaps some of them are due to the breaking of the concrete at the expan- sion joints. These joints are necessary —as in the case of railroad tracks—to allow for expansion in hot weather and contraction in cold. They are usually made by inserting thin boards along the road before the concrete is applied, and then pulling the boards out again after the concrete has hardened. But the sharp concrete edges break easily. To overcome this defect,’a new armor-plated expansion joint has been invented. The plate is made up of three parts: a thin central one ex- tending through to the bot- tom of the concrete, and two shorter, thicker ones at- tached to each side of the thin central one. All three are set flush with the top of the road. The outside plates have beveled edges to prevent chipping of the adjacent concrete. A strip is cut from each outside plate and bent back to pro- vide anchor arms. The plate is lowered into place by means of a T-shaped bar.

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Making Freight-Trains Do More Will the Bonner rail-wagon system solve the problem T is contended that our railroads are I today run on unsound economic principles. What are these unsound economic principles? you ask. Well, consider for a moment these few facts: That, whereas the average speed of a freight-train is twelve miles an hour, or two hundred and eighty-eight miles in twenty-four hours, the average freight-car mileage per car per day is only 23.7 miles. In other words, out of every twenty - four hours the average freight- ear is actually running only two hours. That the average earn- ing per freight-car per day is only three dollars and fourteen cents, not- withstanding that the charge of the average of freight hauls in the United States is seventy-five cents a ton for each hun- dred miles moved, with the capacity of the cars ranging from forty to sixty tons apiece. That the total freight revenue for 1918 of $2,869,446,322 was earned with freight-cars actually in motion only two hours out of a possible twenty- four, or only one twelfth of their earning capacity. The trouble seems to be that the railroads fur- : nish not only transportation but also warehouse facilities. The cars have become warehouses to all intents and purposes, because they stand still for twenty-two out of every twenty-four hours. This warehouse service chokes the railroad terminals; ties up freight- cars; cripples the system; and, finally, is the cause of the financial difficulties with which the roads are now con- fronted. From Producer to Warehouse The Bonner rail-wagon system of transportation, described on this and the opposite page, is of particular interest, since its adoption on a large scale would greatly reduce the idle freight-car time under the present-day methods. In brief, the Bonner system, invented and devéloped by Colonel Joseph P. Bonner, of Toledo, Ohio, offers a plan whereby freight of less than a carload may be moved direct from the point of origin to the destina- tion warehouse or wholesaler without rehandling! This seems impossible; but it has By Joseph Brinker been accomplished by the joint use of road vehicles and rail vehicles. The basic unit is a road van in which the freight will be loaded at the point of origin. This van closely resembles a large furniture van, but differs from it in that it has its four wheels sup- ported on side brackets instead of crosswise axles, so that the entire van, wheels and all, can be slid bodily on to a steam or electric railway-car Popular Science Monthly Work of freight-car congestion? so that when two or more units are mounted on a railway car, the doors may be swung outward to form an end-to-end vestibule, giving the ap- pearance of a continuous car body. Specially Designed Motor-Truck The fourth unit is a specially de- signed motor-truck provided with a low platform, upon which the entire van unit may be loaded by The confusion that is apparent to any observer in the neighborhood of city terminals contributes to the present serious freight-car congestion; the “‘rail-wagons” of the Jo- seph Bonner type suggest a possible solution of the problem chassis. Both the vans and the rail chassis cars are so designed that the mounting and dismounting of the units may be accomplished entirely by me- chanical means and in a minimum pe- riod of time. The van units or wagons are placed astride of the railway chassis car in- stead of on top of it, as is the usual method employed when moving cir- cuses from town to town. By reason of the special mounting of the van wheels on brackets instead of conven- tional crosswise axles, the wheels of the units overhang the sides of the railway car. The elevating and lower- ing of the van units is controlled en- tirely by the steam or electric railway train engineer through the use of air-jacks on the rail units and em- ploying the same air used for the air- brakes. Aside from the road van, there are two types of railway cars, one for steam railways and one for electric trolley lines. Each is capable of carry- ing two or four of the road-van units. Each of the van units is provided with outside doors at each end on both sides, 20 means of a sprocket-chain system operated by the truck’s own propelling en- gine. Similarly, the van unit may be unloaded by the truck engine’s power. Withthe physical equip- ment of the system thus outlined, let us assume a shipment of wheat origi- nating at a farm ten miles from the nearest electric railway. The farmer puts ina request for one or more empty van _ units. These are delivered to him by the electric rail- way company through the medium of the motor- truck unit of the system. The farmer loads and locks each van unit, and notifies the electric rail- way company that they are ready for movement. The farmer cen either drive them over the road to the railway tracks by teams of horses or preferably have them hauled on the special motor-trucks. Arriv- ing at the electric railway tracks, the van units are pulled over and on to the special electric railway car chassis without disturbing the load. The elec- tric railway then transports the loaded van units to the nearest steam railroad if the wheat is being shipped toa dis- tant point. Here they are again trans- ferred, this time to the steam railway car chassis. The van units are then hauled over the rails to the railway terminal, where the vans may be removed and unloaded or loaded on an electric car line, and finally on to the motor-truck for final delivery. The plan has great possibilities for eliminating the present terminal con- gestion. It is proposed to construct a terminal in the form of a great circu- lar platform with an open space in the center for street vehicles, and a re- volving turntable on the outer circum- ference on which the loaded or empty van units could be switched to the platform from the terminal yard tracks. pgpllicets

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September, 1919 ttt 7) eat EEE 1 itt} | ee fy 4s FREIGHT PLATFO | UE as TURN-=TABLE LOADING RAILS TURN- TABLE POWER*HOUSE ya 1 cee on ifaes! Ape! ft IEP ‘ - “ ee once rneee 7 — " BRIDGE E _ FREIGHT-HANDLING YARD _ FOR MOTOR-TRUCKS ETC. RM FOR; ROAD VANS SN TRUCK-LOADING? SKIDS AND. RAILS Circular Platform to Be Used in the Proposed Bonner Rail-Wagon System The platform shown above, which it is proposed to construct at railroad terminals for use in the Bonner rail-wagon system, would be approximately one hundred and fifty feet in diameter. A large open space in the center, reached by means of a bridge, would accommodate street vehicles, and a revolving turntable on the outer circumference would switch the van units of Mr. Bonner’s scheme from track to platform. Fifty wagons or motor-trucks at a time could back up to this platform. and de- ' posit their contents. Then, by revolving the turntable, the van units, backed up to the outer edge of the platform, could be brought to any outgoing freight deposited on the platform. The circular platform could easily be adapted to use as a market-place

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SS Sa He’s Making Sure to Give Full Measure HE smile on this orchard- ist’s face might be called the “‘full-measure smile.”’ The contraption con- nected with the handle is a press that is used to put all the apples possible into a barrel without making cider of them. The barrel is filled to overflowing, is placed on the bent lower ends of the iron side pieces, and pres- sure is applied until the head boards are in place. Carelessly packed apples are apt to bruise in shipping. Popular Science Monthly This Is How They Grow in Alaska GHOULD you meet the Wal- rus in Alaska, and should he start his favorite conversational topic, ““Cabbages and kings,” you can come right back at him with the remark: “I know little or nothing of kings; but, speaking of cabbages, did you know that H. O. Banta, just south of Skagway, raised two cabbages that weighed thirty pounds each?” Any United States citizen can have 160 acres of Alaskan land for home- stead purposes for the asking. ©Keystone Photo News Stand By to Pick Up the Mail Keg! I? is not unlikely that the Azores will be- come an important station for trans- atlantic air commerce; yet steamships hurrying across the water do not consider it worth while to put in there, not even at Fayal, and so a picturesque method of delivering mail has been devised. Letters for the islands are placed in a small keg, weighted so that one end, bear- ing a staff tipped with a bright-colored pennant, will stand upright in the water. As the ship nears one of the island ports, the deck officer sounds a long blast on the siren. At once small boats put off from shore. Overboard goes the mail keg, riding shoreward on the swell from the ship, and is picked up by the boatmen. This Tractor Rivals the Feats of Samson of Old \ N THEN Samson staggered off with the haul from the freight-yards to the plant of Its trip was not marred by a single gates of Gaza on his shoulders, the a shipbuilding company at Newburgh, accident, the tractor loafing along ahead multitude gasped. When a small cater- N.Y. The length of the haul was a little of its heavy burden with the tranquillity pillar tractor hauled a twenty-seven-ton more than an eighth of a mile, andthe of a turtle making its way toward a Diesel engine an eighth of a mile, it was engine was handled on greased skids with sun-kissed spot on a sandbar. the aid of triple blocks. considered a part of the day’s work. The Diesel engine was intended for in- stallation in a ship under construction. This necessitated a 2 OE WE: Ya B,_ The feat was not considered extraor- dinary, because a little while be- fore the same tractor had been used in moving a large piece of — d ship machinery weighing forty- bff seven tons.

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September, 1919 He’ll Soon Be Out of a Job ee eseD up in a_vestlike jacket and stowed away com- fortably enough on a little shelf just behind the pilot’s seat in the airplane, this homing pigeon was the aviator’s only means of send- ing word back to head quarters. On many occasions the pigeons carried appeals for help from men whose airplanes had fallen in the sea. The perfecting of wireless, both telegraphic and_ telephonic, promises soon to end the romance of the pigeon post. ———— nen This House Was Blasted Out of Rock MINER of Cold Creek Canyon, Cal., looking for something novel in the line of houses, blasted a house for himself out of a huge boulder in the mountains. He seems to have improved upon the Scripture injunction to build one’s house upon a rock, for his whole house is a rock. This unique house has two windows, a door, and a sheet- itself out. iron roof. It bears out the Biblical story; for last summer, says its occu- pant, when a fire swept through the canyon, all he had to do was to go into his boulder house and remain there in perfect safety until the fire, sweeping around his house, burned the usherettes. r Mr. Wong at an Exciting Baseball Match EE WONG — who, so far as we know, is the only Chinese baseball reporter in this country, takes his baseball through a telescope. Mr. Wong used to cover baseball for a paper in Hongkong, where the Yankee game long ago became a formidable rival of native sports. Now he is writing diamond gossip for a San Francisco newspaper. He swings his somewhat unwieldy glass with unerring precisidn and no fast infield play escapes his eye. He is said to be a wonder in dissecting close plays at the bases. the front. efficient They Are Learning the Fine Points of Usheretting “PRst aisle to the right,’ says the pleasant-mannered usherette. Next moment you are following in the wake of another soft-spoken young. woman, who guides you to your appointed place, says “Third and fourth in,” slips the programs into your hand, and leaves you feeling that if the chorus measures up to the usherettes the tired business man is due for a restful evening. So important is this first impression considered by a Les Angeles manager that he has established a school for usherettes. It is on the roof of his theater. The class meets daily to hear and discuss lectures on efficiency, dress, tidiness, and the fine art of courtesy. New costumes are provided from time to time; and this is said not only to please patrons, but to be helpful in keeping up the morale of It Beats a Hand-Car for Adventure N Alaska the motor-sled threatens to replace the dog in the transportation sys- tems of the far north, at least over important mail routes. But, if the dogs go, they will retire with honors. They had their izy-out on the battlefields of the great war, and made good. Instead of pulling sleds over snow-fields, they hauled small cars along narrow-gage rail- roads to carry food and ammunition to Their ability to do heavy work on little food made them in some places more than the fuel-eating motor. They were also easily trained to silence, and on their battlefield job silence was at times more than golden. Rear-Admiral Peary says motor-sleds will never compete successfully with dogs for polar work. Faerie nn te

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If anyone gets locked in a vault, an alarm bell over the fire marshal’s desk will soon ring, while an indica- tor on a board tells which vault holds the prisoner The person locked in need only break: a bit of glass in order to give the alarm Locked In? Break the Glass E all have heard gruesome tales about persons ac- cidentally locked in vaults—how they slowly suf- focated while they used up their last ounce of energy in madly shouting and beat- ing on the thick doors through which no sound could pass. Not long ago, after such an episode, one of the em- ployees of a corporation in Philadelphia suggested the adoption of a simple elec- tric device which has re- sulted in doing away with the possibility of a recur- rence of such anexperience. Now, if anyone gets locked in a vault, all he has to do is to seize a small hammer, hanging by a chain beside a little round frame which holds, under glass, a paper bear- ing this concise inscrip- tion: ‘If locked in, break this glass.” The moment the glass is shattered a loud gong in the fire marshal’s office sets up an alarm; and when he hears the gong the man on duty looks at an indicator that points to the number of the vault. He imme- diately sees that the doors are opened. ?, SEI SEI MES — 7 ae ONT Sd hed sh deh dh abd dn had wl i\ > ae lie: lls tl” ail” all OS a RAE NS I Oe Se On Fee = > . & & ° ms ae — RS ed ed ed SN ET AS \ i ;! xg i. “9 = a) vi After the hopper, to which the chute is attached, has been hoisted to the required height, the buckets, filled with concrete, are sent up 24 Popular Science Monthly Give Me My Point of Flour HE scale shown below is different from any scale in- vented heretofore. The indicator is not of the gravity-controlled pendulum type. And what differ- ence does that make? When the indicator of a dial scale is controlled by gravity it will always remain in an upright position when no weight is applied. Therefore the zero point of the dial is always located directly above it. That the two may coincide, the scale must be kept in an absolutely horizontal position. In this new scale the indicator is controlled by a vi- brating arrangement inside the scale itself, which is independent of gravity. Thus, if the scale is tipped, the For indicator tips too, without changing the weight. actual weighing the balance system is used. The indicator of this scale is not controlled by gravity and so correct weight may be obtained even if the scale is tipped Feeding the Concrete Chute N the construction of many modern buildings for manu- facturing or other purposes, enormous quantities of concrete are used. The handling of so much material of a semi-fluid consistency, in itself a difficult task, is made even more difficult by the fact that the work must be done quickly to prevent the premature “setting’’ of the concrete. To facilitate the rapid handling and the distribution of the material in Jarge building operations, steel towers of lattice work construction are emp'oyed by up-to- date contractors. A hopper, to the lower end of -which the delivery chute is attached, can be raised to the desired height by means of a lifting cable. The hopper is supported by a frame which slides in a groove between the ver- tical supports of the tower. The concrete is hoisted and dumped into the hop- per by means of a dump- ing-bucket which can be raised or lowered within the framework of the hoist- ing-tower like an elevator. One man can control the hoisting and pouring of the concrete. When the dump- ing-bucket reaches the hop- per, rollers.engage in the projecting ends of a curved switch extending beyond the top frame of the hopper. As the rollers follow the curve of the switch, the bucket is tilted and its contents emptied.

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i sent er, 1919 Turn the Crank and Out Comes Character O you believe that we in- herit our very natures, dis- positions, characters from our ancestors? That they made us what we are today? Very likely you don’t. But Mr. J. Gray, an English psychologist, believes it, and he has invented a machine to prove his theory. According to Mr. Gray, ‘‘perseveration” is inherited; and “perseveration” decides character. But what is ‘‘perseveration”’? It is the name that psychologists give to the property of the brain that causes a sensation—a noise, for instance—to linger in the * consciousness after it has really . stopped. Mr. Gray’s machine measures perseveration, not by sound persistence, but by color persistence. You look through glasses into the machine while the examiner turns a crank that revolves a mirror inside. The mirror reflects two lights, usually one red and one blue, mounted in the top and bottom of the machine. The speed of rotation is increased until the two colors fuse into one. You indi- cate when this seems to take place. The difference between the real fusion moment and the apparent one in- dicates your ‘“‘perseveration.”’ If these two moments coincide you are said to have ‘“‘average persevera- tion,’”’ and, according to Mr. Gray’s scale, you are consequently a prac- tical, common-sense person. If the apparent fusion occurs before the real fusion you have “low perseveration.” You are then a brilliant, suggestive, tactful, daring soul—provided your perseveration is not too low. Lower classes include cynics, punsters, and, lastly, maniacs. High perseveration characterizes scientists and writers and all other abstract thinkers. Extremely high perseveration denotes melancholia. The entire fire-alarm system of San Francisco is controlled from this room No More Terrible Fires for San Francisco F course you remember the great San Francisco.fire? Well, it is probably the last great San Francisco fire that you will remember, for the city has safeguarded itself by installing a central fire-alarm station which con- trols all the call-boxes and fire-houses throughout the city. “Moreover, it is fire-proof, earthquake-proof, mob- proof, and burglar-proof. Above is shown one half of the main semicircular switchboard. It is one hundred and two feet long. The operator sits at the center of the circle, and keeps an eye on all the boards. A revolving mirror reflects two differ- ent-colored lights in the box. You indi- cate when fusion takes place, thus showing your “perseveration” She is having her “perseveration” measured, in order to discover her in- herited disposition Just under the clock and extending on outside the picture, are the switch- boards that receive the alarms sent in. These alarms are so arranged that they will ring four times. The oper- ator then goes to the far end of the room, where six panels are located, and sends out the orders to the fire- houses. Between these two sets of switchboards are five panels, called the hospital set. These are not, as might be expected, connected with hospitals in the city, but are themselves “‘hospi- tals,” serving in case lines are broken. When a chief reaches a fire, he calls the central office by telegraph from the alarm-box and asks for anything he needs—additional engines, chemi- cal wagons, high-pressure service. An _ Operator sends out the orders. Furthermore, an alarm bell is sta- tioned at all places where there is heavy traffic for warning people and vehicles to clear the road for ap- proaching engines. The Danger of Empty Gasoline-Tanks MPTY gasoline-tanks are always more dangerous than full ones. In most cases some residue remains in the tank orcan. The remaining gaso- line vaporizes and is explosive. As the tank is being filled this mixture is forced out and will explode if ignited by a spark held near the opening. To guard against accidents, all openings should be blown out with compressed air. If this method can- not .be used the cover should be re- moved and the vapors fanned out. Unless a current of air is circulating, gasoline should never be‘ used for cleaning engines or other machinery; and if air is passing, lights should be kept at a safe distance on the in- take side of the engine.

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in America. “Tom Thumb” is what the Baltimore and Ohio christened the first locomotive that was ever built Don’t sniff too much at this engine. It was a marvel in its day, which was in the thirties i { a = se. KAKO oN Ei Garr eee aan! Popular Science M onthly , the early railways. It’s strange how the old horse-drawn coach dominated Look at this picture of the first American railway train, which made its trip over the Mohawk and Hudson (the line between Albany and Schenectady, from which the New York Central system grew) on July 31, 1832. The poor guards had to sit on Luauaal, | The pioneer inventors of typewriters never thought of writing business letters by machine. They merely want- ed to help the blind! This is the invention of Sholes, Glidden and Soule Cast your eye to the right and upward and you will behold a picture of the model of a locomotive that Matthias W. Baldwin, of Philadelphia, filed with the patent office *way back in 1842. He ex- plained how he proposed to convert the wheels into driv- ing wheels by means of coupling rods. His idea has become the standard practice Here is the first telegraph wire that ever carried a message. ‘What hath God wrought!” were the words that expressed America’s wonder in 1835 See this little sketch? It was Edison’s first suggestion of the phonograph Big Oaks from If you are an inventor don’t be show how some of the men who When next you pick up the tele- phone to say that you are not coming home for dinner, remember these first crude instruments of F Man Farmers came for miles around to see Cyrus H. McCormick turn his reaper loose in 1831. This is a reproduction of a contemporary engraving of that historic event. One know-it-all slapped his knee and said: “That invention is worth a hundred thousand dollars!’’ 26 Too bad he couldn’t have lived to see how the industry grew i . r: y ro eco F ie i

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blll a er ree rey Seer box-seats, like drivers. Incidentally, the engineers of that day were as sensitive as prima donnas. The first American-built locomotive, the “Best Friend” of -Charleston, built in 1830, blew up after a few months because its attendant lashed down the safety-valve. He was annoyed by the sound of escaping steam Little Acorns Grow too modest. These illustrations conceived the big inventions began It is the outsider that revolutionizes industries. Alexander Graham Bell’s over which the first message was sent on March Eli Whitney was a modest 10, 1876. It was telephoned from school-teacher when he the attic to the second floor below invented the cotton-gin This is where the enormous packing industry was born. Here it was that Gustavus Swift, the founder of the business now known as Swift & Company, slaughtered the eighteen-dollar heifer that started him in business When the inventors got over the idea that typewriters were to be made only for the blind, chey began to meet the business man’s needs, .and the first Remington was produced. Notice the lid, that could be swung down over the keyboard and locked. As for the typists of the early days—well, we like them if this is a specimen You still see some hand presses similar to this of Gutenberg’s of 1450 on the right. Guten- berg’s name is identi- fied with the invention of movable type rath- er than with presses Selden was a patent lawyer in Rochester when in 1877 he filed an application for a patent on what is the modern automobile. Over $2,000,000 royal- ties were paid by about eighty auto- mobile manufacturers ey ¥aaae* And this is Henry Ford in the first universal car. Ford had thrown up a job as a steam engineer in Detroit to produce this. He fought the Selden patent and beat it

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Getting Down to Earth Again Is Not So Easy Drawings by courtesy Division of Military Aeronautics. U. 8. A. age -1F GROUND LEVEL Popular Science Monthly . — ty) Pra BEEN HERE,MACHINE Trying to land at too great a speed. In the first position the machine is about to take the ground while moving too rapidly; the second position a shows it making a bad landing. The pilot is “> WOULD HAVE LANDED CORRECTLY > QND POS) IST POSITION 28° POSITION lucky enough to get away, as the fourth position indicates “Pancaking” means stalling the airplane just above the standing crops. The illustration shows how not to do it. surface of the ground and dropping the remaining two or In the first position the machine is seen to have flattened out three feet with as little forward speed as possible. Such too soon, with the result that in the second position the ma- landings are made when the ground is rough, or over water or chine has crashed. This is called landing ‘‘above the ground” Oxyacetylene Mends a Mammoth Engine Cylinder -¥ ‘HAT magic wand of modern industry, the oxy- acetylene blowpipe, added another triumph to its remarkable record of achievement, recently, when it made a wrecked engine cylinder of mammoth proportions whole again. The cylinder was on a ~ big rolling-mill engine, and a connecting-rod had bro- ken. Toappreciate the se- riousness of the accident we must realize that three hundred and sixty men were employed in con- nection with the hundreds of tons of steel produced daily by this single rolling- mill. This meant that the small army of workmen would have been laid off for three or four months had not welding been tried. . The broken cylinder was a man-sized iron casting. To be exact, it had an in- side diameter of five feet ten inches, an inside length nearly as great, and walls from two ard one quarter to three and three eighths ee the cracks in a great cylinder—part of a steel rolling-mill 28 By means of an oxyacetylene blowpipe, these men welded inches in thickness. The piston had crashed into the head of the engine, stripping the bolts and cracking the cylinder much as a knife cracks an egg-shell. There were seven cracks in all, varying in length from one to eight feet. The seven cracks were opened up by V-grooving with a pneumatic chipping hammer in order to insure perfect fusion of the new metal throughout the full thickness of the cylinder wall; then each cracked place was heated over a charcoal fire and the weld- ing proceeded with. The charcoal preheating was done tor economy’s sake, charcoal being cheap- er than acetylene, and for the further reason that in a casting of this size internal strains in the metal are avoided.by heating metal adjacent to the weld and cooling it slowly. Asbes- tos paper was thrown over the charcoal fire. The mending operationrequired just seventy-two hours. —_ oe om OM Oe oe eet CH FO

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ly Re il : - - -S ue Ce a he eet SU OU OD | eli i el ll el on i ee kk September, 1919 Is Your Child Growing Taller, Wider, and Thicker ? The mensurgraph makes exact records for purposes of comparison By P. Schwarzbach “ E’S grown an inch!” gloated your proud father when Hi backed you up to the kitchen door and made a periodic pencil mark on it. Yes, you had gained in height; put what about width and thick- ness? Had they increased pro- portionately ? The pencil mark would not tell, and your father may have gloated too soon, for only proportionate growth is a sign of good health. Exact width and_ thickness throughout the body had always been very hard to measure until Dr. Theron Kilmer, of New York, developed the ‘“mensurgraph.” The principle of this is simply to superimpose the negative of a screen on the negative of the pic- ture of a child. Screen and pic- ture are printed to- gether, which makes them both clear. Future pictures of the child will -be taken with the same camera at the same distance and with the same screening. Thus they will be similar and_ easily compared. When Dr. Kilmer takes the original Dr. Kilmer is using the same camera, the same lens, placed at the same distance from the soldier being photographed, that he used when he took the soldier’s picture six months before If the negative of a screen is superimposed on the negative of the picture the finished print will show both The white stool on which the person being photographed has black footprints photograph of a person, he stands him on a white stool that has black footprints painted on it. The footprints face both front and sideways. If the front view is taken first, the person stands on the footprints facing front. The stool is located at a fixed distance from the camera. A black T is painted on the front of the stool which corresponds to a similar T on the ground-glass of the samera. Dr. Kilmer adjusts his camera until the two T’s coincide—just as a surveyor adjusts his transit. Then he takes the picture in the powerful light of a mercury-vapor lamp. After he develops the negative, Dr. Kilmer places over it, in printing, another negative, which is opaque except for a fine-lined screening and a guiding black T. ~The finished print then shows up child and screen. The screen is stands X-ray pictures of a diseased joint taken at various times are easily compared marked off in one-inch squares for convenient measuring. It looks just like graph paper used for plotting curves from reference axes; in fact, it is used as graph paper, only in this case the curve—of the body—is already plotted. By means of these many reference lines it is very easy to compare pictures as they are taken from time to time. Dr. Kilmer uses a lens of 914-inch focal length. He places the camera ten feet four inches in front of the stool and forty-nine and one half inches above the ground. Then a child who is four feet five inches tall will be re- duced to four and five twelfths incnes on the print. This reduction of feet to the same number of inches will always hold true. The growth and development of the body are _ best illustrated by the measurements of height, the circum- ference of the head, shoulders, chest, and abdomen. In keeping a general record of a person’s development, Dr. Kilmer;reduces all these measurements to inches and then adds them together. He calls the result the number of “development units.” But the mensurgraph is not only used for recording natural growth of the body: it is used for recording the progress of deformities. The illustration that appears above shows an X-ray picture of a diseased joint. Thus growths, skin lesions, and stiff joints may all be closely watched.

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Popular Science Mo This Motor-Truck Loads, Hauls, and Spreads the Fertilizer NE of the newest pieces of apparatus evolved for the labor- saving farmer is a mo- tor-truck that does three separate tasks, and does each of them well. The first is to load manure into the truck body by means of a baom type of hoist mounted directly aft of the driver’s seat and in front of the front end of the body, and driven by the power of the engine that propels the truck. The second is to haul the manure to the field on which it is shaft that revolves the pronged cylinder, and simultaneously with it, This false bottom is like an endless platform, and pushes the manure jn the truck body to the rear end, from which jt is spread evenly by the cylinder like apparatus shown in the picture, The cylinder is pro- vided with spiked strips running longitudinally, and is revolved by a series of gears and shafts which receive their power from the regular LIFTING PRONGS p SPREADER ; CYLINDER a ee a Nel truck engine at a power S tobespread. Thethird a : take-off on the gear-set o is to spread it evenly The truck loads the manure with a boom hoist operated by the housing. engine, and its spreading apparatus distributes it over the field : over the ground. When the driver The manner in which the first and device with which the fertilizer is throws in the cylinder clutch, the fer- It third of these tasks are accomplished is_ pulled out of the pile on the ground, tilizer is automatically fed to the shown clearly in the accompanying il- swung in over the truck body by the cylinder, where the prongs pick it up Vy lustration, the second or haulage task boom of the crane and finally de- and force it out in a thin layer being the truck’s regular work. It posited into the body. The body is of even thickness determined by the Un may be seen that the hoist is fitted also fitted with a moving slatlike false relative position of the prongs above pli with a special form of tongs pick-up bottom which is driven off the same the floor of the truck. sev the . ; ° ° for He Made His Own Truck Crane — Heaviest Load on Rubber Tires . i MOTOR-TRUCK owner in Brooklyn, N. Y., who HAT is said to be the heaviest load ever carried on ele owns a small repair shop, accomplishes the same VY rubber tires is the forty-ton marine engine cylinder en restilts as those of a costly overhead traveling crane by means shown below. This tremendous load was recently hauled sit of the home-made hoisting device illustrated below. It is for twenty-three miles over the streets of Los Angeles to sh simply a large-sized horse mounted on rollers. Itis moved San Pedro without damage to the streets or to the rubber ju over the truck chassis, the feet of the horse straddling the tires on which the carrying trailer was mounted. The tl chassis frame on each side. A block and tackle or differ- trailer was specially constructed for the work, and will m ential block is suspended from the center of the top cross- safely carry as much as fifty tons. ci arm and easily lifts out any truck part. When the part The load was so heavy that two tires, each has thus been removed, it may be transferred to any other ten inches wide and forty inches in di- 3] location in the garage by moving the horse to the desired ameter, were placed side by side on V point, when the part may be deposited. each built- up metal wheel. : mee * “ . te 4 ; . Fe # \¥3 # ie ne By ees j : Efficiency is the key-note of the modern repair shop. This Hauling forty tons for twenty-three miles on rubber tires is the proprietor made his own crane and saved money thereby unusual stunt of a Los Angeles truck. The tires were uninjured 30

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IS pro- 1 strips linally, by a l shafts their regular power ear-set river 1e fer- Oo the it up layer oy the above es ied on linder 1auled les to ubber The d will 3, each in di- de on — ‘ = . 1919 V Special truck bodies for certain types of work are receiving the attention . of large manufacturing concerns. Here is a body that is easily removable Bees” It Can Be Removed for Platform Work 7 HILE the large increase in the parts of trees, roots, etc. ‘ -use of motor-trucks in the To satisfy the demandsfor [fF United States and the great multi- theexpressservice,asimple ‘4 plicity of their tasks has resulted in several firms bringing out truck bodies that are readily convertible from one form to another, as shown in recent issues of POPULAR SCIENCE MONTHLY, it is unusual to see an express type of elevating body that may be removed entirely from the chassis without con- siderable work. However, the body shown in the accompanying pictures is just such a body, and may be rolled off the truck chassis frame in four minutes’ time to enable logs to be carried. - The body shown was made on special order for a California farmer who wanted to use his truck for bring- ing express shipments from the station; to carry road material used for the maintenance of drives; and to carry unwieldy objects, such as crooked type of flareboard body was sufficient. But for carry- ing bulk material some means had to be provided for elevating it, so that the material would run to the rear end. This was accomplished by fitting a conventional type of hydraulic hoist just in back of the driver’s cab. But, in order to spread such material evenly on the ground, a special form of double tail- gate was provided. This is a gate within a gate, the outer being hinged at the two bottom corners and the in- ner at its two upper ends. The open- ing of the inner gate is controlled from the driver’s seat. : So far, the body is not so much out of the usual; but when provision is arcH a ‘S The tail-board operates on two sets of hinges, one to permit sand-load emptying, the other for sliding out heavy material. A hydraulic hoist raises the front end made to remove it entirely from the chassis it becomes distinctly different. In the first place, the connection between the vertical lifting cables of the hoist and the front end of the body may be broken readily because the ends of the cables are formed into loops which are slipped over hooks in the body. The entire body may be slid off the longitudinal wood sills on top of the truck frame proper and the body sills used for carrying lumber. Brazing Cracked Castings at Low Temperature HE discovery of a new low-temperature brazing com- pound, called nicro-spelter, makes it possible for even thoroughly, and the edges beveled off to form a V, to give the added material sufficient body to hold it in the least skilled mechanic to braze together cracked castings place. Second, the material along the line of the crack made of iron, bronze, or brass. The new compound, worked out by K. R. Peters, of Chester, Pa., melts at This comparatively low temperature may be secured by the use of an ordinary 300° F., brazing perfectly. blow-torch. The compound has been found especially _suit- able for automo- bile work. The four views shown here illustrate the four steps neces- sary in repairing a cracked engine water-jacket. First, the crack must be cleaned A new compound for brazing iron, bronze, or brass castings melts at 300° F. It is permanent and wear-resisting, and can be worked by an unskilled mechanic 31 is heated for a moment with an ordinary hand blow-torch and the spelter runinto the crack. The third step is to roll the compound flat or flush with the surface of the casting while the former is still hot. This is done by means of a small roller similar to that used by stationers in pasting paper together. After the casting has been allowed to cool off for about five minutes, it is necessary only to dress off thesurface with a file to com- plete the repair. ve issn EEO ES

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What Becomes of a Dollar’s Worth of Gasoline AS your automobile purrs sweetly along the road, do you ever try to figure the gasoline inevitably lost by your engine before it gets a chance to transmit power to the driving wheels? Not more than twenty per cent of the energy in the gasoline is delivered by the average is cavencnan automobile engine, although twenty- churns out a dollar’s five per cent is attainable. Here's worth of gasoline. @ series of pictures showing where Find out just where the leaks are and how to stop them it goes and how it could be economized Twenty-five cents of your dollar is ejected in smoke from the exhaust. Ad- just the car- buretor to its highest _ effi- ciency; hold the oil ata constant level; and beware of black smoke Forty cents of your dollar emerges from the radiator. Keep the cooling system in perfect condition and _ the engine as cool as_ possible. In addition, make sure that the fan is functioning properly Twenty-five cents of the dollar mixes with the air that circulates over the en- gine. Moral: Never race the engine and never allow it to idle. Battery recharg- ing is cheaper than purchasing gasoline And now you must buy more gasoline. ; Attach a safety cap to your filler Only ten cents of your dollar drives the car over the road. Manipulate the hand tank, and have some means of mak- throttle when driving over rough roads. Coast whenever possible on grades and hills ing sure that you get a full gallon 32 TRIS CT ATE RPI a ANE A eS,

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* September, 1919 Where the Pearl Button Gets Its Start

_ pearl buttons that you buy for your clothes are obtained from the shells of the fresh-water mussel. A lively mussel-fishing industry has sprung up along the banks of the Mississippi river and its tributaries. The mussel- fishermen go out, praying that they will find pearls worth, it may be, as much as three thousand dollars apiece. Once a year or so they find a pearl or a slug. But even the shells, which are thrown to one side and sold to pearl button makers, are worth twenty dol- lars aton. What becomes of the dead mussels? Oh, they are thrown to the pigs or the chickens, or used as fish bait

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The story of your pearl buttons be- gins with the infec- tion of a fish with the larvae (glochid- ia, the scientists call them) of the mussel. The larvae, it seems, are ex- pelled by the parent mussel, and attach themselves to the gills, fins, or other parts of fish un- fortunate enoughto be swimming around at the time. The men in the pic- ture above are sci- entists who are sort- ing the fish that are to be infected with the larvae or glochidia of the fresh-water mussel

A flat-bottomed, square-end boat, commonly called a John-boat, is em- ployed. Two long iron bars are car- ried, to which are attached by short wim lengths of cord some one hundred ® hooks. . The fisherman throws one of the iron bars overboard. As soon as 3 the hook enters the open shells of a ¥ feeding mussel, the shell closes tightly The black crappie carries the glo- chidia of several species of mussels and thus serves as an unwilling host SSS ie SNAP NNN HN < a nnn NINN These buttons were cut from shells of mussels raised from the glochidia stage in the ponds of the Fairport Biologi- cal Station, of the Bureau of Fisheries. All of which shows what science is doing in the matter of your personal adornment 33

The little specks are the glochidia, or larvae, of pearl mussels; the straight finger-like projections are the gills of a fish. Behold the glochidia at home

Since the larvae of mussels thrive on the gills of fish, we find that the Bu- reau of Fisheries has developed a inethod of collect- ing the fish in nets and transporting them to infection tanks, into which the larvae are in- troduced. It takes only a few minutes for the lively little larvae, or glochid- ia, to. establish themselves in these free boarding- houses. The fish are liberated in ponds, all unconscious of the part they are playing in button- ing up mankind

The glochidia of the “nigger- head ”’ mussel, one of the most val- uable commercial species, are the special uninvited guests of this river herring. The scientists also supply large-mouthed black bass and other varieties forthe glochidia

Here the glochidia—the beginnings of so many pearl mussels—are drifting around looking for a home. Eventually they will find it in the gills of fish + moe"

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BSE RE PEASE SEBS S SE The posts on the Cana- dian border are guard. ed simply by the flags of the countries A stone post marks the border between the United States and Mex- ico; this man has a foot in each country Popular Science Monthly Throw Out the Clutch and Coast O wonder she smiles! J.B. Allen, of Pueblo, Col., has just made her a hand- car that has a coaster- brake, and also a curved bar attached to the handle for exercising her left foot, which is par- alyzed. As she moves the handle her left foot moves with it, . while her right \ foot rests on the front axle to do the steering. The en ae HAND LEVER oF 4 (RAISED) ie Her hand-car is sup- plied with a coaster- brake; it also has an attachment specially designed to exercise her paralyzed left foot inca s——, ~ SEAT coaster-brake is worked by a lever, which she . Where the U. S. Ends HE Mexican and Canadian border lines of the United States are not lines at all, but rather a series of posts. The posts along the Mexican border are carefully caged in— perhaps to prevent anyone from moving the border. Our illustration shows an American performing the exciting feat of standing in two countries at one time. On the Canadian border the posts are unguarded except for a flag-pole on either side, each of which flies the flag of its country. One of the interesting features of national borders is that a fleeing criminal is out of the hands of the police once he has taken a step across. Though the police may be able actually to touch him, they cannot legally do so. When You Can’t Move That Bolt UTOMOBILE parts that have become over-tightened, such as nuts, bolts, or spark-plugs, are sometimes very difficult to remove, especially when they have become rusted into position, and when the use of excessive force may damage and possibly cause some breakage to the parts. If the tightened part will now holds in her right hand. When she pulls the lever up, a clutch that engages the spokes of the wheel is withdrawn, and the car coasts. The brake is applied by the same lever. When she pulls it a little higher, a bar comes down on the rim of the wheel, causing the car to slow down or stop entirely, de- pending on the amount of pressure used. After watching this little girl ride around in her car, a man who was also paralyzed ordered a somewhat similar one for his own use. Chalking the Chalk-Line HEN is a shoe not a shoe? When it is a chalk-line holder like that invented by John S. Wakimoto, a Japanese resident of Grand Island, Neb. Look at it. It has the form of a woman’s low shoe, with a pointed toe and high heel; but there the resem- blance ceases. The chalk-line, when not in use, is wound around the drum of a reel which is placed in a recess of the wooden shoe between the heel and the instep. The line passes through a channel running lengthwise through the The recess opening is closed with a felt stopper, which on be- ing pressed down brings the chalk in contact with the line not loosen under ordinary pressure, pour a little kero- sene at the seat of the trouble, giving it ample time to pene- trate. If this does not prove successful, try the effect of heat. In case the refractory member is in contact with the cylinder, run the engine for a short while. In other cases a blow- torch may be_ employed. When no blow-torch is avail- able, .a bit of waste soaked in gasoline and wrapped loosely around the tightened part, when lighted, will heat the metal sufficiently to ease the joint and permit the part form of a woman’s shoe. to be removed. This chalk-line holder and reel does not have to be in the It would work just as well in any other shape, if essential parts were unaltered 34 shoe to a forward recess which contains chalk, and thence through an opening in the tip of the toe. When the line is to be used for marking, the free end is fastened to a peg or a nail, and the required length of line is reeled off the drum. As the line is pulled out, it comes in contact with the chalk and is coated. After the work is com- pleted, the line is again wound around the drum of the reel. Before the line reaches the reel, the surplus of chalk is brushed off by a feltlike pad over which the line must pass.

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sleeper ast September, 1919. Locomotives Are Consuming Too Much Coal But a feed-water heater has been invented that will save at least ten per cent of every shovelful HERE is a tremendous waste of 45 ‘eoal in firing locomotives. Cold water is sucked from the tank in the tender by means of an injec- tor and fed into the boiler. The heat generated by the burning coal turns the cold water into hot water and then into steam. The steam is fed to the cylinders, at high pressure, and its power is transform- ed into motion by reason of its impulse to expand and push on the pistons con- nected with the driving mechanism of the locomotive. Heat Goes Up the Smokestack The exhausted steam, having done its work in the cy- linders, is blown away through the smokestack, carry- ing with it sixty-five per cent of the heat consumed in changing the coal to steam. To avoid at least part of this waste, a feed-water heater is employed in many modern locomotives. The heater returns to the boiler some of the waste heat of the exhaust steam, and thereby saves at least ten per cent of the coal bill. In other words, nine pounds of coal, together with the feed water heater, does the same amount of work as ten pounds of coal in the average locomo- tive without the heater will do. A saving of 10 per cent of a substance as valuable as coal has become is no mean achievement. How the Feed-Water Heater Works The feed-water heater, which is shown on this page, takes one sixth of the exhaust steam ordinarily sent up through the smokestack, and utilizes it for heating the water before it is fed into the boiler. of the steam is sufficient to provide the necessary draft for the boiler fires. The one sixth used to preheat the water saves about thirteen per cent of the heat in the exhaust steam. By putting this back into the boiler SAFETY CHECK VALVE "EXHAUST STEAM to” FROM CYLINDER INTO FEED-WATER HEATER Five sixths By Joseph Brinker ten per cent of the coal burned is saved. The feed-water heater is a cylindrical tank, which is generally placed just ahead of the front end of the boiler, directly on top of the cow-catcher framework. INJECTOR (HEATED WATER BACK INTO BOILER) —— EXHAUST 1 PE AIR-BRAKE PUMPS COLD WATER TO FEED-WATER HEATER By making use of some of the exhaust steam of the locomo- tive for preheating the water that is fed to the boiler, the cost of coal for an engine can actually be reduced ten per cent The feed-water pump forces the cold water from the tank in the tender to the intake of the heating tank, where it passes through a series of tubes around which exhaust steam, taken from the valve chests of the engine cylinders on each side of the boiler, is allowed to circulate. The Water Is Preheated to 250° Fahrenheit The steam heats the water as it passes through the pipes, so that when the water reaches the boiler it has become so hot that little addi- tional heating is required to change EXHAUST STEAM COLD io FROM_ BOTH WATER | IN et ‘THIN BRASS SPIRAL AGITATORS When the water reaches the boiler it is so hot that it needs only a little additional heating to change it to steam of the adequate pressure 35 COLD WATER FROM TENDER ~ it to steam of adequate pressure. When the exhaust steam gives up its heat to the cold water in the pipes, part of it is condensed to water, which is drained off at the bottom of the tank. ; The heater is closed, and will there- fore deliver water to the boiler at a temperature propor- tional to the back pressure in the en- gine cylinders. In an open vessel water boils at a tempera- ture of 212° Fahren- heit. But when a locomotive is run- ning at high speed the back pressure in the cylinders is sometimes as high as fifteen pounds. At such times the exhaust steam may have a temperature of 260°. When this is the case, it will heat the water to a temperature of 230° or 250° before it is fed to the boiler. Since the water passes through the tubes while the exhaust steam circulates around them, it remains free from the vaporized lubricating oil that is invariably contained in ex- haust steam. If the oil vapors were pumped back into the boiler they would form a heat-consuming scale on the boiler-tubes. A Removable Head Provided at Each End For the sake of greater convenience in cleaning the heater, a removable head is provided at each end. The tubes are nested in four distinct groups, separated from one another by plates which divide the interior of the heater into four longitudinal sections. On its way to the boiler the water passes through each of the ‘four compartments. This means that it has to pass through sixteen feet of tubing, while the length of each of the four units is only four feet. To bring each part of the water into contact with the heating surface of the pipes, spirals of brass are pro- vided in each pipe. These rotate at high speed as the water passes through the pipes. See ee mt ee i 8 a Re

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A Traveling Kitchen on a Trolley Car HyiArry folk, they who live in Halifax, England! No worry about buying supplies or cooking them. All they have to do at meal-time is to carry the dishes out to the trolley track and wait for the traveling kitchen to come along. Alderman Charles F. Spencer, Director of National Kitchens, is father of the idea. He took an old trolley car, fitted it up with elec- tric ovens, steamers, hot plates, and boiling-pans} installed a 100- gallon water-tank on the roof, and sent the car on its journey. The car cooks as it travels, taking its energy from the over- head trolley. ANTAL AMNNHH Taming the Bolshevik Turkey OST of us consider the turkey a domestic fowl. Heis not. He is the Bolshevist among farm birds. He refuses to submit to barn-yard government except when feed cannot be obtained by foraging. To keep his turkeys out of the neighbors’ corn-fields, one farmer fitted up an attach- ment that at first glance looks like a turko- plane. the turkey’s neck and tied by a heavy cord that passes under the wings. It is merely a board fitted around I Win, lm Uy Mm, Mm , The World’s Oldest Wooden Vessel Still Afloat N 1805 the Polly first sailed the ocean blue, and she is still doing it. Her birthplace was Amesbury, Mass., and since the first moment she took the water she has been working as a coastwise freighter. Several years ago, when the Polly began to grow famous for her long, active life, the newspapers—as so often happens—hunted for possible scandals in her youth that they might feature in their pages. They came out with the story that in the War of 1812 she was a privateer. But this was prompt- ly and indignantly denied by her friends. So the newspapers gave up and the Poily has gone on her peaceful, respectable way. The schooner has a capacity for only forty-five tons freight; yet in her day she has carried enough lumber, bricks, and lime to build a large city of wooden houses. Think of the long line of captains who have sailed the Polly and the crews that have manned her through more than. a hundred years. What human interest stories she could tell if she could only speak. 36 Cl ff MM LOLLMCALLMLLLLULAMUULLLELLLLMLLMULULALLLLLMLLLLLULL MULLIN LOLA MOLL Wh “lity - Popiilar Science M onthly Take Heed, All Ye that Enter Here 7 greatest safety device known is a careful man,”’ says the sign near the approach to a certain time- card rack; and to impress the need of care on the careless, a railroad that has made a specialty of “Safety First”? campaigns has in- stalled the sign-board turnstile. shown above. Workmen must pass through the stile. The time-card board where they get their cards on entering in the morning is so placed that as a workman halts to get his card he is confronted by the turnstile, where a board at the level of his eyes carries in three languages the warning to BE CAREFUL. Carry a Bed in Your Pocket ITH air cushions such as this the Jap- anese make easy the seats of the lowly as well as of the.mighty. Lacking rub- ber for such purposes, they make punching- bags, bed mattresses, water vessels, and air cushions of a strong bamboo fiber some- times called “leather-paper.” It is very tough as well as light, and has so little bulk that one might easily carry his bed in a good-sized coat pocket. The material is shellacked and built up in layers, the grain of each layer crossing its neighbor. The product is water-proof. The pillow below has been in use fifteen years.

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September, 1919 : : per © Keystone View Co.

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herewith, was pro- moted from its place on the floor to a nail

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in the wall. Now it catches bills, which are not near- ly so messy. What is more, the mouse- trap has been given a name — “The Little Nipper’; and its name

is painted on it in large, al plain letters. Before the mouse-trap took up post, of course, it was thoroughly washed and all the unnecessary parts were removed.

The Real Turkey Trot CONDEMNED man’s last moments are made as easy for him as possible; but a con- demned turkey must suffer. In the first place, he is usually made to walk from the farm to the railroad station. Then he is stuffed into a freight-car with too many of his brethren. If the roads are rough and full of ruts he becomes foot-sore. “Is this fair?” cry the tender- hearted poultrymen of Texas, where the roads are bad. And so the farmers of Texas have start- ed a “‘better roads” campaign.

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He’s Taking His Lesson in the Flipflap -[ ‘HE music begins, the curtain rises, and out come the acrobats: As they tumble, twist, and turn, you wonder how they are able to do it so easily. But this easy performance comes only after long practice. Take, for instance, the flipflap. In learning to do this, he puts on a belt, which is fastened by a rope . to the wall. He bends back until he touches the floor; then the in- structor jerks the rope upward, bringing the acrobat into an up- right position. Walking Up an Iron Pole BY means of a climbing ap- paratus invented by Mr. Crowther, of Manches- ter, England, it is now possible to go up an iron pole quite easily. The apparatus con- sists of two clamps, one for the feet and one for the hands. First the climber adjusts the lower clamp and stands on it; next he clamps on the upper one, which has projecting handles and to which a waist-strap may be attached. After grasping the handles firmly he pushes the lower clamp upward with the feet. Thus, by adjusting first the foot clamp and then the hand one, he walks up the pole. Soe

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Fas es. eee The Dungeon T’S unhealthy. You of Rot—A Sinister and Odorous Place are certain of that the instant you step inside the door. A wave of air with a humidity of something over ninety-nine per cent, and as-hot as Sumatra in July, makes you long for an. electric fan. Besides, there are smells—smells woody, earthy, and slimy. A long line of glass- doored cupboards confronts you. On the glass hang beads of perspiration. As you tentatively open one door you realize where all the odors are coming from. Fungi of all shapes, sizes, and colors hang on pieces Popular Science Monthly of decaying’ wood therein. A few are-of the conven- A laboratory for studying the diseases that attack wood. Behind these glass doors are kept all kinds of sinister brown on top and sickly white underneath. Here is another, a whitish gray arm, twining itself around a hickory branch. All the kinds of wood-rot in the United States are repre- sented here. It is the laboratory of experimental wood path- ology of the Forest Prod- ucts Laboratory at Madi- son, Wis. Here are kept all the diseases that can attack wood, and wood is inoculated in order to dem- onstrate the effect of dif- ferent toxins. The toxins are mainly mineral poisons, which may safeguard vari- ous kinds of wood against rots, if the tests result sat- tional “sunshade” type, exhibits—wood-rots from every part of the United States isfactorily. HE i shis 4 : t tely, i tures’, Millions of Dollars in the. Despised Corn-Cob = n#*#lv,, in spectacle of West fiber- the grain-dealer of the middle West cart- ing corn-cobs to the river-bank and in- viting the high tide to sweep them away, and the old-fashioned corn miller of the South banking them in the mill or choking the narrow-gaged stream with them—these time-honored practices are destined to a speedy end. Corn-cobs — heretofore considered the veriest waste—are to be salvaged and made into glue. Moreover, the grain-growers of Ohio, Indiana, and other middle Western states may soon be shipping eggs across the con- tinent, or perhaps to Siberia, in con- tainers welded together by corn- cob adhesive. America is the world’s chief pro- ducer of corn, the annual yield rang- ing between two and a half and three billion bushels. For every bushel of shelled corn there is approximately one bushel of cobs; and one hun- dred tons of cobs will yield thirty tons of glue. Recent experiments by chemists show that in wasting corn-cobs we have been throwing away millions of dollars every year By S. R. Winters “Imagine all the available corn- cobs transformed into profitable uses, and there would be enough glucose to fatten all the cattle raised in the United States or a source capable of yielding all the alcohol used; a supply of baking powders sufficient to ‘raise’ all the biscuits ever baked; and there would be no such shortage of acetic acid as exists today.”’ Sounds like a fantasy or a tale from Arabian Nights? Not so—we quote Dr. Frederick B. La Forge, chemist in the Bureau of Chemistry, United States Department of Agriculture. He has successfully developed the process of making corn-cob glue. Since corn-cob glue is to compete with the cheapest variety of adhesive and is to be used principally in mak- ing fiber containers, the proximity or remoteness of fiber-manufacturing plants is fundamental to the success or failure of the corn-cob industry. For- container manufacturing enterprises are thickly clustered. Corn-cob adhesive would take the place of sodium silicate (water-glass), a glue obtained by fusing soda and sand. The mixture is used exclusively as an adhesive, and is expensive. The product commands from forty- five to fifty dollars a ton. In cheap corn-cob glue of high sticking qualities sodium silicate finds a rival. Fixing the price of coal at five dollars a ton, and estimating the cost of delivering the cobs at the manufacturing plants at three dollars, the finished product could be made for eight dollars a ton. Three per cent of the yearly produc- tion of corn-cobs would supply ad- hesives equal to the combined con- sumption of today. Hence the quan- tity of raw material appears limitless. Moreover, starch, dextrine, and flour paste — components of foodstuffs — would thus be diverted to their normal uses for human consumption. For every bushel of shelled corn there is a bushel of cobs; one hundred tons of cobs make thirty tons of glue

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oO. es O'S September, 1919 Mothering the Airplane with the Zeppelin How the British launch airplanes from their giant dirigibles always troubled by the diffi- culty of launching their ma- chines. “If I can only get off the ground,” each one of them said to himself, ‘‘I will fly.” Dozens of machines were wrecked before the trick was learned. Now, the Zeppelin dirigible had been brought to virtual perfection somewhat before the pioneers of flying had fully solved the problem of launching. Why not launch a flying-machine from a Zeppelin? The suggestion was made over and over again, It seemed easy to start the airplane from a speeding rigid dirigible, for the wings would re- ceive both the speed and the sup- port that they need, with no inter- ference from wind-gusts. The non-rigid type of dirigible would hardly have lent itself to the purpose; it could not lift enough. But the plan was well worth trying oe pioneers of flying were with a Zeppelin traveling very low over a flying-field. Probably the test was never made, because the art of handling a Zeppelin in the air was acquired only with diffi- culty after years of experi- By Carl Dienstbach ‘» Dropped from a Zeppelin in a flying-ma- chine! He can return when he pleases and hook himself to the Zeppelin mother- ship; but the trick requires skilful pilot- ing and a nice regulation of air-speed ment. The early Zeppelin navigators had_ troubles enough of their own with- out risking lives in launch- ing a flying-machine. With the modern Zep- pelin and the modern air- plane the result of such an experiment isa foregone con- clusion. An airplane could be dropped even from a captive balloon at this late day, and the balloon would hardly be endangered by the sudden release of so much weight. Have not the fight- ing flyers shown that they can control their machines when they are dropping tail first, or slipping down side- wise, or looping the loop? What would be the good The British have made the novel experiment of using the Zeppelin as an airplane mother-ship. Fer- haps the idea was suggested by the Naval mother-ship of the seaplane. What is the good of the combina- tion? The airplane can be released at any moment, to fly ahead and recon- noiter hostile terri- tory. Returning, it tells the Zeppelin’s captain whether or \_ not he may proceed of the proceeding? Would the air- plane serve as a kind of life-boat? Hardly. It could not carry enough weight. On the other hand, a small airplane would haveitsuses. Piloted by an “ace,” it might give battle to an attacking airplane or carry out a reconnaissance over hostile territory. This idea of using the giant rigid dirigible in connection with an air- plane has been practically tested by the British. No doubt the British experiences with naval mother-ships for seaplanes suggested the pos- sibility of converting the Zeppelin into a similar craft. Considered as a mother-ship, a Zeppelin becomes a formidable fighter and a most effi- cient scout. Use the Zeppelin as a mother-ship, and the advantages of airplane and rigid dirigible are perfectly combined. Not only can the airplane leave the Zeppelin in full flight at any instant, but it can return just as easily. The dirigible has but to run at top speed and the plane at its low speed. The two vessels leisurely come _ together. Blériot hooked his moving plane even to a stationary wire years ago. Lieutenant Locklear has shown how easy it is to leap from one plane to another. The more we consider the possibilities of the Zep- pelin as a mother-ship, the more we wonder why the Germans did not carry out the idea. It remained for the British to reveal its possibilities. The Germans might have made similar Does the carrying of an airplane by a Zeppelin in this fashion impose an unnecessary additional burden? Not at all. airplane wings can be so inclined that they exert their maxi- mum lift, and the airplane engine may be permitted to run 39 The experiments for the last ten years; but apparently they lacked the imagination that was necessary. Soar — is ne: LEE a Se

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a ee i RRS TE Shooting Mont Down-a Chute > UT’ em right there!’’ says the warehouse- ae . '-man,-as the truck-boy slides.up with his elixtric truck filled with packages. The boy dumps his load:-on the floor, and the ware- + #t ~ houseman looks down from his eyrie on the Wp BAX é waa / : RAM, Down this slippery stony one hundred and fifty thousand pounds of meat passes every day twelfth floor to see that all is clear. Then he begins to slide the packages through a hole in the wall down to the loading-dock below. Don’t they get smashed up? Oh, no; they slide gently to earth down a gravity spiral conveyor. The conveyor is not necessarily spiral, but it is always inclined. The platform upon which the mer- chandise moves is paved, so to speak, with ball-bearing rollers. There is just sufficient incline given to the track to cause the packages to slide down by their own weight. Such a conveyor saves miles of walking and hours of time that would otherwise be spent in trucking and in elevator service. It also economizes on floor space. The conveyor can be adapted to both inside and outside use, and can be made either portable or fixed. The one that forms the subject of our illustration has been working continuously for ten years, and has a capacity of 150,000 pounds of packed meat a day. CONTACT POINTS Want to see the time in the dark? Then carry your watch, an electric light, a bat- tery, and wires inside your motorist’s glove Night-Time—How to See It ADIUM paint is not the only thing that will illuminate a watch on a dark night. So saith Benjamin F. Lockwood, somewhat defiantly, for he has just invented a decidedly com- plicated device for so doing. In the first place, you must wear a motorist’s glove; then you attach your watch to the back of the cuff; next you adjust the bulb and shade so the watch is illuminated. A battery is tucked in the side of the glove, and wires run around till they terminate in two contact points in the thumb and first finger. When you wish to see the time, act as if you were pinching someone and the lamp will light. It Moves a Loaded Freight-Car wheel to revolve. This new pinch- bar has a member curved to fit the wheel. Under pressure this mem- ber will convert the lifting force into a pushing force O you know what a pinch-bar is? It is somewhat like a crow- bar, and it is used for moving loaded freight-cars. It is pushed between wheel and rail and a prying motion causes the In the old-style pinch-bar much force is wasted in lifting the wheel instead of pushing it. This tool consists of a shoe that fits the top of the rail and is braced against the track; the pinch-bar proper, which is pivoted at its bend to the shoe and has a strong wooden handle; and a mem- ber shaped to fit the curve of the wheel and pivoted to the end of the pinch-bar. When the handle of the pinch-bar is pushed downward, the curved member engages the rim of the wheel and This is overcome in a new pinch-bar. changes the vertical force exerted by the short end of the lever to a horizontally acting, pushing force. With the aid of the improved type of pinch-bar One man can easily move a loaded freight-car Popular Science Monthly. . | es ee ea” « ee eine

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© geghémber, 1919 Putting Bad Smells to Good Use OW do:you know that a skunk has invaded your neighbor- “I -hood?.. That the family next door is going to have ham and cabbage or steak with fried onions for supper? Or that a gas-pipe is leaking? The keenness, alertness, and reliability of the human nose as a detector of smells, good and bad, suggested the idea of using distinctive odors for conveying warning signals to workers in mines and factories. The United States Bureau of Mines ex- perimented with a number of substances of pronounced pleasant or unpleasant odor, and found several exceedingly offensive stenches, powerful at low concentration, particularly suitable for use in mines. The substance, in the form of gas or vapor, is mixed with the air that is forced through the mine for ventilating purposes. In a few moments the stench - laden air permeates the mine, and the miners are given an oppor- tunity to save their lives. Some stenches, like amyl thioether, allyl isothiocyan- “ke ate, amyl isovaler- ate, phenyl isocy- anate, and isobutyl mercaptan, can be detected in a dilution of 0.2 to 3.5 in one mniillion parts of air by volume, and are strong when diluted at a ratio of 1.7 to 11 parts by volume in one million parts of air. Thefirst whiff of stench- laden air warns them of danger A Sea Home for the Seaplane FLOATING hangar—a ship with seaplane-landing facilities— has been invented by Maximilian C. Schweinert, of Hoboken, N. J. The seaplane lands on the water and taxis toward the ship, whereupon the ship lets down a gang-plank. If it has wheels, like some of the German ‘‘Gothas,”’ the seaplane taxis up the gang- plank into her berth. Then the gang-plank is raised to an upright position, in which it serves as the door of the berth. In spite of the dense fog below, the aviator would find his home field by means of an illuminated balloon; the lights strung down the cable guide him to a landing-place Helping the Flier to Find His Way Home t " HICH way shall I fly?’’ quotes the optimis- tic airman. He himself—not his paradise —is lost. A CUSHION CLEVER A gang-plank is lowered from the side of the ship to the water and the seaplane rides up to her berth within the hull, which is fitted up as a hangar and repair shop 4l His radio compass has gone bad; a heavy fog completely hides all guiding lights on earth. True, the stars shining brightly above help him to find his approximate latitude and longitude, and he knows from his propeller the speed at which he should be flying. But is he drift- ing off his course, and if so at what rate? He cannot tell. If he tries to land he may crash into a tall building and be killed. Aerial guiding lighthouses would eliminate to a great extent this danger in flying. Captive balloons, equipped with high-powered search- lights, might be flown from aviation fields and well known landmarks. Lights of different colors attached to the cables near the top would indicate the various names of the places below: for instance, a red light above a blue. one might mean the Mineola aviation field; whereas two red lights could mean the Times Building, New York. Furthermore, it has been sug- gested that lights be strung down the cables leading to aviation fields. Then, if an aviator spiraled down around these lights, he would be sure of a good ianding--place.

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REHOS SMT, 1 Neate pr Thousands of Japanese spend their lives King Silkworm Lidddldlds LLL ulacladddddadddiddddddddddddduuldddddddiuuiiddddg, Silkworms ought to be beautiful, but look at them; they are just as ugly as any other worm. The silk indus- try originated in China; but the Japanese real- ized its importance to such an extent that in some of their villages every home is a silk- worm nursery. The worms are here feeding on the mulberry leaf Japan takes in forty million dollars yearly in her silk industry. The gov- ernment has estab- lished a free school near Kyoto for teaching the busi- ness thoroughly Oe ee a 2 Oe » We a adds idasadadddddddddddauldddaddldddddddddasdidddddddddbddddddddsalisdidddddddddddsbdddssdididdddddddddedddddaddddaddbddddddddadsdddddddddde, Skeins of the beautiful shiny stuff as it goes to the “silk throwster.” Its length is frequently a thousand yards i The silkworm is probably the only worm that gets any human help in the pursuit of its business. cocoons silkworms need plenty of space. Here the kindly Japanese are preparing aba, or supports for them to spin on In spinning of this autocrat 4 neo aad SSR AAA AALE IN NALA Popular Science Monthly in the service Eggs, cocoons, and moths of the silkworm. In winter the eggs are carefully spread out on sheets of paper and placed on trays. When the larvae hatch out, their human attend- ants chop up mulberry leaves and scatter the pieces over the tiny worms. As they ma- ture each worm re- ceivesawholeleaf aday But weaving at home is still carried on to a great ex- tent, as witness this Japanese woman, who is employing a rather primitive method in the weaving of raw silk Photographs © by Newman Traveltalks and Brown & Dawson The thread consists of silk fibers wound together, the separate fiber having been actually spun by the worm It is when the cocoon is completed that the ulterior motive of the silkworm-owners appears. The chrysalides in their cocoons are killed in boiling water, and the threads are separated. Then the filaments are unwound and spun for the weaver

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Li PAAOMNMWVWMWWVVB “Beplember, 1919 Amazons in the Making It appears to be a happy as well as healthful operation Ready to dance? Not in those shoes; they are heavily weighted in the toe and are used for exercising the legs. Such shoes ano conciny In her hands she holds a sand-bag, thirty inches “cc y 93 , known as “pedal dumb-bells long and five pounds heavy. When her arms grow tired she will slip her foot into the strap on top of the bag and raise it up and down Though it looks very much like an iron han- dle, it is really a new kind of dumb-bell. It must be held tightly while in action or it will topple over; for the weight is con- centrated in the upper half While her right hand Five pounds of sand holds the bag on high, hanging from her foot She balances by rest- disturbs this young ing her left hand woman not. at all. on her hip. In this She takes to it as position she manipu- easily as if she were lates the bag easily going upstairs 45 Now she treats the sand-bag as if it were a Roman candle— whirling it skyward through the air. The pull she must exert in order to keep it from flying off at a tangent is a good muscle - developer ¥

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The revolving arms of the scraper move slowly, making but four turns every hour, for any rapid movement would interfere with the settling of the fine particles of dust. The power consumed by the scraper is exceedingly small Scrubbing Iron Out of Furnace Gases NE of the by-products of iron- smelting is the gas that is gen- erated in the smelting furnace by the distillation of the coke that supplies the carbon for the deoxidation of the iron ore. The carbon, at the high temperature in the furnace, combines with the oxygen of the iron ore and forms a mixture of gases, one of which, carbon monoxide, is combustible. These blast-furnace gases escape through the vent of the furnace, and are laden with flue dust, consisting principally of fine particles of iron, manganese, silicic acid, aluminum oxide, lime, and carbon. Before the escaping gas can be used for the heat- ing of boilers it must be purified. First, it is allowed to pass through a “settling chamber,” in which most of the larger and heavier particles drop out and collect in pans at the bottom. The finer particles, small enough to pass through a 100-mesh screen, re- main in the gas and are removed by “scrubbing’’; that is, the gas is washed by passing it through water. The water that comes from the “scrubber” carries an average of two hundred grains of solids to the gallon, sometimes as much as three hundred and fifty grains. Formerly this dust- laden water was allowed to run as waste into the nearest river or lake. _ The most improved method of re- claiming the solids in the ‘“‘scrubbing”’ water, a method used in many modern plants, consists in conducting the dust-laden water into a shallow, coni- cal pit about forty feet in diameter. A vertical shaft, suspended from a steel framework, reaches down to the bottom of the pit in the center and slowly rotated by a two-horsepower engine. To the lower end of that shaft several arms are attached, to which paddles or scrapers are fastened at such an angle that they tend to scrape the solid par- ticles, which are deposited as mud, to the center of the pit. The deposit is scraped into a re- ceptacle at this point, whence it is pumped to a tank, in which it is mixed with the dust collected in the ‘‘settling- chamber.” The mixture is pressed into briquettes, which are smelted with the iron ore. POWER SHAFT B. Popular Science Monthly A Machine for Splitting Logs in Two F you wished to break a stick jn. half, you would probably put your foot on the center of the stick and pull at the ends. Following somewhat the principle of this natural method, Albert Hunter, of Spokane, has invented a machine. for splitting logs. A chain, fastened to one end of a cross-head, is brought down the side of the log to be split, carried acrosg the end and up the other side, and is then fastened to the near end of the cross-head. Jutting through an opening in the cross-head is a wedge blade. The back end of this blade is attached to a threaded bar carry- CHAIN TAKE-UP GEAR DRIVE 4 AND CLUTCHES. ) a The log to be split is chained to a cross- head, and a wedge blade is forced into it by a gear-driven threaded rod ing a pinion wheel which engages a train of gearing. When the gear is revolved the bar moves forward, forcing the blade into the log. When it has gone its full length, the gear is re- reversed. An ordinary engine is used. A Fish and Its Scales Are Soon Parted OW do you scale a fish? With a knife, probably; but it took you quite a while to learn how, and the job is at best a messy one. Mr. Harlan A. Perry, of West- boro, Mass., tells us of a better way — by using the fish-scaler which he has recently in- vented. It looks like a bath-brush and is operated like one; but in- stead of bristles it is studded with metal spikes. These spikes are flexible enough not to tear the fish’s skin off with the scales. The frame that holds the spikes is made in two sections, spaced a small distance apart. The spikes are This fish-scaler is built like a bath-brush, but has movable spikes instead of bristles 44 inserted in holes in the lower one; their heads keep them from slipping out. But the spikes are constructed to move through the short dis- tance between the lower and the upper frames, which are likewise made of metal. The novel construc- tion and constant movement of the spikes tend to make them yield in every direction, so that, in addition to removing the scales from the fish, they are also practically self-cleaning. The young man. in the pic- ture is using the scaler on a big fish, but it can be used on small ones as well. a |e ee ee, ies ee, ee ee

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is 1, it g d 5- of - ~) 1t yf : ‘Geptember, 1919 Under the Ice to the Pole In a wonderful submarine that feels its way under icebergs with the help of a blind man’s stick By Simon Lake Sooo RBoN 5 R. LAKE hardly needs an introduction to readers of POPULAR SCIENCE MONTHLY. He is a pioneer inventor and builder: of sub- marines, creator of the ‘“‘even-keel submergence” type of submarine. To hear Lake tell of his early struggles is to make one wonder why inventors are regarded as white crows. When Lake, as a young man, would fight his way into the office of a bank president and try to borrow money with which to build a submarine that would run on the bottom of the sea on wheels, the pres- ident would think to himself, ‘“‘Another crazy inventor!’? When Lake went so far as to say that he would provide his submarine with a compressed air- chamber out of which a diver could step upon the bottom of the sea without letting in a drop of water, the president would look around uneasily and’ surreptitiously press a button. Lake did build that submarine. What is more, it had a compressed-air chamber by means of which divers actually left and entered the submarine under water. Today Lake is one of the foremost submarine builders in the world—an expert who is consulted by most of the great naval powers.—EDITOR. HEN I think of the long, W painful struggle with the ele- ments, the hardships, the pri- vation that have attended the dis- covery of the poles and that still attend polar exploration, I wonder why a scientist deliberately enters the frigid zone with an equipment that has been ridiculously antiquated for at least twenty years. The news- papers speak, very properly, of a “dash” to the pole. A dash it must be if the goal is to be reached during a few favorable weeks over ice and snow. Must Be Reached by Strategy The ice-bound region is approached strategically, as if it were a field forti- fication on a battlefield. Year after year Peary toiled over hummocks and eluded treacherous crevasses. Polar exploration has always meant blinding snow-storms, living on dog’s meat, disease, and death. All this is un- necessary, to my mind. Polar ex- plorationis under- taken primarily for scientific pur- poses. Yetthevery circumstances that attend these ‘“‘dashes’’ are against painstak- ing scientific work. That the poles have actually been reached, that we know a little of polar life, that the general con- figuration of the earth around the poles has been very roughly sketched, is little short of miracu- lous when we consider the terrible hardship that has been endured. All the privation and suffering, all the ice-bound months in the black arctic night, could easily be avoided if the submarine were employed for arctic exploration. Think of Nansen covering three quarters of a mile a day for eighteen months—delayed by open water and slush-ice in summer, and by intense, gnawing coldin winter. Then think of a submarine traveling comfortably, even luxuriously, under the polar sea at the rate of a hundred, perhaps even two hundred miles a day, coming to the surface at will, making its scientific observations in the thor- ough, leisurely fashion that always characterizes scientific investigation, and bringing back with her after a few months a veritable encyclopedia of information that could hardly be gathered by the ordinary means in decades. What will the Esquimos say when they see the polar submarine bobbing up from beneath an ice-field ? 45 ‘Simon Lake But is it possible? Arctic explorers think so. Captain Scott Hanson, who was a member of Nansen’s expedition, enthusiastically endorsed the plan that I drew up. Latterly Mr. Vilhjal- mur Stefansson, one ofthemostintrepid of arctic explorers, has taken an in- terest in the possibilities of the sub- marine. Let it not be supposed that any un- derwater craft may set out for the polar seas and boldly plunge under the ice when she can make no further prog- ress on the surface. Only a vessel especially designed to cope with the . peculiar conditions that prevail under arctic waters may be safely employed. The Polar Submarine At the suggestion of Captain Han- son, I designed a polar submarine that would probably meet the require- ments—a vessel that embodies all the knowledge that I have acquired in operating under- water craft under circumstances fully as trying as those that must attend arctic ex- ploration. Any plan for voyaging to the poles must de- pend, for its suc- cess or failure, on the extent of the ice-covered areas and on the depth of theice. Asub- marine cannot travel indefinitely under water. Its storage batteries must be recharged —an operation that is carried out at the surface.

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Moreover, the air-supply of the crew is limited. Thirty-six hours is about as long as a submarine may remain under the surface. Hence the area covered by the sea ice must nowhere be so great that the submarine is pre- vented from coming to the surface within that time. The depth of the sea ice is important, because even the stoutest submarine built for the Navy is not designed to withstand the tremendous crushing strength of the water that prevails below two hundred feet. - Can It Break through the Ice? Mr. Stefansson assures me that open water is encountered more fre- quently in the arctic, even in winter, than is commonly supposed. When it is coldest, an arctic explorer finds every twenty-five miles water that is either actually open or that is covered with ice thin enough to be broken by a hammer blow or by strong pressure. It follows that the arctic ex- plorer in his submarine is in no danger of being suffocated because ice prevents him from coming to the surface and re- newing his fresh-air supply. But will not a few inches of ice offer obstacles in rising? I have found from actual expe- rience that a submarine is an excellent ice-breaker. It is easier to lift ice than it is to break it down in the manner pursued by ice-breaking steamers. I have designed a special form of ice-breaking submarine which will be easily able to cope with ice much thickerthanthe comparatively thin sheets of which Mr. Stef- ansson has written tome. My submarine, the Protector, fitted out in 1903 for experimental navigation under the ice, had an inverted toboggan or a pair of runners built up over the conning-tower. It was easy for her to lift eight inches of ice and to break into open water. What of the depth of an ice-pack? Wind and wave pile cake on cake, until a huge congealed mass is formed. Does it extend below the critical two hundred feet beyond which submarines of today may not descend lest they be crushed like eggshells? Here again Mr. Stefansson reassures me. It has been his experience, confirmed by Peary, that one hundred and twenty feet is the probable maximum depth of the irregular projections that hang from the comparatively level surface of sea ice. Clearly the margin of safety is ample, when it is considered that two hundred feet is easily attainable by present submarines. Imagine yourself in a submarine under the arctic ice. Suppose that your craft suddenly strikes a great, pendant, jagged mass of ice. What then: Will not the outer shell be punctured? Clearly, some way must be devised of either seeing or feeling one’s way. Feels Its Way Like a Blind Man Seeing is out of the question. Even assuming that the polar waters are free from sediment and therefore re- markably clear, it is impossible to see more than forty or fifty feet ahead— a distance so short that a disastrous collision with downwardly hanging ice is inevitable. There is but one solu- tion of the problem. The submarine must feel its way. A blind man taps his way along with a stick; his onward progress is a series of experiments in feeling. An insect has its antennae. ne ees rea: ati’ 3 AEE get eee “SURFACE ICE AIR DRILLS ie # BE PACKING Beis ot oo A Be BEARING The polar submarine would be provided with an ice- cutter—a tube extending up through the submarine and operating chisels or drills Something like the blind man’s stick or the insect’s antennae is wanted. The necessary feeling devices were invented years ago, and tested—not, to be sure, under the ice of the polar seas, but under conditions very simi- lar. My first submarine, the Argonaut, could not only swim like a fish, after the fashion of any submarine of today, but also run over the bottom on wheels. When I used her as a kind of under-water automobile, I would regu- late her buoyancy so that she would run over even the softest mud without sinking in. {ndeed, I found that she would readily mount and glide over a 46 by compressed air Popular Science M onthly © giant rock. Fearing that I ‘might some day run into an under-water cliff or into a sunken ship and smash the lookout windows in the bow, I re- built her with an overhanging nose which could be collapsed without ad- mitting water into the main hull. — But, what is more to the present. purpose, I provided her with the very blind man’s stick that must be used if the submarine is to be employed in polar exploration. The Blind Submarine’s ‘‘Feeler” What was this blind man’s stick, this ‘‘feeler’’? Nothing more nor legs than a telescoping bowsprit. At the inner end of a heavy six-inch pipe was a plunger that could slide into a cylinder perforated so that the sea- water could enter and: leave. The operation is obvious. When the bow- sprit collided with a rock the plunger was forced back into the cylinder and the force of the impact expended itself in driving the water out of the cylinder through the perfo- rations. Thus a simple and effective hydraulic cushion was provided. But, it may be objected, suppose the object encoun- tered was lower than the bow- * sprit? I provided a ‘‘nerve” that met the situation—a steel wire rope that ran from the end of the bowsprit down under the forefoot of the submarine. The _ bowsprit was held in its extended posi- tion by brass plugs screwed through the top walls of the pipe ram and cylinder. When the Argonaut was running on wheels over the bottom and the wire touched an obstruc- tion, she would rise, because she was so nearly buoyant, andslideover. If she met an obstruction, head-on, the bowsprit then would shear the brass plugs that held it in position, and slide back, shutting perforation after perforation in the cylinder. Thus the vessel would be brought gradually to rest. Crawling Under an Iceberg Here, then, we have the very mech- anism that would enable a polar sub- marine to feel its way beneath pendant ice. I would improve it, however. At the outer.end of the bowsprit feeler I would mount a wheel. Thus equipped with a wheeled sprit;the craft could climb the side of a precipice, so long as the propellers were running. Why this should be possible a naval architect will understand better thana layman. The naval architect will ex- plain to you that the distance between

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ito of ‘in she fo- nd ion he si- ed he en ¢ on nd 1¢- ise nt, an he ar k, er be st. SSP NpqongygQN gaa Fog TOFD a: RF FB EER BB Wi the center of buoyancy and the center of gravity of asubmarine is only a few inches. Hence the wheel at the end of the bowsprit is several feet above the center of buoyancy. Assoon as the sprit-wheel touches a vertical wall, a back pull is exerted several feet above the center of buoyancy of the vessel. The bow is lifted and the en- tire hull rotated slightly around the center of buoyancy. It is astonishing how little effort is required to make a submarine lift herself over rocks. In the Argonaut we rarely knew when we were mounting obstructions. There was no shock, and only the depth- gages told us what was happening. Overcoming Natural Conditions Once I even “hurdled” a _ small wreck in the Argonaut. In the Gulf of Finland I navigated my wheeled Protector over a bottom that was rougher, harder,.and more uneven than any ice-pack is likely to be. In a distance of less than one hun- dred yards I encountered variations of forty and fifty feet in depth. Since ice hanging down from above is to be avoided, the “‘feeler’’ of the Argonaut would be reversed. The collapsible bowsprit would pro- ject directly from the foreioot, and the wire nerve would be strung from the top of the bow to the axle of the contact wheel. The accom- panying illustration of a submarine traveling under an iceberg shows how the worst possible conditions may be readily overcome. Through thick glass ports in the bow and in the conning-tower the condition of N CII llddldddddttdddddddddsdiss SISO SE0 8g yp’ Wl" "=F DR DG BEF SSS Two positions of the submarine as it approaches an ice-cake. Her periscope is first lowered. She reduces her buoyancy toa few tons. The wheel and inclined guides at the bow cause her to run under the edge of the ice. She dives under the ice at a slight inclination and comes to a level keel again as soon as she secures a bearing on the reverse toboggan placed just over the center of buoyancy. On the left the submarine is. shown charging pack-ice. The guide wheel at the end of the bowsprit, the ice as the submarine is sliding under a berg can be noted. I used searchlights on the Argonaut, but searchlights would be of little advan- tage if there were much sediment in the water. Under the Ice on Wheels From this account of my experience with the Argonaut and of the simple inventions that can be used to grope one’s way beneath the polar ice, it becomes apparent what type of sub- marine I would advocate for arctic exploration. She would be a 500-ton vessel, with a surface speed of about twelve knots and a radius of action at ten knots of about six thousand miles. Her maximum speed submerged would be ten knots. Five knots is a more economical speed; her sub- merged radius of action would then be — When this telescoping bowsprit collides with a rock, the plunger is forced back into the cyl- inder, and the force of the impact expends itself in driving the water out through perforations 47 or feeler, which is held in its extended position by compressed air, touches the vertical hanging wall of the iceberg, and it is pushed back into its cylinder to a degree depending on the submarine’s mass and velocity. The bow is dipped down, the inclination depending on the weight of the mass, the distance between the centers of gravity and buoyancy, the thrust of the propeller, and the distance between the line of the thrust, center of buoyancy, and center of gravity of the ship about two hundred miles. Her hull must be strong enough to withstand the pressure of the water at a depth of three hundred feet—strength easily attainable when it is considered that a depth of two hundred and eighty-five feet has been reached with United States Navy submarines. She must have the usual hydroplanes and depth- control rudders, and she must have the ‘feelers’ that I have described in order that she may grope her way un- der the ice. Wheels, too, she should have, so that she can run along the bottom, as I did in the Argonaut. Out through the Ice Since such a polar submarine is intended to fulfil a scientific purpose, I would provide her with a compressed- air compartment by means of which a diver can step out on the ocean floor, collect samples of marine life, and return again. The pressure of air within the compartment would keep out the water. The diver would find no more difficulty in stepping out upon the sea and back again than he’ would in entering or leav- ing his house by the front door. Lastly, I would provide an ice- cutter, a simple device consisting of a tube which can be extended up through the submarine and which will serve to operate chisels or drills by compressed air. Through the tube fresh air could be drawn in while the vessel is still under the ice. By means of a larger telescopic tube a hole can be bored through the ice big enough to permit the crew to climb out.

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BASKET GOAL - BASKET GOAL Human animals performing in this cage get all the sensations of a boxing bout If You Must Fight, Fight a Ball HE curious-looking structure shown above is the home of a new game invented by Timothy Daly. The cage is about twenty-five feet long, twelve feet wide, and eight feet high. The roof is solid, but the side walls are made of one-inch slats, so there is plenty of fresh air. At each end of the cage are pockets for the balls. You and your opponent take positions at each end of the enclosure, one of you bounces the ball and gives it a punch in the general direction of the opposing goal, and the game is on. The ball must be kept always in the air after being put in play, and he be who first punches it through his = *>: \, opponent’s goal scores first blood. ae Some of the long stems of this seaweed are hollow and tough. This fact is well known to the small boy on the Maine coast, and he has dis- : covered that the stem can be j used as a siphon. After a storm in which the fishermen’s dories on shore have been filled with rain or flying spray from the surf, it is the job of the small boy to bail out the boat. First he collects a lot of long kelp stems, and after draping them over the side of the water-filled craft, sets them all working as siphons by the primitive method of sucking on the outboard ends of the snes TEA To Prevent Damage When the Fly-Paper Flies T’S an ill wind that blows curtaing into fly-paper and fly-paper to the carpet; for the glue on fly-paper ruing other things almost as completely as it ruins flies. That is why the holder shown in the picture below has beeninvented. It isa wire frame bent so that a sheet of fly-paper will fit in it snugly. Curtains and carpets will hit the wire instead of the glue. What is this glue? Resin. And what is resin? It is the yellow gum q This wire case for fly- : paper will protect the every available curtains and carpets when ; inch of space be- stems until he gets a flow of Here is a man who beat three hundred women! water running through each. Don’t be alarmed; it was only in a canning contest 48 i o Popular Science J fonthly mm " that you see often on the bark of trees, secreted by the tree through special resin canals. Alcohol will draw this resin prema- turely out of most plants, and since a large amount of resin is used commer- cially, this method is often used. Fresh resin is soft and glue-like; but it will harden gradually when exposed to air. But when it is used on fly- paper the flies usually fill up ' ; the wind blows; but of fore the harden- Hollow seaweed stems : ’ x make very good siphons if psatiga we eg cg ing takes place. for bailing out water ” 9 © Let Seaweed Bail the Boat He’s a Champion Preserver N the beaches along the coast of Maine, where the LMHURST, on Long Island, New York, a town rich in tide rises much higher than on parts of the coast farm-land, had a canning contest. The contestants, He farther south, great quantities of a heavy brown sea- composed of three hundred women and a few men, grew all 43 weed, commonly known as “kelp,” are washed ashore. the vegetables that they put in the cans which were entered in the contest. Who won? Oneofthemen! His name is Charles Rundquist, and he is shown herewith surrounded by many of the vanquished cans of his rivals. Virtually none of these vege- table-growers knew anything about farming before the days when the national cry became food conservation. They did _all their planting and growing in war gardens, and found it so profitable that they have de- cided to keep it up. In fact, Mr. Rundquist and many of the others live in apartment- houses and do their farming on fifty-by-twenty-foot plots a short distance away.

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‘taing O the ruing letely r the V hag bent >in it Il hit And gum see the Crees, 7 the ugh esin cohol this 2>ma- t of nts, large resin mer- shis often resh and but ‘den vhen air. n it fly- flies up able > be- den- lace. hin nts, y all vere Vho His list, vith his ge- ing ays ime did ‘ing t so act, of nt- -on eptember. 1919 Don’t Lose Your Head or Your Hat NYONE who has, in a high wind and a high temper, pursued his ‘errant headgear down the street will be interested in.a new hat-fastening ‘device. All you have to do, with a hat of any ordinary, common-sense construction, is to insert in the sweat-band at the front or the sides of the hat a light metal plate conforming to the shape of the hat and having a comb hinged to it at a variable angle, making it easy to slip into the hair. Fastened to ‘each end of this plate, again at dia- “metrically opposite points in the back ‘of the hat, and passing through a barrette, is an elastic band which may be easily concealed. Insert the comb in the hair, gently pull the hat down to a comfortable position, arrange the barrette—and there you are, ready for any old-gale that blows. Or, if you prefer, dispense with the barrette and use any number of these special combs elastically secured at any desired point in the hat. COMBAND pais FASTENING /.i- & BARRETTE k AND ELASTIC FASTENING A simple, comfortable, and inconspicuous device for keeping your hat on Why They Weren’t Working T was not a bank holiday, so why weren’t the Rolls-Royce people work- ing? This question was heard in Derby, England, on June 16 last. The answer came, proudly, from the workers themselves that they were having an extra holiday to celebrate the first non-stop transatlantic flight. And why were they specially interested? Be- cause they had made the two engines that safely propelled the Vimy Vick- ers airplane on its big trip. The flight was made in fifteen hours and fifty- seven minutes, with an average speed of 117% miles an hour. If you have a greenhouse you can ripen your vegetables and fruits indoors when cool weather comes F there are green tomatoes growing in your garden when autumn comes, pick them and put them in the green- house. They will ripen in a few days. That is the advice which Mr. A. J. Copelin, of Chicago, gives; and, judg- ing from the number of tomatoes in his greenhouse, ke ought to know. In picking them he left at least half an inch of stem to prevent rotting. These tomatoes were perfectly green when they were taken to the hothouse, but they will come out red and ripe Off to the Hothouse He picked the largest tomatoes first, and by the time they had ripened the next lot had grown into their shoes. He kept picking tomatoes until the frost came. Then he gathered up the vines them- selves, brought them in, and planted them in the ground beneath the hot- house. And still the tomatoes grew; in fact, they kept it up far into. the winter. Getting Ore from Mine to Furnace T the present time approximately seventy million tons of ore are mined and fed by gravity into the great fleet of vessels at Duluth that carry the ore around the lakes, through the iocks, and on to the blast-furnaces. Modern efficiency demands that vessels carrying this ore sball unload within sk One end of a large traveling bridge that loads and unloads vessels for carrying ore 49 a few hours, so that a quick return trip may be made. To aceomplish this great speed in unloading and loading, large traveling bridges are erected at the docks, permitting grab buckets of fifteen tons ca- pacity to enter the hold of the vessel, fill themselves automatically, and deposit the ore on docks or cars. These unloading bridges are gigantic structures several hundred feet in length. To move them, wheels having maximum bearing power are required. Chilled iron wheels are best fitted, because the chilled metal has no malleability and does not flatten or distort under loads of two hundred thousand or three hundred thousand pounds per wheel. The highest concentrated load on wheels in railway service is about thirty thousand pounds. Concentration as high as one hundred and twenty thousand pounds per wheel are entirely permissi- ble; in fact, the limit of load is the point where the chilled iron wheel forms a depression in the rail. | |

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Everybody’s Wearing "Em Goggles were not designed for the use of the motorist alone “Let them kick up the dust, what care I?” says horse No. 3, for he is wearing goggles. Thus he will: be able to’ see his: way clear past the horses ahead

Popular Science M. onthly

According to this strange man, water in the eyes is worse than water in the ears; he protects his eyes with goggles, while he allows his ears to stand out beneath his diving-cap

Locomotive engineers as well as automobile drivers have become goggle-eyed because of wind and dust

Goggles likewise ward. off the heat that rises when electric riveting takes place Even the Eskimo is learning that it is no longernecessary to bind his eyes in order to pro- tect them from the glare of the sun on ice and snow; he finds that goggles of col- ored glass are much better. Of course the white explorer had to teach him the trick

a An aviator’s nose is about the only part of him that braves the elements above. Otherwise goggles cover the smal! part of his face left bare by cap and collar SS ee - as <

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‘September, 1919 ROPE TS ri, « $8ekaa Sg, ee We often hear and see the word, especially now, when we read in the newspapers that the World’ War will cost something like two hundred billions of dollars; that Germany’s indemnity is twenty billions. For the financier the word has a definite meaning. To him a billion dollars represents just so much purchasing power; he knows just how much effort is required to collect it. But what does a billion mean to you? Well, take the Brooklyn Bridge— one of the engineering wonders of the world—as a basis of comparison. Thirteen long years were required to build it. Thousands of lives went into its making. It cost twenty-one million dollars. Yet with a billion dollars we would have sufficient to build forty-eight Brooklyn Bridges Here’s another way of comprehend- ing a billion. Suppose that.in the summer of 1870 a paying teller had started counting out one-dollar bills. Counting at the rate of a hundred ‘and fifty a minute, and working eight hours a day, three hundred days a year, allowing for Sundays, holidays, and a_ short . vacation, he would have handed out his last bill in the summer of 1916. It’s lucky we don’t own a billion. Think how many people we should have to employ to keep it counted What’s a Billion, Anyway? It’s not easy to comprehend, but these pictures may help you om Pgs ae ee SRY a: sehen depelysneece calla t mame ect hs Sree. ~ EG: t oe mene st ihe hs tet __

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An extension foot that holds fast is a better ladder sup- = port than.is the a unreliable brickbat ~

A Good Ladder Foot Saves Legs * HE inventive idea,” says the in- ventor of this ladder attach- ment, “was the application of a posi- tive adjustable member to a ladder leg. A screw was the best adaptable device that I could think of,:and so I con- centrated upon the application of a lifting-jack to a ladder.” The sliding attachment for the leg is controlled by a thumb-nut of sufficient length to allow for the required adjust- ment. Teeth that bite into the sup- porting surface are located at the bottom or foot portion of the attach- ment and prevent slipping. On the other leg of the ladder is another foot-plate, also provided with teeth, but this support is fixed instead of being adjustable. * The movable foot slides in a suit- able guide-way, which insures the needed adjustment with the least possible lost motion and wabbling. Not only can the device be attached to ladders, but it can be used in connection with scaffoldings. The ‘painter and the builder often have difficulty in securing a good foothold for their scaffolding, for the brickbat so often resorted to has never proved very reliable. The device described would therefore seem to have a widely extended field for usefulness. The weight is but slightly over five pounds, and the only tool needed for attaching is a screw- driver.

N making cutters, gages, files, and all small -tools, magnetized iron is never used. When these tools are held in magnetic chucks for any length of time, however, they nearly always be- come slightly magnetized. The re- sult is that they gather unto them- selves many small chips of steel and iron, and lose their keenness and some- times even break. The remedy for this is a tool-de- magnetizer. One is shown here. A cutter is being demagnetized. The workman holds the cutter over the three powerful poles of the machine, which pull the molecules of steel in the cutter out of their regular mag- netized order. The theory of magne- tism is this: every mole- cule of iron or steel possesses a positive and a negative pole. [If all of these molecules in an iron bar are arranged so that their positive poles “a point in the same direc- tion, and consequently their negatives do like- wise, the bar becomes a magnet. But when the

Popular Science Monthly | <-* Taking the Magnetism Out of Tools

By holding the cutter, which has accidentally become charged, over three powerful magnetic poles, the workman demagnetizes it molecules are in no regular order mag- netism is not evident. Acertain amount of magnetism exists in all iron and steel. But iron and steel enter the magnet class only when their magnetic powers are great enough actu- ally to draw up less powerful pieces. New Thrills in the Movies ET us suppose we are witnessing a photo-play of the war. A loco- motive puffs into a station behind the lines, whistle shrieking, bell ring- ing. Soldiers alight and march away, their hob-nailed shoes clumping on the cobbles. From the distance comes the deep-toned reverberation of cannon. All these noises, and more, are produced by a machine invented by Frank Ilo, of Dallas, Texas, Briefly, Gis a ot ee COMPRESSED OPERATED BELLS the machine is an assembly of many sound-producing instruments unified through a central electrical control; more specifically, a series of shafts, belts, and pulleys, diaphragms covered with buckskin, revolving cylinders partly filled with water or with lead shot or steel balls, wooden beams and slats, flexible sheets of tin or other metal, air-valves, whistles, bells, etc., to be used at the will of the operator.

Here’s the machine that reproduces dramatic sounds called for in the action of a play, from echoing thunder to the fateful ringing of a doorbell 52

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September, 1919 A Modern Magic Mirror S it stands on the store counter the mirror shown below looks like any other face-reflecting glass. But ~ as you approach to adjust your tie your features suddenly fade out, giving place to a many-colored electrically lighted sign. You begi mirror. An inch or so behind it is a pane of glass on which beautiful colors—usually carry- ing an advertisement—are etched. Behind both there is an electric lamp, backed by metal reflectors. When the light is not turned on the mirror alone shows up. But when the light flashes, the ad- vertisement glows through the mirror in an unusual, many times repeated effect. An automatic flasher causes the light to flash on and off continually. You’re looking at this advertisement when, Q sar presto! it turns into a mirror; then it sud- denly changes back again. It is really nothing more than two surfaces of glass spaced apart with a gasket, behind which there is an automatic on-and-off light The Brick IR ISAAC NEWTON may or may not have discovered the laws of gravity be- cause of an apple that fell on his head; but we may be sure that Charles H. Brisbin invented an earthquake- proof brick because a brick fell on his head during the great San Francisco earthquake. He told us so himself. One side of the Brisbin brick has two ring-shaped bosses, while the opposite side has two ring-shaped depressions opposite the bosses. When laid in a wall the bosses fit into the depressions, locking the bricks together, either lengthwise or crosswise. The Brisbin brick is of the same size as the ordinary building brick, differ- ing only in that one side of it is con- caved and the other convexed. This feature makes it absolutely self-bond- ing and interlocking. After a wall of such bricks has been built no brick can be removed unless all the bricks above it are taken out or a chisel is used. The interlocking brick promises to n to read, and have just about mastered the message when its words vanish and you find yourself staring into your own startled eyes in a looking-glass as strange as the one that was Alice’s gate to Wonderland. The front of the sign is a platinum-plated, translucent PLATINUM FILM TRANSPARE LETTERS PLATE GLASS MIRROR He is building a chimney out of the earth- quake-proof bricks which he has invented 53 In many cities conveyances take crippled children to school, that their education may not be neglected By sending wagon libraries to out-of-the-way towns our edu- cational bureaus are gradually bringing up the literacy average For Better Education HE honors for literacy must, alas! go to Germany, where the illiteracy percentage is far less than one. England ‘follows close’ behind. United States nearly six per cent of the people can neither | read nor write our language. This sounds bad, but it really isn’t when you consider our heavy immigration. Educational bureaus throughout the country are con- stantly bettering conditions; for greater literacy means greater labor production. In many counties traveling libraries are sent out—wagons fitted up with book-shelves. But careful education of the children is the most important branch of all; and so many cities provide conveyances for crippled children to go to school in. When we consider that India and Egypt are over ninety- two per cent illiterate,our fast decreasing six looks very small. that Is Earthquake-Proof be particularly suitable for hollow walls, since it can be used as an absolute bond reaching But in the from one wall into the other, tying course to course in an earthquake- proof structure. In the building of chimneys the interlocking brick is again choice ma- terial, since it can be used as a binder to avoid cracks, which have in the past been the cause of countless fires. The new brick has a great many advantages. It can be laid more easily and quickly and with less mortar. No wires, nails, or broken bricks need be used in connection with it. Since the brick is concaved, the heat in the kiln reaches the center of the mass of clay more quickly and the burning is accomplished in less time than by the old method. Several large brick-manufacturing plants in California and Arizona have already equipped their machinery with dies for making self-bonding bricks.

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Popular Science M onthly Making Crystals Speak Not alone do crystals speak in this new science, but phonographs are operated and gun explosions measured “By Lloyd E. Darling S a producer of electricity, at least one : A of the old-timers-—-the crystal—has been brought out of the museum and laboratory class. In a lecture recently given before the New York Electrical Society, Mr. A. M. Nicolson disclosed some re- CRYSTAL ye TRANSMITTER \\ markable studies be had just made into / } Li the properties of certain crystals, notably Rochelle salts. Curiously enough, these crystals, | when subjected to a pressure of polly sia, ene ae: several pounds and agitated, are 60 HEAD RECEIVERS €0 HEAD. RECEIVERS quite capable of furnishing an elec- Circuit for illustration above. The crys- tromotive force of as much as eight tal is its own battery. In its ride over a volts, enough to operate an inde- record currents are heard in receivers finite number of telephone receivers CRYSTAL ELECTROMAGNETS in series. If a vacuum-tube ampli- fier is inserted in the circuit, natu- rally many more receivers can be controlled. Mr. Nicolson uses this ‘‘piezo-electric” effect for an ee eee uncommon kind of telephone. Going out of the room, and talk- ELECTRON STREAM FILAMENT PHOTOGRAPHIC ing in close proximity to one of his PLATE crystals connected to telephone re- Seis ceivers at the ears of his listeners in How Sir J. J. Thomson uses crystals to the manner shown in the diagram, record explosion effects. Explosion (not he is able to make his shown) jars crystal, Currents generated charge plates’ and de- speech plainly heard. No flect the electron stream battery is necessary. The sound waves striking the crystal agitate it suffi- ciently to preduce the nec- essary currents: Conversely, if a_ tele- phone’ transmitter and a crystal are connected as shown at the top of the TERMINAL WIRES whats" | | | ——— Listening to phonograph music— rendered by a crystal-reproducer in another room, out of hearing The transmitter may even be taken out of the circuit and another crystal substituted, whereupon the arrangement will work, particularly if a vacuum tube be inserted in the circuit as an amplifier. If two crystals a are near each other and electrically connect- ed through an amplifying tube, a slight jar will start one to send- ing currents to the other. This will cause the other to give off a sound; the sound will, of course, agitate the first crystal more, and increase the effect. Presently both crystals will be making noises at each other. A curious “talking together” effect results. It is analogous to the whistling sound sometimes obtainable by holding an ordinary telephone receiver ad- jacent to a telephone transmitter, the interactions being the same. If a needle be inserted in one of the compression plates of a crystal and allowed to ride over a phonograph record after the manner of an or- dinary reproducer, the selection on the record may be made audible in telephone receivers with great fidelity — all this - without all the customary diapbragms of reproduc- ers, or the batteries ordi- narily found in telephone circuits. That certain crystals, : Showing the method of affix- opposi crystal : : - when compressed, woul aA Re oe went i act as a loud speaker. The ing terminal wires. The cen- emaieads peas Fo d haw a A _reproduce whatever paper screen acts as a dia- ter of the crystal is of one ee is said in the transmitter. hragm, vibrating the air polarity; the ends, the opposite known for many years. | phragm 54 ——

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of d, ed Is t- e, d- ‘is off e, 1d at g id 1g j- r, ‘September, 1919 ** Piezo - electric effect” is the MICROPHONE TRANSMITTER i 6VOLT term usually ap- -_ DRY : : = ces plied to this a phenomenon. =. TRANSFORMER ‘*Pieso’’ : 100: 200000 comes from the Greek piezein, meaning ‘‘to press.” The “pyro-elec- tricity’”’ of the ancients, CRYSTAL qe though de- eee | rived primar-_ gRCEIVER 5 ily from heat- BaD SPEAKER ing, was of Because electric this general currents will cause nature... Mr. a page ang Nicolson’s crystal to vibrate, it will “speak” when work consists addressed through in gett ing the microphone something somewhere near practical out of this old phe- nomenon. And surely he has suc- The investigator clamps his crystals between aluminum disks in the man-— ner made clear in the illustrations. Pressure is applied by means of the thumbscrews. During this process electricity is given off, the voltage rising as the pressure increases. There- after, if the crystal and its framework be agitated in any manner, as by the tick of a watch, or by a voice, or by anything whatever, a potential will appear between the electrical poles of the crystal, the potential being dependent upon the pressure under which the crystal is operating, the ticks of the watch or a similar sound producing the give maximum variation of the piezo potential. Ten kilograms per square centimeter (about one hundred and forty pounds per square inch) causes the saturation point to be ‘reached. A. M. Nicolson and the Rochelle-salt crystals. The large one weighs over two pounds. In his fingers is a seed crystal. Properly treated, it, too, will grow large Mr. Nicolson grows these crys- tals out of jars full of saturated solution of the salts, starting with a small crystal as a “seed.” That is, if one takes a small crystal of Rochelle salts, or almost any other salt for that matter, and places it in a saturated solution of the same sub- stance, leaving it undisturbed for hours or days, the small crystal will grow into one infinitely larger. One of the illustrations herewith shows the Showing two meth- ods of making crys- tal-reproducers for phonographs. At the left, rubber bands provide com- pression; at the right, springs do it potential at every tick. Eight volts is a com- mon potential so ob- tained. Torsional or twist- ing forces, applied to the crystal while un- der compression, also produce the potential. Left- hand torsion, for instance, causes the aluminum disks at the ends of the crystal to take on a negative charge, while a strip of tinfoil, or girdle, held in place with rubber bands around the middle part, takes on a positive charge. In practice about two kilograms per square centimeter of a crys- tal’s cross-sectional area are ap- plied lengthwise of a crystal by tightening up the springs holding the aluminum disks shown in the illustration. This pressure is, roughly, twenty- eight or twenty-nine pounds per square inch, and seems to Listening close at hand to a crystal-reproducer. cally, the customary phonograph horn is not necessary 55 investigator with one of the hugest crystals he has grown in this manner. This one weighs over two pounds. Mr. Nicolson’s work has been pro- ductive of much that is interesting. Sir J. J. Thomson recently an- nounced before the Royal Institu- tion in England investigations of somewhat similar character. But, instead of having experimented so much with telephonic applications, he suggests that a good method to get practical service from piezo-elec- trics would be to use the crystals to measure instantaneous pressures in the explosion-chambers of guns, gas engines, and similar appliances. Knowing exactly what goes on with- in a gun or a gas engine makes possible designing them for maxi- mum efficiency, a highly desirable end and not always obtainable at present because of the limitations of existing measuring appliances. According to Thomson’s plans, a tourmaline crystal, properly en- cased, would be exposed to the ex- plosive pressures to be measured. A suitable small pocket at one side of the explosion chamber might make this possible, or in the case of guns the barrel might be prolonged, and the extension utilized for the mounting of the apparatus in an effective way. Owing to the fact that the voltage given off by tourmaline is directly pro- portional to the pressure to which it is subjected, and that the voltage al- most instantaneously responds to this pressure, in the opinion of Sir Joseph, a crys- tal would be an excel- lent medium for meas- uring explosions of 1/30,000 to 1/50,000 of a second in duration, such as frequently occur in guns and gas engines. Under this plan, the apparatus would be connected as shown in the figure near the bottom of page 54. A hot filament gives off an electron stream in vacuo, asuitablescreen holding back all buta narrow beam of electrons. This beam passes between two metal plates ca- pable of being charged by po- tentials resulting from pressures applied to the crystal during ex- plosions. These potentials are naturally directly proportional to the degree of pressure the ex- plosion inflicts on the crystal, and the electron stream will therefore be deflected by the charged pletesin an exactly cor- responding amount, registering on the photographic plate because an intervening barium Waiaie~ platino-cyanide coating or such, makes its path luminous.

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Popular Science Monthly ,

There’s Always Something: Attachments designed to promote

; This tube is said to elimi- A truck with a water-tight body and special suction pump, nate punctures. Under used for cleaning sewers and carrying away refuse, is compression it closes when here shown pumping fresh pohd water to a water-tank the nail is withdrawn

The inner-tube air-releaser is a handy little tool. It holds the air-valve down until all air is exhausted. This tool will pay for itself many times over

DIRT CLEAN OUT PLUG The water-seal’ air-cleaner allows

The horn button is used From coast to coast cars

only clean air to enter the carburetor Ve Ve Ne er 4 m he ? : S 4 a" A a

Now. comes the automatic socket wrench, which re- duces to a minimum the time for removing and replacing engine bolts. It can be operated from any position all-trades. Quickly attached and detached is the power-transmitting contrivance that turns the car. into: a veritable jack-of- It can be belted to almost: any machine

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cp AY ye yyy Wap

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Popular Science M onthly * _ Getting Ready for the Next Earthquake Profiting by her terrible experience of 1906, San Francisco intends to be fully prepared one aspect of earthquakes largely settled now. A short time ago the city completed a huge ‘“‘four- stacker” pumping plant capable of de- livering twelve thousand gallons of water per minute into the fire mains, and that at only a few minutes’ notice. The plant is there to put out earthquake fires. “In time of Sn FRANCISCO thinks it has By Lloyd E. Darling walls and interior of the building run struts and braces. The engineer who laid out this building figured that although the heavens themselves may fall his structure will stand. In orderto secure satisfactory opera- tion in the hurry and confusion that is likely to prevail in an emergency, the interior machinery is of a simple type. The number of parts requiring atten- warm the others up in a hurry, while at the same time a fire is being worked up on their grates. Maximum steam output may thus be delivered to the pumps in a short time. When Next the Heavens Fall So when next the heavens fall, and the earth shakes, and buildings shud- der and totter and collapse in peace, prepare for war,” says San Francisco. “In time of no earthquakes, prepare for the day when the earth shakes.” Back in 1906, three hundred million dollars’ worth of prop- erty was burned in a few days be- ‘ Cause an earth- quake shook down buildings and started fires. A large part of that loss might have been pre- vented had not the earthquake also succeeded in disjointing the pipe-line that connected the city’s water reservoirs with the fire mains. So now the city has built this new pumping plant down in the heart of the industrial and old fire- swept district, so that in case of need it will be there to transact an immense amount of business in a short time. The Plant Is Earthquake-Proof You may think that an earthquake that shakes down buildings may shake down the pumping plant too, and thereby reduce the whole idea to zero. Not so. This building is of steel frame and reinforced concrete con- struction, absolutely fireproof, and the roof is so substantial that it can with- stand the impact of falling chimneys, cornices: of buildings, brickbats, and anything else that the surrounding neighborhood finds it advisable to deposit thereon while the earth is quaking. Steel shutters may be pulled down over the windows if the bombard- ment is too heavy. All through the ad ted a In order to fight a con- flagration such as that caused by the earthquake, San Francisco has built a great new pumping plant in her business district tion or adjustment has been reduced to a minimum, and the design and ar- rangement are such as to render it improbable that an error on the part of an operator will necessitate. the shutting down of any considerable portion of the station. Two inde- pendent cast-iron discharge-pipes from the station to the city’s seventy-two miles of water mains are laid, one on each side of the building, so that an accident to one will not involve the other. Not Dependent on One Pumping Unit Several pumping units have been provided rather than one large one, so that, if anything goes wrong with one of these, all the plant’s pumping “eggs,” so to speak, will not be in one basket. Steam is maintained in part ofthe boilers at all times, ready forthe emergency. The piping is such that live steam from these boilers may 58 San Francisco’s streets, business will be done as usual in this particularstruc- ture. The fires under the boilers will speedily be put under forced draft, the en- gineer will start the first of his pumps to “chug, chug, chugging,” able steam in- creases, due to the exceeding activity in the boiler-room, he will commission the other pumps. Shortly the big pulsating throbs of water coming from this plant will be felt in the mains throughout the city, ready to argue with fires. There will be no need to go to rail- road tracks somewhere about and get fuel, for five concrete tanks at one side of the plant contain enough fuel-oil to operate the boilers at full capacity for ninety-six hours (four days and nights). It is the same way with the boiler water supply; for six more tanks beneath the floor hold a million gallons of fresh water, ready for quick use at any time. The water that the big pumps in the engine-room of the plant send into the mains, however, is salt. The reason for this is that San Francisco Bay is handy, and, as everybody knows, there is plenty of salt water in the ocean. A _ reinforced concrete tunnel comes up from the bay, ter- minating-in a sump under the pumps, as seen in the drawing. If the operators have to stay in the plant any length of time during an emergency, there is a kitchen provided, so that they may cook their meals. All these conveniences make for max- imum efficiency in times of grea emergency. “ and as his avail- -=*

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September, 1919 No Packing or Gaskets on These Cast-Iron Pipe Joints OST cast-iron pipes used to carry water, gas, sewerage, exhaust steam; or dye and acid by-products have joints that have to be securely closed or fitted by means of packing, gaskets, or a poured lead compound. The labor expended in making these joints air- or fluid-tight is the most expensive part of the work, and has led engineers to devise a type of universal pipe and joint which does not require the use of packing, gaskets, or lead to make the joints. All that is necessary are two wrenches, white-lead paste, bolts, and nuts. The joint is-iron-to-iron, only white . or red lead being used to make it up. There are bulbous rings at each end of each pipe length, together with two or more ear lugs cast integrally with the pipe proper. The adjacent ends of the pipe being made up fit into each other on a machine-taper- ed end of about two degrees on the spigot end and about two and one half degrees on the hub end. The ear lugs at each = end of the pipe 9 ---====25:====--¥ are lined up and amworseajene f bolts inserted through them to draw up the ends The molten metal compound is bailed out of the large kettles by means of ladles and is poured into the molds; several kinds are shown below

During the operation of combining the component metals in the melting-kettle, the molten mass must be thoroughly stirred and freed from the oxide scum that rises to the top of the hot metal The Tinsmith’s Glue and How It Is Made HAT glue, nails, brads, and screws are to the cabinetmaker, the joiner, carpenter, and wood- worker, solder is to the tinsmith, the canner, and the scores of other kinds of metal-workers.:. Just think of the - millions of tin cans and other metal containers that are manufactured every year and that are used for the air- tight packing of preserved foods; the square miles of tin enn roofs; the hundreds of miles of eaves and gutter-spouts; the countless tanks, kettles, boilers, stills, and tubes of tin we weer it loo The pipes are laid end to end, and the bolts or galvanized iron that are made every year. < inserted in the lugs with their heads point- In the m e-products thousands of ton of the pipe. ing oppositely; the bolts are then tightened anufacture of these:p , 8 of tons of solder are required. It is made in the form of sticks, bars, or wire, and forty or more establishments in this Comb Your Hair and Cut It Too country are engaged in its production. There are many OU need a hair-cut. So you go to the barber shop, wait till the barber is ready for you, then climb in the chair, get your hair cut, and some perfumed hair tonic you don’t want. You discover, when he is through, that he has done awful things to the back of your head and that the price of hair-cuts has gone up. Why don’t you cut your own hair? Not with the scissors and a bowl, as your mother used to do, but with a cutting comb like that shown here. On each side of the teeth there is a razor blade, held in place by a clasp. The edge of the blade reaches down to within a very short distance of the end of the teeth. To cut your hair, simply start combing, holding the comb in an upright position for the long hair on top of your head. As you come down the sides and back, flatten the comb gradually until it lies flat against your head when you reach your neck. You will soon be able to manipulate it to suit your taste. When the blades grow dull you can change them. kinds of solder. They are divided into two principal groups: soft solders, which have a melting-point of 200° Fahrenheit or lower; and hard solders, the melting-point of which may be between 200° and 600° or more. Soft solder consists of lead and tin in different proportions, while the composition of hard solder varies considerably, according to the purposes for which the solder is intended. Copper, zinc, aluminum, cadmium, silver, and other. metals, in addition to lead and tin, enter into the composition of hard solders. The metals, in their proper pro- portions, are thoroughly mixed and melted in large crucibles or kettles. When the solder, after long stirring, has reached the proper consistency, it is ladled into molds by which it is shaped into bars of certain standard shapes and weights. The process

of manufac- ture is . clearly il- As he combs, razor blades, lustrated attached one on each side in the pic- of the comb, cut his hair. tur at the The cutting comb comes é - : neatly packed in a case top of this of either khaki or leather page. 59

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aes INSEE ST a A Sea oes

Were | ianinh <_ bs TANK

A specially constructed waterproof bag into which a victim of caisson disease is placed for recuperation Bagging the Diver to Save His Life * HE diver wriggled out of ‘his complicated suit, and was walking around, when suddenly a sharp pain shot through his head and his left arm felt curiously numb. Caisson disease! The dread of all divers. He was promptly thrust into a bag, which was sealed and pumped up with compressed air until the pressure in it was the same as that under which he had been working only a few minutes before. Then the pressure was gradually low- ered to normal, and about an hour later the diver was taken out of the bag completely cured. ’ This bag for divers was invented by Hermann Stelzner. It is made of strong waterproof cloth, which, when de- flated, may be rolled up so that it occupies very little space. Thus everywhere the diver goes the bag may also go. Up near the top of the bag there is a glass window through which the diver-may look and be looked at. The lid of the bag is made of metal, and when closed down renders the bag absolutely air-tight. . This lid is provided with a pressure-gage, a safety-valve, a blow-off cock, and means for connecting the bag with compressed-air cylinders and an air-regenerating device. Caisson disease is caysed by the too sudden return of the diver: to ordinary air-pressure after he has been working under very heavy pressure. In the first place, as he is lowered into the water the air- pressure in his suit must be in- creased to equal the pressure of the water outside. Thus an extra sup- ply of oxygen and nitrogen is forced into his blood. Blood will absorb the oxygen, but not the nitrogen. It forms little bubbles, and these must be foreed out very. gradually.

This lifelike creature was made on a typewriter from dollar signs 60 Popular Science Monthly, Do You Get the Point? VERY time you change a record, change your needle— that is one of the laws of the talking-machine. And the discarded needle? inexpensive that it really doesn’t count. But consider the thousands of people who are throwing with you and the combined amount of steel thrown. The waste then appears enormous. Daniel W. Causey, of Norfolk, Va., has invented a machine that will eliminate part of this waste. It is a needle- sharpener, and in it a worn needle may be revived four or five times. Mounted on a stand is a rotary disk. This disk is divided into three sections: a sharpening surface, a polishing surface, and an outside cam. The needle-holder is ad- justable and has at its end a wheel that touches the rotary disk and revolves when the disk is turned. You insert the needle and move the holder so that the needle is near the outside edge of the sharpening surface. Then you turn the handle on the right side of the machine, and the disk and needle revolve. As the sharpening goes on the needle moves across the disk, gradually working its way backward until it strikes the polishing section of the disk.

A worn-out talking-machine needle is being sharpened and polished in this machine; it will come out fully revived By this time it is sufficiently sharp. As the polishing goes on the holder wheel reaches the adjustable cam, and this imparts a rocking movement to the needle-point and rounds it off to the desired radius. Of course, all these mo- tions are carefully regulated in the machine. It takes about twenty seconds to perform the entire operation. Drawing Pictures on the Typewriter ON’T be too sure, when you hear your typist industriously hammering the keys, that she is working hard. She may be turning out your mail, and then again she may be punching out dollar-sign giraffes, as this typist is doing. The combination of curves and straight lines found in a dollar sign is also found in animals, so that the dollar sign gives the best results. Eyes, ears, and shadows are in- dicated by striking over the same dollar sign several times. If you want to try this and don’t like giraffes, you might make cows, roosters, butterflies, or even girls. First you outline in pencil your favorite animal, then fill in the dollar signs. If your ribbon is half red and half black you can give him red eyes or a red ribbon round his neck. If dollar signs make you nervous, try the letter S.

You throw it away; it is so small and :

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T Re f.09 ct > eee, ’ * ay " September, 1919 It Helps You to Keep Away from the Dentist ONSIDER the shape of your teeth—how they grow. They are close together in curved formation, and are therefore very hard to n. ron have tried a tooth-brush with even bristles and also a tooth-brush the bristles of which are shaped to fit the outside of your teeth. But how about the dark, hidden, inside spots? They often decay from neglect, for you simply can’t reach them with the ordinary tooth-brushes. The tooth-brush shown herewith was devised to clean out just those dark cor- ners. Its back is curved up hook fashion, so that the end bristles nearly meet. Miss Gladdis Rohr- bough, of Omaha, is the inventor of the contrivance. The picture shows you how to use the brush, though of course you will not have to take out your teeth and jaw- bone in order to do it. A tooth-brush curved like the one shown here will clean the inside of your teeth thoroughly A Small Tent for Smail Boy Scouts F, in spite of peace leagues, there should be a war twenty years hence, the Boy Scouts of today will be well prepared to fight it; for they live as nearly as possible the soldier’s life. The young Boy Scout in our picture takes with him on his hikes a pup-tent. It is just about large enough to cover him comfortably when he stretches out on the ground beneath it to rest or sleep. Then, when he goes on his way, he C ®, rolls the tent up and fits it into a case that is easily carried. The tent itself is made in one piece, open at one end and having a fly at the other. It can be put up or knocked down in a minute. The Boy Scout move- ment is doing an immense amount of good to city boys. The gangs that formerly terrified peace- ful citizens are fast turn- ing into orderly groups organized under scout- masters. They drill the boysregularly, teachthem healthful games, and take them on long hikes into the country. SoA c hie, - The ingredients are dumped into a cone-shaped hopper, which swings up. over two other hoppers. Through an . adjustable opening the mix- ture pours from one. hopper to another, becoming. thor- oughly mixed in the operation by a _ self-kneading process Here Is a Concrete-Mixer that Works Like TOWER 3H} BUCKET jj x S The Boy Scout gets lots of comfort from his pup-tent When the tent is not working it is rolled up and put in a case, much like an umbrella 61 ELEVATOR HOIST WATER. MIXING | HOPPERS 4 riveted to a tall wooden tower. LEVER: ARM DISCHARGE HOPPER. . ee | CHARGING nOpPER an Hour-Glass N automatic concrete-mixing machine, that works on the same principle as an hour-glass, has been found very useful for the construction of foundations, dams, road-beds, and in fact for all of the uses to which concrete is applied. In the accompanying photograph the apparatus is shown making foundations. Into a revolving mixer on the ground various ingredients are poured and dumped into a cone-shaped hopper. At the outer end the hopper is attached to two long arms which are When the hopper is full it is swung upward on the elevator, by means of a cable and pulleys, to a position directly over two other cone-shaped hoppers. An adjustable opening in the bottom of the movable hopper allows the mix- - ture to pour out into the cone beneath it, from there into the third cone, and from the third cone into a chute, down which it tumbles into a crude elevator, which lifts it in a wooden structure to the desired point. A self-kneading process takes place in each of the three hoppers. The walls of the cones are constructed at such an angle that the concrete will not slide downward through the opening, but will roll inward and flow out like the grains in an hour-glass. After this operation has taken place three times in succession, the concrete is uniformly mixed, the sand, stone and cement being in a nearly homogeneous state. | |

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Popular Science Monthly. Rubber on Its Way from Tree to Tire P * YON be long before they are rolling on State roads

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nthly. ~ rns na a September, 1919 It fits well around the neck, though the trousers seem rather baggy. But consider the diffi- culties of trying to sit down without having them tear! And while he cuts the coat sleeve out, his helper bastes up the trousers On with the trou- sers! They boast of pockets four, while the coat and: vest have but three each. -Three and a half yards -of paper vill make the suit Pistend You're a Bundle and Wear Manila Paper Suits Harry Sussman is trimming off. the edges of a paper lapel. He is a New York tailor who makes wrapping-paper suits that will last three days— if, meanwhile, it doesn’t happen to rain 63 He looks like thirty cents—the approxi- mate. price. of the paper, pins, thread, and cement used in his suit; he will feel even. cheaper if he gets wet When basting proves that they fit, the seams are fas- tened with cement Even. though his careful work will survive but three days’ wear,~ the tailor cherishes the hope that stronger paper will soon be manufactured

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Popular Science Monthly How “Doug” Keeps ‘Fit for. the. Movies OUGLAS FAIRBANKS,. who was the originator of “‘pep’”’ in motion pictures, doesn’t worry about hotels and restaurants while he is combing the wild and woolly plains of the West for suitable locations for his photo-plays. He travels in a “house” car that was designed and built for him. - It is a strange but cozy looking vehicle, the walls of the car forming beds when they are let down. There is additional space inside the car, as well as a complete kitchenette, ice-box, electric lights, and all the conveniences of home. No wonder his plots are original; ; 4 for, lying out in his bunk at night = = ———— beneath the great Western canopy, The oil-barrel is pushed up the in- he naturally thinks of big things. Mo seve Gummer of dhart cleceite cline, the bung taken out, and from oil-soaked wiring if you adopt sufficient oil poured out to fill the new timin ’ g system. It takes the containers on the floor below only a few minutes to _ install Keep the Oil Upstairs A New Ford Timer T seventy-five cents a gallon, HE ordinary timing sys spilling automobile engine tem or commutator fur- lubricating oil is expensive. nished on the Ford car is With ground-floor space in placed low.down at the front garages worth more than that end of the engine, where it 3 ne upper et ~ is very likely to get dirty wows vom very noms in the with oil, grease or water and way on the main floors. thereby impair its successful Both of these problems were operation. met and overcome in a large To overeome this difficulty, private garage in New York a Minneapolis concern has va .. the horse ge eg recently brought out a new type _iunnel-shbaped chute was of timer, which is connected to provided on the top floor, and the the cam-shaft of the engine at the full barrel of oil rolled up on top of same point as the ordinary com- . the chute by means of permanent mutator, but in which the new iron skids. A pipe led from the base cf This explains why Douglas Fairbanks is . i) co - ‘the funnel, down through the floor, to alwaysin fineform. He travels comforta- a wd ee a three tanks set up close to the wall on _ ly in his specially designed “house” car way up the height of the radiatod the floor below. A detachable swivel . as shown in the illustration at pipe was provided, so that the two end tanks could be filled. the top of the page. This Non-Elevator Garage Makes Use of Grades HANKS to the fortune of an ideal elevation, a Washing- ton, D. C., hotel-owner has con- structed a three-story garage that eliminates all elevator service. Three direct doorways approach the varying floor levels, and hotel guests are enabled to enter or leave as quickly from the third floor as from the first. The garage has a storage capac- ity of five hundred cars, one floor offering accommodation for dead storage to one hundred cars. The approach from the street’ direct to each of the floors is*made possible by the hillside arrange- Three distinct levels—made possible by taxing advantage of a hill—permit the ment shown in the picture. motorist to drive directly into the garage without the annoying wait for an elevator €4 ata. = thes, aa

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September, 1919 Combination Farm Tractor and Motor-Truck S the progressive farmer replaces his horses with motor-driven farm tractors, he finds that there is considerable haulage work from his farm to the near-by town which the average farm tractor cannot do, partly because of the damage that the cleated tractor wheels do to roads. Very often he cannot afford to buy the motor- truck, and must therefore keep several horses to carry his goods to market. However, a wide-awake tractor manufacturer has now produced a tractor with a wide range of possible speeds and an extra set of metal wheels with solid rubber tires. With.such a machine there are no exasperating delays occasioned in trying to get rusted cleats off the wide tractor wheels, for it is much easier to take off the tractor wheels entirely and replace them with the solid-tired wheels. This tractor hauls loads of from five to ten tons, in one or more trailers, without the slightest damage to the roads and at a speed of from eight to : 7: ten miles an hour—much faster .. than a farm-horse can travel. 1 To prove the feasibility of both of the claims for the new tractor, a tractor 1er and trailer outfit recently. left New York on a cross- sys- country trip’ to Los fur- Angeles, Cal. The r is tractor. was ront equipped with the e it solid rubber-tired lirty wheels when it and started, and pulled ssful behind it a four- wheeled trailer, ilty, also on rubber hee tires, in which the Ready at an instant’s notice to take the road ype d to ic _ Improving the Motor-Truck Clutch “a OTOR-TRUCK clutches that grip too quickly, when the — clutch pedal is released, throw the entire weight of the hali truck and of the goods in the body upon the engine suddenly, - with the result that the latter wears out quickly. A quick engage- ment of the clutch likewise causes sudden strains on all parts of the transmission mechanism, including the gear-set, driving-shaft, and rear axle members. Oil cannot be placed on the clutch surface material to ease its action, because oil will make the clutch slip. Many devices have been employed to overcome the harsh or the slipping clutch. The new method here LEATHER CLUTCH- shown has given good aan results. The method makes use of small lengths of clock- spring, bent to about half the radius of the clutch rim and then ; inserted between the , SPRING rim and the leather : facing of the clutch. These are placed be- tween therivets hold- ing the clutch facing to the rim. , The springs should Taking the jumps out of a truck is accom~ be inserted — well plished by inserting clock-springs between under the rear edge the rim and the clutch leather facing of the clutch rim. 65 FLY-WHEEL CLUTCH CONE’ “Adaptability” is this steel mule’s middle name. It can easily be converted into a truck or tractor at will. The wheels are changeable farm wheels and plows were carried, so that the caravan might stop at different points and dem- onstrate its ability in farming work when desired. The substitution of the farm wheels for road wheels is done in much the same fashion as wire wheels are changed on automobiles, and the tractor may be taken off ‘the road‘and put to work plow- ing-in. the extremely short space of twenty minutes’ time. Test the Cylinder Compression by Inserting a Tire-Gage in the Pet-Cock FTER the auto- mobilist has had Em TIRE GAGE the valves of his engine ground, one of‘the best methods to determine ‘the thoroughness of the ACORN- SHAPED work is to test the RUBBER PLUG compression in the cyl- : inders. But how? If the job has been prop- erly done, none of the air inside the cylinder can leak past the valves, and it will be harder to turn the en- gine over than would , be the case if the Attach the tire-gage to valve did not ‘ seat the priming-cup and see properly. So it is what the engine compres- necessary to find the sion is in that cylinder compression in the cylinders in terms of pounds per square inch. The only accessory for the car that can mea- sure pressure is the tire air-gage, and a clever Chicago merchant has brought out asimple device that makes use of either of the two types of tire- gages now commonly in use to find the cylinder compression, without a special form of pet-cock. ry wey” TOP OF CYLINDER — =

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Popilar Science Monthly Housekeeping Made Easy Little things that help lighten the labor of the housewife HUH He A OIUN Ha ti PAM “Betty Broom” is shown here all dressed up to protect her from the rough handling of daily use. Her dress is patent leather, Kitty is made of a very fine grade of steel wool... She is found useful for cleaning nickel and brass or for scouring any metal QS TT Here is the baby that lived in a shoe. The giant shoe foldsupcom- pactly and the shoe crib can be taken out into the fields so that the baby may have her nap in the fresh air i Discarded inner tubes. from-the auto- | mobile make excellent shoe-soles. If they ; are properly attached,—and anybody can MUDUALMMULEL ’ Peeling onions is a solemn occasion in every household. .Why not take the automobile goggles from the automo- bile and. wear them while peeling on- Me 7 % A learn: the trick,—even walking ‘around ions, so they will not make you weep: a wet golf course will not loosen them 4 4 g 4 g el Put the eggs on the fire, set the appa- PERFORATED ratus on a near-by table, and when BOTIOM the eggs are ready a bell will warn AIR you that they are done exactly right pee — wa ti HOT WATER, SPACE, So When the cow browses in green pastures No, it is not an egg-beater. Only The knock-down features of this kitch- her taste is not so discriminating as to sepa- a tiny, tiny drill that bores holes en stool reduce the shipping charges and rate the tares from the wheat. Hence in broomsticks or other pieces of make it possible to store the stool in this machine, which purifies the milk hard wood for inserting a hook a small space when it is not needed 66

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The ‘‘toolmaker’s knée”” permits the operator to turn his work to any angle, thus making sure to get the part he’s working on in the most convenient position QMOiAAANHETHDWHHHA_A_-QqWwOMBWWVspa_y_y WWD With this machine this young woman counts thousands of pennies every minute. It stops automatically at a bad penny Manufacturers say that the new chisel steel can be made so hard that it will cut glass. The picture above shows it forced through a carbon steel block lected Me with Tools and Machines Speed up the work and at the Same time save your energy A new machine so designed that it will perform the two operations of tearing up and loading street pave- ment on to a car pulled behind = oA NAN P me SLA NANT One of the new de- velopments is a tool steel that is cast di- rectly, into .the shape of the tool or die de- sired. ~ . It! possesses the unusual quality of not changing size The dial gage is little, but there is no measuring prob- lem too difficult for it to master was: Whi We Me lecccc HOM NOMWOKOKIKINN AMV wy q3aq4>DWaP yg gaa AAA AVP f This equipment will bore any gas-engine cylinder for automobiles, tractors, trucks, stationary engines, and does it in jig time SOLDER £{ BQ ae lela Mt MM MLL Met Pa When a tool has been removed the telltale rack shows its outline in red. A rack of this sort prevents the continual loss of tools 67 With the heat applied directly to the . point where it is needed, and only during the time necessary, this solder- ing-iron consumes only about one tenth of the energy that is generally required

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Popular Science Monthly Rescuers Must Carry Their Air with Them ANG! A coal-mine explosion. In a very few minutes a rescue squad had started down. They were curiously equipped, as the illustration below shows. They carried lamps in their hands and tanks on their backs, and over their faces they wore masks. The lamps lighted their way, the masks protected them from the poisonous fumes of carbon monoxide and carbon diox- ide gases, and the tanks supplied them with oxygen to breathe. These men could not have used ordinary trench gas- masks, which simply filter the air breathed in. For down in the mines there is little air to be had, ard the rescuers must bring their own supply of air with them. Coal-mine explosions are often caused by the ignition of coal-dust floating in the air. The explosion makes a temporary vacuum, and this is followed by the breaking of the walls and the inrush of poisonous gases. These gases cause great trouble when rescue work is being carried on.

Less perfect than McAllister’s “Escaping from Sing Sing dummy, but none the less Prison, John McAllister left effective, was the headless this lifelike dummy behind dummy built by Jean Kirsher him to mislead the guards The Dummies They Left Behind Them EEPERS at Sing Sing Prison say that the use of a dummy to aid a prisoner to escape is as old as the prison, and that celebrated its ninety-fourth birthday not long ago. Cleverest of all the dummies that prisoners have left to represent them is the one made by John McAllister, —_ a burglar who escaped from Sing Sing on June 13. The rescue squad is going down into the coal-mine; every McAllister molded a head from dough mixed with man carries on his back an oxygen-tank, which will supply soap, producing a clever copy of his own features. He him with air; he also carries a lamp and wears a mask decked the crown of the dummy’s head with hair cut from his own, using a coarse, artificial crop only for the less conspicuous sides and \ na ee ee ea em back.. A glance at the picture will show served as a blasting - machine you why the guards were fooled. and caused this first-class explo- Another ingenious dummy was the sll fe Pre co game prenehorn creation of Jean Kirsher, who es- mobile used in the emergency caped from the prison three years ago. Kirsher wasn’t able to build a head and face for his double, but he stuffed a pair of trousers and shoes, propped up his lay figure with legs crossed, and laid a newspaper against them. From outside the prisoner appeared to be reading quietly.

They Forgot the Blasting Machine OLSHEVISTS' watching their charges and were ready to connect the bombs explode before they escape charges to the blasting-machine, the in their car! Certainly that seems to machine was not to be found: it had be the tale of the picture to the right, been left behind. but ’tis not so. It is true, though, Rather than waste time going back that the men are responsible for the to get it, the men decided to try to exvlosion shown above. detonate the shots by using the The men were sent out to blow upan_ batteries of their automobile. They - ey: — old house which was directly in the touched the leading wire from the The finishing touch — to the bat- > < A = ; % Q tery—that blew up the house. These path of a water-pipe line being laid. charges to the car’s batteries, and in- dangerous looking men ‘are merely After they had placed the dynamite startly the charges exploded. carrying on their regular work 68

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‘September, 1919 Keeping the Anchor Quiet TARTLED by a pounding sound at the bows, the watch officer shouts: ‘‘Lay forward and secure that anchor!’’ Then he mutters something about the adjectived thing going adrift whenever the ship hits a ripple. The same anchor that held the ship safe when, with its flukes stuck firmly in the bottom, it was doing an anchor’s duty, sometimes becomes an actual menace when it is hoisted to its resting place at the bow while the vessel is under way. Stockless anchors—that is, anchors without the cross- bar through the shank and having their flukes pivoted to the shank—were an improvement on the old-fashioned type, but they did not fit snugly against the bows of a ship. This bad ‘“‘housing,” as the seamen call it, was especially marked in modern fast ships, which are very “‘fine’”’ forward and consequently have their bows slightly hollowed. John Taylor, of East Boldon, England, noticed these things, and he has invented an improved stockless anchor. in which each fluke has independent play. Each of these flukes can be adjusted independ- ently, and fixed in posi- tion in such a manner. as to fit snugly against the side of a ship. Mr. Taylor believes that his invention will do away with the necessity for recessing the bows of ships or for having castings especially fitted to receive the anchor flukes. While the fluke at the right is lifted, the other drops down. This independent action en- ables the flukes to fit snugly against the ship’s bow The upper picture shows the amplifying horn that shouts your clay-pigeon score; the lower one explains where the voice comes from—a man located in the pigeon shed near the traps Scoring the Clay Pigeons You Shoot RACK! You shoot at a clay pigeon, and behind you a loud-voiee-booms your luck. Whence comes that voice? From an amplifying horn which is connected to a telephone in the pigeon shed, along- side of the traps. From that point a man can see best the result, and he calls the score off in his one-way telephone. The device is used by the New York Athletic Club. A Day’s Shopping Delivered by Airplane BUNGALOW bed, a floor lamp, a fireless cooker, three pillows, some curtains, napkins, table-cloths, towels, a taboret, a carpet-sweeper, a percolator, and a rug are being tucked into the observer’s seat of the Curtiss air- plane shown in the picture below. Somebody is evidently going to sleep, cook, clean, and trial flight will develop into a regular delivery airplane ser- vice. But customers of the store that send home goods by airplane will have to have large back yards or live near obliging golf courses. Every day new uses are being found for airplanes. For some time now there has been a regular airplane mail ernment is plan- ning to send airplanes out to drink coffee. The aviator? No; asuburban customer of a_ service between New York and Washington; and the gov- large New York department- store. The air- plane is play- ing delivery wagon. This airplane made the thirty-mile flightfrom store to house in twenty-five minutes, landing on a golf course near by. Since one airplane can S ‘carry all of Beant ships at sea in order to collect incoming mail. Passenger ser- vice is already in effectin many parts of the world. But us- ing airplanes for delivery wagons is quite a new thing — though an airplaneonce carried a piano from London to these things, perhaps this The airplane is getting a tryout as a delivery wagon for a large depart- ment-store; it is loaded with merchandise for an out-of-town customer 69 Paris. But will it pay?

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Popular Science Monthly A Country House and Garden on Top of a Skyscraper THIRTEEN-STORY apartment hotel is about to be erected in New York, and on the roof of this hotel there is to be—what? A three-story Colonial mansion having twenty rooms, seven baths, a garden, pergolas, balconies, and countless flower-pots! We had thought of renting this “country home in the heart of the city’’ when = , completed. But the rent—! A trifle of $30,000 a year. ay Cie f We retire chastened to our modest apartment. 7 / We wish we had that $30,000. Fancy, an elevator Ha Wee cer / traveling at six hundred feet a minute, twice the speed of i ve t= a | / the ordinary apartment-house elevator, to take us up to “i Via | ‘sh us our new home from the ground floor of the building any ie ida Vy time we liked. And then, the southerly and westerly |. exposure, with every room open to the light and air! A grand stairway leads up to the second story of the house, In a most businesslike fashion the A-4 landed two guests on the roof of a Cleveland hotel Will Dirigibles Land on Roofs? DIRIGIBLE sailed from Akron to Cleveland, Ohio, recently, landed on the roof of a hotel, deposited two passengers, and fifteen minutes later cast off and sailed back to Akron. Sounds rather tame, doesn’t it, after the thrills of a transatlantic air race? And it looked rather tame, too, to the thousands of Clevelanders who saw the great gas- bag, 160 feet long, come gracefully to rest on a little thirty- foot platform built on top of the hotel’s electric sign. But ; : it was the first time in the history of aviation in America A Colonial mansion on a New York roof. It has a ‘ : twenty rooms, seven baths, a garden, sleeping- that an airship was successfully landed on a roof in the porches—all at a modest ciniae Geom of $30,000 heart of a city. The two passengers were Ralph H. Upson, an aero- and of the seven rooms and: six baths on this level (what nautical engineer of Akron, and Major C. H. Maranville, would we do with six of ’em?) the smallest room is ten by flying instructor at Wingfoot Lake, an army balloon fourteen feet. On the third floor is a large studio, twenty by school near Akron. thirty-one feet in size, where we would think up new ideas The dirigible left Akron at 5.30 P.M., and, fighting a for the PopuLAR SCIENCE MONTHLY; the studio has a strong head-wind all of the thirty-five miles to Cleveland, pitched ceiling, giving the room that atmosphere which we was soaring over the hotel roof at 6.36 o’clock. Twenty- now so sadly lack. five students from the flying-field had been stationed on According to the real estate prophets, New York is soon the hotel roof to handle the big “‘blimp.” to be graced with other structures of this character. The airship circled the roof several times before nosing up to it from the windward side; but When the Bell Rings Spee d U ’ p the Separator treacherous air currents were encountered, and the airship was swept away before the anchor ropes could be cast out. The machine circled around and made another attempt, VERY dairyman knows that, to but unsuccessfully. obtain the best results, the Then Pilot James Schade tried circling crank of a centrifugal cream-separa- round past the hotel and letting the tor must be turned with considerable balloon drift over, using the power of speed. The invention here shown the propeller to head it into the wind indicates when the speed falls below and bring it to a standstill just over the limit of efficiency. the landing platform. A steel bell is attached to the gear Not until the seventh trial was the end of the crank-shaft, revolving attempt to land successful. Then the with it. Inside of the revolving bell carriage of the dirigible was brought to is a hammer lever riding on a cam. a perfect standstill above the landing When the crank is turned slowly, platform, several anchor ropes were one fork of the ham- cast out, and in a few seconds the big mer.lever drops into bag had been hauled down to the a slot in the cam at platform and securely lashed. every revolution and Two curious objects hung below the causes the other fork to ring the bell. If the’ a bell is quiet the speed rings Steeve is right. one &Lever ear. They were cylindrical air-inflated af the wieke at the coon buffers, which kept the car from bump- separator falls below the point ing and breaking the propeller. of efficiency, a bell 70

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wa | ee cel wre Ss September, 1919

Getting More Out of the Gas Engine _ One of the most remarkable inventions of our engine using both steam and gas time—an Be ies that has noticed the steam that issues from the top of a radiator on an automobile or motor-truck. To generate that steam, heat has been wasted. And then the exhaust—how much heat is wasted when the burnt gases are discharged! Is there no way of utilizing the energy thrown away in heating the cooling water and in the exhaust, no way of getting more out of the gas or the gasoline engine? The patent records bulge with pro- posals to use all the jacket and all the exhaust heat in raising steam in a small separate boiler for the purpose of driving air auxiliary steam engines. A proportion of the heat can be use- fully recovered from the exhaust gases; but the cooling water from the jacket is of little value, its temperature being too low. But suppose the tempera- ture of the cooling water could be maintained at that of steam at useful pressure? Surely the efficiency of the engine would be improved. That is what William Joseph Still, an English inventor, has done. The Still engine is both a combus- tion engine and a steam engine. The charge of gas and air is admitted on one side of a piston and exploded; then the piston is driven back again by steam- pressure on the other side. Never before has such an en- gine been de- signed and con- structed. Using Engine’s Wasted Heat The unutilized heat of the gas engine is made to play the part of a fire under a boiler. It heats the water in the jacket of the cylinder, and the jacket in turn forms part of the circulat- Ta paren ing system of a steam boiler. Hence the cool- ing water enters and leaves the jacket at a con- stant. tempera- ture, regulated eal the piston up. of the circulating system of a boiler. by the pressure of the steam. Cooling is ef- fected by converting the water into steam without raising its temperature. All the waste heat that passes through the walls is thus usefully recovered in the water as steam. During compression the incoming charge ab- sorbs heat instead of los- ing it, because the walls are at steam temper- ature, and during com- bustion and expansion the uniform and higher mean temperature of the walls reduces the heat lost to the jacket water. Some of the heat thus economized adds to the useful work on the piston, the balance passing out in the exhaust gases for recovery. Part Played by Exhaust Gases The exhaust gases play a minor but alsoimportant part. After raising their quantum of steam, they are employed in preheating all the water required for the steam generated in the steam and STEAM TO ENGINE <<———_——_— FINALCOMSUSTION ( AXKAUST

# In this remarkable invention—an engine that uses both steam and gas— the piston first sucks in a charge of gas and air. : . charge drives the piston down. Steam-pressure on the other side then drives boiler gives a The steam is generated by making the water-jacket part The exhaust gases are used to preheat the feed water. The primary object of the system is to use it in improving. the conditions under which the cylinder must work, and thus to attain the maximum efficiency of the fuel burned within it, 71 William Joseph Still, the English engineer who has the efficiency of the developed a combination gas engine The explosion of the jacket water and in the boiler. Still’s primary: object is not to use the waste heat for raising steam, but first to use it in im- proving the heat condi- tions. of the working cylinder. and so make sure that he is getting the most from:the fuel burned within it. In Still’s engine the steam on one side of the piston actually increases penn sears ness explosion operation on the other side. What is more, the explosion operation on the gas side increases the efficiency of the steam side. There is no condensa- tion, no loss or waste. In the Still engine twenty-nine per cent additional brake horsepower is added to the shaft of the engine with- out increase in the fuel consumption if the steam is not condensed. Forty per cent is added if a condenser is used. The steam generated by the heat re- jected by the combustion of gas warms the engine before starting. The steam generated starts the engine against load, if necessary. More- over, the use of steam makes it possible to run at any speed from zeroto maximum for any period— something long desired. Starting is un- affected by at- mospheric con- ditions. Power at normal loads is developed by combustion and steam from waste heat alone with an efficiency of at least twenty- five per cent aboveany known combustion en- gine of similar proportions. Ad- ditional steam generated by a fire under the large range of overload with- out serious loss saving heat in efficiency.

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Popular Science M. onthly . Finding Your Way Among the September Stars “Job’s Coffin’ and other interesting things that are to be seen in the sky this month HE evening skies for September begin to give promise of the coming of the : winter constellations. The circu- lar star map shows us the Pleiades rising about 9 P. M. at the middle of the month. By the following month Taurus will be rising at that time in the evening. T he constellation—or rather constellations— chosen for special study this monthare those of Delphinus and Aquila. Delphinus, the Dol- phin, is sometimes referred to as “‘Job’s Coffin.” It is easily recognized by its small parallelo- gram, with the added line toward the south from the western corner. It is rather isolated, and may readily be picked out by looking a little to the south of the zenith along the meridian at the middle of the month. Looking in the same general direction, \ the group should easily be recognized at any time during September. Ofthe stars inthegroup, twoare seen as doubles in a small instru- ment. Alpha, the upper right-hand star of the parallelogram, is a double of magnitudes 4 and 9.5, and is widely separated—thirty-five seconds of arc. One second of arc is the angle subtended (by three inches) at the distance of 1 mile. Gamma, the upper left-hand star of the parallelogram, is not so widely separated, but it is a very beautiful pair of stars, one yellow and the other bluish green, magnitudes 5.5 and 4.5, separated by about twelve seconds of arc. The Bright Star in Aquila To the west of Delphinus and a little to the south lies Altair—the bright star of the constellation Aquila, the Eagle. The con- stellation may be recognized by its forma- tion about Altair. The latter may be recognized by its bright companion star, a couple of degrees above it. Altair is one of the nearest bright stars in view in the northern heavens. It is situated only fourteen light-years distant. It is moving with a proper motion of .65 seconds of arc per year; that is to say, it moves about one degree in 5,540 years. As this is a relatively fast proper motion, it is easily seen why the stars are spoken of as ‘fixed.’ Aquila is in the Milky Way, and as a consequence the sky at that point is an interesting sight in a small telescope or opera-glass. It was in Aquila—just to the south and west of Altair—that the By Ernest A. Hodgson The Star Map for September This map represents the appearance of the sky at the times listed below. It is specifi- cally arranged for the latitude of New York, 40 degrees north, but is practicable for ten degrees on either side of this latitude. August 7, midnight. August 15, 11:30 p. m. August 22, 11:00 p. m. ‘ August 30, 10:30 p. m. September 6, 10.00 p. m. September 14, 9:30 p.m. September 22, 9:00 p. m. September 29, 8:30 p. m. October 7, 8:00 p.m. October 15, 7:30 p. m. October 22, 7:00 p. m. October 30, 6:30 p. m. November 6, 6:00 p. m. The magnitudes are indicated on the map by stars of various kinds as follows: 0 magnitude, open center 1 magnitude, 8 points 2 magnitude, 6 points 3 magnitude, 5 points 4 magnitude, 4 points 5 magnitude, single dot All times expressed in Eastern Standard (not summer) time. 72 great Nova of 1918 appeared. It is now too faint to be picked out by the naked eye. Altair is moving toward us directly in the line of sight at a velocity of more than 1,200 miles a minute. This movement in the line of sight has been deter- mined by means of the spectroscope, which analyzes the light re- ceived from the star, and determines the velocity toward or away from us by the relative colors of light from cer- tain incandescent substances shining in the star and the colors of the same «substances raised to incandescence in the laboratory. The color of light depends upon the rapidity of the vibra- tions of the ether, bearing the light energy. If the vibrations are relatively many per second the lightis violet. If relatively few per second the light is red. If, then, light of a certain color is being sent out from the star and the star is rushing toward us at the same time, the number of vibrations we receive per second is increased by the movement and the light tends more toward the violet. If the star is moving away we get fewer vibrations per second and the light is shifted toward the red. The amount of shift is proportional to the speed of the star in the line of sight. Hence, measuring the shift enables us to determine the velocity and the direction to or away from us. To the southwest of Delphinus lies the bright star of the _ constellation Aquila. It may be easily recognized by its bright com- panion star above it a > aa no = : Al 3 ee r€ , *\ DELPHINUS, ' ; b. , or Loser ; * 4 6 ‘

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degrees to the west of the latter and rises

Senter, 1919 The Planets for September _ UR beautiful showing of planets in the evening sky is over at last. None are left. Mercury, the only one to set after the sun at any time dur- ing the month, is very near it at that time. It is in conjunction on the 26th, and it is only from then on that it sets after thesun. Till then it rises before it in the morning. On September 1 it may be seen rising before the sun, since it is then about eighteen

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about an hour before it. Mars may be seen as.a morning star, x y es and so may Jupiter; but Saturn and ; GH AB \ % Venus are still too close to the rising 1 y 2 sun to be seen for its glow. Mars and Jupiter are in conjunction with each 7S x A other on September 1, and the con- x f£N ak to. % | Pool? junction is to be very close. Venus | ond a ; and the sun are in conjunction on September 12, the’ conjunction being “inferior’’; that is, Venus passes be- tween us and the sun. It will be noted that Venus is retro- grading at this passage. The conjunc- tion is always “inferior”? when Venus reaches conjunction on retrograding. The planet will pass below the sun, and so we shall not be favored with what is known as a “transit of Venus.” That would be a very interesting phenomenon, but one that very sel- dom occurs where the planet passes directly in front of the sun’s disk. There will be a conjunction of the moon with Jupiter on September 19, and one of Mars and the moon on the 20th of September. The other conjunctions for the month will be invisible, since they will occur too near the sun. he

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| ; 7% ji \ J t 4 ' ‘Ss Lf T aoeee, | % ‘9 Ya H > ha ey 2 — e y fi se | s.2 7 || cert | \y. 9% 4 \ ee ‘ ‘ F / 4 aa Ay C we a ae e To use this planet map, cut out the disk below and use it as explained in ‘‘How to Use the Planet Map” How to Use the Planet Map HE planet map indicates a belt thirty degrees wide on each side of the celestial equator. To use it, cut out the circular disk to the right and mount it on a thin cardboard disk of the same size. Run a glass-headed push-pin through the center of the disk, pinning it to the center of the map. To see the section of sky visible at any time on any given date, turn the disk until the re- quired hour on the disk is opposite the required date on the chart line of the ‘‘mean sun.” To see when any celestial body rises or sets or reaches the meridian on any date, turn the disk so that the position of the body for that date on the map is in the required position with respect to the horizons. Read off the hour opposite the position of the mean sun for that date. The planets are designated by the following signs: gests neneeneHUUEEN PT Gy at E : MERCURY © SATURN b | VENUS Q URANUS © MARS o” NEPTUNE y | JUPITER ¥ SUN OAND MOON € | | i /

The POPULAR SCIENCE MONTHLY is publishing every month an ar- ticle like this by Mr. Hodgson. If you feel that these articles can be made more helpful, write to the editor. And if there are any questions that you would like to ask about stars, send them along Pin emt

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HE more imaginative modern astron- omers are inclined to believe, with the late Professor Percival Lowell, that Mars is inhabited. Assume that Mars is inhabited. How can we talk to the Mar- tians? What a world-wide sensation there would be if we were to receive from Mars a flash in response to a signal of ours! But how will the scientists signal to Mars? At its nearest, the planet will be about thirty-five million miles away in 1924. Various proposals have been made by Professor Pickering, Professor Wood, and the imaginative Professor Flammarion. In order to visualize and explain how these distinguished astronomers will communi- cate with Mars, Mr. Max Fleischer has di- rected the preparation of a motion-picture film for the Bray Studios. Through the courtesy of Mr. Fleischer and the Bray Studios we are enabled to preSent on these two pages excerpts from the film The distinguishing features of Mars are its “‘canals,’’ first dis- covered by Schiaparelli and later minutely studied by Lowell. It was Lowell who advanced the theory that the canals are great irrigation ditches. Mars has al- most dried up. Water is to be found only at the poles. If vege- tation is to flourish, the water of the melting polar snows must be conducted to the arid regions. Hence the canals. Several hun- dred were charted by Lowell. The canals are the only evidences of intelligent life that we have To the right we have the earth flashing a message to Mars. Who knows but some day we may tell the Martians all about our great war, all about the struggle for democratic ideals, all. about the terrible upheaval through which we have just passed! Perhaps we will learn from an older and wiser planet how we ought to run the Earth The well known French astronomer, Professor Camille Flammarion, to popularize the notion of Mars’ habitability, suggested that an electric lights. It would be a costly experiment. A huge tract of Sahara, for instance—would have to be “planted” with the lamps would have to be generated in a ‘power house big once said that he hated to die rich. Here is a chance to

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” Will the Martians Answer Us? =——— Professor Pickering, of the Harvard College Observa- tory, suggestéd. that a huge mirror be- mounted, to swing on an axis so that it can reflect the sun’s rays to Mars from any angle. It would take . m\| an enormous power plant who has done more than any other man in Europe ; }| to flash dots and dashes to enormous area on the Earth should be covered with a jj the wondering Martians. of land—a considerable portion of the Desert And what would they see? millions of lamps. The current to illuminate }/ As the picture on the left enough to run a railway. Andrew Carnegie shows, a luminous spot get rid of several million dollars at one swoop which alternately glows and extinguishes itself The picture at the left looks like a neatly cut-up farm. It represents Professor R. W. Wood’s proposed method of communicating with Mars. The Professor would cover some huge white space on the earth, a portion of the Desert of Sahara, for instance, with strips of black cloth. These strips he would wind and un- wind by means of electric motors. The result would be a series of winks. When the black strips are wound up, the white sand below re- flects the sun’s rays; when the strips are unrolled, the white areais covered. This is proba- bly the cheapest method of optical signaling yet proposed

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Popular Science Monthly Swapping Airplanes ~. in Mid-Ar Cast your eye to the right and see what happened when Robert Ken- = nedy, a former army pilot, tried to ; change in mid-air from Lieutenant & C. Vernon Pickup’s airplane to Lieu- . tenant David G. Thompson’s. Ken- nedy was the only one who was hurt. Are miracles never going to cease? The man dangling from the rope is Robert Kennedy. What’s he doing that for? Merely foolishly trying to change from the air- plane above to the airplane below. And now look at the other two pictures to see what happened to this adventurer SJ Thompson had maneuvered his plane (the lower one) to a point above the upper plane, so that Kennedy could make his jump. Thompson’s plane was caught in the under frame of Pickup’s plane (upper machine). Only a miracle saved them from death And here the two interlocked planes are shown plunging down to what seems to be certain destruction. Yet only one man was hurt, and he will live to repeat the experiment if he hasn’t cooled off since It’s Fireproof, as NY storage company can claim that its building is fireproof and that the rooms are separated by concrete floors and walls; but it took an enterprising Chicago company to make the fact visible to anybody who happens to look in the right direction. The concrete partitions, instead of ending, as usual, at the walls, have been extended right through them to the outside of the building. It is said that this method of construction offers no engi- neering difficulties, and of course it is easy to see that in a public warehouse of this kind it would have an extraordinary advertis- ing value. You Can See ' A storage. warehouse in Chicago takes pains to let everybody know that it is really’ fire- proof. Its concrete partitions are extended outside the walls, to be seen by every passer-by 76 The Beetles Stayed ECENTLY a earload of beetle-infested potatoes ar- rived in Los Angeles. The start- ling thing about this was that the car came from Idaho, where the potato-beetle is extinct. An investigation was made by Frederick Maskew, state quar- antine officer of California, and it was found that the same car had been used a little earlier to carry 2 load of potatoes out of Colorado, where the beetle flour- ishes. Obviously, after these po- tatoes were removed, the beetles lurked in out-of-the-way corners, waiting for a fresh load. The Department of Agriculture is taking steps to have freight- cars cleaned at the point of unloading in the future. ~~ ot tr et ot" et | ee | awk ‘sce in See | a Coe eee ae

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7 Vy. eT wa eS F , 1919 All Aboard the Air-Liner Think of battling storms a mile up! Think of cooking with the exhaust of engines! Think of landing in America with a_ parachute! By Waldemar Kaempffert and Carl Dienstbach by H. G. Wells, “The War in pipelike vertical passage, in which an the Air,” in which he describes aluminum ladder is placed. You are minutely an airship trip from Fran- in the huge envelope now. Better konia to New York? It will strike light your hand flash-lamp. It’s those who read it in 1908 as one of the dark, as you see. This foot walk truest prophecies ever penned—only, along the keel on which you stand is the trip took place at the end instead six hundred feet long, of the beginning of the “great war.” illuminated by only At Mineola the R-34 looked for two electric lamps. It all the world like a big (yet not over- is very, very narrow— large) sea-vessel ina harbor. The only fifteen inches paraphernalia scattered about lent wide. It would be color to the view—apparatus analo- hard for two men to gous to buoys, boats, coal lighters, pass each other. etc. There were lengths of heavy In this dark, narrow hose for water ballast, lighter hose passageway the men for injecting hydrogen into the de- sleep—sleep in ten pleted gas-chambers, huge mounds light Italian hemp of steel hydrogen bottles, auto-trucks with fuel, and wheeled. ladders for inspecting the hull and rudders, not to forget a ring of search-lights with their heavy electric cables trailing over the ground. In the Wheel-House Step into the forward gondola of the R-34. How like the wheel- house of a ship it is! See, here are the usual speaking-tubes, electric bells, and signals. What are these wheels on the side? They control the elevators when the ship is to climb or to glide down. This little cubby-hole is the navigator’s office. As you see, it has a table on which the charts can be spread. Over the chart table Scott and Cooke spent much of their time with protractors, dividers, and many navigational text- books, measuring angles of drift 4 and calculating course made good. | Aerial navigation is more com- \ plicated than navigation on the { surface of the sea. Note that in a separate sound-proof compart- \ ment back of the forward engine- 4 room is the radio station. \ ‘ ‘ Di you remember that old story the way up into the envelope—this WR nanan 4 % % Z Where does the crew sleep? In the big envelope above. Would you like to see for yourself? Here, slip % & ss s ‘S s ral > on these felt shoes. Why? Well, you will have to climb a ladder, and the ‘ nails in your leather shoes might X strike a spark. Remember that Nis this great craft is supported in the Pe. : air by thousands of cubic feet of View Com- NS e . pany LZ st . ' nflammable hydrogen. A Major Pritchard, on board the R-34, és _ didn’t wait for the ship to land. He Step this way, please. See, this is jumped overboard with a parachute ied ‘é Major G. H. Scott is thirty-six years old. Five years ago he was flying airplanes at Hen- don, England. He personally super- intended the con- struction of the R-34 at Inchinnan © Press Illustrating Service hammocks suspended from the frame- work. Each man shares a hammock with another. One man sleeps while his mate is on dutye Only a man with strong nerves can sleep in this fashion a mile in the air. One of the passengers, General Mait- land, writes in his diary: Getting into one’s hammock is rather an acrobatic feat, especially if it is slung high, but this becomes easy with practice. Pre- venting oneself from falling out is a thing one must be careful about in a service air- ship like the R-34. There is only a thin the keel on each side of the walking way, and the luckless individual who tips out of his hammock will, in all proba- \ bility, break right through this and \ soon find himself in the Atlantic. \ Running along the 600-foot \ cat’s-walk, inside the envelope, | are the parachutes and pneu- \ matic life-belts, kept in canvas i } \, outer cover of fabric on the under side of containers. Both parachutes ® and life-belts are always avail- able. If the men should be forced to leave the ship while it is over land,the parachutes will save them. Over the sea, parachutes and life-belts would be used. Every man dons a life-belt almost as soon as he steps on board. ag | j j Where the Gas and Fuel 4 | Are Stored Up above you are eighteen of them have automatic valves, which open when the pressure within them becomes too great. The other nine are equipped with hand valves. When the great craft rises, the hydro- gen expands. To prevent the compart- ments from bursting—they are made of gold-beater’s skin—the valves must be opened. But why both automatic valves and hand valves? Merely a precaution. Should the valves refuse j i / / hydrogen-gas compartments. Nine / tA Z ee

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If the R-34 could stand on end beside the Woolworth Building, she would be topped by the building’s flagstaff one hundred feet. But England has announced her intention of building an airship eleven hundred feet long 78 In 1492.Columbus sailed across the Atlantic in seventy days. The flagship wasithe Santa Maria, a decked ship of one hundred tons, with a crew of fifty- two men, commanded by Columbus in person The R-34, first airship to cross the Atlantic, is 640 feet long. From the top of her lowest car to the top of her gas-bag is about 92 feet. Her five engines develop a total horsepower of one thousand. The useful load is distrib- uted as follows: Fuel—4,900 gallons (weight The British ensign flew proudly at a regular halyard from the stern, as the picture below shows

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4 { | i ic, est et. jer ib- ht > ——S.eEeE HYDROGEN GA SP TANKS \LY CLOTHES BAGS GASOLINE TANKS to Cross the Atlantic Ocean 631 FEET ASOLMNE The first steamship to cross the Atlantic, which was one hundred years ago last spring, was the Savannah. She was 130 feet long; her horsepower was only 90; her speed but 6 knots. It took her thirty-seven days to cross 35,300 pounds or 15.8 tons); oil—2,070 pounds (.9 tons); water—3 tons; crew and baggage— 4 tons; spares—550 pounds; drinking water— 800 pounds. The total is 24.32 tons. The R-34 had thirty-one souls aboard. The crew included two wireless operators, who had sev- © Press Illustrating Service eral sets of instruments at their disposal. The broken away section of the picture shows how comfortable .the passage must have been. Good hammocks, hot food cooked on simple devices attached to the exhaust pipes of the engines—what more could be reasonably ex- The NC-4 has a wing span of 126 feet, almost as great as the Savannah's length. It took her about twenty- five hours to cross the Atlantic Ocean pected? The R-34 isa Zeppelin with a ven- geance. The arrangement.of cars,. propellers, rudders, etc., is exactly like those of the large German Zeppelin L-49, which was captured in France intact and which was fully described in the Popular Science Monthly. last year © Press Illustrating Service To reach:the envelope from the forward car, you climb up an aluminum ladder through a pipelike passage. Felt shoes must be worn, lest you strike sparks from the rungs. ‘fhe huge envelope contains eighteen compartments of explo- sive hydrogen. The vessel is as safe as a powder factory The two cars in the middle, of which this is one, were not in danger of bumping while the ship was tethered near the ground, because they are higher than the cars at the end. These cars are all engine. Cylinders, flywheels, valve-gearing, and all else crowd the interior

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to work, a fire might start and the crew might have to leap for life. Even flying over a warm city causes expan- sion. Over the cold sea the gas con- tracts. Thus, while flying over the ice-floes around Newfoundland, on the voyage to Ameri- . ca, there: was a con- - traction of forty per cent. Hence the final inflation takes place at the minimum tem- perature—in other words, after sunset. The fuel (5,000 gal- lons) is contained in eighty-one tanks in the envelope.* Each tank has a capacity of seventy gallons. Sixteen of these tanks are fixed to the frame- work. The others are called ‘“‘slip tanks,” and may be filled with water as ballast. As a rule the water ballast is carried in canvas containers. The addition of al- cohol prevents it from ° freezing at high alti- tudes. In addition there are eight emergency containers, four forward and four aft. They carry, all told, about three thousand pounds of water, which is pumped in as the atmos- pheric conditions may de- mand. The drinking-water is drawn from three tanks. Besides these there is a reserve tank containing dis- tilled water, which may be used in case there is a short- age of drinking water. On the way from England the men were limited to a pint of water at the end of each day. Where do the men eat? Here in the dining-room, right in the center of the envelope, the only place where the cat’s-walk is wide. But where are the tables? They are fastened on hinges to the framework. All the old naval class distinctions are swept aside; for the officers and men use the same dining-room—if room it can be called. Hot Food for Dinner The dining saloon is large enough to permit half of the crew at a time to eat. The food is cooked or heated, as it is wanted, on stoves attached to the exhaust pipes of the engines. Hence the engine-room serves as a kitchen. Chairs? There are none. The diners stand at a cupboard. The meals are good. One day there was an excellent stew—the meat cooked just right, with potatoes and carrots, © Press Illustrat- ing Service A cat was smuggled on board, for luck. Nearly every member of the crew had a mascot, from the engineer officer,who wore one of his wife’s silk stockings around his neck, to Major Scott with his gold charm ‘Thumbs up” served on.an aluminum plate with knives and forks, and, last but not least, one cup of fresh water. Lieutenant Shotter says in his diary: The mess cooks are now preparing the midday meal—cold roast beef, cold pota- toes, bread, cheese, and chocolate. We were to have had beefsteak, but the two wing engines which are fitted with cookers are stopped for general adjust- ments, so we are tak- ing cold lunch instead. Later he writes: Just had tea at four o’clock with General Maitland, Majors Seott and Cooke, and Lieutenant Harris. The men in the gondolasare notcold. The cars are heated by the radiators of the motors. The two side cars, just large enough for two men to do their work in, contain each one engine. Hence the engines are distributed as fol- lows: one in the forward car, two in each of the central side cars, and two At night searchlights in the neighborhood of New York swept the sky, to guide the R-34 as well as to find out whether she had arrived after sunset in the stern car. There are, however, only four propellers, the two engines at the stern having only one propeller. Two men work at the engines, one man operating and the other oiling. General Maitland entered one day in his diary: Slight trouble with starboard amidship engine—cracked cylinder water-jacket. Shotter, always equal to-the occasion, made a quick and safe repair with a piece of copper sheeting, and the entire supply of the ship’s chewing gum which had to be chewed by himself and the two engineers before being applied. It was difficult for the crew to realize that they were.on a trans- atlantic voyage. The trip was actually tiresome. Lieutenant Shotter, who is responsible for . 80 Popular Science Monthly | the performance of the engines, noteg in his diary: I am certain that passengers wi fearfully bored unless atte = organized. One can see at the best onl a vast expanse of sea, and at the wouk fog, or an awfully downcast sky. which the Atlantic alone can bring. Our gramophone has been a God-send to us during meal. — oe e men had exercise enough. the 600-foot ‘“‘cat’s-walk’” hey woe run from end to end, a mile in the air There are also steps in a vertical ladder to the top of the ship for those who are ener- getic or have duty up there. How It Feels to Travel through Clouds They saw little of the ocean through. mist and clouds, having often a sea of clouds below and asky of clouds above. What is it like to a true denizen of the air? Only the ocean traveler knows the cumulative effect of waking up, eating, going to sleep, and waking again day after day on the water, What must it feel like to become similarly a part of the atmosphere, to drive on and on with only clouds, stars, moon, sun, the blue sky, mists, and an occasional glimpse of the dis- tant ocean below? Officers and crew have sketched in words the charm and peril of their journey—sunset tints like paintings, magic mirages in the fog, phenomena that have never before been so thrillingly witnessed. Groping in the Fog The R-34 voyaged to these shores in a period of comparatively favora- ble weather; yet there were fogs over the north Atlan- tic, originating from ice- bergs or from chilly water flowing south from the Bering Straits. As the re- sult of a series of curious meteorological circum- stances, the R-34 had to stem temporarily strong contrary winds and several thunder storms. Her navigator complained of trying up and down currents, ‘‘bumps,” near the end of the voyage. No wonder they should occur at the very edge of a memorable heat-wave. Such is the power of the engines ‘that these diffi- culties were easily overcome. ©) Press Itustvating Service Hundreds of steel bottles containing com- pressed hydrogen gas were shipped to Mine- ola in order to inflate the gas-bags of the R-34

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al- ng ild ‘ir. er- in ‘ir Ss, g, er ly September, 1919 The lack of meteorologic knowledge was disconcerting. Lieutenant Har- ris, the weather observer of the R-34, remarked: We learned that our old boat was as fickle as 2 bug, and insisted upon going over the high-pressure areas and plunging and diving through atmospheric changes. It took a good sailor to come over, and it will take sea-legs to get back. The task of navigating an airship is hard, because the air-currents are invariably in- visible to the eye and must be sensed by delicate instru- ments and calculations. They saw the Atlantic only a few times after they left the Irish coast. It was necessary for Cooke, the navigator, to use the clouds as a hori- zon to make his obser- vations. The cloud horizon is not clearly defined; the observer must guess a little as to the true line. Hence an error of fifty miles may occur because the observer has not guessed very well. Shotter Sees His Double By means of the shadow cast on the water, and also by special instruments, the navigator was able to measure the drift angle. Sometimes, when the R-34 plunged through the clouds, it was dark, cold, and wet. The windows had to be shut. Periodi- cally the fog cleared away, so that the men on board could see the sea for a minute or two. Eyes smarted because of the bright light reflected from the fog. The fog played some curious tricks. Read this from Lieutenant Shotter’s diary: Just had a shock. Opened the engine- room window. It is a large affair. Two men can lean out. I looked out and saw another engine-room opposite and a man’s figure looking out. Ye gods! My heart beat frantically. Only the reflection from a bank of very thick white fog. We get extraordinary sights up here in this beastly fog—uncanny sights, I think. © Press Illustrating Service The field at Mineola was cluttered with pipes, joints, and paraphernalia of all kinds to refuel the R-34 and replenish her gas compartments on her course. To escape the clouds above and be- low, Major Scott had to climb at times to an altitude of four thousand feet from two thousand feet. After the airship had passed into Fundy Bay, Scott turned east off his course to dodge a storm, putting on all en- gines. In this he was very success- ‘ful. The R-34 passed through the outer edge of it. It is no easy task to keep the mammoth dirigible We had a very bad time indeed [says General Maitland] and it is quite the worst experience from a weather point of view that any of us have ever experienced in the air. During the storm some wonderful specimens of cumulo mamatus were seen and photographed. General Maitland wrote constantly of fogs in his diary: Suddenly we catch a glimpse of the sea through a hole in the clouds, and it is now easy to see we havea slight drift to the south, which is what was estimated by both Scott, the cap- tain, and Cooke, the navigating officer. A few minutes later we find ourselves above the clouds, our height still being fifteen hundred feet, and beneath the cloudy sky are clouds at about eight thousand feet. We are, therefore, in between two layers of clouds, a condition which Alcock and Brown found themselves on more than one occa- sion on their recent flight from west to east. There were remarkable rain- bow effects on the clouds. One 81 Lieutenant-Commander Lans- downe, the American observer on board, did a two- hour trick at the wheel, and found it hard work complete rainbow encircled the airship itself, and the other—a smaller one— encircled the shadow, both very vivid in their coloring. General Maitland writes: To the west the clouds have lifted, and we see an extraordinarily interesting sky— black angry clouds giving place to clouds a gray mouse color, then a bright salmon- pink clear sky, changing lower down the horizon to darker clouds, with a rich golden lining as the sun sinks below the surface. The sea is not visible. Still Larger Airships Are Coming As the trip’s slowness resulted partly from gen- eral eastward trend of - North .Atlantic weather, it follows that to cross from Europe to America an airship ought to navi- gate: in the trade-wind regions or that an airship much larger and more powerful than the R-34 be employed. A _ dirigi- ble’s speed and reliability grow with size—a view which has often been ex- pressed by Carl Dienstbach and which is now rein- forced by General Maitland’s announcement of an airship, nowin course of construction, double the size of the R-34. The commander of the R-34 kept in constant communication with our Weather Bureau during his brief stay. At the slightest indication of danger he would have slipped his mooring and floated away. As it was, the R-34 left at the urgent suggestion of the Weather Bureau. A storm was coming east from the Great Lakes, and the R-34 was in positive danger. The voyage of the R-34 has strik- ingly demonstrated that Zeppelins must be navigated like sailing vessels, strictly in accordance with the winds, permanent or temporary. Even much faster Zeppelins—the British plan a hundred-mile-an-hour rigid dirigible —will pay commercially only if they follow the easiest route. They should cross from Europe on the Columbus course, aided by the trade-winds. The Antilles and possibly the Cape Verde Islands will serve as useful fuel stations. We in America needed this demon- stration of a Zeppelin’s capabilities. We have been too skeptical, although our vast country is better suited for atmospheric cruises in giant airships than any European country west of Russia. That long period of gentle, quiet weather from June to October is ideal for air navigation.

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The same new design used in this hundred-ton oil-carrier, recently built in England, may also be applied to craft having a capacity of twenty thousand tons Oil-Carrier and Storage-Tank in One RITISH shipbuilders recently evolved a type of craft for carrying oil in bulk which presents several new features. This craft, which in general outline resembles one of the American whalebacks, is primarily intended for transporting oil in the overseas trade, delivering it to a shore line or to some craft afloat. The design also makes it possible, however, to use the craft as a stationary storage-tank for oil. The craft shown in the picture above has a capacity of only one hundred tons of oil, but its underlying principles may be applied to much larger craft. Several having a capacity of twenty thousand tons of oil each have been designed. The craft has a length of eighty-nine feet, a width of nine feet, and when loaded draws seven feet eight inches in salt water. The oil is carried in four hold compart- ments and two tanks between decks, which are placed at the fore and aft ends of the craft. Each of the hold compartments is fitted with a sea valve operated from the space between decks. When the oil is removed from the compartments by the electric- ally driven pump, sea water flowsin at Why let baby the bottom through keep you from thesea valves. When 2 bicycle trip? oil is pumped into the compartments, it displaces the sea water, which is forced out through the valves. This arrangement makes it possible to main- tain approximately the same water- line, regardless of the quantity of oil in the: hold. Electrical level- indicators installed in the different com- partments, and a specially designed electrical steering arrangement which may be operated rear wheel be used on any receptacle, is easily detached for cleaning A Rumble-Seat for the Bicycle 2 HEY’RE off on a bicycle trip, father and child, the child fitting in a rr oe “shell’’ attached to father’s rear wheel. This is the English version of the Indian papoose idea, father doing the lugging. When the picture to the left was taken the family had just started on their Popular Science M onthly Is Your Shaving-Mug Sanitary? _ may keep your shaving soap in a mug or in some other receptacle, but you must keep it somewhere. For the sake of con- venience the container should be easily accessible and, for sanitary reasons, easily cleanable. All of these conditions are fulfilled in a convertible soap-holder invented by Ernest Hunold, of Providence, R. I. The container is so simple of con- struction that the inventor, accord- ing to his own statement, had no difficulty in inventing and perfect- ing it in about two hours and a half, Undoubtedly, the greatest ad- vantage offered by this soap-holder is that it may be used with any mug, cup, glass, or can, and may quickly be detached for a thorough cleaning and sterilizing. The metal holder con- sists of a semicircular flat base with an ex- tension in the form of a hook-shaped clip which fits over the edge of the re- ceptacle. At the opposite side the base is turned up at right angles, forming the support for two slidable arms. ADJUSTABLE SUPPORT trip; the baby was enjoying the scen- ery from his ob- servation platform. And his father was not at all disturbed by his son’s un- balancing weight. The bicycle is kept from top- pling by asupport- ing bar, attached to the side of the “shell.’”’ The baris lowered when the ‘bicycle comes to rest; and when the bicycle is moving from the craft tow- ing the oil-carrier, complete the equip- ment. The father has left the bicycle long enough to make his child a cup of tea. : a bar on the side of baby’s “shell” is low- the side of the ered to keep the bicycle from toppling over shell. the bar swings up Meanwhile into its place on ———

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m=O OD § SS ew 6 8 7 Ge a Oe a a ee eee OU know just how it is: you y have pictured it in your imagina- tion a thousand times. You gather a few bits of bark, dry moss, or leaves, snap up a pile of dry twigs (if you are wise you have plenty of both), or, if the woods are wet, you split a seasoned stick and whittle out shavings from the dry heartwood. You pile the kind- ling loosely over the tinder, lay on a few heavier sticks, and light your match. So far, all is well. A flame leaps up as you touch off the dry stuff— then dies down into a smolder. You get down on your hands and knees and blow for all you are worth; and when you are out of breath, and your eyes are filled with smoke and ashes, you rise perspiring, about to give up in dis- gust. But while your back is turned a tiny flame has crept out from under- neath, reaching upwards, leaping from twig totwig,and, loand behold, youhave it—the crackling, flashing camp-fire! The Soul of the Camp The camp-fire is the soul of the camp: it furnishes warmth, hot food, light, and protection. Its glowing circle holds back the damp and dark- ness, and builds a temporary home for you in the midst of the wilderness. If your party is large, make it the duty of certain specified members to gather wood for the fire. This should be done in daylight. Clear a space in the open, away from tents and trees, and lay down a circle of stones, or dig up the earth and wet it down thoroughly. Provide, also, a number of logs or stones, at a comfortable distance from the fire, for seats. Pile up a rather large cribbing of light, dry wood with a quantity of tinder underneath; over this set the heavier sticks on end, forming a sort of loose wigwam or pyramid. As the fire burns down fresh wood can be added, and as the ends burn off the butts can be thrown on the fire. Appoint or elect a leader to light the fire and to call upon each in turn to contribute to the evening’s en- tertainment. Perhaps someone will bravely volunteer to toss a few flap- jacks, or corn or potatoes can be roasted in the hot ashes. When “Good Night, Ladies” has been sung, pour water over the embers and make sure the fire is entirely out, unless you are using an all-night fire. This is very important, for if the wind should rise in the night, and the woods are dry, you might start a forest fire. From the general run of camp pic- tures, one would think that cooking is the principal business of camping out— and it usually is for that member of the party who has experience in the preparation of camp dishes. With a few common-sense precautions a fire of ordinary proportions can be built as safely in the woods as in the open. The Cooking Fire The proper fire for cooking is a small one. You will have a good draft if you place it near the base of a large ee The author knows how to get the best draft and heat from a small fire tree—but don’t build it against the tree, or you will kill the tree. First, clear the ground of all brush for some distance in a circle around the fire. In very dry weather, dig up the leaf mold with an ax and pour in a few buckets of water. In winter, clear the ground of snow, or you will soon find yourself in a lake of slush. Your snow-shoes will make ex- cellent shovels if the snow is not , crusted. If it is, break it up with the ax and chop well into the frozen ground. Provide an abundance of kindling. After the small fire is well started and the ground warm beneath it, it will burn almost anything. The two things that a camp fire requires and must have are fuel and air. Don’t throw on the sticks any old way, so that the air cannot draw from under- neath and upward through the mass, and don’t stir the fire continually so that you break it up. If you want a large bed of coals quickly, lay on a 83 | Cooking in Camp How to build and care for wood fires and the precautions necessary to make them safe By Charles Coleman Stoddard considerable amount of wood and let it burn down altogether. Hardwood is necessary for this purpose. If wood is green or damp, a split edge will generally take fire more quickly, and it is well toset the sticks onend. This increases the draft, and the outer part of the wood will dry off while the inner side is burning. For a slow fire, and for the night fire, lay the sticks horizontally and all the same way. For the cooking fireplace, take two green logs about six inches in diameter and three or four feet long, leveling off their tops with an ax (or use large flat stones if you have them). Lay these parallel, slightly closer together at one end than the other, and far enough apart so that your cook-pots will set squarely upon them. Dig out a little trench between them, and at the narrow end build your fire. Over the blazing wood set the pots to boil, and as coals form rake them forward to the other end of the trench for frying and broiling. Never attempt to broil or fry over a blazing fire: set the pan directly upon the glowing coals. When cooking over a large fire, draw a pile of coals to one side and remove all the unburnt smoking wood. You can then cook in comfort, with- out roasting yourself and without danger of burning the food. Roasting and Baking If you are to attempt roasting meat, or baking with the reflecting baker, build the fireplace in front of and parallel to the face of a large boulder, or set up a fireback of logs to throw the heat of the fire forward. Hang your cooking-pots over the fire on a green stick as shown To roast meat or game, suspend it before the fire on a wire, which, in turn, is hung from a high branch with a piece of strong cord that will twist

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and consequently keep the meat con- stantly turning. Underneath set a drip-pan partly filled with hot water, and baste the meat frequently to prevent its burning and to provide gravy. Often you will want to suspend your cook-pots over the fire. Your own ingenuity will suggest many ways of doing this. The simplest form of crane is the “‘tea-stick”—a long green pole slanting above the fire, its butt thrust under a stone or log, and the tip from which the kettle is suspended held above the fire by another stone or crotched stick. For your permanent camp, set up strong crotched sticks, about four feet long, at either end of your trench Eat? Why, you are hungry enough to eat a wool blanket, and the woods did it fire, and across these lay a long “lug pole.”” On this you can use the wire pot-hangers, or cut several crotched sticks, leaving one leg from one to two feet long. At the inner side of this longer leg cut a deep notch for the bail of the kettle. By having sticks of varying length you can secure almost any degree of heat, or the pot may be hung to one side and kept hot indefinitely. At all times bear in mind the virtues of the small fire: easy to build, easy to control, and easy to put out. A little fire is all that is needed, and the work that it will do, with practice, is amazing. The Quick, Hot Fire When you come in from fishing or tramping you are in no humor to swing an ax and drag up logs. Break a few handfuls of dry sticks, none bigger than your thumb, and set them all blazing briskly at once. By the time the kettle has boiled, you have ample coals for frying or broiling. If your menu is more elaborate, pro- vide a few extra sticks. While you eat your meal set on another pot of water to heat, and as you finish with each dish wash it. When the meal is over and the pipe smoked, pour the dish water over the smoldering embers—and you are ready for the sandman’s coming. When going into a more or less permanent camp, even in fine weather, it is well to take the time to prepare a quantity of this small wood— enough for several meals—beforehand. Split the larger sticks through once or twice with the belt-ax, and, mixing about equal quantities of hard and soft wood, tie it up with string or strips of bark into bundles six inches or so in diameter. These can be thrown in along the sod-cloth with the other duffle. When meal-time comes, all you need to do is to open a bundle, throw a few sticks on the fire—fan the smoking coals, and you have a blaze. If it rains in the night and douses your fire, you can laugh defiance, for you have dry wood to cook breakfast over. Such a small fire can be built safely just under the outer edge of the tent, and you can live in comfort until the rain clouds have passed. By all means, if only for companion- ship, have a fire at night, but don’t burn wood simply because it is abundant. The night fire has another use besides warmth, though happily not necessary now in the greater part of this country. Where dangerous animals abound, it is the custom to build extra fires, sometimes a circle of them, about the camp, to ward them off. Either because of the light of the blaze or the odor of the smoke, very few wild animals will approach a fire, or even smoldering coals. Watch Your Fire There are numberless precepts of the camp fire. The first of these is care- fulness, and the rest mean exactly the same thing. The careless camper comes—and goes, leaving a trail of destruction behind him. Of 7,814 fires fought by foresters in the national forests in a single year, 5,682 were preventable and caused by human agency; 1,288 of these were caused by campers. The great Minnesota fire of October, 1918, caused by negligence in starting fires to clear land and failure to control them, completely destroyed 200,000 acres of timberland and burned over 400,000 acres more, causing a loss of approximately $25,000,000. Swept by a sixty-mile gale, it destroyed sixteen towns and villages, including Cloquet, .a city of 10,000 people, burned more than 5,000 homes, and cost 432 lives.* Every part of the woods is in- flammable, from the leaf mold under our feet to the top of the tallest tree. When you build a fire in your home, you build it in a proper container. You would not think of building it upon a barn floor or in the midst of a pile of litter; why then build it, without thought or preparation, where you risk the destruction of the forest canopy that has taken centuries to build? A fire in the woods must always be carefully built; it must be watched constantly at all times, and never left, even for a short time, without being extinguished. If it gets beyond: your control, you have no neighbors to summon, no fire department to come to your aid. *Ep1tor’s NotE—These figures are official and were secured from the National and State Foresters. 84 is likely .to spread Popular Science Monthly . Acquaint yourself with the laws of your State regarding forest fires before you go into the woods. If it is neces. sary to have a permit to build a fire secure it. Remember it’s not a matter of sentiment, a matter of whim or the selfish interest of a few sportsmen that requires you to take every pre. caution to extinguish your fire thor. oughly when you break camp. The State and nationai laws are very simple and explicit, and provide severe penalties, not alone for care. lessness with fires, but also for re. moving or defacing any fire notice, No warrant is needed for arrest. Never build a larger fire than neces- sary. Never build it against leaves, rotten wood, or other material that it, or against stumps, or large or hollow logs, where it is difficult to put out. In windy weather, build it in a depression or surround it with a wall of rocks, and clear the ground for a wide space all around. Every person who goes into the woods should realize the danger of fire, and recognize his personal re- sponsibility, not alone in guarding his own fire, but in laying aside. every other plan to assist in fighting an accidental fire. In justice it should be stated that it is not the sportsmen and experienced campers generally who are at fault. It is the thoughtless ‘‘man from town,” the picnicker, and the casual camper, who cause the greatest damage. A caution to the sportsman who smokes. Never, in the excitement of the moment, light your tobacco and toss the burning match into leaves or Build the fire in the shade. is hot enough work without the sun Cooking dead grass, and never drop the glowing heel of your pipe or a cigar stump without grinding it deeply into the earth. Try breaking every match between the first and second fingers with the thumb of the same hand before throwing it down. We are only human. A single encounter with a glowing match-head, and we have learned carefulness—the most important ‘lesson of the woods— forever.

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ndy 1 or and : all the r of re- his very an that iced ult. vn, ” per, who it of and S OF the igar ply ery ond ame iter we 10st S —_— A Winchester Junior Rifle Corps Unit at rifle practice under supervision of Unit Instructor. A rifle range that any boy can build HERE to shoot— is that the prob- lem that has kept you from joining the Winchester Junior Rifle Sharpshooter Corps and learning the oe joy of trigger magic? If so, a few practical hints are all you need to rig up a rifle range of your own, where shooting can be made safe. The most important thing is to select a backstop that will catch and hold the bullets. Every shot must be safe. The side of a hill (as in the picture) makes the best backstop for a range. Dig it out square and face it with light boards to hold your paper targets. If there’s no hill available, you can build a backstop in your yard. A large packing case filled with sand or earth will be safe, but any back- stop should be at least 4 feet high and 4 feet wide. If your cellar or basement will give you a clear range of 50 feet, it will make a fine place for shooting all the year ’round, and in all kinds of weather. Here you can make a plain backstop as suggested above. Start a W. J. R. C. Unit with your friends The job of finding a place to shoot, rigging up a range and getting your rifles is always easier and cheaper when you have a bunch of your chums in on it. There’s more fun, too, in the actual shooting when there are other fellows to compete with. So why not get together with half a dozen of your chums, join the Win- chester Junior Rifle Corps and or- ganize a regular Unit which will be officially recognized by National Headquarters? Any boy who starts a Unit receives a Special Service Pin. The W.J.R.C. will help you from start to finish in rigging up an indoor or outdoor range. The W.J.R.C. gives you all the in- struction necessary to become a real expert in the use of a rifle. It pro- vides for officers, supervisors and adult instructors to make your shoot- ing safe. It costs you nothing to join the W.J.R.C.. There are no dues and no military obligations. The W.J.R.C. was organized solely to encourage bet- ter marksmanship and better sports- manship among boys and girls of America. It is intended to develop the qualities of fair play and manli- ness which are essential to success in after life. Any boy or girl not over 18, who is in good standing in his or her community, is eligible. Membership in the W.J.R.C. covers the entire United States. There is hardly a town now that has not at least a small Unit of the big National Organization where boys are competing for the famous Win- chester Marksman, Sharpshooter and Expert Rifleman Medals. You, too, can earn these trophies of marksman- ship if you join the W.J.R.C. and start shooting now. Get the official plan and rule book Write today for the Winchester Junior Rifle Corps “Plan for organiz- ing a W.J.R.C. Unit,” and for the official rule book “How to handle a rifle safely.” This booklet tells you all about the W.J.R.C. and describes in detail the fine points of shooting— alignment of sights, the three correct positions, rules for gun safety, the care of rifles, and the proper rifle for you to use. If you are a boy scout or a member of any other boys’ organization, state what organi- zation and give the name of the official in charge. National Headquarters Winchester Junior Rifle Corps 275 Winchester Ave., New Haven, Conn., U.S.A. Division 920 Standard types of .22 caliber Winchester Rifles, popular with members of the Winchester Junior Rifle Corps WINCHESTER MODEL 90. Take-down repeating .22 caliber rifle, 24-inch octagon barrel. The standard target rifle for over 25 years. WINCHESTER Toke-down .22 caliber single shot rifle. A low priced, light weight gun made in two sizes.. WINCHESTER JUNIOR RIFLE CORPS National Headquarters, 275 Winchester Avenue, New Haven, Conn., U. S. A. 85 Winchester Junior Rifle Corps National Headquarters, 275 Winchester Ave., New Haven, Conn., U.S.A. Division 920 Gentlemen : Please register my_name as a member of the Winchester Junior Rifle Corps, and send me a membership button and certificate of membership. Also tell_me how to organize a local Unit of the W. J. R. C. Very truly yours, GG nditdicectucuvinen eau ea ene 2, i a ee

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Popular Science Monthly Talk Loudly Without Raising Your Voice You can make some very interesting experi- ments with easily made electrical apparatus the most interesting forms of ex- perimental electricity. The ap- paratus can be used to talk through show windows (loud talker outside in street and salesman talking into microphone transmitter) ; as a detecto- phone; for transmitting phonograph music from one room to another; as a radio ampli- fier; as a tele- phone exten- Fig. 4 sion (by plac- A thin carbon dia- ing the regu- phragm is usedinthe lar telephone interior mechanism receiver against that of the telephone transmitter) and many other uses which will suggest themselves to the experimenter. The transmitter is highly sensitive. The shell of a watch-case telephone receiver makes an excellent outer case as indicated at P in Fig. 3. For the interior mechanism we need a thin carbon dia- phragm A (Figs. 1, 2 and 3) preferably standard size —2¥% in. wide and 1/64 in. thick. A felt washer E 1144 in. in diameter with walls fig 2 3/16 in. square should be made. This washer should be made with a tongue X 3/16 in. long. Glue the washer to the center of the carbon diaphragm. Another carbon button 114 in. wide and about \ in. or 3/16 in. thick is made. The thinner it is the more sensitive the apparatus will be. A hole large enough for a Y4-in. screw is bored through the center of the carbon button. Counter- sink the hole a little on one side so that when a 14-in. bolt, 1% in. long, and nut are bolted on this button, OUD talking apparatus is one of 5 holes in cap.. WS. sco Transmitter Cap ee y é Copper Strip” P. Fig. 3 Fig.4 The transmitter in detail. Here lies the secret of the loud talker By Henry Stedfield the head of the bolt will not touch the carbon diaphragm, Fig. 2. The car. bon button can be easily made with a hack saw and the hole bored with an iron bit. Insulate Bolt with Shellac It is better to insulate the head of the bolt S by dipping it in shellac. The carbon button must now be glued to the felt washer the terminal C of the carbon button. The three small wires have more flexibility than one large wire. The carbon diaphragm should now be put in place, and a receiver cap screwed on the transmitter as shown in Fig. 3, The transmitter will be more sensitive if a number of 14-in. holes are bored in the cap as shown in Fig. 4. Any watch-case receiver used. The double-pole type is more efficient, but it is with the head of the bolt and the beveled side of the easier to make the receiver from a carbon inside, see single-pole type. First remove the Fig. 2. After the glue is dry, the chamber between the two carbons should be loosely filled with polish- ed carbon grains or balls. They must never be packed tightly, but should fill the space entirely. Do not touch the carbon grains with the hands; as the natural oil from the hands destroys their sensitiveness. It It is much better for the experimenter to buy these carbon grains from an electrical supply house than to attempt to make them. A piece of paper bent to a sharp scoop will simplify the filling of the chamber. The openings between the ends of the washer must be plugged with a piece of felt D, Figs. 1 and 2. This can be done with a pin or sharp pointed knife. Making Connections The binding-posts, N and O, Fig. 3, are fastened on the bottom of the trans- mitter. The connection from one of the binding-posts to the carbon dia- phragm should be made with very thin copper or brass strips, %@ in. wide and about 11% in. long, as shown at K, Fig. 3. The copper strip is bent over the edge of the shell and cut off flush at the edge of the rim L, Figs. 3 and 4. Do not place the carbon dia- phragm with its parts over the strip, as the strip, being higher than the rim of the shell, would crack the diaphragm when the cap is screwed down. For that reason, by means of a small file or knife, make a cut in the rim of the shell at L. This slot must be exactly the thickness of the copper strip, so that when the strip is put in the slot, the top lies flush with the rim of the receiver shell. The other “terminal N should be connected by three No. 28 insulated copper wires to 86 Another coil of heavy wire, Y, must be wound over the core Z permanent mag- nets from the re- ceiver, then take out the spools of wire and its soft iron core. Another coil of heavy wire Y must be wound over the core Z in Fig. 5 in place of the fine wire. One hundred and fifty feet of No. 24 enameled or cotton insulated wire is about right, as this will give 5 ohms resistance. Give this coil a coat of shellac to hold the wires in place; then bolt the electro- magnet back in its original position. The connections should be made from the magnet to binding-posts on the back of the receiver. Completed Instruments The instruments are now complete, and should be connected as in Fig. 6 using at least four dry batteries. Transmitter, Receiver ZR When the _in- i ‘am struments are y completed they should be con- nected as shown Talk in a moderate tone into the transmitter and the receiver will talk very loudly and distinctly, the voice being heard clearly a long way off. It is important that all connections be made as tightly as possible. The apparatus can be used as a marvelously sensitive detectophone. Put the trans- ‘mitter back of a picture, and run the wire to an adjoining room, and you can become a detective. can be

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on. re he ut ed | 3. | ve | ed be re he 0e, he ig- re- ke oft ler ire e, S. September, 1919 Smokeless and Black Powders Money-Back Shot-Shells Get a box of The Black Shells from your dealer. Shoot them—in the field or at the traps.. If you don’t like them, get your money back. Just take the unused part of the box back to your dealer. We authorize him to refund to you at our expense the price of the whole box with absolutely no question or quibble. The Black Shells have reached such a state of perfection—in water- proofing, in speed, in power and in uniformity—that we can guarantee them without limit. You can get your pet load, in smokeless or black powders, for every’ kind +s BLACK SHELLS Smokeless and Black Powders of shooting in the Black Shells. Go to your dealer for a free copy of the U.S. Game Law Book. If he doesn’t carry The Black Shells, send us his name and address with your own, and we'll send you the book by mail. UNITED STATES CARTRIDGE COMPANY, 111 Broadway, New York _ General Selling Agent : National Iead Company, Boston, Buffalo, Cleveland, Chicago, St. Louis, Cin- cinnati ; United Lead Company, New York, Philadelphia: National Lead and Oil Company. Pittsburgh; James Robertson Lead Co., Baltimore; American Smelters Security Co., San Francisco; Hingston-Smith Arms Winnipeg; John Hallam, Ltd Toronto. ee ies 87 Exactly the same guarantee that goes with the Black Shells applies also to (Gs) CARTRIDGES Have you tried our 22 N. R.A. Long Rifle Lesmok Cartridges? They areas accurateat 250 yards as the larger calibers are at 1,000. Made with solid lead and hollow point bullets. Cost no more than other cartridges of same size and style. Send for circular C93.

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Popular Science Monthly How to Prevent Polarization in Sal Ammoniac Cells VERY simple but equally effective method of preventing the output of sal ammoniac cells from rapidly diminishing is as follows: Dip the carbon rod of the cell in dilute nitric CARBON ts fw DILUTE — — When wet batteries run down quickly there’s a reason for it The Trade-Mark | acid and heat for a few moments in a gas flame. The occasional repetition that Reflects the Truth of this treatment will increase to a remarkable degree the output of This picture tells the story of current from the cell. : Txer Iohnson safety. The rapid falling off of- current in r Joht yer é such cells is due to the formation of The Iver Johnson is known the a non-conducting sheath of hydrogen EE a ee h gas about the carbon rod. The above a evaver: t a treatment will dispose of the hydrogen can't go off by accident. Drop it, and prevent the polarization.—FLoyp throw it. or ‘‘Hammer the Ham- L. DaRRow. ner’’—it won't go off. Just one way to discharge an Iver Johnson —pull the trigger a// the way back. To Repair that Broken- Down Bicycle N INVERTED bicycle is an un- steady thing at the best, and : IVE re ; ft = RR Ss } N when in this position for repairs can behave in a most exasperating man- SAFETY— me EV ner. Here is a stand that will tame Nthisl yy Nile es LVE RS it down and make it much more tractable. The bicycle is held upside down so ty of the Iver Johnson is auto- that the wheels and other parts most Cate aS ood ole hace) etwas elolaobtelcamae) do to make it safe. That's Pb aoms oleh am aboctieGr-loleletam of-hiatel-ar-te\ So am fo) obetsvepoube ana oleae olojecten Iver Johnson is alive, alert, ready. 1 tempered piano-wire springs assure for use. And the per- fect rifted barrel speeds the bullet straight as a streak of light just where you aim Choice of three grips: Regular, Perfect Rubber, Western Walnut. Three Booklets Free h reading. ‘‘A’'—Firearms: “B” A repair stand that clamps the bi- . “4 i cycle steady while it is being fixed Motorcycles. Yours free asking. | 7" liable to need overhauling are free and far enough from the floor to avoid the necessity of stooping over to work upon them. The saddle cannot be rontt2t marred as it rests upon gunny sacking, ¢ Superior and the spring steel bar with tongs iVER JOHNSON’S ARMS & CYCLE WORKS & 7 cin, holds the handlebars firmly but may 343 River Street, Fitchburg, Mass. Sa be instantly released by a slight pres- —, sure of the foot. Bicycles vary as to length of wheel- base and distance between saddle and handlebars. This is allowed for by making the gunny sack covering about lealer cannot supply the Iver Ja 016 Gn 0 IH 0 b MB oF beelommr- bole Mme buaccy ii] supply you through him. New York 717 Market St., San Francisco

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ly eB

September, 1919 f The Standard Spark Plug

of the World ZEW They Have Always Met the Emergency If you could get a composite expression on spark plug merit from the Society of Auto- motive Engineers it would be the highest tribute that could possibly be paid to AC. For these automotive engineers know spark plugs. They know that throughout the his- tory of the motor car industry there has always been an AC Spark Plug ready to meet each new engineering rroblem. That is why the majority of manufacturers of high-grade motor cars have been using AC Spark Plugs for standard equipment year after year. When the Government soughta reliable spark plug for aircraft service, army engineers sub- mitted their problems to all spark plug makers. What was the result? AC’s were selected as standard equipment on all Liberty and Hispano-Suiza Airplane Motors. Here again AC met the emergency. That’s about all you need know about spark plugs. You may be sure that the spark plugs which have met the exactions of these master engi- neers will serve you unfailingly also. Champion Ignition Company, FLINT, «Michigan AJA LTV YASS Ye

These manufacturers use AC Spark Plugs for factory equipment

Acason Trucks Chalmers Federal Trucks Jumbo Trucks Maytag Owens Light & Rutenber Motors Acme Trucks Chandler Frontmobile Kalamazoo Trucks McLaughlin (Can.) Power Plants Samson Tractors Advance-Rumely Chevrolet F-W-D Trucks Kent Concrete Menominee - Packard Sandow Trucks Tractors Chicago Trucks Gabriel Trucks Mixers Trucks Paige Saxon Ahrens Fox Fire le Genco Light Keystone Trucks Midland Trucks Pan-American Scripps-Booth rucks Commonwealth . B. S. Motors Kissel Kar Mitchell Parker Trucks Scripps Motors American-La France Conestoga Trucks G.M. C. Trucks leiber Trucks Moline-Knight Paterson Seagrave Fire _ American Trucks Continental Gram m-Bernstein <lemm Trucks Moreland Trucks Patriot Trucks Trucks Anderson Motors ., trucks Knox Tractors Napoleon Trucks Peerless eneca Apperson Crane Simplex Gray Dort Coeh Trucks Nash Phianna Signal Trucks Appleton Tractors Daniels Hackett K-Z Trucks ational Pierce-Arrow Singer Auburn Davis Hall Trucks La Crosse Tractors elson o Smith Motor Avery Tractors Deere Tractors arvey Trucks Lalley-Light elson Tractors Pioneer Trac‘ors -Wheel Beck-Hawkeye Delco-Light atfield rty Nelson & Le Moon Premier Standard “8” Trucks Diamond T Trucks Haynes Liberty Aircraft Trucks Ranger Trucks Standard Trucks 3etz Trucks Diehl Trucks erschell-Spillman Motors Netco Trucks Reo Stearns-Knight srockway Trucks Dodge Brothers Hispano-Suiza Locomobile Noble Trucks Re Vere Stearns Tractors suffalo Motors Dort Howcll Tractors Maccar Trucks Northway Riker Trucks Sterling Engines sugatti Duesenberg Hudson Maibohm Oakland Robinson Fire Sterling Motors Suick Motors Hupmobile Marmon Old Reliable Trucks Sterling Trucks Cadillac Eagle Tractors Jackeon Master Trucks Trucks Rock Falls Stewart Trucks 3.1. Case T. M. Co. Essex Jordan Maxim Fire Trucks Oldsmobile Rowe Trucks Straubel Engines

U.S. Pat. No. 1,135,727, April 13, 1915. U. S. Pat. No.1,216,189, Feb. 13, 1917. 89 Sullivan Trucks Swartz Lighting Plants S-S-E-Co. Tiffen Trucks Titan Trucks Tower Trucks Trego Motors Universal Trucks United States Motor Trucks United Trucks Veerac Motors White Whitney Tractors Wilcox Trux Wisconsin Motors Wolverine Tractors

Other Patents Pending.

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“Ts dish-washing hard? —not in our house! HEN closed, you use the Western Electric Dish- }99 washing Machine as a kitchen table. Into it, when open, you put your finest china, glassware and silver —all safely arranged in wire racks. Put in hot water with soap or cleansing powder, turn on the electricity, and in a few minutes the dishes will be thoroughly clean. Repeat the operation with scald- ing hot water and the dishes will quickly dry them- selves. This practical dish-washer will last many years-— every day proving that electricity makes easy even the hardest and most disagreeable of household tasks. Five cents worth of electricity will wash the average family’s dishes for a week. It is wonderful—that’s why you will want to see it demonstrated. The world’s largest distributor of electrical household helps guarantees this practical labor saver. Be sure to see it demonstrated. Weslern Electric , / Dish-Washing Machine WESTERN Write for Booklet No. 33-AT, and we ff ELECTRIC will tell you where you can see a CO., Inc. this Dish-washer demonstrated. i entlonnen : Please send me Booklet 7 _No.33-AT, describing the new Western Electric Dish- Popular Science Monthly 18 ins. long. The frame is of any thickness wood, approximately 3 ft. long by 1 ft. wide at the front, and 1% ft. at the rear, supported by legs so that the top is 11% ft. from the floor. In the front ine an opening is cut 3 ins. wide by about 8 ins. long (A in diagram). To one side of this ig secured a piece of iron B, broader at the top than at the bottom, and saw toothed. C is a flat iron bar about 21% ft. long by 1 in. or 114 in. wide, twisted at D, swung on pivot G, and extending through the opening A D is small round iron bar with claw ends, pivoted to the flat bar at H. To operate, place bicycle upside- down, with the saddle resting upon the gunny sacking F and_ handlebars through notches E. Place ciaws D over handlebars to either side of center post. With foot at J press down spring bar C until the claws hold the handlebars tight, and secure by catch- ing the bar in one of the notches in the flat iron plate-—SAMUEL W. BEACH. Repairing an Unsteady Smokestack HEET-IRON smokestacks fre- quently become weakened and thin about half way to the top, due to vibration and other causes. This often happens while the upper and lower halves of the stack are still in excellent condi- tion. To insert two or more new wf sections in the center of the stack is an ex- pensive and dif- ficult proceed- ing. And to patch a defect is almost as bad as putting in new sections. Thereisa Y way, however, 3 to do the repair- ing with but . The chimney brace is = ——— firmly bolted around : the stack and wired and time taken. to the roof carefully The repair con- sists of a framework of flat, wrought- iron bars, bolted around the pipe in such a way that it will brace up the weakened portions. The frame-work should be long enough to reach several feet beyond the weakened section in either direction and should be bolted firmly on the outside of the stack. The brace-consists of three rings of flat bar iron connected by several up- right bars of the same material. It is made in halves upon the ground and then hoisted into position and bolted together. This brace should fit the stack WESTERN ELECTRIC COMPANY, Inc. 7 washing Machine. snugly and the two halves should be New York Chicago “a drawn as tightly as possible. The Kansas City San Francisco NAME method is equally good on small or Other Distributing Houses in Principal Cities rs SIRS large chimneys, and, being simple and v 38 cheap repair, should commend itself to repair men.—DAVID BAXTER.

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—_— M ee ri hee Cor How the Chalmers Hot-Spot Ram’s-horn Cuts Down EVENTY-FIVE per cent. of automobile troubles are due to faulty lubrication. The lubricating oil is not at fault. It is the gasoline of today. Expensive lubricating oil is poured into the crankcase to be splashed up into the engine cylinder. Raw gasoline leaks down from the cylinder, trickles into the crank- case and “cuts” the lubricating oil. That means scored cylinders, ‘“‘knocks,” carbon deposits, cut bearings, heavy repair bills, perhaps a ruined engine. The gasoline is to blame. It cannot be consumed by the engine. It is the wrong kind of gasoline. The right kind, the kind that the engine will burn completely, is too scarce, too expensive for general use. There is only one way out of the diffi- culty. That is to design the engine so that it will burn the kind of gasoline generally obtainable. For two years the Chalmers engineers have been at work on this problem. After much research and countless tests they have at last produced the ideal automo- bile engine. The ideal engine has a Hot Spot mani- fold. The unvaporized drops of fuel strike that Hot Spot. Instantly they are con- Repair Bills verted into vapor. They cannot enter a cylinder as so much raw gasoline to de- stroy the lubricating properties of the oil in the crankcase. Think what this means. It means that you get all the power that your engine is capable of delivering. Starting is easy. Your repair bills are cut down because in the Chalmers engine the chief cause of carbon “knocks” and worn bearings has been removed. The Chalmers engineers have gone fur- ther. In addition to providing the mani- fold with a Hot Spot, they have given the manifold a Ram’s-horn shape, so that it is free from the sharp angles that check the onward flow of the swiftly moving mixture to the cylinders. The curves are easy. Each cylinder, therefore, receives ex- actly the right amount of mixture. One cyl- inder is not starved and another surfeited —the usual way. This means that the Chalmers is the cool- est, easiest running en- gine to be found today. This is the fifth of a series of six bul- letins in which the wonderful features of the new Chalmers will be explained. i ni | i ql

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FIT YOURSELF FOR THE BIG JOB Don’t hesitate any longer. There is onal for trained men now than ome gel greater opportunities—bigger pay—more rapid ad- vancement. It’s training that counts now—accurate knowledge—a complete grasp of your trade. Drake’s neciesca Books Mechanical FOR HOME STUDY pave the way to the fat pay en- velope Written in non-technical language that any the price of any book listed books post paid—you keep — ‘ave days—if not entirely satisfied return the ks and your money will be refunded in full. AUTOMOBILE BOOKS Brookes’ Automobile Handbook. 1919 edi- Soa, he E Brookes, et size. Leatherette . $2.00 Automobile Ignition. IGNITION i By H. P. Manly | i Pocket size. RAAINL: ep i Leatherette . $2.00 Ls MANLY Automobile Start- ing and Lighting. By pen. . 1919 edition ocke: ——y Leathere $1.50 The Ford, Motor Car one Truck and Tracto: oe ms ay ment 9 y Leatherette . $1.50 Automobile. Cate-

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Popular Science Monthly The How and Why of a Carburetor

SS etn _- en en —— ’ . URING the last few months we have heard much about the scarcity and high cost of gasoline. At times the situation really looked criti- cal, but recent developments have cleared the way, at- least for the pres- ent. The oil chemists have devised processes whereby more gasoline can be obtained from the crude oils. The engine and carburetor designers have perfected designs that use lower grade fuels and give more power per gallon of fuel used. The car owners are be- coming more familiar with their ma- chines and are a = able to get a ~~, WN greater mileage ; . from the fuel that they use. There are many new carburetors and fuel-saving devices on the market today. Before any of these can be discussed in an intelligent manner one must get the fundamental principles of the carburetor clearly in mind. A carburetor may be defined as a device for vaporizing the fuel and mixing it with the proper amount of air for combustion in an internal- combustion engine. From this defini- tion it is evident that the requirements of the carburetor are two-fold. Vaporization of the fuel is very im- portant and has become more so with the use of the low-grade fuels, which are hard to dissipate into a vapor. Several distinct reasons can be cited as to why complete yeporuation is so necessary. If an engine is to run smoothly the explosions must be equal in all of the cylinders, and to ensure this equal charges must be delivered to each cylinder. This cannot be done unless the fuel is completely vaporized, as may be “YJ clearly seen from the example given in Fig. 4 1. The openings A and B represent the con- B nections of the inlet ( manifoldtotwoadjoin- !

Manifold connections

c Y&

ing cylinders, and C a connection to the main part of the manifold | leading from the car- How the mixture buretor. If the inlet entersthe cylinder valve at B is open the charge is being drawn in through C and is entering the cylinder at B. Now if the fuel is not. completely vaporized,

92 By S. E. Gibbs or is partially carried along as small drops, the heavy portion will have more momentum than the air and fuel vapor, and will tend to go straight ahead, just as an automobile does on a corner, and into the passage toward A. Therefore not enough fuel would enter the cylinder at B, and the mix- ture would be weak and probably the cylinder would not fire. Inversely, the charge taken in through A would be the normal mixture plus that which was carried past B, and would be too rich. This explains why a motor misses when starting on a cold morning. If the fuel is taken into the cylinder as a liquid, part of it will be deposited on the-piston head and cylinder walls. The part of it that strikes the walls will mix with the lubrication oil and make the oil thin and interfere with its lubricating properties. Part of this oil and gasoline will get by the piston and into the crank-case and thin the oil in the sump. In some cases this takes place to such an extent that the amount of fuel that enters the sump is more than the amount of oil that is used and it seems the en- gine is using no oil. Thisis very dangerous and Fal i a Device for experimenting a fresh supply added often until the difficulty is remedied. The oil that remains in the cylinder partially burns and leaves a heavy deposit of carbon, which will in time cause the motor to knock and necessitate its being dismantled for the removal of the carbon. Rapid and complete combustion must be had if the engine is to develop maximum power with a minimum of fuel. Manifestly no power is obtained from fuel which is not burned. The gasoline must be completely vaporized and well mixed if it is to burn properly. Then no carbon deposits will be left from the fuel but carbon can still be formed from an over supply of oil reaching the cylinders or from the dust which is drawn into the cylin- ders. Complete vaporization is attained and maintained in two ways; namely, first by spraying the fuel and breaking it up so that a large surface is exposed

pal

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ve ie] ht rd | Id iX- Lat sed

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Popular Science Monthly ADE hee rahe You can’t think of “delicious” or “refreshing” without thinking of Coca-Cola. You can’t drink Coca-Cola without being delighted and refreshed. The taste is the test of Coca-Cola quality—so clearly distinguishes it from imitations that you cannot be deceived. Demand the genuine by full name —nicknames encourage substitution. THE COCA-COLA CO. ATLANTA, GA. hy

—— 2 [ao 2 Sa ise ill Se Fee? oy, | ai Tae _ enn al 5 a mm aly? GA” cee -attinemamesaall

LR ge a -emnagnancpenneneypnementeeneencaeee 94

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September, 1919 to the air, and second, by heating the fuel or air. Heating may be accom- plished in several ways. The fuel could be heated but not enough heat can be stored in it to give good results. Normally a carburetor becomes cold due to the heat absorbed from the metal when the fuel vaporizes; this must be counteracted. The air which is to be taken into the carburetor is often passed around the exhaust pipe and heated enough to vaporize the fuel. The intake manifold is often heated by passing hot. water around it, and in this way the fuel is prevented from cooling and condensing, and any drops of fuel which strike the manifold wall are quickly vaporized. . However, P only sufficient heat should be applied For men who don é. to get complete vaporization, as addi- smoke pipes and kid-. : tional heating will lower the maximum dies who don’t believe power the engine will develop and ma ry Santa Claus—we cause pfé-ignition. here by pass resolu- The fuel is sprayed through a small tions of sympathy. opening or jet and is thus broken into small drops. This process can be qabooh fe made more effective by increasing the 4 suction on the jet and thereby making it possible to deliver the fuel through a smaller jet. A venturi tube is used ] for this purpose in most designs. A There S Tast e cross section of the choke tube is By Oo It! shown in the sketch number 2. The , air enters at A and flows through the small openings at B and out to the It’s easy to find a engine through the passage C. The : a ib ie cian te Gow at Blok mild tobacco that’s velocity at the narrowest passage tasteless There are through the venturi tube. As the : velocity increases the pressure de- full bodied tobaccos creases so the suction on the jet will be that are strong. But increased by speeding up the air in this manner. It may be rather hard for some to conceive the phenomenon of the suction increasing. The experiment shown in sketch number 3 may make this point clearer. Take two pieces of wood, 1 in. square and 10 in. long, and lay them on a ae or nage a. table about 6 in. apart. “tes She Telhness Then lay a sheet of an paper across them and blow beneath the paper. The suction caused by the moving air will draw the paper down to the table. When a device for vaporizing the fuel has been obtained the work is only half done as the fuel must be mixed with the correct amount of air before it is ready to be taken into the engine. There should be 12 to 15 parts of air by weight to one part of fuel vapor to obtain the proper results from the engine. If over 15 parts of air-is-mixed with, 1 part of fuel the mixture is too lean | and various troubles will result... The motor ‘will begin to miss-and often-|’ . will back-fire through the carburetor; | . which may set the latter on fire.’ ; | |: If less'than'12°parts-of air is mixed --- with 1 part of fuel the mixture is too rich. Very rich mixtures will not Copyright there’s one that’s cool as a cucumber and lively as a cricket. And it’s friendly. That’s Velvet. Have some? N N CDSS SSS Hp § N N N iS y {

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a es Se ne ce ot

AAA TM I Hi | pe esoecceenees

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THE STANDARD WHITE INK Favorably serviceable as a Water Color or Air Brush Spray Of special interest and value to Photographers, \ for photo books; Engineers, for blue prints; Artists, Card Writers, etc. 2 |) By return mail on receipt of 25c in coin or stamps J. W. JOHNSTON New Arts Building Rochester - - New York

We want every man who shaves to write us for articulars about the Vibrating Electric Razor. o matter where you live, in the city or on the farm, the Electric Safety Razor will solve your shaving troubles. VIBRATING ELECTRIC RAZOR CO. Dept. 137, Omaha, Nebr.

The O88 Sor dem Tooth Brush etio™

| the motor to run

Popular Science Monthly burn completely and a poisonous black smoke will be exhausted from the engine. The motor will soon carbon- ize badly and will very easily overheat, A rich mixture will cause the motor to lose its snap and it will not develop its full power. There- fore, in adjusting the carburetor,the mixture should be thinned down un- til the motor be- gins to miss and then increased just enough for

smoothly and pick _ hog a of carbu- up well. etor is losing prestige Any ratio of fuel and air may be obtained at any given suction or engine speed by adjusting the size of the air and fuel openings. Naturally, as we use 12 to 15 parts of air to one of fuel, and as air occupies about 800 times as much space as the fuel, weight for weight, the fuel jet will be much smaller than the air passage. In automobile practice the car- buretor must give the correct mixture at all engine speeds. The speed and the power of the engine developed are regulated by the amount of the mix- ture that is taken into the cylinders. This amount is regulated by a throttle, as shown in sketch number 4. The mixture is sucked through the mani- fold A into the cylinders and the valve or throttle B regulates the amount of mixture that enters the engine. The suction in the mixing chamber is regulated by the throttle. That is, when the throttle is opened the suction on the fuel jet is increased and also more air is drawn into the carburetor. If the amount of increase in air and fuel were in proportion a carburetor would be easy to design. But this is not the case, as the flow of fuel in- creases faster than the flow of air and the mixture tends to get too rich at high speeds and too lean at low speeds. There are a number of ways to correct this difficulty and therefore we have many designs of carburetors. How- ever, there are only four fundamental designs and the various carburetors are one of these or a combination of them. The design that would probably be the first to suggest itself would be a needle valve to vary the size of the fuel jet. A simple carburetor of this type is shown in sketch number 5. The needle valve which regulates the size of the fuel jet is regulated by an eccentric which is on the throttle shaft. This type is not very common, but it is used in several combinations with other designs. Another type, which was very pop- ular a few years ago, especially in America, but which is losing ground lately, is the auxiliary air valve type. ‘A simple view of this type is shown in

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os @ them 1 Rehm ORS 4 oo oO oo ce _. «a — | - BR e. 6 - Oe ee September, 1919 ae # . + | : iv ‘ me Hitt " Wi MAI Hi HU MI Hi} i WAHT HN “Tl say it is!”’ Prince Albert certainly will put some frolic into that ~ | pet pipe of yours! To pack that joy’us old jimmy Fo brimful or roll a makin’s cigarette and hit’er up a notch or two is just going right over the top with your eyes PI ( wideopen! What P. A. will do for your taste and tongue you sure ought to know! Like the gentleman from ni Mul Al ‘ }: “ ' into your smokesystem! | : , : You’ll say it is, too! Sparrow’s Point you'll call P. A. a good egg! You'll | , smoke a pipe full and talk a bucket full—Prince Albert. i i is oy. | is such a great, big bunch of smokesunshine! C ii i x Hi i i i | | You'll quick catch the P. A. cue that it can’t bite or i | ie M i = i '| parch; that Prince Albert’s exclusive patented process | s ceo a Le op of | || frees it from bite and parch! And makes the sky the i Hi i i i ini : ied ‘| smoke limit! Give Prince Albert high pressure for ze sal | pound i , | flavor and fragrance! Put P. A. through your little old : wit vith h ce se moisten ten ih te ii taste-test-mill—and—just let that q-u-a-l-i-t-y percolate | mit ij whi R. J. Reynolds Tobacco Company, Winston-Salem, N. C. | Copyright 1919 by R. J. Reynolds Tobacco Co, | ij Hi | | H 1 ll i (!

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Regardless of cracked porcelain, dirty, sooty plugs, or weak ignition, Dunbar double gap sparkers deliver a hot fat spark to the firing chamber of your motor and keep the firing end of the plugs clean, free from carbon and oil. Dunbar double gap sparkers give more power, greater speed range, and elimi- nate bucking and jumping. A glance tells instantly if any plug is missing and why. Either the coil is faulty, a wire is broken, or loose, or the spark- plug is worn beyond further use. Dunbar double gap sparkers are different. They are built on the right princi- le and of quality material. The double gap insures hot, NOW IT fat sparks, possible SPARKS Only with its use. READ the guarantee. Order a set today. End your spark plug troubles now. Attached quickly and eas- * oad § ily without extra installation expense. Set of 4 Parcel Post paid, $5 Dealers and Sales Agents—Write for our attractive selling proposition. Lig F. R. X. per. co. Finding, your \ Yj orxKON / ELpoR 00 Vi This is for you! is for you! A booklet telling you how to find your pen- cil—a pencil that will ease and quicken your work and make it more pleasant. ELDorADO the master dmming pencil” Write us today for this bookle-—FREE. Enclose 15 cents if you desire samples worth double the money. Please mention your dealer’s name and the kind of work you do. j Pencil Dept.120-J, Jersey City, N. J. Canadian Distributors A. R. MacDougall & Co., Ltd., Toronto ARMATURE AND MAGNET WINDING By Horstman & Tousley Anecessary book for electricians. Full facts and diagrams, $1.50 postpaid. Popular Science Monthly, 225 W. 39th St., New York sketch number 6. An air valve is located above the venturi tube and below the throttle and is opened at high speeds to admit air to weaken mixture and to cut down the suction on the jet. There are two types of auxiliary air valves; one in which the valve is operated by a link motion from the throttle shaft and one which is held shut by a spring which will allow it te suck open at high speeds and admit enough air to correct the mix- ture. Both types are in common use and in one popular design they are used in combination with part of another type. In a design which has won consider- able fame on the speedway, and is gain- ing ground rather fast with the general public during the last few years, the size of both the air passage and the fuel jets are varied. The advantages claimed for this type are that it breaks up the fuel very well, gives a very homogeneous mixture, and very good mixture ratio at all speeds. One class of this type is known as the multiple jet carburetor. When running the motor slow one jet and one air passage are used. When it is speeded up another jet and air passage are added, and so on, until the correct amount of mixture is delivered. Some multiple jet carburetors have as many as 16 jets. The other class uses one jet which is controlled by a meter- ing pin, and an air pas- sage which is regulated in accordance with the fuel supply. There are many designs along this line, afew of which have been extensively used during the last few years. The compound noz- zle type is most used today and has been popular in Europe for some time. It is simple, easily manufactured, and almost fool- proof. In this type it is common practice to use two jets of opposite characteristics. In one popular de- sign the main jet supplies about ninety per cent of the fuel required to give a correct mixture at high speed, and ten per cent at low speeds. A com- pensator jet is used which supplies ten per cent of the fuel at high speeds and ninety per cent at lowspeeds. Thus a correct amount is supplied at any speed by the two jets. The layout of this device is shown in sketch number 7. The compensator nozzle is located around the main jet but it is in no way connected with it. The fuel is sup- plied to the compensator nozzle from a well which is open to atmospheric pressure. This well is fed from the bowl through a small jet which is located in the bottom of the well. The fuel flows into the well by gravity as the fuel level is higher in the bowl. As the engine speed is increased the suction is increased on both jets, but it does not affect the amount of fuel 98 NN Cue Ww CM SS SS S N A simple carburetor Say Good-bye to Laundry Bills § | Sensible Neckwear Why spend $18 to $25 a year for collars and laundry bills when $2.10 will cover the entire expense. Six Challenge Cleanable Collars will give you collar comfort and economy for twelve months. They never wilt and when soiled may be instantly cleaned with a little soap and water. Always ready to =} wear. Made inall popular styles and sizes. Ask your dealer or send 35 cents for sample. State size and style. THE ARLINGTON WORKS Owred and Operated by E. I. du PONT de NEMOURS & CO. Wilmington, Delaware | 1 HOW TO SAVE COAL! PUT A CARBURETOR ON YOUR FURNACE-DOOR —e2 2 OF ORY + eS ae Wf see eeeeerrareerora, Te: 4 Soy STOO WSS SSAA SSS SRST S SST SST ETE INCREASES HEAT 25 to 50%! BURNS THE SMOKE: REDUCES ASH, SOOT, LABOR and FUEL BILLS. Easily put on any Heating System, Stoves, Furnaces, Water Heaters or large Steam Plants without disturbing the Fire. No change in Plant or Fuel: Entirely out of the way in Firing. USERS say “Results Wonderful.” Write for literature and Low Direct - from - Factory - to - You - Price GET READY NOW FOR WINTER! WEST FURNACE CARBURETOR CO., 1417 Glenarm St., Denver, Colo. AGENTS WANTED Free Book- Send for this Free 118 Page Book. It tells how you can gain a thor- ough knowledge of law in your . spare time. as 40,000 others are doing. Splendid op- portunities in the profession of law. Busi- pe ness today needs law trained men. Free Si book ~ives experiences of successful law trained men, and tells how you can read law under guidance of Ex- President Taft and 80 other eminent authorities. Blackstone Institute Dent 126, 608 S. DearbornStreet Chicago ENORMOUS PROFITS START GROWING MUSHROOMS Le: the latest_authoritative way to k stil ;pigwer Profits than you over thouwht possibie or ever made RTO" rm Add $10 to $75 a week to your income. Anyone, men, women and children can do it in spare ents, cellars, sheds, bores, ete Bo “WA ,, book of expert authority, “The Truth About Mushrooms.’’ Write to BUREAU OF MUSHROOM INDUSTRY Dept. 565 5005 W. North Ave. Chicago ELECTRICITY MADE SIMPLE A book devoid of technicalities. Simple, plain and understandable. $1.00 Postpaid. Ponular Science Monthly, 225 W. 39th St., New York Popular Science Monthly . pace erences bP 2 AIR ih A Se

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——_— llr TOC SS Ride a Bicycle NSPEC TION by the Chief. The Bicycle Corps is ready. Every boy spick and span. Every bicycle clean and shining, with tires sound and well inflated. Good scouts know that tires are mighty important. You couldn’t afford to have a tire go flat on urgent duty. Line up the bicycles in any ship- shape outfit and you will find a big majority of them are equipped with United States Tires. That’s because the boys with ex- perience: know that United States Tires are good tires. They are al- ways reliable and give long mileage. Boys who have looked into the matter know that these tires are made by the world’s largest rubber manu- facturer, the same company that makes the famous United States Tires for automobiles. They know the rub- ber comes from Sumatra where the United States Rubber Company has a plantation of 100,000 acres. They know this company has been making good tires since bicycles were first invented. Remember these things when you get a new bike or when your old wheel needs new tires. Take a tip from experienced riders and be sure to get United States. There are nu- merous styles from which to choose both clincher and single tube. United States Cycle Tires are Good Tires

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...Building Contractor

iti eis [eye] 5 COURSE IN TWO YEARS YOU ARE BADLY if you lack HANDICAPPED HighSchool training. You'cannot attain business or social prominence. You are barred from a successful business career, from the leading professions, from well- paid civil service jobs, from teaching and college entrance. In’ fact, em- ployers of practically all worth-while positions demand High School train- ing. You can’t hope to succeed in the face of this handicap. But you can remove it. Let the American School help you. FIT YOURSELF FoR A BIG FUTURE This Course, which has been prconend by some of America’s leading pro- | fessors, will broaden your mind, and make you keen, alert and capable. It is complete, simplified and up-to-date, _ It covers all sub- jects given in a resident school and meets ali requirements of a High School training. From the first lesson to the last you are ly examined and coached. USE SPARE TIME ONLY ldost people idle away fifty hours a week. Probably you do. Use only one-fifth of your wasted hours for study and you can remove your present handicap within two years. You ony the lessons and the knowledge agp gain will well repay the time spent YoU RUN NO RISK So that you may see for yourself how thorough and = complete our training is, we invite you to take ten lessons in the High School Course—or any course of specialized training in the coupon below—before decid- ing whether you wish to continue. If you money. in full We’ absolutely guarantee ney i @ absoi guaran satisfaction. that basis you owe it to "Check and mail the coupon NOW for full \ mail the coupon or particulars and Free Bulletin, AMERICAN SCHOOL CORRESPONDENCE Dept. H -756 Chicago, Illinois

Explain how I can qualify for the position checked. ...High-School Graduate ..-Lawyer . . .-Electrical Engineer ..-Business Manager ..-Elec. Light & PowerSupt. ...Certified Pub. Accountant ..-Hydroelectric Engineer ... Accountant and Auditor ... Telephone Engineer ...Bookkeeper ... Telegraph Engineer . .. Stenographer .., Wireless Operator ...Fire Insurance Expert ..- Architect .. Sanitary Engineer ...-Master Plumber ...Civil Engineer ..-Heating & Vent. Engineer .. Structural Engineer ...Automobile Engineer ...Mechanical Engineer ...-Automobile Repairman .. Shop Superintendent ...Airplane Mechanic . .. Steam Engineer ...General Education Course ..-Draftsman and Designer ...Common School Branches RES Senne sss ce sccctabosee es ee Address eee meee HEHEHE HEHEHE EHH EEE EE EEE EEE

that is delivered from the compen- sator as no suction is exerted on the jet because the well is open at the top. If this jet was used alone it would tend to give too lean a mixture at high speeds. Due to the abundance of fuel in America little attention has been paid to economy. Production has played a much larger part in the designs than it should have done, for often a change that saves fifty cents in the cost of the carburetor has wasted many dollars worth of fuel during the life of the car. It is evident that with the increased cost of fuel many changes will take place and probably we are starting on a new era of car- buretion. Heating devices will re- ceive much attention, as it is necessary to use lower grade fuels. It is hard to N

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AAAAARAAASARASANNS CP SSSSSSSSS Ny N

The compensator jet, which regulates the fuel predict which type of carburetor will win out, but the one that does must give the correct mixture at all speeds and loads. Remedying Motor Drive Trouble ECENTLY trouble was experi- enced with an eight-pole, 450 h.p., synchronous motor running at 60 cycles and 900 r.p.m., with a driving pinion having sixteen teeth. When the motor was started meters con- nected in the circuit showed that the load rose and fell in regular periods, increasing in value with each period until the circuit breaker would trip out. Under these conditions operation of the machine was impossible. An examination brought out the fact that it was a case of harmonic load building brought about by the fact that a 16-toothed pinion had been selected to run on a shaft driven by an eight-pole motor. The frequency of the motor and the impulses to the machine driven by it being too nearly alike caused a resonance in the system, and this, being intensified by irregular- ities in the gear teeth, caused the load to fluctuate and increase beyond control. The trouble was finally remedied by putting a small fly-wheel on the set to take up the periodie load fluctu- ations.— PETER J. M. CLUTE. 100 You can start in the same business for little money. - Popular Science Monthly " He Made $809 First Two Months

Pi ° F < # a 3 Hed money + of t io tanto game. make for you to start. i cay American Box Ball A 5c game that appeals to everyone, women as well ag men. More fun than o; inary bowhing. Practi ally 100%, profit. No operating exDenseg —no helpers, no wages to pay, Pins are reset and balls ro. turned automatically. New automatic electric lighted score board makes a big hit, Be the first in your locality with Box Ball Alleys. Very little cash needed. Pay as the Alleys earn. * Box Ball has ¢ Write stay! See for yound the money that others are maki Write us for the amazing facts and full description of the equip. ment and particulars of our payment plan. Write today, 4 post card willdo. No obligation, American Box Ball Co, 809 Van Buren St., Indianapolis, Ind,

{ LIBERTY BRAND FERRO-CERIUM ! Or SPARKING METAL Ferro-Cerium is the metal used in cigar lighters to produce the spark showers. It has been developed to such an extent that the results obtained are marvelous. We are anxious to discover newuses, such as sparke ing toys, safe and sane fire works, technical uses, etc. Any ideas used will be paid for. Write at once for details, sample of Ferro-Cerium, and rules of contest NEW PROCESS METALS Co. 50 E. 41st St., New York

in avenient — stalled. Convenient to move. —_ nya of easily S garbage. vents fly breeding and water con- tamination. Provides sanitary, odor- less toilet in home protected from cotd ff and stormy weather. Only closet with porcelain container. E-sily cleaned. € Approved by U.S. Health Bureau. 30 We want at least one well-soq ted ambitious driver in_ every locality to nays cng and ,senl 0 —— aoe . TOO: e vens Beadless Tires Dost miy half as much, yet guaranteed FF They’ re also oversize, better lookin easier riding. We help you establish @ substantial flourishing business of your own, the weekly profits from which will amaze you, e show you how and ive you ever help. if _ are ambi- ious to build a big business of \) < doo Toilet (the Comfort Closet for Homes, Summer Cottages and Camps. Entirely odorless. Scientifically ven- tilated. Strong chemicals dissolve contents; kills all germs. Easily in- Con- iii i qa HH eek]:

$itow y. i Serine te for booklet—FREE. Samfort Chemical Closet C0.,1379 Factories Bidg., Toledo, 0.

CSR ARB: TTI

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my F. oe x S PETES Pd 1 pete j iba Fe. Cy ters to ped to velous. » etc. of September, 1919 “Bingo! . . «he Fiery Little Columbia 1s Always There With the Ignition Punch!” UARRY BLAST CHARGE and auto engine gas are alike to the Fiery Little Columbia. The power’s in the fuel; but it takes the Columbia hot spark to set it to work. That's a regular Columbia job— releasing energy by ignition. THE DRY BATTERY HAT a marvelous little bundle of big ability the Columbia Dry Battery is! And what a multitude of uses! It makes bells jingle and buzzers buzz; whirls the youngsters’ toys into a riot of fun; gives snap to telephone talk; puts a swift and powerful kick into the ignition of autos, trucks, tractors, farm engines, and motorboats. THE STORAGE BATTERY [N the storage battery field the name Columbia means definite power guaranteed for a_ definite time. Columbia Service Dealers and Ser- vice Stations are everywhere—they make that guarantee good. Step in and let them tell you how the Columbia Storage Batteries are distributed, and how the Columbia Service Plan insures that the motorist shall have the full service to which his original purchase entitles him. Columbia yoragepatteries -

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Release the Talent in Your Pencil Everybody has the ability to draw. True, some have more ability than others—but that is because. it has been developed. Just as you have been taught to read and write, you. can be taught todraw. It’s sim a question of the proper training. y stick at a routine job, wasting your life. away, when there is a crying demand for trained illustrators—car- toonists—and designers? Our won- detrful NEW METHOD of thoching art by mail has qualified hundreds o our students for high-salaried posi- tions. Under our instruction, your undeveloped ability will flow forth in streams of saleable pictures, and you will have A Career— Not a Job A career iso to you as commercial artist that definite possibilities. There is no future for you in a “‘job.’*, There are thousands of big paying Artist's positions open right now. And these positions are actually going begging because of the scarcity of t ed artists. Magazines, news- papers, advertising agencies, business concerns—all are lookingfor menand women who can handle their illus- trating. With the tremendous boom in both foreign and domestic business, commercial art is more in demand than ever,—and that demand is grow- ing every day! Get in this fascinat- ing game NOW! $100 for One Drawing That is what many of our students are now getting for one drawing! Many, after completing this wonder- fulcourse, have evenstartedinat $60a week! Often, even before the student has finished his course, he has made more than enough through the sale of his drawings to pay for his tuition. Why? Because he learned to draw under the personal instruction of one of the country’s foremost commercial artists — Will H. Chandlee. The Chandlee system does away with all superfluous technique and entangling hindrances of the ordinary art school. It brings the principles of successful drawing right down to fundamentals in a course of instruction that can’t be beat. You can get all the benefits of studio instruction right in your own home,—and for just a few cents aday! VYourspare time is all that i; required. Our valuable book ‘How to Become an Artist’’ tells all abouc it. Send for it today! It's FREE! Free Book and Artist’s Outfit Mail coupon NOW for this wonderf! free book ‘‘How to Become an Artist.”’ Contains full particulars of our FREE ARTIST’S OUTFIT OFFER, and special terms for new students. Also contains many drawings by our students, showing their remarkable progress. Book just full of valuablein- formation to you. Send for it NOW! Washington School of Art, Inc. 1119 H Street, N. W. Washington, D. C. (coupon) Washington School of Art, Inc. 1119 H Street, N. W. Washington, D. C. SSX ( r\ a) cs 4 SSS = SS ill ONO AA SSS XS lh {* te % SS. SSS ] WOM IQ ll SS WSS DCR TW S kg SS MS NS WS . i GZ me an Please send me, without cost or obligation on my Artist.” part, your free book “ dbs ccncssccecccccéaanenno Popular Science Monthly Bi se What Can You Do with the Exhaust of a Gasoline Engine? The Popular Science Monthly will pay fifty dollars for the best answer Wi can you do with your engine exhaust? Is it an a utomobile, boat, or stationary engine? We know of one man who heated his greenhouse with the exhaust from his stationary engine. There are, of course, many other uses for it, and we want to know in how many practical ways it can be applied to save time and money. The appliance must not retard the engine’s speed or power and must not involve the operating of another engine. Tell us! THE POPULAR SCIENCE MONTHLY offers three prizes,—a first prize of $50, a second prize of $25, and a third prize of $15, —to be awarded in accordance with the rules set forth below: Rules Governing the Contest (1) Contestants are not limited to the number of methods of util- izing the exhaust which they may describe, but only one method can possibly win the first prize, only one the second, and only one the third. The contest is open to everybody. (2) The method must be clearly shown either in a photograph or in a drawing. If a drawing is sent in, it need not be made by a skilled draftsman. It is sufficient that it should be intelligible. While pencil sketches will be con-. sidered, contestants are request- ed to make their drawings in ink on bristol-board. The views should be sufficient in number to set forth the use of the engine’s exhaust very clearly. The con- testant’s name and address should appear on each sheet of drawings. (3) The drawings or photo- graphs must be accompanied by a description, preferably type- written, in which the method is clearly given. It must be written on one side of the paper only, and it should not be more than 500 words in length. The name and address of the contestant should appear in the upper left-hand corner of the first sheet of the written description. (4) The drawings and descrip- tion entered by contestants must be received by the Popular ScIENCE MONTHLY not later than 5 P. M. on Friday, October 31, 1919. (5) The judges of the contest will be the editors of the PoPULAR ScrENCE MONTHLY. 102 (6) The first prize of $50 will be awarded to the contestant who, in the opinion of the judges, has suggested the simplest and best method of utilizing the exhaust of a gasoline engine. The second prize of $25 will be paid to the contestant who sub- mits a method next in merit. The third prize of $15 will be paid to the contestant who sub- mits the method third in merit. (7) The winners of the contest will be announced in the earliest possible issue of the PopuLAR SCIENCE Montuiy. A descrip- tion of the methods which win the three prizes offered will duly ap- pear in the pages of the PopuUuLAR SCIENCE MONTHLY, together with the names of the winners. (8) The editors of the PopULAR SCIENCE MONTHLY shall have the right to publish meritorious manuscripts which do not win a prize. The regular space rates will be paid to the contestants who submit the manuscripts thus selected. (9) When a contestant submits more than one method, the de- scription and drawing by which each is set forth must be sent as a separate unit. (10) Manuscripts or drawings will be returned to contestants if stamps are enclosed. (11) Send drawings and specifi- cations to the Engine Contest Editor, PopuLAR SCIENCE MONTHLY, 225 West 39th Street, New York City.

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September, 1919 UT 18 cents a package Camels are sold everywhere in scientifically sealed pack- ages of 20 cigarettes or ten packages (200 cigarettes) in a glassine-paper-covered carton. We strongly recommend this carton for the home or office supply cr when you travel. R. J. Reynolds Tobacco Company Winston-Salem, N. C. Camels supply cigarette contentment beyond anything you ever experienced! OU never tasted such full-bodied mellow-mildness; such refresh- ing appetizing flavor and coolness. The more Camels you smoke the greater becomes your delight-Camels are such a cigarette revelation! Everything about Camels you find so fascinating is due to their quality—to the expert blend of choice Turkish and choice Domestic tobaccos. You will prefer this blend to either kind smoked straight. You'll say Camels are in a class by themselves; they seem made to meet your own personal taste in so many ways! Freedom from any unpleasant cigaretty aftertaste or unpleasant cigaretty odor makes Camels particularly desirable to the most fastidious smokers. And, you smoke Camels as liberally as meets your own wishes, for they never tire your taste! You are always keen for the cigarette satisfaction that makes Camels so attractive, Your personal test of Camels will bring you a lot of real cigarette happiness. Smoke them today—then take this advice: Compare Camels with any ciga- rette in the world at any price! 103

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ave TIRES LIKE oS Be a TIRE SURGEON ly Make $2,500 to $4,000 Per Year Giving New Life to Old Tires A Haywood Tire Sur- geon can do more with old tires than was even dream- ed before the war. By the Haywood Method a Haywood Tire Surgeon can give 4,000 to 5,000 more miles of new life to a tire that two years ago would have been thrown on the junk pile. And it’s easy to learn. Stations are Needed F Everywhere 20,000,000 tires wearing down every day. By Tire Surgery you can quickly repair, rebuild and give new life to tires seemingly all worn out. Cuts, gashes, tears, bruises, broken fabric, every kind of an accident that can happen toany tire, inside or out, you can repair and save for long JS service. The chance to make money is simply wonderful. & S $2,500 to $4,000 a Year is Possible £& 4 : oS the truth youwouldn’t believe it. You would XS wee oo — be true.” But you can see what a great field there is ry ry for Haywood fire Surgery Stations—for this better way. > WRITE 10 Ny Send Today for My Free al I have ready to mail onthe day is your request,a , M. HAYWOOD, President % start in business-how ' © build u _ HAYWOOD TIRE & EQUIPMENT CO. Ceghat tocharge. in48 = Four Months This is Richard A. Oldham Mr. Oldham was te. greek cparater for Illinois Central Railroad for twenty yous He is fifty it years old. Oneday read one of my advertisements and the sa fgurmaathe enous wok asieend 3 uch as fwoe and One- years an Telegraph Operato: wood Method—how to | et fascinating f k—all about tires—how £7 torepair them by the Hay- x 2 preety ogee “ pms tas ore - vo hours yea can have, me IR: Please send me by return mail yo the whole pr ition ri foes look on the new Haywood Tire Surgery Methe i%e in front of you. and the details of your free school of tire repairing. @, coupon at the left. % M. Haywood, Pres. OH d Tire & | Name ___ % aocnent Ce. %, 1116 Capitol Ave. Address + indianapolis indiana ymplete Musical Outfits: : | ‘OU may have your choice of instruments and a complete musical outfit for a week’s free trial in your own home. Outfit includes case, music rack, all accessories, Ratrection book, etc, at factory Prices. A saving. Convenient Monthly Payments After trial return outfit at our expense if you wish. If you decidetobuy Warlitaet 2or 60 years has meant highest wey oe a ee ee ae ee ee Send this Coupon Worss:wenecs, Micon $60-pcge asaanes Cates eaten 8, a LY BLE : Cincinnati, Ohio Ave., Chicago, Ill. Co. Dept. 1206 4 = me Gita Wty are Cataee, 7 «Send te el een cna i Name Address gJnstrumentIam 104 Popular Science Monthly A Scaffold Replaces the Old Repair Pit HE repair pit is, at best, a most uncomfortable place to work in and to do away with it a large public garage has resorted to the method shown in the illustration. A trap was cut in the floor above the repair shop The car being repaired is on the floor above and the car to be repaired was driven over the hole in the floor. A scaffold, having a platform about 4 ft. square, was then wheeled into place, under- neath the hole. On the platform is a small bench with a vise, and drawers for nuts, bolts, ete. The result has been a saving in time, for the workman has a place in which to work, plenty of room to move about, and he can work steadily without having to climb down for ' tools.—W. R. Davis. Making a Pneumatic Seat for Shop Use ITTING eight or ten hours on an ordinary backless shop seat invites fatigue almost as great as if the worker had been standing instead of sitting. One way to relieve this fatigue is shown in the illustration. A piece about 20 in. long, is cut from an old automobile tube. It should include the valve. The ends of the section are stuck together with rubber ce- ment and allow- ed to dry thor- = oughly, after cml ied - which they are tested for leaks. If it is found air- tight the tube is bent into a rough circle and the flapscementedto each other, forme ing whathas been called a “‘life pre- server” from its WD) resemblance to that apparatus. When inflated to fifteen or twenty pounds pres- sure, this ring makes a comfortable cushion.—D. A. HAMPSON. CLOTH TO HOLD INNER TUBE IN PLACE It makes life easier for the workman ee +

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blic 10d vas op ~s 5 a i | “September, 1919

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Utilizing a Second-Hand Magneto T is sometimes necessary to adapt to one type of gas engine a high- tension magneto intended for another type. This is apt to be a rather puzzling job, especially in the case of motor-boats, in which a great variety of engines are in use. The following table shows at a glance the proper gear ratio and dis- tributor connections for all cases that can be handled without alteration of the magneto itself. The gear ratio referred to is that of the crankshaft to the main shaft of the magneto. For example: if the ratio given is 2, then the magneto armature must make two revolutions for each revolution of the engine. The leads, shown in the diagram as rising from the distributor, go to the cylinders in their proper firing order. All .others must be grounded, to protect the magneto from excessive voltage. 1. FOUR-CYLINDER MAGNETO 4 distributor terminals 2 sparks per revolution No. of cylinders...... S47 &@ F.1 Berek cycle... ....... £424 4 2 4 Ratio { revolutions of magneto for . each ahem of crankshaft 5 Ue Ce be Distribsitor connections: BUS PSS “For engines with crankshaft opposite; usual 2-cylinder, 4-cycle type. fFor engines with cranks together (0°); also double opposed engines with cranks op- posite. 2. SIX-CYLINDER MAGNETO (6 terminals, 2 sparks per revolution) No. of cylinders... . . eB: a oe 2 or 4 cycle. .:..:..... 4-422 4 2 Bs ss eaeccnivs ss 15 1.5 1.5 1.5 1.5 Distributor connections:

Of course the system works both ways. It is often possible to adapt a magneto to an engine having more cylinders than the one for which it was intended by purchasing comparatively inexpensive parts—a new distributor cover, and, if the magneto gives but one spark per revolution, new breaker cams. However, it is almost out of the question to shift over from the six cylinder class to the four, and vice versa. - If the engine is too heavy to start'on the Magneto, as often: happens. in motor boat work, the addition’ of a simple ” ‘vibrator. and resistance,. con; nected, as shown in the first, “sketeh, makes it possible to start on batteries. “YANKEE” Tool Book showing YANKEE” Tools in action; illustrating Bench, Breast, Chain and Hand Drills, Ratchet Tap Wrenches, Remove- able Vises, Ratchet, Spiral Ratchet and Plain Screw- drivers, all having unusual features of advantage over f i iittim k

(Puiu NORTH BROS. MFG. CO. PHILADELPHIA

N\ r

“This Feed Saves Drill Points” It doesn’t take long for the “YANKEE” Bench Drill to earn itself by saving the breakage of drill points. The Automatic Friction and Ratchet Feed, indi- cated in the illustration, regulates the feed ‘as nobody could ever do by hand. In operation, the drill is run down to contact with the work by the Friction Feed. . The moment the drill begins to cut, the feed auto- matically changes to Ratchet movement, giving an absolute uniform pressure through the cut. Evendrill points as smallas No. 45 arenot broken - in use, regardless of the inexperience of the op- erator, because it is impossible to over-feed “YAN KEE Bench Drill Two speeds, 3-jaw chuck, holds drills p to % in. “Height, 28 in. Price, (Philadelphia) idle /piv odiessis sheen $21. 0Oo ge Fa a om up ex y% eight, 1834 in. rice, CARMAN «<< -xancee ceaue $12. 5° “YANKEE” VISE, No. 990 Accurately machined sides, ends and bottoms, for holding work on Bench Drills and other machine tools. Swivel-jaw for taper work; groove for — rounds. Base, 6 in. jong: 25 in. wide. $3. 10 PO. 65.6 Zaina tes 8 eee Your Dealer Can Supply You.

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Types for all purposes and for all Languages Spacing to sult size of type Perfect alignment Guiomatiec Sybe Impression All on one MULTIPLEX However many Nations, are eventually recognized, and taken into a League, there is a typewriter that can write the language of ‘each and every one, the— MULTIPLEX HAMMOND Standard ‘‘Writing Machine” —the typewriter upon which the first covenants for a League of ny were drawn up—the typewriter that the Press of the Nation refers to as ‘‘President Wilson's Closest Confidant.’’ 8 rhe Multiplex is un-like any other typewriter —there are over 365 different type-sets, in- cluding all languages to select from. Note the six styles =ore above This ine “needs no interpreter—it can write bo and every Nation’s own language, its covenants and correspondence. Yet, with all 7 Venere of mechanism, its instant change es and type-styles, it is most simple of pete on, and does perfect work automatically. Making Your Writing Talk! With the Multiplex you can put emphasis when and where you want it—literally making your writing talk. That’s why lecturers, lawyers, clergymen, authors, and business men who realize the value of persontlity in writing, use the Multiplex. fact, this versatile machine often makes a man’s writing more forceful than his speech. Send for FREE PAMPHLET **How President Wilson Frightened the Lords at a agg and other descriptive literature explaining the unique features oi the Multiplex. Write your name, address and occu- pation.on the margin of this page NOW and mail the margin to— THE HAMMOND TYPEWRITER CO. 639 East 69th Street New York City Also—an Aluminum PORTABLE Model For Traveling—for Home. Weighs about II Ibs. Full capacity. Ask for special folder. Build Your Own PHONOGRAPH It's Easy With Our Hep w hours interesting ee. many dollars and gives you machine exactly to suit ae ideals. We furnis case material, blue Ine. prints and ‘full instructions. — J : focerd. You ~ hi make fine fine pro’ it buildin onographs for your friends. e Write Today for Our Free Blue Print Offer Agents wanted for our ready built phonographs Choraleon Phonograph Co. 609 Monger Bidg,, Elkhart, Ind. The ONLY pe?féct, non-leakab! ‘ pencils at moderate lenkable ink These vibrators are sold by several magneto firms. In an emergency they can be improvised. Last year I used the vibrator of a broken-down spark coil in this way for more than a month, and, as an experiment, an electric bell vibrator for a short time. Of course they were rather unsatis- MAGNETO GROUND TERMINAL f STOP TWO-WAY. SWITCH VIBRATOR AND RESISTANCE f START BATTERY HHH RUN = “—~cGrounD—” ~*~ When heavy engines are to be started the contrivance depicted above simplifies it factory, particularly the latter; but without them we could hardly start up at all. If you improvise such a system, be very careful to have enough resistance in the circuit to protect the magneto from the full short circuit current of the battery. The best arrangement of all for starting a heavy engine is probably the impulse starter so commonly used upon tractors. With such an outfit you are independent of battery worry and expense. Such starters can be had at moderate cost, or even home- made, if one has the necessary fa- cilities. JOHN A. PRIOR. Make a Weeder from an Old Wagon Spring OW is the time to weed out those unsightly spots on your lawn and get it in condition for fine velvety grass to grow up next year. The usual tool for cutting weeds is an old case knife, but the tip of a broken wagon or automobile spring is far better, as it will stand more prying when removing the weed’s root. The va ul mi incl Ts Ce i v [lw a A \ Grind down the tip of an old wagon spring into a lawn weeder length of the blade from the handle to - ‘the: cutting edge is 6 in., the. spur more. The cutting edge should not be squared across, but slant inward at Se her) tale ae “han Xe, gle shown, so that in press- Popular Science M onthly q comme =~ Easy Monthly Payments 17 Cents a Day Pays For the mellow-toned Symphonic Piano. Several beautiful models in genuine Mahogany, Oak and Walnut. Guaranteed 25 years. Sold the celebrated Larkin Factory- to-Family way. Many music Lovers have saved $100 to $200 in buying Symphonics. Our plan permits 30 dzys’ trial in your home. Four years’ time with: out interest. Convenient monthly payments. Ask today for FREE Catalog illustrating and describing Symphonics. Show Symphonic Pianos Also Player Pianos and Grands instruments in actual colors. Please state whether interested in the Symphonic Piano, the Symphonic Plaver Piano (which any. one can play) or the Syinphonic Baby GRAND. Write now for your Catalog. Latkhitt Coe Desk PPSM-919, Buffalo, N. Y. Rider or Agents Wanted Sracranere to and exe St pg e”” comple’ with electric Aight , a ice of 44 other styfes, colors and sizes in the “Ranger”? LE - 4S aes EASY PAYM fdesired at a smal) sais: qver our | Spee wee waelesole cash CYCLE COMPANY Vi EAD © Dept.$/09 Chicago Write Secret Letters With Invisible Ink Pour seemingly plain water into three glasses sa have * turn red in vlad fh white in another ake blue in the thir our Own magic writing paper, and blue ink or “y rite with plan’ water and have the writior turn blue. auspriee 7 and Ln he ur friends with these and more mysters us and am sing C cael ees if you have’ “CHEMCRAF iature chemical outfit é for your ye Tight now; it’s the greatest fun-maker you ever had. at ‘once and get a Free copy of ‘ar Chemcraft Chemist, ”* an a magazine or boys. amateur Chemist \ Catalogue and Hand Book containing much valuable informa- tion for Boy Chemists and listing many useful chemicals and apparatus sent me ‘Si POSTPAID Raise Belgian Hares for us. Wonderful profits easily made: at home. We furnish stock and pay you $7 a pair and express charges and buy all you raise. Also cavies and squabs. Illustrated catalog and contract Free MCRAFT” a Outfits, $1.50, $3.00 and $5. 00. THE PORTER CHEMICAL CO. Hagerstown, Md. 7+) 329 West 48th St. running out about 144 to 134 in.! UNITED FOOD & FUR ASSOCIATION Desk 4 New York ="| YOU NEED A RELIABLE STEFFEY MOTOR ATTACHED TO YOUR BICYCLE. Converts it into a practical, high grade EA, Motor-cycle that will cost ~ you less to operate than a 2 heavy machine. Write today | and secure es low factory prices. Send stamp. STEFFEY MFG. CO. Dept. S. 5025 Brown St., Philadelphia, Pa. LEARN TELEGRAPHY ot nome in ~ gee possible gue, Morse MNIGRAPH AUTO. MATIC. “TRANSMITTER, " eumemen ert operator wo wan Combes or or Buzzer seers you Rs S. Govt. 6 woul: chepted by by OMNIGRAPH MFG. CO. 39-H Cortlandt St., New York

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30 Days’ Tria > ays itiful models years. Sold nusic Lovers s’ time with. y for FREE S ds nterested in (which any. ite now for alo, N.Y, September, 1919 the handle, but if the knife is made Repairing the Wires on an ing it forward, the roots may be drawn toward the spur, rather than outward. The cutting edge should be sharpened from both sides, like. a knife, rather than from one side like a chisel. Woodea side-pieces riveted to the shank form from heavier material it would be bet- ter to draw the material down to a square or round shank, and insert the handle with ferrule. This improvised lawn weeder can also be used in the garden, for it is in- valuable for loosening the soil about growing vegetables and for transplant- ing delicate shoots, ete. Oil will keep it from rusting.—C. A. PEASE. Electric Iron FEW days ago the switch on our electric iron was broken. It was taken to an electrical shop, but the dealer wanted $2.50 for a new switch, SWITCn CASE A AFIBRE CASE The iron as it originally appeared, and details of the old switch FIG.2 which was almost what the iron was worth. The old switch was taken home and the connection repaired in the following manner, at the mere cost of a few minutes’ labor. In Fig. 1 is shown the switch and iron complete. The switch is held on the handle of the iron by a hook and also slips down on two prongs which connect with the heat- ing element. The switch and fiber case pull off and are composed of two parts—the case, which protects the switch, and the switch proper, which is mounted on the back of the case. See Fig. 2. The casing was taken apart, and the whole of the switch, including the binding - posts, was re- moved, with the excep- tion of the two metal terminals B and C and the protecting spring D on the inside. The cord was then con- nected direct to B and C as shown in Fig. 3, and | the other half of the cas- FIG.4 ing was put in place The complete and fastened. See Fig. 4, connection The casing was slipped back on the ‘iron and the current turned on and off The wires connected to the terminals at the lighting fixture instead of the | . fb es Oe Just total in dollars and cents what you have spent this year for pencils, old style pens andink. Do not forget to figure for pencils,the portion wasted in sharpening, and for ink the amount lost in evaporation. To be conservative, allow at least half in each case. Compare this unnecessary extravagance with the economy and vastly greater efficiency of Sold at $2.50 and up Thousands of Waterman’s Ideal Fountain Pens haverecords of over twenty years of continuous unfailing service. They waste nothing They make permanent records y are always ready They are unequalled in convenience Indispensable ‘or the bookkeepers, authors, doctors, lawyers, salesmen, students, stenographers and social correspondence. Three types, Regular, Safety and Self-Filling Sold by Best Dealers Use Waterman’s Ideal Ink Best for Fountain Pens and seneral use as well L. E. Waterman Company, 191 Broadway, New York BOSTON CHICAGO SAN FRANCISCO IN ew i. Tr umpet Plays in C, Bb, and A This Superb Blorite ‘Triple Tone Model Trumpet’’ cannot be equalled for indoor and outdoor work. Just what mvsicians have long wanted. Prove to yourself, in your own home, its superior tone and qua ity. you have tried the Triple-Tone Blorite. Sent on Trial Send today for illustrated catalog, just Easy Ter WAS cut, of Blorite cornets, trumpets, trom- bones, fites, bugles, drums, etc. SPECIAL LOW INTRODUCTORY PRICES Blorite Instrument House, napersitic, in. Don’t buy acornet or trumpet until USE HB BALL BEARING eR ey ese Cemy Copue) e Save on Power Bills —-Get Better Power HB Ball-Bearing Motors supply better power than gas engine or steam engine, and cost less to operate, Amply designed for hard service trouble proof, absolutely reliable. Ideal for fac- tory. garage or machine shop. Best service at lowest cost. $20.00 Brings You a 2 HB Motor. e on Easy erms. es 1 to 1S h.p. Choose to Suit Your Needs. In planning your installation, write i cepartment. Get their reru at least cost. our letterhead and mail TODAY for full information. Ask also abou! ittery Chargers, Genera- tors, etc. HOBART BROTHERS COMPANY Box $93 Troy, Ohio Successful Mamufacturers Since 1898 CLEARTONE . PHONOGRAPHS — $4.00 to $200.00 Retail ' Our Sundry Dept. offers Needles 39c. per thousand, in lots of 500,000. Motors $1.35 to $14.75 each. Tone Arms and Reproducers $1.30 to $5.75 per set, Main Springs 20c. to 90c, each. Records, Needles, Sape phire Points and Parts at reasonable prices. Write for our 84 page catalogue, the only one of its kind in America, illustrating 33 different styles of Talking Machines and over 500 different Phonoe graphic Parts, LUCKY 13 PHONOGRAPH COMPANY Export Dept. 46G, E. 12th St.,.N.Y., U.S.A. DIRECT FROM FACTORY TO YOU OUR NEW CATALOG WITH 600 OF THE LATEST UP-TO-DATE DESIGNS FREE. Cc. K. GROUSE CO. 12 Bruce Ave.. North Attleboro, Mass. >| A095 PINS-RINGS To Have Friends Be One. Florists’ Telegraph Delivery Service. iron:— ALBERT E.° JONEs. Remember the. birthdays and anniversaries. of. your : friends , -With flowers. Your. local. florist within a ‘few. hours, as. deliver fresh flowers in any city or town in the. United States or.Canada through the They will serve you.

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new ideas, You tee fem — Auto> Wheel Coaster | ite Sawn the 4 BOADSTER

la The Circus Parade | jim, the Club Captain, is a great one for ‘When the circus hit town last week, he said the cAuto-Wheel Coaster Club. “ought to march in that parade.” So we all took our cAuto- Wheels down to Leg en and when the march started ed in. We hitched on to the biggest Dame in the show and followed along. cleph didn't have to decorate those <Auto- Wheels. They’ - ieee to a —_ And they ran along just as smooth as au should have heard the crowd cheer

‘Adventures of the aster Club when we passed. Biggest Hit in the Whole Parade,” the folks said. And after it was over five fellows came up and wanted to know where they could get cAuto- Wheels. Jim sent them to the. local . dealer, and they are going to join the Club. Jim has’ sent to The. Buffalo Sled Co., for FREE Club Caps for them, like ours. BOYS:—DO YOU WANT WAGONS LIKE THESE f The Auto - Wheel aA omg is a speedy. The Auto-Wheel Con- —_ ener is two yous one—can be changed from Coaster to Roadster in a second. Send us three dealers’ names, oe which one handles the Pros Pelt Pennant and Booklet. The Buffalo Sled Co., 157 Schenck Street,

N. TONAWANDA, N. Y.

(In Canada: Preston, Ont.)

Fly a lane right awa

Cor. Houston and g Build and a - NC=-4 This new “IDEAL” Model Aeroplane is a dandy—the ‘celebrated Naval-Curtiss Seaplane, first to cross the | Atlantic Ocean—a strictly American ‘plane every Amer- ican boy will want to build. gs a true, scale-model To of the real NC-4. anteed to rise from fight u cg its own power. . Acccurate e Plans, including Buil Instructions, sand build this wonderful D Plan andlnstructions or Baling 474 foot Model NC-4 50c Other Plans and Instructio following prices, all sent Fs DE HAVILLAND BATTLE PLANE..... 35c Curtiss Military Tractor.............. 25¢ Biesbot Monoplane <.. 2 .i:. 0. ccc ees 25c Nieuport Monoplane ...........+.-..- 25c Taubé.Monoplane’..............+... 25¢ Peolt, Racer “IDEAL” Model Aeroplane ConstructionOutfits contain- ing all parts and materials needed to build these Model Aeroplanes are sold by Leading Toy, Sporting Goods and Dépariment Stores. . Ask for them at your store. ** IDEAL’’ Model Aeroplane Catalog, _..48 pages. IDEAL AEROPLANE & SUPPLY COMPANY Model of the 4% feet across the planes* the water and make & perfect Get _a set of “IDEAL” and Flying odel Aero- 5c postpaid. stablished in 1911 Wooster Sts., New York City

your vacation.

MAXIM SILENCER co. - «91 Homestead Ave., Hartford, Conn. NO ‘SELESS TARGET PRACTICE Fit your .22 with a Micim Silencer ani get no ae be fun this simmer practicing in your baekyard SiN NCI ER = ABETTER MARKSMAN |. tt eiminates reco! and ll nolo FREE Direct trom Denier or Fax. COOK tary, s8.0, Write for Free Book SEND “FOR Ti

Popular Science M. onthly The New Fad—Metal Flowers ETAL roses—in fact, any flowers made of metal—require considerable skill. and patience in making, but the work is not so difficult if one under- stands the “‘trick’”’ in the method. In fact, any fairly ingenious mechanic can make metal roses with but a few tools once he grasps the idea. The flowers may be made to look as natural and beautiful as nature’s product, and they never fade or wither. You will need a quantity of round iron rods 3/16 in. in diameter, a sheet lt fa STEM

FIG.1.- LEAF The rod is now hammered into the form of stems and rose leaves of 1/82 in. black wrought sheet-iron, a hammer, a chisel, a pair of snips, tongs, and an anvil, a blacksmith’s forge, or, better, a welding-torch The Leaf Cut off a piece of the iron rod, five inches long or thereabouts; heat one a

€1G.3.-SEPALS The sepals are marked out in a chalked circle, cut and hammered thin, then bent into shape end of it bright red and hammer it to a long point like that of a pencil; heat the other end and make it slightly wedge shape. Now reheat the pointed end and flatten it; hammer it out until it is wide and thin, when it should have the general shape of a rosc-leaf. Heat again to a dull red, and mark the veins with the chisel; also cut the little notches around the edges. Then bend it to the shape of a rose-leai. See Fig. 1. Make several leaves and weld them together. The Stem and Sepals The stem is made next, from a piece of the iron rod about the dimensions of the leaf piece. Wedge one end of this and draw out the other end to a smaller diameter, as shown in Fig. 2. Cut out a circular disk of the sheet- metal with the snips, and mark off six sections with chalk. Make the disk about two and a half inches in dia- meter. Now drill a hole through the exact center large enough to fit the small end of thestem. Mark it off into sepals and trim them out. Now heat the sepals one at a time and hammer them thin with the ball peen of the hammer and bend them into shape. Petals 1a To siaké the petals, cut thitee disks three inches in diameter from the sheet-iron. Punch a hole in the center 108 By David Baxter of the petal sections the same as in the sepalsections. Cut on the dotted line and trim the petals. Heat each petal in turn to a bright red and hammer very thin. Keep hot while ham- mering to prevent cracks. Use snips to trim the ragged edges and to round out the petals. After the petal sec- tions are hammered and trimmed, heat each one and mold it into a cup shape with the ball peen of the hammer. Cup all the sections so that they will fit one within the other. (Fig. 4 il. lustrates all this procedure.) Articulating the Parts Now to put the rose together. Slip the sepal section onto the shank of the stem piece. Solder it in place; or, better still, weld it in place. Bend the edges up to the proper shape to fit the bottom petal section, which is added next. Squeeze the first petal section within the sepal section, and fasten with a drop of solder. Then squeeze in another petal section, and solder it. Draw each section inward more or less, according to whether it is desired to make a full-blown rose or a bud. Have one edge of each petal fit on the inside of the others in rota- tion around the rose. Follow the second petal section with the third and last one, lapping the petals in the same manner as On the others. Melt a quantity of solder over the end of the stem to hold the petal sections firmly

FIG.4.- PETALS The petals must be kept at red heat when they are being pounded and molded into shape in place. (Fig. 5 shows this part of the work.) The metal, being thin and pliant, can be readily shaped with a pair of pliers. If an acetylene welding plant is at hand the welding may be substituted ‘ha F1IG.5.-THE ROSE The whole process is interesting and the resulting effect is really artistic

for the soldering, and it makes a better job. The welded rose must be put together hot . The last-step is to weld or solder the leaves to the stem. This should be done with particular care, as:all of the work will be in sight. The foregoing idea may be enlarged and varied; for instance, a number of roses may be welded to a ring of iron to ' form_a wreath. The metal roses are pleasing enough in metal colors, but may be enameled in different colors, especially if a wreath is made. Copper may be employed instead of sheet-iron.

yg

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ns che ine tal ler ips nd ec- at pe er. vill al a- he rd he lt of in th at September, 191 9 i 4 Whee ye zt A ° BHS we % ae i oes) Tome {> Wide 4] ee -Draf Smant.. L. TTT eM SNe me onernntg rameters pe aeniemeee susan “aes 8B & 5 @ ware NLD SRA corayrity DESIG RNP Want? OT one of these jobs is beyond your reach. You can have any one you want. The big pay that goes with it is yours, too. A little ambition and some training that you give yourself at home is all you need. You don’t have to serve an apprenticeship. You don’t have to go to school. American Technical . Society Home Study Books and a little spare time will quickly fit you to hold any kind of job. If you haven’t the necessary “know how” to put you in the big pay class, make up your mind to get it right now. Pick out the job you want and send the coupon for the books that will fit you to hold it. Some of the greatest experts in the world prepared these books just for you —to help you get ahead. They are written in plain, everyday, good old U.S. language, just like you andI talk. No big technical terms—no trouble to under- stand them. Hundreds of pictures and diagrams in each set help to make difficult things as simple as A. B.C. Examine Any Books Free i Carpentry and Contracting, 5 volumes, Steam and Gas Engineering, 7 volumes, i 2138 pages, 1000 pictures, Was $25.00. Now...$17.80 3300 pages, 2500 pictures. Was $35.00. Now...821.80 4 Civil Engineering, 9 volumes, 3900 pages, Law and Practice (with reading comes) 13 i 3000 pictures, Was 845.00. Now.......ccsscssssee 29,80 um 6000 pages, illustrated. Was $72.00. Now 39.80 i Fire Prevention and Insurance. 4 vol- elephony and Telegraphy, 4 volumes, i umes, 1500 pages, 600 pictures. Was 820.00. Now 15.80 1728 pages, 2000 pictures. Was $20.00. Now... 12.80 Sanitation, Heating anti Ventilating, 4 Electrical, Engineering, 8,yolumes, 300, “Wolume, Wt page, io pictures Wassai in 3.80 Automobile Engineering, 6 volumes, 2600 pages, 2000 pictures. Was $30.00. Now......... nso Pugetpent Accomm. cep, Memes Machine Shop Practice, 6 volumes, 2300 Drawing, 4 volumes, 1578 pages, 1000 pictures, payes, 2000 pictures, Was $30.00. Now......... 19.80 blueprints, etc, Was $20.00. NoOW......cccssssssee 14.80 5 The coupon alone, properly filled Mo t Send out a books pe select by Only 50c express collect. No money to pay o mn e Y in advance and no diiautun to Pte a We e ik Use the books as you please for a week and send them back at our expense if you wantto. If you decide to keep the books to help you make more money like thousands of other men have done, send us only $2.00 each month, This is only 50 cents a week, Those who send the coupon promptly will Extra Special be enrolled as a consulting member of our Society for one year. This gives you FREE OFFER the privilege of consulting our engin- ‘ eers and experts on any problem con- nected with your work—Free of any charge. Go after one of these big jobs now. This is the time. Trained men were never more needed than they are today. This coupon is your start on the road to real success. MAIL IT NOW. American Technical Society Department X206 Chicago oy [ ” Office~Manage

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Popular Science Monthly Dont Let Ailments An Emergency Magneto Drag You Down — Music Lessons . ANY a man of first FOUND myself stranded on one - UNDER MASTER ACHERS rate ability, fitted occasion with complete ignition mentally to make a mark in life, is knocked | | failure, and investigation revealed the | {0H At H ome erie pterctinste ‘| | fact that the high-tension brush of my | |\sEammsfilismtheaam Y —. ments that rob him of his | | magneto was fractured. The nearest | A Complete Conservatory Course him sickly and weak and town being about five miles meas By Mail rest’ Zrnerigan and Forope mtctene “Don't let chronic ail- eee that before starting to pus you. Lessons a marvel of simplicity and pnd we dort ments down youl A Any Instrument or Voice Writ: telling Py Ps > . us course you sound mind in a sound are interested in—Piano, Harmony, Voice, Public School body is the ONLY com- Music, Violin, Cornet, Mandolin, Guitar, Banjo, or Reed ody i I Organ—and we will send our FREE CATALOG covering bination es enna Fn all aeieementel and rocal coamees, ana BOW no the battle of life. fe) RY mancan do things that 5986 Siegel-Myers Bldg. Chicago, IIlinoig COUNT, while constipa- tion, dyspep;ia, indiges- tion, biliousness, nervous H B BATTE a4 C | ARG ING B doves ais any other of PAYS B if re PROFITS back and ceeamay "trap: a dozen disorders have got him doin into the A temporary motorcycle magneto repair was $100 to $200 Clear EXTRA PROFIT Each Month ging i 4 junk pile of weak, sickly, : . : . New Low Price on this HB 500 Watt Charger wornout, worthless men. accomplished with a saad of lead pencil Recharges 1 to: ¥6-velt botterton at once for 10¢ to 15c each; CLEAN HOUSE! a big, profitable business in battery ebarwing. beets aha Clean up your bodily or- | | the motorcycle in I would do my best en sm and give yours! ° ° Ehance. «et the deadly to make some sort of repair and risk Small Cash Payment Puts This poison of constipation out tipa nett : ‘ of your system. bree your riding the machine with the fragment HB Outfit in Your Shop Balance on easy monthlyterms. Profits sand and grit that is clogging of the old brush still in the magneto. easily carry payments. No burnouts, no it and keeping it from run- expensive renewals—steady, dependable q nt have pervice sith BIG PROFITS, Absolute stroncronr = MDE Tent. Youcanthave || —_ The absence of a file from my tool | ff Hen Back charasres, feat out The Perfect Man that condition you can't kit made it impossible to shape any tremation. Sion assome tur tethir’ of sre p . HOBART BROTHERS COMPANY children happy: you can't, even become the father of | | DleCe of steel or brass satisfactorily, Box S91 Troy, Ohio @ rey gardener wed ee te siemaer. Get fd even if I had been willing to risk Successful Manufacturers since 1893 of the CAUSE of your ailments, and the troubles pa 4 7 themselves will quickly disappear. scoring up the slip-ring. It suddenly You can do it, if you will stop—think—appreciate the os ee is 7 toboggan: you are on, and take steps at once to remedy | | Occurred to me that the “lead” in a W fayette the conditions that are making a sickly failure of your en > LD YOU UP pencil is only another form of carbon, D Bos BLACK:BEAUTY "LL HELP BUI and as such is, of course, a conductor. ¢ world’s most ma There's only one safe, sure way out of your troubles— ° ° cycte—Black Beauty! Built in Nature's way. I'll show it to you. Ili tell you how Further, the wood surrounding it | ourown bigtactory,of the finest materials you can free yourself from the handicaps that are im- t re obtainable and with 18 Exclusive Fea- ling all your chances of hap; iness and success in would do no harm to the slip-ring. I ures. Yet costsno more than an ordinary ife. I'll teach you how to develop your abby muscles : : . Sewer wheel—we ship dircct at wholesale price. and put real meat on them; how to strengthen your had very little difficulty in whittling | No miadiemen’s profits! Absolute5-yr. heart, lungs, stomach and every other vital organ how * ° 1: e guarantee and f-ee accident insurance. to become well and strong and red-blooded and vigor- a piece of pencil until it was a fairly WRITE TODAY for Catalog (in col- ous—how to oe back your manhood and the ability to . ors) FREE. 20 Styles. Tell us model you DO THINGS THAT COUNT. good fit in the carbon brush-holder. want. Send no money—we ship at our I have spent a lifetime studying the causes of mental : own risk. No waiting. Keep wheel or return at our ex- and physical deterioration and learning Nature’s meth- Of this, I cut off a length equal to that pense. If accepted pay small deposit, then §1a week. |] ods of resto ing vigor and vitality to weak, ailing men ° ° Get our factory prices. Lowestin the I have built up and given renewed hope and enthusiasm of the old brush, and stripped all the Sundries country. TIRES, lamps, horns, etc. and the buoyancy of youth to thousands of discouraged ° ff h ] f v3 —everything for cyclists. Free Sundries Catalog. men who felt that they were down and out for good covering off the lead for about \% in. HAVERFORD CYCLE CO., Dep.G71Philadelphia makes no di erence what your present condition is; at one extremity. I then altered one 4 A Pe ‘q ~~ CLASS PINS or early dissipations and excesses of your own. 1, wtll end of the spring so that a few turns for a few months —I GUARANTEE IT. were wrapped round the projection | = CLASS OR SOCIETY—CATALOG FREE STRONGFORTISM thus produced. The other end of ae eeepc wet ought 10 be lived—wnich always means getung tne | | this improvised brush was smoothed | YY} ures, Enameled Red-White- cure. levery reputable physician and purgeon in the off by rubbing it on the sandpaper Blue, Silver plate 20c ea. “Nee $2.00 doz. Sterling silver, 35c ea., $3.50 doz. world depends on the wonderful restorative powers of BASTIAN BROS. CO. 770 Bastian Bldg., Rochester, N. Y. Nature as his greatest Ally. Every.one of them will on a match-box, and the job was tell you to avoid advertised patent medicine ‘‘cure-alls d Sree Gereratse: tae eee | | One . eee: ow . but they never pu’ ealth and strength and vim and. vigor into men. “ My only doubt was as to whether Tri State Colle @ of En Ineerin There s no druggist s dope of any kind in my system the small rod of carbon bein im- of Strongfortism. Theres no complicated gymnastic ’ g Mak 7 Civil, Electrical, Mech ical apparatus to buy. There's no rigid routine of foolish bedded in the wood d flush with it Make you a Ulivi, Electrical, Mechanical or fatiguing physical e ercises in the Strongfort way. e € wood and Hush with It | Chemical Engineer in two years, or 96 weeks. Nuture doesn't.do things that way. 4 . . ° > SEND FOR MY FREE BOOK at the end, would not make sufficiently | No entrance examination. H. S. education You will find all about this natural way of building good contact to collect the current. | not required. Total expense per year of 48 yourself up _iD 4j, Promotion and Conservation of This would have been the case, prob- weeks, tuition, board, lodging, heat and light practice it in the privacy of your own home, without ably had I been dealing with low- $220, Same price for Commercial courses. terfering in any way with your present occupation. ’ 12 Pine Street. ANGOLA, INDIANA The result of my life's study is in that book. ou voltage current ; Weoundiag Bese rene a eu aae™ ate ing th y aw od IT hed nbag gp — me ege below pet On fitting the emergency brush I seni me w hree i : Postage and t Wi forward you 2 copy Gr backing and was delighted to = = the J ecial letter on the points in which ‘you are particu- engine ran quit Ww ; a larly interested. gl quite as well as usual, and Begin Today—Write for My FREE BOOK LIONEL STRON I firmly believe that I need never Tcan make a good penman of you at home during GFORT ] R : are time. Write for my «et a cor “*How to Physical and Health Specialist have replaced this extemporized brush wong yd gill KE Ay jm by the Tamblyn System. Your name will be ele- - >| gantly written on a card if you enclose stamp to pay postage, FREE BOOK— Write for it Today. F. W. Tamblyn. 4°7 Pidce Blde.. Kansas City. U. S. A. 1055 Strongfort Institute, NEWARK, N. J. with a new one.—G. F. CoLLINs. aaeaCUT OUT AND MAIL THIS COUPONs een Mr. Lionel Strongfort, Newark, N. J. dD Strongfort —Pi i e a e & “PROMOTION AND CONSERVATION OF HEALTH. An Electric Photo-P rinting -6 STRENGTH AND. MENTAL ENERGY,” for postage C , e expenses. | T have muried cx) beore te wpject ts © | Machine to Suit Everybody Cc am in es ° (1055) . aOR A STR I SAT NAR RESERIRIE REDE SIO kp tare a HIS machine is suitable for the Ifs Gause and Aire °° ns Obesity : Sor ; 7 professional because it makes for You can be quickly cured if you stammer. Send 10 cents, coin . «Headache Disorders . Skin Disorders greater production in less time and tt tells par Tuas che tenes te: + pBulamens - Constipation ee Despondeney : ; payee ron 20 oa a BENJAMIN N. BOGUE * . weness ee U . . hambare rp iver Sag rrosies™ with least exertion; it is a good thing &. ogue Bidg Indianapolis, Indiana_ gy Rena ‘* ker sme feet: | for the amateur on account of its simple ‘Deformity i__ -.o- and inexpensive construction, and pad img sand . Bad Habits Development because of the ease with which a good: |- ner timited possibilities | AME cece ecewearerersseeseeeeessssessessrenes ° ma ® men with creative ideas. O AGE........ OCCUPATION ............0+ be dinin ds cca “ores y he sbtained. . ork intensely interesting. peo! An ordinary’ wooden box will do as ae iw Aid STATE, long as it. is large enough to take from Bes usys Tikeciels' 4to6 100-watt lamps. 110 ee Bice onlaaw

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September, 1919 -The box is shown at A, in the bot- tom of which are fastened the lamps B. These are covered with a ground glass C and another ground glass, shown at D, should be placed about 4in. above C. This will greatly help to diffuse the light. At E a piece of plain glass (window glass will do) is shown, which is held in place by the frame F. In this an opening is cut a little larger than the largest plate or film you expect to print from. The top frame H can be made the same size as frame F. An arm I is hinged at K. At Laspring is put between arm ~ I and frame H. The pressure block is secured to arm J in such a position that it will enter the opening in the upper frame when the arm is Jowered. The method of fastening the pressure board to the arm is more clearly shown in the lower part of the illustration. A flat spring N is secured to the arm, and to this, in turn, is fastened the board by means of wood screws going through the slots P in spring N. These slots must be provided in order to allow the stretching of the spring when it is compressed. At Q is shown a block, on the top of which an ordinary push-button R is fastened. This is connected with the lamps, so that when the button is pressed down all the lamps will light up. A pin S , 1%" x2" RESSURE - SQ az PHOTO SIDE HOLES TO FASTEN SLOT FOR SCREW ) we. ai y PRESSURE BLOCK FELT Eliminating chance from printing photo- graphs, this machine makes excellent prints SPRING BRASS BENT MOUNTS is provided on. arm JI, just opposite the push button, and it must be long enough so that when the arm is in its lowest position the button is pushed in to close the circuit. The printing is now done in the fol- lowing manner: Place your plate or film on top of the plain glass E inside of the opening G, put che paper on top of the negative and press down arm I, holding it in position the required length of time to expose the print correctly, let go of the arm and the spring L will act. That Is, the arm will swing up high enough to allow you to insert a new- sheet, after removing the printed one. The wiring should allow one lamp to remain. lighted for use as a safe light behind a panel of orange ‘glass in one side of the box.—J. LIMBRUNNER:- wr at f ee ment and use. Tractor Busines AUTOMOBILE, Truck, and Tractor indus-' try now entering its greatest period of develop- 80,000 towns and rural communities without garages or repair shops of any kind. Inter- community Truck Hauling and Motor Mail Routes will require extensive maintenance and repair shop facilities. High cost of farm products making immense demand for farm tractors. Every man, 16 years of age and over, can qualify himself here to make big money as Motor Mechanic, or get into business for yourself and earn much more. We refer you to thousands of successful graduates. Learn Here in 6 to 8 Weeks Earn $100 to $400 a Month Immense additional equipment from Military Divis- ion of Rahe School. Same practical method as used to train thou- sands of Soldier Mechanics in 60-day courses. Only additional cost to take your training at the “ World’s Oldest and Greatest” Autoand Tractor School, is difference in carfare. % used. No‘‘extras” to buy. Only Life Scholarships issued. Plenty of opportunity to earn part living expenses while here. FREE NOW Write Today for 7-Day Trial Offer and 68-page Opportunity Book. State age and occupation, | Rahe Auto & Tractor School xisas'ciry, tao. No books -@ mrpeterat = i —— owe ee A AT SSN Don’t Wear a Truss Brooks’ Appliance, the modern scientific invention, the wonderful new discovery that relieves rupture, will be sent on trial. No obnoxious springs or ; pads. MR. C. E. BROOKS Brooks’ Rupture Appliance Has automatic Air Cushions. Binds and draws the broken parts together as you would a broken limb. No salves. No lies. Durable, cheap. Sent on trial to prove it. Protected by U. S. patents. Catalog and measure blanks mailed free. Send name and address today. BROOKS APPLIANCE CO., 255B State St., Marshall, Mich. — Send Your Name and We'll | Send i) Don't send a penny. Just send 3 a Lachnite moun’ 1 t| trial.’’ We will send it prepa‘d right to your home. | fing iG tall dave, te you, or ita ur ) ing for u ays. ° fr diamond, send it back. But if you decide to buy it | | send us $2.5C a month until $18.75 hae been paid. name now. Tell us which of the |} p| Write Today coid zou rincy ilustrated above vou wish [i ger size ( Qadies’ or men’s). i Harold Lachman Co., 12 N. Michigan Av.,Dept, 1.06 Chicago You a Lachnite name and say. *‘Send ted in a solid gold tee on 10 days’ -75 with the an and then wear the *] Be sure to se’ “DON’T SHOUT” “T hear you. I can hear now as well as anybody. ‘How?’ With THE MORLEY PHONE. I’ve a pair in my ears now, but they are invisible, I would not know that I had them, myself, only that I hear all right, “The Morley Phone for the DEAF is to the ears what glasses are to the eyes. Invisible, oe . = a le, weightless * and harmless. Anyone can adjust it.” Ov thousand sold. Write for booklet and simelie mee THE MORLEY CO., Dept. 797, Perry Bldg., Phila. FREE, canteen Akron Gas Lamps and jgnteene make best, cheapestliant. se gas- oline. Simple, dependable, durable, 4 Permitted by Insurance Companies. GIVES 400-CANDLE PowER Abundance of bright, clear, soft, Steady light--restfu lto eyes. Fully guaran i} a A spare time. Outfit free. Exclu- territory. Write for prices and REE catalog. Sold at wholesale in hi a_i AKRON GAS LAMP CO., 489 GAS BLDG. AKRON, OHIO ing, non-leakable, AGENTS tubs.’” Manning, 60,.00,’? And hun ALLOR SPare You can make $35.00 TIME to $100.00 gest thing in years. City conveniences without eD lumbing. Used in any room. Foe Sells on sight. Demonstrating tub furnished. Folds small, self-empty- Two sales daily means $60.00a week. Leggett, Ohio, ‘“Worked two hours, took two orders, profit $10 00." Hayhurst, Nebr., **Took 11 orders in 4% days—profit $55.00, ordered 12more 50.00." DeHut, Nebr., ‘‘Sold 12 sabe - three days—profit homes have no bath tubs, Experience and capital un: given totheright man, Get fell H. S. Robinson, Pres, 9 5031 Factories Buildin TOLEDO, OHIO a week, I want hustlers. money-makers, to work with me, to advertise, sell and appoint agents.Big- Guaran MAKE SALES EASILY Towa, ‘‘Sold 10 tubs in one day—profit is of others making » TWpercentof na ng Ip'an;”’ all Fars, particulars “specia| THE ROBINSON CABINET MFG. co. SHAW MFG. CO., 4 KS) Motorbicycle speedy, high at low cost. Chain drive. 90 fo 26 miles on a gallon of gasoline. Absolutely guaranteed. Write at once for full information about the Shaw Attachment—makes your old bike a motorcycle. dependable, easy running, wer motorbicycle Dept. 306 GALESBURG, KANSAS MERCHANT MARINE NEEDS THOUSANDS OF -OPERATORS and Telegraph Companies—Lake and Ocean Steamships. Salaries up to $250 a Mss and boys also needed for big land wireless stations—Aerial Mail Service—Railroad am ¢ month. Opportunity for promotions to Radio Engineer, Inspector, Mechanic or Electrician. Chance to see the world or locate at land station in America. COMPLETE COURSE BY MAIL IN TEN WEEKS Our students actually P A. Start studying NOW ass commercial 2xaminations in ten weeks or less n spar2 time at home We send you complete set \ > practicing instruments for receiving and sending messages while stud course. We help you secure position in commercial or government ae service. Representatives wanted to introauce our co ‘ Write today for Free Book and particulars. re ea ray KB, {= N NATIONAL RADIO INSTITUTE, Dept. 95. Washington, D. C.

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%) HE ship has three radio- sending sets, or really four if you count in the radio telephone unit which is auxiliary to one of the others,” said Lieutenant R. F. Durrant, Radio Officer of the dirigible airship R-34. “The first of these sets is a high-power transmitter. It operates on the continuous wave principle, two British Thompson-Houston 250-watt vacuum valves supplying the power. One alone of these valves may be used, or two may be operated in parallel. The valve’s filaments take 3.6 amperes each. High-tension potential applied varies from 1,000 to 3,000 volts. This comes from a small Newton generator mission. It will be much used.” Popular Science Monthly For the Radio Experimenter

How Radio Aided the R-34 By Lloyd E. Darling

ELOW the PoPpuLAR SCIENCE MONTHLY presents the only pictures of the dirigible R-34’s radio equipment ever.taken, either in this country or in England. From a histori- cal standpoint the apparatus is as important as any signalling equipment Columbus may have had on his momentous voyage to these shores—the crude flags, or whatever they did a little communicating with in those early days. Certainly, from the standpoint of momentous consequences, the two voyages themselves are on a par. Representatives of the POPULAR SCIENCE MONTHLY received special’ permission from Major G. H. Scott, commander of the airship, to go on board the control gondola,—the ship’s nerve center,—and make pictures. They were the only press representatives accorded such privileges while the airship was in this country, and but few others obtained so intimate a view of this highly technical part of the ship. Besides the radio pictures that follow, the one of the forward part of the con- trol cabin on page 81 of this issue was also obtained at this time. Lieutenant R. F. Durrant, the ship’s radio officer, was most kind in giving as extensive information as possible of the radio equipment in the limited time available. Since the radio cabin of the R-34 has a floor area only about as large as two flat-topped desks, the photog- rapher had to exercise considerable skill in getting good pictures. A photographer had tried it in England, but without result. To radio enthusiasts and technical men of this country who wonder what wireless equip- ment such a great ship as the R-34 had, this story will be of high interest.—EpDITorR.

a limousine, you couldn’t be exactly set, driven by a three-and-a-half horse- power motorcycle engine. The 1,000 to 3,000 variation in this set’s output voltage is secured by varying its field current with a guitable rheostat. With this outfit I can work 1,200 miles with- out trouble, and upon one or two occasions have reached as much as 1,500 miles. I am a firm believer in the future of continuous wave trans- at Cy i ‘ It had been difficult enough to get up into the R-34 during its stay in the United States. There were barriers enough to pass. For instance, the three rows of guards, arranged in concentric rings around the airship, with about a city block between rings. With some of these guards, even a pass from the command- er of the ship was “‘no good.”” Their breechless shot-guns were not nearly so fearsome as they looked, however, and certain which—the windows around the side were so plentiful and the equipment in general so neatly polished and comfortable. The control car of the R-34 is of the same general proportions as a small- sized street car, minus its wheels. But the roof is lower and the body has the streamline shape common to present-day aircraft. To get up into the car you grasp the handrail at the bottom just as the men in the picture on page 114 are grasping it, seizing as

amc remem art ‘| a word to the commander you go up such projections as you [ee | oftheguardbytheEnglish can get hold of, monkey-fashion. '| officer who took you in When airships are used generally for charge soon opened a way. transatlantic travel, the builders will Once inside the control have to devise different passenger- car you had afeeling of be- loading methods, particularly for ing within a greenhouse or portly ladies. - THREE-WAY AERIAL SWITCH : a, ‘ 4 i. * ns es 3 * ey , ; La 3 » = 4 S ) ens di PARALLEL <.

os CONDEN BERG: ihe

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The radio cabin’s right corner and rear. This view and the one at left overlap. Between the two you see most of three sides of the room. All the Atlantic talked here during the flight rete Left corner and rear wall of..the -R-34’s radio. ©: j~..-4 cabin. Note the smallness of the room and the compact arrangement of the radio apparatus

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Se ptember, 1919 Forward in the control car are the wheels and levers that control the ship’s rudder and the elevators (not passenger elevators, but the side fins on the ship’s body near the tail that regulate up-and-down motion in the air). The rudder and elevator control apparatus has the general appearance of similar machinery in an ocean-going vessel’s pilot-house. Here also, in the forward end of the car, are shelves and a little table for navigating appara- tusand maps. Meters and dials cover the walls. The control car is divided into two equal parts by a crosswise partition at the center. To the rear is an engine- room—one of four engine-rooms on the airship, the others being in special gondolas farther along the great gas- bag’s length. Immediately in front of the forward gondola’s center partition is the radio operator’s cabin. This is a little room about six feet long by four or five wide, with a narrow passageway on the out- side, which resembles the corridor in a compartment railway car. Of course the scale is much smaller but the work- manship on the woodwork and its neat finish remind one of a Pullman. Inside the radio cabin was Lieutenant R. F. Durrant, the ship’s radio officer. His explanations of the equipment under his charge were most satisfying. He continued: “The second set is a specially con- structed continuous wave transmitter using two British Thompson-Houston tubes rated at fifty watts. This unit usually works up to 500 miles. The voltage applied to the tubes is never more than 1,200. This comes from a small Newton auxiliary motor-genera- tor, taking 12 volts, 40 amperes on the input side, and delivering even 1,500 volts if wanted. The motor generator weighs but eleven pounds. “Used in conjunction with this second set is the wireless telephone unit. This will give clear speech up to eighty miles. I use it frequently. It is of especial value in landing, enabling us to be advised of ground barometric readings and temperatures with ease and promptness. This information is very vital in landing an airship on an even keel. There are twenty ballonets up in the hull of the ship, each filled with hydrogen. The lifting power of these varies markedly with changes in barometric pressure as well as tempera- tures. There are three tons of water up there also, and sometimes as much as 6,000 gallons of petrol (gasoline). So we have to know all about ground conditions before we begin to let out water and hydrogen and come down. A certain amount of hydrogen and water in the hull’s containers may keep us in equilibrium at a given height, but to come down the quantity of both has to’ be lessened, that we may land evenly and without a jar that would damage some of the under- parts of the ship. The radiotelephone is indeed handy in this connection. “The third radio set is a spark | 7 WLLL eg THE HEART OF THE WIRELESS ON THE NC ‘PLANES Also used on the Vickers Vimy Trans-Atlantic Flight MARCONI V.T. | $7.%each | Standardized Socket . $1.50 additional Agreements recently effected have made vacuum tubes available for experimental use. The Marconi V. T. is the only vacuum tube, or audion, which may be sold to amateurs, laboratories, schools of instruction and experimenters Fleming Pat. No. 803684 De Forest Pat. Nos, 841387-879532 A highly developed, all-around tube for use as a detector and amplifier in wireless communication. It has practically the same electrical constants as | the tube used by the Allied armies and navies | throughout the war in continuous wave transmis-| sion and reception. | The approximate operating life of the MARCONI V. T. is 1,500 hours. Class I—Designed for use as a detector; operates with plate : potential of 20 to 60 volts. : Class II-—-Designed for use as an amplifier; plate potentials from 60 to 110 volts may be applied. Tubes in either class may be used for detection or amplification, but those of Class I are best as detectors, and Class. II tubes are superior ‘as’ amplifiers. j ' H SEND ALL REMITTANCES WITH ORDER TO COMMERCIAL DEPARTMENT __—_O»# Marconi Wireless Telegraph Co. of America § Sole distributors for De Forest Radio Telephone & Felegraph Co. Room 1868 Woolworth me a 233 Broadway, New York Te awn Sa wo. Phe SSeS SGT SS ont

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transmitter, a 100-watt air- craft type being used. This works on 600 meters usu- ally, and is for communica- tion with mercantile craft. It has a safe range of 120 miles. But out on the At- lantic we once did as much as 300 miles, picking up Cape Race on the south shore of St. John’s, New- foundland, with no trouble at all. “In thiscarthere is also an intercommunicating tel- ephone control board for speaking with any of the engine gondolas to the rear of the ship and other neces- sary points about the hull. We find this communicat- ing set exceedingly conve- nient. When a ship is as long as this oné—640 feet—one cannot always be running about after information. So here in the forward gondola we have this in- tercommunicating unit as a sort of nerve center for all the ship’s activities.” “For the sets four stor- age-battery units are carried,’’ ex- plained Lieutenant Durrant. ‘‘Two of these are of 12-volt, 80-ampere rating, and the other two have a capacity of 40 amperes at eight volts. A charging set for these batteries is carried on board. It consists of a Brolt dynamo, giving around 12 volts atitsterminals. Thisis driven by one of the big propeller engines in the rear of this control car or gondola forward. Suitable shafts and gearing connect the generator to the engine. “The airship has but one receiving unit. This was especially designed by the Experimental Department of the British Air Force. It consists of three British Thompson-Houston vacuum valves operated in cascade. Its plate voltage is 100. About 75 flashlight batteries in series provide this poten-

Control ‘car, or ep SO of the R-34, showing her. wireless ** cabin. - During her stay in the United States :it-was neces- — sary fordetails of‘soldiers constantly to hold the -dirigible to the ground’ in this way because of the changing winds’ 114

Popular Science Monthly

Lieutenant R. F. Durrant, of the Royal Air Force, radio officer of the R-34, holding the ship’s spare 250-watt tube—valuable property tial. The. receiver has a 200- to 10,000-meter wave-length range. “Two wavemeters are carried. One works normally 1,000 to 2,000 meters. A multiplying switch jumps this from 2,000 to 4,000. The other set is a larger model of the first-named, and operates up to 10,000 meters. “You will note one especially in- teresting fact about this wireless cabin. A thick layer of hair felt on the inside walls shuts out practically all outside noises. Indeed, I have found that sitting in here, the ship seems to glide almost as noiselessly as an electric taxi over city asphalt. Of course most of the sound that may bother one comes from the engine in the rear of this particular gon- dola. When it runs I need my sound-proof room mos?. ‘‘All the sets use one aerial. It con- sists of 450 feet of 16-strand copper wire. <A_ sturdy nine - pound lead weight hangs at the end of this cable. The weight is of streamline form, has tail fins, and all in all it looks very much like a miniature of the R-34 herself. “It is but eight or ten inches long and about two inchesin diameter. Tied to the end of

the latter to hang downward and to “the rear in sort similar curve. thecable, it causes: of a parabolic or - ‘ Y

Page 101

—— September, 1919 “Do you see that aneroid barometer up there near the ceiling? It tells me how high up we are, since air-pressure increases aS one nears the ground. When the barometer indicates that we are but four or five hundred feet from the ground, I begin to reel in that aerial. Otherwise the aerial would be likely to catch in a tree or something and be torn off. “All through the voyage the radio- compass was of greatest use. It is a large framework affair up in the hull of the ship itself, and of common build. General Maitland’s log of the voyage will tell you of a few specific instances out of a great many when we used the radio apparatus and compass to ad- vantage.” Here are excerpts: Time, 11 A. M., the first day out, July 2. (Started from East Fortune, Scotland, near. Edinburgh, at 1:42 this morning.) Position now: ‘Two hundred miles out in Atlantic from northwest of Ireland. We are in touch with East Fortune, Clifden (on the west coast of Ireland), and Ponta Delgada, Azores. Messages wish- ing us good luck are being received from Air Ministry, and H.M.S. Queen Elizabeth. 3:15 p.M. Durrant, the wireless officer, reports he has just been speaking to St. John’s, Newfoundland. Rather faint but quite clear signals. As we are still in touch with East Fortune and Clifden, and have been exchanging signals with the Azores since reaching and passing the Irish coast, our communications seem good. 4:30 p.M. Tramp steamer S.S. Bally- gally Head, outward bound from Belfast, destination Montreal, picked up our wire- less on their Marconi spark set, which has a range of thirty miles only. She heard us but didn’t see us, as we were well above and completely hidden by the clouds. She gave her position as latitude 54 degrees 80 minutes north, longitude: 18 degrees 20 minutes west, and reported as follows: “Steering south 80 west true, wind north, barometer 30.10. Overcast, clouds low. (Signed) Suffren, Master.”” They were very surprised and most interested to hear we were R-34 bound for New York. 5:30 P.M. Messages received from both H.M.S. battle cruisers Tiger and Renown, the ships previously sent by the Ad- miralty out into the Atlantic to assist us with weather reports and general observa- tion. They reported respectively as fol- lows: Tiger: Position 36 degrees 50 minutes north, 36 degrees 50 minutes west. Renown: west. Cloudy. Visibility, four miles. 6.55 P.M. Wireless message from Air Ministry via Clifden states: ‘‘Conditions unchanged in British Isles. Anti-cyclone persistent in Eastern Atlantic—a new depression entering Atlantic from south.” 12:45 P.M. next day, July 3. Durrant is speaking S.S. Canada on our spark wire- less set, so there may be some chance of our seeing her shortly, as the sea is temporarily visible. The second wireless operator obtains the Canada’s direction on our directional wireless, so we may know in what direction to look for her. All that we know at the moment is that she is some- where within 120 miles. Captain David; in command, wishes us a safe voyage. We gaze through our glasses in her direction, but she is just over the horizon. 9 A.M., July 4. The ice is blue-green under water with frozen snow on top. A message reaches us from the Governor of Newfoundland: ‘On behalf of Newfoundland, I greet you as you pass on your enterprising journey.” Landed 1:54 p.m. Greenwich .mean. time, or 9:54 a.m. U. S. summer time, Sunday, July 6, 1919, at Hazlehurst Field, Mineola, Long Island. Total time, entire voyage—108 hours, twelve minutes. 60 degrees north, 25 ; \ We. are now over a- large ice-field, and the sea is full of icebergs. «. Logical Place to fill responsible positions. 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GREE course needed. Men who are masters of this profession are scarce. “The demand for Finger Print Experts is great. Asa special inducement we will give you free of charge our new easy reading course in Secret Service Intelli- gence if you act at once. Be a Finger Print Expert Build up a business on the basis of a trained brain. You can do it as a master of the Finger Print profession. There is crying need for Finger Frint Experts right now and the demand for these trained men is growing every day. A profession that offers wonderful oppor- tunities for advancement. Governments, corporations, police departments, insti- tutions and individuals have constant use for these specially trained men. The work is fascinating and The Pay Is Big ! My Sreec Finger Print Experts are Popular Science Monthly a Workings of the Radio Compass HE “loop” antenna is the basis of all radio compass action. It is nothing more than many turns of wire wound around a frame, usually square. This frame is sometimes made eight or ten feet on one side, though smaller sizes will work satisfactorily with enough vacuum valve amplifiers in the circuit. The frame has a central axis, like a revolving door in a post-office or other public building. It is rotated about this central axis by hand until the op- erator hears By A. K. Dyall fraction of a degree of the absolutely correct point. Owing to a loop aerial’s peculiar characteristics, he knows, as we said before, that the loop is now exactly crosswise of the direction from which the signals are coming. So, if he has previously affixed a pointer to his aerial shaft that is at right angles to the loop’s plane, he knows that the pointer is at this instant pointing directly toward the sending station, or else directly away from it. In either case, the pointer is indicating a line that Passes a loudest directly sound in his through the receivers sender. from the sta- If a vessel. . tion whose at sea hap- . steady send- pens to be ing he is lis- tening for. When maxi- mum sound comes, he knows that his loop is now “point- the sending station, it is easy to tell which end of the indicat- ed line ‘it ig on, since it would natu- ing” toward rally be out the sending at sea and Two operators’ booths out of many at the large compass control station in New York. These No special education is necessary. You can become a master of this profession all others. They are important men and highly regarded and envied by every one. Mail the Coupon Get full information about this great pro- fession and our big offer of a free course in Secret Service Intelligence. The mas- tery of these two closely allied professions places a brilliant career within your grasp. Achievements that will immediately place the stamp of success upon you, are now possible. Send this. coupon for full in- formation NOW. University of Applied Science Desk 1206, 1772 Wilson Ave.. Chicago Gentiemen: Without any obi'gaticns whatever, send me your new FREE book cn Finger Prints and your offer of a free course in Secret. Service Inteiligepce RE GE Ge Sy ek | a ey : Maa es OER, sss haces bacbrccccccesvecs.. ‘ A new type of e Forest Au- dion—Type P.. 100—Audion Control Box combining in a single compact set the Peer- less De For- est Audion Detector, os- cillator and au- dion amplifier, built for the audion as only the makers of the audion. can build it. No other set like it has ever been built to sell for less than $150.00. Our Price without the-bulb $65.00. We also have lower priced models. ii DE FOREST RADIO TEL. & TEL, CO. 1391 Sedgwick Avenue ~~, New: York: City 1 at: Pa -ship. . He radios the: . information-te the ship vane points toward the direction from which the wind is coming. He usually has trouble, however, in telling just the place, in his rotating of the loop, where signals are coming in loudest, just as you have trouble in telling which of two or three church bells may be making the most sound when they happen to be ringing in your neighborhood. Being so nearly alike, you are unwilling to trust your ears. The radio operator has the same difficulty. But if he turns his loop aerial crosswise to the direction from which signals are coming, like turning a weather-vane crosswise to the wind, the signals he is listening for drop out, or at least become very faint indeed. It is easy now, in his rotating of the aerial loop, to tell the point where sig- nals become the very weakest. . In fact. he can locate his loop within a by studying at home in your spare time. station, just men talk to vessels far at sea through remote not at the Expert Finger Print men travel all over asa weather- control of near-by coastal radio stations end of the the country solving mysteries that baffle : line that lies inland. In case the radio com- pass station happens to be dealing with a sender whose identity is wholly unknown (that is, whether it is at land or sea), there is another method of de- termining which end of the indicated line the sender is on—this method having to do with a rotatable loop in relation to a fixed aerial. The details of the method are somewhat compli- cated, however, and there is no space here to go into the subject. As a result of the careful researches carried on by Kolster, Forbes, and Taylor and Dr. Austin, the navy’s radio wizards, at the Bureau of Standards, the complete theory of radio compasses was worked out two or three years ago, in every particular, and some important facts brought out which had troubled experimenters for years. It was found, for instance, that, with powerful amplifiers, every foot of antenna and receiver connect- Radio compass opera- tors, from their stations near the mouth of New York harbor, have just sent in to control station the radio com- pass bearings of a ship at sea, heard calling. By pulling strings out of holes in a map | which’ correspond to the reporting opera- ‘tors’ locations, the op- erator lays off the |; bearings given. He | finds these all inter- | sect atone point. This | is thé location of the 116 ite

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Far out on sandy capes and beaches, navy radio compass men sit in little houses like this listening for the calls of ships at sea. Acopper floor shields sensitive apparatus ing wire acts as an antenna, and must be covered with tinfoil or run inside a metal pipe or tube, or false indications will result. In the finest researches, the receiver was placed in a copper gauze room, and it was found that opening the door of the gauze room a fraction of an inch let in outside dis- turbances. It was found that ‘the direction indications of the radio compass were sometimes very inaccurate; for in- stance, in a station with a radio tower the coil would always have to point at the tower, and in some locations aboard ships no satisfactory results could be obtained. Experiment showed the compass to be right, but that the waves swung around when they strike any metallic or conducting object, and seem to come from an entirely different direction. eram, Page 118. In this respect they cot much as water waves, or even light waves, going around an object. For this reason, compass stations must be placed far from danger of interference, and careful study and tests are made of each station after locating. With a mass of accumulated knowl- edge as a guide, a number of radio compass stations were built.along the

“ANTENNA

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Detail of the apparatus within a ‘ radio compass station of the kind shown at the top. of this column

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PATENTS Write for free booklet Terms Reasonable Highest References Best Results Send model or drawing for preliminary examination and report as to patentability ALL BUSINESS GIVEN PROMPT AND PROPER ATTENTION WATSON E. COLEMAN, Patent Lawyer, 624 F St., Washington, D.C. CAN YOU think of a simple, practical idea that will fill one of the many re- quests we have on file for new inven- tions? It may mean a fortune for you. Thousands of things are needed R1GHT Now. Your brainscan help. Send to- day for our great new book—“‘Inven- tions and Trade Marks, Their Protection and _ Exploitation’’ and learn more about making money from ideas than you ever knew before. It tells many things that are wanted, too. A postal will do— it is free. PATENTS ADVERTISED For SALE FREE We help our clients, without charge, to get the dollars out of their ideas—having facilities none others possess. RAMS In INVENTION And ho pon oa MANUFACTURING AMERICAN SUPPLEMENT. Published for the man with an idea. INDUSTRIES, INC. Send for free sample 201 Patent Dept., copy. One year’ssub- WASHINGTON, D. C. t scription 50c. OFTI The National Credit Jewelers i Dept. 871 108 N. State St. CHICAGO, ILL. D J J Select Christmas Gifts From It shows over 2000 illus- Our Catalog trations of Diamonds, Watches, Jewelry, ete Whatever you se- lect will be sent, all shipping charges paid. 11 You see and examine the article right in}, your own hands. If satisfied, pay one-fifth}. of purchase price and keep it; balance divid-\. ed intoeight y =~ amounts, payable monthly.\..:.. Watches plendid ins in 25-yearNes guaranteed Watches, on credit~Z@ terms as low as $2.50 a month. To the Cash Buyer: While our prices are lower than the cash — of other concerns, we make a discount of 8 per cent for cash in full in advance. or on delivery. Loftis Solitaire Diamond Cluster Rings >. Has the The Diamonds are Mounted S appear- = oa 2 OTT Sen Stone S Larg 94—$75 \ Y Looks likea \ Stone $250 single stone, cove, 30 Z $15 Down, a Mont! $7.50 a Month. £-~ The secret of. the rare beauty of this ring lies in .the perfectly matched stones, all the diamonds being uniform in size, quality and brilliancy; mounting is 14-karat solid gold, hand made. BROS & CO. fess STORES IN LEADING CITIES Te the Man With an Idea I offer a comprehensive, experi- enced, efficient. service for his prompt, legal + pci and the development of his proposition. Send sketch, or model and descrip- tion, for advice as to cost, search through prior United States pat- ents, etc. Preliminary advice glad- ly furnished without charge, My experience and familiarity with various arts, frequently enable me to accurately advise clients as to probable patentability before they go to any expense. Booklet of valuable information and form for money disclosing your idea, free on request. rite today. RICHARD B. OWEN Patent Lawyer 6 Owen Building, Washington, D.C. 2276-D Woolworth Building, New York City ESTABLISHED 1869 qemmmmmmen! PATENTS LACEY & LACEY Attorneys-at-Law — Patent Practice Exclusively Solicitors of U.S. and Foreign Patents. Trade-Marks, Copyrights. 645 F Street, N.W., Washington, D.C. Write Us for Our Free Inventors’ Book PATENT-SENSE ‘Protect Your Rights to Invention Write today for “Record of Invention” which ~contains=forms to-establish evidence of concep- . tion. Prompt: personal service. ~Prelimindry,ddvice , ~. without charge. _. J, (REANEY -KELLY--- - 732-O Woodward Building, | Washington, D.C. PATENTS AND a—sé TRADE MARKS 274 OURAY BLDG, WASHINGTON, D.C. DO NOT LOSE YOUR RIGHTS TO PATENT PROTECTION Before disclosing your invention to any one send for blank form “‘Evid of C ption’’ to be signed and witnessed, Establish your rights before filing application for patent. As registered paten attorneys we represent hundreds of inventors a over the U. S, and Canada in the advancement of their inventionss Terms reasonable. The form “Evidence of Conception,’”’ sample, instructions relating to obtaining of patentantd fee schedule sent upon request. Ask for them,—a postcard will do. 7? -Arithmetic of - Electricity A practical ‘treatise on electrical calculations of all . kinds. reduced.ta..a.series of rules, Popular.Science Monthly, 225 West 39th St., NewYork cor ¢.4 n . x ts ~ r % * Pane Fu ines * wy ' 118 $1.00 Postpaid. Another view inside the New York radio compass control station. The wires lead to compass stations on the beaches and capes Atlantic coast. These have since be- come rather famous, and are proving very useful in guiding vessels into harbors in fogs, mists, or on dark, rainy nights. At New York harbor, for instance, stations at Montauk (east end of Long Island) and at Fire Island, Rockaway Beach, Sandy Hook, and Mantoloking, N. J., get radio compass bearings on any vessel that, entering the harbor, desires the service, For instance, a ship calling NAH (New York) may be picked up by any of the stations, or by the Communica- tion Office (on top of a tall office building downtown) directly. Within a few seconds the operator in this office proceeds to answer. By the shift of a plug his key may control the transmitter at any of the Navy stations within the district, such as Navy Yard, Bush Terminal, Fire Island, and other points. He tells the ship to send out a given call steadily for one minute, say. Meanwhile the radio compass sta- tions from Fire Island to Mantoloking, on the New Jersey coast, are getting compass bearings on the ship sending out the call. They rush their readings How stand- pipes, steel tow- ! ers, or other STAN DP! PE metallic bodies / distort radio waves. At A the compass A B is pointing ac- \ curately; at B FALSE. * it still faces the ae iNDICATION waves, but is pointing wrong by telegraph to the man at the central compass control station at the Radio Communication office. He immedi- ately plots the readings on a map. This is done by a clever but ex- ceedingly simple device. The photo- graph at the bottom of Page 116 shows details. The device consists merely of a large-scale map set on a table with some disappearing strings and weights.. Each string is swung into the direction reported from its station, and all cross around the average position of the ship, showing up very clearly the latitude and longitude of the ship desiring its location. This position is then read off, and transmitted: by again: using “‘remote control” of the station nearest the ship. Time for this complete opera- : mw Popular Science Monthly — .

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ork radio es lead to and capes since be- proving els into nm dark, harbor, A ontauk | at Fire ly Hook, 2t radio sel that, Service, g NAH ) by any munica- ll office Within in this By the itrol the . Navy such as il, Fire tells the steadily ass sta- oloking, getting sending eadings / \ \ \ ALSE * \DICATION central » Radio mmedi- ap. ut ex- photo- . ge 116 -onsists st on a strings swung om its 1d the. howing e and ng its ff, and — remote — st the | opera- ~ September, 1 919 tion (or, rather, cooperation), six min- utes; accuracy, better than thirty yards per mile of distance offshore. The ship receives the message, now knows its position accurately in spite of the fog or rain, and proceeds on its way securely, knowing exactly where ‘to look for the Channel, and where it AERIAL RADIO COMPASS LOOP | | ! wu yur UN Oe CROSS SECTION OF WAVES How the radio compass loop faces an oncoming wave. Minimum sound now heard. Index points to sender A COMPASS LOOP Cross- sections of wave and {i loop when loop (not index) “points”? to sending sta- tion: 7. e., is edgewise to it Highest References New York Offices 1001 Woolworth Bldg. PATENT Prompt Service VICTOR J. EVANS & CO., Patent Attorneys Philadelphia Offices 135 S. Broad Street Main Offices: 760 9th Street, N. W., WASHINGTON, D. C. GENTLEMEN: Please send me FREE OF CHARGE your Book as described above, Reasonable Terms Pittsburgh Offices 514 Empire Bldg. SOSH e eee ew eee ete HH ee eeeeeeeeeeeeeeee TRADE-MARKS COPY.RIGHTS Before disclosing an invention, the inventor should write for our blank form “EVIDENCE OF CONCEPTION.” This should be signed and witnessed and if returned to us together with model or sketch and description of the invention, we will give our opinion as to its patentable nature. Our Illustrated Guide Book, HOW TO OBTAIN A PATENT, | sent Free on request. Contains full instructions regarding Patents, Trade-Marks, Foreign Patents, Our Methods, Terms, and 100 Mechanical Movements illustrated and described, Articles on Patent Practice and Procedure, and Law Points for Inventors. ee | Pea \—GOOMETERS Maximum signal now heard because current going up A is larger than at B. When loop is cross- wise to wave, A and B are alike must go to keep away from reefs or other sources of danger. The boys in the radio compass sta- tions, who, by conscientious watch- keeping (a religious principle with the boys who wear the Navy “sparks’’) and accurate manipulation, make the system a success, are kept in touch with the whole system by a weekly bulletin edited by Lienheart Appleby, of the office.of the Director of Naval Communications, and next to a gen- erous “‘liberty” they prize most highly an item like this: Extract from office report made by eonageaniaaal Officer U.S.S. Bounding ess: “At 2.80 a.M., April 29, 1919, while en route from Delaware Breakwater to New- port, R. I., a radio fix was requested and the following obtained: Montauk Point, 193 degrees Sandy Hook, 104 degrees Mantoloking, 85 degrees These bearings give the position of the ship as lat. 40 degrees .06 N., long. 72 .08 W.; the ship’s position by dead reckoning was lat. 40 .08, long. 72 .07 W. Notice that the ship’s position by the compass readings was only a very small fraction of a degree off that given by dead reckoning—this last method of calculating being based on the ship’s speed and course by ordinary calculation. That the compass read- ings and the dead reckoning result should agree so closely reflects un- usual credit on the Navy men. Much like lighthouses, radio com- pass stations along the coast are iso- lated and lonely. They, too, render a valuable service to ships at sea. PEL SRR ee RTE Tee teers ett PATENTS nd Trade Marks Send sketch or model for actual search and report. Write for Book- let of instructions on patent practice and procedure. Prompt personal service.... Geo.P Kimmel Patent Lawyer 39-X Loan and Trust Building, Washington, D. C. PECTESUCQUSCL GUDSLOCELER ESE DP Care e aera rae atine Ce teateaetenaveteresacen diese SUPP GED EP Teepe ~ = ~ - - _ - a - ~ - “ - - ~ = ~ - - - - - - > ~ - - - - 7 Outerrtveae Making Your Invention a Financial Success How best to dispose of your invention What kind of agreements to make for your protection What kind of offers and mistikes to avoid Valuable tables and other data By M. G. Delaney, an experienced inventor, in The Inventor’s Manual of Va‘uable Information $1.50 per copy, postpaid Additional information and Table of Contents will be mailed on request. G. E. Perry Company, Publishers, 1328 Broadway, New York Before applying for a patent you should send us a sketch or model of your invention, with a description of it, and receive our “‘Evidence of Con- ception” form—our Opinion as to the Patentablé Nature of your In- vention, and our advice regarding the best way of obtaining patent protection. Our practical experience covers a period of twenty years. Our Handbook on Patents HOW toOBTAIN - PATENT jsa storehouse of valuableinformationand / B\ advice toinventors. All communications. Hh trictly confidential. Write us TODAY, P San cea Cache say 2 en yee a rem aN ee ip NO GON PPE am eG aN aes TRADE-MARKS REGISTERED Eighteen Years’ Experience. Terms on request. ROBB & ROBB, Attorneys at Law Specializing in Patent and Trade-mark Practice exclusively 1336 Schofield Bldg., Cleveland, Ohio, Instructions and 840 Southern Bldg., Washington, D.C. ATENTS PROCURED and will give our opinion as to. its patentable nature. RANDOLPH & CO. 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, potest cocoo-------- 130 F St, N. W., Washington, D. C. 119°

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Furnish 2 to 3 Rooms for 17c a Day Now you may furnish anew one room, ora whole home on the most convenient terms im- aginable. Take two years to pay for Furnish- ings bought on this new Factory-to-Family Plan. - Payments as low as 17c a day. 800 Larkin Home Furnishings on Easy Monthly Payments Compare quality and price of Larkin Furnish- ings with furnishings offered by others. Our quality is the highest. Our low Factory-to- Family prices will save you many dollars. Before buying your Furnishings this season learn about this offer. W This Big 104-Page Book FREE Larkin Book of Better i} Homes will help thousands / this season to “‘Better Homes.” / Your copy sent IK REE now for asking. Desk FPSM-919 Buffalo, N, Y. BUCHSTEIN’S FIBRE LIMB soothing to your stump,— strong, cool, neat, light. Easy payments, J Braces for all Guaranteed 5 Years deform- Send for Catalog Today ities, P. BUCHSTEIN CO., 113 6th St. S., MINNEAPOLIS, MINN. "DEAFN ESS IS MISERY I know because I-was Deaf and had Head Noises for over 30 years. My — Antiseptic Ear ims restored r py ner eantr Head Noises, = oe iny Megaphones. nnot is caused by Catarrh or Perforated, roe i or Wholly Destroyed N. zh or by Pes Ea: easy to take out. —_ ccm Contec expensive. for Booklet and my ate etatement of how 1 recovered my hearing. A. O. LEONARD Suite 301,70 Sth Avenue - - New York City =a ay ACCOUNTANCY Wirite For FREE BOOK interationa! Accountants ‘Chicago Learn to Dance! You can learn Fox-Trot, One-Step, Waltz and latest ‘“‘up-to-the-minute”’ society dances in your own home by the wonderful Peak Sys- tem of Mail Instruction. New Diagram Method. Easily learned; no music needed; tho ds taught fully. \ Write for Svecial Termis. Send ‘today for FREE information and surprisingly low offer. PROF. W. C. PEAK, Graduate of Castle House Room 101, 821 Crescent Place, * CHICAGO, ILL. urn LAVEN ke and cook MakeYour § Te A Gas e Slave Popular Science Monthly Telephoning Electrostatically—A New Radio System OST radio men are familiar enough with the ordinary cir- cuits of radiotelegraphy. Many even have a good working knowledge of radiotelephony. But comes now Earl C. Hanson, of Washington, D. C., with a system quite unlike anything in the familiar run of cir- cuits and principles. His is an audio-fre- cuit of the system quency wireless system. cedaenmndin The fundamental idea back of it is made clear Earl C. Hanson and his electrostatic phonograph. Records are announced by his speaking in the transmitter by the small wiring diagram on this page. Briefly, the aerial is energized, and waves are sent out by a trans- former directly controlled by ordinary telephone transmitters. It is almost as if a common telephone were pro- vided with a little larger induction coil than ordinarily, and-thereby made into a wireless telephone—surely a simple process. _. ‘It should be stated, however, -that in the Hanson system several transmitters, usually three, are used to control currents going to the primary of the transformer, each transmitter having its own winding on the transformer, but receiving the sound impulses from a man’s voice, or a phonograph, or from some other source, through’ a common sound- The Walter - Hospital’ in, ‘Washing- | ton where the apparatus is now working 120 Fundamental cir- 480 TURNS NOG DCC WIRE PER. a 50.000 TURNS NO40 ENAMEL — COPPER WIRE = feeding tube. See drawing on page 122. That the apparatus “works” jg demonstrated by the fact that Mr. Hanson has long had phonograph- operated wireless sets in operation, one of them being recently installed in the Walter Reid Hospital in Washington. In this system a phonograph plays music or such other selections as may be desired into the transmitters of the set. The drawing on page 122 makes the details clearer, All that a patient has to do in order to receive is to attach one of the plain wire terminals of his ordinary telephone receiver to the springs of his bed, a steam radiator, or almost any other con- venient metallic object. The other terminal of the receiver ends in a metallic handle which he holds in his hand. Thus the bed-spring, or any other metallic object, and himself form the “aerial” and the “ground”’ of his receiving circuit. A curious fact is that the tighter the patient squeezes his metallic han- dle, the loud- er he hears the music. He can thus vary the in- tensity to suit his feel- ings at the moment. Moreover, the feature gives him something to experiment and play with. That the appara- tus has to cleave to au- dio-frequen- cies is made obvious by the fact that the trans- former has an Patient’s receiving ap- paratus. One receiver terminal ends at the metal handle; the other clamps to bed-springs ’ Army convalescents listening to music wireléssly.” ae patient has a receiver ie

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a ne df a eer ee - UH ‘‘ The president called me in today and told me. é for promotion three months ago when he learned I was studying at home with the International Correspondence Schools. “$100 a Week, Nell! Think What That Means to Us!” ‘“‘They’ve made me Superintendent—and doubled my salary! can have the comforts and pleasures we’ve dreamed of-—our own home, a maid for you, Nell, and no more worrying about the cost of living! Now my chance has come—and thanks to the I. C. S., I’m ready for it!” Thousands of men now know the joy of happy, prosperous homes because they let the International Correspond- ence Schools prepare them in spare hours for bigger work and better pay. You will find them in offices, shops, stores,mills,mines,factories,on railroads, —everywhere. ) Why don’t you study some one thing and get ready for a real job, at a salary that will give your wife and children the things you would like them to have? You can doit! Pick the fosition you want in the work you like best and the I. C. S. will prepare you for it right in your own home, in your spare time—you need not lose a day or a dollar from your present occupation. Yes, you can do it! More than two million have done it in the last twenty-seven years. More than 100,000 are doing it right. now. Without cost, without obligation, find out how you can join them. Mark and mail this coupon! iA ADVERTISING SALESMANSHIP Traffic Management BUSINESS (Complete) Commercial Law Certified Public Accountant Higher Accounting Railway Accountant BOOKKEEPER Stenographer and Typist Good English Window Trimmer Show-Card Writer Sign Painter CIVIL SERVICE Railway Mail Clerk Mail Carrier CARTOONIST Illustrator Perspective Drawing Carpet Designer Wallpaper Designer Bookcover Designer TEACHER Common School Subjects High School Subjects athematics AUTOMOBILE OPERATING Automobile Repairing Auto, Electrical Work Name ELEOCTRIOAL ENGINEER Electrician Electric Wiring Electric Lighting Electric Car Running Heavy Electric Traction Electrical Draftsman Electric Machine Designer Telegraph Engineer Telephone Worx ARCHITECT Architectural Draftsman Contractor and Builder Building Foreman Carpenter Concrete Builder PLUMBER Eee FITTER Plumbing Inspector Foreman Plumber OHEMIST Analytical Chemist MINE FOREMANORENGINEER Coal Mining Metal Mining Metallurgist or Prospector Assayer TEXTILEOVERSEER ORSUPT. Cotton Manufacturing Woolen Manufacturing He said he picked me ul Now we FVIII AUNT INTERNATIONAL CORRESPONDENCE SCHOOLS BOX 7652, SCRANTON, PA. Explain, without obligating me, how I can qualify for the position, or in the subject, before which I mar MECHANICAL ENGINEER Mechanical Draftsman Machine Designer Machine Shop Practice Boilermaker or Designer Patternmaker Toolmaker Foundry Work Blacksmith Sheet Metal Worker STEAM ENGINEER Stationary Fireman MARINE ENGINEER GAS ENGINE OPERATING Refrigeration Engineer OIVIL ENGINEER Surveying and Mapping R. R. Constructing Bridge Engineer SHIP DRAFTSMAN Structural Draftsman Structural Engineer Municipal Engineer NAVIGATION Motor Boat Rann'¢ sag AGRICULTURE Italian Fruit Growing Vegetable Growing Live Stock & Dairying POULTRY RAISER Occupation and Employer. Street and No City Staite. 121 (a as +

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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. | SCIENTIFIC | AMERICAN See eer ee sectet aoweel t it a spec appea 1 to the inventor. Each issue contains a ption of a 1 large number of recently pat- i ented inventions. Pending pat- ent tion as well as the most recent rulings of the j nage Office and the courts in its columns. / | t MUNN & CO. SOLICITORS OF PATENTS 1 | 683 Woolworth Building, New York 624 F Street, Washington, D. C. Tower Building, - Chicago, IIl. HE average boy hates school. He sees no reason for it. He ys in way ust} how much Schoot really means to them! The Se of The American Boy ass Ww. r, a lene writer with 000 boy readers, to do just this. ra year spent with prac- tical educators everywhere he has - . written ‘‘ High Benton’’, about a boy whe first ees school and why he came to like it. nf ney story starts in the a tk It’s an entirely diffe: pont AB fascinatin, — ly. He'll ie it himself "at puts school in a new light. Gives absorbing the Boy. Buy it at Sas. 20c, or subscribe, “Fhe 8 Sprague Dept-28, Detroit, Mich, + | : Oo., ~ ‘This Car. This nifty little car y gasoline motor, can be built by any boy. Parts are oe ajehod by = list of yor ah iron core. This confinement to audio- frequencies is what differentiates the system primarily from practically all others. Edison, Dolbear, Ruhmer, and others, experimented with a com- municating system somewhat along this general line years ago, but not in the perfected form that Mr. Hanson has finally evolved. The idea has The phonograph from which all the’ music comes. An attend- ant in the library operates it Coast: Defense Units Now Use Radio ing good use of the radio ex- perience gained through the war, experimenting and perfecting appara- tus continually. Only recently the Army was successful in an especially noteworthy feat. Flying nearly a mile high over Fort Hancock (Sandy Hook), N. J., re- cently, army observers in two: air- planes directed the fire of twelve-inch guns on a target nearly fifteen miles out at sea. A third airplane at an altitude of nearly three miles observed the firing of the shots for visibility. The firing lasted an hour and fifty minutes.. A total number of thirteen shots was fired. Mostly the shots enclosed, or “bracketed,” the target within a radius of 450 feet, which means that if the target had been a big battleship it would have been hit. The first shot struck two miles from the target, but after that the target was in an exceed- ingly precarious position, since the information radioed to the gunners by the men in the airplanes was so much to the’ point. The experiment is considered as s of much moment to the future coast the protection of New York Harbor. 122 TALKING SWITCH HE Army and the Navy are mak-— defense of the United States, and for. Popular Science Monthly within it possibilities in the way of audio-communication with moving trains, the guiding of ships into harbors, and of airplanes to destina- tions on landing fields. Some of these applications we shall take up in later issues. This is the first time funda- mental circuits of the system have been published. The original work on the system was done in California, 9 AERIAL, | SWIVEL PLATE FOR TONE ARM TONE ARM PHONOGRAPH MOTOR TRANS- LEAD IN COMMON PRIMARY TERMINAL STORAGE BATTERY BINDING POST BATTERY CHARGING DEVICE ee _ GROUND Phonograph circuit. Schematic diagram given on page 120. This gives the gist of Mr. Hanson’s electrostatic system Current News Notes from the Radio Field IRPLANE mail service, which has been running for more than a year between Chicago and New York, is soon to be helped along by a chain of radio stations. There will be three at first—one at Cleveland, Ohio, another at Newark, N. J., and the third at Bellefont, Pa., this last to be com- pleted by the middle of September, and the others shortly afterward. Each will be equipped with a five-kilowatt spark system set, and will have two towers, two hundred feet high and three hundred feet apart. Watch will be kept for the aviators, and informa- tion sent to help and expedite their work. The system will probably be extended in the near future to Chicago, Washington, D. C., and elsewhere. The American Flying Club has established across the country a chain of radio stations capable of reporting regularly the progress of the army transcontinental fliers, and any others who set out on such a trip. Aviators will constantly be in touch with any city or town in the United States. Inthe event of forced landings or accidents, the district radio operator can sum- mon assistance. Gasoline or other sup- plies can be rushed quickly to any spot by automobile. Stations within, one hundred miles apart are in gtospec?.-

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ving into ina- nese ater 1da- een the LATED ) IN ING T the tem 1as 4in ng ny ers ors ny he ts, mMm- ip- ot ne CU. September, 1919 Diamonds “Pay as You Like. me Credit Good 10 Months Time T makes no difference how much or little you are worth: if you are honest and prompt in meeting your obligations you 1002—$50. ean buy any of the wondrously . beautiful Diamonds, Watches or Jewelry listed in the Royal Catalog, and pay for them in monthly or weekly amounts as suits your convenience. WE WANT YOUR DON’T SEND ANY CUSTOM: MONEY You will have every.ad- ‘Youjtake no risk what- vantage of the charge ever. Every article is customers who buyright guaranteed in writing in the Royal store; a and shipped prepaid, to wonderful selection,rock be accepted ONLY if bottom prices and a you like it aftera thor- ‘liberal discount if you ough examination. prefer to buy for cash Enjoy the Prestige of Owning a Handsome Diamond Nothing succeeds like success; if you are getting on in the world let people know it. Possession of a beautiful, sparkling Royal gem is a hall-mark of prosperity everywhere, and the gift of one a sur road to any heart. “Jf i’sa ROYAL it'sa GEM.” The Royal Catalog is like a walk through wonderland—the highest. class Diamonds, Watches, Jewelry, Silverware, all perfectly illustrated from photographs and priced at the lowest figures in the world for genuine, high quality goods. Read the details of how easily you can onen a regular charge account. Send for catalog today—IT’S FREE. Ask for Edition 34 po) 6-0." (0). 00 ima ROYA & WATCH CO, ESTABLISHED /895 35 Maiden Lane ~ New York IMME EEC CCMA LCA MSROARL OAL AAAS ATi TTT CL Cec ee lll UT AN EASY WAY TO MAKE MONEY -:: plod along on a small salary. Be independent. Go in the —. y.”? Others average $200 to 3 capital needed. Jobs plentiful. Every motorist a pos- sible customer. No experience needed. We teach you. SRALER Tire Repair Outfit Improved Wrapped Tread Method Used by Tire Manufacturers = Does as good work as the big high priced vu —s outfits. A boy can use it. It’s the only vulcanizer that has Automatic Heat Control, and can’t undercure or overcure a tire. wires no watching or reg FREE Book **How to Open a Tire air Shop.”” It tells how to make big money. Don’t delay. Write quick, C. A. SHALER CO. 2108 Fourth St. | Waupun, Wisconsin Double Service® From One Socket Why do without light when using your Soar light socket for the washert BENJAMIN ELECTRIC MFG, CO. Chicago New York Violin, Hawaiian Guitar Ukulele, Guitar, Mandolin, Cornet or Banjo Wonderful new system of teaching note music by mail. To first upils in each locality, we'll give a $20 superb Violin. Mandolin, kulele, Guitar, Hawaiian Guitar, Cornet or Banjo absolutely free, Very small charge for lessons onlyexpense. We guarantee succes or no charge. Complete outfit free. Write at once—no obligation, SLINGEBLAND SCHOOL OF MUSIC, Dept. 402, CHICAGO, ILL, 00,000 In Use Mostly sold through recommendation For Personal Desk or It checks mpmtelcal ny tions, {ff meni icula’ ! Buy through your wintioner.? \ Writefor 10-day TrialOffer |® P. E. Gancher, A. A. M. Oo. 148 Duane St:, New York - -Canadian Agency L PORTABLE |; |Adding Machine : ( ultip’ i Agents. wanted “:- Not Merely a Toy, It Teaches Magnetic Attraction HIS little trick is exceedingly simple, and yet serves to fix in the mind the laws of magnetic attrac- tion and repulsion more clearly than the reading of many text books. It consists simply of a magnetized needle, dipped in paraffin and floated on the surface of a bowl of water, and a fairly strong horseshoe magnet. In magnetizing the needle, it should be The uncanny movements of the needle are a source of wonder stroked, with one pole of the magnet, from the center towards one end.. Then it should be stroked from the center towards the other end with the other pole of the magnet. If these directions are followed, the needle will be uniformly. magnetized, and the magnetism will last indefi- nitely. Now place the needle care- fully on the surface of the water. If it is kept away from the edges of the bowl it will assume a north-and-south position, demonstrating the principle of the compass. If the horseshoe magnet is held anywhere within a foot or so of the floating needle it will have a decided effect upon it. In this -manner the needle can be sent over the water in any direction, or reversed by simply turning the magnet to the proper angle.—C. W. HALLIGAN. Measuring Distance between Revolving Shafts NYBODY who has ever tried to measure a given distance between two revolving shafts will appreciate a method by which an accurate measure- ment can be obtained. Two pieces of sheet-iron are cut and FOLDING RULE SHEET IRON-*% THICK Si SECTION TIGHT FIT The rule with the clamps attached is placed over the revolving shaft and an accurate measurement taken bent to fit over a folding rule.. The clamp at the left of the illustration is left open at the top so as to be able to see the dimensions on the rule. After the gages are cut they are easily bent until sufficient: pressure to hold them is evidenced.—C. VAN BERG,. Jr. 123 (rIOSNS? / () nina he on Signal Engineering { F | BOUSANDS of miles of railroad ,~ must be equipped with block signal systems. To superintend these installa- tions and to maintain the systems now in use thousands of men are necessary. Golden opportunities are now offered. Every ambitious man should write for the free book on Signal Engineering. If you join the army or navy before you have completed the course, further payments will be postponed until you return. Men Are Needed! At the present time, less than one-fourth of the Passenger lines in the i auto- ied i id.- $250.00 th is inary slay fot a Signal Bagless Wace for be Den i Send the Coupota (po yin: of Senior. P d ad. $ Dept. 1206 1810 Wilson ‘ut r= name and ad Gress in the coupon, or alet- § Ave.—Kavenswood Station ter or post card now and get Chicago, Ill. the free book about S-gnal Gentlemen:—P'!ease send me Sagmecring. Too, we will 4 absolutely free and i tell you how you can get é ra Tew, book. oo Signal the train‘ng that you lars about your greatapect tree needinorderto become J cutht other Ite aetinery under: a Signal Engneer, stood thas | assume Do ‘ou will be under no any k igation writ- ing for the book, Department 4 Name. of Sisnaing / 0 Pt) Pereeee Stronger, Clearer Voice for YOU! Weakness, huskiness and harshness banished...,.Your voice given a wonderful strength, a wider range, an amazing clear- ness. This is done by the Feuchtinger Method, endorsed by leading European musicians, actors and speakers. Use i in your own home. Simple, silent exercises taken a few minutes daily impart vigor to the vocal organs and give a surpassing quality to the tones. Send for the facts and proof. Do You Stammer? If you have any voice impediment this method will help you. You need not stammer or lisp—if you will follow our instructions. Mail coupon for free book, k Send the counon and get our free hook and litera- ture. We ‘will. tell you just. what this method Is, how it is used_and what it: will: do for you. No Matter how hopeless your. case may.seem the oreblgston on you ie pore For els fatormalign, "We - gladly send it free, postage prepa‘d. Just mail the Coupon. Perfect Voice Institute | 1772 Wiison Ave. Studio 1206 Chicage, ‘111.

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EE POTN Aa Dia DU Mes eon al DO?:PLUM & HEATIN Send for our big instructive 256 ge well-bound Handy- Man ok Catalog. Every Home Owner, Contractor, Electrician, Farmer, Factory Manager, etc., needs it. Shows over 10,000 Fixtures and Supplies in plumb- ing and heating at wholesale. how to save skilled labor, hard work and unneces- sary material by Our New Cut-to-Fit Method This wonderful book helps you select and install the proper Plumbing, Water Supply Sys- tem, Hot Air, Water or Steam lant. Besides being our Wholesale Catalog it has many te send this copy of 25c w Se ING AT LOW COST practical plans, diagrams, sketches, elevations, etc., showing how to do the work this -newer, cut-to- fit way. Any handy man with a few tools can easily do his own installing with the. aid of this New Handy-Man Book We have spared no effort and have gone to a great a to compile this valuable k. With economy still a neces- sity, it would be’ unpatriotic 2 | ve book broadcast to non-interested parties. Therefore, werequest a temporary deposit for each ch we refund on first order, or we send our Bargain Bulletin FREE, Address Today 5 Hardin-Lavin Company $500,000.00 plants behind our guarantee — Here “ a Picture of a Puncture ! -— y) Ray 3 o. A +. . .) x DL) Tire Fluid conditions on the run. wear twice as long. repair bills. bicycle and repair stores. Buffalo Specialty Co. Buffalo, N. Y. 4) There wouldn’t be any picture if that tire had been treated with NEVERLEAK Positively heals punctures and porous Makes your tires Saves expensive Get the genuine Neverleak in the yellow, white and green tube. 25c per tube at all ye y) = e3) Making Old Hand Planes Serviceable ERY good work can be done with old tools if they are in the proper condition. An old plane can easily be put into the best condition by the following method: If the plane is a wooden one the bottom can best be trued up at a wood working shop, by using the buzz planer. If this is not possible a fairly good job can be done by hand planing with another plane. This being done the plane iron must be ground. A grind- stone is good, but it must be true and straight across its face. An old plane usually has several nicks’ out of the edge of the iron, but it is not advisable to remove all of these the first time the iron is ground. We will assume that the iron is in very bad condition and that an emery wheel of about one inch thickness is the only fast grinding machine avail- able. The axis of this wheel, shown at O in the illustration, is located some 5 in. above a flat table. We should first obtain two pieces of hard wood 2 in. wide by 12 in. long and 1 in. thick. These should be screwed to the table 1 in. apart and parallel with the axis of the wheel, the ends of these pieces being shown at B. The piece D should then be made of the same ma- terial and about 4 in. wide and 6 in. long. The piece C is 1 in. wide and fits between the pieces B. Another piece, 6 in. long, should be set into the piece D, as shown, and screwed into place, the two pieces being at right angles to each other. The clamps for With a contrivance of this sort you can keep your old planes in fine condition holding the iron must be mounted upon the piece D by the use of a tight fitting hinge at G. The jaws should be made of \4-in material. The piece H is simply a block of wood to hold the jaws in any required position. By raising or lowering the jaws any angle can be ground on the plane iron. The machine should be operated by clamping the iron to be ground be- tween the jaws and setting the block H so that the iron will just touch the wheel. The iron and holder should then be moved back and forth across the face of the wheel. As the iron is ‘ground away the block H should be slowly worked back so that the iron may be gradually forced against the 124 ‘Popular Science Monthly 7 wheel. If a rounded edge is required on the tool it may be produced by rounding the pieces B and C, or by making D longer so that it may turn about a point somewhere to the left of G. The distance may be determined from the amount of curvature desired on the tool.— WALTER D. EMERSON, A Good Way to Keep the Tennis Net Taut ENNIS-PLAYERS experience great difficulty in keeping the net free from that annoying sag which makes it somewhat resemble the track of a roller coaster. A simple but effective solution to this problem consists of two blocks of wood so notched that the net rope can- not slip through them and slacken up Notched clamps hold the rope securely un- til it is necessary to tighten or release it the net. These are screwed to one of the posts, one being movable, so that it sets up against the other when the rope is inserted. This insures a tight and clean-looking tennis net. This remedy may also be applied to the clothesline.—CLYDE KEITH. How to Make Improvised Lantern Slides T is very often desired to throw upon the screen diagrams of sta- tistics or colored lights. One very simple means of making slides for these purposes is to draw or write upon pieces of sheet gelatine with India ink and mount them between two pieces of thin glass and bind the edge with passe partout tape. With a glass- cutter such as may be ob- tained from any hardware store, there will be no dif- ficulty in cut- ting glass of the proper size. Sheets of colored gelatine may be mounted in the same manner for the purpose of projecting colored lights.—FLoyp L. DARROw. THIN GLASS PASSE PARTOUT TAPE In an emergency this type of slide serves a number of purposes

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quired ed by or by y turn left: of ‘mined lesired RSON, the lence he net which track on to *ks of > Can- en up pat e of at it rope and 1 to ‘OW ita- ery ese on dia wo lge or d September, 1919 Tinfoil Used as a Substitute | Fuse HILE taking an automobile trip, a short time ago, the head- lights of my car were suddenly ex- tinguished owing to the burning out of afuse. We had no extra fuse blocks, and as the battery appeared to be unusually “hot” I was afraid of burn- ing out the lamp globes if I attempted any sort of a direct current. Suddenly it occurred to me that there were tinfoil wrappings on the package of ciga- rettes I carried. I removed this and wrapping the burn-out fuse block with sev- eral layers of tin- foil pressed it back into the clip connections. Turning on the head-light switch the lights came on, and westarted upon our trip again without further illumina- tion troubles. Tests that I In an emergency have made since this is a valuable have revealed ‘thing to know that the tinfoil will melt and break the circuit at be- tween ten and twenty volts, while an ordinary six volt headlight globe will seldom burn out with less current than eighteen volts.— JOHN E. Hoaa. Turn Old Automobile Tires into Shoe Soles OU will find that pieces from the sides of old automobile tires make very serviceable soles for shoes and will save mon- ey that would otherwise be WIRES TO HOLD TIRE spent for IN PLACE leather. Tomakethe sole, a square piece should be cut from theside of the tire where it is least worn. Tap your soles with old With ty he out- automobile tires. Such Side of thetire soles will outwear the used as the ordinary leather bottom of the sole, stretch it over the shoe by means of four wires fastened to the corners of the tire strip, as shown in the illustra- tion. The sole should now be tacked on, care being taken that the rubber does not bulge outward. Cut off the extra rubber even with the shoe and then polish. You will find that these soles last three times as long as the ordinary kind and if the job is neatly and carefully done no one will know LAST T chanic to familiarize himself with other shop lines outside his own individual work— = and that is to have spe- (Uae cialists in all lines give him FRaW all they have learned in a (ga form that will be readily accessible. There you have called ‘‘Modern Shop Practice.” A Few of the Subjects Treated | INanagers, etc. Machine Shop Prac- Metallurgy Mechanical Draw- the reason for the famous standard reference work, A surface of cast iron is to be finished in one cut on a milling ma- chine. The casting is 8 inches long and 5 inches The milling “Modern Shop Practice’’ is a wonderful reference | 2 width of 2 inches. “How long will work in Machine Shop Practice and Management, | teed of 23 inches. . Production, Manufacturing, Metallurgy, Welding, | enucx usear "7% i * masnetic Tool Making, Tool Design, Die Making and Metal | car tecnt™” "°°? fo" cutting Stamping, Foundry Work, Forging, Pattern Making, | of ter 30.30% getermine the ratio Mechanical Drawing, etc. It has been tested through | ‘fhe siven? six editions, bought by thousands of mechanics, con- | inc. What is the ratio of gears to sulting engineers, shop superin- | ‘reads per inch? tendents and owners, production J im milling machine? too e,e maker’s standpoint? Machine Shop Man- New Edi Why is it advisable to cut the agement tion threads of an adjustable tap some- = Manu- Onl y 7 C e nts a Day a cong poe the desired size Welding Six magnificent volumes, flexibly bound | 3oy, contider it advisable to use a in American Morocco, gold stamped, 2,300 | when enlarging a hole? Why? Die Making pages. 2,500 illustrations. Photographs, | 1,."injunould undue accuracy never Senet ag aa drawings, explanatory diagrams, tables, etc. | jigs and similar tools? shee se Here you have at your finger tips up to date | 4,."hat is the practical way to test Patternmaking labor-saving methods that big manufactur- How dees the sisur on eratedl ont ing, ete. ers have spent thousands of dollars to | &,tiffer from one for iron? develop. Facts that you can use in your | necessary in pouring a mold in order everyday work. Information that fits you | *% obtain the best results? to earn bigger’pay. All this is now yours in the new 6 volume J] vented when a flask is used? set of ‘Modern Shop Practice,”’ on payments so easy as to | __ What point carbon steel should be average only 50 cents a week or only 7 cents a day! ters, drills and taps? SHIPPED FREE No money in advance. Not acent. See the books in your | the, diameter of the finished. pulley own home or shop absolutely free at our risk. Read them, | face 9 inches? examine them, study them for 7 whole days before you need decide whether you want to keep them or not. to get the books for free examination. Make no deposit. Assume no obligation. Simply sign and mail the coupon herewith and the books will be promptly shipped to you for 7 days’ free examination. If you are not more than delighted with the books and do not con- sider them a wonderful investment, just send them back to us, and you won't owe us a cent. If you prize the books and consider them worth many times their price to you, send only $2 within 7 days and then $2 a month until the special introductory price of $19.80 has been paid. Send No Money Merely sign and mail the coupon and the books will be shipped to you at our risk. Get the coupon in the mail at once before this special offer is withdrawn. Send it today—NOW! AMERICAN TECHNICAL SOCIETY Dept. M-206, Chicago, Ill. Extra Feature FREE! To those who order promptly, we will give free a consulting member- ship in the American Technical Society for one year. This gives you the right to ask our experts any question regarding shop practice for an entire year, You the difference.—HOWARD DOMINICK. may ask as many. questions as you please. 1% Can You Answer these Questions on Shop Work’ HEskilled mechanictoday isaspecialist. Hehasnoopportunity to build a complete machine or even a small part of one. His active work is carried along rather limited lines. But to make the best success in his work—to secure promotion to more responsible duties or to go into business for himself—it is absolutely necessary that he have a broad and comprehensive knowledge of machine work and shop practice. There is only one really feasible way for the me- \ wide, cutter has a diameter of 3 inches and it take to do the work? Assume a of two gears, when the numbers of The lead screw has‘a pitch of % be used to cut a screw with 18 What determines the cutting speed Pit lly my a aha ; What is essentially the first step in making any tool from a tool- Under what é¢ircumstances would What are some of the precautions How are the sides of deep molds used for machine tools, milling cut- _ Why is it necessary to reheat large Dieces after they have been hardened? What must be the outside diameter of the original wooden pattern for the rim of a pulley with six arms to be 30 inches and the width of Send no money ' American Technical Society, Dept, M206, Chicago, U. 8. A. a Please send me set of Modern Shop Practice for seven,days’ free examination, shipping charges collect. If I déeigie to g buy T will send $2.00 within seven days and the balance. at $2.00 a month until $19.80 has been paid.. Then you sexid me a ] receipt showing that the $30.00 set of books and $12.00 consulting membership are mine and fully paid for. ‘ If 1 think I can get 4 along without the books after the seven days’ trial I will return fi them at your expense.

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There is a wonderful oppor- tunity right now for boys who like electricity. Boys who are ambitious and will train them- selves in spare time can step into good positions and get ex- perience that will give them a real start toward success in life. Good salaries are offered with rapid promotion. For 28 years the International Correspondence Schools have been training boys for success in electricity and over 200 other sub- jects. They will help you prepare right at home for a position in the line of electrical work you like best —or in any other work that ap- peals to you. Thousands of boys, through I.C.S. training, have stepped into fine jobs, but never were opportunities so great as now. _ LettheI.C.S. help you. Choose the work you like best in the cou- pon 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 ow. I Ee ee a oe FR AM OUT MERE ooo oe eee ee ee INTERNATIONAL CORRESPONDENCE SCHOOLS BOX 765 If Your Automobile Is Electric By H. Worthman, Jr. HE electric vehi- cle, whether truck or pleasure, is of necessity a city machine. The periodic recharging of the storage batteries makes it impos- sible for the car to travel very great distances from its base of supply, for the charging stations in outlying dis- tricts are few and far between. The motive power of the electric car is storage batteries, the principal The electric car is only as good as its battery; take care of it types of batteries in general use being the Edison and the Lead Plate Acid battery. The latter is widely used for all purposes on gasoline, steam or electric vehicles. The construction of a battery is comparatively simple. It consists of a positive plate (of a reddish brown color) and a negative plate (of a greyish color), separated by a ribbed wood or hard rubber separator. The framework of a plate, which, in battery technique, is called a grid, consists of lead, and into this the active material is pressed. The active material is made up of red lead mixed with proper chemicals for the positive plate, and pure lead of a spongy char- acter for the negative. A number of these plates, sufficient to give the desired amperage, are con- nected to their respective terminals and put into a container or jar of hard rubber, after which dilute sul- phuric acid and distilled water is added, which forms the electrolyte. The positive plate has a negative plate placed on either side of it. The 110-ampere-hour cells, so much used on business cars, are connected in series in batteries of 40 to 45 cells to secure the full working capacity. A simple explanation of a battery, when charging or discharging, is that the positive plate expels or breathes out the electrolyte on’ charging and soaks up or inhales it on discharging. This also explains why a battery will give greater mileage on a fresh charge. losing it when the car is left in the garage for any length of time. The best way to ascertain the bat- tery’s condition is by the use of a hydrometer syringe. A fully charged cell will read about 1275 to 1300 points 126 Popular Science Monthly and a discharged cell around 1160. A common fault is to test a battery with a piece of metal, such as a wire, screwdriver, etc., getting a spark by a direct short circuit. Don’t do this, for it causes the plates to buckle and crack. A voltmeter is the only in- strument that can safely be used, other than a hydrometer. A cell will read about ,2.2 volts on a volt- meter. When charging a battery the elec- trolyte will heat up to a degree de- pending upon the rate of charging. This causes evaporation, and the elec- trolyte must be replenished with distilled water to its accustomed level. All wiring on the car should be periodically inspected for damaged insulation, especially if acid has been spilled upon it by any mishap, for the acid eats through the wire insulation in a very short time. Bear in mind that the electrical power in a battery is limited, and everything done to con- serve it will mean a saving of expense and labor. All movable contacts should be cleaned frequently, for dirt, grease, and foreign substances prevent the controller working properly and prevent good contact being made, which wastes current. The gearing and wheels should be looked over and greased about once a year. Dragging brakes, poor contact, un- der-inflated tires, also cause a surprising amount of trouble. Be sure to keep the battery solution READING OF A DISCHARGED BATTERY ” HYDROMETER HYDROMETER. |B SYRINGE i ae VENT ST pusning VENT TUBE TERMINAL SEALING COMPOUND JAR COVER. ELECTROLYTE FILLER TUBE NEGATIVE PLATE POSITIVE PLATE SEPARATOR JAR JAR BRIDGES XPANSION JOINT WOOD CASE The storage battery is supposedly a complicated contrivance, but it’s very simple to understand above the plates. Do not let the temperature exceed 100° F. when charging. Do not let the battery stand idle when discharged. Keep the battery and all its connections clean. Follow manufacturer’s ‘instructions when charging. Use the hydrometer to ascertain the density of the solution. Avoid excessive use of current.

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September, 1919 MOTORISTS. AO SENDFORTHIS Cage FREE REPAIR BOOK Tells how to make dozens of motor repairs easily, quickly, economically with SMOOTH-ON IRON CEMENT No. 1 he book is free. Write for it. The Ce- an is 25c in 6 oz. cans, 50c in 12 oz. cans. At Hardware and Auto Supply stores. SMOOTH-ON MFG. CO. Jersey City, N.J., U.S.A. SMOOTH-ON a IRON. cENEM IRON CEMENT ay GENUINE Armstrong Stocks and Dies HINGED PIPE VISES PIPE CUTTERS PIPE AND BOLT DIES MANUFACTURED BY THE ARMSTRONG MFG. CO. 337 Knowlton Street - Bridgeport, Conn. PROFITS (Charging Batteries for YOU | ows With the HB Lighting and Battery Charging Set you can make your own electric lights for as low as 2c, per KW, and make a profit. from $100 to $150 per month on battery charging. Anyone can easily operate without experience. Sturdy, dependable, economical to oper- ate from line-shaft or your engine. Small Payments Put This Money- Maker in Your pe le fit: ‘or Dalat Abaclute Money-Back Guarantee. partment about proper size for your needs. Pin . is to your letterhead and write TODA Y for information. Big Profits in Vulcanizing y fund your money. y Y of our graduates make ver $3,000 a year. 4 Visit the city of our near- “see_all other makes their Method of doing the work; then visit our Anderson school and get our Method, Go pre- pared to take five to ten ae course of the Anderson meth- and you will know why our graduates make oe, If you do not bu: course costs you time thereafter if you buy, or if, you bay at the start, you will be paid $2 per day expense money, because we sell the work you do. % Anderson Steam Vulcanizer Co. 3 Williams Bidg., indianapolis, Ind.,U.S.A. Please print your name. We receive many we cannot make ou , and any bo Pilliod TOOL CASES EXCEL Machinists and Too! Makers find them most satisfactory in construction, appearance, Service and price. Imme- diate shipment. Booklet describing 20 styles on request. INLY 2 CE Physicians are abandoning droge for this new treatment. If your mind or body is tired, or ‘hi a tism, blood, stomach, liver, kidney and skin troubles, oper your pores, and feel the rapid change in your condition, at oss o The Robinso on have rheuma- 2c a bath. nm Bath is the only scientifically con- structed hath cabinet ever made for the - Write Agents » ROBINSON MFG. CO., 997 N. Twelfth St., TOLEDO, OHIO Improved Electrode for a Water Rheostat HE form of water rheostat usually employed for regulating current strength is made from a large glass or porcelain jar with horizontal elec- trodes. A rheostat employing vertical electrodes is preferable for the reason that any gases formed are readily released and polarization of the plates is thus avoided. Desiring to use a rheostat with horizontal plates on account of the small space it occupies, the writer de- vised a form of horizontal electrode that allowed easy escape of the gases. A strip of galvanized iron, 1 in. wide, was bent into a spiral, allowing 4 in. of space between each turn. Two strips of the iron are then crossed on the spiral and soldered to it in several places. The rod is fastened to the cross strip by drilling. With this construction the action of the rheostat is greatly improved, H = A i ole for rod ‘ ron Spiral Cross Strips 4 P| | Re) J Top view Side view of Broken view . electrode of rheostat ~~ OE Te Vertical electrodes in a rheostat permit the gases to escape and occupy but little space the circulation of the electrolyte keep- ing the solution cooler and, by carry- ing off all the gases, prevents polari- zation.—THOMAS W. BENSON. Correcting Engine Starter Trouble LARGE proportion of engine starter and lighting generator trouble is due to high mica on the commutator. This is especially true after a car has been in service for some time and is more noticeable in the generator than the starter. The copper wears faster than the mica (mica is the insulation between the copper segments) and therefore, after a time, the mica will protrude above the surface of the copper and prevent the brushes from making good contact. The usual symptoms are—dirty commutator, rapid brush wear,.squeak- ing, chattering or vibrating brushes, which results in no charging current, generator fails to supply enough cur- 127 It's easy with Red Devil’ Fingers of rbteel that make easy work of the many little household jobs your unaided hands are not tough enough to do. With . Red Dewil/ 8A 1.6 BAT NEE ~ PLIERS you can form wire into any shape for hat frames, lamp shades, etc., and for rough or delicate repair work they are always:ready with a vise-like grip and a leverage to save your bare hands and pa- tience. Your dealer will show you many styles from which to’ choose just what you need. Countless uses of “Red Devil” Tools are described in an interest- ing booklet. Write for it. SMITH & HEMENWAY CO., INC. 264 Broadway, New York City Factories: Irvington, N. J. **Red Devil’? is the Expert Mechanic’s guide to Known Quality in Pliers, Elec- tricians’ Tools, Hack Saw Frames and Blades, Auger Bits, Chain Drills, and other Hand Tools, all of a class with ‘“‘Red Devil’? Glass Cutters, the biggest sellers in the world. 10 Centsa Day Pays . : for This Symphonola Plays all records, Victor, Columbia, Edison, Pathe, Little Wender, merson. Take a year ‘to pay, after 30 days’ trial. Compare ite tone for clearness, volume, with more costly instruments. - at our expense ff it fails to make good. Ask today for the Beautifully Mlustrated Symphonola Book FREE Shows this‘ and other Symphonola ‘styles sold on easy payments. test song, Symphonola Records gt. ov, tst,cf , er ine: ¥ Prpuler full toned disc records. Playable on any Phonograph. Lathitt CO» desk SPSM 919 Buffalo, N.Y.

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Batery = For use on 110 volt, A. C., eycle, si

current snl _ 80 watis, 8 volts, Toamperes - 44-50 | spite ae $68. 50. ' Expandi di t thread to just the ri taper, Dies pete when th thread is ak oe apes reset comnts to size.: No time lost or by backing off. Built also ogee aepig a useful feature in close quarters. Ask your supply house Catalog on request THE OSTER MFG. CO. 2180 East Gist St. - Cleveland, Ohio .

ASBESTOS We are miners and shippers of Crude Asbestos in any quantity. We. produce all grades at our world famous BELL \SBESTOS" 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.

electrical,rope, air- plane, piano, pipe- organ, flat, hoops, bale-ties, tacks, nails, barbed-wire, concrete re - inforce- ment, n net- ting, wire fences, steel posts, trolle: -road Lye rail bonds, wire wheels, auto-towing es, horse-shoes, Illustrated Books Describing Uses, FREE American Steel & Wire Co. ®=*"s3;7,F.5°5-+-

BIG MONEY AND INDEPENDENCE FOR LIFE ERE is the most profitable business on earth—TIRE REPAIRING. Open a Tire ‘Repairing Shop—business pours in. Vanderpool Vulcanizer (5 Cav- ity). has capacity of $100 worth of work a day. Tremendousopportunity. Wearethe pioneers in the manufacture of the Dry Cure Vulcanizer—the only vulcanizer that guarantees absolutely PERFECT work. We send you free ‘tire repairing manual—tells everything necessary to know. Write at once for full particulars.

‘In answering aitdvess Dept.S—U

Popular Science Monthly rent to keep up the battery, conse- quently, dim lights and a dead starter, This high mica should be carefully removed with a dependable instru- ment. The tool shown in the illustra- tion performs this work very satis- factorily. It is inexpensive, the base and ends being constructed of 1 in. oak, while an ordinary machine screw or bolt can be conveniently utilized for the centers on which the armature rotates, and the centers secured in place with lock nuts. The bar, or guide, on which the cutter operates, can be of %-in. cold rolled steel, while the cutter should be made of 14-in. drill rod. The point of this cutter is ground sharp, like a parting tool on a lathe, or planer, and adjusted to the thickness of the mica between the copper bars. The armature is rotated on these centers and the cutter is operated

Automobile lighting and starting troubles are frequently due to high mica on the commutator. This machine remedies the trouble backward and forward in the same manner as a planer or shaper tool. Great care should be exercised, so that all the mica is removed, especially close up alongside the commutator bars.—D. C. GRINDELL. Three Worn-Out Dry-Cells : Make One Good One F you have three old batteries and need one good one, connect them up as shown in the sketch and all the current in them will run into No. 3 battery. Connect the zinc in battery No. 1 to the zinc in battery No. 3. Connect

When connected in this manner all the current flows into No. 3 battery the carbon in battery No. 2 to the carbon in battery No. 3. Connect the carbon in battery No. 1 to the zinc in battery No. 2. Leave the cells con- nected in this way for half a day and | the third battery will be as good as when new. When carrying out this method, it is, of course, desirable to choose the best cell of the three to

WM, VANDERPOOL CO., Springfield, O..

128 | resuscitate.—DUARD SCOTT.

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ese ted he he in id as 00 & September, 1919 First Aid for the Chemical Laboratory HEN handling chemicals to any extent it is prudent to have at hand preparations to prevent harmful effects should corrosive acids or al- kalis get into the eyes or on the hands. A neat shelf can be made as shown in the illustration and used only to hold these first-aid solutions, which are made as follows: Body—Acid Burns: Saturated solu- tion of Sodium Bicarbonate. Body—Caustic Burns: Distilled water, 95 parts; Acetic Acid, 99 per cent C.P., 5 parts. Eye—Acid Burns: Distilled water, 95 parts; Sodium Bicarbonate, 5 parts. Eye—Caustic Burns: Distilled wa- ter, 98 parts; Acetic Acid, 99 per cent C.P., 2 parts. All quantities by volume. When the body is burned by the spilling or splashing of a corrosive ata 3, ) ( i ts Wi (| h) | ay Me | With a safety-first shelf the chemist is always prepared for accidents solution remove clothing from the part and apply the proper solution freely. When acid or caustic splashes in the eye an eye cup can be used for applying the solution or pour into the eye holding the lids open. Quick action in such cases often prevents much pain and inconve- nience and one is always prepared for the worst.—THOMAS W. BENSON. A Sound Magnifier for an Electric Bell OMETIMES the electric door-bell is so placed in the back part of the house that it can hardly be heard. A larger bell means additional bat- teries and an added expenditure. To do away with this expense the writer made a megaphone out of cardboard, which he placed over the bell on the FOR TWO GENERATIONS Inspectors, Toolmakers, Machinists and Apprentices have pinned their faith to the accuracy of In the lathe room, at the bench, throughout the shop, wherever metal work requires precision measurement, you'll find men using Starrett Tools from preference: Catalog No. 21-W sent free on request The L. S. STARRETT CO. The World’s Greatest Toolmakers MANUFACTURERS OF HACK SAWS UNEXCELLED ATHOL, MASS. wall, deflecting the larger end down- A WAKLEIA & SONS ‘ 7 — | 4} ©) Every User of Tools Will Appreciate This Handy Bag Made of Harness Leather— Strong and Durable Combines all the good features of. the various common leather bags. Strongly built for rough usage. Bottom is three ply and steel studded. Has saw and bit holder, hand strap, and shoulder strap with nad. A mighty good, all-around tool bag. Six sizes ranging- from 14x 8 inches to 24 x 8 inches... Show this ad to your dealer and ask for the genuine KLEIN tool bag. If unable to get it write us. MATHIAS. KLEIN & SONS, Mfrs. _CANAL STA. 3, CHICAGO 129 Direct from Factory to You : ALL SIZES AND STYLES 2, 3, 4, 6, 8, 12, 16, 22 and 30 H-P. LOW PRICES Don’t wait if you need an engine for any purpose. NOW is thetime to buy. Life Guarantee Against Defects Big surplus horse-power. Above price in- cludes engine complete on skids, ready to Hoenn se te cony ahipeseut, Write cr wire e a) . for big, new catalog of these wonderful Witte ENGINE Works - | 2223 Oakiand Ave. KANSAS CITY, "4

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Ca (iit iin Stanley Cutter and Chisel Grinder The STANLEY CUTTER -AND CHISEL GRINDER is a device for holding Plane ‘rons, Chisels, and other similar ¢utting tools that they may be ground or honed to any desired angle or bevel, insuring an ac- curacy that is very difficult to obtain when the tool is held in the hand. The tool to be sharpened is rigidly held in the Grinder by thumb screws, and may be given any desired angle by means of the large screw attached to the roller frame, which raises or lowers the main body. As shown in the cut the Grinder is fitted with two - thumb screws and_ three thumb screw holes. By the use of the twothumb screws, the, tool to be ground is held much more firmly than is possible with the use of a single screw. The Sharpener is made en- tirely of metal, all parts being nickel plated. Special circular upon request TANLEY Rute & Levet Co) New Britain, Conn. U.S.A. -ward at the angle towards the center of the room. This enabled even a deaf person to distinctly hear the bell A megaphone set over the doorbell would even make a deaf person hear and it could also be heard with perfect ease from all parts of the house. This ingenious arrangement lends itself to outside bells to even better advantage. It could be used on out- door telephone bells and yard bells, for instance.—JAMES M. PURCELL. Extracting a Cork from the Inside of a Bottle HEN a cork slides down inside a bottle it is very difficult to get it out unless one has the necessary tools, and they are not always avail- able. A good way to extract it is to grease the neck of the bottle with vaseline, then hold the bottle under cold water. © When the bottle is as cold as possible spear the cork with a hat pin, or even shake it until it blocks the neck of the bottle and sets straight with the neck. Then gradually heat the bottle or pour Pour hot water on the iced bottle and out pops the cork _ hot water over it and the expanding air will generally force the cork out with a slight pop.—VicTor H. Topp. . . 130 Popular Science. Monthly — A Gage that Tells How Hard the Wind Blows S a companion to the weather-vane every dweller in rural districtg should have a wind-pressure gage by which he can determine the velocity of the wind as well as its direction. The one shown here is very simple in con- struction and operation, will estimate, roughly, the wind’s velocity, and can be read at a glance. The vane A is constructed of a %-in. board 36 in. long and 8 in. wide. Groove out the top edge with a gouge and fit a length of smooth bore pipe B, 1 in. inside diameter, along this groove, fastening the pipe to the wood by means of a lug at each end, as shown. The vane is kept from warping in the weather by a piece of strap iron CC, bolted through at each end. At one end secure two angle-irons DD sufficiently far apart to take a common spring scale E when extended “AND 15 Yelb = 15 M. PER HR. 4a" 230" «= « DETAIL OF LUG “L” This wind pressure gage is easily taken off and stowed away when not needed the full length of the scale. Just above the top angle-iron insert a small pulley F. Two heavy screw-eyes GG are then inserted in the opposite end of vane beneath a third angle iron H at the top of that end. The rod J is of round i-in. oak or other tough wood and is 5 ft. long. On one end of the rod is fastened the pressure-board J, which can be made of wood or sheet iron as desired. A block on one side of the board is furnished with a hole which makes a driving fit over the rod. This board is 12 in. square, having an area of 1 sa. foot or 144 sq. ins. Slip the rod through the tube, insert a screw-eye in the other end of rod and connect to the ring of the scale by a stout, flexible cord passing over the pulley. When the pressure board is free from pressure, about 15 in. of that end of the rod should project from the tube, while the cord should be adjusted so the scale reads at O. Provide a suitable round iron rod, for a spindle, which fits through the screw-eyes GG and bears up against the angle iron H. Mount the com- plete apparatus upon a post in a clear space where the wind blows free. Before assembling the parts, give the rod a thorough soaking in hot paraffin and give the vane several coatings of linseed oil. An approximate pressure and wind velocity scale can be painted on the vane as suggested. Such an instrument will be found handy to assist one to determine weather conditions.

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ige ipe his 0d wn, the y ons P a 2 ded od lust nall hen ane the und d is ned be red. d is es a rd is sd. sert rod cale over oard 1. of yject ould rod, the inst -om- clear give hot veral wind the yund September, 1919 A Home-Made Forge and Blower HAT “necessity is the mother of invention” is proven by the ingenuity displayed in this con- trivance, which was made to replace a high-priced piece of machinery. A discarded blower was used. A pipe with a slot cut in it was screwed to the exhaust of the blower. The end of the pipe passed through the hole of a container made from ma- The blower produces an intense heat which will quickly bring the steel to a glow terial found in a scrap pile. When completed coal was placed in the container. A handle was then attached to the pulley wheel of the blower, and the assembled apparatus mounted upon a brick base, as shown in the illustra- tion, thus making a cheap and effec- tive forge.—ERNEST SCHWARTZ. You Can Make This Vise- Shear without Cost HIS simple, home-made device is one that is well worth the making, and as it is made from a piece of flat steel and an old file it costs only one’s spare time. The stationary blade is shown in detail and is made from a piece of 3%-in. flat steel. The moving blade is made by drifting a hole through a An old file and a piece of ‘flat steel makes this handy vise-shear flat file that has been previously heated to a cherry red; then the file teeth on the cutting side are ground off and the cutting edge ground on. Now simply assemble the parts with a bolt and nut and the tool is RSQ US CAT OFF. DISSTON THE SAW MOST _4 CARPENTERS & 7 USE Z Per! @ be ¥ eS /# High-Grade Workmen the World Over Use Disston Saws RUST your practical man to know what he wants and whether or not he is getting it. The more a man knows about saws, the more experience he has had with saws himself, the more critical he is apt to be—less likely to feel that he is getting his money’s worth unless he gets a Disston. High-grade workmen all over the world know the Disston Hand Saw by actual experience—know its outstanding position as the most famous Hand Saw in the world. Every pound of steel used in making Disston Saws is Disston Crucible Steel, made in the Disston plant. And, more and more, large users of Circular Saws, Cross-Cut Saws, Band Saws, Metal-Cutting Saws, are using Disston exclusively; for in these saws, as in the famous Disston Hand Saw, Disston Quality is known as the standard. Whatever kind of a saw you need— Disston make it and make it right. Disston Saws are made in all styles and grades. The live dealers—they sell Disston Saws—many of them feature Disstons exclusively. They are good dealers to buy from—they know quality and show a desire to give quality. The free Disston Handbook on Saws tells how to select, use and care for Disston Saws and Tools. Write for it today. HENRY DISSTON & SONS, lac. “America’s Largest and Longest Estab- lished Makers of Hand Saws, Cross-Cut Saws, Band Saws, Circular Saws and Tools”’ PHILADELPHIA, U. S. A. Canadian Works: Toronto, Canada San Francisco Portland, Ore. Sydney, Australia Chicago Cincinnati Boston New Orleans Memphis Seattle Bangor, Me. Vancouver, B. C. complete.—CHARLES H. WILLEY. DISSTON SAWS AND TOOLS Standard for | Nearly Eighty Years—and Growing Faster Every Year 1]

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Th eS PS SST SS SESS Se EO FF i RS eee OS A reference book if you | Suse tools—a_ 7 guide if you / buy tools. Over a thousand small tools are listed along with many illustra- tions offering a variety from which it is easy to select the tools best suited to your require- ments. Send for this > © catalog No. 27;. it will- fit your tool kit. Brown & Sharpe Mfg. Co., PROVIDENCE, R. I., U.S.A. ACompact Kitchen Cupboard for Cooking Utensils HE average woman gives little thought to the matter of having all utensils used in cooking close at hand and convenient to the stove where they are used. Here is a clever idea for convenient “A place for everything and every- thing in its place,” is the slogan of this easily made cupboard arrangement. The cupboard shown in the illustration is built against the wall beside a gas range. Racks are provided for holding the implements used in cooking so that the housewife, can, if necessary, reach them with one hand while attending to things on the stove with the other. The cup- board is made with a rising front, to avoid having the doors swinging out over the stove. _ The rising front is simple in con- struction and is easily made. Strips of half round molding are cut to proper length and glued to a piece of oil cloth. Tacks are used to insure the strips adhering stoutly to the oil- cloth. The channel in which the rising front slides is made by laying out the pattern on a piece of board and sawing it with a band-saw, afterwards nailing the sections to another solid piece of board. Care must be taken to leave plenty of room in this channel as the front must fit very loosely in order to avoid binding, otherwise it will become jammed.—W. O. MOORE. ‘ Here Is a Transparent Drawing-Board UNIQUE and practical device is the drawing board illustrated. It is designed for copying drawings GROUND GLASS AIR SPACE PLATE GLASS It helps the draftsman or tracer ‘ to get his much wanted clear copies on-opaque paper and will even take Bristol board, through which pencil drawings will show clearly.. Popular Science M onthly A wide frame is constructed of white pine, carrying a piece of plate- glass set flush with the top. The top is hinged to a base of the same material which has been lined with bright tin. A sliding bar carries two showcase lamps whose light is con- centrated on the under part of the drawing by the tin. Ventilation and protection from overheating are pro- vided for by ground glass underneath | the plate glass with an air space between the two. The frame has a piece of felt glued to the bottom so that it may be placed upon a polished table without danger of scratching the sur- face.—HERMAN NEUHAUS. Remedying Trouble from Poor Switch Location HERE are many instances where snap switches with metal covers, or open knife switches, are placed in close proximity to grounded pipes. If the wire feeding the switch happens to be the outside or “live” side of the circuit there is always danger of get- ting a nasty shock in turning the switch on or off, as the hand may come in contact with the surface of the pipe. This condition often exists in resi- dences, and while the shock from the lighting voltage is not likely to be serious it is unpleasant to say the least especially to the women-folks. In planning a wir- ieitiltilaiee ing installation crounpep «€CCs SChs—Ss conditions | VENT PIPE §=—s Should _ be avoid- ed, but if they cannot be avoid- 3 ed, care should — be taken to have the wire feeding the switch of the TAPE, same polarity as the grounded ob- ject, that is, it should be fed from the ground- ed side of the ‘Rubber casing around cireutt. In the the pipe near the instance cited wall switch does away herein the snap with accidental shocks gwitch with a metal cover was fed from the “‘live”’ side of the line, and was mounted at the corner of a wall where a grounded vent pipe was but an inch or so from the switch cover. There was a sink close to the vent pipe and the women folks of the family often turned the switch on with wet hands and, of course, received a shock in doing so. The trouble was remedied as shown in the illustration. A section of inner tube was cut open, stretched tightly around the pipe and taped neatly in place at the top and bottom. This rubber insulating cover was neater and possessed better insulating qual- ities than several layers of friction tape. If the pipe happens to be part of the heating system a covering of fiber will be better on account of the heat.—J. A WEAVER.

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Sl- ist BaP 0 OD Dam st September, 1919 To Make a Door Open Both Ways N a great many homes it is desirable to have a swinging door that will open either way. Yet the price of double-acting hinges is three times what it used to be and something that will eliminate this cost is welcome. A strip of hard wood about 1 in. thick and as wide as the door, is hinged to the door- post exactly as if it were the door itself. The door is hinged to this strip, but with the hinges on the other side of the strip. When the door opens one way the strip acts as part of the door-post and one pair of hinges stay closed, while when it opens the other way, the strip acts like a part of the door and the opposite pair of hinges stay closed.— Victor H. Topp. A puttin screen door eliminates the danger of overbalance- ing on narrow steps Noise Eliminators for the Staircase BARE stairway is a noisy ad- junct to a home where there are young children, and one which has a waxed finish makes a constant source of danger that they will slip and get hurt. The ordinary stair carpet, while deadening sound and preventing slipping, is difficult to clean, usually being left down for such long periods that it is not sanitary. One mother has invented pads to cover the middle of each step. The stairs are of natural oak and the pads of ‘‘granite’’ or speckled linoleum of the same shade. They are fastened at BWOING IN . Rin NRE STRIP SS =—— ——SSS : TACKED IN FRONT No necessity now to creep up the stairs at 1 a.m. with your shoes in your hand the front edge with binding metal and fit snugly at the back against the riser. The linoleum deadens sound, is elastic, easy to sweep or to dust with a damp cloth, and its appearance is very neat. Though fastened only at their four margins the pieces lie flat and they are easily lifted when it is necessary to sweep the floor.—Avis G. VESTAL. ae EF een re soc = eis ag ee. scala ~ sien tS “The choiealie of | a satiated earnest (a using: Simonds _ Saws are their % best endorsement” : CN Rh tnt mea Neling > vel a enn tar eg emanate hy, tS fine Mpesecsay te ioe sachets ial Te a ee SS Tie goths ne ode a he $ % : iy tae : it ees i. : : yo 3 ee ee as tees * : : : ‘Sacer eee 3 ee, Ra i x tot te ahi 4 Pes é ea Vane Alkan = \ re ee ee SR a | Be mes ; Po $358 i se Hi es A eae rE 5 oe. Wyte oy bate Ray he a a ee. $Y 3 h plist ay he 5 i ¢ 3 ’ 4 pee 444 ea 3 f 7 " 4 4 : : % +> oe Let ck ‘ ss : 3 _ _-Fitchborg, Massachusetts : ; i ' New York City ; etn | Memphis, Teno. ve _ London, Ex apron B. eit , Montreal, 14) p StJohm, | NB Pde} San; Franc Be Po°% cat Pe oe ET ate x -3 acer sen yh cles ase OR me 183

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wee eee See RS What Says the Record Your machine may be run- ning well so far as eye can tell, but in an hour or a day the output may be way below the standard for that machine. A little difference in operating speed or in mechanical adjust- ment makes a big difference in results,.and only 4 Veeder Counter can measure the dif- ference as your machine works. COUNTERS give you records of production from hour to hour or even from minute to minute, so if you want to know what operating methods or mechanical adjustments give the best results, it’s only a question of what says the record! P = =wh| This Set-Back Revolution Counter records the output of any machine where a shaft revolution indicates an opera- tion. Counts one for each revolution, and sets back to zero from any figure by turning knob once round. Supplied with from four to ten figure wheels, as ordered. Price, with four figures, as illustrated, $8.50. A similar model to count reciprocating movements, as of punch presses, $10.00. (Cut less than 14 _ $1%€.) , The small Rotary Ratchet Counter below counts reciprocating move- ments of the lever, where these indi- cate machine oper- ations. When lever is moved thru an angle of 40 to 60 degrees, the count- er registers one. A complete _revolu- tion of the lever registers ten. A most _adaptabl: counter for recording the output of small machines or experimental work in developing machines. Price, $1.75. (Cut approx. full size.) See the Veeder Booklet for counters suitable for practically every ma- chine and hand-counting purpose. Copy is yours on request. The Veeder Mfg. Co. 44 Sargeant St., _ Hartford, Conn. Popular Science. Monthly Cleaning and Painting the Motorcycle S expert painters are booked up far in advance it is reasonable to expect that if we want our motorcycles cleaned and painted we must do it ourselves. The necessary requirements to do this are not many. A 1-in. flat enamel brush, a 2-in. brush, a small round enamel brush, two sheets of sand- paper (medium and fine) and five cents worth of powdered pumice. Also a can or two of a hard drying enamel, according to the number of coats to be given the surface of the machine. The difference between the trade finish and amateur painting is prin- cipally that in the first instance, dust is excluded while in the amateur job, it falls upon the wet enamel, sticks there and robs the surface of its gloss. Accordingly all care should be taken that the painting is done where there is the least possible amount of dust. | New brushes should be soaked for 12 hours or so, washed with Ivory soap and allowed to dry. This is to secure the bristles. Take the coarser sheet of sandpaper and work each brush backward and forward for five minutes in order to wear down any bristles slightly longer than their fellows. Of course, if you have or can borrow some good brushes which have been in use for some time so much the better. Now to business. Remove the wheels, tank, saddle and small fittings. It does not matter about the handle- | bars or the engine, but these must be thoroughly clean, if dust is to be kept out of our painting. With a hose, or bucket and rags, clean every particle of mud from the frame, taking care that none remains inside the mud- guards. Be liberal with the water; it is the cheapest part of the process and can be quickly wiped from bright fittings. After drying with a cloth, level down all chipped places with the coarse sandpaper and then go over the whole frame with the finer grade. If the chipping is very bad it may be advisable to give these places a coat of enamel before the rubbing down, but it ought not to be necessary with a machine which has been carefully used. After the fine sandpaper has done its best, wrap a duster around some wool or clothes, so as to: form.a. pad.. Moisten it in water and dip it into the powdered pumice. Rub gently over the machine, keeping the strokes 134 ‘at ryt all one way, until the whole surface shows a lustreless evenness. Sponge it off, taking care to remove all the pumice powder, and transfer to the apartment previously prepared. Treat the wheels and the tank in a similar manner, making sure the colors chosen match the originals. If the tank has the baked color finish now so popular, it will be preferable to fill scratches with a fine brush and paint. Then tub down these places very carefully, taking care not to injure the maker’s efforts, and apply one coat of trans- parent varnish. The mere application of the enamel is simplicity itself. At first attempt nearly everybody puts it on _ too thickly, with the It is assumed that the renovation is to be carried out in the machine’s original colors light ‘result that it drains to the lower edges and upon drying forms a solid ridge, leaving the upper portions of the work exceedingly thin. Dip the brush into the color only about a third of the dis- tance up the bris- tles and apply in quick strokes over definite portions of the machine, fin- ishing with short, strokes all going one way. On mudguards and large surfaces general- ly the strokes should be downward, and on the frame tubes they should finish in the direction of the next portion to receive attention. On no ac- count go back after once having left an area—this is positively fatal, and for this reason it is essential to do your best on each section before pass- ing on to the next. The several portions may now be left to dry, and in 24 hours they will be ready for assembling, but to harden properly will require about four days in damp winter weather. To make a thorough job of the process another coat should be given after repeating the rubbing down with powdered pumice. As a result of the second coat the brilliance will last twice as long, and it takes very little extra time. Side-cars, if coach-finished and not too far gone, should have only two coats of varnish put on as thinly and evenly as possible, allowing two days for the first coat to dry. In varnishing, evenness of application is even more imperative than when laying on the enamel, failing which a tendency to patchiness is noticeable. Should the paintwork be badly scratched, rub down, with the pumice and give two coats of enamel of a shade as near as possible to the maker’s choice.

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ace nge the the lar sen nas ar, hes len ly, r’s ns- nel olf, pt 00 he ins reg ng ze, er ut ill September, 1919 Friends of the Motorist Motor Set No. 599 REPARED for the man who guards against long delays on the road, for the enthusiast who matches the quality of his car with the quality of its extras, for the owner who cuts repair expense by the little mechani- cal attention he gives to his car. This set contains twenty-seven tools and is suitable for repairing all ordinary road troubles. The tools come in an extra heavy leather-bound canvas roll and each tool is held firmly in place by broad, strong leather straps. Motorists can feel proud of this kit, for Goodell-Pratt skill and care have entered into its production. The great demand for this high-grade Motor Set proves its value. Your dealer will be glad to show you how complete and handy this set is, or a more detailed description of this or any of the other 1500 Goodell-Pratt Tools will be sent upon request. Motor Set No. 599 contains No. 82 Rim Wrench No. 416 Pin Punch No. 278 Screw Driver No. 455 Cold Chisel No. 359 Thickness Gauge No. 457 Cape Chisel No. 366 Offset Screw Driver No. 462 Half Round Chisel No. 367 Screw Driver, 4inch No. 463 Solid Punch No. 376 Combination Pliers ~ No. 464 Cup Punch No. 413 Pin Punch No. 465 Prick Punch No. No. No. No. No. No. No. 466 Center Punch 474 Double End Wrench 475 Double End Wrench 476 Double End Wrench 479; Cotter Pin Puller 481 Adjustable Wrench 484 Adjustable Wrench GOODELL-PRATT COMPANY nest GREENFIELD, MASS., U. S. A. No. 909 Screw Driver, 3-inch No. 909 Screw Driver, 7-inch 6-inch Three Square File 8-inch Flat File 8-inch Round File 16-ounce Ball Pien Hammer GOODELL PRATT COMPAN 5 SEW TR ELE LOLOL EINER ES, TT TT aa ale Taal PIU AU, 5: Ae PUR

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ew ee

PREVENTS ACCUMULATION OF

‘Popular Science Monthly JOH er CARB ON REMOVER R

AND GUARANTEED By Plolein hie), Pare) A -INE WISCONSIN U-S PATENT APPLIED FOR. Sr = LN

OU can keep your motor snappy and full of “pep” by preventing ‘the accumulation of carbon. choked and caked with it: : ‘Don’t wait until your engine is Use Johnson’s Carbon Remover every 500 miles, then the carbon is removed while it is soft and powdery, eliminating the frequent grinding of valves and ke eeping the motor always clean. No experience or labor required — you can easily do it yourself in ten minutes —and the cost is trifling. <JOHNSON’S [ARBON REMOVER Johnson’s Carbon Remover is a perfectly harmless liquid to be poured or squirted into the cylinders. Millions of cans have been used with ‘satisfaction. It simply softens the carbon, then the heat from the engine pulverizes it and it is blown out the exhaust. Johnson’s Carbon Remover contains no acids and does not affect lubrication.

- JOHNSON’S Hastee Patch This is the ideal repair for tutes, casings and rubber goods of all kinds. No time, labor or heat required. A Patch can te applied in three minutes and it’s so simple a child can use it. Gives equally good results on a pin ~ hole, puncture or on a large blowout. look like new. of repair. JOHNSON’S Black-Lac Here is a preparation with which you can make your gray, dusty top and side curtains Johnson’s Black-Lac is un- equalled for blackening fenders, rims, hoods, lamps—and in fact. all worn metal parts. Pre- vents rust and keeps your car in a high state It is the easiest, cleanest, safest and most satisfactory remedy for carbon. It will save you from $3.00 to $5.00 over any other method without laying up your car. A dose of Johnson’s Carbon Remover--the engine lax- ative—will stop that knock—quiet the motor, and give the maximum power with the minimum amount of fuel.

JOHNSON’S Radiator Cement will stop leaks immediately without laying up the car—no mechanical experience required. Itis absolutely harmless in every respect. It isn't a make-shift—it’s a permanent repair. It will ordinarily seal a leak in from two to ten minutes. A half pint is sufficient for a Ford. For Sale at Leading Hardware and Accessory Stores and Garages

S. C. JOHNSON & SON, Dept. P.S.M., 9 Racine, Wis. ESTABLISHED 1882

33¢

am)